Σάββατο 21 Απριλίου 2018
Scholar : West China Journal of Stomatology, Year 2018, Issue 01 -New Issue Alert.
Scholar : Chinese Journal of Otorhinolaryngology Head and Neck Surgery, Year 2018, Issue 02 -New Issue Alert.
|
Nanomechanics and ultrastructure of the internal mammary artery adventitia in patients with low and high pulse wave velocity
Publication date: Available online 21 April 2018
Source:Acta Biomaterialia
Author(s): Zhuo Chang, Paolo Paoletti, Steve D. Barrett, Ya Hua Chim, Eva Caamaño-Gutiérrez, Maria Lyck Hansen, Hans Christian Beck, Lars Melholt Rasmussen, Riaz Akhtar
The collagen-rich adventitia is the outermost arterial layer and plays an important biomechanical and physiological role in normal vessel function. While there has been a lot of effort to understand the role of the medial layer on arterial biomechanics, the adventitia has received less attention. In this study, we hypothesized that different ultrastructural and nanomechanical properties would be exhibited in the adventitia of the internal mammary artery (IMA) in patients with a low degree of arterial stiffening as compared to those with a high degree of arterial stiffening. Human IMA biopsies were obtained from a cohort of patients with arterial stiffening assessed via carotid-femoral PWV. Patients were grouped as low PWV (8.5±0.7 ms-1, n=8) and high PWV (13.4±3.0 ms-1, n=9). Peakforce QNM Atomic force microscopy (AFM) was used to determine the nanomechanical and morphological properties of the IMA. The nano-scale elastic modulus was found to correlate with PWV. We show for the first time that nano-scale alterations in adventitial collagen fibrils in the IMA are evident in patients with high PWV, even though the IMA is not involved in the carotid-femoral pathway. Our approach provides new insight into systemic structure-property changes in the vasculature, and also provides a method of characterizing small biopsy samples to predict the development of arterial stiffening.STATEMENT OF SIGNIFICANCEArterial stiffening occurs as part of the natural aging process and is strongly linked to cardiovascular risk. Although arterial stiffening is routinely measured in vivo, little is known about how localised changes in artery structure and biomechanics contributes to in vivo arterial stiffening. This study focusses on the role of the outermost layer of arteries, the adventitia, in arterial stiffening. The study provides data on nano-scale changes in collagen fibril structure and mechanical properties in the adventitia and shows how it relates to in vivo stiffness measurements in the vascular system. This is the first study to link in vivo arterial stiffening with nanomechanical changes artery biopsy samples. Hence, this approach could be used to develop new diagnostic methods for vascular disease.
Graphical abstract
https://ift.tt/2Jhh9Ah
Multi-Scale Structural Design and Biomechanics of the Pistol Shrimp Snapper Claw
Publication date: Available online 21 April 2018
Source:Acta Biomaterialia
Author(s): Shahrouz Amini, Maryam Tadayon, J.Q. Isaiah Chua, Ali Miserez
The Arthropoda, the largest phylum of the Animal Kingdom, have successfully evolved to survive various ecological constraints under a wide range of environmental conditions. Central to this survival are the structural designs developed in their exoskeletons and their raptorial appendages for protection and hunting. One such example, the pistol shrimp, is a shallow-water crustacean that is well-known for its aggressive hunting behavior, using its snapper claw to trigger the nucleation of cavitation bubbles that strike targets. In this study, we conducted a multi-scale structural/nanomechanics relationship study of this biotool to analyze its mechanical response to contact stresses. We found that the pistol shrimp snapper claw, which exhibits the capacity to emit a high-velocity water jet during rapid closure actions, is more brittle than other mineralized biotools, with accelerated wear damage under contact stresses. However, due to an angular offset between the dactylus and pollex of the snapper claw, the appendage never engages in any mechanical contact during the snapping action. This feature is in stark contrast to that reported in other fast raptorial appendages of crustaceans, notably the mantis shrimp dactyl club, which is designed to shatter close range targets in contact mode and exhibits a superior resistance to contact damages and wear. These findings suggest that adaptation of hunting appendages goes beyond their macroscopic morphology, and that multi-scale structural design concomitantly adapted to function, with enhanced structural complexification for tools that are subjected to more intense contact stresses.Statement of SignificanceThe evolution success of crustaceans is largely due to the diversification of their mineralized exoskeletons and hunting appendages, which exhibit a large palette of morphometric characteristics that have adapted to meet particular functions. We explored the "snapper claw" of the pistol shrimp, which is used to generate cavitation bubbles and strike prey. Our multi-scale structure-property relationship study reveals that the snapper claw is more brittle than other fast raptorial appendages –such as the stomatopod dactyl club– because it is not directly subjected to direct contact forces during action. This study implies that when higher mechanical stresses are needed to meet the function, the internal structure is built of a more complex architecture that allows to mitigate internal structural damage.
Graphical abstract
https://ift.tt/2HHMjDR
Injectable drug depot engineered to release multiple ophthalmic therapeutic agents with precise time profiles for postoperative treatment following ocular surgery
Publication date: Available online 21 April 2018
Source:Acta Biomaterialia
Author(s): Maziar Mohammadi, Kisha Patel, Seyedeh P. Alaie, Ron B. Shmueli, Cagri G. Besirli, Ronald G. Larson, Jordan J. Green
A multi-drug delivery platform is developed to address current shortcomings of post-operative ocular drug delivery. The sustained biodegradable drug release system is composed of biodegradable polymeric microparticles (MPs) incorporated into a bulk biodegradable hydrogel made from triblock copolymers with poly(ethylene glycol) (PEG) center blocks and hydrophobic biodegradable polyester blocks such as poly(lactide-co-glycolide) (PLGA), Poly(lactic acid) (PLA), or Poly(lactide-co-caprolactone) (PLCL) blocks. This system is engineered to flow as a liquid solution at room temperature for facile injection into the eye and then quickly gel as it warms to physiological body temperatures (approximately 37 °C). The hydrogel acts as an ocular depot that can release three different drug molecules at programmed rates and times to provide optimal release of each species. In this manuscript, the hydrogel is configured to release a broad-spectrum antibiotic, a potent corticosteroid, and an ocular hypotensive, three ophthalmic therapeutic agents that are essential for post-operative management after ocular surgery, each drug released at its own timescale. The delivery platform is designed to mimic current topical application of postoperative ocular formulations, releasing the antibiotic for up to a week, and the corticosteroid and the ocular hypotensive agents for at least a month. Hydrophobic blocks, such as PLCL, were utilized to prolong the release duration of the biomolecules. This system also enables customization by being able to vary the initial drug loading to linearly tune the drug dose released, while maintaining a constant drug release profile over time. This minimally invasive biodegradable multi-drug delivery system is capable of replacing a complex ocular treatment regimen with a simple injection. Such a depot system has the potential to increase patient medication compliance and reduce both the immediate and late term complications following ophthalmic surgery.Statement of SignificanceAfter ocular surgery, patients routinely receive multiple medications including antibiotics, steroids and ocular hypotensives to ensure optimal surgical outcomes. The current standard of care for postoperative treatment after ocular surgery involves using eye drops daily, which has limited effectiveness mainly due to poor patient adherence. To improve patient experience and outcomes, this article presents the first thermoresponsive hydrogel able to release multiple drug molecules for the application of post-operative treatment following ocular surgery. By varying the parameters such as hydrogel type and polymer hydrophobicity, the drug release profile, duration and dosage can finely be tuned. The approach presented in this article can readily be applied to other applications by simply changing the drug loaded in the drug delivery system.
Graphical abstract
https://ift.tt/2HiJ421
Component effect of stem cell-loaded thermosensitive polypeptide hydrogels on cartilage repair
Publication date: Available online 21 April 2018
Source:Acta Biomaterialia
Author(s): He Liu, Yilong Cheng, Jinjin Chen, Fei Chang, Jincheng Wang, Jianxun Ding, Xuesi Chen
Biophysical properties of the desired biomimetic scaffolds, such as porosity and elasticity, have been proven associated with the efficacy of cartilage regeneration. In this work, the copolymers of poly(L-alanine)-block-poly(ethylene glycol)-block-poly(L-alanine) (PA-PEG-PA) and poly(L-alanine-co-L-phenylalanine)-block-poly(ethylene glycol)-block-poly(L-alanine-co-L-phenylalanine) (PAF-PEG-PAF) with different ratios of alanine to phenylalanine were synthesized. The introduction of a hydrophobic amino acid, phenylalanine, into polyalanine-based thermosensitive hydrogel leaded to the enhanced gelation behaviors and upregulated mechanical properties. Moreover, the increase of phenylalanine content resulted in the enlarged pore size and enhanced mechanical strength of PAF-PEG-PAF thermogel, followed by the regeneration of hyaline-like cartilage with reduced fibrous tissue formation. The findings indicated the great potential of thermosensitive polypeptide hydrogels in cartilage tissue engineering.Statement of SignificanceArticular cartilage defect has limited self-repair ability due to the lack of blood supply and innervation, which may lead to knee osteoarthritis afterwards. Injectable hydrogels are demonstrated possessing outstanding properties as biomimetic scaffolds in cartilage tissue engineering, while the effect of biophysical properties on the efficacy of cartilage regeneration has not been revealed. Herein, the poly(ethylene glycol)−polypeptide triblock copolymers with different ratios of alanine to phenylalanine were synthesized. The sol-to-gel transition temperature and the critical gelling concentration decreased as the increased amount of phenylalanine units, resulting in the enlarged pore size and enhanced mechanical strength. These features lead to better regeneration of hyaline-like cartilage with reduced fibrous tissue formation, indicating great potential of thermosensitive polypeptide hydrogels for efficient cartilage repair.
Graphical abstract
https://ift.tt/2HFzee8
Decoration of RGD-mimetic Porous Scaffolds with Engineered and Devitalized Extracellular Matrix for Adipose Tissue Regeneration
Publication date: Available online 21 April 2018
Source:Acta Biomaterialia
Author(s): Eleonora Rossi, Julien Guerrero, Paola Aprile, Alessandro Tocchio, Elisabeth A Kappos, Cristina Lenardi, Ivan Martin, Arnaud Scherberich
Fat grafting is emerging as a promising alternative to silicon implants in breast reconstruction surgery. Unfortunately, this approach does not provide a proper mechanical support and is affected by drawbacks such as tissue resorption and donor site morbidity. Synthetic scaffolds can offer a valuable alternative to address these challenges, but poorly recapitulate the biochemical stimuli needed for tissue regeneration. Here, we aim at combining the positive features of a structural, synthetic polymer to an engineered, devitalized extracellular matrix (ECM) to generate a hybrid construct that can provide a mix of structural and biological stimuli needed for adipose tissue regeneration. A RGD-mimetic synthetic scaffold OPAAF, designed for soft tissue engineering, was decorated with ECM deposited by human adipose stromal cells (hASCs). The adipoinductive potential of the hybrid ECM-OPAAF construct was validated in vitro, by culture with hASC in a perfusion bioreactor system, and in vivo, by subcutaneous implantation in nude mouse. Our findings demonstrate that the hybrid ECM-OPAAF provides proper mechanical support and adipoinductive stimuli, with potential applicability as off-the-shelf material for adipose tissue reconstruction.Statement of significanceIn this study we combined the functionalities of a synthetic polymer with those of an engineered and subsequently devitalized extracellular matrix (ECM) to generate a hybrid material for adipose tissue regeneration. The developed hybrid ECM-OPAAF was demonstrated to regulate human adipose stromal cells adipogenic commitment in vitro and adipose tissue infiltration in vivo. Our findings demonstrate that the hybrid ECM-OPAAF provide proper mechanical support and adipoinductive stimuli and represents a promising off-the-shelf material for adipose tissue reconstruction.We believe that our approach could offer an alternative strategy for adipose tissue reconstruction incase of mastectomy or congenital abnormalities, overcoming the current limitations of autologous fat based strategies such as volume resorption and donor site morbidity.
Graphical abstract
https://ift.tt/2qMYaaa
Using a gradient boosting model to improve the performance of low-cost aerosol monitors in a dense, heterogeneous urban environment
Publication date: July 2018
Source:Atmospheric Environment, Volume 184
Author(s): Nicholas E. Johnson, Bartosz Bonczak, Constantine E. Kontokosta
The increased availability and improved quality of new sensing technologies have catalyzed a growing body of research to evaluate and leverage these tools in order to quantify and describe urban environments. Air quality, in particular, has received greater attention because of the well-established links to serious respiratory illnesses and the unprecedented levels of air pollution in developed and developing countries and cities around the world. Though numerous laboratory and field evaluation studies have begun to explore the use and potential of low-cost air quality monitoring devices, the performance and stability of these tools has not been adequately evaluated in complex urban environments, and further research is needed. In this study, we present the design of a low-cost air quality monitoring platform based on the Shinyei PPD42 aerosol monitor and examine the suitability of the sensor for deployment in a dense heterogeneous urban environment. We assess the sensor's performance during a field calibration campaign from February 7th to March 25th 2017 with a reference instrument in New York City, and present a novel calibration approach using a machine learning method that incorporates publicly available meteorological data in order to improve overall sensor performance. We find that while the PPD42 performs well in relation to the reference instrument using linear regression (R2 = 0.36–0.51), a gradient boosting regression tree model can significantly improve device calibration (R2 = 0.68–0.76). We discuss the sensor's performance and reliability when deployed in a dense, heterogeneous urban environment during a period of significant variation in weather conditions, and important considerations when using machine learning techniques to improve the performance of low-cost air quality monitors.
Graphical abstract
https://ift.tt/2HiGOYF
Secondary organic aerosol and ozone formation from photo-oxidation of unburned diesel fuel in a surrogate atmospheric environment
Source:Atmospheric Environment, Volume 184
Author(s): Weihua Li, David R. Cocker
Diesel fuel is a complex mixture of intermediate volatility organic compounds (IVOCs). Previous studies focused on secondary organic aerosol (SOA) and ozone formation from photo-oxidation of organic vapor from diesel exhaust and their components such as aromatics and heavy alkanes. However, there are few studies on atmospheric behavior of unburnt diesel. Therefore, in this study, ten unburnt #2 commercial diesel samples and one FACE9A research diesel fuel were photo-oxidized in the University of California Riverside, College of Engineering-Center for Environmental Research & Technology dual environmental chambers to investigate their SOA and ozone production potential. Photochemical aging rapidly produced significant SOA (yield ∼20.3–37.7%) in the presence of a surrogate reactive organic gas (ROG) mixture used to mimic urban atmospheric reactivity. SOA yields were consistent with n-Heptadecane yields under similar conditions. Doubling NOx concentrations within relevant urban concentration levels enhanced SOA formation by 33% and ozone formation by 48%. SOA formation in this study was approximately fourteen times higher than previously reported for very high NOx conditions. An SOA experiment designed to mimic the previous work achieved similar yields to the earlier work. SOA formed under urban relevant NOx concentrations were consistent with semi-volatile-oxygenated organic aerosol (SV-OOA) and underwent little further chemical processing once produced.
https://ift.tt/2HA2S4H
Emission characteristics of NOx, CO, NH3 and VOCs from gas-fired industrial boilers based on field measurements in Beijing city, China
Source:Atmospheric Environment, Volume 184
Author(s): Tao Yue, Xiang Gao, Jiajia Gao, Yali Tong, Kun Wang, Penglai Zuo, Xiaoxi Zhang, Li Tong, Chenlong Wang, Yifeng Xue
In the past decade, due to the management policies and coal combustion controls in Beijing, the consumption of natural gas has increased gradually. Nevertheless, the research on the emission characteristics of gaseous pollutants emitted from gas-fired industrial boilers, especially considering the influence of low nitrogen (low-NOx) retrofit policy of gas boilers, is scarcely. In this study, based on literature and field investigations, onsite measurements of NOx, CO, NH3 and VOCs (Volatile Organic Compounds) emissions from gas-fired industrial boilers as well as the key factors that affected the emission of gaseous pollutants were discussed. Category-specific emission factors (EFs) of NOx, CO, NH3 and VOCs were obtained from the field measurements of 1107 "low-NOx" retrofitted and unabated gas-fired industrial boilers. Our results showed that operating load and control measures were the two key factors affecting the formation of gaseous pollutants. The EFs of NOx (EFNOx) and CO (EFCO) of atmospheric combustion boilers (ACBs) were much higher than the EFs of chamber combustion boilers (CCBs). The total emissions of NOx, CO, NH3 and VOCs from gas-fired industrial boilers in Beijing in the year of 2015 were estimated at 10489.6 t, 3272.8 t, 196.4 t and 235.4 t, respectively. Alkanes, BTEX, oxygenated VOCs and non-reactive organic matter were the four main chemical components of VOCs. As for the spatial distributions, the emissions of NOx, CO, NH3 and VOCs from gas-fired industrial boilers in Beijing were predominantly concentrated in central six urban districts. In the future, more detailed investigation and field tests for all kinds of gas-fired industrial boilers are still greatly needed to achieve more reliable estimations of atmospheric pollutants from gas-fired industrial boilers.
https://ift.tt/2HiGMA1
Long-term systematic profiling of dust aerosol optical properties using the EOLE NTUA lidar system over Athens, Greece (2000–2016)
Publication date: June 2018
Source:Atmospheric Environment, Volume 183
Author(s): O. Soupiona, A. Papayannis, P. Kokkalis, M. Mylonaki, G. Tsaknakis, A. Argyrouli, S. Vratolis
We present a comprehensive analysis of the seasonal variability of the vertical profiles of the optical and geometrical properties of Saharan dust aerosols, observed in the height region between 1000 and 6000 m, over the city of Athens, Greece, from February 2000 to December 2016. These observations were performed by a multi-wavelength (355-387-532-1064 nm) Raman lidar system under cloud-free conditions. The statistical analysis (using aerosol monthly mean values) is based on nighttime vertical Raman measurements of range-resolved aerosol optical properties (backscatter and extinction coefficients, lidar ratio, Ångström exponent) at 355 nm (57 dust events during more than 80 measurement hours). We found that the number of dust events was highest in spring, summer, and early autumn periods and that during spring the dust layers were moved at higher altitudes (∼4500 m) than in other seasons. The number of the forecasted dusty days (on monthly basis) by the BSC-DREAM8b model compared to those of the performed lidar measurements were found to have a quite strong correlation (R2 = 0.81), with a maximum occurrence predicted for the spring season. In the worst case scenario, at least 50% of the model-forecasted dust events can be observed by lidar under cloudless skies over Athens. For the sampled dust plumes we found mean lidar ratios of 52 ± 13 sr at 355 nm in the height range 2000–4000 m a.s.l. Moreover, the dust layers had a mean thickness of 2497 ± 1026 m and a center of mass of 2699 ± 1017 m.An analysis performed regarding the air mass back-trajectories arriving over Athens revealed two main clusters: one pathway from south-west to north-east, with dust emission areas in Tunisia, Algeria and Libya and a second one from south, across the Mediterranean Sea with emission areas over Libya and the remaining part of Algeria and Tunisia. This clustering enabled us to differentiate between the aerosol optical properties between the two clusters, based on their residence time over the Saharan region, the European continent and the Mediterranean Sea. We finally concluded that even if the dust source regions are about the same, the aging and mixing processes of these air masses, passing over different areas, might have an impact on the aerosol optical properties.
Graphical abstract
https://ift.tt/2HHIEpE
Variability in impact of air pollution on subjective well-being
Source:Atmospheric Environment, Volume 183
Author(s): Guodong Du, Kong Joo Shin, Shunsuke Managi
This paper examines the impact of variability in impact of air pollution on life satisfaction (LS). Previous studies have shown robust negative impact of air pollution on subjective well-being (SWB). However, empirical studies that consider variability in air pollution effects through comparative city study are limited. This study provides comparative evaluation of two major Chinese cities: Beijing and Shanghai. We apply a geo-statistical spatial interpolation technique on pollution data from monitoring sites to estimate the Sulfur Dioxide (SO2), Nitrogen Dioxide (NO2), coarse particles with a diameter between 2.5 and 10 μm (PM10) and fine particles with a diameter of 2.5 μm or less (PM2.5) pollution exposure of respondents of a survey conducted in 2016. The results show that all pollutants have robust negative impacts on LS for Beijing residents, whereas only SO2 and NO2 have significant negative impacts on LS for Shanghai residents; Per unit impact of SO2 is greater in Shanghai, and that of NO2 is greater in Beijing. Beijing and Shanghai residents have almost same monetary valuation for SO2 reduction but Beijing residents place approximately 1.5 times valuation on NO2 reduction compared to Shanghai residents. Moreover, the LS of Beijing residents is sensitive to temporal changes in the pollution level, whereas Shanghai residents are unaffected by such changes.
https://ift.tt/2Jhip6t
Meat allergy and allergens
Source:Molecular Immunology
Author(s): Jeffrey M. Wilson, Thomas A.E. Platts-Mills
IgE-mediated hypersensitivity to ingested animal products, including both mammalian and avian sources, is increasingly appreciated as an important form of food allergy. Traditionally described largely in children, it is now clear that allergy to meat (and animal viscera) impacts both children and adults and represents a heterogeneous group of allergic disorders with multiple distinct syndromes. The recognition of entities such as pork-cat syndrome and delayed anaphylaxis to red meat, i.e- the α-Gal syndrome, have shed light on fundamental, and in some cases newly appreciated, features of allergic disease. These include insights into routes of exposure and mechanisms of sensitization, as well as the realization that IgE-mediated reactions can be delayed by several hours. Here we review mammalian and avian meat allergy with an emphasis on the molecular allergens and pathways that contribute to disease, as well as the role of in vitro IgE testing in diagnosis and management.
https://ift.tt/2qPrKvo
Clinical Thyroidology®for the Public – Highlighted Article
From Clinical Thyroidology® for the Public: A patient survey of hypothyroid individuals demonstrates dissatisfaction with treatment and their managing physicians. Read More…
We welcome your feedback and suggestions. Let us know what you want to see in this publication.
Feedback & SuggestionsThe post Clinical Thyroidology<sup>®</sup>for the Public – Highlighted Article appeared first on American Thyroid Association.
https://ift.tt/2qQ3MiS
Seasonal and downstream alterations of dissolved organic matter and dissolved inorganic ions in a human-impacted mountainous tributary of the Yellow River, China
Abstract
Human activities impose important disturbances on both organic and inorganic chemistry in fluvial systems. In this study, we investigated the intra-annual and downstream variations of dissolved organic carbon (DOC), dissolved organic matter (DOM) excitation-emission matrix fluorescence (EEM) with parallel factor analysis (PARAFAC), major ions, and dissolved inorganic nitrogen (DIN) species in a mountainous tributary of the Yellow River, China. Both DOM quantity and quality, as represented by DOC and DOM fluorescence respectively, changed spatially and seasonally in the studied region. Fluorescence intensity of tryptophan-like components (C3) were found much higher at the populated downstream regions than in the undisturbed forested upstream regions. Seasonally, stronger fluorescence intensity of protein-like components (C3 and C4) was observed in the low-flow period (December) and in the medium-flow period (March) than in the high-flow period (May), particularly for the downstream reaches, reflecting the dominant impacts of wastewater pollution in the downstream regions. In contrast to the protein-like fluorescence, humic-like fluorescence components C1 and C2 exhibited distinctly higher intensity in the high-flow period with smaller spatial variation indicating strong flushing effect of increasing water discharge on terrestrial-sourced humic-like materials in the high-flow period. Pollution-affected dissolved inorganic ions, particularly Na+, Cl−, and NH4+-N, showed similar spatial and seasonal variations with protein-like fluorescence of DOM. The significant positive correlations between protein-like fluorescence of DOM and pollution-affected ions, particularly Na+, Cl−, and NH4+-N, suggested that there were similar pollution sources and transportation pathways of both inorganic and organic pollutants in the region. The combination of DOM fluorescence properties and inorganic ions could provide an important reference for the pollution source characterization and river basin management.
https://ift.tt/2qPo9g0
Virtual Dental Patient: How Long Until It’s Here?
Abstract
Purpose of Review
Recent developments in digital technology to be generated by superimposing different 3D imaging datasets. The aim of this literature review was to provide an update on the current status of knowledge, to report on the progress in virtual patient science, and to identify further research needed to facilitate the translation to clinical practice.
Recent Findings
Case reports were identified describing different dental patient simulation techniques. Publications focused mainly on methodological feasibility of combining skeletal, facial, and dental imaging to produce virtual simulations. Clinical randomized controlled trials were scarce.
Summary
Superimposition of 3D medical data files is a feasible technique to create a virtual patient under static conditions. 3D image fusion is of interest and importance in all fields of dental medicine including diagnostics, treatment, science, and education. Future research should focus on simplifying the technology, to enable virtual patient simulation to be generated in a single-step approach.
https://ift.tt/2K6I3fu
Vitamin Status and Mineralized Tissue Development
Abstract
Purpose of Review
The physiological control of mineralized tissue development is mediated by two processes: mineralization, such as bone formation due to osteoblast activity, and mineralized tissue destruction by osteoclast bone resorption. In this system, nutritional status, including vitamin intake, influences each regulatory processes, although definite responding mechanisms in target cells vary according to each compound.
Recent Findings
In contrast with water-soluble vitamins that constant supply is required, fat-soluble vitamins such as vitamin D and K are stored in the liver and fat tissue for long time. They are metabolized into congeneric compounds with various activities to participate in the local mineralization process in the body.
Summary
During physiological or non-physiological mineralization, the local actions of vitamin D and K are regulated by nutrient factor derived from dietary supply, and influenced by systemic calcium metabolism and homeostasis.
https://ift.tt/2F6Ye8N
A Leptolyngbya -based microbial consortium for agro-industrial wastewaters treatment and biodiesel production
Abstract
A mixed cyanobacterial-mixotrophic algal population, dominated by the filamentous cyanobacterium Leptolyngbya sp. and the microalga Ochromonas (which contributed to the total photosynthetic population with rates of less than 5%), was studied under non-aseptic conditions for its efficiency to remove organic and inorganic compounds from different types of wastes/wastewaters while simultaneously producing lipids. Second cheese whey, poplar sawdust, and grass hydrolysates were used in lab-scale experiments, in photobioreactors that operated under aerobic conditions with different initial nutrient (C, N and P) concentrations. Nutrient removal rates, biomass productivity, and the maximum oil production rates were determined. The highest lipid production was achieved using the biologically treated dairy effluent (up to 14.8% oil in dry biomass corresponding to 124 mg L−1) which also led to high nutrient removal rates (up to 94%). Lipids synthesized by the microbial consortium contained high percentages of saturated and mono-unsaturated fatty acids (up to 75% in total lipids) for all the substrates tested, which implies that the produced biomass may be harnessed as a source of biodiesel.
https://ift.tt/2qRpTFD
Editorial Board
Source:Biosensors and Bioelectronics, Volume 111
https://ift.tt/2F6HTB3
Retraction notice to An imprinted Ag@CdS core shell nanoparticle based optical-electrochemical dual probe for trace level recognition of ferritin Biosensors and Bioelectronics Volume 63, 15 January 2015, Pages 301-310
Source:Biosensors and Bioelectronics, Volume 111
Author(s): Santanu Patra, Ekta Roy, Rashmi Madhuri, Prashant K. Sharma
https://ift.tt/2K0ZTQV
Facile one-pot synthesis of visible light-responsive BiPO4/nitrogen doped graphene hydrogel for fabricating label-free photoelectrochemical tetracycline aptasensor
Source:Biosensors and Bioelectronics, Volume 111
Author(s): Lan Ge, Henan Li, Xiaojiao Du, Mingyue Zhu, Wei Chen, Tingyan Shi, Nan Hao, Qian Liu, Kun Wang
It is fundamental to develop highly efficient visible light-responsive photoelectrochemical (PEC) performance material for fabricating PEC biosensor. Herein, BiPO4/three-dimensional nitrogen doped graphene hydrogel (3DNGH) nanocomposites were prepared for the first time via a facile one-pot hydrothermal route. In this nanoarchitecture, the BiPO4 nanorods were anchored onto the porous structure of 3DNGH. Compared with pristine BiPO4, the absorption of BiPO4/3DNGH has been extend to visible-light region, and the energy band gap of BiPO4/3DNGH was calculated to be 2.10 eV, which was greatly narrower than that of pristine BiPO4 with a band gap of 3.85 eV. Under visible light irradiation, the photocurrent signal of the as-prepared BiPO4/3DNGH was 847.2-fold, 4.1-fold and 2.3-fold enhanced comparing to pristine BiPO4, BiPO4 functionalized reduced graphene oxide and BiPO4/nitrogen doped graphene. The enhancement of such photocurrent signal was attributed to the introduction of 3DNGH, which was capable to improve the charge transfer rate and also the efficiency of visible-light utilization of BiPO4. Based on the excellent PEC properties of BiPO4/3DNGH, a label-free PEC aptasensor for selectivity and sensitivity detection of tetracycline (Tc) was successfully established by using Tc aptamer as a biorecognition element. Under optimized conditions, the proposed PEC aptasensor exhibited a wide linear in the range from 0.1 nmol L−1 to 1 μmol L−1 as well as a low detection limit of 0.033 nmol L−1 (S/N = 3). The prepared BiPO4/3DNGH nanocomposites would serve as a promising visible light-responsive photoactive material for fabrication of PEC biosensors with high performance.
https://ift.tt/2JdJdo8
Electrochemical biointerfaces based on carbon nanotubes-mesoporous silica hybrid material: Bioelectrocatalysis of hemoglobin and biosensing applications
Source:Biosensors and Bioelectronics, Volume 111
Author(s): Marcos Eguílaz, Reynaldo Villalonga, Gustavo Rivas
We are reporting a novel biosensing platform based on a hybrid nanomaterial that combines the advantages of Nafion-coated multiwalled carbon nanotubes (MWCNTs) and mesoporous silica MCM41 nanoparticles functionalized with hemoglobin (Hb). MWCNTs-MCM41-Hb hybrid bioconjugate was characterized by scanning electron microscopy (SEM), UV–vis spectroscopy and electrochemical techniques after deposition at glassy carbon electrodes (GCE). The combination of the high surface area, biocompatibility and protein loading capacity of MCM41 nanoparticles and the high surface area and catalytic properties of MWCNTs allowed the direct electron transfer (DET) between Hb and the electrode surface. The electron transfer rate constant (k) and the surface coverage of electroactive Hb (ΓHb) were 5.2 s−1 and 4.7 × 10−10 mol cm−2, respectively. The GCE modified with the nanostructured architecture (GCE/MWCNTs-MCM41-Hb) was successfully used as a third-generation biosensor for the highly sensitive and selective quantification of nitrite (NO2-) and trichloroacetic acid (TCA) by taking advantage of the excellent biocatalytic activity of Hb and the efficient direct charge transfer of the heme group.
https://ift.tt/2K0ZSfP
AuNP-RF sensor: An innovative application of RF technology for sensing pathogens electrically in liquids (SPEL) within the food supply chain
Publication date: 15 July 2018
Source:Biosensors and Bioelectronics, Volume 111
Author(s): Leann Lerie Matta, Saranraj Karuppuswami, Premjeet Chahal, Evangelyn C. Alocilja
Rapid detection techniques of pathogenic bacteria in the liquid food supply chain are of significant research interest due to their pivotal role in preventing foodborne outbreaks, and in maintaining high standards of public health and safety. Milk and dairy products are of particular interest due to their widespread consumption across the globe. In this paper, a biosensor for detecting pathogenic bacteria in milk using dextrin-capped gold nanoparticles (d-AuNP) as labels decoded at microwave frequencies is presented. The SPEL (sensing pathogens electrically in liquids) biosensor consists of a 3D printed vial and uses an RF reader and an RFID (radio-frequency identification) compatible Split Ring Resonator (SRR) based tag. The SPEL biosensor is capable of detecting bacteria at 5 log CFU/mL within 75 min, with the possibility of testing multiple concurrent samples. Detection is based on impedance loading of SRR by d-AuNP bound to pathogenic bacteria. Spectrophotometry, along with carbohydrate-functionalized magnetic nanoparticle (MNP) cell capture, is used to verify the sensitivity of the SPEL biosensor with respect to d-AuNP presence. The proof-of-concept device, along with challenges and opportunities for commercialization, are also outlined.
Graphical abstract
https://ift.tt/2F6UhAZ
Electric-field driven assembly of live bacterial cell microarrays for rapid phenotypic assessment and cell viability testing
Publication date: 15 July 2018
Source:Biosensors and Bioelectronics, Volume 111
Author(s): Meenal Goel, Abhishek Verma, Shalini Gupta
Microarray technology to isolate living cells using external fields is a facile way to do phenotypic analysis at the cellular level. We have used alternating current dielectrophoresis (AC-DEP) to drive the assembly of live pathogenic Salmonella typhi (S.typhi) and Escherichia coli (E.coli) bacteria into miniaturized single cell microarrays. The effects of voltage and frequency were optimized to identify the conditions for maximum cell capture which gave an entrapment efficiency of 90% in 60 min. The chip was used for calibration-free estimation of cellular loads in binary mixtures and further applied for rapid and enhanced testing of cell viability in the presence of drug via impedance spectroscopy. Our results using a model antimicrobial sushi peptide showed that the cell viability could be tested down to 5 μg/mL drug concentration under an hour, thus establishing the utility of our system for ultrafast and sensitive detection.
Graphical abstract
https://ift.tt/2K53ayB
Non-enzymatic sensing of glucose using screen-printed electrode modified with novel synthesized CeO2@CuO core shell nanostructure
Source:Biosensors and Bioelectronics, Volume 111
Author(s): Dayakar T., K. Venkateswara Rao, K. Bikshalu, V. Malapati, Kishor Kumar Sadasivuni
We fabricated a fourth generation glucose biosensor using CeO2@CuO core shell nano structure (CeCCS NSs). A simple leave extract of Ocimum tenuiflorum was used to prepare different wt% of 0.2, 04, 0.6, and 0.8 CuO (shell), above 1 wt% of CeO2 (core). The successful formation was confirmed by various characterization techniques like XRD, Uv–Vis, FTIR, SEM and HR-TEM. In the biosensor, 0.4 wt% of CeCCS NSs has shown efficient properties due to its high surface area. The good conductivity and high catalytic activity towards glucose sensing properties were estimated by screen-printed electrode (SPE). The ampherometric studies of CeCCS/SPE modified electrode have been optimized at potential + 0.4 V, showed a sensitivity of 3319.83 μAm M−1 cm−2 within detection limit of 0.019 μM. More significantly, modified electrodes performed excellently against anti-interference and anti-poisoned activity in glucose sample and exhibited promising results for the sustainable improvement for non-enzymatic sensing applications.
https://ift.tt/2F7szUO
An interdigitated electrode biosensor platform for rapid HLA-B*15:02 genotyping for prevention of drug hypersensitivity
Source:Biosensors and Bioelectronics, Volume 111
Author(s): Gita V. Soraya, Jianxiong Chan, Thanh C. Nguyen, Duc H. Huynh, Chathurika D. Abeyrathne, Gursharan Chana, Marian Todaro, Efstratios Skafidas, Patrick Kwan
Prevention of life threatening hypersensitivity reactions to carbamazepine is possible through pre-treatment screening of the associated HLA-B*15:02 risk allele. However, clinical implementation of screening is hindered by the high cost and slow turnaround of conventional HLA typing methods. We have developed an interdigitated electrode (IDE) biosensor platform utilizing loop mediated isothermal amplification (LAMP) that can rapidly detect the HLA-B*15:02 allele. DNA amplification is followed by solid-phase hybridization of LAMP amplicons to a DNA probe immobilized on the IDE sensor surface, resulting in a change in sensor impedance. The testing platform does not require DNA extraction or post-amplification staining, achieving sample-to-answer in 1 h and 20 min. The platform was tested on 27 whole blood samples (14 HLA-B*15:02 positive and 13 negative) with sensitivity of 92.9% and specificity of 84.6% when applying a cutoff of impedance change. Based on these characters the LAMP-IDE platform has potential to be further developed into point-of-care use to help overcome barriers in HLA-B*15:02 screening.
https://ift.tt/2K3M4RW
The relationship between diurnal temperature range and COPD hospital admissions in Changchun, China
Abstract
Diurnal temperature range (DTR) has been suggested to be an adverse health factor especially related to respiratory and cardiovascular diseases. In the current study, we investigated the association between DTR and chronic obstructive pulmonary disease (COPD) hospital admissions during 2009 to 2012 in northeast city of Changchun, China. Based on generalized additive model (GAM), the effects were expressed as relative risk (RR) values of COPD with 95% confidence intervals (CIs) with each 1 °C increase in DTR. And they were significantly increased with an increment of 1 °C in DTR, modified by season, age, and sex. The elderly were more vulnerable, with relative risk values of 1.048 (1.029, 1.066) in cold season and 1.037 (1.021, 1.053) in warm season. Regarding the gender, the DTR effect on females was greater during cold season and the RR value was 1.051 (1.033, 1.069) on the current day (lag 0). The greater estimates for males appeared at lag 7 days, with RR of 1.019 (0.998, 1.040). A season-specific effect was detected that the relative risk values with per 1 °C increase in DTR were greater in cold season than in warm season. These findings support the hypothesis of significant relationship between DTR and COPD in Changchun, one northeast city of China.
https://ift.tt/2HiWHCD
A comparison of blood metal levels in autism spectrum disorder and unaffected children in Shenzhen of China and factors involved in bioaccumulation of metals
Abstract
The present study compared blood plasma metals in children with autism spectrum disorder (ASD) with those in unaffected children in Shenzhen (China). Factors associated with the metal bioaccumulation were further investigated. Thirty-four blood samples of children with ASD were collected in a local hospital (Shenzhen Children's Hospital), while those of 38 unaffected children were from a local large public kindergarten, during March to April in 2016. Metal analysis was carried out by inductively coupled plasma-optical emission spectrometry. The results showed that children with ASD had higher (P < 0.01, 0.05) Pb (ASD 31.9 μg/L, unaffected children 18.6 μg/L), Hg (3.83, and 1.09 μg/L), and Cd (0.70 and 0.26 μg/L) than unaffected children, while essential elements Zn (ASD 4552.0 μg/L, unaffected children 5118.6 μg/L), Se (61.7 and 90.6 μg/L), and Mn (13.5 and 21.4 μg/L) showed an opposite pattern. Moreover, the children exposed to passive smoking had higher (P < 0.05) Cd (passive smoking 1.08 μg/L; non-passive smoking 0.22 μg/L) than those without the exposure. Positive associations were found between levels of Hg or Pb and seafood consumption as well as body mass index (BMI). More future work is needed in order to clarify the association between metal exposure and ASD occurrence in China.
https://ift.tt/2qRlEdb
Efficiency in the European agricultural sector: environment and resources
Abstract
This article intends to compute agriculture technical efficiency scores of 27 European countries during the period 2005–2012, using both data envelopment analysis (DEA) and stochastic frontier analysis (SFA) with a generalized cross-entropy (GCE) approach, for comparison purposes. Afterwards, by using the scores as dependent variable, we apply quantile regressions using a set of possible influencing variables within the agricultural sector able to explain technical efficiency scores. Results allow us to conclude that although DEA and SFA are quite distinguishable methodologies, and despite attained results are different in terms of technical efficiency scores, both are able to identify analogously the worst and better countries. They also suggest that it is important to include resources productivity and subsidies in determining technical efficiency due to its positive and significant exerted influence.
https://ift.tt/2vBBHS8
Role of noninvasive imaging of cerebral arterial system in ischemic stroke: Comparison of transcranial color-coded doppler sonography with magnetic resonance angiography
Betty Simon, Sunithi Elizabeth Mani, Shyamkumar Nidugala Keshava, Mathew Alexander, Sanjith Aaron
Journal of Clinical Imaging Science 2018 8(1):19-19
Aim: To determine the accuracy of transcranial color-coded Doppler sonography (TCCS) in the evaluation of cerebral arterial system in patients with ischemic stroke attending a tertiary care hospital in South India. Objectives: (1) To describe the topographical distribution of atherosclerotic lesions in the cerebral circulation in patients presenting with ischemic stroke from the Indian subcontinent and (2) to determine the accuracy of TCCS for detection and quantification of intracranial stenoses in various segments of the intracerebral arterial system in comparison with magnetic resonance angiography (MRA). Materials and Methods: The demographic profile and risk factors of consecutive patients who presented to neurology outpatient department with cerebral ischemia and scheduled for MRA were determined. These patients had undergone neck Doppler, TCCS, and MRA. The agreement between the MRA and TCCS was assessed using kappa statistics. The sensitivity, specificity, and positive and negative predictive values of TCCS as compared to MRA were calculated. Results: Ninety patients were included in the final analysis. Intracranial atherosclerosis was found in 35.6% of cases. The agreement between TCCS and MRA in detecting lesions for the different arterial segments in the intracranial circulation was 0.83 for anterior cerebral artery (ACA), 0.66 for M1 segment of middle cerebral artery (MCA), 0.45 for M2 segment of MCA, 0.86 for terminal internal carotid artery (TICA), 0.46 for posterior cerebral artery (PCA), and 0.81 for vertebral artery (VA). The sensitivity for the detection of hemodynamically significant arterial lesions in different vascular segments was 100%, 70%, 33.3%, 90.9%, 33.3%, and 72.7% for ACA, M1, M2, TICA, PCA, and VA, respectively. Conclusion: Intracranial atherosclerosis was found to be the predominant distribution of cerebral atherosclerosis. TCCS is a safe method for evaluation of proximal basal cerebral arteries in the intracranial circulation with relatively better sensitivity in the anterior circulation.
https://ift.tt/2JfHzCx
Journal of Clinical Imaging Science 2018 8(1):19-19
Aim: To determine the accuracy of transcranial color-coded Doppler sonography (TCCS) in the evaluation of cerebral arterial system in patients with ischemic stroke attending a tertiary care hospital in South India. Objectives: (1) To describe the topographical distribution of atherosclerotic lesions in the cerebral circulation in patients presenting with ischemic stroke from the Indian subcontinent and (2) to determine the accuracy of TCCS for detection and quantification of intracranial stenoses in various segments of the intracerebral arterial system in comparison with magnetic resonance angiography (MRA). Materials and Methods: The demographic profile and risk factors of consecutive patients who presented to neurology outpatient department with cerebral ischemia and scheduled for MRA were determined. These patients had undergone neck Doppler, TCCS, and MRA. The agreement between the MRA and TCCS was assessed using kappa statistics. The sensitivity, specificity, and positive and negative predictive values of TCCS as compared to MRA were calculated. Results: Ninety patients were included in the final analysis. Intracranial atherosclerosis was found in 35.6% of cases. The agreement between TCCS and MRA in detecting lesions for the different arterial segments in the intracranial circulation was 0.83 for anterior cerebral artery (ACA), 0.66 for M1 segment of middle cerebral artery (MCA), 0.45 for M2 segment of MCA, 0.86 for terminal internal carotid artery (TICA), 0.46 for posterior cerebral artery (PCA), and 0.81 for vertebral artery (VA). The sensitivity for the detection of hemodynamically significant arterial lesions in different vascular segments was 100%, 70%, 33.3%, 90.9%, 33.3%, and 72.7% for ACA, M1, M2, TICA, PCA, and VA, respectively. Conclusion: Intracranial atherosclerosis was found to be the predominant distribution of cerebral atherosclerosis. TCCS is a safe method for evaluation of proximal basal cerebral arteries in the intracranial circulation with relatively better sensitivity in the anterior circulation.
https://ift.tt/2JfHzCx
Presynaptic dopaminergic neuroimaging in REM sleep behavior disorder: a systematic review and meta-analysis
The presence of polysomnography-confirmed REM sleep behavior disorder (RBD) is the stronger risk factor for having prodromal Parkinson disease (PD), followed by abnormal presynaptic dopaminergic radionuclide neuroimaging. Aim of the review is to conduct a meta-analysis of literature data regarding presynaptic dopaminergic neuroimaging in RBD.A literature search was conducted, resulting in 16 papers that met the inclusion criteria. Clinical and neuroimaging data were extracted. The studies are heterogeneous, especially for neuroimaging methodology.
https://ift.tt/2HjiIkQ
Εγγραφή σε:
Αναρτήσεις (Atom)
-
Summary Insulinomas are rare neuroendocrine tumours that classically present with fasting hypoglycaemia. This case report discusses an un...
-
The online platform for Taylor & Francis Online content New for Canadian Journal of Remote Sen...
