262 research outputs found
Asymptotic exchange coupling of quasi-1D excitons in carbon nanotubes
An analytical expression is obtained for the biexciton binding energy as a
function of the inter-exciton distance and binding energy of constituent
quasi-one-dimensional excitons in carbon nanotubes. This allows one to trace
biexciton energy variation and relevant non-linear absorption under external
conditions whereby the exciton binding energy varies. The non-linear absorption
lineshapes calculated exhibit characteristic asymmetric (Rabi) splitting as the
exciton energy is tuned to the nearest interband plasmon resonance. These
results are useful for tunable optoelectronic device applications of optically
excited semiconducting carbon nanotubes, including the strong excitation regime
with optical non-linearities.Comment: 4 pages, 3 figures. Text and figures updated. References adde
Evolving spectrum of arrhythmogenic cardiomyopathy: Implications for Sports Cardiology
Arrhythmogenic cardiomyopathy (ACM) is a genetic heart muscle disease, structurally characterized by progressive fibro-fatty replacement of the normal myocardium and clinically by ventricular arrhythmias (VAs). Predominantly thanks to the use of cardiac magnetic resonance, we have learnt that the spectrum of the disease encompasses not only the classical right ventricular phenotype, but also biventricular and left dominant variants. Sport activity contributes to the phenotypic expression and progression of ACM and may trigger life-threatening VAs and sudden cardiac death (SCD). We conducted a review of the literature about ACM and its implications in Sport Cardiology and summarized the main findings in this topic. Early identification of affected athletes through preparticipation screening (PPS) is fundamental but, while classical right-ventricular or biventricular phenotypes are usually suspected because of electrocardiogram (ECG) and echocardiographic abnormalities, variants with predominant left ventricular involvement are often characterized by normal ECG and unremarkable echocardiography. Usually the only manifestations of such variants are exercise-induced VAs and for this reason exercise testing may empower the diagnostic yield of the PPS. Patients with ACM are not eligible to competitive sports activity, but low-to-moderate intensity physical activity under medical supervision is possible in most cases
Effects of temperature patterns on the spawining phenology and niche overlap of fish assemblages in the water bodies of the Dnipro River basin
The effect of the temperature on the spawining phenology of the fish assemblages and the role of the exogenious and
endogenious factors in temporal niche overlaping of fish assemblages were investigated in different water body types of the Dnipro River basin within the “Dnipro-Orilskiy" Nature Reserve (Ukraine in the years 1997-2018. The period of spawning (beginning and end) of the Blicca bjoerkna, Carassius gibelio, Scardinius erythrophthalmus, Abramis brama,Perca fluviatilis, Rutilus rutilus, and Esox lucius was estimated. Community niche overlap was estimated by calculating
the pairwise Pianka index. The temperature was discused as an exogenous factor effecting on the fishes spawn timing.
From 1998 to 2018 the average temperature in the study area continued to rise. The annual course of the temperature
takes the sinusoidal waveform, which can be described by a fourth-degree polynomial. The residuals of the
corresponding polynomial trend are specific for each year. The regular components of the residuals variation were
revealed by dbMEM-variables. Fishes spawning occurred within the narrow water temperature ranges, which are
specific for each fish species. There are statistically significant differences between ponds in water temperatures at
which the spawning start occurred. The water temperature at which the spawning start occurred is linearly dependent on
the time of the spawning start. There were temporal overlaps between spawning of the different species. The deviation
of the Pianka mean niche overlap indexes from random alternatives does not depend on the habitat type. The decreasing
trend of the Pianka mean niche overlap indexes was observed during the study period. There is no statistically
significant correlation between the average annual air temperature and the level of the niche overlap. The degree of
niche overlapping depends on broad-, medium-, and fine-scale temperature patterns
Aspects and issues of marketing authorisation and use of medicinal products for COVID-19 prevention during the pandemic
At the end of 2019, an outbreak of a new coronavirus began in the city of Wuhan (Hubei Province) in the People's Republic of China. The outbreak turned into a pandemic. In the shortest possible time, national and international manufacturers developed preventive COVID-19 vaccines, and the population was vaccinated. During pandemics, accelerated approval of vaccines is an important factor that shortens the time to market with the aim of mass vaccination. The experience of rapidly developing and introducing vaccines into routine practice is not only important for managing the current pandemic, but also valuable in case of extremely likely future ones. The aim of this study was to analyse the main issues associated with assessing the safety and efficacy of vaccines for COVID-19 prevention during their registration and widespread use amid the pandemic and ongoing SARS-CoV-2 evolution. The vaccines for COVID-19 prevention were developed and introduced into healthcare practice very rapidly and under the circumstances of the pandemic, and the use of these vaccines has surfaced a number of concerns requiring further research. The most important issues identified in the performed analysis include, but are not limited to the need for accelerated assessment of the safety and immunogenicity of new vaccines; the lack of immune correlates of protection against SARS-CoV-2; the waning of antibody immunity over time, motivating the need to determine revaccination and post-recovery vaccination timelines; and the emergence of mutant SARS-CoV-2 variants. One of noteworthy aspects is the need to develop recommendations for updating the strain composition of registered COVID-19 vaccines. According to the conclusions, the level of herd immunity, including vaccine-induced protection, plays a certain role in virus evolution during the pandemic. If COVID-19 becomes seasonal, which is a probable scenario, regular revaccination can be essential
The impact of temporal patterns of temperature and precipitation on silver Prussian carp (Carassius gibelio) spawning events
It was revealed that Gibel carp, Carassius gibelio (Bloch, 1782) spawning phenology is determined by regular patterns of variability in temperature and precipitation over the period of time after spawning in the previous year. The sensitivity to temperature of water as a stimulus to spawning was shown as being dependent on the characteristics of the environment and fish development trajectories over the previous year. Information about fish spawning was collected in the Dnipro-Orylskiy Nature Reserve in the following locations: Nikolayev system of water bodies, River Protoch system and the Obukhov floodplain, the channel of the River Dnipro, water bodies of the Taromske ledge. The materials that formed the basis of this research were collected from the waters of the reserve in the years 1997–2018. There are dependencies between the air and water temperatures that have their own characteristics depending on the type of water body. These dependencies are described by a logistic equation. The temperature regime in water bodies of the Taromske ledge is very similar to the temperature regime of Nikolayev system of water bodies. The difference is that the spring period of the temperature increase in water bodies of the Taromske ledge comes earlier – in late February – early March. The air temperature dynamics over the year is described by the fourth degree polynomial. The residuals of the polynomial regression for each year were subjected to principal component analysis. The principal component analysis allowed us to identify 8 principal components of the temperature regimes, which together describe 59.2% of the variation of the residual of the polynomial trend. Deviations from the linear trend of the precipitation are systematic throughout the year, reflecting the uneven nature of rainfall during the year. The residuals of linear trend regression models of cumulative precipitation can be used as indicators of the dynamics characteristic of precipitation during the year. The residuals were used for principal component analysis, which revealed that the dynamics of the precipitation can be divided into five orthogonal principal components. The first five principal components explain 82.6% of the feature space variation. The timing of the onset of C. gibelio spawning in 95% of cases occurs on the 113–139th days of the year (on average, it takes place on the 125th day). Regression analysis revealed that the climate principal components and types of the lake systems can explain 79% of the variation in the timing of the onset of C. gibelio spawning. The water temperature at the time of C. gibelio spawning was exposed to natural dynamics in year aspect. The local minimum of the onset of spawning temperatures occured in the mid 2000s. Total of 69% of the water temperature variation at which spawning begins can be described by climatic predictors and water biotope types. The variation explained by some temperature principal components may be increased considerably after including as covariates such variables as the precipitation principal component and the biotope type. This principal component which represents the high frequency variation of the air temperature regime with a characteristic period 20 and 45 days has the highest explanation ability of all the components and is a constant explanatory predictor for all considered spawning characteristics
Tensor analyzing power Ayy in deuteron inclusive breakup at large Pt and spin structure of deuteron at short internucleonic distances
The Ayy data for deuteron inclusive breakup off hydrogen and carbon at a
deuteron momentum of 9.0 GeV/c and large Pt of emitted protons are presented.
The large values of Ayy independent of the target mass reflect the sensitivity
of the data to the deuteron spin structure. The data obtained at fixed and
plotted versus Pt clearly demonstrate the dependence of the deuteron spin
structure at short internucleonic distances on two variables. The data are
compared with the calculations using Paris, CD-Bonn and Karmanov's deuteron
wave functions.Comment: 4 pages, 2 figures, talk given at the SPIN2004 Conf., 10-16 Oct.
2004, Triest, Ital
Characteristics of Phenotypic and Genetic Properties of <i>Francisella tularensis</i> 15 NIIEG Vaccine Strain with an Extended Storage Period
Investigated have been cultural-morphological, biochemical and genetic properties of lyophilized cultures of F. tularensis 15 NIIEG vaccine strain, accumulated within 60-years term and deposited at the State Collection of Pathogenic Microorganisms of Scientific Center on Expertise of Medical Application Products. The studies undertaken have demonstrated that storing of the strains in such a form at low temperatures, does not prevent changes of their genetic and phenotypic properties to the full extent. It is established that F. tularensis 15 NIIEG strain lyophilized in 1953, 1966, 1969, 2003 and 2012 maintains its immunogenic properties when cultivated on nutrient media Ft-agar with or without addition of blood, based on dissociation rates (87-99 %) of SR-colonies. While F. tularensis 15 NIIEG strain 1990 contains specified amounts (not less than 80 %) of immunogenic colonies if cultivated on nutrient media with the addition of blood, and fails to meet the requirements - if cultivated without. Identified in F. tularensis 15 NIIEG strain 1987 SR-colony decrement of 70-75 % in case of cultivation with or without addition of blood testifies to the deterioration of its immunogenic properties. RAPD and ERIC typing has showed high stability of the genome of F. tularensis 15 NIIEG cultures lyophilized at different times. Tularemia microbe vaccine strain has unique RAPD and ERIC profiles, insignificant alteration of which is observed upon storage of pathogen subculture in the dried from
Current regulatory requirements for non-clinical evaluation of prophylactic vaccines
Vaccines are subject to specific regulatory requirements for the evaluation of their quality, safety, and efficacy. In 2005, the World Health Organisation (WHO), as the main international organisation coordinating measures to combat infectious disease outbreaks, began developing documents on the evaluation of vaccine quality, safety, and efficacy. The world’s leading regulatory authorities (FDA, EMA, etc.) have also issued recommendations for conducting non-clinical studies of vaccines.The aim of this study was a critical review of the regulatory requirements established by foreign national and international regulatory authorities for non-clinical evaluation of the safety and efficacy of vaccines.According to the study results, since the 2000s, the WHO and the world’s leading regulatory authorities have produced more than 40 regulatory documents describing certain aspects of non-clinical studies of the safety and efficacy of vaccines. These documents can be divided into two groups: the first group addresses non-clinical studies of vaccines in general, and the second one dwells upon the evaluation of the quality, safety, and efficacy of specific types of vaccines. For the Russian guidelines on non-clinical evaluation of the quality, safety, and efficacy of immunobiologicals, the latest revision dates back to 2013 and does not provide any information on new medicinal products. Currently, work is underway to prepare the regulatory framework for medicines, including vaccines, in the Member States of the Eurasian Economic Union (EAEU). This review of regulatory documents on non-clinical safety and efficacy studies of vaccines may be useful in drafting harmonised guidelines for the relevant groups of vaccines in the EAEU. It may also be of use to developers, manufacturers, and researchers involved in the creation and non-clinical study of vaccines
Tensor Ayy and vector Ay analyzing powers in the H(d,d')X and ^{12}C(d,d')X reactons at initial deuteron momenta of 9 GeV/c in the region of baryonic resonances excitation
The angular dependence of the tensor Ayy and vector Ay analyzing powers in
the inelastic scattering of deuterons with a momentum of 9.0 GeV/c on hydrogen
and carbon have been measured. The range of measurements corresponds to the
baryonic resonance excitation with masses 2.2--2.6 GeV/c^2. The Ayy data being
in good agreement with the previous results demonstrate an approximate
scaling up to -1.5 (GeV/c)^2. The large values of A_y show a significant role
of the spin-dependent part of the elementary amplitude of the NN->NN* reaction.
The results of the experiment are compared with model predictions of the
plane-wave impulse approximation.Comment: 7 pages, 7 figures. submitted to Yad.Fi
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