217 research outputs found
Antimicrobial properties of membrane-active dodecapeptides derived from MSI-78
Antimicrobial peptides (AMPs) are a class of broad-spectrum antibiotics known by their ability to disrupt bacterial membranes and their low tendency to induce bacterial resistance, arising as excellent candidates to fight bacterial infections. In this study we aimed at designing short 12-mer AMPs, derived from a highly effective and broad spectrum synthetic AMP, MSI-78 (22 residues), by truncating this peptide at the N- and/or C-termini while spanning its entire sequence with 1 amino add (aa) shifts. These designed peptides were evaluated regarding antimicrobial activity against selected gram-positive Staphylococcus strains and the gram-negative Pseudomonas aeruginosa (P. aeruginosa). The short 12-mer peptide CEM1 (GIGMFLKKAKICF) was identified as an excellent candidate to fight P. aeruginosa infections as it displays antimicrobial activity against this strain and selectivity, with negligible toxicity to mammalian cells even at high concentrations. However, in general most of the short 12-mer peptides tested showed a reduction in antimicrobial activity, an effect that was more pronounced for gram-positive Staphylococcus strains. Interestingly, CEM1 and a highly similar peptide differing by only one aa-shift (CEM2: IGKFLKKAKICFG), showed a remarkably contrasting AMP activity. These two peptides were chosen for a more detailed study regarding their mechanism of action, using several biophysical assays and simple membrane models that mimic the mammalian and bacterial lipid composition. We confirmed the correlation between peptide helicity and antimicrobial activity and propose a mechanism of action based on the disruption of the bacterial membrane permeability barrier
Accurate Atmospheric Parameters at Moderate Resolution Using Spectral Indices: Preliminary Application to the MARVELS Survey
Studies of Galactic chemical and dynamical evolution in the solar
neighborhood depend on the availability of precise atmospheric parameters
(Teff, [Fe/H] and log g) for solar-type stars. Many large-scale spectroscopic
surveys operate at low to moderate spectral resolution for efficiency in
observing large samples, which makes the stellar characterization difficult due
to the high degree of blending of spectral features. While most surveys use
spectral synthesis, in this work we employ an alternative method based on
spectral indices to determine the atmospheric parameters of a sample of nearby
FGK dwarfs and subgiants observed by the MARVELS survey at moderate resolving
power (R~12,000). We have developed three codes to automatically normalize the
observed spectra, measure the equivalent widths of the indices and, through the
comparison of those with values calculated with pre-determined calibrations,
derive the atmospheric parameters of the stars. The calibrations were built
using a sample of 309 stars with precise stellar parameters obtained from the
analysis of high-resolution FEROS spectra. A validation test of the method was
conducted with a sample of 30 MARVELS targets that also have reliable
atmospheric parameters from high-resolution spectroscopic analysis. Our
approach was able to recover the parameters within 80 K for Teff, 0.05 dex for
[Fe/H] and 0.15 dex for log g, values that are lower or equal to the typical
external uncertainties found between different high-resolution analyzes. An
additional test was performed with a subsample of 138 stars from the ELODIE
stellar library and the literature atmospheric parameters were recovered within
125 K for Teff, 0.10 dex for [Fe/H] and 0.29 dex for log g. These results show
that the spectral indices are a competitive tool to characterize stars with the
intermediate resolution spectra.Comment: Accepted for publication in AJ. Abstract edited to comply with arXiv
standards regarding the number of character
ANÁLISE NÃO LINEAR DA INFLUÊNCIA DA FISSURAÇÃO NA RESISTÊNCIA AO ARRANCAMENTO DE PINOS EMBUTIDOS EM CONCRETO
Quando conectores de aço com cabeça são solicitados à tração, uma forma de ruptura é ocasionada pelo destacamento de uma região de concreto em torno do conector, em formato de cone. Sabe-se que o aumento do grau de fissuração na região do cone influencia negativamente na resistência do conjunto. Este trabalho apresenta uma modelagem computacional com base em uma série de ensaios experimentais caracterizados pelo arrancamento de conectores de aço embutidos em prismas bi-apoiados de concreto armado. A modelagem visou avaliar a influência do grau de fissuração na resistência do conjunto, onde variou-se a taxa de armadura de flexão de 0,3 até 3,2% entre os modelos, resultando em diferentes graus de fissuração. A análise numérica foi realizada usando o software MIDAS FEA. Foi feito um estudo paramétrico em um dos modelos, para ajustar as propriedades do concreto, sendo os alvos do estudo a resistência à tração, o módulo de elasticidade e a energia de fratura. Os valores definidos na análise foram extrapolados para os outros modelos. Foram determinadas cargas de ruptura e gráficos de carga x deslocamento para os modelos numéricos. Tais resultados foram comparados com os resultados experimentais, apresentando boa correlação, v dos modelos computacionais
Setting performance indicators for coastal marine protected areas: An expert-based methodology
Marine Protected Areas (MPAs) require effective indicators to assess their performance, in
compliance with the goals of relevant national and international commitments. Achieving
and prioritizing shortlists of multidisciplinary indicators demands a significant effort from
specialists to depict the multiple conservation and socioeconomic interests, and the large
complexity of natural systems. The present paper describes a structured expert-based
methodology (process and outputs) to co-define a list of multidisciplinary MPA
performance indicators. This work was promoted by the management authority of
coastal MPAs in mainland Portugal to gather a consensual and feasible list of indicators
that would guide the design of a future national monitoring program. Hence, Portuguese
coastal MPAs served as a case study to develop such a process between 2019 and 2020.
In the end, participants (1) agreed on a shortlist of prioritized indicators (i.e., environmental,
governance, and socioeconomic indicators) and (2) defined minimum monitoring
frequencies for the indicators in this list, compatible with the potential replicability of the
associated survey methods. The present approach recommends that management plans
incorporate monitoring procedures and survey methods, with a validated list of indicators
and associated monitoring periodicity, agreed among researchers, MPA managers and
governance experts. The proposed methodology, and the lessons learned from it, can
support future processes aiming to define and prioritize MPA performance indicatorsFundação para a Ciência e Tecnologia - FCT, European Maritime and
Fisheries Fund (EMFF)info:eu-repo/semantics/publishedVersio
Subversion of early innate antiviral responses during antibody-dependent enhancement of Dengue virus infection induces severe disease in immunocompetent mice
Dengue is a mosquito-borne disease caused by one of four serotypes of Dengue virus (DENV-1–4). Epidemiologic and observational studies demonstrate that the majority of severe dengue cases, dengue hemorrhagic fever and dengue shock syndrome (DHF/DSS), occurs predominantly in either individuals with cross-reactive immunity following a secondary heterologous infection or in infants with primary DENV infections born from dengue-immune mothers, suggesting that B-cell-mediated and antibody responses impact on disease evolution. We demonstrate here that B cells play a pivotal role in host responses against primary DENV infection in mice. After infection, μMT[superscript −/−] mice showed increased viral loads followed by severe disease manifestation characterized by intense thrombocytopenia, hemoconcentration, cytokine production and massive liver damage that culminated in death. In addition, we show that poly and monoclonal anti-DENV-specific antibodies can sufficiently increase viral replication through a suppression of early innate antiviral responses and enhance disease manifestation, so that a mostly non-lethal illness becomes a fatal disease resembling human DHF/DSS. Finally, treatment with intravenous immunoglobulin containing anti-DENV antibodies confirmed the potential enhancing capacity of subneutralizing antibodies to mediate virus infection and replication and induce severe disease manifestation of DENV-infected mice. Thus, our results show that humoral responses unleashed during DENV infections can exert protective or pathological outcomes and provide insight into the pathogenesis of this important human pathogen
Effect of the thermal treatment on the glue-line shear strength of OSB panels
As pesquisas sobre o tratamento t\ue9rmico em pain\ue9is OSB
(oriented strandboard) v\ueam buscando reduzir a higroscopicidade dos
pain\ue9is, bem como aliviar as tens\uf5es geradas durante o
processo de prensagem. Entretanto, o tratamento t\ue9rmico acima de
160\ubaC pode causar inativa\ue7\ue3o da superf\uedcie da
madeira, tornando-a mais lisa, diminuindo a penetra\ue7\ue3o do
adesivo e por conseq\ufc\ueancia, reduzindo a qualidade da
ades\ue3o. O lixamento da superf\uedcie de pain\ue9is OSB pode
tornar a superf\uedcie mais rugosa aumentando a qualidade da
ades\ue3o e a resist\ueancia na linha de cola. O presente estudo
teve como objetivo avaliar a resist\ueancia na linha de cola de
pain\ue9is OSB tratados termicamente, assim como a influ\ueancia do
lixamento na qualidade da colagem dos pain\ue9is. Foram obtidos,
aleatoriamente pain\ue9is comerciais de OSB que foram tratados
termicamente em prensa laboratorial segundo dois n\uedveis
temperaturas (190 e 220\ubaC), tr\ueas tempos de dura\ue7\ue3o
(12, 16 e 20 minutos). Foram cortados 84 corpos-de-prova (CP) sendo que
a metade foi lixada. O ensaio de resist\ueancia ao cisalhamento da
linha de cola foi conduzido segundo ASTM D1037, sendo avaliado o
adesivo resorcinol-formalde\ueddo na gramatura de 360 g/m\ub2. Os
resultados mostraram que o tratamento t\ue9rmico teve influ\ueancia
na resist\ueancia, diminuindo-a levemente em compara\ue7\ue3o ao
material n\ue3otratado. Foi identificado efeito interativo entre a
temperatura e o tempo de tratamento. Entretanto, com a
opera\ue7\ue3o de lixamento esse efeito foi removido e as
diferen\ue7as com a testemunha foram diminu\ueddas. Observou-se que
os ganhos na resist\ueancia com o lixamento foram de at\ue9 15%.
Sendo assim, o tratamento t\ue9rmico apresentou pouca influ\ueancia
na resist\ueancia da linha de cola e o efeito do lixamento
apresentou-se como um processo ben\ue9fico, melhorando a qualidade da
ades\ue3o dos pain\ue9is OSB.Research to improve dimensional stability of oriented strand boards
(OSB) through thermal treatment has been done. It aims to reduce the
higroscopicity of the wood particles as well as to relieve the
compression stresses generated during pressing process. In spite of the
advantages, the thermal treatment above 160\ubaC can inactive the
surface of the wood, reducing the penetration of the adhesive and, this
way, reducing the quality of the adhesion. The sanding of the surface
of OSB panels can remove this effect, increasing the quality of the
adhesion and the glue line strength. The present study aimed to
evaluate the effect of the thermal treatment on the glue-line shear
strength of OSB panels and the effect of the sanding process on this
strength, as well. Commercial OSB were thermally treated according to
two temperature levels (190 and 220\ubaC), three times (12, 16 and 20
minutes). Eighty-four samples were cut, both of them were sanded before
the gluing (resorcinol-formaldehyde, 360 g/m\ub2). The glue-line
shear strength testing was conducted according to ASTM D 1037 standard.
The results reveled that the proposed thermal treatment reduced
slightly the shear strength The interaction factor between temperature
and time on these results was identified. However, sanding process
removed this effect and improved significantly shear strength.
Therefore, the thermical treatment imparted little effect on the
glue-line shear strength, while the sanding process improved the
quality of the adhesion in OSB panels
Co-design of a marine protected area zoning and the lessons learned from it
Marine Protected Areas (MPAs) are a tool to safeguard marine natural systems,
yet their effectiveness depends on how well they are integrated into the existing
socioeconomic context. Stakeholder engagement in MPA design can
contribute to increasing integration. This study focuses on the co-design of
an MPA between researchers, public administration, the private sector, and
non-governmental organizations. The proposed MPA is in Portugal and
includes an area that is a hotspot for biodiversity and economic activities.
This is the first MPA proposal in mainland Portugal co-designed using a
participatory approach. This study highlights the steps of the zoning process
and synthesizes the eight main lessons learned, useful for other cases,
particularly for relatively small coastal MPAs with multiple socioeconomic
activities. Three zoning proposals were developed and discussed within the
participatory process. The proposals considered the best scientific and local
knowledge available and were defined using ecological, socioeconomic, and
shape-area guiding principles. In an iterative manner and following a
participatory approach, compromises with stakeholders were achieved, and a
final proposal, scientifically sound and socially accepted by most stakeholders,
was delivered to the government. The final zoning plan will achieve ambitious
conservation goals, including the largest fully protected area to be declared in
mainland Portugal, while minimizing the impacts on the existing economic activities and promoting its sustainability. This process resulted in valuable
lessons that may be applied elsewhere and guide future MPA implementation
or rezoning of existing ones. These transdisciplinary and participatory
processes can be time and resource-consuming but are vital for ensuring
MPA effectiveness.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio
Applying the Maternal Near Miss Approach for the Evaluation of Quality of Obstetric Care: A Worked Example from a Multicenter Surveillance Study
Objective. To assess quality of care of women with severe maternal morbidity and to identify associated factors. Method. This is a national multicenter cross-sectional study performing surveillance for severe maternal morbidity, using the World Health Organization criteria. the expected number of maternal deaths was calculated with the maternal severity index (MSI) based on the severity of complication, and the standardized mortality ratio (SMR) for each center was estimated. Analyses on the adequacy of care were performed. Results. 17 hospitals were classified as providing adequate and 10 as nonadequate care. Besides almost twofold increase in maternal mortality ratio, the main factors associated with nonadequate performance were geographic difficulty in accessing health services (P < 0.001), delays related to quality of medical care (P = 0.012), absence of blood derivatives (P = 0.013), difficulties of communication between health services (P = 0.004), and any delay during the whole process (P = 0.039). Conclusions. This is an example of how evaluation of the performance of health services is possible, using a benchmarking tool specific to Obstetrics. in this study the MSI was a useful tool for identifying differences in maternal mortality ratios and factors associated with nonadequate performance of care.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Univ Campinas UNICAMP, Sch Med Sci, Dept Obstet & Gynaecol, BR-13083881 Campinas, SP, BrazilCtr Res Reprod Hlth Campinas Cemicamp, BR-13083888 Campinas, SP, BrazilUniv Fed Amazonas, Manaus, Amazonas, BrazilSch Med Sci, CISAM, Recife, PE, BrazilUniv Fed Ceara, Fortaleza, Ceara, BrazilUniv Fed Bahia, Salvador, BA, BrazilHosp Geral Cesar Cals, Fortaleza, Ceara, BrazilHosp Geral Fortaleza, Fortaleza, Ceara, BrazilMaternidade Odete Valadares, Belo Horizonte, MG, BrazilHosp Materno Infantil, Goiania, Go, BrazilInst Materno Infantil Pernambuco, Recife, PE, BrazilUniv Fed Pernambuco, Recife, PE, BrazilUniv Fed Campina Grande, Campina Grande, PB, BrazilUniv Fed Maranhao, Sao Luis, MA, BrazilUniv Fed Parana, BR-80060000 Curitiba, Parana, BrazilUniv Fed Paraiba, BR-58059900 Joao Pessoa, Paraiba, BrazilHosp Maternidade Fernando Magalhaes, Rio de Janeiro, RJ, BrazilUniv Fed Rio Grande do Sul, Porto Alegre, RS, BrazilHosp Maternidade Celso Pierro, Campinas, SP, BrazilInst Fernandes Figueira Fiocruz, Rio de Janeiro, RJ, BrazilHosp Israelita Albert Einstein, São Paulo, BrazilUniv State São Paulo, Botucatu, SP, BrazilJundiai Sch Med, Jundiai, SP, BrazilUniv São Paulo, BR-14049 Ribeirao Preto, SP, BrazilSanta Casa Limeira, Limeira, SP, BrazilSanta Casa Sao Carlos, Sao Carlos, SP, BrazilMaternidade Leonor Mendes de Barros, São Paulo, BrazilUniversidade Federal de São Paulo, São Paulo, BrazilUniversidade Federal de São Paulo, São Paulo, BrazilCNPq: 402702/2008-5Web of Scienc
ATP - bioluminescence as a technique to evaluate the microbiological quality of water in food industry
Skin color and severe maternal outcomes: evidence from the brazilian network for surveillance of severe maternal morbidity
Taking into account the probable role that race/skin color may have for determining outcomes in maternal health, the objective of this study was to assess whether maternal race/skin color is a predictor of severe maternal morbidity. This is a secondary analysis of the Brazilian Network for Surveillance of Severe Maternal Morbidity, a national multicenter cross-sectional study of 27 Brazilian referral maternity hospitals. A prospective surveillance was performed to identify cases of maternal death (MD), maternal near miss (MNM) events, and potentially life-threatening conditions (PLTC), according to standard WHO definition and criteria. Among 9,555 women with severe maternal morbidity, data on race/skin color was available for 7,139 women, who were further divided into two groups: 4,108 nonwhite women (2,253 black and 1,855 from other races/skin color) and 3,031 white women. Indicators of severe maternal morbidity according to WHO definition are shown by skin color group. Adjusted Prevalence Ratios (PRadj - 95%CI) for Severe Maternal Outcome (SMO=MNM+MD) were estimated according to sociodemographic/obstetric characteristics, pregnancy outcomes, and perinatal results considering race. Results. Among 7,139 women with severe maternal morbidity evaluated, 90.5% were classified as PLTC, 8.5% as MNM, and 1.6% as MD. There was a significantly higher prevalence of MNM and MD among white women. MNMR (maternal near miss ratio) was 9.37 per thousand live births (LB). SMOR (severe maternal outcome ratio) was 11.08 per 1000 LB, and MMR (maternal mortality ratio) was 170.4 per 100,000 LB. Maternal mortality to maternal near miss ratio was 1 to 5.2, irrespective of maternal skin color. Hypertension, the main cause of maternal complications, affected mostly nonwhite women. Hemorrhage, the second more common cause of maternal complication, predominated among white women. Nonwhite skin color was associated with a reduced risk of SMO in multivariate analysis. Nonwhite skin color was associated with a lower risk for severe maternal outcomes. This result could be due to confounding factors linked to a high rate of Brazilian miscegenation.2019CNPQ - Conselho Nacional de Desenvolvimento Científico e Tecnológico402702/2008-
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