University at Buffalo

About: University at Buffalo is a education organization based out in Buffalo, New York, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 33773 authors who have published 63840 publications receiving 2278954 citations. The organization is also known as: UB & State University of New York at Buffalo.

Regulation of vitamin C transport.

Abstract: ▪ Abstract Ascorbic acid and dehydroascorbic acid (DHAA, oxidized vitamin C) are dietary sources of vitamin C in humans. Both nutrients are absorbed from the lumen of the intestine and renal tubules by, respectively, enterocytes and renal epithelial cells. Subsequently vitamin C circulates in the blood and enters all of the other cells of the body. Concerning flux across the plasma membrane, simple diffusion of ascorbic acid plays only a small or negligible role. More important are specific mechanisms of transport and metabolism that concentrate vitamin C intracellularly to enhance its function as an enzyme cofactor and antioxidant. The known transport mechanisms are facilitated diffusion of DHAA through glucose-sensitive and -insensitive transporters, facilitated diffusion of ascorbate through channels, exocytosis of ascorbate in secretory vesicles, and secondary active transport of ascorbate through the sodium-dependent vitamin C transporters SVCT1 and SVCT2 proteins that are encoded by the genes Slc23a...

Process for preparing macroscopic quantities of brightly photoluminescent silicon nanoparticles with emission spanning the visible spectrum

Abstract: Silicon nanoparticles with bright visible photoluminescence have been prepared by a new combined vapor phase and solution phase process, using only inexpensive commodity chemicals. CO2 laser induced pyrolysis of silane was used to produce Si nanoparticles at high rates (20−200 mg/h). Particles with an average diameter as small as 5 nm were prepared directly by this vapor phase (aerosol) synthesis. Etching these particles with mixtures of hydrofluoric acid (HF) and nitric acid (HNO3) reduced the size and passivated the surface of these particles such that after etching they exhibited bright visible luminescence at room temperature. The wavelength of maximum photoluminescence (PL) intensity was controlled from above 800 nm to below 500 nm by controlling the etching time and conditions. Particles with blue emission (maximum PL intensity at 420 nm) were prepared by rapid thermal oxidation of orange-emitting particles. The particle synthesis methods; steady-state photoluminescence spectra; results of their cha...

Political Costs and Earnings Management of Oil Companies in the 1990 Persian Gulf Crisis

Abstract: This study investigates whether firms that expect increases in earnings resulting from sudden product price increases use accounting accruals to reduce earnings and, thus, political sensitivity. Specifically, oil firms' accruals are analyzed in a period of rapid gasoline price increases during the 1990 Persian Gulf crisis. Our results show that oil firms expected to profit from the crisis used accruals to reduce their reported quarterly earnings during the Gulf crisis. In contrast to previous research, we find that the tendency to release good earnings news early, documented in prior research, is reversed for oil firms during the Gulf crisis. This finding suggests that the benefit of disclosing "good news" (i.e., earnings increases) early may have been outweighed by the political costs associated with timely releases of the information.