bluuebunny/crossref_metadata_2025 huggingface dataset:
Esthesioneuroblastoma and Olfactory Preservation: Is it Reasonable to Attempt Smell Preservation?
Authors: Gompel Jamie , Janus Jeffrey , Hughes Joshua , Stokken Janalee , Moore Eric , Ryan Tarek , Price Daniel , Link Michael
Published: August 2017

Objective Olfactory preservation after resection of esthesioneuroblastoma (ENB) has been reported, however, the ability to predict tumor involvement of the olfactory system is critical to this surgical strategy. This study aims to answer the question: Can a surgeon predict, based on preoperative imaging, whether there is unilateral involvement of the olfactory system allowing for safe attempt of olfactory preservation?

Methods This is a retrospective review of post-resection ENB meeting inclusion criteria of having bilateral olfactory tracts and bulbs submitted at the time of primary resection for pathologic margins. Five board-certified skull base surgeons blinded to the pathology individually reviewed the preoperative MRI scans to predict degree of tumor involvement.

Results Olfactory bulb involvement occurred in both bulbs in 35% of cases and unilateral in 39% of cases, and there was no involvement in 26% of cases sampled. When comparing physician prediction of involved tracts or bulbs, involvement was appropriate or over-called (i.e., called positive when pathology was in fact negative) in 96% of cases.

Conclusion This study demonstrates unilateral or no pathologic olfactory involvement of the olfactory system in 65% of cases. Our ability to predict this involvement, which may allow for a management strategy that attempts to preserve olfactory function, was accurate at 96%. Therefore, interpretation of imaging and proceeding with smell preservation in ENB appears reasonable in this cohort.

Level of Evidence: Level 2b.
Predicting Postpartum Hemorrhage (PPH) during Cesarean Delivery Using the Leicester PPH Predict Tool: A Retrospective Cohort Study
Authors: Dunkerton Suzanna , Jeve Yadava , Walkinshaw Neil , Breslin Eamonn , Singhal Tanu
Published: August 2017

Objective The aim of the present study was to develop a toolkit combining various risk factors to predict the risk of developing a postpartum hemorrhage (PPH) during a cesarean delivery.

Study Design A retrospective cohort study of 24,230 women who had cesarean delivery between January 2003 and December 2013 at a tertiary care teaching hospital within the United Kingdom serving a multiethnic population. Data were extracted from hospital databases, and risk factors for PPH were identified. Hothorn et al recursive partitioning algorithm was used to infer a conditional decision tree. For each of the identified combinations of risk factors, two probabilities were calculated: the probability of a patient producing ≥1,000 and ≥ 2,000 mL blood loss.

Results The Leicester PPH predict score was then tested on the randomly selected remaining 25% (n = 6,095) of the data for internal validity. Reliability testing showed an intraclass correlation of 0.98 and mean absolute error of 239.8 mL with the actual outcome.

Conclusion The proposed toolkit enables clinicians to predict the risk of postpartum hemorrhage. As a result, preventative measures for postpartum hemorrhage could be undertaken. Further external validation of the current toolkit is required.
Die Erforschung molekularer Aspekte homöopathischer Arzneiwirkungen
Authors: Khuda-Bukhsh Anisur Rahman
Published: August 2017

In der Homöopathie werden Mikrodosen, die nach pharmazeutischer Vorschrift verdünnt wurden, häufig mit großem Nutzen für Patienten eingesetzt, auch wenn es theoretisch höchst unwahrscheinlich ­erscheint, dass in solchen Verdünnungen physikalisch auch nur noch ein einziges Molekül der Originalsubstanz vorhanden ist. Kontrollierte biologische ­Experimente deuten darauf hin, dass homöopathische Hochverdünnungen einen spezifischen Effekt aufweisen.
Transtrapezoidale Luxation: Ein Fallbericht
Authors: Latz David , Gehrmann Sebastian Viktor , Jungbluth Pascal , Grassmann Jan , Schiffner Erik , Windolf Joachim
Published: August 2017

Einleitung Frakturen und Luxationen der distalen Handwurzelreihe sind seltene Verletzungen, die in der Regel Folge schwerer
Distorsions-, Stauchungs- oder Quetschtraumata sind. Insbesondere die transtrapezoidale Luxation ist selten und nur wenige Fallberichte sind
in der Literatur beschrieben.

Fallbericht Im vorliegenden Fall zog sich ein 50-jähriger Patient im Rahmen eines Arbeitsunfalls eine schwere Quetschverletzung der
linken Hand zu, bei der es zu einer transtrapezoidalen Luxation des Os trapezoideum und des Os metakarpale II im
Skaphotrapeziotrapezoidalgelenk nach dorsal kam. Es erfolgte die notfallmäßige Reposition und Kompartmentspaltung sowie die perkutane
Stabilisierung mittels drei K-Drähten. Nach sechs Wochen erfolgten die Materialentfernung und die Einleitung einer intensiven
physiotherapeutischen Behandlung. Nach drei Monaten zeigte sich ein kraftvoller, vollständiger Faustschluß (Stärke 75 %, links: 45 kg,
rechts: 60 kg) und eine zur Gegenseite nur gering verminderte Beweglichkeit (Handgelenkextension/-flexion: links: 30–0-60°, rechts:
40–0-60°, Opposition: vollständig (Kapandji-Index 9/10)).

Schlussfolgerung Die transtrapezoidale Luxation stellt eine Rarität dar. In den beschriebenen Fällen einer dorsalen Luxation des Os
trapezoideum im Skaphotrapeziotrapezoidalgelenk kam es zu einer stets verspäteten Diagnosesicherung nach Tagen oder Wochen. In dem
vorliegenden Fall konnte gezeigt werden, dass eine frühzeitige operative Intervention ein sehr gutes funktionelles Ergebnis ergibt.
Incorporation of Fluorinated Pyridine in the Side Chain of 4-Aminoquinolines: Synthesis, Characterization and Antibacterial Activity
Authors: Ranjbar-Karimi Reza , Poorfreidoni Alireza
Published: August 2017

A series of hybrid of 4-aminoquinoline and fluorinated pyridine derivatives were synthesized and their chemical structure were confirmed by 19F-NMR, 1H-NMR, 13C-NMR and FT-IR. All compounds were tested against one Gram-positive and one Gram-negative bacteria to assess their in vitro antibacterial activity. Compounds 10a, 10b, 11a and 12b showed moderate antibacterial activity against Gram-positive bacterium, Staphylococcus aureus.
10. dggö Jahrestagung – Ahoi in Hamburg
Authors: Bükow Andrea , König Hans-Helmut
Published: August 2017

2018 kommt die Jahrestagung der Deutschen Gesellschaft für Gesundheitsökonomie (dggö) nach Hamburg: Die Jubiläumstagung findet vom 5. bis
6. März 2018 im Hauptgebäude der Universität Hamburg statt. Mit dem Kongressthema „Ökonomie und Medizin im Dialog“ steht die
Interdisziplinarität und damit die Zusammenarbeit der beiden unterschiedlichen Fachrichtungen im Mittelpunkt der Tagung.
Pneumokokken-Konjugatimpfstoffe – Modellierung der Kosteneffektivität zur Säuglingsimpfung
Authors: Bretzke Pascal
Published: August 2017

Kuhlmann A, Graf von der Schulenburg JM. Modeling the cost-effectiveness of infant vaccination with pneumococcal conjugate vaccines in
Germany. Eur J Health Econ 2017; 18: 273–292

Im Jahr 2009 hat die Europäische Arzneimittelagentur zwei weitere Pneumokokken-Impfstoffe für die Impfung von Säuglingen zugelassen. Diese
Studie zielt darauf ab, die Kostenwirksamkeit der universellen Säuglingsimpfung (<2 Jahre alt) mit einem 13-wertigen
Pneumokokken-Konjugatimpfstoff (PCV13) im Vergleich zu einem 10-wertigen Pneumokokken-Konjugatimpfstoff (PCV10) zur Prävention von
Pneumokokken-Erkrankungen zu bewerten.
Genomsequenzierung – Was ist Patienten die personalisierte
Medizin wert?
Authors: Potempa Christoph
Published: August 2017

Marshall DA et al. Estimating Preferences for Complex Health Technologies:
Lessons Learned and Implications for Personalized Medicine. Value Health 2017;
20: 32–39

Die Autoren Marshall et al. untersuchen in ihrer Arbeit die Möglichkeiten zur
Ermittlung von Patientenpräferenzen im Zusammenhang mit komplexen
Gesundheitstechnologien am Beispiel der vollständigen Genomsequenzierung
(WGS) und verweisen neben der Bedeutung ihrer Erkenntnisse auch auf
Herausforderungen im Zusammenhang mit der Evaluierung von vergleichbaren
Technologien aus dem Bereich der personalisierten Medizin.
Bayreuther Alumni-Netzwerk – Homecoming der Bayreuther
Gesundheitsökonomen
Authors: Birkner Arne
Published: August 2017

Zahlreiche Alumni und Studierende besuchten am 7. und 8. Juli das diesjährige
Homecoming der Bayreuther Gesundheitsökonomen an der Universität
Bayreuth.
Saliva versus Plasma Bioequivalence of Valsartan/Hydrochlorothiazide in Humans: Validation of Classes II and IV Drugs of the Salivary Excretion Classification System
Authors: Idkaidek Nasir , Agha Haneen , Arafat Tawfiq
Published: August 2017

Aim The aim of this study is to investigate the robustness of using non-invasive saliva instead of plasma for bioequivalence of valsartan and hydrochlorothiazide (HCT) in humans based on Salivary Excretion Classification System (SECS).

Methods Plasma and resting saliva samples were collected over 24 h after oral administration of single dose 160 mg valsartan and 12.5 mg HCT to 12 healthy male volunteers after 10 h overnight fasting. Plasma and saliva concentrations were determined by validated liquid chromatography-mass spectrometry. WinNonlin program V5.2 was used to determine pharmacokinetic parameters and bioequivalence metrics. Moreover, optimized effective intestinal permeability was estimated using PK-Sim/Mobi program V5.6.

Results and Discussion Valsartan is SECS class IV drug due of low permeability and high protein binding and hence didn’t appear in saliva. However, HCT is SECS class II drug due to low permeability and low protein binding. No significant differences were observed in the pharmacokinetic parameters in both plasma matrix and saliva matrix (P˃0.05). The 90% confidence intervals did not pass in all parameters due to the high intra-subject variability and small sample size used in this study. Saliva to plasma ratios of HCT were low, yet with high correlation coefficient of 0.96–0.98. So saliva can be used as alternative to plasma sample in pharmacokinetic studies and in bioequivalence when adequate sample size is used.
Fabrication and characterization of sputtered Cu2O:N/c-Si heterojunction diode
Authors: Takiguchi Yuki , Takei Yutaro , Nakada Kazuyoshi , Miyajima Shinsuke
Published: August 2017

Nitrogen doped cuprous oxide (Cu2O:N) deposited by reactive sputtering was applied to a crystalline silicon (c-Si) based heterojunction diode. The current density–voltage (J–V) characteristics of the fabricated diode showed rectifying characteristics with a high rectifying ratio of 105 at ±1 V. The capacitance–voltage measurements revealed the existence of a large conduction band offset and a small valence band offset at the Cu2O:N/c-Si interface, which implies that Cu2O:N is a suitable material for a hole selective emitter layer in n-type c-Si based heterojunction solar cells. Detailed analysis of the temperature dependent J–V characteristics showed that the diode current was limited by interface recombination originated from Fermi level pinning at the Cu2O:N/c-Si interface.
Modelling and loss analysis of meso-structured perovskite solar cells
Authors: Xue Hansong , Fu Kunwu , Wong Lydia Helena , Birgersson Erik , Stangl Rolf
Published: August 2017

A mathematical model for meso-structured perovskite solar cells is derived and calibrated towards measured intensity dependent current-voltage characteristics. This steady-state device model describes the transport of free carriers, carrier recombination and optical generation. The optical part considers internal transmission, reflection, and absorption of light, using a transfer matrix approach. The carrier recombination in the form of radiative, Auger and Shockley-Read-Hall mechanisms is accounted for inside the perovskite capping layer, as well as interfacial recombination between the perovskite and electron/hole-transporting layers. After calibration by best-fitting the unknown parameters towards intensity dependent current-voltage measurements of an in-house fabricated meso-structured perovskite solar cell, we identify the dominant recombination mechanisms and their locations inside the cell. A subsequent loss analysis indicates that, in our fabricated solar cell, the interfacial recombination between the perovskite/mesoporous titanium dioxide within the mesoporous absorber layer constitutes the main loss channel. This interfacial recombination accounts for up to 46% of all recombination losses at maximum power, thereby exceeding the recombination inside the perovskite capping layer with 31% loss. Furthermore, the thickness of the perovskite capping layer and the mesoporous layer is varied by means of simulation between 50 and 500 nm, in order to predict the optimum device geometry for the calibrated recombination parameters.
Antiferromagnetic anisotropy determination by spin Hall magnetoresistance
Authors: Wang Hua , Hou Dazhi , Qiu Zhiyong , Kikkawa Takashi , Saitoh Eiji , Jin Xiaofeng
Published: August 2017

An electric method for measuring magnetic anisotropy in antiferromagnetic insulators (AFIs) is proposed. When a metallic film with strong spin-orbit interactions, e.g., platinum (Pt), is deposited on an AFI, its resistance should be affected by the direction of the AFI Néel vector due to the spin Hall magnetoresistance (SMR). Accordingly, the direction of the AFI Néel vector, which is affected by both the external magnetic field and the magnetic anisotropy, is reflected in resistance of Pt. The magnetic field angle dependence of the resistance of Pt on AFI is calculated by considering the SMR, which indicates that the antiferromagnetic anisotropy can be obtained experimentally by monitoring the Pt resistance in strong magnetic fields. Calculations are performed for realistic systems such as Pt/Cr2O3, Pt/NiO, and Pt/CoO.
Extension of the SIESTA MHD equilibrium code to free-plasma-boundary problems
Authors: Peraza-Rodriguez H. , Reynolds-Barredo J. M. , Sanchez R. , Geiger J. , Tribaldos V. , Hirshman S. P. , Cianciosa M.
Published: August 2017

SIESTA [Hirshman et al., Phys. Plasmas 18, 062504 (2011)] is a recently developed MHD equilibrium code designed to perform fast and accurate calculations of ideal MHD equilibria for three-dimensional magnetic configurations. Since SIESTA does not assume closed magnetic surfaces, the solution can exhibit magnetic islands and stochastic regions. In its original implementation SIESTA addressed only fixed-boundary problems. That is, the shape of the plasma edge, assumed to be a magnetic surface, was kept fixed as the solution iteratively converges to equilibrium. This condition somewhat restricts the possible applications of SIESTA. In this paper, we discuss an extension that will enable SIESTA to address free-plasma-boundary problems, opening up the possibility of investigating problems in which the plasma boundary is perturbed either externally or internally. As an illustration, SIESTA is applied to a configuration of the W7-X stellarator.
Plasmonic properties of implanted Ag nanoparticles in SiO2 thin layer by spectroscopic ellipsometry
Authors: Battie Yann , En Naciri Aotmane , Chaoui Nouari , Le Gall Yann , Muller Dominique , Carrada Marzia , Mathiot Daniel
Published: August 2017

We report an uncommon study of the insertion of distributions of both volume fraction and depolarization factors in the modeling of the plasmonic properties of implanted Ag nanoparticles (Ag-NPs) in a SiO2 layer when using spectroscopic ellipsometry (SE) characterization. The Ag-NPs were embedded in the SiO2 matrix by Ag+ ion implantation at various doses of 0.5 × 1016, 1 × 1016, 2 × 1016, and 5 × 1016 ions cm−2. The formation of the Ag-NPs in a host matrix of SiO2 was controlled by transmission electron microscopy (TEM). The Ag-NPs are self-organized in the layer, and their mean radius ranges between 2 and 20 nm. The optical properties of layers were extracted by modeling the SE parameters by taking into account the depth profile concentration of Ag-NPs. The mixture of SiO2 and Ag-NP inclusions was modeled as an effective medium according to the shape distributed effective medium theory (SDEMT). In addition to the optical responses, it is shown that this model enables the explanation of the impact of NP shape distribution on the plasmon band and provides precious information about the NP shape characteristics. A good agreement was obtained between ellipsometry and TEM results. The distribution of the volume fraction in the film was found to lead to a gradient of effective dielectric function which was determined by the SDEMT model. The effective dielectric function reveals distinct Ag plasmon resonance varying as the Ag+ ions dose is varied. The real part of the dielectric function shows a significant variation around the plasmon resonance in accordance with the Kramers-Kronig equations. All determined optical parameters by SDEMT are provided and discussed. We highlight that SE combined with SDEMT calculations can be considered as a reliable tool for the determination of the NP shape and volume fraction distributions without the need of TEM.
Enhanced toroidal flow stabilization of edge localized modes with increased plasma density
Authors: Cheng Shikui , Zhu Ping , Banerjee Debabrata
Published: August 2017

Toroidal flow alone is generally thought to have an important influence on tokamak edge pedestal stability, even though theoretical analysis often predicts merely a weak stabilizing effect of toroidal flow on the edge localized modes (ELMs) in experimental parameter regimes. For the first time, we find from two-fluid MHD calculations that such a stabilization, however, can be significantly enhanced by increasing the edge plasma density. Our finding resolves a long-standing mystery whether or how toroidal rotation can indeed have an effective influence on ELMs, and explains why the ELM mitigation and suppression by toroidal rotation are more favorably achieved in higher collisionality regime in recent experiments. The finding suggests a new control scheme on modulating toroidal flow stabilization of ELMs with plasma density, along with a new additional constraint on the optimal level of plasma density for the desired edge plasma conditions.
Space charge effects on the dielectric response of polymer nanocomposites
Authors: Shen Zhong-Hui , Wang Jian-Jun , Zhang Xin , Lin Yuanhua , Nan Ce-Wen , Chen Long-Qing , Shen Yang
Published: August 2017

Adding high-κ ceramic nanoparticles into polymers is a general strategy to improve the performances in energy storage. Classic effective medium theories may fail to predict the effective permittivity in polymer nanocomposites wherein the space charge effects are important. In this work, a computational model is developed to understand the space charge effects on the frequency-dependent dielectric properties including the real permittivity and the loss for polymer nanocomposites with both randomly distributed and aggregated nanoparticle fillers. It is found that the real permittivity of the SrTiO3/polyethylene (12% SrTiO3 in volume fraction) nanocomposite can be increased to as high as 60 when there is nanoparticle aggregation and the ion concentration in the bulk polymer is around 1016 cm–3. This model can be employed to quantitatively predict the frequency-dependent dielectric properties for polymer nanocomposites with arbitrary microstructures.
Enhancing the barrier height in oxide Schottky junctions using interface dipoles
Authors: Tachikawa Takashi , Hwang Harold Y. , Hikita Yasuyuki
Published: August 2017

We demonstrate a 0.37 eV increase in the n-type Schottky barrier height at the Pt/TiO2-terminated SrTiO3 (001) interface by insertion of an ultrathin insulator AgTaO3. While a conventional metal-insulator-semiconductor model predicts a reduction in the barrier height with insulator thickness, the observed increase originates from the two polar surface layers, (AgO)– and (TaO2)+ in AgTaO3 (001), forming an electrostatic dipole directed towards the metal, increasing the barrier height. Based on directly measured optical and dielectric properties of high quality AgTaO3 thin films, we determine the interface energy band diagram including the interface dipole. The capability to exploit the strong ionic charges of oxide surfaces to manipulate interface band alignments beyond bulk values greatly expands the design strategies for tailoring functional oxide interfaces. Up to now, the use of an ultrathin LaAlO3 layer could only decrease the barrier height, but now bidirectional control is possible.
Operator-sum models of quantum decoherence in molecular quantum-dot cellular automata
Authors: Ramsey Jackson S. , Blair Enrique P.
Published: August 2017

Quantum-dot cellular automata is a paradigm for classical computing which departs from the transistor paradigm and provides a system in which quantum phenomena may be studied. Here, the elementary computing device is a cell, a structure having multiple quantum dots and a few mobile charges. A specific operator-sum representation is developed for an exactly modeled double-dot, molecular cell within an environment of N similar neighboring molecules. While an operator-sum representation is not unique, a specific model can be determined by selecting a particular environmental basis. We select the environment's computational basis and calculate the specific and full set of 2N Kraus operators, which match exactly previous models of quantum decoherence in this system. Finally, the timescale for environmental interaction is characterized, enabling the reduction of the large set of Kraus operators to an approximate pair of Kraus operators, exact in the limit of large N.
Silicon homo-heterojunction solar cells: A promising candidate to realize high performance more stably
Authors: Tan Miao , Zhong Sihua , Wang Wenjie , Shen Wenzhong
Published: August 2017

We have investigated the influences of diverse physical parameters on the performances of a silicon homo-heterojunction (H-H) solar cell, which encompasses both homojunction and heterojunction, together with their underlying mechanisms by the aid of AFORS-HET simulation. It is found that the performances of H-H solar cell are less sensitive to (i) the work function of the transparent conductive oxide layer, (ii) the interfacial density of states at the front hydrogenated amorphous silicon/crystalline silicon (a-Si:H/c-Si) interface, (iii) the peak dangling bond defect densities within the p-type a-Si:H (p-a-Si:H) layer, and (iv) the doping concentration of the p-a-Si:H layer, when compared to that of the conventional heterojunction with intrinsic thin layer (HIT) counterparts. These advantages are due to the fact that the interfacial recombination and the recombination within the a-Si:H region are less affected by all the above parameters, which fundamentally benefit from the field-effect passivation of the homojunction. Therefore, the design of H-H structure can provide an opportunity to produce high-efficiency solar cells more stably.
Tunable Fano resonance in mutually coupled micro-ring resonators
Authors: Xiao Huifu , Wu Xiaosuo , Liu Zilong , Zhao Guolin , Guo Xiaonan , Meng Yinghao , Deng Lin , Chen Wenping , Tian Yonghui , Yang Jianhong
Published: August 2017

We simulate and experimentally observe a tunable Fano resonance in a mutual coupling micro-ring resonator (MRR) system which is comprised of two cascaded micro-ring resonators. The scattering matrix model is employed to analyze the modulating characterization of the Fano resonance by changing the effective refractive index of MRRs, and the simulation results indicate that the Fano resonance is the sharpest when two MRRs' resonances are coincident. The Fano resonance device is fabricated on a silicon-on-insulator substrate using the standard complementary metal-oxide-semiconductor (CMOS) fabrication process. The experimental results show that the spectrum of the Fano resonance can be periodically tuned and flipped by applying forward-bias voltages to integrated micro-heaters above the MRRs. The proposed device has unique merits such as compact size, simple structure, CMOS compatible fabrication process, and large-scale integration, which is a promising candidate for high-sensitivity biochemical sensing and low power optical switching/modulating in future.
Formation of nitrogen oxides from atmospheric electrodeless microwave plasmas in nitrogen–oxygen mixtures
Authors: Lee Jungwun , Sun Hojoong , Im Seong-kyun , Soo Bak Moon
Published: August 2017

Electrodeless microwave plasmas were produced in nitrogen–oxygen mixtures at atmospheric pressure to investigate the formation of nitrogen oxides (NOx) from the plasma. The oxygen content in the mixtures is varied in the range of 1%–3%, and the total flowrate is varied in the range of 25–45 slpm while the microwave power is fixed at 2 kW. The rotational and vibrational temperatures of the plasma are measured based on plasma optical emission spectroscopy, and the amount of NOx is measured using a NOx analyzer far downstream from the plasma. The temperatures at the plasma region reach ∼6700 K, and little difference is observed between the rotational and vibrational temperatures as a result of fast vibrational–translational relaxation. Moreover, these temperatures are found to be independent of the flowrate. As the flowrate decreases and the oxygen content in the mixture increases, the level of NOx is increased from 1612 ppm to 9380 ppm. For detailed investigation, plasma kinetic simulations considering trans-rotational, vibrational, and electron temperatures separately are developed and conducted for the plasma region. The level of NOx from the kinetic simulations is found to be considerably smaller than that measured. As the equilibrium mole fraction of NOx is the highest at a temperature of 3120 ± 100 K, with the variation attributable to the composition of species, significant production of NOx is expected to occur at the post-plasma region when the plasma stream is quenched by mixing with the surrounding flow.
Electrical dynamic modulation of THz radiation based on superconducting metamaterials
Authors: Li Chun , Wu Jingbo , Jiang Shoulu , Su Runfeng , Zhang Caihong , Jiang Chengtao , Zhou Gaochao , Jin Biaobing , Kang Lin , Xu Weiwei , Chen Jian , Wu Peiheng
Published: August 2017

We demonstrate an electrically tunable superconducting metamaterial capable of modulating terahertz waves dynamically. The device is based on electromagnetically induced transparency-like metamaterials, and the maximum modulation depth reaches 79.8% in the transmission window. Controlled by an electrical sinusoidal signal, such a device could achieve a modulation speed of approximately 1 MHz. The superior property and simplicity of design make this device promising for the development of high performance THz systems.
Critical angle for interfacial phonon scattering: Results from ab initio lattice dynamics calculations
Authors: Alkurdi A. , Pailhès S. , Merabia S.
Published: August 2017

Thermal boundary resistance is a critical quantity that controls heat transfer at the nanoscale, which is primarily related to interfacial phonon scattering. Here, we combine lattice dynamics calculations and inputs from first principles ab initio simulations to predict phonon transmission at the Si/Ge interface as a function of both the phonon frequency and the phonon wavevector. This technique allows us to determine the overall thermal transmission coefficient as a function of the phonon scattering direction and frequency. Our results show that the thermal energy transmission is highly anisotropic, while thermal energy reflection is almost isotropic. In addition, we found the existence of a global critical angle of transmission beyond which almost no thermal energy is transmitted. This critical angle around 50° is found to be almost independent of the interaction range between Si and Ge, the interfacial bonding strength, and the temperature above 30 K. We interpret these results by carrying out a spectral and angular analysis of the phonon transmission coefficient and differential thermal boundary conductance.
Porous Si as a substrate for the monolithic integration of RF and millimeter-wave passive devices (transmission lines, inductors, filters, and antennas): Current state-of-art and perspectives
Authors: Sarafis Panagiotis , Nassiopoulou Androula G.
Published: August 2017

The increasing need for miniaturization, reliability, and cost efficiency in modern telecommunications has boosted the idea of system-on-chip integration, incorporating the RF front-end circuitry and the passive elements such as RF transmission lines, inductors, antennas, and filters. However, the performance of the passive elements of these circuits is highly degraded when integrated on standard CMOS Si, due to its low resistivity. Porous silicon (PSi) has emerged as a promising local substrate material for the on-chip monolithic integration of high performance passive RF and mm-wave devices, because it combines high resistivity and low permittivity along with CMOS compatibility. This review paper aims at summarizing the obtained results so far in the above area, including transmission lines, inductors, filters, and miniaturized antennas, monolithically integrated on porous Si in a CMOS-compatible environment. In this respect, we first present the requirements for a low-loss, CMOS-compatible RF substrates and we then argue on how PSi fulfills the set requirements. Then, we present the methods used so far to extract the dielectric properties of PSi, which are necessary inputs for designing RF devices. The performance of different passive RF devices such as coplanar waveguides, inductors, filters, and antennas on the local porous Si substrate is then reviewed and compared with the performance of other state-of-the-art RF passive devices based on different technologies. Finally, we discuss the progress made so far towards the industrialization of PSi local RF substrate technology and the challenges that are currently faced towards this objective.
Quantum mechanics of a photon
Authors: Babaei Hassan , Mostafazadeh Ali
Published: August 2017

A first-quantized free photon is a complex massless vector field A=(Aμ) whose field strength satisfies Maxwell’s equations in vacuum. We construct the Hilbert space H of the photon by endowing the vector space of the fields A in the temporal-Coulomb gauge with a positive-definite and relativistically invariant inner product. We give an explicit expression for this inner product, identify the Hamiltonian for the photon with the generator of time translations in H, determine the operators representing the momentum and the helicity of the photon, and introduce a chirality operator whose eigenfunctions correspond to fields having a definite sign of energy. We also construct a position operator for the photon whose components commute with each other and with the chirality and helicity operators. This allows for the construction of the localized states of the photon with a definite sign of energy and helicity. We derive an explicit formula for the latter and compute the corresponding electric and magnetic fields. These turn out to diverge not just at the point where the photon is localized but on a plane containing this point. We identify the axis normal to this plane with an associated symmetry axis and show that each choice of this axis specifies a particular position operator, a corresponding position basis, and a position representation of the quantum mechanics of a photon. In particular, we examine the position wave functions determined by such a position basis, elucidate their relationship with the Riemann-Silberstein and Landau-Peierls wave functions, and give an explicit formula for the probability density of the spatial localization of the photon.
Experimental phase synchronization detection in non-phase coherent chaotic systems by using the discrete complex wavelet approach
Authors: Ferreira Maria Teodora , Follmann Rosangela , Domingues Margarete O. , Macau Elbert E. N. , Kiss István Z.
Published: August 2017

Phase synchronization may emerge from mutually interacting non-linear oscillators, even under weak coupling, when phase differences are bounded, while amplitudes remain uncorrelated. However, the detection of this phenomenon can be a challenging problem to tackle. In this work, we apply the Discrete Complex Wavelet Approach (DCWA) for phase assignment, considering signals from coupled chaotic systems and experimental data. The DCWA is based on the Dual-Tree Complex Wavelet Transform (DT–CWT), which is a discrete transformation. Due to its multi-scale properties in the context of phase characterization, it is possible to obtain very good results from scalar time series, even with non-phase-coherent chaotic systems without state space reconstruction or pre-processing. The method correctly predicts the phase synchronization for a chemical experiment with three locally coupled, non-phase-coherent chaotic processes. The impact of different time-scales is demonstrated on the synchronization process that outlines the advantages of DCWA for analysis of experimental data.
The three-body problem and equivariant Riemannian geometry
Authors: Alvarez-Ramírez M. , García A. , Meléndez J. , Reyes-Victoria J. G.
Published: August 2017

We study the planar three-body problem with 1/r2 potential using the Jacobi-Maupertuis metric, making appropriate reductions by Riemannian submersions. We give a different proof of the Gaussian curvature’s sign and the completeness of the space reported by Montgomery [Ergodic Theory Dyn. Syst. 25, 921–947 (2005)]. Moreover, we characterize the geodesics contained in great circles.
Delay of a microwave pulse in a photonic crystal
Authors: Babitski V. S. , Baryshevsky V. G. , Gurinovich A. A. , Gurnevich E. A. , Molchanov P. V. , Simonchik L. V. , Usachonak M. S. , Zuyeuski R. F.
Published: August 2017

Propagation of a nanosecond microwave pulse through a photonic crystal placed into an X-band waveguide is investigated. The nanosecond pulse is produced via shortening of the microsecond microwave pulse by the plasma electromagnetic band gap structure, which is formed in the waveguide by microwave breakdown ignited discharges inside three neon-filled glass tubes. Measured delay time for nanosecond microwave pulse propagation through the photonic crystal is about 23 ns that is in good agreement with the value obtained by numerical simulation. This time delay value corresponds to the group velocity of microwave pulses in the photonic crystal vgr ≈ 0.11c, where c is the speed of light in vacuum.
On the recombination centers of iron-gallium pairs in Ga-doped silicon
Authors: Nærland Tine Uberg , Bernardini Simone , Haug Halvard , Grini Sigbjørn , Vines Lasse , Stoddard Nathan , Bertoni Mariana
Published: August 2017

Gallium (Ga) doped silicon (Si) is becoming a relevant player in solar cell manufacturing thanks to its demonstrated low light-induced degradation, yet little is known about Ga-related recombination centers. In this paper, we study iron (Fe)-related recombination centers in as-grown, high quality, directionally solidified, monocrystalline Ga-doped Si. While no defect states could be detected by deep level transient spectroscopy, lifetime spectroscopy analysis shows that the minority carrier lifetime in as-grown wafers is dominated by low levels of FeGa related defect complexes. FeGa pairs have earlier been shown to occur in two different structural configurations. Herein, we show that in terms of recombination strength, the orthorhombic pair-configuration is dominant over the trigonal pair-configuration for FeGa. Furthermore, the defect energy level in the band gap for the orthorhombic defect center is determined to be EV + 0.09 eV, and the capture cross-section ratio of the same defect center is determined to be 220.
Significant color space blue-shift of green OLED emitter with sustaining lifetime and substantial efficiency enhancement
Authors: Li Jung-Yu , Chen Shih-Pu , Siao Huei-Jhen , Wu Jin-Han , Chen Guan-Yu , Chen Cheng-Chang , Ho Shu-Yi , Lin Yi-Ping , Hsu Hong-Hui , Lin Jin-Sheng , Jeng Ming-Shan , Chen Nai-Chuan , Zeng Hui-Kai , Juang Jenh-Yih
Published: August 2017

In this study, we demonstrate that by embedding a plasmonic coupling metal layer beneath the active layer of an organic light-emitting diode, the resultant device is capable of inducing significant blue shifts in CIE color space coordinates of emitting light from the green emitting material without compromising the lifetime of the parent material. The implemented device consists of multilayers of organic emitting materials sandwiched by two thin metal layers to form a metal-dielectric-metal (MDM) cavity-like structure. The original green emission with CIE coordinates of (0.22, 0.56) was significantly color space blue-shifted to CIE coordinates of (0.10, 0.53). The MDM device exhibits an efficiency of 62 cd/A at a luminance of 1000 cd/m2, which represents a two-fold enhancement of current efficiency. Moreover, the spectral peak intensity is 4.3 times higher than that in a conventional device, which is much higher than that expected for an optical microcavity model, suggesting that the Purcell effect resulting from the coupling of surface plasmon waves may contribute to the extra enhancement of emission intensity.
Synthesis and characterisation of nanostructured Al–Al3V and Al–(Al3V–Al2O3) composites by powder metallurgy
Authors: Anvari S. Z. , Karimzadeh F. , Enayati M. H.
Published: August 2017

In this study, the formation and characterisation of Aluminium (Al)-based composites by mechanical alloying and hot extrusion were investigated. Initially, the vanadium trialuminide (Al3V) particles with nanosized structure were successfully produced by mechanical alloying and heat treatment. Al3V–Al2O3 reinforcement was synthesised by mechanochemical reduction during milling of V2O5 and Al powder mixture. In order to produce composite powders, reinforcement powders were added to pure Al powders and milled for 5 h. The composite powders were consolidated in an extrusion process. The results showed that nanostructured Al-10 wt-% Al3V and Al-10 wt-% (Al3V–Al2O3) composites have tensile strengths of 209 and 226 MPa, respectively, at room temperature. In addition, mechanical properties did not drop drastically at temperatures of up to 300°C.
Interfacial microstructure and strengthening mechanism in Ti–6Al–4V reinforced Al-7075 alloy
Authors: Hu Jianian , Luo Guoqiang , Zhang Jian , Wu Chuandong , Wu Jialu , Shen Qiang , Zhang Lianmeng
Published: August 2017

In the present study, an Al-7075 alloy reinforced with 15 wt-% TC4 (Ti–6Al–4V) was synthesised by hot pressing. The results of transmission electron microscopy suggest that a well-bonded multilayer interface was created, and that the multilayer has the ability to limit crack initiation at the interface. Sintering at 913 K for 0.5 h proved to be the most effective procedure for limiting the sources of cracking inside the multilayer interface, resulting in an enhanced tensile strength and a compressive strength for the composite of 454 and 873 MPa, respectively. The desired multilayer structure and the strengthening mechanism are discussed in detail. This structure provides guidance for the development of new methods for fabricating composites with excellent mechanical properties.
Effects of intense cooling on microstructure and properties of friction-stir-welded Ti–6Al–4V alloy
Authors: Liu Zhenlei , Wang Yue , Ji Shude , Li Zhengwei
Published: August 2017

Friction stir welding (FSW) was used to join Ti–6Al–4V alloy in air and under intense cooling conditions. The results show that the application of liquid nitrogen is beneficial in decreasing the peak temperature and in reducing the extent of the high-temperature region during welding, leading to a smaller stir zone (SZ). Intense cooling can lead to refined and homogeneous grains in the SZ, resulting in increased microhardness. The FSW joint produced with intense cooling had a tensile strength of 1020 MPa, which is nearly equivalent to that of the base material and is up to 2.6% higher than for the air-cooled joint. The fractographs for both types of joint were characterised by dimples, indicating that the fractures were ductile.
An improved constitutive model for high-temperature flow behaviour of the Fe–Mn–Al duplex steel
Authors: Xu Lixiong , Wu Huibin , Xie Baosheng
Published: August 2017

The high-temperature flow curves of the Fe–Mn–Al duplex steel showed an uncommon yield-like behaviour and an abnormal dynamic recrystallisation behaviour that occurred at low temperatures rather than high temperatures. The interaction of strain partitioning and unsynchronised softening behaviour in δ-ferrite and austenite caused this peculiar flow behaviour. By discussing the stress exponent and apparent activation energy, respectively, at low and high temperatures, a modified hyperbolic sine function was developed to predict the characteristic stresses. By simplifying the material constant θ and compensating the microstructural evolution in the exponential saturation work-hardening law, an improved constitutive model was developed to predict the transient stress. The comparison between the experimental and calculated values confirmed a high prediction accuracy of this improved model.
Dendritic cell and antigen dispersal landscapes regulate T cell immunity
Authors: Gerner Michael Y. , Casey Kerry A. , Kastenmuller Wolfgang , Germain Ronald N.
Published: August 2017

Dendritic cell (DC) subsets with biased capacity for CD4+ and CD8+ T cell activation are asymmetrically distributed in lymph nodes (LNs), but how this affects adaptive responses has not been extensively studied. Here we used quantitative imaging to examine the relationships among antigen dispersal, DC positioning, and T cell activation after protein immunization. Antigens rapidly drained into LNs and formed gradients extending from the lymphatic sinuses, with reduced abundance in the deep LN paracortex. Differential localization of DCs specialized for major histocompatibility complex I (MHC I) and MHC II presentation resulted in preferential activation of CD8+ and CD4+ T cells within distinct LN regions. Because MHC I–specialized DCs are positioned in regions with limited antigen delivery, modest reductions in antigen dose led to a substantially greater decline in CD8+ compared with CD4+ T cell activation, expansion, and clonal diversity. Thus, the collective action of antigen dispersal and DC positioning regulates the extent and quality of T cell immunity, with important implications for vaccine design.
Z-scores-based methods and their application to biological monitoring: an example in professional soccer players
Authors: Saulière Guillaume , Dedecker Jérôme , Marquet Laurie-Anne , Rochcongar Pierre , Toussaint Jean-Francois , Berthelot Geoffroy
Published: August 2017

The clinical and biological follow-up of individuals, such as the biological passport for athletes, is typically based on the individual and longitudinal monitoring of hematological or urine markers. These follow-ups aim to identify abnormal behavior by comparing the individual’s biological samples to an established baseline. These comparisons may be done via different ways, but each of them requires an appropriate extra population to compute the significance levels, which is a non-trivial issue. Moreover, it is not necessarily relevant to compare the measures of a biomarker of a professional athlete to that of a reference population (even restricted to other athletes), and a reasonable alternative is to detect the abnormal values by considering only the other measurements of the same athlete. Here we propose a simple adaptive statistic based on maxima of Z-scores that does not rely on the use of an extra population. We show that, in the Gaussian framework, it is a practical and relevant method for detecting abnormal values in a series of observations from the same individual. The distribution of this statistic does not depend on the individual parameters under the null hypothesis, and its quantiles can be computed using Monte Carlo simulations. The proposed method is tested on the 3-year follow-up of ferritin, serum iron, erythrocytes, hemoglobin, and hematocrit markers in 2577 elite male soccer players. For instance, if we consider the abnormal values for the hematocrit at a 5% level, we found that 5.57% of the selected cohort had at least one abnormal value (which is not significantly different from the expected false-discovery rate). The approach is a starting point for more elaborate models that would produce a refined individual baseline. The method can be extended to the Gaussian linear model, in order to include additional variables such as the age or exposure to altitude. The method could also be applied to other domains, such as the clinical patient follow-up in monitoring abnormal values of biological markers.
De novo PacBio long-read and phased avian genome assemblies correct and add to reference genes generated with intermediate and short reads
Authors: Korlach Jonas , Gedman Gregory , Kingan Sarah B. , Chin Chen-Shan , Howard Jason T. , Audet Jean-Nicolas , Cantin Lindsey , Jarvis Erich D.
Published: August 2017

Reference-quality genomes are expected to provide a resource for studying gene structure, function, and evolution. However, often genes of interest are not completely or accurately assembled, leading to unknown errors in analyses or additional cloning efforts for the correct sequences. A promising solution is long-read sequencing. Here we tested PacBio-based long-read sequencing and diploid assembly for potential improvements to the Sanger-based intermediate-read zebra finch reference and Illumina-based short-read Anna's hummingbird reference, 2 vocal learning avian species widely studied in neuroscience and genomics. With DNA of the same individuals used to generate the reference genomes, we generated diploid assemblies with the FALCON-Unzip assembler, resulting in contigs with no gaps in the megabase range, representing 150-fold and 200-fold improvements over the current zebra finch and hummingbird references, respectively. These long-read and phased assemblies corrected and resolved what we discovered to be numerous misassemblies in the references, including missing sequences in gaps, erroneous sequences flanking gaps, base call errors in difficult-to-sequence regions, complex repeat structure errors, and allelic differences between the 2 haplotypes. These improvements were validated by single long-genome and transcriptome reads and resulted for the first time in completely resolved protein-coding genes widely studied in neuroscience and specialized in vocal learning species. These findings demonstrate the impact of long reads, sequencing of previously difficult-to-sequence regions, and phasing of haplotypes on generating the high-quality assemblies necessary for understanding gene structure, function, and evolution.
Sleep Disorders Among Holocaust Survivors
Authors: Lurie Ido
Published: August 2017

After World War II, traumatic after effects often caused persistent sleep disorders for Holocaust survivors (HSs). This is a review of studies reporting on sleep disturbances and nightmares (as primary or secondary outcomes) among HSs between 1939 and 2015, conducted in various countries and contexts (clinical settings, pension claims, community surveys, sleep laboratories). Most studies revealed various sleep disturbances among HSs. Some studies found those disturbances in the absence of clinical disorders. Both men and women reported similar frequencies of sleep disturbances, although posttraumatic stress disorder and depression were more frequent in women. Sleep laboratory studies provided the single most direct and detailed sources of information. Findings included a) long-standing changes in sleep architecture, for example, decreased rapid eye movement (REM) sleep, and b) contrasting patterns of dreaming and recall among better versus poorly adjusted survivors. These results are of importance to both HSs and their families and for medical and mental health professionals.