Geometric criteria of hydrogen bonds in proteins and identification of `bifurcated' hydrogen bonds

Empirical criteria for identification of hydrogen bonds wereanalyzed to produce a set of geometrically consistent criteria.For a data set of 30 structures, application of a set of purelygeometrical criteria, along with exclusion of abnormal backboneconformations, also excluded a common interaction of Ser/Thrside chains with Asp/Glu side chains ([ST]/[DE] pairs). Theseinteractions were termed `bifurcated hydrogen bonds/', whichimplies delocalization of a positively charged hydrogen of hydroxylbetween the two acceptor atoms of the carboxylic group. These`bifurcated/' interactions are among the most common packingpatterns for [ST]/[DE] pairs of side chains. Therefore, theidentification of hydrogen bonds cannot be based on geometricalcriteria only and requires introduction of some physico-chemicalcriteria.     

A standardized method for CMOS unit process development

The multipurpose mask set described, which consists of three stepper reticles, contains 95% of all test structures required for CMOS process development and random defect detection, thereby dramatically reducing the stepper reticle inventory and the frequency of reticle changes. Realizing the mask set by two dozen standard unit processes minimizes the feedback loop for defect density data, parametric data and unit process data     

Ochratoxin A in pork kidneys--description of a method

A rapid procedure for the isolation and clean-up on a silica gel column is described for the determination of Ochratoxin A from pork kidneys. The detection limit is 0.3 microgram/kg.     

Rate of cerebrospinal fluid formation, resistance to reabsorption of cerebrospinal fluid, brain tissue water content, and electroencephalogram during desflurane anesthesia in dogs

Propofol decreases intraocular pressure (IOP) and the IOP response to laryngoscopy and intubation, but the mechanisms responsible for this effect have not been reported. The present study examined the effect of propofol on IOP, intraocular fluid formation and outflow facility, and intraocular compliance. Twenty-two white New Zealand rabbits were anesthetized with halothane (0.8%-1.0% inspired concentration) in nitrous oxide (2 L/min) and oxygen (1 L/min). Muscle paralysis was established with pancuronium, and the lungs were mechanically ventilated through a tracheal tube. Twelve rabbits examined under these conditions served as controls. In the treatment group (n = 10), 6 mg/kg propofol followed by 18 mg.kg-1 x h-1 propofol intravenously was added to halothane/nitrous oxide/oxygen anesthesia. In both groups, a series of intraocular infusions was made via a 30-gauge needle in the anterior chamber, and IOP, the rate of aqueous humor formation (Fa), and trabecular outflow facility (Ctr) were determined using conventional analysis. These same measures, as well as intraocular compliance, were determined using a new method of analysis adapted from the manometric technique for determining cerebrospinal fluid dynamics. IOP was 11.3 +/- 1.8 mm Hg (mean +/- SD) in halothane-anesthetized controls and decreased to 9.4 +/- 2.2 mm Hg when propofol was added to halothane anesthesia (P < 0.05). By conventional analysis, Fa was 2.82 +/- 0.94 microL/min and Ctr was 0.121 +/- 0.044 microL.min-1 x mm Hg-1 in controls. After addition of propofol, Fa decreased by 24% to 2.15 +/- 0.62 microL/min (P < 0.05) and Ctr decreased by 18% to 0.099 +/- 0.034 microL.min-1 x mm Hg-1 (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)