Mixing-induced anisotropic correlations in molecular crystalline systems

We investigate the structure of mixed thin films composed of pentacene (PEN) and diindenoperylene (DIP) using X-ray reflectivity and grazing incidence X-ray diffraction. For equimolar mixtures we observe vanishing in-plane order coexisting with an excellent out-of-plane order, a yet unreported disordering behavior in binary mixtures of organic semiconductors, which are crystalline in their pure form. One approach to rationalize our findings is to introduce an anisotropic interaction parameter in the framework of a mean field model. By comparing the structural properties with those of other mixed systems, we discuss the effects of sterical compatibility and chemical composition on the mixing behavior, which adds to the general understanding of interactions in molecular mixtures.Comment: 5 pages, 5 figures, accepted by Phys. Rev. Let

Beyond Born-Mayer: Improved Models for Short-Range Repulsion in ab Initio Force Fields

Short-range repulsion within intermolecular force fields is conventionally described by either Lennard-Jones (<i>A</i>/<i>r</i>¹²) or Born–Mayer (<i>A</i> exp­(−<i>Br</i>)) forms. Despite their widespread use, these simple functional forms are often unable to describe the interaction energy accurately over a broad range of intermolecular distances, thus creating challenges in the development of ab initio force fields and potentially leading to decreased accuracy and transferability. Herein, we derive a novel short-range functional form based on a simple Slater-like model of overlapping atomic densities and an iterated stockholder atom (ISA) partitioning of the molecular electron density. We demonstrate that this Slater–ISA methodology yields a more accurate, transferable, and robust description of the short-range interactions at minimal additional computational cost compared to standard Lennard-Jones or Born–Mayer approaches. Finally, we show how this methodology can be adapted to yield the standard Born–Mayer functional form while still retaining many of the advantages of the Slater-ISA approach

ЛЕЧЕНИЕ И ПРОФИЛАКТИКА АДЕНОИДИТОВ БАКТЕРИАЛЬНЫМИ ЛИЗАТАМИ У ЧАСТО БОЛЕЮЩИХ ДЕТЕЙ

We carried out the analysis of researches devoted to the treatment of children with chronic adenoiditis and hypertrophy of adenoid vegetations. We proved that the usage of topic immunomodulator IRS19 incombination with etiotropic treatment allows to sanate lymphoid tissues in nasopharynx effectively and to preserve its continuity as an important organ supplying unspecific and specific protection of the child’s organism.Проведен анализ исследований, посвященных лечению детей с хроническим аденоидитом и гипертрофией аденоидных вегетаций. Показано, что применение топического иммуномодулятора ИРС 19 в комплексе с этиотропным лечением позволяет более эффективно провести санацию лимфоидной ткани носоглотки и сохранить ее целостность как важного органа, обеспечивающего неспецифическую и специфическую защиту детского организма

Exercise engagement drives changes in cognition and cardiorespiratory fitness after 8 weeks of aerobic training in sedentary aging adults at risk of cognitive decline

BackgroundWith our aging population, many individuals are at risk of developing age-related cognitive decline. Physical exercise has been demonstrated to enhance cognitive performance in aging adults. This study examined the effects of 8 weeks of aerobic exercise on cognitive performance and cardiorespiratory fitness in sedentary aging adults at risk for cognitive decline.MethodsFifty-two participants (age 62.9 ± 6.8, 76.9% female) engaged in eight weeks of moderate-to high-intensity exercise (19 in-person, 33 remotely). Global cognition was measured by the Repeatable Battery for the Assessment of Neuropsychological Status, the Delis-Kaplan Executive Function System, and the Digit Span subtest of the Wechsler Adult Intelligence Scale (WAIS) Fourth Edition. Cardiorespiratory fitness was measured via heart rate recovery at minute 1 (HRR1) and 2 (HRR2), and exercise engagement (defined as percent of total exercise time spent in the prescribed heart rate zone). We measured pre and post changes using paired t-tests and mixed effects models, and investigated the association between cardiorespiratory and cognitive performance using multiple regression models. Cohen's d were calculated to estimate effect sizes.ResultsOverall, 63.4 % of participants demonstrated high engagement (≥ 70% total exercise time spent in the prescribed heart rate zone). There were significant pre-post improvements in verbal fluency and verbal memory, and a significant decrement in working memory, but these were associated with small effect sizes (Cohen's d &lt;0.5). Concerning cardiorespiratory fitness, there was a pre-to-post significant improvement in HRR1 (p = 0.01, d = 0.30) and HRR2 (p &lt; 0.001, d = 0.50). Multiple regressions revealed significant associations between cardiorespiratory and cognitive performance, but all were associated with small effect sizes (Cohen's d &lt; 0.5). Interestingly, there were significant between-group differences in exercise engagement (all p &lt; 0.001), with remote participants demonstrating greater exercise engagement than in-person participants.ConclusionImprovements in cognition and cardiorespiratory fitness were observed after 8 weeks of moderate to high-intensity exercise in aging adults. These results suggest that committing to a regular exercise regimen, even for a brief two-month period, can promote improvements in both cardiorespiratory fitness and cognitive performance, and that improvements are driven by exercise engagement

Order and Disorder in the World of Atoms

164 tr.; 20 cm

Introduction to physics/ Kitaigorodsky

719 hal.: ill.; ind.; 22 cm