627 research outputs found
Thermodynamic properties of lanthanum in gallium-indium eutectic based alloys
Activity and activity coefficients of lanthanum were determined for the first time in gallium-indium eutectic based alloys in a wide temperature range employing electromotive force method. Activity of β-La and super cooled liquid lanthanum in Ga-In eutectic based alloys between 573 and 1073 K linearly depends on the reciprocal temperature: lgaβ-La(Ga-In)=5.660-15, 352T±0.093 lgaLa(Ga-In)=6.074-15,839T±0.093 Activity coefficients of β-La and super cooled liquid lanthanum in this system at 617-1073 K are described by the following equations: lgγβ-La (Ga-In)=3.786-12,216T±0.171 lgγLa(Ga-In)=4. 199-12,703T±0.171 In addition activity of lanthanum in alloys with In was also determined in the same temperature range. © 2012 Elsevier B.V. All rights reserved
Corrosion Behavior of Modified Anodic Oxide Coatings on AD31 Aluminium Alloy
The dependences of the protective properties of the anodic oxide coatings on the AD31 aluminum alloy surface modified with nitrates of magnesium, potassium, and some 3d-elements on the composition of sealing solutions and parameters of finishing treatment were established by scanning electron microscopy, potentiodynamic polarization, electrochemical impedance spectroscopy, and salt spray chamber tests. A mechanism of the formation of modified anodic oxide coatings during sealing and subsequent thermal treating was proposed
Lowest order QED radiative corrections to five-fold differential cross section of hadron leptoproduction
The contribution of exclusive radiative tail to the cross section of
semi-inclusive hadron leptoproduction has been calculated exactly for the first
time. Although the experience of inclusive data analyses suggests us that the
contribution of radiative tail from the elastic peak is of particular
importance, similar effects in the semi-inclusive process were only recently
estimated in the peaking approximation. The explicit expressions for the lepton
part of the lowest order QED contribution of exclusive radiative tail to the
five-fold differential cross section are obtained and discussed. Numerical
estimates, provided within Jefferson Lab kinematic conditions, demonstrate
rather large effects of the exclusive radiative tail in the region at
semi-inclusive threshold and for high energy of detected hadron.Comment: 19 pages, 6 figures, 1 tabl
Measurement of the Nucleon Structure Function F2 in the Nuclear Medium and Evaluation of its Moments
We report on the measurement of inclusive electron scattering off a carbon
target performed with CLAS at Jefferson Laboratory. A combination of three
different beam energies 1.161, 2.261 and 4.461 GeV allowed us to reach an
invariant mass of the final-state hadronic system W~2.4 GeV with four-momentum
transfers Q2 ranging from 0.2 to 5 GeV2. These data, together with previous
measurements of the inclusive electron scattering off proton and deuteron,
which cover a similar continuous two-dimensional region of Q2 and Bjorken
variable x, permit the study of nuclear modifications of the nucleon structure.
By using these, as well as other world data, we evaluated the F2 structure
function and its moments. Using an OPE-based twist expansion, we studied the
Q2-evolution of the moments, obtaining a separation of the leading-twist and
the total higher-twist terms. The carbon-to-deuteron ratio of the leading-twist
contributions to the F2 moments exhibits the well known EMC effect, compatible
with that discovered previously in x-space. The total higher-twist term in the
carbon nucleus appears, although with large systematic uncertainites, to be
smaller with respect to the deuteron case for n<7, suggesting partial parton
deconfinement in nuclear matter. We speculate that the spatial extension of the
nucleon is changed when it is immersed in the nuclear medium.Comment: 37 pages, 15 figure
The HPS electromagnetic calorimeter
The Heavy Photon Search experiment (HPS) is searching for a new gauge boson, the so-called “heavy photon.” Through its kinetic mixing with the Standard Model photon, this particle could decay into an electron-positron pair. It would then be detectable as a narrow peak in the invariant mass spectrum of such pairs, or, depending on its lifetime, by a decay downstream of the production target. The HPS experiment is installed in Hall-B of Jefferson Lab. This article presents the design and performance of one of the two detectors of the experiment, the electromagnetic calorimeter, during the runs performed in 2015–2016. The calorimeter's main purpose is to provide a fast trigger and reduce the copious background from electromagnetic processes through matching with a tracking detector. The detector is a homogeneous calorimeter, made of 442 lead-tungstate (PbWO4) scintillating crystals, each read out by an avalanche photodiode coupled to a custom trans-impedance amplifier
Fatty Acids of Erythrocyte Membranes and Blood Serum in Differential Diagnosis of Inflammatory Bowel Diseases
Aim: to study fatty acid levels in erythrocyte membranes (RBC) and blood serum (BS) in patients with inflammatory bowel diseases (IBDs) to develop differential diagnostic models including fatty acids as biomarkers to distinguish between nosological entities of IBDs (ulcerative colitis — UC, Crohn's disease — CD, unclassified colitis — UCC).Materials and methods. We examined 110 patients (mean age 37,7 ± 12,1 years) with IBDs and 53 healthy patients in control group (43,3 ± 11,7 years). The IBDs group included 50 patients with UC, 41 patients with CD, 19 patients with UCC. An exacerbation of the disease was revealed in 42 patients (84 %) with UC, 34 patients with CD (82.9 %) and 11 people with UCC (57.9 %). The study of fatty acids (FA) composition of RBC membranes and BS was carried out using GC/MS system based on three Agilent 7000B quadrupoles (USA).Results. The most significant for distinguishing active UC from CD exacerbation were serum levels of elaidin (p = 0.0006); docosatetraenoic (n-6) (p = 0.004); docodienic (n-6) (p = 0.009); omega-3/omega-6 ratio (p = 0.02); docosapentaenoic (n-3) (p = 0.03); the sum of eicosapentaenoic and docosahexaenoic (p = 0.03), as well as the content of RBC lauric FA (p = 0.04) (AUC — 0.89, sensitivity — 0.91, specificity — 0.89, diagnostic accuracy — 0.91). To distinguish active UC from the same of UCC, the following serum FA were found to be significant: alpha-linolenic; saturated (pentadecanoic, palmitic, stearic, arachidic); monounsaturated (palmitoleic, oleic); omega-6 (hexadecadienic, arachidonic) (p = 0.00000011—0.03300000) (AUC — 0.995, sensitivity — 0.98, specificity — 0.96, diagnostic accuracy — 0.97). The most significant in distinguishing patients with active CD from UCC exacerbation were levels of the following FA: alpha-linolenic; palmitoleic; oleic; the amount of saturated fatty acids (SFA); total unsaturated fatty acids (UFA); stearic; monounsaturated fatty acids (MUFA) amount; SFA/UFA; SFA/PUFA (polyunsaturated fatty acids); linoleic; total PUFA n6; lauric; arachidic acid (p = 0.0000000017–0.030000000) (AUC — 0.914, sensitivity — 0.90, specificity — 0.87, diagnostic accuracy — 0.91).Conclusion. The study of FA levels in groups with different nosological forms of IBDs using complex statistical analysis, including machine learning methods, made it possible to create diagnostic models that differentiate CD, UC and UCC in the acute stage with high accuracy. The proposed approach is promising for the purposes of differential diagnosis of nosological forms of IBDs
Influence of combined transplantation of multipotent mesenchymal stromal cells and stellate liver cells on its morphofunctional state after partial hepatectomy
The aim of the study was to study the changes in the morphofunctional state of the liver after the combined transplantation of multipotent mesenchymal stromal (MMSC) and stellate liver cells (ZCP) in animals with partial hepatectomyЦелью исследования было изучение изменения морфофункционального состояния печени после проведения сочетанной трансплантации мультипотентных мезенхимальных стромальных (ММСК) и звездчатых клеток печени (ЗКП) животным с частичной гепатэктомией
Microbiome Responses to an Uncontrolled Short-Term Diet Intervention in the Frame of the Citizen Science Project
Personalized nutrition is of increasing interest to individuals actively monitoring their health. The relations between the duration of diet intervention and the effects on gut microbiota have yet to be elucidated. Here we examined the associations of short-term dietary changes, long-term dietary habits and lifestyle with gut microbiota. Stool samples from 248 citizen-science volunteers were collected before and after a self-reported 2-week personalized diet intervention, then analyzed using 16S rRNA sequencing. Considerable correlations between long-term dietary habits and gut community structure were detected. A higher intake of vegetables and fruits was associated with increased levels of butyrate-producing Clostridiales and higher community richness. A paired comparison of the metagenomes before and after the 2-week intervention showed that even a brief, uncontrolled intervention produced profound changes in community structure: resulting in decreased levels of Bacteroidaceae, Porphyromonadaceae and Rikenellaceae families and decreased alpha-diversity coupled with an increase of Methanobrevibacter, Bifidobacterium, Clostridium and butyrate-producing Lachnospiraceae- as well as the prevalence of a permatype (a bootstrapping-based variation of enterotype) associated with a higher diversity of diet. The response of microbiota to the intervention was dependent on the initial microbiota state. These findings pave the way for the development of an individualized diet.</p
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