bluuebunny/crossref_metadata_2025 huggingface dataset:
Human α-defensin regulates smooth muscle cell contraction: a role for low-density lipoprotein receptor–related protein/α2-macroglobulin receptor
Authors: Nassar Taher , Akkawi Sa'ed , Bar-Shavit Rachel , Haj-Yehia Abdullah , Bdeir Khalil , Al-Mehdi Abu-Bakr , Tarshis Mark , Higazi Abd Al-Roof
Published: November 2002

We have previously identified α-defensin in association with medial smooth muscle cells (SMCs) in human coronary arteries. In the present paper we report that α-defensin, at concentrations below those found in pathological conditions, inhibits phenylephrine (PE)–induced contraction of rat aortic rings. Addition of 1 μM α-defensin increased the half-maximal effective concentration (EC50) of PE on denuded aortic rings from 32 to 630 nM. The effect of α-defensin was dose dependent and saturable, with a half-maximal effect at 1 μM. α-Defensin binds to human umbilical vein SMCs in a specific manner. The presence of 1 μM α-defensin inhibited the PE-mediated Ca++ mobilization in SMCs by more than 80%. The inhibitory effect of α-defensin on contraction of aortic rings and Ca++ mobilization was completely abolished by anti–low-density lipoprotein receptor–related protein/α2-macroglobulin receptor (LRP) antibodies as well as by the antagonist receptor-associated protein (RAP). α-Defensin binds directly to isolated LRP in a specific and dose-dependent manner; the binding was inhibited by RAP as well as by anti-LRP antibodies. α-Defensin is internalized by SMCs and interacts with 2 intracellular subtypes of protein kinase C (PKC) involved in muscle contraction, α and β. RAP and anti-LRP antibodies inhibited the binding and internalization of α-defensin by SMCs and its interaction with intracellular PKCs. These observations suggest that binding of α-defensin to LRP expressed in SMCs leads to its internalization; internalized α-defensin binds to PKC and inhibits its enzymatic activity, leading to decreased Ca++mobilization and SMC contraction in response to PE.
Researchable questions to support evidence-based mental health policy concerning adult mental illness
Authors: Thornicroft Graham , Bindman Jonathan , Goldberg David , Gournay Kevin , Huxley Peter
Published: November 2002

Policy makers find much mental health research irrelevant to their concerns. What types of research would directly assist those who formulate policy? The two purposes of this paper are (i) to identify important gaps in completed research, particularly in relation to the National Service Framework (NSF) for Mental Health (Department of Health, 1999a) and the NHS Plan (NHS Confederation, 2001); and (ii) to translate these gaps into researchable questions that can contribute to a debate about the future research agenda for general adult mental health in England.
Audit of transfers under the Mental Health Act from prison – the impact of organisational change
Authors: Isherwood Sarah , Parrott Janet
Published: November 2002

AIMS AND METHOD

To describe the change in the number of referrals of prisoners and the delay in transfer to hospital under the Mental Health Act following a change in the prison health care provision. The transfer time (time from referral to transfer to psychiatric hospital) of prisoners has been audited previously over 1996 and 1997.

RESULTS

There has been an increase in the number of prisoners transferred. Both transfers under Section 48 of the Mental Health Act and the proportion of transfers to high security have increased. The average delay in transfer remains lengthy and there is a trend of increasing delay with increasing level of placement security.

CLINICAL IMPLICATIONS

Despite Government policies to facilitate the transfer of mentally disordered offenders, we found an increase in the delay to hospital compared with previous audits.
Where are the weakest links?: a descriptive study of discrepancies in prescribing between primary and secondary sectors of mental health service provision
Authors: Morcos Salwa , Francis Sally-Anne , Duggan Catherine
Published: November 2002

AIMS AND METHOD

To investigate the transfer of information regarding prescribed medication between primary and secondary care sectors. Patients aged 18–65 years, ready for discharge from hospital, were invited to participate. Prescribed medication was recorded from their hospital and general practitioner records. The significance of discrepancies identified between medication lists was assessed independently by four judges.

RESULTS

Discrepancies occurred for 39 out of 43 patients at each stage of medication information transfer. Discrepancies at the time of admission and following discharge occurred in 69% and 43%, respectively, of drugs studied. It was judged that harm would occur to the patient, should the discrepancy be reproduced, in 24% and 18%, respectively, of cases.

CLINICAL

IMPLICATIONS Discrepancies in the transfer of information regarding prescribed medication may result in harm to patients.
Specialist registrars' views on the proposed reform of the Mental Health Act (1983)
Authors: Spencer Maya , Gregoire Alain
Published: November 2002

AIMS AND METHOD

A postal questionnaire was sent to specialist registrars (SpRs) in the Wessex Region to evaluate senior trainees' reactions to information about the proposed changes in mental health legislation and to ascertain if the information had adversely affected their view of their future careers as consultants.

RESULTS

A high level of concern about the proposed changes and their potential impact on consultants was revealed. A majority of SpRs took a more negative view of their future career, especially those preparing a single Certificate of Completion of Specialist Training in general adult psychiatry, who were more likely to have adverse perceptions and to have thought of opting out.

SERVICE IMPLICATIONS

The legislative proposals have the potential for considerable impact on recruitment and retention of psychiatrists.
Do we listen or do we assume?
Authors: Potter Robert , Holmes Patricia , Barton Hilary
Published: November 2002

AIMS AND METHOD

To use a questionnaire to assess and compare what referred children and their referrers would like from a multi-disciplinary post-abuse service based in Bridgend, South Wales.

RESULTS

It was found that the children and their referrers wanted different types of support and help from the service. Specifically, children wanted to be ‘listened to’ on an individual basis and to talk about the effect of their distressing experiences on their lives, but they did not want to talk about the details of the abuse and did not want to be blamed. Referrers wanted more practical help for the children.

CLINICAL IMPLICATIONS

The study highlights the need to listen to what the child wants from a post-abuse service rather than assuming that this is already known by the referrer or the therapist. It will also help referrers to think clearly about reasons for referral.
Acute wards: problems and solutions
Authors: Haigh Rex
Published: November 2002

In 1953 the World Health Organization produced a report dealing with ‘essential mental hospital provisions'. The report emphasised the importance of the atmosphere of the hospital:

‘The most important single factor in the efficacy of the treatment given in a mental hospital appears to the Committee to be an intangible element which can only be described as its atmosphere, and in attempting to describe some of the influences which go to the creation of this atmosphere, it must be said at the outset that the more the psychiatric hospital imitates the general hospital as it at present exists, the less successful it will be in creating the atmosphere it needs. Too many psychiatric hospitals give the impression of being an uneasy compromise between a general hospital and a prison. Whereas, in fact, the role they have to play is different from either; it is that of a therapeutic community’ (World Health Organization, 1953)
Acute wards: problems and solutions
Authors: Holmes Jeremy
Published: November 2002

There has been a curious linguistic shift in the use of the word community in mental health (Holmes, 2001a). In the 1950s and early 1960s community psychiatry was synonymous with milieu therapy and the therapeutic community – that is, the attempt to create a vibrant community of patients and staff, in a shared space, working actively together to overcome disability, illness and stigma. The contrast was with insitutional psychiatry, caricatured as the silent, soulless and, at times, abusive wards of the Victorian mental hospital. The therapeutic community had two main psychotherapeutic tools: group therapy and creative therapies such as art therapy and psychodrama. These approaches were pioneered in specialist units such as the Henderson hospital (Norton & Haigh, 2002) but, more generally, progressive acute units emphasised the use of ward groups and the importance of patients playing an active part in decision-making.
Acute wards: problems and solutions
Authors: Davenport Sarah
Published: November 2002

This paper describes rehabilitation principles and some specialised practice that could usefully inform the provision of acute in-patient care. A low secure rehabilitation setting is described using a method of case formulation to embed an envelope of care around an individual patient within a therapeutic ward milieu. This increases the collaboration and transparency around individual care planning and the capacity for self-reflection within the multi-disciplinary team, in a manner that may be applicable to other in-patient settings.
Service innovations: rethinking in-patient provision for adolescents
Authors: Corrigall Richard , Mitchell Bryn
Published: November 2002

AIMS AND METHOD

To evaluate the first 2 years of a new adolescent unit.

RESULTS

One-hundred and eighteen cases were admitted, with a broad range of diagnoses. Median length of stay was 33 days and 82% of admissions were urgent, of which 70% were admitted on the day of referral. A later study of 27 consecutive cases showed a mean improvement of 25% in the Children's Global Assessment Scale and 40% in the Child and Adolescent version of the Health of the Nation Outcome Scales scores.

CLINICAL IMPLICATIONS

It is possible to provide an in-patient service for adolescents that includes all-hours emergency access, as well as catering for the full range of severe mental illness and a wide variation in length of stay.
Clean and secure energy for the twenty-first century
Authors: Fells I
Published: November 2002

“As energy demand world-wide continues to rise, fuelling the expanding economy, the twin problems of security of supply and rising carbon dioxide emissions have risen high in the global agenda. Can economic growth be sustained without increasing energy demand? Is the prospect of global warming and the destabilisation of the weather machine so daunting that a global carbon tax should be instituted? Can renewable energy replace fossil fuel in the next 50 years? Will nuclear energy re-emerge as the high technology solution to our problems?”
Performance improvements of the recuperated gas turbine cycle using absorption inlet cooling and evaporative aftercooling
Authors: Bassily A. M.
Published: November 2002

An absorption inlet cooling system is introduced into the recuperated gas turbine cycle. The exhaust gases of the cycle are used to run the system. Five different layouts of the recuperated gas turbine cycle are presented. These include the effects of absorption inlet cooling, evaporative inlet cooling and evaporative cooling of compressor discharge (evaporative aftercooling), and the combined effect of absorption inlet cooling and evaporative aftercooling. A parametric study of the effect of pressure ratio, ambient temperature and relative humidity on the performance of all cycles is carried out. The results indicate that absorption inlet cooling could increase the efficiency of the recuperated cycle by up to 4 per cent, compared with 2.2 per cent for evaporative inlet cooling. Absorption inlet cooling with evaporative aftercooling could increase the optimum per efficiency of the recuperated cycle by up to 5 per cent and its maximum power by up to 65 per cent. Evaporative aftercooling reduces the impact of inlet cooling. Another parametric study of the effect of the turbine compressor inlet temperature ratio on the optimum pressure ratios indicated that cycles with evaporative aftercooling have higher optimum pressure ratios, which could be a function of the inlet temperature ratio and air temperature at the compressor outlet.
A centrifugal compressor stage with wide flow range vaned diffusers and different inlet configurations
Authors: Kim Y , Engeda A , Aungier R , Amineni N
Published: November 2002

In most cases, the diffuser system of a centrifugal compressor comes in the two general categories of a vaneless or a vaned diffuser. The vaned diffuser can generally be subdivided into two types depending on channel geometry (straight or curved channel) or depending on solidity. For the three different vaned diffusers of a centrifugal compressor stage, the design procedure is presented and experimental data are compared. The primary objective of the diffuser design was to achieve substantial improvement, compared with the stage currently used for the intended application, for the stable operating flow range as well as for the head rise from design to surge flow. The design goals also included achieving competitive efficiency levels, which required a significant efficiency improvement. Test results showed a much wider stable operating range than had been expected. This stage operated well beyond the expected vaned diffuser stall limit. The inlet configuration and inlet flow structure are known significantly to affect the compressor performance. Each of the three diffusers is tested for two different types of inlet configuration, and the relative performances are assessed.
Thermodynamic analysis of the rotary tooth compressor
Authors: Peng X , Xing Z , Li L , Shu P
Published: November 2002

The Roots blower has no built-in compression and therefore is not efficient when it discharges gases at pressures substantially higher than at suction. The rotary tooth compressor, which includes built-in compression, has been proposed as a more efficient alternative. This paper describes an analytical study of the rotary tooth compressor. A mathematical model has been constructed to simulate the thermodynamic processes within it and hence predict its performance. The model allows for gas leakage as well as the main gas flow into and out of the working chamber. The estimated performance has been compared with experimental test results. The mathematical model was thereby validated. Further analyses were then carried out, using the validated mathematical model, to determine the magnitude of power and capacity losses in the machine. It is shown that the rotary tooth compressor is more efficient than the Roots blower at pressure ratios greater than about 1.4. Loss in capacity is most affected by gas leakage, and the main cause of loss in adiabatic efficiency is the power loss associated with high gas velocities during discharge.
A review of closed valve head prediction methods for centrifugal pumps
Authors: Dyson G
Published: November 2002

A review of the available methods used to predict the closed valve head of a centrifugal pump is presented. A database of pump geometry was assembled and used to assess the methods of prediction for accuracy on the basis of their specific speed and configuration. The methods based only on Euler correction factors are found to be the least accurate and give an indication of the possible closed valve head value within 20 per cent. Further methods linked to the geometry through empirical coefficients prove more successful. Correction coefficients are suggested that improve the accuracy of the prediction methods for the analysed pumps within the database.
Stereodynamics of O(1D) and O(3P) Reactions Studied via Doppler-Resolved Polarization Spectroscopy
Authors: Fujimura Yo , Tsurumaki Hiroshi , Kajimoto Okitsugu
Published: November 2002

Studies on stereodynamics of the gas-phase elementary reactions of atomic oxygen, O(1D) and O(3P), with simple molecules are reviewed. The angular correlations among the relative velocity vectors of reactants (k) and products (k′), and the product rotational angular momentum vector (j′) have been investigated via Doppler-resolved polarization spectroscopy. In the O(1D) reactions with hydrocarbons and water, OH products are scattered into wide angular range and rotate mainly in the k–k′ scattering plane. These angular distributions suggest the formation of an H–O–X (X = C or O) bond in reactive intermediates. By contrast, the NO products of the O(1D) reaction with N2O have isotropic angular distribution of j′, which indicates the participation of the out-of-plane motion in addition to the in-plane motions within the complex. These trends of O(1D) reactions are consistent with the feature of product-state distribution of the individual reactions. Similar analyses for the reactions of O(3P) atom with hydrocarbons have revealed that these reactions are not always dominated by the simple rebound abstraction mechanism based on the triatomic picture, which has long been assumed. As a background of the titled study, this account reviews the progress in the studies on gas-phase chemical reaction dynamics and presents the theory and techniques to investigate the stereodynamics of bimolecular reactions.
Bioorganic Studies on Nyctinasty of the Plant Controlled by a Biological Clock
Authors: Ueda Minoru , Takada Noboru , Yamamura Shosuke
Published: November 2002

Most leguminous plants close their leaves in the evening, as if to sleep, and open them early in the morning. This circadian rhythm is known to be controlled by the biological clock of such plants. Extensive studies on other nyctinastic plants led to the isolation of a variety of leaf-closing and leaf-opening substances. And we found that the circadian rhythmic leaf-movement of these plants is controlled by a biological clock that regulates the balance of concentration between leaf-opening and -closing substances.
Functionalization of Inorganic Colloidal Particles by Polymer Modification
Authors: Yoshinaga Kohji
Published: November 2002

The polymer modifications of inorganic colloidal particles, mainly silica, and the stabilization and functionalization were described. The polymer grafting procedures on colloidal silica via covalent bond bindings in order to stabilize and functionalize were presented along with the modification of inorganic particle powder. In the modifications, the reaction of the surface hydroxy groups with polymeric trialkoxysilane was effective for grafting the polymer in terms of controlling the attachment and of successive introduction of functional groups. Especially, the grafting of poly(maleic anhydride-co-styrene) (P(MA-ST)) onto colloidal silica by the reaction with P(MA-ST)-trimethoxysilane gave stable and dispersible composite particles (P(MA-ST)/SiO2) in organic solvent. The introduction of secondary polymer to P(MA-ST)/SiO2 successfully controlled the dispersion in organic solvent and ζ-potential in aqueous or highly polar solvents. The modification of colloidal titania with Ru(II)-(2,2′-bipyridyl) complex-tethered polymer gave a photo-active catalyst that exhibited photoinduced electron transfer to a donor by visible light irradiation. Moreover, colloidal crystallization was observed in the suspension of monodisperse, polymer-modified silica in organic solvent, which was a good polar solvent for grafted polymer. The colloidal crystallization of the modified silica took place through close-packing under the electrostatic repulsion among the particles, as well as the crystallization of unmodified silica in aqueous solution.
Facile Formation of Stable Crystals with Gold-like Metallic Luster from Organic Molecules: 1-Aryl-2-(2-thienyl)-5-[5-(tricyanoethenyl)-2-thienyl]pyrroles
Authors: Ogura Katsuyuki , Zhao Rui , Yanai Hiroyuki , Maeda Kazuhiro , Tozawa Ryo , Matsumoto Shoji , Akazome Motohiro
Published: November 2002

The derivatives of 1-phenyl-2-(2-thienyl)-5-[5-(tricyanoethenyl)-2-thienyl]pyrrole (1a) formed crystals with gold-like or bronze-like metallic luster. When a small substituent is located at the para position of the 1-phenyl group, gold-like lustrous crystals were formed. In contrast, the derivatives of 1 having a longer alkyl chain at the para position of the 1-phenyl group gave bronze-like crystals. The gold-like lustrous crystals have a sheet structure. In the sheet, the molecules of 1 are close to each other via the intermolecular interaction of cyano nitrogen with the hydrogen of the nearest thiophene or pyrrole ring, which enables the side-by-side interaction of the cyano group with the nearest thiophene and pyrrole rings. The bronze-like crystals have a lamella structure of the long alkyl chains that is sandwiched by two π-electron walls. In the wall, the 2-(2-thienyl)-5-[5-(tricyanoethenyl)-2-thienyl]pyrrole moieties are arranged in a ribbon structure to interact to each other. The relationship of the arrangement of the 2-(2-thienyl)-5-[5-(tricyanoethenyl)-2-thienyl]pyrrole moieties with the metallic color of the crystals is discussed.
Interactions of Tetrakis(4-carboxyphenyl)porphyrin with Cyclodextrins in Aqueous Solutions Containing 1,1′-Diheptyl-4,4′-bipyridinium Dibromide
Authors: Hamai Sanyo
Published: November 2002

In pH 10.1 buffers, the interactions of tetrakis(4-carboxyphenyl)porphyrin (TCPP) with γ-cyclodextrin (γ-CD), heptakis(2,3,6-tri-O-methyl)-β-CD (TM-β-CD), and 1,1′-diheptyl-4,4′-bipyridinium dibromide (HB) have been examined by studying absorption, fluorescence, and induced circular dichroism spectra of TCPP. TCPP has been found to form inclusion complexes with γ-CD and TM-β-CD. The stoichiometries of the γ-CD–TCPP and TM-β-CD–TCPP inclusion complexes are 1 : 1 and 2 : 1, respectively. Because the equilibrium constant for the formation of the 2 : 1 TM-β-CD–TCPP inclusion complex is exceedingly large (4.34 × 1018 mol−2 dm6), the TM-β-CD–TCPP inclusion complex is quantitatively formed in TCPP solutions containing two equivalents of TM-β-CD. TCPP also forms an organic cation–organic anion complex with HB. In the presence of γ-CD, the TCPP–HB complex forms a 1 : 1 : 1 γ-CD–TCPP–HB inclusion complex, although TM-β-CD causes the dissociation of the TCPP–HB complex into its components. The equilibrium constant for the formation of the γ-CD–TCPP–HB inclusion complex from the TCPP–HB complex and γ-CD has been evaluated to be 905 mol−1 dm3.
Magnetic Field Effects on Anodic Oxidation of Potassium Iodide
Authors: Uechi Ichiro , Fujiwara Masao , Fujiwara Yoshihisa , Yamamoto Yohsuke , Tanimoto Yoshifumi
Published: November 2002

External magnetic fields (≤ 6 kG) significantly increase yields of I3− and H2 as well as oxidation currents in anodic oxidation of potassium iodide. The Lorentz force on ions in the solution induces convection of solution, resulting in acceleration of the entire reaction rate. This is further confirmed from the observation that reddish-brown streams of I3− in the solution, moving downward at zero field, undergo turbulent motion in magnetic fields.
Crystal Chemistry of Photodimers of 2-Benzyl-5-benzylidenecyclopentanone
Authors: Honda Kazumasa
Published: November 2002

The crystal structure of the photodimer of 2-benzyl-5-benzylidenecyclopentanone was determined using a recrystallized crystal. It was identical to that of an as-photoirradiated dimer crystal obtained by a single-crystal-to-single-crystal photoreaction of the monomer. This suggests that the starting material already possesses the most favored crystal phase for the products.
Recent Decline of Atmospheric Concentration and Emission of Methane in Nagoya Metropolitan Area
Authors: Ito Akinori , Yamada Shishin , Higuchi Takuya , Ishikawa Yuzo , Nagata Yoko , Chiba Koichi , Haraguchi Hiroki
Published: November 2002

Anthropogenic emissions of methane (CH4) from major sources such as landfills, automobiles, and rice paddy fields in the Nagoya metropolitan area were estimated using several emission process parameters such as emission factors and activity data for the decade from 1988 to 1997. The sum of CH4 amounts emitted from these three major sources was calculated to be 4.93 Gg of CH4 in 1988 and 5.19 Gg of CH4 in 1997. Methane emissions from the 12 landfill sites located around the Nagoya metropolitan area gradually increased until 1996 and then decreased in 1997, while those from automobiles and rice paddy fields continuously declined for the same decade. The total amount of CH4 emitted from the 12 landfills was much larger than those from other two sources. In 1993, for example, the amount was estimated as 3.26 Gg of CH4, 58% of which was generated from the largest landfill site. The excess CH4 concentration in the urban atmosphere, which was estimated from the difference between the CH4 concentration at the urban site and the background CH4 concentration at the Mauna Loa observatory, Hawaii, USA, showed the long-term trends similar to the CH4 emission from the largest landfill site. As a result, we conclude that the CH4 emission from the largest landfill dominantly impacted on the excess CH4 concentration due to the major sources in the Nagoya metropolitan area.
Conformation of 18-Membered Tetraimino Macrocyclic Complex; Structure of Two Metal Complexes and Molecular Mechanics Study
Authors: Tsubomura Taro , Ito Mitsuru , Fujita Tomochika
Published: November 2002

The conformations of metal complexes of 18-membered tetraimino macrocycles have been studied. A correlation between the bond length of the metal–nitrogen bond and the conformation of the macrocycle has been found in the published X-ray data. Molecular mechanics (MM) calculations based on the Points-On-a-Sphere (POS) method reproduce the correlation. The effect of the MM force constants on the conformation of the ligand has been extensively studied. The MM study clarified that the conformation of the macrocycle is principally determined by the length of the coordination bond and that the methyl groups substituted at the imine carbon plays an important role in the conformation of the macrocycles. Two X-ray crystal structure analyses of macrocycle LH complexes, [Ba(LH)(ClO4)2Ba(LH) (H2O)(ClO4)-(μ-ClO4)] and [Sr(LH)(ClO4)2], were included in the study to complement the structural data.
Intercalation of a Cationic Surfactant in the Interlayer Space of Smectites
Authors: Sakai Yasuzo , Kato Norihiro , Arai Misako , Takahashi Fujio , Nishida Yuichi
Published: November 2002

The properties of cationic surfactant-clay mixtures were examined by measurements of the electric conductivity, absorption spectra, and X-ray diffraction patterns. The orientation of N-[[4-(aminoiminomethyl)amino]butyl]dodecanamide (DAG) as a intercalated cationic surfactant and the thickness of the interlayer space of clay using Na-saponite (Sumecton SA) were investigated. DAG molecules were intercalated in a 1 nm gap in the interlayer space of clay. It is speculated that alkyl groups of the surfactant molecules are placed not parallel, but inclined slightly vertical to the internal surface of Na-saponite.
Transition Moments of Visible Region Absorption Bands of trans(Cl)-Triammineaquadichlorocobalt(III) Chloride
Authors: Mitsutsuka Yoshihiro , Nawa Nobuhiko , Yoshizawa Shuji , Yajima Hirofumi , Iriyama Keiji , Hidaka Hisao , Tsuboi Masamichi
Published: November 2002

From single crystals of trans(Cl)-[CoCl2(NH3)3(H2O)]Cl, thin sections with different orientations and different thicknesses were prepared, and their polarized absorption spectra were examined in the 350–850 nm region using a microspectrophotometer. Two absorption peaks, caused by the (x2−y2 ← xy)-type transitions of the d-electrons of Co, were found: a 15750 cm−1 peak was assigned to overlapping A2 ← A1 and B2 ← A1 type transitions of the complex ion with C2v symmetry; a 19210 cm−1 peak was assigned to a B1 ← A1 type transition. The molar extinction coefficients (ε) were determined at each of these peaks: ε(||c) = 104 and ε (⊥c) = 16 l cm−1 mol−1 at 15750 cm−1, and ε(||c) = 5 and ε(⊥c) = 54 l cm−1 mol−1 at 19210 cm−1. These ε values were explained by taking distortions of the d-electron orbitals into consideration, that are partly caused by the oxygen atom coordination and partly by some vibronic couplings between the d-electron orbitals and cobalt-ligand stretching vibrations.
Formation of Two Chromium(III) Dithiocarbamates from Cr(VI) in Solvent Extraction System and Origin of Oxygen Atom in Bis(1-pyrrolidinecarbodithioato)[1-pyrrolidinecarbothio(thioperoxoato)]chromium(III)
Authors: Honma Yoshiro
Published: November 2002

In order to explore the cause of a distinctive extraction behavior of Cr(VI) in the dithiocarbamate formation-solvent extraction systems, extracted chromium compounds were investigated and relationships between the formation of the compounds and the extraction behavior were studied. Chromatographic separation and spectroscopic analyses showed that two kinds of chromium(III) dithiocarbamates (i.e. tris(1-pyrrolidinecarbodithioato)chromium(III) and bis(1-pyrrolidinecarbodithioato)[1-pyrrolidinecarbothio(thioperoxoato)]chromium(III)) were formed and extracted in an ammonium 1-pyrrolidinecarbodithioate (APCD)/diisobutyl ketone (DIBK) solvent extraction system. The two products comprised most of the extracted chromium. Concentrations of the two dithiocarbamates in extracts were determined using double wavelengths analysis. The dependence of concentration ratio of the two complexes on pH was also investigated. The results of the investigation clarified that a major extract obtained under high pH condition was the thioperoxo complex and that the percentage of the tris complex increased with decreasing pH. Furthermore, it was clarified that the unusual extraction behavior of chromate was distinguished by the formation of thioperoxo complex. In order to elucidate the formation mechanism of the thioperoxo complex, the origin of an oxygen atom in the molecule of the thioperoxo complex was determined with an isotope labeling technique. The labeling experiments clarified that the source of the oxygen atom of the complex molecule was chromate ion and that the oxygen atom was fixed to chromium atom prior to the rate determination step of the formation of the thioperoxo complex.
New Zinc(II) Complexes with Tetradentate Amino Acid Derivatives: Structure Characterization, Solution Chemistry, and in vitro Insulinomimetic Activity
Authors: Yoshikawa Yutaka , Kawabe Kenji , Tadokoro Makoto , Suzuki Yuka , Yanagihara Naohisa , Nakayama Akihiro , Sakurai Hiromu , Kojima Yoshitane
Published: November 2002

Twelve new amino acid derivatives/Zn(II) complexes were prepared by the reactions of ZnSO4 and nine tetradentate ligands, Gly, Ala, Val, Leu, Ser and His derivatives and three pentadentate ligands, Asp and His derivatives. The X-ray structure analysis of [Zn3(N-pyridylmethyl-His)3(H2O)2](ClO4)3·2H2O revealed the formation of a trinuclear complex, in which three tetradentate ligands and two water molecules coordinate to three Zn(II), but the complex in an aqueous solution is present as a monomeric complex ion. Several Zn(II) complexes were found to have in vitro insulinomimetic activity which was estimated by the inhibition of free fatty acid release in isolated rat adipocytes treated with epinephrine. It was revealed that the insulinomimetic activities of Zn(II) complexes with the stability constants (log β) less than 11 were higher than that of VOSO4 and were comparable to that of ZnSO4 as positive controls except in the cases of two complexes with Gly derivatives, Zn(N,N-dipyridylmethyl-Gly)+ and Zn(N,N′-trimethylene-bis-Gly).
Preparation, Crystal Structures, Electrochemical and Spectroscopic Properties of Bis(2,2′-bipyridine)ruthenium(II) Complexes Containing 8-(Diphenylphosphino)quinoline or 2-(Diphenylphosphino)pyridine
Authors: Suzuki Takayoshi , Kuchiyama Takashi , Kishi Shinobu , Kaizaki Sumio , Kato Masako
Published: November 2002

Mixed-ligand bis(2,2′-bipyridine)ruthenium(II) complexes containing a hybrid donor-type P–N ligand of 8-(diphenylphosphino)quinoline (Ph2Pqn) or 2-(diphenylphosphino)pyridine (Ph2Ppy), [Ru(bpy)2(Ph2Pqn or Ph2Ppy)](PF6)2 (1 or 2; bpy = 2,2′-bipyridine), have been prepared. The X-ray crystal structure analyses of 1 and 2 revealed that Ph2Pqn and Ph2Ppy act as a bidentate ligand to form a five- and four-membered chelate ring, respectively. The four-membered chelate ring formed by Ph2Ppy has a very small bite angle (P(1)–Ru–N(1): 68.4(1)°), but the RuII(bpy)2 moiety in 2 has a typically strain-free structure. On the other hand, in the Ph2Pqn complex 1, one of the bpy planes is skewed remarkably from the Ru coordination plane due to an intramolecular steric interaction with a phenyl ring of Ph2Pqn. The redox potentials and the 1MLCT transition energies of the Ph2Pqn and Ph2Ppy complexes (1 and 2) were not so different from the averaged values of those of the corresponding 1,2-bis(diphenylphosphino)benzene (dppb) and 1,10-phenanthroline (phen) complexes, [Ru(bpy)2(dppb or phen)](PF6)2 (3 or 4). These facts indicate that the electronic asymmetry inherently present in Ph2Pqn and Ph2Ppy does not affect remarkably the ground state properties of the complexes. However, unlike complexes 2–4, the Ph2Pqn complex 1 in EtOH/MeOH (4 : 1) glass at 77 K exhibited a novel dual emission, giving a biexponential emission decay. The shorter-lived (τ = 10.8 µs) emission is attributable to the bpy-based 3MLCT emission, similar to the other RuII-polypyridine complexes, while the longer-lived (τ = 62.1 µs) emission can probably be assigned as arising from the quinoline-based 3(π–π*) excited state.
Valence States and Structure of Mixed-Valence Dinuclear Iron(II,III) Complexes [Fe2(2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-methylphenol)(L)2](BF4)2
Authors: Maeda Yonezo , Ishida Akiko , Ohba Masaaki , Sugihara Shinji , Hayami Shinya
Published: November 2002

Mixed-valence dinuclear iron(II,III) complexes, [FeIIFeIII(bpmp)(L)2](BF4)2, have been prepared, and the structures, electrochemical properties and rates of intramolecular electron transfer of the complexes have been examined, where Hbpmp represents 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-methylphenol and L is 2-methoxybenzoate (omb), 3-methoxybenzoate (mmb), 4-methoxybenzoate (pmb), 3,5-dimethoxybenzoate (dmb), 3,4,5-trimethoxybenzoate (tmb) or 4-biphenylcarboxylate (bpc). It turns out from the Mössbauer spectra that the valence states of iron atoms of [FeIIFeIII(bpmp)(omb)2](BF4)2, [FeIIFeIII(bpmp)(pmb)2](BF4)2, [FeIIFeIII(bpmp)(tmb)2](BF4)2 and [FeIIFeIII(bpmp)(bpc)2](ClO4)2 are localized at 78 K and delocalized at 293 K. The temperature dependence of the spectra is interpreted by assuming intramolecular electron transfer between two energetically equivalent vibronic states FeAIIFeBIII and FeAIIIFeBII. The Mössbauer spectra of [FeIIFeIII(bpmp)(dmb)2](BF4)2 show the superposition of the relaxation spectrum between iron(II) and iron(III), and of the spectrum of the average valence states at 293 K; the average valence states are partly observed even at 78 K. The valence states of [FeIIFeIII(bpmp)(mmb)2](BF4)2 are localized over the temperature range from 78 K to 293 K. The single-crystal X-ray structure of [FeIIFeIII(bpmp)(bpc)2](ClO4)2 was determined at 293 K. The complex crystallizes in the orthorhombic space group Fdd2, which has a unit cell of a = 27.056(1) Å, b = 42.652(0) Å, c = 12.151(0) Å and Z = 8. A refinement was performed with 2340 unique reflections [I > 3σ(I)] to give R = 0.085, Rw = 0.099. The two iron atoms are located symmetrically to a C2 axis, which presents in the molecule, and are crystallographically equivalent. The mean Fe–O length is intermediate between the FeII–O and FeIII–O values, indicating that both iron atoms are in an averaged valence state.
Synthesis, Characterization and Spin-Crossover Behaviors of [Co(hydroxycarboxylato)(triphos)] Complexes
Authors: Enamullah Mohammed , Hasegawa Miki , Fukuda Yutaka , Linert Wolfgang , Hoshi Toshihiko
Published: November 2002

2,2,2-Tris(diphenylphosphinomethyl)ethane (triphos) coordinates to Co(BF4)2·6H2O to synthesis the red-violet cationic complex of [Co(triphos)(solv)2]2+ (solv: solvent) in THF/EtOH at room temperature. Addition of 2-hydroxy-2-d-carboxylic acids (L) into the cationic solution as co-ligands yields the red-brown complexes of [Co(l-2-hydroxy-2-methylacetato)(triphos)] (I), (Co(d-2-hydroxy-2-phenylacetato)(triphos)] (II), (Co(l-2-hydroxy-2-phenylacetato)(triphos)] (III) and [Co(d-2-hydroxy-2-phenyl-2-methylacetato)(triphos)] (IV). The complexes are characterized by elemental analysis, IR-, UV-vis.-, NMR- and Mass-spectroscopy. All complexes are paramagnetic. Variable temperature studies on magnetic susceptibilities (χM) measurements show the spin-crossover behaviors of the complexes with ΔHsc = −5.3 to −6.8 kJ mol−1 and ΔSsc = −31 to −36 J mol−1 K−1 in methanol.
Metal-Azide-Pyrimidine Complexes M(N3)2(pm) with a Three-Dimensional Network Showing Weak Ferromagnetism for M = Mn and Fe and Antiferromagnetism for M = Co and Ni
Authors: Doi Yoshitaka , Ishida Takayuki , Nogami Takashi
Published: November 2002

Antiferromagnetic phase transitions of M(N3)2(pm) were observed at 51, 39, 41, and 46 K for M = Mn, Fe, Co, and Ni, respectively; here pm denotes pyrimidine. Single-crystal X-ray crystallographic analysis for M = Mn, Fe, and Co and powder X-ray diffraction measurements for M = Ni revealed that they were isomorphous. The N3 and pm moieties contribute μ-1,3-bridged two-dimensional and μ-1,3-bridged one-dimensional structures, respectively, thus forming a three-dimensional framework. Antiferromagnetic couplings through the bridging ligands are consistent with superexchange mechanisms based on the coordination geometry determined. Small spin canting was observed below the transition temperature for M = Mn and Fe. The cant angles are estimated to be 0.06 and 0.13°, respectively, from the spontaneous magnetization at 10 K.
Crystal Structures and Magnetic Properties of Copper(II) Hexafluoroacetylacetonate Complexes with hnn and hin and Manganese(II) Hexafluoroacetylacetonate Complex with hin (hnn = 4,4,5,5-Tetramethylimidazolin-1-oxyl 3-Oxide; hin = 4,4,5,5-Tetramethylimidazolin-1-oxyl)
Authors: Ise Tomoaki , Ishida Takayuki , Nogami Takashi
Published: November 2002

We report here the structures and magnetic properties of hnn and hin complexes with copper(II) and manganese(II) hexafluoroacetylacetonates, [{Cu(hfac)2(H2O)}2(μ-hnn)] (1), [Cu(hfac)2(hin)2] (2), and [Mn(hfac)2(hin)2] (3). X-ray crystallographic analysis of 1 revealed that 1 was a dinuclear complex containing an hnn bridge. Magnetic measurements of 1 indicate the presence of intramolecular ferromagnetic coupling between copper and radical spins. The data were analyzed as a metal-radical-metal three-spin system, giving 2J/k = +16.2 K (H = −2J(S1S2 + S2S3)). The ferromagnetic interaction can be explained in terms of the axial coordination of the hnn nitrogen to Cu(II). Complexes 2 and 3 were revealed to be isomorphous mononuclear complexes possessing two hin ligands. Although the molecules have a radical-metal-radical system, the magnetic data of 3 could not be analysed only with intramolecular interactions. Strong intermolecular antiferromagnetic interactions (2|J|/k >> 300 K) were suggested among the hin ligands because the interatomic O···N distances (2.41–2.51 Å) were shorter than the sum of the van der Waals radii for 2 and 3. These strong interactions are successfully introduced to metal-radical hybrid systems owing to the choice of small ligands, although the complexes do not possess polymeric networks.
Syntheses of a 6-(2-Pyrrolyl)-2,2′-bipyridine Derivative and Its Ruthenium Complex
Authors: Nagata Toshi , Tanaka Koji
Published: November 2002

Syntheses of a new planar terdentate ligand, 6-(3,5-diphenyl-2-pyrrolyl)-2,2′-bipyridine (L1H) and its ruthenium(II) complex ([Ru(L1)2]) are reported. The X-ray structure of [Ru(L1)2] showed the distorted octahedral Ru(II) center similar to the structures of terpyridine complexes. The cyclic voltammograms revealed that [Ru(L1)2] was more easily oxidized than [Ru(terpy)2]2+ by 1.10 V.
Determination of the Rates of Formation and Hydrolysis of the Schiff Bases Formed by Pyridoxal 5′-Phosphate with l-Tryptophan and Its Methyl and n-Butyl Esters
Authors: Gorostidi Gerardo R Echevarría , Santos José G , Basagoitia Andrea , Blanco Francisco García
Published: November 2002

The apparent rate constants of the formation (k1) and hydrolysis (k2) of the Schiff bases formed by pyridoxal 5′-phosphate with l-tryptophan and their methyl and n-butyl esters at a variable pH, 25 °C, and an ionic strength of 0.1 M were determined, along with the equilibrium constant (KpH). The individual rate constants of formation and hydrolysis of the Schiff bases of systems corresponding to different chemical species present in the medium as a function of its acidity were also determined, as were the pK values for the Schiff bases. The influence of the α-carboxyl group on the formation and hydrolysis constants of the Schiff bases, and also on their pK values, is demonstrated.
Epimerization in Intramolecular Carbanilide Cyclization to Hydantoins: A Computational Study
Authors: Gong Young-Dae , Kim Soo-Kyung , Yoo Sung-eun , Kurth Mark J
Published: November 2002

An efficient and diastereoselective route for the synthesis of 2,5,6,7-tetrasubstituted-1H-pyrrolo[1,2-c]imidazoles has been developed using intramolecular azomethine ylide cycloaddition and carbanilide cyclization. Ab initio calculations at the 6-31G (d,p) basis set reveal that the thermal stability of diastereomers determine the epimerization during the intramolecular carbanilide cyclization (→ hydantoin). These stereochemical results are consistent with an endo-like cycloaddition of a trans,anti-azomethine ylide followed by base-mediated C7a-H epimerization (C7a-Hβ → C7a-Hα) to deliver the thermodynamically preferred trans,anti,trans-(Ha-Hb, Hb-Hc, Hc-Hd)-pyrrolidine stereochemistry (3) which is ca. 20.1 kJ/mol more stable than the trans,anti,cis-pyrrolidine stereochemistry. In the case of 2-hydroxy-1-naphthaldehyde, naphthalene ring steric effects result in a different stereochemical arrangement about each pyrrolidine ring.
A Convenient Synthesis of 2H-1,4-Benzoxazines, 3H-Indol-3-ones, and 2,3-Dihydrobenzoxazoles
Authors: Abdou Wafaa Mahmoud , Salem Mounir Abdou Ibrahim , Sediek Ashraf Ahmed
Published: November 2002

3,5-Di-tert-butyl-1,2-benzoquinone 1-oxime (1b) reacted with ester ylides 2a,b to give the corresponding 2H-1,4-benzoxazin-2-ones 9a,b along with the 3H-indol-3-one 11, whereas with keto ylides 12a,b, 2,3-dihydrobenzoxazoles 13a,b were isolated. Conversely, the reaction of 1b with moderated phosphonium salt 15 proceeded under phase-transfer catalysis conditions to afford the 2H-1,4-benzoxazine derivative 19, instead of the expected Wittig reaction product.
Photochemical E(trans)–Z(cis) Isomerization in 9-Anthraceneacrylic Esters
Authors: Reddy Majjigapu Janaki Ram , Srinivas Uppalanchi , Srinivas Kolupula , Reddy Vummadi Venkat , Rao Vaidya Jayathirtha
Published: November 2002

Several (1–6) 9-anthraceneacrylic esters were synthesized in order to study photochemical E(trans)–Z(cis) isomerization. All of the compounds 1–6 underwent selective E-to-Z isomerization upon direct excitation (> 400 nm) in organic solvents, leading to the formation of a thermodynamically less stable Z isomer over 96%. Triplet sensitized isomerization selectively produces the Z-to-E isomer in over 98%. The higher quantum yield of isomerization observed in the triplet-sensitized Z-to-E isomerization process informs us that a “quantum chain” process is in operation. Fluorescence data generated on all compounds indicate that the E-to-Z isomerization process involves a charge-transfer or polar singlet excited state.
Palladium-Catalyzed Carbonylative Coupling of Tributyl(1-fluorovinyl)stannane with Aryl Halides and Aryl Triflates
Authors: Hanamoto Takeshi , Handa Kumiko , Mido Tomonori
Published: November 2002

We have found that tributyl(1-fluorovinyl)stannane (2) could be readily prepared from the reaction of (1-fluorovinyl)methyldiphenylsilane1 (1) and bis(tributyltin) oxide in the presence of a catalytic amount of CsF in DMF in good yields. The palladium-catalyzed carbonylative cross-coupling reaction of 2 with aryl iodides bearing various functional groups smoothly proceeded giving the corresponding aryl 1-fluorovinyl ketones in good yields under an atmospheric pressure of carbon monoxide. A similar carbonylative cross-coupling reaction of 2 with aryl triflates was also accomplished in the presence of tetrabutylammonium iodide (Bu4NI) as an additive.
Verification of Conformation Change in Ca2+-Bound S-100 Proteins Caused by Mg2+-Binding
Authors: Matsuda Sadayuki
Published: November 2002

The conformation changes of S-100a.a′ and S-100b caused by Mg2+-binding were determined by several methods. The fluorescence intensity of the Ca2+-bound S-100a.a′ was enhanced by the Mg2+-binding. The conformation changes in Ca2+/S-100a.a′ and Ca2+/S-100b caused by Mg2+-binding were also detected using a fluorescence environmental probe, 2-p-toluidinonaphthalene-6-sulfonate (TNS). The reactivities of the cysteine (Cys) residues in S-100a.a′ and S-100b to a thiol-specific reagent, 2,2′-dinitro-5,5′-dithiodibenzoic acid (DTNB), were increased by the Mg2+-binding, regardless of the Ca2+-binding.
A Novel Aspect of the Reaction of Ivermectin Aglycon Producing 13-Substituted-14Z Derivative
Authors: Sugiyama Yoko , Takahashi Hiroaki , Saito Akio
Published: November 2002

During research to synthesize 13-deoxy-13β-substituted ivermectin aglycons, unexpected unique products, 13β-substituted-14Z ivermectin aglycons, were obtained. We will report the results of that series of studies and a possible reaction mechanism.
A New Synthetic Method for the Preparation of α,β-Didehydroamino Acid Derivatives by Means of a Wittig-Type Reaction. Syntheses of (2S, 4S)- and (2R, 4R)-4-Hydroxyprolines
Authors: Kimura Rumi , Nagano Tanemasa , Kinoshita Hideki
Published: November 2002

Ethyl N-Boc- and N-Z-α-tosylglycinates were reacted with a variety of aldehydes in the presence of tributylphosphine and a base to afford the corresponding α,β-didehydroamino acid derivatives with high (Z)-selectivity in good yields. Moreover, ethyl (4S)- and (4R)-2-(N-Boc-amino)-4,5-isopropylidenedioxy-2-pentenoates prepared by the present method were converted to (2S, 4S)- and (2R, 4R)-4-hydroxyprolines, respectively.
Radiolytic Degradation of Chlorinated Hydrocarbons in Water
Authors: Wu Xing-Zheng , Yamamoto Takeshi , Hatashita Masanori
Published: November 2002

Radiolytic degradation of chlorinated hydrocarbons (chloroform, trichloroethylene, and tetrachloroethylene) in water was carried out. Water solutions of the chlorinated hydrocarbons with different concentrations were irradiated with γ rays. Concentrations of methane, ethane, CO, CO2, H2, and O2 after the irradiation were determined by gas chromatography. Concentration of chloride ion in the irradiated sample was determined by ion chromatography. Experimental results show that radiolytic degradation of the chlorinated hydrocarbon increased with the radiation dose. Methane, ethane, CO2, H2, and Cl− concentrations increased with the radiation dose and the sample concentration. On the other hand, O2 concentration decreased with the radiation dose and the sample concentration. When sample concentration was high, dissolved oxygen might be not enough for converting most of the C atoms in the sample into CO2. This resulted in a low decomposition ratio. Addition of H2O2 as an oxygen resource could increase the decomposition ratio greatly. Furthermore, gas chromatography-mass spectroscopy was applied to identify some intermediates of the radiolytic dehalogenation. Radiolytic degradation mechanisms are also discussed.