bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and characterization of sulfonated poly(benzoxazole ether ketone)s by direct copolymerization as novel polymers for proton‐exchange membranes
Authors: Li Jinhuan , Yu Hongyan
Published: April 2007

A new series of sulfonated poly(benzoxazole ether ketone)s (SPAEKBO‐X) were prepared by the aromatic nucleophilic polycondensation of 4,4′‐(hexafluoroisopropylidene)‐diphenol with 2,2′‐bis[2‐(4‐fluorophenyl)benzoxazol‐6‐yl]hexafluoropropane and sodium 5,5′‐carbonylbis‐2‐fluorobenzenesulfonate in various ratios. Fourier transform infrared and 1H NMR were used to characterize the structures and sulfonic acid contents of the copolymers. The copolymers were soluble in N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide, and N,N‐dimethylformamide and could form tough and flexible membranes. The protonated membranes were thermally stable up to 320 °C in air. The water uptake, hydrolytic and oxidative stability, and mechanical properties were evaluated. At 30–90 °C and 95% relative humidity, the proton conductivities of the membranes increased with the sulfonic acid content and temperature and almost reached that of Nafion 112. At 90–130 °C, without external humidification, the conductivities increased with the temperature and benzoxazole content and reached above 10−2 S/cm. The SPAEKBO‐X membranes, especially those with high benzoxazole compositions, possessed a large amount of strongly bound water (>50%). The experimental results indicate that SPAEKBO‐X copolymers are promising for proton‐exchange membranes in fuel cells, and their properties might be tailored by the adjustment of the copolymer composition for low temperatures and high humidity or for high temperatures and low humidity; they are especially promising for high‐temperature applications. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2273–2286, 2007
Urodynamic changes in a noble rat model for nonbacterial prostatic inflammation
Authors: Bernoulli Jenni , Yatkin Emrah , Talvitie Eva‐Maria , Santti Risto , Streng Tomi
Published: April 2007

BACKGROUND

Chronic nonbacterial prostatitis (CP) associated with voiding dysfunction is a poorly understood clinical phenomenon. The goal of the present study was to induce prostatic inflammation with estrogen and androgen treatment and to record associated urodynamic changes in Noble rats.

METHODS

Rats were treated with estradiol and testosterone implants to increase estradiol concentration in serum while testosterone concentration was maintained at or slightly above the control level. The urodynamical recordings were performed under anesthesia after the hormone treatments for 3 and 6 weeks. The dorsolateral lobes of the prostates were removed for histopathological analysis after recordings.

RESULTS

After the 3‐week treatment, lymphocytes, mainly T‐cells, were located around the capillaries. During the following 3 weeks lymphocytes migrated into stroma and acini. Cytotoxic T‐cells were seen intraepithelially, and neutrophiles inside the acini. Removal of estrogen implant or treatment with anti‐estrogen diminished inflammation. No changes in voiding pattern were seen after the 3‐week treatment. Three weeks later, bladder weight and capacity were increased, and the micturition time was prolonged.

CONCLUSIONS

Elevated estrogen concentration was essential for the gradual development of prostatic inflammation. The profile and location of inflammatory cells suggest that prostatic vasculature is one of the sites of estrogen action. Urodynamic changes which developed in association with glandular inflammation indicated abnormal bladder function, reflecting an incipient obstruction. Prostate 67: 888–899, 2007. © 2007 Wiley‐Liss, Inc.
Lithium suppresses cell proliferation by interrupting E2F–DNA interaction and subsequently reducing S–phase gene expression in prostate cancer
Authors: Sun Aijing , Shanmugam Ilanchezian , Song Jiawu , Terranova Paul F. , Thrasher J. Brantley , Li Benyi
Published: April 2007

BACKGROUND

Lithium is an existing drug for bipolar disorder and its uptake was recently linked to reduced tumor incidence compared to the general population. The major target of lithium action is glycogen synthase kinase 3 (GSK‐3). Since GSK‐3 expression and activation are associated with prostate cancer progression, the anti‐cancer potential of lithium on prostate cancer was investigated in this study.

METHODS

Multiple prostate cancer cell lines were treated with lithium chloride (LiCl). Cell proliferation and cell cycle distribution were analysed. DNA replication was determined using BrdU labeling assay. Genome‐wide screening of gene expression was performed using cDNA microarray assay. GSK‐3β gene‐specific silencing was conducted using small interferencing RNA (siRNA) transfection. E2 factor (E2F) transactivation was evaluated using reporter gene assay and E2F–DNA interaction was determined with chromatin‐immunoprecipitation assay (ChIP).

RESULTS

LiCl significantly inhibited cell proliferation, which was associated with reduced DNA replication and S‐phase cell cycle arrest. LiCl significantly decreased the expression of multiple DNA replication‐related genes, including cell division cycle 6 (cdc6), cyclin A, cyclin E, and cdc25C, which are regulated by E2F factor during cell cycle. A novel GSK‐3‐specific inhibitor TDZD‐8 and GSK‐3β siRNA also suppressed the expression of these E2F target genes, indicating that LiCl‐induced anti‐cancer effect was associated with GSK‐3β inhibition. Furthermore, LiCl suppressed E2F transactivation by interrupting the interaction of E2F1 factor with its target gene promoter.

CONCLUSIONS

These data indicated that LiCl suppresses cancer cell proliferation by disrupting E2F–DNA interaction and subsequent E2F‐mediated gene expression in prostate cancer. Prostate 67: 976–988, 2007. © 2007 Wiley‐Liss, Inc.
Isolation and characterization of antimicrobial proteins and peptide from chicken liver
Authors: Li Guan‐Hong , Mine Yoshinori , Hincke Maxwell T. , Nys Yves
Published: April 2007

Endogenous antimicrobial peptides and proteins are crucial components of the innate immune system and play an essential role in the defense against infection. Antimicrobial activity was detected in the acid extract of livers harvested from healthy adult White Leghorn hens, Gallus gallus. Two antimicrobial proteins and one antimicrobial polypeptide were isolated from the liver extract by cation‐exchange and gel filtration chromatography, followed by two‐step reverse‐phase high‐performance liquid chromatography (RP‐HPLC). These antimicrobial components were identified as histones H2A and H2B.V, and histone H2B C‐terminal fragment using peptide mass fingerprinting and partial sequencing by tandem nanoelectrospray mass spectrometry. The proteins and the peptide identified in the present study, which exhibited antimicrobial activity against both Gram‐positive and Gram‐negative bacteria, were thermostable and showed salt‐resistant activity. The antimicrobial properties of histones and histone fragment in chicken provide further evidence that histones, in addition to their role in nucleosome formation, may play an important role in innate host defense against intracellular or extracellular microbe invasion in a wide range of animal species. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Current‐induced switching in spin‐valve structures
Authors: Barnaś J. , Gmitra M. , Misiorny M. , Dugaev V.
Published: April 2007

Spin transfer between conduction electrons and local magnetic moments can switch spin valves between different magnetic configurations. In some conditions, however, the spin torque can induce magnetic switching to stationary precessional modes. In this paper we consider current‐induced magnetic switching in nanopillar spin valves including two thin magnetic films separated by a nonmagnetic layer, and in molecular‐based spin valves. In the former case the spin torque is calculated from the macroscopic spin diffusion equations, while in the latter one we use quantum description based on the Fermi golden rule. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Semiconductor nanocrystals and embedded quantum dots: Electronic and optical properties
Authors: Schulz S. , Schumacher S. , Czycholl G.
Published: April 2007

A tight‐binding model for semiconductor quantum dots (QD) consisting of a small gap semiconductor material A embedded within a larger gap material B is used to determine the bound, localized one‐particle QD‐states. The form and symmetry properties of these states and their dependence on form, size and composition of the QDs are discussed. The Coulomb and dipole matrix elements between these states are calculated so that a many‐body Hamiltonian is derived describing the elctronic properties of the QDs and the coupling to an applied (optical) electric field. Truncating the many‐particle Hilbert space by taking into account only a finite number of localized electron and hole states the many‐body Hamiltonian can be solved exactly. The resulting excitation spectrum and optical properties are presented and discussed. The method is, in particular, applied to CdSe QDs embedded in ZnSe with zincblende structure, to CdSe nanocrystals, and to InN QDs embedded in GaN with wurtzite structure. For the latter case also the influence of an intrinsic piezoelectric field and of the special symmetry properties of the wurtzite structure are discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrospray ionization/atmospheric pressure photoionization multimode source for low‐flow liquid chromatography/mass spectrometric analysis
Authors: Short Luke C. , Hanold Karl A. , Cai Sheng‐Suan , Syage Jack A.
Published: April 2007

Analysis of several polar and non‐polar compounds is performed with a newly developed dual electrospray ionization/atmospheric pressure photoionization (ESI/APPI) or ESPI source. Several variables are considered in the source, such as ESI probe heater temperature, solvent flow, dopant effects, repeller plate voltage, source geometry and photon energy (Kr vs. Ar lamp). Direct photoionization resulting in a molecular radical cation [M].+ dominates at high temperatures (>400°C) and low flow rates (<200 µL/min). Indirect photo‐induced chemical ionization (PCI) involving solvent molecules becomes important at lower temperatures and higher solvent flow rates. Indirect PCI is enhanced using an Ar lamp, which yields comparable [M+H]+ signal but poorer [M].+ signal than the Kr lamp at lower temperatures and higher flow rates. This is in support of our recent finding that the Ar lamp results in a solvent‐dependent enhancement of analyte molecules via PCI. Analysis of 12 compounds in methanol under low‐flow conditions (10 µL/min) demonstrates that the dual ESPI source performs favorably for most compounds versus the standard ESCI source, and significantly better than ESCI for the analysis of unstable drugs, like flurbiprofen. Several factors contributing to the benefits of the ESPI source are the shared optimal geometry for ESI and APPI sources and soft ionization of APPI versus APCI. Copyright © 2007 John Wiley & Sons, Ltd.
Fast and direct screening of polyaromatic hydrocarbon (PAH)‐contaminated sand using a miniaturized membrane inlet mass spectrometer (mini‐MIMS)
Authors: Frandsen Helle , Janfelt Christian , Lauritsen Frants R.
Published: April 2007

A miniaturized membrane inlet mass spectrometer (mini‐MIMS; total weight 10 kg everything included) was equipped with a small sample cell using a flat sheet silicone membrane mounted close to the ionizing region of a multipole mass spectrometer. Spiked sand samples were placed in small stainless steel vials and dropped into the heated sample cell (>150°C). A hole in the vial in front of the membrane and above the sand made it possible for the polyaromatic hydrocarbon (PAH) residuals to penetrate the membrane and enter the mass spectrometer as they evaporated from the sample. Using this simple setup we were able to quantitatively (≈10% relative standard deviation (RSD)) detect PAHs with up to five aromatic rings and with detection limits in the low parts‐per‐million (ppm) range. The vial system solves one of the major difficulties in analysis of larger PAHs using a MIMS. Normally, analysis of PAHs with more than two rings is hampered by a long memory effect due to the sticking of the PAHs to the inlet system, the membrane and surfaces in the vacuum system. By removing the vial from the sample cell within 2 min, we were able to analyze samples at 5–10 min intervals. The preliminary laboratory experiments presented here show much promise with respect to the development of a hand held (<10 kg) on‐site mass spectrometry system for PAH screening at contaminated sites. Copyright © 2007 John Wiley & Sons, Ltd.
Study on ion formation in electrospray droplet impact secondary ion mass spectrometry
Authors: Asakawa Daiki , Fujimaki Susumu , Hashimoto Yutaka , Mori Kunihiko , Hiraoka Kenzo
Published: April 2007

A new type of cluster secondary ion mass spectrometry (SIMS), named electrospray droplet impact (EDI), has been developed in our laboratory. In general, rather strong negative ions as well as positive ions can be generated by EDI compared with conventional SIMS. In this work, various aspects of ion formation in EDI are investigated. The Brønsted bases (proton acceptor) and acids (proton donor) mixed in the analyte samples enhanced the signal intensities of deprotonated molecules (negative ions) and protonated molecules (positive ions), respectively, for analytes. This suggests the occurrence of heterogeneous proton transfer reactions (i.e. M + M′ → [M+H]+ + [M′H]−) in the shockwave‐heated selvedge of the colliding interface between the water droplet and the solid sample deposited on the metal substrate. EDI‐SIMS shows a remarkable tolerance to the large excess of salts present in samples. The mechanism for desorption/ionization in EDI is much simpler than those for MALDI and SIMS because only very thin sample layers take part in the shockwave‐heated selvedge and complicated higher‐order reactions are largely suppressed. Copyright © 2007 John Wiley & Sons, Ltd.
Academic and informal science education practitioner views about professional development in science education
Authors: Astor‐Jack Tamsin , McCallie Ellen , Balcerzak Phyllis
Published: April 2007

This study documents the views of effective professional development held by eight professional development (PD) providers, representing four informal science institutions (ISI) and four programs within two institutions of higher education (IHE) in a large midwestern metropolitan area in the United States. This study finds that, while the reported learning and outcome agendas of the providers were similar across the board, a dichotomy in approach to PD emerged according to the type of institution. This dichotomy between ISI and IHE was persistent across thematic categories: (1) language use and meaning, (2) teacher outcomes as a result of PD, (3) resource strengths for teaching and learning, and (4) determination of content and course offerings. The significance of this research is threefold. First, the identification and characterization of important features of teacher PD in ISI is an important contribution to the PD literature, since most previous studies focus on IHE. Second, this study elucidates important differences between the two types of providers with respect to their views of inquiry, currently a fundamental component of PD for science teachers. Third, previously unreported gaps and overlaps in belief systems of PD from two institutions types, ISI and IHE, are identified. © 2007 Wiley Periodicals, Inc. Sci Ed 91:604–628, 2007
Similarity of software system and its measurement tool SMMT
Authors: Yamamoto Tetsuo , Matsushita Makoto , Kamiya Toshihiro , Inoue Katsuro
Published: April 2007

Given two software systems, it is important to be able to objectively know how much those systems differ. However, it has not been easy to quantitatively measure the mutual differences between two systems. In this paper, the authors introduced similarity metrics for the similarity between software systems and the Similarity Metrics Measuring Tool (SMMT) for measuring them and applied SMMT to the source code of various UNIX‐type operating systems. They also performed a cluster analysis from the similarities of the source code of those operating systems to create a dendogram and checked whether the operating systems were classified correctly. The results confirmed that the similarity was an effective index for determining operating system transitions and that the family tree that was obtained represented the classification of the operating systems according to their derivations. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(6): 91–99, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10379
Signal processing for brain temperature change detection by noninvasive measurement: An independent component analysis approach
Authors: Wakuya Hiroshi , Yamashita Kazuo , Shida Katsunori
Published: April 2007

The distribution of temperature inside the brain is an important piece of information for investigating brain activity. Up to now, various kinds of noninvasive measurement techniques have been proposed. Among them, there is a technique that treats the human head as a dielectric material and then makes use of the temperature dependence of this material. One of its major problems is that accurate numerical measurements of the brain temperature might not be possible because the entire brain is surrounded by the skull, which has a relatively low permittivity. It has been reported that when blood flow stops due to brain death, the brain temperature changes in response to external temperature variations, and the response of the brain and skull are thought to differ. This paper focuses on this point in particular, and attempts to separate the brain and skull signals based on an independent component analysis (ICA) approach. In order to mimic this situation, a full human head model is constructed that incorporates the two components from the brain and skull, and the differences in the impedance per unit length in response to external variations in temperature are treated as the original signals. Two different electrode configurations that have different brain and skull component ratios are provided, and the total potential difference between the electrodes when they are connected to a constant current power source is measured. ICA is then applied to the two observed signals. The results reveal that although a problem arises whereby the amplitudes of the restored signals are attenuated compared to the original signals, the waveforms are exceptionally similar, demonstrating the validity of the proposed method. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(6): 80–90, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20232
A model of complex cell development by information separation
Authors: Date Akira , Kurata Koji
Published: April 2007

Neurons in the primary visual cortex (V1) of primates are selective for location, orientation, and spatial frequency. Among them, complex cells are characterized by their selectivity to orientation and spatial frequency while lacking sensitivity to position or phase tuning (dark/bright line center) within a restricted range. The development of the shift invariance property of complex cells has been successfully explained by the temporal trace learning which takes advantage of the temporal coherence of visual stimuli (P. Földiák, Neural Computation 1991;3:194). We have carried out mathematical modeling of complex cell development without temporal trace mechanism. The model network consists of three layers of E, S, and C layer which model excitatory cells in LGN or V1, and simple cells, and complex cells in V1, respectively. Neurons in layer E have position selectivity, and neurons in layer S are line detectors for a specific position. During the learning phase, the network is exposed to randomly located short oriented bars, and neurons in layer C self‐organize its selectivity to the inputs. The learning rules are Hebbian or SOM (self‐organizing map) type between layers S and C, and anti‐Hebbian between layers E and C by which neurons are forced to represent uncorrelated aspect of the inputs. We demonstrate that neurons in layer C learn invariance to shift in input position. Our model explains complex cell development in terms of the principle of information separation. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(7): 76– 83, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20483
Preparation for smooth pursuit eye movement based on expectation in humans
Authors: Tabata Hiromitsu , Miura Kenichiro , Kawano Kenji
Published: April 2007

It has been reported that a brief movement of a target during fixation elicited larger eye movement when primates were anticipating future smooth pursuit than when they were not, suggesting that the gain of visuomotor transmission was increased in association with the preparation for future tracking. Here, in order to investigate how the expectation for future tracking affects our preparation for smooth pursuit, we observed human eye movements elicited by a brief movement of a target when the probability to be required pursuit (target motion probability) was 0, 0.25, 0.5, 0.75, and 1. We found that the response to a brief target movement was continuously increased as the probability increased. This result suggests that the pursuit system determines the gain before the start of pursuit in accordance with the anticipated future need for tracking. We also showed that the relationship between the gain and the target motion probability could be derived from minimization of the trial‐by‐trial prediction error, suggesting that the preparatory gain was determined based on the least‐squares optimization. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(6): 1–9, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20677 Copyright © 2004 Wiley Periodicals, Inc.
A fast algorithm for hyperplane‐intersection method on image registration
Authors: Chang Soonkeun , Shimizu Masao , Okutomi Masatoshi
Published: April 2007

This study presents an alternative method to estimate the motion parameters for the gradient‐based method. The proposed method is a faster version of a hyperplane‐intersection method. The hyperplane‐intersection method estimates the motion parameters between images as an intersection position of estimated hyperplanes in a parameter space. The hyperplanes approximate the zero positions of the partial derivatives of a continuous similarity measure with respect to each parameter. The method employs a straightforward computation to estimate the parameters, instead of using an iterative framework. The non‐iterative method could be suitable for hardware implementation. The method is the region‐ and intensity‐based technique using any dissimilarity or similarity measure such as sum of squared differences (SSD) or zeromean normalized cross correlation (ZNCC), which can be selected adequately in consideration of a property of input image sequence and a required computation time. The faster version of the method is realized with precomputed warped images of the template, which reduce the computational cost for each input frame. This study also compares the computational cost and the accuracy of the estimated parameters of the proposed algorithm with the gradient descent method. Experiments using synthesized‐motion sequences and real image sequences are performed to confirm the comparisons. The SSD and ZNCC are used for the faster version of the hyperplane‐intersection method to overcome a nonuniform illumination change in the image sequences to demonstrate the effectiveness of the method. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(7): 23– 33, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20703
Analysis of a binary composite endpoint with missing data in components
Authors: Quan Hui , Zhang Daowen , Zhang Ji , Devlamynck Laure
Published: April 2007

Composite endpoints are often used in clinical trials in order to increase the overall event rates, reduce the sizes of the trials and achieve desired power. For example, in a trial to study the effect of a treatment on the prevention of venous thromboembolic events after a major orthopaedic surgery of the lower limbs, the primary endpoint is usually a composite endpoint consisting of any deep vein thrombosis identified by systematic venography of lower limbs, symptomatic and well‐documented non‐fatal pulmonary embolism, and death from all causes. Just as any endpoints, missing data can occur in the components of the composite endpoint. If a patient has missing data on some of the components but not all the components, this patient may not have complete data but partial data for the composite endpoint. To be consistent with the intention‐to‐treat
principle, the patient should not be discarded from the analysis. In this research, we propose an approach for the analysis of a composite endpoint with missing data in components. The main idea is to first derive the probabilities of all possible study outcomes based on the appropriate model and then to construct the overall rate for the composite endpoint. Simulations are conducted to compare the approach with several naïve methods. A data example is used to illustrate the application of the approach. Copyright © 2007 John Wiley & Sons, Ltd.
Islamic takaful: Business models, Shariah concerns, and proposed solutions
Authors: Wahab Abdul Rahim Abdul , Lewis Mervyn K. , Hassan M. Kabir
Published: April 2007

Islamic insurance (takaful) is nearly as old as the Islamic banking system and dates back to 1979, when the concept was launched in Sudan and later in Saudi Arabia. Yet, unlike its banking counterpart, takaful has been covered less in the literature on Islamic finance, and its workings are not fully understood. Shariah scholars have raised a num‐ber of concerns about the Shariah permissibility of the business models employed in the industry. This article examines the basic principles of takaful and then analyzes the mechanics of the two models most commonly used in the industry— namely, the mudarabah system that was developed by the Malaysians and the wakala (agency) system that is now being used by most takaful operators and has achieved tremendous popularity and acceptance in recent years even in countries where the mudarabah model was earlier implemented. Shariah scholars have, however, expressed some misgivings about both approaches, but because of its wider acceptability among Shariah scholars in the case of the wakala approach, this is more urgent. With regards to the mudarabah model for risk management, there are major discrepancies that have been highlighted by Shariah scholars effec‐tively rendering it inappropriate to apply this for insurance contracts. For this reason, the article outlines a third model, a wakala with waqf fund, that seeks to remain within the wakala framework while incorpo‐rating modifications that may render it more acceptable from a Shariah perspective. © 2007 Wiley Periodicals, Inc.
Two‐acceptor levels in the band gap of boron‐doped diamond semiconductors analyzed by soft x‐ray absorption spectroscopy and DV–Xα calculations
Authors: Muramatsu Yasuji , Takebe Toshihiko , Sawamura Akitaka , Iihara Junji , Nanba Akihiko , Imai Takahiro , Denlinger Jonathan D. , Perera Rupert C. C.
Published: April 2007

To clarify the electronic structure of semiconducting boron‐doped diamond, especially the two‐acceptor levels observed in the soft x‐ray absorption spectra in the C K region, the density of states (DOS) of a B‐doped diamond cluster model, BC146H148, were calculated using discrete variational (DV)‐Xα MO methods. The results were compared to the measured x‐ray spectra. In the calculations, the localized acceptor levels (lowest unoccupied molecular orbitals: (LUMOs)) appeared just above the highest occupied molecular orbitals (HOMOs) of the C atom that was directly bonded to the B atom, and the other C atoms that were bonded to the C atoms next to the B atom. However, a chemical shift of the LUMOs was not observed between the C atoms. On the other hand, a chemical shift of the occupied C 1s orbitals was observed between these C atoms. Therefore, it is concluded that the two‐acceptor levels in the C atoms result from the chemical shift of the inner C 1s orbitals due to the local structure differences between the C atoms in B‐doped diamond. Copyright © 2007 John Wiley & Sons, Ltd.
XANES analysis of Fe valence in iron gall inks
Authors: Arčon Iztok , Kolar Jana , Kodre Alojz , Hanžel Darko , Strlič Matija
Published: April 2007

In this study, we investigate the feasibility and reliability of Fe K‐edge XANES spectroscopy as a tool in determination of Fe2+/Fe3+ ratio in historic inks. We have measured Fe K‐edge XANES spectra of several historic and model iron gall inks with different Fe2+/Fe3+ ratios, together with some standard reference Fe2+ and Fe3+ compounds with known local atomic structure and symmetry around Fe atoms. We examine different approaches to determine relative amount of Fe2+ in iron gall inks from the Fe K‐edge shifts, and demonstrate that a proper choice of the Fe reference compounds with similar symmetry, same type of neighbour atoms in nearest coordination shells, arranged in a similar local structure is crucial for the absolute calibration of the Fe K‐edge shift and consequently a reliable determination of Fe2+/Fe3+ ratio in the sample. Best results, with the accuracy of ± 2%, are obtained by a linear combination fit with XANES spectrum of FeSO4· 7H2O as a reference for Fe2+ and spectrum of an iron gall ink containing predominantly Fe3+. Copyright © 2007 John Wiley & Sons, Ltd.
Dietary long‐chain polyunsaturated fatty acid supplementation in infants with phenylketonuria: a randomized controlled trial
Authors: Koletzko B. , Sauerwald T. , Demmelmair H. , Herzog M. , von Schenck U. , Böhles H. , Wendel U. , Seidel J.
Published: April 2007

Background

Pre‐ and postnatal tissue accretion of long‐chain polyunsaturated fatty acids (LCPUFA) has been related to visual and cognitive development in healthy children in several studies. Children with phenylketonuria (PKU) consume diets with very low contents of preformed LCPUFA. We studied prospectively the LCPUFA status in infants with PKU without or with LCPUFA supplementation during the first year of life.

Subjects and methods

Infants with PKU were enrolled at diagnosis (<4 weeks of age) and randomized double blind to phenylalanine‐free amino acid supplements without LCPUFA (n=11) or with both arachidonic (AA, 0.46 wt%) and docosahexaenoic acids (DHA, 0.27 wt%) (n=10). At enrolment and again at 1, 2, 3, 4, 6, 9 and 12 months, plasma phospholipid fatty acids were measured and dietary intakes were calculated from dietary protocols.

Results

Unsupplemented patients showed a marked LCPUFA depletion to levels clearly below those observed in healthy breast‐fed infants. In contrast, supplemented infants had stable and higher LCPUFA levels than unsupplemented infants, reaching significant differences for AA values at 3, 4 and 6 months, and for DHA values at 1, 3, 4, 6, 9 and 12 months. Plasma phospholipid levels correlated closely with estimated dietary intakes of preformed LCPUFA.

Conclusion

Low LCPUFA intakes with PKU diets induce marked depletion of AA and particularly of DHA in the first year of life. Thus endogenous synthesis of LCPUFA from precursors supplied by diet seems unable to compensate for low LCPUFA intakes. LCPUFA supplementation of PKU diets during the first year of life effectively enhances LCPUFA status to levels comparable to those of healthy breast‐fed infants.
Arginine 357 of SecY is needed for SecA‐dependent initiation of preprotein translocation
Authors: de Keyzer Jeanine , Regeling Anouk , Driessen Arnold J.M.
Published: April 2007

The Escherichia coli SecYEG complex forms a transmembrane channel for both protein export and membrane protein insertion. Secretory proteins and large periplasmic domains of membrane proteins require for translocation in addition the SecA ATPase. The conserved arginine 357 of SecY is essential for a yet unidentified step in the SecA catalytic cycle. To further dissect its role, we have analysed the requirement for R357 in membrane protein insertion. Although R357 substitutions abolish post‐translational translocation, they allow the translocation of periplasmic domains targeted co‐translationally by an N‐terminal transmembrane segment. We propose that R357 is essential for the initiation of SecA‐dependent translocation only.
Gene expression signatures in the newt irises during lens regeneration
Authors: Makarev Evgeny , Call Mindy K. , Grogg Matthew W. , Atkinson Donald L. , Milash Brett , Odelberg Shannon J. , Tsonis Panagiotis A.
Published: April 2007

Lens regeneration in adult newts is possible by transdifferentiation of the pigment epithelial cells (PECs) of the dorsal iris. The same cells in the ventral iris are not capable of such a process. To understand this difference in regenerative competency, we examined gene expression of 373 genes in the intact dorsal and ventral irises as well as in irises during the process of lens regeneration. We found similar signatures of gene expression in dorsal and ventral with several cases of even higher levels in the ventral iris. Such transcriptional activity in the regeneration‐incompetent ventral iris was unexpected and calls for a revision of our views about mechanisms of lens regeneration induction.
Stress‐induced rearrangements of cellular networks: Consequences for protection and drug design
Authors: Szalay Máté S. , Kovács István A. , Korcsmáros Tamás , Böde Csaba , Csermely Péter
Published: April 2007

The complexity of the cells can be described and understood by a number of networks such as protein–protein interaction, cytoskeletal, organelle, signalling, gene transcription and metabolic networks. All these networks are highly dynamic producing continuous rearrangements in their links, hubs, network‐skeleton and modules. Here we describe the adaptation of cellular networks after various forms of stress causing perturbations, congestions and network damage. Chronic stress decreases link‐density, decouples or even quarantines modules, and induces an increased competition between network hubs and bridges. Extremely long or strong stress may induce a topological phase transition in the respective cellular networks, which switches the cell to a completely different mode of cellular function. We summarize our initial knowledge on network restoration after stress including the role of molecular chaperones in this process. Finally, we discuss the implications of stress‐induced network rearrangements in diseases and ageing, and propose therapeutic approaches both to increase the robustness and help the repair of cellular networks.
Anion channels and transporters in plant cell membranes
Authors: de Angeli Alexis , Thomine Sébastien , Frachisse Jean-Marie , Ephritikhine Geneviève , Gambale Franco , Barbier-Brygoo Hélène
Published: April 2007

Anion channels/transporters appear as key players in signaling pathways leading to the adaptation of plant cells to abiotic and biotic environmental stresses, in the control of metabolism and in the maintenance of electrochemical gradients. Focusing on the most recent advances, this review aims at providing a description of the role of these channels in various physiological functions such as control of stomatal movements, plant–pathogen interaction, xylem loading, compartmentalization of metabolites and coupling with proton gradients. These functions have been demonstrated by a combination of electrophysiology, pharmacology and genetics approaches, the key issue being to identify the corresponding proteins and genes.
American Indian adolescent socialization: a review of the literature
Authors: Dinges Norman G. , Trimble Joseph E. , Hollenbeck Albert R.
Published: April 2007

This review presents a broad survey of American Indian adolescent socialization research beginning with early descriptive studies and progressing to current experimental investigations. Historical periods including the early years (1920–50) and the decades from 1950 to 1970 are reviewed for the goals, methods, results and criticisms related to the research conducted during these periods. Salient and broad ranging topics for future research are identified.
SOME PROPERTIES OF FREE GROUPS OF SOME SOLUBLE VARIETIES OF GROUPS
Authors: GROVES DANIEL
Published: April 2007

Let F be a free group, and let γn(F) be the nth term of
the lower central series of F. It is proved that
F/[γj(F), γi(F),
γk(F)] and F/[γj(F),
γi(F), γk(F),
γl(F)] are torsion free and residually nilpotent for certain
values of i, j, k and i, j, k, l, respectively.
In the process of proving this, it is proved that the analogous Lie rings are torsion free.
AUTOMORPHISMS OF RELATIVELY FREE GROUPS IN THE VARIETY N2A ∧
AN2 ∧ Nc
Authors: PAPISTAS ATHANASSIOS I.
Published: April 2007

For positive integers n and c, with n [ges ] 2, let
Gn, c be a relatively free group of finite rank n in the variety
N2A ∧ AN2 ∧ Nc.
It is shown that the subgroup of the automorphism group Aut(Gn, c) of
Gn, c generated by the tame automorphisms and an explicitly described finite set of
IA-automorphisms of Gn, c has finite index in
Aut(Gn, c). Furthermore, it is proved that there are no non-trivial elements of
Gn, c fixed by every tame automorphism of
Gn, c.
THE VERLINDE FORMULA FOR PARABOLIC BUNDLES
Authors: JEFFREY LISA C.
Published: April 2007

Let Σg be a compact Riemann surface of genus g, and
G = SU(n). The central element c =
diag(e2πid/n, …, e2πid/n)
for d coprime to n is introduced. The Verlinde formula is proved for the
Riemann–Roch number of a line bundle over the moduli space [Mscr ]g, 1(c, Λ)
of representations of the fundamental group of a Riemann surface of genus g with one boundary component, for
which the loop around the boundary is constrained to lie in the conjugacy class of
cexp(Λ) (for Λ ∈ t+), and also for the
moduli space [Mscr ]g, b(c, Λ) of representations
of the fundamental group of a Riemann surface of genus g with
s + 1 boundary components for which the loop around the 0th boundary component is sent to the central
element c and the loop around the jth boundary component is constrained to lie in the conjugacy class of
exp(Λ(j)) for Λ(j) ∈ t+.
The proof is valid for Λ(j) in suitable neighbourhoods of 0.
5-TORSION POINTS ON CURVES OF GENUS 2
Authors: BOXALL JOHN , GRANT DAVID , LEPRÉVOST FRANCK
Published: April 2007

Let C be a smooth proper curve of genus 2 over an algebraically closed field k.
Fix a Weierstrass point ∞in C(k) and identify C with its image in its Jacobian J under
the Albanese embedding that uses ∞ as base point. For any integer N[ges ]1, we write
JN for the group of points in J(k) of order dividing N and J*N for the subset of JN of
points of order N. It follows from the Riemann–Roch theorem that C(k)∩J2
consists of the Weierstrass points of C and that C(k)∩J*3 and C(k)∩J* are empty (see [3]). The purpose of this paper is to study curves C with C(k)∩J*5 non-empty.
NON-COMMUTATIVE CHARACTERISTIC POLYNOMIALS AND COHN LOCALIZATION
Authors: SHEIHAM DESMOND
Published: April 2007

Almkvist proved that for a commutative ring A the characteristic polynomial of an endomorphism α : P → P of a finitely generated projective A-module determines (P, α) up to extensions. For a
non-commutative ring A the generalized characteristic polynomial of an endomorphism of an endomorphism α : P → P of a finitely generated projective A-module is defined to be the Whitehead torsion [1 − xα] ∈ K1(A[[x]]), which is an equivalence
class of formal power series with constant coefficient 1.

The paper gives an example of a non-commutative ring A and an endomorphism α : P → P for which the
generalized characteristic polynomial does not determine (P, α) up to extensions. The
phenomenon is traced back to the non-injectivity of the natural map [sum ]−1A[x] → A[[x]] where [sum ]−1A[x] is the Cohn localization of A[x] inverting the set [sum ] of matrices in A[x] sent to an invertible matrix by A[x] → A;x [map ] 0.
Evolutionary diversity in polystomatids infecting tetraploid and octoploid Xenopus in East African highlands: biological and molecular evidence
Authors: JACKSON J. A. , TINSLEY R. C.
Published: April 2007

Species of Protopolystoma are monogenean flukes that only infect allopolyploid hosts in the anuran genus Xenopus. Multivariate analyses of morphometric sclerite characters in the nominal species Protopolystoma simplicis suggest that morphologically distinguishable populations occur in the tetraploid host, Xenopus laevis victorianus, and in each of the octoploid hosts, X. vestitus and X. wittei. The species-level divergence of a lineage specific to X. laevis is supported by sequence variation in the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. Protopolystoma simplicis from X. laevis is redesignated P. microsclera n. sp., with P. simplicis being retained for populations in octoploid hosts. This division is consistent with large differences in egg hatching schedule, fixed differences at the mannose-6-phosphate isomerase and fumarate hydratase loci, and host-specificity in experimental analyses. Although the respective P. simplicis populations in X. vestitus and X. wittei also show significant diversity in allozyme expression, morphometrics and egg hatching schedule, they are retained in the same species because their level of mitochondrial DNA divergence is similar to that found within other Protopolystoma species. The consequences of splitting P. simplicis for a recent interpretation of the origin of Protopolystoma faunas in octoploid Xenopus spp. is discussed.
Endocannabinoid signaling regulates spontaneous transmitter release from embryonic retinal amacrine cells
Authors: WARRIER AJITHKUMAR , WILSON MARTIN
Published: April 2007

GABAergic amacrine cells, cultured from embryonic chick retina, display spontaneous mini frequencies ranging from 0–4.6 Hz as a result of the release of quanta of transmitter from both synapses and autapses. We show here that at least part of this variation originates from differences in the degree to which endocannabinoids, endogenously generated within the culture, are present at terminals presynaptic to individual cells. Though all cells examined scored positive for cannabinoid receptor type I (CB1R), only those showing a low initial rate of spontaneous minis responded to CB1R agonists with an increase in mini frequency, caused by a Gi/o-mediated reduction in [cAMP]. Cells displaying a high initial rate of spontaneous minis, on the other hand, were unaffected by CB1R agonists, but they did show a rate decrease with CB1R antagonists. Such a regulation of spontaneous transmitter release by endocannabinoids might be important in network maintenance in amacrine cells and other inhibitory interneurons.
“Mehr Dinge zur gleichen Zeit“
Authors: Jäckel Michael , Wollscheid Sabine
Published: April 2007

Zusammenfassung. Insbesondere im Kontext der Nutzung ‘klassischer‘ Massenmedien sowie der Internetnutzung erfährt die adäquate Messung simultaner Aktivitäten neue Aufmerksamkeit. Unterschiedliche Methoden der Erfassung von Nebenbeiaktivitäten im Bereich der Fernsehnutzung werden in diesem Beitrag gegenübergestellt und hinsichtlich ihrer Zielsetzungen und Qualität diskutiert. Formen der Tagebuchmethode und der aktivitätsorientierten Befragung werden miteinander verglichen. Im Zentrum steht die Frage, ob eine adäquate Erfassung des Nebenbei-Fernsehens überhaupt mit herkömmlichen Befragungsmethoden erreicht werden kann, die bei den Teilnehmer/inne/n eine möglichst hohe Aufmerksamkeit während der Dokumentation voraussetzen. Es kann gezeigt werden, dass mit unterschiedlichen Formen der Tagebuchmethode sowie der aktivitätsorientierten Befragung annähernd gleiche Ergebnisse erzielt werden, was die Dauer des Nebenbei-Fernsehens betrifft. Auf dieser Grundlage lassen sich allerdings kaum Aussagen zu Rezeptions-Qualitäten treffen, was den zusätzlichen Einsatz qualitativer Methoden erforderlich macht.
Adjoint inverse modeling of dust emission and transport over East Asia
Authors: Yumimoto K. , Uno I. , Sugimoto N. , Shimizu A. , Satake S.
Published: April 2007

A four‐dimensional variational (4DVAR) data assimilation system was developed for a regional dust model. This report presents results of the first adjoint inversion of Asian dust emissions over East Asia using NIES LIDAR observations, targeting the extreme dust phenomenon on 30 April 2005. Optimized dust emissions mitigated underestimation of dust concentrations and brought the structure of the elevated dust layer (both onset timing and extinction coefficient intensity) into better agreement with LIDAR observations. We obtained a 31% (3.2 Tg) increase of calculated dust emissions through data assimilation, especially over the Mongolian region. The assimilated results agree with the TOMS AI distribution and indicate that the 4DVAR method is very powerful for unification of observation and numerical modeling. The method provides better estimation capability.
Timescales for radiation belt electron acceleration and loss due to resonant wave‐particle interactions: 1. Theory
Authors: Summers Danny , Ni Binbin , Meredith Nigel P.
Published: April 2007

Radiation belt electrons can interact with various modes of plasma wave in their drift orbits about the Earth, including whistler‐mode chorus outside the plasmasphere, and both whistler‐mode hiss and electromagnetic ion cyclotron waves inside the plasmasphere. Electrons undergo gyroresonant diffusion in their interactions with these waves. To determine the timescales for electron momentum diffusion and pitch angle diffusion, we develop bounce‐averaged quasi‐linear resonant diffusion coefficients for field‐aligned electromagnetic waves in a hydrogen or multi‐ion (H+, He+, O+) plasma. We assume that the Earth's magnetic field is dipolar and that the wave frequency spectrum is Gaussian. Evaluation of the diffusion coefficients requires the solution of a sixth‐order polynomial equation for the resonant wave frequencies in the case of a multi‐ion (H+, He+, O+) plasma, compared to the solution of a fourth‐order polynomial equation for a hydrogen plasma. In some cases, diffusion coefficients for field‐aligned waves can provide a valuable approximation for diffusion rates for oblique waves calculated using higher‐order resonances. Bounce‐averaged diffusion coefficients for field‐aligned waves can be evaluated generally in minimal CPU time and can therefore be profitably incorporated into comprehensive kinetic radiation belt codes.