84 research outputs found

    Atypical clinical presentation and long-term survival in a patient with optic nerve medulloepithelioma: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Medulloepithelioma is a rare congenital tumor of the primitive medullary neuroepithelium. A significant proportion of patients with medulloepithelioma arising from the optic nerve die from intracranial spread or cerebral metastasis. Because it has no known distinct clinical features and because of its low frequency, this tumor presents within the first two to six years of life and is usually misdiagnosed clinically as a different type of optic nerve tumor. Here, we describe a new and atypical case of medulloepithelioma of the optic nerve in a 12-year-old boy. To the best of our knowledge, he is the oldest reported patient to present with this disease and, now as an adult, has the longest documented period of disease-free survival.</p> <p>Case presentation</p> <p>A 12-year-old Caucasian boy with headache and unilateral amaurosis was referred for a presumed optic nerve glioma to our hospital. A computed tomography scan showed optic nerve enlargement, and fundoscopy showed a whitish mass at the optic disc. Our patient had been followed at his local hospital for four years for an 'optic disc cyst' with no change or progression. He experienced mild progressive visual impairment during that period. He was admitted for resection, and a histopathological analysis revealed a medulloepithelioma of the optic nerve. Supplemental orbital radiotherapy was performed. He remained disease-free for 25 years.</p> <p>Conclusions</p> <p>Medulloepithelioma of the optic nerve can clinically mimic more common pediatric tumors, such as optic glioma, meningioma, or retinoblastoma. Thus, medulloepithelioma should be included in the differential diagnoses of pediatric optic nerve lesions. Fundoscopy in these patients may provide relevant information for diagnosis. Anterior optic nerve medulloepitheliomas may behave differently from and have a better prognosis than medulloepitheliomas that have a more posterior location. Our case report illustrates that long-term survival can be achieved in patients with this malignant tumor.</p

    Terahertz metamaterials on flexible polypropylene substrate

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    The final publication is available at Springer via http://dx.doi.org/10.1007/s11468-014-9724-1In this work, we present a metamaterial working at terahertz frequencies made over a flexible polypropylene sub-strate. The experimental measurements, in accordance with the numerical calculations, show the metamaterial reliance on the impinging electric field polarization. The structure s symmetry yields purely electrical resonant responses eliminating bianisotropy effects. The widely used bendable polypropylene polymer may promote the insertion of metamaterial-based structures with special electromagnetic response in a number of objects of our daily lives such as textiles, automotive components, and sensingThis work was supported by the Spanish MICINN under contracts CONSOLIDER EMET CSD2008-00066 and TEC2011-28664-C02-02 and by the Universitat Politecnica de Valencia under the program INNOVA 2011.Ortuño Molinero, R.; GarcĂ­a Meca, C.; MartĂ­nez Abietar, AJ. (2014). Terahertz metamaterials on flexible polypropylene substrate. Plasmonics. 9(5):1143-1147. https://doi.org/10.1007/s11468-014-9724-1S1143114795Smith DR, Padilla WJ, Vier DC, Nemat-Nasser SC, Schultz S (2000) Composite medium with simultaneously negative permeability and permittivity. Phys Rev Lett 84:4184–4187Pendry JB (2000) Negative refraction makes a perfect lens. Phys Rev Lett 85:3966–3969Zhang X, Liu Z (2008) Superlenses to overcome the diffraction limit. Nat Mater 7:435–441Pendry JB, Schurig D, Smith DR (2006) Controlling electromagnetic fields. Science 312:1780–1782Schurig D, Mock JJ, Justice BJ, Cummer SA, Pendry JB, Starr AF, Smith DR (2006) Metamaterial electromagnetic cloak at microwave frequencies. Science 314:977–980RodrĂ­guez-CantĂł PJ, MartĂ­nez-Marco M, RodrĂ­guez-Fortuño FJ, TomĂĄs-Navarro B, Ortuño R, PeransĂ­-Llopis S, MartĂ­nez A (2011) Demonstration of near infrared gas sensing using gold nanodisks on functionalized silicon. Opt Express 19:7664–7672RodrĂ­guez-Fortuño FJ, MartĂ­nez-Marco M, TomĂĄs-Navarro B, Ortuño R, MartĂ­ J, MartĂ­nez A, RodrĂ­guez-CantĂł PJ (2011) Highly-sensitive chemical detection in the infrared regime using plasmonic gold nanocrosses. Appl Phys Lett 98:133118O’Hara FJ, Singh R, Brener I, Smirnova E, Han J, Taylor AJ, Zhang W (2008) Thin-film sensing with planar terahertz metamaterials: sensitivity and limitations. Opt Express 16:1786–1795Tao H, Landy NI, Bingham CM, Zhang X, Averitt RD, Padilla WJ (2008) A metamaterial absorber for the terahertz regime: design, fabrication and characterization. Opt Express 16:7181–7188Iwaszczuk K, Strikwerda AC, Fan K, Zhang X, Averitt RD, Jepsen PU (2012) Flexible metamaterial absorbers for stealth applications at terahertz frequencies. Opt Express 20:635–643Tao H, Bingham CM, Strikwerda AC, Pilon D, Shrekenhamer D, Landy NI, Fan K, Zhang X, Padilla WJ, Averitt RD (2008) Highly flexible wide angle of incidence terahertz metamaterial absorber: design, fabrication, and characterization. Phys Rev B 78:241103(R)Tao H, Bingham CM, Pilon D, Fan K, Strikwerda AC, Shrekenhamer D, Padilla WJ, Zhang X, Averitt RD (2010) A dual band terahertz metamaterial absorber. J Phys D: Appl Phys 43:225102Padilla WJ, Taylor AJ, Highstrete C, Lee M, Averitt RD (2006) Dynamical electric and magnetic metamaterial response at terahertz frequencies. Phys Rev Lett 96:107401Chen HT, Padilla WJ, Zide JMO, Gossard AC, Taylor AJ, Averitt RD (2006) Active terahertz metamaterial devices. Nature 444:597–600Chen HT, O’Hara FJ, Azad AK, Taylor AJ, Averitt RD, Shrekenhamer DB, Padilla WJ (2008) Experimental demonstration of frequency-agile terahertz metamaterials. Nature Photon 2:295–298Chen HT, Padilla WJ, Zide JMO, Bank SR, Gossard AC, Taylor AJ, Averitt RD (2007) Ultrafast optical switching of terahertz metamaterials fabricated on ErAs/GaAs nanoisland superlattices. Opt Lett 32:1620–1622Chen HT, Palit S, Tyler T, Bingham CM, Zide JMO, O’Hara FJ, Smith DR, Gossard AC, Averitt RD, Padilla WJ, Jokerst NM, Taylor AJ (2008) Hybrid metamaterials enable fast electrical modulation of freely propagating terahertz waves. Appl Phys Lett 93:091117Chen HT, Padilla WJ, Cich MJ, Azad AK, Averitt RD, Taylor AJ (2009) A metamaterial solid-state terahertz phase modulator. Nat Photon 3:148Driscoll T, Andreev GO, Basov DN, Palit S, Cho SY, Jokerst NM, Smith DR (2007) Tuned permeability in terahertz split-ring resonators for devices and sensors. Appl Phys Lett 91:062511Debus C, Bolivar PH (2007) Frequency selective surfaces for high sensitivity terahertz sensing. Appl Phys Lett 91:184102Al-Naib IAI, Jansen C, Koch M (2008) Thin-film sensing with planar asymmetric metamaterial resonators. Appl Phys Lett 93:083507Leonhardt U, Philbin TG (2010) Geometry and light: the science of invisibility. Dover, MineolaDi Falco A, Ploschner M, Krauss TF (2010) Flexible metamaterials at visible wavelengths. New J Phys 12:113006Tao H, Strikwerda AC, Fan K, Bingham CM, Padilla WJ, Zhang X, Averitt RD (2008) Terahertz metamaterials on free-standing highly-flexible polyimide substrates. Appl Phys 41:232004Tao H, Amsden JJ, Strikwerda AC, Fan K, Kaplan DL, Zhang X, Averitt RD, Omenetto FJ (2010) Metamaterial silk composites at terahertz frequencies. Adv Mater 22:3527–3531Chen ZC, Han NR, Pan ZY, Gong YD, Chong TC, Hong MH (2011) Tunable resonance enhancement of multi-layer terahertz metamaterials fabricated by parallel laser micro-lens array lithography on flexible substrates. Opt Mat Express 1:151–157Miyamaru F, Takeda MW, Taima K (2009) Characterization of terahertz metamaterials fabricated on flexible plastic films: toward fabrication of bulk metamaterials in terahertz region. Appl Phys Express 2:042001Peralta XG, Wanke MC, Arrington CL, Williams JD, Brener I, Strikwerda A, Averitt RD, Padilla WJ, Smirnova W, Taylor AJ, O’Hara FJ (2009) Large-area metamaterials on thin membranes for multilayer and curved applications at terahertz and higher frequencies. Appl Phys Lett 94:161113Choi M, Lee SH, Kim Y, Kang SB, Shin J, Kwak MH, Kang KY, Lee YH, Park N, Min B (2011) A terahertz metamaterial with unnaturally high refractive index. Nature 470:369–373Han NR, Chen ZC, Lim CS, Ng B, Hong MH (2011) Broadband multi-layer terahertz metamaterials fabrication and characterization on flexible substrates. Opt Express 19:6990–6998Aznabet M, Navarro-Cia N, Kuznetsov SA, Gelfand AV, Fedorinina NI, Goncharov YG, Beruete M, Mrabet OE, Sorolla M (2008) Polypropylene-substrate-based SRR- and CSRR- metasurfaces for submillimeter waves. Opt Express 16:18312–18319Padilla WJ, Aronsson MT, Highstrete C, Lee M, Taylor AJ, Averitt RD (2007) Electrically resonant terahertz metamaterials: theoretical and experimental investigations. Phys Rev B 75:041102(R)Chen HT, O’Hara FJ, Taylor AJ, Averitt RD, Highstrete C, Lee M, Padilla WJ (2007) Complementary planar terahertz metamaterials. Opt Express 15:1084–1095Pendry JB, Holden AJ, Robbins DJ, Stewart WJ (1999) Magnetism from conductors and enhanced nonlinear phenomena. IEEE Trans Microwave Theory Tech 47:2075–208

    Ethnic minority disparities in progression and mortality of pre-dialysis chronic kidney disease : a systematic scoping review

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    Background: There are a growing number of studies on ethnic differences in progression and mortality for pre-dialysis chronic kidney disease (CKD), but this literature has yet to be synthesised, particularly for studies on mortality. Methods: This scoping review synthesized existing literature on ethnic differences in progression and mortality for adults with pre-dialysis CKD, explored factors contributing to these differences, and identified gaps in the literature. A comprehensive search strategy using search terms for ethnicity and CKD was taken to identify potentially relevant studies. Nine databases were searched from 1992 to June 2017, with an updated search in February 2020. Results: 8059 articles were identified and screened. Fifty-five studies (2 systematic review, 7 non-systematic reviews, and 46 individual studies) were included in this review. Most were US studies and compared African-American/Afro-Caribbean and Caucasian populations, and fewer studies assessed outcomes for Hispanics and Asians. Most studies reported higher risk of CKD progression in Afro-Caribbean/African-Americans, Hispanics, and Asians, lower risk of mortality for Asians, and mixed findings on risk of mortality for Afro-Caribbean/African-Americans and Hispanics, compared to Caucasians. Biological factors such as hypertension, diabetes, and cardiovascular disease contributed to increased risk of progression for ethnic minorities but did not increase risk of mortality in these groups. Conclusions: Higher rates of renal replacement therapy among ethnic minorities may be partly due to increased risk of progression and reduced mortality in these groups. The review identifies gaps in the literature and highlights a need for a more structured approach by researchers that would allow higher confidence in single studies and better harmonization of data across studies to advance our understanding of CKD progression and mortality

    Ectoparasite activity during incubation increases microbial growth on avian eggs

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    We thank EstefanĂ­a LĂłpez for lab work, and TomĂĄs PĂ©rez-Contreras and Emilio Pagani-NĂșñez for facilitating collection of some of the flies used in manipulations. We also thank Ángela MartĂ­nez-GarcĂ­a for help with management of ARISA data and Natalia JuĂĄrez and Deseada Parejo for the pictures of owls and roller clutches, respectively. We appreciate the comments provided by Dr. AdĂšle Mennerat and five anonymous referees on earlier versions of the manuscript.All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.While direct detrimental effects of parasites on hosts are relatively well documented, other more subtle but potentially important effects of parasitism are yet unexplored. Biological activity of ectoparasites, apart from skin injuries and blood-feeding, often results in blood remains, or parasite faeces that accumulate and modify the host environment. In this way, ectoparasite activities and remains may increase nutrient availability that may favour colonization and growth of microorganisms including potential pathogens. Here, by the experimental addition of hematophagous flies (Carnus hemapterus, a common ectoparasite of birds) to nests of spotless starlings Sturnus unicolor during incubation, we explore this possible side effect of parasitism which has rarely, if ever, been investigated. Results show that faeces and blood remains from parasitic flies on spotless starling eggshells at the end of incubation were more abundant in experimental than in control nests. Moreover, eggshell bacterial loads of different groups of cultivable bacteria including potential pathogens, as well as species richness of bacteria in terms of Operational Taxonomic Units (OTUs), were also higher in experimental nests. Finally, we also found evidence of a link between eggshell bacterial loads and increased embryo mortality, which provides indirect support for a bacterial-mediated negative effect of ectoparasitism on host offspring. Trans-shell bacterial infection might be one of the main causes of embryo death and, consequently, this hitherto unnoticed indirect effect of ectoparasitism might be widespread in nature and could affect our understanding of ecology and evolution of host-parasite interactionsFinancial support was provided by Spanish Ministerio de EconomĂ­a y Competitividad and FEDER (CGL2013-48193-C3-1-P, CGL2013-48193-C3-2-P), by JAE programme to DMG and MRR, and by Juan de la Cierva and RamĂłn y Cajal programmes to GT. All procedures were conducted under licence from the Environmental Department of the Regional Government of AndalucĂ­a, Spain (reference SGYB/FOA/AFR)

    Natural Variation in an ABC Transporter Gene Associated with Seed Size Evolution in Tomato Species

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    Seed size is a key determinant of evolutionary fitness in plants and is a trait that often undergoes tremendous changes during crop domestication. Seed size is most often quantitatively inherited, and it has been shown that Sw4.1 is one of the most significant quantitative trait loci (QTLs) underlying the evolution of seed size in the genus Solanum—especially in species related to the cultivated tomato. Using a combination of genetic, developmental, molecular, and transgenic techniques, we have pinpointed the cause of the Sw4.1 QTL to a gene encoding an ABC transporter gene. This gene exerts its control on seed size, not through the maternal plant, but rather via gene expression in the developing zygote. Phenotypic effects of allelic variation at Sw4.1 are manifested early in seed development at stages corresponding to the rapid deposition of starch and lipids into the endospermic cells. Through synteny, we have identified the Arabidopsis Sw4.1 ortholog. Mutagenesis has revealed that this ortholog is associated with seed length variation and fatty acid deposition in seeds, raising the possibility that the ABC transporter may modulate seed size variation in other species. Transcription studies show that the ABC transporter gene is expressed not only in seeds, but also in other tissues (leaves and roots) and, thus, may perform functions in parts of the plants other than developing seeds. Cloning and characterization of the Sw4.1 QTL gives new insight into how plants change seed during evolution and may open future opportunities for modulating seed size in crop plants for human purposes

    Decision Agriculture

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    In this chapter, the latest developments in the field of decision agriculture are discussed. The practice of management zones in digital agriculture is described for efficient and smart faming. Accordingly, the methodology for delineating management zones is presented. Modeling of decision support systems is explained along with discussion of the issues and challenges in this area. Moreover, the precision agriculture technology is also considered. Moreover, the chapter surveys the state of the decision agriculture technologies in the countries such as Bulgaria, Denmark, France, Israel, Malaysia, Pakistan, United Kingdom, Ukraine, and Sweden. Finally, different field factors such as GPS accuracy and crop growth are also analyzed

    The Hoopoe's Uropygial Gland Hosts a Bacterial Community Influenced by the Living Conditions of the Bird

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    Molecular methods have revealed that symbiotic systems involving bacteria are mostly based on whole bacterial communities. Bacterial diversity in hoopoe uropygial gland secretion is known to be mainly composed of certain strains of enterococci, but this conclusion is based solely on culture-dependent techniques. This study, by using culture-independent techniques (based on the 16S rDNA and the ribosomal intergenic spacer region) shows that the bacterial community in the uropygial gland secretion is more complex than previously thought and its composition is affected by the living conditions of the bird. Besides the known enterococci, the uropygial gland hosts other facultative anaerobic species and several obligated anaerobic species (mostly clostridia). The bacterial assemblage of this community was largely invariable among study individuals, although differences were detected between captive and wild female hoopoes, with some strains showing significantly higher prevalence in wild birds. These results alter previous views on the hoopoe-bacteria symbiosis and open a new window to further explore this system, delving into the possible sources of symbiotic bacteria (e.g. nest environments, digestive tract, winter quarters) or the possible functions of different bacterial groups in different contexts of parasitism or predation of their hoopoe host.This work was supported by the Ministerio de Ciencia y TecnologĂ­a (projects CGL2005-06975/BOSFEDER; CGL2007-61251/BOSFEDER), the Ministerio de Ciencia e InnovaciĂłn (projects CGL2009-14006/BOSFEDER; CGL2010-19233-C03-01/BOSFEDER; CGL2010-19233-C03-03/BOSFEDER), the Ministerio de EconomĂ­a y Competitividad (projects CGL2013-48193-C3-1-P/BOSFEDER; CGL2013-48193-C3-2-P/BOSFEDER), and the Junta de AndalucĂ­a (RNM 345, P09-RNM-4557). SMRR received a grant from the Ministerio de Ciencia e InnovaciĂłn (FPI program, BES-2011-047677)

    ELISA versus PCR for diagnosis of chronic Chagas disease: systematic review and meta-analysis

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    <p>Abstract</p> <p>Background</p> <p>Most current guidelines recommend two serological tests to diagnose chronic Chagas disease. When serological tests are persistently inconclusive, some guidelines recommend molecular tests. The aim of this investigation was to review chronic Chagas disease diagnosis literature and to summarize results of ELISA and PCR performance.</p> <p>Methods</p> <p>A systematic review was conducted searching remote databases (MEDLINE, LILACS, EMBASE, SCOPUS and ISIWeb) and full texts bibliography for relevant abstracts. In addition, manufacturers of commercial tests were contacted. Original investigations were eligible if they estimated sensitivity and specificity, or reliability -or if their calculation was possible - of ELISA or PCR tests, for chronic Chagas disease.</p> <p>Results</p> <p>Heterogeneity was high within each test (ELISA and PCR) and threshold effect was detected only in a particular subgroup. Reference standard blinding partially explained heterogeneity in ELISA studies, and pooled sensitivity and specificity were 97.7% [96.7%-98.5%] and 96.3% [94.6%-97.6%] respectively. Commercial ELISA with recombinant antigens studied in phase three investigations partially explained heterogeneity, and pooled sensitivity and specificity were 99.3% [97.9%-99.9%] and 97.5% [88.5%-99.5%] respectively. ELISA's reliability was seldom studied but was considered acceptable. PCR heterogeneity was not explained, but a threshold effect was detected in three groups created by using guanidine and boiling the sample before DNA extraction. PCR sensitivity is likely to be between 50% and 90%, while its specificity is close to 100%. PCR reliability was never studied.</p> <p>Conclusions</p> <p>Both conventional and recombinant based ELISA give useful information, however there are commercial tests without technical reports and therefore were not included in this review. Physicians need to have access to technical reports to understand if these serological tests are similar to those included in this review and therefore correctly order and interpret test results. Currently, PCR should not be used in clinical practice for chronic Chagas disease diagnosis and there is no PCR test commercially available for this purpose. Tests limitations and directions for future research are discussed.</p
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