Additional Selenium Research Articles

Comparative Evaluation of Yeast Selenium and Sodium selenite Supplementation on Fertility, Hatchability and Antioxidant Status in Dual Purpose Laying Hens

Selenium (Se) is an essential trace element, involved in many biological processes in animals, such as antioxidant status, reproduction, immunity, reproduction, and thyroid hormone metabolism. Dual purpose Giriraja (180) hens of 30 weeks of age were randomly distributed into 4 treatment groups having 5 replicates of 10 (1 male + 9 females) birds each. Treatment groups were divided based on additional selenium supplementation to the basal diet. Accordingly, the basal diet was T1, with further addition of sodium selenite, sodium selenite + selenium-enriched yeast and selenium enriched yeast @ 0.5, 0.3 + 0.2, and 0.5 mg Se/kg basal diet to form diets for T2, T3, and T4, respectively. The experimental period was for 8 weeks @ 150g feed/day/bird. Fertility, hatchability and antioxidant status viz., levels of Glutathione peroxidase, Superoxide dismutase and Catalase were assessed. The addition of different sources of Se alone and their combination did not show any significant difference in fertility and hatchability parameters at the end of 4th and 8th weeks of the study. Similarly, no significant improvement was seen in the antioxidant status of the birds at the end of the experiment. In conclusion, the requirement of selenium, in layer (0.05-0.08mg/kg diet) can be met with the amount of Se present in the feed raw material. Hence additional selenium supplementation may not be required under normal environment and production conditions.

Antioxidant system of the body of young Ukrainian beef cattle under the action of microelements

Active forms of oxygen are formed in the course of the organism's vital activity in biochemical reactions. These forms, when the pro/antioxidant balance is disturbed, trigger a cascade of lipid peroxidation, which can be the cause of the development of various pathological conditions. To prevent the negative influence of lipid peroxidation products in the body, a powerful antioxidant system is activated. This system consists of an enzymatic and a non-enzymatic link. An important aspect of the normal functioning of this system is the provision of the body with important trace elements. A number of minerals are included in the active center of antioxidant enzymes or have an effect on the reactions of non-enzymatic antioxidants. Research was conducted on fattening bulls of the Ukrainian meat breed. During the monitoring of microelements in feed, it was found that the vast majority of farm feed was deficient in copper, selenium and manganese and for this reason the animals consumed an insufficient amount of these minerals. These data were confirmed by the low content of these trace elements in blood serum. The addition of inorganic salts of microelements to the basic diet led to an increase in the concentration of copper, manganese and selenium in the blood serum by 20.5%, 37.3% and 23.9%. The study of the content of lipid peroxidation products showed that during the 30 days of the experiment, the level of lipid hydroperoxide increased by 25.5%, diene conjugates by 22.8%, and malonic dialdehyde by 22.0%. This indicates that against the background of increased age-related metabolism in the body of young animals, the oxidation-reduction reactions that are a predictor of the start of peroxidation processes increase. It was also noted that with a deficiency of certain trace elements, the activity of both the enzymatic and non-enzymatic links of the antioxidant system was reduced. Thus, in 30 days, the level of catalase, superoxide dismutase, and glutathione peroxidase decreased by 9.4%, 15.3%, and 13.0%, respectively. During this time, the content of tocopherol and ceruloplasmin decreased by 16.8% and 9.8%. Additives also had a positive effect on the activity of the antioxidant system by increasing its components. Additives of trace elements had different effects on the activity of antioxidant enzymes. The greatest effect on the level of catalase and superoxide dismutase was observed when copper salts were added, when the increase of these enzymes was noted by 1.11 and 1.23 times, respectively. Accordingly, the level of glutathione peroxidase was the highest in animals that received additional selenium – 1.21 times. The addition of copper also had the greatest biological effect on the important non-enzymatic component of antioxidant protection – ceruloplasmin. Its level increased by 1.24 times under the action of copper sulfate. The level of tocopherol was higher under the action of manganese, when its concentration was 1.11 times higher than the control. Against this background, there was a decrease in the products of lipid peroxidation: lipid hydroperoxides – 1.19 times under the action of selenium; diene conjugates – by 1.22 times and malonіс dialdehyde – by 1.11 times under the influence of copper and manganese compounds, respectively.

Selenium Protects Mouse Hypothalamic Cells from Glucocorticoid-Induced Endoplasmic Reticulum Stress Vulnerability and Insulin Signaling Impairment

The use of glucocorticoid medications is known to cause metabolic side effects such as overeating, excess weight gain, and insulin resistance. The hypothalamus, a central regulator of feeding behavior and energy expenditure, is highly responsive to glucocorticoids, and it has been proposed that it plays a role in glucocorticoid-induced metabolic defects. Glucocorticoids can alter the expression and activity of antioxidant enzymes and promote the accumulation of reactive oxygen species. Recent evidence indicates that selenium can counter the effects of glucocorticoids, and selenium is critical for proper hypothalamic function. This study sought to determine whether selenium is capable of protecting hypothalamic cells from dysfunction caused by glucocorticoid exposure. We treated mHypoE-44 mouse hypothalamic cells with corticosterone to study the effects on cellular physiology and the involvement of selenium. We found that corticosterone administration rendered cells more vulnerable to endoplasmic reticulum stress and the subsequent impairment of insulin signaling. Supplementing the cell culture media with additional selenium alleviated endoplasmic reticulum stress and promoted insulin signaling. These findings implicate a protective role of selenium against chronic glucocorticoid-induced hypothalamic dysfunction.

Effects of selenium supplementation on the growth performance, slaughter characteristics, and blood biochemistry of naked neck chicken

This study examined how selenium-supplemented diets affected the performance of naked neck chickens. The birds were fed both organic and inorganic selenium at 0.30 ppm, while the control diet did not include any additional selenium. A total of 225 one-day-old naked neck chicks were randomly divided into 3 experimental groups, each of which was replicated 5 times (replicates) and contained 15 birds. This was done using a completely randomized design. The data was collected after growth, meat quality, and blood profile parameters were assessed. The findings showed that the birds fed inorganic selenium in the diet displayed increased (P < 0.05) feed intake followed by those administered organic selenium and the control diet. On the other hand, birds fed organic selenium in the diet showed enhanced body weight gain and better feed conversion ratio (P < 0.05). Similarly, organic selenium supplementation increased (P < 0.05) breast and thigh weight compared to inorganic selenium, but no other metrics, such as dressing percentage, drumstick weight, liver weight, gizzard weight, heart weight, or wing weight, significantly differed between treatments (P > 0.05). When compared to birds fed inorganic Se and control diet, the birds fed organic Se had greater (P < 0.05) blood levels of total protein and globulin. Additionally, it was discovered that organic Se-fed birds had greater (P < 0.05) blood Se concentrations than control and inorganic Se-fed birds. However, no differences between treatments were found in albumin, glucose, cholesterol, triglycerides, or uric acid (P > 0.05). In conclusion, adding Se-enriched yeast, as an organic selenium source, to diets may enhance the poor growth and slaughter characteristics of naked neck chicks without negatively affecting blood chemistry.

METHODS OF ANALYTICS OF BIG DATA OF POPULAR ELECTRONIC NEWSPAPERS ON FACEBOOK

Due to the popularity of social networks, all famous brands use them to promote and support their product. For example, well-known foreign newspapers such as: Washington Post, New York Times, Time, Reuters, Forbes duplicate information about news on the Facebook social network for greater readership. Using methods of automated data collection from web pages, a list of posts is formed based on which data analysis is performed. Statistical results of frequency, popularity of certain articles, audience reach and people's reaction to posts are obtained from a large volume of data. In the Java programming language and using additional Selenium, JavaFX libraries, all processes for data normalization is developed and data visualization is used. In addition, the dependence of the post coverage of newspaper editions on the number of posts published during the day is investigated in Facebook social network. The work also examines the most popular posts and their topics. The relationship between keywords and real events is analyzed. Keywords : big data, social networks, data analytics, automated data collection, data processing.

Effect of Se-Enriched Irrigation Water on the Biomass Production and Elemental Composition of Green Bean, Cabbage, Potato and Tomato.

Additional Selenium (Se) intake may be recommended in areas of Se deficiency to prevent various human diseases. One possibility for this is biofortification. In this experiment, the effect of irrigation water containing 100 and 500 µg L−1 Se, in the form of Na2SeO4, on green bean, cabbage, potato and tomato was investigated in a greenhouse pot experiment with sand, silty sand and silt soils. The chlorophyll content index was usually improved by Se and was significantly higher in potato in sand and silty sand and in tomato in silty sand and silt soils. The Se content of edible plant parts increased 63-fold in the 100 µg L−1 Se treatment and almost 400-fold in the 500 µg L−1 Se treatment, averaged over the four species and the three soils. Irrigation water with a Se content of 100 µg L−1 may be suitable for the production of functional food in the case of green beans, potatoes and tomatoes. However, due to its greater Se accumulation, cabbage should only be irrigated with a lower Se concentration. The use of Se-enriched irrigation water might be a suitable method for Se biofortification without a significant reduction in plant biomass production and without a remarkable modification of other macro- and microelement contents.

The use of Saccharomyces cerevisiae fermented coconut dregs with the addition of sodium selenite as a source of selenium in broiler diets

Fermentation has been practised in feed technology to bioconvert the inorganic minerals to organic compounds. A study was done to determine the effect of Saccharomyces cerevisiae fermented coconut dregs with the addition of selenium on growth performance, feed digestibility and the intestinal response of broiler chickens. The study used 112-day old unsexed broiler chicks for 6 weeks. The broilers were fed with 4 different experimental diets. The diets were basal diet (T1), basal diet plus 0.5% coconut dregs (T2), basal diet plus 0.5% of 5 days fermented coconut dregs (T3) and basal diet plus 0.5% of 7 days fermented coconut dregs (T4). The broilers were fed ad libitum and tap water was offered at all times. The broiler chicks were vaccinated against New Castle Diseases on the fourth day. Feeders and drinkers were placed inside the pen. The feeders, drinkers, pens and surroundings were cleaned whenever necessary. A completely randomized design was used in this study with four different treatment diets, four replicate cages of 7 birds each. The data found in this study was analyzed using an analysis of variance. A Tukey test was applied once a significant effect was detected in the analysis of variance. Results of the study indicate that body weight gain and dry matter digestibility increased when the birds were fed the diets T3 and T4. The relative gizzard weight of birds fed the T3 and T4 was lighter than the birds fed the T1 and T2. Feed intake, feed conversion ratio, carcass percentage and relative intestine weight were not affected by the experimental diets. In conclusion, feeding the birds with diets supplemented with Saccharomyces cerevisiae-fermented coconut dregs with additional selenium improved feed quality and broiler performance.

The Effect of Dietary Supplementation with Inorganic or Organic Selenium on the Nutritional Quality and Shelf Life of Goose Meat and Liver.

Simple SummaryGeese have a unique ability among aquatic poultry species to efficiently utilize high-fiber feedstuffs, however research investigating concentrate feeding strategies in the farm setting is limited. This experiment investigated the effect of dietary supplementation with inorganic or organic selenium on nutritional quality and shelf life of goose meat and liver samples. Differences between geese supplemented with I-Se and O-Se were detected for several parameters, yet these differences were less tangible than those between geese not supplemented with additional selenium (CON) and geese supplemented with additional selenium (I-Se and O-Se). Overall, it was concluded that supplementation with additional dietary selenium in both the inorganic and organic forms improved nutritional quality and shelf life of goose meat and liver samples.Ninety-six male goslings were allocated and assigned to treatment using a completely randomized design. Dietary treatments included a basal diet consisting of corn, wheat, and soybean meal with either no additional selenium (CON), 0.3 mg/kg of inorganic selenium (I-Se; sodium selenite), or 0.3 mg/kg of organic selenium (O-Se; selenium-enriched yeast). After a 56-day feeding period, geese were slaughtered on a common ending day and two geese per pen (n = 24) were used for the analyses conducted in this study. Meat (equal portions of the breast and thigh meat) and liver were collected and evaluated for proximate composition, fatty acid profile, pH, phenolic content, thiobarbituric acid reactive substances (TBARS), and total volatile basic nitrogen (TVB-N) over a 9-day storage period at 4 °C. The meat and liver samples from geese supplemented I-Se or O-Se had greater (p < 0.01) lipid content compared with geese not supplemented with additional selenium. At the conclusion of the 9-day storage period, meat and liver samples from geese supplemented I-Se or O-Se had lower (p < 0.05) pH values, greater (p < 0.05) phenolic content, lower (p < 0.05) TBARS values, and lower (p < 0.05) TVB-N compared with geese not supplemented with additional selenium (CON).

Association of dietary and serum selenium concentrations with glucose level and risk of diabetes mellitus: A cross sectional study of national health and nutrition examination survey, 1999-2006

BackgroundThe associations among dietary selenium intake, serum selenium concentration, plasma glucose and glycosylated hemoglobin levels, and diabetes risk remain controversial. This study aimed to evaluate these associations in adults from the United States. MethodsWe conducted a cross-sectional study of participants aged 18 years and older who participated in the National Health and Nutrition Examination Survey. Between 1999 and 2006, a total of 41,474 participants were initially included in this study. Multivariable linear or logistic regression analysis was used to investigate the association between dietary selenium intake and serum selenium concentrations, glucose level, and diabetes risk. ResultsThe average age of the participants was 30.32 ± 23.95 years, and 48.72 % were men. Their mean dietary selenium intake and mean serum selenium concentration were 98 ± 55 μg per day and 129 ± 22 ng/mL, respectively. Compared with t he lowest quartile of dietary selenium intake, the highest quartile was associated with elevated plasma glucose levels (β = 2.412, 95 % confidence interval [CI]: 0.420, 4.403, P = 0.018), glycosylated hemoglobin levels (β = 0.080, 95 % CI: 0.041, 0.119, P < 0.001), and diabetes risk (odds ratio [OR] = 2.139, 95 % CI: 1.763, 2.596, P < 0.001). Higher serum selenium was also associated with increased plasma glucose levels (β = 12.454, 95 % CI: 4.122, 20.786, P = 0.003) and glycosylated hemoglobin levels (β = 0.326, 95 % CI: 0.187, 0.465, P < 0.001). A generalized additive model with a spline curve suggested a nonlinear relationship between dietary selenium intake, serum selenium and glucose levels, and diabetes risk. ConclusionsDietary selenium intake and serum selenium were positively associated with elevated levels of plasma glucose and glycosylated hemoglobin, and the relationships were nonlinear. Additional selenium supplementation for patients with diabetes may not be recommended.

Form of Supplemental Selenium in Vitamin-Mineral Premixes Differentially Affects Early Luteal and Gestational Concentrations of Progesterone, and Postpartum Concentrations of Prolactin in Beef Cows.

Simple SummarySoils with inadequate levels of selenium are widespread in the northwest, northeast, and southeast USA. Therefore, dietary supplementation of forage-grazing beef cattle with additional selenium is recommended in these regions for optimal growth, immune function, and fertility. We have reported that the form of selenium provided to Angus-cross cows can affect circulating concentrations of progesterone on day 6 of the estrous cycle, a time when increased progesterone is known to promote fertility. Hence, we sought to confirm this initial finding, determine the effect of the form of selenium on peripheral concentrations of progesterone during gestation, and determine the effect of the form of selenium on circulating concentrations of prolactin during lactation. Cows were supplemented with equimolar amounts of either an inorganic form, or a 1:1 mixture of inorganic and organic forms of selenium throughout this study. We confirmed our original finding that the mixed (1:1 inorganic to organic selenium) supplement increased systemic progesterone in the early luteal phase of the estrous cycle, and determined that cows maintained on this same supplement had elevated concentrations of progesterone throughout gestation. Interestingly, these same cows revealed a treatment-induced decrease in systemic prolactin during late lactation. The form of selenium provided to cows can be manipulated to affect reproductive responses and offers a viable management tool to improve fertility in cows in regions with selenium-deficient soils.Soils with marginal to deficient levels of selenium (Se) are widespread in the northwest, northeast, and southeast US. Supplementation to the diet of forage-grazing beef cattle with a vitamin-mineral mix containing additional Se is recommended in these geographic regions. We have reported that the form of supplemental Se provided to Angus-cross beef cows can affect circulating levels of progesterone (P4) on day 6 of the estrous cycle, a time when increased P4 is known to promote fertility. The objectives of this study were to (1) confirm and expand upon our initial report that the form of Se provided to cows affects early luteal-phase concentrations of systemic P4, (2) determine the effects of the form of Se on concentrations of P4 during gestation, and (3) determine the effects of the form of Se on concentrations of prolactin (PRL) during lactation. Throughout this study, Angus-cross beef cows had ad libitum access to a vitamin-mineral mix containing 35 ppm of Se in either an inorganic form (ISe) or a 1:1 mix of inorganic and organic forms (MIX). We observed a MIX-induced increase (p = 0.006) in systemic concentrations of P4 on day 7 but not on days 4 or 10 of the estrous cycle, consistent with our earlier report. We observed a MIX-induced increase (p = 0.02) in the systemic concentration of P4 at months 1, 3, 5, and 7 of gestation, and a MIX-induced decrease (p < 0.05) in systemic concentrations of PRL at months 5 and 6 of lactation. In summary, the form of Se provided to cows can be manipulated to affect the early luteal phase and gestational concentrations of P4, and postpartum concentrations of PRL.

Selenium prevents lithium accumulation and does not disturb basic microelement homeostasis in liver and kidney of rats exposed to lithium.

Lithium has been used in medicine for almost seventy years. Besides beneficial effects, its therapy may cause serious side-effects, with kidney and liver being the organs most vulnerable to its harmful influence. Therefore, research on protective agents against lithium toxicity has been continuing for some time. The aim of the present study is to evaluate the influence of additional selenium supplementation on lithium content, as well as homeostasis of the essential microelements iron, zinc, copper and manganese in kidney and liver of rats undergoing lithium exposure. The study was performed on 4 groups of male Wistar rats (6 animals each) treated with: control - saline; Li-group - Li2CO3 at a dose of 2.7 mg Li/kg b.w.; Se-group - Na2SeO3 at a dose of 0.5 mg Se/kg b.w.; Li+Se-group - both Li2CO3 and Na2SeO3 at doses of 2.7 mg Li/kg b.w. and of 0.5 mg Se/kg b.w., respectively, in the form of water solutions by stomach tube, once a day for 3 weeks. The content of the studied elements in the organ samples was determined using flame atomic absorption spectroscopy (FAAS). Lithium administered alone caused a significant increase in its content in liver and kidney. Additional supplementation with selenium reversed these effects, and did not markedly affect other studied microelements compared to control. The obtained results suggest that selenium could be regarded as an adjuvant into lithium therapy. However, considering the limitations of the present study (the short duration, using only one dose and form of selenium) the continuation of the research seems to be necessary to clarify the influence of selenium supplementation on basic microelements and lithium accumulation in organs during lithium exposure.

Transcriptional profiling of Auricularia cornea in selenium accumulation

Auricularia cornea is a widely cultivated edible fungus with substantial nutritive value. This study aimed to enrich the multifunctional bionutrient element selenium in A. cornea to improve its quality and explore the accumulation of selenium in the fungus using high-throughput RNA-Seq technology. In general, the treatment group with a 100 µg/g supply of selenium outperformed the other treatment groups in terms of high yield, rich crude polysaccharides and a high total selenium concentration. Additional evidences demonstrated the budding and mature phases were two typical growth stages of A. cornea and were important for the accumulation of selenium. Therefore, the budding and mature phase tissues of A. cornea in the treatment group with a 100 µg/g supply of selenium were used for transcriptome analysis and compared to those of a control group that lacked additional selenium. A total of 2.56 × 105 unigenes from A. cornea transcriptome were assembled and annotated to five frequently used databases including NR, GO, KEGG, eggNOG and SwissProt. GO and KEGG pathway analysis revealed that genes involved in metabolic process and translation were up-expressed at the budding stage in response to selenium supplementation, including amino acid metabolism, lipid metabolism, ribosome. In addition, the differential gene expression patterns of A. cornea suggested that the up-expressed genes were more likely to be detected at the budding stage than at the mature stage. These results provide insights into the transcriptional response of A. cornea to selenium accumulation.

A pilot study on the beneficial effects of additional selenium supplementation to methimazole for treating patients with Graves’ disease

Background/aim The aim of this study was to assess the effect of a combination use of methimazole (MMI) and selenium (Se) in the treatment of Graves’ disease (GD). Materials and methods A total of 103 newly diagnosed hyperthyroidism patients were randomized to MMI and MMI + Se combination groups. After treatment for 6 months, the levels of triiodothyronine (FT3), free thyroxine (FT4), thyrotropin receptor antibody (TRAb), thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TGAb) were observed. An in vitro culture model of thyroid cells was established and the protein expression and mRNA levels of TRAb, TPOAb, and TGAb were determined by western blot and RT-PCR.Results A significant decrease in the levels of FT3, FT4, TRAb, TPOAb, and TGAb were observed in both groups along with a marked increase in TSH levels. Furthermore, the in vitro experiments showed that the protein expression and mRNA levels of TRAb, TPOAb, and TGAb decreased significantly. Also, compared to the MMI group, there was a greater improvement of these indices in the MMI + Se group. Conclusion We suggest that the combined use of MMI and Se could improve the thyroid activity in patients, which may provide an effective therapy for the treatment of GD in clinical settings.

Glutathione as an antioxidant marker: determination of glutathione concentration in the breast muscles and liver of broilers supplemented with different selenium sources

The aim of the study was to determine the influence of different selenium sources on antioxidant properties. The glutathione (GSH) concentration and glutathione peroxidase (GPx) activity were measured in the breast muscles and liver of 60 one-day-old broiler chickens. Another goal was to compare these indices with the weights of individual tissues and the live weight of broilers. The broilers were divided into 4 groups according to the selenium source: group 1 (control), group 2 (selenized yeast), group 3 (selenomethionine), group 4 (sodium selenite). Treatment groups were supplemented with 0.2 mg of additional selenium/kg. No significant changes in the hepatic GSH concentrations (P&gt; 0.05) were found in the experimental groups compared to control. Significantly higher GSH concentration (P&lt; 0.05) was found in breast muscles of broilers in group 4 (sodium selenite) compared to control. However, no positive effect of selenium supplementation in the form of sodium selenite was observed. The differences in the GPx activity in breast muscles and liver between the experimental groups and the control group were not significant (P&gt; 0.05). No significant differences were recorded in the experimental groups compared to control in relation to the GSH concentration and GPx activity measured in the tissues. A significantly positive correlation was noted between mean GPx activity in breast muscle and breast muscle weight (P&lt; 0.01; r = 0.3790) and live weight (P&lt; 0.05; r = 0.2690). Although changes in the GSH concentration and GPx activity were recorded in some experimental groups, the selected dose of additional selenium appeared to be too low to affect these concentrations and the antioxidant defence system.

Dietary supplementation of selenium yeast enhances the antioxidant capacity and immune response of juvenile Eriocheir Sinensis under nitrite stress

This study elucidates the response to nitrite stress and the effect of dietary selenium supplements on the growth, antioxidant activity, immunity and transcriptome of juvenile Chinese mitten crab Eriocheir sinensis. In the control group, the crabs were fed the diet without selenium supplementation and there was no nitrite addition to the water. In the test group, the crabs were fed diets with three levels of selenium 0 (N1), 0.5 (N2) and 1.0 (N3) mg/kg in the water containing 2 mg/L NO2N as a stress factor for eight weeks. Feed conversion ratio (FCR) was improved by adding dietary selenium. There was no significant difference in specific growth rate and weight gain between N1 and the control groups, or among different selenium levels in the test group. The superoxide dismutase (SOD) activity was significantly lower, but malondialdehyde (MDA) was higher in the N1 group than those in the serum and hepatopancreas of the control group. The activities of SOD, glutathione peroxidase (GPx) and acid phosphatase increased at the medium level of selenium but decreased as the level of dietary selenium increased to 1.0 mg/kg. The serum lysozyme (LZM) activity increased but the MDA content in both serum and hepatopancreas decreased with the increase of selenium levels. The total clean reads of the crabs in the control group, N1 and N3 groups reached 390.7M and were assembled into 106 471 transcripts. Compared with the control group, 1196 gene were significantly expressed (588-up and 608-down) in the N1 group under nitrite stress. Between the N1 and N3 groups, the expression of 1537 genes (751-up and 786-down) were significantly different. KEGG pathway analysis reveals that 11 and 19 pathways were significantly different between N1 and control and between N3 and N1 groups, respectively. Transcriptome results demonstrate that nutrient metabolism is much more active in crabs fed additional selenium under nitrite stress. This study indicates that dietary selenium can improve both antioxidant capacity and immune response and alter the protein and carbohydrate metabolism of E. sinensis under nitrite stress.

Room temperature pulsed-DC sputtering deposition process for CIGS absorber layer: Material and device characterizations

A pulsed-DC sputtering process at room temperature has been developed for the deposition of the CIGS absorber layer. It uses a single quaternary target and is followed by a high temperature post-deposition annealing process. It has to be particularly noticed that no additional selenium supply was used. The annealed layers have shown a high microstructural quality: micrometric grain size, highly oriented (112) chalcopyrite phase, no phase decomposition and no Cu2-xSe secondary phase at the surface. The use of such an absorber layer for the fabrication of 0.5 cm2 solar cells has allowed reaching a conversion efficiency of 11.8% with an open circuit voltage of 558 mV, a short circuit current density of 32.1 mA·cm−2 and a fill factor of 65.8%.

Lithium disturbs homeostasis of essential microelements in erythrocytes of rats: Selenium as a protective agent?

Selenium is an essential element which shows protective properties against diverse harmful factors. Lithium compounds are widely used in medicine, but, in spite of undoubted beneficial effects, treatment with these compounds may lead to severe side effects, including renal, gastrointestinal, neurological, endocrine and metabolic disorders. This study was aimed at evaluating the influence of selenium and/or lithium on lithium, iron, zinc and copper content in rats' erythrocytes as well as estimate the action of additional selenium on lithium exposure effects. The experiment was performed on four groups of rats (six animals each): control - received saline; Li - received 2.7mg Li/kg b.w. as lithium carbonate; Se - received 0.5mg Se/kg b.w. as sodium selenite; Se+Li - received simultaneously 0.5mg Se/kg b.w. and 2.7mg Li/kg b.w. (sodium selenite and lithium carbonate). The administration was performed for three weeks, once a day by stomach tube, in form of water solutions. In erythrocytes the content of lithium, iron, zinc and copper was determined using flame atomic absorption spectroscopy. Lithium treatment insignificantly disturbed iron and zinc homeostasis as well as markedly increased lithium accumulation and copper content in rat erythrocytes. Selenium coadministration reversed those effects. The beneficial effect of selenium on disturbances of studied microelements homeostasis as well as on preventing lithium accumulation in erythrocytes in Li receiving animals allows suggesting that further research on selenium application as an adjuvant in lithium therapy is worth carrying on.

Effect of Selenium on Lipid and Amino Acid Metabolism in Yeast Cells

This article discusses the effect of selenium in aqueous solutions on aspects of lipid and amino acid metabolism in the cell biomass of Saccharomyces cerevisiae MYA-2200 and Candida utilis ATCC 9950 yeasts. The yeast biomass was obtained by using waste products (potato wastewater and glycerol). Selenium, at a dose of 20 mg/L of aqueous solution, affected the differentiation of cellular morphology. Yeast enriched with selenium was characterized by a large functional diversity in terms of protein and amino acid content. The protein content in the biomass of S. cerevisiae enriched with selenium (42.6%) decreased slightly as compared to that in the control sample without additional selenium supplementation (48.4%). Moreover, yeasts of both strains enriched with selenium contained a large amount of glutamic acid, aspartic acid, lysine, and leucine. Analysis of fatty acid profiles in S. cerevisiae yeast supplemented with selenium showed an increase in the unsaturated fatty acid content (e.g., C18:1). The presence of margaric acid (C17:0) and hexadecanoic acid (C17:1) was found in the C. utilis biomass enriched with selenium, in contrast to that of S. cerevisiae. These results indicate that selenium may induce lipid peroxidation, which consequently affects the loss of integrity of the cytoplasmic membrane. Yeast enriched with selenium with optimal amino acid and lipid composition can be used to prepare a novel formula of dietary supplements, which can be applied directly to various diets for both humans and animals.

Tin and Lead Phosphanido Complexes: Reactivity with Chalcogens.

The reactivity of tin and lead phosphanido complexes with chalogens is reported. The addition of sulfur to [(BDI)MPCy2] (M = Sn, Pb; BDI = CH{(CH3)CN-2,6-iPr2C6H3}2) results in the formation of phosphinodithioates [(BDI)MSP(S)Cy2] regardless of the conditions; however, when selenium is added to [(BDI)MPCy2], a selenium insertion product, phosphinoselenoite [(BDI)MSePCy2], can be isolated. This compound readily reacts with additional selenium to form the phosphinodiselenoate complex [(BDI)MSeP(Se)Cy2]. In contrast, the addition of selenium to [(BDI)SnP(SiMe3)2] results in the formation of the heavy ether [(BDI)SnSeSiMe3]. Differences in the solution and solid-state molecular species of tin phosphinoselenoite and phosphinodiselenoate complexes were probed using multinuclear solution and solid-state NMR spectroscopy.

Electron transport properties of thermoelectrics based on layered substituted transition metal dichalcogenides

Temperature dependences of the electrical conductivity are studied in the range 4.2’300 K and Seebeck coefficient at room temperature of bulk samples of tungsten dichalcogenide polycrystals with niobium substitutions for tungsten and selenium substitutions for sulfur – W1–x Nb x (S1–y Se y )2. The two-dimensionalization of electron transport properties is detected at niobium concentrations x ≥ 0.1 in W1–x Nb x S2 and x ≥ 0.05 in W1–x Nb x Se2. In samples with additional partial selenium substitution for sulfur the electron transport remains three-dimensional. At room temperature the Seebeck coefficient (at equal electrical conductivities) is several times higher in the samples with quasi-two-dimensional transport than in the samples with three-dimensional transport. The calculation of the power factor at room temperature shows its nine times increase.