bluuebunny/crossref_metadata_2025_split huggingface dataset:
Halloysite‐reinforced thermoplastic polyurethane nanocomposites: Physico‐mechanical, rheological, and thermal investigations
Authors: Pourmohammadi‐Mahunaki Mohammadali , Haddadi‐Asl Vahid , Roghani‐Mamaqani Hossein , Koosha Mojtaba , Yazdi Mohammad 
Published: May 2020

AbstractDifferent thermoplastic polyurethane (TPU) nanocomposites with various amounts of halloysite nanotube (HNT) were prepared. The morphological, rheological, thermal, mechanical, and electrical properties of the nanocomposites were also investigated. Fourier‐transform infrared spectroscopy shows that increasing HNT results in increased degree of phase separation. Differential scanning calorimetry thermograms indicate positive effects of HNT on the hard phase crystallinity due to interactions between the surface functional groups of nanotubes and the polyurethane hard phase and also disinclination to form spherulites. According to the dynamic mechanical thermal analysis results, storage modulus of the nanocomposites increased up to 185% with increasing the HNT content in the experimental temperature window, which is in accordance with the tensile strength results. Mechanical analysis indicates that the modulus of nanocomposite increased up to 122% with increasing the HNT content. Rheo‐mechanical spectroscopy results showed that by the addition of low contents of HNT into the TPU matrix, the storage modulus did not show significant variations; however, an upturn in storage modulus was observed by increasing the amount of HNT to 4.2 wt%. In addition, the average volume conductivity of HNT‐reinforced nanocomposites was decreased comparing to the pure TPU even at low amounts of HNT. Therefore, addition of HNT into the TPU matrix resulted in higher mechanical properties in the related nanocomposites.
Observation and implications of the Franz‐Keldysh effect in ultrathin GaAs solar cells
Authors: van Eerden Maarten , van Gastel Jasper , Bauhuis Gerard J. , Mulder Peter , Vlieg Elias , Schermer John J. 
Published: May 2020

AbstractVoltage‐dependencies were observed in the external quantum efficiency (EQE) spectra of ultrathin GaAs solar cells. The subbandgap tail was shown to increase going from forward to reverse bias, while at energies above the bandgap, voltage‐dependent oscillations in the EQE were measured. Using optical simulations, it is irrefutably shown that the voltage‐dependencies are caused by the Franz‐Keldysh effect, that is, an electric field‐dependent absorption coefficient near the bandgap. The dependency on voltage of the subbandgap tail is demonstrated to be strongest in thin‐film cells with a textured rear mirror, since the absorptivity below the bandgap is enhanced by light trapping. The voltage‐dependent subbandgap tail has important implications for the use of the reciprocity relation between photovoltaic quantum efficiency and electroluminescence. It is shown that the radiative limit for the open‐circuit voltage of thin‐film cells integrated with light management schemes can be underestimated by more than 25 mV. Consequently, these cells may be assumed to be closer to the radiative limit than they really are.
Large open‐circuit voltage boosting of pure sulfide chalcopyrite Cu(In,Ga)S2 prepared using Cu‐deficient metal precursors
Authors: Kim Shinho , Nagai Takehiko , Tampo Hitoshi , Ishizuka Shogo , Shibata Hajime 
Published: May 2020

AbstractWe performed a comparative study to find out the reasons why it is necessary to prepare the pure sulfide chalcopyrite, Cu(InGa)S2 (CIGS) under a Cu‐deficient condition to improve solar cell performance. It has been shown that CIGS that was grown under Cu‐deficient condition exhibits large open‐circuit voltage (VOC) boosting compared with that the one grown under Cu‐excess condition. Thus, CIGS were prepared from Cu‐excess and Cu‐deficient metal precursor (MP) and characterized concerning the origins of the different VOC. We observed that CIGS prepared using Cu‐excess MP suffered large recombination at buffer/CIGS interface and in bulk, which resulted in serious limitation of the VOC. On the other hand, CIGS prepared from Cu‐deficient MP exhibited largely improved VOC with reduced recombination. We conducted defect analysis using the photoluminescence (PL) method, and CIGS prepared using Cu‐excess MP exhibited strong deep emissions. However, CIGS prepared from Cu‐deficient MP exhibited PL emission characteristics without deep level transition. This implies that a large number of deep level defects exist in the CIGS prepared using Cu‐excess MP, and this might be the reason for the large recombination limiting VOC of the device. Finally, we also present the reason for deep levels in the CIGS prepared using Cu‐excess MP.
Verbotene Ordnung im Flächenland
Authors: Keim Peter 
Published: May 2020

ZusammenfassungPhasenübergänge wie von flüssig nach fest sind mit Symmetriebrüchen verknüpft. Denn im isotropen, homogenen flüssigen Zustand gibt es keine symmetrische Vorzugsrichtung, im anisotropen Kristall schon. Da der flüssige Zustand mehr räumliche Transformationen zulässt, die invariant sind, ist er symmetrischer. Vor diesem Hintergrund besagt das Mermin‐Wagner‐Hohenberg‐Theorem, dass es in Systemen mit weniger als drei Dimensionen (3D) die kontinuierliche Symmetrie, wie sie in Flüssigkeiten vorliegt, nicht zu einer diskreten Symmetrie, wie sie in 3D‐Kristallen existiert, gebrochen werden kann. Demnach dürfte es keine zweidimensionalen (2D) Kristalle geben. Doch Graphen und Kristalle in kolloidalen Monolagen existieren. Dass sie das dürfen, verdanken solche Systeme langwelligen Fluktuationen der Ordnung, die den globalen Symmetriebruch verhindern, lokal aber Ordnung erlauben. Diese Mermin‐Wagner‐Hohenberg‐Fluktuationen wurden kürzlich experimentell nachgewiesen.
Heiße Jupiter, zweite Erden und die Neptunwüste
Authors: Eigmüller Philipp 
Published: May 2020

ZusammenfassungIm vergangenen Vierteljahrhundert hat die Erforschung extrasolarer Planetensysteme große Fortschritte gemacht. Von der ersten Entdeckung sind wir nun zu über 4000 bekannten Exoplaneten gekommen. Die meisten der gefundenen Systeme sehen anders aus als unser Sonnensystem, allerdings wäre ein Planetensystem wie das Sonnensystem auch noch an der Grenze des Beobachtbaren. Hier müssen wir in unseren Möglichkeiten noch einen Schritt weitergehen, bevor wir das „zweite Sonnensystem“ entdecken. Zukünftige Satellitenmissionen wie PLATO werden uns hier helfen.
Den kosmischen Leichtgewichten auf der Spur
Authors: Drexlin Guido , Valerius Kathrin , Weinheimer Christian 
Published: May 2020

ZusammenfassungAuch 90 Jahre nach ihrer „Erfindung“ und über 60 Jahre nach ihrem experimentellen Nachweis geben uns die Neutrinos zahlreiche Rätsel auf. So konnte bisher ihre Masse nicht bestimmt werden, obgleich bereits lange bekannt ist, dass Neutrinos mit Abstand die leichtesten Elementarteilchen sind. Der Mechanismus, durch den die Neutrinos ihre winzige Masse erhalten, bleibt bisher ebenfalls im Dunkeln. Mit dem KATRIN‐Experiment in Karlsruhe, einer hochkomplexen technischen Anlage, ist es nun in einer ersten Messphase gelungen, den erlaubten Bereich der Neutrinomasse um einen Faktor zwei stärker einzugrenzen als bisher. Durch die in den kommenden Jahren bevorstehende weitere Datennahme hofft die Forschung, der Neutrinomasse endlich auf die Spur zu kommen und damit wichtige Fragen in der Kosmologie und der Teilchenphysik zu beantworten.
Healthcare services and medication use among widowed partners of patients deceased due to cancer ‐ results from the Survey of Health, Ageing and Retirement in Europe (SHARE)
Authors: Costa Ana Rute , Alves Luís , Lunet Nuno 
Published: May 2020

AbstractObjectiveThis study aimed to quantify the effect of a cancer death on healthcare and medication use among widowed individuals (Widowed‐Cancer), by comparing this population with partnered individuals and with widowed individuals whose partners were deceased due to cardiovascular diseases (Widowed‐CVD).MethodsData were retrieved from the Sixth Wave of the Survey of Health, Ageing and Retirement in Europe ‐ SHARE, conducted in 2015, in 18 countries. Widowed‐Cancer were matched by country, sex, age and educational level with currently partnered individuals (1:2; n = 901 and n = 1802, respectively) and with Widowed‐CVD (1:1; n = 606 and n = 606, respectively). Adjusted odds ratios (OR) and 95% confidence intervals (95%CI) were computed using logistic regression.ResultsThe use of drugs for sleep problems (OR = 1.42, 95%CI:1.12‐1.80) and anxiety or depression (OR = 1.56, 95%CI:1.20‐2.03) was more common among Widowed‐Cancer than in partnered individuals; a tendency towards higher odds of being hospitalised in the previous year was also observed in Widowed‐Cancer (OR = 1.20, 95%CI:0.98‐1.47). Among participants whose partners were deceased in 2015, Widowed‐Cancer were more likely than Widowed‐CVD to report ≥10 contacts with medical doctors or nurses in the previous year (OR = 3.32, 95%CI:1.20‐9.24; P for interaction = .042) and a higher use of drugs for sleep problems (OR = 14.43, 95%CI:1.74‐119.84; P for interaction = .027).ConclusionWidowed individuals whose partners were deceased due to cancer had a higher use of healthcare, which highlights the importance of improving the quality of end‐of‐life care, even during widowhood.
Electrochemical Characterization of Redox Probes at Gold Screen‐Printed Electrodes: Efforts towards Signal Stability
Authors: Ribeiro José A. , Silva Elisa , Moreira Patrícia S. , Pereira Carlos M. 
Published: May 2020

AbstractIn this work, three universally used redox probes in amperometric biosensing devices, [Fe(CN)6]3−/[Fe(CN)6]4−, Ru[(NH3)6]3+, and ferrocenedimethanol (FDM), were selected to evaluate the stability of electrochemical signals provide by the reporting systems. Studies were carried out at disposable gold screen‐printed electrode (AuSPE) biosensing platforms, commonly used for screening chemical and biological relevant biomolecules. Firstly, electrochemical combined‐surface plasmon resonance (eSPR) studies were performed to evaluated adsorption reversibility and/or formation of redox probe complexes at the bare gold surface when routinely used electrochemical techniques, namely cyclic voltammetry (CV) and square‐wave voltammetry (SWV), are recorded. Then, the results obtained were compared with those obtained at the AuSPE under the same electrochemical conditions. Based on our findings, best experimental conditions, including the type of electrochemical technique used, are speculated for each reporting system in order to improve the analytical signal stability. Finally, a methodology based on SWV technique was applied to modified electrodes to provide a simple and easy tool to ensure diffusion controlled permeability of probes thorough the films to electrode surface.
Multiple Ways Realizing Charge‐State Transform in AuCu Bimetallic Nanoclusters with Atomic Precision
Authors: Li Qinzhen , Chai Jinsong , Yang Sha , Song Yongbo , Chen Tao , Chen Cheng , Zhang Hui , Yu Haizhu , Zhu Manzhou 
Published: May 2020

AbstractThiolate‐protected nanoclusters with different charge states usually show similar structure frameworks but different electronic configurations, which are proved to dramatically affect their properties such as magnetism, photoluminescence, and catalytic activity. Until now, few nanoclusters with alterable charge states have been reported and only some of them are structurally solved, limiting the in‐depth studies on their interesting properties. Here, a new AuCu alloy nanocluster [Au18Cu32(SPhCl)36]2− (HSPhCl = 4‐chlorophenylthiophenol) is synthesized and structurally solved by X‐ray crystallography. Interestingly, it is found that this nanocluster can be reduced to another nanocluster with a different charge state, that is, [Au18Cu32(SPhCl)36]3−. This change in charge states is clearly proved by X‐ray crystallography, electrospray ionization mass spectrometry, thermogravimetric analysis, and electron paramagnetic resonance. Furthermore, several redox methods are carried out to realize the reversible interconversion between these two nanoclusters, including electrochemical redox, introduction of H2O2/NaBH4, and oxidation with silica under air atmosphere. This work offers new insight into the transform progress of charge states with AuCu alloy nanoclusters which contributes to the understanding of the relationship between electronic structure and properties of nanoclusters and further development of AuCu nanoclusters with excellent performance.
Time‐Resolved Fluorescence Anisotropy of a Molecular Rotor Resolves Microscopic Viscosity Parameters in Complex Environments
Authors: Steinmark I. Emilie , Chung Pei‐Hua , Ziolek Robert M. , Cornell Bethan , Smith Paul , Levitt James A. , Tregidgo Carolyn , Molteni Carla , Yahioglu Gokhan , Lorenz Christian D. , Suhling Klaus 
Published: May 2020

AbstractUnderstanding viscosity in complex environments remains a largely unanswered question despite its importance in determining reaction rates in vivo. Here, time‐resolved fluorescence anisotropy imaging (TR‐FAIM) is combined with fluorescent molecular rotors (FMRs) to simultaneously determine two non‐equivalent viscosity‐related parameters in complex heterogeneous environments. The parameters, FMR rotational correlation time and lifetime, are extracted from fluorescence anisotropy decays, which in heterogeneous environments show dip‐and‐rise behavior due to multiple dye populations. Decays of this kind are found both in artificially constructed adiposomes and in live cell lipid droplet organelles. Molecular dynamics simulations are used to assign each population to nano‐environments within the lipid systems. The less viscous population corresponds to the state showing an average 25° tilt to the lipid membrane normal, and the more viscous population to the state showing an average 55° tilt. This combined experimental and simulation approach enables a comprehensive description of the FMR probe behavior within viscous nano‐environments in complex, biological systems.
Light‐Fuelled Self‐Assembly of Cyclic Peptides into Supramolecular Tubules
Authors: Cissé Nicolas , Kudernac Tibor 
Published: May 2020

AbstractThe work performed by supramolecular polymers, such as microtubules and actin filaments, supports the life of the cell, and essentially involves fuel‐driven self‐assembly pathways. Developing fuel‐driven supramolecular polymerization processes is therefore crucial to the realization of mechanically active molecular systems. Here, we demonstrate supramolecular tubules with non‐equilibrium steady states that are fuelled by light. This dynamic supramolecular system features rapid cycles of self‐assembly and disassembly, at rates that appear fast enough to perform mechanical tasks in fluids effectively.
Cell‐Free Protein Synthesis in Bifunctional Hyaluronan Microgels: A Strategy for In Situ Immobilization and Purification of His‐Tagged Proteins
Authors: Heida Thomas , Köhler Tony , Kaufmann Anika , Männel Max J. , Thiele Julian 
Published: May 2020

AbstractThe front cover artwork is provided by the Thiele group at Leibniz IPF Dresden (Germany). The image shows a microgel hosting cell‐free synthesis of green fluorescent protein. Despite its open, membrane‐free nature, the multifunctional microgel is also able to trap proteins inside its polymer matrix. Read the full text of the Article at 10.1002/syst.201900058.
Correction of flashover voltage of catenary insulators based on analysis of soluble salt compositions in saline‐alkali region
Authors: Wang Sihua , Liu Yang , Wu Youlong , Fu Yuanlin 
Published: May 2020

AbstractCalcium sulfate and other slightly soluble salts in the natural pollution of catenary insulators could result in differences in flashover voltages between artificially and naturally polluted insulators at the same salt deposition density. Based on the insulator pollution characteristics in saline‐alkali areas and the saturated water absorption of polluted insulators, the equivalent salt deposit density and nonsoluble deposit density of insulators are corrected according to the influence of other coexisting soluble salts on the solubility of calcium sulfate. The correction formula of the insulator flashover voltage is proposed, which considers the equivalent salt deposit density, nonsoluble deposit density and pollution components. The results from the correction formula are compared with the experimental data from the artificial pollution test of the ceramic cap and pin insulator. The results show that salt‐alkali areas are more easy to flashover than other areas. The remaining pollutants can change the conductivity of the pollutant layer by inhibiting or promoting the dissolution of calcium sulfate. Moreover, its effect on the flashover voltage cannot be ignored. The error between the calculated value based on the correction formula and the experimental data is below 6%. A pollution flashover warning mechanism based on relevant meteorological data is proposed. The results can be used as an important reference for the operation and maintenance of catenary insulators in saline‐alkali areas. © 2020 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Evolution of the Surgical Residency System in Switzerland: An In‐Depth Analysis Over 15 Years
Authors: Moeckli Beat , Burgermeister Lea C. , Siegrist Michael , Clavien Pierre A. , Käser Samuel A. 
Published: May 2020

AbstractBackgroundThe landscape of surgical training has been subject to many changes over the past 15 years. This study examines resident satisfaction, determinants of satisfaction, demographics, working hours and the teaching rate of common operations in a longitudinal fashion with the aim to identify trends, shortcomings and possible ways to improve the current training system.MethodsThe Swiss Medical Association administers an annual survey to all Swiss residents to evaluate the quality of postgraduate medical training (yearly respondents: 687–825, response rate: 68–72%). Teaching rates for general surgical procedures were obtained from the Swiss association for quality management in surgery.ResultsDuring the study period (2003–2018), the number of surgical residents (408–655 (+61%)) and graduates in general surgery per year (42–63 (+50%)) increased disproportionately to the Swiss population. While the 52 working hour restriction was introduced in 2005 reported average weekly working hours did not decline (59.9–58.4 h (−3%)). Workplace satisfaction (6 being highest) rose from 4.3 to 4.6 (+7%). Working climate and leadership culture were the main determinants for resident satisfaction. The proportion of taught basic surgical procedures fell from 24.6 to 18.9% (−23%).ConclusionsThe number of residents and graduates in general surgery has risen markedly. At the same time, the proportion of taught operations is diminishing. Despite the introduction of working hour restrictions, the self‐reported hours never reached the limit. The low teaching rate combined with the increasing resident number represents a major challenge to the maintenance of the current training quality.
The effects of a 2-year physical activity and dietary intervention on plasma lipid concentrations in children: the PANIC Study
Authors: Eloranta Aino-Maija , Sallinen Taisa , Viitasalo Anna , Lintu Niina , Väistö Juuso , Jalkanen Henna , Tompuri Tuomo T. , Soininen Sonja , Haapala Eero A. , Kiiskinen Sanna , Schnurr Theresia M. , Kilpeläinen Tuomas O. , Mikkonen Santtu , Savonen Kai , Atalay Mustafa , Brage Soren , Laaksonen David E. , Lindi Virpi , Ågren Jyrki , Schwab Ursula , Jääskeläinen Jarmo , Lakka Timo A. 
Published: May 2020

Abstract
Purpose
We studied the effects of a physical activity and dietary intervention on plasma lipids in a general population of children. We also investigated how lifestyle changes contributed to the intervention effects.

Methods
We carried out a 2-year controlled, non-randomized lifestyle intervention study among 504 mainly prepubertal children aged 6–9 years at baseline. We assigned 306 children to the intervention group and 198 children to the control group. We assessed plasma concentrations of total, LDL, HDL, and VLDL cholesterol, triglycerides, HDL triglycerides, and VLDL triglycerides. We evaluated the consumption of foods using 4-day food records and physical activity using a movement and heart rate sensor. We analyzed data using linear mixed-effect models adjusted for age at baseline, sex, and pubertal stage at both time points. Furthermore, specific lifestyle variables were entered in these models.

Results
Plasma LDL cholesterol decreased in the intervention group but did not change in the control group ( − 0.05 vs. 0.00 mmol/L, regression coefficient (β) =  − 0.0385, p = 0.040 for group*time interaction). This effect was mainly explained by the changes in the consumption of high-fat vegetable oil-based spreads (β =  − 0.0203, + 47% change in β) and butter-based spreads (β =  − 0.0294, + 30% change in β), moderate-to-vigorous physical activity (β =  − 0.0268, + 30% change in β), light physical activity (β =  − 0.0274, + 29% change in β) and sedentary time (β =  − 0.0270, + 30% change in β). The intervention had no effect on other plasma lipids.

Conclusion
Lifestyle intervention resulted a small decrease in plasma LDL cholesterol concentration in children. The effect was explained by changes in quality and quantity of dietary fat and physical activity.

Clinical Trial Registry Number
NCT01803776, ClinicalTrials.gov
Comparison of the short-term results of single-dose intra-articular peptide with hyaluronic acid and platelet-rich plasma injections in knee osteoarthritis: a randomized study
Authors: Kesiktas Fatma Nur , Dernek Bahar , Sen Ekin Ilke , Albayrak Havva Nur , Aydin Tugba , Yildiz Merve 
Published: May 2020

Abstract
Introduction/objectives
Intra-articular injections may be useful in terms of pain and functional status, in knee osteoarthritis (OA). Besides hyaluronic acid (HA) and platelet-rich plasma (PRP), peptide molecules recently begin to be used. The aim of this study was to compare the efficacy of intra-articular peptide Prostrolane® (CAREGEN Co. Ltd.) injection with that of the HA and PRP in the persons with OA.

Method
Fifty-four patients with OA were included in this prospective, randomized study. Patients were randomized into three groups as intra-articular HA, peptide, and PRP groups. Paracetamol was permitted three times a day to all groups. All the patients were evaluated by the Western Ontario and McMaster Universities Arthritis Index (WOMAC), Health Assessment Questionnaire (HAQ), and visual analogue scale (VAS) at rest and during movements. Measurements performed at the baseline, after the first week of injection, and at the first and third months of follow-up.

Results
Mean age was 55.8 ± 8.9 years. Forty-four (81.6%) were women. A week after the injections, rest and movement pain severity was measured by VAS decreased significantly in all the study groups (p < 0.05). There were no statistically significant differences between the groups in terms of first week pain relief (p > 0.05). WOMAC pain, stiffness, function, and total scores were improved significantly in all the groups a week after the injections (p < 0.05). Improvement continued at the third month control; however, the improvement in the WOMAC pain score was significantly better in the peptide group at the third month control (p < 0.05). The decrease in the rest and movement pain was continued for 3 months except the HA group’s rest pain. There were no differences among the groups for all measurements, except for the WOMAC pain score at 3 months after treatment, which was significantly lower in the peptide group.

Conclusion
As a result, pain relief and functional improvement were obtained after the intra-articular HA, peptide, and PRP injections in OA, and decrease in pain was better in the peptide group.

Key Points• The short-term effects of intra-articular HA, peptide, and PRP injections were compared in knee osteoarthritis.• HA, peptide, and PRP injections may be useful in pain relief and functional improvement in knee osteoarthritis.