717 research outputs found
Application of the X-ray measurement model to image processing of X-ray radiographs
Information can be conveyed in many forms, yet it is perhaps easiest interpreted when in a visual form. The human mind has the ability to look at a scene containing complex patterns and extract particular features by considering the content of the entire image and focusing on the items of interest. The processing power, speed to decipher images, and complexity of the human brain has yet to be matched by any artificial means. Although the brain is a excellent processor and interpreter, a human can tire and become less accurate with time, potentially causing costly errors. Since consistency is especially important in inspection situations, it is desirable to automate part or all of the vision process to simplify the inspection. Thus, images can be acquired and processed to improve image quality for either human interpretation or machine perception and analysis. With image processing, it is possible to remove patterns or artifacts induced by the testing equipment, or to seek particular features for enhancement or extraction. The use of imaging technologies facilitates quantitative analysis and objective interpretation of selected parameters, especially in repetitive tasks
The Fusion-by-Diffusion model as a tool to calculate cross sections for the production of superheavy nuclei
This article summarizes recent progress in our understanding of the reaction
mechanisms leading to the formation of superheavy nuclei in cold and hot fusion
reactions. Calculations are done within the Fusion-by-Diffusion (FBD) model
using the new nuclear data tables by Jachimowicz et al. [At. Data Nucl. Data
Tables 138, 101393 (2021)]. The synthesis reaction is treated in a standard way
as a three-step process (i.e., capture, fusion, and survival). Each reaction
step is analyzed separately. Model calculations are compared with selected
experimental data on capture, fissionlike and fusion cross sections, fusion
probabilities, and evaporation residue excitation functions. The role of the
angular momentum in the fusion step is discussed in detail. A set of fusion
excitation functions with corresponding fusion probabilities is provided for
cold and hot synthesis reactions.Comment: submitted to EPJ A Topical Issue: Heavy and Super-Heavy Nuclei and
Elements: Production and Propertie
Hierarchical structure of the Sicilian goats revealed by Bayesian analyses of microsatellite information
Genetic structure and relationship amongst the main goat populations in Sicily (Girgentana, Derivata di Siria, Maltese and Messinese) were analysed using information from 19 microsatellite markers genotyped on 173 individuals. A posterior Bayesian approach implemented in the program STRUCTURE revealed a hierarchical structure with two clusters at the first level (Girgentana vs. Messinese, Derivata di Siria and Maltese), explaining 4.8% of variation (AMOVA Š¤ST estimate). Seven clusters nested within these first two clusters (further differentiations of Girgentana, Derivata di Siria and Maltese), explaining 8.5% of variation (AMOVA Š¤SC estimate). The analyses and methods applied in this study indicate their power to detect subtle population structure
Beta-lactoglobulin polymorphism in Girgentana goat breed
Beta-lactoglobulin (b-lg) is a globular protein belonging to the lipocalin family. It is the major whey protein in the
milk of ruminants. It is also present in the milk of most mammals but is lacking in rodents, lagomorphs and
humans. A large number of variants have been reported for cow and sheep milk. Several studies have shown association
between b-lg variants and milk production and composition, even if the results are not always concordant.
In goat, no b-lg variants related with amino acid change have been characterized at DNA level, but some authors
described the presence of polymorphisms in the 3āUTR and in the proximal promoter region. Mutations in the promoter
region could be those most likely responsible for different level of gene expression. The aim of this work was
to study the genetic polymorphism at DNA level of b-lg gene in Girgentana goat breed. A total of 238 genomic DNA
samples of Girgentana breed were genotyped. A fragment of 709 bp, including 588 bp of proximal promoter region
and 121 bp of exon 1, was amplified using primers GOAPF3 and GoatE1R2. PCR-RFLP procedure was used for fast
detection of two single nucleotide substitutions as described by Graziano et al. (2003). The base substitutions originating
the polymorphic sites consist of: 1. a transition TāŗC at position -341 and 2. a transition CāŗT at position -60.
A FspBI PCR-RFLP protocol was used to detect the mutation -341 (T/C) and a SmaI PCR-RFLP protocol for the
mutation -60 (C/T) of the proximal promoter region. The allelic frequencies and the Hardy-Weinberg equilibrium
were estimated using the GENEPOP software. Girgentana goat breed shows no significant deviation from Hardy-
Weinberg equilibrium for the allele frequencies found in both polymorphic sites considered. The genotypic frequencies
for both mutations resulted in 0.65 (T/T), 0.33 (T/C) and 0.02 (C/C) for the position -341, and 0.82 (C/C),
0.17 (C/T) and 0.01 (T/T) for the position -60. These results are in agreement with the previous obtained by
Graziano et al. (2003) in the same breed. Further analysis are in progress to investigate the possible effect of these
variants on the expression of b-lg gene, on the milk protein composition and on milk production traits
quantitative trait loci associated with the humoral innate immune response in chickens were confirmed in a cross between green legged partridgelike and white leghorn
Natural antibodies (NA) create a crucial barrier at the initial steps of the innate humoral immune response. The main role of NA in the defense system is to bind the pathogens at early stages of infection. Different pathogens are recognized by the presence of highly conserved antigen determinant [e. g., lipopolysaccharide (LPS) in gram-negative bacteria or lipoteichoic acid (LTA) in gram-positive bacteria]. In chickens, a different genetic background of NA binds LPS and LTA antigens, encoded by different QTL. The main objective of this work was to confirm known QTL associated with LPS and LTA NA. For this purpose a chicken reference population was created by crossing 2 breeds: a commercial layer, White Leghorn, and a Polish indigenous chicken, Green-Legged Partridgelike. The chromosomal regions analyzed harbored to GGA3, GGA5, GGA6, GGA8, GGA9, GGA10, GGA14, GGA15, GGA18, and GGAZ. The data collected consisted of the NA titers binding LPS and LTA (determined by ELISA at 12 wk of age) as well as the genotypes (30 short tandem repeat markers; average of 3 markers/chromosome, collected for generations F(0), F(1), and F(2)). The analyses were performed with 3 statistical models (paternal and maternal half-sib, line cross, and linkage analysis and linkage disequilibrium) implemented in GridQTL software (http://www.gridqtl.org.uk/). The QTL study of humoral innate immune response traits resulted in the confirmation of 3 QTL associated with NA titers binding LPS (located on GGA9, GGA18, and GGAZ) and 2 QTL associated with NA titers binding LTA (located on GGA5 and GGA14). A set of candidate genes within the regions of the validated QTL has been proposed
Crystal structure and mechanism of action of the N6-methyladenine-dependent type IIM restriction endonuclease R.DpnI.
DNA methylation-dependent restriction enzymes have many applications in genetic engineering and in the analysis of the epigenetic state of eukaryotic genomes. Nevertheless, high-resolution structures have not yet been reported, and therefore mechanisms of DNA methylation-dependent cleavage are not understood. Here, we present a biochemical analysis and high-resolution DNA co-crystal structure of the N(6)-methyladenine (m6A)-dependent restriction enzyme R.DpnI. Our data show that R.DpnI consists of an N-terminal catalytic PD-(D/E)XK domain and a C-terminal winged helix (wH) domain. Surprisingly, both domains bind DNA in a sequence- and methylation-sensitive manner. The crystal contains R.DpnI with fully methylated target DNA bound to the wH domain, but distant from the catalytic domain. Independent readout of DNA sequence and methylation by the two domains might contribute to R.DpnI specificity or could help the monomeric enzyme to cut the second strand after introducing a nick
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