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1.
Participants in a taste test study were randomly assigned to 1 of 3 groups: warning label (e.g., "In this product, 90% of the calories come from fat. Warning: The U.S. Surgeon General has determined that eating high fat food increases your risk of heart disease." ), information label (e.g., "In this product, 90% of the calories come from fat." ), and no label. Participants rated how much they wanted to taste full-, reduced-, and no-fat cream cheeses, and they chose I type to eat. People in the warning- and no-label groups wanted to taste the full-fat product more than those in the information-label group. People in the warning- and information-label groups were less likely to eat the full-fat product than those in the no-label group. People reacted to the warning label but avoided the full-fat product. For products with credible and familiar risks, information labels may be more effective than warning labels because they don't arouse reactance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

2.
The effect of acetylcholine on the neurointermediate lobe beta-endorphin secretion was studied in the neonatal and in the adult rat in vitro. Acetylcholine stimulated beta-endorphin secretion from the 2-day- and 5-day-old neurointermediate lobe, the effect was dose dependent and more pronounced in the presence of the cholinesterase inhibitor eserine. The 10-day-, the 21-day-old and the adult rat neurointermediate lobes did not respond to acetylcholine, even in the presence of eserine. Basal beta-endorphin secretion was elevated by the D2 receptor antagonist sulpiride, but acetylcholine was without effect in the 10-day-old and in the adult neurointermediate lobe even after dopamine receptor blockade. The beta-endorphin stimulatory response to acetylcholine was diminished by the M1 muscarinic receptor antagonist pirenzepine and blocked by the M3 > M1 antagonist 4-diamino-phenyl-piperidine (4-DAMP). The selective M2 antagonist methoctramine and nicotine had no effect. These data indicate that the neurointermediate lobe beta-endorphin secretion is under special muscarinic cholinergic regulation for a relatively short time after birth. The disappearance of this stimulatory cholinergic effect in later life might be due to changes in the intracellular secretory machinery in the IL and/or to the uncoupling of the cholinergic receptors from the intracellular signal transduction system(s) responsible for the stimulated secretion in the rat melanotrope cells.  相似文献   

3.
The aim of this study was to determine whether adenosine receptor blockade before ischemia would enhance the degree of stunning and induce a sustained decrease in glucose uptake after reperfusion. METHODS: Stunning was induced in 14 anesthetized swine by partially occluding the left anterior descending artery (LAD) for 20 min (> 80% flow reduction). Seven animals were pretreated with the nonspecific adenosine receptor blocker 8-phenyltheophylline (8-PT; 5 mg/kg), which decreased reactive hyperemia by an average of 38%. Myocardial glucose uptake was assessed 1 hr following reperfusion with PET and the glucose analog 18F-fluorodeoxyglucose (FDG). RESULTS: Before ischemia, systolic shortening in the LAD region was 15% +/- 6% in the control group and 16% +/- 4% in the 8-PT group and in both groups was reduced to - 1% +/- 2% during ischemia. After reperfusion, systolic shortening was 7% +/- 3% in the control group and 2% +/- 3% in the 8-PT group (p < 0.05). Myocardial oxygen consumption before ischemia was 4.58 +/- 3.03 micromol/min/g in the control group and 4.44 +/- 1.83 micromol/min/g in the 8-PT group (ns) and neither were different after reperfusion. In the postischemic LAD region, myocardial glucose uptake was 0.18 +/- 0.15 micromol/min/g in the control group and was similar to that of the 8-PT group (0.17 +/- 0.08 micromol/min/g; ns). CONCLUSION: The nonspecific adenosine blocker 8-PT enhanced the degree of stunning when given before ischemia but did not induce a sustained effect on myocardial glucose uptake after reperfusion.  相似文献   

4.
In most of the long history of the study of absolute identification—since Miller's (1956) seminal article—a severe limit on performance has been observed, and this limit has resisted improvement even by extensive practice. In a startling result, Rouder, Morey, Cowan, and Pfaltz (2004) found substantially improved performance with practice in the absolute identification of line lengths, albeit for only 3 participants and in a somewhat atypical paradigm. We investigated the limits of this effect and found that it also occurs in more typical paradigms, is not limited to a few virtuoso participants or due to relative judgment strategies, and generalizes to some (e.g., line inclination and tone frequency) but not other (e.g., tone loudness) dimensions. We also observed, apart from differences between dimensions, 2 unusual aspects of improvement with practice: (a) a positive correlation between initial performance and the effect of practice and (b) a large reduction in a characteristic trial-to-trial decision bias with practice. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   

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Acute toxic effects of fragrance products   总被引:1,自引:0,他引:1  
To estimate the prevalence of urinary stone disease in Koreans, and to determine the inter-relationships between urinary stone disease and various epidemiological factors, 1,521 controls and 1,177 cases with urinary stones were evaluated. Of special interest in this study were: 1) proportion of past urinary stone history among controls; 1.9% 2) the point prevalence rate of urinary stones among controls; 0.2% 3) the recurrence rate of urinary stones (the proportion of past history of urinary stone) among cases; 56.8% 4) high incidences (76.3%) in the thirties to the fifties among cases 5) the risk factors for urolithogenesis; obesity [higher than 25 of BMI (body mass index, weight/height2)], more than 10 year-experience as a production worker, past stone history, familial stone history, low physical activity (< 2,000 Kcal/day), and low intake of fruit. However, the well-known risk factors for urinary stones; over intake of meat or fish and milk or dairy products, perspiration, amount and kind of drinking water, and stress unexpectedly were not significantly different between the controls and the cases.  相似文献   

8.
An operant delayed-matching task was used to assess the role of proactive interference (PI) effects on short-term memory capacity of rats. Task performance was analyzed in terms of the influence of the sample positions and response choices on previous trials. PI was predominantly attributable to the influence of the immediately previous trial but not preceding trials and was abolished by increasing the intertrial intervals from 5 to 15 sec. Nicotine induced a decline in choice accuracy only on trials in which the previous response had been to the side opposite the current sample and correct response, suggesting an increased susceptibility to PI. Physostigmine induced a mild, relatively nonspecific decline in response accuracy. Clonidine induced delay-dependent impairments irrespective of responses on previous trials. None of these drugs enhanced choice accuracy at any dose tested. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

9.
The effects of the oral administration of 100 or 200 mg of heparan sulphate or placebo over time were assessed in nine healthy volunteers. Blood samples were collected at 1, 2, 4, 6, 8 and 12 hours after administration to assay prothrombin activity, partially activated thromboplastin time, and the activation to tPA and PAI-1. A significant increase (P < 0.001) of tPA activity and a reduced inhibition of fibrinolytic systems by PAI-1 were observed. These effects, which were clearly dose-dependent, appeared 2 hours after administration and persisted for 6-8 hours. On the contrary, no changes were recorded in coagulative tests at the doses used.  相似文献   

10.
Monte Carlo simulations of transmitter diffusion and its interactions with postsynaptic receptors have been used to study properties of quantal responses at central synapses. Fast synaptic responses characteristic of those recorded at glycinergic junctions on the teleost Mauthner cell (time to peak approximately 0.3-0.4 ms and decay time constant approximately 3-6 ms) served as the initial reference, and smaller contacts with fewer postsynaptic receptors were also modeled. Consistent with experimental findings, diffusion, simulated using a random walk algorithm and assuming a diffusion coefficient of 0.5-1.0 x 10(-5) cm2 s(-1), was sufficiently fast to account for transmitter removal from the synaptic cleft. Transmitter-receptor interactions were modeled as a two-step binding process, with the double-bound state having opened and closed conformations. Addition of a third binding step only slightly decreased response amplitude but significantly slowed both its rising and decay phases. The model allowed us to assess the sources of response variability and the likelihood of postsynaptic saturation as functions of multiple kinetic and spatial parameters. The method of nonstationary fluctuation analysis, typically used to estimate the number of functional channels at a synapse and single channel current, proved unreliable, presumably because the receptors in the postsynaptic matrix are not uniformly exposed to the same profile of transmitter concentration. Thus, the time course of the probability of channel opening most likely varies among receptors. Finally, possible substrates for phenomena of synaptic plasticity, such as long-term potentiation, were explored, including the diameter of the contact zone, defined by the region of pre- and postsynaptic apposition, the number and distribution of the receptors, and the degree of vesicle filling. Surprisingly, response amplitude is quite sensitive to the size of the receptor-free annulus surrounding the receptor cluster, such that expansion of the contact zone could produce an appreciable increase in quantal size, normally attributed to either the presence of more receptors or the release of more transmitter molecules.  相似文献   

11.
由于粉末注射成形(PowderInjectionMolding,PIM)产品具有很高的形状复杂度,故此工艺目前在工业界被广泛应用。其中铁系合金与不锈钢由于其性质优良,因此在近年来被广泛的使用在PIM工艺上。不过,由于粉末注射成形的粉末固体含量低,从生坯到最后的烧结工件,常伴随很大收缩(>12%)。使得此工艺之尺寸稳定性相对于其他工艺而言,是较差的。为了改善尺寸稳定性的问题,本研究针对升温速率、烧结温度以及相变态行为分别做探讨。试验结果显示,在全部步骤中,烧结过程有最大的收缩量,所以在此阶段中之尺寸稳定性最不容易控制,而较快的升温速率以及相变态的产生更造成此问题之恶化。本试验结果显示,使用较慢的升温速率,在烧结过程中避免相变态的发生,以及调整合金成分可大幅改善PIM件的尺寸稳定性。  相似文献   

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When directly transmitted infectious diseases are modeled assuming an everlasting induced immunity (and constant contact rate), there are well-established formulas to deal with, which is not true if we include the loss of induced immunity. In general, the immunity induced by the disease is everlasting. We propose a model considering the loss of immunity and present methods for the estimation of two epidemiological parameters: the force of infection and the basic reproduction ratio. We also analyze the effects of the loss of immunity on these parameters. Based on these results, we concluded that reinfection can play an important role in highly vaccinated populations.  相似文献   

14.
The present study evaluates the hematochemical and hemorheologic effects of mesoglycan, a preparation of natural glycosaminoglycans, administered by the intramuscular route to patients with a recent episode of cerebral ischemia. A total of twenty patients (13 males and 7 females), between the ages of 45 and 75, under observation for a cerebral ischemic episode occurring at least 2 months prior to enrollment, were treated with intramuscular mesoglycan (30 mg, twice daily), for 15 days. Blood samples were taken prior to and at the end of treatment to measure the investigated parameters. Following mesoglycan treatment we observed a statistically significant decrease in fibrinogen plasma concentration, total cholesterol and triglycerides, while HDL cholesterol was found to increase. In addition, erythrocytes filterability improved at the end of treatment. No changes were observed in coagulation parameters such as prothrombin time, partial thromboplastin time, or antithrombin III. The results of the present study demonstrate that a 15-days treatment of intramuscular mesoglycan in patients recovering from a cerebral ischemic episode produces significant changes in fibrinogen and lipid plasma levels with no apparent anticoagulant effect.  相似文献   

15.
Critical temperature (70 degrees C) of hot air exposure of children aged 4-5 was determined by physiological investigations. Determination of isothermal skin sites of children is useful for hygienic standardization of sauna air exposure.  相似文献   

16.
研究对象是某6063工业铝型材,将建立好的三维模型导入到有限元Altair Hyperxtrude分析软件进行仿真模拟,通过改变型材挤压工艺参数(挤压比、棒料预热温度、模具预热温度、挤压筒预热温度、挤压速度),研究其对金属流动的规律,基于直交表Taguchi方法分析各挤压工艺参数对型材截面速度分布和挤压力的影响规律.结果表明:对于型材截面流动均匀程度指标参数,最佳挤压参数为挤压棒料外径205 mm、挤压垫速度3.2 mm/s、棒料预先加热温度480 ℃、挤压模具预先加热温度470 ℃、挤压筒预先加热温度440 ℃;对于挤压力指标参数,棒料外径200 mm、挤压垫速度1.4 mm/s、棒料预先加热温度490 ℃,挤压模具预先加热温度480 ℃、挤压筒预先加热温度460 ℃.   相似文献   

17.
The effects of anemia during lead exposures were studied using an infant baboon animal model. When the hemoglobin concentration was reduced to less than 70% of normal, a marked blood lead increase was observed and the free erythrocyte porphyrin value, aminolevulinic acid dehydratase activity and reticulocyte counts increased. Special emphasis should be placed on nutritional effects in lead exposures.  相似文献   

18.
PURPOSE: To compare the responses of small intestinal morphological parameters after acute and protracted doses of radiation. MATERIALS AND METHODS: Male C57BL6 mice were examined 6, 24 and 72 h after whole body gamma-irradiation, given either as an acute 5 Gy dose, or as a protracted (continuous) dose of 20 cGy per day for 25 days to a total dose of 5 Gy. Many different structural parameters at both the light microscopical and ultrastructural levels were assessed quantitatively. RESULTS: At different time points following both schedules there were changes in the number of villous enterocytes, goblet cells, lamina propria cells and mitotic figures. Ultrastructural changes occurred in the epithelium. Many of the parameters that showed changes following the protracted schedule appeared to be returning to normal within 3 days of the cessation of radiation, a finding which was in contrast with the acute dose. The protracted schedule produced increases in the number of Paneth cells and in the length of enterocyte microvilli. CONCLUSIONS: Many of the responses that occurred after the protracted schedule suggest that adaptive mechanisms may be being triggered following persistent exposure to radiation.  相似文献   

19.
Respiratory failure following cardiopulmonary bypass (CPB) is a major complication after cardiac surgery. A vital capacity inflation of the lungs, performed before the end of CPB, may improve gas exchange, but the necessity to repeat it is unclear. Therefore, we studied 18 pigs undergoing hypothermic CPB. A vital capacity manoeuvre (VCM) was performed in two groups and consisted of inflating the lungs for 15 s to 40 cm H2O at the end of CPB. In one group, VCM was repeated every hour. The third group served as controls. Atelectasis was studied by CT scan. Intrapulmonary shunt increased after bypass in the controls and improved spontaneously 3 h later without returning to baseline values. From 3 to 6 h after CPB, there was no more improvement and more than 10% atelectasis remained at 6 h. In contrast, the two groups treated before termination of CPB with VCM showed only minor atelectasis and no abnormal changes in gas exchange directly after bypass or later. We conclude that the protective effect of VCM remained for 6 h after bypass, and there was no extra benefit on gas exchange by repeating the VCM.  相似文献   

20.
The prenatal and postnatal environment exerts a long-term influence on the stress-response of the hypothalamic-pituitary-adrenal (HPA) axis. In this study, the long-term effects of prenatal and postnatal manipulations and their related changes on glucocorticoid secretion were examined on metabolic parameters in adult rats. Plasma glucose levels, body weight and basal feeding behavior were measured. We show that modifications of the prenatal and postnatal environment have opposite long-term effects on these parameters, except for blood glucose, which was increased in prenatally stressed animals. Although the mechanisms underlying these phenomena remain to be elucidated, the observations show that perinatal manipulations have long-term effects on metabolic functions related to HPA activity.  相似文献   

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