bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Investigations on the Influence of the Concentration of Polyacrylamide Solutions on Elongational Flow Behavior
Authors: Wilkes C. , Gampert B.
Published: April 2005

Information about the elongational flow behavior of dilute polymer solutions was obtained, which allows conclusions to be formulated about the extension of polymers and the elastic characteristics of such systems. It is shown that dilute polyacrylamide solutions, which show Newtonian behavior concerning the shear viscosity, can show elastic properties in elongational flow experiments.
Homochiral Conglomerates and Racemic Crystals in Two Dimensions: Tartaric Acid on Cu(110)
Authors: Romer Sara , Behzadi Bahar , Fasel Roman , Ernst Karl‐Heinz
Published: April 2005

Two‐dimensional lattice structures formed by racemic tartaric acid on a single crystalline Cu(110) surface have been studied and compared with the enantiopure lattices. At low coverage, the doubly deprotonated bitartrate species is separated into two‐dimensional conglomerates showing opposite enantiomorphism. At higher coverage, however, a singly deprotonated monotartrate species forms a heterochiral, racemic crystal lattice. While the enantioseparated bitartrate system undergoes decomposition at the same temperature as the enantiopure system, the racemic monotartrate lattice has a lower thermal stability than the enantiopure lattice of identical periodicity and surface density. At monolayer saturation coverage, the pure enantiomers form a denser lattice than the racemate. This is in contrast to the three‐dimensional tartaric acid crystals, where the racemate crystallizes in a lattice of higher density, which is also more thermally stable than the enantiopure tartaric acid crystals.
Acid–Base and Metal‐Ion Binding Properties of the RNA Dinucleotide Uridylyl‐(5′→3′)‐[5′]uridylate (pUpU3−)
Authors: Knobloch Bernd , Suliga Danuta , Okruszek Andrzej , Sigel Roland K. O.
Published: April 2005

It is well known that Mg2+ and other divalent metal ions bind to the phosphate groups of nucleic acids. Subtle differences in the coordination properties of these metal ions to RNA, especially to ribozymes, determine whether they either promote or inhibit catalytic activity. The ability of metal ions to coordinate simultaneously with two neighboring phosphate groups is important for ribozyme structure and activity. However, such an interaction has not yet been quantified. Here, we have performed potentiometric pH titrations to determine the acidity constants of the protonated dinucleotide H2(pUpU)−, as well as the binding properties of pUpU3− towards Mg2+, Mn2+, Cd2+, Zn2+, and Pb2+. Whereas Mg2+, Mn2+, and Cd2+ only bind to the more basic 5′‐terminal phosphate group, Pb2+, and to a certain extent also Zn2+, show a remarkably enhanced stability of the [M(pUpU)]− complex. This can be attributed to the formation of a macrochelate by bridging the two phosphate groups within this dinucleotide by these metal ions. Such a macrochelate is also possible in an oligonucleotide, because the basic structural units are the same, despite the difference in charge. The formation degrees of the macrochelated species of [Zn(pUpU)]− and [Pb(pUpU)]− amount to around 25 and 90 %, respectively. These findings are important in the context of ribozyme and DNAzyme catalysis, and explain, for example, why the leadzyme could be selected in the first place, and why this artificial ribozyme is inhibited by other divalent metal ions, such as Mg2+.
Cyanide‐Bridged Vitamin B12–Cisplatin Conjugates
Authors: Mundwiler Stefan , Spingler Bernhard , Kurz Philipp , Kunze Susanne , Alberto Roger
Published: April 2005

cis‐[PtCl(OH2)(NH3)2]+, the monoactivated form of cisplatin, reacts with the cyano ligand of cobalt in vitamin B12 (cyanocobalamin) to form a CoCNPt conjugate (1). Compound 1 is prepared in good yield directly in aqueous solution. The remaining chloride ligand of PtII is labile. It hydrolyzes slowly in aqueous solution and can be exchanged by stronger coordinating ligands, such as 9‐methylguanine or 2′‐deoxyguanosine, to yield vitamin B12–nucleobase conjugates. X‐ray structures of the vitamin B12–cisplatin conjugate 1 as well as of the product with coordinated 9‐methylguanine (2) are presented. The coordination geometry at PtII is almost perfectly square‐planar. The structure of the cobalamin compound remains essentially unchanged when compared with the original B12 structure. The guanine moiety of compound 2 binds in a 45° angle to the cisplatin molecule and interacts with neighboring molecules by means of π stacking and hydrogen bonds.
Self‐Supported Heterogeneous Titanium Catalysts for Enantioselective Carbonyl–Ene and Sulfoxidation Reactions
Authors: Wang Xisheng , Wang Xingwang , Guo Hongchao , Wang Zheng , Ding Kuiling
Published: April 2005

A new strategy for the heterogenization of chiral titanium complexes was developed by the in situ assembly of bridged multitopic BINOL ligands with [Ti(OiPr)4] without using a support. The assembled heterogeneous catalysts (self‐supported) showed excellent enantioselectivity in both the carbonyl–ene reaction of α‐methylstyrene with ethyl glyoxylate (up to 98 % ee) and the oxidation of sulfides (up to >99 % ee). The catalytic performance of these heterogeneous catalytic systems was comparable or even superior to that attained with their homogeneous counterparts. The spacers between the two BINOL units of the ligands in the assembled catalysts had significant impact on the enantioselectivity of the carbonyl–ene reaction. This demonstrates the importance of the supramolecular structures of the assemblies on their catalytic behavior. In the catalysis of sulfoxidation, the self‐supported heterogeneous titanium catalysts were highly stable and could be readily recycled and reused for over one month (at least eight cycles) without significant loss of activity and enantioselectivity (up to >99.9 % ee). The features of these self‐supported catalysts, such as facile preparation, robust chiral structure of solid‐state catalysts, high density of the catalytically active units in the solids, as well as easy recovery and simple recycling, are particularly important in developing methods for the synthesis of optically active compounds in industrial processes.
Nuclear factor kappa B activation is a potential target for preventing pancreatic carcinoma by aspirin
Authors: Sclabas Guido M. , Uwagawa Tadashi , Schmidt Christian , Hess Kenneth R. , Evans Douglas B. , Abbruzzese James L. , Chiao Paul J.
Published: April 2005

BACKGROUND

Pancreatic carcinoma exhibits a unique genetic profile of mutations that may play key roles in its progression to malignant phenotypes. Constitutive activation of transcription factor nuclear factor kappa B (NF‐κB) is a frequent molecular alteration in pancreatic carcinoma, suggesting a possible link between inflammation and cancer. The aims of the current study were to determine the effects of aspirin on pancreatic carcinoma prevention and to reveal a possible mechanism of aspirin‐mediated cancer chemoprevention.

METHODS

An orthotopic mouse model with human pancreatic carcinoma cell lines PANC‐1, PANC‐1/Puro, and PANC‐1/IκBαM was used to study the inhibitory effects of aspirin on pancreatic tumor formation.

RESULTS

Aspirin inhibited constitutive NF‐κB activity in culture and, in turn, decreased the expression of the NF‐κB downstream target gene, Cox‐2, in PANC‐1 or PANC‐1/Puro cells, without significantly inhibiting the in vitro growth of PANC‐1/Puro cells. All animals inoculated with either PANC‐1 or PANC‐1/Puro cells, and not given aspirin, developed pancreatic tumors, whereas none of the mice injected with PANC‐1/IκBαM cells showed any evidence of pancreatic tumor formation. Animals given aspirin for 6 days before, or at the time of, orthotopic tumor cell injection showed a significantly lower incidence of tumor formation compared with those receiving aspirin 2 weeks after inoculation and controls receiving no aspirin.

CONCLUSIONS

Aspirin repressed tumor formation by PANC‐1 cells in vivo in a prophylactic setting, suggesting a possible mechanism for aspirin's preventive effect in pancreatic carcinoma through inhibition of NF‐κB activation and a mechanistic link between inflammation and tumorigenesis. Aspirin‐mediated antiinflammatory approaches might be an effective strategy to prevent pancreatic carcinoma. Cancer 2005. © 2005 American Cancer Society.
Species and sex differences in brain distribution of corticotropin‐releasing factor receptor subtypes 1 and 2 in monogamous and promiscuous vole species
Authors: Lim Miranda M. , Nair Hemanth P. , Young Larry J.
Published: April 2005

Corticotropin‐releasing factor (CRF) receptor subtypes 1 and 2 have been implicated in rodent models of anxiety, but much less is known about the CRF system and social behavior. Both corticosterone and central CRF receptors modulate pair bonding in the monogamous prairie vole. Using receptor autoradiography, we mapped CRFR1 and CRFR2 in the brains of two monogamous vole species, the prairie vole and pine vole, and two promiscuous vole species, the meadow vole and montane vole. We found markedly different patterns of brain CRFR1 and CRFR2 binding among the four species, including species differences in the olfactory bulb, nucleus accumbens, lateral septum, hippocampus, laterodorsal thalamus, cingulate cortex, superior colliculus, and dorsal raphe. Interestingly, we also observed striking sex differences in voles: CRFR2 binding was higher in the encapsulated bed nucleus of the stria terminalis in males than females for all four vole species. These results suggest possible sites of action for CRF‐induced facilitation of pair bond formation in prairie voles, as well as potential sex differences in the CRF modulation of pair bonding. Further examination of CRF receptors in vole species may reveal a novel role for CRF in social behavior. Ultimately, our results identify several brain regions with conserved CRF receptor patterns across rodent and primate species, in contrast to several brain regions with phylogenetically plastic CRF receptor patterns, and have interesting implications for the evolution of CRF receptor patterns and behavior. J. Comp. Neurol. 487:75–92, 2005. © 2005 Wiley‐Liss, Inc.
Critical review of oral drug treatments for diabetic neuropathic pain—clinical outcomes based on efficacy and safety data from placebo‐controlled and direct comparative studies
Authors: Adriaensen Hugo , Plaghki Léon , Mathieu Chantal , Joffroy Alfred , Vissers Kris
Published: April 2005

The present review aims to evaluate the efficacy and safety of a selection of oral treatments for the management of painful diabetic neuropathy. A literature review was conducted retrieving placebo‐controlled and direct comparative studies with a selection of oral treatments for painful diabetic neuropathy. All studies were analyzed with regard to efficacy and tolerability. Efficacy was evaluated as the percentage improvement in pain intensity between baseline and endpoint. Tolerability was evaluated by means of study discontinuations due to adverse events and by incidence of drug‐related adverse events.

The analyzed trials enrolled different patient populations with mostly small numbers of patients. The great variability in dosages and dose titration schemes, cross‐over designs with variable wash‐out periods, and other design schemes made comparison between the different studies difficult. Gabapentin, lamotrigine, tramadol, oxycodone, mexiletine, and acetyl‐L‐carnitine were the only treatments studied in large (at least 100 patients), placebo‐controlled parallel group trials.

It is concluded that standardization in design and reporting for comparison of treatments is needed. Validated questionnaires for evaluation of the efficacy and safety should be further developed. Based on the reviewed randomised controlled trials, gabapentin shows good efficacy, a favourable side‐effect profile with lack of drug interactions and therefore it may be a first choice treatment in painful diabetic neuropathy, especially in the elderly. However, head to head trials of current treatments are lacking and therefore randomized controlled trials are required to address this issue. Copyright © 2005 John Wiley & Sons, Ltd.
Embryonic staging system for the short‐tailed fruit bat, Carollia perspicillata, a model organism for the mammalian order Chiroptera, based upon timed pregnancies in captive‐bred animals
Authors: Cretekos Chris J. , Weatherbee Scott D. , Chen Chih‐Hsin , Badwaik Nilima K. , Niswander Lee , Behringer Richard R. , Rasweiler John J.
Published: April 2005

There are approximately 4,800 extant species of mammals that exhibit tremendous morphological, physiological, and developmental diversity. Yet embryonic development has been studied in only a few mammalian species. Among mammals, bats are second only to rodents with regard to species number and habitat range and are the most abundant mammals in undisturbed tropical regions. Bat development, though, remains relatively unstudied. Here, we describe and illustrate a staging series of embryonic development for the short‐tailed fruit bat, Carollia perspicillata, based on embryos collected at timed intervals after captive matings. As Carollia can be readily maintained and propagated in captivity and is extremely abundant in the wild, it offers an attractive choice as a chiropteran model organism. This staging system provides a framework for studying Carollia embryogenesis and should prove useful as a guide for embryological studies of other bat species and for comparisons with other orders of mammals. Developmental Dynamics 233:721–738, 2005. © 2005 Wiley‐Liss, Inc.
Comparative expression analysis of transcription factor genes in the endostyle of invertebrate chordates
Authors: Hiruta Jin , Mazet Francoise , Yasui Kinya , Zhang Peijun , Ogasawara Michio
Published: April 2005

The endostyle of invertebrate chordates is a pharyngeal organ that is thought to be homologous with the follicular thyroid of vertebrates. Although thyroid‐like features such as iodine‐concentrating and peroxidase activities are located in the dorsolateral part of both ascidian and amphioxus endostyles, the structural organization and numbers of functional units are different. To estimate phylogenetic relationships of each functional zone with special reference to the evolution of the thyroid, we have investigated, in ascidian and amphioxus, the expression patterns of thyroid‐related transcription factors such as TTF‐2/FoxE4 and Pax2/5/8, as well as the forkhead transcription factors FoxQ1 and FoxA. Comparative gene expression analyses depicted an overall similarity between ascidians and amphioxus endostyles, while differences in expression patterns of these genes might be specifically related to the addition or elimination of a pair of glandular zones. Expressions of Ci‐FoxE and BbFoxE4 suggest that the ancestral FoxE class might have been recruited for the formation of thyroid‐like region in a possible common ancestor of chordates. Furthermore, coexpression of FoxE4, Pax2/5/8, and TPO in the dorsolateral part of both ascidian and amphioxus endostyles suggests that genetic basis of the thyroid function was already in place before the vertebrate lineage. Developmental Dynamics 233:1031–1037, 2005. © 2005 Wiley‐Liss, Inc.
Second branchial arch lineages of the middle ear of wild‐type and Hoxa2 mutant mice
Authors: O'Gorman Stephen
Published: April 2005

Our current understanding of the evolution of the mammalian middle ear was first suggested by embryological studies from the 19th century. Here, site‐specific recombinase‐mediated lineage tracing was used to define the second branchial arch contribution to the middle ear of wild‐type and Hoxa‐2 mutant embryos. The processus brevis of the malleus was found to arise from second arch tissues, making it the likely homologue of the retroarticular process of nonmammalian tetrapods. The second arch also formed a portion of the otic capsule. In light of avian lineage studies, second arch cells were probably incorporated into the otic capsule before avian and mammalian lineages diverged. In Hoxa2 mutant embryos, middle ear skeletal duplications occurred at sites where first and second arch elements are normally apposed. The dorsoventral positions at which second arch skeletal elements formed and the early migration of second arch neural crest cells were not altered by the absence of Hoxa2 function. Developmental Dynamics 234:124–131, 2005. © 2005 Wiley‐Liss, Inc.
Preparation and Characterization of Ag@TiO2 Core‐Shell Nanoparticles in Water‐in‐Oil Emulsions
Authors: Zhang Dan , Song Ximing , Zhang Rongwei , Zhang Ming , Liu Fengqi
Published: April 2005

We report a simple route for the effective synthesis of Ag@TiO2 nanoparticles in water‐in‐oil (w/o) emulsions and provide detailed characterization of the materials with TEM, TG‐DTA, IR, XRD, and SPS measurements. Such core‐shell hybrid nanoparticles can be fabricated in two simple steps: the formation of the silver core by the reduction of a Tollens reagent with glucose in the water phase, and the hydrolysis of Ti(OC4H9)4 at the water/oil interface for the formation of the amorphous TiO2 shell. The procedure led to the formation of nanocomposites with a crystalline core in a size range from 5 to 15 nm in diameter and an amorphous shell of 6–10 nm thickness in a typical synthesis. The shell was converted to crystalline oxide upon thermal treatment. Surface photovoltaic spectroscopy (SPS) measurements indicate that the materials have potential for application in photoinduced electron storage and photocatalysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Titanium Triamidotriamine Compounds: Syntheses, Structures and Redox Properties
Authors: Martins Ana M. , Ascenso José R. , de Azevedo Cristina G. , Dias Alberto R. , Duarte M. Teresa , Ferreira Humberto , Ferreira M. João , Henriques Rui T. , Lemos M. Amélia , Li Li , da Silva João F.
Published: April 2005

The preparation of 1,4,7‐{NH(2‐C6H4F)SiMe2}3‐1,4,7‐triazacyclononane (H3N3‐F[9]N3) and 1,4,8‐{N(H)PhSiMe2}3‐1,4,8‐triazacycloundecane (H3N3[11]N3), and their sodium derivatives Na3N3‐F[9]N3(THF)2 and Na3N3[11]N3(THF)2, is described. The reaction of [TiCl3(THF)3] with Na3N3‐F[9]‐N3(THF)2 and Na3N3[11]N3(THF)2 leads to [Ti{N3‐F[9]N3}] and [Ti{N3[11]N3}]. The titanium complexes react readily with I2 to give the TiIV derivatives [Ti{N3‐F[9]N3}]I and [Ti{N3[11]N3}]I. All titanium compounds display distorted trigonal prismatic geometries where the metal is coordinated to the six nitrogen donors. Fluxional processes that convert the conformations of the five‐ and six‐membered metallacycles and the Δ and Λ enantiomers of [Ti{N3[11]N3}]I have been identified in solution. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Highly Active Neutral Nickel(II) Complexes Bearing P,N‐Chelate Ligands: Synthesis, Characterization and Their Application to Addition Polymerization of Norbornene
Authors: Wang Hai‐Yu , Jin Guo‐Xin
Published: April 2005

Neutral nickel(II) complexes [[R–NP]NiPh(PPh3)](1, R = H; 2, R = CH3) bearing P,N‐chelate ligands ([H–NP] = (2‐diphenylphosphanyl)benzenamine L1; [CH3–NP] = (2‐diphenylphosphanyl) N‐methylbenzenamine L2) have been synthesized and characterized. The molecular structure of complex 1 has been confirmed by single‐crystal X‐ray analyses. Afteractivation with methylaluminoxane (MAO), catalytic precursors 1 and 2 could polymerize norbornene to afford addition‐type polynorbornene (PNB) with very high activities (4.43 × 107 g‐PNB mol–1‐Ni h–1), high molecular weight Mw (3.07 × 106 g mol–1) and moderate molecular weight distribution Mw/Mn. Catalytic activities, polymer yield, Mw and Mw/Mn of PNB have been investigated under various reaction conditions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Acidities of Nitrous and Nitric Acids
Authors: Exner Otto , Böhm Stanislav
Published: April 2005

The energies of nitrous and nitric acid and their anions were calculated at the MP2(FC)/6‐311++G(2d,2p) level. Their acidity was related to the acidity of hydroxylamine derivatives using isodesmic reactions. This procedure reveals that the molecules of HNO2 and HNO3 are strongly stabilized (by 119 or 206 kJ·mol–1, respectively) but their anions are stabilized even more (by 282 or 428 kJ·mol–1). The acidity of these acids is thus caused by the low energy of their anions and not by the high energy of the acid molecules, similarly to the case of carboxylic acids. This stability may be partly due to resonance but the contribution of this effect can only be estimated. Correlation of the acidities of various acids with the inductive and polarization parameters led to the following estimate: in the case of nitrous acid 46 % of the acidity enhancement is due to resonance while in the case of nitric acid it is 25 %. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Catalytic Properties and the Role of Copper in Bovine and Lentil Seedling Copper/Quinone‐Containing Amine Oxidases: Controversial Opinions
Authors: Agostinelli Enzo , Belli Francesca , Dalla Vedova Laura , Longu Silvia , Mura Anna , Floris Giovanni
Published: April 2005

In this microreview, the differences in the catalytic cycle of two copper/quinone‐containing amine oxidases, one from lentil seedlings, representative of plant enzymes, and the other from bovine serum, typical of mammalian enzymes, are discussed. Although both enzymes are involved in the control of the levels of mono‐, di‐, and polyamines, and contain the same organic cofactor, the quinone of 2,4,5‐trihydroxyphenylalanine, known as TOPA or TPQ, lentil amine oxidase operates in a different way and with a much higher catalytic activity than the bovine serum enzyme. The role of copper in the two enzymes is also discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Analysis of lidar fields using local polynomial regression
Authors: Lindström Torgny , Holst Ulla , Weibring Petter
Published: April 2005

Lidar (light detection and ranging) is a laser based tool for remote measurement of several atmospheric species of importance. We consider the analysis of a field, consisting of several consecutive measurements, in which the concentrations are proportional to the derivatives in the directions of the light paths. Inference is based on local polynomial kernel regression, both for estimation of the derivatives of the mean‐function and for estimation of the variance‐function. Bivariate bandwidth matrices are selected using the empirical‐bias bandwidth selector (EBBS) adapted to allow for dependent data and to support selection of bivariate bandwidths. The estimation procedure is demonstrated on measurements of atomic mercury from the Solvay industries mercury cell chlor‐alkali plant in Rosignano Solvay, Italy. Copyright © 2005 John Wiley & Sons, Ltd.
Optimizing groundwater long‐term monitoring networks using Delaunay triangulation spatial analysis techniques
Authors: Ling Meng , Rifai Hanadi S. , Newell Charles J.
Published: April 2005

Groundwater long‐term monitoring (LTM) is a costly activity required at most subsurface remediation sites. Many existing LTM networks need to be optimized to reflect changes in site conditions and to increase their effectiveness in defining the plume. A spatial analysis method using Delaunay triangulation techniques was developed to eliminate redundant monitoring points and to locate new wells where additional data are needed. This method uses Delaunay triangulation of the monitoring network for site discretization and assesses the concentration estimation error at each monitoring location to judge its relative contribution to the spatial plume characterization. Locations where the concentration estimation error is small are considered redundant and become candidates for elimination. New monitoring locations are identified where the projected concentration estimation errors are high. Tests comparing the Delaunay method to a fate and transport analytical model illustrated the attributes and effectiveness of the method. Application to a benzene plume site demonstrated that results from Delaunay triangulation agree well with geostatistical approaches. Although the method is relatively less accurate, and lacks the resolution obtained with the geostatistical approach, it is computationally efficient and simple to implement by non‐statisticians. Copyright © 2005 John Wiley & Sons, Ltd.
Shore platform morphology on a rapidly uplifting coast, Wellington, New Zealand
Authors: Kennedy D. M. , Beban J. G.
Published: April 2005

The coast of Wellington, New Zealand, is tectonically active and contains a series of uplifted and contemporary shore platforms that are developed in Triassic Greywacke. The platform profiles are rugged with relief of metre scale common. The surveyed platforms were formed at, and at two distinct levels 1–1·5 and 2–2·5 m above, mean sea level. They range in width up to 70 m and are highly fractured with fracture densities in excess of 20[sol ]m2 common. The rate of development of these platforms is rapid, with lateral erosion rates of up to 0·15 m[sol ]yr calculated, allowing platform development to occur over centennial scales. Even given this rapid development, continued instantaneous uplift of the coast has meant they are unable to reach an equilibrium state, whereby the effectiveness of wave processes in removing material is reduced by platform extension. The co‐seismic uplift means that the rear of the platforms is raised beyond the limits of marine process and has become an area of deposition. Although no direct process measurements were made the highly fractured nature of the bedrock appears to play a major role in platform evolution, with wave processes being easily able to pluck blocks as evidenced by fresh erosion scars and active gravel beaches at the rear of many platforms. This coast therefore represents an extremely dynamic youthful shore platform environment, where the processes of marine abrasion can be observed over historical timescales. Copyright © 2005 John Wiley & Sons, Ltd.
Finite‐difference 4th‐order compact scheme for the direct numerical simulation of instabilities of shear layers
Authors: Jiang Yan , Floryan J. M.
Published: April 2005

An algorithm based on the 4th‐order finite‐difference compact scheme is developed and applied in the direct numerical simulations of instabilities of channel flow. The algorithm is illustrated in the context of stream function formulation that leads to field equation involving 4th‐order spatial derivatives. The finite‐difference discretization in the wall‐normal direction uses five arbitrarily spaced points. The discretization coefficients are determined numerically, providing a large degree of flexibility for grid selection. The Fourier expansions are used in the streamwise direction. A hybrid Runge–Kutta/Crank–Nicholson low‐storage scheme is applied for the time discretization. Accuracy tests demonstrate that the algorithm does deliver the 4th‐order accuracy. The algorithm has been used to simulate the natural instability processes in channel flow as well as processes occurring when the flow is spatially modulated using wall transpiration. Extensions to three‐dimensional situations are suggested. Copyright © 2005 John Wiley & Sons, Ltd.
UV‐Curable Cycloaliphatic Epoxide Based on Modified Linseed Oil: Synthesis, Characterization and Kinetics
Authors: Zou Kunrong , Soucek Mark D.
Published: April 2005

Summary: Linseed oil was derivitized with 1,3‐butadiene via a Diels‐Alder reaction. The cycloaddition adduct was then epoxidized using a hydrogen peroxide/quaternary ammonium tetrakis(diperoxotungsto) phosphate system. The cyclohexene derivitized linseed oil (CLO) and the epoxidized cyclohexene derivatized linseed oil (ECLO) were characterized by 1H NMR, 13C NMR, and FT‐IR. In addition, 2D NMR measurements (COSY) were performed on CLO and ECLO to identify the cyclohexyl structures. Molecular weight was determined by ESI‐MS and GPC. The ECLO was photo‐polymerized using UV‐light, and the kinetics of the photo‐curing reactions was evaluated by real‐time FT‐IR and photo‐DSC. All the characterizations supported the successful introduction of cyclohexyl structure to the backbone of linseed oil directly and indirectly. Real‐time FT‐IR and photo‐DSC indicated the slightly improved reactivity of ECLO.

Ideal structure of cyclohexene linseed oil (CLO).

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Ideal structure of cyclohexene linseed oil (CLO).
Synthesis and Liquid Crystalline Properties of Poly(ethylene oxide) Brushes with Amphiphilic Side Groups
Authors: Kim Jong‐Uk , Lee Jong‐Chan
Published: April 2005

Summary:Poly(ethylene oxide)s containing decylthiomethyl (DTP), decylsulfonylmethyl (DSP), methyl‐oligo(ethylene oxide) thiomethyl (MnOTP), methyl‐oligo(ethylene oxide) sulfonylmethyl (MnOSP), decyl‐oligo(ethylene oxide) thiomethyl (DnOTP), and decyl‐oligo(ethylene oxide) sulfonylmethyl (DnOSP) groups in the side‐chains, wheren(the number of ethylene oxide units) = 1, 2, 3, or 4 for DnOTP and DnOSP, andn = 2, 3, or 7 for MnOTP and MnOSP, were synthesized to study the effect of the structure of the side‐chains on the ordered phases of the polymers. All of the MnOSPs, as well as M2OTP and M3OTP, were found to be amorphous polymers. DTP, M7OTP, D1OTP, D2OTP, and D3OTP showed crystalline phases below their isotropic temperatures. DSP, D1OSP, D2OSP, D3OSP, D4OSP, and D4OTP were found to be liquid crystalline. Therefore, the phase separation facilitated by the introduction of the sulfone group and/or by the addition of the longer ethylene oxide units between the ethylene oxide backbones and the hydrophobic decyl tails was found to be a key factor in the formation of the liquid crystalline phases. These ordered phases were characterized using differential scanning calorimetry, polarized optical microscopy, and X‐ray diffraction.

Schematic illustration of the structures of poly(ethylene oxide) brushes showing liquid crystalline phases.

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Schematic illustration of the structures of poly(ethylene oxide) brushes showing liquid crystalline phases.
Confocal Raman Spectroscopy – Applications on Wood, Pulp, and Cellulose Fibres
Authors: Röder Thomas , Sixta Herbert
Published: April 2005

The manifold possibilities using dispersive Raman spectroscopy along the production chain from wood to cellulose fibre are presented here: The distribution of the lignin, cellulose, and added resins in the wood cell; additives inside regenerated cellulose fibres; their accessibility and reactivity. On‐line measurements during the phase transition of magnesium sulphite ‐hexahydrate into ‐trihydrate are performed in a stirring vessel.
Characterization of Water‐Soluble Cellulose Derivatives in Terms of the Molar Mass and Particle Size as well as Their Distribution
Authors: Kulicke W.‐M. , Clasen Christian , Lohman Claudia
Published: April 2005

The property profile of cellulose derivatives dissolved in aqueous solvents is not only dependent on the chemical composition (average‐, molar‐ or regiospecific degree of substitution, as well as the substitution along the chain), solvent, temperature and concentration but also on the molar mass and the particle size. All this information can be obtained from the Mark‐Houwink‐Sakurada‐relationship ([;gh]‐M‐) or the RG‐M‐relationship, if these are at hand. These relationships are suitable for a specific degree of substitution. The RG‐M‐relationship has only been determined and published for a few water‐soluble cellulose derivatives.

The prerequisite is the availability of a homologous series of samples with the same chemical composition. In this paper it is shown that only the ultrasonic degradation is able to create such a series.

Due to the ability of coupled methods of analysis to acquiring absolute data, molar mass and particle size distributions have been compiled in recent years. Using such methods it was possible to determine molar mass and particle size distributions of several aqueous cellulose derivative solutions by combining a fractionation unit (size exclusion chromatography (SEC) or flow field‐flow fractionation (FFFF)) with multi angle laser light scattering (MALLS) for the detection of Mw and RG and concentration detection (DRI). Results for nonionic cellulose ethers, mixed cellulose ethers, ionic carboxymethyl cellulose, sulfoethyl cellulose, hydrophobically modified hydroxyethyl cellulose were obtained and are partially discussed with focus on the recovery of cellulose derivates after fractionation and the impact on the distribution functions.
Studies on the Thermostability of Modified Lyocell Dopes
Authors: Wendler Frank , Meister Frank , Heinze Thomas
Published: April 2005

Modification of Lyocell dopes with special additives enables the creation of new innovative materials. Additives with functional groups and active surfaces may initiate complex chemical reactions in cellulose/N‐methylmorpholine‐N‐oxide monohydrate (NMMO) solutions. The effect of carboxylic groups on the thermostability was investigated by incorporating of sugar acids, acidic ion exchange resins (IER) and superabsorbing polymers (SAP) into the solutions. Whereas the sugar acids show strict correlations between the carboxyl group content in solution and onset temperature, viscosity reduction, coloration and by‐product formation, the additives show an induction time, which finally leads to accelerated degradation reactions. The cellulose/NMMO solutions were additionally characterized by means of UV/VIS spectroscopy.
Microscopic Visualization of Nanostructures of Cellulose Derivatives
Authors: Liebert Tim , Hornig Stephanie , Hesse Stephanie , Heinze Thomas
Published: April 2005

Microscopy has proved to be a valuable tool for the investigation of supermolecular structures of cellulose derivatives. Thus, with AFM it was possible to show that statistically functionalized derivatives (degree of substitution below 3) form specific aggregates called fringed micelles. In contrast, derivatives with a non‐statistic distribution exhibit a more network‐like structure as known for galactomannans consisting of block‐like structures. If samples are prepared by deposition of dilute solutions of polyelectrolytes on mica and drying at elevated temperature, the formation of nanorings is observed. In addition, AFM and REM were applied to investigate the morphology of membranes prepared of cellulose esters with unsaturated substituents. It was shown that cross‐linking of the polymer chains in the membranes does not lead to a change in the nanostructure of the surface, i.g., the surface roughness and the pore sizes were not modified.
Dynamic 13C NMR studies of ligand exchange in linear (d10) silver(I) and gold(I) and square‐planar (d8) rhodium(I) homoleptic metal carbonyl cations in superacidic media
Authors: Ahsen B. von , Bach C. , Balzer G. , Bley B. , Bodenbinder M. , Hägele G. , Willner H. , Aubke F.
Published: April 2005

The dynamic CO exchange of the monovalent metal carbonyl cations [Ag(13CO)]+, [Au(13CO)2]+–Au(13CO) SO3F and [Rh(12CO)4−x(13CO)x]+ (x⩽1) in superacidic solutions was studied by variable‐temperature 13C NMR methods. The exchange rates are strongly dependent on the acidity of the solvent, the concentration of metal carbonyl cations and temperature. Whereas a suitable exchange rate of the Ag(I) system is only accessible in magic acid (HSO3F–SbF5), the more stable Au(I) and Rh(I) systems were studied in the less acidic fluorosulfuric acid. Selected solutions of Ag(I), Rh(I) and Au(I) yielded activation barriers ΔG* of 42.7, 43.5, and 56.2 kJ mol−1 respectively. Copyright © 2005 John Wiley & Sons, Ltd.
Solid‐state NMR study of Schiff base derivatives of 2‐hydroxynaphthaldehyde. Deuterium isotope effects on 15N chemical shifts in the solid state
Authors: Rozwadowski Z. , Schilf W. , Kamieński B.
Published: April 2005

Schiff base derivatives of 2‐hydroxynaphthylaldehyde were studied by means of 13C and 15N cross‐polarization magic angle spinning NMR spectroscopy and deuterium isotope effects on 15N chemical shifts, ΔN(D), in the solid state. ΔN(D) in the solid state provided evidenced for the presence of a dynamic proton transfer equilibrium in the solid state at the room temperature. Copyright © 2005 John Wiley & Sons, Ltd.
On parallel machine replacement problems with general replacement cost functions and stochastic deterioration
Authors: Childress Suzanne , Durango‐Cohen Pablo
Published: April 2005

The parallel machine replacement problem consists of finding a minimum cost replacement policy for a finite population of economically interdependent machines. In this paper, we formulate a stochastic version of the problem and analyze the structure of optimal policies under general classes of replacement cost functions. We prove that for problems with arbitrary cost functions, there can be optimal policies where a machine is replaced only if all machines in worse states are replaced (Worse Cluster Replacement Rule). We then show that, for problems with replacement cost functions exhibiting nonincreasing marginal costs, there are optimal policies such that, in any stage, machines in the same state are either all kept or all replaced (No‐Splitting Rule). We also present an example that shows that economies of scale in replacement costs do not guarantee optimal policies that satisfy the No‐Splitting Rule. These results lead to the fundamental insight that replacement decisions are driven by marginal costs, and not by economies of scale as suggested in the literature. Finally, we describe how the optimal policy structure, i.e., the No‐Splitting and Worse Cluster Replacement Rules, can be used to reduce the computational effort required to obtain optimal replacement policies. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005
Poly(styrene–b–ethylene/butylene–b–styrene)/cobalt ferrite magnetic nanocomposites
Authors: Rajan Guru S. , Mauritz Kenneth A. , Stromeyer Stacy L. , Kwee Tety , Mani Prakash , Weston James L. , Nikles David E. , Shamsuzzoha Mohammad
Published: April 2005

Magnetic nanoparticles were created in or around the sulfonated (s) polystyrene domains in a poly[styrene–b–(ethylene–co–butylene)–b–styrene)] block copolymer (BCP) using an in situ inorganic precipitation procedure. The sBCP was neutralized with a mixed iron/cobalt chloride electrolyte, and the doped samples were converted to their oxides by reaction with sodium hydroxide. Transmission electron microscopy indicated the presence of nanoparticles having diameters of 20–50 nm. Metal oxide particle structures were studied using wide angle X–ray diffraction, which revealed that they were inverse spinel cobalt iron oxide crystals. Thermogravimetric analysis provided the weight percent of the inorganic component and nanocomposite thermal decomposition profile. Modulated differential scanning calorimetry studies suggested that the inorganic inclusions were selectively grown in the polystyrene hard block phase. These nanocomposites were shown, using alternating gradient magnetometry, to be ferrimagnetic at room temperature. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1475–1485, 2005
Correlated one‐electron wave functions
Authors: Weiner B. , Ortiz J. V.
Published: April 2005

A one‐electron theory of many‐electron systems that explicitly describes electron–electron correlation may be based on the observation that antisymmetrized geminal power (AGP) states are completely characterized by the occupation numbers of their first‐order reduced density operators (FORDO) and a set of canonical general spin–orbitals (CGSOs), which are in general distinct from the natural general spin–orbitals. Because the FORDO alone does not determine an AGP state, a density matrix functional may be defined. A generalization of the independent‐particle Fock operator serves to express the total state energy in terms of ionization energies, kinetic energies, and potential energies of the CGSOs. A one‐electron picture of chemical bonding emerges from this theory. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
US28 actions in HCMV infection: lessons from a versatile hijacker
Authors: Boomker J. M. , van Luyn M. J. A. , The T. H. , de Leij L. F. M. H. , Harmsen M. C.
Published: April 2005

Mimicking host proteins is a strategy adopted by several herpesviruses to exploit the host cell for their own benefit. In this respect the human cytomegalovirus (HCMV) chemokine receptor homologue US28, has been extensively studied. Molecular pirates such as US28 can teach us about crucial events in HCMV infection and may either offer a potential target for antiviral therapy or provide an alternative strategy to immune suppression. Despite elaborate research into the chemokine binding affinity, signalling properties, intracellular trafficking and expression kinetics of US28, a solid hypothesis about the role of US28 in HCMV infection has not yet been proposed. It appears that US28 may behave as a molecular pirate that employs smart strategies for cell entry, host gene regulation and immune evasion. This review will elaborate on these aspects of US28 biology and discuss possible implications for HCMV infection. Copyright © 2005 John Wiley & Sons, Ltd.
Cover Picture: Phase Separation Micromolding: A New Generic Approach for Microstructuring Various Materials (Small 6/2005)
Authors: Vogelaar Laura , Lammertink Rob G. H. , Barsema Jonathan N. , Nijdam Wietze , Bolhuis‐Versteeg Lydia A. M. , van Rijn Cees J. M. , Wessling Matthias
Published: April 2005

The cover picture shows a compilation of microstructures that were prepared by phase separation micromolding. The top three images depict examples of two porous microstructures and one that is completely dense. The bottom picture shows optical reflection, caused by a periodic microstructure on a mold, and two transparent replicas that are floating in nonsolvent after phase separation. For more information, please read the Full Paper "Phase Separation Micromolding: A New Generic Approach for Microstructuring Various Materials" by R. G. H. Lammertink and co‐workers on page 645 ff.
The role of ultrasound imaging in diagnosing and investigating early pregnancy failure
Authors: Jauniaux E. , Johns J. , Burton G. J.
Published: April 2005

The advent of high‐resolution transvaginal ultrasound (TVS) has revolutionized our understanding of the pathophysiology and the management of early pregnancy failure. Knowledge of the ultrasound appearances of normal early pregnancy development and a good understanding of its pitfalls are essential for the diagnosis and management of early pregnancy failure. Ultrasound imaging has rapidly replaced all other techniques used to study normal human development in the first trimester, and ultrasound features of the early gestational sac have corroborated anatomical studies showing that the first structures to appear are the celomic cavity and the secondary yolk sac. No single ultrasound measurement of the different anatomical features in the first trimester has been shown to have a high predictive value for determining early pregnancy outcome. Similarly, Doppler studies have failed to demonstrate abnormal blood flow indices in the first‐trimester uteroplacental circulation of pregnancies that subsequently end in miscarriage. Ultrasound parameters combined with maternal serum hormone levels, maternal age, smoking habits, obstetric history and the occurrence of vaginal bleeding have all been combined in multivariate analyses, with mixed results. Combined ultrasound and in‐vitro experiments have demonstrated that the maternal circulation inside the placenta starts at the periphery at around 9 weeks of gestation and that this is associated with a physiological oxidative stress which could be the trigger for the formation of the placental membranes. Abnormal development of these membranes can result in subchorionic hemorrhage and threatened miscarriage with subsequent long‐term consequences such as preterm rupture of the membranes and preterm labor, irrespective of the finding of a hematoma on ultrasound. In both euploid and aneuploid missed miscarriages there is clear ultrasound evidence for excessive entry of maternal blood at a very early stage inside the developing placenta resulting in oxidative stress and subsequent degeneration of villous tissue. The finding of blood flow in the intervillous space in cases of first‐trimester miscarriage using color Doppler also appears to be useful in the prediction of success of expectant management. Miscarriages with blood flow within the intervillous space are up to four times more likely to complete with expectant management. TVS is considered the gold standard in the diagnosis and management of incomplete miscarriage. Expectant management of miscarriage, using ultrasound parameters to determine eligibility, could significantly reduce the number of unnecessary evacuations of the retained products of conception, depending on the criteria used. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
Abundances of five parasitoids attacking the scale insectNipponaclerda biwakoensison morphologically changed reed shoots due to damage by a stem‐boring caterpillar
Authors: Kaneko Shuji
Published: April 2005

Abundances of the scale insectNipponaclerda biwakoensisand its five parasitoids per shoot of the common reed,Phragmites australis, were compared between shoots damaged by a stem‐boring caterpillar and undamaged shoots. Reed shoots that were damaged by the stem‐borer in spring change morphologically during summer, inducing tillers from the nodes beneath the damaged part. The number of female scales per shoot did not differ significantly between damaged and undamaged shoots in the second scale generation (September), but was significantly lower on damaged shoots in the third generation (November). Three parasitoid species attacking the scale exhibited different responses to the shoot damage, with the response by each parasitoid being constant in the two scale generations: the parasitism rate byAprostocetussp. per shoot was higher on damaged shoots, whereas that byAstymachus japonicuswas lower on damaged shoots, and no difference was detected forBoucekiella depressa. In the third scale generation, the parasitism rate by Encyrtidae sp. 1 showed no difference, with respect to shoot damage, whereas that by Encyrtidae sp. 2 was lower on damaged shoots. In three dominant parasitoids, shoot damage had no effect on the number of emerging adults per host, and the sex ratio and body size of the adults. The number of emerging adults per shoot differed significantly between damaged and undamaged shoots for four parasitoids, exceptB. depressa. These results suggest that shoot damage by the stem‐borer exerts a delayed negative impact on the scale numbers and affects the parasitism rate of the scales by three parasitoids and the emerging adult numbers of four parasitoids.
Gene expression profile of mechanically impacted bovine articular cartilage explants
Authors: Chan P. S. , Schlueter A. E. , Coussens P. M. , Rosa G. J. M. , Haut R. C. , Orth M. W.
Published: April 2005

Traumatic injury to a joint can initiate cartilage degradation. Blunt trauma increases matrix damage and decreases proteoglycan synthesis in in vitro models. Few studies have investigated gene expression of articular cartilage (AC) following mechanical loading. Recent advances in microarray technology allow analysis of a number of genes, and may elucidate pathways of AC degradation. In the present study, we used a bovine cDNA microarray to determine how acute trauma of cartilage explants in the absence of underlying bone alters gene expression. Results indicate that at least 19 genes were differentially expressed at 3 h after trauma. Fourteen genes were up‐regulated and five genes were down‐regulated relative to control explants. The up‐regulated genes included cytokine and chemokine receptors, enzymes, and molecules involved in signal transduction. Genes of adhesion molecules and apoptosis were down‐regulated. The results of this study highlight the potential benefits of using a bovine cDNA microarray to study cartilage metabolism. © 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.