Investigation of the potential regulation of the UDP-glycosyltransferase genes on rice grain size and abiotic stress response.

Uridine diphosphate (UDP) glycosyltransferases (UGTs) are widely involved in various metabolic processes. In the present study, we performed a genome-wide survey and identified 199 Oryza sativa UGT genes (OsUGTs), which were classified into 17 groups. We showed that tandem duplication played a major role in the expansion of the OsUGT family, which experienced purifying selection during the evolution process. 163 OsUGTs were expressed in at least one of the six tested tissues, and were clustered into three groups according to their tissue expression profiles. By using the RFGB database, we identified different haplotypes of seven OsUGTs that were highly expressed in seeds, and showed significant differences in grain size among different haplotypes. Moreover, our results also uncovered differential responses of OsUGTs expression to abiotic stresses and hormone treatments, including drought, salt, cold, heat, ABA, JA and AUXIN. By using quantitative real-time PCR, we further confirmed the differential expression of nine selected OsUGTs under ABA, JA, salt, drought and cold treatments, among which OsUGT5 and OsUGT182 were induced by all these five treatments. Our results provide insight into the role of several UGT genes for physiological responses, which will facilitate to investigate their function in regulating rice development and abiotic stress responses.

Physiologically-based pharmacokinetic modeling to predict the exposure and provide dosage regimens of Ustekinumab in pediatric patients with inflammatory bowel disease.

Ustekinumab (UST), a fully human immunoglobulin G1 κ monoclonal antibody, exhibiting high affinity for the p40 subunit shared by IL-12 and IL-23, which play key roles in the pathogenesis of inflammatory bowel disease (IBD). By scaling the physiologically-based pharmacokinetic modeling (PBPK) model of UST in adult patients with IBD, we aim to predict effective dosages for UST in pediatric patients, thereby offering a more practical dosing regimen for real-world applications. In this work, a PBPK model for UST in adult patients with IBD has been developed using PK-Sim and Mobi. Advanced ontogeny model has been incorporated to extrapolate the model to pediatric patients. The simulation results showed that the fold errors of the predicted and observed values of the area under the curve (AUC) and peak plasma concentration (Cmax) were between 0.79 and 1.73. For children aged 6-18, it is recommended to administer the drug per kilogram of body weight, at the model-recommended dose, to achieve a median AUC similar to that of the adult reference population post-administration. This comprehensive model construction enables us to comprehensively and extensively explore the pharmacokinetic characteristics of UST in pediatric patients of different age groups, providing robust support for clinical applications and personalized drug therapy.

Health perception and restorative experience in the therapeutic landscape of urban wetland parks during the COVID-19 pandemic.

Introduction: The effects of restoration and inspiration in the therapeutic landscape of natural environments on visitors during the COVID-19 pandemic have been well-documented. However, less attention has been paid to the heterogeneity of visitor perceptions of health and the potential impacts of experiences in wetland parks with green and blue spaces on visitors' overall perceived health. In this study, we investigate the impact of the restorative landscapes of wetland parks on visitors' health perceptions in the context of the COVID-19 pandemic. Methods: In our survey, 582 respondents participated in an online questionnaire. We analyzed the respondents' health perceptions in terms of latent class analysis, used multinomial logistic regression to determine the factors influencing the potential categorization of health perceptions, and used structural equation modeling to validate the relationships between health perceptions of different groups and landscape perceptions of wetland parks, restorative experiences, and personality optimistic tendencies. Results: The results identified three latent classes of health perceptions. Gender, marital status, education, occupation, income, distance, frequency of activities, and intensity of activities were significant predictors of potential classes of perceived health impacts among wetland park visitors. Discussion: This study revealed the nature and strength of the relationships between health perception and landscape perception, restorative experience, and dispositional optimism tendencies in wetland parks. These findings can be targeted not only to improve visitor health recovery but also to provide effective references and recommendations for wetland park design, planning, and management practices during and after an epidemic.

A comprehensive investigation of the regulatory roles of OsERF096, an AP2/ERF transcription factor, in rice cold stress response.

KEY MESSAGE: OsERF096 negatively regulates rice cold tolerance and mediates IAA biosynthesis and signaling under cold stress. The APETALA2/ethylene-responsive factor (AP2/ERF) transcription factors play important roles in regulating plant tolerance to abiotic stress. OsERF096 was previously identified as a direct target of miR1320, and was suggested to negatively regulate rice cold tolerance. In this study, we performed RNA-sequencing and targeted metabolomics assays to reveal the regulatory roles of OsERF096 in cold stress response. GO and KEGG analysis of differentially expressed genes showed that the starch and sucrose metabolism, plant-pathogen interaction, and plant hormone signal transduction pathways were significantly enriched. Quantification analysis confirmed a significant difference in sugar contents among WT and OsERF096 transgenic lines under cold treatment. Targeted metabolomics analysis uncovered that IAA accumulation and signaling were modified by OsERF096 in response to cold stress. Expectedly, qRT-PCR assays confirmed significant OsIAAs and OsARFs expression changes in OsERF096 transgenic lines. Finally, we identified three targets of OsERF096 based on RNA-seq, qRT-PCR, and dual-LUC assays. In summary, these results revealed the multiple regulatory roles of OsERF096 in cold stress response.

The conserved evolution of plant H+-ATPase family and the involvement of soybean H+-ATPases in sodium bicarbonate stress responses.

Plant plasma membrane (PM) H+-ATPases are essential pumps involved in multiple physiological processes. They play a significant role in regulating pH homeostasis and membrane potential by generating the electrochemical gradient of the proton across the plasma membrane. However, information on soybean PM H+-ATPase is still limited. In this study, we conducted the evolutionary analysis of PM H+-ATPases in land plants and investigated the subfamily classification and whole genome duplication of PM H+-ATPases in angiosperms. We further characterized the extremely high conservation of the soybean PM H+-ATPase family in terms of gene structure, domain architecture, and protein sequence identity. Using the yeast system, we confirmed the highly conserved biochemical characteristics (14-3-3 binding affinity and pump activity) of soybean PM H+-ATPases and their conserved function in enhancing tolerance to high pH and NaHCO3 stresses. Meanwhile, our results also revealed their divergence in the transcriptional expression in different tissues and under sodium bicarbonate stress. Finally, the function of soybean PM H+-ATPases in conferring sodium bicarbonate tolerance was validated using transgenic Arabidopsis. Together, these results conclude that the soybean PM H+-ATPase is evolutionarily conserved and positively regulates the response to sodium bicarbonate stress.

The relation between barrier-free environment perception and campus commuting satisfaction.

Introduction: The COVID-19 pandemic, which began in the last quarter of 2019, has had a significant impact on urban transportation. With increasing demand for urban transport, the internal roads and public spaces of university campuses play an important role in facilitating commuting and communication between various functional zones. While considerable research has been conducted on route planning, pedestrian-vehicle segregation, and safety management in the internal transportation environment of university campuses, empirical investigations exploring barrier-free inclusive campus environment design and the subjective evaluation of road and public space users in the aftermath of the COVID-19 pandemic are lacking. Recent developments in travel behavior models and positive psychology have led to an increased focus on the correlation among subjective perceptions, attitudes, emotions, and commuting satisfaction in urban transportation and planning design. Methods: To elucidate this relationship, a study was conducted on the new campus of Central South University in Changsha, Hunan Province, China. Using 312 valid samples, a structural equation model was constructed to analyse the relationship between commuting satisfaction and the barrier-free environment perception of university students regarding the internal transportation environment of the campus. Results: The results revealed that individuals' instantaneous barrier-free environment perceptions and long-term established positive emotions had a significant positive effect on commuting satisfaction. Furthermore, positive emotions were found to mediate the relationship between commuting attitudes induced by COVID-19, barrier-free environment perceptions, and commuting satisfaction. Discussion: The results of this study provide a theoretical basis for the necessity of accessibility design in the post-COVID era. In addition, this study considers the perspective of users to provide ideas for the planning and construction of barrier-free campus environments that are based on convenient and inclusive design.

The concentrations of bone calcium, phosphorus and trace metal elements in elderly patients with intertrochanteric hip fractures.

Introduction: Trace metal elements may play a crucial role in bone mineralization and metabolism. However, the quantification of trace element concentrations in human bone tissue has received little attention. Materials and methods: Bone tissue samples were collected from 55 elderly patients (15 males and 40 females) with intertrochanteric hip fractures. The calcium, phosphorus, manganese, iron, copper, and zinc concentrations in the cortical bone zone, cancellous bone zone, and junction zone between cortical and cancellous bone were determined by energy-dispersive X-ray fluorescence (EDX). The differences in trace element concentrations in the three regions were compared, and the correlation between gender and bone trace element contents of the bones was analyzed using the Kruskal-Wallis's test. The correlation between age, body mass index (BMI), and bone calcium, phosphorus concentrations, and trace elements in three bone zones was determined using Spearman correlation analysis. Results: The Kruskal-Wallis test showed no difference in bone phosphorus concentration among the three regions. In contrast, the difference in the concentrations of bone calcium and four metal elements was statistically significant (P<0.01). In addition, no statistical differences were observed in the concentrations of trace elements among the three regions in elderly male and female patients. Spearman correlation analysis showed a strong negative correlation between bone calcium and phosphorus in three bone regions (r=-0.999, -0.95, -0.998, P < 0.01) and a significant positive correlation between trace metal elements in the cancellous bone zone. In the junction zone, the BMI showed a strong positive correlation with bone calcium content (r=0.347, P=0.009) and a significant negative correlation with phosphorus content (r=-0.349, P=0.009). Conclusion: Bone calcium and phosphorus were the main components of hydroxyapatite, and these two elements accounted for the majority of bone mineral salts. Trace metal elements are essential for bone metabolism and specific synergistic interactions. BMI may be associated with bone calcium and phosphorus contents in elderly patients with osteoporosis.

Insights into the regulation of wild soybean tolerance to salt-alkaline stress.

Soybean is an important grain and oil crop. In China, there is a great contradiction between soybean supply and demand. China has around 100 million ha of salt-alkaline soil, and at least 10 million could be potentially developed for cultivated land. Therefore, it is an effective way to improve soybean production by breeding salt-alkaline-tolerant soybean cultivars. Compared with wild soybean, cultivated soybean has lost a large number of important genes related to environmental adaptation during the long-term domestication and improvement process. Therefore, it is greatly important to identify the salt-alkaline tolerant genes in wild soybean, and investigate the molecular basis of wild soybean tolerance to salt-alkaline stress. In this review, we summarized the current research regarding the salt-alkaline stress response in wild soybean. The genes involved in the ion balance and ROS scavenging in wild soybean were summarized. Meanwhile, we also introduce key protein kinases and transcription factors that were reported to mediate the salt-alkaline stress response in wild soybean. The findings summarized here will facilitate the molecular breeding of salt-alkaline tolerant soybean cultivars.

Screening Potential Diagnostic Biomarkers for Age-Related Sarcopenia in the Elderly Population by WGCNA and LASSO.

Background: Sarcopenia is a common chronic disease characterized by age-related decline in skeletal muscle mass and function, and the lack of diagnostic biomarkers makes community-based screening problematic. Methods: Three gene expression profiles related with sarcopenia were downloaded and merged by searching the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) and eigengenes of a module in the merged dataset were identified by differential expression analysis and weighted gene coexpression network analysis (WGCNA), and common genes (CGs) were defined as the intersection of DEGs and eigengenes of a module. CGs were subjected to gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Subsequently, the least absolute shrinkage and selection operator (LASSO) analysis was performed to screen the CGs for identifying the diagnostic biomarkers of sarcopenia. Based on the diagnostic biomarkers, we established a novel nomogram model of sarcopenia. At last, we validated the diagnostic biomarkers and evaluated the diagnostic performance of the nomogram model by the area under curve (AUC) value. Results: We screened out 107 DEGs and 788 eigengenes in the turquoise module, and 72 genes were selected as CGs of sarcopenia by intersection. GO analysis showed that CGs were mainly involved in metal ion detoxification and mitochondrial structure, and KEGG analysis revealed that CGs were mainly enriched in the mineral absorption, glucagon signaling pathway, FoxO signaling pathway, insulin signaling pathway, AMPK signaling pathway, and estrogen signaling pathway. Then, six diagnostic biomarkers (ARHGAP36, FAM171A1, GPCPD1, MT1X, ZNF415, and RXRG) were identified by LASSO analysis. Finally, the validation AUC values indicated that the six diagnostic biomarkers had high diagnostic accuracy for sarcopenia. Conclusion: We identified six diagnostic biomarkers with high diagnostic performance, providing new insights into the incidence and progression of sarcopenia in future research.

Development and Verification of a Combined Diagnostic Model for Sarcopenia with Random Forest and Artificial Neural Network.

Background: Sarcopenia is a chronic disease characterized by an age-related decline in skeletal muscle mass and function, and diagnosis is challenging owing to the lack of a clear "gold standard" assessment method. Objective: This study is aimed at combining random forest (RF) and artificial neural network (ANN) methods to screen key potential biomarkers and establish an early sarcopenia diagnostic model. Methods: Three gene expression datasets were downloaded and merged by searching the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) in the merged dataset were identified by R software and subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Afterward, the STRING database was employed for interaction analysis of the differentially encoded proteins. Then, RF was used to identify key genes from the DEGs, and a sarcopenia diagnostic model was constructed by ANN. Finally, the diagnostic model was assessed using a validation dataset, while its diagnostic performance was evaluated by the area under curve (AUC) value. Results: 107 sarcopenia-related DEGs were identified, and they were mainly enriched in the FoxO and AMPK signaling pathways involved in the molecular pathogenesis of sarcopenia. Thereafter, seven key genes (MT1X, FAM171A1, ZNF415, ARHGAP36, CISD1, ETNPPL, and WISP2) were identified by the RF classifier. The proteins encoded by three of these genes (CISD1, ETNPPL, and WISP2) may be potential biomarkers for sarcopenia. Finally, a diagnostic model for sarcopenia was successfully designed by ANN, achieving an AUC of 0.999 and 0.85 in the training and testing datasets, respectively. Conclusion: We identified several potential genetic biomarkers and successfully developed an early predictive model with high diagnostic performance for sarcopenia. Moreover, our results provide a valuable reference for the early diagnosis and screening of sarcopenia in the future.

Osa-miR1320 targets the ERF transcription factor OsERF096 to regulate cold tolerance via JA-mediated signaling.

MicroRNAs play key roles in abiotic stress response. Rice (Oryza sativa L.) miR1320 is a species-specific miRNA that contributes to miR168-regulated immunity. However, it is still unknown whether miR1320 is involved in rice response to abiotic stress. In this study, we illustrated that the miR1320 precursor generated two mature miR1320s, miR1320-3p, and miR1320-5p, and they both displayed decreased expression under cold stress. Genetic evidence showed that miR1320 overexpression resulted in increased cold tolerance, while miR1320 knock down (KD) reduced cold tolerance. Furthermore, an APETALA2/ethylene-responsive factor (ERF) transcription factor OsERF096 was identified as a target of miR1320 via 5'-RACE and dual luciferase assays. OsERF096 expression was altered by miR1320 overexpression and KD and exhibited an opposite pattern to that of miR1320 in different tissues and under cold stress. Consistently, OsERF096 negatively regulated cold stress tolerance. Furthermore, we suggested that OsERF096 could bind to the GCC and DRE cis-elements and act as a transcriptional activator in the nucleus. Based on RNA-sequencing and targeted metabolomics assays, we found that OsERF096 modified hormone content and signaling pathways. Finally, phenotypic and reverse transcription-quantitative PCR assays showed that jasmonic acid (JA) methyl ester application recovered the cold-sensitive phenotype and JA-activated expression of three Dehydration Responsive Element Binding genes in the OsERF096-OE line. Taken together, our results strongly suggest that the miR1320-OsERF096 module regulates cold tolerance by repressing the JA-mediated cold signaling pathway.

Association between bone turnover markers, BMD and height loss of cemented vertebrae after percutaneous vertebroplasty in patients with osteoporotic vertebral compression fractures.

INTRODUCTION: Percutaneous vertebroplasty (PVP) was recently performed for treating patients with osteoporotic vertebral compression fractures (OVCF). However, recompression of cemented vertebra with significant vertebral height loss occurred in the patients after PVP was observed during the follow-up period. The purpose is to explore the risk factors among several potential predictors for the height loss of treated vertebral bodies after PVP in patients with OVCF. METHODS: A study of 93 patients who had undergone PVP between May 1, 2016, and March 1, 2019, at the Spine Center of Huadong Hospital Affiliated to Fudan University was conducted. The fractured vertebral height loss ratio ≥ 15% at final follow-up were defined as cemented vertebra recompression. The following variables were measured and collected: age, gender, body mass index (BMI), bone mineral density (BMD), volume of bone cement injected, bone cement leakage, fractured vertebra segment, contact between bone cement and endplates, serum of calcium and phosphorus, and six kinds of bone turnover markers. RESULTS: Mann-Whitney U test and Univariate Logistic regression analysis showed that the cemented vertebra recompression was correlated with BMD, contact between bone cement and endplates, parathyroid hormone (PTH), and 25-hydroxy vitamin D3 (25-OH-D3). Following multivariate modeling, multiple factors logistic regression elucidated that high BMD (P < 0.001, OR = 0.089) and high level of serum 25-OH-D3 (P = 0.012, OR = 0.877) were negatively correlated with the cemented vertebra recompression after PVP. CONCLUSION: Decreased BMD and lower level of serum 25-OH-D3 might be two critical and significant risk factors for the height loss of cemented vertebrae after PVP.

Icariin-Loaded Hydrogel Regulates Bone Marrow Mesenchymal Stem Cell Chondrogenic Differentiation and Promotes Cartilage Repair in Osteoarthritis.

Intra-articular injection of mesenchymal stem cells is a potential therapeutic strategy for cartilage protection and symptom relief for osteoarthritis (OA). However, controlling chondrogenesis of the implanted cells in the articular cavity remains a challenge. In this study, hydrogels containing different concentrations of icariin were prepared by in situ crosslinking of hyaluronic acid and Poloxamer 407. This injectable and thermoresponsive hydrogel, as a 3D cell culture system, showed good biocompatibility with chondrocytes and bone marrow mesenchymal stem cells (BMSCs), as well as promoted proliferation and chondrogenesis of BMSCs through the Wnt/ß-catenin signaling pathway. Intra-articular injection of this kind of BMSC-loaded composite hydrogel can significantly prevent cartilage destruction by inducing chondrogenic differentiation of BMSCs, and relieve pain through regulating the expression of inflammatory cytokines (e.g., IL-10 and MMP-13) in the OA model. Incorporating BMSCs into this novel icariin-loaded hydrogel indicates a more superior efficacy than the single BMSC injection, which suggests a great potential for its application in OA.

Genome-Wide Identification, Characterization and Expression Analysis of Soybean CHYR Gene Family.

The CHYR (CHY ZINC-FINGER AND RING FINGER PROTEIN) proteins have been functionally characterized in iron regulation and stress response in Arabidopsis, rice and Populus. However, their roles in soybean have not yet been systematically investigated. Here, in this study, 16 GmCHYR genes with conserved Zinc_ribbon, CHY zinc finger and Ring finger domains were obtained and divided into three groups. Moreover, additional 2-3 hemerythrin domains could be found in the N terminus of Group III. Phylogenetic and homology analysis of CHYRs in green plants indicated that three groups might originate from different ancestors. Expectedly, GmCHYR genes shared similar conserved domains/motifs distribution within the same group. Gene expression analysis uncovered their special expression patterns in different soybean tissues/organs and under various abiotic stresses. Group I and II members were mainly involved in salt and alkaline stresses. The expression of Group III members was induced/repressed by dehydration, salt and alkaline stresses, indicating their diverse roles in response to abiotic stress. In conclusion, our work will benefit for further revealing the biological roles of GmCHYRs.

Students' Intention of Visiting Urban Green Spaces after the COVID-19 Lockdown in China.

This study addresses students' perceptions of using urban green spaces (UGSs) after the easing of COVID-19 lockdown in China. We questioned whether they are still mindful of the risks from the outdoor gathering, or conversely, starting to learn the restoration benefits from the green spaces. Online self-reported surveys were distributed to the Chinese students aging from 14 to 30 who study in Hunan and Jiangsu Provinces, China. We finally obtained 608 complete and valid questionnaire forms from all participants. Their intentions of visiting UGSs were investigated based on the extended theory of planned behavior model. Structural equation modeling was employed to test the hypothesized psychological model. The results have shown good estimation performance on risk perception and perceived knowledge to explain the variances in their attitudes, social norms, and perceived behavior control. Among these three endogenous variables, the perceived behavior control owns the greatest and positive influence on the behavioral intention, inferring that controllability is crucial for students to make decisions of visiting green spaces in a post-pandemic context.

Wild soybean SNARE proteins BET1s mediate the subcellular localization of the cytoplasmic receptor-like kinases CRCK1s to modulate salt stress responses.

Plants have evolved numerous receptor-like kinases (RLKs) that modulate environmental stress responses. However, little is known regarding soybean (Glycine max) RLKs. We have previously identified that Glycine soja Ca2+ /CAM-binding RLK (GsCBRLK) is involved in salt tolerance. Here, we report that soluble NSF attachment protein receptor proteins BET1s mediate subcellular localization of calmodulin-binding receptor-like cytoplasmic kinases CRCK1s to modulate salt stress responses. Direct interaction between GsCBRLK and GsBET11a was initially identified via yeast two-hybrid and bimolecular fluorescence complementation assays. Further analysis demonstrated conserved interaction between BET1s and CRCK1s. GsCBRLK interacted with all BET1 proteins in wild soybean (Glycine soja) and Arabidopsis, and GsBET11a strongly associated with GsCRCK1a-1d, but slightly with AtCRCK1. In addition, GsBET11a interacted with GsCBRLK via its C-terminal transmembrane domain (TMD), where the entire TMD, not the sequence, was critical for the interaction. Moreover, the N-terminal variable domain (VD) of GsCBRLK was responsible for interacting with GsBET11a, and the intensity of interaction between GsCBRLK/AtCRCK1 and GsBET11a was dependent on VD. Furthermore, GsBET11a was able to mediate the GsCBRLK subcellular localization via direct interaction with VD. Additionally, knockout of AtBET11 or AtBET12 individually did not alter GsCBRLK localization, while GsBET11a expression caused partial internalization of GsCBRLK from the plasma membrane (PM). We further suggest the necessity of GsCBRLK VD for its PM localization via N-terminal truncation assays. Finally, GsBET11a was shown to confer enhanced salt stress tolerance when overexpressed in Arabidopsis and soybean. These results revealed the conserved and direct interaction between BET1s and CRCK1s, and suggested their involvement in salt stress responses.

Optimization of Cadmium Adsorption by Magnetic Graphene Oxide Using a Fractional Factorial Design.

Graphene materials have attracted increasing interest in water remediation. In this study, magnetic graphene oxide (MGO) was prepared through the modified Hummers method and the adsorption behaviors of cadmium were investigated. Firstly, the sorption kinetics, isotherms, as well as the effects of pH were investigated. Then, fractional factorial design (FFD) was used to optimize the effects of pH, temperature, time, initial concentration of cadmium ion and NaCl on cadmium adsorption. The results indicate that MGO could effectively remove cadmium ions from an aqueous solution and the sorption data could be described well by pseudo-second-order and Freundlich models, showing that the adsorption rate of cadmium ions on MGO is multilayer adsorption and dominated by the chemical adsorption. According to the FFD results, the maximum adsorption capacity of cadmium ions was 13.169 mg/g under the optimum condition of pH value 8, 45 °C, contact time 60 min, initial cadmium concentration of 70 mg/L and NaCl concentration of 100 mg/L. Higher levels of the pH value, temperature and initial cadmium concentration are beneficial to the adsorption process. These results are important for estimating and optimizing the removal of metal ions by MGO composite.

Coupling of kenaf Biochar and Magnetic BiFeO3 onto Cross-linked Chitosan for Enhancing Separation Performance and Cr(VI) Ions Removal Efficiency.

Cr(VI) contamination has posed great threat to both the ecosystem and human health for its carcinogenic and mutagenic nature. A highly effective adsorbent for the removal of Cr(VI) was prepared and its adsorption mechanism was thoroughly discussed in this study. In detail, magnetic BiFeO3 and kenaf biochar were loaded on cross-linked chitosan to obtain chitosan-kenaf biochar@BiFeO3 (CKB) for improving adsorption capacity towards Cr(VI). The adsorption process of Cr(VI) onto CKB was evaluated as a function of the pH, the existence of competing ions, the initial concentration of Cr(VI) and contact time. The results show that CKB exhibits the highest adsorption capacity under the optimal pH 2.0. The presence of competing ions such as Ca2+, NO3-, SO42-, and Cl- decreases the adsorption capacity; among them, Ca2+ and NO3- show the greatest hindrance. By studying the effect of initial Cr(VI) concentration on the adsorption capacity, it was found that CKB in the solution was enough to remove Cr(VI) for all treatments (10-200 mg/L). The adsorption experimental data were well fitted with pseudo-first-order model, suggesting that chemisorption is not the dominant rate-limiting step. Freundlich isotherm model can better explain the adsorption process, indicating a non-ideal adsorption towards Cr(VI) on a heterogeneous surface of CKB. A 25-1 Fractional Factorial Design (FFD) showed that pH and initial concentration of Cr(VI) have significant influence on Cr(VI) adsorption in our reaction system. In general, excellent adsorption efficiency of CKB indicates that it may be a good candidate for the remediation of Cr(VI)-contaminating wastewater.

Effects of heteroaggregation with metal oxides and clays on tetracycline adsorption by graphene oxide.

Multiple nanoparticles (NPs) often coexist in water with contaminants, which inevitably affect the fate and transport of coexisted contaminants and other types of nanoparticles in actual water. This research was devoted to examine the adsorption of tetracycline (TC) on graphene oxide (GO) in the presence of different amounts of model engineered and natural NPs (m-NPs), including metal oxides (ZnO and Fe2O3), clays (kaolin and montmorillonite). The experimental results proved that the existence of m-NPs greatly enhanced the TC adsorption onto GO except for that at Fe2O3/GO = 10:1 and lengthened the adsorption equilibrium time. The enhanced adsorption amount of TC with increasing m-NPs/GO ratio was primarily due to the adsorption of TC onto m-NPs. In contrast, the slightly inhibitory effects by 10:1 Fe2O3/GO could be attributed to the blockage effect on GO surface by a small amount of Fe2O3. Compared with five m-NPs/adsorbents, m-NPs/GO had the greatest promoting efficiency on TC removal. Moreover, the heteroaggregation of GO with different m-NPs was studied in aqueous phase by microscopic, spectroscopic, and computational methods. Analysis showed that the electrostatic attraction between negatively charged GO and positively charged ZnO were likely to first heteroaggregate in binary systems of GO and ZnO, while GO were prone to homoaggregate owing to electrostatic repulsion with the same negatively charged montmorillonite (or kaolin). Besides, Fe2O3 tended to first homoaggregate and then heteroaggregate with GO. In summary, this report elucidated complex interactions between GO and m-NPs, which was crucial to fundamentally understand towards a predictive framework for describing the fate and migration of GO and m-NPs in actual water.

Three-dimensional microspheric g-C3N4 coupled by Broussonetia papyrifera biochar: facile sodium alginate immobilization and excellent photocatalytic Cr(iv) reduction.

Photocatalysts comprising Broussonetia papyrifera biochar and g-C3N4 loaded on sodium alginate were prepared and characterized in terms of reusability and photocatalytic Cr(vi) reduction performance. The observed photocurrent responses as well as photoluminescence and UV-visible diffuse reflectance spectra showed that the best-performing catalyst featured the benefits of efficient photogenerated charge separation, superior electron conductance/transfer, and excellent light adsorption ability, which resulted in a higher photocatalytic Cr(vi) reduction performance compared to that of pure g-C3N4 powder. The prepared composite was shown to be reusable and well separable from the reaction mixture, thus being a promising material for the practical photocatalytic removal of Cr(vi) from wastewater. The trapping experiment and XPS spectra of catalysts after reactions confirm that the decontamination of Cr(vi) lies in the photocatalytic reduction of this species into low-toxicity Cr(iii) by photoinduced electrons generated from g-C3N4, followed by the adsorption of Cr(iii) on biochar or alginate with large specific areas.