Metal-insulator crossover in monolayer MoS2.

We report on transport measurements in monolayer MoS2devices, close to the bottom of the conduction band edge. These devices were annealedin situbefore electrical measurements. This allows us to obtain good ohmic contacts at low temperatures, and to measure precisely the conductivity and mobility via four-probe measurements. The measured effective mobility up toµeff= 180 cm2V-1s-1is among the largest obtained in CVD-grown MoS2monolayer devices. These measurements show that electronic transport is of the insulating type forσ≤ 1.4e2/handn≤ 1.7 × 1012cm-2, and a crossover to a metallic regime is observed above those values. In the insulating regime, thermally activated transport dominates at high temperature (T> 120 K). At lower temperatures, conductivity is driven by Efros-Schklovkii variable range hopping in all measured devices, with a universal and constant hopping prefactor, that is a clear indication that hopping is not phonon-mediated. At higher carrier density, and high temperature, the conductivity is well modeled by the Boltzmann equation for a non-interacting Fermi gas, taking into account both phonon and impurity scatterings. Finally, even if this apparent metal-insulator transition can be explained by phonon-related phenomena at high temperature, the possibility of a genuine 2D MIT cannot be ruled out, as we can observe a clear power-law diverging localization length close to the transition, and a one-parameter scaling can be realized.

Insulin Resistance-Varying Associations of Adiposity Indices with Cerebral Perfusion in Older Adults: A Population-Based Study.

OBJECTIVES: Excessive accumulation of adipose tissue may accelerate brain aging, but the underlying mechanisms are poorly understood. Several adiposity indices were proposed to assess obesity, while their linkage with brain health in older adults remained unclear. Here we aimed to examine the associations of adiposity indices with global and regional cerebral blood flow (CBF) in older adults, while considering insulin resistance. DESIGN: This was a cross-sectional population-based study that included older adults derived from the baseline participants in the ongoing Multimodal Interventions to Delay Dementia and Disability in rural China (MIND-China) study. SETTING AND PARTICIPANTS: The study included 103 Chinese rural-dwelling older adults (age≥60 years; 69.9% women) who underwent brain magnetic resonance imaging scans. METHODS: We estimated eight adiposity indices based on anthropometric measures. We automatically quantified global and regional CBF using the arterial spin labeling scans. Insulin resistance was assessed using the triglyceride-glucose index and then dichotomized into high and low levels according to the median. Data were analyzed using general linear model and voxel-wise analysis. RESULTS: Of the eight examined adiposity indices, only higher waist-to-height ratio (WHtR) and body roundness index (BRI) were associated with reduced global CBF (multivariable-adjusted ß-coefficients and 95%CI: -1.76; -3.25, -0.27 and -1.77; -3.25, -0.30, respectively) and hypoperfusion in bilateral middle temporal gyri, angular gyri and superior temporal gyri, left middle cingulum and precuneus (P<0.05). There were statistical interactions of WHtR and BRI with levels of insulin resistance on CBF, such that the significant associations of higher WHtR and BRI with lower global and regional CBF existed only in people with high insulin resistance (P<0.05). CONCLUSION: Higher WHtR and BRI are associated with cerebral hypoperfusion in older adults, especially in people with high insulin resistance. This may highlight the pathological role of visceral fat in vascular brain aging.

[Effect of perioperative accelerated rehabilitation management program for children with congenital spinal deformity].

Objective: To explore the perioperative therapeutic effect of enhanced recovery after surgery (ERAS) in children with congenital spinal deformity and summarize the clinical experience. Methods: Fifty-nine pediatric patients with congenital spinal deformities admitted to Beijing Children's Hospital from May 2020 to January 2021 were included in this study, and all patients underwent posterior spinal osteotomy orthopedic implant fusion with internal fixation. There were 22 males and 37 females, aged (7.4±4.1) years. Patients were divided into ERAS group (n=29) and control group (n=30) according to the management model. Patients in the ERAS group were managed with an accelerated recovery management model during the perioperative period, which mainly included: high protein diet, shortened fasting time, optimized anesthesia protocol, and multimodal analgesia. Patients in the control group received the traditional perioperative management model. The indexes of surgery, diet, pain score and laboratory tests were compared between the two groups. Results: All patients completed the surgery successfully. The mean temperature and pain scores of patients in the ERAS group were lower than those in the control group at 3 days postoperatively (P<0.05). The time to exhaustion and defecation in the ERAS group was (1.0±0.8) d and (2.5±0.9) d postoperatively, both significantly earlier than those in the control group ((3.4±0.8) d and (4.0±1.1) d) (both P<0.05). C-reactive protein was 38(8,46) mg/L in patients of the ERAS group on the day 3 postoperatively, which was significantly lower than that in the control group 47(22,93) mg/L (P=0.023). The hemoglobin level on postoperative day 3 was (110.7±9.6) g/L in the ERAS group, which was significantly higher than that in the control group ((104.5±11.4) g/L) (P=0.029). Postoperative complications occurred in 8(27.6%) and 9(30.0%) patients in the ERAS and control groups, respectively (P=1.000), with mild abdominal pain and bloating being the most common complications in both groups, most of which were not treated specifically. Conclusion: ERAS is a safe and effective perioperative management mode for children with congenital spinal deformity. Compared with the traditional method, it can significantly improve the treatment efficiency and deserve clinical application.

Regulation of KDM2B and Brg1 on Inflammatory Response of Nasal Mucosa in CRSwNP.

Chronic nasal sinusitis with nasal polyps (CRSwNP) is a reversible nasal mucosal remodeling disease caused by persistent inflammation and structural changes in chronic nasal mucosa. Although there have been many studies on the inflammation of the nasal mucosa epithelium, the mechanism remains unclear. Our study found that H3K4me3 histone demethylase KDM2B (also known as JHDM1B) and transcriptional regulator Brg1 (also called SNF2-ß or Smarca4) were significantly decreased in nasal mucosa of CRSwNP patients, and they were positively correlated. Brg1 and KDM2B co-localize in the epithelial cells of nasal mucosa. We used poly(I:C)-treated nasal mucosal epithelial cells (HNECs) to find that the expression of KDM2B and Brg1 was also decreased, and the main expression position transferred from the nucleus to the nuclear membrane. We used small interfering RNA to knock down the expression of KDM2B and Brg1 in nasal epithelial cells. It was interesting to find that the decreased expression of KDM2B and Brg1 produced similar effects to that of poly(I:C)-treated cells, which could promote inflammatory response of nasal mucosal epithelial cells. And Brg1 appears to play a role in KDM2B regulating gene promoters of IL-6 and TNF-α inflammatory. This study shows that KDM2B and Brg1 may have an inhibitory effect on the development of CRSwNP nasal mucosal epithelial inflammation. This study will provide a new perspective for gene targeting therapy of CRSwNPs.

[Short term effect of PM(2.5) on cardiovascular mortality in residents in Changping district, Beijing].

Objective: To make a quantitative evaluation on the short term effect of particulate matter with aerodynamic diameter no more than 2.5 µm (PM(2.5)) on cumulative excess mortality rate (CER) and years of life lost (YLL) in residents in Changping district of Beijing. Methods: The death data in local residents, daily mortality, meteorology data and air pollution data (PM(2.5), SO(2) and NO(2) concentrations) in Changping from 2014 to 2017 were collected. Distributed lag non-linear model was used to assess the age and gender specific cumulative lag effects of PM(2.5) on cardiovascular CER and daily YLL in Changping. Results: The effects of PM(2.5) on cardiovascular CER and YLL were obvious on lag 7 days and lag 9 days, respectively, peaking on day 14, and lasting for 21 days. On lag0-21 days, for a 10 µg/m(3) increase in PM(2.5), the population based CER of cardiovascular disease death was 0.021% (95%CI: 0.004%-0.038%), and the YLL was 1.47 (95%CI: 0.23-2.70) years. Greater PM(2.5) effect were observed in males and the elderly. Conclusion: PM(2.5) increased the risk of cardiovascular disease death and YLL.

Micro124-mediated AHR expression regulates the inflammatory response of chronic rhinosinusitis (CRS) with nasal polyps.

MicroRNAs represent a component of the innate immune responses that can restrain inflammatory signaling, miR124 is an important member of inflammation-associated miRNAs, and abnormal miR124 expression is observed in many inflammatory diseases and immune disorders. However, the role and signaling pathways of miR124 in chronic rhinosinusitis with nasal polyps (CRSwNPs) have not been studied in detail. The aryl hydrocarbon receptor (AHR) is a ligand-inducible transcription factor that is highly conserved in evolution and plays important roles in the inflammatory response process. In our study, we describe the role of miR124 in the inflammatory response of CRS with nasal polyps. We found that the expression of miR124 was decreased in nasal polyps, and negatively correlated with the expression of AHR. MiR124 can inhibit AHR expression by directly target 3' untranslated region (3'-UTR) of AHR. To further investigate the relationship between miR124, AHR and CRS inflammatory response, we transfect HNEpC cells with miR124 mimic, miR124 inhibitors or siRNA of AHR, then all the results showed that miR124 could regulates cellular inflammatory response through negatively regulating AHR expression. This study demonstrated that the regulation of AHR expression by miR124 is critical to the development of inflammatory response in CRSwNPs.

Detection and differentiation of wild-type and vaccine strains of canine distemper virus by a duplex reverse transcription polymerase chain reaction.

Canine distemper virus (CDV) is the cause of canine distemper (CD) which is a severe and highly contagious disease in dogs. In the present study, a duplex reverse transcription polymerase chain reaction (RT-PCR) method was developed for the detection and differentiation of wild-type and vaccine strains of CDV. Four primers were designed to detect and discriminate the two viruses by generating 638- and 781-bp cDNA products, respectively. Furthermore, the duplex RT-PCR method was used to detect 67 field samples suspected of CD from Guangdong province in China. Results showed that, 33 samples were to be wild-type-like. The duplex RT-PCR method exhibited high specificity and sensitivity which could be used to effectively detect and differentiate wild-type and vaccine CDV, indicating its use for clinical detection and epidemiological surveillance.

Changes of serum brain-derived neurotrophic factor in children with obstructive sleep apnoea-hypopnoea syndrome following adenotonsillectomy.

Children with obstructive sleep apnoea syndrome (OSAS) have substantial cognitive functional morbidity. Brain-derived neurotrophic factor (BDNF) is a key mediator of memory and cognition, but its regulation in OSAS is unknown. Circulating BDNF, transforming growth factor-ß(1) and 5-hydroxytryptamine levels, cognitive ability and overnight polysomnography were evaluated in 44 children with newly-diagnosed OSAS and in 26 healthy children. All parameters were monitored pre-operatively and at 3, 6 and 12 months after adenotonsillectomy. Pre-operative cognitive ability and sleep parameters were significantly poorer in children with OSAS compared with controls, but BDNF levels were similar. At 3 months post-operation, serum BDNF concentrations decreased, but cognitive ability and sleep parameters remained deficient. At 6 months post-operation, serum BDNF levels, sleep parameters and cognitive ability had improved and, by 12 months, there were no differences between the two groups. It is concluded that adenotonsillectomy can rapidly normalize sleep parameters and improve the cognitive ability of children with OSAS, by regulating the circulating level of BDNF.

Expression of c-kit protein and mutational status of the c-kit gene in osteosarcoma and their clinicopathological significance.

We examined c-kit protein expression and mutations of the c-kit gene in 40 human osteosarcoma samples to their relationship with clinicopathology and prognosis of the disease. The expression of c-kit protein was evaluated by immunohistochemistry and single-strand conformational polymorphism was performed to evaluate c-kit gene mutations in exons 11 and 17. Expression of c-kit protein occurred in 25 (62.5%) osteosarcoma samples. Patients with osteosarcomas with higher c-kit protein expression levels were significantly more likely to experience local disease recurrence and had a significantly lower survival time than patients with lower c-kit expression. We found no evidence of mutations in exons 11 or 17. This study suggests that c-kit protein expression might serve as a prognostic marker for osteosarcoma, however exons 11 and 17 might not be suitable targets for osteosarcoma treatments based on suppression of c-kit tyrosine kinase activity.

Type II pneumocyte-CD8+ T-cell interactions. Relationship between target cell cytotoxicity and activation.

CD8+ T-cell responses play an important role in the clearance of respiratory virus infection, but may also contribute to lung injury in the process. The effector mechanisms involved in viral clearance and associated lung injury include both cytolytic and noncytolytic effector functions. Previously we have shown that CD8+ T-cell recognition of alveolar epithelial cells triggers chemokine expression by the epithelial cell and that this plays an important role in the inflammatory infiltration that ensues in the context of T cell-mediated injury (Zhao and colleagues, J. Clin. Invest. 2000;106:R49-R58). In the present study we sought to understand the relationship between alveolar cell cytotoxicity and chemokine expression, both of which occur as a result of CD8+ T-cell antigen recognition. Alveolar epithelial cells efficiently process and present overlapping viral epitopes, and CD8+ T-cell recognition of these class I major histocompatibility complex-restricted epitopes resulted in cytotoxicity of the alveolar cells by both wild-type and perforin-deficient T cells. However, the contribution of perforin-mediated lysis to the total cytotoxicity of alveolar cells by CD8+ T cells was minimal, and the majority of the lysis was attributable to tumor necrosis factor-alpha expressed by the T cell. CD8+ T-cell recognition also led to activation of nuclear factor-kappaB in the alveolar epithelial target cells, at levels inversely proportional to the effector/target (E:T) ratio. Finally, at varying E:T ratios, we demonstrated an inverse relationship between alveolar cell cytotoxicity and monocyte chemotactic protein-1 expression, both of which occur as a result of T-cell recognition. These findings may have important ramifications in understanding the relationship between viral clearance and lung injury.

[Studies on the arbutin biosynthesis by hairy root of Panax ginseng C.A. Mayer].

OBJECTIVE: To study basic conditions for biosynthesis arbutin by the hairy root of Panax ginseng. METHOD: Based on the content of arbutin and the biotransformation rate of hydroquione, these conditions such as the culture stage, the lasting time and the concentration of hydroquione fitting for biosynthesis were found. RESULT: After cultured for 22 days, transferred in fresh B5 medium having 2 mmol.L-1 hydroquione, the hairy root biotransformated hydroquione into arbutin in 24 hours, the bioconversion rate was 89.0% and the content of arbutin in dry root was 13.0%. CONCLUSION: Arbutin, was which never found in the genus of Panax ginseng, can be biosynthesized by the hairy root of Panax ginseng.

Alveolar epithelial cell chemokine expression triggered by antigen-specific cytolytic CD8(+) T cell recognition.

CD8(+) T lymphocyte responses are a critical arm of the immune response to respiratory virus infection and may play a role in the pathogenesis of interstitial lung disease. We have shown that CD8(+) T cells induce significant lung injury in the absence of virus infection by adoptive transfer into mice with alveolar expression of a viral transgene. The injury is characterized by the parenchymal infiltration of host cells, primarily macrophages, which correlates with physiologic deficits in transgenic animals. CD8(+) T cell-mediated lung injury can occur in the absence of perforin and Fas expression as long as TNF-alpha is available. Here, we show that the effect of TNF-alpha expressed by CD8(+) T cells is mediated not exclusively by cytotoxicity, but also through the activation of alveolar target cells and their expression of inflammatory mediators. CD8(+) T cell recognition of alveolar cells in vitro triggered monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-2 (MIP-2) expression in the targets, which was mediated by TNF-alpha. Antigen-dependent alveolar MCP-1 expression was observed in vivo as early as 3 hours after CD8(+) T cell transfer and depended upon TNF-R1 expression in transgenic recipients. MCP-1 neutralization significantly reduced parenchymal infiltration after T cell transfer. We conclude that alveolar epithelial cells actively participate in the inflammation and lung injury associated with CD8(+) T cell recognition of alveolar antigens.