bluuebunny/crossref_metadata_2025 huggingface dataset:
Acute elevation of plasma non-esterified fatty acids increases pulse wave velocity and induces peripheral vasodilation in humansin vivo
Authors: Riksen Niels P. , Bosselaar Marlies , Bakker Stephan J.L. , Heine Robert J. , Rongen Gerard A. , Tack Cees J. , Smits Paul
Published: June 2007

Plasma NEFA (non-esterified fatty acid) concentrations are elevated in patients with obesity. In the present study we first aimed to provide an integral haemodynamic profile of elevated plasma NEFAs by the simultaneous assessment of blood pressure, pulse wave velocity, FBF (forearm blood flow) and sympathetic nervous system activity during acute elevation of NEFAs. Secondly, we hypothesized that NEFA-induced vasodilation is mediated by adenosine receptor stimulation. In a randomized cross-over trial in healthy subjects, Intralipid® was infused for 2 h to elevate plasma NEFAs. Glycerol was administered as the Control infusion. We assessed blood pressure, pulse wave velocity, FBF (using venous occlusion plethysmography) and sympathetic nervous system activity by measurement of noradrenaline and adrenaline. During the last 15 min of Intralipid®/Control infusion, the adenosine receptor antagonist caffeine (90 μg·min−1·dl−1) was administered into the brachial artery of the non-dominant arm. Compared with Control infusion, Intralipid® increased pulse wave velocity, SBP (systolic blood pressure) and pulse pressure, as well as FBF (from 1.8±0.2 to 2.7±0.6 and from 2.3±0.2 to 2.7±0.6 ml·min−1·dl−1 for Intralipid® compared with Control infusion; P<0.05, n=9). Although in a positive control study caffeine attenuated adenosine-induced forearm vasodilation (P<0.01, n=6), caffeine had no effect on Intralipid®-induced vasodilation (P=0.5). In conclusion, elevation of plasma NEFA levels increased pulse wave velocity, SBP and pulse pressure. FBF was also increased, either by baroreflex-mediated inhibition of the sympathetic nervous system or by a direct vasodilating effect of NEFAs. As the adenosine receptor antagonist caffeine could not antagonize the vasodilator response, this response is not mediated by adenosine receptor stimulation.
IUPAC-NIST Solubility Data Series. 82. Alcohols with Water—Revised and Updated: Part 3. C6 Alcohols with Water
Authors: Goral Marian , Wisniewska-Goclowska Barbara
Published: June 2007

The solubility and related liquid–liquid equilibria in systems C6 alcohols+water are exhaustively and critically reviewed. Reports of experimental determination of solubility in 13 chemically distinct binary systems that appeared in the primary literature prior to end of 2004 are compiled. 12 systems are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of the all experimental data for a given homologous series of saturated alcohols was used.
IUPAC-NIST Solubility Data Series. 82. Alcohols with Water—Revised and Updated: Part 4. C7 Alcohols with Water
Authors: Goral Marian , Wisniewska-Goclowska Barbara
Published: June 2007

The mutual solubility and related liquid-liquid equilibria of C7 alcohols with water are exhaustively and critically reviewed. Reports of experimental determination of solubility in 20 chemically distinct binary systems that appeared in the primary literature prior to end of 2004 are compiled. For 14 systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of the all experimental data for a given homologous series of saturated alcohols was used.
Strain enhancement during annealing of GaAsN alloys
Authors: Zhuang Q. D. , Krier A. , Stanley C. R.
Published: June 2007

We have investigated the effect of rapid thermal annealing (RTA) on the optical and structural properties of GaAsN alloys using photoluminescence (PL) and double-crystal x-ray diffraction. We observe a significant anomalous strain enhancement during RTA and a blueshift of the PL peak energy accompanied by a reduction in the emission linewidth. The PL features are attributed to an improvement in the homogeneity of the alloy, and the strain enhancement reflects a change in N-related complexes during annealing. Based on a defect model, an interstitial nitrogen concentration of 1.8×1019 cm−3 is deduced prior to annealing.
Ultraviolet laser-induced submicron spatially resolved superhydrophilicity on single crystal lithium niobate surfaces
Authors: Muir A. C. , Mailis S. , Eason R. W.
Published: June 2007

Lithium niobate crystal surfaces become superhydrophilic after ultraviolet laser irradiation. The crystal surface hydrophilicity, which was assessed by the contact angle of a sessile drop of de-ionized water, was found to undergo a transition from mildly hydrophobic (contact angle θE≈50°) to a superhydrophilic state (θE<5°). Patterning of the hydrophilicity at the micron and submicron ranges has been achieved by spatially modulating the illuminating laser beam.
Thermally activated delayed fluorescence as a cycling process between excited singlet and triplet states: Application to the fullerenes
Authors: Baleizão Carlos , Berberan-Santos Mário N.
Published: June 2007

In efficient thermally activated delayed fluorescence (TADF) the excited chromophore alternates randomly between the singlet and triplet manifolds a large number of times before emission occurs. In this work, the average number of cycles n¯ is obtained and is shown to have a simple experimental meaning: n¯+1 is the intensification factor of the prompt fluorescence intensity, owing to the occurrence of TADF. A new method of data analysis for the determination of the quantum yield of triplet formation, combining steady-state and time-resolved data in a single plot, is also presented. Application of the theoretical results to the TADF of [70]fullerenes shows a general good agreement between different methods of fluorescence analysis and allows the determination of several photophysical parameters.
Sulfur atom exchange in the reaction of SH radicals with S atoms
Authors: Francisco Joseph S.
Published: June 2007

The structural and energetic properties of the HSS→SSH transition state are examined using the single and double coupled-cluster method. The energy change for the isomerization reaction is estimated to be 31.7±1kcalmol−1. The results suggest that the reaction between SH radicals and S atoms should isotopically exchange because the isomerization barrier is significantly less than the S–S bond dissociation energy in the HSS radical.
Domain microstructures and ferroelectric phase transition in Pb0.35Sr0.65TiO3 films studied by second harmonic generation in reflection geometry
Authors: Liu S. W. , Jolly S. , Xiao Min , Yuan Z. , Liu J. , Chen C. L. , Zhu Wenkai
Published: June 2007

Second harmonic generation (SHG) measurements were performed in the reflection geometry using the femtosecond Ti:sapphire laser at the wavelength of 810nm for Pb0.35Sr0.65TiO3 films, which were epitaxially deposited on (001) MgO substrates by pulsed laser ablation under different oxygen pressures. We formulated the procedures to measure the ratios of the compensated fractions of both c domains and in-plane domains and the ratios of the components of the nonlinear susceptibility tensor under only a non-normal incidence of the fundamental beam. We applied this technique to characterize the domain microstructures of the Pb0.35Sr0.65TiO3 films at three typical temperatures (78, 150, and 300K) and found these films to exhibit a larger compensated fraction of c domains. The ratios of the components of the nonlinear susceptibility tensor were calculated to be relatively constant regardless of the temperature and the oxygen pressure. On the other hand, their SHG intensities were found to increase as the oxygen pressure goes lower, which is attributed to the higher density of the oxygen vacancies in the films. These films also exhibit the diffuselike phase transition in a very wide temperature range, which is attributed to the structural inhomogeneity and the nonuniform distribution of Pb2+ and Sr2+ in the Pb0.35Sr0.65TiO3 films.
Screen-printed multicrystalline silicon solar cells with porous silicon antireflective layer formed by electrochemical etching
Authors: Kwon Jae-Hong , Lee Soo-Hong , Ju Byeong-Kwon
Published: June 2007

The latest results on the use of porous silicon (PS) as an antireflection coating (ARC) in simplified processing for multicrystalline silicon (mc-Si) solar cells are presented. A PS layer with optimal antireflection characteristics was obtained for charge density (Q) of 5.2 C∕cm2. The weighted reflectance was reduced to 4.7% in the range of wavelengths between 400 and 1000 nm. Also, the optimization of a PS selective emitter formation results in a 13.2% efficiency mc-Si cell (2×2 cm2) with the electroplating method. Specific attention is given to the implementation of a PS ARC into a commercially compatible screen-printed solar cell process.
Raman spectroscopy study of Zn1−xMnxSe thin films under high-pressure
Authors: Lin Chih-Ming , Chuu Der-San
Published: June 2007

Raman spectroscopy was used to study phase transitions of substrate-free Zn1−xMnxSe thin films, x=0.07, 0.17, and 0.29, under high pressure up around 20.0 GPa at ambient temperature. One Raman mode, transverse optical split mode, was observed before metallization at 2.9±1.0, 2.4±0.8, and 2.1±0.6 GPa for Zn0.71Mn0.29Se, Zn0.83Mn0.17Se, and Zn0.93Mn0.07Se thin films, respectively. The semiconductor-metallic transition pressure for Zn0.71Mn0.29Se, Zn0.83Mn0.17Se, and Zn0.93Mn0.07Se thin films was observed at 9.4±0.4, 10.9±0.6, and 11.7±0.2 GPa, respectively. It was found that the relation of the ionicity and the reduction of the pressure in transition from semiconductor to metal phase for Zn1−xMnxSe thin films was not the same as that of bulk crystals. The percentage of the increasing of the Grüneison parameter of longitudinal optical mode for semiconductor to metal phase transition might be the important factor inherently related to the reduction of phase transition pressure for substrate-free Zn1−xMnxSe thin film systems.
Formation of atomic-scale graded structure in Se-Te semiconductor under strong gravitational field
Authors: Huang Xinsheng , Ono Masao , Ueno Hideto , Iguchi Yusuke , Tomita Takeshi , Okayasu Satoru , Mashimo Tsutomu
Published: June 2007

A large linearly graded structure on atomic scale up to 88 at. %/mm with oriented grown crystals was formed in selenium-tellurium (Se-Te) semiconductor using a strong gravitational field of one million G level at 260 °C. The lattice constants and the binding energies of Se and Te 3d electrons continuously changed along the direction of gravity accordingly, which indicated the formation of the graded band gap structure. The grown crystals showed the crystalline orientation with the c axis of hexagonal structure roughly perpendicular to the direction of gravity. It was found that the diffusion coefficient of sedimentation was larger than that of normal diffusion by more than 100 times, which suggested a different diffusion mechanism from the normal vacancy mechanism.
Magnetic forces on current circuits when there are no photons in the electromagnetic field
Authors: Moses Harry E.
Published: June 2007

In a previous paper we considered the quantized electromagnetic field when there were no photons. Since the number operator for the quantized electromagnetic field does not commute with the field operators, giving an eigenvalue to the number operator means that measurements of the field operators in an interval cannot be made exactly. One must content oneself with obtaining the probability distributions for the fields. In the present paper we shall carry out similar calculations for the magnetic fields.
Parameterization of the band gap energy for GaNxAs1−x−zPz alloys
Authors: Kudrawiec R.
Published: June 2007

It is proposed here that the band gap energy for GaNxAs1−x−zPz (type II alloys) can be parameterized within a method which was demonstrated for Ga1−yInyNxAs1−x (type I alloys) [J. Appl. Phys. 101, 023522 (2007)]. This method requires knowledge of the band gap energy of GaNxAs1−x and GaNxP1−x as well as a bowing parameter. It has been observed that the obtained band gap predictions are in good agreement with available experimental data for GaNAsP.
X-ray diffraction study on an InGaN∕GaN quantum-well structure of prestrained growth
Authors: Shiao Wen-Yu , Huang Chi-Feng , Tang Tsung-Yi , Huang Jeng-Jie , Lu Yen-Cheng , Chen Cheng-Yen , Chen Yung-Sheng , Yang C. C.
Published: June 2007

We compare the x-ray diffraction (XRD) results of two InGaN∕GaN quantum-well (QW) structures to observe the effects of prestrained growth by depositing a low-indium QW before the growth of five high-indium QWs. From the results of reciprocal space mapping, we observe the fully strained condition in the QWs of the control sample. However, in the sample of prestrained growth, the average strain is partially relaxed. By using an XRD fitting algorithm for calibrating QW parameters, we obtain reasonable values for the compositions and thicknesses of the QWs in both samples. In particular, by assuming a nonuniform strain relaxation distribution among the five high-indium QWs in the prestrained sample, we obtain reasonable composition variations among the QWs. The high-indium QW closest to the low-indium one is most strain-relaxed and has the highest indium incorporation, leading to the longest-wavelength emission. The observed red shift with increasing electron penetration depth in the cathodo-luminescence spectra of the prestrained sample is consistent with the distributions of calibrated strain relaxation and indium composition. The results of high-resolution transmission electron microscopy and effective band gap calculation also agree with the above conclusions.
All fiber based multispeckle modality endoscopic system for imaging medical cavities
Authors: Murukeshan V. M. , Sujatha N.
Published: June 2007

Disease detection in body cavities, such as the detection of abnormal growths in the colon path, has been illustrated here using an image fiber guided catheter based multispeckle modality endoscopic system. An all fiber-optic approach for the illumination and imaging of the inner cavity walls is adopted here. An endoscope probe to carry the illumination fibers as well as the imaging lens–image fiber unit is designed and custom fabricated in order to operate the probe in its various direction sensitive configurations. This is facilitated by the selection of suitable optical elements such as beam combiner and biprism at the probe proximal end. Experimental investigations were carried out using the endoscope system employing phantom model of colon as the test specimen that has normal and abnormal (representing growth) regions and the obtained results indicated the system effectiveness in identifying the abnormal growths at an early stage.
Subnormalized states and trace-nonincreasing maps
Authors: Cappellini Valerio , Sommers Hans-Jürgen , Życzkowski Karol
Published: June 2007

We investigate the set of completely positive, trace-nonincreasing linear maps acting on the set MN of mixed quantum states of size N. Extremal point of this set of maps are characterized and its volume with respect to the Hilbert-Schmidt (HS) (Euclidean) measure is computed explicitly for an arbitrary N. The spectra of partially reduced rescaled dynamical matrices associated with trace-nonincreasing completely positive maps belong to the N cube inscribed in the set of subnormalized states of size N. As a by-product we derive the measure in MN induced by partial trace of mixed quantum states distributed uniformly with respect to the HS measure in MN2.
Quaternionic wave packets
Authors: De Leo Stefano , Ducati Gisele C.
Published: June 2007

We compare the behavior of a wave packet in the presence of a complex and a pure quaternionic potential step. This analysis, done for a Gaussian convolution function, sheds new light on the possibility to recognize quaternionic deviations from standard quantum mechanics.
Band alignment at the ZrO2∕Si(100) interface studied by photoelectron and x-ray absorption spectroscopy
Authors: Richter J. H. , Karlsson P. G. , Sanyal B. , Blomquist J. , Uvdal P. , Sandell A.
Published: June 2007

We present measurements of the Zr and Si core level photoelectron binding energies relative to the Fermi level and the vacuum level under a ZrO2 growth series on Si(100). It is shown that the Zr core level binding energy is most properly referenced to the local vacuum level already from the monolayer regime. This confirms the insulating properties of ZrO2. The Si core levels are referenced to the Fermi level and undergo shifts consistent with the disappearance of the mid-band-gap states originating from the (2×1) reconstruction on the clean Si(100) surface. The use of O 1s x-ray absorption spectroscopy (XAS) to determine the location of the conduction band edge of ZrO2 is discussed with the aid of ab initio calculations. It is demonstrated that the conduction band edge is located at the XAS peak position and that the position relative to the valence band can be determined by aligning the O 1s XAS spectrum to the O 1s photoelectron spectrum. The study thus establishes that photoelectron spectroscopy in conjunction with x-ray absorption spectroscopy forms a most powerful tool for studies of the band alignment at metal oxide–silicon interfaces.
X-ray pole figure analysis on columnar-structured microcrystalline silicon: Growth-induced crystallographic axial alignment in solid phase
Authors: Sobajima Yasushi , Nakano Shinya , Toyama Toshihiko , Okamoto Hiroaki , Omae Satoshi , Minemoto Takashi , Takakura Hideyuki , Hamakawa Yoshihiro
Published: June 2007

Angular distributions of crystallographic axes of the microcrystalline silicon (μc-Si) thin films have been investigated using the x-ray pole figure measurements with an emphasis on the growth-induced changes in the first growth regions of the μc-Si films. The (220) preferentially oriented μc-Si films containing columnar microstructures were prepared by plasma enhanced chemical vapor deposition with differing thicknesses. The distributions in the tilt angles of ⟨220⟩ axes from the substrate normal decreased with increasing the film thickness, particularly in the first 0.5μm growth regions. Meanwhile, such a change was not found in ⟨111⟩ axes. Moreover, the x-ray pole figure measurements were also carried out for the (111) preferentially oriented μc-Si films containing granular microstructures, revealing that no pronounced change in the tilt angles of ⟨111⟩ axes were found during the film growth. Therefore, the axial alignment should be specific to the ⟨220⟩ axes in the μc-Si films with the (220) preferential orientation. In conjunction with the other experimental results on the microstructures, the growth-induced structural changes in solid phase are discussed.
Aharonov-Bohm effect on the Poincaré disk
Authors: Lisovyy Oleg
Published: June 2007

We consider formal quantum Hamiltonian of a charged particle on the Poincaré disk in the presence of an Aharonov-Bohm magnetic vortex and a uniform magnetic field. It is shown that this Hamiltonian admits a four-parameter family of self-adjoint extensions. Its resolvent and the density of states are calculated for natural values of the extension parameters.
Nodal sets of solutions of equations involving magnetic Schrödinger operator in three dimensions
Authors: Pan Xing-Bin
Published: June 2007

It is well known that the complexity of the nodal set of a function mainly comes from the singular set on which both the function and the gradient vanish. The singular set of a real-valued solution of a linear elliptic equation has been well investigated. For a complex-valued solution of a linear equation involving a magnetic Schrödinger operator, the structure of the nodal set has not been well investigated yet excepted in the two-dimensional case. In this paper we extend the arguments of Garafalo and Lin [Indiana Univ. Math. J. 35, 245–268 (1986)] and of Han [Indiana Univ. Math. J. 43, 983–1002 (1994)] to show that the singular set of such a solution in a three-dimensional domain is countably 1-rectifiable. The functions considered in this paper include the order parameter in the Ginzburg-Landau theory of superconductivity and the eigenfunctions of the magnetic Schrödinger operator.
Exact solvability of superintegrable Benenti systems
Authors: Sergyeyev Artur
Published: June 2007

We establish quantum and classical exact solvability for two large classes of maximally superintegrable Benenti systems in n dimensions with arbitrarily large n. Namely, we solve the Hamilton-Jacobi and Schrödinger equations for the systems in question. The results obtained are illustrated for a model with the cubic potential.
Intrinsic and extrinsic origin of room temperature ferromagnetism in ZnO:Co (5at.%)
Authors: Bhatti Kanwal Preet , Chaudhary Sujeet , Pandya Dinesh K. , Kashyap Subhash C.
Published: June 2007

The high temperature magnetization behavior of an air sintered nanocrystalline ZnO:Co (5at.%) sample while it is subjected to thermal cycles in vacuum/air ambient is reported in the present paper. The pristine air sintered sample exhibits intrinsic room temperature ferromagnetism. Upon vacuum annealing, the magnetization of this sample increases significantly and the sample remains ferromagnetic up to 630°C. This has been attributed to the formation of Co clusters, and thus, the ferromagnetic ordering is extrinsic in nature. The subsequent air annealing of the vacuum annealed ZnO:Co (5at.%) sample, however, reverts back the magnetization to a value that was observed in the pristine air sintered sample. This is due to complete oxidation of the cobalt clusters. Furthermore, the sample’s magnetization at room temperature and also its temperature dependence up to 630°C remain unaffected by further annealing in vacuum or air, a feature required of a material for its device applications. The Curie temperature of this robust sample is ∼450°C.
Rectifying property and giant positive magnetoresistance of Fe3O4∕SiO2∕Si heterojunction
Authors: Qu T. L. , Zhao Y. G. , Tian H. F. , Xiong C. M. , Guo S. M. , Li J. Q.
Published: June 2007

Fe 3 O 4 ∕ Si O 2 ∕ Si heterojunction was fabricated by growing Fe3O4 film on an n-typed Si wafer with the native SiO2 buffer layer using the pulsed laser deposition. Transmission electron microcopic study shows the high quality of the heterojunction interfaces and the SiO2 layer is 2.5nm thick. This junction shows a backward diodelike rectifying behavior and an anomalously giant positive magnetoresistance (MR) for the large reverse bias voltages. The temperature dependence of MR shows a peak around the Verwey transition temperature with a maximum MR of 87% under a −2V bias voltage. The results were discussed by considering the band structure of the heterojunction and the effect of the reverse bias voltage.
Directional acoustic source by scattering acoustical elements
Authors: Håkansson Andreas , Torrent Daniel , Cervera Francisco , Sánchez-Dehesa José
Published: June 2007

Highly directional sources are desirables in a variety of fields for many applications. The authors report an inverse designed scattering acoustical element device that transforms an omnidirectional ultrasonic source into one highly directional. This two-dimensional design shows an overall better modeled performance than other previously proposed, including a half-power angular width less than 5°. The experimental demonstration is performed in the ultrasonic range, using a hydrophone as omnidirectional source and an array of alumina rods as building blocks for the scattering acoustical elements. The measured half-power angular width is 6°, a value that supports the high reliability of the designing tool.
Enhanced performance of solution-processed regioregular poly(3-hexylthiophene) thin-film transistors using planar bottom-contact architecture
Authors: Xu Mingsheng , Nagai Keita , Nakamura Masakazu , Kudo Kazuhiro , Iizuka Masaaki
Published: June 2007

The authors report on the solution-processed planar bottom-contact (pBC) organic thin-film transistors and contact effect on gate threshold voltage incorporating regioregular poly(3-hexylthiophene) active layer. By employing pBC configuration, the transistors on SiO2∕Si without surface modification show much higher mobility, lower threshold voltage, and narrower dispersion of threshold voltage when compared to the conventional bottom-contact counterparts. The high mobility and lower threshold voltage are attributed to an improved contact at the interface between the source/drain electrodes and the poly(3-hexylthiophene) active layer.
Nanostructure transition: From solid solution Ti(N,C) to nanocomposite nc-Ti(N,C)∕a-(C,CNx)
Authors: Lu Y. H. , Shen Y. G.
Published: June 2007

A nanostructure transition from solid solution (SS) Ti(N,C) to two-phase nanocrystalline (nc)-Ti(N,C)/amorphous (a)-(C,CNx) thin films was investigated using a combination of high-resolution transmission electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy. The finding of the authors is that such a nanostructure transition was strongly controlled by the relative atomic ratio x[x≡(C+N)∕Ti]. The results indicated that SS Ti(N,C) and uncompleted and completed segregated two-phase nanocomposite nc-Ti(N,C)∕a-(C,CNx) were successively formed at x⩽1.0, 1.0<x<1.2, and x⩾1.2, respectively. Increase of the x values not only decreased the grain size and promoted the formation of more [200]-oriented nanocrystallites but also produced more disorders and defects in thin films. A maximum hardness was achieved for a SS Ti(N,C) structure at x=1.0. The corresponding nanostructure transition mechanism is also discussed.
Temperature dependent photoluminescence in oxygen ion implanted and rapid thermally annealed ZnO∕ZnMgO multiple quantum wells
Authors: Wen Xiaoming , Davis Jeffrey A. , Van Dao Lap , Hannaford Peter , Coleman V. A. , Tan H. H. , Jagadish C. , Koike K. , Sasa S. , Inoue M. , Yano M.
Published: June 2007

The authors investigate the effect of oxygen implantation and rapid thermal annealing in ZnO∕ZnMgO multiple quantum wells using photoluminescence. A blueshift in the photoluminescence is observed in the implanted samples. For a low implantation dose, a significant increase of activation energy and a slight increase of the photoluminescence efficiency are observed. This is attributed to the suppression of the point defect complexes and transformation between defect structures by implantation and subsequent rapid thermal annealing. A high dose of implantation leads to lattice damage and agglomeration of defects leading to large defect clusters, which result to an increase in nonradiative recombination.
Fabrication of high performance top-gate complementary inverter using a single carbon nanotube and via a simple process
Authors: Hu Y. F. , Yao K. , Wang S. , Zhang Z. Y. , Liang X. L. , Chen Q. , Peng L.-M. , Yao Y. G. , Zhang J. , Zhou W. W. , Li Y.
Published: June 2007

High performance complementary inverters have been fabricated using single-walled carbon nanotubes. The Al2O3 top-gate dielectric is grown via first depositing an Al film followed by complete oxidation of the film. It is shown that the quality of the Al2O3 film can be significantly improved by annealing at 400°C, and stable p-type and n-type carbon nanotube field-effect transistors (CNTFETs) may be fabricated using either Pd (p-type) or Al (n-type) electrodes. High performance complementary inverter is demonstrated by integrating the p-type and n-type CNTFETs on the same carbon nanotube, and a gain of about 3.5 is achieved.
Contact to ZnO and intrinsic resistances of individual ZnO nanowires with a circular cross section
Authors: Lin Yen-Fu , Jian Wen-Bin , Wang C. P. , Suen Yuen-Wuu , Wu Zhong-Yi , Chen Fu-Rong , Kai Ji-Jung , Lin Juhn-Jong
Published: June 2007

Single crystalline ZnO nanowires (NWs) with a circular cross section and ∼40nm in diameter have been synthesized and utilized to fabricate two-contact ZnO NW devices. The electrical properties of the NW devices can be categorized into two classes according to the magnitude of their room-temperature resistances. I-V curves of low-resistance devices exhibit downward bending features and their temperature dependent resistances demonstrate thermal activation transport in the ZnO NWs. The high-resistance NW devices can be modeled as back-to-back Schottky contacts and the electron transport through the contacts reveals a variable-range-hopping mechanism.
Gene families and evolution of trehalose metabolism in plants
Authors: Lunn John E.
Published: June 2007

The genomes of Arabidopsis thaliana L., rice (Oryza sativa L.) and poplar (Populus trichocarpa Torr. & A.Gray) contain large families of genes encoding trehalose-phosphate synthase (TPS) and trehalose-phosphatase (TPP). The class I subfamily of TPS genes encodes catalytically active TPS enzymes, and is represented by only one or two genes in most species. A. thaliana is atypical in having four class I TPS genes, three of which (AtTPS2–4) encode unusual short isoforms of TPS that appear to be found only in members of the Brassicaceae family. The class II TPS genes encode TPS-like proteins with a C-terminal TPP-like domain, but there is no experimental evidence that they have any enzymatic activity and their function is unknown. Both classes of TPS gene are represented in the genomes of chlorophyte algae (Ostreococcus species) and non-flowering plants [Physcomitrella patens (Hedw.) Bruch & Schimp.(B.S.G.) and Selaginella moellendorffii (Hieron. in Engl. & Prantl.)]. This survey shows that the gene families encoding the enzymes of trehalose metabolism are very ancient, pre-dating the divergence of the streptophyte and chlorophyte lineages. It also provides a frame of reference for future studies to elucidate the function of trehalose metabolism in plants.
Extensively cross-reactive anti-HIV-1 neutralizing antibodies induced by gp140 immunization
Authors: Zhang Peng Fei , Cham Fatim , Dong Ming , Choudhary Anil , Bouma Peter , Zhang Zhiqiang , Shao Yiming , Feng Yan-Ru , Wang Lemin , Mathy Nathalie , Voss Gerald , Broder Christopher C. , Quinnan Gerald V.
Published: June 2007

An immunization regimen was evaluated in rabbits consisting of the soluble, oligomeric form of envelope glycoprotein of HIV-1, strain R2 (gp140
R2
), or the surface component of the same envelope (Env), gp120
R2
, in the adjuvant AS02A. The gp140
R2
was selected based on its unusual CD4-independent phenotype and the exceptionally broad neutralizing response in the infected donor. The gp140
R2
immunogen induced antibodies that achieved 50% neutralization of 48/48, and 80% neutralization of 43/46 primary strains of diverse HIV-1 subtypes tested. The strains tested included members of standard panels of subtype B and C strains, and other diverse strains known to be neutralization resistant. The gp120
R2
induced antibodies that neutralized 9/48 of the same strains. Neutralization was IgG-mediated and HIV-1-specific. These results demonstrate that induction of truly broad spectrum neutralizing antibodies is an achievable goal in HIV-1 vaccine development.
EXECUTER1- and EXECUTER2-dependent transfer of stress-related signals from the plastid to the nucleus ofArabidopsis thaliana
Authors: Lee Keun Pyo , Kim Chanhong , Landgraf Frank , Apel Klaus
Published: June 2007

Shortly after the release of singlet oxygen (1O2), drastic changes in nuclear gene expression occur in the conditionalflumutant ofArabidopsisthat reveal a rapid transfer of signals from the plastid to the nucleus. In contrast to retrograde control of nuclear gene expression by plastid signals described earlier, the primary effect of1O2generation in theflumutant is not the control of chloroplast biogenesis but the activation of a broad range of signaling pathways known to be involved in biotic and abiotic stress responses. This activity of a plastid-derived signal suggests a new function of the chloroplast, namely that of a sensor of environmental changes that activates a broad range of stress responses. Inactivation of the plastid protein EXECUTER1 attenuates the extent of1O2-induced up-regulation of nuclear gene expression, but it does not fully eliminate these changes. A second related nuclear-encoded protein, dubbed EXECUTER2, has been identified that is also implicated with the signaling of1O2-dependent nuclear gene expression changes. Like EXECUTER1, EXECUTER2 is confined to the plastid. Inactivation of both EXECUTER proteins in theex1/ex2/flutriple mutant is sufficient to suppress the up-regulation of almost all1O2-responsive genes. Retrograde control of1O2-responsive genes requires the concerted action of both EXECUTER proteins within the plastid compartment.
Simple and fast alignment of metabolic pathways by exploiting local diversity
Authors: Wernicke Sebastian , Rasche Florian
Published: June 2007

Motivation: An important tool for analyzing biological networks is the ability to perform homology searches, i.e. given a pattern network one would like to be able to search for occurrences of similar (sub)networks within a set of host networks. In the context of metabolic pathways, Pinter et al. [Bioinformatics, 2005] proposed to solve this computationally hard problem by restricting it to the case where both the pattern and host networks are trees. This restriction, however, severely limits the applicability of their algorithm.

Results: We propose a very fast and simple algorithm for the alignment of metabolic pathways that does not restrict the topology of the host or pattern network in any way; instead, our algorithm exploits a natural property of metabolic networks that we call ‘local diversity property’. Experiments on a test bed of metabolic pathways from the BioCyc database indicate that our algorithm is much faster than the restricted algorithm of Pinter et al.—the metabolic pathways of two organisms can be aligned in mere seconds—and yet has a wider range of applicability and yields new biological insights. Our ideas can likely be extended to work for the alignment of various types of biological networks other than metabolic pathways.

Availability: Our algorithm has been implemented in C++ as a user-friendly metabolic pathway alignment tool called METAPAT. The tool runs under Linux or Windows and can be downloaded at http://theinf1.informatik.uni-jena.de/metapat/;

Contact:  florian.rasche@uni-jena.de

Supplementary information: Supplementary data are available at bioinformatics online.
VISDA: an open-source caBIG™ analytical tool for data clustering and beyond
Authors: Wang Jiajing , Li Huai , Zhu Yitan , Yousef Malik , Nebozhyn Michael , Showe Michael , Showe Louise , Xuan Jianhua , Clarke Robert , Wang Yue
Published: June 2007

Summary: VISDA (Visual Statistical Data Analyzer) is a caBIG™ analytical tool for cluster modeling, visualization and discovery that has met silver-level compatibility under the caBIG initiative. Being statistically principled and visually interfaced, VISDA exploits both hierarchical statistics modeling and human gift for pattern recognition to allow a progressive yet interactive discovery of hidden clusters within high dimensional and complex biomedical datasets. The distinctive features of VISDA are particularly useful for users across the cancer research and broader research communities to analyze complex biological data.

Availability:  http://gforge.nci.nih.gov/projects/visda/

Contact:  yuewang@vt.edu

Supplementary information: Supplementary data are available at Bioinformatics online.
Notch activation stimulates transient and selective binding of Su(H)/CSL to target enhancers
Authors: Krejčí Alena , Bray Sarah
Published: June 2007

The CSL [CBF1/Su(H)/Lag2] proteins [Su(H) in Drosophila] are implicated in repression and activation of Notch target loci. Prevailing models imply a static association of these DNA-binding transcription factors with their target enhancers. Our analysis of Su(H) binding and chromatin-associated features at 11 E(spl) Notch target genes before and after Notch revealed large differences in Su(H) occupancy at target loci that correlated with the presence of polymerase II and other marks of transcriptional activity. Unexpectedly, Su(H) occupancy was significantly and transiently increased following Notch activation, suggesting a more dynamic interaction with targets than hitherto proposed.
Dissociation and Reaggregation of Xenopus laevis Animal Caps
Authors: Sive Hazel L. , Grainger Robert M. , Harland Richard M.
Published: June 2007

INTRODUCTION

Preparations of single cells from Xenopus laevis animal caps are useful for assaying the activity of inducing molecules. These dissociated cells can be exposed to more uniform concentrations of inducing factors than the multilayered intact cap. Single cells derived from caps are also used to analyze the role of cell-to-cell contact. This protocol describes the preparation of cells from Xenopus for use in such assays. Animal caps require divalent cations for their integrity and thus can be dissociated by exposure to medium lacking Ca++ and Mg++ ions. With this treatment, the cells comprising the inner layers of the cap dissociate within ~20 minutes. Cells can be reaggregated after this treatment and should survive well. The outer layer of cells is more recalcitrant to dissociation and requires a more severe treatment.
Ectodermal (Animal Cap) Layer Separations in Xenopus laevis: Figure 1.
Authors: Sive Hazel L. , Grainger Robert M. , Harland Richard M.
Published: June 2007

INTRODUCTION

In Xenopus laevis, the blastula animal cap comprises two morphologically distinct cell layers, an outer monolayer termed the epithelial layer, which consists of tightly adherent pigmented cells, and an inner layer several cells thick termed the sensorial layer, which consists of loosely adherent cells. It is possible to isolate cell layers and to test their developmental potential and response to induction. This protocol describes how to separate the cell layers most easily, that is, by dissecting an intact Xenopus embryo.
Xenopus laevis Einstecks
Authors: Sive Hazel L. , Grainger Robert M. , Harland Richard M.
Published: June 2007

INTRODUCTION

“Einstecks” refers to a procedure for placing a piece of tissue into the blastocoel of an early gastrula, in order to assess the inductive potential of the introduced tissue. The foreign tissue adheres to surrounding tissue and becomes incorporated into the host embryo. This simple transplant procedure, which is described here, has been used to assess which types of axial tissue can be induced by different regions of the mesendoderm or ectoderm, and how forced expression of genes or treatment with various factors can alter this potential.
Transplantation of Xenopus laevis Lens Ectoderm
Authors: Sive Hazel L. , Grainger Robert M. , Harland Richard M.
Published: June 2007

INTRODUCTION

In Xenopus laevis, transplanting a piece of tissue from one site to another (other than into the blastocoel) is a useful way of examining the sequence of inductions required to produce a particular organ. For example, the young primordium of a particular organ can be transplanted from a young individual into an older embryo to determine whether the older embryo still has the capacity to induce the tissue to form the organ. Although this capacity can also be assayed using explants, the complex surroundings of the host embryo cannot be reproduced in an explant. This protocol describes how to transplant a piece of gastrula-stage animal cap ectoderm into the presumptive lens of a neural-plate-stage host embryo. Note that the technique can be adapted for use in other regions of the embryo. Care must be taken to inflict as little damage on the embryo as possible during this procedure. Well-treated embryos recover rapidly, whereas embryos with extensive injuries do not.
Cortical Isolation from Xenopus laevis Oocytes and Eggs: Figure 1.
Authors: Sive Hazel L. , Grainger Robert M. , Harland Richard M.
Published: June 2007

INTRODUCTION

In Xenopus laevis, the cortex is the layer of gelatinous cytoplasm that lies just below the plasma membrane of the egg. Rotation of the cortex relative to the deeper cytoplasm soon after fertilization is intimately linked to normal dorsal axis specification. The cortex can be dissected from the egg to analyze its composition and activity or to clone associated RNAs. This protocol describes a procedure for isolating the vegetal cortex of the fertilized egg.
An Approach for Immunofluorescence of Drosophila S2 Cells: Figure 1.
Authors: Angshuman Sarkar , Cordula Schulz
Published: June 2007

INTRODUCTION

Immunofluorescence is widely used as a technique for visualization of a specific protein in cells or tissue sections. The two major types of immunofluorescence staining methods are (1) direct immunofluorescence staining, in which the primary antibody is labeled with fluorescence dye, and (2) indirect immunofluorescence staining, in which a secondary antibody labeled with fluorochrome is used to recognize a primary antibody. Immunofluorescence staining can be performed on whole tissue, tissue sections, or cells fixed on slides. Despite the availability of various immunofluorescence protocols, it is still a challenge to work with Drosophila S2 cells because of their poor attachment and comparatively low permeability. Here we provide a modified and standardized immunofluorescence protocol specifically for S2 cells.
RNA FISH on Cultured Cells in Interphase: Figure 1.
Authors: Karen Ng , Wutz Anton
Published: June 2007

INTRODUCTION

Fluorescence in situ hybridization (FISH) has become a widely used method in genome and molecular genetic studies. The technique is highly versatile and has been adapted to carry out genome-wide screenings, microarray quantifications, cancer cytogenetics analysis, and RNA expression and localization studies. The study of intracellular RNA localization using RNA FISH provides insights into the in situ physical characteristics of transcription and intracellular RNA transport in individual cells. In our lab, we use RNA FISH to detect the localization of Xist RNA, a nuclear noncoding transcript that coats the entire chromosome from which it is transcribed. The advantage of using RNA FISH in our case is to extract precise molecular information directly in the context of cellular structure. The RNA FISH technique requires the generation of a labeled probe, hybridization of the probe to a fixed sample, and detection of the labeled probe using microscopy.
A Solid-Phase Immunostaining Protocol for High-Resolution Imaging of Delicate Structures in the Drosophila Larval Central Nervous System (CNS)
Authors: Daubert Elizabeth A. , Condron Barry G.
Published: June 2007

INTRODUCTION

This protocol describes a method for mounting and immunostaining Drosophila larval tissue in preparation for high-resolution fluorescent imaging of fine structures in the central nervous system (CNS). Affixing the tissue directly to the coverslip and then moving the coverslip between wash solutions provides a simple solid-phase method of immunostaining that assists in preserving fine structures. This method also easily allows for manipulations and/or viewing of the live sample prior to fixation if desired. Finally, putting the tissue in direct contact with the coverslip places fine structures immediately adjacent to the objective lens. We also briefly describe a method to create three-dimensional (3D) models of confocal Z-stacks in order to better characterize fine structures by measuring their volume and obtaining 3D Cartesian coordinates in space.
Preparation of Zebrafish Embryos for Transmission Electron Microscopy
Authors: Rieger Sandra , Köster Reinhard W.
Published: June 2007

INTRODUCTION

This protocol describes a procedure for the fixation and embedding of zebrafish embryos at organogenesis stages (48-72 hours post-fertilization [hpf]) for transmission electron microscopy (TEM). The lengths of individual steps may be adjusted according to the developmental stage of the specimen.
Cardiac Rehabilitation: A Comprehensive Program for the Management of Heart Failure
Authors: Boudreau Mary , Genovese Janet
Published: June 2007

Heart failure is one of the major health problems found in the United States today. Medical and interventional therapies play an important role in the treatment of this chronic condition, but they create a huge economic burden on the health care system. Nonpharmacologic interventions need further exploration. This article reviews research that examined the relationship between exercise and heart failure. A variety of exercise modalities measured outcomes of functional capacity and quality of life in both supervised and nonsupervised settings. Many investigators found exercise training to be safe and to confer benefits, especially on functional capacity, quality of life, and survival. The most favorable outcomes were observed in supervised settings. Cardiac rehabilitation provides an ideal environment for safe exercise and management of the health care needs of patients with heart failure. The multidisciplinary staff is adept at providing a paced approach to activity based on individualized exercise prescriptions, education, and management of this population's many comorbidities.
Usefulness of RISKO Heart Hazard Appraisal to Quantify CAD Risk Factor Burden on the Preoperative Functioning of Coronary Artery Bypass Graft Surgery Patients
Authors: Barnason Susan , Zimmerman Lani , Nieveen Janet , Schulz Paula , Hertzog Melody , Miller Connie , Rasmussen Doris
Published: June 2007

The preoperative status of coronary artery bypass graft (CABG) surgical patients is often evaluated as a means to assess operative risk for mortality and morbidity and to inform how preoperative status influences or predicts outcomes following CABG surgery. The purpose of this study was to examine the influence of coronary artery disease (CAD) risk factor burden on CABG patients' preoperative functioning (functional status and functional capacity). A convenience sample of 152 subjects, 65 years and older, who had been consecutively enrolled in a larger randomized clinical trial, was evaluated. The RISKO Heart Hazard Appraisal was used to quantify CAD risk factor burden of the subjects. There were significant differences by CAD risk factor burden group, with subjects in the highest CAD risk factor burden group having poorer general health functioning (F2,147=3.45; P<.05) and functional capacity (F2,147=5.43; P<.01). These findings elucidate the potential usefulness of evaluating CABG patients' preoperative CAD risk factor burden status.
Expression of androgen receptor and two androgen‐induced proteins (apolipoprotein D and pepsinogen C) in ductal carcinoma in situ of the breast
Authors: Gonzalez L O , Corte M D , Junquera S , Bongera M , Rodriguez J C , Vizoso F J
Published: June 2007

Aims:  To evaluate the expression of androgen receptors (AR) and two androgen‐induced proteins [apolipoprotein D (ApoD) and pepsinogen C (PepC)] in ductal carcinoma in situ (DCIS) of the breast.

Methods and results:  AR, ApoD and PepC expression was examined in 28 cases of pure DCIS and in 31 cases of DCIS adjacent to invasive carcinoma of the breast using immunohistochemical methods and then correlated with the architectural subtype, the degree of differentiation and the ostrogen receptor (ER)/progesterone receptor (PgR)/HER‐2 status. We found no significant differences between pure DCIS and DCIS adjacent to invasive breast cancer regarding the percentage of positive cases for ApoD (64.3% versus 54.8%), PepC (42.9% versus 48.4%), ER (64.3% versus 58.1%), PgR (60.7% versus 58.1%) and HER‐2 (39.3% versus 67.7%). However, there was a significantly higher percentage of AR+ DCIS among those adjacent to invasive carcinomas of the breast than among pure DCIS lesions (93.5% versus 60.9%) (P = 0.009). AR expression did not correlate with architectural subtype, degree of differentiation, or ER/PgR/HER‐2/ApoD/PepC status, in cases of pure DCIS, nor in DCIS adjacent to invasive carcinoma of the breast.

Conclusions:  AR expression may represent an independent predictive factor in DCIS of the breast.