bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of tritiated juvenile hormones
Authors: Ajami Alfred M. , Crouse Dennis N. 
Published: October 2006

AbstractGeneral procedures for the tritiation of juvenile hormone analogues are described. Methyl epoxyfarnesoate, ethyl dichlorofarnesoate, epoxygeranyl‐p‐ethylphenyl ether, and ethyl 3,7,11‐trimethyl‐2, 4‐dodecadienoate were prepared with specific activities in the 50 mCi/mmole range by simple reactions that can be carried out directly in the biochemical laboratory without need for special equipment.
Ethynylation of 17‐oxo steroids labelled at position 16. synthesis of lynestrenol‐16‐3H at high specific activity
Authors: Broese A. I. A. , Favier J. S. , van Vliet N. P. , Warrell D. C. 
Published: October 2006

AbstractThe reaction of estr‐4–en‐17‐one‐16‐2H2 and 11α‐hydroxy‐estr‐4‐en‐17‐one‐16‐2H2 with potassium t‐butoxide and acetylene in tetrahydrofuran gave the 17α‐ethynyl‐17β‐ols with nearly complete loss of the label. Ethynylation with ethynyl magnesium bromide in tetrahydrofuran, however, proceeded with retention of the label. Application of the latter method to estrenone‐16‐3H (specific activity 14.0 Ci/mmol) gave lynestrenol‐16‐3H with a specific activity of 13.3 Ci/mmol.
Synthese de l'hydroxy‐9 ellipticine (14C‐1) ou hydroxy‐9 dimethyl‐5, 11 (6h) pyrido [4,3‐b] carbazole (14C‐1)
Authors: Van‐Bac Nguyen , Herbert Michel , Pichat Louis , Janot Maurice‐Marie , Dat‐Xuong Nguyen 
Published: October 2006

Abstract9‐Hydroxy‐ellipticine (14C‐1), specific activity: 2,13 mCi/mM, has been synthesized for molecular biology and cancer research, from N‐methyl‐formanilide (14C‐formyl). The radioactive overall yield was 13,5% based on sodium formate 14C.
Synthesis of labelled compounds for organic solid state self‐diffusion studies
Authors: Al‐Shaker M. Y. , Chadwick A. V. , Forrest J. W. 
Published: October 2006

AbstractThe synthesis and purification of radioactively labelled forms of hexamethyldisilane, norbornylene [bicyclo(2,2,1)‐hept‐2‐ene], norbornane [bicyclo (2,2,1)‐heptane] and tert‐butylmercaptan [2‐methyl‐2‐propanethiol] is described.
Synthesis of some 14C‐labelled isoxazole derivatives
Authors: Minato H. , Nagasaki T. , Katsuyama Y. 
Published: October 2006

AbstractIsoxazole derivatives, 3‐sulfanilamido‐5‐methylisoxazole (I) and 3,3‐dimethyl‐1‐(5‐methyl‐3‐isoxazolylcarbonyl)‐urea (II), have been labelled with carbon‐14. The carbon‐14 label was incorporated into the C‐5 of the isoxazole ring to give (I) and (II) in 22.3% and 33.0% radiochemical yield based on acetone‐14C, respectively.
Synthesis of stable isotope labeled norepinephrine
Authors: Murphy H. C. 
Published: October 2006

AbstractRacemic norepinephrine was synthesized with three deuterium atoms on the alkyl chain. The deuteration was accomplished by D/H exchange on the intermediate, dibenzylaminodihydroxyacetophenone, followed by reduction of the keto moiety and cleavage of the benzyl‐protecting groups with deuterium gas. Noradrenalone was also shown to be a possible intermediate for the incorporation of 180 into norepinephrine.
The preparation of 15N‐phenoxybenzamine
Authors: Mendelson W. L. , Weaner L. E. , Petka L. A. , Blackburn D. W. 
Published: October 2006

AbstractPhenoxybenzamine [N‐Bethyl‐N‐(l‐phenoxyisopropyl)‐2‐chloroethylamine hydrochloride] has been labelled with Nitrogen‐15 by a direct synthesis from 15N‐ammonium chloride. The isotopic enrichment was 92.8%.
Preparation of 2‐methylenebutanedioic acid‐4‐14C (itaconic acid)
Authors: Campbell D. R. 
Published: October 2006

AbstractThe pyrolysis of citric acid‐1, 5‐14C2 under controlled conditions and subsequent hydrolysis of the anhydride initially produced yields principally 2‐methylenebutanedioic acid‐4‐14C (citaconic acid‐14C), together with a minor amount of cis‐2‐methylbutenedioic acid‐4‐14C (citraconic acid‐14C). Comparison of the molar specific activities of the precursor and products indicates the absence of a carbon kinetic isotope effect in the decarboxylation‐dehydration reaction.
Synthesis of 2‐furanylmethyl‐α‐2H and ‐3H furosemide
Authors: Nelson W. L. , Wirth P. J. , Bettis C. J. , Spitznagle L. A. 
Published: October 2006

AbstractSynthesis of furosemide. specifically labelled at the 2‐furanylmethyl α‐position with 2H or 3H is reported. This synthesis required reduction of N‐[(2‐furanyhethyl)amino]‐4‐chloro‐5‐(N‐acetylaminosulfonyl)benzoia acid (2) with sodium 2H‐ or 3H‐borohydride. followed by alkaline hydrolysis of the acetyl group.
Synthesis of disodium D (‐)‐6‐(2‐phenyl‐2‐sulfoacetamido‐1‐14C) penicillanate (sulfocillln‐14C) and 6‐(2‐isobutyl‐β,γ‐3H2‐sulfo‐2‐phenylacetamido‐1‐14C) penicillanic acid (SP‐421‐3H, 14C)
Authors: Haayshi Nobuyoshi , Kato Shinji , Toga Tadashi , Nishijima Koji , Hanaoka Tadashi , Akimoto Hiroshi , Sugimoto Keiichi 
Published: October 2006

AbstractThe syntheses of disodium 6‐(2‐phenyl‐2‐sulfoacetamido‐1‐14C) peniaillanate (IV) and 6‐(2‐isobutyl‐β,γ‐ 3H2‐sulfo‐2‐phenyl‐acetamido‐1‐14C) penicillanic acid (XII) are described. The optically active D(‐)‐IV was obtained by the fractional crystallization of diastereoisomeric mixture which was prepared from phenylacetia acid‐1‐14C (I). The compound double labelled with 3H and 14C, XII, was synthesized by the reaction of trimethylsilyl 6‐aminopenicillanate with 2‐isobutyl‐β,γ‐3H2‐ sulfo‐2‐phenylacetyl chloride‐1‐14C (XI) which was prepared from isobutanol‐2,3‐3H2 and I. The overall radiochemical yields of XII, at the specific activities of 9 mCi (3H)/mmole and 2 mCi (14C)/mmole, were 34% yield based on isobutanol‐2,3‐3H2 and 17% yield based on I respeatively.
Synthesis of 14C‐ and 3H‐labelled 1,6–dimethyl‐3‐carbethoxy‐4‐oxo‐6,7,8,9‐tetrahydrohomo‐pyrimidazole salts
Authors: Bánfi D. , Volford J. , Mészáros Z. 
Published: October 2006

AbstractFor pharmacological investigations tetrahydrohomopyrimidazole salts were synthetized which were labelled by 14C and 3H isotopes in definite positions. The 1‐methyl‐14C, carbonyl‐14C, 3‐carbethoxyethyl‐14C, 1‐methyl‐3H 6,7,8,9‐3H and 3‐carbethoxyethyl‐3H‐homopyrimidazole isotope isomers were prepared.
Distribution of tritium label in Dl‐[G‐3H] phenylalanine
Authors: Clifford Merwyn C. , Evans E. Anthony , Kilner A. Edward , Warrell David C. 
Published: October 2006

AbstractThe position of the tritium label in DL‐[G‐3H] phenylalanine prepared by platinum catalysed exchange in tritiated water at elevated temperatures has been determined by chemical degradation and by tritium nuclear magnetic resonance speotroscopy. There is good agreement between the results of the two methods : analysis of the product of two separate preparations showing 73 ± 3% of the activity in the aromatic nucleus and 27 ± 3% in the side chain.
Preparation of tritium‐labeled 2, 4‐dichlorophenyl pyrrolidinecarboxylate
Authors: Hamada Masayuki , Shibata Setsuko , Kuwano Masataka , Suzuki Toshio 
Published: October 2006

Abstract2,4‐Dichlorophenol was labeled with tritium at 6 position by the catalytic reduction of 2,4‐dichloro‐6‐iodophenol. The condensation of 2,4‐dichlorophenol‐6‐3H with N‐chlorocarbamoylpyrrolidine produced 2,4‐dichlorophenyl pyrrolidinecarboxylate‐6‐3H. Distribution of tritium at 6 position in the 2,4‐dichlorophenol‐6‐3H was 95.9%.
A gas‐chromatographic method for the preparation of 14C‐labeled vinyl chloride
Authors: Wagner E. R. , Muelder W. M. , Watanabe P. G. , Hefner R. E. , Braun W. H. , Gehring P. J. 
Published: October 2006

AbstractA modification of our previously reported2 gas chromatographic method of preparing vinyl‐14C2 chloride (14C‐VC) has been made. The procedure using 1,2‐dichloroethane‐14C2 obtained from New England Nuclear Corporation gave good yields of 14C‐VC as a gas mixture with helium.The radiochemical purity of a representative sample of the 14C‐VC was determined by gas chromatography. Sequential fractions were trapped from gas chromatographic columns in a toluene based liquid scintillator. The radioactivity‐time profile was correlated with the retention time of authentic VC gas. A mass spectrum and a high resolution infrared spectrum obtained on the same sample of 14C‐VC were identical to spectra of authentic VC. The major radioactive impurity appeared to be acetylene.
Tritium recoil labeling of phenylacetic acid
Authors: Dubey Agnes , Castrillón José 
Published: October 2006

AbstractPhenylacetia acid has been labeled by means of the nuclear reaction 6Li(n,α)3H, both in mixture with Li2CO3 and as the lithium salt. The amount of Li2 CO3 was such as to keep the same weight ratio of lithium and phenylacetate ion as in the salt.It was observed that intimate mixtures of phenylacetic acid and lithium carbonate react slowly indicating that previous studies on the irradiation of mixtures of organic acids with lithium carbonate have not been performed with well defined systems.A considerably higher specific activity of the acid was found in the case of the irradiation of the lithium salt. A series of degradative reactions which insures a double determination for the activity at each molecular position was applied. In contradiction with previous results, it was observed that considerable labeling takes place at the α‐position; somewhat less for the salt. The overall picture is one of uniform labeling in both cases, in agreement with the lack of selectivity shown by hot atom reactions.
Synthesis of antheridiol‐(22,23‐3H)
Authors: McMorris Trevor C. , Arunachalam Thangavel 
Published: October 2006

AbstractAntheridiol‐(22,23‐3H) has been prepared by reduction of 3‐acetoxy‐23,23‐dihydroxy‐22‐oxo‐5, 24(28)‐ergostadiene‐28‐carboxylic acid gamma ‐ lactone with tritiated sodium borohydride followed by hydrolysis, photo‐oxygenation and cupric chloride catalysed rearrangement.
Effect of cytoplast on the development of inter‐subspecies nuclear transfer reconstructed goat embryo
Authors: Jian‐quan Chen , Juan Chen , Xu‐jun Xu , Guo‐hui Liu , Si‐guo Liu , Hong‐ying Sha , You‐bing Wu , Guo‐xiang Cheng 
Published: October 2006

AbstractThe aim of this study was to investigate effect of cytoplast on the development competence of reconstructed embryos derived from inter‐subspecies somatic cell nucleus transfer (SCNT). First, the development potency of reconstructed embryos produced by transferring Boer goat fibroblast cell nucleus of different ages into enucleated Sannen goat ova was evaluated in order to determine which age of nuclear donor is favorable for the reconstructed embryos development. Secondly, the another component of reconstructed embryos, “cytoplast,” was evaluated by comparing the effect of ovum cytoplast derived from Sannen ♂ × Boer ♀ descendant on the reconstructed embryos development to that of Sannen goat ovum cytoplast. The results revealed that the development rate of the reconstructed embryos derived from 2 months old Boer goat somatic cells was the highest, their gestation rate was up to 50%, and one viable male offspring was obtained. The cytoplast derived from the crossbreeding goats improves the development competence of reconstructed embryos, which birth rate was 5.5%. The genetic identification of offspring by using PCR‐SSCP analysis confirmed that these cloned kids were derived from the donor. The results above reveal that the cytoplast of Sannen goat ovum could induce the dedifferentiation of somatic cell nuclei derived from Boer goat, but the reprogramming process of these reconstructed embryos seems incomplete, probably due to some incorrect processes happened after implantation. Relatedness components of nucleus donor in cytoplast of the crossbreeding goat may be helpful to induce the dedifferentiation of somatic cell nuclei completely and improve the development competence of the reconstructed embryos. Mol. Reprod. Dev. 74: 568–573, 2007. © 2006 Wiley‐Liss, Inc.
Nonisothermal crystallization behavior of the poly(ethylene glycol) block in poly(L‐lactide)–poly(ethylene glycol) diblock copolymers: Effect of the poly(L‐lactide) block length
Authors: Yang Junliang , Zhao Ting , Cui Jijun , Liu Leijing , Zhou Yunchun , Li Gao , Zhou Enle , Chen Xuesi 
Published: October 2006

AbstractThe confined crystallization behavior, melting behavior, and nonisothermal crystallization kinetics of the poly(ethylene glycol) block (PEG) in poly(L‐lactide)–poly(ethylene glycol) (PLLA–PEG) diblock copolymers were investigated with wide‐angle X‐ray diffraction and differential scanning calorimetry. The analysis showed that the nonisothermal crystallization behavior changed from fitting the Ozawa equation and the Avrami equation modified by Jeziorny to deviating from them with the molecular weight of the poly(L‐lactide) (PLLA) block increasing. This resulted from the gradual strengthening of the confined effect, which was imposed by the crystallization of the PLLA block. The nucleation mechanism of the PEG block of PLLA15000–PEG5000 at a larger degree of supercooling was different from that of PLLA2500–PEG5000, PLLA5000–PEG5000, and PEG5000 (the numbers after PEG and PLLA denote the molecular weights of the PEG and PLLA blocks, respectively). They were homogeneous nucleation and heterogeneous nucleation, respectively. The PLLA block bonded chemically with the PEG block and increased the crystallization activation energy, but it provided nucleating sites for the crystallization of the PEG block, and the crystallization rate rose when it was heterogeneous nucleation. The number of melting peaks was three and one for the PEG homopolymer and the PEG block of the diblock copolymers, respectively. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3215–3226, 2006
Computational basis of knowledge‐based conformational probabilities derived from local‐ and long‐range interactions in proteins
Authors: Ormeci Lerzan , Gursoy Attila , Tunca Guzin , Erman Burak 
Published: October 2006

AbstractThe probabilities of the various basins in Ramachandran maps are examined critically. The theoretical basis of probability calculations both from molecular computations and from protein libraries are discussed. The well‐defined basins of the Ramachandran maps are treated as rotational isomeric states. Statistical independence and dependence of the states of different residues along the peptide chain are discussed. The Flory isolated pair hypothesis, near neighbor correlations, context effects, and long‐range correlations are examined critically. A method of evaluating long‐range correlations in helical and extended sequences is introduced in analogy with earlier polymer theory. Three different protein libraries are constructed where data is considered from residues in the (i) coiled regions, (ii) all regions, and (iii) only the helical and extended regions of proteins. Singlet and pairwise dependent probabilities calculated from these libraries are used to predict whether a given sequence is helical or extended. Predictions using pairwise dependence were not better than those using singlet probabilities. Modeling of long‐range correlations improved the predictions significantly. Removal of the Chameleon sequences from the data set also improved the predictions, but to a lesser extent. Proteins 2007. © 2006 Wiley‐Liss, Inc.
QSAR Analysis of the Subtilisin Hydrolysis of X‐Phenyl Hippurates
Authors: Carotti Angelo , Raguseo Cosima , Hansch Corwin 
Published: October 2006

AbstractThe hydrolysis of a set of 31 phenyl substituted hippurates by the enzyme subtilisin (Carlsberg, EC 3.4.21.3) was studied. The following quantitative structure‐activity relationship was formulated: log 1/Km = 0.41 σ + 0.20 MR4 + 0.19 π′3 + 3.81. In this expression, Km is the Michaelis constant, σ is the Hammett constant, MR4 is the molar refractivity of para substituents and π′3 is the hydrophobic parameter for meta substituents. π′3 applies only to the more hydrophobic of the two possible meta substituents.
Synthesis and Quantitative Structure‐Activity Relationship (QSAR) Analysis of Some Novel Yanthine Oxidase Inhibitors: 6‐(para‐substituted phenyl)‐pteridine‐4‐ones
Authors: Naeff Han S. D. , van Der Plas Henk C. , Tramper Johannes , Müller Franz 
Published: October 2006

AbstractA series of 6‐(p‐X‐phenyl)pteridine‐4‐ones (X=H (4a), F(4b), Cl (4c), Br (4d), I (4e), methyl (4f), ethyl (4g), n‐propyl (4h), i‐propyl (4i), t‐butyl (4j), methoxy (4k), n‐butyl (4l), and OH (4m)) was synthesized, and these compounds were then tested as inhibitors of xanthine oxidase. The compounds were synthesized by condensation of the 4,5‐diaminopyrimidine‐6‐one with the appropriate arylglyoxal in ethanol at ph 2.7; the resulting mixture of 6‐ and 7‐arylisomers of the pteridine‐4‐one was then separated by crystallization from dimethyl sulfoxide. Based on their Ki values when xanthine was used as a substrate, compounds 4a and 41 inhibited xanthine oxidase about 40 times more effectively than allopurinol, a well‐known inhibitor; when 7‐phenylpteridine‐4‐one was used as a substrate, 4a inhibited xanthine oxidase about 60 times more effectively than allopurinol. A quantitative structure‐activity relationship (QSAR) analysis of the compounds using the sterical parameters B1 and MR is presented. This analysis shows that, in contrast to spherical substituents, rod‐shaped substituents like n‐butyl do not reduce the effectiveness of inhibition.
An evaluation of the divergent physics laboratory
Authors: Lerch Robert D. 
Published: October 2006

AbstractDuring the school years 1969–1971, a set of objectives expressed by Dr. John M. Fowler of the Commission on College Physics was used to evaluate the divergent physics laboratories at New Mexico State University. The result indicated greater achievement of two of the objectives by students enrolled in divergent laboratories than by students enrolled in traditional laboratories. Additionally, the need for revising some elements of the divergent laboratory was indicated, as well as a need for special training of the graduate assistants who conducted the divergent laboratories.A synopsis of this paper was presented to the 14th Annual Idaho Academy of Science Meeting in April, 1972.
The relationship between visitor characteristics and learning‐associated behaviors in a science museum discovery space
Authors: Boisvert Dorothy Lozowski , Slez Brenda Jochums 
Published: October 2006

AbstractAs informal educational institutions, science museums must do more than entertain and amaze visitors. Museum educators must design exhibits that attract and hold the attention of visitors long enough so that the visitors become engaged with the exhibits and learn from them. In order for museum educators to develop such exhibits, more information is needed about the variables associated with learning in museums. This study contributes to the growing body of knowledge on informal education by examining the relationship between visitor characteristics and attraction, holding power, and visitor engagement.One hundred fifty‐four visitors to a science museum discovery space were observed as they interacted freely with the exhibits. Trained volunteers recorded the subjects' movements including the exhibits at which they stopped (attraction), the amount of time spent at each exhibit (holding power), and behaviors indicative of subjects' engagement levels with the exhibits. Data indicated significant differences between age group and the holding power of exhibits. Though not significant statistically, a similar trend was noted between age group and attraction and visitor engagement level. No significant differences were found between gender or social grouping and attraction, holding power, or engagement levels. © 1994 John Wiley & Sons, Inc.
Comparison of perceptions among rural versus nonrural secondary science teachers: A multistate survey
Authors: Baird William E. , Prather J. Preston , Finson Kevin D. , Oliver J. Steve 
Published: October 2006

AbstractA 100‐item survey was distributed to science teachers in eight states to determine characteristics of teachers, schools, programs, and perceived needs. Results from 1258 secondary science teachers indicate that they perceive the following to be among their greatest needs: (1) to motivate students to want to learn science; (2) to discover sources of free and inexpensive science materials; (3) to learn more about how to use computers to deliver and manage instruction; (4) to find and use materials about science careers; and (5) to improve problem solving skills among their students. Based on whether teachers classified themselves as nonrural or rural, rural teachers do not perceive as much need for help with multicultural issues in the classroom or maintaining student discipline as their nonrural peers. Rural teachers report using the following classroom activities less often than nonrural teachers: cooperative learning groups, hands‐on laboratory activities, individualized strategies, and inquiry teaching. More rural than nonrural teachers report problems with too many class preparations per day, a lack of career role models in the community, and lack of colleagues with whom to discuss problems. Among all secondary science teachers, the most pronounced problems reported by teachers were (in rank order): (1) insufficient student problem‐solving skills; (2) insufficient funds for supplies; (3) poor student reading ability; (4) lack of student interest in science: and (5) inadequate laboratory facilities. © 1994 John Wiley & Sons, Inc.
The development of science education in Botswana
Authors: Ogunniyi M. B. 
Published: October 2006

AbstractIn this article, an attempt has been made to describe the development of science education in Botswana. The argument has been that unlike most African countries, Botswana's relatively strong economy has had a salutory effect on the growth and development of science education in the country. Despite this positive setting, however, there are still obstacles standing in the way of the development of science education in the country. These obstacles have been discussed in terms of the nature of the education system, teachers' education, conditions of teaching and learning science, and the science curriculum. This article concludes by pointing out the irony inherent in an education system which limits access to higher education in science in the face of an acute shortage of scientific and technological personnel © 1995 John Wiley & Sons, Inc.
Tailoring science education graduate programs to the needs of science educators in low‐income countries
Authors: Lunetta Vincent N. , Berg Euwe Van Den 
Published: October 2006

AbstractScience education graduate programs in high‐income countries frequently enroll students from low‐income countries. Upon admission these students have profiles of knowledge, skills, and experiences which can be quite different from those of students from the host high‐income countries. Upon graduation, they will normally return to work in education systems with conditions which differ greatly from those in high‐income countries. This article attempts to clarify some of the differences and similarities between such students. It offers suggestions for making graduate programs more responsive to the special needs of students from low‐income countries and to the opportunities they offer for enhancing cross‐cultural sensitivity. Many of the suggestions can be incorporated within existing programs through choices of elective courses and topics for papers, projects, and research. Many references are provided to relevant literature on cultural issues and on science education in low‐income countries. © 1995 John Wiley & Sons. Inc.
Professional standards: An introduction and historical perspective
Authors: Mable Phyllis 
Published: October 2006

AbstractA collaborative profession‐wide effort has resulted in the establishment of professional standards of practice in student services and student development programs. These standards have the capacity to contribute in many ways to the improvement of undergraduate education. The standards recognize the value of out‐of‐class experience as a valid component of student development and have great utility for enhancing self‐study processes.