bluuebunny/crossref_metadata_2025 huggingface dataset:
Polyamino‐Substituted 1‐Oxa‐3,5‐diazahexatrienes and 1‐Oxa‐3,5,7‐triazaoctatetraenes (N‐Acyl‐oligocyanamides): Synthesis, Structures, Cyclovoltammetry and NLO Properties − Experiment and Theory
Authors: Möllers Christian , Prigge Jörg , Wibbeling Birgit , Fröhlich Roland , Brockmeyer Andreas , Schäfer Hans J. , Schmälzlin Elmar , Bräuchle Christoph , Meerholz Klaus , Würthwein Ernst‐Ulrich
Published: March 2003

A homologous series of N‐acylcyanamides of the formula R2N−[C(NMe2)=N]n−C(NMe2)=O with n = 1−3 has been prepared among similar amino‐substituted N‐acyl‐oligonitriles by treatment of guanidine 4 with carbamoyl chloride 5 yielding compound 6 (n = 1) and by ring opening of 1,3,5‐oxadiazinium salts 7 with morpholine (8) to give compounds 9 (n = 2) or with guanidine 4 to give compounds 10 (n = 3). The all‐dimethylamino‐substituted compound 10d reacts with ZnCl2 to yield a six‐membered chelate complex 10d·ZnCl2. The molecular structures of 9e,f, 10a−d and 10d·ZnCl2 have been elucidated by X‐ray crystallography and partly by DFT calculations. They deviate strongly from planarity with some examples showing helical structures. From the calculations, 10d is predicted to be a rather strong neutral base. One or two oxidation peaks, depending on the chain length, were observed by cyclic voltammetry. For the most extended derivative 10d a first oxidation potential of 1.12 V was measured. The molecular first hyperpolarizablities β0 were determined by hyper‐Rayleigh scattering (HRS) measurements. The β0 values increase with chain length and reach 5×10−30 esu for the longest derivative 10d. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Complexes of cadmium ion with guanine bases detected by electrospray ionization mass spectrometry
Authors: Moriwaki Hiroshi
Published: March 2003

The complexations of cadmium ion with guanine bases were detected by electrospray ionization mass spectrometry (ESI‐MS). In order to explore the toxicity of cadmium, such as oxidative stress to DNA and carcinogenesis, it is very important to determine the interactions between the cadmium ion and nucleotide. The analysis of mixed cadmium ion–guanosine aqueous solution (molar ratio 1 : 9) using ESI‐MS (cone voltage 20 V) showed the presence of various cadmium complex ions, such as [n (guanosine) + Cd]2+ (n = 3–8), [2guanine + Cd]2+, [guanosine + guanine + Cd]2+ and [guanosine + 2guanine + Cd]2+. The observed [2guanine + Cd]2+, [guanosine + guanine + Cd]2+ and [guanosine + guanine + Cd]2+ ions are formed through the dissociation of the N–glycoside bond at the interface of ESI‐MS. For deoxyguanosine and ethylguanine, similar cadmium complexes were observed. However, the complexes between the cadmium ion and 8‐hydroxydeoxyguanosine were not detected. Furthermore, when a higher molar ratio (Cd : guanosine) or cone voltage were used, more of the monovalent ion peaks, such as [Cd(guanine − H)2 + H]+ and [Cd(guanosine − H)2 + H]+, were observed and a decrease in the abundance of the divalent ions, such as [n(guanosine)+Cd]2+, occurred. Copyright © 2003 John Wiley & Sons, Ltd.
Toward the development of a standard e‐readiness assessment policy
Authors: Bakry Saad Haj
Published: March 2003

Information networking for digital integration is becoming of increasing importance for national and international organizations concerned with
development. E‐Readiness assessments, for various countries, are associated with the investigation of their state of readiness for such
integration. They help in understanding the problems that need to be resolved in order to avoid digital divide, or even digital isolation, from
world development. Such assessments lack standard policies, which provide unified measures that ease evaluations, support analysis and comparisons,
and help in diagnosing problems and deriving solutions. This paper is concerned with the development of a standard e‐readiness assessment
policy. It provides a base for the development of such a policy, and hopes that this base will contribute to a future standard international
policy. Copyright © 2003 John Wiley & Sons, Ltd.
Involvement of caveolin‐2 in caveolar biogenesis in MDCK cells
Authors: Lahtinen Ulla , Honsho Masanori , Parton Robert G. , Simons Kai , Verkade Paul
Published: March 2003

Caveolins have been identified as key components of caveolae, specialized cholesterol‐enriched raft domains visible as small flask‐shaped invaginations of the plasma membrane. In polarized MDCK cells caveolin‐1 and ‐2 are found together on basolateral caveolae whereas the apical membrane, where only caveolin‐1 is present, lacks caveolae. Expression of a caveolin mutant prevented the formation of the large caveolin‐1/‐2 hetero‐oligomeric complexes, and led to intracellular retention of caveolin‐2 and disappearance of caveolae from the basolateral membrane. Correspondingly, in MDCK cells over‐expressing caveolin‐2 the basolateral membrane exhibited an increased number of caveolae. These results indicate the involvement of caveolin‐2 in caveolar biogenesis.
The dihydroceramide desaturase is not essential for cell viability in Schizosaccharomyces pombe
Authors: Garton Sarah , Michaelson Louise V. , Beaudoin Frédéric , Beale Michael H. , Napier Johnathan A.
Published: March 2003

Recent studies have identified a new family of desaturase‐like polypeptide sequences in many higher eukaryotes. Functional characterisation of one member of this family, from Schizosaccharomyces pombe, revealed the enzyme to be a sphingolipid desaturase. This S. pombe gene designated SDCB3b8.07c was identified as the dihydroceramide Δ4‐desaturase, responsible for the synthesis of sphingosine. Homologous recombination was used to disrupt the endogenous S. pombe dihydroceramide Δ4‐desaturase. Surprisingly, this had no effect on cell viability, indicating that sphingosine may not be crucial for normal S. pombe functions. This observation has implications for our understanding of the role of sphingosine and its phosphorylated metabolite sphingosine‐1‐phosphate in lower eukaryotes.
EST analysis of gene expression in the tentacle of Cyanea capillata
Authors: Yang Yanzhen , Cun Shujian , Xie Xiaojin , Lin Jianghai , Wei Jianwen , Yang Wenli , Mou Chunyan , Yu Cuiling , Ye Lanting , Lu Yang , Fu Zhiyan , Xu Anlong
Published: March 2003

Jellyfish, Cyanea capillata, has an important position in head patterning and ion channel evolution, in addition to containing a rich source of toxins. In the present study, 2153 expressed sequence tags (ESTs) from the tentacle cDNA library of C. capillata were analyzed. The initial ESTs consisted of 198 clusters and 818 singletons, which revealed approximately 1016 unique genes in the data set. Among these sequences, we identified several genes related to head and foot patterning, voltage‐dependent anion channel gene and genes related to biological activities of venom. Five kinds of proteinase inhibitor genes were found in jellyfish for the first time, and some of them were highly expressed with unknown functions.
Key Events in the History of Electron Microscopy
Authors: Haguenau F. , Hawkes P.W. , Hutchison J.L. , Satiat–Jeunemaître B. , Simon G.T. , Williams D.B.
Published: March 2003

It is not easy to understand how the electron microscopes and electron
microscope techniques that we know today developed from the primitive ideas of
the first microscopists of the 1930s. Newcomers to the subject in particular,
their time almost fully occupied with grasping practical methods and modern
computing techniques, can rarely devote much attention to the history of their
subject. For some, however, this is a source of frustration: If a guide to the
principal stages in the development of the subject and to the main actors and
their publications were available, they would find the time to study it.
Editorial
Authors: Lyman Charles E.
Published: March 2003

Microscopy and Microanalysis has made significant strides
forward over the past year, and I would like to comment on two of
these. First, the Institute for Scientific Information (ISI) ranked
this journal third among the nine microscopy journals it indexes. The
ranking was in terms of ISI's Impact Factor, which tracks the
number of citations to papers published in the journal. A strong Impact
Factor indicates that information in the journal is of interest to
other workers in the field. Second, the National Library of Medicine
(NLM) has selected Microscopy and Microanalysis to be indexed
in MEDLINE (PubMed), beginning with the first issue of 2003. As any
biologist will tell you, this listing is essential for the electronic
visibility of papers in the fast-moving world of life sciences
research. I thank Editorial Board member Dave Piston for his efforts in
writing the initial letter of application to the NLM.
Food Insecurity and Hunger in the Kindergarten Classroom: Its Effect on Learning and Growth
Authors: Winicki Joshua , Jemison Kyle
Published: March 2003

This study investigates the correlation between food insecurity, educational achievement, and health among kindergarten children in the United States. Data from the Early Childhood Longitudinal Study—Kindergarten Cohort are used to analyze educational achievement and physical growth of kindergartners faced with food insecurity. The results demonstrate that children begin to experience the effects of food insecurity even at the most marginal level of household food deprivation. Children in households with any signs of food insecurity score lower and learn less during the school year.
Immigration Policy and Highly Skilled Workers: The Case of Japan
Authors: Fuess Scott M.
Published: March 2003

Concerned about shortages of highly skilled workers, especially those with international specialties, Japan adjusted its immigration policy in 1990. The government made it easier for skilled foreign specialists to work in Japan. In the wake of the policy adjustment, this study examines whether there have been changes in inflows of skilled foreigners. Though Japan is still wary of immigration and official policy remains comparatively strict, it is clear that skilled professionals are entering Japan in larger numbers.
Policy Issues of China's Urban Unemployment
Authors: Song Shunfeng
Published: March 2003

This article investigates causes and characteristics of urban layoff and unemployment. Chinese statistics show that the worsening urban unemployment problem is mainly caused by China's institutional changes, sectoral shifts, and cyclical fluctuations. Workers who are middle‐aged, less educated, and female have experienced a higher risk of being laid off and unemployed. This article also discusses policy issues of China's urban layoff and unemployment. Supply‐side policies include those that expand education, establish job‐training programs, limit massive rural–urban migration in the short run, and rationalize labor force participation rate. Demand‐side policies aim to create jobs, including policies such as promoting the service industry, attracting foreign investment, and developing the nonstate economy.
Hepatoprotective Activity of Reduohanxiao-tang (Yuldahanso-tang) is Related to the Inhibition of β-Glucuronidase
Authors: Bae Hyung-Sup , Kim Young-Suk , Cho Ki-Ho , Lee Kyung-Sup , Kim Jung-Jin , Lee Hae-Ung , Kim Dong-Hyun
Published: March 2003

β-Glucuronidase-inhibitory and hepatoprotective effects of Reduohanxiao-tang (Yuldahanso-tang), which has been used for liver diseases and stroke, on carbon tetrachloride (CCl4)-induced hepatotoxicity of rats were investigated. Reduohanxiao-tang potently inhibited β-glucuronidases. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactic acid dehydrogenase (LDH) levels of the CCl4 group orally treated with Reduohanxiao-tang (100 mg/kg) were lowered to 54%, 71.5% and 66.1% of the CCl4-treated control group, respectively. Among the ingredients of the Reduohanxiao-tang, the rhizomes of Pueraria thunbergiana and it Scutellaria baicalensis potently inhibited β-glucuronidases and protected against CCl4-induced liver injury. Orally administered puerarin, which is a main component of Pueraria thunbergiana, showed potent hepatoprotective activity, but did not inhibit β-glucuronidase. However, daidzein, which is produced from puerarin by human intestinal bacteria, potently inhibited β-glucuronidase. These results suggest that β-glucuronidase inhibition by herbal medicines may protect a gainst CCl4-induced liver injury.
MAPPING OF SUB-WATERSHEDS FROM DIGITAL ELEVATION MODEL: A MORPHOLOGICAL APPROACH
Authors: CHOCKALINGAM L. , DAYA SAGAR B. S.
Published: March 2003

This short note presents an application of an algorithm to extract two singular networks of topological interest, such as channel and ridge connectivity networks, from a contour based Digital Elevation Model (DEM) of a region with hilly terrain. From these two extracted networks, a sub-watershed map of this region has been automatically generated. This study facilitates in understanding the watershed morphological processes in a firm quantitative manner in discrete space.
Focal adhesion kinase: the first ten years
Authors: Parsons J. Thomas
Published: March 2003

The protein tyrosine kinase focal adhesion kinase (FAK) plays a prominent role in integrin signaling. FAK activation, demonstrated by an increase in phosphorylation of Tyr397 as well as other sites in the protein, is best understood in the context of the engagement of integrins at the cell surface. Activation of FAK results in recruitment of a number of SH2-domain- and SH3-domain-containing proteins, which mediate signaling to several downstream pathways. FAK-dependent activation of these pathways has been implicated in a diverse array of cellular processes, including cell migration, growth factor signaling, cell cycle progression and cell survival.
Stereoselective Isomerization of Tetrakistrifluoromethyl Tetraaryl [4]Radialenes to the Type II (All-Z) Isomers
Authors: Uno Hidemitsu , Nibu Nobumasa , Yamaoka Youtarou , Mizobe Noboru
Published: March 2003

Coupling reaction of 2-aryl-1,1-dibromo-3,3,3-trifluoropropenes using zinc and copper(I) bromide gave [4]radialenes in almost statistic ratios in addition to [3]cumulenes. Thermal dimerization of the cumulenes in neat gave mixtures of four isomeric [4]radialenes in moderate yields. When the isomers were heated in solid at appropriate temperatures, thermal isomerization occurred to afford type II (all-Z) isomers of [4]radialenes in high selectivity.
1,2,3,5,7-Pentaselena-4,6,8-triphosphocane as the Revised Structure for “3,4,5-Triselenoxo-1,2-diselena-3,4,5-triphospholane” Determined by X-Ray Analysis
Authors: Yoshifuji Masaaki , Higeta Naru , An De-Lie , Toyota Kozo
Published: March 2003

The structure of a new type of phosphorus-selenium containing eight-membered heterocyclic compound, 1,2,3,5,7-pentaselena-4,6,8-triphosphocane, was unambiguously determined by the X-ray analysis as the revised structure for the 3,4,5-triselenoxo-1,2-diselena-3,4,5-triphospholane, which had been previously proposed as a selenation reagent of amides to selenoamides.
Radical Anions of Oligogermanes, Me(Me2Ge)nMe (n=2,3,5, and 10) Generated by Pulse Radiolysis
Authors: Mochida Kunio , Hata Rieko , Chiba Hiromi , Seki Shuhei , Yoshida Yohichi , Tagawa Seiichi
Published: March 2003

Radical anions of permethylated oligogermanes, Me(Me2Ge)nMe (n=2,3,5, and 10) by pulse radiolysis technique showed two transient absorption bands in the UV-Vis and NIR regions. Their absorption maxima shifted to longer wavelengths with increasing the Ge-Ge chain in the permethylated oligogermanes.
Synthesis of ZnO Nanoparticles by Decomposition of Zinc Peroxide
Authors: Uekawa Naofumi , Kajiwara Jyunichi , Mochizuki Naomi , Kakegawa Kazuyuki , Sasaki Yoshinori
Published: March 2003

Zinc peroxide sols were prepared by the peptization of Zn(OH)2 using 1 mol/L of H2O2 aqueous solution at 348 K for 2 h. Firing the dried sol powder at 573 K for 2 h formed almost monodispersed ZnO nanoparticles whose average diameter was 19 nm.
Synthesis and Characterization of Novel Ligands 1,2-Bis(salicylideneaminooxy)ethanes
Authors: Akine Shigehisa , Taniguchi Takanori , Nabeshima Tatsuya
Published: March 2003

Novel ligands 1,2-bis(salicylideneaminooxy)ethanes were synthesized. They were much more stable against exchange reactions of aldehyde units than the corresponding salen derivatives. They form stable complexes with a copper(II) ion, whose structures were crystallographically determined. Spectroscopic and electrochemical studies indicated that the complexes have lower LUMO levels than salen analogues.
Synthesis of Orthorhombic LiMnO2 Material and Its Optimization
Authors: Lee Yun Sung , Sun Yang Kook , Yoshio Masaki
Published: March 2003

Orthorhombic LiMnO2 was synthesized using LiOH and γ-MnOOH at 1000 °C in the argon flow by quenching method. X-ray diffraction revealed that the LiMnO2 showed a well-defined orthorhombic phase of a space group with Pmnm. The lattice constants were a = 2.806 Å, b = 5.750 Å, and c = 4.593 Å. The LiMnO2 after grinding delivered 212 mAh/g in the 9th cycle and still delivered 200 mAh/g after 50 cycles at room temperature. The well-defined orthorhombic LiMnO2 by the quenching method exhibited an excellent cycle performance.
Hydrodechlorination of Trichloromethane to Higher Hydrocarbons over Pd/SiO2 Catalyst
Authors: Mori Tohru , Kikuchi Takashi , Kubo Jun , Morikawa Yutaka
Published: March 2003

Pd/SiO2 catalyzed C–C bond formation selectively to give C2–C7 hydrocarbons in the hydrodechlorination of CHCl3. The produced hydrocarbons followed well the Schultz–Flory distribution, indicating that the hydrocarbons were formed via polymerization of surface C1 species such as methylene group.
Wechselwirkungen mit aromatischen Ringen in chemischen und biologischen Erkennungsprozessen
Authors: Meyer Emmanuel A. , Castellano Ronald K. , Diederich François
Published: March 2003

Zwischenmolekulare Wechselwirkungen unter Beteiligung aromatischer Ringe sind Schlüsselvorgänge sowohl in chemischen als auch in biologischen Erkennungsprozessen. Ihr Verständnis ist für das rationale Wirkstoffdesign und für die Leitstrukturoptimierung in der Medizinischen Chemie essenziell. Unterschiedliche Ansätze werden für ein tiefergehendes Verständnis der strukturellen und energetischen Parameter einzelner Erkennungsarten mit aromatischen Substraten verfolgt: erwähnt seien biologische Untersuchungen, Studien der molekularen Erkennung mit künstlichen Rezeptoren, Suchen in kristallographischen Datenbanken, Gasphasenstudien und theoretische Untersuchungen. Dieser Aufsatz versucht, diese Wissensgebiete zu vereinen und die aus zahlreichen Untersuchungen gewonnenen Erkenntnisse zusammenzufassen. Er widmet sich hauptsächlich Beispielen mit biologischer Relevanz mit dem Ziel, die für die Wirkstoffentwicklung wichtigen Kenntnisse der molekularen Erkennung zu vertiefen.
Short communication: Thermal stability of the diazohydroborate [1‐N2B10H9]−: degradation to [B20H18]2− anion
Authors: Naoufal Daoud , Bonnetot Bernard , Mongeot Henri
Published: March 2003

The thermal stability of the monodiazohydroborate NMe4[1‐N2B10H9] was studied by thermogravimetric analysis. Under two different atmospheres (air and argon), the thermal decomposition starts at a temperature between 140 and 160 °C. The decomposition residue obtained was separated on a silica gel column. 11B NMR, IR and electrospray mass spectroscopy analyses of the different fractions separated showed that the above decomposition produces (NMe4)2[B20H18] as major product (90%), along with smaller amounts of residual NMe4[1‐N2B10H9] (5%), (NMe4)2[B12H12] and boric acid. Copyright © 2003 John Wiley & Sons, Ltd.
Differentiating sex offences: a behaviorally based thematic classification of stranger rapes
Authors: Canter David V. , Bennell Craig , Alison Laurence J. , Reddy Steve
Published: March 2003

It is hypothesized that stranger rape victim statements will reveal a scale of violation experienced by the victim, ranging from personal violation, through to physical violation, and finally, at the most extreme level, sexual violation. It is also hypothesized that offences can be differentiated in terms of one of four themes: hostile, controlling, stealing, or involving. To test these hypotheses, crime scene data from 112 rapes were analyzed by the multi‐dimensional scaling procedure Smallest Space Analysis. The results provide empirical support for a composite model of rape consisting of four behavioral themes as different expressions of various intensities of violation. The results also suggest that stranger rapes may be less about power and control than about hostility and pseudo‐intimacy. The proposed model has implications for the classification of rape, the investigation of sexual crimes, and the treatment of victims. Copyright © 2003 John Wiley & Sons, Ltd.
Structural, Photophysical, and Electrophosphorescent Properties of Platinum(II) Complexes Supported by Tetradentate N2O2 Chelates
Authors: Lin Yong‐Yue , Chan Siu‐Chung , Chan Michael C. W. , Hou Yuan‐Jun , Zhu Nianyong , Che Chi‐Ming , Liu Yu , Wang Yue
Published: March 2003

We present an examination of the structural and photophysical characteristics of [Pt(N2O2)] complexes bearing bis(phenoxy)diimine auxiliaries (diimine=4,7‐Ph2phen (1) and 4,4′‐tBu2bpy (2)) that are tetradentate relatives of the quinolinolato (q) ligand. These neutral derivatives display high thermal stability (>400 °C in N2). While the crystal lattice in 1 consists of (head‐to‐tail)‐interacting dimers, molecules of 2 are arranged into infinitely stacked planar sheets with possible π–π interactions but no close Pt⋅⋅⋅Pt contacts. Complexes 1 and 2 exhibit moderately intense low‐energy UV/Vis absorptions around λ=400–500 nm that undergo negative solvatochromic shifts. Both derivatives are highly luminescent in solution at 298 K with emission lifetimes in the μs range, and mixed 3[l→π*(diimine)] (l=lone pair/phenoxide) and 3[Pt(d)→π*(diimine)] charge‐transfer states are tentatively assigned. The excited‐state properties of 2 are also investigated by time‐resolved absorption spectroscopy and by quenching experiments with pyridinium acceptors to estimate the excited‐state redox potential. These emitters have been employed as electrophosphorescent dopants in multilayer OLEDs. Differences between the brightness, color, and overall performance of devices incorporating 1 and 2 are attributed to the influence of the diimine substituents.
Shape and Symmetry of Heptacoordinate Transition‐Metal Complexes: Structural Trends
Authors: Casanova David , Alemany Pere , Bofill Josep M. , Alvarez Santiago
Published: March 2003

The stereochemistries of heptacoordinate transition‐metal complexes are analyzed by using continuous symmetry and shape measures of their coordination spheres. The distribution of heptacoordination through the transition‐metal series is presented based on structural database searches including organometallic and Werner‐type molecular complexes, metalloproteins, and extended solids. The most common polyhedron seems to be the pentagonal bipyramid, while different preferences are found for specific families of compounds, as in the complexes with three or four carbonyl or phosphine ligands, which prefer the capped octahedron or the capped trigonal prism rather than the pentagonal bipyramid. The symmetry maps for heptacoordination are presented and shown to be helpful for detecting stereochemical trends. The maximal symmetry interconversion pathways between the three most common polyhedra are defined in terms of symmetry constants and a large number of experimental structures are seen to fall along those paths.
Characterization of the 310‐Helix in Model Peptides by HRMAS NMR Spectroscopy
Authors: Lancelot Nathalie , Elbayed Karim , Raya Jésus , Piotto Martial , Briand Jean‐Paul , Formaggio Fernando , Toniolo Claudio , Bianco Alberto
Published: March 2003

A tetra‐ and a hepta‐homopeptide from the Cα‐tetrasubstituted Aib (α‐aminoisobutyric acid) residue were covalently linked to the POEPOP resin by the fragment‐condensation approach. The conformational preferences of the two model peptides were determined for the first time on a solid support by means of high‐resolution magic angle spinning NMR spectroscopy. The results obtained indicate that the Aib homopeptides adopt a regular 310‐helical structure even when they are covalently bound to a polymeric matrix, and thus confirm the remarkable conformational stability of the peptides rich in this amino acid. An ATR‐FTIR spectroscopic investigation, performed in parallel, also confirmed that these polymer‐bound peptides do indeed adopt a helical conformation. The results of this study open the possibility to exploit the peptide‐resin conjugates based on Cα‐tetrasubstituted α‐amino acids as helpful, structurally organized templates in molecular recognition studies or as catalysts in asymmetric synthesis.
Observations on the Synthesis of Photochromic Naphthopyrans
Authors: Gabbutt Christopher D. , Heron B. Mark , Instone Alicia C. , Thomas David A. , Partington Steven M. , Hursthouse Michael B. , Gelbrich Thomas
Published: March 2003

1‐Naphthol reacts with 1,1‐diarylprop‐2‐yn‐1‐ols 5a,b, under alumina catalysis, by two pathways to give the photochromic naphtho[1,2‐b]pyrans 6a,b, together with the propenylidenenaphthalenones 7a,b, representatives of a new class of merocyanine dyes. With 2‐methyl‐1‐naphthol, formation of the photochrome is suppressed; the only products are merocyanines 7c,d. The cyclocondensation of 2‐naphthol with 5a,b proceeds much more efficiently, to give the naphtho[2,1‐b]pyrans 14a,b. Pyran formation is not suppressed from either 1‐bromo‐ or 1‐(4‐methoxyphenyl)‐2‐naphthol; reaction with 5a,b merely results in expulsion of the C‐1 substituent. An alternative pathway supervenes in the reaction of 1‐methyl‐2‐naphthol with 5a to give the benz[e]indanone 17, the constitution of which was determined by X‐ray crystallography. Reaction of the 1,3,3‐triarylpropynols 19a,b with 1‐naphthol affords the naphthopyrans 20 together with merocyanines 21, whilst the isomeric pyrans 23 are efficiently produced from 2‐naphthol. The configuration of merocyanines 7a and 21a was unequivocally established by X‐ray crystallography. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Screening, library‐assisted identification and validated quantification of fifteen neuroleptics and three of their metabolites in plasma by liquid chromatography/mass spectrometry with atmospheric pressure chemical ionization
Authors: Kratzsch Carsten , Peters Frank T. , Kraemer Thomas , Weber Armin A. , Maurer Hans H.
Published: March 2003

A liquid chromatographic/mass spectrometric assay with atmospheric pressure chemical ionization (APCI‐LC/MS) is presented for the fast and reliable screening and identification and for the precise and sensitive quantification of 15 neuroleptic (antipsychotic) drugs and three of their relevant metabolites in plasma. It allows confirmation of the diagnosis of a neuroleptic overdose and monitoring of psychiatric patients' compliance. The neuroleptics amisulpride, bromperidol, clozapine, droperidol, flupenthixol, fluphenazine, haloperidol, melperone, olanzapine, perazine, pimozide, risperidone, sulpiride, zotepine and zuclopenthixol and the pharmacologically active metabolites norclozapine, clozapine N‐oxide and 9‐hydroxyrisperidone were extracted from plasma using solid‐phase extraction and were separated on a Merck LiChroCART column with Superspher 60 RP Select B as the stationary phase. Gradient elution was performed using aqueous ammonium formate and acetonitrile. After screening and identification in the scan mode using the authors' new LC/MS library, the neuroleptics were quantified in the selected‐ion mode. The quantification assay was fully validated. It was found to be selective and proved to be linear from sub‐therapeutic to over therapeutic concentrations for all analytes. The corresponding reference levels are listed. The accuracy and precision data were within the required limits. The analytes were stable in frozen plasma for at least 1 month. The method was successfully applied to several authentic plasma samples from patients treated or intoxicated with various neuroleptics. The validated LC/MS assay has proved to be appropriate for the isolation, separation, screening, identification and quantification of various neuroleptics in plasma for clinical toxicology and therapeutic drug monitoring purposes. Copyright © 2003 John Wiley & Sons, Ltd.
Aligned Nafion® Nanocomposites: Preparation and Morphological Characterization
Authors: Karthikeyan C. S. , Schossig M. , Radovanovic E. , Gonçalves M. C. , Wittich H. , Schulte K. , Nunes S. P.
Published: March 2003

A novel nanocomposite based on Nafion® (ionomer) and a layered silicate is studied. An innovative approach of processing a composite under electric field to induce orientation of the inorganic filler was carried out and accomplished in the present work. The morphology of oriented composites was analyzed by scanning electric potential microscopy (SEPM) and transmission electron microscopy (TEM). Films based on both plain ionomer and composite displayed fine contrast in SEPM, differentiating the phases, which could not be achieved using conventional atomic force microscopy. The orientation of the silicates in the composites is evident from the SEPM picture.

AFM of Nafion®/montmorillonite composite films prepared by solution casting under electric field (Image obtained by SEPM).

magnified image

AFM of Nafion®/montmorillonite composite films prepared by solution casting under electric field (Image obtained by SEPM).
Functional role of sperm surface glutathione S‐transferases and extracellular glutathione in the haploid spermatozoa under oxidative stress
Authors: Hemachand T. , Shaha Chandrima
Published: March 2003

On the sperm surface, glutathione S‐transferases (GSTs) exist as oocyte binding proteins but their detoxification function in this unique cell type is not known. Using H2O2‐ and 4‐hydroxynonenal‐induced sperm dysfunction models, this study demonstrates that the sperm surface GSTs are able to use extracellular reduced glutathione to inhibit the loss of functional competence of goat spermatozoa; however, in the presence of GST inhibitors, they are unable to do so. In the context of susceptibility of spermatozoa to oxidative stress, this finding that strategically located sperm surface GSTs are important for maintaining the functional competence of sperm is relevant to studies on male infertility.
Developmental regulation of β‐1,3‐galactosyltransferase‐1 gene expression in mouse brain
Authors: Zhu Dan , Shen Aiguo , Wang Ying , Gu Xiaosong , Gu Jianxin
Published: March 2003

β‐1,3‐galactosyltransferase‐1 (β3GalT‐1) is the key enzyme to form the type 1 chain structure. Northern blot analysis indicated that β3GalT‐1 was expressed predominantly in the brain. In the present study, it was revealed that the gene expression of β3GalT‐1 in mouse brain was developmentally decreased. High expression levels of β3GalT‐1 were found in cerebral cortex and hippocampus in both newborn and adult mice, while in cerebellum, the expression levels decreased markedly during development. In situ hybridization revealed that the absence of expression in cerebellar granual cell layers contributed to the main loss of β3GalT‐1 expression in adult mouse cerebellum. Moreover, the decreased levels of β3GalT‐1could affect the synthesis of type 1 chain oligosaccharides, as revealed by immunohistochemistry analysis.
GENERALIZED QUASI-COHERENT SHEAVES
Authors: ENOCHS E. , ESTRADA S. , GARCÍA-ROZAS J. R. , OYONARTE L.
Published: March 2003

The category of quasi-coherent sheaves on the projective line P1(k) (k is a field) is equivalent to certain representations of the quiver • → • ← •. Many of the techniques which are used to study these sheaves apply to more general categories. We give the definitions of these more general categories and then consider one particular such category in depth. In this particular category we prove that there are no (nonzero) projective representations but that the category admits flat covers (or, equivalently in this situation, torsion free covers) and cotorsion envelopes.
CENTRAL IDEMPOTENTS IN THE RATIONAL GROUP ALGEBRA OF A FINITE NILPOTENT GROUP
Authors: JESPERS ERIC , LEAL GUILHERME , PAQUES ANTONIO
Published: March 2003

We describe the primitive central idempotents of a rational group algebra of a finite nilpotent group. The description does not make use of the character table of the group G.
Intramolecular Spin Interactions through Cumulative Double Bonds
Authors: Yamagata Takehiro , Tukada Hideyuki , Kobayashi Keiji
Published: March 2003

Cumulative double bonds were proved to act as a ferromagnetic spin coupler between both sides of π-conjugated spins, as investigated by temperature dependence of quintet ESR signals of three isomeric dinitrene species in which two spin centers are incorporated in a tetraphenylallene framework.
Surface Plasmon Resonance Study on the Interaction of Immobilized Macrocyclic Sugar Clusters with Lectins and Water-soluble Polymers
Authors: Hayashida Osamu , Shimizu Chikao , Fujimoto Tokako , Aoyama Yasuhiro
Published: March 2003

A surface plasmon resonance study indicates that an amphiphilic calix[4] resorcarene derivative having eight polar side chains with terminal galactose or glucose residues and four long alkyl chains are immobilized on a hydrophobic sensor chip; the resulting monolayer of the sugar moieties, exposed to the bulk aqueous phase, binds lectin polysaccharides, and ploy(vinylalcohol) in water.
Ionic Conductivity of Molten Salts Formed by Polyether/salt Hybrids
Authors: Ohno Hiroyuki , Nakai Yoshikazu , Ito Kaori
Published: March 2003

PEO oligomers having sulfonamide groups or ethylimidazolium groups on the chain ends were prepared, and they were mixed to form molten salts at the terminal of these PEO derivatives. For the PEO having sulfonamide groups, it glass transition temperature decreased from 3.2 °C to −61.6 °C and ionic conductivity increased about 105 times after mixing with PEO having ethylimidazolium groups. The formation of molten salts at the terminal of PEO chains is effective for the design of fast ion transfer matrix.
Correlation of the Frontier Orbital Properties of Alkanolamines with the Experimental CO2 Loading
Authors: Suda Taiichiro , Zhang Yan , Iwaki Toru , Nomura Masakatsu
Published: March 2003

The HOMO energy and the superdelocalizability for the most stable conformation of 18 kinds of alkanolamines plotted against experimentally measured absorption loading of CO2 in an aqueous amine solution showed a good linear relationship for the usual secondary and tertiary amines, indicating that the frontier orbital properties of these amines appear to be predominant for the amine-CO2 reaction.
First Evidence of Polyimide Elastomer Prepared from Polyurea and Pyromellitic Dianhydride
Authors: Asai Kiyotsugu , Onouchi Yukio , Inoue Shin-ichi , Okamoto Hiroshi
Published: March 2003

The reaction of polyureas, prepared from the conventional diisocyanates and the α,ω-diaminopolyoxyalkylenes, with pyromellitic dianhydride in N-methyl-2-pyrolidone (NMP) at 165 °C leads to the formation of polyimide elastomers. The polyimide elastomers exhibited excellent physical properties.
Stacking of Poly(3-alkylthiophene)s and Poly(4-alkylthiazole)s in a Colloidal Solution and in the Solid
Authors: Yamamoto Takakazu , Komarudin Dharma , Kubota Kenji , Sasaki Shintaro
Published: March 2003

Regioregular poly(3-hexylthiophene-2,5-diyl) and poly(4-heptylthiazole-2,5-diyl) form colloidal solutions in CHCl3-CH3OH mixtures; light scattering analysis and filtration experiments reveal that about 103 molecules of stiff poly(3-hexylthiophene-2,5-diyl) aggregate in a side-to-side stacking mode. The two polymers and related polymers are stacked in an end-to-end or interdigitation mode in the solid.
Studies on the Interaction of DNA and a Novel of Water-soluble Polymer-bound Schiff Base Complex
Authors: Wang Yun-Pu , Xiao Yao-Nan , Wang Rong-Min , Mao Ying
Published: March 2003

The modes and activities of the interaction of DNA and water-soluble polymer bound Schiff base nickel complex, which has been prepared by polymer analogous reaction, have been discussed according to fluorescent probe method. It indicates that polymer matrix effect and increasing solubility in water can increase the interaction of this polymer complex with DNA.
Barbier-type Carbonyl-allylation with Allyl Compounds and SnCl2 in the Presence of PdCl2[PPh2(m-C6H4SO3Na)]2 under Two-phase Conditions
Authors: Okano Tamon , Kiji Jitsuo , Doi Takanori
Published: March 2003

The hydrophilic palladium complex efficiently catalyzes the allylation of carbonyl compounds with allyl chlorides or allyl alcohols and SnCl2 under aqueous-organic biphase conditions, which allow us easily to separate the product and to recover the organic solvent from the reaction mixture.
Selective Removal of Cobalt Oxide from Cobalt-loaded Alumina Catalysts and Its Effect on the Activity for Selective Catalytic Reduction of Nitrogen Monoxide by Ethene in Excess Oxygen
Authors: Okazaki Noriyasu , Tsuda Shinya , Shiina Yoshikazu , Akio Tada
Published: March 2003

The selective removal of Co3O4 from a cobalt-loaded alumina catalyst resulted in increased activity for the title reaction, indicating that Co3O4 inhibited the reaction but that the resudual CoAl2O4-like species acted as catalytically active species. CoAl2O4-like species were sufficiently active for the oxidation of NO to NO2 but much less active for the oxidation of ethene (a side reaction).
Meso-meso Linked Diporphyrins from 5,10,15-Trisubstituted Porphyrins
Authors: Yoshida Naoya , Shimidzu Hitoshi , Osuka Atsuhiro
Published: March 2003

Meso-meso coupled diporphyrins were prepared from 5,10,15-trisubstituted zinc-porphyrins in high yields upon treatment with AgPF6 alone or with AgPF6 and I2.
Fractionation of Lithium Isotopes by Intercalation in Layered Inorganic Ion Exchangers
Authors: Makita Yoji , Kanoh Hirofumi , Hirotsu Takahiro , Ooi Kenta
Published: March 2003

Layered titanium phosphates and heat-treated tin phosphate showed high separation factors (1.015-1.018) for lithium isotopes; the fractionation properties could be explained by considering two factors: the degree of Li+ dehydration in the solid phase and the affinity of the ion-exchange site toward Li+.
Rhodium-catalyzed Conjugate Addition of Arylstannanes to α,β-Unsaturated Ketones and Esters
Authors: Oi Shuichi , Moro Mitsutoshi , Ono Sachie , Inoue Yoshio
Published: March 2003

Aryltrimethylstannanes react with α,β-unsaturated ketones and esters in the presence of a catalytic amount of a cationic rhodium complex, [Rh(cod)(MeCN)2]BF4, affording the conjugate addition products in good yields.
Surface Alkylation of Hydrogenated Amorphous Silicon by Grignard Reagent
Authors: Ehara Takashi , Maruyama Arata
Published: March 2003

Surface alkylation of hydrogenated amorphous silicon thin films has been achieved by Grignard reaction. IR absorption spectra indicate the existence of C–H bonds that are due to covalent bonded decyl group on the surface of amorphous silicon. This modification can be a first step of novel organic–inorganic interface formation.
Transparent, Adhesive Film Formation of Per-O-valeryl-β-cyclodextrin
Authors: Hirayama Fumitoshi , Zaoh Katutoshi , Harata Kazuaki , Saenger Wolfram , Uekama Kaneto
Published: March 2003

Per-O-valeryl-β-cyclodextrin forms a transparent, adhesive sheet-like film on water surface and on backing membrane, without any chemical crosslinkings.
Analysis of the Complex of Oligonucleotide Duplexes with Ligands by MALDI-TOF Mass Spectroscopy
Authors: Yamashita Kenichi , Sato Shinobu , Takamiya Hiroki , Takagi Makoto , Takenaka Shigeori
Published: March 2003

The peaks for a complex of DNA-interacting ligands naphthalene monoimide (NMI), naphthalene diimide (NDI) and ethidium bromide and groove binding ligand Hoechst 33258 with a duplex of oligonucleotide 5′-CCCCGGGG-3′ were observed successfully in MALDI-TOF mass spectroscopy. The appearance of the peak of the complex depended on both the binding mode (classical intercalation, threading intercalation, or groove binding) and the duplex structure (fully matched or mismatched).
Synthesis and Mesomorphic Properties of Liquid Crystals with a 5,5′-Bitropolone Skelton
Authors: Kubo Kanji , Sutoh Takanori , Mori Akira , Ujiie Seiji
Published: March 2003

New troponoid liquid crystals with a bitropolone core were prepared. The ester derivatives (1) had enantiotropic smectic A and/or C phases with higher thermal stabilities than the corresponding benzenoid derivatives (2), which had smectic B phases. X-ray diffraction studies revealed that the layer spacings of the smectic A and C phases were not so much different.
A Good Performance VPO Catalyst for Partial Oxidation of n-Butane to Maleic Anhydride
Authors: Wang Xiaoshu , Nie Weiyan , Ji Weijie , Guo Xuefeng , Yan Qijie , Chen Yi
Published: March 2003

A VPO catalyst prepared by the reaction of vanadium pentoxide and isobutyl alcohol/benzyl alcohol in the presence of polyethylene glycol with the molecular weight of 2000 (PEG2000) was found to be highly selective and active for the conversion of n-butane to maleic anhydride.
Zinc Bromide-Promoted Tosylation of Alcohols Allows Efficient Temperature-Controlled Primary Hydroxy Sulfonylation
Authors: Yamamura Hatsuo , Kawasaki Jyumpei , Saito Hirokazu , Araki Shuki , Kawai Masao
Published: March 2003

The combination of zinc bromide with tosyl chloride promoted sulfonylation, allowing temperature-controlled regioselective sulfonylation of carbohydrates which possess both primary and secondary hydroxy groups.
Catalytic and Stereoselective Glycosylation with Disarmed Glycosyl Fluoride Having Phthaloyl or Dichlorophthaloyl Protected Amino Function Using a 1 : 2 Combination of Stannic Chloride and Silver Tetrakis(pentafluorophenyl)borate
Authors: Jona Hideki , Maeshima Hisashi , Mukaiyama Teruaki
Published: March 2003

A catalytic and stereoselective glycosylation of various glycosyl acceptors with disarmed glycosyl fluorides having phthaloyl or dichlorophthaloyl protected amino function is successfully carried out by using a combination of stannic chloride (SnCl4) and silver tetrakis(pentafluorophenyl)borate [AgB(C6F5)4] in the coexistence of MS 5A, and the corresponding 1,2-trans disaccharides are obtained in high yields.
Influence of Ethylamine on the Crystal Growth of Hydroxyapatite Crystals
Authors: Nagata Fukue , Toriyama Motohiro , Teraoka Kay , Yokogawa Yoshiyuki
Published: March 2003

The ability of ethylamine to influence hydroxyapatite (HAp) crystal growth has been studied. HAp crystals were obtained from the mixture of HAp precursor slurry and various amount of ethylamine under hydrothermal condition. The products synthesized with 5 wt% or more ethylamine were plate-like crystals whose grown face was a-plane of HAp. Several analyses suggested that the role of ethylamine was the inhibition of crystal growth along a particular axis.
Formation of Silver Nanoparticles in Poly(methyl methacrylate) by UV Irradiation
Authors: Yanagihara Naohisa , Tanaka Yoshiyuki , Okamoto Hiroshi
Published: March 2003

Silver nanoclusters in poly(methyl methacrylate) (Ag/PMMA) were prepared by bulk polymerization of MMA with radical initiators (AIBN or BPO) in the presence of silver(I) trifluoroacetate, followed by a period of UV irradiation. It was revealed that any of Ag/PMMA samples prepared by both the initiators shows a plasmon absorption peak at ca. 420 nm, whereas an additional peak at ca. 340 nm was found exclusively for those samples prepared in the presence of BPO.
Fabrication of a Stable Nanostructured Ternary Composite Film via Different Driving Forces
Authors: Cao Tingbing , Cao Weixiao
Published: March 2003

Three characteristic macromolecules have been combined to fabricate muitilayer ultra-thin film with different driving forces of electrostatic interaction and hydrogen bonding attraction, under UV irradiation, both the ionic bond and H-bond between the layers were converted into covalent bond, and the multilayer film becomes very stable towards polar solvents.
Hydrogelation of Calcium Metaphosphate Glass
Authors: Kasuga Toshihiro , Wakita Takashi , Nogami Masayuki , Sakurai Makoto , Watanabe Makoto , Abe Yoshihiro
Published: March 2003

A calcium phosphate hydrogel with high viscosity was easily derived for a brief period from the reaction of water with the metaphosphate glass powders. 31P MAS-NMR and HPLC spectra showed that the hydrogel has linear and cyclic polyphosphate structures consisting of PO4 group connected to calcium ions and protons with hydrogen-bonded water molecules.
Synthesis and Characterization of a Novel Charge Transfer Compound with Large Three-Photon Absorption Cross Section
Authors: Zhang Junxiang , Cui Yiping , Wang Mingliang , Xu Chunxiang , Zhong Yuan , Liu Juzheng
Published: March 2003

A new intramolecular charge transfer compound containing diethylamino group as electronic donor and oxadiazole group as electronic acceptor has been synthesized using Wittig–Horner reaction. This long conjugated molecule has large three-photon absorption cross section excited at 1.06 μm lasing.
Cooperative Effect of a Metal Ion and Hydrogen Bonds on Phosphodiester Cleavage in Acetonitrile
Authors: Kondo Shin-ichi , Sakuno Yuichi , Yokoyama Takashi , Yano Yumihiko
Published: March 2003

Cleavage of an activated phosphodiester by Zn(NO3)2·6H2O was accelerated (9 × 103-fold) by cooperative effect of a metal ion and hydrogen bonds in the presence of a bismelamine derivative bearing a 2,2′-bipyridine moiety in MeCN.
Surface-Enhanced Raman Scattering of Single Adenine Molecules on Silver Colloidal Particles
Authors: Maruyama Yoshihiro , Ishikawa Mitsuru , Futamata Masayuki
Published: March 2003

To find feasibility of identifying nucleotides at the single-molecule level, we implemented Raman imaging and spectroscopy of adenine molecules adsorbed on Ag colloidal nanoparticles. Surface enhanced Raman scattering (SERS) of adenine molecules showed an intermittent on-and-off behavior called “blinking”. The observation of blinking provides substantial evidence for detecting single adenine molecules.
CO2 Hydrogenation to Alcohols over Highly Dispersed Co/SiO2 Catalysts Derived from Acetate
Authors: Okabe Kiyomi , Yamada Hidekazu , Hanaoka Takaaki , Matsuzaki Takehiko , Arakawa Hironori , Abe Yoshimoto
Published: March 2003

Highly dispersed Co(A)/SiO2 catalysts were prepared from acetate, and used for CO2 hydrogenation to alcohols under the reaction conditions of T = 493 K, P = 2.1MPa, H2/CO2 = 3/1, and GHSV = 2000 h−1. Catalytic activity was greatly improved by adding a small amount of Ir to the catalyst, and methanol (ca. 20%) was formed, in contrast with Co(N)/SiO2 catalyst derived from nitrate. Ethanol selectivity was increased up to 8% by adding Na salt to the Ir/Co(A)/SiO2 catalyst.
Quantitative Evaluation of Lewis Acidity of Zinc Ion with Tetradentate Tripodal Ligands in Formation of the Superoxide Complexes
Authors: Ohtsu Hideki , Fukuzumi Shunichi
Published: March 2003

A series of Zn(II)–superoxide complexes containing tetradentate tripodal ligands are generated in the reactions between Zn(II) complexes and superoxide which is produced by the photoinduced reduction of dioxygen by dimeric 1-benzyl-1,4-dihydronicotinamide. The Zn(II)–superoxide complexes have been characterized spectroscopically in order to evaluate the Lewis acidity of Zn(II) ion depending on the ligands used as Cu,Zn–SOD models.
Nitrous Oxide Oxidation of Secondary and Benzylic Alcohols Using Ruthenium Complex Catalyst
Authors: Hashimoto Kentaro , Kitaichi Yasunori , Tanaka Hirotaka , Ikeno Taketo , Yamada Tohru
Published: March 2003

Catalytic N2O oxidation of various secondary and benzylic alcohols using a ruthenium porphyrin complex is presented. Both secondary and benzylic alcohols were smoothly consumed to give the corresponding ketones and aldehydes in high yields. Nitrous oxide (N2O) is expected to be a new terminal oxidant producing only dinitrogen gas as the only by-product to provide a less wasteful process.