bluuebunny/crossref_metadata_2025 huggingface dataset:
Prothrombin Time Standardization Report of the Expert Panel on Oral Anticoagulant Control: A Minority Opinion
Authors: Miale John B
Published: August 2018

The ICTH/ICSH collaborative study failed to achieve its aims because each combination of plasma, thromboplastin and method was tested by too few laboratories in relation to intra and inter laboratory variation, and because the stability of the reference thromboplastin 70/178 is suspect. The evidence of the study does not support the superiority of reference thromboplastins over reference plasmas, but the concept of reference plasma was not adequately explored.
Interaction of Bovine Platelets with Bovine Glomerular Basement Membrane
Authors: Davis J Laurence , Chandler Donna K F , Riquetti Patrick , Rogers Stearns , Kocan Katherine M , Ownby Charlotte L , Hudson Billy G , Carraway Kermit L
Published: August 2018

The interaction of bovine platelets with bovine glomerular basement membrane has been studied by aggregometry, transmission and scanning electron microscopy and measurement of [3H] serotonin release. In the absence of added calcium platelets adhere to basement membrane but fail to undergo the release reaction or aggregation. In the presence of 0.2-0.5 mM calcium release of serotonin and complete aggregation of the platelets are observed when sufficient basement membrane is present. Platelets were strongly adhered to the basement membrane surface, the platelet surface in the aggregates closely following the surface of the basement membrane. Platelet morphology in aggregates with basement membrane closely resembled that of platelets from collagen-induced aggregates. Basement membrane differed from collagen in its requirement for calcium for the aggregation and release reactions. In addition purified basement membrane was 1.5-3 fold less active on a weight basis than bovine tendon collagen in promoting aggregation.
The Influence of Thrombin on the Platelet-Aggregating Activity of Human Factor VIII. A Study with Insolubilized Thrombin
Authors: Vukovich Th , Koller E , Doleschel W
Published: August 2018

A study was made of the influence of thrombin on the platelet-aggregating activity of human factor VIII with Ristocetin as cofactor. Purified factor VIII and different amounts of a thrombin-Sepharose 2B complex were mixed and incubated for various periods of time. The factor VIII-related platelet-aggregating activities of the filtrates of the incubation mixtures were determined in a test system using formalin-fixed platelets and Ristocetin as cofactor. The results so obtained indicate that thrombin inactivates the platelet-aggregating activity of factor VIII. The filtrates of the incubation mixtures were also tested by a two- stage test system for their clotting activities. Comparison of the influence of thrombin on the clotting- and the platelet-aggregating activities of factor VIII is presented and discussed.
What Are the Options for the Treatment of Stuttering in Preschool Children?
Authors: Santayana Gissella , Shenker Rosalee
Published: August 2018

Treatment of stuttering during the preschool years is considered to be the best prevention of persistent chronic stuttering; however, many clinicians do not feel comfortable treating stuttering and may be confused about choosing an intervention. This article summarizes the history of direct and indirect methodology for treatment of stuttering in preschool children. It provides an update of contemporary treatments and discusses issues related to the timing of treatment. Guidelines for choosing a level of treatment based on the risk of a preschool child continuing to stutter are discussed, with examples of which children would be most appropriate for which level of intervention.
What Can Stutterers Learn from the Neurodiversity Movement?
Authors: Constantino Christopher
Published: August 2018

Neurodiversity is both an empowerment movement and a way of thinking about disability. Rather than focusing on pathology and impairment, neurodiversity emphasizes natural variation and the unique skills, experiences, and traits of neurodivergent individuals. People who stutter are beginning to work with and derive value from these concepts. In this article, we look at the history of neurodiversity and its key ideas. We discuss the conventional view of disability, the medical model, which situates disability within the individual as pathology. We also take up social and relation models of disability, which situate disability in social oppression or mismatches between individuals and their environment. Neurodiversity has not been without controversy. We look at some of the disagreements surrounding issues of intervention and cure. The ideas of neurodiversity are applied to stuttering, and a case example illustrating therapy using these ideas is given. We conclude that therapy should focus on subject's well-being and not normalization of superficial behaviors.
A Study to Analyze the Tentorial Incisura in Indian Population, for Racial Differences and Its Impact in the Outcome of Patients with Head Injury
Authors: Kunjithapatham Deiveegan , Pachiyappan Jeyaselvasenthilkumar , Fernand Maria
Published: August 2018

Aim To measure the size of tentorial notch in Indian population, compare it with the western population from the literature available, and analyze the relation between size of tentorial notch and the outcome in patients with head injury.

Materials and Methods The study was done using 10 cadavers and 15 autopsy specimens. In all the specimens, tentorial incisura was measured using vernier caliper after opening the skull and cutting the midbrain at the level of tentorial edge carefully without damaging the tentorium. All measurements were done in millimeters.

Results Mean values, age-dependent mean values, and percentile values were calculated for various parameters in the tentorial incisura. Majority of the tentorial incisura are of typical type. Cases of tentorial incisura are significantly smaller in the age group of 20 to 25 years. Rate of deterioration of Glasgow coma scale (GCS) is rapid when the tentorial incisura is large.

Conclusion There were no significant variations in measurements of tentorial incisura in Indian population compared with the western population. Rate of deterioration of GCS is higher in patients who had large tentorial incisura compared with other groups, which is statistically significance. However, this is to be confirmed by further study using large groups of patients to be used for clinical applications.
Tumor to Cerebellar Peduncle T2-Weighted Imaging Intensity Ratio Fails to Predict Pituitary Adenoma Consistency
Authors: Mastorakos Panagiotis , Mehta Gautam U. , Chatrath Ajay , Moosa Shayan , Lopes Maria-Beatriz , Payne Spencer C. , Jane John A.
Published: August 2018

Object The consistency of pituitary macroadenomas affects the complexity of surgical resection. On T2-weighted (T2W) imaging, the intensity ratio of the tumor to the cerebellar peduncle (tumor to cerebellar peduncle T2-weighted imaging intensity [TCTI] ratio) correlates with meningioma consistency. We aimed to determine the correlation of this radiographic finding with pituitary macroadenoma consistency and to determine whether it can be used for preoperative planning.

Methods We performed a retrospective evaluation of 196 patients with macroadenomas who underwent endoscopic transsphenoidal resection from January 2012 to June 2017. Macroadenoma consistency was determined by one senior neurosurgeon at the time of surgery. Axial and coronal T2W magnetic resonance imaging images were evaluated retrospectively, and adenoma size, Knosp grade, suprasellar extension and TCTI were calculated.

Results The mean TCTI ratio was 1.70 (95% confidence interval [CI]: 1.65–1.75). Intraoperatively, 140 (71.4%) adenomas were classified as soft and 48 (24.5%) as fibrous. Gross total resection was achieved in 66.7% of fibrous adenomas and in 86.4% of soft adenomas (p = 0.007). The mean ratio was 1.68 (95% CI: 1.62–1.74) for soft tumors and 1.76 (95%CI: 1.67–1.84) for fibrous tumors. There was no difference in the mean TCTI ratio between groups. Lactotroph and somatotroph adenomas had a lower mean TCTI ratio compared with other functioning and nonfunctioning adenomas with a mean TCTI of 1.52 compared with 1.77.

Conclusions In this retrospective cohort study, we found that the TCTI ratio does not correlate with tumor consistency. We also noted that the TCTI ratio is increased in prolactin and growth hormone-secreting adenomas.
Conservative Surgical Treatment of a Case of Placenta Accreta
Authors: Biyik Ismail , Keskin Fatih , Keskin Elif Usturali
Published: August 2018

Placenta accreta syndromes are associated with increased maternal mortality and morbidity. Cesarean hysterectomy is usually performed in cases of placenta accreta syndrome. Fertility sparing methods can be applied. In the present study, we report a successful segmental uterine resection method for placenta accreta in the anterior uterine wall in a cesarean section case. A 39-year-old woman underwent an elective cesarean section at 38 + 2 weeks. A placental tissue with an area of 10 cm was observed extending from the anterior uterine wall to the serosa, 2 cm above the uterine incision line. The placental tissue was removed with the help of monopolar electrocautery. The uterine incision was continuously sutured. The patient was discharged on the second postoperative day. The placental pathology was reported as placenta accreta. The American College of Obstetricians and Gynecologists (ACOG) generally recommends cesarean section hysterectomy in cases of placenta accreta because removal of placenta associated with significant hemorrhage. Conservative and fertility sparing methods include placenta left in situ, cervical inversion technique and triple-P procedure. There are several studies reporting that segmental uterine resection is performed with and without balloon placement or artery ligation. Segmental uterine resection may be an alternative to cesarean hysterectomy to preserve fertility or to protect the uterus in cases of placenta accreta when there is no placenta previa.
Prognostic Factors in Paranasal Sinus Squamous Cell Carcinoma and Adenocarcinoma: A SEER Database Analysis
Authors: Jain Sumit , Li Yan , Kuan Edward C. , Tajudeen Bobby A. , Batra Pete S.
Published: August 2018

Background Outcome studies on sinonasal malignancy are limited to retrospective case series, often with inclusion of diverse histology and short follow-up. The objective of this study was to identify key predictive variables that independently impact survival for paranasal sinus squamous cell carcinoma (SCC) and adenocarcinoma (AC) and to compare these variables in the context of these two distinct clinicopathologic entities.

Methods: Analysis was conducted using the Surveillance, Epidemiology, and End Results database from 1973 to 2012 to identify key variables that impact survival for SCC and AC.

Results A total of 3,714 cases were included. There were 2,895 SCC cases and 819 AC cases. The mean age at diagnosis was 64.1 years. The male to female ratio for SCC and AC was 1.85 and 1.04, respectively. Patients with SCC and AC were most often diagnosed with stage IV disease in 61.8 and 63.4% of cases, respectively. The majority of patients received combined surgery and radiation (52% for SCC and 43.1% for AC). For SCC, increased age (p < 0.001) and stage (p < 0.001) were negative predictors, and surgery improved survival (p < 0.001) on multivariate analysis. For AC, prognostic factors associated with worse survival include increased age (p < 0.001) and grade (p < 0.001) on multivariate analysis. Overall survival was significantly higher in AC compared with SCC at 5 years (p = 0.001).

Conclusion SCC and AC of the paranasal sinuses are both aggressive malignancies with poor survival. For both histological subtypes, increased age predicts worse survival and grade also closely links to survival in AC. These data have important potential implications for treatment planning and pretreatment counseling.
Morphologic Characteristics of the Submandibular Salivary Gland of the Collared Peccary (Tayassu Tajacu)
Authors: Reginato Gabriela de Souza , Bolina Cristina de Sousa , Oliveira Moacir Franco , Almeida Sonia Regina Yokomizo , Watanabe Ii-sei , Ciena Adriano Polican
Published: August 2018

Introduction Most salivary glands is located on the inside and around the oral cavity, and are divided into major and minor salivary glands. The aim of the present study was to describe the structural and ultrastructural morphological characteristics of the lingual tissue of the submandibular glands of the collared peccary (Tayassu tajacu).

Materials and Methods The submandibular glands (n = 10) of adult male collared peccaries (
T. tajacu) were used for histological and ultrastructural analysis. The techniques used were light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

Results The submandibular salivary glands of the collared peccary (T. tajacu) showed a capsule formed by a connective tissue containing the acinus and duct cells. Histologically, the nuclei located at the basal region of the cells was observed. The light polarized microscopy clearly showed the presence of type I and type III collagen. In the SEM image, the submandibular salivary gland revealed a round aspect separated in several lobules with bundles of collagen fibers. The vibratome sections showed the groupings of acinar cells, with intermingled secretory ducts containing vessels of different diameters. The secretory granules were noted in the apical portion of the acinar and ductal cells. The thick bundles of collagen fibers formed a glandular capsule and were identified around of the acinar and ductal cells in three-dimensional SEM images. The TEM images showed a number of secretory granules, especially in the apical region of the cytoplasm of the acinar cells and in the basal portion of the nuclei. The granular endoplasmic reticulum area, the euchromatic nuclei and the cytoplasmic projections may be seen. Mucous acinar cells separated by fine collagen fibers were also observed.

Conclusion The morphological characteristics of the submandibular gland of the collared peccary is similar to that of other mammals with the same eating habits and habitat.
Aktuelle Konzepte zur Behandlung von Haut- und Weichteilinfektionen in Orthopädie und Unfallchirurgie
Authors: von Rüden Christian , Kühl Richard , Erichsen Christoph , Kates Stephen , Hungerer Sven , Morgenstern Mario
Published: August 2018

Haut- und Weichteilinfektionen reichen von leichten oberflächlichen Entzündungen bis hin zu tiefen nekrotisierenden Entzündungen mit schweren systemischen Komplikationen. Ziel dieser Arbeit ist, diese im klinischen Alltag rasch zu diagnostizieren und drohende fatale Krankheitsverläufe zu erkennen, die ursächlichen Krankheitserreger zu identifizieren und rechtzeitig eine adäquate antimikrobielle und ggf. chirurgische Therapie einzuleiten.
Novel ultra-wideband test fixture and method for attenuation of the attenuator-coated dielectric support rod in a helical slow-wave structure
Authors: Gao Chong , Li En , Zhang Yunpeng , Yu Chengyong , Gao Yong
Published: August 2018

In order to measure the attenuation along the dielectric support rod in a helical slow-wave structure, a new test fixture and the corresponding test method are introduced. The proposed fixture is a transmission line that consists of three parts: angle gradient transitions, hyperbolical tapered lines, and parallel strips with a sample hole in the middle. The hyperbolical tapered lines on the top and bottom sides of the substrate were designed to realize an approximate Klopfenstein tapered line. The parallel strips provide a relatively reasonable electric field for measuring the attenuation of the dielectric support rod. Meanwhile, two modified metal blocks on both sides of each connector are designed to suppress unwanted radiation. The test fixture works in the ultra-wideband range from 7 GHz to 40 GHz, and it exhibits an insertion loss of less than 3 dB and a return loss of more than 10 dB over the whole frequency range. The sample hole was regarded as the mutually coupled parallel strip pairs (a four-port network), and the odd-even mode method was used to analyze the scattering parameters of the single parallel strip. The dielectric support rod deposited by the resistive thin-film was measured with the experimental test setup developed in this paper. Compared with the method of the double ridge waveguide, the measured results present a great agreement with the actual distribution of the attenuation in the length ranges from 12 mm to 15 mm, 25 mm to 27 mm, and 46 mm to 52 mm, and the differences in other length ranges are explained.
Recurrence plots for the assessment of patient-ventilator interactions quality during invasive mechanical ventilation
Authors: Carvalho Nadja C. , Portes Leonardo L. , Beda Alessandro , Tallarico Lucinara M. S. , Aguirre Luis A.
Published: August 2018

Inappropriate patient-ventilator interactions’ (PVI) quality is associated with adverse clinical consequences, such as patient anxiety/fear and increased need of sedative and paralytic agents. Thus, technological devices/tools to support the recognition and monitoring of different PVI quality are of great interest. In the present study, we investigate two tools based on a recent landmark study which applied recurrence plots (RPs) and recurrence quantification analysis (RQA) techniques in non-invasive mechanical ventilation. Our interest is in how this approach could be a daily part of critical care professionals’ routine (which are not familiar with dynamical systems theory methods and concepts). Two representative time series of three typical PVI “scenarios” were selected from 6 critically ill patients subjected to invasive mechanical ventilation. First, both the (i) main signatures in RPs and the (ii) respective signals that provide the most (visually) discriminant RPs were identified. This allows one to propose a visual identification protocol for PVIs’ quality through the RPs’ overall aspect. Support for the effectiveness of this visual based assessment tool is given by a RQA-based assessment tool. A statistical analysis shows that both the recurrence rate and the Shannon entropy are able to identify the selected PVI scenarios. It is then expected that the development of an objective method can reliably identify PVI quality, where the results corroborate the potential of RPs/RQA in the field of respiratory pattern analysis.
Detection of unstable periodic orbits in mineralising geological systems
Authors: Oberst S. , Niven R. K. , Lester D. R. , Ord A. , Hobbs B. , Hoffmann N.
Published: August 2018

Worldwide, mineral exploration is suffering from rising capital costs, due to the depletion of readily recoverable reserves and the need to discover and assess more inaccessible or geologically complex deposits. For gold exploration, this problem is particularly acute. We propose an innovative approach to mineral exploration and orebody characterisation, based on the analysis of geological core data as a spatial dynamical system, using the mathematical tools of dynamical system analysis. This approach is highly relevant for orogenic gold deposits, which—in contrast to systems formed at chemical equilibrium—exhibit many features of nonlinear dynamical systems, including episodic fluctuations on various length and time scales. Feedback relationships between thermo-chemical and deformation processes produce recurrent fluid temperatures and pressures and the deposition of vein-filling minerals such as pyrite and gold. We therefore relax the typical assumption of chemical equilibrium and analyse the underlying processes as aseismic, non-adiabatic, and inherent to a hydrothermal, nonlinear dynamical open-flow chemical reactor. These processes are approximated using the Gray-Scott model of reaction-diffusion as a complex toy system, which captures some of the features of the underlying mineralisation processes, including the spatiotemporal Turing patterns of unsteady chemical reactions. By use of this analysis, we demonstrate the capability of recurrence plots, recurrence power spectra, and recurrence time probabilities to detect underlying unstable periodic orbits as one sign of deterministic dynamics and their robustness for the analysis of data contaminated by noise. Recurrence plot based quantification is then applied to three mineral concentrations in the core data from the Sunrise Dam gold deposit in the Yilgarn region of Western Australia. Using a moving window, we reveal the episodic recurring low-dimensional dynamic structures and the period doubling route to instability with depth, embedded in and originating from higher-dimensional processes of the complex mineralisation system.
AC magnetic field sensing using continuous-wave optically detected magnetic resonance of nitrogen-vacancy centers in diamond
Authors: Saijo Soya , Matsuzaki Yuichiro , Saito Shiro , Yamaguchi Tatsuma , Hanano Ikuya , Watanabe Hideyuki , Mizuochi Norikazu , Ishi-Hayase Junko
Published: August 2018

Nitrogen-vacancy (NV) centers in diamond can be used as highly sensitive quantum sensors for detecting magnetic fields at room temperature. Pulsed optically detected magnetic resonance (ODMR) is typically used to detect AC magnetic fields, but can only be implemented after careful calibration that involves aligning an external static magnetic field, measuring continuous-wave (CW) ODMR, determining the Rabi frequency, and setting the microwave phase. In contrast, CW-ODMR can be simply implemented by continuous application of a green CW laser and a microwave field, and can be used to detect DC or low-frequency (kHz-range) AC magnetic fields. We report a method that uses NV centers and CW-ODMR to detect high-frequency (MHz-range) AC magnetic fields. This method fully utilizes spin-1 properties of electron spins of NV centers. Unlike conventional methods, the proposed method does not require a pulse sequence; this greatly simplifies the procedure and apparatus needed for implementation. A sensitivity of 2.5 μT/Hz is found for our present experimental apparatus, the sensitivity of which is currently limited by inhomogeneous broadening and low measurement contrast of samples used and by the low collection efficiency of the optical setup, both of which could be improved in the future. Thus, this simple alternative to existing AC magnetic field sensors paves the way for the development of a practical and feasible quantum sensor.
Analysis of diagonals in cross recurrence plots between heart rate and systolic blood pressure during supine position and active standing in healthy adults
Authors: González-Gómez Gertrudis Hortensia , Infante Oscar , Martínez-García Paola , Lerma Claudia
Published: August 2018

The inter beat interval (IBI) duration and systolic blood pressure (SBP) are cardiovascular variables related through several feedback mechanisms. We propose the analysis of diagonal lines in cross recurrence plots (CRPs) from IBI and SBP embedded within the same phase space to identify events where trajectories of both variables concur. The aim of the study was to describe the relationship between IBI and SBP of healthy subjects using CRP and diagonal analysis during baseline condition—supine position (SP)—and how the relationship changes during the physiological stress of active standing (AS). IBI and SBP time series were obtained from continuous blood pressure recordings during SP and AS (15 min each) in 19 young healthy subjects. IBI and SBP time series were embedded within a five-dimensional phase space using an embedding delay estimated from cross correlation between IBI and SBP. During SP, mean CRP showed high determinism (≥85%) and also brief but repeated events where both variables stay within a reduced space. Most quantitative recurrences analysis indexes of CRP increased significantly (p < 0.05) during AS. CRP analysis showed short diagonals indicating a very strong deterministic relationship between IBI and SBP with intermittent unlocking periods. The strength of IBI and SBP relationship increased during the physiological stress of AS. The CRP method allowed a rigorous quantitative description of the deterministic association between these two variables. Diagonal lines were intermittent and not always parallel, showing that there is not a defined and unique rhythm. This suggests the activation of different influences at different times and with different precedence between the heart rate and blood pressure in response to AS.
Terahertz wire-grid circular polarizer tuned by lock-in detection method
Authors: Tesař R. , Šindler M. , Koláček J. , Skrbek L.
Published: August 2018

We report the design, construction, and testing of a broadband-tunable terahertz circular polarizer, which we developed for our magneto-optical measurements using the far-infrared/THz laser source in the range of 0.25–7.5 THz. We present a thorough analysis of the lock-in amplifier signal generated by using a rotating analyzer with regard to setting the desired state of polarization. The phase-sensitive detection method is applied to a combination of a wire-grid polarizer and a parallel translation mirror providing a tunable retardance. The proposed technique is appropriate not only to free-standing grids but also to those deposited on transparent substrates which may introduce additional non-linear effects. The method is preferred when the distance between the mirror and the grid cannot be exactly determined, but the relative displacements are measured. The device enables switching between left- and right-handed polarization states on a time scale of a few seconds. Practical use of the circular polarizer is demonstrated by directly probing the far infra-red magneto-optical properties of the two-dimensional electron gas on the 458 μm laser line.
Ultrafast time-resolved fluorescence at cryogenic temperature
Authors: Son Jiwon , Joo Taiha
Published: August 2018

Time resolved fluorescence at low temperature can be a powerful tool for the study of dynamics and spectroscopy. We have developed a time resolved fluorescence apparatus that provides a time resolution of 45 fs at cryogenic temperature, which is comparable to the best time resolution at ambient temperature. A continuous flow cryostat with a customized vacuum shroud and fluorescence upconversion gating by sum frequency generation were employed. A reflective Cassegrain type microscope objective lens was used to collect and to image the fluorescence to achieve high time resolution. It was demonstrated that time-resolved fluorescence spectra can also be measured directly without the spectra reconstruction at the same time resolution by in situ adjustment of the time delay to compensate the group velocity dispersion. Heat dissipation of the sample holder and the actual temperature of the irradiated volume were estimated by measuring the steady-state emission spectra of prodan solution in two different sample thicknesses, which provides a design consideration for the sample cell. The time-resolved fluorescence spectra of prodan, which undergoes charge transfer in the excited state, were measured at low temperature to demonstrate the capability of the apparatus.
Nonlinear waves in a model for silicate layers
Authors: Archilla Juan F. R. , Zolotaryuk Yaroslav , Kosevich Yuriy A. , Doi Yusuke
Published: August 2018

Some layered silicates are composed of positive ions, surrounded by layers of ions with opposite sign. Mica muscovite is a particularly interesting material, because there exist fossil and experimental evidence for nonlinear excitations transporting localized energy and charge along the cation rows within the potassium layers. This evidence suggests that there are different kinds of excitations with different energies and properties. Some of the authors proposed recently a one-dimensional model based on physical principles and the silicate structure. The main characteristic of the model is that it has a hard substrate potential and two different repulsion terms, between ions and nuclei. In a previous work with this model, it was found the propagation of crowdions, i.e., lattice kinks in a lattice with substrate potential that transport mass and charge. They have a single specific velocity and energy coherent with the experimental data. In the present work, we perform a much more thorough search for nonlinear excitations in the same model using the pseudospectral method to obtain exact nanopteron solutions, which are single kinks with tails, crowdions, and bi-crowdions. We analyze their velocities, energies, and stability or instability and the possible reasons for the latter. We relate the different excitations with their possible origin from recoils from different beta decays and with the fossil tracks. We explore the consequences of some variation of the physical parameters because their values are not perfectly known. Through a different method, we also have found stationary and moving breathers, that is, localized nonlinear excitations with an internal vibration. Moving breathers have small amplitude and energy, which is also coherent with the fossil evidence.
Profiling exciton generation and recombination in conventional and inverted bulk heterojunction organic solar cells
Authors: Mehdizadeh Rad Hooman , Zhu Furong , Singh Jai
Published: August 2018

Applying the optical transfer matrix method and the drift-diffusion equations, the efficient light absorption, exciton generation, and recombination rate in bulk heterojunction (BHJ) organic solar cells (OSCs) with conventional and inverted configurations are studied. Analysing the influence of the electric field component of the electromagnetic radiation propagating through the layered structure of BHJ OSCs and using contour plots of normalized modulus squared of the electric field, the constructive interference points (CIPs) which represent the positions of maximum absorption of photons and hence generation of excitons within the active layer are investigated for both the conventional and inverted OSCs. Also, the influence of the thicknesses of other layers in both the inverted and conventional structures is investigated. It is found that except the thickness of MoO3 in the inverted structure the thicknesses of other layers do not have any significant influence on CIPs. The maximum CIP occurs at an active layer thickness of 190 nm, regardless of the thickness of the second layer, which is MoO3, Ag, or ITO in the inverted structure and PEDOT:PSS, Al, or ITO in the conventional structure. The results of 3D plots of the normalized modulus squared of the electric field reveal that the absorption of photons at the end of the active layer in the inverted structure is higher than that in the conventional structure for all the effective wavelengths and different active layer thicknesses. It is expected that this study provides a deeper understanding of exciton generation within the two structures.
Enhanced photoelectrochemical performance of InGaN-based nanowire photoanodes by optimizing the ionized dopant concentration
Authors: Zhang Huafan , Ebaid Mohamed , Min Jung-Wook , Ng Tien Khee , Ooi Boon S.
Published: August 2018

InGaN-based nanowires (NWs) have been extensively studied for photoelectrochemical (PEC) water splitting devices owing to their tunable bandgap and good chemical stability. Here, we further investigated the influence of Si doping on the PEC performance of InGaN-based NW photoanodes. The Si dopant concentration was controlled by tuning the Si effusion cell temperature (TSi) during plasma-assisted molecular beam epitaxy growth and further estimated by Mott-Schottky electrochemical measurements. The highest Si dopant concentration of 2.1 × 1018 cm−3 was achieved at TSi = 1120 °C, and the concentration decreased with further increases in TSi. The flat-band potential was calculated and used to estimate the conduction and valence band edge potentials of the Si-doped InGaN-based NWs. The band edge potentials were found to seamlessly straddle the redox potentials of water splitting. The linear scan voltammetry results were consistent with the estimated carrier concentration. The InGaN-based NWs doped with Si at TSi = 1120 °C exhibited almost 9 times higher current density than that of the undoped sample and a stoichiometric evolution of hydrogen and oxygen gases. Our systematic findings suggest that the PEC performance can be significantly improved by optimizing the Si doping level of InGaN-based NW photoanodes.
Wavevector and polarization resolved analysis of phonon scattering from embedded nanoparticles
Authors: Kakodkar Rohit R. , Feser Joseph P.
Published: August 2018

Embedded nanocrystals are capable of dramatically reducing the thermal conductivity of alloy semiconductors through increased phonon scattering, but many aspects of thermal wavelength phonon interactions with embedded nanoparticles remain understudied. Here, the wavevector- and polarization-resolved capabilities of the Frequency Domain Perfectly Matched Layer (FDPML) computational technique are exploited to study several fundamentally important phonon scattering problems across the entire Brillouin zone. We compare the atomistic predictions of FDPML against continuum mechanics approaches for spherically embedded particles. For long to mid-wavelength phonons, reasonable agreement is found with continuum theories that consider the Mie regime accurately, while commonly used “patching” theories which empirically connect the Rayleigh scattering to the geometric limit are shown to have poor agreement with more rigorous approaches. Next, the scattering cross section of optical phonons from nanoparticles is explored for the first time. We show that the scattering behavior of optical phonons is fundamentally different than their acoustic counterparts in that long wavelength optical phonons exhibit a scattering cross section nearly independent of wavelength, which we interpret as being due to zone folding of short wavelength acoustic modes from the geometric scattering regime into long wavelength optical modes. Finally, we study the scattering cross section of nanoparticles exhibiting atomic interdiffusion at the matrix-particle interface, where we find that interdiffusion both suppresses Mie oscillations and substantially increases the scattering cross section at short wavelength, compared to a solid nanoparticle with the same number of impurity atoms.
In situ lift-off of InAs quantum dots by pulsed laser irradiation
Authors: Deng Changwei , Shi Zhenwu , Yang Linyun , Zhang Wei , Chen Chen , Miao Lili , Yang Xinning , Wang Chinhua , Chen Linsen , Peng Changsi
Published: August 2018

InAs/GaAs quantum dots (QDs) grown by molecular beam epitaxy were subjected to in situ irradiation using a mono-beam pulsed laser. The evolution of the QD morphology was investigated as a function of irradiation intensity at temperatures of 525 °C and 480 °C. The temperature was found to exert a considerable influence on the reaction of the QDs to the irradiation. At the higher temperature (525 °C), both the height and width of the InAs QDs gradually decreased with increasing irradiation intensity, which was ascribed to the dominant effect of the laser desorption of indium. In contrast, at the lower temperature (480 °C), the height of the InAs islands decreased with increasing irradiation intensity while the width exhibited unexpected broadening, which was attributed to a combination of laser desorption and laser diffusion of indium. Remarkably, at the higher temperature, laser irradiation above a certain threshold intensity resulted in the lift off of the InAs QDs to afford a clear, smooth, and perfect GaAs surface. Through subsequent growth of QDs on this surface, it was found that the QDs exhibited the same nucleation properties and optical quality as the common Stranski–Krastanov mode on an as-prepared GaAs surface. Therefore, we have developed a technology for the damage-resistant fabrication of QDs using in situ pulsed laser irradiation (LIR), which is expected to find potential applications in the manufacture of patterned QDs upon upgrading the mono-beam irradiation to multi-beam interference irradiation in the future.
Development of a multi-channel capacitive probe for electric field measurements with fine spatial and high time resolution
Authors: Nishizawa T. , Almagri A. F. , Goodman W. , Ohshima S. , Sarff J. S.
Published: August 2018

A capacitive probe [Tan et al., Rev. Sci. Instrum. 88, 023502 (2017)] is one of a few diagnostics that is directly sensitive to the plasma potential. Using this diagnostic technique, a Multi-channel Linear Capacitive Probe (MLCP) is developed for turbulence measurements. The MLCP has 10 spatial channels and provides 9 points of radial electric field measurements simultaneously with a spatial step of 7 mm. A new readout circuit and a correction technique for low frequency attenuation are also developed to achieve the required spatial and time resolution. A performance test of the MLCP using a reversed field pinch plasma confirms that the MLCP resolves sub-centimeter structures of the equilibrium radial electric field profile and fluctuations up to 680 kHz.
Two-dimensional electron density visualization over plasma flare in vacuum breakdown process
Authors: Inada Y. , Kamiya T. , Matsuoka S. , Kumada A. , Ikeda H. , Hidaka K.
Published: August 2018

Spatiotemporal evolution of plasma flares in a vacuum breakdown process was characterized by various optical techniques including Shack-Hartmann type laser wavefront sensors for two-dimensional electron density imaging, high-speed framing photography for speed determination of flare expansion, and optical emission spectroscopy for plasma composition assessment. The experimental results showed that the plasma flares with high electron densities of 1025 m−3 and gas temperature of 2 eV were initiated on the copper anode and expanded to the vacuum gap with a propagation speed of 6 × 103 m/s. Subsequently, the electron densities in the anode flare tips demonstrated a drastic decrease in a short time scale of 50 ns due to a three-body recombination reaction. The anode flare tips combined with the cathode plasma flares initiated on the copper cathode, and the conductive plasma channels containing flare-induced copper vapor were established in the interelectrode gap. In the final stage of the vacuum breakdown, the copper-vapor-contaminating plasmas were deconstructed and they transformed into the vacuum arc discharges.
Cascade capture of charge carriers in highly doped semiconductors
Authors: Orlova E. E. , Kelsall R. W. , Deßmann N. , Pavlov S. G. , Hübers H.-W. , Zhukavin R. Kh. , Shastin V. N.
Published: August 2018

We analyze the cascade capture of charge carriers due to the interaction with acoustic phonons in highly doped semiconductors using a model that describes the recombination of photo-ionized carriers as a continuous relaxation of carriers in the energy space at both positive and negative energies in the field of a set of impurity ions. Such description enables simultaneous calculation of non-equilibrium carrier distribution formed by interaction with acoustic phonons in the presence of impurity traps, and the time of recombination in a wide range of concentrations of capture centers and phonon temperatures. Additionally, we calculated the time of cascade recombination in the presence of fast scattering processes forming a Maxwellian distribution of free carriers. We show that experimentally observed concentration and temperature dependence of carrier life times in highly doped semiconductors can be described within the model of the cascade capture to uniformly spaced capture centers, and the main factor that determines the regime of cascade capture is the ratio of the thermal energy and the energy of the overlap of impurity potentials.
Millimeter-wave system-on-chip advancement for fusion plasma diagnostics
Authors: Yu J.-H. , Chang Y.-T. , Lin K.-Y. , Chang C.-C. , Chang S.-F. , Ye Y. , Pham A. V. , Tobias B. J. , Zhu Y. , Domier C. W. , Luhmann N. C.
Published: August 2018

Recent advances in radio-frequency system-on-chip technology have provided mm-wave fusion plasma diagnostics with the capability to overcome major challenges such as space inefficiency, inflexible installation, sensitivity, susceptibility to EMI, and prohibitively high cost of conventional discrete component assemblies as higher imaging resolution and data accuracy are achieved by increasing the number of channels. Nowadays, shrinking transistor gate lengths on fabrication techniques have enabled hundreds of GHz operation, which is suitable for millimeter-wave diagnostics on current and future tokamaks. The Davis Millimeter Wave Research Center (DMRC) has successfully developed V-band (55-75 GHz) transmitter and receiver chips for Microwave Imaging Reflectometer (MIR) instruments. The transmitter can illuminate 8 different frequencies simultaneously within 55-75 GHz. Moreover, the receiver has the capability to amplify the reflected signal (>30 dB) while offering 10-30× reduction in noise temperature compared to current MIR instruments. Plasma diagnostics requires ultra-wideband (more than 20 GHz) operation which is approximately nine times wider bandwidth than the recent commercial impetus for communication systems. Current efforts are underway for gallium-arsenide monolithic microwave integrated circuit receiver chips at W-band (75-110 GHz) and F-band (90–140 GHz) permitting measurements at higher toroidal magnetic fields.
Development of a three-wave far-infrared laser interferometry and polarimetry diagnostic system for the C-2W field-reversed configuration plasmas
Authors: Deng B. H. , Rouillard M. , Feng P. , Beall M. , Armstrong S. , Castellanos J. , Kinley J. , Leinweber H. K. , Ottaviano A. , Settles G. , Snitchler G. , Wells J. , Ziaei S. , Thompson M. ,   TAE Team
Published: August 2018

Great advancements in modern field-reversed configuration (FRC) experiments motivated the development of a 14-chord three-wave far infrared (FIR) laser interferometry and polarimetry diagnostic system, which can provide simultaneous high temporal resolution measurements of density and Faraday rotation profiles with high accuracy. The unique challenges facing FIR diagnostics in high beta FRC plasmas are the extremely small (<0.5°) Faraday rotation angles, and severe laser beam refraction effects due to high density gradient and choice of long wavelength. The diagnostic system design and development are described with methods to overcome the challenges, and initial experimental data are also presented.
Magneto-plasmonics on perpendicular magnetic nanostructures consisting of a CoPt layer and noble-metal grains
Authors: Yamane H. , Takeda K. , Isaji Y. , Yasukawa Y. , Kobayashi M.
Published: August 2018

The magneto-optical (MO) properties of perpendicular magnetic nanostructures consisting of a hexagonal close-packed Co80Pt20 nanolayer and noble-metal (Ag or Au) fine grains were investigated under polar Kerr measurement conditions. The samples exhibited an unusual MO hysteresis loop in which the Kerr rotation angle increased at a low magnetic field; this effect was observed in a different wavelength region for the CoPt–Ag and CoPt–Au samples. The nanostructures consisted of two magnetic regions of CoPt layers formed on the grains and on the underlayer. The increase in the Kerr angle was induced by the antiparallel magnetic alignment of these CoPt layers. The opposite MO polarity on the CoPt nanostructures was suggested in a micro-MO observation using scanning near-field polarized optical microscopy. The Ag and Au fine grains induced the MO phase reversal of CoPt in a different wavelength region for each sample. These MO behaviors were attributed to the influence of localized surface plasmons excited on the noble-metal grains. The magneto-plasmonic activities on the CoPt nanostructures were also affected by the underlayer material and the environmental conditions. The perpendicular magnetic nanostructures are expected to provide a new type of probe for chemical and biological sensing applications.
High-frequency measurements of thermophysical properties of thin films using a modified broad-band frequency domain thermoreflectance approach
Authors: Shahzadeh Mohammadreza , Rahman Mizanur , Hellwig Olav , Pisana Simone
Published: August 2018

In this work, we present the implementation of a new method to perform high-frequency thermoreflectance measurements on thin films. The so-called differential broad-band frequency domain thermoreflectance method follows broad-band frequency domain thermoreflectance developed previously [Regner et al., Rev. Sci. Instrum. 84(6), 064901 (2013)], without the use of expensive electro-optic modulators. Two techniques are introduced to recover the thermal phase of interest and to separate it from the unwanted instrumental contributions to the recorded phase. Measuring a differential thermal phase by either varying the spot size or offsetting the pump and probe beams, the thermophysical properties of materials can be extracted. This approach enables the study of nanoscale heat transport where non-equilibrium phenomena are dominating.
Evolving networks based on birth and death process regarding the scale stationarity
Authors: Feng Minyu , Deng Liangjian , Kurths Jürgen
Published: August 2018

Since the past few decades, scale-free networks have played an important role in studying the topologies of systems in the real world. From the traditional perspective, the scale of network, the number of nodes, keeps growing over time without decreasing, leading to the non-stationarity of the scale which is against the real networks. To address this issue, in this paper, we introduce both increase and decrease of vertices to build the evolving network models based on birth and death random processes which are regarded as queuing systems in mathematics. Besides the modeling, the scale of networks based on different random processes is also deduced to be stationary and denoted by a specific probabilistic expression irrelevant to time. In the simulations, we build our network models by different types of queueing systems and compare the statistical results with theories to show the validity and accuracy of our proposed models. Additionally, our model is applied to simulate and predict the populations of some developed countries in recent years.
Thermal efficiency and exergy enhancement of solar air heaters, comparative study and experimental investigation
Authors: El Ferouali Hicham , Zoukit Ahmed , Salhi Issam , El Kilali Toufiq , Doubabi Said , Abdenouri Naji
Published: August 2018

This paper links the geometric design of most classical configurations of solar air heaters (SAHs), their thermal performances, and their appropriate application. The optimization concerns mainly the absorber shape and the airflow direction. Therefore, single pass and counter flow double pass SAHs with flat plate, finned, and V-corrugated absorbers and SAH with an external recycle were investigated. The overall aim is to single out the most suitable configurations for the drying process and habitation heating. Modeling of the SAHs was based on solving the energy balance equations of the SAH's components. The numerical results showed that the thermal efficiency was significantly improved by the counter flow double pass mode by about 17.01% for SAHs with a flat plate absorber and 9.03% for SAHs with a V-corrugated absorber. Furthermore, the V-corrugated shape of the absorber increases the thermal and exergy efficiencies compared to the flat plate shape, e.g., by 8.66% and 1.27% at ṁ = 0.025 kg s−1, respectively. In addition, the present study highlighted that the outlet air temperature and the thermal and exergy efficiencies could be enhanced by increasing the number of fins, and the optimal number of fins was found to be 24 per meter width of the SAH. Experimental studies were carried on a modular SAH. They showed the good capability of the developed model in predicting the thermal performances of the studied solar collectors. Finally, the SAHs were assigned to three appropriate uses, namely, aromatic and medicinal plant drying, agri-food product drying, and habitat heating.