bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Antiviral Activities of Some 4,4′‐Dihydroxytriphenylmethanes.
Authors: Mibu Nobuko , Yokomizo Kazumi , Uyeda Masaru , Sumoto Kunihiro
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Sulfur‐Rich Oxides SnO and SnO2 (n > 1)
Authors: Steudel Ralf
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Brazing a Mixed Ionic/Electronic Conductor to an Oxidation Resistant Metal
Authors: Weil K. Scott , Hardy John S.
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Photochemical Reactivity of Pyridones
Authors: Sieburth Scott McN.
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Asymmetric Syntheses Aided by Biocatalysts
Authors: Chen Pei‐Ran , Gu Jian‐Xin , Wei Zhi‐Liang , Han Shi‐Qing , Li Zu‐Yi , Lin Guo‐Qiang
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Catalytic Enantioselective Aza Diels—Alder Reactions
Authors: Kobayashi Shu
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Development of Catalytic Carbon Radical Generation and Its Application to Organic Synthesis
Authors: Ishii Yasutaka , Sakaguchi Satoshi
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Studies on π‐Face Selective Additions with 3,4‐Di‐tert‐butylthiophene 1‐Oxide and 1‐Imide
Authors: Nakayama Juzo
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Novel Approach to Respiratory Pharmacology—Pharmacological Basis of Cough, Sputum and Airway Clearance
Authors: Miyata Takeshi
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Protection (and Deprotection) of Functional Groups in Organic Synthesis by Heterogeneous Catalysis
Authors: Sartori Giovanni , Ballini Roberto , Bigi Franca , Bosica Giovanna , Maggi Raimondo , Righi Paolo
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Stabilization of p‐Block Organoelement Terminal Hydroxides, Thiols, and Selenols Requires Newer Synthetic Strategies
Authors: Roesky Herbert W. , Murugavel Ramaswamy , Walawalkar Mrinalini G.
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Absolute Conformation Revisited: Experimental Approach
Authors: Oki Michinori , Toyota Shinji
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
The Pauson—Khand Reaction, a Powerful Synthetic Tool for the Synthesis of Complex Molecules
Authors: Blanco‐Urgoiti Jaime , Anorbe Loreto , Perez‐Serrano Leticia , Dominguez Gema , Perez‐Castells Javier
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Recent Highlights in Electrophilic Fluorination with 1‐Chloromethyl‐4‐fluoro‐1,4‐diazoniabicyclo[2.2.2]octane Bis(tetrafluoroborate)
Authors: Singh Rajendra P. , Shreeve Jean'ne M.
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Dynamics of Antioxidant Action of Vitamin E
Authors: Niki Etsuo , Noguchi Noriko
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Kinetics and Spectroscopy of Substituted Phenylnitrenes
Authors: Gritsan Nina P. , Platz Matthew S.
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Norrish Type II Processes of Ketones: Influence of Environment
Authors: Hasegawa Tadashi
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Antitumor Activity of Silatranes
Authors: Voronkov M. G. , Baryshok V. P.
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Ring Currents in Large [4n + 2]‐Annulenes
Authors: Soncini Alessandro , Fowler Patrick W. , Jenneskens Leonardus W.
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Localization and Reversal of Paratropic Ring Currents in Molecules with Formal Antiaromatic Electron Counts
Authors: Havenith Remco W. A. , Engelberts Jeroen J. , Fowler Patrick W. , Steiner Erich , van Lenthe Joop H. , Lazzeretti Paolo
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Stability of Tubulenes
Authors: Diudea Mircea V.
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Molecular Recognition: Synthetic Receptors by Rational Design and Targeted Synthesis
Authors: Davis A. P.
Published: March 2004

For Abstract see ChemInform Abstract in Full Text.
Phase II study of neoadjuvant 1, 3‐bis (2‐chloroethyl)‐1‐nitrosourea and temozolomide for newly diagnosed anaplastic glioma
Authors: Chang Susan M. , Prados Michael D. , Yung W. K. Alfred , Fine Howard , Junck Larry , Greenberg Harry , Robins H. Ian , Mehta Minesh , Fink Karen L. , Jaeckle Kurt A. , Kuhn John , Hess Kenneth , Schold Clifford
Published: March 2004

BACKGROUND

Temozolomide (TMZ) and 1, 3‐bis (2‐chloroethyl)‐1‐nitrosourea (BCNU) are reported to be active agents in anaplastic glioma (AG). TMZ has also been shown to deplete alkyltransferase, a DNA repair enzyme that contributes to nitrosourea resistance. The objective of the current study was to determine the efficacy and toxicity profile of a combination of these agents before radiotherapy in newly diagnosed AG.

METHODS

Eligibility criteria included histologically confirmed newly diagnosed AG with measurable enhancing disease, a Karnofsky performance score (KPS) ≥ 60, normal pulmonary function, and normal laboratory parameters. In addition, informed consent was obtained from all patients. BCNU given at a dose of 150 mg/m2 intravenously was followed after 2 hours by TMZ given at a dose of 550 mg/m2 orally on Day 1 of a 42‐day cycle to a maximum of 4 cycles, unless there was tumor progression or unacceptable toxicity.

RESULTS

Forty‐one eligible patients were accrued. Their median age was 40 years. Seventy‐six percent of patients had a KPS of 90–100. The histology was 81% anaplastic astrocytoma, 12% anaplastic oligodendroglioma, and 7% mixed tumors. Twenty‐two percent of patients did not complete 4 cycles because of toxicity, mainly hematologic. Forty‐six percent of patients experienced Grade 3 or 4 (according to National Cancer Institute Common Toxicity Criteria) thrombocytopenia. Twenty percent had Grade 4 granulocytopenia. Two patients died while receiving therapy, 1 of progressive disease and the other of Pneumocystis carinii pneumonia. The complete and partial response rates were 2% and 27% respectively. An additional 54% of patients had stable disease. Seventeen percent developed progressive disease (10% after the first cycle and 7% after the second cycle).

CONCLUSIONS

This neoadjuvant strategy was associated with significant myelosuppression and a modest response rate in patients with newly diagnosed AG. Cancer 2004. © 2004 American Cancer Society.
Cancer screening and the periodic health examination
Authors: Smith Robert A. , Wender Richard C.
Published: March 2004

In this issue of Cancer, Chen et al. report outcomes from an integrated model of multiphasic chronic disease screening in Taiwan. The design and outcomes of the Keelung Community‐based Integrated Screening program are noteworthy for several reasons and should reopen the debate not only regarding the worth, but also the protocol for periodic preventive health examinations.

See also pages 000–000.
Community‐based multiple screening model
Authors: Chen Tony Hsiu‐Hsi , Chiu Yueh‐Hsia , Luh Dih‐Ling , Yen Ming‐Fang , Wu Hui‐Min , Chen Li‐Sheng , Tung Tao‐Hsin , Huang Chih‐Chung , Chan Chang‐Chuan , Shiu Ming‐Neng , Yeh Yen‐Po , Liou Horng‐Huei , Liao Chao‐Sheng , Lai Hsin‐Chih , Chiang Chun‐Pin , Peng Hui‐Ling , Tseng Chuen‐Den , Yen Ming‐Shyen , Hsu Wei‐Chih , Chen Chih‐Hung
Published: March 2004

BACKGROUND

Multiple disease screening may have several advantages over single disease screening because of the economics of scale, with the high yield of detecting asymptomatic diseases, the identification of multiple diseases or risk factors simultaneously, the enhancement of the attendance rate, and the efficiency of follow‐up.

METHODS

An integrated model of community‐based multiple screening was designed and conducted between 1999 and 2001 in Keelung, Taiwan. The authors used a Papanicolaou (Pap) smear screening program as a base to integrate other screening regimens encompassing four other neoplastic diseases and three nonneoplastic chronic diseases. Screening methods, the interscreening interval, and the follow‐up for each screening regimen were designed based on evidence‐based literature and current national screening policy.

RESULTS

A total of 42,387 subjects participated in the screening activities. A 25% increase in the attendance rate for Pap smear screening was demonstrated after the introduction of multiple disease screening programs. At the first screen, this program yielded a total of 677 asymptomatic neoplasms (16.0 per 1000), including a large proportion of precancerous lesions and small presymptomatic tumors without lymph node involvement. The association between the occurrence of neoplasm and the presence of comorbid nonneoplastic chronic disease was found to be statistically significant (odds ratio, 1.64; 95% confidence interval, 1.38–1.94 [P < 0.05]). The authors also identified 5314 subjects with metabolic syndrome who were at a greater risk for colorectal and oral neoplasias.

CONCLUSIONS

The results of the current study demonstrate that an outreach and community‐based multiple screening program not only enhances attendance rates but also has a high yield of early cases of various diseases simultaneously, and provides a natural opportunity to elucidate the correlation between neoplastic disease and nonneoplastic chronic disease. Cancer 2004. © 2004 American Cancer Society.
Memory and a priori best strategy in complex adaptive systems
Authors: Quito Marcelino , Monterola Christopher , Saloma Caesar
Published: March 2004

We employ an agent‐based model to show that memory and the absence of an a priori best strategy are sufficient for self‐segregation and clustering to emerge in a complex adaptive system with discrete agents that do not compete over a limited resource nor contend in a winner‐take‐all scenario. An agent starts from a corner of a two‐dimensional lattice and aims to reach a randomly selected site in the opposite side within the shortest possible time. The agent is isolated during the course of its journey and does not interact with other agents. Time‐bound obstacles appear at random lattice locations and the agent must decide whether to challenge or evade any obstacle blocking its path. The agent is capable of adapting a strategy in dealing with an obstacle. We analyze the dependence of strategy‐retention time with strategy for both memory‐based and memory‐less agents. We derive the equality spectrum to establish the environmental conditions that favor the existence of an a priori best strategy. We found that memory‐less agents do not polarize into two opposite strategy‐retention time distributions nor cluster toward a center distribution. © 2004 Wiley Periodicals, Inc. Complexity 9: 41–46, 2004
Automated microscopy identifies estrogen receptor subdomains with large‐scale chromatin structure unfolding activity
Authors: Carpenter Anne E. , Ashouri Anousheh , Belmont Andrew S.
Published: March 2004

Background

Recently, several transcription factors were found to possess large‐scale chromatin unfolding activity; these include the VP16 acidic activation domain, BRCA1, E2F1, p53, and the glucocorticoid and estrogen steroid receptors. In these studies, proteins were fluorescently labeled and targeted to a multimerized array of DNA sequences in mammalian cultured cells, and changes in the appearance and/or size of the array were observed. This type of experiment is impeded by the low throughput of traditional microscopy.

Methods

We report the application of automated microscopy to provide unattended, rapid, quantitative measurements of fluorescently labeled chromosome regions.

Results

The automated image collection routine produced results comparable to results previously obtained by manual methods and was significantly faster. Using this approach, we identified two subdomains within the E domain of estrogen receptor α capable of inducing large‐scale chromatin decondensation.

Conclusions

This work confirms that, like BRCA1, the activation function 2 region of the estrogen receptor has more than one distinct chromatin unfolding domain. In addition, we demonstrate the feasibility of using automated microscopy as a high‐throughput screen for identifying modulators of large‐scale chromatin folding. The Supplementary Material referred to in this article can be found at the CYTO Part A website (http://www.interscience.wiley.com/jpages/0196‐4763/suppmat/v58A.html) © 2004 Wiley‐Liss, Inc.
Suppression of photobleaching‐induced artifacts in frequency‐domain FLIM by permutation of the recording order
Authors: van Munster Erik B. , Gadella Theodorus W.J.
Published: March 2004

Background

Photobleaching can lead to significant errors in frequency‐domain fluorescence lifetime imaging microscopy (FLIM). Existing correction methods for photobleaching require additional recordings and processing time and can result in additional noise. A method is introduced that suppresses the effects of photobleaching without the need for extra recordings or processing.

Methods

Existing bleach correction methods and the method introduced in this report whereby the recording order of the phases is permuted were compared using numerical simulations.

Results

Certain orders were found to make measurements virtually insensitive to photobleaching. At 12 recordings, errors in measured phase and modulation depth decreased by a factor 512 and 393, respectively, compared to recordings using sequential recording order. The optimal order is independent of modulation depth, phase, and extent of photobleaching. Thus, the same order can be used for practically all situations. Application of the method in FLIM measurements of EYFP‐transfected HeLa cells was found effectively to suppress photobleaching induced artifacts.

Conclusions

In view of the ease of implementation, its inherent robustness, and the possibility to still apply existing correction methods afterward, there is no good reason not to use the permuted recording order presented in this report instead of a sequential order. © 2004 Wiley‐Liss, Inc.
Assessment of histone H2AX phosphorylation induced by DNA topoisomerase I and II inhibitors topotecan and mitoxantrone and by the DNA cross‐linking agent cisplatin
Authors: Huang Xuan , Okafuji Masaki , Traganos Frank , Luther Ed , Holden Elena , Darzynkiewicz Zbigniew
Published: March 2004

Background

DNA double‐strand breaks (DSBs) in chromatin, whether induced by radiation, antitumor drugs, or by apoptosis‐associated (AA) DNA fragmentation, provide a signal for histone H2AX phosphorylation on Ser‐139; the phosphorylated H2AX is denoted γH2AX. The intensity of immunofluorescence (IF) of γH2AX was reported to reveal the frequency of DSBs in chromatin induced by radiation or by DNA topoisomerase I (topo 1) and II (topo 2) inhibitors. The purpose of this study was to further characterize the drug‐induced (DI) IF of γH2AX, and in particular to distinguish it from AA γH2AX IF triggered by DNA breaks that occur in the course of AA DNA fragmentation.

Methods

HL‐60 cells in cultures were treated with topotecan (TPT), mitoxantrone (MTX), or with DNA cross‐linking drug cisplatin (CP); using multiparameter flow and laser‐scanning cytometry, induction of γH2AX was correlated with: 1) caspase‐3 activation; 2) chromatin condensation, 3) cell cycle phase, and 4) AA DNA fragmentation. The intensity of γH2AX IF was compensated for by an increase in histone/DNA content, which doubles during the cell cycle, and for the “programmed” H2AX phosphorylation, which occurs in untreated cells.

Results

In cells treated with TPT or MTX, the increase in DI‐γH2AX IF peaked at 1.5 or 2 h, and was maximal in S‐ or G1‐phase cells, respectively, for each drug. In cells treated with CP, compared with TPT, the γH2AX IF was less intense, peaked later (3 h) and showed no cell cycle–phase specificity. In the presence of phosphatase inhibitor calyculin A, a continuous increase in the TPT‐induced γH2AX IF was still seen past 1.5 h, and after 3 h γH2AX IF was 2.7‐ to 3.4‐fold higher than in the absence of the inhibitor. The AA γH2AX IF was distinguished from the DI‐γH2AX IF by: 1) its greater intensity; 2) its prevention by caspase inhibitor zVAD‐FMK; and 3) the concurrent activation of caspase‐3 in the same cells. A decrease in AA γH2AX IF coinciding with AA chromatin condensation was seen in the late stages of apoptosis.

Conclusions

Multiparameter analysis of γH2AX IF, caspase‐3 activation, cellular DNA content, and chromatin condensation allowed us to distinguish the DI from AA H2AX phosphorylation and relate them to the cell cycle phase and stage of apoptosis. With a comparable degree of ds DNA breaks, the cells arrested at the G1 or G2/M checkpoint were less prone to undergo apoptosis than the cells replicating DNA. H2AX phosphorylation seen in CP‐treated cells may be associated with DNA repair that involves nucleotide excision repair (NER) and nonhomologous end joining (NHEJ). When the primary drug‐induced lesions do not involve ds DNA breaks, but ds DNA breaks are formed during DNA repair, as in the case of CP, analysis of H2AX phosphorylation may reflect extent of the repair process. © 2004 Wiley‐Liss, Inc.
Design and validation of a tool for neurite tracing and analysis in fluorescence microscopy images
Authors: Meijering E. , Jacob M. , Sarria J.‐C.F. , Steiner P. , Hirling H. , Unser M.
Published: March 2004

Background

For the investigation of the molecular mechanisms involved in neurite outgrowth and differentiation, accurate and reproducible segmentation and quantification of neuronal processes are a prerequisite. To facilitate this task, we developed a semiautomatic neurite tracing technique. This article describes the design and validation of the technique.

Methods

The technique was compared to fully manual delineation. Four observers repeatedly traced selected neurites in 20 fluorescence microscopy images of cells in culture, using both methods. Accuracy and reproducibility were determined by comparing the tracings to high‐resolution reference tracings, using two error measures. Labor intensiveness was measured in numbers of mouse clicks required. The significance of the results was determined by a Student t‐test and by analysis of variance.

Results

Both methods slightly underestimated the true neurite length, but the differences were not unanimously significant. The average deviation from the true neurite centerline was a factor 2.6 smaller with the developed technique compared to fully manual tracing. Intraobserver variability in the respective measures was reduced by a factor 6.0 and 23.2. Interobserver variability was reduced by a factor 2.4 and 8.8, respectively, and labor intensiveness by a factor 3.3.

Conclusions

Providing similar accuracy in measuring neurite length, significantly improved accuracy in neurite centerline extraction, and significantly improved reproducibility and reduced labor intensiveness, the developed technique may replace fully manual tracing methods. © 2004 Wiley‐Liss, Inc.
Emergence of long‐term memory for conditioned aversion in the rat fetus
Authors: Gruest Nadège , Richer Paulette , Hars Bernard
Published: March 2004

Pregnant rats were subjected to garlic essential oil as the conditioned stimulus and 45 min later to LiCl as the unconditioned stimulus either on embryonic Days 15 and 16 (E15 and E16) or on 18 and 19 (E18 and E19). Control dams received only garlic, LiCl, or water. Progenies were tested on garlic drinking 6 weeks after the exposure to the stimuli via the mothers. In the E18 to 19 group, rats that were exposed to paired garlic–LiCl expressed a significant aversion for garlic. In the E15 to 16 group, no significant differences appeared between subgroups. These results confirm that an associative memory can be established before birth and suggests that this ability potentially emerges in a short time window of 3 days at the end of gestation. Moreover, it appears that a long‐term memory can be acquired in utero and retained to be expressed postnatally when animals are autonomous. © 2004 Wiley Periodicals, Inc. Dev Psychobiol 44: 189–198, 2004.
Hyperinsulinemic hypoglycemia of infancy: the challenge continues
Authors: Dekelbab Bassem H. , Sperling Mark A.
Published: March 2004

Hypoglycemia due to hyperinsulinemia is the most common cause of persistent hypoglycemia in infants and children. Recent discoveries in the molecular and biochemical regulation of insulin secretion have dramatically increased our understanding of the disorders responsible for syndromes of hyperinsulinemic hypoglycemia. Here, we briefly review the current knowledge of disorders of the KATP channel, activating mutations of glucokinase and glutamate dehydrogenase (GDH) and other disorders that may be associated with specific phenotypes and permit appropriate targeted therapies. Despite these advances, much remains to be learned. We do not understand the mechanisms or defects in many instances, including defective carbohydrate glycosylation syndromes and perinatal hypoxia, both of which may be associated with hyperinsulinemia. Most importantly, preoperative distinction between diffuse and focal lesions cannot be always reliably made even after selective arterial infusion with calcium, glucose or a sulfonylurea with concurrent hepatic venous sampling for insulin. The ability to distinguish diffuse from localized lesions has profound implications for therapeutic approaches, prognosis and genetic counseling. To date, about 50% of individuals with hyperinsulinemic hypoglycemia of infancy can be correctly categorized. Thus, the challenge continues. Copyright © 2004 John Wiley & Sons, Ltd.
Peroxidase activity in the intestinal tract of Wistar–Furth, BBc and BBdp rats
Authors: Courtois Philippe , Sener Abdullah , Scott Fraser W. , Malaisse Willy J.
Published: March 2004

Background

The development of immune‐mediated diabetes in BB rats may involve an inflammatory lesion of the intestinal tract.

Methods

In order to further explore this issue, the activity of peroxidase was measured, in the absence and presence of either bromide or dapsone, at day 10, 30, 45, 70, 95 and 120 in three segments (top, mid and bottom) of the intestinal tract from Wistar–Furth rats and both diabetes‐resistant and diabetes‐prone BB rats fed after weaning either diabetes‐promoting diets or a protective diet, which decreases the incidence of diabetes in the BB rats.

Results

In the present study, from day 30 onwards, an age‐related increase in peroxidase activity was found in the intestine of diabetes‐prone BB rats (BBdp rats) fed diabetogenic diets, when compared with either Wistar–Furth or diabetes‐resistant BB rats (BBc rats). This increase was most pronounced in the distal segments of the intestinal tract. Even when fed a protective diet, higher peroxidase activity was found in BBdp than BBc rats. Yet, in BBc rats, and to a lesser extent in BBdp rats, the diabetogenic diets lowered peroxidase activity below the value found in rats of the same strain fed the protective diet. There was a tight correlation between the activity of peroxidase and its susceptibility to be increased by bromide.

Conclusion

It is proposed that diabetogenic diets may decrease peroxidase activity in intestinal cells, this effect becoming masked in BBdp rats by an age‐related increase in the contribution of inflammatory cells. The latter phenomenon affects preferentially the distal segments of the intestinal tract. Copyright © 2004 John Wiley & Sons, Ltd.
Linear Multinuclear RuII Photosensitizers
Authors: Vaduvescu Simona , Potvin Pierre G.
Published: March 2004

Four ditopic bridging ligands, containing 2,2′:6′,2′′‐terpyridine and 2,6‐dipyrazinylpyridine (dpp) metal‐binding units attached through p‐ or m‐phenylene linkages, have been incorporated into eight mono‐, di‐ and trinuclear linear RuII complexes. These were characterized by UV/Vis spectroscopy and cyclic voltammetry, and by their ability to undergo light‐induced electron transfers to methylviologen. The dpp‐bearing complexes were more difficult to prepare but were superior sensitizers, a fact attributable to longer excited state lifetimes and an electrostatically favored reductive quenching pathway. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Electrochemical Studies of Complexes with Oxo‐ or Hydroxo‐Bridged {Mo2(µ‐SMe)3}+ Centers: Cleavage of the Oxygen Bridge and Generation of Substrate‐Binding Sites
Authors: Le Hénanf Marc , Le Roy Christine , Muir Kenneth W. , Pétillon François Y. , Schollhammer Philippe , Talarmin Jean
Published: March 2004

The reduction of [Mo2(Cp)2(µ‐SMe)3(µ‐O)]+ (1+) has been investigated by cyclic voltammetry and controlled‐potential electrolysis in THF‐ and MeCN/NBu4PF6 without added acid or in the presence of various acids HX (HX: HTsO, CF3CO2H, HBF4). Reduction in the presence of acid follows an ECrevE mechanism in which the intermediate chemical step is an acid‐base equilibrium between 1 and [Mo2(Cp)2(µ‐SMe)3(µ‐OH)]+ (2+). This electrochemical process is followed by protonation of the neutral µ‐hydroxo complex 2 to afford different products which depend both on the solvent (THF or MeCN) and on the nature of the acid. Controlled‐potential electrolysis of 1+ in the presence of HX (2 equiv.) leads to the generation of binding sites and finally gives products identical to those obtained from protonation of 2 by HX. The complex [Mo2(Cp)2(µ‐SMe)3(µ‐η1,η1‐OCOCF3)] (3) which can be obtained either by protonation of 2 by CF3CO2H or by reduction of 1+ in the presence of CF3CO2H, has been characterized crystallographically. In the presence of HBF4 protonation of 1+ gives 22+. The reactivity of 2+ and of the complexes [Mo2(Cp)2(µ‐SMe)3(H2O)(TsO)] (4) and [Mo2(cp)2(µ‐SMe)3(H2O)L]+ (L = H2O or THF) (6+), all of which contain a terminal aqua ligand, has also been investigated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Catalysis at the Interface of Ruthenium Carbene and Ruthenium Hydride Chemistry: Organometallic Aspects and Applications to Organic Synthesis
Authors: Schmidt Bernd
Published: March 2004

Soon after the introduction of stable and defined ruthenium precatalysts for olefin metathesis it was discovered that double bond migrations may interfere with the metathesis reaction. This undesired side reaction has been attributed to the formation of ruthenium hydride species from metathesis‐active ruthenium carbene species in situ. Over the past few years, several studies have indeed revealed the existence of pathways leading from ruthenium carbene to ruthenium hydride complexes. Furthermore, a number of examples have been published recently where typical precatalysts for olefin metathesis were found to promote non‐metathesis transformations efficiently in preparatively useful yields and selectivities, presumably via the in situ formation of ruthenium hydride species. These results open up a pathway to the development of novel catalyzed reaction sequences that combine ruthenium carbene‐ and ruthenium‐hydride‐mediated steps. This paper provides an overview of the field and covers organometallic aspects as well as synthetic applications. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Solvation Effect of Li+ on the Voltammetric Properties of [PMo12O40]3−. Part 2: Comparative Studies on the Preferential Solvation in Acetonitrile+S and Acetone+S Mixtures
Authors: Himeno Sadayuki , Takamoto Masayo , Ueda Tadaharu , Santo Ryoko , Ichimura Akio
Published: March 2004

For [PMo12O40]3−, the presence of Li+ produced a two‐electron wave at nearly the same potential as the first one‐electron wave in acetonitrile or acetone. The voltammetric behavior of [PMo12O40]3− in a binary mixture of acetonitrile and solvent S was compared with those in a mixture of acetone and S. When the donor number (DN) of S>20, the first two‐electron wave was converted into one‐electron waves in such binary mixtures. The conversion occurred at lower mole fractions of S in an acetonitrile+S mixture than in an acetone+S mixture. The 7Li NMR results showed that the preferential solvating ability of Li+ with S was greater in the former mixture. A linear relationship was found between the iso‐solvation point xiso(S) and the reciprocal of the difference between the DNs of S and acetonitrile, which gave the basis to explain the anomalies observed for a mixture of acetonitrile and H2O.
Characterization of ABTS at a Polymer‐Modified Electrode
Authors: Thomas Jennifer H. , Drake J. Michael , Paddock Jean R. , Conklin Sean , Johnson Jay , Seliskar Carl J. , Halsall H. Brian , Heineman William R.
Published: March 2004

ABTS, 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonate), a colorless dianion that forms a colored radical upon oxidation, was characterized with electrochemistry and spectroscopy and demonstrated to be a detectable analyte in a polymer‐modified spectroelectrochemical sensor. Three positively charged polymers were incorporated into a thin film on an indium tin oxide (ITO) optically transparent electrode and used to concentrate ABTS at the electrode surface. Of the three films, poly(vinylbenzyl trimethyl ammonium chloride)‐poly(vinyl alcohol) (PVTAC‐PVA), poly(diallyldimethylammonium chloride)‐silica (PDMDAAC‐SiO2), and quaternized poly(4‐vinyl‐N‐methylpyridinium nitrate)‐silica (QPVP‐SiO2), PVTAC‐PVA demonstrated the best ability to absorb ABTS. Within 20 min, a change of 0.2 absorbance units at 417 nm and 13.6 μA/cm2 in anodic peak current density in cyclic voltammetry at a scan rate of 0.025 V/s were observed.
A Tubulin‐Based Quantitative Assay for Taxol (Paclitaxel) with Enzyme Channeling Sensing
Authors: Suye Shin‐ichiro , Nakamoto Daichi , Hori Teruo , Sugawara Fumio , Mulchandani Ashok
Published: March 2004

We report the development and characterization of a biosensor for sensitive and rapid determination of the anticancer agent Taxol (paclitaxel). The sensor is based on the interaction of Taxol with its receptor protein tubulin in conjunction with the separation‐free immunosensor technique of enzyme channeling. The sensor system consisted of a three electrode electrochemical cell containing a graphite carbon electrode modified with glucose oxidase and tubulin as working electrode poised at +40 mV (vs. Ag/AgCl). Addition of Taxol, horseradish peroxidase labeled Taxol, glucose and potassium iodide to the cell generated a cathodic current response that was proportional to the concentration of Taxol in the range of 10 to 1 000 pM.
Electroanalytical Determination of Zinc in Human Blood Facilitated by Acoustically Assisted Double Extraction
Authors: Kruusma Jaanus , Banks Craig E. , Lust Enn , Keis Heldur , Nei Lembit , Compton Richard G.
Published: March 2004

The electroanalytical determination of zinc in human blood via an acoustically assisted double extraction technique is reported. First zinc(II) is rapidly extracted from diluted blood via complexation with diphenylthiocarbazone in chloroform through acoustic emulsification of the two phases. After insonation the bulk phases reform and the metal is back extracted by emulsifying with electrochemically clean aqueous acid and the zinc quantified via anodic stripping voltammetry, giving close agreement to the blind independent AAS analysis. The double extraction method is effective since species that otherwise interfere with the direct ASV determination either remain in the initial aqueous phase, or are transferred to the organic phase, but are unlikely to be doubly transferred so producing a ‘clean’ final aqueous medium for ASV.
The Electrochemical Behavior and the Quantitative Determination of Nitrogen Dioxide at a Solid Polymer Electrolyte Supported Pt‐Au Electrode
Authors: Wang Kangli , Yan Heqing , Liu Jun , Sun Xiaoyan , Wang E'feng
Published: March 2004

The electrochemical behavior of NO2 at Au/Nafion, Pt/Nafion and Pt‐Au/Nafion electrodes was investigated by using electrochemical and SEM methods, respectively. It was found that the Pt‐Au/Nafion electrode showed higher electrocatalytic activity than Pt/Nafion and Au/Nafion electrodes. The net current density of Au/Nafion electrode decayed significantly during the reaction, though it showed high initial value. Pt/Nafion and Pt‐Au/Nafion electrodes, on the contrary, showed good stability. A quantitative determination of NO2 concentration was carried out at Pt‐Au/Nafion electrode and a satisfactory linear relationship was found for the NO2 concentration in the range of 0–100 ppm.
Ion‐Selective Electrodes for Thiocyanate Based on the Dinuclear Zinc(II) Complex of a Bis‐N,O‐bidentate Schiff Base
Authors: Bühlmann Philippe , Yahya Lisa , Enderes Rolly
Published: March 2004

An ion selective electrode based on the dinuclear complex formed by two zinc(II) ions and two molecules of the bis‐N,O‐bidentate Schiff base 2,2′‐[methylenebis(4,1‐phenylenenitrilomethylidyne)]bisphenol exhibits thiocyanate selectivity with a good discrimination of nitrite, nitrate, and azide. The selectivities of electrode membranes with various compositions indicate that this potentiometric selectivity is based on the formation of a 1 : 1 complex between the thiocyanate anion and the dinuclear ionophore. The 2 : 1 ratio of thiocyanate ions and the dinuclear ionophore that results from higher ratios of cationic sites and ionophore worsens the selectivity, suggesting that binding of a thiocyanate to both zinc(II) centers of the dinuclear ionophore is not favorable. Interestingly, the selectivity patterns of these electrodes differ radically from that of a highly sulfate selective electrode based on a compound reported previously to be the analogous mononuclear 1 : 1 complex of zinc(II) and the same Schiff base. It is suggested that the previously reported 1 : 1 complex with zinc(II) may indeed have been a polymer of the same elemental composition.
Development of an adaptive discontinuity‐capturing hyperbolic finite element model
Authors: Fang C. C. , Sheu Tony W. H.
Published: March 2004

In this paper we present a five‐parameter Taylor–Galerkin finite element model to simulate Euler equations in a domain of two dimensions. The introduced free parameters are theoretically determined by employing M‐matrix theory to obtain a physically correct and non‐oscillatory solution in regions containing a sharp solution profile. To improve the computational efficiency and solution accuracy, grids are adaptively added to obtain solutions with fewer mesh points. The discontinuity‐capturing finite element model has been validated against test cases, reproducing analytical solutions to the gas dynamic problems under the current investigation. Copyright © 2004 John Wiley & Sons, Ltd.
Interfacial dynamics‐based modelling of turbulent cavitating flows, Part‐1: Model development and steady‐state computations
Authors: Senocak Inanc , Shyy Wei
Published: March 2004

The merits of transport equation‐based models are investigated by adopting an enhanced pressure‐based method for turbulent cavitating flows. An analysis of the mass and normal‐momentum conservation at a liquid–vapour interface is conducted in the context of homogeneous equilibrium flow theory, resulting in a new interfacial dynamics‐based cavitation model. The model offers direct interpretation of the empirical parameters in the existing transport‐equation‐based models adopted in the literature. This and three existing cavitation models are evaluated for flows around an axisymmetric cylindrical body and a planar hydrofoil, and through a convergent–divergent nozzle. Although all models considered provide qualitatively comparable wall pressure distributions in agreement with the experimental data, quantitative differences are observed in the closure region of the cavity, due to different compressibility characteristics of each cavitation model. In particular, the baroclinic effect of the vorticity transport equation plays a noticeable role in the closure region of the cavity, and contributes to the highest level of turbulent kinetic energy there. Copyright © 2004 John Wiley & Sons, Ltd.
Column‐based model of electric field excitation of cerebral cortex
Authors: Fox Peter T. , Narayana Shalini , Tandon Nitin , Sandoval Hugo , Fox Sarabeth P. , Kochunov Peter , Lancaster Jack L.
Published: March 2004

A model to explain the orientation selectivity of the neurophysiologic effects of electric‐field transients applied to cerebral cortex is proposed and supported with neuroimaging evidence. Although it is well known that transcranial magnetic stimulation (TMS) excites cerebral cortex in an orientation‐selective manner, a neurophysiologically compelling explanation of this phenomenon has been lacking. It is generally presumed that TMS‐induced excitation is mediated by horizontal fibers in the cortical surfaces nearest to the stimulating coil, i.e., at the gyral crowns. No evidence exists, however, that horizontal fibers are orientation selective either anatomically or physiologically. We used positron emission tomography to demonstrate that TMS‐induced cortical activation is selectively sulcal. This observation allows the well‐established columnar organization of cerebral cortex to be invoked to explain the observed orientation selectivity. In addition, Rushton's cosine principle can used to model stimulation efficacy for an electrical field applied at any cortical site at any intensity and in any orientation. Hum. Brain Mapp. 22:1–16, 2004. © 2004 Wiley‐Liss, Inc.
Enhancement of GABA‐related signalling is associated with increase of functional connectivity in human cortex
Authors: Fingelkurts Andrew A. , Fingelkurts Alexander A. , Kivisaari Reetta , Pekkonen Eero , Ilmoniemi Risto J. , Kähkönen Seppo
Published: March 2004

Structural or operational synchrony analysis with EEG was conducted in order to detect functional interaction between cortical areas during an enhanced inhibition induced by the GABAergic agonist lorazepam in a double‐blind, randomized, placebo‐controlled, cross‐over study in eight healthy human subjects. Specifically, we investigated whether a neuronal inhibitory system in the brain mediates functional decoupling of cortical areas. Single‐dose lorazepam administration resulted in a widespread increase in the inter‐area functional connectivity and an increase in the strength of functional long‐range and interhemispheric connections. These results suggest that inhibition can be an efficient mechanism for synchronization of large neuronal populations. Hum. Brain Mapping 22:29–41, 2004. © 2004 Wiley‐Liss, Inc.
Scale‐free dynamics of global functional connectivity in the human brain
Authors: Stam Cornelis Jan , de Bruin Eveline Astrid
Published: March 2004

Higher brain functions depend upon the rapid creation and dissolution of ever changing synchronous cell assemblies. We examine the hypothesis that the dynamics of this process displays scale‐free, self‐similar properties. EEGs (19 channels, average reference, sample frequency 500 Hz) of 15 healthy subjects (10 men; mean age 22.5 years) were analyzed during eyes‐closed and eyes‐open no‐task conditions. Mean level of synchronization as a function of time was estimated with the synchronization likelihood for five frequency bands (0.5–4, 4–8, 8–13, 13–30, and 30–48 Hz). Scaling in these time series was investigated with detrended fluctuation analysis (DFA). DFA analysis of global synchronization time series showed scale‐free characteristics, suggesting neuronal dynamics do not necessarily have a characteristic time constant. The scaling exponent as determined with DFA differed significantly for different frequency bands and conditions. The exponent was close to 1.5 for low frequencies (δ, θ, and α) and close to 1 for β and γ bands. Eye opening decreased the exponent, in particular in α and β bands. Fluctuations of EEG synchronization in δ, θ, α, β, and γ bands exhibit scale‐free dynamics in eyes‐closed as well as eyes‐open no‐task states. The decrease in the scaling exponent following eye opening reflects a relative preponderance of rapid fluctuations with respect to slow changes in the mean synchronization level. The existence of scaling suggests that the underlying dynamics may display self‐organized criticality, possibly representing a near‐optimal state for information processing. Hum. Brain Mapping 22:99–111, 2004. © 2004 Wiley‐Liss, Inc.
Fetal brain activity and hemodynamic response to a vibroacoustic stimulus
Authors: Fulford Jonathan , Vadeyar Shantala H. , Dodampahala Sanani H. , Ong Stephen , Moore Rachel J. , Baker Philip N. , James David K. , Gowland Penny
Published: March 2004

Previous studies have demonstrated the practicality of using functional magnetic resonance imaging (fMRI) techniques to assess fetal brain activity. The purpose of this study was to compare the fetal hemodynamic response to that of the adult. Seventeen pregnant subjects, all of whom were at more than 36 weeks gestation were scanned while the fetus was exposed to a vibroacoustic stimulus. Thirteen adult subjects were scanned with an equivalent acoustic stimulus. Of the fetal subjects, two could not be analyzed due to technical problems, eight did not show significant activation, and seven showed significant activation. In all cases, activation was localized within the temporal region. Measures of fetal hemodynamic responses revealed an average time to peak (ttp) of 7.36 ± 0.94 sec and an average percentage change of 2.67 ± 0.93%. In contrast, activation was detected in 5 of 13 adults with an average ttp of 6.54 ± 0.54 sec and an average percentage change of 1.02 ± 0.40%. The measurement of changes in the fetal hemodynamic response may be important in assessing compromised pregnancies. Hum. Brain Mapping 22:118–123, 2004. © 2004 Wiley‐Liss, Inc.
Synthesis of 2,3‐dihydro‐1,3,4‐thiadiazole, thiazole, and triazolo[4,3‐a]pyrimidine derivatives from ethyl benzoylacetate
Authors: Rateb Nora M. , Abdelhamid Abdou O.
Published: March 2004

Thiophene and thiazole derivatives can be obtained from potassium salt of ethyl 3‐oxo‐3‐phenyl‐2‐[(phenylamino)thioxomethyl]propanoate and ethyl chloroacetate in N,N‐dimethylformamide solution under different conditions. 2,3‐Dihydro‐1,3,4‐thiadiazoles and triazolo[4,3‐a]pyrimidine were obtained from reaction of hydrazonoyl halides with each of thioanilide and pyrimidine‐2‐thione, respectively. Structures of the newly synthesized compounds were elucidated on the basis of elemental analysis, spectral data, and alternative synthesis route whenever possible. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:107–113, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10222
Synthesis and structural studies of N‐(p‐toluenesulfonyl)‐amino acid 3,5‐di‐tert‐butyl‐2‐phenolamides
Authors: Tlahuextl Margarita , Aguilar‐Castro Liliana , Camacho‐Camacho Carlos , Contreras Rosalinda , Tapia‐Benavides Antonio R.
Published: March 2004

This paper describes the synthesis and structural studies of N‐(p‐toluenesulfonyl)‐amino acid 3,5‐di‐tert‐butyl‐2‐phenolamides by 1H, 13C, and 15N. The presence of intra‐ and intermolecular hydrogen bonds were studied by variable temperature NMR spectroscopy. The molecular structure of two amides in the solid state was determined by X‐ray diffraction experiments. The results show that tert‐butyl substituents in the phenolic ring have important effects in the nature of hydrogen bonds and conformation of these amides. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:114–120, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10223
An improved procedure for phenylselenoetherification of some Δ5‐alkenols using pyridine, Ag2O, and some Lewis acids as catalysts
Authors: Bugarčić Zorica M. , Mojsilović Biljana M.
Published: March 2004

An improved procedure for intramolecular cyclization of some Δ5‐alkenols, using PhSeX (X = Cl, Br) has been developed. We found that cyclization can be facilitated in the presence of pyridine, Ag2O, and some Lewis acids as catalysts. Thus catalytic amount of additives (pyridine and Ag2O) influences higher yields but equimolar amount achieves almost quantitative yield under extremely mild experimental conditions. In the presence of Lewis acids (ZnCl2 and FeCl3) high yields of cyclic ether products are obtained with catalytic amounts. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:146–149, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10227
Methylation of some cyclic triphosphenium ions
Authors: Dillon Keith B. , Olivey Richard J.
Published: March 2004

Six cyclic triphosphenium ions, including examples of five‐, six‐, and seven‐membered ring systems, have been successfully methylated by excess methyl triflate to form the corresponding dications. This has been unequivocally established by means of 31P NMR spectroscopy; results are in good agreement with literature data for this type of compound. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:150–154, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10228
Reaction of an ammonium eneselenolate derived from a selenothioacetic acid S‐ester with electron‐deficient alkenes and alkynes
Authors: Murai Toshiaki , Kondo Taichi , Kato Shinzi
Published: March 2004

Ammonium eneselenolate 2 derived from selenothioic acid S‐ester 1 was reacted with electron‐deficient alkenes 4 and alkynes 9. Ammonium eneselenolate 2 underwent Michael addition with 4 to give two types of Michael adducts, 5 and 6. Products 6 incorporated two molecules of 4. In contrast, the reaction of 2 with 9 took place at the selenium atom to give γ‐oxo divinyl selenides 10 with high Z‐stereoselectivity. During the further elaboration of the reactivity of the products derived from 2 and carbonyl compounds, unexpected reaction was found in the addition of vinylmagnesium bromide to Se‐vinyl ester 3. The spectroscopic data supported the formation of the enol form 12 of β‐oxo selenothioic acid S‐ester 13. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:187–192, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20003
Novel conversion of 6H‐1,3,5‐oxathiazine S‐oxides into 5‐membered heterocyclic compounds
Authors: Rafiqul Islam Md. , Shimada Kazuaki , Aoyagi Shigenobu , Takikawa Yuji , Kabuto Chizuko
Published: March 2004

5H‐1,2,4‐oxathiazoles were efficiently synthesized from 6H‐1,3,5‐oxathiazine S‐oxides by thermal cycloreversion of the substrates and the products were effectively converted into 1,2,4‐thiadiazoles. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:175–186, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20004
The effect of a major cigarette price change on smoking behavior in california: a zero‐inflated negative binomial model
Authors: Sheu Mei‐ling , Hu Teh‐wei , Keeler Theodore E. , Ong Michael , Sung Hai‐Yen
Published: March 2004

The objective of this paper is to determine the price sensitivity of smokers in their consumption of cigarettes, using evidence from a major increase in California cigarette prices due to Proposition 10 and the Tobacco Settlement.

The study sample consists of individual survey data from Behavioral Risk Factor Survey (BRFS) and price data from the Bureau of Labor Statistics between 1996 and 1999. A zero‐inflated negative binomial (ZINB) regression model was applied for the statistical analysis.

The statistical model showed that price did not have an effect on reducing the estimated prevalence of smoking. However, it indicated that among smokers the price elasticity was at the level of −0.46 and statistically significant.

Since smoking prevalence is significantly lower than it was a decade ago, price increases are becoming less effective as an inducement for hard‐core smokers to quit, although they may respond by decreasing consumption. For those who only smoke occasionally (many of them being young adults) price increases alone may not be an effective inducement to quit smoking. Additional underlying behavioral factors need to be identified so that more effective anti‐smoking strategies can be developed. Copyright © 2004 John Wiley & Sons, Ltd.