Lifetime measurement of excited low-spin states via the (p,p′γ(p,p^{\prime}\gamma) reaction

In this article a method for lifetime measurements in the sub-picosecond regime via the Doppler-shift attenuation method (DSAM) following the inelastic proton scattering reaction is presented. In a pioneering experiment we extracted the lifetimes of 30 excited low-spin states of $^{96}$Ru, taking advantage of the coincident detection of scattered protons and de-exciting $\gamma$-rays as well as the large number of particle and $\gamma$-ray detectors provided by the SONIC@HORUS setup at the University of Cologne. The large amount of new experimental data shows that this technique is suited for the measurement of lifetimes of excited low-spin states, especially for isotopes with a low isotopic abundance, where $(n,n^{\prime}\gamma$) or - in case of investigating dipole excitations - ($\gamma,\gamma^{\prime}$) experiments are not feasible due to the lack of sufficient isotopically enriched target material

Unusual Presentation Of Self-Limiting Chorioretinopathy Possibly Associated With COVID-19

The paper reports on an unusual presentation of self-limiting chorioretinopathy possibly associated with COVID-19 in a 47-year-old woman previously tested positive for SARS-COV-2 by PCR, who presented with decreased VA in her right eye on day 15 after testing. The only symptom she had was anosmia and аgeusia. No therapy was taken during the 14-days quarantine period. The anterior segment was unremarkable on slit lamp examination in both eyes. Fundus examination of the left eye showed no significant findings. On the other hand, the examination of the right eye revealed yellowish creamy deep chorioretinal lesion in central retina. Two weeks later the patient came back for follow-up and it was found that the lesion was decreased in size, with VA improvement. Ocular signs in COVID-19 cases are rarely reported, and most of the ophthalmological changes have been associated usually with viral conjunctivitis. Researchers report also finding such as cotton wool spots, microhemorrhages and some OCT-changes. This case illustrates the possible association between COVID-19 and retinopathy despite the almost asymptomatic presentation

DFT-based Conformational Analysis of a Phospholipid Molecule (DMPC)

The conformational space of the dimyristoyl phosphatidylcholine (DMPC) molecule has been studied using Density Functional Theory (DFT), augmented with a damped empirical dispersion energy term (DFT-D). Fourteen ground-state isomers have been found with total energies within less than 1 kcal/mol. Despite differences in combinations of their torsion angles, all these conformers share a common geometric profile, which includes a balance of attractive, repulsive and constraint forces between and within specific groups of atoms. The definition of this profile fits with most of the structural characteristics deduced from measured NMR properties of DMPC solutions. The calculated vibrational spectrum of the molecule is in good agreement with experimental data obtained for DMPC bilayers. These results support the idea that DMPC molecules preserve their individual molecular structures in the various assemblies.Comment: 31 pages, 6 Tables, 4 Figure

Self-esteem in adolescents

PURPOSE. Self-esteem is an overall evaluation of the person’s value, expressed in a positive or negative orientation towards himself. Its development starts from birth and is constantly changing under the influence of experience (1). Especially important is the role of self-esteem in the process of adolescence. During this period, it correlates with both academic achievement and mental health. The aim of this study is to analyze the correlation between academic achievement and self-esteem among teenagers. Forty 14-year-old students (20 boys and 20 girls) with excellent, very good and good results in school were examined. Methods: Self-Esteem Scale (RSE) (2). The study results show that girls have significantly more negative attitudes towards themselves (x = 32.25) comparing with boys (x = 25.14). These results support the need for further research to explore how individual and contextual factors affect the development of self-esteem over the school years

Trait and state anxiety as factors of threshold and tolerance to experimentally induced pain

Pain is an experience that has physical, psychological and social aspects. Sensitivity to pain is individual and depends on psychological factors. Studies have shown that anxiety is associated with the perception of experimentally induced pain. PURPOSE: The purpose of the present study is to examine the relationship between anxiety, threshold and tolerance to experimentally induced pain in healthy persons. METHODS: 35 healthy persons at the age from 19 to 39, 20 women and 15 men were examined. Methods: Spielberger’s questionnaire, Cold pressor test, Visual Analog Scale for Pain, Descriptive statistics, Correlation analysis, Mann-Whitney’s Test. RESULTS: Significant differences in tolerance to pain were identified depending on the levels of state anxiety (U=12.5, Р=0.037). The state anxiety was greatly related to the intensity of the pain experienced. (Spearman rho=0.49, P=0.008). Significant differences were not found in threshold, tolerance and intensity of pain depending on the levels of trait anxiety in the examined people. CONCLUSIONS: The increased levels of state anxiety in healthy persons exposed to experimentally induced pain suggest a weaker endurance to pain and perceiving it as stronger

Kaposi's sarcoma-associated herpesvirus oncoprotein K13 protects against B cell receptor induced growth arrest and apoptosis through NF-κB activation

Kaposi's sarcoma-associated herpesvirus (KSHV) has been linked to the development of Kaposi's sarcoma, primary effusion lymphoma and multicentric Castleman's disease (MCD). We have characterized the role of KSHV-encoded viral FLICE inhibitory protein K13 in the modulation of anti-IgM induced growth arrest and apoptosis in B cells. We demonstrate that K13 protects WEHI 231, an immature B cell line, against anti-IgM induced growth arrest and apoptosis. The protective effect of K13 was associated with the activation of the NF-κB pathway and was deficient in its mutant, K13-58AAA, and a structural homolog, vFLIP E8, which lack NF-κB activity. K13 upregulated the expression of NF-κB subunit RelB and blocked the anti-IgM induced decline in c-Myc and rise in p27(Kip1) that have been associated with growth arrest and apoptosis. K13 also upregulated the expression of Mcl-1, an anti-apoptotic member of the Bcl2 family. Finally, K13 protected the mature B cell line Ramos against anti-IgM induced apoptosis through NF-κB activation. Inhibition of anti-IgM induced apoptosis by K13 may contribute to the development of KSHV-associated lymphoproliferative disorders

Identification of durable and non-durable FeN x sites in Fe–N–C materials for proton exchange membrane fuel cells

While Fe–N–C materials are a promising alternative to platinum for catalysing the oxygen reduction reaction in acidic polymer fuel cells, limited understanding of their operando degradation restricts rational approaches towards improved durability. Here we show that Fe–N–C catalysts initially comprising two distinct FeNx sites (S1 and S2) degrade via the transformation of S1 into iron oxides while the structure and number of S2 were unmodified. Structure–activity correlations drawn from end-of-test 57Fe Mössbauer spectroscopy reveal that both sites initially contribute to the oxygen reduction reaction activity but only S2 substantially contributes after 50 h of operation. From in situ 57Fe Mössbauer spectroscopy in inert gas coupled to calculations of the Mössbauer signature of FeNx moieties in different electronic states, we identify S1 to be a high-spin FeN4C12 moiety and S2 a low- or intermediate-spin FeN4C10 moiety. These insights lay the groundwork for rational approaches towards Fe–N–C cathodes with improved durability in acidic fuel cells. [Figure not available: see fulltext.

Mixed-symmetry octupole and hexadecapole excitations in N=52 isotones

In addition to the well-established quadrupole mixed-symmetry states, octupole and hexadecapole excitations with mixed-symmetry character have been recently proposed for the N = 52 isotones 92Zr and 94Mo. We performed two inelastic proton-scattering experiments to study this kind of excitations in the heaviest stable N = 52 isotone 96Ru. From the combined experimental data of both experiments absolute transition strengths were extracted

Combinatorial–computational–chemoinformatics (C3) approach to finding and analyzing low-energy tautomers

Finding the most stable tautomer or a set of low-energy tautomers of molecules is critical in many aspects of molecular modelling or virtual screening experiments. Enumeration of low-energy tautomers of neutral molecules in the gas-phase or typical solvents can be performed by applying available organic chemistry knowledge. This kind of enumeration is implemented in a number of software packages and it is relatively reliable. However, in esoteric cases such as charged molecules in uncommon, non-aqueous solvents there is simply not enough available knowledge to make reliable predictions of low energy tautomers. Over the last few years we have been developing an approach to address the latter problem and we successfully applied it to discover the most stable anionic tautomers of nucleic acid bases that might be involved in the process of DNA damage by low-energy electrons and in charge transfer through DNA. The approach involves three steps: (1) combinatorial generation of a library of tautomers, (2) energy-based screening of the library using electronic structure methods, and (3) analysis of the information generated in step (2). In steps 1–3 we employ combinatorial, computational and chemoinformatics techniques, respectively. Therefore, this hybrid approach is named “Combinatorial*Computational*Chemoinformatics”, or just abbreviated as C3 (or C-cube) approach. This article summarizes our developments and most interesting methodological aspects of the C3 approach. It can serve as an example how to identify the most stable tautomers of molecular systems for which common chemical knowledge had not been sufficient to make definite predictions