511 research outputs found

    Strictly singular operators and isomorphisms of Cartesian products of power series spaces

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    V. P. Zahariuta, in 1973, used the theory of Fredholm operators to develop a method to classify Cartesian products of locally convex spaces. In this work we modify his method to study the isomorphic classification of Cartesian products of the kind E0p(a)×E„ q(b) where 1 ÂŁ p,q ÂŁ „, p Âč q, a = (an)n=1„ and b = (bn)n=1„ are sequences of positive numbers and E0p(a), E„ q (b) are respectively lp-finite and lq-infinite type power series spaces

    Synthesis of Phosporus Included Multiwalled Carbon Nanotubes by Pyrolysis of Sucrose

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    Cataloged from PDF version of article.Multiwalled carbon nanotubes (MWCNT) were synthesized by a pyrolysis route which involves a dehydration step using phosphoric acid. The resultants were found to be mostly containing amorphous carbon with scattered MWCNTs using scanning electron and transmission electron microscopy techniques. These MWCNTs were smaller in size and limited in quantity compared to the ones synthesized using other common precursors. Energy dispersive X-ray and electron energy loss spectroscopy analysis indicated the presence of phosphorus both at the MWCNT sidewalls and in the catalyst particles encapsulated inside the MWCNTs. In addition, a comparative investigation for sulfur and phosphorus inclusion to the sidewalls of MWCNTs was carried out using density functional theory calculations. The results of the computational study showed that both phosphorus and sulfur atoms prefer to bind among themselves rather than adsorbing directly on carbon nanotubes (CNT). Furthermore, cluster calculations revealed that phosphorus atoms more likely form carbonaceous clusters which result in a decrease in the number of free carbon atoms that can be used for CNT formation. Therefore, we concluded that MWCNT growth might be hindered (promoted) in a phosphorus (sulfur) rich environment which results in needle like phosphorus containing MWCNTs

    Asymptomatic giant coronary aneurysm in an adolescent with Behcet's syndrome

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    <p>Abstract</p> <p>Objective</p> <p>Behcet's is an idiopathic multi-organ syndrome, which may have onset during childhood. Vascular involvement is uncommon, with rarely reported coronary aneurysm formation. We present a case report of a teenager girl who developed recalcitrant life-threatening Behcet's vasculitis, involving both small and large venous and arterial systems including a giant coronary aneurysm.</p> <p>Case report</p> <p>De-identified data were collected retrospectively in case report format. Although our sixteen year old female with Behcet's vasculitis had resolution of many arterial aneurysms, she had persistent venous thrombosis of large vessels, as well as persistent, giant arterial aneurysms requiring intra-arterial coiling of a lumbar artery and coronary bypass grafting despite intensive immunosuppression including glucocorticoids, cyclophosphamide, infliximab, methotrexate, azathioprine and intravenous immunoglobulin.</p> <p>Conclusions</p> <p>Vascular manifestations may be seen in Behcet's syndrome, including asymptomatic coronary aneurysm, which may be refractory to immunosuppression and ultimately require surgical intervention. Increased awareness is essential for prompt diagnosis and management.</p

    DNA damage in children and adolescents with cardiovascular disease risk factors

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    The risk of developing cardiovascular disease (CVD) is related to lifestyle (e.g. diet, physical activity and smoking) as well as to genetic factors. This study aimed at evaluating the association between CVD risk factors and DNA damage levels in children and adolescents. Anthropometry, diet and serum CVD risk factors were evaluated by standard procedures. DNA damage levels were accessed by the comet assay (Single cell gel electrophoresis; SCGE) and cytokinesis-blocked micronucleus (CBMN) assays in leukocytes. A total of 34 children and adolescents selected from a population sample were divided into three groups according to their level of CVD risk. Moderate and high CVD risk subjects showed significantly higher body fat and serum CVD risk markers than low risk subjects (PO risco de desenvolver doença cardiovascular (DCV) estĂĄ relacionado ao estilo de vida (por exemplo, dieta, atividade fĂ­sica e tabagismo), bem como a fatores genĂ©ticos. Este estudo teve como objetivo avaliar a associação entre fatores de risco cardiovascular e os nĂ­veis de danos ao DNA em crianças e adolescentes. Antropometria, dieta e fatores de risco para DCV foram avaliados atravĂ©s de procedimentos padrĂŁo. NĂ­veis de danos no DNA foram avaliados atravĂ©s do ensaio cometa (eletroforese de cĂ©lula Ășnica; EC) e do teste de micronĂșcleos em leucĂłcitos. Um total de 34 crianças e adolescentes, selecionados a partir de uma amostra populacional, foram divididos em trĂȘs grupos, de acordo com seu nĂ­vel de risco de DCV. IndivĂ­duos com nĂ­veis moderado e alto risco para DCV apresentaram de forma significativa maiores nĂ­veis de gordura corporal e de marcadores sĂ©ricos de risco cardiovascular que indivĂ­duos de baixo risco (P <0,05). IndivĂ­duos de alto risco tambĂ©m mostraram um aumento significativo de danos ao DNA, de acordo com o EC, mas nĂŁo de acordo com o teste de micronĂșcleos, do que indivĂ­duos de risco baixo e moderado. A vitamina C consumida foi inversamente correlacionada com os danos ao DNA avaliados pelo EC, e o nĂșmero de micronĂșcleos foi inversamente correlacionado com a ingestĂŁo de ĂĄcido fĂłlico. Os resultados obtidos indicam um aumento de danos no DNA que pode ser consequente do estresse oxidativo em indivĂ­duos jovens com fatores de risco para DCV, indicando que o nĂ­vel de danos no DNA pode auxiliar na avaliação do risco de DCV

    Overdiagnosis and overtreatment of early detected prostate cancer

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    Early detection of prostate cancer is associated with the diagnosis of a considerable proportion of cancers that are indolent, and that will hardly ever become symptomatic during lifetime. Such overdiagnosis should be avoided in all forms of screening because of potential adverse psychological and somatic side effects. The main threat of overdiagnosis is overtreatment of indolent disease. Men with prostate cancer that is likely to be indolent may be offered active surveillance. Evaluation of active surveillance studies and validation of new biological parameters for risk assessment are expected

    The Neurotrophic Receptor Ntrk2 Directs Lymphoid Tissue Neovascularization during Leishmania donovani Infection

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    The neurotrophic tyrosine kinase receptor type 2 (Ntrk2, also known as TrkB) and its ligands brain derived neurotrophic factor (Bdnf), neurotrophin-4 (NT-4/5), and neurotrophin-3 (NT-3) are known primarily for their multiple effects on neuronal differentiation and survival. Here, we provide evidence that Ntrk2 plays a role in the pathologic remodeling of the spleen that accompanies chronic infection. We show that in Leishmania donovani-infected mice, Ntrk2 is aberrantly expressed on splenic endothelial cells and that new maturing blood vessels within the white pulp are intimately associated with F4/80hiCD11bloCD11c+ macrophages that express Bdnf and NT-4/5 and have pro-angiogenic potential in vitro. Furthermore, administration of the small molecule Ntrk2 antagonist ANA-12 to infected mice significantly inhibited white pulp neovascularization but had no effect on red pulp vascular remodeling. We believe this to be the first evidence of the Ntrk2/neurotrophin pathway driving pathogen-induced vascular remodeling in lymphoid tissue. These studies highlight the therapeutic potential of modulating this pathway to inhibit pathological angiogenesis

    Cervico-vaginal immunoglobulin g levels increase post-ovulation independently of neutrophils

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    The prevalence of sexually transmitted infections (STIs) is often higher in females than in males. Although the reproductive cycle profoundly modulates local immunity in the female reproductive tract (FRT) system, significant gaps in our knowledge of the immunobiology of the FRT still exist. An intriguing and frequently observed characteristic of the FRT is the predominant presence of immunoglobulin (Ig) G in cervico-vaginal secretions. We show here that in the mouse, IgG accumulation was enhanced approximately 5-fold post-ovulation, and was accompanied by an influx of neutrophils into the FRT. To determine whether these two events were causally related, we performed short-term neutrophil depletion experiments at individual stages throughout the estrous cycle. Our results demonstrate that neutrophils were not necessary for cycle-dependent tissue remodeling and cycle progression and that cycle-dependent IgG accumulation occurred independent of neutrophils. We thus conclude that neutrophil influx and IgG accumulation are independent events that occur in the FRT during the reproductive cycle
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