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Relative Simplicity (relative + simplicity)
Selected AbstractsExtracellular interactome of the FGF receptor,ligand system: Complexities and the relative simplicity of the wormDEVELOPMENTAL DYNAMICS, Issue 2 2009Urszula M. Polanska Abstract Fibroblast growth factors (FGFs) and their receptors (FGFRs) regulate a multitude of biological functions in embryonic development and in adult. A major question is how does one family of growth factors and their receptors control such a variety of functions? Classically, specificity was thought to be imparted by alternative splicing of the FGFRs, resulting in isoforms that bind specifically to a subset of the FGFs, and by different saccharide sequences in the heparan sulfate proteoglycan (HSPG) co-receptor. A growing number of noncanonical co-receptors such as integrins and neural cell adhesion molecule (NCAM) are now recognized as imparting additional complexity to classic FGFR signaling. This review will discuss the noncanonical FGFR ligands and speculate on the possibility that they provide additional and alternative means to determining the functional specificity of FGFR signaling. We will also discuss how invertebrate models such as C. elegans may advance our understanding of noncanonical FGFR signaling. Developmental Dynamics 238:277,293, 2009. © 2008 Wiley-Liss, Inc. [source] Measuring metabolic rate in the field: the pros and cons of the doubly labelled water and heart rate methodsFUNCTIONAL ECOLOGY, Issue 2 2004P. J. Butler Summary 1Measuring the metabolic rate of animals in the field (FMR) is central to the work of ecologists in many disciplines. In this article we discuss the pros and cons of the two most commonly used methods for measuring FMR. 2Both methods are constantly under development, but at the present time can only accurately be used to estimate the mean rate of energy expenditure of groups of animals. The doubly labelled water method (DLW) uses stable isotopes of hydrogen and oxygen to trace the flow of water and carbon dioxide through the body over time. From these data, it is possible to derive a single estimate of the rate of oxygen consumption () for the duration of the experiment. The duration of the experiment will depend on the rate of flow of isotopes of oxygen and hydrogen through the body, which in turn depends on the animal's size, ranging from 24 h for small vertebrates to up to 28 days in Humans. 3This technique has been used widely, partly as a result of its relative simplicity and potential low cost, though there is some uncertainty over the determination of the standard error of the estimate of mean . 4The heart rate (fH) method depends on the physiological relationship between heart rate and . 5If these two quantities are calibrated against each other under controlled conditions, fH can then be measured in free-ranging animals and used to estimate . 6The latest generation of small implantable data loggers means that it is possible to measure fH for over a year on a very fine temporal scale, though the current size of the data loggers limits the size of experimental animals to around 1 kg. However, externally mounted radio-transmitters are now sufficiently small to be used with animals of less than 40 g body mass. This technique is gaining in popularity owing to its high accuracy and versatility, though the logistic constraint of performing calibrations can make its use a relatively extended process. [source] Fluorescent, molecularly imprinted thin-layer films based on a common polymer,JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007Piotr Cywinski Abstract Fluorescent, molecularly imprinted polymer thin films, with cyclic guanosine 3,,5,-monophosphate (cGMP) as a template and 1,2-diphenyl-6-vinyl-1H -pyrazole-[3,4- b]-quinoline as a fluorescent receptor, were prepared according to a method based on commercially available poly (methyl methacrylate). This method of preparation predicts photoinduced crosslinking in the mixture of polymer chains and involved components. The advantages of this method are the relative simplicity of its preparation and the fact that a common polymer can be used. The spin-coated thin-layer films of imprinted and nonimprinted polymers were studied with the use of fluorescence microscopy with a scanning range of 80 × 80 ,m. A strong fluorescence quenching effect was observed when a cGMP-imprinted film was incubated in aqueous solutions of cGMP, but a comparatively small effect was observed for a nonimprinted polymer and when an imprinted film was incubated with cyclic adenosine 3,,5,-monophosphate (cAMP). The separation factor by the imprinted polymer was determined to be 2.55 for cGMP against cAMP. The obtained polymeric sensor appeared to be stable during subsequent measurements after rewashing and readsorption. The homogeneity of the surface of the polymer film, dependent on the method of film preparation, was also studied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 105: 229,235, 2007 [source] New and old trends in chemometrics.JOURNAL OF CHEMOMETRICS, Issue 8-10 2002How to deal with the increasing data volumes in R&D&P (research, development, process modeling, production), with examples from pharmaceutical research Abstract Chemometrics was started around 30 years ago to cope with and utilize the rapidly increasing volumes of data produced in chemical laboratories. The methods of early chemometrics were mainly focused on the analysis of data, but slowly we came to realize that it is equally important to make the data contain reliable information, and methods for design of experiments (DOE) were added to the chemometrics toolbox. This toolbox is now fairly adequate for solving most R&D problems of today in both academia and industry, as will be illustrated with a few examples. However, with the further increase in the size of our data sets, we start to see inadequacies in our multivariate methods, both in their efficiency and interpretability. Drift and non-linearities occur with time or in other directions in data space, and models with masses of coefficients become increasingly difficult to interpret and use. Starting from a few examples of some very complicated problems confronting chemical researchers today, possible extensions and generalizations of the existing chemometrics methods, as well as more appropriate preprocessing of the data before the analysis, will be discussed. Criteria such as scalability of methods to increasing size of problems and data, increasing sophistication in the handling of noise and non-linearities, interpretability of results, and relative simplicity of use will be held as important. The discussion will be made from a perspective of the evolution of the scientific methodology as driven by new technology, e.g. computers, and constrained by the limitations of the human brain, i.e. our ability to understand and interpret scientific and data analytical results. Quilt-PCA and Quilt-PLS presented here address and offer a possible solution to these problems. Copyright © 2002 John Wiley & Sons, Ltd. [source] Noninvasive blood flow imaging for real-time feedback during laser therapy of port wine stain birthmarksLASERS IN SURGERY AND MEDICINE, Issue 3 2008Yu-Chih Huang MS Abstract Background and Objectives During laser therapy of port wine stain (PWS) birthmarks, regions of persistent perfusion may exist. Immediate retreatment of such regions may improve PWS laser therapeutic outcome. To address this need, we propose use of laser speckle imaging (LSI) to provide real-time, quantitative feedback during laser surgery. Herein, we present in vitro and in vivo data collected with a clinic-based LSI instrument. Study Design/Materials and Methods Prior to clinical implementation, we first investigated three aspects of LSI deemed important for clinical imaging: (1) instrument depth of field (DOF); (2) effects of laser irradiance on speckle flow index (SFI) values; and (3) measurement repeatability. Clinical measurements were acquired from the lesions of PWS patients immediately prior to and after laser therapy at the Beckman Laser Institute. Results Our preclinical data suggest the following: (1) instrument DOF was ,1 cm; (2) quantitative flow characterization with LSI was practically unaffected at normalized irradiance values between 0.06 and 0.5; and (3) our LSI instrument was capable of highly reproducible SFI values. From our clinical measurements, we found that the relative difference between blood perfusion in PWS lesions and adjacent normal skin was highly variable. Based on SFI images, the perfusion of PWS skin is sometimes indistinguishable from that of adjacent normal skin. With laser therapy, we measured a global decrease in blood perfusion, and we frequently observed distinct regions of persistent perfusion. Conclusions Our results demonstrate the potential role of image-guided laser therapy of PWS birthmarks. LSI is a promising tool for noninvasive blood flow characterization during laser therapy due to its relative simplicity and low cost. Laser Surg. Med. 40:167,173, 2008. © 2008 Wiley-Liss, Inc. [source] Looking inside the box: bacterial transistor arraysMOLECULAR MICROBIOLOGY, Issue 1 2008Thomas S. Shimizu Summary One often compares cells to computers, and signalling proteins to transistors. Location and wiring of those molecular transistors is paramount in defining the function of the subcellular chips. The bacterial chemotactic sensing apparatus is a large, stable assembly consisting of thousands of receptors, signal transducing kinases and linking proteins, and is responsible for the motile response of the bacterium to environmental signals, whether chemical, mechanical, or thermal. Because of its rich functional repertoire despite its relative simplicity, this chemosome has attracted much attention from both experimentalists and theoreticians, and the bacterial chemotaxis response becoming a benchmark in Systems Biology. Structural and functional models of the chemotactic device have been developed, often based on particular assumptions regarding the topology of the receptor lattice. In this issue of Molecular Microbiology, Briegel et al. provide a detailed view of the receptor arrangement, unravelling the wiring of the molecular signal processors. [source] Dinoflagellate mitochondrial genomes: stretching the rules of molecular biologyBIOESSAYS, Issue 2 2009Ross F. Waller Abstract Mitochondrial genomes represent relict bacterial genomes derived from a progenitor ,-proteobacterium that gave rise to all mitochondria through an ancient endosymbiosis. Evolution has massively reduced these genomes, yet despite relative simplicity their organization and expression has developed considerable novelty throughout eukaryotic evolution. Few organisms have reengineered their mitochondrial genomes as thoroughly as the protist lineage of dinoflagellates. Recent work reveals dinoflagellate mitochondrial genomes as likely the most gene-impoverished of any free-living eukaryote, encoding only two to three proteins. The organization and expression of these genomes, however, is far from the simplicity their gene content would suggest. Gene duplication, fragmentation, and scrambling have resulted in an inflated and complex genome organization. Extensive RNA editing then recodes gene transcripts, and trans-splicing is required to assemble full-length transcripts for at least one fragmented gene. Even after these processes, messenger RNAs (mRNAs) lack canonical start codons and most transcripts have abandoned stop codons altogether. [source] | ||||||||||