bluuebunny/crossref_metadata_2025 huggingface dataset:
Prospective longitudinal assessment of sensorineural hearing loss with hyperfractionated radiation therapy alone in patients with average-risk medulloblastoma
Authors: Gupta Tejpal , Mohanty Sarthak , Kannan, Sadhana , Jalali Rakesh
Published: August 2014

Background

To report on sensorineural hearing loss (SNHL) in a cohort of patients treated with hyperfractionated radiation therapy (HFRT) without upfront platinum-based chemotherapy in average-risk medulloblastoma.

Methods

Hearing thresholds were assessed by ear-specific pure-tone audiograms at stimulus frequencies of 0.25, 0.5, 1, 2, 4, and 8 kilohertz. Audiometric assessments were done serially longitudinally at baseline, between 6–12 months after HFRT, and annually thereafter. Pure-tone audiograms were analyzed and graded according to Brock pediatric ototoxicity grading criteria.

Results

Five of 20 (25%) children had communicatively and developmentally significant SNHL (Brock grade 2 or worse) even before starting radiotherapy. On follow-up, new-onset Brock grade 2 or worse ototoxicity was documented in 6 previously normal ears. Eleven patients had preserved hearing in both ears on last audiometric follow-up. Compared with baseline testing, post-HFRT audiometry at 2–3 years showed modest decline in hearing threshold across all frequencies. Age at diagnosis and sex did not significantly impact hearing, while higher cochlear doses trended towards worse hearing outcomes. Tumors that extended more towards one side expectedly showed significant worsening in the ipsilateral ear. There was a differential impact of treatment on the right and left ears with the right ear (and not the left ear) showing significantly worse hearing thresholds in the low-to-intermediate speech frequency range over time.

Conclusion

The use of HFRT for craniospinal irradiation and conformal tumor bed boost without upfront platinum-based chemotherapy in children with average-risk medulloblastoma results in preserved hearing in a large proportion of patients in the audible speech range.
Polymorphic forms of lupane triterpenoid betulonic aldehyde (betulonal)
Authors: Chrobak Elwira , Michalik Ewa , Kusz Joachim , Nowak Maria , Boryczka Stanisław
Published: August 2014

The lupane triterpenoid betulonic aldehyde [also known as betulonal; systematic name: lup-20(29)-en-28-al-3-one, C30H46O2] is a product of betulin oxidation. Crystals were obtained from hexane [form (I)] and dimethyl sulfoxide [form (II)] solutions. Forms (I) and (II) are both orthorhombic. The molecular geometric parameters in the two forms are similar, but the structures are different with respect to the crystal packing. Polymorph (I) contains two independent molecules in the asymmetric unit, while polymorph (II) contains only one molecule, which has a disordered aldehyde group [the disorder ratio is 0.769 (4):0.231 (4)]. In each molecule, the six-membered rings have chair conformations, whereas the cyclopentane ring in each molecule adopts an envelope conformation. All the rings in the lupane nucleus aretrans-fused. The extended structures of both polymorphs are stabilized by weak intermolecular C—H...O and van der Waals interactions. Weak intramolecular C—H...O interactions are also observed.
Evolutionary ecology of microsporidia associated with the invasive ladybird Harmonia axyridis
Authors: Vilcinskas Andreas , Schmidtberg Henrike , Estoup Arnaud , Tayeh Ashraf , Facon Benoit , Vogel Heiko
Published: August 2014

Invasive species are characterized by the rapid growth and spread of their populations after establishing a foothold in new habitats, and there are now many examples of such species negatively affecting biodiversity and the economy. It is unclear why some species can become successful invaders, whereas most (even if closely related) remain noninvasive. We previously proposed a hypothesis that parasites associated with invading species can promote their invasive success if they are harmless toward the invaders but harmful to their competitors and/or predators in the newly colonized habitat. Here we discuss whether microsporidia that have recently been discovered in the invasive ladybird Harmonia axyridis contribute to its invasive success. We show that all H. axyridis beetles sourced from diverse collection sites all over the world carry abundant microsporidia. This suggests that both native and invasive H. axyridis populations are associated with these tolerated parasites, which were likely to have existed in native populations before expansion rather than being acquired in newly colonized areas. We describe the pathogenesis of the microsporidia during different developmental stages of H. axyridis and we address the possibility that the predation of its infected eggs and larvae by competing native ladybird species may lead to their infection and ultimately to their decline. Finally, we discuss our initial hypothesis: microsporidia that are tolerated by an invasive vector insect can be active against susceptible native competitors and/or predator species.
Application of the complete‐data likelihood to estimate juvenile and adult survival for the endangered Hawaiian stilt
Authors: Reed J. M. , Field C. R. , Silbernagle M. D. , Nadig A. , Goebel K. , Dibben‐Young A. , Donaldson P. , Elphick C. S.
Published: August 2014

Applied ecologists routinely use demographic models to predict population trajectories. Survival rates throughout the life cycle, which are required for these models, are often difficult to obtain, especially for long‐lived or mobile species. Detailed information for pre‐adult age classes in particular is often lacking. Using a 20‐year dataset from several hundred individuals, we used Markov chain Monte Carlo methods to fit hierarchical models that describe survival rates for both adult and sub‐adult Hawaiian stilts Himantopus mexicanus knudseni, an endangered island endemic. We constructed the complete‐data likelihood and used data augmentation to estimate missing values and incorporate data that were not collected during formal sampling. Survival estimates were lower and more uncertain during the first 2 months of life compared with the remainder of the first year. The probability of first‐year survival averaged 0.55 (95% credibility interval: 0.07–0.90), but varied considerably among cohorts from different years and islands. Probability of adult annual survival differed little between females (0.79; 0.71–0.86) and males (0.80; 0.72–0.87), but increased as birds aged from 1 to 20 years (0.77–0.85). Our analysis confirms that earlier work, despite being based on few data, provided good point estimates for survival rates. Our new analysis, however, provides the first comprehensive assessment of uncertainty in survival rates and detailed information on the nature of variation in first‐year and adult survival. This information will help inform new demographic models and can be used to guide management actions.
Toll-like receptor 3 stimulation promotes Ro52/TRIM21 synthesis and nuclear redistribution in salivary gland epithelial cells, partially via type I interferon pathway
Authors: Kyriakidis N C , Kapsogeorgou E K , Gourzi V C , Konsta O D , Baltatzis G E , Tzioufas A G
Published: August 2014

Up-regulated expression of Ro52/tripartite motif-containing protein 21 (TRIM21), Ro60/TROVE domain family, member 2 (TROVE2) and lupus LA protein/Sjögren's syndrome antigen B (La/SSB) autoantigens has been described in the salivary gland epithelial cells (SGEC) of patients with Sjögren's syndrome (SS). SGECs, the key regulators of autoimmune SS responses, express high levels of surface functional Toll-like receptor (TLR)-3, whereas Ro52/TRIM21 negatively regulates TLR-3-mediated inflammation. Herein, we investigated the effect of TLR-3-signalling on the expression of Ro52/TRIM21, as well as Ro60/TROVE2 and La/SSB autoantigens, by SGECs. The effect of TLR-3 or TLR-4 stimulation on autoantigen expression was evaluated by polyI:C or lipopolysaccharide (LPS) treatment, respectively, of SGEC lines (10 from SS patients, 12 from non-SS controls) or HeLa cells, followed by analysis of mRNA and protein expression. PolyI:C, but not LPS, resulted in a two-step induction of Ro52/TRIM21 mRNA expression by SGECs, a 12-fold increment at 6 h followed by a 2·5-fold increment at 24–48 h, whereas it induced a late two-fold up-regulation of Ro60/TROVE2 and La/SSB mRNAs at 48 h. Although protein expression levels were not affected significantly, the late up-regulation of Ro52/TRIM21 mRNA was accompanied by protein redistribution, from nucleolar-like pattern to multiple coarse dots spanning throughout the nucleus. These late phenomena were mediated significantly by interferon (IFN)-β production, as attested by cognate secretion and specific inhibition experiments and associated with IFN regulatory factor (IRF)3 degradation. TLR-3-signalling had similar effects on SGECs obtained from SS patients and controls, whereas it did not affect the expression of these autoantigens in HeLa cells. TLR-3 signalling regulates the expression of autoantigens by SGECs, implicating innate immunity pathways in their over-expression in inflamed tissues and possibly in their exposure to the immune system.
Maternal thyrotropin is independently related to Small for Gestational Age neonates at term
Authors: Monen L. , Kuppens S.M. , Hasaart T.H. , Oosterbaan H.P. , Oei S.G. , Wijnen H. , Hutton E.K. , Vader H.L. , Pop V.J.
Published: August 2014

Objective

Small for gestational age (SGA) newborns constitute still a major cause of perinatal morbidity and mortality. Overt thyroid disease is a known cause of preterm birth and low birthweight but in its untreated condition it is rare today. In this study, we investigated the possible relation between maternal thyroid function assessed in euthyroid women at each trimester and the incidence of term born SGA neonates.

Design

A prospective cohort study was performed.

Patients

Thyroid function was assessed at 12, 24 and 36 weeks gestation in 1051 healthy Caucasian women who delivered at ≥37 weeks gestation.

Measurements

One‐way anova was used to compare mean TSH and FT4 levels between women with SGA neonates and controls. Multiple logistic regression analysis was performed to adjust for known risk factors of SGA.

Results

Seventy (6·7%) SGA neonates were identified and they were significantly more often born to women with a TSH ≥ 97·5th at first and third trimester. Multiple logistic regression analysis showed that smoking (OR: 4·4, 95% CI: 2·49–7·64), pre‐eclampsia (OR: 2·8, 95% CI: 1·19–6·78) and TSH ≥ 97·5th percentile (OR 3·3, 95% CI 1·39–7·53) were significantly related to SGA. Maternal FT4 levels and TPO‐Ab status were not associated with SGA offspring.

Conclusions

Our data show that TSH levels in the upper range of the reference interval at different trimesters (3·0–3·29 mIU/l) are independently related to an increased risk of delivering SGA neonates at term.
Local Painting and Deformation of Meshes on the GPU
Authors: Schäfer H. , Keinert B. , Nießner M. , Stamminger M.
Published: August 2014

We present a novel method to adaptively apply modifications to scene data stored in GPU memory. Such modifications may include interactive painting and sculpting operations in an authoring tool, or deformations resulting from collisions between scene objects detected by a physics engine. We only allocate GPU memory for the faces affected by these modifications to store fine‐scale colour or displacement values. This requires dynamic GPU memory management in order to assign and adaptively apply edits to individual faces at runtime. We present such a memory management technique based on a scan‐operation that is efficiently parallelizable. Since our approach runs entirely on the GPU, we avoid costly CPU–GPU memory transfer and eliminate typical bandwidth limitations. This minimizes runtime overhead to under a millisecond and makes our method ideally suited to many real‐time applications such as video games and interactive authoring tools. In addition, our algorithm significantly reduces storage requirements and allows for much higher resolution content compared to traditional global texturing approaches. Our technique can be applied to various mesh representations, including Catmull–Clark subdivision surfaces, as well as standard triangle and quad meshes. In this paper, we demonstrate several scenarios for these mesh types where our algorithm enables adaptive mesh refinement, local surface deformations and interactive on‐mesh painting and sculpting.
Comparative biochemical analysis of the major yolk protein in the sea urchin egg and coelomic fluid
Authors: Dev Shemul , Robinson John J.
Published: August 2014

The major yolk protein (MYP) is localized to the egg and coelomic fluid of the adult sea urchin. While the egg‐localized MYP has been extensively studied, much less is known about the coelomic fluid‐localized protein. Therefore, we have conducted a comparative biochemical analysis of these proteins. Sucrose density gradient ultracentrifugation revealed unique elution profiles for the MYP species present in the egg, 170‐ and 240 kDa, and the coelomic fluid, 180‐ and 250 kDa. Fractionation in polyacrylamide gels revealed that under reducing conditions both species were present in each location. However, in the absence of reducing agent only one species was present in each fraction: 240 kDa in the egg and 250 kDa in the coelomic fluid. In addition, V8 peptide mapping indicated that all four species have very similar primary structures. Circular dichroic spectral analysis and endogenous tryptophan measurements of the purified 170‐ and 180 kDa species revealed distinctive secondary and tertiary structural features with notable differences in their responses to calcium: apparent Kds of 245‐ and 475 μmol/L were measured for the 170‐ and 180 kDa species, respectively. Further analysis revealed that both species have differing calcium requirements for binding to membranes as well as protein‐dependent, membrane‐membrane interaction. We discuss the functional implications arising from the structural differences which exist between the egg and coelomic fluid resident MYPs.
The implication of periodontitis in vascular endothelial dysfunction
Authors: Gurav Abhijit N.
Published: August 2014

Background

Periodontitis is the most common oral infection seen in humans worldwide. It is characterized by gradual destruction of tooth supporting tissues, eventually leading to loss of tooth. The periodontal biofilm associated with periodontitis comprises of gram‐positive and gram‐negative bacteria, instrumental for the initiation and progression of periodontitis. Evidence‐based literature has identified the nature of periodontal infection as a possible causative condition in the inducement of ‘low‐grade systemic inflammation and infection’. The periodontal pathogens exert systemic effects via the haematogenous route.

Aim

The present review provides an insight into the pathophysiology of the endothelial dysfunction with reference to periodontal infection and highlights the association between periodontitis and endothelial dysfunction. Various studies addressing the implication of periodontitis on endothelial dysfunction will be described, with a focus of periodontal treatment on improvement of endothelial function.

Materials and methods

Studies examining the effects of periodontitis on vascular endothelial function were segregated. Studies conducted on both animal and human models were identified using MEDLINE database search with key search terms such as ‘Periodontitis’, ‘vascular endothelium’, ‘endothelial dysfunction’, ‘periodontal bacteria’ and ‘periodontal therapy’. Systematic reviews and meta‐analysis were also screened. Only studies published in English language were considered. The review has been prepared by screening MEDLINE database from 1989 to 2012.

Results and conclusions

Chronic periodontitis results in altered vascular response, increased expression of pro‐inflammatory cytokines and adhesion molecules inducing vascular endothelial dysfunction. Periodontal therapy may ameliorate the perturbed vascular endothelial function.
OPEN ACCESS JOURNALS AND ACADEMICS' BEHAVIOR
Authors: MIGHELI MATTEO , RAMELLO GIOVANNI B.
Published: August 2014

The rising star of scholarly publishing is Open Access (OA). Even some traditional journals now offer this option on author payment, and many full freely accessible journals are now available to scholars, providing relief to research institutions increasingly unable to afford the escalating subscription rates of serials. However, proper recognition of full OA journals by the community remains a major obstacle to overcome if they are to become a viable alternative for scholarly communication. Through a survey, this work investigates economics scholars' attitudes to OA, and attempts to outline the state of practices and norms governing individuals' publication choices.(JELL17, L86, O33)
Supporting dementia patients in hospital environments: health‐related risks, needs and dedicated structures for patient care
Authors: Hermann D. M. , Muck S. , Nehen H.‐G.
Published: August 2014

The diagnostics and treatment of dementia are progressively gaining importance for European neurologists. Our hospital structures are poorly prepared for patients suffering from dementia. As a consequence of cognitive and physical deficits, dementia patients have an increased risk for serious complications and poor outcomes in hospital environments. In this review, the specific needs of dementia patients are outlined, describing how geriatricians, neurologists and psychiatrists may contribute to better patient care, e.g. with consultation or liaison services, geriatric wards, dedicated dementia wards or memory clinics in interaction with nurses, occupational therapists, physiotherapists, speech therapists, psychologists and social workers. Due to their multifaceted needs, dementia patients can most successfully be supported in clinical environments that closely integrate specialized inpatient, outpatient and primary care offers.
Prediction of traditionally utilised wheat dough technological quality parameters from Mixolab values: development and evaluation of regression models
Authors: Mastilović Jasna , Kevrešan Žarko , Torbica Aleksandra , Janić Hajnal Elizabet , Živančev Dragan
Published: August 2014

The research was conducted with the aim to investigate the possibility of Farinograph, Extensograph and Amylograph values prediction with linear and/or multiple Mixolab regression models. In total, 163 flour samples were divided based on Machalanobis distances into three sets: prediction, validation and external sample set. Determination coefficients ranged from 0.145 to 0.640 for linear regression models and from 0.279 to 0.739 for multiple regression models. Internal and external validation of developed regression models was conducted. Testing of developed models resulted in a high share of samples for which predicted values were out of the ranges of method official reproducibility and a high share of samples for which predicted values were out of the quality level range obtained by analytical measurement. It was concluded that it is impossible to develop applicable regression models for prediction of Farinograph, Extensograph and Amylograph parameters on the basis of Mixolab values from standard protocol.
Abiraterone acetate and prednisolone for metastatic castration‐resistant prostate cancer failing androgen deprivation and docetaxel‐based chemotherapy: A phase II bridging study in Korean and Taiwanese patients
Authors: Kwak Cheol , Wu Tony Tong Lin , Lee Hyun Moo , Wu Hsi Chin , Hong Sung Joon , Ou Yen Chuan , Byun Seok Soo , Rhim Hyou Young , Kheoh Thian , Wan Ying , Yeh Howard , Yu Margaret K , Kim Choung Soo
Published: August 2014

Objectives

To evaluate the safety and efficacy of abiraterone acetate and prednisolone in Korean and Taiwanese patients with metastatic castration‐resistant prostate cancer not responding to docetaxel‐based chemotherapy.

Methods

In this single‐arm study, 82 metastatic castration‐resistant prostate cancer patients who failed docetaxel‐based chemotherapy were treated with abiraterone (1000 mg, once daily) and prednisolone (5 mg, twice daily). Patients achieving a prostate‐specific antigen decline ≥50% were considered as responding.

Results

A total of 35 patients (43%) achieved prostate‐specific antigen response (95% confidence interval 32–54). The median time to prostate‐specific antigen progression was 4.7 months (95% confidence interval 3.7–8.3); the median overall survival was 11.8 months. Two (4%) of 50 patients with measurable disease achieved partial response. The median testosterone concentration was in the castration range (1.21 nmol/L) throughout the treatment period. Median dehydroepiandrosterone sulfate decreased from 0.725 μmol/L (baseline) to 0.080 μmol/L (cycle 4). The most common adverse event was bone pain (20%); grade 3/4 adverse event of special interest were hypokalemia (7%), fluid retention and liver function abnormalities (5% each), hypertension (2%), and cardiac disorders (1%).

Conclusions

A combination of abiraterone acetate and prednisolone appears to be a favorable second‐line treatment in Taiwanese and Korean patients with advanced metastatic castration‐resistant prostate cancer after failed docetaxel‐based chemotherapy.
Improved Fracture Behavior of Alumina Microstructural Composites with Highly Textured Compressive Layers
Authors: Chang Yunfei , Bermejo Raul , Messing Gary L.
Published: August 2014

Alumina‐based microstructural composites combining equiaxed and textured layers were fabricated to examine how cracks propagate and the mechanical properties are affected as a function of the residual stress and volume fraction of texture in a multilayer structure. By combining equiaxed and highly textured alumina layers of varying thermal expansion, the embedded textured layers were placed under compressive residual stresses as high as −670 MPa. Composites with a near constant maximum failure stress of up to 300 MPa were shown to be almost independent of the initial defect size as result of the compressive residual stress in the textured layers. An apparent fracture toughness of up to 10.1 MPa·m1/2 was obtained for composites with an equiaxed to textured volume ratio of 7.4:1. The high compressive stress in the textured layers arrested cracks, whereas the weak bonding parallel to the basal surfaces of the textured alumina grains caused cracks to deflect within the textured layers. The coupling of these two mechanisms resulted in crack arrest and a maximum work of fracture of ~1200 J/m2 or almost 50 times higher than equiaxed alumina. We believe that embedding textured layers having compressive stresses below the surface of multilayer composites represent an important strategy for designing flaw‐tolerant materials with pronounced crack growth resistance and a high work of fracture.
Genetic evaluation of calf and heifer survival in Iranian Holstein cattle using linear and threshold models
Authors: Forutan M. , Ansari Mahyari S. , Sargolzaei M.
Published: August 2014

Calf and heifer survival are important traits in dairy cattle affecting profitability. This study was carried out to estimate genetic parameters of survival traits in female calves at different age periods, until nearly the first calving. Records of 49 583 female calves born during 1998 and 2009 were considered in five age periods as days 1–30, 31–180, 181–365, 366–760 and full period (day 1–760). Genetic components were estimated based on linear and threshold sire models and linear animal models. The models included both fixed effects (month of birth, dam's parity number, calving ease and twin/single) and random effects (herd‐year, genetic effect of sire or animal and residual). Rates of death were 2.21, 3.37, 1.97, 4.14 and 12.4% for the above periods, respectively. Heritability estimates were very low ranging from 0.48 to 3.04, 0.62 to 3.51 and 0.50 to 4.24% for linear sire model, animal model and threshold sire model, respectively. Rank correlations between random effects of sires obtained with linear and threshold sire models and with linear animal and sire models were 0.82–0.95 and 0.61–0.83, respectively. The estimated genetic correlations between the five different periods were moderate and only significant for 31–180 and 181–365 (rg = 0.59), 31–180 and 366–760 (rg = 0.52), and 181–365 and 366–760 (rg = 0.42). The low genetic correlations in current study would suggest that survival at different periods may be affected by the same genes with different expression or by different genes. Even though the additive genetic variations of survival traits were small, it might be possible to improve these traits by traditional or genomic selection.
Russia's Policy on Nuclear Proliferation and National Unification on the Korean Peninsula
Authors: Joo Seung‐Ho
Published: August 2014

As a Northeast Asian power sharing a 17‐Km border with North Korea, Russia has a keen interest in Korean affairs. The future of Korea is of great concern to Russia both because of the Korean peninsula's geostrategic importance and South Korea's alliance relationship with the United States. This article addresses three primary questions: (i) How has Russia's Korea policy evolved over the years? (ii) What position does Russia take on North Korea's nuclear ambitions? and (iii) Will Russia support Korean unification? Russia professes its support for Korean unification. But there are important caveats. Given all the caveats, Russia will be neither active nor positive in supporting Korean unification, especially since it is likely to be achieved on South Korean terms. Will Russia then tolerate a Korean unification, which is likely to follow the German model of the South's absorption of the North? Under the right circumstances, Russia might. In the German case, Mikhail Gorbachev as the Soviet leader and the cooperative relationship between the United States and the Soviet Union were the keys to the smooth sailing to Germany's unification in 1989–1990. As with the German case, the state of US–Russia relations and the type of leader in the Kremlin will prove the most crucial factors in Russia's acceptance or non‐acceptance of a unified Korea. In this article, the author argues that Russia's interests in and policy toward the Korean peninsula have been consistent over the years in two important ways. First, Russia opposes any power's dominance in Korea. Second, Russia prefers a status quo on the Korean peninsula to a Korean unification. The author also argues that Russia will acquiesce to North Korea's status as a de facto nuclear weapons state for lack of a viable alternative.
Necessary stem cell transplantation using myeloablative therapy for myelodysplastic syndrome with progression of genotypic abnormalities and TP53 dysfunction in a young adult
Authors: Sato Yuya , Kurosawa Hidemitsu , Fukushima Keitaro , Okuya Mayuko , Yabe Hiromasa , Arisaka Osamu
Published: August 2014

A 14‐yr‐old male was admitted to our hospital with MDS and the chromosomal abnormality 45,XY,der(5;17)(p10;q10). He rapidly developed karyotype abnormalities, accompanied by the loss of tumor suppressor gene TP53 function. He suffered an early relapse after reduced‐intensity‐conditioning SCT and ultimately required myeloablative therapy before a second SCT. We consider that the analysis of TP53 mutations is essential when planning the treatment of patients with MDS.
A New Series of Fluorescent Indicators for Super Acids
Authors: Shih I‐Chih , Yeh Yu‐Shan , Wu I‐Che , Chen You‐Hua , Shen Jiun‐Yi , Chen Yi‐An , Ho Mei‐Lin , Chou Pi‐Tai
Published: August 2014

The photophysical properties of fluorescent Hammett acidity indicator derived from 3,4,5,6‐tetrahydrobis(pyrido[3,2‐g]indolo)[2,3‐a:3′,2′‐j]acridine (1a), 6‐bis(pyrido[3,2‐g]indol‐2′‐yl)pyridine (1b) and their analogues have been investigated in sulfuric acid solutions by means of absorption, fluorimetry, relaxation dynamics and computational approach. These new indicators undergo a reversible protonation process in the Hammett acidity range of H0 < 0, accompanied by a drastic increase of the bright blue‐green (1a) or yellow (1b) fluorescence intensity upon increasing the acidity. For 1a in H2SO4, the emission yield increases as large as 200 folds from pH = −0.41 to the Hammett acidity range of −5.17, the results of which are rationalized by a much increase of the steric hindrance upon third protonation toward the central pyridinic site, together with their accompanied changes of electronic configuration from charge transfer to a delocalized ππ* character in the lowest lying excited state. The combination of 1a and 1b renders a wide and linear range of H0 measurement from −1.2 to −5.1 detected by highly intensive fluorescence.
Experimental Assessment of Energy Performance and Emissions of a Residential Microcogenerator
Authors: Angrisani Giovanni , Roselli Carlo , Sasso Maurizio , Tzscheutschler Peter
Published: August 2014

Microcogeneration can guarantee sensible primary energy savings and greenhouse gas emissions reductions in the residential sector. In this paper, the results of experimental tests carried out on a microcogenerator (5.5 kW electric power and 14.8 kW thermal power) based on a natural gas fuelled internal combustion engine, integrated with a condensing boiler, have been analyzed. Tests have been performed out at Institute for Energy Economy and Application Technology (IfE) of Technical University of Munich (Germany). The test facility allowed to simulate the thermal energy requirements of a real residential application, represented by a Multi Family House consisting of 10 apartments, and to evaluate the energy flows of the conversion devices in actual operating conditions. Four type days, characteristic of Mediterranean climatic conditions, have been used to define space heating and domestic hot water user’s requirements. Experimental tests have been performed to implement energy and environmental analysis, comparing the system consisting of cogenerator and integration boiler with a reference system. Results showed that the former can achieve a primary energy saving of about 6%, and CO2 equivalent emissions reduction of about 12%. Finally, the algorithm defined by the European Directive on the promotion of high efficiency cogeneration has been implemented; it demonstrated that the primary energy saving is well above the limit value prescribed by the Directive. Therefore the cogeneration plant can access support mechanisms that can help to achieve the economic feasibility of the system, besides energy and environmental benefits.
Flameholding Tendencies of Natural Gas and Hydrogen Flames at Gas Turbine Premixer Conditions
Authors: Sullivan-Lewis Elliot , McDonell Vince
Published: August 2014

Ground-based gas turbines are responsible for generating a significant amount of electric power as well as providing mechanical power for a variety of applications. This is due to their high efficiency, high power density, high reliability, and ability to operate on a wide range of fuels. Due to increasingly stringent air quality requirements, stationary power gas turbines have moved to lean-premixed operation. Lean-premixed operation maintains low combustion temperatures for a given turbine inlet temperature, resulting in low NOx emissions while minimizing emissions of CO and hydrocarbons. In addition, to increase overall cycle efficiency, engines are being operated at higher pressure ratios and/or higher combustor inlet temperatures. Increasing combustor inlet temperatures and pressures in combination with lean-premixed operation leads to increased reactivity of the fuel/air mixture, leading to increased risk of potentially damaging flashback. Curtailing flashback on engines operated on hydrocarbon fuels requires care in design of the premixer. Curtailing flashback becomes more challenging when fuels with reactive components such as hydrogen are considered. Such fuels are gaining interest because they can be generated from both conventional and renewable sources and can be blended with natural gas as a means for storage of renewably generated hydrogen. The two main approaches for coping with flashback are either to design a combustor that is resistant to flashback, or to design one that will not anchor a flame if a flashback occurs. An experiment was constructed to determine the flameholding tendencies of various fuels on typical features found in premixer passage ways (spokes, steps, etc.) at conditions representative of a gas turbine premixer passage way. In the present work, tests were conducted for natural gas and hydrogen between 3 and 9 atm, between 530 K and 650 K, and free stream velocities from 40 to 100 m/s. Features considered in the present study include a spoke in the center of the channel and a step at the wall. The results are used in conjunction with existing blowoff correlations to evaluate flameholding propensity of these physical features over the range of conditions studied. The results illustrate that correlations that collapse data obtained at atmospheric pressure do not capture trends observed for spoke and wall step features at elevated pressure conditions. Also, a notable fuel compositional effect is observed.
Heat Exchanger Design of Direct Evaporative Cooler Based on Outdoor and Indoor Environmental Conditions
Authors: Gilani Neda , Haghighi Poshtiri Amin
Published: August 2014

Performance of a direct evaporative cooler (DEC) was numerically studied at various outdoor and indoor air conditions, with geometric and physical characteristics of it being extracted based on thermal comfort criteria. For this purpose, a mathematical model was utilized based on the equations of mass, momentum, and energy conservation to determine heat and mass transfer characteristics of the system. It is found that the DEC can provide thermal comfort conditions when the outdoor air temperature and relative humidity (RH) are in the range of 27–41 °C and 10–60%, respectively. The findings also revealed that by raising the RH of ambient air, the system will reach the maximum allowed RH faster and hence a smaller heat exchanger can be used when the ambient air has higher RH. Finally, performance of the DEC in a central province of Iran was investigated, and a design guideline was proposed to determine size of the required plate heat exchangers at various operating conditions.
Thermomechanical Modeling of Laser Spot Welded Solar Absorbers
Authors: Spyrou L. A. , Aravas N.
Published: August 2014

A finite element (FE) approach is developed to investigate the laser spot welding (LSW) of flat-plate solar absorbers and the stress and distortion fields that develop after fabrication and during operation. Numerical calculations at two different levels are carried out. At a microscopic scale, the details of a spot weld are analyzed. At a macroscopic level, a global approach is used to simulate the joining of the pipeline to the absorber plate and the “restoration” (flattening) process of the absorber. The simulated welding-induced distortion is compared with experimental measurements. The thermomechanical behavior of a solar absorber under working conditions is also studied and operational stresses and the critical locations for structural failure are reported.
An Enhanced Microstructure-Level Finite Element Machining Model for Carbon Nanotube-Polymer Composites
Authors: Jiang Lingyun , Nath Chandra , Samuel Johnson , Kapoor Shiv G.
Published: August 2014

During the machining of carbon nanotube (CNT)-polymer composites, the interface plays a critical role in the load transfer between polymer and CNT. Therefore, the interface for these composites has to be explicitly considered in the microstructure-level finite element (FE) machining model, so as to better understand their machinability and the interfacial failure mechanisms. In this study, a microstructure-level FE machining model for CNT-polymer composites has been developed by considering the interface as the third phase, in addition to the polymer and the CNT phases. For the interface, two interfacial properties, viz., interfacial strength and fracture energy have been included. To account for variable temperature and strain rate over the deformation zone during machining, temperature and strain rate-dependent mechanical properties for the interface and the polymer material have also been included in the model. It is found that the FE machining model predicts cutting force within 6% of the experimental values at different machining conditions and CNT loadings. The cutting force data reveals that the model can accurately capture the CNT pull-out/protrusion, and the subsequent surface damage. Simulated surface damage characteristics are supported by the surface topographies and roughness values obtained from the machining experiments. The study suggests that the model can be utilized to design the new generation of CNT-polymer composites with specific interfacial properties that minimize the surface/subsurface damage and improve the surface finish.
Analytical Modeling of Solid Material Ignition Under a Radiant Heat Flux Coming From a Spreading Fire Front
Authors: Lamorlette A.
Published: August 2014

This study aims at characterizing ignition of solid targets exposed to spreading fire fronts. In order to model radiant heat fluxes on targets in a realistic way, polynomial heat fluxes are chosen. Analytical solutions for the solid surface temperature evolution regarding different time-varying heat fluxes are discussed for high thermal inertia solids using a mathematical formalism, which allows for the methodology to be extended to the case of low thermal inertia. This formulation also allows calculation of ignition times for more realistic time-dependent fluxes than previous studies on the topic, providing a more general solution to the problem of solid material ignition. Polynomial coefficients are then obtained fitting heat flux coming from absorbing–emitting flames. A characterization of solid material ignition times regarding fire front rate of spread (ROS) is finally performed, showing the need to accurately model heat flux variations in ignition time calculations.
Ignition Probability in a Stratified Turbulent Flow With a Sunken Fire Igniter
Authors: Sforzo Brandon , Kim Jaecheol , Jagoda Jeff , Seitzman Jerry
Published: August 2014

The evolution of a spark kernel ejected by a sunken fire igniter into a turbulent, fuel–air stratified crossflow was studied both experimentally and using a model in a configuration that is similar to the conditions found in turbine engine combustors. This study allows for variations in the transit time of the kernel across a uniform nonflammable region, before entering a second stream containing a flammable fuel–air mixture. High speed schlieren and emission imaging systems are used to visualize the evolution of the kernel and determine the probability of ignition based on measurements over many spark events. Experiments are performed for a range of mean velocities, transit times, inlet (preheat) temperatures, flammable zone equivalence ratios, and nonflammable zone equivalence ratios. In addition to the typical dependence of ignition on the equivalence ratio of the flammable mixture, the results indicate the strong influence of the kernel transit time and the inlet flow temperature on the probability of ignition. The entrainment between the kernel and the surrounding flow appears to be primarily controlled by the kernel ejection-induced flowfield. Reduced-order modeling suggests that the lowering of the kernel temperature associated with entrainment of the nonflammable mixture significantly reduces the ignition probability, and leads to the conclusion that the presence of fuel close to the igniter is necessary to ensure reliable ignition under adverse conditions.
Structural Analysis of a Small H-Darrieus Wind Turbine Using Beam
Models: Development and Assessment
Authors: Bianchini Alessandro , Cangioli Francesco , Papini Susanna , Rindi Andrea , Carnevale Ennio Antonio , Ferrari Lorenzo
Published: August 2014

In the present wind energy research, Darrieus-type vertical axis wind turbines (VAWTs) are increasingly appreciated, especially in small installations. In particular, H-shaped turbines can provide attractive spaces for novel design solutions, aimed at reducing the visual impact of the rotors and then at improving their degree of integration with several installation contexts (e.g., a built environment); moreover, novel small rotors are thought to be able in the near future to make large use also of new and cheaper materials (e.g., plastic or light alloys) which could notably reduce the final cost of the produced energy. As a consequence, the structural analysis of the rotors becomes more and more important: a continuous check between the design solutions needed to maximize the aerodynamic performance of the blades and the structural constraints must be provided. In addition, the requirements of international standards for certification encourage the development of proper numerical tools, possibly with low computational costs for the manufacturers. In this study, the structural analysis of a novel three-helix-bladed Darrieus turbine is presented; the turbine is a real industrial machine almost entirely produced with plastic with a new complex aesthetic design. In detail, a structural modeling based on beam elements has been developed and assessed in comparison to more complex models, as it was thought to provide a notable reduction of the computational cost of the simulations with an acceptable decrease of the accuracy. Moreover, the 1D structural model was exploited to verify the capabilities of a novel software, able to verify the dynamic response of the wind turbine in real functioning, i.e., with mechanical loads and interactions with the wind flow. Benefits and drawbacks of the proposed modeling approach are finally discussed by analyzing both the calculation time and the accuracy of the simulations.
Steady Vortex-Generator Jet Flow Control on a Highly Loaded Transonic Low-Pressure Turbine Cascade: Effects of Compressibility and Roughness
Authors: Bernardini Chiara , Benton Stuart I. , Lee John D. , Bons Jeffrey P. , Chen Jen-Ping , Martelli Francesco
Published: August 2014

A new high-speed linear cascade has been developed for low-pressure turbine (LPT) studies at The Ohio State University. A compressible LPT profile is tested in the facility and its baseline performance at different operating conditions is assessed by means of isentropic Mach number distribution and wake total pressure losses. Active flow control is implemented through a spanwise row of vortex-generator jets (VGJs) located at 60% chord on the suction surface. The purpose of the study is to document the effectiveness of VGJ flow control in high-speed compressible flow. The effect on shock-induced separation is assessed by Mach number distribution, wake loss surveys and shadowgraph. Pressure sensitive paint (PSP) is applied to understand the three dimensional flow and shock pattern developing from the interaction of the skewed jets and the main flow. Data show that with increasing blowing ratio, the losses are first decreased due to separation reduction, but losses connected to compressibility effects become stronger due to increased passage shock strength and jet orifice choking; therefore, the optimum blowing ratio is a tradeoff between these counteracting effects. The effect of added surface roughness on the uncontrolled flow and on flow control behavior is also investigated. At lower Mach number, turbulent separation develops on the rough surface and a different flow control performance is observed. Steady VGJs appear to have control authority even on a turbulent separation but higher blowing ratios are required compared to incompressible flow experiments reported elsewhere. Overall, the results show a high sensitivity of steady VGJs control performance and optimum blowing ratio to compressibility and surface roughness.
A Robust Mixing Plane and Its Application in Three-Dimensional Inverse Design of Transonic Turbine Stages
Authors: Ranjan Ray Saurya , Zangeneh Mehrdad
Published: August 2014

A robust mixing plane method satisfying interface flux conservation, nonreflectivity and retaining interface flow variation; valid at all Mach numbers and applicable for any machine configuration is formulated and implemented in a vertex based finite volume solver for flow analysis and inverse design. The formulation is based on superposing perturbed flow variables derived from the three-dimensional (3D) characteristics obtained along the flow direction on the exchanged mixed out averaged quantities. The method is extended for low speed applications using low Mach number preconditioning. Subsequently, inverse design runs over a single stage transonic low pressure (LP) turbine configuration conducted at a fixed mass flow boundary condition and spanwise loading condition similar to the baseline generates optimized configurations providing performance improvement while achieving prespecified target meridional load distribution.
Stellar origin of the
182
Hf cosmochronometer and the presolar history of solar system matter
Authors: Lugaro Maria , Heger Alexander , Osrin Dean , Goriely Stephane , Zuber Kai , Karakas Amanda I. , Gibson Brad K. , Doherty Carolyn L. , Lattanzio John C. , Ott Ulrich
Published: August 2014

Relocating a heavy-metal factory

We can learn about the solar system's past by measuring heavy radioactive isotopes in meteorites—the extraterrestrial equivalent of carbon dating on Earth. Elements heavier than iron are mainly synthesized in supernovae or asymptotic giant branch (AGB) stars. Knowing exactly which element is produced where, is key to dating the solar system. Lugaro
et al.
found that AGB stars generated more of a nuclide called
182
Hf than previously thought (see the Perspective by Bizzarro). Its abundance indicates that it was produced about 30 million years before the Sun's formation.

Science
, this issue p.
650
; see also p.
620
25-Hydroxycholesterol suppresses interleukin-1–driven inflammation downstream of type I interferon
Authors: Reboldi Andrea , Dang Eric V. , McDonald Jeffrey G. , Liang Guosheng , Russell David W. , Cyster Jason G.
Published: August 2014

Bad cholesterol: Bad for bacteria, too?

Why do viral infections, such as the common cold, leave people more susceptible to bacterial pneumonia? One reason is that type I interferons, secreted proteins that initiate antiviral immune responses, suppress other inflammatory molecules that protect against bacterial infection. Reboldi
et al.
investigated how this suppression occurs on a molecular level in mice. Interferons stimulated expression of a particular enzyme that catalyzes the production of the oxysterol 25-hydroxycholesterol (25-HC). 25-HC inhibits the function of the transcription factor SREBP, which normally drives expression of the gene that encodes interleukin-1, a secreted inflammatory protein with wide-ranging antibacterial functions.

Science
, this issue p.
679
Molecular Typing of Treponema pallidum in the Czech Republic during 2011 to 2013: Increased Prevalence of Identified Genotypes and of Isolates with Macrolide Resistance
Authors: Grillová Linda , Pĕtrošová Helena , Mikalová Lenka , Strnadel Radim , Dastychová Eliška , Kuklová Ivana , Kojanová Martina , Kreidlová Miluše , Vaňousová Daniela , Hercogová Jana , Procházka Přemysl , Zákoucká Hana , Krchňáková Alena , Vašků Vladimír , Šmajs David
Published: August 2014

From January 2011 to December 2013, a total of 262 samples, from 188 patients suspected of having syphilis were tested for the presence of treponemal DNA by PCR amplification of five chromosomal loci, including the
polA
(TP0105),
tmpC
(TP0319), TP0136, TP0548, and 23S rRNA genes. Altogether, 146 samples from 103 patients were PCR positive for treponemal DNA. A set of 81 samples from 62 PCR-positive patients were typeable, and among them, nine different genotypes were identified. Compared to a previous study in the Czech Republic during 2004 to 2010, the number of genotypes detected among syphilis patients in a particular year increased to six in both 2012 and 2013, although they were not the same six. The proportion of macrolide-resistant clinical isolates in this 3-year study was 66.7%.