Antimicrobial second skin using copper nanomesh

The functional support and advancement of our body while preserving inherent naturalness is one of the ultimate goals of bioengineering. Skin protection against infectious pathogens is an application that requires common and long-term wear without discomfort or distortion of the skin functions. However, no antimicrobial method has been introduced to prevent cross-infection while preserving intrinsic skin conditions. Here, we propose an antimicrobial skin protection platform copper nanomesh, which prevents cross-infectionmorphology, temperature change rate, and skin humidity. Copper nanomesh exhibited an inactivation rate of 99.99% for Escherichia coli bacteria and influenza virus A within 1 and 10 min, respectively. The thin and porous nanomesh allows for conformal coating on the fingertips, without significant interference with the rate of skin temperature change and humidity. Efficient cross-infection prevention and thermal transfer of copper nanomesh were demonstrated using direct on-hand experiments.

The functional support and advancement of our body while preserving the inherent naturalness is one of the ultimate goals of bioengineering (1–4). A functional layer is placed on the skin to complement the intrinsic biological and interactive functions (5, 6) and to add functions that do not yet exist (7–9). During use, the second skin layer should completely exploit its function and underlay skin functions without deforming the skin or interfering with the skin’s external interaction. Materials and structures need to be conformal and mechanically similar to the skin to minimize the distortion of natural sensations and movements. In addition, the air and heat transfer on the skin must be unimpeded to obtain a natural and comfortable wear fit (10).Body protection that requires common and long-term wear is an application in which both functionality and naturalness are important. As the outermost layer connecting our body to the environment, the skin is exposed to physical damage, hazardous chemicals, and infectious pathogens (11, 12). Therefore, we add a protective layer on the skin that blocks or filters out external contaminants. This entails the isolation and accumulation of biochemical compounds, which can lead to self-contamination and the subsequent cross-contamination/infection by interacting with other objects. In contrast to chemical contamination, which is not self-reproductive, the biological contamination of infectious microbes, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a considerable issue to be addressed.By containing an antimicrobial material on the surface of the skin protective layer, cross-infection can be prevented in the long term. Unlike temporary rinsing or disinfection, the use of antibacterial or antiviral substances such as chemical or natural disinfectants and metal nanomaterials inhibits the growth of microorganisms on the surface (13–17). These materials are embedded in a complete covering polymer layer, such as gloves (18, 19), to isolate and protect both the inner and outer surfaces from the infection. To add breathability to the textile especially for the mask (13, 20, 21), many antibacterial fibers have been developed based on these materials. Moreover, various skin-attachable platforms with antimicrobial properties have been developed for convenient usage in daily lives. Antimicrobial nanofibers with conformal attachment to the skin have been developed for drug delivery, wound healing (22, 23), and electrophysiology (24, 25). In addition, stretchable and antibacterial hydrogels have been developed to allow more natural skin movement in wound-healing applications (26–28).However, there has been no practical skin protective solution to prevent cross-infection while preserving intrinsic skin conditions such as surface morphology, thermal transfer, and skin humidity. The thickening of the additional skin layer frequently results in a significant modification of the surface morphology, heat transfer, and the corresponding sensation. Thin layers have limited performance in terms of antimicrobial duration and speed. The skin coverage of polymer or hydrogel film blocks the transfer of air, moisture, and heat. In addition, the antimicrobial performance is focused on the skin side rather than the external side that affects cross-infection. Voids owing to the stiffness of the film or fiber and morphological differences compared to the skin further limit conformality, heat transfer, and water/air permeability (29).Here, we propose an antimicrobial skin protection platform copper nanomesh, which prevents cross-infection while minimizing modification of intrinsic skin properties such as interfacial morphology, temperature change rate, and skin humidity. The thin thickness and porous structure of the nanomesh allow conformal attachment to the fingertips, regardless of the mechanical and structural variations of the fingerprints, nails, and interfaces. To impart antimicrobial properties, copper, one of the most well-known antimicrobial (nano)materials (30–33), was coated with maintaining the nanomesh structure (copper nanomesh, from here onward). The measured inactivation rates of copper nanomesh against Escherichia coli bacteria and influenza virus A (H1N1) were 99.99% within 1 min and 10 min, respectively. It was found that the nanomesh structure contributed to the acceleration of bacterial inactivation compared to the copper film. Furthermore, it exhibited high biocompatibility with the skin cells and stable antibacterial performance even after long-term use (more than 6 h), including water immersion (more than 1 h).In addition, we investigated the naturalness of the copper nanomesh compared to that of the copper film and conventional gloves. As confirmed using the artificial skin and fingerprint recognition, the proposed copper nanomesh exhibited a higher conformability compared to that of the copper film. The copper nanomesh showed a high hydrophobicity to block external contaminants in solution while having high gas permeability and maintaining the skin humidity in a safe range. Additionally, the insertion of copper nanomesh did not affect the temperature change rate, which is important to maintain the sensation and comfort fit of the skin. Finally, the copper nanomesh was compared to the glove by wearing on our hands and interacting with various real-life objects. Using the proposed copper nanomesh, we successfully achieved an effective prevention of cross-infection and less-hindered thermal recognition of objects.     

Inhibitory effects of the atypical antipsychotic,clozapine, on voltage-dependent K+ channels in rabbit coronary arterial smooth muscle cells

To investigate the adverse effects of clozapine on cardiovascular ion channels, we examined the inhibitory effect of clozapine on voltage-dependent K⁺ (Kv) channels in rabbit coronary arterial smooth muscle cells. Clozapine-induced inhibition of Kv channels occurred in a concentration-dependent manner with an half-inhibitory concentration value of 7.84 ± 4.86 µM and a Hill coefficient of 0.47 ± 0.06. Clozapine did not shift the steady-state activation or inactivation curves, suggesting that it inhibited Kv channels regardless of gating properties. Application of train pulses (1 and 2 Hz) progressively augmented the clozapine-induced inhibition of Kv channels in the presence of the drug. Furthermore, the recovery time constant from inactivation was increased in the presence of clozapine, suggesting that clozapine-induced inhibition of Kv channels is use (state)-dependent. Pretreatment of a Kv1.5 subtype inhibitor decreased the Kv current amplitudes, but additional application of clozapine did not further inhibit the Kv current. Pretreatment with Kv2.1 or Kv7 subtype inhibitors partially blocked the inhibitory effect of clozapine. Based on these results, we conclude that clozapine inhibits arterial Kv channels in a concentration- and use (state)-dependent manner. Kv1.5 is the major subtype involved in clozapine-induced inhibition of Kv channels, and Kv2.1 and Kv7 subtypes are partially involved.     

Phenotype of Asthma-COPD Overlap in COPD and Severe Asthma Cohorts

BackgroundAsthma and chronic obstructive pulmonary disease (COPD) are airway diseases with similar clinical manifestations, despite differences in pathophysiology. Asthma-COPD overlap (ACO) is a condition characterized by overlapping clinical features of both diseases. There have been few reports regarding the prevalence of ACO in COPD and severe asthma cohorts. ACO is heterogeneous; patients can be classified on the basis of phenotype differences. This study was performed to analyze the prevalence of ACO in COPD and severe asthma cohorts. In addition, this study compared baseline characteristics among ACO patients according to phenotype.MethodsPatients with COPD were prospectively enrolled into the Korean COPD subgroup study (KOCOSS) cohort. Patients with severe asthma were prospectively enrolled into the Korean Severe Asthma Registry (KoSAR). ACO was defined in accordance with the updated Spanish criteria. In the COPD cohort, ACO was defined as bronchodilator response (BDR) ≥ 15% and ≥ 400 mL from baseline or blood eosinophil count (BEC) ≥ 300 cells/μL. In the severe asthma cohort, ACO was defined as age ≥ 35 years, smoking ≥ 10 pack-years, and post-bronchodilator forced expiratory volume in 1 s/forced vital capacity < 0.7. Patients with ACO were divided into four groups according to smoking history (threshold: 20 pack-years) and BEC (threshold: 300 cells/μL).ResultsThe prevalence of ACO significantly differed between the COPD and severe asthma cohorts (19.8% [365/1,839] vs. 12.5% [104/832], respectively; P < 0.001). The percentage of patients in each group was as follows: group A (light smoker with high BEC) – 9.1%; group B (light smoker with low BEC) – 3.7%; group C (moderate to heavy smoker with high BEC) – 73.8%; and group D (moderate to heavy smoker with low BEC) – 13.4%. Moderate to heavy smoker with high BEC group was oldest, and showed weak BDR response. Age, sex, BDR, comorbidities, and medications significantly differed among the four groups.ConclusionThe prevalence of ACO differed between COPD and severe asthma cohorts. ACO patients can be classified into four phenotype groups, such that each phenotype exhibits distinct characteristics.     

富氧水对高原移居青年心肺功能的影响

目的：探讨在高原服用富氧水对移居青年心肺功能的影响。方法：对进驻海拔3700m1年的10名青年在服用富氧水前和服用富氧水（每次500mL,一日2次）15天后分别用EGM-II型踏车功量计做坐位踏车运动,初始负荷功率为50W,每3min递增50W,以60r/min连续踏车至200W,3min后终止。用直线回归法计算每位受试者功率200W时的心率（HR）及血氧饱和度（SaO2）,记录运动终止5min后恢复HR,按公式计算心功能指数。结果：服用富氧水15天后,心功能指数增高,功率200W时SaO2增高;功率200W时的HR和运动终止5min恢复HR降低,差别有非常显著性意义（P〈0.01）。结论：服用富氧水能提高高原移居青年的心肺功能。     

一种新的T细胞相关分子IBP表达水平定量检测方法的建立

目的 建立一种定量检测IBP表达水平的方法 ,为研究IBP在免疫细胞分化以及在免疫性疾病当中的作用奠定基础.方法 利用反转录PCR和PCR技术获得目的 基因和内参基因片段,构建重组质粒,以重组质粒为标准品,建立实时PCR标准曲线;测定外周血白细胞IBP和β-actin表达水平.以β-actin为内参照,均一化检测结果 .结果 重组质粒的阳性克隆经PCR扩增,0.8%琼脂糖凝胶电泳鉴定,目的 基因片段插入载体内;建立起实时PCR标准曲线.检测20例正常人全血标本,得到比较稳定的检测结果 .结论 成功建立了用实时PCR定量检测IBP mRNA表达水平方法 ,为进一步研究IBP奠定了基础.     

Total arch repair versus hemiarch repair in the management of acute DeBakey type I aortic dissection

Objective: In acute DeBakey type I aortic dissection, it is still controversial whether to perform extended aortic replacement to improve long-term outcome or to use a conservative strategy with ascending aortic and hemiarch replacement to palliate a life-threatening condition. Methods: Between 1999 and 2009, 188 consecutive patients (93 women; mean age, 57.4 ± 11.7 years) with acute DeBakey type I aortic dissection underwent hemiarch (Hemiarch group; n = 144) or total arch replacement (Total arch group; n = 44) in conjunction with ascending aorta replacement. Clinical outcomes were compared after adjustment for baseline characteristics using inverse-probability-of-treatment weighting. Results: Median follow-up was 47.5 months (range 0–130.4 months) and was 92.0% (n = 173) complete. Five-year unadjusted survival and permanent-neurologic-injury-free survival rates were 65.8 ± 8.3% and 43.1 ± 9.7% in the Total arch group, and 83.2 ± 3.3% and 75.2 ± 4.0% in the Hemiarch group, respectively (P = 0.013 and <0.001). After adjustment, the Total arch group patients were at greater risks of death (hazard ratio (HR) 2.38, 95% confidence interval (CI) 1.21–4.67; P = 0.012), and permanent neurologic injury (HR 3.25, 95% CI 1.31–8.04; P = 0.011) compared to the Hemiarch group patients. The risks of the re-operation for aortic pathology or distal aortic dilatation (>55 mm) were similar for both groups (HR 0.33, 95% CI 0.08–1.43; P = 0.14). Conclusions: Total arch repair was associated with greater morbidity and mortality compared with hemiarch repair in acute DeBakey type I aortic dissection. Rates of aortic re-operation or aortic dilatation were not significantly different between the two surgical strategies. These findings support a conservative surgical approach to circumvent this life-threatening situation.     

三康胶囊对高原移居青年体力作业效率的影响

目的探讨在高原服用三康胶囊对移居青年体力作业效率的影响。方法对进驻海拔3 700 m 1年的10名青年在服药前和服药15d后分别用EGM-Ⅱ型踏车功量计做坐位踏车运动,初始负荷功率为50 W,每3 m in递增50 W,以60 r/m in连续踏车至200 W 3 m in后终止。用直线回归法计算每位受试者的PMC170,HR90w、功率200 W时的HR及SaO2,运动终止5 m in后恢复HR,按公式计算心功能指数。结果服药后各项检测指标较服药前均有非常显著性差异(P<0.01)。结论服用三康胶囊能明显提高高原移居青年的体力作业效率。     

海拔1400m某部官兵睡眠呼吸暂停低通气综合征患病率调查

目的调查某部官兵睡眠呼吸暂停低通气综合征(SAHS)的患病率,为进一步了解移居不同海拔高度不同时间人群的患病情况提供参照,并为制定该病的防治策略提供依据。方法采用整群抽样的方法对驻守海拔1 400 m的某部官兵进行睡眠问卷调查,根据打鼾程度及日间嗜睡评分保守估计人群SAHS患病率。结果在调查的348人中打鼾的发生率为39.08%,中度打鼾者占5.17%,无重度鼾症患者。吸烟和饮酒与打鼾程度相关。有高原接触史的被调查者打鼾发生率高于未曾上过高原者(χ2=7.122,P=0.028)。不同程度的打鼾患者,日间的嗜睡评分有显著性差异(F=3.689,P=0.013)。结论如果仅依据日间Epworth嗜睡量表(ESS)评分≥9分为标准,保守估计驻守海拔1 400 m某部官兵的SAHS患病率为4.02%,打鼾及SAHS是严重危害健康的疾病之一,但未引起人们的重视,需要搞好宣传教育工作。     

Three-Point Bending Properties of Hybrid Multi-Materials Using Adhesive Bonding Dependent on Strength Difference between Steel and Aluminum

The mechanical behaviors of two multi-materials, DP590 (steel sheet)–A356 (cast aluminum alloy) and SS330 (steel sheet)–A5052 (aluminum sheet), were studied. A structural adhesive was used for the joining of steel and aluminum at adhesion strengths of 10, 22, and 30 MPa. To demonstrate that the three-point bending properties depend on the difference in strength between steel and aluminum and adhesion strength, optical microscopy (OM), scanning electron microscopy (SEM), and finite-element analysis (FEA) were performed. According to the results of the bending tests on both multi-materials under the same stacking conditions, the flexural stress increased with the improvement in the adhesion strength until interface separation or aluminum fracture. At the same adhesion strength, the DP590 (lower)–A356 (upper) and SS330 (upper)–A5052 (lower) configurations exhibited a tendency to decrease in the sudden stress drop due to aluminum fracture and interface separation. The bending results were analyzed through the FEA and the stress distribution as a function of the stacking and adhesion strength was confirmed.