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1.
Complicated ecosystems and the high non-linearity of evolution has made biology more adaptable to a variety of environments. The relationship between life and environment demands a dynamic definition of niche and its measurement. In this paper we propose a model of niche with dynamic character based on the “broad band” effect in type-2 fuzzy sets. The niche in this definition is an interval in each ecological dimension which is dynamic in character and depends on the actual environment. We also give formulas for niche width and niche overlap. We compute the niche width and overlap for plants and animals and then compare these results with previous results. The results for niche width in this paper reflect the diversity of resources used by species or communities. The results for niche overlap demonstrate overlap under different environmental conditions. The results are, moreover, intervals, which could provide more information. The model in this paper could therefore be used to describe the state of every resource comprehensively, reflecting the interaction between species and environment. 相似文献
2.
Rob C. A. Keller 《Food biophysics》2018,13(2):139-146
The results of the search for potential helical lipid binding regions in a number of well-known food proteins is described. All selected food proteins have either well-described or strong indications of protein-lipid interaction features. The results are obtained with the aid of a number of selected bioinformatics tools. The identified potential lipid binding regions either correspond nicely with regions demonstrated experimentally or can be identified as novel lipid binding regions. The results are discussed in relation to earlier found experimental results and if relevant are discussed in mechanistic terms as well. A possible general use of the approach as used in this study is discussed as well. The in this study described approach can be used as a tool to come to a more focused approach for further research of yet unknown proteins. It is also possible to use this approach for more directed research when it comes to for example rational functional design of proteins for particular desired features like the emulsifying or foaming ability of the protein of interest. 相似文献
3.
The purpose of this research is to investigate the relative humidity effects on skin temperature and skin wettedness for different operative temperatures. For this aim, thermal interactions between human body and environment are simulated. In this simulation, Gagge 2-node model is used but includes some significant modifications. The simulation is to apply the Gagge 2-node model to individual segments rather than to whole body. Also, the results of the simulation are compared with present measurements, and available experimental data and simulated results in the literature in order to present reliability of the 16 segments-Gagge 2-node model. It is determined that the simulation results are in good agreement with measured results obtained from present experiments, and simulated results and experimental data in the literature. 相似文献
4.
In this paper we calculate the hydrogen ion titration curves and associated surface potential for a lattice of discrete sites by numerically solving a titration equation constructed by expanding the partition function for the lattice in powers of the density of charged groups. The titration equations were calculated for several different lattice spacings and ionic strengths of the bathing solution. The results of applying this theory to several simple models of the membrane-solution interface is compared to the corresponding results obtained via the uniform-charge model. 相似文献
5.
A lot of in-house polymerase chain reaction assays have been reported for diagnosis of invasive aspergillosis and disseminated candidosis. Encouraging results have been published to anticipate the diagnosis over the conventional microbiological methods. However, the absence of standardized methods has led to diverging results. As a consequence, these tests are not recognized as consensual diagnostic criteria, in contrast with some antigenemia detection kits. The major breakthrough for improving the results of these methods is the emergence of real-time technologies. This markedly improves the reliability of the PCR results by dramatically decreasing the risk of false positive results due to PCR products carryover. Moreover, using the quantitative results provided by this technique, this allows to rapidly compare the efficiency of primers, probes, and DNA extraction methods. Therefore, the hope is to identify the more specific and sensitive parameters to implement comparative studies. Automated DNA extraction should also be useful to achieve this goal.Whatever sophisticated technology is used, we still have to define the meaning of detecting nucleic acids in a given clinical sample. This seems simple in normally sterile anatomical sites but less obvious for example in respiratory specimens for invasive aspergillosis or in blood for candidosis in heavily colonized patients. Additional studies of the kinetics of fungal DNA are needed. The development of real-time technology should improve our knowledge in order to give the clinicians informative clues for making a decision. 相似文献
6.
A lot of in-house polymerase chain reaction assays have been reported for diagnosis of invasive aspergillosis and disseminated candidosis. Encouraging results have been published to anticipate the diagnosis over the conventional microbiological methods. However, the absence of standardized methods has led to diverging results. As a consequence, these tests are not recognized as consensual diagnostic criteria, in contrast with some antigenemia detection kits. The major breakthrough for improving the results of these methods is the emergence of real-time technologies. This markedly improves the reliability of the PCR results by dramatically decreasing the risk of false positive results due to PCR products carryover. Moreover, using the quantitative results provided by this technique, this allows to rapidly compare the efficiency of primers, probes, and DNA extraction methods. Therefore, the hope is to identify the more specific and sensitive parameters to implement comparative studies. Automated DNA extraction should also be useful to achieve this goal. Whatever sophisticated technology is used, we still have to define the meaning of detecting nucleic acids in a given clinical sample. This seems simple in normally sterile anatomical sites but less obvious for example in respiratory specimens for invasive aspergillosis or in blood for candidosis in heavily colonized patients. Additional studies of the kinetics of fungal DNA are needed. The development of real-time technology should improve our knowledge in order to give the clinicians informative clues for making a decision. 相似文献
7.
Dissection of a metal-ion-mediated conformational change in Tetrahymena ribozyme catalysis
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Conformational changes are often required for the biological function of RNA molecules. In the Tetrahymena group I ribozyme reaction, a conformational change has been suggested to occur upon binding of the oligonucleotide substrate (S) or the guanosine nucleophile (G), leading to stronger binding of the second substrate. Recent work showed that the two substrates are bridged by a metal ion that coordinates both the nonbridging reactive phosphoryl oxygen of S and the 2'-OH of G. These results suggest that the energy from the metal ion substrate interactions is used to drive the proposed conformational change. In this work, we provide an experimental test for this model. The results provide strong support for the proposed conformational change and for a central role of the bridging metal ion in this change. The results from this work, combined with previous data, allow construction of a two-state model that quantitatively accounts for all of the observations in this and previous-work. This model provides a conceptual and quantitative framework that will facilitate understanding and further probing of the energetic and structural features of this conformational change and its role in catalysis. 相似文献
8.
N. John Wilde 《The Western journal of medicine》1953,79(3):218-219
Intraoral carcinomas first occur as primary growths. From these sites they spread by the lymphatics to the regional nodes. In the past, treatment of these lesions has consisted of radiation therapy for the primary lesion, followed by radical neck dissection. The results of this treatment have not been satisfactory. On the other hand, for carcinoma elsewhere in the body the results of surgical extirpation of the primary lesion, of the intervening lymphatics and of the regional nodes at the same operation has given much better results.In the past few years an attempt has been made to improve the results of treatment of intraoral carcinoma by removal in continuity of the primary lesion, intervening lymphatics and regional nodes. The improvement in anesthesiology, electrolytes and fluid balance, blood replacement, and the development of the antibiotics, in conjunction with the realization that the cosmetic deformity is not as great as might be expected, has led to this development. In those centers where it has been possible to apply this principle of treatment to intraoral carcinoma the results have been very encouraging. 相似文献
9.
Summary. We have developed a microagglutination test for typing rhesus monkey erythrocytes that is sensitive, accurate and easy to perform. The technique requires only μ1 quantities of antiserum and cells, and agglutination is easily detected using an inverted microscope. An advantage of this technique is that the typing plates can be stored at -70°C without loss of activity. The results of typing over 400 rhesus blood samples with this technique were 95% concordant with results using the standard microtitre agglutination technique. Preliminary results indicate that this test is also adaptable to typing human blood. 相似文献
10.
WILDE NJ 《California medicine》1953,79(3):218-219
Intraoral carcinomas first occur as primary growths. From these sites they spread by the lymphatics to the regional nodes. In the past, treatment of these lesions has consisted of radiation therapy for the primary lesion, followed by radical neck dissection. The results of this treatment have not been satisfactory. On the other hand, for carcinoma elsewhere in the body the results of surgical extirpation of the primary lesion, of the intervening lymphatics and of the regional nodes at the same operation has given much better results. In the past few years an attempt has been made to improve the results of treatment of intraoral carcinoma by removal in continuity of the primary lesion, intervening lymphatics and regional nodes. The improvement in anesthesiology, electrolytes and fluid balance, blood replacement, and the development of the antibiotics, in conjunction with the realization that the cosmetic deformity is not as great as might be expected, has led to this development. In those centers where it has been possible to apply this principle of treatment to intraoral carcinoma the results have been very encouraging. 相似文献
11.
We have developed a microagglutination test for typing rhesus monkey erythrocytes that is sensitive, accurate and easy to perform. The technique requires only microliter quantities of antiserum and cells, and agglutination is easily detected using an inverted microscope. An advantage of this technique is that the typing plates can be stored at -70 degrees C without loss of activity. The results of typing over 400 rhesus blood samples with this technique were 95% concordant with results using the standard microtitre agglutination technique. Preliminary results indicate that this test is also adaptable to typing human blood. 相似文献
12.
De-novo reverse-engineering of genome-scale regulatory networks is an increasingly important objective for biological and translational research. While many methods have been recently developed for this task, their absolute and relative performance remains poorly understood. The present study conducts a rigorous performance assessment of 32 computational methods/variants for de-novo reverse-engineering of genome-scale regulatory networks by benchmarking these methods in 15 high-quality datasets and gold-standards of experimentally verified mechanistic knowledge. The results of this study show that some methods need to be substantially improved upon, while others should be used routinely. Our results also demonstrate that several univariate methods provide a "gatekeeper" performance threshold that should be applied when method developers assess the performance of their novel multivariate algorithms. Finally, the results of this study can be used to show practical utility and to establish guidelines for everyday use of reverse-engineering algorithms, aiming towards creation of automated data-analysis protocols and software systems. 相似文献
13.
W Kędzia A Kędzia H Rajpert-Kędzia 《Folia histochemica et cytobiologica / Polish Academy of Sciences, Polish Histochemical and Cytochemical Society》2012,50(2):280-285
The main aim of this study was the analysis of undifferentiated cancers and mixed ones positive for neuroendocrine biomarkers without morphological features - typical for this type of cancer. The obtained results indicated the necessity for neuroendocrine marker tests in undifferentiated cancers and mixed ones. Immunopositive results revealed enhanced malignancy of these cancers and the necessity for additional chemotherapy. 相似文献
14.
E. Hiller K.-D. Wernecke J. Michel W. G. Chatiaschwili 《Biometrical journal. Biometrische Zeitschrift》1978,20(1):59-67
In this paper, the statistical analysis of the comprehensive data obtained from multivariable dynamic (psychophysiological) tests by means of a hybrid computing system and the results obtained are represented. Focal point is the establishment of a set of characteristics according to pertinent and statistical aspects as well as the application of the multivariate variance and discrimination analysis to this set of characteristics for the classification of given “reaction types” (RT). The discriminations carried out for the classes made visible the differences between them clearly. The physiological and possible pathophysiological significance of the results cannot be dealt with in this paper. 相似文献
15.
The bioclimatic model: a method of palaeoclimatic qualitative inference based on mammal associations
Manuel Hernández Fernández†‡ Pablo Peláez-Campomanes‡ 《Global Ecology and Biogeography》2003,12(6):507-517
Aim The bioclimatic model is a new method for palaeoclimatic reconstruction built on the assumption of a significant correlation between climate and mammal community composition. The goal of this approach is to infer past climatic conditions using mammal fossil associations as source data. Location The study used mammal faunas from all over the world to develop the bioclimatic model. As an example of the potential of the model, we have applied it to Quaternary faunas from Eurasia. Methods The proposed model was constructed by applying multivariate discriminant analysis to modern mammal faunas and climates from throughout the world. The model was validated with a different set of modern faunas than those used in the discriminant analysis, including some from transitional zones between different climates (ecotones). To test the reliability of the method in the Pleistocene, the results have been compared to those obtained with data from other disciplines, such as palaeobotany. Results The results obtained in the validation of the model show that more than 90% of the localities have been classified correctly. Comparisons of results in the late Pleistocene‐Holocene of Barová between a palaeobotanical study and the bioclimatic analysis show the latter to be highly accurate. The results for early Pleistocene faunas show somewhat drier and more open climatic conditions for Europe than the present day, with larger areas of steppe environments. Main Conclusions The bioclimatic model could be used to infer climatic conditions from mammal faunas. The results presented in this work provide a preliminary example of the potential that bioclimatic analysis has as a tool for palaeoclimatic inference. Finally, this method offers the opportunity to standardize data coming from vertebrate palaeontology for use in the construction and evaluation of climatic models. 相似文献
16.
Diatoms account for about 40% of primary production in highly productive ecosystems. The development of a new generation of fluorometers has made it possible to improve estimation of the electron transport rate from photosystem II, which, when coupled with the carbon incorporation rate enables estimation of the electrons required for carbon fixation. The aim of this study was to investigate the daily dynamics of these electron requirements as a function of the diel light cycle in three relevant diatom species and to apprehend if the method of estimating the electron transport rate can lead to different pictures of the dynamics. The results confirmed the species-dependent capacity for photoacclimation under increasing light levels. Despite daily variations in the photosynthetic parameters, the results of this study underline the low daily variability of the electron requirements estimated using functional absorption of the photosystem II compared to an estimation based on a specific absorption cross section of chlorophyll a. The stability of the electron requirements throughout the day would suggest it is potentially possible to estimate high-frequency primary production by using autonomous variable fluorescence measurements from ships-of-opportunity or moorings, without taking potential daily variation in this parameter into consideration, but this result has to be confirmed on natural phytoplankton assemblages. The results obtained in this study confirm the low electron requirements of diatoms to perform photosynthesis, and suggest a potential additional source of energy for carbon fixation, as recently described in the literature for this class. 相似文献
17.
Restoration of elbow flexion after brachial plexus injury: the role of nerve and muscle transfers 总被引:3,自引:0,他引:3
Gutowski KA Orenstein HH 《Plastic and reconstructive surgery》2000,106(6):1348-57; quiz 1358; discussion 1359
Brachial plexus trauma results in a variable loss of upper extremity function. The restoration of this function requires elbow flexion of adequate strength and range of motion. A proper evaluation of brachial plexus lesions is a prerequisite to any reconstructive procedure, and appropriate guidelines are presented. One option for restoring elbow flexion is a nerve transfer. The best results with this procedure are obtained in young patients treated within 6 months of injury. Another option is a free or pedicled muscle transfer, which should be considered in older patients or patients treated more than 6 months after an injury. Muscle transfers may also be used to augment the results of nerve transfer procedures. Choices and clinical results of donor nerves and muscle for transfer are discussed, and an algorithm for treatment is presented. 相似文献
18.
F Romano M Garancini F Uggeri L Degrate L Nespoli L Gianotti A Nespoli F Uggeri 《World journal of surgical oncology》2012,10(1):157-12
ABSTRACT: BACKGROUND: The prognosis of patients with liver metastases from gastric cancer (LMGC) is dismal, and little is known about prognostic factors in these patients; so justification for surgical resection is still controversial. Furthermore the results of chemotherapy for these patients are disappointing. The purpose of this study was to review recent outcomes of hepatectomy for LMGC and to determine the suitable candidates for surgery, assessing the surgical results and clinicopathologic features. Moreover we compare these results with those obtained with alternative treatments. 相似文献
19.
Subramanian Ganesan Shanmugarajan Anitha Alwarappan Subbiah Lakshmanan Rajendran 《The Journal of membrane biology》2013,246(6):435-442
An analysis of the reaction diffusion in a carrier-mediated transport process through a membrane is presented. A simple approximate analytical expression of concentration profiles is derived in terms of all dimensionless parameters. Furthermore, in this work we employ the homotopy perturbation method to solve the nonlinear reaction–diffusion equations. Moreover, the analytical results have been compared to the numerical simulation using the Matlab program. The simulated results are comparable with the appropriate theories. The results obtained in this work are valid for the entire solution domain. 相似文献
20.
Kim JY Oh IH Lee EY Choi KS Choe BK Yoon TY Lee CG Moon JS Shin SH Choi JM 《American journal of physical anthropology》2008,136(2):230-236
The aim of this study was to assess the secular growth changes in Korean children and adolescents during the last four decades. In 2005, 68,790 boys and 62,557 girls were recruited for this study across the nation in 2005. Anthropometric data (weight, height, etc.) were measured. We compared the results of previous nationwide growth studies with this study. The results of this survey indicate that the growth and developmental status of Korean children and adolescents has been changed substantially compared with those in 1965, 1975, 1984, and 1997. The data presented in this study show a distinct secular increase in growth in body height and weight of Korean children and adolescents spanning this period. A nationwide survey every 5 years would be beneficial to establish a reference standard for the growth of children and adolescents according to the socioeconomic, environmental, and nutritional changes. 相似文献