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Let $\sigma \in (0,\,2)$ , $\chi ^{(\sigma)}(y):={\mathbf 1}_{\sigma \in (1,2)}+{\mathbf 1}_{\sigma =1} {\mathbf 1}_{y\in B(\mathbf {0},\,1)}$ , where $\mathbf {0}$ denotes the origin of $\mathbb {R}^n$ , and $a$ be a non-negative and bounded measurable function on $\mathbb {R}^n$. In this paper, we obtain the boundedness of the non-local elliptic operator \[ Lu(x):=\int_{\mathbb{R}^n}\left[u(x+y)-u(x)-\chi^{(\sigma)}(y)y\cdot\nabla u(x)\right]a(y)\,\frac{{\rm d}y}{|y|^{n+\sigma}} \] from the Sobolev space based on $\mathrm {BMO}(\mathbb {R}^n)\cap (\bigcup _{p\in (1,\infty)}L^p(\mathbb {R}^n))$ to the space $\mathrm {BMO}(\mathbb {R}^n)$ , and from the Sobolev space based on the Hardy space $H^1(\mathbb {R}^n)$ to $H^1(\mathbb {R}^n)$. Moreover, for any $\lambda \in (0,\,\infty)$ , we also obtain the unique solvability of the non-local elliptic equation $Lu-\lambda u=f$ in $\mathbb {R}^n$ , with $f\in \mathrm {BMO}(\mathbb {R}^n)\cap (\bigcup _{p\in (1,\infty)}L^p(\mathbb {R}^n))$ or $H^1(\mathbb {R}^n)$ , in the Sobolev space based on $\mathrm {BMO}(\mathbb {R}^n)$ or $H^1(\mathbb {R}^n)$. The boundedness and unique solvability results given in this paper are further devolvement for the corresponding results in the scale of the Lebesgue space $L^p(\mathbb {R}^n)$ with $p\in (1,\,\infty)$ , established by H. Dong and D. Kim [J. Funct. Anal. 262 (2012), 1166–1199], in the endpoint cases of $p=1$ and $p=\infty$. [ABSTRACT FROM AUTHOR]

Recently, polymer mechanochemistry has attracted much scientific interest due to its potential to develop degradable polymers. When the two ends of a polymer chain experience a linear pulling stress, molecular strain builds up, at sufficiently strong force, a bond scission of the weakest covalent bond results. In contrast, bond‐breaking events triggered by conformational stress are much less explored. Here, we discovered that a Zn salen complex would undergo conformational switching upon allosteric complexation with alkanediammonium guests. By controlling the guest chain length, the torsional strain experienced by Zn complex can be modulated to induce bond cleavage with chemical stimulus, and reactivity trend is predicted by conformational analysis derived by DFT calculation. Such strain‐release reactivity by a Zn(salen) complex initiated by guest binding is reminiscent of conformation‐induced reactivity of enzymes to enable chemical events that are otherwise inhibited. [ABSTRACT FROM AUTHOR]

Chiral vicinal diamines, a unique class of optically-active building blocks, play a crucial role in material design, pharmaceutical, and catalysis. Traditionally, their syntheses are all solvent-based approaches, which make organic solvent an indispensable part of their production. As part of our program aiming to develop chemical processes with reduced carbon footprints, we recently reported a highly practical and environmentally-friendly synthetic route to chiral vicinal diamines by solvent-free mechanochemical diaza-Cope rearrangement. We herein showed that a new protocol by co-milling with common laboratory solid additives, such as silica gel, can significantly enhance the efficiency of the reaction, compared to reactions in the absence of additives. One possible explanation is the Lewis acidic nature of additives that accelerates a key Schiff base formation step. Reaction monitoring experiments tracing all the reaction species, including reactants, intermediates, and product, suggested that the reaction profile is distinctly different from ball-milling reactions without additives. Collectively, this work demonstrated that additive effect is a powerful tool to manipulate a reaction pathway in mechanochemical diazo-Cope rearrangement pathway, and this is expected to find broad interest in organic synthesis using mechanical force as an energy input. [ABSTRACT FROM AUTHOR]

Metformin has been involved in modulating inflammatory state and inhibiting cell proliferation and angiogenesis. This study aimed to determine whether metformin alleviates airway inflammation and remodeling of experimental allergic asthma and elucidate the underlying mechanism. We sensitized and challenged mice with ovalbumin (OVA) to induce allergic asthma. During the challenge period, metformin was administered by intraperitoneal injection. By histopathological and immunohistochemical analyses, metformin-treated mice showed a significant alleviation in airway inflammation, and in the parameters of airway remodeling including goblet cell hyperplasia, collagen deposition and airway smooth muscle hypertrophy compared to those in the OVA-challenged mice. We also observed elevated levels of multiple cytokines (IL-4, IL-5, IL-13, TNF-α, TGF- β 1 and MMP-9) in the bronchoalveolar lavage fluid, OVA-specific IgE in the serum and angiogenesis-related factors (VEGF, SDF-1 and CXCR4) in the plasma from asthmatic mice, while metformin reduced all these parameters. Additionally, the activity of 5′-adenosine monophosphate-activated protein kinase a (AMPK α) in the lungs from OVA-challenged mice was remarkably lower than control ones, while after metformin treatment, the ratio of p -AMPK α to AMPK α was upregulated and new blood vessels in the sub-epithelial area as evidenced by CD31 staining were effectively suppressed. These results indicate that metformin ameliorates airway inflammation and remodeling in an OVA-induced chronic asthmatic model and its protective role could be associated with the restoration of AMPK α activity and decreased asthma-related angiogenesis. [ABSTRACT FROM AUTHOR]

Let and be a bounded NTA domain. In this article, the authors study (weighted) global regularity estimates for Neumann boundary value problems of second-order elliptic equations of divergence form with coefficients consisting of both an elliptic symmetric part and a BMO anti-symmetric part in. Precisely, for any given , via a weak reverse Hölder inequality with the exponent , the authors give a sufficient condition for the global estimate and the global weighted estimate, with and some Muckenhoupt weights, of solutions to Neumann boundary value problems in. As applications, the authors further obtain global regularity estimates for solutions to Neumann boundary value problems of second-order elliptic equations of divergence form with coefficients consisting of both a small symmetric part and a small anti-symmetric part, respectively, in bounded Lipschitz domains, quasi-convex domains, Reifenberg flat domains, domains, or (semi-)convex domains, in weighted Lebesgue spaces. The results given in this article improve the known results by weakening the assumption on the coefficient matrix. [ABSTRACT FROM AUTHOR]

Asthma, airway inflammation, airway remodeling, metformin, AMPK Corrigendum: Metformin Ameliorates Inflammation and Airway Remodeling of Experimental Allergic Asthma in Mice by Restoring AMPK Activity Keywords: asthma; airway inflammation; airway remodeling; metformin; AMPK EN asthma airway inflammation airway remodeling metformin AMPK 1 1 1 04/26/22 20220421 NES 220421 In the published article, there was an error regarding the affiliation for "Changgui Wu". [Extracted from the article]

The mechanical properties of both concrete and steel reinforcement, and the load-bearing capacity of reinforced concrete (RC) structures are well known to be temperature-sensitive, as demonstrated by the severe damage that major fires cause in buildings, followed—in extreme cases—by their collapse. Since in most cases RC structures survive a fire, retrofitting fire-damaged RC members is a hot subject today. In this paper, after a recall on the performance of RC beams and slabs in fire, different repair techniques are considered, among them externally bonded reinforcement, near surface-mounted fiber-reinforced polymers (FRP), bolted side plating, jacketing with high- and ultra-high performance concretes or mortars, and damaged-concrete replacement. Last but not least, the design equations aimed at evaluating the residual load-bearing capacity after repairing are also presented and discussed. [ABSTRACT FROM AUTHOR]

Purpose: Investigate the clinical/hematological characteristics of children infected with the Omicron variant of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) and identify an effective indicator to distinguish coronavirus disease 2019 (COVID-19) severity in children., Methods: A retrospective study was conducted through electronic medical records from pediatric patients. The demographic, clinical, and routine blood test (RBT) features of children diagnosed by real-time PCR for SARS-CoV-2 were collected., Results: Data of 261 patients were analyzed. The most common abnormality shown by RBTs was increased monocyte count (68%). Children had "mild-moderate" or "severe" forms of COVID-19. Prevalence of abnormal neutrophil count ( p  = 0.048), eosinophil count ( p  = 0.006), mean corpuscular volume ( p  = 0.033), mean platelet volume ( p  = 0.006), platelet-large cell ratio ( p  = 0.043), and red blood cell distribution width-standard deviation ( p  = 0.031) were significantly different in the two types. A combination of the neutrophil: lymphocyte ratio (NLR) and eosinophil count for diagnosing severe COVID-19 presented the largest AUC (0.688, 95% CI = 0.599-0.777; p  < 0.001), and the AUC increased with a decrease in age., Conclusions: Combination of the NLR and eosinophil count might be a promising indicator for identifying severe COVID-19 in children at infection onset., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (© 2024 Jin, Ma, Zhang, Wang, Geng, Geng, Zhang, Gao, Zhou, Li, Gou, Zhong, Li, Hou and Lu.)

Purpose: A large body of evidence has revealed that the sudden outbreak of public health emergencies induces dramatic effects on the mental health of the general public. We aimed to investigate the level of anxiety sensitivity and its risk factors in children and adolescents from northwest China during the COVID-19 pandemic lockdown in early 2020., Methods: A cross-sectional survey was conducted through the Wenjuanxing platform using a convenience sampling method between 18 and 26 February 2020. The self-designed questionnaire contained sociodemographic characteristics, factors associated with the COVID-19 pandemic, and the Childhood Anxiety Sensitivity Index (CASI) scale. The data from 1,091 valid questionnaires from students aged 9-17 years were analyzed using ANOVA, multiple linear regression, and binary logistic regression., Results: The average CASI scores were 11.47 ± 6.631, and 642 students (58.9%) had prominent anxiety sensitivity. Gender, education level, family members participating in anti-COVID-19 work, getting ill and needing medical help during the lockdown, feeling afraid or having heart palpitations on hearing things associated with COVID-19, believing that COVID-19 would have adverse impacts on themselves or their family in the future, and fear of infection were identified as significant factors for elevated levels of anxiety sensitivity ( p < 0.05). We established a multiple linear regression model for the anxiety sensitivity score. Risk factors found for anxiety sensitivity in children and adolescents during the COVID-19 lockdown included studying in secondary or high school, becoming ill during the pandemic, feeling afraid or experiencing rapid heartbeat or palpitations on hearing about the COVID-19 pandemic, thinking that COVID-19 would have an adverse impact on themselves or their family in the future, and fear of infection., Conclusions: During the COVID-19 pandemic and home quarantine, scores measuring the prevalence of anxiety sensitivity in children and adolescents from northwest China were elevated. We should develop measures that especially target possible risk factors to intervene against and prevent anxiety sensitivity in children and adolescents in both the current and future pandemics., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Jin, Ma, Zhang, Wang, Hao, Geng, Zhong, Li, Hou and Lu.)