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The Luminosity Curve of the Protanomalous Fovea   总被引:3,自引:1,他引:3  
Threshold spectral sensitivities (in the dark, or against bright colored backgrounds) are identical in the red-green range for both protanopes (dichromats) and protanomalous trichromatic color defectives. The latter, however, must have an additional photolabile cone pigment in the red-green range, and its presence is revealed by heterochromatic brightness matching through the spectrum (i.e. luminosity curves). The absorption spectrum of the anomalous cone pigment can be inferred from the protanomalous and protanopic luminosity curve, given reasonable assumptions as to how the different cone mechanisms pool their responses. Depending upon these assumptions, the pigment inferred is either (a) dilute solution of the normal red pigment (assumed density 1.0 for the deuteranope) or (b) similar in its absorption spectrum to the normal green pigment but shifted slightly toward the long wave end of the spectrum. Experimental attempts to choose between these alternatives have so far proved equivocal though (b) seems more likely on the basis of indirect evidence.  相似文献   

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Corynebacteria are used for a wide variety of industrial purposes but some species are associated with human diseases. With increasing number of corynebacterial genomes having been sequenced, comparative analysis of these strains may provide better understanding of their biology, phylogeny, virulence and taxonomy that may lead to the discoveries of beneficial industrial strains or contribute to better management of diseases. To facilitate the ongoing research of corynebacteria, a specialized central repository and analysis platform for the corynebacterial research community is needed to host the fast-growing amount of genomic data and facilitate the analysis of these data. Here we present CoryneBase, a genomic database for Corynebacterium with diverse functionality for the analysis of genomes aimed to provide: (1) annotated genome sequences of Corynebacterium where 165,918 coding sequences and 4,180 RNAs can be found in 27 species; (2) access to comprehensive Corynebacterium data through the use of advanced web technologies for interactive web interfaces; and (3) advanced bioinformatic analysis tools consisting of standard BLAST for homology search, VFDB BLAST for sequence homology search against the Virulence Factor Database (VFDB), Pairwise Genome Comparison (PGC) tool for comparative genomic analysis, and a newly designed Pathogenomics Profiling Tool (PathoProT) for comparative pathogenomic analysis. CoryneBase offers the access of a range of Corynebacterium genomic resources as well as analysis tools for comparative genomics and pathogenomics. It is publicly available at http://corynebacterium.um.edu.my/.  相似文献   

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The Luminosity Curve of the Deuteranomalous Fovea   总被引:3,自引:2,他引:3       下载免费PDF全文
Analogous to protans, the two types of deutan color-defectives—the dichromats (deuteranopes) and the anomalous trichromats (deuteranomalous)—do not differ in spectral sensitivity in the red-green range at threshold (either in the dark or against bright colored backgrounds). However, luminosity curves obtained by heterochromatic brightness matching show the latter to be slightly more sensitive in the blue-green, and slightly less so in the red, than the former. Experiment proves that these differences are due (at least in part) to contributions of cones containing the deuteranomalous anomalous pigment which are missing from the deuteranope's eye. The absorption spectrum of the anomalous pigment can be inferred with assumptions (analogous to those already made with protanomalous trichromats) about how the different cone mechanisms pool their responses to yield luminosity. Two alternatives thus revealed are (a) the normal red pigment in dilute solution or (b) a spectrum very similar to that of the normal red pigment but shifted slightly toward the short wave end of the spectrum. Since the spectrum inferred by (a) has the same λmax as the normal red pigment, (a) predicts that deuteranomalous observers will require a negative red primary when matching monochromatic lights of wavelengths near the λmax. This is not observed.  相似文献   

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A small molecule that increases endocannabinoid signalling at sensory nerve terminals enhances analgesia.  相似文献   

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Chronic low back pain (CLBP) was shown to be associated with pathophysiological changes at several levels of the sensorimotor system. Changes in sensory thresholds have been reported but complete profiles of Quantitative Sensory Testing (QST) were only rarely obtained in CLBP patients. The aim of the present study was to investigate comprehensive QST profiles in CLBP at the painful site (back) and at a site distinct from their painful region (hand) and to compare these data with similar data in healthy controls. We found increased detection thresholds in CLBP patients compared to healthy controls for all innocuous stimuli at the back and extraterritorial to the painful region at the hand. Additionally, CLBP patients showed decreased pain thresholds at both sites. Importantly, there was no interaction between the investigated site and group, i.e. thresholds were changed both at the affected body site and for the site distinct from the painful region (hand). Our results demonstrate severe, widespread changes in somatosensory sensitivity in CLBP patients. These widespread changes point to alterations at higher levels of the neuraxis or/and to a vulnerability to nociceptive plasticity in CLBP patients.  相似文献   

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Neuroscience research in China has undergone rapid expansion since 1980. The Neuroscience Research Institute of Peking University, one of the most active neuroscience research groups in China, was founded in 1987. Currently, the institute is overseeing four research areas, i.e., (1) pain and analgesia, (2) drug abuse and acupuncture treatment for drug addiction, (3) the mechanism of neurological degenerative disorders, and (4) the role of neuroglia in central nervous system injury. The institute is simultaneously investigating both theoretical and clinical studies. Acupuncture remains the core of research, while pain and drug abuse form the two disciplines.  相似文献   

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There are two basic categories of pain: physiological pain, which serves an important protective function, and pathological pain, which can have a major negative impact on quality of life in the context of human disease. Major progress has been made in understanding the molecular mechanisms that drive sensory transduction, amplification and conduction in peripheral pain-sensing neurons, communication of sensory inputs to spinal second-order neurons, and the eventual modulation of sensory signals by spinal and descending circuits. This poster article endeavors to provide an overview of how molecular and cellular mechanisms underlying nociception in a physiological context undergo plasticity in pathophysiological states, leading to pain hypersensitivity and chronic pain.  相似文献   

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A Pain in the Fetus: Toward Ending Confusion about Fetal Pain   总被引:2,自引:0,他引:2  
Are fetuses, at any stage of their development, capable of feeling pain? In his paper, ‘Locating the Beginnings of Pain’, Stuart Derbyshire argues that they are not. We argue that he reaches this conclusion by way of conceptual confusion, a misreading of the available scientific data and the inclusion of irrelevant data. Despite his assertion to the contrary, the work of most scientists in the area supports the conclusion that fetuses can feel pain. At the outset we examine the concept of pain and distinguish it from the allied concept of nociception, with which it is sometimes confused. With the relevant conceptual framework in place, we elucidate the problem of determining when, in its development, a human becomes capable of feeling pain. We then examine the available data showing how, on balance, it tends more to support than undermine the claim that fetuses of around 28 to 30 weeks' gestation are capable of feeling pain.  相似文献   

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The primate fovea is the region of the retina responsible for acute vision. This region constitutes less than 5% of the total area of the retina and has not been intensely studied at the molecular level. As a first step in the molecular characterization of the fovea, we have constructed a primary human fovea cDNA library. Experiments confirm that our cDNA library reflects a nonbiased distribution of foveal expressed sequences. Single-pass sequencing was performed on 209 randomly isolated clones from this library. Analysis of the sequences generated reveals that the distributions of fovea clones with either human mitochondrial gene sequences or repetitive elements are different than those observed in cDNA libraries made from other tissues. A significant number of the fovea expressed sequence tags (ESTs) (88, 42.1%) represent novel human ESTs. This suggests that the library will be useful in identifying new human genes. Northern analysis of specific fovea ESTs defined in this study suggests that there are significant quantitative differences in gene expression that distinguish the fovea from the rest of the retina.  相似文献   

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目的:介绍指端切割伤断离皮片改良缝合原位再植术的治疗方法、效果和经验总结,分析影响手术疗效的因素.方法:对37例52指指端切割伤断离皮片行改良缝合原位再植.术后随访1~24个月.结果:术后各型指端切割伤断离皮片成活率分别为:Ⅰ型94.7%;Ⅱ型88.2%;Ⅲ68.8%.在指端切割伤断离皮片改良缝合原位再植术式中,其操作简便,疗效确切.虽存在一定的失败风险,但不失为一种积极的治疗方法.结论:只要切割伤离断的皮片仍较完整,而无手术禁忌证,均可予以改良缝合原位再植.彻底的清创、消毒及所植皮片均匀稳定受压、牢固固定,加上感染的预防是成功的关键.  相似文献   

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