Increasing Se Content Research Articles

Quality, nutrient and sensory characteristics of aged meat from lambs supplemented with selenomethionine

Selenium (Se) as a co-factor of antioxidant enzymes is metabolically essential for animals. Its presence in muscle can improve the oxidative stability of meat and is a desirable nutrient for consumers. A novel approach to Se supplementation for meat-producing livestock was demonstrated in a 95-day study of young lambs. DL-selenomethionine (SeMet) was administered by subcutaneous injection at day 0 (3–4 weeks of age) and again at day 54. A Control group (n = 9) received carrier only, whilst Medium and High groups (n = 10) received graded levels of Se. Physicochemical attributes of meat quality and sensory characteristics were measured at 1, 3, 14 and 42 days of ageing (vacuum packaged at −1.5 °C), followed by instrumental colour measurements after 7 days of simulated retail display. There were no significant interactions between SeMet treatment and ageing. Muscle pH, drip and cooking losses, initial display colour and sensory evaluations by trained and consumer panels were unaffected by treatment. Smaller changes in colour during display were observed for the Medium group compared to Control (P < 0.05). The shorter range of ageing times improved meat tenderness however extended ageing decreased colour stability. SeMet markedly increased Se concentrations in muscle, blood, kidney and liver (P < 0.05), resulting in Se enriched meat without appreciable changes in meat quality.

Preparation and properties of compositionally tunable Cu3Sb(Sx,Se1-x)4 thin films

In the paper, Cu3Sb(Sx,Se1-x)4 thin films were prepared by spin-coating method involving deposition of copper antimony sulfide precursor and then selenization of precursor in double-temperature zone space. The influence of selenium source temperature on properties of Cu3Sb(Sx,Se1-x)4 thin films was investigated. The phase structure, elemental composition, microstructure, optical and electrical properties were analyzed using appropriate characterization techniques. The results demonstrated Cu3Sb(Sx,Se1-x)4 thin films after selenization treatment had better crystallinity but Sb2Se3 impurity phase. The EDS analysis revealed that the Se concentration in the thin films increased with selenium source temperature. Morphological study indicated that the large grain appeared on the surface of thin films at higher selenium source temperature. The band gap of thin films linearly decreased with the increase of Se concentration. The as-prepared Cu3Sb(Sx,Se1-x)4 thin film showed p-type electrical behavior and an obvious photoconductivity.

Selenium-enriched Saccharomyces cerevisiae improves the meat quality of broiler chickens via activation of the glutathione and thioredoxin systems

The aim of this study was to investigate the effects of selenium (Se)-enriched Saccharomyces cerevisiae (SSC) on meat quality and to elucidate the underlying mechanisms in broilers. A total of 200 one-day-old Arbor Acres broiler chickens were randomly allocated to one of four treatments with 5 replications of 10 chickens each. Group 1 served as a control and was fed a basal diet without Se supplementation, while groups 2, 3, and 4 were fed the basal diet supplemented with S. cerevisiae (SC), sodium selenite (SS), and SSC, respectively. Breast muscle samples were collected to evaluate meat quality, selenium concentration, oxidative stability, and the mRNA levels of antioxidant enzyme genes on day 42. As compared with groups 1 and 2, SS and SSC supplementation increased Se concentration, glutathione peroxidase (GPx) and thioredoxin reductase (TR) activities, total antioxidant capacity, and the mRNA levels of GPx-1, GPx-4, TR-1, and TR-3 (P < 0.05) and decreased drip loss and malondialdehyde (MDA) content (P < 0.05). As compared with group 3, SSC supplementation increased pH, lightness, yellowness, Se concentration, GPx and superoxide dismutase activities, and the mRNA levels of GPx-1 and GPx-4 (P < 0.05) but decreased drip loss and MDA content (P < 0.05). Thus, SSC improved meat quality and oxidative stability by activating the glutathione and thioredoxin systems, which should be attributed to the combined roles of Se and SC.

Reduction of Cd accumulation in Se-biofortified rice by using fermented manure and fly ash.

Large areas of soils in China are contaminated with Cd and are deficient in Se. Therefore, here, we aimed to reduce Cd accumulation while increasing Se content in rice grain, and to elucidate the mechanisms associated. A greenhouse pot experiment was conducted to determine grain concentrations of Se and Cd upon foliar spraying of Se combined with the application of horse manure and/or fly ash to different contaminated soils containing Cd 0.51 (T1), 1.46 (T2), and 4.59mg Cd kg-1 (T3). The amount of Fe, Si, and Cd in root iron plaque, and concentrations of Cd and Si in rice tissues were also determined. Foliar spray of Se increased Se concentration in brown rice from approximately 0.04 to 0.15mgkg-1. Fly ash significantly reduced Cd concentration in brown rice from 0.07 to 0.05, 0.15 to 0.09, and 1.00 to 0.55mgkg-1 at the T1, T2, and T3 treatment levels, respectively, and soil Cd bioavailability (by at least 33.3%), while it increased Si content in rice roots and shoots by at least 34%. The increase of Si concentration in rice tissues inhibited Cd translocation to brown rice by at least 17%. Horse manure increased the formation of root Fe plaque by approximately 2.3-fold, which resulted in the significant reduction of Cd accumulation in brown rice, shoots, and roots by 36-56%. Thus, foliar spray of Se in combination with the application of fly ash and horse manure proved an effective method to produce Cd-low and Se-rich rice.

Selenium accumulation and growth of perennial ryegrass (Lolium perenne L.) as affected by pig manure composting

At trace concentrations, selenium (Se) has been shown to exert positive effects on plant growth, but Se essentiality to higher plants remains in doubt. Plants can absorb Se from the soil in inorganic or organic forms, but the cycling and bioavailability of organic Se in the manure-soil-plant system remain to be fully understood. This study investigated the effects of pig manure composting on the growth and Se accumulation in Lolium perenne L. (cv. Riikka) at different growth stages. A pot experiment with silica sand amended with Se-enriched mineral fertilizer (NPK-Se), dried, ground pig manure (PM) and pig manure compost (PMC) at 200 mg N kg-1 soil was carried out under controlled greenhouse conditions. Addition of NPK-Se, PM and PMC significantly (p ≤ 0.05) increased dry matter content in the stems and roots, on average, by 28 and 19% respectively. Inorganic (NPK-Se) and organic (PM and PMC) treatments slightly increased net photosynthesis, stomatal conductance, transpiration and leaf area in plants. Inorganic Se (NPK-Se) markedly increased Se content in the shoots, on average, by 35% at all growth stages. Even though Se concentration in the roots was 3-fold higher in pig manure (PM and PMC) fertilized-plants, translocation to the shoots was reduced. Interestingly, Se concentration in the shoots was higher in PMC-plants compared to PM-plants at all growth stages. However, the effect of composting on Se concentration was not significant. Overall, the results indicate that composting improves the fertilizer value of pig manure with possible stimulatory effects on organic-Se mineralization.

Bulk Superconductivity Induced by Se Substitution in Self-Doped BiCh2-Based Compound CeOBiS2−xSex

We report the Se substitution effects on the crystal structure, superconducting properties, and valence states of self-doped BiCh2-based compound CeOBiS2-xSex. Polycrystalline CeOBiS2-xSex samples with x = 0-1.0 were synthesized. For x = 0.4 and 0.6, bulk superconducting transitions with a large shielding volume fraction were observed in magnetic susceptibility measurements; the highest transition temperature (Tc) was 3.0 K for x = 0.6. A superconductivity phase diagram of CeOBiS2-xSex was established based on Tc estimated from the electrical resistivity and magnetization measurements. The emergence of superconductivity in CeOBiS2-xSex was explained with two essential parameters of in-plane chemical pressure and carrier concentration, which systematically changed with increasing Se concentration.

The role of O2 in CdSeTe thin film deposition and CdSeTe/CdTe solar cell performance

By integrating CdSeTe alloy into CdTe based thin-film solar cells, high efficiency above 19% has been obtained. However, the role of O2 during the CdSeTe deposition has not been studied since the current reported CdSeTe deposition process by close space sublimation (CSS) is free of oxygen. We found the oxygen performed an important role in this process. Here, we prepared CdSeTe films under O2/N2 ambient and apply them as absorb-layer together with CdTe. The effects of O2 on the CdSeTe deposition, material performance, and devices have been studied. Oxygen in the ambient can increase Se content in the CdSeTe alloy for the as-deposited films. A two-step reaction process of “oxidation - sublimation” is proposed to explain the role of oxygen. The oxygen facilitates the amount of Se content into the vapor then in the film. With the oxygen appearance, the composition of as-deposited CdSeTe films and the source can be controlled relative stable. This technique makes the process of depositing CdSeTe thin film by CSS for long time operation feasible. The short circuit current density (Jsc) and fill factor (FF) of the cells are promoted with the introduce of oxygen. A process of high efficiency (Eff.) (≥19%) CdSeTe/CdTe cells with oxygen in the CSS deposition is developed, which is repeatable and also compatible with both the existing manufacturing and laboratory CdTe process and equipment.

Enhanced thermoelectric properties of hydrothermally synthesized n-type Se&Lu-codoped Bi2Te3

N-type Se&Lu-codoped Bi2Te3 nanopowders were prepared by hydrothermal method and sintered by spark plasma sintering technology to form dense samples. By further doping Se element into Lu-doped Bi2Te3 samples, the thickness of the nanosheets has the tendency to become thinner. The electrical conductivity of Lu0.1Bi1.9Te3−xSex material is reduced with the increasing Se content due to the reduced carrier concentration, while the Seeback coefficient values are enhanced. The lattice thermal conductivity of the Lu0.1Bi1.9Te3−xSex is greatly reduced due to the introduced point defects and atomic mass fluctuation. Finally, the Lu0.1Bi1.9Te2.7Se0.3 sample obtained a maximum ZT value of 0.85 at 420 K. This study provides a low-cost and simple low-temperature method to mass production of Se&Lu-codoped Bi2Te3 with high thermoelectric performance for practical applications.

Effect of dietary selenium from selenium-enriched kale sprout, selenomethionine, and sodium selenite on performance and selenium concentrations in the tissues of growing quails

ObjectiveThis study aimed to determine the effect of dietary selenium (Se) from Se-enriched kale sprout (SeKS), selenomethionine (SeMet), and sodium selenite (SS) on performance, carcass characteristics and Se concentrations in the tissues, and to study the relationship between Se concentrations in muscle and feather in growing quails.MethodsThe 320 quails (7 d of age) were divided into four treatments, according to a completely randomized design. The treatments were T1: control diet; T2, T3, and T4: control diets plus 0.2 mg Se/kg from SS, SeMet, and SeKS, respectively. The performance, carcass characteristics, and Se concentrations in the tissues of quails were determined.ResultsThe results indicated no effect (p>0.05) of Se supplementation on performance, carcass characteristics and glutathione peroxidase (GSH-Px) activity in breast muscle of quails. Supplemental Se from SS, SeMet, and SeKS increased greater (p<0.05) Se concentrations in breast muscle, liver, kidney, heart, and feather, compared to those of quails fed the control diet. Quails fed Se from SeMet had greater (p<0.05) Se concentrations in the tissues than quails fed Se from SeKS and SS. In addition, Se concentrations in breast muscle and feather of quails at 21 and 42-d-old were highly correlated (R2 0.714 to 0.756) (p<0.05).ConclusionPerformance, carcass characteristics and GSH-Px activity in breast muscle of quails were not affected (p>0.05) by dietary Se supplementation. The Se from SeMet was more effective in increasing Se concentrations in the tissues of quails than Se from SeKS and SS. Feather Se concentrations of 21 and 42-d-old quails can be used for assessment of Se bioavailability of Se sources.

Optical and Thermoelectric Properties of Surface-Oxidation Sensitive Layered Zirconium Dichalcogenides ZrS2−xSex (x = 0, 1, 2) Crystals Grown by Chemical Vapor Transport

In this work, structure, optical, and thermoelectric properties of layered ZrS2−xSex single crystals with selenium composition of x = 0, 1, and 2 were examined. Single crystals of zirconium dichalcogenides layer compounds were grown by chemical vapor transport method using I2 as the transport agent. X-ray diffraction (XRD) and high-resolution transmission electron microscope (HRTEM) results indicated that ZrS2−xSex (x = 0, 1, and 2) were crystalized in hexagonal CdI2 structure with one-layer trigonal (1T) stacking type. X-ray photoelectron and energy dispersive X-ray measurements revealed oxidation sensitive behavior of the chalcogenides series. Transmittance and optical absorption showed an indirect optical gap of about 1.78 eV, 1.32 eV, and 1.12 eV for the ZrS2−xSex with x = 0, 1, and 2, respectively. From the result of thermoelectric experiment, ZrSe2 owns the highest figure-of merit (ZT) of ~0.085 among the surface-oxidized ZrS2−xSex series layer crystals at 300 K. The ZT values of the ZrS2−xSex (x = 0, 1, and 2) series also reveal increase with the increase of Se content owing to the increase of carrier concentration and mobility in the highly Se-incorporated zirconium dichalcogenides with surface states.

Selenium biofortified alfalfa hay fed in low quantities improves selenium status and glutathione peroxidase activity in transition dairy cows and their calves.

The hypothesis of the study was that feeding a relatively low amount of Se biofortified alfalfa hay during the dry period and early lactation would improve selenium status and glutathione peroxidase activity in dairy cows and their calves. Ten Jersey and 8 Holstein primiparous dairy cows were supplemented with Se biofortified (TRT; n = 9) or non-biofortified (CTR; n = 9) alfalfa hay at a rate of 1 kg/100 kg of BW mixed with the TMR from 40 d prior parturition to 2 weeks post-partum. Se concentration in whole blood, liver, milk, and colostrum, the transfer of Se to calves, and the glutathione peroxidase (GPx) activity were assessed. TRT had 2-fold larger (P < 0.05) Se in blood v. CTR that resulted in larger Se in liver and colostrum but not milk and larger GPx activity in plasma and erythrocytes but not in milk. Compared to CTR, calves from TRT had larger Se in blood but only a numerical (P = 0.09) larger GPx activity in plasma. A positive correlation was detected between Se in the blood and GPx activity in erythrocytes and plasma in cows. Our results demonstrated that feeding pregnant primiparous dairy cows with a relatively low amount of Se-biofortified alfalfa hay is an effective way to increase Se in the blood and liver, leading to greater antioxidant activity via GPx. The same treatment was effective in improving Se concentration in calves but had a modest effect on their GPx activity. Feeding Se biofortified hay increased Se concentration in colostrum but not in milk.

Patterns of Trace Element Accumulation in Waterfowl Restricted to Impoundments Holding Coal Combustion Waste.

Waterfowl are often exposed to and readily accumulate anthropogenic contaminants when foraging in polluted environments. Settling impoundments containing coal combustion waste (CCW) enriched in trace elements such as arsenic (As), selenium (Se), and mercury (Hg) are often used by free-ranging migratory and resident waterfowl and represent potential sources for contaminant uptake. To assess accumulation of CCW contaminants, we experimentally restricted waterfowl to a CCW-contaminated impoundment and quantified trace element burdens in blood, muscle, and liver tissues over known periods of exposure (between 3 and 92 d). From these data we developed models 1) to predict elemental bioaccumulation with increased exposure time, and 2) to predict muscle/liver burdens based on concentrations in blood as a nondestructive sampling method. Although Hg and As did not bioaccumulate in our waterfowl, we observed an increase in Se concentrations in muscle, liver, and blood tissues over the duration of our experiment. Furthermore, we found that blood may be used as an effective nondestructive sampling alternative to predict muscle and liver tissue concentrations in birds contaminated with Se and As through dietary exposure. These data provide unique insights into accumulation rates of contaminants for waterfowl utilizing habitats contaminated with CCW and demonstrate the efficacy of nonlethal sampling of waterfowl to quantify contaminant exposure. Environ Toxicol Chem 2020;39:1052-1059. © 2020 SETAC.

Superconductivity in Se-doped La2O2Bi2Pb2S6-xSexwith a Bi2Pb2Ch4-type thick conducting layer

La2O2Bi2Pb2S6 is a layered Bi-based oxychalcogenide with a thick four-layer–type conducting layer. Although La2O2Bi2Pb2S6 is a structural analogue of La2O2Bi3AgS6, which is a superconductor, insulating behavior has been observed in La2O2Bi2Pb2S6 at low temperatures, and no superconductivity has been reported. Herein, we demonstrate superconductivity in La2O2Bi2Pb2S6-xSex via partial substitution of Se in the S sites. Owing to the Se doping, the normal state electrical resistivity of La2O2Bi2Pb2S6-xSex at low temperatures was dramatically suppressed, and superconductivity was observed at a transition temperature () of 1.2 K for . increased with increasing Se concentration: for . By applying high pressure for , bulk superconductivity was confirmed and the increased up to 3.6 K at 0.89 GPa.

Serum Selenium, Iron, Zinc, and Copper Concentrations in Renal Transplant Recipients Treated with Mycophenolate Mofetil

There are data available in the literature on bioelement concentrations in the serum of various groups of patients; however, very little is known about the serum concentration of selenium (Se), iron (Fe), zinc (Zn), and copper (Cu) in renal transplant patients treated with immunosuppressive drugs, including mycophenolate mofetil (MMF). Monitoring of serum bioelement concentrations in renal transplant recipients is of profound importance, as the proper bioelement levels seem to prolong the normal function of the transplanted organ. Thus, the aim of this current study was to examine and carry out comparative analysis involving serum concentrations of Se, Fe, Cu, and Zn of renal transplant recipients treated with MMF and without MMF. The material consisted of blood samples from 115 patients of the Department of Nephrology, Transplantology, and Internal Medicine of Independent Public Clinical Hospital No. 2, Pomeranian Medical University, in the city of Szczecin in the northwestern Poland. Serum Se, Fe, Cu, and Zn levels were quantified by inductively coupled mass spectroscopy (ICP-MS). Taking into account all patients, MMF increases Cu level. Cu and Fe concentrations were significantly higher in women treated with MMF; in group of younger patients treated with MMF, Se level was significantly lower comparing with those whose regimen did not include MMF. Additionally, MMF in combination with prednisone increased Se concentration in blood of transplant recipients. Our study highlights that trace elements should be monitored to allow for an early detection of trace elements deficits, which can easily be corrected for by an adjusted diet or supplemental intake.

In vitro selenium bioaccessibility combined with in vivo bioavailability and bioactivity in Se-enriched microalga (Chlorella sorokiniana) to be used as functional food

Abstract Speciation of seleno-metabolites and selenoproteins in Se-enriched Chlorella sorokiniana microalgae, in vitro and in vivo extracts has been performed by HPLC-ICP-MS. Selenium bioaccesibility in Se-enriched Chlorela sorokiniana evaluated by in vitro gastrointestinal digestion of the selenized microalga was 81% (79% as SeMet). Mice supplemeted with Se-enriched C. sorokiniana presented increased Se concentration in kidney, reflecting a potencial mechanism of excretion by urine. In addition, selenium bioavailavility, which was in the range of 3–15% depending on the diet was 1.13-fold higher in mice fed with Se-enriched microalgae against the basal diet, but decreased with higher amounts of selenium. Regarding bioactivity (∑Se as selenoproteins in serum/total Se in serum = 76–85% depending on the diet), selenium and selenoproteins (SeP) increased in serum from animals fed high supplemental Se levels. These results showed that Se-enriched algae can be considered as an alternative selenized food for humans, due to their high Se bioavailability.

Characterization of selenium oxide nanofiller effect on the spectroscopic and thermal properties of Cs/PAM nanocomposites

Nanocomposite samples of chitosan (Cs)/polyacrylamide (PAM) blend incorporated with different concentrations of selenium oxide (SeO2) nanoparticles were fabricated and investigated. The results of Cs/PAM-SeO2 nanocomposites show an exchange in the physical and thermal properties. The X-ray diffraction shows the semicrystalline nature for pure Cs/PAM blend which decreased with the increase of Se contents, causing a decrease of the degree of crystallinity inside Cs/PAM films. The absence of Se peaks for doped films indicates that Se was finely dispersed in polymeric matrices. The FT-IR spectra display a change in the intensities of some bands compared with the spectrum of the virgin Cs/PAM, which indicates that an interaction and complexation between Cs/PAM and selenium nanoparticles took place. The UV–vis measurements revealed that the values of the direct and forbidden direct optical energy gap (Egd and Egf) decreased after the addition of Se nanoparticles. The TG, DTG and DSC analysis were used to investigate the thermal properties of the nanocomposites. The TG thermograms show two regions at ≈ 100 °C varied from 2.8 to 4.6 % weight loss due to the evaporation of water and moisture absorbed, and the other from 244 to 433 °C related to ≈9.5% to ≈55.2 % weight loss. The shifts of TG curves result in a higher temperature indicating that, with the addition of Se, the thermal stability increases with increasing Se content. The values of the change of activation entropy (ΔS*), change of activation enthalpy (ΔH*), and Gibbs free activation function (ΔG*) were calculated. The small increase of both ΔH* and ΔG* reveals that the total energy was increased with respect to the reagents and compound formation activated.

Effect of Composition on the Optical and Electrical Conductivity of CuIn(SexS1−x)2

Optical and electrical conductivity of chalcopyrite CuIn(SexS1−x)2 (0 ≤ x ≤ 1) amorphous thin films are investigated. A transmission has been measured in a wavelength range (200 ≤ λ ≤ 2500 nm). The calculated optical energy band gap (Eg) and Urbach tail (band tail width) Eu decrease with increasing Se content. Refractive index (n) is estimated according to the Wemple–DiDomenico single oscillator model. Oscillator energy (E°), dispersion energy (Ed), and the ratio of free carrier concentration to electron effective mass (N/m*) are calculated from optical data for all thin films. Also, the high frequency dielectric constant at an infinite wavelength (e∞), lattice high frequency dielectric constant (eL) and static refractive index (n°) are determined. Electrical conductivity (σ) is obtained at room temperature.

Alternative selenium supplement for sheep

This study investigated Se-dependent parameters in ewes after supplementation with an experimental Se product (P-Se) in comparison to sodium selenite. Six Dorset ewes averaging 93.0 (SE = 2.5) kg initial body weight were used in a replicated 3 × 3 Latin square design experiment balanced for residual effects. The study began with a 2-wk background, low-Se period and had 3 experimental periods of 3 weeks each, with 2-wk washout periods between them. The treatments studied were: (1) unsupplemented control (basal diet containing 0.065 mg Se/kg dry matter, DM); (2) basal diet supplemented with Na-selenite providing 0.25 mg Se/kg DM; and (3) basal diet supplemented with P-Se (containing 29 % Na-selenite and 71 % amorphous elemental Se) providing 0.27 mg Se/kg DM (P-Se). Blood samples (taken from the jugular vein) and spot urine and fecal samples were collected the day before the start of each experimental period, on the last day of each washout period, and once weekly during the experimental periods for analysis of Se concentration and glutathione peroxidase (GPx) activity (blood plasma only). Ewes supplemented with P-Se and Na-selenite had increased (P < 0.001) plasma Se concentration compared with ewes fed the control diet. Absolute concentration of Se in plasma was greater (P < 0.001) for ewes fed Na-selenite (80.9 μg/L) than for ewes fed P-Se (72.3 μg/L). Absolute plasma GPx activity was greater (P < 0.001) for ewes fed Na-selenite and P-Se compared with the control, but was not different between the Se treatments. Concentration of Se in fecal matter was greater (P < 0.001) for both Se sources than the control and fecal Se concentration was higher (P < 0.001) for P-Se compared with Na-selenite. Absolute Se concentration in urine was greater (P ≤ 0.003) for Na-selenite than the control and P-Se. Selenium supplementation of ewe diet increased Se concentration and GPx activity in blood plasma, regardless of Se source. Although P-Se had slightly inferior absorption, compared with Na-selenite, our data indicate that it can potentially be an effective source of dietary Se for mature ewes, but further studies are needed to confirm these results in other farm animal species and physiological stages.

Effect of Anionic Substitution of S by Se in CZTSSe Films Prepared from Electron Beam Evaporation

Abstract Cu2ZnSnSxSe4-x (CZTSSe) is a prominent candidate as a photon absorber layer in solar cell owing to its earth abundant constituents and high absorption coefficient with tunable bandgap. In this study, the effect of metallic stacking order and anionic substitution of S by Se on the properties of CZTSSe is investigated by varying the S/Se ratio. CZT metallic precursor films with stacking sequences SLG/Sn/Zn/Cu and SLG/Cu/Sn/Zn/Cu are fabricated on soda lime glass substrate by using electron beam evaporation of elemental metallic precursors. In order to obtain CZTSSe films with various S/Se ratio, the films are annealed in the presence of elemental S and Se environment with various ratio of elemental S and Se powder at 550 °C for 1 hour at a ramping rate of 10 °C/min with N2 as a carrier gas. The effect of variation of S/Se powder on crystallinity, morphology and composition of the films are confirmed through X-Ray diffraction, Raman spectroscopy, FEGSEM and EDS analysis. The optical bandgap of the films is estimated to decrease with increasing Se content in the films. The Se incorporation is noticed the highest in case of SLG/Sn/Zn/Cu stack and its bandgap is found to be decreasing from 1.53 to 1.2 eV with increasing Se content.

Association of Maternal Prenatal Selenium Concentration and Preterm Birth: A Multi-Country Meta-Analysis

Background: Selenium (Se), an essential trace mineral, has been implicated in preterm birth (PTB). We aimed to determine the association of maternal Se concentrations during pregnancy with PTB risk and gestational duration in a large number of samples collected from diverse populations. Methods: Gestational duration data and maternal plasma or serum samples of 9946 singleton live births were obtained from 17 geographically diverse study cohorts. Maternal Se concentrations were determined by Inductively coupled plasma mass spectrometry (ICP-MS) analysis. The associations between maternal Se with PTB and gestational duration were analyzed using linear and logistic regressions. The results were then combined using fixed and random effect meta-analysis. Findings: In all study samples, the Se concentrations followed a normal distribution with a mean of 93.8 ng/ml (range: 26.1 to 228.7 ng/ml) but varied substantially across different sites. The fixed-effect meta-analysis across the 17 cohorts showed that Se was significantly associated with PTB (p = 0.04) and gestational duration (p = 2.9e-6) with effect size estimates of an OR= 1.04 (95% CI: 1.0 to 1.07) for PTB per 10 ng/ml decrease in Se concentration and 0.44 days (95% CI: 0.26 – 0.62) longer gestation per 10 ng/ml increase in Se concentration. However, there was a substantial heterogeneity among study cohorts. The largest effect sizes were observed in UK (Liverpool) cohort, while the most statistically significant associations were observed in samples from Malawi. After excluding these two cohorts, the fixed effect meta-analysis was no longer significant, and the random-effect meta-analysis of all data sets also did not achieve statistical significance. Interpretation: While our study observed statistically significant associations between maternal Se concentration and PTB at some sites, this did not generalize across the entire cohort. Whether population-specific factors explain the heterogeneity of our findings warrants further investigation. Targeted Se supplementation could play a role in reducing PTB in some settings, however further evidence is needed to understand the biologic pathways, clinical efficacy and safety, before changes to antenatal nutritional recommendations are considered. Funding Statement: Payment for access to data and article-processing charges for this publication was covered by The Bill & Melinda Gates Foundation (Grant no: OPP1175128, OPP1152451). The NEST study acknowledges the support from National Institute of Environmental Health Sciences, the US Environmental Protection Agency, the National Institute of Diabetes and Digestive and Kidney Diseases, and the Duke Cancer Institute. Th CPPOP study acknowledge support from the UCSF California Preterm Birth Initiative. The iLiNS-DYAD-M trial acknowledge the support by a grant to the University of California, Davis from The Bill & Melinda Gates Foundation [OPP49817] and a grant to the University of California, Davis from the Office of Health, Infectious Diseases, and Nutrition, Bureau for Global Health, U.S. Agency for International Development (USAID) through the Food and Nutrition Technical Assistance III Project (FANTA). MDIG, AMANHI, GAPPS and INTERBIO cohorts acknowledge the support by The Bill & Melinda Gates Foundation. Declaration of Interests: The authors declare no conflicts of interest regarding the content of this paper. Ethics Approval Statement: Our study protocol was approved by the Institute Review Board (IRB) of the CCHMC and by the corresponding Ethics Committees of each participating institution.