Mechanical properties of 2D Zrn+1Cn(n= 1, 2) MXenes with and without functionalization.

Transition metal carbides and nitrides (MXenes) are considered the new generation of flexible electronic materials because of their superior mechanical strength and flexibility. Based on the density functional theory, the structures, electronic properties and mechanical properties of the 2D Zr-based MXenes with and without surface functional groups (O, F and OH) are investigated systematically to explore their elastic properties and tensile fracture mechanism. The results reveal the tensile strength and critical strain under biaxial tensile direction can reach 52 GPa, 12% for Zr2C and 55 GPa, 19% for Zr3C2, more outstanding than the mechanical behavior of the pristine Ti2C (47 GPa, 9.5%). The tensile behaviors of the functionalized Zrn+1CnT2(n= 1, 2, T = O, F, OH) strongly depend on the crystallographic orientation and the surface functional group. The phonon spectrum under the critical strain indicates the tensile fracture of the pristine Zr-based MXenes was determined by phonon instability, except along the armchair direction of Zr2C and zigzag direction of Zr3C2. During tensile strain, the collapse of Zrn+1CnF2and Zrn+1Cn(OH)2(n= 1, 2) are mainly caused by internal Zr-C bond rupture and transfer to the surface. While the O-functionalized Zrn+1CnO2(n= 1, 2) presented the opposite collapse trend. Additionally, according to the research results of critical strain, elastic modulus and electrical conductivity, F/OH-terminated Zr2C MXene is relatively more suitable for flexible sensors of wearable devices than Zr3C2T2.

Mycoplasma pneumoniae among Chinese Outpatient Children with Mild Respiratory Tract Infections during the Coronavirus Disease 2019 Pandemic.

Mycoplasma pneumoniae is a common pathogen causing respiratory disease in children. We sought to investigate the epidemiology of M. pneumoniae among outpatient children with mild respiratory tract infections (RTIs) during the coronavirus disease 2019 (COVID-19) pandemic. Eligible patients were prospectively enrolled from January 2020 to June 2021. Throat swabs were tested for M. pneumoniae RNA. M. pneumoniae IgM was tested by a colloidal gold assay. Macrolide resistance and the effect of the COVID-19 countermeasures on M. pneumoniae prevalence were assessed. Symptom scores, treatments, and outcomes were evaluated. Eight hundred sixty-two eligible children at 15 centers in China were enrolled. M. pneumoniae was detected in 78 (9.0%) patients. Seasonally, M. pneumoniae peaked in the first spring and dropped dramatically to extremely low levels over time until the next summer. Decreases in COVID-19 prevalence were significantly associated with decreases in M. pneumoniae prevalence (r = 0.76, P = 0.001). The macrolide resistance rate was 7.7%. The overall sensitivity and specificity of the colloidal gold assay used in determining M. pneumoniae infection were 32.1% and 77.9%, respectively. No more benefits for improving the severity of symptoms and outcomes were observed in M. pneumoniae-infected patients treated with a macrolide than in those not treated with a macrolide during follow-up. The prevalences of M. pneumoniae and macrolide resistance in outpatient children with mild RTIs were at low levels in the early stage of the COVID-19 pandemic but may have rebounded recently. The colloidal gold assay for M. pneumoniae IgM may be not appropriate for diagnosis of M. pneumoniae infection. Macrolides should be used with caution among outpatients with mild RTIs. IMPORTANCE This is the first and largest prospective, multicenter, active, population-based surveillance study of the epidemiology of Mycoplasma pneumoniae among outpatient children with mild respiratory tract infections (RTIs) during the COVID-19 pandemic. Nationwide measures like strict face mask wearing and restrictions on population movement implemented to prevent the spread of COVID-19 might also effectively prevent the spread of M. pneumoniae. The prevalence of M. pneumoniae and the proportion of drug-resistant M. pneumoniae isolates in outpatient children with mild RTIs were at low levels in the early stage of the COVID-19 pandemic but may have rebounded recently. The colloidal gold assay for M. pneumoniae IgM may be not appropriate for screening and diagnosis of M. pneumoniae infection. Macrolides should be used with caution among outpatients with mild RTIs.

A novel two-dimensional beryllium diphosphide (BeP2) with superconductivity: the first-principles exploration.

In this study, three stable two-dimensional beryllium diphosphide (2D-BeP2) structures with the wrinkle and planar monolayers, namely MoS2-like 6[combining macron]m-BeP2 phase (1H-BeP2), pentagonal 4[combining macron]2m-BeP2 (Penta-BeP2) and planar mm2-BeP2 (Planar-BeP2), have been successfully predicted through the first-principles calculation combined with a global structure search method. The structural stabilities, mechanical properties, electron properties and superconductivities are also systematically investigated. Results indicated that the 2D MoS2-like 1H-BeP2 showed higher stability than the Penta- and Planar-BeP2 structures. The 1H-BeP2 structure possessed an intrinsic metallic characteristics with the bands crossing the Fermi level. Notably, the Penta-BeP2 is a typical semiconductor, and the planar-BeP2 is semi-metal with Dirac corn. Based on the calculation results of the electron properties, phonon properties and electron-phonon coupling (EPC), the layer 1H-BeP2 sheet is a phonon-mediated superconductor with a critical temperature (Tc) of about 1.32 K.

Loss of interleukin-6 enhances the inflammatory response associated with hyperoxia-induced lung injury in neonatal mice.

In bronchopulmonary dysplasia (BPD), decreased angiogenesis and alveolarization is associated with pulmonary cell death and inflammation. It is commonly observed in premature infants who required mechanical ventilation and oxygen therapy. Since enhanced interleukin-6 (IL-6) expression has been reported in infants with BPD, it was hypothesized that a decrease in IL-6 may enhance lung inflammation and decrease hyperoxia-induced neonatal lung injury in mice. In the current study, newborn wild-type (WT) and IL-6 null mice were treated with 85% O2 (hyperoxia) or 21% O2 (normoxia) for 96 h. Although the increased volume and decreased quantity of alveoli was triggered by hyperoxia in WT and IL-6 null mice, transcription and translation of proinflammatory cytokines (monocyte chemoattractant protein-1, IL-10, IL-12 and tumor necrosis factor-α) and pulmonary cell death (caspase stimulation and terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling staining) were significantly enhanced in IL-6 null mice compared with WT mice. These results suggest that the crosstalk between inflammation and cell death may be involved in hyperoxia-induced lung injury in BPD. Future treatment approaches for bronchopulmonary dysplasia should be based on the suppression of cytokine expression.

Identification of differentially expressed genes associated with asthma in children based on the bioanalysis of the regulatory network.

Asthma, the most common chronic respiratory tract disease in children, is characterized by allergy, recurring airway obstruction and bronchospasm. The aim of the present study was to screen critical differentially expressed genes (DEGs) involved in asthma in children. Gene expression in different tissues was compared between asthmatic children and healthy control subjects in order to identify DEGs associated with asthma. Protein­protein interaction (PPI) networks were constructed for the DEGs and weighted gene co­expression network analysis methods were used to further determine the functional modules associated with DEGs in different tissue samples. In addition, the gene co­expression network was constructed. Gene Ontology function analysis and pathway analysis were conducted to identify critical DEGs. The results identified numerous DEGs from the different tissue samples, including 1,662 DEGs from nasal­epithelium tissue samples, 572 DEGs from peripheral blood (PB) samples and 146 DEGs from PB mononuclear cells samples. In the PPI network, F­box only protein 6 (FBXO6), histone deacetylase 1 (HDAC1) and amyloid ß precursor protein (APP) were hub genes and served an important role in the process of asthma. In addition, proliferating cell nuclear antigen (PCNA), integrin α­4 (ITGA4), catenin α­1 (CTNNA1), nuclear factor­κB1 (NF­κB1) and mechanistic target of rapamycin (MTOR) may be critical DEGs involved in the progression of asthma in children. These results suggested that FBXO6, HDAC1 and APP may interact with PCNA, ITGA4, CTNNA1, NF­κB1 and mTOR in the progression of asthma in children.

Zika virus: The transboundary pathogen from mosquito and updates.

Zika virus (ZIKV) is a mosquito-borne flavivirus that was relatively obscure until outbreaks started in 2013. ZIKV is associated with neurological manifestations such as Guillan-Barrè Syndrome in adult and microcephaly in the newborn population. Although the majority of disease mechanisms of ZIKV is unclear, some information was updated with new scientific evidence. Currently, there are no approved drugs or vaccine that can be used for therapy during ZIKV infection. Based on the transmission mechanism of ZIKV, vector control and safe sex seem to be the most effective available preventive measures against ZIKV spread. This study summarized the current ZIKV epidemiology, the status of the existing pathogenic mechanism of ZIKV, the development of potential compounds and vaccines against ZIKV, and the control efforts against ZIKV.

[Effect of regional synergistic treatment system on the treatment time and short-term prognosis of ST-segment elevation myocardial infarction].

OBJECTIVE: To explore the effect of regional synergistic treatment system on the treatment time and short-term prognosis of patients with ST-segment elevation myocardial infarction (STEMI). METHODS: A retrospective analysis of the clinical data of STEMI patients who admitted to emergency center of Suzhou Kowloon Hospital Affiliated to Shanghai Jiaotong University School of Medicine and underwent primary percutaneous coronary intervention (PPCI) from January 2013 to January 2017 were conducted. All patients were divided into two groups, group A was the patients who underwent the PPCI before the establishment of the acute chest pain area co-treatment system (from January 2013 to December 2014), and group B was the patients who received the treatment after the establishment of the area co-treatment system (from January 2015 to January 2017). The length of time from onset of symptoms to the balloon dilatation (S2B), the length of time from the first medical contact to the balloon dilatation (FMC2B), the length of time from entering the gate of hospital to the balloon dilatation (D2B), and the incidence of 90-day end point events (including heart failure, all-cause death, and other related adverse events) were collected. The relations of the establishment of the acute chest pain area co-treatment system and the incidence of 90-day end point events were analyzed by multivariable Logistic regression analysis. RESULTS: Among the 221 enrolled patients with STEMI, 83 patients were in group A and 138 patients were in group B respectively. Compared with group A, S2B time [minutes: 180 (140, 210) vs. 201 (154, 225)], FMC2B time [minutes: 89 (78, 100) vs. 94 (83, 107)] and D2B time [minutes: 66 (62, 70) vs. 85 (72, 99)] were significantly shortened in group B (all P < 0.05), the incidence of 90-day end point events were significantly decreased (heart failure: 20.3% vs. 32.5%, all-cause death: 1.4% vs. 7.2%, other related adverse events: 23.2% vs. 36.1%, all P < 0.05). It was shown by multivariable Logistic regression analysis that the establishment of the acute chest pain area co-treatment system could lower the incidence of 90-day end point events [heart failure: odds ratio (OR) = 1.904, 95% confidence interval (95%CI) = 0.968-1.004, P = 0.048; all-cause death: OR = 11.724, 95%CI = 0.955-1.048, P = 0.013; other related adverse events: OR = 1.925, 95%CI = 1.049-3.530, P = 0.034]. CONCLUSIONS: The construction of regional synergistic treatment system can shorten the emergency treatment time of STEMI patients and reduce the incidence of 90-day end point events including heart failure and death.