Mechanisms of recognition of the outlines of “vanishing” optotypes

The aim of the present work was to study the interaction between the optical properties of images of “ disappearing” optotypes and their recognition thresholds. The “disappearing” optotypes were figures with complex outlines and had a unique property-they were close to the threshold of recognition and observation, which increases the accuracy of measurement of visual acuity and the subjects’ attention to them. The recognition distances of “disappearing” optotypes were measured. A relationship was found between the recognition distance of “disappearing” optotypes and different optical density profiles on the one hand and the spatial and spatial frequency characteristics of the stimuli on the other. The decisive factor determining the threshold of recognition of optotypes in spatial frequency terms is its spatial frequency spectrum; that in spatial terms is the width of the black/white pair or black-white triad in the complex outline. Regardless of the shape of the optotype, one of the most important limiting factors was the concordance of this test with the scattering function of the subject’s eye optics. __________ Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 91, No. 9, pp. 1080–1090, September, 2005.     

Studies of the Mechanism of Development of “Deprivation” Potentiation of Population Responses of Neurons in Field CA1 of Living Hippocampal Slices

Experiments on rat hippocampal slices were performed with testing of the synaptic connections of Schaffer collaterals and neurons in field CA1 to study the effects of interrupting low-frequency test stimulation (0.05 Hz) on the amplitude of population spikes. These studies demonstrated a correlation between the duration of pauses in stimulation (form 10 to 120 min) and increases in the amplitude of spikes (on average by 30–100% of baseline response magnitude). This deprivation potentiation was additive and could persist for long periods of time (testing was up to 1 h). Preliminary induction of long-term post-tetanic potentiation, which prevented the subsequent development of the late, but not the short-term phase, for 1–3 h, led to suppression of the development of deprivation potentiation after a 60-min pause in stimulation. Similar results were obtained in experiments using 20 M polymyxin B, which blocks protein kinase C and the PKC-dependent phase of long-term post-tetanic potentiation; this is evidence supporting the previously advanced hypothesis that the development of deprivation potentiation and the late, PKC-dependent phase of long-term post-tetanic potentiation share common mechanisms, associated with people phosphorylation.     

Effect of Cell–Cell Interactions on the Observable Strength of Adhesion of Sheets of Cells

Previous research in cellular adhesion has focused primarily on studying isolated cells under conditions where cells do not interact with each other. However, in vivo cells form sheets where both cell–substratum and cell–cell interactions contribute to the overall adhesive behavior. Our understanding of how cell–cell and cell–substratum interactions affect the overall process of cell adhesion in these situations is limited. To address this problem, we developed a systematic approach to evaluate how cell–cell and cell–substratum interactions affect the critical shear stress for detachment for semiconfluent and confluent sheets of cells. Our studies were based on subjecting cultures of adherent cells to a defined hydrodynamic flow in a radial-flow chamber with a gap height of 140 m. Using phase-contrast microscope imaging and analysis we measured shear-dependent patterns of detachment as a function of the extent of cell confluency. Our results show that the critical shear stress for detachment is maximum at intermediate extents of confluency of 10%–40%. These results have important implications for sodding vascular grafts and tissue engineering. © 1999 Biomedical Engineering Society. PAC99: 8718-h, 8719Rr     

Analysis of influencing factors of fear of falling in patients with knee osteoarthritis and construction of nomogram model北大核心

BACKGROUND: Fear of falling will aggravate the instability of the knee joint in patients with knee osteoarthritis, leading to the reduction of activities and the decline of the overall body function. Therefore, screening the factors affecting the fear of falling in patients with knee osteoarthritis and constructing a nomogram model can reduce the injury caused by the fear of falling and provide a reference for the formulation of individualized diagnosis and treatment plans. OBJECTIVE: To explore the influencing factors and conditions of fear of falling in patients with knee osteoarthritis, and to establish a predictive model for the risk of fear of falling in patients with knee osteoarthritis. METHODS: A cross-sectional study method was used to enroll 560 patients with knee osteoarthritis who visited Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine from September 2019 to February 2021. Among them, 469 were in the falling fear group and 91 were in the non-falling fear group. The general information of patients, the Western Ontario and McMaster Universities Arthritis Index, and the Hospital Anxiety and Depression Scale scores were analyzed and compared between the two groups to determine the influencing factors of the fear of falling in knee osteoarthritis patients. Receiver operating characteristic curves of the influencing factors were drawn to obtain the Youden’s index with diagnostic value for the fear of falling. The maximum value of the Youden index of each factor was the best diagnostic value (cutoff value) of the knee osteoarthritis fear of falling. A nomogram was drawn to establish the knee predictive model for the fear of falling in patients with knee osteoarthritis. RESULTS AND CONCLUSION: (1) Logistic regression analysis showed that height and male were the protective factors for the fear of falling in patients with knee osteoarthritis, and age, unemployment, Western Ontario and McMaster Universities Arthritis Index stiffness scale score, and anxiety scale score were the risk factors for the fear of falling in patients with knee osteoarthritis. (2) Receiver operating characteristic curve results showed that Western Ontario and McMaster Universities Arthritis Index had a significant diagnostic value for knee osteoarthritis patients (Youden’s index=0.733), followed by age, anxiety, and gender. (3) The results of the nomogram showed that the maximum score of the Western Ontario and McMaster Universities Arthritis Index stiffness scale (8 points) could account for 41.6% of the predictors of knee osteoarthritis fear of falling. (4) It is concluded that there is a high incidence of fear of falling among patients with knee osteoarthritis, and joint stiffness and female gender may be risk factors for fear of falling, while low height may be a protective factor for fear of falling, and there is a need to focus on fear of falling and the management of related factors in clinical treatment interventions. © 2023, Publishing House of Chinese Journal of Tissue Engineering Research. All rights reserved.     

Numerical Simulation of thePorous Structure of Biomaterials

Porous biomaterials are widely used as bone replacement materials because of thers high biocompatibility and osteoconductivity property. Understanding of their porous structure (i. e. geometrical and topological characteristic) and studying how to the body fluid flow through them are essential to investigate thed egradation behaviour at the surface-liquid interface. This research develops a numerical model to simulate the porous structure of biomaterials based on the stochastic approach in pore size distribution and interconnectivity.     

Investigation of the “valency” of antibodies by means of azoproteins

Summary The valency of antibodies was studied by the method of exhaustion of antisera against mono-and diazoproteins, and subsequent cross reactions both with the antibodies left over in the supernatant fluid of the serum and with the precipitating and nonprecipitating antibodies isolated from the precipitate.It was proved that the antibodies interact with the antigens as multivalent compounds.The valency determined with regard to the azoproteins is dependent upon the number of groups introduced.Thus, bivalent antibodies correspond to monoazoproteins and trivalent ones to diazoproteins.The valency of antibodies is, evidently, determined by the structural similarity of the heterologous and the immunizing antigens as well as by the less complete specific conformity between the individual structural peculiarities of the antigen and its antibody.From the Tashkent Pharmaceutical Institute (Director-Docent M. A. Azizov)Presented by Active Member AMN SSSR N. N. Zhukov-Verezhnikov     

The Quantitative Stereologic Analysis of the Ultrastructure of Scirrhous Carcinoma of Breast

1.IntroductionInordertofindQutthebestwaytodiagnoseandtreatthecarcinomaofbreaSt,thestudyforpathology,andmorphometryorstereologyareverynecessary.ButthequantitativeanalysisoftheultrastructllreortheStere0l0gyaboutbreaStcarcinomahasnotyotbeenseenandnottobereported('x'x').Sowemeasured28morphologicalparametersofmit0chondrion,lysosome,roughendoplasmicreticulumandribosomeintencasesofscirrhouscarcinomaofbreastbystereologicmethods.Wehopedthatthisworkwouldpr0vides0mequantitativedaaforpathologyandearlydi…     

A case of prevailing deficit of nonliving categories or a case of prevailing sparing of living categories?

We describe a new case of semantic deficit in which nonliving categories are disproportionately impaired. PL, a woman affected by progressive degeneration of the left temporal lobe, was examined twice, at a distance of 1 year. The deficit was first apparent on naming and on a verbal semantic questionnaire, but a year later nonliving categories were disproportionately affected also on verbal comprehension (word/picture matching task). Body parts and musical instruments were also investigated: the former was the best preserved category, whereas the latter was the most severely affected. Considering all categories, functional and perceptual information was not differently affected, but there was a trend toward a worse score for nonliving category functional questions. Discussing the current hypotheses on the genesis of category dissociations, we conclude that nonliving categories might not be a true domain, and that their impairment could simply derive from the relative sparing of the domains of the living categories, for which separate cognitive and anatomical representations can be better postulated. Finally, we discuss the problems raised by published cases in an attempt to find a consistent anatomical substrate for category dissociations.     

Effects of Terahertz Radiation at Atmospheric Oxygen Frequency of 129?GHz on Blood Nitrite Concentrations under Conditions of Different Types of Stress against the Background of Administration of Nonselective Inhibitor of Constitutive NO-Synthases

We studied the effect of terahertz radiation at atmospheric oxygen frequency 129 GHz on blood nitrite concentration in different types of experimental stress against the background of administration of nonselective inhibitor of constitutive NO-synthases. Normalizing effects of radiation on blood nitrite dynamics in animals with acute stress was shown after 15-min exposure and in animals with chronic stress after 30-min exposure. No positive effect of terahertz radiation was observed on altered blood nitrite concentration in male rats after preliminary administration of nonselective constitutive NO-synthase isoform inhibitor L-NAME.     

Construction of a risk model of steroid-induced necrosis of the femoral head and prediction of potential Chinese medicine treatments北大核心

背景:随着疾病治疗模式的改变,人们已经意识到中医药在激素性股骨头坏死治疗过程中的重要性,因此利用生物信息学从分子水平分析激素性股骨头坏死的发病机制,构建疾病风险模型,并预测具有潜在治疗作用的中药,为后期中医药治疗激素性股骨头坏死提供一定的理论依据。目的:基于生物信息学挖掘激素性股骨头坏死的竞争性内源RNA(ceRNA)调控网络,分析其在激素性股骨头坏死中的分子调控机制,预测相关疾病靶点并构建疾病风险模型,同时预测具有潜在治疗作用的中药。方法:检索GEO数据库,下载激素性股骨头坏死的矩阵文件GSE123568和基因注释文件GPL15207。借助R语言等软件分析得到差异表达的长链非编码RNA与mRNA,并通过公共数据库预测与差异表达长链非编码RNA关联的miRNA-mRNA,再将预测到的mRNA与差异表达mRNA取交集,整合得到ceRNA网络。随后采用STRING数据库和Cytoscape软件筛选关键基因,利用R语言分析关键基因的功能与相关通路,并挖掘关键ceRNA网络。最后根据关键基因构建激素性股骨头坏死的风险模型,并进行中药预测。结果与结论:(1)与健康对照相比,激素性股骨头坏死患者共有7个长链非编码RNA和1763个mRNAs存在差异表达;(2)筛选出STAT3、KAT2B、AGO4、JAK2、JAK1、PTGS2共6个关键基因;(3)关键基因所富集的功能包括对肽激素的反应、白细胞介素6介导的信号通路、细胞对白细胞介素6的反应等生物学过程,涉及JAK-STAT、脂肪细胞因子、催乳素等信号通路;(4)4种mi RNAs(mi R-135a-5p、mi R-137、mi R-17-5p、miR-20b-5p)和2种长链非编码RNA(SNHG11、C20orf197)可能在导致激素性股骨头坏死发生发展过程中发挥关键作用;(5)KAT2B最有可能是激素性股骨头坏死发生发展的风险因子;(6)郁金、淫羊藿、黄芪具备治疗激素性股骨头坏死疾病靶点的可能。通过对激素性股骨头坏死相关长链非编码RNA介导的ceRNA网络进行分析,识别出潜在的疾病靶点、信号通路及潜在治疗中药,为进一步阐明其发病机制,并为后续的实验研究提供参考依据。     

Universalization of health or of social security?

This article presents an analysis of the architecture of Mexico's health system based on the main economic problem, failing to achieve a GDP growth rate to increase real wages and give workers in formal employment coverage social security. This analysis describes the relationship between social security of the population and employment status of it (either formal or informal employment) and the impact that this situation poses to our health system. Also, it ends with a reform proposal that will give all workers the same social rights, ie to grant universal social security.     

Biological Activity of Some Derivatives of β-Cyclodextrin

New compounds of β-cyclodextrin containing covalently bound (conjugated) residues of acetylsalicylic and 1-(4-isobutylphenyl)-propionic acids were synthesized in the reaction of chlorides of the corresponding acids with β-cyclodextrin. We studied antiplatelet and antiphlogistic properties of these substances. It was shown that new compounds are comparable and in some cases are superior to the reference drugs acetylsalicylic acid and ibuprofen by anti-inflammatory and antiaggregant activities.     

Effect of enamel-grinding on adhesionstrength of enamel-resin junction

INTRODUCTION　　 In the treatmentof labial teeth by light-cure composite resin,before acid-etchingthe artificial grinding method isusually adopted to thin the enamel supperficial layerso as to enhance the acid-etching effect and to improve the fixation of…