126 research outputs found
Photothermal deflection determination of iron(II) with ferrozine with sorption preconcentration on silufol plates
Photothermal deflection spectroscopy was applied to the selective detection of iron(II) chelate with ferrozine by its sorption preconcentration on Silufol plates. The linearity range was 1 × 10-11-6 × 10 -8 mol cm-2 of chelate at the plate surface, which corresponded to 1 × 10-9 × 10-6 M of chelate in solution. The limits of detection and quantification are 8 × 10 -12 and 2.5 × 10-11 mol cm-2 at the plate from 15 μL of test solution (0.5 nM and 1.5 nM in solution, respectively), and the absolute detection limit is 8 fmol in the whole spot applied to a plate. Characteristics and features of photothermal deflection detection are discussed. © 2008 Society for Applied Spectroscopy
Delayed Hypersensitivity to Nanosecond Pulsed Electric Field in Electroporated Cells
We demonstrate that conditioning of mammalian cells by electroporation with nanosecond pulsed electric field (nsPEF) facilitates their response to the next nsPEF treatment. The experiments were designed to unambiguously separate the electroporation-induced sensitization and desensitization effects. Electroporation was achieved by bursts of 300-ns, 9 kV/cm pulses (50 Hz, n = 3–100) and quantified by propidium dye uptake within 11 min after the nsPEF exposure. We observed either sensitization to nsPEF or no change (when the conditioning was either too weak or too intense, or when the wait time after conditioning was too short). Within studied limits, conditioning never caused desensitization. With settings optimal for sensitization, the second nsPEF treatment became 2.5 times (25 °C) or even 6 times (37 °C) more effective than the same nsPEF treatment delivered without conditioning. The minimum wait time required for sensitization development was 30 s, with still longer delays increasing the effect. We show that the delayed hypersensitivity was not mediated by either cell swelling or oxidative effect of the conditioning treatment; biological mechanisms underlying the delayed electrosensitization remain to be elucidated. Optimizing nsPEF delivery protocols to induce sensitization can reduce the dose and adverse side effects of diverse medical treatments which require multiple pulse applications
The development of a toxicity database using freshwater macroinvertebrates, and its application to the protection of South African water resources
There is a growing international trend towards the protection of freshwater resources from pollution by imposing instream guidelines and specified waste-discharge conditions. Current methods for devising freshwater quality guidelines are based on species sensitivity distributions (SSDs) that are used to identify pollutant concentrations, ensuring the protection of a modelled percentage of species (95% protection is a common goal). SSDs are derived from the toxicity test results of as many taxa as possible for each polluting substance. Waste-discharge licences can be for single substances, specified in terms of chemical concentrations, and derived in conjunction with instream guidelines; or for complex mixtures, specified in terms of toxic units. In both cases toxicity test results are the core data used. The emphasis on SSDs calls into question the species constituting the test populations. It is likely that SSDs based in part on the responses of local organisms will achieve superior site-specific ecological protection. Until the early 1990s, there were very few data on the tolerances of South African freshwater organisms. In the intervening decade, the Unilever Centre for Environmental Water Quality at Rhodes University has developed a toxicity database that, to date, records the responses of 21 South African freshwater taxa to 26 single-substance pollutants or mixtures. This is the most comprehensive database of South African toxicity responses available and has been used in the drawing up of methods and guidelines to protect water resources. This paper aims to make these data available and to describe applications of the data using selected case studies
THE ROLE OF THE THIRD MISSION OF UNIVERSITIES IN SOCIAL INNOVATIONS PROMOTING
Currently, social innovation is considered as the main tool for resource mobilization to address social challenges, as a necessary element of technological innovation and socio-economic development. One of the main elements included in the concept of the "third mission" of universities
Prospects for the Bc Studies at LHCb
We discuss the motivations and perspectives for the studies of the mesons of
the (bc) family at LHCb. The description of production and decays at LHC
energies is given in details. The event yields, detection efficiencies, and
background conditions for several Bc decay modes at LHCb are estimated.Comment: 20 pages, 5 eps-figure
Two-particle decays of B_c meson into charmonium states
The factorization of hard and soft contributions into the hadronic decays of
B_c meson at large recoils is explored in order to evaluate the decay rates
into the S, P and D-wave charmonia associated with rho and pi. The constraints
of approach applicability and uncertainties of numerical estimates are
discussed. The mode with the J/psi in the final state is evaluated taking into
account the cascade radiative electromagnetic decays of excited P-wave states,
that enlarges the branching ratio by 20-25%.Comment: 13 pages, LaTeX axodraw-style, 1 figure, 2 table
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Gender differences in the pharmacological actions of pegylated glucagon-Like peptide-1 on endothelial progenitor cells and angiogenic precursor cells in a combination of metabolic disorders and lung emphysema
In clinical practice, the metabolic syndrome (MetS) is often associated with chronic obstructive pulmonary disease (COPD). Although gender differences in MetS are well documented, little is known about sex-specific differences in the pathogenesis of COPD, especially when combined with MetS. Consequently, it is not clear whether the same treatment regime has comparable efficacy in men and women diagnosed with MetS and COPD. In the present study, using sodium glutamate, lipopolysaccharide, and cigarette smoke extract, we simulated lipid metabolism disorders, obesity, hyperglycemia, and pulmonary emphysema (comorbidity) in male and female C57BL/6 mice. We assessed the gender-specific impact of lipid metabolism disorders and pulmonary emphysema on angiogenic precursor cells (endothelial progenitor cells (EPC), pericytes, vascular smooth muscle cells, cells of the lumen of the nascent vessel), as well as the biological effects of pegylated glucagon-like peptide 1 (pegGLP-1) in this experimental paradigm. Simulation of MetS/COPD comorbidity caused an accumulation of EPC (CD45−CD31+CD34+), pericytes, and vascular smooth muscle cells in the lungs of female mice. In contrast, the number of cells involved in the angiogenesis decreased in the lungs of male animals. PegGLP-1 had a positive effect on lipids and area under the curve (AUC), obesity, and prevented the development of pulmonary emphysema. The severity of these effects was stronger in males than in females. Furthermore, PegGLP-1 stimulated regeneration of pulmonary endothelium. At the same time, PegGLP-1 administration caused a mobilization of EPC (CD45−CD31+CD34+) into the bloodstream in females and migration of precursors of angiogenesis and vascular smooth muscle cells to the lungs in male animals. Gender differences in stimulatory action of pegGLP-1 on CD31+ endothelial lung cells in vitro were not observed. Based on these findings, we postulated that the cellular mechanism of in vivo regeneration of lung epithelium was at least partly gender-specific. Thus, we concluded that a pegGLP-1-based treatment regime for metabolic disorder and COPD should be further developed primarily for male patients
Leptonic constants of heavy quarkonia in potential approach of NRQCD
We consider a general scheme for calculating the leptonic constant of heavy
quarkonium QQ-bar in the framework of nonrelativistic quantum chromodynamics,
NRQCD, operating as the effective theory of nonrelativistic heavy quarks. We
explore the approach of static potential in QCD, which takes into account both
the evolution of effective charge in the three-loop approximation and the
linearly raising potential term, which provides the quark confinement. The
leptonic constants of bb-bar and cc-bar systems are evaluated by making use of
two-loop anomalous dimension for the current of nonrelativistic quarks, where
the factor for the normalization of matrix element is introduced in order to
preserve the renormalization group invariance of estimates.Comment: 18 pages, 6 eps-figures, discussion and references added, vNRQCD
analysis considere
PSYCHOLOGICAL FACTORS OF SURVIVAL AND DISEASE COURSE IN WOMEN WITH BREAST CANCER: RESULTS AND PROSPECTS OF THE STUDY
The article presents the results of a study of psychological factors of survival and the course of the disease in women with breast cancer. As a result of a longitudinal study, data were obtained on the relationship of psychological indicators with various variants of the course of the disease, as well as on the dynamics of personal and subjective characteristics with different outcomes of the disease. The authors have outlined further prospects for a longitudinal study on a sample of women with breast cancer with a fiveyear survival rate.В статье приводятся результаты исследования психологических факторов выживаемости и течения болезни у женщин с раком молочной железы. В результате лонгитюдного исследования получены данные о связи психологических показателей с различными вариантами течения болезни, а также о динамике личностных и субъектных характеристик при различных исходах болезни. Авторами обозначены дальнейшие перспективы лонгитюдного исследования на выборке женщин с раком молочной железы при пятилетней выживаемости.Исследование выполнено за счет гранта Российского научного фонда (проект № 19-18-00426)
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