1,436 research outputs found
Ternary Nitride Semiconductors in the Rocksalt Crystal Structure
Inorganic nitrides with wurtzite crystal structures are well-known
semiconductors used in optoelectronic devices. In contrast, rocksalt-based
nitrides are known for their metallic and refractory properties. Breaking this
dichotomy, here we report on ternary nitride semiconductors with rocksalt
crystal structures, remarkable optoelectronic properties, and the general
chemical formula MgTMN (TM=Ti, Zr, Hf, Nb). These compounds form
over a broad metal composition range and our experiments show that Mg-rich
compositions are nondegenerate semiconductors with visible-range optical
absorption onsets (1.8-2.1 eV). Lattice parameters are compatible with growth
on a variety of substrates, and epitaxially grown MgZrN exhibits
remarkable electron mobilities approaching 100 cmVs. Ab
initio calculations reveal that these compounds have disorder-tunable optical
properties, large dielectric constants and low carrier effective masses that
are insensitive to disorder. Overall, these experimental and theoretical
results highlight MgTMN rocksalts as a new class of
semiconductor materials with promising properties for optoelectronic
applications
Dez anos de experiência com a Doença de Jorge Lobo no estado do Acre, região amazônica, Brasil
Jorge Lobo's disease is a cutaneous and subcutaneous mycosis that affects patients in the Amazon region. The number of patients is relatively small, but the real situation of the disease as public health problem is not known, because Jorge Lobo's disease is not a notifiable disease. This study aims to report the clinical evolution in patients affected and to determine the prevalence and areas of occurrence of the disease. A retrospective study was carried out based on the analysis of the clinical records, which included a collection of photographs of patients in the Department of Sanitary Dermatology, in Rio Branco, and patients seen in the interior of the state. In a decade, in Rio Branco, 249 cases of the disease were reported, 30 were females and 219 males. Of these patients, 153 had localized lesions, 94 of them were on one ear, 55 had multifocal lesions and 41 had disseminated lesions. The average time between the onset of symptoms and diagnosis was 19 years. The average age at the time of diagnosis was 53 years, and ages ranged from 14 to 96 years.A doença de Jorge Lobo é micose cutânea e subcutânea que afeta pessoas na região Amazônica. O número de pacientes é relativamente pequeno, no entanto, a real prevalência da doença como problema de saúde pública é pouco conhecida. A doença de Jorge Lobo não é de notificação compulsória. Este estudo teve como objetivo determinar a prevalência, as áreas de ocorrência da doença de Jorge Lobo, além de sua evolução clÃnica. Um estudo retrospectivo foi desenvolvido com base na análise de prontuários de pacientes, incluindo documentação fotográfica dos mesmos, que foram atendidos no Departamento de Dermatologia Sanitária em Rio Branco e no interior do Estado. Foram registrados 249 casos em uma década em Rio Branco, 30 mulheres e 219 homens. Do total 153 apresentavam lesões localizadas, 94 lesões em apenas uma orelha, 55 lesões multifocais e 41 lesões disseminadas. A média de tempo entre o inÃcio dos sintomas e o diagnóstico foi de 19 anos. A média de idade no momento do diagnóstico foi de 53 anos, e as idades variaram de 14 a 96 anos
West Nile Virus in California
The spread of WNV in California is tracked
1862-07-05 N. Woods and others recommend George R. Parsons for 2nd Lieutenant
https://digitalmaine.com/cw_me_16th_regiment_corr/1044/thumbnail.jp
Decreased Serum Levels of S-100B Protein Reflect Successful Treatment Effects in a Rabbit Model of Acute Ischemic Stroke
Serum levels of S-100B were investigated as a marker for infarct volume and response to treatment following acute ischemic stroke in rabbits. Following subselective angiography, rabbits (n=31) were embolized by injection of a 3-day-old blood clot (0.6x4.0-mm) into the internal carotid artery. Treatment began 1-hr post-embolization, groups included: Control (n=8, embolization only), tissue plasminogen activator (tPA, n=12, 0.9mg/kg), and perflutren lipid microbubbles with transcranial ultrasound (MB+US, n=11, MB at 0.16mg/kg, US at 1-MHz pulsed-wave, 0.8 W/cm2 for 1-hr). Serum S-100B levels were significantly increased (P<0.01) 24-hours following embolization in control (3.1-fold over baseline) and tPA (2.9-fold) groups, while treatment with MB+US resulted in an attenuated, non-significant (P=0.221) increase (1.6-fold). Twenty-four hour infarct volumes averaged 4.76%±1.16% for controls, 2.25%±0.95% for rabbits treated with tPA (P=0.32 vs. control), and 0.79%±0.99% for rabbits treated with MB+US (P=0.04 vs. control). Twenty-four hour concentrations of S-100B were positively correlated with infarct volume (r=0.59, P=0.0004)
Identification of Burkholderia mallei and Burkholderia pseudomallei adhesins for human respiratory epithelial cells
<p>Abstract</p> <p>Background</p> <p><it>Burkholderia pseudomallei </it>and <it>Burkholderia mallei </it>cause the diseases melioidosis and glanders, respectively. A well-studied aspect of pathogenesis by these closely-related bacteria is their ability to invade and multiply within eukaryotic cells. In contrast, the means by which <it>B. pseudomallei </it>and <it>B. mallei </it>adhere to cells are poorly defined. The purpose of this study was to identify adherence factors expressed by these organisms.</p> <p>Results</p> <p>Comparative sequence analyses identified a gene product in the published genome of <it>B. mallei </it>strain ATCC23344 (locus # BMAA0649) that resembles the well-characterized <it>Yersinia enterocolitica </it>autotransporter adhesin YadA. The gene encoding this <it>B. mallei </it>protein, designated <it>boaA</it>, was expressed in <it>Escherichia coli </it>and shown to significantly increase adherence to human epithelial cell lines, specifically HEp2 (laryngeal cells) and A549 (type II pneumocytes), as well as to cultures of normal human bronchial epithelium (NHBE). Consistent with these findings, disruption of the <it>boaA </it>gene in <it>B. mallei </it>ATCC23344 reduced adherence to all three cell types by ~50%. The genomes of the <it>B. pseudomallei </it>strains K96243 and DD503 were also found to contain <it>boaA </it>and inactivation of the gene in DD503 considerably decreased binding to monolayers of HEp2 and A549 cells and to NHBE cultures.</p> <p>A second YadA-like gene product highly similar to BoaA (65% identity) was identified in the published genomic sequence of <it>B. pseudomallei </it>strain K96243 (locus # BPSL1705). The gene specifying this protein, termed <it>boaB</it>, appears to be <it>B. pseudomallei</it>-specific. Quantitative attachment assays demonstrated that recombinant <it>E. coli </it>expressing BoaB displayed greater binding to A549 pneumocytes, HEp2 cells and NHBE cultures. Moreover, a <it>boaB </it>mutant of <it>B. pseudomallei </it>DD503 showed decreased adherence to these respiratory cells. Additionally, a <it>B. pseudomallei </it>strain lacking expression of both <it>boaA </it>and <it>boaB </it>was impaired in its ability to thrive inside J774A.1 murine macrophages, suggesting a possible role for these proteins in survival within professional phagocytic cells.</p> <p>Conclusions</p> <p>The <it>boaA </it>and <it>boaB </it>genes specify adhesins that mediate adherence to epithelial cells of the human respiratory tract. The <it>boaA </it>gene product is shared by <it>B. pseudomallei </it>and <it>B. mallei </it>whereas BoaB appears to be a <it>B. pseudomallei</it>-specific adherence factor.</p
Decoupling of monsoon activity across the northern and southern Indo-Pacific during the Late Glacial
© The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Quaternary Science Reviews 176 (2017): 101-105, doi:10.1016/j.quascirev.2017.09.014.Recent studies of stalagmites from the Southern Hemisphere tropics of Indonesia
revealed two shifts in monsoon activity not apparent in records from the Northern Hemisphere
sectors of the Austral-Asian monsoon system: an interval of enhanced rainfall at ~19 ka,
immediately prior to Heinrich Stadial 1, and a sharp increase in precipitation at ~9 ka.
Determining whether these events are site-specific or regional is important for understanding the
full range of sensitivities of the Austral-Asian monsoon. We present a discontinuous 40 kyr
carbon isotope record of stalagmites from two caves in the Kimberley region of the north-central
Australian tropics. Heinrich stadials are represented by pronounced negative carbon isotopic
anomalies, indicative of enhanced rainfall associated with a southward shift of the intertropical
convergence zone and consistent with hydroclimatic changes observed across Asia and the Indo-
Pacific. Between 20-8 ka, however, the Kimberley stalagmites, like the Indonesian record, reveal
decoupling of monsoon behavior from Southeast Asia, including the early deglacial wet period
(which we term the Late Glacial Pluvial) and the abrupt strengthening of early Holocene
monsoon rainfall.Funded by grants from the U.S. National Science Foundation Paleo Perspectives on
Climate Change program (AGS-1103413 and AGS-1502917 to RFD) and AGS-1602455 (to
CCU and RFD), the Center for Global and Regional Environmental Research, and Cornell
College (to RFD). CCU acknowledges support from The Investment in Science Fund given
primarily by WHOI Trustee and Corporation Members. Support also received from the
Kimberley Foundation Australia
The seismic attenuation structure of the East Pacific Rise
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1992.Includes bibliographical references (p. 321-337).by William Sam Douglas Wilcock.Ph.D
Reply to Nott: Assessing biases in speleothem records of flood events
This article is published as Denniston, Rhawn F., Gabriele Villarini, Angelique N. Gonzales, Victor J. Polyak, Caroline C. Ummenhofer, Matthew S. Lachniet, Alan D. Wanamaker Jr, William F. Humphreys, David Woods, and John Cugley. "Reply to Nott: Assessing biases in speleothem records of flood events." Proceedings of the National Academy of Sciences of the United States of America 112, no. 34 (2015): E4637. doi: 10.1073/pnas.1513354112. Posted with permission.</p
1862-05-27 N. Woods and others recommend E.W. Atwood for appointment as Lieutenant
https://digitalmaine.com/cw_me_16th_regiment_corr/1025/thumbnail.jp
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