bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syntheses with stable isotopes: Sodium cyanide‐13C
Authors: Whaley Thomas W. , Ott Donald G. 
Published: October 2006

AbstractSodium cyanide‐ 13C has been prepared in 65–70% overall yield from carbon‐13C monoxide in a three‐step synthesis proceeding through isopropyl formate‐ 13C and formamide‐ 13C as intermediates. Several. methods for the dehydration of formamide have been investigated.
Preparation of 3H‐ and 14C‐labelled contraceptive steroids
Authors: Shibata Kenyu , Osawa Yoshio , Sandberg Avery A. 
Published: October 2006

Abstract3H‐ and 14C‐Labelled ethynodiol diacetate, chlormadinone acetate, and medroxyprogesterone acetate with one label at the steroid nucleus and the other at the acetoxy group were prepared for use in studies of regio‐ and stereospecificity of metabolic hydrolysis of the steroid contraceptives. Steroidal secondary, tertiary, equatorial, and axial acetates were labelled under selective conditions using acetic anhydride.
Synthesis of 2,3‐bis(p‐methoxyphenyl) indole‐2‐14C
Authors: Thomas Richard C. 
Published: October 2006

Abstract2,3‐Bis(p‐methoxyphenyl)indole‐2‐14C was prepared at a specific activity of 1.71 mCi/mM from Ba14CO3 by a 4‐step synthetic sequence in 23% overall radiochemical yield.
Synthesis of 1,2‐3H‐oeoxycorticosterone azidoformate
Authors: Burrows Elizabeth P. , Nsergaard Jon R. , Smith Howard E. 
Published: October 2006

AbstractAn efficient synthesis of 1,2‐3H‐deoxycorticosterone azido‐formate from 1,2‐3H‐deoxyaorticorterone via the chloroformate, adaptable to microgram quantities, is described.
Synthesis of a tumor‐growth inhibitor‐dihydrochloride of 1‐nitro‐9‐/dimethylamino‐propylamino/‐acridine/C‐283/tritium labelled in the acridine ring and 14C‐labelled in the side chain
Authors: Kołodziejczyk A. , Arendt A. 
Published: October 2006

Abstract1‐Nitro‐9/dimethylaminopropylamino/‐acridine dihydro‐chloride /C‐283, ‘Ledaarin’/ is used as an anti‐twnor drug, In view of the studies on its mechanism of action. the syntheses of two specimens of this compound labelled with radioisotopes have been carried out. One of them contained C14 in the side chain and the other tritiwn in the acridine ring. 3‐Dimethylaminopropylamine /1‐C14/ prepared on the basis of K14 was used as the initial substrate for the synthesis of C‐283 labelled with 14C. It was condensed with pyridinium salt of 1‐nitro‐9‐chloroacridine.In order to introduce tritium to the acridine ring, m‐nitro‐aniline was tritiated in the aaidia solution of tritiated water.Thus obtained tritiated m‐nitroaniline was condensed by Ullman's method with o‐ahlorobenzoia acid.The N‐/3′‐nitrophenyl/anthranilia acid was then converted to the derivative of 1‐nitro‐9‐chloroacridine /2,3,4‐T3/. The specific activity of C‐283 14C labelled was 5.5 mCi/mmole and that of C‐283 tritium labelled 103 mCi/mmole.
Synthesis of 3H‐etomidate ano resolution into its enantiomers
Authors: Heykants J. J. P. , Knaeps A. G. , Janssen M. A. C. 
Published: October 2006

AbstractEtomidate, (R)‐(+)‐ethyl 1‐(1‐phenylethyl)‐1H‐inidazole‐5‐carboxylate, is a short‐acting hypnotic. Tritium was introduced in the ortho‐position of the phenyl‐group by catalytic dehalogenation of the 2‐chloro‐analogue. The homologous tritiated methyester, (+)‐methyl 1‐(1‐phenylethyl)‐1H‐imidazole‐5‐carboxylate, was hydrolyzed to the corresponding carboxylic acid. The resolution into both enantiomers was carried out by successive salt formation with (R)‐(+)‐ and (S)‐(‐)‐α‐methylbenzenemethanamine. After isolation of the diastereoisomeric salts, both enantiomers were obtained by esterification of the salts in ethanol, saturated with HCl‐gas.
Synthese von 15N‐Markierten 2‐Substituierten 2‐Thiazolinen und Analogen Thiazinen
Authors: Volford J. , Bànfi D. 
Published: October 2006

AbstractZur Untersuahung der Tautomerie des 2‐Phenylamino‐2‐thiaaolins und des analogen 1.3‐Thiaains wurde die selektive 15N‐Markierung des exo‐ bzw. endo‐Stiakstoffatomes dieser Verbindungen durahgeführt. Der Isotopeneffekt der markierten Verbindungen konnte IR‐spektroskopisah registriert werden.
Synthesis of a new adrenal cortex imaging agent 6β‐131 I‐iodomethyl‐19‐nor cholest ‐5(10)‐en‐3β‐ol (NP‐59)
Authors: Basmadjian Garabed P. , Hetzel Kenneth R. , Ice Rodney D. , Beierwaltes William H. 
Published: October 2006

AbstractA new adrenal cortex imaging agent. 6β‐131 I‐iodomethyl‐19‐norcholest‐5(10)‐en‐3β‐ol (NP‐59)[I] was synthesized by the homallylic rearrangement of 19‐iodocholesterol or directly from cholest‐5‐ene‐3β, 19‐diol‐19‐toluene‐p‐sulfonate via homoallylic rearrangement with the iodide ion as a nucleophile and subsequent exchange with Na131I. NP‐59 appears to concentrate 5 times better than 19‐iodocholesterol in the rat adrenal and is currently being evaluated as a possible diagnostic agent in man.
General methods for the preparation of deuterium and tritium‐labelled phenethylamines and phenethanollamines: Synthesis of radioactive 6‐hydroxydopamine
Authors: Rotman A. , Daly J. W. , Creveling C. R. 
Published: October 2006

AbstractA convenient synthetic method for preparation of phenethylamines and phenethanolamines labeled with deuterium or tritium has been developed. A substituted benzaldedyde is condensed with nitromethane or nitroethane and the resultant nitrostyrene is reduced with sodium borotritide or borodeuteride. Subsequent reduction of the nitro‐group and removal of blocking groups yields a phenethylamine or an a‐methylphenethylamine containing a tritium or deuterium in the benzylic position. Condensation of the substituted benzaldehyde with nitromethane or nitroethane at low temperature yields a nitroalcohol which is oxidized to a ketone with Jones reagent. Reduction with sodium borotritide or borodeuteride and subsequent reduation of the nitro‐group and removal of blocking groups yields a phenethanolamine or α‐methylphenethanolamine labeled in the bensylic position. Preparation of deutero‐ and/or tritio‐labeled 2,4,5‐trihydroxyphenethylamine (6‐hydroxydopamine). α‐methyl‐6‐hydroxydopamine, α‐methyl‐p‐tyramine, β‐phenethanolamine. 2‐hydroxyphenethanolamine and α‐methyl‐4‐benzyloxyphenethanolamine is described.
Radiolysis of 14C‐ and 3H‐labelled thymidine
Authors: Kopoldová J. , Dedkǒvá V. 
Published: October 2006

Abstract10−3M oxygenated aqueous solutions of thymidine preparations, labelled with 14C and 3H in various positions were gammairradiated. Radiation produats formed were followed in dependenae of irradiation doses. Their yields were confronted with produats formed during the autoradiolysis of long time stored tritiated thymidine preparations, and results obtained Were disaussed.
The synthesis and purification of 8‐14C‐theophylline
Authors: Lohmann Suzanne M. , Miech Ralph P. 
Published: October 2006

AbstractThe enzymes responsible for the metabolism of methylated xanthines suah as theophylline, theobromine, and caffeine have until now escaped identification (1, 2). However, a sensitive radiometric method of analysis of theophylline metabolism (3) was made possible by the synthesis and purification of 8‐14C‐theophylline (14C‐Theo). 14C‐Theo was synthesized by the incorporation of 14C from 14C‐formic acid into the 8‐position of the purine ring. Purification of the 14C‐Theo was accomplished by subjecting the crude produot to cation‐exchange column chromatography with AG50W‐X12, 50–100 mesh resin of the hydrogen ion form.
Preparation du phenyl‐3 propene‐2 OL‐1 14C‐3 (alcool cinnamique 14C‐3)
Authors: Nguyen‐Hoang‐Nam  , Hoellinger H. , Pichat L. 
Published: October 2006

AbstractMethyl cinnamate ‐3‐14C is reduced smoothly in excellent yield to cinnamyl alcohol ‐3‐14C by aluminum hydride. without attack of the double bond. After purification by column chromatography cinnamyl alcohol ‐3‐14C is obtained with a radioactive overall yield of 65% based on cinnamic acid ‐3‐14C, specific activity = 9 mCi/mM.
An improved synthesis of 5‐fluorouracil‐6‐14C
Authors: Perry C. W. , Burger W. , Bader G. J. , Liebman A. A. 
Published: October 2006

AbstractUracil‐6‐14C (7). prepared in high radiochemical yield by conventional methods. has been converted to 5‐fluororacil ‐6‐14C (9) in over 90% yield using trifluoromethylhypofluorite. The use of this recently introduced reagent eliminates the necessity of preparing 9 from fluorinated precursors.
An optimized kinetics model for OH chemiluminescence at high temperatures and atmospheric pressures
Authors: Hall Joel M. , Petersen Eric L. 
Published: October 2006

AbstractChemiluminescence from the OH(A → X) transition near 307 nm is a commonly used diagnostic in combustion applications such as flame chemistry, shock‐tube experiments, and reacting‐flow visualization. Although absolute measurements of OH(X) concentrations are well defined, there is no elementary relation between emission from the electronically excited state (OH*) and its absolute concentration. Thus, to enable quantitative emission measurements, a kinetics model has been assembled and optimized to predict OH* formation and quenching at combustion conditions. Shock‐tube experiments were conducted in mixtures of H2/O2/Ar, CH4/O2/Ar, and CH4/H2/O2/Ar with high levels of argon dilution (>98%). Elementary reactions to model OH*, along with initial estimates of their rate coefficients, were taken from the literature. The important formation steps follow:

equation image

equation image

Sensitivity analyses were performed to identify experimental conditions under which the shape of the measured OH* profiles and the magnitude of the OH* emission would be sensitive to the formation reactions. A fitting routine was developed to express the formation rate parameters as a function of a single rate, k1 at the reference temperature (1490 K). With all rates so expressed, H2/CH4 mixtures were designed to uniquely determine the value of k1 at the reference temperature, from which the remaining rate parameters were calculated. Quenching rates were fixed at their literature values. The new model predicts the experimental data over the range of conditions studied and can be used to calibrate the emission diagnostic for other applications, such as measurements in real combustion environments, containing higher order hydrocarbon fuels and lower levels of dilution in air. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 714–724, 2006
Intramolecular carboxylic group‐assisted cleavage of N‐(2‐hydroxyphenyl)phthalamic acid (7) and N‐(2‐methoxyphenyl)phthalamic acid (8): Absence of intramolecular general acid catalysis due to 2‐OH in 7
Authors: Sim Yoke‐Leng , Ariffin Azhar , Khan M. Niyaz 
Published: October 2006

AbstractThe values of pseudo first‐order rate constants (kobs) for the cleavage of N‐(2‐hydroxyphenyl)phthalamic acid (7), obtained at 4.9 × 10−2 M HCl, 35°C, and within CH3CN content range 2–80% (v/v) in mixed aqueous solvent are smaller than kobs for the cleavage of N‐(2‐methoxyphenyl)phthalamic acid (8), obtained under almost similar experimental conditions, by nearly 1.5‐ to 2‐fold. These observations show the absence of expected intramolecular general acid catalysis due to 2‐OH group in 7. The values of kobs for the cleavage of 7 and 8 decrease by more than 20‐fold with the increase in the content of CH3CN from 2 to 80–82% (v/v) in mixed aqueous solvent. The kinetic data reveal that in acidic aqueous cleavage of 7, N‐cyclization (leading to the formation of imide) and O‐cyclization (leading to the formation of phthalic anhydride) vary from ∼10 to 15% and ∼90 to 85%, respectively, with the increase in CH3CN content from 2 to 80% (v/v). Similar increase in CH3CN content causes increase in N‐cyclization from ∼0 to 5% and decrease in O‐cyclization from ∼100 to 95% in the acidic aqueous cleavage of 8. Some speculative, yet conceivable, reasons for nearly 10 and 0% N‐cyclization in the cleavage of respective 7 and 8 at low content of CH3CN have been described. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 746–758, 2006
Decane oxidation in a shock tube
Authors: Olchanski Erna , Burcat Alexander 
Published: October 2006

AbstractThe ignition delay of n‐decane and oxygen diluted in argon was investigated for a series of mixtures ranging from 0.49 to 1.5% decane and 4.16 to 23.25% O2 diluted in argon. The temperature range was 1239–1616 K and the pressure range was 1.82–10.0 atm. All experiments were performed in a heated shock‐tube. An overall ignition delay equation was deduced for 144 experiments: τ = 10−12 exp(+34240/RT)[C10H22]0.60[O2]−1.305[Ar]0.08 s. Product distribution from preignition periods were measured. Detailed simulation schemes available in the literature were checked and a corrected model is proposed that fits well our experiments. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 703–713, 2006
Promotion of the fenton reaction by Cu2+ ions: Evidence for intermediates
Authors: Kremer Mordechai L. 
Published: October 2006

AbstractThe promotion of the Fenton reaction by Cu2+ ions has been investigated using a wide range of [Cu2+]. Both the disappearance of Fe2+ and the evolution of O2 were followed as a function of time by quenching the reaction mixture with o‐phenanthroline or with excess Fe2 + ions, respectively. Two series of experiments were performed. In one series [H2O2] was 5 × 10−4 mol dm−3, and in the other [H2O2] was reduced to 5 × 10−5 mol dm −3. By stopping the reaction with excess Fe2+ ions, significant differences in the measured absorbance in the two series were observed. In the higher [H2O2] range, the absorbance decreased monotonically in time, due to O2 formation during the reaction. In the lower range, an initial transient rise of the absorbance was observed, indicating the formation of spectroscopically distinct intermediates in the system. A mechanism involving the intermediates FeOCu4+ and FeOCu5+ has been set up. Rate constants of the mechanism have been determined. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 725–736, 2006
Kinetics of base hydrolysis of α‐amino acid esters catalyzed by the copper(II) complex of N,N,N′,N′‐tetramethylethylenediamine (Me4en)
Authors: Mohamed Mahmoud M. A. , Shoukry Azza A. , Shoukry Mohamed M. 
Published: October 2006

AbstractThe kinetics of base hydrolysis of glycine‐, histidine‐, and methionine methyl esters in the presence of [Cu‐Me4en]2+ complex is studied in aqueous solutions and in dioxane–water solutions of different compositions at T = 25°C and I = 0.1 mol dm−1. The kinetics of base hydrolysis of glycine and methionine methyl esters is studied at different temperatures. The kinetic data fits assuming that the hydrolysis proceeds in one step. The activation parameters for the base hydrolysis of the complexes are evaluated. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 737–745, 2006
FiberID—A technique to identify fibrous protein subclasses
Authors: Waltman Peter , Blumer Anselm , Kaplan David 
Published: October 2006

AbstractFibrous proteins such as collagen, silk, and elastin play critical biological roles, yet they have been the subject of few projects that use computational techniques to predict either their class or their structure. In this article, we present FiberID, a simple yet effective method for identifying and distinguishing three fibrous protein subclasses from their primary sequences. Using a combination of amino acid composition and fast Fourier measurements, FiberID can classify fibrous proteins belonging to these subclasses with high accuracy by using two standard machine learning techniques (decision trees and Naïve Bayesian classifiers). After presenting our results, we present several fibrous sequences that are regularly misclassified by FiberID as sequences of potential interest for further study. Finally, we analyze the decision trees developed by FiberID for potential insights regarding the structure of these proteins. Proteins 2007. © 2006 Wiley‐Liss, Inc.
Multiple Regression and Principal Component Analysis of Antibacterial Activities of Sulfones and Sulfonamides in Whole Cell and Cell‐Free Systems of Various DDS Sensitive and Resistant Bacterial Strains
Authors: Coats E. A. , Cordes H.‐P. , Kulkarni V. M. , Richter M. , Schaper K.‐J. , Wiese M. , Seydel J. K. 
Published: October 2006

AbstractAntibacterial effects of sulfones and sulfonamides have been determined in cell‐free folate synthesizing enzyme extracts and in whole cell cultures of various mycobacterial strains and E. coli sensitive and resistant to sulfones. Structural dependency of the observed activities has been quantitatively explained by multiple regression and principal component analysis. Both types of analyses lead to the same conclusion concerning the importance of electronic influences of substituents. In addition the influence of lipophilicity for the transport into the cells is demonstrated by the results of the PCA‐analysis. The importance of the results for the mode of action and the mechanism of resistance is discussed.
A Shape Index from Molecular Graphs
Authors: Kier Lemont B. 
Published: October 2006

AbstractA numerical index of molecular shape has been derived from the graph of the non‐hydrogen molecular skeleton. The index is based on the count of 2‐bond fragments in a graph relative to the maximum number possible in the isomeric star graph and the minimum number in the isomeric linear graph. In this initial study all non‐hydrogen atoms and all bonds are considered equal. The 2κ index describes the molecular shape in relationship to the star and linear graph and is normalized to the number of atoms. Applications are presented for shape similarity estimation, cavity filling ability and QSAR analyses.
QSAR for Cholinesterase Inhibition by Organophosphorus Esters and CNDO/2 Calculations for Organophosphorus Ester Hydrolysis
Authors: Johnson Howard , Kenley Richard A. , Rynard Carolyn , Golub Morton A. 
Published: October 2006

AbstractQuantitative structure‐activity relationships were derived for acetyl‐ and butyrylcholinesterase inhibition by various organophosphorus esters. Bimolecular inhibition rate constants correlate well with hydrophobic substituent constants, and with the presence or absence of cationic groups on the inhibitor, but not with steric substituent constants. CNDO/2 calculations were performed on a separate set of organophosphorus esters, RR′P(O)X, where R and R′ are alkyl and/or alkoxy groups and X is fluorine, chlorine or a phenoxy group. For each subset with the same X, the CNDO‐derived net atomic charge at the central phosphorus atom in the ester correlates well with the alkaline hydrolysis rate constant. For the whole set of esters with different X, two equations were derived that relate either charge and leaving group steric bulk, or orbital energy and bond order to the hydrolysis rate constant.
Co‐op students' access to shared knowledge in science‐rich workplaces
Authors: Munby Hugh , Taylor Jennifer , Chin Peter , Hutchinson Nancy L. 
Published: October 2006

AbstractWenger's (1998) concepts “community of practice,” “brokering,” and “transfer” explain the challenges co‐operative (co‐op) education students face in relating the knowledge learned in school with what they learn while participating as members of a workplace. The research for this paper is set within the contexts of the knowledge economy and increased collaboration in the workplace. The paper draws on several qualitative studies of work‐based education to examine the similarities and differences between learning in the workplace and learning in school, with a focus on science education and science‐rich workplaces. Barriers to connecting school knowledge and workplace knowledge include the nature of science (its purpose, accountability, and substance), the structure of knowledge in each setting, the form content knowledge takes, the sequence that the curriculum is presented in, and the gatekeeping that occurs when knowledge is accessed. The paper addresses implications for interventions in school and the workplace, with attention to the transition from school to work, and concludes by pointing to profound obstacles to connecting school knowledge with workplace knowledge. © 2006 Wiley Periodicals, Inc. Sci Ed 91:115–132, 2007
From an awareness of scientific data to concerns of mankind: Strategies for affective instruction in science
Authors: Baker Milton R. , Doran Rodney L. 
Published: October 2006

AbstractAnd God said, Let us make man in our image after our likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth.
Five years of achievement in ISCS
Authors: McDuffie Thomas E. , Derose James V. 
Published: October 2006

AbstractAchievement associated with a school district committed to the implementation of the Intermediate Science Curriculum Study (ISCS) materials and instructional strategy is the focus of this report. While ISCS is a three level, activity oriented, junior high program, the research was limited to the first year or Level I. Data were gathered from Level I students (mostly seventh graders) during a five year period. Analyses were per‐ formed to help answer questions such as: Are IQ and reading scores the highest correlates of achievement? Do IQ and reading correlates hold for both quantitative and qualitative indices of achievement? Do ISCS learning relationships hold over time? Are students able to evaluate how well they understand the concepts covered?
Science, stories, and sense‐making: A comparison of qualitative data from a wetlands unit
Authors: Hulland Carol , Munby Hugh 
Published: October 2006

AbstractPosner's theory of conceptual change forms the background for this study which focuses upon conceptual ecology, specifically upon the heuristics children appear to employ in sense‐making. The study reports data from a 2‐week wetland unit conducted during a summer camp program. The data consist of tape recordings and drawings made by the children. The analysis focuses upon two children who demonstrate remarkably different sense‐making heuristics: a recognizably scientific one and one that involves the generation of metaphors and personalized stories. The study argues the importance of attending to the heuristics of sense‐making in studies of conceptual ecology and conceptual change. © 1994 John Wiley & Sons, Inc.
Understanding a basic biological process: Expert and novice models of meiosis
Authors: Kindfield Ann C. H. 
Published: October 2006

AbstractCentral to secondary and college‐level biology instruction is the development of student understanding of a number of subcellular processes. Yet some of the most crucial are consistently cited as the most difficult components of biology to learn. Among these is meiosis. In this article I report on the meiosis models utilized by five individuals at each of three levels of expertise in genetics as each reasoned about this process in an individual interview setting. Detailed characterization of individual meiosis models and comparison among models revealed a set of biologically correct features common to all individuals' models as well as a variety of model flaws (i.e., meiosis misunderstandings) which are categorized according to type and level of expertise. These results are suggestive of both sources of various misunderstandings and factors that might contribute to the construction of a sound understanding of meiosis. Each of these is addressed in relation to their respective implications for instruction.