Genome-wide Characterization of cis-acting Elements in the Promoters of Key Carotenoid Pathway Genes from the Main Species of Genus Citrus

Carotenoids are indispensable for both human health and plant survival.Citrus,is one of the fruit crops richest in carotenoid compounds,with approximately 115 kinds of carotenoids;tremendous diversity in carotenoids composition and concentration exists among various species,showing different colors from nearly white to crimson.The carotenoid biosynthetic pathway and the key carotenogenic genes have been identified in citrus;however,the underlying regulatory mechanisms remain unclear.In this study,among the main species of genus Citrus(primitive,wild,and cultivated),we detected carotenoids in flavedo using High-Performance Liquid Chromatography,and analyzed variations in cis-acting elements in the promoters of key carotenoid pathway genes.Intriguingly,both carotenoid composition and content were generally increased during the evolution of citrus,and the corresponding variations in the promoters were identified,including the gain or loss of critical environmental stress-responsive elements and hormone-responsive elements,which are closely associated with carotenoid enhancement.In addition,pummelo has the most heat-responsive elements,but the Mangshan mandarin does not have this element in the promoters of PSY,which is highly related to their geographical origin and indicate that temperature is a critical environmental signal influencing carotenoid accumulation.Moreover,the abscisic acid-responsive motif was rich in almost all the seven species,but the ethylene-responsive motif was deficient,which demystified the unique phytohormone regulation mechanism of carotenoid accumulation in citrus.Overall,our study provides new insights into the molecular regulatory mechanism of carotenoid enhancement in the evolution of citrus,which can facilitate breeding and cultivation efforts to improve the nutritional quality and esthetic value in citrus and hopefully other fruit crops.

Genomic Analysis of MicroRNA Promoters and Their Cis-Acting Elements in Soybean

MicroRNAs （miRNAs） are derived from distinct loci in the genome and play crucial roles in RNA-mediated gene silencing mechanisms that regulate cellular processes during development and stress responses of plants. The miRNAs are approximately 21 nucleotides long and code for the complementary strand to a larger genic mRNA. They are often found within the complementary primary transcript （pri-miRNAs）. In the past few years, a growing number of soybean miRNAs have been discovered, however, little is known about the transcriptional regulation of these miRNAs. In this study, promoters and cis-acting elements of soybean miRNAs were analyzed using the genomic data for the first time. A total of 82 miRNAs were located among 122 loci in genome, some were present as double or multiple copies. Five clusters that included ten miRNAs were found in genome, and only one cluster share the same promoter. A total of 191 promoters from 122 loci of the soybean miRNA sequences were found and further analyzed. The results indicated that the conserved soybean miRNA genes had a greater proportion of promoters than that of non-conserved ones, and the distribution of the transcript start sites （TSSs） and TATA-boxes found had different motif styles between conserved and non-conserved miRNA genes. Furthermore, the cis-acting elements 5＇ of the TSSs were analyzed to obtain potential function and spatiotemporal expression pattern of miRNAs. The data obtained here may lead to the identification of specific sequences upstream of pre-miRNAs and the functional annotation of miRNAs in soybean.

Interactions between the nuclear matrix proteins and the 5'-flanking cis-acting elements of the human ε-globin gene

An erythroid-specific nuclear matrix protein (termed ε-NMP_k) in K562 cells, which can specifically bind to the positive stage-specific regulatory element (ε-PRE Ⅱ, -446—-419 bp) upstream of the human ε-globin gene, has been identified by using gel mobility shift assay.Meanwhile, Southwestern blotting assay showed that the nuclear matrix protein ε-NMP_k in K562,cells may be composed of two polypeptides ( ～ 40 ku). In addition, it is observed in the gel mobility shift assay that the nuclear matrix proteins from K562, HEL and Raji cells can bind to the silencer DNA ( - 392— -177 bp) in the 5’-flanking sequence of human ε-globin gene respectively. However, the shift band K detected in K562 cells is different from shift band H/R in HEL and Raji cells, suggesting that a common nuclear matrix protein may exist in HEL and Raji cells. Results show that the nuclear matrix protein may play an important role in the regulation of the human ε-globin gene expression.

Identification of the 2-tridecanone cis-acting element in the promoter of cytochrome P450 CYP6B7 in Helicoverpa armigera

The expression level of cytochrome P450 genes in insects can be induced by plant allelochemicals,which is important for insects to adapt to host plants.Cytochrome P450CYP6B 7has been reported to be involved in pyethroid insecticide resistance in Heli- coverpa armigera,and its transcription level was induced by some inducers.Currently,the regulatory mechanism of the induced expression of CYP6B7remains unknown,although it is very important for understanding the detoxification mechanism to allelochemicals in host plants.The objective of the present study was to investigate the eis-acting ele- ment in the promoter of CYP6B7 mediating the inducible up-regulation of CYP6B7in H.armigera by 2-tridecanone.The promoter region of CYP6B7was cloned by genome walking technique and analyzed by transient transfeetion assay.Progressive 5'deletion of the promoter region of CYP6B7revealed that the relative luciferase activity of construct -320/+232could be significantly induced by 2-trideeanone.Further stepwise deletion between -320 and -238 bp found that construct -292/+232 could also be significantly induced by 2-tridecanone,but the adjacent construct -256/+232could not,suggesting the essential role of the sequence between -292 and --257 bp for 2-tridecanone induction. Nucleotide mutations between -292 and -281 bp had no influence on the induction ef- fect by 2-tridecanone,but nucleotide mutations between -280 and -257 bp significantly decreased the induction effect.These results demonstrated that the cis-acting element for 2-trideeanone induction was between -280 and -257 bp in the promoter of CYP6B7.

Isolation of cDNAs Enconding Two Distinct Transcription Factors Binding to DRE cis-acting Element Involved in Cold-and drought-induced Expression of Arabidopsis rd29A Gene

Previous study has defined DRE (dehydration responsive element) cis acting element and its important role in expressions of Arabidopsis rd29A gene under cold, dehydration and high salt stresses. In order to clarify the expression mechanism of rd29A gene, we isolated two cDNA clones that encoded DRE binding proteins ( DREB1 and DREB2 ) from cold and drought treated Arabidopsis plants, using DRE cis acting element in the promoter region of rd29A gene and yeast One Hybrid screening method. Experiments showed both DREB1 and DREB2 specifically interacted with DRE cis element. Homologous analysis showed no significant similarity between DREB1 and DREB2 in whole deduced amino acid sequences. However, both DREB1 and DREB2 proteins contained a conserved DNA binding domain (AP2/EREBP domain). Structural analysis of proteins also showed they had a nuclear localization signal (NLS) in their N terminal region and an acidic activation region in their C terminal region. AP2/EREBP domain is composed of 58 amino acids, which presents in a large family of plant genes encoding DNA binding proteins. We analyzed many plant transcription factors containing conserved AP2/EREBP domains. The 14th valine (V) and 19th glutamate (E) in the amino acid sequence of AP2/EREBP domains might be the consensus recognizing and binding to DRE cis element. Northern analysis indicated that DREB1 gene was induced by low temperature, whereas DREB2 gene was induced by dehydration and high salt stresses. Present studies suggest that the expression of rd29A gene under low temperature, dehydration and high salt stresses is regulated by DREB1 and DREB2 transcriptional factors in two separate signal transduction pathways, respectively.

cis-acting element located in the bovine foamy virus internal promoter possesses the properties of a transcrip-tional enhancer

Bovine foamy virus encodes a transcriptional transactivitor, Tas or Borf-1, which governs the level of viral transcripts initiated by both the promoter in the long terminal repeat (LTR) and the internal promoter (IP) located in the env gene through their cis-acting targets. We have identified and characterized a 72 bp TBS (Borf-1) responsive element located in BFV3026, internal promoter (TREIP) by deletion mutant and transient expression assay. This cis-acting target element in the internal promoter has the properties of a transcriptional enhancer which functions independently of its orientation, position and also in heterologous promoters (BFV LTR and bovine immunodeficiency virus, BIV LTR). Alignments reveal that there are positional similarity and sequence homology among BFV TREIP, SFV-1 TREIP proximal element and SFV-3 TREIPH, which suggests that this kind of cis-acting elements possesses some common functional character.

Paleoenvironmental Characteristics of Paleogene Lacustrine Source Rocks in the Western Bozhong Sag,Bohai Bay Basin,China:Evidence from Biomarkers,Major and Trace Elements

The organic matter(OM)enrichment mechanisms and depositional environment characteristics of lacustrine source rocks in the western Bozhong Sag,Bohai Bay Basin in Northeast China remain controversial.To address these issues,based on Rock-Eval pyrolysis,kerogen macerals,H/C and O/C ratios,GC-MS,major and trace elements,the Dongying Formation Member(Mbr)3(E_(3)d_(3)),the Shahejie Formation mbrs 1 and 2(E_(2)s_(1+2)),and the Shahejie Mbr 3(E_(2)s_(3))source rocks in the western Bozhong Sag were studied.The above methods were used to reveal their geochemical properties,OM origins and depositional environments,all of which indicate that E_(2)s_(1+2)and E_(2)s_(3)are excellent source rocks,and that E_(3)d_(3)is of the second good quality.E_(3)d_(3)source rocks were formed under a warm and humid climate,mainly belong to fluvial/delta facies,the E_(3)d_(3)sediments formed under weakly oxidizing and freshwater conditions.Comparatively,the depositional environments of E_(2)s_(1+2)source rocks were arid and cold climate,representing saline or freshwater lacustrine facies,and the sediments of E_(2)s_(1+2)belong to anoxic or suboxic settings with large evaporation and salinity.During the period of E_(2)s_(3),the climate became warm and humid,indicating the freshwater lacustrine facies,and E_(2)s_(3)was characterized by freshwater and abundant algae.Moreover,compared with other intervals,the OM origin of E_(3)d_(3)source rocks has noticeable terrestrial input.The OM origin of the E_(2)s_(1+2)and E_(2)s_(3)are mainly plankton and bacteria.Tectonic subsidence and climate change have affected the changes of the depositional environment in the western Bozhong Sag,thus controlling the distribution of the source rocks,the geochemical characteristics in the three intervals of lacustrine source rocks have distinct differences.Overall,these factors are effective to evaluate the paleoenvironmental characteristics of source rocks by biomarkers,major and trace elements.The established models may have positive implications for research of lacustrine source rocks in offshore areas with few drillings.

Enriched Constant Elements in the Boundary Element Method for Solving 2D Acoustic Problems at Higher Frequencies

The boundary element method(BEM)is a popular method for solving acoustic wave propagation problems,especially those in exterior domains,owing to its ease in handling radiation conditions at infinity.However,BEM models must meet the requirement of 6–10 elements per wavelength,using the conventional constant,linear,or quadratic elements.Therefore,a large storage size of memory and long solution time are often needed in solving higher-frequency problems.In this work,we propose two new types of enriched elements based on conventional constant boundary elements to improve the computational efficiency of the 2D acoustic BEM.The first one uses a plane wave expansion,which can be used to model scattering problems.The second one uses a special plane wave expansion,which can be used tomodel radiation problems.Five examples are investigated to showthe advantages of the enriched elements.Compared with the conventional constant elements,the new enriched elements can deliver results with the same accuracy and in less computational time.This improvement in the computational efficiency is more evident at higher frequencies(with the nondimensional wave numbers exceeding 100).The paper concludes with the potential of our proposed enriched elements and plans for their further improvement.

Robust T_c in element molybdenum up to 160 GPa

Element superconductors with the single atoms provide clean and fundamental platforms for studying superconductivity.Although elements with d electrons are usually not favored by conventional BCS,the record superconducting critical temperature(T_(c))in element scandium(S_(c))has further ignited the intensive attention on transition metals.The element molybdenum(M_o)with a half-full d-orbital is studied in our work,which fills the gap in the study of Mo under high pressure and investigates the pressure dependence of superconductivity.In this work,we exhibit a robust superconductivity of Mo in the pressure range of 5 GPa to 160 GPa via high-pressure electrical transport measurements,the T_(c) varies at a rate of0.013 K/GPa to 8.56 K at 160 GPa.Moreover,the superconductivity is evidenced by the T_(c) shifting to lower temperature under applied magnetic fields,and the upper critical magnetic fields are extrapolated by the WHH equation and GL equation;the results indicate that the maximum upper critical magnetic field is estimated to be 8.24 T at 137 GPa.We further investigate the superconducting mechanism of Mo,the theoretical calculations indicate that the superconductivity can be attributed to the strong coupling between the electrons from the partially filled d band and the phonons from the frequency zone of 200-400 cm^(-1).

Galerkin-based quasi-smooth manifold element(QSME)method for anisotropic heat conduction problems in composites with complex geometry

The accurate and efficient analysis of anisotropic heat conduction problems in complex composites is crucial for structural design and performance evaluation. Traditional numerical methods, such as the finite element method(FEM), often face a trade-off between calculation accuracy and efficiency. In this paper, we propose a quasi-smooth manifold element(QSME) method to address this challenge, and provide the accurate and efficient analysis of two-dimensional(2D) anisotropic heat conduction problems in composites with complex geometry. The QSME approach achieves high calculation precision by a high-order local approximation that ensures the first-order derivative continuity.The results demonstrate that the QSME method is robust and stable, offering both high accuracy and efficiency in the heat conduction analysis. With the same degrees of freedom(DOFs), the QSME method can achieve at least an order of magnitude higher calculation accuracy than the traditional FEM. Additionally, under the same level of calculation error, the QSME method requires 10 times fewer DOFs than the traditional FEM. The versatility of the proposed QSME method extends beyond anisotropic heat conduction problems in complex composites. The proposed QSME method can also be applied to other problems, including fluid flows, mechanical analyses, and other multi-field coupled problems, providing accurate and efficient numerical simulations.

Trace elements in magmatic and hydrothermal quartz:Implications on the genesis of the Xingluokeng Tungsten Deposit,South China

The Xingluokeng deposit is the largest gran-ite-related tungsten deposit within the Wuyi metallogenic belt in South China.The Xingluokeng intrusion primarily consists of porphyritic biotite granite,biotite granite,andfine-grained granite.The deposit is represented by veinlet-disseminated mineralization with K-feldspathization and biotitization,alongside quartz-vein mineralization with gre-isenization and sericitization.This study investigates in-situ analyses of quartz compositions from both the intrusion and hydrothermal veinlets and veins.Trace element correlations indicate that trivalent Al^(3+)and Fe^(3+)replace Si^(4+)within the quartz lattice,with monovalent cations(such as Li^(+),Na^(+),and K^(+))primarily serving as charge compensators.Low Ge/Al ratios(<0.013)of quartz from granites suggest a mag-matic origin.The low Al/Ti and Ge/Ti ratios,accompanied by high Ti contents in quartz,suggest that the porphyritic biotite granite and biotite granite are characterized by rela-tively low levels of differentiation and high crystallization temperatures.In contrast,thefine-grained granite exhibits a higher degree of fractionation,lower crystallization tem-peratures,and a closer association with tungsten miner-alization.Ti contents in quartz from quartz veins indicate Qz-Ⅰformed at temperatures above 400°C,while Qz-Ⅱto Qz-Ⅴformed at temperatures below 350°C.Variations in different generations of quartz,as indicated by Al content and(Al+Fe)/(Li+Na+K)ratio,suggest that Qz-Ⅰprecipi-tated from a less acidicfluid with a stable pH,whereas Qz-Ⅱto Qz-Ⅴoriginated from a more acidicfluid with notable pH variations.Consequently,alkaline alteration and acidic alteration supplied the essential Ca and Fe for the precipita-tion of scheelite and wolframite,respectively,highlighting a critical mechanism in tungsten mineralization at the Xin-gluokeng deposit.

Distribution, health and ecological risk assessments of trace elements in Nigerian oil sands

The Nigerian oil sands represent the largest oil sand deposit in Africa, yet there is little published information on the distribution and potential health and ecological risks of trace elements in the oil resource. In the present study, we investigated the distribution pattern of 18trace elements(including biophile and chalcophile elements) as well as the estimated risks associated with exposure to these elements. The results of the study indicated that Fe was the most abundant element, with a mean concentration of 22,131 mg/kg while Br had the lowest mean concentration of 48 mg/kg. The high occurrence of Fe and Ti suggested a possible occurrence of ilmenite(Fe TiO_(3)) in the oil sands. Source apportionment using positive matrix factorization showed that the possible sources of detected elements in the oil sands were geogenic, metal production, and crustal. The contamination factor, geo-accumulation index, modified degree of contamination, pollution load index, and Nemerow pollution index indicated that the oil sands are heavily polluted by the elements. Health risk assessment showed that children were relatively more susceptible to the potentially toxic elements in the oil sands principally via ingestion exposure route(HQ > 1E-04). Cancer risks from inhalation are unlikely due to CR < 1E-06 but ingestion and dermal contact pose severe risks(CR > 1E-04). The high concentrations of the elements pose serious threats due to the potential for atmospheric transport, bioaccessibility, and bioavailability.

Pig H3K4me3,H3K27ac,and gene expression profiles reveal reproductive tissue-specific activity of transposable elements

Regulatory sequences and transposable elements(TEs)account for a large proportion of the genomic sequences of species;however,their roles in gene transcription,especially tissue-specific expression,remain largely unknown.Pigs serve as an excellent animal model for studying genomic sequence biology due to the extensive diversity among their wild and domesticated populations.Here,we conducted an integrated analysis using H3K27ac ChIP-seq,H3K4me3 ChIP-seq,and RNA-seq data from 10 different tissues of seven fetuses and eight closely related adult pigs.We aimed to annotate the regulatory elements and TEs to elucidate their associations with histone modifications and mRNA expression across different tissues and developmental stages.Based on correlation analysis between mRNA expression and H3K27ac and H3K4me3 peak activity,results indicated that H3K27ac exhibited stronger associations with gene expression than H3K4me3.Furthermore,1.45%of TEs overlapped with either the H3K27ac or H3K4me3 peaks,with the majority displaying tissue-specific activity.Notably,a TE subfamily(LTR4C_SS),containing binding motifs for SIX1 and SIX4,showed specific enrichment in the H3K27ac peaks of the adult and fetal ovaries.RNA-seq analysis also revealed widespread expression of TEs in the exons or promoters of genes,including 4688 TE-containing transcripts with distinct development stage-specific and tissue-specific expression.Of note,1967 TE-containing transcripts were enriched in the testes.We identified a long terminal repeat(LTR),MLT1F1,acting as a testis-specific alternative promoter in SRPK2(a cell cycle-related protein kinase)in our pig dataset.This element was also conserved in humans and mice,suggesting either an ancient integration of TEs in genes specifically expressed in the testes or parallel evolutionary patterns.Collectively,our findings demonstrate that TEs are deeply embedded in the genome and exhibit important tissue-specific biological functions,particularly in the reproductive organs.

Mobility of Major and Trace Elements during the Bauxitization Processes in Ngaoundal Area (Adamawa Cameroon): Implication on Mining Perspectives

This study was focused to assess major and trace elements in bauxitic duricrusts from Ngaoundal and its surroundings in order to establish their mining interest. To this end, fieldworks, mineralogical and geochemical analyses were carried out. Four facies of duricrust were identified and characterized from the summit to the top of the slope of the Ngaoundal mountain: scoriaceous, pisolitic, nodular and massive. Mineralogical and geochemical analyses performed on 16 samples, revealed a significant concentration of Al2O3 mainly in the scoriaceous facies (over 45% in grade), moderate in Fe2O3 (averaging 23.69%) and SiO2 (averaging 21.7%). Trace elements were generally low, excluding Cr (421 ppm on average), Zr (327 ppm on average and V (213 ppm on average). In addition, the limited quantities of alkalis (Na2O, K2O) and alkaline earths metals (MgO, CaO) coupled with the very high values of Chemical Index of Alteration (CIA) and Mineralogical Index of Alteration (MIA), (more than 99%) attest to the intense weathering of the studied materials. Allitization and monosiallitization constituted the crystallochemical phenomena that have led to the development of bauxitic minerals. More than 90% of gibbsite in scoriaceous facies, 52.21% - 76.01% of kaolinite in pisolitic facies and more than 40% of hematite in nodular facies were quantified. The relationships between the constitutive components indicated their interdependency during the bauxitization phenomenon. The mineralogical and geochemical properties highlighted the mining interest of the studied duricrusts to be valorized.

Multi-Elemental Analysis and 2D Image Mapping within Roots, Leaves and Seeds from O. glaberrima Rice Plants Using Micro-PIXE Technique

Understanding metal accumulation at organ level in roots, leaves and seeds in O. glaberrima (OG) is crucial for improving physiological and metabolic aspects in growing Asian and African rice in salted areas. The micro-analytical imaging techniques are required to reveal its accumulation and distribution within plant tissues. PIXE studies have been performed to determine different elements in rice plants. The existing microbeam analytical technique at the iThemba LABS will be applied for the 2D image mapping of fresh rice tissues to perform a concentration of low atomic mass elements (such as Al, Si, P, S, Cl, Ca, Ti, Mn, Fe, Cu, Br, Zn and K) with detection limits of typically 1-10 μg/g. Comparison of the distribution of the elements between leaves, root and seed samples using uptake and distribution of elements in particular environmental conditions with potential amount of salt in water have been performed. We are also expecting to indicate metal exclusion as salt tolerance strategies from leaves, root, and seed compartments using matrix correlation between samples and between elements on rice species.

Finite Element Method Simulation of Wellbore Stability under Different Operating and Geomechanical Conditions

The variation of the principal stress of formations with the working and geo-mechanical conditions can trigger wellbore instabilities and adversely affect the well completion.A finite element model,based on the theory of poro-elasticity and the Mohr-Coulomb rock damage criterion,is used here to analyze such a risk.The changes in wellbore stability before and after reservoir acidification are simulated for different pressure differences.The results indicate that the risk of wellbore instability grows with an increase in the production-pressure difference regardless of whether acidification is completed or not;the same is true for the instability area.After acidizing,the changes in the main geomechanical parameters(i.e.,elastic modulus,Poisson’s ratio,and rock strength)cause the maximum wellbore instability coefficient to increase.

Elemental Compositions of Clinopyroxenes from Southern Okinawa Trough Basalt:Implications for Magmatism and Structural Environment in an Initial Back-Arc Basin

The major and trace elemental compositions of clinopyroxene from basalt were used to characterize the nature of the primitive magma and structural environment beneath the southern Okinawa Trough(SOT),which is an initial back-arc basin at a continental margin.The clinopyroxenes in the basalt were augite with variable Mg^(#)contents(73.37-78.22).The regular variations in major oxide contents(i.e.,CaO,FeO,TiO_(2),and Cr)with decreasing Mg#implied that the clinopyroxenes evolved from being enriched in Mg,Ca,and Cr to being enriched in Fe and Ti.The clinopyroxenes had relatively low rare earth element concentrations(7.51×10^(-6) to 12.68×10^(-6))and negative Eu anomalies(δEu=0.67-0.95).The Kd_(cpx) values of clinopyroxenes(0.2-0.26),which were used to examine whether the clinopyroxene was equilibrated with its host basalt,demonstrate that these clinopyroxene phenocrysts were not captured crystals but were instead produced by crystallization differentiation of the magma.The calculated clinopyroxene crystallization temperatures showed a narrow range of 990-1061℃,and their crystallization pressures ranged from 2.0 to 3.2 kbar.The geochemistry features of these clinopyroxenes indicated that the parent magma belonged to the subalkaline tholeiitic magma series and suggested that the magma experienced crystallization differentiation of olivine,plagioclase,and clinopyroxene,where the crystallization of plagioclase occurred earlier than that of clinopyroxene.Combined with geophysical data,this research on primitive magma and its crystallization differentiation from clinopyroxene indicates that the SOT is in the stage of‘seafloor spreading’and that basaltic rocks produced from tholeiitic magma represent the generation of oceanic crust.

Investigation of the block toppling evolution of a layered model slope by centrifuge test and discrete element modeling

Primary toppling usually occurs in layered rock slopes with large anti-dip angles.In this paper,the block toppling evolution was explored using a large-scale centrifuge system.Each block column in the layered model slope was made of cement mortar.Some artificial cracks perpendicular to the block column were prefabricated.Strain gages,displacement gages,and high-speed camera measurements were employed to monitor the deformation and failure processes of the model slope.The centrifuge test results show that the block toppling evolution can be divided into seven stages,i.e.layer compression,formation of major tensile crack,reverse bending of the block column,closure of major tensile crack,strong bending of the block column,formation of failure zone,and complete failure.Block toppling is characterized by sudden large deformation and occurs in stages.The wedge-shaped cracks in the model incline towards the slope.Experimental observations show that block toppling is mainly caused by bending failure rather than by shear failure.The tensile strength also plays a key factor in the evolution of block toppling.The simulation results from discrete element method(DEM)is in line with the testing results.Tensile stress exists at the backside of rock column during toppling deformation.Stress concentration results in the fragmented rock column and its degree is the most significant at the slope toe.

Effective Elimination of Hazardous Chromium (VI) Using Periodic Elements and Contemporary Adsorption Methods by Using Magnesium Ferrite Nanoparticle: A Review

A well-known hazardous metal and top contaminant in wastewater is hexavalent chromium. The two forms of most commonly found chromium are chromate ( CrO 4 2− ) and dichromate ( Cr 2 O 7 2− ). Leather tanning, cooling tower blow-down, plating, electroplating, rinse water sources, anodizing baths etc. are the main sources of Cr (VI) contamination. The Cr (VI) is not only non-biodegradable in the environment but also carcinogenic to living population. It is still difficult to treat Cr contaminated waste water effectively, safely, eco-friendly, and economically. As a result, many techniques have been used to treat Cr (VI)-polluted wastewater, including adsorption, chemical precipitation, coagulation, ion-exchange, and filtration. Among these practices, the most practical method is adsorption for the removal of Cr (VI) from aqueous solutions, which has gained widespread acceptance due to the ease of use and affordability of the equipment and adsorbent. It has been revealed that Fe-based adsorbents’ oxides and hydroxides have high adsorptive potential to lower Cr (VI) content below the advised threshold. Fe-based adsorbents were also discovered to be relatively cheap and toxic-free in Cr (VI) treatment. Fe-based adsorbents are commonly utilized in industry. It has been discovered that nanoparticles of Fe-, Ti-, and Cu-based adsorbents have a better capacity to remove Cr (VI). Cr (VI) was effectively removed from contaminated water using mixed element-based adsorbents (Fe-Mn, Fe-Ti, Fe-Cu, Fe-Zr, Fe-Cu-Y, Fe-Mg, etc.). Initial findings suggest that Cr (VI) removal from wastewater may be accomplished by using magnesium ferrite nanomaterials as an efficient adsorbent.

A Deep Learning Approach to Shape Optimization Problems for Flexoelectric Materials Using the Isogeometric Finite Element Method

A new approach for flexoelectricmaterial shape optimization is proposed in this study.In this work,a proxymodel based on artificial neural network(ANN)is used to solve the parameter optimization and shape optimization problems.To improve the fitting ability of the neural network,we use the idea of pre-training to determine the structure of the neural network and combine different optimizers for training.The isogeometric analysis-finite element method(IGA-FEM)is used to discretize the flexural theoretical formulas and obtain samples,which helps ANN to build a proxy model from the model shape to the target value.The effectiveness of the proposed method is verified through two numerical examples of parameter optimization and one numerical example of shape optimization.