19,442 research outputs found
On unitary convex decompositions of vectors in a -algebra
No full textsummary:By exploiting his recent results, the author further investigates the extent to which variation in the coefficients of a unitary convex decomposition of a vector in a unital -algebra permits the vector decomposable as convex combination of fewer unitaries; certain -algebra results due to M. Rørdam have been extended to the general setting of -algebras
An investigation into the performance and problems of first-year engineering students at the University of Cape Town
No full textBibliography: leaves 203-208.The first- and second-year results of the 1989 engineering student intake were analysed and revealed that matriculants from Black Education Departments performed significantly worse in the first year than those from White Education Departments. Matric point scores were found to be good predictors for White Education Department matriculants, but less so for Black Education Department matriculants, with matric Physical Science a better predictor than matric Maths, for both first- and second- year courses. Using interviews and a survey of students, a set of academic and non-academic problems experienced by first-year engineering students were identified with black students found to have experienced a particular set of problems to a greater degree than white students. The data produced a portrait of the interaction between first-year engineering students and the academic and social systems of the university. The dominant feature that emerged was one of distance between the individual students and elements of the university environment, including staff, fellow students and the academic material. Factors from the student's personal and educational background that appeared to accentuate this experience of distance were identified. Recommendations to the Engineering Faculty were compiled on the basis of this analysis together with student suggestions for improving the first-year engineering programme
Linear Preserves of BP-quasi invertible elements in JB*-algebras
No full textIn this note, we study one of the main outcomes of the Russo-Dye Theorem of JB*-algebra: a linear operator that preserves Brown-Pedersen-quasi invertible elements between two JB*-algebras is characterized by a Jordan ∗-homomorphism. Earlier, in C*-setting of algebras, Russo and Dye gave a characterization of any linear operator that maps unitary elements into unitary elements; namely a Jordan ∗-homomorphism. Special sorts of linear preservers between C*-algebras and between JB*-triples were introduced by Burgos et al. As a result, if G is a linear operator between two JB*-algebras having non-empty sets of extreme points of the closed unit sphere that preserves extreme points, then there exists a Jordan ∗-homomorphism Φ which also preserves extreme points and characterizes the linear operator G. We also explore the connection between linear operators that strongly preserve Brown-Pedersen-quasi nvertible elements between two JB*-triples and the λ-property of both JB*-triples. Other geometric properties, such as extremally richness and the Bade property of two JB*-algebras or triples under linear preservers, are to be elaborated on in forthcoming research
Erratum: Half-supersymmetric solutions in five-dimensional supergravity (Journal of High Energy Physics (2007) 12 (025))
No full text[No abstract available]Gutowski JB, 2007, J HIGH ENERGY PHYS11
Comparative analysis of paraffin and JB-4 embedding techniques in light microscopy
No full textHistological embedding and staining techniques are essential for examining tissue and cellular morphology. This study compares two embedding methods - JB-4™, a glycol methacrylate-based resin, and conventional paraffin - to determine which method provides superior visualization of liver and long bone tissues under light microscopy. Liver tissues from both embedding protocols were stained using the Periodic Acid-Schiff method and silver impregnation method. JB-4 sections were also stained with acid fuchsin and toluidine blue, while paraffin sections were stained with hematoxylin and eosin staining. Contrary to the common assumption that JB-4 may interferes with certain staining protocols, acid fuchsin and toluidine blue yielded high-contrast, structurally detailed results in JB-4 sections. Both techniques preserved liver morphology. However, JB-4 demonstrated higher resolution and enhanced visualization of intracellular structures. JB4 also preservedglycogen more effectively. Cellular structures including nuclei, nucleoli, bile duct epithelial cells, and Kupffer cells, were observedmore distinctly in JB-4 preparations. Reticular fibers were similarly visualized with both embedding techniques. In contrast, paraffin embedding provided better preserved overall tissue architecture. Whilelong bone specimens, paraffin sections frequently displayed poorly defined structures, while JB-4 offered clearer visualization of chondrocyte lacunae, osteocyte nuclei, lamellar bone, and bone marrow cells. JB-4 and paraffin each offer distinct advantages depending on tissue type and histological objective. JB-4 appears to be compatible with a broader range of stains than was previously reported, which expands its utility in detailed tissue analysis. The selection of an embedding method should align with the morphological characteristics of the target tissue and the specific research goals
HO-1 expression is enhanced in Dendritic cells assocaited with JB-1.
No full text<p>Dendritic cells were cultured from bone marrow and CD11c+ cells isolated and cocultured with PKH26 labeled <i>L.rhamnosus</i> JB-1 for 24 hr and HO-1 expression assessed by FACS. A) A dot plot showing a subpopulation of dendritic cells associated with the labeled lactobacillus. This is representative of 4 similar experiments. B) Representative dot plots and C) mean values of the percentage HO-1+ cells in the Lactobacillus associated (JB-1+ve) and non-associated (JB-1-ve) dendritic cell populations. Evidence for in vivo interaction between DC and JB-1 is provided by D) Representative dot plots and E) mean values of CFSE positive cells within the CD11c positive population from Peyers Patches of mice fed with CFSE labeled or unlabeled JB-1. Data presented as mean ± SEM, n = 5, *p<0.05. CFSE = carboxyfluorescein diacetate succinimidyl ester.</p
Surjective isometries between unitary sets of unital JB∗-algebras
No full textWe would like to thank Prof. Lajos Molnár for encouraging us to explore this problem.
We are also indebted to the anonymous reviewer for several useful comments.
First and fifth authors partially supported by the Spanish Ministry of Science, Innovation and Universities (MICINN) and European Regional Development Fund project
no. PGC2018-093332-B-I00, Programa Operativo FEDER 2014-2020 and Consejería de
Economía y Conocimiento de la Junta de Andalucía grant numbers A-FQM-242-UGR18
and FQM375. First author partially supported by EPSRC (UK) project “Jordan Algebras, Finsler Geometry and Dynamics” ref. no. EP/R044228/1. Second author partially
supported by JSPS KAKENHI Grant Number JP 21J21512. Fourth author partially
supported by JSPS KAKENHI (Japan) Grant Number JP 20K03650.
* Funding for open access charge: Universidad de Granada / CBUAThis paper is, in a first stage, devoted to establishing a topological–algebraic characterization of the principal component, U0(M), of the set of unitary elements, U(M), in a unital JB⁎-algebra M. We arrive to the conclusion that, as in the case of unital C⁎-algebras, U0(M)=M1−1∩U(M)={Ue⋯Ue(1):n∈N,hj∈Msa∀1≤j≤n}={u∈U(M): there exists w∈U0(M) with ‖u−w‖<2} is analytically arcwise connected. Actually, U0(M) is the smallest quadratic subset of U(M) containing the set eiM. Our second goal is to provide a complete description of the surjective isometries between the principal components of two unital JB⁎-algebras M and N. Contrary to the case of unital C⁎-algebras, we shall deduce the existence of connected components in U(M) which are not isometric as metric spaces. We shall also establish necessary and sufficient conditions to guarantee that a surjective isometry Δ:U(M)→U(N) admits an extension to a surjective linear isometry between M and N, a conclusion which is not always true. Among the consequences it is proved that M and N are Jordan ⁎-isomorphic if, and only if, their principal components are isometric as metric spaces if, and only if, there exists a surjective isometry Δ:U(M)→U(N) mapping the unit of M to an element in U0(N). These results provide an extension to the setting of unital JB⁎-algebras of the results obtained by O. Hatori for unital C⁎-algebras.CBUAConsejería de Economía y Conocimiento de la Junta de Andalucía
A-FQM-242-UGR18, FQM375Ministerio de Ciencia, Innovación y UniversidadesEngineering and Physical Sciences Research Council
EP/R044228/1Universidad de GranadaMinisterio de Ciencia e InnovaciónJapan Society for the Promotion of Science JP 20K03650, JP 21J21512European Regional Development Fund
PGC2018-093332-B-I0
<i>Lb</i>. <i>rhamnosus</i> JB-1 internalisation by MDDCs.
No full text<p>(A) Following antibiotic treatment, which kills bacteria outside MDDCs, the peak recovery of viable <i>Lb</i>. <i>rhamnosus</i> JB-1 was observed after 48 hours, suggesting that this was the time point when the bacteria were internalized by the MDDCs. (B) MDDC phagocytosis of another bacterial strain, <i>E</i>. <i>coli</i>, was reduced when the MDDCs were co-exposed to <i>Lb</i>. <i>rhamnosus</i> JB-1, but not <i>Lb</i>. <i>murinus</i>.</p
CHARACTERIZATION AND QUANTIFICATION OF ENDOGENOUS PHAGES OF LACTICASEIBACILLUS RHAMNOSUS JB-1
No full textLacticaseibacillus rhamnosus JB-1 is a strain recognized for its beneficial effects on eukaryotic host. This study aims to identify and characterize dormant bacterial viruses or prophages with the JB-1 genome, determine their capacity to be released as bacteriophages. We also investigate the membrane vesicles released from JB-1 and detect bacteriophages within these preparations. Bioinformatic analysis of the JB-1 genome predicted the presence of three prophage regions. Experimental validation demonstrated spontaneous release of two of these phages, which were also detected along with membrane vesicles and found systemically circulating. Genomic characterization included sequence annotation, determination of exact start/end points, analysis of gene function and comparison with other related bacteriophages. The JB-1 CRISPR-Cas system was also identified and characterized which will contribute to a deeper understanding of the potential for future manipulation of this probiotic microorganism. Morphological characterization was conducted using transmission electron microscopy to determine capsid shape, size, tail length, to classify the phages based on these features. To overcome limitations in quantifying phages lacking suitable hosts for propagation, a qPCR-based method was developed and validated. Furthermore, the stability of JB-1 phages was studied under a range of temperature and pH conditions relevant to the gastrointestinal tract.ThesisMaster of Science (MSc)The human digestive system is home to trillions of bacteria, collectively known as the gut microbiota, which play a pivotal role in our health. Probiotics, which are ‘good bacteria’, are live microorganisms that can provide health benefits when consumed. One such microorganism is Lacticaseibacillus rhamnosus JB-1, known for its beneficial effects in mice. In this study, we investigate the presence of dormant bacteriophages integrated within the JB-1 genome and genomically characterize it. We confirm that some of these viral blueprints can be induced as phages. This raises questions to how probiotics might exert their beneficial effects and highlights the importance of understanding bacteriophages associated with probiotic microorganisms. Additionally, JB-1 bacteriophages do not have a suitable host to propagate, so we study the potential of qPCR as a tool to quantify the phages. We investigated the stability of JB-1 phages to temperature and pH conditions relevant to the gastric environment, using qPCR. This study also highlights the use of qPCR for the quantification of phages lacking a host to propagate and provides valuable insights into the stability of JB-1 bacteriophages under conditions relevant to their passage through the host, which are crucial considerations for understanding their potential impact within the gastrointestinal environment
Pharmacological, neurochemical, and behavioral profile of JB-788, a new 5-HT1A agonist
No full textInternational audienceA novel pyridine derivative, 8-4-[(6-methoxy-2,3-dihydro-[1,4]dioxino[2,3-b]pyridine-3-ylmethyl)-amino]-butyl -8-aza-spiro[4.5]decane-7,9-dione hydrochloride, termed JB-788, was designed to selectively target 5-HT(1A) receptors. In the present study, the pharmacological profile of JB-788 was characterized in vitro using radioligands binding tests and in vivo using neurochemical and behavioural experiments. JB-788 bound tightly to human 5-HT(1A) receptor expressed in human embryonic kidney 293 (HEK-293) cells with a K(i) value of 0.8 nM. Its binding affinity is in the same range as that observed for the (+/-)8-OH-DPAT, a reference 5HT(1A) agonist compound. Notably, JB-788 only bound weakly to 5-HT(1B) or 5-HT(2A) receptors and moreover the drug displayed only weak or indetectable binding to muscarinic, alpha(2), beta(1) and beta(2) adrenergic receptors, or dopaminergic D(1) receptors. JB-788 was found to display substantial binding affinity for dopaminergic D(2) receptors and, to a lesser extend to alpha(1) adrenoreceptors. JB-788 dose-dependently decreased forskolin-induced cAMP accumulation in HEK cells expressing human 5-HT(1A), thus acting as a potent 5-HT(1A) receptor agonist (E(max.) 75%, EC(50) 3.5 nM). JB-788 did not exhibit any D(2) receptor agonism but progressively inhibited the effects of quinpirole, a D(2) receptor agonist, in the cAMP accumulation test with a K(i) value of 250 nM. JB-788 induced a weak change in cAMP levels in mouse brain but, like some antipsychotics, transiently increased glycogen contents in various brain regions. Behavioral effects were investigated in mice using the elevated plus-maze. JB-788 was found to increase the time duration spent by animals in anxiogenic situations. Locomotor hyperactivity induced by methamphetamine in mouse, a model of antipsychotic activity, was dose-dependently inhibited by JB-788. Altogether, these results suggest that JB-788 displays pharmacological properties, which could be of interest in the area of anxiolytic and antipsychotic drugs
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