50 resultados para ultra-wideband
Resumo:
There are reports of the effect of endurance exercise on mucosal immune function and of the effect of short duration exercise on humoral immune function. However, little is known of the effect of endurance exercise on humoral immune function and the related risk of infection. This study examined the effects of an ultra-endurance running race on salivary immunoglobulin-A (s-IgA), serum IgA, leukocyte subset concentrations and the incidence of upper respiratory tract infections (URTI).
Thirteen male and 4 female competitors provided saliva samples and blood before and at several times after the running race. Self-reported symptoms of URTI were also recorded for 2 weeks before and 2 weeks after the race.
Salivary IgA secretion rate (P=0.005) and ratio to osmolality (P=0.006) were lower immediately postrace and decreased further for at least 2 more h. s-IgA secretion rate had not returned to normal the next morning (P=0.009). Serum IgA concentration was lower post- than prerace (P=0.003) and was even lower the next morning (P<0.001). Leukocyte con centration was elevated postrace (P<0.001), mainly because of an increase in neutrophils (P<0.001) and both remained high the morning after the race (P<0.001). Lymphocyte concentration decreased postrace (P<0.001) and was still depressed the next morning (P=0.032). The incidence of symptoms of URTI was the same in the two 2-week periods before and after the race.
These findings support the hypotheses that an ultra-endurance run may adversely affect mucosal immunity and cause significant changes in the concentration of leukocyte subsets.
Resumo:
An operational transconductance amplifier (OTA) using dynamic threshold MOS (DTMOS) and hybrid compensation technique is presented in this paper. The proposed topology is based on a bulk and gate driven input differential pair. Two separate capacitors are employed for the OTA compensation where one of them is used in a signal path and the other one in a non-signal path. The circuit is designed in the 0.18μm CMOS TSMC technology. The proposed design technique shows remarkable enhancement in unity gain-bandwidth and also in DC gain compared to the bulk driven input differential pair OTAs. The Hspice simulation results show that the amplifier has a 92dB open-loop DC gain and a unity gain-bandwidth of 135kHz while operating at 0.4V supply voltage. The total power consumption is as low as 386nW which makes it suitable for low-power bio-medical and bio-implantable applications.
Resumo:
Objective
The neighbourhood built environment may affect walking behaviour of elders. However, such effects remain underexplored, especially in an Asian context. We examined associations of perceived environmental attributes with overall and neighbourhood-specific walking for transport in a sample of Chinese elders residing in Hong Kong, an ultra-dense Chinese metropolis.
Design
Cross-sectional observational study using a two-stage stratified sampling strategy.
Setting
Hong Kong, China.
Subjects
Chinese-speaking elders (n 484), with no cognitive impairment and able to walk without assistance, residing in thirty-two selected communities stratified by socio-economic status and walkability, were interviewer-administered validated measures of perceived neighbourhood environment and walking for transport.
Results
Much higher levels of transport-related walking (mean 569 (sd 452) min/week) than found in Western samples were reported. The degree of perceived access to shops, crowdedness, presence of sitting facilities and easy access of residential entrance were independently positively related to both frequency of overall and within-neighbourhood walking for transportation. Infrastructure for walking and access to public transport were predictive of higher frequency of transport-related walking irrespective of location, while the perceived degree of land-use mix was predictive of higher levels of within-neighbourhood walking.
Conclusions
The provision of easy access to shops, residential entrances and sitting facilities in the neighbourhood may promote overall transport-related walking, while a good public transport network and pedestrian infrastructure linking destination-poor with destination-rich locations may compensate for the detrimental effects of living in less walkable neighbourhoods. Governmental investment in these micro- and macro-environmental features would help the promotion of an active lifestyle in elders.
