bluuebunny/crossref_metadata_2025 huggingface dataset:
Densely grafted liquid crystalline copper phthalocyanine side chain polymer: synthesis and characterization
Authors: Heinrich C. David , Tuncel Kostakoğlu Sinem , Thelakkat Mukundan
Published: May 2017

Synthesis and characterization of a liquid crystalline polymer with pendant copper phthalocyanine side chains (PCuPc).
Luminescence properties and energy transfer of YGa1.5Al1.5(BO3)4:Tb3+,Eu3+ as a multi-colour emitting phosphor for WLEDs
Authors: Li Junhao , Zhang Zihan , Li Xiaohui , Xu Yiqin , Ai Yeye , Yan Jing , Shi Jianxin , Wu Mingmei
Published: May 2017

Energy-transfer-based multi-colour emissions in YGa1.5Al1.5(BO3)4:Tb3+,Eu3+ for WLEDs.
Colorimetric sensor arrays for amines based on responsive lanthanide complex entrapment
Authors: Li Peng , Li Zhiqiang , Yao Decui , Li Huanrong
Published: May 2017

Herein a small sensor array generated by encapsulating Eu–Tb binuclear complexes within the cavities of zeolite Y (ZY) can be used as a fingerprint to discriminate 13 amine molecules and amine concentrations in water. Such work offers a new direction for developing sensitive array sensing for multi-analyte systems.
Luminescence of samarium(iii) bis-dithiocarbamate frameworks: codoped lanthanide emitters that cover visible and near-infrared domains
Authors: Wang Shanshan , Xu Jin , Wang Juan , Wang Kai-Yao , Dang Song , Song Shuyan , Liu Dan , Wang Cheng
Published: May 2017

A porous 3D Sm-S-MOF with the white light emission, and especially for near-infrared (NIR) luminescent barcodes obtained from a single material has been explored.
Role of SDF-1α/CXCR4 signaling pathway in clinicopathological features and prognosis of patients with nasopharyngeal carcinoma
Authors: Li Yun-Ling , Li Yu-Fen , Li Hua-Feng , Lv Huai-Qing , Sun De-Zhong
Published: May 2017

The present study aims to explore the role of stromal cell-derived factor-1α (SDF-1α)/stromal cell-derived factor receptor-4 (CXCR4) signaling pathway to the clinicopathological features and prognosis of patients with nasopharyngeal carcinoma (NPC). From January 2009 to December 2010, 102 patients with NPC and 80 patients with chronic nasopharyngitis were enrolled for the study. Immunohistochemical staining, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blotting were employed to determine the expressions of SDF-1α and CXCR4 proteins in NPC tissues and chronic nasopharyngitis tissues. Chi-square test was conducted to analyze the associations of the expressions of SDF-1α and CXCR4 proteins with the clinicopathological features of NPC patients. Spearman rank correlation analysis was used to analyze the correlation between the SDF-1α protein expression and CXCR4 protein expression. The mRNA and protein expressions of SDF-1α and CXCR4 in NPC tissues were significantly higher than those in chronic nasopharyngitis tissues. The expressions of SDF-1α and CXCR4 proteins showed associations with T staging, N staging, tumor node metastasis (TNM) staging, skull base invasion, and cervical lymph node metastasis of NPC patients. Compared with NPC patients showing negative expressions of SDF-1α and CXCR4 proteins, those with positive expressions of SDF-1α and CXCR4 proteins had a significantly shorter survival time. SDF-1α protein, CXCR4 protein, EBV-IgG status, T staging, N staging, TNM staging, skull base invasion, and cervical lymph node metastasis were independent risk factors for the prognosis of NPC. The findings indicated that SDF-1α/CXCR4 signaling pathway might be associated with the clinicopathological features and prognosis of patients with NPC.
Dust in brown dwarfs and extrasolar planets
Authors: Helling Ch. , Tootill D. , Woitke P. , Lee E.
Published: May 2017

Context. Recent observations indicate potentially carbon-rich (C/O > 1) exoplanet atmospheres. Spectral fitting methods for brown dwarfs and exoplanets have invoked the C/O ratio as additional parameter but carbon-rich cloud formation modeling is a challenge for the models applied. The determination of the habitable zone for exoplanets requires the treatment of cloud formation in chemically different regimes.

Aims. We aim to model cloud formation processes for carbon-rich exoplanetary atmospheres. Disk models show that carbon-rich or near-carbon-rich niches may emerge and cool carbon planets may trace these particular stages of planetary evolution.

Methods. We extended our kinetic cloud formation model by including carbon seed formation and the formation of C[s], TiC[s], SiC[s], KCl[s], and MgS[s] by gas-surface reactions. We solved a system of dust moment equations and element conservation for a prescribed Drift-Phoenixatmosphere structure to study how a cloud structure would change with changing initial C/O0 = 0.43...10.0.

Results. The seed formation efficiency is lower in carbon-rich atmospheres than in oxygen-rich gases because carbon is a very effective growth species. The consequence is that fewer particles make up a cloud if C/O0 > 1. The cloud particles are smaller in size than in an oxygen-rich atmosphere. An increasing initial C/O ratio does not revert this trend because a much greater abundance of condensible gas species exists in a carbon-rich environment. Cloud particles are generally made of a mix of materials: carbon dominates if C/O0 > 1 and silicates dominate if C/O0 < 1. A carbon content of 80–90% carbon is reached only in extreme cases where C/O0 = 3.0 or 10.0.

Conclusions. Carbon-rich atmospheres form clouds that are made of particles of height-dependent mixed compositions, sizes and numbers. The remaining gas phase is far less depleted than in an oxygen-rich atmosphere. Typical tracer molecules are HCN and C2H2 in combination with a featureless, smooth continuum due to a carbonaceous cloud cover, unless the cloud particles become crystalline.
2D and 3D fault basis for fuel cell diagnosis by external magnetic field measurements
Authors: Ifrek Lyes , Cauffet Gilles , Chadebec Olivier , Bultel Yann , Rosini Sébastien , Rouveyre Luc
Published: May 2017

An original approach used for the identification of faults in fuel cell stacks is presented. It is based on the 3D reconstruction of the current density from external magnetic field measurements which is an ill-posed magnetostatic linear inverse problem. A suitable and original current density and magnetic field basis are proposed in order to define both local and global faults on a fuel cell stack. The inverse problem is regularized by truncated singular value decomposition (SVD) to ensure the uniqueness of the solution.
Synthesis of (E)-4,5-Dihydro-1H-Pyrazoles via Tandem Intermolecular Addition–Cyclization of N-Propargylic Sulfonylhydrazones
Authors: Chen Yi-Hui , Tang Hai-Tao , Zeng Jia-Hao , Chen Jun-Jia , Zhan Zhuang-Ping
Published: May 2017

A new strategy for the synthesis of (E)-4-benzylidene-4,5-dihydro-1H-pyrazoles through tandem intermolecular addition–intramolecular cyclization of N-propargylic sulfonylhydrazones has been developed. In this study, we firstly report that N-propargylic sulfonylhydrazones react with electrophilic reagents to afford 4-substituted pyrazole derivatives.
Improved Fmoc Solid-Phase Peptide Synthesis of Oxytocin with High Bioactivity
Authors: Sun Pengcheng , Tang Wenli , Huang Yu , Hu Bi-Huang
Published: May 2017

We described here the synthesis of oxytocin by an improved Fmoc solid-phase peptide synthesis (SPPS) method with a Rink-Amide resin as the solid support, HBTU as the coupling reagent, Fmoc-protected amino acids as the building blocks, and piperazine for Fmoc removal as a substitute for the standard reagent piperidine. Unlike previously reported syntheses, the removal of the S-Acm protecting group of Cys and cyclization forming the disulfide bond were carried out by using iodine on the resin with the fully protected peptide chains. Finally, a crude oxytocin with a purity of 92% was obtained by simultaneous cleavage of the peptide chains from the resin and removal of all side-chain protecting groups with trifluoroacetic acid containing the scavengers (yield 85%). The crude peptide was purified by using preparative RP-HPLC to obtain oxytocin (high purity 99.3%) with a bioactivity of 588 IU/mg, the highest reported so far in the literature. This investigation provides a contribution in efforts for the large-scale synthesis of oxytocin in high purity under mild conditions with iodine for on-resin disulfide bond formation and a substitute for the standard Fmoc-deprotecting reagent piperidine, a controlled substance.
Inflammasomes in Liver Fibrosis
Authors: Alegre Fernando , Pelegrin Pablo , Feldstein Ariel
Published: May 2017

Cell death and inflammation are two central elements in the development of liver fibrosis. Inflammasomes are intracellular multiprotein complexes expressed in both hepatocytes and nonparenchymal cells in the liver that are key regulators of inflammation and cell fate. They respond to cellular danger signals by activating caspase 1, releasing the proinflammatory cytokines IL-1β and IL-18, as well as initiating a novel pathway of programmed cell death termed “pyroptosis.” These processes can initiate and perpetuate an abnormal wound-healing response with the principle cellular target being the activation of hepatic stellate cells. From the various inflammasomes, the NLRP3 inflammasome has been increasingly implicated in the pathogenesis of chronic inflammatory liver diseases, including nonalcoholic steatohepatitis, a disease process that is soaring and has evolved as a primary cause of liver fibrosis and need for liver transplantation. In this review, the authors highlight the growing evidence for both indirect and direct effects of inflammasomes in triggering liver fibrosis as well as potential novel targets for antifibrotic therapies.
Update on the Mechanisms of Liver Regeneration
Authors: Preziosi Morgan , Monga Satdarshan
Published: May 2017

Liver possesses many critical functions such as synthesis, detoxification, and metabolism. It continually receives nutrient-rich blood from gut, which incidentally is also toxin-rich. That may be why liver is uniquely bestowed with a capacity to regenerate. A commonly studied procedure to understand the cellular and molecular basis of liver regeneration is that of surgical resection. Removal of two-thirds of the liver in rodents or patients instigates alterations in hepatic homeostasis, which are sensed by the deficient organ to drive the restoration process. Although the exact mechanisms that initiate regeneration are unknown, alterations in hemodynamics and metabolism have been suspected as important effectors. Key signaling pathways are activated that drive cell proliferation in various hepatic cell types through autocrine and paracrine mechanisms. Once the prehepatectomy mass is regained, the process of regeneration is adequately terminated. This review highlights recent discoveries in the cellular and molecular basis of liver regeneration.
Update Dyslipidämien – Kommentar zur aktualisierten ESC/EAS-Leitlinie 2016
Authors: Sinning David , Landmesser Ulf
Published: May 2017

Was ist neu?

Risikostratifizierung Für eine geeignete therapeutische Strategie zur kardiovaskulären Prävention werden in der aktuellen ESC/EAS-Leitlinie 4 Risikokategorien definiert. Risiko-modulierende Faktoren sind u. a. eine atherosklerotische kardiovaskuläre Erkrankung, ein bestehender Diabetes mellitus und ein bereits manifester Endorganschaden.

LDL-C als primäres Therapieziel Das LDL-Cholesterin wird als der primäre therapeutische Zielwert für die kardiovaskuläre Prävention empfohlen. Das HDL-Cholesterin wird in den aktuellen Leitlinien nicht als therapeutischer Zielwert empfohlen. Neben dem Erreichen eines LDL-C-Zielwertes (z. B. < 70 mg/dl für Patienten mit sehr hohem kardiovaskulärem Risiko) wird nun gleichzeitig eine LDL-C-Senkung um mehr als 50 % bei Patienten mit hohem und sehr hohem kardiovaskulärem Risiko als Therapieziel empfohlen, wenn ein gering oder moderat erhöhter LDL-C-Ausgangswert vorliegt.

Lipidmodifizierende Therapie Wenn der jeweilige LDL-C-Zielwert unter alleiniger Statintherapie in maximal verträglicher Dosis nicht erreicht wird, sollte eine zusätzliche Therapie mit Ezetimib erwogen werden. Des Weiteren besteht nunmehr bei Patienten mit sehr hohen LDL-Cholesterinspiegeln trotz einer maximal verträglichen Statin/Ezetimib-Therapie die Möglichkeit der effektiven LDL-C-Reduktion mittels PCSK9-Inhibition.
Stellenwert der ambulanten Geriatrie
Authors: Kraft Johannes
Published: May 2017

Was ist neu

Ambulante Gesundheitsversorgung im Alter Aktuelle Bedarfsplanung und Versorgungsrealität weichen zunehmend auseinander. Geriatrie erfolgt idealerweise als abgestufte Versorgung in einem regionalen Netzwerk.

Hausärztlich-geriatrische Grundversorgung Das Basisassessment ermöglicht die Integration geriatrischer Screening-Diagnostik in den Praxisalltag. Ein vernetztes Konzept haus- und fachärztlicher Versorgung mit einer spezialisierten ambulanten Versorgung hat das Potenzial, stationäre Einweisungen zu vermeiden und die Qualität der ambulanten Versorgung geriatrischer Patienten zu steigern.

KBV-Entwurf „Spezifische geriatrische Versorgung“ Die Kassenärztliche Bundesvereinigung (KBV) hat im ambulanten kassenärztlichen Bereich eine Zwischenstufe zwischen spezialisierter Versorgung durch Geriater an Kliniken und niedergelassenen Kassenärzten skizziert.

Spezialisierte Versorgung nach EBM-Abschnitt 30.13 Seit dem 1.7.2016 können Hausärzte Patienten die Chance auf spezialisierte geriatrische Beratung und Diagnostik eröffnen. Sie wird in Verbindung mit kooperierenden Therapieteams von zugelassenen niedergelassenen Geriatern oder an geriatrischen Institutsambulanzen auf Zuweisung erbracht.

Neue Modelle erweiterter geriatrischer Institutsambulanzen/Ausblick Die kooperative Zusammenarbeit von Hausärzten mit ambulant tätigen Geriatern eröffnet Chancen, präventive, akutmedizinische, rehabilitative und palliative Leistungen regional abgestimmt und bedarfsgerecht weiter zu entwickeln.
Möglichkeiten der Tabakprävention im Strafvollzug – Eine Übersicht aus bisherigen Erfahrungen der Tabakprävention in Gefängnissen und deren Nutzen für den Jugendstrafvollzug
Authors: Richter Simone , Stöver Heino
Published: May 2017

Es liegen nur wenige Erkenntnisse über die Wirksamkeit der Tabakprävention im gesamten Strafvollzug, besonders aber im Jugendstrafvollzug vor. Das Ziel der Arbeit ist es, den aktuellen Forschungsstand von Maßnahmen der Tabakprävention im Strafvollzug zusammen zu tragen, die für Jugendstrafgefangene im Alter von 14–24 Jahren als Orientierung genutzt werden können. Es erfolgte eine systematische Literaturrecherche in den Datenbanken MEDLINE, Embase, the Cochrane Library, PsycINFO und Web of Science sowie per Handsuche. Daraus ergaben sich 17 relevante Studien, die sich größtenteils auf den Erwachsenenvollzug bezogen. Als die hilfreichsten Unterstützungsmethoden im Rauchausstieg wurden Belohnungssysteme und mehr Freizeitangebote identifiziert. Durch kombinierte Maßnahmen, wie Beratungen und pharmakologische Behandlung, konnten vergleichende Abstinenzraten wie in der Allgemeinbevölkerung erreicht werden. Begrenzte Rauchverbote innerhalb des Gefängnisses, mit Ausnahme des Haftraums, erwiesen sich als effektive Methoden des Passivrauchschutzes, die auch von den Jugendstrafgefangenen akzeptiert werden. Schlussfolgernd zeigen die Ergebnisse effektive und durchführbare Methoden der Tabakentwöhnung und des Passivrauchschutzes in Haft. Eine direkte Übertragung der Ergebnisse auf den Jugendstrafvollzug in Deutschland ist jedoch nicht möglich. Für die Implementierung der Tabakprävention im Jugendstrafvollzug sind ein bedürfnisorientiertes und zielgruppenspezifisches Vorgehen und die Einbeziehung aller Betroffenen erforderlich. Durch eine vorausgehende qualitative Forschung können der Bedarf und die Bedürfnisse ermittelt werden.
Forced Retirement from Professional Rugby Union is Associated with Symptoms of Distress
Authors: Brown James , Kerkhoffs Gino , Lambert Mike , Gouttebarge Vincent
Published: May 2017

Rugby has a higher injury burden than other popular sports, such as football. Athletes who are forced to retire as a result of injury are associated with poor mental health. With its high injury burden, professional rugby players might be at risk of mental health conditions associated with injury-related forced retirement. This study aimed to compare mental health between former professional rugby players who were and weren’t forced to retire. A questionnaire including the 4DSQ (distress), GHQ-12 (anxiety/depression), PROMIS short-form (sleep disturbance) and AUDIT-C (alcohol misuse) was completed by retired professional players from Ireland, France and South Africa. The questionnaire asked players whether or not they were forced to retire, as well as the reason for retirement. Players forced to retire were more than twice as likely to report symptoms of distress in comparison to those that retired voluntarily (odds ratio: 2.1, 95% confidence interval: 1.2–3.6, p<0.001). None of the other mental health measures (anxiety/depression, sleep disturbance or alcohol misuse) were associated with forced retirement. In conclusion, rugby players that were forced to retire may require support structures and longitudinal monitoring. Future studies should begin monitoring players during their careers to accurately assess the effect of retirement on mental health.
Immundefizienz im Erwachsenenalter
Authors: Salzer Ulrich , Warnatz Klaus
Published: May 2017

Was ist neu?

Diagnostik primärer Immundefekte Eine frühe und präzise Diagnosestellung primärer Immundefekte ist notwendig. Die AWMF-Leitlinie definiert Warnzeichen und eine Stufendiagnostik, um dieses Ziel zu erreichen.

Variabler Immundefekt (CVID) CVID ist der Sammelbegriff für ein heterogenes Antikörpermangelsyndrom, das durch die zunehmende Anwendung moderner genetischer Diagnostik und bessere gezielte Therapieoptionen eine dramatische Reform mit diagnostischen und therapeutischen Folgen erfährt.

Gata2-Defizienz Heterozygote Mutationen in dem hämatopoetischen Transkriptionsfaktor GATA2 führen zu einem seltenen, klinisch heterogenen Krankheitsbild. Neben Störungen der Hämatopoese ist eine Immundefizienz im Erwachsenenalter die häufigste Manifestation.
Inotrope Substanzen beim infarktbedingten kardiogenen Schock
Authors: Janssens Uwe , Riessen Reimer
Published: May 2017

Was ist neu?

Therapeutisch eingesetzte Katecholamine Inotrop wirksame Katecholamine und Phosphodiesterase-Hemmer werden zur Behandlung des kardiogenen Schocks eingesetzt. Gerade bei der dominierenden Form des infarktbedingten kardiogenen Schocks ist dies aus pathophysiologischer Sicht jedoch mit großen Risiken verbunden und noch nie für diese Indikation in größeren randomisierten Studien validiert worden.

Alternative Levosimendan Aktuelle Leitlinien empfehlen einen vorsichtigen Umgang mit inotropen Substanzen. Adrenalin sollte vermieden werden. Die Gabe des Kalzium-Sensitizers Levosimendan birgt dagegen theoretisch Vorteile. Dies ist aber durch Studiendaten noch nicht ausreichend belegt.

Kardioprotektive und Katecholamin-restriktive Therapie Es werden hochwertige Studien benötigt, die eine „kardioprotektive Therapie“ mit einem sehr restriktiven Einsatz von Katecholaminen und perfusionsbasierten Zielparametern mit einem konventionellen Management des kardiogenen Schocks vergleichen.
Clinical utility of a functional lumen imaging probe in management of dysphagia following head and neck cancer therapies
Authors: Wu Peter , Szczesniak Michal , Maclean Julia , Choo Lennart , Quon Harry , Graham Peter , Zhang Teng , Cook Ian
Published: May 2017

Background and aims Chemoradiotherapy for head and neck cancer (HNC) with/without laryngectomy commonly causes dysphagia. Pharyngoesophageal junction (PEJ) stricturing is an important contributor. We aimed to validate a functional lumen imaging probe (the EndoFLIP system) as a tool for quantitating pretreatment PEJ distensibility and treatment-related changes in HNC survivors with dysphagia and to evaluate the diagnostic accuracy of EndoFLIP-derived distensibility in detecting PEJ strictures.

Methods We studied 34 consecutive HNC survivors with long-term (> 12 months) dysphagia who underwent endoscopic dilation for suspected strictures. Twenty non-dysphagic patients undergoing routine endoscopy served as controls. PEJ distensibility was measured at endoscopy with the EndoFLIP system pre- and post-dilation. PEJ stricture was defined as the presence of a mucosal tear post-dilation.

Results PEJ stricture was confirmed in 22/34 HNC patients (65 %). During distension up to 60 mmHg, the mean EndoFLIP-derived narrowest cross-sectional area (nCSA) in HNC patients with strictures, without strictures, and in controls were 58 mm2 (95 % confidence interval [CI] 22 to 118), 195 mm2 (95 %CI 129 to 334), and 227 mm2 (95 %CI 168 to 316), respectively. A cutoff of 114 mm2 for the nCSA at the PEJ had perfect diagnostic accuracy in detecting strictures (area under the receiver operating characteristic curve = 1). In patients with strictures, a single session of dilation increased the nCSA by 29 mm2 (95 %CI 20 to 37; P < 0.001). In patients with no strictures, dilation caused no change in the nCSA (mean difference 13 mm2 [95 %CI −4 to 30]; P = 0.13).

Conclusions EndoFLIP is a highly accurate technique for the detection of PEJ strictures. EndoFLIP may complement conventional diagnostic tools in the detection of pharyngeal outflow obstruction.
3D controlled electrorotation of conducting tri-axial ellipsoidal nanoparticles
Authors: Weis Goldstein Ben , Miloh Touvia
Published: May 2017

We present a theoretical study of 3D electrorotation of ideally polarizable (metallic) nano∖micro-orthotropic particles that are freely suspended in an unbounded monovalent symmetric electrolyte. The metallic tri-axial ellipsoidal particle is subjected to three independent uniform AC electric fields acting along the three principal axes of the particle. The analysis of the electrokinetic problem is carried under the Poisson-Nernst-Planck approximation and the standard “weak” field assumption. For simplicity, we consider the electric double layer as thin and the Dukhin number to be small. Both nonlinear phenomena of dielectrophoresis induced by the dipole-moment within the particle and the induced-charge electrophoresis caused by the Coulombic force density within the Debye layer in the solute surrounding the conducting particle are analytically analyzed by linearization, constructing approximate expressions for the total dipolophoresis angular particle motion for various geometries. The analytical expressions thus obtained are valid for an arbitrary tri-axial orthotropic (exhibiting three planes of symmetry) particle, excited by an arbitrary ambient three-dimensional AC electric field of constant amplitude. The present study is general in the sense that by choosing different geometric parameters of the ellipsoidal particle, the corresponding nonlinear electrostatic problem governed by the Robin (mixed-type) boundary condition can be reduced to common nano-shapes including spheres, slender rods (needles), prolate and oblate spheroids, as well as flat disks. Furthermore, by controlling the parameters (amplitudes and phases) of the forcing electric field, one can reduce the present general 3D electrokinetic model to the familiar planar electro-rotation (ROT) and electro-orientation (EOR) cases.
Spontaneous stacking of purple membranes during immobilization with physical cross-linked poly(vinyl alcohol) hydrogel with retaining native-like functionality of bacteriorhodopsin
Authors: Yokoyama Yasunori , Tanaka Hikaru , Yano Shunsuke , Takahashi Hiroshi , Kikukawa Takashi , Sonoyama Masashi , Takenaka Koshi
Published: May 2017

We previously discovered the correlation between light-induced chromophore color change of a photo-receptor membrane protein bacteriorhodopsin (bR) and its two-dimensional crystalline state in the membrane. To apply this phenomenon to a novel optical memory device, it is necessary that bR molecules are immobilized as maintaining their structure and functional properties. In this work, a poly(vinyl alcohol) (PVA) hydrogel with physical cross-linkages (hydrogen bonds between PVA chains) that resulted from repeated freezing-and-thawing (FT) cycles was used as an immobilization medium. To investigate the effects of physically cross-linked PVA gelation on the structure and function of bR in purple membranes (PMs), spectroscopic techniques were employed against PM/PVA immobilized samples prepared with different FT cycle numbers. Visible circular dichroism spectroscopy strongly suggested PM stacking during gelation. X-ray diffraction data also indicated the PM stacking as well as its native-like crystalline lattice even after gelation. Time-resolved absorption spectroscopy showed that bR photocycle behaviors in PM/PVA immobilized samples were almost identical to that in suspension. These results suggested that a physically cross-linked PVA hydrogel is appropriate for immobilizing membrane proteins in terms of maintaining their structure and functionality.
Electronic and optical properties of Cu2XSnS4 (X = Be, Mg, Ca, Mn, Fe, and Ni) and the impact of native defect pairs
Authors: Chen Rongzhen , Persson Clas
Published: May 2017

Reducing or controlling cation disorder in Cu2ZnSnS4 is a major challenge, mainly due to low formation energies of the anti-site pair (CuZn− + ZnCu+) and the compensated Cu vacancy (VCu− + ZnCu+). We study the electronic and optical properties of Cu2XSnS4 (CXTS, with X = Be, Mg, Ca, Mn, Fe, and Ni) and the impact of defect pairs, by employing the first-principles method within the density functional theory. The calculations indicate that these compounds can be grown in either the kesterite or stannite tetragonal phase, except Cu2CaSnS4 which seems to be unstable also in its trigonal phase. In the tetragonal phase, all six compounds have rather similar electronic band structures, suitable band-gap energies Eg for photovoltaic applications, as well as good absorption coefficients α(ω). However, the formation of the defect pairs (CuX + XCu) and (VCu + XCu) is an issue for these compounds, especially considering the anti-site pair which has formation energy in the order of ∼0.3 eV. The (CuX + XCu) pair narrows the energy gap by typically ΔEg ≈ 0.1–0.3 eV, but for Cu2NiSnS4, the complex yields localized in-gap states. Due to the low formation energy of (CuX + XCu), we conclude that it is difficult to avoid disordering from the high concentration of anti-site pairs. The defect concentration in Cu2BeSnS4 is however expected to be significantly lower (as much as ∼104 times at typical device operating temperature) compared to the other compounds, which is partly explained by larger relaxation effects in Cu2BeSnS4 as the two anti-site atoms have different sizes. The disadvantage is that the stronger relaxation has a stronger impact on the band-gap narrowing. Therefore, instead of trying to reduce the anti-site pairs, we suggest that one shall try to compensate (CuX + XCu) with (VCu + XCu) or other defects in order to stabilize the gap energy.
Schottky barrier tuning via dopant segregation in NiGeSn-GeSn contacts
Authors: Schulte-Braucks Christian , Hofmann Emily , Glass Stefan , von den Driesch Nils , Mussler Gregor , Breuer Uwe , Hartmann Jean-Michel , Zaumseil Peter , Schröder Thomas , Zhao Qing-Tai , Mantl Siegfried , Buca Dan
Published: May 2017

We present a comprehensive study on the formation and tuning of the Schottky barrier of NiGeSn metallic alloys on Ge1-xSnx semiconductors. First, the Ni metallization of GeSn is investigated for a wide range of Sn contents (x = 0–0.125). Structural analysis reveals the existence of different poly-crystalline NiGeSn and Ni3(GeSn)5 phases depending on the Sn content. Electrical measurements confirm a low NiGeSn sheet resistance of 12 Ω/□ almost independent of the Sn content. We extracted from Schottky barrier height measurements in NiGeSn/GeSn/NiGeSn metal-semiconductor-metal diodes Schottky barriers for the holes below 0.15 eV. They decrease with the Sn content, thereby confirming NiGeSn as an ideal metal alloy for p-type contacts. Dopant segregation for both p- and n-type dopants is investigated as a technique to effectively modify the Schottky barrier of NiGeSn/GeSn contacts. Secondary ion mass spectroscopy is employed to analyze dopant segregation and reveal its dependence on both the Sn content and biaxial layer strain.
Detuning-determined qubit-qubit entanglement mediated by plasmons: An effective model for dissipative systems
Authors: Zhang Fan , Zhao Dongxing , Gu Ying , Chen Hongyi , Hu Xueyuan , Gong Qihuang
Published: May 2017

We theoretically investigate a general scheme for determining quantum entanglement of two detuned quantum dots (QDs) mediated by plasmon nanoparticle for weakly driven dissipative systems. By adiabatically eliminating the field operators, an effective model is proposed to find the underlying mechanism for this determination. Two specific hybrid systems composed of two QDs and a metallic nanoparticle (MNP) are considered. In the QD-MNP-QD system, the concurrence maxima generated by the detunings are several times larger than those in the resonance condition because of the robust superposition between the two separated entangled states. However, in the MNP-QD-QD system, the detunings generally reduce entanglement because the dipole-dipole interaction strongly suppresses the superposition of the entangled states. Moreover, the plateau of large concurrence exists for a broad range of parameters in both cases. The scheme is robust to dissipative systems and paves the way to improve entanglement in quantum information devices at the nanoscale.
Measurement of vector transmission matrix and control of beam focusing through a multiple-scattering medium based on a vector spatial light modulator and two-channel polarization holography
Authors: Xie Yi-Yan , Wang Ben-Yi , Cheng Zhen-Jia , Yue Qing-Yang , Guo Cheng-Shan
Published: May 2017

An experimental system for measuring the complex vector transmission matrix (VTM) of an anisotropic multiple-scattering medium (AMSM) is proposed. In this system, a simple vector spatial light modulator unit composed of a conventional transmittance spatial light modulator and a small-angle birefringent beam splitter is introduced to realize programmable and quantitative control of both the amplitudes and phases of two orthogonal polarization components of the input vector beam point by point. At the same time, a two-channel angular-multiplexing holographic polarization recording geometry is applied to realize the synchronous holographic measurement of the two orthogonal polarization components of the scattered light field. Using this system, we measured the VTM of an AMSM composed of the ZnO scattering layer. At the same time, we also demonstrated that the system can be directly applied to realize focusing a vector beam through the AMSM based on the measured VTM.
Highly compressible fluorescent particles for pressure sensing in liquids
Authors: Cellini F. , Peterson S. D. , Porfiri M.
Published: May 2017

Pressure sensing in liquids is important for engineering applications ranging from industrial processing to naval architecture. Here, we propose a pressure sensor based on highly compressible polydimethylsiloxane foam particles embedding fluorescent Nile Red molecules. The particles display pressure sensitivities as low as 0.0018 kPa–1, which are on the same order of magnitude of sensitivities reported in commercial pressure-sensitive paints for air flows. We envision the application of the proposed sensor in particle image velocimetry toward an improved understanding of flow kinetics in liquids.
Plasma equilibrium inside various cross-section capillary discharges
Authors: Bagdasarov G. , Sasorov P. , Boldarev A. , Olkhovskaya O. , Gasilov V. , Gonsalves A. J. , Barber S. , Bulanov S. S. , Schroeder C. B. , van Tilborg J. , Esarey E. , Leemans W. P. , Levato T. , Margarone D. , Korn G. , Bulanov S. V.
Published: May 2017

Plasma properties inside a hydrogen-filled capillary discharge waveguide were modeled with dissipative magnetohydrodynamic simulations to enable analysis of capillaries of circular and square cross-sections implying that square capillaries can be used to guide circularly symmetric laser beams. When the quasistationary stage of the discharge is reached, the plasma and temperature in the vicinity of the capillary axis have almost the same profile for both the circular and square capillaries. The effect of cross-section on the electron beam focusing properties was studied using the simulation-derived magnetic field map. Particle tracking simulations showed only slight effects on the electron beam symmetry in the horizontal and diagonal directions for square capillary.
Hall thruster microturbulence under conditions of modified electron wall emission
Authors: Tsikata S. , Héron A. , Honoré C.
Published: May 2017

In recent numerical, theoretical, and experimental papers, the short-scale electron cyclotron drift instability (ECDI) has been studied as a possible contributor to the anomalous electron current observed in Hall thrusters. In this work, features of the instability, in the presence of a zero-electron emission material at the thruster exit plane, are analyzed using coherent Thomson scattering. Limiting the electron emission at the exit plane alters the localization of the accelerating electric field and the expected drift velocity profile, which in turn modifies the amplitude and localization of the ECDI. The resulting changes to the standard thruster operation are expected to favor an increased contribution by the ECDI to electron current. Such an operation is associated with a degradation of thruster performance and stability.
Temperature-dependent performance of all-NbN DC-SQUID magnetometers
Authors: Liu Quansheng , Wang Huiwu , Zhang Qiyu , Wang Hai , Peng Wei , Wang Zhen
Published: May 2017

Integrated NbN direct current superconducting quantum interference device (DC-SQUID) magnetometers were developed based on high-quality epitaxial NbN/AlN/NbN Josephson junctions for SQUID applications operating at high temperatures. We report the current–voltage and voltage–flux characteristics and the noise performance of the NbN DC-SQUIDs for temperatures ranging from 4.2 to 9 K. The critical current and voltage swing of the DC-SQUIDs decreased by 15% and 25%, respectively, as the temperature was increased from 4.2 to 9 K. The white flux noise of the DC-SQUID magnetometer at 1 kHz increased from 3.9 μΦ0/Hz1/2 at 4.2 K to 4.8 μΦ0/Hz1/2 at 9 K with 23% increase, corresponding to the magnetic field noise of 6.6 and 8.1 fT/Hz1/2, respectively. The results show that NbN DC-SQUIDs improve the tolerance of the operating temperatures and temperature fluctuations in SQUID applications.
Photo-assisted electron emission from illuminated monolayer graphene
Authors: Upadhyay Kahaly M. , Misra Shikha , Mishra S. K.
Published: May 2017

We establish a formalism to address co-existing and complementing thermionic and photoelectric emission from a monolayer graphene sheet illuminated via monochromatic laser radiation and operating at a finite temperature. Taking into account the two dimensional Fermi-Dirac statistics as is applicable for a graphene sheet, the electron energy redistribution due to thermal agitation via laser irradiation, and Fowler's approach of the electron emission, along with Born's approximation to evaluate the tunneling probability, the expressions for the photoelectric and thermionic emission flux have been derived. The cumulative emission flux is observed to be sensitive to the parametric tuning of the laser and material specifications. Based on the parametric analysis, the photoemission flux is noticed to dominate over its coexisting counterpart thermionic emission flux for smaller values of the material work function, surface temperature, and laser wavelength; the analytical estimates are in reasonably good agreement with the recent experimental observations [Massicotte et al., Nat. Commun. 7, 12174 (2016)]. The results evince the efficient utilization of a graphene layer as a photo-thermionic emitter.
Surface diffusion induced shape evolution of multiple circular voids under high current density
Authors: Wang Yuexing , Yao Yao , Keer Leon M.
Published: May 2017

To understand better the failure mechanism of interconnects under high current density, surface diffusion induced multi-voids shape evolution is investigated. The electric current field is solved analytically for a plate containing two circular voids. Based on the mass diffusion theory, the electromigration induced multi-voids shape evolution is predicted. For the isolated void case, the shape is generally preserved and moves steadily in the conductor. For the multi-voids case, a theoretical model is developed to describe the general behavior of voids shape evolution. It is noted that the steady shape of the initial circular void is broken, and bifurcation could occur due to asymmetry of the current distribution around the voids surface. By considering the multi-voids interaction effect, how the void collapses to a crack, coalesces with each other, or splits into smaller voids is clarified.
Measurement of the impact force of a nonequilibrium atmospheric pressure plasma jet on various substrates
Authors: Li C. , Pei X. , Lu X.
Published: May 2017

The impact force of an atmospheric pressure non-equilibrium plasma jet on different substrates is measured using an electronic balance meter with a resolution of 0.98 μN. The effects of the substrate material, amplitude of the applied voltage amplitude, gas flow rate, and distance between the nozzle and the substrate on the impact force are investigated. It is found that the impact force induced by the charged particles is in the range of several μN to more than one hundred μN. The thrust increases lineally with the increase in the applied voltage and decreases with the increase in the distance between the nozzle and the substrate. On the other hand, the gas flow rate and the substrate of the material have more complicated effects on the thrust. Finally, it is found that the electric field of the plasma plume, when it reaches the substrate, can be estimated from the measured impact force, which is in good agreement with the simulation results.
Competitive excitation and osmotic-pressure-mediated control of lasing modes in cholesteric liquid crystal microshells
Authors: Lin Ya-Li , Gong Ling-Li , Che Kai-Jun , Li Sen-Sen , Chu Cheng-Xu , Cai Zhi-Ping , Yang Chaoyong James , Chen Lu-Jian
Published: May 2017

We examined the end-pumped lasing behaviors of dye doped cholesteric liquid crystal (DDCLC) microshells which were fabricated by glass capillary microfluidics. Several kinds of mode resonances, including distributed feedback, Fabry–Pérot (FP), and whispering gallery (WG) modes, can be robustly constructed in each individual DDCLC microshell by varying the beam diameter, namely, tuning the DDCLC gain area. The FP and WG modes were further confirmed experimentally, and the corresponding lasing mechanisms are clearly revealed from the unique material characteristics of DDCLC and the geometrical structure of the microshell. Additionally, we demonstrated that the osmotic pressure can be used to shrink/expand the microshell, productively tuning the excitation of lasing modes in a controlled manner. We wish our findings can provide a new insight into the design of DDCLC microlasers with tunable optical properties.
Interface matching and intermixing of thin MgO barriers and ferromagnetic layers deposited on GaAs (001)
Authors: Tholapi R. , Karateev I. A. , Roshchin B. S. , Asadchikov V. E. , Slobodskyy T. , Hansen W. , Vasiliev A. L.
Published: May 2017

MgO tunneling barriers are extensively studied as a spin filtering and diffusion barrier for deposition of ferromagnetic layers on GaAs (001) surfaces. The relatively large lattice mismatch of the MgO and GaAs substrate and probable formation of interface states at the metal layer side require a careful barrier design. We present a study of deposition, microstructure, and strain relaxation in MgO barriers deposited on GaAs. The dependence of morphology of MgO layers on their thickness was characterized using a combination of X-Ray Reflectivity and High Resolution Transmission Electron Microscopy. The stress at the MgO/GaAs interface was observed to be released through the formation of misfit dislocations and partially by the formation of mis-oriented domains. The deposited MgO and Fe layers were found to be highly textured irrespective of the thickness of MgO layers. Energy dispersive X-ray microanalysis was used to observe intermixing at the interface of Fe and MgO layers.
Pseudoheterocaryum, a new genus segregated from Heterocaryum (Boraginaceae) on the basis of molecular data
Authors: Saadati Nasim , Khoshsokhan Mozaffar Maryam , Sherafati Mahboubeh , Kazempour Osaloo Shahrokh
Published: May 2017

The phylogeny of Heterocaryum and Suchtelenia was examined using sequence data from the internal transcribed spacer region of the nuclear rDNA (ITS) and plastid trnL intron and trnL–trnF intergenic spacer (trnL–F) regions. Results indicated that Heterocaryum is non-monophyletic because of the inclusion of Suchtelenia calycina (C.A.Mey.) A.DC. Heterocaryum laevigatum (Kar. & Kir.) A.DC. formed a distinct branch sister to S. calycina and remaining Heterocaryum species. Hence, all species of Heterocaryum except H. laevigatum (type species of the genus) are transferred to a new genus, Pseudoheterocaryum. Taxonomic descriptions are presented for Pseudoheterocaryum and Heterocaryum, as well as a diagnostic key to the three genera included in the present study.
Petal epidermal micromorphology in holoparasitic Orobanchaceae and its significance for systematics and pollination ecology
Authors: Piwowarczyk Renata , Kasińska Justyna
Published: May 2017

Flowers of holoparasitic plants have evolved several adaptations for pollination as part of their parasitic strategies. A study of the petal epidermis may be useful to systematics as well as to the knowledge of ecological and co-evolutionary adaptations between the parasites and their pollinators. The present work is a comparative study of the microsculpture of nectar guides and landing platforms in the flowers of holoparasitic species in the family Orobanchaceae. In total, 285 samples of 39 species from 10 holoparasitic genera (Boschniakia C.A.Mey. ex Bong., Boulardia F.W.Schultz, Cistanche Hoffmanns. & Link, Conopholis Wallr., Diphelypaea Nicolson, Epifagus Nutt., Mannagettaea H.Sm., Orobanche L., Phacellanthus Siebold & Zucc. and Phelipanche Pomel) and as an outgroup, of six additional hemiparasitic genera (Castilleja Mutis ex L.f., Euphrasia L., Orthantha (Benth.) A.Kern., Parentucellia Viv., Rhinanthus L., and Striga Lour.) were analysed using both light and scanning electron microscopy. Types of epidermal cells were characterised, and their distribution on the adaxial and abaxial surfaces of the petals determined. The following four major epidermal types were recognised: tabular rugose striate cells (TRS), areolate cells (AS), papillose conical cells (PCS) and lobular striate cells (PLS). Two main types of trichomes were observed, namely glandular and non-glandular. Our results showed that petal micromorphology may be useful to systematics; its influence in relation to the pollinators is discussed.
Third time lucky? Another substantially revised sectional classification for Australasian Plagiochila (Plagiochilaceae: Jungermanniopsida)
Authors: Renner Matt A. M. , Patzak Simon D. F. , Heslewood Margaret M. , Schäfer-Verwimp Alfons , Heinrichs Jochen
Published: May 2017

Molecular phylogeny reconstruction has motivated recircumscription of all families and most genera within the Lophocoleinae, and in Plagiochila, the largest genus of this lineage, has refined the sectional classification as well. Here, we extend this ongoing revision in the first study focusing on species from Australasia, a region to date underrepresented in molecular phylogenetic datasets. We reconstructed a phylogeny containing more than 300 individuals from Australasia and the Pacific, and with this tested sectional circumscriptions within the two largely contradictory classifications recently proposed for Plagiochila. Neither scheme satisfactorily captures relationships among species and all sections prove paraphyletic or polyphyletic, with the exception of those defying these properties by virtue of containing only one species. We propose expanding the circumscription of several sections as the best option for achieving a revised classification representing monophyla that remains stable over the short to medium term, given current knowledge. Broader circumscriptions are proposed for section Denticulatae with section Tayloriae as a new synonym; section Arrectae with section Caducifoliae as a new synonym; a reinstated section Deflexifoliae; and section Plagiochila, to include P. trapezoidea; section Belangerianae to include sections Annotinae, Mitteniae and Strombifoliae as new synonyms; and section Durae with section Colensoae as a new synonym. Section Fragmentissimae is applied to the lineage previously named section Deltoideae nom. inval. or section Hodgsoniae nom. inval., as the Tasmanian P. ratkowskiana and New Zealand P. fragmentissima are the same, and sister to other species in the lineage containing P. deltoidea. Morphological characters supporting these groups are identified, but more importantly the proposed revisions provide a robust framework on which informed re-examination of morphology within this variable and species-rich genus can proceed, and we introduce some encouraging avenues in this area.
Splitting Caldesia in favour of Albidella (Alismataceae)
Authors: Lehtonen Samuli
Published: May 2017

Phylogenetic analyses based on 10 molecular markers unquestionably support a sister relationship between Albidella nymphaeifolia and the Caldesia oligococca species group. The type species of the genus Caldesia is excluded from this monophylum. These results are unsurprising in the light of morphological characteristics, but require three new combinations in Albidella to render both Albidella and Caldesia monophyletic. These new combinations are provided here. Under the new circumscription, Albidella shows a disjunct distribution pattern, with one species in the Caribbean region and three species distributed from tropical Africa and along the margins of the Indian Ocean to Australia.
AP1G mediates vacuolar acidification during synergid-controlled pollen tube reception
Authors: Wang Jia-Gang , Feng Chong , Liu Hai-Hong , Feng Qiang-Nan , Li Sha , Zhang Yan
Published: May 2017

Significance

Double fertilization of angiosperms is preceded by the death of gametophytic cells: Two synergid cells degenerate to create a microenvironment for fertilization, whereas the pollen tube bursts to discharge sperm cells. This process is called pollen tube reception, in which a few synergid surface proteins have been identified, but intracellular activities involved are obscure. We report here that vacuolar acidification, mediated by V-ATPases and adaptor protein 1, might be an important mechanism for synergid degeneration during pollen tube reception. The study provides insights into a cell-death mechanism specifically adopted by the plant phylum.
Microlayer source of oxygenated volatile organic compounds in the summertime marine Arctic boundary layer
Authors: Mungall Emma L. , Abbatt Jonathan P. D. , Wentzell Jeremy J. B. , Lee Alex K. Y. , Thomas Jennie L. , Blais Marjolaine , Gosselin Michel , Miller Lisa A. , Papakyriakou Tim , Willis Megan D. , Liggio John
Published: May 2017

Significance

A biogeochemical connection between the atmosphere and the ocean is demonstrated whereby a marine source of oxygenated volatile organic compounds is identified. Compounds of this type are involved in the formation of secondary organic aerosol, which remains one of the most poorly understood components of Earth’s climate system due in part to the diverse sources of its volatile organic compound precursors. This is especially the case for marine environments, where there are more oxygenated volatile organic compounds than can be accounted for by known sources. Although it was observed in the summertime Arctic, this connection may be widespread and important to our understanding of secondary organic aerosol in other remote marine environments, with implications for our understanding of global climate.