Role of water temperature in the regulation of water intake.

Performed 3 experiments on small groups (n = 2-6) of thirsty Carworth female albino rats. Cool water suppressed water intake. The suppression was apparent from the 1st min of drinking. Suppression occurred for both short (20-min) and long (100-min) daily drinking sessions, and occurred whether the water was available from a sipper tube or a bowl. When cellular hydration was delayed by giving Ss isotonic saline instead of water, the suppression by cooling was enhanced. Cool-water suppression of water intake appears to be a short-latency satiety mechanism that anticipates cellular and extracellular hydration. (27 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Friction reduction degradation in dilute poly(ethylene oxide) solutions

Degradation of friction-reducing effectiveness of dilute poly(ethylene oxide) solutions subjected to continuous agitation is examined in disk flow. A residual or steady-state effectiveness is observed which disappears only at a sufficiently high Reynolds number. The onset of friction reduction appears to occur within the transition region and seems to be independent of solution concentration. The onset of degradation also appears to be independent of concentration. Prior shear working is shown to have a significant effect on residual friction-reducing effectiveness only when the shear working is performed in a more intense shear field than that in which the friction-reducing effectiveness is evaluated. Degradation of friction-reducing effectiveness is compared to corresponding changes in viscosity-average molecular weight. The experimental results are interpreted in terms of a model of the interaction between polymer molecules and the turbulent flow field.     

A non-lensed fiber-optic resonance-enhanced multiphoton ionization probe

We have developed a miniature fiber-optic probe with no focusing optics for in situ analysis of volatile organic compounds (VOCs). The probe uses an optical fiber to transmit a laser pulse to a vapor sample causing it to ionize adjacent to the fiber tip through a resonance-enhanced multiphoton ionization (REMPI) process. The distal end of the optical fiber is contained co-axially within 2-mm-inner-diameter stainless steel tubing that serves as an electrode. The electrode is biased at a high positive potential to collect electrons. The current generated is shown to be proportional over about two orders of magnitude to the concentration of the species ionized. Visible wavelength REMPI spectroscopy is used to determine probe sensitivities of 20 ppb (benzene) and 43 ppb (toluene). Designing the probe without focusing optics specifies an achromatic ionization region constant in size and position as the laser wavelength is scanned, which simplifies data collection and reduction. Focusing achromatic systems are discussed and the potential signal improvement is estimated.     

Upper extremity replantation: current concepts and patient selection

Dramatic advances in replantation and microsurgery have somewhat altered the criteria we use in selecting patients to be candidates for upper extremity replantation surgery. We suggest that contraindications for such replantation are: presence of associated life-threatening injuries; serious anesthetic risk; preexisting medical or psychiatric problems; previous injury or disease of the amputated part; warm ischemic time greater than 6-8 hours for extremities or greater than 10-12 hours for digits; and single-digit amputations (except thumb, for grasp). Replantation is feasible when: amputated part is properly preserved; injury type is sharp amputation, mild to moderate crush, or selected avulsion, and amputation is proximal to the DIP joint. Careful preservation of the amputated part, not in dry ice, is mandatory. On an individual basis, the decision to attempt replantation rests on the prediction that the patient may have better function with such surgery than with a prosthesis.     

Metabolic Fate of the Environmental Mutagen 3-Nitrofluoranthene in the Rat

3-Nitrofluoranthene, a potent environmental mutagen, was administered to rats intraperitoneally at 10 mg/kg, labelled with ¹⁴C. Urine contained 15 to 20% of the dose, eliminated mainly within the first 24 hours after dosing. Over 95% of the radioactivity in unhydrolysed urine chromatographed with the solvent front in a reverse-phase HPLC system, indicating extensive conjugation. After hydrolysis with β-glucuronidase (containing sulfatase) and concentration on C18-Sep-Pak, urine was fractionated by HPLC for further characterization. NMR analysis of the metabolite fractions indicated that positions 4, 8 and 9 were major sites of oxidation. Both acetamide and amine derivatives were formed. The finding of multiple oxidation and incomplete acetylation is in contrast to the fate of 1-nitropyrene, where 1-acetamidopyren-6-ol, itself a potent mutagen, represents the major metabolic product. This difference in metabolism pathways may have implications for the genotoxicity of 3-nitrofluoranthene.