bluuebunny/crossref_metadata_2025 huggingface dataset:
Classes and Missions of
UAVs
Authors: Gleason Thomas J. , Fahlstrom Paul G.
Published: May 2016

UAVs are divided into two major classes: military and civilian. These classes overlap conceptually, because there are core missions that are common to both the military and civilian world. However, almost all specific UAVs are intended for one or the other market because of the different environments in which they are required to operate. The civilian UAV market is further divided between some commercial and government applications that required relatively large and expensive UAVs and a rapidly growing market for small and inexpensive UAVs that have been applied to an equally rapidly growing list of applications. Classes and missions of unmanned aerial vehicles (UAVs) are discussed in terms of both various official systems of classification developed by government agencies and informal classifications by size and/or primary markets. These discussions are illustrated by representative examples.
Relative Navigation in GPS‐Degraded Environments
Authors: Wheeler David O. , Nyholm Paul W. , Koch Daniel P. , Ellingson Gary J. , McLain Timothy W. , Beard Randal W.
Published: May 2016

For unmanned aircraft systems to become fully integrated into society, safe and reliable methods for estimation and control are required even when global measurements such as GPS are degraded or unavailable. In these situations, estimating the vehicle's global state directly leads to inaccuracy and inconsistency. The relative navigation framework avoids these issues by estimating the vehicle's state with respect to a current local coordinate frame associated with a visual odometry algorithm. A globally consistent and localized pose‐graph map is produced by compounding these local estimates and opportunistically incorporating additional constraints such as GPS measurements and loop closures. This architecture increases the safety and performance of the system by decoupling critical tasks, such as stabilization and obstacle avoidance, from tasks such as global map optimization and mission planning that are more computationally intensive and can produce discontinuities. The architecture and components of the general relative navigation framework are described, and hardware results are presented for an example multirotor implementation.
Recovery of
UAVs
Authors: Gleason Thomas J. , Fahlstrom Paul G.
Published: May 2016

Recovery of an unmanned aerial vehicle (UAV) may utilize a remote‐controlled or automated landing on a runway, sometimes using arresting gear to limit the landing run‐out, or an automated arrested landing on an aircraft carrier. Small UAVs can be flown into the ground at a low rate of decent and allowed to slide to a stop. For mid‐air recovery, the UAV deploys a parachute or parfoil and a large manned aircraft snags the parachute/parafoil with a hook and winches in the UAV. So‐called “zero‐length recovery” is accomplished by flying a fixed‐wing UAV into a vertical net. UAVs capable of vertical landing can be landed under remote manual or automated control on any reasonably level surface. Shipboard recovery has been implemented with vertical nets and with a combination of a parafoil and snagging by the ship followed by winching the UAV down to a landing pad, with many special requirements to deal with the possibility that the landing pad on the ship may be moving rapidly in an irregular manner, including violent pitch and roll motion. Each of these approaches has different requirements and some, such as vertical nets, impose significant restrictions on the basic configuration of the air vehicle.
Electric Drives for Propulsion System of Transport Aircraft
Authors: Pornet Clément
Published: May 2016

Following the hybridization or complete electrification strategy of the electric drive pursued on terrestrial vehicles, the aviation industry is considering with great attention the application of electrical technology and power electronics for transport aircraft. The growing interest toward electric application in transport aircraft is driven by the ambitious targets for aviation declared by Europe and by the United States of America and is motivated by the growing evidence that evolutionary improvement of the technologies might not be sufficient to fulfill these targets. As a result, the introduction of disruptive technologies turns out to be essential. With respect to the progress and perspective in electrical technology, electric drive applications to transport aircraft reveals itself to be a promising field in view of meeting the future goals.

The focus of this chapter is the assessment of the electrification of the propulsion system of transport aircraft. While aiming for the ultimate goal of universally electric aircraft, hybrid electric approach will be first necessary to match the requirement of aircraft propulsion system and the development pace of the electrical components technology. The combinatorial variety of hybrid electric and universally electric propulsion system topology considered for transport aircraft application as well as key enabling technologies are first reviewed. A compendium of hybrid electric and universally electric advanced aircraft concepts is then proposed to obtain a notion of the cloud of aircraft configurations and electric drive options investigated up to this point in time. Finally, the integrated prospects of hybrid electric aircraft are investigated to establish the feasibility of hybrid electric aircraft for future market segments.
Lithium‐Ion Batteries: Thermomechanics, Performance, and Design Optimization
Authors: Xue Nansi , Du Wenbo , Martins Joaquim R.R.A , Shyy Wei
Published: May 2016

Lithium‐ion batteries have attracted considerable academic and commercial interest due to their higher energy and power density relative to other rechargeable electrochemical systems. Recently, they have been used to power an increasing range of appliances, ranging from implantable medical devices to electric vehicles. Since the commercialization of lithium‐ion batteries by Sony in 1991, there has been an increasing amount of research carried out to further improve their energy density, life cycle, and thermal management. In addition to experimental studies, numerical models have offered new insights into physical phenomena and processes occurring in the cell, and have supported the design optimization of cells and modules. However, given the multiscale and multiphase nature of a cell, the detailed modeling of every aspect of the cell has been difficult to achieve. While thermomechanical issues play a key role in battery design, the importance of broader issues related to cell degradation, safety, manufacturing, and battery management cannot be ignored. As the achievable performance edges closer to the theoretical limits, further gains have to come from major changes, such as new electrode materials, new cell architectures, or transitioning from intercalation to conversion chemistry. Proper consideration of the wide variety of issues that impact battery performance is needed to support further investigation to meet these challenges.
Aircraft Noise: Alleviating Constraints to Airport Operations and Growth
Authors: Hooper Paul D. , Thomas Callum S. , Hume Ken I. , Maughan Janet A.
Published: May 2016

Despite substantial improvements in aircraft noise technology and operational practices, the disturbance caused by aircraft noise in communities surrounding airports remains a critical threat to aviation growth. Aircraft noise affects sleep and health and interferes with relaxation, speech, and cognitive performance. Investigation of noise complaints reveals that there are also a number of nonacoustic issues, such as the attitudes to the airport, that exacerbate the response of local residents to noise events. Community disturbance gives rise to opposition, which can lead to operational restrictions and airport growth constraints. Environmental regulations generally seek to limit the number of people affected by aircraft noise, and technological and operational improvements over the last few decades have contributed positively to this outcome. However, more recently, these improvements have been offset by traffic growth, making such regulatory targets increasingly difficult to achieve, especially where poor land‐use planning has allowed urban encroachment upon airports. At the same time, attitudes are changing, so that levels of noise considered acceptable in the past will no longer be considered so in the future. As a result, airports face a significant challenge to minimize noise and maximize tolerance among their neighbors if they are to continue to grow and thereby contribute to economic prosperity while constraining any negative consequences to socially acceptable levels.
Socioecological correlates of clinical signs in two communities of wild chimpanzees (Pan troglodytes) at Gombe National Park, Tanzania
Authors: Lonsdorf Elizabeth V. , Gillespie Thomas R. , Wolf Tiffany M. , Lipende Iddi , Raphael Jane , Bakuza Jared , Murray Carson M. , Wilson Michael L. , Kamenya Shadrack , Mjungu Deus , Collins D. Anthony , Gilby Ian C. , Stanton Margaret A. , Terio Karen A. , Barbian Hannah J. , Li Yingying , Ramirez Miguel , Krupnick Alexander , Seidl Emily , Goodall Jane , Hahn Beatrice H. , Pusey Anne E. , Travis Dominic A.
Published: May 2016

Disease and other health hazards pose serious threats to the persistence of wild ape populations. The total chimpanzee population at Gombe National Park, Tanzania, has declined from an estimated 120 to 150 individuals in the 1960's to around 100 individuals by the end of 2013, with death associated with observable signs of disease as the leading cause of mortality. In 2004, we began a non‐invasive health‐monitoring program in the two habituated communities in the park (Kasekela and Mitumba) with the aim of understanding the prevalence of health issues in the population, and identifying the presence and impacts of various pathogens. Here we present prospectively collected data on clinical signs (observable changes in health) in the chimpanzees of the Kasekela (n = 81) and Mitumba (n = 32) communities over an 8‐year period (2005–2012). First, we take a population approach and analyze prevalence of clinical signs in five different categories: gastrointestinal system (diarrhea), body condition (estimated weight loss), respiratory system (coughing, sneezing etc.), wounds/lameness, and dermatologic issues by year, month, and community membership. Mean monthly prevalence of each clinical sign per community varied, but typically affected <10% of observed individuals. Secondly, we analyze the presence of clinical signs in these categories as they relate to individual demographic and social factors (age, sex, and dominance rank) and simian immunodeficiency virus (SIVcpz) infection status. Adults have higher odds of being observed with diarrhea, loss of body condition, and wounds or lameness when compared to immatures, while males have a higher probability of being observed with wounds or lameness than females. In contrast, signs of respiratory illness appear not to be related to chimpanzee‐specific factors and skin abnormalities are very rare. For a subset of known‐rank individuals, dominance rank predicts the probability of wounding/lameness in adult males, but does not predict any adverse clinical signs in adult females. Instead, adult females with SIVcpz infection are more likely to be observed with diarrhea, a finding that warrants further investigation. Comparable data are needed from other sites to determine whether the prevalence of clinical signs we observe are relatively high or low, as well as to more fully understand the factors influencing health of wild apes at both the population and individual level. Am. J. Primatol. 80:e22562, 2018. © 2016 Wiley Periodicals, Inc.
Metabolic evolution and 13C flux analysis of a succinate dehydrogenase deficient strain of Yarrowia lipolytica
Authors: Yuzbashev Tigran V. , Bondarenko Pavel Yu. , Sobolevskaya Tatiana I. , Yuzbasheva Evgeniya Yu. , Laptev Ivan A. , Kachala Vadim V. , Fedorov Alexander S. , Vybornaya Tatiana V. , Larina Anna S. , Sineoky Sergey P.
Published: May 2016

Bio‐based succinic acid production can redirect industrial chemistry processes from using limited hydrocarbons to renewable carbohydrates. A fermentation process that does not require pH‐titrating agents will be advantageous to the industry. Previously, a Yarrowia lipolytica strain that was defective for succinate dehydrogenase was constructed and was found to accumulate up to 17.5 g L−1 of succinic acid when grown on glycerol without buffering. Here, a derivative mutant was isolated that produced 40.5 g L−1 of succinic acid in 36 h with a yield of 0.32 g g−1 glycerol. A combination approach of induced mutagenesis and metabolic evolution allowed isolation of another derivative that could utilize glucose efficiently and accumulated 50.2 g L−1 succinic acid in 54 h with a yield of 0.43 g g−1. The parent strain of these isolated mutants was used for [1,6‐13C2]glucose assimilation analysis. At least 35% glucose was estimated to be utilized through the pentose phosphate pathway, while ≥84% succinic acid was formed through the oxidative branch of the tricarboxylic acid cycle. Biotechnol. Bioeng. 2016;113: 2425–2432. © 2016 Wiley Periodicals, Inc.
Cell migration and organization in three‐dimensional in vitro culture driven by stiffness gradient
Authors: Joaquin Danielle , Grigola Michael , Kwon Gubeum , Blasius Christopher , Han Yutao , Perlitz Daniel , Jiang Jing , Ziegler Yvonne , Nardulli Ann , Hsia K. Jimmy
Published: May 2016

Durotaxis, a phenomenon that cells move according to changes in stiffness of the extra cellular matrix, has emerged as a crucial parameter controlling cell migration behavior. The current study provides a simple method to generate three‐dimensional continuous stiffness variations without changing other physical characteristics of the extra cellular environment. Using Finite Element simulations, the stiffness and the stiffness gradient variations are evaluated quantitatively, leading to an analysis of the dependence of cell migration behavior on the substrate stiffness parameters. We tested various cell lines on several 3‐D environments. The durotaxis results show that the cell migration velocity does not have any consistency with the stiffness of the substrate, rather it is more related to the stiffness gradient of the substrate. This finding suggests a new mechanism underlying the durotaxis phenomenon, highlighting the importance of the substrate stiffness gradient, rather than the stiffness itself. Biotechnol. Bioeng. 2016;113: 2496–2506. © 2016 Wiley Periodicals, Inc.
Long‐term soy consumption and tumor tissue MicroRNA and gene expression in triple‐negative breast cancer
Authors: Guo Xingyi , Cai Qiuyin , Bao Pingping , Wu Jie , Wen Wanqing , Ye Fei , Zheng Wei , Zheng Ying , Shu Xiao‐Ou
Published: May 2016

BACKGROUND

Soy food intake may have protective effects against the risk for breast cancer, including estrogen receptor (ER)–negative breast cancer. However, the underlying molecular mechanisms remain unclear.

METHODS

To evaluate the association of soy intake with the expression of microRNAs (miRNAs) and genes in the tumor tissue of patients with triple‐negative breast cancer (TNBC; ie, breast cancer lacking expression of ER, progesterone receptor, and human epidermal growth factor receptor 2), the expression of 800 miRNAs and 302 genes were measured with NanoString nCounter assays in formalin‐fixed, paraffin‐embedded tumor tissue from 272 TNBC patients. Soy intake during the 1‐year period before the cancer diagnosis was assessed with a validated food‐frequency questionnaire. The association of soy intake with the expression of miRNAs and genes was evaluated via linear regression analysis with adjustments for patient age and TNM stage.

RESULTS

A total of 14 miRNAs and 24 genes were significantly associated with soy food intake (P < .05): Thirteen of the 14 miRNAs (92.9%) and 9 of the 24 genes (37.5%), including tumor suppressors miR‐29a‐3p and IGF1R, showed overexpression for those women with high soy intake, whereas the remaining miRNAs and genes, including oncogenes KRAS and FGFR4, showed underexpression. Furthermore, cell growth–related genes showed a predominantly underexpression pattern according to a comparison of tumor samples from women with high soy food intake and samples from women with lower soy food intake.

CONCLUSIONS

This study suggests that long‐term prediagnosis soy intake may lead to increased expression of tumor suppressors and decreased expression of oncogenes, especially cell growth–related genes, in breast tumor tissues. Cancer 2016;122:2544–51. © 2016 American Cancer Society.
Influence of the treatment facility volume on the survival of patients with non‐Hodgkin lymphoma
Authors: Go Ronald S. , Al‐Hamadani Mohammed , Shah Nilay D. , Crowson Cynthia S. , Holton Sara J. , Habermann Elizabeth B.
Published: May 2016

BACKGROUND

Prior studies have shown that a higher hospital volume or physician caseload is associated with better outcomes for complex and uncommon surgical procedures. Similar studies in the medical management of rare diseases such as hematologic cancers are limited. This retrospective, observational study using the US National Cancer Data Base determined the extent to which the number of new non‐Hodgkin lymphoma (NHL) patients treated annually at a treatment facility affected overall survival (OS).

METHODS

There were 278,985 patients treated at 1151 facilities from 1998 to 2006. Treatment facilities were classified by quartiles based on the average number of new NHL patients seen annually: quartile 1 (Q1), 2 to 13 patients; quartile 2 (Q2), 14 to 20 patients; quartile 3 (Q3), 21 to 32 patients; and quartile 4 (Q4), 33 or more patients. The outcome of interest was OS according to facility volume.

RESULTS

The unadjusted median OS was 61.8 months for Q1, 65.9 months for Q2, 71.4 months for Q3, and 83.6 months for Q4. A multivariate analysis that was adjusted for demographic (sex, age, race, and ethnicity), socioeconomic (income and insurance type), geographic (area of residence), disease‐specific (NHL subtype and stage), and facility‐specific factors (type and location) showed that the facility volume was associated with OS. Compared with patients at Q4 facilities, patients at lower quartile facilities had higher mortality (hazard ratio for Q3, 1.05 [95% confidence interval, 1.04‐1.06]; hazard ratio for Q2, 1.08 [95% confidence interval, 1.07‐1.10]; hazard ratio for Q1, 1.14 [95% confidence interval, 1.11‐1.17]).

CONCLUSIONS

NHL patients treated at higher volume facilities may survive longer than those treated at lower volume facilities. Further work is needed to understand the mechanisms of these differences and whether volume should be considered in the determination of referrals for NHL patients. Cancer 2016;122:2552–9. © 2016 American Cancer Society.
The role of 5‐aminolevulinic acid in enhancing surgery for high‐grade glioma, its current boundaries, and future perspectives: A systematic review
Authors: Mansouri Alireza , Mansouri Sheila , Hachem Laureen D. , Klironomos George , Vogelbaum Michael A. , Bernstein Mark , Zadeh Gelareh
Published: May 2016

5‐Aminolevulinic acid (5‐ALA) has been approved as an intraoperative adjunct in glioma surgery in Europe, but not North America. A systematic review was conducted to assess the evidence regarding 5‐ALA as a surgical adjunct. The MEDLINE, EMBASE, and CENTRAL databases were searched, using terms relevant to “5‐ALA” and “high‐grade gliomas.” Included studies were based on adults aged ≥18 years who underwent surgical resection/biopsy. No language or date limitations were used. Forty‐three studies (1830 patients) were identified. Thirty‐six were coordinated by European countries, 2 were in the United States, and none were in Canada. One was randomized, 28 were prospective, and 14 were retrospective. Twenty‐six studies assessed the utility of 5‐ALA as a diagnostic tool, 24 assessed its influence on the extent of resection (EOR), 9 assessed survival, and 22 reported adverse events. 5‐ALA had high sensitivity and positive predictive value, whereas its specificity increased with additional adjuncts. The EOR increased with 5‐ALA, but only progression‐free survival was significantly influenced. Reporting of adverse events was not systematic. The use of 5‐ALA improved tumor visualization and thus enabled a greater EOR and perhaps increased survival. However, additional adjuncts may be necessary for maximizing the specificity of resection and patient safety. Additional parameters, such as patient quality of life and health economic analyses, would be informative. Thus, additional systematic collection of prospective evidence may be necessary for the global incorporation of this potentially valuable surgical adjunct into routine practice. Cancer 2016;122:2469–78. © 2016 American Cancer Society.
HPV vaccination in Southern Africa: A jab of hope in the fight against cervical cancer
Authors: Michelow Pamela , Firnhaber Cynthia
Published: May 2016

Cervical cancer is one of the most common causes of cancer‐related deaths in Southern Africa. Human papillomavirus vaccination offers a chance to markedly reduce this burden of disease, although challenges with vaccine delivery need to be overcome.
Multiplexed imaging of intracellular protein networks
Authors: Grecco Hernán E. , Imtiaz Sarah , Zamir Eli
Published: May 2016

Cellular functions emerge from the collective action of a large number of different proteins. Understanding how these protein networks operate requires monitoring their components in intact cells. Due to intercellular and intracellular molecular variability, it is important to monitor simultaneously multiple components at high spatiotemporal resolution. However, inherent trade‐offs narrow the boundaries of achievable multiplexed imaging. Pushing these boundaries is essential for a better understanding of cellular processes. Here the motivations, challenges and approaches for multiplexed imaging of intracellular protein networks are discussed. © 2016 International Society for Advancement of Cytometry
Organic carbon inputs, common ions and degassing: rethinking mixing dissolution in coastal eogenetic carbonate aquifers
Authors: Gulley Jason D. , B.Martin Jonathan , Brown Amy
Published: May 2016

Caves deliver freshwater from coastal carbonate landscapes to estuaries but how these caves form and grow remains poorly understood. Models suggest fresh and salt water mixing drives dissolution in eogenetic limestone, but have rarely been validated through sampling of mixing waters. Here we assess controls on carbonate mineral saturation states using new and legacy geochemical data that were collected in vertical profiles through three cenotes and one borehole in the Yucatan Peninsula. Results suggest saturation states are primarily controlled by carbon fluxes rather than mixing. Undersaturation predicted by mixing models that rely on idealized end members is diminished or eliminated when end members are collected from above and below actual mixing zones. Undersaturation due to mixing is limited by CO2 degassing from fresh water in karst windows, which results in calcite supersaturation. With respect to saline groundwater, controls on capacity for mixing dissolution were more varied. Oxidation of organic carbon increased pCO2 of saline groundwater in caves (pCO2 = 10–2.06 to 10–0.96 atm) relative to matrix porosity (10–2.39 atm) and local seawater (10–3.12 atm). The impact of increased pCO2 on saturation state, however, depended on the geochemical composition of the saline water and the magnitude of organic carbon oxidation. Carbonate undersaturation due to mixing was limited where gypsum dissolution (Cenote Angelita) or sulfate reduction (Cenote Calica) increased concentrations of common ions (Ca2+ or HCO3−, respectively). Maximum undersaturation was found to occur in mixtures including saline water that had ion concentrations and ratios similar to seawater, but with moderately elevated pCO2 (Cenote Eden). Undersaturation, however, was dominated by the initial undersaturation of the saline end member, mixing was irrelevant. Our results add to a growing body of literature that suggests oxidation of organic carbon, and not mixing dissolution, is the dominant control on cave formation and enlargement in coastal eogenetic karst aquifers. Copyright © 2016 John Wiley & Sons, Ltd.
Comparison and evaluation of pesticide monitoring programs using a process-based mixture model
Authors: Baas Jan , Vijver Martina , Rambohul Justin , Dunbar Mike , van 't Zelfde Maarten , Svendsen Claus , Spurgeon Dave
Published: May 2016

A number of European countries run large-scale pesticide monitoring schemes in watersheds aimed at identifying and evaluating the presence of pesticide residues in the environment. These schemes provide national and regional scale assessments of pesticide concentrations within the context of environmental quality assessment, aiming to ensure some degree of ecological protection. The present study is aimed at evaluating the joint effects of the pesticide mixtures detected in monitoring programs, using a process-based mixture model that was parameterized for Daphnia magna. In total, over 15 000 samples containing over 1 million individual measurements were evaluated for effects. It was found that there are only a small number of places where one can expect to have effects on daphnids, based on measured concentrations. The most polluted samples would cause extinction of a daphnid population within only 30 h. The results show that effects are mostly triggered by a limited number of pesticide residues at locations with high emissions. It was also shown that the analytical detection limits are basically too high to exclude mixture effects. So, despite all the effort that is put into chemical monitoring programs, it remains a challenge to make statements on whether or not the environment is protected. Recommendations are offered for a different setup of monitoring programs to improve this situation. Environ Toxicol Chem 2016;35:3113–3123. © 2016 SETAC
A Study of the Use of the TOEFL iBT® Test Speaking and Listening Scores for International Teaching Assistant Screening
Authors: Wagner Elvis
Published: May 2016

Although the speaking section of the TOEFL iBT® test is used by many universities to determine if international teaching assistants (ITAs) have the oral proficiency necessary to be classroom instructors, relatively few studies have investigated the validity of using TOEFL iBT scores for ITA screening. The primary purpose of this study was to determine the effectiveness of using TOEFL iBT Speaking and Listening scores for ITAs in the context of an urban research university. This was accomplished by correlating the TOEFL iBT test scores with the scores obtained by prospective ITAs on local screening tests and student evaluations of ITAs' language and teaching competence and by using the TOEFL iBT test scores as predictors of ITA teaching performance as measured by student evaluations. Given that listening comprehension is an important aspect of instructional language competence, both TOEFL iBT Speaking and TOEFL iBT Listening scores were used as predictors. The development of ITAs' oral proficiency over a semester in an English‐speaking environment was also examined by comparing their TOEFL iBT Speaking and Listening scores at the beginning and at the end of their first semester as ITAs. The results indicate that TOEFL iBT Speaking and Listening scores correlate moderately with the local screening exam, but more importantly, the results indicate that TOEFL iBT Listening might be a better predictor of teaching competence. Although TOEFL iBT Speaking scores did not correlate with or predict the various measures of teaching competence, TOEFL iBT Listening scores did. In addition, the study found that ITAs living and teaching in an English‐speaking environment did make measurable gains in oral proficiency over the course of a 3‐month period. Although these gains were relatively small, and the listening score gains were not statistically significant, this is the first study that has actually tried to measure the improvement in ITAs' oral proficiency while living and studying (and sometimes teaching) on campus. The importance of this study goes beyond the local context. This is the first study to examine the relationship between TOEFL iBT Speaking and Listening scores and instructional performance of ITAs, thus serving as a validation study of the use of the TOEFL iBT test for ITA placement purposes. The study also offers insights into ITAs' development of oral proficiency once they are in an English‐speaking environment, which can serve as a basis for future ITA curriculum development.
Dimensionality Analyses of the GRE® revised General Test Verbal and Quantitative Measures
Authors: Robin Frédéric , Bejar Isaac , Liang Longjuan , Rijmen Frank
Published: May 2016

Exploratory and confirmatory factor analyses of domestic data from the GRE® revised General Test, introduced in 2011, were conducted separately for the verbal (VBL) and quantitative (QNT) reasoning measures to evaluate the unidimensionality and local independence assumptions required by item response theory (IRT). Results based on data from the period immediately after the launch of the revised test and data from a year later showed that very little local item dependence was present and that a predominant single factor accounted for each of the data sets. These results provide evidence supporting the assumptions that underlie the use of the unidimensional 2‐parameter IRT model for scoring and contribute evidence for the validity of GRE scores and their use.
Groove model of tibia‐femoral osteoarthritis in the rat
Authors: de Visser Huub M. , Weinans Harrie , Coeleveld Katja , van Rijen Mattie H. P. , Lafeber Floris P. J. G. , Mastbergen Simon C.
Published: May 2016

Several experimental models of osteoarthritis in rats are used to study the pathophysiology of osteoarthritis. Many mechanically induced models have the limitation that permanent joint instability is induced by, for example, ligament transection or meniscal damage. This permanent instability will counteract the potential beneficial effects of therapy. The groove model of osteoarthritis uses a one‐time trigger, surgically induced cartilage damage on the femoral condyles, and has been validated for the canine tibia‐femoral compartment. The present study evaluates this model for the rat knee joint. The articular cartilage of the weight bearing surface of both femoral condyles and trochlea were damaged (grooved) without damaging the underlying subchondral bone. Severity of joint degeneration was histologically assessed, in addition to patella cartilage damage, and subchondral bone characteristics by means of (contrast‐enhanced) micro‐CT. Mild histological degeneration of the surgically untouched tibial plateau cartilage was observed in addition to damage of the femoral condyles, without clear synovial tissue inflammation. Contrast enhanced micro‐CT demonstrated proteoglycan loss of the surgically untouched patella cartilage. Besides, a more sclerotic structure of the subchondral bone was observed. The tibia‐femoral groove model in a rat results in mild knee joint degeneration, without permanent joint instability and joint inflammation. This makes the rat groove model a useful model to study the onset and progression of post‐traumatic non‐inflammatory osteoarthritis, creating a relatively sensitive model to study disease modifying osteoarthritic drugs. © 2016 The Authors. Journal of Orthopaedic Research published by Wiley Periodicals, Inc. on behalf of the Orthopaedic Research Society. J Orthop Res 35:496–505, 2017.
Screening of the COL2A1 mutation in idiopathic osteonecrosis of the femoral head
Authors: Sakamoto Yuma , Yamamoto Takuaki , Miyake Noriko , Matsumoto Naomichi , Iida Aritoshi , Nakashima Yasuharu ,   Research Committee on Idiopathic Osteonecrosis of the Femoral Head of the Ministry of Health, Labour and Welfare of Japan, Iwamoto Yukihide , Ikegawa Shiro
Published: May 2016

Idiopathic osteonecrosis of the femoral head (idiopathic ONFH) is an ischemic disorder resulting in necrosis of the subchondral bone of the femoral head. COL2A1 mutations, including c.3508G>A, have been reported to be involved in its etiology. However, the etiological role of COL2A1 mutations in idiopathic ONFH remains controversial, because the pathology of idiopathic ONFH is ischemic necrosis, not epiphyseal dysplasia usually seen in the diseases caused by COL2A1 mutations. The purpose of this study is to examine whether COL2A1 mutations have causal relation with idiopathic ONFH or not. We recruited 1,451 Japanese patients with idiopathic ONFH, including steroid‐, alcohol‐, and neither steroid nor alcohol‐associated (neither‐associated) ONFH. The diagnosis was based on the criteria of the Japanese Research Committee on idiopathic ONFH of the Ministry of Health, Labour and Welfare. By whole‐exome sequencing, entire COL2A1 coding regions and flanking introns were analyzed in 49 neither‐associated ONFH patients. In addition, the c.3508G>A mutation of COL2A1 was checked in all idiopathic ONFH patients using the invader assay. Whole‐exome sequencing did not detect any COL2A1 mutations in the 49 patients. The c.3508G>A mutation was not found in any of the 1,451 patients. In conclusion, COL2A1 is unlikely to cause idiopathic ONFH. Epiphyseal dysplasia of the femoral head caused by COL2A1 mutations may radiographically mimic idiopathic ONFH. COL2A1 mutations should prompt clinical re‐evaluation of the patient's phenotype. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:768–774, 2017.
A patient-preference cohort study of office versus inpatient uterine polyp treatment for abnormal uterine bleeding
Authors: Cooper Natalie A. M. , Middleton Lee , Smith Paul , Denny Elaine , Stobert Lynda , Daniels Jane , Clark T. Justin ,   on behalf of the OPT trial collaborative group
Published: May 2016

Uterine polyps can cause abnormal bleeding in women. Conventional practise is to remove them under general anaesthesia but advances in technology have made it possible to perform polypectomy in the office setting. We conducted a patient-preference study to explore women’s preferences for treatment setting and to evaluate the effectiveness and treatment experience of women undergoing uterine polypectomy. Three hundred ninety-nine women with abnormal uterine bleeding who were found to have uterine polyps at diagnostic hysteroscopy were recruited. Office polypectomies were performed in office hysteroscopy clinics, and inpatient procedures were undertaken in operating theatres. Three hundred twenty-four of 399 (81 %) expressed a preference for office treatment. There was no difference found between office treatment and inpatient treatment in terms of alleviating abnormal uterine bleeding as assessed by patients and in improving disease-specific quality of life. Acceptability was lower and patient pain scores were significantly higher in the office group. When offered a choice of treatment setting for uterine polypectomy, patients have a preference for office over inpatient treatment. Ambulatory gynaecology services should be available within healthcare systems to meet patient demand.
How do Physicians Decide to Refer Their Patients for Psychiatric Genetic Counseling? A Qualitative Study of Physicians’ Practice
Authors: Leach Emma , Morris Emily , White Hannah J. , Inglis Angela , Lehman Anna , Austin Jehannine
Published: May 2016

Psychiatric genetic counseling (PGC) is an emerging specialty discipline within the genetic counseling profession. A specialist PGC service was founded in 2012 in Vancouver, Canada, and though patient benefits have been demonstrated, many physicians do not regularly refer patients to the service despite awareness of its availability. We conducted a qualitative study involving semi‐structured telephone interviews with Vancouver‐based physicians who were aware of the PGC service to explore this phenomenon. Interviews were audio‐recorded, transcribed verbatim, coded, and analysed for emergent themes. Consistent with a grounded theory approach, constant comparison was employed throughout data collection and analysis. Analyses of interviews conducted with 12 physicians revealed that referral practices were informed by perceptions about the purpose of PGC and interpretation of patient cues. Physicians perceived PGC as an information‐focused intervention, and considered referral when patients explicitly expressed desire for information about recurrence risk or etiology that they felt unable to adequately address themselves. Even when physicians identified psychotherapeutic benefits of PGC, patient needs of this nature were not perceived as cues prompting referral to PGC. These data suggest that further work is necessary to position PGC in physicians’ minds as a service that could potentially benefit most individuals with psychiatric disorders and their families, and that it encompasses more than information provision. It is important to increase physicians’ awareness of the complementary role that genetic counselors can play to that of the physician in providing psychotherapeutically oriented counselling about illness etiology.
Temperature analysis of a pin-on-disc tribology test using experimental and numerical approaches
Authors: Abdullah Oday I. , Schlattmann Josef
Published: May 2016

The high thermal stresses generated at the interface between the contacting surfaces due to the sliding between parts of sliding system such as friction clutches and brakes. In this work, pin-on-disc test rig was built to find the temperature field during the sliding operation using experimental and numerical approaches. In the experimental approach, infrared camera was used to find the temperature distribution, while in the numerical approach a finite element technique has been used. Analysis has been completed using three-dimensional model to simulate a pin-on-disc system. The numerical results have shown a good agreement compared with the experimental results.
Retention of skills 2 years after completion of a postpartum hemorrhage simulation training program in rural Rwanda
Authors: Nathan Lisa M. , Patauli Desire , Nsabimana Damien , Bernstein Peter S. , Rulisa Stephen , Goffman Dena
Published: May 2016

Objective

To evaluate the long‐term retention of skills gained by rural physicians who completed a postpartum hemorrhage simulation‐training program.

Methods

A quasi‐experimental pre–post intervention study enrolled a convenience sample of generalist physicians in rural Rwanda. Participants underwent initial simulation training including pre‐ and post‐training testing in February 2012. Simulation drills to assess skill retention were conducted in March 2014. Participants were scored based on their communication, evaluation, and management skills. Median scores and inter‐quartile ranges were calculated and the Wilcoxon signed‐rank sum test was used to compare the pre‐training, post‐training, and retention scores. Physician confidence was assessed using a survey.

Results

In total, 11 physicians were enrolled; eight were available for the 2‐year skill‐retention evaluation. Significant improvements were observed when comparing participants’ pre‐training and post‐training communication (P = 0.03), evaluation (P = 0.05), and management (P = 0.02) scores, and there were no changes between participants’ post‐training and 2‐year communication (P > 0.99), evaluation (P = 0.16), and management (P = 0.46) scores. There were no differences in the self‐reported confidence measures across the duration of the study.

Conclusion

Simulation training is an effective method for teaching postpartum hemorrhage‐management skills to generalist physicians in rural areas and skills are retained for at least 2 years. Further studies could determine the optimal time intervals for refresher training.
OPTIMAL ASSET ALLOCATION IN LIFE INSURANCE: THE IMPACT OF REGULATION
Authors: Chen An , Hieber Peter
Published: May 2016

In a typical equity-linked life insurance contract, the insurance company is entitled to a share of return surpluses as compensation for the return guarantee granted to the policyholders. The set of possible contract terms might, however, be restricted by a regulatory default constraint — a fact that can force the two parties to initiate sub-optimal insurance contracts. We show that this effect can be mitigated if regulatory policy is more flexible. We suggest that the regulator implement a traffic light system where companies are forced to reduce the riskiness of their asset allocation in distress. In a utility-based framework, we show that the introduction of such a system can increase the benefits of the policyholder without deteriorating the benefits of the insurance company. At the same time, default probabilities (and thus solvency capital requirements) can be reduced.
CPR-associated right ventricular rupture in the setting of pulmonary embolism
Authors: Hickey Tyler B. M. , Gill Ginjeet Gina K. , Seidman Michael A. , Webber Douglas L.
Published: May 2016

Cardiopulmonary resuscitation (CPR) is an inherently traumatic procedure. Successful resuscitations are often complicated by iatrogenic injuries to structures of the neck, thorax, or abdomen. Rib and sternal fractures are the most frequently induced injuries. However, rare and life-threatening trauma to vital organs such as the heart may also occur during CPR. We describe a novel case of CPR-associated right ventricular rupture in a woman with acute-on-chronic pulmonary embolism and no known pre-existing cardiac disease. We propose that chest compressions in the setting of elevated right ventricular pressure resulted in cardiac rupture, in this case.
Direct numerical simulation of a turbulent hydraulic jump: turbulence statistics and air entrainment
Authors: Mortazavi Milad , Le Chenadec Vincent , Moin Parviz , Mani Ali
Published: May 2016

We present direct numerical simulation (DNS) of a stationary turbulent hydraulic jump with inflow Froude number of 2, Weber number of 1820 and density ratio of 831, consistent with ambient water–air systems, all based on the inlet height and inlet velocity. A non-dissipative geometric volume of fluid (VOF) method is used to track the detailed interactions between turbulent flow structures and the nonlinear interface dynamics. Level set equations are also solved concurrent with VOF in order to calculate the interface curvature and surface tension forces. The mesh resolution is set to resolve a wide range of interfacial scales including the Hinze scale. Calculations are compared against experimental data of void fraction and interfacial scales indicating, reasonable agreement despite a Reynolds number mismatch. Multiple calculations are performed confirming weak sensitivity of low-order statistics and void fraction on the Reynolds number. The presented results provide, for the first time, a comprehensive quantitative data for a wide range of phenomena in a turbulent breaking wave using DNS. These include mean velocity fields, Reynolds stresses, turbulence production and dissipation, velocity spectra and air entrainment data. In addition, we present the energy budget as a function of streamwise location by keeping track of various energy exchange processes in the wake of the jump. The kinetic energy is mostly transferred to pressure work, potential energy and dissipation while surface energy plays a less significant role. Our results indicate that the rate associated with various energy exchange processes peak at different streamwise locations, with exchange to pressure work flux peaking first, followed by potential energy flux and then dissipation. The energy exchange process spans a streamwise length of order ${\sim}10$ jump heights. Furthermore, we report statistics associated with bubble transport downstream of the jump. The bubble formation is found to have a periodic nature. Meaning that the bubbles are generated in patches with a specific frequency associated with the roll-up frequency of the roller at the toe of the jump, with its footprint apparent in the velocity energy spectrum. Our study also provides the ensemble-averaged statistics of the flow which we present in this paper. These results are useful for the development and validation of reduced-order models such as dissipation models in wave dynamics simulations, Reynolds-averaged Navier–Stokes models and air entrainment models.
Hydraulic model of cerebral arteriovenous malformations
Authors: Golovin S. V. , Khe A. K. , Gadylshina K. A.
Published: May 2016

The paper presents a model of a cerebral vascular system including two types of vessel networks (arterial and venous) joined by a porous medium as a substitute to a microcapillary system. The aim of the paper is to reproduce numerically experimental data on endovascular measurements of fluid velocity and pressure in the afferent artery and the efferent vein of the arteriovenous malformation (AVM). The suggested model qualitatively simulates all the main features of the experimental $vp$-diagrams: presence of the time shift between velocity and pressure waves, semicircular shape of the diagram, difference in the direction of circulation in the arterial and venous parts and upper-left drift of the diagram during the embolisation of the AVM. The velocity–pressure time shift is analysed on the modelling example of pulsation flow within a vessel in a cylindrical porous medium. The demonstrated adequacy of the model allows its further use for simulation of various strategies of AVM treatment, haemorrhage risk estimations, etc.
Recovery of the inherent dynamics of noise-driven amplifier flows
Authors: Iñigo Juan Guzmán , Sipp Denis , Schmid Peter J.
Published: May 2016

Unsteadiness in noise amplifier flows is driven and sustained by upstream environmental perturbations. A dynamic mode decomposition performed with snapshots taken in the statistically steady state extracts marginally stable dynamic modes, which mimic the sustained dynamics but miss the actual intrinsic stable behaviour of these flows. In this study, we present an alternative data-driven technique which attempts to identify and separate the intrinsic linear stable behaviour from the driving term. This technique uses a system-identification algorithm to extract a reduced state-space model of the flow from time-dependent input–output data. Such a model accurately predicts the values of the velocity field (output) from measurements of an upstream sensor that captures the effect of the incoming perturbations (input). The methodology is illustrated on a two-dimensional boundary layer subject to Tollmien–Schlichting instabilities, a canonical example of flow acting as a noise amplifier. The spectrum of the identified model compares well with the results reported in literature for the full-order system. Yet the comparison appears to be only qualitative, due to the poor robustness properties of eigenvalue spectra in noise-amplifier flows. We therefore advocate the use of the frequency response between the upstream sensor and the flow dynamics, which is revealed to be a robust quantity. The frequency response is validated against full-order computations and compares well with a local spatial stability analysis.