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Good nursing leadership management positively correlates with patient care quality and an organization's performance. Plans to nurture top-notch talents and strengthen management functions are essential to retain key talents and achieve sustainability. The leadership training for nursing staff should begin early to cope with complex clinical situations. To compare the impact of leadership training on high-performing young nurses' (young nursing elite) management functions and team behavior. A public teaching hospital in Taipei, Taiwan. This research implemented a longitudinal quasi-experimental study with a fixed time series design; the target subjects were youth nursing elites who received training, along with their direct managers and peers, for a total of 102 participants. The training course intervention included the classroom teaching of leadership management functions, arranging internships in the hospital's internal administrative units and professional nursing institutions, and the direct managers sharing their experiences during teaching. We measured the outcome indicators before the course intervention, at the end of the course intervention, and three months after using the management function and team behavior scales. The mean score of the direct managers' assessments regarding the youth nursing elite's pre-test team behavior was 4.18. This improved by 0.68 points (p <.001) after the program intervention and improved by 0.65 points (p <.001) three months after the program compared to the pre-test. There was no statistically significant difference between the two groups as analyzed using GEE. The mean score of the pre-test self-assessment management function of the young nursing elite was 3.27. This improved by 1.06 points (p <.001) after the program intervention and by 1.14 points (p <.001) three months after the program compared to the pre-test. There was no statistically significant difference between the three groups using GEE analysis. Leadership training enhances young nursing professionals' leadership function and team behavior. • Diversified leadership function training can effectively improve the management function of youth nursing elites. • Planned elites selection should start from the young generation to cultivate nursing leaders. • Nursing leadership training should include nursing professional community and policy participation. [ABSTRACT FROM AUTHOR]

Atmospheric exposure is an important pathway of accumulation of lead (Pb) in Oryza sativa L. grains. In this study, source contributions of soil, early atmospheric exposure, and late atmospheric exposure, along with their bioaccumulation ratios were examined both in the pot and field experiments using stable Pb isotope fingerprinting technology combined with a three-compartment accumulation model. Furthermore, genotype differences in airborne Pb accumulation among four field-grown rice cultivars were investigated using the partial least squares path model (PLS-PM) linking rice Pb accumulation to agronomic traits. The findings revealed that during the late growth period, the air-foliar-grain transfer of Pb was crucial for rice Pb accumulation. Approximately 69–82% of the Pb found in polished rice was contributed by atmospheric source, with more than 80% accumulating during the late growth stage. The air accumulation ratios of rice grains were genotype-specific and estimated to be 0.364–1.062 m3/g during the late growth. Notably, grain size exhibited the highest standardized total effects on the airborne Pb concentrations in the polished rice, followed by leaf Pb and the upward translocation efficiency of Pb. The present study indicates that mitigating the health risks associated with Pb in rice can be achieved by controlling atmospheric Pb levels during the late growth stage and choosing Japonica inbred varieties characterized by large grain size. [Display omitted] • Air-foliar-grain transfer of Pb in the late growth period was crucial for rice Pb. • Air Pb accumulation ratios of rice grains were genotype-specific. • Both stomatal and panicle characteristics influenced foliar Pb accumulation. • Grain size exhibited the highest total effects on the airborne rice Pb concentrations. [ABSTRACT FROM AUTHOR]

Background: As of June 8, 2020, the global reported number of COVID-19 cases had reached more than 7 million with over 400 000 deaths. The household transmissibility of the causative pathogen, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains unclear. We aimed to estimate the secondary attack rate of SARS-CoV-2 among household and non-household close contacts in Guangzhou, China, using a statistical transmission model.Methods: In this retrospective cohort study, we used a comprehensive contact tracing dataset from the Guangzhou Center for Disease Control and Prevention to estimate the secondary attack rate of COVID-19 (defined as the probability that an infected individual will transmit the disease to a susceptible individual) among household and non-household contacts, using a statistical transmission model. We considered two alternative definitions of household contacts in the analysis: individuals who were either family members or close relatives, such as parents and parents-in-law, regardless of residential address, and individuals living at the same address regardless of relationship. We assessed the demographic determinants of transmissibility and the infectivity of COVID-19 cases during their incubation period.Findings: Between Jan 7, 2020, and Feb 18, 2020, we traced 195 unrelated close contact groups (215 primary cases, 134 secondary or tertiary cases, and 1964 uninfected close contacts). By identifying households from these groups, assuming a mean incubation period of 5 days, a maximum infectious period of 13 days, and no case isolation, the estimated secondary attack rate among household contacts was 12·4% (95% CI 9·8-15·4) when household contacts were defined on the basis of close relatives and 17·1% (13·3-21·8) when household contacts were defined on the basis of residential address. Compared with the oldest age group (≥60 years), the risk of household infection was lower in the youngest age group (<20 years; odds ratio [OR] 0·23 [95% CI 0·11-0·46]) and among adults aged 20-59 years (OR 0·64 [95% CI 0·43-0·97]). Our results suggest greater infectivity during the incubation period than during the symptomatic period, although differences were not statistically significant (OR 0·61 [95% CI 0·27-1·38]). The estimated local reproductive number (R) based on observed contact frequencies of primary cases was 0·5 (95% CI 0·41-0·62) in Guangzhou. The projected local R, had there been no isolation of cases or quarantine of their contacts, was 0·6 (95% CI 0·49-0·74) when household was defined on the basis of close relatives.Interpretation: SARS-CoV-2 is more transmissible in households than SARS-CoV and Middle East respiratory syndrome coronavirus. Older individuals (aged ≥60 years) are the most susceptible to household transmission of SARS-CoV-2. In addition to case finding and isolation, timely tracing and quarantine of close contacts should be implemented to prevent onward transmission during the viral incubation period.Funding: US National Institutes of Health, Science and Technology Plan Project of Guangzhou, Project for Key Medicine Discipline Construction of Guangzhou Municipality, Key Research and Development Program of China. [ABSTRACT FROM AUTHOR]

Objective: Chinese pediatricians are working on the front line to fight COVID-19. They have published a great amount of first-hand clinical data. Collecting their data and forming a large sample for analysis is more conducive to the recognition, prevention and treatment of coronavirus disease 2019 in children. The epidemic prevention and control experience of Chinese pediatricians should be shared with the world.Methods: By searching Chinese and English literature, the data of 406 children with COVID-19 in China were analyzed.Results: It was found that the clustered incidence of children's families is a dynamic transmission feature; the incidence is low; asymptomatic infections and mild cases account for 44.8%, with only 7 cases of critical illness; laboratory examination of lymphocyte counts is not reduced, as it is for adults; chest CT findings are less severe than those for adults. These presentations are the clinical features of COVID-19 in children. Only 55 of the 406 cases were tested by anal swab for virus nucleic acid, 45 of which were positive, accounting for 81.8% of stool samples.Conclusion: There are more children than adults with asymptomatic infections, milder conditions, faster recovery, and a better prognosis. Some concealed morbidity characteristics also bring difficulties to the early identification, prevention and control of COVID-19. COVID-19 screening is needed in the pediatric fever clinic, and respiratory and digestive tract nucleic acid tests should be performed. Efforts should be made to prevent children from becoming a hidden source of transmission in kindergartens, schools or families. Furthermore, China's experience in treating COVID-19 in children has led to faster recovery of sick children. [ABSTRACT FROM AUTHOR]

The U.S. has emerged as the microgrid development leader with around 40% of worldwide capacity. Over the last decade, demonstrations have been executed by a mix of civilian federal, military, private, and local government entities. While their motivations are mixed, resilience became the focus following Superstorm Sandy in 2012, especially in the highly active northeast states. This paper describes U.S. microgrid demonstrations. Then it shows China’s effort to develop microgrids and compares the difference between U.S. and Chinese projects. Finally, based on U.S. experience, recommendations are provided for Chinese microgrids. [ABSTRACT FROM AUTHOR]

Two oxidovanadium(IV) complexes carrying Schiff base ligands obtained from the condensation of 4,5-dichlorobenzene-1,2-diamine and salicylaldehyde derivatives were synthesised and characterised, including their X-ray crystallographic structures. They were evaluated as dipeptidyl peptidase IV (DPP-IV) inhibitors for the treatment of type 2 diabetes. These compounds were moderate inhibitors of DPP-IV, with IC 50 values of ca. 40 μM. In vivo tests showed that complexes 1 and 2 could lower significantly the level of glucose in the blood of alloxan-diabetic mice at doses of 22.5 mg V·kg − 1 and 29.6 mg V·kg − 1 , respectively. Moreover, molecular modeling studies suggested that the oxidovanadium complexes 1 and 2 could fit well into the active-site cleft of the kinase domain of DPP-IV. To the best of our knowledge, this is the first report of vanadium complexes capable of inhibiting DPP-IV. [ABSTRACT FROM AUTHOR]

Peritoneal adhesion is one of the common complications after abdominal surgery. Injectable thermosensitive hydrogel could serve as an ideal barrier to prevent this postoperative tissue adhesion. In this study, poly( N -isopropylacrylamide) (PNIPAm) was grafted to chitosan (CS) and the polymer was further conjugated with hyaluronic acid (HA) to form thermosensitive HA-CS-PNIPAm hydrogel. Aqueous solutions of PNIPAm and HA-CS-PNIPAm at 10%(w/v) are both free-flowing and injectable at room temperature and exhibit sol-gel phase transition around 31 °C; however, HA-CS-PNIPAm shows less volume shrinkage after gelation and higher complex modulus than PNIPAm. Cell culture studies indicate both injectable hydrogel show barrier effects to reduce fibroblasts penetration while induce little cytotoxicity in vitro. From a sidewall defect-bowel abrasion model in rats, significant reduction of postoperative peritoneal adhesion was found for peritoneal defects treated with HA-CS-PNIPAm compared with those treated with PNIPAm and untreated controls from gross and histological evaluation. Furthermore, HA-CS-PNIPAm did not interfere with normal peritoneal tissue healing and did not elicit acute toxicity from blood analysis and tissue biopsy examination. By taking advantage of the easy handling and placement properties of HA-CS-PNIPAm during application, this copolymer hydrogel would be a potentially ideal injectable anti-adhesion barrier after abdominal surgeries. [ABSTRACT FROM AUTHOR]

Background Depression and anxiety among general hospital patients are common and under-recognized in China. This study aimed toward developing a short questionnaire for screening depression and anxiety in non-psychiatric clinical settings, and to test its reliability and validity. Methods The item pool which included 35 questions about emotional distress was drafted through a comprehensive literature review. An expert panel review and the first clinical test with 288 general hospital patients were conducted for the primary item selection. The second clinical test was performed to select the final item in 637 non-psychiatric patients. The reliability and validity of the final questionnaire were tested in 763 non-psychiatric patients, in which 211 subjects were interviewed by psychiatrists using Mini International Neuropsychiatric Interview (MINI). Multiple data analysis methods including principal components analysis (PCA), item response theory (IRT), and receiver operating characteristic (ROC) curve were used to select items and validate the final questionnaire. Results The series selection of items resulted in a 9-item questionnaire, namely Huaxi Emotional-distress Index (HEI). The Cronbach's α coefficient of HEI was 0.90. The PCA results showed a unidimensional construct. The area under the ROC curve (AUC) was 0.88 when compared with MINI interview. Using the optimal cut-off score of HEI (11/12), the sensitivity and specificity were 0.880 and 0.766, respectively. Conclusions The HEI is considered as a reliable and valid instrument for screening depression and anxiety, which may have substantial clinical value to detect patients' emotional disturbances especially in the busy non-psychiatric clinical settings in China. [ABSTRACT FROM AUTHOR]

Zinc has been widely deployed as an anode of zinc ion batteries (ZIBs) due to high safety, high theoretical capacity, and low potential. However, dendrite growth and side reactions still severely hampered scale-up implementation in ZIBs. Here, organic hydrophobic polyvinylidene fluoride and inorganic Santa Barbara Amorphous-15 (PVDF-SBA15) hybrids were designed as a surface modification layer to stabilize Zn anode, leading to an optimized Zn/electrolyte interface with large-scale feasibility. The PVDF-SBA15 surface modification realizes synergistic protection on zinc anode since the hydrophobic PVDF could avoid the side reactions through prevention of direct contact between the zinc and the electrolyte, while the evenly distributed porous structure of SBA15 can induce uniform zinc plating/stripping and inhibit dendrite growth by uniform zinc ions flux. The hydrophobic PVDF-SBA15 surface-modified Zn anode (PVDF-SBA15 @Zn) exhibits dendrite-free Zn plating/stripping with low overpotential after 1650 h at a current density of 3 mA cm−2 in symmetrical batteries. The PVDF-SBA15 @Zn||V 2 O 5 full batteries enable the stable cycling of 82.14 % capacity retention after 1000 cycles compared with 23.55 % of Zn||V 2 O 5. The effectively inhibited dendrite growth and side reactions on Zn anode through hydrophobic organic-inorganic surface modification layer provide solid foundation for the realization of ultra-stable zinc ion batteries. [Display omitted] • Hydrophobic PVDF-SBA15 coating was constructed to synergistically avoid dendrite growth and side reactions on the Zn anode. • The PVDF-SBA15@ZnZn anode exhibits dendrite-free Zn plating/stripping with a low overpotential of 39 mV after 3800 h. • The PVDF-SBA15@Zn||V 2 O 5 batteries enable the stable cycling of 82.14 % capacity retention after 1000 cycles compared with 23.55 % of Zn||V 2 O 5. [ABSTRACT FROM AUTHOR]

(100–x wt%) La 0.85 Sr 0.15 Ga 0.8 Mg 0.2 O 2.825 (LSGM1520) + (x wt%) Ce 0.85 Sm 0.15 O 1.925 (SDC15)( x = 0, 2, 5, 7, 10, and 100) composite electrolytes were synthesized by a solid-state reaction. The microstructures and electrical properties of the electrolytes were analyzed by X-ray diffractometry, Raman spectroscopy, scanning electron microscopy, thermomechanical analysis, and impedance spectroscopy. The electrolytes, LSGM1520 and 95 wt% LSGM1520–5 wt% SDC15, based on a La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3− δ (LSCF6428) cathode and Ce 0.8 Sm 0.2 O 1.9 –Ni (SDC20-Ni) cathode were used to form two SOFCs. The thermal expansion coefficients of the composites ranged from 10.5 × 10 −6 /°C to 12 × 10 −6 /°C at 200–600 °C and 12 × 10 −6 /°C to 15 × 10 −6 /°C at 600–800 °C. The performances and current density of LSCF6428/LSGM1520/SDC20-Ni and LSCF6428/95L05S/SDC20-Ni are 264 mW/cm 2 and 1.00 A/cm 2 at 774 °C, and 182 mW/cm 2 and 0.97 A/cm 2 at 789 °C, respectively, and their open circuit voltages (OCV) are ∼1.0–1.1 V. [ABSTRACT FROM AUTHOR]

A new alkaloid featured with a dibenz[ c , e ]azepin-5-one scaffold, namely emililactam A (3), together with a known pyrrolidine alkaloid (emilisonchine, 1) and a known flavonoid alkaloid [8-(2″-pyrrolidinone-5″-yl)-quercetin, 2 ] were isolated from the aerial parts of Emilia sonchifolia. Compounds 1 and 2 were isolated as racemic forms which were further separated, for the first time, to their corresponding enantiomers [(+)- 1 /(−)- 1 and (+)- 2 /(−)- 2 ], respectively, by using chiral-phase HPLC. The structure of new compound 3 was elucidated by extensive spectroscopic analysis. In addition, the absolute configurations of optically pure (+)- 1 /(−)- 1 and (+)- 2 /(−)- 2 were determined by the time-dependent density functional theory electronic circular dichroism (TDDFT-ECD) calculations. In an in vitro bioassay, compounds (+)- 1 , (−)- 1 , (±)- 1 , and 3 exhibited moderate neuroprotective effects against corticosterone-induced injuries of PC12 cells. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: The directional and hemispherical transmittance through four microscale slit arrays on a semitransparent substrate were investigated at normal incidence. Materials and vertical dimensions of all arrays were the same, but lateral dimensions varied among the three simple slit arrays. The complex slit array had three identical slits and three lamellae of dissimilar widths in a profile period. The incidence covered a broad-band mid-infrared region (2.5–25μm) in which two linear polarizations were considered. Impacts of the structure profile, incidence polarization and wavelength, and optical constants of involved materials on spectra were studied numerically with programs based on the algorithm termed rigorous coupled-wave analysis (RCWA). Near-field patterns of electromagnetic fields that correlated with unique transmittance were also plotted to identify responsible physical mechanisms. In addition, the directional transmittance spectra of fabricated samples were measured with FT-IR spectrometry. Reasonable agreement between numerical and experimental results was obtained. Unique features in spectra were consistently found, regardless of the finite substrate thickness. [Copyright &y& Elsevier]

Abstract: The effect of the chloro-substitution of dinuclear vanadium (V) complexes on lowering diabetic hyperglycemia was evaluated. The in vivo tests for hypoglycemic activity show that complex 2 at the dose of 10.0 and 20.0 mg V kg−1, could significantly decrease the blood glucose level. Importantly, our results the chloro substituent increased the insulin-enhancing properties of the complex 2. The two vanadium compounds had permeability above 10−5 cm/s. It suggested that two complexes permeate via a passive diffusion mechanism. It was also suggested that two complexes has better good lipophilic properties. The cytotoxicity of two complexes on Caco-2 cells suggested the chlorine atom at C4 of complex 2 increased cytotoxicity for vanadium complexes. [ABSTRACT FROM AUTHOR]

Abstract: A new insulin-enhancing oxovanadium complex 5-chloro-salicylaldhyde ethylenediamine oxovanadium (V) ([V2O2(μ-O)2L2]) has been synthesized. The complex was characterized by a variety of physical methods, including X-ray crystallography. The X-ray diffraction analysis show a dinuclear complex of two six-coordinate vanadium centers doubly bridged by the oxygen atoms of the Schiff base ligand with a V2O2 diamond core. The complex was administered intragastrically to STZ-diabetic rats for 2weeks. The biological activity results show that the complex at the dose of 10.0 and 20.0mgVkg−1, could significantly decrease the blood glucose level and ameliorate impaired glucose tolerance in STZ-diabetic rats. That results suggested that the complex exerts an antidiabetic effect in STZ-diabetic rats. Furthermore, the complex ([V2O2(μ-O)2L2]) had permeability above 10−5 cm/s. The experimental results suggested that the vanadium complex permeates via a passive diffusion mechanism. It was also suggested the complex with salen-type ligands has good lipophilic properties and better oral administration. The cytotoxicity of the complex ([V2O2(μ-O)2L2]) on Caco-2 cells was measured by a decrease of cell viability using the MTT assay suggesting that the chlorine atom at C4 of complex [V2O2(μ-O)2L2] increased cytotoxicity for vanadium complexes. [Copyright &y& Elsevier]

Abstract: A new insulin-enhancing agent: [N,N′-bis(4-hydroxysalicylidene)-o-phenylene-diamine] oxovanadium(IV) (BPOV) was synthesized and characterized by X-ray crystallography. BPOV was administered intragastrically to STZ-diabetic rats for 4 weeks. The results showed that BPOV could significantly decrease the blood glucose level and ameliorated impaired glucose tolerance in STZ-diabetic rats. BPOV has been further tested on insulin, glycogen and serum lipid studies. The results suggested BPOV has glucose-lowering activity in diabetic rats, as well as improved the disorder of lipid metabolism in diabetes. BPOV had permeability above 10−5 cms−1. It was suggested good lipophilic properties. The cytotoxicity of BPOV on Caco-2 cells was measured by MTT assay which suggested BPOV have higher effect on impairment of cellular associated with lower level capacity of cellular accumulation. [Copyright &y& Elsevier]

Triboelectric nanogenerator (TENG) is a new energy technology, which can effectively convert ambient various mechanical energy into electricity by coupling effect of triboelectrification and electrostatic induction, yielding self-powered microelectronic devices. However, the surface charge density of triboelectric materials and the performance degradation and failure of TENG caused by wear are the key bottlenecks for its practical application. Here, we propose a high-performance and long-life TENG for harvesting wind energy that uses polyvinyl chloride/molybdenum disulfide (PVC/MoS 2) composite membranes and polyamide (PA) membranes as matching triboelectric materials, and aluminum (Al) sheets with micro-nano structures as electrodes. Adding a small amount of MoS 2 with excellent lubricating properties can not only effectively increase the surface charge density of composite films but also improve its wear resistance, which enhances the output performance and extends the life time of the TENG. The optimized TENG can generate an output voltage, current and maximum power up to 398 V, 40 μA and 1.23 mW, respectively, which can power tens of commercial light-emitting diodes (LEDs) and a water thermometer. Moreover, the friction coefficient of PVC after the doping of 2.5 wt% MoS 2 is 0.29, which is 19.4% lower than that of pure PVC film, providing a new way to improve the surface charge density and the durability of triboelectric materials. [Display omitted] • Solid lubrication is used for the first time to enhance the outperformance and extend the service lifetime of TENG. • The optimized TENG can generate an output voltage, current and maximum power up to 398 V, 40 μA and 1.23 mW. • The friction coefficient of pure PVC membrane is approximately 0.36 while the friction coefficient of the PVC/MoS 2 composite membrane is 0.29. [ABSTRACT FROM AUTHOR]

Lupus nephritis is a frequent and serious complication of systemic lupus erythematosus (SLE), the treatment of which often requires the use of immunosuppressives that can have severe side effects. Here we determined the low-molecular weight proteome of serial lupus urine samples to uncover novel and predictive biomarkers of SLE renal flare. Urine from 25 flare cycles of 19 patients with WHO Class III, IV, and V SLE nephritis were obtained at baseline, pre-flare, flare and post-flare. Each sample was first fractionated to remove proteins larger than 30 kDa, then applied onto weak cation exchanger protein chips for analysis by SELDI-TOF mass spectrometry. We found 176 protein ions of which 27 were differentially expressed between specific flare intervals. On-chip peptide sequencing by integrated tandem mass spectrometry positively identified the 20 and 25 amino-acid isoforms of hepcidin, as well as fragments of α1-antitrypsin and albumin among the selected differentially expressed protein ions. Hepcidin 20 increased 4 months before renal flare and returned to baseline at renal flare, whereas hepcidin 25 decreased at renal flare and returned to baseline 4 months after the flare. These studies provide a beginning proteomic analysis aimed at predicting impending renal relapse, relapse severity, and the potential for recovery after SLE nephritis flare.Kidney International (2008) 74, 799–807; doi:10.1038/ki.2008.316; published online 2 July 2008 [ABSTRACT FROM AUTHOR]

Abstract: The reaction of cyclohexyl isocyanide with various aldehydes and 1,3-dicarbonyl compounds catalyzed by piperidine is described. The protocol offers facile and efficient synthesis of 5-hydroxy-2H-pyrrol-2-one derivatives from readily available starting materials in high yields. [Copyright &y& Elsevier]

Abstract: The reaction of acids, alcohols, acylamides, 1,2-diols, 1,2-diamines or amino alcohols with activated alkynes catalyzed by 1,4-diazabicyclo[2.2.2]octane (DABCO) was systematically investigated. A series of unsaturated alkenoic acid esters or heterocycles were formed in the reaction of monobasic or dibasic nucleophiles in excellent yields, respectively. [Copyright &y& Elsevier]

Abstract: Effective components, ligustilide and butylidenephthalide, from Ligusticum Chuanxiong (Ligusticum wallichii Franchat, Umbelliferae) were screened and identified by using a cell membrane chromatography (CMC) and a gas chromatography/mass spectrometry (GC/MS). The components showed the effects of inhibiting vasoconstriction in vitro on rat abdominal aorta segments. The screening procedure was performed in a rat artery CMC column (50 mm×2.0 mm I.D.) with a sodium phosphate buffer (pH 7.4) as mobile phase at 37 °C. The identification was accomplished by a DB-5MS 30 m capillary column (0.25 mm I.D., 0.25 μm film thickness) with helium as carrier gas operating under program control temperature and electron impact ionization mass spectrometer in a scan mode. Results demonstrated that ligustilide and butylidenephthalide can act on rat artery cell membrane similar to verapamil in CMC system. They significantly inhibited the vasoconstrictions induced by norepinephrine bitartrate (NE) and calcium chloride (CaCl2). The relaxing effect of ligustilide on the NE- and CaCl2-induced constrictions is more potent than that of butylidenephthalide. Ligustilide and butylidenephthalide seem to be the two main effective components of Ligusticum Chuanxiong as a traditional Chinese medicine for treating blood vessel diseases. [Copyright &y& Elsevier]

Failures caused by environmental stress cracking (ESC) in polymers, especially amorphous ones, pose substantial concerns for their safety issues and long-term applications. Herein, we proposed a strategy through volume pulsation injection molding (VPIM) to delay the cracking by extending the solvent diffusion path and modulating the crystallization behavior of semi-crystalline polymers. High-impact polystyrene (HIPS) was employed as a model material with high-density polyethylene (HDPE) as the ESC resistor. The as-prepared blend after the VPIM treatment can suffer 48 h of loaded oil immersion, which can be hardly achieved for reference samples prepared via the conventional injection molding (CIM) method and pure HIPS. Through in-depth investigations of the oil-stress treatment-induced ESC behaviors, we demonstrated the improvement in the anti-ESC performance can be attributed to the in-situ fiberization of HDPE during VPIM. This work will open new possibilities for improving the anti-ESC performance of polymers in practical applications. [Display omitted] • The exact mechanism of polymer cracking due to the coupling of reactive solvent materials with stress has been researched: The local plasticization caused by solvents is dominated at short processing time, while the molecular chain disentanglement will play a dominant role with the processing time increasing. • After VPIM, the as-prepared composite can suffer 48 h of loaded oil immersion and the tensile strength retention was up to 85.5 %, which can be hardly achieved for reference samples prepared via conventional injection molding (CIM) method and pure HIPS. • The formation of in-situ HDPE microfibers in the HIPS matrix plays a key role in the improvement of mechanical properties and ESC performance which can be effectively tuned by VPIM. On the one hand, the HDPE microfibers extend the solvent diffusion path and reduce the plasticizing and oxidation effect on the HIPS matrix. On the other hand, the increase in lamellar crystal areas creates a stronger barrier that impedes solvent penetration. [ABSTRACT FROM AUTHOR]

Background: Wuhan was the first epicentre of COVID-19 in the world, accounting for 80% of cases in China during the first wave. We aimed to assess household transmissibility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and risk factors associated with infectivity and susceptibility to infection in Wuhan.Methods: This retrospective cohort study included the households of all laboratory-confirmed or clinically confirmed COVID-19 cases and laboratory-confirmed asymptomatic SARS-CoV-2 infections identified by the Wuhan Center for Disease Control and Prevention between Dec 2, 2019, and April 18, 2020. We defined households as groups of family members and close relatives who did not necessarily live at the same address and considered households that shared common contacts as epidemiologically linked. We used a statistical transmission model to estimate household secondary attack rates and to quantify risk factors associated with infectivity and susceptibility to infection, accounting for individual-level exposure history. We assessed how intervention policies affected the household reproductive number, defined as the mean number of household contacts a case can infect.Findings: 27 101 households with 29 578 primary cases and 57 581 household contacts were identified. The secondary attack rate estimated with the transmission model was 15·6% (95% CI 15·2-16·0), assuming a mean incubation period of 5 days and a maximum infectious period of 22 days. Individuals aged 60 years or older were at a higher risk of infection with SARS-CoV-2 than all other age groups. Infants aged 0-1 years were significantly more likely to be infected than children aged 2-5 years (odds ratio [OR] 2·20, 95% CI 1·40-3·44) and children aged 6-12 years (1·53, 1·01-2·34). Given the same exposure time, children and adolescents younger than 20 years of age were more likely to infect others than were adults aged 60 years or older (1·58, 1·28-1·95). Asymptomatic individuals were much less likely to infect others than were symptomatic cases (0·21, 0·14-0·31). Symptomatic cases were more likely to infect others before symptom onset than after (1·42, 1·30-1·55). After mass isolation of cases, quarantine of household contacts, and restriction of movement policies were implemented, household reproductive numbers declined by 52% among primary cases (from 0·25 [95% CI 0·24-0·26] to 0·12 [0·10-0·13]) and by 63% among secondary cases (from 0·17 [0·16-0·18] to 0·063 [0·057-0·070]).Interpretation: Within households, children and adolescents were less susceptible to SARS-CoV-2 infection but were more infectious than older individuals. Presymptomatic cases were more infectious and individuals with asymptomatic infection less infectious than symptomatic cases. These findings have implications for devising interventions for blocking household transmission of SARS-CoV-2, such as timely vaccination of eligible children once resources become available.Funding: National Natural Science Foundation of China, Fundamental Research Funds for the Central Universities, US National Institutes of Health, and US National Science Foundation. [ABSTRACT FROM AUTHOR]

For the investigation of the initial post-buckling of a column built in at one end, clamped in rotation with a flexible support at the other, the stability of the bifurcation point is studied using the Fourier series. The second-order variation of the potential energy is proved to be semi-positive-definite at the bifurcation point. When the disturbance matches the buckling mode, the fourth-order variation is positive for some flexible support stiffness, and negative for other flexible support stiffness. Based on the Koiter's initial post-buckling theory, the condition on the flexible support stiffness conducive to the unstable branch path is derived. The unstable branch paths indicate that the buckling load of the column will be sensitive to the imperfections [ABSTRACT FROM AUTHOR]