Role of Peritubular Capillaries and Vascular Endothelial Growth Factor in Chronic Allograft Nephropathy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Swimming versus swinging effects in spacetime

Wisdom has recently unveiled a new relativistic effect, called spacetime swimming, where quasirigid free bodies in curved spacetimes can speed up, slow down or deviate their falls by performing local cyclic shape deformations. We show here that for fast enough cycles this effect dominates over a nonrelativistic related one, named here space swinging, where the fall is altered through nonlocal cyclic deformations in Newtonian gravitational fields. We expect, therefore, to clarify the distinction between both effects leaving no room to controversy. Moreover, the leading contribution to the swimming effect predicted by Wisdom is enriched with a higher order term and the whole result is generalized to be applicable in cases where the tripod is in large redshift regions.

Structure formation in the presence of dark energy perturbations

We study non-linear structure formation in the presence of dark energy. The influence of dark energy on the growth of large-scale cosmological structures is exerted both through its background effect on the expansion rate, and through its perturbations. In order to compute the rate of formation of massive objects we employ the spherical collapse formalism, which we generalize to include fluids with pressure. We show that the resulting non-linear evolution equations are identical to the ones obtained in the pseudo-Newtonian approach to cosmological perturbations, in the regime where an equation of state serves to describe both the background pressure relative to density, and the pressure perturbations relative to the density perturbations. We then consider a wide range of constant and time-dependent equations of state (including phantom models) parametrized in a standard way, and study their impact on the non-linear growth of structure. The main effect is the formation of dark energy structure associated with the dark matter halo: non-phantom equations of state induce the formation of a dark energy halo, damping the growth of structures; phantom models, on the other hand, generate dark energy voids, enhancing structure growth. Finally, we employ the Press-Schechter formalism to compute how dark energy affects the number of massive objects as a function of redshift (number counts).

De Sitter Special Relativity: Effects on cosmology

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mass varying neutrinos in supernovae

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cosmological forecasts from photometric measurements of the angular correlation function

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Thermal, structural and optical properties of new tungsten lead-pyrophosphate glasses

Crystalline lead-pyrophosphate precursor was prepared in aqueous solution from lead nitrate and phosphoric acid and characterized by X-ray diffraction, thermogravimetry and Raman scattering. This crystalline lead-phosphate was then used to prepare glass samples in the binary system Pb(2)P(2)O(7)-WO(3). Dependence of WO(3) content on thermal, structural and optical properties were investigated by thermal analysis (DSC), Raman spectroscopy, UV-visible and near-infrared absorption and M-Line technique to access refractive index values. Incorporation of WO(3) in the lead-pyrophosphate matrix enhances the glass transition temperature and thermal stability against devitrification, favors formation of P-O-W bonds and WO(6) clusters. In addition, optical properties are strongly modified with a redshift of the optical bandgap with WO(3) incorporation as well as an increase of the refractive index from 1.89 to 2.05 in the visible. (C) 2011 Elsevier B.V. All rights reserved.

Habermas lendo Peirce

Entre as várias referências feitas ao pensamento de Peirce, ao longo de sua carreira filosófica, dois textos foram tomados como exemplares da leitura que Jürgen Habermas faz do pensamento de Peirce e, ao lado das diferenças encontradas entre os dois textos, dois itens muito importantes se conservam: a verdadeira admiração pela virada pragmática promovida por aquele filósofo e cientista, que será seguida por seu leitor, e a séria restrição feita à progressiva tendência do pensamento de abandonar a intersubjetividade como garantia da objetividade da semiose, dando preferência a uma fundamentação cosmológica para todo conhecimento. Embora esta última restrição pudesse ser criticada em sua pertinência, tanto a admiração manifesta à contribuição feita por Peirce ao pensamento filosófico com sua proposta pragmática, quanto a restrição a um suposto abandono das relações pessoais na base da semiose, sem dúvida, manifestam o viés filosófico de Habermas lendo um autor que ele admira, mas que não pretende seguir como um exegeta.

NUMERICAL STUDY OF A PERTURBED EINSTEIN-DESITTER COSMOLOGICAL MODEL

Given the ever-increasing scale of structures discovered in the universe, we solve Einstein's equations numerically, under simplifying assumptions, to examine how this lack of uniformity affects the metric of Einstein-de Sitter cosmology. The results confirm the qualitative conclusion of Barrow, that a large density contrast is compatible with much smaller metric perturbations. The contribution of this peculiar gravity to the redshift might complicate studies of peculiar motions of galaxies, although it appears that the distortion is small for nearby clusters.

Effect of temperature on the optical properties of GaAsSbN/GaAs single quantum wells grown by molecular-beam epitaxy

GaAsSbN/GaAs strained-layer single quantum wells grown on a GaAs substrate by molecular-beam epitaxy with different N concentrations were studied using the photoluminescence (PL) technique in the temperature range from 9 to 296 K. A strong redshift in optical transition energies induced by a small increase in N concentration has been observed in the PL spectra. This effect can be explained by the interaction between a narrow resonant band formed by the N-localized states and the conduction band of the host semiconductor. Excitonic transitions in the quantum wells show a successive red/blue/redshift with increasing temperature in the 2-100 K range. The activation energies of nonradiative channels responsible for a strong thermal quenching are deduced from an Arrhenius plot of the integrated PL intensity. (C) 2003 American Institute of Physics.

Considerações sobre o câncer localmente avançado de mama (CLAM) acrescidas de identificação dos receptores de estrogênios usando anticorpos monoclonais.

The effects of therapy in locally advanced breast cancer submitted to combined conventional telecobalt therapy plus chemotherapy with cyclophosphamide and 5-fluorouracil were studied in 49 patients. Associated to radical mastectomy in operable cases. Local tumor control was achieved in 86.7%. There were no local recurrences in those submitted to surgery but they reached 21.7% in inoperable patients who received only radiation therapy and chemotherapy. The median follow-up time for dead patients was 29.5 months and for living patients 79.3 months. The index of complete responses was 24.5% and the median disease free interval was 22.9 months. The overall survival rate, between three and five years, was 32.7%. Estrogen receptors were identified by using immunohistochemical assay ER-ICA and monoclonal antibody H222-SP gamma, Abbott. There were no differences in the complete response index, disease free interval and survival rates, among ER-positive and ER-negative patients, explained by the far advanced stage of the disease. ER-positivity was significantly correlated with histological features of the tumors: cell differentiation, presence of elastosis, absence of lymphocytic infiltration and absence of tumor necrosis.

White light emission of Eu3+-based hybrid xerogels

The luminescence spectra and extended x-ray-absorption fine-structure (EXAFS) measurements of a series of Eu3+-based organic/inorganic xerogels were reported and related to the local coordination of the lanthanide cations. The hybrid matrix of these organically modified silicates, classed as U(2000) ureasils, is a siliceous network to which short organic chains containing oxyethylene units are covalently grafted by means of urea bridges. The luminescent centers were incorporated as europium triflate, Eu(CF3SO3)3, and europium bromide, EuBr3, with concentrations 200≥n≥20 and n=80, 40, and 30, respectively - where n is the number of ether oxygens in the polymer chains per Eu3+ cation. EXAFS measurements were carried out in some of the U(2000)nEu(CF3SO3)3 xerogels (n=200, 80, 60, and 40). The obtained coordination numbers N ranging from 12.8, n=200, to 9.7, n=40, whereas the average Eu3+ first neighbors distance R is 2.48-2.49 Å. The emission spectra of these multiwavelength phosphors superpose a broad green-blue band to a series of yellow-red narrow 5D0→7F0-4 Eu3+ lines and to the eye the hybrids appeared to be white, even at room temperature. The ability to tune the emission of the xerogels to colors across the chromaticity diagram is achieved by changing the excitation wavelength and the amount of salt incorporated in the hybrid host. The local environment of Eu3+ is described as a continuous distribution of closely similar low-symmetry network sites. The cations are coordinated by the carbonyl groups of the urea moieties, water molecules, and, for U(2000)nEu(CF3SO3)3, by the SO3 end groups of the triflate anions. No spectral evidences have been found for the coordination by the ether oxygens of the polyether chains. A mean radius for the first coordination shell of Eu3+ is calculated on the basis of the emission energy assignments. The results obtained for U(2000)nEu(CF3SO3)3, 2.4 Å for 90 ≥n≥40 and 2.6 and 2.5 Å for n=30 and 20, respectively, are in good agreement with the values calculated from EXAFS measurements. The energy of the intraconfigurational charge-transfer transitions, the redshift of the 5D0→7F0 line, with respect to the value calculated for gaseous Eu3+, and the hypersensitive ratio between the 5D0→7F2 and 5D0→7F1 transitions, point out a rather low covalency nature of the Eu3+ first coordination shell in these xerogels, comparing to the case of analogous polymer electrolytes modified by europium bromide. ©1999 The American Physical Society.

The influence of the loop between residues 223-235 in beetle luciferase bioluminescence spectra: A solvent gate for the active site of pH-sensitive luciferases

Beetle luciferases emit a wide range of bioluminescence colors, ranging from green to red. Firefly luciferases can shift the spectrum to red in response to pH and temperature changes, whereas click beetle and railroadworm luciferases do not. Despite many studies on firefly luciferases, the origin of pH-sensitivity is far from being understood. Through comparative site-directed mutagenesis and modeling studies, using the pH-sensitive luciferases (Macrolampis and Cratomorphus distinctus fireflies) and the pH-insensitive luciferases (Pyrearinus termitilluminans, Phrixotrix viviani and Phrixotrix hirtus) cloned by our group, here we show that substitutions dramatically affecting bioluminescence colors in both groups of luciferases are clustered in the loop between residues 223-235 (Photinus pyralis sequence). The substitutions at positions 227, 228 and 229 (P. pyralis sequence) cause dramatic redshift and temporal shift in both groups of luciferases, indicating their involvement in labile interactions. Modeling studies showed that the residues Y227 and N229 are buried in the protein core, fixing the loop to other structural elements participating at the bottom of the luciferin binding site. Changes in pH and temperature (in firefly luciferases), as well as point mutations in this loop, may disrupt the interactions of these structural elements exposing the active site and modulating bioluminescence colors. © 2007 The Authors.

Acute antibody-mediated rejection of renal transplant associated with cellular crescents: First case report

Acute antibody-mediated rejection is characterized by histological abnormalities such as glomerulitis, capillaritis, or thrombosis associated with presence of C4d and specific anti-donor antibodies. Reports on the association of glomerular injuries with cellular crescents in antibody-mediated rejection are not found in the literature. We report a unique case of antibody-mediated rejection associated with cellular crescents and suggest that such histological abnormality should be considered in the differential diagnosis of acute antibody-mediated rejection. © 2011 Elsevier Inc.

Anemia at one year is an independent risk factor of graft survival

Background Post-transplant anemia is multifactorial and highly prevalent. Some studies have associated anemia with mortality and graft failure. The purpose of this study was to assess whether the presence of anemia at 1 year is an independent risk factor of mortality and graft survival. Methods All patients transplanted at a single center who survived at least 1 year after transplantation and showed no graft loss (n = 214) were included. Demographic and clinical data were collected at baseline and at 1 year. Patients were divided into two groups (anemic and nonanemic) based on the presence of anemia (hemoglobin<130 g/l in men and 120 g/l in women). Results Baseline characteristics such as age, gender, type of donor, CKD etiology, rejection, andmismatches were similar in both groups. Creatinine clearance was similar in both anemic and nonanemic groups (69.32 ± 29.8 × 75.69 ± 30.5 ml/mim; P = 0.17). A Kaplan- Meier plot showed significantly poorer death-censored graft survival in the anemic group, P = 0.003. Multivariate analysis revealed that anemic patients had a hazard ratio for the graft loss of 3.85 (95% CI: 1.49-9.96; P = 0.005). Conclusions In this study, anemia at 1 year was independently associated with death-censored graft survival and anemic patients were 3.8-fold more likely to lose the graft. © 2010 Springer Science+Business Media, B.V.