bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectroelectrochemistry of Porphyrin Containing Mono- and Hetero-Bimetallic Systems: Porphyrin-Ru(bpy)3 Conjugates
Authors: Lintuluoto Juha M , Borovkov Victor V , Hembury Guy A , Inoue Yoshihisa 
Published: February 2003

Abstract
The redox behavior of porphyrin-Ru(bpy)3 conjugates is studied by means of spectroelectrochemistry. The redox potentials for the porphyrin freebase, zinc and manganese derivatives are measured and compared to the corresponding monomeric reference porphyrins. Among the porphyrin-Ru(bpy)3 conjugates, the manganese derivative behaved like its monomeric reference compound, the zinc derivative showed moderate differences, and the freebase derivative exhibited the largest differences. These results are understood to originate from the extended orbital overlap of the redox reaction centers. In the case of the freebase derivative, the bpy ligand of the Ru(bpy)3 moiety is spacially very close to one of the porphyrin moiety’s π-system pyrroles, which is acting as a redox reaction center. For the zinc derivative this effect is more moderate; and because the redox reactions in the manganese derivative occur at the manganese central metal, which is too far from the bpy group, the effect is minimal. From the viewpoint of the Ru(bpy)3 moiety, the redox reactions of the Ru metal are not affected by the presence of the porphyrins due to the absence of Ru-porphyrin orbital overlap.
Modified Hydroborate Agent: (2,2′-Bipyridyl)(tetrahydroborato)zinc Complex, [Zn(BH4)2(bpy)], as a New, Stable, Efficient Ligand-Metal Hydroborate and Chemoselective Reducing Agent
Authors: Zeynizadeh Behzad 
Published: February 2003

Abstract
(2,2′-Bipyridyl)(tetrahydroborato)zinc complex, [Zn(BH4)2(bpy)], is a new white stable compound which has been used for efficient reduction of variety of carbonyl compounds such as aldehydes, ketones, acyloins, α-diketones and α,β-unsaturated carbonyl compounds (1,2-reduction) to their corresponding alcohols in acetonitrile at room temperature. Excellent chemoselectivity was also observed for the reduction of aldehydes over ketones with this reducing agent.
Syntheses and Properties of Sila-Functional Oligosiloxanes—Linear and Cyclic Tetrasiloxanes with Methyl and Vinyl Groups—
Authors: Gunji Takahiro , Watanabe Miho , Abe Koji , Abe Yoshimoto 
Published: February 2003

Abstract
The syntheses of the titled oligosiloxanes by controlled hydrolysis of the corresponding isocyanatosilanes under vapor phase or in THF (or THF/ether) were investigated. The vapor phase hydrolysis of RSi(NCO)3 (R = Me, Vinyl) with a water–1,4-dioxane vapor gave the disiloxanes [R(OCN)2Si]2O in yields of 85% (R = Me) and 90% (R = Vinyl). Further vapor phase hydrolysis of the disiloxanes provided the linear tetrasiloxanes NCO[SiR(NCO)O]3SiR(NCO)2 in yields of 71% (R = Me) and 69% (R = Vinyl). The cyclotetrasiloxanes [R(OCN)SiO]4 were synthesized in yields of 12% (R = Me) and 33% (R = Vinyl) or 24% (R = Me) and 58% (R = Vinyl) by hydrolysis of the disiloxanes or of the linear tetrasiloxanes in THF, respectively. On the other hand, the linear tetrasiloxanes OCN[SiR(OPri)O]3SiR(OPri)(NCO) were obtained in yields of 50% (R = Me) and 56% (R = Vinyl) by hydrolysis of [R(OCN)(PriO)Si]2O prepared from RSi(OPri)(NCO)2 under mild conditions in THF/ether, while the cyclic tetrasiloxanes [R(PriO)SiO]4 were afforded in the yield of 61–62% by hydrolysis of the disiloxanes under more severe conditions in THF.
Successive Carbon–Carbon Bond Formation by Sequential Generation of Radical and Anionic Species with Manganese and Catalytic Amounts of PbCl2 and Me3SiCl
Authors: Takai Kazuhiko , Ueda Takashi , Ikeda Norihiko , Ishiyama Takaya , Matsushita Hiroshi 
Published: February 2003

Abstract
Three-component coupling reactions of iodoalkanes, α,β-unsaturated nitriles (or esters), and carbonyl compounds are achieved in good to excellent yields with a moderate reducing system derived from manganese metal and a catalytic amount of PbCl2 and Me3SiCl. Although the role of PbCl2 is unclear, addition of a catalytic amount of the salt is essential for reducing the iodoalkane. The reaction proceeds with primary, secondary, and tertiary iodoalkanes. Both acrylonitrile and acrylic esters can be employed as activated olefins, while the reaction with an alkyl vinyl ketone gives a complex mixture. Ketones and aldehydes can be used as the third component and the diastereoselectivity of the anionic addition is approximately 1 : 1–2 : 1 ratio. By using the heterogenerative process, i.e., successive 1,4-addition by radical and anionic internal addition, cyclopropanation of electron-deficient olefins is achieved with chloroiodomethane, manganese, PbCl2, Me3SiCl, and DMAP.
Synthesis of Novel Thermally Irreversible Photochromic 1-Aryl-1,3-butadiene Derivatives
Authors: Shrestha Sujen Man , Nagashima Hitoshi , Yokoyama Yayoi , Yokoyama Yasushi 
Published: February 2003

Abstract
A new thermally irreversible photochromic compound, 3,3,4,4,5,5-hexafluoro-1-(1-isopropylidene-1-phenylmethyl)-2-(2,4,5-trimethyl-3-thienyl)cyclopentene 3O, was synthesized and its photochromic properties were examined. It showed thermally irreversible photochromism. While 3O is colorless, it turned yellow (λmax 445 nm) upon the irradiation of 313-nm light, caused by the generation of 3C as the result of photochemical 6π-electrocyclization. It returned to the initial colorless state by 405-nm light irradiation. The coloration and decoloration quantum yields with 313-nm light were 0.43 and 0.14, respectively, and the decoloration quantum yield with 405-nm light was 0.16. The colored form 3C in a PMMA film did not fade when stored at 80 °C for more than one month, and the fatigue resistivity in the PMMA film for iterative irradiation was excellent.
Enzymatic Oxidative Polymerization of p-t-Butylphenol and Characterization of the Product Polymer
Authors: Mita Naruyoshi , Maruichi Naoyuki , Tonami Hiroyuki , Nagahata Ritsuko , Tawaki Shin-ichiro , Uyama Hiroshi , Kobayashi Shiro 
Published: February 2003

Abstract
For structural control and analysis of an enzymatically synthesized polyphenol, peroxidase-catalyzed polymerization of p-t-butylphenol in a mixture of polar organic solvent and phosphate buffer has been examined in detail. The resulting products were subjected to preparative HPLC. Two dimers and one trimer were isolated and their structures were determined by 1H and 13C NMR. ESI-TOF mass analysis showed the formation of two kinds of dimer and of at least four kinds of trimer. These data clearly showed that the polymer was composed of a mixture of phenylene and oxyphenylene units. The ratio of phenylene and oxyphenylene units in the product could be controlled by changing the solvent composition. The phenylene unit linearly increased as a function of the water content in the mixed solvent.
Organic Photoconductors Using a Novel Charge-Transport Material, 2-[p-Di(p-tolyl)aminostyryl]-4-methylthiazole
Authors: Aratani Sukekazu , Suzuki Shigeo , Kawanishi Tsuneaki , Kakuta Atsushi 
Published: February 2003

Abstract
Organic photoconductors using 2-[p-di(p-tolyl)aminostyryl]-4-methylthiazole, which is a newly developed material with high hole mobility, as a charge-transport material and τ-type metal-free phthalocyanine as a charge-generation material, have been examined. The photoconductors showed an excellent photoresponse, but had a high residual potential. In order to ascertain the reason for this, the variation of the xerographic gain with the thickness of the charge-transport layer and the electric field was measured. The results suggested that a large energy barrier between 2-[p-di(p-tolyl)aminostyryl]-4-methylthiazole and τ-type metal-free phthalocyanine induced a large decrease in the xerographic gain at a low electric field, which caused a high residual potential.
Preparation and Properties of Kinetically Stabilized Phosphaethene Derivatives Carrying the Methylsulfanyl Group
Authors: Ito Shigekazu , Kimura Shigeo , Yoshifuji Masaaki 
Published: February 2003

Abstract
1-Methylsulfanyl-2-(2,4,6-tri-t-butylphenyl)-2-phosphaethenyllithiums, prepared from (Z)-2-bromo-2-methylsulfanyl-1-(2,4,6-tri-t-butylphenyl)-1-phosphaethene, displayed an E/Z isomerization upon warming to room temperature. The copper-mediated coupling reaction afforded (Z,Z)-2,3-bis(methylsulfanyl)-1,4-diphosphabuta-1,3-diene. The reaction of the phosphaethenyllithiums with dimethyl disulfide and iodomethane gave the corresponding bis(methylsulfanyl)phosphaethene and a methylated E-isomer, respectively. On the other hand, the latter methylated Z-isomer was alternatively prepared from (Z)-2-bromo-1-(2,4,6-tri-t-butylphenyl)-1-phosphapropene. Both methylated E- and Z-isomers were allowed to react with W(CO)5(thf) to give the corresponding pentacarbonyltungsten(0) complexes, either of which was deprotonated to give the 3-phospha-2-propenyllithium derivative leading to the formation of a homocoupled (Z,Z)-1,6-diphosphahexa-1,5-diene complex. Some key compounds were analyzed by X-ray crystallography, revealing the effect of the methylsulfanyl group on the structures. A straightforward preparation of 1-(2,4,6-tri-t-butylphenyl)-1-phosphaallene as well as its carbonyltungsten(0) complex is also described.
Convenient Methods for the Preparation of Unsymmetrical Double Aldols
Authors: Mukaiyama Teruaki , Pudhom Khanitha , Yamane Keiko , Arai Hidehiro 
Published: February 2003

Abstract
Double aldol reaction proceeded stereoselectively at one α-carbon of ketones to give α-(1-hydroxyalkyl)-β-hydroxyalkyl ketones (double aldols) in good to high yields by the following three methods: i) tin(II) trifluoromethanesulfonate-mediated aldol reaction of aldehydes with β-hydroxy ketones (mono-aldols) in the presence of tertiary amines, ii) samarium(II) iodide-mediated aldol reaction of aldehydes with alkyl or aryl oxiranyl ketones, iii) Sn(OTf)2-promoted aldol reaction of α-bromo ketones with aldehydes giving α-bromo-β-stannyloxy ketones which were then converted to titanium enolates on treatment with low-valent titanium. Double aldols were formed by subsequent reaction of the above titanium enolates with aldehydes in one-pot procedure. Further, small and medium-sized carbocyclic compounds whose ring skeletons were composed of double aldol structure were synthesized by SmI2-mediated intramolecular cyclization between oxiranyl ketone and aldehyde functions.
Effect of Photoirradiation on the Properties of Layered Titanate Thin Films from Transparent Aqueous Titanate Sols
Authors: Ohya Tomokazu , Nakayama Aki , Ban Takayuki , Ohya Yutaka , Takahashi Yasutaka 
Published: February 2003

Abstract
UV irradiation on films prepared by a spin-coating method using aqueous titanate sols was investigated. The transparent sols used in this study were prepared by a reaction of titanium tetraisopropoxide (TIP) with tetramethylammonium hydroxide (TMAOH) or alkylamines, and consisted of a layered compound. The refractive indices and hardening of the films increased with the irradiation time, indicating that photoirradiation accelerated densification of the films. It was found that these phenomena were caused by the photocatalytic decomposition of alkylammonium ions located between the titanate sheets to contract the interlayer distance. Interestingly, when the film prepared from the TIP–TMAOH sol containing 30 mol% of sucrose to Ti was irradiated through a patterning mask and subsequently heated in air at 500 °C, the irradiated part of the film selectively turned dark brown due to residual carbon. It was thought that sucrose molecules were confined within the host titanate layers densificated by UV irradiation and that the oxidation of the sucrose by oxygen in air was difficult under heating because the densificated titanates might suppress the diffusion of oxygen.
On the other hand, such coloring of the films by sucrose was not found for films prepared from an aqueous suspension of crystalline TiO2 (anatase), an aqueous solution of TIP–lactic acid (LA)–NH3, and alcoholic sols such as the TIP–diethanolamine (DEA) system.
Transport Characteristics of Neutralization Dialysis and Desalination of Tap Water
Authors: Igawa Manabu , Mikami Kentaro , Okochi Hiroshi 
Published: February 2003

Abstract
In neutralization dialysis, the salt solution is desalinated continuously. The cations in desalination compartment are exchanged with protons in the acid compartment across a cation-exchange membrane and the anions are exchanged with hydroxide ions in the base compartment across an anion-exchange membrane. A simple index (C/J), where C is the source phase concentration (mol cm−3) and J is the flux (mol cm−2 min−1), was proposed for the estimation of the desalination properties in neutralization dialysis. The index was based on the concepts of the ion-exchange reaction rate at the membrane interface and was related to the permeation constant in the source-phase boundary layer at the membrane interface, Pa (cm min−1), as C/J = 1/(k1·Cex) + 1/Pa, where k1 is the rate constant of ion-exchange reaction (mol−1 cm4 min−1) and Cex is the ion exchange capacity of the membrane (mol cm−3). The desalination efficiency increased with the decrease of the desalination compartment thickness and the decrease of the linear velocity, which can be estimated well by using the index. Tap water was desalinated by neutralization dialysis and pure water was obtained at the outlet of the desalination cell.
Circulating nucleosomes and response to chemotherapy: An in vitro, in vivo and clinical study on cervical cancer patients
Authors: Trejo‐Becerril Catalina , Pérez‐Cárdenas Enrique , Treviño‐Cuevas Homero , Taja‐Chayeb Lucía , García‐López Patricia , Segura‐Pacheco Blanca , Chávez‐Blanco Alma , Lizano‐Soberon Marcela , González‐Fierro Aurora , Mariscal Ignacio , Wegman‐Ostrosky Talia , Dueñas‐González Alfonso 
Published: March 2003

AbstractIt is known that cell‐free DNA circulates in plasma/serum of patients with cancer and that part of this DNA circulates as nucleosomes that can be quantified by ELISA. We analyzed the effect of tumor and chemotherapy upon the levels of nucleosomes in vitro, in vivo and in cervical cancer patients. The levels of nucleosomes pre‐ and post‐treatment were correlated with response in 11 patients receiving chemotherapy. Nucleosomes were determined in nude mice treated with or without cisplatin and carrying tumors generated with HeLa cells, and in the cell lysate and supernatant of HeLa cells exposed to cisplatin in culture. In addition, nucleosomes were determined at different time points in patients and in rats receiving chemotherapy. Nucleosomes were higher in patients that controls (1,760 vs. 601, p = 0.0001). After 24 hr of treatment with oxaliplatin and gemcitabine, the levels decreased in 6 patients of whom 5 had response. Nucleosome levels differed between mice xenografted and not xenografted (765 vs. 378, p = 0.001) and between xenografted treated with or without cisplatin (650 vs. 765, p = 0.010), but not in tumor‐free animals treated and untreated with cisplatin (378 vs. 379, p = 0.99). In vitro, nucleosomes reached at peak 8 hr in cell lysates to decrease thereafter, whereas in supernatant, levels continued to increase up to 24 hr. Serial determination of nucleosomes in patients showed a rise within 6–12 hr and then a reduction to below the basal at 24 hr. In rats, nucleosomes had no major changes in those receiving oxaliplatin or the triple combination of cisplatin, gemcitabine and paclitaxel as compared to untreated controls. An overdose of this triple combination produced a transient elevation of almost 1,000 AU over the basal. Our results demonstrate that most of circulating nucleosomes originate from the tumor and that chemotherapy produces an early rise most likely due to tumor apoptosis and that nucleosomes are rapidly cleared from circulation. On the contrary, chemotherapy within the therapeutic range of doses has no effect on nucleosome levels in healthy mice and rats. This data suggests that the determination of circulating nucleosomes pre‐ and post‐treatment could be a useful test to predict response to chemotherapy in cancer patients. © 2003 Wiley‐Liss, Inc.
Requirement of both mucins and proteoglycans in cell‐cell dissociation and invasiveness of colon carcinoma HT‐29 cells
Authors: Truant Stéphanie , Bruyneel Erik , Gouyer Valérie , De Wever Olivier , Pruvot François‐René , Mareel Mark , Huet Guillemette 
Published: March 2003

AbstractHuman colon carcinomas are characterized by an aberrant expression of mucins, which in some case leads to an abundant presence of mucus such as in mucinous and signet ring cell carcinomas. Cellular cloning of the human colon carcinoma cell line HT‐29 (HT‐29 STD), which is mainly composed of undifferentiated cells, yielded a highly mucin‐secreting variant (HT‐29 5M21). The latter cloned cells cultured on plastic display a polarized organization with an apical secretion of MUC5AC mucin (Lesuffleur et al., Int J Cancer 1998;76:383–92.). Our aim was to study these 2 cell‐types as for the invasive and adhesive properties with regard to the function of E‐cadherin. HT‐29 STD cells were noninvasive in collagen type I, whereas HT‐29 5M21 cells were invasive, and the latter behavior was connected to a loss of function of E‐cadherin. Likewise, HT‐29 5M21 cells were characterized by a cell‐cell adhesion independent of E‐cadherin, in contrast to the E‐cadherin dependent cell‐cell adhesion of HT‐29 STD cells. Immunofluorescence of HT‐29 5M21 cells cultured on collagen type I showed the disappearance of the polarized organization, with a redistribution of apical mucins to the entire cell surface. Treatment of HT‐29 5M21 cells by 1‐benzyl‐2‐acetamido‐2‐deoxy‐α‐D‐galactopyranoside (GalNAcα‐O‐bn) or by β‐D‐xyloside revealed that both mucins and proteoglycans were involved in the loss of E‐cadherin function. The use of specific antibodies allowed to show that MUC5AC, MUC1 and heparan sulfate proteoglycans cooperated in the formation of a biological inhibitory complex towards the function of E‐cadherin in this invasive HT‐29 clone. © 2003 Wiley‐Liss, Inc.
Strategies to avoid inappropriate therapies due to ventricular double detection in biventricular pacing implantable cardioverter/defibrillators
Authors: Kolb Christof , Zrenner Bernhard , Schreieck Jürgen , Schmitt Claus 
Published: February 2003

AbstractImplantation of biventricular pacing implantable cardioverter/defibrillators (ICD) is a new therapeutic approach for the treatment of chronic heart failure and the prevention of sudden cardiac death. Due to a common left and right ventricular sensing channel in first generation biventricular pacing ICD, ventricular double sensing and subsequent delivery of inappropriate therapies occurs in some patients. A case of inappropriate anti‐tachycardia pacing due to ventricular double detection is described. After programming short postventricular atrial refractory period, abandoning postventricular atrial refractory period extension in case of ventricular premature beats, increased upper rate limits and after careful selection of tachycardia detection criteria and anti‐tachycardia programming no further inappropriate therapy occurred.
NUTRICEUTICALS AND CARDIOVASCULAR HEALTH IN WOMEN
Authors: Fahs Pamela S. Stewart , Faucher Mary Ann 
Published: February 2003

ABSTRACTThis article examines the evidence on use of nutriceuticals for promotion of cardiovascular health in women. Studies elucidating mechanism of action, physiologic effects of antioxidant vitamins, carotenoids, flavonoids, and garlic are presented. Emerging evidence for the impact of homocysteine on cardiovascular risk factors and events and evidence for the impact of different types of fats on cardiovascular markers are reviewed. The effects of a heart‐healthy diet are supported in this review of research on nutriceuticals. Primary prevention of cardiovascular disease in women is clearly efficacious, and this article summarizes information to be shared with women about nutriceuticals and diet to better enable decisions they can adopt to promote cardiovascular health.
REDUCED FREQUENCY PRENATAL VISITS IN MIDWIFERY PRACTICE: ATTITUDES AND USE
Authors: Walker Deborah S. , Day Stephanie , Diroff Corinne , Lirette Heather , McCully Laura , Hescott Candace Mooney , Vest Victoria 
Published: February 2003

ABSTRACTRecent research supports the use of reduced frequency prenatal visit schedules (RFVS) for women of low obstetric risk. However, for the RFVS to be widely adopted for use in practice, health care providers must implement and support its use. The purpose of this study was to explore midwives'attitudes toward and use of reduced frequency prenatal care visit schedules for the care of low‐risk women. A descriptive, correlational study was conducted at the 1999 Annual Meeting of the American College of Nurse‐Midwives with completed surveys received from 234 midwives. Seventy‐two percent (n = 170) responded that they were familiar with the reduced frequency visit schedule. Of those, 71% agreed that they could give effective prenatal care by using reduced frequency scheduling, although few (17%) reported using it in practice. Significant differences were found between the midwives who were familiar versus those who were unfamiliar with the visit schedule in their perceptions for five central themes: 1) quality of care of the RFVS, 2) women's empowerment or self‐care with the RFVS, 3) ability to manage practice, 4) patient satisfaction, and 5) barriers to the use of RFVS. Providers'responses to the use of RFVS have been mixed. Successful integration of this schedule into prenatal care services may require more than knowledge of its safety for low‐risk women. Careful selection of women for whom the schedule is appropriate and a commitment from midwives to tailor prenatal care to the individual women's needs is indicated. Further research is also needed to evaluate the barriers that prevent midwives from using a reduced frequency visit schedule for the prenatal care of low‐risk clients.
ASSESSING THE QUALITY OF INFERTILITY RESOURCES ON THE WORLD WIDE WEB: TOOLS TO GUIDE CLIENTS THROUGH THE MAZE OF FACT AND FICTION
Authors: Okamura Kyoko , Bernstein Judith , Fidler Anne T. 
Published: February 2003

ABSTRACTThe Internet has become a major source of health information for women, but information placed on the World Wide Web does not routinely undergo a peer review process before dissemination. In this study, we present an analysis of 197 infertility‐related Web sites for quality and accountability, using JAMA's minimal core standards for responsible print. Only 2% of the web sites analyzed met all four recommended standards, and 50.8% failed to report any of the four. Commercial web sites were more likely to fail to meet minimum standards (71.2%) than those with educational (46.8%) or supportive (29.8%) elements. Web sites with educational and informational components were most common (70.6%), followed by commercial sites (52.8%) and sites that offered a forum for infertility support and activism (28.9%). Internet resources available to infertile patients are at best variable. The current state of infertility‐related materials on the World Wide Web offers unprecedented opportunities to improve services to a growing number of e‐health users. Because of variations in quality of site content, women's health clinicians must assume responsibility for a new role as information monitor. This study provides assessment tools clinicians can apply and share with clients.