bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemistry for the synthesis of nucleobase-modified peptide nucleic acid
Authors: Hudson R. H. E. , Viirre R. D. , Liu Y. H. , Wojciechowski F. , Dambenieks A. K. 
Published: October 2007

Abstract
Peptide nucleic acid (PNA) presents a versatile scaffold for chemical modifications that may benefit its solubility and hybridization properties, conjugation chemistry, cell membrane permeability, and so forth. We have employed straightforward chemical methods for the synthesis of PNA monomers containing C5-or C6-modified pyrimidines.The C5-modified pyrimidines are based on 5-hydroxymethyl-uracil or cytosine, or are achieved by cross-coupling from the 5-iodonucleobase derivatives, while C6 modifications are accessed from 6-carboxyuracil (orotic acid). We have also developed an on-resin activation/conversion of uracil-containing PNA oligomers to N
4-cytosine-containing derivatives.
Conformationally restricted cationic polyamide analogs of nucleic acids: Design, synthesis, and DNA/RNA binding studies
Authors: Kumar V. A. , D'Costa Moneesha , Lonkar P. S. , Meena  , Pallan P. S. , Ganesh K. N. 
Published: October 2007

Abstract
The remarkable medicinal importance of the achiral, acyclic, and uncharged aminoethylglycyl peptide nucleic acids (aegPNAs) as DNA/RNA mimics has challenged chemists to circumvent the limitations of their in vivo efficacy. In this context, we have designed conformationally restricted five- and six-membered cyclic PNA analogs by introduction of chemical bridges in aegPNAs leading to a large variety of structures with defined configurations and conformational preferences, effecting concomitant installation of a positive charge in the backbone. The synthesis and biophysical properties of these cationic aminoethylprolyl PNAs, pyrrolidine PNAs, and piperidine PNAs endowed with increased water solubility and affinity toward target nucleic acids is presented. These nucleic acid analogs as lead structures are a part of a chemical evolution process that might give rise to a synthetic nucleic acid analog having optimum properties for medicinal applications.
Properties and units in the clinical laboratory sciences. Part XVIII. Properties and units in clinical molecular biology (IUPAC Technical Report)
Authors: de Araujo P. Soares , Zingales Bianca , Alía-Ramos Pedro , Blanco-Font Aurora , Fuentes-Arderiu X. , Mannhalter Christine , Varming K. , Bojesen Stig , Bruunshuus Ivan , Olesen H. 
Published: October 2007

This document describes the introduction of the concept of property in the field of molecular biology for the presentation of results of clinical laboratory investigations of genes and mutations. It follows the IUPAC–IFCC systematic rules and attempts to create a common base for communication between the clinical laboratory sciences, the medical practitioner, and the molecular biology areas of knowledge.Because of the plethora of possible structural variations in the outcome of analysis, the designation of components is restricted to the symbols of genes as identified by the Human Genome Nomenclature Database (HUGO). The listing of properties having DNA as system comprises all symbols in the HUGO database except for symbols related to mitochondrial genes, while properties having RNA as system are included only when known to be in actual use. The detailed and accurate presentation of results is made by the laboratory performing the study, and it is recommended that the explicit guidelines given by Antonarakis and den Dunnen be adhered to.For electronic communication, a code (NPU) is allocated to each property identified. The complete list of properties, which is an integral part of this report, can be accessed at <www.iupac.org/publications/pac/2004/7609/7609x1799.html>.
Building a molecular-level picture of the ultrafast dynamics of the charge-transfer-to-solvent (CTTS) reaction of sodide (Na¯)
Authors: Martini I. B. , Barthel E. R. , Schwartz B. J. 
Published: October 2007

Abstract
Charge-transfer-to-solvent (CTTS) reactions represent the simplest possible electron-transfer reaction. One of the reasons that such reactions have become the subject of recent interest is that transfer of a CTTS electron from an atomic anion to the solvent involves only electronic degrees of freedom, so that all the dynamics involved in the reaction are those of the solvent. Thus, CTTS reactions provide an outstanding spectroscopic window on the dynamics of the solvent during electron transfer. In this paper, we will review our recent work studying the CTTS reaction of the sodium anion, (Na− or sodide) in a series of ether solvents. By comparing the results of ultrafast spectroscopic pump/probe experiments and mixed quantum/classical molecular dynamics simulations, we work to build a molecular-level picture of how solvent motions control the dynamics of CTTS, including the distance to which the electron is ejected and the rates of both the forward and back electron-transfer reactions.
Past, present and futute of cyclodextrin research
Authors: Szejtli J. 
Published: October 2007

Abstract
The macrocyclic cyclodextrins (enzymic conversion products of starch) were discovered in 1891, and the structures were elucidated in the mid-1930s. Their industrial significance become obvious in the 1970s, and by now thousand of tons of the three cyclodextrins (alpha-, beta-, and gamma-CD) and of their chemical derivatives and inclusion complexes are produced industrially. The outer surface of these doughnut-shaped molecules is hydrophilic, but they possess an axial open cavity, which is of hydrophobic character and capable of including other apolar molecules (or their moiety) in case of geometric compatibility. This is the essence of molecular encapsulation by inclusion complex formation.
From molecular modules to modular materials
Authors: Kurth D. G. , Liu Shaoqin , Volkmer D. 
Published: October 2007

Abstract
The combination of metallosupramolecular modules (MEMOs) as functional and amphiphiles as structural components is presented in detail to illustrate our current understanding of encapsulation using surfactants, lipids, and dendrimers. The simplicity of fabrication and the availability of the starting components allow this technique as an attractive tool to create new nanoscale molecular materials. The interaction of amphiphiles and MEMOs occurs spontaneously and is driven by the release of counterions as well as electrostatic and hydrophobic interactions.
Acid-base properties of purine residues and the effect of metal ions: Quantification of rare nucleobase tautomers
Authors: Sigel H. 
Published: October 2007

Abstract
The macro acidity constants valid for aqueous solutions of several adenine, guanine,and hypoxanthine derivatives are summarized. It is shown how the application of the corresponding constants, e.g., for 7,9-dimethyladenine, allows a quantification of the intrinsic acidic properties of the (N1)H0/+ and (N7)H+ sites via micro acidity constants, and how to use this information for the calculation of the tautomeric ratios regarding the monoprotonated species, that is, N7-N1*H versus H*N7-N1, meaning that in one isomer H+ is at the N1 site and in the other at N7. It is further shown that different metal ions coordinated to a given site, e.g., N7, lead to a different extent of acidification, e.g., at (N1)H; the effect decreases in the series Cu2+>Ni2+>Pt2+ ~Pd2+. Moreover, the application of micro acidity constants proves that the acidifications are reciprocal and identical. This means, Pt2+ coordinated to (N1)–/0 sites in guanine, hypoxanthine, or adenine residues acidifies the (N7)H+ unit to the same extent as (N7)-coordinated Pt 2+ acidifies the (N1)H0/+ site. In other words, an apparently increased basicity of N7 upon Pt2+ coordination at (N1)–/0 sites disappears if the micro acidity constants of the appropriate isocharged tautomers of the ligand are properly taken into account. There is also evidence that proton–proton interactions are more pronounced than divalent metal ion–proton interactions, and that these in turn are possibly larger than divalent metal ion–metal ion interactions. The indicated quantifications of the acid-base properties are meaningful for nucleic acids including the formation of certain nucleobase tautomers in low concentrations, which could give rise to mutations.
Molecular devices
Authors: Balzani Vincenzo , Ceroni Paola , Ferrer Belén 
Published: October 2007

Abstract
The concept of a macroscopic device can be extended to the molecular level by designing and synthesizing (supra)molecular species capable of performing specific functions. Molecular devices need energy to operate and signals to communicate with the operator. The energy needed to make a device work can be supplied as chemical energy, electrical energy, or light. Luminescence is one of the most useful techniques to monitor the operation of molecular-level devices. The extension of the concept of a device to the molecular level is of interest, not only for basic research, but also for the growth of nanoscience and the development of nanotechnology. In this article, some of the most recent experiments performed in our laboratory will be reviewed.
Pyridinium N-phenolate betaine dyes as empirical indicators of solvent polarity: Some new findings
Authors: Reichardt C. 
Published: October 2007

Abstract
Solutions of the zwitterionic betaine dye 4-(2,4,6-triphenylpyridinium-1-yl)-2,6-di- phenylphenolate are solvatochromic, thermochromic, piezochromic, and halochromic. That means the position of its longest-wavelength intramolecular charge-transfer absorption band depends on solvent polarity, solution temperature, external pressure, and the nature and concentration of added salts. The extraordinarily large negative solvatochromism of this standard betaine dye has been used to establish UV/vis spectroscopically an empirical scale of solvent polarity, called ET(30), respectively ET
N scale, meanwhile known for many organic solvents and solvent mixtures. In this review, the solvatochromic properties of some new hydrophilic and lipophilic betaine dyes with better solubility in water (respectively, nonpolar solvents), as well as some recent applications of these betaine dyes in various fields of interest [e.g., microheterogeneous (micellar) and polymer solutions, chemical sensors, as well as surface polarity of silicas, aluminas, and cellulose derivatives] are described.
Compilation of k0 and related data for NAA in the form of electronic database (IUPAC Technical Report)
Authors: Kolotov V. P. , De Corte F. 
Published: October 2007

Abstract
This report describes the principles underlying a comprehensive electronic database that contains data essential for calculation of analytical results from neutron-activation analysis (NAA) and that is available through IUPAC. The method used is a comparator method called the k
0 method, where k
0 is a dimensionless factor which is experimentally measured with high accuracy for more than 130 isotopes and which makes use of the gamma spectroscopic line for an analyte isotope relative to a gold comparator. The database contains recommended values for k
0 and other relevant nuclear data.
Workshop 1.6 QSAR and related procedures for prescreening and predicting potential endocrine-active compounds
Authors: Fujita T. 
Published: October 2007

Abstract
This workshop has been organized to cover various quantitative structure-activity relationship (QSAR) and computer aided procedures currently carried out for the prediction of the endocrine activity of unknown compounds. Each of the procedures has own scope as well as limitations. It seems inappropriate to consider that a single quantitative prediction model derived from each of these procedures could solve the entire issue. Because the model building is highly dependent on the data/knowledge about endocrine activity of a large number of existing compounds accumulated to date and the data/knowledge are growing constantly, the model has a destiny to be amended “forever ”as the structure-activity data of newly synthesized compounds are accumulated. The skepticism about in silico and QSAR procedures put forward in the past is likely to be cleared at least to some extent if not entirely by participating in this workshop.
Tandem methodology for heterocyclic synthesis
Authors: Padwa A. 
Published: October 2007

AbstractTandem methodology for heterocyclic synthesis represents a powerful approach for the rapid buildup of molecular complexity from potentially simple starting materials. Work from our laboratory has shown that the rhodium(II)-catalyzed cyclization cascade of alpha-diazo imides represents an effective method for the synthesis of a variety of heterocyclic systems. As an extension of these studies, we became interested in using a linked Pummerer/N-acyliminium ion cyclization sequence since we felt that this combination offers unique opportunities for the assemblage of complex target molecules. A synthetic method that combines transformations of different reaction types significantly broadens the scope of such procedures in synthetic chemistry. Alpha-thiocarbocations generated from the Pummerer reaction of beta-phenylsulfinylmethyl-alpha, beta-unsaturated amides can be intercepted by the adjacent amido group to produce transient amino-substituted furans which undergo subsequent Diels–Alder cycloadditions. Using this domino amido Pummerer/Diels–Alder cascade, we were able to assemble novel polycyclic systems in a single operation. The key step in the process involves the generation of a reactiveN-acyliminium ion by fragmentation of an amino-substituted [4+2]-cycloadduct. The successful synthesis of a number of alkaloids by this sequence of reactions reveals the usefulness and importance of this unique domino cascade. Application of the process for the preparation of the stenoma alkaloid stenine was recently carried out in our laboratory.
Pyridylketenes. Structure reactivity effects in nucleophilic and radical addition
Authors: Allen A. D. , Fedorov A. V. , Najafian K. , Tidwell T. T. , Vukovic S. 
Published: October 2007

Abstract
2-, 3-, and 4-Pyridylketenes have been generated in CH3CN by photochemical Wolff rearrangements and identified by their ketenyl absorption in the infrared at 2127, 2125, and 2128 cm–1, respectively. Reaction of these pyridylketenes with n-BuNH2 results in the formation of intermediate amide enols from the 3- and 4-pyridylketenes, which are then converted to the corresponding pyridylacetamides. However , 2-pyridylketene forms a long-lived 1,2-dihydropyridine intermediate stabilized by an intramolecular hydrogen bond, and this is converted to the 2-pyridylacetamide with a rate constant 107 less than those for the conversion of the amide enols from the 3- and 4-pyridylketenes to amides. Hydration of the pyridylketenes results in the formation of an acid enol intermediate in the case of the 3-isomer, while the 2- and 4-isomers form longer-lived dihydropyridines. The pyridylketenes react with the stable free radical tetramethylpiperidinyloxyl (TEMPO,TO) forming 1,2-diaddition products ArCH(OT)CO2T.
Domino reactions in the synthesis of heterocyclic natural products and analogs
Authors: Tietze L. F. , Rackelmann N. 
Published: October 2007

Abstract
Domino reactions are defined as processes of two or more bond-forming reactions under identical conditions, in which the subsequent transformation takes place at the functionalities obtained in the former transformation. They allow the efficient synthesis of complex molecules from simple substrates in an ecologically and economically favorable way. A very powerful domino process is the domino Knoevenagel–hetero-Diels–Alder reaction, in which an aldehyde or an beta-ketoester is condensed with a 1,3-dicarbonyl compound or a heteroanalog to give a 1-oxa-1,3-butadiene, which can undergo an inter- or intramolecular hetero-Diels–Alder reaction with dienophiles such as enol ethers or alkenes. The products are dihydropyrans, which can be transformed in a variety of ways. Thus, an extension of the process is the synthesis of highly substituted pyrrolidines, piperidines, and azepanes using aminoaldehydes. The process has also been employed for the enantioselective total synthesis of a variety of alkaloids, such as indol- and ipecacuanha alkaloids. In another domino process, erythrina and homoerythrina alkaloids have been prepared from simple phenylethylamines and ketoesters.
Definition of terms related to polymer blends, composites, and multiphase polymeric materials (IUPAC Recommendations 2004)
Authors: Work W. J. , Horie K. , Hess M. , Stepto R. F. T. 
Published: October 2007

Abstract
The document defines the terms most commonly encountered in the field of polymer blends and composites. The scope has been limited to mixtures in which the components differ in chemical composition or molar mass and in which the continuous phase is polymeric. Incidental thermodynamic descriptions are mainly limited to binary mixtures although, in principle, they could be generalized to multicomponent mixtures.
The document is organized into three sections. The first defines terms basic to the description of polymer mixtures. The second defines terms commonly encountered in descriptions of phase domain behavior of polymer mixtures. The third defines terms commonly encountered in the descriptions of the morphologies of phase-separated polymer mixtures.
Characterization of polyamides 6, 11, and 12. Determination of molecular weight by size exclusion chromatography (IUPAC Technical Report)
Authors: Robert E. C. , Bruessau Rudolf , Dubois J.-E. , Jacques Bernard , Meijerink Nico , Nguyen T. Q. , Niehaus D. E. , Tobisch W. A. 
Published: October 2007

Abstract
This report presents the results from IUPAC Working Party IV.2.2 of the global trial within the framework of IUPAC Commission IV.2, “Characterization of Commercial Polymers”. The results were compared on the basis of molecular weight obtained by size exclusion chromatography (SEC)using different techniques practiced in participating laboratories, the majority of which were materials suppliers. The practical methodologies used different solvents for the polymers, in particular, benzyl alcohol, 1,1,1,3,3,3 hexafluoropropan-2-ol and tetrahydrofuran; the latter solvent was used after chemical modification of the polyamides, in general with trifluoroacetic anhydride. Eight laboratories participated in the trial. The repeatability for molecular weight in each laboratory was good, whatever technique was used, the relative standard deviation averaged over all laboratories being around 3%. The deviations in distribution of molecular weights with different experimental methodologies were broader, but were reasonably good despite the diversity of methods. The differences in the distribution correspond to a confidence interval of about 30% in molecular weight.
Rheological properties and associated structural characteristics of some aromatic polycondensates including liquid-crystalline polyesters and cellulose derivatives (IUPAC Technical Report)
Authors: White J. L. , Dong L. , Han P. , Laun H. M. 
Published: October 2007

Abstract
A comparative experimental study of shear-flow rheological properties of thermotropic polymer liquid crystals by eight different laboratories is described. The materials involved four different liquid-crystalline polyesters (LCPs), a glass- fiber-filled liquid-crystalline polyester,hydroxypropyl cellulose (HPC), and two non-liquid-crystalline high-temperature polymers, a poly(etheretherketone) (PEEK), and a polyarylate (PAR). Studies were made in both steady shear-flow and dynamic oscillatory experiments. The data from the various laboratories involved were compared. The level of agreement in the data was much less for most liquid-crystalline polymers than for similar isotropic melts. The Cox –Merz rule is valid for PEEK and PAR, but not for the LCPs and HPC. The occurrence of low levels of extrudate swell and high levels of uniaxial orientation in extrudates of the LCPs and HPC is described.
Sex-Specific Association of the Glucocorticoid Receptor Gene With Extreme BMD
Authors: Peng Yu-Mei , Lei Shu-Feng , Guo Yan , Xiong Dong-Hai , Yan Han , Wang Liang , Guo Yan-Fang , Deng Hong-Wen 
Published: October 2007

Abstract
To study the role of the GR gene on BMD regulation in the Chinese, a sex-specific association study was performed. The results indicated that GR variation contributed to the extreme BMD variation in the Chinese.
Introduction: The glucocorticoid (GC) receptor (GR) gene is an important candidate gene for BMD regulation in GC-induced osteoporosis (GIO). However, no study has explored the genetic effects of the GR gene on BMD variation in the Chinese population.
Materials and Methods: Our sample consisted of 800 unrelated subjects (400 women and 400 men) with extreme age-adjusted hip BMD Z-scores selected from a population composed of 1988 normal adult Chinese Han. Four single nucleotide polymorphisms (SNPs) in the GR gene were genotyped. Both single SNP and haplotype association analyses were conducted.
Results: SNP rs1866388 (pc = 0.028) was found to be significantly associated with extreme BMD only in men. In both sexes, haplotypes involving rs1866388 and rs2918419 were found to have different frequency distributions in extremely low and high BMD groups (pp = 0.024, 0.001, and 0.002 in women and 0.002, 0.003, and 0.003 in men for window sizes of two, three, and four SNPs, respectively). Most shared haplotypes showed opposite effects between women and men.
Conclusions: For the first time, our study suggested the possible role of the GR gene on BMD regulation and sex specificity in the association of GR with extreme BMD in the Chinese.