bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimating return periods of extreme events from ECMWF seasonal forecast ensembles
Authors: van den Brink H. W. , Können G. P. , Opsteegh J. D. , van Oldenborgh G. J. , Burgers G.
Published: August 2005

Meteorological extremes have large impacts on society. The fact that approximately 40% of the Netherlands is below sea level makes this country especially vulnerable to flooding, both from the sea and from rivers. This has resulted in extensive research on the statistics of extremes. However, applications to meteorological and hydrological situations are always hampered by the brevity of the available datasets, as the required return levels exceed the record lengths by a factor of 10 to 100. In order to overcome this problem, we use archived data from all past seasonal forecast ensemble runs of the European Centre for Medium‐Range Weather Forecasts (ECMWF) since 1987 as input for extreme‐value statistics analysis. We make use of the fact that the seasonal forecast has little seasonal skill for the Netherlands, which implies that the ensembles can be regarded as independent sets that cumulate to over 1500 years.

We investigate the hydraulic response in the Netherlands to extreme synoptic‐scale weather systems by studying the extreme‐value distributions of sea storm surge levels, waves and river discharges. The application is detailed in four practical examples originating from coastal protection, river flooding protection, and water management problems. The long record length of the ECMWF data reduces the uncertainty in the 103‐year and the 104‐year return values considerably with respect to the results based on observational time series. The ECMWF dataset gives the opportunity to explore the distribution of events that depend on several kinds of extreme. Copyright © 2005 Royal Meteorological Society.
Change in mean temperature as a predictor of extreme temperature change in the Asia–Pacific region
Authors: Griffiths G. M. , Chambers L. E. , Haylock M. R. , Manton M. J. , Nicholls N. , Baek H.‐J. , Choi Y. , Della‐Marta P. M. , Gosai A. , Iga N. , Lata R. , Laurent V. , Maitrepierre L. , Nakamigawa H. , Ouprasitwong N. , Solofa D. , Tahani L. , Thuy D. T. , Tibig L. , Trewin B. , Vediapan K. , Zhai P.
Published: August 2005

Trends (1961–2003) in daily maximum and minimum temperatures, extremes and variance were found to be spatially coherent across the Asia–Pacific region. The majority of stations exhibited significant trends: increases in mean maximum and mean minimum temperature, decreases in cold nights and cool days, and increases in warm nights. No station showed a significant increase in cold days or cold nights, but a few sites showed significant decreases in hot days and warm nights. Significant decreases were observed in both maximum and minimum temperature standard deviation in China, Korea and some stations in Japan (probably reflecting urbanization effects), but also for some Thailand and coastal Australian sites. The South Pacific convergence zone (SPCZ) region between Fiji and the Solomon Islands showed a significant increase in maximum temperature variability.

Correlations between mean temperature and the frequency of extreme temperatures were strongest in the tropical Pacific Ocean from French Polynesia to Papua New Guinea, Malaysia, the Philippines, Thailand and southern Japan. Correlations were weaker at continental or higher latitude locations, which may partly reflect urbanization.

For non‐urban stations, the dominant distribution change for both maximum and minimum temperature involved a change in the mean, impacting on one or both extremes, with no change in standard deviation. This occurred from French Polynesia to Papua New Guinea (except for maximum temperature changes near the SPCZ), in Malaysia, the Philippines, and several outlying Japanese islands. For urbanized stations the dominant change was a change in the mean and variance, impacting on one or both extremes. This result was particularly evident for minimum temperature.

The results presented here, for non‐urban tropical and maritime locations in the Asia–Pacific region, support the hypothesis that changes in mean temperature may be used to predict changes in extreme temperatures. At urbanized or higher latitude locations, changes in variance should be incorporated. Copyright © 2005 Royal Meteorological Society.
Deconvolution of laser based images for monitoring rheumatoid
arthritis
Authors: Minet O , Zabarylo U , Beuthan J
Published: August 2005

Optical imaging in biomedicine is governed by the light
absorption and scattering interaction on microscopic and
macroscopic constituents in the medium. Therefore, light
scattering characteristics of human tissue correlate with the
stage of some diseases. In the near infrared range the scattering
event with the coefficient approximately two orders of magnitude
greater than absorption plays a dominant role. When measuring the
optical parameters variations were discovered that correlate with
the rheumatoid arthritis of a small joint. The potential of an
experimental setup for transillumination of the finger joint with
a laser diode and the pattern of the stray light detection are
demonstrated. The scattering caused by skin contains no useful
information and it can be removed by a deconvolution technique to
enhance the diagnostic value of this non-invasive optical method.
Monte Carlo simulations ensure both the construction of the
corresponding point spread function and the theoretical
verification of the stray light picture in rather complex
geometry.
Effect of β‐Sheet Crystals on the Thermal and Rheological Behavior of Protein‐Based Hydrogels Derived from Gelatin and Silk Fibroin
Authors: Gil Eun S. , Spontak Richard J. , Hudson Samuel M.
Published: August 2005

Summary: Novel protein‐based hydrogels have been prepared by blending gelatin (G) with amorphous Bombyx mori silk fibroin (SF) and subsequently promoting the formation of β‐sheet crystals in SF upon exposure to methanol or methanol/water solutions. Differential scanning calorimetry of the resultant hydrogels confirms the presence and thermoreversibility of the G helix‐coil transition between ambient and body temperature at high G concentrations. At low G concentrations, this transition is shifted to higher temperatures and becomes progressively less pronounced. Complementary dynamic rheological measurements reveal solid‐liquid cross‐over at the G helix‐coil transition temperature typically between 30 and 36 °C in blends prior to the formation of β‐sheet crystals. Introducing the β‐sheet conformation in SF stabilizes the hydrogel network and extends the solid‐like behavior of the hydrogels to elevated temperatures beyond body temperature with as little as 10 wt.‐% SF. The temperature‐dependent elastic modulus across the G helix‐coil transition is reversible, indicating that the conformational change in G can be used in stabilized G/SF hydrogels to induce thermally triggered encapsulant release.

Thermally reversible helix‐coil conformational transition of gelatin in mixed gelatin/silk fibroin hydrogels.

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Thermally reversible helix‐coil conformational transition of gelatin in mixed gelatin/silk fibroin hydrogels.
Novel Polymers to Study the Influence of the Azobenzene Content on the Photo‐Induced Surface Relief Grating Formation
Authors: Börger Volker , Kuliskovska Olga , G.‐Hubmann Kati , Stumpe Joachim , Huber Marco , Menzel Henning
Published: August 2005

Summary: The influence of the azobenzene concentration on the photo‐induced surface relief grating (SRG) formation in polymer films was investigated. Two series of polymers with 4‐alkoxy‐4′‐cyanoazobenzene side groups were synthesized. In series A, the degree of substitution was varied, while in series B, azobenzene and biphenyl groups were introduced in varying composition, but the concentration of non‐reacted HEMA‐groups was kept constant. Photo‐induction of the dichroism and the SRG was studied as function of the azobenzene concentration. An optimum was found for the SRG formation (76%), while the highest dichroism was induced at the lowest azobenzene concentration of 20%. The restriction of rotational and translational molecular motions observed at higher azobenzene concentration was explained by π‐π stacking of the azobenzene moieties and interaction of unreacted HEMA groups.

AFM topography image of surface relief grating in polymer B‐76.

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AFM topography image of surface relief grating in polymer B‐76.
Definability degrees
Authors: Friedman Sy D.
Published: August 2005

We establish the equiconsistency of a simple statement in definability theory with the failure of the GCH at all infinite cardinals. The latter was shown by Foreman and Woodin ([2]) to be consistent, relative to the existence of large cardinals. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of Polyelectrolyte Structural Features on Flocculation Behavior: Cationic Polysaccharides vs. Synthetic Polycations
Authors: Bratskaya Svetlana , Schwarz Simona , Laube Johannes , Liebert Tim , Heinze Thomas , Krentz Oliver , Lohmann Claudia , Kulicke Werner‐Michael
Published: August 2005

Summary: Growing demand for environmentally friendly technologies promotes the interest in investigation of natural flocculants and development of new ways of their derivatization aimed to find a compromise between cost, efficiency, and safety in polyelectrolyte applications. Recent progress in cationization of natural starch [T. Heinze et al., Macromol. Mater. Eng. 2002, 287, 495] allowed obtaining cationic starch derivatives (2‐hydroxy‐3‐trimethylammoniumpropyl starch chloride) with very high substitution degrees (up to 1.54) that made them together with aminopolysaccharide chitosan the most promising candidates to replace synthetic flocculants in various industrial sectors. In this paper the flocculation efficiency of chitosan, cationic polyacrylamide copolymers (Praestols), and two series of cationic starch derivatives varying in substitution degree and amylose/amylopectin ratio is investigated to answer the following questions: do cationic polysaccharides and synthetic polymers show comparable efficiency; does high degree of starch functionalization significantly improve its flocculation behavior in comparison with commercially available starch products; and whether the amylose/amylopectin ratio (i.e. ratio of linear/branched polymers) plays a role in flocculation behavior of highly substituted cationic starch derivatives.

Chemical structures of chitosan and cationic starch derivatives.

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Chemical structures of chitosan and cationic starch derivatives.
Poly(N‐isopropylacrylamide) Nanoparticle‐Incorporated PNIPAAm Hydrogels with Fast Shrinking Kinetics
Authors: Zhang Jian‐Tao , Huang Shi‐Wen , Xue Ya‐Nan , Zhuo Ren‐Xi
Published: August 2005

Summary: Novel temperature‐responsive poly(N‐isopropylacrylamide) (PNIPAAm) nanoparticle‐containing PNIPAAm hydrogels were prepared by radical polymerization. In comparison with conventional PNIPAAm hydrogels, the PNIPAAm gels thus prepared exhibit much faster response rates as the temperature is raised above the lower critical solution temperature. The improved properties are a result of the incorporation of PNIPAAm particles, which first shrink and then generate pores for water molecules to be quickly squeezed out of the bulky PNIPAAm gels.

Schematic illustration of the shrinking process: (I) First PNIPAAm particles shrink and generate pores; (II) the bulky gels then shrink further at a rapid rate.

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Schematic illustration of the shrinking process: (I) First PNIPAAm particles shrink and generate pores; (II) the bulky gels then shrink further at a rapid rate.
Fluctuation‐Assisted Crystallization: In a Simultaneous Phase Separation and Crystallization Polyolefin Blend System
Authors: Zhang Xiaohua , Wang Zhigang , Muthukumar Murugappan , Han Charles C.
Published: August 2005

Summary: The liquid‐liquid phase separation (LLPS) is often coupled with other ordering processes such as crystallization. In a polyolefin blend system, overwhelming changes in crystallization kinetics due to concentration fluctuation caused by spontaneous spinodal LLPS have been observed. Consequently, we are proposing a new mechanism of “fluctuation‐assisted crystallization”. In this process, the usual nucleation barrier could be overcome (or at least partially) by the spontaneous fluctuation growth of LLPS in the spinodal region.

Time‐resolved polarized optical micrographs for poly(ethylene‐co‐hexene) (PEH)/poly(ethylene‐co‐butene) (PEB) = 40:60 isothermally crystallized at 117 °C for 2 min after LLPS at 135 °C for the times shown and the nucleation rates at 117 °C as a function of LLPS time at 135 °C.

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Time‐resolved polarized optical micrographs for poly(ethylene‐co‐hexene) (PEH)/poly(ethylene‐co‐butene) (PEB) = 40:60 isothermally crystallized at 117 °C for 2 min after LLPS at 135 °C for the times shown and the nucleation rates at 117 °C as a function of LLPS time at 135 °C.
Biodegradable Poly(ester hydrazide)s via Enzymatic Polymerization
Authors: Métral Guillaume , Wentland Jewgenia , Thomann Yi , Tiller Joerg C.
Published: August 2005

Summary: The reaction of hydrazine with ethyl glycolate results in 1,2‐bisglycoylhydrazine, a monomer that was used for the lipase‐catalyzed synthesis of biodegradable poly(ester hydrazide)s. The polymers derived from the hydrazide‐containing monomer and vinyl‐activated adipic, suberic, and sebacic acid, respectively, showed low melting temperatures of 136 to 141 °C and are thermally stable up to 300 °C. The aliphatic poly(ester hydrazide)s (PEHs) are highly crystalline, as proven by polarization microscopy and atomic force microscopy. Further, the PEHs represent the first described biodegradable poly(hydrazide)s. They degrade in the presence of lipase at 37 °C within a few weeks.

Synthetic route to poly(ester hydrazide)s.

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Synthetic route to poly(ester hydrazide)s.
Heat Stabilizers as Activators in Coordination Polymerization
Authors: Schellenberg Jürgen
Published: August 2005

Summary: The solvent‐free syndiospecific styrene polymerization as an example of a coordination polymerization has been investigated with a catalyst system consisting of η5‐octahydrofluorenyl titanium trimethoxide as a transition metal catalyst, MAO as a cocatalyst, and TIBA, in the presence of reaction products of sterically hindered phenolic compounds, usually applied as heat stabilizers of polymers. Unexpectedly, such reaction products led to a significant increase in polymerization activity of the catalyst system. Second, after deactivation of the catalyst system, such activators result in a significantly enhanced thermal stability of the syndiotactic polymers received.

Effect of the P8‐activator on polymerization activity in dependence on polymerization time (molar ratio–styrene:MAO:TIBA:P:Ti = 700 000:50:25:25:1; molar ratio–phenolic compound:TIBA = 1:3.2; polymerization temperature: 50 °C).

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Effect of the P8‐activator on polymerization activity in dependence on polymerization time (molar ratio–styrene:MAO:TIBA:P:Ti = 700 000:50:25:25:1; molar ratio–phenolic compound:TIBA = 1:3.2; polymerization temperature: 50 °C).
Mouse diaphragm assay for detection of antibodies against botulinum toxin type B
Authors: Dressler Dirk , Lange M. , Bigalke Hans
Published: August 2005

With the advent of a commercial preparation of botulinum toxin type B (BT‐B) for treatment of cervical dystonia detection of antibodies against BT‐B (BT‐B‐AB) becomes necessary. For this purpose, we carried out a mouse diaphragm assay (MDA) by continuous measurement of the twitch force of a mouse hemidiaphragm preparation elicited by electric stimulation of its phrenic nerve. After exposing the preparation to BT‐B 3 ng/ml the time to half‐maximal twitch force reduction (paralysis time [PT]) was 69 ± 4 min (n = 25). Addition of sera from patients with antibodies against BT‐A produced a PT of 68 ± 5 min (n = 24), whereas addition of sera from controls with antibodies against tetanus toxoid produced a PT of 67 ± 6 min (n = 30). When defined amounts of BT‐B‐AB were added to the MDA, PT was prolonged. This prolongation was correlated closely to the amount of BT‐B‐AB added, thus producing a calibration curve. The threshold for BT‐B‐AB detection was 0.4 mU/ml. When sera from 7 patients (4 women, 3 men; age 50.6 ± 14.2 years) with cervical dystonia (Toronto Western Spasmodic Torticollis Rating Scale score, 18.9 ± 2.9) and complete secondary failure of BT‐B therapy (NeuroBloc; Elan Pharmaceuticals, Shannon, Ireland; 12,229 ± 2,601 MU/injection series, 1.86 ± 0.69 injection series before complete secondary therapy failure; 100.4 ± 15.8 days between injection series with normal therapeutic effect) were tested, BT‐B‐AB titers of more than 10 mU/ml were found in all of them. The MDA can be used to measure neutralizing BT‐B‐AB titers quantitatively and with adequate sensitivity and specificity. Further studies are necessary to understand the role of intermediate BT‐B‐AB titers in partial BT‐B therapy failure. © 2005 Movement Disorder Society
Daytime sleep latency in medication‐matched parkinsonian patients with and without sudden onset of sleep
Authors: Möller J. Carsten , Rethfeldt Mira , Körner Yvonne , Stiasny‐Kolster Karin , Cassel Werner , Meindorfner Charlotte , Rissling Ida , Krüger Hans‐Peter , Oertel Wolfgang H.
Published: August 2005

Currently, it is unclear whether sleep attacks in Parkinson's disease (PD) represent a novel entity or just a phenomenon of daytime sleepiness. We investigated 10 PD patients with sleep attacks and compared them with 10 PD patients without any daytime sleepiness. The patients were matched according to their dopaminergic medication and subjected to a sleep medical investigation. The mean sleep latency on the multiple sleep latency test was in the normal range and not significantly different between the groups. These data suggest that sleep attacks can occur against a background of normal alertness. © 2005 Movement Disorder Society
Sperm dysfunction in the Rb(6.16)‐ and Rb(6.15)‐bearing mice revisited: Involvement of Hyalp1 and Hyal5
Authors: Zhang Hong , Shertok Stacy , Miller Kimberly , Taylor Leslie , Martin‐DeLeon Patricia A.
Published: August 2005

Earlier we showed that Sperm adhesion molecule1 (Spam1), the best studied sperm hyaluronidase, is involved in the sperm dysfunction associated with Robertsonian translocations (Rb). The dysfunction results in reduced fertility in mice homozygous for the Rb(6.16) or the Rb(6.15) translocation and transmission ratio distortion (TRD) in heterozygous males. This conclusion was based on the finding that Spam1 in the Rbs harbors multiple point mutations and a genomic alteration at the locus [in the case of Rb(6.16)]; and is accompanied by reduced steady‐state levels of the RNA and protein. Here we show that closely linked family members in the hyaluronidase gene cluster on mouse chromosome 6, Hyalp1 and Hyal5, also harbor point mutations in these Rbs, leading to nonconservative substitutions in both the encoded proteins. To test if Spam1 by itself is capable of producing TRD we analyzed the transmission of wild‐type and null alleles of the gene in the progeny of carriers and show that there is no significant TRD. This lack of TRD in null carriers argues for only a contributory role of Spam1 in the TRD seen in the Rb‐bearing mice, and supports the involvement of Hyalp1 and/or Hyal5 in the sperm dysfunction and the resulting TRD. It is proposed that the clustering of point mutations in all three genes results from the cumulative effect of spontaneous mutations that do not disperse in the population due to suppression of recombination that occurs at Rb junctions. Mol. Reprod. Dev. © 2005 Wiley‐Liss, Inc.
Differential development of rabbit embryos following microinsemination with sperm and spermatids
Authors: Ogonuki Narumi , Inoue Kimiko , Miki Hiromi , Mochida Keiji , Hatori Masanori , Okada Hironori , Takeiri Shuji , Shimozawa Nobuhiro , Nagashima Hiroshi , Sankai Tadashi , Ogura Atsuo
Published: August 2005

Microinsemination is the technique of delivering male germ cells directly into oocytes. The efficiency of fertilization after microinsemination and subsequent embryo development may vary with the animal species and male germ cells used. The present study was undertaken to observe the in vitro and in vivo developmental ability of rabbit embryos following microinsemination with male germ cells at different stages. First, we assessed their oocyte‐activating capacity by injecting them into mouse and rabbit oocytes. The majority of mouse oocytes were activated irrespective of the type of rabbit male germ cell injected (61–77%), whereas rabbit oocytes were activated differently according to the type of male germ cells (89%, 75%, and 29% were activated by spermatozoa, elongated spermatids, and round spermatids, respectively; P < 0.05). After 120 hr in culture, 66%, 45%, and 13%, respectively, of these activated rabbit oocytes (pronuclear eggs) developed into blastocysts (P < 0.05). Additional electric pulse stimulation of round spermatid‐injected oocytes increased the blastocyst rate to 43%. After 24 hr in culture, some four to eight cell embryos were transferred into the oviducts of pseudopregnant females. Normal pups were born from spermatozoa and elongated spermatids, but not from round spermatids. Karyotypic analysis at the morula/blastocyst stage revealed that the majority of round spermatid‐derived embryos had abnormal ploidy (8 out of 12 embryos). Our study indicates that rabbit male germ cells acquire the ability to activate oocytes and to support subsequent embryo development as they undergo spermiogenesis. As these differential developmental patterns are similar to those reported for humans in vitro and in vivo, rabbits may provide an alternative small animal model for studying the biological nature and molecular basis of human microinsemination techniques, especially those using immature male germ cells. Mol. Reprod. Dev. © 2005 Wiley‐Liss, Inc.
FDG PET for the study of primary hepatic malignancies in children
Authors: Mody Rajen J. , Pohlen Judith A. , Malde Sachit , Strouse Peter J. , Shulkin Barry L.
Published: August 2005

Purpose

This manuscript describes the use of FDG PET in a series of 7 children (11 scans) with primary hepatic malignancies (5 patients with hepatoblastoma, 2 patients with hepatic embryonal rhabdomyosarcoma), together with other imaging (CT and MRI), serum tumor markers, and tumor pathology.

Materials and Methods

Seven children with pathologically proven hepatic malignancies underwent 11 FDG PET scans for staging (1 patient) or restaging (6 patients). Tumor uptake of FDG was assessed qualitatively and compared with biochemical and radiological findings.

Results

Abnormal uptake was demonstrated in 6 of 7 patients (10 of 11 scans). Three patients subsequently underwent partial hepatic resection, and one underwent brain biopsy, confirming in each that the abnormal uptake of FDG indicated viable tumor. In one patient, intense uptake was due to necrotizing granulomas. In one patient, images were suboptimal due to noncompliance with fasting.

Conclusion

Primary hepatic tumors of childhood usually demonstrate increased glycolytic activity, which allows them to be imaged using PET and the tracer 18F‐FDG. The technique is probably most useful for assessing response to therapy, in following AFP (alfa fetoprotein) negative cases and for detecting metastatic disease although a large series of patients will need to be studied to confirm our initial findings. Non neoplastic inflammation may also accumulate FDG and could be confused with malignancy. As these tumors are rare, prospective multicenter studies are necessary to determine the true clinical utility of FDG PET imaging in the management of children with primary hepatic malignancies. © 2005 Wiley‐Liss, Inc.
Therapy‐related acute myeloid leukemia in a child with Noonan syndrome and clonal duplication of the germline PTPN11 mutation
Authors: Chantrain Christophe F. , Jijon Priscilla , De Raedt Thomas , Vermylen Christiane , Poirel Hélène A. , Legius Eric , Brichard Bénédicte
Published: August 2005

A 4‐year‐old girl with Noonan syndrome (NS) and constitutive PTPN11 mutation presented with stage 4 neuroblastoma and was treated by intensive chemotherapy. During the treatment, cytogenetic analysis revealed the development of a hyperdiploid clone with duplication of the germline PTPN11 mutation in a morphologically normal bone marrow. A few months later, the patient developed acute myelomonoblastic leukemia with an additional clonal deletion of 7q. Although, we cannot conclude whether there is an association between NS and neuroblastoma, this case suggests that duplication of germline PTPN11 mutations, potentially induced by chemotherapy, contributes to leukemogenesis in patients with NS. Pediatr Blood Cancer 2007;48:101–104. © 2005 Wiley‐Liss, Inc.
Studies of the properties of a thermosetting epoxy modified with block copolymers
Authors: He Shangjin , Wang Xiaobing , Guo Xianzhi , Shi Keyu , Du Zongjie , Zhang Baolong
Published: August 2005

Poly[(n‐butyl acrylate)‐block‐poly(methyl methacrylate)‐co‐(glycidyl methacrylate)] (BMG) diblock copolymers incorporating an epoxy‐reactive functionality in one block have been synthesized and used as modifiers for the model epoxy resin E‐51 cured with 4,4′‐diaminodiphenyl methane (DDM). The properties and morphologies of the modified epoxy thermosets were investigated by dynamic mechanical analysis (DMA), impact testing and scanning electron microscopy (SEM). The results reveal that addition of the block copolymers leaves the glass transition temperatures of the blends relatively unchanged, with small decreases in the storage moduli at room temperature. The toughening effect is dependent on the chemical structures of the block copolymers and an increase in the impact strength by a factor of two was obtained by the addition of ‘relatively symmetrical’ block copolymers. Moreover, the impact test results are consistent with the morphologies of the fracture surfaces as evidenced by SEM. Copyright © 2005 Society of Chemical Industry
Melt amination of polypropylenes
Authors: Lu Q.‐W. , Macosko C. W. , Horrion J.
Published: August 2005

Amine (primary and secondary) functional polypropylenes were prepared by the melt blending of maleated polypropylenes with small diamines, including hexamethylenediamine (primary–primary diamine), p‐xylylenediamine (primary–primary diamine), and N‐hexylethylenediamine (primary–secondary diamine), at various diamine/anhydride molar ratios in a batch mixer and a twin‐screw extruder. The experimental conversion data by Fourier transform infrared nearly agreed with the assumption of a complete reaction between the primary amine and anhydride. Chain extensions of the maleated polypropylenes by the diamines were monitored by the torques during mixing and further evaluated by rheological (dynamic shear rheometry) and mechanical measurements. We show that these amino polypropylenes are very effective adhesion promoters and compatibilizers of thermoplastic polyurethanes with polypropylene. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4217–4232, 2005
Study of the insulin dimerization: Binding free energy calculations and per‐residue free energy decomposition
Authors: Zoete Vincent , Meuwly Markus , Karplus Martin
Published: August 2005

A calculation of the binding free energy for the dimerization of insulin has been performed using the molecular mechanics–generalized Born surface area approach. The calculated absolute binding free energy is −11.9 kcal/mol, in approximate agreement with the experimental value of −7.2 kcal/mol. The results show that the dimerization is mainly due to nonpolar interactions. The role of the hydrogen bonds between the 2 monomers appears to give the direction of the interactions. A per‐atom decomposition of the binding free energy has been performed to identify the residues contributing most to the self association free energy. Residues B24–B26 are found to make the largest favorable contributions to the dimerization. Other residues situated at the interface between the 2 monomers were found to make favorable but smaller contributions to the dimerization: Tyr B16, Val B12, and Pro B28, and to an even lesser extent, Gly B23. The energy decomposition on a per‐residue basis is in agreement with experimental alanine scanning data. The results obtained from a single trajectory (i.e., the dimer trajectory is also used for the monomer analysis) and 2 trajectories (i.e., separate trajectories are used for the monomer and dimer) are similar. Proteins 2005. © 2005 Wiley‐Liss, Inc.
A graph spectral analysis of the structural similarity network of protein chains
Authors: Krishnadev O. , Brinda K.V. , Vishveshwara Saraswathi
Published: August 2005

We present a simple method for the analysis of large networks based on their graph spectral properties. One of the advantages of this method is that it uses a single numerical computation to identify subclusters in a connected graph, which can significantly simplify the complexity involved in analyzing large graphs. This is illustrated using a network of protein chains constructed on the basis of their structural similarities. The large‐scale network properties and the cluster and subcluster organization of the protein chain network are presented. We summarize the results of structural and functional analyses of the nodes present in these clusters and elucidate the implications of structural similarity in the protein chain universe. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Crystal structure and structural stability of acylphosphatase from hyperthermophilic archaeon Pyrococcus horikoshii OT3
Authors: Miyazono Ken‐ichi , Sawano Yoriko , Tanokura Masaru
Published: August 2005

To elucidate the structural basis for the high stability of acylphosphatase (AcP) from Pyrococcus horikoshii OT3, we determined its crystal structure at 1.72 Å resolution. P. horikoshii AcP possesses high stability despite its approximately 30% sequence identity with eukaryotic enzymes that have moderate thermostability. The overall fold of P. horikoshii AcP was very similar to the structures of eukaryotic counterparts. The crystal structure of P. horikoshii AcP shows the same fold βαββαβ topology and the conserved putative catalytic residues as observed in eukaryotic enzymes. Comparison with the crystal structure of bovine common‐type AcP and that of D. melanogaster AcP (AcPDro2) as representative of eukaryotic AcP revealed some significant characteristics in P. horikoshii AcP that likely play important roles in structural stability: (1) shortening of the flexible N‐terminal region and long loop; (2) an increased number of ion pairs on the protein surface; (3) stabilization of the loop structure by hydrogen bonds. In P. horikoshii AcP, two ion pair networks were observed one located in the loop structure positioned near the C‐terminus, and other on the β‐sheet. The importance of ion pairs for structural stability was confirmed by site‐directed mutation and denaturation induced by guanidium chloride. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Simulation of oligopeptide dynamics and folding. The use of NMR chemical shifts to analyse the MD trajectories
Authors: Busetta Bernard , Picard Philippe , Précigoux Gilles
Published: August 2005

In this paper, a simulation of the folding process, based on a random perturbations of the ϕ, ψ, χ1 dihedral angles, is proposed to approach the formation at the atom level of both principal elements of protein secondary structure, the α‐helix and the β‐hairpin structures. Expecting to understand what may happen in solution during the formation of such structures, the behaviour of large sets of random conformations that are generated for small oligopeptides was analysed. Different factors that may influence the folding (as conformational propensity, hydrophobic interactions and side‐chain mobility) were investigated. The difference between the corresponding theoretical folding and the real conformational diversity that is observed in solution is appraised by a comparison between the calculated and observed NMR secondary chemical shifts. From this study it appears that hydrophobic interactions and mobility represent the principal factors that initiate folding and determine the observed hydrogen‐bond pattern, which subsequently allows packing between the peptide side chains. Copyright © 2005 European Peptide Society and John Wiley & Sons, Ltd.
Non‐linear dynamical effects in semiconductor microcavities
Authors: Staehli J. L. , Kundermann S. , Saba M. , Ciuti C. , Baas A. , Guillet T. , Deveaud B.
Published: August 2005

An investigation of the parametric amplification and its coherent control in a semiconductor microcavity is presented. The time and angle resolved pump and probe experiments show that several picoseconds after pumping the polaritons are still coherent and parametric scattering is still going on. The experimental data concerning the time integrated measurements are in qualitative agreement with the numerical data obtained from a relatively simple theoretical model based on three polarisation components, pump, probe, and idler. As for the dynamics of parametric amplification in real time, the measurements reveal that often stimulation is considerably delayed with respect to the arrival of pump and probe. Even though the observed dynamics is complex, our simple theoretical model permits to reproduce several of the experimental features. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Symbolic computation of conservation laws of nonlinear partial differential equations in multi‐dimensions
Authors: Hereman Willy
Published: August 2005

A direct method for the computation of polynomial conservation laws of polynomial systems of nonlinear partial differential equations (PDEs) in multi‐dimensions is presented. The method avoids advanced differential‐geometric tools. Instead, it is solely based on calculus, variational calculus, and linear algebra. Densities are constructed as linear combinations of scaling homogeneous terms with undetermined coefficients. The variational derivative (Euler operator) is used to compute the undetermined coefficients. The homotopy operator is used to compute the fluxes. The method is illustrated with nonlinear PDEs describing wave phenomena in fluid dynamics, plasma physics, and quantum physics. For PDEs with parameters, the method determines the conditions on the parameters so that a sequence of conserved densities might exist. The existence of a large number of conservation laws is a predictor of complete integrability. The method is algorithmic, applicable to a variety of PDEs, and can be implemented in computer algebra systems such as Mathematica, Maple, and REDUCE. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Transient stability of DFIG wind turbines at an external short‐circuit fault
Authors: Sun Tao , Chen Zhe , Blaabjerg Frede
Published: August 2005

The fast development of wind power generation brings new requirements for wind turbine integration into the network. After clearance of an external short‐circuit fault, grid‐connected wind turbines should restore their normal operation without power loss caused by disconnections. This article concentrates on the transient stability of variable speed wind turbines with doubly fed induction generators (DFIGs) at an external short‐circuit fault. A simulation model of a MW‐level variable speed wind turbine with a DFIG developed in PSCAD/EMTDC is presented and the control and protection schemes are described in detail. The transient process of grid‐connected wind turbines with DFIGs at an external short‐circuit fault is analysed, and in critical post‐fault situations a measure is proposed for the voltage recovery of DFIG wind turbines after fault clearance. Simulation results demonstrate that in uncritical post‐fault situations the control schemes are able to restore the wind turbine's normal operation without disconnections. It is also proved that the proposed measure is effective in re‐establishing the voltage at the wind turbine terminal in critical post‐fault situations. Copyright © 2005 John Wiley & Sons, Ltd.
Association of the Primary Tumor Location with the Site of Tumor Recurrence after Curative Resection of Thoracic Esophageal Carcinoma
Authors: Doki Yuichiro , Ishikawa Osamu , Takachi Ko , Miyashiro Isao , Sasaki Yo , Ohigashi Hiroaki , Murata Kohei , Yamada Terumasa , Noura Shingo , Eguchi Hidetoshi , Kabuto Toshiyuki , Imaoka Shingi
Published: August 2005

The site of surgical failure in cases of thoracic esophageal cancer (TEC) may be affected by the vertical location of the cancer in this longitudinal organ, suggesting the need to select the mode of adjuvant therapy based on location. We classified 501 TECs (92% squamous cell carcinomas) that underwent curative surgery without preoperative treatment as 13% upper thoracic (Ut), 51% middle thoracic (Mt), and 36% lower thoracic (Lt) lesions. Recurrent disease was discovered in 180 (36%) of the patients during a postoperative survey, most frequently in the cervical nodes (19%), liver (18%), abdominal paraaortic nodes (17%), and upper mediastinal nodes (17%). Although postoperative survival rates were similar (5‐year survival: Ut 51%, Mt 55%, Lt 54%), the tumor recurrence site was significantly affected by the TEC vertical location, with recurrence in the cervical and upper mediastinal nodes being most frequent for Ut and Mt cases and in the liver and abdominal paraaortic nodes for Lt cases. Insufficient surgical lymph node clearance could be assessed by the recurrence index (RI), defined as the frequency of metastasis at recurrence divided by that at surgery. The RI was significantly lower for the upper abdominal nodes (4%, 8/184) than the lower mediastinal nodes (15%, 19/123) or the upper mediastinal nodes (19%, 30/154). These findings indicated that regional tumor recurrence, corresponding to the surgical field, was more frequent in the Ut and Mt cases (53% and 51%) than the Lt cases (18%); and distant recurrence was more frequent in the Lt cases (62%) than in Ut or Mt cases (25% and 36%). Thus the vertical location of the thoracic esophageal cancer can be said to affected strongly the site of tumor recurrence after curative surgery. Regional radiotherapy might be expected to have an adjuvant effect on Ut/Mt tumors and systemic chemotherapy on Lt tumors.
Appraisal of Surgical Treatment for Pulmonary Metastasis from Hepatocellular Carcinoma
Authors: Nakajima Jun , Tanaka Makoto , Matsumoto Jun , Takeuchi Eriho , Fukami Takeshi , Takamoto Shinichi
Published: August 2005

The outcome of pulmonary metastasectomy of hepatocellular carcinoma (HCC) was appraised in this study. Twenty patients with pulmonary metastasis from HCCs undergoing pulmonary resection between 1990 and 2003 were included in this study. They had undergone curative treatment for the primary lesion and were candidates for a pulmonary metastasectomy for complete resection. Among the 20 patients, 13 died: 5 from hepatic failure, 5 from respiratory failure, and 2 from brain metastasis due to recurrence of the HCC. One patient died from cardiac failure without HCC recurrence. At the latest observation, three of the seven survivors were doing well without HCC recurrence, and others survived with recurrence. The overall survival rates after the initial lung surgery were 45.3% at 1 year and 23.8% at 3 years, respectively. The survival rates without recurrence were 32.4% at 1 year and 21.6% at 3 years, respectively. A Kaplan‐Meier analysis showed that multiple lung surgeries and a negative histologic finding of the liver cut surface were favorable characteristics for survival without recurrence. In conclusion, the selected patients were Candidates for pulmonary metastasectomy after a curative hepatectomy for HCC and could benefit from the complete resection. Also, repeated pulmonary resections through thoracoscopy could result in the long‐term survival of patients with pulmonary recurrence of HCC.
Usefulness of anti‐oxidized LDL antibody determination for assessment of clinical control in patients with heart failure
Authors: George Jacob , Wexler Dov , Roth Arie , Barak Tomer , Sheps David , Keren Gad
Published: August 2005

Background:

It has been suggested that oxidative stress may play a role in the pathogenesis of heart failure, this may have potential implications for therapeutic strategies. However, measures of oxidative stress are subject to confounding inaccuracies. IgG antibodies to oxidized LDL reflect exposure to the lipoprotein over an extended period and may thus mirror oxidative stress over a prolonged time frame. Therefore, we tested the hypothesis that anti‐oxLDL antibodies correlate with the control of heart failure (HF), as manifested by hospital admissions for cardiac dysfunction.

Methods:

One hundred and two consecutive patients attending the HF clinic with either systolic or diastolic HF were enrolled and the quality of clinical control was evaluated by assessing hospital admissions over the year prior to index determination of the oxidative stress marker. Antibodies to oxLDL were determined by ELISA and pro‐BNP levels were also measured.

Results:

Most patients (mean age 71.5 years) had systolic HF; mean NYHA functional class was 2.7 and mean left ventricular ejection fraction was 39.7%. Anti‐oxLDL antibodies, but not pro‐BNP, correlated significantly with mean NYHA score (averaged from all clinic visits in the year prior to blood testing), and with hospital admissions over the year prior to blood testing. Mean IgG anti‐oxLDL antibody levels in patients with hospital admissions were 3.4 times higher than those in subjects not hospitalized over the previous year.

Conclusion:

IgG anti‐oxLDL antibody levels correlate with the severity of HF.
Computer simulations of successful defibrillation in decoupled and non-uniform cardiac tissue
Authors: Kuijpers N. H. L. , Keldermann R. H. , Arts T. , Hilbers P. A. J.
Published: August 2005

Aim

The aim of the present study is to investigate the origin and effect of virtual electrode polarization in uniform, decoupled and non-uniform cardiac tissue during field stimulation.

Methods

A discrete bidomain model with active membrane behaviour was used to simulate normal cardiac tissue as well as cardiac tissue that is decoupled due to fibrosis and gap junction remodelling. Various uniform and non-uniform electric fields were applied to the external domain of uniform, decoupled and non-uniform resting cardiac tissue as well as cardiac tissue in which spiral waves were induced.

Results

Field stimulation applied on non-uniform tissue results in more virtual electrodes compared with uniform tissue. The spiral waves were terminated in decoupled tissue, but not in uniform, homogeneous tissue. By gradually increasing local differences in intracellular conductivities, the amount and spread of virtual electrodes increased and the spiral waves were terminated.

Conclusion

Fast depolarization of the tissue after field stimulation may be explained by intracellular decoupling and spatial heterogeneity present in normal and pathological cardiac tissue. We demonstrated that termination of spiral waves by means of field stimulation can be achieved when the tissue is modelled as a non-uniform, anisotropic bidomain with active membrane behaviour.
The yeaS (leuE) gene of Escherichia coli encodes an exporter of leucine, and the Lrp protein regulates its expression
Authors: Kutukova Ekaterina A. , Livshits Vitaliy A. , Altman Irina P. , Ptitsyn Leonid R. , Zyiatdinov Michael H. , Tokmakova Irina L. , Zakataeva Natalia P.
Published: August 2005

Overexpression of the yeaS gene encoding a protein belonging to the RhtB transporter family conferred upon cells resistance to glycyl‐l‐leucine, leucine analogues, several amino acids and their analogues. yeaS overexpression promoted leucine and, to a lesser extent, methionine and histidine accumulation by the respective producing strains. Our results indicate that yeaS encodes an exporter of leucine and some other structurally unrelated amino acids. The expression of yeaS (renamed leuE for “leucine export”) was induced by leucine, l‐α‐amino‐n‐butyric acid and, to a lesser extent, by several other amino acids. The global regulator Lrp mediated this induction.
The hiddenness argument revisited (II)
Authors: SCHELLENBERG J. L.
Published: August 2005

In this second of two essays responding to critical discussion of my Divine Hiddenness and Human Reason, I show how an ‘accommodationist’ strategy can be used to defuse objections that were not exposed as irrelevant by the first essay. This strategy involves showing that the dominant concern of reasons for divine withdrawal can be met or accommodated within the framework of divine–human relationship envisaged by the hiddenness argument. I conclude that critical discussion leaves the argument very much alive and kicking, and indeed strengthened as it moves into its second decade of life.
Channeling of red and green cone inputs to the zebrafish optomotor response
Authors: ORGER MICHAEL B. , BAIER HERWIG
Published: August 2005

Visual systems break scenes down into individual features, processed in distinct channels, and then selectively recombine those features according to the demands of particular behavioral tasks. In primates, for example, there are distinct pathways for motion and form processing. While form vision utilizes color information, motion pathways receive input from only a subset of cone photoreceptors and are generally colorblind. To explore the link between early channeling of visual information and behavioral output across vertebrate species, we measured the chromatic inputs to the optomotor response of larval zebrafish. Using cone-isolating gratings, we found that there is a strong input from both red and green cones but not short-wavelength cones, which nevertheless do contribute to another behavior, phototaxis. Using a motion-nulling method, we measured precisely the input strength of gratings that stimulated cones in combination. The fish do not respond to gratings that stimulate different cone types out of phase, but have an enhanced response when the cones are stimulated together. This shows that red and green cone signals are pooled at a stage before motion detection. Since the two cone inputs are combined into a single ‘luminance’ channel, the response to sinusoidal gratings is colorblind. However, we also find that the relative contributions of the two cones at isoluminance varies with spatial frequency. Therefore, natural stimuli, which contain a mixture of spatial frequencies, are likely to be visible regardless of their chromatic composition.