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Tellurium nanoparticles (TeNPs) are emerging as valuable materials in various technological and biomedical applications due to their unique physicochemical properties. In general, TeNPs are prepared using chemical methods based on a redox reaction in which strong reducing agents are employed which are often toxic and harmful to the environment. Biological biosynthesis provides a green strategy for substituting the commonly used reducing chemical agents with microorganisms or enzymes. Among the enzymes noted as key players in microbial tellurite reduction, glutathione reductase (GR) has been identified; however, its specific role in enhancing TeNP biosynthesis has yet to be fully elucidated. In this study, we aimed to evaluate the impact of GR overexpression on TeNP production in Escherichia coli (E. coli). For this purpose, four GR enzymes from different microorganisms identified as tellurite resistant were heterogeneously expressed and purified from E. coli. The kinetic parameters for NADPH and oxidized glutathione (GSSG), the native substrates of GR, were determined to evaluate their TR activity under saturated NADPH concentrations. The GR from Pseudomonas lini strain BNF22 presented the highest catalytic efficiency for NADPH and exhibited greater TR activity. This enzyme was overexpressed in E. coli MG1655 (DE3) and cells overexpressing GR increased the yield of TeNPs in those cells, presenting an increased elemental cell tellurium composition. Our results provide valuable insights for the development of engineered E. coli as a platform for TeNP biosynthesis. Using microorganisms as a green strategy for TeNP production, the results of this study highlight the enzymatic mechanisms underlying the role of GR in the biosynthesis of TeNPs. [ABSTRACT FROM AUTHOR]

Stibnite (Sb2S3) is an important but difficult to biologically leach mineral, so it is important to find a potential scheme for improving the bioleaching rate of Sb2S3. In this study, by combining experiments and first-principles density functional theory (DFT) calculations, the impact and related mechanisms of pyrite (FeS2) on stibnite (Sb2S3) bioleaching were studied for the first time. The bioleaching results revealed that FeS2 obviously improved the Sb2S3 bioleaching rate, and in the 0.5FeS2:0.5CuFeS2 system, the bioleaching rate of Sb2S3 increased from 2.23 to 24.6%, which was the best mass mixing ratio. The XPS and XANES results revealed that during the bioleaching process, Sb2S3 was transformed to Sb2O3 and Sb2O5. The electrochemical results revealed that after FeS2 was mixed, a FeS2-Sb2S3 galvanic cell formed, which promoted the electron transfer efficiency and redox reaction of Sb2S3. The DFT results show that between the Sb2S3 (0 1 0) and FeS2 (1 0 0) surfaces, S-Fe, S-S, S-Sb, and Sb-Fe bonds are formed, and the direction of electron transfer is from Sb2S3 to FeS2; the work functions for Sb2S3 after addition of FeS2 decrease, implying that faster electron transfer occurs; Fe(III)-6H2O derived from FeS2 adsorbs on the surface more easily than does glucose, which is the major component of the extracellular polymeric substances in bacteria, indicating that during the bioleaching process, Fe(III)-6H2O plays an important role; after mixing, both Fe(III)-6H2O and glucose adsorb on the Sb2S3 (0 1 0) surface more easily, with stronger bonds and larger adsorption energies, which are in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

Tellurium, recognized as one of the technology-critical elements, should be considered as a xenobiotic. Its application, i.a. in the growing photovoltaic industry, raises concerns about Te(IV) and Te(VI) release to the environment. As both forms differ in mobility and toxicity, Te speciation should be included in water monitoring, but problems with speciation changes occurring during sampling, transport, and sample storage require the use of on-site separation of Te forms. A simple procedure based on solid phase extraction (SPE) with the anionic exchange mechanism (SAX, involving commercially available columns), followed by their quantification with elemental techniques, has a high potential for implementation in routine analysis. The proposed SPE-ICP-MS (inductively coupled plasma mass spectrometry) method allows direct analysis of Te(VI) and Te(IV), with Te(IV) determined after elution from the column. The detection limits obtained for the 5.0 mL sample are 0.02 ng mL−1 and 0.05 ng mL−1 for Te(VI) and Te(IV), respectively. Hydride generation inductively coupled plasma optical emission spectrometry (HG-ICP-OES) was used to control possible changes in tellurium speciation occurring during species isolation using SPE. The simple and fast water pretreatment proposed here offers the possibility of separating Te(IV) and Te(VI) at the sampling site, and the elution of Te(IV) does not have to be conducted on-site. Application to the river water and seawater matrix proved the feasibility of incorporating Te speciation analysis into routine water analysis. [ABSTRACT FROM AUTHOR]

Bismuth ferrite (BiFeO3) possesses multifunctional properties pertaining to its unique crystal structure. This study presents a comprehensive investigation on the role of different chelating agents on the low temperature, sol-gel synthesis of bismuth ferrite (BFO) nanoparticles (NPs). The sol-gel process utilizes precursors (iron nitrate and bismuth nitrate), solvent (ethylene glycol), catalyst (nitric acid), and the chelating agent. In this work, different chelating agents, such as acetic acid (AA), citric acid (CA), ethylenediaminetetraacetic acid (EDTA), glycine (GLY), tartaric acid (TA), and urea are evaluated for their influence on the phase purity and morphological features of the synthesized BFO. The NPs are characterized using various techniques such as x-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area analysis, UV-Vis-NIR spectroscopy, and vibrating sample magnetometry (VSM). Among all the chelating agents, TA is found to be the most suitable candidate for BFO synthesis. Pure BFO NPs of average crystallite size 20.8 nm, 24.8 m2/g surface area, and 1.91 eV optical bandgap are obtained after the calcination of the BFO-TA gel. The results are attributed to the easy gelation capability of TA due to the formation of a well-organized heterometallic polynuclear network during the gelation process. High magnetic saturation of 6.72 emu/g and squareness ratio of 0.26 of BFO-TA NPs implies a weak ferromagnetic nature. These results demonstrate a promising route to synthesize pure BFO, which given its multiferroic nature can be used for many applications. Highlights: Bismuth ferrite (BFO) synthesized by sol-gel process using different chelating agents Tartaric acid was found to be most suitable for obtaining pure BFO Structural, optical, and magnetic characterization was performed for the synthesized BFO The synthesized BFO finds applicability in photocatalytic dye degradation [ABSTRACT FROM AUTHOR]

In order to recover the antimony from wastewater, a custom-designed fluidized-bed reactor (FBR) was employed to treat antimony-containing wastewater. By single-factor experiments, the effects of the solution pH, the molar ratio of [TA]/[Sb3+], the seed size and dosage, the up-flow velocity (U), and the hydraulic retention time (HRT) on antimony recovery were investigated based on the antimony removal and granulation efficiency. The optimum conditions for antimony recovery were obtained at pH 9.0, the molar ratio of [TA]/[Sb3+] of 2, 6 g/L of 13–38 μm Sb2O3 as the fluidized seed, and the U and HRT of 42 m/h and 40 min, respectively; the antimony removal and granulation efficiency reached 95% and 91%, respectively. The granular products were analyzed by an X-ray polycrystalline diffractometer (XRD) and scanning electron microscopy (SEM) as cubic Sb2O3, widely used in various industries. The fluidized-bed reactor was operated continuously for 7 days, during which the antimony removal and granulation efficiency were stable at 96% and 93%, respectively. This study demonstrated the feasibility of the fluidized-bed granulation process for the recovery of antimony from wastewater. It provides a novel approach for retrieving and managing antimony-containing wastewater. [ABSTRACT FROM AUTHOR]

This research, focusing on the environmental impact of tire and brake disc pad wear, constitutes a significant area of transport-related studies. These two key vehicle components are not only the most frequently worn but also generate micro- and nano-pollutants (i.e., rubber, metal oxides) that potentially harm the environment. Over half of the globally produced natural and synthetic rubbers, which amounted to about 30 million tons in 2022, are used for tire production. This work focuses on the study of roadside snow, sand, and standing water deposits from various locations in the urban agglomeration (Poznań, Poland) during the winter season, determining their qualitative composition and the quantitative content of pollutants originating from tire abrasion. In addition, the method of washing nano- and micro-rubber particles and their full characteristics was also presented. Fourier-transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopic studies, optical and scanning electron microscopy (SEM-EDS), particle size studies using a dynamic light scattering (DLS) particle analyzer, and thermogravimetric analysis (TGA) were conducted for a detailed characterization of the pollutants in the environment. The conducted particle separation methods allowed for the extraction of a fraction mainly containing gum residues with particle sizes less than 2 µm. The results of these tests make it possible to estimate the level of contamination with rubber and metal residues during the abrasion of tires, pads, and brake discs while driving, which is crucial for understanding the impact of vehicle part exploitation on the environment. [ABSTRACT FROM AUTHOR]

Radiation protection is an essential issue in diagnostic radiology to ensure the safety of patients, healthcare professionals, and the general public. Lead has traditionally been used as a shielding material due to its high atomic number, high density, and effectiveness in attenuating radiation. However, some concerns related to the long-term health effects of toxicity, environmental disease as well as heavy weight of lead have led to the search for alternative lead-free shielding materials. Lead-free multilayered polymer composites and non-lead nano-composite shields have been suggested as effective shielding materials to replace conventional lead-based and single metal shields. Using several elements with high density and atomic number, such as bismuth, barium, gadolinium, and tungsten, offer significant enhancements in the shielding ability of composites. This review focuses on the development and use of lead-free materials for radiation shielding in medical settings. It discusses the drawbacks of traditional lead shielding, such as toxicity, weight, and recycling challenges, and highlights the benefits of lead-free alternatives. [ABSTRACT FROM AUTHOR]

Tellurium (Te) is the heaviest stable chalcogen and is a rare element in Earth's crust (one to five ppb). It was discovered in gold ore from mines in Kleinschlatten near the present-day city of Zlatna, Romania. Industrial and other applications of Te focus on its inorganic forms. Tellurium can be toxic to animals and humans at low doses. Chronic tellurium poisoning endangers the kidney, liver, and nervous system. However, Te can be effective against bacteria and is able to destroy cancer cells. Tellurium can also be used to develop redox modulators and enzyme inhibitors. Soluble salts that contain Te had a role as therapeutic and antimicrobial agents before the advent of antibiotics. The pharmaceutical use of Te is not widespread due to the narrow margin between beneficial and toxic doses, but there are differences between the measure of toxicity based on the Te form. Nano-tellurium (Te-NPs) has several applications: it can act as an adsorptive agent to remove pollutants, and it can be used in antibacterial coating, photo-catalysis for the degradation of dyes, and conductive electronic materials. Nano-sized Te particles are the most promising and can be produced in both chemical and biological ways. Safety assessments are essential to determine the potential risks and benefits of using Te compounds in various applications. Future challenges and directions in developing nano-materials, nano-alloys, and nano-structures based on Te are still open to debate. [ABSTRACT FROM AUTHOR]

The main objective of this study is to map multi-element geochemical anomalies in soil on a regional scale. We aimed to determine and evaluate the baseline geochemical values and main geochemical trends in soil that may serve as reference values against any future changes. A total of 817 topsoil samples (0–10 cm) were collected in a 5 × 5 km grid and analyzed for 35 elements using ICP-ES after multi-acid digestions (HClO4/HNO3/HCl/HF) and 53 elements using ICP-MS after modified aqua regia digestion (HCl/HNO3/H2O). The analytical results for the two different digestion methods (multi-acid digestion vs. aqua regia) were also compared for each chemical element. Multivariate statistical methods were applied to identify the geochemical trends and main sources of trace elements over the territory of Slovenia. Based on these results, seven natural and one mixed natural/anthropogenic geochemical association were established. The contents and trends of the determined factors are presented according to 8 natural units, 4 drainage areas, and geological units characteristic of Slovenia. The identified anthropogenic geochemical association combines toxic elements (Ag, Bi, Cd, Hg, P, Pb, S, Sn, and Zn). Increased values of these elements can be found in mining areas and metallurgic centers, in Quaternary sediments of the Sava River, and Adriatic Basin as the consequence of past mining activities and in the Julian Alps, where their origin could be connected to the atmospheric deposition. [ABSTRACT FROM AUTHOR]

Marine Co-rich ferromanganese crusts and polymetallic nodules, which are widely distributed in oceanic environments, are salient potential mineral resources that are enriched with many critical metals. Many investigations have achieved essential progress and findings regarding critical metal enrichment in Fe-Mn crusts and nodules. This study systematically reviews the research findings of previous investigations and elaborates in detail on the enrichment characteristics, enrichment processes and mechanisms and the influencing factors of the critical metals enriched in Fe-Mn crusts and nodules. The influencing factors of critical metal enrichments in Fe-Mn crusts and nodules mainly include the growth rate, water depth, post-depositional phosphatization and structural uptake of adsorbents. The major enrichment pathways of critical metals in marine Fe-Mn (oxy)hydroxides are primarily as follows: direct substitution on the surface of δ-MnO2 for Ni, Cu, Zn and Li; oxidative substitution on the δ-MnO2 surface for Co, Ce and Tl; partition between Mn and Fe phases through surface complexation according to electro-species attractiveness for REY (except for Ce), Cd, Mo, W and V; combined Mn-Fe phases enrichment for seawater anionic Te, Pt, As and Sb, whose low-valence species are mostly oxidatively enriched on δ-MnO2, in addition to electro-chemical adsorption onto FeOOH, while high-valence species are likely structurally incorporated by amorphous FeOOH; and dominant sorption and incorporation by amorphous FeOOH for Ti and Se. The coordination preferences of critical metals in the layered and tunneled Mn oxides are primarily as follows: metal incorporations in the layer/tunnel-wall for Co, Ni and Cu; triple-corner-sharing configurations above the structural vacancy for Co, Ni, Cu, Zn and Tl; double-corner-sharing configurations for As, Sb, Mo, W, V and Te; edge-sharing configurations at the layer rims for corner-sharing metals when they are less competitive in taking up the corner-sharing position or under less oxidizing conditions when the metals are less feasible for reactions with layer vacancy; and hydrated interlayer or tunnel-center sorption for Ni, Cu, Zn, Cd, Tl and Li. The major ore-forming elements (e.g., Co, Ni, Cu and Zn), rare earth elements and yttrium, platinum-group elements, dispersed elements (e.g., Te, Tl, Se and Cd) and other enriched critical metals (e.g., Li, Ti and Mo) in polymetallic nodules and Co-rich Fe-Mn crusts of different geneses have unique and varied enrichment characteristics, metal occurrence states, enrichment processes and enrichment mechanisms. This review helps to deepen the understanding of the geochemical behaviors of critical metals in oceanic environments, and it also bears significance for understanding the extreme enrichment and mineralization of deep-sea critical metals. [ABSTRACT FROM AUTHOR]

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Background: Natural and anthropogenic activities, such as weathering of rocks and industrial processes, result in the release of toxic oxyanions such as selenium (Se) and tellurium (Te) into the environment. Due to the high toxicity of these compounds, their removal from the environment is vital. Results: In this study, two yeast strains, Yarrowia lipolytica and Trichosporon cutaneum, were selected as the superior strains for the bioremediation of tellurium and selenium. The reduction analyses showed that exposure to selenite induced more detrimental effects on the strains compared to tellurite. In addition, co-reduction of pollutants displayed almost the same results in selenite reduction and more than ~ 20% higher tellurite reduction in 50 h, which shows that selenite triggered higher tellurite reduction in both strains. The selenite and tellurite kinetics of removal were consistent with the first-order model because of their inhibitory behavior. The result of several characterization experiments, such as FE-SEM (Field emission scanning electron microscopy), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), and dispersive X-ray (EDX) on Te–Se nanoparticles (NPs) revealed that the separated Te–Se NPs were needle-like, spherical, and amorphous, consisted of Te–Se NPs ranging from 25 to 171 nm in size, and their surface was covered with different biomolecules. Conclusions: Remarkably, this work shows, for the first time, the simultaneous bioreduction of tellurite and selenite and the production of Te–Se NPs using yeast strains, indicating their potential in this area, which may be applied to the nanotechnology industry and environmental remediation. Highlights: First report of co-contaminant reduction of tellurite and selenite by yeast strains. Higher bioremediation efficiency of co-contaminant cultures than separate cultures. In co-contaminant cultures, selenite triggered higher tellurite reduction for both strains. Bioreduction of toxic tellurite and selenite to valuable Te–Se nanoparticles. Characterization of biosynthesized Te–Se nanoparticles. [ABSTRACT FROM AUTHOR]

To increase the sustainability of footwear and align it with the circular bioeconomy, there is a pressing need to develop novel bio-based materials to replace the synthetic polymers currently used. In this study, casein-based films were prepared by solution casting with a tannic acid cross-linker, and a glycerol plasticizer. The properties important to footwear materials were characterised, including tensile strength and elongation, stitch strength, hardness, grain cracking strength, water vapour permeability, and thermal properties. The tannic acid imparted a brown colour to the films with good resistance to light-induced fading. Their tensile strengths were 4–5 N/mm2, elongation at break 45%–73%, and water vapour permeability 0.2–0.6 mg/(cm2h), depending upon the levels of the cross-linker and plasticiser. The strength of the films was close to those of some non-leather footwear materials such as compact rubbers and insock materials, but below that required for leather shoe vamps/uppers. The casein films were successfully used in sneaker- and ballerina-style shoes as components of the insock and decorative design elements on the vamp. This work has demonstrated the concept of using casein films in footwear. The properties of the films could be improved by further research, particularly with respect to cross-linking, plasticizing, and combining with bio-based fibers and fabrics. [ABSTRACT FROM AUTHOR]

Tomiolloite (IMA2021-019) is a new aluminum tellurite sulfite-sulfate mineral discovered at the Bambolla mine, Moctezuma, Sonora, Mexico, a well-known tellurium (Te) mineral locality. Tomiolloite forms roughly spherical clusters of crystals comprised of very thin, needle-like crystals (1 μm diameter, ~40 μm length) around a core of small, stubbier, broken crystals. Tomiolloite is generally found growing on tellurite or quartz. The strongest powder X‑ray diffraction lines are [dobs Å (Iobs) (hkl)]: 11.667 (89) (100), 8.240 (38) (101), 4.107 (29) (202,211,121), 3.223 (100) (203,302,130), and 2.905 (37) (213,123,222,400). The empirical formula of tomiolloite, as determined by electron microprobe analysis, is (Al10.64Te61.01+ Fe30.31+ Zn0.04)Σ12(Te45.00+ Pb0.02)Σ5.02(S40.49+ S60.49+ Si0.02)Σ1.00O21.53[(OH)20.86Cl0.11]Σ20.97, which is simplified to the ideal formula Al12(Te4+O3)5[(SO3)0.5(SO4)0.5](OH)24. Significant Te6+ substitution for Al3+ is observed in tomiolloite, verified by X‑ray photoelectron spectroscopy and crystal-structure analysis. The structure of tomiolloite was determined using synchrotron single-crystal X‑ray diffraction, showing that tomiolloite is hexagonal and crystallizes in the space-group P63/m, with the unit-cell parameters a = 13.3360(19) Å, c = 11.604(2) Å, V = 1787.3(6) Å3, and Z = 2. Tomiolloite has a unique microporous framework structure, which bears a slight similarity to that of zemannite, but it has a much larger cavity diameter (8.85 Å). The framework is built from edge-sharing Mφ6 octahedra (M = Al3+ and Te6+), Te4+O3 trigonal pyramids, and Te4+O4 disphenoids. Mφ6 octahedra edge-share to form crankshaft-shaped chains along c, with Te4+On polyhedra filling notches in the crankshafts and providing linkages between adjacent chains. The framework has an overall positive charge, which is balanced by the presence of both sulfite (SO32−) trigonal pyramids and sulfate (SO42−) tetrahedra in the channels. [ABSTRACT FROM AUTHOR]

The Daocaowan antimony (Sb) deposit is a newly discovered Sb deposit located outside the northeast Xikuangshan ore field. In the absence of geochemical data, the metallogenic mechanism of the Daocaowan Sb deposit and its relationship with the Xikuangshan ore field remains unclear. Using high-resolution LA-ICP-MS technique, this study quantitatively determined the in-situ S isotope values and trace element composition of stibnite from the Daocaowan Sb deposit in South China to investigate the source of ore-forming materials and genesis of this deposit. The trace element compositions of stibnite from the Daocaowan Sb deposit revealed the form of occurrence and substitution mechanism of trace elements in stibnite, providing new constraints for explaining the genesis of Sb deposits. The relatively smooth LA-ICP-MS profiles indicate that As, Cu, Hg, and Pb primarily occur as solid solutions in stibnite. Therefore, we speculate that the substitution 3Sb3+↔As3+ + 2Cu+ + Hg2+ + Pb2+ may be the reason for the enrichment of As, Cu, Hg, and Pb in stibnite. A comparison with the Xikuangshan Sb deposit reveals the metallogenic mechanism of the Daocaowan Sb deposit, and the relationship between the two. With the exception of higher content of Fe in Stibnite from the Daocaowan deposit as compared to the Xikuangshan deposit, other trace elements are similar between the two deposits. The results show that the Daocaowan and Xikuangshan Sb deposits may have the same source of ore-forming fluids. We propose that the ore-forming fluid flowed through the Xikuangshan Sb deposit along the F75 fault and dissolved pyrite in the wall rock. Subsequently this fluid containing a high concentration of Fe precipitated and mineralized at Daocaowan. Meanwhile, the S isotope value of the Daocaowan Sb deposit (+6.65 to +9.29‰) is consistent with that of the Xikuangshan, proving that the ore-forming materials of the two deposits are from the same source, probably the basement strata. We propose that the Daocaowan Sb deposit is part of the Xikuangshan ore field, indicating a great prospecting potential in the northeast of the Xikuangshan ore field. [ABSTRACT FROM AUTHOR]

Tellurite [Te(IV)] is a high-toxicity metalloid. In this study, a fungus with high Te(IV) resistance was isolated. Strain AB1 could efficiently reduce highly toxic Te(IV) to less toxic Te(0). The reduced products formed rodshaped biogenetic Te(0) nanoparticles (Bio-TeNPs) intracellularly. Further TEM-element mapping, FTIR, and XPS analysis showed that the extracted Bio- TeNPs ranged from 100 to 500 nm and consisted of Te(0), proteins, lipids, aromatic compounds, and carbohydrates. Moreover, Bio-TeNPs exhibited excellent antibacterial ability against Shigella dysenteriae, Escherichia coli, Enterobacter sakazakii, and Salmonella typhimurium according to inhibition zone tests. Further growth and live/dead staining experiments showed that E. coli and S. typhimurium were significantly inhibited by Bio-TeNPs, and cells were broken or shriveled after treatment with Bio-TeNPs based on SEM observation. Additionally, the antioxidant and cytotoxicity tests showed that the Bio-TeNPs exhibited excellent antioxidant capacity with no cytotoxicity. All these results suggested that strain AB1 showed great potential in bioremediation and Bio-TeNPs were excellent antibacterial nanomaterials with no cytotoxicity. [ABSTRACT FROM AUTHOR]

Antimony (Sb) is a priority pollutant in many countries and regions due to its chronic toxicity and potential carcinogenicity. Elevated concentrations of Sb in the environmental originating from mining and other anthropogenic sources are of particular global concern, so the prevention and control of the source of pollution and environment remediation are urgent. It is widely accepted that indigenous microbes play an important role in Sb speciation, mobility, bioavailability, and fate in the natural environment. Especially, antimony-oxidizing bacteria can promote the release of antimony from ore deposits to the wider environment. However, it can also oxidize the more toxic antimonite [Sb(III)] to the less-toxic antimonate [Sb(V)], which is considered as a potentially environmentally friendly and efficient remediation technology for Sb pollution. Therefore, understanding its biological oxidation mechanism has great practical significance to protect environment and human health. This paper reviews studies of the isolation, identification, diversity, Sb(III) resistance mechanisms, Sb(III) oxidation characteristics and mechanism and potential application of Sb-oxidizing bacteria. The aim is to provide a theoretical basis and reference for the diversity and metabolic mechanism of Sb-oxidizing bacteria, the prevention and control of Sb pollution sources, and the application of environment treatment for Sb pollution. [ABSTRACT FROM AUTHOR]

Major sources of pollution during the antimony (Sb) mining and processing are mining waste rock, smelting waste, tailings dam, and underground tunnel wastewater. The aim of the present study was to assess magnitude of pollution from Sb mine by taking four types of samples: soil in the mining waste rock zone, soil in the smelting zone, soil in tailings zone, and soil in underground tunnel wastewater zone. Sixty soil samples from the four zones were taken for experimental work, and the contents and morphological characteristics of the six potentially toxic elements (PTEs) such as Sb, As, Hg, Pb, Cd, and Zn in the soil samples were measured by using a hydride generation atomic fluorescence spectrometer (AFS-9700). The results show that the soil of the mine area is seriously polluted. The average contents of Sb, As, Hg, Pb, Cd, and Zn in the soil reach 1267.20 mg·kg−1, 94.44 mg·kg−1, 1.46 mg·kg−1, 184.19 mg·kg−1, 8.54 mg·kg−1, and 1054.11 mg·kg−1, respectively. There exists good correlation between the PTEs in the soil, with Sb strongly positively correlated with As, Hg, Pb, and Zn. The intensity of pollution is highest in the antimony-smelting zone, where the potential ecological risk index is over 15,000, followed by the tailings zone and mining waste rock zone, with the underground tunnel wastewater zone being the lowest. Using sequential chemical extraction, the elements are associated with the residual fraction, followed by organic-sulfide fraction, and smaller portions in the Fe-Mn oxide, carbonate, and exchangeable fractions. There are great differences in the speciation content of different elements in different sampling zones. The study implicates that Sb-smelting zone is the potential source of PTEs and maximum metals are associated with residual phase, out of which significant portion is associated with mobile fraction or phase. [ABSTRACT FROM AUTHOR]

Convolutional encoding and data decoding are fundamental processes in convolutional error correction. One of the most popular error correction methods in decoding is the Viterbi algorithm. It is extensively implemented in many digital communication applications. Its VLSI design challenges are about area, speed, power, complexity and configurability. In this research, we specifically propose a VLSI architecture for a configurable and low-complexity design of a hard-decision Viterbi decoding algorithm. The configurable and lowcomplexity design is achieved by designing a generic VLSI architecture, optimizing each processing element (PE) at the logical operation level and designing a conditional adapter. The proposed design can be configured for any predefined number of trace-backs, only by changing the trace-back parameter value. Its computational process only needs N + 2 clock cycles latency, with N is the number of trace-backs. Its configurability function has been proven for N = 8, N = 16, N = 32 and N = 64. Furthermore, the proposed design was synthesized and evaluated in Xilinx and Altera FPGA target boards for area consumption and speed performance. [ABSTRACT FROM AUTHOR]

Three new lipolytic genes were isolated from a forest soil metagenomic library by functional screening on tributyrin agar plates. The genes SBLip1, SBLip2 and SBLip5.1 respectively encode polypeptides of 445, 346 and 316 amino acids. Phylogenetic analyses revealed that SBLip2 and SBLip5.1 belong to bacterial esterase/lipase family IV, whereas SBLip1 shows similarity to class C β-lactamases and is thus related to esterase family VIII. The corresponding genes were overexpressed and their products purified by affinity chromatography for characterization. Analyses of substrate specificity with different p-nitrophenyl esters showed that all three enzymes have a preference for short-acyl-chain p-nitrophenyl esters, a feature of carboxylesterases as opposed to lipases. The β-lactamase activity of SBLip1, measured with the chromogenic substrate nitrocefin, was very low. The three esterases have the same optimal pH (pH 10) and remain active across a relatively broad pH range, displaying more than 60 % activity between pH 6 and 10. The temperature optima determined were 35 °C for SBLip1, 45 °C for SBLip2 and 50 °C for SBLip5.1. The three esterases displayed different levels of tolerance to salts, solvents and detergents, SBLip2 being overall more tolerant to high concentrations of solvent and SBLip5.1 less affected by detergents. [ABSTRACT FROM AUTHOR]

Geothermal energy has been a subject of great interest since the 1990s in the Upper Rhine Graben (URG), where the first European Enhanced Geothermal System (EGS) pilot site has been developed, in Soultz-sous-Forêts (SsF), France. Several studies have already been conducted on scales occurring at the reinjection side at the geothermal plants located in the URG. It has been observed that the composition of the scales changes as chemical treatment is applied to inhibit metal sulfate. The purpose of this study was to model the scaling phenomenon occurring in the surface pipes and the heat exchangers at the SsF geothermal plant. PhreeqC, a geochemical modelling software, was used to reproduce the scaling observations in the geothermal plant during exploitation. A suitable database was chosen based on the availability of chemical elements, minerals, and gas. A thermodynamic model and a kinetic model were proposed for modelling the scaling phenomenon. The thermodynamic model gave insight on possible minerals precipitated while the kinetic model, after modifying the initial rates equation, produced results that were close to the expected scale composition at the SsF geothermal plant. Additional laboratory studies on the kinetics of the scales are proposed to complement the current model. [ABSTRACT FROM AUTHOR]

The article draws attention to the problem of the presence of metals: germanium (Ge), tellurium (Te), thallium (Tl), and others (Cd, Ba, Co, Mn, Cr, Cu, Ni, Pb, Sr, and Zn) in selected waste of electrical and electronic equipment (WEEE). As a result of the growing demand for new technologies, the global consumption of TECs has also been increasing. Thus, the amount of metals in circulation, of which the impacts on the environment have not yet been fully understood, is constantly increasing. Due to the low content of these metals in WEEE, they are usually ignored during e-waste analyses. The main aim of this study was to determine the distribution of Ge, Te, and Tl (and other elements) in ground sieve fractions (1.0, 0.5, 0.2, and 0.1 mm) of selected electronic components (solar lamps, solar cell, LED TV screens, LCD screens, photoresistors, photodiodes, phototransistors) and to determine the possible tendency of the concentrations of these metals in fractions. This problem is particularly important because WEEE recycling processes (crushing, grinding, and even collection and transport operations) can lead to dispersion and migration of TCE pollutants into the environment. The quantitative composition of e-waste was identified and confirmed by ICP-MS, ICP-OES and SEM-EDS, and XRD analyses. It was found that Ge, Te, and Tl are concentrated in the finest fractions of ground e-waste, together with Cd and Cr, which may favor the migration of these pollutants in the form of dust during storage and processing of e-waste. [ABSTRACT FROM AUTHOR]

Metalloid tellurium is characterized as a chemical element belonging to the chalcogen group without known biological function. However, its compounds, especially the oxyanions, exert numerous negative effects on both prokaryotic and eukaryotic organisms. Recent evidence suggests that increasing environmental pollution with tellurium has a causal link to autoimmune, neurodegenerative and oncological diseases. In this review, we provide an overview about the current knowledge on the mechanisms of tellurium compounds' toxicity in bacteria and humans and we summarise the various ways organisms cope and detoxify these compounds. Over the last decades, several gene clusters conferring resistance to tellurium compounds have been identified in a variety of bacterial species and strains. These genetic determinants exhibit great genetic and functional diversity. Besides the existence of specific resistance mechanisms, tellurium and its toxic compounds interact with molecular systems, mediating general detoxification and mitigation of oxidative stress. We also discuss the similarity of tellurium and selenium biochemistry and the impact of their compounds on humans. [ABSTRACT FROM AUTHOR]

The optimization and validation of a methodology for determining and extracting inorganic ionic Te(VI) and Te(IV) forms in easily-leached fractions of soil by Ion Chromatography-Inductively Coupled Plasma-Mass Spectrometry (IC-ICP-MS) were studied. In this paper, the total concentration of Te, pH, and red-ox potential were determined. Ions were successfully separated in 4 min on a Hamilton PRPX100 column with 0.002 mg/kg and 0.004 mg/kg limits of detection for Te(VI) and Te(IV), respectively. Soil samples were collected from areas subjected to the influence of an electrowaste processing and sorting plant. Sequential chemical extraction of soils showed that tellurium was bound mainly with sulphides, organic matter, and silicates. Optimization of soil extraction allowed 20% average extraction efficiency to be obtained, using 100 mM citric acid as the extractant. In the tested soil samples, both tellurium species were present. In most cases, the soils contained a reduced Te form, or the concentrations of both species were similar. [ABSTRACT FROM AUTHOR]

Valentinite forms through the alteration of stibnite in sulphide deposits. Colloform sphalerite is a widespread mineral in low-temperature deposits, particularly those of the Mississippi-Valley type. We identified valentinite and colloform sphalerite in hydrothermal deposits occurring in the Baia Mare area. The Baia Mare metallogenic district of Neogene age occurs in the northwestern part of the Neogene volcanic chain within the Eastern Carpathians. The Neogene volcanism from Baia Mare area is related to the subduction processes of the East European plate under two microplates, Alcapa and Tisza-Dacia/Tisia, in the post-collisional compressive phase. We have identified valentinite in the Dealul Crucii and Baia Sprie deposits, associated with other epithermal minerals, in the absence of the stibnite. Valentinite is deposited in the final phase of the epithermal process after calcite and manganese-bearing calcite. Micro-Raman and microprobe determinations indicate the presence of valentinite. The formula of valentinite is close to stoichiometric Me2O3 and contains small amounts of tin as an antimony substituent. Colloform sphalerite was identified in the Baia Sprie ore deposit associated with minerals formed in the final epithermal phase. It was deposited on idiomorphic crystals of stibnite, which it corrodes. Its structure and an alternate banding, exhibited on the nano-/microscale, were identified by optical microscopy, SEM (scanning electron microscopy), and BSE (backscattered electron microscopy) imaging. These structures are typical for colloform sphalerite and suggest a genesis due to episodic precipitation. The spherical nano/micro-particles (nodules) are characteristic of the colloform sphalerite from Baia Sprie. Raman analysis indicates the presence of a colloform sphalerite with low iron content. The typical diffraction lines for sphalerite were identified in X-ray diffraction: 3.118 Å (111), 1.907 Å (220), 1.627 Å (311). Microprobe analysis certifies the presence of sphalerite with the stoichiometric formula close to ZnS. Iron content is low (0%–0.0613%), but Sb (0.7726%–2.6813%), Pb (0.56%–1.1718%), Bi (0%–0.1227%) are also present. The negative correlation between Zn and Sb suggests the simultaneous deposition from the same epithermal fluids. Valentinite and colloform sphalerite were formed at low temperatures (100–150 °C) at the end of the epithermal process. [ABSTRACT FROM AUTHOR]