Author
Robert W. Zumwalt
Bio: Robert W. Zumwalt is an academic researcher from University of Missouri. The author has contributed to research in topics: Gas chromatography & Amino acid. The author has an hindex of 22, co-authored 37 publications receiving 1883 citations.
Papers
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TL;DR: The use of ultrasonication to remove dissolved air while pulling a vaccumm on the sample solution prior to hydrolysis assured a good recovery for methionine and cystine as discussed by the authors.
365 citations
171 citations
TL;DR: The development of a gas—liquid chromatographic (GLC) method for the quantitative analysis of amino acids in complex biological substances, specifically blood plasma and urine, has been achieved and data obtained were in excellent agreement with results by classical ion exchange.
121 citations
TL;DR: The gas-liquid chromatographic separation of the N-trimethylsilyl TMS esters of the twenty protein amino acids was achieved after evaluation of a number of combinations of siloxane liquid phases and reaction conditions were investigated for the quantitative silylation.
119 citations
118 citations
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TL;DR: The system described here gives a direct and precise method for determining DNA base composition by reversed-phase high-performance liquid chromatography (HPLC).
Abstract: DNA base composition was determined by reversed-phase high-performance liquid chromatography (HPLC). DNA was hydrolysed into nucleosides with nuclease P1 and bacterial alkaline phosphatase. The mixture of nucleosides was applied to HPLC without any further purification. One determination by chromatography needed 2 μg of hydrolysed nucleosides and took only 8 min. The relative standard error of nucleoside analysis was less than 1%. The system described here gives a direct and precise method for determining DNA base composition.
2,468 citations
Book•
26 May 2009
TL;DR: In this article, the authors present a nonparametric statistical procedure for the test of sample normality in the context of practice questions, and compare the results of two related tests: the Mann-Whitney U -Test and the Fisher Exact Test.
Abstract: Preface. 1 Nonparametric Statistics: An Introduction. 1.1 Objectives. 1.2 Introduction. 1.3 The Nonparametric Statistical Procedures Presented in this Book. 1.4 Ranking Data. 1.5 Ranking Data with Tied Values. 1.6 Counts of Observations. 1.7 Summary. 1.8 Practice Questions. 1.9 Solutions to Practice Questions. 2 Testing Data for Normality. 2.1 Objectives. 2.2 Introduction. 2.3 Describing Data and the Normal Distribution. 2.4 Computing and Testing Kurtosis and Skewness for Sample Normality. 2.5 The Kolmogorov-Smirnov One-Sample Test. 2.6 Summary. 2.7 Practice Questions. 2.8 Solutions to Practice Questions. 3 Comparing Two Related Samples: The Wilcoxon Signed Ranks Test. 3.1 Objectives. 3.2 Introduction. 3.3 Computing the Wilcoxon Signed Ranks Test Statistic. 3.4 Examples from the Literature. 3.5 Summary. 3.6 Practice Questions. 3.7 Solutions to Practice Questions. 4 Comparing Two Unrelated Samples: The Mann-Whitney U -Test. 4.1 Objectives. 4.2 Introduction. 4.3 Computing the Mann-Whitney U -Test Statistic. 4.4 Examples from the Literature. 4.5 Summary. 4.6 Practice Questions. 4.7 Solutions to Practice Questions. 5 Comparing More Than Two Related Samples: The Friedman Test. 5.1 Objectives. 5.2 Introduction. 5.3 Computing the Friedman Test Statistic. 5.4 Examples from the Literature. 5.5 Summary. 5.6 Practice Questions. 5.7 Solutions to Practice Questions. 6 Comparing More than Two Unrelated Samples: The Kruskal-Wallis H -Test. 6.1 Objectives. 6.2 Introduction. 6.3 Computing the Kruskal-Wallis H -Test Statistic. 6.4 Examples from the Literature. 6.5 Summary. 6.6 Practice Questions. 6.7 Solutions to Practice Questions. 7 Comparing Variables of Ordinal or Dichotomous Scales: Spearman Rank-Order, Point-Biserial, and Biserial Correlations. 7.1 Objectives. 7.2 Introduction. 7.3 The Correlation Coefficient. 7.4 Computing the Spearman Rank-Order Correlation Coefficient. 7.5 Computing the Point-Biserial and Biserial Correlation Coefficients. 7.6 Examples from the Literature. 7.7 Summary. 7.8 Practice Questions. 7.9 Solutions to Practice Questions. 8 Tests for Nominal Scale Data: Chi-Square and Fisher Exact Test. 8.1 Objectives. 8.2 Introduction. 8.3 The Chi-Square Goodness-of-Fit Test. 8.4 The Chi-Square Test for Independence. 8.5 The Fisher Exact Test. 8.6 Examples from the Literature. 8.7 Summary. 8.8 Practice Questions. 8.9 Solutions to Practice Questions. 9 Test For Randomness: The Runs Test. 9.1 Objectives. 9.2 Introduction. 9.3 The Runs Test for Randomness. 9.4 Examples from the Literature. 9.5 Summary. 9.6 Practice Questions. 9.7 Solutions to Practice Questions. Appendix A: SPSS at a Glance. A.1 Introduction. A.2 Opening SPSS. A.3 Inputting Data. A.4 Analyzing Data. A.5 The SPSS Output. Appendix B: Tables of Critical Values. Table B.1: The Normal Distribution. Table B.2: The Chi-Square Distribution. Table B.3: Critical Values for the Wilcoxon Signed Ranks Test Statistics, T . Table B.4: Critical Values for the Mann-Whitney U -Test Statistic. Table B.5: Critical Values for the Friedman Test Statistic, F r . Table B.6: The Critical Values for the Kruskal-Wallis H -Test Statistic. Table B.7: Critical Values for the Spearman Rank-Order Correlation Coefficient, r s . Table B.8: Critical Values for the Pearson Product-Moment Correlation Coefficient, r. Table B.9: Factorials. Table B.10: Critical Values for the Runs Test for Randomness. Bibliography. Index.
1,182 citations
TL;DR: Observations indicate that PrPC is anchored to the cell surface by the glycolipid, which is derived from PrPSc by limited proteolysis at the amino terminus.
1,109 citations
TL;DR: A gas chromatographic procedure has been developed for the quantitative analysis of submicrogram amounts of the phenylthiohydantoins of all the amino acids except arginine, divided into three groups according to their volatility and need for derivatization (trimethylsilylation).
608 citations
TL;DR: In this article, 17 fatty acids were observed with α-Linolenic acid (44.57%) having the highest value followed by heneicosanoic (14.41%), g-linolenic (0.20%), palmiteic ( 0.17%), and capric acid (0.,07%), while total polyphenols were 2.02%.
Abstract: calcium (3.65%), phoshorus (0.3%), magnesium (0.5%), potassium (1.5%), sodium (0.164%), sulphur (0.63%), zinc (13.03 mg/kg), copper (8.25%), manganese (86.8 mg/kg), iron (490 mg/kg) and selenium (363 mg/kg). 17 fatty acids were observed with α-Linolenic acid (44.57%) having the highest value followed by heneicosanoic (14.41%), g-linolenic (0.20%) palmiteic (0.17%) and capric acid (0.07%). Vitamin E had the highest concentration of 77 mg/100 g than beta-carotene, which had 18.5 mg/100 g in the dried leaves. The fiber content was neutral detergent fibre (NDF) (11.4%), acid detergent fibre (ADF) (8.49%), acid detergent lignin (ADL) (1.8%) and (acid detergent cellulose (ADC) (4.01%). The condensed tannins had a value of 3.2%, while total polyphenols were 2.02%. The values of amino acids, fatty acids, minerals and vitamin profiles reflect a desirable nutritional balance.
584 citations