Investigation of a novel elastic-mechanical wheel transmission under light duty conditions

A novel 'Elastic Engagement and Friction Coupled' (EEFC) mechanical transmission has been proposed recently in which the power is transmitted through elastic tines on the surfaces of the driving and driven wheels. This study introduces new variations of EEFC mechanical wheel transmission ( broadly emulating a gear-pair) with small contact areas for use under light duty conditions. Because a drive of this type inevitably has a strong statistical component, theoretical analysis of the geometrical and mechanical relationships has been attempted by using linear modeling and empirical weightings. Several simple forms of the EEFC wheel transmission are tested under limiting ( slip) conditions for transmission force and transmission coefficients against normal load. Normalized standard deviation of these parameters is used to summarize noise performance. Models and experiments are in reasonable agreement, suggesting that the model parameters reflect important design considerations. EEFC transmissions appear well suited to force regimes of a few tenths of a newton and to have potential for use in, for example, millimetre-scale robots

Serum sex hormone binding globulin profile and its association with insulin resistance in Chinese peri-menopausal women

Wstęp: Celem badania było oznaczenie profilu stężeń globuliny wiążącej hormony płciowe (SHBG) w surowicy u Chinek będących w okresie okołomenopauzalnym oraz ocena korelacji tego profilu z parametrem insulinooporności HOMA-IR w tej szczególnej populacji. Materiał i metody: Przeprowadzono badanie przekrojowe metodą doboru grupowego z udziałem 1827 kobiet przebywających w szpitalu na rutynowych badaniach kontrolnych. Oznaczono profil stężeń SHBG i parametry statusu hormonalnego, parametry otyłości i parametry metaboliczne. Uczestniczki badania podzielono ze względu na wiek i status menstruacyjny na trzy grupy: grupę w okresie przedmenopauzalnym, grupę w okresie okołomenopauzalnym i grupę w okresie pomenopauzalnym. Wyniki: Stwierdzono, że stężenie SHBG w surowicy wykazuje ujemną korelację z BMI we wszystkich grupach i wzrasta z wiekiem kobiet w wieku reprodukcyjnym. Stężenie SHBG ulegało też, niezależnie od wieku, znamiennemu wzrostowi od początku zmian menopauzalnych, a następnie, po menopauzie, ulegało nieznacznemu zmniejszeniu. Po wzięciu poprawek na wiek i BMI, stwierdzono, że HOMA-IR u kobiet w okresie okołomenopauzalnym wykazuje ścisły związek wyłącznie z SHBG. Stwierdzono, że stężenie SHBG jest jedynym niezależnym istotnym determinantem HOMA-IR. Na podstawie analizy krzywej ROC dla predykcji insulinooporności na podstawie wartości HOMA-IR stwierdzono, że AUC dla SHBG osiąga wartość 0,816 (95% przedział ufności: 0,636–0,996). W przypadku kobiet w okresie okołomenopauzalnym najlepszą wartość odcięcia odróżniającą kobiety z insulinoopornością od kobiet bez insulinooporności jest 41,73 nmol/l przy czułości wynoszącej 81,4% i swoistości wynoszącej 87,5%. Wnioski: U Chinek w okresie okołomenopauzalnym niskie stężenie SHBG może stanowić niezależny czynnik ryzyka insulinooporności. (Endokrynol Pol 2013; 64 (3): 197–202)Introduction: The aim of this study was to measure serum sex hormone binding globulin (SHBG) profile in Chinese peri-menopausal women, and assess its correlation with insulin resistance (IR)-related parameter, namely HOMA-IR, in this special population. Material and methods: A cross-sectional study by the method of cluster sampling was performed in 1,827 women, who were in hospital for routine check-up. Serum SHBG profile and anthropometric indices of hormonal, adiposity, and metabolic variables were measured. According to their age and menstruation status, the subjects were divided into three groups: pre-menopause group, peri-menopause group, and post-menopause group. Results: Serum SHBG level was found to be negatively correlated with BMI in all groups and to increase in parallel with age in women of reproductive age. However, independently of age, it significantly increased from the onset of menopause transition, and slightly declined after menopause. After adjustment for age and BMI, HOMA-IR in peri-menopausal women was closely related only to SHBG. SHBG level was found to be the only independent significant determinant of HOMA-IR. On the basis of ROC curve analysis for the prediction of insulin resistance using HOMA-IR value, AUC for SHBG reached a value of 0.816 (0.636–0.996, 95% confidence interval). The best cutoff value that discriminates peri-menopausal women with or without insulin resistance is 41.73 nmol/L, with a sensitivity of 81.4% and a specificity of 87.5%. Conclusions: Low SHBG level may be an independent risk factor of insulin resistance in Chinese peri-menopausal women. (Endokrynol Pol 2013; 64 (3): 197–202

Analysis of the Electrical and Thermal Properties for Magnetic Fe3O4-Coated SiC-Filled Epoxy Composites.

Orderly arranged Silicon carbide (SiC)/epoxy (EP) composites were fabricated. SiC was made magnetically responsive by decorating the surface with iron oxide (Fe3O4) nanoparticles. Three treatment methods, including without magnetization, pre-magnetization and curing magnetization, were used to prepare SiC/EP composites with different filler distributions. Compared with unmodified SiC, magnetic SiC with core-shell structure was conducive to improve the breakdown strength of SiC/EP composites and the maximum enhancement rate was 20.86%. Among the three treatment methods, SiC/EP composites prepared in the curing-magnetization case had better comprehensive properties. Under the action of magnetic field, magnetic SiC were orderly oriented along the direction of an external field, thereby forming SiC chains. The magnetic alignment of SiC restricted the movement of EP macromolecules or polar groups to some extent, resulting in the decrease in the dielectric constant and dielectric loss. The SiC chains are equivalent to heat flow channels, which can improve the heat transfer efficiency, and the maximum improvement rate was 23.6%. The results prove that the orderly arrangement of SiC had a favorable effect on dielectric properties and thermal conductivity of SiC/EP composites. For future applications, the orderly arranged SiC/EP composites have potential for fabricating insulation materials in the power electronic device packaging field

Resveratrol Promotes Diabetic Wound Healing via SIRT1-FOXO1-c-Myc Signaling Pathway-Mediated Angiogenesis

Background/Aims: Diabetic non-healing skin ulcers represent a serious challenge in clinical practice, in which the hyperglycemia-induced disturbance of angiogenesis, and endothelial dysfunction play a crucial role. Resveratrol (RES), a silent information regulator 1 (SIRT1) agonist, can improve endothelial function and has strong pro-angiogenic properties, and has thus become a research focus for the treatment of diabetic non-healing skin ulcers; however, the underlying mechanism by which RES regulates these processes remains unclear. Therefore, the present study was intended to determine if RES exerts its observed protective role in diabetic wound healing by alleviating hyperglycemia-induced endothelial dysfunction and the disturbance of angiogenesis.Methods: We investigated the effects of RES on cell migration, cell proliferation, apoptosis, tube formation, and the underlying molecular mechanisms in 33 mM high glucose-stimulated human umbilical vein endothelial cells (HUVECs) by semi-quantitative RT-PCR, western blot analysis, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining, and immunofluorescence in vitro. We further explored the role of RES on endothelial dysfunction and wound healing disturbance in db/db mice by TUNEL staining, immunofluorescence, and photography in vivo.Results: We observed an obvious inhibition of hyperglycemia-triggered endothelial dysfunction and a disturbance of angiogenesis, followed by the promotion of diabetic wound healing via RES, along with restoration of the activity of the hyperglycemia-impaired SIRT1 signaling pathway. Pretreatment with EX-527, a SIRT1 inhibitor, abolished the RES-mediated endothelial protection and pro-angiogenesis action, and then delayed diabetic wound healing. Furthermore, examination of the overexpression of forkhead box O1 (FOXO1), a transcription factor substrate of SIRT1, in HUVECs and db/db mice revealed that RES activated SIRT1 to restore hyperglycemia-triggered endothelial dysfunction and disturbance of angiogenesis, followed by the promotion of diabetic wound healing in a c-Myc-dependent manner. Pretreatment with 10058-F4, a c-Myc inhibitor, repressed RES-mediated endothelial protection, angiogenesis, and diabetic wound healing.Conclusion: Our findings indicate that the positive role of RES in diabetic wound healing via its SIRT1-dependent endothelial protection and pro-angiogenic effects involves the inhibition of FOXO1 and the de-repression of c-Myc expression

Calcitriol restrains microglial M1 polarization and alleviates dopaminergic degeneration in hemiparkinsonian mice by boosting regulatory T‐cell expansion

Abstract Objective Vitamin D deficiency is a risk factor for Parkinson's disease (PD) and vitamin D supplementation robustly alleviates neurodegeneration in PD models. However, the mechanisms underlying this effect require further clarification. Current evidence suggests that harnessing regulatory T cells (Treg) may mitigate neuronal degeneration. In this study, we investigated the therapeutic effects of vitamin D receptor activation by calcitriol on PD, specifically focusing on its role in Treg. Methods Hemiparkinsonian mice model was established through the injection of 6‐OHDA into the striatum. Mice were pretreated with calcitriol before 6‐OHDA injection. The motor performance, dopaminergic neuronal survival, contents of dopamine, and dopamine metabolites were evaluated. The pro‐inflammatory cytokines levels, T‐cell infiltration, mRNA expression of indicated microglial M1/M2 phenotypic markers, and microglial marker in the midbrain were detected. Populations of Treg in the splenic tissues were assessed using a flow cytometry assay. PC61 monoclonal antibody was applied to deplete Treg in vivo. Results We show that calcitriol supplementation notably improved motor performance and reduced dopaminergic degeneration in the 6‐OHDA‐induced PD model. Mechanistically, calcitriol promoted anti‐inflammatory/neuroprotective Treg and inhibited pro‐inflammatory/neurodestructive effector T‐cell generation in this model. This process significantly inhibited T‐cell infiltration in the midbrain, restrained microglial activation, microglial M1 polarization, and decreased pro‐inflammatory cytokines release. This more favorable inflammatory microenvironment rescued dopaminergic degeneration. To further verify that the anti‐inflammatory effects of calcitriol are associated with Treg expansion, we applied an antibody‐mediated Treg depletion assay. As predicted, the anti‐inflammatory effects of calcitriol in the PD model were diminished following Treg depletion. Conclusion These findings suggest that calcitriol's anti‐inflammatory and neuroprotective effects in PD are associated with its potential to boost Treg expansion

Evaluation of the Expansion and Neuronal Differentiation Potency of Cultured Olfactory Epithelium Progenitor Cells from a Rat Model of Depression

Background: Olfactory impairment has been reported in patients with depression and in rodent models of depression. Olfactory epithelium (OE) is the only peripheral neural tissue connected to the brain that has the potential for self-renewal. We hypothesized the olfactory deficit during depression may be related to the dysfunction of OE progenitor cells. The aim of the present study was therefore to evaluate the expansion and neuronal differentiation potency of cultured OE progenitor cells obtained from a rat model of depression. Methods: Rats were exposed to chronic unpredictable mild stress procedures to establish a depressive-like state. Depressive-like behavior and olfactory sensing function were then evaluated and compared with control rats. Primary OE progenitor cells were cultured in vitro. The proliferation potency and survival of OE progenitor cells were assessed by 5-Ethynyl-2′-deoxyuridine staining and Cell Counting Kit-8 (CCK8), respectively, while cellular apoptosis was measured by flow cytometry. The neuronal differentiation potency of OE progenitor cells was evaluated by measurement of the protein and mRNA level of β-3 tubulin, a marker of neural cells. mRNA expression associated with neural stemness was examined by quantitative reverse transcription polymerase chain reaction (RT-PCR). Results: Depressive-like rats showed decreased olfactory function. OE progenitor cells from depressive-like rats showed reduced cell proliferation/survival and neuronal differentiation potency. Moreover, OE progenitor cells from depressive-like rats showed decreased expression of mRNA related to neural stemness. Conclusions: These results indicate the impaired function of OE progenitor cells may contribute to the olfactory deficit observed during depression. The OE may therefore provide a window for the study of depression

Design of a Polyhedral Helix Curve Meshing Reducer

The space curve meshing wheel (SCMW) is an innovative gear mechanism based on the space curve meshing theory, and the helix curve meshing wheel (HCMW) is the most common SCMW. In this study, we propose the polyhedral helix curve meshing reducer (HCMR), which is based on the HCMW group. The installation dimension chains of the HCMW pairs are described for different included-angle cases and the HCMW group is produced by combining HCMW pairs. Finally, a polyhedral HCMR is designed with a single input shaft and multiple output shafts, with an adjustable gear box, for which a trial version was produced. The polyhedral HCMR has good application prospects because of its compact structure, high design flexibility, and low cost

Does the Tax Cuts Policy Lower Firm Survival Risk? Evidence from China

This paper examines the effect of tax cuts policy on firm survival risk. We analyze a panel data of China’s listed companies over the period 20082021 based on two different techniques: Kaplan-Meier survival estimator and the Cox proportional hazards model. Our findings reveal that the tax cuts policy has positive and significant effect on improving firms’ survival probabilities. Moreover, compared with the income tax cuts, the value-added tax cuts play a more effective role on improving firms’ survival probability. By dividing firm locations into different regions, we also find that the tax cuts policy exerts a positive influence on firms’ survival probabilities in eastern region, while the positive effect in the central and western regions is relatively weaker. From the perspective of profitability heterogeneity, the results show that the beneficial effect from tax cuts policy on firm survival is more pronounced for firms with weaker profitability