bluuebunny/crossref_metadata_2025 huggingface dataset:
Surfactant‐Free Spinning of Composite Carbon Nanotube Fibers
Authors: Néri Wilfrid , Maugey Maryse , Miaudet Pierre , Derré Alain , Zakri Cécile , Poulin Philippe
Published: July 2006

Summary: Fibers and yarns are promising forms to use and control the spatial orientation of carbon nanotubes in macroscopic materials. Various approaches have been proposed in the last few years to achieve fibers with a fraction of carbon nanotubes. Among them, coagulation spinning in aqueous media has proven to be a simple and capable method of leading to super‐tough materials. However, all water‐based processes described so far have made use of surfactant‐stabilized carbon nanotubes. In the present work, a method is shown to spin fibers from surfactant‐free nanotube solutions while preserving an all water‐based process. The resultant fibers exhibit mechanical and electrical properties that compare well with those of previously reported fibers spun with surfactants. The fibers exhibit a significant toughness and a high electrical conductivity.

Scanning electron micrograph of the fiber, showing the surface texture.

magnified image

Scanning electron micrograph of the fiber, showing the surface texture.
In vivo quantification of regional myocardial blood flow: Validity of the fast‐exchange approximation for intravascular T1 contrast agent and long inversion time
Authors: Wiart Marlene , Carme Sabin , Maï Wilfried , Larsson Henrik B.W. , Neyran Bruno , Canet‐Soulas Emmanuelle
Published: July 2006

In the present study we investigated the effects of water exchange between intra‐ and extravascular compartments on absolute quantification of regional myocardial blood flow (rMBF) using a saturation‐recovery sequence with a rather long inversion time (TI, 176 ms) and a T1‐shortening intravascular contrast agent (CMD‐A2‐Gd‐DOTA). Data were acquired in normal and ischemically injured pigs, with radiolabeled microsphere flow measurements used as the gold standard. Five water exchange rates (fast, 6 Hz, 3 Hz, 1 Hz, and no exchange) were tested. The results demonstrate that the fast‐exchange approximation may be appropriate for rMBF quantification using the described experimental setting. Relaxation rate change (ΔR1) analysis improved the accuracy of the analysis of rMBF compared to the MR signal. In conclusion, the current protocol could provide sufficient accuracy for estimating rMBF assuming fast exchange and a linear relationship between signal and tissue concentration when quantification of precontrast T1 is not an option. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Melt processing effects on the structure and mechanical properties of PA‐6/clay nanocomposites
Authors: Borse Nitin K. , Kamal Musa R.
Published: July 2006

Polyamide‐6 nanocomposites were prepared using two organoclays, Cloisite 30B and Cloisite 15A, and Cloisite Na+, which is unmodified sodium montmorillonite (Na‐MMT) clay. Nanocomposites were prepared using two twin‐screw extrusion systems: System B employing conventional mixing and residence time conditions, while System A was modified to achieve longer residence time and higher mixing efficiency. The work considers the effects of mixing conditions, residence time, and interactions between the polymer and clay surface on the structure and mechanical properties of polyamide‐6 (PA‐6)/clay nanocomposites. Furthermore, a comparison was made between experimental data and the predictions of composite models usually employed to predict mechanical properties of nanocomposites. The melt processing of Cloisite 30B in System A produced the highest degrees of exfoliation and the largest enhancement of mechanical properties. The aspect ratios of the filler particles in the nanocomposites were estimated from TEM micrographs and from composite models. Yield stress data were employed to calculate the values of parameter B in Pukanszky's equation, which incorporates the effects of the interfacial interaction, interfacial strength, and specific surface area of the filler particles. POLYM. ENG. SCI. 46:1094–1103, 2006. © 2006 Society of Plastics Engineers
Stress dependence of Raman vibrational bands of PbWO4 single crystals
Authors: Zhu W. L. , Wan K. S. , Huang Y. L. , Feng X. Q. , Pezzotti G.
Published: July 2006

A microscopic piezo‐spectroscopic (PS) investigation of the stress dependence of the Raman bands of lead tungstate was conducted, which used a ball‐on‐ring flexure method, aimed at adding controlled biaxial stresses on thin‐plate samples. Spectral shifts varying with applied loads and in‐depth positions were observed for a ‐ and c ‐plane PbWO4 single crystals, confirmed by polarized Raman experiments. Taking account of the laser probe function, theoretical convolutions were performed to determine precisely the PS coefficients, which were determined as Π 11 = Π 22 = –1.29 ± 0.20 cm–1/GPa and Π 33 = –0.87 ± 0.25 cm–1/ GPa for the 902 cm–1 A g species. Accordingly, the residual stresses generated by mechanical treatments were analysed based on the derived coefficients. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
CuInS2 and CuGaS2 thin films grown by modulated flux deposition with various Cu contents
Authors: Guillén C. , Herrero J.
Published: July 2006

Copper indium sulphide and copper gallium sulphide thin films have been prepared using a novel modulated flux deposition process from elemental evaporation sources that were adjusted to give different cation (Cu/In or Cu/Ga) ratios ranging from 0.6 to 1.4. The crystalline structure and optical properties of the samples, as determined by X‐ray diffraction and spectrophotometry, have been analysed as a function of the overall composition. Also, the atomic distribution in the film depth has been obtained by combining X‐ray photoelectron spectroscopy and Ar+ sputter etching. An increase in copper content leads to an increase of the average crystallite size and a decrease of the structural stress, and an increase of the absorption coefficient at low energies. These effects are more pronounced for the copper gallium sulphide than for the copper indium sulphide samples for the preparation conditions used. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hysteresis loops and susceptibility of ferromagnetic or ferrimagnetic bilayer system
Authors: Jiang Wei , Bai Bao‐Dong
Published: July 2006

The hysteresis loops and susceptibility of a ferromagnetic or ferrimagnetic bilayer system consisting of two magnetic monolayers (A and B) with different spins (SA = 1/2 and SB = 3/2) in the presence of the crystal field in the monolayer B have been studied. Within the effective‐field theory based on the differential operator technique, the effects of the external longitudinal magnetic field on the magnetization and susceptibility of the honeycomb lattice are discussed in detail. We show that by choice of the temperature the hysteresis loops can be varied over a very wide range. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermal stability of Fe, Co, Ni metal nanoparticles
Authors: Cao L. F. , Xu G. Y. , Xie D. , Guo M. X. , Luo L. , Li Z. , Wang M. P.
Published: July 2006

The thermal stability of metal nanoparticles is discussed in both melting thermodynamics and interface thermodynamics. Emphases are put on the size and shape dependence of melting temperature, critical size and vacancy‐formation energy of both freestanding and embedded metal nanoparticles. The melting temperature depression and superheating phenomena for reported nanoparticle systems are explained. Critical sizes of Fe, Co, Ni metal nanocrystals that the crystals keep their crystallinity are calculated and the corresponding minimum melting temperatures predicted. The vacancy‐formation energies of Fe, Co, Ni small particles are also calculated as a reference. Theoretical predictions are consistent with experimental results. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamical processes on relaxed excited states in NH4Cl:Tl+ single crystals
Authors: Kawai Taketoshi , Hashimoto Satoshi
Published: July 2006

We have investigated the temperature dependence of temporal behaviors of the AX and AT luminescence bands in NH4Cl:Tl+ single crystals under an ArF excimer laser excitation. The time‐resolved AX luminescence spectra reveal the existence of two luminescence bands which are attributed to the radiative transitions from the relaxed 3T1u and 3A1u states, respectively. The slow decay of the luminescence due to the transition from the 3A1u state in the AX band becomes fast with increasing temperature from 16 K to 27 K. Then, the AT band exhibits a temporal rise reflecting the non‐radiative transition from the AX to AT minima on the adiabatic potential energy surface for the 3A1u state. The temperature dependence of the slow decay time of the AX band is analyzed by using the WKB method considering the non‐radiative transitions from vibrational energy levels in the adiabatic potential well. As a results, the temperature dependence can be fitted by taking the TA phonon energy of the NH4Cl bulk crystal as the separation energy between the vibrational energy levels. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spin‐polarized electronic structure of Mn–IV–V2 chalcopyrites
Authors: Naveh Doron , Kronik Leeor
Published: July 2006

We present ab initio density functional theory calculations for the electronic structure of chalcopyrite Mn–IV–V2, with IV = (Si,Ge) and V = (N,P,As), in their ferromagnetic phase. We find that the P and As containing compounds (some of which been recently synthesized) are normal ferromagnetic metals and are therefore of limited use for spintronic applications. The N containing compounds, however, are predicted to be semiconducting, with a valence band that has a wide energy range with 100% spin polarization. As such, they emerge as interesting candidate materials for spin‐polarized transport. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultrasound imaging of the lower urinary tract after successful tension‐free vaginal tape (TVT) procedure
Authors: Masata J. , Martan A. , Svabik K. , Drahoradova P. , Pavlikova M.
Published: July 2006

Objectives

To evaluate changes in the mobility of the whole urethra, in the proximal urethra (funneling) and in the thickness of the urinary bladder wall, after a successful tension‐free vaginal tape (TVT) procedure.

Methods

This prospective longitudinal study included 52 women with urodynamically confirmed stress urinary incontinence who had undergone a successful TVT procedure. Ultrasound examination was performed before the TVT procedure and at a median of 3 (range, 3–6) months after surgery. For all women, the changes to the urethra and urinary bladder induced by surgery were examined. For three mobility groups (low, intermediate and high urethral mobility before surgery) we compared the changes induced by the operation and the typical position and mobility of the tape.

Results

The position of the urethra at rest was not influenced by surgery. The operation significantly decreased the mobility of all parts of the urethra during Valsalva. The absolute changes of the vector of the urethral movement differed according to the mobility group (average decrease, 6 mm; decrease for women with low, intermediate and high mobility, respectively, 2–3 mm, 4–6 mm and 9 mm). The change in relative mobility was the same in all groups. The operation decreased funneling (width and depth) during maximal Valsalva. After surgery there was an increase in the thickness of the bladder wall (by 0.64 and 0.73 mm, respectively, at the anterior part and trigone).

Conclusions

A successful TVT procedure did not influence the position of the urethra at rest but significantly decreased the mobility of the urethra during Valsalva and also decreased funneling at maximal Valsalva. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Stage‐dependent fetal umbilical blood flow changes induced by laser therapy and amniodrainage in twin‐to‐twin transfusion syndrome
Authors: Becker J. , Hernandez‐Andrade E. , Muñoz‐Abellana B. , Acosta R. , Cabero L. , Gratacós E.
Published: July 2006

Objective

To estimate changes in umbilical blood flow (UBF) and Doppler indices in pregnancies complicated by twin‐to‐twin transfusion syndrome (TTS) treated with either laser therapy or amniodrainage, and to evaluate the influence of the presence of hemodynamic deterioration prior to therapy, as determined by the Quintero stages of severity.

Methods

Forty‐eight cases of TTS were included, and further classified into severity Stages I or II (absence of critically abnormal Dopplers (CAD), n = 22) and Stages III or IV (presence of CAD or hydrops fetalis, n = 26). In Stages I–II, 14 cases were treated with laser and eight with amniodrainage, and in Stages III–IV, 17 were treated with laser and nine with amniodrainage. Differences in the UBF, umbilical artery pulstility index (UA‐PI) and ductus venosus pulsatility index (DV‐PI) were estimated for both groups of severity before and after both treatments. Eleven normal monochorionic pregnancies were evaluated as controls.

Results

In recipients, UBF was significantly higher with respect to controls regardless of the stage, while donors had a significant decrease in UBF, but only in Stages III–IV. After laser treatment no changes were observed in fetuses in Stages I–II. In Stages III–IV, recipients showed a significant reduction in the DV‐PI (mean DV‐PI 1.31 ± 0.18 vs. 1.05 ± 0.22; P = 0.005) whereas donors showed a significant increase in the UBF (mean UBF 134 ± 36 mL/min vs. 195 ± 25 mL/min; P < 0.001) and in the DV‐PI (mean DV‐PI 0.99 ± 0.26 vs. 1.36 ± 0.42; P = 0.002), and a reduction in the UA‐PI (mean UA‐PI 1.86 ± 0.41 vs. 1.58 ± 0.30; P = 0.01). After amniodrainage only donor fetuses in Stages III–IV showed an increase in UA‐PI (mean UA‐PI 1.54 ± 0.35 vs. 1.72 ± 0.40; P = 0.015). No other changes were observed in any of the parameters studied.

Conclusion

Laser therapy induces consistent hemodynamic variations in TTS mainly manifested in Stages III–IV. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Isolation of Δ12 and ω3‐fatty acid desaturase genes from the yeast Kluyveromyces lactis and their heterologous expression to produce linoleic and α‐linolenic acids in Saccharomyces cerevisiae
Authors: Kainou Kumiko , Kamisaka Yasushi , Kimura Kazuyoshi , Uemura Hiroshi
Published: July 2006

Two clones with homology to known fatty acid desaturase genes were isolated from the yeast Kluyveromyces lactis. The first gene, which we designate KlFAD2, consists of 411 amino acids with an overall identity of 73.0% to FAD2 from Saccharomyces kluyveri. It exhibited Δ12 fatty acid desaturase activity when expressed in S. cerevisiae under the control of ADH1 promoter and produced endogenous linoleic acid. The second clone, which we designate KlFAD3, consists of 415 amino acids with an overall identity of 79.3% to FAD3 from S. kluyveri. It exhibited ω3 fatty acid desaturase activity in S. cerevisiae when expressed under the control of ADH1 promoter in the presence of the exogenous substrate linoleic acid and produced α‐linolenic acid. Co‐expression of KlFAD2 and KlFAD3 resulted in the endogenous production of both linoleic and α‐linolenic acids. The yield of α‐linolenic acid reached 0.8% of total fatty acids and its production was not increased by adding exogenous oleic acid; α‐linolenic acid reached 8.7% when exogenous linoleic acid was available. Copyright © 2006 John Wiley & Sons, Ltd.
Biopsychosoziale Anamnese – noch aktuell im Zeitalter der medialen Kommunikation?
Authors: Buddeberg
Published: July 2006

Die Spezialisierung der Medizin führt zu Veränderungen des Informationsaustausches zwischen Arzt und Patient. Neben die direkte, personale Kommunikation tritt immer mehr die indirekte, mediale Kommunikation über interaktive Medien. Für die klinische Untersuchung ist eine je nach Situation und Fragestellung umfassende biopsychosoziale Anamnese nach wie vor eine grundlegende Voraussetzung. Sie umfasst im Idealfall die Geschichte einer Krankheit, eines Erkrankten und seines Leidens. Die inhaltliche Gliederung einer biopsychosozialen Anamnese und Techniken der Gesprächsführung werden in diesem Beitrag im Überblick dargestellt.
Macht der Ultraschall die klinische Untersuchung des Abdomens überflüssig?
Authors: Meyenberger
Published: July 2006

Die klinische Untersuchung als ärztliche Kunst ist zweifellos nach wie vor der Schlüssel zum Patienten, der wichtigste Schritt für ein problemorientiertes und zielgerichtetes Handeln und unabdingbar für einen vernünftigen Einsatz aller heute verfügbaren technischen Mittel.
Reduction of the RACM scheme using Computational Singular Perturbation Analysis
Authors: Løvås T. , Mastorakos E. , Goussis D. A.
Published: July 2006

The modeling of dispersion of reacting pollutants in the atmosphere requires proper description of both the chemistry involved and the transport of pollutants. We present here highly reduced chemical schemes for rural and urban dispersion problems based on the Computational Singular Perturbation (CSP) technique. CSP identifies the steady‐state species for removal, by resolving the “fast” and the “slow” chemistry components. Here, the CSP method is employed for the reduction of the Regional Atmospheric Chemistry Mechanism (RACM), which includes 77 species and 237 reactions. Three cases were tested: (1) a polluted scenario including ground emissions, (2) a relatively cleaner environment with 10% of the emission levels of case 1, and finally (3) rural conditions without any emissions, for which the effects of emissions on the reduction procedure were directly studied. It was found that reduced mechanisms with high degree of reduction, down to a 16 step mechanism, i.e., 56 species in steady state, produced excellent results for most species for all cases. These reduced mechanisms did not change much between urban or rural conditions and the inclusion of emissions did not affect significantly the selection of major species. This indicates the persistence of a well‐defined fast subset of the mechanism, suggesting that the produced reduced mechanisms are valid for a wide range of conditions in the atmosphere.
A global lithospheric magnetic field model with reduced noise level in the Polar Regions
Authors: Lesur Vincent , Maus Stefan
Published: July 2006

Due to persistent ionospheric current systems at high latitudes, satellite magnetic measurements have high noise levels in the Polar regions. Consequently, small‐scale lithospheric features are much more difficult to resolve there than at lower latitudes. Using linear combinations of spherical harmonics (SH), we define localized functions which are band‐limited to a given maximum degree. Thus, a model's SH resolution can be varied over the globe. We produce a lithospheric field model from CHAMP satellite data which resolves features to SH degree 90 at low latitudes, but only to SH degree 60 in the Polar regions. The new model can be downward continued from satellite altitude to the Earth's surface without generating spurious high‐latitude anomalies.
Depletion-induced instability in protein-DNA mixtures: Influence of protein charge and size
Authors: de Vries Renko
Published: July 2006

While there is abundant experimental and theoretical work on polymer-induced DNA condensation, it is still unclear whether globular proteins can condense linear DNA or not. We develop a simple analytical approximation for the depletion attraction between rodlike segments of semiflexible polyelectrolytes such as DNA, induced by nonbinding globular proteins. Monte Carlo simulations show that the approximation works well up to protein volume fractions of at least 20%. From the expression for the depletion attraction we estimate instability thresholds by computing the effective virial coefficient of DNA segments in protein solutions. While globular proteins are found to be much poorer depletion agents than flexible polymers, it should be possible to condense linear DNA with small highly charged globular proteins, at relatively low ionic strengths.
Facilitated diffusion of DNA-binding proteins: Simulation of large systems
Authors: Merlitz Holger , Klenin Konstantin V. , Wu Chen-Xu , Langowski Jörg
Published: July 2006

The recently introduced method of excess collisions to estimate reaction times of protein-DNA systems in the presence of facilitated diffusion (“sliding”) requires a cell of full system size. This bottleneck is avoided with a modification, by which a set of empirical parameters is calibrated using numerical simulations of a small test system. Once this is done, reaction times for systems of arbitrary dimensions are derived by extrapolation. It is shown that at physiological sliding lengths a test system of the order of 100nm radius suffices to extract accurate reaction times for realistic cell dimensions. The achieved speedup, when compared to explicit simulations of the reaction process, is increasing in third order of the extrapolated radius of the cell.
Nanofiber spraying method using a supplementary electrode
Authors: Kim GeunHyung , Kim WanDoo
Published: July 2006

Using a supplementary electrode, electrospun poly(ε-carprolactone) fibers were deposited on various substrates with different electrical properties. The ability to coat the substrates was independent of the surface electric resistance of the substrates. This was due to the charge reduction of the sprayed fibers, which resulted from passing through the supplementary electrode. The sprayed fibers might find applications in smart textiles, advanced coating technology, and as biomedical wound dressings.
Two-photon photoluminescence and excitation spectra of InGaN∕GaN quantum wells
Authors: Li Q. , Xu S. J. , Li G. Q. , Dai D. C. , Che C. M.
Published: July 2006

We report an observation of efficient two-photon photoluminescence (TPL) of InGaN∕GaN multi-quantum-well (MQW) structures using broadband femtosecond near-infrared excitation laser. Near quadratic excitation-intensity dependence and asymmetric collinear interferometric autocorrelation trace of the TPL signal unambiguously verify the nonlinearity of the TPL process. We also measured the excitation spectrum of the TPL signal and found that it can be fitted well with the theoretical two-photon absorption coefficient formula for direct wide gap semiconductors. The decay time of the TPL signal was determined using a time-resolved photoluminescence technique. These results demonstrate the strong nonlinear optical property of InGaN∕GaN MQWs.
Band structure modulation by carrier doping in random-network carbon nanotube transistors
Authors: Nakamura Shuichi , Ohishi Megumi , Shiraishi Masashi , Takenobu Taishi , Iwasa Yoshihiro , Kataura Hiromichi
Published: July 2006

We investigated a role of a Schottky barrier (SB) in carrier doped random-network single-walled carbon nanotube field effect transistors (RN-SWNT-FETs) and the precise estimation of the SB height by a suitable combination of the gate and source-drain voltages. The SB heights were 70meV for hole and 100meV for electron in p- and n-type FETs, respectively. Furthermore, the barrier height was able to be modulated by changing the doping level, which indicates the possibility of controlling the characteristics of RN-SWNT-FETs.
Napier subterranean clover (Trifolium subterraneum L. var. yanninicum)
Authors: Nichols P. G. H. , Barbetti M. J. , Evans P. M. , Craig A. D. , Sandral G. A. , Dear B. S. , Si P. , You M. P.
Published: July 2006

Napier is a late flowering F6-derived crossbred subterranean clover of var. yanninicum [(Katz. et Morley) Zohary and Heller] developed by the collaborating organisations of the National Annual Pasture Legume Improvement Program. It is a replacement for both Larisa and Meteora and has been selected for release on the basis of its greater herbage and seed production and disease resistance to both known races of clover scorch and 2 of the common races of Phytophthora root rot. Napier is recommended for sowing in Victoria, Western Australia, New South Wales, and South Australia. It is best suited to moderately acidic soils prone to water-logging and to loamy and clay soils with good water-holding capacity in areas with a minimum growing season length of 7.5 months, which extends into late November. Napier is well adapted to the permanent pasture systems found in the areas in which it will be grown. Its upright, vigorous growth makes it well suited to grazing by cattle or sheep and to fodder conservation. Napier has been granted Plant Breeders Rights in Australia.
Breaking the one antibody–one target axiom
Authors: Guo Fang , Das Sanjib , Mueller Barbara M. , Barbas Carlos F. , Lerner Richard A. , Sinha Subhash C.
Published: July 2006

Studies at the interface of chemistry and biology have allowed us to develop an immunotherapeutic approach called chemically programmed antibodies (cpAbs), which combines the merits of traditional small-molecule drug design with immunotherapy. In this approach, a catalytic antibody catalyzes the covalent conjugation of a small molecule or peptide to the active site of the antibody, effectively recruiting the binding specificity of the conjugated molecule to the antibody. In essence, this technology provides the tools for breaking the “one antibody–one target axiom” of immunochemistry. Our studies in this area have focused on using the chemistry of the well studied aldolase catalytic antibodies of which mAb 38C2 is a member. Previously, we explored reversible assembly of cpAbs available through diketone chemistry. In this article, we explore a unique proadapter assembly strategy wherein an antibody 38C2-catalyzed transformation unveils a reactive tag that then reacts to form a stable covalent bond with the antibody. An integrin α
v
β
3
antagonist was synthesized with the designed proadapter and studied using human breast cancer cell lines MDA-MB-231 and MDA-MB-435. We demonstrate that this approach allows for (
i
) the effective assembly of cpAbs
in vitro
and
in vivo
, (
ii
) selective retargeting of 38C2 to integrin α
v
β
3
expressing breast cancer cell lines, (
iii
) intracellular delivery of cpAbs into cells, (
iv
) dramatically increased circulatory half-life, and (
v
) substantial enhancement of the therapeutic effect over the peptidomimetic itself in animal models of breast cancer metastasis. We believe that this technology possesses potential for the treatment and diagnosis of disease.
Some rational maps whose Julia sets are not locally connected
Authors: Roesch P.
Published: July 2006

We describe examples of rational maps which are not topologically conjugate to a polynomial and whose Julia sets are connected but not locally connected.
Capping Protein and the Arp2/3 Complex Regulate Nonbundle Actin Filament Assembly to Indirectly Control Actin Bundle Positioning duringDrosophila melanogasterBristle Development
Authors: Frank Deborah J. , Hopmann Roberta , Lenartowska Marta , Miller Kathryn G.
Published: July 2006

Drosophila melanogaster bristle development is dependent on actin assembly, and prominent actin bundles form against the elongating cell membrane, giving the adult bristle its characteristic grooved pattern. Previous work has demonstrated that several actin-regulating proteins are required to generate normal actin bundles. Here we have addressed how two actin regulators, capping protein, a barbed end binding protein, and the Arp2/3 complex, a potent actin assembly nucleator, function to generate properly organized bundles. As predicted from studies in motile cells, we find that capping protein and the Arp2/3 complex act antagonistically to one another during bristle development. However, these proteins do not primarily act directly on bundles, but rather on a dynamic population of actin filaments that are not part of the bundles. These nonbundle filaments, termed snarls, play an important role in determining the number and spacing of the actin bundles. Reduction of capping protein leads to an increase in snarls, which prevents actin bundles from properly attaching to the membrane. Conversely, loss of an Arp2/3 complex component leads to a loss of snarls and accumulation of excess membrane-attached bundles. These results indicate that in nonmotile cells dynamic actin filaments can function to regulate the positioning of stable actin structures. In addition, our results suggest that the Arpc1 subunit may have an additional function, independent of the rest of the Arp2/3 complex.
Searching RNA motifs and their intermolecular contacts with constraint networks
Authors: Thébault P. , de Givry S. , Schiex T. , Gaspin C.
Published: July 2006

Motivation: Searching RNA gene occurrences in genomic sequences is a task whose importance has been renewed by the recent discovery of numerous functional RNA, often interacting with other ligands. Even if several programs exist for RNA motif search, none exists that can represent and solve the problem of searching for occurrences of RNA motifs in interaction with other molecules.

Results: We present a constraint network formulation of this problem. RNA are represented as structured motifs that can occur on more than one sequence and which are related together by possible hybridization. The implemented tool MilPat is used to search for several sRNA families in genomic sequences. Results show that MilPat allows to efficiently search for interacting motifs in large genomic sequences and offers a simple and extensible framework to solve such problems. New and known sRNA are identified as H/ACA candidates in Methanocaldococcus jannaschii.

Availability:  

Contact:  milpat@toulouse.inra.fr
ZooDDD: a cross-species database for digital differential display analysis
Authors: Chen Yun-Ching , Hsiao Chung-Der , Lin Wen-Dar , Hu Chung-Ming , Hwang Pung-Pung , Ho Jan-Ming
Published: July 2006

Summary: In this article, we combined EST information from the UniGene database and orthologous relationships from the Ensembl database to construct a ZooDDD database. The primary function of ZooDDD is to mine evolutionary conserved, highly expressed, tissue-specific orthologues in model animals. The candidate genes of interest derived from the ZooDDD database will provide biologists with a good step for comparing the expression, functions and evolution of animal genomes.

Availability:  

Contact:  cyc@iis.sinica.edu.tw, pphwang@gate.sinica.edu.tw, hoho@iis.sinica.edu.tw
Extracellular Matrix Metalloprotease Inducer Stimulates Fibroblast‐Mediated Tumor Growth In Vivo
Authors: Rosenthal Eben L. , Vidrine D Macy , Zhang Wenyue
Published: July 2006

Hypothesis: Extracellular matrix metalloprotease inducer (EMMPRIN) is a molecule expressed on the cell surface of tumor cells that has been shown to induce both tumor cells and fibroblasts to express matrix metalloproteases in vitro. We hypothesize that fibroblasts are stimulated by EMMPRIN to create a microenvironment favorable to tumor growth.

Study Design: Case series review of laryngeal cancer and assessment of tumor cell lines in vivo.

Methods: EMMPRIN immunoreactivity in 33 pathologic specimens from patients with supraglottic laryngeal cancer was correlated with clinicopathologic features and survival. The CAL 27 cell line was transfected with EMMPRIN (CAL 27E) or a control vector (CAL 27). Cells were xenografted into the flank of severe combined immunodeficient (SCID) mice with or without a co‐injection of normal dermal fibroblasts (NDFs).

Results: Immunohistochemical detection of EMMPRIN in laryngeal cancer specimens demonstrated expression in all the tumors but not in adjacent, histologically normal mucosa. EMMPRIN membrane immunoreactivity (transmembrane EMMPRIN score) was associated with nodal positivity (P = .07), and it was associated with poorer survival (hazard ratio = 2.4, 95% confidence interval 0.88, 6.55). As a categoric variable, higher EMMPRIN expression positively correlates with higher mortality. To determine whether EMMPRIN mediates tumor growth in vivo through fibroblast stimulation, EMMPRIN‐expressing CAL 27 (CAL 27E) xenografted (n = 20) onto the flank of SCID mice developed larger tumors than CAL 27 control vector transfected cells alone (n = 20), but they were not significantly larger (P = .17). However, when CAL 27E cells were co‐injected with NDFs, there was a statistically significant increase in tumor growth compared with the CAL 27 cells co‐injected with NDFs (n = 10, P = .0038).

Conclusions: As a cell surface expressed protein that promotes tumor growth and high expression in head and neck squamous cell carcinoma but not in normal tissue, EMMPRIN may be a good target for directed molecular therapy.
A Comparative Study of 200 Fine Needle Aspiration Biopsies Performed by Clinicians and Cytopathologists
Authors: Wu Maoxin , Burstein David E. , Yuan Songyang , Nurse Leslie A. , Szporn Arnold H. , Zhang David , Genden Eric
Published: July 2006

Fine needle aspiration (FNA) biopsy is a useful tool in the diagnosis and management of suspicious masses. Most FNA biopsies of palpable masses can be performed without radioguidance by either clinicians or cytopathologists; however, it is unclear if there is a difference in the diagnostic yield of the procedure based on who performs the FNA. We reviewed the FNA biopsy results of 200 patients presenting with head and neck masses to a tertiary care center from 2003 to 2004. One hundred FNA biopsies were performed by clinicians and 100 performed by cytopathologists. Seventy‐one underwent subsequent surgical biopsy or definitive surgery. Results of the FNA biopsies performed by the clinicians and the cytopathologists were compared based on the percentages of FNAs that were diagnostic, suspicious/suggestive, and nondiagnostic. Additionally, the pathology results of the 71 surgical biopsies or resections were compared with the preoperative FNA results. Of the 100 FNA biopsies performed by cytopathologists, 83% were diagnostic, 10% were suspicious/suggestive, and 7% were nondiagnostic. Of the 100 FNA biopsies performed by clinicians, 24% were diagnostic, 43% were suspicious/suggestive, and 33% were nondiagnostic. Cytopathologists achieved significantly better results (P < .0001, two‐tailed t‐test). Of the 71 cases with surgical follow up (50 by cytopathologists and 21 by clinicians), 94% of cases performed by cytopathologists and 67% of those performed by clinicians show agreement with final surgical pathology results. Overall, the FNAs performed by cytopathologists show significantly better diagnostic accuracy (P = .0002134, two‐tailed t‐test). FNA provides valuable information in the workup of suspicious head and neck masses. Cytopathologists may achieve significantly better results.
Congenital Stapes Ankylosis: Study of 28 Cases and Surgical Results
Authors: Albert Sebastien , Roger Gilles , Rouillon Isabelle , Chauvin Pierre , Denoyelle Francoise , Derbez Remi , Delattre Jerome , Triglia Jean‐Michel , Garabedian Erea‐Noel
Published: July 2006

Objective: The objective of this study was to analyze functional results after stapes surgery in patients with congenital nonprogressive conductive deafness resulting from an isolated fixation of the stapes according to age and surgical procedure.

Study Design: The authors conducted a retrospective case series from March 1993 to December 2003 in patients from two tertiary referral centers.

Methods: Twenty‐eight patients were operated on by stapedotomy or partial stapedectomy using Teflon stapes prostheses. The median age at surgery was 14.2 years (range, 8.3–29.1 years). Main outcome measures were clinical and audiometric evaluation before and after surgery. Mean air conduction (MAC) and bone conduction (MBC) thresholds were recorded at 0.5, 1, 2, and 4 kHz. The evaluation of functional outcome was based on the MAC gain, the MBC comparison, and the mean postoperative and residual air–bone gaps.

Results: The median preoperative MAC was 50 dB (range, 19.0–65.0 dB) with a 35.0 dB median dB air–bone gap. With a mean follow up of 19 months, postoperative hearing improvement was statistically significant: median gain of 32.5 dB (P < .001) and median residual air–bone gap of 3.5 dB. The MBC was also statistically improved with median pre‐ and postoperative MBC of 11.5 and 6.5 dB, respectively (P < .001). Results were not dependent on the age group or type of surgery (stapedotomy or partial stapedectomy). No perceptive hearing loss was observed despite one gusher case.

Conclusion: Surgical treatment of isolated congenital stapes ankylosis allows good functional results regardless of age or type of surgery.
Bacillus massiliensis sp. nov., isolated from cerebrospinal fluid
Authors: Glazunova Olga O. , Raoult Didier , Roux Véronique
Published: July 2006

An unidentified Gram-negative-staining, aerobic, rod-shaped, spore-forming bacterium was isolated from a sample of cerebrospinal fluid. Based on comparative analysis of 16S rRNA gene sequences and phenotypic characteristics, the novel isolate was included in the Bacillus sphaericus-like group. The isolate was closely related to Bacillus odysseyi and Bacillus silvestris, with 96.2 and 94.4 % 16S rRNA gene sequence similarity, respectively. The major fatty acid was iso-C15 : 0 (48 %). The name Bacillus massiliensis sp. nov. is proposed for the novel isolate, with strain 4400831T (=CIP 108446T=CCUG 49529T) as the type strain.
Thermomonas koreensis sp. nov., a mesophilic bacterium isolated from a ginseng field
Authors: Kim Myung Kyum , Im Wan-Taek , In Jun-Gyo , Kim Sung-Hoon , Yang Deok-Chun
Published: July 2006

A Gram-negative, non-spore-forming, rod-shaped, motile bacterium, strain Ko06T, was isolated from soil from a ginseng field in South Korea and was characterized in order to determine its taxonomic position. 16S rRNA gene sequence analysis revealed that strain Ko06T belongs to the Gammaproteobacteria, and the highest levels of sequence similarity were with Thermomonas brevis LMG 21746T (98.4 %), Thermomonas fusca LMG 21737T (97.7 %), Thermomonas haemolytica A50-7-3T (96.5 %) and Thermomonas hydrothermalis SGM-6T (95.8 %). Chemotaxonomic data revealed that strain Ko06T possesses ubiquinone Q-8 and that the predominant fatty acids are C15 : 0 iso, C11 : 0 iso and C11 : 0 iso 3-OH, all of which corroborated assignment of the strain to the genus Thermomonas. The results of DNA–DNA hybridization and physiological and biochemical tests clearly demonstrated that strain Ko06T represents a distinct species. On the basis of these data, strain Ko06T (=KCTC 12540T=NBRC 101155T) should be classified as the type strain of a novel Thermomonas species, for which the name Thermomonas koreensis sp. nov. is proposed.
Optimizing Electrotransfection of Mammalian Cells In Vitro
Authors: Li Shulin
Published: July 2006

INTRODUCTION

This protocol describes transfection of plasmid DNA into mammalian cell lines using electroporation, a process whereby external application of electric pulses induce cell membrane permeability. A number of factors can affect electrotransfection efficiency. In general, cells in suspension and small volume cells are difficult to transfect, whereas adherent cells and large volume cells are relatively easy. Regardless of cell size or phenotype, transfection efficiency increases with a high concentration of cells in a small volume. The use of plasmid DNA larger than 13 kb reduces transfection efficiency. One important variable is the choice of electroporation buffer--the appropriate buffer can increase cell transfection efficiency 50-98%. Generally, buffers with low ionic constants enhance transfection efficiency.
Secondary structure determines protein topology
Authors: Fleming Patrick J. , Gong Haipeng , Rose George D.
Published: July 2006

Using a test set of 13 small, compact proteins, we demonstrate that a remarkably simple protocol can capture native topology from secondary structure information alone, in the absence of long‐range interactions. It has been a long‐standing open question whether such information is sufficient to determine a protein's fold. Indeed, even the far simpler problem of reconstructing the three‐dimensional structure of a protein from its exact backbone torsion angles has remained a difficult challenge owing to the small, but cumulative, deviations from ideality in backbone planarity, which, if ignored, cause large errors in structure. As a familiar example, a small change in an elbow angle causes a large displacement at the end of your arm; the longer the arm, the larger the displacement. Here, correct secondary structure assignments (α‐helix, β‐strand, β‐turn, polyproline II, coil) were used to constrain polypeptide backbone chains devoid of side chains, and the most stable folded conformations were determined, using Monte Carlo simulation. Just three terms were used to assess stability: molecular compaction, steric exclusion, and hydrogen bonding. For nine of the 13 proteins, this protocol restricts the main chain to a surprisingly small number of energetically favorable topologies, with the native one prominent among them.
Mentoring adolescent foster youth: promoting resilience during developmental transitions
Authors: Osterling Kathy Lemon , Hines Alice M.
Published: July 2006

The current exploratory study used quantitative and qualitative data from an evaluation of the ‘Advocates to Successful Transition to Independence’ programme, a mentoring programme designed to train mentors to assist older adolescent foster youth in acquiring skills and resources needed for successful transition out of foster care and into adulthood. The study was conducted in two phases over 2 years. Quantitative methods were used to describe characteristics of the older adolescent foster youth and advocates, and qualitative methods were used to describe the experiences of youth and advocates in the programme. Results suggest that the use of a mentoring programme for older adolescent foster youth represents a particularly beneficial prevention strategy that may help prevent negative outcomes as youth emancipate from the foster care system and transition into young adulthood. Implications and recommendations for developing mentoring programmes for transition‐aged youth are presented.
Short‐term variation in the isotopic composition of organic matter allocated from the leaves to the stem of Pinus sylvestris: effects of photosynthetic and postphotosynthetic carbon isotope fractionation
Authors: BRANDES ELKE , KODAMA NAOMI , WHITTAKER KATHERINE , WESTON CHRISTOPHER , RENNENBERG HEINZ , KEITEL CLAUDIA , ADAMS MARK A. , GESSLER ARTHUR
Published: July 2006

We aimed to quantify the separate effects of photosynthetic and postphotosynthetic carbon isotope discrimination on δ13C of the fast‐turn‐over carbon pool (water soluble organic carbon and CO2 emitted from heterotrophic tissues), including their diel variation, along the pathway of carbon transport from the foliage to the base of the stem.

For that purpose, we determined δ13C in total and water‐soluble organic matter of the foliage plus δ13C and δ18O in phloem organic matter of twigs and at three heights along the stem of Pinus sylvestris over a nine‐day period, including four measurements per day. These data were related to meteorological and photosynthesis parameters and to the δ13C of stem‐emitted CO2.

In the canopy (foliage and twigs), the δ13C of soluble organic matter varied diurnally with amplitudes of up to 1.9‰. The greatest 13C enrichment was recorded during the night/early morning, indicating a strong influence of starch storage and remobilization on the carbon isotope signatures of sugars exported from the leaves. 13C enrichment of soluble organic matter from the leaves to the twig phloem and further on to the phloem of the stem was supposed to be a result of carbon isotope fractionation associated with metabolic processes in the source and sink tissues. CO2 emitted from the stem was enriched by 2.3–5.2‰ compared with phloem organic matter. When day‐to‐day variation was addressed, water‐soluble leaf δ13C and twig phloem δ18O were strongly influenced by ci/ca and stomatal conductance (Gs), respectively.

These results show that both photosynthetic and postphotosynthetic carbon isotope fractionation influence δ13C of organic matter over time, and over the length of the basipetal transport pathway. Clearly, these influences on the δ13C of respired CO2 must be considered when using the latter for partitioning of ecosystem CO2 fluxes or when the assessment of δ13C in organic matter is applied to estimate environmental effects in ci/ca.
Reconsidering null models of diversity: Do geometric constraints on species ranges necessarily cause a mid‐domain effect?
Authors: Sandel Brody S. , McKone Mark J.
Published: July 2006

Recent null models that place species ranges randomly within a bounded domain have produced controversial results. Many such geometric constraint models predict a peak in species richness in the centre of domains in the absence of underlying environmental gradients or interspecific interactions. We used two‐dimensional simulation models to explore different ways that species ranges could interact with the domain boundary. In the rejection model, a randomly generated range that overlaps a domain boundary is removed from the simulation. In the reshaping model, a range that overlaps the domain boundary is reshaped so that the entire range is placed within the domain. The truncation model allows potential ranges to extend across the boundary, but only that portion of the range within the domain is included in the realized range. Both rejection and reshaping models produced a drop in species richness near domain boundaries, though the effect was less pronounced in the reshaping model. Our truncation model did not produce any spatial pattern in species richness. Thus the random placement of species ranges within a bounded domain does not necessarily lead to a mid‐domain effect.

 Range truncation is consistent with bioclimate envelope models, which can successfully predict a species range in response to the availability of appropriate climate conditions. We argue that such flexible range sizes are more realistic than the assumption that range size is an unvarying characteristic of a species. Other range characteristics, including size and shape, can change near domain boundaries in the null models, including the truncation model. A broader consideration of range characteristics near domain boundaries could be productive.
Psychological stress affects response to sublingual immunotherapy in asthmatic children allergic to house dust mite
Authors: Ippoliti Flora , Santis Wladimiro De , Volterrani Anna , Canitano Nicoletta , Frattolillo Daniele , Lucarelli Sandra , Frediani Simone , Frediani Tullio
Published: July 2006

While the clinical and immunologic efficacy of sublingual immunotherapy (SLIT) in allergic diseases has been extensively demonstrated, some patients display a poor clinical response. Psychological stress has been shown to play a role in atopy and also to affect response to immunomodulating therapies such as vaccination with microbial antigens. This study addresses the possibility of response to SLIT being affected by psychological stress. Forty children with mild asthma caused by allergy to Dermatophagoides pteronyssinus and farinae were subjected to SLIT and then divided after 6 months into two groups based on the results of the stress integrated measure (SIM) test: group 1 (24 stressed patients, mean SIM value of 60.1) and group 2 (16 non‐stressed patients, mean SIM value of 7.6). There was also a higher prevalence of psychosocial stressing factors (divorced/absent parents, low income households, non‐working parents) among stressed patients. The symptom score, peak expiratory flow (PEF), forced expiratory volume in 1 s (FEV1) and serum eosinophie cationic protein (ECP) concentration were evaluated at both times. The serum concentration of neuroendocrine parameters [prolactin, cortisol, adrenocorticotropic hormone (ACTH)] was also measured after 6 months of therapy. While all the clinical parameters and ECP concentration improved after SLIT, symptom score, PEF and ECP showed a significantly greater improvement in non‐stressed patients. The concentration of neuroendocrine parameters was significantly increased in stressed patients. Our findings show that psychological stress can affect response to SLIT also in allergic subjects and are consistent with data recently reported showing a correlation between stress and poor response to antimicrobial vaccines. Our data also suggest that stress evaluation may become a useful prognostic factor in immunotherapy.