bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of β‐hydroxy‐β‐methylbutyrate in masticatory muscles of rats
Authors: Daré Leticia R. , Dias Daniel V. , Rosa Junior Geraldo M. , Bueno Cleuber R. S. , Buchaim Rogerio L. , Rodrigues Antonio de C. , Andreo Jesus C.
Published: November 2014

The aim of this research was to examine the influence of β‐hydroxy‐β‐methylbutyrate (HMB) on changes in the profile of muscle fibers, whether these alterations were similar between the elevator and depressor muscles of the jaw, and whether the effects would be similar in male and female animals. Fifty‐eight rats aged 60 days (29 animals of each gender) were divided into four groups: the initial control group (ICG) was sacrificed at the beginning of the experiment; the placebo control group (PCG) received saline and was fed ad libitum; the experimental group (EG) received 0.3 g kg−1 of HMB daily for 4 weeks by gavage as well as the same amount of food consumed by the PCG in the previous day; and the experimental ad libitum group (EAG) received the same dose of the supplement along with food ad libitum. Samples included the digastric and masseter muscles for the histoenzymological analysis. Data were subjected to statistical analysis with a significance level of P < 0.05. Use of HMB caused a decrease in the percentage of fast twitch glycolytic (FG) fibers and an increase in fast twitch oxidative glycolytic (FOG) fibers in males in both experimental groups (EG and EAG). However, it produced no increase in the muscle fiber area, in either gender, in the masseter muscle. In the digastric muscle, the HMB did not change the frequency or the area of any muscle fiber types in either gender. Our data suggest that the use of HMB caused small changes in the enzymological profile of fibers of the mastication muscles; the changes were different in the elevator and depressor muscles of the jaw and the results were different depending on gender.
Serum paraoxonase 1 (PON1) activity in acute pancreatitis of dogs
Authors: Tvarijonaviciute A. , García‐Martínez J. D. , Caldin M. , Martínez‐Subiela S. , Tecles F. , Pastor J. , Ceron J. J.
Published: November 2014

OBJECTIVES

Serum paraoxonase 1 is considered a marker of inflammation and oxidative damage. The aims of this study were to evaluate changes in serum paraoxonase 1 activity in dogs with acute pancreatitis, to correlate serum paraoxonase 1 activity and other analytes known to be altered in dogs with pancreatitis and to assess the relationship between serum paraoxonase 1 activity and disease severity in dogs with acute pancreatitis.

MATERIALS AND METHODS

Retrospective analysis of dogs with acute pancreatitis and healthy dogs in which serum paraoxonase 1 activity was measured were compared.

RESULTS

Median serum paraoxonase 1 activity was significantly lower in dogs with pancreatitis (n = 19) compared to healthy ones (n = 19). Serum paraoxonase 1 activity was negatively correlated with serum lipase and amylase activities, and C‐reactive protein and haptoglobin concentrations and was positively correlated with total cholesterol and glucose concentration. Disease severity was negatively correlated with serum paraoxonase 1 activity and positively correlated with triglyceride and C‐reactive protein concentration.

CLINICAL SIGNIFICANCE

Serum paraoxonase 1 activity is lower in dogs with acute pancreatitis and together with triglyceride and C‐reactive protein concentrations is a potential marker of disease severity.
Latin American and Caribbean Confederation of Household Workers: Political (Dis)Articulations
Authors: Martínez Prado Natalia
Published: November 2014

The aim of this paper is to address the configuration of the dominant identity categories in a Latin American feminine network that has historically claimed a lack of public recognition: the Latin American and Caribbean Confederation of Household Workers. Working from the perspective of political discourse theory presented in the first section, we briefly analyze the discourses of emergence and development of the Confederation, focusing on women's struggles to be recognized as “household workers.” Special attention is given to their (dis)articulations, particularly with feminists and Catholic lay sectors, as discourses or meaning configurations that conditioned their development as a collective subject. From our perspective, these processes of (dis)articulation established specific meanings for household workers’ practices, instituting their limits in relation to other political projects available, including those held by feminists. The dominant meanings of identity categories have not only enabled specific ways to be identified “as a household worker” but also imprinted the limits and possibilities of their political practice.
Abya Yala's Indigenous and Aboriginal Women: International Agenda of Integration and Solidarity
Authors: Galeano Sánchez Lady Katherine , Werner Meike
Published: November 2014

Today, the claims of Abya Yala's indigenous and aboriginal women are positioned within Latin America's indigenous agenda. This article analyzes the processes of emergence, articulation, consolidation, and integration of Abya Yala's indigenous and aboriginal women into the Continental Indigenous Women's Summit Meeting of Abya Yala, which has been held twice in the Americas, in Puno, Peru, in 2009 and in La María Piendamó, Colombia, in 2013. Through these summits, the specific claims of indigenous women have reached the international indigenous agenda and feminist and women's movements, promoting their autonomy. The article also examines the actors that favored the process of emergence, how the first and second summit meetings were held, and debates and selection of the topics. It addresses the challenges of this autonomous space managed and constituted by indigenous and aboriginal women of the continent.
Transnational Feminist Networks Building Regions in Latin America
Authors: Cabezas Almudena
Published: November 2014

This article presents an approach in feminist geopolitics that seeks to expand the regionalism approach to transnational feminist action in Latin America. After a brief discussion on literature, it analyzes the discourses and practices of three Latin American feminist networks, the Network of Women Transforming the Economy, the Latin American Chapter of International Gender and Trade Network, and Marcosur Feminist Articulation. It considers the meanings each network gives to integration to understand how they negotiated and decided on a tense, ambivalent meaning. The analysis of the symbolic and material negotiations of the transnational feminist networks studied and their encounters and conflicts show their contribution to building regions, the progressive redefinition of Latin America, and the emergence and consolidation of South America as a privileged reference for action. The reflections are based on intensive fieldwork conducted with more than 40 feminist activists in different Latin American countries from 2003 to 2004 and from 2010 to 2102.
Contribution of genetics to ecological restoration
Authors: Mijangos Jose Luis , Pacioni Carlo , Spencer Peter B. S. , Craig Michael D.
Published: November 2014

Ecological restoration of degraded ecosystems has emerged as a critical tool in the fight to reverse and ameliorate the current loss of biodiversity and ecosystem services. Approaches derived from different genetic disciplines are extending the theoretical and applied frameworks on which ecological restoration is based. We performed a search of scientific articles and identified 160 articles that employed a genetic approach within a restoration context to shed light on the links between genetics and restoration. These articles were then classified on whether they examined association between genetics and fitness or the application of genetics in demographic studies, and on the way the studies informed restoration practice. Although genetic research in restoration is rapidly growing, we found that studies could make better use of the extensive toolbox developed by applied fields in genetics. Overall, 41% of reviewed studies used genetic information to evaluate or monitor restoration, and 59% provided genetic information to guide prerestoration decision‐making processes. Reviewed studies suggest that restoration practitioners often overlook the importance of including genetic aspects within their restoration goals. Even though there is a genetic basis influencing the provision of ecosystem services, few studies explored this relationship. We provide a view of research gaps, future directions and challenges in the genetics of restoration.
How Fat‐Tailed is US Output Growth?
Authors: Franke Reiner
Published: November 2014

Several studies have recently rejected the common hypothesis that aggregate output is normally distributed. The present paper reconsiders this issue for US output growth. To this end, it focusses on the shape parameter b of the exponential power distribution (EPD), the two polar values of which constitute the normal distribution and the Laplace distribution with its fatter tails, respectively. The paper first warns against premature conclusions that neglect a structural break in output volatility. On the basis of a battery of Monte Carlo experiments, it is then found out that the results strongly depend on which subperiod is considered, the Great Inflation (GI) or the Great Moderation (GM) period, and which data are referred to, the growth rates of GDP, firm sector output, and quarterly or monthly industrial production (IP). Here, only quarterly IP can be said to exhibit fat tails in GI as well as GM; other evidence is mixed.
Exaggerated smooth muscle contraction segments on esophageal high‐resolution manometry: prevalence and clinical relevance
Authors: Mello M. D. , Duraiswamy S. , Price L. H. , Li Y. , Patel A. , Gyawali C. P.
Published: November 2014

Background

Two smooth muscle contraction segments (S2, S3) on esophageal high‐resolution manometry (HRM) demonstrate varying contraction vigor in symptomatic patients. Significance of isolated exaggerated smooth muscle contraction remains unclear.

Methods

High‐resolution manometry studies were reviewed in 272 consecutive patients (56.4 ± 0.8 years, 62% F) and compared to 21 healthy controls (27.6 ± 0.6 years, 52% F), using HRM tools (distal contractile integral, DCI; distal latency, DL; integrated relaxation pressure, IRP), Chicago Classification (CC) and multiple rapid swallows (MRS). Segments were designated merged when the trough between S2 and S3 was ≥150 mmHg, and exaggerated S3 when peak S3 amplitude was ≥150 mmHg without merging with S2. Presenting symptoms and global symptom severity (on 100 mm visual analog scale) were recorded. Prevalence of merged and exaggerated segments was determined, and characteristics compared to symptomatic patients with normal HRM, and to healthy controls.

Key Results

Merged segments were identified in 5.6%, and exaggerated S3 in another 12.5%, but only 17–50% had a CC diagnosis; one healthy control had merged segments. DCI with wet swallows was similar in cohorts with merged and exaggerated segments (p = 0.7), significantly higher than symptomatic patients with normal HRM and healthy controls (p ≤ 0.003 for each comparison). Incomplete inhibition and prominent DCI augmentation on MRS (p ≤ 0.01), and presenting symptoms (chest pain and dysphagia, p = 0.04) characterized exaggerated segments, but not demographics or symptom burden.

Conclusions & Inferences

Merged esophageal smooth muscle segments and exaggerated S3 may represent hypermotility phenomena from abnormal inhibition and/or excitation, and are not uniformly identified by the CC algorithm.
Gender specific effects of neonatal limited nesting on viscerosomatic sensitivity and anxiety‐like behavior in adult rats
Authors: Prusator D. K. , Greenwood‐Van Meerveld B.
Published: November 2014

Background

Evidence exists to suggest that early life stress (ELS), such as neglect or abuse has profound effects on the developing brain. The current study tests the hypothesis that ELS in the form of neonatal limited nesting (LN) may serve as a predisposing factor for the development of altered nociceptive processing and comorbid increases in anxiety‐like behavior in adulthood.

Methods

Both male and female neonatal Sprague–Dawley rats were subjected to LN from postnatal day (PND) 2‐9, while a control group was exposed to standard cage bedding. In adulthood, visceral sensitivity was assessed by quantifying a visceromotor behavioral response to graded isobaric pressures of colorectal distension. Hindpaw withdrawal thresholds in response to von Frey filaments were used to measure somatic sensitivity. Anxiety‐like behavior was assessed in adult life using both the elevated plus maze and open field assay.

Key Results

Early life stress in the form of neonatal LN induced visceral and somatic hypersensitivity in adult male rats and augmented anxiety‐like behavior. However, in adult cycling females, neonatal LN did not alter nociceptive processing or lead to changes in the levels of anxiety‐like behavior.

Conclusions & Inferences

Our findings suggest that in male rats the LN model is a novel tool to investigate the long‐term consequences of adverse early life experience on adult health.
Difficulty and Degrees of Moral Praiseworthiness and Blameworthiness
Authors: Nelkin Dana Kay
Published: November 2014

In everyday life, we assume that there are degrees of blameworthiness and praiseworthiness. Yet the debate about the nature of moral responsibility often focuses on the “yes or no” question of whether indeterminism is required for moral responsibility, while questions about what accounts for more or less blameworthiness or praiseworthiness are underexplored. In this paper, I defend the idea that degrees of blameworthiness and praiseworthiness can depend in part on degrees of difficulty and degrees of sacrifice required for performing the action in question. Then I turn to the question of how existing accounts of the nature of moral responsibility might be seen to accommodate these facts. In each case of prominent compatibilist and incompatibilist accounts that I consider, I argue that supplementation with added dimensions is required in order to account for facts about degrees of blameworthiness and praiseworthiness. For example, I argue that the reasons‐responsiveness view of Fischer and Ravizza (1998) requires supplementation that takes us beyond even fine‐grained measures of degrees of reasons‐responsiveness in order to capture facts about degrees of difficulty (contrary to the recent attempt by Coates and Swenson (2013) to extend the reasons‐responsiveness view by appealing to such measures). I conclude by showing that once we recognize the need for these additional parameters, we will be in a position to explain away at least some of the appeal of incompatibilist accounts of moral responsibility.
Physical activity preferences of older home care clients
Authors: Burton Elissa , Lewin Gill , Boldy Duncan
Published: November 2014

Background

Physical activity contributes to an older person's health and well‐being by maintaining strength, balance and mobility, all of which are important for older people who wish to remain living in their home for as long as possible. It is therefore essential that community nurses and those working with home care clients promote being physically active. To do this effectively requires an understanding of the type of physical activity older home care clients prefer to engage in.

Aim

The aims of this study were to identify the physical activity preferences of older people who received a home care service and to determine whether being physically active is important to this population.

Methods

Twenty older home care clients were interviewed using a semi‐structured interview schedule. Data were analysed using a descriptive qualitative methodology.

Results

Walking, housework and gardening were identified as the activities of choice. The majority of interviewees suggested that it was important to be physically active.

Conclusion

Structured exercise programmes are not the activity of choice for older home care clients. Therefore, when community nurses and allied health workers promote physical activity to their clients, they should suggest activities such as walking, housework and gardening and also endorse the benefits of physical activity for well‐being and staying independent.

Implication for practice

Health and community nurses and organisations should routinely encourage home care clients to increase their activity levels, especially utilising those activities they most enjoy.
Home healthcare teams’ assessments of pain in care recipients living with dementia: a Swedish exploratory study
Authors: Karlsson Christina Elisabeth , Ernsth Bravell Marie , Ek Kristina , Bergh Ingrid
Published: November 2014

Background

Pain assessment in people living with dementia is a challenge due to the complexity of pain and dementia and the difficulties in self‐reporting. In home healthcare, nurses are frequently involved in pain assessment situations and there is a need to explore how home healthcare teams’ manage pain assessment in this setting.

Aim

The study aimed to explore home healthcare teams’ experiences of pain assessment among care recipients with dementia.

Design

An exploratory qualitative design was used.

Methods

Open‐ended individual interviews were conducted with thirteen registered nurses and ten nursing assistants, working in three different home healthcare teams in one municipality in western Sweden. Philosophical hermeneutics was utilised to interpret the home healthcare teams’ experiences.

Results

Four interpretations emerged: the need for trusting collaboration, the use of multiple assessment strategies, maintenance of staff continuity in care and assessment situations, and the need for extended time to assess pain.

Conclusions

The home healthcare teams recognise pain assessment in people with dementia as involving a complex interaction of sensory, cognitive, emotional and behavioural components in which efforts to acquire understanding of behavioural changes mainly guides their assessments. The solid team coherence between registered nurses and nursing assistants aided the assessment procedure. To assess pain, the teams used multiple methods that complemented one another. However, no systematic routines or appropriate evidence‐based pain tools were used.

Implications for Practice

The team members'concern for care recipients when assessing pain is evident and needs to be acknowledged by the organisation which is responsible for the quality of care. Future studies should focus on further exploration of nurses’ experiences with pain and dementia in home healthcare settings and address what nurses identify and how they deal with their findings. It is imperative to investigate how organisations and nurses can ensure best practices and how the implementation of evidence‐based routines for assessing pain may aid in pain assessment situations.
HPTLC screening of taro hybrids (Colocasia esculenta (L.) Schott) with high flavonoids and antioxidants contents
Authors: Lebot Vincent , Legendre Laurent
Published: November 2014

Taro (Colocasia esculenta) is the tropical root crop species featuring the greatest flavonoids diversity. Their quantification is important for breeding programmes focusing on biofortification. This study aims at developing an HPTLC protocol to compare the flavonoids fingerprints of more than 1800 hybrids belonging to 24 full‐sib families and to select genotypes with high levels of antioxidants. Twenty different chemical markers were identified based on bands Rf and colour. Flavonoids differ among individuals both quantitatively and qualitatively. Marker ‘A’ yielded the strongest antioxidant response to DPPH, equivalent to the one with quercetin pure standard. Overall, 377 high flavonoids content (HFC) hybrids were selected from 14 different families. The mean corm weight of HFC hybrids always appeared higher than the mean corm weight of the family they belong to. This method allows unambiguous selection of HFC hybrids. It also contributes to taro genetic improvement for nutritional value and access to new markets and to strengthen corm tolerance to pests and diseases. It could be applied to other tropical root crop species.
Ultraviolet Index and Location are Important Determinants of Vitamin D Status in People with Human Immunodeficiency Virus
Authors: Klassen Karen M. , Fairley Christopher K. , Kimlin Michael G. , Kelly Mark , Read Tim R.H. , Broom Jennifer , Russell Darren B. , Ebeling Peter R.
Published: November 2014

This study aimed to document the vitamin D status of HIV‐infected individuals across a wide latitude range in one country and to examine associated risk factors for low vitamin D. Using data from patients attending four HIV specialist clinics across a wide latitude range in Australia, we constructed logistic regression models to investigate risk factors associated with 25(OH)D < 75 nmol L−1. 1788 patients were included; 87% were male, 76% Caucasian and 72% on antiretroviral therapy. The proportion with 25(OH)D < 50 nmol L−1 was 27%, and <75 nmol L−1 was 54%. Living in Melbourne compared with Cairns (adjusted odds ratio (aOR) 3.30; 95% CI 2.18, 4.99, P < 0.001) and non‐Caucasian origin (aOR 2.82, 95% CI 2.12, 3.75, P < 0.001) was associated with an increased risk, while extreme UV index compared with low UV index was associated with a reduced risk (aOR 0.33; 95% CI 0.20, 0.55, P < 0.001) of 25(OH)D < 75 nmol L−1. In those with biochemistry available (n = 1117), antiretroviral therapy was associated with 25(OH)D < 75 nmol L−1; however, this association was modified by serum cholesterol status. Location and UV index were the strongest factors associated with 25(OH)D < 75 nmol L−1. Cholesterol, the product of an alternative steroid pathway with a common precursor steroid, modified the effect of antiretroviral therapy on serum 25(OH)D.
The Efficient Photocatalytic Degradation of Methyl Tert‐butyl Ether Under Pd/ZnO and Visible Light Irradiation
Authors: Seddigi Zaki S. , Ahmed Saleh A. , Bumajdad Ali , Danish Ekram Y. , Shawky Ahmed M. , Gondal Mohammed A. , Soylak Mustafa
Published: November 2014

Methyl tert‐butyl ether is a commonly used fuel oxygenate that is present in gasoline. It was introduced to eliminate the use of leaded gasoline and to improve the octane quality because it aids in the complete combustion of fuel by supplying oxygen during the combustion process. Over the past decade, the use of MTBE has increased tremendously worldwide. For obvious reasons relating to accidental spillage, MTBE started to appear as an environmental and human health threat because of its nonbiodegradable nature and carcinogenic potential, respectively. In this work, MTBE was degraded with the help of an advanced oxidation process through the use of zinc oxide as a photocatalyst in the presence of visible light. A mixture of 200 mg of zinc oxide in 350 mL of 50 ppm MTBE aqueous solution was irradiated with visible light for a given time. The complete degradation of MTBE was recorded, and approximately 99% photocatalytic degradation of 100 ppm MTBE solution was observed. Additionally, the photoactivity of 1% Pd‐doped ZnO was tested under similar conditions to understand the effect of Pd doping on ZnO. Our results obtained under visible light irradiation are very promising, and they could be further explored for the degradation of several nondegradable environmental pollutants.
Spatial analysis of the risk of major forest diseases in Monterey pine plantations
Authors: Iturritxa E. , Mesanza N. , Brenning A.
Published: November 2014

Diplodia pinea (causing diplodia blight), Fusarium circinatum (causing pitch canker), and Mycosphaerella spp. (causing needle blight) are examples of major fungal agents that damage Pinus spp. These diseases have a major negative impact on commercial plantation production, in addition to the risk of being introduced to native forest ecosystems. This study aimed to model the spatial risk of major forest diseases to Monterey pine plantations in northern Spain, to provide a basis for more focused management strategies. Generalized linear mixed‐effects models were used to identify empirical relationships between environmental variables and disease occurrence. Field surveys and laboratory tests confirmed that D. pinea caused shoot blight in 24% of sampled plantations. Fusarium circinatum and Mycosphaerella spp. were detected in 15 and 71% of analysed plantations, respectively. The results confirmed that disease risk was strongly related to summer precipitation, moderately related to solar radiation, followed by summer temperature and tree age. The predicted probability of disease incidence was >20, 98 and 85% for Mycosphaerella spp., F. circinatum and D. pinea, respectively. The resultant maps from this study may be used to identify high‐risk areas for increased monitoring and awareness of fungal diseases.
Guerrilla Statesmanship: Constitutionalizing an Ethic of Dissent
Authors: Newswander Chad B.
Published: November 2014

According to judicial precedents, administrators informed by their expertise can speak on issues of public concern under First Amendment protections. In one sense, they could dissent by working against their employers in an attempt to direct issues of public concern through an educational function. The power to act like a statesman in raising such issues allows administrators to lead from behind and in front, as long as certain judicial thresholds are met. However, the U.S. Supreme Court recently moved to tighten the scope of such activity. This article assesses how an ethic of dissent has been translated into a constitutional perspective that at first was moderately constrained and later became very restricted. While the move to limit an ethic of dissent provides necessary constraints, it also may have weakened administrators’ ability to perform necessary statesmanship acts rooted in guerrilla government to achieve the common good.
The Service Outsourcing Sector As Driver of Development: The Expectations of Ghana's Ict for Accelerated Development Programme
Authors: Beerepoot Niels , Keijser Charlotte
Published: November 2014

The service outsourcing sector is often regarded as a driver for economic growth of developing countries. The success story of India in acquiring foreign investments and building local firm capacity has led that many developing countries seek to develop an ICT‐driven development agenda. Ghana actively pursues such an agenda with its ICT4AD programme that aims at developing a knowledge economy. This paper concentrates on the Ghanaian efforts to attract foreign outsourcing firms and develop local firm capacity. While the ambitions are pointed towards servicing Western markets, it is rather the domestic and regional market that attracts foreign investors to invest in the Ghanaian outsourcing sector. Second, the paper identifies the symbolic significance of the sector. The service outsourcing sector is often used as a representation of a modernising Ghana and, despite its small size, provides a good illustration of the current optimism on Africa's development potential.
An Event‐driven Spatiotemporal Data Model (E‐ST) Supporting Dynamic Expression and Simulation of Geographic Processes
Authors: Li Xiaolong , Yang Jiansi , Guan Xuefeng , Wu Huayi
Published: November 2014

The wide use of various sensors makes real‐time data acquisition possible. A new spatiotemporal data model, the Event‐driven Spatiotemporal Data Model (E‐ST), is proposed to dynamically express and simulate the spatiotemporal processes of geographic phenomena. In E‐ST, a sensor object is introduced into the model as a flexible real‐time data source. An event type that is generating and driving conditions is registered into a geographic object, so an event can not only express spatiotemporal change in a geographic object, but also drive spatiotemporal change in some geographic objects. As a dynamic GIS data model, the E‐ST has five characteristics – Temporality and Spatiality, Real‐time, Extendability, Causality, and Realizability. Described and realized in UML, a test‐case deployment demonstrating the impact of urban waterlogging on traffic confirms that a spatiotemporal change process in a geographic phenomena is expressed and simulated by this model. Summarizing this work, four directions for future research are outlined.
Mechanisms of carotid body chemoreflex dysfunction during heart failure
Authors: Schultz Harold D. , Marcus Noah J. , Del Rio Rodrigo
Published: November 2014

New Findings

What is the topic of this review?

Carotid body chemoreceptor activity is tonically elevated in heart failure and contributes to morbidity due to the reflex activation of sympathetic nerve activity and destabilization of breathing. The potential causes for the enhanced chemoreceptor activation in heart failure are discussed.

What advances does it highlight?

The role of a chronic reduction in blood flow to the carotid body due to cardiac failure and its impact on signalling pathways in the carotid body is discussed.

Recent advances have attracted interest in the potential for carotid body (CB) ablation or desensitization as an effective strategy for clinical treatment and management of cardiorespiratory diseases, including hypertension, heart failure, diabetes mellitus, metabolic syndrome and renal failure. These disease states have in common sympathetic overactivity, which plays an important role in the development and progression of the disease and is often associated with breathing dysregulation, which in turn is likely to mediate or aggravate the autonomic imbalance. Evidence from both chronic heart failure (CHF) patients and animal models indicates that the CB chemoreflex is enhanced in CHF and contributes to the tonic elevation in sympathetic activity and the development of periodic breathing associated with the disease. Although this maladaptive change is likely to derive from altered function at all levels of the reflex arc, a tonic increase in afferent activity from CB glomus cells is likely to be a main driving force. This report focuses on our understanding of mechanisms that alter CB function in CHF and their potential translational impact on treatment of CHF.
Force steadiness during a co‐contraction task can be improved with practice, but only by young adults and not by middle‐aged or old adults
Authors: Holmes Matthew R. , Gould Jeffrey R. , Peña‐González Ilana , Enoka Roger M.
Published: November 2014

New Findings

What is the central question of this study?

Does the capacity to modulate afferent input to spinal motor neurons during steady submaximal contractions change with advancing age?

What is the main finding and its importance?

After practising a co‐contraction task involving lower leg muscles, young subjects improved force steadiness by reducing the amount of Ia presynaptic inhibition as indexed by D1 inhibition. Middle‐aged and old adults both found the task challenging, and force steadiness even worsened for old adults after practising the co‐contraction task. Despite similar muscle strength for young and middle‐aged adults, the capacity to modulate a spinal reflex pathway was reduced in middle‐aged adults.

This study compared the changes in steadiness and the modulation of presynaptic inhibition of soleus Ia afferents in young, middle‐aged and old adults before and after a single session of practising a task that involved concurrent contraction of dorsiflexor and plantarflexor muscles. The hypothesis was that young subjects would be able to improve steadiness with practice by modulating Ia afferent feedback as indicated by changes in a measure of presynaptic inhibition (D1 inhibition), but that middle‐aged and older subjects would exhibit a lesser ability to augment steadiness. There were no differences in steadiness between groups during an initial co‐contraction trial (P = 0.713). Maximal voluntary contraction force for the plantarflexors was not significantly different between young and middle‐aged subjects (P > 0.05), but it was significantly less in old subjects (P < 0.05). The main finding of the study was that young adults were able to improve steadiness by ∼19% (P < 0.001) during a co‐contraction task after 50 min of practice, whereas there was no change for the middle‐aged adults, and old adults became less steady by ∼15% (P < 0.05). The improvement in steadiness by young adults was accompanied by a significant reduction in the amount of Ia presynaptic inhibition as indexed by D1 inhibition (P < 0.01). Conversely, neither of the other two groups exhibited any change in D1 inhibition after practising the co‐contraction task. In contrast to young subjects, middle‐aged and old adults found the co‐contraction task challenging and were not able to improve steadiness after practising the low‐force isometric contraction.
A Review and Parametric Investigation Into Nanofluid Viscosity Models
Authors: Nwosu Paul N. , Meyer Josua , Sharifpur Mohsen
Published: November 2014

The degree of variability between theoretical and empirical nanofluid viscosity model predictions and relevant experimental data is examined in this work. Results confirm a high degree of variability in the compared data; with some observed inconsistencies in the model formulations and the predicted data, consequently, a range of constitutive factors need to be incorporated into the models in order to accurately predict the rheological behavior of nanofluids in different use conditions. Notably, conducting broad theoretical studies and empirical investigations into the rheological behavior of nanofluids incorporating the fundamental parametric variables can plausibly lead to near-generalized models.
Study on the Effect of Inlet Fluctuation on Cavitation in a Cone Flow Channel
Authors: Hai Liu , Shuping Cao , Xiaohui Luo
Published: November 2014

A mathematical method was conducted to investigate the mechanism of formation of cavitation cloud, while the inlet stream contains a fluctuating flow. Based on the Rayleigh–Plesset equation and the static pressure distribution in a cone flow channel, parameters related to cavitation cloud are estimated, and the collapse pressure of the cavitation cloud is obtained by solving the equation of Mørch’s model. Moreover, the effect of the amplitude and frequency of inlet fluctuation on cavitation is studied. Results revealed that the smaller the amplitude, the smaller the cloud and the lower the collapse pressure. And frequency of fluctuating stream was found to have a relative great effect on frequency of peak pressure but not so significant on peak collapse pressure and size of cloud. It is concluded that limiting the inlet fluctuation reduces the erosion and noise generated by cavitation collapse.
Safety Analysis of a Solid Oxide Fuel Cell/Gas Turbine Hybrid System Fueled With Gasified Biomass
Authors: Lv Xiaojing , Lu Chaohao , Zhu Xinjian , Weng Yiwu
Published: November 2014

The effect of biomass gas on the safety performance of a solid oxide fuel cell (SOFC)/micro gas turbine (GT) hybrid system was studied with consideration of the fuel cell working temperature, fuel cell temperature gradient requirement, compressor surge zone, and turbine inlet temperature (TIT). The safety performance of the hybrid system on the design condition and off-design condition was also analyzed. Results show that the hybrid system is good adaptability to low concentrations of biomass gas. The electrical efficiency could reach 50% with different biomass gases and is higher than the other combined power systems that used biomass gas. The wood chip gas (WCG) would make the fuel cell or GT easier overheat than the other three gases. The cotton wood gas (CWG) and corn stalk gas (CSG) are easy to cause the TIT too low or the compressor surge. In the safety zone, considering the hybrid system load adjustment range, the effecting order (from large to small, following is same) is WCG, grape seed gas (GSG), CSG, and CWG. Considering the hybrid system electric efficiency, the effecting order is WCG, GSG, CWG, and CSG.
Transient Couple Stress Fluid Past a Vertical Cylinder With Bejan’s Heat and Mass Flow Visualization for Steady-State
Authors: Rani H. P. , Janardhan Reddy G. , Nyung Kim Chang , Rameshwar Y.
Published: November 2014

In the present study, the transient, free convective, boundary layer flow of a couple stress fluid flowing over a vertical cylinder is investigated, and the heat and mass functions for the final steady-state of the present flow are developed. The solution of the time dependent nonlinear and coupled governing equations is obtained with the aid of an unconditionally stable Crank–Nicolson type of numerical scheme. Numerical results for the time histories of the skin-friction coefficient, Nusselt number, and Sherwood number as well as the steady-state velocity, temperature, and concentration are presented graphically and discussed. Also, it is observed that time required for the flow variables to reach the steady-state increases with the increasing values of Schmidt and Prandtl numbers, while the opposite trend is observed with respect to the buoyancy ratio parameter. To analyze the flow variables in the steady-state, the heatlines and masslines are used in addition to streamlines, isotherms, and isoconcentration lines. When the heat and mass functions are properly made dimensionless, its dimensionless values are related to the local and overall Nusselt and Sherwood numbers. Boundary layer flow visualization indicates that the heatlines and masslines are dense in the vicinity of the hot wall, especially near the leading edge.
Development of Prediction Technology of Two-Phase Flow Dynamics Under Earthquake Acceleration: (11) Bubble Motion Under the Flow Vibration
Authors: Yokoyama Ryotaro , Takano Jun-ichi , Monji Hideaki , Kaneko Akiko , Abe Yutaka , Yoshida Hiroyuki , Takase Kazuyuki
Published: November 2014

Earthquake is one of the most serious phenomena for safety of a nuclear power plant. Therefore, nuclear reactors were contracted considering structural safety for a big earthquake. In a nuclear reactor, the gas-liquid two-phase flow is the one of primary factor of the property and bubbly or plug flow behavior is important issue to evaluate of safety. However, the influence of an earthquake vibration on the gas-liquid two-phase flow inside the nuclear power plant is not understood enough. For example, the bubbly flow behavior under the flow rate fluctuation caused by the earthquake acceleration is not clear. It is necessary to clear the two-phase flow behavior under the earthquake conditions. To develop the prediction technology of two-phase flow dynamics under the earthquake acceleration, the detailed two-phase flow simulation code with an advanced interface tracking method, TPFIT was expanded to the two-phase flow simulation under earthquake accelerating conditions. In the present study, the objective is to clarify the behavior of the gas-liquid two-phase flow under the earthquake conditions. Especially, the bubble behavior in the two-phase flow, a diameter, shape and velocity of bubbles which are expected to be influenced by the oscillation of the earthquake is investigated. In this experiment, the flow was bubbly flow and/or plug flow in a horizontal circular pipe. The working fluids were water and nitrogen gas. The nitrogen gas from gas cylinder was injected into the water through a nozzle and bubbly flow was generated at a mixer. The water was driven by a pump and the flow rate fluctuation was given by a reciprocating piston attached to the main flow loop. Main frequency of earthquakes is generally between 0.5Hz and 10Hz. Thus the frequency of the flow rate fluctuation in the experiment also was taken between 0.5Hz and 10Hz. The behavior of horizontal gas-liquid two-phase flow under the flow rate fluctuation was investigated by image processing using a high-speed video camera and PIV at test section. The pressure sensors were installed at the inlet of the mixer and the outlet of the test section. As the result, the bubble behavior mechanism under the flow rate fluctuation was obtained. In addition, the acceleration of a bubble and the pressure gradient in the pipe was synchronized under all frequency conditions. The prediction results by TPFIT were compared with the experimental results. They show good agreement on the flow field around a bubble and the bubble behavior.
Progress of the HTR-10 Measured Data Utilization
Authors: Chen Fubing , Dong Yujie , Zheng Yanhua , Shi Lei , Li Fu , Zhang Zuoyi
Published: November 2014

The 10 MW High Temperature Gas-cooled Reactor-Test Module (HTR-10), which was designed, constructed and operated by the Institute of Nuclear and New Energy Technology (INET) of Tsinghua University, is the first High Temperature Gas-cooled Reactor (HTGR) in China. Stepping into the commissioning phase in April, 2000, the HTR-10 attained the first criticality in December, 2000 and achieved its full power operation in January, 2003. Up to now, the HTR-10 has been successfully operated for more than ten years with different power levels. During the relatively long period of commissioning and operation, various kinds of tests were carried out on this reactor. Within the scope of this paper, the commissioning stage, the operation history and the test implementation of the HTR-10 are briefly summarized.

At this stage, the HTR-10 is the only pebble bed HTGR under operation in the world, so the measured data from this reactor are extremely valuable for verifying the inherent safety features incorporated in small modular HTGRs as well as for testing the computer programs employed in the HTGR design process. With the purpose of ensuring the code credibility, validation work using the HTR-10 operation and test data has been performed for several years in INET. What is more, these data were partly shared with different countries through some collaborative research projects related to code development and assessment. In this paper, progress of the HTR-10 measured data utilization is reviewed. Meanwhile, existing problems observed from the code-to-test as well as code-to-code comparisons are pointed out. In addition, possible reasons of such problems are discussed in detail.
Feasibility of Enhanced Estimation of PWR Primary Parameters: Twin Experiments for Assessing Data Assimilation Benefits (0D-Model With a Monte-Carlo Approach on Pseudo-Real Data)
Authors: Mercier Thibaud , Favennec Jean-Melaine , Girard Alexandre
Published: November 2014

A PWR reactor coolant system is a highly complex physical process: heterogeneous power, flow and temperature distributions are difficult to be accurately measured, because instrumentations are limited in number, thus leading to the relevant safety and protection margins. This situation is in many ways similar to climate and weather models: a complex process that is not possible to sample and measure as finely as wanted. Meteorology and climate sciences have adapted and improved the Data Assimilation techniques in order to improve the accuracy of description and prediction in their fields.

EDF R&D is seeking to assess the potential benefits of applying Data Assimilation to a PWR’s RCS (Reactor Coolant System) measurements: is it possible to improve the estimates for parameters of a reactor’s operating set-point, i.e. improving accuracy and reducing uncertainties of measured RCS parameters?

In this paper we study the feasibility of enhanced estimation of PWR primary parameters, by using twin experiments for assessing Data Assimilation benefits. We simulated test samples with a 0D-Model, and used these samples in a Monte-Carlo approach to get background terms for Data Assimilation.

This successful preliminary study will lead to further assessments with real plant data.
Neutronics Studies on a Generic Pressure-Channel Reactor With Nuclear Steam Superheat
Authors: Baldock Matthew , Peiman Wargha , Vincze Andrei , Abdullah Rand , Sidawi Khalil , Pioro Igor
Published: November 2014

In order to increase the thermal efficiency of steam-cycle power plants it is necessary to achieve steam temperatures as high as possible. Current limiting factor for Nuclear Power Plants (NPPs) in achieving higher operating temperatures and, therefore, thermal efficiencies is pressures at which they can operate. From basic thermodynamics it is known that to increase further an outlet temperature in water-cooled reactors a pressure must also be increased. Current level of pressures in Pressurized Water Reactors (PWRs) is about 15–16 MPa. Therefore, next stage should be supercritical pressures, at least 23.5–25 MPa. However, such supercritical-water reactors with pressure vessels of 45–50 cm thickness don’t exist yet.

One way around larger pressure vessels as well as the limit of temperature of the coolant on the saturation pressure is to employ a Pressure Channel (PCh) design with Superheated Steam channels (SHS). PCh reactors allow for different coolants and bundle configurations in one reactor core, in this case, steam would be a secondary coolant. In the 1960s and 1970s the USA and Soviet Union tested reactors using pressure channels to super-heat steam in-core to achieve outlet temperatures greater than what is currently possible with convention reactors.

Nuclear materials are carefully chosen based on their neutron interaction properties in addition to their strength and resistance to corrosion. Introducing steam channels will not only change the neutronics behavior of the coolant, but require different fuel cladding and pressure-channel materials, specifically, stainless steels or Inconels, to withstand high-temperature steam. This paper will investigate the affect that steam, SS-304 and Inconel will have on neutron economy when introduced into a reactor design as well as required changes to fuel enrichment. It will also be necessary to investigate the effects of these material changes on power distribution inside a reactor. Pressure-channel design requires methods of fine control to maintain a balanced core-power distribution, the introduction of non-uniform coolant and reactor materials will further complicate maintaining uniform reactor power. The degree to which SHS channels will affect the power distribution is investigated in this paper.