Effect of different bending shapes on thermal properties of flexible light-emitting diode filament

Heat dissipation is an important part of light-emitting diode(LED)filament research and has aroused constant concern.In this paper,we studied the thermal performance of flexible LED filament by numerical simulation and through experiment.The heat dissipation characteristics of spring-like structure flexible LED filament were computed by finite volume method,and it was found that the chip junction temperature was closely related to the pitch and the bending radius.The effect of inclination angle of lighting LED filament was discussed because it is relevant to the spring-like structure flexible LED filament in geometry.The results demonstrated that the temperature of the filament increases as the inclination angle improves.

Continuous preparation of strong and tough PVA nanocomposite fibers by mechanical stretching-assisted salting-out treatment

Polymer composite fibers with superior properties such as excellent combined strength and toughness and biocompatibility can be used in high-tech applications of braided protective devices and smart wearable,however the research of high-performance polymer composite fiber remains in the infant stage.Here we present a strategy to produce strong and tough anisotropic polymer nanocomposite fibers with orientedly aligned salt rods using mechanical stretching-assisted salting-out treatment.The prepared nanocomposite fibers have a tensile strength of up to 786±2.7 MPa and an elongation at break of 81%,and the anisotropic fibers exhibit good transmission of mechanical vibration in the longitudinal direction with high resolution.During the fabrication process,the salt builds up into oriented rods during the directional salting process,and the polymer is confined to the 150 nm domain between the rods after the solvent is completely evaporated,giving the nanocomposite fibers superior mechanical properties.The presented strategy can be applied to the continuous mass production of nanocomposite fibers and is also generalizable to other polymer nanocomposites,which could extend the applicability of nanocomposite fibers to conditions involving more demanding mechanical loading and mechanical vibration transmission.

基于天然多孔材料的双梯度结构设计负泊松比超材料

负泊松比超材料由于其优异的力学性能,包括优异的抗剪切性能、抗冲击性能、抗断裂性能、吸能隔振等,在个体防护和抗冲击、减振吸能等领域有着重要的应用价值,从而引起了科学家和工程师们极大的研究兴趣.大多数传统的负泊松比超材料通常基于单元胞体的拓扑结构设计,这类超材料通常不可避免地面临着由其复杂拓扑结构,特别是内凹多边形结构,所带来的设计、制备难题.迄今为止,尽管许多研究人员致力于开发新的负泊松比超结构和材料,但很少有研究能明确指出负泊松比超材料的设计指南或工作流程,更多的研究是基于研究人员的设计灵感和对特定胞元结构的计算机辅助优化.基于此,我们提出了一种受自然启发的负泊松比超材料设计策略,利用天然多孔材料所具有的独特双梯度结构,例如以松质骨和向日葵茎髓心作为生物模型,通过在多孔结构中引入双梯度变化即可得到负泊松比效应,从而制备负泊松比超材料.这种受自然启发的负泊松比超材料设计思路具有一定的普适性,可以扩展到具有常见凸多边形胞元的多孔结构中,基本胞元结构并不局限于特定的内凹多边形等常见的用来构造负泊松比超材料的结构和形状.

正/负泊松比的排斥效应诱导的复合水凝胶在低应变下的刚性响应

水凝胶作为承载组织的替代产品引起了广泛关注.然而,与能够通过有限的变形来承受复杂载荷的承载组织不同,传统的水凝胶由于其柔软的特性,无法在低应变状态下表现出刚性响应.基于承载组织的软硬组分之间的协同作用,我们设计了采用软基质(正泊松比)和硬框架(负泊松比)的复合水凝胶,其刚度分别比基质和框架高18.9和4.2倍.相反,结合软基质(正泊松比)和框架(正泊松比)的设计对刚度增强有限.通过有限元分析,揭示了软基质与框架之间正、负泊松比斥力作用的内在机理.本研究为今后设计基于软硬组分协同效应的复合水凝胶提供了思路.

Inhibition of lysine-specific demethylase 1(LSD1)prevented tumor growth and metastasis by downregulating PD-L1 expression in lung adenocarcinoma

Lysine-specific demethylase 1(LSD1),as a histone lysine demethylase,demethylates monomethyl and dimethyl of histone H3 on lysine 4(H3K4)and lysine 9(H3K9).Studies have reported that high LSD1 expression promotes cell proliferation,migration,and invasion by regulating chromatin morphology and gene expression,and is closely related to the development of non-small cell lung cancer(NSCLC).1 However,the underlying mechanism of LSD1 on cell proliferation and migration remains unclear.

Identification of ferroptosis as a novel mechanism for antitumor activity of natural product derivative a2 in gastric cancer

Ferroptosis is a type of cell death accompanied by iron-dependent lipid peroxidation,thus stimulating ferroptosis may be a potential strategy for treating gastric cancer,therapeutic agents against which are urgently required.Jiyuan oridonin A(JDA) is a natural compound isolated from Jiyuan Rabdosia rubescens with anti-tumor activity,unclear anti-tumor mechanisms and limited water solubility hamper its clinical application.Here,we showed a2,a new JDA derivative,inhibited the growth of gastric cancer cells.Subsequently,we discovered for the first time that a2 induced ferroptosis.Importantly,compound a2 decreased GPX4 expression and overexpressing GPX4 antagonized the anti-proliferative activity of a2.Furthermore,we demonstrated that a2 caused ferrous iron accumulation through the autophagy pathway,prevention of which rescued a2 induced ferrous iron elevation and cell growth inhibition.Moreover,a2 exhibited more potent anti-cancer activity than 5-fluorouracil in gastric canc er cell line-derived xenograft mice models.Patient-derived tumor xenograft models from different patients displayed varied sensitivity to a2,and GPX4 downregulation indicated the sensitivity of tumors to a2.Finally,a2 exhibited well pharmacokinetic characteristic s.Overall,our data suggest that inducing ferroptosis is the major mechanism mediating anti-tumor activity of a2,and a2 will hopefully serve as a promising compound for gastric cancer treatment.

Super-tough and strong nanocomposite fibers by flow-induced alignment of carbon nanotubes on grooved hydrogel surfaces

Nanocomposite fibers have attracted intensive attentions owing to their promising applications in various fields. However, the fabrication of nanocomposite fibers with super toughness and strong strength under mild conditions remains a great challenge. Here we present a facile flow-induced assembly strategy for the development of super-tough and strong nanocomposite fibers with highly ordered carbon nanotubes (CNTs), which can be induced by directional and fast flow on a grooved hydrogel surface. The prepared nanocomposite fibers show excellent mechanical properties, with a tensile strength up to 643±27 MPa and toughness as high as 77.3±3.4 MJ m^-3 at ultimate strain of 14.8±1.5%. This versatile and efficient flow-induced alignment strategy represents a promising direction for the development of high-performance nanocomposites for practical applications.

Magnetic-programmable organohydrogels with reconfigurable network for mechanical homeostasis

Synthetic materials with tunable mechanical properties have great potential in soft robotics and biomedical engineering.However,current materials are limited to the mechanical duality altering their mechanical properties only between soft and hard states and lack of consecutively programmable mechanics.Herein,the magnetic-programmable organohydrogels with heterogeneous dynamic architecture are designed by encasing oleophilic ferrofluid droplets into hydrogel matrix.As magnetic field increases,the mechanical properties of organohydrogels can be consecutively modulated owing to the gradual formation of chain-like assembly structures of nanoparticles.The storage modulus G'increases by 2.5 times when magnetic field goes up to 0.35 T.Small-Angle X-ray Scattering(SAXS)confirms the reconfigurable orientation of nanoparticles and the organohydrogels show reversible modulus switching.Besides,the materials also exhibit high stretchability,magnetic actuation behavior and effective self-healing capability.Furthermore,the organohydrogels are applied into the design of effectors with mechanical adaptivity.When subjected to serious external perturbations,the effector can maintain mechanical homeostasis by regulating modulus of organohydrogel under applied magnetic field.Such materials are applicable to homeostatic systems with mechanically adaptive behaviors and programmed responses to external force stimuli.

Valuable prognostic indicators for severe burn sepsis with inhalation lesion:age, platelet count, and procalcitonin

Background:Severe burn sepsis can lead to high mortality. We explored the valuable prognostic indicators for severe burn sepsis with inhalation lesion. Methods:Thirty-eight severe burn patients with sepsis who were admitted to the Third Affiliated Hospital of Soochow University from August 2014 to December 2017 were retrospectively analyzed. Among them, 22 patients were assigned to the death group and 16 patients to the survival group. Their general information, vital signs, and blood index including serum procalcitonin (PCT) and C-reactive protein (CRP) levels at admission, diagnosis of sepsis, and 1-week post-diagnosis of sepsis were compared. Results:Patients in the death group were older and had lower platelet count (PLT) at diagnosis of sepsis and 1-week post-diagnosis as well as higher PCT level at 1-week post-diagnosis than patients in the survival group (all p<0.05). According to receiver operating characteristic (ROC) curves, the above four indicators could be used to predict the prognosis, and the area under the curve (AUC) of PLT at diagnosis and 1-week post-diagnosis was larger (0.888 and 0.911), and PLT at diagnosis had the highest sensitivity and specificity (0.842 and 0.937). In addition, these patients were divided into two groups by the optimal cutoff age of 38 years. According to multivariate logistic regression analysis and COX regression analysis, only age group and PLT at diagnosis were statistically significant (all p<0.05). The risk of death in the older group was 28 times higher than that in the younger group, and the risk of death increased by 3%for each unit reduction in PLT at diagnosis. Moreover, age group was an independent factor affecting the patients' survival (β=?1.370, p=0.026). Considering the survival time after sepsis, the mortality risk was lower for patients in the older group than for patients in the younger group (hazard ratio (HR)=0.254, 95%confidence interval (CI) 0.076–0.851). Conclusion:Age, PLT at diagnosis of sepsis, and 1-week post-diagnosis as well as PCT level at 1-week post-diagnosis are indicators for the evaluation of prognosis of severe burn sepsis with inhalation lesion. Among them, PLT at diagnosis has the greatest prognostic value. In addition, age can predict the patients' mortality and survival time after sepsis.

On Bounded Positive(m,p)-Circle Domains

Let D be a bounded positive （m, p）-circle domain in Cu. The authors prove that if dim（Iso（D）^0） = 2, then D is holomorphically equivalent to a Reinhardt domain; if dim（Iso（D）^0）=4, then D is holomorphically equivalent to the unit ball in C^2. Moreover, the authors prove the Thullen＇s classification on bounded Reinhaxdt domains in C^2 by the Lie group technique.