bluuebunny/crossref_metadata_2025 huggingface dataset:
The preferences of young adults with Type 1 diabetes at clinics using a discrete choice experiment approach: the D1 Now Study
Authors: Mc Morrow L. , O’ Hara M. C. , Hynes L. , Cunningham Á. , Caulfield A. , Duffy C. , Keighron C. , Mullins M. , Long M. , Walsh D. , Byrne M. , Kennelly B. , Gillespie P. , Dinneen S. F. , Doherty E. ,   with the D1 Now Study Group
Published: September 2018

Aim

Attending routine outpatient clinic appointments is a central self‐management behaviour of individuals living with Type 1 diabetes. A large number of young adults with Type 1 diabetes disengage from diabetes services, which may contribute to poor psychosocial and diabetes outcomes. The aim of this study is to elicit preferences from young adults with Type 1 diabetes regarding clinic‐related services to inform service delivery.

Methods

A discrete choice experiment was developed to understand the preferences of young adults with Type 1 diabetes for clinic‐related services.

Results

Young adults recruited from young adult Type 1 diabetes clinics in 2016 completed the experiment (n = 105). Young adults with Type 1 diabetes showed a preference for shorter waiting times, seeing a nurse and a consultant, relative to a nurse alone, and a flexible booking system compared with fixed appointment times. Results suggest no preference for a nurse and a doctor, relative to a nurse alone, or other optional services (e.g. seeing dietitians or psychologists), type of HbA1c test and digital blood glucose diaries over paper‐based diaries.

Conclusion

This study highlights aspects of routine clinic appointments that are valued by young adults living with Type 1 diabetes, namely shorter waiting times at clinic, the option to see both a nurse and consultant at each visit and a flexible clinic appointment booking system. These findings suggest young adults with Type 1 diabetes value convenience and should help services to restructure their clinics to be more responsive to the needs of young adults.
Discovering the associations between test items in an examination
Authors: Dong Ligang , Tang Liujun , Liu Shihuan , Jiang Xian
Published: September 2018

An examination is .an important approach to comprehensively evaluate students' abilities. An examination paper is composed of test items. Most studies assume that test items are independent, but there may, in fact, be associations among test items. How to select test items with low correlations into a test paper is our concern. Meanwhile, for
diagnostic learning, students must perform highly relevant exercises to help them efficiently understand the concepts included in the test items. People usually find the associations among test items based on properties of individual test items. This paper proposes a test item association model to represent the correlations of test item pairs by mining the response data of examinees. Then, a hypothesis test and an empirical analysis were used to verify and analyse the relationship between the test item correlation and similarity. Next, the effects of test item parameters on the correlation are investigated by applying the model to the simulated response data which are produced by Item Response Theory (IRT) simulation data generation software. Finally, three applications of this test item association model are listed. After verification, the proposed model can be used for precise teaching.
Plumage coloration and personality in early life: sexual differences in signalling
Authors: López‐Idiáquez David , Fargallo Juan Antonio , López‐Rull Isabel , Martínez‐Padilla Jesus
Published: September 2018

Several studies have shown that melanin‐based traits play a crucial role in social contexts as they are associated with dominance, personality and social behaviour. However, most of these studies have focused on adults, and the role of these traits in juveniles has rarely been explored. Here, we explore the association between two melanin‐based traits and nestling personality in Common KestrelsFalco tinnunculus. Our results show that female nestlings with blacker plumages displayed bolder personalities, providing evidence of sex‐dependent phenotypic integration of these two traits in males and females. We consider that this differential integration may arise from different selection pressures acting on males and females on plumage coloration during adulthood and that nestling coloration can act as a status signal within the juvenile age‐class.
Association of miR‐1247‐5p expression with clinicopathological parameters and prognosis in breast cancer
Authors: Zhang Peng , Fan Changsheng , Du Jun , Mo Xueli , Zhao Qikang
Published: September 2018

Our study aimed to clarify the correlation between miR‐1247‐5p expression and clinicopathological parameters and survival of patients with breast cancer (BC). We evaluated the expression level of miR‐1247‐5p in 224 formalin‐fixed, paraffin‐embedded specimens (112 BC and matched cancer free tissues) by quantitative real‐time reverse transcriptase polymerase chain reaction (qRT‐PCR). miR‐1247‐5p expression in BC tissues was found to be decreased compared with matched normal tissues (P < 0.01). Additionally, low miR‐1247‐5p expression in BC tissues was significantly associated with the advanced TNM stage (P = 0.007), lymph node metastasis (P = 0.015), poorer pathological differentiation (P = 0.005) and molecular subtype (P = 0.027). The patients in the low miR‐1247‐5p group had a shorter disease‐free survival and overall survival than those in the high miR‐1247‐5p group (P < 0.01). Furthermore, the univariate and the multivariate analyses showed that miR‐1247‐5p expression was an independent predictor of overall survival (P < 0.01). Our study showed that miR‐1247‐5p was related to the biological behaviour of breast tumour and prognosis of patients with BC. miR‐1247‐5p could be a novel tumour suppressor and act as a potential biomarker and therapeutic agent for breast carcinoma.
House Damage Revisited: How Type of Damage and Perpetrating Actor Affect Intentions and Actions of IDPs in Iraq
Authors: Aymerich Olga , Zeyneloglu Sinan
Published: September 2018

House damage has been a widespread consequence of the Islamic State (IS) crisis in Iraq. However, house and property damage per se is not a factor limiting return. The type and timing in which property destruction occurs – during direct military confrontation or before/after it – and the alleged perpetrator constitute better indicators of inhibited returns as type of damage and inflicting actor appear to have a significant effect on fears, perceptions and intentions of IDPs and returnees.
Microclimatic gradients provide evidence for a glacial refugium for temperate trees in a sheltered hilly landscape of Northern Italy
Authors: Gubler Moritz , Henne Paul D. , Schwörer Christoph , Boltshauser‐Kaltenrieder Petra , Lotter André F. , Brönnimann Stefan , Tinner Willy
Published: September 2018

Aim

Refugia play a key role in conserving biodiversity during periods of unfavourable and highly variable regional climate. However, refugial populations are often small and fragmented, which makes their identification difficult. In this study, we investigate whether an area of complex topography in the southern foreland of the Alps could have provided a suitable microclimate to serve as a glacial refugium for temperate trees during the last glacial.

Location

The Euganean Hills in Northern Italy (Veneto).

Methods

We assessed the current microclimatic variability in the ecologically diverse region on a fine scale by recording half‐hourly near‐surface temperatures over a period of 11 months. After comparing our measurements with today's vegetation distribution, broad‐scale synoptic patterns, and topoclimatic factors, we estimated refugial suitability based on extreme temperatures, climatic stability, and difference from the regional average.

Results

Present‐day temperature gradients within the Euganean Hills are large enough to explain the presence of the temperate tree species Fagus sylvatica as well as Mediterranean Quercus ilex, two species that are absent elsewhere in the adjacent Po Plain. During winter, anticyclonic weather patterns resulted in strong atmospheric inversions, with temperatures increasing by +1°C/100 m in the hills relative to the surrounding Po Plain.

Main conclusions

Our high‐resolution climate data support multi‐proxy palaeoecological records identifying the Euganean Hills as a refugium for temperate trees. Temperature anomalies of 2–4°C relative to the surrounding Po Plain are sufficient to allow several temperate tree species to survive the Last Glacial Maximum (LGM) in the Euganean Hills under a harsh continental climate. Specifically, elevations >200 m a.s.l. in the central parts of the hills may have provided suitable conditions for local LGM refugia. Regions of complex topography such as the Euganean Hills conserved past and present biodiversity and provide high‐priority areas for conservation under future climate warming.
Subjective Priors for Item Response Models: Application of Elicitation by Design
Authors: Ames Allison , Smith Elizabeth
Published: September 2018

Bayesian methods incorporate model parameter information prior to data collection. Eliciting information from content experts is an option, but has seen little implementation in Bayesian item response theory (IRT) modeling. This study aims to use ethical reasoning content experts to elicit prior information and incorporate this information into Markov Chain Monte Carlo (MCMC) estimation. A six‐step elicitation approach is followed, with relevant details at each stage for two IRT items parameters: difficulty and guessing. Results indicate that using content experts is the preferred approach, rather than noninformative priors, for both parameter types. The use of a noninformative prior for small samples provided dramatically different results when compared to results from content expert–elicited priors. The WAMBS (When to worry and how to Avoid the Misuse of Bayesian Statistics) checklist is used to aid in comparisons.
Promoting Stability for Youth Returning from Residential Care: Attorney Perspectives
Authors: Tyler Patrick M. , Trout Alexandra L. , Huscroft‐D'Angelo Jacqueline , Synhorst Lori L. , Lambert Matthew C.
Published: September 2018

Aftercare services have been suggested to improve reintegration for youth departing residential care programs. The purpose of this study was to collect views from legal professionals about the challenges youth and families face during reintegration and solutions to improve stability. Views were collected from 14 legal professionals (e.g., guardian ad litem, legal counsel) through a survey and 90‐minute nominal group technique focus group. Results indicated parent expectations about re‐entry and lack of services, supports and resources were challenges. Solutions suggested by participants included family, mental health and educational supports, and transition planning. Study limitations and future implications are discussed.
Potential Impact of Research on Adolescent Development on Juvenile Judge Decision‐making
Authors: Berryessa Colleen M.
Published: September 2018

This paper discusses how biological and psychological literature on the developmental differences between juveniles and adults may affect juvenile judges in their “dual role” as retributive and rehabilitative decision‐makers in juvenile cases, specifically focusing on sentencing. Particularly, it discusses potential influences of this research on adolescent development regarding four factors known to be integral in juvenile judge decision‐making: legal factors, characteristics of juvenile offenders, and individual structural and social contexts in which judges’ decisions are made. To conclude, implications and recommendations stemming from this discussion are considered.
“I Wanna Make My Mom Proud of Me”: Embracing Mothers as Protective Factors Against Future Offending in Delinquent Youth
Authors: VanderPyl Taryn
Published: September 2018

The potential protective factor of mothers is often overlooked in literature on juvenile delinquency. However, when hearing from incarcerated youth themselves, their mothers are a clear and unquestionable priority. Through embracing mothers using a strengths‐based lens, practitioners have an opportunity and responsibility to capitalize on this asset in a youth's life in an effort to aid rehabilitation and decrease recidivism. In this study, 1,008 writing samples from incarcerated youth were analyzed and writings to or about their mothers emerged prominently. Recommendations are shared on how to embrace and support mothers as protective factors against future offending among incarcerated youth.
Polarization and the growth of low‐skill service jobs in Spanish local labor markets
Authors: Consoli Davide , Sánchez‐Barrioluengo Mabel
Published: September 2018

This paper analyzes the long‐term transformations of the occupational structure in 50 provinces of Spain with a view to ascertain the existence and assess the extent of employment polarization. The peculiar characteristics of this country, namely rigid labor markets and the relatively recent transition to democracy, make for an interesting addition to existing studies on this topic. In line with previous literature on other countries, we find a strong association between the decline of “routine” mid‐skill jobs and the expansion of low‐skill service employment as well as differential labor market outcomes by levels of formal education. Results are robust to various controls and instrumental variables that account for long‐term industry specialization. We also find a positive local multiplier effect of high‐skilled workers on the demand for nontradable service jobs.
Effect of 5% transdermal lidocaine patches on postoperative analgesia in dogs undergoing hemilaminectomy
Authors: Re Bravo V. , Aprea F. , Bhalla R. J. , De Gennaro C. , Cherubini G. B. , Corletto F. , Vettorato E.
Published: September 2018

Objectives

To investigate the effect of 5% lidocaine patches on postoperative analgesia in dogs undergoing hemilaminectomy.

Materials and Methods

Client‐owned dogs undergoing hemilaminectomy for a single acute intervertebral thoracolumbar disc extrusion were enrolled in this prospective, randomised, blinded clinical trial. Following methadone administration, anaesthesia was induced with propofol, and maintained with isoflurane in oxygen and fentanyl infusion, in both groups. After skin closure, two 1∙5 cm wide 5% lidocaine patch strips were attached along both sides of the wound in dogs allocated to Group L. In Group C, the two lidocaine patch strips were applied but the transparent isolating liner was not removed. Postoperatively, all dogs received a non‐steroidal anti‐inflammatory drug, gabapentin and diazepam. Methadone was administered according to the short form of Glasgow Composite Pain Scale with pain assessed every 2 hours for 48 hours by observers unaware of the treatment.

Results

Thirty‐nine dogs completed the study. Demographic data, end‐expiratory fraction of isoflurane, fentanyl consumption, anaesthesia and surgical times were similar between groups. The number of dogs requiring postoperative methadone and the number of doses of methadone administered were not different between groups. No macroscopic skin reaction was noticed once the patches were removed.

Clinical Significance

In this setting, 5% lidocaine patches did not provide additional postoperative analgesia in dogs undergoing hemilaminectomy.
Generalist haemosporidian parasites are better adapted to a subset of host species in a multiple host community
Authors: Huang Xi , Ellis Vincenzo A. , Jönsson Jane , Bensch Staffan
Published: September 2018

Parasites that can infect multiple host species are considered to be host generalists with low host specificity. However, whether generalist parasites are better adapted to a subset of their host species remains unknown. To elucidate this possibility, we compared the variation in prevalence and infection intensity among host species of three generalist parasite lineages belonging to the morphological species Haemoproteus majoris, in a natural bird community in southern Sweden. Prevalence in each host species was confirmed by nested PCR and DNA sequencing, and infection intensities were quantified using lineage‐specific real‐time qPCR. For two of the three lineages, we detected positive correlations between prevalence and infection intensity, indicating that these generalist parasites are better adapted to a subset of host species, which may have been more frequently encountered during the evolution of the parasite; we refer to these as main host species. For both lineages, the main host species were more phylogenetically related than expected by chance as revealed by strong phylogenetic signal in prevalence among hosts. By comparing our results with previous records of these parasites, we found that the host range of a generalist parasite can vary among different communities and may partly be shaped by the presence of other parasites. Our study reveals that generalist parasites may be specialized on a subset of their host species and it highlights the importance of considering infection intensity and host phylogeny when determining the host specificity of a parasite.
Functional erythropoietin‐hepcidin axis in recombinant human erythropoietin independent haemodialysis patients
Authors: Touzot Maxime , Lefebvre Thibaud , Roux Arthur , Maheas Catherine , Ridel Christophe , Puy Hervé , Karim Zoubida
Published: September 2018

Aim

Relatively few haemodialysis (HD) patients remain independent of recombinant human erythropoietin (‘rHU‐EPO free patients’). We investigated the role of EPO and hepcidin, two key hormones involved in anaemia.

Methods

We report a monocentric case‐control series. Iron status, EPO and hepcidin levels were analysed in 15 Adult HD (Age > 18 years) with a stable haemoglobin (Hb) level that have not received rHU‐EPO for at least 6 months (=rHU‐EPO free patients); and in 60 controls with a stable rHU‐EPO dose and Hb level.

Results

The rHU‐EPO free patients had a higher Hb level compared to controls (12.1 ± 0.99 g/dL vs 11.1 ± 0.73, P = 0.0014), and a lower ferritin level (183 ± 102 vs 312 ± 166 ng/mL, P = 0.001). Hepcidin levels were lower in the rHU‐EPO free patients (12.53 ± 10.46 ng/mL) compared to the controls (37.95 ± 34.33 ng/mL), P = 0.0033. Hepcidin levels correlated significantly with ferritin levels; but neither with transferrin saturation, C‐reactive protein nor EPO levels. Unsupervised analysis revealed that rHU‐EPO free patients had a specific clinical/biological profile (presence of renal cyst, longer dialysis vintage, lower ferritin, and EPO and hepcidin levels compared to the control group). Finally, we showed that a lower ferritin level might be a surrogate marker of a lower hepcidin status in this population.

Conclusion

Recombinant human erythropoietin free patients seem to restore the EPO‐hepcidin axis that is critical for erythropoiesis. A specific combination of clinical and biological parameters may help to detect future rHU‐EPO free patients.
Allele‐specific analysis of single parent backcross population identifies HOX10 transcription factor as a candidate gene regulating rice root growth
Authors: Reddy Sowmya H. , Kambalimath Sumanth K. , Singhal Rajesh K. , Chikkakariyappa Manjunath K. , Muthurajan Raveendran , Rajanna Mavinahalli P. , Sreevathsa Rohini , Sevanthi Amitha M. , Mohapatra Trilochan , Sarla Neelamraju , Chinnusamy Viswanathan , Krishnan Gopala S. , Singh Ashok K. , Singh Nagendra K. , Sharma Rameshwar P. , Sheshshayee Sreeman M.
Published: September 2018

Understanding the molecular and physiological mechanisms of trait diversity is crucial for crop improvement to achieve drought adaptation. Root traits such as high biomass and/or deep rootedness are undoubtedly important drought adaptive traits. The major aim of this investigation was to functionally characterize a set of ethyl methane sulfonate‐induced rice mutants for root traits. We report the identification of a high‐root biomass mutant through a novel screening strategy for yield and Δ13C measurements. The high‐root mutant (392‐9‐1) thus identified, had a 66% higher root biomass compared to wild‐type (Nagina‐22). Better maintenance of leaf turgor and carbon assimilation rates resulted in lower drought susceptibility index in 392‐9‐1. Targeted resequencing revealed three non‐synonymous single nucleotide variations in 392‐9‐1 for the genes HOX10, CITRATE SYNTHASE and ZEAXANTHIN EPOXIDASE. Segregation pattern of phenotype and mutant alleles in a single parent backcross F2 population revealed a typical 3:1 segregation for each of the mutant alleles. The number of F2 progeny with root biomass equal to or greater than that of 392‐9‐1 represented approximately one‐third of the population indicating a major role played by HOX10 gene in regulating root growth in rice. Allele‐specific Sanger sequencing in contrasting F2 progenies confirmed the co‐segregation of HOX10 allele with the root biomass. The non‐synonymous mutations in the other two genes did not reveal any specific pattern of co‐segregation with root phenotype, indicating a strong role of HOX10, an upstream transcription factor, in regulating root biomass in rice.
Understanding the ASEAN way of regional qualification governance: The case of mutual recognition agreements in the professional service sector
Authors: Hamanaka Shintaro , Jusoh Sufian
Published: September 2018

Existing studies on Mutual Recognition Agreements (MRAs) are mostly based on the European experience. In this paper, we discuss the ongoing attempt of the Association of Southeast Asian Nations (ASEAN) to establish very unique MRAs, using professional service qualifications, particularly engineering, as a case study. Several ASEAN professional service qualification MRAs employ a “hub‐and spoke” model, wherein neither the hub (regional mechanism) nor the spokes (national authorities) are more powerful than the other. This model features both harmonization of professional qualifications led by regional mechanisms and the recognition of partner countries’ qualifications granted by national authorities. Why does ASEAN need unique MRA governance that features both harmonization and mutual recognition? We find several valid practical explanations, such as limitations of supranational power, confidence building among members, and capacity development. More fundamentally, neither simple harmonization nor simple mutual recognition functions well in ASEAN, where three types of gaps exist among member states. The diversity in legal backgrounds suggests that the combination of harmonization preferred by civil law countries and mutual recognition preferred by common law countries is suitable. The variety in social norms ranging from market mechanisms to social safety implies that the combination of harmonization and mutual recognition is also suitable. Gaps in the price and quality of professional services across ASEAN member states requires the unique approach to facilitate and control the movement of professionals and to promote the joint practice between foreign and local professionals in both high and low income countries to create a win‐win situation.
Millikan, Meaning, and Minimalism
Authors: Borg Emma
Published: September 2018

Across a series of seminal works, Ruth Millikan has produced a compelling and comprehensive naturalized account of content. With respect to linguistic meaning, her ground‐breaking approach has been to analyse the meaning of a linguistic term via the function it performs which has been responsible for securing the term's survival. This way of looking at things has significant repercussions for a number of recent debates in philosophy of language. This article explores these repercussions through the lens of what is known as semantic minimalism, using the tenets of minimalism to draw out some questions for Millikan's approach to the semantics/pragmatics divide.
Increased human stretch reflex dynamic sensitivity with height‐induced postural threat
Authors: Horslen Brian C. , Zaback Martin , Inglis J. Timothy , Blouin Jean‐Sébastien , Carpenter Mark G.
Published: September 2018

Key points

Threats to standing balance (postural threat) are known to facilitate soleus tendon‐tap reflexes, yet the mechanisms driving reflex changes are unknown.

Scaling of ramp‐and‐hold dorsiflexion stretch reflexes to stretch velocity and amplitude were examined as indirect measures of changes to muscle spindle dynamic and static function with height‐induced postural threat.

Overall, stretch reflexes were larger with threat. Furthermore, the slope (gain) of the stretch‐velocity vs. short‐latency reflex amplitude relationship was increased with threat.

These findings are interpreted as indirect evidence for increased muscle spindle dynamic sensitivity, independent of changes in background muscle activity levels, with a threat to standing balance.

We argue that context‐dependent scaling of stretch reflexes forms part of a multisensory tuning process where acquisition and/or processing of balance‐relevant sensory information is continuously primed to facilitate feedback control of standing balance in challenging balance scenarios.

Postural threat increases soleus tendon‐tap (t‐) reflexes. However, it is not known whether t‐reflex changes are a result of central modulation, altered muscle spindle dynamic sensitivity or combined spindle static and dynamic sensitization. Ramp‐and‐hold dorsiflexion stretches of varying velocities and amplitudes were used to examine velocity‐ and amplitude‐dependent scaling of short‐ (SLR) and medium‐latency (MLR) stretch reflexes as an indirect indicator of spindle sensitivity. t‐reflexes were also performed to replicate previous work. In the present study, we examined the effects of postural threat on SLR, MLR and t‐reflex amplitude, as well as SLR‐stretch velocity scaling. Forty young‐healthy adults stood with one foot on a servo‐controlled tilting platform and the other on a stable surface. The platform was positioned on a hydraulic lift. Threat was manipulated by having participants stand in low (height 1.1 m; away from edge) then high (height 3.5 m; at the edge) threat conditions. Soleus stretch reflexes were recorded with surface electromyography and SLRs and MLRs were probed with fixed‐amplitude variable‐velocity stretches. t‐reflexes were evoked with Achilles tendon taps using a linear motor. SLR, MLR and t‐reflexes were 11%, 9.5% and 16.9% larger, respectively, in the high compared to low threat condition. In 22 out of 40 participants, SLR amplitude was correlated to stretch velocity at both threat levels. In these participants, the gain of the SLR–velocity relationship was increased by 36.1% with high postural threat. These findings provide new supportive evidence for increased muscle spindle dynamic sensitivity with postural threat and provide further support for the context‐dependent modulation of human somatosensory pathways.
In vivo evidence for reduced ion channel expression in motor axons of patients with amyotrophic lateral sclerosis
Authors: Howells James , Matamala José Manuel , Park Susanna B. , Garg Nidhi , Vucic Steve , Bostock Hugh , Burke David , Kiernan Matthew C.
Published: September 2018

Key points

The progressive loss of motor units in amyotrophic lateral sclerosis (ALS) is initially compensated for by the reinnervation of denervated muscle fibres by surviving motor axons.

A disruption in protein homeostasis is thought to play a critical role in the pathogenesis of ALS.

The changes in surviving motor neurons were studied by comparing the nerve excitability properties of moderately and severely affected single motor axons from patients with ALS with those from single motor axons in control subjects.

A mathematical model indicated that approximately 99% of the differences between the ALS and control units could be explained by a non‐selective reduction in the expression of all ion channels.

These changes in ALS patients are best explained by a failure in the supply of ion channel and other membrane proteins from the diseased motor neuron.

Amyotrophic lateral sclerosis (ALS) is characterised by a progressive loss of motor units and the reinnervation of denervated muscle fibres by surviving motor axons. This reinnervation preserves muscle function until symptom onset, when some 60–80% of motor units have been lost. We have studied the changes in surviving motor neurons by comparing the nerve excitability properties of 31 single motor axons from patients with ALS with those from 21 single motor axons in control subjects. ALS motor axons were classified as coming from moderately or severely affected muscles according to the compound muscle action potential amplitude of the parent muscle. Compared with control units, thresholds were increased, and there was reduced inward and outward rectification and greater superexcitability following a conditioning impulse. These abnormalities were greater in axons from severely affected muscles, and were correlated with loss of fine motor skills. A mathematical model indicated that 99.1% of the differences between the moderately affected ALS and control units could be explained by a reduction in the expression of all ion channels. For the severely affected units, modelling required, in addition, an increase in the current leak through and under the myelin sheath. This might be expected if the anchoring proteins responsible for the paranodal seal were reduced. We conclude that changes in axonal excitability identified in ALS patients are best explained by a failure in the supply of ion channel and other membrane proteins from the diseased motor neuron, a conclusion consistent with recent animal and in vitro human data.
Feedforward‐ and motor effort‐dependent increase in prefrontal oxygenation during voluntary one‐armed cranking
Authors: Ishii Kei , Liang Nan , Asahara Ryota , Takahashi Makoto , Matsukawa Kanji
Published: September 2018

Key points

Some cortical areas are believed to transmit a descending signal in association with motor intention and/or effort that regulates the cardiovascular system during exercise (termed central command). However, there was no evidence for the specific cortical area responding prior to arbitrary motor execution and in proportion to the motor effort.

Using a multichannel near‐infrared spectroscopy system, we found that the oxygenation of the dorsolateral and ventrolateral prefrontal cortices on the right side increases in a feedforward‐ and motor effort‐dependent manner during voluntary one‐armed cranking with the right arm.

This finding may suggest a role of the dorsolateral and ventrolateral prefrontal cortices in triggering off central command and may help us to understand impaired regulation of the cardiovascular system in association with lesion of the prefrontal cortex.

Output from higher brain centres (termed central command) regulates the cardiovascular system during exercise in a feedforward‐ and motor effort‐dependent manner. This study aimed to determine a cortical area responding prior to arbitrarily started exercise and in proportion to the effort during exercise. The oxygenation responses in the frontal and frontoparietal areas during one‐armed cranking with the right arm were measured using multichannel near‐infrared spectroscopy, as indexes of regional blood flow responses, in 20 subjects. The intensity of voluntary exercise was 30% and 60% of the maximal voluntary effort (MVE). At the start period of both voluntary cranking tasks, the oxygenation increased (P < 0.05) only in the lateral and dorsal part of the dorsolateral prefrontal cortex (DLPFC), ventrolateral prefrontal cortex (VLPFC) and sensorimotor cortices. Then, the oxygenation increased gradually in all cortical areas during cranking at 60% MVE, while oxygenation increased only in the frontoparietal area and some of the frontal area during cranking at 30% MVE. The rating of perceived exertion to the cranking tasks correlated (P < 0.05) with the oxygenation responses on the right side of the lateral‐DLPFC (r = 0.46) and VLPFC (r = 0.48) and the frontopolar areas (r = 0.47–0.49). Motor‐driven passive one‐armed cranking decreased the oxygenation in most cortical areas, except the contralateral frontoparietal areas. Accordingly, the lateral‐DLPFC and VLPFC on the right side would respond in a feedforward‐ and motor effort‐dependent manner during voluntary exercise with the right arm. Afferent inputs from mechanosensitive afferents may decrease the cortical oxygenation.
Calibration of HPGe Detector Efficiencies With Self-Absorption Correction of Gas Sphere Sources
Authors: Khan Waseem , He Chaohui
Published: September 2018

Several types of radioactive gases are released from the nuclear reactor. In order to measure the activity of such gases, it is necessary to calculate the accurate efficiency. Practically, efficiency calibration with gaseous sources is not very easy because of the low half-lives of the noble gases. For this purpose, Monte Carlo (MC) simulation was performed to study the full energy peak efficiency of two n-type high-purity Germanium (HPGe) detectors. Two spheres of xenon and krypton composition sources with two nuclides (Xe133 and Kr85) and two-point sources were simulated, covering the energy range from 81 keV to 604 keV. Self-absorption correction factors were calculated with GEANT4 for two gas sphere samples and obtained good efficiency agreement with the experimental results. The simulation was performed for various gas samples with different densities and observed their effects on the full energy peak efficiency value of two detectors. The corresponding self-absorption correction factors were calculated for each gaseous sample and investigated that the self-absorption correction factors not only depend on the sample characteristics but also on the detector geometry and source to detector distance. The dependence of the full energy peak efficiency on the side cap wall material and their thicknesses were also carried out for some particular photon energies.
Endwall
Film Cooling Performance for a First-Stage Guide Vane With Upstream Combustor Walls and Inlet
Injection
Authors: Yang Xing , Liu Zhao , Liu Zhansheng , Simon Terrence , Feng Zhenping
Published: September 2018

Effects of an upstream combustor wall on turbine nozzle endwall film cooling performance are numerically examined in a linear cascade in this paper. Film cooling is by two rows of cooling holes at 20% of the axial chord length upstream of the vane leading edge (LE) plane. The combustor walls are modeled as flat plates with square trailing edges (TE) positioned upstream of the endwall film cooling holes. A combustor wall is in line with the LE of every second vane. The influence of the combustor wall, when shifted in the axial and tangential directions, is investigated to determine effects on passage endwall cooling for three representative film cooling blowing ratios. The results show how shed vortices from the combustor wall greatly alter the flow field near the cooling holes and inside the vane passage. Film cooling distribution patterns, particularly in the entry region and along the pressure side of the passage, are affected. The combustor wall leads to an imbalance in film cooling distribution over the endwalls for adjacent vane passages. Results show a larger effect of tangential shift of the combustor wall on endwall cooling effectiveness than the effect of an equal axial shift. The study provides guidance regarding design of combustor-to-turbine transition ducts.
Evaluation of a Diffusion Coefficient Based on Proper Solution Space
Authors: Wang Yuanlong , Hamad Abdalkaleg , Tadi Mohsen
Published: September 2018

This note is concerned with the evaluation of the unknown diffusion coefficient in a steady-state heat conduction problem. The proposed method is iterative and, starting with an initial guess, updates the assumed value at every iteration. The updating stage is achieved by generating a set of functions that satisfy some of the required boundary conditions. The correction to the assumed value is then computed by imposing the remaining boundary conditions. Numerical examples are used to study the applicability of this method.
Investigating the Mixing Efficiencies of Liquid-to-Liquid Chemical Injection Manifolds for Aquatic Invasive Species Management
Authors: Zolper Thomas J. , Cupp Aaron R. , Smith David L.
Published: September 2018

Aquatic invasive species (AIS) have spread throughout the United States via major rivers and tributaries. Locks and dams positioned along affected waterways, specifically lock chambers, are being evaluated as potential management sites to prevent further expansion into new areas. Recent research has shown that infusion of chemicals (e.g., carbon dioxide) into water can block or kill several invasive organisms and could be a viable option at navigational structures such as lock chambers because chemical infusion would not interfere with vessel passage or lock operation. Chemical treatments near lock structures will require large-scale fluid-mechanic systems and significant energy. Mixing must extend to all stagnation regions within a lock structure to prevent the passage of an invasive fish. This work describes the performance of both wall- and floor-based CO2-infused-water to water injection manifolds targeted for lock structures in terms of mixing time, mixing homogeneity, injection efficiency, and operational power requirements. Both systems have strengths and weaknesses so selection recommendations are given for applications such as open systems and closed systems.
Specimen Thickness Dependency of Energy Release Rate of a Gelatin Hydrogel and Glass Substrate Interface
Authors: Thakre Avinash A. , Singh Arun K.
Published: September 2018

Soft solids, such as rubbers, elastomers, and gels, are the important polymeric materials. A better understanding of their interfacial properties such as friction and adhesion is critical for variety of technological applications. Motivated by the experimental observation that interfacial properties can be modified even without changing the content of a soft solid, the effect of specimen thickness on the energy release rate (G) of a soft gelatin hydrogel is investigated in direct shear test. Slide-hold-slide (SHS) experiments have shown that shear strength decreases, while corresponding crack length increases, with increase in thickness of gel specimens. However, G at static, dynamic and residual strengths increase with specimen thickness. At the end, these observations are explained in light of mixed mode I/II fracture and shear rate effects at the sliding interface.
Nanoscratch Resistance and Nanotribological Performance of Ti/MoS2 Coating on Al-Si Alloy Deposited by Pulse Laser Deposition Technique
Authors: Banday Summera , Wani M. F.
Published: September 2018

Ti/MoS2 coating was deposited by pulse laser deposition technology on Al-Si substrate. The microstructure, elemental analysis, nanotribological behavior of coating was investigated. The coating was composed of Ti, Mo, S, and O with typical diffraction peak around 2θ range from 30 deg to 70 deg. Nanoscratch with ramp loading was performed at low loads. The scratch test with ramp normal loading was analyzed for failure of coating in three ranges, viz., range A, range B, and range C. Scratch test result shows that the peeling of coating occurred at the normal load of 1327.75 μN and the lateral load of 75.96 μN. Nanowear with 2, 4, 6, 8, 10 number of cycles was performed at low load 100 μN. Nanowear results shows that wear rate decreases with increase in wear cycles, which attributed the self-lubricating property of Ti/MoS2 coating. Also, Ti/MoS2 coating display smooth wear path with no debris and cracks, which attributed plastic flow of coating around impression. Thus, mode of wear mechanism is mainly ductile and abrasive.
Experiment-Based Motion Reconstruction and Restitution Coefficient Estimation of a Vibro-Impact System
Authors: Li Tao , Seguy Sébastien , Lamarque Claude-Henri , Berlioz Alain
Published: September 2018

The objective of this paper is to demonstrate the motion reconstruction and the parameter estimation of a vibro-impact (VI) system from limited experimental information. Based on the measured displacement and acceleration of its linear main system, the rest motion information such as the displacement and velocity of the attached VI energy sink can be calculated rather than difficult direct measurement, and therefore, different response regimes from the strongly modulated response to the classic regime with two impacts per cycle are reconstructed. Consequently, it provides comprehensive experimental data for the validation of analytical and numerical results and for any experimental bifurcation analysis. Moreover, a procedure to estimate the restitution coefficient from periodic impacts is demonstrated. This new experimental approach to estimate the value of the restitution coefficient is simple and this accurate value could play an important role in analytical and numerical study.
Statistical Assessment and Validation of Experimental and Computational Ship Response in Irregular Waves
Authors: Diez Matteo , Broglia Riccardo , Durante Danilo , Olivieri Angelo , Campana Emilio F. , Stern Frederick
Published: September 2018

The objective of this work is to provide and use both experimental fluid dynamics (EFD) data and computational fluid dynamics (CFD) results to validate a regular-wave uncertainty quantification (UQ) model of ship response in irregular waves, based on a set of stochastic regular waves with variable frequency. As a secondary objective, preliminary statistical studies are required to assess EFD and CFD irregular wave errors and uncertainties versus theoretical values and evaluate EFD and CFD resistance and motions uncertainties and, in the latter case, errors versus EFD values. UQ methods include analysis of the autocovariance matrix and block-bootstrap of time series values (primary variable). Additionally, the height (secondary variable) associated with the mean-crossing period is assessed by the bootstrap method. Errors and confidence intervals of statistical estimators are used to define validation criteria. The application is a two-degrees-of-freedom (heave and pitch) towed Delft catamaran with a length between perpendiculars equal to 3 m (scale factor equal to 33), sailing at Froude number equal to 0.425 in head waves at scaled sea state 5. Validation variables are x-force, heave and pitch motions, vertical acceleration of bridge, and vertical velocity of flight deck. Autocovariance and block-bootstrap methods for primary variables provide consistent and complementary results; the autocovariance is used to assess the uncertainty associated with expected values and standard deviations and is able to identify undesired self-repetition in the irregular wave signal; block-bootstrap methods are used to assess additional statistical estimators such as mode and quantiles. Secondary variables are used for an additional assessment of the quality of experimental and simulation data as they are generally more difficult to model and predict than primary variables. Finally, the regular wave UQ model provides a good approximation of the desired irregular wave statistics, with average errors smaller than 5% and validation uncertainties close to 10%.
Numerical Optimization, Characterization, and Experimental Investigation of Additively Manufactured Communicating Microchannels
Authors: Kirsch Kathryn L. , Thole Karen A.
Published: September 2018

The degree of complexity in internal cooling designs is tied to the capabilities of the manufacturing process. Additive manufacturing grants designers increased freedom while offering adequate reproducibility of micro-sized, unconventional features that can be used to cool the skin of gas turbine components. One such desirable feature can be sourced from nature; a common characteristic of natural transport systems is a network of communicating channels.

In an effort to create an engineered design that utilizes the benefits of those natural systems, the current study presents wavy microchannels that were connected using branches. Two different wavelength baseline configurations were designed, then each were numerically optimized using a commercial adjoint-based method. Three objective functions were posed to (1) minimize pressure loss, (2) maximize heat transfer, and (3) maximize the ratio of heat transfer to pressure loss. All baseline and optimized microchannels were manufactured using Laser Powder Bed Fusion for experimental investigation; pressure loss and heat transfer data were collected over a range of Reynolds numbers.

The additive manufacturing process reproduced the desired optimized geometries faithfully. Surface roughness, however, strongly influenced the experimental results; successful replication of the intended flow and heat transfer performance was tied to the optimized design intent. Even still, certain test coupons yielded performances that correlated well with the simulation results.
A Reduced Order Model for Predicting Hot-Gas Ingestion Into the Wheelspace of Gas Turbines
Authors: Pardeshi Irsha , Liu Jason , Shih Tom I-P.
Published: September 2018

In gas turbines, pressure variations induced by the rotor’s rotation and created by the stator and rotor-stator interactions cause hot gas to enter into the wheelspace (i.e., the region between the stator and rotor disks). Purge flow is used to prevent the hot gas from entering, and rim seals are used to minimize the amount of purge flow needed. Preventing hot-gas ingestion is essential to protect the structural integrity of the rotor and stator disks.

In this study, a reduced-order model is developed to predict hot-gas ingestion for a given purge flow and for an axial and a radial rim seal and to guide the design of rim seals. The model developed is semi-empirical — utilizing available data in the literature and recognizing certain trends and universal properties in the data if proper dimensionless parameters are used. The model has the advantage of only requiring the following inputs to make predictions: rotor’s rotation speed, flow rate in the turbine’s hot-gas path, purge flow rate, and dimensions of the seal and the wheelspace. Thus, this model differs from existing models in that an experimental input on parameters such as discharge coefficient, minimum sealing flow rate, or mixing length across the rim seal are not needed.

The model developed was assessed by using it to predict hot-gas ingestion for a range of purge flow rates (0 to minimum needed to prevent ingestion), rotor speeds (2,000 to 3,500 rpm), and dimensions of the seal geometries (amount of overlap in the seal and width of the flow path through the seal) and then comparing the prediction with experimental data not used in the creation of the model.
Experimental and Numerical Investigations on Leakage Flow Characteristics of Two Kinds of Brush Seals
Authors: Zhang Yuanqiao , Li Jun , Yan Xin , Li Zhigang
Published: September 2018

The leakage characteristics of interference and clearance brush seals were experimentally measured and numerically simulated in this paper. The leakage coefficients of the brush seals without a deflector plate at different pressure differentials were firstly measured. The effect of deflector plate and clearance on seal performance and the detailed flow field of the brush seal were numerically investigated using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) solutions coupled with a Non-Darcian Porous Medium model. In addition, this study experimentally investigated the hysteresis characteristic of interference and clearance brush seals without deflector plates, and presented detailed investigations on the blow down effect of clearance brush seal using Computational Fluid Dynamics (CFD) as mentioned above and Finite Element Method (FEM) approaches. The obtained results show that the leakage coefficient and blow-down effect of the brush seal with a deflector plate is lower than that of the brush seal without a deflector plate at the same pressure difference and the clearance between the bristle pack and shaft will increase the leakage coefficient significantly. The different hysteresis characteristics of interference and clearance brush seals are illustrated and discussed.