bluuebunny/crossref_metadata_2025 huggingface dataset:
A luminescent on–off probe based calix[4]arene linked through triazole with ruthenium(ii) polypyridine complexes to sense copper(ii) and sulfide ions
Authors: Ramachandran Mohanraj , Anandan Sambandam , Ashokkumar Muthupandian
Published: May 2019

The supramolecular sensor Ru2L was designed by joining a bis-ruthenium(ii) polypyridyl complex with a p-tert-butyl calix[4]arene platform through a 1,2,3-triazole linker and used for sensing of copper(ii) and sulfide ions by fluorescence.
Tuning the photochromic properties of chromophores containing a nitrile-rich acceptor: a novel branch in the investigation of negative photochromes
Authors: Belikov Mikhail Yu. , Ievlev Mikhail Yu. , Fedoseev Sergey V. , Ershov Oleg V.
Published: May 2019

High photoswitching contrast and variation of the thermal stability of the photoinduced form for a novel group of reverse photochromes are described for the first time.
Polymer-incarcerated palladium-catalyzed facile in situ carbonylation for the synthesis of aryl aldehydes and diaryl ketones using CO surrogates under ambient conditions
Authors: Dey Tusar Kanto , Basu Priyanka , Riyajuddin Sk , Ghosh Aniruddha , Ghosh Kaushik , Manirul Islam Sk
Published: May 2019

A palladium-incorporated heterogeneous catalyst, Pd@(Merf-FA), was designed for the synthesis of aryl aldehydes and diaryl ketones using carbonylative surrogates.
Highly active and durable Pd nanocatalyst promoted by an oxygen-deficient terbium oxide (Tb4O7−x) support for hydrogenation and cross-coupling reactions
Authors: Jiang Yi-Fan , Yuan Cheng-Zong , Cheang Tuck-Yun , Xu An-Wu
Published: May 2019

Oxygen-deficient Tb4O7−x as an effective promoter and support for Pd nanocatalysts holds great potential in hydrogenation and cross-coupling reactions.
Heterostructures of doped graphene and MoX2 (X = S and Se) as promising anchoring materials for lithium–sulfur batteries: a first-principles study
Authors: Zhang Tianqi , Wang Hongxia , Zhao Jingxiang
Published: May 2019

The heterostructures composed of a MoX2 (X = S or Se) nanosheet and doped graphene with B or N exhibit superior anchoring effects for soluble Li2Sn species.
One-pot synthesized Cu/Au/Pt trimetallic nanoparticles as a novel enzyme mimic for biosensing applications
Authors: Wu Pian , Ding Ping , Ye Xiaosheng , Li Lei , He Xiaoxiao , Wang Kemin
Published: May 2019

A class of novel Cu/Au/Pt TNPs with enhanced peroxidase-like activity was developed and used as enzyme mimics for biosensing.
Magnetic entropy table-like shape and enhancement of refrigerant capacity in La1.4Ca1.6Mn2O7–La1.3Eu0.1Ca1.6Mn2O7 composite
Authors: M'nassri R. , Nofal Muaffaq M. , de Rango P. , Chniba-Boudjada N.
Published: May 2019

In this work, we have investigated the structural, magnetic and magnetocaloric properties of La1.4Ca1.6Mn2O7 (A) and La1.3Eu0.1Ca1.6Mn2O7 (B) oxides.
Triazole-modified chitosan: a biomacromolecule as a new environmentally benign corrosion inhibitor for carbon steel in a hydrochloric acid solution
Authors: Chauhan Dheeraj Singh , Quraishi M. A. , Sorour A. A. , Saha Sourav Kr. , Banerjee Priyabrata
Published: May 2019

A novel derivative of chitosan is evaluated as an environment-friendly corrosion inhibitor for carbon steel in hydrochloric acid solution.
Improvement of perovskite crystallinity by omnidirectional heat transfer via radiative thermal annealing
Authors: Park Jiyoon , Choi Jin Woo , Kim Woochul , Lee Ryeri , Woo Hee Chul , Shin Jisoo , Kim Hyeonghun , Son Yeong Jun , Jo Ji Young , Lee Heon , Kwon Sooncheol , Lee Chang-Lyoul , Jung Gun Young
Published: May 2019

Perovskite solar cells produced by RTA demonstrate superior photovoltaic (PV) performances than those annealed on a hot plate.
Computational analysis of hot spots and binding mechanism in the PD-1/PD-L1 interaction
Authors: Huang Dading , Wen Wei , Liu Xiao , Li Yang , Zhang John Z. H.
Published: May 2019

The hot spots quantitatively predicted by the recently developed MM/GBSA/IE method reveal a hydrophobic core in the PD-1/PD-L1 interaction.
Effect of fatty acids and triglycerides on the formation of lysine-derived advanced glycation end-products in model systems exposed to frying temperature
Authors: Wang Yuting , Hu Huiyu , McClements David Julian , Nie Shaoping , Shen Mingyue , Li Chang , Huang Yousheng , Chen Jie , Zeng Maomao , Xie Mingyong
Published: May 2019

Fatty acids and triglycerides impact lysine-derived AGE formation through modulating the formation of α-dicarbonyl compounds and Amadori products.
Insulating 3D-printed templates are turned into metallic electrodes: application as electrodes for glycerol electrooxidation
Authors: Guima Katia-Emiko , Souza Victor H. R. , Martins Cauê Alves
Published: May 2019

Insulating printed plastics are turned into metallic pieces by electrochemical polymerization of aniline followed by metal electrodeposition.
Preparation, characterization, and use of novel Cu@Fe3O4 MNPs in the synthesis of tetrahydrobenzimidazo[2,1-b]quinazolin-1(2H)-ones and 2H-indazolo[2,1-b]phthalazine-triones under solvent-free conditions
Authors: Jiang Lilin , Druzhinin Zumrat
Published: May 2019

Cu@Fe3O4 MNPs as novel nanomagnetic reagents were prepared to investigate their catalytic behavior in the preparation of tetrahydrobenzimidazo[2,1-b]quinazolin-1(2H)-ones, as important biologically active compounds.
Optical and dielectric properties of NaCoPO4 in the three phases α, β and γ
Authors: Ajmi A. , Karoui K. , Khirouni K. , Ben Rhaiem A.
Published: May 2019

In this work, we are interested in the synthesis of monophosphate α-NaCoPO4, β-NaCoPO4 and γ-NaCoPO4 compounds by mechanochemical method and their characterization by X-ray powder diffraction patterns.
One-pot detection of telomerase activity with high sensitivity and specificity via RNA FRET probes and RNase H-assisted signal cycling amplification
Authors: Wang Honghong , Wang Hui , Jia Yuting , Zhang Mai , Li Zhengping
Published: May 2019

A one-pot method is developed for the detection of telomerase activity via RNA FRET probes and RNase H-assisted signal cycling amplification.
Interface depended electronic and magnetic properties of vertical CrI3/WSe2 heterostructures
Authors: Ge Mei , Su Yan , Wang Han , Yang Guohui , Zhang Junfeng
Published: May 2019

The out-plane easy axis is tuned into in-plane in both CrI3/WSe2 and WSe2/CrI3/WSe2 vertical heterostructures.
Estimating speciation of aqueous ammonia solutions of ammonium bicarbonate: application of least squares methods to infrared spectra
Authors: Milella Federico , Mazzotti Marco
Published: May 2019

The knowledge of the speciation and of the supersaturation of aqueous solutions of CO2 and NH3 is pivotal for the design and optimization of unit operations, e.g. absorption or crystallization, in the framework of ammonia-based CO2 capture systems.
Jet-mixing reactor for the production of monodisperse silver nanoparticles using a reduced amount of capping agent
Authors: Ranadive Pinaki , Parulkar Aamena , Brunelli Nicholas A.
Published: May 2019

The jet-mixing reactor can continuously produce monodisperse silver nanoparticles using limited amounts of capping agent.
Quaternized poly(arylene perfluoroalkylene)s (QPAFs) for alkaline fuel cells – a perspective
Authors: Miyake Junpei , Miyatake Kenji
Published: May 2019

The progress, potential and remaining challenges of state-of-the-art anion exchange membranes (AEMs), in particular, our quaternized poly(arylene perfluoroalkylene)s (QPAFs), for alkaline fuel cell applications, are overviewed and discussed.
Green synthesis of ultrathin edge-activated foam-like carbon nitride nanosheets for enhanced photocatalytic performance under visible light irradiation
Authors: Abdelhafeez Islam A. , Yao Qiufang , Wang Cixuan , Su Yiming , Zhou Xuefei , Zhang Yalei
Published: May 2019

Fabrication of few-layered polymeric carbon nitride (PCN) photocatalysts have attracted increasing attention owing to their substantial enhancement of the photocatalytic performance.
Improvement of piezoresistive sensing behavior of graphene sponge by polyaniline nanoarrays
Authors: Huang Jingxia , Wang Honggang , Li Zhangpeng , Wu Xianzhang , Wang Jinqing , Yang Shengrong
Published: May 2019

A novel rGPS composite with PANI nanoarrays decorated on the 3D ordered microstructure of rGO sponge exhibits high-accuracy detection for the artery wrist pulse of humans.
Vision‐based crater and rock detection using a cascade decision forest
Authors: Yan Yunfeng , Qi Donglian , Li Chaoyong
Published: May 2019

Both crater and rock detection are components of the autonomous landing and hazard avoidance technology (ALHAT) sensor suite, as craters and rocks represent the majority of landing hazards. Furthermore, places with scientific values are very probable next to craters and rocks. Unsupervised approaches, which potentially use the pattern recognition techniques of ring threshold finding, perform quickly; however, they suffer from handling small craters. The supervised pattern recognition method is more powerful but is time‐consuming. To address these issues, here, a simultaneous multi‐size crater and rock detection algorithm is studied. The authors propose a new supervised machine‐learning framework using a cascade decision forest. Sliding windows are utilised in order to search basic features, and a multi‐grained cascade structure is introduced to enhance the framework's ability to learn the representations of the features. The training time of the proposed algorithm on a PC is comparable to that of deep neural networks, and the efficiency is enhanced for a large‐scale database. The outputs of the simulation verify the effectiveness and validity of the introduced technique.
Statistical multidirectional line dark channel for single‐image dehazing
Authors: Salazar Colores Sebastián , Moya‐Sánchez Eduardo Ulises , Ramos‐Arreguín Juan‐Manuel , Cabal‐Yépez Eduardo
Published: May 2019

Outdoor scenes often contain atmospheric degradation, such as fog or haze, which deteriorate the performance of tracking, autonomous driving and surveillance systems, among others, making dehazing methods an area of considerable interest. However, some dehazing techniques are computationally demanding, generating a trade‐off between time‐consumption and restoration quality. A new method is proposed for improving outdoor images taken with haze effects while making them less time‐consuming. The proposed method was inspired by the Radon transform and tailored for dehazing images by computing the dark channel, in addition to using statistical computations and a heuristic approach to avoid saturated areas. The results obtained were subjected to a reduced‐reference image quality dehazing assessment, a full‐reference metrics Structural SIMilarity (SSIM) index and peak signal‐to‐noise ratio (PSNR) over real‐world and synthetic outdoor images. The results demonstrate that the proposed method presents an adequate balance between new visible edges, increased gradient and saturated pixels, in addition to obtaining at least a 5% increase in the SSIM index and, a 16% increase in the PSNR index, as well as being 5.37 times faster than the four dehazing methods recently introduced in the literature.
3D approach for fault identification within power transformers using frequency response analysis
Authors: Abu‐Siada Ahmed , Radwan Ibrahim , Abdou Ahmed F.
Published: May 2019

With the growing pool of aged power transformers, application of the sweep frequency response analysis (SFRA) to assess power transformers’ mechanical integrity has been given much attention. One of the research gaps in this field is the lack of reliable and automated techniques to interpret SFRA signatures. Conventional interpretation technique relies on visual inspection and personnel level of expertise, which may lead to inconsistent interpretation for the same signature. Furthermore, current SFRA technique fails in detecting transformer incipient mechanical deformations of low levels. To overcome these limitations, this paper presents a new three‐dimensional (3D)‐SFRA signature that comprises frequency, magnitude and phase angle in one plot. In contrary to the current interpretation practice that relies only on the magnitude plot, the proposed 3D signature exhibits more features, which can improve the SFRA identification accuracy. To automate and standardise the fault identification process, a digital image processing code is developed to extract some unique features from the proposed signature. The proposed technique is validated through finite element simulation analysis to detect short‐circuit turns, axial displacement and radial deformation of a three‐phase 40 MVA transformer and practical feasibility is assessed through its application to detect short‐circuit turns of a three‐phase 45 MVA transformer.
Postpartale plastisch-chirurgische Bauchwandrekonstruktion
bei Adipositas
Authors: Spindler Nick , Schreye-Peterson Susanne , Blüher Matthias , Stepan Holger , Langer Stefan
Published: May 2019

Einleitung Die Bauchwand bildet eine feste anatomische Einheit und ist
essentiell für die für Stabilisierung des Rumpfes. Erhöhter intraabdomineller
Druck und Veränderungen der Gravitationskräfte können zu Dysbalancen und
hierdurch Entwicklung von Rektusdiastasen und abdominellen Hernien führen.

Material/Methode Die Betreuung und operative Behandlung postpartaler
adipöser Patienten verlangt ein interdisziplinäres Konzept. In unserer Klinik
wurde hierzu ein spezieller Behandlungsalgorithmus für adipöse Patienten mit
postpartalen Bauchwandinsuffizienzen unter Berücksichtigung ihres BMI
erstellt.

Diskussion Der Verschluss von Rektusdiastasen ist eine zusätzliche Technik
bei durchgeführter Abdominoplastik. Hierdurch kann eine verbesserte
Stabilisierung der vorderen Bauchwand erzielt werden. Des Weiteren kann der
Operateur die Kontur der Taille wiederherstellen und das äußere Erscheinungsbild
optimieren. Je nach Ausmaß der Fettschürze und Größe der Hernien und Diastasen
stehen unterschiedliche chirurgische Behandlungsalternativen zur Verfügung.

Zusammenfassung Mit Hilfe der rekonstruktiven plastischen Chirurgie kann
bei diesem Patientengut eine funktionelle Rekonstruktion der Bauchwand
wiederhergestellt werden. Einen sekundären Therapiegewinn stellt die simultane
Mitbehandlung der ästhetischen Problemzonen dar und hilft eine langfristige
physische und psychosoziale Rehabilitation der Patientinnen zu ermöglichen.
Die Entwicklung von Figur- und Gewichtssorgen während und nach der Schwangerschaft: Der Einfluss von Übergewicht und Adipositas
Authors: Hanschmidt Franz , Nagl Michaela , Lehnig Franziska , Hoffmann Rahel , Zietlow Grit , Stepan Holger , Kersting Anette
Published: May 2019

Ziele Übergewicht und Adipositas in der Schwangerschaft sowie Figur- und Gewichtssorgen sind mit erhöhter physischer und psychischer Belastung assoziiert. Bisher ist allerdings wenig über die Entwicklung von Figur- und Gewichtssorgen bei schwangeren Frauen mit Übergewicht und Adipositas sowie Zusammenhänge mit der psychischen Gesundheit bekannt.

Methodik Die Studienteilnehmerinnen (N = 218) füllten validierte Fragebögen zu Figur- und Gewichtssorgen (Eating Disorder Examination-Questionnaire), Depression (Edinburgh Postnatal Depression Scale) und Stress (Perceived Stress Scale) in der 18.–22. Schwangerschaftswoche (SSW) (T1), der 28.–32. SSW (T2) und 12 bis 16 Wochen nach der Geburt (T3) aus. Der Einfluss von Body Mass Index (BMI) auf Figur- und Gewichtssorgen wurde mittels ANCOVAs mit Messwiederholungen untersucht. Korrelationen und multiple Regressionsmodelle wurden angewandt, um Zusammenhänge zwischen Figur- und Gewichtssorgen und der Depressions- und Stresssymptomatik zu explorieren.

Ergebnisse Frauen mit Übergewicht berichteten zwischen der 28.–32. SSW und der 12.–16. Woche nach der Geburt eine stärkere Zunahme von Figur- und Gewichtssorgen als normalgewichtige Frauen. In adjustieren Analysen sagten Figur- und Gewichtssorgen zu T1 über alle BMI-Kategorien hinweg Depressions- und Stresssymptome zu T3 vorher.

Schlussfolgerungen Die Ergebnisse dieser Studie zeigen, dass vor allem die Zeit nach der Entbindung eine Risikoperiode für die Entwicklung von Figur- und Gewichtssorgen bei Frauen mit erhöhtem BMI ist. Köperbildspezifische Interventionen vor und nach der Geburt könnten dazu beitragen, die psychische Belastung von Frauen mit Übergewicht und Adipositas zu verringern.
Clinical and endoscopic aspects of metastases to the gastrointestinal tract
Authors: Haendchen Bento Luiza , Kazuyoshi Minata Mauricio , Pires Batista Clelma , Martins Bruno da Costa , Lenz Tolentino Luciano Henrique , Scomparim Rodrigo Corsato , Shiguehissa Kawaguti Fábio , Gusmon de Oliveira Carla Cristina , Simas de Lima Marcelo , Naschold Geiger Sebastian , Ryoka Baba Elisa , Safatle-Ribeiro Adriana , Ribeiro Jr Ulysses , Maluf-Filho Fauze
Published: May 2019

Background Studies that describe metastases to the gastrointestinal (GI) tract are restricted to small case series. An increase in the frequency of this condition is expected, so it would be useful to better characterize the endoscopic aspects of metastasis to the GI tract. The aims of this study were to describe the frequency and endoscopic features of the lesions, and to analyze the survival rate after diagnosis of metastasis.

Methods This was a retrospective, single-center, observational study, conducted between 2009 and 2017. Patients with metastasis to the GI tract were included.

Results 95 patients were included. Melanoma (25.3 %), lung (15.8 %), and breast (14.7 %) were the most frequent primary tumors. The most common endoscopic presentation was a solitary, ulcerated lesion in the gastric body. Conventional biopsy was diagnostic in 98.9 % of the cases. The mean and median survival rates were 13.3 months (95 % confidence interval [CI] 8.2 – 18.3) and 4.7 months (95 %CI 3.7 – 5.6), respectively. Palliative treatment with chemo- and/or radiotherapy after the diagnosis of the metastasis was related to a higher survival rate.

Conclusions Melanoma, lung, and breast cancer were the most common primary tumors to metastasize to the GI tract. The endoscopic features could not predict the primary site of the tumor. The finding of metastasis in the GI tract is related to the final stage of the cancer disease but patients who received palliative treatment with chemo- and/or radiotherapy after diagnosis of GI metastasis had higher survival rates.
Chemo- and Regioselective Palladium(II)-Catalyzed Aminoaryl­ation of N-Allylureas Providing 4-Arylmethyl Imidazolidinones
Authors: Giofrè Sabrina , Beccalli Egle M. , Foschi Francesca , La Rosa Concetta , Lo Presti Leonardo , Christodoulou Michael S.
Published: May 2019

The aminoarylation reaction of N-allylureas under oxidative palladium catalysis, in the absence of ligands and by using inexpensive H2O2 as the sole oxidant, occurs in a chemo- and regioselective fashion. This intramolecular process takes place via a 5-exo-trig cyclization, and represents an easy approach to 4-arylmethyl imidazolidinones.
Timing of Free Flaps for Traumatic Wounds of the Lower Extremity: Have Advances in Perioperative Care Changed the Treatment Algorithm?
Authors: Patterson Charles W. , Stalder Mark W. , Richardson William , Steele Thomas , Wise M. Whitten , St Hilaire Hugo
Published: May 2019

Background Despite the landmark study by Godina 30 years ago, opinions still vary within the literature about the management of complex traumatic wounds in the lower extremity. We present a large series of lower extremity reconstructions with vascularized free tissue and examine the perioperative factors that influenced the success of these cases.

Methods We reviewed 88 patients with free flap reconstruction of traumatic lower extremity wounds over 8 years. Primary outcomes were flap infections, flap loss, total flap-specific complications, and total recipient site complications. Independent variables specific to perioperative care including time to flap coverage, injury classification, exposed or infected hardware, prior osteomyelitis, use of wound vacuum-assisted closure (VAC) therapy, and concurrent polytrauma were investigated to establish their influence on primary outcomes. Each independent variable was assessed using Chi-square or Fisher's exact test and was included in a logistic regression analysis to establish significance.

Results Of the 88 patients, 8 had flap loss, 8 had flap infections, and a total of 23 had primary adverse outcomes. Timing of the reconstruction, VAC use, injury classification, prior hardware or wound status, or presence of polytrauma had no statistically significant impact on the primary outcomes. Injury classification/severity on total recipient site complications (p = 0.051) and flap-specific complications (p = 0.073) trended toward significance; however, subgroup analysis did not achieve significance. Logistic regression of any recipient site complication including all independent variables similarly showed no significance.

Conclusion Although the original study by Godina suggests early coverage is critical to optimize outcomes, in the modern era of advanced wound care, our study adds to a growing body of evidence that supports the de-emphasis of the 72-hour reconstruction interval. Our current management is focused on more effectively coordinating efficient peritraumatic and perioperative care on an individualized basis in the often very complicated polytrauma patient.
Role of Oropharyngeal Administration of Colostrum in Very Low Birth Weight Infants for Reducing Necrotizing Enterocolitis: A Randomized Controlled Trial
Authors: Sharma Deepak , Kaur Amandeep , Farahbakhsh Nazanin , Agarwal Sunil
Published: May 2019

Objective This study aimed to study the role of oropharyngeal administration of colostrum (OAC) in very-low-birth-weight infants for reducing necrotizing enterocolitis (NEC).

Study Design In this randomized controlled trial, 117 infants were enrolled, 59 were randomized to OAC group and 58 to routine care group. Infants with birth weight ≤ 1,250 g and/or gestational age ≤ 30 weeks were enrolled. Infants in OAC group received maternal colostrum (0.2 mL), 0.1 mL on either side, after 24 hours of postnatal life and were given every 2 hour for the next 72 hours irrespective of the enteral feeding status of the neonate. The primary outcome of the study was the incidence of NEC (stage 2 or 3).

Results Baseline characteristics were comparable between the two groups. There was no significant reduction in the incidence of NEC in OAC group (0 [0%] vs. 3 [7.1%]; p = 0.11). There was significant reduction of 7 days of hospital stay in OAC group (34.2 ± 5.7 vs. 41.5 ± 6.7 days; p = 0.04).The incidence of early-onset sepsis, late-onset sepsis, blood culture positive sepsis, and ventilator-associated pneumonia were comparable between the two groups.

Conclusion OAC is safe and reduces the duration of hospital stay.
Does a Care Bundle Reduce Racial Disparities in Postcesarean Surgical Site Infections?
Authors: Kawakita Tetsuya , Umans Jason G.
Published: May 2019

Objective To examine the effect of a care bundle on racial disparities in surgical site infections (SSIs).

Study Design This was a retrospective cohort study of women undergoing cesarean delivery at ≥23 weeks' gestation. The care bundle included routine antibiotics (both cefazolin and azithromycin), chlorhexidine skin preparation, clippers, vaginal cleansing, placental removal by cord traction, subcutaneous tissue closure, suture skin closure, dressing removal in 24 to 48 hours, and postoperative chlorhexidine soap. Our primary outcome was SSI (superficial incisional, deep incisional, and organ/space) occurring up to 6 weeks. Adjusted odds ratios (aOR) with 95% confidence intervals (95% CI) were calculated, adjusting for predefined covariates.

Results Of 2,696 women, 1,947 were black (1,014 in the preimplementation period and 933 in the postimplementation period) and 749 were nonblack (370 in the preimplementation period and 379 in the postimplementation period). Regardless of race, women in the postimplementation period had lower rates of SSI compared with those in the preimplementation period (black: 2.9 vs. 5.2%, aOR: 0.53 [95% CI: 0.33–0.85]; nonblack: 1.1 vs. 3.5%, aOR: 0.28 [95% CI: 0.09–0.89]). There was no interaction by race (p for interaction = 0.94).

Conclusion The care bundle decreased SSI in both black and nonblack women but did not reduce racial disparities.
The role of the probe tip material in distinguishing p- and n-type domains in bulk heterojunction solar cells by atomic force microscopy based methods
Authors: Kratzer M. , Dimitriev O. P. , Fedoryak A. N. , Osipyonok N. M. , Balaz P. , Balaz M. , Tesinsky M. , Teichert C.
Published: May 2019

Visualization of functionally different domains in bulk heterojunction (BHJ) solar cells is of paramount importance to understand the routes of optimization of their structure for best performance. In this work, a concept of detecting n-type and p-type semiconductor domains in BHJ structures by methods based on atomic force microscopy (AFM) is proposed. It assigns an active role to the semiconducting coating of the AFM probe tip which is able to form different junctions, i.e., p-n anisotype or p+-p, n+-n isotype, with the surfaces inspected. Here, we illustrate this concept on the example of BHJ structures composed of the n-type inorganic microcrystalline semiconductor CdS and mechanochemically prepared p-type kesterite nanopowder and two types of AFM probe tip coatings, i.e., p-type boron-doped diamond and n-type nitrogen-doped diamond coating, respectively. Conductive AFM (CAFM) measurements demonstrated unequivocally the different diode behavior when contacting n- or p-type semiconductor domains in the BHJ structures. Simulation of the energy level alignment at the probe-sample interfaces allowed us to explain the formation of anisotype or isotype junctions depending on the sample domain and probe used. Kelvin probe force microscopy measurements were consistent with the CAFM results and indicated the different contact potentials from the diverse types of domains in the BHJ structure.
Visualizing Dirac nodal-line band structure of topological semimetal ZrGeSe by ARPES
Authors: Cheng Zhengwang , Zhang Zongyuan , Sun Haigen , Li Shaojian , Yuan Hui , Wang Zhijun , Cao Yan , Shao Zhibin , Bian Qi , Zhang Xin , Li Fangsen , Feng Jiagui , Ding Sunan , Mao Zhiqiang , Pan Minghu
Published: May 2019

As a member of ZrHM (H = Si/Ge/Sn; M = O/S/Se/Te) family materials, which were predicted to be the candidates of topological Dirac nodal-line semimetals, ZrGeSe exhibited particular properties, such as magnetic breakdown effect in the transport measurement, different from its other isostructural compounds, informing an unique topology of the electronic band structure. However, the related experimental research is insufficient until now. Here, we present a systematic study of the band structure and Fermi surfaces (FS) of ZrGeSe by angle-resolved photoemission spectroscopy (ARPES). Our Brillouin zone (BZ) mapping shows multiple Fermi pockets such as the diamond-shaped FS around the zone center Γ point, small electron pocket encircling the X point of the BZ, and lenses-shaped FS in the Γ-M direction. The obtained Fermi velocities and effective masses were up to 9.2 eV·Å and 0.42 me, and revealing an anisotropic electronic property along different high-symmetry k-space directions. Moreover, a kink appears near the Fermi level in the linear Dirac bands along the M-X direction, probably originated from the band hybridization and has not been reported in other ZrHM-type materials. Our findings support that the ZrHM-type material family can be a new platform on which to explore exotic states of quantum matter.
Generation of fractals as Duffing equation orbits
Authors: Akhmet Marat , Fen Mehmet Onur , Alejaily Ejaily Milad
Published: May 2019

Dynamics are constructed for fractals utilizing the motion associated with Duffing equation. Using the paradigm of Fatou-Julia iteration, we develop iterations to map fractals accompanied with a criterion to ensure that the image is again a fractal. Because of the close link between mappings, differential equations and dynamical systems, one can introduce dynamics for fractals through differential equations such that they become points of the solution trajectory. There is no doubt that the differential equations have a distinct role for studying chaos. Therefore, characterization of fractals as trajectory points is an important step toward a better understanding of the link between chaos and fractal geometry. Moreover, it would be helpful to enhance and widen the scope of their applications in physics and engineering.
Air-like plasma frequency in one-dimensional plasma photonic crystals
Authors: Tan Haiyun , Jin Chenggang , Zhuge Lanjian , Wu Xuemei
Published: May 2019

A one-dimensional plasma photonic crystal, which consists of periodically alternating layers of quartz discharge tubes and air, is proved to have a special photonic bandgap. It is found that in the absence of plasma, the quartz tube array can give rise to a bandgap within a fixed frequency band. Interestingly, both effective medium theory and experimental results reveal that such a bandgap can be closed in the existence of the plasma with an appropriate plasma density and can be reopened as the increase in the plasma density. The unique behavior of the bandgap also depends on the collision frequency of the plasma. To describe these phenomena, an air-like plasma frequency is defined. These studies pave the way for realizing tunable bandgaps in microwave applications.
Quantum Zeno effect generalized
Authors: Möbus Tim , Wolf Michael M.
Published: May 2019

The quantum Zeno effect, in its original form, uses frequent projective measurements to freeze the evolution of a quantum system that is initially governed by a fixed Hamiltonian. We generalize this effect simultaneously in three directions by allowing open system dynamics, time-dependent evolution equations, and general quantum operations in place of projective measurements. More precisely, we study Markovian master equations with bounded generators whose time dependence is Lipschitz continuous. Under a spectral gap condition on the quantum operation, we show how frequent measurements again freeze the evolution outside an invariant subspace. Inside this space, the evolution is described by a modified master equation.
Strain controlling transport properties of heterostructure composed of monolayer CrI3
Authors: Yang Baishun , Zhang Xiaolin , Yang Hongxin , Han Xiufeng , Yan Yu
Published: May 2019

The modulation of the magnetic state and spin orientation in two-dimensional (2D) intrinsic magnets is important for controlling the spin-dependent transport properties of 2D magnet-based heterostructures. In this work, using first-principles calculations, it is found that the Néel antiferromagnetic (AFM) state with in-plane spin and the ferromagnetic (FM) state with in-plane and out-of-plane spin can be achieved in monolayer CrI3 under appropriate in-plane strains. In particular, the conductance of the Graphite/monolayer-CrI3/Graphite van der Waals heterostructure increases with the increase in the tensile strain, and the rate of change in conductance reaches more than 1800% when the strain becomes larger than 20%, which is significantly larger than that of the van der Waals heterostructure with a nonmagnetic insulator as a barrier to the magnetic field. Interestingly, when the magnetic state in monolayer CrI3 is switched from the Néel AFM to FM state by strain, the anisotropy magnetoresistance (AMR) ratio of the Graphite/monolayer-CrI3/Graphite heterostructure changes from −34.8% to 70%. The changes of AMR and conductance with strain originate mainly from the variation of the bandgap of monolayer CrI3 and the average transmission channels of graphite. These findings enrich the method in tuning spin orientation and provide the route for controlling transport properties of the heterostructure by strain tuning spin orientation in 2D magnets.
Delta shock wave as self-similar viscosity limit for a strictly hyperbolic system of conservation laws
Authors: Sen Anupam , Raja Sekhar T.
Published: May 2019

In this article, we study the Riemann problem for a strictly hyperbolic system of conservation laws. The governing system arises in nonlinear elasticity and gas dynamics. The system is one of the examples of a strictly hyperbolic system whose Riemann solution consists of delta shock waves as well as classical elementary waves such as shock waves, rarefaction waves, and contact discontinuities. We discuss the existence and uniqueness of the solution of the Riemann problem involving δ-shock wave by using a self-similar vanishing viscosity approach. We show that δ-shock wave is a weak*-limit of L1 solution to some viscous perturbations as the viscosity vanishes.
Principal component analysis of the excluded area of two-dimensional hard particles
Authors: Geigenfeind Thomas , de las Heras Daniel
Published: May 2019

The excluded area between a pair of two-dimensional hard particles with given relative orientation is the region in which one particle cannot be located due to the presence of the other particle. The magnitude of the excluded area as a function of the relative particle orientation plays a major role in the determination of the bulk phase behavior of hard particles. We use principal component analysis (PCA) to identify the different types of excluded areas corresponding to randomly generated two-dimensional hard particles modeled as non-self-intersecting polygons and star lines (line segments radiating from a common origin). Only three principal components are required to have an excellent representation of the value of the excluded area as a function of the relative particle orientation for sufficiently anisotropic particles. Independent of the particle shape, the minimum value of the excluded area is always achieved when the particles are antiparallel to each other. The property that affects the value of the excluded area most strongly is the elongation of the particle shape. PCA identifies four limiting cases of excluded areas with one to four global minima at equispaced relative orientations. We study selected particle shapes using Monte Carlo simulations.
Efficient calculation of X-ray absorption spectra using Chebyshev-Slepian filter diagonalisation
Authors: Neville Simon P. , Schuurman Michael S.
Published: May 2019

The efficient, yet accurate, simulation of X-ray absorption spectra represents a significant challenge for ab initio electronic structure methods. Conventional approaches involve the explicit calculation of all core-excited states spanning the energy range of interest, even though only a small number of these states will contribute appreciably to the spectrum. We here report a different approach, based on a time-independent Chebyshev filter diagonalization scheme, which allows for the X-ray absorption spectrum to be computed without the explicit calculation of the core-excited eigenstates. Furthermore, in a subsequent postprocessing calculation, selected peaks may be analyzed via the calculation of natural transition orbitals, if desired. The scheme presented here is based on a refinement of the time-independent Chebyshev filter diagonalization approach. Previous formulations of this method have been characterized by a requirement for significant “user input” via the (sometimes unintuitive) tuning of various numerical parameters. To circumvent this, we introduce a new class of filters based on discrete prolate spheroidal sequences. We demonstrate that the resulting method, which we term Chebyshev-Slepian filter diagonalization, makes filter diagonalization essentially a black-box procedure. The Chebyshev-Slepian filter diagonalization method is implemented at the second-order algebraic diagrammatic construction level of theory and validated through the calculation of the X-ray absorption spectra of trifluoroacetonitrile and 1,4-benzoquinone.
Electrical double layer in molten salts with account of soft repulsions
Authors: Kłos Jacek , Lamperski Stanisław
Published: May 2019

Results of Monte Carlo simulations of the electrode-molten salt interface are reported. The system was modeled by soft ions in contact with a soft wall using the Lennard-Jones potential restricted to the repulsion part. The soft wall was formed of C (graphite), Hg, and Pb atoms. Calculations were carried out for the parameter values which would permit making comparison with the real system. The paper presents information on physicochemical properties of the interfacial region, such as the ion singlet distribution functions, the mean electrostatic potential as a function of the distance from the electrode surface, and differential capacitance results as a function of the electrode charges. The differential capacitance curves have a flat and distorted bell shape which vary depending on the kind of the electrode material. The differential capacitance results are discussed and compared with the data obtained from ionic liquid simulations, density functional theory, and mean field calculations.
Unraveling the metastability of the SI and SII carbon monoxide hydrate with a combined DFT-neutron diffraction investigation
Authors: Pétuya Claire , Martin-Gondre Ludovic , Aurel Philippe , Damay Françoise , Desmedt Arnaud
Published: May 2019

Clathrate hydrates are crystalline compounds consisting of water molecules forming cages (so-called “host”) inside of which “guest” molecules are encapsulated depending on the thermodynamic conditions of formation (systems stable at low temperature and high pressure). These icelike systems are naturally abundant on Earth and are generally expected to exist on icy celestial bodies. Carbon monoxide hydrate might be considered an important component of the carbon cycle in the solar system since CO gas is one of the predominant forms of carbon. Intriguing fundamental properties have also been reported: the CO hydrate initially forms in the sI structure (kinetically favored) and transforms into the sII structure (thermodynamically stable). Understanding and predicting the gas hydrate structural stability then become essential. The aim of this work is, thereby, to study the structural and energetic properties of the CO hydrate using density functional theory (DFT) calculations together with neutron diffraction measurements. In addition to the comparison of DFT-derived structural properties with those from experimental neutron diffraction, the originality of this work lies in the DFT-derived energy calculations performed on a complete unit cell (sI and sII) and not only by considering guest molecules confined in an isolated water cage (as usually performed for extracting the binding energies). Interestingly, an excellent agreement (within less than 1% error) is found between the measured and DFT-derived unit cell parameters by considering the Perdew-Burke-Ernzerhof (denoted PBE) functional. Moreover, a strategy is proposed for evaluating the hydrate structural stability on the basis of potential energy analysis of the total nonbonding energies (i.e., binding energy and water substructure nonbonding energy). It is found that the sII structure is the thermodynamically stable hydrate phase. In addition, increasing the CO content in the large cages has a stabilizing effect on the sII structure, while it destabilizes the sI structure. Such findings are in agreement with the recent experimental results evidencing the structural metastability of the CO hydrate.
Chemical mist deposition of organic for efficient front- and back-PEDOT:PSS/crystalline Si heterojunction solar cells
Authors: Islam A.T.M. Saiful , Karim Md. Enamul , Rajib Arifuzzaman , Nasuno Yuki , Ukai Tomofumi , Kurosu Shunji , Tokuda Masahide , Fujii Yasuhiko , Nakajima Yoshikata , Hanajiri Tatsuro , Shirai Hajime
Published: May 2019

We have investigated an n-type crystalline Si (n-Si) heterojunction solar cell with organic conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) on a plane and isotropically textured n-Si substrate by using chemical mist deposition (CMD). The PEDOT:PSS layer was deposited uniformly on isotropically textured n-Si with the increased passivation of surface defects of n-Si and stronger adhesion rather than the spin-coated film by adjusting deposition parameters. The power conversion efficiency increased from 12.5% on plane n-Si to 16%–18.2% for both CMD coated front- and back-PEDOT:PSS/n-Si junction solar cells on the 2 × 2 cm2-sized isotropically textured substrate by combining with a 1–2-nm-thick Ba(OH)2 by CMD as a hole-blocking layer at the Al/n-Si interface. These findings originate from the increased passivation of surface dangling bonds of isotropically textured n-Si, resulting in strong inversion of the n-Si surface to p-type Si by the polymer.
Real-time observation of fast and highly reliable magnetization switching in Voltage-Control Spintronics Memory (VoCSM)
Authors: Inokuchi T. , Yoda H. , Koi K. , Shimomura N. , Ohsawa Y. , Kato Y. , Shirotori S. , Shimizu M. , Sugiyama H. , Oikawa S. , Altansargai B. , Kurobe A.
Published: May 2019

Magnetization switching was observed in real time in voltage-control spintronics memory (VoCSM), which utilizes a hybrid writing method that combines spin–orbit torque and voltage-controlled magnetic anisotropy (VCMA). VCMA lowers the switching energy barrier between parallel and antiparallel states, leading to a reduction in the write current and acceleration of magnetization switching. Real-time observation revealed that this acceleration of magnetization switching was accomplished by reducing the incubation and switching times. Using this writing method, high write durability was realized over 1013 write cycles using 2-ns write pulses. These results indicate that VoCSM realizes high speed and highly reliable switching with low power consumption and has the potential to shape next-generation computing systems.
Using naturally occurring climate resilient corals to construct bleaching-resistant nurseries
Authors: Morikawa Megan K. , Palumbi Stephen R.
Published: May 2019

Ecological restoration of forests, meadows, reefs, or other foundational ecosystems during climate change depends on the discovery and use of individuals able to withstand future conditions. For coral reefs, climate-tolerant corals might not remain tolerant in different environments because of widespread environmental adjustment of coral physiology and symbionts. Here, we test if parent corals retain their heat tolerance in nursery settings, if simple proxies predict successful colonies, and if heat-tolerant corals suffer lower growth or survival in normal settings. Before the 2015 natural bleaching event in American Samoa, we set out 800 coral fragments from 80 colonies of four species selected by prior tests to have a range of intraspecific natural heat tolerance. After the event, nursery stock from heat-tolerant parents showed two to three times less bleaching across species than nursery stock from less tolerant parents. They also retained higher individual genetic diversity through the bleaching event than did less heat-tolerant corals. The three best proxies for thermal tolerance were response to experimental heat stress, location on the reef, and thermal microclimate. Molecular biomarkers were also predictive but were highly species specific. Colony genotype and symbiont genus played a similarly strong role in predicting bleaching. Combined, our results show that selecting for host and symbiont resilience produced a multispecies coral nursery that withstood multiple bleaching events, that proxies for thermal tolerance in restoration can work across species and be inexpensive, and that different coral clones within species reacted very differently to bleaching.
Bone resorption and body reorganization during maturation induce maternal transfer of toxic metals in anguillid eels
Authors: Freese Marko , Rizzo Larissa Yokota , Pohlmann Jan-Dag , Marohn Lasse , Witten Paul Eckhard , Gremse Felix , Rütten Stephan , Güvener Nihan , Michael Sabrina , Wysujack Klaus , Lammers Twan , Kiessling Fabian , Hollert Henner , Hanel Reinhold , Brinkmann Markus
Published: May 2019

Significance

Body reorganization in eels during gametogenesis can induce undesired side effects with possible pathological significance. This study provides analytical evidence for the maternal transfer of toxic metals from soft and hard tissues to the ovaries of mature females. By illustrating the metabolic fluxes and fate of mobilized minerals and metals in the fishes’ bodies during sexual development, we have identified a previously unreported aspect of anthropogenic impact on endangered anguillid eels. Furthermore, our findings suggest a physiologically connected interplay of energy metabolism and bone resorption in the reproductive strategy of eels. Consequently, we propose the eel as an interesting model organism for investigating the physiological pathways connecting lipid metabolism and mineral retention, known also to affect the health state of humans.
Dated language phylogenies shed light on the ancestry of Sino-Tibetan
Authors: Sagart Laurent , Jacques Guillaume , Lai Yunfan , Ryder Robin J. , Thouzeau Valentin , Greenhill Simon J. , List Johann-Mattis
Published: May 2019

Significance

Given its size and geographical extension, Sino-Tibetan is of the highest importance for understanding the prehistory of East Asia, and of neighboring language families. Based on a dataset of 50 Sino-Tibetan languages, we infer phylogenies that date the origin of the language family to around 7200 B.P., linking the origin of the language family with the late Cishan and the early Yangshao cultures.
Distinct differences in the nanoscale behaviors of the twist–bend liquid crystal phase of a flexible linear trimer and homologous dimer
Authors: Tuchband Michael R. , Paterson Daniel A. , Salamończyk Mirosław , Norman Victoria A. , Scarbrough Alyssa N. , Forsyth Ewan , Garcia Edgardo , Wang Cheng , Storey John M. D. , Walba David M. , Sprunt Samuel , Jákli Antal , Zhu Chenhui , Imrie Corrie T. , Clark Noel A.
Published: May 2019

Significance

The twist–bend (TB) liquid crystal phase is the newest nematic phase, having only been identified in 2011. Still, there are many outstanding mysteries about the nature of its nanoscale organization and behavior. We elucidate how the number of monomer units in a linear TB oligomer influences the structure of its nanoscale helix, an important TB phase structure–property relationship. While a TB dimer exhibits a temperature-dependent variation of its helix pitch, the analogous trimer features a temperature-independent helix pitch considerably shorter than that of the dimer and other known TB materials. This study illuminates the scope of possible variations that manifest in the TB phase and represents a substantial step in controlling its nanoscale behavior for technological applications.