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Quadruped bionic robots are favored by development experts because of their broad application prospects, such as interstellar exploration, educational companionship, and social inspections. Quadruped robots were developed and inspired by mammals, which are known to exist in most areas on the earth's land surface. However, quadruped robots cannot achieve such an ideal state due to various reasons. At present, the adaptive problem of quadruped robots under a complex and changeable terrain has made significant progress, as reported in related literature. However, the case of robots that are as flexible as mammals in nature and meet the needs of multi-functional and multi-scenarios are still poorly understood. A quadruped robot is prone to posture instability when dynamically traveling in a ground environment with variable rigidity. This work proposes a real-time adjustment strategy of the active variable stiffness of the legs. This strategy estimates the landing in real time based on the motion state of the fuselage and legs after the robot touches the ground. The coupling stiffness of the legs and the ground and the difference between the coupling stiffness of the front and rear legs and the ground is compensated to the corresponding landing legs. This enables the robot to quickly adapt to the ground with different stiffness characteristics after landing, especially when the ground stiffness differs greatly. The Simulink-SimMechanics simulation platform is established with the diagonal legs on the same stiffness ground and on different ground environments with variable stiffness. The active leg stiffness adjustment strategy combined with conventional attitude feedback control is tested, and results are compared with those using only a conventional attitude feedback control. Results show that through the active variable stiffness of the legs, the quadruped robot realizes the compensation and correction of the pitch and roll angle of the fuselage during the transition between soft and hard ground. Moreover, the control effect is better than that of the conventional attitude feedback control alone.

Gas emitted from landfills contains a large quantity of volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs), some of which are carcinogenic, teratogenic, and mutagenic, thereby posing a serious threat to the health of landfill workers and nearby residents. However, the global hazards of VOCs and SVOCs in landfill gas to human health remain unclear. To quantify the global risk distributions of these pollutants, we collected the composition and concentration data of VOCs and SVOCs from 72 landfills in 20 countries from the core database of Web of Science and assessed their human health risks as well as analyzed their influencing factors. Organic compounds in landfill gas were found to primarily result from the biodegradation of natural organic waste or the emissions and volatilization of chemical products, with the concentration range of 1 × 10-1–1 × 106 μg/m3. The respiratory system, in particular, lung was the major target organ of VOCs and SVOCs, with additional adverse health impacts ranging from headache and allergies to lung cancer. Aromatic and halogenated compounds were the primary sources of health risk, while ethyl acetate and acetone from the biodegradation of natural organic waste also exceeded the acceptable levels for human health. Overall, VOCs and SVOCs affected residents within 1,000 m of landfills. Air temperature, relative humidity, air pressure, wind direction, and wind speed were the major factors that influenced the health risks of VOCs and SVOCs. Currently, landfill risk assessments of VOCs and SVOCs are primarily based on respiratory inhalation, with health risks due to other exposure routes remaining poorly elucidated. In addition, potential health risks due to the transport and transformation of landfill gas emitted into the atmosphere should be further studied.

BackgroundPerforming biopsy for intermediate lesions with PI-RADS 3 has always been controversial. Moreover, it is difficult to differentiate prostate cancer (PCa) and benign prostatic hyperplasia (BPH) nodules in PI-RADS 3 lesions by conventional scans, especially for transition zone (TZ) lesions. The purpose of this study is sub-differentiation of transition zone (TZ) PI-RADS 3 lesions using intravoxel incoherent motion (IVIM), stretched exponential model, and diffusion kurtosis imaging (DKI) to aid the biopsy decision process.MethodsA total of 198 TZ PI-RADS 3 lesions were included. 149 lesions were BPH, while 49 lesions were PCa, including 37 non-clinical significant PCa (non-csPCa) lesions and 12 clinical significant PCa (csPCa) lesions. Binary logistic regression analysis was used to examine which parameters could predict PCa in TZ PI-RADS 3 lesions. The ROC curve was used to test diagnostic efficiency in distinguishing PCa from TZ PI-RADS 3 lesions, while one-way ANOVA analysis was used to examine which parameters were statistically significant among BPH, non-csPCa and csPCa.ResultsThe logistic model was statistically significant (χ2 = 181.410, p

Purpose: To evaluate the diagnostic performance of PI-RADS v2, proposed adjustments to PI-RADS v2 (PA PI-RADS v2) and biparametric magnetic resonance imaging (MRI) for prostate cancer detection. Methods: A retrospective cohort of 224 patients with suspected prostate cancer was included from January 2016 to November 2018. All the patients underwent a multi-parametric MR scan before biopsy. Two radiologists independently evaluated the MR examinations using PI-RADS v2, PA PI-RADS v2, and a biparametric MRI protocol, respectively. Receiver operating characteristic (ROC) curves for the three different protocols were drawn. Results: In total, 90 out of 224 cases (40.18%) were pathologically diagnosed as prostate cancer. The area under the ROC curves (AUC) for diagnosing prostate cancers by biparametric MRI, PI-RADS v2, and PA PI-RADS v2 were 0.938, 0.935, and 0.934, respectively. For cancers in the peripheral zone (PZ), the diagnostic sensitivity was 97.1% for PI-RADS v2/PA PI-RADS v2 and 96.2% for biparametric MRI. Moreover, the specificity was 84.0% for biparametric MRI and 58.0% for PI-RADS v2/PA PI-RADS v2. For cancers in the transition zone (TZ), the diagnostic sensitivity was 93.4% for PA PI-RADS v2 and 88.2% for biparametric MRI/PI-RADS v2. Furthermore, the specificity was 95.4% for biparametric MRI/PI-RADS v2 and 78.0% for PA PI-RADS v2. Conclusions: The overall diagnostic performance of the three protocols showed minimal differences. For lesions assessed as being category 3 using the biparametric MRI protocol, PI-RADS v2, or PA PI-RADS v2, it was thought prostate cancer detection could be improved. Attention should be paid to false positive results when PI-RADS v2 or PA PI-RADS v2 are used.

Abstract Background To report refractive outcomes, describe types of strabismus and evaluate the outcomes of surgical intervention for unilateral coronal synostosis (UCS) in paediatric patients. Methods This study retrospectively included 30 UCS cases. Patients aged from 3 months to 6 years (median: 1.8 years) were enrolled from January 2018 to December 2019 at Shanghai Children’s Hospital. Sixteen patients had all types of strabismus; 15 of these patients underwent surgery. Results Refractive errors of 30 cases were included. In 60% of patients, astigmatism of 1.00D or more existed in not less than one eye at last record. Twenty (66.7%) patients had the larger amount of astigmatism in the contralateral eye. Fifteen patients received strabismus surgery, of whom 6 patients with monocular elevation deficiency (MED) underwent the standard Knapp procedure, with or without a horizontal deviation procedure. Fifteen cases were horizontally aligned within 5 prism dioptres (Δ). Six patients with MED (100%) had attained ≥25% elevation improvement after surgery, and the vertical deviation decreased from 25.83 Δ ± 4.92 Δ (range, 20 Δ-30 Δ) to 0.83 Δ ± 4.92 Δ after surgery (range, 0 Δ-10 Δ), for an improvement of 26.67 Δ ± 4.08 Δ (t = 16 P

AIM:To investigate the short-term effectiveness of orthokeratology(ortho-k)on controlling low-to-moderate myopic in Chinese children.METHODS: There were 271 subjects(271 eyes)enrolled in this study. In total, there were 141 cases aged 9.43±1.10 in the ortho-k group and the spherical equivalent refractive errors(SER)were -2.74±1.15D. The patients were examined at 1, 7, 30, and 90d after they started wearing the ortho-k lenses. There were 130 cases aged 9.37±1.00 enrolled in the control group, with the SER -2.88±1.39D, and the examinations occurred at 6, 12mo after they started wearing single-vision spectacles. Myopic progression was estimated from changes of axial length in both groups. The chi-square test, independent samples t-tests, paired t-tests, Spearman analysis were used to compare the data of the two groups. RESULTS: The axial elongation was 0.27±0.17mm in the ortho-k group after 1a which was significantly longer than that before wearing(PPPt-test). There was significant negative correlation between axial elongation and initial age in both groups during the one-year period(ortho-k group: rs=-0.309, Prs=-0.472,P0.36mm in 1a)were 38% in the ortho-k group and 76.5% in the control group, respectively; whereas those of the older group(aged 9.4～12.0)were lower, reaching 24.3% and 12.9% in the ortho-k and control groups. In patients with SER 5.00～6.00D, the axial elongation in ortho-k group was 57.1% lower than that in control group. CONCLUSION: Ortho-k lens is effective to control myopic progression in children with low-to-moderate myopia. In particular, it reduces the percentage of younger children with fast progression and has a better effect of controlling myopic progression with higher degrees of myopia.

In recent years, the Chinese government has highlighted the importance of adopting hog safety/quality traceability, and a growing amount of research continues to entice firms to adopt traceability systems. In this study, a survey was conducted on a sample of pig slaughtering and processing firms in Zhejiang, China through personal interviews and emails. The aim of this study was to examine the determinants of firm behavior on the implementation of voluntary traceability systems with more stringent standards and controls than those of the mandatory system in China. The results revealed that motivation based on product quality improvement, capital ability and role perception (business type) had significantly positive relationships with a firm's voluntary traceability. Other incentives, such as operation improvement, recall risk reduction, reduced occurrence of safety issues, and technical strength were not found to be supportive in our study. This study provides an opportunity to better understand the determinants of firm behavior on voluntary traceability, particularly in light of the fact that some Chinese firms are facing the threat of criminal action for the use of illegal additives and the abuse of Clenbuterol. Policy recommendations on encouraging the implementation of pork safety voluntary traceability by hog slaughtering and processing firms are also discussed.

Purpose. To report the clinical features and CT manifestations of giant pancreatic serous cystadenoma (≥10 cm). Methods. We retrospectively reviewed the clinical features and CT findings of 6 cases of this entity. Results. All 6 patients were symptomatic. The tumors were 10.2 cm–16.5 cm (median value, 13.0 cm). CT imaging revealed that all 6 cases showed microcystic appearances (n=5) or mixed microcystic and macrocystic appearances (n=1). Five patients with tumors at the distal end of the pancreas received distal pancreatectomy. Among these 5 patients, 2 patients underwent partial transverse colon resection or omentum resection due to close adhesion. One patient whose tumor was located in the pancreatic head underwent pancreaticoduodenectomy; however, due to encasement of the portal and superior mesenteric veins, the tumor was incompletely resected. One patient had abundant draining veins on the tumor surface and suffered large blood loss (700 mL). After 6–49 months of follow-up the 6 patients showed no tumor recurrence or signs of malignant transformation. Conclusions. Giant pancreatic serous cystadenoma necessitates surgical resection due to large size, symptoms, uncertain diagnosis, and adjacent organ compression. The relationship between the tumors and the neighboring organs needs to be carefully assessed before operation on CT image.