bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of 2‐hydroxypropyl‐β‐cyclodextrin and cholesterol on porcine sperm viability and capacitation status following cold shock or incubation
Authors: Galantino‐Homer Hannah L. , Zeng Wen‐xian , Megee Susan O. , Dallmeyer Modesty , Voelkl Dawna , Dobrinski Ina
Published: January 2006

Porcine sperm are extremely sensitive to the damaging effects of cold shock. It has been shown that cholesterol‐binding molecules, such as 2‐hydroxypropyl‐β‐cyclodextrin (HBCD), improve post‐cooling porcine sperm viability when added to an egg yolk‐based extender, but also enhance sperm capacitation in other species. The objective of this study was to determine the effects of HBCD and cholesterol 3‐sulfate (ChS) on porcine sperm viability and capacitation following cold shock or incubation under conditions that support capacitation using a defined medium. We report here that porcine sperm incubated in medium containing both HBCD and ChS have significantly improved viability following cold shock (10 min at 10°C) when compared to sperm incubated without HBCD or ChS, or with either component alone. Treatment with HBCD plus ChS also completely inhibited the increase in protein tyrosine phosphorylation induced by the cold shock treatment or by incubation for 3 hr under conditions that support capacitation. Two assays of sperm capacitation, the rate of calcium ionophore‐induced acrosome reactions and chlortetracycline (CTC) staining, were not significantly altered by HBCD and ChS following cold shock. However, 3‐hr incubation with HBCD plus ChS or with 1 mM ChS alone decreased the percentage of sperm undergoing the induced acrosome reaction without significantly affecting viability when compared to the control. These results indicate that the manipulation of sperm plasma membrane cholesterol content affects porcine sperm viability and capacitation status and could therefore be useful to protect sperm from cold shock during cryopreservation by improving viability without promoting premature capacitation. Mol. Reprod. Dev. © 2006 Wiley‐Liss, Inc.
Relaxometry model of strong dipolar perturbers for balanced‐SSFP: Application to quantification of SPIO loaded cells
Authors: Lebel R. Marc , Menon Ravi S. , Bowen Chris V.
Published: January 2006

Magnetic resonance microscopy using magnetically labeled cells is an emerging discipline offering the potential for non‐destructive studies targeting numerous cellular events in medical research. The present work develops a technique to quantify superparamagnetic iron‐oxide (SPIO) loaded cells using fully balanced steady state free precession (b‐SSFP) imaging. An analytic model based on phase cancellation was derived for a single particle and extended to predict mono‐exponential decay versus echo time in the presence of multiple randomly distributed particles. Numerical models verified phase incoherence as the dominant contrast mechanism and evaluated the model using a full range of tissue decay rates, repetition times, and flip angles. Numerical simulations indicated a relaxation rate enhancement (ΔR2b=0.412γ · LMD) proportional to LMD, the local magnetic dose (the additional sample magnetization due to the SPIO particles), a quantity related to the concentration of contrast agent. A phantom model of SPIO loaded cells showed excellent agreement with simulations, demonstrated comparable sensitivity to gradient echo ΔR*2 enhancements, and 14 times the sensitivity of spin echo ΔR2 measurements. We believe this model can be used to facilitate the generation of quantitative maps of targeted cell populations. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Numerical equilibration of signal intensity and spatial resolution in time‐resolved continuously moving table imaging
Authors: Madhuranthakam Ananth J. , Hu Houchun H. , Kruger David G. , Riederer Stephen J.
Published: January 2006

Time‐resolved continuously moving table imaging techniques have been previously developed to observe a dynamically changing phenomenon over an extended field‐of‐view. The acquisition involves differential k‐space sampling and view sharing. Since the table is continuously moving during data acquisition, the k‐space for any longitudinal position is sampled only sparsely for the first reconstruction timeframe and is progressively more fully sampled for subsequent frames. Consequently, the signal intensity increases and the lateral spatial resolution improves from frame to frame even for static materials, which can mask true dynamically changing phenomena. This work provides a description of this effect and a means for signal correction in the early reconstruction frames, thus permitting any residual variation in signal intensity to be primarily attributed to true dynamic processes. The method is tested experimentally on a static phantom and in a peripheral vascular study designed to observe the leading edge of the contrast bolus. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Fast and reliable analysis of free‐edge stress fields in a thermally loaded composite strip by a layerwise laminate theory
Authors: Mittelstedt Christian , Becker Wilfried
Published: January 2006

A layerwise theory for the analysis of free‐edge effects in thermally loaded symmetric laminates with arbitrary layups is developed. The laminate under investigation is decomposed into an arbitrary number of mathematical layers through the thickness. The theory approach employs displacement terms according to Classical Laminate Plate Theory which are upgraded by layerwise displacement functions. The additional layerwise displacement functions consist of unknown inplane functions and linear thickness terms. The principle of minimum potential energy yields the governing Euler–Lagrange equations which allow for a closed‐form analytical solution for the inplane functions, thus characterizing this method as a semi‐analytical one. The underlying boundary conditions of traction free edges are fulfilled in an integral sense. The present results are in excellent agreement with accompanying finite element computations. Copyright © 2006 John Wiley & Sons, Ltd.
Fourier methods for quasi‐periodic oscillations
Authors: Schilder Frank , Vogt Werner , Schreiber Stephan , Osinga Hinke M.
Published: January 2006

Quasi‐periodic oscillations and invariant tori play an important role in the study of forced or coupled oscillators. This paper presents two new numerical methods for the investigation of quasi‐periodic oscillations. Both algorithms can be regarded as generalizations of the averaging and the harmonic (spectral) balance methods. The algorithms are easy to implement and require only minimal a priori knowledge of the system. Most importantly, the methods do not depend on an a priori co‐ordinate transformation. The methods are applied to a number of illustrative examples from non‐linear electrical engineering and the results show that the methods are efficient and reliable. In addition, these examples show that the presented algorithms can also continue through regions of sub‐harmonic (phase‐locked) resonance even though they are designed only for the quasi‐periodic case. Copyright © 2006 John Wiley & Sons, Ltd.
A quadrature formula for integrals with nearby singularities
Authors: Tsamasphyros G. , Theotokoglou E. E.
Published: January 2006

The purpose of this paper is to propose a new quadrature formula for integrals with nearby singularities. In the boundary element method, the integrands of nearby singular boundary integrals vary drastically with the distance between the field and the source point. Especially, field variables and their derivatives at a field point near a boundary cannot be computed accurately. In the present paper a quadrature formula for 𝓁‐isolated singularities near the integration interval, based on Lagrange interpolatory polynomials, is obtained. The error estimation of the proposed formula is also given. Quadrature formulas for regular and singular integrals with conjugate poles are derived. Numerical examples are given and the proposed quadrature rules present the expected polynomial accuracy. Copyright © 2006 John Wiley & Sons, Ltd.
A stabilized nodally integrated tetrahedral
Authors: Puso M. A. , Solberg J.
Published: January 2006

A stabilized, nodally integrated linear tetrahedral is formulated and analysed. It is well known that linear tetrahedral elements perform poorly in problems with plasticity, nearly incompressible materials, and acute bending. For a variety of reasons, low‐order tetrahedral elements are preferable to quadratic tetrahedral elements; particularly for nonlinear problems. But the severe locking problems of tetrahedrals have forced analysts to employ hexahedral formulations for most nonlinear problems. On the other hand, automatic mesh generation is often not feasible for building many 3D hexahedral meshes. A stabilized, nodally integrated linear tetrahedral is developed and shown to perform very well in problems with plasticity, nearly incompressible materials and acute bending. The formulation is analytically and numerically shown to be stable and optimally convergent for the compressible case provided sufficient smoothness of the exact solution u ∈ C2 ∩ (H1)3. Future work may extend the formulation to the incompressible regime and relax the regularity requirements; nonetheless, the results demonstrate that the method is not susceptible to locking and performs quite well in several standard linear and nonlinear benchmarks. Published in 2006 by John Wiley & Sons, Ltd.
Recent developments in the use of two‐photon polymerization in precise 2D and 3D microfabrications
Authors: Lee Kwang‐Sup , Yang Dong‐Yol , Park Sang Hu , Kim Ran Hee
Published: January 2006

The use of two‐photon polymerization (TPP) initiated by a photosensitizer's non‐linear two‐photon absorption in two‐ and three‐dimensional (2D and 3D) microfabrications for various photonic applications has been intensively studied. Since TPP emerged as a new technology over a decade ago, a large variety of micro‐objects including 3D micro‐optical components, micromechanical devices, and 3D photonic crystals have been fabricated using TPP with a high spatial resolution of approximately submicron scale to 100 nm. Recent efforts have been made to improve the fabrication efficiency and precision of micro‐objects obtained with TPP; in particular, many studies have been carried out with the aim of developing efficient two‐photon absorbing chromophores. In this article, efforts to develop highly efficient two‐photon absorbing materials and also describe recent attempts to enhance the resolution and improve the fabrication efficiency of nanofabrications based on two‐photon polymerization are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Fetomaternal hemorrhage in relation to chorionic villus sampling revisited
Authors: Pelikan Denise M. , Kanhai Humphrey H. , De Groot‐Swings Godelieve M. , Mesker Wilma E. , Tanke Hans J. , Scherjon Sicco A.
Published: January 2006

Objective

To investigate whether chorionic villus sampling (CVS) results in a proportional increase of alpha‐fetoprotein (AFP) and fetal red cells in maternal blood.

Methods

Blood samples were collected before and after CVS. The AFP concentration was measured and supervised automated microscopy of Kleihauer–Betke slides was applied to quantify fetal red cells.

Results

AFP analysis was performed in 53 paired samples and automated microscopic scanning in 59 paired samples. Median AFP concentrations before and after CVS were 12.0 µg/L (range 6.4–36.4) and 18.7 µg/L (range 8.2–668.9), respectively, indicating a significant increase (p < 0.0001). Median numbers of fetal red cells detected before and after CVS were 0 (range 0–36) and 0 (range 0–31), respectively. No significant increase of fetal cells was observed (p = 0.72). The delta (Δ) fetal red cells and the Δ AFP correlated poorly (ρ = −0.22, p = 0.11). The amount of villi correlated moderately with the Δ AFP (ρ = 0.32, p = 0.02) and did not correlate with the Δ fetal red cells (ρ = −0.11, p = 0.43).

Conclusions

Although the AFP concentration after CVS increased, no increase of fetal red cells was detected. These findings suggest that CVS results in a leakage of proteins due to placental tissue damage, rather than increased trafficking of fetal cells. Copyright © 2006 John Wiley & Sons, Ltd.
Prenatal findings in four consecutive pregnancies with fetal Pierson syndrome, a newly defined congenital nephrosis syndrome
Authors: Mark Karlheinz , Reis André , Zenker Martin
Published: January 2006

Objective

To describe the prenatal findings in Pierson syndrome, a newly defined autosomal recessive entity, comprising congenital nephrotic syndrome (CNS) with diffuse mesangial sclerosis and distinct eye abnormalities due to LAMB2 mutations.

Methods

Serial prenatal ultrasound examinations were performed in four consecutive pregnancies affected by Pierson syndrome in the same family. LAMB2 mutations were demonstrated in retrospect by direct sequencing of the gene in the newborn index patient and three abortuses.

Results

Fetal ultrasound consistently revealed marked renal hyperechogenicity associated with variable degree of pyelectasis. These features were detectable by 15 weeks of gestation in all fetuses. Hydrops fetalis due to severe hypalbuminemia demonstrated by chordocentesis occurred in one fetus. Placentas were significantly enlarged. Development of oligohydramnios indicated prenatal decline of renal excretory function. Anencephaly was detected in another fetus with molecularly proven Pierson syndrome at 12 weeks of gestation.

Conclusion

We conclude that Pierson syndrome has to be considered in the differential diagnosis of nephrotic disorders with prenatal onset. Ultrasound criteria for differentiation from the most common type of CNS–congenital nephrosis of the Finnish type (CNF)–are discussed. Because of its prognostic relevance, we advocate molecular genetic testing of LAMB2 in any case of prenatally detected nephrotic syndrome with negative results of NPHS1 mutational screening, especially in the presence of the typical sonomorphologic findings of the kidneys and the development of oligohydramnios. Copyright © 2006 John Wiley & Sons, Ltd.
Intermittent administration of morphine alters protein expression in rat nucleus accumbens
Authors: Li Ka Wan , Jimenez Connie R. , van der Schors Roel C. , Hornshaw Martin P. , Schoffelmeer Anton N. M. , Smit August B.
Published: January 2006

Repeated exposure to drugs of abuse causes time‐dependent neuroadaptive changes in the mesocorticolimbic system of the brain that are considered to underlie the expression of major behavioral characteristics of drug addiction. We used a 2‐D gel‐based proteomics approach to examine morphine‐induced temporal changes in protein expression and/or PTM in the nucleus accumbens (NAc) of morphine‐sensitized rats. Rats were pretreated with saline [1 mL/kg subcutaneously (s.c.)] or morphine (10 mg/kg, s.c.) once daily for 14 days and the animals were decapitated 1 day later. The NAc was extracted and proteins resolved by 2‐DE. Several protein functional groups were found to be regulated in the morphine‐treated group, representing cytoskeletal proteins, proteins involved in neurotransmission, enzymes involved in energy metabolism and protein degradation, and a protein that regulates translation.
Down‐regulation of the strawberry Bet v 1‐homologous allergen in concert with the flavonoid biosynthesis pathway in colorless strawberry mutant
Authors: Hjernø Karin , Alm Rikard , Canbäck Björn , Matthiesen Rune , Trajkovski Karin , Björk Lars , Roepstorff Peter , Emanuelsson Cecilia
Published: January 2006

Proteomic screening of strawberry (Fragaria ananassa) yielded a 58% success rate in protein identification in spite of the fact that no genomic sequence is available for this species. This was achieved by a combination of MALDI‐MS/MS de novo sequencing of double‐derivatized peptides and indel‐tolerant searching against local protein databases built on both EST and full‐length nucleotide sequences. The amino acid sequence of a strawberry allergen, homologous to the well‐known major birch pollen allergen Bet v 1, was partially determined. This strawberry allergen, named Fra a 1 according to the nomenclature for allergen proteins, showed sequence identity of 54 and 77%, respectively, with corresponding allergens from birch and apple. Differential expression, as evaluated by 2‐D DIGE, occurred in 10% of protein spots when red strawberries were compared to a colorless (white) strawberry mutant. White strawberries, known to be tolerated by individuals affected by allergy, were found to be virtually free from the strawberry allergen. Also several enzymes in the pathway for biosynthesis of flavonoids, to which the red color pelargonidin belongs, were down‐regulated. This approach to assess differential protein expression without access to genomic sequence information can also be applied to other crop plants and phenotypic traits.
Prediction of experimentally unknownredistances of organic molecules from Dunning basis set extrapolations forab initiopost‐HF calculations
Authors: Neugebauer Alexander , Häfelinger Günter
Published: January 2006

An approach to estimate equilibriumrebond lengths of organic molecules which contain standard bonding situations for CC, CH, CO and CN distances from only one equation is presented. For this, optimizations of molecular geometries using correlated post‐Hartree–Fock and density functional methods have been performed. A selection scheme was developed to determine the most reliable methodology for prediction of equilibriumredistances of covalent bonds from a set of investigated theoretical methods. Consequently, distances computed in the CCSD(T) procedure via exponential extrapolation from a consecutive set of Dunning cc‐pVXZ basis sets by use of Eqn (2) are accurate up to ± 0.0005 Å in comparison to experimentally availableredistances. Applications for predictions of the experimentally unknownredistances of methanol, methylamine and methylenimine are presented.

Additionally the estimation ofredistances of larger, chemically more interesting molecules is possible by lower order calculations (e.g. DFT B3LYP/cc‐pVDZ) via linear correlation statistics using the results from ourrereference model system via Eqn (3). Copyright © 2006 John Wiley & Sons, Ltd.
Cocuring behaviors of benzoxazine and maleimide derivatives and the thermal properties of the cured products
Authors: Liu Ying‐Ling , Yu Juin‐Meng
Published: January 2006

The cocuring behaviors of 3‐phenyl‐3,4‐dihydro‐2H‐1,3‐benzoxazine (P‐ABz) and various N‐phenylmaleimide compounds were studied with DSC, FTIR, and TGA‐GC/MS. The presence of benzoxazine compound promoted the polymerization of maleimide groups. In contrast, 4‐hydroxyphenylmaleimide (MI‐OH) and 4‐maleimidobenzoic acid (MI‐COOH), which possess acidic moieties, showed an acid‐catalytic effect on the polymerization of benzoxazine groups. The cocuring composition of P‐ABz/MI‐COOH showed low polymerization temperatures, high glass transition temperature above 220 °C, and comparable thermal stability to conventional polybenzoxazines. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1890–1899, 2006
Atom transfer graft copolymerization of 2‐ethyl hexylacrylate from labile chlorines of poly(vinyl chloride) in an aqueous suspension
Authors: Bicak Niyazi , Karagoz Bunyamin , Emre Dilek
Published: January 2006

Copper‐mediated atom transfer radical polymerization (ATRP) is presented as a versatile tool for the graft copolymerization of 2‐ethyl hexylacrylate with poly(vinyl chloride) (PVC) in an aqueous suspension. The appreciable solubility of PVC in 2‐ethyl hexylacrylate (30%) at temperatures around 130 °C makes grafting of the monomer possible from labile chlorines of PVC in aqueous suspensions without the use of additional solvent. The first‐order kinetics (rate constant k = 4.2 × 10−6 s−1) of the mass percentage increase reveals a typical ATRP fashion of the graft copolymerization at low conversions. The use of a completely organosoluble copper(I) complex of hexylated triethylene tetramine, in combination with α‐methylcellulose as a stabilizer, makes the graft copolymerization possible in a dispersed organic phase. Nearly spherical, green particles can be obtained with moderate stirring rates (1000 rpm) in high graft yields. Although the kinetics of the reaction deviates from the first order at high conversions, reasonable graft yields (146%) can be attained within a reaction period of 24 h. In this study, the reaction conditions of the grafting have been studied, and graft products have been confirmed by common techniques such as 1H NMR, gel permeation chromatography, and differential scanning calorimetry. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1900–1907, 2006
Phase separation, porous structure, and cure kinetics in aliphatic epoxy resin containing hyperbranched polyester
Authors: Guo Qipeng , Habrard Alexia , Park Yoosup , Halley Peter J. , Simon George P.
Published: January 2006

Thermosetting blends of an aliphatic epoxy resin and a hydroxyl‐functionalized hyperbranched polymer (HBP), aliphatic hyperbranched polyester Boltorn H40, were prepared using 4,4′‐diaminodiphenylmethane (DDM) as the curing agent. The phase behavior and morphology of the DDM‐cured epoxy/HBP blends with HBP content up to 40 wt % were investigated by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM). The cured epoxy/HBP blends are immiscible and exhibit two separate glass transitions, as revealed by DMA. The SEM observation showed that there exist two phases in the cured blends, which is an epoxy‐rich phase and an HBP‐rich phase, which is responsible for the two separate glass transitions. The phase morphology was observed to be dependent on the blend composition. For the blends with HBP content up to 10 wt %, discrete HBP domains are dispersed in the continuous cured epoxy matrix, whereas the cured blend with 40 wt % HBP exhibits a combined morphology of connected globules and bicontinuous phase structure. Porous epoxy thermosets with continuous open structures on the order of 100–300 nm were formed after the HBP‐rich phase was extracted with solvent from the cured blend with 40 wt % HBP. The DSC study showed that the curing rate is not obviously affected in the epoxy/HBP blends with HBP content up to 40 wt %. The activation energy values obtained are not remarkably changed in the blends; the addition of HBP to epoxy resin thus does not change the mechanism of cure reaction of epoxy resin with DDM. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 889–899, 2006
Pressure‐induced metallization and structural evolution of Cu3N
Authors: Zhao J. G. , Yang L. X. , Yu Y. , You S. J. , Liu J. , Jin C. Q.
Published: January 2006

In situ resistance evolution with pressure of anti‐perovskite nitride Cu3N was measured using the diamond anvil cell (DAC) technique up to 20.0 GPa at room temperature. A sharp drop of resistance from 105 Ω at ambient pressure to several Ω was observed in the range 3.0–10.0 GPa. This is an indication of the pressure‐induced metallization in the Cu3N semiconductor. Meanwhile we also performed the high‐pressure energy dispersive X‐ray diffraction experiments on Cu3N at the pressures up to 39.2 GPa. It was found that a crystal structure phase transition begins to take place at ∼5.0 GPa on Cu3N, which is generally consistent with the electronic conductance results. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Efficient coupling into confined optical modes of ZnSe‐based pillar microcavities
Authors: Lohmeyer H. , Sebald K. , Gutowski J. , Kruse C. , Hommel D. , Wiersig J. , Baer N. , Jahnke F.
Published: January 2006

Monolithic II–VI pillar microcavities made of ZnCdSSe/ZnSSe λ cavities and Bragg mirrors composed of ZnSSe and MgS/ZnCdSe supperlattices have been fabricated by molecular‐beam epitaxy and focused‐ion‐beam etching. Discrete optical modes of the pillar microcavities are studied in photoluminescence measurements. The measured data show full agreement with calculations based on an extended transfer‐matrix method. A strong enhancement in the detected photoluminescence signal is obtained for single emitters in resonance with modes of the cavity. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magneto‐optical properties in hybrid nanostructures of II–VI diluted magnetic semiconductors with perpendicular ferromagnetic films
Authors: Sakuma M. , Hyomi K. , Souma I. , Murayama A. , Oka Y.
Published: January 2006

Hybrid nanostructures of a diluted magnetic semiconductor quantum well (DMS‐QW) of Zn1–x –y Cdx Mny Se have been fabricated with a ferromagnetic Co/Pt‐multilayered film, by electron beam lithography. The disk structure of the DMS‐QW with the diameter of 100 nm was embedded in the magnetic thin film with the thickness of 50 nm. Giant Zeeman effects of excitons in the DMS‐QW in the hybrid structure are studied by micro‐photoluminescence (PL) spectroscopy. The Co/Pt film shows perpendicular magnetization without external field, and therefore it can generate magnetic fields nearly perpendicular to the DMS‐QW plane in the hybrid structure. As the result, the circularly polarized excitonic PL arises in zero external field, indicating that the perpendicular magnetic field applied from the Co/Pt film aligns the exciton spins in the DMS‐disk in the present hybrid structure. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inter‐dot spin exchange interaction in coupled II–VI semiconductor quantum dots
Authors: Lee S. , Dobrowolska M. , Furdyna J. K.
Published: January 2006

We have performed polarization selective photoluminescence (PL) experiment on a series of self‐assembled quantum dots (QDs) in the form of single‐ and double‐QD layer systems. The double layers were formed from diluted magnetic semiconductor (DMS) (either CdMnSe or CdZnMnSe) and non‐DMS (either CdSe or CdZnSe) layers, separated by non‐DMS ZnSe barriers. The peaks from DMS and non‐DMS QD layers are clearly resolved in the PL spectra taken at zero magnetic field. When a magnetic field is applied to the double layer QD (DLQD) system, the intensities of the circularly polarized PL peaks corresponding to the non‐DMS (i.e., CdSe and CdZnSe) layers exhibit significant changes, reflecting correspondingly large changes in the degrees of spin polarization of the non‐DMS QDs. This enhancement of spin polarization observed in the double‐layer QD structures is interpreted in terms of anti‐parallel spin interaction between carriers localized in the coupled QD pairs. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Coherent control of excitonic excitations in II–VI quantum wells
Authors: Voss Tobias , Breunig Hans Georg , Rückmann Ilja , Gutowski Jürgen
Published: January 2006

We present results of experimental work in which the coherent‐control technique has been applied to study the coherent manipulation of excitonic polarization in ZnSe quantum‐well samples. We will introduce the linear control of excitonic polarization in pulse‐transmission experiments and afterwards focus on the question if and how the optical transition from the excitonic states to the bound‐biexciton state can be subject to a directed coherent control. The experimental results will be compared to simulations based on a microscopic theory and will also be explained on the base of a phenomenological few‐level model. The overall suitability of coherent control for the investigation of exciton systems in low‐dimensional wide‐gap materials will be discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stimulated emission from ZnO nanorods
Authors: Hauschild R. , Lange H. , Priller H. , Klingshirn C. , Kling R. , Waag A. , Fan H. J. , Zacharias M. , Kalt H.
Published: January 2006

By means of time resolved spectroscopy we compare two samples of ZnO nanorods with respect to their suitability as stimulated emitters. In the case of narrow nanorods their wave guiding quality causes a suppression of exciton–exciton scattering whereas no laser emission is detectable. Unlike their narrow counterparts, wide nanorods not only benefit from a larger overlap of the guided mode with the gain medium but a variation in VLS growth results in gold nanoparticles being present at the bottom of nanorods. Consequently, laser emission from single wide rods is evidenced up to 150 K. In addition to experimental studies we carry out 3D numerical simulations of the electric field distribution to evaluate the influence of gold nanoparticles at the nanorod/substrate interface. This finite element analysis confirms that gold leads to an enhancement of confinement within the resonator. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of surface treatment on properties of ZnTe LED fabricated by Al thermal diffusion
Authors: Tanaka Tooru , Hayashida Kazuki , Saito Katsuhiko , Nishio Mitsuhiro , Guo Qixin , Ogawa Hiroshi
Published: January 2006

Three kinds of surface treatments of ZnTe have been investigated for the fabrication of the light emitting diode (LED) by Al thermal diffusion. In case that a wet cleaning process was used, a poly‐crystalline layer remains on the surface of ZnTe whereas a clean surface was obtained by using in situ thermal or H radical cleaning processes. However, a series resistance of the LED fabricated on a clean surface is much higher than those fabricated using the wet cleaning process, indicating that a clean interface leads to a formation of a heavily Al doped layer with high compensation by the Al diffusion. Based on these results, we have attempted to control an interface by inserting an oxide layer intentionally on a clean surface of ZnTe. As a consequence, we have found that an Al concentration in the diffused layer can be controlled by changing the thickness of the oxidation layer, resulting in obtaining a LED with better performance. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐temperature defect study of tellurium‐enriched CdTe:In
Authors: Grill R. , Fochuk P. , Franc J. , Nahlovskyy B. , Höschl P. , Moravec P. , Zakharuk Z. , Nykonyuk Ye. , Panchuk O.
Published: January 2006

The defect structure of donor‐doped Te‐rich CdTe is studied theoretically within quasi‐chemical formalism and experimentally in heavily In‐doped CdTe by in situ high temperature galvanomagnetic measurements in the temperature interval 900–200 °C. The experimental data are evaluated within defect model optimized to recent high temperature experiments and assuming doping‐induced band gap renormalization. We show that a proper thermal treatment can be conveniently used for the optimization of room temperature electric properties and for a preparation of the semi‐insulating detector grade material with a deep level doping below the limit 1013 cm–3 demanded in the detector industry. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Exciton self‐trapping in MEH‐PPV films studied by ultrafast emission depolarization
Authors: Ruseckas Arvydas , Samuel Ifor D. W.
Published: January 2006

Depolarization of the transient absorption with a time constant of <120 fs is observed in poly[2‐(2′‐ethylhexyloxy)‐5‐methoxy‐1,4‐phenylenevinylene] (MEH‐PPV) film. It is too fast to be explained by incoherent hopping. We attribute it to dynamic localization (self‐trapping) of the initially delocalized excitons driven by structural relaxation of excited segments. Implications for charge carrier photogeneration are briefly discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Charge‐carrier mobilities in disordered semiconducting polymers: effects of carrier density and electric field
Authors: Meisel K.D. , Pasveer W.F. , Cottaar J. , Tanase C. , Coehoorn R. , Bobbert P.A. , Blom P.W.M. , de Leeuw D.M. , Michels M.A.J.
Published: January 2006

We model charge transport in disordered semiconducting polymers by hopping of charge carriers on a square lattice of sites with Gaussian on‐site energy disorder, using Fermi‐Dirac statistics. From numerically exact solutions of the Master equation, we study the dependence of the charge‐carrier mobility on temperature, carrier density, and electric field. Our results are used in calculating current‐voltage characteristics of hole‐only polymer diodes. It is found that very good fits to experimental current‐voltage characteristics can be obtained at different temperatures, with reasonable fitting parameters for the width of the Gaussian density of states and the lattice constant. In agreement with the experiments we find that the density dependence is dominant over the field dependence. Only at high fields and low temperatures the field dependence becomes noticeable. The potential and current distribution show strong inhomogeneities, which may have important consequences for the operation of polymer opto‐electronic devices. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of interactions and disorder on the compressibility of two‐dimensional electron and hole systems
Authors: Savchenko A. K. , Galaktionov E. A. , Allison G. D. , Fogler M. M. , Safonov S. S. , Simmons M. Y. , Ritchie D. A.
Published: January 2006

We have studied the thermodynamic compressibility of 2D electron and 2D hole gases near the apparent metal‐insulator transition, in the ranges of the interaction parameter rs =1–2.5 and rs =10–30, respectively. Nonmonotonic dependence of the inverse compressibility on the carrier density is observed with an upturn at low densities. Despite the large difference in rs , this behaviour of inverse compressibility in both electron and hole systems can be quantitatively accounted for by a nonlinear screening of disorder by the carriers, in particular, by the disorder‐driven proliferation of depletion regions in the 2D channel. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The European Conference Physics of Magnetism (PM'05) Poznań, Poland, 24–27 June 2005
Authors: Idzikowski B. , Barnaś J. , Micnas R. , Jezierski A. , Szajek A. , Wojciechowski R. J.
Published: January 2006

Papers presented at The European Conference Physics of Magnetism (PM'05) were published in the January 2006 issues of physica status solidi(b)and(c)[1, 2]. Please find the Preface by the Guest Editors of the Proceedings as well as the listings of Conference Chairs, Committees and Sponsors, which were unintentionally omitted from the journals, reprinted here.
Fast gas chromatography/mass spectrometric assay for the validated quantitative determination of methadone and the primary metabolite EDDP in whole blood
Authors: Gunnar Teemu , Eskola Tanja , Lillsunde Pirjo
Published: January 2006

A toxicological analysis was developed and validated for simultaneous screening and quantification of methadone (METH) and its primary metabolite 2‐ethylidene‐1,5‐dimethyl‐3,3‐diphenylpyrrolidine (EDDP). The method employs microscale liquid‐liquid extraction (µLLE) and direct injection of a separated aliquot of the organic layer into a gas chromatography/mass spectrometric (GC/MS) system without any other pre‐treatment stages. A fast GC/MS runtime (total 5.8 min; METH, Rt = 3.55 min; EDDP, Rt = 3.40 min) combined with rapid sample preparation allowed cost‐efficient and routinely applicable performance with a low amount of manual work. The validated parameters included: linearity (25–1000 ng mL−1 both; R = 0.998 and R = 0.997), accuracy (BiasMETH: from −0.05 to 11.3%, BiasEDDP: from 1.11 to 4.37%); intra and inter‐assay precision (RSDMETH: from 2.4 to 3.9%, from 4.89 to 10.3%; RSDEDDP: from 4.50 to 6.20%, from 4.57 to 15.2%), extraction efficiency (METH = 95.5%; EDDP = 90.6%), LOQMeth,EDDP = 25 ng mL−1. Samples were stable for at least 25 h and no selectivity problems or baseline interference were observed. The method should be applicable for identifying and quantitative confirmation of possible misuse and/or illegal use of METH in toxicological cases. Copyright © 2006 John Wiley & Sons, Ltd.
The use of desorption/ionization on porous silicon mass spectrometry for the detection of negative ions for fatty acids
Authors: Budimir Natali , Blais Jean‐Claude , Fournier Françoise , Tabet Jean‐Claude
Published: January 2006

The study of low molecular weight compounds by matrix‐assisted laser desorption/ionization (MALDI) is difficult because of the presence of ions originating from the matrix in the low‐m/z range. In order to resolve these problems, new matrix‐free approaches were developed based on laser desorption/ionization from the surface of various materials such as graphite and porous silicon. Our work involves the use of ‘desorption ionization on porous silicon mass spectrometry’ (DIOS‐MS) in the negative ion mode to study fatty acid compounds. The potential of the DIOS‐MS technique is shown and an insight into the ionization mechanism provided. Copyright © 2006 John Wiley & Sons, Ltd.
Ultrasound diagnosis of fourth branchial arch sinus at 22 weeks' gestation
Authors: Horowitz E. , Rabinerson D. , Mashiach R. , Shalev J. , Meizner I.
Published: January 2006

Fourth branchial arch sinus is the rarest of the branchial cleft anomalies and its prenatal detection has not previously been reported in the English literature. We describe a case of fourth branchial arch sinus identified in a fetus during a routine ultrasound evaluation at 22 weeks' gestation. Survey of the fetal anatomy revealed a small ‘nipple‐like’ structure on the neck, arising anteriorly to the sternocleidomastoid muscle, midway between the chin and the left shoulder. The structure persisted unchanged throughout the pregnancy. The prenatal diagnosis of fourth branchial arch sinus was confirmed at delivery at term. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Synthesis and Structure of 1,1'‐Bis(pyridinylamino)ferrocenes
Authors: Karakuzu Aykut , Maisel Heidi , Irrgang Torsten , Kempe Rhett
Published: January 2006

Ferrocenyl bridged bisaminopyridines were synthesized from 2‐bromopyridine or 2‐bromo‐4‐methylpyridine and 1,1'‐diaminoferrocene using palladium catalysed aryl amination. X‐ray crystal structure analysis of the two bisaminopyridines revealed the formation of dimers in the solid state. The formation of the dimers occurs via four H‐bonds between the amino N‐H function and the pyridine nitrogen atoms.
Synthesis, Crystal Structures, and Magnetic Properties of Three New Iron Complexes Derived from 3,5‐Bis(pyridin‐2‐yl)‐1,2,4‐triazole
Authors: Chen Jing‐Cai , Hu Sheng , Zhou Ai‐Ju , Tong Ming‐Liang , Tong Ye‐Xiang
Published: January 2006

Two new iron(III) complexes and one iron(II) complex have been synthesized from the solvothermal reactions of FeCl3·6H2O with 3,5‐bis(pyridin‐2‐yl)‐1,2,4‐triazole (Hbpt) in methanol or acetonitrile. KSCN acted as the reducing agent in the synthesis of iron(II) complex of 3. [FeCl3(Hbpt)(H2O)]·H2O (1) crystallizes in the triclinic space group $P{\bar 1}$ with a = 7.475(1), b = 9.468(2), c = 12.309(2) Å, α = 73.880(2), β = 74.746(2), γ = 81.849(2)°, V = 805.2(2) Å3, Z = 2. [Fe2(bpt)2Cl4] (2): orthorhombic space group Pnnm with a = 9.895(2), b = 10.632(2), c = 13.195(2) Å, V = 1388.1(4) Å3, Z = 2. [Fe2(bpt)2(MeOH)2Cl2] (3): orthorhombic space group Pbca with a = 14.4204(16), b = 9.8737(11), c = 19.792(2) Å, V = 2818.1(5) Å3, Z = 4. 1 features the first structurally characterized metal complex of the neutral Hbpt ligand in which the Hbpt ligand adopts an unprecedented zwitterionic form. 2 shows a neutral dinuclear iron(III) complex and the [Fe2(bpt)2]4+ unit is ideally planar. The two iron(III) ions separated by a distance of 4.408(2) Å are doubly triazolate‐bridged. Each dimeric unit is connected with six other dimeric ones via the bifurcated C‐H···Cl hydrogen bonds, these connections extend the dimeric moieties into a three‐dimensional molecular architecture. 3 is a neutral centrosymmetric dinuclear FeII complex, in which intermolecular moderate O‐H···N hydrogen bonding interactions between the methanol molecules and 4‐position nitrogen atoms of the triazolato groups extend the dinuclear species into a two‐dimensional supramolecular architecture of (4,4) topology. Magnetic studies indicate there exists an antiferromagnetic spin coupling in FeIII2 and FeII2 units via the double triazolate bridges in 2 and 3.
Structure of Bromotrinitrosyl Iron, [Fe(NO)3Br], and DFT Calculations of the Structures of [Fe(NO)3X] (X = Cl, Br, I)
Authors: Beck Wolfgang , Klapötke Thomas M. , Mayer Peter
Published: January 2006

Bromotrinitrosyl iron was prepared by passing a stream of nitrogen monoxide over a mixture of iron dibromide and iron powder at elevated temperatures. It readily loses NO to give [(ON)2Fe(μ‐Br)Fe(CO)2]. The structure of freshly obtained [Fe(NO)3Br] was determined by X‐ray diffraction at 200 K and shows (distorted) tetrahedral coordination with N–Fe–N and N–Fe–Br angles of 107.9(2)° and 111.0(2)° and bent Fe–N–O groups (162.5(6)°). The DFT calculations in the series [Fe(NO)3X] (X = Cl, Br, I) reproduce well the experimental structural parameters and vibrational frequencies.
Phosphorus NMR Characterisation of P–N Bond Rotamers of a α‐P4S3 Amide with a Conformationally Constrained Chiral Substituent
Authors: Tattershall Bruce W. , Knight Julian G. , Andrews Mark J. , Booth Claire L.
Published: January 2006

Reactions of bicyclic α‐P4S3I2 with Hpthiq gave solutions containing α‐P4S3(pthiq)I and α‐P4S3(pthiq)2, where Hpthiq is the conformationally constrained chiral secondary amine 1‐phenyl‐1,2,3,4‐tetrahydroisoquinoline. The expected diastereomers have been characterised by complete analysis of their 31P{1H} NMR spectra. Hindered P–N bond rotation in the amide iodide α‐P4S3(pthiq)I caused greater broadening of peaks in the room‐temperature spectrum of one diastereomer than in that of the other. At 183 K, spectra of two P–N bond rotamers for each diastereomer were observed and analysed. The minor rotamers showed strong evidence for steric crowding, having large diastereomeric differences in 1J(P–P) and 2J(P–S–P) couplings (49 Hz, 16 % of value, and 4.4 Hz, 19 % of value, respectively).
Unexpected Formation of a π‐Coordinate Schiff Base Cobalt(0) Complex
Authors: Yu Fengli , Li Xiaoyan , Sun Hongjian
Published: January 2006

Both tetrakis(trimethylphosphine)cobalt(0) and methyltetrakis(trimethylphosphine)cobalt(I) react with 2‐(benzylideneamino)pyridine (1) exclusively giving a complex of composition (η2(N,C)‐2‐Py‐N=CH‐C6H5)Co(PMe3)3 (2), which is shown by single‐crystal X‐ray diffraction to constitute the first π‐coordinate imine cobalt(0) complex. The route of formation is proposed and discussed.
Every mother is a working mother: Breastfeeding and women's work
Authors: O'Gara C. , Canahuati J. , Moore Martin A.
Published: January 2006

Working and breastfeeding can be very complicated because of the kinds of work women are doing; the settings in which they are working; recent changes which have made breastfeeding and work less compatible; trade‐offs that working mothers must make; the importance of breastfeeding for the working woman; and the range of feeding options for working mothers. To adequately address these and other issues, several initiatives are needed: (1) additional research on breast pumping and breastmilk storage, and the social and emotional benefits of breastfeeding for working mothers and their infants; (2) protective legislation and strategies for its implementation and monitoring; (3) information and support for breastfeeding mothers and families, policy makers, and the general public; and (4) an alliance between breastfeeding advocates and feminists to promote this intrinsically female issue.
Breastfeeding and feminism
Authors: Van Esterik P.
Published: January 2006

Breastfeeding empowers women and contributes to gender equality; therefore, it is an important feminist, human rights, and women's issue. Although seldom addressed as a feminist issue, breastfeeding is paradigmatically one because it requires rethinking basic issues such as the sexual division of labor, the fit between women's productive and reproductive lives, and the role of physiological processes in defining gender ideology. The conceptual problems which emerge in the fit between breastfeeding promotion and feminist theory include the place of motherhood; technology versus liberation; fear of biological determinism; breasts and sexuality; locating guilt; personal choice; romanticizing breastfeeding; and conceptualizing women's work. Feminist theorists who take up breastfeeding as an issue and medical researchers who address questions raised by feminist theory have the occasion to produce a non‐dualistic feminist problematic that would draw together a wide range of theories and practices that go beyond breastfeeding and mothering. The failure to develop this analysis could have serious consequences.
Role of the actin cytoskeleton during respiratory burst in chemoattractant‐stimulated neutrophils
Authors: Bengtsson Torbjörn , Orselius Kristina , Wetterö Jonas
Published: January 2006

The aim of this study was to clarify the role of the actin cytoskeleton during chemotactic peptide fMet‐Leu‐Phe (fMLF)‐stimulated respiratory burst in human neutrophil granulocytes. Reactive oxygen species (ROS) was measured as luminol‐amplified chemiluminescence (CL) and F‐actin content as bodipy phallacidin fluorescence in neutrophils treated with latrunculin B or jasplakinolide, an inhibitor and activator of actin polymerization, respectively. Latrunculin B markedly decreased, whereas jasplakinolide increased, the F‐actin content in neutrophils, unstimulated or stimulated with fMLF. Latrunculin B enhanced the fMLF‐triggered ROS‐production more than tenfold. Jasplakinolide initially inhibited the fMLF‐induced CL‐response, however, caused a potent second sustained phase (>400% of control). Both actin drugs triggered a substantial CL‐response when added 5–25 min after fMLF. This was also valid for chemotactic doses of fMLF, where latrunculin B and jasplakinolide amplified the ROS‐production 5–10 times. By using specific signal transduction inhibitors, we found that the NADPH oxidase activation triggered by destabilization of the actin cytoskeleton occurs downstream of phospholipase C and protein kinase C but is mediated by Rho GTPases and tyrosine phosphorylation. In conclusion, rearrangements of the actin cytoskeleton are a prerequisite in connecting ligand/receptor activation, generation of second messengers and assembly of the NADPH oxidase in neutrophil granulocytes.
Ketorolac prevents recurrent withdrawal induced hyperalgesia but does not inhibit tolerance to spinal morphine in the rat
Authors: Dunbar Stuart A. , Karamian Ivan , Zhang Jiahui
Published: January 2006

Chronic use of opioid is associated with pro‐nociceptive phenomena such as hyperalgesia or tolerance. The interaction between opioid and non‐steroidal anti‐inflammatory drugs (NSAIDs) with respect to opioid‐associated hyperalgesia and tolerance remains largely unknown. This study examines the effect of subcutaneous or intrathecal administration of ketorolac, an NSAID, on recurrent withdrawal induced hyperalgesia and tolerance to spinal morphine in rats. Animals were infused with morphine intrathecally, and daily subcutaneous naloxone was used for recurrent withdrawal purpose. We observed that escape latencies on hot box were decreased in animals subjected to withdrawal, and this decrease was reversed by subcutaneous ketorolac pretreatment. In addition, we observed that recurrent withdrawal did not significantly affect the magnitude of spinal morphine tolerance. Compared to controls, all morphine infused animals showed similar changes in their dose responses to spinal morphine, effective dose 50 values and tolerance ratios; and these changes were not affected by the ketorolac given subcutaneously. The effect of ketorolac on tolerance was further examined by directly delivering ketorolac to the spinal cord, and again we observed similar changes in the daily latency, percentage of area under the curve and percentage of maximal possible effects among groups infused with morphine, regardless of intrathecal ketorolac treatment. Together, our results demonstrate that recurrent withdrawal is associated with hyperalgesia but this has no effect on the tolerance development; ketorolac protects against recurrent withdrawal induced hyperalgesia without significantly altering spinal morphine tolerance.