Learning Agility and Adaptive Legged Locomotion via Curricular Hindsight Reinforcement Learning

Agile and adaptive maneuvers such as fall recovery, high-speed turning, and sprinting in the wild are challenging for legged systems. We propose a Curricular Hindsight Reinforcement Learning (CHRL) that learns an end-to-end tracking controller that achieves powerful agility and adaptation for the legged robot. The two key components are (I) a novel automatic curriculum strategy on task difficulty and (ii) a Hindsight Experience Replay strategy adapted to legged locomotion tasks. We demonstrated successful agile and adaptive locomotion on a real quadruped robot that performed fall recovery autonomously, coherent trotting, sustained outdoor speeds up to 3.45 m/s, and tuning speeds up to 3.2 rad/s. This system produces adaptive behaviours responding to changing situations and unexpected disturbances on natural terrains like grass and dirt

Involvement of claudin-7 in HIV infection of CD4(-) cells

BACKGROUND: Human immunodeficiency virus (HIV) infection of CD4(-) cells has been demonstrated, and this may be an important mechanism for HIV transmission. RESULTS: We demonstrated that a membrane protein, claudin-7 (CLDN-7), is involved in HIV infection of CD4(-) cells. A significant increase in HIV susceptibility (2- to 100-fold) was demonstrated when CLDN-7 was transfected into a CD4(-) cell line, 293T. In addition, antibodies against CLDN-7 significantly decreased HIV infection of CD4(-) cells. Furthermore, HIV virions expressing CLDN-7 on their envelopes had a much higher infectivity for 293T CD4(-) cells than the parental HIV with no CLDN-7. RT-PCR results demonstrated that CLDN-7 is expressed in both macrophages and stimulated peripheral blood leukocytes, suggesting that most HIV virions generated in infected individuals have CLDN-7 on their envelopes. We also found that CLDN-7 is highly expressed in urogenital and gastrointestinal tissues. CONCLUSION: Together these results suggest that CLDN-7 may play an important role in HIV infection of CD4(-) cells

Uncertainty-inspired Open Set Learning for Retinal Anomaly Identification

Failure to recognize samples from the classes unseen during training is a major limit of artificial intelligence (AI) in real-world implementation of retinal anomaly classification. To resolve this obstacle, we propose an uncertainty-inspired open-set (UIOS) model which was trained with fundus images of 9 common retinal conditions. Besides the probability of each category, UIOS also calculates an uncertainty score to express its confidence. Our UIOS model with thresholding strategy achieved an F1 score of 99.55%, 97.01% and 91.91% for the internal testing set, external testing set and non-typical testing set, respectively, compared to the F1 score of 92.20%, 80.69% and 64.74% by the standard AI model. Furthermore, UIOS correctly predicted high uncertainty scores, which prompted the need for a manual check, in the datasets of rare retinal diseases, low-quality fundus images, and non-fundus images. This work provides a robust method for real-world screening of retinal anomalies

Susceptibility of HIV-1 Subtypes B′, CRF07_BC and CRF01_AE that Are Predominantly Circulating in China to HIV-1 Entry Inhibitors

The B', CRF07_BC and CRF01_AE are the predominant HIV-1 subtypes in China. It is essential to determine their baseline susceptibility to HIV entry inhibitors before these drugs are used in China.The baseline susceptibility of 14 representative HIV-1 isolates (5 CRF07_BC, 4 CRF01_AE, and 5 B'), most of which were R5 viruses, obtained from drug-naïve patients to HIV entry inhibitors, including two fusion inhibitors (enfuvirtide and C34), two CCR5 antagonists (maraviroc and TAK779) and one CXCR4 antagonist (AMD3100), were determined by virus inhibition assay. The sequences of their env genes were amplified and analyzed. These isolates possessed similar susceptibility to C34, but they exhibited different sensitivity to enfuvirtide, maraviroc or TAK779. CRF07_BC isolates, which carried polymorphisms of A578T and V583I in the N-terminal heptad repeat and E630Q, E662A, K665S, A667K and S668N in the C-terminal heptad repeat of gp41, were about 5-fold less sensitive than B' and CRF01_AE isolates to enfuvirtide. Subtype B' isolates with a unique polymorphism site of F317W in V3 loop, were about 4- to 5-fold more sensitive than CRF07_BC and CRF01_AE isolates to maraviroc and TAK779. AMD3100 at the concentration as high as 5 µM exhibited no significant inhibitory activity against any of the isolates tested.Our results suggest that there are significant differences in baseline susceptibility to HIV entry inhibitors among the predominant HIV-1 subtypes in China and the differences may partly result from the naturally occurring polymorphisms in these subtypes. This study provides useful information for rational design of optimal therapeutic regimens for HIV-1-infected patients in China

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

КИТАЙСКАЯ ИСТОРИОГРАФИЯ О ВОПРОСАХ ПОМОЩИ СССР КИТАЮ В АНТИЯПОНСКОЙ ВОЙНЕ: СОСТОЯНИЕ ИЗУЧЕННОСТИ И ЕЁ НЕДОСТАТОЧНОСТЬ

After the outbreak of the anti-Japanese war in China, the Soviet government immediately decided to help the Chinese people. It was the largest foreign aid that the Chinese government has received since the end of German-Chinese cooperation, since the United Kingdom and the United States have not yet provided support to China. Thanks to the support of the USSR, China experienced difficult moments in the anti-Japanese war of the initial stage. For many decades, Chinese historians have been paying close attention to this period in Chinese history, as it has the most important historical value in the field of Chinese historiography, some results have been achieved, but there are also disadvantages.После вспышки антияпонской войны в Китае советское правительство сразу приняло решение оказать помощькитайскому народу. Это была самая крупная внешняя помощь, которую китайское правительство получило с момента окончания германо-китайского сотрудничества, поскольку Великобритания и США пока еще не оказывали поддержку Китаю. Благодаря поддержке СССР, Китай пережил трудные моменты в антияпонской войне начального этапа. В течение многих десятилетий китайские историки проявляют пристальное внимание к этому периоду в истории Китая, так как он имеет важнейшую историческую ценность в области китайской историографии. Некоторые результаты были достигнуты, но есть и недостатки

Microscopic detection of a red thread-like structure inside primo vessels and primo nodes from the intestine surface of rats

For many years, reports have been published describing the discovery and investigation of an additional vascular system in mammals. This primo vascular system (PVS) is distinct from the blood and lymph vascular system and consists of primo nodes (PNs) and primo vessels (PVs) as its main constituents. We investigated samples of the PVS from the intestine surface of rats and observed several instances of a red thread-like structure (RTLS) and a red oval or round structure (RORS) in PVs and PNs, respectively. We conclude that the RTLS and RORS are most likely due to erythrocytes, indicating the occurrence of extramedullary hematopoiesis inside the PVS of the intestine surface. To the best of our knowledge, this is the first report showing detailed microscopic images of an RTLS traversing four PNs and a single PV. Our report is intended to document our findings and also to motivate others to repeat and extend our study in order to investigate in detail the possible extramedullary hematopoiesis occurring inside the PVS

Risperidone induces apoptosis of human osteoblast cell line hFob1.19 through Wnt/β-catenin signaling pathway

Objective To investigate the effect of risperidone on the apoptosis of human osteoblast cell line hFob1.19 and analyze potential molecular mechanism based on Wnt/β-catenin signaling pathway. Methods hFob1.19 cells were divided into control group and risperidone intervention group (0, 5, 20, 40, 60, 80, 100 and 120 μmol/L). Cell viability was detected by CCK-8 assay. The apoptosis rate was detected by flow cytometry. RT-qPCR and Western blot was used to detect the mRNA and protein expression of BCL-2, MCL-1, BAX, and β-catenin. Results 1)Compared with the control group, the cell viability of the risperidone group decreased in a dose- and time-dependent manner (P＜0.05), while the apoptosis rate increased in a dose-dependent manner(P＜0.05). 2)Compared with the control group, the expression of pro-apoptotic gene BAX in risperidone group increased, while the expression of anti-apoptotic genes BCL-2 and MCL-1 decreased, and the expression of β-catenin decreased (P＜0.01). 3)Compared with the control group, the levels of pro-apoptotic proteins BAX and cleaved caspase-3 were increased, the levels of anti-apoptotic proteins BCL-2 and MCL-1 were decreased, and the expression of β-catenin protein was decreased in risperidone group (P＜0.01). 4) Compared with the control group, the expression of β-catenin protein in the nucleus and cytoplasm of risperidone group decreased (P＜0.05). Conclusions Risperidone induces apoptosis of hFob1.19 cells, and the mechanism may be related to the inhibition of β-catenin expression and nuclear translocation of β-catenin by risperidone, which leads to the disruption of the balance between anti-apoptotic and pro-apoptotic proteins