bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antibiotics in pregnancy: analysis of potential risks and determinants in a large German statutory sickness fund population
Authors: Amann Ute , Egen‐Lappe Veronika , Strunz‐Lehner Christine , Hasford Joerg 
Published: March 2006

AbstractPurposeAntibiotics are frequently prescribed drugs in pregnancy. The purpose of the study was to analyse the use, the potential risks and the determinants of systemic antibiotic prescriptions during pregnancy.MethodsA large, nation‐wide acting German statutory sickness fund provided prescription data and personal data of 41 293 pregnant women. For this study, all prescriptions of systemic antibiotics (ATC: J01) dispensed to each woman during a 21‐month period were analysed. We used the FDA risk classification system and enrolled a literature search to identify potentially harmful antibiotics. To investigate the impact of geographical and socio‐economic determinants in antibiotic prescribing, a multivariate logistic regression model was performed.ResultsOf the 41 293 women, 19.7% received at least one antibiotic drug during pregnancy. There was a shift to relatively safe and reduced antibiotic drug use during pregnancy. Prescribing of contraindicated antibactericals or potentially harmful drugs was seen in 521 women (1.3% of all women). In the logistic regression, being younger than 21 years (adjusted OR 2.14, 95%CI 1.80–2.53) or being welfare recipient (adjusted OR 1.57, CI 1.25–2.00) was strongly associated with higher antibiotic use. Significantly lower antibiotic use was seen in 5 of 16 German federal states (OR 0.74–0.83).ConclusionsAbout 20% of pregnant women received antibiotics, and 1.3% received a harmful drug. To minimise the risks, detailed guidelines are needed for the antibiotic treatment during pregnancy. Copyright © 2006 John Wiley & Sons, Ltd.
Novel organosoluble and colorless poly(ether imide)s based on 3,3‐bis[4‐(3,4‐dicarboxyphenoxy)phenyl]phthalide dianhydride and aromatic bis(ether amine)s bearing pendent trifluoromethyl groups
Authors: Yang Chin‐Ping , Su Yu‐Yang 
Published: March 2006

AbstractA novel series of colorless and highly organosoluble poly(ether imide)s were prepared from 3,3‐bis[4‐(3,4‐dicarboxyphenoxy)phenyl]phthalide dianhydride with various fluorinated aromatic bis(ether amine)s via a conventional two‐stage process that included ring‐opening polyaddition to form the poly(amic acid)s followed by cyclodehydration to produce the polymer films. The poly(ether imide)s showed excellent solubility, with most of them dissoluble at a concentration of 10 wt % in amide polar solvents, in ether‐type solvents, and even in chlorinated solvents. Their films had a cutoff wavelength between 358 and 373 nm, and the yellowness index ranged from 3.1 to 9.5. The glass‐transition temperatures of the poly(ether imide) series were recorded between 237 and 297 °C, the decomposition temperatures at 10% weight loss were all above 494 °C, and the residue was more than 54% at 800 °C in nitrogen. These films showed high tensile strength and also were characterized by higher solubility, lighter color, and lower dielectric constants and moisture absorption than an analogous nonfluorinated polyimide series. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3140–3152, 2006
Quantum theory of symmetric screening in the Hartree approximation
Authors: Rusin Tomasz M. , Zawadzki Wlodek 
Published: March 2006

AbstractQuantum theory of screening by the electron gas is formulated in the Hartree approximation. The energy of interaction between two charges is calculated taking into account interaction between bare charges, interaction between the charges and the gas, interaction between the electrons in the gas, and finally the kinetic energy of the electron gas in the charges' field. It is assumed that both charges are screened symmetrically, the notion of a test charge is not employed. Our self‐consistent linear screening theory accounts for all second order corrections in the perturbing potentials. We get the known result that the interaction energy is obtained by multiplying the screened potential of the first charge by the bare second charge. However, our result comes about from a partial cancellation between the kinetic and potential parts of the interaction energy in the rigorously symmetric screening, whereas in the standard derivations it results from the asymmetric screening picture with the use of a test charge. The calculated structure of kinetic and potential parts of the interaction energy is discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Symmetry properties of ZnO nanorods and nanotubes
Authors: Tronc P. , Stevanovic V. , Milosevic I. , Damnjanovic M. 
Published: March 2006

AbstractThe symmetry of ZnO hexagonal nanorods and nanotubes depends on the location of their axes with respect to the ZnO wurtzite lattice. When the axis coincides with a threefold rotation axis of the lattice (type I structure), the point and space symmetries are described by the C3v point group and the R 49 (p3m1) rod group, respectively. When the axis coincides with a 63 improper rotation axis (type II structure), the symmetries are described by the C6v point group and the R 70 (p63mc) rod group, respectively. The site symmetry of an atom in the structure is C3v, Cs, or C1, depending on its location. At any point of the one‐dimensional Brillouin zone the direct optical transitions in the nanostructures obey the selection rules governed by the C3v group (type I) or the C6v one (type II). The latter group is that of the Γ point of bulk ZnO. The rules for transitions involving bound states differ from those in the bulk since generally they are governed by smaller groups. The effect of a magnetic or/and an electric field on the symmetry properties of the nanostructures is established. The symmetry of heterostructures located along a single nanorod or nanotube is determined. The envelope function approximation is considered. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Efficient and reliable method for the simulation of scanning tunneling images and spectra with local basis sets
Authors: Paz Óscar , Soler José M. 
Published: March 2006

AbstractBased on Bardeen's perturbative approach to tunneling, we have found an expression for the current between tip and sample, which can be efficiently coded in order to perform fast ab initio simulations of STM images. Under the observation that the potential between the electrodes should be nearly flat at typical tunnel gaps, we have addressed the difficulty in the computation of the tunneling matrix elements by considering a vacuum region of constant potential delimited by two surfaces (each of them close to tip and sample respectively), then propagating tip and sample wave functions by means of the vacuum Green's function, to finally obtain a closed form in terms of convolutions. The current is then computed for every tip‐sample relative position and for every bias voltage in one shot. The electronic structure of tip and sample is calculated at the same footing, within density functional theory, and independently. This allows us to carry out multiple simulations for a given surface with a database of different tips. We have applied this method to the Si(111)‐(7 × 7) and Ge(111)‐c (2 × 8) surfaces. Topographies and spectroscopic data, showing a very good agreement with experiments, are presented. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
FP‐LAPW investigations of Zn1–xBexS, Zn1–xBexSe and Zn1–xBexTe ternary alloys
Authors: Baaziz H. , Charifi Z. , El Haj Hassan F. , Hashemifar S. J. , Akbarzadeh H. 
Published: March 2006

AbstractThe ab initio full potential linearized augmented plane wave (FP‐LAPW) method within density functional theory was applied to study the effect of composition on the structural and electronic properties of Zn1–x Bex S, Zn1–x Bex Se and Zn1–x Bex Te ternary alloys. The effect of composition on lattice parameter, bulk modulus, band gap and effective mass was investigated. Deviations of the lattice constant from Vegard's law and the bulk modulus from linear concentration dependence were observed for all three alloys. It was deduced that increasing the Be composition in the alloys increases the hardness of the materials. In addition, the calculated band structures showed that the band gap undergoes a direct‐to‐indirect transition at a given concentration. Using the approach of Zunger and co‐workers, the microscopic origins of band gap bowing have been explained. The electron (hole) effective masses were also calculated. The band gap and effective mass were found to vary non‐linearly with Be composition. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Real‐time, real‐space implementation of the linear response time‐dependent density‐functional theory
Authors: Yabana K. , Nakatsukasa T. , Iwata J.‐I. , Bertsch G. F. 
Published: March 2006

AbstractWe review our methods to calculate optical response of molecules in the linear response time‐dependent density‐functional theory. Three distinct formalisms which are implemented in the three‐dimensional grid representation are explained in detail. They are the real‐time method solving the time‐dependent Kohn–Sham equation in the time domain, the modified Sternheimer method which calculates the response to an external field of fixed frequency, and the matrix eigenvalue approach. We also illustrate treatments of the scattering boundary condition, needed to accurately describe photoionization processes. Finally, we show how the real‐time formalism for molecules can be used to determine the response of infinite periodic systems. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Special Issue Current Trends in Electronic Structure: Real‐space, Embedding and Linear Scaling Techniques
Authors: Artacho Emilio , Beck Thomas , Hernández Eduardo 
Published: March 2006

AbstractThis Special Issue of physica status solidi (b) is devoted to the topic of first‐principles simulation of solids, liquids and complex matter and presents articles on the progress in linear scaling methods, electronic transport, simulation of STM images, and time‐dependent DFT methods.The cover picture is taken from the paper by Torsti et al. and shows an isosurface of the positron density localized at a Ga vacancy in GaN [1]. The positron state is calculated by the real‐space code Mika/doppler based on the Rayleigh‐quotient multigrid method. The code predicts positron lifetimes and momentum densities of annihilating electron–positron pairs measured in positron annihilation spectroscopy for defects in solids.
Differentiating structural isomers of sialylated glycans by matrix‐assisted laser desorption/ionization time‐of‐flight/time‐of‐flight tandem mass spectrometry
Authors: Mechref Yehia , Kang Pilsoo , Novotny Milos V. 
Published: March 2006

AbstractUsing model acidic glycans, we demonstrate the benefits of permethylation for matrix‐assisted laser desorption/ionization time‐of‐flight/time‐of‐flight (MALDI/TOF‐TOF) tandem mass spectrometry. With both the linear and branched structures, extensive cross‐ring fragmentation product ions were generated, yielding valuable information on sugar linkages. Elimination of the negative charges commonly associated with sialylated structures through permethylation allowed their structural analysis in the positive ion mode. Extensive A‐ and X‐type ions were observed for the linear structures, and slightly weaker signals for the branched sialylated structures. The diagnostic cross‐ring fragments, permitting a distinction between α2‐3 and α2‐6 linkages of the sialic acid residues, were seen in abundance. Importantly, the cross‐ring fragmentation with the branched structures provides adequate information to assign sialic acid residues, with a specific linkage, to a particular antenna. Copyright © 2006 John Wiley & Sons, Ltd.
Quantitative analysis of an oligomeric hindered amine light stabilizer in polypropylene by matrix‐assisted laser desorption/ionization mass spectrometry using a solid sampling technique
Authors: Taguchi Yoshihiko , Ishida Yasuyuki , Matsubara Hideki , Ohtani Hajime 
Published: March 2006

AbstractA small amount of an oligomeric hindered amine light stabilizer (HALS) (Adekastab LA‐68LD) in polypropylene (PP) materials was directly determined by solid sampling matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) using an internal standard method. First the matrix reagent (dithranol), 20 mg, and the empirically selected internal standard, angiotensin I (MW = 1296.5), 5 µg, were premixed in the solid state. The matrix mixture was then co‐ground with the PP sample containing the HALS in liquid nitrogen using a freezer mill. The powdered sample mixture was spotted on the sample plate, suspended in ion‐exchanged water, dried to adhere on the plate, and subjected to MALDI‐MS. Three series of the HALS components accompanied by the oxidized species were clearly observed as their molecular ions (M.+) along with that of the internal standard in the mass spectra. A fairly good linear relationship (R2 = 0.9991) with a relative standard deviation of ca. 11% was observed between the relative peak intensities of the HALS components and the HALS contents ranging from 0.1–2.5 wt%, which could be used as the calibration line to determine the HALS content in PP composites directly by MALDI‐MS. The UV‐exposed PP composite samples were evaluated by this method to interpret the photostabilizing action of HALS in the PP materials based on the observed change in the relative abundances of the original and oxidized HALS components as a function of UV‐exposure time. Copyright © 2006 John Wiley & Sons, Ltd.
Analysis of strychnos alkaloids using electrospray ionization Fourier transform ion cyclotron resonance multi‐stage tandem mass spectrometry
Authors: Yan Jing , Liu Zhiqiang , Yan Cunyu , Xing Junpeng , Liu Shuying 
Published: March 2006

AbstractThe fragmentations of four strychnos alkaloids have been investigated by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI‐FTICR‐MS) in the positive ion mode. Experiments using multi‐stage tandem mass spectrometry (ESI‐FT‐ICR‐MSn) allowed us to obtain precise elemental compositions of product ions at high mass resolution. The experimental data demonstrated that the nitrogen bridge and the coordinated oxygen atom on the nitrogen bridge in the alkaloid compounds were the active sites in the MS2 fragmentations. The loss of CH3 or the OCH3 group in those alkaloids, which have an OCH3 substituent, was the dominant fragmentation mode in the MS3 fragmentations. Logical fragmentation schemes for strychnos alkaloids have been proposed and these should be useful for the identification of these compounds. Copyright © 2006 John Wiley & Sons, Ltd.
Using interpolation to improve path planning: The Field D* algorithm
Authors: Ferguson Dave , Stentz Anthony 
Published: March 2006

AbstractWe present an interpolation‐based planning and replanning algorithm for generating low‐cost paths through uniform and nonuniform resolution grids. Most grid‐based path planners use discrete state transitions that artificially constrain an agent's motion to a small set of possible headings (e.g., 0,
π/4, π/2, etc.). As a result, even “optimal” grid‐based planners produce unnatural, suboptimal paths. Our approach uses linear interpolation during planning to calculate accurate path cost estimates for arbitrary positions within each grid cell and produce paths with a range of continuous headings. Consequently, it is particularly well suited to planning low‐cost trajectories for mobile robots. In this paper, we introduce a version of the algorithm for uniform resolution grids and a version for nonuniform resolution grids. Together, these approaches address two of the most significant shortcomings of grid‐based path planning: the quality of the paths produced and the memory and computational requirements of planning over grids. We demonstrate our approaches on a number of example planning problems, compare them to related algorithms, and present several implementations on real robotic systems.
Terrain characterization and classification with a mobile robot
Authors: Ojeda Lauro , Borenstein Johann , Witus Gary , Karlsen Robert 
Published: March 2006

AbstractThis paper introduces novel methods for terrain classification and characterization with a mobile robot. In the context of this paper,terrain classificationaims at associating terrains with one of a few predefined, commonly known categories, such as gravel, sand, or asphalt.Terrain characterization, on the other hand, aims at determining key parameters of the terrain that affect its ability to support vehicular traffic. Such properties are collectively called “trafficability.” The proposed terrain classification and characterization system comprises a skid‐steer mobile robot, as well as some common and some uncommon but optional onboard sensors. Using these components, our system can characterize and classify terrain in real time and during the robot's actual mission. The paper presents experimental results for both the terrain classification and characterization methods. The methods proposed in this paper can likely also be implemented on tracked robots, although we did not test this option in our work.
Autonomous straightening and traversing of shipboard helicopters
Authors: Feldman A. R. , Langlois R. G. 
Published: March 2006

AbstractThis paper describes an investigation into autonomous shipboard helicopter maneuvering and traversing operations using the Aircraft/Ship Integrated Secure and Traverse (ASIST) recovery and handling system developed by Indal Technologies, Inc. The ASIST system continuously monitors the aircraft's position and orientation and provides a means of actuation to maneuver the helicopter on deck. This allows the possibility for completely autonomous aircraft securing, maneuvering, and traversing capability. An autonomous maneuvering algorithm offers the potential for automatically selecting the optimal maneuvering sequence and executing it with greater efficiency and reliability than can be achieved by a human operator. The proposed method takes advantage of the position and orientation of the helicopter measured by the existing Helicopter Position Sensing Equipment thereby not requiring additional sensors on the actual helicopter. The paper presents the development and validation of the autonomous straightening and traversing algorithms using a nonlinear on‐deck helicopter maneuvering simulation and the Carleton Experimental Shipboard Helicopter Interface Platform.
Nifedipine therapy for preterm labor: effects on placental, fetal cerebral and atrioventricular Doppler parameters in the first 48 hours
Authors: Guclu S. , Gol M. , Saygili U. , Demir N. , Sezer O. , Baschat A. A. 
Published: March 2006

AbstractObjectiveTo assess the effect of nifedipine tocolysis on Doppler parameters of the uterine, umbilical and fetal middle cerebral arteries and atrioventricular valves in the first 48 h of therapy.MethodsDoppler waveforms of uterine, umbilical and middle cerebral arteries and both atrioventricular valves were measured from 28 pregnant women and fetuses prior to and during nifedipine therapy for preterm labor. Maternal and fetal heart rates (FHR), maternal systolic and diastolic blood pressure, and the Doppler pulsatility index (PI) of the uterine, umbilical and middle cerebral arteries were measured. The cerebroplacental ratio (middle cerebral artery PI/umbilical artery PI) was calculated. The total time velocity integrals (TVIs) of tricuspid and mitral valves and their E‐ and A‐wave peak velocity ratio (E/A) were measured. Friedman repeated‐measures analysis of variance was used to compare the variables before and after nifedipine therapy. If significant differences were found, Wilcoxon's signed ranks test was used to analyze the difference between the two variables. A P‐value of < 0.05 was considered significant.ResultsNifedipine maintenance was associated with a significant decline in maternal systolic and diastolic blood pressure after 24 h, while maternal heart rate and FHR were unaffected. The uterine artery PI had decreased significantly at 24 and 48 h, while the umbilical artery PI did not change significantly. The middle cerebral artery PI had decreased significantly at 24 and again at 48 h. A significant fall in the cerebroplacental Doppler ratio was maintained beyond 24 h. The mean E/A values, TVIs and TVI × FHR values at 24 and 48 h were unchanged from the baseline values.ConclusionsNifedipine maintenance tocolysis is associated with a significant decline in uterine artery and middle cerebral artery Doppler indices 24 h after the first dose. Fetal cardiac diastolic function is unaffected and the significant redistribution observed after 24 h is likely to be attributable to altered cerebral blood flow. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Predicting operative delivery
Authors: Dietz H. P. , Lanzarone V. , Simpson J. M. 
Published: March 2006

AbstractObjectiveUnplanned operative delivery (vaginal or abdominal) is associated with maternal anxiety, maternal and neonatal morbidity and increased resource use. We aimed to identify potential predictors for emergency operative delivery.MethodsThis was a prospective observational study of 202 nulliparous women in a tertiary antenatal unit between 36 and 40 weeks' gestation. The assessment included an interview, a vaginal examination for Bishop score (optional), and a translabial ultrasound examination performed with the woman in a supine position and after voiding to determine cervical length, bladder position on Valsalva, and fetal head engagement. Clinical data were obtained from the institutional obstetric database and patient records.ResultsIn the late third trimester, body mass index (P = 0.016), maternal age at due date (P < 0.0001), history of Cesarean section in first‐degree relatives (P = 0.009), Bishop score (P = 0.0004), cervical length (P = 0.001), bladder position on Valsalva (P = 0.003) and head engagement (P < 0.0001) were significantly associated with delivery mode. On multivariate logistic regression analysis, the best model for predicting normal vaginal delivery contained maternal age, history of Cesarean section, Bishop score and bladder position on Valsalva and had excellent ability to discriminate between normal vaginal delivery and operative delivery (c = 0.85). The model with the best ability to discriminate between vaginal delivery and Cesarean section contained the same parameters plus body mass index; this model performed even better (c = 0.87).ConclusionsIdentification of women at increased risk of operative delivery appears feasible. A combination of clinical and ultrasound variables yielded a model that is likely to predict delivery mode accurately in up to 87% of cases. Such a model may become useful as an entry criterion for intervention trials in women at low or very high risk of operative delivery. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.