Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1965-1969  (7)
  • 1
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract From Mössbauer effect measurements the magnetic momentμ=(+1.80±0.08) nm of the 83.4 keV rotational state of153Eu and the ratio of the changes of the mean square charge radiiΔ〈r 2〉 (153Eu, 83 keV)/Δ〈r 2〉 (153Eu, 103 keV)=+0.025±0.008 were determined. The results are interpreted on the basis of mixing of rotational bands by the Coriolis force.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 210 (1966), S. 645-645 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Young, adult New Zealand rabbits were immunized with rat serum albumin (RSA) (prepared by ammonium sulphate fractionation of whole rat serum, pure by the criterion of immunoelectrophoresis) and bovine serum albumin (BSA) (obtained from Pentex Incorporated, Kankakee, Illinois). The rabbits were ...
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die quantitative Bestimmung der beiden Stärkekomponenten beruht auf der Beobachtung, da\ die Jodsorption von Amylose schon bei einer Konzentration an freiem Jod [Jf] von etwa 5 · 10−5 n beendet ist, während das Amylopektin erst bei höheren [Jf]-Werten merkliche Mengen davon binden kann. Der genaue Endpunkt der Jodaufnahme von Amylose wird durch photometrische Titration bei 625 nm mit 0,005 n Jodlösung in An- und Abwesenheit einer bekannten Amylosemenge bestimmt. Aus dem Unterschied der Extinktionen vor Beginn der Reaktion des Amylopektins mit Jod wird die Amylosekonzentration des untersuchten Präparates berechnet. Für die Analyse werden je nach dem Amylosegehalt nicht mehr als 1–10 mg Probe/100 ml benötigt. Fehler der Extinktionsbestimmung: ±2–3%.
    Notes: Summary The quantitative determination of starch components is based on the observation that the uptake of iodine by amylose is complete at about 5 · 10−5 n free iodine concentration (under the conditions of the present investigations) while the amylopectin can bind iodine only at a higher free iodine concentration. The exact end-point of the iodine uptake by amylose has been determined by photometric titration at 625 nm with 0.005 n iodine solution before and after adding of a known amount of amylose to the investigated starch solution. The original amylose content has been calculated on the basis of the difference between the extinction values measured in absence and in presence of the extra-added amylose. The extinction values were determined before the beginning of the amylopectiniodine reaction. For such a determination a 1–10 mg sample is sufficient; the error of the extinction measurement is not higher than ±2–3%.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The equilibrium normality [If] of free iodine in amylose-iodine complex formation is a function of the length of the polyiodine chains. This length depends on the DP of helical segments of amylose (sDPn). Values of [If] and of the concentration of the bound iodine [Ib] were determined by the continuous photometric titration with automatic recording. Plots of [Ib] versus [If] give an integral distribution curve. Since the relation between [If] and sDPn is known, the graphic differentiation of the [Ib] versus [lf] curve furnishes the differential distribution curve, representing the mass distribution of the helical segments according to their DP. The peak of this curve is characteristic of the percentage and DP of those helical segments, which occur in the largest amount. On the basis of the differential distribution curve the polymolecularity of the investigated sample may be judged. The titration of amylose samples degraded by various methods gives different distribution curves. Titrating mixtures of samples with widely differing average DP values results in differential curves having more than one maximum.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The iodine which is added to an aqueous amylose solution is bound only partly by the amylose while forming the blue complex and partly remains free. The equilibrium normality of the free and the bound iodine at half-saturation of amylose by iodine is designated as [If]v and [Ib]w, respectively. The stability of the poly iodine chain formed within the axis of amylose helices depends on its length, i.e., indirectly on the DP of the amylose helices: the greater this stability, the lower the [If]v value. The amylose molecule consists of helical segments. Such a molecule may behave as a random coil. The average length of the helical segments in freshly prepared amylose-iodine complexes depends on temperature, pH, iodide concentration, the presence of other complex-forming agents, and the DP of the amylose. This latter factor is investigated in the present paper. By the aid of an automatically recording photometrictitrating device the coherent values of [Ib] and [If] were determined. Plotting these values against DPn for mechanochemically degraded as well as for periodateo-xidized amyloses resulted in curves consisting of two linear sections. The break of the curves occurred between DPn 110 and 130. It was concluded that below DPn = 100 the DP of helical segments (= sDPn) is identical to the DPn of the total molecule, i.e., the molecule consists of only a single, relatively stiff helix. Above this limit the molecule contains several helical segments. The DP of these helical segments can be calculated as follows: sDPn = 141.1 - 10.2 × 105[If]v. This equation is considered to be valid for 0.5-0.6 mg. amylose in 100 ml. 0.1N HCl at 20°C., λ = 650 mμ, euuvet diameter 3.4 cm., the feed rate of the iodate-iodide titrating solution (in acid medium resulting in a 5 × 10-3N I2 solution with a molar iodide to iodine ratio of 1.5) is 0.4ml./min. Amylose molecules of, e.g., DPn = 1380 consist of an average of 11.4 segments having a DP of about 120 and consisting of an average of 15-18 helical turns.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In aqueous solutions of the amylase-iodine complex the concentration of free iodine [If]v after reaching equilibrium (or closely approximating it) is determined by the following factors: temperature, pH, concentration of iodide ions and amylose, and DP of amylose. In the present paper the role of temperature, amylose concentration, and DP has been investigated. At half-saturation of amylose by iodine, the reciprocal value of free iodine defines the equilibrium constant: 1/[If]v = K. The relation between [If]v, in normality and temperature is the following: 5 + log [If]v = -(2.132/T) + 8.52, for DPn = 1290, 0.4 mg. amylose in 100 ml. 0.1N HCl. The value of the energy of activation Ea between 2 and 52°C. is 9.72 kcal./mole. The influence of amylose concentration [Am] on photometrically determined [If]v, at 20°C, in the range of 0.1-1.2 mg./100 ml. 0.1 N HCl for DPn = 1290 is: 5 + log [If]v = 0.209 - 0.047 log [Am]. At [Am] = 0.6 mg. amylose/ 100 ml. 0.1 N HCl and 20°C, the value of [If]v depends on DPn as follows: 5 + log [If]v = 0.085 = + 0.222 log (104/DPn). These above equations are summarized by the relation: [If]v = exp {16.865 - (Ea/RT)}[Am]0.047(104/DPn)0.222 ×10-5 Considering that the determination of [If]v by automatic photometric titration can be performed quickly and with appropriate reproducibility, this method is convenient for a rapid empirical and approximate determination of DP of amylose on a microscale. The iodine-binding capacity [IBC] as well as the value of λmax, have been also investigated as functions of DPn, by photometric and by amperometric titration.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...