bluuebunny/crossref_metadata_2025 huggingface dataset:
Phenolic profile and antioxidant activity of different grape (Vitis viniferaL.) varieties
Authors: Di Lorenzo C. , Colombo F. , Biella S. , Orgiu F. , Frigerio G. , Regazzoni L. , de Sousa L.P. , Bavaresco L. , Bosso A. , Aldini G. , Restani P.
Published: February 2019

In the last years, the interest in non-alcoholic grape products has considerably increased. Table grapes are largely produced in the Mediterranean area and their consumption has raised worldwide. Beside the positive pattern of nutrients, table grapes could provide benefits on human health. Among the health-promoting substances contained in table grapes, flavonoids (mainly anthocyanins, flavan-3-ols and flavonols) seem to be the most interesting. The aim of this study was the characterization of the phenolic pattern of sixteen grape varieties, and the evaluation of the associated antioxidant activity. The methods were: 1) Folin-Cocalteau's assay for the quantification of total polyphenol content; 2) DPPH (1,1,-diphenil-2—picrylhydrazyl) assay and 3) ORAC (Oxygen Radical Absorbance Capacity) spectrophotometric assays for the assessment of radical scavenging activity; 4) High Performance Liquid Chromatography (HPLC) method, coupled with electrospray ionization mass spectrometer (ESI-MS) and DAD detector was developed in order to obtain the phenolic pattern of grape samples. Data obtained in this study underline that some table grape varieties can show interesting phenolic pattern independently from the presence or not of seeds. This observation suggests that selected varieties of seedless grapes could represent an interesting source of healthy compounds, satisfying consumers' preferences and reducing concerns versus alcoholic beverages.
Analysis of allergenic residues in wines by triple quadrupole LCMS
Authors: Spinelli F.R. , Cargnel G.J. , Drehmer A.P. , Blatt C. , Baptistão M. , Vanderlinde R.
Published: February 2019

During the winemaking are used technology coadjuvants, between them: albumin, caseinates and lysozyme. These compounds have great oenological properties, however, the presence of their residues can represent risks to people who are allergic to them because they are derived from eggs and milk. Mass spectrometry methods enables unambiguous determination of allergenic proteins at low levels in wines. Therefore, the aim of this study was to determine the concentrations of ovalbumin, alpha-casein, beta-casein and lysozyme in experimental wines treated with different concentrations of them by triple quadrupole liquid chromatography mass spectrometry with Jet Stream Electrospray Ionization (ESI). The wines were elaborated and treated with different concentrations of albumin, lysozyme and potassium caseinate. Bentonite and decantation were used for the removal of the fining agents. The quantification limits (LOQ) for ovalbumin, a-casein, b-casein and lysozyme were: 0.002 mg/L, 0.24 mg/L, 0.75 mg/L and 0.04 mg/L, respectively. Non residues of the proteins were identified in the experimental wines treated with the different amounts of potassium caseinate, albumin and lysozyme, analyzed in this study. These results provide an evidence of the absence of residues of caseinate, albumin and lysozyme in the concentrations tested in the wines if good treatment practices are followed.
Beurteilung von moderatem Weinkonsum und Alkoholmissbrauch aus Sicht deutscher und ungarischer Konsumenten
Authors: Szolnoki G. , Stein-Hammer C. , Brazsil D.
Published: February 2019

Die Differenzierung zwischen moderatem Konsum alkoholischer Getränke und Alkoholmissbrauch wird in der Medizin, Soziologie und Politik zunehmend kontrovers diskutiert. Trotz sich zum Teil widersprechender Studienergebnisse, steht aktuell die Forderung im Raum nach generell niedrigeren Richtwerten für Alkohol, als in vielen Ländern festgelegt. Allerdings reicht die Spannbreite der weltweiten Guidelines von 10 bis 40 Gramm Alkohol/Tag. Für Deutschland werden je nach Absender 12 bzw. 14 Gramm täglich für Frauen und das Doppelte für Männer als moderat definiert, in Ungarn 17 Gramm (Frauen) und 34 Gramm (Männer). Dies wirft die Frage auf, wie Konsumenten den Zusammenhang zwischen Gesundheit, Weinkonsum und Alkoholmissbrauch einschätzen. Um auch kulturelle Unterschiede analysieren zu können, wurde 2017/18 eine repräsentative Befragung sowohl in Deutschland als auch in Ungarn mit 2000 bzw. 1500 Befragten durchgeführt. Die Befragungen beinhalteten Themen wie die Beurteilung und Definition des Alkoholmissbrauchs und moderaten Weinkonsums. Die Ergebnisse zeigen, dass in Ungarn der “moderate Weinkonsum” anders definiert wird als in Deutschland. Während die Deutschen die moderate Weinmenge durchschnittlich mit 0.31 l Wein/Tag definieren, liegt der gleiche Wert in Ungarn bei 0.36 l. Auch im Fall des Alkoholmissbrauchs ergaben sich Unterschiede: Deutschland gibt dafür 0.76 l Wein/Tag und Ungarn 1 l Wein/Tag an. Jedoch lassen sich auch Ähnlichkeiten, vor allem in der generellen Einschätzung von Alkoholmissbrauch erkennen. Unabhängig vom kulturellen Hintergrund waren die Befragten einig, dass übermäßiger Weinkonsum der Gesundheit schadet und dass sich nur leichter bis moderater Weinkonsum mit gesundem Lebensstil vereinbaren lässt.
Neutronic benchmark of the molten salt fast reactor in the frame of the EVOL and MARS collaborative projects
Authors: Brovchenko Mariya , Kloosterman Jan-Leen , Luzzi Lelio , Merle Elsa , Heuer Daniel , Laureau Axel , Feynberg Olga , Ignatiev Victor , Aufiero Manuele , Cammi Antonio , Fiorina Carlo , Alcaro Fabio , Dulla Sandra , Ravetto Piero , Frima Lodewijk , Lathouwers Danny , Merk Bruno
Published: February 2019

This paper describes the neutronic benchmarks and the results obtained by the various participants of the FP7 project EVOL and the ROSATOM project MARS. The aim of the benchmarks was two-fold: first to verify and validate each of the code packages of the project partners, adapted for liquid-fueled reactors, and second to check the dependence of the core characteristics to nuclear data set for application on a molten salt fast reactor (MSFR). The MSFR operates with the thorium fuel cycle and can be started with 233U-enriched U and/or TRU elements as initial fissile load. All three compositions were covered by the present benchmark. The calculations have confirmed that the MSFR has very favorable characteristics not present in other Gen4 fast reactors, like strong negative temperature and void reactivity coefficients, a low-fissile inventory, a reduced long-lived waste production and its burning capacities of nuclear waste produced in currently operational reactors.
Development of ground pipeline system for high-level scientific data products of the Hisaki satellite mission and its application to planetary space weather
Authors: Kimura Tomoki , Yamazaki Atsushi , Yoshioka Kazuo , Murakami Go , Tsuchiya Fuminori , Kita Hajime , Tao Chihiro , Yoshikawa Ichiro , Kumamoto Atsushi , Yamauchi Chisato
Published: February 2019

The Hisaki satellite is the first-ever space telescope mission dedicated to planetary sciences. Atmospheres and magnetospheres of our solar system planets are continuously monitored by the extreme ultraviolet (EUV) spectrometer onboard Hisaki. This paper describes a data pipeline system developed for processing high-level scientific and ancillary data products from the Hisaki mission. The telemetry data downlinked from the satellite are stored in a ground telemetry database, processed in the pipeline to imaging spectral data with a 1-min temporal resolution and ancillary data products, and then archived in a public database. The imaging spectra can be further reduced to higher-level data products for practical scientific use. For example, light curves of the power emitted from Jupiter’s aurora and plasma torus with a temporal resolution of 10-min can be reduced from the imaging spectral data; the reduced light curves reveal the transport processes of energy and mass in Jupiter’s magnetosphere and associated interplanetary solar wind conditions. Continuous monitoring with Hisaki will contribute considerably to our understanding of space weather relating to planets in our solar system.
Kariesexkavation – der aktuelle Stand
Authors: Göstemeyer Gerd , Schwendicke Falk
Published: February 2019

Ein verändertes Verständnis zur Ätiologie der Erkrankung „Karies“ spiegelt sich auch in einer drastisch veränderten Therapie kariöser Läsionen wider. So werden Strategien zur Kariesexkavation, bei denen eine vollständige Entfernung kariösen Gewebes angestrebt wird, heute teilweise hinterfragt. Moderne Vorgehensweisen zielen auf eine minimalinvasive Kariesentfernung ab mit anschließender Versiegelung der Kavität.
Synthesis of 2-Pyrrolidinones by Palladium-Catalyzed [3+2] Cycloaddition of Isocyanates
Authors: Breinbauer Rolf , Kljajic Marko , Schlatzer Thomas
Published: February 2019

Pd/DPEphos catalyzes the [3+2] cycloaddition of various alkyl isocyanates with 2-acetoxymethyl-3-allyltrimethylsilane as a synthetic equivalent of trimethylenemethane (TMM). Taking advantage of 2-acetoxymethyl-3-allyltrimethylsilane acting both as nucleophile as well as electrophile this reaction gives a convenient access to 5-ring lactams with an exocyclic alkene moiety. The formation of the β,γ-unsaturated 2-pyrrolidinones occurs without olefin isomerization and without epimerization of the stereogenic centers. Mechanistic investigations suggest an initial N-allylation of the isocyanate followed by nucleophilic ring closure furnishing the desired 2-pyrrolidinones.
Efficient Synthesis of 4,7-Dihydro-1H-oxepino[2,3-c]pyrazoles by Potassium Carbonate Promoted [4+3] Annulation of Crotonate-Derived Sulfur Ylides with Benzylidenepyrazolones
Authors: Wang Dian , Wang Xue , Zhang Xuange , Miao Zhiwei
Published: February 2019

The [4+3] annulation reaction of crotonate-derived sulfur ylides with benzylidenepyrazolones using K2CO3 as the base is reported. The ready availability of starting materials and the simple cyclization procedure make this approach suitable for the preparation of a diverse array of 4,7-dihydro-1H-oxepino[2,3-c]pyrazoles in good to excellent yields.
Base-Metal-Catalyzed Olefin Isomerization Reactions
Authors: Liu Qiang , Liu Xufang , Li Bin
Published: February 2019

The catalytic olefin isomerization reaction is a highly efficient and atom-economic transformation in organic synthesis that has attracted tremendous attention both in academia and industry. Recently, the development of Earth-abundant metal catalysts has received growing interest owing to their wide availability, sustainability, and ­environmentally benign nature, as well as the unique properties of non-precious metals. This review provides an overview of a broad range of base-metal-catalyzed olefin isomerization reactions categorized ­according to their different reaction mechanisms.

1 Introduction

2 Base-Metal-Catalyzed Olefin Isomerization Reactions

3 Base-Metal-Catalyzed Cycloisomerization Reactions

4 Conclusion
Chemoselective Intermolecular Cross-Benzoin Reaction of Aliphatic Aldehydes and Isatins via N-Heterocyclic Carbene Catalysis
Authors: Ji Haojie , Xu Jianfeng , Ren Hongjun
Published: February 2019

An N-heterocyclic carbene (NHC)-catalyzed chemoselective intermolecular cross-benzoin reaction of aliphatic aldehydes with isatins is developed, affording biologically important 3-substituted 3-hydroxyoxindoles (on gram scale) in moderate to good yields (46–90%). The employment of a morpholinone-derived pentafluorophenyl-substituted triazolium salt as the electron-deficient NHC pre-catalyst is essential to make the reaction go through the cross-benzoin reaction pathway rather than the hydroacylation reaction pathway.
Complete Covalent Structure of Human Platelet Factor 4
Authors: Morgan Francis J , Begg Geoffrey S , Chesterman Colin N
Published: February 2019

The amino acid sequence of the subunit of human platelet factor 4 has been determined. Human platelet factor 4 consists of identical subunits containing 70 amino acids, each with a molecular weight of 7,756. The molecule contains no methionine, phenylalanine or tryptophan. The proposed amino acid sequence of PF4 is: Glu-Ala-Glu-Glu-Asp-Gly-Asp-Leu-Gln-Cys-Leu-Cys-Val-Lys-Thr-Thr-Ser- Gln-Val-Arg-Pro-Arg-His-Ile-Thr-Ser-Leu-Glu-Val-Ile-Lys-Ala-Gly-Pro-His-Cys-Pro-Thr-Ala-Gin- Leu-Ile-Ala-Thr-Leu-Lys-Asn-Gly-Arg-Lys-Ile-Cys-Leu-Asp-Leu-Gln-Ala-Pro-Leu-Tyr-Lys-Lys- Ile-Ile-Lys-Lys-Leu-Leu-Glu-Ser. From consideration of the homology with p-thromboglobulin, disulphide bonds between residues 10 and 36 and between residues 12 and 52 can be inferred.
Plasmacytoid Urothelial Carcinoma of the Bladder: Case Report and Review of the Literature
Authors: Molina Barrera Ángela , Vásquez Franco Andrea , Aristizábal Andrés Felipe , Correa Galeano David , Cabrales Hessen Manuel
Published: February 2019

Introduction Plasmacytoid urothelial carcinoma (PUC) of the bladder is a rare histological variant, accounting for 1 to 3% of the invasive urothelial carcinomas, and it is typically aggressive. So far, it has not been well characterized, and the literature is based on reports and case series.

Case Report A 70-year-old male patient presenting with 4 months of constitutional and urinary symptoms, with an ultrasound finding of bilateral hydronephrosis and diffuse thickening of the bladder walls. In the cystoscopy, trigone of infiltrated appearance, a biopsy wass performed, whose immunohistochemistry revealed a PUC. The abdominopelvic image showed an infiltrative lesion that compromised the muscle of the bladder and extended to the perivesical fat, without adequate plane of cleavage with the prostate and a single hypogastric adenopathy suspected of malignancy. It was classified as cT3b vs cT4aN1M0 (chest computed tomography [CT] negative for malignancy), and the patient was submitted to a radical cystoprostatectomy, extended pelvic lymphadenectomy and non-continent urinary diversion with ileal conduit. The pathology revealed a diffuse PUC with prostatic stromal involvement and 22 of 39 lymph nodes positive for malignancy. Finally, the patient presented a series of postoperative complications and died.

Conclusion Plasmacytoid urothelial carcinoma of the bladder is a rare entity, characterized by high aggressiveness, an advanced stage at the time of diagnosis, and a poor prognosis. Currently, an aggressive approach is recommended due to its high invasive potential.
Weight-Based Guide Overestimates Endotracheal Tube Tip Position in Extremely Preterm Infants
Authors: Pereira Sujith S. , Raja Edwin-Amalraj , Satas Saulius
Published: February 2019

Objective To evaluate the association between endotracheal tube (ETT) tip position and adverse pulmonary outcomes using chest X-ray (CXR) in extremely preterm infants in whom ETT insertion length was estimated using weight + 6 guide (adding 6 cms to the infant’s weight in kg).

Study Design CXRs of 85 infants performed in the first week were reviewed for right-sided atelectasis, air leaks, and uneven lung inflation. The first CXR was later reviewed to document the ETT tip. Regression analysis was performed to find the association between ETT tip position and adverse outcome after adjusting for other confounders.

Results Forty (46%) infants had ETT tip placement between the first and second thoracic vertebrae (optimal position) compared with 45 (53%) who had the ETT tip placement outside this range (suboptimal position). Infants with suboptimal ETT were ventilated for a longer period (6.1 vs. 15.9 days; p = 0.004). The odds of adverse outcomes was 11.6 (95% confidence interval: 3.03, 44.1) times higher among infants who did not have ETT at the optimal position compared with infants who had ETT at the optimal position.

Conclusion Weight + 6 guide is not recommended to estimate ETT insertion length in extremely preterm infants. Gestation-based guide may be more appropriate to estimate ETT insertion length in this group of infants.
Lower Extremity Blood Flow Velocity in Obese versus Nonobese Pregnant Women
Authors: Dutta Eryn H. , Burns Ralph N. , Pacheco Luis D. , Marrs Caroline C. , Koutrouvelis Aristides , Koutrouvelis Gayle L. Olson
Published: February 2019

Objective Obesity and pregnancy are risk factors for venous thromboembolism (VTE). In nonpregnant individuals, abdominal obesity is associated with venous insufficiency. This study aimed to compare venous Doppler volume flow and velocity in the lower extremities of obese versus nonobese women.

Study Design A prospective cohort study was performed. Duplex ultrasound examined bilateral lower extremity venous flow and velocity (time-averaged mean velocity, TAMV). Flow was analyzed at the superficial femoral (SFV), distal external iliac (DEI), common femoral, profunda femoris, and popliteal veins. Mann–Whitney U-test, Spearman's correlation, and chi-square tests were used, with a significance of p < 0.05.

Results Left SFV TAMV and volume flow were higher in the obese group (5.1 [4.1–5.7] vs. 2.8 [1.7–3.4] cm/second; p < 0.001) and (89 [73–119] vs. 48 [26–62] cm/minute; p = 0.005). Significant differences were noted for right DEI flow (obese 326 [221–833] vs. nonobese 182 [104–355] cm/minute; p = 0.049). The right femoral profunda flow was also higher in obese (49 [40–93] cm/minute) compared with nonobese (31 [22–52] cm/minute; p = 0.041).

Conclusion Volume flow and TAMV in the lower extremities of obese gravidas are higher compared with nonobese ones. Thus, the increased risk of VTE among obese pregnant women may not be caused by venous stasis.
How does Fetal Autopsy after Pregnancy Loss or Termination for Anomalies and other Complications Change Recurrence Risk?
Authors: Cassidy Arianna , Herrick Claire , Norton Mary , Ursell Philip , Vargas Juan , Kerns Jennifer
Published: February 2019

Objective Historically, fetal autopsy was common after terminations for anomalies. Previous studies report that fetal autopsy confirms ultrasound findings in the majority of cases. This study aims to examine correlation between prenatal and autopsy diagnoses at University of California, San Francisco (UCSF) and evaluate whether autopsy adds diagnostic information, specifically information that changes risk of recurrence for future pregnancies.

Study Design We conducted a retrospective chart review of all fetal autopsies performed at UCSF between 1994 and 2009. Prenatal diagnosis was compared with autopsy diagnosis; for cases where there was a change in diagnosis, an MFM (maternal-fetal medicine specialist) reviewed the case to assign risk of recurrence before and after autopsy.

Results Overall, there was concordance between prenatal diagnosis and autopsy diagnosis in greater than 91.7% of cases. Autopsy added information that resulted in a change in recurrence risk in 2.3% of cases (n = 9).

Conclusion For the vast majority of cases, there is agreement between prenatal and autopsy diagnosis after pregnancy loss or termination for fetal anomalies. Only a small percentage of autopsies change recurrence risk. This may be useful when counseling women about method of termination and when counseling couples about whether to have an autopsy.
Adrenaline Improves Platelet Reactivity in Ticagrelor-Treated Healthy Volunteers
Authors: Singh Sukhi , Damén Tor , Nygren Andreas , Shams Hakimi Caroline , Ramström Sofia , Dellborg Mikael , Lindahl Tomas , Hesse Camilla , Jeppsson Anders
Published: February 2019

Background Administration of agents that enhance platelet reactivity may reduce the perioperative bleeding risk in patients treated with the adenosine diphosphate (ADP)-receptor antagonist ticagrelor. Adrenaline potentiates ADP-induced aggregation and activation in blood samples from ticagrelor-treated patients, but it has not previously been evaluated in vivo.

Methods Ten healthy male subjects were included in an interventional study. A loading dose of ticagrelor (180 mg) was administered, followed 2 hours later by a gradually increased intravenous adrenaline infusion (0.01, 0.05, 0.10 and 0.15 µg/kg/min; 15 minutes at each step). Blood pressure, heart rate, platelet aggregation (impedance aggregometry), platelet activation (flow cytometry), clot formation (rotational thromboelastometry) and adrenaline plasma concentration were determined before and after ticagrelor administration and at the end of each adrenaline step.

Results Infusion of adrenaline increased ADP-induced aggregation at all doses above 0.01 µg/kg/min. The aggregation increased from median 17 (25−75th percentiles: 14−31) to 25 (21−34) aggregation units (p = 0.012) at 0.10 µg/kg/min. Adrenaline infusion also increased ADP-induced fibrinogen receptor activation (from 29 [22–35] to 46 [38−57%]) and P-selectin expression (from 3.7 [3.0−4.3] to 7.7 [4.7−8.6%]), both p = 0.012. Adrenaline infusion reduced clot formation time (97 [89−110] to 83 [76−90] seconds, p = 0.008) and increased maximum clot firmness (59 [57−60] to 62 [61−64] mm, p = 0.007).

Conclusion Infusion of adrenaline at clinically relevant doses improves in vivo platelet reactivity and clot formation in ticagrelor-treated subjects. Adrenaline could thus potentially be used to prevent perioperative bleeding complications in ticagrelor-treated patients. Studies in patients are necessary to determine the clinical importance of our observations.

Trial Registry Number ClinicalTrials.gov NCT03441412.
Physically defined triple quantum dot systems in silicon on insulator
Authors: Mizokuchi R. , Oda S. , Kodera T.
Published: February 2019

We report characterizations of two types of Si triple quantum dot (TQD) devices with charge sensors, with the aim of integrating spin qubits. The QDs of a single TQD device are connected in line to adjacent QD(s), while all QDs are tunnel-coupled to each other in the other device to form a triangle. Both TQD systems are physically defined on silicon-on-insulator substrates using electron beam lithography and dry etching. From electron transport measurements of each type of TQD system at 4.2 K, we demonstrate the formation of tunnel-coupled TQD systems and the tunability of their electric potentials.
Enhanced optical Kerr nonlinearity of graphene/Si hybrid waveguide
Authors: Feng Qi , Cong Hui , Zhang Bin , Wei Wenqi , Liang Yueyin , Fang Shaobo , Wang Ting , Zhang Jianjun
Published: February 2019

In this work, we experimentally study the optical Kerr nonlinearities of graphene/Si hybrid waveguides with enhanced self-phase modulation. In the case of CMOS compatible materials for nonlinear optical signal processing, Si and silicon nitride waveguides have been extensively investigated over the past decade. However, Si waveguides exhibit strong two-photon absorption (TPA) at telecommunication wavelengths, which leads to a significant reduction of the nonlinear figure-of-merit (FOM). In contrast, a silicon nitride based material system usually suppresses the TPA but simultaneously leads to the reduction of Kerr nonlinearity by one order of magnitude. Here, we introduce a graphene/Si hybrid waveguide, which maintains the optical properties and CMOS compatibility of Si waveguides, while enhancing the Kerr nonlinearity, by transferring over to the top of the waveguides. The graphene/Si waveguides are measured to have an enhanced nonlinear parameter of 510 W−1 m−1, compared with that of the Si waveguide of 150 W−1 m−1. An enhanced nonlinear FOM of 2.48 ± 0.25 has been achieved, which is four times larger than that of the Si waveguide of 0.6 ± 0.1. This work reveals the potential application of graphene/Si hybrid waveguides with high Kerr nonlinearity and FOM for nonlinear all-optical signal processing.
On the characterization of a 1 m long, ultra-precise KB-focusing mirror pair for European XFEL by means of slope measuring deflectometry
Authors: Siewert F. , Buchheim J. , Gwalt G. , Bean R. , Mancuso A. P.
Published: February 2019

Recently, the European X-Ray Free Electron Laser (XFEL) has successfully produced its first X-ray photon pulse trains. This unique photon source will provide up to 27 000 photon pulses per second for experiments in different fields of science. In order to accomplish this, ultra-precise mirrors of dedicated shape are used to guide and focus these photons along beamlines of up to 930 m in length from the source in the undulator section to the desired focal point at an experimental station. We will report on a Kirkpatrick-Baez-mirror pair designed to focus hard-X-rays in the energy range from 3 to 16 keV to a 100 nm scale at the SPB/SFX instrument of the European XFEL. Both mirrors are elliptical cylinder-like shaped. The figure error of these 1 m long mirrors was specified to be better than 2 nm pv in terms of the height domain; this corresponds to a slope error of about 50 nrad rms (at least a best effort finishing is requested). This is essential to provide optimal experimental conditions including preservation of brilliance and wavefront. Such large and precise optics represents a challenge for the required deterministic surface polishing technology, elastic emission machining in this case, as well as for the metrology mandatory to enable a precise characterization of the topography on the mirror aperture. Besides the slope errors, the ellipse parameters are also of particular interest. The mirrors were under inspection by means of slope measuring deflectometry at the BESSY-NOM slope measuring profiler at the Helmholtz Zentrum Berlin. The NOM measurements have shown a slope error of 100 nrad rms on a aperture length of 950 mm corresponding to a residual figure deviation ≤20 nm pv for both mirrors. Additionally we found a strong impact of the mirror support conditions on the mirror shape finally measured. We will report on the measurement concept to characterize such mirrors as well as to discuss the achieved results.
Metal-induced gap states in passivating metal/silicon contacts
Authors: Sajjad Muhammad , Yang Xinbo , Altermatt Pietro , Singh Nirpendra , Schwingenschlögl Udo , De Wolf Stefaan
Published: February 2019

Passivating metal/silicon contacts combine low carrier recombination with low contact resistivities, enabled by a low gap state density at their interface. Such contacts find applications in high-efficiency solar cells. We perform first-principles calculations based on density functional theory to investigate the surface defect and metal-induced gap state density of silicon in close contact with metals (Al and Ag). We confirm that surface hydrogenation fully removes surface-defect gap states of (111)-oriented silicon surfaces. However, the metal-induced gap state density increases significantly when metals are closer than 0.5 nm to such surfaces. These results highlight the importance of the tunneling-film thickness in achieving effective passivating-contact formation.
Distinct characteristics of DNA field effect transistors embedded with marine-derived porphyra-334 under UV illumination
Authors: Chopade Prathamesh , Moh Sang Hyun , Kanade Vinit , Kim Taesung , Kulkarni Atul , Park Sung Ha
Published: February 2019

DNA extracted from salmon has recently attracted the attention of researchers, resulting in applications of DNA in photonic and electronic devices. Porphyra-334, a type of mycosporine-like amino acids (MAAs), also plays an important role in photoprotection for a variety of marine organisms including bacteria and algae. Although MAA and DNA molecules have been intensively studied, fabrication methodology and applicability of MAA-embedded DNA complexes for physical applications have been seldom discussed due to incompatibility between biological samples and physical platform. Here, Porphyra-334 embedded DNA was investigated to understand its electrical transport property with the aid of silicon nanowire/nanoribbon field effect transistors (NW/NR FETs). Its chemical stability was determined by cyclic voltammetry upon illumination of UV light. The current of DNA-SiNW FET was enhanced by the addition of Porphyra-334 and upon illumination of UV light. Conductivities of PDNA-SiNW FET compared to SiNW FET were increased up to ∼70% at dark and ∼40% under UV light due to the presence of Porphyra-334 and excess injection of charge carriers in Porphyra-334 embedded DNA generated by absorbing UV light, respectively. The addition of Porphyra-334 in DNA-SiNR FET lowered its energy level and resulted in large threshold voltage shift towards the negative scale. In addition, its electrochemical property was studied by cyclic voltammetry and impedance spectroscopy. Porphyra-334 in DNA solution which inhibited oxidation of DNA showed relatively lower current indicating high electrochemical stability and decrease of resistance compared to pristine DNA solution based on results of impedance spectroscopy.
Mutually polarizable QM/MM model with
in situ
optimized localized basis functions
Authors: Dziedzic Jacek , Head-Gordon Teresa , Head-Gordon Martin , Skylaris Chris-Kriton
Published: February 2019

We extend our recently developed quantum-mechanical/molecular mechanics (QM/MM) approach [Dziedzic et al., J. Chem. Phys. 145, 124106 (2016)] to enable in situ optimization of the localized orbitals. The quantum subsystem is described with onetep linear-scaling density functional theory and the classical subsystem – with the AMOEBA polarizable force field. The two subsystems interact via multipolar electrostatics and are fully mutually polarizable. A total energy minimization scheme is employed for the Hamiltonian of the coupled QM/MM system. We demonstrate that, compared to simpler models using fixed basis sets, the additional flexibility offered by in situ optimized basis functions improves the accuracy of the QM/MM interface, but also poses new challenges, making the QM subsystem more prone to overpolarization and unphysical charge transfer due to increased charge penetration. We show how these issues can be efficiently solved by replacing the classical repulsive van der Waals term for QM/MM interactions with an interaction of the electronic density with a fixed, repulsive MM potential that mimics Pauli repulsion, together with a modest increase in the damping of QM/MM polarization. We validate our method, with particular attention paid to the hydrogen bond, in tests on water-ion pairs, the water dimer, first solvation shells of neutral and charged species, and solute-solvent interaction energies. As a proof of principle, we determine suitable repulsive potential parameters for water, K+, and Cl−. The mechanisms we employed to counteract the unphysical overpolarization of the QM subsystem are demonstrated to be adequate, and our approach is robust. We find that the inclusion of explicit polarization in the MM part of QM/MM improves agreement with fully QM calculations. Our model permits the use of minimal size QM regions and, remarkably, yields good energetics across the well-balanced QM/MM interface.
Reduction of recording noise caused by nano-scale variations in Curie temperature
Authors: Liu Zengyuan , Huang Pin-Wei , Ju Ganping , Victora R. H.
Published: February 2019

Heat-Assisted Magnetic Recording (HAMR) is expected to be the next-generation magnetic recording technology: it is designed to meet increasing higher areal density demands from cloud storage. Until now, there are no feasible solutions to address nm-scale Curie temperature variance in FePt-based single layer media. This variance is the leading noise source, and thus limits further development of HAMR technology. Here, we describe a superparamagnetic write process that can greatly mitigate the impact of Curie temperature variance by recording information at the blocking temperature of the magnetic material. To demonstrate the benefits of this write process, we employ a bilayer structure with a superparamagnetic write layer and FePt as a long-term storage layer. By developing the theory behind the recording mechanism, we are able to introduce design rules addressing the importance of elevated Curie temperature in the write layer and optimization of quantum mechanical coupling between the two functional layers.
Shear strain-induced anisotropic domain evolution in mixed-phase BiFeO3 epitaxial films
Authors: Xu Han , Chen Zuhuang , Zhang Xiaoyi , Dong Yongqi , Hong Bin , Zhao Jiangtao , Chen Lang , Das Sujit , Gao Chen , Zeng Changgan , Wen Haidan , Luo Zhenlin
Published: February 2019

Understanding and controlling the domain evolution under external stimuli in multiferroic thin films is critical to realizing nanoelectronic devices, including for non-volatile memory, data storage, sensors, and optoelectronics. In this article, we studied the shear-strain effect on the domain evolution with temperature in highly strained BiFeO3 thin films on rhombohedral LaAlO3 substrates using a high-resolution synchrotron X-ray diffraction three dimensional-reciprocal space mapping (3D-RSM) technique. The results revealed significant biaxial, anisotropic, evolution behaviors of the mixed-phase (MC + R′/T′ phases) BiFeO3 ferroelectric domains along the in-plane [100] and [010] axes. These biaxial, anisotropic, evolution behaviors were attributed to the shear-strain-modulated transition pathways of the mixed-phase ferroelectric domains. This viewpoint was further verified in the BiFeO3/LaSrAlO4 (001) system in which no anisotropic evolution behaviors of the mixed-phase domains were found. This work sheds light on the quantitative analysis of domain evolution in multi-domain systems and demonstrates that the shear-strain effect could act as an effective tool to manipulate the domain behavior and control novel functionalities of ferroelectric thin films.
Stabilizing zero-field skyrmions in Ir/Fe/Co/Pt thin film multilayers by magnetic history control
Authors: Duong Nghiep Khoan , Raju M. , Petrović A. P. , Tomasello R. , Finocchio G. , Panagopoulos Christos
Published: February 2019

We present a study of the stability of room-temperature skyrmions in [Ir/Fe/Co/Pt] thin film multilayers, using the First Order Reversal Curve (FORC) technique and magnetic force microscopy (MFM). FORC diagrams reveal irreversible changes in magnetization upon field reversals, which can be correlated with the evolution of local magnetic textures probed by MFM. Using this approach, we have identified two different mechanisms—(1) skyrmion merger and (2) skyrmion nucleation followed by stripe propagation—which facilitate magnetization reversal in a changing magnetic field. Analysing the signatures of these mechanisms in the FORC diagram allows us to identify magnetic “histories”—i.e., precursor field sweep protocols—capable of enhancing the final zero-field skyrmion density. Our results indicate that FORC measurements can play a useful role in characterizing spin topology in thin film multilayers and are particularly suitable for identifying samples in which skyrmion populations can be stabilized at zero field.
A reduced model of neutral-plasma interactions in the edge and scrape-off-layer: Verification comparisons with kinetic Monte Carlo simulations
Authors: Russell D. A. , Myra J. R. , Stotler D. P.
Published: February 2019

The 2D scrape-off-layer turbulence code (SOLT) is extended to include neutral-plasma interactions. A Boltzmann equation is derived for the evolution of the bi-normally averaged neutral distribution function, G(x,vx,t), in the radial dimension, and this evolution is included in the new scrape-off-layer turbulence code (nSOLT). Neutral-plasma interactions are mediated by charge-exchange (CX) and ionization rates based on poloidally averaged plasma density and temperature. Good agreement is obtained between asymptotically stationary neutral density profiles from nSOLT simulations and those previously obtained from the Monte Carlo neutral transport code DEGAS 2, for time-averaged NSTX H-mode plasma profiles. The sensitivity of the nSOLT neutral profiles to atomic physics parameters, with and without CX physics, is included in the comparison. In addition, nSOLT simulations that evolve the plasma in 1D, using radial diffusion as a proxy for turbulent (blob) transport, illustrate the convergence to a self-consistent neutral-plasma equilibrium sustained by a neutral source at the far-scrape-off-layer boundary and plasma heating in the core; equilibria consistent with typical NSTX Ohmic L-mode plasmas are described.
Simulation of three-dimensional bubble formation and interaction using the high-density-ratio lattice Boltzmann method
Authors: Chen Guo-Qing , Huang Xiao , Zhang A-Man , Wang Shi-Ping
Published: February 2019

The growth and departure of bubbles from an orifice and their interactions is a common phenomenon. In this paper, a multiphase flow model based on the lattice Boltzmann method is constructed to study this process, with an improved interface capture method being adopted to deal with the high density ratio between liquid and gas. A virtual layer is added outside the computational domain to handle the boundary condition at the orifice. The processes of bubble formation and interaction are well simulated by the model, and the results agree well with those of theoretical calculations for single-bubble formation and departure diameter and period. Bubble formation is controlled by the inertial force of the gas, buoyancy, surface tension, and the viscous force of the liquid. The inertial force of the gas and buoyancy promote bubble growth and departure, respectively, while the surface tension controls bubble deformation and the viscous force affects the necking process. Increases in both the orifice size and the gas outflow velocity can enlarge the departure diameter of the bubble, but the orifice size plays a more important role here. Both of these two parameters have obvious effects on the departure period. For the interaction of bubbles growing from orifices with the same or different sizes, different coalescence categories are distinguished according to the stage of coalescence, and the characteristics of the coalescence process are considered in terms of their dependence on surface tension, viscous force, and buoyancy. Finally, the departure diameter and departure period of coalesced bubbles are studied under the different coalescence conditions.
Characterization of a BCZT/LCMO/BCZT laminated composite fabricated by plasma-activated sintering
Authors: Li Songbin , Wang Chuanbin , Shen Qiang , Zhang Lianmeng
Published: February 2019

This paper reports on a trilayer Ba0.85Ca0.15Zr0.1Ti0.9O3/La0.67Ca0.33MnO3/Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT/LCMO/BCZT) laminated composite fabricated using plasma-activated sintering. The interfacial structure and the electrical, ferromagnetic, and magnetoelectric properties of the laminated composite are characterized in detail. The laminated composite is found to be highly dense with high-quality interfacial bonding, and its dielectric properties are superior to those of BCZT. The characteristics of the ferroelectric and ferromagnetic properties demonstrate the multiferroic nature of the laminated composite, which exhibits a maximum magnetoelectric coefficient of 1.07 mV/cm Oe.
Experimental and numerical study on capillary flow along deflectors in plate surface tension tanks in microgravity environment
Authors: Chen Shangtong , Han Zhiyi , Duan Li , Kang Qi
Published: February 2019

Surface tension tanks are the most widely used satellite propellant tanks, which use liquid surface tension for liquid transportation and gas-liquid separation to provide pure propellant for thruster. As the second generation surface tension tank, the plate type tank has characteristics of simple structure, easy processing and high reliability, and represents development direction of surface tension tanks. In this paper, drop tower experiments are used to investigate transfer speed of deflectors in plate type tanks, and corresponding numerical simulation is carried out in Fluent with Volume of Fluid method.
Density and time scaling effects on the velocity autocorrelation function of quantum and classical dense fluid para-hydrogen
Authors: Bellissima S. , Neumann M. , Bafile U. , Colognesi D. , Barocchi F. , Guarini E.
Published: February 2019

We report the results of a ring polymer molecular dynamics study of the Kubo velocity autocorrelation function of a quantum fluid as para-hydrogen aimed at the comparison with its classical counterpart. Quite different density conditions were considered for both the classical and quantum cases, in order to compare the two systems before and after the dynamical crossover typically undergone by the velocity autocorrelation function (VAF) of fluids at densities around the triple point, where the shape of the function changes from a monotonic to an oscillatory behavior with a negative minimum. A detailed study of the phase diagram of classical para-hydrogen was necessary for a reasonable choice of the classical states to be taken into consideration, in the spirit of the classical principle of corresponding states. The shape of the quantum and classical VAF was thoroughly analyzed, exhibiting at all studied densities clear differences that might be taken as evidence of quantum effects. We show that these differences are substantially reduced by applying a state-dependent time scaling with respect to a reference time identified with the inverse of the collision rate. An even better coincidence in shape is found by comparing the two systems at slightly non-corresponding reduced densities, suggesting that the quantum system behaves almost like the classical one, but at systematically less dense reduced states of the latter. We also find an unexpected and quite interesting density trend of the collision rate of both classical and quantum para-hydrogen, which accounts for the effectiveness of the scaling throughout the explored density range. The mean kinetic energy and the diffusion coefficients are also discussed in some detail.
Numerical simulation and measurement analysis of the temperature field of artificial freezing shaft sinking in Cretaceous strata
Authors: Yao Zhishu , Cai Haibing , Xue Weipei , Wang Xiaojian , Wang Zongjin
Published: February 2019

Targeting the challenging analysis of the temperature field of the artificial freezing shaft sinking projects in Cretaceous strata, this study used the Hongqinghe air shaft freezing project as an example to perform a numerical simulation and measurement analysis of the temperature field of shaft sinking via the artificial freezing method in Cretaceous strata. First, the thermal physical parameters and mechanical properties of frozen Cretaceous rock were measured in the lab. Based on the engineering geological conditions and test parameters, the Hongqinghe air shaft freezing parameters were designed, and the preliminary scheme of the freezing project was obtained, in which a single ring of freezing holes was arranged in Cretaceous strata, the freezing wall had a design thickness of 3.7 m, and the average temperature was -12°C. Next, a numerical model for the temperature field of the freezing project was established to predict and analyze the effective thickness, average temperature, and shaft wall temperature of the frozen wall at different depths of shaft excavation. Finally, a comparison and analysis of field temperatures measured at the inspection holes and shaft walls showed that the numerical simulation results generally agreed with the field measurements. The field measurements showed that at the initial stage of freezing, the cooling rates of fine-, medium- and coarse-grained sandstones were 0.364 °C/d, 0.397 °C/d and 0.440 °C/d, respectively. Informatized construction enabled the air shaft freezing project in the Hongqinghe coal mine to be completed successfully.
Complete determination of elastic stiffness coefficients and local symmetry breaking in the paraelectric barium titanate
Authors: Lee Jeong Woo , Ko Jae-Hyeon , Roleder Krystian , Rytz D.
Published: February 2019

The temperature dependence of all independent elastic stiffness coefficients of cubic BaTiO3 was determined over a wide temperature range from 400 °C to the Curie point (Tc ∼ 131 °C) by using Brillouin light scattering spectroscopy. Among the two elastic eigen-modes corresponding to the two measured transverse acoustic waves, (C11-C12)/2 showed a large softening in the paraelectric phase, while the change in C44 was very small. This result caused the elastic anisotropy A, defined as 2C44/(C11-C12), to increase from ∼2.1 to ∼2.7 upon cooling toward the phase transition temperature. The large elastic anisotropy was attributed to the tetragonal instability and the associated anisotropic polarization fluctuations of precursor polar clusters formed by the correlated Ti motions. The elastic anisotropy was fitted by using the Curie-Weiss law resulting in a significant deviation in a certain temperature range between Tc and ∼Tc + 50 °C, similar to the dielectric permittivity.
Stabilizing the isolated Sn2Bi nanosheet and tailoring its electronic structure by chemical functionalization: A computational study
Authors: Ding Yi , Wang Yanli
Published: February 2019

Very recently, a two-dimensional nanomaterial, the Sn2Bi nanosheet, has been synthesized on a silicon wafer. Here, utilizing first-principles calculations, we explore the structural stability and electronic property of the free-standing Sn2Bi nanosheet. Different from the experimentally supported one, we find that the isolated Sn2Bi nanosheet is a metal and suffers from dynamical instability. Its structural stability can be greatly enhanced by surface hydrogenation, which can completely eliminate the soft modes from the high-buckled tricoordinate Sn atoms. Both the single-side and double-side hydrogenated Sn2Bi (s-/d-H-Sn2Bi) nanosheets possess robust energetic, dynamical, and thermal stabilities and exhibit a semiconducting behavior akin to the supported Sn2Bi system. In particular, the band edge of the s-H-Sn2Bi nanosheet can saddle the redox potential of water under a strong alkaline condition, and its analogue by the iodization (s-I-Sn2Bi) is even suitable for photocatalytic water splitting under the pH neutral condition. Moreover, these functionalized systems exhibit high solar-to-hydrogen efficiencies, which reach up to 18% and 36% in the s-H-Sn2Bi and s-I-Sn2Bi nanosheets, respectively. Our study demonstrates that the functionalized Sn2Bi nanosheets have robust structural stabilities and promising electronic properties for potential applications in nano-energy and nano-electrics.
A study on the transferability of the sigma enlarging bridge function for an accurate evaluation of solvation free energy: The case of homonuclear Lennard-Jones diatomic solute solvated in a Lennard-Jones monatomic solvent
Authors: Miyata Tatsuhiko , Yabuki Naoya
Published: February 2019

We study the applicability of sigma enlarging bridge (SEB) function to a homonuclear Lennard-Jones (LJ) diatomic solute molecule solvated in an LJ monatomic solvent, where the SEB was originally proposed for a monatomic solute molecule to improve the accuracy of the solvation free energy (SFE) [T. Miyata, Bull. Chem. Soc. Jpn. 90, 1095 (2017)]. Our interest is focused on the transferability of the SEB parameter, which is a parameter included in the SEB function. We employ the two-dimensional Ornstein-Zernike (OZ) theory. Hypernetted chain (HNC), Kovalenko-Hirata (KH) and Percus-Yevick (PY) closures are considered. The HNC closure with the SEB correction (SEB-HNC) and the counterpart for the KH closure (SEB-KH) are also examined in terms of the SFE. It is found that by comparing with the molecular dynamics simulation, the SFE is overestimated under both HNC and KH closures, whereas it tends to be underestimated under PY closures. These results are similar to those obtained for systems of LJ monatomic solute molecules. Both the SEB-HNC and the SEB-KH closures provide quite an accurate SFE, when the SEB parameter values that were originally evaluated for a monatomic solute molecule are applied to the homonuclear LJ diatomic solute. This indicates that the SEB parameter is transferable. The transferability of the SEB parameter is also confirmed in terms of the angular-dependent one-dimensional distribution function, which is obtained from the two-dimensional distribution function. The validity of the partial molar volume correction is also discussed by examining the dependence of the SFE errors on the solute volume.