Aplicação da geoestatística em dados de capacidade de troca de cátions.

A Capacidade de Troca de Cátions (CTC) é um importante atributo dos solos, pois a disponibilidade de nutrientes para as plantas é permitida através da propriedade de troca de cátions. O presente trabalho teve como objetivo identificar a dependência espacial da CTC e fazer uso das técnicas de Geoestatística para esta variável. O levantamento amostral foi realizado no município de Campos dos Goytacazes, no estado do Rio de Janeiro, foram coletadas amostras de forma regionalizadas, com trado holandês, em uma malha regular, distando 900 metros para cada coordenada geográfica: norte e leste, esta malha foi idealizada com espaçamento de 50 metros, totalizando 273 amostras que após as análises iniciais foram reduzidas a 240 amostras, sem a presença de dados discrepantes. Os dados foram submetidos às análises descritivas exploratórias, com o uso do box-plot, testes de normalidade e gráficos de controle. Posteriormente, foram realizadas as análises geoestatísticas retirandose as tendências linear e quadrática, determinação do semivariograma que melhor representa os dados, krigagem ordinária e construção de mapas da área amostral. Observou-se que a CTC possui dependência espacial e que o semivariograma que melhor representa os dados é o modelo exponencial. Através do mapa amostral pôde-se analisar a interpolação realizada por krigagem, representando satisfatoriamente a área amostral

Glucose regulation and face recognition deficits in older adults: the role of attention

The present study investigated the perceptual, attentional and memory processes underlying face recognition deficits observed in older adults with impaired glucoregulation. Participants were categorised as good glucoregulators or poor glucoregulators on the basis of an oral glucose tolerance test (OGTT). Using event-related potential (ERP) methodology, 23 participants (18 females, range = 62 to 88 years old, mean age = 73.87 years old, SD = 8.41) performed a 2-stimulus oddball task. Participants were asked to rate and memorise 10 ‘target’ faces, which were then presented amongst 120 unfamiliar foils. Behavioural results indicated that good glucoregulators were significantly more accurate at recognising target faces. ERP markers of early visual perception (the P1 and N170 components) and memory formation (the P3 component) were unaffected by glucoregulatory efficiency. The P2 component, an index of attentional processing, was larger and delayed in the poor glucoregulators. To the best of our knowledge, the present study is the first to suggest that face recognition deficits in poor glucoregulators may be due to impairments in attentional processing

Aplicação de métodos geoestatísticos na determinação da variabilidade espacial do teor de argila.

É comum encontrar em solos brasileiros variabilidade na textura e nos macro e micronutrientes. Em experimentos de campo, as amostragens são realizadas dentro de cada parcela aleatoriamente e, dada a variabilidade destes solos, devido às manchas de fertilidade, não são detectadas diferenças estatísticas entre os tratamentos. O objetivo deste trabalho foi estudar A identificação da dependência foi verificada pelo uso do semivariograma. Em geral, variáveis que apresentam grande variabilidade impossibilitam, na maioria das vezes, a detecção de reais diferenças estatísticas entre os efeitos de tratamentos. A consideração de amostras georreferenciadas é uma abordagem importante na análise de dados desta natureza. Foram estudados três modelos de semivariograma sendo que, aquele que melhor se ajustou aos dados de argila foi o exponencial apresentando menor variância espacial e menor quadrado médio do erro

Aplicação de métodos geoestatísticos na análise do teor de silte do solo.

Sabe-se que variáveis regionalizadas são funçõess que variam de um lugar a outro no espaço com certa similaridade de continuidade, cujos valores estão relacionados de algum modo com a posição espacial. Em função disso, este trabalho se propõe a estudar a aplicação de métodos geoestatísticos, para tratamento de variáveis georreferenciadas , em dados de que compõe a fração do solo como o silte fornecidos pela Embrapa Solos

Canine distemper virus induces apoptosis in cervical tumor derived cell lines

Apoptosis can be induced or inhibited by viral proteins, it can form part of the host defense against virus infection, or it can be a mechanism for viral spread to neighboring cells. Canine distemper virus (CDV) induces apoptotic cells in lymphoid tissues and in the cerebellum of dogs naturally infected. CDV also produces a cytopathologic effect, leading to apoptosis in Vero cells in tissue culture. We tested canine distemper virus, a member of the Paramyxoviridae family, for the ability to trigger apoptosis in HeLa cells, derived from cervical cancer cells resistant to apoptosis. To study the effect of CDV infection in HeLa cells, we examined apoptotic markers 24 h post infection (pi), by flow cytometry assay for DNA fragmentation, real-time PCR assay for caspase-3 and caspase-8 mRNA expression, and by caspase-3 and -8 immunocytochemistry. Flow cytometry showed that DNA fragmentation was induced in HeLa cells infected by CDV, and immunocytochemistry revealed a significant increase in the levels of the cleaved active form of caspase-3 protein, but did not show any difference in expression of caspase-8, indicating an intrinsic apoptotic pathway. Confirming this observation, expression of caspase-3 mRNA was higher in CDV infected HeLa cells than control cells; however, there was no statistically significant change in caspase-8 mRNA expression profile. Our data suggest that canine distemper virus induced apoptosis in HeLa cells, triggering apoptosis by the intrinsic pathway, with no participation of the initiator caspase -8 from the extrinsic pathway. In conclusion, the cellular stress caused by CDV infection of HeLa cells, leading to apoptosis, can be used as a tool in future research for cervical cancer treatment and control

Membrane Cholesterol Regulates Lysosome-Plasma Membrane Fusion Events and Modulates Trypanosoma cruzi Invasion of Host Cells

Trypanosoma cruzi, is the etiological agent of a neglected tropical malady known as Chagas' disease, which affects about 8 million people in Latin America. 30–40% of affected individuals develop a symptomatic chronic infection, with cardiomyopathy being the most prevalent condition. T. cruzi utilizes an interesting strategy for entering cells: T. cruzi enhances intracellular calcium levels, which in turn trigger the exocytosis of lysosomal contents. Lysosomes then donate their membrane for the formation of the parasitophorous vacuole. Membrane rafts, cholesterol-enriched microdomains in the host cell plasma membrane, have also been implicated in T. cruzi invasion process. Since both plasma membrane and lysosomes collaborate in parasite invasion, we decided to study the importance of these membrane domains for lysosomal recruitment and fusion during T. cruzi invasion into host cells. Our results show that drug dependent depletion of plasma membrane cholesterol changes raft organization and induces excessive lysosome exocytosis in the earlier stages of treatment, leading to a depletion of lysosomes near the cell cortex, which in turn compromises T. cruzi invasion. Based on these results, we propose that cholesterol depletion leads to unregulated exocytic events of pre-docked lysosomes, reducing lysosome availability at the cell cortex and consequently compromising T. cruzi infection

Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

Superparamagnetic iron oxide nanoparticles can providemultiple benefits for biomedical applications in aqueous environments such asmagnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.status: publishe

Effect of SGLT2 inhibitors on stroke and atrial fibrillation in diabetic kidney disease: Results from the CREDENCE trial and meta-analysis

BACKGROUND AND PURPOSE: Chronic kidney disease with reduced estimated glomerular filtration rate or elevated albuminuria increases risk for ischemic and hemorrhagic stroke. This study assessed the effects of sodium glucose cotransporter 2 inhibitors (SGLT2i) on stroke and atrial fibrillation/flutter (AF/AFL) from CREDENCE (Canagliflozin and Renal Events in Diabetes With Established Nephropathy Clinical Evaluation) and a meta-Analysis of large cardiovascular outcome trials (CVOTs) of SGLT2i in type 2 diabetes mellitus. METHODS: CREDENCE randomized 4401 participants with type 2 diabetes mellitus and chronic kidney disease to canagliflozin or placebo. Post hoc, we estimated effects on fatal or nonfatal stroke, stroke subtypes, and intermediate markers of stroke risk including AF/AFL. Stroke and AF/AFL data from 3 other completed large CVOTs and CREDENCE were pooled using random-effects meta-Analysis. RESULTS: In CREDENCE, 142 participants experienced a stroke during follow-up (10.9/1000 patient-years with canagliflozin, 14.2/1000 patient-years with placebo; hazard ratio [HR], 0.77 [95% CI, 0.55-1.08]). Effects by stroke subtypes were: ischemic (HR, 0.88 [95% CI, 0.61-1.28]; n=111), hemorrhagic (HR, 0.50 [95% CI, 0.19-1.32]; n=18), and undetermined (HR, 0.54 [95% CI, 0.20-1.46]; n=17). There was no clear effect on AF/AFL (HR, 0.76 [95% CI, 0.53-1.10]; n=115). The overall effects in the 4 CVOTs combined were: Total stroke (HRpooled, 0.96 [95% CI, 0.82-1.12]), ischemic stroke (HRpooled, 1.01 [95% CI, 0.89-1.14]), hemorrhagic stroke (HRpooled, 0.50 [95% CI, 0.30-0.83]), undetermined stroke (HRpooled, 0.86 [95% CI, 0.49-1.51]), and AF/AFL (HRpooled, 0.81 [95% CI, 0.71-0.93]). There was evidence that SGLT2i effects on total stroke varied by baseline estimated glomerular filtration rate (P=0.01), with protection in the lowest estimated glomerular filtration rate (45 mL/min/1.73 m2]) subgroup (HRpooled, 0.50 [95% CI, 0.31-0.79]). CONCLUSIONS: Although we found no clear effect of SGLT2i on total stroke in CREDENCE or across trials combined, there was some evidence of benefit in preventing hemorrhagic stroke and AF/AFL, as well as total stroke for those with lowest estimated glomerular filtration rate. Future research should focus on confirming these data and exploring potential mechanisms