نتایج جستجو برای: caffeine

تعداد نتایج: 11294  

Journal: :Clinical pharmacology and therapeutics 2007
J V Rétey M Adam R Khatami U F O Luhmann H H Jung W Berger H-P Landolt

Caffeine is the most widely used stimulant in Western countries. Some people voluntarily reduce caffeine consumption because it impairs the quality of their sleep. Studies in mice revealed that the disruption of sleep after caffeine is mediated by blockade of adenosine A2A receptors. Here we show in humans that (1) habitual caffeine consumption is associated with reduced sleep quality in self-r...

Journal: :Marine pollution bulletin 2010
Karen L Knee Richard Gossett Alexandria B Boehm Adina Paytan

Caffeine has been associated with wastewater pollution in temperate and subtropical locations, but environmental caffeine concentrations in tropical locations have not been reported. The objectives of this study were to measure caffeine and agricultural pesticide (carbaryl, metalaxyl, and metribuzin) concentrations in environmental waters on the tropical north shore of Kauai (Hawaii, USA) and a...

2013
Wang Xu Tae-Hyeong Kim Duanting Zhai Jun Cheng Er Liyun Zhang Anup Atul Kale Bikram Keshari Agrawalla Yoon-Kyoung Cho Young-Tae Chang

Caffeine has attracted abundant attention due to its extensive existence in beverages and medicines. However, to detect it sensitively and conveniently remains a challenge, especially in resource-limited regions. Here we report a novel aqueous phase fluorescent caffeine sensor named Caffeine Orange which exhibits 250-fold fluorescence enhancement upon caffeine activation and high selectivity. N...

Journal: :Sports medicine 2001
T E Graham

Caffeine is a common substance in the diets of most athletes and it is now appearing in many new products, including energy drinks, sport gels, alcoholic beverages and diet aids. It can be a powerful ergogenic aid at levels that are considerably lower than the acceptable limit of the International Olympic Committee and could be beneficial in training and in competition. Caffeine does not improv...

Journal: :Journal of psychopharmacology 2005
Andrew Smith David Sutherland Gary Christopher

Evidence for behavioural effects of caffeine is well documented in the literature. It is associated with increased subjective alertness, improved reaction time and enhanced encoding of new information. These effects are most prominent in low arousal situations. However, there is an ongoing debate as to whether such changes are in fact improvements or merely a reversal of the negative effects of...

2008

Objective To examine the association ofmaternal caffeine intake with fetal growth restriction. Design Prospective longitudinal observational study. Setting Two large UK hospital maternity units. Participants 2635 low risk pregnant women recruited between 8-12 weeks of pregnancy. Investigations Quantification of total caffeine intake from 4weeksbeforeconceptionand throughoutpregnancywas undertak...

Journal: :European journal of pharmacology 2011
Marcelo T Marin Roberta Zancheta Ana H Paro Ana P M Possi Fábio C Cruz Cleopatra S Planeta

Caffeine is the psychostimulant drug most consumed in the world. This drug is present in food, beverages and medicines marketed for individuals of all ages. In spite of this, caffeine effects on adolescents are poorly understood. The aim of this study was to evaluate the differences on caffeine-induced locomotor stimulant or depressant effects in adolescent and adult rats. Adolescent (37-40 day...

2006
Shishir K. Das Ching C. Lau Arthur B. Pardee Sidney Farber

Greatly enhanced lethality for Syrian hamster cells (baby hamster kidney cells and polyomavirus-transformed derivative of baby hamster kidney cells) that had been treated with alkylating agents or ultraviolet light is produced by caffeine. Thus, nitrogen mustard [methylbis(/?-chloroethyl)amine] (HN2) at 0.5 /¿Mdecreased cell viability by only a few percent in the absence of caffeine. The addit...

Journal: :Thrombosis and haemostasis 2012
Cathérine Gebhard Erik W Holy Giovanni G Camici Alexander Akhmedov Simon F Stämpfli Barbara E Stähli Bettina von Rickenbach Alexander Breitenstein Helen Greutert Zhihong Yang Thomas F Lüscher Felix C Tanner

Tissue factor (TF) is the key activator of coagulation and is involved in acute coronary syndromes. Caffeine is often reported to increase cardiovascular risk; however, its effect on cardiovascular morbidity and mortality is controversial. Hence, this study was designed to investigate the impact of caffeine on endothelial TF expression in vitro. Caffeine concentration-dependently enhanced TF pr...

Journal: :Social cognitive and affective neuroscience 2012
Jessica E Smith Andrew D Lawrence Ana Diukova Richard G Wise Peter J Rogers

Caffeine, an adenosine A₁ and A(2A) receptor antagonist, is the most popular psychostimulant drug in the world, but it is also anxiogenic. The neural correlates of caffeine-induced anxiety are currently unknown. This study investigated the effects of caffeine on brain regions implicated in social threat processing and anxiety. Participants were 14 healthy male non/infrequent caffeine consumers....

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