Long range 13C1H coupling constants at bridgehead carbons in some naphthalene and quinoline derivatives, “cross” ring and “through” ring interactions

The ³J_CH couplings at bridgehead carbons in naphthalene and quinoline derivatives have been classified as “through” ring and “cross” ring interactions. Further divisions of the couplings have been introduced in an attempt to rationalize the interactions such that they may be used for structural assignments. The influence of central π-bond order and of the heterocyclic nitrogen atom on the couplings has been discussed. From a study of the ³J couplings at C-9 and C-10 in 45 quinoline derivatives the coupling constant ranges observed were “through” ring (via 9,10-bond): J₉₄ 4.9–6.1 Hz, J₉₅ 5.5–7.3 Hz, J_10.8 4.1–5.3 Hz; “cross” ring: J₉₂ 11.0–13.5 Hz, J₉₇ 6.7–9.8 Hz, J_10.3 4.4–7.3 Hz, J_10.6 5.2–9.1 Hz.     

Genome Mining of Pseudomonas Species: Diversity and Evolution of Metabolic and Biosynthetic Potential

Microbial genome sequencing has uncovered a myriad of natural products (NPs) that have yet to be explored. Bacteria in the genus Pseudomonas serve as pathogens, plant growth promoters, and therapeutically, industrially, and environmentally important microorganisms. Though most species of Pseudomonas have a large number of NP biosynthetic gene clusters (BGCs) in their genomes, it is difficult to link many of these BGCs with products under current laboratory conditions. In order to gain new insights into the diversity, distribution, and evolution of these BGCs in Pseudomonas for the discovery of unexplored NPs, we applied several bioinformatic programming approaches to characterize BGCs from Pseudomonas reference genome sequences available in public databases along with phylogenetic and genomic comparison. Our research revealed that most BGCs in the genomes of Pseudomonas species have a high diversity for NPs at the species and subspecies levels and built the correlation of species with BGC taxonomic ranges. These data will pave the way for the algorithmic detection of species- and subspecies-specific pathways for NP development.     

An endochronic theory accounting for deformation induced anisotropy of metals under biaxial load

Using the experimental results of yield surfaces obtained by Wu and Yeh [1991] (Int. J. Plasticity, 7, 803) for 304 stainless steel, this work provides a verification of the endochronic theory of plasticity accounting for deformation induced anisotropy. The experiments were performed under proportional loading conditions. The main difference between this paper and other papers that attempt to describe the distortion of a yield surface is that, in addition to distortion, motion of yield surface (kinematic hardening) has also been addressed by this paper. The result has shown that the theory predicts the experimental data with substantial accuracy. However, since in this theory the plastic strain increment, although normal to the initial yield surface, is in the radial direction emanating from the center of the subsequent yield surface, validity of the present model must be further studied for the case involving nonproportional loading conditions.     

Gorenstein子范畴与相对奇点范畴

令A是阿贝尔范畴, T是A的一个自正交子范畴, 且T中每个对象均有有限投射维数和内射维数. 假设左Gorenstein子范畴lG(T)等于T的右正交类,且右Gorenstein子范畴rG(T)等于T的左正交类,我们证明了Gorenstein子范畴$G(T)$等于T的左正交类与T的右正交类之交,并且证明了它们的稳定范畴三角等价于A关于T的相对奇点范畴.作为应用,令$R$是有有限左自内射维数的左诺特环, $_RC_s$是半对偶化双模,且所有内射左$R$-模的平坦维数的上确界有限, 我们证明了 若$\mbox{}_RC$有有限内射（平坦）维数且$C$的右正交类包含$R$,则存在从$C$-Gorenstein投射模与关于$C$的Bass类的交到关于$C$-投射模的相对奇点范畴间的三角等价,推广了某些经典的结果.     

An application of the method of finite Markov chain imbedding to runs tests

The method of finite Markov chain imbedding developed by Fu and Koutras (1994) has become a popular and useful tool for studying runs and patterns-related problems. In this article, their approach is used as an alternative for obtaining the exact conditional distribution of the success runs statistic given the number of successes in a sequence of n i.i.d. Bernoulli trials, which, in the past, was computed mainly from traditional combinatorics.     

Travelling solitary wave solutions to a compound KdV-Burgers equation

Explicit travelling solitary wave solutions to a compound KdV-Burgers equation are obtained by using an automated method. A two-dimensional generalization is discussed.