K Derivatives

Midey A J and Viggiano A A 1998 Rate constants for the reaction of Ar" with O2 and CO as a function of temperature from 300 to 1400 K derivation of rotational and vibrational energy effects J. Chem. Phys. at press... 

Figure 6.4 Schematic relationship between various experimental quantities (Rp, n j, and r) and the rate constants (k j,kp, and k ) derived therefrom.

Plots of the bursting pressures of the Ni—Cr—Mo cylinders (EN 25) vs k derived from equations 16 and 17 show that neither equation is in such good agreement with the experimental results as is the curve derived from Manning s theory. Similar conclusions have been reached for cylinders made of other materials which have been tested (16). Manning s analytical procedure may be programmed for computation and, although torsion tests are not as commonly specified as tension tests, they are not difficult or expensive to carry out (20). 

Although vitamin K is a fat soluble vitamin, only little stores are found in the body which have to be refilled permanently via dietary input. The role of vitamin K derived from bacteria in the colon is controversely discussed, as the concentration of biliary acids for the resorption the fatsoluble vitamin K is very low in the colon. In addition, only diseases of the small intestine lead to a deficit in vitamin K concentration which cannot be restored by K2 production of colonic bacteria. However, watersoluble vitamin Ks can be resorbed by the colonic mucosa. Maybe because of the little stores for vitamin K, the process of vitamin K-dependent carboxylation of proteins is part of a cycle with several steps during which vitamin K normally is regenerated (see Fig. 1) and thus can be used several times. 

Generally, in the nucleophilic addition to carbonyl groups, either magnesium compounds or alkali metal compounds (such as the Li, Na and K derivatives) are used. In some cases even potassium carbonate or piperidine were used as the base for condensation with sulfones. Good results were obtained when concentrated aqueous NaOH was used under phase-transfer conditions288,297,333. 

P Li]iiniil/M k pp fxP in min 1 k derived app from Smets mechanism kapp derived from the linear relation... 

Kaltseis et al. [234] have investigated the recoil-free fraction of the 46.5 keV transition of W in anhydrous lithium tungstate. Their results can be expressed by an effective Debye temperature of 172 9 K which is in good agreement with a value of 205 40 K derived from X-ray diffraction measurements of Li2W04 powder. 

Another cyclic boron catalyst K, derived from ra x-2-aminocyclohexanc-methanol, can be prepared with a quaternary nitrogen that enhances activity.101 This particular catalyst is not very stable, but it is highly active. 

Mean square displacements of C100 at 509°K derived from Nose-Hoover-MD... 

Figure 3. Variation of calibration coefficients, Kc and K, derived from the calculation.

Bottom panel Observed and synthetic Ha profiles for HD 140283 (black 5760K, grey 5560 K). The data was retrieved from the VLT archive (observing date 2000-06-15), reduced using REDUCE and rectified using parabolic fits to the continua in adjacent orders. Notice the variable telluric features which somewhat suppress the blue wing. An effective temperature of 5560 K (best estimate of [3]) is clearly too low, 5760 K (derived from the UVES POP spectrum) too high. At a S/N of 150, observational systematic errors are thus of the order of at least 100 K. 

Fig. 7 b. Oxygen atom pair correlation functions for polycrystalline ice Ih (top) and for H20(as) (bottom), both prepared and studied at 77 K, derived from X-ray diffraction (from Ref. 27>)... 

Using a value of K (derived from Eq. 5.5) suggested that in the presence of ultrasound, and the absence of initiator, ultrasound was able to provide an equivalent initiator concentration of 6 x 10 mol dm. In general the work was important in that it showed a reciprocal volume dependence rather than a (l/Vh j dependence as shown by Kruus. It also showed that in the absence of initiator, it was possible to... 

Potassium - the atomic number is 19 and the chemical symbol is K. The name derives from the English potash or pot ashes since it is found in caustic potash (KOH). The chemical symbol K derives from the Latin kalium via the Arabic qali for alkali. It was first isolated by Humphry Davy in 1807 from electrolyosis of potash (KOH). 

Binding of heme by isolated N-domain causes a change in sedimentation coefficient consistent with a more compact conformation and leads to the more avid association with the C-domain (125). Sedimentation equilibrium analysis showed that the Kd decreases from 55 pM to 0.8 pM (Fig. 5) (106). In addition, the calorimetric AH (-1-11 kcal/mol) and AS (-1-65 kcal/mol K) for the heme-N-domain-C-domain interaction and the AH (-3.6 kcal/mol) and AS (-1-8.1 kcal/mol K) derived from van t Hoff analysis of ultracentrifuge data for the interaction in the absence of heme indicate that hydrophobic interactions predominate in the presence of heme and a mix (e.g., hydrophobic and van der Waals forces) drives the interaction in the absence of heme. However, FTIR spectra (Fig. 6) indicate that little change in the secondary structure of domains or intact hemopexin occurs upon heme binding (104). 

Vitamin K promotes the hepatic y-car-boxylation of glutamate residues on the precursors of factors II, VII, IX, and X, as well as that of other proteins, e.g., protein C, protein S, or osteocalcin. Carboxyl groups are required for Ca +-mediat-ed binding to phospholipid surfaces (p, 142). There are several vitamin K derivatives of different origins Ichlorophyllous plants I<2 from gut bacteria and I<3 (menadione) synthesized chemically. All are hydrophobic and require bile acids for absorption. 

The yellow color of the AM 13,1 colonies is due to their content of compound 26. In most other cases, yellow cultures owe their color to the carotenoid zea-xanthin (Hel21) or one of the many vitamin K derivatives (e.g., menaquinone MK6 in Hel21). 

Tab. 16 Standard potential forthe first redox system of each POM and second-order rate constant k derived from DPSC experiments on HPB/NADH systems at pH = 7. Each value of k is the average of at least five experiments. The values of y are not necessary, but have been added to give a better idea of the experimental conditions (taken from Ref. 174)...

Equation (3), however, was developed for a gas chromatographic column and in the case of a liquid chromatographic column, the resistance to mass transfer in the mobile phase should be taken into account. Van Deemter et al did not derive an expression for fi(k ) for the mobile phase and it was left to Purnell (3) to suggest that the function of (k ), employed by Golay (4) for the resistance to mass transfer in the mobile phase in his rate equation for capillary columns, would also be appropriate for a packed column in LC. The form of f (k ) derived by Golay was as follows,... 

TABLE 13.4. Relative Selectivities (S = logkaz/k ) Derived from Azide Trapping of... 

To prove the exactness at Derk(5,l) note that r(d) = 0 iff p R[IJ— R has a section as a morphism of S-algebras, iff there exists a k-derivation R — 1 whose restriction to 5 is d, this proves the assertion. 

This last circumstance can be seen directly observing that if F = h for some R in CL then two homomorphisms f,g. R — A have the same image in F(A) Homa.(R,A) iff there exists a k-derivation d R — k (which is uniquely determined) such that... 

The last row entry in Table 23.6 is also problematic, since the value of irev/ifwd (0.33) is too low to be reliably measured by the Nicholson method the values of kobsx and k,. derived from the last row should therefore be viewed as lower limits. It is the data at the three CH3CN concentrations of 8.3, 12.8, and 32.2 mAf that are most appropriate for evaluation of the rate constant, and the resultant values in Table 23.6 are consistent with rate = 45[CH3CN] s 1. 

The vibrational frequencies of the gas phase spectra of C60 taken in the range of temperature comprised between 879 and 1,212 K were extrapolated to 0 K to give the theoretical position of these bands an approach of astrochemical interest (Nemes et al. 1994). The results of that extrapolation are reported in Table 10.1. It can be observed that the vibrational frequencies at 0 K derived from the gas phase data are shifted toward higher wavenumbers in comparison to the data derived from C60 in KBr matrix (and extrapolated to 0 K) by 6.2 cm-1 for the Flu(l) mode, by 7.7 cm-1 for the Flu(3) and by 4.6 cm-1 for the Flu(4) mode. Instead only for the Flu(2) mode the band extrapolated to 0 K is shifted to shorter wavenumbers by 2.4 cm-1 in comparison to the data in KBr matrix extrapolated at 0 K. 

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