Modal and harmonic response analysis of key components of robotic arm based on ANSYS

To study the problem of vibration of harmonic response of robotic arm under the load, a three-dimensional model of the frame of the robotic arm was created in the Solidworks, then the model was imported into ANSYS for modal analysis. We obtained the frequency of natural vibration and the effect of response of the key components of robotic arm by above analysis. The natural frequency of the robotic arm can be kept away from the frequency of vibration of machine completely, and thus poor working conditions caused by resonance can be avoided. Next the analysis of harmonic response was also performed on the basis of modal analysis. According to the above analysis we obtained displacement diagram and stress distribution diagram of harmonic response. The analysis has a referenced value to design and improve the structure of robotic arm

Multilevel Matrix Factor Model

Large-scale matrix data has been widely discovered and continuously studied in various fields recently. Considering the multi-level factor structure and utilizing the matrix structure, we propose a multilevel matrix factor model with both global and local factors. The global factors can affect all matrix times series, whereas the local factors are only allow to affect within each specific matrix time series. The estimation procedures can consistently estimate the factor loadings and determine the number of factors. We establish the asymptotic properties of the estimators. The simulation is presented to illustrate the performance of the proposed estimation method. We utilize the model to analyze eight indicators across 200 stocks from ten distinct industries, demonstrating the empirical utility of our proposed approach.Comment: 47 pages, 22 figure

Disturbance of the OPG/RANK/RANKL pathway and systemic inflammation in COPD patients with emphysema and osteoporosis

<p>Abstract</p> <p>Background</p> <p>Osteoporosis is one of the systemic features of COPD. A correlation between the emphysema phenotype of COPD and reduced bone mineral density (BMD) is suggested by some studies, however, the mechanisms underlying this relationship are unclear. Experimental studies indicate that IL-1β, IL-6 and TNF-α may play important roles in the etiology of both osteoporosis and emphysema. The OPG/RANK/RANKL system is an important regulator of bone metabolism, and participates in the development of post-menopausal osteoporosis. Whether the OPG/RANK/RANKL pathway is involved in the pathogenesis of osteoporosis in COPD has not been studied.</p> <p>Methods</p> <p>Eighty male patients (current or former smokers) completed a chest CT scan, pulmonary function test, dual x-ray absorptiometry measurements and questionnaires. Among these subjects, thirty patients with normal BMD and thirty patients with low BMD were selected randomly for measurement of IL-1β, IL-6, TNF-α (flow cytometry) and OPG/RANK/RANKL (ELISA). Twenty age-matched healthy volunteers were recruited as controls.</p> <p>Results</p> <p>Among these eighty patients, thirty-six had normal BMD and forty-four had low BMD. Age, BMI and CAT score showed significant differences between these two COPD groups (<it>p </it>< 0.05). The low-attenuation area (LAA%) in the lungs of COPD patients was negatively correlated with lumbar vertebral BMD (r = 0.741; <it>p </it>< 0.0001). Forward logistic regression analysis showed that only LAA% (<it>p </it>= 0.005) and BMI (<it>p </it>= 0.009) were selected as explanatory variables. The level of IL-1β was significantly higher in the COPD patients as compared to the normal controls (<it>p </it>< 0.05), but the difference between the two COPD groups did not reach significance. The levels of IL-6 and TNF-α among the three groups were significantly different (<it>p </it>< 0.05). The level of RANKL and the RANKL/OPG ratio were significantly higher in COPD patients with low BMD compared to those with normal BMD and the normal controls (<it>p </it>< 0.05), and correlated negatively with lumbar vertebral BMD, but positively with LAA%.</p> <p>Conclusions</p> <p>Radiographic emphysema is correlated with low BMD in current and former smokers with COPD. IL-1β, IL-6, TNF-α, and the osteoporosis-related protein system OPG/RANK/RANKL may have some synergetic effects on emphysema and bone loss in COPD.</p

Swimming exercise ameliorates hypertension-induced kidney dysfunction via alleviating renal interstitial fibrosis and apoptosis

Background: Hypertensive nephropathy is one of the major causes of ESRD. Exercise has been considered a nonpathological therapy for hypertension and its complications, yet mechanisms remain unclear. We sought to investigate whether periodic swimming could ameliorate hypertension-induced kidney dysfunction and its underlying mechanisms. Methods: Four-week male spontaneously hypertensive rats (SHRs) were randomly divided into the hypertension group (SHR, n = 8) and exercise group (SE, n = 8, 60 min swimming/day, 6 days per week, for 8 weeks). Wistar-Kyoto rats (WKY, n = 8) were served as a sedentary normotensive group. Bodyweight and blood pressure (BP) were recorded weekly. After 8-week sedentary or swimming exercise, lipids profile, BUN, and Cr were measured. The renal interstitial fibrosis was examined by the histopathological analysis using Masson\u27s trichrome staining and hematoxylin and eosin staining. The kidney cell apoptosis was tested by TUNEL staining. The expressions of critical proteins responsible for the TGF-β1/Smad signaling of fibrosis, that is, TGF-β1, Smad2/3, and Smad7, as well as apoptosis related proteins, Bax and Bcl-2 in kidney cortex tissues were measured. Results: The 8-week swimming exercise reduced BP and bodyweight, lowered concentrations of BUN, and serum Cr, compared with SHR. Exercise remarkably inhibited hypertension-induced tubular degeneration, cellular cluster, and tubular cell swelling as well as glomerular degeneration in the kidney cortical tissues, attenuated renal interstitial fibrosis, and renal cell apoptosis. Moreover, expressions of TGF-β1, Smad2/3, and Bax were higher in the SHR than the WKY, which were significantly suppressed by the exercise. In contrast, hypertension-reduced expressions of Smad7 and Bcl-2 were enhanced by the swimming exercise. Strong correlations were found between kidney function indices, blood lipids, and key protein expressions. Conclusion: Our results demonstrate beneficial effects of the periodic swimming on ameliorating hypertension-induced kidney dysfunction highlighting the potential of swimming exercise as a nonpathological therapy for early prevention of hypertension-caused kidney diseases

Functional Impact Of 14 Single Nucleotide Polymorphisms Causing Missense Mutations Of Human α7 Nicotinic Receptor

The α7nicotinic receptor (nAChR) is a major subtype of the nAChRs in the central nervous system, and the receptor plays an important role in brain function. In the dbSNP database, there are 55 single nucleotide polymorphisms (SNPs) that cause missense mutations of the human α7nAChR in the coding region. In this study, we tested the impact of 14 SNPs that cause missense mutations in the agonist binding site or the coupling region between binding site and channel gate on the receptor function. The wild type or mutant receptors were expressed or co-expressed in Xenopus oocytes, and the agonist-induced currents were tested using two-electrode voltage clamp. Our results demonstrated that 6 mutants were nonfunctional, 4 mutants had reduced current expression, and 1 mutants altered ACh and nicotine efficacy in the opposite direction, and one additional mutant had slightly reduced agonist sensitivity. Interestingly, the function of most of these nonfunctional mutants could be rescued by α7nAChR positive allosteric modulator PNU-120596 and agonist-PAM 4BP-TQS. Finally, when coexpressed with the wild type, the nonfunctional mutants could also influence the receptor function. These changes of the receptor properties by the mutations could potentially have an impact on the physiological function of the α7nAChR-mediated cholinergic synaptic transmission and anti-inflammatory effects in the human SNP carriers. Rescuing the nonfunctional mutants could provide a novel way to treat the related disorders. Copyright