bluuebunny/crossref_metadata_2025 huggingface dataset:
Decomposed direct matrix inversion for fast non‐cartesian SENSE reconstructions
Authors: Qian Yongxian , Zhang Zhenghui , Wang Yi , Boada Fernando E.
Published: June 2006

A new k‐space direct matrix inversion (DMI) method is proposed here to accelerate non‐Cartesian SENSE reconstructions. In this method a global k‐space matrix equation is established on basic MRI principles, and the inverse of the global encoding matrix is found from a set of local matrix equations by taking advantage of the small extension of k‐space coil maps. The DMI algorithm's efficiency is achieved by reloading the precalculated global inverse when the coil maps and trajectories remain unchanged, such as in dynamic studies. Phantom and human subject experiments were performed on a 1.5T scanner with a standard four‐channel phased‐array cardiac coil. Interleaved spiral trajectories were used to collect fully sampled and undersampled 3D raw data. The equivalence of the global k‐space matrix equation to its image‐space version, was verified via conjugate gradient (CG) iterative algorithms on a 2× undersampled phantom and numerical‐model data sets. When applied to the 2× undersampled phantom and human‐subject raw data, the decomposed DMI method produced images with small errors (≤3.9%) relative to the reference images obtained from the fully‐sampled data, at a rate of 2 s per slice (excluding 4 min for precalculating the global inverse at an image size of 256 × 256). The DMI method may be useful for noise evaluations in parallel coil designs, dynamic MRI, and 3D sodium MRI with fixed coils and trajectories. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Preparation and applications of novel amphiphilic fluoroalkyl end‐capped oligomers‐clay nanocomposites
Authors: Sawada Hideo , Takebayashi Airi , Uejima Mitsugu , Murakami Toshihide
Published: June 2006

Nonionic‐type amphiphilic fluoroalkyl end‐capped acryloylmorpholine and N,N‐dimethylacrylamide homooligomers were found to be new convenient intercalating agents for the achievement of an enlarged basal spacing of the clay layers to afford fluorinated oligomers‐clay nanocomposites. These novel fluoroalkyl end‐capped oligomers‐clay nanocomposites were found to exhibit good dispersibility and stability in aqueous and organic media, and were applied to the surface modification of traditional organic polymeric materials such as poly(methyl methacrylate). Copyright © 2006 John Wiley & Sons, Ltd.
Die Geschichte der Diuretika: Vom Coffein zum Furosemid
Authors: Rau Silvia
Published: June 2006

Die Entdeckungsgeschichte der Diuretika ist überwiegend von glücklichen Zufällen geprägt. Aus chemisch sehr unterschiedlichen Stoffen, den Purinen, den Quecksilberverbindungen und den Sulfonamiden, deren diuretische Wirkung mehr zufällig entdeckt und zunächst nur als eine Nebenwirkung bei anderweitiger Indikation betrachtet wurde, konnte die Forschung eine Arzneimittelgruppe entwickeln, deren hoher therapeutischer Stellenwert bis heute unbestritten ist.
Pathogenität des Vogelgrippe‐Virus H5N1
Authors: Winckler Thomas
Published: June 2006

Neue Studien beleuchten ein bislang wenig beachtetes Protein von Influenza‐Viren, das aber erheblich zur Pathogenität des Virus beizutragen scheint.
Influence of melt‐blending conditions on structural, rheological, and interfacial properties of polyamide‐12 layered silicate nanocomposites
Authors: Médéric Pascal , Razafinimaro Tolotrahasina , Aubry Thierry
Published: June 2006

The influence of the melt‐blending conditions on the structural, rheological, and interfacial properties of modified montmorillonite/Polyamide‐12 nanocomposites has been studied performing transmission electron microscopy observation combined with X‐Ray diffraction and rheological experiments. In the dilute regime, for short mixing times, the apparent aspect ratio of primary clay entities, determined from intrinsic viscosity measurements, is shown to increase with rotational speed. At high blade rotational speeds, the viscometric results suggest an almost achieved exfoliation, as confirmed by transmission electron microscopy micrographs. For longer mixing times, a significant drop of viscous dissipation is observed, which is very marked at high blade rotational speeds and attributed to a modification of the particle/matrix interface. In the concentrated regime, the rheological behavior of nanocomposites is attributed to the formation of a network of mesoscopic domains, composed of correlated clay entities. Upon increasing strain during mixing, the clay aggregates within these domains break into intercalated stacks and finally exfoliated layers, as shown by transmission electron microscopy micrographs and wide‐angle X‐ray diffraction patterns. The melt state elastic and viscous properties of the nanocomposites are mainly governed by the networked domains, and not by the nature and properties of the structure within the domains. POLYM. ENG. SCI. 46:986–994, 2006. © 2006 Society of Plastics Engineers.
Myosin binding protein C is differentially phosphorylated upon myocardial stunning in canine and rat hearts — Evidence for novel phosphorylation sites
Authors: Yuan Chao , Guo Yurong , Ravi Rajashree , Przyklenk Karin , Shilkofski Nicole , Diez Roberto , Cole Robert N. , Murphy Anne M.
Published: June 2006

Myocardial stunning is the transient cardiac dysfunction that follows brief episodes of ischemia and reperfusion without associated myocardial necrosis. Currently, there is limited knowledge about its cellular and biochemical mechanisms. In order to better understand the underlying mechanisms of contractile dysfunction associated with the stunning, comprehensive proteomic studies using 2‐D DIGE were performed using a regional stunning model in canine heart. Cardiac myosin binding protein C (cMyBP‐C), a regulatory myofilament protein associated with the thick filament, and nebulette, a thin filament associated protein, were differentially expressed. Phosphoprotein specific staining indicated both protein changes were due to phosphorylation. Subsequent phosphorylation mapping of canine cMyBP‐C using IMAC and MS/MS identified five phosphorylation sites, including three novel sites. In order to further evaluate this finding in a different model, cMyBP‐C phosphorylation was examined in a rat model of global stunning. In the rat model, stunning was associated with increased phosphorylation of cMyBP‐C at a critical calcium/calmodulin‐dependent kinase II site, and the increased phosphorylation was largely inhibited when stunning was prevented by either ischemic preconditioning or reperfusion in the presence of low‐calcium buffer. These data indicate cMyBP‐C phosphorylation plays an important role in myocardial stunning.
Cystic fibrosis enters the proteomics scene: New answers to old questions
Authors: Ollero Mario , Brouillard Franck , Edelman Aleksander
Published: June 2006

The discovery in 1989 of the gene encoding for the cystic fibrosis transmembrane conductance regulator (CFTR) and its mutation as the primary cause of cystic fibrosis (CF), generated an optimistic reaction with respect to the development of potential therapies. This extraordinary milestone, however, represented only the initial key step in a long path. Many of the mechanisms that govern the pathogenesis of CF, the most commonly inherited lethal pulmonary disorder in Caucasians, remain even today unknown. As a continuation to genomic research, proteomics now offers the unique advantage to examine global alterations in the protein expression patterns of CF cells and tissues. The systematic use of this approach will probably provide new insights into the cellular mechanisms involved in CF dysfunctions, and should ultimately result in the finding of new prognostic markers, and in the generation of new therapies. In this article we review the current status of proteomic research applied to the study of CF, including CFTR‐related interactomics, and evaluate the potential of these technologies for future investigations.
Mass spectrometry‐based proteomics for the detection of plant pathogens
Authors: Padliya Neerav D. , Cooper Bret
Published: June 2006

Plant diseases caused by fungi, oomycetes, viruses, and bacteria are devastating both to the economy and to the food supply of a nation. Therefore, the development of new, rapid methods to identify these pathogens is a highly important area of research that is of international concern. MS‐based proteomics has become a powerful and increasingly popular approach to not only identify these pathogens, but also to better understand their biology. However, there is a distinction between identifying a pathogen protein and identifying a pathogen based upon the detection of one of its proteins and this must be considered before the general application of MS for plant pathogen detection is made. There has been a recent push in the proteomics community to make data from large‐scale proteomics experiments publicly available in the form of a centralized repository. Such a resource could enable the use of MS as a universal plant pathogen detection technology.
IR spectroscopic strategies for the structural characterization of isolated and microsolvated arenium ions
Authors: Dopfer Otto
Published: June 2006

This contribution summarizes recent experimental developments in coupling modern sensitive IR spectroscopic techniques with selective mass spectrometric methods, which have allowed for the first time for the unambiguous structural characterization of isolated and microsolvated protonated aromatic molecules in the gas phase. The two major experimental strategies involve (i) single‐photon IR photodissociation (IRPD) spectroscopy in atandem quadrupole mass spectrometer using novel optical parametric oscillator (OPO) laser systems in the 2500–4000 cm−1 range and (ii) IR multiphoton dissociation (IRMPD) spectroscopy in a Fourier transform ion cyclotron resonance (FT‐ICR) mass spectrometer using high‐intensity free electron lasers (FEL) in the 500–2500 cm−1 range. Both techniques offer complementary spectroscopic information, which is highlighted for the various isomers of protonated fluorobenzene, a simple prototype for protonated aromatic molecules. The analysis of the IR spectra provides unprecedented experimental insight into structure, energetics, and chemical reactivity of these fundamental reactive intermediates under isolated and controlled microsolvation conditions. Copyright © 2006 John Wiley & Sons, Ltd.
Hydrogen bonding and rate enhancement in the photoinduced polymerization of telechelic urethane methacrylates based on a cycloaliphatic system: Tricyclodecane dimethanol
Authors: Deepak V. D. , Rajan J. , Asha S. K.
Published: June 2006

A new class of telechelic urethane methacrylic crosslinkers, based on a cycloaliphatic system (tricyclodecane dimethanol and tricyclodecane monomethanol), was synthesized. The synthesis was achieved by a two‐step condensation of 1,6‐hexamethylene diisocyanate or isophorone diisocyanate with tricyclodecane dimethanol and capping with hydroxyethyl methacrylate. Samples of hexanediol diacrylate, tricyclodecane monomethacrylate, and tricyclodecane dimethacrylate were used as non‐hydrogen‐bonding monomers for comparative studies of the curing kinetics. The photopolymerization of these telechelic systems was investigated with UV irradiation in the presence of 2,2‐diethoxy acetophenone as the photoinitiator, and the kinetics were followed by the monitoring of the double‐bond conversion at 815 cm−1 with Fourier transform infrared spectroscopy. The hydrogen‐bonded crosslinkers had higher double‐bond conversions than their non‐hydrogen‐bonded counterparts under identical conditions. The higher cure rate could be explained by hydrogen‐bonding preassociation in these systems, which brought the methacrylate double bonds within close proximity. The temperature effects on the hydrogen bonding were also investigated. A decrease in the extent of the double‐bond conversion with increasing temperature was observed for the hydrogen‐bonded crosslinker, in contrast to an increased conversion with temperature for hexanediol diacrylate and tricyclodecane dimethacrylate. This was directly indicative of a reduction of hydrogen bonding at elevated temperatures leading to lower conversions. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4384–4395, 2006
Synthesis of well‐defined, brush‐type, amphiphilic [poly(styrene‐co‐2‐hydroxyethyl methacrylate)‐graft‐poly(ε‐caprolactone)]‐b‐poly(ethylene oxide)‐b‐[poly(styrene‐co‐2‐hydroxyethyl methacrylate)‐graft‐poly(ε‐caprolactone)] and its aggregation behavior inaqueous media
Authors: Xu Xuewei , Jia Zhongfan , Sun Ruiming , Huang Junlian
Published: June 2006

Brush‐type, amphiphilic [poly(styrene‐co‐2‐hydroxyethyl methacrylate)‐graft‐poly(ε‐caprolactone)]‐b‐poly(ethylene oxide)‐b‐[poly(styrene‐co‐2‐hydroxyethylmethacrylate)‐graft‐poly(ε‐caprolactone)] was successfully synthesized via consecutive ring‐opening anionic polymerization, reversible addition–fragmentation chain transfer (RAFT) polymerization, and coordination–insertion ring‐opening polymerization (ROP). Two poly (ethylene oxide) macro‐RAFT agents with two 3‐benzylsulfanylthiocarbonylsufanyl propionic acid end groups were prepared by the reaction of Poly(ethylene oxide) with hydroxyl group at two ends [HO–PEO–OH] with 3‐benzylsulfanylthiocarbonylsufanyl propionic acid chloride in the presence of pyridine; their molecular weights were 4840 and 8570 g/mol, and their molecular weight distributions were 1.07 and 1.09, respectively. The obtained macro‐RAFT agents were used to mediate the copolymerization of styrene and 2‐hydroxyethyl methacrylate with 2,2‐azobisisobutyronitrile as the initiator and dimethylformamide as the solvent. The hydroxyl groups of the 2‐hydroxyethyl methacrylate units of the resulting triblock copolymers then initiated the ROP of ε‐caprolactone in the presence of Sn(Oct)2 at 100 °C in toluene. It was determined that the RAFT process was controllable. The self‐assembled morphologies of the copolymers varied from rods to pearl necklaces and vesicles with an increase in the water concentration in tetrahydrofuran from 22.0 to 25.7, 29.6, and 39.0%, and the morphologies were also dependent on the molecular weight and chain structure of the copolymers. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4396–4408, 2006
An Azido Ester Plasticizer, 1,3‐Di(Azidoacetoxy)‐2,2‐Di(Azidomethyl)Propane (PEAA): Synthesis, Characterization and Thermal Properties
Authors: Shaojun Qiu , Huiqing Fan , Chao Gao , Xiaodong Zheng , Xiaoxian Gan
Published: June 2006

A polyazido compound, 1,3‐di(azidoacetoxy)‐2,2‐di(azidomethyl)propane (PEAA) was synthesized and identified. Thermal properties of PEAA, such as the glass transition temperature (Tg), differential scanning calorimetry (DSC) and thermogravimetric analysis (DTG) were investigated in detail. Two steps in the course of thermal decomposition of PEAA were observed clearly, and some gases, carbon monoxide, carbon dioxide, nitrogen, hydrocyanic acid, methane and 2‐methyl‐1,3‐butadiene were identified as decomposition products by in situ cell FTIR. The pyrolysis mechanism was also proposed.
Reproductive success of bromadiolone‐resistant rats in absence of anticoagulant pressure
Authors: Heiberg Ann‐Charlotte , Leirs Herwig , Siegismund Hans R
Published: June 2006

Resistance to anticoagulant rodenticides in brown rats (Rattus norvegicus Berk.) is associated with pleiotropic effects, notably with an increased dietary vitamin K requirement. Owing to this disadvantage, resistance is believed to be selected against if anticoagulant selection is absent. In small experimental populations of wild brown rats, an investigation was carried out to establish whether tolerance to anticoagulant exposure changed over a period of 2 years. In the same populations, DNA microsatellite markers were used to infer parentage, and this made it possible to estimate reproductive success of sensitive and resistant rats and estimate effective population size, Ne. Even though there was evidence for a selection against resistant rats with high vitamin K requirement, anticoagulant tolerance was not seen to be significantly influenced in the absence of bromadiolone selection. As the population size under investigation was small, random genetic drift may have played a role in this. In the presence of bromadiolone selection, however, the tolerance was significantly increased, suggesting that continuous selection will increase the proportion of highly resistant rats in the population. It was found that, for both males and females, surprisingly few individuals contributed to the next generation with numerous offspring, and most breeders contributed with none or a single offspring. The expected higher reproductive success and consequent increase in proportional numbers of sensitive rats in the absence of anticoagulant selection could not be observed. Among the resistant rats, moderately resistant females were found to be better breeders than highly resistant breeders, but for resistant males the reverse was true. This could be explained by the fact that the increased vitamin K requirement results in sex differential selection; in highly resistant males the selection presumably takes place at the immature stage, whereas in females the vitamin K requirement becomes crucial at the reproductive stage, as vitamin K is not only essential for the blood clotting process but also for bone formation. Copyright © 2006 Society of Chemical Industry
Theoretical and experimental study of aparisthman: A natural product with anti‐ulcer activity
Authors: Brasil D. S. B. , Moreira R. Y. O. , Müller A. H. , Alves C. N.
Published: June 2006

Aparisthman is a furan diterpenoid with a clerodane skeleton isolated from Aparisthmium cordatum (Juss.) Bail. (Euphorbiaceae). This natural product presents significant anti‐ulcer activity to the level of cimetidine (Tagamet®), a compound used for the treatment of ulcers provoked by stress. The structure of X‐ray diffraction of the aparisthman was compared with theoretical calculations and the results showed that the theory is in accordance with the experimental data. The infrared (IR) and nuclear magnetic resonance (NMR) spectra also were obtained and compared with theoretical calculations. The B3LYP theory level, with the 6‐31G(d,p) basis set, leads the value to the IR absorption close to the value experimentally observed. NMR theoretical obtained with HF/6‐311+G(2d,p) shows little deviation of experimental results. Calculations of molecular electrostatic potential and stabilization energies suggest that the protonation of aparisthman will be able to occur on carbonyl oxygen atom (O4). © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Factors affecting technical success of fetal aortic valve dilation
Authors: Wilkins‐Haug L. E. , Tworetzky W. , Benson C. B. , Marshall A. C. , Jennings R. W. , Lock J. E.
Published: June 2006

Objective

We have reported previously that valve dilation enhances growth of cardiac structures and may prevent hypoplastic left heart syndrome (HLHS) in fetuses with critical aortic stenosis. We aimed to investigate maternal/fetal factors which may affect the technical success of fetal valvuloplasty, and to describe perinatal complications of the procedure.

Methods

This was a descriptive series of 22 fetuses diagnosed with critical aortic stenosis developing into HLHS which underwent intervention by valvuloplasty. Initially this was attempted using a percutaneous approach; reassessment after our first five attempts, only one of which was successful, led to the introduction of the option of laparotomy. Technical success was defined as balloon inflation across the aortic annulus and a broader jet through the aortic valve as assessed by Doppler. Data collected included body mass index, demographic variables, ultrasound findings and postprocedure interventions.

Results

Technical success increased significantly if maternal laparotomy was an option (83.3% vs. 20.0%, P = 0.017). Laparotomy was performed in 66.6% (12/18) of cases. There was a learning curve that showed an increase in success rate and decrease in need for laparotomy over the 3‐year study period. Neither the need for laparotomy nor the chances of technical success were predictable by gestational age, body mass index or placental location. Tocolysis was limited to perioperative prophylaxis; one woman experienced wound infection and fluid overload. Postoperatively, three fetuses died and two delivered prematurely, 2 and 7 weeks after intervention.

Conclusion

Fetal aortic valvuloplasty can be performed with technical success, with low fetal loss rate and few maternal complications. While the need for laparotomy cannot be predicted, having it available as an option improves the technical success rate. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Changes in pulmonary venous Doppler parameters in fetal cardiac defects
Authors: Lenz F. , Chaoui R.
Published: June 2006

Objectives

Recent observations in pediatric cardiological studies have prompted discussion on the possible role of intrauterine pulmonary venous changes in neonatal and postoperative outcome of infants with congenital heart defects. This study analyzes changes of Doppler blood flow velocity waveforms in the pulmonary veins of fetuses with different cardiac defects.

Methods

Eighty fetuses (mean gestational age, 27 weeks) with prenatally diagnosed cardiac defects were classified into one of five groups: obstructed left atrium, other left ventricular outflow tract obstruction, right ventricular outflow tract obstruction, miscellaneous cardiac defects and total anomalous pulmonary venous drainage. Doppler examination of the pulmonary veins was performed and the time velocity integral (TVI), end‐diastolic (A) velocity, and pulsatility index for veins (PIV) were compared with reference ranges.

Results

Fetuses with infradiaphragmatic total anomalous pulmonary venous drainage showed a continuous Doppler flow pattern instead of the typical pulsatile waveform pattern. In fetuses with obstructed left atrium and restrictive foramen ovale, a reversed A‐velocity and increased PIV were found. In five of the eight fetuses with left outflow tract obstruction but patent mitral valve, PIV was increased. In the other groups there were no obvious changes in Doppler parameters.

Conclusions

We suggest routine examination of the pulmonary veins with pulsed Doppler ultrasound in every fetus with a prenatally diagnosed heart defect. Such Doppler parameters could be used in future as cut‐offs for the recently reported in‐utero atrial septostomy to decompress an obstructed left atrium. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Intracardiac Doppler assessment of left valve inflow in first‐trimester fetuses with increased nuchal translucency: preliminary observations in trisomy 21
Authors: Zoppi M. A. , Ibba R. M. , Floris M. , Manca F. , Axiana C. , Monni G.
Published: June 2006

Objectives

To perform a qualitative assessment of the pulsed Doppler waveform profile at the level of left atrioventricular valve inflow in first‐trimester fetuses with increased nuchal translucency thickness (NT), in order to compare those with trisomy 21 and those with normal karyotype.

Methods

This was a review of 285 consecutive fetuses with increased NT. Pulsed Doppler velocity waveforms of left atrioventricular valve inflow were recorded. The E‐wave, A‐wave and velocity profile in the aorta were displayed. Cases were classified into two patterns: Pattern A included those in which the E‐wave velocity crossed the A‐wave before the baseline in all waveforms; Pattern B included those in which the lowest E‐wave velocity crossed the baseline but not the A‐wave in at least one of the profiles. The karyotype was determined and the frequency of occurrence of Patterns A or B in fetuses with normal karyotype and those with trisomy 21 were compared.

Results

Of the 285 cases, 230 were assigned to Pattern A and 55 to Pattern B. There were 47 cases of trisomy 21, 22 had other chromosomal abnormalities, and 212 had a normal karyotype; in four cases the karyotype was unknown. Among the 212 karyotypically normal fetuses, five had heart defects, five had other structural defects, three suffered spontaneous intrauterine death and one was terminated. Pattern A was found in 200/212 (94.3%) cases with normal karyotype, in 12/47 (25.5%) cases with trisomy 21, and in 17/22 (77.3%) cases with other chromosomal abnormalities. Pattern B was found in 12/212 (5.7%) cases with normal karyotype, in 35/47 (74.5%) cases with trisomy 21 (chi‐square test, P < 0.001), and in 5/22 (22.7%) cases with other chromosomal abnormalities.

Conclusions

Intracardiac Doppler qualitative assessment of left valve inflow in first‐trimester fetuses with increased NT shows differences between normal and trisomy 21 fetuses, probably reflecting differences in myocardial function. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Computerized Navigation for Treatment of Slipped Femoral Capital Epiphysis
Authors: Weil Yoram , Pearle Andrew , Liebergall Meir , Simanovsky Naum , Porat Shlomo , Moshieff Rami
Published: June 2006

In situ pinning with a single screw is the treatment of choice for symptomatic slipped capital femoral epiphysis (SCFE). Some technical features are critical and include proper screw entry point, screw direction in relation to the epiphysis, and the length of screw. These are complicated by the deformity created as a result of the posterior slip of the epiphysis. Fluoroscopic based computerized navigation system can increase precision in screw placement while performing the surgical task, and markedly reduce radiation. By using real fluoroscopy-based navigation, the screw can be placed with only two fluoroscopic images. Entry point, length, and precise direction can all be easily determined through this technique.
Presenilin‐1 is an unprimed glycogen synthase kinase‐3β substrate
Authors: Twomey Ciara , McCarthy Justin V.
Published: June 2006

Previously we described presenilin‐1 (PS1) as a GSK‐3β substrate [Kirschenbaum, F., Hsu, S.C., Cordell, B. and McCarthy, J.V. (2001) Substitution of a glycogen synthase kinase‐3beta phosphorylation site in presenilin 1 separates presenilin function from beta‐catenin signalling. J. Biol. Chem. 276, 7366–7375; Kirschenbaum, F., Hsu, S.C., Cordell, B. and McCarthy, J.V. (2001) Glycogen synthase kinase‐3beta regulates presenilin 1 C‐terminal fragment levels. J. Biol. Chem. 276, 30701–30707], though it has not been determined whether PS1 is a primed or unprimed GSK‐3β substrate. A means of separating GSK‐3β activity toward primed and unprimed substrates was identified in the GSK‐3β‐R96A phosphate binding pocket mutant [Frame, S., Cohen, P. and Biondi, R.M. (2001) A common phosphate binding site explains the unique substrate specificity of GSK3 and its inactivation by phosphorylation. Mol. Cell 7, 1321–1327], which is unable to phosphorylate primed but retains the ability to phosphorylate unprimed GSK‐3β substrates. By using wild type GSK‐3β, GSK‐3β‐R96A, and a pharmacological modulator of GSK‐3β activity, we demonstrate that PS1 is an unprimed GSK‐3β substrate. These findings have important implications for regulation of PS1 function and the pathogenesis of Alzheimer's disease.
Appraising Democratic Consolidation in Thailand under Thaksin's Thai Rak Thai Government
Authors: GANESAN N.
Published: June 2006

This article identifies how democracy and transparency in Thailand have been subverted since 2001. Specifically, it appraises the sentiments and trends that have been in place since 1993 to prevent a return to authoritarian government. Additionally, it also examines structures and policies that have thwarted democratic consolidation since 2000. The central hypothesis of the article is that there has been a structural weakening of democracy in Thailand under the Thai Rak Thai government since 2001. In other words, Thailand's democratic consolidation has been held in abeyance since the electoral victory of the Thaksin government.

This study utilizes an admixture of the institutionalist and agency approaches to make its case. There is sufficient evidence to discern since 2001 the direction and nature of state–society relations in Thailand and Thaksin has also undertaken a number of policies by way of elite strategic choices. Consequently, bringing these two approaches into strategic convergence obtains better and more comprehensive results of the state of democratic consolidation in Thailand, both from an elite as well as societal perspective for a more balanced approach. The evidence culled thus far suggests that, whereas Thaksin came to power using democratic means and in fact consolidated his democratic credentials after his second victory in 2005, domestic political and social developments reflect a weaker commitment to democratic ideals and its structural and cultural consolidation.
EPspectra: a formal toolkit for developing DSP software applications
Authors: KIM HAHNSANG , TURLETTI THIERRY , BOUALI AMAR
Published: June 2006

The software approach to developing Digital Signal Processing (DSP) applications brings some great features such as flexibility, re-usability of resources and easy upgrading of applications. However, it requires long and tedious tests and verification phases because of the increasing complexity of the software applications. This implies the need of a software programming environment capable of putting together DSP modules and providing facilities to debug, verify and validate the code. The objective of the work is to provide such facilities as simulation and verification for developing DSP software applications. This led us to developing an extension toolkit, EPSPECTRA, built upon PSPECTRA, one of the first toolkits available to design basic software radio applications on standard PC workstations. In this paper, we first present EPSPECTRA, an ESTEREL-based extension of PSPECTRA that makes the design and implementation of portable DSP applications easier. It allows the drastic reduction of testing and verification time while requiring relatively little expertise in formal verification methods. Second, we demonstrate the use of EPSPECTRA, taking as an example the radio interface part of a GSM base station. We also present the verification procedures for the three safety properties of the implementation programs which have complex control-paths. These have to obey strict scheduling rules. In addition, EPSPECTRA achieves the verification of the targeted application since the same model is used for the executable code generation and for the formal verification.
Whistler‐mode auroral hiss emissions observed near Saturn's B ring
Authors: Xin L. , Gurnett D. A. , Santolík O. , Kurth W. S. , Hospodarsky G. B.
Published: June 2006

An unusual whistler‐mode emission, similar to terrestrial auroral hiss, was observed by the radio and plasma wave instrument on the Cassini spacecraft during the 1 July 2004 pass over the rings of Saturn. By using an electron density model that is consistent with measurements of the local electron plasma frequency, ray‐tracing calculations have been performed to determine the source of the emission. The calculations assume that the emission is propagating near the whistler‐mode resonance cone. It is found that the best fit to the V‐shaped lower cutoff of the emission is obtained if the source is located very close to the B ring at a distance of about 1.76 RS from the center of Saturn. On the basis of the close similarity to terrestrial auroral hiss we suggest that the emission is produced by a magnetic field‐aligned beam of electrons that is directed outward away from the ring. The electron beam is most likely accelerated by parallel electric fields that arise as part of a current system induced by the interaction of the ring with the corotating magnetosphere of Saturn.
Doppler frequency shift in ocean wave measurements: Frequency downshift of a fixed spectral wave number component by advection of wave orbital velocity
Authors: Hwang Paul A.
Published: June 2006

Because the Jacobian connecting wave number to frequency conversion is nonlinear, in the presence of background waves even without a mean current a wave number spectral component does not appear at the expected intrinsic frequency in the frequency spectrum measured by a stationary probe. The advection of the wave number component by the orbital current of background waves produces a net downshift in the encounter frequency. Comparison with laboratory measurements shows that the effect is important in low‐wind conditions. As wind speed increases, the frequency downshift due to orbital advection becomes less recognizable.
Modeling South China Sea circulation: Response to seasonal forcing regimes
Authors: Gan Jianping , Li H. , Curchitser E. N. , Haidvogel D. B.
Published: June 2006

A three‐dimensional ocean model has been utilized to study circulation and its seasonal variation in the South China Sea (SCS) in response to the forcing of the Asian monsoon and the Kuroshio intrusion. The SCS ocean model has a resolution of approximately 10 km horizontal spacing and 30 vertical levels with a realistic bottom topography. The model is forced with time‐dependent wind stress and heat flux from National Center for Environmental Prediction Reanalysis data as well as with lateral fluxes from a Pacific Ocean model of 40 km horizontal resolution. This study reports on the analysis of the mean seasonal circulation and dynamic processes in response to monsoonal wind stress, the Kuroshio intrusion, and other intrinsic forcing processes. It is found that the seasonal circulation in the SCS is mainly driven by the monsoonal wind stress and greatly influenced by the inflow from the Kuroshio intrusion. Strong currents along the continental margin of the SCS form mean basin‐wide cyclonic and anticyclonic circulations in the winter and summer, respectively. Multiscale eddies are embedded in the general circulation across the basin. While mainstream of the Kuroshio passes through the Luzon Strait without intruding into the SCS, partial intrusion occurs in the upper 200 m near the shelf margin southwest of Taiwan at times when winter dynamic conditions prevail in the north SCS. The intrusion of the Kuroshio into the SCS also occurs at depths in all seasons, mainly along the continental slope. The coastal current separation to the east off southern Vietnam and the associated eddy formations characterize the circulation in the south SCS. The simulated results compare well with the corresponding observed fields. Dynamical processes involved in the forced flow fields are investigated by examination of the momentum balances. The analyses reveal that the circulation in the SCS is generally dominated by the geostrophic currents. North of the Luzon Strait, positive nonlinearity in the zonal direction is locally intensified, which leads to the formation of centripetal acceleration for the mainstream of the Kuroshio to turn eastward. The Kuroshio intrusion at depths is governed by the ageostrophic flows and highly associated with the net westward pressure gradient force. Coastal jet separation to the east off Vietnam is mainly associated with the local wind stress field and with the shelf topography in the summer and winter, respectively. Sensitivity study reveals that the weakening of the Kuroshio markedly enhances Kuroshio's intrusion and forms an anticyclonic eddy west of the Luzon Strait.
A Kalman filter reconstruction of the vertical ozone distribution in an equivalent latitude–potential temperature framework from TOMS/GOME/SBUV total ozone observations
Authors: Brunner D. , Staehelin J. , Künsch H.‐R. , Bodeker G. E.
Published: June 2006

We present a quasi three‐dimensional ozone data set (Candidoz Assimilated Three‐dimensional Ozone, CATO) with daily resolution and covering the period 1979–2004. It was reconstructed from two‐dimensional total ozone observations of the Total Ozone Mapping Spectrometer (TOMS), Global Ozone Monitoring Experiment (GOME), and Solar Backscatter UV (SBUV) satellite instruments by assimilating the measurements into an equivalent latitude (ϕE)–potential temperature (θ) framework. The statistical reconstruction method uses the fact that total ozone columns are influenced by transient north‐south excursions of air parcels associated, for instance, with Rossby waves. These adiabatic motions change the thickness of individual isentropic layers and transport high or low ozone into the column depending on meridional concentration gradients. A Kalman filter was employed to calculate sequentially the ozone distributions on a (ϕE, θ) grid that best match the total ozone observations given the errors in both the measurements and the ozone field predicted by the filter. CATO is shown to agree in midlatitudes within 20% with ozonesondes and the Halogen Occultation Experiment (HALOE) capturing both seasonal and interannual variations. Significantly larger differences of about 30% are found at the high‐latitude sonde station Sodankylä (67°N), while differences from HALOE are mostly within 20% at these latitudes. Differences of about 30% from both the sondes and HALOE are found in the tropical lower stratosphere. This new data set is unique in its temporal and spatial coverage and will be particularly useful for studies of the factors influencing the long‐term evolution of ozone in the lower stratosphere.
Uncertainty estimates in regional and global observed temperature changes: A new data set from 1850
Authors: Brohan P. , Kennedy J. J. , Harris I. , Tett S. F. B. , Jones P. D.
Published: June 2006

The historical surface temperature data set HadCRUT provides a record of surface temperature trends and variability since 1850. A new version of this data set, HadCRUT3, has been produced, benefiting from recent improvements to the sea surface temperature data set which forms its marine component, and from improvements to the station records which provide the land data. A comprehensive set of uncertainty estimates has been derived to accompany the data: Estimates of measurement and sampling error, temperature bias effects, and the effect of limited observational coverage on large‐scale averages have all been made. Since the mid twentieth century the uncertainties in global and hemispheric mean temperatures are small, and the temperature increase greatly exceeds its uncertainty. In earlier periods the uncertainties are larger, but the temperature increase over the twentieth century is still significantly larger than its uncertainty.
Erosion rates during rapid deglaciation in Icy Bay, Alaska
Authors: Koppes Michèle , Hallet Bernard
Published: June 2006

Contemporary glacial erosion rates based on sediment yields in southeast Alaska merit considerable attention because they are unsurpassed worldwide, and they significantly exceed long‐term exhumation rates in the region. Two issues are likely to contribute to these high rates: contemporary sediment yields in fjords (1) have generally been overestimated by failing to account for the considerable input of subaerially derived material and (2) are exceptionally high because tidewater glaciers in southeast Alaska have been anomalously dynamic and erosive during the past century of rapid retreat. To investigate these influences and to quantify the rate at which Tyndall Glacier erodes its basin we present seismic data defining the volume of sediments in Taan Fjord, Icy Bay. We subtract the contribution of subaerially derived sediments from the fjord sediment package to determine the sediment yield directly from Tyndall Glacier during the most recent period of retreat: 1962–1999. Using a numerical model of proglacial glacimarine sedimentation, we then calculate the annual sediment yield from, and the corresponding erosion rate of, Tyndall Glacier during this period, which averages 28 ± 5 mma−1. A strong correlation emerges between glacial retreat rates and glacial sediment yields, implying that most contemporary sediment yield data from retreating tidewater glaciers may correspond to contemporary erosion rates that are a factor of 3.5 ± 1.5 higher than in the long term. Hence we estimate the long‐term erosion rate for Tyndall Glacier to be 9 ± 2 mma−1.
Evaluating the seasonal and interannual variations in water balance in northern Wisconsin using a land surface model
Authors: Vano Julie A. , Foley Jonathan A. , Kucharik Christopher J. , Coe Michael T.
Published: June 2006

We evaluated the performance of the Integrated BIosphere Simulator (IBIS) land surface model in the temperate forests of northern Wisconsin (46°N, 89°W) to determine whether model formulations, driven with daily historical precipitation, temperature, relative humidity, solar radiation, and wind speed data, were capable of simulating water flow and storage within a seasonally cold climate regime. We focused concurrently on understanding seasonal and interannual variations of both the water fluxes to the atmosphere and water partitioned into surface runoff and groundwater infiltration, with special attention to the transitions from cold‐dominated (snow, ice) to warm‐dominated (rain, liquid soil moisture) hydrology. Results showed when compared with a suite of field observations IBIS simulated water and energy cycling at daily to interannual timescales with reasonable accuracy. Because of errors associated with field observations, the accuracy with which we simulated each component of the water balance is not easily quantified. By investigating the complete land surface water balance, however, we increased the likelihood that all components were being captured. The modeled monthly energy balance, annual water balance, and drainage rates were generally within 5–15% of the observed values. Modeled and observed soil temperatures generally differed by less than 3°C and had r2values that were greater than 0.9. Soil moisture values were within 5–20%, and freeze and thaw timing was within a few days of observations. Modeled snow dynamics captured the observed snow arrival and departure (accumulation on the surface) within a few days of observations, but overestimated the average maximum depth by 86%. Because model formulations were subjected to varying soil conditions and water phases, this evaluation exercise enhanced our understanding of northern Wisconsin's water balance and increased model credibility for applications in seasonally cold climates.
Numerical simulation of internal tides and the resulting energetics within Monterey Bay and the surrounding area
Authors: Jachec S. M. , Fringer O. B. , Gerritsen M. G. , Street R. L.
Published: June 2006

We use a three‐dimensional nonhydrostatic unstructured‐grid code to simulate internal tides within Monterey Bay. The predicted water surface, barotropic and baroclinic velocities, and internal tides in the greater coastal region agree with observations. The agreement is due to the use of a high‐resolution mesh, alongshore prescription of the barotropic M2 tidal velocities, and specification of initial conditions consistent with field data. Results of depth‐integrated, M2‐period‐averaged energy flux and energy flux divergence are presented in order to identify locations of significant internal wave generation and dissipation. Based on the results, there is a domain‐wide power surplus of +52 MW due to internal tides that is available for pelagic mixing, yet isolated bathymetric features, such as Monterey Submarine Canyon and Smooth Ridge, are net dissipative, with dissipation rates of −8.3 and −1.5 MW, respectively.
Internal ribosome entry sequence‐mediated translation initiation triggers nonsense‐mediated decay
Authors: Holbrook Jill A , Neu‐Yilik Gabriele , Gehring Niels H , Kulozik Andreas E , Hentze Matthias W
Published: June 2006

In eukaryotes, a surveillance pathway known as nonsense‐mediated decay (NMD) regulates the abundance of messenger RNAs containing premature termination codons (PTCs). In mammalian cells, it has been asserted that the NMD‐relevant first round of translation is special and involves initiation by a specific protein heterodimer, the nuclear cap‐binding complex (CBC). Arguing against a requirement for CBC‐mediated translation initiation, we show that ribosomal recruitment by the internal ribosomal entry sequence of the encephalomyocarditis virus triggers NMD of a PTC‐containing transcript under conditions in which ribosome entry from the cap is prohibited. These data generalize the previous model and suggest that translation per se, irrespective of how it is initiated, can mediate NMD.
ORC binding to TRF2 stimulates OriP replication
Authors: Atanasiu Constandache , Deng Zhong , Wiedmer Andreas , Norseen Julie , Lieberman Paul M
Published: June 2006

In higher eukaryotes, the origin recognition complex (ORC) lacks sequence‐specific DNA binding, and it remains unclear what other factors specify an origin of DNA replication. The Epstein–Barr virus origin of plasmid replication (OriP) recruits ORC, but the precise mechanism of ORC recruitment and origin activation is not clear. We now show that ORC is recruited selectively to the dyad symmetry (DS) region of OriP as a consequence of direct interactions with telomere repeat factor 2 (TRF2) and ORC1. TRF‐binding sites within DS stimulate replication initiation and facilitate ORC recruitment in vitro and in vivo. TRF2, but not TRF1 or hRap1, recruits ORC from nuclear extracts. The amino‐terminal domain of TRF2 associated with a specific region of ORC1 and was necessary for stimulation of DNA replication. These results support a model in which TRF2 stimulates OriP replication activity by direct binding with ORC subunits.
Rapid peptide bond formation on isolated 50S ribosomal subunits
Authors: Wohlgemuth Ingo , Beringer Malte , Rodnina Marina V
Published: June 2006

The catalytic site of the ribosome, the peptidyl transferase centre, is located on the large (50S in bacteria) ribosomal subunit. On the basis of results obtained with small substrate analogues, isolated 50S subunits seem to be less active in peptide bond formation than 70S ribosomes by several orders of magnitude, suggesting that the reaction mechanisms on 50S subunits and 70S ribosomes may be different. Here we show that with full‐size fMet‐tRNAfMet and puromycin or C‐puromycin as peptide donor and acceptor substrates, respectively, the reaction proceeds as rapidly on 50S subunits as on 70S ribosomes, indicating that the intrinsic activity of 50S subunits is not different from that of 70S ribosomes. The faster reaction on 50S subunits with fMet‐tRNAfMet, compared with oligonucleotide substrate analogues, suggests that full‐size transfer RNA in the P site is important for maintaining the active conformation of the peptidyl transferase centre.
Broadening of DNA replication origin usage during metazoan cell differentiation
Authors: Dazy Sébastien , Gandrillon Olivier , Hyrien Olivier , Prioleau Marie‐Noëlle
Published: June 2006

We have examined whether replication of the chicken β‐globin locus changes during differentiation of primary erythroid progenitors into erythrocytes. In undifferentiated progenitors, four principal initiation sites and a replication fork pausing region (RFP) were observed. Forty‐eight hours after induction of differentiation, the principal sites were maintained, even in the activated βA‐globin gene, some minor sites were enhanced, three new sites appeared and the RFP disappeared. One of the activated origins showed increased histone H3 K9K14 diacetylation, but the others did not. These results demonstrate a broadening of DNA replication origin usage during differentiation of untransformed metazoan cells and indicate that histone H3 diacetylation, other histone modifications so far reported and transcription are not crucial determinants of origin selection in this system.