scholarly journals XXXIII.—I. On the Estimation of Carbon in Organic Substances by the Kjeldahl Method. II. Its Application to the Analysis of Potable Waters

1895 ◽  
Vol 37 (4) ◽  
pp. 743-757
Author(s):  
Charles Hunter Stewart
Keyword(s):  
Accurate Method ◽  
Great Accuracy ◽  
Organic Substances ◽  
Applied Chemistry ◽  
Carbon And Nitrogen ◽  
Kjeldahl Method ◽  
The Will ◽  
Time Required

An easy and yet accurate method of determining carbon and nitrogen in organic substances has long been a desideratum, especially among those engaged in the application of chemistry to biological, hygienic, and agricultural questions. For the determination of nitrogen the method of Dumas, with its numerous modifications, is still the only one applicable in all cases, but the time required for it, and the manipulative dexterity necessary, has prevented its wide application for the above-named purposes. The method of Will and Varrentrap, though less generally applicable, is easier, and, until the publication of Kjeldahl's method, was most frequently used in applied chemistry. Kjeldahl claims for his method the same applicability and as great accuracy as the Will and Varrentrap method, with the added advantage of greater ease in working.

Application of Microwave Energy for Indirect Determination of Asphalt Total Polarity and Sulfur and Sulfide Content

1998 ◽  
Vol 1638 (1) ◽  
pp. 3-11 ◽  
Author(s):  
S. W. Bishara ◽  
Donna Mahoney
Keyword(s):  
Accurate Method ◽  
Heating Time ◽  
Time Range ◽  
Target Temperature ◽  
Dielectric Heating ◽  
Indirect Determination ◽  
Sulfide Content ◽  
Time Required ◽  
Characterization Test

A simple, inexpensive, and rapid—yet accurate—method is presented for the indirect determination of relative total polarity and sulfur and sulfide content of asphalt. For a given asphalt, the three parameters can be calculated from one measurement on a scientific microwave instrument. Using the eight Strategic Highway Research Program core asphalts, the dielectric heating time required for 10-g asphalt to reach a target temperature of 150°C was measured: AAD-1 took 10 min, whereas AAM-1 took 111.5 min. Because of this wide time range covered by the eight asphalts, the dielectric heating time may serve as a characterization test. The dielectric heating time correlates perfectly, r2 = .998 or 1.00, with total polarity of the four core asphalts for which total polarity has previously been determined by others. The curve equation was then used to calculate total polarity of the other four core asphalts, and may be used for any given asphalt once its dielectric heating time to reach a target temperature is measured. For the seven core asphalts with a nickel to vanadium ratio (Ni/V) > 1, the dielectric heating time correlates perfectly ( r2 = 1.00) with the sulfur content previously determined by others. For AAG-1, ABM-1, and ABD-1 (all have Ni/V < 1), a separate equation applies, also with r2 = 1.00. Sulfide content, previously determined by others, for the seven core asphalts with Ni/V > 1 correlates perfectly ( r2 = 1.00) with dielectric heating time. No separate equation could be derived for asphalts with Ni/V < 1 because only sulfide content of AAG-1 was known. For a given asphalt, sulfur and sulfide content can be calculated from the corresponding equation once the dielectric heating time is measured. The proposed method has a reasonable repeatability and bias for the three determined parameters.

scholarly journals Overcoming Fluctuation and Leakage Problems in the Quantification of Intracellular 2-Oxoglutarate Levels in Escherichia coli

2011 ◽  
Vol 77 (19) ◽  
pp. 6763-6771 ◽  
Author(s):  
Dalai Yan ◽  
Peter Lenz ◽  
Terence Hwa
Keyword(s):  
Escherichia Coli ◽  
Nitrogen Metabolism ◽  
Accurate Method ◽  
Reversed Phase ◽  
Carbon Substrate ◽  
Content Type ◽  
Carbon And Nitrogen ◽  
Liquid Chromatography Separation ◽  
Glutamate Biosynthesis

ABSTRACT2-Oxoglutarate is located at the junction between central carbon and nitrogen metabolism, serving as an intermediate for both. In nitrogen metabolism, 2-oxoglutarate acts as both a carbon skeletal carrier and an effector molecule. There have been only sporadic reports of its internal concentrations. Here we describe a sensitive and accurate method for determination of the 2-oxoglutarate pool concentration inEscherichia coli. The detection was based on fluorescence derivatization followed by reversed-phase high-pressure liquid chromatography separation. Two alternative cell sampling strategies, both of which were based on a fast filtration protocol, were sequentially developed to overcome both its fast metabolism and contamination from 2-oxoglutarate that leaks into the medium. We observed rapid changes in the 2-oxoglutarate pool concentration upon sudden depletion of nutrients: decreasing upon carbon depletion and increasing upon nitrogen depletion. The latter was studied in mutants lacking either of the two enzymes using 2-oxoglutarate as the carbon substrate for glutamate biosynthesis. The results suggest that flux restriction on either reaction greatly influences the internal 2-oxoglutarate level. Additional study indicates that KgtP, a 2-oxoglutarate proton symporter, functions to recover the leakage loss of 2-oxoglutarate. This recovery mechanism benefits the measurement of cellular 2-oxoglutarate level in practice by limiting contamination from 2-oxoglutarate leakage.

Pembagian Harta Waris dalam Tradisi Masyarakat Muslim di Gorontalo

2019 ◽  
Vol 13 (2) ◽  
pp. 187-202
Author(s):  
Hamid Pongoliu
Keyword(s):  
Islamic Law ◽  
Sharia Law ◽  
The Will ◽  
The Law

Gorontalo has a customary principle derived from sharia law, and the sharia law is sourced from the Qur'an, hadith, ijmak and qiyas (adati-hula'a to syara'a, syara'a hula'a to Kitabi), which should reflect the existence of the implementation of the distribution of inheritance in Islam in the Gorontalo community. This customary principle can be a source of law if it is a rational act, not immorality, done always repeatedly, does not bring harm and does not conflict with the law of sharak. But in reality there is the implementation of inheritance that violates Islamic law, namely the distribution by way of deliberation, the determination of the amount of heirs equally, the delay in the distribution of inheritance, wills with houses given to girls, wills not to distribute inheritance, distribution of assets it depends on the will of the heir and the delay in the distribution of inheritance on the grounds that one of the parents is still alive. The distribution by deliberation and determination of the amount of the portion for each heir are equally acceptable as long as they follow the guidelines of the Compilation of Islamic Law article 183 and the concept of takharruj which was previously preceded by the Shari'a division. After the heirs know the size of the portion, then they may agree to share it in their own way or leave the inheritance according to Shari'a and agree to give to each other with other heirs.

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