bluuebunny/crossref_metadata_2025 huggingface dataset:
Exceptionally high fertility observed in three F1 hybrids between Lolium multiflorum Lam. and L. temulentum L.
Authors: Kiyoshi Takako , Arakawa Akira , Uchiyama Kazuhiro , Fujimori Masahiro , Mizuno Kazuhiko , Cai Hongwei
Published: May 2012

The pollen fertility and seed set of three F1 hybrid plants derived from a cross between a darnel ryegrass (Lolium temulentum L.) line (Ba3081) and a genotype of Italian ryegrass (L. multiflorum Lam.) were evaluated in field and greenhouse experiments under different temperatures. In the field where the daily mean temperature for 3 weeks prior to pollen dispersal was 16.5°C, the mean pollen fertility of the F1 plants was 42.8%, which was lower than the value observed in the parental species (96.0–98.1%). In two greenhouses with a daily mean temperature of 20.4 and 15.8°C, the mean pollen fertility of the F1 plants was 53.1% and 44.0%, respectively, which were higher than the values reported previously for the hybrids between L. temulentum × L. multiflorum (maximum of about 20%). The seed set of the F1 plants was 24% under open‐pollinated conditions in the field compared with 4.2–8.8% under self‐pollinated conditions in the two greenhouses. These results indicated that the F1 plants were self‐fertile and able to set F2 seed, with a significant reduction in pollen fertility occurring with a decrease in the daily mean temperature (2.15% decrease in fertility per unit decrease in temperature). The germination rate of the F2 seeds was approximately 57%, indicating the possibility of producing an F2 population for future genetic analysis. This is the first report of F1 plants from L. temulentum × L. multiflorum with fertile pollen and with the ability to produce progeny by self‐pollination. These findings suggest a possibility of developing recombinant inbred lines between L. temulentum and L. multiflorum.
Assessing Consumers’ Willingness to Pay for Different Units of Organic Milk: Evidence from Multiunit Auctions
Authors: Akaichi Faical , Nayga, Jr Rodolfo M. , Gil José M.
Published: May 2012

Experimental auctions are normally conducted using single‐unit auctions. In this paper, we use the multiunit Vickrey auction to assess the determinants of consumers’ willingness to pay (WTP) for organic milk in a multiunit shopping scenario. We also analyze the effect of positive and negative information about organic farming on WTP. Our results suggest that consumers are willing to pay a premium for organic milk but that this WTP decreases with the number of units purchased. Results also suggest that health issues, high price of organic foods, taste, and lack of information on organic foods are factors that influence WTP for organic milk. The type of information provided also plays a relevant role. Specifically, we found that subjects’ WTP responds positively to positive information about organic farming and responds negatively to negative information. The provision of both positive and negative information does not affect WTP.

Les enchères expérimentales sont en règle générale effectuées sous un cadre d’enchères de Vickrey à une seule unité. Dans le présent article, nous avons utilisé l’enchère de Vickrey à unités multiples pour évaluer les déterminants du consentement à payer (CAP) des consommateurs pour du lait biologique dans un contexte d’achats multiples. Nous avons également examiné les répercussions que l’information positive et négative à l’égard de l’agriculture biologique a sur le CAP. Nos résultats autorisent à penser que les consommateurs sont prêts à payer un prix plus élevé pour obtenir du lait biologique, mais que ce CAP diminue avec le nombre d’unités achetées. Nos résultats autorisent aussi à penser que les aspects liés à la santé, le prix élevé des aliments biologiques, le goût et le manque d’information sur ces aliments sont des facteurs qui influencent le CAP pour du lait biologique. Le type d’information joue également un rôle important. Nous avons observé que le CAP réagit favorablement à de l’information positive sur l’agriculture biologique et défavorablement à de l’information négative. La diffusion simultanée d’information positive et négative n’influence pas le CAP.
RAMSES-CH: a new chemodynamical code for cosmological simulations
Authors: Few C. G. , Courty S. , Gibson B. K. , Kawata D. , Calura F. , Teyssier R.
Published: May 2012

We present a new chemodynamical code –ramses-ch– for use in simulating the self-consistent evolution of chemical and hydrodynamical properties of galaxies within a fully cosmological framework. We build upon the adaptive mesh refinement code ramses, which includes a treatment of self-gravity, hydrodynamics, star formation, radiative cooling and supernova feedback, to trace the dominant isotopes of C, N, O, Ne, Mg, Si and Fe. We include the contribution of Type Ia and Type II supernovae, in addition to low- and intermediate-mass asymptotic giant branch stars, relaxing the instantaneous recycling approximation. The new chemical evolution modules are highly flexible and portable, lending themselves to ready exploration of variations in the underpinning stellar and nuclear physics. We apply ramses-ch to the cosmological simulation of a typical L★ galaxy, demonstrating the successful recovery of the basic empirical constraints regarding [α/Fe]–[Fe/H] and Type Ia/II supernova rates.
Detection of gravity modes in the massive binary V380 Cyg from Kepler space-based photometry and high-resolution spectroscopy
Authors: Tkachenko A. , Aerts C. , Pavlovski K. , Southworth J. , Degroote P. , Debosscher J. , Still M. , Bryson S. , Molenberghs G. , Bloemen S. , de Vries B. L. , Hrudkova M. , Lombaert R. , Neyskens P. , Pápics P. I. , Raskin G. , Van Winckel H. , Morris R. L. , Sanderfer D. T. , Seader S. E.
Published: May 2012

We report the discovery of low-amplitude gravity-mode oscillations in the massive binary star V380 Cyg, from 180 d of Kepler custom-aperture space photometry and 5 months of high-resolution high signal-to-noise ratio spectroscopy. The new data are of unprecedented quality and allowed the improvement of the orbital and fundamental parameters for this binary. The orbital solution was subtracted from the photometric data and led to the detection of periodic intrinsic variability with frequencies, of which some are multiples of the orbital frequency and others are not. Spectral disentangling allowed the detection of line-profile variability in the primary. With our discovery of intrinsic variability interpreted as gravity-mode oscillations, V380 Cyg becomes an important laboratory for future seismic tuning of the near-core physics in massive B-type stars.
Is legal knowledge cumulative?
Authors: Samuel Geoffrey
Published: May 2012

A relatively recent collective work published in France examines the extent to which social science knowledge is cumulative. However this work includes no chapter on law. The purpose of this paper is to imagine what a chapter on law might look like had one been invited by the editor. Is legal knowledge cumulative? This present paper is sceptical, although much depends on where one erects the boundaries between law and other social science disciplines. Yet, despite the scepticism, a reflection on cumulativeness and legal knowledge is not without interest. Indeed quite the opposite: for it generates a range of interesting sub-questions such as whether or not there have been paradigm changes in the discipline of law amounting to scientific revolutions.
Criminology, class and cricket: Raffles and real life
Authors: Ireland Richard W.
Published: May 2012

E W Hornung's character Raffles, first introduced to the public in 1898, not only aroused considerable interest at that time but created an enduring image of the suave, gentlemanly burglar far removed from the stereotype of the rough, professional thief more usually associated with the crime. This paper investigates both the creation of the character and the creation of the stereotype in the nineteenth century in an attempt to discover not only the secrets of the appeal of the Raffles, but also some of the characteristics of early criminological discourse, some of which may cast their shadows to the present day. It also highlights tensions between conceptions of ‘amateur’ and ‘professional’ status both in relation to the protagonist's lawful pastime, cricket, and his unlawful career of burglary.
Role of the laboratory in monitoring patients receiving dual antiplatelet therapy
Authors: VIDALI M. , ROLLA R. , PARRELLA M. , CASSANI C. , MANZINI M. , PORTALUPI M. R. , SERINO R. , PRANDO M. D. , BELLOMO G. , PERGOLINI P.
Published: May 2012

Introduction:  The increasing demand for therapeutic monitoring in patients receiving antiplatelet therapy has been paralleled by the development of instruments and tests whose clinical usefulness is still under debate. We devised a laboratory approach to detect patients with antiplatelet resistance at risk to develop thrombotic events.

Methods:  One hundred and eighty patients, under aspirin and clopidogrel after angioplasty and stent implantation, were studied by PFA100® with collagen/epinephrine (CoEPI, cutoff 165s) cartridge and by Multiplate® using arachidonic acid (ASPItest, pos < 862AUC), ADP (ADPtest, pos < 417AUC), and collagen (COLtest, pos < 607AUC).

Results:  Only 67 of 173 patients with ASPI < 862 displayed a prolonged CoEPI and up to 65 patients had normal CoEPI despite ASPI < 300. Patients with ASPI < 300 had significantly lower COL than patients with ASPI > 300. One hundred and thirty‐eight patients displaying ADP < 417 had significantly lower COL than those with ADP > 417. Association between COL and ADP remained after ASPI stratification: in patients with suboptimal (ASPI 300–892) or maximal (ASPI < 300) response to aspirin, having ADP < 417 (clopidogrel responsive) increased COL positivity, respectively, from 9.5 to 58.8% and from 47.6 to 82.7%.

Conclusion:  A combination of specific tests may be useful in identifying higher‐risk patients with poor compliance or drug resistance who potentially may benefit from therapy change.
Seawater Intrusion and Sustainable Yield of Basal Aquifers1
Authors: Liu Clark C.K. , Dai John J.
Published: May 2012

Liu, Clark C.K. and John J. Dai, 2012. Seawater Intrusion and Sustainable Yield of Basal Aquifers. Journal of the American Water Resources Association (JAWRA) 48(5): 861‐870. DOI: 10.1111/j.1752‐1688.2012.00659.x

Abstract:  Basal aquifers, in which freshwater floats on top of saltwater, are the major freshwater supply for the Hawaiian Islands, as well as many other coastal regions around the world. Under unexploited or natural conditions, freshwater and the underlying seawater are separated by a relatively sharp interface located below mean sea level at a depth of about 40 times the hydraulic head. With forced draft, the hydraulic head of a basal aquifer would decline and the sharp interface would move up. It is a serious problem of seawater intrusion as huge amounts of freshwater storage is replaced by saltwater. Also, with forced draft, the sharp interface is replaced by a transition zone in which the salinity increases downward from freshwater to saltwater. As pumping continues, the transition zone expands. The desirable source‐water salinity in Hawaii is about 2% of the seawater salinity. Therefore, the transition zone expansion is another serious problem of seawater intrusion. In this study, a robust analytical groundwater flow and salinity transport model (RAM2) was developed. RAM2 has a simple mathematical structure and its model parameters can be determined satisfactorily with the available field monitoring data. The usefulness of RAM2 as a viable management tool for coastal ground water management is demonstrated by applying it to determine the sustainable yield of the Pearl Harbor aquifer, a principal water supply source in Hawaii.
The Uncoupling Protein 2 ‐866G > A Polymorphism is Associated with the Risk of Ischemic Stroke in Chinese Type 2 Diabetic Patients
Authors: Chai Yi , Gu Bing , Qiu Jin‐Rong , Yi Hong‐Gang , Zhu Qian , Zhang Lu , Hu Gang
Published: May 2012

Aims: To determine genetic predispsitions for diabetic cerebral ischemia, we investigated the relationship between the ‐866G>A polymorphism of uncoupling protein (UCP) 2 and the risk of ischemic stroke in two cohorts of type 2 diabetic patients. Methods: A total of 844 type 2 diabetic patients with 4‐year prospective study were examined using a case‐control methodology. And 404 cases with ischemical stroke, 440 cases without ischemical stroke. The ‐866G>A polymorphism in UCP2 was genotyped by TaqMan MGB probe method. Results: The ‐866G>A SNP in UCP2 was significantly associated with diabetic ischemical stroke (odds ratio [OR]= 1.94; 95% confidence interval [CI]= 0.68 to1.31; P < 0.037). Similar results were observed for baseline cases of IS. Stratification by sex confirmed an allelic association with IS in women, whereas no association was observed in men. Conclusions: The A allele of the ‐866G>A variant of UCP2 was associated with increased risk of IS in Chinese diabetic women with type 2 diabetes in a 4‐year prospective study. This association was independent of other common IS risk factors.
Effect of Pregnancy and Obesity on Arch of Foot
Authors: Dunn John , Dunn Christina , Habbu Rohan , Bohay Donald , Anderson John
Published: May 2012

Objective

Endocrine changes occurring during pregnancy result in increased laxity of the ligaments of the foot. This may lead to gradual collapse of the foot arches. The aim of the study was to determine whether pregnancy and body mass index (BMI) had a role in affecting the foot arches at long term.

Methods

A collapsed arch results in widening of the feet, thus altering the foot size. The control group included nulliparous women, while the study group included women who had been pregnant at least once. The groups were stratified secondarily by obesity according to BMI. We reviewed over 1000 charts at the outpatient offices in a large Mid‐Western city. The age, BMI, and shoe size in an athletic shoe were recorded.

Results

There were 40 subjects in the control group and 70 in the study group. 19/40 women in control and 46/70 in study group experienced a change in shoe size (P = 0.06). Of those affected, the non‐obese control group experienced a 9.7% change in shoe size while the obese study group experienced a 15.5% change (P < 0.05).

Conclusion

There was neither a change in size between women who had been pregnant and the nulliparous, nor was there a difference between the obese and non‐obese. However, there was a statically significant difference between those affected who were both non‐obese and nulliparous and those who had been pregnant and who are obese. Individually, the effect of pregnancy and BMI are highly suggestive and clinically relevant.
Slope on Proximal Tibiofibular Articular Surface with 3‐D Reconstruction by 64‐Slice Computed Tomography on Human
Authors: Zhang Yin‐wang , Deng Hong‐zhen , Zhu Hai‐bo , Zhu Yi , Zhu Jian‐ming
Published: May 2012

Objective

Using 64‐slice spiral CT to reconstruct virtual knee joints of adults, we measured the gradient of proximal tibia‐fibular joint and compared this result with bare joint measurement. We then discuss the accuracy of these measurements using a 64‐slice spiral CT.

Methods

Two hundred healthy adults were selected, including 100 males and 100 females, aged from 18 to 90 years. The gradient of the longitudinal axis of the fibula and the articular surface, and the angle of horizon of the proximal tibia‐fibular articular surface and the horizontal line were measured by using a 64‐slice spiral CT scan.

Results

The angle between the longitudinal axis of the fibula and the articular surface (angle A) was 56.80° ± 6.59°, both the left and the right fibula showed no significant difference (t = 0.308, P = 0.758). The angle between horizontal line and the articular surface (angle B) was 32.80° ± 6.49°. The regression or correlation analysis findings showed that there is a negative relationship (r = −0.952, P = 0.000), and there is significant difference (t = 51.87, P < 0.01) between the angle A and the angle B.

Conclusion

The measurement value of using 64‐slice spiral CT to reconstruct the slope of proximal tibia‐fibular joints has no difference compared to the measurement value of the slope of bare proximal tibia‐fibular joints. It is a precise, convenient method and is easy to apply for clinical study.
Promising Trends in Access to Medicines
Authors: Richard Gold E. , Morin Jean‐Frédéric
Published: May 2012

It is a vast understatement to say that the problem of access to medicines in developing countries is complex. Access is limited by a range of factors including inability to pay, a lack of infrastructure, and corruption in some countries. Surrounding and exacerbating these structural and technological problems is the layer of legal rights created by patents and their licensing that complicate and render more expensive the preparation and delivery of needed medicines, particularly those that need to be adapted to the social, health and cultural environment of developing countries. This article provides a survey of innovative strategies that aim at maximizing the potential of patents to facilitate the development and delivery of medicines against diseases, the burden of which falls principally on developing country populations. To understand the context in which these strategies are being proposed and implemented, the article reviews the battles over access to medicines beginning in the late 1980s. It then surveys some of the principal suggestions put forward to better direct innovation systems in addressing the critical health needs of the world’s majority including advance market commitments, patent buy‐outs, prize funds, public–private partnerships and patent pools.
Global Inequality: From Class to Location, from Proletarians to Migrants
Authors: Milanovic Branko
Published: May 2012

Inequality between world citizens in the mid‐19th century was such that at least a half of it could be explained by income differences between workers and capital owners in individual countries. Real income of workers in most countries was similar and low. This was the basis on which Marxism built its universal appeal. More than 150 years later, in the early 21st century, the situation has changed fundamentally: more than 80 per cent of global income differences is due to large gaps in mean incomes between countries, and unskilled workers′ wages in rich and poor countries often differ by a factor of 10 to 1. This is the basis on which a new global political issue of migration has emerged because income differences between countries make individual gains from migration large. The key coming issue will be how to deal with this new challenge while acknowledging that migration is probably the most powerful tool for reducing global poverty and inequality.

Policy Implications

Immigration pressure is intimately related to high income gaps that exist between countries today.

Aid and immigration are complementary tools to deal with global poverty.

If recipient countries have trouble dealing with current migration flows, they should realize that the alternative is to help the growth of countries where most migrants come from. Aid is then seen to be also in rich countries’ own interest.

Such policies require a multilateral approach because of free rider problems.
A unified approach to multiple‐set canonical correlation analysis and principal components analysis
Authors: Hwang Heungsun , Jung Kwanghee , Takane Yoshio , Woodward Todd S.
Published: May 2012

Multiple‐set canonical correlation analysis and principal components analysis are popular data reduction techniques in various fields, including psychology. Both techniques aim to extract a series of weighted composites or components of observed variables for the purpose of data reduction. However, their objectives of performing data reduction are different. Multiple‐set canonical correlation analysis focuses on describing the association among several sets of variables through data reduction, whereas principal components analysis concentrates on explaining the maximum variance of a single set of variables. In this paper, we provide a unified framework that combines these seemingly incompatible techniques. The proposed approach embraces the two techniques as special cases. More importantly, it permits a compromise between the techniques in yielding solutions. For instance, we may obtain components in such a way that they maximize the association among multiple data sets, while also accounting for the variance of each data set. We develop a single optimization function for parameter estimation, which is a weighted sum of two criteria for multiple‐set canonical correlation analysis and principal components analysis. We minimize this function analytically. We conduct simulation studies to investigate the performance of the proposed approach based on synthetic data. We also apply the approach for the analysis of functional neuroimaging data to illustrate its empirical usefulness.
The effect of line‐up administrator blindness on the recording of eyewitness identification decisions
Authors: Rodriguez Dario N. , Berry Melissa A.
Published: May 2012

Purpose. Line‐up administrators’ expectations have been shown to influence eyewitnesses’ identification decisions. Expectations may also influence administrators’ willingness to record witnesses’ decisions as positive identifications.

Methods. Single‐ and double‐blind participant administrators presented a line‐up to a confederate witness, who identified either the suspect or a filler.

Results. A hierarchical log‐linear analysis revealed an interaction effect of blindness and witness choice on participants’ recording of the identification: Single‐blind administrators were more likely to record the confederate's choice as a positive identification when the witness chose the suspect (vs. a filler), whereas double‐blind administrators’ records were not influenced by the witness's choice. An interaction between blindness and witness choice also emerged for participant administrators’ witness evaluations. Single‐blind administrators rated confederates who chose a filler as significantly less credible than those who chose a suspect; double‐blind administrators’ ratings were consistent across photo selection.

Conclusions. Blindness influenced line‐up administrators’ record of line‐up outcomes. These results add to the growing body of research supporting the use of double‐blind line‐up administration.
Influence of menstrual cycle phase on muscle metaboreflex control of cardiac baroreflex sensitivity, heart rate and blood pressure in humans
Authors: Hartwich Doreen , Aldred Sarah , Fisher James P.
Published: May 2012

New Findings

What is the central question of this study?

Oestrogen has been reported to modify exercise‐induced autonomic responses and to impact on exercising skeletal muscle blood flow. Together, these oestrogenic influences might attenuate metabolite accumulation and muscle metaboreflex activation during exercise. Moreover, in dogs and in humans, the muscle metaboreflex has been reported to decrease cardiac baroreflex sensitivity during dynamic exercise.

What is the main finding and its importance?

Endogenous fluctuations in oestrogen between the early and late follicular phases of the menstrual cycle in healthy women, do not modify either the increase in heart rate and blood pressure or the reduction in spontaneous cardiac baroreflex sensitivity evoked by muscle metaboreflex activation.

We sought to determine whether menstrual cycle phase influences muscle metaboreflex control of spontaneous cardiac baroreflex sensitivity (cBRS), blood pressure (BP) and heart rate (HR). Twenty‐three young women not taking oral contraceptives were studied during the early (EF; low oestrogen, low progesterone) and late follicular menstrual phases (LF; high oestrogen, low progesterone). Protocol 1 consisted of leg cycling at low (21 ± 2 W) and moderate workloads (71 ± 3 W) in free‐flow conditions and with partial flow restriction (bilateral thigh‐cuff inflation at 100 mmHg) to activate the muscle metaboreflex. Protocol 2 consisted of rhythmic hand‐grip exercise with incremental upper arm‐cuff inflation (0, 80, 100 and 120 mmHg) to elicit graded metaboreflex activation. Both protocols were followed by post‐exercise ischaemia. Leg cycling decreased cBRS (EF, 20 ± 5, 6 ± 1 and 1 ± 0.1 ms mmHg−1; and LF, 19 ± 3, 6 ± 0.4, 1 ± 0.1 ms mmHg−1 during rest, low‐ and moderate‐intensity leg cycling, respectively) and increased HR in an intensity‐dependent manner, while BP remained unchanged. Partial flow restriction during leg cycling decreased cBRS, and increased HR and BP. During post‐exercise ischaemia, HR and BP remained elevated, while cBRS remained suppressed (EF, 4.2 ± 0.6 ms mmHg−1; and LF, 4.7 ± 0.5 ms mmHg−1; P < 0.05 versus rest). Cardiac baroreflex sensitivity was unchanged during hand‐grip with and without partial flow restriction and post‐exercise ischaemia. No differences in cBRS, HR or BP responses were observed between EF and LF at any time during either protocol. These data indicate that endogenous fluctuations in oestrogen between the EF and LF phases of the menstrual cycle do not influence muscle metaboreflex control of cBRS, BP or HR in young women.
A‐type K+ channels encoded by Kv4.2, Kv4.3 and Kv1.4 differentially regulate intrinsic excitability of cortical pyramidal neurons
Authors: Carrasquillo Yarimar , Burkhalter Andreas , Nerbonne Jeanne M.
Published: May 2012

Key points

A‐type K+ currents, IA, are key determinants of neuronal excitability. Previous studies suggest critical roles for voltage‐gated K+ (Kv) channel pore‐forming (α) subunits of the Kv4 subfamily in the generation of neuronal IA channels.

The experiments here examined directly the functional roles of Kv4.2, Kv4.3 and Kv1.4 in the regulation of the intrinsic excitability and the firing properties of mature cortical pyramidal (CP) neurons.

The results demonstrate roles for Kv4.2, Kv4.3 and Kv1.4 in the generation of IA channels and show that Kv4.2‐, Kv4.3‐ and Kv1.4‐encoded IA channels play distinct roles in regulating the intrinsic excitability and the firing properties of CP neurons.

These findings demonstrate previously unappreciated molecular and functional diversity of IA in central neurons, insights that will contribute importantly to future studies focused on determining the mechanisms underlying the alterations in neuronal excitability in epilepsy and other neurological disorders.

Abstract  Rapidly activating and rapidly inactivating voltage‐gated A‐type K+ currents, IA, are key determinants of neuronal excitability and several studies suggest a critical role for the Kv4.2 pore‐forming α subunit in the generation of IA channels in hippocampal and cortical pyramidal neurons. The experiments here demonstrate that Kv4.2, Kv4.3 and Kv1.4 all contribute to the generation of IA channels in mature cortical pyramidal (CP) neurons and that Kv4.2‐, Kv4.3‐ and Kv1.4‐encoded IA channels play distinct roles in regulating the intrinsic excitability and the firing properties of mature CP neurons. In vivo loss of Kv4.2, for example, alters the input resistances, current thresholds for action potential generation and action potential repolarization of mature CP neurons. Elimination of Kv4.3 also prolongs action potential duration, whereas the input resistances and the current thresholds for action potential generation in Kv4.3−/− and WT CP neurons are indistinguishable. In addition, although increased repetitive firing was observed in both Kv4.2−/− and Kv4.3−/− CP neurons, the increases in Kv4.2−/− CP neurons were observed in response to small, but not large, amplitude depolarizing current injections, whereas firing rates were higher in Kv4.3−/− CP neurons only with large amplitude current injections. In vivo loss of Kv1.4, in contrast, had minimal effects on the intrinsic excitability and the firing properties of mature CP neurons. Comparison of the effects of pharmacological blockade of Kv4‐encoded currents in Kv1.4−/− and WT CP neurons, however, revealed that Kv1.4‐encoded IA channels do contribute to controlling resting membrane potentials, the regulation of current thresholds for action potential generation and repetitive firing rates in mature CP neurons.
ROS and SOCE: recent advances and controversies in the regulation of STIM and Orai
Authors: Bogeski Ivan , Kilch Tatiana , Niemeyer Barbara A.
Published: May 2012

Abstract  Store‐operated Ca2+ entry (SOCE) is a widespread mechanism in cells to raise cytosolic Ca2+ and to refill Ca2+ stores. T cells critically rely on SOCE mediated by stromal interaction molecules (STIM) and Orai molecules for their activation and regulation of gene transcription; cells such as muscle cells, neurons or melanocytes probably utilize SOCE for the transmission of inducible receptor‐mediated function as well as for generalized Ca2+ homeostasis mechanisms. Exposure to environmental or cell‐intrinisic reactive oxygen species (ROS) can affect several components involved in Ca2+ homeostasis and thus alter multiple pathways. While all cells have a capacity to produce intracellular ROS, exposure of immune and skin cells to extracellular oxidative stress is particularly high during inflammation and/or with UV exposure. This review briefly summarizes cell‐intrinsic sources of ROS and focuses on current findings and controversies regarding the regulation of STIM and Orai by oxidative modifications. We also introduce melanocytes as a new model system to study the function of STIM and Orai isoforms under physiological conditions that include exposure to UV light as an activating stimulus.
The human carotid body transcriptome with focus on oxygen sensing and inflammation – a comparative analysis
Authors: Mkrtchian Souren , Kåhlin Jessica , Ebberyd Anette , Gonzalez Constancio , Sanchez Diego , Balbir Alexander , Kostuk Eric W , Shirahata Machiko , Fagerlund Malin Jonsson , Eriksson Lars I
Published: May 2012

Key points

The carotid body (CB) is the key oxygen sensor and governs the ventilatory response to hypoxia.

CB oxygen sensing and signalling gene expression is well described in animals whereas human data are absent.

Here we have characterized the human CB global gene expression in comparison with functionally related tissues and mouse CB gene expression.

We show that the human CB expresses oxygen sensing genes in common with mice but also differs on key genes such as certain K+ channels. There is moreover increased expression of inflammatory response genes in human and mouse CBs in comparison with related tissues.

The study establishes similarities but also important differences between animal and human CB gene expression profiles and provides a platform for future functional studies on human CBs.

Abstract  The carotid body (CB) is the key oxygen sensing organ. While the expression of CB specific genes is relatively well studied in animals, corresponding data for the human CB are missing. In this study we used five surgically removed human CBs to characterize the CB transcriptome with microarray and PCR analyses, and compared the results with mice data. In silico approaches demonstrated a unique gene expression profile of the human and mouse CB transcriptomes and an unexpected upregulation of both human and mouse CB genes involved in the inflammatory response compared to brain and adrenal gland data. Human CBs express most of the genes previously proposed to be involved in oxygen sensing and signalling based on animal studies, including NOX2, AMPK, CSE and oxygen sensitive K+ channels. In the TASK subfamily of K+ channels, TASK‐1 is expressed in human CBs, while TASK‐3 and TASK‐5 are absent, although we demonstrated both TASK‐1 and TASK‐3 in one of the mouse reference strains. Maxi‐K was expressed exclusively as the spliced variant ZERO in the human CB. In summary, the human CB transcriptome shares important features with the mouse CB, but also differs significantly in the expression of a number of CB chemosensory genes. This study provides key information for future functional investigations on the human carotid body.
Acute and chronic effects of carotid body denervation on ventilation and chemoreflexes in three rat strains
Authors: Mouradian Jr Gary C. , Forster Hubert V. , Hodges Matthew R.
Published: May 2012

Key points

Carbon dioxide (CO2) provides a major chemical stimulus to breathe, primarily through the activity of CO2/pH sensors called chemoreceptors in the brainstem and in the carotid body.

Carotid body denervation (CBD) causes hypoventilation at rest and reduces ventilatory sensitivity to CO2 in multiple mammalian species, suggesting an important role of the carotid bodies in determining levels of ventilation relative to the CO2 drive to breathe.

CBD in three strains of adult rats with large inherent differences in CO2 sensitivity causes hypoventilation at rest but has no effect on CO2 sensitivity.

These data from rats reinforce the concept that the carotid bodies provide a tonic facilitatory drive to breathe, but differ from other species suggesting a minimal contribution of the carotid bodies to CO2 sensitivity in rats.

Abstract  Brown Norway (BN) rats have a relatively specific deficit in CO2 sensitivity. This deficit could be due to an abnormally weak carotid body contribution to CO2 sensitivity. Accordingly, we tested the hypothesis that CBD would have less of an effect on eupnoeic breathing and CO2 sensitivity in the BN rats compared to other rat strains. We measured ventilation and blood gases at rest (eupnoea) and during hypoxia (= 0.12) or hypercapnia (= 0.07) before and up to 23 days after bilateral or Sham CBD in BN, Sprague–Dawley (SD) and Dahl Salt‐Sensitive (SS) rats. In all three rat strains, CBD elicited eupnoeic hypoventilation (Δ+8.7–11.0 mmHg) 1–2 days post‐CBD (P < 0.05), and attenuated ventilatory responses to hypoxia (P < 0.05) and venous sodium cyanide (NaCN; P < 0.05), while sham CBD had no effect on resting breathing, blood gases or chemoreflexes (P > 0.05). In contrast, CBD had no effect on CO2 sensitivity (Δ/Δ) in all strains (P > 0.05). Eupnoeic returned to pre‐CBD values within 15–23 days post‐CBD. Thus, the effects of CBD in rats (1) further support an important role for the carotid bodies in eupnoeic blood gas regulation, (2) suggest that the carotid bodies are not a major determinant of CO2 sensitivity in rats, and (3) may not support the concept of an interaction among the peripheral and central chemoreceptors in rats.
Multi-Objective Optimization of a Combined Power and Cooling Cycle for Low-Grade and Midgrade Heat Sources
Authors: Demirkaya Gokmen , Besarati Saeb , Vasquez Padilla Ricardo , Ramos Archibold Antonio , Goswami D. Yogi , Rahman Muhammad M. , Stefanakos Elias L.
Published: May 2012

Optimization of thermodynamic cycles is important for the efficient utilization of energy sources; indeed, it is more crucial for the cycles utilizing low-grade heat sources where the cycle efficiencies are smaller compared to high temperature power cycles. This paper presents the optimization of a combined power/cooling cycle, also known as the Goswami cycle, which combines the Rankine and absorption refrigeration cycles. The cycle uses a special binary fluid mixture as the working fluid and produces a power and refrigeration. In this regard, multi-objective genetic algorithms (GAs) are used for Pareto approach optimization of the thermodynamic cycle. The optimization study includes two cases. In the first case, the performance of the cycle is evaluated as it is used as a bottoming cycle and in the second case, as it is used as a top cycle utilizing solar energy or geothermal sources. The important thermodynamic objectives that have been considered in this work are, namely, work output, cooling capacity, effective first law, and exergy efficiencies. Optimization is carried out by varying the selected design variables, such as boiler temperature and pressure, rectifier temperature, and basic solution concentration. The boiler temperature is varied between 70–150 °C and 150–250 °C for the first and the second cases, respectively.
Hydrophobic Surface Effect on Heat Transfer Performance in an Oscillating Heat Pipe
Authors: Ji Yulong , Chen Hsiu-hung , Kim Young Jo , Yu Qingsong , Ma Xuehu , Ma H. B.
Published: May 2012

An experimental investigation of an oscillating heat pipe (OHP) with a superhydrophobic inner surface coated with a superhydrophobic self-assembled monolayer (SAM) of n-octadecyl mercaptan was conducted. The experimental results show that the oscillating motion in an OHP with a superhydrophobic surface can be generated and the OHP can function well. This is very different from the conventional wicked heat pipe, which cannot function if the inner surface is hydrophobic. The functionality of a superhydrophobic OHP is not sensitive to the wetting condition of the inner surface of the OHP. The investigation results in a better understating of heat transfer mechanism occurring in an OHP.
Can the Dean number Alone Characterize Flow Similarity in Differently Bent Tubes?
Authors: Cieślicki Krzysztof , Piechna Adam
Published: May 2012

Although flows of fluids in curved channels belong to a classical problem of fluid dynamics, most publications are restricted to investigations of flows in tube coils, or in single bends. This paper presents experimental and numerical (CFD) results concerning Newtonian flows in a set of multiple S-type bends of various orientations. Investigations were conducted for a wide range of Re values (0–3500) and for a significant curvature ratio lying between 0.05 and 0.29, which corresponds to De value falling within the range 0.02–1200. A coiled tube was also examined and treated as the reference geometry. It was shown, that despite a completely different velocity pattern, the nonlinear dependence of normalized flow resistance of wavy tubes and coiled tube of the same curvature ratio overlap within a significant range of De. A novel, close phenomenological formula to estimate the nonlinear flow resistance of tortuous tube in a wide range of De was proposed and compared with those in the literature. The conditions were also determined in which the De might be the only dimensionless group that characterizes such flows.
Performance Analysis of a Rankine Cycle Integrated With the Goswami Combined Power and Cooling Cycle
Authors: Vasquez Padilla Ricardo , Ramos Archibold Antonio , Demirkaya Gokmen , Besarati Saeb , Yogi Goswami D. , Rahman Muhammad M , Stefanakos Elias L.
Published: May 2012

Improving the efficiency of thermodynamic cycles plays a fundamental role in reducing the cost of solar power plants. These plants work normally with Rankine cycles which present some disadvantages due to the thermodynamic behavior of steam at low pressures. These disadvantages can be reduced by introducing alternatives such as combined cycles which combine the best features of each cycle. In this paper, a combined Rankine–Goswami cycle (RGC) is proposed and a thermodynamic analysis is conducted. The Goswami cycle, used as a bottoming cycle, uses ammonia–water mixture as the working fluid and produces power and refrigeration while power is the primary goal. This bottoming cycle, reduces the energy losses in the traditional condenser and eliminates the high specific volume and poor vapor quality presented in the last stages of the lower pressure turbine in the Rankine cycle. In addition, the use of absorption condensation in the Goswami cycle, for regeneration of the strong solution, allows operating the low pressure side of the cycle above atmospheric pressure which eliminates the need for maintaining a vacuum pressure in the condenser. The performance of the proposed combined Rankine–Goswami cycle, under full load, was investigated for applications in parabolic trough solar thermal plants for a range from 40 to 50 MW sizes. A sensitivity analysis to study the effect of the ammonia concentration, condenser pressure, and rectifier concentration on the cycle efficiency, network, and cooling was performed. The results indicate that the proposed RGC provide a difference in net power output between 15.7% and 42.3% for condenser pressures between 1 and 9 bars. The maximum effective first law and exergy efficiencies for an ammonia mass fraction of 0.5 are calculated as 36.7% and 24.7%, respectively, for the base case (no superheater or rectifier process).
Development and Validation of a Reduced Critical Radius Model for Cryogenic Cavitation
Authors: Tsuda Shin-ichi , Tani Naoki , Yamanishi Nobuhiro
Published: May 2012

Cryogenic fluids such as liquid hydrogen, liquid oxygen, and liquid methane have often been used as liquid rocket propellants, and it is well known that the suction performance of turbopump inducers is better in cryogenic fluids than it is in cold water due to the so-called “thermodynamic effect.” The origin of the thermodynamic effect is the temperature change inside a cavity region that arises from the latent heat transfer across the interface of a cavity. To better understand the suction performance of cavitating cryogenic inducers, we must take into account the temperature changes that take place due to the thermodynamic effect; computational fluid dynamics (CFD) analysis coupled with an energy equation is one of the most powerful tools for this purpose. The computational cost, however, becomes an obstacle for its application to the design phase, so a reduction in the number of governing equations is often preferable. In the present study, a cryogenic cavitation model that does not need to solve an energy equation is proposed as a reduced model; the model is named the “reduced critical radius model.” This model assumes that the temperature change due to the latent heat transfer can be analytically well estimated on the basis of an approximation of the local equilibrium when the pressure inside a cavity is always kept at a saturation vapor pressure at every temperature (at least on the time scale of the flow field). The proposed method was validated carefully for a variety of objects: blunt headforms, hydrofoils, a two-dimensional blunt wing, and Laval nozzles. The results obtained during the validation were in good agreement with the experimental results, except in the case of strong unsteady cavitation. This indicates that the present method, which does not involve solving an energy equation, offers good potential for application to the design phase of cryogenic cavitating inducers.
Numerical Analysis of Viscoelastic Fluids in Steady Pressure-Driven Channel Flow
Authors: Yapici Kerim , Karasozen Bulent , Uludag Yusuf
Published: May 2012

The developing steady flow of Oldroyd-B and Phan-Thien-Tanner (PTT) fluids through a two-dimensional rectangular channel is investigated computationally by means of a finite volume technique incorporating uniform collocated grids. A second-order central difference scheme is employed to handle convective terms in the momentum equation, while viscoelastic stresses are approximated by a third-order accurate quadratic upstream interpolation for convective kinematics (QUICK) scheme. Momentum interpolation method (MIM) is used to evaluate both cell face velocities and coefficients appearing in the stress equations. Coupled mass and momentum conservation equations are then solved through an iterative semi-implicit method for pressure-linked equation (SIMPLE) algorithm. The entry length over which flow becomes fully developed is determined by considering gradients of velocity, normal and shear stress components, and pressure in the axial direction. The effects of the mesh refinement, inlet boundary conditions, constitutive equation parameters, and Reynolds number on the entry length are presented.
Time-Dependent Deposition of Micro- and Nanofibers in Straight Model Airways
Authors: Högberg Sofie M. , Åkerstedt Hans O. , Holmstedt Elise , Staffan Lundström T. , Sandström Thomas
Published: May 2012

In this paper, we increase the understanding of the influence of the breathing pattern on the fate of inhaled non-spherical micro and nanoparticles and examine the accuracy of replacing the cyclic flow field with a quasi-steady flow. This is done with new analysis and numerical simulations on straight model airways using a previously developed discrete model for fiber motion. For the conditions studied, maximum deposition is obtained when fibers are released at the start of the inspiratory cycle, and minimum is received at the peak of inhalation. A quasi-steady solution generally provides a relatively good approximation to cyclic flow if an average velocity over one residence time of the particles moving with the mean fluid velocity is used. For a batch type, supply of particles deposition is favored in light activity breathing as compared to heavy breathing and the inclusion of a short pause after the inhalation results in an increased deposition in the terminal bronchiole. During zero-flow over the time of a breathing pause, spherical 10 nm particles experience considerable deposition in the distal airways, whereas only a few percent of larger and/ or fibrous nanoparticles were deposited. Hence, size and shape are crucial variables for deposition for no flow conditions. Common for all breathing parameters examined was that minimum deposition was obtained for the spherical 1 μm-particles and the fibrous 100 nm-particles. The former is expected from studies on spherical particles, and the latter is in agreement with results from a recent publication on steady inspiration.
The Effects of a Tripped Turbulent Boundary Layer on Vortex Shedding from a Blunt Trailing Edge Hydrofoil
Authors: Ausoni Philippe , Zobeiri Amirreza , Avellan François , Farhat Mohamed
Published: May 2012

Experiments on vortex shedding from a blunt trailing edge symmetric hydrofoil operating at zero angle of attack in a uniform high speed flow, Reh=16.1·103-96.6·103, where the reference length h is the trailing edge thickness, are reported. The effects of a tripped turbulent boundary layer on the wake characteristics are analyzed and compared with the condition of a natural turbulent transition. The foil surface is hydraulically smooth and a fully effective boundary layer tripping at the leading edge is achieved with the help of a distributed roughness. The vortex shedding process is found to be strongly influenced by the boundary layer development: the tripped turbulent transition promotes the re-establishment of organized vortex shedding. In the context of the tripped transition and in comparison with the natural one, significant increases in the vortex span-wise organization, the vortex-induced hydrofoil vibration, the wake velocity fluctuations, and the vortex strength are revealed. Although the vortex shedding frequency is decreased, a modified Strouhal number based on the wake width at the end of the vortex formation region is constant and evidences the similarity of the wakes in terms of spatial distribution for the two considered boundary layer transition processes.