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Objective: While sperm freezing (cryopreservation) is an effective method for preserving fertility, it can potentially harm the structure and function of sperm due to an increase in the production of reactive oxygen species. This study aimed to assess the impact of zinc oxide nanoparticles (ZnONPs) and selenium oxide nanoparticles (SeONPs) on various sperm functional parameters, including motility, plasma membrane integrity (PMI), mitochondrial membrane potential (MMP), acrosome membrane integrity (ACi), and malondialdehyde (MDA) levels. Methods: Semen samples were collected from 20 Albino Wistar rats. These samples were then divided into six groups: fresh, cryopreservation control, and groups supplemented with SeONPs (1, 2, 5 µg/mL) and ZnONPs (0.1, 1, 10 µg/mL). Results: Statistical analysis revealed that all concentrations of SeONPs increased total motility and progressive reduction of MDA levels compared to the cryopreservation control group (p<0.05). However, supplementation with ZnONPs did not affect these parameters (p>0.05). Conversely, supplements of 1 and 2 µg/mL SeONPs and 1 µg/mL ZnONPs contributed to the improvement of PMI and ACi (p<0.05). Yet, no significant change was observed in MMP with any concentration of SeONPs and ZnONPs compared to the cryopreservation control group (p>0.05). Conclusion: The findings suggest that optimal concentrations of SeONPs may enhance sperm parameters during the freezing process. [ABSTRACT FROM AUTHOR]

Bone tissue regenerative material serves as a prospective recovery candidate with self-adaptable biological properties of bio-activation, degradability, compatibility, and antimicrobial efficacy instead of metallic implants. Such materials are highly expensive due to chemical reagents and complex synthesis procedures, making them unaffordable for patients with financial constraints. This research produced an efficient bone tissue regenerative material using inexpensive naturally occurring source materials, including silica sand and limestone. The extracted SiO 2 and CaO particles (75:25 wt%) were subjected to hydrothermal synthesis (water treatment instead of chemical solvents) to produce the CaSiO 3 biomaterial (code: S). Selenium oxide was doped with calcium silicate at 3, 5, and 10 wt.% to enhance its properties, yielding biocomposite materials (i.e. S3, S5, and S10). The physico-mechanical properties of these materials were investigated with x-ray diffraction, Fourier transform infrared, FESEM-EDS, and micro-universal testing machine. The results revealed that the synthesized biocomposites have a crystalline wollastonite phase with a porously fused rough surface. From structural parametric calculations, we found that the biocomposites have reduced particle size and enhanced surface area due to the influence of selenium oxide. The biocomposite S10, having high SeO 2 content, attained the maximum compressive strength of 75.2 MPa. In-vitro studies of bioactivity, biodegradability, biocompatibility, and antibacterial activity were performed. At 7 and 14 d of bioactivity, the synthesized biocomposites are capable of dissolving their ions into simulated body fluid (SBF) solution to precipitate hydroxyapatite and a required Ca/P ratio of 1.69 was achieved by S3. A comparative analysis has been performed on the degradation activity in Tris-HCl and the consequent pH changes during SBF treatment. The bio-analysis revealed that the biocomposite S3 shows enhanced bioactivity through a controlled degradation rate and secured cell viability of 88% at a concentration of 100 μg ml -1 . It also offers significant bacterial inhibition potency against E.coli and S.aureus bacteria., (© 2023 IOP Publishing Ltd.)

Graphical abstract Highlights • Single step spray pyrolysis of nanostructured CuIn(S x Se 1−x) 2 (CISSe) thin films. • Economical and eco-friendly SeO 2 used in the spray synthesis of CISSe films. • ZnO/CdS/CISSe solar cells with 4.9% conversion efficiency fabricated. Abstract In this paper, we report the single step fabrication of nanostructured CuIn(S x Se 1−x) 2 (CISSe) thin films employing the spray pyrolysis method, using low cost precursors. To the best of our knowledge, we are the first to report the use of selenium dioxide as the source for selenium in the spray synthesis of CISSe thin films. The use of SeO 2 as the Se source makes the whole process of spray synthesis of such compounds eco-friendly and economical. X-ray diffraction (XRD) and optical transmission spectra confirm that the sprayed material is single phase CISSe with an optical band gap ∼1.25 eV. Solar cells of the type glass/FTO/ZnO/CdS/CISSe/Ag were fabricated and the best cell exhibits an AM 1.5 conversion efficiency of 4.9%. [ABSTRACT FROM AUTHOR]

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The reactions of SeO2 with a wide range of differently functionalized N‐protected indoles and pyrroles were studied in a "green" approach. The reactions occurred smoothly in ethanol at room temperature to afford 3,3′‐diindolyl and 2,2′‐dipyrrolyl selenides without any need of inert conditions. High humidity: SeO2 reacts with a wide range of differently functionalized N‐protected indoles and pyrroles to afford 3,3′‐diindolyl and 2,2′‐dipyrrolyl selenides in ethanol at room temperature without the need of inert conditions. In this "green" approach, moderate to good yields of selenylated indoles and pyrroles are obtained. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • First demonstration of promoting SeO x 2− ions immobilization using oxygen vacancies. • A high adsorptive capacity towards SeO x 2− ions was reported. • Intensively studied the adsorption mechanism of the oxygen vacancy-containing δ-Bi 2 O 3. • The bonding mode between SeO 3 2− ions and (111) plane of δ-Bi 2 O 3 has been explored. Abstract Removal of the toxic selenium compounds, selenite (SeO 3 2−) and selenate (SeO 4 2−), from contaminated water is imperative for environmental protection in both developing and industrialized countries. Providing high selectivity adsorbents to the target ions is a big challenge. Here we report that micro sphere-like δ-Bi 2 O 3 (MS-δ-Bi 2 O 3) with surface oxygen vacancy defects can capture hypertoxic SeO x 2− anions from aqueous solutions with superior capacity and fast uptake rate. High capture selectivity to SeO 3 2− anions is observed, since the O atoms of SeO 3 2− anions fill the oxygen vacancies on the (111) facet of δ-Bi 2 O 3 forming a stable complex structure. This mechanism is distinctly different from other known mechanisms for anion removal, and implies that we may utilize surface defects as highly efficient and selective sites to capture specific toxic species. Thus, we present a new route here to design superior adsorbents for toxic ions. [ABSTRACT FROM AUTHOR]

New cyano-group-containing 1,3-oxaselenoles were obtained by the treatment of aroylacetonitriles with selenium(IV) oxide. The resulting products were shown to react with ammonia, hydrazine, or primary amines; this reaction was accompanied by aryl rearrangement. [ABSTRACT FROM AUTHOR]

A set of triterpenoids with different grades of oxidation in the lupane skeleton were prepared and evaluated as cholinesterase inhibitors. Allylic oxidation with selenium oxide and Jones’s oxidation were employed to obtain mono-, di- and tri-oxolupanes, starting from calenduladiol ( 1 ) and lupeol ( 3 ). All the derivatives showed a selective inhibition of butyrylcholinesterase over acetylcholinesterase (BChE vs . AChE). A kinetic study proved that compounds 2 and 9 , the more potent inhibitors of the series, act as competitive inhibitors. Molecular modeling was used to understand their interaction with BChE, the role of carbonyl at C-16 and the selectivity towards this enzyme over AChE. These results indicate that oxidation at C-16 of the lupane skeleton is a key transformation in order to improve the cholinesterase inhibition of these compounds. [ABSTRACT FROM AUTHOR]

In this study various morphologies of ZnO including rods, disks, and nanosheets network were synthesised by electrodeposition method. The influence of the SeO 2 additive concentration on morphological, structural, and optical properties of ZnO was studied by using scanning electron microscopy, X-ray diffractometry (XRD), energy-dispersive X-ray analysis (EDX), optical (UV–Vis) and photoluminescence (PL) spectroscopy methods. The formation of the disk-like ZnO structure with a diameter of ca. 300–500 nm and thickness ca. 80–100 nm was observed when 0.03 mmol/L of SeO 2 was added to the solution. Further increase of dopant concentration up to 0.2 mmol/L in the solution yielded a highly-porous network structure composed of thin nanosheets with a wall thickness of ca. 20 nm. According to the XRD results, all structures were composed of ZnO, rod-like crystals were strongly c-axis oriented, whereas disks and nanosheets network structures were a-axis oriented. EDX analysis revealed that Se was present in the disks and nanosheets structures. PL study of the rod sample showed UV emission at ~ 370 nm, whereas the disks and nanosheets network showed intense deep-level emission band centred at ~ 540 nm. The disks and nanosheets exhibited total transmittance of ∼ 80–90% in the region of 380–780 nm, whereas transmittance of the rods was increasing from 5% to 50% in this region. According to haze factor calculations, samples possessed scattering ability of 20% for disks, 45% for sheets and ca. 50% for rods. The probable mechanism for the formation of ZnO structures was discussed in detail. [ABSTRACT FROM AUTHOR]

SnO 2 nanosheets sensitized by ZnO quantum dots were used to fabricate UV excitation gas sensors for room temperature application. The morphology and structure of the as-synthesized samples were characterized by X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. Photoluminescence spectra and UV–vis spectroscopy were used to investigate the material’s UV-excited gas sensing properties and mechanism. The results showed that the composite material with molar proportion of Zn/Sn = 0.01 (SZQ 1%) was highly sensitive to NO 2 at room temperature. The possible UV excitation gas sensing mechanism was discussed. [ABSTRACT FROM AUTHOR]

Raman and infrared spectra of the 70TeO2-(30-x)SeO2-xLi2O (x=10, 20, 30 mol%) ternary glass system have been studied. Both IR and Raman results showed that the glass network consisted of SeO3, LiO4, TeO3 and TeO4 units as basic structural groups which are building up the glass network. Addition of lithium oxide to selenium tellurite glass results in cleavage of Te-O-Te and Se-O-Se linkages and the formation of TeO3- and SeO3- terminal groups, respectively, in the present glass system. TeO4 units are gradually transformed into TeO3+1 and TeO3 units as the Li2O concentration is increased from 10 to 30 mol% in the present study. Glass structural fragments are discussed with composition of lithium oxide and selenium oxide in tellurite glass matrix. [ABSTRACT FROM AUTHOR]

We present a facile one-step hydrothermal method to in situ grow nickel selenide (Ni3Se2) nanosheets on nickel (Ni) foam (Ni3Se2/Ni) by using SeO2 as selenide source, Ni foam as nickel source and NaBH4 as reducing agent. The mole ratio of NaBH4/SeO2 is optimized as 4:1. An asymmetric supercapacitor (ASC) is fabricated by using as synthesized Ni3Se2/Ni as positive electrode and activated carbon (AC) as negative electrode. The synthesized materials and assembled devices are measured and characterized by a field emission scanning electron microscopy, powder X-ray diffraction, cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The results shows that the as-synthesized Ni3Se2/Ni electrode possesses a high specific capacitance of 854 F g−1 at 1 A g−1. The ASC can steadily operate with a high voltage of 1.6 V in 3 M KOH electrolytes, and possesses a superior energy density of 23.3 W h kg−1 at a power density of 398.1 W kg−1. In addition, the Ni3Se2//AC ASC shows excellent charge/discharge stability, after 5000 cycles the capacitance retention reaches 91.11%. The excellent performance of Ni3Se2/Ni electrode is mainly due to the pseudo-capacitive by Ni3Se2 and the 3D structure of Ni foam. [ABSTRACT FROM AUTHOR]

Structure and dielectric properties of different compositions of Ag 2 O-SeO 2 -TeO 2 mixed former glasses have been reported in this paper. Amorphous nature of the compositions has been confirmed from X-ray diffraction patterns. Thermal stability of these glasses has been investigated using differential scanning calorimetry and a connection between glass transition temperature and cross-linking density has been established. Fourier transform infrared (FTIR) spectroscopy has been used to investigate the effect of SeO 2 on the glass network structure, and the existence of different structural units, such as TeO 4 , TeO 3 and SeO 3 2 − has been ascertained. The composition dependence of the relative proportion of these structural units has been studied. Dielectric spectra have been analyzed using Cole-Cole model. The relaxation time obtained from the analysis exhibits Arrhenius behavior. The activation energy for the relaxation time shows mixed glass former effect. Further, dielectric properties of these glasses have been correlated with the polarizability along with the optical basicity of these glasses. [ABSTRACT FROM AUTHOR]

Despite its wide use in the display and photovoltaic industries, fluorine-doped tin oxide (F:SnO 2 , FTO) has been studied only in its polycrystalline form. In this work, we report on the first growth of epitaxial FTO thin film by ultrasonic spray pyrolysis – a simple chemical deposition method – and we reveal the structure-property interplay by investigating in details its growth, morphology and strain/defects. Epitaxial FTO films are successfully grown on (110) rutile TiO 2 single crystals and form mosaic domains with an out-of-plane distribution smaller than 0.5°, showing high structural quality comparable to epitaxial films prepared by molecular beam epitaxy and pulsed-laser deposition. Owing to the large lattice mismatch with rutile TiO 2 , the FTO film develops significant structural defects to release the epitaxial strain and is consequently nearly fully relaxed with a slight residual strain of 0.1–0.2%. With the help of an innovative nano-beam precession electron diffraction technique, the strain distribution is mapped at the TiO 2 /FTO interface, from which we identify the interfacial and secondary strain relaxation taking place mainly in the first 22 nm in the FTO film. The Hall-mobility of the epitaxial FTO films is close to the state-of-the-art and expected to improve further at lower doping concentrations. [ABSTRACT FROM AUTHOR]

Two new dialkyammonium selenate salts [i-Pr2NH2]2[SeO4] (1) and [n-Bu2NH2][HSeO4] (2) have been isolated and characterized by single-crystal X-ray diffraction. Salt 1 crystallizes in the monoclinic system, space group P21/n with a = 8.7190(5), b = 8.8500(4), c = 22.5953(9) Å, β = 94.6290(17)°, V = 1737.84(14) Å3 and Z = 4. Salt 2 crystallizes in the monoclinic system space group P21/n with a = 10.9328(9), b = 8.1700(6), c = 13.8095(11) Å, β = 97.130(3)°, V = 1223.94(17) ų and Z = 4. In both salts, dialkylammonium cations and selenate anions are connected through NH · · · O and OH · · · O hydrogen bonds. In the crystal structure, 1 and 2 are organized in layer-like arrangements. Structural characterizations were completed by infrared and ¹H, 13C{1H} and 77Se NMR spectroscopy and elemental analysis which corroborate the X-ray elucidations. [ABSTRACT FROM AUTHOR]

The thermoelectric properties and electronic structures were investigated on p -type BiCu 1- x Ag x SeO ( x =0, 0.02, 0.05, 0.08) ceramics prepared using a two-step solid state reaction followed by inductively hot pressing. All the samples consist of single BiCuSeO phase with lamella structure and no preferential orientation exists in the crystallites. Upon replacing Cu + by Ag + , maximum values of electrical conductivity of 36.6 S cm −1 and Seebeck coefficient of 350 μV K −1 are obtained in BiCu 0.98 Ag 0.02 SeO and BiCu 0.92 Ag 0.08 SeO, respectively. Nevertheless, a maximum power factor of 3.67 μW cm −1 K −2 is achieved for BiCu 0.95 Ag 0.05 SeO at 750 K owing to the moderate electrical conductivity and Seebeck coefficient. Simultaneously, this oxyselenide exhibits a thermal conductivity as low as 0.38 W m −1 K −1 and a high ZT value of 0.72 at 750 K, which is nearly 1.85 times as large as that of the pristine BiCuSeO. The enhancement of thermoelectric performance is mainly attributed to the increased density of states near the Fermi level as indicated by the calculated results. [ABSTRACT FROM AUTHOR]

An SeO2-mediated one-pot method was established for the synthesis of 3-cyanofurans from 3-oxo-3-arylpropanenitriles and substituted acetaldehydes. The generality of the reaction was explored, and a plausible mechanism is proposed. [ABSTRACT FROM AUTHOR]

Recent experiments have revealed that the p- type BiCuSeO-based oxychalcogenides compounds exhibit a high thermoelectric figures of merit due to their very low lattice thermal conductivities and moderate Seebeck coefficient in the medium temperature range. In the present work, we reported on the optoelectronic and thermoelectric properties using the full potential linear augmented plane wave method and modified Becke-Johnson potential with spin-orbit coupling. The properties show that the BiCuSeO-based oxychalcogenides exhibit a semiconductor behavior with band gap values of 0.51, 0.45 and 0.41 eV for BiCuSO, BiCuSeO, and BiCuTeO, respectively. Due to their prominent role for thermoelectric applications, we combined Boltzmann transport theory to DFT results to compute the transport properties, mainly electronic conductivity, thermal conductivity, Seebeck coefficient and power factor. The present results show the dominance of BiCuTeO for thermoelectric application compared to the BiCuSO and BiCuSeO. [ABSTRACT FROM AUTHOR]

Small, red Fe2SeO single crystals in two modifications were obtained from a CsCl flux. The metastable α-phase is pseudo-tetragonal (Cmce, a=16.4492(8) Å, b=11.1392(4) Å, c=11.1392(4) Å), whereas the β-phase is trigonal (P31, a=9.8349(4) Å, c=6.9591(4) Å)) and thermodynamically stable within a narrow temperature range. Both crystal structures were solved from twinned specimens. The enantiomers of the β-phase appear as racemic mixtures. Selenium and oxygen form two individual interpenetrating primitive cubic lattices, giving a bcc packing. A quasi-octahedrally coordinated iron atom is found close to the center of each surface of the selenium sublattice. The difference between the α- and β-phases is the distribution of iron at 2/3 of the surfaces. α- and β-Fe2SeO are comparable with metal-vacancy-ordered antiperovskites. Each Fe/O lattice can also be described in terms of vertex-sharing OFe4 tetrahedra, with a crystal structure similar to that of an antisilicate. Iron is divalent and has a high-spin d6 ( S=2) configuration. The β-phase exhibits magnetoelectric coupling. [ABSTRACT FROM AUTHOR]

Seven isomorphous alkali metal lanthanide selenites, Na4Ln4(SeO3)7O·nH2O (Ln = Gd, Tb, Dy, Ho, Er, Tm, and Yb), exhibiting a new structure type, have been prepared by hydrothermal methods. The four crystallographically unique Ln3+ cations within the structure exhibit three different coordination environments that are best described as bicapped trigonal prisms, trigonal dodecahedra, and pentagonal bipyramids. These polyhedra edge- and corner-share to yield diamond-shaped channels that extend along the a axis and are approximately 8.4 Å × 10.5 Å. These channels house alkali metal cations and disordered water molecules. The Ho-analog was chosen for ion-exchange studies that indicate that the Na+ cations in the channels can be selectively exchanged for Rb+, but ion exchange with other monovalent cations does not occur. [ABSTRACT FROM AUTHOR]

Water pollution is an issue that should be carefully monitored and addressed. A major source of water pollution originates from high temperature industrial processes such as fossil fuel combustion and solid waste incineration. This waste typically contains high levels of oxyanion/cation forming elements which are particularly hazardous due to their inherent solubility in water and their resulting bioavailability. One approach for oxyanion/cation removal from water involves using an adsorbing medium to soak up and remove pollutants. Metal–organic frameworks (MOFs) offer an interesting platform for water remediation. MOFs are structurally diverse, porous materials that are constructed from metal nodes bridged by organic ligands. This highlight will focus on oxyanion/cation (PO43−, AsO43−, SeO32−, SeO42−, UO22+) removal from aqueous solutions using MOFs as contaminant-selective sponges. The mechanism of adsorption in different frameworks will be explored to gain insight into some design features that are important for MOFs to be used in applications to help alleviate water pollution. [ABSTRACT FROM AUTHOR]

Combined high catalytic activity and thermal stability were achieved with a well-structured, surfactant-free Pd@porous SiO2 yolk–shell nanostructure, resulting from the entirely exposed Pd core particles and highly porous silica shells. Pd@SiO2 core–shell nanoparticles were synthesized by a water-in-oil microemulsion method for direct silica coating of as-prepared tiny Pd nanoparticles. Hydrothermal etching and subsequent high thermal treatment generated large pores in the silica shells and facilitated complete removal of surfactants around the core particles. The surfactant-free Pd@pSiO2 yolk–shell nanoparticles efficiently catalyzed the oxidation of benzyl alcohol as well as that of various substituted benzyl alcohols. [ABSTRACT FROM AUTHOR]

A pulsed potential method was used to synthesize chalcopyrite CuInSe 2 films by a single step electrodeposition process from acidic aqueous solutions of Cu(II) and In(III) nitrates, selenium oxide (SeO 2 ) and citrate (C 6 H 5 Na 3 O 7 ) additive. The effect of deposition parameters, such as bath composition, pulsed potential profile, electrolysis charge, and bath temperature, on the structure, composition and morphology of the obtained films was investigated. Conditions for producing coherently uniform deposits with near stoichiometric compositions were specified. Pulse plating at room temperature from pH 1.6–1.8 baths with millimolar concentrations of precursors, and a five to ten-fold excess of In(III) over Cu(II), employing the moderately high frequency of 1 Hz and short cathodic pulses, was found leading to direct formation of CuInSe 2 crystallites in strongly (112) tetr -textured films, free from bulk secondary phases. [ABSTRACT FROM AUTHOR]

A variety of selenium compounds were proven to be useful reagents and catalysts for organic synthesis over the past several decades. The most interesting aspect, which emerged in recent years, concerns application of hydroperoxide/selenium(IV) oxide and hydroperoxide/organoselenium catalyst systems, as "green reagents" for the oxidation of different organic functional groups. The topic of oxidations catalyzed by organoselenium derivatives has rapidly expanded in the last fifteen years This paper is devoted to the synthetic applications of the oxidation reactions mediated by selenium compounds such as selenium(IV) oxide, areneseleninic acids, their anhydrides, selenides, diselenides, benzisoselenazol-3(2H)-ones and other less often used other organoselenium compounds. All these compounds have been successfully applied for various oxidations useful in practical organic syntheses such as epoxidation, 1,2-dihydroxylation, and a-oxyfunctionalization of alkenes, as well as for ring contraction of cycloalkanones, conversion of halomethyl, hydroxymethyl or active methylene groups into formyl groups, oxidation of carbonyl compounds into carboxylic acids and/or lactones, sulfides into sulfoxides, and secondary amines into nitrones and regeneration of parent carbonyl compounds from their azomethine derivatives. Other reactions such as dehydrogenation and aromatization, active carbon-carbon bond cleavage, oxidative amidation, bromolactonization and oxidation of bromide for subsequent reactions with alkenes are also successfully mediated by selenium (IV) oxide or organoselenium compounds. The oxidation mechanisms of ionic or free radical character depending on the substrate and oxidant are discussed. Coverage of the literature up to early 2015 is provided. Links have been made to reviews that summarize earlier literature and to the methods of preparation of organoselenium reagents and catalysts. [ABSTRACT FROM AUTHOR]

Recent reports of As concentrations in certain food and drinks have garnered public concern and led to a lowering of the US guideline maximum concentration for inorganic As in apple juice and proposed limits for As in rice products. In contrast Se is an essential micro-nutrient that can be limiting when Se-poor soils yield Se-poor food crops. Rare earth element (REE) doubly charged interferences on As and Se can be significant even when initial ICP-MS tuning minimizes doubly charged formation. We analyzed NIST 1547 (peach leaves) and 1515 (apple leaves), which contain high levels of REEs, by quadrupole ICP-MS with (He) collision mode, H2 reaction mode or triple quadrupole ICP-MS (ICP-QQQ) in mass-shift mode (O2 and O2/H2). Analysis by collision cell ICP-MS significantly over-estimated As and Se concentration due to REE doubly charged formation; mathematical correction increased the accuracy of analysis but is prone to error when analyte concentration and sensitivity is low and interferent is high. For Se, H2 reaction mode was effective in suppressing Gd2+ leading to accurate determination of Se in both SRMs without the need for mathematical correction. ICP-QQQ using mass-shift mode for As+ from m/z 75 to AsO+ at m/z 91 and Se+ from m/z 78 to SeO+ at m/z 94 alleviated doubly charged effects and resulted in accurate determination of As and Se in both SRMs without the need for correction equations. Zr and Mo isobars at 91 and 94 were shown to be effectively rejected by the MS/MS capability of the ICP-QQQ. [ABSTRACT FROM AUTHOR]

Purpose: Selenium (Se) adsorption influences its mobility, transformation, and bioavailability in soil. Se interactions with soils and soil constituents have focused primarily on selenite retention. The dominant factors of selenite adsorption behavior and the impacts of exogenous Se concentration were investigated for the prediction of the rate of retention and release of selenium species in soils and the guidance of Se supplementation implementation. Materials and methods: Eighteen typical agricultural soils with varying physicochemical characteristics and mineralogical composition were collected throughout China for the study of their adsorption and desorption behavior toward selenite and the effect of their physicochemical properties. Results and discussion: Results showed that Se adsorbances among 18 soils varied considerably. Among numerous soil properties and components, soil pH exerted a significant negative effect on selenite adsorption in soil, whereas amorphous iron and amorphous aluminum had positive effect ( P < 0.05). Organic matter (OM) showed an indirect effect when high concentrations of selenite were present in soil. Moreover, soil carbonate content imposed an indirect effect on selenite adsorption in soil. Selenite desorption showed a reverse trend compared with adsorption: the correlations of desorption rate with soil pH and amorphous iron were positive and negative, respectively ( P < 0.05). The soil/solution distribution coefficient ( K) had no significant correlation with soil properties, other than with pH ( P < 0.05), but the K values of different soils were highly variable. Conclusions: The observed adsorption behavior of selenite in soil is complicated: small amounts of exogenous Se were mainly adsorbed by a monolayer physical process, but multilayer adsorption occurred when the concentration increased. The soils that strongly adsorb selenite often showed low desorption rates, as well, which largely limited the migration, transformation, and bioavailability of selenite in soils. Therefore, residue problem must be considered when Se fertilizers are applied to these soils. [ABSTRACT FROM AUTHOR]

Lentil (Lens culinaris Medik), a nutritious traditional pulse crop, has been experiencing a declining area of production in South East Asia, due to lower yields, and marginal soils. The objective of this study was to determine whether selenium (Se) fertilization can increase lentil yield, productivity, and seed quality (both seed Se concentration and speciation). Selenium was provided to five lentil accessions as selenate or selenite by foliar or soil application at rates of 0, 10, 20, or 30 kg Se/ha and the resulting lentil biomass, grain yield, seed Se concentration, and Se speciation was determined. Seed Se concentration was measured using inductively coupled plasma optical emission spectrometry (ICP-OES) after acid digestion. Seed Se speciation was measured using ICP-mass spectrometry with a high performance liquid chromatography (ICP-MS-LC) system. Foliar application of Se significantly increased lentil biomass (5586 vs. 7361 kg/ha), grain yield (1732 vs. 2468 kg /ha), and seed Se concentrations (0.8 vs. 2.4 μg/g) compared to soil application. In general, both application methods and both forms of Se increased concentrations of organic Se forms (selenocysteine and selenomethionine) in lentil seeds. Not surprisingly, the high yielding CDC Redberry had the highest levels of biomass and grain yield of all varieties evaluated. Eston, ILL505, and CDC Robin had the greatest responses to Se fertilization with respect to both grain yield, seed Se concentration and speciation; thus, use of these varieties in areas with low-Se soils might require Se fertilization to reach yield potentials. [ABSTRACT FROM AUTHOR]

The PbO-NiO-SeO2 ternary system was fully studied using constant hydrothermal conditions at 473 K. It yields the establishment of the corresponding phase diagram using a systematic assignment of reaction products by both powder and single-crystal X-ray diffraction. It leads to the preparation of three novel lead nickel selenites, α-PbNi(SeO3)2 (I), β-PbNi(SeO3)2 (II), and PbNi2(SeO2OH)2(SeO3)2 (III), and one novel lead cobalt selenite, α-PbCo(SeO3)2 (IV), which have been structurally characterized. The crystal structures of the α-forms I, IV, and III are based on a 3D complex nickel selenite frameworks, whereas the β-PbNi(SeO3)2 modification (II) consists of nickel selenite sheets stacked in a noncentrosymmetric structure, second-harmonic generation active. The pH value of the starting solution was shown to play an essential role in the reactive processes. Magnetic measurements of I, III, and IV are discussed. [ABSTRACT FROM AUTHOR]

A short and convenient synthesis of fused 1,2,5-selenadiazoles from the corresponding 1,2,5-thiadiazoles and selenium dioxide has been developed. [ABSTRACT FROM AUTHOR]

The present paper reports the chemical synthesis, structure study, thermal analysis, and vibrational properties of new hybrid compound called: bis (adeninium) selenate bihydrates. It is crystallized in the triclinic system with P-1 space group and the following parameters a = 7.804(5) Å; b = 9.686 (5) Å; c = 11.771 (5) Å; α = 84.421(5)°; ß = 77.556(5)°; γ = 81.186 (5)°; Z = 2 and V = 856.7(8) Å 3 . The structure is built up from tunnels containing all the components of the structure and following to the c axis, linked via three types of hydrogen bonds (N H…O, N H…N and O H…O). The thermal decomposition of precursors studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), indicate the existence of two mass loss region correspond to dehydration and degradation of the title compound, respectively. The existence of vibrational modes correspond to the organic and inorganic groups and water molecular are identified by the IR and Raman spectroscopy in the frequency ranges 400–4000 and 300–1600 cm −1 , respectively. [ABSTRACT FROM AUTHOR]

The sorption of Se(IV) and Se(VI) on uranium peroxide has been studied considering the sorption kinetics, the sorption isotherms and the effect of pH. Selenium sorption on studtite is fitted with a pseudosecond order reaction model; in addition, two different mechanisms seem to influence the sorption process: micropore diffusion and intra-particle diffusion. Both selenium(IV) and selenium(VI) are sorbed on studtite through a monolayer coverage. Sorption is higher at acidic pH than at alkaline pH. This behaviour is consistent with the chemical speciation of selenium in solution and with the acid-base properties of the solid. [ABSTRACT FROM AUTHOR]

Zinc selenide thin films on ITO glass substrate have been grown by an electrochemical deposition technique at a low temperature of 50°C. The bath solution was maintained at three different pH values and the effect of pH on the nature of the deposited films studied. Profilometer studies showed the roughness of ZnSe thin films obtained from the bath in which SeO2 was the Se source is lower than that of the films obtained from the bath in which SeCL4 was the Se source. The atomic percentage ratio for zinc and selenium of the ZnSe thin films obtained from the bath in which SeO2 was the Se source was found to be 49.7:50.3. GAXRD studies confirmed that the as-deposited ZnSe thin films belong to the cubic system with (111) plane as the dominant peak. When SeCl4 was used as Se source the thin films showed peaks due to the cubic system along with hexagonal (100) reflection indicating a mixed phase. The absorption coefficient's fall is sharper for the films obtained from the bath in which SeO2 was the Se source than those films obtained from the bath in which SeCl4 was the Se source due to the presence of hexagonal phase. [ABSTRACT FROM AUTHOR]