bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel two‐color fluorescence probe with extreme specificity to bovine serum albumin
Authors: Ercelen Sebnem , Klymchenko Andrey S. , Demchenko Alexander P.
Published: March 2003

We report on strong, highly specific and stochiometric binding to bovine serum albumin of novel fluorescence probe FA, 2‐(6‐diethylaminobenzo[b]furan‐2‐yl)‐3‐hydroxychromone, that exhibits a very characteristic two‐band fluorescence spectrum. Both absorption band and two fluorescence bands of FA are very sensitive to non‐covalent interactions in the immediate environment of the probe. Multiparametric analysis of this spectroscopic information allows us to conclude that the binding site is characterized by very low polarity, high extent of screening from aqueous environment and unusually high electronic polarizability. The latter suggests the proximal location of probe FA to the aromatic amino acid residues in the binding site. The new probe can be proposed for the study of interaction of ligands and drugs of different nature with serum albumins.
A hydrophobic platform as a mechanistically relevant transition state stabilising factor appears to be present in the active centre of all glycoside hydrolases
Authors: Nerinckx W. , Desmet T. , Claeyssens M.
Published: March 2003

An in silico survey of the −1 subsite of all known 3D‐structures of O‐glycoside hydrolases containing a suitably positioned ligand has led to the recognition – apparently without exceptions – of a transition state stabilising hydrophobic platform which is complementary to a crucial hydrophobic patch of the ligand. This platform is family‐specific and highly conserved. A comprehensive list is given with examples of enzymes belonging to 33 different families. Several typical constellations of platform – protein residues are described.
A novel protein phosphatase 2C family member (PP2Cζ) is able to associate with ubiquitin conjugating enzyme 91
Authors: Kashiwaba Mitsuhiro , Katsura Koji , Ohnishi Motoko , Sasaki Mutsuo , Tanaka Hiromitsu , Nishimune Yoshitake , Kobayashi Takayasu , Tamura Shinri
Published: March 2003

In this study we have cloned a novel member of mouse protein phosphatase 2C family, PP2Cζ, which is composed of 507 amino acids and has a unique N‐terminal region. The overall similarity of the amino acid sequence between PP2Cζ and PP2Cα was 22%. On Northern blot analysis PP2Cζ was found to be expressed specifically in the testicular germ cells. PP2Cζ expressed in COS7 cells was able to associate with ubiquitin conjugating enzyme 9 (UBC9) and the association was enhanced by co‐expression of small ubiquitin‐related modifier‐1 (SUMO‐1), suggesting that PP2Cζ exhibits its specific role through its SUMO‐induced recruitment to UBC9.
HECKSCHER–OHLIN THEORY: HAS IT A FUTURE?
Authors: KEMP MURRAY C.
Published: March 2003

It is noted that Heckscher-Ohlin general-equilibrium theory is based on three little discussed assumptions (representative agents, costless reallocation of productive factors, and the existence of autarkic equilibria) and it is argued that the theory is highly sensitive to the relaxation of any one of the assumptions.
Silicic Acid Polymerization Catalyzed by Amines and Polyamines
Authors: Mizutani Tadashi , Nagase Hisato , Ogoshi Hisanobu
Published: March 2003

Polymerization and subsequent gelation of silicic acid in water were catalyzed by amines and polyamines. Particularly effective were poly(allylamine), poly(lysine), and poly(arginine), which promoted spontaneous gelation. The resultant silica gel contained a sizable portion of amines, which altered the surface properties of silica gel.
Total Synthesis of Antibiotic, Micrococcin P, from 2,3,6-Polythiazolesubstituted Pyridine Skeleton [Fragment A-C]
Authors: Shin Chung-gi , Okumura Kazuo , Shigekuni Masashi , Nakamura Yutaka
Published: March 2003

Total synthesis of an antibiotic, micrococcin P, was first accomplished by the coupling of a 2,3,6-polythiazole-substituted pyridine skeleton [Fragment A-C] with the independently synthesized Fragments B and D, and then deprotection with trifluoroacetic acid and final intramolecular cyclization using BOP as condensing agent.
Synthesis of a Photoaffinity-labeling Analog of Alternariolide (AM-toxin I), a Host-specific Phytotoxin
Authors: Hashimoto Kimiko , Yoshioka Takuya , Morita Chikanori , Sakai Mitsuru , Okuno Toshikatsu , Shirahama Haruhisa
Published: March 2003

A photoaffinity-labeling analog of alternariolide (AM-toxin I) which contains L-2-amino-5-[4-(1-azi-2,2,2-trifluoro)ethylphenyl]pentanoic acid (10) was synthesized.
Chiral Nematic Glasses from Novel Hydrogen-Bonded Mesogens
Authors: Mallia V Ajay , Antharjanam P K Sudhadevi , Das Suresh
Published: March 2003

A novel class of liquid crystals capable of forming chiral nematic glasses has been obtained via intermolecular hydrogen bonding between cholesterol linked azopyridyl derivatives and substituted aromatic acids.
Chemical Modification of Curdlan to Induce an Interaction with Poly(C)
Authors: Koumoto Kazuya , Kimura Taro , Kobayashi Hideki , Sakurai Kazuo , Shinkai Seiji
Published: March 2003

The molecular weight of the commercially available curdlan is over 106, which makes it difficult to bind to polynucleotides. This paper presents a chain-scission reaction of curdlan and the molecular weight dependence of the binding ability. We found that curdlan can bind to poly(C) when the molecular weight is less than about 105. However, the complex stability is still less than that of the single chain of schizophyllan.
Causes of electrical deaths and injuries among construction workers
Authors: McCann Michael , Hunting Katherine L. , Murawski Judith , Chowdhury Risana , Welch Laura
Published: March 2003

Background

Contact with electrical current is the fourth leading cause of deaths of construction workers. This study evaluates electrical deaths and injuries to construction workers.

Methods

Two sources of data were analyzed in detail: (1) 1,019 electrical deaths identified by the Bureau of Labor Statistics, Census of Fatal Occupational Injuries (CFOI) for the years 1992–1998; and (2) 61 electrical injuries identified between November 1, 1990 and December 31, 1998 from a George Washington University Emergency Department injury surveillance database.

Results

Contact with “live” electrical wiring, equipment, and light fixtures was the main cause of electrical deaths and injuries among electrical workers, followed by contact with overhead power lines. Among non‐electrical workers, contact with overhead power lines was the major cause of death. Other causes included contact with energized metal objects, machinery, power tools, and portable lights. Arc flash or blast caused 31% of electrical injuries among construction workers, but less than 2% of electrical deaths.

Conclusion

Adoption of a lockout/tagout standard for construction, and training for non‐electrical workers in basic electrical safety would reduce the risk of electrical deaths and injuries in construction. Further research is needed on ways to prevent electrical deaths and injuries while working “live”. Am. J. Ind. Med. 43:398–406, 2003. © 2003 Wiley‐Liss, Inc.
Apricot sulfurization: An occupation that induces an asthma‐like syndrome in agricultural environments
Authors: Koksal Nurhan , Hasanoglu Hatice Canan , Gokirmak Munire , Yildirim Zeki , Gultek Ahmet
Published: March 2003

Background

Several cases of bronchial asthma have been presenting with acute attacks during the seasons of apricot sulfurization. The aim of this study was to reveal the effects of sulfur dioxide (SO2) exposure on the airways of the workers involved in this process.

Methods

SO2 levels in air were measured on 15 apricot farms, while the symptom scores of 69 workers were recorded before, during, and after SO2 exposure. Physical examination and pulmonary function tests (PFT) of the workers were also done prior to and after exposure periods.

Results

The measured SO2 concentrations ranged between 106.6 and 721.0 ppm. Dyspnea (80%), cough (78%), and eye and nose irritation (83–70%) were the most commonly observed symptoms. The workers had significant decreases in pulmonary functions after SO2 exposure. Decrements in FEV1, FEV1/FVC%, and FEF25–75% showed that the acute effect of SO2 on pulmonary functions of the workers was mostly of obstructive pattern.

Conclusions

Acute exposure to SO2 induces “asthma‐like syndrome” (ALS) in apricot sulfurization workers. SO2 which has not been previously reported in agricultural environments as a cause of ALS may be considered as a new agent. Am. J. Ind. Med. 43:447–453, 2003. © 2003 Wiley‐Liss, Inc.
Cover Picture: Multisite Catalysis: A Mechanistic Study of β‐Lactone Synthesis from Epoxides and CO—Insights into a Difficult Case of Homogeneous Catalysis (Chem. Eur. J. 6/2003)
Authors: Molnar Ferenc , Luinstra Gerrit A. , Allmendinger Markus , Rieger Bernhard
Published: March 2003

The cover picture shows the molecular structure of the complex formed by Al(O‐iPr)3 (acts as Lewis acid), β‐propiolactone, and the [Co(CO)4]− anion (aluminium: pink; carbon: grey; cobalt: blue; hydrogen: white; oxygen: red). This structure corresponds to the product complex in the formation of β‐lactones from epoxides and carbon monoxide (schematically shown in the upper right hand corner). Carbonylation of epoxides by using a combination of Lewis acids and cobalt carbonyls was studied both by theoretical and experimental methods. Only the concerted interaction of a Lewis acid and a nucleophile (multisite catalysis) opens a low‐energy pathway for trans opening of oxirane rings. For more details see the article by F. Molnar, B. Rieger et al. on p. 1273 ff.
Intramolecular Opening of β‐Lactams with Amines as a Strategy Toward Enzymatically or Photochemically Triggered Activation of Lactenediyne Prodrugs
Authors: Banfi Luca , Guanti Giuseppe , Rasparini Marcello
Published: March 2003

In order to develop a general strategy for selective activation of designed enediyne prodrugs belonging to the “lactenediyne” family, we studied the scope of intramolecular transamidation of simple monocyclic β‐lactams bearing a tethered amine. The effect of substituents, of reaction media, and of the type of tether, on the rate of transamidation is disclosed. The possibility of triggering the transamidation event under mild conditions by the action of suitable enzymes or UV light was demonstrated on model monocyclic β‐lactams. Finally, the strategy of intramolecular opening of the β‐lactam leading to a larger seven‐membered ring was employed on a lactenediyne, demonstrating that ring enlargement could unleash the reactivity of the enediyne moiety. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Immunohistochemical localization of S100‐like protein in non‐mammalian kidney
Authors: De Girolamo Paolo , Arcamone Nadia , Pelagalli Gaetano Vincenzo , Gargiulo Giuliana
Published: March 2003

The immunolocalization of S100‐like protein was investigated in the kidney of saltwater fishes (Dicentrarchus labrax; Coris julis; Serranus cabrilla; Scorpaena porcus), amphibia (Rana aesculenta), reptiles (Lacerta viridis), and aves (Gallus domesticus; Strutio camelus). S100‐like immunoreactivity was detected in the juxtaglomerular cells of all saltwater fishes studied. No immunoreactivity was observed in other tracts of the nephron or in the interstitial tissue. In frog kidney, S100‐like immunoreactive cells were localized in the proximal tubule, singly distributed or placed side by side in clusters of two or three cells. S100‐like immunoreactive cells were distributed in the distal and in the collecting tubules in lizard, chicken, and ostrich kidney. In the distal tubule of lizard kidney, S100‐like immunoreactive cells were numerous and uniformly distributed. In lizard collecting tubules, S100‐like immunoreactive cells showed less intense immunoreactivity than in the distal tubule, except for a cluster of cells at the junction with the initial collecting duct. In chicken and ostrich kidney, S100‐like immunoreactive cells of the distal tubules were closely packed together. In the collecting tubules, S100‐like immunoreactive cells were alternate to negative cells. These results indicate the high conservation degree of S100 proteins through phylogenesis and suggest a functional role for these proteins in the vertebrate kidney. Microsc. Res. Tech. 60:652–657, 2003. © 2003 Wiley‐Liss, Inc.
Mass spectrometric studies of 2‐aryl‐5‐acetylthiazole derivatives
Authors: Giorgi Gianluca , Salvini Laura , Attanasi Orazio A. , Guidi Barbara , Santeusanio Stefania
Published: March 2003

Electron ionisation mass spectrometry was usefully used to characterize structurally 2‐aryl‐5‐acetylthiazole derivatives in the gas phase. The compounds show characteristic fragmentation pathways depending on the chemical nature of the substituent at position 2, consisting mainly in the cleavage of both the 1,2‐ and 3,4‐bonds of the thiazole ring. Liquid secondary ion mass spectrometry was applied to study the effects of protonation on the gas‐phase unimolecular reactions of this class of compound. Tandem mass spectrometric experiments, carried out on molecular and protonated molecular ions, and also on fragment ions produced in the source, allowed the elucidation of gas‐phase decompositions of low‐internal energy ions. Copyright © 2001 John Wiley & Sons, Ltd.
Preparation of Poly(1,3,4‐oxadiazole‐2,5‐diyl‐1,2‐vinylene) via Anionic Mechanism
Authors: Zhang Ruifeng , Jordan Rainer , Nuyken Oskar
Published: March 2003

2,5‐Bis(chloromethyl)‐1,3,4‐oxadiazole was synthesized and dehydrohalogenation of this model compound was investigated under various base conditions. The formation of an intermediate with quinodimethane‐type structure is suggested for reaction in EtONa/EtOH. Polymerization of this intermediate proceeds via an anionic mechanism to form poly(1,3,4‐oxadiazole‐2,5‐diyl‐1,2‐vinylene). Polymerization at a toluene/water interface results in shorter polymerization times, milder conditions, higher molecular weights, higher yields and fewer defects in the polymer as compared to the corresponding polycondensation route.

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Lp error estimates and superconvergence for covolume or finite volume element methods
Authors: Chou So‐Hsiang , Kwak Do Y. , Li Qian
Published: March 2003

We consider convergence of the covolume or finite volume element solution to linear elliptic and parabolic problems. Error estimates and superconvergence results in the Lp norm, 2 ≤ p ≤ ∞, are derived. We also show second‐order convergence in the Lp norm between the covolume and the corresponding finite element solutions and between their gradients. The main tools used in this article are an extension of the “supercloseness” results in Chou and Li [Math Comp 69(229) (2000), 103–120] to the Lp based spaces, duality arguments, and the discrete Green's function method. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 19: 463–486, 2003
Low affinity cholecystokinin receptor inhibits cholecystokinin‐ and bombesin‐induced oscillations of cytosolic Ca2+ concentration
Authors: Lee Kwang Kook , Uhm Dae-Yong , Park Myoung Kyu
Published: March 2003

We have investigated whether low affinity cholecystokinin (CCK) receptors suppress agonist‐induced rises of cytosolic free Ca2+ concentration ([Ca2+]c) in pancreatic acinar cells by using properties of caffeine. A high concentration of caffeine (20 mM) completely blocked inositol 1,4,5‐trisphosphate (InsP3)‐induced [Ca2+]c rises but spared the InsP3‐independent long‐lasting [Ca2+]c oscillations. In the presence of 20 mM caffeine, only high concentrations of CCK, but not bombesin or JMV‐180, suppressed the caffeine‐resistant CCK or bombesin‐induced [Ca2+]c oscillations, indicating that low affinity CCK receptors inhibit agonist‐induced [Ca2+]c oscillations. It could be one of the underlying mechanisms by which low affinity CCK receptors suppress secretion in pancreatic acinar cells.
Crouching Dragon, Hungry Tigers: China and Central Asia
Authors: Spechler Martin C.
Published: March 2003

As their transition to market economies continue, China and the post‐Soviet republics of Central Asia have rediscovered their complementary economic and political interests in increasing trade and investments, especially between Xinjiang Province and independent Uzbekistan, the Kyrgyz Republic, and Kazakhstan. However, a number of obstacles remain, including payments arrangements, customs procedures, and transportation facilities. Prospects for trade in oil and gas, consumer goods, and agricultural materials are bright in the long run, however.
A p50-like Y-box protein with a putative translational role becomes associated with pre-mRNA concomitant with transcription
Authors: Soop Teresa , Nashchekin Dmitri , Zhao Jian , Sun Xin , Alzhanova-Ericsson Alla T. , Björkroth Birgitta , Ovchinnikov Lev , Daneholt Bertil
Published: March 2003

In vertebrates free messenger ribonucleoprotein (RNP) particles and polysomes contain an abundant Y-box protein called p50 (YB-1), which regulates translation, presumably by affecting the packaging of the RNA. Here, we have identified a p50-like protein in the dipteran Chironomus tentans and studied its relation with the biogenesis of mRNA in larval salivary glands. The salivary gland cells contain polytene chromosomes with the transcriptionally active regions blown up as puffs. A few giant puffs, called Balbiani rings (BRs), generate a transcription product, a large RNP particle,which can be visualised (with the electron microscope) during its assembly on the gene and during its transport to and through the nuclear pores. The p50-like protein studied, designated Ct-p40/50 (or p40/50 for short), was shown to contain a central cold-shock domain, an alanine- and proline-rich N-terminal domain, and a C-terminal domain with alternating acidic and basic regions, an organisation that is characteristic of p50 (YB-1). The p40/50 protein appears in two isoforms, p40 and p50, which contain 264 and 317 amino acids, respectively. The two isoforms share the first 258 amino acids and thus differ in amino-acid sequence only in the region close to the C-terminus. When a polyclonal antibody was raised against p40/50, western blot analysis and immunocytology showed that p40/50 is not only abundant in the cytoplasm but is also present in the nucleus. Immunolabelling of isolated polytene chromosomes showed that p40/50 appears in transcriptionally active regions, including the BRs. Using immunoelectron microscopy we revealed that p40/50 is added along the nascent transcripts and is also present in the released BR RNP particles in the nucleoplasm. Finally, by UV crosslinking in vivo we showed that p40/50 is bound to both nuclear and cytoplasmic poly(A) RNA. We conclude that p40/50 is being added cotranscriptionally along the growing BR pre-mRNA, is released with the processed mRNA into the nucleoplasm and probably remains associated with the mRNA both during nucleocytoplasmic transport and protein synthesis. Given that the p40/p50 protein, presumably with a role in translation, is loaded onto the primary transcript concomitant with transcription, an early programming of the cytoplasmic fate of mRNA is indicated.
Evidence that Ca2+ cycling by the plasma membrane Ca2+-ATPase increases the `excitability' of the extracellular Ca2+-sensing receptor
Authors: De Luisi Annunziata , Hofer Aldebaran M.
Published: March 2003

The extracellular Ca2+-sensing receptor (CaR) is a widely expressed G-protein-coupled receptor that translates information about[Ca2+] in the extracellular milieu to the interior of the cell,usually via intracellular Ca2+ signaling pathways. Using fura-2 imaging of cytoplasmic [Ca2+], we observed that HEK293 cells expressing CaR oscillated readily under conditions permissive for CaR activation. Spiking was also triggered in the absence of external Ca2+ by the CaR agonist spermine (1 mM). Oscillating cells were typically located in clusters of closely apposed cells, but Ca2+spiking was insensitive to the gap junction inhibitor 18α-glycyrrhetinic acid. We hypothesized that Ca2+ signals might be amplified, in part, through a positive feedback loop in which Ca2+ extrusion via the plasma membrane Ca2+-ATPase (PMCA) activates CaRs on the same cell or adjacent cells through local increases in[Ca2+]out. In support of this idea, addition of exogenous Ca2+ buffers (keeping free[Ca2+]out constant) attenuated or eliminated Ca2+ signals (manifested as oscillations), as did PMCA inhibitors(HgCl2, orthovanadate and Caloxin 2A1). Measurement of extracellular [Ca2+] using the near membrane probe fura-C18 revealed that external [Ca2+] rose following receptor activation, sometimes displaying an oscillatory pattern. Our data suggest that PMCA-mediated cycling of Ca2+ across the plasma membrane leads to localized increases in [Ca2+]out that increase the excitability of CaR.
Self-Formation and Anisotropic Electrical Conduction of Polypyrrole-Microtubes
Authors: Yan Hu , Ishida Tomoko , Toshima Naoki
Published: March 2003

Spontaneous appearance of polypyrrole microtubes was first observed during the electrochemical polymerization of pyrrole in water using sodium p-toluenesulfonate as a supporting salt. Almost amorphous microtube showed high electrical conductivity (σ = 498 S cm−1) along an axis of the tube. The tube also revealed extremely high anisotropy in the electrical conductivity. The ratios of the conductivity parallel to the axis (σ) to that perpendicular to the axis in plane (σ′) and to that across the plane (σ″) are as high as 103 (σ/σ′) and 105 (σ/σ″), respectively.
Oxazolylfulgides as Yellow Photochromic Dyes
Authors: Matsushima Ryoka , Morikane Hiroyuki , Kohno Yoshiumi
Published: March 2003

A series of substituted oxazolylfulgides have been prepared as photochromic compounds which color in the yellow region on irradiation with UV light. Some of them exhibit favorable features as photochromic yellow dyes in polymer film with fairly good photochemical reversibility, coloration quantum yields, and thermal stability.
Enantioselective Aziridination and Amination Using p-Toluenesulfonyl Azide in the Presence of Ru(salen)(CO) Complex
Authors: Omura Kazufumi , Murakami Masakazu , Uchida Tatsuya , Irie Ryo , Katsuki Tsutomu
Published: March 2003

(R,R)-Ru(salen)(CO) complex (1) was found to catalyze enantioselective aziridination of conjugated terminal olefins and allylic C–H amination of conjugated olefins bearing geminal- and/or trans-substituent(s) in the presence of p-toluenesulfonyl azide.
Progression of dopaminergic hypofunction in striatal subregions in Parkinson's disease using [18F]CFT PET
Authors: Nurmi Elina , Bergman Jörgen , Eskola Olli , Solin Olof , Vahlberg Tero , Sonninen Pirkko , Rinne Juha O.
Published: March 2003

The aim of this study was to investigate the progression of dopaminergic hypofunction in striatal subregions in Parkinson's disease (PD). We studied 12 patients with early PD and 11 healthy controls with a dopamine transporter ligand 2β‐carbomethoxy‐3β‐(4‐[18F]‐fluorophenyl)tropane ([18F]CFT) positron emission tomography (PET). The PET scan was carried out twice with an average interval of 2.2 years. The regions of interest (anterior and posterior putamen, caudate nucleus, and cerebellum) were drawn on individual magnetic resonance imaging (MRI) images, matched with the PET images, and copied onto the PET images. At the first PET scan in PD patients, the [18F]CFT uptake in the anterior putamen was 1.92 ± 0.67, which was 45% of the control mean, and in the posterior putamen 1.02 ± 0.55, being only 27% of the control mean. For the caudate nucleus the corresponding figure was 2.55 ± 0.58 (71% of the control mean). The uptake ratios had declined significantly by the time of the second PET scan and the absolute annual rate of decline of the tracer uptake was 0.23 ± 0.14 (P < 0.001) in the anterior putamen, 0.13 ± 0.13 (P = 0.005) in the posterior putamen, and 0.20 ± 0.15 (P < 0.001) in the caudate nucleus. There was a statistically significant difference of the decline in the tracer uptake between the anterior and posterior putamen (P = 0.033). When the rate of progression was calculated compared to the normal control mean, the rate of annual decline was 5.3% in the anterior putamen, 3.3% in the posterior putamen, and 5.6% in the caudate nucleus, without significant changes among striatal subregions (P = 0.10). When ipsi‐ and contralateral sides were analyzed separately, the absolute decline of [18F]CFT uptake in the putamen was higher in the side ipsilateral to the predominant symptoms than in the contralateral side (P = 0.035 for anterior putamen and P = 0.026 for posterior putamen). In the caudate nucleus the absolute decline was not different between ipsi‐ and contralateral sides (P = 0.76). In healthy controls, no significant decline of [18F]CFT uptake was detected. The results are suggestive of slower progression in the posterior putamen, where the disease is more advanced, but studies to follow up the same patient at several time points are needed to resolve this question. Synapse 48:109–115, 2003. © 2003 Wiley‐Liss, Inc.
MORPHOLOGICAL TEXTURE ANALYSIS USING THE TEXTURE EVOLUTION FUNCTION
Authors: McKENZIE J. , MARSHALL S. , GRAY A. J. , DOUGHERTY E. R.
Published: March 2003

This paper develops a new technique for modeling and classifying a growing texture using its evolution function over time. It encompasses morphological texture classification and parameter estimation with the objective of assessing the state of growth achieved by the texture using only a small sample set to train on, consistent with many real world situations for quality control. It is assumed that the texture model evolves over time according to the way in which its evolution function determines the parameters of its defining random process. This paper considers the random Boolean model for both binary and gray-scale images. A multiple linear regression model is used to estimate the Boolean model parameters as functions of the granulometric moments of the textures. Once the texture-model parameters are estimated, the time of the process can be found via the manner in which the parameters are determined by the dynamic evolutionary model.
ON SPECIAL RADICALS COINCIDING ON SIMPLE RINGS AND ON POLYNOMIAL RINGS
Authors: TUMURBAT S.
Published: March 2003

Answering a problem of M. Ferrero, we construct a special radical δ such that δ is contained in the Jacobson radical J, δ and J coincides on simple rings and on polynomial rings, but δ ≠ J. For two special radicals with the above conditions, we give a criterion of their coincidence.
Synthesis and Structural Characterization of the New Dioxygen Complexes of Molybdenum (IV)
Authors: Zhou Da-Yang , Zhang Li-Bin , Minato Makoto , Ito Takashi , Osakada Kohtaro
Published: March 2003

The molybdenum trihydrido complexes, [MoH3{[Ph2PCH2CH2P(Ph)C6H4-o]2(Ar)Si-P,P,P,P,Si}], which were readily formed by the thermal reaction of [MoH4(Ph2PCH2CH2PPh2)2] with arylsilanes, reacted with molecular dioxygen to give the unprecedented molybdenum(IV) peroxo type η2-O2 complexes, [MoH{[Ph2PCH2CH2P(Ph)C6H4-o]2(Ar)Si-P,P,P,P,Si)}(η2-O2)], the structure of which were studied spectroscopically as well as X-ray crystallographically.
Measurement of External Reflection Spectra of Protonated Tetraphenylporphyrin Adsorbed at Liquid-Liquid Interface
Authors: Moriya Yoshio , Ogawa Nobuaki , Kumabe Tomokazu , Watarai Hitoshi
Published: March 2003

External reflection UV-vis spectra of the interfacially adsorbed species of protonated tetraphenylporphyrin at toluene/aqueous sulfuric acid interface were successfully observed with clear negative absorption bands and without overlapping by the spectrum of the organic phase.
Simultaneous Control of Regio- and Stereochemistries in the Reaction between α-Alkoxyaldehydes and Pentadienyltin. Selective Preparations of the Four Regio- and Diastereoisomers
Authors: Nishigaichi Yutaka , Hanano Yasushi , Takuwa Akio
Published: March 2003

In the reaction between α-alkoxyaldehydes and pentadienyltin. each of the possible four regio- and stereoisomers, syn-γ-, anti-γ-, syn-ε-, and anti-ε-adducts, was selectively synthesized by the use of an appropriate combination of alkoxyl groups, Lewis acids, and solvents applied.
Controlled Association of Hydrophobized Polysaccharide by Cyclodextrin
Authors: Akiyoshi Kazunari , Sasaki Yoshihiro , Kuroda Kenichi , Sunamoto Junzo
Published: March 2003

The self-aggregate of cholesterol-bearing pullulan (CHP) dissociated by complexation with β-cyclodextrin (β-CD) to yield a dis-aggregated CHP-CD complex, in which the cholesteryl group was a suitable guest to β-CD. The monodisperse nanoparticles of the CHP self-aggregate were regenerated by addition of 1-adamantancarboxylic acid (ADC), which is the better guest molecule to β-CD than cholesterol. CD regulated the association and dissociation of hydrophobized polysaccharides in water.
Optimization of Sc3+ Ion Conduction in NASICON Type Solid Electrolytes
Authors: Tamura Shinji , Imanaka Nobuhito , Adachi Gin-ya
Published: March 2003

Various types of trivalent Sc3+ cation conducting solid electrolytes of the (Sc1−xAlx)1/3Zr2(PO4)3 (0≤x≤0.6), the Sc1/3(Zr1−yHfy)2(PO4)3 (0≤y≤1) and the (Sc0.8Y0.2)1/3Zr2(PO4)3 solid solutions were prepared and the Sc3+ ion conducting properties were compared. The optimum Sc3+ ion conductivity in NASICON type solid electrolytes was successfully obtained for the (Sc0.8Al0.2)1/3Zr2(PO4)3 and the Sc1/3(Zr0.8Hf0.2)2(PO4)3 solids, holding almost the equivalent NASICON crystal lattice size, and the optimization of the Sc3+ ion conduction in NASICON structure was realized.
Solvent Extraction of Some Metal Ions with Lipophilic Chitosan Chemically Modified with Functional Groups of Dithiocarbamate
Authors: Inoue Katsutoshi , Yoshizuka Kazuharu , Ohto Keisuke , Nakagawa Hirofumi
Published: March 2003

O,O′-Didecanoylchitosan chemically modified with functional groups of dithiocarbamate was prepared. The extent of the immobilization of the functional groups onto unit glucosamine unit of chitosan was 96%. It was soluble not only in chloroform and toluene but also in hexane and kerosene. Its solvent extraction behaviors for some base metal ions were examined. The order of the selectivity to these metal ions was found to be as follows: Cu(II)>>Ni(II)>>Fe(III)>Co(II)>Zn(II). The high selectivity to copper and nickel over iron is noteworthy.
New Metallocene Catalyst Having an Indenyl Group and a Fluorenyl Group for Ethylene–Polar Monomer Copolymerization
Authors: Imuta Jun-ichi , Toda Yoshihisa , Kashiwa Norio
Published: March 2003

New stereorigid bridged zirconocene having an indenyl group and a fluorenyl group as ligand was synthesized and investigated as an ethylene/1-hydroxy-10-undecene copolymerization catalyst. This catalyst using MAO as a cocatalyst promoted polymerization to produce copolymers having high molecular weight (Mw:121000) and high polar monomer content (36.7 mol%), displaying higher polymerization activities at higher temperature.
Reaction of 3,4-Di-t-butylthiophene 1-Oxide with 2-Methylene-1,3-dimethylimidazolidine: Methylene Transfer and [4+4] Dimerization
Authors: Nakayama Juzo , Takayama Jun , Sugihara Yoshiaki , Ishii Akihiko
Published: March 2003

The reaction of 3,4-di-t-butylthiophene 1-oxide (1) with 2-methylene-1,3-dimethylimidazolidine (2) gave 4,4a-di(t-butyl)-1a,4a-dihydro-1H-cyclopropa[b]thiophene and 1,3-dimethyl-2-imidazolidinone through a methylene transfer from 2 to 1, in addition to a [4+4] cyclodimerization product of 1.
Catalytic Oxidation of Various Alcohols to the Corresponding Carbonyl Compounds with N-Chlorosuccinimide Using a Catalytic Amount of Sulfenamide
Authors: Mukaiyama Teruaki , Matsuo Jun-ichi , Iida Daisuke , Kitagawa Hideo
Published: March 2003

Various primary and secondary alcohols were smoothly oxidized to the corresponding carbonyl compounds with N-chlorosuccinimide by using a catalytic amount of N-tert-butylbenzenesulfenamide (1) in the co-existence of potassium carbonate and molecular sieves 4A.
Study of Initial Adsorption Process of Hemoglobin to Glass Surface by Using Time-Resolved Slab Optical Waveguide(SOWG) Spectroscopy
Authors: Yoshida Takamitsu , Asano Hajime , Santos Jose H , Qi Zhi-Mei , Sun Li-Xian , Takatsu Akiko , Kato Kenji , Matsuda Naoki
Published: March 2003

A slab optical waveguide(SOWG) has been used to study the initial adsorption process of hemoglobin on glass surface using time-resolved absorption measurement of the evanescent wave. Absorbance data were taken at 50-ms time interval during the first 12 s after the measurement has started. Results showed that hemoglobin was adsorbed on glass and the data demonstrated excellent agreement with Langmuir-like model.
Preparation of Various Carboxylic Acid Esters from Bulky Alcohols and Carboxylic Acids by a New Type Oxidation-reduction Condensation Using 2,6-Dimethyl-1,4-benzoquinone
Authors: Mukaiyama Teruaki , Kikuchi Wataru , Shintou Taichi
Published: March 2003

A new-type oxidation-reduction condensation by using 2,6-dimethyl-1,4-benzoquinone (DMBQ), carboxylic acids and in situ formed alkoxydiphenylphosphines (1) including the bulky alkoxy group-substituted ones proceeded smoothly to afford the corresponding carboxylic acid esters in good to high yields. Alkoxydiphenylphosphines were formed in situ by treating either N,N-dimethylaminodiphenylphosphine (Ph2PNMe2) with primary or secondary alcohols or chlorodiphenylphosphine with the lithium salts of primary, secondary and tertiary alcohols.
Intramolecular Fluorescent Resonance Energy Transfer (FRET) by BODIPY Chemical Modification of Cysteine-engineered Mutants of Green Fluorescent Protein
Authors: Suzuki Miho , Ito Yoichiro , Savage Hannah Elizabeth , Husimi Yuzuru , Douglas Kenneth T
Published: March 2003

Green Fluorescent Proteins (GFP) bearing an intramolecular BODIPY fluorophore partner were designed by molecular modeling based on GFP’s three-dimensional structure, and prepared by mutating out native Cys-48 found at the GFP surface (replaced by Ala or Ser) and introducing new specific, surface cysteine residues for chemical modification by a thiol-directed fluorescent BODIPY 507/545 label. This gave derivatives which exhibited strong intramolecular fluorescence resonance energy transfer with quenching of the emission peak of GFP at 508 nm and the appearance of a new FRET emission from the conjugated BODIPY 507/545 around 530 nm.
Preparation and Thermal Dehydration of N-(Carboxy)acyl Chitosan Derivatives with High Stereoregularity
Authors: Satoh Taku , Vladimirov Leonid , Johmen Masayoshi , Sakairi Nobuo
Published: March 2003

Complete N-acylation of chitosan has been achieved by treating with cyclic acid anhydrides in aqueous homogeneous media at pH 4 to 8. Some of the resulting N-(carboxy)acyl chitosans were successfully converted into the corresponding imido forms by thermal dehydration.
A Mild Solution Route to Bismuth Selenoiodide Rod-like Crystals
Authors: Zhu Liying , Zheng Xiuwen , Yin Xing , Liu Xiang , Jia Yunbo , Xie Yi
Published: March 2003

Bismuth selenoiodide (BiSeI) millimeter-scale rod-like crystals were synthesized for the first time via a mild solution route based on the reactions of BiCl3, Se with NaI or Bi2Se3 with BiI3 in ethanol solvent at 200 °C. A possible growth mechanism of the rod-like BiSeI was proposed.
Cause, type, and workers' compensation costs of injury to fire fighters
Authors: Walton Surrey M. , Conrad Karen M. , Furner Sylvia E. , Samo Daniel G.
Published: March 2003

Background

Work‐related injury rates in the fire service industry exceed those for most other industries, however little is known about the cost of injury to firefighters.

Methods

This is a preliminary investigation of detailed worker's compensation records of firefighter injuries, 1,343 claims in all, collected from 1992–1999. Summary statistics and regression analysis regarding the cause, nature, and cost of injury to firefighters are presented.

Results

Overexertion accounted for a significant portion (over 1/3) of injuries to firefighters, typically involved injuries to the back, and was associated with significantly higher costs than other types of injuries. The per‐claim average worker's compensation cost of injury to firefighters was $5,168 and the average for injuries caused by overexertion was $9,715.

Conclusions

Overexertion is a costly source of injury to firefighters that can likely be reduced through policy intervention. Am. J. Ind. Med. 43:454–458, 2003. © 2003 Wiley‐Liss, Inc.
Sex offenders and actuarial risk assessments: ethical considerations
Authors: Campbell Terence W.
Published: March 2003

When assessing the recidivism risk of previously convicted sex offenders, the relevant ethical standards and practice guidelines obligate psychologists to acknowledge numerous limits related to their data and conclusions. For the actuarial instruments used in these assessments, the highest rates of classification accuracy are associated with greater specificity compared with sensitivity. Selecting cut‐off scores to maximize sensitivity results in an inordinate frequency of false positive classifications. Attempts at maximizing specificity create an undesirable frequency of false negative classifications.

Unfortunately, adjusted actuarial assessment cannot remedy these problems created by the sensitivity–specificity tradeoff. As an unstandardized procedure, the accuracy of adjusted actuarial assessment is severely limited. Consequently, civil proceedings for previously convicted sexual offenders rely on assessments of very limited accuracy. Undertaking these assessments, therefore, may be inconsistent with relevant ethical standards and practice guidelines. Copyright © 2003 John Wiley & Sons, Ltd.
Novel Carboranyl C‐Glycosides for the Treatment of Cancer by Boron Neutron Capture Therapy
Authors: Tietze Lutz F. , Griesbach Ulrich , Schuberth Ingrid , Bothe Ulrich , Marra Alberto , Dondoni Alessandro
Published: March 2003

The synthesis of the novel unprotected carboranyl C‐glycosides 2 and 20–24 starting from ethynyl C‐glycosides 1, 5–8, 10, and 13 is described. The new compounds are highly water‐soluble and display only a very low cytotoxicity, which makes them promising candidates for use in boron neutron capture therapy for the treatment of cancer.
Identification and Characterization of Monomeric, Volatile SiCl3NH2 as Product of the Reaction between SiCl4 and NH3: An Important Intermediate on the Way to Silicon Nitride?
Authors: Himmel Hans‐Jörg , Schiefenhövel Nils , Binnewies Michael
Published: March 2003

We studied the reaction of SiCl4 with NH3 by mass spectrometry and IR spectroscopy. By means of mass spectrometry, SiCl3NH2 was for the first time identified as an intermediate generated in significant amounts in the course of the reaction. In additional experiments, SiCl3NH2 was formed as a stable gaseous product of the ammonolysis of SiCl4, and the product was identified and characterized in detail by IR spectroscopic methods (gas phase and matrix isolation) in combination with quantum‐chemical calculations. The calculations also gave access to important thermodynamical data.
Reinventing Phenanthroline Ligands − Chiral Derivatives for Asymmetric Catalysis?
Authors: Schoffers Elke
Published: March 2003

Over the last three decades, the rational design of chiral ligands for asymmetric catalysis has increasingly replaced the trial‐and‐error approach. A well‐known analytical reagent, 1,10‐phenanthroline, is now being employed as a template for the development of chiral ligands. In most cases these heterocyclic ligands have been functionalized in the peripheral region utilizing three prevailing ligand templates. Chiral groups are either introduced in the 2‐, 3‐, 8‐ and/or 9‐position (I, II) or are incorporated by ring fusion to phenanthroline (III). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis of New Enantiopure Bicyclic 1,2‐Oxazines by Addition of Lithiated Methoxyallene to Chiral Cyclic Nitrones
Authors: Pulz Robert , Cicchi Stefano , Brandi Alberto , Reißig Hans‐Ulrich
Published: March 2003

A highly diastereoselective addition of lithiated methoxyallene 3 to chiral cyclic nitrones 1 and 2 provided N‐hydroxy pyrrolidines 4 and 5, respectively, which cyclized to bicyclic 1,2‐oxazines 6 and 7 by simple stirring in dilute CH2Cl2 solution. Storage of 4 in a more concentrated solution led to formation of a 60:40 mixture of 1,2‐oxazine 6 and amine oxide 8. Hydroboration of 7 furnished the hydroxy‐substituted bicyclic 1,2‐oxazine 9 with excellent diastereoselectivity. Hydrogenolysis of 6 provided the substituted pyrrolidine derivative 10. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Titanium‐Mediated Carboxylation of Alkynes With Carbon Dioxide
Authors: Six Yvan
Published: March 2003

The regioselective carboxylation of nonactivated internal alkynes can be performed with carbon dioxide under atmospheric pressure using a simple procedure based on the chemistry of Sato‐type diisopropyloxytitanacyclopropenes. Various polysubstituted vinylcarboxylic acids and butenolides can be prepared in this way. In addition, this paper describes an experimental protocol for the preparation of solutions of (η2‐cyclopentene)diisopropyloxytitanium. This complex also reacts with carbon dioxide, and mediates pinacol coupling of acetophenone. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Transitivity, flexibility, conjunctive representations, and the hippocampus. I. An empirical analysis
Authors: Van Elzakker Michael , O'Reilly Randall C. , Rudy Jerry W.
Published: March 2003

After training on a set of four ordered, simultaneous, odor discrimination problems (A+B−, B+C−, C+D−, D+E), intact rats display transitivity: When tested on the novel combination BD, they choose B. Rats with damage to the hippocampus, however, do not show transitivity (Dusek and Eichenbaum, 1997. Proc Natl Acad Sci U S A 94:7109–7114). These results have been interpreted as support for the idea that the hippocampus is a relational memory storage system that enables the subject to make comparisons among representations of the individual problems and choose based on inferential logic. We provide evidence for a simpler explanation. Specifically, subjects make their choices based on the absolute excitatory value of the individual stimuli. This value determines the ability of that stimulus to attract a response. This conclusion emerged because after training on a five‐problem set (A+B−, B+C−, C+D−, D+E−, E+F−) rats preferred B when tested with BE, but not when tested with BD. The implication of these results for how to conceptualize the role of the hippocampus in transitive‐like phenomena is discussed. Hippocampus 2003;13:334–340. © 2003 Wiley‐Liss, Inc.
Phorbol ester uncouples adenosine inhibition of presynaptic Ca2+ transients at hippocampal synapses
Authors: Stocca Gabriella , Lovinger David M.
Published: March 2003

Synaptic transmission involves Ca2+ influx at presynaptic terminals. Adenosine receptors inhibit transmission, and this effect can be abolished by activation of PKC with phorbol esters. Whether protein kinase C (PKC) acts via alterations in Ca2+ entry at the presynaptic terminal is unknown. In the present study, we recorded the presynaptic Ca2+ transients (preCaΔ) in hippocampal stratum radiatum, using fluorescence photometry. The calcium dye Fura‐2 AM was used to load the Schaffer collateral/commissural tract and its terminals. Tetrodotoxin (TTX)‐sensitive Na+ channels and Cd2+‐sensitive, high‐voltage activated Ca2+ channels (HVACCs) were required to elicit the preCaΔ. Application of the phorbol ester phorbol‐12,13‐dibutyrate (PDBu) abolished the adenosine inhibition of both preCaΔ and the field excitatory postsynaptic potentials (fEPSPs). PDBu consistently potentiated fEPSPs, and also increased preCaΔ in a large majority of the slices examined. Regardless of whether potentiation was observed, PDBu always prevented adenosine inhibition of preCaΔ. In contrast, the inactive phorbol ester, 4α‐phorbol, did not alter adenosine inhibition of preCaΔ, indicating that PKC activation is necessary for the occurrence of the observed effects. Our findings suggest that PKC activation abolishes adenosine's inhibitory effect on synaptic activity involving presynaptic Ca2+ entry. Hippocampus 2003;13:355–360. © 2003 Wiley‐Liss, Inc.
Multiple structural states of S100A12: A key to its functional diversity
Authors: Moroz O.V. , Dodson G.G. , Wilson K.S. , Lukanidin E. , Bronstein I.B.
Published: March 2003

S100A12 is a member of the S100 family of EF‐hand calcium‐binding proteins. Together with two other calgranulins, S100A8 and S100A9, it is mostly expressed in human granulocytes, although there is increasing evidence of expression in keratinocytes and psoriatic lesions. It is involved in host‐parasite response, and linked to corneal autoimmune diseases connected with filarial parasite infestation. Interaction of S100A12 with a multiligand receptor for advanced glycation end products (RAGE) mediates inflammation. Human recombinant S100A12 was found to induce neuritogenesis of cultured hippocampal cells, similar to two other S100 proteins, S100B and S100A4. X‐ray structure of S100A12 has been solved in two crystal forms: R3 and P21. In the R3 crystal form S100A12 is a dimer, and in the P21 crystal form the dimers are arranged as a hexamer. The hexameric form suggests its role in receptor oligomerisation. S100A12 binds copper at the predicted zinc/copper binding site, which is located close to the surface of the protein. We propose copper‐mediated generation of reactive oxygen species by S100A12 as its function in host‐parasite response. Microsc. Res. Tech. 60:581–592, 2003. © 2003 Wiley‐Liss, Inc.
Detection of tyrosine phosphorylated peptides via skimmer collision‐induced dissociation/ion trap mass spectrometry
Authors: Zolodz Melissa D. , Wood Karl V.
Published: March 2003

Phosphorylation of proteins is an important post‐translational protein modification in cellular response to environmental change and occurs in both prokaryotes and eukaryotes. Identification of the amino acid on individual proteins that become phosphorylated in response to extracellular stimulus is essential for understanding the mechanisms involved in the intracellular signals that these modifications facilitate. Most protein kinases catalyze the phosphorylation of proteins on serine, threonine or tyrosine. Although tyrosine phosphorylation is often the least abundant of the three major phosphorylation sites, it is important owing to its role in signal pathways. Currently available methods for the identification of phosphorylation sites can often miss low levels of tyrosine phosphorylations. This paper describes a method for the identification of phosphotyrosine‐containing peptides using electrospray ionization on an ion trap mass spectrometer. Skimmer‐activated collision‐induced dissociation (CID) was used to generate the phosphotyrosine immonium ion at m/z 216. This method is gentle enough that the protonated molecule of the intact peptide is still observed. In‐trap CID was employed for the verification of the phosphotyrosine immonium ion. Using this technique, low levels of phosphotyrosine‐containing peptides can be identified from peptide mixtures separated by nanoflow micro liquid chromatography/mass spectrometry. Copyright © 2003 John Wiley & Sons, Ltd.
Gas‐phase theoretical prediction of the metal affinity of copper(I) ion for DNA and RNA bases
Authors: Russo Nino , Toscano Marirosa , Grand André
Published: March 2003

The most stable tautomeric forms of free DNA and RNA bases were considered as substrates for the interaction of Cu+ ion. Several suitable attachment sites were selected that involved mono‐ and bi‐coordination of the cation. B3LYP/6–311 + G(2df,2p) bond energies showed that copper ion has the major affinity for guanine and cytosine bases. The proposed values of Cu+ ion affinity are 59.9, 60.0, 80.2, 88.0 and 69.0 kcal mol−1 for uracil, thymine, cytosine, guanine and adenine, respectively. The preference for the mono‐ or bi‐coordination depends on the particular tautomer for each base. Copyright © 2003 John Wiley & Sons, Ltd.