Robust reliable guaranteed cost control for uncertain singular systems with time-delay

The robust reliable guaranteed cost control for uncertain singular delay systems with actuator failures and a given quadratic cost function is studied. The system under consideration involves constant time-delay and norm-bounded parameter uncertainties. The purpose is to design state feedback controllers which can tolerate actuator failure, such that the closed-loop system is stable, and the specified cost function has an upper bound for all admissible uncertainties. The sufficient conditions for the solvability of this problem are obtained by a linear matrix inequality （LMI） method. Furthermore, a numerical example is given to demonstrate the applicability of the proposed approach.

乳腺癌新辅助化疗后微钙化减少对肿瘤病理完全反应的预测

目的:探讨乳腺癌患者新辅助化疗(neoadjuvant chemotherapy,NAC)后影响微钙化(mcrocalcification,MC)改变的因素及MC减少与肿瘤病理完全反应(pathological complete response,pCR)的相关性。方法:收集2015年1月至2018年12月天津医科大学肿瘤医院215例乳腺癌患者的临床资料,分为范围改变组及数量改变组,评估影响MC改变的因素。根据MC是否减少进行分组,分为MC范围缩小组及MC数量减少组,分析不同分子分型中MC减少与pCR的相关性。采用受试者工作特征曲线(receiver operat?ing characteristic curve,ROC)评价乳腺X线摄影(mammography,MG)检查中MC减少对pCR敏感性、特异性的预测。结果:MC呈弥散分布,范围>2 cm,数量>20个患者更易发生MC减少。MC范围缩小组较非缩小组易发生pCR。MC数量减少组与非减少组比较差异无统计学意义,分子分型不是MC范围缩小及数量减少与pCR的影响因素。MC范围缩小组预测pCR的敏感度为77.78%、特异度为57.45%(P=0.0001)。结论:乳腺癌患者NAC后MC改变因素为MC范围、数量及分布,MC范围缩小患者的pCR率高,但MC范围缩小对预测pCR准确性较低,暂不推荐MG检查评估NAC后是否达到pCR。

Biomass Microcapsules with Stem Cell Encapsulation for Bone Repair

Bone defects caused by trauma,tumor,or osteoarthritis remain challenging due to the lack of effective treatments in clinic.Stem cell transplantation has emerged as an alternative approach for bone repair and attracted widespread attention owing to its excellent biological activities and therapy effect.The attempts to develop this therapeutic approach focus on the generation of effective cell delivery vehicles,since the shortcomings of direct injection of stem cells into target tissues.Here,we developed a novel core-shell microcapsule with a stem cell-laden core and a biomass shell by using all-aqueous phase microfluidic electrospray technology.The designed core-shell microcapsules showed a high cell viability during the culture procedure.In addition,the animal experiments exhibited that stem cell-laden core-shell microcapsules have good biocompatibility and therapeutic effect for bone defects.This study indicated that the core-shell biomass microcapsules generated by microfluidic electrospray have promising potential in tissue engineering and regenerative medicine.

A Vaccine Based on the Receptor-Binding Domain of the Spike Protein Expressed in Glycoengineered Pichia pastoris Targeting SARS-CoV-2 Stimulates Neutralizing and Protective Antibody Responses

In 2020 and 2021,severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),a novel coronavirus,caused a global pandemic.Vaccines are expected to reduce the pressure of prevention and control,and have become the most effective strategy to solve the pandemic crisis.SARS-CoV-2 infects the host by binding to the cellular receptor angiotensin converting enzyme 2(ACE2)via the receptor-binding domain(RBD)of the surface spike(S)glycoprotein.In this study,a candidate vaccine based on a RBD recombinant subunit was prepared by means of a novel glycoengineered yeast Pichia pastoris expression system with characteristics of glycosylation modification similar to those of mammalian cells.The candidate vaccine effectively stimulated mice to produce high-titer anti-RBD specific antibody.Furthermore,the specific antibody titer and virus-neutralizing antibody(NAb)titer induced by the vaccine were increased significantly by the combination of the double adjuvants Al(OH)_(3) and CpG.Our results showed that the virus-NAb lasted for more than six months in mice.To summarize,we have obtained a SARS-CoV-2 vaccine based on the RBD of the S glycoprotein expressed in glycoengineered Pichia pastoris,which stimulates neutralizing and protective antibody responses.A technical route for fucose-free complex-type N-glycosylation modified recombinant subunit vaccine preparation has been established.

Impacts of Four Invasive Asteraceae on Soil Physico-Chemical Properties and AM Fungi Community

Invasive Asteraceae are an important group of plants and might have universal impacts on invaded ecosystems. However, research data on the ecological impacts of specific plants are still lacking. Chromolaena odorata, Ageratina adenophora, Flaveria bidentis, and Mikania micrantha are four typical alien Asteraceae in China. The involvement of soil biota, in particular, the community structure of arbuscular mycorrhizal (AM) fungi in their invasion process was tested in present research. It was found that invasion by the four Asteraceae changed, to different extents, the nutrient levels in soils. Invasion by C. odorata, A. adenophora, and F. bidentis followed common patterns: 1) decreasing pH value;2) increasing the soil AM fungal diversity and species richness. Invasion by all four Asteraceae tested increased nitrogen pools and accelerated nitrogen fluxes with a decrease in the phosphorus pool, especially available phosphorus. It was suggested that mycorrhizal symbiosis might partially promote successful invasion of these Asteraceae by affecting the metabolism of phosphorus in soil. The impacts on soil ecosystems of these Asteraceae tested were also species-specific, and different invasion strategies were exhibited.

Hierarchically Inverse Opal Porous Scaffolds from Droplet Microfluidics for Biomimetic 3D Cell Co-Culture

With the advantages of better mimicking the specificity of natural tissues,three-dimensional(3D)cell culture plays a major role in drug development,toxicity testing,and tissue engineering.However,existing scaffolds or microcarriers for 3D cell culture are often limited in size and show suboptimal performance in simulating the vascular complexes of living organisms.Therefore,we present a novel hierarchically inverse opal porous scaffold made via a simple microfluidic approach for promoting 3D cell co-culture techniques.The designed scaffold is constructed using a combined concept involving an emulsion droplet template and inert polymer polymerization.This work demonstrates that the resultant scaffolds ensure a sufficient supply of nutrients during cell culture,so as to achieve large-volume cell culture.In addition,by serially planting different cells in the scaffold,a 3D co-culture system of endothelial-cellencapsulated hepatocytes can be developed for constructing certain functional tissues.It is also demonstrated that the use of the proposed scaffold for a co-culture system helps hepatocytes to maintain specific in vivo functions.These hierarchically inverse opal scaffolds lay the foundation for 3D cell culture and even the construction of biomimetic tissues.

Cutting Propagation Test of Shoots of Sapindus mukorossi Gaertn

In order to solve the problem of rapid propagation of Sapindus mukorossi Gaertn seedlings, research on the cutting propagation of S. mukorossi Gaertn was conducted. The results showed that the rooting rate of cuttings of the ten clones ranged from 30.9% to 83.0%. Among them, the rooting rate of cuttings of clones SM01 and SM06 was higher than that of other clones, and there were significant differences between different clones in the rooting rate of cuttings. The rooting rate of the semi-lignified shoots having two leaves could be improved significantly. The treatment of the cuttings by GGR6 solutions had significant effects on their rooting rate.

额外维存在性的理论探讨

是否存在超出我们生活的4维时空的额外维度是一个有趣而重要的问题.本文从理论角度探讨这一问题,先讨论了早期引力与电磁相互作用统一的5维卡鲁扎-克莱茵(Kaluza-Klein,KK)-理论,然后介绍了超对称和超引力与额外维的关联,最后介绍了弦理论和M-理论,并解释为何超弦理论本身的完善要求存在一个时空维度最大可以是11维的M-理论.至少从经典层面上,额外维对超对称和超引力来说仅仅是一种选择,不是必须的.目前,除4维N=8超引力理论有可能是一个自洽的量子引力理论,其他4维和高维的超引力理论紫外都有问题,需要考虑新的物理自由度,对应的紫外完善理论很可能就是弦/M-理论.弦理论对额外维的要求有所不同,其微扰量子自洽性要求额外维必须存在.例如,对超弦理论,时空必须是10维的.如果弦/M-理论的确是描述物质和相互作用的基本理论,那额外维就一定存在,同时需要对额外的空间维度作紧致化,且其尺度必须小于目前的实验限制.本文也讨论了一些相关唯象大额外维理论.

Microfluidic generation of egg-derived protein microcarriers for 3D cell culture and drug delivery

Microcarriers have a demonstrated value for biomedical applications,in particular for drug delivery and three-dimensional cell culture.Attempts to develop this technique tend to focus on the fabrication of functional microparticles by using convenient methods with innovative but accessible materials.Inspired by the process of boiling eggs in everyday life,which causes the solidification of egg proteins,we present a new microfluidic‘‘cooking"approach for the generation of egg-derived microcarriers for cell culture and drug delivery.As the egg emulsion droplets are formed with exquisite precision during the microfluidic emulsification,the resultant egg microcarriers present highly monodisperse and uniform morphologies at the size range of hundred microns to one millimeter.Benefiting from the excellent biocompatibility of the egg protein components,the obtained microcarriers showed good performances of cell adherence and growth.In addition,after a freezing treatment,the egg microcarriers were shown to have interconnected porous structures throughout their whole sphere,could absorb and load different kinds of drugs or other active molecules,and work as microcarrier-based delivery systems.These features point to the potential value of the microfluidic egg microcarriers in biomedicine.

Tofu-inspired microcarriers from droplet microfluidics for drug delivery

Microcarriers have attracted increasing interests in drug delivery. In order to develop this technique, it is prone to focus on the generation of functional particles through using simple approaches and novel but accessible materials. Here, inspired by the formation mechanism of tofu that through the mixing of soymilk and brine for cross-linking soybean proteins, we present novel soybean protein microcarriers by using microfluidic generation approach for drug delivery. Since the soybean protein droplets are generated by microfluidic emulsification method, the tofu microparticles present highly monodisperse and homogeneous morphologies. Because of the excellent biocompatibility of the soybean protein and the interconnected porous structures throughout the whole microparticles after freeze-drying, various kinds of drugs and active molecules could be absorbed and loaded in the microcarriers, which makes them versatile for drug delivery. It can be anticipated that the microfluidic-generated tofu microcarriers will have great potential in the biomedical field.

Responsive Inverse Opal Scaffolds with Biomimetic Enrichment Capability for Cell Culture

Three-dimensional(3D)porous scaffolds have a demonstrated value for tissue engineering and regenerative medicine.Inspired by the predation processes of marine predators in nature,we present new photocontrolled shrinkable inverse opal graphene oxide(GO)hydrogel scaffolds for cell enrichment and 3D culture.The scaffolds with adjustable pore sizes and morphologies were created using a GO and N-isopropylacrylamide dispersed solution as a continuous phase of microfluidic emulsions for polymerizing and replicating.Because of the interconnected porous structures and the remotely controllable volume responsiveness of the scaffolds,the suspended cells could be enriched into the inner spaces of the scaffolds through predator-like swallowing and discharging processes.Hepatocyte cells concentrated in the scaffold pores could form denser 3D spheroids more quickly via the controlled compression force caused by the shrinking of the dynamic scaffolds.More importantly,with a program of scaffold enrichment with different cells,an unprecedented 3D multilayer coculture system of endothelial-cellencapsulated hepatocytes and fibroblasts could be generated for applications such as liver-on-a-chip and bioartificial liver.It was demonstrated that the resultant multicellular system offered significant improvements in hepatic functions,such as albumin secretion,urea synthesis,and cytochrome P450 expression.These features of our scaffolds make them highly promising for the biomimetic construction of various physiological and pathophysiological 3D tissue models,which could be used for understanding tissue level biology and in vitro drug testing applications.

丝素蛋白反蛋白石结构微球用于肿瘤术后免疫治疗

恶性肿瘤的术后复发是导致其治疗失败的主要原因.本文介绍了一种利用丝素蛋白材料复制胶体晶体模板,制备新型丝素蛋白反蛋白石结构微球(SIOPs),并将其用于肿瘤的术后免疫治疗的方法.由于反蛋白石结构微球拥有大量尺寸均匀、相互连接的纳米孔洞,再加上丝素蛋白良好的生物相容性,制备的SIOPs不仅可以有效地负载大量抗肿瘤药物,还可以作为正常细胞粘附、生长和分化的三维支架,从而对术后创面部位的组织再生做出贡献.实验证明,所得的SIOPs能够有效负载抗体药物并使其在体内缓慢释放,进而达到募集免疫细胞攻击肿瘤细胞的作用.此外,抗体药物在SIOPs的制备过程中可不受外界影响并保持较高的生物活性.因此,这种新型的SIOPs不仅可以提高手术切除肿瘤后的治疗效果,还可以促进原位组织再生,在肿瘤免疫治疗方面具有极大的应用潜力,有望成为有效的肿瘤术后治疗新策略.

Bioinspired structural color particles with multi-layer graphene oxide encapsulated nanoparticle components

Because of the unique features of spherical symmetry,angle-independency,good monodispersity,controllable components and morphologies,structural color particles(SCPs)have found great significances in various fields such as sensing,monitoring,biological assays,etc.Here,inspired by the melanosome-derived bright structural colors and the self-adhesivity of mussels,we present a kind of bioinspired SCPs assembled from polydopamine(PDA)-adhered multi-layer graphene oxide(GO)encapsulated silica nanoparticles(SNs).It is demonstrated that compared with traditional SCPs,the designed particles possess brighter and more vibrant structural colors,and no complicated modification is required during the functionalization process due to the abundant inherent functional groups of GO.The resultant SCPs are verified to be capable for direct hybridization chain reaction and multiplexed nucleic acid assays.These properties indicate the promising prospects of our designed SCPs.

Localization of gravitino field on f(R)-thick branes

In this paper, we consider the localization of a five-dimensional gravitino field on f(R)-thick branes. We obtain the coupled chiral equations of the Kaluza-Klein(KK) modes of gravitinos with the gauge condition Ψ_z= 0. The chiral equations of a gravitino's KK modes are found to be almost identical to those of the Dirac fermion. However, their chiralities are exactly opposite. The chiral KK modes of gravitinos could be localized in some types of f(R)-thick branes on introducing a coupling term. We investigate the localization of a gravitino on three types of f(R)-thick branes through a Yukawa-like coupling term with background scalar fields. It has been shown that all the KK modes of gravitinos cannot be localized in the pure geometric f(R)-thick branes by adding a five-dimensional gravitino mass term. However, for the f(R)-thick branes generated by one or two background scalar fields, only the left-or right-handed zero mode could be localized in the branes, and the massive KK resonant modes are the same for both left-and right-handed gravitinos despite their opposing chiralities. All these results are consistent with those of the five-dimensional Dirac fermion except their chiralities, which may be an important sign to distinguish the gravitino field and the Dirac fermion field.