bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating characteristics of collaboration between nurse practitioners and medical practitioners in primary healthcare: a mixed methods multiple case study protocol
Authors: Schadewaldt Verena , McInnes Elizabeth , Hiller Janet E. , Gardner Anne
Published: October 2013

Aim

To investigate characteristics of collaboration between nurse practitioners and medical practitioners in the primary healthcare setting in Australia.

Background

Recent definitions of collaboration in the literature describe it as being based on communication, shared decision‐making and the respect and equality of team members. However, research demonstrates a tension between this theoretical ideal and how collaboration between nurse practitioners and medical practitioners occurs in practice. Different socialization processes of the two professions and legislative requirements influence collaborative practice. The way these two professions overcome traditional boundaries and realize collaborative practice in the primary healthcare setting needs to be examined.

Design

Mixed methods multiple case study including up to six sites with a minimum of six and a maximum of 20 participants in total.

Methods

Data on collaborative practice between nurse practitioners and medical practitioners in primary health care will be collected in three phases: (1) two‐week direct observation in the practice setting to capture actual behaviour and context; (2) questionnaire to measure dimensions of collaboration; and (3) one‐to‐one semi‐structured interviews with nurse practitioners, medical practitioners and practice managers to record experiences, perceptions and understanding of collaboration.

Discussion

Triangulation of findings will generate a comprehensive understanding of how collaboration between nurse practitioners and medical practitioners in Australia occurs in the primary care setting. The results of this study will inform nurse practitioners, medical practitioners practice managers and policy makers on successful models of collaboration.
Agronomic Water Mass Balance vs. Well Measurement for Assessing Ogallala Aquifer Depletion in the Texas Panhandle
Authors: Ouapo Constant Z. , Stewart B.A. , DeOtte Robert E.
Published: October 2013

The Ogallala Aquifer is depleting faster than it is being replenished. Interpretation of well data suggests that the water table in some counties is not declining, or not as much as might be expected in view of the amount of land being irrigated. As the Ogallala Aquifer in the Texas Panhandle receives almost no recharge, a possible explanation is that the current method of using well data for estimating the quantity of water remaining in the aquifer is underestimating water in storage. This study used an agronomic water mass balance approach to estimate how much water has been used for irrigation compared to amounts estimated by well data. The major finding was in counties where irrigation well capacities have declined significantly but irrigation is continuing, there is likely more water in storage than presently estimated, but the amounts of water being used for irrigation in those counties are greater than estimated changes of water in storage. The proposed hypothesis for this difference is there are mounds of water between wells that are not being accounted for and data are presented and discussed to support this conjecture.
Heparin‐binding epidermal growth factor‐like growth factor: A hepatic stellate cell proliferation inducer via ErbB receptors
Authors: Zhang Di , Zhang Jian , Jiang Xiaoyu , Li Xiaojun , Wang Yan , Ma Junji , Jiang Huiqing
Published: October 2013

Background and Aim

Heparin‐binding epidermal growth factor‐like growth factor (HB‐EGF) has a proliferative effect on several types of cells. However, the role of HB‐EGF on hepatic stellate cells (HSCs) is not clear. The present study is to investigate the regulatory effects of HB‐EGF on HSC proliferation and apoptosis.

Methods

Activated primary rat HSCs and two HSC cell lines (human LX2 and rat T6) were used in this study. Four inhibitors (CRM197 to HB‐EGF, AG1478 to epidermal growth factor receptor [EGFR], PD98059 to mitogen‐activated kinase, and LY294002 to phosphatidylinositol 3‐kinase) were employed to verify the pathway of HB‐EGF on cell proliferation and apoptosis.

Results

HB‐EGF expression was significantly increased in activated HSCs. HB‐EGF increased the expressions of phospho‐EGFR and ErbB4 receptors, the phosphorylation of extracellular signal‐regulated kinase (ERK) and Akt. Consequently, HB‐EGF stimulated HSC proliferation and suppressed HSC apoptosis. Each individual inhibitor specifically inhibited the correlated receptor or enzyme and inhibited HSC proliferation and induced its apoptosis.

Conclusions

HB‐EGF promotes HSC proliferation via activation of the EGFR and ErbB4 receptors and, subsequently, via activation of ERK and Akt. Any blockage in the chain obstructs the flow from HB‐EGF to HSC proliferation. Therefore, HB‐EGF is a potential therapeutic target in liver fibrosis.
Pre‐S mutations of hepatitis B virus affect genome replication and expression of surface antigens
Authors: Kim Beom Kyung , Choi Sung Hoon , Ahn Sung Hyun , Chung Ae Ri , Park Yong Kwang , Han Kwang‐Hyub , Kim Seungtaek , Kim Hyon‐Suk , Park Jeon Han , Kim Kyung Sik , Lee Hee Seung , Cho Yong Sang , Kim Kyun‐Hwan , Ahn Sang Hoon
Published: October 2013

Backgrounds and Aims

In chronic hepatitis B virus (HBV) infection, quantitative HBV surface antigen (qHBsAg) is useful for monitoring viral replication and treatment responses. We aimed to determine whether pre‐S mutations have any effect on circulating qHBsAg.

Methods

Plasmids expressing 1–8 amino acid deletion in pre‐S1 (“pre‐S1Δ1‐8”) and 3‐25 amino acid deletion in pre‐S2 (“pre‐S2Δ3‐25”) were constructed. At 72 h post‐transfection into Huh7 cells, qHBsAg were measured using electrochemiluminescence immunoassay analyzer. To mimic milieus of quasispecies, we co‐transfected either pre‐S1Δ1‐8 or pre‐S2Δ3‐25 with wild type (WT).

Results

Pre‐S mutations affected transcription and replication ability of HBV because of altered overlapping polymerase. Compared with WT, extracellular qHBsAg in pre‐S1Δ1‐8 and pre‐S2Δ3‐25 were on average 3.87‐fold higher and 0.92‐fold lower, respectively, whereas intracellular qHBsAg in pre‐S1Δ1‐8 and pre‐S2Δ3‐25 were 0.57‐fold lower and 1.60‐fold higher, respectively. Immunofluorescence staining of cellular HBsAg showed that pre‐S1Δ1‐8 had less staining and that pre‐S2Δ3‐25 had denser staining. As ratios of either pre‐S1Δ1‐8 or pre‐S2Δ3‐25:WT increased from 0:10 to 10:0 gradually, relative extracellular qHBsAg increased from 1.0 to 3.85 in pre‐S1Δ1‐8 co‐transfection, whereas those decreased from 1.0 to 0.88 in pre‐S2Δ3‐25 co‐transfection.

Conclusion

Pre‐S mutations exhibit different phenotypes of genome replication and HBsAg expression according to their locations. Thus, qHBsAg level for diagnosis and prognostification in chronic HBV infection should be used more cautiously, considering emergences of pre‐S deletion mutants.
Identification and expression profiling of Vigna mungo microRNAs from leaf small RNA transcriptome by deep sequencing
Authors: Paul Sujay , Kundu Anirban , Pal Amita
Published: October 2013

MicroRNAs (miRNAs) represent a class of small non‐coding RNA molecules that play a crucial role in post‐transcriptional gene regulation. Several conserved and species‐specific miRNAs have been characterized to date, predominantly from the plant species whose genome is well characterized. However, information on the variability of these regulatory RNAs in economically important but genetically less characterized crop species are limited. Vigna mungo is an important grain legume, which is grown primarily for its protein‐rich edible seeds. miRNAs from this species have not been identified to date due to lack of genome sequence information. To identify miRNAs from V. mungo, a small RNA library was constructed from young leaves. High‐throughput Illumina sequencing technology and bioinformatic analysis of the small RNA reads led to the identification of 66 miRNA loci represented by 45 conserved miRNAs belonging to 19 families and eight non‐conserved miRNAs belonging to seven families. Besides, 13 novel miRNA candidates in V. mungo were also identified. Expression patterns of selected conserved, non‐conserved, and novel miRNA candidates have been demonstrated in leaf, stem, and root tissues by quantitative polymerase chain reaction, and potential target genes were predicted for most of the conserved miRNAs. This information offers genomic resources for better understanding of miRNA mediated post‐transcriptional gene regulation.
Genomic regions underlying agronomic traits in linseed (Linum usitatissimum L.) as revealed by association mapping
Authors: Soto‐Cerda Braulio J. , Duguid Scott , Booker Helen , Rowland Gordon , Diederichsen Axel , Cloutier Sylvie
Published: October 2013

The extreme climate of the Canadian Prairies poses a major challenge to improve yield. Although it is possible to breed for yield per se, focusing on yield‐related traits could be advantageous because of their simpler genetic architecture. The Canadian flax core collection of 390 accessions was genotyped with 464 simple sequence repeat markers, and phenotypic data for nine agronomic traits including yield, bolls per area, 1,000 seed weight, seeds per boll, start of flowering, end of flowering, plant height, plant branching, and lodging collected from up to eight environments was used for association mapping. Based on a mixed model (principal component analysis (PCA) + kinship matrix (K)), 12 significant marker‐trait associations for six agronomic traits were identified. Most of the associations were stable across environments as revealed by multivariate analyses. Statistical simulation for five markers associated with 1000 seed weight indicated that the favorable alleles have additive effects. None of the modern cultivars carried the five favorable alleles and the maximum number of four observed in any accessions was mostly in breeding lines. Our results confirmed the complex genetic architecture of yield‐related traits and the inherent difficulties associated with their identification while illustrating the potential for improvement through marker‐assisted selection.
MS‐275, a Class I histone deacetylase inhibitor, protects the p53‐deficient mouse against ischemic injury
Authors: Murphy Sean P. , Lee Rona J. , McClean Megan E. , Pemberton Heather E. , Uo Takuma , Morrison Richard S. , Bastian Chinthasagar , Baltan Selva
Published: October 2013

The administration of pan histone deacetylase (HDAC) inhibitors reduces ischemic damage to the CNS, both in vitro and in animal models of stroke, via mechanisms which we are beginning to understand. The acetylation of p53 is regulated by Class I HDACs and, because p53 appears to play a role in ischemic pathology, the purpose of this study was to discover, using an in vitro white matter ischemia model and an in vivo cerebral ischemia model, if neuroprotection mediated by HDAC inhibition depended on p53 expression. Optic nerves were excised from wild‐type and p53‐deficient mice, and then subjected to oxygen–glucose deprivation in the presence and absence of a specific inhibitor of Class I HDACs (MS‐275, entinostat) while compound action potentials were recorded. Furthermore, transient focal ischemia was imposed on wild‐type and p53‐deficient mice, which were subsequently treated with MS‐275. Interestingly, and in both scenarios, the beneficial effects of MS‐275 were most pronounced when p53 was absent. These results suggest that modulation of p53 activity is not responsible for MS‐275‐mediated neuroprotection, and further illustrate how HDAC inhibitors variably influence p53 and associated apoptotic pathways.

image

Optic nerves from wild‐type and p53‐deficient mice, engineered to express cyan fluorescent protein (CFP) in neuronal mitochondria, were subjected to oxygen–glucose deprivation (OGD) in the presence and absence of a specific inhibitor of Class I histone deacetylases. The protective effect of MS‐275 was evidenced by mitochondrial preservation, and this was most pronounced in the absence of p53.
Comparisons of Patient Satisfaction Levels with Complete Dentures of Different Occlusions: A Randomized Clinical Trial
Authors: Shirani Mohhamadjavad , Mosharraf Ramin , Shirany Mohammadkazem
Published: October 2013

Purpose

There is a lack of evidence to recommend a particular type of posterior occlusal form for conventional complete dentures. The type of posterior occlusal scheme can affect complete denture stability, retention, and patient satisfaction. The objective of this study was to compare patient satisfaction to three types of complete denture occlusion using a randomized, crossover controlled trial.

Materials and Methods

Three sets of complete dentures were made for each of 15 patients (mean age = 58.87 ± 15.02 years). They received (1) fully bilateral balanced occlusion (BBO), (2) lingualized occlusion, and (3) buccalized occlusion (BO) denture sets in random order. After wearing each set for 6 weeks, patient satisfaction was assessed using a 19‐item version of the Oral Health Impact Profile for Edentulous Patients (OHIP‐EDENT). Each question was scored on a 1 to 5 scale for patients’ problems with dentures (for these ordinal variables, 1 = “never” and 5 = “very often”). These items were first analyzed by Friedman tests and then by Wilcoxon rank tests for 80% test power at the 0.05‐alpha level (d = 0.7).

Results

BO resulted in lower avoidance of particular foods and physical disability scores than fully BBO.

Conclusions

With the caution of small sample size, the results of this study provide evidence that use of BO can improve food avoidance and physical disability aspects of patient satisfaction with complete dentures.
School‐Based Health Promotion Intervention: Parent and School Staff Perspectives
Authors: Patino‐Fernandez Anna M. , Hernandez Jennifer , Villa Manuela , Delamater Alan
Published: October 2013

BACKGROUND

The prevalence of childhood obesity is high, particularly among minority youth. The objective of this article was to evaluate parent and school staff perspectives of childhood health and weight qualitatively to guide the development of a school‐based obesity prevention program for minority youth.

METHODS

Hispanic parents (N = 9) of first graders participated in 1 of 3 focus groups, consisting of 3 parents each. School staff (N = 7) participated in 1 focus group. All sessions were digitally recorded and transcribed verbatim. Using NVivo, 2 independent coders rated the transcriptions to identify themes and a third coder addressed commonalities and discrepancies in the coding schemes.

RESULTS

Parents and school staff have conflicting views over whose responsibility it is to provide nutritional education and participation in physical activity (PA). Parents felt the school should teach children about healthy nutrition, provide guidance in the cafeteria, and offer more structured PA in school. In contrast, school staff noted that parents have the primary responsibility of ensuring children get adequate nutrition and PA.

CONCLUSIONS

Despite contrasting views, parents and staff agreed with the need for comprehensive school‐based obesity prevention efforts emphasizing parent and teacher collaboration to promote healthy school and home environments.
Changes in melatonin levels in transgenic ‘Micro‐Tom’ tomato overexpressing ovine AANAT and ovine HIOMT genes
Authors: Wang Lin , Zhao Yu , Reiter Russel J. , He Changjiu , Liu Guoshi , Lei Qiong , Zuo Bixiao , Zheng Xiao Dong , Li Qingtian , Kong Jin
Published: October 2013

In animals, the melatonin biosynthesis pathway has been well defined after the isolation and identification of the four key genes that are involved in the conversion of tryptophan to melatonin. In plants, there are special alternative catalyzing steps, and plant genes share very low homology with the animal genes. It was of interest to examine the phenotype of transgenic Micro‐Tom tomato plants overexpressing the homologous sheep oAANAT and oHIOMT genes responsible for the last two steps of melatonin synthesis. The oAANAT transgenic plants have higher melatonin levels and lower indoleacetic acid (IAA) contents than control due to the competition for tryptophan, the same precursor for both melatonin and IAA. Therefore, the oAANAT lines lose the ‘apical dominance’ inferring that melatonin likely lacks auxin activity. The significantly higher melatonin content in oHIOMT lines than oAANAT lines provides new proof for the important role of ASMT in plant melatonin synthesis. In addition, the enhanced drought tolerance of oHIOMT lines will also be an important contribution for plant engineering.
Peripartal calcium homoeostasis of multiparous dairy cows fed rumen‐protected rice bran or a lowered dietary cation/anion balance diet before calving
Authors: Martín‐Tereso J. , ter Wijlen H. , van Laar H. , Verstegen M. W. A.
Published: October 2013

Milk fever is one of the most important metabolic diseases in dairy cattle. Reducing the dietary cation/anion balance (DCAD) with anionic salts is a common prevention strategy. However, many small European farms cannot use total mixed rations (TMR) in the close‐up period. Including anionic salts in compound feeds can result in feed refusals and moderate inclusions to preserve feed palatability results in insufficient DCAD reduction. Rumen‐protected rice bran induces the adaptation of Ca metabolism in dairy cows by a reduction of Ca intake and by a reduction of the availability of dietary Ca. In the presence of a negative control, rumen‐protected rice bran (2.8 kg/day) was compared with a lowered DCAD diet (from 269 to 4 meq/kg DM) in their effect to prevent milk fever. In a randomized block design, 45 multiparous Holstein cows joined the trial sequentially from 21 days before the expected calving date and were observed until the 8th week of lactation. Feed and nutrient intakes were recorded, and Ca, P, Mg in serum and urine, urine pH, serum NEFA and milk production in early lactation were compared. Feeding rumen‐protected rice bran before calving improved the recovery of calcaemia after calving and had a positive effect on DMI after calving. The moderately low DCAD diet did not positively influence serum Ca at calving. Calcaemia recovered even later than in control, and cows showed reduced DMI post‐calving and higher NEFA levels in the first 36 h after calving. This moderate reduction of DCAD did not provide an intermediate prevention level indicating that DCAD needs to be reduced to the recommended levels to prevent milk fever. Rumen‐protected rice bran may be a suitable feed to reduce hypocalcaemia post‐partum and can be included in pre‐calving compound feeds representing a palatable alternative to anionic salts.
Above the Roof, Beneath the Law: Perceived Justice behind Disruptive Tactics of Migrant Wage Claimants in China
Authors: He Xin , Wang Lungang , Su Yang
Published: October 2013

The way in which citizens in developing countries conceptualize legality is a critical but understudied question for legal consciousness and legal mobilization studies. Drawing on participatory observations and extensive interviews from western China, this article explores the subjective interpretations of migrant wage claimants on law and justice behind their disruptive actions. Their perception of justice differs starkly from what the law stipulates as target, evidence and proper procedures. Who shall be held responsible? What constitutes evidence? When shall they be paid? How much? Their perceptions also differ from the attitude “against the law” found among members from disadvantaged social groups in the United States. The Chinese case of legal perception is shaped by the moral precepts ingrained in the culture, and more importantly, by the lopsided relationship between migrant workers and the political and business elite. It thus points to the daunting barriers in channeling the ever-growing number of social conflicts into court.
Biodiversity in transitional waters: steeper ecotone, lower diversity
Authors: Reizopoulou Sofia , Simboura Nomiki , Barbone Enrico , Aleffi Floriana , Basset Alberto , Nicolaidou Artemis
Published: October 2013

Benthic communities were studied in four transitional water ecosystems in the Mediterranean, located in Albania (Narta), Greece (Logarou) and Italy (Grado‐Marano and Margherita di Savoia), with different degrees of salinity ranges, in order to investigate biodiversity trends across a scale of environmental stress. The intensity of natural stress in the transition zones, from the marine‐based to the land‐based influence, varied from gradual to sharp. The spatial variability in the physical environment had a stronger effect on species richness than did the temporal fluctuations. The sharper the spatial variations of salinity, the lower the number of species and the diversity level of the system. The differences in intensity of natural instability were also reflected by the presence of different sets of species, with the euryhaline species developing large populations and dominating the more enclosed systems, whereas the marine component of the fauna plays the most important role in increasing the level of benthic diversity.
Three Practical Assignments for the Introductory Risk Management and Insurance Student
Authors: Gatzlaff Kevin M.
Published: October 2013

I have developed, used, and refined an auto quote assignment, a life quote assignment, and a retirement analysis assignment that seem to communicate certain concepts well to the typical student enrolled in a risk management and insurance principles course. These assignments consist of worksheets requiring Internet research and a series of questions based on the answers discovered. Additionally, a short class discussion follows each of the three assignments to further ensure that students have achieved the primary learning objectives of each assignment. In their current form, these assignments are practical and require relatively minimal student and instructor time. Each could easily be expanded to accommodate students with advanced understanding and capability.
Recent Research Developments Affecting Nonlife Insurance—The CAS Risk Premium Project 2012 Update
Authors: Biener Christian , Eling Martin
Published: October 2013

This article reports the main results of the 2012 Risk Premium Project update, a yearly review of actuarial and finance literature on the theory and empirics of risk assessment for property–casualty insurance. Pricing and modeling insurance risks and methodological advancement in risk valuation were popular fields of research in 2012. Of special note is new work on behavioral pricing and liquidity. Additionally, underwriting cycles attracted some controversy, and emerging risks, such as systemic risk and potential interrelations between insurance and other financial markets, were also areas of intense discussion.
Standardization of skin cleansing in vivo: part I. Development of an Automated Cleansing Device (ACiD)
Authors: Sonsmann F. K. , Strunk M. , Gediga K. , John C. , Schliemann S. , Seyfarth F. , Elsner P. , Diepgen T. L. , Kutz G. , John S. M.
Published: October 2013

Background

To date, there are no legally binding requirements concerning product testing in cosmetics. This leads to various manufacturer‐specific test methods and absent transparent information on skin cleansing products. A standardized in vivo test procedure for assessment of cleansing efficacy and corresponding barrier impairment by the cleaning process is needed, especially in the occupational context where repeated hand washing procedures may be performed at short intervals.

Methods

For the standardization of the cleansing procedure, an Automated Cleansing Device (ACiD) was designed and evaluated. Different smooth washing surfaces of the equipment for ACiD (incl. goat hair, felt, felt covered with nitrile caps) were evaluated regarding their skin compatibility.

Results

ACiD allows an automated, fully standardized skin washing procedure. Felt covered with nitrile as washing surface of the rotating washing units leads to a homogenous cleansing result and does not cause detectable skin irritation, neither clinically nor as assessed by skin bioengineering methods (transepidermal water loss, chromametry).

Conclusions

Automated Cleansing Device may be useful for standardized evaluation of the cleansing effectiveness and parallel assessment of the corresponding irritancy potential of industrial skin cleansers. This will allow objectifying efficacy and safety of industrial skin cleansers, thus enabling market transparency and facilitating rational choice of products.
Rice DB: an Oryza Information Portal linking annotation, subcellular location, function, expression, regulation, and evolutionary information for rice and Arabidopsis
Authors: Narsai Reena , Devenish James , Castleden Ian , Narsai Kabir , Xu Lin , Shou Huixia , Whelan James
Published: October 2013

Omics research in Oryza sativa (rice) relies on the use of multiple databases to obtain different types of information to define gene function. We present Rice DB, an Oryza information portal that is a functional genomics database, linking gene loci to comprehensive annotations, expression data and the subcellular location of encoded proteins. Rice DB has been designed to integrate the direct comparison of rice with Arabidopsis (Arabidopsis thaliana), based on orthology or ‘expressology’, thus using and combining available information from two pre‐eminent plant models. To establish Rice DB, gene identifiers (more than 40 types) and annotations from a variety of sources were compiled, functional information based on large‐scale and individual studies was manually collated, hundreds of microarrays were analysed to generate expression annotations, and the occurrences of potential functional regulatory motifs in promoter regions were calculated. A range of computational subcellular localization predictions were also run for all putative proteins encoded in the rice genome, and experimentally confirmed protein localizations have been collated, curated and linked to functional studies in rice. A single search box allows anything from gene identifiers (for rice and/or Arabidopsis), motif sequences, subcellular location, to keyword searches to be entered, with the capability of Boolean searches (such as AND/OR). To demonstrate the utility of Rice DB, several examples are presented including a rice mitochondrial proteome, which draws on a variety of sources for subcellular location data within Rice DB. Comparisons of subcellular location, functional annotations, as well as transcript expression in parallel with Arabidopsis reveals examples of conservation between rice and Arabidopsis, using Rice DB (http://ricedb.plantenergy.uwa.edu.au).
Cartographies of remembrance and becoming in the Sierra de Perijá, Venezuela
Authors: Sletto Bjorn Ingmunn
Published: October 2013

This article examines the role of memory performance in participatory mapping in indigenous communities, in particular in terms of driving radical action for territorial rights. By examining the links between memory performance, processes of identity formation and the social constructions of landscape, the article suggests that greater critical consideration should be given to participatory mapping as process, as opposed to participatory maps as products. This is particularly important in the current push for land, resource and territorial rights among indigenous peoples in Venezuela and beyond. The article is based on a participatory mapping project conducted with indigenous residents of the Yukpa community of Toromo in the Sierra de Perijá, Venezuela, in the years 2007–2011. The mapping process inspired the speaking of memory, which in turn articulated with autochthonous debates regarding land rights and development strategies. By drawing on Ricoeur's conceptualisation of memory and narrative identity, the article presents and critically analyses memory performances of violence, exile and deceit, which reflect memory themes constitutive of a ‘duty to remember’ and ‘a duty to map’ so often expressed by Yukpa.
Exogenously applied muscle metabolites synergistically evoke sensations of muscle fatigue and pain in human subjects
Authors: Pollak Kelly A. , Swenson Jeffrey D. , Vanhaitsma Timothy A. , Hughen Ronald W. , Jo Daehyun , Light Kathleen C. , Schweinhardt Petra , Amann Markus , Light Alan R.
Published: October 2013

New Findings

What is the central question of this study?

Can physiological concentrations of metabolite combinations evoke sensations of fatigue and pain when injected into skeletal muscle? If so, what sensations are evoked?

What is the main finding and its importance?

Low concentrations of protons, lactate and ATP evoked sensations related to fatigue. Higher concentrations of these metabolites evoked pain. Single metabolites evoked no sensations. This suggests that the combination of an ASIC receptor and a purinergic P2X receptor is required for signalling fatigue and pain. The results also suggest that two types of sensory neurons encode metabolites; one detects low concentrations of metabolites and signals sensations of fatigue, whereas the other detects higher levels of metabolites and signals ache and hot.

The perception of fatigue is common in many disease states; however, the mechanisms of sensory muscle fatigue are not understood. In mice, rats and cats, muscle afferents signal metabolite production in skeletal muscle using a complex of ASIC, P2X and TRPV1 receptors. Endogenous muscle agonists for these receptors are combinations of protons, lactate and ATP. Here we applied physiological concentrations of these agonists to muscle interstitium in human subjects to determine whether this combination could activate sensations and, if so, to determine how the subjects described these sensations. Ten volunteers received infusions (0.2 ml over 30 s) containing protons, lactate and ATP under the fascia of a thumb muscle, abductor pollicis brevis. Infusion of individual metabolites at maximal amounts evoked no fatigue or pain. Metabolite combinations found in resting muscles (pH 7.4 + 300 nm ATP + 1 mm lactate) also evoked no sensation. The infusion of a metabolite combination found in muscle during moderate endurance exercise (pH 7.3 + 400 nm ATP + 5 mm lactate) produced significant fatigue sensations. Infusion of a metabolite combination associated with vigorous exercise (pH 7.2 + 500 nm ATP + 10 mm lactate) produced stronger sensations of fatigue and some ache. Higher levels of metabolites (as found with ischaemic exercise) caused more ache but no additional fatigue sensation. Thus, in a dose‐dependent manner, intramuscular infusion of combinations of protons, lactate and ATP leads to fatigue sensation and eventually pain, probably through activation of ASIC, P2X and TRPV1 receptors. This is the first demonstration in humans that metabolites normally produced by exercise act in combination to activate sensory neurons that signal sensations of fatigue and muscle pain.
Internal Transport Coefficient Measurements in Random Fiber Matrix Heat Exchangers
Authors: Geb David , Lerro Angelo , Sbutega Krsto , Catton Ivan
Published: October 2013

Experimental determination of transport coefficients, in particular internal heat transfer coefficients, in heterogeneous and hierarchical heat transfer devices such as compact regenerative heat exchangers has posed a persistent challenge for designers. The goal of this study is to (1) present a new general treatment of the experimental determination of such design data, to (2) provide simple correlations for high porosity random fiber matrices for broad design applications, and to (3) illustrate how such measurements close the formidable integro-differential volume averaging theory (VAT) equations governing transport phenomena in porous media. The combined experimental and computational method employed here for determining the internal heat transfer coefficient in the porous structure is based on the VAT model and combines with simple pressure drop measurements to yield the relevant design data for eight different high porosity random fiber samples. The design data are correlated based on a porous media length scale derived from the VAT model governing equations and the transport coefficient correlations obtained are valid for gas flows over a Reynolds number range between 5 and 70. Finally, the correlations are related to explicit, rigorously derived, lower-scale expressions arising from the VAT model. With the illustration of a new experimental tool, and the production of new simple design correlations for high porosity random fiber matrices for regenerative heat transfer applications, within the context of the hierarchical VAT model, future VAT-based simulation studies of such devices may be pursued. Moreover, the nonlocal modeling provided by VAT paves the way to meaningful optimization studies due to its singular ability to provide rigorous modeling and fast numerical solutions for transport phenomena in regenerative compact heat exchangers.
Analysis of the Hydraulic Resistance of a Water Wall Based on a Distributed Parameter Model in a Supercritical Once-Through Boiler
Authors: Luo Zixue , Deng Yanxiang , Zheng Shu , Zhou Huaichun
Published: October 2013

Accurate prediction of the hydraulic resistance is helpful for the safe operation of a water wall in a supercritical boiler. In this paper, the density distribution for the resistance calculation of a water wall at the supercritical pressure is numerically analyzed, and a distributed parameter model of the hydraulic resistance is developed in a down-fired 600 MWe supercritical boiler using a three-dimensional temperature distribution. The results show that the difference in the density along the radial direction is small and that the hydraulic resistance of the water wall tubes at the supercritical pressure is affected by the critical phenomenon of the working fluid and the allocation of heat flux of the boiler. The simulation cases and in situ operation data demonstrate the model. The model provides a new analysis method for the hydraulic resistance characteristics of a water wall in this thermodynamic system, and the derived model builds a foundation for developing flow monitoring and a thermal-hydraulic design.
Performance Analysis and Feedback Control of ATRIAS, A Three-Dimensional Bipedal Robot
Authors: Ramezani Alireza , Hurst Jonathan W. , Akbari Hamed Kaveh , Grizzle J. W.
Published: October 2013

This paper develops feedback controllers for walking in 3D, on level ground, with energy efficiency as the performance objective. Assume The Robot Is A Sphere (ATRIAS) 2.1 is a new robot that has been designed for the study of 3D bipedal locomotion, with the aim of combining energy efficiency, speed, and robustness with respect to natural terrain variations in a single platform. The robot is highly underactuated, having 6 actuators and, in single support, 13 degrees of freedom. Its sagittal plane dynamics are designed to embody the spring loaded inverted pendulum (SLIP), which has been shown to provide a dynamic model of the body center of mass during steady running gaits of a wide diversity of terrestrial animals. A detailed dynamic model is used to optimize walking gaits with respect to the cost of mechanical transport (CMT), a dimensionless measure of energetic efficiency, for walking speeds ranging from 0.5 (m/s) to 1.4 (m/s). A feedback controller is designed that stabilizes the 3D walking gaits, despite the high degree of underactuation of the robot. The 3D results are illustrated in simulation. In experiments on a planarized (2D) version of the robot, the controller yielded stable walking.
Adaptive Active Chatter Control in Milling Processes
Authors: Chen Zhiyong , Zhang Hai-Tao , Zhang Xiaoming , Ding Han
Published: October 2013

Chatter is an undesirable dynamic phenomenon in machining processes, which causes cutting disturbance, overcut, quick tool wear, etc., and thus seriously impairs workpiece quality. To mitigate chatter, traditional methods called passive control focus on optimizing working spindle speeds and depths of cut. But they have inherent disadvantages in gaining highly efficient machining. On the contrary, the research in this paper is along the line of active control. Specifically, an adaptive algorithm is developed based on Fourier series analysis to deal with the so-called regenerative cutting force which causes chatter. As a result, chatter is remarkably mitigated. The performance improvement is illustrated by numerical simulation in terms of both stability lobes diagram (SLD) and surface location error (SLE).
Observations of the Critical Heat Flux Process During Pool Boiling of FC-72
Authors: Jung J. , Kim S. J. , Kim J.
Published: October 2013

Experimental work was undertaken to investigate the process by which pool-boiling critical heat flux (CHF) occurs using an IR camera to measure the local temperature and heat transfer coefficients on a heated silicon surface. The wetted area fraction (WF), the contact line length density (CLD), the frequency between dryout events, the lifetime of the dry patches, the speed of the advancing and receding contact lines, the dry patch size distribution on the surface, and the heat transfer from the liquid-covered areas were measured throughout the boiling curve. Quantitative analysis of this data at high heat flux and transition through CHF revealed that the boiling curve can simply be obtained by weighting the heat flux from the liquid-covered areas by WF. CHF mechanisms proposed in the literature were evaluated against the observations.
Impact of Above-Grade Walls on Three-Dimensional Building Foundation Heat Transfer From Slab-On Grade Floors
Authors: Krarti Moncef
Published: October 2013

This paper presents a new three-dimensional analytical solution for transient ground-coupled heat transfer associated with slab-on-grade floor building foundations. The impact of above-grade walls on ground-coupled heat transfer is accounted for in the presented solution. The interzone temperature profile estimation (ITPE) technique is utilized to obtain the 3D solution suitable to determine soil temperature distributions and to estimate foundation heat loss/gain from slab-on-grade floors. The ITPE results are validated against results obtained from a closed-form solution in the case of steady-state conditions. It is found that that the above-grade walls can significantly affect the foundation heat losses especially for uninsulated slabs. Moreover, a simplified approach is proposed to obtain three-dimensional foundation heat losses from a two-dimensional solution.
Analysis of Advanced Supercritical Carbon Dioxide Power Cycles With a Bottoming Cycle for Concentrating Solar Power Applications
Authors: Besarati Saeb M. , Yogi Goswami D.
Published: October 2013

A number of studies have been performed to assess the potential of using supercritical carbon dioxide (S-CO2) in closed-loop Brayton cycles for power generation. Different configurations have been examined among which recompression and partial cooling configurations have been found very promising, especially for concentrating solar power (CSP) applications. It has been demonstrated that the S-CO2 Brayton cycle using these configurations is capable of achieving more than 50% efficiency at operating conditions that could be achieved in central receiver tower type CSP systems. Although this efficiency is high, it might be further improved by considering an appropriate bottoming cycle utilizing waste heat from the top S-CO2 Brayton cycle. The organic Rankine cycle (ORC) is one alternative proposed for this purpose; however, its performance is substantially affected by the selection of the working fluid. In this paper, a simple S-CO2 Brayton cycle, a recompression S-CO2 Brayton cycle, and a partial cooling S-CO2 Brayton cycle are first simulated and compared with the available data in the literature. Then, an ORC is added to each configuration for utilizing the waste heat. Different working fluids are examined for the bottoming cycles and the operating conditions are optimized. The combined cycle efficiencies and turbine expansion ratios are compared to find the appropriate working fluids for each configuration. It is also shown that combined recompression-ORC cycle achieves higher efficiency compared with other configurations.
Optimization of a High-Speed Deployment Slider–Crank Mechanism: A Design Charts Approach
Authors: Mariti Lorenzo , Mucino Victor H. , Pennestrí Ettore , Cavezza Andres , Gautam Mridul , Valentini Pier Paolo
Published: October 2013

Mechanical and aerospace applications often require that mechanisms deploy in a quick stable and reliable way. The objective of this study is to implement a general optimization procedure to perform a first stage conceptual design of HSD mechanisms, focusing on both kinematics and dynamics. In particular, the authors will focus on the development of design charts. In the very first part of the work, a parametric lumped-mass system will be modeled in order to reduce the number of parameters for the synthesis phase. A correlation will be established between geometry, inertia and initial position to guarantee the maximum value of acceleration during deployment of the deployable arm by means of the principle of virtual work. In the second part of this work, the influence of important factors such as friction and joint clearance on the overall dynamics of the system will be investigated. Finally, a coupled dynamic and structural analysis of the helical spring, that actuates the mechanism, will be carried out in order to achieve optimal performance. The developed charts will also take into account the space limitation requirement, that are often needed for both aerospace and mechanical applications. A final example will summarize all the points covered by this research effort. Results will be validated using the commercial software ABAQUS.
Numerically Stable Design Optimization With Price Competition
Authors: Morrow W. Ross , Mineroff Joshua , Whitefoot Kate S.
Published: October 2013

Researchers in decision-based design (DBD) have suggested that business objectives, e.g., profits, should replace engineering requirements or performance metrics as the objective for engineering design. This requires modeling market performance, including consumer preferences and competition between firms. Game-theoretic “design-then-pricing” models—i.e., product design anticipating future price competition–provide an important framework for integrating consumer preferences and competition when design decisions must be made before prices are decided by a firm or by its competitors. This article concerns computational optimization in a design-then-pricing model. We argue that some approaches may be fundamentally difficult for existing solvers and propose a method that exhibits both improved efficiency and reliability relative to existing methods. Numerical results for a vehicle design example validate our theoretical arguments and examine the impact of anticipating pricing competition on design decisions. We find that anticipating pricing competition, while potentially important for accurately forecasting profits, does not necessarily have a significant effect on optimal design decisions. Most existing examples suggest otherwise, anticipating competition in prices is important to choosing optimal designs. Our example differs in the importance of design constraints, that reduce the influence the market model has on optimal designs.
Enabling Flexibility in Engineering Systems: A Taxonomy of Procedures and a Design Framework
Authors: Cardin Michel-Alexandre
Published: October 2013

This paper presents a five-phase taxonomy of systematic procedures to enable flexibility in the design and management of engineering systems operating under uncertainty. The taxonomy integrates contributions from surveys, individual articles, and books from the literature on engineering design, manufacturing, product development, and real options analysis obtained from professional e-index search engines. Thirty design procedures were classified based on the kind of early conceptual activities they support: baseline design, uncertainty recognition, concept generation, design space exploration, and process management. Each procedure is evaluated based on ease of use to enable flexibility analysis, whether it can be used directly in collaborative design activities, and has a proven applicability record in industry and research. The organizing principles integrate the procedures into a cohesive and systematic design framework. Demonstration applications on engineering systems case studies show that it helps designers select relevant procedures in different phases of the design process, depending on the context, available analytical resources, and objectives. In turn, the case studies show that the design framework helps generate concepts with improved lifecycle performance compared to baseline concepts. The taxonomy provides guidance to organize ongoing research efforts, and highlights potential contribution areas in this field of engineering design research.
Research on Joint Power and Loads Control for Large Scale Directly Driven Wind Turbines
Authors: Dai JuChuan , Liu Deshun , Hu Yanping , Shen Xiangbing
Published: October 2013

Emphasis of this article is on the dynamic characteristics analysis of individual pitch control for MW scale directly driven wind turbines with permanent magnet synchronous generator (PMSG). The pitch control objectives were analyzed and the objective expressions were deduced, including power expression, loads expression, and vibration expressions of blade and tower. Then, both the collective pitch control aiming at power control and the individual pitch control strategy aiming at joint power and loads control were analyzed, too. The blade root bending moments and the actual capture power of wind rotor were employed to be the control variables. The power was calculated based on the conventional measured parameters of wind turbines. In order to reflect the difference between the pitch angle command value and the actual value, the pitch actuator dynamic model was used. The research results show that both the collective pitch control strategy and the proposed individual pitch control strategy can effectively control the power injected into grid; moreover, the individual pitch control can reduce fatigue loads; while in the process of individual pitch control, the actual variation of blade pitch angle is closely related to not only the inflow speed but also the blade azimuth angle; individual pitch control strategy can reduce the variation amplitude of flapwise moments, but has little influence on the edgewise moments.
Investigation of Shroud Geometry to Passively Improve Heat Transfer in a Solar Thermal Storage Tank
Authors: Zemler Matthew K. , Boetcher Sandra K. S.
Published: October 2013

A shroud and baffle configuration is used to passively increase heat transfer in a thermal store. The shroud and baffle are used to create a vena contracta near the surface of the heat exchanger, which will speed up the flow locally and thereby increasing heat transfer. The goal of this study is to investigate the geometry of the shroud in optimizing heat transfer by locally increasing the velocity near the surface of the heat exchanger. Two-dimensional transient simulations are conducted. The immersed heat exchanger is modeled as an isothermal cylinder, which is situated at the top of a solar thermal storage tank containing water (Pr = 3) with adiabatic walls. The shroud and baffle are modeled as adiabatic, and the geometry of the shroud and baffle are parametrically varied. Nusselt numbers and fractional energy discharge rates are obtained for a range of Rayleigh numbers, 105 ≤ RaD ≤ 107 in order to determine optimal shroud and baffle configurations. It was found that a baffle width of 75% of the width of the heat exchanger provided the best heat transfer performance.