bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of a slowly degrading biodegradable polyesterurethane for tissue engineering scaffolds
Authors: Henry Jerome A. , Simonet Marc , Pandit Abhay , Neuenschwander Peter
Published: February 2007

The purpose of this research was to develop and characterize a novel, slowly degrading polyesterurethane. In this study, a polyesterurethane with a crystalline segment of poly((R)‐3‐hydroxybutyric acid)‐diol linked by a diisocyanate to an amorphous segment of poly(ε‐caprolactone‐co‐glycolide)‐diol was synthesized. Porous and nonporous scaffolds were processed using electrospinning and solvent casting respectively. The morphology, pore size, and filament diameter of the mesh and film were characterized using scanning electron microscopy (SEM). The thermal properties were examined using differential scanning calorimetry (DSC). A degradation study was initiated to characterize the change in mechanical properties, molecular weight, and surface morphology over 12 months using tensile testing, gel permeation chromatography (GPC), and SEM respectively. Concomitantly, cell morphology and viability on these variants were investigated using fibroblasts. The mechanical test data indicated a gradual decrease in the ultimate tensile strength and strain to break while the modulus of elasticity remained stable. GPC data suggested a slow decrease in the molecular weight while SEM examination revealed changed surface morphologies. The in vitro studies implied that the novel poly‐esterurethane was not cytotoxic and that the mesh was a more favorable scaffold towards cell viability. The summation of these results suggests that this polyesterurethane has the potential for tissue engineering applications. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2007
Revegetation of mineral clay soils: shrub and tree species compared
Authors: Muzzi E. , Fabbri T.
Published: February 2007

Several species of shrubs and trees used in the revegetation of clay mineral soils in Northern Appennine region were compared. The trial site, a quarry land, with clay soil with high pH and a little organic matter was arranged in three randomized block designs. The trial tested the following shrub species Rhamnus cathartica, Colutea arborescens, Euonymus europea, Viburnum opulus, Sambucus nigra, Cotinus coggygria, Coronilla emerus, Crataegus monogyna, Ligustrum vulgare, Prunus spinosa, Spartium junceum, Cornus sanguinea, Paliurus spina‐christi and the tree species Fraxinus excelsior, Fraxinus angustifolia, Corylus avellana, Sorbus domestica, Prunus avium, Acer monspessulanum, Ostrya carpinifolia, Pyrus communis var. pyraster, Ulmus minor, Fraxinus ornus and Acer campestre. The present study was designed to test the adaptive response of the species transplanted in clay soil without preparatory tilling or dressing operations. The overall 9 year data indicate differences in the species tested: Spartium junceum, Ligustrum vulgare and Cotinus coggygria were the shrubs adapted to these edaphics conditions and planting practises together with Sorbus domestica, Pyrus pyraster, Fraxinus ornus and Fraxinus angustifolia. Animal damages were also evaluated. Copyright © 2007 John Wiley & Sons, Ltd.
Experience counts: Learning lessons from key events
Authors: Ernst Christopher , Martin André
Published: February 2007

How can leaders help their groups learn lessons—whether positive or negative—from key events? A process that CCL calls critical reflections begins with a key event and is followed by three stages: exploring, reflecting, and projecting. The goal is to create a specific action plan that will set the stage for a productive future.
Spreading the word: How to self‐promote with integrity
Authors: Hernez‐Broome Gina , McLaughlin Cindy , Trovas Stephanie
Published: February 2007

For leaders and the groups they lead, doing a good job is often not enough to gain the visibility and recognition they deserve. What's needed is some self‐promotion, carried out intentionally and strategically. Many leaders have a negative view of self‐promotion, but there are ways for them—and their organizations—to benefit from it while still maintaining integrity and authenticity.
A remark on the decay of solutions to the 3‐D Navier–Stokes equations
Authors: Zhou Yong
Published: February 2007

In this paper we derive a decay rate of the L2‐norm of the solution to the 3‐D Navier–Stokes equations. Although the result which is proved by Fourier splitting method is well known, our method is new, concise and direct. Moreover, it turns out that the new method established here has a wide application on other equations. Copyright © 2007 John Wiley & Sons, Ltd.
Maximal and sustained isokinetic lower‐limb muscle strength in hospitalized older people
Authors: Muller François , Dehail Patrick , Bestaven Emma , Petit Julien , Joseph Pierre‐Alain , Barat Michel , Mazaux Jean‐Michel , Bourdel‐Marchasson Isabelle
Published: February 2007

Maximal strength decreases with aging whereas sustained strength is less affected. Strength decline may be worsened by hospitalization. The aim of this study was to estimate the maximal and sustained isokinetic muscle strength of lower limbs in hospitalized elderly subjects. We evaluated 43 hospitalized elderly subjects (86 ± 5 years), 28 elderly community‐dwelling control subjects (75.4 ± 6.2 years), and 25 young subjects (28.2 ± 3.7 years). Among hospitalized subjects, 30 underwent isokinetic evaluation at clinical stability (T0) and again 1 month later (T1). Maximal peak torque (MPT) of the plantarflexors was measured at 30° and 60°/s, and knee flexors and extensors at 90°/s. Evolution of the MPT and the endurance coefficient (EC) on 20 repetitions of plantarflexion at 60°/s were calculated. MPT of plantarflexors and knee flexors and extensors had improved at T1 compared with T0, in hospitalized subjects. MPT evolution and EC values during the sustained strength test revealed no decrease in strength over time in hospitalized subjects at T0 and at T1 compared with community‐dwelling control subjects and young subjects. In hospitalized subjects, the absence of an initial phase of fast decrease in muscle strength, which is observed in young subjects during the sustained strength test, could explain this result. It could be related to the modifications of muscle‐fiber composition described in elderly subjects and enhanced by hospitalization. Muscle Nerve, 2007
Effects of annealing temperature and oxygen partial pressure on the magnetoresistivity of c‐axis oriented La0.9Sr0.1MnO3+δ thin film
Authors: Xu M. , Shi Z. , Xu Z.
Published: February 2007

Using the sol–gel spin‐coating method, c‐axis oriented La0.9Sr0.1MnO3+δ thin film has been prepared. The excess oxygen δ values and Mn4+ proportions in La0.9Sr0.1MnO3+δ thin films with different annealing temperatures and oxygen partial pressures have been determined from the defect model. For La0.9Sr0.1MnO3+δ thin film, the oxygen reduction at 1073 K in 1 Pa O2 is enough to obtain samples without excess oxygen. The electrical and magnetic measurements reveal that the resistivity peak temperature TP is almost equal to the ferromagnetic transition temperature TC. The experimental results indicate that TC cannot be solely determined by the Mn4+ proportion. Probably, Mn and La site (especially Mn site) vacancies play another important role in determining TC. The excess oxygen δ in those thin films should be taken into account in investigating the magnetotransport behavior. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation and investigation (Cu–III–Se2)1–x(NbSe)x alloys (III: Ga, In) with x = 1/2
Authors: Grima‐Gallardo P. , Muñoz‐Pinto M. , Durán‐Piña S. , Delgado G. E. , Quintero M. , Briceño J. M. , Ruiz J.
Published: February 2007

Polycrystalline samples of quaternary (Cu–III–Se2)1–x (NbSe)x alloys (III: Ga, In) with x = 1/2 (nominally CuNbGaSe3 and CuNbInSe3) were prepared by the usual melt and anneal technique. The analysis showed a large solubility of Nb in the ternary structures. The unit cell parameters of CuNbGaSe3 (a = 5.617 ± 0.001 Å; c = 11.024 ± 0.003 Å; c /a = 2.02; V = 348 ± 1 Å3) and CuNbInSe3 (a = 5.779 ± 0.001 Å; c = 11.620 ± 0.003 Å; c /a = 2.01; V = 388 ± 1 Å3) were very close to those of the respective ternaries, CuGaSe2 and CuInSe2. Nevertheless, indexation of the diffraction pattern of CuNbGaSe3 suggested, for this alloy, a space group transition from I$ \bar 4 $2d to P$ \bar 4 $2c analogous to CuFeInSe3, recently reported. From DTA measurements it was found that CuNbGaSe3 and CuNbInSe3 are ordered samples with order–disorder transition temperatures of ∼976 K and ∼910 K, and melted incongruently at ∼1185 K and ∼1046 K, respectively. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Diffusion thermopower of a p‐type Si/Si1–xGex heterostructure at zero magnetic field
Authors: Huan Tran Doan , Hai Nguyen Phuc
Published: February 2007

We calculate the diffusion thermopower of the degenerate two‐dimensional hole gas in a p‐type Si/Si1–x Gex lattice mismatched heterostructure at low temperatures and zero magnetic field. The effects of possible scatterings, e.g. remote impurity, alloy disorder, interface roughness, deformation potential, and random piezoelectric on the hole mobility and the diffusion thermopower are examined. Calculated results are well fitted to the experimental data recently reported. In addition, we predict a possibility for the diffusion thermopower to change its sign as the SiGe layer thickness changes, the effect has not been discussed yet. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Excitation of dimensional resonances of magnetoelastic and elastic waves in bilayered structure
Authors: Gareeva Z. V. , Doroshenko R. A.
Published: February 2007

A study is made of the dimensional resonances of the thickness modes of shear magnetoelastic and elastic (MEE) vibrations in a bilayered structure: magnetic‐nonmagnetic dielectric. The efficiency of dimensional resonance excitation is considered. We show that the magnetic susceptibility of the thickness modes of shear MEE vibrations attains extreme values in the case when the position of an interface coincides with one half and one quarter of a MEE wavelength. The magnetic susceptibility calculated for the resonant frequencies changes in a nonmonotone way with the change of relative thickness of the magnetic layer. The form of nonmonotone regions depends on the relations between the elastic moduli of magnetic and nonmagnetic layers, the position of interface and differs for odd and even resonant frequency harmonics. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transport and magnetic properties of the diluted magnetic semiconductors Sb1.98–xV0.02Crx Te3 and Sb1.984–yV0.016Mny Te3
Authors: Drašar Č. , Kašparová J. , Lošˇták P. , Shi X. , Uher C.
Published: February 2007

We report on electrical transport and magnetic properties of quaternary single crystals of Sb1.98–x V0.02Crx Te3 and Sb1.984–y V0.016Mny Te3 with x ranging from 0 to 0.022 and y ranging from 0 to 0.034 over temperatures from 2 K to 300 K. Ternary crystals Sb2–z Vz Te3 were reported to have rather small magnetization in the ferromagnetic state due to low spin of vanadium ions. Therefore, we attempted to combine vanadium with other high‐spin elements hoping to enhance both magnetization and the Curie temperature of these diluted magnetic semiconductors (DMS) based on the Sb2Te3 matrix. While the Curie temperatures of Sb1.98–x V0.02Crx Te3 samples are comparable to that of Sb1.98V0.02Te3, we observe a significant enhancement in the remanent magnetization when Cr is co‐doped. In contrast, adding Mn to Sb1.984V0.016Te3 leads to a decrease in the Curie temperature and, at higher concentrations, to a complete suppression of ferromagnetism. Since Mn enhances the concentration of holes, its presence might seem favorable to the formation of the ferromagnetic order. In reality, the destruction of ferromagnetism in samples containing Mn is likely a result of the antiferromagnetically coupled Mn‐ion pairs. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The characteristic fragment ions and visualization of cationic starches on pulp fiber using ToF‐SIMS
Authors: Matsushita Yasuyuki , Sekiguchi Takuya , Saito Kaori , Kato Toshiyuki , Imai Takanori , Fukushima Kazuhiko
Published: February 2007

Time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) was used to investigate the distribution of cationic starch on pulp fiber. To identify the characteristic fragment ions of the cationic starches, deuterium‐labeled cationic starches were prepared and analyzed using ToF‐SIMS. The starch 2‐hydroxypropyltrimethylammonium chloride derivative generated characteristic fragments at m/z 58 and 59, which were identified as [H2CN(CH3)2]+ and [N(CH3)3]+·, respectively. The fragmentation patterns were also suggested. From the imaging analysis, the adsorption of the cationic starch on fibers was uneven on individual fibers, as well as between fibers. This may have been on account of fiber morphology and structure. On examining scanning electron microscope (SEM) images, the quaternary ammonium starch derivative (QS) did not penetrate the fiber. No migration of cationic starch was observed under various drying conditions. Copyright © 2007 John Wiley & Sons, Ltd.
Consistent with dopamine supersensitivity, RGS9 expression is diminished in the amphetamine‐treated animal model of schizophrenia and in postmortem schizophrenia brain
Authors: Seeman Philip , Ko Françoise , Jack Elaine , Greenstein Rachel , Dean Brian
Published: February 2007

It is known that RGS9‐2 gene knockout mice show supersensitivity to DA and have a marked elevation in the proportion of DA D2 receptors in the high‐affinity state for DA (D2High receptors). As this is a similar profile to that observed in the CNS from subjects with schizophrenia, we examined whether postmortem CNS tissue from subjects with the disorder and brain striata from an animal model of psychosis or schizophrenia (the amphetamine‐sensitized rat) had altered levels of RGS9‐2. The mRNA for RGS9‐2 in 29 control hippocampi was 0.185 ± 0.015 fg per fg of β‐glucuronidase mRNA (average ± SE), while that in 29 schizophrenia hippocampi was 0.145 ± 0.015 fg per fg of β‐glucuronidase mRNA (average ± SE), a reduction of 22%. Of the many receptor‐regulating genes related to G proteins, and of 11 RGS genes, RGS9‐2 was the most reduced in the amphetamine‐sensitized rat striatum. The reduced levels of RGS9‐2 expression in both an animal model of schizophrenia and a postmortem schizophrenia brain provide further evidence implicating RGS9‐2 as a candidate gene in schizophrenia. Synapse 61:303–309, 2007. © 2007 Wiley‐Liss, Inc.
Synaptophysin and insulin‐like growth factor‐1 immunostaining in the central nucleus of the inferior colliculus in adult ferrets following unilateral cochlear removal: A densitometric analysis
Authors: Alvarado Juan Carlos , Fuentes‐Santamaria Verónica , Franklin Samuel R. , Brunso‐Bechtold Judy K. , Henkel Craig K.
Published: February 2007

In the present study, unilateral cochlear ablations were performed in adult ferrets to evaluate possible time‐dependent modifications of synaptophysin and insulin‐like growth factor‐1 (IGF‐1) in the central nucleus of the inferior colliculus (CNIC). Using densitometric analysis, synaptophysin and IGF‐1 immunostaining were assessed at 1 (PA1) and 90 (PA90) days after cochlear ablation. The results demonstrated that 1 day after the lesion there was an increase in the levels of synaptophysin immunostaining bilaterally in the CNIC compared to control animals. That increase was no longer present at 90 days after the ablation. Overall levels of IGF‐1 immunostaining at PA1 were increased significantly within neurons and neuropil. However, at PA90, only IGF‐1 immunostaining contralateral to the lesion was elevated compared to control animals, although elevation was less than that observed at PA1. These results suggest that cochlear ablation appears to affect synaptophysin and IGF‐1 protein levels bilaterally in the CNIC. Synapse 61:288–302, 2007. © 2007 Wiley‐Liss, Inc.
Craniofacial variability index determined by three‐dimensional ultrasound in isolated vs. syndromal fetal cleft lip/palate
Authors: Roelfsema N. M. , Hop W. C. J. , van Adrichem L. N. A. , Wladimiroff J. W.
Published: February 2007

Objective

This study was undertaken to employ craniofacial pattern profile analysis in fetal facial clefts and to evaluate the craniofacial variability index (CVI) in distinguishing between isolated and syndromal clefts.

Methods

Three‐dimensional (3D) sonographic assessment of 16 different fetal craniofacial measurements was performed in each of eight pregnancies complicated by an isolated facial cleft and seven pregnancies with a syndromal cleft. The measurements covered various aspects of facial width, depth and height. Measured values were compared to gestational age‐specific normal values for calculation of Z‐scores and the CVI. The number of abnormal Z‐scores, i.e. < − 2 or > + 2, found among the measured values and the CVI in the group of isolated facial clefts were compared to those in the group with syndromal clefts.

Results

The CVI could be calculated in 14 of 15 fetuses (93%). More abnormal Z‐scores and a higher mean CVI were found in the group with more severe (bilateral) facial clefts. Most abnormal values were found in the facial width measurements. Syndromal cleft lip/palate was associated with significantly more abnormal Z‐scores and a higher mean CVI than isolated cleft lip/palate (P < 0.05).

Conclusion

Craniofacial variability index may be a valuable tool for distinguishing between isolated and syndromal fetal cleft lip/palate. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Leistungszuwachs in Mathematik
Authors: Becker Michael , Lüdtke Oliver , Trautwein Ulrich , Baumert Jürgen
Published: February 2007

Zusammenfassung. Die vorliegende Arbeit geht der Frage nach, ob Schüler in der Mittelstufe in Abhängigkeit von der von ihnen besuchten Schulform unterschiedliche Lernzuwächse in der Mathematikleistung aufweisen. Die Existenz dieses auch als “Schereneffekt” bezeichneten Zusammenhangs wurde in einer neueren Arbeit von Schneider und Stefanek (2004) in Frage gestellt. Anhand einer Reanalyse der nationalen längsschnittlichen Erweiterung der deutschen TIMSS-Stichprobe (N = 1864 Schüler am Ende der 7. und Ende der 8. Klasse) wurde mit Hilfe von latent change-Modellen der Leistungszuwachs in Mathematik für Gymnasiasten, Real- und Hauptschüler in einem Mehrgruppen-Strukturgleichungsmodell untersucht. Es zeigten sich differenzielle Unterschiede im Leistungszuwachs zwischen allen drei Schulformen, die auf latenter Ebene zwischen .25 und .79 Standardabweichungen betrugen. Die Befunde sprechen für die Existenz des Schereneffekts in der Sekundarstufe.
Viscous and impact demagnetization of Martian crust
Authors: Shahnas Hosein , Arkani‐Hamed Jafar
Published: February 2007

Magnetization of Martian crust has been modified by impact‐induced shock waves and viscous decay since the cessation of the core dynamo of Mars at around 4 Gyr ago. Thermal evolution models of Mars suggest that the potentially magnetic layer was about 85 km thick during the active period of the core dynamo, assuming magnetite as the major magnetic carrier. The lower boundary of the magnetic layer has gradually decreased, by a total of about 30 km, through viscous decay of magnetization. The large impacts that created the giant basins Hellas, Argyre, and Isidis have almost completely demagnetized the crust beneath the basins. The shock wave pressure produced by impacts that created craters of diameters 300–1000 km is expected to significantly demagnetize the crust beneath the craters. However, except for a few craters, there is no signature of appreciable demagnetization. This implies that either the magnetic carriers have high coercivity and have resisted demagnetization, or magnetic source bodies are deep seated, or they have acquired magnetization after the intensive impact cratering period. An alternate possibility is that the scaling laws proposed for small craters do not apply to the large craters considered in this paper.
Descent of the ancient Farallon slab drives localized mantle flow below the New Madrid seismic zone
Authors: Forte A. M. , Mitrovica J. X. , Moucha R. , Simmons N. A. , Grand S. P.
Published: February 2007

The great earthquake sequence that occurred in the central Mississippi River Valley during the winter of 1811–1812 is unprecedented in the historical record of seismicity within stable continental plate interiors. We show, using viscous flow models based on high resolution seismic tomography, that the descent of the ancient Farallon slab into the deep mantle beneath central North America induces a highly localized flow directly below the New Madrid seismic zone (NMSZ). This localization arises because of structural variability in the Farallon slab and the low‐viscosity of the sub‐lithospheric upper mantle, and it represents a heretofore unrecognized and possibly significant driving mechanism for the enigmatic intraplate seismicity.
Nucleophosmin acts as a novel AP2α‐binding transcriptional corepressor during cell differentiation
Authors: Liu Hsuan , Tan Bertrand Chin‐Ming , Tseng Kai Hung , Chuang Ching Ping , Yeh Chun‐Wei , Chen Kwang‐Den , Lee Sheng‐Chung , Yung Benjamin Yat‐Ming
Published: February 2007

Nucleophosmin (NPM) is an important nucleolar phosphoprotein with pleiotropic functions in various cellular processes. In this study, we have further examined the largely uncharacterized role of NPM in transcriptional regulation by uncovering novel NPM‐binding transcriptional factors. Among potential interactors, we found that activating protein transcription factor 2 (AP2)α forms a complex with NPM during retinoic‐acid‐induced cell differentiation. We show that this complex is recruited to the promoters of certain retinoic‐acid‐responsive genes, including NPM itself. Such binding of AP2α, and consequent recruitment of NPM, is selective and dependent on a consensus AP2α‐binding sequence. Remarkably, suppression of NPM by RNA interference alleviates the repression of gene expression mediated by retinoic acid and AP2α. Our findings further show that, on promoter binding, NPM probably exerts its repressive effect by inducing a change in local chromatin structure that also engages histone deacetylases. This study unveils a hitherto unrecognized transcriptional corepressor function of the NPM protein, and highlights a novel mechanism by which NPM regulates cell growth and differentiation.
Electric field distribution within a metallic cylindrical specimen for the case of an ideal two-probe impedance measurement
Authors: Kelekanjeri V. Siva Kumar G. , Gerhardt Rosario A.
Published: February 2007

A closed form analytical solution for the electric field distribution inside a metallic cylindrical disk specimen has been derived for the problem of a two-probe impedance measurement. A two-probe impedance measurement can be treated as current injection and extraction by means of source and sink electrodes that are placed on opposite sides of a specimen. The analytical formulation is based on Maxwell’s equations for conductors and the derivation has been conducted on the premise of continuum considerations within the specimen. The derived field expressions for axial [Ez(r,z)] and radial [Er(r,z)] fields are expressed in terms of Bessel series. As an extension to this problem, a semi-infinite solution is also given for the case of an infinitely long cylinder. The analytical solutions thus derived have been verified by computer simulations using a commercially available finite element package. The electric field distributions inside the specimen obtained via analytical and finite element solutions are in excellent agreement with each other. The dependence of skin-effect and constriction behaviors on specimen geometry (radius r0 and thickness t0) and contact radius of the electrode (rc) has been investigated by varying them in a systematic fashion. The skin-effect behavior at high frequencies is strictly a function of the dimensions of the disk (r0,t0) and is independent of the contact radius of the electrodes (rc). The constriction behavior, however, is predominantly governed by rc, although it depends on all three geometric parameters. Lastly, the idea of a limiting thickness (t0,lim) and a limiting field profile ( ∣Ez,lim∣z=t0,lim∕2) is discussed so as to determine the range of applicability of the analytical solutions. The analytical solution derived for the disk shows good agreement with the finite element solutions for all values of t0, while the semi-infinite solution is only valid for large values of t0.
Real-time kymographic imaging for visualizing human vocal-fold vibratory function
Authors: Qiu Qingjun , Schutte Harm K.
Published: February 2007

A stand-alone kymographic system for visualizing human vocal-fold vibration in real time is presented. By using a dual charge-coupled-device construction, the system not only provides kymographic images but also simultaneously presents structural images for navigating the endoscope to a desired position. With a temporal resolution of 7200lines∕s, the kymographic imaging produces a sufficient speed to investigate most types of vocal-fold vibrations. Moreover, by buffering the kymographic images during the vertical blanking periods, the system can retrieve an uninterrupted kymographic image sequence even though the television standard is used. The results from preliminary clinical evaluation present evidence that the real-time kymographic imaging substantially reduces the time required for functional evaluation of the vocal-fold vibrations.
Left- and right-handed neutrinos and Baryon-Lepton masses
Authors: Sen Dipak K.
Published: February 2007

The self-dual and anti-self-dual parts of the electromagnetic field tensor satisfying the vacuum Maxwell equations are shown to be related in a covariant manner to a left-handed and right-handed two-component Weyl neutrino νL and νR, respectively. A simple quantum mechanical analysis of a composite νL−νR system with a certain interaction shows that such a model can exhibit a two-fold branching and defect in the total energy of the system, which could then be interpreted as Baryon and Lepton mass formation.
Strain-induced electronic energy changes in multilayered InGaAs∕GaAs quantum wire structures
Authors: Ma Zhixun , Holden Todd , Wang Zhiming M. , Salamo Gregory J. , Malikova Lyudmila , Mao Samuel S.
Published: February 2007

Electronic states of layered InGaAs∕GaAs(001) quantum wire and quantum dot chain structures have been investigated by electroreflectance and surface photovoltage spectroscopy. Band-gap shrinkage and heavy-hole/light-hole state splitting have been observed in the GaAs barrier material. This can be understood by shear strain existing in the GaAs barrier due to strain relaxation and anisotropy within the wires or dot chains. By comparing the experimental results with theoretical calculations, we found that the strain relaxation in the direction perpendicular to the wires or the dot chains has a stronger effect on the heavy-hole–light-hole splitting than on band-gap modification in the InGaAs wires and dot chains. The piezoelectric field induced by the shear strain is also discussed.
Experimental evidence on quantum well–quantum dash energy transfer in tunnel injection structures for 1.55μm emission
Authors: Sęk G. , Poloczek P. , Podemski P. , Kudrawiec R. , Misiewicz J. , Somers A. , Hein S. , Höfling S. , Forchel A.
Published: February 2007

Here comes a report on the investigation of the energy transfer in InP-based tunnel injection structures, consisting of InAs∕InAlGaAs quantum dashes (QDashes) and an InGaAs∕InAlGaAs quantum well (QW), designed for 1.55μm emission at room temperature. Temperature dependent photoluminescence excitation (PLE) spectroscopy was used to experimentally confirm that the carriers created in the well reach the quantum dash layer by the tunneling through a thin InAlAs∕InAlGaAs barrier and recombine there radiatively. A measurable QW-QDash energy transfer has been detected up to 130K. The electronic structure of the whole complex system obtained by modulation spectroscopy exhibits full conformity with the PLE measurement results.
Gas phase spectra of all-benzenoid polycyclic aromatic hydrocarbons: Triphenylene
Authors: Kokkin Damian L. , Reilly Neil J. , Troy Tyler P. , Nauta Klaas , Schmidt Timothy W.
Published: February 2007

The jet-cooled laser-induced fluorescence and dispersed fluorescence spectra of the S1(A1′)←S0(A1′) transition of triphenylene are reported. The spectra exhibit false origins of e′ symmetry which are modeled by performing calculations of Herzberg-Teller coupling using time-dependent density functional theory. It is found that this level of theory reproduces the main features of the observed spectra. The oscillator strength of the strongest band is calculated to be f=7×10−4. From a combination of theory and the observed upper state lifetime of 41ns, an estimate of the fluorescence yield is made of ΦF=0.084, in agreement with previous studies in the condensed phase.
Size dependence of melting of GaN nanowires with triangular cross sections
Authors: Wang Zhiguo , Zu Xiaotao , Gao Fei , Weber William J.
Published: February 2007

Molecular dynamics simulations have been used to study the melting of GaN nanowires with triangular cross sections. The variation in potential energy as a function of the cross-sectional area of GaN nanowires, along with the atomic configuration, is used to monitor the phase transition. The thermal stability of GaN nanowires is strongly size dependent. The melting temperature of the GaN nanowires increases with increasing cross-sectional area to a saturation value. Melting of the nanowires is initiated at the surface edges formed by the triangular shape and then spreads across the nanowire surface. As temperature increases, the melting expands into the inner regions of the nanowires.
Polarized Raman scattering of Ge nanocrystals embedded in a-SiO2
Authors: Yang Y. M. , Yang L. W. , Chu Paul K.
Published: February 2007

Ge nanocrystals randomly dispersed in amorphous silica films were prepared by magnetron cosputtering and postannealing to investigate the polarization characteristics of Raman scattering from the Ge nanocrystals. Two acoustic vibrational modes observed in the low-frequency Raman spectra were shown by theoretical calculation based on the isotropic continuum elasticity theory to be the torsional modes activated by elastic anisotropy and the nonspherical shape of the Ge nanocrystals. Enhanced depolarized scattering was also observed from the optical phonons of the Ge nanocrystals.
Effect of Al-trace degradation on Joule heating during electromigration in flip-chip solder joints
Authors: Liang S. W. , Chiu S. H. , Chen Chih
Published: February 2007

This study investigates the mechanism for the abrupt increase in temperature at later stages of electromigration in flip-chip solder joints. It is found that electromigration also occurs in Al traces when stressed by 0.6A at 100°C. Three-dimensional thermoelectrical simulation by finite element analysis was carried out to simulate the temperature distribution in solder joints with and without degradation of the Al trace. It is found that the degradation of the Al trace has substantial effect on the Joule heating of solder joints. This model can explain the serious Joule heating effect in the later stages of electromigration.
Memory and nonlocal effects in heat transport: From diffusive to ballistic regimes
Authors: Alvarez F. X. , Jou D.
Published: February 2007

The authors discuss a generalized transport model including memory and nonlocal effects, which aims to describe the transition of heat transport from the diffusive regime to the ballistic regime. By using an effective thermal conductivity depending on the Knudsen number, they describe in a single equation the behavior of conductivity in terms of the system size and a reduction in the limit flux through nanoscale devices.
Complete polarization analysis of extreme ultraviolet radiation with a broadband phase retarder and analyzer
Authors: Wang Zhanshan , Wang Hongchang , Zhu Jingtao , Zhang Zhong , Wang Fengli , Xu Yao , Zhang Shumin , Wu Wenjuan , Chen Lingyan , Michette Alan G. , Pfauntsch Slawka J. , Powell A. Keith , Schäfers Franz , Gaupp Andreas , Cui Mingqi , Sun Lijuan , MacDonald Mike
Published: February 2007

The polarization state of the BESSY UE56/1-PGM beamline radiation in the broad wavelength range of 12.7–15.5nm was measured using a molybdenum/silicon transmission phase retarder and a reflection analyzer with aperiodic multilayer interference structures, which can broaden the spectral response of these optical elements. The characteristics of the circular polarized undulator radiation, as well as the polarization properties of the two polarizing elements, were determined by a complete polarization analysis. Furthermore, the polarization of the radiation as a function of the undulator shift setting was also measured at the wavelength of 13.1nm by use of the broadband phase retarder-analyzer pair.
Intrinsic electric fields in AlGaN quantum wells
Authors: Marcinkevičius S. , Pinos A. , Liu K. , Veksler D. , Shur M. S. , Zhang J. , Gaska R.
Published: February 2007

Intrinsic electric fields in AlxGa1−xN∕AlyGa1−yN quantum wells embedded into p-i-n structures are studied using photoluminescence experiments. Spectral shifts induced by external bias and screening by photoexcited carriers allow evaluating the intrinsic fields caused by piezoelectric and spontaneous polarizations. In quantum wells with low Al content, the field is about 1MV∕cm, which is in agreement with theoretical estimations. For high Al molar fractions (35% well, 50% barrier), the extracted intrinsic field is lower and, most importantly, has the opposite sign to that predicted by the theory.
An SGK1 site in WNK4 regulates Na
+
channel and K
+
channel activity and has implications for aldosterone signaling and K
+
homeostasis
Authors: Ring Aaron M. , Leng Qiang , Rinehart Jesse , Wilson Frederick H. , Kahle Kristopher T. , Hebert Steven C. , Lifton Richard P.
Published: February 2007

The steroid hormone aldosterone is secreted both in the setting of intravascular volume depletion and hyperkalemia, raising the question of how the kidney maximizes NaCl reabsorption in the former state while maximizing K
+
secretion in the latter. Mutations in WNK4 cause pseudohypoaldosteronism type II (PHAII), a disease featuring increased renal NaCl reabsorption and impaired K
+
secretion. PHAII-mutant WNK4 achieves these effects by increasing activity of the Na-Cl cotransporter (NCC) and the Na
+
channel ENaC while concurrently inhibiting the renal outer medullary K
+
channel (ROMK). We now describe a functional state for WNK4 that promotes increased, rather than decreased, K
+
secretion. We show that WNK4 is phosphorylated by SGK1, a mediator of aldosterone signaling. Whereas wild-type WNK4 inhibits the activity of both ENaC and ROMK, a WNK4 mutation that mimics phosphorylation at the SGK1 site (WNK4
S1169D
) alleviates inhibition of both channels. The net result of these effects in the kidney would be increased K
+
secretion, because of both increased electrogenic Na
+
reabsorption and increased apical membrane K
+
permeability. Thus, modification at the PHAII and SGK1 sites in WNK4 impart opposite effects on K
+
secretion, decreasing or increasing ROMK activity and net K
+
secretion, respectively. This functional state for WNK4 would thus promote the desired physiologic response to hyperkalemia, and the fact that it is induced downstream of aldosterone signaling implicates WNK4 in the physiologic response to aldosterone with hyperkalemia. Together, the different states of WNK4 allow the kidney to provide distinct and appropriate integrated responses to intravascular volume depletion and hyperkalemia.
A core transcriptional network for early mesoderm development in Drosophila melanogaster
Authors: Sandmann Thomas , Girardot Charles , Brehme Marc , Tongprasit Waraporn , Stolc Viktor , Furlong Eileen E.M.
Published: February 2007

Embryogenesis is controlled by large gene-regulatory networks, which generate spatially and temporally refined patterns of gene expression. Here, we report the characteristics of the regulatory network orchestrating early mesodermal development in the fruitfly Drosophila, where the transcription factor Twist is both necessary and sufficient to drive development. Through the integration of chromatin immunoprecipitation followed by microarray analysis (ChIP-on-chip) experiments during discrete time periods with computational approaches, we identified >2000 Twist-bound cis-regulatory modules (CRMs) and almost 500 direct target genes. Unexpectedly, Twist regulates an almost complete cassette of genes required for cell proliferation in addition to genes essential for morophogenesis and cell migration. Twist targets almost 25% of all annotated Drosophila transcription factors, which may represent the entire set of regulators necessary for the early development of this system. By combining in vivo binding data from Twist, Mef2, Tinman, and Dorsal we have constructed an initial transcriptional network of early mesoderm development. The network topology reveals extensive combinatorial binding, feed-forward regulation, and complex logical outputs as prevalent features. In addition to binary activation and repression, we suggest that Twist binds to almost all mesodermal CRMs to provide the competence to integrate inputs from more specialized transcription factors.
Evolutionary conservation of cell migration genes: from nematode neurons to vertebrate neural crest
Authors: Kee Yun , Hwang Byung Joon , Sternberg Paul W. , Bronner-Fraser Marianne
Published: February 2007

Because migratory cells in all animals share common properties, we hypothesized that genetic networks involved in cell migration may be conserved between nematodes and vertebrates. To explore this, we performed comparative genomic analysis to identify vertebrate orthologs of genes required for hermaphrodite-specific neuron (HSN) migration in Caenoryhabditis elegans, and then examined their expression and function in the vertebrate neural crest. The results demonstrate high conservation of regulatory components involved in long-range migrations across diverse species. Although the neural crest is a vertebrate innovation, the results suggest that its migratory properties evolved by utilizing programs already present in the common vertebrate–invertebrate ancestor.
Nitrazepam as a pre medic ant in minor surgery
Authors: James M. , Fisher A.
Published: February 2007

In an attempt to quantify sedation, use was made of plasma Cortisol estimation following oral premedication with nitrazepam and the results compared with the widely used scoring method. Both methods indicate that nitrazepam produces satisfactory sedation. The results also indicate that the determination of plasma Cortisol might be a simple objective measurement capable of quantifying the sedation produced by premedication.
Pre‐operative amnesia
Authors: Pandit S. K. , Dundee J. W.
Published: February 2007

Memory for the journey to the operating theatre or intravenous induction of anaesthesia is little impaired by commonly used premedicants. Some anterograde amnesia follows the administration of hyoscine 0.4mg and opiate‐diazepam mixtures, while this occurs in about one‐quarter of the patients given diazepam‐hyoscine.
Respiratory failure in pregnancy
Authors: WOOLLAM CHRISTOPHER H. M. , HOULTON MICHAEL C. C.
Published: February 2007

A case of respiratory failure in pregnancy associated with old poliomyelitis is presented and the available methods of treatment described.
Terminal gas‐exhaust valve for a passive disposal system
Authors: MEHTA S.
Published: February 2007

A one‐way gas‐exhaust valve for use in passive disposal systems is described. The valve is explosion‐proof and it does not offer any resistance at gas flow rates of up to 30 litres/ minute. The design of the valve minimises the influence of wind velocities on pressure fluctuation in the disposal system.
Intravenous sedation and regional analgesia
Authors: MD Jon Gjessing , Tomlin P. J.
Published: February 2007

A double‐blind study of 229 patients with the use of intravenous diazepam as compared with a placebo to produce sedation during local analgesia showed that significantly improved sedation occurred when diazepam was used. The diazepam was dissolved in cremophor and this reduced the pain of intravenous injection of the diazepam. One patient who received Cremophor only, showed a moderately severe allergic reaction. It is suggested that a small test dose should always be given before giving any drug which is dissolved in Cremophor.
Marcus Gunn Syndrome associated with an unusual oculo‐cardiac reflex
Authors: KWIK RAYMOND S.H.
Published: February 2007

The Marcus Gunn Syndrome is discussed. It is postulated that an atypical oculocardiac reflex is easily initiated in these patients so that precautions must be taken for its prevention and early detection.

Marcus Gunn first described the syndrome in 1883.1 His patient had a congenital ptosis of the left upper eyelid. Paradoxical lid retraction was evoked by movement of the jaw. Consequently the syndrome also became known as the ‘jaw‐winking’ syndrome. Other varieties of the Marcus Gunn syndrome have also been described.2

The pathogenesis of this syndrome seems to be the presence of abnormal central connexions between the trigeminal and oculomotor cranial nerves which supply the external pterygoid and the levator palpebrae superioris muscles.

The importance of the recognition of the oculocardiac reflex in patients undergoing eye surgery nnder anaesthesia is well known to anaesthetists and to eye surgeons.

The occurrence of this reflex in patients undergoing surgery on the eyelids has been reported previously.3 This paper describes a patient with the Marcus Gunn Syndrome who underwent three operations on the left upper eyelid and who exhibited unusual manifestations of the oculocardiac reflex.
Editorial
Authors: Shakespeare William , Horsey P.J.
Published: February 2007

‘Throw physic to the dogs; I'll none of it’
Thiopentone and fazadinium crash induction
Authors: BARR A. MARSHALL , THORNLEY B.A.
Published: February 2007

A method of crash induction using fazadinium and thiopentone was studied in 100 patients not genuinely at risk from regurgitation. Speed and ease of intubation compared well with a previous study using pancuronium.1 Cardiorascular stability was not as good as with pancuronium and tachycardia was the major concern. Fourteen patients were assessed as ‘difficult’ to reverse and three recurarised.
Perioperative hazards in myotonic dystrophy
Authors: MUDGE BARBARA J. , TAYLOR PETER B. , VANDERSPEK ABRAHAM F. L.
Published: February 2007

A 32‐year‐old man with myotonic dystrophy underwent a thoracotomy for removal of a mediastinal thymoma. Pre‐operative examination revealed features of myotonic dystrophy, the only other abnormality was mild restrictive pulmonary disease. Anaesthesia was induced with thiopentone and maintained with enflurane, nitrous oxide, oxygen and curare. Following surgery, the patient was mechanically ventilated for several hours and remained intubated for 9 hours. The anaesthesia and surgery were tolerated well; however, postoperative complications included refractory dysrhythmias, hypoxia, pneumoccocal pneumonia and pulmonary emboli. More intensive preoperative pulmonary evaluation and physiotherapy coupled with more aggressive postoperative pulmonary care might have resulted in a smoother recovery phase.
An anaesthetic scavenging system for paediatric and adult use
Authors: HATCH DAVID J. , MILES ROGER , WAGSTAFF MALCOLM
Published: February 2007

A scavenging dish is described which removes large volumes of contaminated air. It can be placed close to the open‐tailed bag of the paediatric T piece to provide a safe, convenient and efficient scavenger without any modification of the patient circuit. Measurements before and after installation have shown it to be capable of reducing nitrous oxide levels in the operating theatre to between 40 and 0 parts per million. The dish has been incorporated into a scavenging system which can also be used with a standard antipollution valve or ventilator exhaust port.
The effect of alcohol on the pulmonary embolic syndrome
Authors: Alexander John P. , Barron David W.
Published: February 2007

Total hip replacement surgery was carried out on 100 patients with an anaesthetic technique which was identical in all respects, except that fifty patients were given 5% dextrose while the other fifty received alcohol 0.5 mg/kg in addition. Patients were allocated to one or other group by random selection. There was no evidence that alcohol afforded any protection against the pulmonary embolic syndrome, nor did it appear to increase blood loss.
Recovery comparison between enflurane and halothane techniques A study of outpatients undergoing cystoscopy
Authors: Padfield Adrian , Mullins R.C.
Published: February 2007

A comparison of recovery from either halothane or enflurane with nitrous oxide and oxygen after induction with Althesin by outpatients in a cystoscopy clinic is presented. The recovery rate was scored by the recovery room nurses, who were ignorant of which agent had been used. Recovery after enflurane was quicker than after halothane.
Caudal extradural injection for the treatment of low back pain
Authors: Gordon John
Published: February 2007

The technique of large volume caudal extradural injection of a solution containing bupivacaine hydrochloride, hydrocortisone acetate and methylprednisolone acetate for low back pain is described.

The results of 500 such injections are reviewed. The technique provides a rapid safe method for the treatment of low back pain. Pain was relieved in over half the patients treated by a single injection.
The journey and the arrival
Authors: PARKHOUSE JAMES
Published: February 2007

The present motivation, recruitment and career structure of the specialty of anaesthesia in England and Wales in relation to training and the needs of the National Health Service is examined and assessed. Proposals are made for reorganisation and future development.
Plasma cholinesterase changes during pregnancy
Authors: EVANS R.T. , WROE J.M.
Published: February 2007

Cholinesterase activities were measured on serum from 941 pregnant women distributed evenly throughout the 40 weeks of gestation. A rapid fall has been shown to occur during the first trimester to a level which did not alter significantly during the remainder of pregnancy. Even lower values were observed in 105 patients examined during the first 7 days following delivery.

Enzyme activity was used to determine the probable incidence of a prolonged reaction to suxamethonium in obstetric patients. The risk was greatest in the immediate post partum period affecting 11% of the patients investigated.
Anaesthesia in Von Gierke's disease
Authors: BEVAN JOAN C.
Published: February 2007

A case report of a patient with Von Gierke's (glycogen storage disease Cori type (1)1 disease who required femoral osteotomy is presented. Current techniques of management of this condition which are likely to improve the outcome of general anaesthesia and surgery are discussed.
Cross‐infection from contaminated anaesthetic equipment
Authors: NIELSEN HENRIK , JACOBSEN JAN B. , STOKKE DAG B. , BRINKLØV MORTEN M. , CHRISTENSEN KURT N.
Published: February 2007

A definite relationship between the use of contaminated anaesthetic equipment and subsequent pulmonary infection remains to be established. There is however indirect and circumstantial evidence suggesting that cross‐infection may occur, and further an increased susceptibility of surgical patients to pulmonary infections has been demonstrated. Decontamination should be recommended before the equipment is re‐used. Pasteurisation may prove sufficient and this can be obtained employing a specially designed dish‐washing machine.