Collaborative Study of the α-Toxin Method for Estimating Population Levels of Clostridium perfringens in Food

1974 ◽  
Vol 57 (1) ◽  
pp. 91-94
Author(s):  
Stanley M Harmon ◽  
Donald A Kautter

Abstract A microbiological method for estimating population levels of Clostridium perfringens in food, based on the presence of α-toxin, was studied collaboratively in 15 laboratories. The collaborators extracted α-toxin from identical samples of roast beef and quantitatively determined it in hemolysin indicator plates. The titer of a-toxin found was utilized to estimate the population level of C. perfringens in the roast beef by correlating the titer of α-toxin present in the beef with experimental data on the relationship of viable counts and α-toxin production supplied to the collaborators. Forty-five of 52 samples examined were found to contain α-toxin at a dilution of 1+63 to 1+127 as measured in hemolysin indicator plates. The remainder had α-toxin titers one 2-fold dilution higher or lower. The estimated population levels obtained by the various laboratories ranged from 7.3 α 107 to 17.8 α 107/g. The standard deviation among replicate determinations within collaborators was 3.5 × 107/g. These results indicate that the precision of the α-toxin method makes it useful for estimating the maximum population of C. perfringens in a suspect outbreak food.

2018 ◽  
Vol 616 ◽  
pp. A76 ◽  
Author(s):  
Marko Sestovic ◽  
Brice-Olivier Demory ◽  
Didier Queloz

Context. As of today, hundreds of hot Jupiters have been found, yet the inflated radii of a large fraction of them remain unexplained. A number of mechanisms have been proposed to explain these anomalous radii, however most of these can only work under certain conditions and may not be sufficient to explain the most extreme cases. It is still unclear whether a single mechanism can sufficiently explain the entire distribution of radii, or whether a combination of these mechanisms is needed. Aims. We seek to understand the relationship of radius with stellar irradiation and mass and to find the range of masses over which hot Jupiters are inflated. We also aim to find the intrinsic physical scatter in their radii, caused by unobservable parameters, and to constrain the fraction of hot Jupiters that exhibit inflation. Methods. By constructing a hierarchical Bayesian model, we inferred the probabilistic relation between planet radius, mass, and incident flux for a sample of 286 gas giants. We separately incorporated the observational uncertainties of the data and the intrinsic physical scatter in the population. This allowed us to treat the intrinsic physical scatter in radii, due to latent parameters such as the heavy element fraction, as a parameter to be inferred. Results. We find that the planetary mass plays a key role in the inflation extent and that planets in the range ~0.37−0.98  MJ show the most inflated radii. At higher masses, the radius response to incident flux begins to decrease. Below a threshold of 0.37 ± 0.03  MJ we find that giant exoplanets as a population are unable to maintain inflated radii ≿1.4  RJ but instead exhibit smaller sizes as the incident flux is increased beyond 106 W m−2. We also find that below 1  MJ, there is a cut-off point at high incident flux beyond which we find no more inflated planets, and that this cut-off point decreases as the mass decreases. At incident fluxes higher than ~1.6 × 106 W m−2 and in a mass range 0.37−0.98  MJ, we find no evidence for a population of non-inflated hot Jupiters. Our study sheds a fresh light on one of the key questions in the field and demonstrates the importance of population-level analysis to grasp the underlying properties of exoplanets.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 16-17
Author(s):  
Miguel Gonzalez Velez ◽  
Carolyn Mead-Harvey ◽  
Heidi E. Kosiorek ◽  
Yael Kusne ◽  
Leyla Bojanini ◽  
...  

Introduction: Serum folate (SF), vitamin B12 (B12), and iron deficiency (def) are common causes of nutritional anemias (NA). These deficiencies are usually multifactorial, with nutritional and non-nutritional causes playing a role. SF, B12, and iron levels are usually ordered in the setting of anemia, and malnutrition with or without neurologic symptoms. Clinical evidence suggests that these def have a strong dietary component and socioeconomic status (SES). The relationship of NA and area-based SES in the US has not been studied. We aimed to determine the relationship of SES with the prevalence of NA. Methods: We performed a cross-sectional analysis of adult patients with SF, B12 and iron levels at Mayo Clinic Arizona and Florida between 2010 and 2018. Race was classified using the NIH criteria. Normal laboratory values were determined according to our lab reference and the US NHANES III. SF levels (mcg/Lt) were defined as deficient <4, normal ≥4.0, and excess ≥20. B12 levels (ng/L) as deficient <150, borderline 150-400, normal >400-900, and excess ≥900. Iron def was determined by ferritin levels (mcg/L) as low <24, normal 24-336, elevated >336 for men, low <11, normal 11-307, elevated >307 for women. Area-Level SES indicators: Median Household income (MHI), unemployment rate (UR), median gross rent month (MGRM), % uninsured, median house value (MHV), % high school; were geocoded by zip code using the 2014 American Community Survey. Demographics and clinical variables were compared between groups by chi-square test for frequency data or Kruskal Wallis rank-sum test for continuous variables. Results: 202,046 samples from 128,084 patients were analyzed. In the sample-level analysis, there were statistically significant associations between SES and SF def; all SES indicators except UR for B12 def; and no differences for iron def, except % uninsured (Table 1). There was no statistically significant interaction between race and SES for SF def and iron def. Race was a statistically significant modifier between B12 def and MHI (p<0.001), % uninsured (p=0.002), and MHV (p=0.007). Asian and Other race had an increase in odds of B12 def with increasing MHI (Asian OR=1.11 , Other OR=1.18); white race had a decrease in odds of B12 def with increasing MHI (OR=0.95 for a $10,000 increase in MHI). Conclusions: We show significant relationships between SES and NA in the US. Differences were observed between SF def and all the SES indicators without race interactions. There were significant interactions between B12 def, race and SES for pts of White, Asian and Other race. There were no differences between SES and race for iron def. These relationships confirm that NA are related to area-level SES and other social determinants of health. Research regarding the causes of these disparities on a population level are needed. Disclosures No relevant conflicts of interest to declare.


2015 ◽  
Vol 760 ◽  
pp. 469-474 ◽  
Author(s):  
Aurelian Vlase ◽  
Ovidiu Blăjină ◽  
Marius Iacob

This paper studies the cutting moment at drilling of the stainless steel X15CrNiSi20-12. The structure of the cutting moment relation was modified with respect to the relation available in the technical literature for common steels. The tool speed was included in the calculus relation. The experimental data and their subsequent processing represent the original contributions of the authors to the estimation of polytropic exponents and to the assessment in terms of structure of the calculus relation of the cutting moment. The paper also contains graphs for the variation of the cutting moment with parameters of the cutting technology. The graphs are drawn based on the analytic relationship of the cutting moment, obtained in the paper, using the mathematical softwareMaple. The results presented in this study can be taken into consideration in the educational studies and in the theoretical technical research. Also, they can be readily implemented in the manufacturing activity. Our further studies aim these problems for another steels classes.


1975 ◽  
Vol 42 (4) ◽  
pp. 805-808 ◽  
Author(s):  
R. P. Parker ◽  
V. H. Neubert

In developing the relationship of the normal mode solution for a vibrating rod to the pyrotechnic shock problem, a detailed analysis is presented using the Timoshenko theory to obtain the transient lateral response of a cylindrical rod with free ends to a short duration half sine pulse of either moment or shear applied to one end. Two different series solutions are used and the rates of convergence are compared near the boundary. Results are compared with experimental data.


2014 ◽  
Vol 881-883 ◽  
pp. 1638-1641
Author(s):  
Xian Long Sun ◽  
Er Xin Gao ◽  
Hong Fen Zhang ◽  
Qiang Wang ◽  
Li Juan Li

Based on the geological and the experimental data of the13#coal seam of Sun-Cun Coal Mine, the relationship curve between the geothermal heat in Sun-Cun coal mine and experimental wind speed has been fit out.According this and the laboratory experiments,the relational expression between the quantity of CO2 produced in the period of spontaneous combustion and the wind speed in the coal mine has been developed. The research results show that when the wind speed exceeds 2m/s,the quantity of CO2 produced has a sharp rising tendency.


1976 ◽  
Vol 59 (3) ◽  
pp. 606-612
Author(s):  
Stanley M Harmon

Abstract A collaborative study was conducted in 10 laboratories to evaluate the performance of a new method for the enumeration of vegetative cells of Clostridium perfringens in foods. Results obtained by the new method were compared with results from the official first action method, 46.049–46.053. Per cent recoveries of 4 C. perfringens strains from inoculated roast beef samples were higher and more consistent in tryptose-sulfite-cycloserine (TSC) agar with or without added egg yolk than in sulfitepolymyxin-sulfadiazine (SPS) agar, specified in the official first action method. The confirmatory technique utilized in the new method was also found to be more reliable than the technique described in the official first action method. Based on the collaborative results, the new method with TSC agar for enumeration and a modified motility-nitrate medium together with a lactose-gelatin medium for confirmation of C. perfringens has been adopted as official first action to replace 46.049–46.053.


1987 ◽  
Vol 64 (1) ◽  
pp. 44-46 ◽  
Author(s):  
Robert A. Hicks ◽  
Eliot R. Garcia

30 subjects kept daily diaries of sleep-duration and stress levels for 4 mo. From these data, it was determined that during periods of high stress, sleep was reduced by about one standard deviation while during periods of low stress, sleep increased by about one-half a standard deviation. The relationship of these results to the relevant sleep-stress literature was briefly discussed.


2020 ◽  
Vol 9 (2) ◽  
pp. 35
Author(s):  
Yendraliza Yendraliza ◽  
Muhamad Rodiallah ◽  
Zumarni Zumarni

This study was conducted to determine the relationship of birth weight of calves, sex ratio of the calves, and the age of the dam to the length of pregnancy in buffaloes resulting from artificial insemination in Kampar District. The method used in this research is the descriptive method by displaying the average and standard deviation. The total number of buffaloes that were artificially inseminated in 2018 and gave birth in 2019 was 21 buffalo-cows. Data were analyzed with the Pearson Product Moment (PPM) correlation. The parameters measured in this study were the length of pregnancy, calf birth weight, calf sex ratio, and dam’s age. The results showed a positive correlation between the birth weight of the calves, sex ratio of the calves, and the age of the dam to the length of pregnancy of 1.4%, with an average length of pregnancy, calf birth weight, and sex ratio of 351.81 days, 27.38 kg, and 1: 1 respectively.


2014 ◽  
Vol 657 ◽  
pp. 3-7
Author(s):  
Ovidiu Blăjină ◽  
Vlad Darie ◽  
Aurelian Vlase ◽  
Marius Iacob

This paper studies the cutting force at drilling of the stainless steel X15CrNiSi20-12. The structure of the cutting force relation was modified with respect to the relation available in the technical literature for common steels. The tool speed was included in the calculus relation. The experimental data and their subsequent processing represent the original contributions of the authors to the estimation of polytropic exponents and to the assessment in terms of structure of the calculus relation of the cutting force. The paper also contains graphs for the variation of the cutting force with parameters of the cutting technology. The graphs are drawn based on the analytic relationship of the cutting force, obtained in the paper, using the mathematical softwareMaple. The results presented in this study can be taken into consideration in the educational studies and in the theoretical technical research. Also, they can be readily implemented in the manufacturing activity. Our further studies aim these problems for another steels classes.


2014 ◽  
Vol 962-965 ◽  
pp. 731-735
Author(s):  
Bi Jun Luo ◽  
Dan Wu ◽  
Hai Hong Wu ◽  
Tao Wang ◽  
Xi Ping Huang

Crystallization kinetics experiment of calcium sulfate dehydrates, which is prepared by bittern under 30oC and different stirring speed conditions, is carried out. According to the results of the experimental data, the relationship of nucleus particle-number density n0 and crystal growth rate G with the residence time, temperature and the stirring speed is summarized. Also, the crystallization kinetics formula under 30oC and different stirring speed is given.


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