Epidemiology of carbapenem-resistant Klebsiella pneumoniae in China and the evolving trends of predominant clone ST11: a multicentre, genome-based study.

OBJECTIVES: Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a major nosocomial infectious pathogen with rapidly increasing prevalence. The genomic epidemiological characteristics of CRKP nationwide, especially the evolving trends within the predominant clones, should be evaluated clearly. METHODS: We collected 3415 K. pneumoniae strains from 28 hospitals across China. Antimicrobial susceptibility testing and WGS were performed. Subsequent genomic analyses, including sequence typing, K-locus (KL) identification, antimicrobial resistance gene screening, and virulence score assessment were performed. The phylogenetic relationship of clonal group 11 was determined based on core-genome analysis, and the presence of the pLVPK-like virulence plasmid in ST11 isolates was confirmed using plasmid core-gene analysis. Additionally, the trends of the ST11 lineage with different KL types on a global scale were investigated using Beast2. RESULTS: Of the K. pneumoniae strains, 708 were identified as CRKP isolates (20.7%), of which 97.7% were MDR. ST11 was the predominant clone, and KPC-2 was the prevalent carbapenemase in China, although the prevalence of specific clones and carbapenemases varied by geographic region. Among ST11 isolates, KL47 and KL64 were the predominant KL types, and KL64 gradually replaced KL47, with a higher percentage of KL64 isolates harbouring the pLVPK-like plasmid. Global genome data showed a significant increase in the effective population size of KL64 over the last 5 years. CONCLUSIONS: The prevalence of CRKP was very high in certain regions in China. The increasing convergence of virulence and resistance, particularly in ST11-KL64 isolates, should be given more attention and further investigation.

One-step fabrication of millimeter-scale hollow vesicles with chitosan /DADMAC/ sodium alginate graft copolymer for enhanced anionic dye adsorption.

Hollow vesicles are promising in water treatment due to their unique structure of the membrane and inner cavity. However, the adsorption capacity needs to be improved for targeted pollutants. Herein, millimeter-scale hollow vesicles were prepared with a one-step process of sequential stirring and grafting using chitosan, diallyldimethylammonium chloride, and sodium alginate as raw materials with the purpose of efficient removal of anionic dyes from wastewater. The composite vesicles were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. The hollow vesicles showed the structure of the cationic membrane and the inner cavity, facilitating the dye adsorption. The adsorption capacity for the anionic dye Reactive Black 5 reached 698.1 mg/g, more than twice that of the binary composite vesicles without graft. The adsorption kinetics and isotherm data coincided with the pseudo-second-order and Langmuir models, respectively, and the adsorption mechanism was monolayer chemisorption. Moreover, the vesicles worked well in wide ranges of environment pH, temperature, and co-existing pollutants. They also possessed excellent cyclic regeneration performance, in which 93 % of the initial adsorption capacity was maintained after four cycles. These results indicate that the millimeter-scale hollow vesicles exhibit broad application prospects for wastewater purification.

Enhanced dye adsorption with conductive polyaniline doped chitosan nanofibrous membranes.

Polyaniline is widely used in the field of electrochemistry due to its excellent electrical conductivity. However, its effectiveness and mechanism of enhancing adsorption property are unclear. Herein, chitosan/polyaniline nanofibrous composite membranes with average diameter ranging from 200 to 300 nm were fabricated by electrospinning technology. The as-prepared nanofibrous membranes exhibited significantly improved adsorption capacity of 814.9 mg/g and 618.0 mg/g towards acid blue 113 and reactive orange dyes, which were 121.8 % and 99.4 % higher than that of pure chitosan membrane. The doped polyaniline promoted the dye transfer rate and capacity due to the enhanced conductivity of the composite membrane. Kinetic data showed that chemisorption was the rate-limiting step, and thermodynamic data indicated the adsorption of the two anionic dyes was spontaneous monolayer adsorption. This study provides a feasible strategy to introduce conductive polymer into adsorbent to construct high performance adsorbents for wastewater treatment.

High performance, cost-effective and ecofriendly flocculant synthesized by grafting carboxymethyl cellulose and alginate with itaconic acid.

Natural polymer flocculant possesses an exciting prospect in water treatment due to its non-toxicity, wide source, low cost and biodegradability. In this work, we have successfully synthesized the anionic terpolymer of carboxymethyl cellulose-itaconic acid­sodium alginate (CIS) by microwave-assisted copolymerization. By studying the flocculation properties towards cationic dye of crystal violet (CV), the optimum synthesis conditions were determined. The maximum removal rate of 100 mg/L CV simulated wastewater was 92.2 % with CIS concentration of 30 mg/L. The flocculation kinetic results showed the rapid dye removal rate and the dye decolorization ratio of 89.8 % could be obtained at 75 s. Moreover, the CIS flocculant showed excellent flocculation effects in ambient pH of 4-10, flocculation temperature of 10-40 °C, and various inorganic salts. In general, the anionic CIS flocculant shows excellent cost effectiveness, where the predicted operation cost of as-prepared CIS is about 60 % of conventional polyacrylamide flocculant. It also has the advantages of excellent ecofriendliness and rich raw material source, indicative its potential applications of wastewater treatment.

Current treatment of chronic hepatitis B: Clinical aspects and future directions.

Hepatitis B virus (HBV) infection is a public health threat worldwide, and there is no direct treatment yet available. In the event of infection, patients may present liver cirrhosis and cancer, which threaten the patients' health globally, especially in the Asia-Pacific region and China. In 2019, Chinese hepatopathologists updated the 2015 Guidelines for the Prevention and Treatment of Chronic Hepatitis B as the clinical reference. The other versions formulated by the American Association for the Study of Liver Diseases (2018 AASLD guidelines) (AASLD, 2018), European Association for the Study of the Liver (2017 EASL guidelines) (EASL, 2017), and Asian-Pacific Association for the Study of the Liver (2015 APASL guidelines) (APASL, 2015) also provide clinical guidance. However, there are still some issues that need to be addressed. In the present study, the following aspects will be introduced successively: (1) Who should be treated in the general population according to the guidelines; (2) Treatment of specific populations infected with HBV; (3) Controversial issues in clinical practice; (4) Perspective.

Preparation of carboxymethyl cellulose/chitosan-CuO giant vesicles for the adsorption and catalytic degradation of dyes.

To effectively remove the dyes from wastewater, novel carboxymethyl cellulose/chitosan-CuO giant vesicles with dual function of adsorption and catalytic degradation were prepared. The vesicles were facilely obtained via blending chitosan solution and carboxymethyl cellulose/CuO mixed solution with sequent fast and slow stirring. The removal ratios of methyl orange (MO) and acid black-172 (AB) can reach 86.3% and 88.6% with the catalytic oxidation system of ammonium persulfate and vesicles. Compared with the CuO catalysis without the vesicles, the degradation rates of MO and AB increased by 1.3 and 3.1 times, respectively. The enhanced dye removal is ascribed to the excellent dye adsorption capacity of giant vesicles. Furthermore, the giant vesicles worked well in wide ranges of environmental pH and temperature, and exhibited excellent stability and reusability. This study provides a facile method to load catalyst onto polymeric giant vesicle with outstanding performance for the adsorption and catalytic degradation of dyes.

Polycyclic Phenol Derivatives from the Leaves of Spermacoce latifolia and Their Antibacterial and α-Glucosidase Inhibitory Activity.

Three new polycyclic phenol derivatives, 2-acetyl-4-hydroxy-6H-furo [2,3-g]chromen-6-one (1), 2-(1',2'-dihydroxypropan-2'-yl)-4-hydroxy-6H-furo [2,3-g][1]benzopyran-6-one (2) and 3,8,10-trihydroxy-4,9-dimethoxy-6H-benzo[c]chromen-6-one (8), along with seven known ones (3-7, 9 and 10) were isolated for the first time from the leaves of Spermacoce latifolia. Their structures were determined by spectroscopic analysis and comparison with literature-reported data. These compounds were tested for their in vitro antibacterial activity against four Gram-(+) bacteria: Staphyloccocus aureus (SA), methicillin-resistant Staphylococcus aureus (MRSA), Bacillus cereus (BC), Bacillus subtilis (BS), and the Gram-(-) bacterium Escherichia coli. Compounds 1, 2, 5 and 8 showed antibacterial activity toward SA, BC and BS with MIC values ranging from 7.8 to 62.5 µg/mL, but they were inactive to MRSA. Compound 4 not only showed the best antibacterial activity against SA, BC and BS, but it further displayed significant antibacterial activity against MRSA (MIC 1.95 µg/mL) even stronger than vancomycin (MIC 3.9 µg/mL). No compounds showed inhibitory activity toward E. coli. Further bioassay indicated that compounds 1, 4, 5, 6, 8 and 9 showed in vitro α-glucosidase inhibitory activity, among which compound 9 displayed the best α-glucosidase inhibitory activity with IC50 value (0.026 mM) about 15-fold stronger than the reference compound acarbose (IC50 0.408 mM). These results suggested that compounds 4, 8 and 9 were potentially highly valuable compounds worthy of consideration to be further developed as an effective anti-MRSA agent or effective α-glucosidase inhibitors, respectively. In addition, the obtained data also supported that S. latifolia was rich in structurally diverse bioactive compounds worthy of further investigation, at least in searching for potential antibiotics and α-glucosidase inhibitors.

Electrospun molecularly imprinted sodium alginate/polyethylene oxide nanofibrous membranes for selective adsorption of methylene blue.

Molecular imprinting technique is an efficient method to improve the selective adsorption capacity for the target pollutant. In this study, sodium alginate/polyethylene oxide molecularly imprinted nanofibrous membrane (SA/PEO-MINM) with average diameter of 185 ± 20 nm was successfully synthesized by electrospinning for selective adsorption of methylene blue (MB). Benefiting from the molecular imprinted technology, the adsorption amount of SA/PEO-MINM for MB was increased by about 65%, significantly higher than the non-imprinted membrane. Results showed that the adsorption equilibrium could be well fitted with Langmuir isotherm model and the maximum adsorption capacity towards MB was 3186.7 mg/g. Kinetic experiments well complied with the Pseudo second order model. Reusability studies indicated that the removal efficiency of MB could maintain 93% of the original adsorption capacity after four consecutive adsorption/desorption cycles. More importantly, the SA/PEO-MINM with high surface area and specific adsorption recognition sites showed excellent selective adsorption capacity in the adsorption experiment of MB and methylene orange mixed dye solution. In general, the SA/PEO-MINM can be successfully applied for the selective removal of MB from dye wastewater.

Risk factors for infection and mortality caused by carbapenem-resistant Klebsiella pneumoniae: A large multicentre case-control and cohort study.

OBJECTIVES: To elucidate the predictors of carbapenem-resistant Klebsiella pneumoniae (CRKP) infection and help clinicians better identify CRKP infection at an early stage. METHODS: We conducted a multicentre case-control study of 422 patients with CRKP infection and 948 with carbapenem-susceptible K. pneumoniae (CSKP) infection from March to July 2017. Binary logistic regression was used to identify risk factors for CRKP infection. The subgroups of CRKP respiratory infection, intra-abdominal infection, and bloodstream infection were also evaluated. Patients were followed up for 28 days. Independent risk factors for 28-day crude mortality of CRKP infection were analysed using Cox proportional hazards regression models. RESULTS: Longer stay of hospitalization, stay in the intensive care unit (ICU), previous exposure to antibacterial agents (especially carbapenems, quinolones, aminoglycosides, and tigecycline), invasive procedures, intravascular catheter use, tracheotomy, and admission to ICU in the preceding 90 days were risk factors for CRKP infection. Carbapenem exposure was the only common predictor of different types of CRKP infection. The 28-day crude mortality of CRKP infection was 24.2% and was independently associated with sex, admitted unit, and type of infection. CONCLUSIONS: Strict policies for antibiotic use, cautious decisions regarding the implementation of invasive procedures, and careful management of patients with catheters, especially intravascular catheters, are necessary to handle CRKP infection.

Gut microbiome alterations and gut barrier dysfunction are associated with host immune homeostasis in COVID-19 patients.

BACKGROUND: COVID-19 is an infectious disease characterized by multiple respiratory and extrapulmonary manifestations, including gastrointestinal symptoms. Although recent studies have linked gut microbiota to infectious diseases such as influenza, little is known about the role of the gut microbiota in COVID-19 pathophysiology. METHODS: To better understand the host-gut microbiota interactions in COVID-19, we characterized the gut microbial community and gut barrier function using metagenomic and metaproteomic approaches in 63 COVID-19 patients and 8 non-infected controls. Both immunohematological parameters and transcriptional profiles were measured to reflect the immune response in COVID-19 patients. RESULTS: Altered gut microbial composition was observed in COVID-19 patients, which was characterized by decreased commensal species and increased opportunistic pathogenic species. Severe illness was associated with higher abundance of four microbial species (i.e., Burkholderia contaminans, Bacteroides nordii, Bifidobacterium longum, and Blautia sp. CAG 257), six microbial pathways (e.g., glycolysis and fermentation), and 10 virulence genes. These severity-related microbial features were further associated with host immune response. For example, the abundance of Bu. contaminans was associated with higher levels of inflammation biomarkers and lower levels of immune cells. Furthermore, human-origin proteins identified from both blood and fecal samples suggested gut barrier dysfunction in COVID-19 patients. The circulating levels of lipopolysaccharide-binding protein increased in patients with severe illness and were associated with circulating inflammation biomarkers and immune cells. Besides, proteins of disease-related bacteria (e.g., B. longum) were detectable in blood samples from patients. CONCLUSIONS: Our results suggest that the dysbiosis of the gut microbiome and the dysfunction of the gut barrier might play a role in the pathophysiology of COVID-19 by affecting host immune homeostasis.

Simultaneous adsorption for cationic and anionic dyes using chitosan/electrospun sodium alginate nanofiber composite sponges.

The coexistence of anionic and cationic dyes in dye wastewater has highlighted a great necessity to develop amphoteric adsorbents for their simultaneous removal. Herein, an amphoteric composite sponge was successfully fabricated by combining chitosan with electrospun sodium alginate nanofiber using lyophilization in acetic acid/water/dioxane mixed solvents, which owned the abundant functional groups and superior microstructure of interconnected pores and nanoscale fibers, beneficial for the adsorption capacity improvement. The optimum adsorption capacities for Acid Blue-113 and Rhodamine B were 926.2 ± 25.7 mg/g and 695.4 ± 17.0 mg/g, respectively, much higher than that of the controlled sample prepared with chitosan and non-spinning sodium alginate in traditional acetic acid/water solvents. Meanwhile, the sponge provided with the superior adsorption performance under various pH environment and cyclic adsorption. Importantly, it had considerable simultaneous adsorption capacity for binary system containing anionic and cationic dyes. Overall, the chitosan/electrospun sodium alginate nanofiber composite sponge shows potential for complex wastewater treatment.

Comparison of Fecal Collection Methods on Variation in Gut Metagenomics and Untargeted Metabolomics.

Integrative analysis of high-quality metagenomics and metabolomics data from fecal samples provides novel clues for the mechanism underpinning gut microbe-human interactions. However, data regarding the influence of fecal collection methods on both metagenomics and metabolomics are sparse. Six fecal collection methods (the gold standard [GS] [i.e., immediate freezing at -80°C with no solution], 95% ethanol, RNAlater, OMNIgene Gut, fecal occult blood test [FOBT] cards, and Microlution) were used to collect 88 fecal samples from eight healthy volunteers for whole-genome shotgun sequencing (WGSS) and untargeted metabolomic profiling. Metrics assessed included the abundances of predominant phyla and α- and ß-diversity at the species, gene, and pathway levels. Intraclass correlation coefficients (ICCs) were calculated for microbes and metabolites to estimate (i) stability (day 4 versus day 0 within each method), (ii) concordance (day 0 for each method versus the GS), and (iii) reliability (day 4 for each method versus the GS). For the top 4 phyla and microbial diversity metrics at the species, gene, and pathway levels, generally high stability and reliability were observed for most methods except for 95% ethanol; similar concordances were seen for different methods. For metabolomics data, 95% ethanol showed the highest stability, concordance, and reliability (median ICCs = 0.71, 0.71, and 0.65, respectively). Taken together, OMNIgene Gut, FOBT cards, RNAlater, and Microlution, but not 95% ethanol, were reliable collection methods for gut metagenomic studies. However, 95% ethanol was the best for preserving fecal metabolite profiles. We recommend using separate collecting methods for gut metagenomic sequencing and fecal metabolomic profiling in large population studies. IMPORTANCE The choice of fecal collection method is essential for studying gut microbe-human interactions in large-scale population-based research. In this study, we examined the effects of fecal collection methods and storage time at ambient temperature on variations in the gut microbiome community composition; microbial diversity metrics at the species, gene, and pathway levels; antibiotic resistance genes; and metabolome profiling. Our findings suggest using different fecal sample collection methods for different data generation purposes. OMNIgene Gut, FOBT cards, RNAlater, and Microlution, but not 95% ethanol, were reliable collection methods for gut metagenomic studies. However, 95% ethanol was the best for preserving fecal metabolite profiles.

External validation of hepatocellular carcinoma risk scores in patients with chronic hepatitis B virus infection in China.

Several scores have been proposed in untreated or treated patients with chronic hepatitis B (CHB) to predict risks of hepatocellular carcinoma (HCC) occurrence. However, it is still unclear which score suits all chronic hepatitis B virus (HBV)-infected patients well, regardless of whether they are chronic carriers or CHB patients. In this study, we validated and compared the predictability of CU-HCC, REACH-B, PAGE-B and mPAGE-B in patients with chronic HBV infection in China. 1,786 patients with no history of HCC were recruited, with 978 carriers and 808 CHB patients on antiviral therapy. Patients were classified into low- and high-risk groups according to the predefined cut-off values of 5, 8, 10 and 9 for CU-HCC, REACH-B, PAGE-B and mPAGE-B. The median follow-up period was 43.7months, during which 18 (1.0%) patients developed HCC. The areas under the receiver operating characteristic curves (AUROCs) of CU-HCC, REACH-B, PAGE-B and mPAGE-B scores to predict HCC risk at 36 months were 0.815, 0.703, 0.794 and 0.825, respectively (all p < 0.05). No significant difference among AUROCs of these scores was observed except those of mPAGE-B and REACH-B at 36 months. The cumulative incidence of HCC in low- and high- risk groups based on CU-HCC, REACH-B, PAGE-B and mPAGE-B were 0.4% vs. 3.2%, 0.7% vs. 1.5%, 0.2% vs. 1.3%, and 0.2% vs. 1.7% at 36 months, respectively (all p < 0.05, except PAGE-B, log-rant test). Both CU-HCC and mPAGE-B scores accurately predict HCC risk in Chinese chronic HBV-infected patients. Patients with CU-HCC <5 or mPAGE-B <9 could be exempt from HCC surveillance within 36 months.

Assessment of Significant Pathway Signaling and Prognostic Value of GNG11 in Ovarian Serous Cystadenocarcinoma.

BACKGROUND: GNG11 (G protein subunit gamma 11) is a member of guanine nucleotide-binding protein (G protein) gamma family. Few studies elucidated the role of GNG11 in human disease, especially in tumors. The present study initially analyzed the function of GNG11 in ovarian serous cystadenocarcinoma. METHODS: The differential expression of GNG11 mRNA in ovarian cancer and normal tissues was evaluated through Oncomine, CCLE, Gepia, UCSC Xena and UALCAN databases. The protein expression of GNG11 was assessed via HPA database. Prognosis analysis was performed by Kaplan-Meier Plotter. Restrict survival analysis to subtypes including tumor grade, cancer stage and TP53 mutation status was then carried out. GSEA enrichment analysis was performed to explore the significant pathways associated with GNG11 in ovarian cancer. Finally, the upstream miRNAs of GNG11 were predicted by DIANA, Target Scan, miRDB and miRWalk databases, and the potential key KEGG pathways were subsequently determined by DIANA. RESULTS: The mRNA expression of GNG11 was down-regulated in ovarian cancer patients (P<0.05). The cancer stage of patients correlated with the expression of GNG11 (P<0.05). Survival analysis indicated that GNG11 high expression statistically shortened the overall survival time of patients (HR=1.26, P=0.0043) compared with low expression group, especially for the patients with earlier stage (HR=2.48, P=0.035) and lower grade (HR=1.72, P=0.0016). Subsequently, the consistent upstream miRNA of GNG11, hsa-miR-22-5p, was predicted from 4 databases. The differential expression profile of hsa-miR-22-5p in blood was observed in ovarian cancer patients. According to the GSEA analysis on GNG11 and KEGG analysis on hsa-miR-22-5p, the consistent pathway of ECM-receptor interaction was observed (all P<0.01). ECM-receptor interaction pathway and differential expression of hsa-miR-22-5p in blood suggested the migration risk of ovarian cancer. CONCLUSION: High expression of GNG11 indicated the poor prognosis of ovarian cancer patients. GNG11 might play a crucial role in the biological process of ovarian serous cystadenocarcinoma by ECM-receptor interaction pathway, thus affecting the prognosis of patients.

Preparation of fibrous chitosan/sodium alginate composite foams for the adsorption of cationic and anionic dyes.

Natural polysaccharide is attractive for preparing the environmentally friendly and highly efficient adsorbent. However, to obtain an efficient amphoteric absorbent for dealing with complex wastewater is still challenging. Herein, fibrous chitosan/sodium alginate composite foams were prepared by lyophilization with ternary acetic acid/water/tetrahydrofuran solvents, which had suitable morphology of interconnected pores and microscale fibers for dye adsorption. The amphoteric composite foams showed high adsorption capacities for both anionic Acid Black-172 (817.0 mg/g) and cationic Methylene Blue (1488.1 mg/g), which were far superior to those of the control samples prepared with traditional solvents of acetic acid/water. The adsorption kinetics and isotherm data showed that the adsorption followed the pseudo-second-order and Langmuir model. Further thermodynamics analysis revealed the adsorption was a spontaneous process. Meanwhile, the foams achieved effective adsorption capacity of AB-172 and MB dyes under a wide range of environmental pH, and maintained high adsorption efficiency even after four cycles. The adsorption mechanism is chemisorption, where the adsorption capacities for the anionic and cationic dyes were dependent on the mass ratio of chitosan to sodium alginate. As a novel amphoteric adsorbent, the fibrous chitosan/sodium alginate composite foam shows the potential to remove both cationic and anionic dyes from wastewaters.

Effects of the COVID-19 Pandemic on Obsessive-Compulsive Symptoms Among University Students: Prospective Cohort Survey Study.

BACKGROUND: The COVID-19 pandemic is associated with common mental health problems. However, evidence for the association between fear of COVID-19 and obsessive-compulsive disorder (OCD) is limited. OBJECTIVE: This study aimed to examine if fear of negative events affects Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) scores in the context of a COVID-19-fear-invoking environment. METHODS: All participants were medical university students and voluntarily completed three surveys via smartphone or computer. Survey 1 was conducted on February 8, 2020, following a 2-week-long quarantine period without classes; survey 2 was conducted on March 25, 2020, when participants had been taking online courses for 2 weeks; and survey 3 was conducted on April 28, 2020, when no new cases had been reported for 2 weeks. The surveys comprised the Y-BOCS and the Zung Self-Rating Anxiety Scale (SAS); additional items included questions on demographics (age, gender, only child vs siblings, enrollment year, major), knowledge of COVID-19, and level of fear pertaining to COVID-19. RESULTS: In survey 1, 11.3% of participants (1519/13,478) scored ≥16 on the Y-BOCS (defined as possible OCD). In surveys 2 and 3, 3.6% (305/8162) and 3.5% (305/8511) of participants had scores indicative of possible OCD, respectively. The Y-BOCS score, anxiety level, quarantine level, and intensity of fear were significantly lower at surveys 2 and 3 than at survey 1 (P<.001 for all). Compared to those with a lower Y-BOCS score (<16), participants with possible OCD expressed greater intensity of fear and had higher SAS standard scores (P<.001). The regression linear analysis indicated that intensity of fear was positively correlated to the rate of possible OCD and the average total scores for the Y-BOCS in each survey (P<.001 for all). Multiple regressions showed that those with a higher intensity of fear, a higher anxiety level, of male gender, with sibling(s), and majoring in a nonmedicine discipline had a greater chance of having a higher Y-BOCS score in all surveys. These results were redemonstrated in the 5827 participants who completed both surveys 1 and 2 and in the 4006 participants who completed all three surveys. Furthermore, in matched participants, the Y-BOCS score was negatively correlated to changes in intensity of fear (r=0.74 for survey 2, P<.001; r=0.63 for survey 3, P=.006). CONCLUSIONS: Our findings indicate that fear of COVID-19 was associated with a greater Y-BOCS score, suggesting that an environment (COVID-19 pandemic) × psychology (fear and/or anxiety) interaction might be involved in OCD and that a fear of negative events might play a role in the etiology of OCD.

Preparation of millimeter-sized chitosan/carboxymethyl cellulose hollow capsule and its dye adsorption properties.

In this study, millimeter-sized chitosan/carboxymethyl cellulose (CTS/CMC) hollow capsules with molar ratio of 1/1 and 1/1.5 were successfully prepared by simple mixing and stirring of positively charged CTS and negatively charged CMC solutions under electrostatic interaction. The hollow capsule exhibited distinct removal performance for three typical dyes of methylene blue, methyl orange and acid blue-113 with different charged functional groups. The dye removal was mainly occurred on the hollow capsule membrane instead of the interior of hollow capsule. Typically, The CTS/CMC hollow capsule showed semi-permeability characteristics for methyl orange adsorption as the porous structure of the hollow capsule membrane. After the dye adsorption, the dyes also can release from the hollow capsules with different rates. The unique performance of CTS/CMC hollow capsule might have potential applications in the dye removal, the mixed dye wastewater separation and drug release.

Microwave assisted copolymerization of sodium alginate and dimethyl diallyl ammonium chloride as flocculant for dye removal.

Flocculant made from natural polymers has the advantages of abundant source, affordable cost and environmental friendliness. In this work, a binary flocculant (sodium alginate-dimethyl diallyl ammonium chloride, SAD) was successfully prepared using microwave assisted free radical copolymerization technique. Based on the flocculation properties of yellow 7GL dye, the synthetic process was optimized with the amount of initiator was 0.8 wt% (equal molar ratio of ammonium peroxydisulfate and sodium bisulfite as complex initiator), sodium alginate: dimethyl diallyl ammonium chloride = 1:1 (molar ratio), and the microwave irradiation time was 18 min at the power of 280 W. The experimental results show that the color removal ratio was 73.5% at the SAD dosage of 425 mg/L for the 100 mg/L yellow 7GL simulated wastewater. The SAD also maintained excellent decolorization ratios under a wide range of flocculant dosage and environmental pH. The flocculation mechanism might be the combination of charge neutralization and bridging effect. The prepared SAD flocculant has the virtues of simple synthesis process, ecofriendliness and high decolorization ratio, which make it broad application prospect in the treatment of dye wastewater.

Chitosan coated polyacrylonitrile nanofibrous mat for dye adsorption.

Chitosan is a promising natural-derived polymer for dye adsorption owing to its rich source, good biodegradablity and high adsorption capacity. However, electrospinning of pure chitosan nanofiber needs high concentration of acid solution and the electrospinning productivity is very low due to its high degree of hydrogen bonding and polycationic nature. To solve the problem, the chitosan coated polyacrylonitrile nanofibrous mat (CPNM) was successfully prepared via a two-step fabrication process of polyacrylonitrile electrospinning and a subsequent chitosan coating. The chitosan was homogeneously adhered onto the PAN nanofibers, which improved the hydrophilicity and adsorption capacity of Acid Blue-113 significantly. The adsorption of Acid Blue-113 on CPNM fitted the pseudo-second-order kinetics model well, and the maximum adsorption capacity of CPNM calculated from the Langmuir isotherm model was 1708 mg/g with the average fiber diameter of 189 nm. The CPNM demonstrate the virtue of simple fabrication process, high adsorption capacity and good reusability, which is a promising adsorbent for dye removal.

In Situ Electrospinning Iodine-Based Fibrous Meshes for Antibacterial Wound Dressing.

For effective application of electrospinning and electrospun fibrous meshes in wound dressing, we have in situ electrospun poly(vinyl pyrrolidone)/iodine (PVP/I), PVP/poly(vinyl pyrrolidone)-iodine (PVPI) complex, and poly(vinyl butyral) (PVB)/PVPI solutions into fibrous membranes by a handheld electrospinning apparatus. The morphologies of the electrospun fibers were examined by SEM, and the hydrophobicity, gas permeability, and antibacterial properties of the as-spun meshes were also investigated. The flexibility and feasibility of in situ electrospinning PVP/I, PVP/PVPI, and PVB/PVPI membranes, as well as the excellent gas permeabilities and antibacterial properties of the as-spun meshes, promised their potential applications in wound healing.