88 research outputs found

    Luminescence and fine structure correlation in ZnO permeated porous silicon nanocomposites

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    Nanocomposites formed by porous silicon (PS) and zinc oxide (ZnO) have potential for applications in optoelectronic devices. However, understanding the distribution of both materials in the nanocomposite, and especially the fine structure of the synthesized ZnO crystals, is key for future device fabrication. This study focuses on the advanced characterization of a range of PS-ZnO nanocomposites by using photon- and ion-based techniques, such as X-ray absorption spectroscopy (XAS) and elastic backscattering spectroscopy (EBS), respectively. PS substrates formed by the electrochemical etching of p+-type Si are used as host material for the sol-gel nucleation of ZnO nanoparticles. Different properties are induced by annealing in air at temperatures ranging from 200°C to 800°C. Results show that wurtzite ZnO nanoparticles form only at temperatures above 200°C, coexisting with Si quantum dots (QDs) inside a PS matrix. Increasing the annealing temperature leads to structural and distribution changes that affect the electronic and local structure of the samples changing their luminescence. Temperatures around 800°C activate the formation of a new zinc silicate phase and transform PS into an amorphous silicon oxide (SiOx, x ≈ 2) matrix with a noticeably reduced presence of Si QDs. Thus, these changes affect dramatically the emission from these nanocomposites and their potential applicationsFunding through grant MAT2013-46572-C2-1-R from Ministerio de Economía y Competitivida

    Relocation Facilitates the Acquisition of Short Cis-Regulatory Regions that Drive the Expression of Retrogenes during Spermatogenesis in Drosophila

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    Retrogenes are functional processed copies of genes that originate via the retrotranscription of an mRNA intermediate and often exhibit testis-specific expression. Although this expression pattern appears to be favored by selection, the origin of such expression bias remains unexplained. Here, we study the regulation of two young testis-specific Drosophila retrogenes, Dntf-2r and Pros28.1A, using genetic transformation and the enhanced green fluorescent protein reporter gene in Drosophila melanogaster. We show that two different short (< 24 bp) regions upstream of the transcription start sites (TSSs) act as testis-specific regulatory motifs in these genes. The Dntf-2r regulatory region is similar to the known beta 2 tubulin 14-bp testis motif (beta 2-tubulin gene upstream element 1 [beta 2-UE1]). Comparative sequence analyses reveal that this motif was already present before the Dntf-2r insertion and was likely driving the transcription of a noncoding RNA. We also show that the beta 2-UE1 occurs in the regulatory regions of other testis-specific retrogenes, and is functional in either orientation. In contrast, the Pros28.1A testes regulatory region in D. melanogaster appears to be novel. Only Pros28.1B, an older paralog of the Pros28.1 gene family, seems to carry a similar regulatory sequence. It is unclear how the Pros28.1A regulatory region was acquired in D. melanogaster, but it might have evolved de novo from within a region that may have been preprimed for testes expression. We conclude that relocation is critical for the evolutionary origin of male germline-specific cis-regulatory regions of retrogenes because expression depends on either the site of the retrogene insertion or the sequence changes close to the TSS thereafter. As a consequence we infer that positive selection will play a role in the evolution of these regulatory regions and can often act from the moment of the retrocopy insertion.National Institute of General Medical Sciences of the National Institutes of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute of General Medical Sciences (NIGMS) [R01GM071813]; ARRA; UT; NATIONAL INSTITUTE OF GENERAL MEDICAL SCIENCESUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute of General Medical Sciences (NIGMS) [R01GM071813] Funding Source: NIH RePORTERThe authors thank J. Coyne, P. Gibert, F. Lemeunier, M. Long, M.-L. Wu, C.-I. Wu, and the UC San Diego Drosophila Stock Center for providing wild-type Drosophila strains used in this work and Genetic Services, Inc. and the Bloomington Drosophila Stock Center at Indiana University for providing the mutant stocks used in this study. They also thank H. White-Cooper for providing them with her in situ hybridization protocol before publication and for all her advice on its implementation in their lab. They want to thank four anonymous reviewers for comments on this work. M. G. wants to thank Arndt von Haeseler for his support when finalizing the manuscript. This work was supported by, the National Institute of General Medical Sciences of the National Institutes of Health under award number R01GM071813, an ARRA Supplement and UT Arlington startup funds to E. B. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health

    Fracturas de extremidad proximal de cubito en el niño

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    Las fracturas y epifisiolisis proximales de cubito, son lesiones raras y cuando se producen suelen estar mínimamente ó no desplazadas, pudiendo ser tratadas de forma conservadoras. En los casos en que existe desplazamiento significativo, requieren reducción abierta y osteosíntesis. Independientemente del tipo de tratamiento utilizado, el resultado final suele ser satisfactorio. Realizamos un estudio retrospectivo de 13 casos de fractura-epifisiolisis de extremo proximal de cubito, ocurridas durante el periodo 1992-2001. Nuestro objetivo es analizar los resultados obtenidos en el tratamiento de las lesiones y realizar una revisión bibliográfica, teniendo en cuenta los distintos métodos de clasificación, valoración de resultados y las valoraciones descritas para la iniciación de tratamiento quirúrgico de estas lesiones.The epiphysiolisis and proximal lunar fractures in children rare injuries and usually the aren't displaced. In these cases they can be managed nonoperatively. If there's a marked displacement, open reduction and internal fixation is mandatory. The final outcome uses to be successful despite the management; 13 patients with epiphysiolisis or fracture of the proximal ulna between 1992-2001 ere revised. Our aim is to evaluate our outcomes and reviewed the literatur

    Analysis of Exosomal Cargo Provides Accurate Clinical, Histologic and Mutational Information in Non-Small Cell Lung Cancer

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    Lung cancer is a malignant disease with high mortality and poor prognosis, frequently diagnosed at advanced stages. Nowadays, immense progress in treatment has been achieved. However, the present scenario continues to be critical, and a full comprehension of tumor progression mechanisms is required, with exosomes being potentially relevant players. Exosomes are membranous vesicles that contain biological information, which can be transported cell-to-cell and modulate relevant processes in the hallmarks of cancer. The present research aims to characterize the exosomes' cargo and study their role in NSCLC to identify biomarkers. We analyzed exosomes secreted by primary cultures and cell lines, grown in monolayer and tumorsphere formations. Exosomal DNA content showed molecular alterations, whereas RNA high-throughput analysis resulted in a pattern of differentially expressed genes depending on histology. The most significant differences were found in XAGE1B, CABYR, NKX2-1, SEPP1, CAPRIN1, and RIOK3 genes when samples from two independent cohorts of resected NSCLC patients were analyzed. We identified and validated biomarkers for adenocarcinoma and squamous cell carcinoma. Our results could represent a relevant contribution concerning exosomes in clinical practice, allowing for the identification of biomarkers that provide information regarding tumor features, prognosis and clinical behavior of the disease. Keywords: non-small cell lung cancer; liquid biopsy; exosomes; extracellular vesicles; cell cultures; adenocarcinoma; squamous cell carcinoma; biomarker; tumorsphere

    Esophagitis in a High H. pylori Prevalence Area: Severe Disease Is Rare but Concomitant Peptic Ulcer Is Frequent

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    Background: Few data are available on the prevalence of erosive and severe esophagitis in Western countries. Objective: To retrospectively determine the prevalence and the factors predicting erosive esophagitis and severe esophagitis in a large series of endoscopies in Spain. Design: Retrospective observational study. A multivariate analysis was performed to determine variables predicting severe esophagitis. Setting: Databases of 29 Spanish endoscopy units. Patients: Patients submitted to a diagnostic endoscopy during the year 2005. Interventions: Retrospective review of the databases. Main Outcome Measurements: Esophagitis severity (graded according to the Los Angeles classification) and associated endoscopic findings. Results: Esophagitis was observed in 8.7% of the 93,699 endoscopies reviewed. Severe esophagitis (LA grade C or D) accounted for 22.5% of cases of the disease and was found in 1.9% of all endoscopies. Incidences of esophagitis and those of severe esophagitis were 86.2 and 18.7 cases per 100,000 inhabitants per year respectively. Male sex (OR 1.89) and advanced age (OR 4.2 for patients in the fourth age quartile) were the only variables associated with severe esophagitis. Associated peptic ulcer was present in 8.8% of cases. Limitations: Retrospective study, no data on individual proton pump inhibitors use. Conclusions: Severe esophagitis is an infrequent finding in Spain. It occurs predominantly in males and in older individuals. Peptic ulcer disease is frequently associated with erosive esophagitis

    Sex-Biased Expression of MicroRNAs in Schistosoma mansoni

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    Schistosomiasis is an important neglected tropical disease caused by digenean helminth parasites of the genus Schistosoma. Schistosomes are unusual in that they are dioecious and the adult worms live in the blood system. MicroRNAs play crucial roles during gene regulation and are likely to be important in sex differentiation in dioecious species. Here we characterize 112 microRNAs from adult Schistosoma mansoni individuals, including 84 novel microRNA families, and investigate the expression pattern in different sexes. By deep sequencing, we measured the relative expression levels of conserved and newly identified microRNAs between male and female samples. We observed that 13 microRNAs exhibited sex-biased expression, 10 of which are more abundant in females than in males. Sex chromosomes showed a paucity of female-biased genes, as predicted by theoretical evolutionary models. We propose that the recent emergence of separate sexes in Schistosoma had an effect on the chromosomal distribution and evolution of microRNAs, and that microRNAs are likely to participate in the sex differentiation/maintenance process

    Real-Time PCR Improves Helicobacter pylori Detection in Patients with Peptic Ulcer Bleeding

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    Background and aims: Histological and rapid urease tests to detect H. pylori in biopsy specimens obtained during peptic ulcer bleeding episodes (PUB) often produce false-negative results. We aimed to examine whether immunohistochemistry and real-time PCR can improve the sensitivity of these biopsies. Patients and Methods: We selected 52 histology-negative formalin-fixed paraffin-embedded biopsy specimens obtained during PUB episodes. Additional tests showed 10 were true negatives and 42 were false negatives. We also selected 17 histology-positive biopsy specimens obtained during PUB to use as controls. We performed immunohistochemistry staining and real-time PCR for 16S rRNA, ureA, and 23S rRNA for H. pylori genes on all specimens. Results: All controls were positive for H. pylori on all PCR assays and immunohistochemical staining. Regarding the 52 initially negative biopsies, all PCR tests were significantly more sensitive than immunohistochemical staining (p<0.01). Sensitivity and specificity were 55% and 80% for 16S rRNA PCR, 43% and 90% for ureA PCR, 41% and 80% for 23S rRNA PCR, and 7% and 100% for immunohistochemical staining, respectively. Combined analysis of PCR assays for two genes were significantly more sensitive than ureA or 23S rRNA PCR tests alone (p<0.05) and marginally better than 16S rRNA PCR alone. The best combination was 16S rRNA+ureA, with a sensitivity of 64% and a specificity of 80%. Conclusions: Real-time PCR improves the detection of H. pylori infection in histology-negative formalin-fixed paraffin-embedded biopsy samples obtained during PUB episodes. The low reported prevalence of H. pylori in PUB may be due to the failure of conventional tests to detect infection

    High-resolution, large-scale laboratory measurements of a sandy beach and dynamic cobble berm revetment

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    AbstractHigh quality laboratory measurements of nearshore waves and morphology change at, or near prototype-scale are essential to support new understanding of coastal processes and enable the development and validation of predictive models. The DynaRev experiment was completed at the GWK large wave flume over 8 weeks during 2017 to investigate the response of a sandy beach to water level rise and varying wave conditions with and without a dynamic cobble berm revetment, as well as the resilience of the revetment itself. A large array of instrumentation was used throughout the experiment to capture: (1) wave transformation from intermediate water depths to the runup limit at high spatio-temporal resolution, (2) beach profile change including wave-by-wave changes in the swash zone, (3) detailed hydro and morphodynamic measurements around a developing and a translating sandbar.</jats:p
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