Comparison of falls and risk factors among older adults in urban villages, urban and rural areas of Shantou, China.

Objective: To investigate and compare the differences between the incidence of falls, balance and living environment among older persons in urban villages and other types of residential areas. Methods: We surveyed 580 older adults living in different types of residential areas in Shantou, China, surveying basic information, fall incidence, balance ability testing of older persons, home environment safety assessment. Results: The incidence of falls among older people in urban villages (19.54 %) was between urban areas(26.63 %) and rural areas(16.91 %). The influencing factors of falls in different residential types were different. Near-fall, abnormal bowel movement, and impaired balance ability were the risk factors of falls among older persons in urban villages. Divorce/single, fair and poor hearing loss and near-fall were the risk factors of falls in urban older adults. Frailty and impaired balance ability were the risk factors of falls in rural older people. Conclusions: Risk factors for falls in older people vary according to the characteristics of their living areas and relevant interventions should be targeted according to the characteristics of falls occurring in different residential areas.

Simulated sunlight/periodate-triggered formation of toxic halogenated bisphenols in highly saline water.

Periodate (PI)-based oxidation using the activators, such as metal ions and light irradiation, has emerged as a feasible treatment strategy for the effective remediation of contaminated water and wastewater. Given the pervasive nature of PI residues and solar exposure during application, the role of solar light in remediating the challenging highly saline water matrices needs to be elucidated. In this study, bisphenol A (BPA) was selected as the targeted micropollutant, which can be efficiently eliminated by the simulated sunlight (SSL)/PI system in the presence of high-level Cl- (up to 846.0 mM) at pH 7.0. The presence of different background constituents of water, such as halides, nitrate, and dissolved organic matter, had no effect, or even accelerated BPA abatement. Particularly, the ubiquitous Br- or I- appreciably enhanced the BPA transformation efficiency, which may be ascribed to the generation of high-selective reactive HOBr or HOI. The in silico predictions suggested that the transformation products generated by halide-mediated SSL/PI systems via halogen substitutions showed greater persistence, bioaccumulation, and aquatic toxicity than BPA itself. These findings highlighted a widespread phenomenon during PI-based oxidative treatment of highly saline water, which needs special attention under solar light illumination.

[Comparison of talonavicular-cuneiform joint fusion with bone grafting and without bone grafting in treatment of Müller-Weiss disease].

Objective: To compare the effectiveness of talonavicular-cuneiform joint fusion with iliac bone grafting and without bone grafting in the treatment of Müller-Weiss diseases (MWD). Methods: The clinical data of 44 patients (44 feet) with MWD who received talonavicular-cuneiform joint fusion between January 2017 and November 2022 and met the selection criteria was retrospectively analyzed. Among them, 25 patients were treated with structural iliac bone grafting (bone grafting group) and 19 patients without bone grafting (non-bone grafting group). There was no significant difference ( P>0.05) in age, gender composition, body mass index, disease duration, affected side, Maceira stage, and preoperative American Orthopaedic Foot and Ankle Society (AOFAS) score, visual analogue scale (VAS) score, anteroposterior/lateral Meary angle, and Pitch angle between the two groups. Operation time, operation cost, and postoperative complications were recorded in the two groups. AOFAS and VAS scores were used to evaluate the function and pain degree of the affected foot. Meary angle and Pitch angle were measured on the X-ray film, and the joint fusion was observed after operation. The difference (change value) of the above indexes before and after operation was calculated for comparison between groups to evaluate the difference in effectiveness. Results: The operation was successfully completed in both groups, and the incisions in the two groups healed by first intention. The operation time and cost in the bone grafting group were significantly more than those in the non-bone grafting group ( P<0.05). All patients were followed up. The median follow-up time was 41.0 months (range, 16-77 months) in the non-bone grafting group and 40.0 months (range, 16-80 months) in the bone grafting group. There was skin numbness of the medial dorsalis of the foot in 1 case, internal fixation stimulation in 2 cases, and pain at the iliac bone harvesting area in 1 case of the bone grafting group. There was skin numbness of the medial dorsalis of the foot in 1 case and muscle atrophy of the lower limb in 1 case of the non-bone grafting group. There was no significant difference in the incidence of complications between the two groups ( P>0.05). At last follow-up, the AOFAS scores of the two groups significantly improved when compared with those before operation, while the VAS scores significantly decreased, the anteroposterior/lateral Meary angle and Pitch angle significantly improved, and the differences were significant ( P<0.05). There was no significant difference in the change values of outcome indicators between the two groups ( P>0.05). There was no delayed bone union or bone nonunion in both groups, and joint fusion was achieved at last follow-up. Conclusion: In the treatment of MWD, there is no significant difference in effectiveness and imaging improvement of talonavicular-cuneiform joint fusion combined with or without bone grafting. However, non-bone grafting can shorten the operation time, reduce the cost, and may avoid the complications of bone donor site.

Fe(IV)/Fe(V)-mediated polyferric sulfate/periodate system: A novel coagulant/oxidant strategy in promoting micropollutant abatement.

Strategic modulation of the advanced oxidation processes for the selective oxidation of micropollutants has attracted accumulating attention in water decontamination. This study first reported the combination of the coagulant polyferric sulfate (PFS) and oxidant periodate (PI) to accomplish synergistic abatement of the antibiotic sulfamethoxazole (SMX). The oxidizing performance of SMX by this system was almost unaffected by coexisting water constituents, indicating the great promise of selective oxidation. Different from the current hydroxyl radicals (•OH)-mediated coagulant/oxidant systems (e.g., PFS/H2O2 and PFS/ozone), the dominance of high-valent Fe(IV)/Fe(V) intermediates was unambiguously verified in the PFS/PI treatment. The PFS colloids before and after the oxidation were characterized and the iron speciation was analyzed. The transformation of monomeric iron configurations (Fe(a)) to oligomeric iron configurations (Fe(b)) could maintain the homeostasis of surface-bound Fe(III) and Fe(II). The interaction mechanisms included the production of reactive species and dynamic reaction equilibrium for micropollutant degradation. Finally, the transformation pathways of SMX and carbamazepine (CMZ) in the PFS/PI system were postulated. Overall, this study provided a novel coagulant/oxidant strategy to achieve selective and sustainable water purification.

Comparative efficacy of vancomycin in treating ST5 and ST764 methicillin-resistant Staphylococcus aureus infections in adult patients.

IMPORTANCE: Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium that is resistant to multiple drugs and can cause serious infections. In recent years, one of the most widespread strains of MRSA worldwide has been the clonal complex 5 (CC5) type. Sequence type 5 (ST5) and ST764 are two prevalent CC5 strains. Although ST5 and ST764 are genotypically identical, ST764 is classified as a hybrid variant of ST5 with characteristics of community-associated MRSA (CA-MRSA). In contrast to ST5, ST764 lacks the tst and sec genes but carries the staphylococcal enterotoxin B (seb) gene. Vancomycin is commonly used as the first-line treatment for MRSA infections. However, it is currently unclear whether the genetic differences between the ST5 and ST764 strains have any impact on the efficacy of vancomycin in treating MRSA infections. We conducted a prospective observational study comparing the efficacy of vancomycin against ST5-MRSA and ST764-MRSA in five hospitals in China. There were significant differences in bacteriological efficacy between the two groups, with virulence genes, such as the tst gene, being a risk factor for bacterial persistence (adjusted odds ratio, 4.509; 95% confidence interval, 1.216 to 16.724; P = 0.024). In the future, it may be necessary to consider personalized vancomycin treatment strategies based on the genetic characteristics of MRSA isolates.

Solar/periodate-triggered rapid inactivation of Microcystis aeruginosa by interrupting the Calvin-Benson cycle.

Frequent outbreak of cyanobacteria is a serious problem for drinking water treatment. The microcystins released from Microcystis aeruginosa (M. aeruginosa) could cause irreversible damage to human health. Catalyst-free solar/periodate (PI) system has recently presented great potential for bacterial inactivation, whereas the application potential and underlying mechanisms of the effective M. aeruginosa control remain unclear. Our work delineated the key role of ROS that inactivating/harmless disposing M. aeruginosa in the simulated sunlight (SSL)/PI system. Singlet oxygen may specifically cause DNA damage but maintain membrane integrity, preventing the risk of microcystins leakage. The SSL/PI 300 µM system could also effectively inhibit M. aeruginosa recovery for >7 days and completely degrade microcystin-LR (50.0 µg/L) within 30 min. Non-targeted metabolomic analysis suggested that the SSL/PI system inactivated M. aeruginosa mainly by interrupting the Calvin-Benson cycle, which damaged the metabolic flux of glycolysis and its downstream pathways such as the oxidative PPP pathway and glutathione metabolism. Furthermore, the activated PI system exhibited an even better algal inhibition under natural sunlight irradiation, evidenced by the seriously damaged cell membrane of M. aeruginosa. Overall, this study reported the comprehensive mechanisms of algal control and application potentials of solar/PI systems. The findings facilitated the development of emerging algicidal technology and its application in controlling environmental harmful algae.

Geriatric drug trials on solid tumor are scarce worldwide.

Background: Conducting geriatric trials is the most feasible way to address the vast underrepresentation of older adults in clinical trials of cancer therapies. This study is a globally comprehensive examination of geriatric trials for solid tumor worldwide over the last decade. Methods: Up-to-date information on cancer drug trials in older adults aged over 59 years from the beginning of 2012 to the end of 2021 was collected from Trialtrove and Pharmaprojects. The number of identified trials was the dependent variable and corresponding analysis was conducted from the perspective of time trend, status quo and comparisons by region and country, sponsor type and cancer type, study status and phase. Results: A total of 292 geriatric cancer drug trials were identified, of which 287 were single-region studies, 219 were initiated by academic groups, and 55 (18.8%) were terminated. Decreasing trends in the annual number of all trials (-9.2% per year) and the annual number of trials by academic groups (-9.4%) were observed over time. Of the geriatric trials, 183 were conducted in Asia; this number was significantly higher than that in Europe (74), North America (37), Oceania (4), and South America (1). Similar difference was found in participation rate in trials by academic groups ranging from 71.7% in Asia to 0.5% in South America. Of the trials, 19 and 97 were initiated before drug and indication approval, respectively, and the remaining 176 were initiated after indication approval. Phase II trials accounted for the highest proportion of trials (213, 72.9%), while phase I trials accounted for the lowest proportion (14, 4.8%). Trials by academic groups had a higher termination rate (21.5% vs. 11.0%) and fewer were phase IV trials (8.2% vs. 21.9%). Treatment was explored for 16 different cancers, with lung, colorectal and breast cancers being the most common. Conclusion: Geriatric trials of solid tumor drugs are scarce and partially prematurely terminated. Moreover, the number of geriatric trials has decreased and differs according to region. Global guidance and regulatory supervision are needed to facilitate the acquisition of adequate evidence on drug risk-benefit profiles in older adults, and thus to achieve high-quality care and safe medication.

Uncovering novel disinfection mechanisms of solar light/periodate system: The dominance of singlet oxygen and metabolomic insights.

Disinfection plays an essential role in waterborne pathogen control and disease prevention, especially during the COVID-19 pandemic. Catalyst-free solar light/periodate (PI) system has recently presented great potential in water disinfection, whereas the in-depth chemical and microbiological mechanisms for efficient bacterial inactivation remain unclear. Our work delineated firstly the critical role of singlet oxygen, instead of reported hydroxyl radicals and superoxide radicals, in dominating bacterial inactivation by the PI/simulated sunlight (SSL) system. Multi-evidence demonstrated the prominent disinfection performance of this system for Staphylococcus aureus in terms of culturability (> 6 logs CFU), cellular integrity, and metabolic activity. Particularly, the excellent intracellular DNA removal (> 95%) indicated that PI/SSL system may function as a selective disinfection strategy to diminish bacterial culturability without damaging the cell membrane. The PI/SSL system could also effectively inhibit bacterial regrowth for > 5 days and horizontal gene transfer between E. coli genera. Nontargeted metabolomic analysis suggested that PI/SSL system inactivated bacteria by triggering the accumulation of intracellular reactive oxygen species and the depletion of reduced glutathione. Additionally, the PI/SSL system could accomplish simultaneous micropollutant removal and bacterial inactivation, suggesting its versatility in water decontamination. Overall, this study deciphers more comprehensive antibacterial mechanisms of this environmentally friendly disinfection system, facilitating the technical development and application of the selective disinfection strategy in environmental pathogen control.

Promoting selective water decontamination via boosting activation of periodate by nanostructured Ru-supported Co3O4 catalysts.

The superior catalytic efficiency of ruthenium (Ru)-based nanocomposites in advanced oxidation processes for water decontamination has attracted accumulating attention worldwide. However, rather limited knowledge is currently available regarding their roles in activating periodate (PI), an emerging oxidant with versatile environmental applications. This study firstly delineated that Ru-supported Co3O4 (Ru/Co3O4), a typical Ru-based nanomaterial, can efficiently accomplish PI activation to eliminate multiple organic micropollutants and inactivate different pathogenic bacteria. Almost all eight micropollutants can be completely removed within 2 min of Ru/Co3O4-PI oxidation except sulfamethoxazole (SMX), which was degraded ∼70 % at 2 min with 100 % mineralization after 10 min. The excellent catalytic performance was independent of PI dosages, initial pH, and coexisting water constituents, demonstrating its prominent capability as a selective oxidation strategy. Diverse lines of evidence indicated the dominant role of single oxygen in the Ru/Co3O4-PI system, which triggered the generation of five transformation products of SMX with reduced environmental risks. Concurrently, PI was stoichiometrically converted to the eco-friendly IO3-. Additionally, Ru/Co3O4-PI system achieved 6-log inactivation of different pathogenic bacteria within 1 min, implying the feasibility of rapid water disinfection. Overall, this work demonstrated the excellent promise of Ru-based composites in PI activation for highly efficient and selective water decontamination.

Emerging periodate-based oxidation technologies for water decontamination: A state-of-the-art mechanistic review and future perspectives.

With the ever-increasing severity of the ongoing water crisis, it is of great significance to develop efficient, eco-friendly water treatment technologies. As an emerging oxidant in the advanced oxidation processes (AOPs), periodate (PI) has received worldwide attention owing to the advantages of superior stability, susceptible activation capability, and high efficiency for decontamination. This is the first review that conducts a comprehensive analysis of the mechanism, pollutant transformation pathway, toxicity evolution, barriers, and future directions of PI-based AOPs based on the scientific information and experimental data reported in recent years. The pollutant elimination in PI-based AOPs was mainly attributed to the in situ generate reactive oxygen species (e.g., •OH, O(3P), 1O2, and O2•-), reactive iodine species (e.g., IO3• and IO4•), and high-valent metal-oxo species with exceptionally high reactivity. These reactive species were derived from the PI activated by the external energy, metal activators, alkaline, freezing, hydroxylamine, H2O2, etc. It is noteworthy that direct electron transport could also dominate the decontamination in carbon-based catalyst/PI systems. Furthermore, PI was transformed to iodate (IO3-) stoichiometrically via an oxygen-atom transfer process in most PI-based AOPs systems. However, the production of I2, I-, and HOI was sometimes inevitable. Furthermore, the transformation pathway of typical micropollutants was clarified, and the in silico QSAR-based prediction results indicated that most transformation products retained biodegradation recalcitrance and multi-endpoint toxicity. The barriers faced by the PI-based AOPs were also clarified with potential solutions. Finally, future perspectives and research directions are highlighted based on the current state of PI-based AOPs. This review enhances our in-depth understanding of PI-based AOPs for pollutant elimination and identifies future research needs to focus on the reduction of toxic byproducts.

Removal of chloramphenicol antibiotics in natural and engineered water systems: Review of reaction mechanisms and product toxicity.

Chloramphenicol antibiotics are widely applied in human and veterinary medicine. They experience natural attenuation and/or chemical degradation during oxidative water treatment. However, the environmental risks posed by the transformation products of such organic contaminants remain largely unknown from the literature. As such, this review aims to summarize and analyze the elimination efficiency, reaction mechanisms, and resulting product risks of three typical chloramphenicol antibiotics (chloramphenicol, thiamphenicol, and florfenicol) from these transformation processes. The obtained results suggest that limited attenuation of these micropollutants is observed during hydrolysis, biodegradation, and photolysis. Comparatively, prominent abatement of these compounds is accomplished using advanced oxidation processes; however, efficient mineralization is still difficult given the formation of recalcitrant products. The in silico prediction on the multi-endpoint toxicity and biodegradability of different products is systematically performed. Most of the transformation products are estimated with acute and chronic aquatic toxicity, genotoxicity, and developmental toxicity. Furthermore, the overall reaction mechanisms of these contaminants induced by multiple oxidizing species are revealed. Overall, this review unveils the non-overlooked and serious secondary risks and biodegradability recalcitrance of the degradation products of chloramphenicol antibiotics using a combined experimental and theoretical method. Strategic improvements of current treatment technologies are strongly recommended for complete water decontamination.

A Reference-Scaled Average Bioequivalence Study of Azithromycin Tablets Manufactured in China and the United States: An Open-Label, Randomized, Single-Dose, 3-Way Crossover Study in Healthy Chinese Subjects Under Fasted and Fed Conditions.

Azithromycin (Zithromax) is an azalide antibiotic that binds to the 50S ribosomal subunit of the susceptible organism and thereby interferes with its protein synthesis. An open-label, randomized, single-dose, 3-way crossover bioequivalence study was conducted to compare the rate and extent of absorption of the azithromycin 250-mg tablet manufactured at Pfizer Dalian (China) and that at Pfizer Barceloneta (United States) under fasted and fed conditions in healthy Chinese subjects. This study aimed to support a generic consistency evaluation program, initiated by the National Medical Products Administration, for evaluating the quality and efficacy of the products manufactured in China. In the study, the within-subject standard deviation for area under the serum concentration-time profile from time 0 to 72 hours after dosing in the fasted condition was <0.294, and the 90%CI for the ratio was within 80% to 125%; the within-subject SDs for serum peak concentration in the fasted condition, area under the serum concentration-time profile from time 0 to 72 hours after dosing in the fed condition, and serum peak concentration in the fed condition, were all >0.294, with the upper confidence bounds being <0.00, and the point estimates of the ratios being within 80% to 125%. The results support the bioequivalence between azithromycin tablets manufactured in China and the United States in fasted and fed conditions, with both tablets showing an acceptable safety/tolerability profile in the studied population.

Lorlatinib for Previously Treated ALK-Positive Advanced NSCLC: Primary Efficacy and Safety From a Phase 2 Study in People's Republic of China.

INTRODUCTION: Lorlatinib was found to have activity in ALK-positive NSCLC in a global phase 1 and 2 study. We report an ongoing phase 2 study in Chinese patients with ALK-positive advanced or metastatic NSCLC. METHODS: Open-label, dual-cohort study (NCT03909971); patients had progressive disease after ALK tyrosine kinase inhibitor treatment (cohort 1: previous crizotinib; cohort 2: one ALK tyrosine kinase inhibitor other than crizotinib [±prior crizotinib]), more than or equal to one unirradiated extracranial target lesion, and Eastern Cooperative Oncology Group performance status of 0 to 2. Patients received oral lorlatinib 100 mg once daily in continuous 21-day cycles. Primary end point: objective response in cohort 1 by independent central radiology (ICR) according to Response Evaluation Criteria in Solid Tumors version 1.1. Analyses were based on patients receiving more than or equal to one dose. RESULTS: At data cutoff (August 10, 2020), 109 patients were enrolled (cohort 1: n = 67; cohort 2: n = 42). A total of 47 patients in cohort 1 (70.1%, 95% confidence interval [CI]: 57.7-80.7, p < 0.0001; primary end point) and 20 patients in cohort 2 (47.6%, 95% CI: 32.0-63.6, secondary end point) achieved objective response by ICR. Median progression-free survival was not reached in cohort 1 and was 5.6 months in cohort 2. In patients with brain lesions at baseline, 29 of 36 patients in cohort 1 (80.6%, 95% CI: 64.0-91.8) and 10 of 21 patients in cohort 2 (47.6%, 95% CI: 25.7-70.2) achieved objective intracranial response by ICR. Hypercholesterolemia (92.7%) and hypertriglyceridemia (90.8%) (cluster terms) were common treatment-related adverse events (TRAEs). Nine patients (8.3%) had serious TRAEs; one permanently discontinued from treatment because of TRAEs. CONCLUSIONS: Lorlatinib was found to have a robust and durable response and high intracranial objective response in previously treated Chinese patients with ALK-positive NSCLC.

The mortality trends of falls among the elderly adults in the mainland of China, 2013-2020: A population-based study through the National Disease Surveillance Points system.

Background: Fall in elderly is a major public health problem. Characterizing trends in fall mortality in different subpopulations could help identifying the needs and developing preventive program for target groups. Here we evaluated the trends of fall-related deaths in Chinese mainland among adults aged ≥60 years specific in sex, age, and provinces, to measure the change in this mortality rate between 2013 and 2020, and to explore the underlying factors influencing this change. Methods: Mortality data were retrieved from the National Disease Surveillance Points system(DSPs) of China, a national-level and provincial-level representative data source, to estimate the impact of elderly falls on mortality in the mainland of China and the specific provinces from 2013 to 2020. The joinpoint regression model was used to estimate the temporal trend of mortality in elderly fallen by calculating the annual percentage change (APC). Findings: The age-standardized falls mortality was 10·438 per 100 000 in 2020. The age-standardized mortality of elderly falls in total and female showed a steady increasing trend (APC=1·96%, p = 0·023 total; APC=3·42%, p = 0·003 female), with it was stable in males (APC=1.26%, p>0·05). Fall mortality among the elderly was more common in people over 70 years of age and increased sharply. The death rates and APCs were highest among the oldest age groups(aged≥85 years). The higher fall mortality was mainly focused in the southeast and central regions, and lower rates were in the northeast provinces and Tibet. Interpretation: Since 2013, the overall fall-related mortality trend among individuals aged ≥60 years has been consistently increasing in China, making it most critical public health challenge. Adherence interventions and increased social support for those at most risk should be considered. Funding: None.

A longitudinal study on psychological burden of medical students during COVID-19 outbreak and remission period in China.

BACKGROUND AND OBJECTIVES: Due to their professional characteristics and future career orientation, medical students have a deeper understanding of COVID-19 and enact disease prevention and control measures, which may cause psychological burden. We aimed to assess the psychological impact during the COVID-19 outbreak period(OP) and remission period(RP) among medical students. METHODS: We surveyed the medical students in Shantou University Medical College twice-during the OP and the RP, surveying psychological burden of COVID-19 lockdowns and its associated factors. 1069 respondents were recruited in OP and 1511 participants were recruited in RP. We constructed nomograms to predict the risk of psychological burden using risk factors that were screened through univariate analysis of the surveyed data set. RESULTS: There was a statistically significant longitudinal increment in psychological burden from OP to RP, and stress as well as cognition in psychological distress were the most dominant ones. Common impact factors of the depression, anxiety and stress included frequency of outdoor activities, mask-wearing adherence, self-perceived unhealthy status and exposure to COVID-19. In addition, the high frequency of handwashing was a protective factor for depression and anxiety. The C-index was 0.67, 0.74 and 0.72 for depression, anxiety and stress, respectively. CONCLUSION: The psychological impact of COVID-19 was worse during the RP than during the OP. Thus, it's necessary to continue to emphasize the importance of mental health in medical students during the pandemic and our proposed nomograms can be useful tools for screening high-risk groups for psychological burden risk in medical students.

Psychological Burden and Experiences Following Exposure to COVID-19: A Qualitative and Quantitative Study of Chinese Medical Student Volunteers.

Background: During the COVID-19 pandemic, some medical students devoted themselves to volunteer activities, but it was the first time that they had been exposed to such an infectious disease and they might have experienced fear in the face of the epidemic. We aimed to conduct a timely assessment of the psychological burden and experience on medical student volunteers during the COVID-19 pandemic. Methods: We used the 21-item Depression Anxiety Stress Scales to survey the psychology burden of students in April 2020. Semi-structured interviews were conducted with nine medical students who signed up for volunteer activities in Chinese from February to April 2020. Quantitative and qualitative methods were used to analyze the data. Results: The detection of depression, anxiety and stress of medical student volunteers were 26.8%, 20.2% and 11.1%, respectively. The volunteer's negative emotions were more pronounced before work and diminished gradually. Most participants expressed no concern about being infected themselves, but worry about family infection. Participant's motivations for volunteering were primarily their duties as medical students and encouragement from their families/teachers. The vast majority of medical students said they would be willing to work as medical assistants again and this experience would not affect their career choice. Conclusions: Chinese medical student volunteers tended to show negative emotions at the beginning of their work, and then gradually declined, while positive emotions emerged. Most medical students were willing to volunteer as medical assistants when their country needed them due to their sense of responsibility as medical students. This study on the psychological and experiential aspects were derived from Chinese medical student volunteers and might have a significant impact on future public health emergencies in similar settings.

Influence of chemical treatment and drying method on the properties of cellulose fibers of luffa sponge.

The exploration of modified luffa sponge (LS) cellulose fiber in the field of polymer composite can contribute to the development of high-performance and lightweight composites. In this study, two chemical treatments (10%NaOH-20%CH3COOH (Method 1) and 10%NaOH-5%Na2SO3 (Method 2)) and two drying methods (air drying and freeze-drying) were used to treat LS. The microscopic characteristics and physical properties showed that Methods 1 and 2 caused shrinkage of the LS fibers and increased their fiber density by 30.6% and 15.0%. Meanwhile, freeze-drying kept the cells of modified LS fibers full and decreased their fiber density by 5.0% and 21.0%, respectively. The tensile properties test analyses indicated that freeze-drying further increased the elongation at break values of modified LS fibers by 25.3% and 17.7%, respectively. The moisture absorption analyses showed that freeze-drying could further decrease the moisture absorption ratios of modified LS fibers by 25.8% and 35.8%, respectively, which was useful for improving the dimensional stability of composite materials. Moreover, the thermogravimetric analysis reveals that freeze-drying increased onset degradation temperatures of the modified fibers by 24.0 °C and 6.7 °C, which was beneficial to improve the thermal stability of the composite material.

A novel bamboo sheet chair and its influence on sitting comfort.

BACKGROUND: In today's economy, workers spend increasingly more time in seated positions, leading to a growing scientific interest in chair design. In this study we used body pressure distribution tests to compare a novel bamboo chair with unique structural features to other commonly-used chairs. We studied the bamboo sheet chair's physical characteristics and comfort to provide a scientific theoretical basis for common use seat design. METHODS: A total of 25 (14 male and 11 female) subjects participated in the study. Subjects were divided into six groups according to their body characteristics parameters included stature, weight, shoulder breadth, hip breadth, waist width, popliteal height, buttocks-popliteal length, and buttock-abdomen depth, with three groups for males and three groups for females. Each subject was required to complete specified body pressure tests for three different experimental chairs for three minutes and subjective comfort evaluations were also administered. The pressure indexes were measured from the seat pan and backrest and calculated with MATLAB 2015b, which mainly included maximum pressure (Pm), average pressure (Pa), pressure exponent (Pe) and contact area index (P AI ). Three pressure threshold limits of 0.67 kPa, 4.00 kPa and 9.33 kPa and four contact surface indexes were used in the experiment to reflect the contact area between human and chair. RESULTS: The contact areas in the backrest (52.96 ± 32.94 cm2) and seat pan (307.75 ± 90.31 cm2) in the middle-to-high threshold pressure range, and the contact areas of the backrest (4.34 ± 5.95 cm2) in the high threshold pressure range of bamboo sheet chair were smaller than the corresponding indexes of the common office chair (81.430 ± 45.04 cm2, p = 0.00; 394.39 ± 98.99 cm2, p = 0.02; 13.54 ± 12.00 cm2, p = 0.00, respectively). The pressure index (2.68 ± 0.88 kPa), maximum pressure (6.66 ± 2.05 kPa), and average pressure (2.42 ± 0.59 kPa) values of the bamboo sheet chair backrest were also found to be lower than those of the office chair (4.32 ± 1.62 kPa, p = 0.00; 10.50 ± 3.88 kPa, p = 0.00; 3.43 ± 0.97 kPa, p = 0.00, respectively). The average pressure on the seat pan was greater than 4 kPa for all subjects, while the average pressure on the seat pan was greater than 9.33 kPa for male subjects with a body mass index (BMI) of 27.48. DISCUSSION: The bamboo sheet chair's contact areas within the middle-to-high and high-pressure threshold ranges of the backrest and seat pan were smaller than those of the office chair, indicating that the bamboo sheet chair is effective at relieving pressure. Human body characteristics must be considered in the design of seat functional size. Buttocks-popliteal length, weight, body mass index, body shape and weight distribution, all have important effects on the distribution of body pressure at the human-chair interface.

Effect of Chemical Treatments on the Properties of High-Density Luffa Mattress Filling Materials.

Luffa is a lightweight porous material with excellent biocompatibility and abundant resources. In this paper, three kinds of softening treatment methods, alkali-hydrogen peroxide (Method 1), alkali-acetic acid (Method 2), and alkali-urea (Method 3), were used to soften high-density (HD) cylindrical luffa (CL) mattress-filling materials (MFM). Microscopic observation, mechanical performance testing and other analyses were performed to evaluate the effects of the three kinds of softening methods on the wettability, compression resilience and support performance of CL MFM. The results showed that: (1) After the treatment by Method 1, Method 2 and Method 3, the peak stress of CL decreased by 73%, 10% and 27%, respectively. In addition, after three kinds of softening treatments, the uniformity of CL increased. (2) When the CL MFM of high density rank treated by Method 1 was compressed by 40%, the firmness values of the surface, core and bottom reduced by 53.49% 40.72%, and 46.17%, respectively, compared to that of untreated CL. In addition, for the CL MFM of high density rank treated by Method 3 and then compressed to 60%, the firmness of the surface layer, core layer and bottom layer reduced by 41.2%, 33.7%, and 36.9%, respectively. (3) The contact angle of luffa treated by Method 3 was the smallest, next came Method 1 and Method 2, and untreated was the largest. (4) After the treatment by Method 3, the fiber bundle of luffa was intact, and the compression resilience of the CL was obviously increased. Therefore, this method can effectively reduce the firmness of MFM and also improve the uniformity and wettability of CL.

Properties of Two-Variety Natural Luffa Sponge Columns as Potential Mattress Filling Materials.

Luffa sponge (LS) is a resourceful material with fibro-vascular reticulated structure and extremely high porosity, which make it a potential candidate for manufacturing light mattress. In this study, two types of LS columns, namely high-density (HD) and low-density (LD) columns, were investigated as materials for filling the mattress. The results showed that the compressive strength of HD LS columns was significantly greater than that of LD LS columns. However, the densification strains of the two types of LS column were both in the range of 0.6 to 0.7. Besides, HD LS columns separately pressed to the smooth plateau region and the initial densification region exhibited a partial recovery of instant height when they were unloaded, and then both of them showed no more than 4.2% of height recovery after being allowed to rest at a constant temperature and humidity for 24 h. In contrast, when LD LS columns were compressed to the smooth plateau region, the height recovery was less than 1.62% compared to when they were pressed to the initial densification region, and that was more than 15.62%. Similar to other plant fibers used as mattress fillers, the two types of LS columns also showed good water absorption capacity-both of them could absorb water from as much as 2.07 to 3.45 times their own weight. At the same time, the two types of LS columns also showed good water desorption. The water desorption ratio of HD and LD LS columns separately reached 76.86 and 91.44%, respectively, after being let rest at a constant temperature and humidity for 13 h.