Se Compounds Research Articles

First-principles simulations of magnetic properties of Co- and Ni-doped ZnSe

We purposed to analyze the theoretical ab initio study of ferromagnetism and to estimate Curie temperature of Co2+ and Ni2+ 3d transition metal (TM) ions doped Zn1-x TM x Se compounds for 12.5 % and 6.25 % concentrations of impurity TM(Co, Ni) atoms. The calculations are carried out using the norm-conserving Fritz-Haber-Institute ionic pseudopotentials based on density functional theory within the local spin density approximation and Hubbard U (U(Znd)=4.5 eV; U(Sep)=3.8 eV) corrections. The analysis of the total and partial electron density of states shows the half-metallic ferromagnetic behavior with a half-metallic bandgap. The theoretically obtained total magnetic moments of TM(Co, Ni) doped Zn1-x TM x Se systems are equal to 3 μB and 4 μB, correspondingly.

Selenium speciation studies in cancer patients to evaluate the responses of biomarkers of selenium status to different selenium compounds

This work presents the first systematic comparison of selenium (Se) speciation in plasma from cancer patients treated orally with three Se compounds (sodium selenite, SS; L-selenomethionine, SeMet; or Se-methylselenocysteine, MSC) at 400 µg/day for 28 days. The primary goal was to investigate how these chemical forms of Se affect the plasma Se distribution, aiming to identify the most effective Se compound for optimal selenoprotein expression. This was achieved using methodology based on HPLC-ICP-MS after sample preparation/fractionation approaches. Measurements of total Se in plasma samples collected before and after 4 weeks of treatment showed that median total Se levels increased significantly from 89.6 to 126.4 µg kg−1 Se (p < 0.001), particularly when SeMet was administered (190.4 µg kg−1 Se). Speciation studies showed that the most critical differences between treated and baseline samples were seen for selenoprotein P (SELENOP) and selenoalbumin after administration with MSC (p = 5.8 × 10−4) and SeMet (p = 6.8 × 10−5), respectively. Notably, selenosugar-1 was detected in all low-molecular-weight plasma fractions following treatment, particularly with MSC. Two different chromatographic approaches and spiking experiments demonstrated that about 45% of that increase in SELENOP levels (to ~ 8.8 mg L−1) with SeMet is likely due to the non-specific incorporation of SeMet into the SELENOP affinity fraction. To the authors’ knowledge, this has not been reported to date. Therefore, SELENOP is probably part of both the regulated (55%) and non-regulated (45%) Se pools after SeMet administration, whereas SS and MSC mainly contribute to the regulated one.Graphical abstract

Reactions of hypobromous acid with dimethyl selenide, dimethyl diselenide and other organic selenium compounds: kinetics and product formation.

Selenium (Se) is an essential micronutrient for many living organisms particularly due to its unique redox properties. We recently found that the sulfur (S) analog for dimethyl selenide (DMSe), i.e. dimethyl sulfide (DMS), reacts fast with the marine oxidant hypobromous acid (HOBr) which likely serves as a sink of marine DMS. Here we investigated the reactivity of HOBr with dimethyl selenide and dimethyl diselenide (DMDSe), which are the main volatile Se compounds biogenically produced in marine waters. In addition, the reactivity of HOBr with further organic Se compounds was tested, i.e., SeMet (as N-acetylated-SeMet), and selenocystine (SeCys2 as N-acetylated-SeCys2), as well as the phenyl-analogs of DMSe and DMDSe, respectively, diphenyl selenide (DPSe) and diphenyl diselenide (DPDSe). Apparent second-order rate constants at pH 8 for the reactions of HOBr with the studied Se compounds were (7.1 ± 0.7) × 107 M-1 s-1 for DMSe, (4.3 ± 0.4) × 107 M-1 s-1 for DMDSe, (2.8 ± 0.3) × 108 M-1 s-1 for SeMet, (3.8 ± 0.2) × 107 M-1 s-1 for SeCys2, (3.5 ± 0.1) × 107 M-1 s-1 for DPSe, and (8.0 ± 0.4) × 106 M-1 s-1 for DPDSe, indicating a very high reactivity of all selected Se compounds with HOBr. The reactivity between HOBr and DMSe is lower than for DMS and therefore this reaction is likely not relevant for marine DMSe abatement. However, the high reactivity of SeMet with HOBr suggests that SeMet may act as a relevant quencher of HOBr.

Formation of Quaternary Czt(S,Se) Compounds Using Hydrothermal Synthesis and Spin Coating Technique

Formation of Quaternary Czt(S,Se) Compounds Using Hydrothermal Synthesis and Spin Coating Technique

PREPARATION, CHARACTERIZATION, AND STUDY OF THE BIOLOGICAL ACTIVITY OF 5-CHLORO-8-QUINOLINOL DERIVATIVES AND ITS COORDINATION WITH THE NICKEL (II) AND DIPHOSPHINES

Nickel complexes are effective catalysts for cross-coupling reactions between alkyl Grignard reagents and alkenyl–S and alkenyl–Se compounds. In this study, various organic compounds were prepared. Ethylnyl 2-((5-chloro-8-quinolinol)oxy) acetate compound (designated as A1) was synthesized by adding potassium carbonate to quinoline and ethyl chloroacetate. The second compound 2-((5-chloro-8- quinolinol)oxy) acetohydrazide (A2) were obtained by reacting A1with hydrazide. Complex compound A3 were obtained by reacting equimolar amounts of compound A2 with the nickel salt solution, using ethanol as the solvent. Phosphinate complexes were prepared by reacting equal moles of the A3 with the various phosphines and using ethanol as a solvent. The synthesized compounds and complexes were characterized using various spectroscopic techniques, including (FT-IR) spectroscopy, (31P-{ 1H}- 13C-NMR) spectroscopy, and C.H.N. analysis. Additionally, their melting points, purity, molar conductivity, and magnetic susceptibility were determined. The impact of some prepared compounds and complexes on the growth of two antibiotic-resistant bacterial strains, namely the Gram-negative Staphylococcus and the Gram-positive Escherichia coli, was studied. Amoxicillin was used as control antibiotics. Some of the synthesized compounds exhibited significant inhibitory activity against the tested bacterial strains. The A2 compound readily forms complexes, especially with nickel, manganese, and copper salts. The prepared compounds and complexes exhibited high stability and strength, maintaining their structure, color, and melting point even under varying laboratory temperatures between winter and summer

Selenoproteins in Health.

Selenium (Se) is a naturally occurring essential micronutrient that is required for human health. The existing form of Se includes inorganic and organic. In contrast to the inorganic Se, which has low bioavailability and high cytotoxicity, organic Se exhibits higher bioavailability, lower toxicity, and has a more diverse composition and structure. This review presents the nutritional benefits of Se by listing and linking selenoprotein (SeP) functions to evidence of health benefits. The research status of SeP from foods in recent years is introduced systematically, particularly the sources, biochemical transformation and speciation, and the bioactivities. These aspects are elaborated with references for further research and utilization of organic Se compounds in the field of health.

Progressive carrier density optimization contributes to enhanced thermoelectric performance in Bi(Te, Se) compound

Layered BiTe and BiSe compounds present promising n-type thermoelectric performance, but the intrinsic high carrier density limits ZT value near room temperature. In this work, thermoelectric performance in Bi(Te, Se) compound is significantly improved by progressively optimizing its carrier density. The room-temperature carrier density is reduced from ∼5.5 × 1020 cm−3 in Bi0.99Te to ∼2.21 × 1020 cm−3 in Bi0.92Sn0.07Te0.4Se0.6-2%Cu, which can lead to obvious enhancement of Seebeck coefficient and power factor, and thus the room-temperature power factor increases from ∼4.17 μW cm−1 K−2 in Bi0.99Te to ∼9.78 μW cm−1 K−2 in Bi0.92Sn0.07Te0.4Se0.6-2%Cu. Moreover, the largely suppressed total thermal conductivity in Bi0.92Sn0.07Te0.4Se0.6-2%Cu also benefit from lowered carrier density because of reduced electronic thermal conductivity, as well as intensified phonon scattering caused by imported point defects. Finally, a room-temperature ZT of ∼0.29 and a peak value of ∼0.41 at 373 K in Bi0.92Sn0.07Te0.4Se0.6-2%Cu are achieved successfully, which are ∼6 and ∼3 times higher than that in Bi0.99Te, respectively.

In-depth analysis of ternary NaCuX (X = Se and Te) chalcogenides: Bridging structural elastic, electronic, and optical properties

This study employs density functional theory (DFT) using the full potential linearized augmented plane wave plus local orbital (FP-LAPW+1o) approach to investigate the structural, elastic, electronic, and optical properties of NaCuX (X = Se and Te) compounds. Additionally, the modified Becke-Johanson (TB-mBJ) potential is applied to ensure accurate band gap results. Both compounds exhibit semiconducting behavior with a direct band gap at the Γ point. The computed elastic constants confirm mechanical stability for NaCuSe and NaCuTe, as evidenced by their respective bulk modulus, Young modulus, shear modulus, Poisson's ratio, B/G ratio, and elastic anisotropy. The materials display ductile characteristics, indicated by their B/G ratio and Poisson's ratio. The Debye temperature (θD) reveals that NaCuSe possesses the highest thermal conductivity. A decrease in θD is observed from NaCuSe to NaCuTe due to declining elastic constants. Additionally, anisotropy in acoustic velocities is assessed and discussed. The study's equilibrium structural properties align well with experimental data. Optical properties, including frequency-dependent dielectric function, refractive index, extinction coefficient, absorption coefficient, reflectivity, and energy loss function, are calculated and comprehensively analyzed.

Polyphenol‐mediated construction of highly stable and bioactive selenium nanoparticles

AbstractSelenium (Se), a well‐known essential element in human health, plays a vital role in regulating metabolism owing to its antioxidative nature. However, organic Se compounds are toxic and cannot be used for biomedical applications. Selenium nanoparticles (SeNPs) exhibit low biological toxicity and high bioavailability; however, they are prone to aggregation and are extremely unstable, thereby diminishing their bioactivity and bioavailability. To overcome these limitations, ultra‐small, highly stable, and bioactive SeNPs were synthesised based on an in‐situ hybridisation strategy by using polyphenol‐grafted‐chitosan (GA‐CS) to control and restrict crystal growth of Se nanoparticles. The resultant GA‐CS@nSe exhibited an average particle size of ∼30 nm and was highly stable in aqueous solutions. In addition, GA‐CS@nSe displayed improved biocompatibility and enhanced antioxidative activity. Taken together, the authors provide a basis for polyphenol‐mediated construction of Se‐based particles with increased bioactivity.

Selenium foliar application contributes to decrease ratio of water-soluble fluoride and improve physio-biochemical components in tea leaves

The tea plant accumulates elevated levels of fluoride (F) from environmental sources. Drinking tea containing high F levels poses a potential threat to human health. Selenium (Se) was applied by foliar spray to investigate its effects on F accumulation and physiology in tea plant. Foliar application of different forms of Se, i.e., Na2SeO3, Kappa-selenocarrageenan, Selenomethionine and Nanoselenium, reduced F content in tea leaves by 10.17 %−44.28 %, 16.12 %−35.41 %, 22.19 %−45.99 % and 22.24 %−43.82 %, respectively. Foliar spraying Se could increase F accumulation in pectin through increasing pectin content and pectin demethylesterification to bind more F in the cell wall, which decreased the proportion of water-soluble fluoride in tea leaves. Application of Se significantly decreased the contents of chromium (39.6 %−72.0 %), cadmium (48.3 %−84.4 %), lead (2.2 %−44.4 %) and copper (14.1 %−44.6 %) in tea leaves. Foliar spraying various forms of Se dramatically increased the Se content and was efficiently transformed into organic Se accounting for more than 80 % in tea leaves. All Se compounds increased peroxidase activity by 3.3 %−35.5 % and catalase activity by 2.6 %−99.4 %, reduced malondialdehyde content by 5.6 %−37.1 %, and increased the contents of chlorophyll by 0.65 %−31.8 %, carotenoids by 0.24 %−27.1 %, total catechins by 1.6 %−21.0 %, EGCG by 4.4 %−17.6 % and caffeine by 9.1 %−28.6 %. These results indicated that Se application could be served as a potential efficient and safe strategy diminishing the concentration of F in tea leaves.

Evaluation of the Neuroprotective Effect of Organic Selenium Compounds: An in Vitro Model of Alzheimer's Disease.

Selenium (Se) is an essential trace element for human health and plays an important role in the development and maintenance of central nervous system functions. Se deficiency has been associated with cognitive decline and increased oxidative stress. The increase in oxidative stress is one of the hypotheses for the emergence and worsening of neurodegenerative diseases, such as Alzheimer's disease (AD). To investigate the neuroprotective effects of organic Se compounds in human neuroblastoma cells (SH-SY5Y) differentiated into cholinergic neurons-like. The SH-SY5Y cells were differentiated into cholinergic neuron-like with retinoic acid (RA) and brain-derived neurotrophic factor (BDNF). AD was mimicked exposing the cells to okadaic acid (OA) and beta-amyloid protein (Aβ). The neuroprotective effect of organic Se compounds, selenomethionine (SeMet) and Ebselen, was evaluated through cell viability tests, acetylcholinesterase and antioxidant enzyme activities, and detection of reactive oxygen species (ROS). None of the SeMet concentrations tested protected against the toxic effect of OA + Aβ. On the other hand, previous exposure to 0.1 and 1 µM Ebselen protected cells from the toxic effect of OA + Aβ. Cell differentiation induced by RA and BDNF exposure was effective, showing characteristics of neuronal cells, and pointing to a promising model of AD. Ebselen showed a protective effect, but more studies are needed to identify the mechanism of action.

ELECTRODEPOSITION SILVER(I) SELENIDE FROM AQUEUOS THIOCYANATE SOLUTIONS

Electrodeposition of silver(I) selenide possessing pronounced thermoelectric properties was carried out from aqueous solutions containing thiocyanate complexes of silver(I) and Se (IV) compounds at pH 4.7. Ag2Se is formed at cathode potentials more negative than –0.9 V (s.h.e.). The obtained coatings were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray phase analysis (XPA), and atomic force microscopy (AFM). The stoichiometry of the cathode deposit is close to Ag2Se. Diffraction studies have shown that an orthorhombic modification of silver(I) selenide is formed under electrodeposition conditions. Cathode deposits have a columnar nanostructure.

The Ozonolysis of Methylated Selenide Compounds in the Atmosphere: Isotopes, Kinetics, Products, and Mechanisms.

Selenium (Se) is an essential micronutrient with an important atmospheric component in its biogeochemical cycle. In this cycle, phytoplankton form volatile organic Se species, such as dimethyl selenide (CH3SeCH3) and dimethyl diselenide (CH3SeSeCH3), which are emitted into the atmosphere. To predict the atmospheric fate of these methylated Se compounds, we investigated their ozonolysis reaction. We used proton-transfer-reaction time-of-flight mass spectrometry to quantify atmospheric Se and its isotopes, and used this method in kinetic and product studies. The ozonolysis of CH3SeCH3 proceeded with a rate constant of (7.4 ± 2.2) × 10-17 cm3 molec-1 s-1 at 26 ± 1 °C with an activation energy of 50 ± 14 kJ mol-1 forming dimethyl selenoxide (CH3Se(O)CH3). Comparatively, CH3SeSeCH3 reacted with O3 at (2.6 ± 0.9) × 10-17 cm3 molec-1 s-1 at 27 ± 1 °C with an activation energy of 56 ± 5 kJ mol-1 forming methylselinic acid (CH3Se(O)OH). At 20 ppbv of O3, the atmospheric lifetimes of CH3SeCH3 and CH3SeSeCH3 are 7.6 and 22 h, respectively. The Se oxidation products were confirmed by synthesis and can serve as new atmospheric tracers of methylated Se compounds. Overall, we measured Se isotopes in real time and determined the rate constants, activation energies, and oxidation products. These mechanisms can now be used to determine the quantitative atmospheric fate of Se toward O3, and thus its distribution within a changing climate.

Exploring the Optoelectronic Potential of M2SnX3F2 (M = Sr, Ba; X = S, Se) Compounds Through First-Principles Analysis of Structural, Electronic, and Optical Properties

Exploring the Optoelectronic Potential of M2SnX3F2 (M = Sr, Ba; X = S, Se) Compounds Through First-Principles Analysis of Structural, Electronic, and Optical Properties

Systematic investigation of magneto-electronic, structural, thermoelectric and optical properties of Nd2MgX4 (X = S, Se) compounds

The structural, magnetic, optoelectronic, and thermoelectric (TE) characteristics of Nd2MgX4 (X = S, Se) are determined by utilizing the density functional theory (DFT) based full potential linearized augmented plane wave (FP-LAPW) method as employed in WEIN2k code. The exchange and correlation energies along with Coulomb interactions are brought into consideration by employing local density of approximation with Hubbard model (LDA+U). Tolerance (τ) factor and formation enthalpy were utilized to confirm the stability of both spinels. τ values are 0.70 and 0.68, and formation enthalpy values are (ΔHf) are -3.34 eV and -2.19 eV for Nd2MgX4 (X = S, Se), respectively. For Nd2MgX4 (X = S, Se) metallic behavior is found in spin up case while considerable bandgaps are found in spin down with half metallic bandgap (Eg) values of 1.82 and 1.26 eV (in spin down), correspondingly. The calculated magnetic moment for Nd2MgX4 (X = S, Se) are 12.0008 μB and 12.0003 μB, respectively. Furthermore, optical features including refractive index n(ω), dielectric constant 𝜀𝜀(𝜔𝜔), reflectivity R(ω), optical conductivity σ(ω), absorption coefficient α(ω) and extinction coefficient k(ω) are computed. The maximum calculated real part of dielectric constant 𝜀𝜀1(𝜔𝜔) values for Nd2MgX4 (X = S, Se) are 9.2 and 10.8, respectively. For Nd2MgX4 (X = S, Se), σ(ω) has maximum value of 7642.9 at 6.6 and 7592.5 (Ω cm)-1 at 5.99 eV, respectively. The various temperature dependent thermoelectric (TE) parameters along with figure of merit (ZT) are determined to get full insight into the TE behavior for both compounds by using BoltzTraP code. The computed ZT value for Nd2MgSe4 is 0.81 at 800 K while Nd2MgS4 has ZT value of 0.80 at 800 K. Results showed that both spinels have potential in spintronics and in cooling industries.

Effective spin-orbital coupling determined topological properties of Half-Heusler compounds XYZ (X = Li, Na, K; Y = Ag, Au; Z = S, Se, Te)

The topological properties of half Heusler compounds XYZ (X = Li, Na, K; YAg, Au; Z = S, Se, Te) are studied by the density functional theory and k ⋅ p method. The S-based compounds are topological insulators in both cubic and tetragonal structures, because of the negative spin-orbital coupling (SOC). While the Se and Te-based compounds are topological semimetals because of their positive SOC.

Toxic or beneficial? What is the role of food‐relevant selenium species selenoneine?

Toxic or beneficial? What is the role of food‐relevant selenium species selenoneine?

Sodium Selenate, Potassium Hydroxy-Selenide, Acetylselenide and Their Effect on Antioxidant Metabolism and Plant Nutrition and Yield in Sorghum Genotypes.

Agronomic biofortification with selenium (Se) effectively reduces hidden hunger and increases the nutritional intake of Se in people and animals. Because sorghum is a staple diet for millions of people and is used in animal feed, it becomes a crop with biofortification potential. Consequently, this study aimed to compare organoselenium compounds with selenate, which is effective in numerous crops, and to assess grain yield, the effect in the antioxidant system, and macronutrient/micronutrient contents of different sorghum genotypes treated with Se, via foliar spray. The trials used a 4 × 8 factorial design, with four Se sources (control-without Se supply, sodium selenate, potassium hydroxy-selenide, acetylselenide) and eight genotypes (BM737, BRS310, Enforcer, K200, Nugrain320, Nugrain420, Nugrain430, and SHS410). The Se rate used was 0.125 mg plant-1. All genotypes reacted effectively to foliar fertilization with Se through sodium selenate. In this experiment, potassium hydroxy-selenide and acetylselenide showed low Se levels and lower Se uptake and absorption efficiency than selenate. Selenium fertilization increased grain yield and altered lipid peroxidation by malondialdehyde content, hydrogen peroxide content, catalase activity, ascorbate peroxidase, superoxide dismutase, and macronutrients and micronutrients content of the studied genotypes. In sum, biofortification with selenium led to an overall yield increase of sorghum plants and supplementation with selenium through sodium selenate was more efficient than organoselenium compounds, yet acetylselenide had a positive effect on the antioxidant system. Sorghum can be effectively biofortified through the foliar application of sodium selenate; however, studying the interaction between organic and inorganic Se compounds in plants is necessary.

Selenium Organic Content Prediction in Jengkol (Archidendron pauciflorum) and Its Molecular Interaction with Cardioprotection Receptors PPAR-γ, NF-κB, and PI3K.

Selenium (Se) is a trace mineral found in plants with a distinct sulfuric odor that is cardioprotective and reported to have low toxicity. West Java, Indonesia, has a variety of plants with a distinct odor that are consumed raw, such as jengkol (Archidendron pauciflorum). This study is conducted to determine the Se content of jengkol using the fluorometric method, where the jengkol extract is separated, and the Se content is detected using high-pressure liquid chromatography (HPLC), combined with fluorometry. Two fractions with the highest Se concentration (A and B) are found and characterized using liquid chromatography mass spectrometry to predict the organic Se content by comparing the results with those in the external literature. The Se content of fraction (A) is found to be selenomethionine (m/z 198), gamma glutamyl-methyl-selenocysteine-(GluMetSeCys; m/z 313), and the Se-sulfur (S) conjugate of cysteine-selenoglutathione (m/z 475). Furthermore, these compounds are docked on receptors involved in cardioprotection. The receptors are peroxisome proliferator-activated receptor-γ (PPAR-γ), nuclear factor kappa-B (NF-κB), and phosphoinositide 3-kinase (PI3K/AKT). The interaction of receptor and ligan that has the lowest binding energy of the docking simulation is measured with molecular dynamic simulation. MD is performed to observe bond stability and conformation based on root mean square deviation, root mean square fluctuation, radius gyration, and MM-PBSA parameters. The results of the MD simulation show that the stability of the complex organic Se compounds tested with the receptors is lower than that of the native ligand, while the binding energy is lower than that of the native ligand based on the MM-PSBA parameter. This indicates that the predicted organic Se in jengkol, i.e., gamma-GluMetSeCys to PPAR-γ, gamma-GluMetSeCys AKT/PI3K, and Se-S conjugate of cysteine-selenoglutathione to NF-κB, has the best interaction results and provides a cardioprotection effect, compared to the molecular interaction of the test ligands with the receptors.

Time-Resolved Examination of Fungal Selenium Redox Transformations.

Selenium (Se) is both a micronutrient required for most life and an element of environmental concern due to its toxicity at high concentrations, and both bioavailability and toxicity are largely influenced by the Se oxidation state. Environmentally relevant fungi have been shown to aerobically reduce Se(IV) and Se(VI), the generally more toxic and bioavailable Se forms. The goal of this study was to shed light on fungal Se(IV) reduction pathways and biotransformation products over time and fungal growth stages. Two Ascomycete fungi were grown with moderate (0.1 mM) and high (0.5 mM) Se(IV) concentrations in batch culture over 1 month. Fungal growth was measured throughout the experiments, and aqueous and biomass-associated Se was quantified and speciated using analytical geochemistry, transmission electron microscopy (TEM), and synchrotron-based X-ray absorption spectroscopy (XAS) approaches. The results show that Se transformation products were largely Se(0) nanoparticles, with a smaller proportion of volatile, methylated Se compounds and Se-containing amino acids. Interestingly, the relative proportions of these products were consistent throughout all fungal growth stages, and the products appeared stable over time even as growth and Se(IV) concentration declined. This time-series experiment showing different biotransformation products throughout the different growth phases suggests that multiple mechanisms are responsible for Se detoxification, but some of these mechanisms might be independent of Se presence and serve other cellular functions. Knowing and predicting fungal Se transformation products has important implications for environmental and biological health as well as for biotechnology applications such as bioremediation, nanobiosensors, and chemotherapeutic agents.