Factors Explaining the Use of Web-Based Consultations With Physicians by Young and Middle-Aged Individuals in China: Qualitative Comparative Analysis.

BACKGROUND: It was only upon the occurrence of the COVID-19 pandemic that the demand for web-based consultations with physicians grew at unprecedented rates. To meet the demand, the service environment developed rapidly during the pandemic. OBJECTIVE: This study aimed to identify the current status of the use of web-based consultations with physicians among young and middle-aged Chinese individuals and explore users' perspectives on key factors that influence its use in terms of optimizing benefits and compensating for disadvantages. METHODS: We conducted semistructured interviews with 65 individuals (aged 18 to 60 years) across China between September and October 2022. The interviewees were selected through snowball sampling. They described their experiences of using web-based physician consultations and the reasons for using or not using the service. Based on the Andersen Behavioral Model, a qualitative comparative analysis was used to analyze the factors associated with the use of web-based physician consultations and explore the combinations of these factors. RESULTS: In all, 31 (48%) of the 65 interviewees used web-based consultation services. The singular necessary condition analysis revealed that the complementary role of the service and perceived convenience are necessary conditions for the use of web-based consultation services, and user's confidence in the service was a sufficient condition. Based on the Andersen Behavioral Model, the configuration analysis uncovered 2 interpretation models: an enabling-oriented model and a need-oriented model. The basic combination of the enabling-oriented model included income and perceived convenience. The basic combination of the need-oriented model included complementary role and user's confidence. CONCLUSIONS: Among the factors associated with the use of web-based consultations, perceived convenience, complementary role, and user's confidence were essential factors. Clear instructions on the conduct of the service, cost regulations, provider qualifications guarantee, privacy and safety supervision, the consultations' application in chronic disease management settings, and subsequent visits can promote the positive development of web-based consultations.

A novel extraction-free dual HiFi-LAMP assay for detection of methicillin-sensitive and methicillin-resistant Staphylococcus aureus.

Staphylococcus aureus (S. aureus) is a leading cause of bacteremia and blood stream infections. Methicillin-resistant S. aureus (MRSA) that first appeared in 1961 often caused hospital-acquired infections (HAIs) and community-acquired infections (CAIs) and was associated with high mortality rate. Accurate and rapid point-of-care testing (POCT) of MRSA is crucial for clinical management and treatment of MRSA infections, as well as the prevention and control of HAIs and CAIs. Here, we reported a novel extraction-free dual HiFi-LAMP assay for discriminative detection of methicillin-susceptible S. aureus and MRSA. The dual HiFi-LAMP assay can detect 30 copies/reaction of nuc and mecA genes with detection limits of 147 and 158 copies per 25 µL reaction, respectively. A retrospective clinical evaluation with 107 clinical S. aureus isolates showed both sensitivity and specificity of 100%. A prospective clinical evaluation with 35 clinical samples revealed a specificity of 100% and a sensitivity of 92.3%. The dual HiFi-LAMP assay can detect almost all S. aureus samples (141/142; 99.3%) within 20 min, implying that the entire HiFi-LAMP assay (including sample process) can be completed within 40 min, extremely significantly shorter than 3-5 days by the traditional clinical microbial culture and antibiotic susceptibility testing. The novel extraction-free dual HiFi-LAMP assay can be used as a robust POCT tool to promote precise diagnosis and treatment of MRSA infections in hospitals and to facilitate surveillance of MRSA at hospital and community settings.IMPORTANCEMethicillin-resistant Staphylococcus aureus (MRSA) was associated with high mortality rate and listed as a "priority pathogen" by the World Health Organization. Accurate and rapid point-of-care testing (POCT) of MRSA is critically required for clinical management and treatment of MRSA infections. Some previous LAMP-based POCT assays for MRSA might be questionable due to their low specificity and the lack of appropriate evaluation directly using clinical samples. Furthermore, they are relatively tedious and time-consuming because they require DNA extraction and lack multiplex detection capacity. Here, we reported a novel extraction-free dual HiFi-LAMP assay for discriminative detection of MRSA and methicillin-susceptible S. aureus. The assay has high specificity and sensitivity and can be completed within 40 min. Clinical evaluation with real clinical samples and clinical isolates showed excellent performance with 100% specificity and 92.3%-100% sensitivity. The novel extraction-free assay may be a robust POCT tool to promote precise diagnosis of MRSA infections and facilitate surveillance of MRSA at hospital and community settings.

Comparative study of trimming and resection of diseased finger superficial flexor tendons in gouty carpal tunnel syndrome.

BACKGROUND: Hyperuricemia can lead to synovial hyperplasia in the wrist. In severe cases, it can lead to the deposition of gouty stone in the carpal tunnel, resulting in increased pressure in the carpal tunnel and compression of the median nerve to cause carpal tunnel syndrome (CTS), which is called gouty carpal tunnel syndrome (GCTS). As for the surgical treatment of gouty carpal tunnel syndrome, scholars have different opinions on whether it is necessary to remove the superficial flexor tendon. The purpose of this study was to compare the clinical efficacy of trimming and resection of the diseased superficial flexor tendon in the treatment of gouty carpal tunnel syndrome. METHODS: Clinical data were collected from May 2016 to July 2021 from 10 patients (13 affected wrists) diagnosed with gouty carpal tunnel syndrome and classified into two groups according to the surgical modality: the diseased portion of the gout-eroded superficial finger tendon was trimmed in 9 wrists, and the diseased superficial finger flexor tendon was excised in 4 wrists. Values related to flexion and extension functions, 2-PD, DASH, BCTQ, VAS and recurrence in the affected fingers were compared between the two groups as well as before and after surgery in each group. RESULTS: All affected limbs used were cleared of gouty stones, finger numbness improved, no skin necrosis occurred, and all incisions healed at stage I. At follow-up (13.58 ± 5.53 months), there was no significant difference between groups in flexion and extension function, 2-PD, DASH, BCTQ, and VAS with respect to the affected fingers, and patients in both groups improved significantly before and after surgery. Treatment of only one wrist involved trimming to remove lesion-affected portions of tendon, which reappeared 1 year after surgery, and there was one case of poor recovery from greater piriformis muscle atrophy in both procedures. CONCLUSION: Regarding surgical treatment of patients with gouty carpal tunnel syndrome in which the gouty stone has invaded the superficial flexor tendons of the fingers, the diseased superficial flexor tendons can be selectively excised, and the postoperative mobility of the affected fingers may not be impaired.

Trend and heterogeneity in forced vital capacity among Chinese students during 1985-2019: results from Chinese National Survey on Students' Constitution and Health.

BACKGROUND: Forced vital capacity (FVC) reflects respiratory health, but the long-term trend and heterogeneity in FVC of Chinese students were understudied. METHODS: Data were from Chinese National Survey on Students' Constitution and Health 1985-2019. Super Imposition by Translation and Rotation model was used to draw FVC growth curves. Sex-, region-, and nationality-heterogeneity in FVC was evaluated. Spearman correlation and generalized additive model was used to reveal influencing factors for FVC. RESULTS: Compared to 1985, age at peak FVC velocity was 1.09, 3.17, 0.74, and 1.87 years earlier for urban male, urban female, rural male, and rural female in 2019, respectively. Peak FVC velocity first decreased and then increased during 1985-2019, only male rebounded to larger than 1985 level. FVC declined from 1985 to 2005 and then raised. Males consistently had higher FVC than females, with disparities increasing in the 13-15 age group. Urban students also had higher FVC than rural students. In 2019, FVC difference between 30 Chinese provinces and the national average showed four scenarios: consistently above national average; less than national average until age 18, then above; greater than national average until age 18, then this advantage reversed; less than national average in almost all the age. Most Chinese ethnic minority students had lower FVC levels compared to Han students. Spearman correlation and generalized additive model showed that age, sex, and height were the leading influencing factors of FVC, followed by socioeconomic and environmental factors. CONCLUSIONS: Chinese students experienced advanced FVC spurt, and there was sex-, region- and nationality-heterogeneity in FVC. Routine measurement of FVC is necessary in less developed areas of China.

Calibration of a serum reference standard for Group B streptococcal polysaccharide conjugate vaccine development using surface plasmon resonance.

Group B streptococcus (GBS) is a leading cause of neonatal morbidity and mortality worldwide. Development of a maternal vaccine to protect newborns through placentally transferred antibody is considered feasible based on the well-established relationship between anti-GBS capsular polysaccharide (CPS) IgG levels at birth and reduced risk of neonatal invasive GBS. An accurately calibrated serum reference standard that can be used to measure anti-CPS concentrations is critical for estimation of protective antibody levels across serotypes and potential vaccine performance. For this, precise weight-based measurement of anti-CPS IgG in sera is required. Here, we report an improved approach for determining serum anti-CPS IgG levels using surface plasmon resonance with monoclonal antibody standards, coupled with a direct Luminex-based immunoassay. This technique was used to quantify serotype-specific anti-CPS IgG levels in a human serum reference pool derived from subjects immunized with an investigational six-valent GBS glycoconjugate vaccine.

DNMT1 and DNMT3B regulate tumorigenicity of human prostate cancer cells by controlling RAD9 expression through targeted methylation.

Prostate cancer is the second most common type of cancer and the second leading cause of cancer death in American men. RAD9 stabilizes the genome, but prostate cancer cells and tumors often have high quantities of the protein. Reduction of RAD9 level within prostate cancer cells decreases tumorigenicity of nude mouse xenographs and metastasis phenotypes in culture, indicating that RAD9 overproduction is essential for the disease. In prostate cancer DU145 cells, CpG hypermethylation in a transcription suppressor site of RAD9 intron 2 causes high-level gene expression. Herein, we demonstrate that DNA methyltransferases DNMT1 and DNMT3B are highly abundant in prostate cancer cells DU145, CWR22, LNCaP and PC-3; yet, these DNMTs bind primarily to the transcription suppressor in DU145, the only cells where methylation is critical for RAD9 regulation. For DU145 cells, DNMT1 or DNMT3B shRNA reduced RAD9 level and tumorigenicity, and RAD9 ectopic expression restored this latter activity in the DNMT knockdown cells. High levels of RAD9, DNMT1, DNMT3B and RAD9 transcription suppressor hypermethylation were significantly correlated in prostate tumors, and not in normal prostate tissues. Based on these results, we propose a novel model where RAD9 is regulated epigenetically by DNMT1 and DNMT3B, via targeted hypermethylation, and that consequent RAD9 overproduction promotes prostate tumorigenesis.

Release characteristics and mechanisms of sediment phosphorus in contaminated and uncontaminated rivers: A case study in South China.

Phosphorus (P) cycling present in sediments associated with iron (Fe), manganese (Mn) and sulfur (S) geochemical processes may cause secondary pollution in overlying water. Understanding the mechanisms of P release from sediments should help to restore water quality. This study used the diffusive gradients in thin film (DGT) technique to investigate the seasonal variation in the lability, remobilization mechanisms, and release characteristics of sediment P in the uncontaminated Xizhi River and the severely contaminated Danshui River, South China. P accumulation in sediments contributed to higher DGT-labile P concentrations in contaminated reaches, and the highest labile P concentrations were generally observed in summer season at each site. The significant positive relationships (p < 0.05) between labile Fe and P confirmed the Fe-P coupling release mechanism in uncontaminated sediments. Stronger relationships between labile Mn and P at contaminated sites indicated that Mn oxides played an important role in P remobilization. However, sulfate reduction associated with microbial activities (crucial genera: Desulfobulbus, Desulfomicrobium and Desulforhabdus) was considered to decouple the Fe & Mn-P cycling relationship, promoting P release at contaminated sites. The effluxes of sediment P were much higher in the Danshui River (mean 0.132 mg cm-2·d-1) than in the Xizhi River (mean 0.038 mg cm-2·d-1). And hot season led to growth in P effluxes that was much greater in contaminated river.

Quantifying the impacts of anthropogenic activity on chemical weathering based on source identification of hydrochemistry: the Liuxi river basin, southern China.

The impact of anthropogenic activity on chemical weathering is still an open and significant topic that requires clarification to improve the understanding of watershed evolution. We analyzed river water and rainwater samples to characterize the variation in hydrochemical characteristics and influencing factors. Samples were taken from the Liuxi River Basin (LRB), the only local drinking water supply for Guangzhou, and we studied geochemical parameters, major ions, and Si concentrations. Moreover, elemental ratios of end-members were determined and a modified-forward model was constructed to identify ion sources and estimate the chemical weathering rate (CWR) and anthropogenic input rate (AIR). Finally, we quantified the impacts of anthropogenic activity on the chemical weathering process. The results showed that the dominant hydrochemical type of river water was identified as HCO3-Ca, and rock weathering was the main contributor to river Na+, Mg2+, Ca2+ and HCO3-, whereas anthropogenic activity contributed the most to K+, Cl-, SO42-, and NO3-. The relatively high silicate weathering rate (SWR) (17.8-18.4 t per km2 per year) and AIR (37.8-60.3 t per km2 per year) were mainly attributed to erosion by nitric and sulfuric acid. The contribution rate of these acids to CWR could be regarded as a proxy quantifying the impact of anthropogenic activity on the chemical weathering process. This accounted for approximately 30% of the total SWR in the LRB. Our results demonstrate the effectiveness of hydrochemical source identification for quantifying the impacts of anthropogenic activity on chemical weathering.

Characteristics, Sources, and Risks of Polycyclic Aromatic Hydrocarbons in Topsoil and Surface Water from the Liuxi River Basin, South China.

The concentrations, composition, sources, and risks of polycyclic aromatic hydrocarbons (PAHs) in topsoil and surface water of the Liuxi River basin, south China were analyzed in this study. The total concentrations of 16 PAHs ranged from 296.26 to 888.14 ng/g in topsoil and from 156.73 to 422.03 ng/L in surface water, indicating mild pollution. The PAHs in topsoil exhibited an even spatial distribution, suggesting that they originated primarily from dry and wet deposition of transported pollutants. The concentration of PAHs in surface water did not differ significantly geographically, but the concentrations of total, three-, and four-ring PAHs were significantly lower in the Liuxi River than in its tributaries. Three- and two-ring PAHs predominated in topsoil and surface water, respectively. A correlation analysis suggested that the total organic carbon content and pH exerted a negligible effect on the spatial distribution of PAHs in topsoil, and they may have common sources. Fossil fuel combustion (particularly vehicle emissions) and coking production were the dominant sources of PAHs in topsoil, whereas those in surface water were derived from a variety of sources. The total toxic equivalent concentrations of 16 PAHs in topsoil ranged from 3.73 to 105.66 ng/g (mean, 30.93 ng/g), suggesting that exposure to the basin's topsoil does not pose a risk to the environment or public health according to the Canadian soil quality guidelines. A risk assessment revealed that the total PAH concentrations in surface water posed a low ecological risk.

Associations of lymphotoxin-a (LTA) rs909253 A/G gene polymorphism, plasma level and risk of ankylosing spondylitis in a Chinese Han population.

Lymphotoxin-a (LTA) may be associated with the pathogenesis of inflammatory diseases. To assess the association of the LTA rs909253 A/G polymorphism with plasma level and risk of ankylosing spondylitis (AS) in a Chinese Han population. Genotyping and LTA plasma were tested by mass spectroscopy and enzyme-linked immunosorbent assay (ELISA), respectively. The results showed that the average plasma level of LTA in AS was significantly lower than in the controls (P = 0.000). Our results also indicated that LTA rs909253 A/G was associated with a decreased risk of AS (G vs. A: P = 0.014). Significant differences were also found between the rs909253 A/G genotype and down-regulated plasma level in AS patients, compared with controls. After stratification analysis, a decreased risk of AS was associated with the LTA rs909253 G allele (G vs. A) among female patients, younger patients (Yr. < 30), HLA-B27-positive patients. In addition, In conclusion, LTA rs909253 A/G genotype has a significant relationship with decreased susceptibility to AS.

A new strategy for synthesizing silver doped mesoporous bioactive glass fibers and their bioactivity, antibacterial activity and drug loading performance.

A new strategy for preparing mesoporous metal-doped bioactive glass fibers (MBGFs) was designed, which included electrospinning and sulfonating mesoporous PS fibers, precipitating metal ions and bioactive glass sol-gel precursor into the mesoporous polystyrene (PS) fibers and calcinations. Silver-doped mesoporous BGFs (Ag-MBGFs) with a uniform diameter of 1-2 µm and a specific surface area of 40.22 m2 g-1 were prepared as an example and characterized by SEM, XRD, TG, ICP and FTIR. These Ag-MBGFs showed excellent bioactivity, antibacterial properties and drug loading and release performance due to their special mesoporous and fibrous structure. The concentration of Staphylococcus aureus decreased from 1 × 108 colony-forming units per mL (CFU mL-1) to 2.5 × 106 CFU mL-1 in 2 h and then to 2 × 102 CFU mL-1 in 12 h when the concentration of the Ag-MBGFs reached 16 mg mL-1. BGFs of different compositions and functions could be prepared by the same strategy in a mesoporous PS fiber template, which could enrich materials for constructing orthopedic implants.

SnSe2 Nanoparticles Chemically Embedded in a Carbon Shell for High-Rate Sodium-Ion Storage.

The development of advanced anode materials is crucial to enhance the performance of sodium-ion batteries (SIBs). In this study, SnSe2 nanoparticles chemically embedded in a carbon shell (SnSe2@C) were fabricated from Sn-organic frameworks and evaluated as an anode material for SIBs. The structural characterization demonstrated that there existed C-Sn chemical bonds between the SnSe2 nanoparticles and carbon shell, which could strongly anchor SnSe2 nanoparticles to the carbon shell. Such a structure can not only facilitate charge transfer but also ensure the structural stability of the SnSe2@C electrode. In addition, the carbon shell also helped in the dispersion of SnSe2 nanoparticles, thus offering more redox-active sites for Na+ storage. The as-prepared SnSe2@C nanocomposite could deliver good cycling stability and a superior rate capability of 324 mA h g-1 at 2 A g-1 for SIBs.

Remobilization mechanism and release characteristics of phosphorus in saline sediments from the Pearl River Estuary (PRE), South China, based on high-resolution measurements.

The internal loading of phosphorus (P) is commonly considered an essential factor contributing to eutrophication in freshwater bodies. However, investigation of the lability and remobilization characteristics of P in estuarine saline sediments has been limited. In this study, a sequential chemical extraction procedure and high-resolution measurement using the diffusive gradients in thin film (DGT) technique were employed to explore the lability, potential remobilization mechanism and release characteristics of sediment P in the Pearl River Estuary (PRE), South China. The P accumulated significantly in sediments along the west coast of the PRE due to the combined effects of terrestrial P inputs and specific hydrological conditions. The geochemical fractions of sediment P followed the order of organic P (Org-P) (mean: 58.6%) > iron-bound P (Fe-P) (23.4%) > calcium-bound P (Ca-P) (17.4%) > loosely bound P (LS-P) (0.63%). Synchronous vertical variations in DGT-labile Fe and P in the upper and middle parts of the sediment profiles confirmed that Fe-coupled P mobilization occurred in saline sediments. In contrast, sulfate reduction in bottom sediments supposed to decouple the Fe-P cycling relationship. Additionally, the formation of an "iron curtain" (Fe oxyhydroxides) in the oxic surface sediments efficiently prevented upward diffusion of P, leading to relatively low effluxes of P (0.098-6.59 ng cm-2 d-1) across the sediment-water interface.

Isolation of phytase-producing yeasts from rice seedlings for prospective probiotic applications.

The yeasts transmitted from seeds to sprouts might be used as probiotics for host plants. To investigate the inheritable yeasts of rice plants for probiotics, the fungal internal transcribed spacer (ITS) regions (ITS1 and ITS2) in rice sprouts were analyzed by Illumina-based sequencing. The fungal genera Candida, Mortierella, Alternaria, Penicillium, and Tomentella were revealed by both ITS1 and ITS2 sequence analysis. The endophytic yeasts were isolated from rice sprouts by yeast selective medium. Compared with the negative controls, inoculation of isolate Y3 released 2.2 folds higher concentration of free phosphate in soybean meal broth. Most of the phytase activities were located in the yeast cell interiors. The shoot lengths, shoot fresh weights, and root fresh weights of inoculated seedlings increased by 35%, 80%, and 60% compared with the control seedlings, respectively. The results suggested that the rice sprouts contained diverse phytase-producing yeasts transmitted from seeds. These yeasts might be adopted as prospective probiotics to improve rice growth by increasing phosphate utilization efficacy.

Engineering banana endosphere microbiome to improve Fusarium wilt resistance in banana.

BACKGROUND: Plant microbiome highlights the importance of endosphere microbiome for growth and health of the host plant. Microbial community analysis represents an elegant way to identify keystone microbial species that have a more central position in the community. The aim of this study was to access the interactions between the keystone bacterial species and plants during banana Fusarium wilt process, by comparing the endophytic bacterial and fungal community in banana roots and shoot tips during growth and wilting processes. The keystone bacterial species were isolated and further engineered to improve banana wilt resistance. RESULTS: Banana endosphere microbiome structure varied during plant growth and wilting processes. Bacterial and fungal diversity in the shoot tips and roots increased with the development of the banana plantlets. The bacterial groups belonging to the Enterobacteriaceae family with different relative abundances were detected in all the samples. The Klebsiella spp. might be the keystone bacteria during the growth of banana plantlets. The relative abundance of Fusarium associated with the wilt disease did not increase during the wilting process. The endophytic Enterobacteriaceae strains Enterobacter sp. E5, Kosakonia sp. S1, and Klebsiella sp. Kb were isolated on Enterobacteriaceae selective medium and further engineered by expressing 1-aminocyclopropane-1-carboxylate (ACC) deaminase on the bacterial cell walls (designated as E5P, S1P, and KbP, respectively). Pot experiments suggested that plants inoculated with strains E5, E5P, S1, and S1P increased resistance to the Fusarium wilt disease compared with the controls without inoculation, whereas the Klebsiella inoculation (Kb and KbP) did not increase the wilt resistance. Compared with the inoculation with the wild strains E5 and S1, the inoculation with engineered strains E5P and S1P significantly increased wilt resistance and promoted plant growth, respectively. The results illustrated that the keystone species in the banana microbiome may not be dominant in numbers and the functional role of keystone species should be involved in the wilt resistance. CONCLUSION: The ACC deaminase activity of engineered bacteria was essential to the Fusarium wilt resistance and growth promotion of banana plants. Engineering keystone bacteria in plant microbiome with ACC deaminase on the cell walls should be a promising method to improve plant growth and disease resistance.

Combined microbial and isotopic signature approach to identify nitrate sources and transformation processes in groundwater.

Nitrate (NO3-) pollution is a serious problem worldwide. Identification of NO3- sources and transformation processes in aquifers is a key step in effectively controlling and mitigating NO3- contamination. In this study, hydrochemical, microbial, and dual isotopic approaches were integrated to elucidate the sources and processes influencing NO3- contamination in the Pearl River Delta, China. The results showed a severe NO3- contamination, with 75% of the samples having NO3--N concentrations above the WHO standard of 10 mg L-1. The δ15NNO3- and δ18ONO3- values and a multivariate statistical analysis of hydrochemical data both revealed that manure and sewage were mainly responsible for NO3- contamination. Biological indicators further demonstrated that, manure and sewage had greater impacts on groundwater quality during the rainy season than during the dry season. Based on the significant relationships of δ15NNO3- and δ18ONO3- with the logarithmic NO3- concentration (Ln(NO3-)), denitrification was confirmed to occur in the discharge zone during the rainy season. Proteobacteria, Bacteroidetes, and Planctomycetes were identified as the dominant phyla, and Dechloromonas, Flavobacterium, and Nitrospira were dominant among the denitrifying bacteria in groundwater. The abundance of denitrifying bacteria had significant positive correlations with δ15NNO3- and NO2--N during the rainy season, further confirming the occurrence of denitrification during the rainy season. This study showed that dual isotope techniques combined with microbial data can be a powerful tool for identifying the sources and microbial processes affecting NO3- in groundwater. Moreover, the results can provide useful insights for environmental managers to verify groundwater pollution and better apply remediation solutions.

Seasonal characteristics of chemical compositions and sources identification of PM2.5 in Zhuhai, China.

Fine particulate matter is associated with adverse health effects, but exactly which characteristics of PM2.5 are responsible for this is still widely debated. We evaluated seasonal dynamics of the composition and chemical characteristics of PM2.5 in Zhuhai, China. PM2.5 characteristics at five selected sites within Zhuhai city were analyzed. Sampling began on January 10, 2015, and was conducted for 1 year. The ambient mass concentration, carbon content (organic and elemental carbon, OC and EC), level of inorganic ions, and major chemical composition of PM2.5 were also determined. Average concentrations of PM2.5 were lower than the National Ambient Air Quality Standard (NAAQS) 24-h average of 65 µg/m3. The daily PM2.5 concentration in Zhuhai city exhibited clear seasonal dynamics, with higher daily PM2.5 concentrations in autumn and winter than in spring and summer. Carbon species (OC and EC) and water-soluble ions were the primary components of the PM2.5 fraction of particles. Apart from OC and EC, chemical species in PM2.5 were mainly composed of NH4+ and SO42-. There was a marked difference between the summer and winter periods: the concentrations of OC and EC in winter were roughly 3.4 and 4.0 times than those in summer, while NH4+, SO42-, NO3-, and Na+ were 3.2, 4.5, 28.0, and 5.7 times higher in winter than those in summer, respectively. The results of chemical analysis were consistent with three sources dominating PM2.5: coal combustion, biomass burning, and vehicle exhaust; road dust and construction; and from reaction of HCl and HNO3 with NH3 to form NH4Cl and NH4NO3. However, additional work is needed to improve the mass balance and to obtain the source profiles necessary to use these data for source apportionment.

Uptake of Cd(II) Onto Raw Crab Shells: Isotherm, Kinetic, Adsorption Properties And Mechanisms.

This study focuses on the uptake of cadmium (Cd(II)) ion from water onto raw crab shells acting as a biosorbent. Experimental data were perfectly fitted to the Langmuir and Dubinin-Radushkevich models, while the uptake kinetics are well-described using the pseudo-second-order model. The effects of experimental conditions on the uptake isotherms and kinetics are discussed in detail. A study of uptake thermodynamics has indicated that the Cd(II) uptake onto the crab shell is an endothermic and spontaneous process. For further understanding of this process, possible mechanisms of Cd(II) uptake onto crab shell have been deduced from experimental results. Desorption experiment shows that 93.7% of adsorbed Cd(II) could be recovered with a 0.1 M HNO3 solution. The inhibitory effects of other metal co-ions on the Cd(II) uptake on the crab shell are also discussed.

A gelatin composite scaffold strengthened by drug-loaded halloysite nanotubes.

Mechanical properties and anti-infection are two of the most concerned issues for artificial bone grafting materials. Bone regeneration porous scaffolds with sustained drug release were developed by freeze-drying the mixture of nanosized drug-loaded halloysite nanotubes (HNTs) and gelatin. The scaffolds showed porous structure and excellent biocompatibility. The mechanical properties of the obtained composite scaffolds were enhanced significantly by HNTs to >300%, comparing to those of gelatin scaffold, and match to those of natural cancellous bones. The ibuprofen-loaded HNTs incorporated in the scaffolds allowed extended drug release over 100h, comparing to 8h when directly mixed the drug into the gelatin scaffold. The biological properties of the composite scaffolds were investigated by culturing MG63 cells on them. The HNTs/gelatin scaffolds with excellent mechanical properties and sustained drug release could be a promising artificial bone grating material.

Synthesis of nanosized 58S bioactive glass particles by a three-dimensional ordered macroporous carbon template.

Nanosized 58S bioactive glass (BG) particles were synthesized by using a three-dimensional ordered macroporous carbon template (OMC) with a pore size of 400nm. The obtained 58S BG particles possessed a diameter of 300nm, narrow size distribution and uniform spherical morphology. 58S/gelatin composites were prepared and showed much better mechanical properties than pure gelatin. The narrow size distribution of the 58S particles replicated from OMC was confirmed crucial to the mechanical properties of the 58S/gelatin composite, comparing to the contrast sample prepared with polydispersed particles. The outstanding bioactivity of the 58S BG particles was confirmed by inducing the formation of carbonated hydroxyapatite on the 58S/gelatin composite surface. This work showed a successful example that OMC template could be used to synthesize particles requiring a robust reaction condition, and a particle synthesis method that could well control particle size distribution was important for preparing materials with outstanding mechanical properties.