1,930 research outputs found
Relationship between land use and spatial variability of atmospheric brown carbon and black carbon aerosols in Amazonia
The aerosol radiative effect is an important source of uncertainty in estimating the anthropogenic impact of global climate change. One of the main open questions is the role of radiation absorption by aerosols and its relation to land use worldwide, particularly in the Amazon Rainforest. Using AERONET (Aerosol Robotic Network) long-term measurements of aerosol optical depth (AOD) at a wavelength of 500 nm and absorption AOD (AAOD) at wavelengths of 440, 675, and 870 nm, we estimated the fraction and seasonality of the black carbon (BC) and brown carbon (BrC) contributions to absorption at 440 nm. This was conducted at six Amazonian sites, from central Amazon (Manaus and the Amazon Tall Tower Observatory—ATTO) to the deforestation arc (Rio Branco, Cuiabá, Ji-Paraná, and Alta Floresta). In addition, land use and cover data from the MapBiomas collection 6.0 was used to access the land transformation from forest to agricultural areas on each site. The results showed, for the first time, important geographical and seasonal variability in the aerosol optical properties, particularly the BC and BrC contributions. We observed a clear separation between dry and wet seasons, with BrC consistently accounting for an average of approximately 12% of the aerosol AAOD at 440 nm in the deforestation arc. In central Amazon, the contribution of BrC was approximately 25%. A direct relationship between the reduction in forests and the increase in the area dedicated to agriculture was detected. Moreover, places with lower fractions of forest had a smaller fraction of BrC, and regions with higher fractions of agricultural areas presented higher fractions of BC. Therefore, significant changes in AOD and AAOD are likely related to land-use transformations and biomass burning emissions, mainly during the dry season. The effects of land use change could introduce differences in the radiative balance in the different Amazonian regions. The analyses presented in this study allow a better understanding of the role of aerosol emissions from the Amazon Rainforest that could have global impacts
Integrating informatics tools and portable sequencing technology for rapid detection of resistance to anti-tuberculous drugs
BACKGROUND: Mycobacterium tuberculosis resistance to anti-tuberculosis drugs is a major threat to global public health. Whole genome sequencing (WGS) is rapidly gaining traction as a diagnostic tool for clinical tuberculosis settings. To support this informatically, previous work led to the development of the widely used TBProfiler webtool, which predicts resistance to 14 drugs from WGS data. However, for accurate and rapid high throughput of samples in clinical or epidemiological settings, there is a need for a stand-alone tool and the ability to analyse data across multiple WGS platforms, including Oxford Nanopore MinION. RESULTS: We present a new command line version of the TBProfiler webserver, which includes hetero-resistance calling and will facilitate the batch processing of samples. The TBProfiler database has been expanded to incorporate 178 new markers across 16 anti-tuberculosis drugs. The predictive performance of the mutation library has been assessed using > 17,000 clinical isolates with WGS and laboratory-based drug susceptibility testing (DST) data. An integrated MinION analysis pipeline was assessed by performing WGS on 34 replicates across 3 multi-drug resistant isolates with known resistance mutations. TBProfiler accuracy varied by individual drug. Assuming DST as the gold standard, sensitivities for detecting multi-drug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) were 94% (95%CI 93-95%) and 83% (95%CI 79-87%) with specificities of 98% (95%CI 98-99%) and 96% (95%CI 95-97%) respectively. Using MinION data, only one resistance mutation was missed by TBProfiler, involving an insertion in the tlyA gene coding for capreomycin resistance. When compared to alternative platforms (e.g. Mykrobe predictor TB, the CRyPTIC library), TBProfiler demonstrated superior predictive performance across first- and second-line drugs. CONCLUSIONS: The new version of TBProfiler can rapidly and accurately predict anti-TB drug resistance profiles across large numbers of samples with WGS data. The computing architecture allows for the ability to modify the core bioinformatic pipelines and outputs, including the analysis of WGS data sourced from portable technologies. TBProfiler has the potential to be integrated into the point of care and WGS diagnostic environments, including in resource-poor settings
Multicompartment body composition analysis in older adults: a cross-sectional study
Background
During aging, changes occur in the proportions of muscle, fat, and bone. Body composition (BC) alterations have a great impact on health, quality of life, and functional capacity. Several equations to predict BC using anthropometric measurements have been developed from a bi-compartmental (2-C) approach that determines only fat mass (FM) and fat-free mass (FFM). However, these models have several limitations, when considering constant density, progressive bone demineralization, and changes in the hydration of the FFM, as typical changes during senescence. Thus, the main purpose of this study was to propose and validate a new multi-compartmental anthropometric model to predict fat, bone, and musculature components in older adults of both sexes.
Methods
This cross-sectional study included 100 older adults of both sexes. To determine the dependent variables (fat mass [FM], bone mineral content [BMC], and appendicular lean soft tissue [ALST]) whole total and regional dual-energy X-ray absorptiometry (DXA) body scans were performed. Twenty-nine anthropometric measures and sex were appointed as independent variables. Models were developed through multivariate linear regression. Finally, the predicted residual error sum of squares (PRESS) statistic was used to measure the effectiveness of the predicted value for each dependent variable.
Results
An equation was developed to simultaneously predict FM, BMC, and ALST from only four variables: weight, half-arm span (HAS), triceps skinfold (TriSK), and sex. This model showed high coefficients of determination and low estimation errors (FM: R2adj: 0.83 and SEE: 3.16; BMC: R2adj: 0.61 and SEE: 0.30; ALST: R2adj: 0.85 and SEE: 1.65).
Conclusion
The equations provide a reliable, practical, and low-cost instrument to monitor changes in body components during the aging process. The internal cross-validation method PRESS presented sufficient reliability in the model as an inexpensive alternative for clinical field use.info:eu-repo/semantics/publishedVersio
Improved X-ray detection and particle identification with avalanche photodiodes
Avalanche photodiodes are commonly used as detectors for low energy x-rays.
In this work we report on a fitting technique used to account for different
detector responses resulting from photo absorption in the various APD layers.
The use of this technique results in an improvement of the energy resolution at
8.2 keV by up to a factor of 2, and corrects the timing information by up to 25
ns to account for space dependent electron drift time. In addition, this
waveform analysis is used for particle identification, e.g. to distinguish
between x-rays and MeV electrons in our experiment.Comment: 6 pages, 6 figure
Qualidade de azeites de oliva extravirgens produzidos no Brasil.
Diante da demanda crescente de azeites de oliva extravirgem no Brasil, que está entre os dez maiores importadores do mundo, e com a identificação de regiões com condições edafoclimáticas propícias à olivicultura, a produção de azeites de oliva a partir de azeitonas cultivadas no país tem crescido nos últimos anos. Os principais Estados produtores, atualmente, são Rio Grande do Sul, Minas Gerais e São Paulo, onde já existem olivais com produção comercial implantados. A caracterização desses azeites ao longo de safras consecutivas se faz necessária para verificar se o produto brasileiro atende às normas internacionais para o padrão de identidade e qualidade de azeite de oliva. Nesse sentido, azeites de oliva extra virgem produzidos no Brasil, em diferentes locais, nas safras de 2015, 2016 e 2017, foram avaliados quanto ao padrão de qualidade e composição em ácidos graxos. Foram avaliadas 43 amostras obtidas junto aos produtores entre azeites monovarietais (variedades Arbequina, Arbosana, Barnéa, Coratina, Frantoio, Grappolo, Koroneiki, Mazanilla, Mission e Picual) e blends. Os valores de extinção (K270nm), índice de peróxidos e acidez (em ácido oleico) foram, respectivamente, de 0,09-0,21, 4,9-15,4 meq/kg e 0,1-0,6 %. Os conteúdos de ácido oleico (C18:1), linoleico (C18:2) e palmítico (C16:0) nos azeites analisados variaram, respectivamente, de 63,8 a 82,1 %, de 4,1 a 12,3 % e de 8,8 a 17,0 %. O padrão de qualidade, bem como a composição em ácidos graxos de todos os azeites analisados atenderam aos limites estabelecidos para azeite de oliva extra virgem pela legislação brasileira, Codex Alimentarius e pelo regulamento do International Olive Oil Council (IOC).ISBN: 978-972-8936-28-0. I CLBHort. Editores Paulo César Tavares de Melo, António Calado. 1-4 nov. 2017
First isolation of human Leptospira strains, Azores, Portugal.
OBJECTIVES The aim of this study was the first identification of Leptospira isolates from Azorean inpatients. METHODS Whole blood samples from 68 inpatients attending the São Miguel Hospital between 2006 and 2008, with a clinical and epidemiological suspicion of leptospirosis, were inoculated in a transport medium broth at the patient's bedside and further processed using a serial dilution technique prior to culture. At admission, 62 (91%) patients were also analyzed for the presence of leptospiral DNA by a nested PCR and 40 (59%) for specific agglutinins by microscopic agglutination test (MAT). The isolates obtained were first assigned at the serogroup level by both MAT reactivity with hyperimmune rabbit antisera and a PCR-based assay with the single primer iRep1. The species identification was performed by DNA sequencing. The use of monoclonal antibodies allowed intraspecific discrimination at the serovar level. RESULTS Of the 10 (14.7%) human Leptospira isolates, seven were identified as Leptospira interrogans serovar Copenhageni and three as Leptospira borgpetersenii serovar Arborea, which is in agreement with previous data from the Azorean rodent population. CONCLUSIONS This study represents a great step towards the definitive identification of the pathogenic leptospires in Azorean patients and confirms the bacteriological human-rodent connection for the first time.publishersversionpublishe
Perspectives on the Trypanosoma cruzi-host cell receptor interaction
Chagas disease is caused by the parasite Trypanosoma cruzi. The critical initial event is the interaction of the trypomastigote form of the parasite with host receptors. This review highlights recent observations concerning these interactions. Some of the key receptors considered are those for thromboxane, bradykinin, and for the nerve growth factor TrKA. Other important receptors such as galectin-3, thrombospondin, and laminin are also discussed. Investigation into the molecular biology and cell biology of host receptors for T. cruzi may provide novel therapeutic targets
Invasion of Ureaplasma diversum in bovine spermatozoids
<p>Abstract</p> <p>Background</p> <p><it>Ureaplasma diversum </it>has been associated with infertility in cows. In bulls, this mollicute colonizes the prepuce and distal portion of the urethra and may infect sperm cells. The aim of this study is to analyze <it>in vitro </it>interaction of <it>U. diversum </it>isolates and ATCC strains with bovine spermatozoids. The interactions were observed by confocal microscopy and the gentamycin internalization assay.</p> <p>Findings</p> <p><it>U. diversum </it>were able to adhere to and invade spermatozoids after 30 min of infection. The gentamicin resistance assay confirmed the intracellularity and survival of <it>U. diversum </it>in bovine spermatozoids.</p> <p>Conclusions</p> <p>The intracellular nature of bovine ureaplasma identifies a new difficulty to control the reproductive of these animals.</p
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