bluuebunny/crossref_metadata_2025 huggingface dataset:
Metabolomic investigation of CLN6 neuronal ceroid lipofuscinosis in affected South Hampshire sheep
Authors: Pears Michael R. , Salek Reza M. , Palmer David N. , Kay Graham W. , Mortishire‐Smith Russell J. , Griffin Julian L.
Published: May 2007

The neuronal ceroid lipofuscinoses (NCLs; Batten disease) are a group of fatal inherited neurodegenerative diseases in humans and animals distinguished by a common clinical pathology, characteristic storage body accumulation in cells, and gross brain atrophy. An 1H NMR spectroscopy‐ and GC‐MS‐based metabolomic investigation of changes in the cerebellum, frontal and occipital lobes, and cerebrospinal fluid (CSF) of CLN6 NCL affected South Hampshire sheep charted changes from the preclinical state to advanced disease. Glutamine and succinate concentrations increased in all brain regions in affected sheep relative to controls, whereas concentrations of aspartate, acetate, glutamate, N‐acetyl aspartate (NAA), and γ‐aminobutyric acid (GABA) decreased. Changes in the concentrations of inositols, NAA, and GABA were consistent with glial cell activation and neurodegeneration beginning in the frontal and occipital lobes, in agreement with previous histopathological data. Further metabolic deficits were defined in all regions at earlier time points, including the cerebellum, where very little neurological degeneration has been reported. Biochemical abnormalities in the CSF of affected sheep at 18–31 months include relative increases in lactate, acetate, tyrosine, and creatine/creatinine concentrations and decreases in myo‐ and scyllo‐inositol and citrate concentrations. The changes detected in the CSF and brain tissue mirrored those previously apparent in NCL mouse models, suggesting that they are common to all NCLs. However, the changes in glutamate and glutamine concentrations in CSF occurred after clinical disease, indicating that any changes in glutamate/glutamine cycling occur as a consequence of the primary deficits associated with the NCLs. © 2007 Wiley‐Liss, Inc.
Immunohistochemical distribution of glucose‐dependent insulinotropic polypeptide in the adult rat brain
Authors: Nyberg Jenny , Jacobsson Calle , Anderson Michelle F. , Eriksson Peter S.
Published: May 2007

We have previously demonstrated that glucose‐dependent insulinotropic polypeptide (GIP; gastric inhibitory polypeptide) is present in the adult rat hippocampus. This finding leads to the conclusion that all members of the secretin‐glucagon family of gastrointestinal regulatory polypeptides can be found in the brain. To investigate the localization of GIP‐producing cells, we used immunohistochemistry on sections of the adult rat brain. High levels of GIP immunoreactivity were observed in the olfactory bulb, hippocampus, and Purkinje cells in the cerebellum. Moreover, a moderate but distinct GIP immunoreactivity was observed in the cerebral cortex, amygdala, substantia nigra, and lateral septal nucleus as well as in several nuclei in the thalamus, hypothalamus, and brainstem. GIP immunoreactivity was frequently found to colocalize with the neuronal marker NeuN but never with the glial marker glial fibrillary acidic protein. Thus, GIP appears to be mainly neuronal to its distribution. This widespread distribution of GIP‐immunoreactive cells suggests the involvement of GIP in various neuronal functions and suggests that GIP may act as a neurotransmitter or neuromodulator. This is the first characterization of the anatomical distribution of GIP‐immunoreactive cells in the rat brain providing an anatomical framework for future investigations regarding the functions of GIP in the central nervous system. © 2007 Wiley‐Liss, Inc.
Amyloid beta protein‐related death‐inducing protein induces G2/M arrest: Implications for neurodegeneration in Alzheimer's disease
Authors: Lakshmana Madepalli K. , Hara Hideo , Tabira Takeshi
Published: May 2007

Amyloid beta protein (Aβ)‐related death‐inducing protein (AB‐DIP) is a novel Aβ binding protein expressed ubiquitously. Here we demonstrate that overexpression of AB‐DIP in SH‐SY5Y neuroblastoma cells causes G2/M arrest. By deletion mutant analysis, we have identified the minimal region within AB‐DIP required for G2/M arrest. We have also shown that microtubule‐interfering agents (MIAs) such as nocodazole, vinblastine, paclitaxel, and vincristine, known to arrest cells at G2/M, also phosphorylate AB‐DIP. However, etoposide, which causes genotoxic stress; tunicamycin, an ER stress inducer; and rotenone, which causes mitochondrial damage, fail to phosphorylate AB‐DIP, implying that phosphorylation of AB‐DIP is specific to microtubule‐disruption‐induced G2/M arrest. By using different classes of kinase inhibitors, we also demonstrate that a putative tyrosine kinase phosphorylates AB‐DIP. Mono‐ or multisite mutations of tyrosine or serine/threonine residues confirmed that mutation of tyrosine residues but not serine/threonine residues greatly reduces nocodazole‐induced phosphorylation of AB‐DIP. Furthermore, phosphorylation of AB‐DIP can be induced in MCF‐7 cells that lack functional p53, suggesting that AB‐DIP phosphorylation is independent of p53. Mounting experimental evidence continues to support the role of cell cycle abnormalities in the pathogenesis of Alzheimer's disease, and our results suggest that AB‐DIP might provide a mechanistic link between microtubule disruption, mitotic abnormalities, neuronal dysfunction, and death. Therefore, interfering with AB‐DIP may have therapeutic applications in conditions such as Alzheimer's disease, in which microtubule disruption and mitotic abnormalities have been suggested to play a pathological role. © 2007 Wiley‐Liss, Inc.
Chemokine ligand 2 (CCL2) induces migration and differentiation of subventricular zone cells after stroke
Authors: Liu Xian Shuang , Zhang Zheng Gang , Zhang Rui Lan , Gregg Sara R. , Wang Lei , Yier Toh , Chopp Michael
Published: May 2007

Ischemic stroke stimulates neurogenesis in the adult rodent brain. The molecules that mediate stroke‐induced neurogenesis have not been fully investigated. Using a microarray containing 113 known genes associated with angiogenesis, we analyzed transcriptional profiles in subventricular zone (SVZ) tissue and in cultured neural progenitor cells isolated from the SVZ of adult mice subjected to middle cerebral artery occlusion (MCAo). Among the genes most robustly up‐regulated by MCAo were chemokine ligand 2 (CCL2) and chemokine ligand 10 (CXCL10). Consistent with the mRNA data, immunofluorescent staining revealed that MCAo substantially increased the number of CCL2‐positive cells in the ipsilateral SVZ and that CCL2‐positive cells were positive for both glial fibrillary acidic protein (GFAP) and nestin. In vitro studies showed that incubation of neural progenitor cells with recombinant human CCL2 substantially increased the number of Tuj1‐positive cells dose dependently compared with the number in the control group, indicating that CCL2 promotes neuronal differentiation. Blockage of CCL2 with a neutralized antibody against CCL2 abolished the effects of CCL2 on neural progenitor cell migration and differentiation. Treatment of neural progenitor cells with CCL2 did not alter the number of BrdU cells and the number of apoptotic cells compared with those in the control group, suggesting that CCL2 does not affect neural progenitor cell proliferation and cell survival. These data demonstrate that in addition to its role in cell motility, CCL2 plays an important role in neuronal differentiation. © 2007 Wiley‐Liss, Inc.
Effects of OP‐1 and PTH in a new experimental model for the study of metaphyseal bone healing
Authors: Tsiridis Eleftherios , Morgan Elise F. , Bancroft Jared M. , Song Mike , Kain Michael , Gerstenfeld Louis , Einhorn Thomas A. , Bouxsein Mary L. , Tornetta Paul
Published: May 2007

The purpose of this study was to establish a reliable model of metaphyseal bone healing and to use this model to investigate the effect of recombinant human osteogenic protein 1 (rhOP‐1; BMP‐7) and parathyroid hormone fragment (PTH 1–34) on healing. A wedge‐shaped osteotomy was created in the distal tibia of 16‐week‐old female New Zealand White rabbits (n = 20) and was bridged with a custom‐made external fixator. Five experimental groups of four animals each were investigated. In groups 1–4 the osteotomy gap was filled with tricalcium phosphate (TCP), and the gap was left unfilled in group 5 (“normal healing”). In group 1, 200 µg OP‐1 was mixed in with the TCP. Groups 2 and 3 received daily subcutaneous injections of 10 and 40 µg/kg PTH, respectively, beginning on postoperative day 1. Radiographs were taken weekly. Following sacrifice on postoperative day 28, peripheral quantitative computed tomography (pQCT), histology, and mechanical testing (axial compression and torsion) were performed. Only one animal failed to complete the full 4‐week time course, and no infections were encountered. Bone healing occurred in all animals. OP‐1 stimulated bone formation locally, while the lower dose of PTH enhanced bone formation systemically (p < 0.05). Tibiae treated with OP‐1 exhibited higher torsional strength (p = 0.04) than those in the normal healing group. These results indicate that a reliable and reproducible surgical model of metaphyseal healing has been established. In addition, differences in systemic versus local effects of PTH and OP‐1 in accelerating metaphyseal fracture healing were found. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1193–1203, 2007
Prediction and understanding system peaks in capillary zone electrophoresis
Authors: Gaš Bohuslav , Hruška Vlastimil , Dittmann Monika , Bek Fritz , Witt Klaus
Published: May 2007

Introduction of a sample into the separation column (microchip channel) in capillary zone electrophoresis (microchip electrophoresis) will cause a disturbance in the originally uniform composition of the background electrolyte. The disturbance, a system zone, can move in some electrolyte systems along the separation channel and, on reaching the position of the detector, cause a system peak. As shown by the linear theory of electromigration based on linearized continuity equations formulated in matrix form, the mobility of the system zone – the system eigenmobility – can be obtained as the eigenvalue of the matrix. Progress in the theory of electromigration allows us to predict the existence and mobilities of the system zones, even in very complex electrolyte systems consisting of several multivalent weak electrolytes, or in micellar systems (systems with SDS micelles) used for protein sizing in microchips. The theory is implemented in PeakMaster software, which is available as freeware (www.natur.cuni.cz/gas). The linearized theory also predicts background electrolytes having no stationary injection zone (water zone, water gap, water dip, EO zone) or unstable electrolyte systems exhibiting oscillations and creating periodic structures. The oscillating systems have complex system eigenmobilities (eigenvalues of the matrix are complex). This paper reviews the theoretical background of the system peaks (system eigenpeaks) and gives practical hints for their prediction and for preparing background electrolytes not perturbed by the occurrence of system peaks and by excessive peak broadening.
Surface modified polypropylene pipette tips packed with a monolithic plug of adsorbent for high‐throughput sample preparation
Authors: Altun Zeki , Hjelmström Anette , Abdel‐Rehim Mohamed , Blomberg Lars G.
Published: May 2007

UV‐initiated poly(butyl methacrylate‐ethylene glycol dimethacrylate) porous polymer monoliths were prepared in situ in polypropylene‐based pipette tips for high‐throughput sample preparation. Prior to the in situ polymerization, the surface of the PP tips was modified. In this work, two different surface modification approaches were tested for this purpose. First the photoinitiator benzophenone was used to generate radicals at the surface of PP by hydrogen abstraction. In the second modification approach, a thin layer of a polymer was directly grafted to the surface. The effect of surface modification was measured by contact angle measurements of a drop of water at the surface. As a result of the surface modification, scan electron microscopy images indicate a covalent attachment of the monolith to the wall of the pipette tip. Pipette tips modified with 5% BP in methanol and packed with a plug of monolith were further evaluated for high‐throughput sample preparation. Using a liquid handling system, the extraction performance of packed pipette tips was tested for the analysis of ropivacaine in plasma samples. The recovery and reproducibility results were in accordance with internationally accepted criteria for qualitative and quantitative analysis of the test substance, ropivacaine.
Functionalized HMS mesoporous silica as solid phase extractant for Pb(II) prior to its determination by flame atomic absorption spectrometry
Authors: Pérez‐Quintanilla Damián , Sánchez Alfredo , del Hierro Isabel , Fajardo Mariano , Sierra Isabel
Published: May 2007

In this work, a mesoporous silica has been chemically modified with 5‐mercapto‐1‐methyl‐1‐H‐tetrazol using the homogeneous route (MTTZ‐HMS). This synthetic route involved the reaction of 5‐mercapto‐1‐methyl‐1‐H‐tetrazol with 3‐chloropropyltriethoxysilane, prior to immobilization on the support. The resulting material has been characterized and employed as solid phase extractant for Pb(II). The effect of several variables (stirring time, pH, temperature, metal concentration, presence of other metals) has been studied using batch and column techniques. In batch experiments, 15 min stirring time, 55°C and pH 8 were the optimal conditions for Pb(II) adsorption. In column experiments, sorption was quantitative for 1000 mL of 2.41×10–4 mM of Pb(II) solution and adsorbed ions were eluted out by 5 mL of 1 M HCl (preconcentration factor of 200). Spiked tap water was used for the preconcentration and determination of Pb(II) by flame atomic absorption spectrometry, and a 100% recovery was obtained. The LOD and LOQ values of the proposed method were found to be 3.52×10–3 and 4.20×10–3 mM, respectively. The RSD for three preconcentration experiments was found to be ⪇2%. The linear working range for measurements was between 2×10–3 and 0.14 mM (y = 0.0136x + 0.0007, R2 = 0.9999).
Acceleration of absolute negative mobility
Authors: Regtmeier Jan , Grauwin Sebastian , Eichhorn Ralf , Reimann Peter , Anselmetti Dario , Ros Alexandra
Published: May 2007

Recently, the counter intuitive migration phenomenon of absolute negative mobility (ANM) has been demonstrated to occur for colloidal particles in a suitably arranged post array within a microfluidic device [1]. This effect is based on the interplay of Brownian motion, nonlinear dynamics induced through microstructuring, and nonequilibrium driving, and results in a particle movement opposite to an applied static force. Simultaneously, the migration of a different particle species along the direction of the static force is possible [19], thus providing a new tool for particle sorting in microfluidic device format. The so far demonstrated maximum velocities for micrometer‐sized spheres are slow, i. e., in the order of 10 nm per second. Here, we investigate numerically, how maximum ANM velocities can be significantly accelerated by a careful adjustment of the post size and shape. Based on this numerical analysis, a post design is developed and tested in a microfluidic device made of PDMS. The experiment reveals an order of magnitude increase in velocity.
Stability studies of stationary phases from poly(methyltetradecylsiloxane) sorbed and immobilized onto metalized and unmodified silicas
Authors: Faria Anizio M. , Tonhi Edivan , Collins Kenneth E. , Collins Carol H.
Published: May 2007

Stationary phases for RP‐HPLC were prepared from metalized (titanized and zirconized) and unmodified silica particles using sorbed and immobilized poly(methyltetradecylsiloxane) (PMTDS). Different immobilization procedures, such as gamma irradiation and thermal treatments, were used for the preparation of the immobilized PMTDS phases. The stabilities of these stationary phases were evaluated by passing alkaline (pH 10) mobile phase through 60 mm×3.9 mm columns of the different phases, with periodic tests to evaluate chromatographic performance. The results show that higher stabilities were obtained with stationary phases based on PMTDS immobilized on zirconized silica, these phases being 50% more stable than their titanized silica counterparts and 400% more stable than those based on unmodified silica. These supports provide higher chemical stability to the laboratory‐made stationary phases, when compared with chemically bonded silica‐based phases.
Automated semipreparative purification with mass spectrometric fraction collection trigger: Modeling and experimental evaluation of a setup employing passive splitting
Authors: Steiner Frank , Mahsunah Anis , Arnold Frank , Piecha Thomas , Huber Christian G.
Published: May 2007

A semipreparative HPLC setup was evaluated for automated fractionation with both photometric‐ and mass spectrometric trigger. The goals of the work were to systematically study and optimize the flow‐splitting setup for mass‐directed purifications by mathematical modeling and experimental verification. The system comprised a passive splitting device with make‐up flow capability, which directed a small fraction of the column effluent to the mass spectrometer and the remainder to the fraction collector. Tubing lengths and diameters of the splitter as well as make‐up flow rates were varied in order to address and optimize peak dispersion, delay times between mass detector and fraction collector, and mass spectrometric signal quality. A paraben standard mixture was analyzed and purified on both microparticulate and monolithic columns with 10 mm inner diameter and at typical flow rates of 5–10 mL/min. Fraction purities and recoveries close to 100% were achieved. The system allowed mass‐triggered fractionations on a 1 mg scale at flow rates of 10 mL/min in combination with monolithic columns in less than 2 min. Finally, the system was successfully applied to the fully automated isolation of milligram quantities of degradation products in a pharmaceutical preparation to successfully allow for structure elucidation with NMR spectroscopy.
A notion of selective ultrafilter corresponding to topological Ramsey spaces
Authors: Mijares José G.
Published: May 2007

We introduce the relation of almost‐reduction in an arbitrary topological Ramsey space ℛ as a generalization of the relation of almost‐inclusion on ℕ[∞]. This leads us to a type of ultrafilter 𝒰 ⊆ ℛ which corresponds to the well‐known notion of selective ultrafilter on ℕ. The relationship turns out to be rather exact in the sense that it permits us to lift several well‐known facts about selective ultrafilters on ℕ and the Ellentuck space ℕ[∞] to the ultrafilter 𝒰 and the Ramsey space ℛ. For example, we prove that the open coloring axiom holds on L (ℝ)[𝒰], extending therefore the result from [3] which gives the same conclusion for the Ramsey space ℕ[∞]. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bases, spanning sets, and the axiom of choice
Authors: Howard Paul
Published: May 2007

Two theorems are proved: First that the statement

“there exists a field F such that for every vector space over F, every generating set contains a basis”

implies the axiom of choice. This generalizes theorems of Halpern, Blass, and Keremedis. Secondly, we prove that the assertion that every vector space over ℤ2 has a basis implies that every well‐ordered collection of two‐element sets has a choice function. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A note on stable sets, groups, and theories with NIP
Authors: Onshuus Alf , Peterzil Ya'acov
Published: May 2007

LetMbe an arbitrary structure. Then we say that anM‐formulaφ(x)defines a stable set inMif every formulaφ(x) ∧α(x,y) is stable. We prove: IfGis anM‐definable group and every definable stable subset ofGhasU‐rank at mostn(the samenfor all sets), thenGhas a maximal connected stable normal subgroupHsuch thatG/His purely unstable. The assumptions hold for example ifMis interpretable in an o‐minimal structure.

More generally, anM‐definable setXisweakly stableif theM‐induced structure onXis stable. We observe that, by results of Shelah, every weakly stable set in theories with NIP is stable. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A note on the decidability of exponential terms
Authors: D'Aquino Paola , Terzo Giuseppina
Published: May 2007

In this paper we prove, modulo Schanuel's Conjecture, that there are algorithms which decide if two exponential polynomials in π are equal in ℝ and if two exponential polynomials in π and i coincide in ℂ. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Novel Morphologies Produced by Active Shear Rotation during Injection Molding
Authors: Silva Cristina A. , Viana Júlio C. , Cunha António M.
Published: May 2007

A special mold with mechanically driven mold surface motions (rotation and axial) was developed allowing the imposition of different molding sequences, thus enlarging the possibilities of controlling the thermomechanical environment, and consequently the manipulation of the developed morphology. In this work, centre gated discs were injection molded with distinct rotation velocities of the mold surface. The moldings were characterized by several structure sensitive techniques. The imposition of a mold surface rotation has a marked effect on the morphology of the moldings, with novel molding morphologies being developed: a laminated skin–core structure featuring a dual shish‐kebab structure differently oriented relatively to the flow direction, one in each of the skin layer.

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Poly(vinyl alcohol)/Clay‐Based Nanocomposite Hydrogels: Swelling Behavior and Characterization
Authors: Paranhos Caio M. , Soares Bluma G. , Oliveira Renata N. , Pessan Luiz A.
Published: May 2007

Polymer/clay composite hydrogels were prepared based on PVA hydrogels containing 3–10 wt.‐% MOM. Their microstructure and morphology were studied by FT‐IR, WAXS and SEM, whereas the interactions between MOM and PVA were evaluated by thermal analyses. The swelling ratios for the PVA/MOM hydrogels decrease with increasing MOM content. WAXS results indicate that MOM was intercalates, and DSC results show a strong interaction between PVA and MOM. This interaction results in a stable network, which is confirmed by the elastic modulus and the thermal decomposition behavior of the hydrogels. Therefore, MOM acts as a co‐crosslinker, improving the stability of the network.

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Macromol. Mater. Eng. 5/2007
Authors: Samyn Pieter , Schoukens Gustaaf , Verpoort Francis , Van Craenenbroeck Jeroen , De Baets Patrick
Published: May 2007

Cover: The optical micrographs show thermoplastic polyimide surfaces after sliding at different temperatures. The tribological mechanisms of polymers can be evaluated with Raman spectroscopy, showing three sliding regimes with hydrolysis inducing high friction and low wear, imidisation inducing low friction and high wear and finally melting inducing high friction and high wear. Further details can be found in the article by P. Samyn,* G. Schoukens, F. Verpoort, J. Van Craenenbroeck, and P. De Baets on page 523.
The minmax multidimensional knapsack problem with application to a chance‐constrained problem
Authors: Kress Moshe , Penn Michal , Polukarov Maria
Published: May 2007

In this paper we present a new combinatorial problem, called minmax multidimensional knapsack problem (MKP), motivated by a military logistics problem. The logistics problem is a two‐period, two‐level, chance‐constrained problem with recourse. We show that the MKP is NP‐hard and develop a practically efficient combinatorial algorithm for solving it. We also show that under some reasonable assumptions regarding the operational setting of the logistics problem, the chance‐constrained optimization problem is decomposable into a series of MKPs that are solved separately. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007
A case of Os odontoideum in the palaeopathological record
Authors: Curate F.
Published: May 2007

Os odontoideum is an uncommon abnormality of the second cervical vertebra, the aetiology of which is contentious. Whether congenital or acquired, the condition often results in atlantoaxial instability and subsequent compression of cervical cord or vertebrobasilar vessels. The bioarchaeological study of a medieval sample from the Christian necropolis of Cacela Velha (Algarve, southern Portugal) provided the opportunity to describe one of the first cases of this rare anomaly ever reported in the palaeopathological record. Copyright © 2007 John Wiley & Sons, Ltd.
Diagnostic criteria for developmental dislocation of the hip in human skeletal remains
Authors: Mitchell P. D. , Redfern R. C.
Published: May 2007

Dislocation is the most severe form of developmental dysplasia of the hip (DDH). It significantly impairs hip function in the young, and may lead to debilitating early‐onset osteoarthritis in adults. To our knowledge no thorough study of a large skeletal population has ever been undertaken to determine the wide range of diagnostic criteria for this condition in pathological specimens. To identify these criteria we have analysed the cases of developmental dislocation from a large series of 6000 individuals (6580 hips) from the medieval cemetery at Spitalfields in London, UK. We describe the changes at the true acetabulum, and have created a four‐stage classification of the false acetabulum. The skeletal response to the altered biomechanics and limb shortening that occurs in developmental dislocation is described in the pelvis, lower limb and spine. This includes asymmetric growth in childhood, and asymmetric degenerative change in adulthood. We conclude with a discussion of the clinical literature on developmental dislocation of the hip that will aid palaeopathologists to estimate the symptoms that an excavated individual may have experienced during their lifetime. Copyright © 2007 John Wiley & Sons, Ltd.
1‐allyloxy‐2‐hydroxy‐propyl‐starch: Synthesis and characterization
Authors: Huijbrechts Annemarie A. M. L. , Huang Junrong , Schols Henk A. , van Lagen Barend , Visser Gerben M. , Boeriu Carmen G. , Sudhölter Ernst J. R.
Published: May 2007

New reactive unsaturated starch derivatives, 1‐allyloxy‐2‐hydroxy‐propyl‐starches (AHP‐starches), were synthesized by the reaction of waxy maize starch (WMS) and amylose‐enriched maize starch (AEMS) with allyl glycidyl ether in a heterogeneous alkaline suspension containing NaOH and Na2SO4. The degree of substitution (DS) was determined by 1H NMR spectroscopy, and a DS of 0.20 ± 0.01 was found for both AHP‐WMS and AHP‐AEMS, respectively. The AHP derivatives of WMS and AEMS were further characterized with 1H and 13C NMR. It was shown that the AHP substitution was located on the C‐6 hydroxyl group of the glucose residues in the starch. The substitution pattern of the AHP groups along the polymer chain was randomly clustered, as determined by enzymatic digestion using pullulanase, α‐amylase, and amyloglucosidase, followed by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry analysis of the digestion products. With X‐ray diffraction and scanning electron microscopy, no changes in the granular morphology and crystallinity between the unmodified starches and AHP‐starches were detected. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2734–2744, 2007
Frontal polymerization with monofunctional and difunctional ionic liquid monomers
Authors: Jiménez Zulma , Pojman John A.
Published: May 2007

For the first time, we studied frontal polymerization with ionic liquid monomers. We synthesized a series of compounds from the neutralization reaction between trialkylamines (tributylamine, trihexylamine, trioctylamine, and (2‐dimethylamino)ethyl methacrylate) and acrylic or methacrylic acid. For the ionic liquids prepared from the unreactive amines, frontal polymerization could not be achieved without the addition of a diacrylate. With the addition of a diacrylate, the front velocities were slower than for dodecyl acrylate (with the diacrylate), a compound of comparable molecular weight. Monomers prepared from the (2‐dimethylamino)ethyl methacrylate could support frontal polymerization alone but the front velocities were lower than dodecyl (meth)acrylate. These results are contrasted with recent results of Jiménez et al. for room temperature kinetics. Finally, the polymers prepared were comparable to those prepared by batch curing at 75 °C except for the monomethacrylate ionic liquid, which lost some tertiary amine by dissociation and evaporation. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2745–2754, 2007
Towards a TTOP ground temperature model for mountainous terrain in central‐eastern Norway
Authors: Juliussen Håvard , Humlum Ole
Published: May 2007

The lack of simple mountain permafrost distribution models taking snow depth and site‐specific factors into consideration led us to test the regional Canadian temperature at the top of the permafrost or at the bottom of the seasonally frozen layer (TTOP)‐model in mountain terrain in central‐eastern Norway. The TTOP‐model uses seasonal n‐factors (nt and nf) and air temperature to model the mean annual ground‐surface temperature (MAGST), and a ratio of thawed to frozen thermal conductivity to model the average TTOP.

This study presents 28 and 36 values of nt and nf, respectively. The potential incoming solar radiation, derived in a Geographical Information System (GIS), was used to parameterise nt, and average snow depth was used to parameterise nf. Due to limited information on the subsurface component of the model, only MAGST was modelled. The model was run for the 1961–90 normal period, the Little Ice Age and the year 2050. The model was evaluated against existing model predictions based on bottom temperature of winter snow (BTS) and geophysical soundings. Finally, critical values of snow depth, potential incoming solar radiation and thermal conductivity ratio that constrain negative MAGST and thus permafrost were determined. Copyright © 2007 John Wiley & Sons, Ltd.
The Effect of Transient Conditions on an Equilibrium Permafrost‐climate Model. Dan Riseborough. Permafrost and Periglacial Processes Vol. 18 No. 1 2007, pages 21–32.
Authors: Riseborough Dan
Published: May 2007

The original article to which this Erratum refers was published in Permafrost and Periglacial Processes 18(1) 2007, 21–32. Copyright © 2007 John Wiley & Sons, Ltd.
Recognition and management of actinic keratoses in primary care
Authors: Cerio Rino
Published: May 2007

Actinic keratoses are areas of abnormal epidermal growth that usually form on sun‐exposed skin, and may lead to carcinomas if left untreated. Here, Professor Cerio discusses the clinical features of actinic keratoses and describes the various treatment options. Copyright © 2007 Wiley Interface Ltd
High‐efficiency AlGaN based UV emitters grown on high‐crystalline‐quality AlGaN using grooved AlN layer on sapphire substrate
Authors: Iida K. , Watanabe H. , Takeda K. , Nagai T. , Sumii T. , Nagamatsu K. , Kawashima T. , Balakrishnan K. , Iwaya M. , Kamiyama S. , Amano H. , Akasaki I. , Bandoh A.
Published: May 2007

Crack‐free and low‐dislocation‐density AlGaN was successfully grown on grooved AlN layer. UV light‐emitting diodes (LEDs) with a peak wavelength of 330 nm on these AlGaN films were fabricated. The efficiency of the UV LEDs is found to be strongly affected by the crystalline quality of the underlying AlN. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
One‐step lateral growth for reduction in defect density of a ‐plane GaN on r ‐sapphire substrate and its application in light emitters
Authors: Iida D. , Miura A. , Okadome Y. , Tsuchiya Y. , Kawashima T. , Nagai T. , Iwaya M. , Kamiyama S. , Amano H. , Akasaki I.
Published: May 2007

Low defect density a ‐plane GaN films were successfully grown by sidewall epitaxial lateral overgrowth (SELO) technology. Using this technology, a ‐plane GaN films with atomically flat surface were grown. The threading dislocation and stacking fault densities in the overgrown regions were lower than 106 cm−2 and 103 cm−1, respectively. We also fabricated and characterized a ‐plane‐GaN‐based LEDs using SELO technology. The light output power of a blue‐green LED was shown to monotonically increase with decreasing of threading dislocation density. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of the DNA‐assisted purification of single‐walled carbon nanotubes
Authors: Sánchez‐Pomales G. , Santiago‐Rodríguez L. , Rivera‐Vélez N. E. , Cabrera C. R.
Published: May 2007

Carbon nanotubes (CNTs) possess outstanding structural, mechanical, and electronic properties. Nevertheless, to achieve their full potential, many problems still need to be solved, including the development of an easy purification procedure, the design of functionalization chemistries that result in increased solubility of the CNTs without altering their properties, and the development of a simple route for the attachment of aligned CNTs on solid substrates. DNA offers a solution to the previous challenges. Recently, DNA‐functionalized single‐walled carbon nanotubes (SWNTs) have been prepared by our group and attached on gold by the self‐assembling technique [1, 2]. We therefore decided to perform an in‐depth study of the DNA‐assisted functionalization of SWNTs, which leads to their purification. The results showed a decrease in the SWNTs impurities after functionalization with DNA and demonstrated that the method used is a straightforward and time‐effective route for the purification of SWNTs at room temperature. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transparent carbon nanotube field emission devices for display and lamp
Authors: Cho Yousuk , Lee Sunhee , An Myungchan , Kim Dojin
Published: May 2007

A new, simple method to fabricate transparent carbon nanotube field emission devices is developed. The highly graphitized, single wall carbon nanotubes (SWNTs) are attached to an Sn/ITO glass by the arc discharge method. Post‐heat treatments of the sample below the deformation temperature of soda‐lime glass form a Sn–SWNT composite, and the nanotubes form good mechanical adhesion and electrical contact with the substrates. When the composite is oxidized in air below 400 °C, the Sn particles change to a transparent oxide form. The emission current density of the heat‐treated SWNT–Sn composite is about 1 mA/cm2 at an electric field of 3 V/μm. The emission current density of the SWNT–SnOx composite is similar. However, at a higher oxidation temperature, the emitter shows more stable emission property and longer life time. The transparency of the emitter can be useful in the design of emitter devices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Production of colloidal gold nanoparticles by picosecond laser ablation in liquids
Authors: Giorgetti E. , Giusti A. , Laza S. C. , Marsili P. , Giammanco F.
Published: May 2007

We produced gold nanoparticles in water by picosecond laser ablation at 532 nm and 1064 nm. We used the amino‐terminated dendrimer PAMAM G5 as stabilizing agent. At 532 nm, the production process exhibits a threshold that is about 10 times lower than at 1064 nm and rapidly saturates. The fast saturation is due to single photon absorption of the ablating beam and a possible further energy loss due to photofragmentation of existing nanoparticles. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simple route for intermatrix synthesis of polymer stabilized core‐shell metal nanoparticles for sensor applications
Authors: Muraviev D. N. , Macanás J. , Esplandiu M. J. , Farre M. , Muñoz M. , Alegret S.
Published: May 2007

In this paper we report the novel simple route for the inter‐matrix synthesis and characterization of Polymer Stabilized Metal Nanoparticles (PSMNPs) with core‐shell structure. The proposed approach is based on the use of functionalized polymeric membranes (FPM) as a nanoreactor for both to synthesize and to characterize the composition and morphology of PSMNPs. The desired functionalization is achieved by the chemical grafting of the desired functional groups (sulphonic in our case) to the polymeric matrix. The proposed approach is illustrated by the results obtained by studying the intermatrix synthesis of Pt@Cu‐core‐shell PSMNPs of different compositions in sulfonated poly(ether ether ketone) (SPEEK) membranes. The electrochemical response of amperometric sensors prepared by using SPEEK‐Pt@Cu‐PSMNP nanocomposite membranes as a sensing element has been shown to increase with the loading of the shell‐forming metal (Pt). The presence of Pt@Cu‐PSMNC inside the membrane not only substantially improves the electric conductivity of the polymer, but also testifies to manifestation of clearly pronounced strong electrocatalytic activity of Pt@Cu‐PSMNC towards analyte under study (H2O2). (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultra high sensitive detection of mechanical resonances of nanowires by field emission microscopy
Authors: Perisanu S. , Vincent P. , Ayari A. , Choueib M. , Guillot D. , Bechelany M. , Cornu D. , Miele P. , Purcell S. T.
Published: May 2007

We present here highly sensitive measurements of nanowire mechanical resonances by analyzing Field Emission Microscopy (FEM) images from the nanowires while they are excited by sinusoidally time‐varying voltages. Numerical analysis of the image blurring during frequency sweeps through resonances are shown to allow detection with ≃100× higher sensitivity as compared to our previous measurements where they were detected by the changes in the total field emission (FE) current. Furthermore since FEM approximately measures the end angle of the nanowire, this detection is more sensitive to higher resonance modes which in general have much smaller amplitudes. Observation of the mechanical response of SiC nanowires in FEM shows that they almost always present non linear mechanical behavior with large hysteresis and abrupt jump effects in their frequency response that are related to the large applied electric field. We approach the linear regime by reducing the excitation voltage and by using the sensitive image detection method. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Localized quantum spin reversal by spin injection in a spin quantum dot: A model calculation
Authors: Kokado Satoshi , Ueda Kazumasa , Harigaya Kikuo , Sakuma Akimasa
Published: May 2007

We theoretically study the reversal of localized quantum spin induced by spin injection in a spin quantum dot, where the dot has a localized quantum spin and it is connected to the left and the right electrodes. We consider a situation in which up spins are sequentially injected from the left electrode into the dot, and an exchange interaction acts between the injected spins and the localized spin. When the right electrode interface has energy levels of conduction electrons with only down spin, we obtain the reversal time of localized spin and the time dependence of the expectation value of localized spin, using a simple approach based on the time dependent Schrödinger equation. It is also shown that a system with the nonmagnetic right electrode interface exhibits the spin reversal or nonreversal depending on the exchange interaction. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of InAs quantum wires on (001)InP: toward the realization of VCSEL structures with a stabilized polarization
Authors: Lamy J.‐M. , Levallois C. , Nakhar A. , Caroff P. , Paranthoen C. , Piron R. , Le Corre A. , Ramdane A. , Loualiche S.
Published: May 2007

We propose a new type of long‐wavelength vertical cavity surface emitting laser (VCSEL) which consists of quantum wires (QWires) layers of InAs/InGaAsP grown on InP(001) and dielectrics Bragg mirrors, in order to control the in plane polarization of output power. QWires and quantum wells growth are performed by molecular beam epitaxy. QWires present a strong photoluminescence dependence to the polarization in contrast to the quantum wells, a polarization rate of 33% is measured. The optically pumped VCSEL is fabricated by metallic bonding, which allows the deposition of two dielectrics Bragg mirrors. The VCSEL with an active region based on InGaAs/InGaAsP quantum wells exhibits a lasing emission at 1.578 µm at room temperature under continuous wave operation. The VCSEL with an active region based on quantum wires shows a luminescence at 1.53 µm strongly polarized along the direction [1$ \bar 1 $0] which is promising for the stabilization of in plane polarization of VCSEL emission. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The biocompatibility microorganisms‐carbon nanostructures for applications in microbial fuel cells
Authors: Morozan A. , Stamatin L. , Nastase F. , Dumitru A. , Vulpe S. , Nastase C. , Stamatin I. , Scott K.
Published: May 2007

Bionanocomposites Staphylococcus aureus /carbon nanotubes were prepared and their biocompatibility with different species of carbon nanotubes (CNTs) evaluated in terms of their incorporation into a microbial fuel cell (MFC) anodic design. Multi wall carbon nanotubes (MWNTs) with various morphologies and structures, as received, and synthesized by the pyrolysis of novolac with ferrocene addition were used. MWNTs were characterized by TEM and FT‐IR spectroscopy. Optical microscopy with fluorescent quantum dots (QDs) have been used for bio‐labeling, microorganisms‐CNTs biocompatibility and rapid identification of the colonies developed. Designed BNCs are good culture cells media and the electrodes based on synthesized CNTs could be used with good effects in MFCs, from the point of view of bacteria biocompatibility. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetotransport in high mobility epitaxial graphene
Authors: Berger Claire , Song Zhimin , Li Xuebin , Wu Xiaosong , Brown Nate , Maud Duncan , Naud Cécile , de Heer Walt A.
Published: May 2007

Epitaxial graphene layers grown on single‐crystal SiC have large structural coherence domains and can be easily patterned into submicron structures using standard microelectronics lithography techniques. Patterned structures show two‐dimensional electron gas properties with mobilities exceeding 3 m2/Vs. Magnetotransport measurements (Shubnikov–de Haas oscillations) indicate that the transport properties are dominated by the highly doped graphene layer at the silicon carbide interface. They reveal the Dirac nature of the charge carriers as predicted for a single graphene layer. The properties of Dirac fermions can be conveniently explored in epitaxial graphene with long electronic phase coherence at the micron scale. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic properties of nickel–zinc ferrite nanoparticles synthesized by coprecipitation
Authors: Corral‐Flores V. , Bueno‐Baqués D. , Paraguay‐Delgado F. , Botez C. E. , Ibarra‐Gómez R. , Ziolo R.
Published: May 2007

The influence of Zn substitution in the magnetic properties of a nanoscale system Ni1–x Znx Fe2O4 (where x = 0.0, 0.25, 0.50 and 0.75) was studied. The ferrites were synthesized by the coprecipitation technique. Transmission electron microscopy revealed a particle size around 4–15 nm, increasing with Zn content. FC/ZFC curves showed a typical superparamagnetic behavior in all samples. It was found that Zn substitution affects both the blocking temperature and the magnetization. The maximum magnetization at room temperature was 48 emu/g for the sample x = 0.50. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Construction of a two‐dimensional molecule–nanoparticle network using iron(II) bis(terpyridine) complex formation for molecular‐device applications
Authors: Hobara D. , Kondo S. , Choi M.‐S. , Ishioka Y. , Hirata S. , Murata M. , Azuma K. , Kasahara J.
Published: May 2007

We report a novel method to construct a two‐dimensional network of gold nanoparticles and metal complex molecules. Terpyridine derivatives having a thiol group are adsorbed on a gold nanoparticle surface through formation of a gold–sulfur bond. A monolayer of nanoparticles is then formed on the water surface, then transferred onto a Si/SiO2 substrate. The introduction of Fe2+ from a Fe(BF4)2 solution forms an iron(II) bis(terpyridine) complex, which simultaneously forms a network where the complex molecules interlink adjacent nanoparticles. The conductivity of the network, formed by the conjugated terpyridine derivative, is 4 or 5 orders of magnitude higher than that of non‐conjugated derivatives. Conductivity is modulated by gate voltage when a conjugated derivative is used but not when a non‐conjugated derivative is used. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Relaxor‐based thin film memories and the depolarizing field problem
Authors: Marqués Manuel I. , Aragó Carmen
Published: May 2007

A simple model for a thin film memory based on a first neighbor interacting model is studied in detail. We have found that the minimum possible value for the thickness (D) as a function of the lateral size of the memory (L), the screening of the charges at the substrate (S) and the strength of the ferroelectric interaction (J), in order to obtain spontaneous polarization is D = SL /2J. We propose a new mechanism to obtain miniaturization of thin film memories to a single layer based on the use of relaxor ferroelectrics instead of regular ferroelectrics. Under the hypothesis of an internal organization of the random fields inside the nanofilm we show analytically how it should be possible to miniaturize the memory to a width as small as D = 1 for any value of L, J and S. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Carbon‐isotopic composition of soil‐respired carbon dioxide in static closed chambers at equilibrium
Authors: Mora Germán , Raich James W.
Published: May 2007

The carbon‐isotopic composition (δ13C) of soil‐respired CO2 has been employed to evaluate soil carbon‐cycling processes and the contribution of soil CO2 emissions to canopy and tropospheric air. These evaluations can be successful only when accurate isotope values of soil‐respired CO2 are available. Here, we tested the robustness of δ13C values of soil‐respired CO2 obtained after long incubations in static closed chambers that were initially flushed with soil air. The rationale of this approach is that the equilibrium carbon‐isotope values of chamber‐headspace CO2 are theoretically equal to those of CO2 produced within the soil. Static closed chambers were installed in replicated grass monocultures, and measurements of headspace CO2 concentrations and δ13C values were performed at regular time intervals for 24 h in July 2005. The results revealed no significant effects of grass species on headspace CO2 concentrations or δ13C values (repeated measures analysis of variance (ANOVA), P > 0.1). As predicted by theory, isotope values asymptotically approached equilibrium conditions, which in our experimental setting occurred after 10 h. This good match between model predictions and our results suggests that an accurate determination of δ13C values of CO2 produced within soils is obtained through the isotopic measurement of chamber‐headspace CO2 once equilibrium conditions have been reached with the underlying soils. An additional advantage of this approach is that only one sample per chamber is required, which, combined with the low uncertainties of these measurements, facilitates the investigation of the spatial (landscape) variability of soil‐respired CO2. Copyright © 2007 John Wiley & Sons, Ltd.