The effectiveness of ampicillin, penicillin, streptomycin, and gentamicin against 20 strains of Listeria monocytogenes was studied in vitro. For all strains, the minimal bactericidal concentration (MBC) of both ampicillin and penicillin was much higher than the minimal inhibitory concentration (MIC). The MBC of both streptomycin and gentamicin was close to the MIC, but relatively high concentrations of these antibiotics were necessary to inhibit the growth of most of the strains of Listeria. The combination of penicillin plus streptomycin was synergistic against 19 of 20 strains and in the remaining strain produced enhanced killing (but of less magnitude than our criterion for synergism). Combinations of penicillin plus gentamicin, ampicillin plus streptomycin, and ampicillin plus gentaniicin produced enhanced killing against all strains tested. No antagonism was observed when ampicillin or penicillin was combined with streptomycin or gentamicin.
The purpose of this study was to identify the energy practices of low‐income households in Virginia and to assess the impact of high energy prices on their lives. A survey of 941 low‐income Virginia households revealed that household income, tenure type, and home structure type showed significant relationships with energy practices of these households. Results include the following: (1) households with the lowest incomes and renters tended to perceive more energy cost problems and (2) multifamily residents (e.g., in apartments or townhomes) were less likely to check for energy efficiency when buying a product that uses energy and less likely to try to find information on how to save energy compared to residents of single‐family homes and others (e.g., in mobile homes and other nontraditional homes). More research is needed on how to best assist these households with their energy burdens and to provide them with the information and motivation to help improve their situation.
The performance of phosphate-built, carbonate-built, and unbuilt liquid laundry detergents was evaluated with standard controlled tests to determine soil removal, soil deposition, and carbonate deposition in soft and hard water using home laundry appliances. Light reflectance data were analyzed using analysis of variance procedures. All three types of detergents performed better in soft water than in hard. The unbuilt liquids and phosphate-built powders were more effective in soil removal and whiteness retention than the carbonate-built products, and differences in results were magnified as the number of washings was increased. At present, unbuilt liquids are a practical and effective alternative to phosphate-built laundry detergents. THE PROBLEMA ban on the sale of phosphate-built detergents, first legislated in the 1970s, has been in effect in seven states (Indiana, Maryland, Michigan, Minnesota, New York, Vermont, and Wisconsin) as ~areii as the District of Columbia and parts of iliin®is and Ohio. In addition, legislation to prohibit the sale of detergents having more than 0.5% phosphorus became effective in Virginia and North Carolina on January 1, 1988. Manufacturers have voluntarily reduced the level of phosphate in detergents since 1970. As reported by Procter and Gamble, the level of phosphorus in all laundry detergents in 1970 averaged 11 percent, but by 1984 it had dropped to about 5 percent (Williams, 1984). However, it should be noted that the liquid products, which contain no phosphorus and were not available in 1970, had become popular by 1984 and were included in calculating the 1984 overall average. The phosphorus level in October 1986 of several national brands of granular detergents marketed in the area where tests were conducted is shown in Table 1 (page 254).Although many researchers have studied the effects of phosphate and nonphosphate builders on laundry performance, the methodology and detergent formulations have been so varied that generalizations for all laundry conditions are almost ir~p®ssibl~. Primary limitations of previous research fall into three categories: 1) length of time since the research was conducted and the rapid change in product formulations 2) water qualityseveral studies have been conducted with hard or distilled water, few with water classified as naturally soft; and 3) data collection
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