bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modulation‐Doped Field‐Effect Transistors (MODFET)
Authors: Zhu Congyong , Ferreyra Romualdo A. , Morkoç Hadis 
Published: January 2015

Conventional modulation‐doped field‐effect transistors (MODFETs) with unprecedented performance, e.g., a power gain of 15 dB at 190–235 GHz and a noise level of 1.2 dB with 7.2‐dB gain in the 90‐GHz range, have been demonstrated. Passivation process is of fundamental importance in the stability, good performance, and extension of device operative lifetime. We discuss strategies used to passivate the surface of GaAs and related compounds and GaN in the context of FETs. Recent research on the enhancement‐mode PMODFET (E‐PMODFET) variety for applications in high‐speed and low‐power digital circuits, and power amplifiers with single power supply is described. Reliability of MOSFET based on GaAs is reviewed to some extent. Scalability issues as well as progress in FinFET‐based on InGaAs channel are summarized. Also to be noted is that III–V compound semiconductors as alternative to Si as the channel material to improve the performance of metal‐oxide–semiconductor field‐effect transistors (MOSFETs) on Si platforms is a very attractive option for the next‐generation high‐speed integrated circuits but faces serious challenges because of the lack of a high‐quality and natural insulator.III‐V Nitride‐based HFETs showed tremendous performance in both high‐power RF and power‐switching applications. AlGaN/GaN based high power HFETs on SiC substrate with 60 nm gate lengths have achieved maximum oscillation frequency of 300 GHz. On‐resistance of 1.1∼1.2 Ω·mm as well as drain current of ∼0.9 A/mm was also achieved. For HFET devices operated in Class AB mode on GaN semi‐insulating substrates, a continuous wave power density of 9.4 W/mm was obtained with an associated gain of 11.6 dB and a power added efficiency of 40% at 10 GHz. III‐Nitride devices for power switching application has achieved near theoretical limit for vertical devices based GaN native substrates, and breakdown voltage as high as 1200 V and on resistance as low as 9 mΩ‐cm2 for lateral HFET devices on low‐cost silicon substrates. For AlGaN/GaN HFETs on high‐resistivity silicon substrates, promising results were also demonstrated. Because of the much larger 2DEG density in lattice‐matched InAlN/GaN HFETs, drain current as high as 2 A/mm was demonstrated, and the highest current gain cutoff frequency of 370 GHz was also reported on 7.5‐nm‐thick In In0.17Al0.83N barrier HFETs. Despite the above‐mentioned encouraging achievements, the degradation mechanisms are still not clear, which requires further investigation.The advent of high‐quality SiGe layers on Si substrates has paved the way for the exploration and exploitation of heterostructure devices in a Si environment. MODFETs based on the Si/SiGe have been achieved with extraordinaryp‐channel performance. With 0.25‐μm gate lengths, the current gain cutoff frequency is about 40 GHz. When the gate length was reduced to 0.1 μm, the current gain cutoff frequency increased to about 70 GHz.
Static Induction Transistors
Authors: Napoli Ettore , Strollo Antonio G.M. 
Published: January 2015

AbstractThe transistor, due to its capability of controlling the current flow between two terminals with a low power control on the third terminal, has revolutionized many consumer fields and opened new application areas. Such success derives from the versatility of the various transistor devices to the application niches and to the fact that transistors are manufactured using high performance semiconductor materials that guarantee low cost, reduced size, and high reliability.In the field of power electronics, the power transistors take care of managing the energy flow. As a consequence, the improvement and the optimization of power transistors results in improved power management circuits with increased efficiency, reduced environmental pollution, reduced cost, reduced size, and longer battery life. Typical application areas of the power transistors are: automotive, traction, consumer electronics, air conditioning, electric engines.The Static Induction Transistor (SIT), together with its variants, is a transistor optimized for power electronics applications that has been developed for the past fourty years, for various ranges of voltages, and using different semiconductor materials. In this entry, the history and the characteristics of the SIT are reported.
Improvement of GPS radio occultation retrieval error of E region electron density: COSMIC measurement and IRI model simulation
Authors: Wu Kang‐Hung , Su Ching‐Lun , Chu Yen‐Hsyang 
Published: January 2015

AbstractIn this article, we use the International Reference Ionosphere (IRI) model to simulate temporal and spatial distributions of global E region electron densities retrieved by the FORMOSAT‐3/COSMIC satellites by means of GPS radio occultation (RO) technique. Despite regional discrepancies in the magnitudes of the E region electron density, the IRI model simulations can, on the whole, describe the COSMIC measurements in quality and quantity. On the basis of global ionosonde network and the IRI model, the retrieval errors of the global COSMIC‐measured E region peak electron density (NmE) from July 2006 to July 2011 are examined and simulated. The COSMIC measurement and the IRI model simulation both reveal that the magnitudes of the percentage error (PE) and root mean‐square‐error (RMSE) of the relative RO retrieval errors of the NmE values are dependent on local time (LT) and geomagnetic latitude, with minimum in the early morning and at high latitudes and maximum in the afternoon and at middle latitudes. In addition, the seasonal variation of PE and RMSE values seems to be latitude dependent. After removing the IRI model‐simulated GPS RO retrieval errors from the original COSMIC measurements, the average values of the annual and monthly mean percentage errors of the RO retrieval errors of the COSMIC‐measured E region electron density are, respectively, substantially reduced by a factor of about 2.95 and 3.35, and the corresponding root‐mean‐square errors show averaged decreases of 15.6% and 15.4%, respectively. It is found that, with this process, the largest reduction in the PE and RMSE of the COSMIC‐measured NmE occurs at the equatorial anomaly latitudes 10°N–30°N in the afternoon from 14 to 18 LT, with a factor of 25 and 2, respectively. Statistics show that the residual errors that remained in the corrected COSMIC‐measured NmE vary in a range of −20% to 38%, which are comparable to or larger than the percentage errors of the IRI‐predicted NmE fluctuating in a range of −6.5% to 20%.
Estimation of triggered‐lightning dart‐stepped‐leader currents from close multiple‐station dE/dt pulse measurements
Authors: Gamerota W. R. , Uman M. A. , Hill J. D. , Ngin T. , Pilkey J. , Jordan D. M. 
Published: January 2015

AbstractThe modified transmission line model is used to derive the vertically propagating leader‐step currents necessary to radiate measured dart‐stepped‐leader dE/dt pulses from triggered lightning at close range (<400 m) and low altitude (<70 m). The model‐predicted dE/dt pulses were compared with measured dE/dt pulses at nine locations ranging from 27 to 391 m from the channel base for four dE/dt pulses radiated from two triggered dart‐stepped leaders. The dE/dt pulses at the closest station, 27 m, were unipolar, dominated by electrostatic and induction components of the radiated dE/dt, and of opposite polarity to the more distant initial dE/dt peaks. The other, more distant, eight stations exhibited bipolar dE/dt pulses, being more or less dominated by the dE/dt radiation component. The derived leader‐step current has a slow front that precedes a fast transition to peak amplitude followed by a slow decay to zero after several microseconds. For the four modeled dE/dt pulses, the estimated causative leader‐step current peak amplitudes varied from 0.9 to 1.8 kA, the half‐peak widths ranged from 370 to 560 ns, the charge transfers were about 1 mC, and the peak current derivatives were about 10 kA/µs. The upward propagation speeds of the leader‐step current were from 1.1 to 1.5 × 108 m/s with exponential spatial current decay constants from 13 to 27 m. One dE/dt pulse is analyzed in more detail by studying changes in model‐predicted waveforms versus current initiation altitude and by examining the effect of varying model input parameters.
The electron thermal structure in the dayside Martian ionosphere implied by the MGS radio occultation data
Authors: Cui J. , Galand M. , Zhang S. J. , Vigren E. , Zou H. 
Published: January 2015

AbstractWe propose a revised Chapman model for the ionosphere of Mars by allowing for vertical variation of electron temperature. An approximate energy balance between solar EUV heating and CO2 collisional cooling is applied in the dayside Martian ionosphere, analogous to the method recently proposed by Withers et al. (2014). The essence of the model is to separate the contributions of the neutral and electron thermal structures to the apparent width of the main ionospheric layer. Application of the model to the electron density profiles from the Mars Global Surveyor (MGS) radio occultation measurements reveals a clear trend of elevated electron temperature with increasing solar zenith angle (SZA). It also reveals that the characteristic length scale for the change of electron temperature with altitude decreases with increasing SZA. These observations may imply enhanced topside heat influx near the terminator, presumably an outcome of the solar wind interactions with the Martian upper atmosphere. Our analysis also reveals a tentative asymmetry in electron temperature between the northern and southern hemispheres, consistent with the scenario of elevated electron temperature within minimagnetospheres.
Ambient seismic, hydroacoustic, and flexural gravity wave noise on a tabular iceberg
Authors: MacAyeal Douglas R. , Wang Yitan , Okal Emile A. 
Published: January 2015

AbstractCross correlation of ambient seismic noise between four seismographs on tabular iceberg C16, Ross Sea, Antarctica, reveals both the source and the propagation characteristics of signals associated with icebergs. We find that noise correlation functions computed from station data are asymmetric about zero time lag, and this indicates that noise observed on the iceberg originates primarily from a compact, localized source associated with iceberg collisions between C16 and a neighboring iceberg, B15A. We additionally find two, and possibly more, distinct phases of noise propagation. We believe that flexural gravity wave propagation dominates the low‐frequency noise (>10 s period) and that hydroacoustic wave propagation in the water column between the ice and seabed appears to dominate high‐frequency noise (>10 Hz). Faster seismic propagation dominates the intermediate band (2–6 Hz); however, we do not have sufficient data to characterize the wave mechanisms more precisely, e.g., by identifying distinct longitudinal and shear body waves and/or surface waves. Secular changes in the amplitude and timing of ambient noise correlations, e.g., a diurnal cycle and an apparent shift in the noise correlation of fast seismic modes between two periods of the deployment, allow us to speculate that ambient noise correlation analysis may be helpful in understanding the sources and environmental controls on iceberg‐generated ocean noise as well as geometric properties (such as water column thickness) of subglacial lakes.
Using the Auditory Brainstem Response (ABR) to Determine Sensitivity of Hearing in Mutant Mice
Authors: Ingham Neil J. , Pearson Selina , Steel Karen P. 
Published: January 2015

AbstractMeasurements of auditory evoked potentials can be used to determine reliably an audiometric representation of hearing sensitivity in mice. In a high‐throughput phenotyping screen of mice carrying targeted mutations of single genes, the auditory brainstem response (ABR) is used to gain an estimate of hearing threshold for broadband click stimuli and pure tone frequencies ranging from 6 to 30 kHz. Comparison of thresholds obtained in mutant and wild‐type mice give a means to determine mild, moderate, and severe hearing impairment. This gives a clear advantage over using a “clickbox” test to assess hearing by observations of the Preyer reflex. The ABR screen has identified several mutant lines with mild and moderate hearing loss, which appear to demonstrate normal Preyer responses. The ABR technique also allows frequency‐selective hearing loss to be identified. Curr. Protoc. Mouse Biol. 1:279‐287 © 2011 by John Wiley & Sons, Inc.
A Comprehensive Guide to Sleeping Beauty–Based Somatic Transposon Mutagenesis in the Mouse
Authors: Moriarity Branden , Largaespada David A. 
Published: January 2015

AbstractRecent advances in whole genome analyses made possible by next‐generation DNA sequencing, high‐density array comparative genome hybridization (aCGH), and other technologies have made it apparent that cancers harbor numerous genomic changes. However, without functional correlation or validation, it has proven difficult to determine which genetic changes are necessary or sufficient to produce cancer. Thus, it is still necessary to perform unbiased functional studies using model organisms to help interpret the results of whole genome analyses of human tumors. To this end, a Sleeping Beauty (SB) transposon–based mutagenesis technology was developed to identify genes that, when mutated, can cause cancer. Herein a detailed methodology to initiate and carry out an SB transposon mutagenesis screen is described. Although this system might be used to identify genes involved with many cellular phenotypes, it has been primarily implemented for cancer. Thus, SB transposon somatic cell screens for cancer development are highlighted. Curr. Protoc. Mouse Biol. 1:347‐368 © 2011 by John Wiley & Sons, Inc.
Overexpression Models: Lentiviral Modeling of Brain Cancer
Authors: Friedmann‐Morvinski Dinorah , Singer Oded 
Published: January 2015

AbstractGlioblastoma multiforme (GBM) is one of the most common and most malignant of the brain tumors. Gliomas can be classified into four different grades according to their histologic characteristics; the most aggressive of the gliomas is glioblastoma multiforme (grade IV). Despite optimal treatment, the median survival is only 12 to 15 months. In the past few years, important advances were made in understanding the biology and pathology of malignant gliomas. A mouse model of brain tumors using inducible lentiviral vectors is described here. In this approach, a lenti‐vector with loxP sites flanking the gene of interest (oncogene) is injected into mice expressing Cre recombinase under the control of a brain‐specific promoter. The steps to perform cell‐type/region‐specific injection of Cre‐loxP‐controlled lentiviral vectors in the brain of adult mice are described here in detail. Curr. Protoc. Mouse Biol. 3:121‐139 © 2013 by John Wiley & Sons, Inc.
Clinical Chemistry and Other Laboratory Tests on Mouse Plasma or Serum
Authors: Rathkolb Birgit , Hans Wolfgang , Prehn Cornelia , Fuchs Helmut , Gailus‐Durner Valérie , Aigner Bernhard , Adamski Jerzy , Wolf Eckhard , Hrabě de Angelis Martin 
Published: January 2015

AbstractBesides hematological analyses, many other parameters, including clinical chemistry and endocrinological values, can be determined from mouse blood samples. For most of these tests, plasma or serum samples are used. Data obtained by these investigations provide indications of genotype effects on metabolism and organ functions. Here we describe in detail the considerations that have to be taken into account to get adequate samples for plasma or serum analyses and the recommended sample processing for different investigations. Furthermore, we describe established methods used in the German Mouse Clinic (GMC) to determine clinical chemical parameters; for more in‐depth analysis of specific classes of biomarkers, we provide instructions for ELISAs (sandwich and competitive) as well as LC‐MS/MS, focusing on markers associated with bone or steroid metabolism in the mouse as working examples. Curr. Protoc. Mouse Biol. 3:69‐100 © 2013 by John Wiley & Sons, Inc.
Cardiac Biomarkers in Systemic Sclerosis: Contribution of High‐Sensitivity Cardiac Troponin in Addition to N‐Terminal Pro‐Brain Natriuretic Peptide
Authors: Avouac Jérôme , Meune Christophe , Chenevier‐Gobeaux Camille , Borderie Didier , Lefevre Guillaume , Kahan André , Allanore Yannick 
Published: January 2015

ObjectiveTo measure plasma concentrations of high‐sensitivity cardiac troponin T (HS‐cTnT) and N‐terminal pro–brain natriuretic peptide (NT‐proBNP) in patients with systemic sclerosis (SSc; scleroderma) and age‐ and sex‐matched healthy control subjects, and to examine the contribution of traditional cardiovascular risk factors and SSc features to the concentrations of these 2 cardiac biomarkers.MethodsPlasma HS‐cTnT and NT‐proBNP concentrations were measured using the electrochemiluminescence method and sandwich immunoassay, respectively.ResultsThe study group comprised 161 unrelated patients with SSc and 213 matched control subjects. HS‐cTnT and NT‐proBNP plasma levels were significantly increased in SSc patients compared with controls (both P < 0.001). Similar results were observed in the subgroup of patients with SSc who had no cardiovascular risk factors (n = 72). Multivariate logistic regression analysis confirmed diabetes mellitus (P = 0.006), high blood pressure (P = 0.021), precapillary pulmonary hypertension (P = 0.039), and the diffuse cutaneous SSc (P = 0.004) as factors independently associated with an HS‐cTnT level of >14 ng/liter. Increased NT‐proBNP concentrations were associated only with the presence of precapillary pulmonary hypertension (P < 0.001). Normal concentrations of both HS‐cTnT and NT‐proBNP had a high negative predictive value for precapillary pulmonary hypertension (92%), and the combination of increased values of these 2 markers had the highest strength of association with precapillary pulmonary hypertension in logistic regression analysis.ConclusionHS‐cTnT and NT‐proBNP concentrations are increased in patients with SSc, even in those who are free of cardiovascular risk factors. These easily obtained biomarkers may be useful for systematic evaluation and stratification of SSc patients, especially to identify those at risk of pulmonary hypertension.
Footwear Experiences of People With Chronic Musculoskeletal Diseases
Authors: Hendry Gordon J. , Brenton‐Rule Angela , Barr Georgina , Rome Keith 
Published: January 2015

ObjectiveFoot pain and deformities are frequently reported by people with chronic musculoskeletal diseases, but only limited research has been conducted to explore the key issues concerning footwear difficulties in this population. The aim of this study is to explore, identify, and describe the main issues surrounding the footwear experiences of people with chronic musculoskeletal diseases.MethodsA qualitative manifest content analysis of open‐ended survey responses concerning footwear experiences was conducted from a national footwear survey of people with chronic musculoskeletal diseases in New Zealand. Eighty‐five respondents submitted usable responses. Specific statements in the text were identified as units of analysis prior to coding and organizing these units into emerging mutually exclusive categories. Content analysis was independently undertaken by 3 researchers, and the final categories and coding were achieved through consensus. Frequencies of assigned units of analysis were calculated in order to obtain a quantitative description for each category.ResultsFour categories encompassing a total of 9 subcategories related to the footwear experiences of respondents emerged from the qualitative data content analysis: difficulty finding appropriate footwear; dissatisfaction with therapeutic footwear provision and foot care access; high costs of footwear, foot care, and self‐care; and satisfaction with therapeutic footwear and foot care.ConclusionKey categories describing the important issues surrounding the footwear experiences of respondents with chronic musculoskeletal diseases were identified, which may provide important targets for improving footwear and foot care services and self‐management strategies.
Health and Utilities in Patients With Gout Under the Care of a Rheumatologist
Authors: Spaetgens B. , Tran‐Duy A. , Wijnands J. M. A. , van der Linden S. , Boonen A. 
Published: January 2015

ObjectiveTo compare limitations in health between Dutch patients with gout and the general population and to determine factors influencing societal and patient values for health as assessed with different utility approaches.MethodsA cross‐sectional study was done among 110 patients with gout under the care of a rheumatologist, with patients completing the EuroQol 5‐domain instrument (EQ‐5D), the EQ‐5D visual analog scale (EQ‐5D VAS), and the Short Form 6‐dimensions health survey (SF‐6D). Scores on EQ‐5D domains were compared with age‐ and sex‐matched general population data. Agreement between utility measures was assessed using the intraclass correlation coefficient (ICC). Mixture modeling was used to assess factors associated with the different approaches to assess utility.ResultsCompared to the general population, gout patients reported more limitations in mobility (66% versus 12%), self‐care (24% versus 8%), daily activities (49% versus 24%), and pain (76% versus 45%), but equal anxiety/depressive symptoms (18% versus 19%). For patients with gout, utilities were reduced: the mean, median, and interquartile range, respectively, were 0.74, 0.81, and 0.69–0.84 for EQ‐5D, 0.69, 0.67, and 0.59–0.81 for SF‐6D, and 66, 70, and 57–77 for EQ‐5D VAS. ICC agreement between each pair of utilities was only moderate (0.52–0.59). Only minor differences were seen in the type of variables associated with each utility approach, with worse Health Assessment Questionnaire scores, cardiovascular disease (CVD), gout concern, and gout pain consistently associated with lower utility. The strength of contribution of these variables, however, differed among the 3 approaches.ConclusionPatients with gout experience substantially impaired health compared to the general population. Although absolute values of utility varied between instruments and perspectives, functional disability, CVD, and higher gout impact contributed to utility independently of which instrument was used.
Investigating obesity among professional drivers: The high risk professional driver study
Authors: Rosso Gian Luca , Perotto Massimo , Feola Mauro , Bruno Graziella , Caramella Michele 
Published: January 2015

ObjectiveThe aim of this study is to detect the main individual and transportation factors associated with obesity and its prevalence among Italian professional drivers (PDs).MethodsWe performed a cross‐sectional questionnaire survey. Data from PDs (n = 497) were used for analyses.ResultsSixty‐one percent of participants were either overweight or obese according to their body mass index. Predictive factors for obesity were traveling more than 40,000 miles per year (odds ratio [OR] 4.20, confidence interval [CI] 1.41–12.56) and hours spent behind the wheel per day (OR 1.27, CI 1.02–1.58). Bus drivers had half the risk of being obese compared to truck drivers (OR 0.45, CI 0.23–0.87). An inverse association was detected between educational attainment and obesity (OR 0.32, CI 0.11–0.90).ConclusionsPDs with high number of driving hours per day, miles driven per year, and low educational level should be subject to special educational programs to reduce and prevent obesity. Am. J. Ind. Med. 58:212–219, 2015. © 2015 Wiley Periodicals, Inc.