Avoiding Interferences from Good's Buffers: A Contiguous Series of Noncomplexing Tertiary Amine Buffers Covering the Entire Range of pH 3–11

1997 ◽  
Vol 253 (1) ◽  
pp. 50-56 ◽  
Author(s):  
Qiuyue Yu ◽  
Ashoka Kandegedara ◽  
Yanping Xu ◽  
D.B. Rorabacher
1989 ◽  
Vol 28 (2) ◽  
pp. 169-170 ◽  
Author(s):  
Fengjiang Wang ◽  
Lawrence M. Sayre
Keyword(s):  

2020 ◽  
pp. 40-45
Author(s):  
Nadezhda O. Vzduleva ◽  
Valery B. Gitlin

The problems of ensuring the stability of the temperature of the chromatographic experiment carried out using a serial gas chromatograph LGH-3000 are considered. Limiting the permissible heating rate of the chromatograph thermostats does not allow a quick transition to the new conditions of the chromatographic experiment in accordance with the requirements of the technical conditions. The processes of heating and cooling the thermostat are analyzed. It is shown that the ratio of the duration of the interval equal to the sum of the durations of the heating and cooling intervals to the duration of the heating interval is inversely proportional to the temperature of the chromatographic experiment. Based on this situation, an empirical algorithm is proposed for heating the thermostat to a given temperature, which made it possible to reduce the time it takes to reach a given temperature in the entire range of operating temperatures.


1970 ◽  
Vol 63 (2) ◽  
pp. 225-241 ◽  
Author(s):  
B. D. Reeves ◽  
M. L. A. de Souza ◽  
I. E. Thompson ◽  
E. Diczfalusy

ABSTRACT An improved method for the assay of plasma progesterone by competitive protein binding is described. The improvement is based upon rigorous control of the variables, the compensation for and standardisation of interfering factors inherent in the method and the use of a human corticosteroid binding globulin, that meets the requirements for sensitivity at levels of 1.0 ng of progesterone and below. The assessment of the reliability of the individual steps in the method as well as that of the complete method is presented. The sensitivity of the method is around 0.2 ng progesterone per ml plasma. Accuracy was measured by adding progesterone in amounts ranging from 0.0 to 1.0 ng to 1.0 ml plasma. There was a linear relationship between the progesterone added and recovered throughout the entire range of values, with a coefficient of correlation (r) of 0.94. Of 52 related steroids tested, none was found which would remain associated with progesterone following extraction and purification and which would also compete with progesterone for binding sites.


2008 ◽  
Vol 59 (1) ◽  
pp. 45-48
Author(s):  
Oana Ciocirlan ◽  
Olga Iulian

This paper reports the viscosities measurements for the binary system dimethyl sulfoxide + 1,4-dimethylbenzene over the entire range of mole fraction at 298.15, 303.15, 313.15 and 323.15 K and atmospheric pressure. The experimental viscosities were correlated with the equations of Grunberg-Nissan, Katti-Chaudhri, Hind, Soliman and McAllister; the adjustable binary parameters have been obtained. The excess Gibbs energy of activation of viscous flow (G*E) has been calculated from the experimental measurements and the results were fitted to Redlich-Kister polynomial equation. The obtained negative excess Gibbs free energy of activation and negative Grunberg-Nissan interaction parameter are discussed in structural and interactional terms.


2020 ◽  
Vol 16 ◽  
Author(s):  
Bathinapatla Ayyappa ◽  
Suvardhan Kanchi ◽  
Myalowenkosi I. Sabela ◽  
Krishna Bisetty

BACKGROUND: Sucralose is a high intensity artificial sweetener sucralose and chemically known as 1,6-dichloro-1,6-dideoxy-β-D-fructofuranosyl-4-chloro-4-deoxy-α-D-galactopyranoside. It is used as a sweetener and flavour enhancer in foods and beverages. Due to its high stability at wider temperatures and pH, made its applicability in various food products throughout the world. As per Joint FAO/WHO Expert Group on Food Additives (JECFA) in 1990, the daily intake of sucralose is 0-15 mg/kg body weight. The literature reports suggest that sucralose has a possible health threat due to the presence of chlorine groups, thereby leading to the several illnesses. The growing interest on the use of SUC in the foods, makes it necessary in developing a fast, reliable, cost effective and reproducible analytical method to determine SUC in food samples. The detection of sucralose and other carbohydrates like fructose, glucose and sucrose is a challenging task owing to its: (i) unavailability of the charged functions and (ii) lack of absorption of strong chromophoric nature in the UV region. Therefore, separation of non-absorbing neutral molecules needs a careful procedure with the suitable electrolyte systems. METHODOLOGY: An indirect UV detection capillary electrophoretic method is described for the separation of sucralose in different food samples. It was achieved by nucleophile substitution (SN2) in the presence of amine as background electrolytes. The morpholine buffer showed good buffering capacity in terms of migration time (< 8.0 min) and baseline stability when compared to other amine buffers (ethylamine, piperidine, triethylamine). The analytical applications of proposed method showed by recovery percentages of sucralose in real and spiked samples on intra and inter-day basis at optimum experimental conditions of 0.2 M buffer concentration and pH 12.0 at 230 nm UV detection. RESULTS: The selection of BGE, UV detection wavelength, buffer concentration, buffer pH, cassette temperature and applied voltage were optimized to enhance the sensitivity and selectivity of the separation method. Recoveries obtained were ranging from 96.87 to 98.82 % for real samples and 94.45 to 98.06 % for spiked samples respectively. Linearity was studied in the range of 2-10 mM, and showed a correlation coefficients of 0.9942 with LOD and LOQ found to be 0.3804 mg L-1 and 1.5215 mg L-1 with % RSD (n = 5) ± 1.27 and 1.19 % with respect to migration time and peak area. Furthermore, to better understand the separation of sucralose with amine buffers were investigated computationally using HOMO-LUMO calculations. The obtained results showed that the band gap decreases in the presence of amine moiety irrespective of its nature. CONCLUSION: In the study, novel background electrolytic system was successfully applied to separate sucralose using indirect UV detector with capillary electrophoresis. The FT-IR results confirmed that the interaction of sucralose with different amine buffers to better understand the separation chemistry behind sucralose and amine complexes. Moreover, computational results indicate that the direction of charge transfer from the amine functionality to the glucofuranosyl ring in each amine derivative of sucralose confirms the strong interaction between sucralose and amines, which led in the baseline separation of sucralose in different food samples.


Author(s):  
Carrie Figdor

Many people accept that chimpanzees, dolphins, and some other animals can think and feel. But these cases are just the tip of a growing iceberg. If biologists are right, fruit flies and plants make decisions, worms and honeybees can be trained, bacteria communicate linguistically, and neurons have preferences. Just how far does cognition go? This book is the first to critically consider this question from the perspective of the entire range of new ascriptions of psychological capacities throughout biology. It is also the first to consider the role of mathematical models and other quantitative forms of evidence in prompting and supporting the new ascriptions. It defends a default literal interpretation of psychological terms across biological domains. It also considers the implications of the literal view for efforts to explain the mind’s place in nature and for traditional ways of distinguishing the superior moral status of humans relative to other living beings.


RSC Advances ◽  
2021 ◽  
Vol 11 (41) ◽  
pp. 25477-25483
Author(s):  
Qianya Cheng ◽  
Tong Zhou ◽  
Qing Xia ◽  
Xiulian Lu ◽  
Heng Xu ◽  
...  

The tertiary amine in F4b facilitates the Fenton-like reaction to generate toxic ˙OH which induces apoptosis through CDK-2 inactivation.


Author(s):  
Tahir Ahmed Hassen ◽  
Catherine Chojenta ◽  
Nicholas Egan ◽  
Deborah Loxton

This study aimed to evaluate the association of the five-minute Apgar score and neurodevelopmental outcomes in children by taking the entire range of Apgar scores into account. Data from the Australian Longitudinal Study of Women’s Health (ALSWH) and Mothers and their Children’s Health (MatCH) study were linked with Australian state-based Perinatal Data Collections (PDCs) for 809 children aged 8−66 months old. Generalized estimating equations were used to model the association between the five-minute Apgar scores and neurodevelopmental outcomes, using STATA software V.15. Of the 809 children, 614 (75.3%) had a five-minute Apgar score of 9, and 130 (16.1%) had an Apgar score of 10. Approximately 1.9% and 6.2% had Apgar scores of 0−6 and 7−8, respectively. Sixty-nine (8.5%) of children had a neurodevelopmental delay. Children with an Apgar score of 0−6 (AOR = 5.7; 95% CI: 1.2, 27.8) and 7−8 (AOR = 4.1; 95% CI: 1.2, 14.1) had greater odds of gross-motor neurodevelopment delay compared to children with an Apgar score of 10. Further, when continuously modelled, the five-minute Apgar score was inversely associated with neurodevelopmental delay (AOR = 0.75; 95% CI: 0.60, 0.93). Five-minute Apgar score was independently and inversely associated with a neurodevelopmental delay, and the risks were higher even within an Apgar score of 7−8. Hence, the Apgar score may need to be taken into account when evaluating neurodevelopmental outcomes in children.


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