bluuebunny/crossref_metadata_2025 huggingface dataset:
Childhood facial vitiligo: how intractable is it?
Authors: Kim S. A. , Cho S. , Kwon S. H. , Park J. T. , Na J. I. , Huh C. H. , Park K. C.
Published: August 2014

Background

Following the recent elucidation of its pathogenic mechanisms involving reactive oxygen species, use of vitamins, folic acid and antioxidants as adjuvant therapy has been suggested.

Objective

To evaluate the long‐term outcome of childhood facial vitiligo who were treated with nutritional education, vitamin E (α‐tocopherol 100–400 IU/day), folic acid (1–2 mg/day) and multivitamin intake and antioxidant cosmetics as the mainstay of treatment as well as the conventional therapies including oral, topical and/or intralesional corticosteroid, topical macrolactam, Excimer laser and epidermal graft.

Methods

Medical data and photographs of 111 paediatric facial vitiligo patients who had been followed up for longer than 1 year from March 1, 2003 to June 30, 2013 were extracted from data warehouse of electric medical records. Photographic evaluation and final visual outcome assessment was performed.

Result

By investigator's assessment, 9% of patients demonstrated no improvement regardless of treatment modality, whereas 91% showed improvement of lesions. Among the latter, 33.3% resulted in >75% improvement; 18% in 50%–75% improvement; 26.1% in 25%–50% improvement; and 13.5% in <25% improvement. In the final visual outcome assessment, ‘Looking excellent’ was seen in 42.3%; ‘looking very good’ in 30.6%; ‘looking good’ in 17.1%; ‘looking fair’ in 9.0%; and ‘looking bad’ in 0.9%.

Conclusion

Although childhood facial vitiligo is quite refractory to treatment, the long‐term outcome of this condition is not dismal with conventional vitiligo therapy along with basic nutritional therapeutic regimen.
Radiation‐induced morphea – a literature review
Authors: Spalek M. , Jonska‐Gmyrek J. , Gałecki J.
Published: August 2014

Radiation‐induced morphea (RIM) is a rare and under‐recognized skin complication of radiotherapy. It is commonly wrongly diagnosed as other dermatological conditions or malignancy because of similar clinical characteristics. This literature review analyses 66 cases that have been reported in the literature since 1989. The clinical appearance often includes pain and disfiguration of affected area, which may influence the patient's quality of life. There is no clear connection between the radiotherapy dose, the fractionation scheme, the use of a boost, age, the presence of other dermatological conditions or other connective tissue diseases and the occurrence of RIM. Its pathogenesis is still unclear, but several theories are proposed to explain this phenomenon. The available data suggest that the abnormally high secretion of some cytokines (interleukin 4, interleukin 5, transforming growth factor) induced by radiation causes an extensive fibrosis after an activation of fibroblasts. Histological confirmation is crucial in distinguishing RIM from similar‐looking diseases, such as chronic radiation dermatitis, cancer recurrence, radiation, recall dermatitis, new carcinoma or cellulitis. There is no clear treatment regimen for this condition. Clinical outcome after therapy is often unsatisfactory. The commonly used methods and agents include: topical and systemic steroids, calcineurin inhibitors, systemic immunosuppressants including methotrexate, tacrolimus, heparin, hyaluronidase, phototherapy (UVA, UVA1, UVB, PUVA), systemic antibiotics, imiquimod, mycophenolate mofetil, photophoresis. The differential diagnosis is challenging and requires a multidisciplinary approach to avoid misdiagnosis and to plan appropriate treatment.
Serum enolase: a non‐destructive biomarker of white skeletal myopathy during pancreas disease (PD) in Atlantic salmon Salmo salar L.
Authors: Braceland M , McLoughlin M F , Tinsley J , Wallace C , Cockerill D , McLaughlin M , Eckersall P D
Published: August 2014

Diseases which cause skeletal muscle myopathy are some of the most economically damaging diseases in Atlantic salmon, Salmo salar L., aquaculture. Despite this, there are limited means of assessing fish health non‐destructively. Previous investigation of the serum proteome of Atlantic salmon, Salmo salar L., during pancreas disease (PD) has identified proteins in serum that have potential as biomarkers of the disease. Amongst these proteins, the enzyme enolase was selected as the most viable for use as a biomarker of muscle myopathy associated with PD. Western blot and immunoassay (ELISA) validated enolase as a biomarker for PD, whilst immunohistochemistry identified white muscle as the source of enolase. Enolase was shown to be a specific marker for white muscle myopathy in salmon, rising in serum concentration significantly correlating with pathological damage to the tissue.
Income inequality, disinvestment in health care and use of dental services
Authors: Bhandari Bishal , Newton Jonathan T. , Bernabé Eduardo
Published: August 2014

Objective

To explore the interrelationships between income inequality, disinvestment in health care, and use of dental services at country level.

Methods

This study pooled national estimates for use of dental services among adults aged 18 years or older from the 70 countries that participated in the World Health Survey from 2002 to 2004, together with aggregate data on national income (GDP per capita), income inequality (Gini coefficient), and disinvestment in health care (total health expenditure and dentist‐to‐population ratio) from various international sources. Use of dental services was defined as having had dental problems in the last 12 months and having received any treatment to address those needs. Associations between variables were explored using Pearson correlation coefficients and linear regression.

Results

Data from 63 countries representing the six WHO regions were analyzed. Use of dental services was negatively correlated with Gini coefficient (Pearson correlation coefficient −0.48, P < 0.001) and positively correlated with GDP per capita (0.40, P < 0.05), total health expenditure (0.45, P < 0.001), and dentist‐to‐population ratio (0.67, P < 0.001). The association between Gini coefficient and use of dental services was attenuated but remained significant after adjustments for GDP per capita, total health expenditure, and dentist‐to‐population ratio (regression coefficient −0.36; 95% CI −0.57, −0.15).

Conclusion

This study shows an inverse relationship between income inequality and use of dental services. Of the two indicators of disinvestment in health care assessed, only dentist‐to‐population ratio was associated with income inequality and use of dental services.
A Critical Analysis of Candidacy for Penile Revascularization
Authors: Dabaja Ali A. , Teloken Patrick , Mulhall John P.
Published: August 2014

Introduction

Penile revascularization (PR) is a potentially curative procedure for young men with isolated arteriogenic erectile dysfunction. Standard preoperative evaluation is erectile hemodynamics (HDX) using duplex Doppler penile ultrasound (DUS) and/or cavernosometry (DIC) and assessment of cavernosal arterial anatomy by selective internal pudendal arteriography (SIPA).

Aim

The aim of this study was to review our experience with men who sought a second opinion from us regarding their candidacy for PR.

Method

Study population consisted of men (i) who presented to us for a second opinion regarding PR; (ii) who had DUS/DIC and SIPA; and (iii) had been advised by outside surgeon to undergo PR. Review of the HDX study and SIPA was conducted. Discrepancies between these studies resulted in repeating the DIC in men with normal SIPA or repeating the SIPA in men with normal HDX studies.

Main Outcome Measures

Discrepancies between HDX and SIPA and the results of repeat HDX or SIPA were the main outcome measures.

Result

Forty-five patients participated in the study; mean age was 33 years with 4% ≥50 years old. Median vascular risk factor number was 1 (ranged 0–3). A credible trauma history was present in 11%. Thirty-three percent had prior DIC and 49% of patients had a significant discrepancy between HDX study and SIPA, including all patients seen by a community urologist. Thirty-eight percent had a discrepancy between side of abnormality on HDX and SIPA where both studies were abnormal (group A). Seven percent had abnormal HDX and normal SIPA (group B). Four percent had a normal HDX study with an abnormal SIPA (group C). Repeat DIC (n = 20) was conducted in groups A + B and was normal in 70% of cases. Repeat SIPA (n = 2) was conducted in group C and was normal in both patients.

Conclusion

Almost one half of patients had a significant discrepancy between HDX and SIPA. Of these, 73% had normal repeat studies, making them no longer candidates for penile revascularization.
Activation and polar sequestration of PopA, a c‐di‐GMP effector protein involved in Caulobacter crescentus cell cycle control
Authors: Ozaki Shogo , Schalch‐Moser Annina , Zumthor Ludwig , Manfredi Pablo , Ebbensgaard Anna , Schirmer Tilman , Jenal Urs
Published: August 2014

When Caulobacter crescentus enters S‐phase the replication initiation inhibitor CtrA dynamically positions to the old cell pole to be degraded by the polar ClpXP protease. Polar delivery of CtrA requires PopA and the diguanylate cyclase PleD that positions to the same pole. Here we present evidence that PopA originated through gene duplication from its paralogue response regulator PleD and subsequent co‐option as c‐di‐GMP effector protein. While the C‐terminal catalytic domain (GGDEF) of PleD is activated by phosphorylation of the N‐terminal receiver domain, functional adaptation has reversed signal transduction in PopA with the GGDEF domain adopting input function and the receiver domain serving as regulatory output. We show that the N‐terminal receiver domain of PopA specifically interacts with RcdA, a component required for CtrA degradation. In contrast, the GGDEF domain serves to target PopA to the cell pole in response to c‐di‐GMP binding. In agreement with the divergent activation and targeting mechanisms, distinct markers sequester PleD and PopA to the old cell pole upon S‐phase entry. Together these data indicate that PopA adopted a novel role as topology specificity factor to help recruit components of the CtrA degradation pathway to the protease specific old cell pole of C. crescentus.
A transcriptional co‐repressor regulatory circuit controlling the heat‐shock response of Mycobacterium tuberculosis
Authors: Singh Ranjeet , Anil Kumar Vijjamarri , Das Arijit Kumar , Bansal Roohi , Sarkar Dibyendu
Published: August 2014

The co‐ordinated regulation of heat shock proteins is critically important for the stress response of M. tuberculosis, failure of which results in enhanced immune recognition of the tubercle bacilli with reduced survival during chronic infections. In this study, we show that PhoP regulates the transcription of α‐crystallin 2 (acr2), expression of which increases more than any other gene of M. tuberculosis during heat‐shock or following macrophage infection. We also show that regulation of acr2 by PhoP is attributable to direct regulator‐promoter interactions at specific sites proximal to a sequence motif comprising the target site of another virulence factor, HspR. While both these regulators, on their own, are capable of influencing acr2 expression, remarkably our results show that the two virulence regulators PhoP and HspR interact with each other to influence their in vivo recruitment at the acr2 regulatory region, and in turn, contribute to stress‐specific regulation of acr2 expression. We propose a model to suggest how protein–protein interactions between PhoP and HspR influence the regulation of α‐crystallin 2, an essential pathogenic determinant of M. tuberculosis.
The toolbox of Trichoderma spp. in the biocontrol of Botrytis cinerea disease
Authors: Vos Christine M. F. , De Cremer Kaat , Cammue Bruno P. A. , De Coninck Barbara
Published: August 2014

Botrytis cinerea is a necrotrophic fungal pathogen causing disease in many plant species, leading to economically important crop losses. So far, fungicides have been widely used to control this pathogen. However, in addition to their detrimental effects on the environment and potential risks for human health, increasing fungicide resistance has been observed in the B. cinerea population. Biological control, that is the application of microbial organisms to reduce disease, has gained importance as an alternative or complementary approach to fungicides. In this respect, the genus Trichoderma constitutes a promising pool of organisms with potential for B. cinerea control. In the first part of this article, we review the specific mechanisms involved in the direct interaction between the two fungi, including mycoparasitism, the production of antimicrobial compounds and enzymes (collectively called antagonism), and competition for nutrients and space. In addition, biocontrol has also been observed when Trichoderma is physically separated from the pathogen, thus implying an indirect systemic plant defence response. Therefore, in the second part, we describe the consecutive steps leading to induced systemic resistance (ISR), starting with the initial Trichoderma–plant interaction and followed by the activation of downstream signal transduction pathways and, ultimately, the defence response resulting in ISR (ISR‐prime phase). Finally, we discuss the ISR‐boost phase, representing the effect of ISR priming by Trichoderma spp. on plant responses after additional challenge with B. cinerea.
A standard cytogenetic map for Anopheles sinensis and chromosome arm homology between the subgenera Anopheles and Cellia
Authors: LIANG J. , SHARAKHOVA M. V. , LAN Q. , ZHU H. , SHARAKHOV I. V. , XIA A.
Published: August 2014

Anopheles sinensis (Diptera: Culicidae) is an important vector of Plasmodium vivax in Southeast Asia. To facilitate population genetic and genomic studies of An. sinensis, we developed a standard cytogenetic photomap for this species. The polytene chromosomes were straightened and divided into 39 numbered divisions and 116 lettered subdivisions. The chromosomal localizations of 13 DNA probes were determined by fluorescent in situ hybridization. A comparison of the physical map for An. sinensis with the genome map for Anopheles gambiae revealed a whole‐arm autosomal translocation between the two species. Specifically, the 2R arm of An. gambiae corresponds to the 3R arm of An. sinensis and the pattern of correspondence of the other chromosome arms remains regular. We mapped the breakpoints of the polymorphic paracentric chromosomal inversion 3Ra to subdivisions 28A and 31A. The standard cytogenetic map developed in this study will be useful for detailed comparative genome mapping and population genetic studies of An. sinensis.
Phlebotomus (Paraphlebotomus) riouxi: a synonym of Phlebotomus chabaudi without any proven vectorial role in Tunisia and Algeria
Authors: TABBABI A. , RHIM A. , GHRAB J. , MARTIN O. , AOUN K. , BOURATBINE A. , READY P. D.
Published: August 2014

Phlebotomus (Paraphlebotomus) riouxi Depaquit, Léger & Killick‐Kendrick (Diptera: Psychodidae) was described as a typological species based on a few morphological characters distinguishing it from Phlebotomus (Paraphlebotomus) chabaudi Croset, Abonnenc & Rioux. The naming of P. riouxi coincided with its incrimination as a rural vector of Leishmania tropica Wright (junior synonym: Leishmania killicki Rioux, Lanotte & Pratlong) in Tataouine governorate, an arid region of southern Tunisia. The current report finds insufficient evidence to incriminate either phlebotomine sandfly as a vector of L. tropica in North Africa. Phlebotomus riouxi was found not to have the characteristics of a phylogenetic or biological species, and therefore it is synonymized with P. chabaudi. Both taxa were recorded together for the first time in Tunisia, in Tataouine, where three of 12 males showed intermediate morphology and both sexes of each taxon were not characterized by specific lineages of the nuclear gene elongation factor‐1α or the mitochondrial gene cytochrome b, for which a long 3′ terminal fragment is recommended for phlebotomine phylogenetics. This case study indicates that the eco‐epidemiology of leishmaniasis should focus more on identifying key components of vectorial transmission that are susceptible to interventions for disease control, rather than on defining sibling species of vectors.
Hybridization studies to modify the host preference of Anopheles gambiae
Authors: PATES H. V. , CURTIS C. F. , TAKKEN W.
Published: August 2014

A strategy to decrease the vector competence of Anopheles gambiae sensu stricto (Diptera: Culicidae), the most efficient malaria vector in Africa, may consist of exploiting the genes involved in zoophily. Crossing and backcrossing experiments were performed between An. gambiae s.s. and the zoophilic sibling species Anopheles quadriannulatus. Mosquito strains were tested in a dual‐choice olfactometer to investigate their responses to cow odour. Totals of 12% of An. gambiae s.s. and 59% of An. quadriannulatus selected the port with the cow odour. Crosses and backcrosses did not show a significant preference for the cow‐baited port. The results indicated that anthropophilic behaviour in An. gambiae s.s. is a dominant or partially dominant trait, which, in conjunction with the unstable zoophilic behaviour observed in An. quadriannulatus, poses a serious obstacle to plans to decrease vector competence by modifying the anthropophilic trait.
Antigen characterization from second instars of oestrid bot flies for the detection of anti‐Cephenemyia stimulator antibodies by ELISA in roe deer (Capreolus capreolus)
Authors: ARIAS M. S. , PAJARES G. , PAZ‐SILVA A. , DÍEZ‐BAÑOS N. , SUÁREZ J. L. , DÍEZ‐BAÑOS P. , SÁNCHEZ‐ANDRADE R. , MORRONDO P.
Published: August 2014

A study to determine the most appropriate antigen for use in the serodiagnosis of Cephenemyia (Diptera: Oestridae) infestation in roe deer (Capreolus capreolus) was carried out using immunoenzymatic tests. Serum samples from 43 roe deer from northern Spain were obtained post‐mortem and corresponding numbers of bot fly larvae established. Three antigen complexes were tested, including Cephenemyia stimulator Clark excretory/secretory antigens (CsES), C. stimulator somatic antigens (CsSA) and Oestrus ovis L. (Diptera: Oestridae) excretory/secretory antigens (OoES). In addition, the composition of each antigen was analysed using an electrophoresis system. Cephenemyia stimulator larvae were found in 25% of roe deer; the mean intensity of infection was 24.3 larvae per infested animal. In the antigen analysis, CsSA showed four exclusive bands of molecular weight (17–19, 62, 65 and 67–70 kDa). A positive correlation between immunoglobulin G (IgG) values and total number of larvae was found with CsES and CsSA. The highest sensitivity value, negative predictive value and negative likelihood ratio were obtained using CsES. The highest specificity value, positive likelihood ratio and kappa value were achieved with CsSA. The predictive values of the enzyme‐linked immunosorbent assay (ELISA) using CsES and CsSA reached statistical significance and seroprevalence values were 26–44%. The use of ELISA with CsES and CsSA seems promising in the non‐invasive diagnosis of Cephenemyia infestation in roe deer.
Overexpression of a rice heme activator protein gene (OsHAP2E) confers resistance to pathogens, salinity and drought, and increases photosynthesis and tiller number
Authors: Alam Md. Mahfuz , Tanaka Toru , Nakamura Hidemitsu , Ichikawa Hiroaki , Kobayashi Kappei , Yaeno Takashi , Yamaoka Naoto , Shimomoto Kota , Takayama Kotaro , Nishina Hiroshige , Nishiguchi Masamichi
Published: August 2014

Heme activator protein (HAP), also known as nuclear factor Y or CCAAT binding factor (HAP/NF‐Y/CBF), has important functions in regulating plant growth, development and stress responses. The expression of rice HAP gene (OsHAP2E) was induced by probenazole (PBZ), a chemical inducer of disease resistance. To characterize the gene, the chimeric gene (OsHAP2E::GUS) engineered to carry the structural gene encoding β‐glucuronidase (GUS) driven by the promoter from OsHAP2E was introduced into rice. The transgenic lines of OsHAP2Ein::GUS with the intron showed high GUS activity in the wounds and surrounding tissues. When treated by salicylic acid (SA), isonicotinic acid (INA), abscisic acid (ABA) and hydrogen peroxide (H2O2), the lines showed GUS activity exclusively in vascular tissues and mesophyll cells. This activity was enhanced after inoculation with Magnaporthe oryzae or Xanthomonas oryzae pv. oryzae. The OsHAP2E expression level was also induced after inoculation of rice with M. oryzae and X. oryzae pv. oryzae and after treatment with SA, INA, ABA and H2O2, respectively. We further produced transgenic rice overexpressing OsHAP2E. These lines conferred resistance to M. oryzae or X. oryzae pv. oryzae and to salinity and drought. Furthermore, they showed a higher photosynthetic rate and an increased number of tillers. Microarray analysis showed up‐regulation of defence‐related genes. These results suggest that this gene could contribute to conferring biotic and abiotic resistances and increasing photosynthesis and tiller numbers.
Changes in Income Predict Change in Social Trust: A Longitudinal Analysis
Authors: Brandt Mark J. , Wetherell Geoffrey , Henry P. J.
Published: August 2014

Social trust is a psychological variable important to politics, the community, and health. Theorists have predicted that socioeconomic status determines social trust, but also that social trust determines socioeconomic status. The current study tested the viability of both causal directions using longitudinal data from representative samples of the United States and the United Kingdom. Results demonstrated that a model where increases in socioeconomic status (measured by income) predict increases in social trust is more viable than a model where increases in social trust predict increases in socioeconomic status.
The incidence of lung cancer by histological type: A population‐based study in Tianjin, China during 1981–2005
Authors: Kong Jinyu , Xu Fangxiu , He Min , Chen Kexin , Qian Biyun
Published: August 2014

Background and objective

Lung cancer remains the leading cause of cancer deaths worldwide. The aim of this study was to examine the trend in the incidence of lung cancer, validated by histology in Tianjin, the third largest municipal city in China, during the period from 1981 to 2005.

Methods

New lung cancer cases, crude incidence rates and age‐adjusted rates by histological type were analysed using the data from the Tianjin Cancer Registry, which covers a population of 4 million urban residents.

Results

The most common histological types of lung cancer were squamous cell carcinoma (SQCC) in men and adenocarcinoma (ADC) in women. During the 25‐year period, the constitutive pattern of the histological types changed gradually, ADC increased by 31.4%, but SQCC decreased by 25.6% among women. For SQCC, ADC or small cell carcinoma (SMCC), both the new cases and crude incidences per year increased among men and women. However, the age‐adjusted incidences of all types of lung cancer showed an initial increase, which then levelled off or declined in recent years. The birth‐cohort incidence analyses revealed that SQCC declined sharply, while ADC still increased among the younger age groups.

Conclusion

The incidences of lung cancer by histological type changed during the 25‐year period in Tianjin. Tailored strategies on prevention and control should be developed to meet the needs for various populations.
Galois module structure and Jacobians of Fermat curves
Authors: Cassou‐Noguès Philippe , Gillibert Jean , Jehanne Arnaud
Published: August 2014

The class‐invariant homomorphism allows one to measure the Galois module structure of extensions obtained by dividing points on abelian varieties. In this paper, we consider the case when the abelian variety is the Jacobian of a Fermat curve. We give examples of torsion points whose associated Galois structure is trivial, as well as points of infinite order whose associated Galois structure is non‐trivial.
Characterization of butyrate transport across the luminal membranes of equine large intestine
Authors: Nedjadi Taoufik , Moran Andrew W. , Al‐Rammahi Miran A. , Shirazi‐Beechey Soraya P.
Published: August 2014

New Findings

What is the central question of this study?

Butyrate, a product of colonic microbial fermentation of dietary fibre (grass), is a major source of energy for the horse and plays an important role in maintaining the health of the intestine. What are the properties of the membrane protein and what is the mechanism by which butyrate is absorbed in equine large intestine (colon)?

What is the main finding and its importance?

We have identified the mechanism of and membrane protein involved in butyrate transport in equine large intestine. This knowledge will allow rational approaches to the design of dietary formulations to enhance butyrate production and absorption in equine colon, in order to provide more energy for the horse and maintain its gut health.

The diet of the horse, pasture forage (grass), is fermented by the equine colonic microbiota to short‐chain fatty acids, notably acetate, propionate and butyrate. Short‐chain fatty acids provide a major source of energy for the horse and contribute to many vital physiological processes. We aimed to determine both the mechanism of butyrate uptake across the luminal membrane of equine colon and the nature of the protein involved. To this end, we isolated equine colonic luminal membrane vesicles. The abundance and activity of cysteine‐sensitive alkaline phosphatase and villin, intestinal luminal membrane markers, were significantly enriched in membrane vesicles compared with the original homogenates. In contrast, the abundance of GLUT2 protein and the activity of Na+–K+‐ATPase, known markers of the intestinal basolateral membrane, were hardly detectable. We demonstrated, by immunohistochemistry, that monocarboxylate transporter 1 (MCT1) protein is expressed on the luminal membrane of equine colonocytes. We showed that butyrate transport into luminal membrane vesicles is energized by a pH gradient (out < in) and is not Na+ dependent. Moreover, butyrate uptake is time and concentration dependent, with a Michaelis–Menten constant of 5.6 ± 0.45 mm and maximal velocity of 614 ± 55 pmol s−1 (mg protein)−1. Butyrate transport is significantly inhibited by p‐chloromercuribenzoate, phloretin and α‐cyano‐4‐hydroxycinnamic acid, all potent inhibitors of MCT1. Moreover, acetate and propionate, as well as the monocarboxylates pyruvate and lactate, also inhibit butyrate uptake. Data presented here support the conclusion that transport of butyrate across the equine colonic luminal membrane is predominantly accomplished by MCT1.
Reduced hypoxic ventilatory response in newborn mice knocked‐out for the progesterone receptor
Authors: Potvin Catherine , Rossignol Orlane , Uppari NagaPraveena , Dallongeville Arnaud , Bairam Aida , Joseph Vincent
Published: August 2014

New Findings

What is the central question of this study?

Progesterone has been proposed as an alternative to xanthine therapy for the treatment of idiopathic apnoeas in preterm neonates, but our knowledge of the respiratory function of progesterone in neonates is limited. We therefore asked whether endogenous progesterone is an efficient respiratory stimulant in newborn mice.

What is the main finding and its importance?

The present study shows that expression of the nuclear progesterone receptor is a key contributor to the hypoxic ventilatory response in newborn mice. This study will encourage further research on the role of other progesterone receptors in respiratory control in newborn mammals.

Recent studies showed that progesterone stimulates the hypoxic ventilatory response and may reduce apnoea frequency in newborn rats, but so far we still do not know by what mechanisms and whether endogenous progesterone might contribute to respiratory control in neonates. We therefore determined the role of the nuclear progesterone receptor (PR; member of the steroid receptor superfamily) by using wild‐type (WT) and PR knock‐out (PRKO) mice at postnatal days (P) 1, 4 and 10. We measured the hypoxic ventilatory response (14 and 12% O2, 20 min each) and apnoea frequency in both male and female mice by using whole‐body plethysmography. In response to hypoxia, WT male mice had a marked hypoxic ventilatory response at P1 and P10, but not at P4. At P1 and P10, PRKO male mice had a lower hypoxic ventilatory response than WT males. Wild‐type female mice had a marked hypoxic ventilatory response at P10, but not at P1 and P4. At P1 and P10, PRKO female mice had a lower hypoxic ventilatory response than WT females. In basal conditions, apnoea frequency was similar in WT and PRKO mice at P1, P4 and P10. During hypoxia, apnoea frequency was higher in WT male mice compared with PRKO male mice and WT female mice at P1. We conclude that PR is a key contributor to the hypoxic ventilatory response in newborn mice, but PR deletion does not increase the frequency of apnoea during normoxia or hypoxia.
Spinal μ‐opioid receptor‐sensitive lower limb muscle afferents determine corticospinal responsiveness and promote central fatigue in upper limb muscle
Authors: Sidhu Simranjit K. , Weavil Joshua C. , Venturelli Massimo , Garten Ryan S. , Rossman Matthew J. , Richardson Russell S. , Gmelch Benjamin S. , Morgan David E. , Amann Markus
Published: August 2014

Key points

We aimed to elucidate the role of group III/IV locomotor muscle afferents in the development of central fatigue and the responsiveness of the corticospinal tract in relation to an unexercised arm muscle.

Intrathecal fentanyl, a μ‐opioid receptor agonist, was employed to attenuate afferent feedback from the leg muscles during intense cycling exercise characterized by either no or severe peripheral locomotor muscle fatigue.

In the absence of locomotor muscle fatigue, group III/IV‐mediated leg afferent feedback facilitates the responsiveness of the motor pathway to upper limb flexor muscles.

By contrast, in the presence of leg fatigue, group III/IV locomotor muscle afferents facilitate supraspinal fatigue in a remote muscle not involved in the exercise and disfacilitate the responsiveness of associated corticospinal projections.

We investigated the influence of group III/IV lower limb muscle afferents on the development of supraspinal fatigue and the responsiveness of corticospinal projections to an arm muscle. Eight males performed constant‐load leg cycling exercise (80% peak power output) for 30 s (non‐fatiguing) and to exhaustion (∼9 min; fatiguing) both under control conditions and with lumbar intrathecal fentanyl impairing feedback from μ‐opioid receptor‐sensitive lower limb muscle afferents. Voluntary activation (VA) of elbow flexors was assessed via transcranial magnetic stimulation (TMS) during maximum voluntary contraction (MVC) and corticospinal responsiveness was monitored via TMS‐evoked potentials (MEPs) during a 25% MVC. Accompanied by a significant 5 ± 1% reduction in VA from pre‐ to post‐exercise, elbow flexor MVC progressively decreased during the fatiguing trial (P < 0.05). By contrast, with attenuated feedback from locomotor muscle afferents, MVC and VA remained unchanged during fatiguing exercise (P > 0.3). MEPs decreased by 36 ± 6% (P < 0.05) from the start of exercise to exhaustion under control conditions, but this reduction was prevented with fentanyl blockade. Furthermore, fentanyl blockade prevented the significant increase in elbow flexor MEP observed from rest to non‐fatiguing exercise under control conditions and resulted in a 14% lower corticospinal responsiveness during this short bout (P < 0.05). Taken together, in the absence of locomotor muscle fatigue, group III/IV‐mediated leg muscle afferents facilitate responsiveness of the motor pathway to upper limb flexor muscles. By contrast, in the presence of cycling‐induced leg fatigue, group III/IV locomotor muscle afferents facilitate supraspinal fatigue in remote muscle not involved in the exercise and disfacilitate, or inhibit, the responsiveness of corticospinal projections to upper limb muscles.
Flutter Amplitude Saturation by Nonlinear Friction Forces: Reduced Model Verification
Authors: Martel Carlos , Corral Roque , Ivaturi Rahul
Published: August 2014

The computation of the final, friction saturated limit cycle oscillation amplitude of an aerodynamically unstable bladed-disk in a realistic configuration is a formidable numerical task. In spite of the large numerical cost and complexity of the simulations, the output of the system is not that complex: it typically consists of an aeroelastically unstable traveling wave (TW), which oscillates at the elastic modal frequency and exhibits a modulation in a much longer time scale. This slow time modulation over the purely elastic oscillation is due to both the small aerodynamic effects and the small nonlinear friction forces. The correct computation of these two small effects is crucial to determine the final amplitude of the flutter vibration, which basically results from its balance. In this work, we apply asymptotic techniques to consistently derive, from a bladed-disk model, a reduced order model that gives only the time evolution on the slow modulation, filtering out the fast elastic oscillation. This reduced model is numerically integrated with very low computational cost, and we quantitatively compare its results with those from the bladed-disk model. The analysis of the friction saturation of the flutter instability also allows us to conclude that: (i) the final states are always nonlinearly saturated TW; (ii) depending on the initial conditions, there are several different nonlinear TWs that can end up being a final state; and (iii) the possible final TWs are only the more flutter prone ones.
Experimental Investigation of Tip Clearance Flow in a Transonic Compressor With and Without Plasma Actuators
Authors: Saddoughi S. , Bennett G. , Boespflug M. , Puterbaugh S. L. , Wadia A. R.
Published: August 2014

Blade tip losses represent a major performance penalty in low aspect ratio transonic compressors. This paper reports on the experimental evaluation of the impact of tip clearance with and without plasma actuator flow control on performance of an U.S. Air Force-designed low aspect ratio, high radius ratio single-stage transonic compressor rig. The detailed stage performance measurements without flow control at three clearance levels, classified as small, medium, and large, are presented. At design-speed, increasing the clearance from small to medium resulted in a stage peak efficiency drop of almost six points with another four point drop in efficiency with the large clearance (LC). Comparison of the speed lines at high-speed show significantly lower pressure rise with increasing tip clearance, the compressor losing 8% stall margin (SM) with medium clearance (MC) and an additional 1% with the LC. Comparison of the stage exit radial profiles of total pressure and adiabatic efficiency at both part-speed and design-speed and with throttling are presented. Tip clearance flow-control was investigated using dielectric barrier discharge (DBD) type plasma actuators. The plasma actuators were placed on the casing wall upstream of the rotor leading edge and the compressor mapped from part-speed to high-speed at three clearances with both axial and skewed configurations at six different frequency levels. The plasma actuators did not impact steady state performance. A maximum SM improvement of 4% was recorded in this test series. The LC configuration benefited the most with the plasma actuators. Increased voltage provided more SM improvement. Plasma actuator power requirements were almost halved going from continuous operation to pulsed plasma. Most of the improvement with the plasma actuators is attributed to the reduction in unsteadiness of the tip clearance vortex near-stall resulting in additional reduction in flow prior to stall.
Modeling and Simulation of the Dynamic Operating Behavior of a High Solar Share Gas Turbine System
Authors: Felsmann Christian , Gampe Uwe , Heide Stephan , Freimark Manfred
Published: August 2014

Solar gas turbine (GT) systems provide the opportunity to utilize solar heat at a much higher temperature than solar thermal power plants based on steam turbine cycles. Therefore, GT technology has the potential to improve the efficiency of future solar thermal power plants. Nevertheless, to achieve mature technology for commercial application, further development steps are required. Knowledge of the operational behavior of the solar GT system is the basis for the development of the systems control architecture and safety concept. The paper addresses dynamic simulation of high solar share GT systems, which are characterized by primary input of solar heat to the GT. To analyze the dynamic operating behavior, a model with parallel arrangement of the combustion chamber and the solar receiver was set up. By using the heaviside step function, the system dynamics were translated into transfer functions which are used to develop controllers for the particular system configuration. Two operating conditions were simulated to test the controller performance. The first case is the slow increase and decrease of solar heat flow, as part of a regular operation. The second case is an assumed rapid change of solar heat flow, which can be caused by clouds. For all cases, time plots of critical system parameters are shown and analyzed. The simulation results show much more complex system behavior compared to conventional GT systems. This is due to the additional solar heat source, large volumes, and stored thermal energy as well as the time delay of energy transportation caused by the piping system.
About Puncture Testing Applied for Mechanical Characterization of Fetal Membranes
Authors: Bürzle Wilfried , Mazza Edoardo , Moore John J.
Published: August 2014

Puncture testing has been applied in several studies for the mechanical characterization of human fetal membrane (FM) tissue, and significant knowledge has been gained from these investigations. When comparing results of mechanical testing (puncture, inflation, and uniaxial tension), we have observed discrepancies in the rupture sequence of FM tissue and significant differences in the deformation behavior. This study was undertaken to clarify these discrepancies. Puncture experiments on FM samples were performed to reproduce previous findings, and numerical simulations were carried out to rationalize particular aspects of membrane failure. The results demonstrate that both rupture sequence and resistance to deformation depend on the samples' fixation. Soft fixation leads to slippage in the clamping, which reduces mechanical loading of the amnion layer and results in chorion rupturing first. Conversely, the stiffer, stronger, and less extensible amnion layer fails first if tight fixation is used. The results provide a novel insight into the interpretation of ex vivo testing as well as in vivo membrane rupture.
Vehicle Parameter Identification for Vertical Dynamics
Authors: Cui Yan , Kurfess Thomas R.
Published: August 2014

In this paper, a nonlinear full car model considering the nonlinear and hysteretic characteristics of the shock absorber is developed. An approach to integrate the hybrid shock absorber model into the vehicle model using system identification techniques is then presented. To validate the approach, parameter identification of the nominal linear full car model and parameter identification of the full car model with nonlinear/hysteresis shock absorber force input are compared. The target vehicle is tested on an MTS Systems Corporation tire-coupled 4-post road simulator and the experimental data validate the system identification methods proposed in this paper.
Vibration Characteristics of Metamaterial Beams With Periodic Local Resonances
Authors: Nouh M. , Aldraihem O. , Baz A.
Published: August 2014

Vibration characteristics of metamaterial beams manufactured of assemblies of periodic cells with built-in local resonances are presented. Each cell consists of a base structure provided with cavities filled by a viscoelastic membrane that supports a small mass to form a source of local resonance. This class of metamaterial structures exhibits unique band gap behavior extending to very low-frequency ranges. A finite element model (FEM) is developed to predict the modal, frequency response, and band gap characteristics of different configurations of the metamaterial beams. The model is exercised to demonstrate the band gap and mechanical filtering capabilities of this class of metamaterial beams. The predictions of the FEM are validated experimentally when the beams are subjected to excitations ranging between 10 and 5000 Hz. It is observed that there is excellent agreement between the theoretical predictions and the experimental results for plain beams, beams with cavities, and beams with cavities provided with local resonant sources. The obtained results emphasize the potential of the metamaterial beams for providing significant vibration attenuation and exhibiting band gaps extending to low frequencies. Such characteristics indicate that metamaterial beams are more effective in attenuating and filtering low-frequency structural vibrations than plain periodic beams of similar size and weight.
Numerical Local Time Stepping Solutions for Transient Statistical Energy Analysis
Authors: Guasch Oriol , García Carlos
Published: August 2014

Subsystem energies evolve in transient statistical energy analysis (TSEA) according to a linear system of ordinary differential equations (ODEs), which is usually numerically solved by means of the forward Euler finite difference scheme. Stability requirements pose limits on the maximum time step size to be used. However, it has been recently pointed out that one should also consider a minimum time step limit, if time independent loss factors are to be assumed. This limit is based on the subsystem internal time scales, which rely on their characteristic mean free paths and group velocities. In some cases, these maximum and minimum limits become incompatible, leading to a blow up of the forward Euler solution. It is proposed to partially mitigate this problem by resorting to a local time-stepping finite difference strategy. Subsystems are grouped into sets characterized by different time step sizes and evolve according to them.
Simulation Model of a Passive Decay Heat Removal System for Lead-Cooled Fast Reactors
Authors: Damiani Lorenzo , Prato Alessandro Pini
Published: August 2014

The generation IV lead cooled fast reactors are of particular interest for the Italian research: several influential companies (Ansaldo Nucleare, ENEA) are involved in these important European R&D projects. At present, one significant European project in progress is lead cooled European advanced demonstrator reactor (LEADER) which includes, among its goals, the construction of a lead-cooled fast reactor demonstrator, advanced lead fast reactor European demonstrator (ALFRED). The demonstrator has to include technical solutions that simplify the construction phase and assure full safety in operation; according to the latest guidelines, ALFRED final configuration will be characterized by a secondary loop providing bayonet-tube steam generators. The authors have addressed the issue of bayonet-tube steam generators proposing the external boiling bayonet steam generator (EBBSG) system, in which the reaction heat is extracted from the lead by means of coolant under vapor phase. This is possible thanks to an external feed-water boiling, based on the known Loeffler scheme, coupled to the bayonet tube concept. In the present paper, the authors propose a decay heat removal (DHR) system to match the EBBSG scheme. The DHR system is fully passive, exploiting natural circulation phenomena. The performance of the proposed DHR system is investigated through a Matlab-Simulink model. The results are satisfactory since, according to the simulations, the proposed DHR system is able to keep the primary coolant temperature within a safety range for a sufficient time, avoiding the lead freezing or over-heating.
Evaluating tantalum oxide stoichiometry and oxidation states for optimal memristor performance
Authors: Brumbach Michael T. , Mickel Patrick R. , Lohn Andrew J. , Mirabal Alex J. , Kalan Michael A. , Stevens James E. , Marinella Matthew J.
Published: August 2014

Tantalum oxide has shown promising electrical switching characteristics for memristor devices. Consequently, a number of reports have investigated the electrical behavior of TaOx thin films. Some effort has been made to characterize the composition of the TaOx films and it is known that there must be an optimal stoichiometry of TaOx where forming and switching behavior are optimized. However, many previous reports lack details on the methodology used for identifying the chemistry of the films. X-ray photoelectron spectroscopy has been the most commonly used technique; however, peak fitting routines vary widely among reports and a native surface oxide of Ta2O5 often confounds the analysis. In this report a series of large area TaOx films were deposited via sputtering with controlled O2 partial pressures in the sputtering gas, resulting in tunable oxide compositions. Spectra from numerous samples from each wafer spanning a range of oxide stoichiometries were used to develop a highly constrained peak fitting routine. This procedure allowed for the composition of the TaOx films to be identified with greater detail than elemental ratios alone. Additionally, the peak fitting routine was used to evaluate uniformity of deposition across individual wafers. The appearance of a greater contribution of Ta4+ oxidation states in the oxygen starved films are believed to relate to films with optimal forming characteristics.