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991.

Objective

Although extensive resting-state functional connectivity (rsFC) changes have been reported in schizophrenia, rsFC changes of the frontal pole (FP) remain unclear. The FP contains several subregions with different connection patterns; however, it is unknown whether the FP subregions are differentially affected in schizophrenia. To explore this possibility, we compared rsFC differences of the FP subregions between schizophrenia patients and healthy controls.

Method

One hundred healthy controls and 91 patients with schizophrenia underwent resting-state functional MRI with a sensitivity-encoded spiral-in (SENSE-SPIRAL) imaging sequence to reduced susceptibility-induced signal loss and distortion. The FP was subdivided into the orbital (FPo), medial (FPm), and lateral (FPl) subregions. Mean fMRI time series were extracted for each FP subregion and entered into a seed-based rsFC analysis.

Results

The FP subregions exhibited differential rsFC patterns in both healthy controls and schizophrenia patients. Direct comparison between groups revealed reduced rsFCs between the bilateral FPl and several cognitive-related regions, including the dorsolateral prefrontal cortex, medial prefrontal cortex, anterior cingulate cortex, posterior cingulate cortex/precuneus, temporal cortex and inferior parietal lobule in schizophrenia. Although the FPl exhibited obvious atrophy, rsFC changes were unrelated to volumetric atrophy in the FPl, to duration of illness, and to antipsychotic medication dosage. No significant differences were observed in the rsFCs of other FP subregions.

Conclusion

These findings suggest a selective (the lateral subregion) functional disconnection of the FP subregions in schizophrenia.  相似文献   
992.
Babiloni F 《IEEE pulse》2012,3(3):21-23
In scientific literature, the most accepted definition of consumer neuroscience or neuromarketing is that it is a field of study concerning the application of neuroscience methods to analyze and understand human behavior related to markets and marketing exchanges. First, it might seem strange that marketers would be interested in using neuroscience to understand consumer's preferences. Yet in practice, the basic goal of marketers is to guide the design and presentation of products in such a way that they are highly compatible with consumer preferences. To understand consumers preferences, several standard research tools are commonly used by marketers, such as personal interviews with the consumers, scoring questionnaries gathered from consumers, and focus groups. The reason marketing researchers are interested in using brain imaging tools instead of simply asking people for their preferences in front of marketing stimuli, arises from the assumption that people cannot (or do not want to) fully explain their preference when explicitly asked. Researchers in the field hypothesize that neuroimaging tools can access information within the consumer's brain during the generation of a preference or the observation of a commercial advertisement. The question of will this information be useful in further promoting the product is still up for debate in marketing literature. From the marketing researchers point of view, there is a hope that this body of brain imaging techniques will provide an efficient tradeoff between costs and benefits of the research. Currently, neuroscience methodology includes powerful brain imaging tools based on the gathering of hemodynamic or electromagnetic signals related to the human brain activity during the performance of a relevant task for marketing objectives. These tools are briefly reviewed in this article.  相似文献   
993.
Abstract

Cardopatum corymbosum is a perennial hemicryptophyta species living on erosion-prone steep slopes where it forms very small, scattered communities that resist soil erosion. The aim of this study was to understand better the life cycle of this species before suggesting its use for eco-engineering purposes to stop soil erosion. We examined anatomical preparations with a light microscope, and plant anatomy was reconstructed by examining sequential cross sections of the stem cut from the shoot apex to the root collar. A single sprout above the root collar produces a rosette of leaves at the beginning of spring and a floral axis at the end of summer. The leaves and the floral axis die at the end of summer, whereas the basal portion of the new stem remains alive and forms, together with the root system, the perennial portion of this plant. This stem zone is named “transition zone” and presents leaf traces converging in the centre where they give rise to a vascular cylinder with a cambium ring dividing a secondary xylem from a secondary phloem. New buds form in the cortex of the transition zone that are quiescent and are not visible externally until the following spring when they resume growth and generate a new sprout. These buds should be considered adventitious because: (1) they form independently of leaves; and (2) their annual production could represent the plant's response to ensure its survival after the loss of the above-ground portion of the stem. Given the efficient resprouting strategy coupled with a perennial root system, C. corymbosum is a good candidate for bio-engineering applications against the soil erosion typical of steep slopes in Mediterranean climates. This species could be considered for intensive re-vegetation in order to produce a protective soil covering.  相似文献   
994.
钦州湾大型底栖动物生态学研究   总被引:1,自引:0,他引:1  
王迪  陈丕茂  马媛 《生态学报》2011,31(16):4768-4777
通过2008年~2009年在钦州湾及附近海域进行的4个航次的大型底栖动物调查,共获大型底栖动物8门62科94种,软体类最多,其次为多毛类,种类季节变化较大。以优势度指数Y>0.02为判别标准,调查区春季优势种为方格皱纹蛤(Periglypta lacerata (Hanley))、刺足掘沙蟹(Scalopidia spinosipes Stimpsom)和独齿围沙蚕(Perinereis cultrifera Grube),夏季优势种为方格皱纹蛤、刺足掘沙蟹和持真节虫,秋季优势种为曲波皱纹蛤和网纹藤壶,冬季优势种为肋鲳螺和方格皱纹蛤。春、夏季优势种变化不大,秋、冬季优势种变化较大,除方格皱纹蛤外均为季节特有种。海区底栖生物平均总密度和平均总生物量分别为439ind./m2和115.14g/m2。与20世纪80年代钦州湾茅尾海调查结果相比,平均栖息密度有所升高,但是平均生物量却有较大程度的降低。底栖动物群落的丰富度指数(D)、Shannon-Wiener多样性指数(H′)和均匀度指数(J′)平均值分别为4.01、1.80和0.73,水平不高。用SPSS软件将各站大型底栖动物的平均密度、平均生物量、多样性指数等生态特征值与水深等理化因子进行了Pearson相关分析,结果表明春季各特征指数与环境因子相关性不显著;夏季丰度、多样性指数和均匀度指数均与水深呈显著负相关,种类数、丰富度和多样性指数与沉积物pH呈显著负相关;秋季密度与硫化物呈显著正相关;冬季生物量与硫化物和有机质均呈显著正相关。  相似文献   
995.
Preliminary studies suggested that the use of compost tea made from spent mushroom substrate (SMS) may be regarded as a potential method for biologically controlling dry bubble disease in button mushroom. The aim of this study was to assess the effect of SMS compost tea on the host, the button mushroom, to ascertain whether the addition of these water extracts has a toxic effect on Agaricus bisporus mycelium growth and on mushroom yield. In vitro experiments showed that the addition of SMS compost tea to the culture medium inoculated with a mushroom spawn grain did not have an inhibitory effect on A. bisporus mycelial growth. The effect of compost teas on the quantitative production parameters of A. bisporus (yield, unitary weight, biological efficiency and earliness) was tested in a cropping trial, applying the compost teas to the casing in three different drench applications. Quantitative production parameters were not significantly affected by the compost tea treatments although there was a slight delay of 0.8-1.4 days in the harvest time of the first flush. These results suggest that compost teas have no fungitoxic effect on A. bisporus so that they can be considered a suitable biocontrol substance for the control of dry bubble disease.  相似文献   
996.
A fructose-rich diet can induce metabolic syndrome, a combination of health disorders that increases the risk of diabetes and cardiovascular diseases. Diet is also known to alter the microbial composition of the gut, although it is not clear whether such alteration contributes to the development of metabolic syndrome. The aim of this work was to assess the possible link between the gut microbiota and the development of diet-induced metabolic syndrome in a rat model of obesity. Rats were fed either a standard or high-fructose diet. Groups of fructose-fed rats were treated with either antibiotics or faecal samples from control rats by oral gavage. Body composition, plasma metabolic parameters and markers of tissue oxidative stress were measured in all groups. A 16S DNA-sequencing approach was used to evaluate the bacterial composition of the gut of animals under different diets. The fructose-rich diet induced markers of metabolic syndrome, inflammation and oxidative stress, that were all significantly reduced when the animals were treated with antibiotic or faecal samples. The number of members of two bacterial genera, Coprococcus and Ruminococcus, was increased by the fructose-rich diet and reduced by both antibiotic and faecal treatments, pointing to a correlation between their abundance and the development of the metabolic syndrome. Our data indicate that in rats fed a fructose-rich diet the development of metabolic syndrome is directly correlated with variations of the gut content of specific bacterial taxa.  相似文献   
997.
为揭示西南地区道路建设对景观格局的影响,基于2015年土地覆被和道路数据,计算了研究区道路核密度与景观指数,在此基础上分析了道路建设的直接、间接和综合影响,探讨了影响的空间异质性和对不同土地覆被影响的特点,指出了各景观指数的适用性。结果表明:(1)道路建设使斑块密度增加,斑块离散化加剧,发生明显的破碎化趋势,同时道路核密度与PD、SHDI、SPLIT变化百分比呈显著正相关,与COHESION、CONTAG、PAFRAC呈显著负相关;(2)道路建设对景观指数的影响程度由大到小依次表现在:破碎化、斑块空间分布形态、聚集连通性,其中PD能很好的表征道路建设对景观破碎化的作用程度,SPLIT在识别破碎化程度高的区域更具优势;(3)不同景观指数具有不同适用性,PAFRAC适用于道路不发达区域,CONTAG适用于道路分布异质性较高的区域,DIVISION适用于人类活动强度不大的区域,COHESION、SPLIT适用于探究道路及伴随的人类活动共同作用的区域,PD、SHDI在探究道路的直接作用时适用性广泛;(4)探究不同土地覆被类型受道路建设的影响,林地优先选取PD、DIVISION;草地优先选取DI...  相似文献   
998.
The viscoelastic properties of mono‐microbial biofilms produced by ocular and reference staphylococcal strains were investigated. The microorganisms were characterized for their haemolytic activity and agr typing and the biofilms, grown on stainless steel surface under static conditions, were analysed by Confocal Laser Scanning Microscopy. Static and dynamic rheometric tests were carried out to determine the steady‐flow viscosity and the elastic and viscous moduli. The analysed biofilms showed the typical time‐dependent behaviour of viscoelastic materials with considerable elasticity and mechanical stability except for Staphylococcus aureus ATCC 29213 biofilm which showed a very fragile structure. In particular, S. aureus 6ME biofilm was more compact than other staphylococcal biofilms studied with a yield stress ranging between 2 and 3 Pa. The data obtained in this work could represent a starting point for developing new therapeutic strategies against biofilm‐associated infections, such as improving the drug effect by associating an antimicrobial agent with a biofilm viscoelasticity modifier.  相似文献   
999.
An in vitro superfusion method was used to test sex hormone release from different kinds of ovarian follicle (growing follicles, postovulatory follicles, and atretic follicles) in the lizard Podarcis sicula sicula. Sex hormone output changes with the stage of follicle evolution and sexual cycle. Previtellogenetic follicles prevail in early-spring quiescent ovaries and secrete mainly progesterone, which is probably utilized at that phase to delay ovarian resumption. In the active ovary, progesterone output from previtellogenetic follicles decreases, whereas vitellogenetic follicles produce a significant amount of 17β-estradiol, which is necessary for sustaining vitellogenin synthesis by the liver and oviduct growth. As follicles become ripe, progesterone production is resumed, and it increases in young postovulatory follicles. This is in line with the functions assigned to the hormone at that phase of the sexual cycle, i.e., the induction of oocyte maturation and the regulation of egg retention in the oviduct. Postovulatory follicles can also synthetize 17β-estradiol. After oviposition, this hormone, which is secreted by the old postovulatory follicles, can reinitiate vitellogenin synthesis, allowing the development of a new oocyte set. Our data confirm that active, although ephemeral, corpora lutea are also formed in oviparous species. A limited contribution to ovarian sex steroid production derives also from atretic follicles, at least at the early stages of the breeding cycle. © 1993 Wiley-Liss, Inc.  相似文献   
1000.
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