High Energy Density Polymer Dielectrics Interlayered by Assembled Boron Nitride Nanosheets

Polymer dielectrics such as poly(vinylidene fluoride) (PVDF) have drawn tremendous attention in high energy density capacitors because of their high dielectric constant and ease of processing. However, the discharged energy density attained with these materials is restrained by the inferior breakdown strength and electric resistivity. Herein, PVDF composite films with a nanosized interlayer of assembled boron nitride nanosheets (BNNSs) that is aligned along the in‐plane direction are prepared through a simple layer‐by‐layer solution‐casting process. Compared to the pristine PVDF, the composite films show remarkably suppressed leakage current, resulting in a high breakdown strength and a superior energy density which are 136% and 275%, respectively, that of the pristine PVDF. The experimental results and computational simulations reveal that the compact and successive interlayer of assembled BNNSs can largely mitigate the local field distortion and block the propagation of electrical treeing, which is advantageous over the conventional dielectric polymer nanocomposites. Notably, unlike the previous dielectric polymer nanocomposites that are usually incorporated with a high volume fraction of nanofillers, i.e., 5–10 vol%, the present composites contain only an extremely low content of nanfillers, e.g., 0.16 vol%. These findings offer a novel paradigm for fabricating high energy density and high efficiency polymer dielectrics.     

Effects of glucanase treatment on the structure and mechanical properties of cell walls in the giant‐celled xanthophycean alga Vaucheria frigida

The cell wall of the tip‐growing cells of the giant‐cellular xanthophycean alga Vaucheria frigida is mainly composed of cellulose microfibrils (CMFs) arranged in random directions and the major matrix component into which the CMFs are embedded throughout the cell. The mechanical properties of a cell‐wall fragment isolated from the tip‐growing region, which was inflated by artificially applied pressure, were measured after enzymatic removal of the matrix component by using a protease; the results showed that the matrix component is involved in the maintenance of cell wall strength. Since glucose and uronic acid are present in the matrix component of Vaucheria cell walls, we measured the mechanical properties of the cell wall after treatment with endo‐1,3‐ß‐glucanase and observed the fine structures of its surfaces by atomic force microscopy. The major matrix component was partially removed from the cell wall by glucanase, and the enzyme treatment significantly weakened the cell wall strength without affecting the pH dependence of cell wall extensibility. The enzymatic removal of the major matrix component by using a protease released polysaccharide containing glucose and glucuronic acid. This suggests that the major matrix component of the algal cell walls contains both proteins (or polypeptides) and polysaccharides consisting of glucose and glucuronic acid as the main constituents.     

Beyond the epithelium: cadherin function in fibrous connective tissues

In fibrous connective tissues, fibroblasts are organized into syncytia, cellular networks that enable matrix remodeling and that are interconnected by intercellular adherens junctions (AJs). The AJs of fibroblasts are mediated by N-cadherin, a broadly expressed classical cadherin that is critically involved in developmental processes, wound healing and several diseases of mesenchymal tissues. In contrast to E-cadherin-dependent junctions of epithelia, the formation of AJs in fibrous connective tissues is relatively uncharacterized. Work over the last several years has documented an expanding list of molecules which function to regulate N-cadherin mediated junctions such as: Fer, PTP1B, cortactin, calcium, gelsolin, PIP5KIgamma, PIP2, and the Rho family of GTPases. We present an overview on the regulation of N-cadherin-mediated junction formation that highlights recent molecular advances in the field and rationalizes the roles of N-cadherin in connective tissue function.     

电针阴部神经刺激疗法联合Kegel盆底康复训练对产后压力性尿失禁患者盆底肌力、尿流动力学和生活质量的影响

摘要 目的：探讨电针阴部神经刺激疗法联合Kegel盆底康复训练对产后压力性尿失禁（SUI）患者盆底肌力、尿流动力学和生活质量的影响。方法：选取2019年6月~2021年11月期间于我院就诊的产后SUI患者109例,按照入院就诊奇偶顺序分为两组,其中对照组54例,接受Kegel盆底康复训练,研究组55例,接受电针阴部神经刺激疗法联合Kegel盆底康复训练。对比两组疗效、漏尿量、尿失禁程度、盆底肌力、尿流动力学和生活质量。结果：研究组的临床总有效率高于对照组（P<0.05）。两组治疗后盆底肌肌力各指标（手测肌力和Ⅰ类肌纤维最大值、Ⅱ类肌纤维平均值）均升高,且研究组高于对照组（P<0.05）。两组治疗后漏尿量、尿失禁程度评分均下降,且研究组低于对照组（P<0.05）。两组治疗后尿流动力学相关指标[腹压漏尿点压（AL-PP）、最大尿流率（Qmax）和最大尿道闭合压力（MUCP）]均升高,且研究组高于对照组（P<0.05）。两组治疗后尿失禁生活质量量表（I-QOL）各维度（限制性行为、心理影响、社交活动受限）评分及总分均升高,且研究组高于对照组（P<0.05）。结论：电针阴部神经刺激疗法联合Kegel盆底康复训练可有效改善产后SUI患者的盆底肌肌力和尿失禁情况,减少漏尿量,同时可促进尿流动力学恢复,进而提高患者的生活质量。     

Effects of a tongue training program in Parkinson's disease: Analysis of electrical activity and strength of suprahyoid muscles

ObjectiveTo assess the electrical activity of the suprahyoid muscle and the tongue pressure in a two-wing program of tongue strengthening in individuals with Parkinson's disease (PD).MethodsA pre-post-detraining design study included sixty PD patients assigned to two groups randomly. The experimental group (EG) performed tongue isometric pressure exercises using the Iowa Oral Performance Instrument with an increasing scheme of 5% load weekly and traditional tongue therapy for 8 weeks. The control group (CG) performed only traditional therapy. The electrical activity of suprahyoids was measured using surface electromyography (sEMG) during tongue-to-palate pressure. Four selected domains of the Swallowing Quality of Life Questionnaire (SWAL-QOL) mostly related to tongue strength were considered.ResultsThe experimental group showed increased sEMG values of suprahyoid muscles reaching statistically significant difference at the fourth week of tongue training, while the control did it at the eighth week. Experimental group showed significant improvements in tongue strength (d = 2.128; p = 0.000). Only controls showed detraining effect. Statistically significant difference within groups were found in one and three dimensions of the SWAL-QOL in the CG and EG, respectively.ConclusionAnalysis of electrical activity on suprahyoids muscles provided a better understanding of the changes underlying the outcomes of tongue strength gains obtained through a combined tongue strengthening exercises protocol in PD. Such protocol led not only to increased tongue strength but also to a better perceived swallowing function in PD subjects.     

Local cryostimulation acutely preserves maximum isometric handgrip strength following fatigue in young women

Several types of cryostimulation have been recently proposed to rapidly lower skin temperature therefore gaining a possible neuro/muscular recovery after strenuous exercise or, more generally, in sports. Local cryostimulation may be a viable and relatively portable tool to obtain physiological benefits in previously-efforted muscular districts. However, cohesive and standardized cryo-exposure protocols are lacking as well as the righteous procedure to efficaciously combine duration, treatments and temperature in relation to desirable effects on muscular strength. In this randomized-controlled study, fifty young women were tested for maximum isometric handgrip strength, before and after exhausting contractions.Following the fatiguing protocol, the intervention group (cryo, n = 25, 24.7 ± 2.5 years, BMI 21.7 ± 1.8 kg/m²) underwent a 6-min local cryostimulation (−160 °C) on the extensor-flexor muscles of the dominant arm, while control-matched peers sat rested in a thermo-neutral room (22 ± 0.5 °C). Handgrip tests were repeated at baseline (T0), after cryostimulation (T1), and 15 min after T1 (T2). Throughout the protocol, the AUC of the strength performance was significantly higher in the cryo- compared to control group (P = 0.006). In particular, following fatigue and cryostimulation, the cryo group preserved higher strength at T1 with respect to controls (26.8 ± 2.8 vs 23.9 ± 2.8 kg, Bonferroni's post-hoc, P < 0.01). Likewise, ventral and dorsal temperature, recorded with a thermal camera, were lower in cryo- than control group (P < 0.0001).In conclusion, a brief session of local cryostimulation may acutely preserve maximal isometric force in young women following a fatiguing protocol. These findings may have implications in orchestrating strategies of district muscular recovery.     

Great spotted cuckoo eggshell microstructure characteristics can make eggs stronger

Obligate avian brood parasites lay stronger eggs than their hosts or non‐parasitic relatives because they are rounder and have a thicker eggshell. Additionally, some other characteristics of the brood parasitic eggshells related to their microstructure such as size and orientation of calcite crystal units could also contribute to generating even stronger shells. An eggshell microstructure formed by small randomly oriented calcite crystal units can increase the robustness of the eggshells of birds. Here, the eggshell microstructure of avian brood parasites as well as their hosts have been characterized in detail, using X‐ray diffraction analyses to estimate the size and degree of orientation of calcite crystal units making the eggshell. Specifically, the brood parasitic great spotted cuckoo Clamator glandarius and two hosts (jackdaws Corvus monedula and magpie Pica pica) and one non‐host species (the pigeon, Columba livia domestica) were considered. Calcite crystal of the eggshell of the brood parasitic species was smaller and more randomly oriented than those of the eggshells of non‐parasitic species, which suggest that eggshell microstructure would contribute to explain why parasitic eggs are more resistant to breakage than those of their hosts.     

Strength exercise suppresses STZ-induced spatial memory impairment and modulates BDNF/ERK-CAMKII/CREB signalling pathway in the hippocampus of mice

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that has generated scientific interest because of its prevalence in the population. Studies indicate that physical exercise promotes neuroplasticity and improves cognitive function in animal models and in human beings. The aim of the present study was to investigate the effects of strength exercise on the hippocampal protein contents and memory performance in mice subjected to a model of sporadic AD induced by streptozotocin (STZ). Swiss mice received two injections of STZ (3 mg/kg, intracerebroventricular). After 21 days, they began physical training using a ladde. Mice performed this protocol for 4 weeks. After the last exercise training session, mice performed the Morris Water Maze test. The samples of hippocampus were excised and used to determine protein contents of brain-derived neurotrophic factor (BDNF), extracellular signal-regulated kinase-Ca²⁺ (ERK), calmodulin-dependent protein kinase (CAMKII) and cAMP-response element-binding protein (CREB) signalling pathway. Strength exercise was effective against the decrease in the time spent and distance travelled in the target quadrant by STZ-injected mice. Strength exercise was also effective against the reduction of mature BDNF, tropomyosin receptor kinase B and neuronal nuclear antigen (NeuN) hippocampal protein levels in STZ mice. The decrease in the hippocampal ratio of pERK/ERK, pCAMKII/CAMKII and pCREB/CREB induced by STZ was reversed by strength exercise. Strength exercise decreased Bax/Bcl2 ratio in the hippocampus of STZ-injected mice. The present study demonstrates that strength exercise modulated the hippocampal BDNF/ERK-CAMKII/CREB signalling pathway and suppressed STZ-induced spatial memory impairment in mice.     

Multiple drug resistance and strength of attachment to surfaces in Pseudomonas aeruginosa isolates

Aims: To investigate the presence of a relationship between the strength of attachment of Pseudomonas aeruginosa to stainless steel surfaces and their observed multiple drug resistance. Methods and Results: Multiple drug resistance of clinical and environmental isolates of Ps. aeruginosa was evaluated using disc diffusion method. The blot succession technique was used to quantify the strength of attachment of Ps. aeruginosa isolates. Different multiple drug–resistant Ps. aeruginosa isolates exhibited variable attachment strength. Although the highest multiple drug–resistant clinical isolate was shown to have the least attachment strength among clinical isolates, a weak correlation was found between attachment strength and multiple resistance among our investigated Ps. aeruginosa isolates. Conclusions: There is a weak correlation between multiple drug resistance and strength of attachment to stainless steel surfaces. Significance and Impact of the Study: Even low‐resistant Ps. aeruginosa could have the potential of attaching firmly to surfaces and forming biofilm.