5,153 research outputs found
UV Photosensing Characteristics of Nanowire-Based GaN/AlN Superlattices
We have characterized the photodetection capabilities of single GaN nanowires
incorporating 20 periods of AlN/GaN:Ge axial heterostructures enveloped in an
AlN shell. Transmission electron microscopy confirms the absence of an
additional GaN shell around the heterostructures. In the absence of a surface
conduction channel, the incorporation of the heterostructure leads to a
decrease of the dark current and an increase of the photosensitivity. A
significant dispersion in the magnitude of dark currents for different single
nanowires is attributed to the coalescence of nanowires with displaced
nanodisks, reducing the effective length of the heterostructure. A larger
number of active nanodisks and AlN barriers in the current path results in
lower dark current and higher photosensitivity, and improves the sensitivity of
the nanowire to variations in the illumination intensity (improved linearity).
Additionally, we observe a persistence of the photocurrent, which is attributed
to a change of the resistance of the overall structure, particularly the GaN
stem and cap sections. In consequence, the time response is rather independent
of the dark current.Comment: This document is the unedited Author's version of a Submitted Work
that was subsequently accepted for publication in Nano Letters (2016),
copyright (C) American Chemical Society after peer review. To access the
final edited and published work see
http://dx.doi.org/10.1021/acs.nanolett.6b0080
Rickettsia helvetica in Patient with Meningitis, Sweden, 2006
Pathogenicity of Rickettsia helvetica is relatively unknown. We isolated a spotted fever group rickettsial organism from a patient with subacute meningitis. Nucleotide sequences of the 16S rRNA, ompB, and 17kDa genes identified the isolate as R. helvetica. This organism may be associated with serious infections such as central nervous system disorders
Resultados perinatales y del test estresante en embarazos en vías de prolongación y prolongados, Instituto Nacional Materno Perinatal, enero a diciembre del 2016
Describe los resultados perinatales y el resultado del test estresante en embarazos en vías de prolongación y prolongados en el Instituto Nacional Materno Perinatal durante el periodo enero a diciembre de 2016. El estudio es de tipo observacional, descriptivo, retrospectivo y de corte transversal. La muestra está constituida por 250 gestantes con embarazos en vías de prolongación y prolongados que acudieron a la Unidad de Medicina Fetal de Instituto Nacional Materno Perinatal. El análisis de las variables cualitativas se estimó por frecuencias absolutas y porcentajes. La asociación entre las conclusiones del Test estresante, los resultados perinatales con los embarazos en vías de prolongación y prolongados se midió mediante la prueba de Chi cuadrado, el cual se consideró significativo. Encuentra que el 82.5%- 81.8% de las gestantes tuvieron entre 19 a 35 años y el 52,2%-50,0% fueron nulíparas. Entre los resultados perinatales encontramos que en su mayoría tuvieron Apgar al minuto mayor igual de 7 (93.4%-100%), el peso al nacer normal en un 84.6%- 84.8%. La edad gestacional por Capurro mostró asociación significativa. En su mayoría no presentaron lesiones traumáticas (99.1%- 95.5%). Se encontraron dos casos de mortalidad fetal en el grupo de embarazos en vías de prolongación. La cantidad de líquido amniótico es normal en ambos grupos (84.2%-68.2%) así también el líquido claro es mayoritario (69.3%-82.7%); con respecto al diagnóstico de insuficiencia placentaria no es significativo al igual que el sufrimiento fetal agudo, no presentaron circular de cordón un 80.3%-90.9%. Se evidencia una asociación significativa entre los resultados del Test estresante y la edad gestacional. Concluye que los resultados del test estresante se asocia significativamente con los embarazos en vías de prolongación y prolongados.Tesi
Gingival inflammation, enamel defects, and tooth sensitivity in children with amelogenesis imperfecta: a case-control study
Gingival conditions and tooth sensitivity of young patients with amelogenesis imperfecta lack in depth studies. This case-control study aimed to compare (1) the gingival inflammation, the presence of enamel defects, and tooth sensitivity in young patients with and without amelogenesis imperfecta and (2) to investigate if any difference exists between subtypes of amelogenesis imperfecta. Methodology: We compared forty-two participants with amelogenesis imperfecta with forty-two controls matched for age, gender, and the number of examined sites. Based on interview, clinical examination, and intraoral photography, we collected data on periodontal conditions, enamel defects and the presence of tooth sensitivity. Comparison tests were performed to investigate if any difference existed between cases and controls; and among cases, between the different subtypes of amelogenesis imperfecta. We performed a post-hoc analysis for any significant difference observed. Results: We observed more gingival inflammation, enamel defects and tooth sensitivity among cases (all p<0.05). Participants with hypocalcified amelogenesis imperfecta had more gingival inflammation, enamel defects, and tooth sensitivity than patients with the hypoplastic and hypomature subtypes (all p<0.05). After adjustment for dental plaque, gingival inflammation was associated with the presence of amelogenesis imperfecta (OR (95%CI) = 1.14 (1.05; 1.24). p<0.01). Conclusion: Gingival inflammation, enamel defect and tooth sensitivity are more frequently observed among young patients with amelogenesis imperfecta, and more specifically among children with the hypocalcified subtype
Emerging Rickettsioses of the Thai-Myanmar Border1
To investigate the presence of rickettsioses in rural residents of the central Thai-Myanmar border, we tested the blood of 46 patients with fever. Four patients had murine typhus, three patients had scrub typhus, and eight patients had spotted fever group rickettsioses, including the first case of Rickettsia felis infection reported in Asia
Bacterial Zoonoses and Infective Endocarditis, Algeria
Blood culture–negative endocarditis is common in Algeria. We describe the etiology of infective endocarditis in this country. Samples from 110 cases in 108 patients were collected in Algiers. Blood cultures were performed in Algeria. Serologic and molecular analysis of valves was performed in France. Infective endocarditis was classified as definite in 77 cases and possible in 33. Causative agents were detected by blood cultures in 48 cases. All 62 blood culture–negative endocarditis cases were tested by serologic or molecular methods or both. Of these, 34 tested negative and 28 had an etiologic agent identified. A total of 18 infective endocarditis cases were caused by zoonotic and arthropodborne bacteria, including Bartonella quintana (14 cases), Brucella melitensis (2 cases), and Coxiella burnetii (2 cases). Our data underline the high prevalence of infective endocarditis caused by Bartonella quintana in northern Africa and the role of serologic and molecular tools for the diagnosis of blood culture–negative endocarditis
Selective Photoinduced Antibacterial Activity of Amoxicillin-Coated Gold Nanoparticles: From One-Step Synthesis to in Vivo Cytocompatibility
Photoinduced antibacterial gold nanoparticles were developed as an alternative for the treatment of antibiotic-resistant bacteria. Thanks to the amoxicillin coating, they possess high in vivo stability, selectivity for the bacteria wall, a good renal clearance, and are completely nontoxic for eukaryotic cells at the bactericidal concentrations. A simple one-step synthesis of amoxi@AuNP is described at mild temperatures using the antibiotic as both reducing and stabilizing agent. Time-resolved fluorescence microscopy proved these novel nano-photosensitizers, with improved selectivity, are bactericidal but showing excellent biocompatibility toward eukaryotic cells at the same dose (1.5 μg/mL) when co-cultures are analyzed. Their stability in biological media, hemocompatibility, and photo-antibacterial effect against sensitive and antibiotic-resistant Staphylococcus aureus were evaluated in vitro, whereas toxicity, renal clearance, and biodistribution were studied in vivo in male Wistar rats. The use of these nanoparticles to treat antibiotic-resistant infections is promising given their high stability and cytocompatibility
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