Boron diffusion and penetration in ultrathin oxide with poly-Sigate

Boron penetration through thin gate oxide down to 17 Å is investigated in this work. Boron penetration is characterized by the amount of flat band shift in a MOS capacitor. The effective diffusion coefficient of boron in these thin oxides is found to be higher than in thicker oxides. The introduction of a moderate dose of fluorine (1×10¹⁵ cm^-2) during gate doping enhances boron penetration in these thin oxides. Compared to as-deposited polycrystalline silicon (poly-Si), crystallized amorphous silicon (α-Si) films display slower boron diffusion in the gate and reduce enhancement of boron penetration due to fluorine. However, crystallized α-Si gate also reduces the amount of dopant activation and leads to extra gate depletion. The tradeoff between dopant activation and boron penetration is discussed     

Chemoprevention of pulmonary carcinogenesis by aerosolized budesonide in female A/J mice

This investigation is part of a continuing effort to develop effective chemoprevention for carcinogenesis of the lung. The present study explores the use of aerosol administrations for this purpose. The agent selected for initial study was the synthetic glucocorticoid budesonide. This selection was based on previous work in which budesonide added to the diet was found to inhibit pulmonary adenoma formation in female A/J mice. However, high dose levels were required, i.e., of the order of 300 microg/kg, of body weight [L. W. Wattenberg and R. D. Estensen, Carcinogenesis (Lond.), 18: 2015-2017, 1997]. For aerosol administration of budesonide, a nose-only technique has been developed that entails nebulization of the compound dissolved in ethanol and subsequent stripping off of the solvent (less than 3 microl ethanol/liter of air remaining at the site of inhalation). The budesonide particles produced by the apparatus had a mass median aerodynamic diameter of less than 1 microm. An experiment has been carried out in which the inhibitory effects of aerosolized budesonide, given for 1 min six times a week, were studied. Concentrations of budesonide of 26, 81, and 148 microg/liter of air (calculated doses of 23, 72, and 126 microg/kg of body weight) were used. The aerosols were started 1 week after three oral administrations of benzo(a)pyrene (2 mg/20 g of body weight) to female A/J mice. All three doses of budesonide resulted in more than 80% inhibition of pulmonary tumor formation compared to the aerosol control and 90% or greater compared to mice not exposed to aerosol. The difference in inhibition is due to the aerosol procedure itself, which produces a reduction in tumor formation. A decrease in splenic weight (evidence of a systemic effect) occurred at all doses of budesonide. To the best of our knowledge, this is the first published effort at the use of aerosol administration to prevent neoplasia of the respiratory tract. The results of the present study show that administration of a potential chemopreventive agent by aerosol at a low dose can inhibit the occurrence of pulmonary carcinogenesis in female A/J mice.     

Bixin and norbixin in human plasma: determination and study of the absorption of a single dose of Annatto food color

A procedure was developed for the detection and determination of bixin and norbixin in human plasma by reversed-phase HPLC with a sensitivity limit of 5 micrograms l-1. A group of seven volunteers ingested a single dose of 1 ml of a commercial Annatto Food Color (16 mg of cis-bixin in soybean oil). The presence of bixin (cis and trans) and norbixin (cis and trans) was demonstrated in the plasma at average levels of 11.6, 10.1, 2.8 and 0 micrograms l-1 of bixin and 48, 58, 53 and 29 micrograms l-1 of norbixin after 2, 4, 6 and 8 h, respectively. Considerable individual variations were observed. Complete plasma clearance generally occurred for bixin by 8 h and for norbixin by 24 h after ingestion of cis-bixin.     

Deactivation of metal exchanged zeolite catalysts during exposure to chlorinated hydrocarbons under oxidizing conditions

Deactivation of modified cation exchanged zeolite catalysts was studied during complete oxidation of methylene chloride, trichloroethylene and carbon tetrachloride over a temperature range of 175 to 400°C. Coking was found to be the cause of deactivation. However, the catalysts could be completely regenerated by oxidation in air at 450°C. Two different formulations of modified cobalt exchanged Y zeolite catalysts were tested to determine the coking and deactivation rates. Increased cation content increased deactivation and coking over a period of about 1000 hours. Changing the type of zeolite from larger pore Y to medium pore mordenite increased deactivation. The type of chlorinated feed also affected coking and deactivation with the rate of deactivation increasing in the order of trichloroethylene> methylene chloride> carbon tetrachloride. Both coking and deactivation increased with decreasing temperature. Higher space velocity produced more deactivation for trichloroethylene oxidation at 275°C. Based on these results a mechanism for coking is proposed with CO as the possible reaction intermediate that leads to the formation of coke.     

THE SYSTEM SODIUM DISILICATE-BARIUM DISILICATE*

The sodium disilicate-barium disilicate join of the ternary system, Na₂O-BaO-SiO₂, has been studied by means of the quenching method, and the phase-equilibrium diagram has been determined. The two compounds form a binary system without intermediate compounds and without appreciable solid solution. The eutectic occurs at approximately 32% of barium disilicate by weight and at a temperature of 797° C. The melting point of barium disilicate was determined as 1418° C. The glasses in the field of stability of barium disilicate show a marked tendency toward devitrification. The refractive indices of the glasses for sodium light were measured by the microscopic immersion method. These varied regularly from 1.505 for sodium disilicate glass to 1.610 for barium disilicate glass. The refractive index-composition curve plotted on a weight percentage basis is definitely convex downward, whereas on a mol percentage basis it is slightly convex upward.     

Charting progress

Logbooks can be considered aggregate databases that registered nurses (RNs) have the primary responsibility of completing in most health care settings. However, RNs may be unaware of the many uses for the information contained in logbooks and the importance of these entries (Paine et al., 1988). Labor and delivery (L&D) logs provide an essential source of vital statistics birth data for the medical records staff. These data bits are used for reporting statistics, projecting trends, and planning future care for pregnant women.