Whole-Brain Functional Connectivity Identification of Functional Dyspepsia

Recent neuroimaging studies have shown local brain aberrations in functional dyspepsia (FD) patients, yet little attention has been paid to the whole-brain resting-state functional network abnormalities. The purpose of this study was to investigate whether FD disrupts the patterns of whole-brain networks and the abnormal functional connectivity could reflect the severity of the disease. The dysfunctional interactions between brain regions at rest were investigated in FD patients as compared with 40 age- and gender- matched healthy controls. Multivariate pattern analysis was used to evaluate the discriminative power of our results for classifying patients from controls. In our findings, the abnormal brain functional connections were mainly situated within or across the limbic/paralimbic system, the prefrontal cortex, the tempo-parietal areas and the visual cortex. About 96% of the subjects among the original dataset were correctly classified by a leave one-out cross-validation approach, and 88% accuracy was also validated in a replication dataset. The classification features were significantly associated with the patients’ dyspepsia symptoms, the self-rating depression scale and self-rating anxiety scale, but it was not correlated with duration of FD patients (p>0.05). Our results may indicate the effectiveness of the altered brain functional connections reflecting the disease pathophysiology underling FD. These dysfunctional connections may be the epiphenomena or causative agents of FD, which may be affected by clinical severity and its related emotional dimension of the disease rather than the clinical course.     

A New Functional Equation Analogous to CAUCHT-PEXIDER Functional Equation and its Application

The CAUCHY-PEXIDER functional equation H (x±y)=F(x) G(y) is generalized to the form H ((x^c±y^c)^1/c) = F(x) G(y), c≠0, assuming the function H(x) possesses a measurable majorant on a set of positive measure. The result is used to obtain a characterization of WEIBULL distribution. This functional equation is generalized to functions of vector variables.     

Robust Classification of Functional and Quantitative Image Data Using Functional Mixed Models

Summary This article introduces new methods for performing classification of complex, high‐dimensional functional data using the functional mixed model (FMM) framework. The FMM relates a functional response to a set of predictors through functional fixed and random effects, which allows it to account for various factors and between‐function correlations. The methods include training and prediction steps. In the training steps we train the FMM model by treating class designation as one of the fixed effects, and in the prediction steps we classify the new objects using posterior predictive probabilities of class. Through a Bayesian scheme, we are able to adjust for factors affecting both the functions and the class designations. While the methods can be used in any FMM framework, we provide details for two specific Bayesian approaches: the Gaussian, wavelet‐based FMM (G‐WFMM) and the robust, wavelet‐based FMM (R‐WFMM). Both methods perform modeling in the wavelet space, which yields parsimonious representations for the functions, and can naturally adapt to local features and complex nonstationarities in the functions. The R‐WFMM allows potentially heavier tails for features of the functions indexed by particular wavelet coefficients, leading to a down‐weighting of outliers that makes the method robust to outlying functions or regions of functions. The models are applied to a pancreatic cancer mass spectroscopy data set and compared with other recently developed functional classification methods.     

Functional genomics and metal metabolism

Metal ions are essential nutrients, yet they can also be toxic if they over-accumulate. Homeostatic mechanisms and detoxification systems therefore precisely control their intracellular levels and distribution. The tools of functional genomics are rapidly accelerating understanding in this field, particularly in the yeast Saccharomyces cerevisiae.     

Functional morphology and evolutionary biology

In this study the relationship between functional morpholoy and evolutionary biology is analysed by confronting the main concepts in both disciplines.Rather than only discussing this connection theoretically, the analysis is carried out by introducing important practical and experimental studies, which use aspects from both disciplines. The mentioned investigations are methodologically analysed and the consequences for extensions of the relationship are worked out. It can be shown that both disciplines have a large domain of their own and also share a large common ground. Many disagreements among evolutionary biologists can be reduced to differences in general philosophy (idealism vs. realism), selection of phenomenona (structure vs. function), definition of concepts (natural selection) and the position of the concept theory as an explaining factor (neutralists vs. selectionists, random variation, determinate selection, etc.).The significance of functional morphology for evolutionary biology, and vice versa depends on these differences. For a neo-Darwinian evolutionary theory, contributions from functional and ecological morphology are indispensable. Of ultimate importance are the notions of internal selection and constraints in the constructions determining further development. In this context the concepts of random variation and natural selection need more detailed definition.The study ends with a recommendation for future research founded in a system-theoretical or structuralistic conception.     

Functional analyses and their justification

Responses

Functional analyses and their justification     

水稻突变体与功能基因组学

突变体是功能基因组学研究的重要材料。本文综述了水稻突变体的创制方法、变异的机制、水稻突变体/基因分类和数量、克隆的水稻重要基因的研究进展, 包括1 698个水稻突变体/基因的分类和43个克隆的水稻突变体基因, 并提出了利用水稻突变体的展望。     

桉树基因组和功能基因组

本文就桉树基因组和功能基因组的研究进展作介绍。     

Functional evaluation and rehabilitation engineering

Life is complex and all about movement, which allows us to interact with the environment and communicate with each other. The human nervous system is capable of performing a simultaneous and integrated control of 100-150 mechanical degrees of freedom of movement in the body via tensions generated by about 700 muscles. In its widest context, movement is carried out by a sensory motor system comprising multiple sensors (visual,auditory, and proprioceptive),multiple actuators (muscles acting on the skeletal system),and an intermediary processor that can be summarized as a multiple-input–multiple-output nonlinear dynamic time-varying control system. This grand control system is capable of responding with remarkable accuracy,speed, appropriateness,versatility, and adaptability to a wide spectrum of continuous and discrete stimuli and conditions and is certainly orders of magnitude more complex and sophisticated than the most advanced robotic systems currently available. In the last decades,a great deal of research has been carried out in the fields of functional evaluation of human performance and rehabilitation engineering. These fields combine knowledge, concepts, and methods from across many disciplines (e.g., biomechanics,neuroscience, and physiology), with the aim of developing apparatuses and methods fort he measurement and analysis of complex sensory motor performance and the ultimate goal of enhancing the execution of different tasks in both healthy people and persons with reduced capabilities from different causes (injury, disease, amputation,and neural degeneration).     

Functional and ecological xylem anatomy

Cohesion-tension transport of water is an energetically efficient way to carry large amounts of water from the roots up to the leaves. However, the cohesion-tension mechanism places the xylem water under negative hydrostatic pressure (P_x), rendering it susceptible to cavitation. There are conflicts among the structural requirements for minimizing cavitation on the one hand vs maximizing efficiency of transport and construction on the other. Cavitation by freeze-thaw events is triggered by in situ air bubble formation and is much more likely to occur as conduit diameter increases, creating a direct conflict between conducting efficiency and sensitivity to freezing induced xylem failure. Temperate ring-porous trees and vines with wide diameter conduits tend to have a shorter growing season than conifers and diffuse-porous trees with narrow conduits. Cavitation by water stress occurs by air seeding at interconduit pit membranes. Pit membrane structure is at least partially uncoupled from conduit size, leading to a much less pronounced trade-off between conducting efficiency and cavitation by drought than by freezing. Although wider conduits are generally more susceptible to drought-induced cavitation within an organ, across organs or species this trend is very weak. Different trade-offs become apparent at the level of the pit membranes that interconnect neighbouring conduits. Increasing porosity of pit membranes should enhance conductance but also make conduits more susceptible to air seeding. Increasing the size or number of pit membranes would also enhance conductance, but may weaken the strength of the conduit wall against implosion. The need to avoid conduit collapse under negative pressure creates a significant trade-off between cavitation resistance and xylem construction cost, as revealed by relationships between conduit wall strength, wood density and cavitation pressure. Trade-offs involving cavitation resistance may explain the correlations between wood anatomy, cavitation resistance, and the physiological range of negative pressure experienced by species in their native habitats.     

Functional morphology and evolutionary ecology

Functional morphology studies physico-chemical properties and biological roles of organs. If applied to fossils this approach is connected with specific methodological problems. The fields of application of functional morphology in paleontology are illustrated with examples. In a working concept it is shown how the results of functional morphology can be integrated into an account of the evolutionary ecology of fossil taxa.     

水稻突变体与功能基因组学

突变体是功能基因组学研究的重要材料。本文综述了水稻突变体的创制方法、变异的机制、水稻突变体,基因分类和数量、克隆的水稻重要基因的研究进展,包括1698个水稻突变体,基因的分类和43个克隆的水稻突变体基因,并提出了利用水稻突变体的展望。     

Functional genomics and enzyme evolution

Computational analysis of complete genomes, followed by experimental testing of emerging hypotheses — the area of research often referred to as functional genomics — aims at deciphering the wealth of information contained in genome sequences and at using it to improve our understanding of the mechanisms of cell function. This review centers on the recent progress in the genome analysis with special emphasis on the new insights in enzyme evolution. Standard methods of predicting functions for new proteins are listed and the common errors in their application are discussed. A new method of improving the functional predictions is introduced, based on a phylogenetic approach to functional prediction, as implemented in the recently constructed Clusters of Orthologous Groups (COG) database (available at http://www.ncbi.nlm.nih.gov/COG). This approach provides a convenient way to characterize the protein families (and metabolic pathways) that are present or absent in any given organism. Comparative analysis of microbial genomes based on this approach shows that metabolic diversity generally correlates with the genome size-parasitic bacteria code for fewer enzymes and lesser number of metabolic pathways than their free-living relatives. Comparison of different genomes reveals another evolutionary trend, the non-orthologous gene displacement of some enzymes by unrelated proteins with the same cellular function. An examination of the phylogenetic distribution of such cases provides new clues to the problems of biochemical evolution, including evolution of glycolysis and the TCA cycle.This revised version was published online in October 2005 with corrections to the Cover Date.     

功能基因组学及其研究方法

随着水稻基因组测序工作的完成以及人类基因组计划(HGP)的顺利进行,生命科学的研究已经进入了后基因组时代。对功能基因组学的研究方法进行了综述,主要包括:微阵列、基因表达系列分析、反义RNA和RNAi、基因敲除、基因陷阱、蛋白质组、生物信息学和功能基因组系统学等。