CC-1065 and the duocarmycins: unraveling the keys to a new class of naturally derived DNA alkylating agents.

Key studies defining the DNA alkylation properties and selectivity of a new class of exceptionally potent, naturally occurring antitumor antibiotics including CC-1065, duocarmycin A, and duocarmycin SA are reviewed. Recent studies conducted with synthetic agents containing deep-seated structural changes and the unnatural enantiomers of the natural products and related analogs have defined the structural basis for the sequence-selective alkylation of duplex DNA and fundamental relationships between chemical structure, functional reactivity, and biological properties. The agents undergo a reversible, stereoelectronically controlled adenine-N3 addition to the least substituted carbon of the activated cyclopropane within selected AT-rich sites. The preferential AT-rich non-covalent binding selectivity of the agents within the narrower, deeper AT-rich minor groove and the steric accessibility to the alkylation site that accompanies deep AT-rich minor groove penetration control the sequence-selective DNA alkylation reaction and stabilize the resulting adduct. For the agents that possess sufficient reactivity to alkylate DNA, a direct relationship between chemical or functional stability and biological potency has been defined.

Going beyond traditional QA systems: challenges and keys in opinion question answering

The treatment of factual data has been widely studied in different areas of Natural Language Processing (NLP). However, processing subjective information still poses important challenges. This paper presents research aimed at assessing techniques that have been suggested as appropriate in the context of subjective - Opinion Question Answering (OQA). We evaluate the performance of an OQA with these new components and propose methods to optimally tackle the issues encountered. We assess the impact of including additional resources and processes with the purpose of improving the system performance on two distinct blog datasets. The improvements obtained for the different combination of tools are statistically significant. We thus conclude that the proposed approach is adequate for the OQA task, offering a good strategy to deal with opinionated questions.

Keys: Kenya youth scenarios, 2011

Kenya youth scenarios are projections of alternative pathways into the future that explore the dynamic interaction between the social, political, technological, environmental and economic forces operating within a given context (such as a nation or local communtiy). It is important to note that scenarios are not predictions of what will happen, but rather, identify what may happen.

Woody plants of the western national parks; containing keys for the identification of trees and shrubs, by Virginia Long Bailey and Harold Edwards Bailey.

no.4

Pictorial keys to arthropods, reptiles, birds and mammals of public health significance.

Mode of access: Internet.

Sanderson's duettinos, or, Select violin miscellany : comprising a series of the most esteemed songs, airs, marches, waltzes, quadrilles, &c arranged in their proper keys as duetts for two violins /

Mode of access: Internet.

Modern British permanent way. Treating of rails, chairs, fishbolts, fishplates, keys, sleepers, ballast, rail-joints, points and crossings, &c.

"Originally written as a series of articles for ʻThe Railway Newsʾ, in which they appeared at various periods between the years 1911 and 1914."--Pref.

The keys to prosperity.

Bibliographical footnotes.

Polyglot reader, and guide for translation : consisting of a series of English extracts, with their translation into French, German, Spanish, and Italian : the several parts designed to serve as mutual keys /

[v. 1] English text -- [v. 2] German translation / Reinhold Solger. 1867. -- [v. 3] Spanish translation. 1870. -- [v. 4] Italian translation / Vincenzo Botta. 1856.

Keys to spring plants,

"For the identification of the Pteridophyta, Gymnospermae and the commoner species of early-flowering Angiospermae found in the vicinity of Ithaca, New York."

Pictorial keys to anthropods, reptiles, birds and mammals of public health importance.

Bibliography: p. 187-192.