bluuebunny/crossref_metadata_2025 huggingface dataset:
Association study between HTR2A rs6313 polymorphism and early response to risperidone and olanzapine in schizophrenia patients
Authors: Maffioletti Elisabetta , Valsecchi Paolo , Minelli Alessandra , Magri Chiara , Bonvicini Cristian , Barlati Stefano , Sacchetti Emilio , Vita Antonio , Gennarelli Massimo
Published: May 2020

Antipsychotic drugs are the preferred choice for schizophrenia treatment; however, response is highly variable. In the context of the search for predictors of antipsychotic treatment effectiveness, the evaluation of response within 2 weeks has been indicated to predict long‐term outcome. Moreover, a focus on symptomatological domains could be helpful to better characterize antipsychotic response, identifying more specific predictors. Pharmacogenetic studies have indicated a role for rs6313 in the serotonin receptor gene HTR2A in affecting response to antipsychotics, with heterogeneous results. With the aim to test for the first time the application of a dimensional approach for the evaluation of early response, we carried out a genetic association study between rs6313 and antipsychotic response in two groups of schizophrenia patients in monotherapy with risperidone (n = 121) and olanzapine (n = 100). Patients were evaluated at the baseline and after 1 and 2 weeks of treatment. When comparing early responders versus early nonresponders, no association was detected for the two drugs separately, whereas by taking into consideration the two drugs together it was observed that carriers of the T allele had a higher response probability compared to noncarriers. Considering 2‐week improvements, changes in PANSS total scores, subscores and in PANSS Emsley's symptomatological dimensions were associated with rs6313 for both risperidone and olanzapine. Moreover, the repeated measures analysis indicated an association of rs6313 with the disorganized thought dimension for risperidone, and with the depressive and anxiety dimensions for olanzapine. These data add support to the hypothesis that the HTR2A gene is involved in antipsychotic treatment outcome.
60 specific eDNA qPCR assays to detect invasive, threatened, and exploited freshwater vertebrates and invertebrates in Eastern Canada
Authors: Hernandez Cecilia , Bougas Bérénice , Perreault‐Payette Alysse , Simard Anouk , Côté Guillaume , Bernatchez Louis
Published: May 2020

Practical applications of environmental DNA (eDNA) are in exponential expansion, especially for the assessment and monitoring of freshwater metazoans. Because eDNA sampling and analysis is noninvasive, it improves the detection of threatened, invasive, and exploited species for which monitoring may be challenging. Species detection efforts using a combination of eDNA and qPCR have been highly successful and, as a result, their use in species monitoring is expanding rapidly. We developed qPCR primers and probes in order to monitor many invasive, threatened, or exploited aquatic species as part of various monitoring eDNA projects in the province of Québec, Canada. Here, we present a total of 60 species‐specific qPCR assays (including PCR protocols, primers, and TaqMan probes sequences) developed for the detection of 45 fishes, six amphibians, five reptiles, two mollusks, and two crustaceans. These comprised nine and 27 species, respectively, listed as invasive and threatened in Eastern Canada. These resources should be of broad usefulness not only for monitoring studies based in Québec but throughout the geographic range of the targeted species in North America.
Study on induced stress of hydraulic fracturing in fractured‐porous elastic media
Authors: Hu Yongquan , Wang Qiang , Zhao Jinzhou , Chen Shengnan , Zhang Guiyi , Wang Sukai , Wang Zhiyong , Fu Chenghao
Published: May 2020

The study on induced stress of hydraulic fracturing is an important part of hydraulic fracturing design, temporary plugging and steering fracturing design, and completion design in oil and gas development. Based on fracture continuum method (FCM), cohesive unit method, and finite volume method (FVM), the propagation behavior of multiple hydraulic fractures (HFs) in fractured‐porous media reservoir is simulated from the perspective of fluid and geological stress coupling. The influence of natural fractures (NFs) on stress distribution and stress inversion sensitive factors are studied. NFs in the model are equivalent to physical models controlled by tension and shear bonds. The proposed model can deal with any number of NFs, which greatly improves the computational efficiency of the model. Then PKN analytic solution and Abaqus software results were used to verify the correctness of our model. The results show that the NF will make the reservoir stress show strong heterogeneity after fracturing, and the prominent feature is the regional stress mutation. The sudden change of stress shows the sudden increase or decrease in stress; with the increase in the initial stress difference, the stress inversion becomes more difficult. When the stress difference exceeds 3 MPa, the stress inversion area is almost 0. The stress interference increases with the decrease in cluster spacing. The stress inversion region between HFs decreases, while the external stress inversion region increases; Biot coefficient has great influence on stress and stress inversion. With the decrease in Biot coefficient, stress inversion region will decrease obviously. When the Biot coefficient is 0.4, there is no stress inversion area in the whole reservoir. Poisson's ratio has little influence on stress inversion. When Poisson's ratio changes between 0.1 and 0.3, the change range of stress is within 1 MPa, and the stress inversion area is almost unchanged. Our results can be helpful for understanding the stress distribution after hydraulic fracturing in fractured‐porous media.
Protective and Detrimental Roles of p38α Mitogen‐Activated Protein Kinase in Different Stages of Nonalcoholic Fatty Liver Disease
Authors: Hwang Seonghwan , Wang Xiaolin , Rodrigues Robim M. , Ma Jing , He Yong , Seo Wonhyo , Park Seol Hee , Kim Seung‐Jin , Feng Dechun , Gao Bin
Published: May 2020

Background and Aims

Neutrophil infiltration is a hallmark of nonalcoholic steatohepatitis (NASH), but how this occurs during the progression from steatosis to NASH remains obscure. Human NASH features hepatic neutrophil infiltration and up‐regulation of major neutrophil‐recruiting chemokines (e.g., chemokine [C‐X‐C motif] ligand 1 [CXCL1] and interleukin [IL]‐8). However, mice fed a high‐fat diet (HFD) only develop fatty liver without significant neutrophil infiltration or elevation of chemokines. The aim of this study was to determine why mice are resistant to NASH development and the involvement of p38 mitogen‐activated protein kinase (p38) activated by neutrophil‐derived oxidative stress in the pathogenesis of NASH.

Approach and Results

Inflamed human hepatocytes attracted neutrophils more effectively than inflamed mouse hepatocytes because of the greater induction of CXCL1 and IL‐8 in human hepatocytes. Hepatic overexpression of Cxcl1 and/or IL‐8 promoted steatosis‐to‐NASH progression in HFD‐fed mice by inducing liver inflammation, injury, and p38 activation. Pharmacological inhibition of p38α/β or hepatocyte‐specific deletion of p38a (a predominant form in the liver) attenuated liver injury and fibrosis in the HFD
+Cxcl1
‐induced NASH model that is associated with strong hepatic p38α activation. In contrast, hepatocyte‐specific deletion of p38a in HFD‐induced fatty liver where p38α activation is relatively weak exacerbated steatosis and liver injury. Mechanistically, weak p38α activation in fatty liver up‐regulated the genes involved in fatty acid β‐oxidation through peroxisome proliferator‐activated receptor alpha phosphorylation, thereby reducing steatosis. Conversely, strong p38α activation in NASH promoted caspase‐3 cleavage, CCAAT‐enhancer‐binding proteins homologous protein expression, and B cell lymphoma 2 phosphorylation, thereby exacerbating hepatocyte death.

Conclusions

Genetic ablation of hepatic p38a increases simple steatosis but ameliorates oxidative stress‐driven NASH, indicating that p38α plays distinct roles depending on the disease stages, which may set the stage for investigating p38α as a therapeutic target for the treatment of NASH.
Spectral relaxation method analysis of Casson nanofluid flow over stretching cylinder with variable thermal conductivity and Cattaneo–Christov heat flux model
Authors: Tulu Ayele , Ibrahim Wubshet
Published: May 2020

This article deals with non‐Newtonian Casson nanofluid flow and heat transfer over stretching cylinder in a porous medium. The mode of heat transfer is presented considering temperature‐dependent thermal conductivity by integrating the Cattaneo–Christov heat flux and mass flux models. Boundary layer theory is applied to develop the governing partial differential equations from the physical problem. Employing proper similarity transformation, the governing boundary layer equations are transformed into dimensionless system of nonlinear ordinary differential equations. Then, the resulting problem is numerically solved by means of spectral relaxation method. The convergence analysis of the proposed numerical scheme is presented via a table, which confirms almost the 10th order of approximation is enough for the convergence of the skin friction coefficient, local heat transfer, and mass transfer rates. The effects of various embedded parameters on velocity, temperature, and concentration profiles as well as skin friction coefficient, surface heat and mass transfer rates are examined through graphs and tables. The findings reveal that the growth of permeability and velocity slip parameters appears to decelerate the velocity distributions of fluid. Thermal boundary layer thickness tends to develop with greater values of permeability and Brownian motion parameters. Also, the local heat transfer rate is less with Fourier's law of heat conduction than Cattaneo–Christov heat flux model. Furthermore, the validity and accuracy of the present result is checked with the available literature, and very sound agreement has been obtained.
Numerical study of natural convection and acoustic waves using the lattice Boltzmann method
Authors: Benhamou Jaouad , Jami Mohammed , Mezrhab Ahmed , Botton Valéry , Henry Daniel
Published: May 2020

In this paper, the lattice Boltzmann method is used to study the acoustic waves propagation inside a differentially heated square enclosure filled with air. The waves are generated by a point sound source located at the center of this cavity. The main aim of this simulation is to simulate the interaction between the thermal convection and the propagation of these acoustic waves. The results have been validated with those obtained in the literature and show that the effect of natural convection on the acoustic waves propagation is almost negligible for low Rayleigh numbers (Ra ≤ 104), which begins to appear when the Rayleigh number begins to become important (Ra ≥ 105) and it becomes considerable for large Rayleigh numbers (Ra ≥ 106) where the thermal convection is important.
Progressive plasmacytoid variant bladder cancer with retroperitoneal dissemination: An autopsy case report
Authors: Kohada Yuki , Kaiho Yasuhiro , Ito Jun , Mikami Jotaro , Anan Go , Asano Katsutoshi , Yaegashi Toru , Murakami Kazuhiro , Nakamura Yasuhiro , Sato Makoto
Published: May 2020

Introduction

Plasmacytoid urothelial carcinoma is a rare and aggressive variant of bladder cancer.

Case presentation

A 75‐year‐old woman presented with plasmacytoid urothelial carcinoma with retroperitoneal dissemination was treated with chemotherapy. After an unsuccessful first‐line chemotherapy with gemcitabine and cisplatin, we assessed circulating tumor cells; one such cell was found to be positive for programmed death‐ligand 1. The patient received second‐line chemotherapy with pembrolizumab. However, the tumor extended to the retroperitoneal organs, and the patient eventually died. Autopsy revealed a widespread diffuse scirrhous infiltration of the carcinoma into the retroperitoneum. However, distant metastasis was not observed.

Conclusion

The evaluation of circulating tumor cells and autopsy revealed a disease state of progressive plasmacytoid urothelial carcinoma treated with pembrolizumab.
Response to Bistrian BR. Parenteral Fish‐Oil Emulsions in Critically Ill COVID‐19 Emulsions
Authors: Torrinhas Raquel S. , Calder Philip C. , Waitzberg Dan L.
Published: May 2020

In this letter we discuss the proposition of Bristian BR (2020) to use the intravenous administration of fish‐oil emulsions in critically ill patients with Coronavirus Disease 2019 (COVID‐19). We consider that immune‐modulatory properties of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, rapidly provided in high amounts by fish‐oil emulsions, may be important to change the course of COVID‐19's death pathway. Prescriptions should be based on body weight (eg, 0.2‐g pure fish‐oil lipid emulsion/kg body weight/d) and also should consider combining the parenteral administration of fish‐oil emulsions with low oral aspirin intake to trigger resolvin synthesis from EPA and DHA.
Should adenosquamous esophageal cancer be treated like adenocarcinoma or squamous cell carcinoma?
Authors: Gamboa Adriana C. , Meyer Benjamin I. , Switchenko Jeffrey M. , Rupji Manali , Lee Rachel M. , Turgeon Michael K. , Russell Maria C. , Cardona Kenneth , Kooby David A. , Maithel Shishir K. , Shah Mihir M.
Published: May 2020

Background

Esophageal adenocarcinoma (AC) and squamous cell carcinoma (SCC) have distinct outcomes, treatment strategies, and response profiles to therapy. Adenosquamous carcinoma (ASC) is thought to behave more aggressively than each of its counterparts. The aim of this study is to determine ifASC is best managed as AC or SCC.

Methods

National Cancer Database (2004‐2015) was queried for patients with nonmetastatic esophageal ASC. The analysis was stratified by clinical node‐negative (cN0) or clinical node‐positive (cN1‐3). Treatment was categorized into chemoradiation alone, surgery alone, or preoperative chemoradiation followed by surgery. The primary outcome was 5‐year overall survival (OS).

Results

Among 352 patients, 43% were cN0 (n = 151), 57% were cN1‐3 (n = 201) and 55% had chemoradiation alone (n = 194), 15% surgery alone (n = 53), and 30% preoperative chemoradiation (n = 105). Among patients who had preoperative chemoradiation, 20% had pathologic complete response (n = 17). For either cN0 or cN1‐3, Charlson‐Deyo Comorbidity Index did not differ among the treatment groups(all p > 0.05). On Kaplan‐Meier analysis for cN0, treatment with surgery alone had comparable OS to preoperative chemoradiation (47% vs 34%; P = .5) and each had improved OS compared to chemoradiation alone (30%; P = .02; P = .06). On univariate analysis for cN0, clinical T category was not associated with OS. For cN1‐3, however, preoperative chemoradiation was associated with improved OS when compared to chemoradiation alone or surgery alone (27% vs 19% vs 0%; P < .001). This persisted when accounting for age and clinical T category (hazard ratio: 0.45; P < .001).

Conclusion

Esophageal ASC behaves more like AC in response to chemoradiation and survival based on treatment modality. A complete response to chemoradiation is only 20% unlike what has been shown for SCC, where chemoradiation is an acceptable definitive therapy. Esophageal ASC should be managed more like AC.
On a multiple credit rating migration model with stochastic interest rate
Authors: Huang Zhehao , Jiang Tianpei , Wang Zhenzhen
Published: May 2020

In this paper, we explore a pricing model for corporate bond accompanied with multiple credit rating migration risk and stochastic interest rate. The bond price volatility strongly depends on potentially multiple credit rating migration and stochastic change of interest rate. A free boundary problem of partial differential equation is presented, which is the equivalent transformation of the pricing model. The existence, uniqueness, and regularity for the free boundary problem are established to guarantee the rationality of the pricing model. Due to the stochastic change of interest rate, the discontinuous coefficient in the free boundary problem depends explicitly on the time variable but is convergent as time tends to infinity. Accordingly, an auxiliary free boundary problem is constructed, whose coefficient is the convergent limit of the coefficient in the original free boundary problem. With some constraint on the risk discount rate satisfied, we prove that a unique traveling wave exists in the auxiliary free boundary problem. The inductive method is adopted to fit the multiplicity of credit rating. Then we show that the solution of the original free boundary problem converges to the traveling wave in the auxiliary free boundary problem. Returning to the pricing model with multiple credit rating migration and stochastic interest rate, we conclude that the bond price profile can be captured by a traveling wave pattern coupling with a guaranteed bond price with face value equal to one at the maturity.
Efficient 23Na triple‐quantum signal imaging on clinical scanners: Cartesian imaging of single and triple‐quantum 23Na (CRISTINA)
Authors: Hoesl Michaela A. U. , Schad Lothar R. , Rapacchi Stanislas
Published: May 2020

Purpose

To capture the multiquantum coherence (MQC) 23Na signal. Different phase‐cycling options and sequences are compared in a unified theoretical layout, and a novel sequence is developed.

Methods

An open source simulation overview is provided with graphical explanations to facilitate MQC understanding and access to techniques. Biases such as B0 inhomogeneity and stimulated echo signal were simulated for 4 different phase‐cycling options previously described. Considerations for efficiency and accuracy lead to the implementation of a 2D Cartesian single and triple quantum imaging of sodium (CRISTINA) sequence employing two 6‐step cycles in combination with a multi‐echo readout. CRISTINA was compared to simultaneous single‐quantum and triple‐quantum‐filtered MRI of sodium (SISTINA) under strong static magnetic gradient. CRISTINA capabilities were assessed on 8 × 60 mL, 0% to 5% agarose phantom with 50 to 154 mM 23Na concentration at 7 T. CRISTINA was demonstrated subsequently in vivo in the brain.

Results

Simulation of B0 inhomogeneity showed severe signal dropout, which can lead to erroneous MQC measurement. Stimulated echo signal was highest at the time of triple‐quantum coherences signal maximum. However, stimulated echo signal is separated by Fourier Transform as an offset and did not interfere with MQC signals. The multi‐echo readout enabled capturing both single‐quantum coherences and triple‐quantum coherences signal evolution at once. Signal combination of 2 phase‐cycles with a corresponding B0 map was found to recover the signal optimally. Experimental results confirm and complement the simulations.

Conclusion

Considerations for efficient MQC measurements, most importantly avoiding B0 signal loss, led to the design of CRISTINA. CRISTINA captures triple‐quantum coherences and single‐quantum coherences signal evolution to provide complete sodium signal characterization including

fast,

slow, MQC amplitudes, and sodium concentration.
Uninformed decision‐making and regret about delaying childbearing decisions: A cross‐sectional study
Authors: Adachi Tomoko , Endo Masayuki , Ohashi Kazutomo
Published: May 2020

Aim

The aim of this study was to examine regret over the timing of the childbearing decision and reasons for its delay.

Design

A cross‐sectional study.

Methods

This cross‐sectional study included 219 women and 169 men referred to fertility facilities in Japan from July–December 2018. Participants completed a questionnaire on the reasons for their delay in childbearing decision and the degree of regret regarding their decision. Multiple linear regression was used to analyse the association between degree of regret and the reasons for the delay.

Results

The top three reasons for the delay in childbearing decision in women were “Establishing the relationship,” “Health problems,” and “Financial security.” The top three reasons in men were “Establishing the relationship,” “Financial security,” and “Lack of fertility knowledge.” Multiple linear regression showed that lack of fertility knowledge was associated with regret over the timing of childbearing decisions in women and men.
Adhesion between thermoplastic elastomers and polyamide‐12 with different glass fiber fractions in two‐component injection molding
Authors: Persson Anna‐Maria M. R. , Hinrichsen Einar L. , Andreassen Erik
Published: May 2020

The usage of thermoplastic elastomers (TPEs) is increasing, and integrated hard‐soft parts can be mass produced by two‐component injection molding (or sequential molding). A key property of such parts, the adhesion between the two materials, is the topic of this study. The hard part (the first molded component) in this study was polyamide‐12 with 0 to 50 wt% glass fibers (PA12‐GF). As the second component, two TPEs were used: a vulcanized TPE and a styrenic TPE, both modified for adhesion to polyamides. The adhesion, assessed by 90° peel tests, increased with increasing melt temperatures and TPE injection rate, while it decreased with increasing glass fiber fraction in the PA12‐GF. Based on characterization of cross‐sections and fiber distributions near the interface, we propose some hypotheses for the effect of fiber fraction on the fusion between PA12‐GF and TPE. These hypotheses involve the near‐surface properties of the PA12‐GF materials, microstructure, thermo‐mechanical properties, and thermal properties. A direct effect of increasing the glass fiber fraction, that is, a reduction in adhesion as more fibers are present at the interface, does not seem to be a major effect, since few fibers are in direct contact with the TPE for any fiber fraction.
Shortlisting SARS‐CoV‐2 Peptides for Targeted Studies from Experimental Data‐Dependent Acquisition Tandem Mass Spectrometry Data
Authors: Gouveia Duarte , Grenga Lucia , Gaillard Jean‐Charles , Gallais Fabrice , Bellanger Laurent , Pible Olivier , Armengaud Jean
Published: May 2020

Detection of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is a crucial tool for fighting the COVID‐19 pandemic. This dataset brief presents the exploration of a shotgun proteomics dataset acquired on SARS‐CoV‐2 infected Vero cells. Proteins from inactivated virus samples were extracted, digested with trypsin, and the resulting peptides were identified by data‐dependent acquisition tandem mass spectrometry. The 101 peptides reporting for six viral proteins were specifically analyzed in terms of their analytical characteristics, species specificity and conservation, and their proneness to structural modifications. Based on these results, a shortlist of 14 peptides from the N, S, and M main structural proteins that could be used for targeted mass‐spectrometry method development and diagnostic of the new SARS‐CoV‐2 is proposed and the best candidates are commented.
RAFT polymerization of tertiary sulfonium zwitterionic monomer in aqueous media for synthesis of protein stabilizing double hydrophilic block copolymers
Authors: Imamura Ryutaro , Masuko Kazunori , Mori Hideharu
Published: May 2020

The reversible addition‐fragmentation chain‐transfer (RAFT) polymerization of a tertiary sulfonium‐containing zwitterionic monomer (N‐acryloyl‐L‐methionine methyl sulfonium salt: A‐Met[S+]‐OH) was performed in aqueous media in the presence of a water‐soluble chain‐transfer agent (CTA). Several parameters, such as the radical initiator, nature of the salt used as an additive, polymerization temperature, and solvent (water, buffer solution, and mixed solvents), were studied. The polymerization of A‐Met(S+)‐OH in acetate buffer using a trithiocarbonate‐type CTA having two carboxylic acid moieties proceeded in a controlled fashion at 45°C, as confirmed by the low polydispersity of the products (M
w/M
n < 1.1) and pre‐determined molecular weights. Poly(ethylene glycol)‐based macro‐CTA was also employed for the polymerization of A‐Met(S+)‐OH in mixed solvents (H2O/EtOH and H2O/DMF = 70/30 vol%) to afford novel nonionic‐zwitterionic double hydrophilic block copolymers. The chain extension of the hydrophilic poly(N,N‐dimethylacrylamide) macro‐CTA with A‐Met(S+)‐OH was well controlled in pure water under the appropriate conditions, resulting in the formation of block copolymers with “as‐designed” chain structures and relatively low dispersities (M
w/M
n < 1.3). The resulting sulfonium‐containing double hydrophilic block copolymers having optimal nonionic/zwitterionic balance were efficient protein‐stabilizing agents.
Design of a surrogate Anticalin protein directed against CD98hc for preclinical studies in mice
Authors: Deuschle Friedrich‐Christian , Schiefner André , Brandt Corinna , Skerra Arne
Published: May 2020

The human CD98 heavy chain (CD98hc) offers a promising biomedical target both for tumor therapy and for drug delivery to the brain. We have previously developed a cognate Anticalin protein with picomolar affinity and demonstrated its effectiveness in a xenograft animal model. Due to the lack of cross‐reactivity with the murine ortholog, we now report the development and X‐ray structural analysis of an Anticalin with high affinity toward CD98hc from mouse. This binding protein recognizes the same protruding epitope loop—despite distinct structure—in the membrane receptor ectodomain as the Anticalin selected against human CD98hc. Thus, this surrogate Anticalin should be useful for the preclinical assessment of CD98hc targeting in vivo and support the translational development for medical application in humans.
Towards autonomous inspection of concrete deterioration in sewers with legged robots
Authors: Kolvenbach Hendrik , Wisth David , Buchanan Russell , Valsecchi Giorgio , Grandia Ruben , Fallon Maurice , Hutter Marco
Published: May 2020

The regular inspection of sewer systems is essential to assess the level of degradation and to plan maintenance work. Currently, human inspectors must walk through sewers and use their sense of touch to inspect the roughness of the floor and check for cracks. The sense of touch is used since the floor is often covered by (waste) water and biofilm, which renders visual inspection very challenging. In this paper, we demonstrate a robotic inspection system which evaluates concrete deterioration using tactile interaction. We deployed the quadruped robot ANYmal in the sewers of Zurich and commanded it using shared autonomy for several such missions. The inspection itself is realized via a well‐defined scratching motion using one of the limbs on the sewer floor. Inertial and force/torque sensors embedded within specially designed feet captured the resulting vibrations. A pretrained support vector machine (SVM) is evaluated to assess the state of the concrete. The results of the classification are then displayed in a three‐dimensional map recorded by the robot for easy visualization and assessment. To train the SVM we recorded 625 samples with ground truth labels provided by professional sewer inspectors. We make this data set publicly available. We achieved deterioration level estimates within three classes of more than 92% accuracy. During the four deployment missions, we covered a total distance of 300 m and acquired 130 inspection samples.
Scandium(III) Trifluoromethanesulfonate Catalyzed Reactions of 9‐Aryl‐9‐fluorenols with 1,1‐Diarylethylenes
Authors: He. Yuchen , Tang Zhicong , Hong Gang , Hu Chen , Zhou Chen , Wang Limin
Published: May 2020

A new efficient approach to highly substituted fluorenes has been presented by reacting 9‐aryl‐9‐fluorenols with 1,1‐diarylethylenes. These reactions were catalyzed by Sc(OTf)3 and provided a wide variety of the corresponding products in excellent yields (up to 99 % yield). In addition, the initial photophysical property evaluation of certain products may inspire the development of potential OLEDs materials.
Trace analysis of potential genotoxic impurity N,N‐dimethylaniline in linagliptin active pharmaceutical ingredient using HPLC
Authors: Al‐Sabti Bashar , Harbali Jehad
Published: May 2020

The aim of this study was to develop an analytical method to determine the quantity of potential genotoxic impurity N,N‐dimethylaniline, a reactive reagent in the synthesis of linagliptin. The sensitivity of the method was high at a level of 0.9 ppm of N,N‐dimethylaniline relative to linagliptin. The analyses were performed on a KROMASIL CN (250 mm × 3.9 mm, 3.5 μm) column in reversed phase mode using acetonitrile–water (75:25, v/v) containing 25.0 mM ammonium acetate as the mobile phase. Flow rate of the mobile phase was 1.0 mL/min. A UV detector was used to detect the amount of N,N‐dimethylaniline at a wavelength 254 nm. Validation of the method was performed as per the International Council for Harmonization guidelines in terms of detection limit, quantitation limit, linearity, precision, accuracy, specificity, and robustness. The linearity of the method was excellent in the range of 0.9–450 ppm with a correlation coefficient of 0.9999. This method showed an excellent sensitivity with a detection limit and quantitation limit of 0.3 and 0.9 ppm, respectively.
Oxidorhenium(V) and Rhenium(III) Complexes with m‐Terphenyl Isocyanides
Authors: Figueroa Joshua S. , Abram Ulrich
Published: May 2020

Reactions of the sterically encumbered m‐terphenyl isocyanides CNArDipp2 (Dipp = 2,6‐diisopropylphenyl) and CNArMes2 (Mes = 2,4,6‐trimethylphenyl) with (NBu4)[ReOCl4] in CH2Cl2 form stable complexes of the composition (NBu4)[ReOCl3(CNArR)] or [ReOCl3(CNArR)2] depending on the amount of isocyanide added. In the [ReOCl3(CNArR)2] complexes, cis coordination of the two isocyanides is observed for CNArMes2, while the sterically more demanding CNArDIPP2 ligands are found in trans positions. The rhenium(III) species [ReCl3(PPh3)(CNArMes2)2] was obtained from the reaction of [ReOCl3(PPh3)2] and CNArMes2. The ν(CN) IR frequencies measured for the ReV complexes appear at higher wavenumbers than for the uncoordinated isocyanides, which suggests a low degree of backdonation into anti‐bonding orbitals of these ligands.
Singular solutions in soft limits
Authors: Cachazo Freddy , Umbert Bruno , Zhang Yong
Published: May 2020

Abstract

A generalization of the scattering equations on X (2, n), the configuration space of n points on ℂℙ1, to higher dimensional projective spaces was recently introduced by Early, Guevara, Mizera, and one of the authors. One of the new features in X (k, n) with k > 2 is the presence of both regular and singular solutions in a soft limit. In this work we study soft limits in X (3, 7), X (4, 7), X (3, 8) and X (5, 8), find all singular solutions, and show their geometrical configurations. More explicitly, for X (3, 7) and X (4, 7) we find 180 and 120 singular solutions which when added to the known number of regular solutions both give rise to 1 272 solutions as it is expected since X (3, 7) ∼ X (4, 7). Likewise, for X (3, 8) and X (5, 8) we find 59 640 and 58 800 singular solutions which when added to the regular solutions both give rise to 188 112 solutions. We also propose a classification of all configurations that can support singular solutions for general X (k, n) and comment on their contribution to soft expansions of generalized biadjoint amplitudes.
Selective laser melting (SLM) of AISI 316L—impact of laser power, layer thickness, and hatch spacing on roughness, density, and microhardness at constant input energy density
Authors: Greco Sebastian , Gutzeit Kevin , Hotz Hendrik , Kirsch Benjamin , Aurich Jan C.
Published: May 2020

In selective laser melting (SLM) the variation of process parameters significantly impacts the resulting workpiece characteristics. In this study, AISI 316L was manufactured by SLM with varying laser power, layer thickness, and hatch spacing. Contrary to most studies, the input energy density was kept constant for all variations by adjusting the scanning speed. The varied parameters were evaluated at two different input energy densities. The investigations reveal that a constant energy density with varying laser parameters results into considerable differences of the workpieces’ roughness, density, and microhardness. The density and the microhardness of the manufactured components can be improved by selecting appropriate parameters of the laser power, the layer thickness, and the hatch spacing. For this reason, the input energy density alone is no indicator for the resulting workpiece characteristics, but rather the ratio of scanning speed, layer thickness, or hatch spacing to laser power. Furthermore, it was found that the microhardness of an additively manufactured material correlates with its relative density. In the parameter study presented in this paper, relative densities of the additively manufactured workpieces of up to 99.9% were achieved.
Integrating Ecosystem Services in Nature Conservation for Colombia
Authors: Burgos-Ayala Aracely , Jiménez-Aceituno Amanda , Rozas-Vásquez Daniel
Published: May 2020

The ecosystem services (ES) approach has been introduced in environmental policies and management to serve as a link between nature and society. Communication, education, and participation actions (CEPA) have the potential to facilitate this link. In this research, we evaluated how CEPA have been implemented in biodiversity conservation projects that consider ES. We used content analysis to review 182 biodiversity conservation projects executed by 33 environmental authorities in Colombia. We also used multiple correspondence analysis and cluster analysis to classify projects on the basis of the purpose of CEPA, type of CEPA, integration of CEPA, ES addressed, main stakeholders, and aim of conservation. We found that five aspects are key to fostering social engagement in environmental management projects: promoting explicit consideration of the ES approaches, increasing conservation efforts focused on the non-material benefits of the ES, integrating different types of CEPA, including overlooked key actors (e.g., indigenous communities and women), and developing and implementing social indicators. These considerations might lead environmental managers to revise their daily practices and, eventually, inform policies that foster an explicit link between CEPA and ES approaches.
Habitat fragmentation and forest management alter woody plant communities in a Central European beech forest landscape
Authors: Bähner Kevin Wilhelm , Tabarelli Marcelo , Büdel Burkhard , Wirth Rainer
Published: May 2020

Habitat fragmentation and forest management have been considered to drastically alter the nature of forest ecosystems globally. However, much uncertainty remains regarding the causative mechanisms mediating temperate forest responses, such as forest physical environment and the structure of woody plant assemblages, regardless of the role these forests play for global sustainability. In this paper, we examine how both habitat fragmentation and timber exploitation via silvicultural operations affect these two factors at local and habitat spatial scales in a hyper-fragmented landscape of mixed beech forests spanning more than 1500 km2 in SW Germany. Variables were recorded across 57 1000 m2 plots covering four habitats: small forest fragments, forest edges within large control forests, as well as managed and unmanaged forest interior sites. As expected, forest habitats differed in disturbance level, physical conditions and community structure at plot and habitat scale. Briefly, diversity of plant assemblages differed across all forest habitats (highest in edge forests) and correlated with integrative indices of edge, fragmentation and management effects. Surprisingly, managed and unmanaged forests did not differ in terms of species richness at local spatial scale, but managed forests exhibited a clear signal of physical/floristic homogenization as species promoted by silviculture proliferated; i.e. impoverished communities at landscape scale. Moreover, functional composition of plant communities responded to the microclimatic regime within forest fragments, resulting in a higher prevalence of species adapted to these microclimatic conditions. Our results underscore the notion that forest fragmentation and silvicultural management (1) promote changes in microclimatic regimes, (2) alter the balance between light-demanding and shade-adapted species, (3) support diverse floras across forest edges, and (4) alter patterns of beta diversity. Hence, in human-modified landscapes edge-affected habitats can be recognized as biodiversity reservoirs in contrast to impoverished managed interior forests. Furthermore, our results ratify the role of unmanaged forests as a source of environmental variability, species turnover, and distinct woody plant communities.
Student Teachers’ and Experienced Teachers’ Professional Vision of Students’ Understanding of the Rational Number Concept
Authors: Pouta Maikki , Lehtinen Erno , Palonen Tuire
Published: May 2020

The aim of this study was to investigate differences in student teachers’ and experienced teachers’ professional vision in natural settings and to elicit clues of the relation of in-the-moment noticing and instruction quality of students’ understanding of rational number concept. Rational number concept challenges both students and teachers because of natural number bias that learning of rational numbers is vulnerable to. Accurate professional vision and adequate instructions are needed to enhance students’ understanding of rational number concept. Mobile eye-tracking technique enables video recording of natural teaching situations from a teacher’s perspective with more specific information of teacher’s in-the-moment noticing. Combined with cued retrospective reporting, this approach can gather more explicit evidence of teachers’ professional vision and instructions. Results indicated that both student teachers and experienced teachers attended to mathematical and fraction-related aspect similarly but differed in interpreting and instructing students’ fraction understanding. Student teachers made more advanced interpretations but their instructions were less adequate, whereas among experienced teachers, it was just the opposite. Furthermore, student teachers made more attempts to shared attention when using fraction understanding non-supporting instructions, whereas experienced teachers’ attempts to shared attention were related to fraction understanding supporting instructions. Results indicate student teachers’ difficulty to transfer pedagogical content knowledge from noticing to actions and experienced teachers to have more enhanced in-the-moment professional vision and its application to teaching. Practical implications for teacher training as well as methodological decisions of in-the-moment professional vision studies in natural settings are discussed.
Reliability-Based Stability Analysis of a Baltic Cliff by the Combined Response Surface Method
Authors: Winkelmann Karol , Zabuski Lesław , Przewłócki Jarosław , Górski Jarosław
Published: May 2020

The study presents a probabilistic stability analysis of a Baltic cliff in Jastrzębia Góra, Poland. Progressive slope erosion is a threat to adjacent buildings, so safety assessment of the slope is essential. The cliff shows a compound, multi-layered geological structure, which makes the analysis of its reliability a complex multivariate problem. A simple, straightforward computational procedure was proposed, incorporating the Response Surface Method (RSM) linked with the standard Monte Carlo (MC) simulation method and the Point Estimate Method (PEM). PEM samples make it possible to analyse the sensitivity of the cliff’s stability to variation in subsoil parameters and to reduce the number of random variables of the problem. The proposed methods were tested in two cases: a high failure probability (undrained state) and a moderate failure probability (drained case). The so-called combined Response Surface Method (CRSM) proposed here may be successfully applied in geotechnical computations characterized by dispersion and uncertainty of soil data as well as a relatively high damage probability.
Drift–diffusion simulation of S-shaped current–voltage relations for organic semiconductor devices
Authors: Doan Duy Hai , Fischer Axel , Fuhrmann Jürgen , Glitzky Annegret , Liero Matthias
Published: May 2020

We present an electrothermal drift–diffusion model for organic semiconductor devices with Gauss–Fermi statistics and positive temperature feedback for the charge carrier mobilities. We apply temperature-dependent Ohmic contact boundary conditions for the electrostatic potential and discretize the system by a finite volume based generalized Scharfetter–Gummel scheme. Using path-following techniques, we demonstrate that the model exhibits S-shaped current–voltage curves with regions of negative differential resistance, which were only recently observed experimentally.
Relationships Between Chemical Defenses of Common Toad (Bufo bufo) Tadpoles and Bacterial Community Structure of their Natural Aquatic Habitat
Authors: Ujszegi János , Vajna Balázs , Móricz Ágnes M. , Krüzselyi Dániel , Korponai Kristóf , Krett Gergely , Hettyey Attila
Published: May 2020

Many organisms synthesize secondary metabolites against natural enemies. However, to which environmental factors the production of these metabolites is adjusted to is poorly investigated in animals, especially so in vertebrates. Bufadienolides are steroidal compounds that are present in a wide range of plants and animals and, if present in large quantities, can provide protection against natural enemies, such as pathogens. In a correlative study involving 16 natural populations we investigated how variation in bufadienolide content of larval common toads (Bufo bufo) is associated with the bacterial community structure of their aquatic environment. We also evaluated pond size, macrovegetation cover, and the abundance of predators, conspecifics and other larval amphibians. We measured toxin content of tadpoles using HPLC-MS and determined the number of bufadienolide compounds (NBC) and the total quantity of bufadienolides (TBQ). AICc-based model selection revealed strong relationships of NBC and TBQ with bacterial community structure of the aquatic habitat as well as with the presence of conspecific tadpoles. The observed relationships may have arisen due to adaptation to local bacterial communities, phenotypic plasticity, differential biotransformation of toxin compounds by different bacterial communities, or a combination of these processes. Bacterial groups that contribute to among-population variation in toxin content remain to be pinpointed, but our study suggesting that toxin production may be influenced by the bacterial community of the environment represents an important step towards understanding the ecological and evolutionary processes leading to microbiota-mediated variation in skin toxin profiles of aquatic vertebrates.
The World Ends Here, the World Begins Here: Bronze Age Megalithic Monuments in Western Scotland
Authors: Higginbottom Gail
Published: May 2020

This paper presents a study of free-standing Bronze Age megalithic monuments across western Scotland: Argyll, Lochaber, Kintyre, and the isles of Mull, Coll and Tiree. The original project was designed to unearth the locational choices of their builders, the reasons for these choices, and what they reveal about the belief systems of these societies. Using statistical analyses and 2D and 3D GIS, it will be demonstrated that vision is the main force behind locational decisions. The GIS analyses revealed that the builders chose a particular horizon shape, defined by qualities of distance, direction and relative apparent height as viewed from the monument (altitude). Significantly, approximately half the sites have the same locational variables as all the sites considered on the isles of Coll and Tiree (labelled ‘classic sites’: Higginbottom et al. in J Archaeol Method Theory 22:584–645, 2015.10.1007/s10816-013-9182-7), while the other half are the topographical reverse (‘reverse sites’), where the major ‘astronomical show’ differs due to the topographical differences between the site types. It is relevant to note that landscapes that block views of particular major astronomical phenomena in the south are significantly more common at reverse sites than at classic sites. Specific results pertaining to individual areas will also be highlighted. It will be seen that the interplay between the astronomy and the topographical choices of the builders at each site highlights possible cosmological ideologies that can be observed and that were shared across western Scotland.
Content driving exposure and attention to tweets during local, high-impact weather events
Authors: Eachus Joshua D. , Keim Barry D.
Published: May 2020

The use of Twitter to disseminate weather information presents need for the analysis of what types of messages, and specifically warning messages, incur exposure and attention. Having this knowledge could increase exposure and attention to messages and perhaps increase retransmission through Twitter. Two models describe the cognitive processing of tweets and warnings. The extended parallel process model describes components of an effective warning message. Even in a tweet, ignoring one or both critical components of a warning—threat and efficacy—could inhibit a user from taking the correct protective action. The protective action decision model (PADM) describes risk perception and factors that enable or disable one from giving attention to a message. The PADM also helps to define impressions, retweets or likes as metrics of exposure or attention to a tweet. Tweets from three Twitter accounts within one television market during two high-impact weather events were examined. From an individual account, impressions, retweets and likes were collected to identify commonalities to tweets with much exposure and attention. Results indicate photographs and geographically specific messages were popular. Second, from two competing television weather accounts, warning tweet formats were compared to identify exposure and attention to each. Warning tweets providing threat and efficacy performed best. The purpose of this work is twofold. First is to identify local trends to compliment findings from studies with large sample sizes. Second is to apply existing theory on warning message content to Twitter. This approach should benefit communication strategies of key information nodes—local meteorologists—during high-impact weather events.