bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrode Kinetics of the Ti(IV)/Ti(III) System in Water and in WaterDimethylformamide and WaterDimethyl Sulfoxide Mixed Solvents
Authors: Kišová Libuše , Šotková Šárka , Komendová Ivana
Published: July 2002

The electron transfer rate constants in the reduction of Ti4+ and oxidation of Ti3+ in water and in water DMF and water DMSO mixtures were determined by square-wave polarography and by analysis of the DC and pulse polarographic curves. The two reactions occur at different potentials due to the rapid consecutive transformation of the primary product of the electrode reaction. Thus the rate constants are no standard rate constants, and depend on the method employed. The effect of the organic co-solvent varies for both reactions as a consequence of dependence of the degree of electrode coverage on potential. Generally, the adsorbed organic substance exerts an accelerating catalytic effect.
Study of Briggs Rauscher Oscillatory Reaction in Aqueous Acetonitrile Mixed Medium
Authors: Lalitha Punchayil V. , Balasubramanian Natesan , Ramaswamy Ranganathan
Published: July 2002

The oscillatory behaviour of two new substrates namely, 2-thenoyltrifluoroacetone and cyanoacetic acid in the Briggs Rauscher (B-R) system was studied in detail employing a mixed medium: aqueous acetonitrile. The effect of acetonitrile concentration on the oscillatory behaviour is investigated. It is found that employing the aqueous organic mixed media is highly beneficial in the oscillatory study, enabling the study of water-insoluble substances.
Activity Coefficients and Gibbs Energies of Transfer of Tetraalkylammonium Dianilinetetraisothiocyanatochromates(III)
Authors: Holba Vladislav
Published: July 2002

The solubilities of tetraalkylammonium dianilinetetraisothiocyanatochromates(III) (alkyl = methyl, ethyl, 1-propyl, and 1-butyl) in water, water - methanol, water - tert-butyl alcohol and water - acetonitrile solutions were measured at 25 °C. The results were used to evaluate the activity coefficients and Gibbs energies of transfer of the saturating salts from water to the mixed systems. The Gibbs energies of transfer of the [Cr(C6H5NH2)2(NCS)4]- ion were obtained by means of known ionic transfer functions for the tetraalkylammonium ions based on the TATB assumption.
On the Asymmetrical Role of Intrinsic Defects in the Complementary/Opposing Oxide Formation/Dissolution Reactions
Authors: Hefny Mohamed M.
Published: July 2002

Rates of chemical dissolution (r) of anodic oxide films on Sb, W, Al, Ti, Zr and Hf were studied as a function of the energy of defect formation (Ef) in the respective oxide. The value of r was estimated from capacitance measurements. The relation between ln r and Ef is linear. The average value of the symmetry factor (α) for the dissolution reaction is 0.12. The deviation of α from 0.5 indicates that intrinsic defects play an asymmetrical role; in the present case their constructive action is about 7 times their destructive action.
Synthesis of Base-Modified "Abbreviated" NAD Analogues
Authors: Juricová Kristina , Smrčková Svatava , Holý Antonín
Published: July 2002

The "abbreviated" model of NAD, 1-[3-(adenin-9-yl)-2-hydroxypropyl]-3-carbamoylpyridinium chloride (VIIIa), and its 2,6-diaminopurine (VIIIb), 3-deazaadenine (VIIIc), guanine (VIIId) and cytosine (VIIIe) analogues were prepared by the Zincke reaction. The (R)-isomer of the adenine model VIIIa (compound IX) was prepared for chiroptical studies. As shown by NMR, UV and CD spectra, neither in dimethyl sulfoxide nor in water any intramolecular π-π interactions exist between the heteroaromatic systems.
An Efficient Method for Preparation of Optically Active N-Protected α-Amino Aldehydes from N-Protected α-Amino Alcohols
Authors: Souček Milan , Urban Ján
Published: July 2002

N-Protected α-amino aldehydes of high optical purity were prepared in excellent yields from corresponding α-amino alcohols by 1,1,1-tris(acetoxy)-1,1-dihydro-1,2-benzoidoxol-3(H)-one (periodinane) oxidation.
Effect of Initial Polymerization Conditions on the Structure of Ethyl Acrylate-Methacrylic Acid Copolymer Latex Particles
Authors: Šňupárek Jaromír , Bradna Pavel , Mrkvičková Libuše , Lednický František , Quadrat Otakar
Published: July 2002

Non-seeded semi-continuous emulsion copolymerizations of ethyl acrylate-methacrylic acid (85/15 wt. ratio) were carried out using various emulsifier and initiator concentrations and phase partitioning. The effect of the polymerization conditions on the particle size and morphology was investigated by means of scanning electron microscopy, light scattering and viscometry. Disintegration into smaller particles on alkali addition confirmed coagulative mechanism of the particle growth. This is distinct mainly if the colloidal stability of the polymerizing system is reduced due to lower concentration of the emulsifier and higher concentration of peroxydisulfate initiator which suppress double layer thickness of forming particles.
Composite Artificial Tendons with Hydrogel Matrix
Authors: Kolařík Jan
Published: July 2002

The brief review is concerned with synthetic model tendons consisting of water-swollen hydrogel matrix and poly(ethylene terephthalate) fibres. Texturized fibres were employed in tendon construction in order to imitate stress-strain and other mechanical properties of natural tendons. Stiffness, creep behaviour, strength, and elongation-at-break of model tendons are predetermined by those of incorporated fibre bundles. Thus, by varying the fibre volume fraction, it is possible to achieve mechanical properties required for various types of tendon prostheses.
Alkaloids from Papaver setigerum DC.
Authors: Slavík Jiří , Slavíková Leonora
Published: July 2002

Two new benzylisoquinoline alkaloids of the papaverine type, setigerine (racemic α-methoxypapaverine, 1b) and setigeridine (1c), were isolated from Papaver setigerum DC. as the minor constituents. Their structures were established by spectral data and X-ray crystallographic analysis. Papaverine (1a) was isolated as the major alkaloid of the plant (0.05 wt.%) besides of less amounts of morphine, codeine and rhoeadine. In a low yield, protopine, cryptopine, thebaine, rhoeagenine, and N-methylthebainium (as iodide) were obtained and small quantities of laudanosine, stylopine, isoboldine, scoulerine, papaverrubine A, B, C, D and E, coptisine, corytuberine, and magnoflorine were identified by thin layer chromatography.
Polyhedral Azaborane Chemistry: NMR Parameters for the Unique Eight-Boron Polyhedral Species [(C2H5NH2)B8H11NHC2H5]
Authors: MacKinnon Peter , Fontaine Xavier L. R. , Kennedy John D. , Salter Paul A.
Published: July 2002

Boron (11B) and hydrogen (1H) NMR parameters have been measured for the unique polyhedral azaborane species [(NH2Et)B8H11NHEt)] using single- and double-resonance experiments and two-dimensional shift-correlation methods. Comparison with the NMR properties of other eight-boron species, in particular arachno-[B8H12(PMe2Ph)], suggests that cluster of [(NH2Et)B8H11NHEt] may be better regarded as being of hypho character, rather than of arachno character as previously supposed.
Hydrophobic Ferrocene Derivatives as Potential Standards in Electrochemistry
Authors: Podlaha Jaroslav , Štěpnička Petr , Gyepes Róbert , Mareček Vladimír , Lhotský Alexander , Polášek Miroslav , Kubišta Jiří , Nejezchleba Martin
Published: July 2002

Ferrocene (FcH) derivatives monosubstituted by palmitoyl (1), hexadecyl (2), 1-adamantoyl (3) or 1-adamantylmethyl (4) groups were sythesized and characterized by NMR, mass and 57Fe Mossbauer spectroscopy. The structure of 1-adamantoylferrocene was determined by single-crystal X-ray diffraction. Cyclic voltammetry on gold and glass-like carbon electrodes demonstrated that the compounds can serve as electrochemical standards for special cases since their ferrocene/ferricinium redox potential remains stable and reversible, while the properties such as solubility, diffusion coefficients and surface tension are strongly solvent-dependent.
Effect of 2-Alkylthio-4-pyridinecarbothiamides on Photosynthetic Electron Transport in Spinach Chloroplasts
Authors: Kráľová Katarína , Šeršeň František , Klimešová Věra , Waisser Karel
Published: July 2002

2-Alkylthio-4-pyridinecarbothiamides (1) inhibit photosynthetic electron transport in spinach chloroplasts. The dependence of photosynthesis-inhibiting activity upon the lipophilicity of 2-alkylthio substituent shows quasi-parabolic course with maximum effectiveness at 2-octyl derivative. The site of action of 1 is the intermediate D+, corresponding to tyrosine radical, which is situated in D2 protein on the donor side of photosystem 2.
Synthesis of 4-Alkyl- or 4-Phenyl-7-methyl-1,2-dihydro-7H-imidazo[1,2,3-cd]purine-6,8-diones
Authors: Šimo Ondrej , Rybár Alfonz , Alföldi Juraj
Published: July 2002

New 4-alkyl- or 4-phenyl-7-methyl-1,2-dihydro-7H-imidazo[1,2,3-cd]purine-6,8-diones 1 were obtained by intramolecular alkylation of 8-alkyl- or 8-phenyl-9-(2-mesyloxyethyl)-1-methyl-9H-purine-2,6(1H,3H)-diones 5. The necessary compounds 5 were prepared from 6-[(2-hydroxyethyl)- amino]-3-methyl-5-nitrosopyrimidine-2,4(1H,3H)-dione (2), which was hydrogenated to 5-amino-6-[(2-hydroxyethyl)amino]-3-methyl derivative 3; consecutive reactions of the latter with an orthocarboxylate and mesyl chloride afforded 8-alkyl- or 8-phenyl-9-(2-hydroxyethyl)-1-methyl-9H-purine- 2,6(1H,3H)-diones 4 and compounds 5, respectively.
119Sn, 15N, 13C, and 1H NMR Study of the Intramolecular Sn-N Donor-Acceptor Interaction in [2-(Dimethylaminomethyl)phenyl]stannanes
Authors: Růžička Aleš , Pejchal Vladimír , Holeček Jaroslav , Lyčka Antonín , Jacob Klaus
Published: July 2002

119Sn, 15N, 13C, and 1H NMR spectra were studied for [2-(dimethylaminomethyl)phenyl]stannanes, R1R2R3R4Sn or R1R2R24Sn, where R1, R2, and R3 are 1-butyl, Cl or Br, the same or different, and R4 is 2-(dimethylaminomethyl)phenyl. The occurrence of intramolecular interaction between the nitrogen and tin atoms was demonstrated based on changes in the characteristic values of the NMR parameters of these nuclides (δ(15N), δ(119Sn), J(119Sn,15N), and their interrelations, as well as on the relatively high values of the coupling constants 3J(119Sn,13C(CH2)).
Bent Cyclopenta-2,4-dienylideneketene: Spectroscopic and ab initio Study of Reactive Intermediate
Authors: Radziszewski Juliusz G. , Kaszynski Piotr , Friderichsen Anders , Abildgaard Jens
Published: July 2002

Results of an experimental and theoretical study of cyclopenta-2,4-dienylideneketene (3), a highly unstable reactive intermediate, are reported. The ketene was prepared, under matrix isolation conditions at 4.2 or 10 K, by laser photocarbonylation of 1,2-didehydrobenzene (1) photogenerated earlier from phthalic anhydride (2). FTIR polarization measurements performed on partially photooriented samples of 3 immobilized in solid neon or argon provide infrared transition moment directions for most of the observed vibrations. Experimental results confirm that the ketene is bent, as predicted by ab initio calculations. Utilizing two isotopically modified 3, 3b and 3c, on the basis of the infrared absorption spectrum alone, we have analyzed and assigned its vibrations in a way, which leaves no doubt about the bent ketene structure. This work was motivated by a long standing confusion surrounding the assignments of the vibrations in 1,2-didehydrobenzene (1), especially of its "triple" bond stretch.
Methyl (Z)-2-[(Benzyloxycarbonyl)amino]-3-dimethyl- aminopropenoate in the Synthesis of Heterocyclic Systems. Synthesis of (Benzyloxycarbonyl)amino Substituted Fused Pyrimidinones
Authors: Toplak Renata , Svete Jurij , Golič Grdadolnik Simona , Stanovnik Branko
Published: July 2002

Methyl (Z)-2-[(benzyloxycarbonyl)amino]-3-dimethylaminopropenoate (1) was used as a reagent for preparation of 3-[(benzyloxycarbonyl)amino] substituted 4H-pyrido[1,2-a]pyrimidin-4-ones 17-21, 4H-pyrimido[1,2-b]pyridazin-4-ones 22 and 23, 5H-[1,2,4]triazolo[2,3-a]- pyrimidin-5-one 24, 5H-thiazolo[3,2-a]pyrimidin-5-one 25, and 4H-pyrazino[1,2-a]pyrimidin-4-one 26. Removal of the benzyloxycarbonyl group by catalytical transfer hydrogenation with Pd/C in the presence of cyclohexene is selective to give 3-amino-4H-pyrido[1,2-a]- pyrimidin-4-ones 27-30 in 85-92% yields, or with hydrogen bromide in acetic acid to give 3-amino-4H-pyrimido[1,2-b]pyridazin-4-one (31) and 6-amino-5H-thiazolo[3,2-a]pyrimidin-5-one (32) in 80% yields.
Intramolecular N-Acyliminium Ion-Olefin Cyclization in the Synthesis of Optically Pure Isoquinoline Derivatives: Control of Stereochemistry and Application to Synthesis of Morphine Alkaloids
Authors: Bottari Patricia , Endoma Mary Ann A. , Hudlický Tomáš , Ghiviriga Ion , Abboud Khalil A.
Published: July 2002

The 3-[2-(cyclohex-1-eneyl)ethyl]-[1,3]oxazoline-2,4-dione derivatives 9, 14 and 16 were subjected to hydride reduction followed by acid-catalyzed olefin-N-acyliminium ion cyclization to afford a series of perhydroisoquinolines 10, 11a, 11b, 19a-19c, 20a, 20b and 21. A mechanism was proposed that accounts for the observed stereoselectivity of the cyclization reactions based on the neighboring group participation by a benzoate group.
Synthesis of 2-Substituted-6,7-dimethoxy- and 6,7,8-Trimethoxy-3-hydroxyquinolin-4(1H)-ones
Authors: Hradil Pavel , Vaněček Jan , Hlaváč Jan , Ševčík Juraj
Published: July 2002

Acetonyl and phenacyl esters of 4,5-dimethoxy- and 3,4,5-trimethoxyanthranilic acids 3 were prepared by reduction of corresponding nitro derivatives 2. Acetonyl 4,5-dimethoxyanthranilate (3a) was prepared by reaction of 4,5-dimethoxyanthranilic acid and chloroacetone. Cyclization of these acetonyl and phenacyl esters in polyphosphoric acid provided the corresponding 2-substituted-6,7-dimethoxy- and 6,7,8-trimethoxy-3-hydroxyquinolin-4(1H)-ones 4. A new method of the thermal cyclization is also described. The structure of the prepared compounds was confirmed by 1H NMR spectroscopy.
Metal Ion-Binding Properties of the Nucleotide Analogue 1-[2-(Phosphonomethoxy)ethyl]cytosine (PMEC) in Aqueous Solution
Authors: Blindauer Claudia A. , Holý Antonín , Sigel Helmut
Published: July 2002

The acidity constants of the twofold protonated nucleotide analogue 1-[2-(phosphonomethoxy)ethyl]cytosine, H2(PMEC)±, as well as the stability constants of the M(H;PMEC)+ and M(PMEC) complexes with the metal ions M2+ = Mg2+, Ca2+, Sr2+, Ba2+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, and Cd2+ have been determined by potentiometric pH titrations in aqueous solution at I = 0.1 M (NaNO3) and 25 °C. Comparison with previous results for the nucleobase-free compound (phosphonomethoxy)ethane, PME, and the parent nucleotides cytidine 5'-monophosphate (CMP2-) and 2'-deoxycytidine 5'-monophosphate (dCMP2-) shows that the metal ion-binding properties of PMEC2- resemble closely those of PME2-: This means, the primary binding site is the phosphonate group and with all of the metal ions studied, 5-membered chelates involving the ether oxygen of the -CH2-O-CH2-PO32- chain are formed. The position of the isomeric equilibria between these chelates and the "open" complexes, -PO32-/M2+ is calculated; the degree of formation of the chelates is identical within the error limits for the M(PME) and M(PMEC) systems. Hence, like in M(CMP) and M(dCMP) no interaction occurs with the cytosine residue in the M(PMEC) complexes. However, the monoprotonated M(H;PMEC)+ as well as the M(H;CMP)+ and M(dCMP)+ species carry the metal ion predominantly at the nucleobase, while the proton is at the phosph(on)ate group. The coordinating properties of PMEC2- and CMP2- or dCMP2- differ thus only with respect to the possible formation of the 5-membered chelates involving the ether oxygen in M(PMEC) species, a possibility which does not exist in the complexes of the parent nucleotides. Possible reasons why PMEC is devoid of a significant antiviral activity are shortly discussed.
Transient Kinetic and Thermodynamic Behaviour of Langmuir Adsorption in a Flow System
Authors: Pekař Miloslav , Koubek Josef
Published: July 2002

Various kinetic pathways to the adsorption equilibrium in an isothermal differential bed of adsorbent are illustrated on several examples. Discussion is based on the computed transient responses of adsorption rate and distance from adsorption equilibrium to the start of adsorptive feed. It is shown that adsorption behaviour in flow system may not be smooth and very steep changes on the rate responses may appear. Even the simple reaction need not approach equilibrium smoothly but at a jump. The approach assuming "closeness to the equilibrium" should be used very carefully, in this case.
Infrared, 119Sn, 13C and 1H NMR, 119Sn and 13C CP/MAS NMR and Mössbauer Spectral Study of Some Tributylstannyl Citrates and Propane-1,2,3-tricarboxylates
Authors: Holeček Jaroslav , Lyčka Antonín , Micák David , Nagy László , Vankó György , Brus Jiří , Raj S. Shanmuga Sundara , Fun Hoong Kun , ng Seik Weng
Published: July 2002

Six tributylstannyl citrates and three tributylstannyl propane-1,2,3-tricarboxylates of the formula R1C(CH2COOR2)(COOR3)(CH2COOR4) (R1 = OH or H, R2, R3, R4 = H, Bu3Sn, C6H11NH3, (C6H11)2NH2 or (CH2)5NH2) have been synthesised, and their solution and solid-state structures studied by infrared, 1H, 13C and 119Sn NMR, 13C and 119Sn CP/MAS NMR and 119Sn Mössbauer spectroscopies. In non-coordinating solvents, the compounds exist as isolated molecules or ionic-pairs with their tin atoms in pseudotetrahedral environments. In coordinating solvents, the tin atoms in the compounds are five-coordinate owing to the participation of the solvent in bonding; and their trans-trigonal bipyramidal coordination spheres consist of the ipso-carbon atoms of the butyl substituents in equatorial plane, and the solvent molecule and the oxygen atom of the monodentate carboxyl group in axial positions. A part of tributylstannyl groups together with some bidentate bridging carboxylate groups form polymeric chains in the solid state of citrates and propane-1,2,3-tricarboxylates. Also dioxastanna-rings with the participation α-hydroxycarboxylate fragments and one of the tributylstannyl groups occur probably in some citrates in the solid state. The spectroscopic assignment for the citrate has been confirmed by crystal structure analysis.
Multivariate Regression with Substituent Shift Increments. III. 2,5-Disubstituted Furans
Authors: Holík Miroslav , Friedl Zdeněk , Marchalín Štefan
Published: July 2002

Six series of 2-X-5-Y-substituted furans were used for multivariate regression of 13C NMR chemical shifts with four substituent shift increments (SSI). Some of these series were measured in CDCl3 and DMSO-d6 on different spectrometers to exclude possible sources of deviation from the general trends. Program ASSIGN was written for visual and numerical estimation of correct assignment of 13C NMR spectra in the series of derivatives. Multivariate regression proved that the corresponding position in benzenes and furans are not affected by the substituents in the same way: in 2-X-5-Y-substituted furans, the "ortho" position requires correction for the different bond order, the "meta" 13C chemical shift is probably affected by change in diamagnetic contribution of the Y group, and "para" position behaves like another "ortho" position in the molecule.
A Covalently Bound Template in the Regioselective Synthesis of Bis(tetraazacrown)s
Authors: Chadim Martin , Buděšínský Miloš , Hodačová Jana , Závada Jiří
Published: July 2002

The two-carbon core in the tricyclic bis(aminal)s arising by condensation of linear tetramines with biacetyl serves as a template in the regioselective alkylation with 1,2,4,5-tetrakis(bromomethyl)benzene.
Sterically Crowded Heterocycles. XII. Atropisomerism of (1-Aryl-3,5-diphenyl-1H-pyrrol-2-yl)(phenyl)methanones
Authors: Klvaňa Robert , Pohl Radek , Pawlas Jan , Čejka Jan , Dvořáková Hana , Hrabal Richard , Böhm Stanislav , Kratochvíl Bohumil , Kuthan Josef
Published: July 2002

Some 1-(2-substituted phenyl)- and 1-(1-naphthyl)-2,4,6-triphenylpyridinium perchlorates were treated with potassium hexacyano ferrate(III)-potassium hydroxide reagent to give the title pyrroles. Restricted rotation around the C-N bond in the products is demonstrated by NMR experiments with homochiral shift reagents, by semiempirical PM3 calculations as well as using their atropodiastereoselective and enantioselective transformations. Racemisation barriers for the (R)-2-(N-methyl-N-phenylcarbamoyl) derivative were estimated from NMR and polarimetric measurements.
Electrochemical Reduction of Allyl Ethers in the Presence of Nickel Complexes: A Review of Synthetic Applications
Authors: Olivero Sandra , Franco Delphine , Clinet Jean-Claude , Duñach Elisabet
Published: July 2002

This review deals with the electrochemical reactivity of a family of organic compounds, namely allyl ether derivatives, in the presence of various catalytic systems. Essentially, nickel complexes associated with various ligands have been described for such reactions. The electrochemical reduction of allyl aryl ethers has been reported to be very dependent on the nature of the catalytic system. Ni(II) complexes with 2,2'-bipyridine ligands selectively catalyze the cleavage of the O-C(allyl) bond to afford the corresponding alcohol or phenol derivatives in good yields. The related ortho-halogenated allyl ether substrates, in the presence of Ni(II) catalysts with cyclam-type macrocyclic ligands undergo intramolecular cyclizations. The nature of the ligand on nickel strongly influences the reactivity and the chemoselectivity of these processes. A review with 62 references.
A Novel Synthesis of [1]Benzothieno[3,2-b][1]benzofuran
Authors: Černovská Kateřina , Nič Miloslav , Pihera Pavel , Svoboda Jiří
Published: July 2002

A new synthesis of the title compound based on the formation of the furan ring in the key step was elaborated. Methyl 2-methoxy[1]benzothieno[3,2-b][1]benzofuran-7-carboxylate (15) was prepared by this methodology as a new type of a core for liquid crystal synthesis.
Dental Amalgam, an Alternative Electrode Material for Voltammetric Analyses of Pollutants
Authors: Mikkelsen Øyvind , Schrøder Knut H. , Aarhaug Thor Anders
Published: July 2002

Liquid mercury and liquid mercury amalgams are superior electrode materials in voltammetry for analytical purposes. This is mainly due to the high overvoltage to hydrogen, which enables the detection of heavy metals with high negative half-wave potentials. Because of the toxicity of mercury and liquid mercury compounds, their use is increasingly restricted, and cannot be included in voltammetric devices for field and on-line applications. Authors have studied properties of dental amalgam as an electrode material in voltammetry. The results show that dental amalgam acts similarly to a silver electrode. Also, it has a high hydrogen overvoltage, allowing it to be used, e.g., for detection of zinc. In addition, due to special properties of dental amalgam compared with mercury itself, it is not toxic. New in this paper is the determination of nickel and cobalt on the dental amalgam electrode using adsorptive cathodic stripping voltammetry (AdCSV). Also, some new data on detection of zinc, cadmium, lead and thallium are presented. The results show that this electrode can be used over a long period of time without any maintenance, which is important for on-line analyses of pollutants in soil and groundwater.
Novel Systems for Selective Cation Detection: Application of a Lipophilic Carborane Anion in Polymeric Ion-Selective Electrodes
Authors: Krondak Martin , Volf Radko , Král Vladimír
Published: July 2002

Selectivity and sensitivity of PVC membrane electrode are dramatically influenced not only by the specific receptor, but also, mainly for neutral ionophores, by additional lipophilic co-receptor. For cation detection, tetraphenylborate derivatives have been commonly used. Here, we describe novel systems based on conjunction of the classic cation receptors and a highly lipophilic cobalticarborane anionic species. The superiority of this novel co-receptor is demonstrated by application of dibenzo-18-crown-6 and dicyclohexano-18-crown-6 as ionophores in conjunction with the classic lipophilic additive and the novel additive cobalticarborane. The presented data show much higher efficiency which makes this additive co-receptor ideal for cation detection and development of novel sensors.
Accidents and resulting injuries in premobile infants: data from the ALSPAC study
Authors: Warrington S A , Wright C M , Team ALSPAC Study
Published: July 2002

BACKGROUND AND AIMS

Little is known about injuries resulting from accidents in premobile infants. We aimed to describe the pattern of minor accidents in infants and their resulting injuries.

METHODS

The ALSPAC study collected data in successive postal questionnaires. At 6 months of age, parents were asked to describe any accident since birth. The type of fall, distance fallen, resulting injury, and help sought were independently coded. Burns were similarly coded.

RESULTS

A total of 11 466 responses were available. In 2554 children, 3357 falls were reported; 53% fell from beds or settees and 12% fell from arms or while being carried. Only 14% reported visible injury, of which 56% were bruises; 97% of injuries specified involved the head. Only 21 falls (<1%) resulted in concussion or fracture. A burn or scald occurred in 172 cases (1.5%). The main causes of scalds were hot drinks and water, with contact burns caused by radiators, cookers, and hot food.

CONCLUSIONS

Falls in young infants are common while burns are rare. Injuries from falls are infrequent, predominantly trivial, and almost entirely confined to the head. Falls from beds and settees did not result in skull fractures. Serious injury was the result of complex accidents.
Nasal and intrapulmonary haemorrhage in sudden infant death syndrome
Authors: Becroft D M O , Thompson J M D , Mitchell E A
Published: July 2002

BACKGROUND

Fresh intrapulmonary and oronasal haemorrhages in cases of sudden infant death syndrome (SIDS) might be markers for accidental or intentional smothering inappropriately diagnosed as SIDS.

AIM

To compare the incidence, epidemiological association, and inter-relation of nasal haemorrhage, intrapulmonary haemorrhage, and intrathoracic petechiae in infant deaths certified as SIDS.

METHODS

In SIDS cases from a large nationwide case–control study, a wide range of variables were compared in cases with and without reported nasal haemorrhage and, in a subgroup of cases, in those with and without pathologically significant intrapulmonary haemorrhage.

RESULTS

Nasal haemorrhage was reported in 60 of 385 cases (15%) whose parents were interviewed. Pathologically significant intra-alveolar pulmonary haemorrhage was found in 47% of 115 cases studied, but was severe in only 7%. Infants with nasal haemorrhage had more haemorrhage into alveoli and air passages than age matched cases without nasal haemorrhage. In multivariate analysis, nasal haemorrhage was associated with younger infant age, bed sharing, and the infant being placed non-prone to sleep. Intrapulmonary haemorrhage was associated with the same three factors in univariate analysis, but in multivariate analysis only younger infant age remained statistically significant. There was no significant association between nasal or intra-alveolar haemorrhages and intrathoracic petechiae.

CONCLUSIONS

Nasal and intrapulmonary haemorrhages have common associations not shared with intrathoracic petechiae. Smothering is a possible common factor, although is unlikely to be the cause in most cases presenting as SIDS.
What do under 15 year old schoolboy rugby union players think about protective headgear?
Authors: Finch C F , McIntosh A S , McCrory P
Published: July 2002

Objectives—When protective headgear is designed, the attitudes of the intended users needs to be taken into account, as well as safety performance criteria. The aim of this study was therefore to determine the attitudes of schoolboy rugby union players towards protective headgear.

Methods—A survey of 140 rugby union players (82.4% response rate) from 10 randomly selected school teams in metropolitan Sydney was conducted at the end of the 1999 playing season. All players were aged 14–16 years. All teams had participated in a trial of headgear during the 1999 season in which six of the teams had been assigned to a headgear trial arm and four teams to a control arm. Players completed a self report questionnaire during a supervised session at school. The questionnaire collected information on recent head injuries, use of protective equipment, and attitudes towards headgear.

Results—Some form of protective equipment was always worn by 76.1% of players: 93.6% reported using a mouthguard and 79.3% a helmet/headgear during the 1999 season. The two most important reasons for wearing headgear were related to safety concerns. Players with no recent head/neck injury were more likely to report that they felt safer when wearing headgear (p<0.001) and less likely to cite a previous injury as a motivating factor for wearing headgear (p<0.001) than those who had sustained a recent head/neck injury. Of the players who wore headgear during the 1999 season, 67% said that they played more confidently when they wore headgear, but 63% said that their head was hotter. Few players reported that their head was uncomfortable (15%) or that it was hard to communicate (3%) when they wore headgear. The main reasons for not wearing headgear were related to its design features: uncomfortable (61%) and it was hot (57%).

Conclusions—The primary reason cited by players for wearing headgear is safety. Receiving an injury would also motivate non-wearers to wear headgear. Players report that they are more confident and able to tackle harder if they wear headgear, suggesting that a belief in its protective capabilities may influence behaviour. These attitudes need to be addressed in the design of effective headgear as well as in strategies to promote its use.
The relative stress on the Achilles tendon during ambulation in an ankle immobiliser: implications for rehabilitation after Achilles tendon repair
Authors: Akizuki K H , Gartman E J , Nisonson B , Ben-Avi S , McHugh M P
Published: July 2002

Background—After Achilles tendon repair, immediate weightbearing and immobilisation closer to neutral plantarflexion are thought to limit atrophy and stiffness, but may place deleterious stress on the repair.

Objectives—To estimate the relative stress on the Achilles tendon during weightbearing with immobilisation in varying degrees of plantarflexion.

Methods—Electromyographic (EMG) activity from the plantarflexors was recorded during walking in 10 subjects (six men, four women) without ankle pathology. Four walking conditions were examined: (a) normal walking; (b) immobilised (cam-walker) in neutral plantarflexion; (c) immobilised with a 0.5 inch heel lift; (d) immobilised with a 1 inch heel lift. EMG activity relative to plantarflexor torque was determined for each subject during isometric contractions at 25%, 50%, 75%, and 100% of maximal voluntary contraction (MVC). EMG activity during walking was calculated as a percentage of MVC based on the EMG-torque relation during graded isometric contractions.

Results—During normal walking, the plantarflexor torque was estimated to be 30 (12)% (mean (SD)) of MVC, compared with 21 (15)% MVC for immobilisation in neutral (p<0.05), 17 (15)% MVC with the addition of a 0.5 inch heel lift (p<0.01), and 12 (12)% MVC with the addition of a 1 inch heel lift (p<0.01). The 1 inch heel lift resulted in less than 10° plantarflexion in all subjects.

Conclusions—When the ankle is immobilised, stress on the Achilles tendon is determined by the degree of plantarflexion and the contractile activity of the plantarflexors. In the immobilised ankle, the addition of a 1 inch heel lift was sufficient to minimise plantarflexor activity during walking.
Influence of preseason training, fitness, and existing injury on subsequent rugby injury
Authors: Lee A J , Garraway W M , Arneil D W
Published: July 2002

Objectives—To examine the influence of preseason fitness, existing injury, and preseason rugby training on subsequent injury.

Methods—Players were eligible for the survey if they were a member of a Scottish Rugby Union (SRU) affiliated rugby club in the Border Reivers District of the SRU during the 1997–1998 season. A total of 803 (84%) players from 22 (88%) participating clubs provided details of rugby training, injuries sustained, and physical activity undertaken during the 16 week summer period (26 April to 16 August 1997) and their perceived fitness before the start of the season. Observers at participating clubs reported all injury episodes occurring to club players throughout the 1997–1998 season.

Results—One fifth of players did not attend any rugby training during the 16 week summer period; the remainder attended a median of 14 sessions. Throughout the 1997–1998 season, 675 injury episodes occurred to 423 (53%) players during training or in matches. After adjustment for whether players held a professional contract or were amateurs, Cox regression showed a 3.9% relative increase (95% confidence interval (CI) 1.9 to 5.9%) in the risk of injury over the season for each additional preseason training week attended, and a 61% relative increase (95% CI 32 to 97%) for those players who had been injured or were carrying an injury at the end of the previous season.

Conclusions—Injury risk is more likely to be related to rugby training (type of activities undertaken in rugby training, or personalities and characteristics of players undertaking training more frequently) than to overall player fitness. Players who were injured at the end of the previous season were more likely to be injured in the following season. This may be because they do not allow previous injuries to heal sufficiently before returning to the game, or the intensity of their participation may increase their risk of injury.
The impact of face shield use on concussions in ice hockey: a multivariate analysis
Authors: Benson B W , Rose M S , Meeuwisse W H
Published: July 2002

Objective: To identify specific risk factors for concussion severity among ice hockey players wearing full face shields compared with half face shields (visors).

Methods: A prospective cohort study was conducted during one varsity hockey season (1997–1998) with 642 male ice hockey players (median age 22 years) from 22 teams participating in the Canadian Inter-University Athletics Union. Half of the teams wore full face shields, and half wore half shields (visors) for every practice and game throughout the season. Team therapists and doctors recorded on structured forms daily injury, participation, and information on face shield use for each athlete. The main outcome measure was any traumatic brain injury requiring assessment or treatment by a team therapist or doctor, categorised by time lost from subsequent participation and compared by type of face shield worn.

Results: Players who wore half face shields missed significantly more practices and games per concussion (2.4 times) than players who wore full face shields (4.07 sessions (95% confidence interval (CI) 3.48 to 4.74)v1.71 sessions (95% CI 1.32 to 2.18) respectively). Significantly more playing time was lost by players wearing half shields during practices and games, and did not depend on whether the athletes were forwards or defence, rookies or veterans, or whether the concussions were new or recurrent. In addition, players who wore half face shields and no mouthguards at the time of concussion missed significantly more playing time (5.57 sessions per concussion; 95% CI 4.40 to 6.95) than players who wore half shields and mouthguards (2.76 sessions per concussion; 95% CI 2.14 to 3.55). Players who wore full face shields and mouthguards at the time of concussion lost no playing time compared with 1.80 sessions lost per concussion (95% CI 1.38 to 2.34) for players wearing full face shields and no mouthguards.

Conclusions: The use of a full face shield compared with half face shield by intercollegiate ice hockey players significantly reduced the playing time lost because of concussion, suggesting that concussion severity may be reduced by the use of a full face shield.
Why some Jehovah's Witnesses accept blood and conscientiously reject official Watchtower Society blood policy
Authors: Elder Lee
Published: July 2002

In their responses to Dr Osamu Muramoto (hereafter Muramoto) Watchtower Society (hereafter WTS) spokesmen David Malyon and Donald Ridley (hereafter Malyon and Ridley),1–3deny many of the criticisms levelled against the WTS by Muramoto.4–6In this paper I argue as a Jehovah's Witness (hereafter JW) and on behalf of the members of AJWRB that there is no biblical basis for the WTS's partial ban on blood and that this dissenting theological view should be made clear to all JW patients who reject blood on religious grounds. Such patients should be guaranteed confidentiality should they accept whole blood or components that are banned by the WTS. I argue against Malyon's and Ridley's claim that WTS policy allows freedom of conscience to individual JWs and that it is non-coercive and non-punitive in dealing with conscientious dissent and I challenge the notion that there is monolithic support of the WTS blood policy among those who identify themselves as JWs and carry the WTS “advance directive”.
Localisation of a gene for an autosomal recessive syndrome of macrocephaly, multiple epiphyseal dysplasia, and distinctive facies to chromosome 15q26
Authors: Bayoumi Riad , Saar Kathrin , Lee Young-Ae , Nürnberg Gudrun , Reis André , Nur-E-Kamal Mohammed , Al-Gazali Lihadh I
Published: July 2002

BACKGROUND

We have previously described an autosomal recessive syndrome of macrocephaly, multiple epiphyseal dysplasia (MED), and distinctive facies in a large, extended Omani family. The MED observed seems to be part of a larger malformation syndrome, since both craniofacial and central nervous system changes were present in the family. We performed a whole genome scan in this family in order to identify the gene locus for this malformation syndrome.

METHODS AND RESULTS

Using homozygosity mapping, we show linkage to the telomeric region of the long arm of chromosome 15. The position of both the disease gene and the principal glycoprotein, chondroitin sulphate proteoglycan (aggrecan, AGC1) on chromosome 15q26, suggested that the aggrecan gene is a candidate for the disease in this family. However, three of the four affected children were heterozygous for a polymorphism at position 831 of the coding sequence ofAGC1, providing strong evidence against its involvement.

CONCLUSION

We have identified a gene locus for a recessive syndrome of macrocephaly, MED, and distinctive facies in a large Omani family. Aggrecan located on chromosome 15q26, within the critical region determined for this syndrome in this family, was excluded as a candidate gene.
Respiratory health surveillance in a toluene di-isocyanate production unit, 1967–97: clinical observations and lung function analyses
Authors: Ott M Gerald , Klees Julia E , Poche Sandy L
Published: July 2002

OBJECTIVES

To characterise irritant and allergic airway responses and assess changes in forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) relative to exposure to toluene di-isocyanate (TDI).

METHODS

Employees (n=313) ever assigned to a TDI production unit for ⩾3 months (1967–92) were identified from personnel records along with 158 frequency matched referents without known exposure to TDI. Reports made during visits to the occupational clinic of incidents related to exposure to TDI and annual periodic examination results (questionnaire, physical findings, and spirometry) were abstracted and assessed relative to industrial hygiene estimates of exposure to TDI.

RESULTS

Mean 8 hour time weighted average estimates of TDI concentrations ranged from 9.9 ppb in jobs with potentially high exposure during the early years of plant operations to 0.5 ppb in jobs with potentially low exposure in more recent years. The corresponding rates of visits to the clinic due to incidents of exposure to TDI (including both irritant and allergic airway responses) declined from 20.5 to 1.0 visits per 100 years of employment at the unit. The annual incidence of asthma induced by TDI declined from 1.8% before 1980 to 0.7% afterwards. Neither cross sectional nor longitudinal analyses of FVC and FEV1showed significant dose-response findings relative to exposure to TDI across the total exposed population. Among cases of occupational asthma there was an apparent initial decline in FEV1within 2 years of first reporting symptoms, but not an accelerated rate of decline in follow up tests from 4–30 years after induction of asthma.

CONCLUSIONS

Occurrences of both asthma induced by TDI and irritant airway responses due to exposure to TDI were found in this cohort, but there was no relation between cumulative exposure to TDI and irreversible airflow obstruction as assessed by spirometry.
Isocyanate exposure and occupational asthma: a case-referent study
Authors: Meredith S K , Bugler J , Clark R L
Published: July 2002

OBJECTIVE

To examine the quantitative relation between exposure to isocyanates and occupational asthma, and to explore the role of atopy and smoking in occurrence of the disease.

METHOD

A case-referent study was undertaken of cases from two manufacturing companies (A and B) from which referents without disease could be selected and reliable exposure measurements were available. In company A, 27 cases mainly attributed to toluene diisocyanate (TDI) were matched to 51 referents on work area, start and duration of employment, sex, and age. Exposures were estimated from existing measurements by job category. In company B there were seven cases attributed to 4,4′-diphenylmethane diisocyanate (MDI) in two areas of the plant; 12 non-cases from the same areas were used as referents. Personal exposure measurements were available for all cases and 11 referents.

RESULTS

No difference in peak exposures between cases and referents was found in either plant; but in both, time weighted average (TWA) exposures at the time of onset of asthma were higher for cases. In A, the mean TWA exposure for cases was 1.5 (95% confidence interval (95% CI) 1.2 to 1.8) ppb compared with 1.2 (1.0 to 1.4) ppb for referents. From a matched analysis, the odds ratio (OR) associated with 8 hour TWA exposure to isocyanates greater than 1.125 ppb (the median concentration for the referent group) was 3.2 (95% CI 0.96 to 10.6; p=0.06). Occupational asthma was associated with a pre-employment history of atopic illness (OR 3.5, p=0.04) and, less strongly, with smoking (OR 2.1, p=0.14). In B, small numbers limited analysis, but three of seven cases had at least one TWA exposure measurement greater than 5 ppb compared with one of 11 referents (OR 7.5, p=0.09).

CONCLUSION

Asthma can occur at low concentrations of isocyanates, but even at low concentrations, the higher the exposure the greater the risk. By contrast with other studies, smoking and atopy seemed to increase the odds of occupational asthma due to isocyanates, but did not affect the estimate of risk associated with exposure.
Requirements for occupational medicine training in Europe: a Delphi study
Authors: Macdonald E B , Ritchie K A , Murray K J , Gilmour W H
Published: July 2002

OBJECTIVES

To identify the common core competencies required for occupational physicians in Europe.

METHOD

A modified Delphi survey was conducted among members of the European Association of Schools of Occupational Medicine (EASOM), the Occupational Medicine Section of the Union of European Medical Specialities (UEMS), and of the European Network of Societies of Occupational Physicians (ENSOP). An initial questionnaire based on the training syllabus of the United Kingdom Faculty of Occupational Medicine was circulated and respondents were asked to rate the importance of each item. The results were discussed at a conference on the subject of competencies. A further questionnaire was developed and circulated which asked respondents to rank items within each section.

RESULTS

There was a 74% response in the first round and an 80% response in the second. Respondents' ratings from most important to least important were; occupational hazards to health, research methods, health promotion, occupational health law and ethics, communications, assessment of disability, environmental medicine, and management. In the second round, among those topics ranked most highly were; hazards to health and the illnesses which they cause, control of risks, and diagnoses of work related ill health. Topics such as principles of occupational safety and selection of personal protection equipment were of least importance. Although the assessment of fitness was regarded as important, monitoring and advising on sickness absence were not highly rated. Management competency was regarded as of low importance.

CONCLUSION

This survey identified that respondents had traditional disease focused views of the competencies required of occupational physicians and that competencies were lagging behind the evolving definition of occupational health.
Work correlates of back problems and activity restriction due to musculoskeletal disorders in the Canadian national population health survey (NPHS) 1994–5 data
Authors: Cole D C , Ibrahim S A , Shannon H S , Scott F , Eyles J
Published: July 2002

OBJECTIVES

To describe the prevalence of musculoskeletal problems in the Canadian working population and to determine cross sectional associations between such problems and work factors, particularly job strain and physical demand variables.

METHODS

The Canadian 1994 national population health survey (NPHS) sampled 4230 working men and 4043 working women (ages 18–64) who answered an abbreviated version of the job content questionnaire. Workers were classified into four strain categories: high, passive, active, and low. Outcomes were restricted activity due to musculoskeletal disorders and the diagnosis of a back problem (both yes or no). Survey weights were incorporated to allow for different probabilities of selection. Logistic regression analyses were carried out separately for women and men, controlling for sociodemographic factors.

RESULTS

Prevalence of chronic back problems diagnosed by a health practitioner was 14.5% among men and 12.5% among women. Men had a 6.6% prevalence of restricted activity due to musculoskeletal disorders, whereas the corresponding figure for women was 5.3%. Women, but not men, in high strain jobs were more likely to report both back problems (odds ratio (OR) 1.60, 95% confidence interval (95% CI) 1.14 to 2.28) and restricted activity (OR 1.98, 95% CI 1.16 to 3.48) compared with those in low strain jobs. High physical exertion was an independent predictor of back problems in both sexes. For both men and women, low social support at work and high job insecurity were independent predictors of restricted activity due to musculoskeletal disorders. Conversely, chronic back problems contributed to explanation of high job strain among women (OR 1.76, 95% CI 1.30 to 2.39) and high physical exertion among men (OR 1.39, 95% CI 1.09 to 1.77), whereas restricted activity due to musculoskeletal disorders contributed to explanation of high job insecurity in both sexes.

CONCLUSIONS

Associations of interest between work stressors and musculoskeletal problems in this cross sectional study provide evidence for physical and psychosocial factors both affecting disability and being affected by disability in a working population.