scholarly journals Material Geometry of Binary Composites

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 892
Author(s):  
Marcelo Epstein

The constitutive characterization of the uniformity and homogeneity of binary elastic composites is presented in terms of a combination of the material groupoids of the individual constituents. The incorporation of these two groupoids within a single double groupoid is proposed as a viable mathematical framework for a unified formulation of this and similar kinds of problems in continuum mechanics.

1981 ◽  
Vol 64 (4) ◽  
pp. 875-883
Author(s):  
Shiv K Soni ◽  
Daniel Van Gelder

Abstract Due to the existence of 2 asymmetric carbon atoms in: the propoxyphene molecule, there are 4 diastereomers: alpha dextro, alpha levo, beta dextro, and beta levo. Only α-d-propoxyphene is included under the federal Controlled Substances Act. Baseline separations of propoxyphene from various incipients (aspirin, caffeine, phenacetin, and acetaminophen) present in pharmaceutical and illicit preparations, and between the alpha and beta diastereomers, were achieved by high pressure liquid chromatography. The column eluant was collected and propoxyphene was extracted. The optical isomers were differentiated and characterized by melting points and by chemical microcrystalline tests. Using hot stage thermomicroscopy, the eutectic melting points of binary isomeric mixtures of propoxyphene bases and salts were found to be depressed about 10° and 15-30°C, respectively, below the individual isomer melting points. The characteristic microcrystals formed with the alpha racemic mixtures by using a glycerin-aqueous gold chloride reagent were not produced by the beta racemic mixtures.


2021 ◽  
pp. 1-13
Author(s):  
Lamiae Benhayoun ◽  
Daniel Lang

BACKGROUND: The renewed advent of Artificial Intelligence (AI) is inducing profound changes in the classic categories of technology professions and is creating the need for new specific skills. OBJECTIVE: Identify the gaps in terms of skills between academic training on AI in French engineering and Business Schools, and the requirements of the labour market. METHOD: Extraction of AI training contents from the schools’ websites and scraping of a job advertisements’ website. Then, analysis based on a text mining approach with a Python code for Natural Language Processing. RESULTS: Categorization of occupations related to AI. Characterization of three classes of skills for the AI market: Technical, Soft and Interdisciplinary. Skills’ gaps concern some professional certifications and the mastery of specific tools, research abilities, and awareness of ethical and regulatory dimensions of AI. CONCLUSIONS: A deep analysis using algorithms for Natural Language Processing. Results that provide a better understanding of the AI capability components at the individual and the organizational levels. A study that can help shape educational programs to respond to the AI market requirements.


Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4221
Author(s):  
Aage Kristian Olsen Alstrup ◽  
Svend Borup Jensen ◽  
Ole Lerberg Nielsen ◽  
Lars Jødal ◽  
Pia Afzelius

The development of new and better radioactive tracers capable of detecting and characterizing osteomyelitis is an ongoing process, mainly because available tracers lack selectivity towards osteomyelitis. An integrated part of developing new tracers is the performance of in vivo tests using appropriate animal models. The available animal models for osteomyelitis are also far from ideal. Therefore, developing improved animal osteomyelitis models is as important as developing new radioactive tracers. We recently published a review on radioactive tracers. In this review, we only present and discuss osteomyelitis models. Three ethical aspects (3R) are essential when exposing experimental animals to infections. Thus, we should perform experiments in vitro rather than in vivo (Replacement), use as few animals as possible (Reduction), and impose as little pain on the animal as possible (Refinement). The gain for humans should by far exceed the disadvantages for the individual experimental animal. To this end, the translational value of animal experiments is crucial. We therefore need a robust and well-characterized animal model to evaluate new osteomyelitis tracers to be sure that unpredicted variation in the animal model does not lead to a misinterpretation of the tracer behavior. In this review, we focus on how the development of radioactive tracers relies heavily on the selection of a reliable animal model, and we base the discussions on our own experience with a porcine model.


Blood ◽  
1988 ◽  
Vol 72 (2) ◽  
pp. 636-641 ◽  
Author(s):  
R Anand ◽  
CD Boehm ◽  
HH Jr Kazazian ◽  
EF Vanin

Abstract We report the characterization of a beta zero-thalassemia in an American Black with unusually high HbA2 and HbF levels. Genomic southern analysis indicated that the individual was heterozygous for a deletion that began within the second intervening sequence of the beta- globin gene and extended approximately 1.4 kb in the 5′ direction. A clone spanning the breakpoint on the abnormal chromosome was isolated and further mapped, and the deletion joint was sequenced. Comparison of the normal beta-globin gene and its 5′ flanking region with the deletion joint sequence indicated that the 5′ breakpoint for this deletion was 484 base pairs (bp) 5′ to the transcriptional start site for the beta-globin gene and the 3′ breakpoint was 908 bp into the beta- globin gene; the deletion removed a total of 1,393 bp. Comparison of the normal 5′ and 3′ breakpoint sequences indicated that this deletion was the result of a “clean” nonhomologous breakage and reunion event; ie, no spurious bases were added during the recombinational event. Analysis of the breakpoints of this deletion together with the breakpoints of two other small deletions involving the beta-globin gene suggests that the breakpoints may occur at DNA polymerase alpha pause sites.


Genome ◽  
2006 ◽  
Vol 49 (12) ◽  
pp. 1545-1554 ◽  
Author(s):  
J. Li ◽  
D.L. Klindworth ◽  
F. Shireen ◽  
X. Cai ◽  
J. Hu ◽  
...  

The aneuploid stocks of durum wheat ( Triticum turgidum L. subsp. durum (Desf.) Husnot) and common wheat ( T. aestivum L.) have been developed mainly in ‘Langdon’ (LDN) and ‘Chinese Spring’ (CS) cultivars, respectively. The LDN-CS D-genome chromosome disomic substitution (LDN-DS) lines, where a pair of CS D-genome chromosomes substitute for a corresponding homoeologous A- or B-genome chromosome pair of LDN, have been widely used to determine the chromosomal locations of genes in tetraploid wheat. The LDN-DS lines were originally developed by crossing CS nulli-tetrasomics with LDN, followed by 6 backcrosses with LDN. They have subsequently been improved with 5 additional backcrosses with LDN. The objectives of this study were to characterize a set of the 14 most recent LDN-DS lines and to develop chromosome-specific markers, using the newly developed TRAP (target region amplification polymorphism)-marker technique. A total of 307 polymorphic DNA fragments were amplified from LDN and CS, and 302 of them were assigned to individual chromosomes. Most of the markers (95.5%) were present on a single chromosome as chromosome-specific markers, but 4.5% of the markers mapped to 2 or more chromosomes. The number of markers per chromosome varied, from a low of 10 (chromosomes 1A and 6D) to a high of 24 (chromosome 3A). There was an average of 16.6, 16.6, and 15.9 markers per chromosome assigned to the A-, B-, and D-genome chromosomes, respectively, suggesting that TRAP markers were detected at a nearly equal frequency on the 3 genomes. A comparison of the source of the expressed sequence tags (ESTs), used to derive the fixed primers, with the chromosomal location of markers revealed that 15.5% of the TRAP markers were located on the same chromosomes as the ESTs used to generate the fixed primers. A fixed primer designed from an EST mapped on a chromosome or a homoeologous group amplified at least 1 fragment specific to that chromosome or group, suggesting that the fixed primers might generate markers from target regions. TRAP-marker analysis verified the retention of at least 13 pairs of A- or B-genome chromosomes from LDN and 1 pair of D-genome chromosomes from CS in each of the LDN-DS lines. The chromosome-specific markers developed in this study provide an identity for each of the chromosomes, and they will facilitate molecular and genetic characterization of the individual chromosomes, including genetic mapping and gene identification.


2002 ◽  
Vol 22 (2) ◽  
pp. 536-546 ◽  
Author(s):  
Qin Feng ◽  
Ru Cao ◽  
Li Xia ◽  
Hediye Erdjument-Bromage ◽  
Paul Tempst ◽  
...  

ABSTRACT Methylation of cytosine at CpG dinucleotides is a common feature of many higher eukaryotic genomes. A major biological consequence of DNA methylation is gene silencing. Increasing evidence indicates that recruitment of histone deacetylase complexes by methyl-CpG-binding proteins is a major mechanism of methylated DNA silencing. We have previously reported that the MeCP1 protein complex represses transcription through preferential binding, remodeling, and deacetylation of methylated nucleosomes. To understand the molecular mechanism of the functioning of the MeCP1 complex, the individual components of the MeCP1 complex need to be characterized. In this paper, we report the identification and functional characterization of the p66 and p68 components of the MeCP1 complex. We provide evidence that the two components are different forms of the same zinc finger-containing protein. Analysis of the p66 homologs from different organisms revealed two highly conserved regions, CR1 and CR2. While CR1 is involved in the association of p66 with other MeCP1 components, CR2 plays an important role in targeting p66 and MBD3 to specific loci. Thus, our study not only completes the identification of the MeCP1 components but also reveals the potential function of p66 in MeCP1 complex targeting. The identification and characterization of all the MeCP1 components set the stage for reconstitution of the MeCP1 complex.


2013 ◽  
Vol 205-206 ◽  
pp. 284-289 ◽  
Author(s):  
David Lysáček ◽  
Petr Kostelník ◽  
Petr Pánek

We report on a novel method of low pressure chemical vapor deposition of polycrystalline silicon layers used for external gettering in silicon substrate for semiconductor applications. The proposed method allowed us to produce layers of polycrystalline silicon with pre-determined residual stress. The method is based on the deposition of a multilayer system formed by two layers. The first layer is intentionally designed to have tensile stress while the second layer has compressive stress. Opposite sign of the residual stresses of the individual layers enables to pre-determine the residual stress of the gettering stack. We used scanning electron microscopy for structural characterization of the layers and intentional contamination for demonstration of the gettering properties. Residual stress of the layers was calculated from the wafer curvature.


Author(s):  
Gabor Simko ◽  
Tihamer Levendovszky ◽  
Sandeep Neema ◽  
Ethan Jackson ◽  
Ted Bapty ◽  
...  

One of the primary goals of the Adaptive Vehicle Make (AVM) program of DARPA is the construction of a model-based design flow and tool chain, META, that will provide significant productivity increase in the development of complex cyber-physical systems. In model-based design, modeling languages and their underlying semantics play fundamental role in achieving compositionality. A significant challenge in the META design flow is the heterogeneity of the design space. This challenge is compounded by the need for rapidly evolving the design flow and the suite of modeling languages supporting it. Heterogeneity of models and modeling languages is addressed by the development of a model integration language – CyPhy – supporting constructs needed for modeling the interactions among different modeling domains. CyPhy targets simplicity: only those abstractions are imported from the individual modeling domains to CyPhy that are required for expressing relationships across sub-domains. This “semantic interface” between CyPhy and the modeling domains is formally defined, evolved as needed and verified for essential properties (such as well-formedness and invariance). Due to the need for rapid evolvability, defining semantics for CyPhy is not a “one-shot” activity; updates, revisions and extensions are ongoing and their correctness has significant implications on the overall consistency of the META tool chain. The focus of this paper is the methods and tools used for this purpose: the META Semantic Backplane. The Semantic Backplane is based on a mathematical framework provided by term algebra and logics, incorporates a tool suite for specifying, validating and using formal structural and behavioral semantics of modeling languages, and includes a library of metamodels and specifications of model transformations.


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