Quality of life of school and university students with acne

Acne may have severe negative impact on different aspects of patient health-related quality of life (HRQoL). Prevalence of acne in university and school students is high, and the HRQoL of students with acne from different countries was studied. There is a lack of studies on direct comparison of HRQoL impairment of university and school students with acne. The Cardiff Acne Disability Index (CADI) was used to assess the HRQOL in university and school students with self-assessed acne. The CADI results from 159 university and 99 school students with self-reported acne were obtained. Mean age of university and school students was 20.99±1.47 (mean ± Standard Deviation) and 14.10±0.51 years, respectively. Reported impact on QoL of university students was significantly higher (3.33±2.26 and 2.76±2.42, P&lt;0.05). Total CADI scores negatively correlated with the age of university students (r=-0.16; P&lt;0.05). Analysis of gender differences of university students showed that negative correlation of HRQoL with age was present in women (r=-0.22; P&lt;0.05) but absent in male students (r=0.05; P=0.77). Female university students reported more severe impact of acne on their life (2.55±2.31 in male and 3.59±2.20 in female students, P&lt;0.01). Our results showed that university students experience higher impact of acne on their life than school students. The highest is the impact on young female university students. We recommend paying more attention to the psychological aspects of young female students with acne during consultations. </p

Quality of life of school and university students with acne

Acne may have severe negative impact on different aspects of patient health-related quality of life (HRQoL). Prevalence of acne in university and school students is high, and the HRQoL of students with acne from different countries was studied. There is a lack of studies on direct comparison of HRQoL impairment of university and school students with acne. The Cardiff Acne Disability Index (CADI) was used to assess the HRQOL in university and school students with self-assessed acne. The CADI results from 159 university and 99 school students with self-reported acne were obtained. Mean age of university and school students was 20.99±1.47 (mean ± Standard Deviation) and 14.10±0.51 years, respectively. Reported impact on QoL of university students was significantly higher (3.33±2.26 and 2.76±2.42, P&lt;0.05). Total CADI scores negatively correlated with the age of university students (r=-0.16; P&lt;0.05). Analysis of gender differences of university students showed that negative correlation of HRQoL with age was present in women (r=-0.22; P&lt;0.05) but absent in male students (r=0.05; P=0.77). Female university students reported more severe impact of acne on their life (2.55±2.31 in male and 3.59±2.20 in female students, P&lt;0.01). Our results showed that university students experience higher impact of acne on their life than school students. The highest is the impact on young female university students. We recommend paying more attention to the psychological aspects of young female students with acne during consultations. </p

Switching between Hydrogenation and Olefin Transposition Catalysis via Silencing NH Cooperativity in Mn(I) Pincer Complexes

While Mn-catalyzed (de)hydrogenation of carbonyl derivatives has been well established, the reactivity of Mn hydrides with olefins remains very rare. Herein, we report a Mn(I) pincer complex that effectively promotes site-controlled transposition of olefins. This reactivity is shown to emerge once the N–H functionality within the Mn/NH bifunctional complex is suppressed by alkylation. While detrimental for carbonyl (de)hydrogenation, such masking of the cooperative N–H functionality allows for the highly efficient conversion of a wide range of allylarenes to higher-value 1-propenybenzenes in near-quantitative yield with excellent stereoselectivities. The reactivity toward a single positional isomerization was also retained for long-chain alkenes, resulting in the highly regioselective formation of 2-alkenes, which are less thermodynamically stable compared to other possible isomerization products. The detailed mechanistic analysis of the reaction between the activated Mn catalyst and olefins points to catalysis operating via a metal–alkyl mechanism─one of the three conventional transposition mechanisms previously unknown in Mn complexes

Spectroscopic assessment of charge mobility in organic semiconductors

Rapid progress in organic electronics demands new highly efficient organic semiconducting materials. Nevertheless, only few materials have been created so far that show reliable band-like transport with high charge mobilities, which reflects the two main obstacles in the field: the poor understanding of charge transport in organic semiconductors (OSs) and the difficulty of its quantification in devices. Here, we present a spectroscopic method for assessment of the charge transport in organic semiconductors. We show that the intensities of the low-frequency Raman spectrum allow calculation of the dynamic disorder that limits the charge carrier mobility. The spectroscopically evaluated mobility clearly correlates with the device charge mobility reported for various OSs. The proposed spectroscopic method can serve as a powerful tool for a focused search of new materials and highlights the disorder bottleneck in the intrinsic charge transport in high-mobility organic semiconductors

Novel hydrogen clathrate hydrate

We report a new hydrogen clathrate hydrate synthesized at 1.2 GPa and 298 K documented by single-crystal X-ray diffraction, Raman spectroscopy, and first-principles calculations. The oxygen sublattice of the new clathrate hydrate matches that of ice II, while hydrogen molecules are in the ring cavities, which results in the trigonal R3c or R-3c space group (proton ordered or disordered, respectively) and the composition of (H2O)6H2. Raman spectroscopy and theoretical calculations reveal a hydrogen disordered nature of the new phase C1', distinct from the well-known ordered C1 clathrate, to which this new structure transforms upon compression and/or cooling. This new clathrate phase can be viewed as a realization of a disordered ice II, unobserved before, in contrast to all other ordered ice structures.Comment: 9 pages, 4 figures, 1 table; Supplementary materials: Materials and Methods, Supplementary Figures S1-S8, Tables S1-S3, and Bibliography with 18 Reference

Revisiting Van Der Waals Radii: From Comprehensive Structural Analysis to Knowledge-Based Classification of Interatomic Contacts

Weak noncovalent interactions are responsible for structure and properties of almost all supramolecular systems, such as nucleic acids, enzymes, and pharmaceutical crystals. However, the analysis of their significance and structural role is not straightforward and commonly requires model studies. Herein we describe an efficient and universal approach for the analysis of noncovalent interactions and determination of vdW radii using the Line-of-Sight (LoS) concept. The LoS allows to unambiguously identify and classify the “direct” interatomic contacts in complex molecular systems. This approach not only provides an improved theoretical base to molecular “sizes” but also enables the quantitative analysis of specificity, anisotropy and steric effects of intermolecular interactions

Prospects for using aluminum matrix composite materials in the automotive industry

The scope of the use of aluminum-alloy-based metal-matrix composite materials has been expanding in recent years. However, the high cost of raw materials is a considerable deterrent to the widespread implementation of products made of such composites. Therefore, the ranges of the said materials commercial application are yet inadequate to their technical and operational capabilities. So, methods of making metal-matrix composite materials directly from a liquid melt are currently of interest. This paper presents the theoretical studies and the results of practical experiments for the production of metal-matrix composite material by the internal oxidation method. There are described the results of mechanical tests and the microstructure of specimens confirming theoretical assumptions in the oxidation of aluminum melt array. A comparative analysis is given for the cost of producing an alloy containing 30% of Al2O3 particles obtained by adding the Al2O3 powder and an alloy obtained by the internal oxidation of the aluminum melt. The studied technology provides for the formation of aluminum oxide directly in the aluminum melt, thus enabling to produce a composite material by a single-stage process and ensuring the process efficiency

Intermolecular contacts for 224 001 molecular crystals from Cambridge Structural Database

The dataset consists of 96 enumerated csv-files with data on all intermolecular contacts shorter than 7 Å for 224 001 CSD entries analyzed in the corresponding work on van der Waals radi

Revisiting van der Waals Radii: From Comprehensive Structural Analysis to Knowledge-Based Classification of Interatomic Contacts

Weak noncovalent interactions are responsible for structure and properties of almost all supramolecular systems, such as nucleic acids, enzymes, and pharmaceutical crystals. However, the analysis of their significance and structural role is not straightforward and commonly requires model studies. Herein, we describe an efficient and universal approach for the analysis of noncovalent interactions and determination of van der Waals radii using the line-of-sight (LoS) concept. The LoS allows to unambiguously identify and classify the “direct” interatomic contacts in complex molecular systems. This approach not only provides an improved theoretical base to molecular “sizes” but also enables the quantitative analysis of specificity, anisotropy, and steric effects of intermolecular interactions.ChemE/AlgemeenChemE/Inorganic Systems Engineerin

Local-structure effects on 31P NMR chemical shift tensors in solid state

The effect of the local structure on the P-31 NMR chemical shift tensor (CST) has been studied experimentally and simulated theoretically using the density functional theory gauge-independent-atomic-orbital approach. It has been shown that the dominating impact comes from a small number of noncovalent interactions between the phosphorus-containing group under question and the atoms of adjacent molecules. These interactions can be unambiguously identified using the Bader analysis of the electronic density. A robust and computationally effective approach designed to attribute a given experimental P-31 CST to a certain local morphology has been elaborated. This approach can be useful in studies of surfaces, complex molecular systems, and amorphous materials. Published under license by AIP Publishing