bluuebunny/crossref_metadata_2025 huggingface dataset:
1‐Aryl‐3‐(dimethylamino)propenones: Strong Proton Acceptors for Hydrogen Bonds
Authors: Pleier Anna‐Katharina , Herdtweck Eberhardt , Mason Sax A. , Thiel Werner R.
Published: May 2004

Because of the electron‐donating effects of their terminal dimethylamino groups, the carbonyl units of 1‐aryl‐3‐(dimethylamino)prop‐2‐en‐1‐ones are excellent proton acceptors. Intra‐ and intermolecular hydrogen bonds formed by these species were investigated by structural techniques (X‐ray and neutron diffraction), spectroscopy, and density functional calculations. Co‐crystallization of a derivative bearing three (dimethylamino)prop‐2‐en‐1‐one units attached at one center in the presence of different proton donors produced one‐ and two‐dimensional H‐bridged polymers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis of Novel 2‐O,3′‐N‐Linked Macrocyclic Taxoids with Variable Ring Size
Authors: Querolle Olivier , Dubois Joëlle , Thoret Sylviane , Dupont Christophe , Guéritte Françoise , Guénard Daniel
Published: May 2004

A series of macrocyclic taxoids was prepared by connecting the 2‐OH and 3′‐NH moieties with aliphatic chains to mimic the docetaxel solid‐state conformation. The synthesis was achieved by acylation of both positions with various bromoalkanoic acids, and ring closure was carried out with sodium sulfide. Nine 19‐ to 27‐membered macrocyclic taxoids were obtained and evaluated as inhibitors of microtubule disassembly as well as for their cytoxicity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
A New and Productive Route to 1‐Heteroarylcyclopropanols
Authors: Belov Vladimir N. , Savchenko Andrei I. , Sokolov Viktor V. , Straub Alexander , Meijere Armin de
Published: May 2004

(E/Z)‐2‐(1‐Allyloxycyclopropyl)‐3‐methoxyacrylonitrile (4‐All) was designed and prepared in five steps (58% overall yield) from ethyl cyclopropylidenacetate as a valuable precursor to various 1‐heteroarylcyclopropanols. Its condensation with amidines, guanidine, hydrazine, and methyl thioglycolate and subsequent removal of the allyl protecting group yields 1‐heteroarylcyclopropanols such as 1‐OH (36% over 2 steps), a very potent NO‐independent stimulator of soluble guanylate cyclase. Direct cleavage of the allyl ether protecting group [by palladium‐catalyzed substitution with lithium p‐toluenesulfinate in AcOH or treatment with c‐HexMgBr/Ti(OiPr)4] gives highly functionalized, sterically congested 1‐heteroarylcyclopropanols 29, 30, and 34 with intact amino and ester groups. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
4,15‐Diamino[2.2]paracyclophane as a Starting Material for Pseudo‐Geminally Substituted [2.2]Paracyclophanes
Authors: Shaieb Kamal El , Narayanan Vijay , Hopf Henning , Dix Ina , Fischer Axel , Jones Peter G. , Ernst Ludger , Ibrom Kerstin
Published: May 2004

Diazotization of the title compound 3, followed by treatment of the formed bis(diazonium ion) with cuprous chloride, yields the pseudo‐geminal dichloride 1. Similarly, 3 is converted into the bis(azide) 5 when sodium azide is used as the trapping nucleophile. Hypochlorite oxidation of 3 furnishes the azo compound 4, the first multi‐bridged cyclophane with a bridge consisting only of heteroatoms. Reduction of 4 with zinc/acetic acid affords the substrate 3 again. Treatment of 4 with bromine/iron powder or iodine monochloride causes deazotization accompanied by halogen introduction in pseudo‐geminal position (i.e., formation of 2 and 6, respectively). Flash vacuum pyrolysis (450 °C, 0.01 Torr) of 4 produces the phenanthrene derivatives 13 and 14, while with tetracyanoethylene (TCNE) the azophane undergoes rapid cycloaddition at room temperature to give the [2+4] cycloadduct 16. The structures of 1, 2, 4−6, and 16 have been determined by X‐ray structural analysis. Molecular packing patterns are determined by weak hydrogen bonds; a common packing pattern for cyclophane derivatives is ascribed to C−H···π interactions. Full bandshape analyses of the bridge proton signals in the 1H NMR spectra of 1, 2, 6, and of the difluoro analogue 17 yielded the vicinal 1H,1H coupling constants. These reflect the 1:1 equilibrium between the two skew conformations of the bridges. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Highly π‐Facial Stereoselective Aldol Reaction of (S)‐Proline‐Derived Amide Enolate with Benzaldehydes
Authors: Adam Waldemar , Zhang Aimin
Published: May 2004

The asymmetric aldol reaction of the (S)‐proline‐derived bicyclic amide enolate 1 with benzaldehydes selectively affords the two diastereomeric aldol adducts (3S,3′R,8S)‐3a and (3S,3′S,8S)‐3a, of four possible diastereomers, in good yield. The high control of π‐facial stereoselectivity at the endocyclic C‐3 stereocenter is due to perfect shielding by the pseudo‐axial phenyl ring at the C‐1 position. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Two‐phase estimation of coverages with second‐phase corrections
Authors: Fattorini L. , Marcheselli M. , Pisani C.
Published: May 2004

A two‐phase estimation of coverages of the k land categories partitioning a study area is considered. In the first phase a sample of N points is selected according to a spatial sampling design and the selected points are assigned to the k categories on the basis of satellite imagery or aerial photos. Simple random sampling, stratified sampling and systematic sampling of points are considered. The theoretical results suggest the use of stratified sampling as the best design‐based spatial strategy in the first phase. Subsequently, in the second phase, a sample of n < N points is selected using a finite population sampling design. Then the selected points are visited and correctly classified on the ground. To this purpose, a stratified sampling is considered in which the strata are determined by the aerial classification. The statistical properties of the resulting two‐phase estimator are derived and a conservative estimator of its variance–covariance matrix is proposed. The procedure is checked on the basis of a simulation study performed on some artificial populations. Copyright © 2004 John Wiley & Sons, Ltd.
Nonlinear estimation for PM2.5 transmission effects in Jefferson Co., Texas
Authors: Eun Kim Sung
Published: May 2004

Urban air pollution consists of emission and transmission of air pollutants. In this article, we discuss a complex valued nonlinear regression model to characterize the effect of pollutant transmission by estimating the direction and velocity of the spatial propagation at a fixed sequence of time intervals. In case the pollutant is transmitted from a distant source during a certain time period, the monitoring stations in the local network detect the signal with time delays, which are nonlinearly related to the velocity and angle of approach or azimuth. An observed vector time series in the monitoring network is modeled as the sum of a lagged or delayed stochastic signal and a zero mean stationary noise vector. The Fourier transformation is applied to the model, and the maximum likelihood estimation of the transmission parameters under such a model is considered. Those estimates can be used to identify the possible sources of local pollutants and for better understanding of spatial distribution of pollutants. Data used in this study are based on hourly PM2.5 records from three monitoring stations in the Beaumont‐Port Arthur area in Texas for April to December 2002. The results indicate that during the months May, November and December, PM2.5 transmission were significant, with the dominant direction from the east. The velocity estimates during the period range from 4 to 20 km/h. During the summer season (June to October) the transmission effect was not very evident except for the first week of August and the first week of September. The model well detects both consistent and momentary transmissions. The parameter estimates and their standard errors are given for each week separately. Copyright © 2004 John Wiley & Sons, Ltd.
Survey of Protozoa and Metazoa populations in wastewater treatment plants by image analysis and discriminant analysis
Authors: Amaral A. L. , da Motta M. , Pons M. N. , Vivier H. , Roche N. , Mota M. , Ferreira E. C.
Published: May 2004

The biota present in the activated sludge of a wastewater treatment plant are mainly composed of bacteria, Protozoa and Metazoa. The Protozoa and Metazoa species are important micro‐organisms taking part in the ecosystem balance in wastewater treatment plants and are quite sensitive to physical, chemical and operational processes. Several authors have established relationships between the predominance of certain species or groups and some variables of the plant. Such analysis demands the identification and quantification of the different species, which requires skilled workers, specializing in zoology or protozoology, and is time‐consuming. To overcome those problems, semi‐automatic image analysis and discriminant analysis were carried out for the identification procedures. The overall results were very promising in terms of Protozoa and Metazoa group recognition and of survey of plant conditions. Copyright © 2004 John Wiley & Sons, Ltd.
Transient analysis of HVDC power transmission systems
Authors: Abdel‐Salam M. , Seddik H.
Published: May 2004

This paper describes a method for dynamic simulation of HVDC transmission systems based on transient circuit analysis during abnormal conditions. Such conditions include sudden drop or rise in the AC system voltage at the rectifier or inverter sides and short‐circuit faults on the DC link. The waveforms of the calculated DC current and terminal voltages of the DC link agreed reasonably with those reported before. The accuracy of the simulation method is also checked during normal operating conditions. For different short‐circuit faults on the DC link a conventional third‐order controller is proposed (for the first time) to reduce the DC current to its normal level in a more efficient way than the first‐order controller being used before. Copyright © 2004 John Wiley & Sons, Ltd.
Order of genetic events is critical determinant of aberrations in chromosome count and structure
Authors: Fauth Christine , O'Hare Michael J. , Lederer Gabi , Jat Parmjit S. , Speicher Michael R.
Published: May 2004

A sequential acquisition of genetic events is critical in tumorigenesis. A key step is the attainment of infinite proliferative potential. Acquisition of this immortalization requires the activation of telomerase in addition to other activities, including inactivation of TP53 and the retinoblastoma family of tumor‐suppressor proteins. However, the importance of the order in which these genetic events occur has not been established. To address this question, we used a panel of normal mammary fibroblasts and endothelial cultures that were immortalized after transduction with the catalytic subunit of telomerase (hTERT) and a temperature‐sensitive mutant of the SV40 large‐tumor (tsLT) oncoprotein in different orders in early‐ and late‐passage stocks. These lines were maintained in continuous culture for up to 90 passages, equivalent to >300 population doublings (PDs) post‐explantation during 3 years of continuous propagation. We karyotyped the cultures at different passages. Cultures that received hTERT first followed by tsLT maintained a near‐diploid karyotype for more than 150 PDs. However, in late‐passage stocks (>200 PDs), metaphase cells were mostly aneuploid. In contrast, the reverse order of gene transduction resulted in a marked early aneuploidy and chromosomal instability, already visible after 50 PDs. These results suggest that the order of genetic mutations is a critical determinant of chromosome count and structural aberration events. © 2004 Wiley‐Liss, Inc.
Assessing the reliability of density functional methods in the conformational study of polypeptides: The treatment of intraresidue nonbonding interactions
Authors: Improta Roberto , Barone Vincenzo
Published: May 2004

The role of intraresidue interactions in determining the conformational behavior of polypeptides is analyzed by means of density functional and post‐Hartree–Fock computations on the alanine dipeptide analog and other model compounds. Our computations show that the accuracy of current density functionals is sufficient for H‐bond, electrostatic, inductive, and short‐range repulsive interactions, whereas medium‐range attractions between electron‐rich atoms and/or bonds are underestimated. This leads, in turn, to an underestimation of the stability of helical structures w.r.t. extended or folded conformers involving H‐bonds. Those results could pave the route for devising local ad hoc corrections able to significantly improve structural and dynamic predictions for polypeptides issuing from DFT computations. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1333–1341, 2004
In‐line mixing for production of citric acid byCandida lipolyticagrown onn‐paraffins
Authors: Crolla A , Kennedy KJ
Published: May 2004

This study reports on the effects of internal fermenter and external in‐line agitation and fed‐batch mode of operation on citric acid production fromCandida lipolyticausingn‐paraffin as the carbon source. An optimum range of fermenter agitation speeds in the range 800–1000 rpm corresponding to Reynolds numbers of 50433–62947 (based on initial batch conditions) seemed to give the best balance between substrate utilization for biomass growth and citric acid production. Proof of concept evidence is presented that indicates that an external in‐line agitator could be used in place of high speed internal agitation to increase citric acid production. However, more work is required to optimize the external agitator concept. Application of multiple fed‐batch feedings can be used to extend the batch fermentation and increase final citric acid concentrations and product yield. Experiments were conducted implementing a three‐cycle fed‐batch process which increased overall citric acid yields to 0.8–1.0 g citric acid g−1n‐paraffin, approximately 200% improvement from those found in the normal batch process. The three‐cycle fed‐batch mode of operation also increased the final citric acid concentration to 42 g dm−3from about 6 g dm−3for normal batch operation. Increased citric acid concentrations in three‐cycle fed‐batch mode was achieved at longer fermentation times. Copyright © 2004 Society of Chemical Industry
The specificity and the ability ofAspergillusferuloyl esterase to releasep‐coumaric acid from complex cell walls of oat hulls
Authors: Yu Peiqiang , McKinnon John J , Maenz David D , Racz Vern J , Christensen David A
Published: May 2004

p‐Coumaric acid (4‐hydroxycinnamic) and ferulic acid (4‐hydroxy‐3‐methoxycinnamic), two major hydroxycinnamic acids found in the complex cell walls of oat hulls, act as cross‐linking agents between lignin and polysaccharides or between polysaccharides. As such, they are inhibitory to the biodegradation of cell walls by microorganisms. A previous study showed thatAspergillusferuloyl esterase withTrichodermaxylanase was able to break the ester linkage between ferulic acid and the attached sugar, releasing ferulic acid from the cell wall. The objective of this study was to investigate the specificity and the ability ofAspergillusferuloyl esterase to releasep‐coumaric acid from oat hulls. The results show there was no extensive release ofp‐coumaric acid in both the absence and presence ofTrichodermaxylanase byAspergillusferuloyl esterase. This indicates a specificity ofAspergillusferuloyl esterase, which is more active only on esters of certain hydroxycinnamic acids; in this case,Aspergillusferuloyl esterase will only sufficiently break the ester‐linked feruloyl group but not thep‐coumaroyl group in the complex cell walls of oat hulls. Copyright © 2004 Society of Chemical Industry
The effects of nitrate and nitrate‐supplemented leachate addition on methanogenesis from Municipal Solid Waste
Authors: El‐Mahrouki Iman Mohamed Lotfy , Watson‐Craik Irene Ann
Published: May 2004

The recirculation of nitrified leachate through landfill sites, followed by in situ denitrification, represents a novel and more sustainable approach for the removal of ammonia from leachate, prior to discharge. The effects of nitrate and leachate supplementation on methanogenesis in Municipal Solid Waste (MSW) were studied in batch cultures. The addition of a range of nitrate concentrations to MSW samples had an inhibitory effect on methanogenesis. The effects were dose‐dependent, such that recovery of methane production was recorded within 5 and 23 days with added 100 and 750 mg NO3 dm−3, respectively. Even after 24 days, no recovery was observed in cultures challenged with 1000 mg NO3 dm−3. The enumeration of denitrifying bacteria in a range of fresh, actively methanogenic and aged, well‐decomposed MSW confirmed the potential of MSW for rapid denitrification. Methanogenesis was not inhibited by the addition of leachate (20–100% strength) that contained high concentrations of VFAs. However, when the same leachate was supplemented with nitrate (250 mg NO3 dm−3), methanogenesis was inhibited by the addition of leachate concentrations ≥20%, which was attributed to inhibition of denitrification by VFAs. Propionate accumulated, confirming the importance of methanogenesis as an electron sink. With the removal of nitrate and the recovery of methanogenesis, net propionate concentrations decreased. Copyright © 2004 Society of Chemical Industry
Determination of fungicide residues in fruits by coupled‐column liquid chromatography
Authors: Zamora Tatiana , Hidalgo Carmen , López Francisco J. , Hernández Félix
Published: May 2004

Coupled‐column liquid chromatography with fluorescence detection was applied to the determination of o‐phenylphenol and bitertanol residues in orange and banana fruits. After extraction with a mixture of acetone, dichloromethane‐petroleum ether, and ethyl acetate, an extract aliquot of 100 μL was injected directly without any additional clean‐up into the chromatographic system using two reversed phase C18 coupled columns. The LC‐LC approach allowed automated sample clean up of the vegetal extracts, leading to a simple and rapid analytical procedure, with limits of quantification between 0.01 and 0.05 mg kg–1. Recovery experiments performed on orange and banana samples fortified at different concentrations (0.01–4 mg kg–1) gave average recoveries between 70 and 113% with relative standard deviations lower than 15%. The procedure developed was finally applied to orange and banana samples from different geographical locations and the results were confirmed by GC‐MS.
Time‐resolved luminescence of terbium complexes with poly(2‐ and 4‐vinylpyridine N‐oxide)s in aqueous solution
Authors: Výprachticky Drahomír , Cimrová Věra , Okamoto Yoshi , Kotva Rudolf
Published: May 2004

Terbium complexes with polymer ligands of poly(2‐ and 4‐vinylpyridine N‐oxide)s (P2VPNO, P4VPNO) in aqueous solution were prepared and characterized. Multi‐exponential decays of the 5D4 → 7F5 terbium transition at 545 nm of [P2VPNO‐Tb3+] and [P4VPNO‐Tb3+] complexes were measured. The non‐linearity of semi‐logarithmic plots of time‐resolved luminescence was more pronounced in [P4VPNO‐Tb3+] than in [P2VPNO‐Tb3+], being reduced by addition of salts such as sodium formate or acetate. We assume that multi‐exponential decays of Tb3+ in the complexes are caused by a back metal‐to‐ligand energy transfer via triplet state of N‐oxide polymer ligand. By carrying out separate experiments in water and deuterium oxide, the number of coordinated water molecules in the [P4VPNO‐Tb3+] complex was estimated as 4‐5, assuming that the Tb3+ aqua complex contains nine water molecules.
Physical properties and structure of thin conducting ion‐beam modified polymer films
Authors: Guenther Margarita , Gerlach Gerald , Suchaneck Gunnar , Schneider Dieter , Wolf Bodo , Deineka Alexander , Jastrabik Lubomir
Published: May 2004

In this work, a complex investigation of the film surface composition, chemical bonding, conductivity, optical properties, density, hardness and Young's modulus of ion‐beam‐modified polyimide films was carried out. It was shown that the partial destruction of chemical bonding under ion bombardment leads to the formation of graphite‐like, amorphous carbon islands, which increase the surface film conductivity by several orders of magnitude, from an insulating to a semiconducting region. Strong enhancements of both the conductivity and the optical absorption coefficient occur when the fraction of amorphous carbon clusters dispersed in a polyimide matrix reaches 40 %. The values of hardness, Young's modulus and density at high irradiation doses reach the values typical of a hydrogenated amorphous carbon.
Growth of organic n‐conductors on thin polymer films for use in organic field effect transistors
Authors: Michaelis W. , Kelting C. , Hirth A. , Wöhrle D. , Schlettwein D.
Published: May 2004

Thin films of different polymers ‐ poly(styrene) (PS), poly(methylmethacrylate) (PMMA), poly(vinylcarbazole) (PVCz), poly(vinylchloride) (PVC) and poly(vinylidene fluoride) (PVDF) ‐ were deposited by spin‐coating or by vapor deposition. On these polymers, thin films of (hexadecafluorophthalocyaninato)‐oxovanadium (F16PcVO) were prepared by physical vapor deposition. The growth of these films was monitored in situ by optical spectroscopy. The optical absorbance spectra were analyzed based on the coupling of transition dipoles to obtain information on the intermolecular arrangement of chromophores in the films. In all of these samples, the molecules are oriented with their molecular plane preferentially perpendicular to the substrate surface. This gives the desired overlap of the π‐systems for electric conductance parallel to the substrate. Differences in the interactions were detected when deposition temperatures below or above the glass transition temperature of a given polymer were compared. The morphology of the polymer films and the deposited semiconductors were investigated by atomic force microscopy and scanning electron microscopy. The influence of the chosen substrate on the film structure is determined. The optical and electric properties of the films could thereby be influenced and the applicability of such films as active layers in organic thin film transistors is discussed.
Quantum chemical study of oxidation processes in Cu‐phthalocyanine
Authors: Toman Petr , Nešpůrek Stanislav , Yakushi Kyuya
Published: May 2004

Quantum chemical calculations reproduced quite well the experimental infrared spectra of CuPc and CuNO3Pc · HNO3. The agreement in the changes of line intensities during the oxidation supports the idea of ligand oxidation. This result is in agreement with the Mulliken population analysis.
Atmospheric aging of poly[methyl(phenyl)silanediyl] monitored by FTIR spectroscopy
Authors: Meszároš Oto , Schmidt Pavel , Pospíšil Jan , Nešpůrek Stanislav , Kelnar Ivan
Published: May 2004

Poly[methyl(phenyl)silanediyl] films were irradiated in ATLAS Weather‐O‐Meter Ci 3000+ for ca 3 h. Changes in the region of siloxane, carbonyl, hydroxyl, and C‐H (aromatic) bands were monitored by FTIR. Main attention was paid to changes in siloxane formation, which could be reduced in the presence of phenolic UV absorber 1 and oxalanilide 3.
Hybrid organic‐inorganic coatings and films containing conducting polyaniline nanoparticles
Authors: Špírková Milena , Stejskal Jaroslav , Prokeš Jan
Published: May 2004

Hybrid organic‐inorganic coatings and free‐standing films made from [3‐(glycidyloxy)propyl]trimethoxysilane, amino‐terminated poly(oxypropylene) (Jeffamine D‐230), colloidal polyaniline nanoparticles and, in some cases, colloidal nanosilica were prepared and characterized. HCl or 4‐methylbenzene‐1‐sulfonic acid were used as catalysts for the sol‐gel process and pH tuning, water‐propan‐2‐ol mixture as a solvent. Electrical and mechanical properties and surface morphology of films were studied. The coatings were blue and non‐conducting, or green and conducting, depending on preparation conditions. They have a smoother surface than in‐situ polymerized polyaniline films.
Effect of a dipolar self‐assembly monolayer formation on indium‐tin oxide on the performance of single‐layer polymer‐based light‐emitting diodes
Authors: Morgado Jorge , Charas Ana , Barbagallo Nunzio , Alcácer Luis , Matos Manuel , Cacialli Franco
Published: May 2004

We report on the use of indium‐tin oxide surface modification, by grafting of highly polar p‐disubstituted benzenes, in the fabrication of light‐emitting diodes. The polar compounds possess COCl or SO2Cl grafting groups and CF3 or NO2 as highly electronegative groups, leading to the formation of a dipolar monolayer, which brings about an increase in ITO work function, thereby reducing the barrier for hole injection into luminescent polymers. We observe that the effect of this self‐assembled monolayer, in terms of light‐onset voltage, efficiency and luminance, is at least comparable to the use of a hole injection layer of doped poly[(3,4‐ethylenedioxy)thiophene] for LEDs using poly({2‐[(2‐ethylhexyl)oxy]‐5‐methoxy‐1,4‐phenylene}vinylene) (MEH‐PPV) and polyfluorene blends as active layers.
Coherent electronic transport through the single‐walled carbon nanotubes
Authors: Babiaczyk W. Iwo , Bułka Bogdan R.
Published: May 2004

We present the results for coherent electronic transport through the single walled carbon nanotubes. A large value of conductance is obtained for strong coupling to the electrodes, which is close to the ideal transmission of 4e2/h as in experiment. We also consider the system with ferromagnetic electrodes and analyze in detail conductance for separated channels in the coherent regime.
End‐functionalized π‐conjugated oligomeric materials for photoelectrical applications
Authors: Pavlík Martin , Pfleger Jiří , Jossifov Christo , Vohlídal Jiří
Published: May 2004

Soluble poly(diphenylacetylene)s (PDA) capped with PhCO‐ groups (PDA‐C) and Ph2C= groups (PDA‐P) were prepared via McMurry reductive coupling of benzil and carbonyl‐olefin exchange reaction of tetraphenylethene and benzil, respectively. Fluoren‐9‐ylidene groups have been introduced into PDA by the McMurry coupling of PDA‐C with fluoren‐9‐one and via copolymerization of benzil and fluoren‐9‐one. The oligomers prepared are stable in air, soluble in a variety of solvents. They can be processed by casting to form good‐quality thin films suitable for measurements of electrical and optoelectrical properties.
Comparative study of photodegradation and metastability in solution‐processed and plasmatic polysilylenes
Authors: Schauer F. , Dokoupil N. , Horváth P. , Kuřitka I. , Nešpůrek S. , Pospíšil J.
Published: May 2004

This study deals with photodegradation and metastability of polysilylenes. Physical properties of chemically prepared poly[methyl(phenyl)silylene] and polysilylenes prepared in radio‐frequency and microwave discharges are compared. The position and width of the photoluminescence band due to the main chain excitations for both materials preserve but its intensity strongly depends on the preparation conditions and changes considerably during the photodegradation. The difference in photodegradation rate of both materials is explained by their different susceptibility to silyl radical formation and reverse recombination due to the chain and side groups rigidity.
Facile synthesis of exfoliated and highly conductive poly(arylene disulfide)/graphite nanocomposites
Authors: Du X. S. , Xiao M. , Meng Y. Z. , Hay A. S.
Published: May 2004

Exfoliated graphite has been synthesized by first synthesizing H2SO4 intercalated compound in a H2O2‐H2SO4 mixture, followed by exfoliation under microwave irradiation. Poly(arylene disulfide)/graphite nanocomposites were then fabricated by absorbing cyclic(arylene disulfide) oligomers into the pores of exfoliated graphite. Subsequently, the nanocomposite precursor was subjected to heat treatment to carry out the in situ ring‐opening polymerization of the oligomers via free radical mechanism. The as‐prepared nanocomposite exhibited a exfoliated nanostructure as evidenced by transmission electron microscopy (TEM) observation. The nanocomposite with a very small amount of graphite, 5 wt%, possesses a highly electrical conductivity of 4 S/cm, therefore, many applications can be found as conductive materials. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis of thermally crosslinkable fluorine‐containing poly(arylene ether ketone)s—II. Propargyl ether terminated poly(arylene ether ketone)s
Authors: Kimura Kunio , Nishichi Ai , Yamashita Yuhiko
Published: May 2004

Novel thermally crosslinkable fluorine‐containing poly(arylene ether ketone)s comprised of 2,3,5, 6‐tetrafluoro‐1,4‐phenylene moiety were synthesized by the termination of polymer chain ends with propargyl ether groups in order to improve solvent resistance. Crosslinking reaction occurred over 250°C through the formation of both chromen ring and polyene structure. This structure change brought about not only the outstanding solvent resistance but also the increase in glass transition temperature (Tg). The cured films also exhibited excellent thermal stability, transparency and hydrophobicity derived from fluorine atoms. Copyright © 2004 John Wiley & Sons, Ltd.
Mechanical, thermal and morphological properties of poly(ε‐caprolactone)/zein blends
Authors: Corradini E. , Mattoso L. H. C. , Guedes C. G. F. , Rosa D. S.
Published: May 2004

Blends of poly(ε‐caprolactone) (PCL) with zein (PCL/zein) in different proportions (100/0, 75/25, 50/50, 25/75 and 0/100 wt% containing 5 wt% glycerol) were compared based on their mechanical properties (tensile strength, elongation at break, and Young's modulus), and on their thermal properties, the latter determined by thermogravimetric analysis (TGA) and dynamic mechanical thermal analysis (DMTA). The morphology of the materials was studied by scanning electron microscopy (SEM). Blends of PCL/zein showed reduced tensile strength and elongation at break, but increased Young's modulus compared to the pure polymers, in agreement with the DMTA and SEM results. These findings indicated that PCL and zein were incompatible. TGA showed that the thermal stability was enhanced by the addition of zein to PCL, whereas SEM showed a poor interfacial interaction between the polymers. Copyright © 2004 John Wiley & Sons, Ltd.
Prenatal overgrowth and mosaic trisomy 15q25‐qter including the IGF1 receptor gene
Authors: Faivre Laurence , Rousseau Thierry , Laurent Nicole , Gosset Philippe , Sanlaville Damien , Thauvin‐Robinet Christel , Cusin Véronica , Lionnais Stéphanie , Callier Patrick , Khau Van Kien Philippe , Huet Frédéric , Turleau Catherine , Sagot Paul , Mugneret Francine
Published: May 2004

Overgrowth is rarely associated with chromosomal imbalances. Here, we report on a male foetus presenting with overgrowth and additional material on the short arm of one of the chromosome 15 in 12% of lymphocytes and 50% of amniotic cells. Parents' karyotypes were normal, indicating a de novo origin for this unbalanced rearrangement. Complementary studies using cytogenetic and FISH studies showed that this additional material resulted in a 15q25‐qter trisomy and confirmed the presence of three copies of the insulin‐like growth factor 1 receptor (IGF1R) gene, included in the trisomic region. Autopsy performed after termination of pregnancy revealed isolated overgrowth and absence of visceral malformations. The possible mechanisms and origins for the formation of this mosaic pure trisomy are complex. The present observation emphasises the hypothesis that the overgrowth phenotype, frequently reported in patients with trisomy including the 15q26 region, might be causally related to a dosage effect of the IGF1R gene, as well as the importance of chromosome analysis in patients with overgrowth. It also confirms that the overgrowth is of prenatal onset in those observations. Copyright © 2004 John Wiley & Sons, Ltd.
High frequency of use of rofecoxib at greater than recommended doses: cause for concern
Authors: Griffin Marie R. , Stein C. Michael , Graham David J. , Daugherty James R. , Arbogast Patrick G. , Ray Wayne A.
Published: May 2004

Purpose

To determine the prevalence of chronic use of rofecoxib 50 mg. Rofecoxib is unusual among nonsteroidal anti‐inflammatory drugs (NSAIDs) in that the licensed dose for acute pain is double the maximum dose recommended for chronic use. The 50 mg dose is recommended for acute pain only, for a maximum of 5 days. In clinical trials of chronic use for arthritis, hypertension was more frequent in patients assigned 50 mg rofecoxib than in those assigned lower doses or other NSAIDs. Thus chronic use of high doses of rofecoxib has implications for patient safety.

Methods

Cross‐sectional analysis of the prevalence of chronic use of rofecoxib 50 mg in 2001, among persons aged ≥50 years, enrolled in the Tennessee Medicaid program.

Results

On 1 July 2001, 14% of the study population had a current prescription for an NSAID, with a supply of pills for >5 days. Of all NSAID prescriptions, 25% were for rofecoxib, and 17% of these prescriptions were for >25 mg daily. Of those prescribed >25 mg daily, 71% filled prescriptions for at least 50 mg for 30 days. In this latter group, 60% and 69% filled another rofecoxib prescription within 1 and 2 weeks, respectively, of the end of their 30 days supply. Demographics and co‐morbid conditions of high dose rofecoxib users did not differ substantially from users of other NSAIDs or the total population.

Conclusion

Use of rofecoxib 50 mg for >5 days is relatively common. In view of dose‐related adverse effects, such use should be discouraged. Copyright © 2003 John Wiley & Sons, Ltd.
Introducing triage logic as a new strategy for the detection of signals in the WHO Drug Monitoring Database
Authors: Ståhl M. , Lindquist M. , Edwards I. R. , Brown E. G.
Published: May 2004

Purpose

An important role for the WHO Programme for International Drug Monitoring is to identify signals of international drug safety problems as early as possible. The signal detection strategy, operated at the Uppsala Monitoring Centre (UMC), gave too many drug–adverse drug reaction (ADR) combinations for individual review. Therefore additional selection strategies were needed to improve the likely signal‐to‐noise ratio and for the UMC to complement the efforts of national centres in an efficient way.

Methods

The combinations database of the first quarter of 2001 was analysed using algorithms representing different strategies for finding relevant signals using triage logic.

Results

The strategies that together gave a manageable number of combinations, i.e. around 600, for further consideration in a single quarter were the algorithms for ‘Rapid reporting increase’, ‘Serious reaction and new drug’ and ‘Special interests’. These filters began to be used routinely on the combinations database in late 2001.

Conclusions

While stressing that human review is essential, triage strategies are useful when attempting analysis of large amounts of data. By definition, the use of triage strategies may exclude some potential signals from consideration, although the intention is to improve the chances of detection by focussing on areas of greatest importance. Copyright © 2004 John Wiley & Sons, Ltd.
Factors related with prescription requirement to dispense in Spain
Authors: Caamaño Isorna Francisco , Tomé‐Otero Manuel , Takkouche Bahi , Figueiras Adolfo
Published: May 2004

Purpose

To identify factors associated with prescription requirement to dispense.

Methods

We carried out a cross‐sectional study on a sample of 166 pharmacists in North‐West Spain. The following independent variables were collected through a personal interview: pharmacist's education and speciality, characteristics of the pharmacy, and its socio‐economic environment. We constructed multiple regression models using as dependent variables: requirement of prescription to dispense five drugs which have to be dispensed with a prescription; and opinion on whether a prescription should be required to dispense these drugs.

Results

The response rate was 98.8%. A proportion of 65.9% of pharmacists dispense antibiotics without any prescription. This proportion is 83.5% for nonsteroidal anti‐inflammatory drugs, 46.3% for ACE inhibitors, 13.4% for benzodiazepines and 84.8% for oral contraceptives. A higher requirement prescription was found to be associated with the antecedent of a speciality training of the pharmacist (p = 0.028) and his or her age (p < 0.001). A low prescription requirement is associated with the condition of being owner of the pharmacy (p = 0.032), with a high economic level of the population attended (p = 0.016) and with the size of the pharmacy (p = 0.045).

Conclusions

The proportion of pharmacists who dispense drugs without a prescription is extremely high. Our results suggest that in order to increase quality of dispensing, it is necessary to increase pharmacist education and direct efforts of awareness primarily at pharmacists in charge, who are young and work in large pharmacies. Copyright © 2003 John Wiley & Sons, Ltd.
Refill rate of antipsychotic drugs: an easy and inexpensive method to monitor patients' compliance by using computerised pharmacy data
Authors: Rijcken C. A. W. , Tobi H. , Vergouwen A. C. M. , de Jong‐van den Berg L. T. W.
Published: May 2004

Purpose

In the literature, noncompliance to medication in patients with schizophrenia ranges from 20 to 89%. There is an urgent need for reliable and valid techniques that measure compliance in antipsychotic drug treatment. In this study, we use pharmacy‐dispensing records to assess compliance by calculating the refill rate of antipsychotic medication.

Methods

Refill rates of chronic antipsychotic drug users in 1999 and in 2000 were established by dividing the number of prescribed days by the total number of calendar days that the patient was registered in a pharmacy prescription records database.

Results

More than 50% of patients using an antipsychotic drug show a refill rate that is associated with medication compliance (0.9–1.1). The number of daily antipsychotic drug intakes was associated with a divergent refill rate, more than once daily dosing was associated with a significantly elevated refill rate (p < 0.015).

Conclusions

The refill rate is a valuable addition to the small arsenal of objective compliance measurement tools. It is an easy to obtain and inexpensive way to estimate (non)compliance. We recommend future studies to medication use in both mental and physical disorders, in order to further specify the actual value of refill rates in clinical practice. Copyright © 2004 John Wiley & Sons, Ltd.
Antibiotic utilization prevalence: prospective comparison between two medical departments in a tertiary care university hospital
Authors: Gendel Inna , Azzam Zaher S. , Braun Eyal , Levy Yshai , Krivoy Norberto
Published: May 2004

Purpose

The aim of this study was to analyze prospectively antibiotic utilization, comparing two in‐patient Internal Medicine units.

Methods

Data on individual antibiotic utilization pattern and antibiotic costs were collected prospectively from hospitalized patient charts over a 12‐month period, using the prescription‐point prevalence method twice a month, for a total of 24 encounters for each admission unit.

Results

The antibiotic volume/patient (number of prescriptions), using the prescription‐point prevalence methodology, was 330 and 557 in Internal Medicine B and D, respectively, resulting in 1.29 and 1.25 antibiotic courses/patient for each of the two units, respectively (p = 0.91). Thirty‐five percent and 39% of the patients received at least one anti‐microbial prescription. The total defined daily dose (DDD) and drug utilization 90% (DU90%) index for the units were 432.7 DDD, DU90% 389.7 and 727.8 DDD, DU90% 660.4, respectively (p = 0.01). The drug cost 90% index (DC90%) placed piperacillin–tazobactam in the first place in both units, while amoxycillin–clavulanic acid was in first place when the DU90% index was applied.

Conclusions

A significant statistical difference was found in the anti‐microbial cost analyzes of DDD, DU90% and DC90% indexes of the two units, using the prescription‐point prevalence methodology. The intervention of a clinical pharmacology specialist in one of the units was effective in reducing the costs registered in that unit. Copyright © 2004 John Wiley & Sons, Ltd.
Preface: phys. stat. sol. (b) 241/7
Authors: Shin Sung‐Chul
Published: May 2004

The KMS/SOMMA Meeting 2003 was held 3–6 December 2003 at Spapia Hotel, Daejeon, Korea. It was the 5th SOMMA (International Symposium on Magnetic Materials and Applications) organized by ReCAMM (Research Center for Advanced Magnetic Materials) of Chungnam National University. Since 2002, the Korean Magnetics Society (KMS) winter conference has been jointly held with SOMMA. This was the second time to have a KMS/SOMMA joint meeting.

The main objective of the meeting was to provide an international forum to discuss up‐to‐date results on magnetism and magnetic materials. The conference brought together 360 participants from 12 countries. Sessions of the meeting were: Theory and Fundamentals, Magnetic Random Access Memory, Spintronics, Information Storage, Nanostructured Materials, Sensors, and Interdisciplinary. In these seven sessions, 325 papers were presented including 66 oral and 259 poster presentations. Since the symposium was held in Korea, this enabled a large number of Asian scientists to attend: 239 from Korea, 41 from Japan, 7 from Taiwan, and 5 from China.

The conference program had 25 invited and plenary speakers. They were Y. Ando (Tohoku U.), M. Inoue (Toyohashi U. Tech), H. Kubota (Tohoku U.), K. Mohri (Nagoya U.), M. Sahashi, M. Takahashi, K. Takanashi, M. Tsunoda (Tohoku U.), and H. Yoda (Toshiba) from Japan; A. J. Freeman (Northwestern U.), A. T. Hanbicki (NRL), F. B. Humphrey (Boston U.), and S. Sun (IBM) from the USA; J. D. Boeck (IMEC, Belgium), B. Dieny (CEA, France), N. Garcia (CSIS, Spain), G. Reiss (Bielefeld U., Germany), T. Stobiecki (U. M. & M. Krakow, Poland), and M. Wolfram (Singulus Tech, Germany) from Europe; C. G. Kim, D. J. Kim (CNU), T. W. Kim (SAIT), S. H. Lim (KIST), Sung‐Chul Shin (KAIST), and Yoon Hee Chung (POSTEC) from Korea.

For the first time, the SOMMA Proceedings appear in physica status solidi. The Editors hope that the Proceedings could provide chances for deeper and wider understanding of the presentations as well as for enhanced relationship between all participants. We deeply appreciate the help of the editorial staff of physica status solidi for their efficient and kind help during the paper preparations and publications.

Finally, we would like to take this opportunity to thank all members of the Advisory Committee, Organizing Committee, referees, and KMS staff for their effort before, during, and after the meeting.
Sample sizes for clinical trials with Normal data
Authors: Julious Steven A.
Published: May 2004

This article gives an overview of sample size calculations for parallel group and cross‐over studies with Normal data. Sample size derivation is given for trials where the objective is to demonstrate: superiority, equivalence, non‐inferiority, bioequivalence and estimation to a given precision, for different types I and II errors. It is demonstrated how the different trial objectives influence the null and alternative hypotheses of the trials and how these hypotheses influence the calculations. Sample size tables for the different types of trials and worked examples are given. Copyright © 2004 John Wiley & Sons, Ltd.
Latitudinal and seasonal variations of quasiperiodic and periodic VLF emissions in the outer magnetosphere
Authors: Engebretson M. J. , Posch J. L. , Halford A. J. , Shelburne G. A. , Smith A. J. , Spasojević M. , Inan U. S. , Arnoldy R. L.
Published: May 2004

We have analyzed ELF‐VLF receiver and search coil magnetometer data from five Antarctic stations from 1998 and 1999 to study quasiperiodic emissions (QPs) and periodic emissions (PEs), which occur as ULF‐range modulations of ELF‐VLF signals between 0.5 kHz and ∼4 kHz. QPs are modulated at frequencies of ∼20–50 mHz, and PEs are modulated at frequencies of ∼200–500 mHz. The stations used covered a range of magnetic latitudes from −62° (Halley) to −74° (South Pole Station); three automated geophysical observatories (AGOs) were located at intermediate latitudes. Consistent with earlier studies, most QPs were observed with magnetic pulsations of identical period in the Pc3 range (type I QPs). Of those QPs not observed with simultaneous magnetic pulsations (type II QPs), nearly all were accompanied by PEs. Type I QPs, PEs, and events during which both appeared together (QPPEs) were found to have different latitudinal, seasonal, and diurnal occurrence patterns: QPs of both types were more likely to occur between −65° and −70° magnetic latitude, while PEs occurred more often around −60° magnetic latitude. QPs were more common during the months of October though March, while PEs were more common during the months of May through September. QPs, whether with or without simultaneous PEs or magnetic pulsations, were predominantly a dayside phenomenon, with a broad maximum near local noon. The occurrence of QPs unaccompanied by PEs was restricted to the dayside, however, while a small number of QPPEs appeared even during nighttime hours. PEs, on the other hand, could be seen at all local times, but with latitudinally dependent diurnal patterns. Most higher‐latitude QPs were type I events (observed with magnetic pulsations), while type II QP events (without simultaneous magnetic pulsations) occurred relatively more often at lower latitudes. A case study from 1 August 1999 using wideband data from South Pole and Halley provides evidence of a transition from echoing whistler activity to PE activity and then to QP activity and suggests a causal relationship.
Long wave dynamics of the interannual variability in a numerical hindcast of the equatorial Pacific Ocean circulation during the 1990s
Authors: Yuan Dongliang , Rienecker Michele M. , Schopf Paul S.
Published: May 2004

A numerical hindcast of the Pacific Ocean circulation for the period of 1988–1998 is conducted to study the dynamics of interannual variations in the 1990s. The Poseidon quasi‐isopycnal ocean model is forced with an SSMI‐derived wind stress product and sea surface heat flux from an atmospheric mixed layer model. On the basis of a good comparison of the hindcast results with TAO mooring observations, the roles of the propagation and reflection of the equatorial Kelvin and Rossby waves in the evolution of El Niño and La Niña events in the 1990s are investigated. The linear waves are extracted from the nonlinear model in such a way as to preserve model nonlinearity so that the validity of linear theory of the wave propagation and reflection at the western and eastern boundaries can be examined. It is found that the reflection of the Kelvin waves at the eastern boundary is in very good agreement with a linear reflection at a straight meridional wall. In contrast, the reflection of the Rossby waves at the Pacific western boundary is significantly different from linear theory. Besides the validation of linear theory, the decomposition also shows marked differences from altimetry data analyses. Since the hindcast solution is dynamically consistent and close to observations, a significant part of the differences is attributed to errors associated with the incomplete (least squares fit) wave decomposition from the altimetry data. On the basis of the wave decomposition, the dynamics of the simulated El Niño and La Niña events in the 1990s are compared with three ENSO paradigms. The investigation shows that precursive Rossby waves, important in the Delayed Oscillator paradigm, played an important role in the termination of the 1991–1993 and the 1997–1998 El Niño events. Reflected Rossby waves from the Pacific eastern boundary, the primary negative feedback in the Advective‐Reflective paradigm, were present during the termination of the 1994–1995 and the 1997–1998 El Niño. The Western Pacific Oscillator is at best at work during the decay of the 1997–1998 El Niño; however, it played a minor role compared with the other paradigms. None of the three paradigms appears to describe the termination of the 1988–1989 and the 1995–1996 La Niña events and the onset of the 1997–1998 El Niño event well.