185 research outputs found

    Selective large-eddy simulation of hypersonic flows. Procedure to activate the filtering in unresolved regions only (arXiv:1211.1305, submitted to Computer Physics Communications)

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    A new method for the localization of the regions where the turbulent fluctuations are unresolved is applied to the large-eddy simulation (LES) of a compressible turbulent jet with an initial Mach number equal to 5. The localization method used is called selective LES and is based on the exploitation of a scalar probe function f which represents the magnitude of the stretching-tilting term of the vorticity equation normalized with the enstrophy (Tordella et al. 2007). For a fully developed turbulent field of fluctuations, statistical analysis shows that the probability that f is larger than 2 is almost zero, and, for any given threshold, it is larger if the flow is under-resolved. By computing the spatial field of f in each instantaneous realization of the simulation it is possible to locate the regions where the magnitude of the normalized vortical stretching-tilting is anomalously high. The sub-grid model is then introduced into the governing equations in such regions only. The results of the selective LES simulation are compared with those of a standard LES, where the sub-grid terms are used in the whole domain. The comparison is carried out by assuming as reference field a higher resolution Euler simulation of the same jet. It is shown that the selective LES modifies the dynamic properties of the flow to a lesser extent with respect to the classical LES. In particular, the prediction of the enstrophy distribution and of the energy and density spectra are substantially improve

    Waste heat to power conversion by means of thermomagnetic hydrodynamic energy harvester

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    Energy harvesting from extremely low enthalpy sources can play an important role in increasing the sustainability of future energy applications: low temperature differences are common and offer an abundant source, available both in the natural environment and as the result of a many industrial process. This paper presents the first closed-loop thermomagnetic hydrodynamic energy harvester, based on thermomagnetic advection and exploiting a commercial ferrofluid. The lab-scale prototype has a toroidal geometry adopted from the well-known tokamak inertial machines. Peltier modules are used to control the thermal gradient that is harvested and converted directly to electric energy, while permanent magnets trigger the advection. Temperature sensors are installed along the toroidal walls (thermistors) and are placed in contact with the rotating fluid (thermocouples). To extract and ensure the electrical energy output, the structure is wrapped-up with induction coils. Two coil configurations (purely poloidal and mixed poloidal/toroidal windings) are tested, in a heterogeneous two-phase flow from the combination of water carrier and ferrofluid packets, reaching a maximum extracted electrical power per unit of temperature difference of 10.4 ÎŒW/K. This positions the device close to 20% of the ideal Carnot efficiency of a thermal machine working on the same temperature drop. Numerical analysis of the system has been performed developing a Fortranℱ code in a Eulerian framework, using a mixed Fourier-Galerkin/finite difference spatial discretization. The harvester is suitable for producing electricity from running engines, appliances, warm gas exhausts, exothermic processes

    Large-eddy simulation of hypersonic flows. Selective procedure to activate the sub-grid model wherever small scale turbulence is present

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    A new method for the localization of the regions where small scale turbulent fluctuations are present in hypersonic flows is applied to the large-eddy simulation (LES) of a compressible turbulent jet with an initial Mach number equal to 5. The localization method used is called selective LES and is based on the exploitation of a scalar probe function! which represents the magnitude of the stretching tilting term of the vorticity equation normalized with the enstrophy (Tordella et al., 2007) [3]. For a fully developed turbulent field of fluctuations, statistical analysis shows that the probability that f is larger than 2 is almost zero, and, for any given threshold, it is larger if the flow is under-resolved. By computing the spatial field off in each instantaneous realization of the simulation it is possible to locate the regions where the magnitude of the normalized vortical stretching tilting is anomalously high. The sub-grid model is then introduced into the governing equations in such regions only. The results of the selective LES simulation are compared with those of a standard LES, where the sub-grid terms are used in the whole domain, and with those of a standard Euler simulation with the same resolution. The comparison is carried out by assuming as reference field a higher resolution Euler simulation of the same jet. It is shown that the selective LES modifies the dynamic properties of the flow to a lesser extent with respect to the classical LES. In particular, the prediction of the enstrophy, mean velocity and density distributions and of the energy and density spectra are substantially improved

    Clinical and microbiological characteristics of fungal keratitis in the United States, 20012007: A multicenter study

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    Objective: To study the epidemiology, clinical observations, and microbiologic characteristics of fungal keratitis at tertiary eye care centers in the United States. Design: Retrospective multicenter case series. Participants: Fungal keratitis cases presenting to participating tertiary eye care centers. Methods: Charts were reviewed for all fungal keratitis cases confirmed by culture, histology, or confocal microscopy between January 1, 2001, and December 31, 2007, at 11 tertiary clinical sites in the United States. Main Outcome Measures: Frequency of potential predisposing factors and associations between these factors and fungal species. Results: A total of 733 cases of fungal keratitis were identified. Most cases were confirmed by culture from corneal scraping (n = 693) or biopsies (n = 19); 16 cases were diagnosed by microscopic examination of corneal scraping alone; and 5 cases were diagnosed by confocal microscopy alone. Some 268 of 733 cases (37%) were associated with refractive contact lens wear, 180 of 733 cases (25%) were associated with ocular trauma, and 209 of 733 cases (29%) were associated with ocular surface disease. No predisposing factor was identified in 76 cases (10%). Filamentous fungi were identified in 141 of 180 ocular trauma cases (78%) and in 231 of 268 refractive contact lens-associated cases (86%). Yeast was the causative organism in 111 of 209 cases (53%) associated with ocular surface disease. Yeast accounted for few cases of fungal keratitis associated with refractive contact-lens wear (20 cases), therapeutic contact-lens wear (11 cases), or ocular trauma (21 cases). Surgical intervention was undertaken in 26% of cases and was most frequently performed for fungal keratitis associated with ocular surface disease (44%). Surgical intervention was more likely in cases associated with filamentous fungi (P = 0.03). Among contact lens wearers, delay in diagnosis of 2 or more weeks increased the likelihood of surgery (age-adjusted odds ratio = 2.2; 95% confidence interval, 1.24.2). Conclusions: Trauma, contact lens wear, and ocular surface disease predispose patients to developing fungal keratitis. Filamentous fungi are most frequently the causative organism for fungal keratitis associated with trauma or contact lens wear, whereas yeast is most frequently the causative organism in patients with ocular surface disease. Delay in diagnosis increases the likelihood of surgical intervention for contact lens-associated fungal keratitis. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references

    Inheritance analysis and identification of SNP markers associated with ZYMV resistance in Cucurbita pepo

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    [EN] Cucurbit crops are economically important worldwide. One of the most serious threats to cucurbit production is Zucchini yellow mosaic virus (ZYMV). Several resistant accessions were identified in Cucurbita moschata and their resistance was introgressed into Cucurbita pepo. However, the mode of inheritance of ZYMV resistance in C. pepo presents a great challenge to attempts at introgressing resistance into elite germplasm. The main goal of this work was to analyze the inheritance of ZYMV resistance and to identify markers associated with genes conferring resistance. An Illumina GoldenGate assay allowed us to assess polymorphism among nine squash genotypes and to discover six polymorphic single-nucleotide polymorphisms (SNPs) between two near-isogenic lines, "True French" (susceptible to ZYMV) and Accession 381e (resistant to ZYMV). Two F-2 and three BC1 populations obtained from crossing the ZYMV-resistant Accession 381e with two susceptible ones, the zucchini True French and the cocozelle "San Pasquale," were assayed for ZYMV resistance. Molecular analysis revealed an approximately 90% association between SNP1 and resistance, which was confirmed using High Resolution Melt (HRM) and a CAPS marker. Co-segregation up to 72% in populations segregating for resistance was observed for two other SNP markers that could be potentially linked to genes involved in resistance expression. A functional prediction of proteins involved in the resistance response was performed on genome scaffolds containing the three SNPs of interest. Indeed, 16 full-length pathogen recognition genes (PRGs) were identified around the three SNP markers. In particular, we discovered that two nucleotide-binding site leucine-rich repeat (NBS-LRR) protein-encoding genes were located near the SNP1 marker. The investigation of ZYMV resistance in squash populations and the genomic analysis performed in this work could be useful for better directing the introgression of disease resistance into elite C. pepo germplasm.This work was supported by the Ministry of University and Research (GenHORT project).Capuozzo, C.; Formisano, G.; Iovieno, P.; Andolfo, G.; Tomassoli, L.; Barbella, M.; PicĂł Sirvent, MB.... (2017). Inheritance analysis and identification of SNP markers associated with ZYMV resistance in Cucurbita pepo. Molecular Breeding. 37(8). https://doi.org/10.1007/s11032-017-0698-5S378Addinsoft (2007) XLSTAT, Analyse de donnĂ©es et statistique avec MS Excel. Addinsoft, NYAndolfo G, Ercolano MR (2015) Plant innate immunity multicomponent model. Front Plant Sci 6:987Andolfo G, Sanseverino W, Rombauts S et al (2013) Overview of tomato (Solanum lycopersicum) candidate pathogen recognition genes reveals important Solanum R locus dynamics. New Phytol 197:223–237Andolfo G, Ferriello F, Tardella L et al (2014) Tomato genome-wide transcriptional responses to fusarium wilt, and tomato mosaic virus. PLoS One 9:e94963Blanca J, Cañizares J, Roig C, Ziarsolo P, Nuez F, PicĂł B (2011) Transcriptome characterization and high throughput SSRs and SNPs discovery in Cucurbita pepo (Cucurbitaceae). BMC Genomics 12:104Brown RN, Bolanos-Herrera A, Myers JR, Jahn MM (2003) Inheritance of resistance to four cucurbit viruses in Cucurbita moschata. Euphytica 129:253–258Burge CB, Karlin S (1998) Finding the genes in genomic DNA. Curr Opin Struct Biol 8:346–354Cipollini D (2008) Constitutive expression of methyl jasmonate-inducible responses delays reproduction and constrains fitness responses to nutrients in Arabidopsis thaliana. Evol Ecol 24:59–68Cohen R, Hanan A, Paris HS (2003) Single-gene resistance to powdery mildew in zucchini squash (Cucurbita pepo). Euphytica 130:433–441Collum TD, Padmanabhan MS, Hsieh YC, Culver JN (2016) Tobacco mosaic virus-directed reprogramming of auxin/indole acetic acid protein transcriptional responses enhances virus phloem loading. Proc Natl Acad Sci U S A 113:E2740–E2749Desbiez C, Lecoq H (1997) Zucchini yellow mosaic virus. Plant Pathol 46:809–829Ercolano MR, Sanseverino W, Carli P, Ferriello F, Frusciante L (2012) Genetic and genomic approaches for R-gene mediated disease resistance in tomato: retrospects and prospects. Plant Cell Rep 31:973–985Esteras C, GĂłmez P, Monforte AJ, Blanca J, Vicente-DĂłlera N, Roig C, Nuez F, PicĂł B (2012) High-throughput SNP genotyping in Cucurbita pepo for map construction and quantitative trait loci mapping. BMC Genomics 13:80Formisano G, Paris HS, Frusciante L, Ercolano MR (2010) Commercial Cucurbita pepo squash hybrids carrying disease resistance introgressed from Cucurbita moschata have high genetic similarity. Plant Genet Resour 8:198–203Fulton TM, Chunwongse J, Tanksley SD (1995) Microprep protocol for extraction of DNA from tomato and other herbaceous plants. Plant Mol Biol Report 13:207–209Gal-On A (2007) Zucchini yellow mosaic virus: insect transmission and pathogenicity—the tails of two proteins. Mol Plant Pathol 8:139–150Gilbert-Albertini F, Lecoq H, Pitrat M, Nicolet JL (1993) Resistance of Cucurbita moschata to watermelon mosaic virus type 2 and its genetic relation to resistance to zucchini yellow mosaic virus. Euphytica 69:231–237GĂłmez P, RodrĂ­guez-HernĂĄndez AM, Moury B, Aranda MA (2009) Genetic resistance for the sustainable control of plant virus diseases: breeding, mechanisms and durability. Eur J Plant Pathol 125:1–22Gong L, Stift G, Kofler R, Pachner M, Lelley T (2008a) Microsatellites for the genus Cucurbita and an SSR-based genetic linkage map of Cucurbita pepo L. Theor Appl Genet 117:37–48Gong L, Pachner M, Kalai K, Lelley T (2008b) SSR-based genetic linkage map of Cucurbita moschata and its synteny with Cucurbita pepo. Genome 51:878–887Iovieno P, Andolfo G, Schiavulli A, Catalano D, Ricciardi L, Frusciante L et al. (2015) Structure, evolution and functional inference on the MildewLocusO (MLO) gene family in three cultivated Cucurbitaceae. BMC Genomics 16:1112. doi: 10.1186/s12864-015-2325-3Ishibashi K, Kezuka Y, Kobayashi C, Kato M, Inoue T, Nonaka T et al (2014) Structural basis for the recognition–evasion arms race between Tomato mosaic virus and the resistance gene Tm-1. PNAS 111:E3486–E3495Lecoq H, Pitrat M, ClĂ©ment M (1981) Identification et caractĂ©risation d’un potyvirus provoquant la maladie du rabougrissement jaune du melon. Agronomie 1:827–834Lefebvre V, Palloix A (1996) Both epistatic and additive effects of QTLs are involved in polygenic induced resistance to disease: a case study, the interaction pepper—Phytophthora capsici Leonian. Theor Appl Genet 93:503–511Levi A, Thomas CE, Newman M, Zhan X, Xu Y, Wehner TC (2003) Massive preferential segregation and nonrandom assortment of linkage-groups produce quasi-linkage in an F2 mapping population of watermelon. Hortscience 38:782Lisa V, Lecoq H (1984) Zucchini yellow mosaic virus. Descriptions of Plant Viruses, Commonwealth Mycological Institute and Association of Applied Biologists 282Lisa V, Boccardo G, D'Agostino G, Dellavalle G, d’Aquilio M (1981) Characterization of a potyvirus that causes zucchini yellow mosaic. Phytopathology 71:667–672MacQueen A, Bergelson J (2016) Modulation of R-gene expression across environments. J Exp Bot 67:2093–2105Mantel N (1967) The detection of disease clustering and a generalized regression approach. Cancer Res 27:209–220Munger HM, Provvidenti R (1987) Inheritance of resistance to zucchini yellow mosaic virus in Cucurbita moschata. Cucurbit Genet Coop Rep 10:8–81Nameth ST, Dodds JA, Paulus AO, Laemmlen FF (1986) Cucurbit viruses of California: an ever-changing problem. Plant Dis 70:8–12Ott J, Wang J, Leal SM (2015) Genetic linkage analysis in the age of whole-genome sequencing. Nat Rev Genet 16(5):275–284Pachner M, Lelley T (2004) Different genes for resistance to zucchini yellow mosaic virus (ZYMV) in Cucurbita moschata. In: Lebeda A, Paris HS (eds) Progress in cucurbit genetics and breeding research: Proceedings of Cucurbitaceae 2004. Palacky University, Olomouc (Czech Republic), pp 237–243Pachner M, Paris HS, Lelley T (2011) Genes for resistance to zucchini yellow mosaic in tropical pumpkin. J Hered 102:330–335Pachner M, Paris HS, Winkler J, Lelley T (2015) Phenotypic and marker-assisted pyramiding of genes for resistance to zucchini yellow mosaic virus in oilseed pumpkin (Cucurbita pepo). Plant Breed 134:121–128Paris HS (1986) A proposed subspecific classification for Cucurbita pepo. Phytologia 61:133–138Paris HS (2001) Characterization of the Cucurbita pepo collection at the Newe Ya‘ar Research Center, Israel. Plant Genet Resour Newsl 126:41–45Paris HS (2008) Summer squash. In: Prohens J, Nuez F (eds) Handbook of plant breeding, Vegetables I: 351–379Paris HS, Cohen S (2000) Oligogenic inheritance for resistance to zucchini yellow mosaic virus in Cucurbita pepo. Ann Appl Biol 136:209–214Paris HS, Cohen S, Burger Y, Joseph R (1988) Single-gene resistance to zucchini yellow mosaic virus in Cucurbita moschata. Euphytica 37:27–29Peakall PE, Smouse R (2012) GenAlEx 6.5: genetic analysis in Excel. Population genetic software for teaching and research—an update. Bioinformatics 28:2537–2539Sakamoto T, Deguchi M, Brustolini OJ, Santos AA, Silva FF, Fontes EP (2012) The tomato RLK superfamily: phylogeny and functional predictions about the role of the LRRII-RLK subfamily in antiviral defense. BMC Plant Biol 12:229Sanseverino W, Ercolano MR (2012) In silico approach to predict candidate R proteins and to define their domain architecture. BMC Res Notes 5:678Tamura K, Peterson D, Peterson N, Stecher G, Nei M, Kumar S (2011) MEGA5: molecular evolutionary genetics analysis using maximum likelihood, evolutionary distance, and maximum parsimony methods. Mol Biol Evol 28:2731–2739Teare MD, Santibanez Koref MF (2014) Linkage analysis and the study of Mendelian disease in the era of whole exome and genome sequencing. Brief Funct Genomics 13(5):378–383Valkonen JPT, Wiegmann K, HĂ€mĂ€lĂ€inen JH, Marczewski W, Watanabe KN (2008) Evidence for utility of the same PCR-based markers for selection of extreme resistance to Potato virus Y controlled by Rysto of Solanum stoloniferum derived from different sources. Ann Appl Biol 152:121–130Wessel-Beaver L (2005) Cultivar and germplasm release. Release of ‘Soler’ tropical pumpkin. J Agric Univ P R 89:263–266Whitaker TW, Davis GN (1962) Cucurbits: botany, cultivation and utilization. Interscience, New York, pp 105–116Whitaker TW, Robinson RW (1986) Squash breeding. In: Bassett MJ (ed) Breeding vegetable crops. Avi, Westport, pp 209–242Xu Y, Crouch JH (2008) Marker-assisted selection in plant breeding: from publications to practice. Crop Sci 48:391–407Xu R, Zhang S, Huang J, Zheng C (2013) Genome-wide comparative in silico analysis of the RNA helicase gene family in Zea mays and Glycine max: a comparison with Arabidopsis and Oryza sativa. PLoS One 8:e78982Ye G, Smith KF (2008) Marker-assisted gene pyramiding for inbred line development: basic principles and practical guidelines. Int J Plant Breed 2:1–10Zdobnov EM, Apweiler R (2001) InterProScan—an integration platform for the signature-recognition methods in InterPro. Bioinformatics 17:847–848Zraidi A, Stift G, Pachner M, Shojaeiyan A, Gong L, Lelley T (2007) A consensus map for Cucurbita pepo. Mol Breed 20:375–38

    A Probiotic Adjuvant Lactobacillus rhamnosus Enhances Specific Immune Responses after Ocular Mucosal Immunization with Chlamydial Polymorphic Membrane Protein C

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    Recent advances in the development of chlamydia vaccines, using live-attenuated or ultraviolet light-inactivated chlamydia, are paving the way for new possibilities to oppose the societal challenges posed by chlamydia-related diseases, such as blinding trachoma. An effective subunit vaccine would mitigate the risks associated with the use of a whole-cell vaccine. Our rationale for the design of an efficient subunit vaccine against Chlamydia trachomatis (Ct) is based on the membrane proteins involved in the initial Ct-host cell contact and on the route of immunization that mimics the natural infection process (i.e., via the ocular mucosa). The first aim of our study was to characterize the specific conjunctival and vaginal immune responses following eye drop immunization in BALB/c mice, using the N-terminal portion of the Ct serovar E polymorphic membrane protein C (N-PmpC) as the subunit vaccine antigen. Second, we aimed to examine the adjuvant properties of the probiotic Lactobacillus rhamnosus (LB) when formulated with N-PmpC. N-PmpC applied alone stimulated the production of N-PmpC-and Ct serovar B-specific antibodies in serum, tears and vaginal washes, whereas the combination with LB significantly enhanced these responses. The N-PmpC/LB combination initiated a T cell response characterized by an elevated percentage of CD25+ T cells and CD8+ effector T cells, enhanced CD4+ T-helper 1 skewing, and increased regulatory T cell responses. Together, these results show that eye drop vaccination with combined use of N-PmpC and a live probiotic LB stimulates specific cellular and humoral immune responses, not only locally in the conjunctiva but also in the vaginal mucosa, which could be a promising approach in Ct vaccine development

    Combinations of QT-prolonging drugs: towards disentangling pharmacokinetic and pharmaco-dynamic effects in their potentially additive nature.

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    Background: Whether arrhythmia risks will increase if drugs with electrocardiographic (ECG) QT-prolonging properties are combined is generally supposed but not well studied. Based on available evidence, the Arizona Center for Education and Research on Therapeutics (AZCERT) classification defines the risk of QT prolongation for exposure to single drugs. We aimed to investigate how combining AZCERT drug categories impacts QT duration and how relative drug exposure affects the extent of pharmacodynamic drug–drug interactions. Methods: In a cohort of 2558 psychiatric inpatients and outpatients, we modeled whether AZCERT class and number of coprescribed QT-prolonging drugs correlates with observed rate-corrected QT duration (QTc) while also considering age, sex, inpatient status, and other QTc-prolonging risk factors. We concurrently considered administered drug doses and pharmacokinetic interactions modulating drug clearance to calculate individual weights of relative exposure with AZCERT drugs. Because QTc duration is concentration-dependent, we estimated individual drug exposure with these drugs and included this information as weights in weighted regression analyses. Results: Drugs attributing a ‘known’ risk for clinical consequences were associated with the largest QTc prolongations. However, the presence of at least two versus one QTc-prolonging drug yielded nonsignificant prolongations [exposure-weighted parameter estimates with 95% confidence intervals for ‘known’ risk drugs + 0.93 ms (–8.88;10.75)]. Estimates for the ‘conditional’ risk class increased upon refinement with relative drug exposure and coadministration of a ‘known’ risk drug as a further risk factor. Conclusions: These observations indicate that indiscriminate combinations of QTc-prolonging drugs do not necessarily result in additive QTc prolongation and suggest that QT prolongation caused by drug combinations strongly depends on the nature of the combination partners and individual drug exposure. Concurrently, it stresses the value of the AZCERT classification also for the risk prediction of combination therapies with QT-prolonging drugs

    SJS/TEN 2019: From Science to Translation

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    Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) are potentially life-threatening, immune-mediated adverse reactions characterized by widespread erythema, epidermal necrosis, and detachment of skin and mucosa. Efforts to grow and develop functional international collaborations and a multidisciplinary interactive network focusing on SJS/TEN as an uncommon but high burden disease will be necessary to improve efforts in prevention, early diagnosis and improved acute and long-term management. SJS/TEN 2019: From Science to Translation was a 1.5-day scientific program held April 26-27, 2019, in Vancouver, Canada. The meeting successfully engaged clinicians, researchers, and patients and conducted many productive discussions on research and patient care needs

    SJS/TEN 2019: From science to translation.

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    Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) are potentially life-threatening, immune-mediated adverse reactions characterized by widespread erythema, epidermal necrosis, and detachment of skin and mucosa. Efforts to grow and develop functional international collaborations and a multidisciplinary interactive network focusing on SJS/TEN as an uncommon but high burden disease will be necessary to improve efforts in prevention, early diagnosis and improved acute and long-term management. SJS/TEN 2019: From Science to Translation was a 1.5-day scientific program held April 26-27, 2019, in Vancouver, Canada. The meeting successfully engaged clinicians, researchers, and patients and conducted many productive discussions on research and patient care needs
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