bluuebunny/crossref_metadata_2025 huggingface dataset:
Praktische Empfehlungen der Deutschen Diabetes Gesellschaft zum Diabetesmanagement bei Patientinnen und Patienten mit einer COVID-19-Erkrankung
Authors: Bornstein Stefan R. , Gallwitz Baptist , Kellerer Monika , Ludwig Barbara , Müller-Wieland Dirk , Neu Andreas , Reuter Hans-Martin , Roden Michael , Seufert Jochen
Published: June 2020

Bei Menschen mit einer Infektion mit dem neuartigen Coronavirus SARS-CoV-2 und einer COVID-19-Erkrankung sind Diabetes mellitus und kardiovaskuläre Erkrankungen sehr häufige Komorbiditäten. Patienten mit Diabetes und Begleit- beziehungsweise Folgeerkrankungen scheinen ein erhöhtes Risiko für einen schweren Krankheitsverlauf bei COVID-19 einschließlich ARDS und Multiorganversagen zu haben. Die genauen Zusammenhänge zwischen Diabetes und COVID-19-Krankheitsverlauf sind noch nicht vollständig geklärt. Die DDG hat daher prinzipielle Handlungsempfehlungen zur Diabetestherapie bei Diabetes mellitus und COVID-19-Erkrankung zusammengefasst.
Effects and Safety of Sitagliptin in Non-Alcoholic Fatty Liver
Disease: A Systematic Review and Meta-Analysis
Authors: Zhang Yuhan , Cai Tian , Zhao Junyu , Guo Congcong , Yao Jinming , Gao Peng , Dong Jianjun , Liao Lin
Published: June 2020

Non-alcoholic fatty liver disease (NAFLD) is currently the most common cause of
chronic liver disease. However, the treatment is limited. The aim of this
meta-analysis was to evaluate the effects and safety of sitagliptin, a selective
inhibitor of dipeptidyl peptidase-4 (DPP-4I), in treating NAFLD. Studies were
sourced from electronic databases including PubMed, CENTRAL (Cochrane Controlled
Trials Register), Embase, Medline, Web of Science, Clinical Trials, and CNKI to
identify all randomized controlled clinical trials (RCTs) and non-RCTs in adult
patients with NAFLD. Key outcomes were changes in serum levels of liver enzymes
and improvement in hepatic histology and fat content measured by imaging or
liver biopsy. Stata14.0 and RevMan5.3 were used for the meta-analysis. Seven
studies with 269 NAFLD patients were included. Compared to the control group,
sitagliptin treatment improved serum gamma-glutamyl transpeptidase (GGT) levels
in the RCT subgroup (SMD = 0.79, 95% CI: 0.01–1.58).
However, there was no significant improvement in serum alanine aminotransferase
(ALT) or aspartate aminotransferase (AST) levels following sitagliptin
treatment. Four of the included studies performed liver imaging, but sitagliptin
treatment did not result in a significant reduction in liver fat content. Only
five participants developed sitagliptin-related gastrointestinal discomfort. Our
study suggests that sitagliptin effects individuals with NAFLD by improving
serum GGT. Although sitagliptin is safe and well tolerated in NAFLD patients, it
exerts no beneficial effects on liver transaminase and liver fat content in
these patients.
ADHD: Current Concepts and Treatments in Children and Adolescents
Authors: Drechsler Renate , Brem Silvia , Brandeis Daniel , Grünblatt Edna , Berger Gregor , Walitza Susanne
Published: June 2020

Attention deficit hyperactivity disorder (ADHD) is among the most frequent disorders within child and adolescent psychiatry, with a prevalence of over 5%. Nosological systems, such as the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) and the International Classification of Diseases, editions 10 and 11 (ICD-10/11) continue to define ADHD according to behavioral criteria, based on observation and on informant reports. Despite an overwhelming body of research on ADHD over the last 10 to 20 years, valid neurobiological markers or other objective criteria that may lead to unequivocal diagnostic classification are still lacking. On the contrary, the concept of ADHD seems to have become broader and more heterogeneous. Thus, the diagnosis and treatment of ADHD are still challenging for clinicians, necessitating increased reliance on their expertise and experience. The first part of this review presents an overview of the current definitions of the disorder (DSM-5, ICD-10/11). Furthermore, it discusses more controversial aspects of the construct of ADHD, including the dimensional versus categorical approach, alternative ADHD constructs, and aspects pertaining to epidemiology and prevalence. The second part focuses on comorbidities, on the difficulty of distinguishing between “primary” and “secondary” ADHD for purposes of differential diagnosis, and on clinical diagnostic procedures. In the third and most prominent part, an overview of current neurobiological concepts of ADHD is given, including neuropsychological and neurophysiological researches and summaries of current neuroimaging and genetic studies. Finally, treatment options are reviewed, including a discussion of multimodal, pharmacological, and nonpharmacological interventions and their evidence base.
Efficacy of Cyanoacrylate Glue Ablation of Primary Truncal Varicose Veins Compared to Existing Endovenous Techniques: A Systematic Review of the Literature
Authors: Dimech Anthony Pio , Cassar Kevin
Published: June 2020

Introduction One-third of adults in the United States and United Kingdom suffer from varicose veins. n-butyl-2-cyanoacrylate (NBCA) glue is a novel endovascular, nontumescent, nonthermal ablation technique for treatment of this condition. It has proved effective in multiple studies since its first use in 2013. The aim of this systematic review is to assess the efficacy of NBCA in ablating primary truncal varicose veins and eliminating reflux compared with existing endovascular techniques. Secondary outcomes include complications and quality of life.

Methods PRISMA was used as a guide and studies were screened for risk of bias and methodological quality. Subjects had to be ≥18 years of age and followed-up posttreatment with color Duplex ultrasound (DUS). Eligibility criteria included saphenofemoral junction (SFJ) or saphenopopliteal junction (SPJ) incompetence with reflux down truncal veins lasting >0.5 seconds on DUS interrogation and a Clinical, Etiological, Anatomical, and Pathophysiological classification of venous disorders ranging between C1 and C6.

Results Out of 2,910 patients (3,220 veins) in 17 studies, 1,981 were administered NBCA, 445 radiofrequency ablation (RFA), and 484 endovenous laser ablation (EVLA) with mean procedure times of 25.7, 23.2, and 28.7 minutes, respectively. Mean recruitment period was 9 months (1–36 months) and followed-up for an average of 12.3 months (1–36 months). The majority were C2 to C3. Two-year occlusion rates were 93.7, 90.9, and 91.5% for NBCA, RFA, and EVLA, respectively. NBCA-treated patients experienced the least complications, with bruising, phlebitis, and pain being the most prevalent. Quality of life improved equally in all three modalities.

Conclusion NBCA is simple to administer, safe, and effective even without compression stockings. Further studies are required to assess longer-term benefit and the effect of anticoagulation on vein obliteration.
Diagnostic Value of the Neutrophil/Lymphocyte Ratio, Platelet/Lymphocyte Ratio, and Thrombocytosis in the Preoperative Investigation of Ovarian Masses
Authors: Yoshida Adriana , Sarian Luís Otavio , Marangoni Marcos , Firmano Isis Caroline , Derchain Sophie Françoise
Published: June 2020

Objective To evaluate the diagnostic accuracy of cancer antigen 125 (CA125) and complete blood count (CBC) parameters, such as the neutrophil to lymphocyte ratio (NLR), the platelet to lymphocyte ratio (PLR), and thrombocytosis in patients with ovarian masses.

Methods The present is a retrospective study conducted at a single tertiary hospital from January 2010 to November 2016. We included consecutive women referred due to suspicious adnexal masses. The CBC and CA125 were measured in the serum of 528 women with ovarian masses before surgery or biopsy. We evaluated the diagnostic performance of the NLR, PLR, platelets (PLTs), CA125, and the associations between them. We tested the clinical utility of the CBC parameters and CA125 in the discrimination of ovarian masses through decision curve analysis (DCA).

Results The best balance between sensitivity and specificity was obtained by the associations of CA125 or PLTs ≥ 350/nL, with 70.14% and 71.66%, CA125 or PLTs ≥ 400/nL, with 67.30% and 81.79%, CA125 or PLR, with 76.3% and 64.87%, and CA125 or NLR, with 71.09% and 73.89% respectively. In the DCA, no isolated CBC parameter presented a higher clinical utility than CA125 alone.

Conclusion We showed that no CBC parameter was superior to CA125 in the prediction of the malignancy of ovarian tumors in the preoperative scenario.
Evaluation of a Laparoscopic Multi-approach Training for Obstetrics and Gynecology Residents
Authors: Maranhao Débora Davalos Albuquerque , Barison Gustavo Anderman Silva , Alvarenga-Bezerra Vanessa , Ferreira Laís Assenheimer de Paula , Schindler Leal Anucha Andrade , Moretti-Marques Renato , Podgaec Sergio , Zlotnik Eduardo , Gomes Mariano Tamura Vieira
Published: June 2020

Objective To analyze the applicability and efficiency of a multi-approach laparoscopic training in improving basic laparoscopic skills of obstetrics and gynecology (OBGYN) residents.

Methods Cross-sectional, observational and descriptive study, developed at the Experimentation and Surgery Training Center (CETEC, in the Portuguese acronym) of the Hospital Israelita Albert Einstein with OBGYN residents. Theoretical and practical tests were applied to 24 OBGYN residents to assess their laparoscopic skills before and after their participation in an 8-week course. The course involved theoretical lectures and practical laparoscopic surgery exercises developed using rubber models, black boxes, virtual simulators and animal models (pigs).

Results There was an overall improvement in the ability of the residents, with an increase in the number of correct answers in the theoretical evaluation and decrease in the time needed to perform practical tests (needle holder assembly and laparoscopic node). The course was evaluated by the students as highly relevant for both improving their surgical skills and motivating them to continue practicing.

Conclusion Laparoscopic training using multiple approaches resulted in significant improvement of surgical skills with a high satisfaction level of the participants. Further studies are still needed to measure the long-term retention of these acquired skills.
De Novo Inverted Duplication Deletion of 4p in a 14-Week-Old Male Fetus Aborted Due to Multiple Anomalies
Authors: Fontana Paolo , Bernardini Laura , Lombardi Cinzia , Giuffrida Maria Grazia , Ciavarella Maria , Capalbo Anna , Maioli Marianna , Scarano Francesca , Cantalupo Giuseppina , Falco Mariateresa , Scarano Gioacchino , Lonardo Fortunato
Published: June 2020

Inverted duplications deletions are rare, complex, and nonrecurrent chromosomal rearrangements associated with a variable phenotype. In this case report, we described the phenotype and genotype of a 14-week-old male fetus, who was aborted after discovery of multiple anomalies (septal cystic hygroma, open abdominal wall, and a nonidentifiable lower limb). At autopsy, fluorescence in situ hybridization and array comparative genomic hybridization identified an inverted duplication with terminal deletion of 4p [46,XY,der(4)del(p16.3)dup(4)(p15.2p16.3)]. Only five genotypically similar cases have been reported, and we hope our case contribution will add meaningful to the body of knowledge.
Magnetic levitation and compression of compact tori
Authors: Dunlea Carl , Howard Stephen , Zawalski Wade , Epp Kelly , Mossman Alex , Xiao Chijin , Hirose Akira
Published: June 2020

The magnetic compression experiment at General Fusion was a repetitive non-destructive test to study plasma physics to magnetic target fusion compression. A compact torus (CT) is formed with a co-axial gun into a containment region with an hour-glass shaped inner flux conserver and an insulating outer wall. External coil currents maintain the CT off the outer wall (radial levitation) and then rapidly compress it inward. The optimal external coil configuration greatly improved both the levitated CT lifetime and the rate of shots with good flux conservation during compression. As confirmed by spectrometer data, the improved levitation field profile reduced plasma impurity levels by suppressing the interaction between plasma and the insulating outer wall during the formation process. Significant increases in the magnetic field, density, and ion temperature were routinely observed at magnetic compression despite the prevalence of an instability, thought be an external kink, at compression. Matching the decay rate of the levitation coil currents to that of the internal CT currents resulted in a reduced level of MHD activity associated with unintentional compression by the levitation field and a higher probability of long-lived CTs. An axisymmetric finite element MHD code that conserves system energy, particle count, angular momentum, and toroidal flux was developed to study CT formation into a levitation field and magnetic compression. An overview of the principal experimental observations and comparisons between simulated and experimental diagnostics are presented.
High-efficiency electrically direction-controllable spoof surface plasmon polaritons coupler
Authors: Yang Xiaoqing , Luo Jiefang , Gu Dezhen , Su Piqiang , Zhang Man , Zhu Zhanxia , Yuan Jianping
Published: June 2020

We propose a design of high-efficiency and direction-controllable spoof surface plasmon polaritons (SSPPs) coupler based on a Pancharatnam–Berry (PB) metasurface and a diode-controlled, linear-to-circular polarization conversion metasurface (PCM). The PB metasurface was designed to achieve high-efficiency excitation of SSPPs by manipulating the phase distribution. The PCM was placed above the PB metasurface at a certain distance, and the propagation direction of SSPPs could be controlled by changing the bias voltage of PCM. To validate the feasibility of the proposed design, a SSPPs coupler was fabricated and assessed. The experimental results were in good agreement with the simulation results. The conversion efficiency from the free space wave to SSPPs was obtained to be as high as 0.76 at 10 GHz, and the propagation direction of SSPPs became controllable under the normal incidence of x-polarized waves on the PCM. Compared to conventional devices such as prism, grating, and gradient-index metasurfaces, the proposed SSPPs coupler is more suitable for SSPPs excitation, thereby providing an interesting route toward developing plasmonic devices.
Determination of silicon wafer site flatness using dual heterodyne interferometers with sub-nanometer precision
Authors: Tahara Kazuhiko , Matsuoka Hideki , Morioka Noritaka , Tsunaki Hidetoshi , Kannaka Masato , Kita Takashi
Published: June 2020

Precise measurement of wafer flatness with high sensitivity and high spatial resolution is essential to realize high yields in nano-scale lithography because the depth of focus in this technology is relatively small. We report on a highly precise site flatness measurement system that employs a pair of heterodyne interferometers and achieves sub-nanometer precision for polished 300-mm silicon wafers. The determined overall mean standard deviation for the site flatness front-surface least-squares fit range is 0.21 nm. Furthermore, this system allows us to obtain images of the wafer flatness via scanning with a high spatial resolution of approximately 12 µm. These results suggest that the heterodyne interferometer-based system is a suited candidate for use at the next-generation 16-nm half-pitch technology node.
Structured channel metamaterials for deep sub-wavelength resolution in guided ultrasonics
Authors: Birir John K. , Gatari Michael J. , Rajagopal Prabhu
Published: June 2020

Experimental results on deep subwavelength resolution of defects are presented for the first time in the context of guided ultrasonic wave inspection of defects, using novel “structured channel” metamaterials. An Aluminum bar with side-drilled holes is used as a test sample, interrogated by the fundamental bar-guided symmetric mode. Simulations were conducted to optimize dimensional parameters of the metamaterial structure. Experiments using metamaterials fabricated accordingly demonstrate a resolution down to 1/72 of the operating wavelength, potentially bringing the resolution of guided wave inspection to the same range as that of bulk ultrasonics. This work has much promise for remote inspection in industry and biomedicine.
Examination of synthetic gas puff imaging diagnostic data from a gyrokinetic turbulence code
Authors: Stotler D. P. , Ku S. , Zweben S. J. , Chang C. S. , Churchill R. M. , Terry J. L.
Published: June 2020

A synthetic gas puff imaging (GPI) diagnostic has been developed for the purpose of validating the three-dimensional gyrokinetic turbulence code XGC. The synthetic diagnostic is described and applied to XGC simulations of two Alcator C-Mod discharges. The turbulence characteristics deduced from the resulting simulated GPI frames, using analysis techniques similar to those applied to experimental data, are compared with locally derived characteristics extracted directly from the XGC output. The comparison of the two is shown to be potentially impacted by misalignment between the GPI view and the magnetic field, the dependence of the light emission on the electron density and temperature, and spatial and temporal variations in the neutral gas cloud induced by the turbulent plasma fluctuations. We conclude that quantitative and, in some cases even qualitative, validation of turbulence simulations need to account for these effects. While we cannot directly compare our results with experimental data due to the absence of high quality GPI data from the shots and times simulated by XGC, we do relate the overall characteristics obtained from the synthetic GPI analysis to published Alcator C-Mod GPI data.
Polarizing crowds: Consensus and bipolarization in a persuasive arguments model
Authors: Barrera Lemarchand Federico , Semeshenko Viktoriya , Navajas Joaquín , Balenzuela Pablo
Published: June 2020

Understanding the opinion formation dynamics in social systems is of vast relevance in diverse aspects of society. In particular, it is relevant for political deliberation and other group decision-making processes. Although previous research has reported different approaches to model social dynamics, most of them focused on interaction mechanisms where individuals modify their opinions in line with the opinions of others, without invoking a latent mechanism of argumentation. In this paper, we present a model where changes of opinion are due to explicit exchanges of arguments, and we analyze the emerging collective states in terms of simple dynamic rules. We find that, when interactions are equiprobable and symmetrical, the model only shows consensus solutions. However, when either homophily, confirmation bias, or both are included, we observe the emergence and dominance of bipolarization, which appears due to the fact that individuals are not able to accept the contrary information from their opponents during exchanges of arguments. In all cases, the predominance of each stable state depends on the relation between the number of agents and the number of available arguments in the discussion. Overall, this paper describes the dynamics and shows the conditions wherein deliberative agents are expected to construct polarized societies.
Spin-resolved near-field scanning optical microscopy for mapping of the spin angular momentum distribution of focused beams
Authors: Yin Xiaojin , Shi Peng , Du Luping , Yuan Xiaocong
Published: June 2020

We proposed and built a near-field scanning optical microscope (NSOM) to enable the characterization of the spin angular momentum (SAM) distribution of electromagnetic fields with nanoscale resolution. The NSOM probe was composed of a circular nanohole formed in a thick gold film that was deposited on a tapered cone fiber. The near-field signal, when coupled through the nanohole to the fiber, was split and analyzed using a combination of a quarter-wave plate and a polarizer to extract the two circular polarization components of the signal. This allowed us to characterize the out-of-plane SAM component, which was determined using the relationship Sz ∝ IRCP − ILCP. Using the developed system, we mapped the SAM distributions of a variety of tightly focused cylindrical vector vortex beams and thus validated the system's effectiveness. The proposed spin-resolved NSOM could be a valuable tool for studies of both near-field spin optics and topological photonics.
Atomic hydrogen passivation for photoresponsivity enhancement of boron-doped p-BaSi2 films and performance improvement of boron-doped p-BaSi2/n-Si heterojunction solar cells
Authors: Xu Zhihao , Sato Takuma , Benincasa Louise , Yamashita Yudai , Deng Tianguo , Gotoh Kazuhiro , Toko Kaoru , Usami Noritaka , Filonov Andrew B. , Migas Dmitri B. , Shohonov Denis A. , Suemasu Takashi
Published: June 2020

Semiconducting barium disilicide (BaSi2) is an emerging material for solar cell applications, and therefore, defect passivation is critical for improving its solar cell performance. Herein, the effect of atomic hydrogen (H) on the photoresponsivity of 500 nm-thick boron (B)-doped p-BaSi2 films was examined. The photoresponsivity reached ∼4 A/W (about twice the highest reported value for H-passivated undoped BaSi2 films) in B-doped p-BaSi2 films exposed to an atomic H supply for 5 − 10 min because of an increased minority-carrier lifetime, as measured by the microwave-detected photoconductivity decay. Furthermore, a ≥15 min atomic H supply was found to degrade photoresponsivity. Ab initio studies were used to interpret and understand experimental observations by analyzing states in the gap region, which can act as traps, in B-doped p-BaSi2 with H incorporation. The effect that atomic H had on the performance of B-doped p-BaSi2/n-Si heterojunction solar cells was also studied. The saturation current density was found to decrease by three orders of magnitude with the atomic H supply, and the conversion efficiency was increased up to 6.2%. Deep-level transient spectroscopy revealed a reduction of defect densities induced by the atomic H supply. Both experimental and theoretical viewpoints show that an atomic H supply is beneficial for BaSi2 solar cells.
Effect of laser polarization and target location on acceleration of electrons generated during ionization of gases by a laser pulse
Authors: Singh Kunwar Pal , Malik Anil K. , Sharma Jyotsna , Yadav Meena
Published: June 2020

We investigate the effect of the target position, laser polarization, and focusing on the energy spread and the angle of emittance for the acceleration of electrons generated during the ionization of rarefied gases, neon ions Ne8+, krypton ions Kr32+, and argon ions Ar16+ by a laser pulse. The electrons generated from the ions at the position after laser focus interact with the laser pulse for a longer duration and gain more energy than those electrons generated from the ions at the position before laser focus. There are two peaks in the energy spectrum for linear polarization and only one peak for circular polarization. The energy spectrum peak is sharper for circular polarization than that for linear polarization. The energy gained by the electrons increases with the laser spot size due to the increase in the laser energy. The spectrum of the angle of emittance for electrons shows the sharpest peak at the lowest angle for linear polarization for ions at the position after laser focus. The circular polarization is good to obtain quasi-monoenergetic electron beams and linearly polarized laser pulse is good to generate collimated electron beams. The required laser intensity to ionize electrons from the ions Ne8+, Kr32+, and Ar16+ increases and the electron energy peaks are at higher energies and scattering angles are at lower values for these gases, in their respective orders.
Effect of gas mixture on temperature and mass streaming in a phase-change thermoacoustic engine
Authors: Brustin Tom , Offner Avshalom , Ramon Guy Z.
Published: June 2020

Wet thermoacoustic engines (WTEs) are simple, robust energy conversion devices that employ a condensable vapor to generate acoustic power from heat. While previous studies focused on the potential of WTE technology to convert low-grade heat to power, this work focuses on the WTE's dependence on the working gas mixture, unique mass transport, and low working temperature properties, which make it a potential candidate for thermally driven separation processes, e.g., distillation and water desalination. In a set of experiments, the steady-state behavior of a water-based, standing-wave WTE was studied. The results highlight a remarkable trait of this system—a WTE is capable of producing a substantial flux of water vapor while exhibiting an operating hot-side temperature significantly lower than the boiling point. This “limiting temperature” is independent of the heat input to the system—theoretically predicted in systems that have no external “load” that consumes the acoustic power. In addition, the results suggest that the characteristics of the working gas play an important role in determining the device behavior. It was shown that in the tested range, a heavier, more complex-structured gas has significantly improved the steady-state performance of the engine. Specifically, a WTE working with SF6 as its working gas exhibited a vapor mass flux nearly three times greater than simple evaporation at the same heating power while maintaining a temperature as low as 57 °C. The link between gas characteristics and engine behavior is outlined. In conclusion, potential applications of the device and future research avenues are discussed.
Non-modal stability analysis in viscous fluid flows with slippery walls
Authors: Samanta Arghya
Published: June 2020

A study of optimal temporal and spatial disturbance growths is carried out for three-dimensional viscous incompressible fluid flows with slippery walls. The non-modal temporal stability analysis is performed under the framework of normal velocity and normal vorticity formulations. A Chebyshev spectral collocation method is used to solve the governing equations numerically. For a free surface flow over a slippery inclined plane, the maximum temporal energy amplification intensifies with the effect of wall slip for the spanwise perturbation, but it attenuates with the wall slip when perturbation considers both streamwise and spanwise wavenumbers. It is found that the boundary for the regime of transient growth appears far ahead of the boundary for the regime of exponential growth, which raises a question on the critical Reynolds number for the shear mode predicted from the eigenvalue analysis. Furthermore, the eigenvalue analysis or the modal stability analysis reveals that the unstable region for the shear mode decays rapidly in the presence of wall slip, which is followed by the successive amplification of the critical Reynolds number for the shear mode and ensures the stabilizing effect of slip length on the shear mode. On the other hand, for a channel flow with slippery bounding walls, the maximum spatial energy amplification intensifies with the effect of wall slip in the absence of angular frequency, but it reduces with the wall slip if the angular frequency is present in the disturbance. Furthermore, the maximum spatial energy disturbance growth can be achieved if the disturbance excludes the angular frequency. Furthermore, it is observed that the angular frequency plays an essential role in the pattern formation of optimal response. In addition, the pseudo-resonance phenomenon occurs due to external temporal and spatially harmonic forcings, where the pseudo-resonance peak is much higher than the resonance peak.
Thermal degradation of p-doped organic homojunction
Authors: Choi Hyun-Kyung , Lee Seung-Hun , Lim Young-Ji , Lee Seung-Taek , Lee Jeong-Hwan , Lee Jae-Hyun
Published: June 2020

The stability of doped organic semiconductors is one of the essential features to achieve stable and high-performance organic optoelectronic devices with low power consumption. In this study, the thermal degradation of an organic homojunction, consisting of an intrinsic organic layer and a molybdenum oxide (MoO3)-doped organic layer, is investigated by impedance spectroscopy (IS) under thermal heating. The IS analysis indicates that the thermal deformation of the intrinsic organic layer is more significant than that of the underlying doped organic layer. A charge-transfer complex absorption peak analysis by ultraviolet-visible spectroscopy confirms that the thermal degradation is related to the deformation of organic host molecules rather than to diffusion of dopants. These results show that the organic homojunction is degraded owing to the crystallization of intrinsic organic molecules at high temperatures, above the glass transition temperature (Tg), rather than because of disruption of the interface at the homojunction by dopant diffusion. This study shows that hole-transport molecules having high Tg should be selected to provide stable electronic devices with organic homojunctions, thus paving the way for the development of novel devices with higher performance.
The forecasting of COVID-19 with mortality using SIRD epidemic model for the United States, Russia, China, and the Syrian Arab Republic
Authors: Al-Raeei Marwan
Published: June 2020

In this paper, we apply an algorithm for simulating the susceptible-infected-recovered-dead pandemic model for demonstrating the forecasting and the spreading of the new coronavirus disease. For this purpose, we apply an implicit analytical solution for parts of the model, in addition to applying the finite difference methods for other parts of the model. Based on the collected data of the number of infected cases, recovered cases, and deceased cases of the new coronavirus pandemic as of 30 May 2020, we find the values of the coefficient of infection, the coefficient of recovery, and the coefficient of mortality of the new coronavirus pandemic for four different countries, namely, China, the United States, Russia, and the Syrian Arab Republic. Besides, we find the ratio of the average rate of recovery to the average rate of death of the new coronavirus pandemic for the same four countries. For the following months, we predict the number of the infected cases, the recovered cases, and the deceased cases of the pandemic for the United States, Russia, and the Syrian Arab Republic using the methods normally used for the epidemic model. We find that the number of infected cases of the new coronavirus disease may increase to about two million cases in the United States, about eight hundred thousand cases in Russia, and about three hundred cases in the Syrian Arab Republic. We believe that the algorithm we use for simulating the spreading and the forecasting of the new coronavirus disease can be applied for finding other related coefficients of the pandemic such as the basic reproduction numbers with a certain population.
Fluorescence Enhancement Method for Enrofloxacin Extraction by Core–Shell Magnetic Microspheres
Authors: Yang Linyan , Fu Leiming , Li Boxin , Ma Jifei , Li Cun , Jin Tianming , Gu Wen
Published: June 2020

In this work, we present novel kinds of γ-Fe2O3@SiO2-NH2-CMC/MOF5 and γ-Fe2O3@SiO2-NH2-CMC/IRMOF3 magnetic metal–organic framework (MOF) nanoparticles which possess both magnetic characteristics and fluorescent properties. Here, [Zn4O(bdc)3] (MOF-5, bdc=1,4-benzenedicarboxylate) is a kind of shell. IRMOF3, a known MOF with a cubic topology prepared from Zn(NO3)2⋅4H2O and 2-amino-1,4-benzene dicarboxylic acid, is another kind of shell which is attractive due to its highly porous, crystalline structure and the presence of non-coordinating amino groups on the benzenedicarboxylate (bdc) linker, which are amenable to post-synthetic modification. γ-Fe2O3@SiO2-NH2-CMC magnetic nanoparticles (MNPs) could be prepared by covalent modification of sodium carboxymethyl cellulose (CMC). The structure of γ-Fe2O3 nanoparticles could be determined by X-ray powder diffraction (XRD). X-ray photoelectron spectroscopy (XPS) spectra could be used for the characterisation of γ-Fe2O3@SiO2-NH2, γ-Fe2O3@SiO2-NH2-CMC, γ-Fe2O3@SiO2-NH2-CMC/MOF5, and γ-Fe2O3@SiO2-NH2-CMC/IRMOF3 nanoparticles. Magnetic solid-phase extraction (MSPE) of enrofloxacin (Enr) experiments exhibited that, for γ-Fe2O3@SiO2-NH2-CMC/IRMOF3, the best effects of adsorption could be obtained at pH 4 and 6, while elution conditions of 0.1mol L−1 NaOH and 1% sodium dodecyl sulfate could achieve the best elution effect. The addition of Tb3+ ions could sensitise the fluorescence of Enr. At the same time, via the addition of Tb3+ ions, coordination could occur between nanoparticles and Tb3+ ions, which could be verified by XPS.
Synthesis and Characterisation of Two Lithium Tetramethylberyllate Salts and a Series of β-Diketiminato Beryllium Alkyl Complexes
Authors: Paparo Albert , de Bruin-Dickason Caspar N. , Jones Cameron
Published: June 2020

A safer route than that previously published for the synthesis of [BeI2(OEt2)2] has been developed. Reactions of beryllium dihalide complexes [BeX2(OEt2)2] (X=Br or I) with either LiMe or LiBun lead to mixtures of products, which have been shown to act as sources of ‘BeR2’ (R=Me or Bun) in previous synthetic studies. Here, a titration method has been developed to determine the quantity of metal alkyl residues in these ‘BeR2’ mixtures that are available for subsequent alkane elimination reactions. Treating ‘BeMe2’ mixtures with N,N,N′,N′-tetramethylethylenediamine (tmeda) gave two lithium tetramethylberyllate compounds, [{(tmeda)Li}2(μ-BeMe4)] and [{[(tmeda)Li](BeMe4)(μ-Li)}∞], which were crystallographically characterised. Treatment of insitu-generated ‘BeR2’ solutions with several β-diketimines (HC{C(Me)=NR}{=C(Me)N(H)R}, NacnacH, R=aryl or alkyl) yielded a series of β-diketiminato beryllium alkyl complexes, [(Nacnac)BeR], including the first chiral example of such a compound. Crystallographic studies of these reveal them to be monomeric, with planar three-coordinate beryllium centres.
LED lights increase an antioxidant capacity of Arabidopsis thaliana under wound-induced stresses
Authors: Mirzahosseini Zahra , Shabani Leila , Sabzalian Mohammad R.
Published: June 2020

A comparison among four light emitting diode (LED) lights including red LED (R), blue LED (B), red (70%) + blue (30%) LED (RB) and white LED (W) as well as fluorescent (F) light was made on antioxidative capacity of Arabidopsis thaliana (L.) Heynh. in response to wounding. Under wound-stress condition, LED-exposed plants, especially RB-irradiated plants, maintained significantly higher shoot dry weight and antioxidant enzymes activities compared with those irradiated with fluorescent lights. The highest amounts of both chlorophyll a and b were observed in the leaves treated with B light. Also, the concentration of H2O2 was higher under the condition of RB and B lights compared with the other light environments. The highest amount of malondialdehyde was measured in plants exposed to F and B lights. Similarly, wounded leaves under F and B light conditions showed the maximum lipoxygenase activity, whereas R-exposed leaves had the lowest lipoxygenase activity. In contrast, the highest level of phenolic compounds was found in R and RB exposed leaves in response to wounding. Among the five light treatments, RB and B lights were more effective in stimulating anthocyanin synthesis; however, RB-exposed plants were more efficient in the late-induction of the PAL gene (phenylalanine ammonia lyase catalyses the first step of the general phenylpropanoid pathway). Collectively, we reasoned that RB light condition gives a superior capacity to Arabidopsis thaliana to tolerate wound-stress. Also, we propose the probable signalling role of ROS in light-stimulated wound responses in Arabidopsis.
Primordial emergence of a nucleic acid-binding protein via phase separation and statistical ornithine-to-arginine conversion
Authors: Longo Liam M. , Despotović Dragana , Weil-Ktorza Orit , Walker Matthew J. , Jabłońska Jagoda , Fridmann-Sirkis Yael , Varani Gabriele , Metanis Norman , Tawfik Dan S.
Published: June 2020

Significance

The first proteins emerged some 4 billion y ago, and understanding how they came about is a daunting challenge. Further complicating matters, the rules of protein structure and function derived from modern proteins may be irrelevant to their earliest ancestors. We report an integrated approach in which protein sequence, structure, and function are considered. We show that a simple function (phase separation) may have served as the basis for a complex function (specific double-stranded DNA binding), and that disordered polypeptides can give rise to structured, well-packed domains. Finally, we demonstrate that functional proteins may arise from short and simple sequences that include ornithine, an amino acid likely present in early proteins yet absent in modern proteins.
A wealth of genotype-specific proteoforms fine-tunes hemoglobin scavenging by haptoglobin
Authors: Tamara Sem , Franc Vojtech , Heck Albert J. R.
Published: June 2020

Significance

Haptoglobin (Hp) is one of the most abundant plasma proteins; it binds with high affinity to hemoglobin (Hb). Thereby Hp protects against the toxic effects of the heme when Hb leaks into plasma from damaged red blood cells. Therefore, serum Hp is an important antioxidant and a clinically important protein, often used as a protein biomarker. Here, we address in detail what proteoforms and proteoform assemblies co-occur in serum, and show how they differ in individuals with distinct genotypes. Our data, obtained by a range of state-of-the-art analytical methods, reveal in unprecedented detail how these hundreds of Hp proteoforms influence the scavenging of Hb through several distinctive molecular features of Hp genotypes.
A role for NPY-NPY2R signaling in albuminuric kidney disease
Authors: Lay Abigail C. , Barrington A. Fern , Hurcombe Jenny A. , Ramnath Raina D. , Graham Mark , Lewis Philip A. , Wilson Marieangela C. , Heesom Kate J. , Butler Matthew J. , Perrett Rebecca M. , Neal Chris R. , Herbert Eleanor , Mountjoy Edward , Atan Denize , Nair Viji , Ju Wenjun , Nelson Robert G. , Kretzler Matthias , Satchell Simon C. , McArdle Craig A. , Welsh Gavin I. , Coward Richard J. M.
Published: June 2020

Significance

Neuropeptide Y (NPY) is implicated in many pathological conditions including obesity, diabetes, and insulin resistance. However, a pathogenic role of NPY in kidney disease has not been described. We found that
NPY
is produced by the podocyte in the glomerulus, and this production decreases in renal disease, in contrast to an increase in circulating NPY levels. In the glomerulus, NPY signals via the NPY receptor 2 (NPY2R) and modulates PI3K, MAPK, and NFAT signaling, along with RNA processing and cell migration and, if prolonged, predicted nephrotoxicity. The pharmacological inhibition of NPY-NPY2R signaling also protected against albuminuria and kidney disease in a mouse model of glomerulosclerosis, suggesting that inhibiting this pathway may be therapeutically beneficial in the prevention of kidney disease.
Afrikaans circumpositions
Authors: Pretorius Erin
Published: June 2020

Circumpositions in Afrikaans present several puzzles: (i) they always encode spatial paths, but spatial paths can also be encoded by prepositional phrases; (ii) they can be doubling or non-doubling, and (iii) they exhibit disharmonic word order of the kind that appears to violate the Final-over-Final Condition (FOFC). In this paper, I argue that circumpositions offer support for the existence of a directional head [dir] in the fine structure of the Afrikaansverbal domain, and that this head is lexicalised by adpositional material in circumpositional expressions. I show that Afrikaans grammar distinguishes Route-paths from Goal-/Source-paths, and argue that whereas [dir] selects a [pathP] in the structure underlying Goal-/Source-paths (circumpositional expressions), Route-paths (prepositional expressions) are ‘bare’ [pathP] structures. I argue that since circumpositions identify structural components in different Spellout Domains, double-insertion of adposition-like material is required to exhaustively lexicalise the structure, and the disharmonic word order is understood as a direct consequence of the fact that [dir] is located in Afrikaans’ head-final verbal, which addresses the concern arising around FOFC. Finally, given that the adpositions in circumpositional expressions are shown to occupy structural positions that are distinct from that of de-adpositional V-particles, the paper also addresses the structural relation between circumpositions and particle verbs in which adposition-like material lexicalises a resultative [res] node in the verbal domain.
Design of experiment (DoE)‐driven in vitro and in vivo uptake studies of exosomes for pancreatic cancer delivery enabled by copper‐free click chemistry‐based labelling
Authors: Xu Lizhou , Faruqu Farid N. , Liam‐or Revadee , Abu Abed Omar , Li Danyang , Venner Kerrie , Errington Rachel J , Summers Huw , Wang Julie Tzu‐Wen , Al‐Jamal Khuloud T.
Published: June 2020

Exosomes (Exo)‐based therapy holds promise for treatment of lethal pancreatic cancer (PC). Limited understanding of key factors affecting Exo uptake in PC cells restricts better design of Exo‐based therapy. This work aims to study the uptake properties of different Exo by PC cells. Exo from pancreatic carcinoma, melanoma and non‐cancer cell lines were isolated and characterised for yield, size, morphology and exosomal marker expression. Isolated Exo were fluorescently labelled using a novel in‐house developed method based on copper‐free click chemistry to enable intracellular tracking and uptake quantification in cells. Important factors influencing Exo uptake were initially predicted by Design of Experiments (DoE) approach to facilitate subsequent actual experimental investigations. Uptake of all Exo types by PC cells (PANC‐1) showed time‐ and dose‐dependence as predicted by the DoE model. PANC‐1 cell‐derived exosomes (PANC‐1 Exo) showed significantly higher uptake in PANC‐1 cells than that of other Exo types at the longest incubation time and highest Exo dose. In vivo biodistribution studies in subcutaneous tumour‐bearing mice similarly showed favoured accumulation of PANC‐1 Exo in self‐tissue (i.e. PANC‐1 tumour mass) over the more vascularised melanoma (B16‐F10) tumours, suggesting intrinsic tropism of PC‐derived Exo for their parent cells. This study provides a simple, universal and reliable surface modification approach via click chemistry for in vitro and in vivo exosome uptake studies and can serve as a basis for a rationalised design approach for pre‐clinical Exo cancer therapies.
Why is physics hard? Unpacking students’ perceptions of physics
Authors: Bray A , Williams J
Published: June 2020

It has been well established that there are many challenges associated with physics teaching and learning. This pilot study attempted to identify the perceptions of first-year students studying physics at Rhodes University in 2017. Academics in the Department were interviewed, a questionnaire was created and a survey was conducted with first-year students. Emotional issues were identified as the largest contributing factor to students’ perceptions of physics. A high correlation between study skills and students’ understanding and problem-solving abilities was observed. Under-preparedness was recognised as an important issue that needs further investigation.
A review of the final and supplementary Grade 12 physics examinations from 2014 to 2018 based on a modified Bloom’s taxonomy.
Authors: Bhaw N , Kriek J
Published: June 2020

The South African National Department of Basic Education (DBE) has associated the poor pass rate in the National Senior Certificate (NSC) Physical Sciences to the learners’ lack of practical work and the inability to solve problems by integrating their knowledge from different topics in Physical Sciences. Given that the Curriculum and Assessment Policy Statement (CAPS) is central to the planning, organising and teaching of Physical Sciences, the poor performance in the Grade 12 Physical Sciences: Physics (P1) may be due to a disjointed alignment between the CAPS and the P1. A purposive sampling procedure included the CAPS Grades 10–12 Physical Sciences document; the Physical Sciences Examination Guidelines Grade 12 documents and the final and supplementary P1 examinations for the period starting November 2014 to March 2018. A summative content analysis research technique was conducted using the Surveys of Enacted Curriculum (SEC) research method. The SEC method employed the use of the four topics of Physics and the four non-hierarchical levels of cognitive demand as described in the modified version of Bloom’s taxonomy. The results of this study indicated that the CAPS had a higher proportion of recall based content than the P1, the CAPS, and the P1 had approximately equal proportions of comprehension based content, the CAPS had a lower proportion of application and analysis based content than the P1, and the CAPS, as well as the P1, did not contain any synthesis and evaluation based content. In terms of Bloom’s taxonomy, the CAPS may be classified as promoting lower order thinking skills, and the P1 may be classified as promoting higher order thinking skills.
Experimentation in primary school: discover and understand or verify what is expected?
Authors: Stari C , Haniotis S , Sguilla S
Published: June 2020

Science education in primary schools in Uruguay is still a pending task. Frequently, only biological science is taught in class. Often, activities are reduced either to look for information without experimentation, or to very guided hand-on activities with little space for actual research where results may differ from what is expected and new questions might come up. As a result, children have a partial and sometimes wrong concept of science. The idea of science as something distant from reality and ordinary life, holding absolute results and truth, is reinforced. A lot of research has been done in science didactics about the role of experimentation in order to improve scientific competences in the students. In this project we analyze the role of experimentation during the science class as well as the speech of the teacher in relation to his objectives and the planned didactic sequence. A qualitative methodology was used, through classroom observations and interviews with teachers. We chose a case study to inquire how the experiments are used in a science class and what is the role of experiments proposed by the teacher. To collect the data, recordings of classes were used and in-depth interviews were conducted with the teacher.
A comparative analysis of school physics curriculum content in selected countries
Authors: Ramaila S.
Published: June 2020

Meaningful curriculum reform is central to the provision and acquisition of globally relevant scientific skills. A globally competitive curriculum fosters the cultivation of skills required for sustainable economic growth and development. In addition, it is imperative to harness the affordances associated with the provision of intellectually stimulating school physics curriculum content in order to foster the development of cognitive and reflective skills. In response to this key imperative, a comparative analysis of school physics curriculum content in selected countries was carried out with a view to identify levels of commonalities and the depth up to which each curriculum extends. Comparative analysis of school physics curriculum content in selected countries revealed striking inherent characteristic features that serve to provide the structural differentiation between these curricula. The level of economic growth and development in selected countries appeared to be a function of the quality and depth of the school physics curriculum content. Theoretical implications for meaningful curriculum reform are discussed.