EMG median frequency changes in the neck–shoulder stabilizers of symptomatic office workers when challenged by different physical stressors

The problem of work-related neck and upper limb disorders among computer users has been reported extensively in the literature, and commonly cited risk factors include static posture, speed and force of keyboard operation. The present study examined changes in median frequency (MF) of the neck–shoulder muscles in symptomatic and asymptomatic office workers when they were exposed to these three physical stressors.

A quasi-experimental Case–Control design was used to examine MF changes in two groups of female office workers when they were subjected to controlled doses of computer work involving prolonged static posture, increased typing speed and increased typing force. The MF of four major neck–shoulder muscles were examined bilaterally and compared between groups.

The MF changes over time-at-task did not clearly illustrate any muscle fatigue mechanism. However, Case Group consistently showed trends for higher MF than the Control Group, and this pattern was observed in response to all three physical stressors. The consistent group differences in MF suggest different muscle recruitment strategies between symptomatic and asymptomatic office workers. These results implied that symptomatic individuals had altered motor control, which may have important implications in understanding the etiology of work-related musculoskeletal disorders.     

新的天然免疫保护分子——PLUNC家族蛋白

在呼吸道上皮与消化道上皮的表面,覆盖有一层由免疫保护分子所组成的蛋白质混合物,在上皮组织与外界各种信号之间,它们起着信号传递中介与信号执行分子的作用.我们新克隆的NASG基因为这一混合物添加了新的成员,对其结构与功能分析表明:它属于腭、肺及鼻咽上皮克隆（PLUNC）家族中SPLUNC1的全新转录本.目前发现人类PLUNC家族至少有8个以上成员,分布在人类20号染色体大约300 kb的狭窄区域,它们具有杀菌\渗透增强蛋白结构域,在进化上高度保守,每个成员分别在呼吸道上皮的不同部位特异性表达,具有潜在的结合细菌脂多糖的功能,能对外来物理及化学刺激做出反应,以分泌蛋白的形式进入鼻咽分泌物或唾液中,部分家族成员可能具有抗微生物、清除有害化学物质、抗肿瘤等多重功效.以上说明,PLUNC家族可能是上呼吸道的一种新的天然免疫保护分子,在维持上呼吸道的正常生理活动中起重要作用.     

Stratification and diel activity of arthropods in a lowland rainforest in Gabon

The abundance, activity and species richness of arthropods, particularly of insect herbivores, were investigated in the upper canopy and understorey of a lowland rainforest at La Makandé, Gabon. In total 14 161 arthropods were collected with beating, flight interception and sticky traps, from six canopy sites, during the day and at night, from mid-January to mid-March 1999. The effects of stratum were most important, representing between 40 and 70% of the explained variance in arthropod distribution. Site effects represented between 20 and 40% of the variance and emphasized the néed for replication of sampling among canopy sites. Time effects (diel activity) explained a much lower percentage of variance (6–9%). The density and abundance of many arthropod taxa and species were significantly higher in the upper canopy than in the understorey. Arthropod activity was also higher during the day than at night. In particular, insect herbivores were 2.5 times more abundant and twice as speciose in the upper canopy than in the understorey, a probable response to the greater and more diverse food resources in the former stratum. Faunal overlap between the upper canopy and understorey was low. The most dissimilar herbivore communities foraged in the understorey at night and the upper canopy during the day. Further, a taxonomic study of a species-rich genus of herbivore collected there (Agrilus , Coleoptera Buprestidae) confirmed that the fauna of the upper canopy was different, diverse and very poorly known in comparison to that of the understorey. Herbivore turnover between day and night was rather high in the upper canopy and no strong influx of insect herbivores from lower foliage to the upper canopy was detected at night. This suggests that insect herbivores of the upper canopy may be resident and well adapted to environmental conditions there.     

The upper Moscovian and basal Kasimovian (Pennsylvanian) of Central European Russia: Facies,subaerial exposures and depositional model

Summary The type upper Moscovian-basal Kasimovian argillaceous-carbonate succession of central European Russia contains regionally traced cyclothem-bounded subaerial exposure horizons (geosols) represented mainly by rendzina-type palaeosols. Palaeokarst profiles occurrarely and grade laterally to palaeosols. Composite subaerial profiles divided by one or two thin marine beds are called ‘multiple geosols’. The biofaces structure of the studied succession is defined by brachiopod and fusulinoid biofaces. The heterogeneous Choristites biofacies characterizes openmarine intervals, which constitute the bulk of the succession, and is defined by presence of Choristites. The Meekella biofacies with monospecific concentrations of Meekella shells and extreme rarity of other brachiopods characterises restricted peritidal intervals which commonly constitute the terminal regressive parts of major cyclothems. Three fusulinoid biofacies defined by Baranova and Kabanov (2003) include restricted peritidal Biofacies 1 with only small fusulinoids Fusiella and Schubertella present, open shoal-to-subtidal Biofacies 2 with the richest fusulinoid assemblages, and the most offshore Biofacies 3 with less diverse, sometimes Hemifusulina-dominated, fusulinoid assemblages. Bioturbation patterns and ichnofossils allow recognition of deeper subtidal Zoophycos and shallower non-Zoophycos ichnofacies. Among the latter, shallowest subtidal facies are characterized by presence of thalassinoid burrows. Intertidal laminated lithofacies with suppressed bioturbation contain Skolithos burrows. Seventeen lithofacies are recognized. Terrestrial lithofacies include topclays (upper clayey palaeosol horizons) and aeolian grainstones. Restricted peritidal lithofacies include cross-stratified skeletal-peloidal grainstones, fine-grained laminated grainstones-mudstones, and lagoonal mudstones. Open shoal lithofacies include ooidal grainstones (rare, only in Podolskian) and coarse skeletal-peloidal grainstones. The open subtidal lithofacies include skeletal packstones-rudstones, shallow subtidal packstones-wackestones, deeper subtidal packstones-wackestones, Ivanovia boundstones (only in Podolskian), proximal tempestites, distal tempestites, and skeletal wackestones-mudstones. The fossiliferous shale lithofacies is a miscellaneous group of marine shales lacking distinct features of the above-listed lithofacies. Conglomerates of cyclothem bases that are regarded as early transgressive lithofacies are variable in their palaeoenvironmental position and are characterized by concentrated pebbles derived from palaeosol reworking. The shallowest subtidal lithofacies of fine packstones-grainstones is considered as transitional between open subtidal and restricted peritidal lithofacies. The origin of stratiform dolostones is shown to be early diagenetic in the subsurface. The depositional model involves a shallow and broad epicontinental ramp, where through water circulation prevented stratification of the water column and allowed large skeletal benthos to colonize the entire spectrum of depositional environments. Storms are thought to be the principal water-mixing agent. The anti-estuarine circulation carrying oxygenated waters down-ward may explain the lack of anoxic features in the deepest facies that may have formed below storm wave base.     

A large impact of tropical biomass burning on CO and CO2 in the upper troposphere

A large interannual variation of biomass burning emissions from Southeast Asia is asso-ciated with the ENSO events. During 1997/98 and 1994 El Nino years, uncontrolled wildfires of tropical rainforests and peat lands in Indonesia were enlarged due to a long drought. EnhancedCO injection into the upper troposphere from the intense Indonesian fires was clearly observed in the 8-year measurements from a regular flask sampling over the western Pacific using a JAL air-liner between Australia and Japan. This airliner observation also revealed that upper tropospheric CO_2 cycle largely changed during the 1997 El Nino year due partly to the biomass burning emis-sions. Widespread pollution from the biomass burnings in Southeast Asia was simulated using aCO tracer driven by a 3D global chemical transport model. This simulation indicates that tropical deep convections connected to rapid advection by the subtropical jet play a significant role in dis-persing biomass-burning emissions from Southeast Asia on a global scale.     

Upper limb kinematical analysis of an elite weight lifter in the squat snatch

The kinematical parameters such as translational acceleration and angular acceleration in the upper limb of a weightlifter may change regularly during different phases of squat snatch. This study aims to make this question clear. At first, the joint coordinate system (JCS) of human upper limb based on the anatomical landmarks is defined. Then a novel method for calculating the kinematical parameters was brought forward, which was based on analyzing the relative position of the JCS to world coordinate system during an instantaneous situation and the relationship among each JCS at different times during squat snatch. Motion capture system is used to gather the data of the upper limb in an elite weightlifter during squat snatch (the mass of the barbell is 20 kg) and the method mentioned before is applied to analyze the data. Finally, the law of the change of kinematical parameters in each phase of squat snatch is found.     

Daily rhythms in activity and mRNA abundance of enzymes involved in glucose and lipid metabolism in liver of rainbow trout,Oncorhynchus mykiss. Influence of light and food availability

ABSTRACT

We have investigated the magnitude of diurnal variation in back squat and bench press performance using the MuscleLab force velocity transducer. Thirty resistance-trained males (mean ± SD: age 21.7 ± 1.4 years; body mass 80.5 ± 4.5 kg; height 1.79 ± 0.06 m) underwent two sessions at different times of day: morning (M, 07:30 h) and evening (E, 17:30 h). Each session included a period when rectal temperature (T_rec) was measured at rest, a 5-min standardized 150 W warm-up on a cycle ergometer, then defined programme of bench press (at 20, 40 and 60 kg) and back squat (at 30, 50 and 70 kg) exercises. A linear encoder was attached to an Olympic bar used for the exercises and average force (AF), peak velocity (PV) and time-to-peak velocity (tPV) were measured (MuscleLab software; MuscleLab Technology, Langesund, Norway) during the concentric phase of the movements. Values for T_rec at rest were higher in the evening compared to morning values (0.48°C, P < 0.0005). Daily variations were apparent for both bench press and back squat performance for AF (1.9 and 2.5%), PV (8.3 and 12.7%) and tPV (?16.6 and ?9.8%; where a negative number indicates a decrease in the variable from morning to evening). There was a main effect for load where AF and tPV increased and PV decreased from the lightest load to the heaviest for both bench press and back squat (47.1 and 80.2%; 31.7 and 57.7%; ?42.1 and ?73.9%; P < 0.0005 where a negative number indicates a decrease in the variable with increasing load). An interaction was found only for tPV, such that the tPV occurs earlier in the evening than the morning at the highest loads (60 and 70 kg) for both bench press and back squat, respectively (mean difference of 0.32 and 0.62 s). In summary, diurnal variation in back squat and bench press was shown; and the tPV in complex multi-joint movements occurs earlier during the concentric phase of exercise when back squat or bench press is performed in the evening compared to the morning. This difference can be detected using a low cost, portable and widely available commercial instrument and enables translation of past laboratory/tightly controlled experimental research in to main-stream coaching practice.     

Acoustic reflectometry for an in vitro model of a human upper airway using sinusoidal wave packets and the Ware–Aki algorithm

Acoustic reflectometry is often used for estimating the cross-sectional area of a cylindrical cavity when used in combination with an acoustic pulse. The objective of this research is to sweep a spectral bandwidth from 50 Hz to 10 kHz at steps of 50 Hz, with Gaussian sinusoidal wave packets, and to apply the Ware–Aki algorithm. In practice, not only it is difficult to generate a broad spectral bandwidth, but also robust methods are required to compensate for attenuation in the propagating wave and to eliminate a DC offset component generated in its impulse response. This paper looks at using numerical techniques to compute the impulse response and estimate the cross-sectional area as a function of an increment in the frequency response. Preliminary results show that both simulated and reconstructed cross-sectional areas for an in vitro model of a human upper airway may be estimated with an appropriate resolution, suggesting that this method is suitable for such applications.     

TRAINING LOAD,IMMUNE SYSTEM,UPPER RESPIRATORY SYMPTOMS AND PERFORMANCE IN WELL-TRAINED CYCLISTS THROUGHOUT A COMPETITIVE SEASON

This study aimed to evaluate the leukocyte subset counts, serum immunoglobulin A, performance and upper respiratory symptoms (URS), as well as their interrelationships, of well-trained cyclists for a 29-week training season using monitored loads. The season was divided into three phases: preparatory (nine weeks), first competitive phase (nine weeks) and second competitive phase (11 weeks). The sample consisted of eight well-trained cyclists, aged 18 ± 2 years. Immunological parameters and performance were evaluated during weeks 1 (baseline), 10 (early first competitive phase), 19 (early second competitive phase) and 29 (end of the second competitive phase). The training loads (volume x rating of perceived exertion) were monitored daily while the monitoring of URS was performed every 15 days using the WURSS-44 questionnaire. The data were analyzed using a one-way ANOVA and a Pearson correlation test with the significance level set at p ≤ 0.05. No significant differences were found for training load, leukocyte subset counts or serum immunoglobulin A among the three phases. However, serum immunoglobulin A was 50.9% below the control group values. URS were significantly higher during the preparatory period, and there were significant correlations between URS and training load (strain) in the preparatory period (r = 0.72, p = 0.032) and second competitive phase (r = 0.73, p = 0.036). In conclusion, indicators of training load without a significant change throughout the season did not significantly affect immune parameters measured; however, the increase of strain can cause an increase of upper respiratory symptoms throughout the season, but without loss of performance.