bluuebunny/crossref_metadata_2025 huggingface dataset:
Stress-related psychological symptoms contribute to axial pain persistence after motor vehicle collision: path analysis results from a prospective longitudinal study
Authors: Feinberg Rose K. , Hu JunMei , Weaver Mark A. , Fillingim Roger B. , Swor Robert A. , Peak David A. , Jones Jeffrey S. , Rathlev Niels K. , Lee David C. , Domeier Robert M. , Hendry Phyllis L. , Liberzon Israel , McLean Samuel A.
Published: January 2017

Posttraumatic stress disorder (PTSD) symptoms and pain after traumatic events such as motor vehicle collision (MVC) have been proposed to be mutually promoting. We performed a prospective multicenter study that enrolled 948 individuals who presented to the emergency department within 24 hours of MVC and were discharged home after evaluation. Follow-up evaluations were completed 6 weeks, 6 months, and 1 year after MVC. Path analysis results supported the hypothesis that axial pain after MVC consistently promotes the maintenance of hyperarousal and intrusive symptoms, from the early weeks after injury through 1 year. In addition, path analysis results supported the hypothesis that one or more PTSD symptom clusters had an influence on axial pain outcomes throughout the year after MVC, with hyperarousal symptoms most influencing axial pain persistence in the initial months after MVC. The influence of hyperarousal symptoms on pain persistence was only present among individuals with genetic vulnerability to stress-induced pain, suggesting specific mechanisms by which hyperarousal symptoms may lead to hyperalgesia and allodynia. Further studies are needed to better understand the specific mechanisms by which pain and PTSD symptoms enhance one another after trauma, and how such mechanisms vary among specific patient subgroups, to better inform the development of secondary preventive interventions.
Spinal intracellular metabotropic glutamate receptor 5 (mGluR5) contributes to pain and c-fos expression in a rat model of inflammatory pain
Authors: Vincent Kathleen , Wang Shu Fan , Laferrière André , Kumar Naresh , Coderre Terence J.
Published: January 2017

Metabotropic glutamate receptor 5 (mGluR5) is an excitatory G-protein-coupled receptor (GPCR) present in the spinal cord dorsal horn (SCDH) where it has a well-established role in pain. In addition to its traditional location on the cytoplasmic membrane, recent evidence shows that these receptors are present intracellularly on the nuclear membrane in the spinal cord dorsal horn and are implicated in neuropathic pain. Nuclear mGluR5 is a functional receptor that binds glutamate entering the cell through the neuronal glutamate transporter (GT) EAAT3 and activates transcription factor c-fos, whereas plasma membrane mGluR5 is responsible for c-junactivation. Here, we extend these findings to a model of inflammatory pain using complete Freund's adjuvant (CFA) and show that nuclear mGluR5 is also upregulated in the spinal cord dorsal horn following inflammation. We also show that pretreatment with an excitatory amino acid transporter (EAAT) inhibitor attenuates pain and decreases Fos, but not Jun, expression in complete Freund's adjuvant rats. In contrast, selective glial glutamate transporter inhibitors are pronociceptive and increase spinal glutamate concentrations. Additionally, we found that permeable mGluR5 antagonists are more effective at attenuating pain and Fos expression than nonpermeable group I mGluR antagonists. Taken together, these results suggest that under inflammatory conditions, intracellular mGluR5 is actively involved in the relay of nociceptive information in the spinal cord.
It is a painful somatic symptom, not the history of cancer/malignancy that is associated with depression: findings from multiple national surveys
Authors: Johnson Krystina , Politis Maria D. , Hansen Andrew R. , McKenzie Lindsey E. , Duncan Dustin T. , Zhang Jian
Published: January 2017

Medical case management has improved in the past few decades, changing the dynamic interaction between depression and prevalent medical diseases. It is relevant to describe the comorbidity between depression and medical diseases to further improve the effectiveness of case management. We analyzed the data of adults aged 20 years and older, who completed depression screening as a part of the National Health and Nutrition Examination Survey, 2005 to 2012. Depression was ascertained using the Patient Health Questionnaire, a 9-item screening instrument asking about the frequency of depression symptoms over the past 2 weeks. Comorbid diseases were assessed in a self-reported personal interview on doctor-diagnosed health conditions. The associations between depression and medical diseases were limited to the diseases with painful somatic symptoms. Reported from 19.78% of men and 27.84% of women, arthritis was the most prevalent chronic disease, and was the only one consistently associated with depression. The odds ratio of moderate to severe depression was 1.65 (95% confidence interval = 1.12-2.44) for men and 2.11 (1.63-2.99) for women with arthritis compared with their counterparts free of arthritis. Moderate/severe depression was associated with a history of heart disease among men (2.45 [1.19-5.06]) and angina/angina pectoris among women (2.13 [1.07-4.26]). No associations were found between depression and cancer/malignancy, either among men or women. The potential impact of pain management on depression prevention among general population is substantial; more efforts are needed to assess chronic pain to facilitate timely prevention and treatment of depression and comorbid medical conditions.
Chronic stress exacerbates neuropathic pain via the integration of stress-affect–related information with nociceptive information in the central nucleus of the amygdala
Authors: Li Ming-Jia , Liu Ling-Yu , Chen Lin , Cai Jie , Wan You , Xing Guo-Gang
Published: January 2017

Exacerbation of pain by chronic stress and comorbidity of pain with stress-related psychiatric disorders, including anxiety and depression, represent significant clinical challenges. However, the underlying mechanisms still remain unclear. Here, we investigated whether chronic forced swim stress (CFSS)–induced exacerbation of neuropathic pain is mediated by the integration of stress-affect–related information with nociceptive information in the central nucleus of the amygdala (CeA). We first demonstrated that CFSS indeed produces both depressive-like behaviors and exacerbation of spared nerve injury (SNI)-induced mechanical allodynia in rats. Moreover, we revealed that CFSS induces both sensitization of basolateral amygdala (BLA) neurons and augmentation of long-term potentiation (LTP) at the BLA-CeA synapse and meanwhile, exaggerates both SNI-induced sensitization of CeA neurons and LTP at the parabrachial (PB)-CeA synapse. In addition, we discovered that CFSS elevates SNI-induced functional up-regulation of GluN2B-containing NMDA (GluN2B-NMDA) receptors in the CeA, which is proved to be necessary for CFSS-induced augmentation of LTP at the PB-CeA synapse and exacerbation of pain hypersensitivity in SNI rats. Suppression of CFSS-elicited depressive-like behaviors by antidepressants imipramine or ifenprodil inhibits the CFSS-induced exacerbation of neuropathic pain. Collectively, our findings suggest that CFSS potentiates synaptic efficiency of the BLA-CeA pathway, leading to the activation of GluN2B-NMDA receptors and sensitization of CeA neurons, which subsequently facilitate pain-related synaptic plasticity of the PB-CeA pathway, thereby exacerbating SNI-induced neuropathic pain. We conclude that chronic stress exacerbates neuropathic pain via the integration of stress-affect–related information with nociceptive information in the CeA.
Divergent functions of the left and right central amygdala in visceral nociception
Authors: Sadler Katelyn E. , McQuaid Neal A. , Cox Abigail C. , Behun Marissa N. , Trouten Allison M. , Kolber Benedict J.
Published: January 2017

The left and right central amygdalae (CeA) are limbic regions involved in somatic and visceral pain processing. These 2 nuclei are asymmetrically involved in somatic pain modulation; pain-like responses on both sides of the body are preferentially driven by the right CeA, and in a reciprocal fashion, nociceptive somatic stimuli on both sides of the body predominantly alter molecular and physiological activities in the right CeA. Unknown, however, is whether this lateralization also exists in visceral pain processing and furthermore what function the left CeA has in modulating nociceptive information. Using urinary bladder distension (UBD) and excitatory optogenetics, a pronociceptive function of the right CeA was demonstrated in mice. Channelrhodopsin-2–mediated activation of the right CeA increased visceromotor responses (VMRs), while activation of the left CeA had no effect. Similarly, UBD-evoked VMRs increased after unilateral infusion of pituitary adenylate cyclase–activating polypeptide in the right CeA. To determine intrinsic left CeA involvement in bladder pain modulation, this region was optogenetically silenced during noxious UBD. Halorhodopsin (NpHR)-mediated inhibition of the left CeA increased VMRs, suggesting an ongoing antinociceptive function for this region. Finally, divergent left and right CeA functions were evaluated during abdominal mechanosensory testing. In naive animals, channelrhodopsin-2–mediated activation of the right CeA induced mechanical allodynia, and after cyclophosphamide-induced bladder sensitization, activation of the left CeA reversed referred bladder pain–like behaviors. Overall, these data provide evidence for functional brain lateralization in the absence of peripheral anatomical asymmetries.
Predictive Factors That May Contribute to Secondary Insults With Nursing Interventions in Adults With Traumatic Brain Injury
Authors: Nyholm Lena , Howells Tim , Enblad Per
Published: January 2017

Background: Nursing interventions pose risks and benefits to patients with traumatic brain injury at a neurointensive care unit. Objectives: The aim of this study was to investigate the risk of inducing high intracranial pressure (ICP) related to interventions and whether intracranial compliance, baseline ICP, or autoregulation could be used as predictors. Methods: The study had a quantitative, prospective, observational design. Twenty-eight patients with TBI were included, and 67 interventions were observed. The definition of a secondary ICP insult was ICP of 20 mm Hg or greater for 5 minutes or more within a continuous 10-minute period. Results: Secondary ICP insults related to nursing interventions occurred in 6 patients (21%) and 8 occasions (12%). Patients with baseline ICP of 15 mm Hg or greater had 4.7 times higher risk of developing an insult. The predictor with the best combination of sensitivity and specificity was baseline ICP. Conclusions: Baseline ICP of 15 mm Hg or greater was the most important factor to determine the risk of secondary ICP insult related to nursing intervention.
Socioeconomic Disparities in Mortality Among Women With Incident Breast Cancer Before and After Implementation of Medicare Part D
Authors: Nattinger Ann B. , Wozniak Erica M. , McGinley Emily L. , Li Jianing , Laud Purushottam , Pezzin Liliana E.
Published: January 2017

Background:

Breast cancer patients exhibit survival disparities based on socioeconomic status (SES). Disparities may be attributable to access to expensive oral endocrine agents.

Objectives:

Define recent socioeconomic disparities in breast cancer survival and determine whether these improved after implementation of the Medicare Part D program.

Design:

Difference-in-difference natural experiment of women diagnosed and treated before or after implementation of Medicare Part D.

Subjects:

Female Medicare beneficiaries with early-stage breast cancer: 54,772 diagnosed in 2001 and 46,371 in 2007.

Measures:

SES was based on Medicaid enrollment and zip code per capita income, all-cause mortality from Medicare, and cause of death from National Death Index.

Results:

Among women diagnosed pre-Part D, 40.5% of poor beneficiaries had died within 5 years compared with 20.3% of high-income women (P<0.0001). Post-Part D, 33.6% of poor women and 18.4% of high-income women died by 5 years. After adjustment for potential confounders, improvement in all-cause mortality post-Part D was greater for poorer women compared with more affluent women (P=0.002). However, absolute improvement in breast cancer-specific mortality was 1.8%, 1.2%, and 0.8% (P=0.88 for difference in improvement by SES), respectively for poor, near-poor, and high-income women, whereas analogous improvement in mortality from other causes was 5.1%, 3.8%, and 0.9% (P=0.067 for difference in improvement by SES).

Conclusions:

Large survival disparities by SES exist among breast cancer patients. The Part D program successfully ameliorated SES disparities in all-cause mortality. However, improvement was concentrated in causes of death other than breast cancer, suggesting remaining gaps in care.
A Comparison of Lecture Versus Lecture Plus Simulation
Authors: Bodine Jennifer L. , Miller Sylvia
Published: January 2017

Terminally ill patients frequently visit emergency departments for palliative care. However, studies have documented that staff do not have the knowledge base necessary to provide quality end-of-life care. This lack of educational preparedness led to a pilot study that compared 2 educational approaches to teaching emergency nurses the End-of-Life Nursing Education Consortium Curriculum. Three 8-hour lectures and three 8-hour lectures plus simulation classes were presented to nurses who volunteered from the emergency department of a level I trauma center. This study showed no statistical significance in knowledge base between the 2 educational approaches. However, the ELNEC curriculum increased the knowledge base of both groups. As a result of the course, the palliative care team has seen a significant increase in palliative care consults from the emergency department.
Palliative Care in the Management of Pain, Odor, and Exudate in Chronic Wounds at the End of Life
Authors: Kelechi Teresa J. , Prentice Margie , Madisetti Mohan , Brunette Glenda , Mueller Martina
Published: January 2017

Palliative care approaches that effectively manage distressful symptoms associated with wounds at the end of life remain elusive. This 4-week study examined a topical wound powder RGN107 for reducing pain, odor, and exudate in 50 patients with pressure ulcers, skin tears, and malignant/fungating and vascular wounds receiving hospice or palliative care and explored quality of life for the caregiver. Through an observational design, the outcomes were measured with visual analog scales, 2 pain questionnaires, and a caregiver quality-of-life instrument. Intent-to-treat analyses were used. Statistically significant reductions in pain (P = .001), odor (P = .04), and exudate (P = .00003) were observed. Caregiver quality of life remained unchanged (P = .28); however, improvements were noted in 3 subscales. Findings suggest topical RGN107 reduced pain, odor, and exudate in a highly challenged population with wounds at the end of life. A larger comparative effectiveness trial should be conducted with other wound powder comparators and usual care approaches and should include cost benefits.
Increased nitrogen input enhances
Kandelia obovata
seedling growth in the presence of invasive
Spartina alterniflora
in subtropical regions of China
Authors: Cui Xiaowei , Song Weimin , Feng Jianxiang , Jia Dai , Guo Jiemin , Wang Zhonglei , Wu Hao , Qi Fei , Liang Jie , Lin Guanghui
Published: January 2017

Mangroves in China are severely affected by the rapid invasion of the non-native species
Spartina alterniflora
. Although many studies have addressed the possible impacts of
S. alterniflora
on the performance of mangrove seedlings, how excessive nitrogen (N) input due to eutrophication affects the interactions between mangrove species and
S. alterniflora
remains unknown. Here, we report the results from a mesocosm experiment using seedlings of the native mangrove species
Kandelia obovata
and the exotic
S. alterniflora
grown in monoculture and mixed culture under no nitrogen addition and nitrogen (N) addition treatments for 18 months. Without N addition, the presence of
S. alterniflora
inhibited the growth of
K. obovata
seedlings. Excessive N addition significantly increased the growth rate of
K. obovata
in both cultures. However, the positive and significantly increasing relative interaction intensity index under excessive N input suggested that the invasion of
S. alterniflora
could favour the growth of
K. obovata
under eutrophication conditions. Our results imply that excessive N input in southeastern China can increase the competitive ability of mangrove seedlings against invasive
S. alterniflora
.
Evolutionary interplay between structure, energy and epistasis in the coat protein of the
ϕX
174 phage family
Authors: Redondo Rodrigo A. F. , de Vladar Harold P. , Włodarski Tomasz , Bollback Jonathan P.
Published: January 2017

Viral capsids are structurally constrained by interactions among the amino acids (AAs) of their constituent proteins. Therefore, epistasis is expected to evolve among physically interacting sites and to influence the rates of substitution. To study the evolution of epistasis, we focused on the major structural protein of the
ϕ
X174 phage family by first reconstructing the ancestral protein sequences of 18 species using a Bayesian statistical framework. The inferred ancestral reconstruction differed at eight AAs, for a total of 256 possible ancestral haplotypes. For each ancestral haplotype and the extant species, we estimated,
in silico
, the distribution of free energies and epistasis of the capsid structure. We found that free energy has not significantly increased but epistasis has. We decomposed epistasis up to fifth order and found that higher-order epistasis sometimes compensates pairwise interactions making the free energy seem additive. The d
N
/d
S
ratio is low, suggesting strong purifying selection, and that structure is under stabilizing selection. We synthesized phages carrying ancestral haplotypes of the coat protein gene and measured their fitness experimentally. Our findings indicate that stabilizing mutations can have higher fitness, and that fitness optima do not necessarily coincide with energy minima.
Experimental measurements of water molecule binding energies for the second and third solvation shells of [Ca(H
2
O)

n

]
2+
complexes
Authors: Bruzzi E. , Stace A. J.
Published: January 2017

Further understanding of the biological role of the Ca
2+
ion in an aqueous environment requires quantitative measurements of both the short- and long-range interactions experienced by the ion in an aqueous medium. Here, we present experimental measurements of binding energies for water molecules occupying the second and, quite possibly, the third solvation shell surrounding a central Ca
2+
ion in [Ca(H
2
O)

n

]
2+
complexes. Results for these large, previously inaccessible, complexes have come from the application of finite heat bath theory to kinetic energy measurements following unimolecular decay. Even at
n
 = 20, the results show water molecules to be more strongly bound to Ca
2+
than would be expected just from the presence of an extended network of hydrogen bonds. For
n
 > 10, there is very good agreement between the experimental binding energies and recently published density functional theory calculations. Comparisons are made with similar data recorded for [Ca(NH
3
)

n

]
2+
and [Ca(CH
3
OH)

n

]
2+
complexes.
Individual differences in visual motion perception and neurotransmitter concentrations in the human brain
Authors: Takeuchi Tatsuto , Yoshimoto Sanae , Shimada Yasuhiro , Kochiyama Takanori , Kondo Hirohito M.
Published: January 2017

Recent studies have shown that interindividual variability can be a rich source of information regarding the mechanism of human visual perception. In this study, we examined the mechanisms underlying interindividual variability in the perception of visual motion, one of the fundamental components of visual scene analysis, by measuring neurotransmitter concentrations using magnetic resonance spectroscopy. First, by psychophysically examining two types of motion phenomena—motion assimilation and contrast—we found that, following the presentation of the same stimulus, some participants perceived motion assimilation, while others perceived motion contrast. Furthermore, we found that the concentration of the excitatory neurotransmitter glutamate–glutamine (Glx) in the dorsolateral prefrontal cortex (Brodmann area 46) was positively correlated with the participant's tendency to motion assimilation over motion contrast; however, this effect was not observed in the visual areas. The concentration of the inhibitory neurotransmitter γ-aminobutyric acid had only a weak effect compared with that of Glx. We conclude that excitatory process in the suprasensory area is important for an individual's tendency to determine antagonistically perceived visual motion phenomena.

This article is part of the themed issue ‘Auditory and visual scene analysis'.
Mono-Association withLactobacillus plantarumDisrupts Intestinal Homeostasis in adultDrosophila
Authors: Fast David , Duggal Aashna , Foley Edan
Published: January 2017

The microbiome ofDrosophilapromotes intestinal stem cell division through evolutionarily conserved biochemical pathways. As such, axenic flies have lower rates of gut stem cell division than age-matched wild type counterparts. Additionally, flies with a full consortium of symbiotic bacteria are shorter lived than those maintained in the absence of a microbiome. However, we do not know if stem cell division is essential for symbiont-dependent regulation of adult fly lifespan. To determine if individual symbionts cause aging-dependent death inDrosophila, we examined the impacts of common symbionts on host longevity. In this study, we found that mono-association of adultDrosophilawithLactobacillus plantarum, a widely reported fly symbiont, and member of the probioticLactobacillusgenus, curtails adult longevity relative to germ-free counterparts. However, the effects ofplantarumon lifespan were independent of intestinal aging. Instead, we found that association withplantarumcauses an extensive intestinal pathology within the host, characterized by loss of intestinal stem cells, impaired epithelial renewal, and a gradual erosion of epithelial integrity. Our study uncovers an unknown aspect ofLactobacillus plantarum-Drosophilainteractions, and establishes a simple model to characterize symbiont-dependent disruption of intestinal homeostasis.
Red Bull Gives You Incentive Motivation: Understanding Placebo Effects of Energy Drinks on Human Cognitive Performance
Authors: Schmidt Liane , Chandon Pierre , Pessiglione Mathias , Plassmann Hilke
Published: January 2017

The consumption of cognitive enhancers like energy drinks (EnD) is on the rise, but do they really improve cognitive performance, and, if yes, why? We examined two novel psychological mechanisms. First, we dissociated the role of expectations and actual consumption by crossing what people consumed—Red Bull Silver Edition or a similar-tasting Sprite soda—and what they thought they consumed. We found that participants performed better in a numerical Stroop task when they believed that they had consumed an EnD, irrespective of what they had actually consume, Second, we investigated the role of motivation for such a placebo effect of EnD. We found that expected, but not actual, consumption of EnD increased the effects of incentives on cognitive performance. Our results suggest that believing that one consumes an EnD increased participants’ motivation to perform and thus enhanced their performance.

Significance statement

Academic doping has become increasingly popular on campuses around the globe over the last years. However, it remains unknown if and how commercially available cognitive enhancers such as energy drinks (EnD) impact cognitive performance. We varied actual and believed consumption of an EnD and measured cognitive performance and its allocation according to the magnitude of points to earn. We found that the belief that one has consumed an EnD but not its actual consumption, increased cognitive performance specifically in high point trials compared to low point trials. These findings provide novel insights into motivational processes underpinning marketing-led expectancy effects, and contribute to the current public policy debate on the use and abuse of increased alertness and concentration claims for EnD.
Mapping Billions of Short Reads to a Reference Genome
Authors: Hung Jui-Hung , Weng Zhiping
Published: January 2017

Rapid development and commercialization of instruments that can accurately, rapidly, and cheaply sequence billions of DNA bases is revolutionizing molecular biology and medicine. Because a reference genome is usually available, the first bioinformatics challenge presented by the new generation of high-throughput sequencers is the genome mapping problem, where each read is mapped to a reference genome to reveal its location(s). An introduction to mapping algorithms, as well as factors that influence their results, is provided here.
Twin-rotor hover performance examination using overlap tests
Authors: Shahmiri Farid
Published: January 2017

Purpose

The aim of this paper was to experimentally examine twin-rotor hover performance for different rotor overlap ratios at practical rotor loading.

Design/methodology/approach

The methodology was formed based on data measurements for a designed twin-rotor test model and development of hover performance mathematical models. Thus, measurements were made using a central composite test plan, and then mathematical models for thrust power required power loading (PL) and figure of merit (FM) as functions of collective pitch tip speed; rotor overlap ratio was obtained. In the present paper, the test model consisted of two three-bladed rotors with a diameter of 220 mm and a blade aspect ratio of 16.05. The blades were of a rectangular planform with NACA 0012 cross sections and had no twist or taper. The model was built such that the rear rotor was fixed on the fuselage, and the front rotor could move longitudinally for tests up to about 40 per cent overlap ratio in hover.

Findings

The best hover aerodynamic efficiency (maximum PL of 14.6 kg/kW) was achieved for non-overlapped rotors at a low value of disc loading (DL) and also at FM of 0.6 at that DL. This result was in agreement with blade element momentum theory predictions.

Practical implications

Results for the twin-rotor test model can be generalized for actual tandem helicopters through the Reynolds number transformation technique and also some modifications.

Originality/value

Design and construction of the twin-rotor test model and experimental measurements of hover performance based on an optimal test plan were performed for the first time.
Cooperative target localization using multiple UAVs with out-of-sequence measurements
Authors: Wang Xiaogang , Qin Wutao , Bai Yuliang , Cui Naigang
Published: January 2017

Purpose

The time delay would occurs when the measurements of multiple unmanned aerial vehicles (UAVs) are transmitted to the date processing center during cooperative target localization. This problem is often named as the out-of-sequence measurement (OOSM) problem. This paper aims to present a nonlinear filtering based on solving the Fokker–Planck equation to address the issue of OOSM.

Design/methodology/approach

According to the arrival time of measurement, the proposed nonlinear filtering can be divided into two parts. The non-delay measurement would be fused in the first part, in which the Fokker–Planck equation is utilized to propagate the conditional probability density function in the forward form. The time delay measurement is fused in the second part, in which the Fokker–Planck is used in the backward form approximately. The Bayes formula is applied in both parts during the measurement update.

Findings

Under the Bayesian filtering framework, this nonlinear filtering is not only suitable for the Gaussian noise assumption but also for the non-Gaussian noise assumption. The nonlinear filtering is applied to the cooperative target localization problem. Simulation results show that the proposed filtering algorithm is superior to the previous Y algorithm.

Practical implications

In this paper, the research shows that a better performance can be obtained by fusing multiple UAV measurements and treating time delay in measurement with the proposed algorithm.

Originality/value

In this paper, the OOSM problem is settled based on solving the Fokker–Planck equation. Generally, the Fokker–Planck equation can be used to predict the probability density forward in time. However, to associate the current state with the state related to OOSM, it would be used to propagate the probability density backward either.
Experimental experience of cold starting a spark ignition UAV engine using low volatility fuel
Authors: Hooper Peter
Published: January 2017

Purpose

The purpose of this paper is to present results of practical experience of cold starting a gasoline engine on low volatility fuel suitable for unmanned aerial vehicle (UAV) deployment.

Design/methodology/approach

Experimental research and development is carried out via dynamometer testing of systems capable of achieving cold start of a spark ignition UAV engine on kerosene JET A-1 fuel.

Findings

Repeatable cold starts have been satisfactorily achieved at ambient temperatures of 5°C. The approximate threshold for warm engine restart has also been established.

Practical implications

For safety and supply logistical reasons, the elimination of the use of gasoline fuel offers major advantages not only for UAVs but also for other internal combustion engine-powered equipment to be operated in military theatres of operation. For gasoline crankcase-scavenged two-stroke cycle engines, this presents development challenges in terms of modification of the lubrication strategy, achieving acceptable performance characteristics and the ability to successfully secure repeatable engine cold start.

Originality/value

The majority of UAVs still operate on gasoline-based fuels. Successful modification to allow low volatility fuel operation would address single fuel policy objectives.
Improved efficiency of an unmanned air vehicle IC engine using computational modelling and experimental verification
Authors: Hooper Peter , Al-Shemmeri Tarik
Published: January 2017

Purpose

This paper aims to present experimental results of gasoline-fuelled engine operation of a crankcase-scavenged two-stroke cycle engine used for unmanned air vehicle (UAV)/unmanned air system application and to cross correlate with computational fluid dynamic modelling results.

Design/methodology/approach

Computational modelling of the engine system was conducted using the WAVE software supported by the experimental research and development via dynamometer testing of a spark ignition UAV engine to construct a validated computational model exploring a range of fuel delivery options.

Findings

Experimental test data and computational simulation have allowed an assessment of the potential advantages of applying direct in-cylinder fuel injection.

Practical implications

The ability to increase system efficiency offers significant advantages in terms of maximising limited resources and extending mission duration capabilities. The computational simulation and validation via experimental test experience provides a means of assessment of possibilities that are costly to explore experimentally and offers added confidence to be able to investigate possibilities for the development of similar future engine designs.

Originality/value

The software code used has not been applied to such crankcase-scavenged two-stroke cycle engines and provides a valuable facility for further simulation of the twin cylinder horizontally opposed design to offer further system optimisation and exploration of future possibilities.
Satellite optical misalignment test procedure subject to theodolites
Authors: Mortazavi Seyed Hossein
Published: January 2017

Purpose

The purpose of this study is to address the concept and the step-by-step procedure of a high-precision optical alignment test for spacecrafts using digital theodolites. The proposed scheme focuses on the non-contact alignment qualification of spacecraft components during the integration and test phases until the launch event.

Design/methodology/approach

The proposed approach is based on the exploitation of the auto-collimation feature of theodolites and several prisms attached to the requested component and satellite configuration. As soon as the misalignment measurement including the difference between the real and desired attitude or position aberration of an instrument is made, the results must be transformed from the component level to the system level for misalignment error identification in the spacecraft dynamic model.

Findings

The paper introduces the main instruments, the defined coordinate systems and the architecture of the optical spacecraft misalignment test. Moreover, the guideline of the test implementation and the resulting data process have been presented carefully.

Research limitations/implications

There is no limitation associated with this method because the procedure is applicable for high-precision typical missions.

Practical implications

This paper describes a fully implementable scheme to examine any possible inaccuracy in mounting of the spacecraft components both in position and orientation. The test can be performed without the need for a huge budget or complicated hardwares.

Originality/value

The contribution of this work revolves around illustrating the context and procedure of the spacecraft misalignment test which has remained unknown in literature despite the frequent implementation in the different satellite projects.
Nonlinear aerodynamics of an unmanned aircraft in wind shear
Authors: Keshmiri Shawn S. , Lan Edward , Hale Richard
Published: January 2017

Purpose

The purpose of this paper is to evaluate the accuracy of linear and quasi-steady aerodynamic models of aircraft aerodynamic models when a small unmanned aerial system flies in the presence of strong wind and gust at a high angle of attack and a high sideslip angle.

Design/methodology/approach

Compatibility analysis were done to improve the quality of recorded flight test data. A robust method called fuzzy logic modeling is used to set up the aerodynamic models. The reduced frequency is used to represent the unsteadiness of the flow field according to Theodorsen’s theory. The work done by the aerodynamic moments on the motions is used as the criteria of stability.

Findings

In portions of flight, aircraft’s stability and control derivatives were unstable and nonlinear functions of airflow angles and angular rates. The roll angle had an important effect on unsteadiness of directional oscillatory damping derivatives. The pilot-induced oscillation and wing rock possibilities were investigated and dismissed so that the lateral directional oscillatory motion was classified as a nonlinear Dutch roll oscillation. Major modeling enhancements or real-time parameter identification are required for the control of a small unmanned aerial system in off-nominal conditions. The robustness tests of all-weather autopilot systems must be done with consideration of sign change.

Originality/value

Oscillatory damping derivatives were reconstructed using flight test data and the inadequacy of engineering level software in predicting this type of instability observed and demonstrated for a flight in the presence of wind shear and external disturbances.
Design of conventional and neural network based controllers for a single-shaft gas turbine
Authors: Asgari Hamid , Fathi Jegarkandi Mohsen , Chen XiaoQi , Sainudiin Raazesh
Published: January 2017

Purpose

The purpose of this paper is to develop and compare conventional and neural network-based controllers for gas turbines.

Design/methodology/approach

Design of two different controllers is considered. These controllers consist of a NARMA-L2 which is an artificial neural network-based nonlinear autoregressive moving average (NARMA) controller with feedback linearization, and a conventional proportional-integrator-derivative (PID) controller for a low-power aero gas turbine. They are briefly described and their parameters are adjusted and tuned in Simulink-MATLAB environment according to the requirement of the gas turbine system and the control objectives. For this purpose, Simulink and neural network-based modelling is used. Performances of the controllers are explored and compared on the base of design criteria and performance indices.

Findings

It is shown that NARMA-L2, as a neural network-based controller, has a superior performance to PID controller.

Practical implications

This study aims at using artificial intelligence in gas turbine control systems.

Originality/value

This paper provides a novel methodology for control of gas turbines.
Modelling and robust attitude trajectory tracking control of 3-DOF four rotor hover vehicle
Authors: Amin Rooh ul , Li Aijun
Published: January 2017

Purpose

The purpose of this paper is to present μ-synthesis-based robust attitude trajectory tracking control of three degree-of-freedom four rotor hover vehicle.

Design/methodology/approach

Comprehensive modelling of hover vehicle is presented, followed by development of uncertainty model. A μ-synthesis-based controller is designed using the DK iteration method that not only handles structured and unstructured uncertainties effectively but also guarantees robust performance. The performance of the proposed controller is evaluated through simulations, and the controller is also implemented on experimental platform. Simulation and experimental results validate that μ-synthesis-based robust controller is found effective in: solving robust attitude trajectory tracking problem of multirotor vehicle systems, handling parameter variations and dealing with external disturbances.

Findings

Performance analysis of the proposed controller guarantees robust stability and also ensures robust trajectory tracking performance for nominal system and for 15-20 per cent variations in the system parameters. In addition, the results also ensure robust handling of wind gusts disturbances.

Originality/value

This research addresses the robust performance of hover vehicle’s attitude control subjected to uncertainties and external disturbances using μ-synthesis-based controller. This is the only method so far that guarantees robust stability and performance simultaneously.
Aeroelastic behaviour of UAV wings due to morphing
Authors: Ünlüsoy Levent , Yaman Yavuz
Published: January 2017

Purpose

The purpose of this paper is to analyse the effects of morphing on the aeroelastic behaviour of unmanned aerial vehicle (UAV) wings to make an emphasis on the required aeroelastic tailoring starting from the conceptual design of the morphing mechanisms.

Design/methodology/approach

In this study, flutter and divergence characteristics of a fully morphing wing design were discussed to show the dilapidating effect of morphing on the related parameters. The morphing wings were intended to achieve a high efficiency at different flight phases; thus, various morphing concepts were integrated into a UAV wing structure. Although it is considered beneficial to have the morphing capabilities to avoid the failure due to a possible wear out in flutter and divergence parameters; it is necessary to include the aeroelastic analyses at the early design phases. This study utilizes a combination of a reduced order structural model and Theodorsen unsteady aerodynamic model as primary analyses tools for flutter and divergence. The analyses were conducted by using an in-house developed pk-algorithm coupled with a commercial finite element analysis (FEA) tool. This approach yielded a fast solution capacity because of the state-space form used.

Findings

Analyses conducted showed that transition between take-off, climb, cruise and loiter phases yield a change in the flutter and divergence speeds as high as 138 and 305 per cent, respectively.

Practical implications

The research showed that an extensive aeroelastic investigation was required for morphing wing designs to achieve a failure safe design.

Originality/value

The research intends to highlight the possible deteriorating effects on structural design of morphing UAV wings by focusing on the aeroelastic characteristics. In addition to that, fundamental morphing concepts are compared in terms of the order of magnitude of their deteriorating effects.
Building information modelling, integrated project delivery and all that
Authors: Rowlinson Steve
Published: January 2017

Purpose

This paper aims to review the development of building information modelling (BIM) and integrated project delivery (IPD) in recent years and the process changes that BIM and IPD require.

Design/methodology/approach

A qualitative research methodology was applied which involved a comprehensive review of relevant literature leading to a better understanding of the history and development of BIM and IPD. A way forward is suggested for the future development of BIM and IPD.

Findings

The research revealed that the IPD approach is already ingrained within certain organisations and their supply chains. The issues of political will and business desire to change the existing procurement systems are examined. The need for fit with regional and national economic and cultural characteristics is a pre-requisite for successful change. Collaborative working, information exchange and trust only exist within the context of a trusted and reliable building information model that all can access, understand and manage.

Originality/value

This research pointed out that there is a need to overcome the institutional inertia that besets governments and their agencies and suggested that exemplar institutions and their projects are needed to lead the industry by integrating BIM into IPD through process change.
Categorising on-site problems
Authors: Thunberg Micael , Rudberg Martin , Karrbom Gustavsson Tina
Published: January 2017

Purpose

This study aims to identify and categorise common on-site problems from a supply chain management (SCM) perspective and to trace the origin of these problems in the construction project process, the supply chain or in the intersection between these processes. This allows for identification of how on-site problems affect SCM in construction projects and how they can be mitigated.

Design/methodology/approach

A literature review in combination with semi-structured interviews was used to identify on-site problems. This enabled triangulation and strengthened both construct validity and internal validity.

Findings

On-site problems can be categorised in one of the four following categories: material flows, internal communication, external communication or complexity. The first category has its origin in the supply chain, the second in the construction project process, the third in the supply chain-construction process intersection on site and the fourth in the construction project as a whole. The findings conclude that on-site problems often originate from construction companies’ lack of supply chain orientation.

Research limitations/implications

It is suggested that supply chain planning (SCP) can facilitate on-site problem mitigation in construction project management. This extends the body of knowledge of SCP in construction project management and supports the development of effective on-site construction project management.

Practical implications

The results show that SCP can aid construction project management in handling on-site problems earlier in the project process.

Originality/value

The main value lies in extending the body of knowledge in construction project management research by applying an SCM perspective and by introducing SCP to support more effective construction project management.
Socialisation in architectural education: a view from East Africa
Authors: Olweny Mark
Published: January 2017

Purpose

Concern for the state of architectural education in East Africa was a catalyst for this exploration of socialisation, which sought to understand socialisation and its influence on educational outcomes in the region. Socialisation within architectural education has long been known to influence how students acquire important aspects of the profession, building both values and a cultural ethos in the process. An appreciation of these processes in the context of East Africa adds to the wider understanding of the implicit curriculum in architectural education. The paper aims to discuss these issues.

Design/methodology/approach

An ethnographic study was undertaken in five architecture schools across Kenya, Tanzania and Uganda, making use of a mixed method approach incorporating document analysis, a questionnaire study, participant observations and focus group discussions as the data gathering instruments. Focus group discussions, as the primary data gathering method, acknowledged the social context of the study, with data gathered from multiple sites across the region.

Findings

As an integral component of architectural education, socialisation was evident at all stages of the educational process. Within the educational realm, contrasting expectations of students and instructors were evident, leading to conflicts that influenced the values acquired by students. This was seen in attitudes towards contemporary architectural issues within architectural education, and suggests that socialisation can at times have pronounced negative consequences.

Originality/value

The wider study represents the first comprehensive review of architectural education in the context of East Africa, and contributes to the global appreciation of the influence of socialisation on educational outcomes.
Am I a student and/or entrepreneur? Multiple identities in student entrepreneurship
Authors: Nielsen Suna Løwe , Gartner William B.
Published: January 2017

Purpose

The purpose of this paper is to study different aspects and tensional forces that play a role in the internal and contextual negotiation that takes place within students in the exploration of the possible identity of entrepreneur. It expands the knowledge of how the university context influences student entrepreneurial processes from a multiple identity perspective. The findings are related to discussions of entrepreneurship education.

Design/methodology/approach

A conceptual paper that presents a framework on student entrepreneurial identity sense making that is grounded in a multiple identity perspective. The framework is illustrated by ten narrative cases on student entrepreneurship.

Findings

The framework suggests four different ways students make sense of identity in the process of exploring the entrepreneurial identity along with their university studies. In this process students negotiate between the two identities of “student” and “entrepreneur”, both demanding in time, effort and commitment, and they in different manners struggle with balancing university belonging and entrepreneurial distinctiveness.

Originality/value

The framework serves as a point of departure for discussing the psychological processes and tensions associated with students’ entrepreneurial identity construction, and what it means to entrepreneurship education. It is suggested that universities to a higher degree have to view themselves as psychological institutional moratoriums and thus as platforms of identity explorations rather than deterministic systems preparing students for certain careers to support students in becoming entrepreneurs.