bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a quality control method for the characterization of oligonucleotides by capillary zone electrophoresis‐electrospray ionization‐quadrupole time of flight‐mass spectrometry
Authors: Willems An V. , Deforce Dieter L. , Van Peteghem Carlos H. , Van Bocxlaer Jan F.
Published: March 2005

A capillary zone electrophoresis‐negative electrospray ionization‐quadrupole time of flight‐mass spectrometric method was developed for the characterization of oligonucleotides after synthesis, using model compounds. The major difficulty is the adduction of metal cations to the polyanionic backbone of the oligonucleotide sample, resulting in complex spectra and decreased sensitivity. Several approaches were investigated to circumvent this problem. Separation was performed in an ammonium carbonate buffer. During separation, the interfering metal ions were exchanged for ammonium ions, which are less tightly bound to the oligonucleotide when ionized. The influence of the addition of piperidine and imidazole or trans‐1,2‐diaminocyclohexane‐N,N,N',N'‐tetraacetic acid (CDTA) to the running buffer for further reduction of cation adduction was investigated. Addition of CDTA to the buffer system resulted in a deconvoluted spectrum with very little adducts. On‐line sample stacking proved vital to preconcentrate the samples. The pH and the concentration of the ammonium carbonate buffer as well as the electrophoresis voltage were optimized to achieve the best signal response for the oligonucleotides and a maximum reduction of the cation adducts as well as a short analysis time. Finally, the sheath liquid composition was examined for further improvement of the signal. The developed method was used to analyze different oligonucleotides (5000–9200 Da) in light of its use as a final quality control method for oligonucleotides in terms of purity and sequence homogeneity of the synthesized products. In all cases, very little adducts were observed in the deconvoluted spectra, and the relative errors of the measured molecular masses ranged from 3 to 35 ppm.
Combining capillary electrophoresis with mass spectrometry for applications in proteomics
Authors: Simpson David C. , Smith Richard D.
Published: March 2005

Mass spectrometry (MS)‐based proteomics is currently dominated by the analysis of peptides originating either from digestion of proteins separated by two‐dimensional gel electrophoresis (2‐DE) or from global digestion; the simple peptide mixtures obtained from digestion of gel‐separated proteins do not usually require further separation, while the complex peptide mixtures obtained by global digestion are most frequently separated by chromatographic techniques. Capillary electrophoresis (CE) provides alternatives to 2‐DE for protein separation and alternatives to chromatography for peptide separation. This review attempts to elucidate how the most promising CE modes, capillary zone electrophoresis (CZE) and capillary isoelectric focusing (CIEF), might best be applied to MS‐based proteomics. CE‐MS interfacing, mass analyzer performance, column coating to minimize analyte adsorption, and sample stacking for CZE are considered prior to examining numerous applications. Finally, multidimensional systems that incorporate CE techniques are examined; CZE often finds use as a fast, final dimension before ionization for MS, while CIEF, being an equilibrium technique, is well‐suited to being the first dimension in automated fractionation systems.
Interpolation processes using multivariate geostatistics for mapping of climatological precipitation mean in the Sannio Mountains (southern Italy)
Authors: Diodato Nazzareno , Ceccarelli Michele
Published: March 2005

The spatial variability of precipitation has often been a topic of research, since accurate modelling of precipitation is a crucial condition for obtaining reliable results in hydrology and geomorphology. In mountainous areas, the sparsity of the measurement networks makes an accurate and reliable spatialization of rainfall amounts at the local scale difficult. The purpose of this paper is to show how the use of a digital elevation model can improve interpolation processes at the subregional scale for mapping the mean annual and monthly precipitation from rainfall observations (40 years) recorded in a region of 1400 km2 in southern Italy. Besides linear regression of precipitation against elevation, two methods of interpolation are applied: inverse squared distance and ordinary cokriging. Cross‐validation indicates that the inverse distance interpolation, which ignores the information on elevation, yields the largest prediction errors. Smaller prediction errors are produced by linear regression and ordinary cokriging. However, the results seem to favour the multivariate geostatistical method including auxiliary information (related to elevation). We conclude that ordinary cokriging is a very flexible and robust interpolation method because it can take into account several properties of the landscape; it should therefore be applicable in other mountainous regions, especially where precipitation is an important geomorphological factor. Copyright © 2005 John Wiley & Sons, Ltd.
Complex chromosome 22 rearrangements in astrocytic tumors identified using microsatellite and chromosome 22 tile path array analysis
Authors: Seng Tzer Jing , Ichimura Koichi , Liu Lu , Tingby Ola , Pearson Danita M. , Collins V. Peter
Published: March 2005

Many studies have reported chromosome 22 as being abnormal in astrocytic tumors. In an attempt to map precisely the abnormal region or regions that potentially harbor tumor‐suppressor genes or oncogenes, we constructed a chromosome 22 tile path array covering 82% of 22q with the use of 441 chromosome 22 clones. A 10‐Mb whole‐genome array consisting of 270 clones from all autosomes was included in the array. A total of 126 astrocytic tumors—5 diffuse astrocytomas (A), 29 anaplastic astrocytomas (AA), and 92 glioblastomas (GB)—were examined for chromosome 22 alterations both by microsatellite analysis (using 28 markers to identify allelic imbalance) and with the tile path array. The results showed that chromosome 22 alterations in astrocytic tumors could be complex. A number of tumors had a combination of deletions with and without reduplication of the retained chromosome, as well as copy number gains and amplifications. In two glioblastomas, overlapping homozygous deletions were identified that involved three genes (DEPDC5/KIAA0645, YWHAH, C22ORF24/HSN44A4A). The terminal region telomeric to the clone RP3‐398C22 appeared to be the most frequently deleted region. The estimated incidence of any chromosome 22 alteration was 5% in A, 33% in AA, and 38% in GB. This study demonstrated the advantages of combining array comparative genomic hybridization and microsatellite analysis in elucidating complex genomic rearrangements in primary human tumor tissue. Supplementary material for this article can be found on the Genes, Chromosomes and Cancer website at http://www.interscience.wiley.com/jpages/1045‐2257/suppmat/index.html. © 2005 Wiley‐Liss, Inc.
Microstructured scaffolds for liver tissue cultures of high cell density: Morphological and biochemical characterization of tissue aggregates
Authors: Eschbach Erik , Chatterjee Shyam S. , Nöldner Michael , Gottwald Eric , Dertinger Hermann , Weibezahn Karl‐Friedrich , Knedlitschek Gudrun
Published: March 2005

Very high cell densities and optimal vascularization characterize among others organs and tissues in vivo. In order to study organ‐specific functions in vitro or to make use of them in medical devices/treatments in the future, this natural architecture should be rebuilt. An important aspect in this context is the appropriate ratio of medium to cell volume being so far not optimally reestablished in most of the currently available in vitro systems. To improve such culture conditions, we constructed a microstructure to culture hepatocytes and (without any addition of extracellular matrix material) characterized liver tissue in the form of evenly sized aggregates. The liver‐specific differentiation status of such aggregates was monitored by their ability to perform CYP450 dependent xenobiotic metabolism along with the measurement of albumin secretion. Freshly isolated adult rat hepatocytes show an initial loss of total CYP450 content and of associated activities (mixed function oxidases). However, in the aggregate system, this level did not decrease further but remained stable or even increased throughout the culture period of 10–13 days. The CYP450 dependent metabolism of the hepatocytes is able to respond to classic inducing agents. The described culture efficiently supports liver‐specific functions of adult rat hepatocytes and seems to be suited not only for use in an extracorporeal liver device but also for the formation of evenly sized small aggregates to be of use in transplantation of differentiated liver tissue. Moreover, after design variations, the microstructure can be applied for functional analysis of metabolically active hepatocytes as well as for toxicological and pharmacological validation. © 2005 Wiley‐Liss, Inc.
Perinucleolar compartment and transformation
Authors: Kopp K. , Huang S.
Published: March 2005

The perinucleolar compartment (PNC) is a sub‐nuclear structure that preferentially localizes to the nucleolar periphery. The PNC is found predominantly in transformed cells both in vitro and in vivo. PNC prevalence (the percentage of cells containing at least one PNC) positively correlates with the progression of breast cancer and patient survival. PNCs are highly enriched with newly synthesized RNA polymerase III transcripts and RNA‐binding proteins. The structural integrity of the PNC is dependent upon the transcription of these RNAs and a critical level of the polypyrimidine tract binding (PTB) protein, as assayed by the localization of other PNC‐associated proteins. These observations suggest a model in which the PNC is a dynamic, functional organelle that forms under specific physiological conditions favoring cellular transformation and might be involved in the metabolism of RNA polymerase III transcripts. © 2005 Wiley‐Liss, Inc.
Bioprocesses for the removal of nitrogen oxides from polluted air
Authors: Jin Yaomin , Veiga María C , Kennes Christian
Published: March 2005

Nitrogen oxides (NOx) of environmental concern are nitrogen monoxide (NO) and nitrogen dioxide (NO2). They are hazardous air pollutants that lead to the formation of acid rain and tropospheric ozone. Both pollutants are usually present simultaneously and are, therefore, called NOx. Another compound is N2O which is found in the stratosphere where it plays a role in the greenhouse effect. Concern for environmental and health issues coupled with stringent NOx emission standards generates a need for the development of efficient low‐cost NOx abatement technologies. Under such circumstances, it becomes mandatory for each NOx‐emitting industry or facility to opt for proper NOx control measures. Several techniques are available to control NOx emissions: selective catalytic reduction (SCR), selective non‐catalytic reduction (SNCR), adsorption, scrubbing, and biological methods. Each process offers specific advantages and limitations. Since bioprocesses present many advantages over conventional technologies for flue gas cleaning, a lot of interest has recently been shown for these processes. This article reviews the major characteristics of conventional non‐biological technologies and recent advances in the biological removal of NOx from flue gases based on the catalytic activity of either eucaryotes or procaryotes, ie nitrification, denitrification, the use of microalgae, and a combined physicochemical and biological process (BioDeNOx). Relatively uncomplicated design and simple operation and maintenance requirements make biological removal a good option for the control of NOx emissions in stationary sources. Copyright © 2005 Society of Chemical Industry
Development and characterisation of a molecularly imprinted polymer prepared by precipitation polymerisation for the determination of phenylurea herbicides
Authors: Carabias‐Martínez Rita , Rodríguez‐Gonzalo Encarna , Herrero‐Hernández Eliseo , Díaz‐García Marta Elena
Published: March 2005

New materials based on molecularly imprinted polymers (MIPs) have been developed for use as sorbents in solid phase extraction to preconcentrate some urea herbicides. In the preconcentration step, different molecularly imprinted polymers were tested using methacrylic acid (MAA) and 2‐(trifluoromethyl)acrylic acid (TFMAA) as functional monomers, and linuron and isoproturon as templates. The best results were obtained when the polymer was synthesised using MAA with isoproturon as template. Another parameter evaluated was the way in which the polymer was obtained. We observed that the imprinted polymers obtained by precipitation displayed a greater capacity to retain the phenylureas. Studies conducted using scanning electron microscopy (SEM) revealed that the bulk polymerisation method is far from ideal owing to the random shape and size distribution of the particles obtained, whereas when polymerisation was carried out in precipitation microspheres were obtained. In order to confirm the interaction between the functional monomer and the template, 1H NMR (CD2Cl2) analyses were conducted. The results obtained suggest that the hydrogen and/or nitrogen of the amino group of the template would be involved in the formation of hydrogen bonds with the functional monomer. The imprinted polymer obtained by precipitation polymerisation with MAA as functional monomer and isoproturon as template can be applied to preconcentrate phenylureas when the sample is dissolved in toluene. The proposed methodology was employed to evaluate polymer selectivity towards humic acids and towards other herbicides.
New Evidences of Glass Transitions and Microstructures of Soy Protein Plasticized with Glycerol
Authors: Chen Pu , Zhang Lina
Published: March 2005

Summary: Soy protein isolate (SPI) and glycerol were mixed under mild (L series) and severe (H series) mixing conditions, respectively, and then were compression‐molded at 140 °C and 20 MPa to prepare the sheets (SL and SH series). The glass transition behaviors and microstructures of the soy protein plasticized with glycerol were investigated carefully by using differential scanning calorimetry and small‐angle X‐ray scattering. The results revealed that there were two glass transitions in the SPI/glycerol systems. When the glycerol contents ranged from 25 to 40 wt.‐%, all of the SL‐ and SH‐series sheets showed two glass transition temperatures (Tg1 and Tg2) corresponding to glycerol‐rich and protein‐rich domains, respectively. The Tg1 values of the sheets decreased from −28.5 to −65.2 °C with an increase of glycerol content from 25 to 50 wt.‐%, whereas the Tg2 values were almost invariable at about 44 °C. The results from wide‐angle X‐ray diffraction and small‐angle X‐ray scattering indicated that both protein‐rich and glycerol‐rich domains existed as amorphous morphologies, and the radii of gyration (Rg) of the protein‐rich domains were around 60 nm, a result suggesting the existence of stable protein domains. The results above suggest that protein‐rich domains were composed of the compact chains of protein with relatively low compatibility to glycerol and glycerol‐rich domains consisted of relative loose chains that possessed good compatibility with glycerol. The significant microphase separation occurred in the SPI sheets containing more than 25 wt.‐% glycerol, with a rapid decrease of the tensile strength and Young's modulus.

Schematic of the microstructures of glycerol‐plasticized soy protein with glycerol‐rich and protein‐rich domains.

magnified image

Schematic of the microstructures of glycerol‐plasticized soy protein with glycerol‐rich and protein‐rich domains.
Synthesis of Diphenylamine‐Substituted Phenylazomethine Dendrimers and the Performance of Organic Light‐Emitting Diodes
Authors: Cho Jun‐Sang , Kimoto Atsushi , Higuchi Masayoshi , Yamamoto Kimihisa
Published: March 2005

Summary: We have designed and synthesized novel diphenylamine‐substituted phenylazomethine dendrimers (DP‐Gn, n = 1, 2) as hole‐transport materials for organic light‐emitting diodes (OLEDs). These dendrimers similar to phenylazomethine dendrimers showed a stepwise metal complexation with metal ions. They have good multi‐redox properties attributed to the terminal amine moieties and excellent thermal stabilities. Double layer EL devices utilizing the dendrimers as a hole‐transport material and Alq3 as the emitting and electron transport materials were fabricated. The EL performances of the devices increased with higher dendrimer generations. Moreover, by using the metal ion (0.5 equiv. SnCl2)‐complexed DP‐G2 dendrimers, the luminance and EL efficiency of the devices were drastically increased by more than double and over 30%, respectively. These metal complexable phenylazomethine dendrimers are novel and promising materials for highly efficient OLEDs.

Structure of the diphenylamine‐substituted phenylazomethine dendrimer DP‐G2.

magnified image

Structure of the diphenylamine‐substituted phenylazomethine dendrimer DP‐G2.
Pulsed Laser Polymerization of Styrene in Microemulsion: Determination of Band Broadening in Size Exclusion Chromatography with Multimodal Distributions
Authors: Mader Christoph , Schnöll‐Bitai Irene
Published: March 2005

Summary: Styrene was polymerized in microemulsion by pulsed laser radiation. The resulting multimodal distributions are composed of equidistant Poisson distributions as bimolecular termination occurs mainly during the short laser pulses. For nearly all distributions the first peak was almost base line separated and higher order peaks were clearly distinguishable. The width of the first and second peak was used to determine the extent of band broadening (bb), σ, as a function of the retention volume. Results were collected for three combinations of columns differing in their separation range. These values and those obtained from anionically polymerized polystyrene standards show the same dependence on the retention volume and can be described by the van Deemter equation even beyond the exclusion limit. The results are interpreted in the context of obstructed diffusion and the van Deemter equation is extended to take into account the contribution of the individual columns with different pore sizes. Both theory and experiment advocate a non‐uniform bb thus emphasizing the necessity for the determination of bb for a given set of columns.

Comparison of experimental results (squares – standards, circles PLP‐ME samples) and theory (full line: according to Equation (6c), broken lines: individual contributions of the columns).

magnified image

Comparison of experimental results (squares – standards, circles PLP‐ME samples) and theory (full line: according to Equation (6c), broken lines: individual contributions of the columns).
Adenovirus‐5 E1A suppresses differentiation of 3T3 L1 preadipocytes at lower levels than required for induction of apoptosis
Authors: Cao Jun , Arulanandam Rozanne , Vultur Adina , Preston Thomas , Jaronczyk Katarzyna , Tomai Evangelia , Zandi Keivan , Raptis Leda
Published: March 2005

To investigate the functional relationship between the ability of the adenovirus‐5 E1A oncogene product to transform with its ability to block adipocytic differentiation and induce apoptosis, we expressed E1A in the 3T3 L1 preadipocytic cell line. The results demonstrate a dramatic, quantitative reciprocal regulation of differentiation and several transformation‐associated properties in response to graded levels of E1A expression, with the suppression of differentiative capacity, focus formation, and anchorage‐independent proliferation requiring increasing levels of E1A. Progressively higher E1A levels were accompanied by apoptosis induction. The effect of E1A upon adipocytic differentiation as well as transformation and apoptosis required binding to the retinoblastoma‐susceptibility gene product. These data reveal a dissociation between E1A signals leading to transformation, suppression of differentiation and induction of apoptosis, based on levels of expression. © 2005 Wiley‐Liss, Inc.
Clinical and molecular aspects of the myotonic dystrophies: A review
Authors: Machuca‐Tzili Laura , Brook David , Hilton‐Jones David
Published: March 2005

Type 1 myotonic dystrophy or DM1 (Steinert's disease), which is the commonest muscular dystrophy in adults, has intrigued physicians for over a century. Unusual features, compared with other dystrophies, include myotonia, anticipation, and involvement of other organs, notably the brain, eyes, smooth muscle, cardiac conduction apparatus, and endocrine system. Morbidity is high, with a substantial mortality relating to cardiorespiratory dysfunction. More recently a second form of multisystem myotonic disorder has been recognized and variously designated as proximal myotonic myopathy (PROMM), proximal myotonic dystrophy (PDM), or DM2. For both DM1 and DM2 the molecular basis is expansion of an unstable repeat sequence in a noncoding part of a gene (DMPKin DM1 andZNF9in DM2). There is accumulating evidence that the basic molecular mechanism is disruption of mRNA metabolism, which has far‐reaching effects on many other genes, in part through the induction of aberrant splicing, explaining the multisystemic nature of the disease. The unstable nature of the expansion provides a molecular explanation for anticipation. This review emphasizes the clinical similarities and differences between DM1 and DM2. It examines current views about the molecular basis of these disorders, and contrasts them with other repeat expansion disorders that have increasingly been recognized as a cause of neurological disease. Muscle Nerve, 2005
Practice parameter: Utility of electrodiagnostic techniques in evaluating patients with suspected peroneal neuropathy: An evidence‐based review
Authors: Marciniak Christina , Armon Carmel , Wilson John , Miller Robert
Published: March 2005

An evidence‐based review of electrodiagnostic (EDX) techniques in the evaluation of peroneal neuropathy was conducted to determine whether these techniques are useful for diagnosis and prognostication in this disorder. A Medline search and a review of relevant sources were performed in 1999 and updated through July 2003 to identify articles describing the use of EDX in patients suspected to have peroneal neuropathy. From the 499 articles identified, 112 articles describing motor and sensory nerve conduction studies and needle electromyography in peroneal neuropathy were reviewed in detail; 11 articles met the predetermined literature inclusion criteria for the adequacy of EDX techniques employed. Six articles provided Class III evidence in support of a role for nerve conduction studies in making the diagnosis of peroneal neuropathy; five articles provided Class IV evidence. Implicit in making the diagnosis were normal EDX findings outside the distribution of the peroneal nerve. The current literature supports the use of EDX in patients with suspected peroneal neuropathy (Level C recommendation). Muscle Nerve, 2005
Tropisetron: Optimal dosage for children in prevention of chemotherapy‐induced vomiting
Authors: Cappelli Carlo , Ragni Giuseppina , De Pasquale Maria Debora , Gonfiantini Michaela , Russo Daria , Clerico Anna
Published: March 2005

The antiemetic efficacy and tolerability of Tropisetron (Navoban®, Novartis Pharma Switzerland AG, Bern), a selective 5‐hydroxytriptamine receptor antagonist, has been assessed in the prevention of acute vomiting in children receiving chemotherapy for solid tumors. Tropisetron iv was given 30 min before administration of chemotherapy at a dose of 5 mg in children <20 kg body weight and at a dose of 10 mg in those >20 kg. A total of 50 children were studied in 189 courses of chemotherapy. Control of emesis was defined as total in absence of acute vomiting, as major if 1 or 2 events of acute vomiting occurred, and as not controlled if >2 events of acute vomiting occurred. Response was studied, taking into account Tropisetron dosage, degree of emetogenicity of the chemotherapeutic agents in pretreated and non‐pretreated patients, and according to age groups. Tropisetron, administered in a single daily dose of 8–12 mg/m2, was found to be very effective in completely controlling acute emesis in 92% of the courses of moderately and highly emetogenic chemotherapy administered to pediatric patients with solid tumors. Moreover, Tropisetron, at this dosage, did not lead to any adverse effects. Pediatr Blood Cancer 2005; 45:48–53. © 2005 Wiley‐Liss, Inc.
Transition structures and reaction barriers in the styrene–acrylonitrile copolymerization system according to quantum mechanical calculations
Authors: Kaim Andrzej , Megiel Elżbieta
Published: March 2005

The geometries and electronic properties of substrates, transition structures (TS), and product radicals in modeled elementary propagation reactions were studied for the styrene–acrylonitrile monomer system by use of quantum‐mechanical calculations: (DFT/B3‐LYP/6–31G(d), ROMP2/6–311+G(3df,2p)//DFT/B3‐LYP/6–31G(d), and DFT/B3‐LYP/6–311+G(3df,2p)//DFT/B3‐LYP/6–31G(d)) and for some parameters, the high‐level composite method G3 (Gaussian‐3, G3/MP2). Activation enthalpies (ΔHact) and reaction enthalpies (ΔHr) for modeled propagation reactions at 298.15 K were evaluated. The enthalpy of activation energy (ΔHact, kJ/mol) for the investigated elementary reactions rises for the B3‐LYP calculation in the following order: (CH3A•+S) < (CH3A•+A) < (CH3S•+A) < (CH3S•+S). For three propagation reactions, (CH3A•+A), (CH3A•+S), and (CH3S•+A), correlation between reaction enthalpy and enthalpy of activation suggests weak or negligible polar effects reflecting the Evans–Polanyi relation. However, from the electron affinities and ionization energies values data, it is not excluded that at least for [CH3A•+S[b]] and [CH3S•+A[b]] reactions, nucleophilic and electrophilic polar effects, respectively, can also be expected. The dependencies between TS geometries, electronic parameters, and enthalpic effects suggest the presence of a steric factor in all TS, including its exceptionally high contribution to the activation enthalpy for the CH3S•+S addition. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1827–1844, 2005
Toughness mechanism of polypropylene/elastomer/filler composites
Authors: Zhang Ling , Li Chunzhong , Huang Rui
Published: March 2005

The toughening mechanisms of polypropylene filled with elastomer and calcium carbonate (CaCO3) particles were studied. Polypropylene/elastomer/CaCO3 composites were prepared on a twin‐screw extruder with a particle concentration of 0–32 vol %. The experiments included tensile tests, notched Izod impact tests, scanning electron microscopy, and dynamic mechanical analysis. Scanning electron microscopy showed that the elastomer and CaCO3 particles dispersed separately in the matrix. The modulus of the composites increased, whereas the yield stress decreased with the filler concentration. The impact resistance showed a large improvement with the CaCO3 concentration. At the same composition (80/10/10 w/w/w), three types of CaCO3 particles with average diameters of 0.05, 0.6, and 1.0 μm improved the impact fracture energies comparatively. The encapsulation structure of the filler by the grafting elastomer had a detrimental effect on the impact properties because of the strong adhesion between the elastomer and filler and the increasing ligament thickness. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1113–1123, 2005
Recent advances in luminescence dating of Late Pleistocene (cold‐climate) aeolian sand and loess deposits in western Europe
Authors: Koster Eduard A.
Published: March 2005

Aeolian dune and sand sheet deposits, as well as sandy loess and loess deposits, cover extensive areas in the northwest and central European Lowlands. These sediments have received a great deal of attention during recent decades, leading to a variety of litho‐ and chronostratigraphic classifications. Although the aeolian stratigraphic record is known in great detail in most European countries, there is still discussion about the exact timing of phases of aeolian deposition, due to the fact that dates usually relate to materials reflecting phases of non‐deposition. This paper presents an overview of recent advances in luminescence dating of cold‐climate, predominantly Last Glacial (Weichselian), aeolian sand and loess deposits. These dates are compared with the results of conventional radiocarbon and AMS‐dating of palaeosols and other stratigraphic marker horizons. Although optical luminescence dating techniques, especially of the quartz fraction, appears to provide reliable ages for aeolian sediments in western Europe ranging in age from a few decades to at least 150 ka BP, there still are various uncertainties in the interpretation of luminescence ages due to methodological problems, difficulties in field extrapolation of stratigraphic relationships, and limited independent chronological control. Copyright © 2005 John Wiley & Sons, Ltd.
Identification and distribution of protein families in 120 completed genomes using Gene3D
Authors: Lee David , Grant Alastair , Marsden Russell L. , Orengo Christine
Published: March 2005

Using a new protocol, PFscape, we undertake a systematic identification of protein families and domain architectures in 120 complete genomes. PFscape clusters sequences into protein families using a Markov clustering algorithm (Enright et al., Nucleic Acids Res 2002;30:1575–1584) followed by complete linkage clustering according to sequence identity. Within each protein family, domains are recognized using a library of hidden Markov models comprising CATH structural and Pfam functional domains. Domain architectures are then determined using DomainFinder (Pearl et al., Protein Sci 2002;11:233–244) and the protein family and domain architecture data are amalgamated in the Gene3D database (Buchan et al., Genome Res 2002;12:503–514). Using Gene3D, we have investigated protein sequence space, the extent of structural annotation, and the distribution of different domain architectures in completed genomes from all kingdoms of life. As with earlier studies by other researchers, the distribution of domain families shows power‐law behavior such that the largest 2,000 domain families can be mapped to ∼70% of nonsingleton genome sequences; the remaining sequences are assigned to much smaller families. While ∼50% of domain annotations within a genome are assigned to 219 universal domain families, a much smaller proportion (< 10%) of protein sequences are assigned to universal protein families. This supports the mosaic theory of evolution whereby domain duplication followed by domain shuffling gives rise to novel domain architectures that can expand the protein functional repertoire of an organism. Functional data (e.g. COG/KEGG/GO) integrated within Gene3D result in a comprehensive resource that is currently being used in structure genomics initiatives and can be accessed via http://www.biochem.ucl.ac.uk/bsm/cath/Gene3D/. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Structural and electrical properties of metal impurities at dislocations in silicon
Authors: Seibt M. , Kveder V. , Schröter W. , Voß O.
Published: March 2005

The electrical properties of silicon materials containing dislocations are strongly affected by deep levels at or close to the dislocation core. Such deep levels are frequently thought to be due to metal impurities that are chemically bound to the dislocation core, segregated in the long‐range strain field or precipitated at the dislocation. This paper summarizes recent experimental studies of the interaction of metal impurities with dislocations in silicon. Transmission electron microscopy and deep level transient spectroscopy are the main techniques to study precipitation at dislocations and binding or segregation of metal impurity atoms, respectively. Focus is drawn to precipitation of fast diffusing 3d transition metals where dislocations not only serve as nucleation sites but also establish fast growth kinetics. In addition, gold impurities in the strain field of dislocations give rise to an acceptor level with the capture kinetics of extended localized defects while the emission characteristics are hardly distinguished from those of the acceptor level of gold atoms in the undisturbed bulk. The results will be discussed in terms of possible response of the deep impurity level and the silicon bands to the dislocation strain field. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoreflectance on wide bandgap nitride semiconductors
Authors: Bru‐Chevallier C. , Fanget S. , Philippe A.
Published: March 2005

Extensive research has been reported on the wide band gap nitride materials system in the past few years. Despite the development of many well‐working GaN based opto‐ and electronic devices, theoretical and experimental understanding of many fundamental properties remains still incomplete.

In this paper, we show the unique benefits that can be drawn from optical modulation spectroscopy as applied to nitride materials, despite the difficulties in working in the UV spectral range, that is required for the photoreflectance measurements of wide band gap semiconductors.

By performing PR spectroscopy at low temperature in cubic phase GaN layers grown on c‐SiC pseudo‐substrates, the different valence band excitons are measured and compared with theoretical calculations, allowing the determination of residual strain inside the epitaxial layer. The second part of the paper is devoted to emphasize the unique interest of PR spectroscopy in the Franz Keldysh oscillations regime, especially in the case of wurtzite phase GaN/AlGaN quantum structures, in order to extract the piezoelectric field in a non‐destructive all‐optical experiment. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polarity determination of InN by wet etching
Authors: Muto Daisuke , Araki Tsutomu , Naoi Hiroyuki , Matsuda Fumie , Nanishi Yasushi
Published: March 2005

We have succeeded in distinguishing the polarities of InN by wet etching using KOH solution for the first time. We found N‐polar InN was etched roughly, and hexagonal pyramids surrounded by {10$\bar 1 \bar 1$} facets appeared after etching for 60 min. On the other hand, In‐polar InN was etched smoothly in shorter term of etching. These features observed are very similar to those reported for GaN. After longer term of exposure to the KOH solution over 60 min, however, hexagonal and dot type etch pits appeared on the surface of In‐polar InN. The densities of hexagonal and dot type etch pits were 3 ∼ 5 × 109 cm–2 and 1 ∼ 3 × 1010 cm–2, respectively. Since the densities of these etch pits almost correspond to the dislocation densities of InN, it is considered that the etch pit formation is related to the threading dislocations. In this study, it was also found for the first time that InN layers grown on (0001) sapphire substrates using a low‐temperature GaN buffer layer had In‐polarity. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High Body Mass Index as a Possible Risk Factor for Pilonidal Sinus Disease in Adolescents
Authors: Arda İrfan Serdar , Güney L. Hakan , Sevmiş Şinasi , Hiçsönmez Akgün
Published: March 2005

Pilonidal sinus disease (PSD) is common in adults, but it may also develop in adolescents. The intergluteal groove is a deep moist area in which broken hairs and foreign bodies can collect, often leading to infection. Only a few papers have been published considering PSD in children. For the present study, we retrospectively examined the data of operated patients with PSD. From that review, it appears that high body mass index (BMI) might be a risk factor for the development of PSD and its complications in older children. Fourteen young patients (12 males, 2 females, 12–18 years of age) underwent surgery for PSD. According to the BMI‐for‐age, eight of these patients (57, 1%) were overweight or obese. Five of them (35.8%) developed mild to moderate postoperative complications. Symptoms recurred in one patient (7.1%) whose BMI was considered as overweight. In patients with normal weight no early or late complications developed. Our findings suggest that high BMI in adolescents is a significant risk factor in the development of both symptoms and complications of PSD after surgical treatment.
Application of a sequential regime shift detection method to the Bering Sea ecosystem
Authors: Rodionov Sergei , Overland James E.
Published: March 2005

A common problem of existing methods for regime shift detection is their poor performance at the ends of time-series. Consequently, shifts in environmental and biological indices are usually detected long after their actual appearance. A recently introduced method based on sequential t-test analysis of regime shifts (STARS) treats all incoming data in real time, signals the possibility of a regime shift as soon as possible, then monitors how perception of the magnitude of the shift changes over time. Results of a STARS application to the eastern Bering Sea ecosystem show how the 1989 and 1998 regime shifts manifest themselves in biotic and abiotic indices in comparison with the 1977 shift.
The Objects of Ignatius' Wrath and Jewish Angelic Mediators
Authors: MARSHALL JOHN W.
Published: March 2005

Scholars continue to argue about whether Ignatius' epistles give evidence of one or two groups of opponents. It is the claim of this article that Ignatius confronted a single group. We will best understand the characteristics and heritage of its members first by taking care not to overemphasise the systematic character of their thinking about Jesus, and second by setting their Christology within the context of Jewish speculation about divine mediator figures and the varieties of ‘Christian’ beliefs about Jesus. The article also compares Ignatius' positions with characteristics of Jewish Christianity and suggests that the intensity of his polemic may owe more to what he shared with this group than to the differences between them. The article concludes with some observations about the difficulties inherent in the term ‘Jewish Christianity’.
The Renegotiation of the Social Pact in Hong Kong: Economic Globalisation, Socio-economic Change, and Local Politics
Authors: LEE ELIZA W. Y.
Published: March 2005

This article discusses the politics of social policy development in Hong Kong following the Asian financial crisis. It examines the cause, mode and political significance of social policy reform in an Asian late industrialiser that has been experiencing the twin pressures of economic globalisation and socio-economic change. Financial austerity has prompted the state to adopt social policy reforms through re-commodification and cost containment, resulting in the retrenchment of the residual welfare state. The state's policy choices are structured by local politics, including the state of political development and the path dependence nature of policy change. The article questions the effectiveness of the social authoritarian approaches adopted by the state in attempting to renegotiate the social pact with its citizens, and contends that progressive development in social policy is inevitably bound to democratisation.
Probabilistic modeling of tephra dispersal: Hazard assessment of a multiphase rhyolitic eruption at Tarawera, New Zealand
Authors: Bonadonna C. , Connor C. B. , Houghton B. F. , Connor L. , Byrne M. , Laing A. , Hincks T. K.
Published: March 2005

The Tarawera Volcanic Complex comprises 11 rhyolite domes formed during five major eruptions between 17,000 B.C. and A.D. 1886, the first four of which were predominantly rhyolitic. The only historical event erupted about 2 km3 of basaltic tephra fall (A.D. 1886). The youngest rhyolitic event erupted a tephra fall volume more than 2 times larger and covered a wider area northwest and southeast of the volcano (∼A.D. 1315 Kaharoa eruption). We have used the Kaharoa scenario to assess the tephra fall hazard from a future rhyolitic eruption at Tarawera of a similar scale. The Plinian phase of this eruption consisted of 11 discrete episodes of VEI 4. We have developed an advection‐diffusion model (TEPHRA) that allows for grain size‐dependent diffusion and particle density, a stratified atmosphere, particle diffusion time within the rising plume, and settling velocities that include Reynolds number variations along the particle fall. Simulations are run in parallel on multiple processors to allow a significant implementation of the physical model and a fully probabilistic analysis of inputs and outputs. TEPHRA is an example of a class of numerical models that take advantage of new computational tools to forecast hazards as conditional probabilities far in advance of future eruptions. Three different scenarios were investigated for a comprehensive tephra fall hazard assessment: upper limit scenario, eruption range scenario, and multiple eruption scenario. Hazard curves and probability maps show that the area east and northeast of Tarawera would be the most affected by a Kaharoa‐type eruption.
Reassessing landslide deformation in Ganges Chasma, Mars
Authors: Bulmer Mark H. , Zimmerman Brandy A.
Published: March 2005

High‐resolution images of landslide aprons in Ganges Chasma show extensive scarps, rock chutes, and talus accumulations on the canyon rim. Below these exists a topographic bench formed of multiple terraces, ridges and scarps. The terrace slopes are talus covered similar to the canyon rim. Small volume lobes and sheets originate from talus accumulations and extend downslope. While previously determined to be the result of large volume catastrophic landslides, the characteristics and dimensions of the terraces forming the topographic bench can be explained by deep‐seated gravitational creep of the ancient rock mass. Gravity driven movements over millions of years can also account for the morphology and dimensions of talus lobes thus offering an alternative to catastrophic long‐runout landslide mechanisms. The movement of lobes is suggested to be analogous to terrestrial periglacial rock glaciers.
Mass release at Jupiter: Substorm‐like processes in the Jovian magnetotail
Authors: Kronberg E. A. , Woch J. , Krupp N. , Lagg A. , Khurana K. K. , Glassmeier K.‐H.
Published: March 2005

The Jupiter orbiting spacecraft Galileo has provided evidence that the Jovian magnetotail is subject to a periodic process with typical timescales of several days by which the Jovian system is presumably releasing its excess iogenic mass. The mass release process resembles a terrestrial substorm in the sense of a global reconfiguration of the magnetotail. During the initial “loading” phase the plasma convection is at a moderate speed in the corotation direction and the Jovian plasma sheet appears to be in a stable configuration. In the release phase, reconnection through a thinned current sheet leads to radially inward and outward plasma flows and the ejection of plasmoids. Storage of magnetic energy in the lobe region seems not to be the prime driver of the reconfiguration process. Therefore the role of the solar wind as energy source is of less importance than for terrestrial substorms. Instead, it can be envisaged that plasma loading of fast rotating magnetic flux tubes and the associated centrifugal forces drive the reconfiguration process.
A springtime comparison of tropospheric ozone and transport pathways on the east and west coasts of the United States
Authors: Cooper O. R. , Stohl A. , Eckhardt S. , Parrish D. D. , Oltmans S. J. , Johnson B. J. , Nédélec P. , Schmidlin F. J. , Newchurch M. J. , Kondo Y. , Kita K.
Published: March 2005

We have conducted a study to determine the influence of Asian pollution plumes on free tropospheric ozone above the west coast of the United States during spring. We also explored the additional impact of North American emissions on east coast free tropospheric ozone. Long‐term ozone monitoring sites in the United States are few, but we obtained ozonesonde profiles from Trinidad Head on the west coast, Huntsville, Alabama, in the southeast, and Wallops Island, Virginia, on the east coast. Additional east coast ozone profiles were measured by the MOZAIC commercial aircraft at Boston, New York City, and Philadelphia. Kilometer‐averaged ozone was compared between Trinidad Head and the three east coast sites (MOZAIC, Wallops Island, and Huntsville). Only in the 0–1 km layer did the MOZAIC site have a statistically significant greater amount of ozone than Trinidad Head. Likewise only the 0–1 and 1–2 km layers had greater ozone at Wallops Island and Huntsville in comparison to Trinidad Head. While Wallops Island did show greater ozone than Trinidad Head at 6–9 km, this excess ozone was attributed to a dry air mass sampling bias. A particle dispersion model was used to determine the surface source regions for each case, and the amount of anthropogenic NOx tracer that would have been emitted into each air mass. Transport times were limited to 20 days to focus on the impact of direct transport of pollution plumes from the atmospheric boundary layer. As expected, the amount of NOx tracer emitted into the east coast profiles was much greater in the lower and mid troposphere than at the west coast. At various altitudes at both coasts there existed a significant positive correlation between ozone and the NOx tracer, but the explained variance was generally less than 30%. On the east coast, Wallops Island had the weakest relationship between ozone and the NOx tracer, while Huntsville had the strongest. During spring, differences in photochemistry and transport pathways in the lowest 2 km of the troposphere results in an extra 5–14 ppbv of ozone on the east coast in comparison to Trinidad Head. However, despite differing amounts of NOx tracer from Asia and North America in the free troposphere, we found no significant difference in free tropospheric ozone between the east and west coasts of the United States during spring.
Development and initial evaluation of a dynamic species‐resolved model for gas phase chemistry and size‐resolved gas/particle partitioning associated with secondary organic aerosol formation
Authors: Griffin Robert J. , Dabdub Donald , Seinfeld John H.
Published: March 2005

A module for predicting the dynamic evolution of the gas phase species and the aerosol size and composition distribution during formation of secondary organic aerosol (SOA) is presented. The module is based on the inorganic gas‐aerosol equilibrium model Simulating the Composition of Atmospheric Particles at Equilibrium 2 (SCAPE2) and updated versions of the lumped Caltech Atmospheric Chemistry Mechanism (CACM) and the Model to Predict the Multiphase Partitioning of Organics (MPMPO). The aerosol phase generally consists of an organic phase and an aqueous phase containing dissolved inorganic and organic components. Simulations are presented in which a single salt (either dry or aqueous), a volatile organic compound, and oxides of nitrogen undergo photo‐oxidation to form SOA. Predicted SOA mass yields for classes of aromatic and biogenic hydrocarbons exhibit the proper qualitative behavior when compared to laboratory chamber data. Inasmuch as it is currently not possible to represent explicitly aerosol phase chemistry involving condensed products of gas phase oxidation, the present model can be viewed as the most detailed SOA formation model available yet will undergo continued improvement in the future.
Spacecraft Doppler tracking: Noise budget and accuracy achievable in precision radio science observations
Authors: Asmar S. W. , Armstrong J. W. , Iess L. , Tortora P.
Published: March 2005

We discuss noise in Doppler tracking of deep space probes and provide a detailed noise model for Doppler radio science experiments. The most sensitive current experiments achieve fractional frequency fluctuation noise of about 3 × 10−15 at 1000‐s integration time, corresponding to better than 1 micron per second velocity noise. Our noise model focuses primarily on the Fourier range ≈10−4–1 Hz, but we briefly discuss noise in lower‐frequency observations. We indicate applications of the noise model to experiment planning, identify phenomena limiting current Doppler sensitivity, and discuss the prospects for significant sensitivity improvements.