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1.
乌药活性组分LEF的化学成分及抗风湿作用   总被引:4,自引:0,他引:4  
从乌药〔Linderaaggregata(Sims)Kosterm.〕根的镇痛、抗炎活性组分(LEF)中分离得到6个缩合鞣质类化合物,鉴定出其中4个,分别为表儿茶素()epicatechin、表儿茶素()epigallocatechin、procyanidinB2及trimericproanthocyanidin(cinnamtanninsB1),另得到一个黄酮甙,鉴定为橙皮甙hesperidin,以上化合物均为首次从乌药中分离得到。药理实验表明,乌药LEF组分对大鼠佐剂性关节炎有明显的治疗作用,对风寒湿痹证模型大鼠炎性肿胀有明显的对抗效应,能够明显降低模型动物炎性组织渗出液中前列腺素(PGE2)含量,具有良好的抗风湿应用前景  相似文献   

2.
Previous studies of autonomic nervous system responses before and after eating when controlling patient conditions and room temperature have provided inconsistent results. We hypothesized that several physiological parameters reflecting autonomic activity are affected by outdoor temperature before and after a meal. We measured the following physiological variables before and after a fixed meal in 53 healthy Japanese women: skin temperature, systolic and diastolic blood pressure, salivary amylase, blood glucose, heart rate, and heart rate variability. We assessed satiety before and after lunch using a visual analog scale (100 mm). We recorded outdoor temperature, atmospheric pressure, and relative humidity. Skin temperature rose significantly 1 h after eating (greater in cold weather) (P?=?0.008). Cold weather markedly influenced changes in diastolic blood pressure before (P?=?0.017) and after lunch (P?=?0.013). Fasting salivary amylase activity increased significantly in cold weather but fell significantly after lunch (significantly greater in cold weather) (P?=?0.007). Salivary amylase was significantly associated with cold weather, low atmospheric pressure, and low relative humidity 30 min after lunch (P?P?=?0.001). The decreased low frequency (LF)/high frequency (HF) ratio, increased Δ LF/HF ratio, and increased Δ salivary amylase activity imply that cold outdoor temperature is associated with dominant parasympathetic activity after lunch. Our results clarify the relationship between environmental factors, food intake, and autonomic system and physiological variables, which helps our understanding of homeostasis and metabolism.  相似文献   

3.
The frequency of bronchial asthma in Nairobi is related to meteorological parameters such as relative humidity, rainfall, dew point temperature, hours of sunshine and dry bulb temperature. Two seasons were taken for study: one cold season (May–August 1975) and one relatively warm season (December 1975–March 1976). It was found that significant correlations occurred at a lag of 2 or 3 days, but not at a lag of 4 or 5 days. Cold and wet weather during the cold season and heat of the day and dryness of the atmosphere during the warm season aggravate asthma in Nairobi.. The frequency of asthmatic attacks is about the same during the two seasons, but the intensity of suffering of a greater majority of patients is more in cold and wet weather than in warm and dry weather. 20–25% of the patients do not feel any relationship between weather and their asthmatic troubles. Nearly twice as many patients suffer from cough with the production of sputum in the cold season than in the warm season. About three times as many patients suffer from bronchospasm in the cold season than in the warm season. Severe asthmatic attacks occur almost equally in both the seasons.  相似文献   

4.
The effect of weather on social interactions has been explored through the analysis of a large mobile phone use dataset. Time spent on phone calls, numbers of connected social ties, and tie strength were used as proxies for social interactions; while weather conditions were characterized in terms of temperature, relative humidity, air pressure, and wind speed. Our results are based on the analysis of a full calendar year of data for 22,696 mobile phone users (53.2 million call logs) in Lisbon, Portugal. The results suggest that different weather parameters have correlations to the level and character of social interactions. We found that although weather did not show much influence upon people''s average call duration, the likelihood of longer calls was found to increase during periods of colder weather. During periods of weather that were generally considered to be uncomfortable (i.e., very cold/warm, very low/high air pressure, and windy), people were found to be more likely to communicate with fewer social ties. Despite this tendency, we found that people are more likely to maintain their connections with those they have strong ties with much more than those of weak ties. This study sheds new light on the influence of weather conditions on social relationships and how mobile phone data can be used to investigate the influence of environmental factors on social dynamics.  相似文献   

5.
The study and interpretation of temporal variability in mortality requires the consideration of both exogenous and endogenous influences as underlying factors. In the present paper the relative contribution of fluctuations in daily weather was investigated using the unbiased techniques of lagged cross-correlation and spectral analyses. The study focused on patterns of daily mortality in Kyoto, Japan. Studied herein were total mortality of all ages less accidental, ischemic heart (IHD), cerebrovascular (CVD), cardiovascular (IHD + CVD), cancer and among elderly (over 70 years of age) deaths. The meteorological factors were mean, maximum and minimum daily temperature, mean barometric pressure, mean relative humidity, and mean and maximum wind speed. It was found that after extreme weather conditions, such as heat waves (with mean air temperature in excess of 30°C) or the intrusion of cold waves (with mean air temperature below 0°C), mortality increased to about three times the daily average with a lag effect of usually one—three days and up to one week. Over the year, however, weather fluctuations were found to account statistically for no more than 10% of the overall annual variability in mortality. Importantly, the short-term upswings in mortality were usually accompanied by noticeable drops in the number of deaths on the subsequent days suggesting a triggering effect of external factors. The most weather-sensitive mortality group was people over 70 years of age.  相似文献   

6.
Analysis of the time of onset of chest pain in 2254 patients with a myocardial infarction admitted to a coronary care unit in Leicester during a 10-year period shows an association with temperature and humidity. During both the most cold and humid times of the year, the relationship is a strong one. A generalized linear model with a log link was used to fit the data and the backward elimination selection procedure suggested a humid, cold day might help to trigger the occurrence of myocardial infarction. In addition, cold weather was found to have a stronger effect on the male population while those men aged between 50 and 70 years were more sensitive to the effect of high humidity.  相似文献   

7.
Climate change is one of the most important concerns for public health that affects communities and is a threat to human health. Few cross-sectional studies investigated the effects of extreme temperature as a risk factor on the cardiovascular system and the Out-of-Hospital Cardiac Arrests (OHCA).The current study aims to investigate the association between climate variables (cold and hot weathers, humidity, atmospheric pressures) with Out-of-Hospital Cardiac Arrests in Rasht, Iran.This is an ecological time-series study, which investigated 392 patients with OHCA that were hospitalized in Dr. Heshmat Medical center of Rasht city in a 3-years period. Data on meteorological variables were obtained from the General Meteorological Department of Guilan Province. Information regarding the number of cardiac arrest admissions was obtained from the sole specialized cardiac hospital of Rasht. Data were analyzed using R software.Hot weather decreases the number of cardiac attacks on the same day (lag 0), while the cold weather (relative risk (RR) = 1.408; confidence interval (CI): 1.014–1.955) increases the number of OHCA cases and unsuccessful cardiopulmonary resuscitation (CPRs). Low humidity (RR = 1.76; CI: 1.006–3.79) is associated with increased unsuccessful CPRs. High atmospheric pressures (RR = 1.166; CI: 1.001 to 1.787) are also associated with an increased number of cardiac arrest admissions. For women, men, and those aged >65 years of old, exposure with severe cold (RR = 1.335; CI: 1.014–1.758) and hot weathers, respectively, increases and decreases the number of cardiac arrest admissions.Cold weather has immediate impacts on the incidence of OHCA cases and unsuccessful CPRs. Decreasing humidity also increases the number of and decreases the success rate of CPRs. Increasing the awareness of patients with cardiovascular diseases (CVDs as well as improving the preparedness of emergency care teams can decrease the impacts of climate variables.  相似文献   

8.
THE EPIDEMIOLOGY OF PHYTOPHTHORA INFESTANS   总被引:5,自引:0,他引:5  
Temperature and relative humidity of air within and above potato crops were recorded throughout the growing seasons of 1951-8, with wet- and dry-bulb mercury-in-steel thermographs. Diurnal periodicity curves of successive weeks showed that conditions within the crop changed, relative to those above, as the crop grew. When much bare ground was exposed, the air within the crop was warmer and less humid at midday than at 4 ft. above ground, particularly in dry and sunny weather. The growth of the foliage and the amount of sunshine and rain determined how quickly this pattern was replaced by one with smaller temperature differences and crop humidity slightly in excess of that above it, at all times of day. Rain on crops with dense foliage almost completely eliminated temperature differences and gave relative humidities over 90% that persisted in the crop for a larger proportion of each day than in the screen. Finally, as the disease defoliated the crop and again exposed the soil, the relationship partly reverted to that early in the season.
Above the crops, curves of the number of hours per day with relative humidity not less than 90%, rose and fell with the passing of wet spells. At first this was also true within crops, but when foliage was dense the rise in relative humidity after rain often persisted through intervals of dry weather. Such conditions usually preceded the appearance of potato blight in epidemic proportions by 1–3 weeks. It is difficult to account for the regularity of blight outbreaks by seasonal climatic changes, and although many factors are probably involved, changes in ecoclimate seem important. When knowledge about the response of Phytophthora infestans is related to the meteorological observations and to the dates of blight outbreak, the growth of potato crops seems often to be self-destructive, because it progressively modifies the immediate environment to favour the spread of the crop's most destructive pathogen.  相似文献   

9.
甘肃兴隆山马麝呼吸系统疾病流行病初步调查   总被引:6,自引:0,他引:6  
对甘肃省兴隆山国家级自然保护区马麝人工驯养场马麝呼吸系统疾病进行了自然概况及饲养管理情况调查、既往流行病学统计、临床症状和病理剖检变化观察、预防和治疗情况调查。结果表明,马麝呼吸系统疾病的流行与当地的温度和湿度(尤其是湿度)密切相关,年平均湿度较高的月份该病的发病率明显高于年平均湿度较低的月份;天气骤冷、阴雨连绵等应激因子可促使本病的发生。  相似文献   

10.
The indoor aeromycota in several rooms of each of 15 residences in Kitchener-Waterloo, Ontario, Canada was studied from December 1991 to September 1993. There were significant differences in airborne spore concentrations among the types of rooms investigated. Numbers of airborne propagules were highest in the living rooms, followed by family rooms, kitchens, bathrooms and bedrooms. The highest fungal diversity was found in kitchens. Generally, presence of dampness and of carpets led to increased numbers of airborne spores. Forced air heating systems, humidifiers, air filters and air conditioners reduced concentrations of airborne fungi. Patients with respiratory allergies and known sensitivity to moulds reported allergic symptoms significantly less severe than average in residences with air conditioners, air filters, humidifiers and forced air heating systems. In damp residences, their symptoms were significantly more severe than the average.Abbreviations CFU colony forming unit - RH relative humidity  相似文献   

11.
Using the guinea pig as a model host, we show that aerosol spread of influenza virus is dependent upon both ambient relative humidity and temperature. Twenty experiments performed at relative humidities from 20% to 80% and 5 degrees C, 20 degrees C, or 30 degrees C indicated that both cold and dry conditions favor transmission. The relationship between transmission via aerosols and relative humidity at 20 degrees C is similar to that previously reported for the stability of influenza viruses (except at high relative humidity, 80%), implying that the effects of humidity act largely at the level of the virus particle. For infected guinea pigs housed at 5 degrees C, the duration of peak shedding was approximately 40 h longer than that of animals housed at 20 degrees C; this increased shedding likely accounts for the enhanced transmission seen at 5 degrees C. To investigate the mechanism permitting prolonged viral growth, expression levels in the upper respiratory tract of several innate immune mediators were determined. Innate responses proved to be comparable between animals housed at 5 degrees C and 20 degrees C, suggesting that cold temperature (5 degrees C) does not impair the innate immune response in this system. Although the seasonal epidemiology of influenza is well characterized, the underlying reasons for predominant wintertime spread are not clear. We provide direct, experimental evidence to support the role of weather conditions in the dynamics of influenza and thereby address a long-standing question fundamental to the understanding of influenza epidemiology and evolution.  相似文献   

12.
J. H. Evans 《Hydrobiologia》1960,15(4):384-384
Summary There appears to be an association between the relative humidity of the atmosphere and the vertical distribution of certain diatoms in the uppermost few millimeters of leaf litter at pond margins. Cells tend to accumulate at the surface when the relative humidity exceeds 70% and below the surface at lower relative humidities.There are indications also that the vertical distribution of flagellates might be associated with relative humidity.Diatoms and other algae have been grown on a variety of media, particularly damp, sterile mud. Culture experiments indicate that the critical moisture content, below which cells of two diatoms, Pinnularia biceps f. minutissima and Navicula cryptocephala, tend to lose their viability, is in the region of 50% (of the wet weight).For these two species of diatoms, it would appear that cells which accumulate fat are more likely to survive drying than those which do not. The protoplast of certain cells of these two diatoms appeared to develop a fatty peripheral layer during drying. Pinnularia biceps f. minutissima remained viable after a further year of drying.  相似文献   

13.
The concentration of pollen in the air within diploid open-pollinated sugar-beet seed crops at Broom's Barn Experimental Station increased between 05.00 and 09.00 G.M.T. as relative humidity became less than 90%, was greatest between 09.00 and 11.00, when relative humidity was c. 75%, and gradually decreased towards evening. The average pollen concentration during 24 h periods ranged from 170 to 12400/m3 being greatest on fine, windy, dry days after periods of cooler weather. Rain during the morning washed pollen out of the air and damaged developing anthers, but rain in the late afternoon following a sunny morning seemed hardly to affect the pollen catch, while rain at night sometimes caused an immediate temporary increase in pollen concentration. Most pollen was released between 27 June and 31 July in all years (1965-7); more in the first than in the second half of July. 1965 was cool and damp, 1967 warm and dry, 1966 warm and dry early, and cool and wet late. The total pollen catch in 1965 was 83% and in 1966 31% of that in 1967 but the percentage germination of seed harvested in the 3 years was similar. The total pollen catch on a trap 230 m east of the 1965 crop was c. 1% of the catch within the crop on days with gusty westerly winds and the catch on a trap c. 46 cm above the 1966 crop averaged 78.6% of that at the level of most flowers.  相似文献   

14.
This research assesses the potential impact of weekly weather variability on the incidence of cryptosporidiosis disease using time series zero-inflated Poisson (ZIP) and classification and regression tree (CART) models. Data on weather variables, notified cryptosporidiosis cases and population size in Brisbane were supplied by the Australian Bureau of Meteorology, Queensland Department of Health, and Australian Bureau of Statistics, respectively. Both time series ZIP and CART models show a clear association between weather variables (maximum temperature, relative humidity, rainfall and wind speed) and cryptosporidiosis disease. The time series CART models indicated that, when weekly maximum temperature exceeded 31°C and relative humidity was less than 63%, the relative risk of cryptosporidiosis rose by 13.64 (expected morbidity: 39.4; 95% confidence interval: 30.9–47.9). These findings may have applications as a decision support tool in planning disease control and risk-management programs for cryptosporidiosis disease.  相似文献   

15.
The purpose of this research was to explore the latent dimensions that underlie people’s use of adjectives that can describe weather and climate conditions. A sample of 1,011 university undergraduate students residing the southeastern United States evaluated the weather and climate of that region using 143 English language adjectives. Data were collected over a two-year period during various weather and seasonally related climatic conditions. Polychoric correlations among the adjective ratings were calculated; the matrix of correlations was factor analyzed. Twelve underlying factors related to weather and climate perceptions were observed: 1. threatening, severe, violent, 2. dismal, drab, dark, 3. cold and wintry, 4. hot and summery, 5. tranquil and pleasant, 6. stormy and wet, 7. bright and clear, 8. blowing and blustery, 9. damp and moist, 10. cloudy and cool, 11. predictable and unchanging, and 12. hazy and dusty. A second-order factor analysis revealed two factors pertaining to weather valence: 1. bad or extreme and 2. good or routine conditions. The study results were noteworthy in revealing some of the basic linguistic dimensions along which people perceive and experience weather and climate at the current time in the southeastern United States. The study also represents the use of a new technique for biometeorologists to use in assessing climate perceptions in culturally and climatically diverse regions.  相似文献   

16.
This study analyzes the effect of weather variables, such as solar radiation, indoor and outdoor air temperature, relative humidity and time spent outdoor, on the behavior of 2-year-old children and their affects across different seasons: winter, spring and summer. Participants were a group of 61 children (33 males and 28 females) attending four day-care centers in Florence (Central Italy). Mean age of children at the beginning of the study was 24.1 months (SD?=?3.6). We used multilevel linear analyses to account for the hierarchical structure of our data. The study analyzed the following behavioral variables: Activity Level, Attentional Focusing, Frustration, and Aggression. Results showed a different impact of some weather variables on children’s behavior across seasons, indicating that the weather variable that affects children’s behavior is usually the one that shows extreme values during the studied seasons, such as air temperature and relative humidity in winter and summer. Studying children and their reactions to weather conditions could have potentially wide-reaching implications for parenting and teaching practices, as well as for researchers studying social relationships development.  相似文献   

17.
Echolocating bats are regularly studied to investigate auditory‐guided behaviors and as important bioindicators. Bioacoustic monitoring methods based on echolocation calls are increasingly used for risk assessment and to ultimately inform conservation strategies for bats. As echolocation calls transmit through the air at the speed of sound, they undergo changes due to atmospheric and geometric attenuation. Both the speed of sound and atmospheric attenuation, however, are variable and determined by weather conditions, particularly temperature and relative humidity. Changing weather conditions thus cause variation in analyzed call parameters, limiting our ability to detect, and correctly analyze bat calls. Here, I use real‐world weather data to exemplify the effect of varying weather conditions on the acoustic properties of air. I then present atmospheric attenuation and speed of sound for the global range of weather conditions and bat call frequencies to show their relative effects. Atmospheric attenuation is a nonlinear function of call frequency, temperature, relative humidity, and atmospheric pressure. While atmospheric attenuation is strongly positively correlated with call frequency, it is also significantly influenced by temperature and relative humidity in a complex nonlinear fashion. Variable weather conditions thus result in variable and unknown effects on the recorded call, affecting estimates of call frequency and intensity, particularly for high frequencies. Weather‐induced variation in speed of sound reaches up to about ±3%, but is generally much smaller and only relevant for acoustic localization methods of bats. The frequency‐ and weather‐dependent variation in atmospheric attenuation has a threefold effect on bioacoustic monitoring of bats: It limits our capability (1) to monitor bats equally across time, space, and species, (2) to correctly measure frequency parameters of bat echolocation calls, particularly for high frequencies, and (3) to correctly identify bat species in species‐rich assemblies or for sympatric species with similar call designs.  相似文献   

18.
山地小气候模拟研究进展   总被引:9,自引:0,他引:9       下载免费PDF全文
山地气候是最为复杂的气候类型之一,加上观测点少,气象资料比较缺乏,研究的难度很大,采用模型模拟的方法对山地气候进行研究是气象和生态学的交叉领域,得到气象和生态学者的广泛重视.目前,山地小气候模型模拟已得到很大的发展,作者从温度、降水、湿度、太阳辐射和风场5个方面综述了国内外在这方面的研究进展1)温度场的模拟主要是以分离-综合法改进后的多元回归法为主;2)降水模拟的方法主要有地形因子相关法(又可分为单要素、双要素、三要素和多要素)和趋势面法;3)关于湿度,一般气象站只观测水汽压和相对湿度,但一般的生态系统模型却是以水气压饱和差来表征湿度的,用湿度-辐射循环法模拟;4)太阳辐射的模拟很复杂,主要以直接辐射、散射辐射、反射辐射和总辐射分别来模拟;5)风场主要模拟方法有诊断方法和预报方法.以上对山地小气候的模型模拟总的特点为区域性强、经验性大、普适性(理论性)差.同时,我们根据实际研究工作,展望了未来山地气候中小尺度模拟研究的两个侧重点1) 今后要综合、动态地模拟山地小气候系统,用现代理论尤其是非线性理论来研究山地气候,以加强理论方面的研究;2) 加强对先进技术(例如GIS、RS等)的吸收利用.  相似文献   

19.
Summary A review is given of the adaptations of arthropods to life on land. The terrestrial Arthropoda are divided ecologically into two main groups. The first of these includes woodlice, centipedes, miilipedes and their allies which lose water rapidly in dry air and consequently are restricted to damp, dark habitats which they leave only at night when the temperature falls and the relative humidity of the air rises. The second group includes most insects and Arachnida: these are comparatively independent of moist surroundings because their integument possesses an impervious layer of wax which prevents desiccation.  相似文献   

20.
Field observations of air and surface temperatures, relative humidity, solar radiation and wind were performed in the daytime hours of the warm season around a pond of 4 ha, located in Begin Park, in the city of Tel Aviv, Israel. Observations were carried out at screened meteorological stations on four randomly selected days, all associated with moderate heat stress. Two of them, one representing a warm and dry day, and other, representing a sultry day, are analyzed in detail. At the downwind side of the pond, lower temperatures, a higher relative humidity and a lower heat stress index were observed consistently when compared with stations located upwind of the pond. This effect is regarded here as the "lake effect". The fact that no significant change was noted in the water vapor pressure during most of the daytime hours indicates that the lake effect was related mainly to cooling rather than to moisture transport from the pond. A positive relationship was found between the lake effect and wind speed in both types of weather. The maximum effect of the wind's speed on the lake effect was observed at midday, at which time the temperature drop reached 1.6 degrees C, while the relative humidity rose by 6%. As a result, the heat stress index dropped by 0.8-1.1 degrees C. It is suggested that the temperature drop induced by the pond during the warmest hours of the day was mainly the result of a truncation of the sensible heat flux from the underlying surface when the air, which had previously passed over hot surfaces, swept over the relatively cool water. During the late afternoon and evening hours, when the water became warmer than the surrounding surfaces, latent heat cooling resulting from evaporation became the dominant source of the lake effect, and the lake effect resulted in increasing heat stress. It is concluded that even small bodies of water have a relieving effect on humans in the daytime hours, within the range of 40 m, under both dry and humid hot weather conditions.  相似文献   

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