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The advent of Neural-network Quantum States (NQS) has significantly advanced wave function ansatz research, sparking a resurgence in orbital space variational Monte Carlo (VMC) exploration. This work introduces three algorithmic enhancements to reduce computational demands of VMC optimization using NQS: an adaptive learning rate algorithm, constrained optimization, and block optimization. We evaluate the refined algorithm on complex multireference bond stretches of H2O and N2 within the cc-pVDZ basis set and calculate the ground-state energy of the strongly correlated chromium dimer (Cr2) in the Ahlrichs SV basis set. Our results achieve superior accuracy compared to coupled cluster theory at a relatively modest CPU cost. This work demonstrates how to enhance optimization efficiency and robustness using these strategies, opening a new path to optimize large-scale restricted Boltzmann machine-based NQS more effectively and marking a substantial advancement in NQS's practical quantum chemistry applications. [ABSTRACT FROM AUTHOR]

In the present study, we have investigated the effect of magnetic Cr doping on the transport properties of a sputtered Bi2Se3 thin film on the SrTiO3 (110) substrate. The high-resolution x-ray diffraction and Raman spectroscopy measurements revealed the growth of rhombohedral Bi2Se3 thin films. Further electronic and compositional analysis was done by x-ray photoemission spectroscopy and Rutherford backscattering spectroscopy, and the x-value was estimated to be 0.18 in the Bi2−xCrxSe3 thin film. The variation in the resistivity with temperature (2–300 K) revealed the metallic nature in undoped Bi2Se3 up to 30 K and upturn resistivity below 30 K. The Cr-doped Bi2Se3 resistivity data show a traditional semiconducting nature up to 25 K and take an abrupt upturn resistivity below 25 K. The resistivity behavior of both samples was explained by adopting a model that consists of the total resistance, a combination of bulk and surface resistance in parallel. The bulk bandgap value determined by this method is obtained to be 256 meV in an undoped Bi2Se3 thin film. Magnetoconductance data of the undoped thin film revealed a weak anti-localization (WAL) effect, while the Cr-doped thin film showed a weak localization (WL) effect at low temperatures (<50 K). At low magnetic field and low temperature, a competing nature of WAL and WL effects was prominent in the Cr-doped film. A drastic increase in the electrical resistance suggests that Cr doping can significantly modify the electrical properties of Bi2Se3 thin films, which could have potential applications in futuristic devices. [ABSTRACT FROM AUTHOR]

Density functional approximations to the exchange–correlation energy can often identify strongly correlated systems and estimate their energetics through energy-minimizing symmetry-breaking. In particular, the binding energy curve of the strongly correlated chromium dimer is described qualitatively by the local spin density approximation (LSDA) and almost quantitatively by the Perdew–Burke–Ernzerhof generalized gradient approximation (PBE-GGA), where the symmetry breaking is antiferromagnetic for both. Here, we show that a full Perdew–Zunger self-interaction-correction (SIC) to LSDA seems to go too far by creating an unphysical symmetry-broken state, with effectively zero magnetic moment but non-zero spin density on each atom, which lies ∼4 eV below the antiferromagnetic solution. A similar symmetry-breaking, observed in the atom, better corresponds to the 3d↑↑4s↑3d↓↓4s↓ configuration than to the standard 3d↑↑↑↑↑4s↑. For this new solution, the total energy of the dimer at its observed bond length is higher than that of the separated atoms. These results can be regarded as qualitative evidence that the SIC needs to be scaled down in many-electron regions. [ABSTRACT FROM AUTHOR]

Purpose: To compare the fit of 3D-printed titanium (Ti) and cobalt-chromium (Co-Cr) abutments with implants to computer numerical control (CNC)-milled, ready-made abutment-implant assemblies. Their clinical applicability was also evaluated by measuring removal torque values (RTVs) and percentage torque loss of abutment screws. Materials and Methods: A total of 138 abutments were included in the study: 92 abutments were fabricated with Ti and Co-Cr alloys using computerassisted design (CAD) through selective laser melting, and 46 ready-made abutments were prepared. The fit of interfaces between 90 abutments from the three groups (30 ready-made, 30 3D-printed Ti, and 30 3D-printed Co-Cr abutments) and implant assemblies was demonstrated by scanning electron microscopy (SEM) and confocal scanning laser microscopy (CSLM). After 30-Ncm torque tightening of Ti abutment screws twice within 10 minutes, the RTVs and percentage torque loss of screws of 48 abutments (16 ready-made, 16 3D-printed Ti, and 16 3D-printed Co-Cr) were evaluated after 10 minutes of thermocycling and cyclic loading. Results: The fits of 3D-printed Co-Cr abutments were not statistically different from those of ready-made abutments (P = .383), while the fit of 3D-printed Ti abutments was inadequate (P < .001). The RTVs of 3D-printed abutments after cyclic loading were significantly decreased compared with those of CNC-milled abutments (P < .001). Conclusion: The fit of interfaces between 3D-printed Co-Cr abutments and implants was adequate. The RTVs of 3D-printed Co-Cr abutments were not significantly different from those of CNC-milled abutments after 10 minutes of 30-Ncm torque tightening and thermocycling. [ABSTRACT FROM AUTHOR]

The aviation sector is believed to be responsible for considerable environmental damage attributed to emission of a large number and amount of pollutants. Airports are often surrounded by forest fragments and humid areas that attract birds of prey and hence may potentially serve as useful bioindicators. The aim of the present study was to examine genotoxic potential in raptors exposed to airport pollution using the micronucleus (MN) test and morphological changes as evidenced by bilateral symmetry. This investigation was conducted at Salgado Filho International Airport of Porto Alegre – RS as well as in private and zoological breeding grounds. The presence of metals was measured in the blood cells of the collected birds. Seventeen birds (Caracara (Polyborus) plancus) were used in this study 11 from exposed and 6 from non-exposed group. The nuclear alterations clearly indicate that organisms exposed to airport pollution exhibited a significantly higher frequency of genetic damage compared to non-exposed birds. Further, manganese and chromium were detected exclusively in the blood of the exposed group. In contrast, the analysis of bilateral symmetry did not detect any significant morphologic differences between the two groups. Therefore, data indicate that blood genotoxic stress occurs in birds of prey living in civil aviation areas as evidenced by MN frequency increase and presence of manganese and chromium. [ABSTRACT FROM AUTHOR]

In the study, the solid solubility limits of Cr3+ in the CaAl 12-x Cr x O 19 phase and leachability of any Cr6+ safety were investigated. Analytical tools and leaching experiments were used to investigate the Al3+ substitution in hibonite (CaAl 12 O 19) structure by Cr3+. The results showed that at Al:Cr=9:3, all the generated phases were chrome-hibonite (Ca 1.06 Cr 2.87 Al 9.07 O 18.99) and were also supported by the XPS and Cr6+ leaching experiments results. However, when proportion of Cr in system increases to Al:Cr=7:5, the primary phases are Ca 1.09 Cr 3.92 Al 8.01 O 18.98 and alumina-chrome solid solution (Al 0.77 Cr 1.22 O 3) along with a small amount of wuboraite solid-solution (CaAl 2±x Cr 2±x O 7 , a Cr3+ phase) and chrome-hauyne (Ca 4 Al 6 CrO 16 , a Cr6+ phase). At Al:Cr=7:5, distilled water and 0.1 mol/L HCl leach around 1.9 mg/L Cr6+, but HCl showed relatively faster leaching of Cr6+ than water and below the Chinese national standard of waste disposal of 3 mg/L. The maximum solid-solubility limit of Cr3+ in CaAl 12-x Cr x O 19 could be considered as x =3.9. [ABSTRACT FROM AUTHOR]

• Repeated-measure design in workers exposed to chromate was conducted. • Blood chromium was positively correlated with liver enzyme levels and bilirubin levels, suggesting that chromate exposure may cause liver injury. • Blood chromium was positively correlated with systemic inflammatory markers PLT and PLR, suggesting that chromate exposure may lead to increased systemic inflammation. • Systemic inflammatory markers PLT and PLR mediate the increase of liver enzymes and bilirubin induced by chromium exposure, with the mediating ratio ranging from 8.26% to 15.58%. Hexavalent chromium and its compounds are prevalent pollutants, especially in the work environment, pose a significant risk for multisystem toxicity and cancers. While it is known that chromium accumulation in the liver can cause damage, the dose-response relationship between blood chromium (Cr) and liver injury, as well as the possible potential toxic mechanisms involved, remains poorly understood. To address this, we conducted a follow-up study of 590 visits from 305 participants to investigate the associations of blood Cr with biomarkers for liver injury, including serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), and direct bilirubin (DBIL), and to evaluate the mediating effects of systemic inflammation. Platelet (PLT) and the platelet-to-lymphocyte ratio (PLR) were utilized as biomarkers of systemic inflammation. In the linear mixed-effects analyses, each 1-unit increase in blood Cr level was associated with estimated effect percentage increases of 0.82% (0.11%, 1.53%) in TBIL, 1.67% (0.06%, 3.28%) in DBIL, 0.73% (0.04%, 1.43%) in ALT and 2.08% (0.29%, 3.87%) in AST, respectively. Furthermore, PLT mediated 10.04%, 11.35%, and 10.77% increases in TBIL, DBIL, and ALT levels induced by chromate, respectively. In addition, PLR mediated 8.26% and 15.58% of the association between blood Cr and TBIL or ALT. These findings shed light on the mechanisms underlying blood Cr-induced liver injury, which is partly due to worsening systemic inflammation. [Display omitted] [ABSTRACT FROM AUTHOR]

Chromium-contaminated soil is a serious environmental problem that threatens human health and the environment. Electrokinetic technology is used as a promising solution to treat these soils, as it relies on applying an electric field to remove pollutants from the soil. In this study, four experiments were conducted, where experiments have shown that the use of wheat straw as an available, cheap, economical and efficient adsorbent material to prevent the occurrence of reverse osmosis. The results showed that the percentage of removal increased with the increase in the acidity of the medium, that is, as the pH decreased. This is due to an increase in the movement of pollutants as the soil particles become more positively charged, which enhances Attract negative heavy metal ions. This leads to increased movement of heavy metal ions into soil pores, making them more susceptible to transport under the influence of an electric field. The results proved that when using a disinfection solution with a pH of 2, it gave a higher result compared to pH 7 and 12, where the percentage of removal was 78.3%, 62.6 %, and 51.9% respectively. The dissolution of these metals can be enhanced by adding oxalic acid at a constant voltage gradient 1.2 v/cm and an initial concentration of 200 mg/kg. It was noted after the end of the experiment that the percentage of removal reached 81.9%, as the concentration of metals on the cathode side was higher than on the cathode side. The anode, and this is due to the migration of metals under the influence of electromigration to the cathode side, where the chromium concentration was 47 mg/kg at the cathode side, 27 mg/kg at the anode side. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

During the laser cladding process, complex composition distribution in the molten pool was caused from the Marangoni flow, which leading to one kind of defect termed as macrosegregation. Therefore, comprehensive understanding on the flow behaviors in the molten pool is particularly important for predicting and regulating macrosegregation. In this paper, a three-phase Eulerian model based on the volume averaging method is developed to investigate the effect of Marangoni coefficient variations on the flow and compositional distribution. The flow patterns were photographed and analyzed using a high-speed camera, and then the simulated and experimental results for chromium concentration distribution, size of the cladding layer, depth of the molten pool, and flow pattern were compared and found to be in agreement with each other; thus, the accuracy of the model was validated. Meanwhile, the effects of flow direction and intensity on the composition distribution are comprehensively studied. The results show that the flow direction extremely affects the flow path and evolution process of Cr-enriched melt in the molten pool. At the same time, the flow intensity will change the flow time of Cr-enriched melt in the molten pool and then affect the homogenization of composition distribution. [ABSTRACT FROM AUTHOR]

This study introduces a new biosorbent derived from Delonix regia bark-activated carbon to efficiently remove Chromium Cr(VI) metal ions from aqueous systems. The biosorbent was synthesized from the bark powder of the plant species and chemically activated with phosphoric acid. The biosorbent was characterized using FTIR, SEM, and BET to determine its functional properties and structural morphology. The batch adsorption experiments examined the optimal conditions for Cr(VI) metal ion adsorption, identifying that the highest removal efficiency occurred at pH levels of 2. The ideal adsorbent dosage was determined to be 2.5 g/L, with equilibrium achieved at a contact time of 60 min at the optimal temperature of about 303 K for a Cr(VI) metal ion concentration of 20 mg/L. Various isotherm models were applied to the adsorption equilibrium values, revealing that the adsorbent had a maximum removal capacity of approximately 224.8 mg/g for Cr(VI) metal ions. The adsorption process of Cr(VI) on the DAC biosorbent was best described by the Freundlich isotherm, indicating multilayer adsorption. The kinetic data fit well with the pseudo-second-order model. Thermodynamic parameters suggested that the adsorption process was spontaneous, exothermic, and feasible across different temperatures. Furthermore, the desorption studies showed that the DAC biosorbent can easily be rejuvenated and utilized several cycles with high adsorption capacity. These findings indicate that the developed adsorbent is environmentally friendly and effective for removing Cr(VI) from water systems. [ABSTRACT FROM AUTHOR]

Cr(VI) is a carcinogen with proven mutagenic and genotoxic effects. The effects of the depositional environment (e.g., paleoweathering, paleoclimate, and paleoredox condition) on Cr enrichment in non-ultramafic aquifer solids are unclear. In this study, we presented the sedimentary characteristics of a borehole from a typical non-ultramafic aquifer with high Cr groundwater in Jingbian, central Ordos Basin, China. Chromium was enriched in the K1h sandstone aquifer, especially at depths of 400–500 m, with the highest value of mass transport coefficient (τAl,Cr) up to 92.13% and τAl,Fe up to 33.5%. The provenance of aquifer Cr was predominantly intermediate and felsic igneous rocks with a mafic rock mixture. This mafic source was inferred from Cr-rich granodiorite and mafic/ultramafic rocks in the Yinshan (Daqingshan–Wulashan) Block, northern Ordos Basin. The Cr-rich aquifer in K1h was developed due to a moderate chemical index of alteration (CIA) (mean, 56.7) under relatively warm and humid paleoclimate, as evidenced by high CIA-temperature (CIA-Temp) (mean, 6.79 °C) and paleoclimatic index values (mean, 0.40). Fe–Mn redox cycling in the oxic to suboxic environments contributed to aquifer Cr accumulation. Using path analysis, we identified that paleoclimate created favorable weathering conditions and enrichment of Fe contributed to the formation of high-Cr aquifers. The study reveals the formation of positive Cr anomalies in non-ultramafic aquifers, which is the potential source of groundwater Cr, and highlights the effects of depositional factors on Cr accumulation during aquifer deposition or early diagenesis. It can provide new insights into the natural processes of high-Cr sediments occurring in non-ultramafic aquifers. [ABSTRACT FROM AUTHOR]

The Ni electrodeposition combined with multilayered structure film is a promising strategy in modern optical manufacturing, while less effort has been devoted to comprehending the electrochemical reaction process, which is essential for their practical applications. In view of this, the initial reduction dynamics and nucleation mechanisms of Ni electrodepositions on multilayer W/Si and Cr/C films were analyzed in this work, and the morphological, crystal, and mechanical characteristics of produced Ni electrodeposits were further determined and compared. The results show that the considerably irregular crystals accompanied by high tensile stress of 119.5 MPa were formed for the Ni electrodeposit on W/Si film, which were mainly attributed to the progressive nucleation process with more severe side reaction of hydrogen evolution. By contrast, the instantaneous nucleation mode with lower reduction resistance were revealed for the Ni electrodeposition on Cr/C film, which presented a comparatively fine–grained texture, less roughness, and smaller stress structure. To summarize, the more stable electrochemical reaction process and improved structure uniformity are obtained for the Ni electrodeposition on metal/C–based film, which offers a theoretical guidance for optimized fabrication of multilayer optical devices in extreme ultraviolet, x-ray, and neutron focusing fields. [ABSTRACT FROM AUTHOR]

Exfoliation of 2D non‐Van der Waals (non‐vdW) semiconductor nanoplates (NPs) from inorganic analogs presents many challenges ahead for further exploring of their advanced applications on account of the strong bonding energies. In this study, the exfoliation of ultrathin 2D non‐vdW chromium sulfide (2D Cr2S3) by means of a combined facile liquid‐phase exfoliation (LPE) method is successfully demonstrated. The morphology and structure of the 2D Cr2S3 material are systematically examined. Magnetic studies show an obvious temperature‐dependent uncompensated antiferromagnetic behavior of 2D Cr2S3. The material is further loaded on TiO2 nanorod arrays to form an S‐scheme heterojunction. Experimental measurements and density functional theory (DFT) calculations confirm that the formed TiO2@Cr2S3 S‐scheme heterojunction facilitates the separation and transmission of photo‐induced electron/hole pairs, resulting in a significantly enhanced photocatalytic activity in the visible region. [ABSTRACT FROM AUTHOR]

The tetracyanoborate anion [B(CN)4]− (TCB) was utilized as a building block for the synthesis of polynuclear chromium carbonyl compounds upon photolytic reaction with [Cr(CO)6]. Up to four κN-coordinated cyano groups of TCB can be involved in binding to chromium, giving mixtures of [B(CN)4−x{CN–Cr(CO)5}x]− (x = 1–4; 1–4) and [{Cr(CO)4(B(CN)4)}2]2− (5). The reaction of [B(CN)4]− with fac-[Cr(CO)3(MeCN)3] led to isolation of salts of the tetraanionic heterocubane cage [{Cr(CO)3(B(CN)4)}4]4−. [ABSTRACT FROM AUTHOR]

Arctium lappa, widely recognized as burdock, is a perennial plant that is employed in the realm of traditional Chinese medicine for a wide range of medicinal applications. The herb is rich in bioactive metabolites with therapeutic potential, encompassing polyphenolic antioxidants in its leaves, and flavonoids and fructo-oligosaccharides in its underground parts. Nutraceuticals originating from botanical sources such as Arctium lappa provide supplementary health advantages alongside their nutritional content and have demonstrated effectiveness in the prevention and management of specific ailments. The utilization of Arctium lappa root extract has exhibited encouraging outcomes in addressing hepatotoxicity induced by cadmium, lead, chromium, and acetaminophen, ameliorating liver damage and oxidative stress. Additionally, the root extract displays properties such as antidiabetic, hypolipidemic, aphrodisiac, anti-rheumatic, anti-Alzheimer, and various other pharmacological actions. [ABSTRACT FROM AUTHOR]

The tetracyanoborate anion [B(CN)4]− (TCB) was utilized as a building block for the synthesis of polynuclear chromium carbonyl compounds upon photolytic reaction with [Cr(CO)6]. Up to four κN-coordinated cyano groups of TCB can be involved in binding to chromium, giving mixtures of [B(CN)4−x{CN–Cr(CO)5}x]− (x = 1–4; 1–4) and [{Cr(CO)4(B(CN)4)}2]2− (5). The reaction of [B(CN)4]− with fac-[Cr(CO)3(MeCN)3] led to isolation of salts of the tetraanionic heterocubane cage [{Cr(CO)3(B(CN)4)}4]4−. [ABSTRACT FROM AUTHOR]

Hundreds of nanometer-thick metal layers are used as electrical conductors in various technologies and research fields. The intensity of the radiation transmitted by such devices is a small fraction and is often neglected. Here, it is shown that intense terahertz time-domain spectroscopy can probe the absolute electro-optical properties of a 100 nm thick gold sample in transmission geometry without the need to apply electrical contacts or handle wires. The terahertz conductivity of the metal film agrees with that obtained from standard contact measurements of the static component within the error bars. This experimental approach can help to quantify the electrical properties of opaque and conductive materials such as the composite electrodes used in photovoltaic or electrochemical applications, and in the quality control of metal films. [ABSTRACT FROM AUTHOR]

A dual cobalt and chromium photoredox-catalyzed allylation of aldehydes with allenes through a photo metal-hydride atom transfer (MHAT) process has been developed to yield homoallylic alcohols with exceptional diastereoselective control. This sustainable and efficient method holds significant promise for applications in the synthesis of valuable organic compounds. [ABSTRACT FROM AUTHOR]

MAX phases are intriguing materials due to their unique properties. However, each of these materials possesses its own weaknesses when subjected to service conditions. For example, while one MAX phase exhibits self-lubricating feature, it may not perform well under high load conditions. This study investigates the impact of adding chromium to Ti 2 AlC on microstructure and mechanical properties. Samples are prepared through ball-milling and spark plasma sintering (SPS), then analyzed using various techniques. The presence of different phases, including MAX phases (Ti 2 AlC and Cr 2 AlC), carbides (TiC and Cr 7 C 3), and low amounts of oxides, is identified. Hardness, fractography, and wear characteristics are assessed through indentation and sliding tests. The study correlates the wear rate of each sample with experimental (H/E) and theoretical indicators (B/G), showing the production of composites with improved properties suitable for diverse applications. [ABSTRACT FROM AUTHOR]

Low‐valent chromium catalysts are cheap and less toxic compared to other transition metal catalysts. Here in, we reported a ligand‐free chromium(III)‐catalyzed manganese reductive cross‐coupling of unactivated alkyl electrophiles, such as alkyl sulfonates and alkyl chlorides, with trisulfide dioxides as thiolation agents to form carbon−sulfur bonds. The powerful method featured ample substrate scope and wide functional group tolerance, constructing a large number of unsymmetrical disulfides under simple conditions. [ABSTRACT FROM AUTHOR]

This study describes an unprecedented chromium‐catalyzed asymmetric Reformatsky reaction, enabling the synthesis of chiral β‐hydroxy carbonyl compounds from α‐chlorinated or α‐brominated esters and amides. By employing a chiral chromium/diarylamine bis(oxazoline) catalyst, we achieved relatively broad functional group tolerance. Distinct from known reports, the protocol operates under both classical and photoredox conditions, facilitated by the in situ formation of a nucleophilic chiral chromium intermediate through a radical‐polar crossover mechanism. Preliminary mechanistic insights, supported by DFT calculations, identify the nucleophilic aldehyde addition as the key stereo‐determining step. This approach not only overcomes the limitations of existing Reformatsky reactions but also provides a versatile strategy for accessing complex chiral molecules. [ABSTRACT FROM AUTHOR]

Although dearomative functionalizations enable the direct conversion of flat aromatics into precious three‐dimensional architectures, the case for simple arenes remains largely underdeveloped owing to the high aromatic stabilization energy. We herein report a dearomative sequential addition of two nucleophiles to arene π‐bonds through umpolung of chromium–arene complexes. This mode enables divergent dearomative carbonylation reactions of benzene derivatives by tolerating various nucleophiles in combination with alcohols or amines under CO‐gas‐free conditions, thus providing modular access to functionalized esters or amides. The tunable synthesis of 1,3‐ or 1,4‐cyclohexadienes as well as the construction of carbon quaternary centers further highlight the versatility of this dearomatization. Diverse late‐stage modifications and derivatizations towards synthetically challenging and bioactive molecules reveal the synthetic utility. A possible mechanism was proposed based on control experiments and intermediate tracking. [ABSTRACT FROM AUTHOR]

Two-dimensional materials possessing intrinsic multiferroic properties have long been sought to harness the magnetoelectric coupling in nanoelectronic devices. Here, we report the achievement of robust type I multiferroic order in single-layer chromium trihalides by decorating transition metal atoms. The out-of-plane ferroelectric polarization exhibits strong atomic selectivity, where 12 of 84 single-layer transition metal-based multiferroic materials possess out-of-plane ferroelectric or antiferroelectric polarization. Group theory reveals that this phenomenon is strongly dependent on p–d coupling and crystal field splitting. Cu decoration enhances the intrinsic ferromagnetism of trihalides and increases the ferromagnetic transition temperature. Moreover, both ferroelectric and antiferroelectric phases are obtained, providing opportunities for electrical control of magnetism and energy storage and conversion applications. Furthermore, the transport properties of Cu(CrBr3)2 devices are calculated based on the non-equilibrium Green's function, and the results demonstrate outstanding spin-filtering properties and a low-bias negative differential resistance (NDR) effect for low power consumption. [ABSTRACT FROM AUTHOR]

Biochar (BC) has been paid responsiveness during current decades. The present study, BC with chromium, aimed to investigate the research status and future developments. To do so, from the Scopus database, 855 documents regarding BC with chromium were acquired during the study period from 2011 to 2022 and a bibliometric analysis was implemented. Chemosphere was the topmost journal in which most of the papers were published. China is categorized first followed by India and the USA in the publications. With 42 articles, Xinde Cao from China is the topmost author in this research area. China established collaboration with South Korea and the USA. Most influencing authors, journals, papers, and organizations were deliberated in addition to the investigation of keywords. Furthermore, the impact of chromium on soil, plants, and human beings was elaborated followed by the de-pollution mechanism (surface adsorption/reduction, ion exchange method, electrochemical interaction, surface complexation). Its removal efficiency was associated with the effect of adsorbent, pyrolysis temperature, dose, surface area, and pH. The renewal of sorbed BC was elaborated. Current research status and present problems of its elimination in the polluted environment were added. This contributes a lot of ideas to the contemporary research community who are employed in the field of chromium elimination in contaminated environments. [ABSTRACT FROM AUTHOR]

N-containing biochar from oatmeal was produced by co-pyrolysis of hydrochar, ZnCl2, and FeCl3, showing well-developed pores with surface areas of 2744 m2/g and N species of 5.4 at.%. The as-formed biochar was used for Cr(VI) removal via batch adsorption, and the different parameters, i.e., initial pH, contact time, and concentration on efficiency, were evaluated. Adsorptive results indicated that Cr(VI) removal is largely affected by surface areas and functional groups of biochar under optimum pH value of two, following by pseudo-second-order and Langmuir model. The maximum capacity for Cr(VI) is up to 139 mg/g from synergistic effect of adsorption and reduction mechanism, much higher than that of analogous in the absence of FeCl3 with capacity of 113 mg/g and commercial activated carbons of 61 mg/g. N-containing biochar also had superior recyclability with capacity still up to 67.5 mg/g even after ten times recycling. The inexpensive feedstock and high removal performance made the present biochar be a promising candidate for Cr(VI) removal from wastewater. [ABSTRACT FROM AUTHOR]

The origin of elemental chromium for the archaeological weapons from the pits of Qin terracotta warriors in China has been highly controversial. Although previous studies have highlighted that the chromium on the surface of weapon originated from the contamination of surrounding lacquer, the exact origin of chromium in the lacquer remains unclear. In this work, the measurement by inductively coupled plasma-mass spectrometer (ICP-MS) firstly confirmed that the elemental chromium was indeed contained in the archaeological Qin original lacquer. Nevertheless, the amount of elemental chromium in the Qin lacquer was as low as 0.0759 μg/mg, disclosing that it was impossible to artificially add extra refined chromium-containing substance to the lacquer in the preparation of the terracotta warriors. The soil from the archaeological site of Qin lacquer was found to have a chromium amount of 0.0660 μg/mg by ICP-MS. After the hygrothermal and soil-buried aging cycles for the lab-prepared lacquer, the surface and depth elemental analyses by time of flight-secondary ion mass spectrometer (TOF–SIMS) showed a gradient distribution of elemental chromium from the surface to interior of aged lacquer, indicating the migration and enrichment behavior of elemental chromium from the burial soil towards the lacquer. To explore the migration mechanism of elemental chromium, fluorescence imaging technique was employed in combination with Fourier transform infrared spectrometry (FT-IR) and X-ray photoelectron spectroscopy (XPS) characterizations. The results revealed that catechol-containing fragments were formed during hygrothermal and soil-buried aging of lacquer and consequently coordinated with chromium ions, inducing the migration of elemental chromium towards the lacquer. [ABSTRACT FROM AUTHOR]

The presence of heavy metals in wastewater is an environmental concern and the current treatment procedures are very expensive so it is necessary to find effective and inexpensive biosorbents. In this study, Fucus vesiculosus was used as a biosorbent for the biosorption of Cr(III) ions from the aqueous solutions. Biosorption parameters, such as pH, adsorbent dose, contact time, and initial concentrations of Cr(III) had the most impact on the sorption process. The required pH value for sorption was 5, the biosorbent dose was 4.0 g/L, the contact time was seen to occur after 90 min, and the Cr(III) removal decreased from 98.9 to 92%. The maximum biosorption capacity of chromium was 14.12 mg/g. FTIR analysis of Fucus vesiculosus biomass before the sorption process contains carboxyl, amino, hydroxyl, alkyne, and carbonyl groups, and according to the analysis after the sorption process, it was found that Cr(III) metal ions were incorporated within the sorbent during the interaction with (=C–H) active functional groups. The biosorption data were found to be perfectly suited by Langmuir equilibrium isotherm model. According to the results of this study, Fucus vesiculosus is an effective biosorbent for the removal of Cr(III) from aqueous solutions. [ABSTRACT FROM AUTHOR]

Occupational dermatitis (OD) is an inflammatory skin disease stemming from exposure to specific substances within a work setting. As the second most prevalent occupational health concern in 2020, affecting 1.8 per 10,000 workers, OD poses a significant challenge to workforce well‐being and imposes a substantial economic burden through lost wages, decreased productivity, and increased healthcare spending. Dermatologists emerge as pivotal figures in recognizing risk factors and delivering essential care to individuals with OD. This review focuses on chemical hazards and toxic substances regulated by the Occupational Safety and Health Administration across general industry, maritime, and construction sectors. It explores the background of each hazard, pathophysiology to dermatitis, and human cases reported between 2017 and 2023 for formaldehyde, chromium, vinyl chloride, and cadmium. [ABSTRACT FROM AUTHOR]

The post‐tanning process of leather making involves the of large quantities of auxiliary chemicals to enhance the functionalities of the leather. Hence, developing multifunctional polymers are essential to reduce the pollution load and enhance sustainability. Herein, we report the synthesis of multifunctional retanning and fatliquoring agent using a hydroxyethyl methacrylate (HEMA) monomer by modifying the hydroxyl group to carboxyl and long‐chain hydrocarbon along with quaternary ammonium monomer. The resulting polymer has been subsequently used in the tanning and post‐tanning process. The influence of the carboxyl group increases the metal uptake of the aluminum (twofold) and zirconium (1.5‐fold) tanning agent, and hydrothermal stability of the polymer‐treated leathers is 74 and 81°C for aluminum and zirconium tanning, respectively. The experimental leather showed uniform pore size distribution and better organoleptic characteristics than the control. Introducing the quaternary ammonium group in the polymer increased dye exhaustion in the experimental process up to 97%. The anti‐bacterial studies show the polymer is effective against gram‐positive species due to electrostatic interaction. The biochemical analysis of the experiment process shows higher biodegradability (0.62). Thus, the present study opens a new avenue for a sustainable replacement for conventional post‐tanning chemicals. [ABSTRACT FROM AUTHOR]

The accumulation of chromium in renal tissues promotes the generation of reactive oxygen species (ROS), leading to oxidative stress, genomic and cellular harm, and ultimately necrotic and apoptotic cell death induced by free radicals. Hence, the utilization of antioxidant phytochemicals becomes crucial for cellular defense against oxidative damage. This study endeavors to explore the potential protective effects of an aqueous avocado seed extract (ASE) on rabbit kidneys exposed to chromium‐induced damage. Fifteen adult rabbits were distributed into three groups: Group 1 was kept as the control. The second and third groups received a daily dose of K2Cr2O7 (5 mg/kg) intraperitoneally for 2 weeks. While the third group was given an oral dose of ASE (400 mg/kg). In rabbits administered with Cr (VI), kidney homogenates showed a marked increase in Malondialdehyde (MDA) (69.3 ± 4.1 nmol/g) along with a decrease in glutathione (59 ± 5.8 nmol/mg) content and the activity superoxide dismutase (SOD) (0.5 ± 0.05 U/mg protein), glutathione peroxidase (GPx) (16.7 ± 1.1 μmol/mg protein), and catalase (CAT) (73.8 ± 3.9 U/g protein) compared to the levels in control group. Also, the gene expression data for the enzymes SOD, GPx, and CAT dropped dramatically in kidney tissue following Cr (VI) injection. Additionally, Bowman's capsule and glomerulus showed degenerative alterations in the kidney's histopathology and immunohistochemistry. ASE treatment when administered along with Cr (VI) enhanced the activity and gene expression of antioxidant enzymes and improved histopathological conditions. The findings of this study unequivocally show that avocado seed extract, which is rich in phenolic derivatives, is a potent nephroprotective agent that inhibits nephrotoxicity induced by Cr (VI) in rabbits. [ABSTRACT FROM AUTHOR]

Improvement of wear, corrosion, and heat-resistant properties of coatings to expand the operational capabilities of metals and alloys is an urgent problem for modern enterprises. Diffusion titanium, chromium, and aluminum-based coatings are widely used to solve this challenge. The article aims to obtain the corrosion-electrochemical properties and increase the microhardness of the obtained coatings compared with the initial Ti-6Al-4V alloy. For this purpose, corrosion resistance, massometric tests, and microstructural analysis were applied, considering various aggressive environments (acids, sodium carbonate, and hydrogen peroxide) at different concentrations, treatment temperatures, and saturation times. As a result, corrosion rates, polarization curves, and X-ray microstructures of the uncoated and coated Ti-6Al-4V titanium alloy samples were obtained. Histograms of corrosion inhibition ratio for the chromium–aluminum coatings in various environments were discussed. Overall, the microhardness of the obtained coatings was increased 2.3 times compared with the initial Ti-6Al-4V alloy. The corrosion-resistant chromaluminizing alloy in aqueous solutions of organic acids and hydrogen peroxide was recommended for practical application in conditions of exposure to titanium products. [ABSTRACT FROM AUTHOR]

The study investigates the practical application of cyclic wet/dry corrosion tests in simulated industrial atmospheres to assess the impact of chromium (Cr) on the protective properties of vanadium micro‐alloyed weathering steels. Two types of steels were examined: a V‐N steel and a V‐N‐Cr micro‐alloyed weathering steel. These steels were subjected to corrosion tests with 0.01 mol/L NaHSO3 at a pH range of 4.4–4.8 for varying durations. The findings indicate that the inclusion of Cr in the composition of vanadium micro‐alloyed weathering steel enhances corrosion resistance and leads to the accumulation of Cr in the inner rust layer. Furthermore, the distribution of corrosion‐resistant elements (Cr, Ni, Cu, P, and Mo) in V‐N and V‐N‐Cr steels is analyzed. The rust layer was observed to exhibit stratification in the corrosive environment, with the outer layers being dense and uniform, while the inner layers were porous and exhibited poor adhesion to the matrix. The study also delves into the anticorrosion mechanism of vanadium weathering steel using techniques such as X‐ray diffractometer, electron probe microanalysis, and potential‐phase diagram. [ABSTRACT FROM AUTHOR]

The present study aimed to assess metal/heavy metal intake by the population via food environment of the Uddanam region, a hotspot for chronic kidney disease of uncertain aetiology (CKDu) in India. The food samples included rice/paddy, marine/freshwater fish, green gram/black gram (whole), and green leafy vegetables (GLVs, i.e. amaranth/spinach). These were analysed for metal/heavy metal (chromium, nickel, copper, arsenic, lead, magnesium, calcium, aluminium, manganese, iron, zinc, barium, cadmium, mercury, and uranium) content using standard procedures. The total heavy metal intake was calculated as a sum of the intake from each food source. The daily dietary intake was compared to safe intake levels (from the Institute of Medicine of the National Academies and National Institute of Nutrition). The intake was higher than safe levels for lead, chromium, and manganese. It is advisable to reduce heavy metal exposure by adopting agricultural practices and public health interventions in terms of diet. [ABSTRACT FROM AUTHOR]

Ni3Al and Cr-Ni3Al films were deposited on Inconel-718 using the DC magnetron sputtering at a substrate temperature of 400 °C. The evolution of phase, microstructure, surface topography, and mechanical properties of the deposited films have been characterized using XRD, FESEM, AFM, and nanoindentation, respectively. The results of nanoindentation showed that the hardness, modulus, and adhesive strength of the coatings increased with increase in Cr concentration in the host Ni3Al matrix. The maximum hardness and modulus of 10.62 and 150.42 GPa respectively are shown by 5.7 at% of Cr-Ni3Al films. The cyclic oxidation tests were performed at elevated temperatures of 900 °C, 1000 °C, and 1100 °C in the open-air environment to study the actual oxidation attack. The results of the test showed that the rate of oxidation in Ni3Al and Cr-Ni3Al films was low as compared to the uncoated substrate. Ni3Al film doped with 5.7 at% of Cr-Ni3Al has resulted in providing better protection to the substrate against oxidation attacks. The surface morphology and elemental composition of the oxidized samples were investigated using FESEM and EDS to elucidate the surface scale analysis and mechanism of oxidation due to the formation of different oxide layers. [ABSTRACT FROM AUTHOR]

The present study aims to remove chromium (Cr) from a synthetic solution using Ziziphus jujube seed (ZJS)‐activated biochar (ZJSAB) as an adsorbent. Physicochemical characterization was carried out to understand the properties of ZJSAB samples. Adsorption characteristics of ZJSAB were determined using batch experiments for various temperatures, pH, dosage, concentration, and duration. The study reveals ZJSAB has 93 % efficiency in the removal of Cr for an initial concentration of 60 mg L−1 at 30 °C and 2 pH with 0.6 g L−1 dosage and 120 min duration. Freundlich isotherm and pseudo‐second‐order models were best fit with maximum removal efficiency for ZJSAB. When 0.3 N hydrochloric acid was introduced to a desorption study, Cr desorption was 93.47 %. The study reveals that activated biochar from ZJS was efficient for Cr removal from aqueous solutions. [ABSTRACT FROM AUTHOR]

In recent years, there has been an increase in environmental catastrophes involving mining dam failures. This study assessed the potential risks of iron ore tailings in riparian soils to human health after the worst dam collapses recorded in Brazil: from Córrego do Feijão Mine-CFM and Fundão. Chemical monitoring data from the three-year time interval since the collapses were used to estimate human risk indexes for trace elements such as arsenic, cadmium, chromium, mercury, nickel, lead, and zinc. In both case studies, the adult group indicated a propensity for the development of non-carcinogenic diseases through ingestion, inhalation and dermal pathways for all contaminated areas. Overall, children showed an exacerbated sensitivity to possible cancerous and non-cancerous effects, especially in the areas surrounding the dams and in Barra Longa, São José do Goiabal, Córrego Novo, Veneza, Periquito, Governador Valadares, Tumiritinga, Conselheiro Pena, Honório Fraga and Linhares (from the Fundão dam) and in all study areas from the CFM dam. These assessments demonstrate that in regions with mining activities, the cumulative effects of trace elements over time are harmful and expected. Therefore, there is a need for greater supervision by competent government bodies of conservation practices that enable environmental recovery or mitigation of their impacts, ensuring appropriate health and well-being conditions for local residents and workers. [ABSTRACT FROM AUTHOR]

Objective: This research investigated the effect of administering chromium (Cr) and meloxicam (MEL) on growth performance, cortisol and blood metabolite, and behaviors in young, regrouped heifers. Methods: Fifty Holstein dairy heifers (body weight [BW] 198±32.7 kg and 6.5±0.82 months of age) were randomly assigned to non-regrouped group or four regrouped groups. Non-regrouped animals were held in the same pen throughout the entire experimental period (NL: non-regrouping and administration of lactose monohydrate [LM; placebo]). For regrouping groups, two or three heifers maintained in four different pens for 2 weeks were regrouped into a new pen and assigned to one of four groups: regrouping and LM administration (RL); regrouping and Cr administration (RC); regrouping and MEL administration (RM), and regrouping and Cr and MEL administration (RCM). LM (1 mg/kg BW), Cr (0.5 mg Cr picolinate/kg dry matter intake), and MEL (1 mg/kg BW) were orally administered immediately before regrouping. Blood was collected before regrouping (0 h) and at 3, 9, and 24 h and 7 and 14 d thereafter. Behaviors were recorded for 7 consecutive days after regrouping. Results: Average daily gain was lower (p<0.05) in RL than NL heifers, but was higher (p<0.05) in RM, RC, and RCM than RL heifers. RL heifers had higher (p<0.05) cortisol than NL heifers on d 1 after regrouping. The cortisol concentrations in RC, RM, and RCM groups were lower (p<0.05) than in RL treatment 1 d after regrouping. Displacement behavior was greater (p<0.05) in RL group than all other groups at 2, 3, and 6 d after regrouping. Conclusion: Regrouping caused temporal stress, reduced growth performance, and increased displacement behavior in heifers. Administering Cr and MEL recovered the retarded growth rate and reduced displacement behavior, thereby alleviating regrouping stress. [ABSTRACT FROM AUTHOR]

The content of chromium (Cr) affects the mechanical and wear resistance of steel. Hence, the determination of Cr in steel is of great significance to determine the quality. In this study, a new method based on laser-induced breakdown spectroscopy (LIBS) combined with extreme random tree (ERT) is reported to determine Cr in steel. First, the Cr I 425.43 nm line was selected for univariate quantitative analysis. Next, multivariate analysis of Cr was performed using partial least squares regression (PLSR), random forest (RF), and ERT. The abilities of the models for the determination were validated by the fitting coefficient (R2), root mean square error of calibration (RMSEC), root mean square error of prediction (RMSEP), and average relative error (ARE). The R2, RMSEC, RMSEP, and ARE values of ERT were 0.9984, 0.0274 wt.%, 0.0299 wt.%, and 2.43%, respectively. Compared with the univariate model, PLSR, and RF models, the R2 of ERT increased by 0.1317, 0.0306, and 0.013, respectively; RMSEC decreased by 0.0987, 0.0955, and 0.0174 wt.%; RMSEP decreased by 0.1463, 0.0876, and 0.002 wt.%; and ARE decreased by 17.88%, 16.98%, and 5.95%, respectively. The results show that combining LIBS with the ERT model for multivariate analysis improves the elemental analysis of steel. [ABSTRACT FROM AUTHOR]

Transparent spinel with high real in-line transmittance (RIT up to 79%) was prepared from commercial spinel powder by capsule-free hot isostatic pressing (HIP). Optimal pre-sintering conditions were found in order to enhance the RIT values and doping with Cr3+ (0.01–0.04 at%) and Tb3+ (0.05–0.125 at%) secured photoluminescence. The incorporation of the dopants in tested range does not noticeably reduced the RIT. The Cr3+-doped MgAl 2 O 4 shows efficient narrow red emission at about 685 nm (R-line) due to the 2E g →4A 2g transition of Cr3+ ions located in octahedral sites of D 3d local symmetry with a strong crystal field. The Tb3+-doped MgAl 2 O 4 ceramics have shown emissions from blue to red spectral range (5D 4 →7F 3–6 transitions), with prominent green emission centered at 545 nm. The maximal emission intensity was achieved at 0.075 at% of Tb3+, Further increase of Tb3+ content led to the concentration quenching caused by Tb3+ ions segregation at the grain boundaries. [ABSTRACT FROM AUTHOR]

Fish is among the most affordable and readily available protein sources for communities residing near water bodies. However, the recent pollution status of aquatic ecosystems has rendered fish consumption risky for human health. The study evaluated metal levels in the liver, gill, and muscle tissues of Redbreast tilapia (Coptodon rendalli) from Inanda and Nagle dams in the uMgeni River system. Metals, Al, Sb, Cd, Cr, Fe, Mn, Mo, Pb, and Zn were analysed using ICP-OES. Fish size showed no significant difference between the two dams (p > 0.05) whereas a descending trend liver > gill > muscle was observed for most metal levels at both dams. Moreover, there was a clear separation for metal levels in the liver, gill, and muscle between the two dams (p < 0.001) and a similar trend was observed for organs in each dam (p < 0.001). No relationship was observed between fish length and metal levels and no definite trend was observed for inter-metal relationships. Antimony, Cr, and Pb showed THQs greater than 1 at both dams which suggests health risks for consumers. Molybdenum has also shown a concerning THQs with some individuals exhibiting values ranging from 0.5 – 0.9. These findings suggest that consuming C. rendalli from the Inanda and Nagle dams could result in adverse health effects from Sb, Cr and Pb. [ABSTRACT FROM AUTHOR]

Hexavalent chromium (Cr(VI) contamination in water and wastewater can be treated by reduction of Cr (VI) to Cr(III) with reductants. In this study, the practicality of using FeOx crystals obtained from wastewater was evaluated by studying their reaction with Cr(VI). Cr(VI) was completely removed within 1 to 8 hours of reaction with FeOx, depending on the initial concentration up to 1.9 mM tested. After complete removal of Cr(VI) by FeOx, 22%-38% of the original concentration of Cr(VI) was converted to Cr(III) in the solution, indicating the remaining 62%-78% of the Cr(VI) was associated with the FeOx surface. Cr(VI) was removed by FeOx via reduction to Cr(III) and adsorption/precipitation on the FeOx surface. At pH 3, Cr(VI) was completely removed by FeOx within 20 minutes. Around 20% of the initially added Cr(VI) remained in the solution as Cr(III), while approximately 80% was removed from the solution. At pH 7, roughly 30% of the Cr(VI) was reduced to Cr(III) and the remaining 40% appeared to be in the solid phase after 2-hour reaction. At pH 10, approximately 40% of the Cr(VI) was removed, but Cr(III) was not observed in the solution. The Cr(VI) removal by FeOx is mainly achieved by the reduction of Cr(VI) to Cr(III) under acidic to neutral conditions, and by the adsorption of Cr(VI) onto the solid phase under alkaline conditions. The reduction of Cr(VI) occurred mainly through the reaction with ferrous iron of FeOx, which was enhanced by oxalate of FeOx, forming a soluble Fe(III)-oxalate complex with Fe(III) and reducing the passivation of the FeOx surface. Our study indicates that FeOx is effective at removing Cr(VI) at various concentrations and pH levels. [ABSTRACT FROM AUTHOR]