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1.
The dynamics of collective decision making is not yet well understood. Its practical relevance however can be of utmost importance, as experienced by people who lost their fortunes in turbulent moments of financial markets. In this paper we show how spontaneous collective “moods” or “biases” emerge dynamically among human participants playing a trading game in a simple model of the stock market. Applying theory and computer simulations to the experimental data generated by humans, we are able to predict the onset of such moments before they actually happen.  相似文献   

2.
The developing uterus, vagina, and cervix of mice whose age ranged from 16 days of gestation to 90 days postnatal were examined for nuclear estrogen receptors (ERs) by autoradiographic and whole cell uptake techniques. ERs were present within mesenchymal cells of these organs throughout the entire period of development and maturation. By contrast, nuclear ER first became detectable by autoradiography in the epithelium of vagina and uterus at 5 and 6 days postnatal, respectively.
As a result of administration of the synthetic estrogen, diethylstilbestrol (DES), consecutively from 16 to 18 days of gestation, uterine and vaginal epithelial cell height was increased and epithelial secretory activity was elevated during the first 48 hr of postnatal life. Also, a single does of DES administered on the 2nd day after birth stimulated epithelial proliferation in the uterus as determined by 3H-thymidine incorporation. These typical estrogenic effects occurred in the absence of nuclear ER within the epithelium. Prenatal DES treatment accelerated the onset of ER activity within the epithelium by 2 to 3 days relative to controls. The possibility that certain effects of estrogen on epithelial differentiation may be mediated indirectly via ER positive mesenchymal cells is discussed.  相似文献   

3.
Abstract To elucidate the effects of herbivory by chrysomelid beetles on Rumex japonicus, rosette leaves were clipped and the subsequent fruit production and root growth were observed. The increase of leaf biomass of some clipped plants was greater than that of control plants, although this varied among individual plants. The root growth of clipped plants was less than that of control plants. Fruit production increased with plant size, and there was no difference in fruit production between clipped and control plants. Reproductive allocation (fruit biomass, relative to fruit biomass plus root growth) increased with plant size; it was greater in clipped plants than in control ones. Based on these results, reproductive allocation strategy against herbivory was discussed.  相似文献   

4.
The regulation of estrogen and progesterone receptor (ER, PR) expression by estradiol (E2) and progesterone (P4) in the oviduct, uterus and cervix of female lambs was studied. The animals received three intramuscular injections of E2, P4 or vehicle with an interval of 24 h and they were slaugthered 24 h after the third injection. Determinations of ER and PR were performed by binding assays and mRNAs of ERα and PR by solution hybridization. High levels of ER and PR in both cervix and oviduct were found in the female lamb, differing from other mammalian species. No significant effects by either E2 or P4 treatment on ER and PR levels in the cervix and oviduct could be observed. E2 treatment increased the mRNA levels of ERa and PR more than 3-fold in the cervix, while P4 treatment increased the mRNA levels of ERa and PR in the uterus. The results show differential effects of gonadal steroids on sex steroid receptor expression along the reproductive tract in female lambs, suggesting that steroid target tissues can modulate responses to the same circulating levels of steroid hormones.  相似文献   

5.
Iodine is a key ingredient in the synthesis of thyroid hormones and also a major factor in the regulation of thyroid function. A local reduction of iodine content in follicular lumen leads to overexpression of local thyroid-stimulating hormone receptor (TSHr), which in turn excessively stimulates the regional thyroid tissue, and result in the formation of nodular goiter. In this study, we investigated the relationship between iodine content and sodium iodide symporter (NIS) expression by using the clinical specimens from patients with nodular goiter and explored the pathogenesis triggered by iodine deficiency in nodular goiter. In total, 28 patients were clinically histopathologically confirmed to have nodular goiter and the corresponding adjacent normal thyroid specimens were harvested simultaneously. Western blot and immunohistochemistry were performed to assay NIS expression and localization in thyrocytes of both nodular goiter and adjacent normal thyroid tissues. NIS expression mediated by iodine in follicular lumen was confirmed by follicular model in vitro. Meanwhile, radioscan with iodine-131were conducted on both nodular goiter and adjacent normal thyroid. Our data showed that NIS expression in nodular goiter was significantly higher than that in adjacent normal tissues, which was associated with low iodine in the follicular lumen. Abnormal localization of NIS and lower amount of radioactive iodine-131 were also found in nodular goiter. Our data implied that low iodine in the follicular lumen caused by cytoplasm mis-localization of NIS may induce nodular goiter.  相似文献   

6.
Sleep spindles and K-complexes (KCs) define stage 2 NREM sleep (N2) in humans. We recently showed that KCs are isolated downstates characterized by widespread cortical silence. We demonstrate here that KCs can be quasi-synchronous across scalp EEG and across much of the cortex using electrocorticography (ECOG) and localized transcortical recordings (bipolar SEEG). We examine the mechanism of synchronous KC production by creating the first conductance based thalamocortical network model of N2 sleep to generate both spontaneous spindles and KCs. Spontaneous KCs are only observed when the model includes diffuse projections from restricted prefrontal areas to the thalamic reticular nucleus (RE), consistent with recent anatomical findings in rhesus monkeys. Modeled KCs begin with a spontaneous focal depolarization of the prefrontal neurons, followed by depolarization of the RE. Surprisingly, the RE depolarization leads to decreased firing due to disrupted spindling, which in turn is due to depolarization-induced inactivation of the low-threshold Ca2+ current (IT). Further, although the RE inhibits thalamocortical (TC) neurons, decreased RE firing causes decreased TC cell firing, again because of disrupted spindling. The resulting abrupt removal of excitatory input to cortical pyramidal neurons then leads to the downstate. Empirically, KCs may also be evoked by sensory stimuli while maintaining sleep. We reproduce this phenomenon in the model by depolarization of either the RE or the widely-projecting prefrontal neurons. Again, disruption of thalamic spindling plays a key role. Higher levels of RE stimulation also cause downstates, but by directly inhibiting the TC neurons. SEEG recordings from the thalamus and cortex in a single patient demonstrated the model prediction that thalamic spindling significantly decreases before KC onset. In conclusion, we show empirically that KCs can be widespread quasi-synchronous cortical downstates, and demonstrate with the first model of stage 2 NREM sleep a possible mechanism whereby this widespread synchrony may arise.  相似文献   

7.

Objective

To compare life satisfaction between women with successful or unsuccessful outcome after assisted reproductive treatment (ART) by taking into account the time since the last ART.

Design

Cohort study.

Setting

Tertiary hospital.

Patients

A total of 987 consecutive women who had undergone ART during 1996–2007 were invited and altogether 505 women participated in the study.

Interventions

A postal enquiry with a life satisfaction scale.

Main Outcome Measure

Self-reported life satisfaction in respect to the time since the last ART.

Results

In general, women who achieved a live birth after ART had a significantly higher life satisfaction than those who had unsuccessful ART, especially when compared in the first three years. The difference disappeared in the time period of 6–9 years after ART. The unsuccessfully treated women who had a child by some other means before or after the unsuccessful ART had comparable life satisfaction with successfully treated women even earlier.

Conclusions

Even if unsuccessful ART outcome is associated with subsequent lower level of life satisfaction, it does not seem to threaten the long-term wellbeing.  相似文献   

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10.
Abstract: Administration of estradiol benzoate to gonadectomized female rats results in up-regulation of CNS γ-aminobutyric acid (GABA) receptors. The increase of [3H]muscimol binding activity is observed in six of the seven brain areas examined. The same treatment, performed in castrated male or and rogenized female rats, induced an increase of [3H]muscimol binding only in the striatum. Evidence is provided suggesting that the dimorphic sensitivity of GABA receptor is not correlated with the difference in spontaneous motor activity reported between male and female rats.  相似文献   

11.

Objective

The purpose of this study was to analyze the clinical features and prognostic factors of surgical outcome of foot drop caused by lumbar degenerative disease and put forward the clinical stage.

Methods

We retrospectively reviewed 135 patients with foot drop due to lumbar degenerative disease. The clinical features and mechanism were analyzed. Age, sex, duration of palsy, preoperative muscle strength of tibialis anterior (TA), sensation defect of affected lower limb, affected foot, diagnosis and compressed nerve roots were recorded and compared with surgical outcome.

Results

Foot drop was observed in 8.1% of all inpatients of lumbar degenerative disease. L5 nerve root compression was observed in 126 of all 135 patients (93.3%). Single, double and triple roots compression was observed respectively in 43, 83, and 9 patients (31.9%, 61.5%, and 6.6%). But there was no significant relationship between preoperative muscle strength of TA and the number of compressed roots. The muscle strength of TA was improved in 113 (83.7%) patients after surgery, but it reached to >=4 in only 21 (15.6%) patients. Improvement of the muscle strength of TA was almost stable at the 6-month follow-up. At the last follow-up, the muscle strength of TA was 1, 2, 3, 4, 5 respectively in 28, 24, 62, 13, 8 patients. Multivariate logistic regression showed duration of palsy (p=0.0360, OR=2.543), preoperative muscle strength of TA (p=0.0064, OR=5.528) and age (p=0.0309, OR=3.208) were factors that influenced recovery following an operation.

Conclusions

L5 nerve root was most frequently affected. The muscle strength of TA improved in most patients after surgery, but few patients can get a good recovery from foot drop. Patients of shorter duration of palsy, better preoperative muscle strength of TA and younger age showed a better surgical outcome.  相似文献   

12.
There is increasing necessity for including an evaluation of psychosocial as well as biomedical factors when assessing the need for surgical intervention and its possible outcomes. Potential problems between patient and surgeon can arise when these factors are not taken into account. Recent behavioral science literature supports the use of a conceptual framework and concise clinical method for evaluating psychosocial factors and negotiating treatment with a patient. Such a method may be useful in reducing patient-surgeon conflicts and the negative outcomes (such as patient noncompliance, dissatisfaction, medical-legal suits and poor patient care) that can result when such an assessment is not mutually discussed.  相似文献   

13.
Mycopathologia - Cryptococcosis by Cryptococcus gattii occurs mainly in immunocompetent hosts, however, during the last decades, a growing number of cases in immunocompromised individuals have been...  相似文献   

14.
We determined whether short-term, posthatch oral exposure to estradiol benzoate (EB) or the industrial surfactant octylphenol (OP) could impair the reproductive performance of zebra finches. If so, naturally occurring phytoestrogens and xenoestrogens might influence reproduction in wild populations. Chicks were given oral administration of 10 or 100 nmol EB per gram of body mass (earlier work showed the latter to be the minimum oral dose required to maximally masculinize female song nuclei) or an equimolar amount of OP daily from 5 through 11 days of age. Canola oil was used as a vehicle and control. Reproductive testing was done either in individual pair cages or in communal cages that permitted self-selection of mates, N = 10 pairs per group. Pairs consisted of EB-treated males and females, EB-treated males paired with canola-treated females, vice versa, and canola-treated males and females. Posthatch EB treatment produced sex-specific impairments in reproduction that, in some instances, were additive when both sexes were treated. Egg production was reduced and egg breakage was increased in 100 nmol/g EB-treated male and female pairs. The incidence of missing eggs was increased in 10 nmol/g EB-treated male and female pairs. Candled fertility was reduced in both groups containing 100 nmol/g EB-treated males. The number of hatched chicks was severely reduced in all EB-treated groups. No adverse effects of OP treatment were detected. These significant treatment effects (all P < 0.05) show that posthatch EB treatment profoundly disrupts the reproductive performance of zebra finches, suggesting that exposure to estrogens in the wild could impair the reproductive performance of wild populations.  相似文献   

15.
In order to reveal the mechanism of the Maillard reaction between proteins and reducing sugars, unmodified and chemically modified lysozymes were incubated with and without glucose at 50°C and 75% relative humidity in the solid state. Incubation of unmodified lysozyme with glucose resulted in browning and polymerization of the protein, and noticeable losses of arginine, lysine, and tryptophan residues. Those changes were little affected by the presence of an oxygen adsorber. Acetylation of lysozyme almost completely prevented those changes, indicating that the reaction of free amino groups of the protein with glucose is essential at the initial stage of these changes.

Incubation of lysozyme the arginine residues of which were masked with 1,2-cyclohexane-dione (CHD) resulted in almost the same changes as above even in the absence of glucose. Those changes could be explained as caused by the action of CHD released from the arginine residues. This similarity in the effects on protein of CHD and glucose implies that dicarbonyl compounds are key components at the secondary stage of the Maillard reaction between proteins and reducing sugars.  相似文献   

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17.
转基因作物的全球大规模种植引起了全世界的广泛关注甚至争议。经过遗传改良并具有自然选择优势的转基因作物进入商品化种植,可能将带来环境生物安全的顾虑。在这些生物安全的顾虑中,转基因通过花粉介导的基因漂移向栽培作物的野生近缘种逃逸及其导致的潜在环境风险,就是世人最为关注的环境生物安全问题之一。包括中国在内的许多国家,在转基因作物进行商品化生产之前都必须对转基因逃逸及其带来的潜在环境风险进行严格评价。按照风险评价的框架,转基因向野生近缘种逃逸及其带来潜在环境风险的评价包括3个连续的步骤:1)检测转基因漂移到作物野生近缘种的频率;2)分析转基因在野生近缘种中的表达;3)确定转基因对野生近缘种群体适合度和进化潜力的影响。大量基因漂移的研究结果已表明,转基因通过基因漂移向栽培作物邻近的野生近缘种群体逃逸难以避免,而转基因也会在作物的野生近缘种群体中正常表达。因此分析和评价转基因为野生近缘种带来的适合度效应,对于转基因逃逸及其环境风险的评价至关重要。对适合度的概念及其进化意义进行介绍,并对如何利用转基因的适合度效应分析转基因逃逸的环境风险,以及对此类环境风险进行研究和评价的具体方法予以介绍。上述知识和方法的掌握将有助于人们对转基因作物环境生物安全及其评价的全面理解。  相似文献   

18.
Host Determinants of Helicobacter pylori Infection and Its Clinical Outcome   总被引:5,自引:0,他引:5  
Greater than one-half of the world's population harbors Helicobacter pylori. The majority of infected individuals, however, remain asymptomatic, with only 10% to 20% developing diseases, including peptic ulcer disease, gastric cancer, and gastric mucosa–associated lymphoid tissue lymphoma. This article reviews host factors that may predispose an individual to both the acquisition of H. pylori infection and subsequent clinical outcome. Individuals with specific blood group antigens and human leukocyte antigen genotypes may be more susceptible to H. pylori infection. Additional factors, such as the age of acquisition, the host immune response, the site of infection, acid secretion, and interactions with nonhost factors (including bacterial virulence factors and environmental influences) may play a role in determining clinical outcome. Further investigation is required to clarify the mechanisms by which these interactions occur and, more critically, to determine their relative importance. This knowledge will enable the identification of individuals at risk of developing clinical disease with H. pylori infection.  相似文献   

19.
目的建立卷尾猴正常月经周期卵泡生长发育变化规律及排卵的超声监测(ultrasound examination,US)技术。方法采用阴道细胞涂片及超声监测技术,对5只卷尾猴连续3个周期检查阴道细胞变化,对卵泡生长发育进行超声监测。结果阴道脱落细胞在生殖周期内呈周期性变化,月经周期为(21.13±2)d。阴道细胞学涂片显示卷尾猴的月经周期分为以下各期:月经期(menstrual phase,M)、滤泡期(follicular phase,F)、排卵前期(pre-ovulationphase,Po),黄体期(luteal phase,L)。US技术在滤泡期及排卵前期可观测到直径约3~9 mm的优势卵泡(dominantfollicle,DF)的生长过程。当DF较前一天至少小10%,轮廓不规则,回声较以前强,阴道细胞涂片显示淋巴细胞出现,提示排卵已发生,黄体开始形成。结论B型超声技术能实时监测卷尾猴的卵泡生长发育过程,预知优势卵泡排卵时间。  相似文献   

20.
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