Scavenging Effects of Dexrazoxane on Free Radicals

Dexrazoxane (ICRF-187) has been clinically used to reduce doxorubicin-induced cardiotoxicity for more than 20 years. It has been proposed that dexrazoxane may act through its rings-opened hydrolysis product ADR-925, which can either remove iron from the iron-doxorubicin complex or bind to free iron, thus preventing iron-based oxygen radical formation. However, it is not known whether the antioxidant actions of dexrazoxane are totally dependent on its metabolization to its rings-opened hydrolysis product and whether dexrazoxane has any effect on the iron-independent oxygen free radical production. In this study, we examined the scavenging effect of dexrazoxane on hydroxyl, superoxide, lipid, DPPH and ABTS+ free radicals in vitro solution systems. The results demonstrated that dexrazoxane was an antioxidant that could effectively scavenge these free radicals and the scavenging effects of dexrazoxane did not require the enzymatic hydrolysis. In addition, dexrazoxane was capable to inhibit the generation superoxide and hydroxyl radicals in iron free reaction system, indicating that the antioxidant properties of dexrazoxane were not solely dependent on iron chelation. Thus the application of dexrazoxane should not be limited to doxorubicin-induced cardiotoxicity. Instead, as an effective antioxidant that has been clinically proven safe, dexrazoxane may be used in a broader spectrum of diseases that are known to be benefited by antioxidant treatments

A memória da luz : customizações e encontros com o espectador

Tese (doutorado)—Universidade de Brasília, Instituto de Artes, Departamento de Artes Visuais, 2017.O presente trabalho fala do desenvolvimento e aplicação de simulacros computacionais da luz como opção poética que é estética e empiricamente investigada de modo a envolver a comparação de minhas percepções e meus horizontes, como artista, com os de meus espectadores, como forma de encontrar aproximações e distâncias entre essas percepções e horizontes enquanto criações necessariamente implicadas na fruição esteticamente qualificada desses simulacros, em favor de um maior entendimento sobre o que poderia ser um encontro ou comunicação possível entre autor e receptor e na expectativa de obter, pelo somatório de percepções e horizontes colhidos desses espectadores, uma revelação paulatina das propostas artísticas correspondentes a esses simulacros.This work is about the development and application of computer light simulacra as poetic option that is aesthetically and empirically investigated in a way that involves the comparison of my perceptions and horizons, as an artist, with those of my spectators, as a way to find the proximities and distances between those perceptions and horizons as creations necessarily implied in the fruition aesthetically qualified of these simulacra, in favor of a greater understanding of what could be a possible encounter or communication between author and receiver and in the expectation of a gradual revelation of the artistic proposals corresponding to these simulacra, by the sum of perceptions and horizons taken from those spectators

One Gap. Two Gaps. Universality in High Temperature Superconductors

One of the goals in contemporary condensed matter physics, is to understand various emergent properties of matter due to many body interactions --- e.g. superfluidity, superconductivity, colossal magnetoresistance and so on. Superconductors, discovered more than a century ago, have the remarkable property of zero resistance to electrical current below certain temperatures, commonly known as critical temperatures (Tc). The Tc value for conventional superconductor is relatively low, less than 30K, while it could be as high as 150K for a new class of materials, known as high temperature superconductors (HTSCs). The mechanism behind superconductivity in conventional superconductors can be well understood under the framework of the famous BCS (Bardeen, Cooper, Schrieffer) theory, while for HTSCs, it is still a mystery. Angle Resolved Photoemission Spectroscopy (ARPES), which directly probes the momentum space structure of a physical system, has been instrumental to provide new insights in understanding various strongly correlated systems --- particularly the HTSC materials. In this thesis, I will present and discuss our recent research on various Bi2212 HTSCs using ARPES. For the first time, we provided the spectroscopic evidence for the three distinct phases in the normal state of Bi2212 HTSC. By comparing the systematic ARPES data of pure Bi2212 and cation-doped Bi2212 HTSCs, we found that introducing different elements would not only change the carrier concentration, but also create additional disorders inside the system, which is responsible for the different spectroscopic properties. In additon, we found that the deviation from d-wave gap anisotropy in cation-doped Bi2212 is correlated to the lack of coherent spectral peaks. I will also give an overview of the synthesis of La-doped Bi2212 single crystals by using floating zone technique. Even though the La content varies along the crystal growth direction, our crystals are of the pure Bi2212 crystal structure, and their carrier concentrations are in the underdoped side of the superconducting dome

Significant longevity-extending effects of EGCG on Caenorhabditis elegans under stress

Epigallocatechin gallate (EGCG), a main active ingredient of green tea, is believed to be beneficial in association with anticarcinogenesis, antiobesity, and blood pressure reduction. Here we report that EGCG extended Caenorhabditis elegans longevity under stress. Under heat stress (35 degrees C), EGCG improved the meal) longevity by 13.1% at 0.1 mu g/ml, 8.0% at 1.0 mu g/ml, and 11.8% at 10.0 mu g/ml. Under oxidative stress, EGCG could improve the mean longevity of C. elegans by 172.9% at 0.1 mu g/ml, 177.7% at 1.0 mu g/ml, and 88.5% at 10.0 mu g/ml. However, EGCG could not extend the life span of C. elegans under normal culture conditions. Further studies demonstrated that the significant longevity-extending effects of EGCG on C elegans could be attributed to its in vitro and in vivo free radical-scavenging effects and its up-regulating effects on stress-resistance-related proteins, including superoxide dismutase-3 (SOD-3) and heat shock protein-16.2 (HSP-16.2), in transgenic C elegans with SOD-3: :green fluorescent protein (GFP) and HSP-16.2: :GFP expression. Quantitative real-time PCR results showed that the up-regulation of aging-associated genes such as daf-16, sod-3, and skn-1 could also contribute to the stress resistance attributed to EGCG. As the death rate of a population is closely related to the mortality caused by external stress, it could be concluded that the survival-enhancing effects of EGCG on C. elegans under stress are very important for antiaging research.Epigallocatechin gallate (EGCG), a main active ingredient of green tea, is believed to be beneficial in association with anticarcinogenesis, antiobesity, and blood pressure reduction. Here we report that EGCG extended Caenorhabditis elegans longevity under stress. Under heat stress (35 degrees C), EGCG improved the meal) longevity by 13.1% at 0.1 mu g/ml, 8.0% at 1.0 mu g/ml, and 11.8% at 10.0 mu g/ml. Under oxidative stress, EGCG could improve the mean longevity of C. elegans by 172.9% at 0.1 mu g/ml, 177.7% at 1.0 mu g/ml, and 88.5% at 10.0 mu g/ml. However, EGCG could not extend the life span of C. elegans under normal culture conditions. Further studies demonstrated that the significant longevity-extending effects of EGCG on C elegans could be attributed to its in vitro and in vivo free radical-scavenging effects and its up-regulating effects on stress-resistance-related proteins, including superoxide dismutase-3 (SOD-3) and heat shock protein-16.2 (HSP-16.2), in transgenic C elegans with SOD-3: :green fluorescent protein (GFP) and HSP-16.2: :GFP expression. Quantitative real-time PCR results showed that the up-regulation of aging-associated genes such as daf-16, sod-3, and skn-1 could also contribute to the stress resistance attributed to EGCG. As the death rate of a population is closely related to the mortality caused by external stress, it could be concluded that the survival-enhancing effects of EGCG on C. elegans under stress are very important for antiaging research. (C) 2008 Elsevier Inc. All rights reserved

Effects of Alpine Wetland Landscapes on Regional Climate on the Zoige Plateau of China

The differences in the air temperature, precipitation, evaporation, and relative humidity between wetlands and nonwetlands were analyzed to investigate the effects of alpine wetlands on regional climate. Meanwhile, the changes in precipitation and surface runoff fluxes before and after the typical wetland degradation were discussed, and the effects of wetland degradation on soil organic carbon were assessed. Correlation and regression analyses were applied to exhibit the relationships between wetland landscape areas and meteorological factors. Our results showed that the cooling effects of wetlands on ambient environment were very obvious, and soil temperature could be higher in the area with less surrounding wetland area. The evaporation capacity and relative humidity in wetlands were higher compared to the surrounding non-wetlands. Precipitation and surface runoff flux decreased due to serious wetland degradation, indicating that wetland degradation or expansion had close relation with regional precipitation. Once peat soils were converted to meadow soils or Aeolian sandy soils, soil organic carbon (SOC) would decline linearly. Correlation and regression analyses showed that there were significant correlations between wetland landscape areas and the annual average air temperature, the average air temperature in growing seasons, and the evaporation in growing seasons (P<0.05)