bluuebunny/crossref_metadata_2025 huggingface dataset:
A feasibility study of a NBI photoneutralizer based on nonlinear gating laser recirculation
Authors: Fassina A. , Pretato F. , Barbisan M. , Giudicotti L. , Pasqualotto R.
Published: November 2015

The neutralization efficiency of negative ion neutral beam injectors is a major issue for future fusion reactors. Photon neutralization might be a valid alternative to present gas neutralizers, but still with several challenges for a valid implementation. Some concepts have been presented so far but none has been validated yet. A novel photoneutralization concept is discussed here, based on an annular cavity and a duplicated frequency laser beam (recirculation injection by nonlinear gating). The choice of lithium triborate as the material for the second harmonic extractor is discussed and a possible cooling method via crystal slicing is presented; laser intensity enhancement within the cavity is evaluated in order to quantify the achievable neutralization rate. Mockups of the critical components are proposed as intermediate steps toward system realization.
Effect of magnetic field on dust charging and corresponding probe measurement
Authors: Kalita D. , Kakati B. , Saikia B. K. , Bandyopadhyay M. , Kausik S. S.
Published: November 2015

The effect of external magnetic field on the Langmuir probe measurement and dust charging are studied in low-pressure hydrogen plasma. The experiment is performed in a dusty plasma device where plasma is created by the hot cathode filament discharge technique. A strong Strontium ferrite magnet is used inside the plasma, near the dust zone. The plasma parameters are measured at different distances from the magnet with the help of Langmuir probe system. It is observed that even at “low magnetic field case,” where rLe≥rP, rLi〉〉rP; the electron collection by the probe deviates strongly from the actual value, until rLe≥10rP. The observations of electron energy probability function show that at higher magnetic field, the Langmuir probe collects only the higher energy electrons compared to the low energy electrons. Both Quasi-neutrality condition and capacitance model are used separately to calculate the charge accumulated on the dust grain. Introducing the reduction factor on quasi-neutrality condition, it is observed that the influence of magnetic field on dust charge is almost negligible for “low magnetic field” case. The dust charge calculated from quasi-neutrality condition matches well with the experimentally observed dust current results, within the experimental error range. However, capacitance model deviates from the experimental results at higher magnetic field.
Electrostatic force analysis, optical measurements, and structural characterization of zinc oxide colloidal quantum dots synthesized by sol-gel method
Authors: Choi Min S. , Meshik Xenia , Mukherjee Souvik , Farid Sidra , Doan Samuel , Covnot Leigha , Dutta Mitra , Stroscio Michael A.
Published: November 2015

ZnO quantum dots (QDs) are used in a variety of applications due to several desirable characteristics, including a wide band gap, luminescence, and biocompatibility. Wurtzite ZnO QDs also exhibit a spontaneous polarization along the growth axis, leading to large electric fields. In this work, ZnO QDs around 7 nm in diameter are synthesized using the sol-gel method. Their size and structure are confirmed using photoluminescence, Raman spectroscopy, atomic force microscopy, and transmission electron microscopy. Additionally, electrostatic force microscopy (EFM) is used to measure the amplitude change in the probe which is associated with the electric field produced by ZnO immobilized by layer-by-layer synthesis technique. The measured electrostatic field of 108 V/m is comparable to theoretically predicted value. Additionally, the strength of the electrostatic field is shown to depend on the orientation of the QD's c-axis. These results demonstrate a unique technique of quantifying ZnO's electric force using EFM.
Hot-carrier-induced linear drain current and threshold voltage degradation for thin layer silicon-on-insulator field P-channel lateral double-diffused metal-oxide-semiconductor
Authors: Zhou Xin , Qiao Ming , He Yitao , Li Zhaoji , Zhang Bo
Published: November 2015

Hot-carrier-induced linear drain current (Idlin) and threshold voltage (Vth) degradations for the thin layer SOI field p-channel lateral double-diffused MOS (pLDMOS) are investigated. Two competition degradation mechanisms are revealed and the hot-carrier conductance modulation model is proposed. In the channel, hot-hole injection induced positive oxide trapped charge and interface trap gives rise to the Vth increasing and the channel conductance (Gch) decreasing, then reduces Idlin. In the p-drift region, hot-electron injection induced negative oxide trapped charge enhances the conductance of drift doping resistance (Gd), and then increases Idlin. Consequently, the eventual Idlin degradation is controlled by the competition of the two mechanisms due to conductance modulation in the both regions. Based on the model, it is explained that the measured Idlin anomalously increases while the Vth is increasing with power law. The thin layer field pLDMOS exhibits more severe Vth instability compared with thick SOI layer structure; as a result, it should be seriously evaluated in actual application in switching circuit.
Terahertz pulsed photogenerated current in microdiodes at room temperature
Authors: Ilkov Marjan , Torfason Kristinn , Manolescu Andrei , Valfells Ágúst
Published: November 2015

Space-charge modulation of the current in a vacuum diode under photoemission leads to the formation of beamlets with time periodicity corresponding to THz frequencies. We investigate the effect of the emitter temperature and internal space-charge forces on the formation and persistence of the beamlets. We find that temperature effects are most important for beam degradation at low values of the applied electric field, whereas at higher fields, intra-beamlet space-charge forces are dominant. The current modulation is most robust when there is only one beamlet present in the diode gap at a time, corresponding to a macroscopic version of the Coulomb blockade. It is shown that a vacuum microdiode can operate quite well as a tunable THz oscillator at room temperature with an applied electric field above 10 MV/m and a diode gap of the order of 100 nm.
Unexpected features of the dark proteome
Authors: Perdigão Nelson , Heinrich Julian , Stolte Christian , Sabir Kenneth S. , Buckley Michael J. , Tabor Bruce , Signal Beth , Gloss Brian S. , Hammang Christopher J. , Rost Burkhard , Schafferhans Andrea , O’Donoghue Seán I.
Published: November 2015

Significance

A key remaining frontier in our understanding of biological systems is the “dark proteome”—that is, the regions of proteins where molecular conformation is completely unknown. We systematically surveyed these regions, finding that nearly half of the proteome in eukaryotes is dark and that, surprisingly, most of the darkness cannot be accounted for. We also found that the dark proteome has unexpected features, including an association with secretory tissues, disulfide bonding, low evolutionary conservation, and very few known interactions with other proteins. This work will help future research shed light on the remaining dark proteome, thus revealing molecular processes of life that are currently unknown.
Pentatricopeptide-repeat family protein RF6 functions with hexokinase 6 to rescue rice cytoplasmic male sterility
Authors: Huang Wenchao , Yu Changchun , Hu Jun , Wang Lili , Dan Zhiwu , Zhou Wei , He Chunlan , Zeng Yafei , Yao Guoxin , Qi Jianzhao , Zhang Zhihong , Zhu Renshan , Chen Xuefeng , Zhu Yingguo
Published: November 2015

Significance

Plant cytoplasmic male sterility (CMS) and sterility restoration by nuclear restorer-of-fertility (
Rf
) genes provide a crucial breeding tool to harness hybrid vigor in many crops. Here, we identify RF6 as a novel pentatricopeptide repeat family protein that restores the fertility of Honglian CMS (HL-CMS), a major type of rice CMS used in breeding. We demonstrated that RF6 and hexokinase 6 function together in mitochondria to promote the processing of the aberrant CMS-associated transcript
atp6-orfH79
, thereby restoring the fertility of HL-CMS rice. This study links CMS restoration to hexokinase, providing novel insights into the mechanisms of CMS restoration, pollen development, mitochondria metabolism, and nuclear-cytoplasmic communication. In addition, the present study offers opportunities to further exploit rice heterosis in hybrid rice production.
Molecular basis for specific viral RNA recognition and 2′-O-ribose methylation by the dengue virus nonstructural protein 5 (NS5)
Authors: Zhao Yongqian , Soh Tingjin Sherryl , Lim Siew Pheng , Chung Ka Yan , Swaminathan Kunchithapadam , Vasudevan Subhash G. , Shi Pei-Yong , Lescar Julien , Luo Dahai
Published: November 2015

Significance

Dengue is the most prevalent mosquito-borne viral disease, endemic in more than a hundred tropical and subtropical countries. NS5, the largest viral protein, is a key replication enzyme with both methyltransferase and RNA polymerase activities. We present to our knowledge the first crystal structure of the full-length NS5 protein from dengue virus bound to the authentic 5′-end viral RNA fragment. This structure captures the viral enzyme in the act of transferring a methyl group to the 2′-O-ribose of the first nucleotide of the viral genome, providing an atomic-level understanding of specific 2′-O-methylation and cap formation by the flavivirus methyltransferase. The structure also suggests an evolutionary origin for the methyltransferase domain of NS5 and strategies for designing novel antiviral inhibitors.
Combining Samples from Multiple Gears Helps to Avoid Fishy Growth Curves
Authors: Wilson Kyle L. , Matthias Bryan G. , Barbour Andrew B. , Ahrens Robert N. M. , Tuten Travis , Allen Micheal S.
Published: November 2015

Size-at-age information is critical in estimating growth parameters (e.g., the von Bertalanffy growth function [VBGF]) that are used to assess fish populations. Due to gear selectivity, single sampling methods rarely sample all ages or all sizes equally well. Most growth estimates rely on samples from a single gear or a haphazard combination of gears, potentially leading to biased and imprecise growth parameter estimates. We evaluated the efficacy of combining samples from two gears with different size selectivity to estimate VBGF parameters; we then applied that approach to a case study on the Lochloosa Lake (Florida) population of Black Crappies Pomoxis nigromaculatus. Simulated age- and size-structured populations were randomly sampled with two gears characterized by different size-selectivity curves (one gear was selective for smaller fish; the other was selective for larger fish). Maximum likelihood VBGF estimates obtained for each gear separately were compared with estimates from a combined VBGF fitted to data from both gears. In every simulated scenario, a combined-gear approach reduced bias and increased precision for estimating the VBGF, but the gear-specific proportions that improved VBGF estimates depended on size selectivity. The VBGF estimates for the Black Crappie population showed that the combined-gear method yielded intermediate parameter values relative to single-gear approaches based on (1) trawl sampling (fishery-independent survey) and (2) angler harvest (as determined from carcass collections; fishery-dependent data). Furthermore, the combined-gear approach had greater precision in individual parameter estimates and much less variance than single-gear approaches when estimating the VBGF. Combining data from two gears can increase sample representativeness, leading to improvements in VBGF estimation. Such approaches can reduce uncertainty in VBGF estimation and can provide insight into key demographic processes occurring in fish populations for which ontogeny and gear selectivity lead to imperfect sampling.

Received January 22, 2015; accepted July 30, 2015
Structure of propagating arc in a magneto-hydrodynamic rail plasma actuator
Authors: Gray Miles D , Choi Young-Joon , Sirohi Jayant , Raja Laxminarayan L
Published: November 2015

The spatio-temporal evolution of a magnetically driven arc in a rail plasma flow actuator has been characterized with high-speed imaging, electrical measurements, and spectroscopy. The arc draws a peak current of ~1 kA. High-speed framing cameras were used to observe the complex arc propagation phenomenon. In particular, the anode and cathode roots were observed to have different modes of transit, which resulted in distinct types of electrode degradation on the anode and cathode surfaces. Observations of the arc electrical properties and induced magnetic fields are used to explain the transit mechanism of the arc. Emission spectroscopy revealed the arc temperature and species composition as a function of transit distance of the arc. The results obtained offer significant insights into the electromagnetic properties of the arc-rail system as well as arc-surface interaction phenomena in a propagating arc.
Enhancement of minority carrier lifetimes in n- and p-type silicon wafers using silver nanoparticle layers
Authors: Thouti Eshwar , Kumar Sanjai , Komarala Vamsi K
Published: November 2015

The quasi-steady state photo conductance technique is employed to probe effective minority carrier lifetime (τ
eff) modifications after integrating silver nanoparticles (Ag NPs) on n-type and p-type silicon wafers with a native oxide surface. Our observations reveal that τ
eff modification is very sensitive to Ag NPs size, surface coverage and also wafer type. With an optimized Ag NPs, τ
eff is enhanced from 4.4 μs to 10 μs for a p-type silicon wafer, and from 8.1 μs to 14 μs for an n-type silicon wafer. We attributed the enhancement in τ
eff to the partial field effect passivation of the silicon surface by the surface plasmon resonance near-fields of Ag NPs after excitation. Our investigations demonstrate that an optimized Ag NPs on any silicon wafer with a native oxide layer can work as both a light trapping and a surface-passivating layer.
Selective growth of hierarchical ZnO nanorod arrays on the graphene nanosheets
Authors: Yang Hui , Li Lan , Li Jinliang , Mo Zhaojun
Published: November 2015

We report directly selective-area grown (SAG) high-quality hierarchical ZnO nanorod arrays on the graphene nanosheets without invoking damage or introducing a catalyst. The SAG behavior in the non-catalytic growth mechanism is attributed to dangling bonds on the boundary edges of graphene nanosheets, which serve as the preferential adsorption and nucleation sites of ZnO nanorod. High densities of hierarchical ZnO nanorods show single-crystalline hexagonal wurtzite structure and are vertically well-aligned on the graphene nanosheets, with the diameter and the density strongly dependent on the growth temperature. Furthermore, no carbon impurity can be seen in the tips of the ZnO nanorods and also no carbon-related defect peak in the 10 K PL spectrum of ZnO nanorods. Our approach using a graphene-nanosheet substrate provides an efficient route for the growth of high-quality ZnO with a one-dimensional (1D) hierarchical nanostructure, which is highly desirable for fabricating 1D ZnO hybrid optoelectronic devices, particularly for a fast-response UV photodetector and highly-sensitive gas sensor.
Distortion reduction in strong terahertz signals using broadband attenuators with flat transmittance
Authors: Peng Xiao-Yu , Teng Jinghua , Liu Hongwei , Tanoto Hendrix , Guo Hongchen , Sheng Zheng-Ming , Zhang Jie
Published: November 2015

We demonstrate numerically and experimentally a simple approach to significantly reduce the distortion of a strong terahertz (THz) pulse signal measured by the spectral-encoding technique. We propose using broadband THz attenuators with flat transmittance to attenuate the input signal to a certain low level corresponding to the strongest spectrum difference ΔI for the main negative polar. The real THz waveform can be recovered by multiplying the attenuated THz waveform by the reciprocal of the attenuation factor of the main positive polar. Using a suitable number of broadband attenuators with flat transmittance, and considering an acceptable signal-to-noise ratio, the severely distorted strong THz signal from the air plasmas induced by two-color femtosecond laser pulses was reduced significantly.
Cognition, Content, and the A Priori
Authors: Hanna Robert
Published: November 2015

This book develops a unified contemporary Kantian theory of rational human cognition and knowledge. Along the way, it provides accounts of (i) intentionality and its contents, including non-conceptual content and conceptual content, (ii) sense perception and perceptual knowledge, including perceptual self-knowledge, (iii) the analytic-synthetic distinction, (iv) the nature of logic, and (v) a priori truth and knowledge in mathematics, logic, and philosophy. This book is specifically intended to reach out to two very different audiences: contemporary Analytic philosophers of mind and knowledge, on the one hand, and contemporary Kantian philosophers or Kant-scholars, on the other. At the same time, it is also riding the crest of a wave of extremely exciting and even revolutionary emerging new trends and new work in the philosophy of mind and epistemology, with a special concentration on the philosophy of perception. What is revolutionary in this new wave are its strong emphases on action, on cognitive phenomenology, on disjunctivist direct realism, on embodiment, and on sense perception as a primitive proto-rational capacity for cognizing the world. The book makes a fundamental contribution to this philosophical revolution by giving it a specifically contemporary Kantian twist, and by pushing these new lines of investigation radically further.
Introduction
Authors: Bücheler Gebhard
Published: November 2015

This introductory chapter briefly sets out the book’s purpose, namely to offer an analytical framework to decide whether and in what legal settings tribunals should resort to the principle of proportionality. The book identifies limits to judicial balancing, and discusses other means for States to recalibrate the balance between private property rights and the public interest if they wish to do so. An overview of the subsequent chapters is also presented.
Proportionality and the FET Standard
Authors: Bücheler Gebhard
Published: November 2015

This chapter makes a case for the application of the principle of proportionality in the context of the arguably most important treaty protection in the current system of investor–State arbitration: the standard of fair and equitable treatment (FET). The chapter is organized as follows. Section I provides a brief introduction on FET, focusing on the relationship between FET and the international minimum standard of treatment and on the notion of legitimate expectations. Section II addresses the jurisprudence of the tribunals adjudicating claims arising from the 2001–3 Argentine crisis, with a particular view to the tribunals’ reasoning on the investor’s legitimate expectations and the public interest. Section III makes a case for the application of the principle of proportionality in the context of the FET standard, based on the methodology developed in Chapters 3 and 4. Section IV discusses the relationship between legitimate expectations of foreign investors and proportionality. In 2012, a tribunal ordered Ecuador to pay $1.77 billion to USA-based Occidental due to a contract termination that in the tribunal’s eyes violated the principle of proportionality. Section V analyses whether this decision could and should be understood to trigger a proportionality analysis under the FET standard whenever a State exercises its contractual rights, and Section VI concludes.
Proportionality and the Customary International Law Defence of Necessity
Authors: Bücheler Gebhard
Published: November 2015

This chapter examines the customary international law defence of necessity. Argentina argued that it experienced a state of necessity during its 2001–3 financial crisis. While all tribunals acknowledged that such a defence exists under customary international law and was accurately codified by the International Law Commission (ILC) in Article 25 of the Articles on Responsibility of States for Internationally Wrongful Acts (ASR), none of the tribunals found that Argentina could rely on it to justify its emergency measures. The chapter is organized as follows. Section I examines the applicability of Article 25 of the ASR in investor–State arbitration. Section II analyses the different elements of Article 25 and relevant jurisprudence from the Argentina cases. Section III evaluates whether arbitrators should expand the scope of necessity by applying a proportionality analysis to assess whether regulatory measures in the public interest are justified by necessity. Section IV addresses the most important issue regarding necessity for States and foreign investors alike: the consequences of a successful plea of necessity—if certain State action meets the requirements of Article 25, will the State invoking necessity have to compensate those who suffered from the exercise of this defence, and if yes, to what degree?
Summary and Concluding Remarks
Authors: Bücheler Gebhard
Published: November 2015

This chapter summarizes the main findings of this book and presents some concluding remarks. Arbitrators must bear in mind that every international investment agreement (IIA) in itself reflects a certain balance between the protection of foreign investment and other interests. When concluding IIAs, States have to weigh and balance the advantages of foreign investment and the protection of nationals abroad on one hand, with possible disadvantages of foreign investment and its protection on the other. It is not for arbitrators to undermine the balance struck in a particular IIA through a proportionality analysis. But proportionality is a valuable tool to elucidate the bargain inherent in every IIA to reconcile conflicting interests.
Agriculture as an Engine of Growth and Poverty Reduction
Authors: Gollin Douglas
Published: November 2015

This chapter reviews theories and empirical literature on the relationship between agricultural development, economic growth, and poverty reduction, focusing on sub-Saharan Africa. Data show clearly and consistently that smallholder agriculture remains a dominant source of livelihoods in Africa, with more than half of the economically active population working in that sector. Rural people also tend to be poor; although data are sparse, evidence supports the idea that poverty is concentrated in rural areas. As a result, it seems reasonable that agricultural development can play a key role in poverty reduction. But the evidence base remains sparse, and many fundamental questions remain unanswered; the chapter sets out a series of research questions that require further exploration. It is suggested that structural transformation will take place in Africa as it has in other parts of the world, largely as a process linked to economic growth.
Growth, Employment Creation, and Poverty Reduction
Authors: Bhorat Haroon
Published: November 2015

This chapter attempts to explore the role and importance of the labour market in the interactions between economic growth, poverty, and inequality. Ranging from the relationship between output and employment, through the relevant elasticities, to the estimates of labour-intensive growth in cross-country regressions, the role of the labour market in understanding growth, poverty, and inequality outcomes is assessed. An overview of current and ongoing research is provided. This is in an attempt to understand labour market dynamics of pro-poor economic growth, and linkages—not only within the economic growth–poverty nexus, but also the centrality of inequality. This is vital for creating a broader appreciation of the welfare impacts of economic growth. The chapter endeavours to suggest specific African economies where economic growth and welfare outcomes may be intermediated through the labour markets of these respective economies.
The Informal Economy, Economic Growth, and Poverty in Sub-Saharan Africa
Authors: Aryeetey Ernest
Published: November 2015

The role that informality plays in the shaping of economies is not yet very well understood. In many economies anxious to modernize and grow faster, informality is seen as a challenge that has to be tackled to move them to new levels of development. But there is little evidence that trying to induce change directly in informal economic entities benefits the larger economy in any significant way. Indeed, while the institutional economics literature provides good frameworks for understanding both the economic and socio-cultural relationships embedded in informality, the follow-through into generalized policy responses is extremely elusive. This would explain the many failed attempts to ‘formalize the informal sector’. Change must come from economic agents responding over time to changes in their environment affecting the profitability of their enterprises. Support to informal economies must be designed to improve specific conditions of operation and facilitate their evolution.
The Interaction of Focus, Givenness, and Prosody
Authors: Samek-Lodovici Vieri
Published: November 2015

This book provides an in-depth investigation of contrastive focalization in Italian, showing that its syntactic expression is systematically affected by the syntactic expression of discourse-givenness. The proposed analysis disentangles the properties genuinely associated with contrastive focalization from those determined by the most productive operations affecting discourse given phrases at the right periphery, namely right dislocation and marginalization. On this basis, it shows that in the default case contrastive focalization occurs in situ and that instances of left-peripheral focalization only arise when focus obligatorily evacuates a larger right-dislocating phrase, giving rise to a distribution of leftward-moved foci that generalizes well beyond the cases examined in Rizzi (1997) and most literature since. In its final chapter, the book examines the syntax–prosody interface, showing how focalization in situ and other key properties follow from the prosodic constraints governing stress placement, thus reinterpreting and extending Zubizarreta’s (1998) analysis of p-movement and the role of prosody in shaping syntax. Overall, this book offers an evidence-backed radical departure from current views of focalization based on a fixed focus projection at the left periphery of the clause. It also provides the most comprehensive study of Italian marginalization and right dislocation available to date.
Existentials and locatives in Romance dialects of Italy
Authors: Bentley Delia
Published: November 2015

This chapter discusses various existing definitions of existential sentence or existential construction and introduces the definition adopted in the volume. This is McNally’s (2011) definition, which is enriched with an explicit reference to the context-dependence of existentials. The chapter then outlines the principal semantic and morphosyntactic features of existential and locative there sentences in Romance, and in typological perspective, providing examples of such constructions from a wide variety of languages. It explains the scope and objectives of the volume, alongside the methodology adopted in the Manchester project on existentials, from which the volume stems. It offers a reader-friendly introduction to Role and Reference Grammar, the linguistic framework in which the analysis is couched. The acknowledgements and an outline of the volume conclude the chapter.
Historical context
Authors: Ciconte Francesco Maria
Published: November 2015

The chapter outlines the historical context in which Italo-Romance there sentences developed. Firstly, it is observed that the proform, which is absent in Latin, appears in early Italo-Romance locative there sentences with a definite focal argument. In its subsequent generalization to structures with indefinite pivots the proform is reanalysed as the proargument of existential sentences, thus losing its referential locative function. Secondly, the chapter considers existentials with the copulas habere and stare, which are attested in late Latin. Importantly, in existentials with habere the pivot does not control agreement on the copula, thus prefiguring the agreement pattern which is found in present-day habere existentials in Romance. The chapter finally turns to expletives. In Old Lombard the expletive lacks agreement features, like the expletive subject clitic found in the there sentences of many modern northern dialects. In Old Tuscan and Old Apulian the occurrence of the expletive is motivated in pragmatic or stylistic terms.
Quantum Confined Laser Devices
Authors: Blood Peter
Published: November 2015

This book looks at the fundamental optical gain and carrier recombination processes in quantum wells and quantum dots, via descriptions of common device structures to an understanding of their operating characteristics. Following a historical introduction, the text consists of five parts. Firstly, it covers the diode laser (a introductory account of the materials, structure, and operation of a laser diode). Next it looks at fundamental processes (interaction of light with an atomic dipole and quantum confinement). Thirdly, it considers device physics (gain, recombination, laser action and threshold in wells and dots). Next, it moves on to device operation (device structures, characteristics of Fabry–Perot and grating feedback devices). Finally, it looks at studies of gain and recombination (methods for measurement of gain and spontaneous recombination rate). The book gives a consistent treatment of quantum dot and well structures, taking full account of their dimensionality, which provides a complete account of contemporary quantum confined laser diodes.
The laser diode structure
Authors: Blood Peter
Published: November 2015

A laser diode structure calls for materials of different band gap to provide optical and electrical confinement and these should have a similar lattice parameter to the substrate on which they are grown. This is achieved using direct-gap compound semiconductors and their alloys in which the band gap and lattice parameter change with the composition. Typical III–V alloy systems used for laser structures are described. In some cases modest amounts of strain can give improvements in laser performance. Semiconductor alloy materials of different band gap are combined to form heterostructures, which are characterised by the band offsets at the interface between them. These materials may be the same carrier type throughout or incorporate a p–n junction to inject carriers to achieve population inversion. Construction of the energy band diagrams of these structures and of quantum wells is described.
Temperature dependence of threshold current
Authors: Blood Peter
Published: November 2015

The variation of the threshold current density with temperature is an important characteristic of a diode laser and considerable effort is devoted to designing devices that have a temperature-insensitive threshold current to avoid the expense, and power consumption, of device cooling. This chapter sets out the physics that determines this dependence, together with some illustrative examples. Relevant processes include Auger recombination and carrier leakage out of the confined region, as well as barrier recombination and current flow through the cladding layers by drift and diffusion. In quantum dot lasers the wetting layer has significant influence on the temperature dependence. In a VCSEL the temperature dependence of threshold is determined by the need to meet the threshold condition at the cavity resonance rather than the gain peak. The conditions surrounding the use of the characteristic temperature T0 as a measure of temperature sensitivity are described.
Body Mass Index, Weight Gain, and Hypertensive Disorders in
Pregnancy
Authors: Masho Saba W. , Urban Peter , Cha Susan , Ramus Ronald
Published: November 2015

BACKGROUND

This study examines the interrelationship between gestational weight gain, pre-pregnancy body mass index (BMI), race/ethnicity, and their association with hypertensive disorders during pregnancy (HDP).

METHODS

Data from the 2004–2011 national Pregnancy Risk Assessment Monitoring System (PRAMS) were analyzed. Women with singleton live births were included in the analysis ( N = 270,131). Gestational weight gain was categorized reflecting the Institute of Medicine (IOM) weight gain recommendation (no gain/weight loss; ≤11, 12–14; 15–25; 26–35; ≥36 pounds). Pre-pregnancy BMI (underweight; normal; overweight; obese) and race/ethnicity (non-Hispanic (NH) White, NH-Black, Hispanic, and NH-other) were examined. Hypertensive disorders during pregnancy were dichotomized (HDP; no HDP). Data were stratified by BMI and race/ethnicity, and multiple logistic regression analysis was conducted to generate odds ratios and 95% confidence intervals (CIs).

RESULTS

Compared to normal and overweight women who gained the IOM recommended weight, higher odds of HDP was observed in those who gained ≥36 pounds regardless of their race/ethnicity. Among obese NH-White (odds ratio (OR) = 1.29, 95% CI = 1.11, 1.50) and Hispanic women (OR = 1.64, 95% CI = 1.05, 2.54), the odds of HDP was higher among those who gained 25–35 pounds and those who gained ≥36 pounds (OR = 1.59, 95% CI = 1.37, 1.85) and (OR = 2.20, 95% CI = 1.41, 3.44), respectively. However, for NH-Black obese women, higher odds of HDP was observed among those who gained ≥36 pounds (OR = 1.34, 95% CI = 1.04, 1.73).

CONCLUSIONS

Although there are some ethnic/racial variations, pregnant women who exceeded gestational weight gain recommendations are at increased risk of HDP. Health care providers should consider the interrelationship between pre-pregnancy gestational weight gain (GWG) and BMI when counseling patients regarding HDP.
Rising drug allergy alert overrides in electronic health records: an observational retrospective study of a decade of experience
Authors: Topaz Maxim , Seger Diane L , Slight Sarah P , Goss Foster , Lai Kenneth , Wickner Paige G , Blumenthal Kimberly , Dhopeshwarkar Neil , Chang Frank , Bates David W , Zhou Li
Published: November 2015

Objective There have been growing concerns about the impact of drug allergy alerts on patient safety and provider alert fatigue. The authors aimed to explore the common drug allergy alerts over the last 10 years and the reasons why providers tend to override these alerts.

Design: Retrospective observational cross-sectional study (2004–2013).

Materials and Methods Drug allergy alert data (n = 611,192) were collected from two large academic hospitals in Boston, MA (USA).

Results Overall, the authors found an increase in the rate of drug allergy alert overrides, from 83.3% in 2004 to 87.6% in 2013 (P < .001). Alarmingly, alerts for immune mediated and life threatening reactions with definite allergen and prescribed medication matches were overridden 72.8% and 74.1% of the time, respectively. However, providers were less likely to override these alerts compared to possible (cross-sensitivity) or probable (allergen group) matches (P < .001). The most common drug allergy alerts were triggered by allergies to narcotics (48%) and other analgesics (6%), antibiotics (10%), and statins (2%). Only slightly more than one-third of the reactions (34.2%) were potentially immune mediated. Finally, more than half of the overrides reasons pointed to irrelevant alerts (i.e., patient has tolerated the medication before, 50.9%) and providers were significantly more likely to override repeated alerts (89.7%) rather than first time alerts (77.4%, P < .001).

Discussion and Conclusions These findings underline the urgent need for more efforts to provide more accurate and relevant drug allergy alerts to help reduce alert override rates and improve alert fatigue.
Risks and benefits of speech recognition for clinical documentation: a systematic review
Authors: Hodgson Tobias , Coiera Enrico
Published: November 2015

Objective To review literature assessing the impact of speech recognition (SR) on clinical documentation.

Methods Studies published prior to December 2014 reporting clinical documentation using SR were identified by searching Scopus, Compendex and Inspect, PubMed, and Google Scholar. Outcome variables analyzed included dictation and editing time, document turnaround time (TAT), SR accuracy, error rates per document, and economic benefit. Twenty-three articles met inclusion criteria from a pool of 441.

Results Most studies compared SR to dictation and transcription (DT) in radiology, and heterogeneity across studies was high. Document editing time increased using SR compared to DT in four of six studies (+1876.47% to –16.50%). Dictation time similarly increased in three of five studies (+91.60% to –25.00%). TAT consistently improved using SR compared to DT (16.41% to 82.34%); across all studies the improvement was 0.90% per year. SR accuracy was reported in ten studies (88.90% to 96.00%) and appears to improve 0.03% per year as the technology matured. Mean number of errors per report increased using SR (0.05 to 6.66) compared to DT (0.02 to 0.40). Economic benefits were poorly reported.

Conclusions SR is steadily maturing and offers some advantages for clinical documentation. However, evidence supporting the use of SR is weak, and further investigation is required to assess the impact of SR on documentation error types, rates, and clinical outcomes.
Patient-specific Immune States before Surgery Are Strong Correlates of Surgical Recovery
Authors: Fragiadakis Gabriela K. , Gaudillière Brice , Ganio Edward A. , Aghaeepour Nima , Tingle Martha , Nolan Garry P. , Angst Martin S.
Published: November 2015

AbstractAbstract

In an analysis of the same group of orthopedic surgery patients from the postoperative sample study, preoperative immune state as assessed by mass cytometry of blood samples was predictive of recovery across several domains, with toll-like receptor 4 signaling in cluster of differentiation 14+ monocytes accounted for 50% of observed variance.

Supplemental Digital Content is available in the text.

Background

Recovery after surgery is highly variable. Risk-stratifying patients based on their predicted recovery profile will afford individualized perioperative management strategies. Recently, application of mass cytometry in patients undergoing hip arthroplasty revealed strong immune correlates of surgical recovery in blood samples collected shortly after surgery. However, the ability to interrogate a patient’s immune state before surgery and predict recovery is highly desirable in perioperative medicine.

Methods

To evaluate a patient’s presurgical immune state, cell-type–specific intracellular signaling responses to ex vivo ligands (lipopolysaccharide, interleukin [IL]-6, IL-10, and IL-2/granulocyte macrophage colony-stimulating factor) were quantified by mass cytometry in presurgical blood samples. Selected ligands modulate signaling processes perturbed by surgery. Twenty-three cell surface and 11 intracellular markers were used for the phenotypic and functional characterization of major immune cell subsets. Evoked immune responses were regressed against patient-centered outcomes, contributing to protracted recovery including functional impairment, postoperative pain, and fatigue.

Results

Evoked signaling responses varied significantly and defined patient-specific presurgical immune states. Eighteen signaling responses correlated significantly with surgical recovery parameters (|R| = 0.37 to 0.70; false discovery rate < 0.01). Signaling responses downstream of the toll-like receptor 4 in cluster of differentiation (CD) 14+ monocytes were particularly strong correlates, accounting for 50% of observed variance. Immune correlates identified in presurgical blood samples mirrored correlates identified in postsurgical blood samples.

Conclusions

Convergent findings in pre- and postsurgical analyses provide validation of reported immune correlates and suggest a critical role of the toll-like receptor 4 signaling pathway in monocytes for the clinical recovery process. The comprehensive assessment of patients’ preoperative immune state is promising for predicting important recovery parameters and may lead to clinical tests using standard flow cytometry.
Cerebrospinal Fluid Biomarker for Alzheimer Disease Predicts Postoperative Cognitive Dysfunction
Authors: Evered Lisbeth , Silbert Brendan , Scott David A. , Ames David , Maruff Paul , Blennow Kaj
Published: November 2015

AbstractAbstract

There was an association between low preoperative levels of amyloid β in the cerebrospinal fluid and postoperative cognitive dysfunction (POCD) at 3 months; POCD was not observed at 12 months. Patients with Alzheimer’s disease neuropathology, identified by low cerebrospinal fluid levels of amyloid β, may be at an increased risk of POCD even in the absence of clinically detectable symptoms.

Background

Postoperative cognitive dysfunction (POCD) affects 16 to 21% of the elderly 3 months after anesthesia and surgery and is associated with adverse outcomes. The exact cause of POCD remains unknown. The authors hypothesized that elderly individuals with Alzheimer disease (AD) neuropathology, identified by cerebrospinal fluid (CSF) analysis, would have increased the risk for POCD.

Methods

CSF samples were collected from 59 patients 60 yr or older who received combined spinal and general anesthesia for elective total hip replacement. Patients underwent neuropsychological testing preoperatively and at 7 days, 3 months, and 12 months postoperatively. POCD at 3 months and cognitive decline at 12 months were calculated by using the reliable change index. CSF amyloid β1–
42 (Aβ1–
42), total-tau, phosphorylated-tau, and neurofilament light were assayed with enzyme-linked immunosorbent assay methods.

Results

POCD was identified in 5 of 57 patients (8.8%) at 3 months. For Aβ1–
42, 11 patients were below the cut-point for AD neuropathology of whom 3 were classified with POCD (27.3%; 95% CI, 6.0 to 61%), whereas of the 46 patients above the cut-point, 2 were classified with POCD (4.3%; 95% CI, 0.5 to 14.8%) (P = 0.01). There was no significant difference in the incidence of POCD in relation to the cut-points for any of the other analytes.

Conclusions

Low CSF Aβ1–
42 may be a significant predictor of POCD at 3 months. This indicates that patients with AD neuropathology even in the absence of clinically detectable AD symptoms may be susceptible to POCD.
Intraoperative Monitoring of Diaphragm Neural Pathways During Cervical Surgery by Electrical Stimulation and Recordings of Ventilator Waveforms: Physiological Bases and Pilot Study
Authors: Georgoulis George , Papagrigoriou Eirini , Pardey Bracho Gilda F. , Mertens Patrick , Sindou Marc
Published: November 2015

Background:

Surgery on the cervical spine entails the risk of damaging the neural structures responsible for diaphragmatic innervation, namely (C3)-C4-(C5) roots. In some “difficult” cases, anatomic identification of these structures may be hard to achieve. Therefore, monitoring of the diaphragm through the ventilation waveforms displayed on the anesthesia machine can be of practical help. According to literature review, very few publications have reported such monitoring.

Methods:

The present work aimed at investigating the feasibility and reliability of identifying cervical root(s) responsible for diaphragmatic innervation, by observing the changes on the recorded waveforms, indicating diaphragmatic responses to direct radicular electrical stimulation. In this study, the events not only on the capnography curve but also on pressure-time and flow-time waveforms were analyzed. Eight patients undergoing cervical Microsurgical DREZotomy (MDT) were enrolled in the study, as this surgical modality allows easy access to the C4 root, known to be prominent in diaphragmatic innervation. The technique did not require any harmful additional maneuver to the current anesthesia and surgical protocols.

Results:

Stimulation resulted in specific patterns of changes in the 3 waveforms in all 8 patients and proved “easy” to interpret, provided that close cooperation exists between the anesthesiologist and the surgeon.

Conclusion:

Intraoperative monitoring of the diaphragmatic responses to stimulation can be advocated in surgery at the cervical spine level, and also more widely in surgery in the supraclavicular region, when neural structures responsible for diaphragmatic function are at risk.
An Anatomic Study on Whether the Immature Patella is Centered on an Anteroposterior Radiograph
Authors: Kyriakedes James C. , Liu Raymond W.
Published: November 2015

Background:

In the operating room, after first obtaining a proper lateral radiograph with the condyles superimposed, a 90-degree rotation of the intraoperative fluoroscopy unit does not always produce an anteroposterior (AP) image with the patella centered. The orthogonality of these 2 views has not been well determined in children.

Methods:

This study was comprised of a radiographic group (35 knees) and a cadaveric group (59 knees). Both cadaveric and clinical images were obtained by resting or positioning the femur with the posterior condyles overlapped, and then taking an orthogonal AP image. Centering of the patella was calculated and multiple regression analysis was performed to determine the relationship between patellar centering and age, sex, ethnicity, mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle (MPTA), and contralateral centering.

Results:

Mean patellar centering, expressed as the lateral position of the patella with respect to the total condylar width, was 0.08±0.10 in the radiographic group and 0.06±0.03 in the cadaveric group. Positive (lateral) patellar centering in 1 knee had a statistically significant correlation with positive patellar centering in the contralateral knee in both the radiographs and the cadavers. In the radiographic group, there was a statistically significant correlation between femoral varus and valgus deformities and positive patellar centering. In the cadaveric group, there was a statistically significant correlation between tibial valgus and negative (medial) patellar centering.

Conclusion:

The patella in an immature knee is rarely perfectly centered on a true AP image, and is usually seated slightly laterally within the femoral condyles.

Clinical Relevance:

Obtaining a true AP intraoperative radiograph is critical to analyzing and correcting valgus and varus deformities, and in the proper placement of implants. When addressing knee deformity one should consider obtaining an AP view orthogonal either to a perfect lateral of the knee or orthogonal to the flexion axis of the knee, particularly when evaluating distal femoral deformity.