bluuebunny/crossref_metadata_2025 huggingface dataset:
THE ARSENIDES OF TUNGSTEN AND MOLYBDENUM: WAs2, W2As3, MoAs2, Mo2As3, AND Mo5As4
Authors: Taylor J. B. , Calvert L. D. , Hunt M. R.
Published: May 2006

Binary alloys in the systems tungsten–arsenic and molybdenum–arsenic have been annealed at temperatures between 600 and 1 000 °C and, after quenching, examined by X-ray diffraction techniques. The only intermediate phases observed are WAs2, W2As3, MoAs2, Mo2As3, and Mo5As4. No solid solubility was detected in the elements or the compounds. The diarsenides are monoclinic, C2, and have the NbAs2 structure. WAs2, a = 9.085 ± 0.002 Å, b = 3.318 ± 0.002 Å, c = 7.690 ± 0.002 Å, β = 119° 31′ ± 2′, MoAs2, a = 9.07 Å, b = 3.30 Å, c = 7.73 Å, β = 119° 20′. The X2As3 compounds are monoclinic, condensed diffraction symbol C*/*; W2As3, a = 13.346 ± 0.002 Å, b = 3.278 ± 0.002 Å, c = 9.599 ± 0.002 Å, β = 124° 48′ ± 2′; Mo2As3, a = 13.339 ± 0.002 Å, b = 3.240 ± 0.002 Å, c = 9.628 ± 0.002 Å, β = 124° 31′ ± 2′. Mo5As4 is tetragonal, I4/m, with the Ti5Te4 structure, a = 9.595 ± 0.001 Å, c = 3.284 ± 0.002 Å. Data for MoAs2 and Mo5As4 confirm or amplify previous reports. In contrast to other reports, MoAs and W2As were not observed. W4As5 and Mo4As5, which have been mentioned briefly elsewhere, are here identified as W2As3 and Mo2As3.
A STUDY OF TAUTOMERISM IN CYCLIC β-DIKETONES BY PROTON MAGNETIC RESONANCE
Authors: Cyr Natsuko , Reeves Leonard W.
Published: May 2006

The keto–enol equilibrium of cyclohexane-1,3-dione in chloroform is best interpreted from proton resonance measurements as[Formula: see text]K1 and K2 may be separately determined from chemical shift measurements of the enol-OH proton and intensity measurements of peaks assigned to keto and enol forms. K1 and K2 are satisfactorily independent of concentrations except in very dilute solutions where intensity measurements become unreliable. The overall equilibrium constant K = K1 × K22 can be obtained for the same molecule in acetonitrile solutions where the enol monomer form is in very low concentration. 5,5′-Dimethylcyclohexane-1,3-dione in chloroform has less enol form than the unsubstituted molecule. The enthalpy change associated with 'K' for cyclohexane-1,3-dione in chloroform is 2.05 ± 0.5 kcal mole−1.
THE REACTION OF OZONE WITH DIMETHYLLAURYLAMINE
Authors: Shulman Garson p.
Published: May 2006

In the oxidation of dimethyllaurylamine in chloroform solution by ozone, increase in temperature results in decreased yields of amine oxide and amine hydrochloride and increased yields of amide and carboxylic acid. The reaction is first order in amine and first order in ozone and is not affected by light. These data are consistent with a mechanism involving oxidation of an amine–chloroform charge transfer complex stable at low temperatures.
EFFECT OF CHANGING pH UPON THE RATE AND MECHANISM OF DECARBOXYLATION OF SUBSTITUTED ANTHRANILIC ACIDS
Authors: Dunn G. E. , Leggate P. , Scheffler I. E.
Published: May 2006

The ionization constants of 4-methoxyanthranilic acid have been determined spectrophotometrically in water at 60 °C and ionic strength 0.10. The variation in rate of decarboxylation with varying pH at constant ionic strength has been measured at 90 °C with 4-methylanthranilic acid and at 60 °C with 4-methoxyanthranilic acid. With each acid the maximum rate occurs at a pH about 2 units less than the isoelectric pH. To account for these results it is necessary to postulate an equilibrium between at least two intermediates formed by protonation of the 1-position of the aromatic ring. One of these must be formed from the anion and the other(s) by protonation of neutral acid and (or) zwitterion.
DIRECT OBSERVATION OF A3Σu+NITROGEN MOLECULES IN THE N–I2 FLAME
Authors: Walton D. I. , McEwan M. J. , Phillips L. F.
Published: May 2006

not available
ON THE FORMATION OF A PYRAZOLINE FROM ACETONE TOLUENESULFONYL HYDRAZONE
Authors: Lin Y.-C. , Just G.
Published: May 2006

not available
PREPARATION OF ANTIDOTES FOR ANTICHOLINESTERASE POISONING III. ESTERS OF 1-ARYLCYCLOALKANECARBOXYLIC ACIDS
Authors: Parkkari J. H. , Bannard R. A. B. , Coleman I. W.
Published: May 2006

not available
HIGH ENERGY MODIFICATIONS OF THE HYDRATES OF ZINC SULFATE
Authors: Jamieson J. W. S. , Lamontagne R. A. , Pattern Barbara A. , Brown G. R.
Published: May 2006

Much higher heats of solution than have previously been observed for hydrates of zinc sulfate have been measured for various new vacuum dehydration products. It is suggested that the maximum heat of transition to normal crystalline form of 82.8 cal/g, 23.8 kcal per mole of heptahydrate, or 8.3 × 103 cm−1 is a satisfactory measure of the ligand field splitting energy for the hexaaquozinc(II) ion.
A NEW SYNTHESIS OF ALKYL FLUORIDES: THE PYROLYSIS OF 2-ALKYLPSEUDOURONIUM FLUORIDES AND FLUOROBORATES
Authors: Amin J. H. , Newton J. , Pattison F. L. M.
Published: May 2006

The pyrolysis of 2-alkylpseudouronium fluorides and fluoroborates at approximately 185° gave alkyl fluorides in yields of up to 77%. The method is most useful for the preparation of primary alkyl fluorides; attempts to prepare secondary fluorides, such as cyclohexyl fluoride, gave the corresponding alkenes.
VIBRATIONAL SPECTRA OF SOME ALKYLARSONIUM COMPOUNDS
Authors: Cullen W. R. , Deacon G. B. , Green J. H. S.
Published: May 2006

The infrared spectra of some tetramethyl-, tetraethyl-, and triethylmethyl-arsonium salts, and that of tetramethylstibonium triiodomercurate(II) have been recorded in the region 4 000 to 200 cm−1. Vibrational assignments are given for the quarternary 'onium cations, and comparisons are made with the spectra of alkylorganometallic compounds of germanium and tin.
THE INFRARED SPECTRA OF SOME TITANIUM (IV) COMPLEXES WITH PRIMARY DIAMINES
Authors: Horley D. , Torrible E. G.
Published: May 2006

A series of titanium(IV) halide – diamine complexes have been prepared and their infrared spectra measured in the solid state between 4 000 and 300 cm−1. The configuration of the ligand and extent of aminolysis of the titanium–halide bond are discussed in relation to the spectra. Some assignments are proposed in the 600–300 cm−1 region for the ethylenediamine complexes.
FRACTIONATION OF PECTINS FROM SUNFLOWERS, SUGAR BEETS, APPLES, AND CITRUS FRUITS
Authors: Zitko V. , Bishop C. T.
Published: May 2006

Pectins from sunflower heads, sugar beet, apple, and citrus fruits were separated into acid-insoluble pectic acids and acid-soluble polysaccharides. The acid-soluble polysaccharides were shown by moving-boundary electrophoresis to be complex mixtures of four or five polysaccharides. The pectic acids were fractionated by precipitation with sodium acetate from aqueous solution. The fractions were examined for galacturonic acid content, specific rotation, limiting viscosity number, behavior on moving-boundary electrophoresis, and presence of neutral sugars. The results showed that each of the pectic acids contained two acidic components, one a galacturonan free of neutral sugars, the other a galacturonan to which neutral sugars were attached, probably as side chains.
ORGANIC SULFUR COMPOUNDS: PART I. BENZOTHIAZINE HYDROXAMIC ACIDS AND RELATED COMPOUNDS
Authors: Coutts R. T. , Peel H. W. , Smith Elizabeth M.
Published: May 2006

2H-1,4-Benzothiazine hydroxamic acids of type V (see Table I) are readily prepared by reducing suitably substituted (o-nitrophenylthio)acetates (II, R″ = Me or Et) by means of sodium borohydride and palladium–charcoal. The ester precursors can be prepared by the interaction of o-nitrothiophenols and α-bromoesters, but such a method is limited in scope. Diethyl bromomalonate, for example, reacts atypically with o-nitrothiophenol. The ester precursors are better prepared by Fischer–Speier esterification of the corresponding acids (II, R″ = H) which, in turn, are the products of nucleophilic attack by α-mercaptoacids on suitable o-chloro- (or bromo-) nitrobenzenes. This general preparative method failed in two instances. When o-chloronitrobenzene or 4-chloro-3-nitrotoluene was reacted with α-mercaptoisobutyric acid, the only acidic product obtained was α.,α′-dithiodiisobutyric acid.Reduction of methyl 2-(o-nitrophenylthio)benzoate (VI) with sodium borohydride and palladium–charcoal gave an azoxy compound, namely 2,2'-bis((o-methoxycarbonyl)phenylthio)azoxybenzene (VII).
DIFFUSENESS IN ELECTRONIC SPECTRA THE VAPOR SPECTRUM OF ANTHRACENE
Authors: Byrne J. P. , Ross I. G.
Published: May 2006

Approximate calculations of the number of rovibronic transitions per unit wavenumber are given for benzene, naphthalene, anthracene, and tetracene. Primarily because of the density of sequence structure all transitions in tetracene vapor should be irresolvably crowded, and hence apparently diffuse, at practical temperatures. Anthracene, whose spectrum has hitherto been described as wholly diffuse, is predicted to be capable of showing resolvable structure at room temperature. At 60 °C and 40 m path a short region of fine sharp structure has been observed. The origin of the first singlet transition is located at 27 688.3 cm−1 (27 757.6 cm−1 in anthracene-d10).
THE INTERACTION OF THE ACETATES AND CARBAMATES OF SOME HETEROCYCLIC ALCOHOLS WITH ACETYLCHOLINESTERASE
Authors: Shaw K. B.
Published: May 2006

The N,N-dimethylcarbamates of 3-quinuclidinol, 1-methyl-3-piperidinol, and 1-methyl-4-piperidinol have been prepared and found to be weak inhibitors of acetylcholinesterase. The acetates of the above alcohols were also prepared and found to be moderately good substrates for this enzyme.
ARYLATION OF AROMATIC COMPOUNDS WITH BENZENEDIAZONIUM BOROFLUORIDE: NATURE OF THE ARYLATING SPECIES
Authors: Abramovitch R. A. , Saha J. G.
Published: May 2006

The decomposition of benzenediazonium borofluoride in a number of aromatic solvents has been studied. The main product is fluorobenzene but some substituted biphenyls are formed. The isomer ratios and apparent total rate ratios for these phenylations have been determined. The results are discussed and it is suggested that the reactive intermediate in the arylations is the phenyl diradical cation.
THE DEPENDENCE OF CONCENTRATION GRADIENT ON CURRENT DENSITY AT WORKING ELECTRODES
Authors: O'Brien R. N. , Rosenfield C. A. , Kinoshita K. , Yakymyshyn W. F. , Leja J.
Published: May 2006

An interferometric study of working electrodes in a cell holding less than 1 ml of solution enabled the effects of cell depth, orientation, electrolyte concentration, and temperature on the concentration gradient to be evaluated. The concentration gradient (obtained from the perturbations of a parallel fringe pattern) is an error function of current density, but every factor studied produced deviation from this relationship. The electrodeposition of the following ions has been studied: Cu++, Zn++, Ni++, Ag+, in a wide variety of electrolytes.
THE STRUCTURE OF AMINOPYRINE SALTS
Authors: Cook Denys
Published: May 2006

The infrared spectra of aminopyrine salts can be interpreted on the basis of protonation of the 4-dimethylamino group nitrogen atom. In the hydrohalides the normal [Formula: see text] hydrogen bond occurs, but in salts with complex anions an intramolecular [Formula: see text] hydrogen bond is probable, though an intermolecular one between the same partners cannot be ruled out.
NUCLEAR MAGNETIC RESONANCE AND INFRARED STUDIES OF ACYLATED IMIDAZOLIDINONES AND IMIDAZOLIDINETHIONES
Authors: Greenhalgh R. , Weinberger M. A.
Published: May 2006

The infrared and nuclear magnetic resonance spectra of 1-acyl and 1,3-diacyl derivatives of 2-imidazolidinones and 2-imidazolidinethiones were determined, where the acyl groups were acetyl, benzoyl, or trifluoroacetyl. The frequency of the ring carbonyl stretching vibration increases with the degree of acylation and the electron-withdrawing power of the acyl group. The methylene protons of the diacylated derivatives show a single peak, the paramagnetic shift of which is similarly dependent on these parameters when the ring current effects are allowed for. This correlation between the νC=O and [Formula: see text] favors the conclusion that the anisotropy of the acyl carbonyl group does not affect the relative methylene proton shift in these compounds and hence they all have the same preferred configuration. This was deduced to be the planar trans,trans structure with respect to the carbonyls. In the unsymmetrical 1,3-diacyl compounds the methylene protons are also nearly equivalent, the τ-value being the average of those for the symmetrical diacyl derivatives. This, together with the changes in the νC=O (acyl), is explained by mesomeric equalization of the electronic environment of nitrogen atoms 1 and 3. The C=S bond is found to have a strong deshielding influence on all protons.
STRUCTURES OF CHLOROBIUM CHLOROPHYLLS (650)
Authors: Purdie J. W. , Holt A. S.
Published: May 2006

The structures of six Chlorobium chlorophylls (650) have been determined. The pheophorbides are derivatives of 2-desvinyl-2-α-hydroxyethyl pyropheophorbide a. Variation of the substituents at C4(isobutyl, n-propyl, or ethyl) and C5(ethyl or methyl) accounts for the six different compounds.
THE CONDENSATION OF PHOSPHONOTHIOIC AND PHOSPHONIC DICHLORIDES WITH o-DIAMINES
Authors: Dannley Ralph L. , Grava Arturs
Published: May 2006

A series of 2,3-dihydro-1H-1,3,2-benzodiazaphosphole 2-sulfides and 2-oxides have been prepared, most commonly by the condensation of a diamine with a phosphonothioic or phosphonic dichloride in a refluxing inert solvent. The phosphonothioic dichlorides react more slowly than the corresponding phosphonic dichlorides, and phenylenediamines containing electron-donating substituents are more reactive than those containing electron-withdrawing substituents. The diazaphosphole 2-oxides undergo hydrolysis or alcoholysis of only one of the amide groups under mild conditions. The 2-sulfides are much more resistant to hydrolysis than the 2-oxides. The 2-sulfides are converted to the N-methyl derivatives by dimethyl sulfate and alkali. The 2-oxides are hydrolyzed under these conditions. The 2-sulfides are invariably lower melting and more soluble in nonpolar solvents than their 2-oxide analogues.
THE REACTION OF SULFONYLIMIDO INTERMEDIATES WITH AROMATIC COMPOUNDS
Authors: Abramovitch R. A. , Roy J. , Uma V.
Published: May 2006

Thermolysis of methanesulfonyl azide in aromatic solvents gives methanesulfonamide and the isomeric methanesulfonanilides. The orientation of the latter and the relative reactivities of the aromatic substrate towards attack by the methylsulfonylimido intermediate have been studied quantitatively. The high reactivity and also great selectivity of the attacking species are interpreted in terms of a rate-determining addition process to give a sulfonylaziridine derivative followed by a product-determining ring opening and rearrangement to the substituted anilides. Partial rate factors are discussed, as are possible mechanisms for the formation of the methanesulfonamide. The methanesulfonylimido intermediate must be abstracting two hydrogen atoms synchronously from the aromatic substrate.
THE SOLUBILITY OF ALUMINIUM IN NaF–AlF3–Al2O3 MELTS
Authors: Thonstad Jomar
Published: May 2006

The solubility of aluminium in NaF–AlF3 melts saturated with alumina has been investigated by analyzing quenched samples of the melts to determine the contents of metallic sodium and aluminium. The total solubility at 1 000 °C given as wt. % Al decreases with decreasing NaF/AlF3 molar ratio from 0.33 wt. % Al at NaF/AlF3 = 6.70 to 0.10 wt. % Al in cryolite (NaF/AlF3 = 3) and 0.075 wt. % Al at NaF/AlF3 = 1.70. The change in the solubility is primarily due to a change in the sodium content, while the aluminium content remains almost constant over the range investigated. The solubility in cryolite increases with increasing temperature from 0.10 wt. % Al at 1 000 °C to 0.14 wt. % Al at 1 060 °C. In cryolite at 1 000 °C the dissolved metal was found to consist of 0.065 wt. % Al and 0.090 wt. % Na. The fraction of the dissolved metal represented by sodium increases with increasing temperature.
DIRECT DISPLACEMENT OF A PRIMARY TOLYL-p-SULFONYLOXY GROUP BY THE METHOXIDE ION: A MORE DIRECT ROUTE TO 5-O-METHYL-L-ARABINOSE AND 3,5-DI-O-METHYL-L-ARABINOSE
Authors: Williams S. C. , Jones J. K. N.
Published: May 2006

not available
SUBSTITUTIONS EN SERIE NAPHTALENIQUE: II. DERIVES DU DIMETHOXY-2,7 NAPHTALENE
Authors: Richer Jean-Claude , Pépin Yvon
Published: May 2006

not available
REACTION OF ARALKYL KETONE PHENYLHYDRAZONES WITH CARBON MONOXIDE; THERMAL INDOLIZATION OF ARALKYL KETONE PHENYLHYDRAZONES
Authors: Rosenthal Alex , Yalpani M.
Published: May 2006

not available
THERMAL REARRANGEMENT OF BENZYLDIMETHYLAMINE OXIDE
Authors: Shulman Garson P. , Ellgen Paul , Connor Margaret
Published: May 2006

not available
AN APPROXIMATE DETERMINATION OF THE SECOND-STAGE PROTONATION CONSTANT FOR 2,2′-BIPYRIDYL, 1,10-PHENANTHROLINE, AND DERIVATIVES
Authors: McBryde W. A. E.
Published: May 2006

not available
THE HEAT OF SUBLIMATION AND HEAT OF VAPORIZATION OF TRIMETHYLTHALLIUM
Authors: Price S. J. , Jacko M. G.
Published: May 2006

not available
REACTIVITY OF CH AND NH BONDS IN ETHYLENIMINE
Authors: Gray Peter , Jones A.
Published: May 2006

not available
DEUTERIUM ISOTOPE EFFECT IN VACUUM-ULTRAVIOLET ABSORPTION COEFFICIENTS OF WATER AND METHANE
Authors: Laufer A. H. , McNesby J. R.
Published: May 2006

not available
MEAN LIFETIME OF FREE RADICAL CHAINS IN 60Co γ-IRRADIATED CHLORAL HYDRATE AND BROMAL HYDRATE SOLUTIONS
Authors: McIntosh R. G. , Eager R. L. , Spinks J. W. T.
Published: May 2006

not available
Behavioral, physiological, and molecular differences in response to dietary restriction in three inbred mouse strains
Authors: Gelegen Cigdem , Collier David A. , Campbell Iain C. , Oppelaar Hugo , Kas Martien J. H.
Published: May 2006

Food restriction paradigms are widely used in animal studies to investigate systems involved in energy regulation. We have observed behavioral, physiological, and molecular differences in response to food restriction in three inbred mouse strains, C57BL/6J, A/J, and DBA/2J. These are the progenitors of chromosome substitution and recombinant inbred mouse strains used for mapping complex traits. DBA/2J and A/J mice increased their locomotor activity during food restriction, and both displayed a decrease in body temperature, but the decrease was significantly larger in DBA/2J compared with A/J mice. C57BL/6J mice did not increase their locomotor activity and displayed a large decrease in their body temperature. The large decline in body temperature during food restriction in DBA/2J and C57BL/6J strains was associated with a robust reduction in plasma leptin levels. DBA/2J mice showed a marked decrease in white and brown adipose tissue masses and an upregulation of the antithermogenic hypothalamic neuropeptide Y Y1 receptor. In contrast, A/J mice showed a reduction in body temperature to a lesser extent that may be explained by downregulation of the thermogenic melanocortin 3 receptor and by behavioral thermoregulation as a consequence of their increased locomotor activity. These data indicate that genetic background is an important parameter in controlling an animal's adaptation strategy in response to food restriction. Therefore, mouse genetic mapping populations based on these progenitor lines are highly valuable for investigating mechanisms underlying strain-dependent differences in behavioral physiology that are seen during reduced food availability.
Acute Cardiovascular and Sympathetic Effects of Nicotine Replacement Therapy
Authors: Najem Boutaïna , Houssière Anne , Pathak Atul , Janssen Christophe , Lemogoum Daniel , Xhaët Olivier , Cuylits Nicolas , van de Borne Philippe
Published: May 2006

Sympathetic overactivity is implicated in the increased cardiovascular risk of cigarette smokers. Excitatory nicotinic receptors are present on peripheral chemoreceptor cells. Chemoreceptors located in the carotid and aortic bodies increase ventilation (Ve), blood pressure (BP), heart rate (HR), and sympathetic nerve activity to muscle circulation (MSNA) in response to hypoxia. We tested the hypothesis that nicotine replacement therapy (NRT) increases MSNA and chemoreceptor sensitivity to hypoxia. Sixteen young healthy smokers were included in the study (8 women). After a randomized and blinded sublingual administration of a 4-mg tablet of nicotine or placebo, we measured minute Ve, HR, mean BP, and MSNA during normoxia and 5 minutes of isocapnic hypoxia. Maximal voluntary end-expiratory apneas were performed at baseline and at the end of the fifth minute of hypoxia. Nicotine increased HR by 7±3 bpm, mean BP by 5±2 mm Hg, and MSNA by 4±1 bursts/min, whereas subjects breathed room air (all
P
<0.05). During hypoxia, nicotine also raised HR by 8±2 bpm, mean BP by 2±1 mm Hg, and MSNA by 7±2 bursts/min (all
P
<0.05). Nicotine increased MSNA during the apneas performed in normoxia and hypoxia (
P
<0.05). Nicotine also raised the product of systolic BP and HR, a marker of cardiac oxygen consumption, during normoxia, hypoxia, and the apneas (
P
<0.05). Ve, apnea duration, and O
2
saturation during hypoxia and the apneas remained unaffected. In conclusion, sympathoexcitatory effects of NRT are not because of an increased chemoreflex sensitivity to hypoxia. NRT increases myocardial oxygen consumption in periods of reduced oxygen availability.
Adiponectin Replenishment Ameliorates Obesity-Related Hypertension
Authors: Ohashi Koji , Kihara Shinji , Ouchi Noriyuki , Kumada Masahiro , Fujita Koichi , Hiuge Aki , Hibuse Toshiyuki , Ryo Miwa , Nishizawa Hitoshi , Maeda Norikazu , Maeda Kazuhisa , Shibata Rei , Walsh Kenneth , Funahashi Tohru , Shimomura Iichiro
Published: May 2006

Patients with obesity are susceptible to hypertension. We have reported that the plasma adiponectin levels are decreased in obesity and that adiponectin has many defensive properties against obesity-related diseases, such as type 2 diabetes and coronary artery disease. The aim of this study was to determine the relationship between adiponectin and hypertension in mice. We measured blood pressure and heart rate directly by a catheter in the carotid artery and indirectly by automatic sphygmomanometer at the tail artery. Obese KKAy mice had significantly lower plasma adiponectin levels and higher systolic blood pressure than control C57BL/6J mice at 21 weeks of age. Adenovirus-delivered adiponectin significantly decreased blood pressure in KKAy mice. The direct role of adiponectin on blood pressure regulation under insulin resistance–free state was investigated in adiponectin-knockout (KO) mice. Adiponectin KO mice developed hypertension when maintained on a high-salt diet (8% NaCl) without insulin resistance. The hypertension of salt-fed adiponectin KO mice was associated with reduced mRNA levels of endothelial NO synthase (eNOS) and prostaglandin I
2
synthase in aorta and low metabolite levels of endothelial NO synthase and prostaglandin I
2
synthase in plasma. Adiponectin therapy lowered the elevated blood pressure and corrected the above mRNA levels to those of the wild type. Our results suggest that hypoadiponectinemia contributes to the development of obesity-related hypertension, at least in part, directly, in addition to its effect via insulin resistance, and that adiponectin therapy can be potentially useful for hypertension in patients with the metabolic syndrome.
Hypoxia-Induced Endothelial NO Synthase Gene Transcriptional Activation Is Mediated Through the Tax-Responsive Element in Endothelial Cells
Authors: Min Jiho , Jin Yoon-Mi , Moon Je-Sung , Sung Min-Sun , Ahn Jo Sangmee , Jo Inho
Published: May 2006

Although hypoxia is known to induce upregulation of endothelial NO synthase (eNOS) gene expression, the underlying mechanism is largely unclear. In this study, we show that hypoxia increases eNOS gene expression through the binding of phosphorylated cAMP-responsive element binding (CREB) protein (pCREB) to the eNOS gene promoter. Hypoxia (1% O
2
) increased both eNOS expression and NO production, peaking at 24 hours, in bovine aortic endothelial cells, and these increases were accompanied by increases in pCREB. Treatment with the protein kinase A inhibitor H-89 or transfection with dominant-negative inhibitor of CREB reversed the hypoxia-induced increases in eNOS expression and NO production, with concomitant inhibition of the phosphorylation of CREB induced by hypoxia, suggesting an involvement of protein kinase A/pCREB-mediated pathway. To map the regulatory elements of the eNOS gene responsible for pCREB binding under hypoxia, we constructed an eNOS gene promoter (−1600 to +22 nucleotides) fused with a luciferase reporter gene [pGL2-eNOS(−1600)]. Hypoxia (for 24-hour incubation) increased the promoter activity by 2.36±0.18-fold in the bovine aortic endothelial cells transfected with pGL2-eNOS(−1600). However, progressive 5′-deletion from −1600 to −873 completely attenuated the hypoxia-induced increase in promoter activity. Electrophoretic mobility shift, anti-pCREB antibody supershift, and site-specific mutation analyses showed that pCREB is bound to the Tax-responsive element (TRE) site, a cAMP-responsive element–like site, located at −924 to −921 of the eNOS promoter. Our data demonstrate that the interaction between pCREB and the Tax-responsive element site within the eNOS promoter may represent a novel mechanism for the mediation of hypoxia-stimulated eNOS gene expression.
Thrombopoietin Protects Against In Vitro and In Vivo Cardiotoxicity Induced by Doxorubicin
Authors: Li Karen , Sung Rita Yn Tz , Huang Wei Zhe , Yang Mo , Pong Nga Hin , Lee Shuk Man , Chan Wood Yee , Zhao Hailu , To Man Yin , Fok Tai Fai , Li Chi Kong , Wong Yuek Oi , Ng Pak Cheung
Published: May 2006

Background—

Doxorubicin (DOX) is an important antineoplastic agent. However, the associated cardiotoxicity, possibly mediated by the production of reactive oxygen species, has remained a significant and dose-limiting clinical problem. Our hypothesis is that the hematopoietic/megakaryocytopoietic growth factor thrombopoietin (TPO) protects against DOX-induced cardiotoxicity and might involve antiapoptotic mechanism exerted on cardiomyocytes.

Methods and Results—

In vitro investigations on H9C2 cell line and spontaneously beating cells of primary, neonatal rat ventricle, as well as an in vivo study in a mouse model of DOX-induced acute cardiomyopathy, were performed. Our results showed that pretreatment with TPO significantly increased viability of DOX-injured H9C2 cells and beating rates of neonatal myocytes, with effects similar to those of dexrazoxane, a clinically approved cardiac protective agent. TPO ameliorated DOX-induced apoptosis of H9C2 cells as demonstrated by assays of annexin V, active caspase-3, and mitochondrial membrane potential. In the mouse model, administration of TPO (12.5 μg/kg IP for 3 alternate days) significantly reduced DOX-induced (20 mg/kg) cardiotoxicity, including low blood cell count, cardiomyocyte lesions (apoptosis, vacuolization, and myofibrillar loss), and animal mortality. Using Doppler echocardiography, we observed increased heart rate, fractional shortening, and cardiac output in animals pretreated with TPO compared with those receiving DOX alone.

Conclusions—

These data have provided the first evidence that TPO is a protective agent against DOX-induced cardiac injury. We propose to further explore an integrated program, incorporating TPO with other protocols, for treatment of DOX-induced cardiotoxicity and other forms of cardiomyopathy.
Histological Assessment of 526 Symptomatic Carotid Plaques in Relation to the Nature and Timing of Ischemic Symptoms
Authors: Redgrave J.N.E. , Lovett J.K. , Gallagher P.J. , Rothwell P.M.
Published: May 2006

Background—

Atherosclerotic plaque at the carotid bifurcation is often associated with transient ischemic attack (TIA) and ischemic stroke, but the mechanisms are not completely understood. Previous histological studies have been too small or insufficiently detailed to reliably determine the temporal course of features of plaque instability or to stratify analyses by the nature of presenting symptoms.

Methods and Results—

We performed the largest-ever histological study of symptomatic carotid plaques from consecutive patients (n=526) undergoing endarterectomy and related detailed reproducible histological assessments to the nature and timing of presenting symptoms. There was a high prevalence of many features of coronary-type plaque instability. Dense plaque inflammation (especially infiltration with macrophages) was the feature most strongly associated with both cap rupture (odds ratio 3.39, 95% confidence interval 2.31 to 4.98,
P
<0.001) and time since stroke (
P
=0.001). Strong negative associations with time since stroke were also seen for cap rupture (
P
=0.02), overall plaque inflammation (
P
=0.003), and “unstable plaque” (
P
=0.001). Although plaques removed ≤60 days after the most recent event were more unstable after a stroke than after a TIA, the instability persisted after a TIA, and plaques removed >180 days after most recent event were less unstable after a stroke than after a TIA (plaque inflammation: ≤60 days, odds ratio 2.33 [95% confidence interval 0.76 to 7.19]; >180 days, 0.36 [0.16 to 0.84];
P
=0.008; unstable plaque: odds ratio 3.27 [95% confidence interval 0.93 to 11.50] versus 0.74 [0.33 to 1.69],
P
=0.05).

Conclusions—

Pathology of recently symptomatic carotid plaques is similar to that of culprit coronary plaques, with strong correlations between macrophage infiltration and plaque instability. The tendency for plaque inflammation and overall instability to persist with time after a TIA but to decrease with time after a stroke suggests that the nature of the underlying pathology may differ.
Personal responsibility for private sector housing renewal: Issues in health improvement
Authors: Stewart Jill , Clayton Julie , Ruston Annmarie
Published: May 2006

Objective To investigate current policy in respect of resourcing private sector housing renewal to promote healthy housing and communities.

Design A qualitative study using focus group research investigating what low-income home owners would find helpful in carrying out maintenance and repair to their homes.

Setting The focus groups were held in the area office of a South London (private sector housing) Renewal Area.

Method Exploratory focus groups were held in 2003 to 2004, to represent low-income ethnically diverse home-owners within the Renewal Area.

Results Respondents were open to looking at new ways of maintaining and repairing their homes, although tended to focus around their own needs rather than the works a local authority may strategically wish to see carried out in private housing sector to meet legal housing standards and promote healthy housing.

Conclusion Local authorities need to be able to find new, evidence-based ways of supporting home-owners to carry out maintenance and repairs to their homes as part of a wider public health agenda.
Justice beyond Blame
Authors: Dimitrijević Nenad
Published: May 2006

Truth commissions have existed as mechanisms of transitional justice in some of the societies confronted with legacies of the criminal past. The author focuses on the question of the foundational justification of the idea of a truth commission. While recognizing the complexity and importance of moral and political considerations that are conventionally invoked to justify the existence of this body, the author aims at offering an alternative justificatory account. The main claim is that the specific task capable of providing the ultimate justification of truth commissions consists of rebuilding the lost sense of justice in the community of perpetrators.
The Contributions of Truth to Reconciliation
Authors: Gibson James L.
Published: May 2006

The South African Truth and Reconciliation Commission (TRC) is undoubtedly the most widely discussed truth and reconciliation process in the world, and by many accounts, the TRC is among the most effective any country has yet produced. What is the explanation for its success? This article has two objectives. First, it seeks to identify the characteristics of South Africa’s truth and reconciliation process that contributed to its performance. Second, it then asks whether the truth and reconciliation process is itself endogenous. Thus, the ultimate objective is to assess whether truth and reconciliation processes can have an independent influence on reconciliation and especially on the likelihood of consolidating an attempted democratic transition. The conclusion of this article is that the truth and reconciliation process in South Africa did indeed exert independent influence on the democratization process through its contributions toward creating a more reconciled society.
Strategy Research and Panel Data: Evidence and Implications
Authors: Certo S. Trevis , Semadeni Matthew
Published: May 2006

A number of studies in strategic management rely on panel (longitudinal) data to test theory. The advantages of panel data notwithstanding, such data introduce analytic problems (e.g., autocorrelation, heteroskedasticity, contemporaneous correlation) that make traditional estimators (e.g., ordinary least squares) inappropriate. This study highlights the influence of contemporaneous correlation, a statistical problem that affects the analysis of panel data. Using Monte Carlo simulations, the authors find that contemporaneous correlation is particularly problematic when analyzing data sets typically used in strategic management research. They suggest straightforward techniques to mitigate the harmful effects of contemporaneous correlation.
“Did I Have Blinders on or What?”
Authors: Aveline David
Published: May 2006

Retrospective sense making is a common practice necessitated by new appearances that contradict old ones. This article examines this practice by parents who have recently learned that their sons are gay. Eighty parents are interviewed, and the data are analyzed for recurrent themes. In efforts to make sense of the past, parents recall much atypical gender behavior in their sons and lack of interest in sports. The article suggests that these behaviors become apparent to the parents because of long-lived cultural scripts equating atypical gender behavior with homosexuality. Parents also reflect on why they had earlier misinterpreted their sons’ behaviors as heterosexual and do so through three methods (revelations, confirmations, and justifications). Theoretical implications as they pertain to the heterosexual presumption and cognitive dissonance are discussed.
Guiding Organizational Identity Through Aged Adolescence
Authors: Corley Kevin G. , Harquail Celia V. , Pratt Michael G. , Glynn Mary Ann , Fiol C. Marlene , Hatch Mary Jo
Published: May 2006

In this article, the authors reflect on the past two decades of research on organizational identity, looking to its history and to its future. They do not provide a review of the literature, nor do they promote a particular perspective on the concept. Instead, they advocate pluralism in studying organizational identity while encouraging clarity and transparency in the articulation of definitions and core theoretical suppositions. Believing there is no one best approach to the study of organizational identity, their intent is to establish a reference point that can orient future work on organizational identity. They focus on three questions they feel are critical: What is the nomological net that embeds organizational identity? Is organizational identity “real” (or simply metaphoric)? and How do we define and conceptualize organizational identity? Last, they try to anticipate organizational identity issues on the horizon to suggest future directions for theory and research.
Munchausen, Black Swans, and the RBV
Authors: Gibbert Michael
Published: May 2006

The critique by Levitas and Ndofor (this issue) challenges the author’s earlier argument (Gibbert, this issue) on three grounds. It starts off by denying the existence of any paradox. Second, they argue that even if there were a paradox, attempts to ensure generalizability would actually hamper, rather than foster the development of the RBV. Finally, they observe that the problems of the RBV extend beyond generalizability and discuss a number of additional problems, in particular—construct validity. It was not within the scope of the author’s original essay to assess the importance of other criteria that can be used to assess the quality of a theory. This response provides an opportunity to address this importance. The author first attempts to clarify the distinction between the logic of a situation and its implied methodology. Confusion of the two motivated, the author believes, Levitas and Ndofor’s critique. The author then uses this distinction to address each of the three criticisms in turn.
Reflections on the Need for “Between Times” and “Between Places”
Authors: Antal Ariane Berthoin
Published: May 2006

This article argues that a great deal of intellectual entrepreneurship happens in times and spaces that lie between institutions. Ideas are often born when people move from one context to another. During “between times” and in “between places” people come up with possibilities that might not fit within one institution alone. The realization of new ideas then requires combining energies and resources from different institutions, and it often involves pushing conventions aside, creating new space between existing institutions. The article explores the example of a business-and-research venture, CHOICE mobilitatsproviding GmbH, to illustrate the importance of multiple types of “between” and their significance for organizational learning.
Choice and Quality in Action Research Practice
Authors: Reason Peter
Published: May 2006

This article explores the nature of quality in action research practice. The origins and purposes of action research and its relation to social science methodology are reviewed. Action research is described in terms of four characteristic dimensions—worthwhile practical purposes, democracy and participation, many ways of knowing, and emergent developmental form—that present a broad range of criteria beyond those of the empirical research paradigm against which quality research might be judged. Recent debates concerning validity and quality in qualitative research are explored. It is argued that action research is characteristically full of choices, and the argument is made that quality in inquiry comes from awareness of and transparency about the choices available at each stage of the inquiry.
A comparison of univariate and multivariate gene selection techniques for classification of cancer datasets
Authors: Lai Carmen , Reinders Marcel JT , van't Veer Laura J , Wessels Lodewyk FA
Published: May 2006

Background

Gene selection is an important step when building predictors of disease state based on gene expression data. Gene selection generally improves performance and identifies a relevant subset of genes. Many univariate and multivariate gene selection approaches have been proposed. Frequently the claim is made that genes are co-regulated (due to pathway dependencies) and that multivariate approaches are therefore per definition more desirable than univariate selection approaches. Based on the published performances of all these approaches a fair comparison of the available results can not be made. This mainly stems from two factors. First, the results are often biased, since the validation set is in one way or another involved in training the predictor, resulting in optimistically biased performance estimates. Second, the published results are often based on a small number of relatively simple datasets. Consequently no generally applicable conclusions can be drawn.

Results

In this study we adopted an unbiased protocol to perform a fair comparison of frequently used multivariate and univariate gene selection techniques, in combination with a ränge of classifiers. Our conclusions are based on seven gene expression datasets, across several cancer types.

Conclusion

Our experiments illustrate that, contrary to several previous studies, in five of the seven datasets univariate selection approaches yield consistently better results than multivariate approaches. The simplest multivariate selection approach, the Top Scoring method, achieves the best results on the remaining two datasets. We conclude that the correlation structures, if present, are difficult to extract due to the small number of samples, and that consequently, overly-complex gene selection algorithms that attempt to extract these structures are prone to overtraining.
Transcriptome coexpression map of human embryonic stem cells
Authors: Li Huai , Liu Ying , Shin Soojung , Sun Yu , Loring Jeanne F , Mattson Mark P , Rao Mahendra S , Zhan Ming
Published: May 2006

Background

Human embryonic stem (ES) cells hold great promise for medicine and science. The transcriptome of human ES cells has been studied in detail in recent years. However, no systematic analysis has yet addressed whether gene expression in human ES cells may be regulated in chromosomal domains, and no chromosomal domains of coexpression have been identified.

Results

We report the first transcriptome coexpression map of the human ES cell and the earliest stage of ES differentiation, the embryoid body (EB), for the analysis of how transcriptional regulation interacts with genomic structure during ES self-renewal and differentiation. We determined the gene expression profiles from multiple ES and EB samples and identified chromosomal domains showing coexpression of adjacent genes on the genome. The coexpression domains were not random, with significant enrichment in chromosomes 8, 11, 16, 17, 19, and Y in the ES state, and 6, 11, 17, 19 and 20 in the EB state. The domains were significantly associated with Giemsa-negative bands in EB, yet showed little correlation with known cytogenetic structures in ES cells. Different patterns of coexpression were revealed by comparative transcriptome mapping between ES and EB.

Conclusion

The findings and methods reported in this investigation advance our understanding of how genome organization affects gene expression in human ES cells and help to identify new mechanisms and pathways controlling ES self-renewal or differentiation.
"Sleepiness" is serious in adolescence: Two surveys of 3235 Canadian students
Authors: Gibson Edward S , Powles AC Peter , Thabane Lehana , O'Brien Susan , Molnar Danielle Sirriani , Trajanovic Nik , Ogilvie Robert , Shapiro Colin , Yan Mi , Chilcott-Tanser Lisa
Published: May 2006

Background

Evidence is growing that sleep problems in adolescents are significant impediments to learning and negatively affect behaviour, attainment of social competence and quality of life. The objectives of the study were to determine the level of sleepiness among students in high school, to identify factors to explain it, and to determine the association between sleepiness and performance in both academic and extracurricular activities

Methods

A cross-sectional survey of 2201 high school students in the Hamilton Wentworth District School Board and the Near North District School Board in Ontario was conducted in 1998/9. A similar survey was done three years later involving 1034 students in the Grand Erie District School Board in the same Province. The Epworth Sleepiness Scale (ESS) was used to measure sleepiness and we also assessed the reliability of this tool for this population. Descriptive analysis of the cohort and information on various measures of performance and demographic data were included. Regression analysis, using the generalised estimating equation (GEE), was utilized to investigate factors associated with risk of sleepiness (ESS>10).

Results

Seventy per cent of the students had less than 8.5 hours weeknight sleep. Bedtime habits such as a consistent bedtime routine, staying up late or drinking caffeinated beverages before bed were statistically significantly associated with ESS, as were weeknight sleep quantity and gender. As ESS increased there was an increase in the proportion of students who felt their grades had dropped because of sleepiness, were late for school, were often extremely sleepy at school, and were involved in fewer extracurricular activities. These performance measures were statistically significantly associated with ESS. Twenty-three percent of the students felt their grades had dropped because of sleepiness. Most students (58–68%) reported that they were "really sleepy" between 8 and 10 A.M.

Conclusion

Sleep deprivation and excessive daytime sleepiness were common in two samples of Ontario high school students and were associated with a decrease in academic achievement and extracurricular activity. There is a need to increase awareness of this problem in the education and health communities and to translate knowledge already available to strategies to address it.
Infant feeding and the media: the relationship between Parents' Magazine content and breastfeeding, 1972–2000
Authors: Foss Katherine A , Southwell Brian G
Published: May 2006

Mass media content likely influences the decision of women to breastfeed their newborn children. Relatively few studies have empirically assessed such a hypothesis to date, however. Most work has tended to focus either on specific interventions or on broad general commentary about the role of media. In this study, we examined infant feeding advertisements in 87 issues ofParents' Magazine, a popular parenting magazine, from the years 1971 through 1999. We then used content analysis results to predict subsequent changes in levels of breastfeeding among U.S. women. When the frequency of hand feeding advertisements increased, the percentage change in breastfeeding rates reported the next year generally tended to decrease. These results underscore the need to acknowledge the potential role of popular media content in understanding breastfeeding patterns and public health trends.
The epidermal growth factor receptor (EGFR) in head and neck cancer: its role and treatment implications
Authors: Zimmermann Michel , Zouhair Abderrahim , Azria David , Ozsahin Mahmut
Published: May 2006

Epidermal growth factor receptor (EGFR) is a member of the ErbB family of receptors. Its stimulation by endogenous ligands, EGF or transforming growth factor-alpha (TGF-α) results in activation of intracellular tyrosine kinase, therefore, cell cycle progression. High levels of EGFR expression are correlated with poor prognosis and resistance to radiation therapy in a variety of cancers, mostly in squamous-cell carcinoma of the head and neck (SCCHN). Blocking the EGFR by a monoclonal antibody results in inhibition of the stimulation of the receptor, therefore, in inhibition of cell proliferation, enhanced apoptosis, and reduced angiogenesis, invasiveness and metastases. The EGFR is a prime target for new anticancer therapy in SCCHN, and other agents in development include small molecular tyrosine kinase inhibitors and antisense therapies.