bluuebunny/crossref_metadata_2025 huggingface dataset:
2',3'-Dideoxy- and 3'-Azido-2',3'-dideoxynucleosides of 5-Phenyl-2(1H)-pyrimidinone. Preparation of 2',3'-Dideoxypentofuranoses
Authors: Krečmerová Marcela , Hřebabecký Hubert , Masojídková Milena , Holý Antonín
Published: July 2002

The synthesis of methyl 3-azido-5-benzoyl-2,3-dideoxy-β-D-ribofuranoside (10) from methyl 2-deoxy-D-ribofuranoside (1) and its use for the preparation of 3'-azido-2',3'-dideoxy-β-D-ribofuranosides is described. Reaction of methylglucoside 1 with benzoyl chloride in pyridine afforded 5-O-benzoyl derivative 2, which on oxidation with complex of chromium trioxide, pyridine and acetic anhydride afforded 3-keto derivative 3. This was reduced with sodium borohydride in ethanol to give a mixture of methyl 2-deoxyglycosides of α-D-ribo- (4) and β-D-xylo- (5) configuration. Their mesyl derivatives 6 and 7 were chromatographically separated. Compound 7 reacted with sodium azide in hot dimethylformamide to afford methyl 3-azido-5-O-benzoyl-2,3-dideoxy-β-D-ribofuranoside (10). 5-Phenyl-2(1H)-pyrimidinone was converted into silyl derivative 11 by treatment with hexamethyldisilazane. Reaction of compound 11 with the azido sugar 10, catalyzed by trimethylsilyl trifluoromethanesulfonate, and subsequent methanolysis, furnished a mixture of anomeric 3'-azido-2',3'-dideoxynucleosides 14 and 15. Methyl 5-O-benzoyl-2,3-dideoxy-α-D-ribofuranoside (17) was prepared from methyl-α-glycoside 4 by reaction with thionyl chloride and subsequent reduction of the obtained 3-chloro derivative 16 with tributylstannane. Silyl derivative 11 reacted with 2,3-dideoxy sugar 17 under catalysis with trimethylsilyl triflate to give mainly 1-(5-O-benzoyl-2,3-dideoxy-α-D-glycero-pentofuranosyl)-5-phenyl-2(1H)-pyrimidinone (19) and minor amount of the β-anomer 18. Their methanolysis afforded dideoxynucleosides 20 and 21.
Synthesis of 5-Phenylcytosine Nucleoside Derivatives
Authors: Krečmerová Marcela , Hřebabecký Hubert , Holý Antonín
Published: July 2002

Reaction of silylated 5-phenylcytosine with 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribose, catalyzed with tin tetrachloride, and subsequent methanolysis afforded 5-phenylcytidine (2). This compound reacted with thionyl chloride in acetonitrile to give cyclic sulfite 3 which on heating in dimethylformamide was converted into 2,2'-anhydro-1-(β-D-arabinofuranosyl)-5-phenylcytosine (4). Analogous reaction of compound 2 with thionyl chloride at reflux gave 5'-chloro-5'-deoxy-2',3'-cyclic sulfite 5. Its heating in dimethylformamide afforded 5'-chloro-2,2'-anhydro derivative 6, mild alkaline hydrolysis led to 5'-chloro-5'-deoxy-5-phenylcytidine (7). Alkaline hydrolysis of 5-phenyl-2,2'-anhydrocytidine (4) gave 5-phenylcytosine arabinoside 8, whereas the 2,2'-anhydro derivative 6 afforded 1-(5-chloro-5-deoxy-β-D-arabinofuranosyl)-5-phenylcytosine (11). At higher temperature, the final reaction product was 2,5'-anhydro-5-phenylcytidine (12). 5'-Chloro-5'-deoxynucleosides 7 and 11 reacted with tri-n-butyl- stannane to give 5'-deoxyribofuranosyl and 5'-deoxyarabinofuranosyl derivatives 15 and 16. 5-Phenylcytidine (2) was converted into the N4-acetate 17 with acetic anhydride. Further reaction with acetic anhydride and hydrogen bromide in acetic acid afforded a mixture of peracetylated 2'-bromo and 3'-bromo derivatives 18 and 19. Reaction with Zn/Cu couple gave 5'-O-acetyl-5-phenyl-2',3'-didehydro derivative 20 and 2',3',5'-tri-O-acetyl-5-phenylcytidine (21). Compound 20 was deblocked to 1-(2,3-dideoxy-β-D-glycero-pent-2-enofuranosyl)-5-phenylcytosine (22). Catalytic hydrogenation of compound 20 over palladium and subsequent deblocking of the protected 2',3'-dideoxy derivative 23 gave 1-(2,3-dideoxy-β-D-glycero-pentofuranosyl)-5-phenylcytosine (24).
Sterically Crowded Heterocycles. V. Incorporation of Melamine and Adenine Moieties into Imidazo[1,2]heteroaromatic Molecules
Authors: Kubík Richard , Kuthan Josef
Published: July 2002

Melamine and adenine react with 2,4,6-triphenylpyrylium perchlorate to corresponding quaternary pyridinium salts 1 and 2, respectively. Ferricyanide oxidation of salt 1 in alkaline medium gave (Z)-3-(2,4-diamino-7-phenylimidazo[1,2-a][1,3,5]triazin-6-yl]-1,3-diphenylprop-2-en-1-one (3). Analogous oxidation of perchlorate 2 afforded (Z)-3-(8-phenylimidazo[1,2-f]-4H-purin-7-yl)-1,3-diphenylprop-2-en-1-one (5).
One-Pot Deuteration and Reduction of Ketones in the Synthesis of [16,16,17-2H3]-Epitestosterone
Authors: Chodounská Hana , Kasal Alexander , Šaman David , Ubik Karel
Published: July 2002

5α-Androstan-17-one and 6β-methoxy-3α,5-cyclo-5α-androstan-17-one were reduced by sodium in deuterium oxide to [16,16,17-2H3]-17β-alcohols. The 17β-tosyloxy group of [16,16,17-2H3]-6β-methoxy-3α,5-cyclo-5α-androstan-17β-ol tosylate was found to be stable under the conditions of the i-steroid rearrangement. The SN2 reaction of the 17β-tosyloxy group with potassium nitrite yielded the corresponding 17α-hydroxy derivative without any loss of deuterium.
Alkoxycarbonylation of Alcohols and Phenols by Nitrosoformates
Authors: Mindl Jaromír , Halama Aleš , Černošek Zdeněk
Published: July 2002

Unstable neutral radicals [ROCONHOU.] 2 and nitrosoformates 3 are formed by oxidation of N-hydroxycarbamates with lead dioxide. In the presence of alcohols or phenols and water they solvolyzed to mixtures of symmetrical 4 and asymmetrical 5 carbonates. The content of asymmetrical carbonates 5 increases with increasing reactivity of the nitrosoformates 3 formed, temperature, the content of water in the reaction mixture, and with decreasing reactivity of alcohol. The reactivities of individual alcohols have been evaluated with the help of competitive alcoholysis. The new method of alcohol or phenol alkoxylation has been verified experimentally by preparing six asymmetrical carbonates which were obtained in 34 to 47% yields.
Peptide Inhibitors of Aspartic Proteinases with Hydroxyethylene Isostere Replacement of Peptide Bond. II. Preparation of Pseudotetrapeptides Derived from Diastereoisomeric 5-Amino-2-benzyl-4-hydroxy-6-phenylhexanoic Acids
Authors: Litera Jaroslav , Weber Jan , Křížová Ivana , Pichová Iva , Konvalinka Jan , Fusek Martin , Souček Milan
Published: July 2002

Twelve pseudotetrapeptides, Boc-NHCH(CH2Ph)CH(OH)CH2CH(CH2Ph) CO-Xaa-Phe-NH2 9-11, were prepared by [(benzotriazol-1-yl)oxy]tris(dimethylamino)phosphonium hexafluorophosphate-mediated couplings of diastereoisomeric O-silylated (2R or 2S,4R or 4S,5S)-2-benzyl-5-(tert-butoxycarbonyl)amino-4-hydroxy-6-phenylhexanoic acids 1 with dipeptides H-Xaa-Phe-NH2 (Xaa = Gln, Glu(OBzl) or Ile) 3-5, followed by O-deprotection. Pseudotetrapeptides 9-11 were tested for inhibition of aspartic proteinases secreted by Candida albicans and C. tropicalis. The level of inhibition of both yeast proteinases was very low, contrasting with the nanomolar IC50 values obtained for inhibition of HIV-1 proteinase.
Polyhedral Azaplatinaborane Chemistry. Reaction of Members of the hypho-Type Family R'H2NB8H11NHR with [PtCl2(PMe2Ph)2] and [PtCl2(PPh3)2]. Formation of Members of the Family of Open Seven-Boron Species [3,3-(PMe2Ph)2-3-PtB7H10-μ-5,6-(NHR)]
Authors: Dörfler Udo , Salter Paul A. , Fontaine Xavier L. R. , Greenwood Norman N. , Kennedy John D. , Thornton-Pett Mark
Published: July 2002

[PtCl2(PMe2Ph)2] and [(R'NH2)NB8H11NHR] (where both R' and R = Et or i-Pr and where R' = i-Pr, R = t-Bu) with NaH and air-exposure gives the series [3,3-(PMe2Ph)2-3-PtB7H10-μ-5,6-(NHR)] (33-44%) of which the structures are closely related to those of the open eight-boron hypho-type starting compounds [(R'NH2)B8H11NHR] by interchange of {BH(NH2R')} and {Pt(PMe2Ph)} vertices, with structural similarities to the rare arachno nine-vertex "normal" B9H15 geometry. Related compounds from related reactions are [(PPh3)2PtB7H10NHEt] and [(PMe2Ph)2PtB7H10NMe2].
Effects of the Nucleophile Structure on the Mechanisms of Reaction of 1-Chloro-2,4-dinitrobenzene with Aromatic Amines in Aprotic Solvents
Authors: Nudelman Norma Sbarbati , Alvaro Cecilia E. Silvana , Savini Monica , Nicotra Viviana , Yankelevich Jeannette
Published: July 2002

The kinetics of reactions of 1-chloro-2,4-dinitrobenzene with aniline and several substituted aromatic amines, B, in toluene shows a quadratic dependence of the second-order rate constant, kA, on [B], which is preserved even in the presence of increasing amounts of dimethylaniline, while the reaction with N-methylaniline shows a linear dependence of kA vs [B]. All these results are interpreted by the "dimer nucleophile" mechanism, and confirmed by the effects of a non-nucleophilic hydrogen bond acceptor tertiary amine which show the relevance of the structure of the nucleophile and the role of mixed aggregates in defining the mechanisms of aromatic nucleophilic substitutions with amines in aprotic solvents.
Effect of Medium on Acid-Catalyzed Decomposition of N-(Phenylazo)-Substituted Nitrogen Heterocycles
Authors: Ludwig Miroslav , Bednářová Iva , Pařík Patrik
Published: July 2002

Four N-(phenylazo)-substituted saturated nitrogen heterocyclics were synthesized and their structure was confirmed by 1H and 13C NMR spectroscopy. The kinetics of their acid-catalyzed decomposition were studied at various concentrations of the catalyst (pivalic acid) in 40, 30, and 20% (v/v) aqueous ethanol at 25 °C. The values obtained for the observed rate constants were processed by the non-linear regression method according to the suggested kinetic models and by the method of principal component analysis (PCA). The interpretation of the results has shown that the acid-catalyzed decomposition of the heterocyclics under the conditions used proceeds by the mechanism of general acid catalysis, the proton being the dominant catalyst particle of the rate-limiting step. The decrease in the observed rate constant at higher concentrations of the catalyst was explained by the formation of a non-reactive complex composed of the undissociated acid and the respective N-(phenylazo)heterocycle. The effect of medium and steric effect of the heterocyclic moiety on the values of catalytic rate constant are discussed.
The Solvation Properties of the Aliphatic Alcohols
Authors: Abraham Michael H. , le Joelle , Acree William E.
Published: July 2002

Solubilities of solute gases and vapours, as log L, where L is the Ostwald solubility coefficient, in the alkan-1-ols from methanol to decan-1-ol have been correlated through the solvation equation of Abraham. It is shown that there is a regular progression of solvent properties from methanol to decan-1-ol, except for the solvent hydrogen-bond basicity that remains the same along the series, and, indeed, is the same as that of water. A slightly different solvation equation is used to correlate the partition of solutes from water to the dry alkanols. For the longer chain alkanols, the coefficients in the solvation equations approach those in equations for partition from water to the wet (water-saturated) alkanols, showing that the solvation properties of the wet and dry alkanols are quite close for the higher alkanol homologues.
The Nature and Transmission of Substituent Electrical Effects in Alicyclic Solvolysis
Authors: Charton Marvin
Published: July 2002

The correlation of rate constants taken from the literature for 2-exo- and 2-endo-norbornyl derivatives substituted in positions 1, 4, 5-exo, 6-exo, 6-endo, and 7-anti with the triparametric LDR equation and relationships derived from it has been carried out. A delocalized (resonance) electrical effect has been found in all but the 4-substituted derivatives. The resonance effect may be somewhat greater when the leaving group is exo than when it is endo. Steric effects occur in the 6-endo-substituted derivatives. The transition state resembles a classical carbocation rather than the nonclassical norbornyl carbocation. The correlation of solvolysis rate constants for 2- and 3-substituted 1- and 4-exo-substituted 2-exo-adamantyl derivatives gave no reliable indication that a delocalized electrical effect existed in these systems. A study of solvolysis rate constants for 4-substituted 1-[2.2.2]bicyclooctanyl, 6-exo-substituted [2.2.2]bicyclooctan-2-exo-yl and 6-exo-substituted [2.2.2]bicyclo- octan-2-endo-yl derivatives showed a delocalized electrical effect only in the latter of these systems. Such an effect was also observed in 4-substituted 2-chloro-2-methylbutane solvolyses. The transmission of electrical effects is by a modified field effect. It is dependent on 1/n where n is the number of bonds intervening between substituent and reaction site.
Separation and Preconcentration of Cr(VI) as Ion Associate Using Solid Phase Extraction
Authors: Otruba Vítězslav , Pivnička Jan , Kanický Viktor
Published: July 2002

A method of separation and preconcentration of Cr(VI) was developed based on sorption on modified silica gel (C18) of an ion associate of Cr(VI) anion with a quaternary base. The study was performed with the following quaternary onium salts: [1-(ethoxycarbonyl)- pentadecyl]trimethylammonium bromide, 1-hexadecylpyridinium chloride, benzyl(dodecyl)- dimethylammonium bromide, butyl(triphenyl)phosphonium bromide and tetraphenylarsonium chloride. Benzyl(dodecyl)dimethylammonium bromide was found the optimum ion-pairing reagent. Sample containing Cr(III) and Cr(VI) in the presence of 0.005 mol/l of benzyl(dodecyl)dimethylammonium bromide was pumped with a peristaltic pump through the column containing the sorbent. The optimum pH range 4-5 was maintained with 0.05 mol/l phosphate buffer. Elution was accomplished using 95 vol.% ethanol and the recovery of Cr(VI) was (96 ± 6)% in the concentration range 0.005-1 mg/l of Cr(VI); even in a tenfold excess of Cr(III) the recovery of Cr(VI) was 99.8% with the relative standard deviation of repeatability about 2.4% Cr in the eluate was determined by emission flame spectrometry (Cr I 425.435 nm) in an air-acetylene or N2O-acetylene flame with the limits of detection 10 or 2 ng/ml, respectively. Hence, with a typical preconcentration factor of 200, the limits of detection in natural aqueous samples were 50 and 10 pg/ml, respectively. Calibrations were linear at least up to 10 mg/l.
Amperometric Determination of Glucose with a Carbon Paste Biosensor
Authors: Schachl Klemens , Turkušić Emir , Komersová Alena , Bartoš Martin , Moderegger Helmut , Švancara Ivan , Alemu Hailemichael , Vytřas Karel , Jimenez-Castro Maria , Kalcher Kurt
Published: July 2002

A simple glucose biosensor has been developed by bulk modification of a carbon paste electrode with glucose oxidase as a biocomponent and manganese dioxide as a mediator. The sensor was employed as amperometric detector in a flow-injection system at 21 °C in 0.2 M phosphate buffer (pH 7.5). At an applied working potential of 0.48 V vs Ag/AgCl and a flow rate of 0.2 ml min-1, the sensor exhibited well reproducible amperometric response to glucose. A linear relation between the peak current and the analyte concentration was found between 20 and 500 mg l-1 glucose with a detection limit (3σ) of 10.5 mg l-1 glucose. The sensor can be operated continuously for 12 h without any loss in the signal height and can be used for the determination of glucose in white wine samples.
Methods, advantages, and limitations of body cooling for exercise performance
Authors: Marino F E
Published: July 2002

Precooling studies confirm that increasing body heat is a limiting factor during exercise. However, it seems that precooling is only beneficial for endurance exercise of up to 30–40 minutes rather than intermittent or short duration exercise.
Candidate gene regions and genetic heterogeneity in gluten sensitivity
Authors: Holopainen P , Mustalahti K , Uimari P , Collin P , Mäki M , Partanen J
Published: July 2002

BACKGROUND

Gluten sensitivity is a common multifactorial disorder, manifested in the small intestine or on the skin as typical coeliac disease or dermatitis herpetiformis, respectively. The only established genetic risk factor is HLA DQ2.

AIMS

We tested genetic linkage of previously reported chromosomal loci 5q and 11q in Finnish families with gluten sensitivity. We also tested if genetic linkage to candidate loci on 5q, 11q, 2q33, and HLA DQ differed with respect to clinical manifestations or sex.

SUBJECTS

We studied 102 Finnish families with affected sibpairs. For heterogeneity analysis, families were divided into subgroups according to sex and the presence of dermatitis herpetiformis, the skin manifestation of gluten sensitivity.

METHODS

Non-parametric linkage between microsatellite markers and disease was tested. Linkage heterogeneity between subgroups was tested using the M test. The transmission/disequilibrium test and association analysis were performed.

RESULTS

Evidence of linkage to 11q (MLS 1.37), but not to 5q, was found in the entire dataset of 102 families. Heterogeneity between subgroups was suggested: families with only the intestinal disease showed linkage mainly to 2q33 whereas families with dermatitis herpetiformis showed linkage to 11q and 5q, but not to 2q33. Linkage in all three non-HLA loci was strongest in families with predominantly male patients. HLA DQ2 conferred much stronger susceptibility to females than males.

CONCLUSIONS

Independent evidence for the suggested genetic linkage between 11q and gluten sensitivity was obtained. The possible linkage heterogeneity suggests genetic differences between intestinal and skin manifestations, and the gender dependent effect of HLA DQ2.
Keratinocyte growth factor and coeliac disease
Authors: Salvati V M , Bajaj-Elliott M , Poulsom R , Mazzarella G , Lundin K E A , Nilsen E M , Troncone R , MacDonald T T
Published: July 2002

BACKGROUND

Coeliac disease is characterised by increased epithelial renewal associated with a mucosal T cell response to gliadin. Keratinocyte growth factor (KGF) is produced by cytokine activated gut stromal cells and may be a link between mucosal T cell activation in untreated coeliac disease and epithelial hyperplasia.

AIMS

To characterise expression of KGF in coeliac disease.

METHODS

KGF transcripts in coeliac disease were measured by quantitative competitive reverse transcription-polymerase chain reaction (RT-PCR) and localised using in situ hybridisation. KGF production by gluten reactive CD4+ T cell clones was examined. In addition, KGF transcripts were measured following ex vivo challenge of coeliac biopsies with a peptic-tryptic digest of gliadin.

RESULTS

KGF transcripts were elevated in coeliac biopsies compared with normal controls but were not different from non-coeliac disease controls. By in situ hybridisation, KGF mRNA containing cells were present in the upper half of the lamina propria, most abundantly just under the epithelium. There was no signal from cells within the epithelium. Gluten reactive T cell clones did not make KGF. In vitro challenge of coeliac biopsies generated a strong interferon γ response but a specific KGF response could not be detected because of an extremely high number of KGF transcripts in all cultured biopsies.

CONCLUSIONS

KGF is overexpressed in coeliac biopsies and in tissues with non-coeliac enteropathy. No evidence was found for KGF production by intraepithelial lymphocytes or lamina propria T cells.
Fetal origins of adult disease: epidemiology and mechanisms
Authors: Byrne C D , Phillips D I
Published: July 2002

The past 10 years have provided unequivocal evidence that there are associations between birth size measures and future development of adult diseases, such as type 2 diabetes and coronary artery disease. Despite initial concern that bias or residual confounding in the analyses had produced these rather bizarre associations, the findings have now been reproduced in different cohorts by independent investigators from many parts of the world. The challenge for the next decade must be to discover the cellular and molecular mechanisms giving rise to these associations. If this aim is accomplished, it might be possible to devise strategies to reduce the impact of these disabling, chronic, and expensive diseases. The purpose of this review is to describe some of the relevant, important, and more recent epidemiological studies, and also to discuss potential mechanisms underpinning the associations.J Clin Pathol(J Clin Pathol 2000;53:822–828)
Deciding for imperilled newborns: medical authority or parental autonomy?
Authors: McHaffie Hazel E , Laing Ian A , Parker Michael , McMillan John
Published: July 2002

The ethical issues around decision making on behalf of infants have been illuminated by two empirical research studies carried out in Scotland. In-depth interviews with 176 medical and nursing staff and with 108 parents of babies for whom there was discussion of treatment withholding/withdrawal, generated a wealth of data on both the decision making process and the management of cases. Both staff and parents believe that parents should be involved in treatment limitation decisions on behalf of their babies. However, whilst many doctors and nurses consider the ultimate responsibility too great for families to carry, the majority of parents wish to be the final arbiters. We offer explanations for the differences in perception found in the two groups. The results of these empirical studies provide both aids to ethical reflection and guidance for clinicians dealing with these vulnerable families. They demonstrate the value of empirical data in the philosophical debate.
Reporting of occupational and environmental research: use and misuse of statistical and epidemiological methods
Authors: Rushton Lesley
Published: July 2002

OBJECTIVES

To report some of the most serious omissions and errors which may occur in papers submitted toOccupational and Environmental Medicine, and to give guidelines on the essential components that should be included in papers reporting results from studies of occupational and environmental health.

METHODS

Since 1994Occupational and Environmental Medicinehas used a panel of medical statisticians to review submitted papers which have a substantial statistical content. Although some studies may have genuine errors in their design, execution, and analysis, many of the problems identified during the reviewing process are due to inadequate and incomplete reporting of essential aspects of a study. This paper outlines some of the most important errors and omissions that may occur. Observational studies are often the preferred choice of design in occupational and environmental medicine. Some of the issues relating to design, execution, and analysis which should be considered when reporting three of the most common observational study designs, cross sectional, case-control, and cohort are described. An illustration of good reporting practice is given for each. Various mathematical modelling techniques are often used in the analysis of these studies, the reporting of which causes a major problem to some authors. Suggestions for the presentation of results from modelling are made.

CONCLUSIONS

There is increasing interest in the development and application of formal “good epidemiology practices”. These not only consider issues of data quality, study design, and study conduct, but through their structured approach to the documentation of the study procedures, provide the potential for more rigorous reporting of the results in the scientific literature.
Low level exposure to cadmium and early kidney damage: the OSCAR study
Authors: Järup Lars , Hellström Lennart , Alfvén Tobias , Carlsson Margareta D , Grubb Anders , Persson Bodil , Pettersson Conny , Spång Gunnar , Schütz Andrejs , Elinder Carl-Gustaf
Published: July 2002

OBJECTIVES

To study the dose-response relation between cadmium dose and renal tubular damage in a population of workers and people environmentally or occupationally exposed to low concentrations of cadmium.

METHODS

Early kidney damage in 1021 people, occupationally or environmentally exposed to cadmium, was assessed from cadmium in urine to estimate dose, and protein HC (α1-microglobulin) in urine to assess tubular proteinuria.

RESULTS

There was an age and sex adjusted correlation between cadmium in urine and urinary protein HC. The prevalence of tubular proteinuria ranged from 5% among unexposed people to 50% in the most exposed group. The corresponding prevalence odds ratio was 6.0 (95% confidence interval (95% CI) 1.6 to 22) for the highest exposure group, adjusted for age and sex. Multiple logistic regression analysis showed an increasing prevalence of tubular proteinuria with urinary cadmium as well as with age. After adjustment to the mean age of the study population (53 years), the results show an increased prevalence of 10% tubular proteinuria (taking into account a background prevalence of 5%) at a urinary cadmium concentration of 1.0 nmol/mmol creatinine.

CONCLUSION

Renal tubular damage due to exposure to cadmium develops at lower levels of cadmium body burden than previously anticipated.
Exposure to tremolite asbestos and respiratory health in Swedish dolomite workers
Authors: Seldén A I , Berg N P , Lundgren E A L , Hillerdal G , Wik N-G , Ohlson C-G , Bodin L S
Published: July 2002

OBJECTIVES

Deposits of carbonate rock like limestone and dolomite may contain tremolite asbestos. This study assessed the exposure to tremolite asbestos and the respiratory health of Swedish dolomite workers.

METHODS

95% of 137 eligible workers at two dolomite producing companies completed a self administered questionnaire that included questions on respiratory symptoms and were examined with spirometry as well as chest radiography. Total exposure to dust was gravimetrically measured and the tremolite asbestos content of the dust was assessed with polarisation and phase contrast microscopy.

RESULTS

Dolomite dust concentrations were moderate (median 2.8 mg/m3) and tremolite asbestos concentrations were generally below the limit of detection (<0.03 fibres/ml). Somewhat higher values, around 0.1 fibres/ml, were obtained in manual stone sorting and bagging. Respiratory symptoms suggestive of chronic bronchitis were more related to smoking than to estimates of individual exposure to dust. The mean vital capacity was 0.2 l lower than expected after adjustment for sex, age, height, and smoking but the decline in lung function was not associated with current or cumulative exposure to dust in a clear cut way. Two definite cases of pleural plaques and one possible case of simple pneumoconiosis were noted, but the plaques could not be attributed exclusively to exposure to tremolite asbestos.

CONCLUSIONS

Dolomite mining and milling may indeed entail low levels of exposure to tremolite asbestos, but this exposure was not a strong determinant of respiratory symptoms, lung function, or pneumoconiosis in exposed Swedish workers. This was true also for dolomite dust. The hazards of exposure to tremolite asbestos may vary across deposits, however, and additional studies at other sites of carbonate rock exploitation are warranted.
Sweet's syndrome and subacute thyroiditis
Authors: Kalmus Yoav , Kovatz Susy , Shilo Lotan , Ganem Gazi , Shenkman Louis
Published: July 2002

A 63 year old woman developed biopsy documented lesions of acute febrile neutrophilic dermatosis (Sweet's syndrome) one week after the onset of subacute thyroiditis. This is only the second reported case of such an association. The role of cytokines in the development of both subacute thyroiditis and Sweet's syndrome may be the link between these two conditions.
Colchicine induced rhabdomyolysis
Authors: Chattopadhyay I , Shetty H G M , Routledge P A , Jeffery J
Published: July 2002

A case of colchicine induced rhabdomyolysis is reported. A 73 year old man with ischaemic heart disease, atrial fibrillation, chronic congestive cardiac failure, and chronic gout presented with diffuse muscle pain. He had been taking an increased dose of colchicine (1.5 mg daily) for an exacerbation of gout for six weeks before the presentation. Investigations confirmed the diagnosis of rhabdomyolysis and discontinuation of colchicine resulted in resolution of clinical and biochemical features of rhabdomyolysis. Although neuromuscular adverse effects of colchicine are well recognised, rhabdomyolysis is rare and this is only the fourth reported case of colchicine induced rhabdomyolysis in the literature.
Philip Morris' new scientific initiative: an analysis
Authors: HIRSCHHORN NORBERT , BIALOUS STELLA AGUINAGA , SHATENSTEIN STAN
Published: July 2002

In the fall of 2000, Philip Morris re-initiated an external research grants programme (“Philip Morris External Research Program”, or PMERP), the first since the dissolution of the Council for Tobacco Research (CTR) and the Center for Indoor Air Research (CIAR). The ostensible purpose of the programme is to help develop cigarette designs “that might reduce the health risk of smoking”. Internal company documents also indicate that Philip Morris urgently seeks to restore its scientific “credibility”, as part of a “new openness” in relation to the external community. The structure of the review panel—a cohort of external peer reviewers, a science advisory board, and an internal, anonymous review and approvals committee—is nearly identical to that of the CIAR. The majority of the named reviewers have had previous affiliation with the tobacco industry either as reviewers or grantees, but only a minority have done research directly on tobacco or smoking. The programmatic substance of the PMERP could be interpreted as soliciting exculpatory evidence with respect to smoking and exposure to smoke. We remain sceptical about the scientific integrity of PMERP.
Characterization of high arctic stream diatom assemblages from Cornwallis Island, Nunavut, Canada
Authors: Antoniades Dermot , Douglas Marianne SV
Published: July 2002

Distinct diatom assemblages often characterize stream habitats, providing the potential to reconstruct past precipitation, snowmelt, and streamflow levels in high arctic watersheds by analyzing fossil assemblages preserved in downstream lake sediments. Diatom assemblages were studied from seven streams and two rivers surrounding Lake Sophia, Cornwallis Island, Nunavut, Canada (75°06' N, 93°36' W). A total of 64 diatom taxa were identified from epilithic and epiphytic assemblages in these lotic habitats. Of these, certain diatom taxa exhibited clear microhabitat preferences. Hannaea arcus (Ehrenberg) Patrick, Achnanthes minutissima (Kützing) Hustedt, Achnanthes petersenii Hustedt, and Meridion circulare (Greville) Agardh were the most common taxa on epilithic substrates, and as a group made up 6195% of the diatom epilithon. Achnanthes taxa (mainly A. petersenii and A. minutissima) were the dominant taxa in moss habitats, representing between 45 and 73% of the diatom epiphyton. The relative abundance of H. arcus in epilithic habitats was negatively correlated with water temperature (r2= 0.71, n = 8). Hannaea arcus was found in greater abundances in cool, fast-flowing streams. This apparent correlation may more closely reflect current speed, which is inversely correlated to temperature in these streams. When these streams discharge into lake basins, the characteristic stream diatoms H. arcus and M. circulare are deposited in lakes. These diatom taxa have the potential to infer past streamflows using paleolimnological techniques.Key words: diatoms, arctic, stream, rheophilous, Lake Sophia, Hannaea arcus.
Architectural and genotypic variation in the clonal shrub Taxus canadensis as determined from random amplified polymorphic DNA and amplified fragment length polymorphism
Authors: Corradini Pierre , Edelin Claude , Bruneau Anne , Bouchard André
Published: July 2002

Canada yew (Taxus canadensis Marsh.) is a clonal species with two types of ramets. The most common type has bilateral symmetry and alternate branching. The radial symmetry and opposite branching of the rarer type are similar to the architecture expressed in a young plant grown from seed. Architectural analysis was conducted on four colonies of increasing age and size. A genetic analysis using random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) was conducted on 122 ramets, 93 sampled from nine colonies from a single population, 24 from eight other populations, and five from other Taxus species. Analysis of the architectural development sequence shows that yew follows the same architectural model as, for example, species of Abies or Picea. This model constitutes a level of organization intermediate between that of the ramet and of the genet. The molecular analyses confirm the greater variability of AFLPs over RAPDs and indicate that architecture is not directly related to genotypic variation. Ramets with radial symmetry have slightly higher genetic variation, on average, than ramets with bilateral symmetry with 95% degree of confidence. The molecular analyses show that the level of resolution of the AFLPs is adequate to characterize 98% of the ramets of a colony. Between pairs of physically connected ramets, some random genotypic differences are observed, supporting the hypothesis of genetic mosaicism in plants, due to somaclonal variations.Key words: architecture, clonal plant, intraclonal variation, molecular markers, somaclonal mutations.
Climatic factors controlling reproduction and growth of Norway spruce in southern Norway
Authors: Selås Vidar , Piovesan Gianluca , Adams Jonathan M , Bernabei Mauro
Published: July 2002

Time series of seed production and tree-ring width of Norway spruce (Picea abies (L.) Karst.) in southern Norway were analysed for their relationship to various climatic factors occurring during "key" stages, which a priori might be expected to show a strong climate response. The following factors combined in a multiple linear regression model were found to predict seed production (based on withheld data points) with considerable accuracy, at high levels of statistical significance: JuneJuly mean temperature and August lowest temperature in the previous year, late spring frost and JuneJuly precipitation of the last 2 years, and JanuaryFebruary lowest temperature in the current year. Tree ring width was negatively correlated with the seed production index of the current year and the lowest July temperature in the previous year and positively correlated with June-July precipitation in the current year. It is suggested that habitat constraints for seedling establishment should also be considered in a more general life-history cost theory to explain masting behaviour in forest trees.
Trophic ecology of bowhead whales (Balaena mysticetus) compared with that of other arctic marine biota as interpreted from carbon-, nitrogen-, and sulfur-isotope signatures
Authors: Hoekstra P F , Dehn L A , George J C , Solomon K R , Muir D CG , O'Hara T M
Published: July 2002

In this study, stable carbon (δ13C), nitrogen (δ15N), and sulfur (δ34S) isotope ratios were measured in muscle tissue from the BeringChukchiBeaufort Sea population of bowhead whales (Balaena mysticetus; n = 84) and various marine biota between 1997 and 2000. In previous investigations, stable carbon and nitrogen isotope ratios in baleen from this population have been used to elucidate age, migratory behaviour, and feeding ecology. However, information on δ13C, δ15N, and δ34S isotope patterns in bowhead whale muscle tissue and variability within the Bering Sea population is limited. Stable sulfur isotope values did not vary with δ13C enrichment for three consecutive seasons (n = 53) and this suggests that habitat selection by bowhead whales was consistent over the sampling period. We found that in contrast to other studies, seasonal differences (spring versus fall) in δ13C values were not associated with seasonal changes in δ15N values, suggesting either that bowhead whales maintain a consistently lower trophic position relative to other marine mammals or that stable carbon and nitrogen isotope fractionation is tissue-dependent and (or) isotope-dependent within this species. Seasonal fluctuation in δ13C values was consistent for all age classes of bowhead whales and suggests that the Bering and Beaufort seas are both important regions for feeding.
LOCAL QUANTUM CONSTRAINTS
Authors: GRUNDLING HENDRIK , LLEDÓ FERNANDO
Published: July 2002

We analyze the situation of a local quantum field theory with constraints, both indexed by the same set of space-time regions. In particular we find "weak" Haag–Kastler axioms which will ensure that the final constrained theory satisfies the usual Haag–Kastler axioms. Gupta–Bleuler electromagnetism is developed in detail as an example of a theory which satisfies the "weak" Haag–Kastler axioms but not the usual ones. This analysis is done by pure C*-algebraic means without employing any indefinite metric representations, and we obtain the same physical algebra and positive energy representation for it than by the usual means. The price for avoiding the indefinite metric, is the use of nonregular representations and complex valued test functions. We also exhibit the precise connection with the usual indefinite metric representation.

We conclude the analysis by comparing the final physical algebra produced by a system of local constrainings with the one obtained from a single global constraining and also consider the issue of reduction by stages. For the usual spectral condition on the generators of the translation group, we also find a "weak" version, and show that the Gupta–Bleuler example satisfies it.
ASYMPTOTIC BEHAVIOR OF SOME HANKEL-TOEPLITZ DETERMINANTS
Authors: BAKER GEORGE A. , BESSIS DANIEL , MOUSSA PIERRE
Published: July 2002

Motivated by the recent increase in interest in Toeplitz determinants of large order, whose elements are moments with respect to measures, by their connection with the theory of quantum gravity we have given exact values of the determinants for several large classes of measures. These classes are related to the continued fraction of Gauss and its q-extension. We have proven that the q-extension, which is related to the theory of quantum groups, is unique. In addition we have extended the work of Szegő from measures of finite support to a wide class of those with infinite support.
ON THE THERMODYNAMIC FORMALISM FOR MULTIFRACTAL FUNCTIONS
Authors: DAUBECHIES INGRID , LAGARIAS JEFFREY C.
Published: July 2002

The thermodynamic formalism for "multifractal" functions φ(x) is a heuristic principle that states that the singularity spectrum f(α) (defined as the Hausdorff dimension of the set Sα of points where φ has Hölder exponent α) and the moment scaling exponent τ(q) (giving the power law behavior of ∫ |φ(x + t) – φ (x)|q dx for small |t|) should be related by the Legendre transform, [Formula: see text]. The range of validity of this heuristic principle is unknown. Here this principle is rigorously verified for a family of "toy examples" that are solutions of refinement equations. These example functions exhibit oscillations on all scales, and correspond to multifractal signed measures rather than multifractal measures; moreover, their singularity spectra f(α) are not concave.
DIAMAGNETIC INEQUALITIES FOR SYSTEMS OF NONRELATIVISTIC PARTICLES WITH A QUANTIZED FIELD
Authors: HIROSHIMA FUMIO
Published: July 2002

By unitary transformations (gauge transformations, the Bogoliubov transformations) and the strong Trotter product formula, diamagnetic inequalities for the Pauli-Fierz model of quantum electrodynamics (QED) and the Nelson model are derived. In the Nelson model, the unitary transformation defines effective potentials. Moreover, the infimum of the spectrum of Hamiltonians for these models are estimated and some generalized Kato’s inequalities are obtained.
ON AUTOMORPHISMS OF GENERALIZED CUNTZ ALGEBRAS
Authors: KATAYAMA YOSHIKAZU , TAKEHANA HIROAKI
Published: July 2002

Let X be a full right Hilbert B-bimodule of finite type and [Formula: see text] be its generalized Cuntz algebra. We give a notion that the C*-algebra B is X-aperiodic. We show that the fixed point algebra ℱX for a gauge action is simple if and only if the C*-algebra B is X-aperiodic. For a invertible operator U on X with some properties, a quasi-free automorphism αU of [Formula: see text] is defined. We give some conditions in order that αU is inner in the case that B is X-aperiodic. We apply them to the automorphism αU on Cuntz–Krieger algebras.
Magnets on Ears Helped Diabetics
Authors: Chen Yu
Published: July 2002

Magnets were attached on auricular acupuncture points of diabetes patients. This treatment lowered the blood glucose levels and improved eye conditions.
HIGH-EFFICIENCY READOUT OF SCINTILLATING FIBERS BY AVALANCHE PHOTODIODES
Authors: YOSHIDA TAKUO , OKUSAWA TORU , SORA TAKEFUMI , YAMASAKI MITSUO
Published: July 2002

We have evaluated the performance of a short-wavelength enchanced type APD as a photosensor for a 3-m long scintillating fiber. By cooling the APD down to -40°C or below, the detection efficiency for a minimum ionizing particle reached nearly 100%.
The MINOS Magnets
Authors: Nelson J. K.
Published: July 2002

The MINOS long baseline neutrino oscillation experiment will consists of two magnetized tracking calorimeters one on the Fermilab site and one in Minnesota. This paper summarizes the design, magnetic performance, and status of the MINOS magnets.
ENERGY AND MOMENTUM OF A CLASS OF ROTATING GRAVITATIONAL WAVES
Authors: SHARIF M.
Published: July 2002

We calculate energy and momentum for a class of cylindrical rotating gravitational waves using Einstein and Papapetrou's prescriptions. It is shown that the results obtained are reduced to the special case of the cylindrical gravitational waves already available in the literature.
SCHRÖDINGER EQUATIONS WITH TIME-DEPENDENT P2 AND X2 TERMS
Authors: NIETO MICHAEL MARTIN , TRUAX D. RODNEY
Published: July 2002

We present some general results for the time-dependent mass Hamiltonian problem with H=-½e-2ν(t)∂xx+h(2)(t)e2ν(t)x2, where ν(t) is a continuous function of t. This Hamiltonian corresponds to a time-dependent mass (TM) Schrödinger equation with the restriction that there are only P2 and X2 terms. We give the specific transformations to a different quadratic Schrödinger (TQ) equation and to a different time-dependent oscillator (TO) equation. For each Schrödinger system, we give the Lie algebra of space–time symmetries and (x,t) representations for number states, coherent states and squeezed states. These general results include earlier works as special cases.
HIGH-RESOLUTION HIGH ENERGY X-RAY DIFFRACTION STUDIES OF CHARGE ORDERING IN CMR MANGANITES AND NICKELATES
Authors: WILKINS STUART B. , HATTON PETER D. , LISS KLAUS-DIETER , OHLER M. , KATSUFUJI T. , CHEONG S.-W.
Published: July 2002

High-resolution, high-energy, X-ray diffraction results are presented for the study of weak charge ordering phenomenon. By utilizing X-rays in the 100 keV region the dramatic increase in the penetration depth allows for both bulk-sensitive and high-resolution measurements to be made. The strontium doped La 2 NiO 4 system is a prototypical system in the understanding of strong electron-phonon coupling, and the resultant effects on material properties. At doping levels of 1/3 and 1/2 commensurate charge modulations are observed indicating real-space charge stripes. We have measured the correlation lengths of these charge stripes using both 100 keV X-rays and 8.3 keV X-rays. In comparing our results we have observed that the charge stripes appear to be well correlated in the near-surface region with correlation lengths ξ≈2400Å. However, our bulk sensitive measurements show that the charge stripes appear in a possible stripe glass phase with a correlation length of only ξ≈300Å. Our measurements on the 3D charge order manganite system Nd 0.5 Sr 0.5 MnO 3 show that the charge ordering appears to be well correlated in the bulk of the sample in contrast to our nickelate results.
ANTHONY LEGGETT: FEENBERG MEDALIST 1999 CONDENSED MATTER AS A TEST-BED FOR FUNDAMENTAL QUANTUM MECHANICS
Authors: CAMPBELL C. E. , CLARK J. W. , KROTSCHECK E. , PITAEVSKII L. P.
Published: July 2002

The Eugene Feenberg Medal is awarded to Anthony J. Leggett in recognition of his seminal contributions to Many-Body Physics, including the explanation of the remarkable properties of superfluid 3 He in the millikelvin regime, important results in Fermi-liquid theory applied to metals, fundamental new insights into macroscopic quantum coherence, elucidation of key aspects of high-temperature superconductivity, and pioneering studies of the implications of Bose-Einstein condensation in atomic systems.
ELECTRON–PHONON INTERACTIONS CAUSE HTSC
Authors: PHILLIPS J. C.
Published: July 2002

What is the microscopic interaction responsible for high temperature superconductivity (HTSC)? Here data on temporal relaxation of T c and the room temperature conductivity in YBa2Cu3O 6+x after abrupt alteration by light pulses or pressure changes are analyzed. The analysis proves, independently of microscopic details, that only electron–phonon interactions can cause HTSC in the cuprates; all other dynamical interactions are excluded by experiment.
SURFACE BONDING STATES OF NANO-CRYSTALLINE DIAMOND BALLS
Authors: PENG J. L. , BULCOCK SHAUN , BELOBROV PETER I. , BURSILL L. A.
Published: July 2002

The rough surface of nano-crystalline diamond spheres induces surface electronic states which appear as a broadened pre-peak over approx. 15 eV at the C K-edge energy threshold for carbon in the parallel electron energy loss spectrum (PEELS). This appears to be at least partially due to 1s-π* transitions, although typically the latter occupy a range of only 4 eV for the sp2 edge of highly-oriented pyrollytic graphite (HOPG). No π* electrons appear in the conduction band inside the diamond particles, where all electrons are sp3 hybridized. PEELS data were also obtained from a chemical vapour deposited diamond film (CVDF) and gem-quality diamond for comparison with the spectra of nano-diamonds.

The density of sp2 and sp3 states on the surface of diamond nano-crystals is calculated for simple structural models of the diamond balls, including some conjecture about surface structures. The results are used to interpret the sp2/sp3 ratios measured from the PEELS spectra recorded as scans across the particles. Surface roughness at the atomic scale was also examined using high-resolution transmission electron microscopy (HRTEM) and electron nano-diffraction patterns were used to confirm the crystal structures.
MIGRATION OF THE ELECTRONIC EXCITATION ENERGY IN LANGMUIR – BLODGETT FILMS OF XANTHENE DYES
Authors: IBRAYEV N. Kh. , SATYABALDINA D. Zh. , ZHUNUSBEKOV A. M.
Published: July 2002

The concentration and temperature dependencies of the photophysical properties of three new amphiphilic xanthene dyes in the Langmuir-Blodgett (LB) films have been studied. The mechanisms of excitation-energy relaxation were discussed in terms of the excitons migration among energetically disordered monomers and the energy trapping by molecular aggregates. The experimental results were analyzed in view of carried out molecular mechanics and MO calcuations. Triplet states of eosin in the LB films were investigated. The observed nonexponential decay kinetics of delayed fluorescence (DF) and phosphorescence were analyzed in the framework of an annihilation model for both exchange and multipolar interactions.
ABSORPTION SPECTRA SIMULATION OF PERSISTENCE-TYPE CYANINE DYE AGGREGATES IN LB FILMS
Authors: VITUKHNOVSKY A. G. , LOBANOV A. N. , PIMENOV A. V. , YONEZAWA Y. , KOMETANI N.
Published: July 2002

Simulation of the absorption spectra of the 2D persistence-type molecular aggregates consisting of the combination of oxacyanine dye (S9) and thiacyanine dye (S11) is being considered. These aggregates are modeled by square matrix structure in the extended dipole approximation. The simulation takes into account the vector properties of the transitional dipole moment, its orientation, diagonal disorder and the composition of the aggregate. Good fit with the experiment is obtained for dipole tilt angle θ=40°, dipole moment μ=8.1 D and the disorder parameter of 450 cm -1 for various molar fractions of dyes.