bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinetics of Electrochemical Reductive Dissolution of Iron(III) Hydroxy-oxides
Authors: Grygar Tomáš
Published: July 2002

Abrasive stripping voltammetry was applied to the chronoamperometric and voltammetric investigation of the kinetics of reductive dissolution of synthetic and natural iron(III) hydroxy-oxides. Conditions were found under which the dissolution process can be described by equations derived for and applied to the surface reaction of the particles. The rate constants obtained were employed to compare the electrochemical and chemical reductive dissolution and to quantitatively evaluate the effect of adsorbing ions, pH, and working electrode potential.
The (η-1,7'-2,2')4,8'-8,4'-(Bis-μ-o-phenylene)bisdicarbollidocobalt(1-)ate Ion [3-Co-4,8'-8,4'(o-C6H4)2(1,2-C2B9H9)2](-). The First Doubly Bridged Metallacarborane Complex. Synthesis, Properties and Structure
Authors: Plešek Jaromír , Heřmánek Stanislav
Published: July 2002

The first cobaltacarborane sandwich complex [3-Co-4,8'-8,4'(o-C6H4)2(1,2-C2B9H9)2](-) with two o-phenylene bridges between both deltahedral ligands is described. Phenylene rings containing angle of 72 grad bind the Cs counter-ion probably via π-donation. This is why the solubility of Cs salt in water is extremely low. Synthesis, properties and structure of the Cs salt are described.
Extraction of Dithiocarbamate Chelates of Ni(II), Cu(II), Zn(II)
Authors: Oktavec Drahomír , Lehotay Jozef , Vrábel Viktor , Korgová Elena
Published: July 2002

Extraction has been investigated of chelates of alkali salts of dithiocarbamic (DTC) acids derived from (R-) dimethyl-, diethyl-, dipropyl-, diisopropyl-, dibutyl-, diisobutyl-, dipentyl-, and dihexylamine, piperidine, and morpholine with Ni(II), Cu(II), and Zn(II) from aqueous solutions of various pH values into chloroform for various time intervals. The optimum conditions have been determined for the maximum extraction yields of the metal connected with the minimum extraction yields of excess DTC ligand. The extraction of DTC chelates of Ni(II), Cu(II), and Zn(II) is best accomplished in a reaction period of 4.5 min in strong acid region (Ni, Cu) or in alkaline region with buffers of pH 8.5-9.0 (Zn). The advantage of DTC as compared with many other reagents lies in the possibility of quantitative extraction of Ni(II) and Cu(II) from strong acid media since in this region the excess DTC ligand is completely decomposed to carbon disulfide and amine in short time, and thus it does not interfere with the subsequent spectrophotometric determination.
Catalyst Effects on the Stereoselectivity of Addition of Tetrachloromethane to 1,3-Cyclohexadiene
Authors: Hájek Milan , Kotora Martin , Adámek František , Davis Reg , Fischer Cecile , Joshu Warren A. C.
Published: July 2002

The stereoselectivity of addition reaction of tetrachloromethane with conjugate cyclodienes represented by 1,3-cyclohexadiene has been studied in respect to the type of catalyst. In all addition reactions the product of 1,4-addition, i.e. 1-chloro-4-(trichloromethyl)cyclohex-2-ene was formed exclusively consisting of two isomers (1a, 1d). Copper-amine complexes gave higher isomeric ratio 1a : 1d (up to 3.7) than ruthenium complex (1.3) at the same conditions (80 °C). Moreover, it was found that isomeric ratio was temperature dependent and the highest value (6.4) was obtained at lower temperature (20 °C). The results proved both catalyst and ligand effects on stereoselectivity of addition reaction of conjugated cyclic dienes. This supports a non-chain reaction mechanism because isomeric ratios of chain reactions are catalyst independent.
Electroreduction of 3-Bromopyrene in DMF. A New Organic Electrochemical Oscillator
Authors: Jaworski Jan S. , Leszczynski Piotr , Pawlowski Slawomir
Published: July 2002

The reduction of 3-bromopyrene in DMF at a mercury electrode for scan rates lower than 0.1 V s-1 is accompanied by a slow adsorption of an intermediate, resulting in a catalytic behaviour. The current oscillations take place in a region of the negative faradaic impedance.
Alkaloids of Meconopsis cambrica (L.) VIG. and M. robusta HOOK. f. et THOMS.
Authors: Slavík Jiří , Slavíková Leonora
Published: July 2002

Additional alkaloids (+)-roemerine (3b), (+)-corytuberine (3d), (-)-N-methylmecambridinium and alkaloid MC 2 (the last two as iodides) were isolated as minor alkaloidal components from Meconopsis cambrica (L.) VIG. (Papaveraceae) besides of the dominant known alkaloids (-)-mecambrine (1), (-)-mecambridine (2), (-)-flavinantine (4) and (+)-magnoflorine (5), and a small amount of (+)-mecambroline (3a). Minute quantities of protopine, allocryptopine, roemeroline, papaverrubine D and C, berberine, coptisine, corysamine and palmatine were identified by thin layer chromatography (TLC). From M. robusta HOOK. f. et THOMS., protopine, (-)-amurensinine (6) and two incompletely characterized alkaloids MRO 1 and MRO 2 were isolated, and allocryptopine, cryptopine, rhoeadine, 6-methoxy-2-methyl-1,2,3,4-tetrahydro-β-carboline, alkaloid MR 1, coptisine, corysamine, magnoflorine, corytuberine and N-methylamurensininium salt were detected on TLC.
Titration of Mercaptans and Some Mercaptan-Based Drugs with Iodine Monobromide in Non-Aqueous Dimethyl Sulfoxide
Authors: Sharma D. K. , Sambra B. S. , Verma N. , Verma B. C.
Published: July 2002

Mercaptans undergo smooth and quantitative oxidation to the corresponding disulfides with iodine monobromide in non-aqueous (dimethyl sulfoxide) medium, which has been made the basis of a simple, rapid and rugged method for the determination of mercaptan-based drugs viz. mercaptopurine and dimercaprol. The method has been thoroughly tested with a number of mercaptans before applying it to drugs. The salient features of the method are discussed.
Synthesis and Infrared and 1H, 13C, 119Sn NMR Spectra of Some Tris- and Bis(1-butyl)tin(IV) Naphthoates and Hydroxynaphthoates
Authors: Holeček Jaroslav , Nádvorník Milan , Handlíř Karel , Pejchal Vladimír , Vítek Radovan , Lyčka Antonín
Published: July 2002

The synthesis and structure of tris(1-butyl)tin(IV) and bis(1-butyl)tin(IV) 1-naphthoates, 2-naphthoates, 1-hydroxy-2-naphthoates, 2-hydroxy-1-naphthoates, 3-hydroxy-2-naphthoates as well as the groups of the corresponding tetrakis(1-butyl)dinaphthoato- and tetrakis(1-butyl)bis(hydroxynaphthoato)distannoxanes have been studied in solutions of both coordinating and noncoordinating solvents by means of infrared and multinuclear (1H, 13C and 119Sn) NMR spectroscopies. In the solutions of noncoordinating solvents, all the tris(1-butyl)tin(IV) compounds are present as isolated monomeric molecules with pseudotetrahedral environment of the central tin atom, or as strongly deformed cis-trigonally bipyramidal chelate complexes with anisobidentate carboxylic group. The bis(1-butyl)tin(IV) compounds form molecular pseudooctahedral complexes with chelate anisobidentate carboxylic groups of naphthoate or hydroxynaphthoate ligands. The (1-butyl)chlorotin(IV) compounds are molecular complexes containing a chelate-bound carboxylic group, their tin atom having a pentacoordinated environment of the bond partners. The tetrakis(1-butyl)dinaphthoato- and tetrakis(1-butyl)bis(hydroxynaphthoato)distannoxanes form dimeric molecular complexes with two pentacoordinated tin atoms and two hexacoordinated ones. In solutions of a coordinating solvent (hexadeuteriodimethyl sulfoxide), the tris(1-butyl)tin(IV) compounds form trans-trigonally bipyramidal complexes with one molecule of the solvent, whereas the bis(1-butyl)tin(IV) and bis(1-butyl)chlorotin(IV) compounds form trapezoidally bipyramidal complexes with two molecules of the solvent. The dimeric tetrakis(1-butyl)bis(hydroxynaphthoato)distannoxanes are monomerized by coordinating solvent, each monomeric unit adding two solvent molecules per one tin atom. The environment of the tin atom is then pseudooctahedral. The hydroxyl groups of naphthoate systems do not take part in any bonds to the tin atom in any of the compounds studied.
Laboratory Oxidation of Fossil Organic Matter Studiedby in situ Infrared Spectroscopy, Rock-Eval Pyrolysis and Pyrolysis-Gas Chromatography-Mass Spectrometry
Authors: Čejka Jiří , Sobalík Zdeněk , Kříbek Bohdan
Published: July 2002

Fossil organic matter in Miocene and Silurian sediments was subjected to experimental oxidation, which was investigated by Rock-Eval pyrolysis, the "off-line" pyrolysis-gas chromatography-mass spectrometry combination, and continuous FTIR monitoring. The pyrolysate yield decreased during the oxidation particularly in the low-matured, predominantly aliphatic organic matter from the Miocene sediments (type I kerogen, algae-type kerogen). This suggests that aliphatic chains are preferentially oxidized, which is in agreement with the marked decrease in the intensity of the v(CH2) and v(CH3) IR bands. The n-alkane distribution in the chromatographic profile was unaffected by the oxidation; hence, the oxidation of the alkane chains was not selective. At the same time, the bands within the 1 900-1 550 cm-1 range grew in intensity for both the aliphatic and mixed-type (type II kerogen) organic matter. The oxidation of the aromatic (humic) type of organic fossil matter in the Miocene sediments (type III kerogen, coal-type kerogen) was only accompanied by very small changes in the FTIR spectra. The results of the "of-line" pyrolysis are consistent with those of the Rock-Eval pyrolysis. For all samples, the oxidation was accompanied by a gradual decrease in the hydrogen index (HI) as well as in the pyrolysis temperature maximum (Tmax). The changes in the S2/S1 ratio ("bound"-to-"free" hydrocarbons) indicate that the "free" hydrocarbons in the rocks are preferentially oxidized during the first 8-16 h of the experimental run. Subsequently, hydrocarbon chains involved in the kerogen macromolecule are attacked.
Polarographic and Voltammetric Determination of N,N-Dimethyl-4-amino-4'-sulfoazobenzene
Authors: Barek Jiří , Hai Pham Tuan , Mejstřík Viktor , Moreira Josino C. , Zima Jiří
Published: July 2002

The polarographic behaviour of N,N-dimethyl-4-amino-4'-sulfoazobenzene was investigated by tast polarography and differential pulse polarography at a dropping mercury electrode, constant-potential coulometry at a large area mercury electrode and cyclic voltammetry at a hanging mercury drop electrode. Optimum conditions have been found for its determination by tast polarography in the concentration range of 2-100 μmol l-1, differential pulse polarography at a dropping mercury electrode in the concentration range of 0.2-100 μmol l-1 and by differential pulse voltammetry at a hanging mercury drop electrode in the concentration range of 0.02-10 μmol l-1. The sensitivity of the determination can be further improved by adsorptive accumulation of the test substance on the hanging mercury drop electrode. Three-minute accumulation in stirred solution allows determination in the range of 0.2-100 nmol l-1.
Chronopotentiometric Study of EC Mechanism Duringthe First Cycle of Alternating Current
Authors: Molina Ángela , Martínez-Ortiz Francisco , Ruiz Ricardo , López-Tenés Manuela
Published: July 2002

The theoretical approach to the application of the first period of a sinusoidal current at static and dynamic spherical electrodes for study of EC mechanism is presented. Methods for determining heterogeneous and homogeneous kinetic parameters are proposed. In order to check theoretical result, the rate of benzidine rearrangement was evaluated from transition time measurements.
Single-Step Separation of Lactate Dehydrogenase Using Thiophilic Chromatography
Authors: Kmínková Milena , Kučera Jiří
Published: July 2002

Lactate dehydrogenase (EC 1.1.1.27) from carp (Cyprinus carpio) hepatopancreas was purified by the single-step chromatography on thiophilic sorbent. Hydrophobic negative sorption was used as negative adsorption step for final purification. Final specific activity was 8.88 U/mg protein and the yield 84%. The enzyme is not adsorbed during hydrophobic interaction chromatography, but proteolytic activity is adsorbed completely on hydrophobic sorbent. Thus hydrophobic adsorption can be used as a prepurification step.
In situ Mössbauer Study of the Passive Layer Formed on the Iron Anode in Alkaline Electrolyte
Authors: Bouzek Karel , Nejezchleba Martin
Published: July 2002

In situ Mössbauer spectra of the iron electrode at anodic potential were measured in sodium hydroxide solution over a wide range of concentrations (0.1 - 14 mol l-1). It was found that the in situ Mössbauer spectra exhibit generally one sextet and one doublet corresponding to the oxide layer on the anode surface. Parameters of these spectra show only minor variations within the electrolyte concentration range of 0.1 - 7 M NaOH. A pronounced change in the spectra was observed in 14 M NaOH. The major processes taking place in the anode surface layer are based on the break-down of protective properties of the passive layer, incipient intense metal dissolution and subsequent oxidation. Important differences were also found between in situ and ex situ spectra measurements.
Chemometrical Analysis of Substituent Effects. XIII. Comparison of Substituent Effects on Dissociation and Chemical Shift in 13C NMR Spectra of Mono- and Disubstituted Benzoic Acids
Authors: Kulhánek Jiří , Pytela Oldřich , Lyčka Antonín
Published: July 2002

The 13C chemical shifts have been measured of the carboxyl carbon atoms for all the 2-, 3-, and 4-substituted benzoic acids with H, CH3, CH3O, F, Cl, Br, I, and NO2 substituents, as well as for all 3,4-, 3,5-, and 2,6-disubstituted benzoic acids with combinations of CH3, CH3O, Cl (or Br), NO2 substituents and for symmetrically 2,6-disubstituted derivatives with Et, EtO, PrO, i-PrO, and BuO substituents. The chemical shifts of carboxylic group carbon atoms of the 3- and 4-substituted derivatives show correlation only with the substituent constants σI. For the 2-substituted derivatives was found the dependence only on σI and on the υ constant describing steric effects (s = 0.122, R = 0.996, without the CH3 derivative which has a distinct anisotropic effect). The substituent effects on the carboxylic carbon chemical shift show additivity with 3,4-, 3,5-, and 2,6-substituents, and the 2,6-disubstituted derivatives show a linear synergic effect of substituents due obviously to the steric hindrance to resonance. Application of the principal component analysis to the data matrix involving all the combinations of mono- and disubstitution involving the above-mentioned substituents has proved an identical substituent effect from all the positions on the chemical shift described by one latent variable, steric effects and anisotropic behaviour of methyl at the 2 and 2,6 positions being predominantly described by the second latent variable (with the total explained variability of 99.5%). Comparison of substituent effects on the chemical shift of carboxylic carbon with that on the dissociation constant measured in the same solvent has confirmed the anisotropy due to ortho methyl group, the ortho halogen substituents in monosubstituted derivatives also having a different effect. The dependence of chemical shift on pKa was not very close for the derivatives studied (s = 1.005, R = 0.690). The inclusion of anisotropy of ortho alkyl group by means of an indicator variable improved the correlation (s = 0.533, R = 0.925), and omitting of 2-F, 2-Cl, 2-Br, and 2-I substituents gave a regression without deviating points (s = 0.352, R = 0.968).
Catalytic and Stoichiometric Lewis Acid Participation in Aldehyde Ene Cyclisations
Authors: Braddock D. Christopher , Brown John M.
Published: July 2002

Racemic 2-isopropyl-2-methylhex-5-enal has been synthesised in order to probe ene cyclisations leading to menthol analogues. The objective was first to discover catalytic conditions for preferential cyclisation to the menthol rather than the neomenthol series and then to develop (dynamic) kinetic resolution procedures which afforded a single enantiomer of product. It was found that catalytic quantities of both Me2AlCl and a bulky methylaluminium bis(phenoxide) reagent gave products attributed to a Meerwein-Pondorff-Verley reaction. In this the aldehyde is reduced to a primary alcohol and the ene product oxidised to the corresponding α,β-unsaturated ketone. By contrast, a related bulky chloroaluminium reagent catalysed the ene cyclisation cleanly, but preferentially to the undesired neomenthyl stereoisomer.
Synthesis of 8,14-Secosteroids from (S)-(+)-Carvone
Authors: Kotyatkina Anna I. , Zhabinskii Vladimir N. , Khripach Vladimir A. , Groot Aede de
Published: July 2002

A total synthesis of functionalised 8,14-seco steroids with five- and six-membered D rings is described. The synthesis is based on the transformation of (S)-carvone into a steroidal AB ring moiety with a side chain at C-9 that allowed the creation of a nitrile oxide at this position. The nitrile oxides were coupled with cyclic enones or enol derivatives of 1,3-diketones, and reductive cleavage of the obtained cycloadducts gave the desired products. The formation of a twelve-membered ring compound was observed in cycloaddition of one of the nitrile oxides with cyclopentenone as the result of an intramolecular ene-reaction followed by retroaldol reaction.
Convenient and Stereospecific Synthesis of trans-1,3-Disubstituted Imidazolidines and Their Transformation to 2,3-Diamino-3-phenylpropanoic Acids
Authors: Kavrakova Ivanka K. , Lyapova Maria J.
Published: July 2002

Conversion of the easily available trans-2-oxoimidazolidine-4-carboxylic acid 1 to the corresponding imidazolidines 8 gives after one-step oxidation and ring cleavage the diamino acid 2 in high yield. The difference in the trans-vicinal couplings for the hydrogen-bonded and nonbonded compounds suggests different ring geometry as a result of the balancing effect of the N1 substituent on the "allylic strain".
Synthesis of Symmetrical Bis-Steroid Pyrazines Connected via D-Rings
Authors: Černý Ivan , Pouzar Vladimír , Buděšínský Miloš , Drašar Pavel
Published: July 2002

Bis-steroid pyrazines fused through rings D of the steroid skeleton were synthesized. Methods for the preparation of the corresponding rings A fused derivatives (cephalostatin type) were checked on simple androstanes and then a symmetrical D fused analogue, 5α-androstano[16'',17''-5',6']pyrazino[2',3'-16,17]-5α-androstane-3β,3''b-diol, was prepared. Partially substituted bis-steroid pyrazines in both series were prepared and their use for the preparation of higher fused compounds was discussed. No significant cytostatic activity was found on parent bis-steroid pyrazines both A and D fused.
Synthesis of Normuramic Acid Carba Analog and Its Glycopeptide Derivative Resistant to β-Elimination Splitting of the Side Chain
Authors: Ledvina Miroslav , Pavelová Radka , Rohlenová Anna , Ježek Jan , Šaman David
Published: July 2002

Carba analogs of normuramic acid, i.e., 3-(benzyl 2-acetamido-2,3-dideoxy-4,6-O-isopropylidene-α-D-glucopyranosid-3-yl)propanoic acid derivatives (nitrile or esters) 3a-3c were prepared by addition of radicals generated from benzyl 2-acetamido-2-deoxy-4,6-O-isopropylidene-3-O-[(methylsulfanyl)thiocarbonyl]- (2a) or -3-O-(phenoxythiocarbonyl)-α-D-glucopyranoside (2b) with Bu3SnH to acrylonitrile or acryl esters. Alkaline hydrolysis of ethyl ester 3c afforded 3-(benzyl 2-acetamido-2,3-dideoxy-4,6-O-isopropylidene-α-D-glucopyranosid-3-yl)propanoic acid (5). Coupling of acid 5 with L-2-aminobutanoyl-D-isoglutamine benzyl ester trifluoroacetate and subsequent deprotection of the intermediate 6 furnished N-[3-(2-acetamido-2,3-dideoxy-α-D-glucopyranosid-3-yl)propanoyl]-L-2-aminobutanoyl-D-isoglutamine (7).
Spin Coupling Interactions in Transition Metal Complexes Containing Radical o-Semiquinone Ligands. A Review
Authors: Pierpont Cortlandt G. , Attia Attia S.
Published: July 2002

Transition metal complexes ofo-semiquinone (SQ) ligands have been studied extensively over the past 25 years. A particularly interesting aspect of this coordination chemistry concerns magnetic interactions between paramagnetic metal ions and the radical anionic ligands. In this review we begin with a survey of relatively simple complexes consisting of a paramagnetic metal ion chelated by a single SQ ligand. Recent studies have revealed the importance of SQ-SQ coupling through diamagnetic metals, and complexes of this class are described in the second section of the review. Both interactions combine to account for the often complicated magnetic properties of complexes containing multiple SQ ligands chelated to a paramagnetic metal ion. Research on these complexes is surveyed in the third section with a concluding look toward polymeric SQ complexes. A review with 51 references.
A Facile Synthesis of Azetidin-2-ylphosphonic Acid and Its 1-Alkyl Derivatives
Authors: Otmar Miroslav , Poláková Lucie , Masojídková Milena , Holý Antonín
Published: July 2002

Treatment of racemic diisopropyl [1,3-bis(mesyloxy)propyl]phosphonate with allyl-, benzyl-, 2-hydroxyethyl-, or propylamine gave the corresponding diisopropyl [(3-(alkylamino)-1-(mesyloxy)propyl]phosphonates. Heating of their toluene solution with aqueous potassium carbonate effected a cyclization to diisopropyl (1-alkylazetidin-2-yl)phosphonates. In the 1-benzyl- and [1-(2-hydroxyethyl)azetidin-2-yl]phosphonate, the isopropyl ester groups were removed by treatment with bromotrimethylsilane which gave 1-benzyl- and [1-(2-hydroxyethyl)azetidin-2-yl]phosphonic acid. Following hydrogenolysis of the benzyl group afforded azetidin-2-ylphosphonic acid.
Synthesis of Norhydroperoxides from Natural Triterpenic Acids
Authors: Tatarov Eugene S. , Tkachev Alexey V.
Published: July 2002

Treatment of triterpenoids derived from ursolic and glycyrrhetinic acids with the oxidative mixture H2O2-(CF3COO)2Hg-Na2CO3-THF results in oxidative decarboxylation. The reaction of 3O-acetylursolic acid (1) and 3O-acetyl-18β-glycyrrhetinic acid (3) affords stable norhydroperoxides, whereas decarboxylation of 3O-acetyl-11-oxoursolic acid (6) leads to unstable norhydroperoxide. The difference in properties of the norhydroperoxides is explained by the presence of a conjugated ketone, which activates the 12,13-C=C double bond for nucleophilic addition and makes possible intramolecular Michael-type addition of peroxo anion.
π-Facial Selectivity in 1,3-Dipolar Cycloaddition Reactions of α-Methylidene-γ-lactone Substituted by 4-Methyl-2,6,7-trioxabicyclo[2.2.2]octan-1-yl Group in γ-Position
Authors: Melša Petr , Mazal Ctibor
Published: July 2002

Diastereoselectivity of 1,3-dipolar cycloaddition reactions of benzyl azide, diazomethane, a nitrile oxide and a nitrile imine to α-methylidene-γ-lactone dipolarophile was effectively controlled by a bulky γ-substituent, 4-methyl-2,6,7-trioxabicyclo[2.2.2]octan-1-yl in γ-position of the dipolarophile. The dipoles added from the less hindered face of the double bond with an excellent selectivity. Enantiomerically pure dipolarophile was prepared from the easily available (S)-5-oxotetrahydrohydrofuran-2-carboxylic acid.
Sural nerve injury associated with neglected tendo Achilles ruptures
Authors: Fletcher M D A , Warren P J
Published: July 2002

Two patients are described with delayed presentation of a ruptured tendo Achilles, each exhibiting signs of sural nerve dysfunction. Recovery occurred in each case after operative repair.
Phaeochromocytoma unearthed by fluoxetine
Authors: Kashyap A S
Published: July 2002

Non-specific noradrenaline reuptake inhibition by high dose selective serotonin reuptake inhibitors, along with catecholamine release from phaeochromocytoma, may lead to a hypertensive paroxysm. This may unmask a clinically silent phaeochromocytoma. Hypertensive paroxysm induced by paroxetine leading to detection of phaeochromocytoma has been reported. The first patient in whom fluoxetine unmasked a phaeochromocytoma is reported.
Modern management of oesophageal varices
Authors: Gow P J , Chapman R W
Published: July 2002

Haemorrhage from oesophageal varices is a life threatening emergency with a mortality rate in the order of 30%–50%. In the last three decades there have been many advances in the treatment and prevention of variceal bleeding. Over recent years the introduction of new pharmaceutical agents that reduce portal pressure, endoscopic variceal ligation, transjugular intrahepatic portosystemic shunt, and the availability of liver transplantation have further increased the therapeutic options available to the physician treating this disorder. This article reviews the literature regarding therapies available in the treatment of haemorrhage from oesophageal varices and provides guidelines to aid the physicians in clinical decision making.
Failure to develop diabetic ketoacidosis in a newly presenting type 1 diabetic patient
Authors: McNulty S J , Hardy K J
Published: July 2002

An 18 year old woman presented with a two week history of polyuria, polydypsia, and accelerated weight loss. On examination she was thin, dehydrated, hypotensive (blood pressure 88/58 mm Hg), and tachycardic (pulse 130 beats/min). Random blood glucose concentration was 20.2 mmol/l and she had hyponatraemia, hyperkalaemia, and mild uraemia (consistent with diabetic ketoacidosis); however, she was not ketoacidotic (box 1). She was diagnosed as having diabetes (subsequent testing confirmed a diagnosis of type 1 diabetes mellitus) and treated with intravenous insulin and intravenous fluid. On further questioning, she admitted to a 13 month history of easy tanning, weight loss, generalised weakness, reduced appetite, and several episodes of collapse with abdominal pain.
Closure of traumatic wounds without cleaning and suturing
Authors: Maharaj D , Sharma D , Ramdass M , Naraynsingh V
Published: July 2002

Background

In less than ideal situations wounds have to be closed without extensive cleaning using sterile adhesive strips (Steristrips). This prospective analyses the efficiency of this technique and compares it to the more conventional approach.

Methods

Altogether 147 lacerations were closed with sterile strips with no wound cleaning. Patients were subsequently followed up for a minimum of three months.

Results

The sepsis rate in compliant patients was 1.4% with a total complication rate of 2.7%.

Conclusion

This technique, while contradicting the “sacred tenets” of wound closure, is a cheap, quick, and effective alternative to routine closure of traumatic wounds in a casualty department.
Genetic analysis of pathogenic and nonpathogenic Fusarium oxysporum from tomato plants
Authors: Bao Jian R , Fravel Deborah R , O'Neill Nichole R , Lazarovits George , Berkum Peter van
Published: July 2002

Forty-three Fusarium oxysporum strains and one Fusarium solani strain were analyzed for genetic diversity. These strains represent a wide range of geographic locations and were collected primarily from tomato (Lycopersicon esculentum) roots. Among all 43 F. oxysporum strains, 21 were not pathogenic to tomato, 20 were pathogenic, including 13 strains of Fusarium oxysporum lycopersici and seven strains of Fusarium oxysporum radicis-lycopersici, and two were other formae speciales of the fungus. Genetic diversity of all 43 strains was assessed by vegetative compatibility group (VCG), sequence analysis of the rDNA internal transcribed spacers (ITS1 and ITS2) and the 5.8S rRNA gene, and amplified fragment length polymorphism (AFLP). Most of the F. o. lycopersici strains were assigned to VCG 0030, while most nonpathogenic ones were incompatible with each other. ITS region analysis grouped the strains into four clusters. The nonpathogenic F. oxysporum strains were in two groups, while the pathogenic strains were placed in two different groups. Pathogenic and nonpathogenic strains were also separated into different clusters based on AFLP data, although some nonpathogenic strains grouped with pathogenic strains. The population of pathogenic strains was less diverse than that of the nonpathogenic strains, suggesting that the pathogenic strains were possibly of monophyletic origin. For both pathogenic and nonpathogenic F. oxysporum strains, no relationship was observed between the genetic profiles and geographic origin; this may indicate that pathogens did not originate independently at each locality.Key words: Fusarium oxysporum, VCG, rDNA (ITS) sequence, AFLP.
Effects of ultraviolet radiation on rates and size distribution of primary production by Lake Erie phytoplankton
Authors: Hiriart Véronique P , Greenberg Bruce M , Guildford Stephanie J , Smith Ralph EH
Published: July 2002

The impact of natural solar ultraviolet radiation (UVR), particularly UVB (297320 nm), on phytoplankton primary production in Lake Erie was investigated during the spring and summer of 1997. Radiocarbon incorporation and size-selective filtration was used to trace total production and its distribution among particulate and dissolved pools. On average, 1-h exposures produced half the UVB-dependent inhibition of total production realized in 8-h exposures, indicating rapid kinetics of photoinhibition. Cumulative UVB-dependent photoinhibition averaged 36% in 8-h simulated surface exposures. The efficiency of photoinhibition was greater for N-deficient than N-replete communities, but was not related to phytoplankton light history, P limitation, or the dominant genera. The proportion of recently fixed carbon occurring in the dissolved pool after 8-h exposures was significantly greater in higher-UVB treatments, whereas the share in picoplankton (<2 µm) was significantly lower. Significant UVB-dependent inhibition of total production was limited on average to relatively severe exposures, but the rapid kinetics of inhibition and the apparent effects on the allocation of carbon suggest it may be important to the lake's food web. Differences in optical properties and thermal stratification patterns suggested that the relatively turbid west basin was potentially more susceptible to UVR photoinhibition than the more transparent east or central basins.
Multinuclear magnetic resonance studies of the aqueous products of the complexes cis- and trans-Pt(Ypy)2(NO3)2 where Ypy = pyridine derivative
Authors: Rochon Fernande D , Tessier Christian
Published: July 2002

The hydrolyis or the aquation reactions of compounds of the types cis- and trans-Pt(Ypy)2(NO3)2 (Ypy = pyridine derivative) were studied in D2O and characterized by multinuclear (195Pt, 13C, and 1H) NMR spectroscopy. In acidic pD, the product of the cis complexes is cis-[Pt(Ypy)2(D2O)2]2+, whereas in basic medium cis-Pt(Ypy)2(OD)2 is formed. The 195Pt NMR resonances of the products containing ligands with an ortho substituent were observed at lower fields than the other complexes. The average coupling constant (3J(195Pt1H) and 3J(195Pt13C)) is 44 Hz for the diaqua species and 42 Hz for the dihydroxo compounds. At neutral pD, several hydrolyzed species were observed, except for the 2-picoline and 2,4-lutidine complexes, which contained only one compound, cis-[Pt(Ypy)2(D2O)(OD)]+. The other hydrolyzed products for the ligands with no ortho substituent were identified as the dihydroxo-bridged dimer, the monohydroxo-bridged dimer, the trimer, and possibly the tetramer. The trans analogues have shown two signals in acidic pD corresponding to the diaqua monomer and the monohydroxo-bridged aqua dimer. Two species (the dihydroxo compound and the monohydroxo-bridged hydroxo dimer) were also observed in basic pD. In neutral medium, a third signal assigned to a longer chain hydroxo-bridged oligomer or polymer was detected.Key words: platinum, pyridine derivative, nitrato, hydrolysis, NMR, aquation.
Gas-phase pyrolysis of thiopheneacetic acids, thienylethanols, and related compounds  protophilicity of ring π-electrons and relative acidities of hydrogen-bond donors of hydroxyl groups
Authors: Al-Juwaiser Ibtehal A , Al-Awadi Nouria A , El-Dusouqui Osman ME
Published: July 2002

Based on kinetic data of thermal gas-phase elimination reactions, the following Arrhenius log A (s1) and Ea (kJ mol1) values, respectively, are obtained: 10.76 and 153.5 for 3-thiopheneacetic acid (1), 10.08 and 149.4 for 2-thiopheneacetic acid (2), 12.04 and 207.1 for 2-(3-thienyl)ethanol (3), 11.55 and 203.3 for 2-(2-thienyl)ethanol (4), 10.91 and 123.4 for 2-thiopheneglyoxylic acid (5), 11.05 and 223.8 for 1-(2-thienyl)propan-1-one (6), and 10.33 and 149.8 for 3-thiophenemalonic acid (7). The products of these pyrolytic reactions were either carbon dioxide or formaldehyde in addition to methylthiophene or thiophenecarboxaldehyde. Both positional and molecular reactivities of the substrates and related compounds are compared, and the results are rationalized on the basis of a reaction pathway involving a concerted six-membered transition state.Key words: thiophenes, gas-phase, pyrolysis, kinetics, mechanism.
Variation in the root bark phenolics/sugar ratio of Douglas-fir grown in two plantations in northern Idaho
Authors: Myszewski Jennifer H , Fins Lauren , Moore James A , Rust Marc , Mika Peter G
Published: July 2002

Several studies have linked high phenolics/sugar ratios in the inner root bark tissue of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) to decreased susceptibility to Armillaria spp. While these studies have identified environmental factors that influence root chemistry, none have examined whether the phenolics/sugar ratio is genetically controlled. In this study, we investigated the effects of genetics and environment on the root bark chemistry of 20 families of 15-year-old Douglas-fir planted in two sites in northern Idaho. Only sugar concentrations varied significantly among families, but site was a significant source of variation for phenolics and the phenolics/sugar ratio. Family × site interactions were significant for the concentrations of all measured root bark compounds as well as for the phenolics/sugar ratio. Phenotypic correlations between height and the phenolics/sugar ratio and between height and sugar concentrations were not significant. However, families with superior height growth and below-average sugar concentrations could be found at both sites. Should a high phenolics/sugar ratio prove effective in selecting genotypes for resistance to Armillaria infection, these results suggest that gains could be made more efficiently by selecting for low sugar concentrations.
BEYOND TAMAKI-SATO STYLE UNFOLD/FOLD TRANSFORMATIONS FOR NORMAL LOGIC PROGRAMS
Authors: ROYCHOUDHURY ABHIK , NARAYAN KUMAR K. , RAMAKRISHNAN C. R. , RAMAKRISHNAN I. V.
Published: July 2002

Unfold/fold transformation systems for logic programs have been extensively investigated. Existing unfold/fold transformation systems for normal logic programs typically fold using a single, non-recursive clause i.e. the folding transformation is very restricted. In this paper we present a transformation system that permits folding in the presence of recursion, disjunction, as well as negation. We show that the transformations are correct with respect to various model theoretic semantics of normal logic programs including the well-founded model and stable model semantics.
DILATION METHOD AND SMOOTHING EFFECT OF THE SCHRÖDINGER EVOLUTION GROUP
Authors: HAYASHI N. , KATO K. , OZAWA T.
Published: July 2002

We reexamine the mechanism of smoothing effects of the Schrödinger evolution group in the weighted Sobolev spaces by using the generator of space-time dilations instead of Galilei transformations.
A FUNCTORIAL APPROACH TO THE C*-ALGEBRAS OF A GRAPH
Authors: SPIELBERG JACK
Published: July 2002

A functor from the category of directed trees with inclusions to the category of commutative C*-algebras with injective *-homomorphisms is constructed. This is used to define a functor from the category of directed graphs with inclusions to the category of C*-algebras with injective *-homomorphisms. The resulting C*-algebras are identified as Toeplitz graph algebras. Graph algebras are proved to have inductive limit decompositions over any family of subgraphs with union equal to the whole graph. The construction is used to prove various structural properties of graph algebras.
MULTICANONICAL SIMULATIONS OF FIVE TETRAPEPTIDE SEQUENCES IN THE CENTRAL DOMAIN OF HMW GLUTENIN
Authors: ARKIN HANDAN , YAŞAR FATİH , ÇELİK TARIK , ÇELİK SÜEDA , KÖKSEL HAMİT
Published: July 2002

The application of the multicanonical simulation method to small proteins and peptides seems to be feasible and should be undertaken. In this work, the three-dimensional structures of five common tetrapeptide sequences (QPGQ, QSGQ, YPTS, SPQQ and QPGY, in one letter code) in the repetitive central domain of HMW glutenin subunits are investigated by using the multicanonical simulation procedure. Ramachandran plots were prepared and analyzed to predict the relative occurrence probabilities of β-turn and γ-turn structures and helical states. Structural predictions of the five tetrapeptide sequences indicated the presence of high level of β-turns and considerable level of γ-turns. It was also possible to distinguish different type of turns and their occurrence probabilities.
ANALYSIS OF PREDOMINANCE OF SEXUAL REPRODUCTION AND QUADRUPLICITY OF BASES BY COMPUTER SIMULATION
Authors: DASGUPTA SUBINAY
Published: July 2002

We have presented elsewhere a model for computer simulation of a colony of individuals reproducing sexually, by meiotic parthenogenesis and by cloning. Our algorithm takes into account food and space restriction, and attacks of some diseases. Each individual is characterized by a string of L "base" units, each of which can be of four types (quaternary model) or two types (binary model). Our previous report was for the case of L = 12 (quaternary model) and L = 24 (binary model) and contained the result that the fluctuation of population was the lowest for sexual reproduction with four types of base units. The present communication reports that the same conclusion also holds for L = 10 (quaternary model) and L = 20 (binary model), and for L = 8 (quaternary model) and L = 16 (binary model). This model however, suffers from the drawback that it does not show the effect of aging. A modification of the model was attempted to remove this drawback, but the results were not encouraging.
COSMOLOGY AND HIERARCHY IN STABILIZED RANDALL-SUNDRUM MODELS
Authors: MARFATIA DANNY
Published: July 2002

We consider the cosmology and hierarchy of scales in models with immersed in a five-dimensional curved spacetime subject to radion stabilization. The universe naturally find itself in the radiation-dominated epoch when the inter-brane spacing is static and stable, independent of the form of the stabilizing potential. We recover the standard Friedmann equations without assuming a specific form for the bulk energy-momentum tensor. We address the hierarchy problem in the context of a quartic and exponential stabilizing potential, and find that in either case the presence of a negative tension brane is required and that the string scale can be as low as the electroweak scale. In the situation of self-tuning branes (corresponding to an exponential potential) where the bulk cosmological constant is set to zero, the brane tensions have hierarchical values.
MEASUREMENTS OF A SVXII PROTOTYPE LADDER USING COSMIC AND SOURCE DATA
Authors: FERNANDEZ JUAN PABLO
Published: July 2002

Results on tests conducted on real SVXII ladders using cosmic rays and beta source data are presented. These results include charge collection and signal to noise ratio.
ON ROTATING REGULAR NON-ABELIAN SOLUTIONS
Authors: VAN DER BIJ J. J. , RADU EUGEN
Published: July 2002

A general relation for the total angular momentum of a regular solution of the Einstein–Yang–Mills–Higgs equations is derived. Two different physical configurations, rotating dyons and rotating magnetic dipoles are discussed as particular cases. The issue of rotating pure Einstein–Yang–Mills regular solutions is addressed as well. Based on the results, we conjecture the absence of rotating regular solitons with a net magnetic charge.
WHAT IS THE TEMPERATURE DEPENDENCE OF THE CASIMIR FORCE BETWEEN REAL METALS?
Authors: KLIMCHITSKAYA G. L.
Published: July 2002

The situation with the temperature corrections to the Casimir force between real metals of finite conducitivity is reported. It is shown that the plasma dielectric function is well adapted to the Lifshitz formula and leads to reasonable results for real conductors. The Drude dielectric function which describes media with dissipation is found not to belong to the application range of the Lifshitz formula at nonzero temperature. For Drude metals the special modification of the zero-frequency term of this formula is suggested. The contradictory results on the subject in recent literature are analysed and explained.
POSSIBLE CHARGE AND/OR SPIN ORDERING IN THE Bi-2212, Y-123 AND La-214 PHASES
Authors: KOIKE Y. , AKOSHIMA M. , AOYAMA M. , NISHIMAKI K. , KAWAMATA T. , ADACHI T. , NOJI T. , WATANABE I. , OHIRA S. , HIGEMOTO W. , NAGAMINE K.
Published: July 2002

Our recent experimental studies on the so-called 1/8 anomaly in the Bi-2212 and Y-123 phases and also on the new anomaly in the overdoped region of the La-214 phase are reviewed. In the partially Zn-substituted Bi-2212 and Y-123 phases, we have found anomalous suppression of superconductivity (SC) at p (the hole concentration per Cu in the CuO 2 plane) ~1/8, and it has been found from the muon-spin-relaxation (μSR) measurements that the magnetic correlation between Cu spins is enhanced singularly at p~1/8. Furthermore, we have found giant suppression of SC singularly at x=0.21 in the 1% Zn-substituted single-crystals of La 2-x Sr x Cu 1-y Zn yO4 (LSCZO), and it has been found from the μSR measurements that the magnetic correlation is also enhanced at x=0.21. These results suggest that the dynamical stripe correlations of holes and spins exist in the Bi-2212 and Y-123 phases as well as in the La-214 phase and that they tend to be pinned by a small amount of Zn, leading to quasi-static stripe order and the suppression of SC at p~1/8 in the Bi-2212, Y-123, La-214 phases and also at x=0.21 in LSCZO. If this tendency is the case in a wide range of p, it is possible to understand the universal experimental results in the high-Tc cuprates that Zn is a strong scatterer in the unitarity limit and that the Zn substitution markedly suppresses SC.
THE THIRD ORDER NONLINEAR SUSCEPTIBILITY OF INTERACTING ONE-DIMENSIONAL FRENKEL EXCITONS
Authors: Ishihara H. , Amakata T.
Published: July 2002

An analytical expression of the third order nonlinear susceptibility χ(3) has been derived rigorously for a system of interacting Frenkel excitons in a one-dimensional chain of size N with the periodic boundary conditions. It has been clarified that the magnitude of interacting potential between excitons strongly influences the size dependence of χ(3) in the long wavelength approximation, which is well explained in terms of the cancellation effect between the contributions from [ground state] - [one-exciton] transitions and those from [one-exciton] - [two-exciton state] transitions.
Control of temperature dependence of exciton energies in CuI-CuBr alloy thin films grown by vacuum deposition
Authors: Tanaka I. , Sugimoto K. , Kim D. , Nishimura H. , Nakayama M.
Published: July 2002

We report the temperature dependence of exciton energies in CuI-CuBr ( CuI 1-x Br x) alloy thin films with the thickness of 50 nm grown on Al 2 O 3 substrates by vacuum deposition. From X-ray-diffraction measurements, we have confirmed that crystalline alloy thin films are preferentially oriented along the <111> crystal axis. The Z1,2-exciton energy exhibits a negative bowing as a function of the alloy composition, while the Z 3-exciton energy changes smoothly. The novel finding in the present work is a drastic change of the temperature dependence of the exciton energies in the alloy thin films. The temperature dependence in the CuI film exhibits the negative shift with the increase of temperature, while that in the CuBr film shows the positive one. We have found that the temperature dependence of the CuI 1-x Br x thin film changes from the negative shift to the positive one around the alloy composition of x=0.1. We qualitatively discuss the above finding from the aspect of electron-phonon interactions.
SIMS DEPTH PROFILING ANALYSIS OF Cu/Ta/SiO2 INTERFACIAL DIFFUSION AT DIFFERENT ANNEALING TEMPERATURE
Authors: LIU LING , GONG HAO , WANG YUE , WEE A. T. S. , LIU RONG
Published: July 2002

The interfacial reactions of Cu (60 nm )/ Ta (35 nm )/ SiO 2/ Si and Cu (500 nm )/ Ta (35 nm )/ SiO 2/ Si have been investigated in the 350°C ~ 700°C temperature range. We have found that the thickness of Cu top layer is one of the key factors to influence Ta barrier performance in the Cu/barrier/SiO 2/ Si system. SIMS depth profile spectra were obtained by using O 2+ primary ion beam with 12.5keV high voltage and a 5.0keV extraction field of the secondary ions. In the thinner (60nm) Cu system, Si has not penetrated the whole 35nm Ta layer after annealing at 600°C for 30 min under high vacuum. This indicated Ta still functions as a diffusion barrier between Cu and Si at 600°C, though Ta 5 Si 3 formed at 500°C as shown by XRD results. As a good diffusion barrier material for Cu metallization, 35nm Ta layer prevent Cu and Si inter diffusion at 650°C for at least 30 min. In the thicker Cu (500nm) system, top Cu layer changes its structural from small grain to big grain during annealing. This could suppress the grain boundary diffusion of Cu to Ta and SiO 2. 35nm Ta layer still functions as diffusion barrier between Cu and SiO 2 at the annealing temperature of 700°C.
STUDY OF THE ELECTRODYNAMIC RESPONSE OF MgB2 SINTERED PELLETS AND THIN FILMS
Authors: ANDREONE A. , DI GENNARO E. , LAMURA G. , SALLUZZO M. , LE COCHEC J. , GAUZZI A. , CANTONI C. , PARANTHAMAN M. , CERESARA S. , GIUNCHI G.
Published: July 2002

We present a number of experimental results on the temperature dependence of the magnetic penetration depth λ and on the temperature and field dependence of the microwave surface impedance Z s =R s +iX s in both pellets and thin films of MgB2 , exhibiting critical temperatures ranging between 26 and 38 K. Accurate measurements of Z s (H,T) were performed by means of a sapphire dielectrically loaded cavity operating in the microwave region (20 GHz). The study of λ(T) was carried out employing a single coil mutual inductance technique in the MHz region. An anisotropic s-wave BCS model can account for the temperature dependence experimentally observed in the penetration depth data of the best films, confirming previous reports on the conventional nature of superconductivity in diborides. On the contrary, films having a reduced value of the critical temperature and pellets show no evidence of saturation, and the experimental results strictly follow a quadratic dependence down to the lowest temperatures. We explain this behavior with the presence of metallic Mg inclusions that may locally depress the gap. The study of the surface impedance versus temperature and field shows also that the source of microwave loss can be markedly different, depending on the structural and transport properties of the samples.
NONCLASSICAL STATES EVOLVING FROM CLASSICAL STATES IN A POLARITON SYSTEM AT LOW TEMPERATURE
Authors: ZOU JIAN , SHAO BIN
Published: July 2002

We show that the photon quadrature squeezing, the phonon quadrature squeezing and the polariton quadrature squeezing can exist in a model polariton system at low temperature with the photons and the phonons initially being prepared in the coherent states and the thermal states respectively and the distributions of the photons, the phonons and the polaritons can be sub-Poissonian. We also show that all these effects strongly depend on the temperature.