Undetermined

We define the field intensity tensor Fi,c as a function of a so far undetermined vector operator X = Xj, and of the partial derivatives dt... 

Henee, for this non-degenerate root, one is able to solve for all of the vj elements in terms of one element that is yet undetermined. 

All of these points are entirely reasonable. What is confusing about Eq. (9.83) is the step length and the undetermined constant K. Fortunately, they can both be eliminated in a single step. If Eq. (9.83) is a solution to Eq. (9.74), then both sides of the latter must be equal when the indicated operations are performed on Eq. (9.83). Carrying out these operations yields the following ... 

Light and photosynthetic electron transport convert DPEs into free radicals of undetermined stmcture. The radicals produced in the presence of the bipyridinium and DPE herbicides decrease leaf chlorophyll and carotenoid content and initiate general destmction of chloroplasts with concomitant formation of short-chain hydrocarbons from polyunsaturated fatty acids (37,97). 

The pathways for thiamine biosynthesis have been elucidated only partiy. Thiamine pyrophosphate is made universally from the precursors 4-amino-5-hydroxymethyl-2-methylpytimidinepyrophosphate [841-01-0] (47) and 4-methyl-5-(2-hydroxyethyl)thiazolephosphate [3269-79-2] (48), but there appear to be different pathways ia the eadier steps. In bacteria, the early steps of the pyrimidine biosynthesis are same as those of purine nucleotide biosynthesis, 5-Aminoimidazole ribotide [41535-66-4] (AIR) (49) appears to be the sole and last common iatermediate ultimately the elements are suppHed by glycine, formate, and ribose. AIR is rearranged in a complex manner to the pyrimidine by an as-yet undetermined mechanism. In yeasts, the pathway to the pyrimidine is less well understood and maybe different (74—83) (Fig. 9). 

Nitration of 3-phenyl-1,2-benzisoxazole with fuming nitric acid has been shown to give dinitro products of undetermined substitution pattern (67AHC(8)277, p. 290>. However, more satisfactory studies have now been described, especially on the kinetics and mechanism of nitration of 3-methyl-l,2-benzisoxazole (77JCS(P2)47). Nitration in cold, concentrated mixed acids yields the 5-nitro derivative exclusively, nitration in 80-90% sulfuric acid occurring on the free base whereas at higher acidities the conjugate acid is the species involved in the nitration. 

Method of Undetermined Coejftcients If Q x) is a product or linear combination of products of the functions a, x p a positive... 

The synthetic procedure described is based on that reported earlier for the synthesis on a smaller scale of anthracene, benz[a]anthracene, chrysene, dibenz[a,c]anthracene, and phenanthrene in excellent yields from the corresponding quinones. Although reduction of quinones with HI and phosphorus was described in the older literature, relatively drastic conditions were employed and mixtures of polyhydrogenated derivatives were the principal products. The relatively milder experimental procedure employed herein appears generally applicable to the reduction of both ortho- and para-quinones directly to the fully aromatic polycyclic arenes. The method is apparently inapplicable to quinones having an olefinic bond, such as o-naphthoquinone, since an analogous reaction of the latter provides a product of undetermined structure (unpublished result). As shown previously, phenols and hydro-quinones, implicated as intermediates in the reduction of quinones by HI, can also be smoothly deoxygenated to fully aromatic polycyclic arenes under conditions similar to those described herein. 

Optimization of external parameters tends to be more difficult as the quantity of the target data is decreased relative to the number of parameters to be optimized compared to the internal parameters, leaving the solution more undetermined. This increases the... 

Long loop regions are often flexible and can frequently adopt several different conformations, making them "invisible" in x-ray structure determinations and undetermined in NMR studies. Such loops are frequently involved in the function of the protein and can switch from an "open" conformation, which allows access to the active site, to a "closed" conformation, which shields reactive groups in the active site from water. 

Lipoxygenation is the major pathway of dioxygenation of arachidonic acid in blood platelets and leads to the 12-5-hydroperoxy acid 12-HPETE and the corresponding 12-hydroxy acid 12-HETE. Several pathways for the synthesis of 12-HETE have been developed. However, despite the availability of this substance, its biological role remains undetermined. 

Mahonia aquifolium Nutt. Berberis aquifolium Pursh.) Berberine, berbamine, oxyacanthine, a phenolic base, m.p. 190-3°, and undetermined alkaloids. 

When the methine base derived from trilobamine diethyl ether ethiodide is oxidised by permanganate it furnishes 2-ethoxydiphenyl ether 5 4 -dicarboxylie acid, identical with that (XXXIV p. 348, R = Et) similarly formed from oxyacanthine (p. 347) or dauricine (p. 353) and in the present case derived from the diphenyl ether residue represented by rings (1) and (2) in formula (A) or (B). This fixes the position of one hydroxyl group at OR in (A) or (B) the position of the second is still undetermined but it may well be OR in ring (3) of (A) or ring (4) of (B). ... 

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