In the early days of space flight,space motion sickness and spatial disorientation were always essential medical problems in space medicine.Either of them was closely connected with visual and vestibular system in its development.Nowadays some progresses were made in the researches about brain cognitive function changes during visual or vestibular stimulation,but the effects of visual-vestibular interaction on the brain cognitive processing are still under exploration.Lots of research techniques have been used in cognitive explorations,the brain event-related potentials(ERP) with its high time resolution is an objective and convenient means.In this article,the anatomic bases of visual,vestibular system and their projection to cortex,research progresses in visual cognition explored with ERP and current phenomena about the effects of visual-vestibular interaction on brain cognitive processing were reviewed.Research directions about visual-vestibular interaction on cognitive processing were put forward in order to provide reference for future studies.

Objective: According to the medical system reform’s requirement of “strengthening supervision, increasing the public health investment, reforming the compensation mechanism of public hospital, establishing public hospital performance evaluation and incentive system”, public hospitals should continue to reform its management system optimization, performance appraisal is the core content of hospital internal reform performance appraisal method, which is an important guarantee for the results of hospital performance evaluation. Methods: The study on the assessment methods of hospital performance, use “public hospital”, “performance” and“performance evaluation” as the keywords to search the Chinese HowNet and Wanfang database retrieval and 142 articles; by reading the whole passage and the method of stratified sampling, the common performance appraisal method are used to collect and collate, eventually the assessment method of hospital performance of 32 Chinese literature references are included in the study. Results:Summarize the evaluation methods of hospital performance application condition advantages, disadvantages and present situation, and establish a set of performance evaluation methods with the management of public hospitals more perfect, scientific and detailed theoretical basis. Conclusion: In the process of the medical system reform, according to the characteristics of hospitals, to choose suitable and effective performance appraisal methods to help the performance management in hospital, and receive more economic benefits while maximize social benefits.

Ansamycins, such as rifamycin and ansamitocin, usually consist of a group of structural similar components. Geldanamycin, a benzenic ansamycin, has been found to consist of four structural similar components. We analyzed the geldanamycin (GDM) preparation from Streptomyces hygroscopicus 17997 by LC-ESI(+)-MS/MS, and discovered five novel and one known GDM analogues in trace amounts. Based on the ESI(+)-MS/MS spectra of these GDM analogues, and the present understanding of GDM biosynthesis, we proposed the possible chemical structures of these GDM analogues. Three novel GDM analogues, all having the same molecular formula of C29H42N2O10, were GDM biosynthetic derivatives with one of the three C-C double bonds between C2-C3, C4-C5 and C8-C9 in GDM changed to mono-hydroxylated C-C single bond. The other two novel GDM analogues, having the same molecular formula of C28H38N2O8, were 17(or 12, or 4)-desmethoxylgeldanamycin and 4,5-dihydro-10,11-dehydrate-17-desmethyl-17-hydroxylgeldanamycin, respectively. The known GDM analogue, having the molecular formula of C29H42N2O9, was 4, 5-dihydrogeldanamycin, an intermediate in GDM biosynthesis. The discovery of novel GDM analogues provided us new insights in understanding the biosynthetic details of GDM, and clues of obtaining GDM derivatives by gene-disruption and combinatorial biosynthesis.
Anti-Bacterial Agents ; chemistry ; Benzoquinones ; analysis ; chemistry ; Chromatography, Liquid ; methods ; Lactams, Macrocyclic ; analysis ; chemistry ; Tandem Mass Spectrometry ; methods

Objective: To understand the epidemic trend of tobacco use among junior middle school students in Shunyi District of Beijing in recent 5 years, and to provide scientific basis for formulating adolescent tobacco control strategies and intervention measures. Methods: The two stage sampling method was used to survey 3 junior middle school schools randomly selected from Shunyi District, Beijing, in November 2013, December 2015 and November 2017. The number of students surveyed each year was 1 520, 1 404 and 1 467 respectively. Results: A total of 4 500 questionnaires were distributed and 4 391 questionnaires were valid, with an effective rate of 97.6%. The current smoking rate and the attempting smoking rate in Shunyi District junior high school students increased substantially, the difference was statistically significant(χ2=9.15, 11.54, P<0.01). The exposure rate of second-hand smoke among junior high school students in Shunyi District is increasing year by year. The current smoking rate and the attempting smoking rate of second-hand smoke at home and in public places were higher than those of non-exposed ones. The differences in the current smoking rates of junior high school students (χ2=25.86, 37.61, P<0.01) and the attempting smoking rate (χ2=49.51, 63-86, P<0.01) were statistically significant. The influence of Shunyi District junior high school students through different tobacco information access channels on the current smoking rate of junior high school students increased year by year. Different tobacco information access channels have significant difference in the influence of the junior middle school students’ attempting smoking rate(P<0.05). Conclusion The overall tobacco use of junior high school students in Shunyi District of Beijing is increasing by year. The exposure of second-hand smoke is not optimistic, and the supervision of tobacco information acquisition channels is urgent to be strengthened.

BACKGROUND:Bone tissue remodeling is closely related to stress loading.Currently,there are few studies or guidelines on the relationship between bone and occlusal adjustment of implant prostheses and there is also a lack of scientific evidence. OBJECTIVE:To investigate the effects of different implant occlusal gaps on stress distribution,stress peak and displacement at the implant-bone interface under Ⅰ-Ⅳ bone conditions by a finite element method. METHODS:After scanning the equal-scale tooth model with an optical scanner,equal-scale models of the upper right first molar Straumann 4.8×8 mm BL RC implant and its related components was constructed using Solidworks 2022.Then,using Mimics,Geomagic,and Solidworks software,the maxillary and mandibular bone models of class Ⅰ-Ⅳ bones were established based on the bone classification proposed by ZARB and LEKHOLM in the literature,and the NORTON and TRISI bone density classification method.The models were assembled with the occlusal gaps of 0,20,40,60,80,and 100 μm for the restorations,and an additional set of homogeneous models without density ratio settings was constructed for comparison.After the above models were imported into Hypermesh for meshing,the material assignment,boundary constraints and parameter setting were performed for the finite element analysis.Finally,250 N was used as the loading force to simulate the maxillary and mandibular stress conditions.Stress distribution,peak stress and displacement of the implant-bone interface in each group of models were analyzed and compared. RESULTS AND CONCLUSION:Under the same loading conditions,the stresses in the implant restorations were evenly distributed with the occlusal contact points.When the occlusal gap reached 80 and 100 μm,stress interruptions occurred in the implant crowns under class Ⅰ bone and class Ⅱ,Ⅲ and Ⅳ bones,respectively.The displacement of the implant-bone interface was mainly concentrated in the cortical bone region around the implant and transmitted down the long axis of the implant to the cancellous bone region at the bottom.With the changes of class Ⅰ-Ⅳ jaw bones,the displacement and Von Mises stress in the cortical bone region increased in all groups,and were greater than those in the cancellous bone region.The Von Mises stress in the cancellous bone region was similar to that in the cortical bone region except that it showed a downward trend from class Ⅱ bone.However,when the occlusal gap increased,the stress and displacement peak values in the cortical bone and the cancellous bone showed a decreasing trend.The stress of the implant-bone interface was between 20 MPa and 60 MPa when the occlusal gap was 0-40 μm for class Ⅱ-Ⅳ bones and 60 μm for class Ⅳ bone,and the stress of the other groups was less than 20 MPa.The Von Mises stress was mainly concentrated in the neck of the implant,and the peak value of von Mises stress in class Ⅱ-Ⅳ bones with the occlusal gap of 20 μm was higher than that(144.10 MPa)in class Ⅰ bone with the occlusal gap of 0 μm.In the homogeneous model with different elastic moduli,the distribution of stress and displacement was more uniform than that in the heterogeneous model and the occlusal space should increase with the decrease of jaw bone density in clinical practice.To conclude,from the perspective of biomechanics,the alveolar bone should be taken into account in the occlusal adjustment of implant denture.An occlusal gap of 20-40 μm between a single dental implant and a natural tooth in the opposite jaw is a relatively suitable solution for occlusal adjustment under different bone conditions.However,due to the particularity of finite element analysis method,it needs to be further studied in combination with clinical practice.

Objective To identify lipid metabolism genes in cerebral infarction;To explore the intervention effect of Huoxue Rongluo Prescription.Methods Multi-chip combined differential analysis(GSE61616,GSE30655)was used to identify lipid metabolism genes in cerebral infarction in combination with Reactome database,and the expression differences of lipid metabolism genes in cerebral infarction were identified and verified in GSE97537 chip;Pearson correlation analysis was used to analyze the correlation of 51 cerebral infarction samples in GSE61616,GSE30655,GSE97537,GSE137595,GSE22255,GSE163614,and GSE78731 datasets;PPI,GO and KEGG analysis of lipid metabolism genes in cerebral infarction were performed through STRING database and R clusterProfiler package.SD rats were made to the model of cerebral infarction,and was administered with Huoxue Rongluo Prescription extract 11.7 g/kg by intragastric administration for 7 days.The symptoms of neurological deficit,the changes of Nissl bodies and the mRNA expressions of PLA2G4A,SPHK1,and PTGES key genes in lipid metabolism in cerebral infarction were observed.Results TSPO,CYP1B1,PLIN2,CH25H,PLA2G4A,ANGPTL4,PTGS1,SPHK1,and PTGES were identified as lipid metabolism genes in cerebral infarction,and were significantly highly expressed and positively correlated in cerebral infarction.Among them,PTGS1,PLA2G4A,and SPHK1 interacted with each other,which were the key genes of lipid metabolism in cerebral infarction;the lipid metabolism gene in cerebral infarction mainly exerted molecular functions such as oxidoreductase activity,iron ion binding,heme binding,etc.,mediating arachidonic acid metabolism,phospholipase D signaling pathway,VEGF signaling pathway,involved in regulation of lipid metabolism process,fatty acid metabolism process,fatty acid derivative metabolism process.The symptoms of neurological deficit in the model rats with cerebral infarction were severe(P<0.001),and Huoxue Rongluo Prescription could effectively improve the neurological deficit of model rats(P<0.001).The Nissl staining indicated that the neuronal structure was abnormal and the number was significantly reduced after cerebral infarction(P<0.001).Huoxue Rongluo Prescription could increase the number of neurons(P<0.001)and repair the neuronal structure.RT-qPCR showed that the key genes of lipid metabolism in cerebral infarction were significantly higher in cerebral infarction(P<0.001),corroborated with the bioinformatics results,and Huoxue Rongluo Prescription could reduce the expression of key lipid metabolism genes of PTGS1,PLA2G4A,and SPHK1(P<0.001,P<0.01,P<0.05).Conclusion Huoxue Rongluo Prescription can down-regulate the expressions of PTGS1,PLA2G4A,SPHK1,exert molecular functions such as oxidoreductase activity,iron ion binding,heme binding,and mediate arachidonic acid metabolism,phospholipase D signaling pathway,and VEGF signaling pathway.It participates in the process of lipid metabolism regulation,fatty acid metabolism,and fatty acid derivative metabolism,increases the number of Nissl bodies,improves the symptoms of neurological deficits,and exerts neuroprotective effects.

BACKGROUND:Socket-shield technique can effectively maintain labial soft and hard tissues,but the incidence of postoperative complications such as exposure and displacement of root shield is relatively high.It is speculated that the root shield may be exposed and displaced due to excessive load after long-term function of dental implants. OBJECTIVE:Through three-dimensional finite element analysis,we aim to study the influence of varying root shield thicknesses on the stress distribution,equivalent stress peaks,and displacement in the root shield,periodontal ligaments,implant,and surrounding alveolar bone under normal occlusal loading.We also attempt to analyze the correlation between the thickness of the root shield and occurrence of mechanical events such as root shield exposure,displacement,and fracture. METHODS:Cone-beam CT data of a patient who met the indication standard of socket-shield technique for maxillary central incisor were retrieved from database.Reverse engineering techniques were used to build models of the maxillary bone and root shield,while forward engineering was used to create models for the implant components based on their parameters.Models depicting various root shield thicknesses(0.5,1.0,1.5,and 2.0 mm)were created using Solidworks 2022 software.ANSYS Workbench 2021 software was then used to simulate and analyze the effects of varying root shield thicknesses on stress distribution,equivalent stress peaks,and displacement of the root shields,periodontal ligaments,implants,and surrounding alveolar bone under normal occlusion. RESULTS AND CONCLUSION:(1)In all root shield models,the stress was concentrated on the palatal cervical side,both sides of the edges and the lower edge of the labial side.As the thickness of the root shield increased,the equivalent stress peak and displacement showed a decreasing trend.The 0.5 mm thickness model produced a stress concentration of 176.20 MPa,which exceeded the yield strength(150 MPa)of tooth tissue.(2)The periodontal ligament stress in each group was concentrated in the neck margin and upper region.With the increase of root shield thickness,the equivalent stress peak and displacement of periodontal ligament showed a decreasing trend.(3)Implant stress in all models was concentrated in the neck of the implant and the joint of the implant-repair abutment,and the labial side was more concentrated than the palatal side.With the increase of root shield thickness,the equivalent stress peak of the implant in the model showed an increasing trend.(4)In each group of models,stress of cortical bone concentrated around the neck of the implant and the periphery of the root shield,and the labial side was more concentrated than the palatal side.With the increase of the thickness of the root shield,the equivalent stress peak around the root shield decreased;the peak value of the equivalent stress of the bone around the neck of the implant showed an increasing trend.In the model,the stress of cancellous bone was mainly concentrated around the neck of the lip of the implant,the top of the thread,the root tip and the lower margin of the root shield,and the labial side was more concentrated than the palatal side.With the increase of the thickness of the root shield,the peak value of the equivalent stress of the bone around the root shield in the model showed a decreasing trend.The minimum principal stress of cortical bone in each group of models was concentrated around the neck of the implant,exhibiting a fan-shaped distribution.As the thickness of the root shield increased,the minimum principal stress of cortical bone showed an increasing trend.(5)These results indicate that different thicknesses of the root shield have different biomechanical effects.The root shield with a thickness of 0.5 mm is easy to fracture.For patients with sufficient bone width,the root shield with a thickness of 2.0 mm is an option to reduce the risk of complications such as root shield exposure,fracture,and displacement.Meanwhile,it should be taken into account to protect the periodontal ligament in the preparation process,and rounding treatments ought to be carried out on both sides and the lower edge of the root shield.

The essence-qi-spirit theory is an important part of traditional Chinese medicine， whose steady state is the material and functional basis for the balance of yin and yang in the body， making the essence， qi and spirit integrated， and body and spirit harmonized. Based on this theory， it is proposed that essence and qi depletion， spirit dissipation and qi dispersion， disharmony between yin and yang is the main pathogenesis of sleep disorders. Therefore， the method of regulating and harmonzing yin and yang by essence gathering， qi nourishing and spirit storing can be used to treat sleep disorder. The biological clock system of the circadian rhythm of sleep is regulated by the molecular oscillation that is generated by the transcription of the biological clock gene， and is a clock gradually formed by orga-nisms constantly adapting to the laws of nature. As the material basis， power， and embodiment of sound and peaceful sleep， essence， qi and spirit can perceive and transmit natural signals， whose functions are similar to what is recognized by modern science that oscillation amplifies the rhythm signal， and synchronously regulates the expression signal of the biological clock gene， thereby forming a biological clock system with “input-oscillation-output” as the feedback cycle. It is believed that the regulation method of yin and yang by essence gathering， qi nourishing and spirit storing may comprehensively regulate the physiological activities through brain/ muscle aryl hydrocarbon receptor nuclear translocator-like protein 1 （BMAL1）/circadian locomotor output cycles kaput （CLOCK）-period protein （PER）/ cryptochrome （CRY） transcriptional feedback loop， thereby adapting to the natural environment changes， playing an active role in the treatment of sleep disorders， and provideing a new idea for traditional Chinese medicine to reshape the molecular regulation system of the endogenous biological clock to prevent and treat sleep disorders.

The Chinese space station will be built around 2020. As a national space laboratory, it will offer unique opportunities for studying the physiological effects of weightlessness and the efficacy of the countermeasures against such effects. In this paper, we described the development of countermeasure systems in the Chinese space program. To emphasize the need of the Chinese space program to implement its own program for developing countermeasures, we reviewed the literature on the negative physiological effects of weightlessness, the challenges of completing missions, the development of countermeasure devices, the establishment of countermeasure programs, and the efficacy of the countermeasure techniques in American and Russian manned spaceflights. In addition, a brief overview was provided on the Chinese research and development on countermeasures to discuss the current status and goals of the development of countermeasures against physiological problems associated with weightlessness.
China ; Humans ; Program Evaluation ; Space Flight ; Weightlessness ; Weightlessness Simulation

Metabolic regulation has been proven to play a critical role in T cell antitumor immunity. However, cholesterol metabolism as a key component of this regulation remains largely unexplored. Herein, we found that the low-density lipoprotein receptor (LDLR), which has been previously identified as a transporter for cholesterol, plays a pivotal role in regulating CD8