Partition and permeation of dextran in polyacrylamide gel.

Partition of sized FITC-dextrans in polyacrylamide gel showed a relationship between Kav and solute radius as predicted by the theory of Ogston, which is based solely on geometry of the spaces. Permeability data for the same dextrans were fit to several theories, including those based on geometry and those based on hydrodynamic interactions, and the gel structure predicted by the partition and permeability data were compared. The Brinkman effective-medium model (based on hydrodynamic interactions and requiring a measure of the hydraulic conductivity of the matrix) gave the best fit of permeability data with the values for fiber radius (rf) and void volume of the gel (epsilon) that were obtained from the partition data. The models based on geometry and the hydrodynamic screening model of Cukier, using the rf and epsilon from partition data, all predicted higher rates of permeation than observed experimentally, while the effective-medium model with added term for steric interaction predicted lower permeation than that observed. The size of cylindrical pores appropriate for the partition data predicted higher rates of permeation than observed. These relative results were unaffected by the method of estimating void volume of the gel. In sum, it appears that one can use data on partition of solute, combined with measurement of hydraulic conductivity, to predict solute permeation in polyacrylamide gel.     

A haplotype-based 'haplotype relative risk' approach to detecting allelic associations.

A novel variation of the Haplotype Relative Risk (HRR) of Rubinstein et al. [Hum Immunol 1981;3:384] is proposed, in order to glean increased information about linkage disequilibrium or allelic associations by analyzing haplotype-based data rather than genotypic data. It is shown that statistical tests based on our design give much higher power than those based on the original HRR approach. Several additional nonparametric tests based on the same data are analyzed, and power is computed for each of them. Further, parametric likelihood methods are applied to testing linkage equilibrium, and estimating delta, the coefficient of linkage disequilibrium, from the same data.     

Joint surface modeling with thin-plate splines.

Mathematical joint surface models based on experimentally determined data points can be used to investigate joint characteristics such as curvature, congruency, cartilage thickness, joint contact areas, as well as to provide geometric information well suited for finite element analysis. Commonly, surface modeling methods are based on B-splines, which involve tensor products. These methods have had success; however, they are limited due to the complex organizational aspect of working with surface patches, and modeling unordered, scattered experimental data points. An alternative method for mathematical joint surface modeling is presented based on the thin-plate spline (TPS). It has the advantage that it does not involve surface patches, and can model scattered data points without experimental data preparation. An analytical surface was developed and modeled with the TPS to quantify its interpolating and smoothing characteristics. Some limitations of the TPS include discontinuity of curvature at exactly the experimental surface data points, and numerical problems dealing with data sets in excess of 2000 points. However, suggestions for overcoming these limitations are presented. Testing the TPS with real experimental data, the patellofemoral joint of a cat was measured with multistation digital photogrammetry and modeled using the TPS to determine cartilage thicknesses and surface curvature. The cartilage thickness distribution ranged between 100 to 550 microns on the patella, and 100 to 300 microns on the femur. It was found that the TPS was an effective tool for modeling joint surfaces because no preparation of the experimental data points was necessary, and the resulting unique function representing the entire surface does not involve surface patches. A detailed algorithm is presented for implementation of the TPS.     

Taxonomic congruence in Eskimoid populations.

The study compares distance relationships in Eskimoid populations based on metric and attribute data with linguistic relationships based on structural and lexicostatistical data. Taxonomic congruence and the non-specificity hypothesis are investigated by matrix correlations and by a clustering procedure. The matrix correlation approaches employed are the Pearson product-moment correlation coefficient and the Spearman rank-order correlation coefficient. An unweighted pair-group clustering procedure provides a visual comparison of biological and linguistic relationships. Data consist of 74 craniometric measurements and 28 cranial observations taken on 12 Eskimoid populations. Mahalanobis' D2 and Balakrishnan and Sanghvi's B2 were used to compute the metric and attribute distances, respectively. The results indicate that a strict adherence to the non-specificity hypothesis is untenable. Also, there is better concordance between the sexes for metric distances than for attribute distances, and the metric data are more concordant with linguistic relationships than are the attribute data.     

Phylogeny of the genus Lophozia (Dumort.) Dumort. s. str. inferred from nuclear and chloroplast sequences ITS1-2 and TRNL-F

Maximum parsimony and maximum likelihood phylogenetic trees were constructed for 21 taxa of Lophozia s. str. and the related genera, Schistochilopsis (5 species), Protolophozia elongate, and Obtusifolium obtusum based on pooled nuclear ITS 1-2 and chloroplast trnL-F DNA sequences. The trees were characterized by similar topology. It was demonstrated that the genus Lophozia s. str. was monophyletic, excluding L. sudetica, which deserved isolation into a distinct cryptic genus. The species distribution among the clades disagreed with the sections distinguished based on anatomical and morphological data. The relationships within the genus Schistochilopsis were consistent with the sectioning of the genus, based on morphological characters. Analysis of molecular data provided more precise definition of the systematic position of a number of taxa. Small genetic divergence of geographically distant forms was demonstrated.     

A dose-response model for skin cancer induction by chronic u.v. exposure of a human population

A dose-response model, based on the results of animal experiments, is presented for skin cancer induction in a human population by chronic exposure to ultraviolet radiation. The model takes into account a variety of exposure habits and susceptibilities of the individuals in the population. The required input data for the dose-response relationship are the age specific incidences of the population in question.Calculations based on this model can be used as a step in the evaluation of the effect which a reduction of stratospheric ozone would have on the non-melanoma skin cancer incidence. As an example an evaluation for the white population of the U.S.A. is presented. The estimate resulting from this evaluation agrees fairly well with earlier estimates based on combined climatological and epidemiological data.     

Optimization of batch fermentation processes. I. Development of mathematical models for batch penicillin fermentations

Two kinds of mathematical models have been developed for batch penicillin fermentations: (1) general models, based on averaged, nondimensionalized cell and penicillin synthesis curves from plant, scale fermentors and (2) particular models developed from specific sets of experimental data from two sources. Parameter-temperature functions used with the general models were assumed to have general shapes which could apply to many fermentations, i.e., they were based on the familiar temperature response of enzyme-catalyzed reactions. Parameter-temperature functions for the particular models were determined from experimental data for batch runs at various temperatures.     

The leaf anatomy of the genus Galanthus L. (Amaryllidaceae J. St.-Hil.)

The leaf anatomy of the genus Galanthus is described from transverse sections of the leaf and epidermal preparations, with the objective of identifying systematic information. Eight characters are identified as having the potential to provide data for grouping species and subspecies; six of these characters are reported here for the first time. Some of these characters, alone or in combination with other anatomical data, are useful for looking at the relationships between taxbnomically difficult species. Our results are compared with the classifications of Artjushenko, which are based on anatomical and morphological data.     

牡丹一新种——中原牡丹,及银屏牡丹的订正

分子证据和新增加的形态证据显示,银屏牡丹Paeonia suffruticosa ssp．yinpingmudan作为新亚种发表时所依据的两份标本实为两个实体,产自安徽巢湖的（潘开玉和谢中稳9701,模式）实为凤丹户P.ostii的成员,而产自河南嵩县的（洪德元等H97010）实为一个新分类群。本文把P.suffruticosa ssp．yinpingmudan处理为P．ostii的异名,并依据河南的标本描述了一个新种——中原牡丹P.cathayana D．Y Hong＆K．Y.Pan。中原牡丹与风丹和矮牡丹P.jishanensis近缘,区别在于前者下部叶有ll-15片小叶,花白色：后者小叶背面有毛,裂片多,萼片顶端圆钝,花白色。     

Synthesis,and p.m.r. and mass spectra of some boronic esters of carbohydrates

The synthesis of boronic esters of L-fucose, D-glucose, D-fructose,, and DL-glyceraldehyde is described. The structures of these compounds and appropriate derivatives, based on p.m.r. and mass-spectral data, are discussed.     

A model of thymocyte proliferation.

A steady-state model, based upon an analytical approach to the interpretation pf thymic radioautographic data is presented. In the model the process of cellular proliferation is represented by a feedback amplifier. It is shown by computer simulation that a model based on this conception, in which cellular flow through G₁ compartments is treated as a stochastic process and that through the S, G2 and M compartments by a sequential unidirectional process, is in reasonable agreement with the experimental data.     

Analysis of genetic data on Jewish populations. I. Historical background, demographic features, and genetic markers.

Part I describes the data sets on which the analysis of Part II is based. This covers the nature of the populations sampled, the extent to which the samples are representative, and a brief review of historical and demographic facts on the populations involved.     

Formats of image data files that can be used for routine digital light micrography. Part one

Failing to open computer files that describe image data is not the most frustrating experience that the user of a computer can suffer, but it is high on list of possible aggravations. To ameliorate this, the structure of uncompressed image data files is described here. The various ways in which information that describes a picture can be recorded are related, and a primary distinction between raster or bitmap based and vector or object based image data files is drawn. Bitmap based image data files are the more useful of the two formats for recording complicated images such as digital light micrographs, whereas object based files are better for recording illustrations and cartoons. Computer software for opening a very large variety of different formats of digital image data is recommended, and if these fail, ways are described for opening bitmap based digital image data files whose format is unknown.     

Formats of image data files that can be used for routine digital light micrography. Part one

Failing to open computer files that describe image data is not the most frustrating experience that the user of a computer can suffer, but it is high on list of possible aggravations. To ameliorate this, the structure of uncompressed image data files is described here. The various ways in which information that describes a picture can be recorded are related, and a primary distinction between raster or bitmap based and vector or object based image data files is drawn. Bitmap based image data files are the more useful of the two formats for recording complicated images such as digital light micrographs, whereas object based files are better for recording illustrations and cartoons. Computer software for opening a very large variety of different formats of digital image data is recommended, and if these fail, ways are described for opening bitmap based digital image data files whose format is unknown.     

Comparative virulence phenotypes and molecular genotypes of Puccinia striiformis f. sp. tritici, the wheat stripe rust pathogen in China and the United States

Stripe rust (yellow rust) of wheat, caused by Puccinia striiformis f. sp. tritici, is one of the most important diseases in both China and the United States. The Chinese and US populations of the stripe rust fungus were compared for their virulence phenotypes on wheat cultivars used to differentiate races of the pathogen in China and the US and molecular genotypes using simple sequence repeat (SSR) markers. From 86 Chinese isolates, 54 races were identified based on reactions on the 17 Chinese differentials and 52 races were identified based on the 20 US differentials. The selected 51 US isolates, representing 50 races based on the US differentials, were identified as 41 races using the Chinese differentials. A total of 132 virulence phenotypes were identified from the 137 isolates based on reactions on both Chinese and US differentials. None of the isolates from the two countries had identical virulence phenotypes on both sets of differentials. From the 137 isolates, SSR markers identified 102 genotypes, of which 71 from China and 31 from the US. The virulence data clustered the 137 isolates into 20 virulence groups (VGs) and the marker data clustered the isolates into seven molecular groups (MGs). Virulence and SSR data had a low (r = 0.34), but significant (P = 0.01) correlation. Principal component analyses using either the virulence data or the SSR data separated the isolates into three groups: group a consisting of only Chinese isolates, group b consisting of both Chinese and US isolates and group c consisting of mostly US isolates. A neighbour-joining tree generated using the molecular data suggested that the P. striiformis f. sp. tritici populations of China and the US in general evolved independently.     

Ultrasonic tissue characterization for prostate diagnostics: spectral parameters vs. texture parameters.

An ultrasonic multi-feature tissue characterizing system for the detection of prostate cancer is presented. The system is based on the processing of radio frequency (RF) ultrasonic echo data. Data from 100 patients was acquired in a clinical study. Parameters are extracted from the RF echo data and classified using two adaptive network-based fuzzy inference systems (FIS) working in parallel as a nonlinear classifier. Next to spectral parameters, conventional texture parameters are calculated using demodulated and log-compressed echo data. In the first approach, the classifier is trained on both, spectral and texture parameters. In the second approach, the classifier is only trained on texture parameters. Classification results of both approaches are compared and it is demonstrated, that only the use of spectral parameters yields satisfying classification results. Results of a minimum distance classifier (MDC) are presented for comparison with the fuzzy inference system. For the final fuzzy inference systems used in this approach, the area under the ROC curve is between 84% and 86% for the combined approach and between 70% and 74% for the approach based on texture parameters only.     

PCR-based fingerprinting using AFLPs as a tool for studying genetic relationships in Lactuca spp.

AFLP markers were evaluated for determining the phylogenetic relationships Lactuca spp. Genetic distances based on AFLP data were estimated for 44 morphologically diverse lines of cultivated L. sativa and 13 accessions of the wild species L. serriola, L. saligna, L. virosa, L. perennis, and L. indica. The same genotypes were analyzed as in a previous study that had utilized RFLP markers. The phenetic tree based on AFLP data was consistent with known taxonomic relationships and similar to a tree developed with RFLP data. The genetic distance matrices derived from AFLP and RFLP data were compared using least squares regression analysis and, for the cultivar data, by principal component analysis. There was also a positive linear relationship between distance estimates based on AFLP data and kinship coefficients calculated from pedigree data. AFLPs represent reliable PCR-based markers for studies of genetic relationships at a variety of taxonomic levels.     

1H- and 13C-n.m.r.-spectral study of synthetic methyl d-manno-oligosaccharides

¹H- and ¹³C-n.m.r. spectra for 16 synthetic methyl manno-oligosaccharides were recorded, and the signals for the anomeric protons and anomeric carbon atoms in branched manno-pentaosides and -hexaosides were assigned, based on the data for methyl manno-biosides and -triosides. These n.m.r. data identified the branching pattern of high-mannose types of glycans of glycopeptides with those of unambiguously synthesized manno-oligosaccharides, and confirmed the structures proposed for such glycans.     

Average heterozygosity revisited.

The estimate of heterozygosity and proportion of polymorphic loci for 33 red blood cell loci has been updated by the elimination of some loci of questionable status and the addition of data on 33 loci. The new figures for heterozygosity and proportion of polymorphic loci, .105 and .283, respectively, are based on 60 red blood cell loci of European origin populations. These values are less than those calculated by Lewontin in 1967, and furthermore they do not appear to be reaching an asymptote. At the present time, the red blood cell data and allozyme data for European populations have similar estimates of heterozygosity and proportion of polymorphic loci.