Comparison of the action spectra and relative DNA absorbance spectra of microorganisms: Information important for the determination of germicidal fluence (UV dose) in an ultraviolet disinfection of water

The action spectra of Bacillus subtilis spores (ATCC6633) and Salmonella typhimurium LT2 were characterized using physical radiometry for irradiance measurements and a multiple target model to interpret the inactivation kinetics. The observed action spectrum of B. subtilis spores deviated significantly from the relative absorbance spectrum of the DNA purified from the spores, but matched quite well with the relative absorbance spectrum of decoated spores. The action spectrum of B. subtilis spores determined in this study was statistically different from those reported in previous studies. On the other hand, the action spectrum of S. typhimurium bacteria matched quite well with the relative absorbance spectrum of DNA extracted from vegetative cells, except in the region below 240 nm. It is concluded that the common use of the relative DNA absorbance spectrum as a surrogate for the germicidal action spectrum can result in systematic errors when evaluating the performance of a polychromatic UV light reactors using bioassays. For example, if the weighted germicidal fluence (UV dose) calculated using the relative DNA absorbance spectrum as the germicidal weighting factor is found to be 40 mJ cm⁻² for a medium pressure lamp UV reactor, that calculated using the relative action spectrum of B. subtilis spores, as determined in this study, would be 66 mJ cm⁻².     

Investigation of Prolonged Drug Release from Matrix Formulations of Chitosan

A hydrocolloidal matrix system containing complexes of chitosan was investigated for preparation of sustained release tablets and examined in-vitro.

Theophylline tablets using chitosan as a sustained release base were evaluated. It was found that when chitosan is used in a concentration of more than 50% of tablet weight, an insoluble non-erosion type matrix was formed. Tablets prepared with a chitosan concentration of less than 33% were fast releasing.

Chitosan used in a concentration of about 10% acted as a disintegrant and the drug was dissolved within an hour.

Citric acid slowed down the release rates of chitosan based theophylline tablets. Theophylline tablets using carbomer-934P as a sustained release base were evaluated. Carbomer-934P in lower concentrations forms an erosion type matrix. In order to produce a twenty-four (24) hour sustained release tablet, more than 10% concentration of carbomer-934P is needed. Combination with chitosan and carbomer-934P produced slower releasing tablets.

A hydrocolloidal erosion type matrix was formulated using chitosan, carbomer-934Pand citric acid. Only 10% of chitosan was needed to prepare theophylline sustained release tablets in these mixtures.

The dose dumping potential of chitosan tablets due to rapid disintegration in alkaline media was eliminated by preparing hydrated erosion type matrix systems.     

Effect of roasting oil composition on the stability of roasted high-oleic peanuts

Off-flavor due to lipid degradation is an important factor in the shelf life of peanut products. The use of recently developed peanuts with high-oleic acid/linoleic acid (O/L) ratio has the potential to significantly extend the shelf life of roasted peanuts. To determine the full potential for shelf-life improvement of oil-roasted high-O/L peanuts, a study was conducted to examine the effects of roasting high-O/L peanuts (O/L=30) in high-O/L (O/L=23.2) or conventional (O/L=1.5) peanut oil. Peanuts were roasted at 177°C to Hunter L values of 49±1. Roasted peanuts were stored at 30°C for 20 wk. Samples were taken at regular intervals to determine PV, oxidative stability index (OSI), moisture content, and water activity. The O/L ratio of high-O/L roasted peanuts was 27.9 vs. 13.6 for the conventional oil-roasted peanuts. After 20 wk of storage, PV of conventional oil-roasted peanuts was 10.8 compared to 5.3 for the high-O/L-roasted peanuts. OSI values were 88.5 and 52.4 immediately after roasting for the high-O/L-roasted vs. conventional oil-roasted peanuts. OSI for both decreased, but differences remained similar throughout the storage period. Shelf life of high-O/L peanuts decreased when roasted in conventional O/L-peanut oil vs. high-O/L peanut oil.     

A smooth-walled spline-profile horn as an alternative to the corrugated horn for wide band millimeter-wave applications

At millimeter-wave frequencies, corrugated horns can be difficult and expensive to manufacture. As an alternative we present here the results of a theoretical and measurement study of a smooth-walled spline-profile horn for specific application in the 80-120 GHz band. While about 50% longer than its corrugated counterpart, the smooth-walled horn is shown to give improved performance across the band as well as being much easier to manufacture.     

Options for diabetic patients with chronic heel ulcers

Which are the determinants of return to work in middle aged myocardial infarction patients? This question was analysed by means of a follow-up study on men between 1986 and 1992 (group 1: n = 64, age = 46.6 (+/- 5.4), 5-6 years follow-up; group 2: n = 36, age = 51.2 (+/- 7.5), 2 years follow up), all of whom underwent a cardiac rehabilitation program in our hospital. Our aim was to determine the predictive power of social and psychological as compared to cardiologic factors. These factors were operating under two relevant conditions: 1. relative social homogeneity of the samples; 2. rehabilitation including qualified cardiologic diagnostic and an interdisciplinary therapeutic program. As a result we found age--at the same time a biologic and a social variable--to be the best independent predictor in logistic regression as in discriminant analysis. Age was followed by hopelessness in the year before MI, ST segment depression in physical stress test and, with restriction, marital status. Thus our study points to three factors limiting employment status: age as a biological and social limit for achievement, ST segment depression as a coronary and ongoing hopelessness as a psychological limit, with a social background of living alone in some cases. It is important for cardiac rehabilitation to take into account not only biological but also social and psychological limits of work capacity. Comprehensive care tries to modify these limits but cannot remove them.     

Electromyography of the diaphragm in neuromuscular disease

We compared the diaphragmatic electromyographic (EMG) recordings from 32 patients with known neuromuscular disease and respiratory symptoms (23 neuropathies, 9 myopathies) to recordings from 23 normal subjects. Turns analysis of 219-ms sections, or epochs, of the EMG demonstrated a significant overlap between diagnostic groups, although some epochs from neuromuscular patients were significantly different from normal. Empirical rules were derived to infer neuropathic and myopathic involvement of the diaphragmatic EMG.     

Ventile, incompressible cushions

The idea and initial trials of dry fluid cushioning are described. Better body support, comfort and ventility (ventilation permeability), are among the advantages expected to result from this development. Some design details and possible applications are discussed.     

The chloride balance in a fertiliser experiment on sandy soil

One-third of the chloride, given as sodium chloride to kale and barley in successive years, was recovered in the harvested crops, or in ryegrass grown the following year. Crops on ground not given salt removed amounts of chloride comparable with those in the annual rainfall, so drainage losses under these crops were small. Improved analytical methods for chloride in soils and plants are described, using colorimetry and potentiometer titration's.     

Psychosocial factors affecting the employment of former vocational rehabilitation clients.

Analyzed questionnaires completed by 211 former vocational rehabilitation (VR) clients (aged 15–61 yrs) 2 yrs after case closure for a clarification of the psychosocial factors that affect vocational adjustment. Questionnaires assessed employment status and problems, sources of income/financial status, health, and job satisfaction (for employed Ss only). WAIS Full Scale IQs were available for 195 Ss, and 120 Ss had completed the 16PF—Form E. Results show that the primary criteria of vocational adjustment (employment, job satisfaction, and persistence in looking for work) were associated with better self-appraised physical and mental health, greater perceived family support in seeking employment, more optimism about employment prospects, and attribution of the problem source to the environment. These variables suggest useful points for intervention by VR practitioners. (5 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)