bluuebunny/crossref_metadata_2025 huggingface dataset:
The Art of SPM: Scanning Probe Microscopy in Materials Science
Authors: Loos J.
Published: July 2005

In this Progress Report, outstanding scientific applications of scanning probe microscopy (SPM) in the field of materials science and the latest technique developments are introduced and discussed. Besides being able to image the organization of matter with sub‐nanometer resolution, SPM, owing to its basic operating principle, provides the power to measure, analyze, and even quantify properties of matter on the nanometer length scale. Moreover, because of its unique potential to manipulate the organization of atoms, molecules, assemblies, or particles and to structure surfaces in a controlled fashion, in the fields of nanoscience and nanotechnology SPM has become one of the most powerful tools for preparation and analysis of nanostructures and their functionality. Because of the tremendous variety of its applications, only selected—but subjectively exceptional—topics are considered in this Progress Report, showing the full potential of SPM.
Cover Picture: Long, Monomolecular Guanine‐Based Nanowires (Adv. Mater. 15/2005)
Authors: Kotlyar A. B. , Borovok N. , Molotsky T. , Cohen H. , Shapir E. , Porath D.
Published: July 2005

The cover picture is an artistic view, designed by Noam Hamou, of a G‐wire, probably a G4‐DNA nanowire, where the schematic spiral and tetrad are emerging from a single molecule deposited on a mica surface, as imaged by AFM. Kotlyar and co‐workers report on p. 1901 on the development of novel long monomolecular G‐wires that, upon self‐folding, form structures of consecutive guanine tetrads with and without metal ions in the inner channel of the molecule. The continuity of the molecule backbone and its improved stiffness suggest that this single DNA‐based structure might be useful for nanoelectronic applications.
Engineering perfumes
Authors: Mata Vera G. , Gomes Paula B. , Rodrigues Alírio E.
Published: July 2005

A new concept of perfumery ternary diagrams (PTDs), based on an analogy between perfume pyramid structure and engineering ternary diagrams, is described. These diagrams allow a fast theoretical evaluation of the odor value in the headspace for all possible concentrations of a perfume liquid mixture constituted by three fragrant components and one solvent base, thus eliminating a long trial‐and‐error experimental work to analyze the headspace composition. The effect of the nonidealities in the liquid phase arising from molecular interactions was analyzed, as well as the effect of ethanol in a test mixture composed of limonene, geraniol, and vanillin. A diffusion model was used to simulate the evaporation of a small and finite sample of perfume test mixture. The changes in the liquid phase and in the gas–liquid interface were followed using the PTDs developed in this work. A characteristic point of a PTD was used as the initial mixture for simulating the evaporation of the small amount of perfume as a function of time and space. The performance parameters, such as impact, tenacity, diffusion, and volume, were discussed based on these results. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Novel process for diethylacetal synthesis
Authors: Silva Viviana M. T. M. , Rodrigues Alírio E.
Published: July 2005

This work presents the development of a novel process for the production of diethylacetal from the reaction between ethanol and acetaldehyde catalyzed by the acid resin Amberlyst® 15 using simulated moving‐bed reactor (SMBR) technology. The methodology used combines modeling/simulation with laboratory‐ and pilot‐scale experiments. The kinetic law of the reaction was measured from experiments in a batch catalytic reactor. The adsorption parameters were obtained from experiments performed in a fixed‐bed adsorption column. Laboratory experiments in fixed‐bed adsorptive reactors were performed and used to validate model and simulation tools. The SMBR technology was applied for diethylacetal production and separation with 87% purity and the acetaldehyde conversion was about 98%. The influence of feed composition, switching time, and mass‐transfer resistance on the SMBR performance was analyzed by simulation. The reaction/separation region was determined using separation zone methodology. Simulated results show that high acetal purities can be achieved for 100% acetaldehyde conversion. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Elevation of 12/15 lipoxygenase products in AD and mild cognitive impairment
Authors: Yao Yuemang , Clark Christopher M. , Trojanowski John Q. , Lee Virginia M.‐Y. , Praticò Domenico
Published: July 2005

The 12/15 lipoxygenase (12/15LOX) enzyme is increased in pathologically affected frontal and temporal regions of Alzheimer's disease (AD) brains compared with controls. Herein, we measured 12(S)‐HETE and 15(S)‐HETE levels, products of 12/15LOX, in cerebrospinal fluid (CSF) of normal individuals, subjects with mild cognitive impairment (MCI) and AD. Compared with controls, there was a significant increase of both metabolites in CSF from AD and MCI, which correlated with lipid peroxidation and tau protein levels. These results suggest that the activation of this enzyme occurs early in the course of AD, before the onset of overt dementia, thereby implicating 12/15LOX‐mediated lipid peroxidation in the pathogenesis of AD. Ann Neurol 2005
Mutations in phenotypically mild D‐2‐hydroxyglutaric aciduria
Authors: Struys Eduard A. , Korman Stanley H. , Salomons Gajja S. , Darmin Patricia S. , Achouri Younes , Van Schaftingen Emile , Verhoeven Nanda M. , Jakobs Cornelis
Published: July 2005

D‐2‐hydroxyglutaric aciduria is a neurometabolic disorder with mild and severe phenotypes. Recently, we reported pathogenic mutations in the D‐2‐hydroxyglutarate dehydrogenase gene as the cause of the severe phenotype of D‐2‐hydroxyglutaric aciduria in two patients. Here, we report two novel pathogenic mutations in this gene in one patient with a mild presentation and two asymptomatic siblings with D‐2‐hydroxyglutaric aciduria from two unrelated consanguineous Palestinian families: a splice error (IVS4‐2A→G) and a missense mutation (c.1315A→G;p.Asn439Asp). Overexpression of this mutant protein showed marked reduction of the enzyme activity. Ann Neurol 2005
Surgical outcome and prognostic factors of cryptogenic neocortical epilepsy
Authors: Lee Sang Kun , Lee Seo Young , Kim Kwang‐Ki , Hong Kkeun‐Sik , Lee Dong‐Soo , Chung Chun‐Kee
Published: July 2005

Surgical treatment of cryptogenic neocortical epilepsy is challenging. The aim of this study was to evaluate surgical outcomes and to identify possible prognostic factors including the results of various diagnostic tools. Eighty‐nine patients with neocortical epilepsy with normal magnetic resonance imaging (35 patients with frontal lobe epilepsy, 31 with neocortical temporal lobe epilepsy, 11 with occipital lobe epilepsy, 11 with parietal lobe epilepsy, and 1 with multifocal epilepsy) underwent invasive study and focal surgical resection. Patients were observed for at least 2 years after surgery. The localizing values of interictal electroencephalogram (EEG), ictal scalp EEG, interictal 18F‐fluorodeoxyglucose positron emission tomography (FDG‐PET), and subtraction ictal single‐photon emission computed tomography were evaluated. Seventy‐one patients (80.0%) had a good surgical outcome (Engel class 1–3); 42 patients were seizure free. Diagnostic sensitivities of interictal EEG, ictal scalp EEG, FDG‐PET, and subtraction ictal single‐photon emission computed tomography were 37.1%, 70.8%, 44.3%, and 41.1%, respectively. Localization by FDG‐PET and interictal EEG was correlated with a seizure‐free outcome. The localizing value of FDG‐PET was greatest in neocortical temporal lobe epilepsy. The focalization of ictal onset and also ictal onset frequency in invasive studies were not related to surgical outcome. Concordance with two or more presurgical evaluations was significantly related to a seizure‐free outcome. Ann Neurol 2005
Transcranial ultrasound shows nigral hypoechogenicity in restless legs syndrome
Authors: Schmidauer Christoph , Sojer Martin , Seppi Klaus , Stockner Heike , Högl Birgit , Biedermann Birgit , Brandauer Elisabeth , Peralta Cecilia M. , Wenning Gregor K. , Poewe Werner
Published: July 2005

In patients with Parkinson's disease, hyperechogenicity of the substantia nigra using transcranial ultrasound has been related to increased tissue concentrations of iron. Recently, deficient iron transport mechanisms in substantia nigra neurons have been described in postmortem tissue of patients with restless legs syndrome (RLS). This study was performed to study substantia nigra echogenicity in RLS patients compared with normal control subjects and Parkinson's disease patients. RLS patients had significantly reduced midbrain areas of hyperechogenicity compared with control subjects, and even more markedly reduced hyperechogenicity compared with Parkinson's disease patients. These findings lend further support to nigral iron deficiency as a pathogenetic factor in RLS. Ann Neurol 2005
On increasing the efficiency of amine antioxidant
Authors: Lin D. G. , Vorobieva E. V.
Published: July 2005

The amine antioxidant, Neozon D, was treated to increase its effectiveness in suppressing oxidation of polyethylene in contact with copper. It was found that this antioxidant becomes more efficient after interaction with a copper substrate. These experimental results show that the role of substrate is to catalyze oxidation transformations in the antioxidant. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 401–406, 2005
Effects of filler treatments on the mechanical, flow, thermal, and morphological properties of talc and calcium carbonate filled polypropylene hybrid composites
Authors: Leong Y. W. , Bakar M. B. Abu , Mohd. Ishak Z. A. , Ariffin A.
Published: July 2005

Commercially available neoalkoxy titanate (Lica 12) and organosilane (3‐aminopropyltriethoxysilane) coupling agents were used to treat talc and calcium carbonate (CaCO3) to compare their effects with those of untreated fillers upon their incorporation into polypropylene (PP). Commercial stearic acid treated CaCO3 was also used to widen the scope of the study. Single‐filler PP composites (containing either talc or CaCO3) and hybrid‐filler composites (containing a mixture of talc and CaCO3) were compounded on a twin‐screw extruder and subsequently injection‐molded into dumbbells. The silane and titanate treatments dramatically increased the elongation at break for both the single‐filler and hybrid‐filler composites, whereas stearic acid did not. There was also a moderate improvement in the impact strength of the composites, particularly those treated with Lica 12. The hybrid composites, through the synergistic coalescence of positive characteristics from talc and CaCO3, had exceptionally good impact properties, more so with the aid of the coupling agents. For example, the impact strength value of a Lica 12 treated hybrid composite was the greatest for all the composites studied, overshadowing the superiority of the CaCO3‐filled PP composites, which predominantly had the highest impact properties. Further investigations of the thermal and morphological properties were also conducted to facilitate the determination of the coupling mechanisms and their interesting effects on the hybrid composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 413–426, 2005
Preparation and mechanical properties of polypropylene/clay nanocomposites for automotive parts application
Authors: Hong Chae Hwan , Lee Young Bum , Bae Jin Woo , Jho Jae Young , Nam Byeong Uk , Hwang Tae Won
Published: July 2005

Nanocomposites of polypropylene with organically modified clays were compounded in a twin‐screw extruder by a two‐step melt compounding of three components, i.e., polypropylene, maleic anhydride grafted polypropylene (PPgMA), and organically modified clay. The effect of PPgMA compatibilizers, including PH‐200, Epolene‐43, Polybond‐3002, and Polybond‐3200, with a wide range of maleic anhydride (MA) content and molecular weight was examined. Nanocomposites' morphologies and mechanical properties such as stiffness, strength, and impact resistance were investigated. X‐ray diffraction patterns showed that the dispersion morphology of clay particles seemed to be determined in the first compounding step and the further exfoliation of clays didn't occur in the second compounding step. As the ratio of PPgMA to clay increased, the clay particles were dispersed more uniformly in the matrix resin. As the dispersibility of clays was enhanced, the reinforcement effect of the clays increased; however, impact resistance decreased. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 427–433, 2005
Synthesis and characterization of photoluminescent copolymer containing 1,1′‐binaphthyl and fluorene rings
Authors: Feng Liheng , Bie Hongyan , Chen Zhaobin
Published: July 2005

The luminescent polymer, F‐DMBN, containing 2,2′‐dimethacrylanido‐1,1′‐binaphthyl (DMBN) and 9,9‐diphenylfluorene, is synthesized by the Heck reaction of halogenated and olefinic monomers. The structures are characterized by MS, 1H‐NMR, and IR, and the photoluminescent properties are investigated by UV/vis absorption and fluorescence spectra. The results show that the polymer emits blue and blue–violet light. The luminescence quantum yield is 0.424 in ethanol and the emission spectra exhibit obvious solvent effects. In addition, the light emitting can be quenched by both electron donor (N,N‐dimethylaniline) and electron acceptor (fullerene), where the processes follow the Stern–Volmer equation. Moreover, the interaction between F‐DMBN and carbon nanotubes is also studied by fluorescent quenching. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 434–438, 2005
Effect of volume fraction and particle size on wall slip in flow of polymeric suspensions
Authors: Gulmus Sergul Acikalin , Yilmazer Ulku
Published: July 2005

For especially highly concentrated suspensions, slip at the wall is the controlling phenomenon of their rheological behavior. Upon correction for slip at the wall, concentrated suspensions were observed to have non‐Newtonian behavior. In this study, to determine the true rheological behavior of model concentrated suspensions, “multiple gap separation method” was applied using a parallel‐disk rheometer. The model suspensions studied were polymethyl methacrylate particles having average particle sizes, in the range of 37–231 μm, in hydroxyl terminated polybutadiene. The effects of particle size and solid particle volume fraction on the wall slip and the true viscosity of model concentrated suspensions were investigated. It is observed that, as the volume fraction of particles increased, the wall slip velocity and the viscosity corrected for slip effects also increased. In addition, for model suspensions in which the solid volume fraction was ≥81% of the maximum packing fraction, non‐Newtonian behavior was observed upon wall slip correction. On the other hand, as the particle size increased, the wall slip velocity was observed to increase and the true viscosity was observed to decrease. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 439–448, 2005
Interfacial factors affecting polymeric diphenylmethane diisocyanate/wood bond strength
Authors: Sonnenschein Mark F. , Wendt Benjamin L. , Sonnenschein G. Franklin
Published: July 2005

Polymeric diphenylmethane diisocyanate (pMDI) has been used for making wood board composites for over 30 years, although its growth in application has been limited mainly by the perception that it is a high‐cost alternative to formaldehyde‐based adhesives. Increased use of pMDI adhesive in making wood composites will require optimization of the process variables involved. One such factor is the unresolved question of the interfacial aspects most responsible for building strong wood composites. Some argue that adhesive surface coverage is primarily responsible for board strength; others assert that penetration of the pMDI into the wood matrix is a primary characteristic of strong boards. This article will provide evidence that the interfacial aspect most important in building board strength is surface coverage of the wood particles or fibers. Experiments controlling the depth of pMDI penetration into wood matrices and then measuring their adherend strength were performed. We also calculated the potential efficiencies to be obtained from maximizing the surface coverage and minimizing the matrix penetration using a spherical sector model. Neither high nor low pMDI viscosity offered a significant advantage in surface covering pine or oak, although it is speculated that minimizing the droplet size of pMDI in the resination step could lead to substantial efficiency improvements in adhesive coverage. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 449–455, 2005
Rheological and processing properties of purified natural rubber
Authors: Rattanasom N. , Suchiva K.
Published: July 2005

Studies were performed on the nature and magnitude of the variabilities in the rheological and processing properties of purified natural rubber (PNR). PNR samples were prepared from three clones of NR (RRIM 600, GT 1, and KRS 156). The corresponding whole NR (WNR) containing total nonrubber substances was also prepared for comparative purposes. All samples were stored for 3 months to elucidate the effect of storage on their rheological and processing properties. A novel study was also conducted to determine whether the commonly reported variabilities in the rheological properties had actual effects on the mixing. These were studied by means of an instrumented torque rheometer fitted with a small mixer head. The results showed that the vulcanization time of PNR was consistent and did not show clonal variation. PNR exhibited large clonal variation in the viscosity at a low shear rate and storage hardening, similar to the ordinary NR. However, the variations in the viscosity of PNR became less evident as the shear rates increased toward 200 s−1. The significant findings were that the observed variations in the rheological properties had no practical effect on the mixing time of PNR samples with carbon black. Moreover, the PNR samples required less energy for mixing than their WNR counterparts. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 456–465, 2005
Biodegradation behavior of acid‐containing cellulose acetate film in soil
Authors: Yamashita Yoichiro , Endo Takeshi
Published: July 2005

The biodegradation behavior of various cellulose acetate (CA; degree of substitution = 2.5) films that contain acids was examined by a laboratory soil burial test to clarify the effects of additives on the biodegradability of CA. The biodegradation rate of the CA films containing polyphosphoric acid, phosphoric acid, and p‐toluenesulfonic acid increased compared to that of the nonadditive CA film. CA films containing mandelic acid and maleic acid showed a small tendency to increase. Conversely, CA films containing adipic acid did not affect the biodegradability of CA. A similar experiment was carried out with a sterilization system. The acid‐containing CA film, which showed an accelerated biodegradation rate, was chemically deacetylated by contact with water in the environment and was consequently converted to a lower degree of acetyl group substitution matter that had higher biodegradability. An IR analysis suggested that this deacetylating ability of acids is correlated with the intensity of their interaction with the acetyl group of CA. In the biodegradation process, the contact efficiency of acids to CA was considerably lowered by the elution of internal acids with time. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 466–473, 2005
Investigation on dry spinning process of ultrahigh molecular weight polyethylene/decalin solution
Authors: Sun Yushan , Wang Qingrui , Li Xiaojun , Chen Xueying , Ma Yan , Zhang Qi , Jin Xiaofang , Jiang Yuan , Sun Lin , Luo Qiang
Published: July 2005

The relationship between the draw‐down ratio in the dry spinning process of ultrahigh molecular weight polyethylene/decalin solution and the fiber performance through maximized after‐drawing was investigated. The structural development during the after‐drawing process was analyzed by scanning electron microscopy, differential scanning calorimetry, wide‐angle X‐ray diffraction, sonic velocity, and FTIR measurements. An optimum draw‐down ratio was found in the multihole dry spinning process, which may be explained by molecular disentanglement and the composite effect of entropy and the viscosity component. The as‐spun fiber by draw‐down had an obvious shish kebab morphology, lower crystallinity, and a higher melting temperature compared with a free extrusion sample, and higher crystallinity and melting temperature compared with the fiber by first‐stage after‐drawing. During the subsequent after‐drawing process, the crystallinity, melting temperature, X‐ray diffraction, and sonic velocity orientation factors increased slowly in the higher after‐drawing ratio region, which was not consistent with the rising tendency of the tensile properties. The polarized and unpolarized IR spectra reflected the variations of the orientation and the content of the folded chains. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 474–483, 2005
Effects of heat treatment on the properties of heterogeneous cation permeable membranes from blends of poly(ether sulfone)/sulfonated poly(phenylene sulfide) and phenolphthalein poly(ether ether ketone)/sulfonated poly(phenylene sulfide)
Authors: Yan Hu Ke , Wen Xu Tong , Hua Yang Wei , Xun Fu Yan
Published: July 2005

The effects of heat treatment on the properties of membranes prepared from blends of poly(ether sulfone)/sulfonated poly(phenylene sulfide) (SPPS) and phenolphthalein poly(ether ether ketone)/SPPS were studied in detail. The membranes' fundamental properties, including water content, transport number, diffusion coefficient of electrolytes, flux, and so on, changed with both treated temperature and time, whereas the ion‐exchange capacity and electrical resistance remained approximately unchanged. The trends may have been due to the possible structural change resulted from the shrinking of the polymers forming the membranes. Furthermore, the membranes also retained a good physical appearance at temperatures below 220°C. Therefore, a series of heterogeneous membranes with desired conductivities and selectivities as well as proper water contents, which could satisfy different industrial purposes, such as electrodialysis, diffusional dialysis, and proton exchange, were achieved by simple heat treatment for a proper time and at a proper temperature. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 494–499, 2005
Study on morphology development for in situ fiber–reinforced composites by blending polyolefin and polycaprolactone
Authors: Semba Takeshi , Kitagawa Kazuo , Nakagawa Masahiko , Semo Ishiaku Umaru , Hamada Hiroyuki
Published: July 2005

The morphology developments and interfacial properties of extruded polyethylene/polycaprolactone and polypropylene/polycaprolactone blends were investigated. The interfacial thicknesses of both polymer blends were thin and this was investigated by interfacial tension measurement in the melt state. The aspect of boundary area was observed by AFM, and a clear line could be observed at the interface area as a result of thin interfacial thickness. The in situ fiber formation of the dispersed phase was remarkably generated under elongational flow (between die exit and solidification) rather than under shear flow (in the cylinder and die). Drawing ratio was varied at three levels to study its effect on elongation of the dispersed phases. The dispersions dramatically changed from spherical to spheroidal and filament shapes depending on the drawing ratio. Reduced capillary number (Ca*) was used to characterize droplet deformation. The deformation mode under shear flow was classified as nondeformation mode due to the fact that the Ca* was almost 0. On the other hand, the deformation mode under elongational flow was classified into filament shape mode (Ca* > 4). This classification was in agreement with the SEM images. The tensile properties were increased at the border line where the Ca* was 4.0. The melt interfacial tensions of polyolefin/polycaprolactone were relatively large, and a clear line could be observed at the interface area as a result of little affinity of polymer interface. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 500–508, 2005
Preparation and characterization of layered membranes constructed by sequential redox‐initiated grafting onto polyacrylonitrile ultrafiltration membranes
Authors: Belfer S. , Bottino A. , Capannelli G.
Published: July 2005

Layered membranes were prepared by sequential grafting—by means of redox initiators—of water‐soluble monomers, with oppositely charged ionic groups, onto ultrafiltration (UF) polyacrylonitrile (PAN) membranes at room temperature. Grafting of a single layer of 2‐hydroxyethylmethacrylate (HEMA) onto a PAN membrane gave a highly grafted membrane with a relatively high water flux. Bilayered membranes with various properties containing poly‐2‐(dimethylamino)ethyl methacrylate (p‐2DMAEMA) as the bottom layer and polymethacrylic acid or polystyrenesulfonic acid (p‐SSA) as the upper layer were prepared and compared—by means of infrared spectroscopy and electron microscopy—with single‐layered membranes of grafted polyhydroxyethylmethacrylate. Layered membranes exhibited a significant decline in water flux in comparison with the initial UF membranes. The flux could, however, be manipulated by controlling the concentration of monomers, the time of grafting, and the number of layers. When four layers of p‐2DMAEMA and p‐SSA were sequentially grafted onto a PAN membrane, pure water fluxes were stable over a wide range of pH values and did not change over long storage times. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 509–520, 2005
Enzyme electrodes for determination of total phenolic capacity of red wines
Authors: Kıralp S. , Cirpan A. , Toppare L.
Published: July 2005

A tyrosinase‐modified electrode, based on physical entrapment of enzyme in copolymer matrix of decanedioic acid bis(4‐pyrrol‐1‐yl‐phenyl) ester (DAPE) with pyrrole was constructed and used to investigate the total amount of phenolics in red wines. Kinetic parameters, Vmax, and Km, were determined. Also, temperature, pH optimizations, operational stability and shelf life of the enzyme electrode were examined. Surface morphologies of the films were studied by scanning electron microscope. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 521–524, 2005
Resins containing amino and carboxylic acid groups. Synthesis, characterization, and metal ion retention properties
Authors: Rivas Bernabé L. , Villegas Sandra
Published: July 2005

The crosslinked poly[3‐(methacryloylamino)propyl]dimethyl(3‐sulfopropyl)ammonium hydroxide], P(MAPDSA), and poly[3‐(methacryloylamino)propyl]dimethyl(3‐sulfopropyl)ammonium hydroxide‐co‐acrylic acid], P(MAPDSA‐co‐AA), were synthesized by radical polymerization. The resins were completely insoluble in water. Due to the lower metal ion retention of P(MAPDSA), the metal ions investigated under competitive and noncompetitive conditions for Cu(II), Cd(II), Hg(II), Zn(II), Pb(II), and Cr(III) ions by batch and column equilibrium procedures were carried out only for P(MAPDA‐co‐AA), particularly for Hg(II). The resin–Hg(II) ion equilibrium was achieved before 15 min. The resin showed a maximum retention capacity value for Hg(II) at pH 2 of 1.89 meq/g. The resin showed a high selectivity to Hg(II) ions. The recovery of the resin was investigated at 25°C with different concentrations of HNO3 and HClO4. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 525–530, 2005
Lightning‐induced magnetic anomalies on archaeological sites
Authors: Jones Geoffrey , Maki David L.
Published: July 2005

Recent studies of known lightning impacts and laboratory testing of samples from a suspected lightning‐induced anomaly appearing in magnetic survey data allow us to characterize these formerly enigmatic responses. Remanent magnetization associated with the current path of a lightning discharge produces strong anomalies that can be recognized in magnetic survey data, and can be identified positively using laboratory methods. Copyright © 2005 John Wiley & Sons, Ltd.
Recurrence after segmental resection for colonic Crohn's disease
Authors: Polle S W , Slors J F M , Weverling G J , Gouma D J , Hommes D W , Bemelman W A
Published: July 2005

Background

Segmental colonic resection is commonly performed in patients with colorectal Crohn's disease. The aim of this study was to evaluate the outcome after segmental colonic resection and to define risk factors for re-resection.

Methods

Consecutive patients who had an initial segmental colonic resection for Crohn's colitis between 1987 and 2000 were evaluated. Patients who underwent ileocolonic resection were excluded. Patient-, disease- and treatment-related variables were assessed as possible risk factors for disease recurrence.

Results

Ninety-one patients (62 women) with a median follow-up of 8·3 years were studied. Thirty patients (33 per cent) had at least one re-resection, of whom 20 finally underwent total (procto)colectomy. Female sex and a history of perianal disease were identified as independent risk factors for re-resection: odds ratio 12·52 (95 per cent confidence interval (c.i.) 2·38 to 65·84) and 13·94 (95 per cent c.i. 3·02 to 64·27) respectively. Forty (44 per cent) of the 91 patients had a stoma at the end of the study period. Of the 30 patients who had re-resection, 24 finally had a stoma.

Conclusion

Segmental resection for Crohn's colitis is justified. Recurrence is more frequent in women and in those with a history of perianal disease.
Treatment strategy for patients with colorectal cancer and synchronous irresectable liver metastases
Authors: Benoist S , Pautrat K , Mitry E , Rougier P , Penna C , Nordlinger B
Published: July 2005

Background

The aim of this case-matched study was to determine the best treatment strategy for patients with asymptomatic colorectal cancer and irresectable synchronous liver metastases.

Methods

Between 1997 and 2002, 27 patients with asymptomatic colorectal cancer and irresectable synchronous liver metastases were treated by chemotherapy without initial primary resection (chemotherapy group). These 27 patients were compared with 32 patients matched for age, sex, performance status, primary tumour location, number of liver metastases, nature of irresectable disease and type of chemotherapy, but who were treated initially by resection of primary tumour (resection group).

Results

The 2-year actuarial survival rate was 41 per cent in the chemotherapy group and 44 per cent in the resection group (P = 0·753). In the latter group, the mortality and morbidity rates for primary resection were 0 and 19 per cent (six of 32 patients) respectively. In the chemotherapy group, intestinal obstruction related to the primary tumour occurred in four of 27 patients. The mean overall hospital stay was 11 days in the chemotherapy group and 22 days in the resection group (P = 0·003).

Conclusion

Systemic chemotherapy without resection of the bowel cancer is the option of choice because, for most patients, it is associated with a shorter hospital stay and avoids surgery without a detrimental effect on survival.
Column selection and method development for the separation of nucleoside phosphotriester diastereoisomers, new potential anti‐viral drugs. Application to cellular extract analysis
Authors: Goossens J. F. , Foulon C. , Villard A.‐L. , Puy J.‐Y. , Lefebvre I. , Perigaud C. , Vaccher C. , Bonte J. P.
Published: July 2005

Analytical HPLC methods using derivatized cellulose and amylose chiral stationary phases used in normal and reversed‐phase modes were developed for the diastereoisomeric separation of mononucleotide prodrugs (pronucleotides) of 3′‐azido‐2′,3′‐dideoxythymidine (AZT). The resolutions were performed with two silica‐based celluloses using normal and reversed‐phase methodologies: Tris‐3,5‐dimethylphenylcarbamate (Chiralcel OD‐H and Chiracel OD‐RH) and Tris‐methylbenzoate (Chiralcel OJ and OJ‐R). Two amyloses phases, Tris‐3,5‐dimethylphenylcarbamate (Chiralpak AD) and Tris‐(S)‐1‐phenylethylcarbamate (Chiralpak AS), were used in normal‐phase mode. Additionally, we developed separation using two stationary phases with immobilized cyclodextrins in reversed‐phase and polar‐organic modes. The mobile phase and the chiral stationary phase were varied to achieve the best resolution. Different types and concentration of aliphatic alcohols, acetonitrile or water in the mobile phase were also tested for the different separation modes. An optimal baseline separation (Rs > 1.5) was readily obtained with all silica‐based celluloses and amyloses using a normal‐phase methodology. The different columns gave complementary results in term of resolution. Limits of detection and quantification were 0.12–0.20 and 0.40–0.67 µm, respectively. This analytical method was applied in a preliminary study for the pronucleotide 2 quantification in cellular extract. Copyright © 2005 John Wiley & Sons, Ltd.
The factors that influence the elution order for the resolution of amino acids on vancomycin phase using the polar‐organic mobile phases after their pre‐column derivatization with electrophilic reagents
Authors: Chen S.
Published: July 2005

A variety of amino acids were enantioresolved on a vancomycin bonded chiral phase using the polar‐organic mobile phases after their pre‐column derivatization with electrophilic reagents in alkaline medium. The resolution was highly dependent on the analyte's structure and was enhanced as the aromatic side‐chain group on the skeleton of analyte for π–π interaction with the chiral selector became available. The steric hindrance resulting from the bulky side‐chain group on the analyte also affected the resolution. Elution reversal, not found on the teicoplanin phase under the same chromatographic conditions, was possible through altering the type of reagent used in the derivatizing reaction (e.g. 2,4‐difluorophenylisothiocyanate to 2,4‐difluorophenylisocyanate). It is believed that the steric hindrance, as a result of the bulky sulfur atom in reagents such as methylisothiocyanate and others examined in this study, was responsible for the reversed elution order. The bulkiness of the substituent on the aromatic ring of derivatizing reagents (i.e. 2,3‐ and 3,5‐dichlorophenylisothiocyanate) was observed to affect the resolution and alter the elution order as well. Copyright © 2005 John Wiley & Sons, Ltd.
Enantiorecognition on solid chiral selectors using microbatch technology: an example of limitation in case of strong association in the racemate
Authors: Roussel Christian , Rafii Esfandiar , Rio Alberto Del , Vanthuyne Nicolas
Published: July 2005

When they were independently tested, the enantiomers of N,N′‐bis(salicylidene)‐trans‐1,2‐cyclohexanediamine showed a large difference in adsorption on new chiral selectors using microbatch technology. Surprisingly, when these enantiomers were applied on the same supports as a racemic mixture, no discrimination was observed even though suitable adsorption existed. When a mixture enriched in one enantiomer (scalemic mixture) was applied, the resulting supernatant contained the racemic form and the enantiomer in excess was adsorbed on the support together with a part of racemate. This behavior, which militates in favor of a strong heterochiral dimer formation in the racemate, was revealed using microbatch technology but remained hidden on classical column chromatography on chiral support. Molecular dynamics calculations corroborate this hypothesis, showing a favorite binding mode of the heterochiral dimer, which is stabilized by various inter‐ and intramolecular interactions. Our findings may be considered as a new limitation of microbatch technology, but they may have some inference in case of chiral amplification using the N,N′‐bis(salicylidene)‐trans‐1,2‐cyclohexanediamine enantiomers as chiral ligands. Copyright © 2005 John Wiley & Sons, Ltd.
Synthesis and evaluation of a new biselector s‐triazine based chiral stationary phase for enantioselective HPLC: potentiality of the approach and perspectives
Authors: Lecci Cristina , Iuliano Anna
Published: July 2005

A s‐triazine scaffold bearing a free and a protected amino group was used for connecting two different chiral auxiliaries, whose enantiodiscriminating capabilities in enantioselective chromatography are well documented. A biselector system was synthesized and, after linkage to silica gel, used for the chromatographic resolution of different racemic analytes, chosen among the compounds resolved by the two different isolated chiral auxiliaries. The obtained chromatographic results were compared with literature data related to the use of the two chiral stationary phases (CSPs) whose chiral moieties constitute the biselector CSP, allowing us to gain useful information about potentialities and limitations of this approach for obtaining independent CSPs having broader applicability with respect to the classical independent monoselector CSPs. Copyright © 2005 John Wiley & Sons, Ltd.
Application of dimethyl‐β‐cyclodextrin as a chiral selector in capillary electrophoresis for enantiomer separation of ephedrine and related compounds in some drugs
Authors: Liu Li‐Bin , Zheng Zhi‐Xia , Lin Jin‐Ming
Published: July 2005

Dimethyl‐β‐cyclodextrin (DM‐β‐CD) modified capillary electrophoresis has been developed for chiral separation of ephedrine and related compounds, such as (±)‐norephedrine, (±)‐N‐methylephedrine, (±)‐ephedrine and (+)‐pseudoephedrine. The influence of some crucial parameters such as buffer concentration, pH value, DM‐β‐CD concentration, applied voltage and separation temperature on the separation was investigated. Under the optimum conditions, i.e. 40 mm DM‐β‐CD in 75 mm Tris (pH 2.5) as the running electrolyte, separation voltage +25 kV and temperature 25°C, a satisfactory separation of the enantiomers was accomplished. The detection limits (S/N = 3) ranged from 65 to 161 ng/mL and the linear range was 0.15 to 101.0 µg/mL for pressure injection. The present method was successfully applied for the analysis of a series of drugs such as anti‐tussive, the drug for rheum, the drug for rhinitis and a Chinese traditional herbal medicine, Ephedrae herba (Ma‐Huang in Chinese). The recoveries of ephedrine and related compounds in real samples ranged from 97.6 to 103.5%. This method is useful in the simple and rapid analysis of ephedrine derivatives in marketed products. Copyright © 2005 John Wiley & Sons, Ltd.
Gas chromatographic quantification of free D‐amino acids in higher vertebrates
Authors: Pätzold Ralf , Schieber Andreas , Brückner Hans
Published: July 2005

D‐amino acids were determined in brain, body fluids (urine, blood coagulate, serum, plasma) and faeces of animals belonging to nine out of 11 taxonomic orders of vertebrates (Artiodactyla, Aves, Carnivora, Lagomorpha, Marsupalia, Osteichthyes, Primates, Rodentia, Tubilidentata). Free amino acids were isolated by means of cation exchangers and converted into volatile N(O)‐perfluoroacylamino acid propyl esters. Derivatives of amino acids were separated into d‐ and l‐enantiomers using Chirasil‐l‐Val capillary columns and detected by selected ion monitoring mass spectrometry. Quantification of amino acids was achieved by comparison of analytes with amino acid standards using l‐norleucine as internal standard. Large relative amounts of d‐serine were determined in brains of mammals but not of birds. In body fluids the d‐enantiomers of most proteinogenic l‐amino acids were detected, largest absolute and relative amounts were found in urine. Therein quantities of d‐Ala and d‐Ser exceeded 50% relative to the l‐enantiomers in many instances. Feeding animals with diet fortified with dl‐Met resulted in excretion of almost racemic Met in urine. d‐Amino acids were also abundant in faeces of rodents. The data confirm that d‐amino acids are common in body fluids and certain tissues of vertebrates. Copyright © 2005 John Wiley & Sons, Ltd.
Thin‐layer chromatography separation of enantiomers of verapamil using macrocyclic antibiotic as a chiral selector
Authors: Bhushan R. , Gupta Deepak
Published: July 2005

Silica gel thin‐layer chromatography plates impregnated with macrocyclic antibiotic, vancomycin, as chiral selector were prepared and used for the resolution of (±)‐verapamil. A mobile phase system of acetonitrile–methanol–water (15:2.5:2.5, v/v) was worked out systematically. The effects of chiral selector, temperature and pH on resolution were also studied. The spots were detected with iodine vapors and the detection limit was found to be 0.074 µg of each enantiomers. Copyright © 2005 John Wiley & Sons, Ltd.
Photostability studies for micellar liquid chromatographic determination of nifedipine in serum and urine samples
Authors: Gil‐Agustí M. T. , Carda‐Broch S. , Ll. Monferrer‐Pons  , Esteve‐Romero J. S.
Published: July 2005

Nifedipine is a photosensitive compound that is converted into its 4‐(2‐nitrophenyl) pyridine and 4‐(2‐nitrosophenyl) pyridine homologue. In order to obtain the most adequate conditions for handling nifedipine solutions in the analytical laboratory, a number of studies on the decomposition of this compound were performed. A simple micellar liquid chromatographic procedure was described to determine nifedipine in different biological matrices such as serum and urine, and to control its decomposition. To perform the analysis, nifedipine was dissolved in 0.1 m SDS at pH 3 and chromatographed using a mobile phase containing 0.125 m SDS–3% pentanol, pH 3 on a C18 column and UV detection at 235 nm. The chromatographic analysis time was 8 min. The response of the drug for both biological matrices was linear in the 1–100 µg/mL range, with r2 > 0.997 at all times. Repeatability, intermediate precision (CV, %) and limits of quantification and detection (ng/mL) were 0.19, 4.3, 104 and 31 in serum and 0.81, 2.1, 136 and 41 in urine. The method developed here does not show interferences or matrix effects produced by endogenous compounds. Micellar media and mobile phases have the advantage of stabilising the compounds, thus preventing photodegradation and allowing the direct injection of biological samples. Copyright © 2005 John Wiley & Sons, Ltd.
A simple clipping procedure for the dynamic mixed model based on Taylor series approximation
Authors: Kornev N. V. , Tkatchenko I. V. , Hassel E.
Published: July 2005

A simple clipping procedure based on Taylor series approximation was suggested to improve the stability of LES computations using the dynamic mixed model (DMM). The clipping procedure derived from a rigorous mathematical analysis uses terms which are anyway determined in the DMM model and thus, does not require additional calculations. The effect of the clipping was tested by calculations of turbulent mixing in a coaxial jet mixer. The suggested procedure has potential to be extended to LES of complex‐geometry turbulent flows. Copyright © 2005 John Wiley & Sons, Ltd.
Valence Tautomerism: New Challenges for Electroactive Ligands (Eur. J. Inorg. Chem. 15/2005)
Authors: Evangelio Emilia , Ruiz‐Molina Daniel
Published: July 2005

The cover picture shows the potential energy curves for a generic valence tautomeric complex with a schematic representation emphasizing the intramolecular electron transfer between the metal ion and the ligand, which can be induced by different external stimuli such as temperature, pressure or irradiation. The diagram is accompanied by a representation of the different redox‐active ligands involved in valence tautomerism that are presented in the Microreview by E. Evangelio and D. Ruiz‐Molina on p. 2957 ff.
Parametric study on the batch leaching process of Jojoba oil
Authors: Allawzi Mamdouh A. , Abu‐Arabi Mousa K. , Al‐Taher Faraj A.
Published: July 2005

In this study, hexane is used as solvent to extract Jojoba oil in a batch leaching process. The effects of temperature, mixing speed, particle size and solvent‐to‐seed ratio on Jojoba oil extraction were investigated. The best recovery of oil was obtained when the parameters investigated were at the boiling point temperature of the solvent, a particle size of 0.48 mm, a mixing speed of 1000 rpm, and a solvent‐to‐seed ratio of 15 mL/g. The maximum amount extracted was 55 wt‐% under the above‐mentioned operating conditions. The amount extracted at a higher particle size (1.5 mm) was around 44 wt‐%. An empirical model was obtained based on the experimental data, in order to predict the extraction yield under the operating conditions. The derived model is in good agreement with the experimental data, with a maximum deviation of 8%.
Incorporation of γ‐linolenic and linoleic acids into a palm kernel oil/palm olein blend
Authors: Lumor Stephen E. , Akoh Casimir C.
Published: July 2005

Lipozyme RM IM, a 1,3‐regiospecific lipase, was used as a biocatalyst for the incorporation of γ‐linolenic acid (GLA) and linoleic acid (LA) from borage oil into a blend of palm kernel oil and palm olein (50:50, vol/vol). GLA and LA were concentrated as non‐urea‐complex fatty acids (NUCFA) and NUCFA ethyl esters (NUCFAEE) by urea fractionation. Acidolysis and interesterification were conducted in a solvent‐free system with NUCFA and NUCFAEE as acyl donors, respectively. The effects of temperature and substrate mole ratio on incorporation were also studied. Products were analyzed by gas chromatography. NUCFA were a better substrate for GLA incorporation at 45, 55, and 65 °C. The highest incorporation (16.79%) was obtained at 55 °C. NUCFAEE were a better substrate at 75 °C, with 25.06% GLA incorporation compared to 14.09% with NUCFA. Generally, incorporation increased with increasing substrate mole ratio. A structured lipid containing 33% GLA and 9.4% LA was produced with NUCFAEE as acyl donor at 75 °C and a substrate mole ratio of 4.5. Our work showed that the substrate mole ratio was the most important factor affecting incorporation, and the suitability of either substrate as acyl donor was temperature dependent. The enzyme's preference for GLA incorporation over LA was also observed.
Antioxidant properties of extracts and compounds from Psoralea morisiana
Authors: Rosa Antonella , Deiana Monica , Corona Giulia , Atzeri Angela , Incani Alessandra , Appendino Giovanni , Dessì M. Assunta
Published: July 2005

The antioxidant activity of various extracts (MeOH, petroleum ether, EtOAc) from the aerial parts of Psoralea morisiana, an endemic Sardinian plant, was evaluated during autoxidation and iron‐mediated oxidation of linoleic acid at 37 °C and during cholesterol oxidation at 140 °C, in the absence of solvent. The activity of erybraedin C, bitucarpin A and plicatin B, isolated from the extracts, was investigated under the same experimental conditions and compared to that of BHT and α‐tocopherol. All the extracts, erybraedin C (major constituent of the extracts) and plicatin B showed powerful antioxidant properties. None of the extracts and pure compounds showed any prooxidant activity. The cytotoxicity of the extracts, erybraedin C, and plicatin B was further evaluated in VERO cells, a line of fibroblasts derived from monkey kidney. Erybraedin C, at non‐cytotoxic concentrations, showed a strong inhibition of FeCl3‐induced oxidation in VERO cells.
Exciting Supramolecular Architectures: Light‐Induced Processes and Synthetic Transformations in Noncovalent Assemblies
Authors: Huang Chih‐Hao , Bassani Dario M.
Published: July 2005

This review outlines recent advances in the area of supramolecular photochemistry, particularly with respect to the use of noncovalent interactions to direct and control excited‐state processes in the solid phase and in solution. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)