Tufts University

About: Tufts University is a education organization based out in Medford, Massachusetts, United States. It is known for research contribution in the topics: Population & Medicine. The organization has 32800 authors who have published 66881 publications receiving 3451152 citations. The organization is also known as: Tufts College & Universitatis Tuftensis.

Essential role for the peroxiredoxin Prdx1 in erythrocyte antioxidant defence and tumour suppression

Abstract: Reactive oxygen species are involved in many cellular metabolic and signalling processes and are thought to have a role in disease, particularly in carcinogenesis and ageing. We have generated mice with targeted inactivation of Prdx1, a member of the peroxiredoxin family of antioxidant enzymes. Here we show that mice lacking Prdx1 are viable and fertile but have a shortened lifespan owing to the development beginning at about 9 months of severe haemolytic anaemia and several malignant cancers, both of which are also observed at increased frequency in heterozygotes. The haemolytic anaemia is characterized by an increase in erythrocyte reactive oxygen species, leading to protein oxidation, haemoglobin instability, Heinz body formation and decreased erythrocyte lifespan. The malignancies include lymphomas, sarcomas and carcinomas, and are frequently associated with loss of Prdx1 expression in heterozygotes, which suggests that this protein functions as a tumour suppressor. Prdx1-deficient fibroblasts show decreased proliferation and increased sensitivity to oxidative DNA damage, whereas Prdx1-null mice have abnormalities in numbers, phenotype and function of natural killer cells. Our results implicate Prdx1 as an important defence against oxidants in ageing mice.

Shape and Crystal-Plane Effects of Nanoscale Ceria on the Activity of Au-CeO2 Catalysts for the Water–Gas Shift Reaction†

Abstract: The water–gas shift (WGS) reaction (CO+H2OQCO2+H2) plays an important role in fuel processing for polymer electrolyte membrane (PEM) fuel-cell applications. The hydrogen in the reformate gas is upgraded by removal of the carbon monoxide, which is a strong poison of the anode catalysts in current PEM fuel cells. Active shift catalysts that are also stable under the operating conditions of practical fuel-cell systems are under intense study, and nanostructured Au-CeO2, first reported by Fu et al. as a promising lowtemperature shift catalyst, holds a prominent position. This catalyst exploits the strong interaction of ceria with finely dispersed and stabilized gold atoms and clusters on the surface of ceria. Gold nanoparticles and clusters that interact strongly with oxide supports were first described by Haruta et al. to be extremely active CO oxidation catalysts. Numerous studies since then have reaffirmed the activity of well-dispersed gold for CO oxidation and many other reactions. While a full mechanism of this catalytic process still needs to be established, even for the simplest of these reactions (CO oxidation), a careful investigation of the reported strong metal–support interaction through structural studies may provide further mechanistic insights as well as rationalize the design of practical catalysts. For the WGS reaction on Au-CeO2, the importance of nanoscale ceria as a support that stabilizes active gold species has been demonstrated recently. Hydrolysis methods for the synthesis of ceria nanocrystals have proven to be powerful for controlling particle size and crystal shape. For example, Yan et al. have obtained single-crystalline CeO2 nanopolyhedra ({111} and {100}), nanorods ({110} and {100}), and nanocubes ({100}) by hydrolysis of cerium(III) salts, combined with a hydrothermal treatment, and have further found that oxygen storage takes place both at the surface and in the bulk for nanorods and nanocubes but is restricted to the surface for nanopolyhedra, just like its bulk ceria counterpart. Trovarelli et al. have studied the rearrangement of CeO2 crystallites under airaging and the exposure of more reactive {100} surfaces for CO oxidation. Very little is known for Au-CeO2 composite polycrystalline nanomaterials with respect to the shape/crystal plane effect of CeO2 on the gold species< activity/stabilization as highly active catalysts for the WGS reaction. Herein, we present activity correlations with the shape (rod, cube, polyhedron) and crystal plane of nanoscale ceria as a support for gold catalysts for this reaction. The interaction between deposited gold and different crystal orientations is investigated at ambient pressure andmonitored by several analytical techniques, including transmission electron microscopy (TEM), high-resolution TEM (HRTEM), X-ray photoelectron spectroscopy (XPS), and temperature-programmed reduction by hydrogen (H2-TPR). Figure 1 depicts our two-step preparation process, which includes hydrothermal synthesis of ceria nanorods, nano-

PC12 Pheochromocytoma Cultures in Neurobiological Research

Abstract: Publisher Summary This chapter presents an overview of PC12 pheochromocytoma cultures in neurobiological research. The PC12 line of rat pheochromocytoma cells promises to be highly useful for studying both chromaffin cells and neurons and, consequently, has been employed in an increasing number of laboratories. PC12 cells propagated in vivo or in culture without nerve-growth factor are readily classifiable as pheochromocytomas by current morphological and chemical criteria. They have no processes and are characterized by numerous secretory granules ranging in diameter up to 350 nm. They also contain total catecholamine stores comparable to those in rat adrenal glands and show intense formaldehyde-induced fluorescence. In addition to catecholamines, PC12 cells contain several other secretory products, some of which have also been reported in human pheochromocytomas. The morphology of the cells and their synthesis, storage, release, and uptake of neurohumoral or neurotransmitter substances can be modulated in a number of ways within the overall chromaffin cell-like phenotype. This chapter reviews the currently known properties of the PC12 line. It also discusses the ways in which it has been and could be exploited to increase the knowledge of neuronal and neurosecretory cells.

Human Amygdala Responsivity to Masked Fearful Eye Whites

Abstract: The amygdala was more responsive to fearful (larger) eye whites than to happy (smaller) eye whites presented in a masking paradigm that mitigated subjects' awareness of their presence and aberrant nature. These data demonstrate that the amygdala is responsive to elements of.