EFFECTS OF MOVEMENT RANGE ON PEAK TORQUE DURING ISOKINETIC KNEE FLEXION AND EXTENSION

INTRODUCTION: The knee joint is one of the biggest and most complex joints of the body. Optimal function of the knee joint is closely related with the physical performance and the outcome of sporting activity. Consequently, there have been many studies related to the muscles of the knee joint. The majority of these have focused on 90°range of knee movement, and the same start-angle and end-angle. However, during normal exertion and in sports, different actions require a different range of movement of the knee joint. In addition, the muscular force and velocity are also different. Therefore, in this paper, the biomechanical characteristics of knee muscles in different ranges were studied

Maintenance of Circulation Anomalies during the 1988 Drought and 1993 Floods over the United States

The large-scale circulation anomalies associated with the 1988 drought and the 1993 floods are investigated with the National Centers for Environmental Prediction Reanalysis data and a linear stationary wave model. The transient vorticity and thermal forcings are explicitly calculated and the diabatic heating is derived as a residual in the thermodynamic energy equation. Using the April–June (AMJ) data for 1988, and June–August (JJA) data for 1993, the linear stationary wave model is able to reproduce the main features of the geopotential height anomaly for the two seasons when all forcings are included. This provides a basis for further investigation of stationary wave response to different forcing mechanisms using the linear model. Within the linear model framework, the linear model responses to different forcings are examined separately. The results indicate that the 1988 anomaly over the United States is a result of both the diabatic heating and the transient vorticity and thermal forcings. The large anticyclonic anomalies over the North Pacific and Canada are forced mainly by the diabatic heating. The 1993 anomaly, however, is dominated by the response to transient vorticity forcing. By further separating the linear model responses to regional diabatic heating anomalies in 1988, the results indicate that the western North Pacific heating is entirely responsible for the anticyclonic center over the North Pacific, which causes the northward shift and intensification of the Pacific jet stream. The eastern North Pacific heating/cooling couplet is the most important for maintaining the North American circulation anomaly. The tropical eastern Pacific cooling/heating anomalies associated with the La Nina condition have negligible influence on the North American circulation. In 1993, the strong diabatic heating over the North American continent largely compensates the effect of the cooling over the North Pacific. The dynamics of the AMJ and JJA climate is further explored by calculating its Green’s function for both diabatic heating and vorticity forcing. The results again show negligible influence from the equatorial Pacific. The most effective location for diabatic heating to generate a North American circulation anomaly is along the west coast of North America, where the zonal wind is relatively weak. There is little sensitivity in the Green’s function solution to the different basic states

A robust empirical seasonal prediction of winter NAO and surface climate

A key determinant of winter weather and climate in Europe and North America is the North Atlantic Oscillation (NAO), the dominant mode of atmospheric variability in the Atlantic domain. Skilful seasonal forecasting of the surface climate in both Europe and North America is reflected largely in how accurately models can predict the NAO. Most dynamical models, however, have limited skill in seasonal forecasts of the winter NAO. A new empirical model is proposed for the seasonal forecast of the winter NAO that exhibits higher skill than current dynamical models. The empirical model provides robust and skilful prediction of the December-January-February (DJF) mean NAO index using a multiple linear regression (MLR) technique with autumn conditions of sea-ice concentration, stratospheric circulation, and sea-surface temperature. The predictability is, for the most part, derived from the relatively long persistence of sea ice in the autumn. The lower stratospheric circulation and sea-surface temperature appear to play more indirect roles through a series of feedbacks among systems driving NAO evolution. This MLR model also provides skilful seasonal outlooks of winter surface temperature and precipitation over many regions of Eurasia and eastern North America

Stratosphere-Troposphere Coupling Leading to Extended Seasonal Predictability of Summer North Atlantic Oscillation and Boreal Climate

The boreal summer climate is of significant societal importance and is trending toward increased risks of extreme climate events such as heatwaves. The summer North Atlantic Oscillation, as the primary mode of atmospheric variability in the northern hemisphere, has been long considered lacking predictability on seasonal time scales. Here we show that the summer North Atlantic Oscillation is predictable with a 2-month lead for the recent decades. The primary predictor is the March North Atlantic jet strength, which is correlated with the summer North Atlantic Oscillation index at a correlation coefficient of 0.66 over 1979–2018. Spring stratosphere-troposphere coupling plays a critical role in this extended predictability from spring to summer, in contrast to the common knowledge that this dynamical coupling is relatively inactive outside the winter season. These results may bring sound prospects for summer seasonal prediction of boreal climate that benefits the energy and public health sectors

A novel adaptive particle swarm optimization algorithm based high precision parameter identification and state estimation of lithium-ion battery.

Lithium-ion batteries are widely used in new energy vehicles, energy storage systems, aerospace and other fields because of their high energy density, long cycle life and high-cost performance. Accurate equivalent modeling, adaptive internal state characterization and accurate state of charge estimation are the cornerstones of expanding the application market of lithium-ion batteries. According to the highly nonlinear operating characteristics of lithium-ion batteries, the Thevenin equivalent model is used to characterize the operating characteristics of lithium-ion batteries, particle swarm optimization algorithm is used to process the measured data, and adaptive optimization strategy is added to improve the global search ability of particles, and the parameters of the model are identified innovatively. Combined with extended Kalman algorithm and Sage-Husa filtering algorithm, the state-of-charge estimation model of lithium ion battery is constructed. Aiming at the influence of fixed and inaccurate noise initial value in traditional Kalman filtering algorithm on SOC estimation results, Sage-Husa algorithm is used to adaptively correct system noise. The experimental results under HPPC condition show that the maximum error of the model is less than 1.5%. Simulation results of SOC estimation algorithm under two different operating conditions show that the maximum estimation error of adaptive extended Kalman algorithm is less than 0.05, which realizes high-precision lithium battery model parameter identification and high-precision state-of-charge estimation

Anisotropic thermal expansion of monoclinic potassium lutetium tungstate single crystals

The anisotropic thermal expansion of a single crystal of KLu WO4 2 KLuW , obtained by the top-seeded solution growth method, has been investigated over a wide temperature range 50– 600 °C . The linear thermal-expansion tensor has been determined and its principal X, Y, and Z axes are in the 705 , 010 , and 107 crystallographic directions, respectively. The principal thermal-expansion coefficients I, II, and III are 12.8 10−6, 7.8 10−6, and 22.2 10−6 K−1, respectively. The principal axis with maximum thermal expansion Z with III=22.2 10−6 is located at 10.37° from the c axis. In comparison with KGd WO4 2 and KYb WO4 2, the thermal-expansion anisotropy of KLuW is weaker and therefore optical-quality crystals are easier to obtain than with KGdW and KYbW from a thermal-expansion standpoint

Recovery and treatment of fracturing flowback fluids in the Sulige Gasfield, Ordos Basin

AbstractCentralized and group well deployment and factory-like fracturing techniques are adopted for low-permeability tight sandstone reservoirs in the Sulige Gasfield, Ordos Basin, so as to realize its efficient and economic development. However, environmental protection is faced with grim situations because fluid delivery rises abruptly on site in a short time due to centralized fracturing of the well group. Based on the characteristics of gas testing after fracturing in this gas field, a fracturing flowback fluid recovery and treatment method suitable for the Sulige Gasfield has been developed with the landform features of this area taken into account. Firstly, a high-efficiency well-to-well fracturing flowback fluid recovery and reutilization technique was developed with multi-effect surfactant polymer recoverable fracturing fluid system as the core, and in virtue of this technique, the treatment efficiency of conventional guar gum fracturing fluid system is increased. Secondly, for recovering and treating the end fluids on the well sites, a fine fracturing flowback fluid recovery and treatment technique has been worked out with “coagulation and precipitation, filtration and disinfection, and sludge dewatering” as the main part. Owing to the application of this method, the on-site water resource utilization ratio has been increased and environmental protection pressure concerned with fracturing operation has been relieved. In 2014, field tests were performed in 62 wells of 10 well groups, with 32980 m3 cumulative treated flowback fluid, 17160 m3 reutilization volume and reutilization ratio over 70%. Obviously, remarkable social and economical benefits are thus realized

Probiotic Characteristics of Human-Residential Bifidobacterium longum subsp. longum Strains

This study was conducted to isolate and identify Bifidobacterium from the feces of Kazakh school-age children in Yining, Xinjiang and evaluate the in vitro probiotic characteristics of B. longum subsp. longum isolates. By groEL gene sequencing and repetitive element sequence-based polymerase chain reaction (rep-PCR) fingerprinting, 416 Bifidobacterium strains were identified to belong to B. longum, B. bifidum, B. pseudocatenulatum, B. catenulatum and B. breve. According to the fingerprints of B. longum subsp. longum, 27 genotypes showed genetic differences between individual strains and the coexistence of multiple strains in the gut was found. The in vitro experimental results showed that out of 27 representative strains, strains 2B3-21, 1B23-11, 2B33-3, and 1B68-16 were optimal in acid and bile salt tolerance, strains 1B68-16, 2B13-5, 2B33-3, and 1B39-2 had broad-spectrum antibacterial properties, and strains 1B38-1, 2B33-3, 1B68-16, and 2B13-28 showed a strong antioxidant capacity. Considering the antibiotic resistance of all strains and their ability to utilize plant-derived glycans, strains 1B38-1 and 2B13-28 were selected to assess their in vivo probiotic potentials. This study may lay the foundation for the development of excellent probiotics and related products for populations from specific areas

Changes of Circulating Transforming Growth Factor-²1 Level During Radiation Therapy Are Correlated with the Prognosis of Locally Advanced Non-small Cell Lung Cancer

IntroductionWe hypothesized that plasma transforming growth factor-²1 (TGF-²1) level and its dynamic change are correlated with the prognosis of locally advanced non-small cell lung cancer (NSCLC) treated with radiation therapy (RT).MethodsPatients with stage IIIA or IIIB NSCLC treated with RT with or without chemotherapy were eligible for this study. Platelet poor plasma was collected from each patient within 1 week before RT (pre-RT) and at the 4th week during RT (during-RT). TGF-²1 level was measured with enzyme-linked immunosorbent assay. The primary end point was overall survival (OS) and the secondary end point was progression-free survival (PFS). Kaplan-Meier and Cox regression were used for risk factor evaluation.ResultsA total of 65 patients were eligible for the study. The median OS and PFS were 17.7 and 13.7 months, respectively. In univariate analysis, performance status, weight loss, radiation dose, and TGF-²1 ratio (during-RT/pre-RT TGF-²1 level) were all significantly correlated with OS. In the multivariate analysis, performance status, radiation dose, and TGF-²1 ratio were still significantly correlated with OS. The median OS was 30.7 months for patients with TGF-²1 ratio ≤1 versus 13.3 months for those with TGF-²1 ratio more than 1 (p = 0.0029); and the median PFS was 16.8 months versus 7.2 months, respectively (p = 0.010).ConclusionsIn locally advanced NSCLC, the decrease of TGF-²1 level during RT is correlated with favorable prognosis