The Structure of Scientific Revolutions

Kuhn, Thomas S.; Hawkins, David

doi:10.1119/1.1969660

Cited by 416 publications

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“…When a solution of the crystalline ammonium salt of 3-deoxy D-mannO-OCtUlOSOniC acid in 0.1 N sulphuric acid was treated with periodate at 0" and the kinetics of periodate reduction and j3-formyl-pyruvate formation were followed (Fig.l), it was found that 3 molar equivalents of periodate were reduced within 6-7 h and that, at the same time, the amount of /$formy1 pyruvic acid liberated attained its maximum. The molar extinction coefficient reached a t this point the value of 95 x lo3 and remained virtually constant for the next 10 h. A slow, apparently linear decrease was then observed during 50 h. The molar extinction coefficient, 95-98 x lo3, was about 1501, higher than the one ( 8 1~1 0~) given [24] for the crystalline dye. (Kuhn and Lutz [24] established the extinction coefficient for an aqueous solution a t (presumably) pH 7, while in our conditions the extinction coefficient is measured in acid solution ; we found that the extinction coefficient of the dye formed from b-formyl-pyruvate and thiobarbiturate varies with the pH ; the same observation was made for the dye formed from malonaldehyde and thiobarbiturate [25].)…”

Section: Periodate Oxidation and Thiobccrbiturate Test Of 3-deoxy D-mmentioning

confidence: 73%

“…Separation of the keto-acid The most extensively used method for the estimation of 3-deoxy aldulosonic acids is based on the observation [gal that, when treated with periodate, these acids give rise to j3-formyl-pyruvic acid (VI), which, upon condensation with thiobarbituric acid, forms a red dye. The structure of the dye formed, as well as its molar extinction coefficient in aqueous and in cyclohexanone solutions, have been established by Kuhn and Lutz [24] ; it has an absorption maximum a t 549 nm. This dye can be differentiated from a similar one ( A, , , 532), which is formed from malonaldehyde and thiobarbituric acid in essentially the same conditions, by its instability towards base [3, 261 and its slightly different absorption maximum.…”

Section: Periodate Oxidation and Thiobccrbiturate Test Of 3-deoxy D-mmentioning

confidence: 98%

Section: Periodate Oxidation and Thiobccrbiturate Test Of 3-deoxy D-mmentioning

confidence: 99%

“…Consequently, they should all form, when estimated by Weissbach and Hurwitz's method [gal, the same amount of red dye and their molar extinction coefficient ought to be identical with that of the dye synthesised by Kuhn and Lutz [24]. I n fact, widely varying extinction coefficients have been [26,27], and N-acetyl neuraminic acid (65 to 68 x lo3; 70.7 x lo3; 57 x lo3) [24,26,28], most of them being considerably lower than that of the dye (81.5 x lo3 in water; 133 x lo3 in cyclohexanone) [24]. The issue is further complicated by the fact that maximal colour yields are obtained only if the heating period is about 10 min [gal and that the molar extinction coefficient increases considerably if the red dye is extracted into acid butanol [26] or cyclohexanone [24,27].…”

Section: Periodate Oxidation and Thiobccrbiturate Test Of 3-deoxy D-mmentioning

confidence: 99%

“…I n fact, widely varying extinction coefficients have been [26,27], and N-acetyl neuraminic acid (65 to 68 x lo3; 70.7 x lo3; 57 x lo3) [24,26,28], most of them being considerably lower than that of the dye (81.5 x lo3 in water; 133 x lo3 in cyclohexanone) [24]. The issue is further complicated by the fact that maximal colour yields are obtained only if the heating period is about 10 min [gal and that the molar extinction coefficient increases considerably if the red dye is extracted into acid butanol [26] or cyclohexanone [24,27]. It has been observed during this work that solutions containing the red dye, when diluted with an equal volume of ethanol, have the same absorbance as undiluted solutions.…”

Section: Periodate Oxidation and Thiobccrbiturate Test Of 3-deoxy D-mmentioning

confidence: 99%

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Chemical Synthesis and Quantitative Estimation of 3‐Deoxy d‐manno‐Octulosonic Acid

Charon¹,

Sarfati²,

Strobach

et al. 1969

European Journal of Biochemistry

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3-Deoxy D-manno-octulosonic acid has been synthesised starting from D-mannose via 2-deoxy D-manno heptose, cyanohydrine addition, and selective oxidation of the epimeric hydroxyl group of the resulting 3-deoxy octonic acids. When treated with periodate in 0.1 N sulphuric acid solution a t O", the deoxy octulosonic acid and other 3-deoxy aldulosonic acids all yield one molar equivalent of P-formyl pyruvate. Conditions are described in which /I-formyl pyruvate can be estimated by the thiobarbituric acid method ; hence, when treated successively with periodate and thiobarbiturate, all 3-deoxy aldulosonic acids have the same molar extinction coefficient and eight carbon atoms are known to be important intermediates of carbohydrate metabolism in various organisms, a general method was sought by which these compounds, as well as their phosphate esters, could be made readily accessible. In 1944 it was reported that o-gluconic acid and D-galactonic acid could be oxidised to aldulosonic acids by chlorate in the presence of a vanadium pentoxide catalyst [lo]. It was therefore expected that similar treatment of 3-deoxy aldonic acids would afford the corresponding aldulosonic acids. This was found to be the case : the present paper reports an unambiguous chemical synthesis of 3-deoxy D-manno-octulosonic acid starting from D-mannose. Conditions are described in which 3-deoxy D-manno-octulosonic acid and other 3-deoxy aldulosonic acids, when treated with periodate, yield one molar equivalent of ,9-formyl pyruvate; these acids can thus be estimated quantitatively in the thiobarbituric acid assay without standards. EXPERIMENTAL PROCEDURESXynthesis of 3-Deoxy D-manno-Octulosonic Acid ( V ) 1,2-Di-deoxy-l-nitro-3,4,5,6,7-penta-O-acetyl D-manno-heptene [ll, 121 (10 g) in 600 ml absolute ethanol was hydrogenated over 1 g palladium black, until 1.05 moles of hydrogen (570 ml a t 25" and 760 mm) had been consumed. The filtered solution was then concentrated in vacuo to a crystallising syrup, which was redissolved in 75 ml ethanol. Sodium hydroxide (100 ml, 2 N) was added in small portions to this solution kept below f5". The resulting deep red solution was then added rapidly, but dropwise, to a stirred solution of 25 ml concentrated sulphuric acid in 35 ml water maintained in an ice-bath. When the addition was complete, the reaction mixture was diluted with 1.5 1 water and neutralised with solid calcium carbonate. All solids were removed by filtration, the combined filtrate and washings passed through columns of ion exchange resins (Amberlite IR 120 H+ and I R 45 OH-, 250 ml each) and the effluent was concentrated in vacuo to a small volume.Sodium hydrogen carbonate (3.13 g) was added to the above solution of crude 2-deoxy D-mannoheptose and the volume adjusted to 186ml with water. This mixture was then added to 1.5 g sodium hydroxide and 3.0 g potassium cyanide in 186 ml water frozen to the walls of a 1 1 round bottomed flask. The flask was agitated until the mixture became homogeneous and then set aside a t room temperature overnig...

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Section: Periodate Oxidation and Thiobccrbiturate Test Of 3-deoxy D-mmentioning

confidence: 73%

Section: Periodate Oxidation and Thiobccrbiturate Test Of 3-deoxy D-mmentioning

confidence: 98%

Section: Periodate Oxidation and Thiobccrbiturate Test Of 3-deoxy D-mmentioning

confidence: 99%

Section: Periodate Oxidation and Thiobccrbiturate Test Of 3-deoxy D-mmentioning

confidence: 99%

Section: Periodate Oxidation and Thiobccrbiturate Test Of 3-deoxy D-mmentioning

confidence: 99%

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Chemical Synthesis and Quantitative Estimation of 3‐Deoxy d‐manno‐Octulosonic Acid

Charon¹,

Sarfati²,

Strobach

et al. 1969

European Journal of Biochemistry

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Needed Innovation in Digital Health and Smartphone Applications for Mental Health

2017

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The promise of smartphone applications and connected technologies for mental health to advance diagnosis, augment treatment, and expand access has received much attention. Mental health disorders represent the leading cause of the loss of years of life because of disability and premature mortality and also contribute to employee absenteeism and lost productivity in economically established countries such as the United States. The potential of smartphone applications to offer new, at-your-fingertips tools and resources for mental health care is frequently cited.But this potential is not the only reason why it is hard to ignore smartphone applications. The reality of applications for clinical care is already here. More than 10 000 mental health-related applications are available to download, and that number increases daily. As smartphones become increasingly inexpensive and available to the entire population, including those with mental illness, the accessibility, immediacy, affordability, and bold marketing claims of applications will drive more patients to use them.This new reality is worrisome: studies suggest that most mental health apps in commercial marketplaces do not conform to clinical guidelines. Some may even offer dangerous recommendations, such as one application that advises people experiencing a bipolar manic episode to drink hard alcohol before bedtime to assist with sleeping. 2 It is likely that most of these nonevidencebased applications may distract patients and potentially cause them to delay seeking care. Many applications do not respect the privacy of personal health information, and the price of a free application is often buried in a complex privacy policy requiring college reading comprehension-that price being the right to market and sell your data. 3 Certainly there are exceptions, as a handful of safe, evidence-based, and useful applications exist. Still, these helpful applications may be to difficult to find among hundreds of more problematic applications. Finding these valuable applications, furthermore, is a challenge for both patients and clinicians.Mental health technologies like smartphone applications have not been thoroughly investigated through clinical science or overseen through regulatory control. Instead, there is a void in which the potential and preshpent reality of health applications are confusing, marred

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Contemporary Sociological Theory

Ritzer

2011

The Wiley‐Blackwell Companion to Sociology

144

114

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The Structure of Scientific Revolutions

Abstract: Articles you may be interested inEinstein and Lorentz: The structure of a scientific revolution Am.

Cited by 416 publications

References 0 publications

Chemical Synthesis and Quantitative Estimation of 3‐Deoxy d‐manno‐Octulosonic Acid

Chemical Synthesis and Quantitative Estimation of 3‐Deoxy d‐manno‐Octulosonic Acid

Needed Innovation in Digital Health and Smartphone Applications for Mental Health

Contemporary Sociological Theory

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