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The global coronavirus disease 2019 (COVID-19) pandemic originating from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has exerted profound damage to millions of lives. Baicalein is a flavonoid that has gotten a lot of attention as a possible SARS-CoV-2 main protease (Mpro) inhibitor because it can fight off many different viruses. We prepared and screened three sets of databases, each containing 2563 baicalein analogues, against Mpro using molecular docking simulation. The data showed that several baicalein analogues exhibited stable binding energies relative to standard baicalein, indicating that they have some selectivity against Mpro. The binding properties of the top three stable analogues from each database were further analyzed with respect to their binding properties, such as binding mode, binding energy, and binding interaction of putative stable ligand confirmations at the target binding site region.

The pharmaceutical industry is vital for safeguarding people’s lives and health. This study is based on a macro perspective and provides a comprehensive and in-depth comparison regarding the development trends of the pharmaceutical industry in China and abroad. It is pointed out that the global market size and strategic position of the pharmaceutical industry in various countries are constantly improving. Meanwhile, the development prospects of China’s pharmaceutical industry are broad, and the potential market space is large. On this basis, we further review and explore the driving factors behind the stable and rapid development of China’s pharmaceutical industry in recent years, which include demographic changes, global economic instability, and continuous investment from innovative entities such as governments and enterprises. Moreover, from the perspective of patients, we propose the challenges faced by the pharmaceutical industry in five aspects: precision, safety, timeliness, affordability, and policy guarantee. Furthermore, targeted policy recommendations are proposed to focus on building and maintaining a refined large-scale population cohort and data platform, sorting out China’s cutting-edge technology fields, promoting the industrialization of pharmaceutical research and development, improving multi-level medical security channels, and enhance the full chain of policy protection and the implementation efficiency, thus to provide a reference for subsequent investment, policy formulation, and development decisions for China’s pharmaceutical industry.

As an important part of the bionic robotic fish, lightweight design of the frame mechanism was an effective way to improve the efficiency of bionic robotic fish propulsion. The frame and tail swing three-dimensional solid model of virtual bionic robotic fish were constructed on the three-dimensional design platform. Based on flapping wing theory, the mechanical characteristics of the tail fin of bionic robotic fish in motion were analyzed, and the instantaneous load was obtained by numerical simulation method. The caudal fin mechanism was introduced into ADAMS environment for dynamic analysis, and the motion load of the bionic robotic fish frame mechanism was obtained. Using the transient simulation of bionic robot fish frame, the real-time dynamic mechanical characteristics of bionic robotic fish were studied. Based on topology optimization, the key areas of the bionic robotic fish frame are lightweight designed. The results show that the equivalent stress, equivalent strain, total deformation and mass are reduced by 12%, 16%, 5.3% and 10.69% respectively. The lightweight design method of bionic robotic fish frame improves the maneuverability of bionic robotic fish and provides a reliable theoretical basis for the design and research of bionic robotic fish.

In order to improve the effect of precision intelligent agricultural decision support system, this paper combines big data technology to carry out precision mining of agricultural data, and combines decision tree algorithm to carry out data classification processing. Moreover, this paper obtains the most effective agricultural decision reference data through data mining, combines the agricultural decision support process to set the functional modules of the decision system, and analyzes the implementation process of each functional module. In addition, this paper studies the theoretical basis and key technologies of the agricultural production structure optimisation decision support system, and builds a precision and intelligent agricultural decision support system based on big data analysis. The system mainly performs accurate processing of agricultural data and makes effective predictions, and then makes scientific decision results. Finally, this paper verifies the structure of the model in this paper combined with experimental analysis. From the comparison of experiments, it can be seen that the precision and intelligent agricultural decision support system constructed in this paper has significant effects.

The screw drum is the direct mechanism of the shearer cutting coal and rock. The optimization design of geometric parameters and cutting strategy of screw drum has an important impact on improving coal loading performance of drum. The existing optimization design schemas of the screw drum based on the finite element method and the two-dimensional discrete element method are mostly based on a single factor or part factors. The influence of multiple design variables on the coal loading performance of the screw drum is not comprehensively considered. It is difficult to obtain the optimal solution of the geometric parameters and kinematic parameters simultaneously. In order to solve this problem, based on the test results of the physical and mechanical properties of coal, the coupling model of the shearer's screw drum cutting coal wall is established by using discrete element analysis software EDEM. The numerical simulation of coal loading performance of the shearer's screw drum is carried out. The single-factor method is used to analyze the influence of the spiral angle, diameter, hub diameter, cutting depth, drum rotation rate and traction speed of the screw drum on the coal loading performance. The three factors and three levels orthogonal test of the screw drum is designed based on the results of discrete element analysis. Through range analysis, the influence of geometric parameters of drum diameter, drum hub diameter and spiral rise angle, and kinematic parameters of cutting depth, drum rotation rate and traction speed on the coal loading performance of the screw drum is reduced in turn. According to the orthogonal test results, the optimal geometric parameters of the screw drum are 13° spiral rise angle, 1300 mm drum diameter and 475 mm drum hub diameter. The optimal cutting strategy is that the cutting depth is 600 mm, the drum rotation rate is 58 r/min, and the traction speed is 8 m/min. Under the optimal parameters, the coal loading rate of the screw drum is 76.39%, which is 15.82% higher than before.

Objective The disease burden of hypertensive cerebral hemorrhage was heavy, and the age of hypertensive cerebral hemorrhage patients was trending younger in China. This paper retrospectively analyzed the clinical data of a group of young and middle⁃aged adults with hypertensive cerebral hemorrhage, and made a detailed analysis of its clinical characteristics, so as to provide reference for the development of treatment programs. Methods A total of 120 young and middle⁃aged adults with hypertensive cerebral hemorrhage admitted in Tianjin Huanhu Hospital from January 1, 2020 to December 31, 2021 were included. According to severity of the disease, 120 patients were divided into non⁃surgery group (n=22), borehole drainage group (n=47) and endoscopic surgery group (n=51). The postoperative hematoma clearance rate, drainage tube indwelling time, length of hospital stay, Glasgow Coma Scale (GCS) score at discharge, and incidence of postoperative complications were recorded. The modified Rankin Scale (mRS) was used to evaluate the prognosis at 3 and 6 months after discharge. Results The length of hospital stay (H=3.445, P=0.000), GCS score at discharge (H=15.767, P=0.000), the incidence of postoperative bronchoppneumonitis (χ2=19.336, P=0.000) and hypoproteinemia (χ2=17.650, P=0.000), mRS scores at 3 months (H=9.651, P=0.008) and 6 months (H=8.962, P=0.011) after discharge in different groups were significant differences. Compared with the non⁃surgery group, the length of hospital stay was shorter in the endoscopic surgery group and the borehole drainage group (Z=3.816, P=0.000; Z=3.254, P=0.000), and GCS score at discharge decreased (Z=3.795, P=0.000; Z=3.104, P=0.002), postoperative bronchopneumonia (χ2=17.223, P=0.000; χ2=10.251, P=0.001) and hypoproteinemia (χ2=13.310, P=0.000) increased, and mRS score at 3 months after discharge increased (Z=2.783, P=0.009; Z=2.270, P=0.035), but the mRS score at 6 months after discharge was close to that of the non⁃surgery group (P＞0.05, for all). Compared with the two surgical methods, the hematoma clearance rate of the endoscopic surgery group was higher than that of the borehole drainage group (Z=⁃6.424, P=0.000), and the induration time of the drainage tube was shorter than that of the borehole drainage group (Z=⁃3.856, P=0.000). There were no significant differences in the length of hospital stay, GCS score at discharge, postoperative intracranial rebleeding, seizures, intracranial infection, upper gastrointestinal stress ulcer with bleeding, water and electrolyte metabolism disorders, hypoproteinemia, lower extremity deep vein thrombosis and other complications, and mRS score at 3 and 6 months after discharge (P＞0.05, for all). Conclusions Poorly controlled hypertension and bad living habits are common in young and middle⁃aged adults with intracerebral hemorrhage. Minimally invasive surgery (drilling and drainage of hematoma and endoscopic hematoma removal) is safe and reliable.

Causal discovery from observational data is a fundamental problem in many disciplines.However,existing methods such as constraint-based methods and causal function-based methods have strong assumptions on the causal mechanism of data,and are only applicable to low-dimensional data,and cannot be applied to scenarios with hidden variables.To this end,we propose a causality discovery method using information bottlenecks,called causal information bottleneck.This method divides the causal mechanism into two stages:compression and extraction.In the compression stage,we assume that there is a compressed hidden variable in the middle,while in the extraction stage,we extract the correlated information from effect variable as much as possible.Based on the causal information bottleneck,by deriving its variational upper bound,a causality discovery method based on the variational autoencoder is designed.The experimental results shows that the information bottleneck based method improves the accuracy by 10% in synthetic data and 4% in real world data.

In order to improve the working reliability of the biomimetic robotic fish, put forward a gradient reliability robust optimization design method method which is applied to the biomimetic robotic fish.Taken the bionic killer whale as the research object, based on the flapping wing motion theory, the dynamic load of the bionic killer whale was obtained by using MATLAB.Based on the theory of reliability sensitivity design, robust design theory and the theory of performance degradation, established optimization evaluation function of bionic killer whale, obtained the influence of the bionic killer whale’s design variables to reliability sensitivity gradient.The improved quantum evolutionary algorithm was used to optimize the design, the optimal solution of caudal fin propulsion mechanism was obtained.The results show that the absolute value of sensitivity of the design variables is decreased, the reliability is improved and the structure is more robust. This paper combine the flapping wing movement theory, the reliability sensitivity design theory, the reliability-based robust design theory, the theory of performance degradation and improved quantum evolutionary algorithm were combined, put forward a gradient reliability robust optimization design method method which is applied to the biomimetic robotic fish, it provides theoretical method and data support for the reliability analysis and design of bionic robot fish.

ObjectiveThe objective of the study was to investigate whether the sequence of oocyte retrieval and salpingectomy for hydrosalpinx affects pregnancy outcomes of in vitro fertilization and embryo transfer (IVF-ET) patients.Study DesignThere were 1,610 bilateral hydrosalpinx patients who underwent laparoscopy salpingectomy and IVF-ET/intracytoplasmic sperm injection (ICSI) from January 2009 to December 2018. They were divided into two groups: oocyte retrieval first group: 235 accepted oocyte retrieval before salpingectomy; operation first group: 1,375 accepted oocyte retrieval after salpingectomy. The basic information and pregnancy outcomes of the two groups were compared. The pregnancy outcomes and influencing factors were analyzed among patients at different starting times of frozen-thawed embryo transfer (FET) or oocyte retrieval after the salpingectomy.ResultsPatients in the oocyte retrieval first group had higher levels of basal follicle stimulating hormone and lower anti-Mullerian hormone levels (P 0.05). The live birth rates of patients ≥35 years old in the operation first group and the oocyte retrieval first group were not significantly different (29.3% vs. 23.3%, P = 0.240). After adjusting for age and antral follicle count (AFC), oocyte retrieval 4–6 and 7–12 months after the operation had higher accumulated pregnancy rates [OR 1.439 (1.045–1.982), P = 0.026; OR 1.509 (1.055–2.158), P = 0.024] and higher accumulated live birth rates [OR 1.419 (1.018–1.977), P = 0.039; OR 1.544 (1.068–2.230), P = 0.021]. No significant difference was observed in the pregnancy outcomes of frozen embryo transfer at different times after salpingectomy (P > 0.05).ConclusionNo contamination of the embryo or infection was observed in patients who underwent oocyte retrieval before the operation. The interval between the operation and frozen embryo transfer did not affect the pregnancy outcomes. After adjusting for age and AFC, patients who underwent oocyte retrieval 4–6 and 7–12 months after the operation had higher accumulated pregnancy rates and live birth rates.

Background Glioma is a kind of intracranial space⁃occupying lesion, which causes heavy disease burden. For glioma patients, early accurate diagnosis and early treatment could effectively prolong the progression free survival. Suspected glioma patients would be firstly examined by MRI for diagnosis. The MRI images were mainly read by radiologists artificially. The diagnosis by different radiologists might be different, and the heavy workload might cause a decline in reading efficiency. In recent years, it is becoming possible to use deep learning technology for medical image recognition and diagnosis. This study used machine learning algorithms related to artificial neural network (ANN) to assist image practitioner in reading the head MRI images of patients with glioma, which may cause labor⁃saving, and could increase the efficiency of reading images and reduce the different results cause by different personal experiencse. Methods These images were from The Cancer Imaging Archive (TCIA) database. Format of these images was DICOM. And they were from 130 adult glioma cases, a total of 40 036 copies. These images were randomly split as training set (28 025 copies) and test set (12 011 copies). Then in each set, images were split as "tumor image" and "normal image" according to medical experts' annotation. ZFNet model, a type of convolutional neural network, was used to build image recognition and classification model. The reinforcement learning curve was draw to observe the trend of accuracy of training changed with the training steps. Put the test set into the model, the overall classification accuracy of all MRI images, the positive predictive value, sensitivity, specificity and F1 ⁃ measure of the tumor images were calculated. At the same time, AlexNet was also used to build a same model to compare with the ZFNet model by the prediction indexes of the classification ability of MRI images (the prediction ability of diagnosis of glioma). Results The training accuracy of ZFNet model was 99.7% after 38 757 steps and of the AlexNet model was 98.23% after 37 984 steps. After testing, the image prediction accuracy of all MRI images of ZFNet model was 84.42% (10 140/12 011), the positive predictive value of prediction of "tumor image" was 80.77% (4817/5964), the sensitivity was 86.93% (4817/5541), the specificity was 82.27% (5323/6470), and the F1⁃measure was 83.74%. The above indexes of AlexNet model were 80.74% (9698/12 011), 77.68% (4529/5830), 81.74% (4529/5541), 79.89% (5169/6470) and 79.66%, respectively. The classification performances of ZFNet model were satisfied and were superior to AlexNet model in each dimension. Conclusions ZFNet model has a good prediction performance ability in glioma brain MRI image classification, and it is able to provide a good technical support for establishing a glioma image aided diagnosis model. doi：10.3969/j.issn.1672⁃6731.2021.03.006

As a kind of bionic robot fish,bionic killer whale played an important role in ocean development and scientific investigation. Based on the flapping wing movement theory,the bionic killer whale’s mechanism was analyzed,its instantaneous load was simulated by MATLAB. Based on the stress-strength interference theory,the bionic killer’s load reliability state function was established,the reliability index and reliability of bionic killer whale was calculated,combined with the reliability sensitivity analysis theory,the dimensionless sensitivity was obtained,analyzed the influence of the bionic killer whale’s design variables to reliability sensitivity gradient. This paper provides the theoretical basis,accurate data support and an effective numerical calculation method for the design and optimization of the bionic underwater robot with flapping wing theory as the propeller,which has important practical engineering significance.

Micromachining of various materials with femtosecond lasers operating in the GHz-burst regime has recently attracted great attention. In this contribution, we show our latest results on top-down percussion drilling in different dielectrics in this new operating regime. The dependence on the burst parameters such as burst repetition rate, number of pulses per burst, and burst energy are discussed. Moreover, we will focus on the influence of the burst shape on the drilling process. The quality of the drilled holes and their reachable dimensions are presented.

In view of problem of unsatisfactory effect of traditional training for coal mine full-hydraulic drilling rig, a training system for coal mine full-hydraulic drilling rig based on virtual reality technology was developed. The system is consisted of lower computer and upper computer, and communication between the lower computer and the upper computer is realized through FX2N series PLC programming interface. The lower computer uses PLC to collect and process control instruction of drilling rig virtual console. The upper computer applies Quest3D virtual software to realize virtual drilling rig and scene setting, key parts virtual disassembly and virtual drilling rig operation programming. The system shortens training period and reduces training cost with good human-computer interaction performance and simple operation.

In view of problems of difficulties and security risks in operation of loading and unloading of drilling pipe caused by high hole position and large hole opening angle in current coal mine tunnel drilling construction, a mine-used drilling pipe replacing device and its control system were designed. The drilling pipe replacing device is used with active drilling pipe of power head of drilling rig and the hold, to achieve loading and unloading of drilling pipe in the middle. The control system takes mine intrinsically safe and flameproof hydraulic controller as the core, and drives control proportional solenoid valve and commutation solenoid valve by PWM signal and switching signal respectively, so as to adjust the expansion and contraction speed of the cylinder. The cylinder telescopic length signal driven by proportional solenoid valve is fed back to controller by magnetostrictive sensor to form closed-loop control of the cylinder telescopic position. The test results show that the mine-used drilling pipe replacing device for drilling rig can match the existing type of drilling rig, and meet the needs of automatic loading and unloading of drilling pipe in the large-height or large-angle sidetrack drilling construction, thus improves the drilling construction efficiency and the safety of the drilling pipe replacing operation.

Paulownia Siebold et Zucc., a widely distributed native genus, has been commonly used in the furniture. The color of wood is a very important aesthetical property, and it has a fundamental influence on the commercial value of timbers. Therefore, it is critical for forest managers to select elite Paulownia clones based on the color of wood. Eighteen 5-year-old Paulownia clones grown in a hilly area in Hubei Province, China were examined in terms of color values (L*, a*, b*), color difference (ΔE*), and Hunter lab space whiteness (W) using a Chroma meter CR-400. Differences in color parameters among the 18 clones were analyzed and clustered. The results showed that the ranges of L*, a*, b*, ΔE*, and W were 77.19-80.38, 3.60-4.84, 13.79-15.69, 17.92-21.37, and 68.92-72.42, respectively. The color parameters significantly differed among the examined clones. Differential and cluster analyses indicated that clones 204, 605, 702, and 603 had higher L*, W, and lower ΔE*, rendering these as elite clones with superior color properties.

Objective To estimate the proportion of married women in China who intend to become pregnant given the country's pronatalist population policy and to investigate fecundity, with an emphasis on the influence of socioeconomic factors. Methods A nationally representative survey of 12 815 married women aged 20 to 49 years (mean: 36.8 years) was conducted during 2019 and 2020. All completed questionnaires, 10 115 gave blood samples and 11 710 underwent pelvic ultrasound examination. Fertility intention was the desire or intent to become pregnant combined with engagement in unprotected sexual intercourse. We defined infertility as the failure to achieve pregnancy after 12 months or more of unprotected intercourse. We considered an anti-Mullerian hormone level < 1.1 ng/ mL and an antral follicular count < 7 as indicating an abnormal ovarian reserve. Findings Fertility intentions were reported by 11.9% of women overall but by only 6.1% of current mothers (weighted percentages). Fertility intention was significantly less likely among women in metropolises (odds ratio, OR: 0.38; 95% confidence interval, CI: 0.31-0.45) and those with a higher educational level (OR: 0.74; 95% CI: 0.62-0.88). Overall, 18.0% had experienced infertility at any time and almost 30% had an abnormal ovarian reserve on assessment. An abnormal ovarian reserve and infertility were less likely in women in metropolises (P < 0.05) but more likely in obese women (P < 0.05). Conclusion The willingness of Chinese married women to give birth remained low, even with relaxation of the one-child policy. Abstracts in [phrase omitted], Francais, [phrase omitted] and Espanol at the end of each article. [phrase omitted] Objectif Determiner le pourcentage de femmes mariees prevoyant de tomber enceintes en Chine compte tenu de la politique demographique pronataliste du pays, et etudier la fecondite a la lumiere des facteurs socioeconomiques. Methodes Une enquete representative a l'echelle nationale portant sur 12 815 femmes mariees agees de 20 a 49 ans (moyenne: 36,8 ans) a ete organisee entre 2019 et 2020. Toutes les participantes ont rempli des questionnaires, 10 115 d'entre elles ont fourni des echantillons de sang et 11 710 ont subi une echographie pelvienne. L'intention de grossesse correspondait au desir ou a la volonte de tomber enceinte, combinee a des rapports sexuels non proteges. Nous avons defini l'infertilite comme l'incapacite a concevoir un enfant apres minimum 12 mois de rapports sexuels non proteges. Enfin, nous avons considere qu'un taux d'hormones antimullerienne < 1,1 ng/mL et un compte folliculaire antral < 7 indiquaient une reserve ovarienne anormale. Resultats Au total, 11,9% des femmes ont exprime leur desir de grossesse, mais seulement 6,1% de celles etant deja meres (pourcentages ponderes). Cette intention etait nettement moins marquee chez les femmes residant en metropole (odds ratio, OR: 0,38; intervalle de confiance de 95%, IC: 0,31-0,45) et chez celles affichant un niveau d'education plus eleve (OR: 0,74; IC de 95%: 0,62-0,88). Globalement, 18,0% ont connu l'infertilite a un moment donne et 30% presentaient une reserve ovarienne anormale lors de l'examen. Les phenomenes de reserve ovarienne anormale et d'infertilite etaient moins susceptibles de se manifester chez les femmes residant en metropole (P < 0,05) mais plus susceptibles chez les femmes obeses (P < 0,05). Conclusion En Chine, rares sont les femmes mariees a vouloir procreer, meme avec l'assouplissement de la politique de l'enfant unique. Objetivo Estimar el porcentaje de mujeres casadas en China que tienen intencion de quedarse embarazadas dada la politica demografica pronatalista del pais e investigar la fecundidad, haciendo enfasis en la influencia de los factores socioeconomicos. Metodos Durante 2019 y 2020, se realizo una encuesta representativa a nivel nacional de 12 815 mujeres casadas de entre 20 y 49 anos (media: 36,8 anos). Todas las participantes completaron cuestionarios, 10 115 aportaron muestras de sangre y 11 710 se sometieron a un examen de ultrasonido pelvico. La intencion de fertilidad fue el deseo o la intencion de quedar embarazada combinada con la participacion en relaciones sexuales sin proteccion. Se definio la infertilidad como la no consecucion de un embarazo tras 12 meses o mas de relaciones sexuales sin proteccion. Asimismo, se considero que un nivel de hormona antimulleriana Resultados El 11,9% de las mujeres informo de su intencion de fertilidad, pero solo el 6,1% de las madres actuales (porcentajes ponderados). La intencion de fertilidad era significativamente menos probable entre las mujeres de las metropolis (razon de posibilidades, OR: 0,38; intervalo de confianza del 95%, IC: 0,31-0,45) y las que tenian un nivel educativo mas alto (OR: 0,74; IC del 95%: 0,62-0,88). En general, el 18,0% habia experimentado infertilidad en algun momento y casi el 30% tenia una reserva ovarica anormal en la evaluacion. La reserva ovarica anormal y la infertilidad eran menos probables en las mujeres de las metropolis (p, Introduction Fertility rates have been on the decline globally, with recent reports predicting that 23 countries will observe the halving of their population by the end of the century. (1) [...]