Compliant gait control method based on CVSLIP-FF model for biped robot walking over uneven terrain.

Bipedal walking over uneven terrain remains a challenging task due to the environmental complexity and unavoidable landing impact. To realize the stable and robust walking of biped robots, this paper proposes a compliant gait control method, which focuses on walking compliance and conducts research on two levels. In the gait generation level, a Continuous-Variable Spring-Loaded Inverted Pendulum with Finite-sized Foot (CVSLIP-FF) model is provided with the consideration of the ankle joint and compliant spring-loaded leg. Then, a CVSLIP-FF based gait generation pattern with relevant walking strategies is provided to enhance the mobility of biped robots. In the joint control level, an ankle joint admittance control strategy is applied to achieve compliant robot-environment interaction. Experimental results indicate that compared with the traditional SLIP model, the proposed method performs better adaptability to uneven terrain with a 217.77% improvement, and enables biped robots to cope with slight unknown disturbance.

Simulated microgravity altered the proliferation, apoptosis, and extracellular matrix formation of L929 fibroblasts and the transforming growth factor-ß1/Smad3 signaling pathway.

Exposure to microgravity can adversely affect the fitness of astronauts. The integrity of the skin plays a crucial role in protecting against mechanical forces and infections, fluid imbalance, and thermal dysregulation. In brief, the skin wound may cause unknown challenges to the implementation of space missions. Wound healing is a physiological process that relies on the synergistic action of inflammatory cells, extracellular matrix (ECM), and various growth factors to maintain the integrity of skin after trauma. Fibroblasts are present almost throughout the entire process of wound repair, especially in the scar formation at the endpoint of wound healing. However, there is limited knowledge about the extent to which fibroblasts are affected by the lack of gravity during wound healing. In this study, we utilized the rotary cell culture system, a ground-based facility that mimics the weightless condition, to study the alterations of L929 fibroblast cells under simulated microgravity (SMG). Our results demonstrated that the SM condition exerted negative influences on the proliferation and ECM formation of the L929 fibroblast. Whereas, the apoptosis of fibroblast was significantly upregulated upon exposure to SMG conditions. Moreover, the transforming growth factor-ß1/Smad3 (TGF-ß1/smad3) signaling pathway of L929 fibroblast related to wound repair was also altered significantly under a weightless environment. Overall, our study provided evidence that fibroblasts are strongly sensitive to SMG and elucidated the potential value of the TGF-ß1/Smad3 signaling pathway modulating wound healing in the future practice of space medicine.

Autophagy in hepatic macrophages can be regulator and potential therapeutic target of liver diseases: A review.

Hepatic macrophages are a complex population of cells that play an important role in the normal functioning of the liver and in liver diseases. Autophagy, as a maintainer of cellular homeostasis, is closely connected to many liver diseases. And its roles are not always beneficial, but manifesting as a double-edged sword. The polarization of macrophages and the activation of inflammasomes are mediated by intracellular and extracellular signals, respectively, and are important ways for macrophages to take part in a variety of liver diseases. More attention should be paid to autophagy of hepatic macrophages in liver diseases. In this review, we focus on the regulatory role of hepatic macrophages' autophagy in a variety of liver diseases; especially on the upstream regulator of polarization and inflammasomes activation of the hepatic macrophages. We believe that the autophagy of hepatic macrophages can become a potential therapeutic target for management of liver diseases.

Machine learning applied to HR-pQCT images improves fracture discrimination provided by DXA and clinical risk factors.

BACKGROUND: Traditional analysis of High Resolution peripheral Quantitative Computed Tomography (HR-pQCT) images results in a multitude of cortical and trabecular parameters which would be potentially cumbersome to interpret for clinicians compared to user-friendly tools utilising clinical parameters. A computer vision approach (by which the entire scan is 'read' by a computer algorithm) to ascertain fracture risk, would be far simpler. We therefore investigated whether a computer vision and machine learning technique could improve upon selected clinical parameters in assessing fracture risk. METHODS: Participants of the Hertfordshire Cohort Study (HCS) attended research visits at which height and weight were measured; fracture history was determined via self-report and vertebral fracture assessment. Bone microarchitecture was assessed via HR-pQCT scans of the non-dominant distal tibia (Scanco XtremeCT), and bone mineral density measurement and lateral vertebral assessment were performed using dual-energy X-ray absorptiometry (DXA) (Lunar Prodigy Advanced). Images were cropped, pre-processed and texture analysis was performed using a three-dimensional local binary pattern method. These image data, together with age, sex, height, weight, BMI, dietary calcium and femoral neck BMD, were used in a random-forest classification algorithm. Receiver operating characteristic (ROC) analysis was used to compare fracture risk identification methods. RESULTS: Overall, 180 males and 165 females were included in this study with a mean age of approximately 76 years and 97 (28 %) participants had sustained a previous fracture. Using clinical risk factors alone resulted in an area under the curve (AUC) of 0.70 (95 % CI: 0.56-0.84), which improved to 0.71 (0.57-0.85) with the addition of DXA-measured BMD. The addition of HR-pQCT image data to the machine learning classifier with clinical risk factors and DXA-measured BMD as inputs led to an improved AUC of 0.90 (0.83-0.96) with a sensitivity of 0.83 and specificity of 0.74. CONCLUSION: These results suggest that using a three-dimensional computer vision method to HR-pQCT scanning may enhance the identification of those at risk of fracture beyond that afforded by clinical risk factors and DXA-measured BMD. This approach has the potential to make the information offered by HR-pQCT more accessible (and therefore) applicable to healthcare professionals in the clinic if the technology becomes more widely available.

Proteomic analysis of the effects of simulated microgravity in human gastric mucosal cells.

Microgravity is an ecological factor that affects the environment of the body. In this study, quantitative isobaric labeling (tandem mass tag) method was used to study the changes in human gastric mucosal cells under simulated microgravity for the first time. Comparative proteomic analysis identified 394 (202 upregulated and 192 downregulated) and 542 (286 upregulated and 256 downregulated) proteins differentially regulated by simulated microgravity after 3 and 7 days, respectively. Then the identified proteins were subjected to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses for further exploration. The results of the analysis showed that the ribosomes of gastric mucosal cells were significantly impacted after exposure to simulated microgravity for 3 days, and the cells appeared to be in a state of stress and inflammation. Exposure to simulated microgravity for 7 days significantly affected the mitochondria of the cells, oxidative stress became more evident, while inflammation and weakened connections were observed in the cells. The results of this study highlighted the temporal response trend of gastric mucosal cells to the stressor of microgravity at the two time points of 3 and 7 days. These findings will provide insights into the development of methods to protect the gastric mucosa during space flight.

Inflammation is involved in response of gastric mucosal epithelial cells under simulated microgravity by integrated transcriptomic analysis.

Astronauts suffer from inflammatory changes induced by microgravity during space flight. Microgravity can significantly affect the inflammatory response of various cell types and multiple systems of the human body, such as cardiovascular system, skeletal muscle system, and digestive system. The aim of this research was to identify the key genes and pathways of gastric mucosa affected by microgravity. Human gastric mucosal epithelial GES-1 cells were cultured in a rotary cell culture system (RCCS) bioreactor to simulate microgravity. The gene expression profiles of GES-1 cells were obtained using Illumina sequencing platform and differentially expressed genes were identified by DESeq2 software, then Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed. Subsequently, a protein-protein interaction (PPI) network was constructed. Compared with a normal gravity (NG) group, a total of 943 DEGs, including 192 downregulated genes and 751 upregulated genes, were identified. These DEGs were associated with findings that included response to interleukin-1, positive regulation of inflammatory response, and positive regulation of neuroinflammatory response. Furthermore, these DEGs were mainly enriched in herpes simplex virus 1 infection, cytokine-cytokine receptor interaction, and NOD-like receptor signaling pathway. Thus, 21 hub genes were identified from PPI network, including IL6, IL1B, ITGAM, CXCL8, ITGAX, CCL5, SERPINA1, APOE, CSF1R, VWF, GBP1, APOB, CYBB, HLA-DRB1, CD68, FGG, FGA, OASL, NOD2, OAS2 and FCGR2A. These findings suggested that simulated microgravity upregulated inflammation-related genes and pathways of GES-1 cells, which may play important roles in the response to microgravity and provide useful information for preventing mucosal damage in astronauts. In conclusion, this study revealed the key genes and pathways associated with simulated microgravity and indicated that simulated microgravity induced an inflammatory response in gastric mucosal epithelial cells.

Autophagy in Gastric Mucosa: The Dual Role and Potential Therapeutic Target.

The incidence of stomach diseases is very high, which has a significant impact on human health. Damaged gastric mucosa is more vulnerable to injury, leading to bleeding and perforation, which eventually aggravates the primary disease. Therefore, the protection of gastric mucosa is crucial. However, existing drugs that protect gastric mucosa can cause nonnegligible side effects, such as hepatic inflammation, nephritis, hypoacidity, impotence, osteoporotic bone fracture, and hypergastrinemia. Autophagy, as a major intracellular lysosome-dependent degradation process, plays a key role in maintaining intracellular homeostasis and resisting environmental pressure, which may be a potential therapeutic target for protecting gastric mucosa. Recent studies have demonstrated that autophagy played a dual role when gastric mucosa exposed to biological and chemical factors. More indepth studies are needed on the protective effect of autophagy in gastric mucosa. In this review, we focus on the mechanisms and the dual role of various biological and chemical factors regulating autophagy, such as Helicobacter pylori, virus, and nonsteroidal anti-inflammatory drugs. And we summarize the pathophysiological properties and pharmacological strategies for the protection of gastric mucosa through autophagy.

O-arm navigation for sacroiliac screw placement in the treatment for posterior pelvic ring injury.

PURPOSE: This study aims to investigate the application value of O-arm navigation system in sacroiliac screw placement for the treatment of unstable pelvic ring injury. METHODS: A total of 40 patients (mean age = 30.75 ± 14.99 years, 25 males, 15 females) were included. From January 2016 to July 2018, 40 patients with posterior pelvic ring injury treated in our hospital were included. Of them, 19 patients underwent O-arm navigation for screw placement (O-arm group) while the other 21 received C-arm fluoroscopy guidance (C-arm group) for sacroiliac screw placement. Intraoperative outcomes and the outcome of screw placement were compared between groups. The quality of radiological images was assessed by Matta's radiological outcome grade. The outcome of complex pelvic fracture treatment was evaluated by Majeed Functional score. RESULTS: All demographic and clinical characteristics were comparable between the two groups. Compared with the C-arm groups, the O-arm group had a shorter surgery time (33.19 ± 3.14 vs. 48.35 ± 4.38 min, P < 0.001), a higher overall good outcome "excellent + good" rate of screw placement (95.45% vs. 73.91%, P < 0.05), and a significantly higher Majeed Functional score better outcome of complex pelvic fracture treatment at 1 and 3 months postoperation (both P < 0.05). CONCLUSION: Our results demonstrated that O-arm navigation system is feasible and safe for the treatment of posterior pelvic ring injury and can effectively improve the accuracy and safety of sacroiliac screw placement, shorten the operation time, and help rapid postoperative functional recovery.

The effects of microgravity on the digestive system and the new insights it brings to the life sciences.

BACKGROUND: Weightlessness is a component of the complex space environment. It exerts adverse effects on the human body, and may pose unknown challenges to the implementation of space missions. The regular function of the digestive system is an important checkpoint for astronauts to conduct missions. Simulated microgravity can recreate the changes experienced by the human body in a weightless environment in space to a certain extent, providing technical support for the exploration of its mechanism and a practical method for other scientific research. METHODS AND MATERIALS: In the present study, we reviewed and discussed the latest research on the effects of weightlessness or simulated microgravity on the digestive system, as well as the current challenges and future expectations for progress in medical science and further space exploration. RESULTS: A series of studies have investigated the effects of weightlessness on the human digestive system. On one hand, weightlessness and the changing space environment may exert certain adverse effects on the human body. Studies based on cells or animals have demonstrated the complex effects on the human digestive system in response to weightlessness. On the other hand, a microgravity environment also facilitates the ideation of novel concepts for research in the domain of life science. CONCLUSION: The effects of weightlessness on the digestive system are considerably complicated. The emergence of methods that help simulate a weightless environment provides a more convenient alternative for assessing the impact and the mechanism underlying the effect of weightlessness on the human body. In addition, the simulated microgravity environment facilitates the ideation of novel concepts for application in regenerative medicine and other fields of life science.

[Analysis of the volatile components in Minnan oolong tea by headspace solid phase microextraction coupled with comprehensive two-dimensional gas chromatography-time of flight mass spectrometry and the application in its variety identification].

A method to analyze the volatile components in Minnan oolong tea was developed based on headspace solid phase microextraction (HS-SPME) coupled with comprehensive two-dimensional gas chromatography-time of flight mass spectrometry (GC×GC-TOF MS). Volatile compounds of 48 oolong tea samples with different qualities and production seasons from five varieties (Tieguanyin, Huangjingui, Benshan, Maoxie and Meizhan) were extracted by HS-SPME and analyzed by GC×GC-TOF MS. More than 2 000 peaks were obtained from each sample, and 51 common compounds were tentatively identified by comparison with the standard mass spectrum databases, retention indices and structure spectra. The projection score of the common compounds obtained from principal component analysis ( PCA) had presented a straightforward classification trend for different oolong tea varieties. In addition, 9 compounds which had significant impact on the classification were selected by stepwise discriminate analysis, and used as variables to establish four discriminated functions by Fisher's discriminate analysis (FDA). The accuracy for the recognition of 48 samples was 97. 9%. The results had demonstrated the feasibility of the method to be used to discriminate the oolong tea varieties.

[Determination of ten pesticides of pyrazoles and pyrroles in tea by accelerated solvent extraction coupled with gas chromatography-tandem mass spectrometry].

An effective method was developed and applied to determine the residues of ten pesticides of pyrazoles and pyrroles in tea by accelerated solvent extraction coupled with gas chromatography-tandem mass spectrometry (ASE-GC-MS/MS). The samples were extracted with ethyl acetate-hexane (1:1, v/v) for 5 min at 1.03 x 10(7) Pa and 100 degree C for one cycle. Then, they were purified by Envi-Carb/PSA column, and eluted by ethyl acetate-hexane (1:1, v/v). The analytes were determined by GC-MS/MS and quantified by external standard method. The limits of quantification were 0.003 mg/kg for fenpyroximate, 0.001 mg/kg for fipronil-sulfide, 0.002 mg/kg for fipronil, 0.005 mg/kg for fipronil-sulfone, 0.002 mg/kg for chlorfenapyr, 0.006 mg/kg for flusilazole, 0.001 mg/kg for difenzoquat, 0.001 mg/kg for pyraflufen-ethyl, 0.000 3 mg/kg for tebufenpyrad and 0.005 mg/kg for tolfenpyrad. The results show that the proposed method is sensitive and accurate for the determination of the ten pesticide residues.

[Multi-residue determination of 289 pesticides in garlic by gas chromatography and gas chromatography/mass spectrometry].

A new idea of solvent transfer technique was developed and applied to determine 283 pesticide residues in garlic by gas chromatography-mass spectrometry (GC-MS) (method I), and the other method using normal phase silica/selective elution technique was applied to determine 6 pesticide residues with strongly polar in garlic by gas chromatography (method II). For the method I, the residues were extracted from homogenized tissue with acetonitrile-water, separated with liquid-liquid partition; the clear supernatant was purified by solvent transfer technique and solid phase extraction (Envi-18 and LC-NH2 columns), then was analyzed by GC-MS. For the method II, the residues were extracted from homogenized tissue using ethyl acetate and sodium sulfate assisted by ultrasonication. The supernatant was purified by solid phase extraction (primary secondary amine (PSA) powder and LC-Si column) prior to GC analysis. The determination was performed by using selected ion monitoring (SIM) mode in GC-MS method and flame photometric detector (FPD) in GC method, then external standard method was used in the quantification. Under the optimal conditions, the detection limits for the two methods (S/N > or = 10) of pesticides were 0.01-0.05 mg/kg, the recoveries carried out by the addition of standards of 0.01-0.20 mg/kg were 52%-163%, among which the recoveries for 88% pesticides were between 70% and 120%; the recoveries of the method II were 70%-111%; while the relative standard deviations were 2.4%-18% and 3.2%-9.3%, respectively. The model of solvent transfer technique and the sensitivity improvement of GC-MS was also studied. The methods are easy, fast, more sensitive, and can meet the requirement of the multiresidual analysis in garlic.

[Determination of avermectin residues in tea by ultra-performance liquid chromatography-electrospray tandem mass spectrometry].

A simple and rapid analytical method for the simultaneous determination of abamectin, emamectin, eprinomectin, ivermectin, doramectin and moxidectin residues in tea by ultra-performance liquid chromatography-electrospray tandem mass spectrometry (UPLC/ESI-MS/MS) has been developed. The avermectins were extracted from the tea with acetonitrile after the tea was infiltrated in saturated aqueous NaCl solution, then cleaned up with a C18 solid phase extraction cartridge. The linear ranges were 2.0-50 microg/L and the correlation coefficients were all above 0.9920. Several UPLC-MS/MS conditions that included the mobile phase, monitor ions and the selection of calibration of the measurement were studied. The average recoveries and the relative standard deviations ranged from 61.7% to 85.4% and from 9.37% to 17.19%, respectively, in spiked samples at the concentrations of 5, 10, 20 microg/kg for moxidectin and 2, 5, 10 microg/kg for other analytes. This method is suitable for the determination of avermeetin residues in tea.

[Determination of quinoxyfen residue in foodstuffs of plant and animal origins by high performance liquid chromatography].

A high performance liquid chromatographic (HPLC) method has been developed for the determination of quinoxyfen residue in various food matrixes including soybean, cauliflower, cherry, mushroom, wine, tea, honey, pork liver, chicken and eel. The analyte was extracted by ethyl acetate, and then purified with aminopropyl solid phase extraction (NH2 SPE) cartridge. Post-extraction gel permeation chromatography (GPC) was used for animal (except honey) and fishery products prior to NH2 SPE cleanup. The average recoveries and relative standard deviations (RSDs) for the analysis of all samples fortified in the range of 0.010 - 5.0 mg/kg were in the ranges of 82% - 96% and 3.2% - 11.8%, respectively. Good linearity was obtained in the concentration range from 0.050 to 50.0 mg/L. The limit of detection was 0.010 mg/kg. The proposed method was successfully applied to the analysis of quinoxyfen residue in various food samples.

[Determination of endosulfan pesticide residues in Litopenaeus vannamai by capillary gas chromatography].

A method is described for the determination of endosulfan pesticide residues in Litopenaeus vannamai by capillary gas chromatography. The residues of alpha-endosulfan and beta-endosulfan were extracted from the sample with ethyl acetate, and the extract was cleaned up using a neutral alumina column and an active carbon column after concentrated and then eluted with a mixture of n-hexane-ethyl acetate (1 : 1, v/v). During the process of purification, the flow rate of eluent was controlled within 3 mL/min. The eluate was collected and evaporated to 1 mL for analysis. The determination was performed on a gas chromatograph equipped with an electron capture detector. The retention time was used for qualification and the external calibration standard was used for quantitation. The results obtained showed that the recoveries were 80.5% - 97.3% for alpha-endosulfan and 81.1% - 109.5% for beta-endosulfan. The limit of detection (LOD) was 0. 002 mg/kg, and the limit of quantitation (LOQ) was 0. 007 mg/kg for both. The precision of the method, expressed as the relative standard deviation for the within-laboratory repeatability, was generally below 8.5%. The method was used for the analysis of Litopenaeus vannamai samples from Guangxi Province, a Litopenaeus vannamai aquiculture area in south China.