Source:Journal of the Academy of Nutrition and Dietetics
Author(s): Christina Rollins, Stephanie Dobak
http://ift.tt/2oLuYjX
Medicine by Alexandros G. Sfakianakis,Anapafseos 5 Agios Nikolaos 72100 Crete Greece,00302841026182,00306932607174,alsfakia@gmail.com,
Increased atmospheric nitrogen (N) deposition is known to alter ecosystem carbon source-sink dynamics through changes in soil CO2 fluxes. However, a limited number of experiments have been conducted to assess the effects of realistic N deposition in the Mediterranean Basin, and none of them have explored the effects of N addition on soil respiration (R s ). To fill this gap, we assessed the effects of N supply on R s dynamics in the following two Mediterranean sites: Capo Caccia (Italy), where 30 kg ha−1 year−1 was supplied for 3 years, and El Regajal (Spain), where plots were treated with 10, 20, or 50 kg N ha−1 year−1 for 8 years. Results show a complex, non-linear response of soil respiration (R s ) to N additions with R s overall increasing at Capo Caccia and decreasing at El Regajal. This suggests that the response of R s to N addition depends on dose and duration of N supply, and the existence of a threshold above which the N introduced in the ecosystem can affect the ecosystem's functioning. Soil cover and seasonality of precipitations also play a key role in determining the effects of N on R s as shown by the different responses observed across seasons and in bare soil vs. the soil under canopy of the dominant species. These results show how increasing rates of N addition may influence soil C dynamics in semiarid ecosystems in the Mediterranean Basin and represent a valuable contribution for the understanding and the protection of Mediterranean ecosystems.
Perfluorooctane sulfonate (PFOS), an artificial fluorosurfactant and global contaminant, is used widely in various consumer products. In this study, we investigated the function of estrogen receptor β (ERβ) in PFOS-induced bile acid and cholesterol metabolism disorders and gut microbiome using ERβ knockout mice that were exposed to PFOS by gavage. Our results showed that a daily dose of 5 mg PFOS/kg significantly induced hydropic degeneration and vacuolation in hepatic cells, reduced bile acid, and cholesterol levels in liver tissue, and influenced the abundance and composition of gut microbiota. Notably, ERβ deficiency not only ameliorated morphological alterations of hepatocytes but also relieved disorders in bile acids and cholesterol metabolism caused by PFOS. Furthermore, the changes in the gut microbiome by PFOS were also modulated. The relative transcript abundance of key genes involved in bile acid and cholesterol metabolism exhibited similar changes. In HepG2 cells, PFOS increased ERβ expression, which could be blocked by adding PHTPP (a selective antagonist of ERβ). Our study thus provides new evidence that ERβ mediates PFOS-induced hepatotoxicity.
Nitrogen (N) deposition due to anthropogenic pollution is a major driver of the global biodiversity loss. We studied the effect of experimental N and phosphorus (P) fertilization (0, 10, 20, and 50 kg N ha−1 year−1 and 14 kg P ha−1 year−1 over the background deposition levels) on plant cover dynamics of a rosemary (Rosmarinus officinalis L.) shrubland after 8 years of nutrient addition in a semiarid Mediterranean ecosystem from Central Spain. We specifically aimed at testing whether N deposition has the potential to influence the observed expanding trend of woody vegetation into areas dominated by grassland, biological soil crusts, and bare soil. Our results show that N addition loads above 10 kg N ha−1 year−1 reverted the cover dynamics of shrubs. Under N addition conditions, N was no longer a limiting nutrient and other elements, especially P and calcium, determined the seasonal growth of young twigs. Interestingly, N fertilization did not inhibit the growth of young shoots; our estimates point to a reduced rosemary leaf lifespan that is driving individuals to death. This may be triggered by long-term accumulation of N compounds in leaves, suggesting the need to consider the old organs and tissues in long-lived perennial plants, where N toxicity effects could be more mediated by accumulation processes. Shrublands are a widely distributed ecosystem type in biodiverse Mediterranean landscapes, where shrubs play a key role as nurse plants. Therefore, the disappearance of shrublands may accelerate the biodiversity loss associated with other global change drivers, hamper the recruitment of seedlings of woody species, and, as a consequence, accelerate desertification.
Monensin is a common antiparasitic drug given to poultry that contaminates poultry manure and bedding material (broiler litter). As broiler litter is commonly applied to agricultural fields as fertilizer, monensin could be released beyond the farm if it is not retained or degraded in the soil. This study aimed to assess the impact of long-term surface application of broiler litter (i.e., 17 years) on the capacity of pasture soil to sorb monensin. The soils were exposed to a range of monensin concentrations (0.18 to 1.81 μmol L−1), solution pH (pH 4–9), and temperatures (15, 25, and 35 °C) and monensin was measured as loss from solution (i.e., sorption). Soils receiving long-term litter applications were hypothesized to retain more monensin than unamended soils because they have higher organic matter concentrations. However, soils from broiler litter-amended fields sorbed 46% less monensin than soils from unamended fields, likely because broiler litter also increased soil pH. The sorption of monensin to soil was strongly influenced by pH, with an order of magnitude greater sorption at pH 4 than at pH 9. Both soils had similar capacity to sorb monensin under similar solution pH, despite differences in organic carbon content (with the broiler litter-amended having 25% greater relative to the unamended soil). Temperature did not significantly impact monensin sorption for either soil. Our findings suggest increasing soil pH, for instance through liming, could enhance mobility of monensin.
Among the solutions for the achievement of environmental sustainability in the energy sector, district heating (DH) with combined heat and power (CHP) systems is increasingly being used. The Italian city of Turin is in a leading position in this field, having one of the largest DH networks in Europe. The aim of this work is the analysis of a further development of the network, addressed to reduce the presence of pollutants in a city that has long been subject to high concentration levels. The environmental compatibility of this intervention, especially in terms of nitrogen oxides (NOx) and particulate matter (PM) emissions, is evaluated. The pollutants dispersion is estimated using the CALPUFF model. The forecasting scenario is created firstly by simulating the energy production of the main generation plants in response to the estimated heat demand, and secondly by investigating the amount and the dispersion of pollutants removed due to the elimination of the centralized residential heaters. The results show a future reduction in ground level average NOx concentration ranging between 0.2 and 4 μg/m3. The concentration of PM remains almost unchanged. Measures are then taken to lower the uncertainty in the simulation scenarios. This study provides important information on the effects of a change of the energy configuration on air quality in an urban area. The proposed methodological approach is comprehensive and repeatable.
The present study has been carried out to examine the role of earthworms in phytoremediation of Cd and its effect on growth, pigment content, expression of genes coding key enzymes of pigments, photosynthetic efficiency and osmoprotectants in Brassica juncea L. plants grown under cadmium (Cd) metal stress. The effect of different Cd concentrations (0.50, 0.75, 1.0, 1.25 mM) was studied in 30 and 60-day-old plants grown in soils containing earthworms. It was observed that earthworm inoculation showed stimulatory effect on phytoremediation capacity and Cd uptake has increased by 49% (in 30-day-old plants) and 35% (in 60-day-old plants) in shoots and 13.3% (in 30-day-old plants) and 10% (in 60-day-old plants) in roots in 30 and 60-day-old plants in Cd (1.25 mM) treatments. Plant growth parameters such as root and shoot length, relative water content and tolerance index were found to increase in the presence of earthworms. Recovery in photosynthetic pigments (chlorophyll and carotenoid) and gas exchange parameters, i.e. net photosynthetic rate (P n ), stomatal conductance (G s ), intercellular CO2 concentration (C i ) and transpiration rate (E t ), was observed after earthworm's supplementation. Modulation in expression of key enzymes for pigment synthesis, i.e. chlorophyllase, phytoene synthase, chalcone synthase and phenylalanine ammonia lyase, was also observed. The results of our study revealed that earthworms help to mitigate the toxic effects produced by Cd on plant growth and photosynthetic efficiency along with enhanced phytoremediation capacity when co-inoculated with Cd in soil.
Abandoned tailing dumps (ATDs) offer an opportunity to identify the main physicochemical filters that determine colonization of vegetation in solid mine wastes. The current study determined the soil physicochemical factors that explain the compositional variation of pioneer vegetal species on ATDs from surrounding areas in semiarid Mediterranean-climate type ecosystems of north-central Chile (Coquimbo Region). Geobotanical surveys—including physicochemical parameters of substrates (0–20 cm depth), plant richness, and coverage of plant species—were performed on 73 ATDs and surrounding areas. A total of 112 plant species were identified from which endemic/native species (67%) were more abundant than exotic species (33%) on ATDs. The distribution of sampling sites and plant species in canonical correspondence analysis (CCA) ordination diagrams indicated a gradual and progressive variation in species composition and abundance from surrounding areas to ATDs because of variations in total Cu concentration (1.3%) and the percentage of soil particles <2 μm (1.8%). According to the CCA, there were 10 plant species with greater abundance on sites with high total Cu concentrations and fine-textured substrates, which could be useful for developing plant-based stabilization programs of ATDs in semiarid Mediterranean-climate type ecosystems of north-central Chile.
Two microalgae strains including Chlorella vulgaris and Acutodesmus obliquus were grown on BG11 medium with salinity stress ranging from 0.06 to 0.4 M NaCl. Highest lipid content in C. vulgaris and A. obliquus was 49 and 43% in BG11 amended with 0.4 M NaCl. The microalgal strains C. vulgaris and A. obliquus grow better at 0.06 M NaCl concentration than control condition. At 0.06 M NaCl, improved dry biomass content in C. vulgaris and A. obliquus was 0.92 and 0.68 gL−1, respectively. Stress biomarkers like reactive oxygen species, antioxidant enzyme catalase, and ascorbate peroxidase were also lowest at 0.06 M NaCl concentration revealing that both the microalgal strains are well acclimatized at 0.06 M NaCl concentration. The fatty acid composition of the investigated microalgal strains was also improved by increased NaCl concentration. At 0.4 M NaCl, palmitic acid (37%), oleic acid (15.5%), and linoleic acid (20%) were the dominant fatty acids in C. vulgaris while palmitic acid (54%) and stearic acid (26.6%) were major fatty acids found in A. obliquus. Fatty acid profiling of C. vulgaris and A. obliquus significantly varied with salinity concentration. Therefore, the study showed that salt stress is an effective stress that could increase not only the lipid content but also improved the fatty acid composition which could make C. vulgaris and A. obliquus potential strains for biodiesel production.
To better understand the mechanisms of TiO2 nanoparticle (NP) uptake and toxicity in aquatic organisms, we investigated the interaction of NPs with the proteins found in gill mucus from blue mussels. Mucus is secreted by many aquatic organisms and is often their first line of defense against pathogens, xenobiotics, and other sources of environmental stress. Here, five TiO2 NPs and one SiO2 NP were incubated with gill mucus and run out on a one-dimensional polyacrylamide gel for a comparative qualitative analysis of the free proteins in the mucosal solution and the proteins bound to NPs. We then used nanoscale liquid chromatography coupled with tandem mass spectrometry to identify proteins of interest. Our data demonstrated dissimilar protein profiles between the crude mucosal solution and proteins adsorbed on NPs. In particular, extrapallial protein (EP), one of the most abundant mucus proteins, was absent from the adsorbed proteins. After thermal denaturation experiments, this absence was attributed to the EP content in aromatic amino acids that prevents protein unfolding and thus adsorption on the NP. Moreover, although the majority of the protein corona was qualitatively similar across the NPs tested here (SiO2 and TiO2), a few proteins in the corona showed a specific recruitment pattern according to the NP oxide (TiO2 vs SiO2) or crystal structure (anatase TiO2 vs rutile TiO2). Therefore, protein adsorption may vary with the type of NP.
Graphical abstract
The aim of this study was to investigate ameliorative effect of selenium (Se) on lead (Pb)-induced inflammatory damage in chicken testes. One hundred eighty 7-day-old male chickens were randomly assigned into the control group, the Se group, the Pb group, and the Pb/Se group. Lead acetate was added in drinking water (350 mg/L Pb). Sodium selenite was added in the standard commercial diet (1 mg/kg Se). On the 30th, 60th, and 90th days of the experiment, 15 chickens of each group were euthanized. Inductively coupled plasma mass spectrometry, hematoxylin and eosin staining, real-time quantitative PCR, and Western blot were used. The results indicated that excess Pb increased nitric oxide content; inducible nitric oxide synthase (iNOS) activity; nuclear factor-kappa B (NF-κB), tumor necrosis factor-α, cyclooxygenase-2, prostaglandin E synthases, and iNOS mRNA levels in a time-dependent manner; NF-κB, iNOS, heat shock protein (HSP) 60, HSP70, and HSP90 protein levels; and Pb concentration. Excess Pb decreased Se concentration and induced histological changes. Se-alleviated Pb caused all of the above changes. Se improved Pb-caused inflammatory damage by decreasing the expression of inflammatory factors and heat shock proteins in the chicken testes. Our results provided theoretical basis of an alleviative effect of Se on Pb-induced bird testis damage.
The study was conducted to evaluate metabolic answer of Lepidium sativum L. on Hg, compost, and citric acid during assisted phytoextraction. The chlorophyll a and b contents, total carotenoids, and activity of peroxidase were determined in plants exposed to Hg and soil amendments. Hg accumulation in plant shoots was also investigated. The pot experiments were provided in soil artificially contaminated by Hg and/or supplemented with compost and citric acid. Hg concentration in plant shoots and soil substrates was determined by cold vapor atomic absorption spectroscopy (CV-AAS) method after acid mineralization. The plant photosynthetic pigments and peroxidase activity were measured by standard spectrophotometric methods. The study shows that L. sativum L. accumulated Hg in its aerial tissues. An increase in Hg accumulation was noticed when soil was supplemented with compost and citric acid. Increasing Hg concentration in plant shoots was correlated with enhanced activation of peroxidase activity and changes in total carotenoid concentration. Combined use of compost and citric acid also decreased the chlorophyll a and b contents in plant leaves. Presented study reveals that L. sativum L. is capable of tolerating Hg and its use during phytoextraction assisted by combined use of compost and citric acid lead to decreasing soil contamination by Hg.
Four aqueous extracts of different plant organs are the following: Artemisia herba-alba, Opuntia ficus-indica, Camellia sinensis and Phlomis crinita were evaluated against two bacterial strains: Porphyromonas gingivalis and Prevotella intermedia, which are implicated in periodontal diseases. By using a disc method, these plant extracts demonstrated powerful bacterial activity against these Gram-negative strains. The minimum inhibitory concentration values of the four plant extracts varied between 0.03 and 590.82 mg/ml for the microbes. Another assay using commercial antibiotics and antibacterials as positive controls was also conducted. Values obtained after statistical analysis of inhibition diameters of all plant extracts demonstrated that for P. gingivalis, the aqueous extracts of A. herba-alba and O. ficus-indica were most effective, followed by those of C. sinensis and P. crinita. For P. intermedia, aqueous extracts of O. ficus-indica and C. sinensis appeared to be more efficient with significantly different (P > 0.05) inhibition diameters, followed by those of O. ficus-indica and P. crinita. In summary, the statistical results reveal that these plant extracts exert stronger antibacterial activity on P. intermedia germ as compared to P. gingivalis.
Glass surface cleaning is the very first step in advanced coating deposition and it also finds use in conserving museum objects. However, most of the wet chemical methods of glass cleaning use toxic and corrosive chemicals like concentrated sulfuric acid (H2SO4), piranha (a mixture of concentrated sulfuric acid and 30% hydrogen peroxide), and hydrogen fluoride (HF). On the other hand, most of the dry cleaning techniques like UV-ozone, plasma, and laser treatment require costly instruments. In this report, five eco-friendly wet chemical methods of glass cleaning were evaluated in terms of contact angle (measured by optical tensiometer), nano-scale surface roughness (measured by atomic force microscopy or AFM), and elemental composition (measured by energy dispersive x-ray spectroscopy or SEM-EDX). These glass cleaning methods are devoid of harsh chemicals and costly equipment, hence can be applied in situ in close proximity with plantation such as greenhouse or upon subtle objects such as museum artifacts. Out of these five methods, three methods are based on the chemical principle of chelation. It was found that the citric acid cleaning method gave the greatest change in contact angle within the hydrophilic regime (14.25° for new glass) indicating effective cleansing and the least surface roughness (0.178 nm for new glass) indicating no corrosive effect. One of the glass sample showed unique features which were traced backed to the history of the glass usage.
Publication date: Available online 6 April 2017
Source:Hematology/Oncology and Stem Cell Therapy
Author(s): Jose Sandoval-Sus, Eduardo M. Sotomayor, Bijal D. Shah
Mantle cell lymphoma is a clinically heterogeneous disease occurring within a heterogeneous patient population, highlighting a need for personalized therapy to ensure optimal outcomes. It is therefore critical to understand the benefits and risks associated with both intensive and deintensified approaches. In the following review we provide a therapeutic roadmap to strategically guide treatment for newly diagnosed and relapsed/refractory patients highlighting pivotal and recently published results involving known and novel therapies.
http://ift.tt/2o3RuBP
Publication date: Available online 6 April 2017
Source:Hematology/Oncology and Stem Cell Therapy
Author(s): Bushra Salman, Mohammed Al-Zaabi, Mohammed Al-Huneini, David Dennison, Abdulhakeem Al-Rawas, Salam Al-Kindi, Khalil Al-Farsi, Melanie Tauro, Murtadha Al-Khabori
Busulfan (Bu)-based preparative regimens in hematopoietic stem cell transplantation are commonly used. Previous studies have shown that Bu at a fixed dose of 3.2 mg/kg/day (FBD) given intravenously decreases variability in drug pharmacokinetics and this decreases the dependency on therapeutic drug monitoring (TDM) of Bu. We compared the Bu dose given using TDM with the FBD of 3.2 mg/kg/day. Seventy-three patients with acute leukemia, myelodysplasia, chronic myeloid leukemia, thalassemia major, and sickle cell disease were included. The mean age at transplant was 15 years (range 2–55 years) with 57% adults. Indication for transplantation was leukemia/myelodysplastic syndrome in 46% of the patients, while the remaining 54% were transplanted for inherited blood disorders. We found that the median FBD was lower than the median TDM dose by 39 mg/day with a statistically significant difference (p < .001) even after adjusting for the weight (median total FBD of 349 mg, median TDM dose of 494 mg, p < .0001). Age and underlying condition (malignant vs. nonmalignant) were the main factors affecting Bu clearance (p < .001 and p < .07, respectively). TDM remains an important tool for the appropriate dosing of Bu in preparative regimens of hematopoietic stem cell transplantation, especially in populations with genetic admixture.
http://ift.tt/2oL7Hyt
Publication date: Available online 6 April 2017
Source:Hematology/Oncology and Stem Cell Therapy
Author(s): Ali H. Algiraigri, Nicola A.M. Wright, Elizabeth Oddone Paolucci, Aliya Kassam
Nontransfusion-dependent β-thalassemia (NTDβT) syndromes consist of β-thalassemia intermedia and moderate hemoglobin E/β thalassemias. They are characterized by varying degrees of chronic anemia and a wide spectrum of complications due to ineffective erythropoiesis and iron overload from chronic transfusions. Hydroxyurea (HU), an oral chemotherapeutic drug, is anticipated to decrease disease severity. We performed a meta-analysis to evaluate the clinical efficacy and safety of HU in NTDβT patients of any age. MEDLINE, EMBASE, Cochrane databases, and major conference proceedings for studies that assessed HU in NTDβT patients were searched. Qualities of eligible studies were assessed by National Institutes of Health tools. Seventeen studies, collectively involving 709 patients, fulfilled the eligibility criteria. HU was associated with a significant decrease in transfusion need in severe NTDβT with complete and overall (≥ 50%) response rates of 42% and 79%, respectively. For mild NTDβT, HU was effective in raising hemoglobin by 1 g/L in 64% of patients. HU appears to be effective, well tolerated, and associated with mild and transient adverse events. NTDβT patients may benefit from a trial of HU, although large randomized clinical trials assessing its efficacy should be conducted to confirm the findings of this meta-analysis and to assess its long-term toxicity and response sustainability.
http://ift.tt/2o3I894
Physical activity is an effective therapeutic tool for cardiovascular risk prevention. However, exercise aerobic capacity of patients with type 1 diabetes (T1DM) has not been thoroughly investigated. Aim of the present study is to evaluate exercise aerobic capacity in patients with T1DM compared to a normal control population.
This observational study included 17 T1DM patients and 17 matched healthy volunteers. Cardiopulmonary exercise test (CPET) was conducted on an electronically-braked cycle ergometer. Blood samples were collected for evaluation of glycemia and lactate levels.
Mean oxygen uptake at peak exercise (VʹO2,peak) was significantly lower in T1DM subjects (V′O2,peak T1DM 2200 ± 132ml/min vs VʹO2,peak Healthy subjects of 2659 ± 120 ml/min p = 0.035). Cardiovascular response analysis did not show statistically significant differences. Respiratory exchange ratio (RER) was significantly higher in healthy subjects at peak exercise and at the first minute of recovery (p = 0.022, p = 0.024). Peak exercise lactate levels were significantly higher in healthy subjects. There was no statistical correlation between CPET results and diabetes-related parameters.
Patients affected by T1DM have a worse exercise tolerance than normal subjects. The two groups differed by RER which can be greatly influenced by the substrate type utilized to produce energy. Because of the impaired carbohydrate utilization, T1DM subjects may use a larger amount of lipid substrates, such hypothesis could be strengthened by the lower lactate levels found in T1DM group at peak exercise. The lack of correlation between exercise tolerance and disease-related variables suggests that the alterations found could be independent from the glycemic levels.
Publication date: July 2017
Source:Biomaterials, Volume 131
Author(s): Guo-Wu Wang, Hui Yang, Wei-Feng Wu, Ping Zhang, Jin-Ye Wang
Various degradable biomaterials have been used to bridge injured peripheral nerve defect; however, drawbacks such as poor mechanical properties, inappropriate degradation rate, and toxic degradation products continue to limit the application of them in nerve repair. Considering the unique properties of zein, such as its biocompatibility, biodegradability and ease of fabrication, we report the use of zein conduits to repair injured rat sciatic nerves with a 10-mm defect. Three-dimensional zein conduits were designed with/without pores, and with/without microtubes including in the lumen of conduits. Zein conduit with microtubes yielded satisfactory results in sciatic function index (SFI), proximal compound muscle action potentials, density of myelinated nerve fibres and myelin thickness, which were not inferior to autograft but slightly superior to the hollow conduit at the 4th month post-implantation. The conduits degraded almost completely within two months, which was shorter than the suggested period of four months. Thus, the use of a porous conduit with microtubes inside as the guidance may play important roles in successful repair. Notably, the regulatory body will more likely approve designs employing a single component, such as the natural polymer zein.
Publication date: 5 July 2017
Source:Materials & Design, Volume 125
Author(s): Lixi Wang, Xiaojuan Yang, Qitu Zhang, Bo Song, Chingping Wong
La2O2S:Tb3+ phosphors were synthesized by a one-step K2CO3/Na2CO3 flux method and phosphor-embedded polymethylmethacrylate (PMMA) films were fabricated by spin coating. Effects of calcination temperature and flux on the crystal structure, morphology and luminescence performance were evaluated by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, photoluminescence and calculation of CIE color coordinates. In the emission spectra, several emission peaks corresponding to 5D4→7F6, 5D4→7F5, 5D4→7F4, and 5D4→7F3 transitions appeared, with the 5D4→7F3 green emission being the dominant emission. The energy band gap, quantum efficiency, fluorescence decay curves, and thermal stability were also investigated with the aim of exploring the potential applicability of the synthesized phosphors in optical devices.
Publication date: 5 July 2017
Source:Materials & Design, Volume 125
Author(s): Henry Ovri, Erica T. Lilleodden
An elevated temperature nanoindentation based method for characterizing the thermal dependence of plastic instability and assessing the activation energies associated with the phenomenon in Al alloys is presented in this work. The method exploits the nanoscale force–displacement resolution capabilities of the Nanoindenter, precludes the ambiguities inherent in the uniaxial testing based methods and offers increased reliability because of the statistical significance of the data achieved. The activation energies estimated for an Al—Mg and an Al—Li alloy with the proposed method were found to be 0.59±0.07eV and 0.72±0.01eV, respectively, and are consistent with values derived with other methods. The rate controlling mechanisms associated with these activation energies are described in terms of existing models for plastic instability in these alloy systems.
Publication date: 5 July 2017
Source:Materials & Design, Volume 125
Author(s): Ramiz S.M. Samarjy, Alexander F.H. Kaplan
A new variant of additive manufacturing is proposed which involves transferring molten droplets via a laser beam to a substrate. The droplets are generated by laser remote fusion cutting of a supply sheet that could be a waste material, for recycling purposes. The laser-induced ablation pressure at the cutting front continuously drives melt downwards below the supply sheet in the form of a liquid column. Droplets separate from the column and solidify as a track on a substrate below. The droplets, surrounded by vapour, had in this case an average diameter of 500μm and a speed of 2m/s, with deviations up to 50%. Sound clad tracks were generated on steel and aluminium substrates. In the case of a copper substrate discontinuous clad tracks were produced as a result of poor wetting. The droplet jet had a small divergence of about 5°, which is suitable for controlled deposition. The transmitted part of the laser beam interacted with the clad track but did not affect the process result. High speed imaging was found to be a suitable tool for qualitative and quantitative analysis of the technique.
Publication date: 5 July 2017
Source:Materials & Design, Volume 125
Author(s): Weibing Guo, Tianmin Luan, Jingshan He, Jiuchun Yan
Fine-grained aluminum alloys are very heat sensitive and overheating can reduce the strength of the material. Filler metals of Zn-5Al and Zn-5Al-3Cu alloys were used to join fine-grained 7034 aluminum alloy pieces by ultrasonic-assisted soldering at 420°C. We observed excellent dissolution of the filler metal to the base metal. For the Zn-5Al solder, the Al content of the bond layer increased from 25 to 54at.% when the ultrasound time increased from 5 to 60s, resulting in a decrease of the volume fraction of the eutectic phase from 60% to 15%. The maximum tensile strength of the joints reached 208±8MPa and all fractures occurred in the brittle eutectic phase. For the Zn-5Al-3Cu solder, η-Zn and α-Al phases were identified in the bond layer. The maximum tensile strength of the joints was 249±12MPa, which was ~80% of the base metal after the same soldering thermal cycle. In this case, fracture occurred in the η-Zn phase. The higher strength is attributed to the absence of the eutectic phase. When the ultrasonic treatment time was increased to 60s, the volume fraction of α-Al in the bond layer increased to 93%. The strength of the joints decreased as the brittle ZnAl eutectoid phase crystals appeared inside the α-Al phase in the bond layer.
Publication date: 5 July 2017
Source:Materials & Design, Volume 125
Author(s): Yixiang Zhang, Han Ma, Min Yi, Zhigang Shen, Xiaozheng Yu, Xiaojing Zhang
Magnetron-sputtering deposition of coatings onto a flat surface is well established, but coating metal on the curved surface of nanoparticles (NPs) is still challenging. Herein, by using a magnetron sputtering system in which a vibration generator with variable frequency is applied to the sample stage to maintain NPs' dispersity and movability, we successfully deposit noble metal (Au, Ag, Pt) nanodots onto the surface of TiO2 NPs. It is found that the metal nanodots are of a size of 1–6nm and they are firmly bonded to the TiO2 NPs' surface. The photocatalytic activity of Ag/TiO2 is demonstrated to be 2.7 times that of pure TiO2 under simulated sunlight irradiation. This study creates new opportunities for fabricating excellent NP composite catalysts by liquid-free methods.
Publication date: 5 July 2017
Source:Materials & Design, Volume 125
Author(s): P. Asgari, Y. Pourvais, P. Abdollahi, A.R. Moradi, R. Khamedi, A. Darudi
The aim of this paper is to introduce reflective digital holographic microscopy (rDHM) as a new method for quantitative evaluation of corrosion. Despite the commonly-used evaluation methods, rDHM does not require scanning, while it measures the microstructural height profile of the corroded sample surface within a macroscale area. Based on the height profile across the corroded grain boundaries, a quantitative criterion is suggested to distinguish between intergranular and transgranular corrosion. The experimental results show the capability of rDHM to analyse the microstructural corrosion in AISI 304 stainless steel. The presented method can also be applied as a surface characterization method for analysis of a variety of metallurgic effects such as crystal elasticity and crystal orientation.
Publication date: 5 July 2017
Source:Materials & Design, Volume 125
Author(s): Alberto Orozco-Caballero, Marta Álvarez-Leal, David Verdera, Pilar Rey, Oscar A. Ruano, Fernando Carreño
Multi-pass friction stir processing (MP-FSP) can produce extensive bulk nanostructured areas in various metallic materials, such as the Al 7075 alloy (Al-Zn-Mg-Cu), providing fine and highly misoriented grains. This allows obtaining superplastic deformations by the activation of grain boundary sliding (GBS) mechanism at certain strain rate and temperature window, crucial for performing a further superplastic forming (SPF). The superplastic performance of the MP-FSP Al 7075 alloy in two uniaxial testing directions was evaluated and compared to that of a single pass FSP (SP-FSP), reporting a mechanical anisotropy in the MP-FSP attributed to the heterogeneous crystallographic orientation distribution along the transverse testing direction. The operative deformation mechanism was determined by uniaxial tensile test and small punch test (SPT), the former a test with biaxial with radial symmetry. GBS was corroborated as the main operative deformation mechanism in the SP-FSP and MP-FSP, reporting high strain rate superplasticity in the temperature range 350–400°C at 10−2s−1, and maximum elongation values between 290–540% at 400°C depending on the testing direction. The Al 7075 alloy processed by MP-FSP showed a great potential for a further SPF as GBS remains as the global deformation mechanism under biaxial testing conditions.
Publication date: 5 May 2017
Source:Journal of Ethnopharmacology, Volume 203
Author(s): José R. Soberón, Melina A. Sgariglia, Ana C. Pastoriza, Estela M. Soruco, Sebastián N. Jäger, Guillermo R. Labadie, Diego A. Sampietro, Marta A. Vattuone
Ethnopharmacological relevanceAnagallis arvensis L. (Primulaceae) is used in argentinean northwestern traditional medicine to treat fungal infections. We are reporting the isolation and identification of compounds with antifungal activity against human pathogenic yeast Candida albicans, and toxicity evaluation.Aim of the studyto study the antifungal activity of extracts and purified compounds obtained form A. arvensis aerial parts, alone and in combinations with fluconazole (FLU), and to study the toxicity of the active compounds.Materials and methodsDisk diffusion assays were used to perform an activity-guided isolation of antifungal compounds from the aerial parts of A. arvensis. Broth dilution checkerboard and viable cell count assays were employed to determine the effects of samples and combinations of FLU + samples against Candida albicans. The chemical structures of active compounds were elucidated by spectroscopic analysis. Genotoxic and haemolytic effects of the isolated compounds were determined.ResultsFour triterpenoid saponins (1–4) were identified. Anagallisin C (AnC), exerted the highest inhibitory activity among the assayed compounds against C. albicans reference strain (ATCC 10231), with MIC-0 =1µg/mL. The Fractional Inhibitory Concentration Index (FICI=0.129) indicated a synergistic effect between AnC (0.125µg/mL) and FLU (0.031µg/mL) against C. albicans ATCC 10231. AnC inhibited C. albicans 12–99 FLU resistant strain (MIC-0 =1µg/mL), and the FICI=0.188 indicated a synergistic effect between AnC (0.125µg/mL) and fluconazole (16µg/mL). The combination AnC+ FLU exerted fungicidal activity against both C. albicans strains. AnC exerted inhibitory activity against C. albicans ATCC 10231 sessile cells (MIC50=0.5µg/mL and MIC80=1µg/mL) and against C. albicans 12–99 sessile cells (MIC50=0.75µg/mL and MIC80=1.25µg/mL). AnC exerted haemolytic effect against human red blood cells at 15µg/mL and did not exerted genotoxic effect on Bacillus subtilis rec strains.ConclusionsThe antifungal activity and lack of genotoxic effects of AnC give support to the traditional use of A. arvensis as antifungal and makes AnC a compound of interest to expand the available antifungal drugs.
We read with interest the points raised by Piscioli1 and Dunne2 regarding the histological subtyping and risk of metastasis in thin melanomas (tM).
http://ift.tt/2p768HP
Cutaneous squamous cell carcinoma (cSCC) are amongst the most common cancers with metastatic potential. Specific clinical and pathological "high-risk" features are used to determine the risk of loco-regional recurrence1-4. Current national guidelines recommend that patients with "high-risk" disease receive specialist follow-up for 2-3 years1. Whilst guidance on what constitutes "high-risk" disease appears consistent and evidence-based1, guidance on what constitutes "low-risk" disease is comparatively vague (despite good evidence suggesting minimal risk in the absence of "high-risk" factors2), which could result in unnecessary follow-up regimens that are more reflective of local preferences.
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