Publication date: Available online 31 May 2017
Source:The Kaohsiung Journal of Medical Sciences
Author(s): Ömer Demir, Ozan Bozkurt, Serdar Çelik, Kaan Çömez, Güven Aslan, Uğur Mungan, İlhan Çelebi, Adil Esen
Aim of this study is to compare the effects of partial nephrectomy (PN) and radical nephrectomy (RN) for stage I renal cell carcinoma (RCC) on renal functions in patients with diabetes mellitus (DM) and/or hypertension (HT). Charts of patients who underwent surgery for stage I RCC in our department were retrospectively reviewed and patients with DM and/or HT were enrolled. Preoperative and postoperative estimated glomerular filtration rates (eGFR) were calculated according to the Modification of Diet in Renal Disease (MDRD) formulation for both RN and PN groups. Groups were compared for patient demographics, preoperative eGFR, postoperative eGFR and ΔeGFR [(preoperative eGFR) – (postoperative eGFR)] which reflects the renal functional loss. There were 85 patients in the RN and 33 patients in the PN groups. Demographic data were similar but the patients in the PN group had smaller tumor size compared to RN group (32.2 ± 11.8 mm vs 47.1 ± 15.2 mm, p < 0.001). Preoperative eGFR did not differ between groups (75 ± 28.4 mL/min/1.73 m2 vs 75.5 ± 23.8 mL/min/1.73 m2 in RN and PN groups, p = 0.929). However, there were significant differences between groups in terms of postoperative eGFR (57.5 ± 21.7 mL/min/1.73 m2 vs 74 ± 27.5 mL/min/1.73 m2 in RN and PN groups, p < 0.001) and ΔeGFR (17.5 ± 4.2 mL/min/1.73 m2 vs 1.5 ± 0.4 mL/min/1.73 m2 in RN and PN groups, p < 0.001). Our findings favor the use of PN over RN for stage I RCC whenever feasible in patients with predisposing systemic diseases for chronic kidney disease for better preservation of renal functions.
http://ift.tt/2rjJ0YU
Τετάρτη 31 Μαΐου 2017
Partial nephrectomy vs. radical nephrectomy for stage I renal cell carcinoma in the presence of predisposing systemic diseases for chronic kidney disease
Interactive effects between Lymphotoxin α +252 polymorphism and habits of substance use on risk of hepatocellular carcinoma
Publication date: Available online 31 May 2017
Source:The Kaohsiung Journal of Medical Sciences
Author(s): Jung-Fa Tsai, Shinn-Chern Chen, Zu-Yau Lin, Chia-Yen Dai, Jee-Fu Huang, Min-Lung Yu, Wan-Long Chuang
This case–control study aimed to assess the interactive effect between polymorphisms of lymphotoxin (LT) α +252 and habitual substance use on risk of hepatocellular carcinoma (HCC). We enrolled 150 pairs of sex- and age-matched HCC patients and unrelated healthy controls. LTα genotypes were detected with polymerase-chain reaction and restrictive fragment length polymorphisms. Information about habits of substance use was obtained through personal interview. Multivariate analysis indicated that LTα +252 G/G genotypes [odds ratio (OR) = 3.36], Hepatitis B surface antigen (OR = 16.68), antibodies to hepatitis C virus (OR = 34.88) and having at least two habits of substance use (OR = 2.50) were independent risk factors for HCC. There were additive interactions among LTα +252 G/G genotype, chronic viral hepatitis, and habit of each substance use. In conclusion: There are independent and additive interactions between LTα +252 G/G genotype, chronic viral hepatitis, and habits of substance use on risk of HCC.
http://ift.tt/2qA57gI
Improved fat transplantation survival by using the conditioned medium of vascular endothelial growth factor transfected human adipose-derived stem cells
Publication date: Available online 31 May 2017
Source:The Kaohsiung Journal of Medical Sciences
Author(s): Yang Zhang, Li-Ling Xiao, Jiang-Xuan Li, Hong-Wei Liu, Sheng-Hong Li, Yan-Yun Wu, Xuan Liao, Cong-Qiang Rao
Autologous fat transplantation has been applied widely in clinic. However, the low survival rate is still a problem to be solved. Studies shows that the human adipose-derived stem cells (ADSCs) transfected by vascular endothelial growth factor (VEGF) can improve the survival rate of autologous fat transplantation. Our study is to evaluate the effects of the conditioned medium of VEGF-transfected human adipose-derived stem cells (VEGF-ADSCs-CM) on fat transplantation. ADSCs were isolated and transfected with MOI = 40. The study was divided into three groups, VEGF-ADSCs-CM group, normal-ADSCs-CM group and control group. The conditioned media for VEGF-ADSCs-CM group and normal-ADSCs-CM group were collected, and then mixed with fat, with the mixtures being injected into the back of nude mice. On 4, 7, 15, 30, 60 days after transplantation, the grafts were evaluated on the wet weight, histology, ELISA and western blot. As the results revealed, the survival rate of VEGF-ADSCs-CM group was highest with the best fat cell morphology, and the VEGF secretion of VEGF-ADSCs-CM group was also highest. Therefore, our study demonstrates that VEGF-ADSCs-CM can improve the survival rate of fat transplantation effectively, and VEGF-ADSCs-CM can be regarded as an effective assisted method for fat transplantation.
http://ift.tt/2rjYGvn
A strabismus syndrome causing chronic innocuous headache
Source:Pediatric Neurology
Author(s): Abhishek Mallick, Rajesh Kumar Singh, Rajeev Kumar Thapar
http://ift.tt/2rjIyK1
Type III spinal cord arteriovenous malformation with good post-surgical outcome
Source:Pediatric Neurology
Author(s): Kabelo Thusang, Keisuke Ueda, Rajkumar Agarwal
http://ift.tt/2qAmLRr
A large saccular aneurysm of the basilar trunk artery in a female child with sudden onset hemiparesis
Source:Pediatric Neurology
Author(s): Young Suh Kim, Young-Mock Lee
http://ift.tt/2rjFH3J
Prevalence of sleep abnormalities in Indian children with Autism Spectrum Disorder; a cross sectional study
Source:Pediatric Neurology
Author(s): R. Aathira, Sheffali Gulati, Manjari Tripathi, Garima Shukla, Biswaroop Chakrabarty, Savita Sapra, Nitika Dang, Anupama Gupta, Madhulika Kabra, R.M. Pandey
BackgroundThe prevalence of Autism spectrum disorder (ASD) is on rise. Apart from the core behavioral issues of impaired communication and social interaction and restricted and/or repeated behavioral phenotype, comorbidities like sleep problems are increasingly getting recognized as important determinants of management and overall quality of life.MethodsThis study was conducted in a tertiary care teaching hospital in north India over a two year period. Children diagnosed with ASD and normally developing children (controls) aged 3 to 10 years were enrolled in the study. Both groups underwent sleep evaluation based on CSHQ (Children's Sleep Habit Questionnaire). Children with ASD also underwent PSG (Polysomnography), CARS (Childhood Autism Rating Scale), CBCL(Childhood Behavioral Checklist) and DP-3(Developmental Profile-3) assessments.ResultsThe prevalence of poor sleepers among ASD and controls were 77.5% (C.I. 66-86.5). and 29.2% (C.I. 18.6-41.5) respectively (p<0.001). The salient findings on PSG were reduced sleep efficiency, decreased REM (rapid eye movement) and SWS (slow wave sleep) duration and desaturation index>1. The CBCL score was significantly high in poor sleepers compared to good sleepers on CSHQ (p=0.004). There was no correlation of CARS or DP-3 score with sleep problems in ASD children.ConclusionsNearly three-fourth of ASD children have sleep abnormalities with possible effect on behavioral phenotype. The PSG findings provide further insight with opportunity for pharmacological interventions. Screening for sleep problems is imperative for appropriate management and overall improvement in quality of life in children with ASD.
http://ift.tt/2qA4sMf
Occurrence of phthalates in aquatic environment and their removal during wastewater treatment processes: a review
Abstract
Phthalates are plasticizers and are concerned environmental endocrine-disrupting compounds. Due to their extensive usage in plastic manufacturing and personal care products as well as the potential to leach out from these products, phthalates have been detected in various aquatic environments including drinking water, groundwater, surface water, and wastewater. The primary source of their environmental occurrence is the discharge of phthalate-laden wastewater and sludge. This review focuses on recent knowledge on the occurrence of phthalate in different aquatic environments and their fate in conventional and advanced wastewater treatment processes. This review also summarizes recent advances in biological removal and degradation mechanisms of phthalates, identifies knowledge gaps, and suggests future research directions.
http://ift.tt/2rjjzGT
Illumina sequencing-based analysis of a microbial community enriched under anaerobic methane oxidation condition coupled to denitrification revealed coexistence of aerobic and anaerobic methanotrophs
Abstract
Methane is produced in anaerobic environments, such as reactors used to treat wastewaters, and can be consumed by methanotrophs. The composition and structure of a microbial community enriched from anaerobic sewage sludge under methane-oxidation condition coupled to denitrification were investigated. Denaturing gradient gel electrophoresis (DGGE) analysis retrieved sequences of Methylocaldum and Chloroflexi. Deep sequencing analysis revealed a complex community that changed over time and was affected by methane concentration. Methylocaldum (8.2%), Methylosinus (2.3%), Methylomonas (0.02%), Methylacidiphilales (0.45%), Nitrospirales (0.18%), and Methanosarcinales (0.3%) were detected. Despite denitrifying conditions provided, Nitrospirales and Methanosarcinales, known to perform anaerobic methane oxidation coupled to denitrification (DAMO) process, were in very low abundance. Results demonstrated that aerobic and anaerobic methanotrophs coexisted in the reactor together with heterotrophic microorganisms, suggesting that a diverse microbial community was important to sustain methanotrophic activity. The methanogenic sludge was a good inoculum to enrich methanotrophs, and cultivation conditions play a selective role in determining community composition.
http://ift.tt/2qAkfKL
Impact of metal stress on the production of secondary metabolites in Pteris vittata L. and associated rhizosphere bacterial communities
Abstract
Plants adapt to metal stress by modifying their metabolism including the production of secondary metabolites in plant tissues. Such changes may impact the diversity and functions of plant associated microbial communities. Our study aimed to evaluate the influence of metals on the secondary metabolism of plants and the indirect impact on rhizosphere bacterial communities. We then compared the secondary metabolites of the hyperaccumulator Pteris vittata L. collected from a contaminated mining site to a non-contaminated site in Vietnam and identified the discriminant metabolites. Our data showed a significant increase in chlorogenic acid derivatives and A-type procyanidin in plant roots at the contaminated site. We hypothesized that the intensive production of these compounds could be part of the antioxidant defense mechanism in response to metals. In parallel, the structure and diversity of bulk soil and rhizosphere communities was studied using high-throughput sequencing. The results showed strong differences in bacterial composition, characterized by the dominance of Proteobacteria and Nitrospira in the contaminated bulk soil, and the enrichment of some potential human pathogens, i.e., Acinetobacter, Mycobacterium, and Cupriavidus in P. vittata's rhizosphere at the mining site. Overall, metal pollution modified the production of P. vittata secondary metabolites and altered the diversity and structure of bacterial communities. Further investigations are needed to understand whether the plant recruits specific bacteria to adapt to metal stress.
http://ift.tt/2rjzDIu
Scholar : Applied Developmental Science, Volume 21, Issue 3, July-September 2017 is now available online on Taylor & Francis Online
|
Lack of K140 immunoreactivity in junctional epidermolysis bullosa skin and keratinocytes associates with misfolded laminin EGF-like (LE) motif 2 of the β3 short arm
Abstract
Recessive mutations in the LAMA3A, LAMB3 and LAMC2 genes coding for laminin-332 (α3aβ3γ2) chains cause different junctional epidermolysis bullosa (JEB) subtypes. Biallelic truncating mutations in any of the three genes usually lead to lack of protein expression resulting in the severe generalized JEB subtype, while missense or splicing mutations in at least one allele lead to reduced expression typical of generalized intermediate or localized JEB. Here, we molecularly characterized an adult JEB patient showing negative skin staining for the anti-β3 chain mAb K140. This antibody recognizes an as yet unidentified epitope within the β3 short arm. The patient harbours a homozygous splicing mutation resulting in major aberrant transcripts with partial skipping of the LAMB3 exon coding for the laminin EGF-like (LE) motif 2 of the β3 short arm (β3-LE2). At protein level, mutation consequences predict a misfolded β3-LE2 motif and, indeed, we found that laminin-332 is correctly assembled but retained in the endoplasmic reticulum (ER) where it co-localizes with the lumenal ER chaperone BiP, leading to dramatically reduced secretion. Lack of K140 reactivity to mutant laminin-332 was confirmed by immunoprecipitation and Western blot analyses. Our findings identify the β3-LE2 subdomain as the region recognized by K140 mAb. In addition, they further show that misfolding of laminin-332 structural motifs and subsequent ER protein retention is a common pathomechanism in JEB generalized intermediate. In addition to be useful for antigen mapping diagnosis of JEB subtypes, this knowledge is relevant to the design of therapeutic strategies aimed at releasing ER-retained laminin-332 in JEB.
This article is protected by copyright. All rights reserved.
http://ift.tt/2rnvkhu
Poster Exhibit Task Force
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2qzOphp
Poster Abstracts
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2qzvT8Z
Editorial Board
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2rjK1QC
A sword that cuts deeper than the skin
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2qA8NPs
Cutaneous nontuberculous mycobacterial infection presenting as the cubital forearm sign
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2rjJkXD
A case of granulomatous pigmented purpuric dermatosis
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2qA1bMY
A case of autochthonous leprosy in an elderly Italian patient leaving in Milan province with peculiar clinical presentation
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2rjWbcb
“Fungus amungus” - A common disease state that is commonly missed: A survey based study
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2qzJmh0
A case of bacilliary angiomatosis with bone involvement in an HIV-infected patient
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2rjJmyB
A case of cellular neurothekeoma on left antecubital fossa
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2qAieOH
Hidradenitis suppurativa presenting as genital “kissing lesions”
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2rjCkd5
A case of cutaneous infantile hemangiomas associated with cardiac dextroposition, hemivertebra, and unilateral renal agenesis
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2qzXB59
A case of DRESS syndrome with acute interstitial nephritis that improved with corticosteroids
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2rjDgyh
A 10-year retrospective review of cutaneous nontuberculous mycobacterium infection in adult patients
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2qzZ4s8
A case of eccrine syringofibroadenoma (ESFA) responding to electron beam radiation therapy
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2rjqEr6
A case of endocrine mucin-producing sweat gland carcinoma
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2qA1584
A 10-year retrospective analysis of leprosy cases in a hospital setup in India: Scenario in post MDT era
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2rjCiBZ
A case of idiopathic histiocytoid Sweet syndrome: A rare sub-variant
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2qzOsJP
A case of indolent lymphoma or lymphoproliferative disorder or both: An update on small/medium pleomorphic T-cell lymphoma
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2rjJhuN
A blend of botanical extracts improves the dermal structure of stretch marks on ex vivo and in vivo skin
Publication date: June 2017
Source:Journal of the American Academy of Dermatology, Volume 76, Issue 6, Supplement 1
http://ift.tt/2qzLxRD
Effect of meteorological factors and geographic location on methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci colonization in the US.
| Related Articles |
Effect of meteorological factors and geographic location on methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci colonization in the US.
PLoS One. 2017;12(5):e0178254
Authors: Blanco N, Perencevich E, Li SS, Morgan DJ, Pineles L, Johnson JK, Robinson G, Anderson DJ, Jacob JT, Maragakis LL, Harris AD, CDC Prevention Epicenter Program
Abstract
BACKGROUND: Little is known about the effect of meteorological conditions and geographical location on bacterial colonization rates particularly of antibiotic-resistant Gram-positive bacteria. We aimed to evaluate the effect of season, meteorological factors, and geographic location on methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) colonization.
METHODS: The prospective cohort included all adults admitted to 20 geographically-dispersed ICUs across the US from September 1, 2011 to October 4, 2012. Nasal and perianal swabs were collected at admission and tested for MRSA and VRE colonization respectively. Poisson regression models using monthly aggregated colonization counts as the outcome and mean temperature, relative humidity, total precipitation, season, and/or latitude as predictors were constructed for each pathogen.
RESULTS: A total of 24,704 ICU-admitted patients were tested for MRSA and 24,468 for VRE. On admission, 10% of patients were colonized with MRSA and 12% with VRE. For MRSA and VRE, a 10% increase in relative humidity was associated with approximately a 9% increase in prevalence rate. Southerly latitudes in the US were associated with higher MRSA colonization, while northerly latitudes were associated with higher VRE colonization. In contrast to MRSA, the association between VRE colonization and latitude was observed only after adjusting for relative humidity, which demonstrates how this effect is highly driven by this meteorological factor.
CONCLUSIONS: To our knowledge, we are the first to study the effect of meteorological factors and geographical location/latitude on MRSA and VRE colonization in adults. Increasing humidity was associated with greater MRSA and VRE colonization. Southerly latitudes in the US were associated with greater MRSA and less VRE. The effect of these factors on MRSA and VRE rates has the potential not only to inform patient management and treatment, but also infection prevention interventions.
PMID: 28558010 [PubMed - in process]
http://ift.tt/2qzNxsR
Elimination of cancer stem cells and reactivation of latent HIV-1 via AMPK activation: Common mechanism of action linking inhibition of tumorigenesis and the potential eradication of HIV-1
Source:Medical Hypotheses
Author(s): Jahahreeh Finley
Although promising treatments are currently in development to slow disease progression and increase patient survival, cancer remains the second leading cause of death in the United States. Cancer treatment modalities commonly include chemoradiation and therapies that target components of aberrantly activated signaling pathways. However, treatment resistance is a common occurrence and recent evidence indicates that the existence of cancer stem cells (CSCs) may underlie the limited efficacy and inability of current treatments to effectuate a cure. CSCs, which are largely resistant to chemoradiation therapy, are a subpopulation of cancer cells that exhibit characteristics similar to embryonic stem cells (ESCs), including self-renewal, multi-lineage differentiation, and the ability to initiate tumorigenesis. Interestingly, intracellular mechanisms that sustain quiescence and promote self-renewal in adult stem cells (ASCs) and CSCs likely also function to maintain latency of HIV-1 in CD4+ memory T cells. Although antiretroviral therapy is highly effective in controlling HIV-1 replication, the persistence of latent but replication-competent proviruses necessitates the development of compounds that are capable of selectively reactivating the latent virus, a method known as the "shock and kill" approach. Homeostatic proliferation in central CD4+ memory T (TCM) cells, a memory T cell subset that exhibits limited self-renewal and differentiation and is a primary reservoir for latent HIV-1, has been shown to reinforce and stabilize the latent reservoir in the absence of T cell activation and differentiation. HIV-1 has also been found to establish durable and long-lasting latency in a recently discovered subset of CD4+ T cells known as T memory stem (TSCM) cells. TSCM cells, compared to TCM cells, exhibit stem cell properties that more closely match those of ESCs and ASCs, including self-renewal and differentiation into all memory T cell subsets. It is our hypothesis that activation of AMPK, a master regulator of cellular metabolism that plays a critical role in T cell activation and differentiation of ESCs and ASCs, will lead to both T cell activation-induced latent HIV-1 reactivation, facilitating virus destruction, as well as "activation", differentiation, and/or apoptosis of CSCs, thus inhibiting tumorigenesis. We also propose the novel observation that compounds that have been shown to both facilitate latent HIV-1 reactivation and promote CSC differentiation/apoptosis (e.g. bryostatin-1, JQ1, metformin, butyrate, etc.) likely do so through a common mechanism of AMPK activation.
http://ift.tt/2sdkFEb
Scholar : These new articles for CoDesign are available online
|
Diesel reformulation using bio-derived propanol to control toxic emissions from a light-duty agricultural diesel engine
Abstract
In the Indian agricultural sector, millions of diesel-driven pump-sets were used for irrigation purposes. These engines produce carcinogenic diesel particulates, toxic nitrogen oxides (NOx), and carbon monoxide (CO) emissions which threaten the livelihood of large population of farmers in India. The present study investigates the use of n-propanol, a less-explored high carbon bio-alcohol that can be produced by sustainable pathways from industrial and crop wastes that has an attractive opportunity for powering stationary diesel engines meant for irrigation and rural electrification. This study evaluates the use of n-propanol addition in fossil diesel by up to 30% by vol. and concurrently reports the effects of exhaust gas recirculation (EGR) on emissions of an agricultural DI diesel engine. Three blends PR10, PR20, and PR30 were prepared by mixing 10, 20, and 30% by vol. of n-propanol with fossil diesel. Results when compared to baseline diesel case indicated that smoke density reduced with increasing n-propanol fraction in the blends. PR10, PR20, and PR30 reduced smoke density by 13.33, 33.33, and 60%, respectively. NOx emissions increased with increasing n-propanol fraction in the blends. Later, three EGR rates (10, 20, and 30%) were employed. At any particular EGR rate, smoke density remained lower with increasing n-propanol content in the blends under increasing EGR rates. NOx reduced gradually with EGR. At 30% EGR, the blends PR10, PR20, and PR30 reduced NOx emissions by 43.04, 37.98, and 34.86%, respectively when compared to baseline diesel. CO emissions remained low but hydrocarbon (HC) emissions were high for n-propanol/diesel blends under EGR. Study confirmed that n-propanol could be used by up to 30% by vol. with diesel and the blends delivered lower soot density, NOx, and CO emissions under EGR.
http://ift.tt/2slA1pc
Electro-Fenton oxidation of para-aminosalicylic acid: degradation kinetics and mineralization pathway using Pt/carbon-felt and BDD/carbon-felt cells
Abstract
Degradation of a widely used antibiotic, the para-aminosalicylic acid (PAS), and mineralization of its aqueous solution was investigated by electro-Fenton process using Pt/carbon-felt and boron-doped diamond (BDD)/carbon-felt cells with applied currents in the range of 50–1000 mA. This process produces the highly oxidizing species, the hydroxyl radical (•OH), which is mainly responsible for the oxidative degradation of PAS. An absolute rate constant of 4.17 × 109 M−1 s−1 for the oxidation of PAS by ●OH was determined from the competition kinetics method. Degradation rate of PAS increased with current reaching an optimal value of 500 mA with complete disappearance of 0.1 mM PAS at 7 min using Pt/carbon-felt cell. The optimum degradation rate was reached at 300 mA for BDD/carbon-felt. The latter cell was found more efficient in total organic carbon (TOC) removal where a complete mineralization was achieved within 240 min. A multi-step mineralization process was observed with the formation of a number of aromatic intermediates, short-chain carboxylic acids, and inorganic ions. Eight aromatic intermediate products were identified using both LC-Q-ToF-MS and GC-MS techniques. These products were the result of hydroxylation of PAS followed by multiple additions of hydroxyl radicals to form polyhydroxylated derivatives. HPLC and GC/MS analyses demonstrated that extended oxidation of these intermediate products conducted to the formation of various short-chain carboxylic acids. Prolonged electrolysis resulted in a complete mineralization of PAS with the evolution of inorganic ions such as NO3− and NH4+. Based on the identified intermediates, carboxylic acids and inorganic ions, a plausible mineralization pathway is also deduced. The remarkably high degree of mineralization (100%) achieved by the present EF process highlights the potential application of this technique to the complete removal of salicylic acid-based pharmaceuticals from contaminated water.
http://ift.tt/2rnMprz
Exposure assessment of honeybees through study of hive matrices: analysis of selected pesticide residues in honeybees, beebread, and beeswax from French beehives by LC-MS/MS
Abstract
Apiculture and pollination services are seriously threatened by bee weakening and losses phenomena. In this context, a survey was performed on samples from beehives across French areas during the 2012–2016 growing seasons, primarily taken from symptomatic colonies. A total of 488 honeybees, beebread, and wax were analyzed for the presence of pesticide residues. A total of 13 analytes including neonicotinoids and pyrethroids insecticides together with some of their metabolites and the fungicide boscalid were screened within samples. Methodologies based on efficient modified quick, easy, cheap, effective, rugged, and safe extractions followed by an LC-MS/MS quantification were implemented for each matrix. Thirty-eight percent of the 125 bee samples, 61% of the 87 wax samples, and 77% of the 276 beebread samples contained at least one of the targeted pesticides. Beebread was the most contaminated matrix with an average of two pesticide detections by positive sample and a maximum of seven compounds for a sample. Neonicotinoids and boscalid were the most often detected pesticides, whatever the matrix. The comparison of neonicotinoid detections in samples collected before and after the partial neonicotinoid ban in France displays a decrease in the frequency of detections for contamination levels lower than 1 ng/g in beebread. For higher levels and other matrices, no tendency can be drawn.
http://ift.tt/2slsfMg
Fullerol C 60 (OH) 24 nanoparticles and mycotoxigenic fungi: a preliminary investigation into modulation of mycotoxin production
Abstract
Increased use of fullerols in various fields and expected increase of their environmental spread impose the necessity for testing fullerol nanoparticles (FNP) effects on microbiota. There is little information available on the interaction of mycotoxigenic fungi and FNP, despite FNP having a great potential of modifying mycotoxin production. Namely, FNP exhibit both ROS-quenching and ROS-producing properties, while oxidative stress stimulates mycotoxin synthesis in the fungi. In order to shed some light on the extent of interaction between FNP and mycotoxigenic fungi, the effects of fullerol C60(OH)24 nanoparticles (10, 100, 1000 ng/mL) on mycelial growth, aflatoxin production and oxidative stress modulation in an aflatoxigenic strain of Aspergillus flavus (NRRL 3251) during 168 h of incubation in a liquid culture medium were examined. FNP slightly reduced mycelial biomass weight, but significantly decreased aflatoxin concentration in media. Lipid peroxide content, superoxide dismutase, catalase and glutathione peroxidase activities suggest that FNP treatments hormetically reduced oxidative stress within fungal cells in turn suppressing aflatoxin production. These findings contribute to the assessment of environmental risk and application potential of fullerols.
http://ift.tt/2slAoQz
Use of halophytes in pilot-scale horizontal flow constructed wetland treating domestic wastewater
Abstract
Recent findings encourage the use of halophytes in constructed wetlands for domestic wastewater treatment due to their special physiological characteristics as the ability to accumulate heavy metals and salts in their tissues makes them ideal candidates for constructed wetland vegetation. In this particular study, we investigated the application of halophytic plants in a horizontal flow constructed wetland for domestic wastewater treatment purposes. The pilot plant which was situated in Crete (Greece) was planted with a polyculture of halophytes (Tamarix parviflora, Juncus acutus, Sarcocornia perrenis, and Limoniastrum monopetalum). The system's performance was monitored for a period of 11 months during which it received primary treated wastewater from the local wastewater treatment plant. Results show that halophytes developed successfully in the constructed wetland and achieved organic matter and pathogen removal efficiencies comparable to those reported for reeds in previous works (63% and 1.6 log units, respectively). In addition, boron concentration in the effluent was reduced by 40% in comparison with the influent. Salinity as expressed by electrical conductivity did not change during the treatment, indicating that the accumulation of salts in the leaves is not able to overcome electrical conductivity increasing due to evapotranspiration. The results indicate an improvement in the treatment of domestic wastewater via the use of halophyte-planted CWs.
http://ift.tt/2rnllZF
Fate of selected drugs in the wastewater treatment plants (WWTPs) for domestic sewage
Abstract
The wide diffusion of Emerging Organic Micropollutants (EOMs) in the environment is receiving increasing attention due to their potential toxicological effects on living organisms. So far, the Wastewater Treatment Plants (WWTPs) have not been designed with the purpose to remove these contaminants; therefore, they can represent the major source of release into the environment both through the effluent and the wasted sludge. The fate of EOMs in the WWTPs is still not completely known; further investigations are therefore needed to assess if it is possible to exploit the existing treatment units to reduce EOM concentrations or which processes must be implemented to this purpose. Among the wide class of EOMs, the present study focused on the following drugs of abuse: amphetamine (AM), methamphetamine (MET), 11-nor-Δ9-THC-9carboxy (THC-COOH) and benzoylecgonine (BEG). Presence and removal efficiency of these drugs in the activated sludge tank of a WWTP for domestic sewage was investigated through analyses at both full-scale and laboratory scale. Determinations conducted in the full-scale WWTP highlighted that, among the searched drugs, AM was found to be the most abundant in the influent and effluent of the biological oxidation tank, while 11-nor-Δ9-THC-9carboxy was present at the lowest concentration. Some removal took place in the units prior to the oxidation tank, although the main reduction was observed to occur in the biological oxidation reactor. All the drugs showed a wide variability of the measured concentrations during the week and the day. Taking into account results from both full-scale observations and batch tests, removals in the biological reactor were found within the following ranges: 33–84% for AM, 33–97% for MET, 33–57% for BEG and 29–83% for THC-COOH. These removals were due to a combination of adsorption and biodegradation mainly, while volatilization did not play a significant role. Other processes, e.g. hydrolysis, were likely to occur.
http://ift.tt/2slVb6y
Extreme learning machines: a new approach for modeling dissolved oxygen (DO) concentration with and without water quality variables as predictors
Abstract
In this paper, several extreme learning machine (ELM) models, including standard extreme learning machine with sigmoid activation function (S-ELM), extreme learning machine with radial basis activation function (R-ELM), online sequential extreme learning machine (OS-ELM), and optimally pruned extreme learning machine (OP-ELM), are newly applied for predicting dissolved oxygen concentration with and without water quality variables as predictors. Firstly, using data from eight United States Geological Survey (USGS) stations located in different rivers basins, USA, the S-ELM, R-ELM, OS-ELM, and OP-ELM were compared against the measured dissolved oxygen (DO) using four water quality variables, water temperature, specific conductance, turbidity, and pH, as predictors. For each station, we used data measured at an hourly time step for a period of 4 years. The dataset was divided into a training set (70%) and a validation set (30%). We selected several combinations of the water quality variables as inputs for each ELM model and six different scenarios were compared. Secondly, an attempt was made to predict DO concentration without water quality variables. To achieve this goal, we used the year numbers, 2008, 2009, etc., month numbers from (1) to (12), day numbers from (1) to (31) and hour numbers from (00:00) to (24:00) as predictors. Thirdly, the best ELM models were trained using validation dataset and tested with the training dataset. The performances of the four ELM models were evaluated using four statistical indices: the coefficient of correlation (R), the Nash-Sutcliffe efficiency (NSE), the root mean squared error (RMSE), and the mean absolute error (MAE). Results obtained from the eight stations indicated that: (i) the best results were obtained by the S-ELM, R-ELM, OS-ELM, and OP-ELM models having four water quality variables as predictors; (ii) out of eight stations, the OP-ELM performed better than the other three ELM models at seven stations while the R-ELM performed the best at one station. The OS-ELM models performed the worst and provided the lowest accuracy; (iii) for predicting DO without water quality variables, the R-ELM performed the best at seven stations followed by the S-ELM in the second place and the OP-ELM performed the worst with low accuracy; (iv) for the final application where training ELM models with validation dataset and testing with training dataset, the OP-ELM provided the best accuracy using water quality variables and the R-ELM performed the best at all eight stations without water quality variables. Fourthly, and finally, we compared the results obtained from different ELM models with those obtained using multiple linear regression (MLR) and multilayer perceptron neural network (MLPNN). Results obtained using MLPNN and MLR models reveal that: (i) using water quality variables as predictors, the MLR performed the worst and provided the lowest accuracy in all stations; (ii) MLPNN was ranked in the second place at two stations, in the third place at four stations, and finally, in the fourth place at two stations, (iii) for predicting DO without water quality variables, MLPNN is ranked in the second place at five stations, and ranked in the third, fourth, and fifth places in the remaining three stations, while MLR was ranked in the last place with very low accuracy at all stations. Overall, the results suggest that the ELM is more effective than the MLPNN and MLR for modelling DO concentration in river ecosystems.
http://ift.tt/2rnMmvT
Testing the EKC hypothesis by considering trade openness, urbanization, and financial development: the case of Turkey
Abstract
This study investigates the environmental Kuznets curve (EKC) hypothesis for the case of Turkey from 1960 to 2013 by considering energy consumption, trade, urbanization, and financial development variables. Although previous literature examines various aspects of the EKC hypothesis for the case of Turkey, our model augments the basic model with several covariates to develop a better understanding of the relationship among the variables and to refrain from omitted variable bias. The results of the bounds test and the error correction model under autoregressive distributed lag mechanism suggest long-run relationships among the variables as well as proof of the EKC and the scale effect in Turkey. A conditional Granger causality test reveals that there are causal relationships among the variables. Our findings can have policy implications including the imposition of a "polluter pays" mechanism, such as the implementation of a carbon tax for pollution trading, to raise the urban population's awareness about the importance of adopting renewable energy and to support clean, environmentally friendly technology.
http://ift.tt/2slynUP
Urinary metabolomic profiling in rats exposed to dietary di(2-ethylhexyl) phthalate (DEHP) using ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS)
Abstract
Di(2-ethylhexyl) phthalate (DEHP) is an omnipresent environmental chemical with widespread nonoccupational human exposure through multiple ways. Although considerable efforts have been invested to investigate mechanisms of DEHP toxicity, the key metabolic biomarkers of DEHP toxicity remain to be identified. The aim of this study was to assess the urinary metabonomics of dietary DEHP in rats using the technique of ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS). Fourteen female Wistar rats were divided into two groups and given increasing dietary doses of DEHP for 30 consecutive days. The urinary metabolite profile was studied using ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry. Principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) enabled clusters to be clearly separated. Eleven principal urinary metabolites were identified as contributing to the clusters. The clusters in the positive electrospray ionization (ESI) mode were xanthurenic acid, kynurenic acid, nonate, N6-methyladenosine, and L-isoleucyl-L-proline. The clusters in the negative ESI mode were hippuric acid, tetrahydrocortisol, citric acid, phenylpropionylglycine, cPA(18:2(9Z, 12Z)/0:0), and LysoPC(14:1(9Z)). The urinary metabonomic changes indicated that exposure to dietary DEHP can affect energy-related metabolism, liver and renal function, fatty acid metabolism, and cause DNA damage in rats. The findings of this study on the urinary metabolites and metabolic pathways of DEHP may form the basis for future studies on the mechanisms of toxicity of this commonly found environmental chemical.
http://ift.tt/2rnlHzm
Radiofrequency treatment induces fibroblast growth factor 2 expression and subsequently promotes neocollagenesis and neoangiogenesis in the skin tissue
Abstract
Radiofrequency (RF) treatment appears to be involved in production of new collagen fibrils and the improvement of existing collagen structures; however, the molecular bases of the effect of non-invasive RF on the skin tissue have not been fully elucidated. This study reports the effects of RF associated or not with hydrolyzed collagen (HC) in the skin tissue. Wistar rats were randomly divided into four groups, according to the treatment received: control group (G1, n = 5), no treatment; subjects in group G2 (n = 5) were treated with HC; and capacitive RF was applied to the back of each subject in G3 (n = 5) and RF associated with HC in G4 (n = 5). Biopsies were taken 30 days after treatment and then were histologically processed and studied for inflammatory cell counting, collagen content, and morphometry. In addition, FGF2, CD105, and COX-2 expression was assessed by immunohistochemical staining. The most relevant changes were the increase in cellularity and accumulation of intercellular substance in RF-treated animals (G3 and G4). The greatest dermis thickness rate was observed in G4, followed by G3 and G2 (p < 0.05). RF-treated skins (G3 and G4) exhibited a significant overexpression of FGF2 (p < 0.0001) and increased microvessel density (p < 0.0001) in comparison with G1 and G2. Moreover, the amount of COX-2 was significantly higher (p < 0.0001) in dermis of RF-treated areas compared to G1 and G2, and demonstrated differences in G3 (RF) compared to G4 (RF + HC) (p < 0.0001). Our results suggests that RF treatment associated or not with HC induces FGF2 overexpression, promotes neoangiogenesis and modulates the COX-2 expression, subsequently promotes neocollagenesis, and increased thickness rate of dermis.
http://ift.tt/2rTRYP2
Editorial Board
Source:Cancer Treatment Reviews, Volume 57
http://ift.tt/2rE1NRK
Designing biologically inspired heat conduction paths for ‘volume-to-point’ problems
Publication date: 15 September 2017
Source:Materials & Design, Volume 130
Author(s): Baotong Li, Jun Hong, Liuhua Ge, Chengbin Xuan
In this article, an evolutionary algorithm is presented for constructal optimization of high conductivity paths by mimicking the morphogenesis of leaf veins in nature. To get a physically meaningful continuous path solution, the optimization is conducted as a sequence of growth steps which begins with the heat sink and proceeds toward the whole conduction domain. The growth simulation is explored by making use of the interpolation scheme called "conductivity spreading approach" (CSA). Unlike other evolutionary algorithms, the CSA method separates growing channels from the underlying ground structure so that the growth dependency on node locations and element connections is eliminated and cooling channels are provided with more flexibility to grow toward an arbitrary direction in the conduction domain. Notably, this approach incorporates more geometry and thermal information into constructal optimization and improves the definiteness of frontiers between high and low conductivity materials. The feasibility and effectiveness of the proposed method are demonstrated in examples of 'volume-to-point' heat conduction, which forms at convergence a dendritic configuration. In addition, the influence of different design objectives, like the thermal compliance, average temperature and temperature variance, on the resulting dendritic configurations is discussed through both numerical analyses and experimental tests.
Graphical abstract
http://ift.tt/2rDOikL
Developing polyimide-copper antifouling coatings with capsule structures for sustainable release of copper
Publication date: 15 September 2017
Source:Materials & Design, Volume 130
Author(s): Yi Liu, Xinkun Suo, Zhe Wang, Yongfeng Gong, Xin Wang, Hua Li
Polyimide-copper layers consisting of individual capsule-like splats were one-step fabricated by solution precursor flame spray through controlling the reaction between dianhydride and diamine dissolved in copper nanoparticles-containing dimethylformamide solvent. The polyimide splat exhibited hollow structure with an inner pore of 10–15μm and a tiny hole of 1–5μm on its top surface. Transversal cut by focused ion beam milling of the individual splats and scanning electron microscopy characterization further revealed unique dispersion of the copper nanoparticles inside the polyimide shell. After 1000h exposure to the testing synthetic seawater, continuous release of copper from the coatings containing up to 30wt%Cu kept remarkable. Antifouling performances of the constructed layers were assessed by examining colonization behaviors of typical bacteria Bacillus sp. and marine algae Phaeodactylum tricornutum and Chlorella on their surfaces. Distribution of the inorganic nanoparticles endows the polyimide coatings with special capsule structure and exciting hydrophobicity and antifouling performances. The liquid flame spray route and the encapsulated structure of the polyimide-Cu coatings would open a new window for designing and constructing environment-friendly marine antifouling layers for long-term applications.
Graphical abstract
http://ift.tt/2rE1Ug8
Isothermal kinetics of β↔α transformation in Ti-55531 alloy influenced by phase composition and microstructure
Publication date: 15 September 2017
Source:Materials & Design, Volume 130
Author(s): Fuwen Chen, Guanglong Xu, Xiaoyong Zhang, Kechao Zhou
The different β↔α phase transformation behaviors in Ti-55531 alloys with three types of preset microstructure were studied at isothermal conditions in the temperature range of 450–750°C. The dilatometry was employed to record the length change of the specimen. TTT diagrams for alloys with different microstructure were plotted based on the phase fractions of transformed α at different temperatures. With the help of Johnson–Mehl–Avrami theory, the calculated kinetic curves were in good agreement with experimental results. The β→secondary α transformation in the alloy with preset 'β-quenched' microstructure took place at higher nose temperature with a shorter incubation time in comparison with others, but exhibited lower steady transformation rate than that with preset 'β+αequiaxed' microstructure. With local composition analyses, the high nose temperature was interpreted by the difference in β stability and supersaturation. The alloy with preset 'β+αequiaxed' microstructure showed higher transformation rate than that with preset 'β+αlamellar' microstructure, which might be associated with the richness of defects.
Graphical abstract
http://ift.tt/2rDFVFY
Corrigendum to “Controlled nanoscale precipitation to enhance the mechanical and biological performances of a metastable β Ti-Nb-Sn alloy for orthopedic applications” [Mater. Des. 126 (2017) 226–237]
Publication date: 15 September 2017
Source:Materials & Design, Volume 130
Author(s): Sumit Bahl, Akash S. Krishnamurthy, Satyam Suwas, Kaushik Chatterjee
http://ift.tt/2rDKdgD
Design, fabrication and characterization of TiO2-SiO2 multilayer with tailored color glazing for thermal solar collectors
Publication date: 15 September 2017
Source:Materials & Design, Volume 130
Author(s): Iulian Pana, Catalin Vitelaru, Adrian Kiss, Nicolae Catalin Zoita, Mihaela Dinu, Mariana Braic
The paper reports on the design, fabrication, and characterization of a 7-layer SiO2-TiO2 colored coating for solar thermal façades. A combined theoretical and experimental approach was employed for designing the colored coating by using optical modeling and individual layers characterization, targeting for high solar transmittance and pronounced yellow-green reflected color. SiO2-TiO2 multilayers were deposited on glass and silicon substrates by using the reactive RF magnetron sputtering of stoichiometric oxide targets. The coatings were investigated by UV–Vis spectrophotometric methods for optical properties, surface profilometry, X ray reflectivity and SEM for the thickness of individual layers composing the multilayer and AFM for surface roughness. Hardness H, reduced modulus Er, and adhesion were determined by nanoindentation and scratch tests. The deposited colored glazing exhibited a prominent reflectivity peak of ~54% centered at 574nm, specific visible reflectance of ~45.39% and an integrated solar transmittance of about 80.3%. Its optical properties were preserved in the ambient for temperatures up to 200°C and the color was not modified for incidence angles up to 45°. H values of 7.18GPa, Er of 88.31GPa, H/Er ratio of about 0.081 and good scratch resistance up to 13mN were measured.
Graphical abstract
http://ift.tt/2sd7XoG
Facile fabrication of three-dimensional porous CuFe2O4 cages as highly efficient and recyclable heterogeneous catalyst
Publication date: 15 September 2017
Source:Materials & Design, Volume 130
Author(s): Yu-Ting Zhuang, Wei Gao, Yong-Liang Yu, Jian-Hua Wang
The design and preparation of high-performance catalysts with high catalytic activity and excellent durability that are both environmentally benign and cost-effective remains a considerable challenge. Herein, a facile strategy is reported for the fabrication of three-dimensional porous CuFe2O4 cages, shortly as 3D CuFe2O4@C, by bubbling oxygen produced in situ through a CuFe2O4 suspension, followed by thermal treatment in nitrogen atmosphere. The 3D CuFe2O4@C structure increases the surface area of CuFe2O4 and provides a porous support structure. It is proposed to be a key in preventing the aggregation of CuFe2O4 during practical use. 3D CuFe2O4@C is shown to be a highly active catalyst, not only for the hydrogenation of p-nitrophenol, but also for the reduction of methylene blue in aqueous medium. 3D CuFe2O4@C exhibits remarkable catalytic activity towards p-nitrophenol reduction, with a catalytic rate constant of 2.167min−1 that is 5.35 times higher than that with pristine CuFe2O4 (0.405min−1). In addition, the 3D CuFe2O4@C catalyst has a high saturation magnetization of 51.9emug−1, indicating that it can be easily recycled using a magnet. The 3D porous metal oxide nanostructure shows promising potentials as candidates for the remediation of contaminated aquatic environments and meets the demands for addressing future environmental issues.
Graphical abstract
http://ift.tt/2sdwxpQ
Easy batch-scale production of cobalt ferrite nanopowders by two-step milling: Structural and magnetic characterization
Publication date: 15 September 2017
Source:Materials & Design, Volume 130
Author(s): Pietro Galizia, Marin Cernea, Valentina Mihalache, Lucian Diamandescu, Giovanni Maizza, Carmen Galassi
Cobalt ferrite (CF) powder was synthesized by solid state reaction method at two different calcination temperatures (1120 K and 1320 K) then milled in two steps, gradually reducing the milling media size. The first milling step results in CF nanoparticles with crystallite size of 33nm showing fairly high coercivity (3.7kOe), >5 times higher than the non-milled material (0.7kOe). The high coercivity was correlated to the crystallite size close to the single-domain limit, and to the strain increase up to 2.1%. This value of strain is the highest ever reported in literature for the CF and brings to the highest figure of merit for permanent magnets, (BH)max=2.16MGOe. After the second milling step the powder displays particle size of 9nm, release of strain (ε=1.2%), coercivity reduction that approaches 250Oe and decrease of the deblocking temperature from 421 K to 317 K. The large tunability obtained by multi-step milling allows to use CF in different applications. In particular, the milled CF powder characterized by high microstrain is a good candidate for the realization of rare-earth-free permanent magnets (at least on the basis of the (BH)max product). For the first time, a correlation between the spin-canting angle and the degree of inversion, the crystallite size and the microstrain is presented and discussed.
Graphical abstract
http://ift.tt/2sd0lCF
Process-induced bottom defects in clinch forming: Simulation and effect on the structural integrity of single shear lap specimens
Publication date: 15 September 2017
Source:Materials & Design, Volume 130
Author(s): S. Coppieters, H. Zhang, F. Xu, N. Vandermeiren, A. Breda, D. Debruyne
Lightweight and high strength sheet metal such as aluminum alloy sheets are used in a variety of industrial applications. Due to the limited weldability of these materials, mechanical joining techniques such as clinching are of interest. The challenge in this regard is that conventional round clinch forming locally induces large plastic deformations which potentially cannot be accommodated by materials with limited ductility. Ductile damage models are used to predict the occurrence of bottom cracks during conventional round clinch forming of EN AW-6082 T6 sheet. It is shown that cracks in the bottom of a clinched joint and the final static strength of a single lap shear specimen can be numerically reproduced provided that the post-necking strain hardening behavior and damage behavior of the base material are properly identified. The observed bottom cracks did not have a detrimental effect on the static strength and fatigue life of single shear lap specimens. It is hypothesized that fatigue cracks in single shear lap tests initiate due to fretting.
Graphical abstract
http://ift.tt/2sdjGUr
Superparamagnetic core-shell nanocomplexes doped with Yb3+: Er3+/Ho3+ rare-earths for upconversion fluorescence
Publication date: 15 September 2017
Source:Materials & Design, Volume 130
Author(s): Isabel Campos-Gonçalves, Benilde F.O. Costa, Rúben F. Santos, Luísa Durães
This work aims to obtain multifunctional nanocomplexes with a superparamagnetic core and an upconversion luminescent shell, by synthesizing superparamagnetic iron oxide nanoparticles (SPIONs) functionalized with lanthanide ions. These materials may be used in numerous applications, e.g. in the biomedical and environmental fields. Three distinct nanocomplexes were synthesized: SPIONs@LaF3:Yb3+/Er3+, SPIONs@NaYF4:Yb3+/Er3+ and SPIONs@NaYF4:Yb3+/Ho3+. The first was obtained using the microemulsion and co-precipitation methods and the latter using the thermal decomposition method. A heat treatment was also applied to the SPIONs@LaF3:Yb3+/Er3+ nanocomplex. VSM revealed the superparamagnetic character of the nanocomplexes, and the saturation magnetization was 10.2emu·g−1, 8.4emu·g−1, 8.3emu·g−1 and 14.0emu·g−1 for SPIONs@LaF3:Yb3+/Er3+ without and with heat treatment, SPIONs@NaYF4:Yb3+/Er3+ and SPIONs@NaYF4:Yb3+/Ho3+ nanocomplexes, respectively. The upconversion process in these materials was confirmed by multiphoton microscopy. For SPIONs@NaYF4:Yb3+/Er3+, three peaks of emission were obtained, at 520nm, 540nm and 657nm, while for SPIONs@NaYF4:Yb3+/Ho3+ and SPIONs@LaF3:Yb3+/Er3+ samples only two peaks were observed, at 540nm and 647nm for the first, and at 540nm and 657nm for the latter. The results for the nanocomplex which uses Ho3+ ions as activators are very promising, since similar nanocomplexes are yet to be reported and good magnetic and luminescent properties were achieved.
Graphical abstract
http://ift.tt/2sdbIL6
Real-time electromagnetic tracking–based treatment platform for high-dose-rate prostate brachytherapy: Clinical workflows and end-to-end validation
Source:Brachytherapy
Author(s): Luc Beaulieu, Emmanuel Racine, Dae Yup Han, Eric Vigneault, I-Chow Hsu, J. Adam M. Cunha
PurposeNew technologies were integrated into a novel treatment platform combining electromagnetically (EM) tracked catheters, a 3D ultrasound (3DUS) imaging device, and a new treatment planning system to provide a real-time prostate high-dose-rate (HDR) brachytherapy treatment system. This work defines workflows for offline CT and online 3DUS planning scenarios and preclinical end-to-end validation of the platform.Methods and MaterialsThe platform is composed of an EM-tracked stylet, a EM-tracked 3DUS probe, and an EM-tracked template guide, all used with the NDI Aurora field generator (NDI, Ontario, Canada). The treatment planning system performs continuous position and angular readings from all three EM sensors into a streamlined environment that allows for (1) contouring; (2) planning; (3) catheter insertion guidance and reconstruction; (4) QA of catheter path and tip position; and (5) exporting to an afterloader. Data were gathered on the times required for the various key steps of the 3DUS-based workflow.ResultsThe complete 3DUS-based workflow on 16-catheter implant phantoms took approximately 15 min. This time is expected to increase for actual patients. Plan generation is fast (7.6 ± 2.5s) and the initial catheter reconstruction with updated dose distribution is obtained at no (time) cost as part of the insertion process. Subsequent catheter reconstruction takes on average 10.5 ± 3.1s per catheter, representing less than 3 min for a 16-catheter implant.ConclusionsThis preclinical study suggests that EM technology could help to significantly streamline real-time US-based high-dose-rate prostate brachytherapy.
http://ift.tt/2qFdvX7
Scholar : These new articles for Asian Security are available online
|
The role of nailfoldcapillaroscopy in the assessment of internal organ involvement in Systemic Sclerosis: A critical review
Source:Autoimmunity Reviews
Author(s): Stergios Soulaidopoulos, Eva Triantafyllidou, Alexandros Garyfallos, George D. Kitas, Theodoros Dimitroulas
Endothelial dysfunction and microvascular damage constitute the hallmarks of systemic sclerosis (SSc), explaining much of the pathophysiology and clinical manifestations of the disease. Nailfold videocapillaroscopy (NVC) is an established method for the assessment of the microvasculature, aiding in distinguishing different types of structural vascular abnormalities. Until recently, NVC was used in the diagnosis of SSc as well as in the assessment and follow-up of peripheral digital vasculopathy. On the top of digital ulcers, internal organ involvement such as myocardial dysfunction, pulmonary vascular and/or parenchymal lung disease characterizes severe SSc imparting a high risk of mortality. There is growing evidence suggesting that the extent of peripheral microvascular changes reflects the severity of the disease, especially in terms of life-threatening cardiopulmonary complications. The possible use of nailfold videocapillaroscopy as a useful, non-invasive modality to improve the ability to identify patients at higher risk for these devastating complications of the disease remains to be established.The aim of this review is to critically summarize and discuss current literature regarding the relationship between morphological alterations of nailfold dermal papillary vessels and several manifestations of SSc, focusing on visceral organ involvement, as well as their association with surrogate markers of macrovascular disease.
http://ift.tt/2rn8x5y
Can ARFI elastography be used to differentiate parathyroid from thyroid lesions?
Abstract
Objectives
To assess if elasticity score (ES) and shear wave velocity (SWV) measurement obtained using ARFI elastography can differentiate between parathyroid lesions and thyroid nodules.
Materials and methods
ARFI elastography was performed on patients with primary hyperparathyroidism or solid thyroid nodules who were being considered for surgery using virtual touch quantification and virtual touch imaging (VTI) software. Only patients with surgical histopathology (47 parathyroid lesions, 38 benign thyroid nodules and 55 malignant thyroid nodules) were included for final analysis. SWV and ES of the parathyroid and thyroid nodules were compared and their ability to differentiate between parathyroid and thyroid was analyzed using receiver operating characteristic curve analysis.
Results
There were 39 solitary adenomas, 2 double adenomas and 4 parathyroid hyperplasias with mean size of 19.6 ± 9.7 mm in 44 patients (21 male, 23 females) with primary hyperparathyroidism. The mean SWV of the parathyroid lesion (1.6 ± 0.78 m/s) was significantly different from benign (2.11 ± 0.8 m/s) and malignant (4.3 ± 2.71 m/s) thyroid nodules, p < 0.05; so was the ES, Chi square = 51.6, p < 0.001. The majority of parathyroid lesions (n = 37, 78.7%) had ES of 2 with speckled (n = 42, 89.3%) appearance, and none showed ES of 4. The diagnostic performance of speckled appearance on VTI, elasticity score and SWV measurements was 0.901, 0.724 and 0.797, respectively, to differentiate between parathyroid and thyroid lesions.
Conclusions
Parathyroid lesions are softer than thyroid nodules. A shear wave velocity of 1.72 m/s can differentiate between parathyroid lesions and thyroid nodules.
http://ift.tt/2rni7oY
Head and neck cancer cell radiosensitization upon dual targeting of c-Abl and beta1-integrin
Source:Radiotherapy and Oncology
Author(s): Philipp Koppenhagen, Ellen Dickreuter, Nils Cordes
Integrin-mediated cell adhesion to extracellular matrix (ECM) critically contributes to cancer cell therapy resistance and DNA double strand break (DSB) repair. c-Abl tyrosine kinase has been linked to both of these processes. Based on our previous findings indicating c-Abl hyperphosphorylation on tyrosine (Y) 412 and threonine (T) 735 upon beta1-integrin inhibition, we hypothesized c-Abl tyrosine kinase as an important mediator of beta1-integrin signaling for radioresistance. In a panel of 8 cell lines from different solid cancer types grown in 3D laminin-rich ECM cultures, we targeted beta1 integrin with AIIB2 (mAb) and c-Abl with Imatinib with and without X-ray irradiation and subsequently examined clonogenic survival, residual DSBs, protein expression and phosphorylation. Single or combined treatment with AIIB2 and Imatinib resulted in cell line-dependent cytotoxicity. Intriguingly, we identified a subgroup of this cell line panel that responded with a higher degree of radiosensitization to AIIB2/Imatinib relative to both single treatments. In this subgroup, we observed a non-statistically significant trend between the radioresponse and phospho-c-Abl Y412. Mechanistically, impairment of DNA repair seems to be associated with radiosensitization upon AIIB2/Imatinib and AIIB2/Imatinib-related radiosensitization could be reduced by exogenous overexpression of either wildtype or constitutively active c-Abl forms relative to controls. Our data generated in more physiological 3D cancer cell culture models suggest c-Abl as further determinant of radioresistance and DNA repair downstream of beta1-integrin. For solid cancers, c-Abl phosphorylation status might be an indicator for reasonable Imatinib application as adjuvant for conventional radio(chemo)therapy.
http://ift.tt/2rnlcFJ
Fast and slow Ca2+-dependent hyperpolarization mechanisms connect membrane potential and sleep homeostasis
Source:Current Opinion in Neurobiology, Volume 44
Author(s): Koji L Ode, Takahiro Katsumata, Daisuke Tone, Hiroki R Ueda
Several lines of evidence indicate that the sleep-wake state of cortical neurons is regulated not only through neuronal projections from the lower brain, but also through the cortical neurons' intrinsic ability to initiate a slow firing pattern related to the slow-wave oscillation observed in electroencephalography of the sleeping brain. Theoretical modeling and experiments with genetic and pharmacological perturbation suggest that ion channels and kinases acting downstream of calcium signaling regulate the cortical-membrane potential and sleep duration. In this review, we introduce possible Ca2+-dependent hyperpolarization mechanisms in cortical neurons, in which Ca2+ signaling associated with neuronal excitation evokes kinase cascades, and the activated kinases modify ion channels or pumps to regulate the cortical sleep/wake firing mode.
http://ift.tt/2qETgZC
Sleep homeostasis, habits and habituation
Publication date: June 2017
Source:Current Opinion in Neurobiology, Volume 44
Author(s): Vladyslav V Vyazovskiy, Mark E Walton, Stuart N Peirson, David M Bannerman
The importance of sleep for behavioural performance during waking is long-established, but the underlying reasons and mechanisms remain elusive. Waking and sleep are associated with changes in the levels of GluA1 AMPAR subunit in synaptic membranes, while studies using genetically-modified mice have identified an important role for GluA1-dependent synaptic plasticity in a non-associative form of memory that underlies short-term habituation to recently experienced stimuli. Here we posit that sleep may play a role in dishabituation, which restores attentional capacity and maximises the readiness of the animal for learning and goal-directed behaviour during subsequent wakefulness. Furthermore we suggest that sleep disturbance may fundamentally change the nature of behaviour, making it more model-free and habitual as a result of reduced attentional capacity.
http://ift.tt/2rarLuM
Local aspects of sleep and wakefulness
Source:Current Opinion in Neurobiology, Volume 44
Author(s): Francesca Siclari, Giulio Tononi
Slow waves, the hallmark of NREM (Non Rapid Eye Movement) sleep, are not uniformly distributed across the cortical surface, but can occur locally and asynchronously across brain regions. Their regional distribution and amplitude is affected by brain maturation and by time spent awake, mediated in part by experience-dependent changes in synaptic strength. Recent studies have shown that local low-frequency oscillations (<10Hz) can also occur in REM sleep and during wakefulness, leading to region-specific cognitive errors. Local decreases and increases of slow wave activity in posterior brain regions have been linked to the occurrence of dreaming and to unconscious sleep, respectively. Finally, the coexistence of local sleep-like and wake-like patterns in different brain areas is characteristic of several sleep disorders and may offer insights into these conditions.
http://ift.tt/2qFcoHb
Robotic resistance treadmill training improves locomotor function in children with cerebral palsy: a randomized controlled pilot study
Source:Archives of Physical Medicine and Rehabilitation
Author(s): Ming Wu, Janis Kim, Deborah J. Gaebler-Spira, Brian D. Schmit, Pooja Arora
ObjectiveTo determine whether applying controlled resistance forces to the legs during the swing phase of gait may improve the efficacy of treadmill training compared to applying controlled assistance forces in children with cerebral palsy (CP).DesignRandomized controlled study.SettingResearch unit of rehabilitation hospital.ParticipantsChildren with spastic CP (n = 23, average age 10.6 years old, ranged from 6-14, GMFCS levels: I to IV).InterventionsParticipants were randomly assigned to receive controlled assistance (n=11) or resistance (n=12) loads applied to the legs at the ankle. Participants underwent robotic treadmill training 3 times a week for 6 weeks (18 sessions). A controlled swing assistance/resistance load was applied to both legs starting from toe-off to mid-swing phase of gait during training.Main outcome measuresOutcome measures consisted of overground walking speed, 6 minute walking distance, and GMFM scores, and were assessed pre, post 6 weeks of training, and 8 weeks after the end of training.ResultsFollowing 6 weeks of treadmill training for participants from the resistance training group, fast walking speed and 6 minute walking distance significantly improved (18% and 30% increases, respectively), and 6 minute walking distance was still significantly greater than baseline (35% increase) 8 weeks after the end of training. In contrast, overground gait speed and 6 minute walking distance had no significant changes after robotic assistance training.ConclusionResults from the current study indicated that robotic resistance treadmill training is more effective than assistance training in improving locomotor function in children with CP.
http://ift.tt/2sd3geM
Low-intensity laser therapy efficacy evaluation in FVB mice subjected to acute and chronic arthritis
Abstract
Rheumatoid arthritis, an autoimmune inflammation, has a high prevalence in the population, and while therapy is available, it required often injection of drugs causing discomfort to patients. This study evaluates the clinical and histological effect of low-intensity laser therapy (LILT) as an alternative treatment, in a murine model of acute and chronic inflammation. FVB mice received either a Zymosan A injection into one knee joint inducing acute inflammation, followed after 15 min or 24 h by LILT or a collagen bovine type II injection emulsified in "Freund's Complete Adjuvant" to induce chronic arthritis, followed at 4 weeks with multiple LILT sessions. LILT mediated by either 660, 808, or 905 nm and tissue response was evaluated based on clinical symptoms and histological analysis of inflammatory infiltrate and damage to the articular surfaces. LILT can be effective in elevating clinical symptoms, so Kruskal-Wallis testing indicated no significant differences between knees affected by acute arthritis and treated once with LILT and an injured knee without treatment (p > 0.05) for 660 and 808 nm with some improvements for the 905-nm LILT. Mice receiving two treatments for acute arthritis showed exacerbation of inflammation and articular resorption following therapy with a 660-nm continuous laser (p < 0.05). For chronic inflammation, differences were not noted between LILT treated and untreated injured knee joints (p > 0.05). Among the lasers, the 905 nm tends to show better results for anti-inflammatory effect in acute arthritis, and the 660 nm showed better results in chronic arthritis. In conclusion, LILT wavelength selection depends on the arthritis condition and can demonstrate anti-inflammatory effects for chronic arthritis and reduced resorption area in this murine model.
http://ift.tt/2rj2A7F
Tuning the functionalization degree of amylose and amylopectin with photochromic spiropyran by CuAAc reaction
Publication date: 30 June 2017
Source:Polymer, Volume 120
Author(s): David Barsi, Silvia Borsacchi, Lucia Calucci, Antonio Tarantino, Calogero Pinzino, Monica Bertoldo
Amylose and amylopectin were functionalized with an alkynyl derivative of spiropyran (SPCC) and/or propargyl alcohol by a two step procedure consisting in the derivatization of glucopyranose units with azide at the C6 position followed by Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAc). Substitution degrees with spiropyran (DSSP) between 0.10 and 0.95 were achieved by simply modulating the molar ratio between alkyne species and polysaccharide in the CuAAc reaction, as it was confirmed by FT-IR and NMR spectroscopy characterizations. The UV–Vis spectra of SPCC-modified amylose in DMF solution kept in the dark exhibited an absorbance band with maximum at ∼346 nm, ascribed to spiropyran units. The intensity of the absorbance was found to increase linearly with DSSP. Upon irradiation with UV light, a band at ∼560 nm appeared, due to the conversion of spiropyran to zwitterionic merocyanine, its intensity linearly increasing with DSSP too. ICP-MS analysis showed the presence of a small amount (<270 ppm) of residual Cu from the catalyst in the functionalized polysaccharides. However, EPR spectroscopy indicated that Cu2+ species are bonded to different moieties and they do not significantly interfere with the optical behaviour. These findings indicate that the proposed synthetic strategy can be exploited to prepare photochromic materials with the desired signal intensity by using natural amylose as raw material.
Graphical abstract
http://ift.tt/2qEY2Xj
Stationary crack propagation in a two-dimensional visco-elastic network model
Publication date: 30 June 2017
Source:Polymer, Volume 120
Author(s): Yuko Aoyanagi, Ko Okumura
We investigate crack propagation in a simple two-dimensional visco-elastic model and find a scaling regime in the relation between the propagation velocity and energy release rate or fracture energy, together with lower and upper bounds of the scaling regime. On the basis of our result, the existence of the lower and upper bounds is expected to be universal or model-independent: the present simple simulation model provides generic insight into the physics of crack propagation, and the model will be a first step towards the development of a more refined coarse-grained model. Relatively abrupt changes of velocity are predicted near the lower and upper bounds for the scaling regime and the positions of the bounds could be good markers for the development of tough polymers, for which we provide simple views that could be useful as guiding principles for toughening polymer-based materials.
Graphical abstract
http://ift.tt/2qEUOTD
Internalization and localization of basal insulin peglispro in cells
Source:Molecular and Cellular Endocrinology
Author(s): Julie S. Moyers, Catherine B. Volk, Julia X.C. Cao, Chen Zhang, Liyun Ding, Vladislav V. Kiselyov, M. Dodson Michael
BackgroundBasal insulin peglispro (BIL) is a novel, PEGylated insulin lispro that has a large hydrodynamic size compared with insulin lispro. It has a prolonged duration of action, which is related to a delay in insulin absorption and a reduction in clearance. Given the different physical properties of BIL compared with native insulin and insulin lispro, it is important to assess the cellular internalization characteristics of the molecule.Methods and materialsUsing immunofluorescent confocal imaging, we compared the cellular internalization and localization patterns of BIL, biosynthetic human insulin, and insulin lispro. We assessed the effects of BIL on internalization of the insulin receptor (IR) and studied cellular clearance of radio-labeled BIL.ResultsCo-localization studies using antibodies to either insulin or PEG, and the early endosomal marker EEA1 showed that the overall internalization and subcellular localization pattern of BIL was similar to that of human insulin and insulin lispro; all were rapidly internalized and co-localized with EEA1. During ligand washout for 4 h, concomitant loss of insulin, PEG methoxy group, and PEG backbone immunostaining was observed for BIL, similar to the loss of insulin immunostaining observed for insulin lispro and human insulin. Co-localization studies using an antibody to the lysosomal marker LAMP1 did not reveal evidence of lysosomal localization for insulin lispro, human insulin, BIL, or PEG using either insulin or PEG immunostaining reagents. BIL and human insulin both induced rapid phosphorylation and internalization of human IR.ConclusionsOur findings show that treatment of cells with BIL stimulates internalization and localization of IR to early endosomes. Both the insulin and PEG moieties of BIL undergo a dynamic cellular process of rapid internalization and transport to early endosomes followed by loss of cellular immunostaining in a manner similar to that of insulin lispro and human insulin. The rate of clearance for the insulin lispro portion of BIL was slower than the rate of clearance for human insulin. In contrast, the PEG moiety of BIL can recycle out of cells.
http://ift.tt/2qyZhMi
Sciadopitysin suppresses RANKL-mediated osteoclastogenesis and prevents bone loss in LPS-treated mice
Publication date: August 2017
Source:International Immunopharmacology, Volume 49
Author(s): Jinjin Cao, Qiang Lu, Ning Liu, Yu-xin Zhang, Jing Wang, Maolin Zhang, Hong-bing Wang, Wan-chun Sun
Previous studies reported that sciadopitysin (Sc), a type of biflavonoids, protects reactive oxygen species (ROS)-mediated osteoblast dysfunction, but its role in osteoclastogenesis remains unclear. In this study, we observed that Sc dose-dependently suppressed RANKL-induced osteoclastogenesis and bone resorption. Our results indicated that Sc treatment strongly reduced RANKL-induced osteoclast-specific genes expression, including cathepsin K (CTSK), tartrate-resistant acid phosphatase (TRAP) and MMP-9. Furthermore, Sc apparently attenuated RANKL-increased expressions of c-Fos and NFATc1. Meanwhile, Sc also strikingly inhibited the activation of NF-κB without altering the phosphorylation of MAPKs (p38, JNK and ERK1/2). Finally, our study demonstrated that Sc administration could reverse the bone loss in LPS-induced mice model. This study suggests that Sc inhibits RANKL-induced osteoclastogenesis and bone loss by inhibiting NF-κB activation and reducing the expression of c-Fos and NFATc1. Therefore, Sc might be benefit for RANKL-mediated osteolytic bone diseases.
http://ift.tt/2rj1bOp
Association of LTBR polymorphisms with chronic hepatitis B virus infection and hepatitis B virus-related hepatocellular carcinoma
Publication date: August 2017
Source:International Immunopharmacology, Volume 49
Author(s): Qianqian Zhu, Na Li, Fang Li, Jiao Sang, Huan Deng, Qunying Han, Yi Lv, Chunyan Li, Zhengwen Liu
Lymphotoxin-β receptor (LTβR) signaling is involved in hepatitis B virus (HBV) infection, hepatitis and liver carcinogenesis. However, the potential association between LTBR polymorphisms and HBV infection remains unclear. This study investigated the associations between LTBR polymorphisms and chronic HBV infection and HBV-related hepatocellular carcinoma (HCC). The study included 409 patients with chronic HBV infection, 73 HBV infection resolvers, and 197 healthy controls. Two polymorphisms rs12354 and rs3759333 were selected and genotyped by polymerase chain reaction-ligase detection reaction method. The frequencies of rs12354 genotype GT and allele T in HBV infection resolvers were significantly higher than those in patients with chronic HBV infection and healthy controls (genotype GT: 38.4% vs. 22.2% and 38.4% vs. 20.8%, P=0.004 and P=0.004, respectively; allele T: 20.5% vs. 13.1% and 20.5% vs. 12.9%, P=0.017 and P=0.028, respectively). The frequencies of rs3759333 genotypes and alleles between HBV patients, HBV infection resolvers and healthy controls had no statistical difference. The genotype and allele frequencies of rs12354 and rs3759333 had no statistical differences between chronic hepatitis B and HBV-related HCC patients. The serum LTβR levels and the overall survival rate between HBV-related HCC patients carrying different rs12354 and rs3759333 genotypes had no statistical differences. These results suggest that the LTBR rs12354 polymorphism might be associated with the spontaneous resolution of HBV infection. Additional studies with large sample size are needed to confirm and extend these findings.
http://ift.tt/2qywMys
Schisandrin B inhibits LPS-induced inflammatory response in human umbilical vein endothelial cells by activating Nrf2
Publication date: August 2017
Source:International Immunopharmacology, Volume 49
Author(s): Qiuning Lin, Xiao Qin, Mei Shi, Zhong Qin, Yuanbiao Meng, Zhongyu Qin, Sien Guo
Schisandrin B (SchB), an active ingredient extracted from Schisandra chinensis (Turcz.) Baill, has been known to have anti-oxidant and anti-inflammatory activities. In this study, we investigated the anti-inflammatory effects and mechanism of SchB in LPS-stimulated human umbilical vein endothelial cells (HUVECs). The effects of SchB on VCAM-1, ICAM-1, NF-κB and Nrf2 expression were detected by western blot analysis. The effects of SchB on TNF-α and IL-8 production were detected by ELISA. The results showed that SchB strongly suppressed the production of TNF-α and IL-8 in HUVECs stimulated with LPS. SchB also inhibited LPS-induced VCAM-1 and ICAM-1 expression. Furthermore, SchB blocked the activation of NF-κB induced by LPS. In addition, SchB increased the expression of Nrf2 and HO-1 in a concentration-dependent manner. And the inhibition of TNF-α and IL-8 production by SchB was blocked by transfection with Nrf2 siRNA. Our findings showed that SchB inhibited LPS-induced inflammation in HUVECs by activating Nrf2 signaling pathway.
http://ift.tt/2riO67G
Τρίτη 30 Μαΐου 2017
Podcast Interviews
ATA Members give podcast interviews on Thyroid Topics at www.docthyroid.com
Información Importante Sobre los Nódulos Tiroideos con la Dra Regina Castro de la Clínica Mayo
Interviewed and produced by Philip James | May 4, 2017 | Endocrine, Pathology, Podcast
You Have a Thyroid Nodule, What Happens Next? with Dr. Regina Castro from The Mayo Clinic
Interviewed and produced by Philip James | Apr 2, 2017 | Pathology, Podcast, Surgery
The post Podcast Interviews appeared first on American Thyroid Association.
http://ift.tt/2scqYry
Structural Basis for Regulation of ESCRT-III Complexes by Lgd
Publication date: 30 May 2017
Source:Cell Reports, Volume 19, Issue 9
Author(s): Brian J. McMillan, Christine Tibbe, Andrew A. Drabek, Tom C.M. Seegar, Stephen C. Blacklow, Thomas Klein
The ESCRT-III complex induces outward membrane budding and fission through homotypic polymerization of its core component Shrub/CHMP4B. Shrub activity is regulated by its direct interaction with a protein called Lgd in flies, or CC2D1A or B in humans. Here, we report the structural basis for this interaction and propose a mechanism for regulation of polymer assembly. The isolated third DM14 repeat of Lgd binds Shrub, and an Lgd fragment containing only this DM14 repeat and its C-terminal C2 domain is sufficient for in vivo function. The DM14 domain forms a helical hairpin with a conserved, positively charged tip, that, in the structure of a DM14 domain-Shrub complex, occupies a negatively charged surface of Shrub that is otherwise used for homopolymerization. Lgd mutations at this interface disrupt its function in flies, confirming functional importance. Together, these data argue that Lgd regulates ESCRT activity by controlling access to the Shrub self-assembly surface.
Graphical abstract
Teaser
Shrub is a Drosophila ESCRT-III protein that self-associates to promote membrane budding and fission. Its activity is modulated by binding to Lgd, which suppresses self-association. McMillan et al. report the structural basis for masking of the Shrub self-association surface of Shrub by Lgd, which, together with functional studies in flies, suggests models for modulation of Shrub activity by Lgd.http://ift.tt/2rCQTLO
The Histone Variant MacroH2A1 Is a BRCA1 Ubiquitin Ligase Substrate
Publication date: 30 May 2017
Source:Cell Reports, Volume 19, Issue 9
Author(s): Beom-Jun Kim, Doug W. Chan, Sung Yun Jung, Yue Chen, Jun Qin, Yi Wang
The breast- and ovarian-cancer-specific tumor suppressor BRCA1 and its heterodimeric partner BARD1 contain RING domains that implicate them as E3 ubiquitin ligases. Despite extensive efforts, the bona fide substrates of BRCA1/BARD1 remain elusive. Here, we used recombinant GST fused to four UBA domains to enrich ubiquitinated proteins followed by a Lys-ε-Gly-Gly (diGly) antibody to enrich ubiquitinated tryptic peptides. This tandem affinity purification method coupled with mass spectrometry identified 101 putative BRCA1/BARD1 E3 substrates. We identified the histone variant macroH2A1 from the screen and showed that BRCA1/BARD1 ubiquitinates macroH2A1 at lysine 123 in vitro and in vivo. Primary human fibroblasts stably expressing a ubiquitination-deficient macroH2A1 mutant were defective in cellular senescence compared to their wild-type counterpart. Our study demonstrates that BRCA1/BARD1 is a macroH2A1 E3 ligase and implicates a role for macroH2A1 K123 ubiquitination in cellular senescence.
Graphical abstract
Teaser
Using a tandem affinity purification method coupled with mass spectrometry, Kim et al. identified 101 putative substrates of the BRCA1/BARD1 E3 ubiquitin ligase. They report that, among these substrates, ubiquitination at Lys123 of macroH2A1 plays an important role in replicative senescence.http://ift.tt/2rDwPce
-
Publication date: September 2017 Source: Free Radical Biology and Medicine, Volume 110 Author(s): Lucía Fernández-del-Río, Anish Nag, Elen...
-
Abstract Noise pollution is a major factor of environmental complaints in many cities, which has significant impacts on human health. As a...
