Arborinol methyl ether from Areca catechu L.

The title compound isolated from Areca catechu L. (common name: arborinol methyl ether; a member of the arborane family) was established as 3α-methoxyarbor-9(11)-ene, C31H52O. Rings A/B/C/D assume a chair conformation, while ring E has an envelope conformation. The absolute configuration was determined to be (3R,5R,8S,10S,13R,14S,17S,18S, 21S) by analysis of Bijvoet pairs based on resonant scattering of light atoms, yielding a Hooft parameter y of −0.03 (3)

Tai Chi Can Improve Postural Stability as Measured by Resistance to Perturbation Related to Upper Limb Movement Among Healthy Older Adults

Purpose: The aim of the study was to examine the effects of Tai Chi (TC) training on postural control when upright standing was perturbed by upper limb movement. Methods: Three groups, TC, Brisk walk (BW), and sedentary (SE), of thirty-six participants aged from 65 to 75 years were recruited from local community centers. Participants performed static balance task (quiet standing for 30 s with eyes open and closed) and fitting task (two different reaching distances X three different opening sizes to fit objects through). During tasks, the COP data was recorded while standing on the force plate. Criteria measures calculated from COP data were the maximum displacement in anterior-posterior (AP) and medial-lateral (ML) directions, the 95% confidence ellipse area (95% area), and the mean velocity. Results: No significant effect was observed in the static balance task. For fitting tasks, the group effect was observed in all directions on COP 95% area (p \u3c 0.05) and the TC group showed reduced area. The tests of subject contrasts showed significant trends for reaching different distances and fitting different openings conditions in all directions, the 95% area, and the mean velocity (p \u3c 0.05). Conclusion: Compared to the other two groups, long-term TC exercise helps in reducing the effects of upper body perturbation as measured by posture sway

Nonlinear Jordan triple derivable mapping on ∗-type trivial extension algebras

The aim of the paper was to give a description of nonlinear Jordan triple derivable mappings on trivial extension algebras. We proved that every nonlinear Jordan triple derivable mapping on a $2$-torsion free $*$-type trivial extension algebra is a sum of an additive derivation and an additive antiderivation. As an application, nonlinear Jordan triple derivable mappings on triangular algebras were characterized

Tai Chi Can Improve Postural Stability as Measured by Resistance to Perturbation Related to Upper Limb Movement among Healthy Older Adults

Purpose. The aim of the study was to examine the effects of Tai Chi (TC) training on postural control when upright standing was perturbed by upper limb movement. Methods. Three groups, TC, Brisk walk (BW), and sedentary (SE), of thirty-six participants aged from 65 to 75 years were recruited from local community centers. Participants performed static balance task (quiet standing for 30 s with eyes open and closed) and fitting task (two different reaching distances X three different opening sizes to fit objects through). During tasks, the COP data was recorded while standing on the force plate. Criteria measures calculated from COP data were the maximum displacement in anterior-posterior (AP) and medial-lateral (ML) directions, the 95% confidence ellipse area (95% area), and the mean velocity. Results. No significant effect was observed in the static balance task. For fitting tasks, the group effect was observed in all directions on COP 95% area (p<0.05) and the TC group showed reduced area. The tests of subject contrasts showed significant trends for reaching different distances and fitting different openings conditions in all directions, the 95% area, and the mean velocity (p<0.05). Conclusion. Compared to the other two groups, long-term TC exercise helps in reducing the effects of upper body perturbation as measured by posture sway

The Effect of Tai Chi Exercise on Postural Time-to-Contact in Manual Fitting Task among Older Adults

Background A fall would impact elderly population’s quality of life, which associate with diminished physical and psychological function, and can even be life-threatening. Tai Chi has been used to improve age-related postural instability in locomotion. However, it does not fully explain the mechanism of a lower risk of falling among the Tai Chi population compared to other healthy older adults. Research question The maintenance of postural stability is more complicated than minimizing postural movements. Postural time to contact is an important temporal measure of postural stability under fitting tasks, which might further clarify the benefits of long term Tai Chi exercise. Methods Participants were required to fit a block (90 × 90 mm) through two different openings (130 × 130 mm and 100 × 100 mm) at two different distances (arm’s length or 130 % of arm’s length). Kistler forceplate and Vicon system were used to collect center of pressure and kinematic data, respectively. Postural time to contact was used to assess instantaneous perturbation for postural system. Results Tai Chi group exhibited significant longer postural time to contact in quiet standing and shorter postural time to contact in fitting tasks, expecting for close-small condition, compared to the brisk walking and sedentary groups (p \u3c .05). In addition, both large and small opening condition, Tai Chi group showed a shorter postural time to contact than brisk walking and sedentary groups (p \u3c .0001). Significance Long term Tai Chi exercise would promote the regulation of posture and decrease the postural constrain to increase the overall stability when performing fitting tasks. Therefore, Tai Chi exercise can be considered as a feasible method to enhance postural control and stability in older adult

High Specific Capacitance of the Electrodeposited MnO2 on Porous Foam Nickel Soaked in Alcohol and its Dependence on Precursor Concentration

In this work, we used the mixed solution of manganese acetate and sodium sulfate to deposit manganese dioxide on the three-dimensional porous nickel foam that was previously soaked in alcohol, and then the effects of solution concentrations on their capacitance properties were investigated. The surface morphology, microstructure, elemental valence and other information of the material were observed by scanning electron microscope (SEM), Transmission Electron Microscope (TEM), X-ray photoelectron spectroscopy (XPS), etc. The electrochemical properties of the material were tested by Galvanostatic charge-discharge (GCD), Cyclic Voltammetry (CV), Chronoamperometry (CA), Electrochemical impedance spectroscopy (EIS), etc. The MnO2 electrode prepared at lower concentrations can respectively reach a specific capacitance of 529.5 F g&minus;1 and 237.3 F g&minus;1 at the current density of 1 A g&minus;1 and 10 A g&minus;1, and after 2000 cycles, the capacity retention rate was still 79.8% of the initial capacitance, and the energy density can even reach 59.4 Wh Kg&minus;1, while at the same time, it also has a lower electrochemical impedance (Rs = 1.18 Ω, Rct = 0.84 Ω)

Higher Jordan triple derivations on ∗-type trivial extension algebras

In this paper, we investigated the problem of describing the form of higher Jordan triple derivations on trivial extension algebras. We show that every higher Jordan triple derivation on a $2$-torsion free $*$-type trivial extension algebra is a sum of a higher derivation and a higher anti-derivation. As for its applications, higher Jordan triple derivations on triangular algebras are characterized

A Unified Model for BDS Wide Area and Local Area Augmentation Positioning Based on Raw Observations

In this study, a unified model for BeiDou Navigation Satellite System (BDS) wide area and local area augmentation positioning based on raw observations has been proposed. Applying this model, both the Real-Time Kinematic (RTK) and Precise Point Positioning (PPP) service can be realized by performing different corrections at the user end. This algorithm was assessed and validated with the BDS data collected at four regional stations from Day of Year (DOY) 080 to 083 of 2016. When the users are located within the local reference network, the fast and high precision RTK service can be achieved using the regional observation corrections, revealing a convergence time of about several seconds and a precision of about 2–3 cm. For the users out of the regional reference network, the global broadcast State-Space Represented (SSR) corrections can be utilized to realize the global PPP service which shows a convergence time of about 25 min for achieving an accuracy of 10 cm. With this unified model, it can not only integrate the Network RTK (NRTK) and PPP into a seamless positioning service, but also recover the ionosphere Vertical Total Electronic Content (VTEC) and Differential Code Bias (DCB) values that are useful for the ionosphere monitoring and modeling

Considering Inter-Frequency Clock Bias for BDS Triple-Frequency Precise Point Positioning

The joint use of multi-frequency signals brings new prospects for precise positioning and has become a trend in Global Navigation Satellite System (GNSS) development. However, a new type of inter-frequency clock bias (IFCB), namely the difference between satellite clocks computed with different ionospheric-free carrier phase combinations, was noticed. Consequently, the B1/B3 precise point positioning (PPP) cannot directly use the current B1/B2 clock products. Datasets from 35 globally distributed stations are employed to investigate the IFCB. For new generation BeiDou Navigation Satellite System (BDS) satellites, namely BDS-3 satellites, the IFCB between B1/B2a and B1/B3 satellite clocks, between B1/B2b and B1/B3 satellite clocks, between B1C/B2a and B1C/B3 satellite clocks, and between B1C/B2b and B1C/B3 satellite clocks is analyzed, and no significant IFCB variations can be observed. The IFCB between B1/B2 and B1/B3 satellite clocks for BDS-2 satellites varies with time, and the IFCB variations are generally confined to peak amplitudes of about 5 cm. The IFCB of BDS-2 satellites exhibits periodic signal, and the accuracy of prediction for IFCB, namely the root mean square (RMS) statistic of the difference between predicted and estimated IFCB values, is 1.2 cm. A triple-frequency PPP model with consideration of IFCB is developed. Compared with B1/B2-based PPP, the positioning accuracy of triple-frequency PPP with BDS-2 satellites can be improved by 12%, 25% and 10% in east, north and vertical directions, respectively

Drug resistance evolution in patients with human immunodeficiency virus-1 under long-term antiretroviral treatment-failure in Yunnan Province, China

Abstract Background Understanding the prevalence and evolution of HIV-1 drug resistance (DR) and associated mutation patterns is critical to implementing free antiretroviral therapy in Yunnan, the first antiretroviral treatment location in China. Here We provide a basis for understanding the occurrence and development of HIV-1 resistance in Yunnan and a theoretical foundational for strategy to delay HIV-1 drug resistance and achieve successful individualized treatment. Methods Plasma samples from different cities/prefectures were collected at Yunnan Provincial Hospital of Infectious Disease from January 2010 to September 2016, and those from drug-resistant individuals were genotyped using in-house assays, 88 patients were selected for the study who had been on treatment for ≥6 months (and for whom drug resistance was then measured), and each patient had at least 3 genotype resistance tests and who were enrolled to analyze mutation and evolution of HIV resistance. Results 264 Pol sequences of 88 patients were obtained. Drug resistance levels to eight drugs increased to varying degrees with prolonged treatment. Resistance to efavirenz (EFV) and etravirine (ETR) showed the highest change, comparisons of resistant changes to second and first and to third and second agents showed altered level of drug resistance were 25 and 20 cases, 28 and 18 cases, respectively. The smallest change was Lopinavir/Ritonavir (LPV/r) present 2 and 3 cases; Resistance to lamivudine (3TC) and lopinavir/ritonavir (LPV/r) was high among patients detected thrice, whereas other drugs were distributed in all resistance levels. M184 V/I (26.14%), T69S (11.36%), and T215Y/I (10.23%) mutations were the most common in nucleoside reverse transcriptase inhibitors (NRTIs), and K103 N/R/S (21.59%), V179D/E (20.45%) in Non-NRTIs (NNRTIs). Furthermore, L10 V/F/I (6.82%), A71V (4.55%), and I54V (4.55%) mutations were common in protease inhibitors (PIs). Conclusions We found dynamic genotypic changes in HIV-1 drug-resistance in Yunnan, with prolonged treatment, and drug resistance was inevitable. However, resistance to different drugs occurred at varying times, and mutation site emergence was the main cause. These findings enhance our understanding of evolution and regulation, and are valuable for developing HIV-1 DR prevention strategies in Yunnan