Modified spectrophotometer for multi-dimensional circular dichroism/fluorescence data acquisition in titration experiments: application to the pH and guanidine-HCI induced unfolding of apomyoglobin

In a previous paper (Ramsay and Eftink, Biophys. J. 66:516-523) we reported the development of a modified spectrophotometer that can make nearly simultaneous circular dichroism (CD) and fluorescence measurements. This arrangement allows multiple data sets to be collected during a single experiment, resulting in a saving of time and material, and improved correlation between the different types of measurements. The usefulness of the instrument was shown by thermal melting experiments on several different protein systems. This CD/fluorometer spectrophotometer has been further modified by interfacing with a syringe pump and a pH meter. This arrangement allows ligand, pH, and chemical denaturation titration experiments to be performed while monitoring changes in the sample's CD, absorbance, fluorescence, and light scattering properties. Our data acquisition program also has an ability to check whether the signals have approached equilibrium before the data is recorded. For performing pH titrations we have developed a procedure which uses the signal from a pH meter in a feedback circuit in order to collect data at evenly spaced pH intervals. We demonstrate the use of this instrument with studies of the unfolding of sperm whale apomyoglobin, as induced by acid pH and by the addition of guanidine-HCI.     

Effect of ruminal lactic acid-utilizing bacteria on adaptation of cattle to high-energy rations

Heifers, unadapted to a concentrate ration, were intraruminally inoculated (1 dose) with cultures of ruminal lactic acid-utilizing bacteria or with ruminal fluid from a steer adapted to a concentrate ration. Inoculation with cultures (1 L) of Selenomonas ruminantium or Megasphaera elsdenii did not produce better average daily weight gains or feed efficiency of heifers fed a high-energy ration for 21 days, if these values were compared with the performance of noninoculated heifers. Average daily weight gain and feed efficiency of heifers inoculated with 1 L of Peptococcus asaccharolyticus culture or with 1 L of adapted ruminal fluid and fed a high-energy ration for 21 days were better if these values were compared with the performance of noninoculated heifers.     

Steroid hormones in erysipelas

Deep neck infection has ominous implications if not detected and treated in an early stage. The anatomic relationships of head and neck spaces encourage spread of infection. Immediate hospitalization and constant monitoring of the patient after diagnosis are mandatory.     

Automated information systems in surgery and resuscitation]

Ten heat-acclimated females exercised seminude on a treadmill at 30% Vo2 max (M=152 W-m-2) under eight air temperatures (Ta) ranging from 30 degrees C to 52 degrees C. Each experiment involved 1 h of fixed and a 2nd h of progressively increasing water vapor pressure (Pw) with either air movement of 1 m-s-1 or still air. The equilibrium values of rectal temperature (Tre), mean skin temperature (Tsk),and heart rate (HR) reached in the 1st h were forced upwards in the 2nd h by the rising Pw. The critical Pw was defined by the Tre inflection point for each Ta. The loci of the critical Pw were used to delineate the thermal limits on the psychrometric chart and were used to derive the effective evaporative coefficient (Ke') applicable to the ambient capacity for evaporative cooling (Emax). The derived Ke' was 17.6 +/- 4.2 W-m-2 (mean +/- SD) for v0.6m-s-1. Isotherms constructed on the basis of the obtained Ké, Tsk, and sweating capacity were higher than the physiologically based Pw limits.     

Health and social costs of unemployment: Research and policy considerations.

Reviews recent studies of the social and private costs of unemployment. Although the experience of joblessness differs according to circumstances, prolonged unemployment is commonly a serious threat to health and the broad quality of life. These costs are borne not only by individual workers, but also by their families and communities. Research on unemployment has examined (1) associations between unemployment rate and indicators of strain such as psychiatric admissions and infant mortality, (2) ecologic studies of economic change, and (3) associations between unemployment and the demand for mental health services. The implications of this research for economic and social policy are discussed and contrasted with policy development premised on a benign view of unemployment. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The synergistic effect of excimer and low-pressure mercury lamps on the disinfection of flowing water

Microorganisms in flowing water were disinfected by UV radiation from two excimer (excited dimer) lamps (emitting at 172 and 222 nm) in combination with two low-pressure mercury lamps (emitting at 254 nm). Synergies were investigated among the three types of radiation in the treatment of water spiked in turn with Escherichia coli, Listeria innocua, Shewanella putrefaciens, and spores of Bacillus subtilis and Bacillus cereus. Synergy was demonstrated between radiations at 222 and 254 nm in the treatment of E. coli, L. innocua, and S. putrefaciens, but little or no synergy was observed in the treatment of B. subtilis and B. cereus. At maximum flow rates (60 liters/min), 5-log reductions in E. coli were achieved at 254 nm, although at 222 nm, less than 1-log reductions were observed. No bacterial kill was observed with 172-nm radiation alone, despite increasing exposure time by reducing flow rates to less than 3 liters/min.