Capillary supply regions

The diffusion and consumption of substrate from capillaries are basic in human physiology. The general solution for the concentration in a region containing many parallel non-homogeneous capillaries is found. Except in very special cases, capillary supply regions cannot be approximated by Krogh's cylinder or Voronoi polygonal cylinders.     

Rectangular tolerance regions and multivariate normal reference regions in laboratory medicine

Reference intervals are widely used in the interpretation of results of biochemical and physiological tests of patients. When there are multiple biochemical analytes measured from each subject, a multivariate reference region is needed. Because of their greater specificity against false positives, such reference regions are more desirable than separate univariate reference intervals that disregard the cross-correlations between variables. Traditionally, under multivariate normality, reference regions have been constructed as ellipsoidal regions. This approach suffers from a major drawback: it cannot detect component-wise extreme observations. In the present work, procedures are developed to construct rectangular reference regions in the multivariate normal setup. The construction is based on the criteria for tolerance intervals. The problems addressed include the computation of a rectangular tolerance region and simultaneous tolerance intervals. Also addressed is the computation of mixed reference intervals that include both two-sided and one-sided limits, simultaneously. A parametric bootstrap approach is used in the computations, and the accuracy of the proposed methodology is assessed using estimated coverage probabilities. The problem of sample size determination is also addressed, and the results are illustrated using examples that call for the computation of reference regions.     

Argyrophilic nucleolar organizer regions

Silver staining techniques developed to demonstrate argyrophilic nucleolar organizer regions (Ag-NORs) have been widely applied in a variety of cell kinetic studies, using the mean number of AgNORs in tumour cells as a marker for malignancy of certain types of neoplasms. However, the AgNOR techniques currently available are not entirely satisfactory, as unspecific silver precipitates readily form in the sections. On the other hand, the contrast staining, may be so weak as to render identification of the AgNORs difficult. In the present study, some of the key factors influencing the outcome of AgNOR staining were evaluated in a more systematic way. A modified AgNOR staining procedure is now proposed, giving highly contrasting AgNORs with minimal unspecific silver precipitation, thus facilitating both manual and computerized counting. The new technique involves the use of microwave irradiation in order to shorten the processing time, the use of gelatin as a protective colloid, and a Farmer's solution to optimize the specificity of the technique.     

Psychrophiles and polar regions

Most reviews of microbial life in cold environments begin with a lament of how little is known about the psychrophilic (cold-loving) inhabitants or their specific adaptations to the cold. This situation is changing, as research becomes better focused by new molecular genetic (and other) approaches, by awareness of accelerated environmental change in polar regions, and by strong interest in the habitability of frozen environments elsewhere in the solar system. This review highlights recent discoveries in molecular adaptation, biodiversity and microbial dynamics in the cold, along with the concept of eutectophiles, organisms living at the critical interface inherent to the phase change of water to ice.     

Evolution of the noncoding regions inDrosophila mitochondrial DNA: Two intergenic regions

The sequences of the mitochondrial DNA (mtDNA) segment containing the two intergenic regions were determined for six species belonging to theDrosophila immigrans species group and compared to the corresponding segments ofDrosophila species which had been studied previously. We found remarkable differences in the evolutionary rates of the two intergenic regions. The Intergenic I region, which lies between thetRNA ^gln and thetRNA ^ile genes, was found to be highly conserved in terms of both size (30 ntp) and nucleotide sequence among the species studied. In contrast, the sequences of the Intergenic II region, which lies between thetRNA ^f-met and thetRNA ^ile genes, showed considerable variation. The size of the Intergenic II region ranged from 0 to 88 ntp, and accurate alignment was possible only among sequences from geographical strains or very closely related species in thenasuta species subgroup. The observed differences in conservation of the two mtDNA intergenic regions are discussed in light of functional constraints on mtDNA sequences.     

Plant adaptability in karst regions

Journal of Plant Research - Karst ecosystems are formed by dissolution of soluble rocks, usually with conspicuous landscape features, such as sharp peaks, steep slopes and deep valleys. The plants...     

Common prefrontal regions coactivate with dissociable posterior regions during controlled semantic and phonological tasks

One of the most ubiquitous findings in functional neuroimaging research is activation of left inferior prefrontal cortex (LIPC) during tasks requiring controlled semantic retrieval. Here we show that LIPC participates in the controlled retrieval of nonsemantic representations as well as semantic representations. Results also demonstrate that LIPC coactivates with dissociable posterior regions depending on the information retrieved: activating with left temporal cortex during the controlled retrieval of semantics and with left posterior frontal and parietal cortex during the controlled retrieval of phonology. Correlation of performance to LIPC activation suggests a processing role associated with mapping relatively ambiguous stimulus-to-representation relationships during both semantic and phonological tasks. These findings suggest that LIPC participates in controlled processing across multiple information domains collaborating with dissociable posterior regions depending upon the kind of information retrieved.     

Expression of chimeric receptor composed of immunoglobulin-derived V regions and T-cell receptor-derived C regions

Chimeric genes composed of immunoglobulin (Ig)-derived variable (V) regions and T-cell receptor (TCR)-derived constant (C) regions were constructed. The VL and VH genes showing anti-phosphorylcholine (PC) activity were used in this study. Two pairs of chimeric genes, VL-C beta and VH-C alpha genes, and VL-C alpha and VH-C beta genes, were inserted into an expression vector containing both Ecogpt and neo genes, and transfected into EL4 cells. Cells which express both chimeric receptor molecules were established. The activity of the transformants to the antigen was examined by using stopped-flow fluorometry. An increase in the concentration of cytoplasmic calcium ion was observed after addition of Staphylococcus pneumoniae R36A bacteria grown in the choline-containing medium which express PC molecules, but not after the PC-negative bacteria grown in the ethanolamine-containing medium.     

全球主要生态退化区和研究热点区的空间分布与演变

掌握生态退化区和研究热点区的空间分布、退化区生态系统的演变态势是认识生态问题、开展生态治理的基础,但目前缺乏全球主要生态退化区空间分布图等基础数据和相关知识。应用多源数据集成融合、长时序卫星遥感分析、互联网文献大数据建模分析等方法,对以荒漠化、水土流失、石漠化为代表的全球主要生态退化类型区的空间分布、演变态势、研究关注热度等进行了研究。结果表明：（1）全球荒漠化区面积约15.4×10⁶ km²,水土流失区面积约14.3×10⁶ km²,石漠化区面积约1.1×10⁶ km²;这些生态退化区主要分布在非洲撒哈拉沙漠南北边缘,欧洲西部、地中海沿岸、东欧平原南部,南亚印度河流域,中国西北地区、云贵高原,北美洲落基山脉以及南美洲阿根廷等地区。（2）2000年以来,上述退化区中约有3.9%的面积处于退化加重态势,73.3%的面积处于脆弱平衡状态,22.8%的区域出现好转趋势。（3）全球生态退化研究热点区的分布与全球生态退化区的分布总体呈现一致性。但在沙特阿拉伯中部、哈萨克斯坦北部,巴西大部,安哥拉、南非等生态退化区,存在生态系统继续恶化、缺乏研究界足够关注的情况。研究成果深化了对全球主要生态退化区分布格局的认识,对于防范全球发展和建设中出现加重的生态退化等具有参考价值。     

Epigenetics of specific chromosome regions

Investigation of protein complexes, various types of protein modifications and the structure of the chromatin of specific chromosome regions, such as centromeres, telomeres, and adjacent heterochromatic regions, considerably complicated the notion on DNA, prevailing five decades ago, as molecules that exclusively control coding and realization of genetic information. Striking plasticity of the primary structure of centromeric and telomeric DNA suggests a variety of molecular mechanisms underlying fundamental and universal functions of these key chromosome regions. The present review is an attempt to consider the current concepts on the structure of the DNA and protein components, as well as the structure of the chromatin of specific chromosome regions in eukaryotes, and the concerted evolution of these components, leading to the formation of a hierarchy of coordinated DNA-protein complexes.