Real-time Measurement of Stress and Damage Evolution During Initial Lithiation of Crystalline Silicon

Crystalline to amorphous phase transformation during initial lithiation in (100) silicon-wafers is studied in an electrochemical cell with lithium metal as the counter and reference electrode. It is demonstrated that severe stress jumps across the phase boundary lead to fracture and damage, which is an essential consideration in designing silicon based anodes for lithium ion batteries. During initial lithiation, a moving phase boundary advances into the wafer starting from the surface facing the lithium electrode, transforming crystalline silicon into amorphous LixSi. The resulting biaxial compressive stress in the amorphous layer is measured in situ and it was observed to be ca. 0.5 GPa. HRTEM images reveal that the crystalline-amorphous phase boundary is very sharp, with a thickness of ~ 1 nm. Upon delithiation, the stress rapidly reverses, becomes tensile and the amorphous layer begins to deform plastically at around 0.5 GPa. With continued delithiation, the yield stress increases in magnitude, culminating in sudden fracture of the amorphous layer into micro-fragments and the cracks extend into the underlying crystalline silicon.Comment: 12 pages, 5 figure

Study of genetic diversity of wild Caspian trout Salmo trutta caspius in the Sardabrud and Astara Rivers, using D-Loop region sequencing

In this study the genetic diversity of wild Caspian trout (Salmo trutta caspius) in the Sardabroud and Astara Rivers was evaluated using D-Loop region sequencing. For this purpose, 35 specimens of adult Caspian brown trout were collected from these rivers in the Mazandarn and Gilan Provinces in fall and winter 2011. Approximately 3-5 g of soft and fresh fin tissue was isolated and fixed in ethanol 96% and then transferred to the Caspian Sea Ecology Research Center Genetics Laboratory in Sari, Iran. Genomic DNA from the samples was extracted using Ammonium Acetate Method. The quality and quantity of the extracted DNA were assessed by spectrophotometer and agarose gel (1%) electrophoresis. Polymerase Chain Reaction (PCR) was performed on the target DNA using a primers sequence D-Loop region of mtDNA molecule. Then the product was purified and DNA sequencing was carried out using chain termination method. The D-Loop region of Caspian trout contained 654 bp. Data were analyzed using Bio-Edit, DnaSP, Arlequin and Mega software. 20 and 15 haplotypes was observed in Sardabrud and Astara River. The DNA sequence of one of them was recorded in Gene Bank with numbers KC991027 and KF015727. 223 and 240 polymorphic loci were detected in Sardabrud and Astara River that all of them were out of Hardy-Weinberg equilibrium (p<0.05). Average nucleotide and haplotype diversity were 0.127±0.067, 1.000±0.005 in Sardabrud River and 0.118±0.063 and 1.000±0.005 in Astara River

Investigation on genetic structure of Russian sturgeon (Acipenser gueldenstaedtii) populations of the north (Volga River) and south Caspian Sea (coasts of Iran and Turkmenistan) using microsatellite techniques

A total of 28 specimens of adult Russian sturgeon brood fish from the Volga River (Astrakhan, Russia) and 42 specimens from the south Caspian Sea (coastline of Iran and Turkmenistan) were collected. About 2g of fin tissue was stored in 96% ethyl alcohol and transferred to the genetic laboratory of the International Sturgeon Research Institute. Genomic DNA was extracted using phenol-chloroform method. The quality and quantity of DNA was assessed by Agarose gel electrophoresis and spectrophotometry. Polymerase Chain Reaction (PCR) was conducted using eight pairs of microsatellite primers and its products were electrophoresed using 6% polyacrylamide gel followed by silver nitrate staining. Allele sizes were measured in all populations, then genetic parameters were calculated using Gen Alex program and the phylogenetic relationship was determined and drawn using TFPGA program. A minimum of 10 and a maximum of 21 alleles were identified per locus and the observed heterozygosity ranged between 0.50-0.96 and the expected heterozygosity was 0.74-0.90 with an average of 0.68. Hardy-Weinberg equilibrium was observed at Ls-19, Ls-39 loci, but showed disequilibrium in other loci. FST index between Volga and South Caspian Sea samples was 0.031. The genetic similarity and distance was 0.661 and 0.414, respectively. Results of the present investigation indicate that there are no significant differences between the south Caspian Sea Russian sturgeon specimens

Facilitators of implementing occupation based practice among Iranian occupational therapists: A qualitative study

Background: The Occupation-Based Practice (OBP) is a central core of occupational therapy (OT).It refers to using a meaningful occupation based on the client's interests, needs, health and participation in daily life. This study aimed to explore the facilitators of implementing OBP among Iranian occupational therapists. Methods: Fourteen occupational therapists participated in this study. Data were collected through semi-structured interviews, and the sampling method was purposeful. The interviews were continued until data saturation was reached, and data were recorded and transcribed verbatim. Data were analyzed through qualitative content analysis using constant comparative analysis. Results: Our analysis explored two themes: Factors attributed to context, and factors attributed to therapists. The first theme consisted of three subthemes: Educational programs of OT department, public information about OBP and clinical setting compatible with OBP. The second theme also contained three subthemes including: Positive attitude regarding effectiveness of OBP, emphasis on client- centered and family- centered practice and convincing the clients to utilize OBP. Conclusion: The facilitators of implementing OBP are attributed to factors internal to the therapists as well as to issues in the external environment and context. Understanding these factors will help occupational therapists, OT educational staff, administrators and rehabilitation team members to facilitate the implementation of OBP

Optimum conditions for protein extraction from tuna processing by-products using isoelectric solubilization and precipitation processes

The by-product from tuna processing is a potential source of edible protein. Therefore, it is very important to extract protein from such raw materials for human food. In this study the optimum pH for protein extraction from tuna by-products was optimized by using isoelectric solubilization and precipitation processes. The Response Surface Methodology (RSM) and the single factor model were used for optimization of the protein extraction process. From ANOVA (one-factor design) tests, significant effects were detected for process variables, functional properties and stability between tuna protein isolate prototypes extracted at acidic and alkaline pH, the latter having the least Total Volatile Basic Nitrogen (TVB-N) and Thiobarbituric Acid Reactive Substances (TBARS), but the highest Water Holding Capacity (WHC), hardness, cohesiveness, springiness and viscosity values. The highest yield percentage was found for the alkaline aided process, too. The alkali-aided process recovered proteins of higher whiteness than the acid-aided process. Accordingly the optimum pH of protein extraction was obtained. The model was then validated and maximized based on the functional properties, stability and recovery yield data. Under the optimized pH, the experimental values were in good agreement with those predicted by the software. Then the properties of the optimum prototypes were compared to the fish protein isolated from different by-products. The results suggest that the proteins recovered from tuna processing by-products could be a valuable source of protein ingredient for fortification/ developing formulated ready-to-eat products

Canine distemper virus neutralization activity is low in human serum and it is sensitive to an amino acid substitution in the hemagglutinin protein

© 2015 Elsevier Inc.Serum was analyzed from 146 healthy adult volunteers in eastern Africa to evaluate measles virus (MV) and canine distemper virus (CDV) neutralizing antibody (nAb) prevalence and potency. MV plaque reduction neutralization test (PRNT) results indicated that all sera were positive for MV nAbs. Furthermore, the 50% neutralizing dose (ND50) for the majority of sera corresponded to antibody titers induced by MV vaccination. CDV nAbs titers were low and generally were detected in sera with high MV nAb titers. A mutant CDV was generated that was less sensitive to neutralization by human serum. The mutant virus genome had 10 nucleotide substitutions, which coded for single amino acid substitutions in the fusion (F) and hemagglutinin (H) glycoproteins and two substitutions in the large polymerase (L) protein. The H substitution occurred in a conserved region involved in receptor interactions among morbilliviruses, implying that this region is a target for cross-reactive neutralizing antibodies

The effects of different concentrations of probiotic Saccharomyces cerevisia on growth performance and survival rate of rainbow trout (Oncorhynchus mykiss), fry and resistance against salinity

In the present study, a yeast strain Saccharomyces cerevisia var. elipsoidous, acting as probiotic, was administered to rainbow trout (Oncorhynchus mykiss Walbaum, 1792) fry during a period of 21 days and the effects of the yeast on improvement of growth and resistance against environmental stress were evaluated with respect to fish fed on yeast free feed (control group). The control treatment consisted of a standard commercial diet, and the treatments consisted of the control diet supplemented with 0, 1, 5 and 10% yeast (w/w). The results demonstrate the beneficial effects of probiotics on the characteristics of rainbow trout, as the Specific Growth Ratio (SGR), body weight gain (%BWG) and protein conversion ratio (PER) in 5% yeast-fed fish were significantly (P&lt;0.05) enhanced by probiotic administration. On the contrary, no effect on the fry growth performance, mortality, condition factor (CF), food conversion ratio (FCR) and histological assessment was shown. A significant (P&lt;0.05) increase in lipid content of the carcass was detected in diets with probiotic compareD to 0% and the control treatments. Ash and protein contents of the carcass increased and decreased with an increase in yeast amount, respectively. Challenge with different levels of salinity (10 and 15 ppt) after 24 h revealed 100% survival in treatments containing yeast as probiotic, and difference with control group was significant (p&lt;0.05) indicating that S. cerevisia could enhance the resistance against salinity stress. Addition of yeast in concentration of 5% to the diet is recommended during the early period of rainbow trout fry farming to achieve the best results on growth performance and feed efficiency.Keywords: Saccharomyces cerevisia var. elipsoidous, Oncorhynchus mykiss, probiotic, survival and growth rate, carcass qualityAfrican Journal of Biotechnology, Vol. 13(10), pp. 1160-1168, 5 March, 201

Host genetics and viral load in primary HIV-1 infection: clear evidence for gene by sex interactions

© 2014, The Author(s).Research in the past two decades has generated unequivocal evidence that host genetic variations substantially account for the heterogeneous outcomes following human immunodeficiency virus type 1 (HIV-1) infection. In particular, genes encoding human leukocyte antigens (HLA) have various alleles, haplotypes, or specific motifs that can dictate the set-point (a relatively steady state) of plasma viral load (VL), although rapid viral evolution driven by innate and acquired immune responses can obscure the long-term relationships between HLA genotypes and HIV-1-related outcomes. In our analyses of VL data from 521 recent HIV-1 seroconverters enrolled from eastern and southern Africa, HLA-A*03:01 was strongly and persistently associated with low VL in women (frequency = 11.3 %, P  0.50). In a reduced multivariable model, age, sex, geography (clinical sites), previously identified HLA factors (HLA-B*18, B*45, B*53, and B*57), and the interaction term for female sex and HLA-A*03:01 collectively explained 17.0 % of the overall variance in geometric mean VL over a 3-year follow-up period (P < 0.0001). Multiple sensitivity analyses of longitudinal and cross-sectional VL data yielded consistent results. These findings can serve as a proof of principle that the gap of “missing heritability” in quantitative genetics can be partially bridged by a systematic evaluation of sex-specific associations

Fluctuation of gonadosomatic index during oocyte development in the narrow-clawed crayfish Astacus leptodactylus (Eschscholtz, 1823) in Aras Dam Lake, Iran

This study was carried out with the aim of examining the seasonal reproductive cycle of the female crayfish Astacus leptodactylus from Aras Dam Lake, Western-Azerbaijan, Iran. Gonadosomatic index (GSI), and oocyte size were measured in females sampled seasonally in June, August, November (2011), January (2012). Development of the oocytes was categorized according to the diameter and the presence/absence of yolk granules. The ovary development was accompanied by increasing levels gonadosomatic index and egg diameter. Ovarian development histologicaly related to the seasonal GSI . This index was low in June (0.61±0.05) when oocytes started developing and reached the highest value in November (13.53±0.25), when vitellogenic oocytes were abundant in the mature ovary. Our results highlight the relationship between the ovary development and the GSI and egg diameter in the crayfish A. leptodactylus during the reproductive cycle and held important implications for the management of aquatic species. Thus, investigation of female A. leptodactylus reproduction is highly significant for fisheries managers as well as environmentalists concerned with perpetuating crayfish stocks