bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of HMPA on the Structure and Reactivity of the Lithium Enolate of Cyclopentanone in THF: The Dimer is Responsible for Alkylation and Proton Exchange Reactions
Authors: Suzuki Masaaki , Koyama Hiroko , Noyori Ryoji
Published: February 2004

The structure and reactivity of the lithium enolate of cyclopentanone are strongly influenced by coexisting HMPA molecules. Detailed low-temperature 7Li, 31P, and 13C NMR studies of the 0.04–0.2 M THF solutions indicate that excess quantities of HMPA act primarily to form a bis-HMPA coordinated dimer. Tetrameric, trimeric, and monomeric enolates were not detected by HMPA titration. The convergency on the dimeric aggregate has been monitored by the successive displacement of THF with HMPA molecules. Even at a high concentration of HMPA, the formation of monomeric enolate was not observed. Kinetic experiments, combined with the structural information, showed that alkylation of the enolate by methyl iodide proceeds via the dimer with the assistance of HMPA. Proton exchange between the enolate and 2-methylcyclopentanone also occurs via the dimer, but without the participation of additional HMPA. These findings explain the role of HMPA in the selective monoalkylation of lithium enolate.
Effects of a High Magnetic Field on the Growth of 3-Dimensional Silver Dendrites
Authors: Katsuki Akio , Uechi Ichiro , Tanimoto Yoshifumi
Published: February 2004

A liquid/solid redox reaction between silver ions and copper metal was investigated under a vertical and inhomogeneous high magnetic field (maximum field strength: 15 T). The 3-dimensional silver dendrites produced via the reaction were drastically affected by the magnetic field. Black and round dendrites were obtained in the magnetic field, whereas metallic silver crystals were grown under the gray dendrites with no field. The yields of the silver dendrite and the copper ion increased significantly in presence of the magnetic field. The results are interpreted in terms of the magnetic convection of the solution, which is induced by the magnetic force on the paramagnetic copper ions generated in the reaction as well as by the Lorentz force on the ions.
Motif Analysis of Amino-Acid Sequences by a Quantification Method: Application to Phosphorylation Signals of Protein Kinase C and cAMP-Dependent Protein Kinase
Authors: Iida Yôichi
Published: February 2004

Prediction of protein function using amino-acid sequence motifs is based on the observation that the functionally important region is strongly conserved in short segments of amino-acid sequences. Although the consensus sequence has been used to describe such a functional signal, the actual sequence differs from it to a greater or lesser degree, and the consensus sequence only describes the signal qualitatively. In the present report, we study phosphorylation signals of protein kinase C (PKC) and cAMP-dependent protein kinase (PKA). PKC phosphorylates solely Ser or Thr residues. The consensus sequence is given by (R/K1–3,X2–0)-S/T-(X2–0,R/K1–3), where X denotes no particular amino acid. PKA also phosphorylates Ser or Thr, but its consensus sequence is described by R-R/K-X-S/T. We analyzed such signals by a quantification method, and estimated the strength of the signal quantitatively. This approach was applied to several proteins and peptide analogues, and the replacement effect of amino acids upon catalytic activities of phosphorylation was explained in terms of the strength of the signal (sample score of peptide sequence).
[{RhCl(CO)2}2]-Derived MCM-41-Tethered Rhodium Complex Catalysts via Phosphine, Amine and Thiol Ligands for Cyclohexene Hydroformylation
Authors: Huang Lin , Kawi Sibudjing
Published: February 2004

Functionalized silicate MCM-41-tethered rhodium complexes derived from [{RhCl(CO)2}2] have been studied by infrared spectroscopy (IR), X-ray diffraction (XRD) and N2 adsorption–desorption. [{RhCl(CO)2}2] reacts with aminated MCM-41 to result in a splitting of the chloride bridge. The same result is presumed with phosphinated MCM-41. Thiolated MCM-41 is presumed to displace the chloride in the bridge with thiol ligands. The tethering of rhodium complexes to MCM-41 leads to reduced pore sizes, pore volumes and BET surface areas without altering the structural ordering of MCM-41. The MCM-41-tethered catalysts show distinct activities and resistance to rhodium leaching in cyclohexene hydroformylation under equimolar CO and H2 at 28 bar and 100 °C, depending on the nature of complexation of the supported donor ligands with the rhodium centre. The aminated MCM-41-tethered catalyst displays good activity, selectivity and recycling for the formation of cyclohexane carboxaldehyde. The mesoporous structure of MCM-41 remains stable during the reaction.
Synthesis of Novel Amidinato(amidine) Complexes of Molybdenum via Bis(amidine) Complexes
Authors: Yamaguchi Yoshitaka , Ogata Kenichi , Kobayashi Kimiko , Ito Takashi
Published: February 2004

The molybdenum complex [Mo(η3-allyl)Cl(CO)2(NCMe)2] (1) reacted with two equivalents of amidines, ArN=C(R)NHAr (R = H, CH3; Ar = C6H5, p-CH3–C6H4) (2), to give corresponding bis(amidine) complexes, [Mo(η3-allyl)Cl(CO)2(amidine)2] (3). Upon a treatment of bis(amidine)molybdenum complexes (3) with a base, such as n-butyllithium, complexes (4) bearing both amidinato and amidine ligands were formed and isolated as a yellow solid. The amidine ligand in complexes 4 was easily substituted by PEt3 to give amidinato(phosphine) complexes of molybdenum (5) as a red solid. These complexes were characterized spectroscopically as well as by X-ray analyses.
Imidazole Catalyzed Oxidations with Organic Peroxides: A Kinetic Study
Authors: Shawakfeh Khaled Q , Al-Ajlouni Ahmad M
Published: February 2004

Imidazole and 1-methylimidazole catalyze the oxidation of indigo dyes with m-chloroperoxybenzoic acid (MCPBA) in organic and mixed aqueous solutions. The kinetics of these reactions were studied in CH3OH/CH3CN and CH3OH/H2O solvent systems. The reaction rates decreased with the solvent polarity. The catalytically active species is proposed as an MCPBA–Im adduct which is in equilibrium with MCPBA and the imidazole. The equilibrium constant (K ∼ 70) for the formation of the MCPBA–Im adduct was determined in CH3OH/H2O (8:2). The catalyzed rates are at least three-orders of magnitude faster than the uncatalyzed rates. The electron-rich, 1-methylimidazole, increases the rate of oxidation of indigo blue via MCPBA more than imidazole itself. A mechanism similar to the Michaelis–Menten type was proposed for these reactions. The initial products from oxidation of indigo dyes by MCPBA are the epoxides, which undergo a slow ring-opening in the presence of water to form 1,2-diol products.
Stabilization of Carboxylate Anion with a NH···O Hydrogen Bond: Facilitation of the Deprotonation of Carboxylic Acid by the Neighboring Amide NH Groups
Authors: Onoda Akira , Yamada Yusuke , Takeda Jiro , Nakayama Yoshiki , Okamura Taka-aki , Doi Mototsugu , Yamamoto Hitoshi , Ueyama Norikazu
Published: February 2004

The formation of the NH···O hydrogen bonds of carboxylic acids, 2,6-(t-BuCONH)2C6H3COOH (1) and 2-t-BuCONH-6-MeC6H3COOH (2), carboxylate, [NEt4][2,6-(t-BuCONH)2C6H3COO] (3), and a mixed complex, [N(n-Pr)4][H{2,6-(t-BuCONH)2C6H3(COO)}2] (4), were determined by X-ray structure analysis, 1H NMR, and IR spectroscopy, both in the solid state and in solution. The amide NH group forms weak intramolecular hydrogen bond between the NH and O=C group, and no NH···OH hydrogen bond is formed in the carboxylic acid state. Carboxylate anion 3 forms a strong, intramolecular, partially-covalent hydrogen bond between NH···O− (anion). The strength of the NH···O hydrogen bonds is also maintained in a solution having a low dielectric constant. The pKa values for 1 and 2, measured in a micellar solution, indicated that one of the important triggers for deprotonation is a direct interaction toward the oxygen atom of the OH group with the amide NHs.
Study on the Structure Activity Relationships of NPTX-594, a Spider Toxin Belonging to the Type-B Acylpolyamine Structure
Authors: Wakamiya Tateaki , Kinoshita Tomohiko , Hattori Yoshihide , Yamaguchi Yoshihiro , Naoki Hideo , Corzo Gerardo , Nakajima Terumi
Published: February 2004

In order to elucidate the structure activity relationships of the spider toxin termed NPTX-594, eleven toxin analogs were designed and synthesized, and their paralytic activities against cricket were tested. As a result of the present study, it was clarified that the Lys residue binding to the 1-amino group of 4,8-diaza-1,12-dodecanediamine (Dada) in the molecule of NPTX-594 is not an essential requisite for toxicity, and can be replaced with neutral or basic amino acids without any considerable loss of the activity. However, the replacement of the Lys residue with acidic amino acid residues, such as Asp or Glu, resulted in an extreme loss of the biological activity.
The Barbier-Type Alkylation of Aldehydes with Alkyl Halides in the Presence of Metallic Strontium
Authors: Miyoshi Norikazu , Kamiura Koji , Oka Hiromi , Kita Akiko , Kuwata Rika , Ikehara Daitetsu , Wada Makoto
Published: February 2004

In the presence of metallic strontium, the Barbier-type alkylation of aldehydes with alkyl iodides proceeded smoothly at −15 °C under an argon atmosphere to afford the corresponding alkylated alcohols in moderate to good yields. The unusual addition reaction of ethyl benzoate with tert-butyl iodide took place to give the p-tert-butylated alkylated product (the 1,6-adduct of the benzoate) in 55% yield. Using strontium isopropoxide, the Meerwein–Ponndorf–Verley-type reduction of the aldehyde proceeded smoothly under reflux conditions in 2-propanol.
Hydroesterification of Vinylarenes Catalyzed by Palladium Complexes of Dialkylmonoaryl- and Monoalkyldiarylphosphines
Authors: Kawashima Yasutoyo , Okano Kentaro , Nozaki Kyoko , Hiyama Tamejiro
Published: February 2004

Hydroesterification of vinylarenes using a mixture of PdCl2 and monodentate phosphorus ligands as a catalyst was studied. As ligands, menthyldiphenylphosphine (MDPP), neomenthyldiphenylphosphine (NMDPP), and dicyclohexyl(phenyl)phosphine (Cy2PPh) were effective to obtain branched esters with high regioselectivity under the moderate reaction conditions without additives such as acids. Not only electronic effects but also steric effects of the cycloalkyl groups were revealed to be significant in order to achieve high catalytic activity. When (S)-2-dicyclopentylphosphino-2′-methoxy-1,1′-binaphthyl was used for the asymmetric hydroesterification of 2-methoxy-6-vinylnaphthalene, (S)-naproxen methyl ester was obtained with 53% ee.
Correlation between the g Tensors and the Nonplanarity of Porphyrin Rings in Desulfovibrio vulgaris Miyazaki F Cytochrome c3, Studied by Single Crystal EPR
Authors: Saitoh Takashi , Tachibana Yoshihiko , Higuchi Yoshiki , Hori Hiroshi , Akutsu Hideo
Published: February 2004

Single crystals of cytochrome c3 from Desulfovibrio vulgaris Miyazaki F were examined by EPR at cryogenic temperature. The principal values and the eigenvectors are determined. The four sets of EPR signals are directly assigned to the specific four hemes in the three-dimensional structure. The relative energy levels of the three d orbitals (dXY, dXZ, and dYZ) of each heme iron calculated from the obtained principal g values have shown that the energy gap between dXY and dπ is small for a heme with the S4-ruffled distortion (heme 1 and heme 2) while the energy gap is large for a heme with the S4-saddled distortion (heme 4). The determined g tensor orientations indicated that the principal g axes of heme 1, heme 2, heme 3, and heme 4 co-rotate with the imidazole planes of the sixth ligands.
Covalent Linking of Coordination-Organized Slipped Cofacial Porphyrin Dimers
Authors: Ohashi Atsushi , Satake Akiharu , Kobuke Yoshiaki
Published: February 2004

Coordination-organized porphyrin dimers of 5,15-bis[2-(allyloxycarbonyl)ethyl]- and bis[3-(allyloxy)propyl]-20-(1-methyl-2-imidazolyl)porphyrinatozinc were covalently linked by an intramolecular olefin metathesis reaction in excellent yields (93–98%). It was found that the yields of the intramolecular metathesis reaction depended strongly on the molecular length of the substituent at the 5 and 15 positions. Introducing longer 3-(allyloxycarbonyl)propyl and 4-(allyloxycarbonyl)butyl substituents decreased sharply the yields of the covalent linking reaction to 26% and 16%, respectively. The covalently linked dimers maintained their coordination structures even when dissolved in as polar a solvent as pyridine.
Isolation and Stereochemistry of Optically Active Selenoximines
Authors: Shimizu Toshio , Mitsuya Kazuhiko , Hirabayashi Kazunori , Kamigata Nobumasa
Published: February 2004

Asymmetric selenoximines were synthesized and their optical isomers were isolated for the first time by optical resolution using chromatography with a chiral column. The absolute configuration was determined by comparing their specific rotations and their circular dichroism spectra with those of a corresponding sulfur analogue with known absolute configuration. No racemization of the optically active selenoximines occurred under neutral, acidic, and basic conditions, and only decomposition was observed under aqueous acidic and basic conditions.
The Facile Preparation, Crystal Structure, and Chemical and Electrochemical Properties of 9-Anthryl-3-guaiazulenylmethylium Hexafluorophosphate
Authors: Takekuma Shin-ichi , Sasaki Kaori , Nakatsuji Miwa , Sasaki Masato , Minematsu Toshie , Takekuma Hideko
Published: February 2004

Reaction of guaiazulene (1) with anthracene-9-carbaldehyde in methanol in the presence of hexafluorophosphoric acid at 25 °C for 30 min gave the title compound 2 in 88% yield.
Dehydrogenation and Isomerization of Butane over Cr Catalysts Supported on H-SSZ-35 Type Zeolites
Authors: Inaba Megumu , Murata Kazuhisa , Saito Masahiro , Takahara Isao , Mimura Naoki , Hamada Hideaki , Kurata Yohei
Published: February 2004

The dehydrogenation and isomerization of butane to isobutene over Cr catalysts supported on zeolites were investigated. Although a zeolite support, especially with a low Si/Al2 ratio, favors the cracking of butane over its dehydrogenation and isomerization, due to strong solid acidity, the loading of Cr on a zeolite support enhances the dehydrogenation and isomerization of butane. H-SSZ-35 type zeolite, which has a one-dimensional cage-type channel structure, was hydrothermally synthesized using cis,cis,cis-N-methylhexahydrojulolidinium hydroxide as a structure-directing agent (SDA). We found that Cr/H-SSZ-35 (Si/Al2 = 500) showed moderate butane conversion and isobutene selectivity. As a result, the yield of isobutene (conversion of butane × selectivity of isobutene) was the highest among the catalysts used in this study. Its activity at 500 °C remained unchanged for 6 h. Our evidence suggests that butane was dehydrogenated over the zeolite support or Cr2O3 particles, and a proportion of the dehydrogenated products were isomerized to isobutene over the zeolite support.
Preparation and Characterization of LiCl-Occluded LiLSX Zeolite
Authors: Yoshida Satoshi , Harada Atsushi , Kamioka Kunikazu , Nakano Masao
Published: February 2004

LiCl-occluded LiLSX (Li exchanged Low Silica X zeolite with Si/Al = 1.0) was prepared by a heat treatment after evaporating a LiLSX or NaLSX slurry with LiCl, followed by lithium exchange in the case of NaLSX. The amount of occluded LiCl increased with increasing of the temperature. LiCl-occluded LiLSX prepared from NaLSX had a higher crystallinity than that prepared from LiLSX. The difference in crystallinity is explained as being related to the difference in the distortion of the skeleton structure of the zeolites. Chloride anions in high-crystallinity LiCl-occluded LiLSX were found to be located in sodalite cages by a Fourier synthesis of the powder X-ray diffraction pattern. The location of lithium cations was investigated based on the adsorption properties of nitrogen at room temperature and existing data on salt-occluded zeolites. Lithium cations in LiCl-occluded LiLSX are thought to simultaneously occupy the adjacent sites I and I′.
Electroreduction of Oxygen at a Pt/C-Modified Electrode with a Cobaltporphyrin Complex
Authors: Shentu Baoqing , Oyaizu Kenichi , Nishide Hiroyuki
Published: February 2004

Cobalt complexes that reversibly bind and release O2 functioned as O2 carriers, or O2-enriching media, at the surface of a cathode to enhance the current for the reduction of O2. The effect of the cobalt complex to accumulate O2 was evidenced by the higher open-circuit potential, which reflected the equilibrated concentration of O2 at the electrode surface. The combination of the cobalt complex and the conventional Pt/C catalyst resulted in a significant increase in the steady-state current for the four-electron reduction of O2, particularly at small overpotentials where typical fuel cells operate, based on the facilitated transport of O2 from the atmosphere to the catalyst at the electrode surface.
Preparation of Hydrogenated Surfactant/SC CO2 Micelles and Their Micropolarity Determination
Authors: Shervani Zameer , Liu Juncheng , Ikushima Yutaka
Published: February 2004

The influence of CO2-philicity and -phobicity of hydrogenated surfactants on preparation of reverse micelles in SC CO2 have been investigated for the first time. To this end, we used polyethylene glycol mono n-alkyl ether surfactants of different polar head groups and alkyl tails. Micelles prepared were characterized by dissolving 1-ethyl-4-methoxycarbonyl pyridinium iodide probe and recording its charge-transfer band in UV absorption region. From the transition energy of charge transfer band the polarity of the aqueous core of micelles was determined in terms of solvent polarity scale ET (30) values.
HIV-1 subtype dynamics over 10 years in a rural Ugandan cohort
Authors: Yirrell David L , Kaleebu Pontiano , Morgan Dilys , Hutchinson Sharon , Whitworth James A
Published: February 2004

Our objective was to monitor changes in the subtypes of HIV-1 infecting a rural Ugandan cohort where the spread of HIV-1 is by unprotected heterosexual contact and subtypes A and D predominate. Should one subtype be better able to spread we would anticipate a rise in incidence of one subtype at the expense of the other over a decade of study. We employed a natural history cohort, which had been established by the Medical Research Council in 1990 and subtyped virus from 90% (139) incident cases by DNA sequencing in two separate genes. We found that viral subtype had no predilection for males, females or age at infection and that between 1990 and 2000 there was no significant change in the relative number of different subtypes. The only significant trend was a reduction in the proportion of viruses classified as recombinant. This may reflect the overall decline in prevalence of HIV-1 in Uganda over this period.
A discriminative study of health-related quality of life assessment in HIV-1-infected persons living in Japan using the Multidimensional Quality of Life Questionnaire for persons with HIV/AIDS
Authors: Watanabe Megumi , Nishimura Koichi , Inoue Tomoko , Kimura Satoshi , Oka Shinichi ,   The Qol Research Group of the AIDS Clinical Centre and eight regional AIDS treatment hospitals in Japan
Published: February 2004

The aim of this study is to evaluate the discriminative properties of the Multidimensional Quality of Life Questionnaire for HIV infection (MQoL-HIV) and to determine those factors contributing to the health-related quality of life (HRQoL) of HIV-1 infected persons living in Japan. The MQoL-HIV, the Nottingham Health Profile (NHP) as a generic instrument, and the Center for Epidemiologic Studies-Depression Scale (CES-D) as a psychological measure were administered in 375 patients as a multiple-centre study. The score distribution of the MQoL-HIV showed a unimodal distribution. The Cronbach's α coefficient scored more than 0.7 in seven out of 10 domains, but was low in both the physical functioning and sexual functioning domains. There was a strong correlation between the CES-D and MQoL-HIV index scores (R-0.73). Relatively high coefficient values were found between psychiatric and nervous symptoms and the index score (R = -0.60). In total, the MQoL-HIV may possess discriminative properties.
Mortality and burden of disease in a cohort of HIV-seropositive adults in Nairobi, Kenya
Authors: Mwachari Christina W , Shepherd Bryan E , Cleopa Omondi , Odhiambo Joseph A , Cohen Craig R
Published: February 2004

The purposes of this study were to measure incidence and determine risk factors associated with opportunistic infections (OIs) and mortality among an HIV-infected cohort in Nairobi, Kenya. Three hundred and eighty-one seropositive ambulatory adults in Nairobi, Kenya were followed from 1997 to 2000 with participants visiting the clinic every two months and when acutely ill. Acute bronchitis was the most frequent diagnosis, followed by sexually transmitted infections, candida vaginitis (among women), fever, diarrhoea, pneumonia, HIV-associated skin rash, oral candidiasis and urinary tract infection. Associations between the frequency of these diagnoses including survival and sociodemographic factors and initial CD4 count were assessed. A CD4 count <200 cells/mL at recruitment was strongly associated with decreased survival (adjusted odds ratio = 3.0, 95% confidence interval 1.7-5.1). These findings may help to target high-risk populations and guide OI prevention and treatment strategies including decisions regarding initiation of antiretroviral therapy in sub-Saharan Africa.
An analysis of unsuccessful teleconsultations
Authors: Krupinski Elizabeth A , Barker Gail , Lopez Ana Maria , Weinstein Ronald S
Published: February 2004

Over six years, 4317 teleconsultations were scheduled in the Arizona Telemedicine Program. A total of 402 scheduled teleconsultations (9.3%) did not take place. A review showed that 254 were cancelled but eventually took place (5.9%), while 148 never took place (3.4%). The cost of a teleconsultation to the service provider was, at minimum, US$228. Telepsychiatry accounted for all the missed consultations that eventually took place, and 92% of these were from three of the six sites referring telepsychiatry patients. Pain management (23%) and psychiatry (21%) accounted for the largest proportions of teleconsultations that never took place. Telepsychiatry cases accounted for 71% of all unsuccessful consultations and accounted for only 34% of successful teleconsultations during the same period. Most missed teleconsultations had been scheduled as realtime sessions (84%). The most common reason for unsuccessful teleconsultations was that the patient did not attend (26%), followed by the patient having to be seen in person (17%). Although all referring sites had unsuccessful cases, certain sites accounted for more than others. These were sites that scheduled more telepsychiatry consultations than the others. The proportion of unsuccessful cases per site ranged from 4% to 17% of the total number of scheduled teleconsultations.
A mobile telemedicine unit for emergency and screening purposes: experience from north-west Russia
Authors: Uldal S B , Amerkhanov J , Manankova Bye S , Mokeev A , Norum J
Published: February 2004

A mobile telemedicine unit (MTU) was constructed for emergency and screening purposes in north-west Russia. The MTU included facilities for endoscopy, electrocardiography and digital photography. Data transmission was by ordinary telephone line. Between July and December 1999, the MTU was used in 48 incidents, involving 44 patients. The MTU was used to conduct 22 teleradiology examinations and 20 electrocardiograms were transmitted; in 10 cases still images of patients were transmitted and three consultations included tele-electroencephalography. Despite poor-quality analogue telephone lines, the MTU may prove useful in north-west Russia. Following the pilot study, the local Russian health administration stated that the MTU should always be included on emergency trips to the districts.
Evaluation of an accident and emergency teleconsultation service for north-east Scotland
Authors: Brebner E M , Brebner J A , Ruddick-Bracken H , Wootton R , Ferguson J , Palombo A , Pedley D , Rowlands A , Fraser S
Published: February 2004

We evaluated an accident and emergency teleconsultation service provided to 14 community hospitals in north-east Scotland. Each community hospital was equipped with a videoconferencing system and a document camera to allow transmission of radiographs. The network used 384 kbit/s ISDN connections. A total of 1392 teleconsultations were recorded during a 12-month study period. Seventy-seven per cent of patients ( n = 1072) were managed locally and 23% ( n = 320) were transferred to Aberdeen. The majority (95%) of teleconsultations were conducted on weekdays, and 90% of these occurred between the hours of 09:00 and 16:00. The mean delay in contacting a doctor was 9 min and the mean consultation time was 10 min. The majority of patients were suffering from fractures or suspected fractures of the limbs. Radiograph transmission was used in 75% of all teleconsultations. A high degree of satisfaction was recorded by all users of the service.
Reliability of Web-based teledermatology consultations
Authors: Oztas Murat Orhan , Calikoglu Emel , Baz Kiymet , Birol Ahu , Onder Meltem , Calikoglu Tamer , Kitapci Mehmet T
Published: February 2004

We studied the reliability of teledermatology diagnoses made using a Web-based system. Clinical photographs and information relating to 125 patients were placed on a Web server. Three dermatologists made the most likely diagnosis via a Web interface. The reference diagnosis was made in a face-to-face consultation with a fourth dermatologist; where appropriate it was confirmed histologically. The teledermatologists were correct in 57% of cases when viewing the images alone. Their diagnostic accuracy improved to 70% when additional clinical information was available. The rate of agreement between the teledermatologists ranged from 44% to 70% (kappa= 0.22–0.32). Seventy-seven per cent of the patients were correctly diagnosed by at least two dermatologists when clinical information was provided. A Web-based system appears to be reliable for teledermatology. A single well trained teledermatologist may give better results than a group of less well trained clinicians.
Telepathology using immunofluorescence/immunoperoxidase microscopy
Authors: Lanschuetzer C M , Pohla-Gubo G , Schafleitner B , Hametner R , Hashimoto T , Salmhofer W , Bauer J W , Hintner H
Published: February 2004

We evaluated low-cost, store-and-forward telepathology interpretation of digital images of skin sections stained immunohistochemically, using immunofluorescence (IF) and immunoperoxidase (IP). The sample comprised 17 patients with skin diseases characterized by cutaneous deposition of immunoglobulins, fibrinogen or complement components. Up to 11 digital IF or IP images (median 3) were transferred via email to centres in Graz, Austria, and Kurume, Japan. Both remote centres had expertise in reading immunohistochemical specimens. Although image files were relatively small (approximately 100 kByte), the IF images were of high quality and they were well suited to static telepathology. There was agreement on the diagnoses made by the local and both remote centres by physicians experienced in IF/IP microscopy in 14 of 17 cases (82%). These results suggest that telepathology evaluation of immunohistochemical specimens may be a useful procedure for the discussion of unusual skin disorders, training purposes and second-opinion consultations on difficult cases from centres of excellence in immunohistochemical diagnosis.
Bleeding and Thrombosis in High-Risk Renal Transplantation Candidates Using Heparin
Authors: Mathis A Scott , Davé Nisha , Shah Nita K , Friedman Gary S
Published: February 2004

BACKGROUND

Heparin can reduce the risk of renal artery/vein thrombosis in renal transplant patients with hypercoagulable states (HCS), but is associated with a high bleeding risk. Little is known about risk factors for this bleeding risk or the optimal anticoagulation target.

OBJECTIVE

To determine factors associated with this bleeding risk and determine the optimal partial thromboplastin time (PTT) ratio.

METHODS

We retrospectively reviewed medical records of consecutive adult renal transplant recipients administered heparin for perioperative renal thrombosis prevention (1998–2002).

RESULTS

Twenty-eight (3.86%) of 725 consecutive renal transplant recipients received heparin to prevent renal thrombosis. Eighteen patients (64.3%) had clinically important bleeding (14 major bleeding). Patients with and without bleeding were similar in baseline demographic characteristics and overall mean PTT. Bleeding occurred at a mean PTT ratio of 2.5 ± 1, higher than the overall mean in bleeders and nonbleeders (p = 0.001). Among postoperative characteristics, higher maximum PTT (p = 0.052) and prolonged surgical antibiotic prophylaxis (p = 0.053), particularly with cefotetan (p = 0.091), trended toward a significant association with bleeding. Two renal thrombotic episodes occurred, both at PTT ratios <1.5. A PTT ratio of 1.5–1.9 resulted in no thrombosis and ≤4.2% bleeding.

CONCLUSIONS

The benefits and risks of therapeutic heparin anticoagulation in renal transplant patients with HCSs were confirmed. Higher PTTs and cefotetan antibiotic surgical prophylaxis could contribute to bleeding. The optimal PTT ratio appeared to be 1.5–1.9 to prevent thrombosis and limit bleeding risk.
Identification by Proteomic Analysis of Calreticulin as a Marker for Bladder Cancer and Evaluation of the Diagnostic Accuracy of Its Detection in Urine
Authors: Kageyama Susumu , Isono Takahiro , Iwaki Hideaki , Wakabayashi Yoshihiko , Okada Yusaku , Kontani Keiichi , Yoshimura Koji , Terai Akito , Arai Yoichi , Yoshiki Tatsuhiro
Published: February 2004

Background: New methods for detection of bladder cancer are needed because cystoscopy is both invasive and expensive and urine cytology has low sensitivity. We screened proteins as tumor markers for bladder cancer by proteomic analysis of cancerous and healthy tissues and investigated the diagnostic accuracy of one such marker in urine.

Methods: Three specimens of bladder cancer and healthy urothelium, respectively, were used for proteome differential display using narrow-pH-range two-dimensional electrophoresis. To evaluate the presence of calreticulin (CRT) as detected by Western blotting, we obtained 22 cancerous and 10 noncancerous surgical specimens from transurethral resection or radical cystectomy. To evaluate urinary CRT, we collected 70 and 181 urine samples from patients with and without bladder cancer, respectively. Anti-CRT COOH-terminus antibody was used to detect CRT in tissue and urine.

Results: Proteomic analysis revealed increased CRT (55 kDa; pI 4.3) in cancer tissue. Quantitative Western blot analysis showed that CRT was increased in cancer tissue (P = 0.0003). Urinary CRT had a sensitivity of 73% (95% confidence interval, 62–83%) at a specificity of 86% (80–91%) for bladder cancer in the samples tested.

Conclusions: Proteomic analysis is useful in searching for candidate proteins as biomarkers and led to the identification of urinary CRT. The diagnostic accuracy of urinary CRT for bladder cancer appears comparable to that of Food and Drug Administration-cleared urinary markers, but further studies are needed to determine its diagnostic role.
A Strategic Approach to Internationalization: A Traditional versus a “Born-Global” Approach
Authors: Chetty Sylvie , Campbell-Hunt Colin
Published: February 2004

This article is based on a study of 16 in-depth case histories of New Zealand firms. It uses both the traditional and the “born-global” approaches as a framework to study the internationalization processes of the firms. The authors use the histories to conduct a systematic analysis of the extent to which firms that might be categorized as following a traditional or born-global internationalization path differ in the strategies they have used and in their prior motivations and capabilities. The main findings are that many attributes of the born-global model also characterize firms that began their internationalization along traditional lines but were radically transformed in the process of achieving global reach. This study identifies the consequences of rapid international growth, referred to as “the gusher,” among these firms and the destabilizing effects of the experience as the firm is taken in unexpected directions. The authors conclude that the born-global model has much in common with the internationalization of small entrepreneurial firms and that its most distinctive elements lie in the model's relevance to an increasingly globalized world economy and in the more aggressive learning strategies that are required to follow this path.
Retail Pricing Strategies in Recession Economies: The Case of Taiwan
Authors: Chou Ting-Jui , Chen Fu-Tang
Published: February 2004

In a recession economy, consumers tend to be more sensitive about price, and firms have difficulty obtaining necessary resources for effective pricing. However, previous studies into pricing appear to overlook the possible effect of economic environment on the effectiveness of a pricing strategy. By observing the current recession and the resultant price war in Asian countries, the authors examine marketing decisions by retailers in a recession economy. The authors propose a contingent model, based on organizational resources and consumer price consciousness, to guide the examination of the strategy–performance bond. The results show that only resource-abundant retailers are able to use strategies proposed in this study to thrive in a recession. A value-centric strategy outperforms all other approaches.
Excitonic Coupling Strength and Coherence Length in the Singlet and Triplet Excited States of meso–meso Directly Linked Zn(II)porphyrin Arrays
Authors: Ha Jeong‐Hyon , Cho Hyun Sun , Song Jae Kyu , Kim Dongho , Aratani Naoki , Osuka Atsuhiro
Published: February 2004

Excitation‐energy transport (EET) phenomena in meso–meso directly linked Zn(II)porphyrin arrays in the singlet and triplet excited states were investigated with a view to electronic coupling strength and coherence length by steady‐state and time‐resolved spectroscopic measurements. To investigate energy transfer in the triplet states, we modified the Zn(II)porphyrin arrays with bromo substituents at both ends. The coupling strength of the Soret bands of the arrays was estimated to be about 2200 cm−1, and that of the Q bands is about 570 cm−1. The coherence length in the S1 state of the Zn(II)porphyrin arrays was determined to be 4–5 porphyrin units, which is comparable to that of the well‐ordered two‐dimensional circular structure B850 in the peripheral light‐harvesting antenna (LH2) in photosynthetic purple bacteria. This indicates that the Zn(II)porphyrin arrays are well suited for mimicking natural light‐harvesting antenna complexes. On the other hand, the rate of energy transfer in the triplet state is estimated to be on the order of 100 μs−1, and the very weak coupling between the triplet states (ca. 0.003 cm−1), indicates that the triplet excitation energy is essentially localized on a single porphyrin moiety.
In Situ Spectroscopic Analysis of Nanocluster Formation
Authors: Wang Jia , Boelens Hans F. M. , Thathagar Mehul B. , Rothenberg Gadi
Published: February 2004

The importance of small metal clusters in catalysis and the problems in understanding the clustering process in solution are outlined. A new analysis method for UV/Vis spectra is presented and applied to monitor the kinetics of ion reduction and cluster formation in situ. This method, which is based on a combination of two chemometric techniques, takes into account the entire UV/Vis spectrum and offers better interpretation possibilities than the traditional “band‐assignment” approach. This is particularly true for nanoclusters because these have significant spectral contributions also outside the broad plasmon band that is usually associated with them. The reduction of palladium, gold, and silver ions and the formation of the corresponding clusters is monitored in the presence of two different reducing agents, sodium borohydride and tetraoctylammonium acetate. While Pd2+ is found to reduce and cluster directly, the spectral decomposition of the Au3+ reduction profiles shows two species corresponding to the Au+ intermediate and the Au0 clusters. The rates of reduction and clustering for Pd, Au, and Ag are compared and the possibilities of synthesising multimetallic clusters of these metals by coreduction are discussed.
Ultrafast Time‐Resolved Transient Structures of Solids and Liquids by Means of Extended X‐ray Absorption Fine Structure
Authors: Tomov Ivan V. , Rentzepis Peter M.
Published: February 2004

Detection of ultrafast transient structures and the evolution of ultrafast structural intermediates during the course of reactions has been a long standing goal of chemists and biologists. This article will be restricted to nanosecond, picosecond and shorter time‐resolved extended X‐ray absorption fine structure (EXAFS) studies, its aim being to present the progress and problems encounter in measurements and understanding the structure of transients. The recent advances in source technology has stimulated a wide variety of novel experiments using both synchrotrons and smaller laboratory size systems. With more efficient X‐ray lenses and detectors many of the previously difficult experiments to perform, because of the exposure time required and weak signals, will now be easily performed. The experimental system for the detection of ultrafast time‐resolved EXAFS spectra of molecules in liquids is described and the method for the analysis of EXAFS spectra to yield transient structures is given. We believe that utilizing our table‐top ultrafast X‐ray source and the polycapillary optics in conjunction with dispersive spectrometer and charge coupled devices (CCD) we will be able to determine the structure of many reaction intermediates and excited states of chemical and biological molecules in solid and liquid state.
How To Make Ohmic Contacts to Organic Semiconductors
Authors: Shen Yulong , Hosseini Ahmad R. , Wong Man Hoi , Malliaras George G.
Published: February 2004

The process of charge injection plays an important role in organic semiconductor devices. We review various experimental techniques that allow injection to be separated from other competing processes, and quantify the injection efficiency of a contact. We discuss the dependence of the injection efficiency on parameters such as the energy barrier at the interface, the carrier mobility of the organic semiconductor, its carrier density (doping level), the presence of mobile ions, and the sample geometry. Based on these findings, we outline guidelines for forming ohmic contacts and present examples of contact engineering in organic semiconductor devices.
On the effectiveness of alternative paths in QoS routing
Authors: Jia Yanxia , Nikolaidis Ioanis , Gburzynski Pawel
Published: February 2004

We propose a routing strategy in which connection requests with specific bandwidth demands can be assigned to one of several alternative paths connecting the source to the destination. The primary goal of this multiple‐path approach is to compensate for the inaccuracy of the knowledge available to routing nodes, caused by the limited frequency of link state (LS) information exchanges. We introduce a collection of K‐shortest path routing schemes and investigate their performance under a variety of traffic conditions and network configurations. We subsequently demonstrate that K‐shortest path routing offers a lower blocking probability in all scenarios and more balanced link utilization than other routing methods discussed in the literature. With our approach, it is possible to reduce the frequency of link state exchanges, and the incurred bandwidth overhead, without compromising the overall performance of the network. Based on the proposed routing scheme, we investigate different link state dissemination algorithms, which are aimed at reducing the communication overhead by prioritizing the scope and differentiating the qualitative content of LS update messages. Copyright © 2004 John Wiley & Sons, Ltd.
Parlay‐based service provision in circuit‐ and packet‐switched telecommunications networks
Authors: Papadakis Andreas E. , Chaniotakis Emmanuel S. , Giannakakis Prokopis E. , Tselikas Nikolaos D. , Venieris Iakovos S.
Published: February 2004

The spectrum of potential value added services over Internet telephony is wide, but the current service provision solutions are inadequate or proprietary. The nature of Internet differs significantly from that of circuit switched network, however, VoIP architectures can capitalize service control architectures in the PSTN world. We describe such an architecture based on the intelligent network and the Parlay, employing distributed objects and mobile agents as enabling technologies. This architecture has been implemented in the PSTN and the Internet and it has provided a framework for service provisioning, augmenting the space of supported services. Copyright © 2004 John Wiley & Sons, Ltd.
A downlink beamforming method for multimedia CDMA/TDD systems
Authors: Hara Yoshitaka , Park Duk‐Kyu , Kamio Yukiyoshi
Published: February 2004

This paper proposes a downlink beamforming method in TDD (time division duplex)‐type CDMA (code division multiple access) system. The proposed beamforming is a method that can satisfy various requirements of the user for SINR (signal‐to‐interference‐plus‐noise power ratio) in the multimedia communications environment while trying to minimize the total transmitted power from the base station. In the proposed method, the beamforming is performed with allowance for the SINR required by the user and the number of fingers in RAKE reception at the terminal. In the beamforming process it is desirable to reduce the total transmitted power from the base station in transmitted power control. As a result of performance evaluation, we see that the proposed method can improve the system capacity in an environment where terminals with various transmission rates coexist. In particular, when the traffic is concentrated to a cell, the proposed beamforming is shown to function effectively. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(6): 61–75, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10062
Performance evaluation of OFDM with a nonlinear distortion compensation technique using partial transmit sequence and predistortion
Authors: Horiuchi Takaaki , Yang Weizu , Ohtsuki Tomoaki , Sasase Iwao
Published: February 2004

As a conventional method of compensating the nonlinear distortion in OFDM (orthogonal frequency division multiplexing), LCP‐COFDM (linearized constant peak‐power coded OFDM) has been proposed. In LCP‐COFDM, however, the signal power is reduced by the linear compression (constant peak amplitude) process, which degrades the noise immunity and degrades the BER (bit error rate) characteristic. Consequently, this paper proposes a nonlinear distortion compensation scheme in which the BER is improved by combining LCP‐COFDM with the partial transmit sequence. As a result of performance evaluation by computer simulation, it is shown that the proposed method can improve the BER with nearly the same out‐band radiation reduction as conventional LCP‐COFDM. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(6): 34–42, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10129
A proposal of multihop mesh network architecture featuring adaptive network control for broadband fixed wireless access systems
Authors: Kishi Yoji , Tabata Keita , Konishi Satoshi , Nomoto Shinichi
Published: February 2004

As a means of flexibly providing large‐capacity access infrastructure at a low cost, the broadband fixed wireless access (BFWA) system using millimeter‐wave and quasi‐millimeter‐wave frequencies is promising. In general, wireless channel quality variations are significant due to rainfall in wireless systems using millimeter‐wave and quasi‐millimeter‐wave frequencies. Hence, deterioration of the channel working rate is a problem. In this paper, a multihop wireless access system with a mesh configuration is proposed that can deploy a millimeter‐ and quasi‐millimeter‐wave BFWA system at a high quality and a high density. In the proposed system, deterioration of the channel working rate due to wireless channel quality variations is avoided. In addition, the capacity is maximized by adaptively assigning the network resources for variations of the traffic demand and wireless channel transmission capacity. Further, as an adaptive control used in the proposed system, wireless channel assignment for a wireless link and load distribution among several paths within the mesh network are discussed. The problem is formulated as a mixed nonlinear optimization problem. In addition, a heuristic solution is proposed for solving the problem within a realistic time for a network of the anticipated size. The proposed algorithm is applied to a mesh network and the behavior and the performance of the algorithm are evaluated to prove its effectiveness. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(6): 22–33, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10133
Exact analysis of performance of selective‐repeat ARQ scheme with limited retransmissions
Authors: Fujii Shumji , Hayashida Yukuo
Published: February 2004

This paper considers the selective‐repeat ARQ scheme, which is a typical error control scheme used in data communication systems, and analyzes the performance of the scheme in which the number of frame retransmissions is limited. In the proposed scheme, messages such as image for which information loss can be tolerated to some extent are transmitted after being divided into multiple frames. If the retransmission of a frame reaches the preset limit, the receiver accepts that frame even if an error is present, and the error is processed as noise or distortion. By this scheme, an upper limit can be defined for the time from the start to the end of the message transmission. This paper analyzes the proposed scheme using the discrete‐time queuing model and derives the distribution of the message transmission delay. The throughput and the required receiver buffer capacity are also derived. It is shown by numerical examples that the throughput can be improved and the receiver buffer capacity can be reduced. If the strict analysis is continued, however, the state space of the Markov chain is enlarged with the increase in the number of parameters such as the round‐trip propagation delay and the number of message divisions. Thus, the numerical calculation of the transmission delay becomes difficult. The approximate analysis of the message transmission delay and its properties are discussed in Ref. 1. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(6): 1–11, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10181