188 research outputs found
Geometric Algebra Techniques for General Relativity
Geometric (Clifford) algebra provides an efficient mathematical language for
describing physical problems. We formulate general relativity in this language.
The resulting formalism combines the efficiency of differential forms with the
straightforwardness of coordinate methods. We focus our attention on
orthonormal frames and the associated connection bivector, using them to find
the Schwarzschild and Kerr solutions, along with a detailed exposition of the
Petrov types for the Weyl tensor.Comment: 34 pages, 0 figures; submitted to Annals of Physic
The Mycotoxin Deoxynivalenol Potentiates Intestinal Inflammation by Salmonella Typhimurium in Porcine Ileal Loops
Background and Aims: Both deoxynivalenol (DON) and nontyphoidal salmonellosis are emerging threats with possible hazardous effects on both human and animal health. The objective of this study was to examine whether DON at low but relevant concentrations interacts with the intestinal inflammation induced by Salmonella Typhimurium.
Methodology: By using a porcine intestinal ileal loop model, we investigated whether intake of low concentrations of DON interacts with the early intestinal inflammatory response induced by Salmonella Typhimurium.
Results: A significant higher expression of IL-12 and TNF alpha and a clear potentiation of the expression of IL-1 beta, IL-8, MCP-1 and IL-6 was seen in loops co-exposed to 1 mu g/mL of DON and Salmonella Typhimurium compared to loops exposed to Salmonella Typhimurium alone. This potentiation coincided with a significantly enhanced Salmonella invasion in and translocation over the intestinal epithelial IPEC-J2 cells, exposed to non-cytotoxic concentrations of DON for 24 h. Exposure of Salmonella Typhimurium to 0.250 mu g/mL of DON affected the bacterial gene expression level of a limited number of genes, however none of these expression changes seemed to give an explanation for the increased invasion and translocation of Salmonella Typhimurium and the potentiated inflammatory response in combination with DON.
Conclusion: These data imply that the intake of low and relevant concentrations of DON renders the intestinal epithelium more susceptible to Salmonella Typhimurium with a subsequent potentiation of the inflammatory response in the gut
A Chaperonin Subunit with Unique Structures Is Essential for Folding of a Specific Substrate
Type I chaperonins are large, double-ring complexes present in bacteria (GroEL),
mitochondria (Hsp60), and chloroplasts (Cpn60), which are involved in mediating
the folding of newly synthesized, translocated, or stress-denatured proteins. In
Escherichia coli, GroEL comprises 14 identical subunits and
has been exquisitely optimized to fold its broad range of substrates. However,
multiple Cpn60 subunits with different expression profiles have evolved in
chloroplasts. Here, we show that, in Arabidopsis thaliana, the
minor subunit Cpn60β4 forms a heterooligomeric Cpn60 complex with
Cpn60α1 and Cpn60β1–β3 and is specifically required for the
folding of NdhH, a subunit of the chloroplast NADH dehydrogenase-like complex
(NDH). Other Cpn60β subunits cannot complement the function of Cpn60β4.
Furthermore, the unique C-terminus of Cpn60β4 is required for the full
activity of the unique Cpn60 complex containing Cpn60β4 for folding of NdhH.
Our findings suggest that this unusual kind of subunit enables the Cpn60 complex
to assist the folding of some particular substrates, whereas other dominant
Cpn60 subunits maintain a housekeeping chaperonin function by facilitating the
folding of other obligate substrates
Notes for genera: basal clades of Fungi (including Aphelidiomycota, Basidiobolomycota, Blastocladiomycota, Calcarisporiellomycota, Caulochytriomycota, Chytridiomycota, Entomophthoromycota, Glomeromycota, Kickxellomycota, Monoblepharomycota, Mortierellomycota, Mucoromycota, Neocallimastigomycota, Olpidiomycota, Rozellomycota and Zoopagomycota)
Compared to the higher fungi (Dikarya), taxonomic and evolutionary studies on the basal clades of fungi are fewer in number. Thus, the generic boundaries and higher ranks in the basal clades of fungi are poorly known. Recent DNA based taxonomic studies have provided reliable and accurate information. It is therefore necessary to compile all available information since basal clades genera lack updated checklists or outlines. Recently, Tedersoo et al. (MycoKeys 13:1--20, 2016) accepted Aphelidiomycota and Rozellomycota in Fungal clade. Thus, we regard both these phyla as members in Kingdom Fungi. We accept 16 phyla in basal clades viz. Aphelidiomycota, Basidiobolomycota, Blastocladiomycota, Calcarisporiellomycota, Caulochytriomycota, Chytridiomycota, Entomophthoromycota, Glomeromycota, Kickxellomycota, Monoblepharomycota, Mortierellomycota, Mucoromycota, Neocallimastigomycota, Olpidiomycota, Rozellomycota and Zoopagomycota. Thus, 611 genera in 153 families, 43 orders and 18 classes are provided with details of classification, synonyms, life modes, distribution, recent literature and genomic data. Moreover, Catenariaceae Couch is proposed to be conserved, Cladochytriales Mozl.-Standr. is emended and the family Nephridiophagaceae is introduced
Negative ion photoelectron spectroscopy of nineteen electron organometallic complexes
The photoelectron spectra of the organometallic complexes CpCo(CO)₂⁻,
MeCpMn(CO)₃⁻ and Co₂(CO)₄(NO)₂⁻, where Cp is the cyclopentadienyl ligand (C₅H₅) and MeCp the singly methylated analogue (CH₃-C₅H₄), have been obtained using Negative Ion Photoelectron Spectroscopy (NTPES) techniques.
The experiments on CpCo(CO)₂⁻ and MeCpMn(CO)₃⁻ were performed at two
separate laser photon wavelengths, 355 and 532 run. The cobalt dimer complex was
examined only at 355 nm. Minimum vertical detachment energies for the three complexes
were found to be 0.9 ± 0.1, 0.5 ± 0.1 and 2.0 ± 0.2 eV, respectively. The bond
dissociation energy, D((CO)₃MnCpCH₂⁻-H), of one of the methyl hydrogens in the MeCpMn(CO)₃⁻ anion was found to be 2.2 ± 0.9 eV.Science, Faculty ofChemistry, Department ofGraduat
Distance Rank Score: Unsupervised filter method for feature selection on imbalanced dataset
This paper presents a new filter method for unsupervised feature selection. This method is particularly effective on imbalanced multi-class dataset, as in case of clusters of different anomaly types. Existing methods usually involve the variance of the features, which is not suitable when the different types of observations are not represented equally. Our method, based on Spearman's Rank Correlation between distances on the observations and on feature values, avoids this drawback. The performance of the method is measured on several clustering problems and is compared with existing filter methods suitable for unsupervised data
Explainable multi-class anomaly detection on functional data
In this paper we describe an approach for anomaly detection and its
explainability in multivariate functional data. The anomaly detection procedure
consists of transforming the series into a vector of features and using an
Isolation forest algorithm. The explainable procedure is based on the
computation of the SHAP coefficients and on the use of a supervised decision
tree. We apply it on simulated data to measure the performance of our method
and on real data coming from industry
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