bluuebunny/crossref_metadata_2025 huggingface dataset:
Fingerprint identification of copper ions with absorption and emission dual-mode responses by N,S co-doped red carbon dots
Authors: Ju Bo , Zhang Ting , Li Song , Liu Jun , Zhang Weiran , Li Minjie , Zhang Sean Xiao-An
Published: November 2018

Highly selective and sensitive Cu2+-based sensors have been successfully developed by N,S co-doped red emissive carbon dots with absorption and emission dual-mode recognition strategies.
A reusable fluorescent sensor from electrosynthesized water-soluble oligo(1-pyrenesulfonic acid) for effective detection of Fe3+
Authors: Jian Nannan , Lin Kaiwen , Guo Bin , Zhang Ge , Liu Ximei , Zou Lie , Lu Baoyang , Xu Jingkun
Published: November 2018

Electrosynthesized oligo(1-pyrenesulfonic acid) displays high selectivity, low detection limit and outstanding reversibility in the detection of Fe3+ in aqueous solution.
Photoinduced synthesis of allylic sulfones using potassium metabisulfite as the source of sulfur dioxide
Authors: Zhang Jun , Zhou Kaida , Qiu Guanyinsheng , Wu Jie
Published: November 2018

Synthesis of allylic sulfones through a photoinduced three-component reaction of aryl/alkyl halides, potassium metabisulfite, and allylic bromides under ultraviolet irradiation at room temperature is developed. Diverse allylic sulfones are generated in moderate to good yields.
Retracted Article: Long non-coding RNA KCNQ1OT1 promotes osteosarcoma progression by increasing β-catenin activity
Authors: Zhang Changsheng , Du Shengyang , Cao Lei
Published: November 2018

Long non-coding RNA KCNQ1OT1 has been associated with the development of different types of cancers.
Solvent-mediated length tuning of ultrathin platinum–cobalt nanowires for efficient electrocatalysis
Authors: Xu Hui , Wei Jingjing , Zhang Min , Wang Caiqin , Shiraishi Yukihide , Guo Jun , Du Yukou
Published: November 2018

A solvent-mediated method has been developed for the synthesis of ultrathin Pt3Co1 nanowires with different lengths. And systematic electrochemical measurements revealed that the electrocatalytic performances were enhanced with increasing length.
Bifunctional scaffolds for the photothermal therapy of breast tumor cells and adipose tissue regeneration
Authors: Wang Xiuhui , Zhang Jing , Li Jingchao , Chen Ying , Chen Yazhou , Kawazoe Naoki , Chen Guoping
Published: November 2018

Bifunctional composite scaffolds of gold nanorods and gelatin can ablate tumor cells and promote the adipogenic differentiation of stem cells.
Unidirectional and crystalline organic semiconductor microwire arrays by solvent vapor annealing with PMMA as the assisting layer
Authors: Zhu Xiaoting , Wang Qingqing , Tian Xinzi , Zhang Xiaotao , Feng Yiyu , Feng Wei , Li Rongjin , Hu Wenping
Published: November 2018

Unidirectional and crystalline organic semiconductor microwire arrays were obtained by solvent vapor annealing with PMMA as the assisting layer.
Millimeter-wave absorption properties of BaTiO3/Co3O4composite powders controlled by high-frequency resonances of permittivity and permeability
Authors: Tian Wei , Ma Ruoyang , Gu Jian , Wang Zongrong , Ma Ning , Du Piyi
Published: November 2018

Millimeter-wave resonance of permittivity–permeability-contributed double absorption peaks in BaTiO3/Co3O4, exhibiting RL of ∼−40 dB and a bandwidth of 5 GHz around 35 GHz.
Direct observation of adsorption kinetics on clays by cation–π interaction-triggered aggregation luminescence
Authors: Zhong Jinpan , Cui Xingyu , Guan Weijiang , Lu Chao
Published: November 2018

Schematic representation of cation–π interaction-triggered aggregation luminescence for direct observation of adsorption kinetics on clays.
Evolution of highly efficient rare-earth free Cs(1−x)RbxVO3phosphors as a single emitting component for NUV-based white LEDs
Authors: Pavitra E. , Seeta Rama Raju G. , Krishna Bharat L. , Park Jin Young , Kwak Cheol Hwan , Chung Jong Won , Han Young-Kyu , Huh Yun Suk
Published: November 2018

A WLED with high luminous efficacy is fabricated using rare-earth free CsVO3:0.25Rb as a single emitting compound for solid-state lighting applications.
DNA-linked inhibitor antibody assay (DIANA) as a new method for screening influenza neuraminidase inhibitors
Authors: Kožíšek Milan , Navrátil Václav , Rojíková Kateřina , Pokorná Jana , Berenguer Albiñana Carlos , Pachl Petr , Zemanová Jitka , Machara Aleš , Šácha Pavel , Hudlický Jason , Císařová Ivana , Řezáčová Pavlína , Konvalinka Jan
Published: November 2018

Influenza neuraminidase is responsible for the escape of new viral particles from the infected cell surface. Several neuraminidase inhibitors are used clinically to treat patients or stockpiled for emergencies. However, the increasing development of viral resistance against approved inhibitors has underscored the need for the development of new antivirals effective against resistant influenza strains. A facile, sensitive, and inexpensive screening method would help achieve this goal. Recently, we described a multiwell plate-based DNA-linked inhibitor antibody assay (DIANA). This highly sensitive method can quantify femtomolar concentrations of enzymes. DIANA also has been applied to high-throughput enzyme inhibitor screening, allowing the evaluation of inhibition constants from a single inhibitor concentration. Here, we report the design, synthesis, and structural characterization of a tamiphosphor derivative linked to a reporter DNA oligonucleotide for the development of a DIANA-type assay to screen potential influenza neuraminidase inhibitors. The neuraminidase is first captured by an immobilized antibody, and the test compound competes for binding to the enzyme with the oligo-linked detection probe, which is then quantified by qPCR. We validated this novel assay by comparing it with the standard fluorometric assay and demonstrated its usefulness for sensitive neuraminidase detection as well as high-throughput screening of potential new neuraminidase inhibitors.
A Survey of Clinician Decision Making When Identifying Swallowing Impairments and Determining Treatment
Authors: Vose Alicia K. , Kesneck Sara , Sunday Kirstyn , Plowman Emily , Humbert Ianessa
Published: November 2018

Purpose

Speech-language pathologists (SLPs) are the primary providers of dysphagia management; however, this role has been criticized with assertions that SLPs are inadequately trained in swallowing physiology (Campbell-Taylor, 2008). To date, diagnostic acuity and treatment planning for swallowing impairments by practicing SLPs have not been examined. We conducted a survey to examine how clinician demographics and swallowing complexity influence decision making for swallowing impairments in videofluoroscopic images. Our goal was to determine whether SLPs' judgments of swallowing timing impairments align with impairment thresholds available in the research literature and whether or not there is agreement among SLPs regarding therapeutic recommendations.

Method

The survey included 3 videofluoroscopic swallows ranging in complexity (easy, moderate, and complex). Three hundred three practicing SLPs in dysphagia management participated in the survey in a web-based format (Qualtrics, 2005) with frame-by-frame viewing capabilities. SLPs' judgments of impairment were compared against impairment thresholds for swallowing timing measures based on 95% confidence intervals from healthy swallows reported in the literature.

Results

The primary impairment in swallowing physiology was identified 67% of the time for the easy swallow, 6% for the moderate swallow, and 6% for the complex swallow. On average, practicing clinicians mislabeled 8 or more swallowing events as impaired that were within the normal physiologic range compared with healthy normative data available in the literature. Agreement was higher among clinicians who report using frame-by-frame analysis 80% of the time. A range of 19–21 different treatments was recommended for each video, regardless of complexity.

Conclusions

Poor to modest agreement in swallowing impairment identification, frequent false positives, and wide variability in treatment planning recommendations suggest that additional research and training in healthy and disordered swallowing are needed to increase accurate dysphagia diagnosis and treatment among clinicians.
Hyperspectral image clustering via sparse dictionary‐based anchored regression
Authors: Huang Nan , Xiao Liang
Published: November 2018

Clustering for hyperspectral images (HSIs) is a very challenging task because HSIs usually have large spectral variability, high dimensionality, and complex structures. The main issue of this study is to develop an improved sparse subspace clustering (SSC) method for HSIs. As an extension of spectral clustering, SSC algorithm has achieved great success; however, the direct self‐representation dictionary which is created by raw samples has poor representation power and also the widely used dictionary learning (DL) such as K‐Singular Value Decomposition (K‐SVD) faces with the problems of high computational complexity. In this study, the authors propose a novel HSI clustering method based on sparse DL and anchored regression. The proposed method follows three stages: (i) sparse DL; (ii) anchored subspace construction and regression; and (iii) representation‐based spectral clustering. Specifically, we adopt a fast sparse DL method under a double sparsity constrained optimising model to capture the intrinsic HSIs. To establish a compact subspace for collaborative representation, we present an anchored subspace construction method by using atoms clustering and grouping methods. Owing to the anchored subspace, we can fast compute the representation coefficients with a predefined projection matrix. Experimental results demonstrate that the proposed method achieves the best performance for the HSIs clustering.
Dynamic evolution control based power sharing method for hybrid energy storage system
Authors: Manandhar Ujjal , Wang Benfei , Ukil Abhisek , Gooi Hoay Beng
Published: November 2018

In this study, a new dynamic evolution control (DEC) based power sharing method is proposed for hybrid energy storage system (HESS) with photovoltaic in the isolated DC grid application. The proposed control approach solves the current controller conflict problem in HESS and provides faster DC link voltage restoration. A DEC method is implemented to control the battery current, supercapacitor current and DC link voltage. A DEC method uses a predictive term and feed‐forward term to regulate the current and voltage in the system. In the proposed control method, the battery supports the average power demand in the system. The supercapacitor supports the transient power demand, uncompensated power from the battery and error voltage term. Thus, it results in faster DC link voltage restoration and less stress in the battery system. The detailed design of the system parameters and controller parameters is presented in this study. Simulation and experimental studies validate the effectiveness of the proposed control method.
Vertical double diffused MOSFET with step HK insulator improving electric field modulation
Authors: Duan Baoxing , Xie Fengyun , Shi Tongtong , Yang Yintang
Published: November 2018

A novel step high‐k metal–oxide–semiconductor field‐effect transistor (step HK‐MOSFET) is designed with the step high‐k insulator based on the HK‐MOSFET concept for the first time. In the off‐state, the step HK insulator enhances the lateral field component in the drift region due to the new electric field peak, which increases the depletion of the drift region and leading to the low specific on‐resistance (Ron, sp) of step HK‐MOSFET compared with the conventional HK‐MOSFET. Meanwhile, the various thicknesses of the HK insulator modulates the vertical electric field distribution in the drift region, which increases the breakdown voltage (BV) of step HK‐MOSFET compared with the conventional vertical double diffused MOSFET and HK‐MOSFET. The results show that the simulated BV of step HK‐MOSFET is increased from 639 V of the conventional HK‐MOSFET to 736 V with the same drift region length of 42 μm or decreased the requirement of permittivity for the HK region to 120 ɛ0 from 230 ɛ0 with the same BV of 600 V.
Étude de la vitesse de recul de la canine supérieure après corticotomie alvéolaire
Authors: Mezari A. , Si Ahmed F.
Published: November 2018

Introduction : l'objectif de cette étude est d'évaluer l'efficacité de la corticotomie alvéolaire sur la vitesse du recul de la canine supérieure comparé au traitement conventionnel. Matériel et méthode : L'échantillon était constitué de 30 patients avec un âge moyen de 21 ± 2 ans dont le traitement orthodontique nécessitait le recul des canines supérieures après extraction des premières prémolaires supérieures. Les sujets étaient répartis en deux groupes, l'un recevant un traitement orthodontique assisté par corticotomie alvéolaire, l'autre recevant un traitement conventionnel. La vitesse de recul de la canine supérieure a été évaluée en mesurant la distance entre la canine et la deuxième prémolaire supérieure dans les deux groupes, à 2 mois puis à 4 mois du recul canin. Les résultats ont révélé que cette vitesse était significativement plus élevée dans le groupe expérimental comparé au groupe contrôle et ce deux fois plus à deux mois du recul canin, puis diminuant à 1,25 fois plus élevée à 4 mois. Conclusion : la corticotomie alvéolaire accélère le déplacement dentaire lors du recul des canines supérieures.
Strategien zur Überwindung der erworbenen EGFR-TKI-Resistenz durch T790M spezifische Substanzen am Beispiel von Osimertinib
Authors: Griesinger F. , Radke S. , Lüers A. , Deschler-Baier B. , Kimmich M. , Sebastian M. , Schulz C. , Brugger W. , Wiewrodt R. , Pirker R. , Früh M. , Gautschi O. , Wolf J.
Published: November 2018

Die Resistenzbildung gegenüber der 1. und 2. Generation von Tyrosinkinase-Inhibitoren (TKIs) des epidermalen Wachstumsfaktors (EGFR) stellt bei der Behandlung von Patienten mit nicht kleinzelligem Lungenkarzinom, die eine aktivierende Mutation im EGFR aufweisen, ein großes Problem dar. Drittgenerations-EGFR-TKIs richten sich sowohl gegen aktivierende als auch gegen die Resistenz-vermittelnde T790M-Mutation. EGFR-TKIs der 3. Generation zeigen in klinischen Studien bei T790M-positiven Patienten relevante Wirksamkeit bei meist milden bis moderaten klassenspezifischen Nebenwirkungen. Molekularpathologischen Analysen kommt bei der Entscheidung zur Therapie mit Drittgenerations-EGFR-TKIs eine bedeutsame Rolle zu. In dieser Übersichtsarbeit wird der aktuelle Entwicklungsstand von Drittgenerations-EGFR-TKIs dargestellt mit einem Schwerpunkt auf Osimertinib, dem ersten und bislang einzigen in Deutschland zugelassenen Wirkstoff dieser Klasse. Zudem wird die Relevanz einer molekularen Diagnostik an Tumorgewebe bzw. an zirkulierender Tumor-DNA diskutiert.
Stimm- und Kehlkopfveränderungen im Alter (Presbyphonie und
Presbylarynx)
Authors: Angerstein Wolfgang
Published: November 2018

Etwa 20 % der über 60-Jährigen weisen eine Altersstimmstörung (Presbyphonie) auf,
die oftmals von Presbyakusis (Altersschwerhörigkeit), Presbyphagie
(Schluckstörungen im Alter), Presbyvertigo (Altersschwindel) und/oder Presbyopie
(Alterssichtigkeit) begleitet wird.

Presbyphonie betrifft die Singstimme häufiger, früher und deutlicher als die
Sprechstimme. Aber nicht nur Qualität und Belastbarkeit von Sing- und
Sprechstimme werden beeinträchtigt, auch der Atemantrieb wird durch die
eingeschränkte Lungenfunktion schwächer. Durch das Absenken des Kehlkopfes
verändern sich bei Senioren zudem die Resonanzverhältnisse im Ansatzrohr, und
das Aspirationsrisiko steigt.

Die stimmlichen Einbußen beruhen auf morphologischen Altersveränderungen des
Kehlkopfes (Prebylarynx), die sowohl das ektolaryngeale Kehlkopfskelett als auch
die endolaryngealen Weichteile (insbesondere die Stimmlippen) betreffen.

Der Vokalismuskel atrophiert und wird hypoton, was zu einer
spindelförmig-ovalären Glottisschlussinsuffizienz mit Luftverlust bei Phonation
führt. Die Schleimhäute trocknen aus im Sinne einer Laryngitis sicca.

Bei der Stimmrehabilitation im Alter müssen allgemeine und speziell auf die
Stimme bezogene Behandlungsoptionen unterschieden werden: Zu den allgemeinen
Therapieansätzen gehört die Mitbehandlung internistischer und neurologischer
Grunderkrankungen (z. B. Reflux, neurodegenerative oder zerebrovaskuläre
Erkrankungen) – auch Nebenwirkungen von Medikamenten müssen beachtet werden. Ein
gesunder Lebensstil ohne Noxen begünstigt den Funktionserhalt von Phonations-
und Atemorganen. Stimmtherapeutisch kommen sowohl Tonisierungsübungen zur
Verbesserung des phonatorischen Glottisschlusses als auch detonisierende
Entspannungsübungen zum Abbau supraglottischer hyperfunktioneller
Pressmechanismen in Betracht. In Einzelfällen mit großem Glottisspalt bei
Phonation kann eine phonochirurgische Stimmlippenaugmentation den Glottisschluss
verbessern und somit die Stimme kräftigen. Stimmhygienische Maßnahmen (z. B.
regelmäßiges Befeuchten der Atemwege) ergänzen das Stimmtraining.

Singen im Alter hat sowohl psychosozial (Steigerung des Wohlbefindens und der
sozialen Teilhabe) als auch immunologisch (Anstieg des IgA im Speichel) positive
Effekte.
Die Deutsche Dermatologische Akademie und ihre Zertifikate
Authors: Fritz K.
Published: November 2018

Neben Facharzt- und Zusatzbezeichnungen der Ärztekammern gibt es eine Fülle von Spezialkenntnissen, die mit den offiziellen Titeln nicht abgebildet werden.

Qualifikationsbelege in Form von Zertifikaten können als Kompetenznachweis gegenüber hilfesuchenden Patienten sowie in den Medien Bedeutung haben, wie auch in juristischen Fragen wie Haftung, für die Kostenerstattung und zum Marketing genutzt werden.

Hierzu wurden in der DDA (Deutsche Dermatologische Akademie) eine Reihe von Themen identifiziert, die für solche Zusatzweiterbildungen und Zertifizierungen von Interesse sind, für die nun Curricula existieren und Fortbildungsveranstaltungen danach ausgerichtet werden können. Nach ca. 10 Jahren sollte eine Rezertifizierung erfolgen. Auch unser Assistenzpersonal soll von diesen Weiterbildungen profitieren, daher werden spezielle Curricula und Zertifikate auch für sie aufgelegt.
Oropharynx-Karzinom-CT: prognostische Bedeutung der
extranodalen Ausbreitung
Authors: Güldner Christian
Published: November 2018

Patel MR et al. Radiographic Imaging Does Not Reliably Predict Macroscopic
Extranodal Extension in Human Papilloma Virus-Associated Oropharyngeal Cancer.
ORL 2018; 80: 85–95

Amerikanische Radiologen und Fachärzte für Otorhinolaryngologie evaluierten
bei Patienten mit Oropharynx-Plattenepithelkarzinomen (OPSCC) die
Genauigkeit der präoperativen kontrastmittelverstärkten Computertomographie
(CECT), um die extranodale Ausdehnung (ENE) (> 2 mm) zu
prognostizieren.
Sexueller Missbrauch an Kindern – Entwicklungen im Hell- und Dunkelfeld seit 1953 und Implikationen für das Gesundheitswesen
Authors: Horten Barbara , Dölling Dieter , Hermann Dieter , Kruse Andreas , Schmitt Eric , Bannenberg Britta , Salize Hans-Joachim , Dreßing Harald
Published: November 2018

Daten zum sexuellen Missbrauch an Kindern können zum einen über die Hellfeldstatistiken gewonnen und zum anderen durch Dunkelfeldforschung erhoben werden. Der vorliegende Beitrag befasst sich mit der längsschnittlichen Entwicklung der Delikte in den vergangenen 63 Jahren in Deutschland. Die Straftaten des sexuellen Missbrauchs von Kindern gemäß § 176 StGB weisen in der Polizeilichen Kriminalstatistik (PKS) seit Veröffentlichung der PKS 1953–2016 einen Rückgang der Häufigkeitszahlen auf. Die Ergebnisse aus der Dunkelfeldforschung sind uneinheitlich, sprechen aber teilweise auch für einen Rückgang. Die Bedeutung dieser Befunde für die Präventionsarbeit und gesundheitspolitische Aktivitäten wird diskutiert.
Organocatalytic Group Transfer Reactions with Hypervalent Iodine­ Reagents
Authors: Kalek Marcin , Ghosh Manoj , Rajkiewicz Adam
Published: November 2018

In recent years, a plethora of synthetic methods that employ hypervalent iodine compounds donating an atom or a group of atoms to an acceptor molecule have been developed. Several of these transformations utilize organocatalysis, which complements well the economic and environmental advantages offered by iodine reagents. This short review provides a systematic survey of the organocatalytic approaches that have been used to promote group transfer from hypervalent iodine species. It covers both the reactions in which an organocatalyst is applied to activate the acceptor, as well as those that exploit the organocatalytic activation of the hypervalent iodine reagent itself.

1 Introduction

2 Organocatalytic Activation of Acceptor

2.1 Amine Catalysis via Enamine and Unsaturated Iminium Formation

2.2 NHC Catalysis via Acyl Anion Equivalent and Enolate Formation

2.3 Chiral Cation Directed Catalysis and Brønsted Base Catalysis via Pairing with Stabilized Enolates

3 Organocatalytic Activation of Hypervalent Iodine Reagent

3.1 Brønsted and Lewis Acid Catalysis

3.2 Lewis Base Catalysis

3.3 Radical Reactions with Organic Promoters and Catalysts

4 Summary and Outlook
Liposarcoma paratesticular gigante
Authors: Cortes-Caballero Carlos , Mogollon-Zehr Margarita Rosa , Campos Silvia Nathalia Vera
Published: November 2018

Introducción Los liposarcomas son lesiones que se originan en el tejido mesodérmico, su localización paratesticular es muy rara. Se divide en 4 subtipos histológicos, siendo el mixoide el más infrecuente. Tiene una recurrencia del 70%, Por lo que su tratamiento inicial debe ser agresivo.

Objetivo resaltar su gran tamaño y que sea considerado como diagnóstico diferencial de masa inguinoescrotal.

Presentación del caso Paciente masculino de 87 años con masa dolorosa inguinoescrotal derecha con diagnóstico de hernia inguinal unilateral, se realiza orquiectomía inguinal derecha. En patología se recibe pieza quirúrgica de 2440 g; al estudio histológico se observa lesión tumoral mesenquimal maligna, rodeado por estroma nodular mixoide prominente. Se diagnostica liposarcoma mixoide de cordón espermático. (Figura 2).

Conclusiones Son neoplasias raras mal diagnosticadas como hernia inguinal, escrotal o lipoma de la médula espermática. Tiene un alto riesgo de metástasis, siendo la orquiectomía inguinal con resección del cordón espermático el manejo quirúrgico ideal.
Accurate prediction of nuclear magnetic resonance shielding constants: An extension of the focal-point analysis method for magnetic parameter calculations (FPA-M) with improved efficiency
Authors: Wang Kangli , Sun Meng , Cui Deng , Shen Tonghao , Wu Anan , Xu Xin
Published: November 2018

Previously, we have proposed a method, FPA-M, for focal-point analysis of magnetic parameter calculations [Sun et al., J. Chem. Phys. 138, 124113 (2013)], where the shielding constants at equilibrium geometries σe are calculated with the second order Møller-Plesset perturbation (MP2) approach, which are extrapolated to the complete basis set (CBS) limit and then augmented by the [σe(CCSD(T)) − σe(MP2)] difference at a valence triple-ζ (VTZ) basis set, where CCSD(T) stands for the coupled cluster singles and doubles model with a perturbative correction for triple excitations. This FPA-M(MP2) method provides satisfactory results to approach to the corresponding CCSD(T)/CBS values for elements of the first two rows in the periodic tables. A series of extensions have been explored here, which replace the MP2/CBS with the Hartree-Fock (HF)/CBS for efficiency. In particular, the [σe(CCSD(T)) − σe(MP2)] VTZ difference is replaced by a step-wise correction from the [σe(CCSD(T)) − σe(MP2)] difference at a valence double-ζ basis set plus the [σe(MP2) − σe(HF)] VTZ difference, leading to a new scheme, denoted here as FPA-M(HF′). A systematical comparison has demonstrated that the FPA-M(HF′) method provides an excellent balance between accuracy and efficiency, which makes routinely accurate calculations of the shielding constants for medium-sized organic molecules and biomolecules feasible.
Study on spatiotemporal dynamic and spectral diagnosis of snowflake pattern in dielectric barrier discharge
Authors: Sun Haoyang , Dong Lifang , Liu Fucheng , Mi Yanlin , Han Rong , Huang Jiayu , Liu Binbin , Hao Fang , Pan Yuyang
Published: November 2018

The snowflake pattern which consists of bright spots and dim lines is investigated in a dielectric barrier discharge system. Visually, dim lines straightforwardly converge to the center of three bright spots. The spatiotemporal dynamics shows that the bright spots are formed by the volume discharges (VDs), and the dim lines are formed by the surface discharges (SDs). The snowflake pattern is the result of VD induced SD and SD transfer surface charges. The emission spectra of the N2 second positive band (C3Πu→B3Πu) and the spectral lines of Ar I (2P2→1S5) of VD and SD are collected and analyzed, respectively. It is found that the ratio values of emission intensity of VD to SD at 696. 5 nm and 380. 4 nm are 4.4 and 1.3, respectively. It indicates that the number of electrons that can excite Ar and N2 to emit the optical spectrum in VD is more than that of SD. A new method of differentiating VD and SD is suggested.
Elastic theory of pseudomorphic monoclinic and rhombohedral heterostructures
Authors: Grundmann Marius
Published: November 2018

We calculate analytically the strain tensor for epitaxial, pseudomorphic heterostructures of arbitrary growth plane for monoclinic and rhombohedral crystals. As numerical examples, we treat heterostructures from sesquioxides, namely, monoclinic (Ga-rich) (Al,Ga)2O3 on β-Ga2O3 and rhombohedral (Al-rich) (Al,Ga)2O3 on α-Al2O3 using realistic material parameters. We predict the strains in laboratory and crystal coordinates and derive properties such as lattice constants and tilt of lattice planes for comparison with X-ray data. Our theory also applies to any higher symmetric structure such as orthorhombic, tetragonal, cubic, and hexagonal heterostructures.
Elastic anomalies across phase transitions of praseodymium to 12 GPa
Authors: Cai Nao , Chen Ting , Qi Xintong , Li Baosheng
Published: November 2018

The elastic properties of praseodymium (Pr) were investigated at pressure up to 12 GPa at room temperature using the ultrasonic interferometry technique. Softening and discontinuities in compressional (P) and shear (S) wave velocities were observed at around 2.5, 6.5, and 10.5 GPa, which are interpreted as indications of the phase transitions from Pr-I (dhcp) to Pr-II (fcc), Pr-II (fcc) to Pr-III (d-fcc), and Pr-III (d-fcc) to Pr-VII (monoclinic or orthorhombic), respectively. Discontinuities in compressibility have been observed across the phase transitions of I-II and II-III of Pr by an analysis of pressure derivatives of the elastic moduli. A comparison with the elastic behaviors of other lanthanide elements (e.g., Ce and La) suggests that the elastic anomalies associated with these phase transitions are likely to be caused by the 6s-5d electron transfer and the softening of acoustic phonon mode facilitated by decreased atomic distances under pressure.
A low-temperature scanning probe microscopy system with molecular beam epitaxy and optical access
Authors: Wu Ze-Bin , Gao Zhao-Yan , Chen Xi-Ya , Xing Yu-Qing , Yang Huan , Li Geng , Ma Ruisong , Wang Aiwei , Yan Jiahao , Shen Chengmin , Du Shixuan , Huan Qing , Gao Hong-Jun
Published: November 2018

A low-temperature ultra-high vacuum scanning probe microscopy (SPM) system with molecular beam epitaxy (MBE) capability and optical access was conceived, built, and tested in our lab. The design of the whole system is discussed here, with special emphasis on some critical parts. The SPM scanner head takes a modified Pan-type design with improved rigidity and compatible configuration to optical access and can accommodate both scanning tunneling microscope (STM) tips and tuning-fork based qPlus sensors. In the system, the scanner head is enclosed by a double-layer cold room under a bath type cryostat. Two piezo-actuated focus-lens stages are mounted on both sides of the cold room to couple light in and out. The optical design ensures the system’s forward compatibility to the development of photo-assisted STM techniques. To test the system’s performance, we conducted STM and spectroscopy studies. The herringbone reconstruction and atomic structure of an Au(111) surface were clearly resolved. The dI/dV spectra of an Au(111) surface were obtained at 5 K. In addition, a periodic 2D tellurium (Te) structure was grown on the Au(111) surface using MBE and the atomic structure is clearly resolved by using STM.
Defect identification based on first-principles calculations for deep level transient spectroscopy
Authors: Wickramaratne Darshana , Dreyer Cyrus E. , Monserrat Bartomeu , Shen Jimmy-Xuan , Lyons John L. , Alkauskas Audrius , Van de Walle Chris G.
Published: November 2018

Deep level transient spectroscopy (DLTS) is used extensively to study defects in semiconductors. We demonstrate that great care should be exercised in interpreting activation energies extracted from DLTS as ionization energies. We show how first-principles calculations of thermodynamic transition levels, temperature effects of ionization energies, and nonradiative capture coefficients can be used to accurately determine actual activation energies that can be directly compared with DLTS. Our analysis is illustrated with hybrid-functional calculations for two important defects in GaN, which have similar thermodynamic transition levels and shows that the activation energy extracted from DLTS includes a capture barrier that is temperature dependent, unique to each defect, and, in some cases, large in comparison to the ionization energy. By calculating quantities that can be directly compared with the experiment, first-principles calculations thus offer powerful leverage in identifying the microscopic origin of defects detected in DLTS.
Flow characterization in converging-diverging microchannels
Authors: Tao Ran , Jin Yakang , Gao Xiang , Li Zhigang
Published: November 2018

Experiments are conducted to investigate fluid flows in converging-diverging microchannels (CDMCs). A new dimensionless number related to channel geometry, Gm, is introduced to combine with the Reynolds number, Re, to characterize the flows. It is found that the new dimensionless number, ReG = Re · Gm, is more appropriate than Re for flow characterization in CDMCs. Flows are laminar for ReG < 40 regardless of the geometry of CDMCs. For laminar flows, the flow resistance model developed in the literature works well. For transitional and turbulent flows, a general scaling law for the flow resistance is developed, which suggests a polynomial dependence of pressure drop on the flow rate. Numerical simulations have also been performed to confirm experimental results.
Face-centered tetragonal (FCT) Fe and Co alloys of Pt as catalysts for the oxygen reduction reaction (ORR): A DFT study
Authors: Sharma Shubham , Zeng Cheng , Peterson Andrew A.
Published: November 2018

Proton exchange membrane fuel cells (PEMFCs) are promising candidates for alternate energy conversion devices owing to their various advantages including high efficiency, reliability, and environmental friendliness. The performance of PEMFCs is fundamentally limited by the sluggish kinetics of the oxygen reduction reaction (ORR) at the cathode. Various studies have addressed myriads of Pt-based alloys as potential catalysts for ORR. However, most of these studies only focus on the cubic-structured Pt-based alloys which require further improvements especially in terms of stability and required loading. In this work, we perform first-principle density functional theory calculations to explore Fe and Co alloys of Pt in a different face centered tetragonal (L10) geometry as potential catalysts for ORR. The work focuses on understanding the reaction mechanism of ORR by both dissociative and associative mechanisms on L10–FePt/Pt(111) and L10–CoPt/Pt(111) surfaces. The binding pattern of each reaction intermediate is studied along with the complete reaction free energy landscape as a function of Pt overlayers. The L10–FePt/Pt(111) and L10–CoPt/Pt(111) surfaces show higher calculated surface activity for ORR as compared to the native fcc Pt(111) surface. The decrease in the required overpotential (η) for the alloys with respect to the unstrained Pt(111) surface is found to be in the range (0.04 V–0.25 V) assuming the dissociative mechanism and (0.02 V–0.10 V) assuming the associative mechanism, where the variation depends on the thickness of Pt overlayers. We further correlate the binding behavior of the reaction intermediates to the applied biaxial strain on the Pt(111) surface with the help of a mechanical eigenforce model. The eigenforce model gives a (semi-) quantitative prediction of the binding energies of the ORR intermediates under applied biaxial strain. The numerical values of the limiting potential (UL) obtained from the eigenforce model are found to be very close to ones obtained from electronic structure calculations (less than 0.1 V difference). The eigenforce model is further used to predict the ideal equi-biaxial strain range required on Pt(111) surfaces for optimum ORR activity.
Electronic transport in degenerate (100) scandium nitride thin films on magnesium oxide substrates
Authors: Cetnar John S. , Reed Amber N. , Badescu Stefan C. , Vangala Shivashankar , Smith Hadley A. , Look David C.
Published: November 2018

Scandium nitride (ScN) is a degenerate n-type semiconductor with very high carrier concentrations, low resistivity, and carrier mobilities comparable to those of transparent conducting oxides such as zinc oxide. Because of its small lattice mismatch to gallium nitride (GaN), <1%, ScN is considered a very promising material for future GaN based electronics. Impurities are the source of the degeneracy. Yet, which specific impurities are the cause has remained in contention. ScN thin films of various thicknesses were grown on magnesium oxide substrates in a (001) orientation using reactive magnetron sputtering across a range of deposition conditions. X-ray diffraction was used to verify crystal orientation. Film thicknesses ranging from 39 to 85 nm were measured using scanning electron microscopy. The electronic transport properties of the films were characterized using Hall-effect measurements at temperatures ranging from 10 to 320 K. At 10 K, the electron concentration varies from 4.4 × 1020 to 1.5 × 1021 cm−3, resistivity from 2.1 × 10−4 to 5.0 × 10−5 Ω·cm, and Hall mobility from 66 to 97 cm2/V·s. Secondary ion mass spectroscopy (SIMS) was used to determine film compositions. Finally, density functional theory (DFT) was used to compute the activation energies for various point defects including nitrogen and scandium vacancies and oxygen and fluorine substituting for nitrogen. For both oxygen and fluorine substitution, the energies were negative, indicating spontaneous formation. Nevertheless, the combined results of the Hall, SIMS, and DFT strongly suggest that oxygen substitution is the primary mechanism behind the high carrier concentration in these samples.
Experimental and theoretical studies of the Xe–OH(A/X) quenching system
Authors: Kłos J. , McCrudden G. , Brouard M. , Perkins T. , Seamons S. A. , Herráez-Aguilar D. , Aoiz F. J.
Published: November 2018

New multi-reference, global ab initio potential energy surfaces (PESs) are reported for the interaction of Xe atoms with OH radicals in their ground X2Π and excited A2Σ+ states, together with the non-adiabatic couplings between them. The 2A′ excited potential features a very deep well at the collinear Xe–OH configuration whose minimum corresponds to the avoided crossing with the 1A′ PES. It is therefore expected that, as with collisions of Kr + OH(A), electronic quenching will play a major role in the dynamics, competing favorably with rotational energy transfer within the 2A′ state. The surfaces and couplings are used in full three-state surface-hopping trajectory calculations, including roto-electronic couplings, to calculate integral cross sections for electronic quenching and collisional removal. Experimental cross sections, measured using Zeeman quantum beat spectroscopy, are also presented here for comparison with these calculations. Unlike similar previous work on the collisions of OH(A) with Kr, the surface-hopping calculations are only able to account qualitatively for the experimentally observed electronic quenching cross sections, with those calculated being around a factor of two smaller than the experimental ones. However, the predicted total depopulation of the initial rovibrational state of OH(A) (quenching plus rotational energy transfer) agrees well with the experimental results. Possible reasons for the discrepancies are discussed in detail.
Production of rotationally cold methyl radicals in pulsed supersonic beams
Authors: Grzesiak Jonas , Vashishta Manish , Djuricanin Pavle , Stienkemeier Frank , Mudrich Marcel , Dulitz Katrin , Momose Takamasa
Published: November 2018

We present a comparison of two technically distinct methods for the generation of rotationally cold, pulsed supersonic beams of methyl radicals (CH3): a plate discharge source operating in the glow regime and a dielectric barrier discharge source. The results imply that the efficiency of both sources is comparable and that molecular beams with similar translational and rotational temperatures are formed. Methane (CH4) proved to be the most suitable radical precursor species.
Perspective: Computational chemistry software and its advancement as illustrated through three grand challenge cases for molecular science
Authors: Krylov Anna , Windus Theresa L. , Barnes Taylor , Marin-Rimoldi Eliseo , Nash Jessica A. , Pritchard Benjamin , Smith Daniel G. A. , Altarawy Doaa , Saxe Paul , Clementi Cecilia , Crawford T. Daniel , Harrison Robert J. , Jha Shantenu , Pande Vijay S. , Head-Gordon Teresa
Published: November 2018

The field of computational molecular sciences (CMSs) has made innumerable contributions to the understanding of the molecular phenomena that underlie and control chemical processes, which is manifested in a large number of community software projects and codes. The CMS community is now poised to take the next transformative steps of better training in modern software design and engineering methods and tools, increasing interoperability through more systematic adoption of agreed upon standards and accepted best-practices, overcoming unnecessary redundancy in software effort along with greater reproducibility, and increasing the deployment of new software onto hardware platforms from in-house clusters to mid-range computing systems through to modern supercomputers. This in turn will have future impact on the software that will be created to address grand challenge science that we illustrate here: the formulation of diverse catalysts, descriptions of long-range charge and excitation transfer, and development of structural ensembles for intrinsically disordered proteins.
Three-dimensional quantum size effects on the growth of Au islands on MoS2
Authors: Kidd T. E. , Weber J. , Holzapfel R. , Doore K. , Stollenwerk A. J.
Published: November 2018

Quantum confinement was found to play a critical role in the formation of Au(111) islands grown on the surface of MoS2. These confinement effects are fully three dimensional, with a strong correlation with the relatively large Fermi wavelength associated with the Au(111) planes. The confinement effects result in preferred heights with a periodicity of nearly 2 nm and persist to much higher temperatures than are typically seen in electronic growth mode systems. These findings indicate the potential to explore electronic growth modes in systems based on metal-layered semiconductor interfaces.
Nanoscale domains in ionic liquids: A statistical mechanics definition for molecular dynamics studies
Authors: Shadrack Jabes B. , Delle Site L.
Published: November 2018

One of the many open questions concerning Ionic Liquids (ILs) is the existence of nanoscale supra-molecular domains which characterize the bulk. The hypothesis of their existence does not meet a general consensus since their definition seems to be based on ad hoc arbitrary criteria rather than on general and solid first principles of physics. In this work, we propose a suitable definition of supra-molecular domains based on first principles of statistical mechanics. Such principles can be realized through the application of a recently developed computational tool which employs adaptive molecular resolution. The method can identify the smallest region of a liquid for which the atomistic details are strictly required, while the exterior plays the role of a generic structureless thermodynamic reservoir. We consider four different imidazolium-based ILs and show that indeed one can quantitatively represent the liquid as a collection of atomistically self-contained nanodroplets embedded in a generic thermodynamic bath. Such nanodroplets express a characteristic length scale for heterogeneity in ILs.
Investigation on the RONS and bactericidal effects induced by He + O2 cold plasma jets: In open air and in an airtight chamber
Authors: Xu Han , Liu Dingxin , Wang Weitao , Liu Zhijie , Guo Li , Rong Mingzhe , Kong Michael G.
Published: November 2018

He + O2 plasma jets in open air and in an airtight chamber are comparatively studied, with respect to their production of gaseous/aqueous reactive species and their antibacterial effects. Under the same discharge power, the plasma jet in open air has higher densities of gaseous reactive species and a higher concentration of aqueous H2O2 but lower concentrations of aqueous OH and O2-. In addition, the increase in the O2 ratio in He in both plasma jets causes a linear decrease in the population of gaseous reactive species, except for O(3p5P) when a small amount of O2 is added to the working gas. The concentrations of aqueous reactive species for OH and H2O2 also drop monotonically with the increase in additive O2, while the aqueous O2- first increases and then decreases. Moreover, it is interesting that the bactericidal inactivation in the airtight chamber condition is much greater than that in the open air condition regardless of the presence or absence of additive O2 in the He plasma jet. The concentration trends of O2- for both the plasma jets are similar to their antibacterial effects, and little antibacterial effect is achieved when a scavenger of O2- is used, indicating that O2- should be a main antibacterial agent. Moreover, it should not be O2- alone to achieve the antibacterial effect, and some reactive nitrogen species such as ONOO- and O2NOO- might also play an important role.
Engineering quantum interference
Authors: Lucci M. , Merlo V. , Ottaviani I. , Cirillo M. , Badoni D. , Campanari V. , Salina G. , Caputo J. G. , Loukitch L.
Published: November 2018

A model for describing the interference and diffraction of wave functions of one-dimensional Josephson array interferometers is presented. The derived expression for critical current modulations accounts for an arbitrary number of square junctions, the variable distance between these, and the variable size of their area. Predictions are tested on real arrays containing up to 20 equally spaced and identical junctions and on arrays shaped with peculiar geometries. A very good agreement with the modulations predicted by the model and the experimental results is obtained for all the tested configurations. It is shown that specific designs of the arrays generate significant differences in their static and dynamical (non-zero voltage) properties. The results demonstrate that the magnetic field dependence of Josephson supercurrents shows how interference and diffraction of macroscopic quantum wavefunctions can be manipulated and controlled.
Letter: Evolution of coherent vortical structures in a shock wave/turbulent boundary-layer interaction flow
Authors: Zhuang Yi , Tan Hui-jun , Li Xin , Guo Yun-jie , Sheng Fa-jia
Published: November 2018

Evolution of coherent vortical structures (CVSs) in shock wave/turbulent boundary-layer interactions (SWBLIs) is a fundamental yet relatively unexplored physical problem. A direct insight into this issue can help understand the SWBLI phenomenon from a more microcosmic perspective and provide new experimental results to the community of high-resolution numerical simulation. Thus, ice-cluster planar laser scattering technique is applied to acquire high spatiotemporal resolution images of the turbulent boundary-layer. Two-dimensional slices (2DS) of CVSs, from which statistical information can be acquired, are extracted by a machine-learning based method. Finally, by comparing features of 2DS-CVSs in the pre-separation zone and the post-reattachment zone, the evolution of CVSs in SWBLI is analyzed.
Training a wild-born marsupial to use microchip-automated devices: the brush-tailed phascogale (Phascogale tapoatafa) as proof of concept
Authors: Edwards M. C. , Hoy J. M. , FitzGibbon S. , Murray P. J.
Published: November 2018

Microchip-automated feeders and doors allow individualised access to supplementary food and shelter during soft-release of wildlife. A wild-caught brush-tailed phascogale was used to test whether a wild animal could be trained to use microchip-automated devices. The phascogale was trained to use each device in less than a month.
Synchrotron infrared microspectroscopy reveals the response of Sphagnum cell wall material to its aqueous chemical environment
Authors: Silvester Ewen , Klein Annaleise R. , Whitworth Kerry L. , Puskar Ljiljana , Tobin Mark J.
Published: November 2018

Environmental contextSphagnum moss is a widespread species in peatlands globally and responsible for a large fraction of carbon storage in these systems. We used synchrotron infrared microspectroscopy to characterise the acid-base properties of Sphagnum moss and the conditions under which calcium uptake can occur (essential for plant tissue integrity). The work allows a chemical model for Sphagnum distribution in the landscape to be proposed.
AbstractSphagnum is one the major moss types responsible for the deposition of organic soils in peatland systems. The cell walls of this moss have a high proportion of carboxylated polysaccharides (polygalacturonic acids), which act as ion exchangers and are likely to be important for the structural integrity of the cell walls. We used synchrotron light source infrared microspectroscopy to characterise the acid-base and calcium complexation properties of the cell walls of Sphagnum cristatum stems, using freshly sectioned tissue confined in a flowing liquid cell with both normal water and D2O media. The Fourier transform infrared spectra of acid and base forms are consistent with those expected for protonated and deprotonated aliphatic carboxylic acids (such as uronic acids). Spectral deconvolution shows that the dominant aliphatic carboxylic groups in this material behave as a monoprotic acid (pKa=4.97–6.04). The cell wall material shows a high affinity for calcium, with a binding constant (K) in the range 103.9–104.7 (1:1 complex). The chemical complexation model developed here allows for the prediction of the chemical environment (e.g. pH, ionic content) under which Ca2+ uptake can occur, and provides an improved understanding for the observed distribution of Sphagnum in the landscape.
A small single-domain protein folds through the same pathway on and off the ribosome
Authors: Guinn Emily J. , Tian Pengfei , Shin Mia , Best Robert B. , Marqusee Susan
Published: November 2018

Significance

All proteins are synthesized by the ribosome and therefore have the opportunity to fold for the first time while they are still attached to it. Although protein folding in vitro has been extensively characterized, we are just beginning to understand how proteins fold on the ribosome, which is essential to understanding protein folding in vivo. Here, we characterize and compare the folding pathway of a single protein domain on the ribosome and in bulk solution. By probing the response of the protein to mechanical force, chemical denaturant, and point mutations, and comparing experimental results to simulations, we show that this single protein domain folds through the same pathway on and off the ribosome.