bluuebunny/crossref_metadata_2025 huggingface dataset:
Spider capture silk: performance implications of variation in an exceptional biomaterial
Authors: Swanson Brook O. , Blackledge Todd A. , Hayashi Cheryl Y.
Published: September 2007

Spiders and their silk are an excellent system for connecting the properties of biological materials to organismal ecology. Orb‐weaving spiders spin sticky capture threads that are moderately strong but exceptionally extensible, resulting in fibers that can absorb remarkable amounts of energy. These tough fibers are thought to be adapted for arresting flying insects. Using tensile testing, we ask whether patterns can be discerned in the evolution of silk material properties and the ecological uses of spider capture fibers. Here, we present a large comparative data set that allows examination of capture silk properties across orb‐weaving spider species. We find that material properties vary greatly across species. Notably, extensibility, strength, and toughness all vary approximately sixfold across species. These material differences, along with variation in fiber size, dictate that the mechanical performance of capture threads, the energy and force required to break fibers, varies by more than an order of magnitude across species. Furthermore, some material and mechanical properties are evolutionarily correlated. For example, species that spin small diameter fibers tend to have tougher silk, suggesting compensation to maintain breaking energy. There is also a negative correlation between strength and extensibility across species, indicating a potential evolutionary trade‐off. The different properties of these capture silks should lead to differences in the performance of orb webs during prey capture and help to define feeding niches in spiders. J. Exp. Zool. 307A:654–666, 2007. © 2007 Wiley‐Liss, Inc.
Modulation of brain metabolism by very low concentrations of the commonly used drug delivery vehicle dimethyl sulfoxide (DMSO)
Authors: Nasrallah Fatima A. , Garner Brett , Ball Graham E. , Rae Caroline
Published: September 2007

Dimethyl sulfoxide (DMSO) has long been used in studies as a vehicle to enhance the solubility and transport of ligands in biological systems. The effects of this drug on the outcomes of such studies are still unclear, with concentrations of DMSO reported as “safe” varying considerably. In the present work, we investigated the effects of very low concentrations of DMSO on the brain metabolism of [3‐13C]pyruvate and D‐[1‐13C]glucose using 1H/13C NMR spectroscopy and a guinea pig cortical brain slice model. Our results show that DMSO is accumulated by brain slices. DMSO at all concentrations [0.000025%–0.25% (v/v)] increased the metabolic rate when [3‐13C]pyruvate was used as a substrate and also in the presence of D‐[1‐13C]glucose (0.00025%–0.1% DMSO). These results are consistent with DMSO stimulating respiration, which it may do through altering the kinetics of ATP‐requiring reactions. Our results also emphasize that there is no practical concentration of DMSO that can be used in metabolic experiments without effect. Therefore, care should be taken when evaluating the actions of drugs administered in combination with DMSO. © 2007 Wiley‐Liss, Inc.
The social identity and social networks of ethnic minority groups in organizations: a crucial test of distinctiveness theory
Authors: Leonard Ana Sierra , Mehra Ajay , Katerberg Ralph
Published: September 2007

Distinctiveness theory posits that patterns of social identity and friendship are based on numeric rarity within specific contexts. In ethnically diverse organizations, the theory predicts that members of the smaller ethnic group (relative to members of the larger ethnic group) will: (a) tend to identify and form friendships within their own ethnic group, and (b) lack access to well‐connected individuals in the network of friendship relations. Prior tests have supported these predictions, but they have been unable to rule out the possibility that it was chronic differences in social status and numeric representation in society at large (rather than numeric distinctiveness within specific contexts) that explained the observed patterns of social identity and friendship. In this field‐based study, we examined an organization whose social composition effectively controlled for these confounds. We found that members of the smaller ethnic group tended to identify and form friendships within group, as predicted by distinctiveness theory. However, in contrast to previous work, we found that members of the smaller ethnic group were equally well connected to the center of the friendship network as were the members of the larger ethnic group. Copyright © 2007 John Wiley & Sons, Ltd.
Is cultured tendon fibroblast a good model to study tendon healing?
Authors: Fu Sai‐Chuen , Cheuk Yau‐Chuk , Chan Kai‐Ming , Hung Leung‐Kim , Wong Margaret Wan‐Nar
Published: September 2007

Cultured tendon fibroblasts (CTFs) from intact explants are widely used to study tendon healing in vitro. The significance of these findings may rely on similarities between CTFs and healing tendon fibroblasts in situ. Our purpose was to compare CTFs with fibroblasts cultured from healing tendons. We cultured CTFs from intact and healing tendons at day 7 and day 14 postinjury in a rat model of patellar donor site injury. The mRNA expression of COL1A1, COL3A1, decorin, and biglycan, with or without supplementation of 1 ng/mL TGF‐β1, was compared by quantitative real‐time RT‐PCR. The expression of proliferation cell nuclear antigen (PCNA) and α‐smooth muscle actin (α‐SMA) was determined by immunostain. COL3A1 and decorin mRNA in CTFs was lower as compared to day 7 healing fibroblasts, but its biglycan mRNA level was higher than day 14 healing fibroblasts. TGF‐β1 increased COL1A1 and decorin mRNA in CTFs, but decreased the mRNA of all four genes in day 7 healing tendon fibroblasts. CTFs exhibited lower PCNA immunopositivity as compared to day 7 and day 14 healing fibroblasts, but a higher α‐SMA immunopositivity than cultured day 14 healing fibroblasts. These findings showed that CTFs did not resemble healing tendon cells with respect to major cellular activities related to tendon healing. Thus, fibroblasts from healing tendon may be a more appropriate model for studying cellular activities in tendon healing. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:374–383, 2008
Microstructural adaptation in trapezial bone due to subluxation of the thumb
Authors: Nufer Philipp , Goldhahn Jörg , Kohler Thomas , Kuhn Volker , Müller Ralph , Herren Daniel B.
Published: September 2007

Although the thumb saddle is one of the most common sites of degenerative osteoarthritis in the hand, little is known about the altered microstructure in osteoarthritic trapezial bones. External forces resulting from subluxation of the carpometacarpal joint of the thumb (CMC I) should provoke microstructural changes in the trapezium. The purpose of this study was to compare the regional differences of the microstructure between osteoarthritic and healthy trapezial bones. Fifteen trapezia harvested from female patients with radiologically and clinically diagnosed saddle joint osteoarthritis (OA) were compared with 15 unaffected controls. Microstructural parameters, such as bone volume ratio (BV/TV), three‐dimensional connectivity (Conn.D), trabecular number (Tb.N), and trabecular thickness (Tb.Th) were studied using a microcomputed tomography (microCT) system. While the trapezial height in OA was 22% less, the sclerotic subchondral bone layer thickness was 50% higher in OA compared with the control group (p < 0.001). In the OA group there was a 42% higher bone volume ratio (p ≤ 0.001), an 18% increase in Tb.Th (p = 0.006), and a 10% greater Tb.N (p = 0.034) compared with the control group. Although in both groups BV/TV was significantly lower in the radial region, the radial column showed the highest relative increase in bone volume and structure compared with the control group (+67% BV/TV, +20% Tb.Th, +23% Tb.N). The reinforcement of the bony microstructure in CMC I OA, especially at the radial side, is a sign for bone adaptation reacting to radially shifted joint forces. This has to be considered during the development of new prosthetic alternatives. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:208–216, 2008
Binary chromatographic fingerprinting for quality evaluation of Radix Ophiopogonis by high‐performance liquid chromatography coupled with ultraviolet and evaporative light‐scattering detectors
Authors: Liu Li , Lu Yun , Shao Qing , Cheng Yi‐Yu , Qu Hai‐Bin
Published: September 2007

Radix Ophiopogonis is a widely used traditional Chinese medicine. The quality of Radix Ophiopogonis available in the market varies, and some confusing or fake herbs exist. In order to improve the quality control of Radix Ophiopogonis, a novel fingerprinting method was established using HPLC coupled with UV and evaporative light‐scattering detectors (ELSDs). Extraction with methanol and liquid–liquid extraction with water‐saturated n‐butanol were employed for the preparation of the sample solution. Chromatographic separation was performed on a Lichrospher C18 column (250×4.6 mm id, 5.0 μm particle size) with a linear gradient elution program. UV detection at 280 nm and evaporative light‐scattering detection were utilized to obtain two subfingerprinting chromatograms. A novel protocol for data processing was proposed, in order to identify and remove redundant data obtained by the two detectors, and balance the weight of the two subfingerprints on the similarity values. The method was validated and applied to quality evaluation of 16 samples of Radix Ophiopogonis and related herbs.
Kinetics of the reactions of C2H5, n‐C3H7, and n‐C4H9 radicals with Cl2 at the temperature range 190–360 K
Authors: Eskola Arkke J. , Lozovsky Vladimir A. , Timonen Raimo S.
Published: September 2007

The kinetics of the C2H5 + Cl2, n‐C3H7 + Cl2, and n‐C4H9 + Cl2 reactions has been studied at temperatures between 190 and 360 K using laser photolysis/photoionization mass spectrometry. Decays of radical concentrations have been monitored in time‐resolved measurements to obtain reaction rate coefficients under pseudo‐first‐order conditions. The bimolecular rate coefficients of all three reactions are independent of the helium bath gas pressure within the experimental range (0.5–5 Torr) and are found to depend on the temperature as follows (ranges are given in parenthesis): k(C2H5 + Cl2) = (1.45 ± 0.04) × 10−11 (T/300 K)−1.73 ± 0.09 cm3 molecule−1 s−1 (190–359 K), k(n‐C3H7 + Cl2) = (1.88 ± 0.06) × 10−11 (T/300 K)−1.57 ± 0.14 cm3 molecule−1 s−1 (204–363 K), and k(n‐C4H9 + Cl2) = (2.21 ± 0.07) × 10−11 (T/300 K)−2.38 ± 0.14 cm3 molecule−1 s−1 (202–359 K), with the uncertainties given as one‐standard deviations. Estimated overall uncertainties in the measured bimolecular reaction rate coefficients are ±20%. Current results are generally in good agreement with previous experiments. However, one former measurement for the bimolecular rate coefficient of C2H5 + Cl2 reaction, derived at 298 K using the very low pressure reactor method, is significantly lower than obtained in this work and in previous determinations. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 614–619, 2007
Ab initio calculations of carbon‐containing species and comparison with group additivity results: Part I. C5 species
Authors: Burcat Alexander
Published: September 2007

Twenty‐six C5 compounds and radicals related to combustion processes have been calculated using the ab initio G3//B3LYP method using the atomization enthalpy analysis. The results have been compared to group additivity estimates and literature values where available. Three different group additivity programs were used, and results concerning the comparison are given. The NIST 94 program is more reliable than the other two. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 620–628, 2007
Selective ablation of dental enamel and dentin using femtosecond laser pulses
Authors: Lizarelli R F Z , Costa M M , Carvalho-Filho E , Nunes F D , Bagnato V S
Published: September 2007

The study of the interaction of intense laser light with matter, as well as transient response of atoms and molecules is very appropriated because of the laser energy concentration in a femtosecond optical pulses. The fundamental problem to be solved is to find tools and techniques which allow us to observe and manipulate on a femtosecond time scale the photonics events on and into the matter. Six third human extracted molars were exposed to a femtosecond Ti:Sapphire Q-switched and mode locked laser (Libra-S, Coherent, Palo Alto, CA, USA), emitting pulses with 70 fs width, radiation wavelength of 801 nm, at a constant pulse repetition rate of 1 KHz. The laser was operated at different power levels (70 to 400 mW) with constant exposition time of 10 seconds, at focused and defocused mode. Enamel and dentin surfaces were evaluated concerned ablation rate and morphological aspects under scanning electron microscopic. The results in this present experiment suggest that at the focused mode and under higher average power, enamel tissues present microcavities with higher depth and very precise edges, but, while dentin shows a larger melt-flushing, lower depth and melting and solidification aspect. In conclusion, it is possible to choose hard or soft ablation, under lower and higher average power, respectively, revealing different aspects of dental enamel and dentin, depending on the average power, fluence and distance from the focal point of the ultra-short pulse laser on the tooth surface.
Efficacy of early treatment of facial port wine stains in newborns: A review of 49 cases
Authors: Chapas Anne M. , Eickhorst Kimberly , Geronemus Roy G.
Published: September 2007

Background

Port wine stains (PWS) affect 0.3–0.5% of both sexes of newborns, usually occurring on the face.

Objective

To document safety and effectiveness of cryogen spray cooled, pulsed‐dye laser at higher fluences than previously used to lighten facial PWS in infants ≤6 months, and establish that frequent treatment early in life yields better clearance than if delayed until later in life.

Materials and Methods

Forty‐nine infants who had been treated with pulsed‐dye laser treatments for facial PWS at ≤6 months were identified by case review of photographs, age, sex, PWS severity score prior to laser treatment, number of treatments, and improvement following laser therapy.

Results

Patients averaged 9.3 (range 2–16) treatments at 4–6 week intervals at 7.75–9.5 J/cm2. Average surface area treated was 24.0% with 88.6% average clearance after 1 year. Average clearance was 90.7% for lesions covering <20% surface area and 85.6% for lesions ≥20%. Location (V1, V2, V3, eye, and/or scalp), treated surface area, treatment number, and fluence predicted clearance. Average clearance for sole involvement of V1 was highest (at 93.8%), followed by V2 (at 91.1%), V3 (at 84.3%), V1/V2 (at 83.7%), V1/V2/V3 (at 81.0%), periocular (at 88.6%), and scalp (at 89.9%). All patients tolerated the higher treatment fluences without atrophy or scarring.

Discussion/Conclusions

Frequent, high energy pulsed‐dye laser treatments are safe and highly effective in improving facial PWS in infants ≤6 months of age. Patients with PWS should be referred for pulsed‐dye laser treatment during early infancy. Lesers Surg. Med. 39:563–568, 2007. © 2007 Wiley‐Liss, Inc.
Propagation Rate Coefficient and Fraction of Mid‐Chain Radicals for Acrylic Acid Polymerization in Aqueous Solution
Authors: Buback Michael , Hesse Pascal , Lacík Igor
Published: September 2007

In acrylate polymerizations both SPRs and tertiary MCRs occur. Via pulsed laser polymerization, using a wide range of LPRRs, in conjunction with aqueous‐phase size‐exclusion chromatography, the polymerization of 1.35 mol · L−1 acrylic acid in aqueous solution has been investigated at 6 °C. The sigmoidal decrease in the apparent propagation rate coefficient, k, towards lower LPRRs is in line with recent predictions. At the highest LPRRs, k approaches the rate coefficient of SPR propagation, k, whereas the limiting value of k at low LPRRs approaches the effective propagation rate coefficient, k, which allows for an estimate of the fraction of MCRs under polymerization conditions, xMCR.

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Effective Drug Therapies from Functional, Macromolecular Building Blocks with a Biomimetic Design
Authors: Huang Kui , Croce Teresa A. , Hamilton Sharon K. , Adkins Chinessa T. , Evans Billie L. , Harth Eva
Published: September 2007

Summary: The development of suitable delivery systems for intracellular delivery of proteins, peptides and other bioactive materials opens the possibility to establish refined strategies for small drug delivery, gene delivery and vaccination. We present the assembly of advanced drug delivery systems from tailored building blocks to scaffolds and bioactive cargos to afford targeting and transport across biological barriers. In particular, the utilization of novel molecular transporter will advance the bioavailability of small and macromolecular drugs that show targeted intracellular delivery.
Spectroelectrochemical Reactivities of Novel Polyaniline Nanotube Pesticide Biosensors
Authors: Somerset V. , Klink M. , Akinyeye R. , Michira I. , Sekota M. , Al‐Ahmed A. , Baker P. , Iwuoha E.
Published: September 2007

Summary: The preparation and characterisation of electrosynthetic polyaniline nanomaterials doped with phenanthrene sulphonic acid (PSA) is being presented. The polymeric nanomaterials prepared include processable poly(o‐methoxy aniline) (POMA) and poly(2,5‐dimethoxy aniline) (PDMA). Spectroelectrochemical reactivities of the electroactive polymeric nanotube systems as well as the nanobiosensor systems were studied by SEM, FTIR, UV‐Vis and Subtractively Normalised Fourier Transformed Infrared Spectroscopy (SNIFTIRS) techniques. Furthermore, cyclic and differential pulse voltammetric studies of the nanomaterials were also performed using platinum or thiol‐modulated gold electrodes. The SEM studies confirmed the nanorod morphology of the polyanilines. The heterogeneous rate constant, ko, for the nanopolymeric material and the diffusion coefficient of electrons, De, was calculated and found to be in agreement with values expected for electron hopping along conducting polymer chains. Organophosphate pesticide nanobiosensor devices were prepared by encapsulating acetylcholinesterase (AChE) in the nanopolymeric composite. The biosensor amperometric response to the organophosphate pesticide called diazinon and the carbamate pesticide called carbofuran were studied. The sensor responses to pesticides followed typical electrochemical Michaelis‐Menten kinetics.
Microwave Assisted Graft Copolymerization of N‐Isopropyl Acrylamide and Methyl Acrylate on Cellulose: Solid State NMR Analysis and CaCO3 Crystallization
Authors: Matahwa H. , Ramiah V. , Jarrett W. L. , McLeary J. B. , Sanderson R. D.
Published: September 2007

Summary: Graft copolymerization of N‐isopropyl acrylamide and methyl acrylate on α‐cellulose was carried out under microwave irradiation at specific cut off temperatures with cerium (IV) ammonium nitrate and potassium persulfate (KPS) as the initiating system. The role of KPS was to oxidize Ce (III) to Ce (IV) which is the active species in radical formation. The reactions at a temperature cut off of 60 °C were confirmed by 13C nuclear magnetic resonance cross‐polarization with magic‐ angle spinning (13C NMR CP/MAS) and Fourier‐transform infrared spectroscopy (FTIR). The extent of grafting was calculated from weight gain and 13C resonances. The grafted cellulose was thermally more stable than the parent cellulose. An attempt to do grafting at a higher cut off temperature of 80 °C was made, however, no grafting was observed from 13C NMR CP/MAS but TGA results showed that a cellulose having more thermal stability resulted which was attributed to cross linking. Crystallization of CaCO3 was carried out using the grafted materials as templates showed better nucleation and different crystal structure was observed.
Synthesis of Novel a PEG‐Lysine Polymer
Authors: van Kralingen Leon , Bredenkamp Martin W. , Sanderson Ron D.
Published: September 2007

Summary: A novel PEG functionalized‐L‐lysine‐α‐amino‐N‐carboxy anhydride monomer (L‐Lys(PEG‐(COOBzl))‐NCA) is prepared for the synthesis of carboxylic acid terminated, PEG‐sheathed poly‐lysine biopolymers.
Treatment with antiparkinson and antidepressant drugs: A register‐based, pharmaco‐epidemiological study
Authors: Brandt‐Christensen Mette , Kvist Kajsa , Nilsson Flemming Mørkeberg , Andersen Per Kragh , Kessing Lars Vedel
Published: September 2007

Depressive symptoms and major depression are frequent in patients with Parkinson's disease (PD). However, a systematic knowledge about the treatment with antidepressant drugs among PD patients is missing. We estimated the frequency of antidepressant drug treatment in a national sample of persons treated with antiparkinson drugs (APDs). All persons treated with APDs were identified in the national Danish Prescription database. The subsequent risk of treatment with antidepressants was estimated and compared with the risks for two large control groups. The study period was 5 years. In total, 1,029,737 persons were included. Persons who got APDs had significantly increased rate ratios (RR) of subsequent antidepressant drug treatment compared with an unexposed control group (RR: 2.10 (95% CI: 2.04–2.16)) and with persons who got anti‐diabetic drugs [RR: 1.58 (95% CI: 1.51–1.65)]. Persons treated with APDs have higher frequency of antidepressant drug treatment than have controls. With the reservation that data on drug consumption cannot be directly transferred into conclusions about specific diseases, the present study supports results from other population‐based studies of an association between PD and depression. © 2007 Movement Disorder Society
Neuroimaging follow‐up in a case of Rasmussen's encephalitis with dyskinesias
Authors: de Leva Maria Fulvia , Varrone Andrea , Filla Alessandro , Quarantelli Mario , Bilo Leonilda , Piscitelli Valeria , Salvatore Elena , Ammendola Sara , Striano Salvatore , de Michele Giuseppe , Bonavita Vincenzo , Pappatà Sabina
Published: September 2007

We describe a case of adult‐onset biphasic Rasmussen's encephalitis who presented seizures and left dyskinesias at the onset and, after 1 year, language disorder. Serial MRI and [18F] FDG‐PET scans were performed showing involvement of the right cerebral hemisphere in the first phase and of the contralateral one in the second. © 2007 Movement Disorder Society
Myoclonus–dystonia syndrome: Clinical presentation, disease course, and genetic features in 11 families
Authors: Nardocci Nardo , Zorzi Giovanna , Barzaghi Chiara , Zibordi Federica , Ciano Claudia , Ghezzi Daniele , Garavaglia Barbara
Published: September 2007

Myoclonus–dystonia syndrome (MDS) is an inherited movement disorder with clinical and genetic heterogeneity. The epsilon sarcoglycan (SGCE) gene is an important cause of MDS. We report the results of a clinical and genetic study of 20 patients from 11 families. We disclosed six novel and two previously described mutations in nine families. The majority of patients had a phenotype of myoclonus and dystonia in combination, but clinical findings considered atypical, such a very early onset, distal myoclonus, and legs involvement, were detected in a significant proportion of cases. The disease course was variable, from progression to spontaneous remission of the motor symptoms. There were no obvious differences between mutation‐positive and ‐negative cases. © 2007 Movement Disorder Society
Artificial boundary conditions for viscoelastic flows
Authors: Nazarov Sergueï A. , Sequeira Adélia , Specovius‐Neugebauer Maria , Videman Juha H.
Published: September 2007

The steady three‐dimensional exterior flow of a viscoelastic non‐Newtonian fluid is approximated by reducing the corresponding nonlinear elliptic–hyperbolic system to a bounded domain. On the truncation surface with a large radius R, nonlinear, local second‐order artificial boundary conditions are constructed and a new concept of an artificial transport equation is introduced. Although the asymptotic structure of solutions at infinity is known, certain attributes cannot be found explicitly so that the artificial boundary conditions must be constructed with incomplete information on asymptotics. To show the existence of a solution to the approximation problem and to estimate the asymptotic precision, a general abstract scheme, adapted to the analysis of coupled systems of elliptic–hyperbolic type, is proposed. The error estimates, obtained in weighted Sobolev norms with arbitrarily large smoothness indices, prove an approximation of order O(R−2+ε), with any ε>0. Our approach, in contrast to other papers on artificial boundary conditions, does not use the standard assumptions on compactly supported right‐hand side f, leads, in particular, to pointwise estimates and provides error bounds with constants independent of both R and f. Copyright © 2007 John Wiley & Sons, Ltd.
Projector preconditioning for partially bound‐constrained quadratic optimization
Authors: Domorádová Marta , Dostál Zdeněk
Published: September 2007

Preconditioning by a conjugate projector is combined with the recently proposed modified proportioning with reduced gradient projection (MPRGP) algorithm for the solution of bound‐constrained quadratic programming problems. If applied to the partially bound‐constrained problems, such as those arising from the application of FETI‐based domain decomposition methods to the discretized elliptic boundary variational inequalities, the resulting algorithm is shown to have better bound on the rate of convergence than the original MPRGP algorithm. The performance of the algorithm is illustrated on the solution of a model boundary variational inequality. Copyright © 2007 John Wiley & Sons, Ltd.
Relationship between cribra orbitalia and enamel hypoplasia in the early medieval Slavic population at Borovce, Slovakia
Authors: Obertová Z. , Thurzo M.
Published: September 2007

Cribra orbitalia and enamel hypoplasia were examined in an early medieval (8th to beginning of 12th century AD) skeletal sample of 451 individuals from Borovce, Slovakia. More than 40% of these individuals died before reaching 20 years of age. The relationship between the occurrence of orbital and enamel lesions was analysed by focusing on the age‐specific distribution, and on its influence on demographic parameters. Both features were found in 11.2% of the observed skulls. The presence of orbital and dental lesions showed a considerable impact on mortality as well as the life expectancy. Generally, the highest mortality was observed among 0–4 year old individuals. The greatest discrepancy in the demographic parameters, however, appeared between the affected and unaffected individuals aged 10–14 and 15–19 years. In these two age groups the co‐occurrence of both lesions was most frequently recorded. These individuals obviously had a history of sickness, and thus could not cope with further bouts of disease and with the increased physiological demands of pubertal growth. The missing correlation in younger age categories can be largely explained by the difficulty of macroscopically examining the permanent dentition, since an interrelationship between the age at hypoplasia development and the occurrence of cribra orbitalia was detected. Several differences between the individuals with enamel defects and both conditions were observed in the distribution of age at hypoplasia formation. According to these results, several factors, such as impaired health status, growth demands and diet, influence the development of enamel hypoplasia and cribra orbitalia in a particular population. It is possible that after reaching a certain threshold, the underlying factors act synergistically in a kind of vicious cycle as the balance between the immune system, metabolism, and exogenous factors such as pathogens and nutrition, is disturbed. Copyright © 2007 John Wiley & Sons, Ltd.
Aggressive natural killer cell leukemia presenting with hemophagocytic lymphohistiocytosis
Authors: Petterson Toni E. , Bosco Annmarie A. , Cohn Richard J.
Published: September 2007

Aggressive natural killer cell leukemia (ANKL) is a very rare condition and when reported occurs almost exclusively in adults. We report a pediatric case of ANKL that presented with hemophagocytic syndrome, preceding the onset of leukemia by 12 weeks. Clinical and laboratory findings are discussed, along with morphology, immunophenotyping and cytogenetics, as well as the association with Epstein–Barr virus (EBV). This case is noteworthy for the expression of CD8 on the malignant cells, the cytogenetic findings that include abnormalities of chromosomes 6 and 7, as well as the age of the patient. Pediatr Blood Cancer 2008;50:654–657. © 2007 Wiley‐Liss, Inc.
Determination of camptothecins in DMSO extracts of Nothapodytes foetida by direct injection capillary electrophoresis
Authors: Hsiao Hsien‐Yi , Cheng Tzong‐Jih , Yang Ge‐Ming , Huang I‐Jen , Chen Richie L.C.
Published: September 2007

A rapid capillary electrophoresis procedure was developed for determining the anti‐cancer components, camptothecins, in Nothapodytes foetida. The hydrophobic compound was extracted from plant tissue (ca. 1 mL of DMSO for 100 mg of dried plant tissue) with a water‐miscible organic solvent, DMSO, at elevated temperature (60°C). The extract was directly injected into the separation capillary (untreated fused silica, 34 cm in length, 75 µm i.d.) and analysed in MEKC mode (369 nm). Within 5 min of migration, camptothecins were successfully separated and quantified by adding organic modifiers to the running buffer (20% DMSO, 90 mm SDS in 10 mm borate buffer, pH 8.60). The linear dynamic range for camptothecin was from 5 to 400 µg/mL. This method was proven to be very suitable for monitoring the amount of camptothecins during the cultivation of the medicinal plant. Copyright © 2007 John Wiley & Sons, Ltd.
Studies on the stability of diester‐diterpenoid alkaloids from the genus Aconitum L. by high performance liquid chromatography combined with electrospray ionisation tandem mass spectrometry (HPLC/ESI/MSn)
Authors: Yue Hao , Pi Zi‐feng , Li Hui‐lin , Song Feng‐rui , Liu Zhi‐qiang , Liu Shu‐ying
Published: September 2007

The stability of diester‐diterpenoid alkaloids (DDA) from plants of the genus Aconitum L. has been studied in different solvents and pH buffers. The HPLC/ESIMS method for analysing the concentration of DDA was established and DDA's decomposition products were elucidated by HPLC/ESI‐MS/MSn. In different solvents, e.g. dichloromethane, ether, methanol and distilled water, the decomposition pathways of DDA are quite different and their difference in stabilities depends on the difference of their structures, in which substituents at the N atom and substituents at C‐3 are different. The pyrolytic products of DDA, such as deacetoxy aconitine‐type alkaloids, have been observed in the above solvents, whereas 8‐methoxy‐14–benzoyl aconitine‐type alkaloids have been obtained only in methanol. Furthermore, the experimental results demonstrate that the stability of DDA depends on pH values of the buffer. Aconine as hydrolysate has been only found in pH 10.0 buffer, and the other hydrolysates and the pyrolyzates of DDA, such as benzoylaconine and deacetoxy aconitine, have been observed in all pH aqueous solutions. The decomposition pathways of DDA in buffers are related to the substituent on the C‐3 position. The decomposition pathway of aconitine is similar to that of mesaconitine, but different from that of hypaconitine. Copyright © 2007 John Wiley & Sons, Ltd.
Chromosome topology in normal and aneuploid blastomeres from human embryos
Authors: Diblík Jan , Macek Milan , Magli M. Cristina , Krejčí Roman , Gianaroli Luca
Published: September 2007

Objectives

To find whether chromosomes 13, 16, 18, 21, 22, X and Y in blastomeres of human embryos are nonrandomly localized, whether their aneuploidy affects their localization and if eventual early inactivation of chromosome X with peripheral localization is present.

Methods

Relative distances from the nucleus center and edge of 1198 fluorescence in situ hybridization signals in 98 human blastomeres were measured in digital images for comparison with a mathematical model of random distribution in spherical nucleus.

Results

Comparison with the mathematical model revealed that localization of chromosomes 13, 16, 21, 22, X and Y in normal and aneuploid blastomeres and that of chromosome 18 in normal blastomeres was not significantly different from random distribution. Similarly, chromosome X in blastomeres with more than one X did not appear to have a preferential localization. Only chromosome 18 in aneuploid blastomeres was differently distributed (p < 0.0001) with a shift to the nuclear periphery (p = < 0.0001).

Conclusions

Peripheral localization of chromosome 18 in aneuploid blastomeres is related to embryo aneuploidy. Conversely, a peripheral localization of the inactive X chromosome was not found in blastomeres from 3‐4 day old embryos. These results open the possibility to improve embryo selection after pre‐implantation diagnosis. Copyright © 2007 John Wiley & Sons, Ltd.
MRI with diffusion‐weighted imaging (DWI) and apparent diffusion coefficient (ADC) assessment in the evaluation of normal and abnormal fetal kidneys: preliminary experience
Authors: Savelli Sara , Di Maurizio Marco , Perrone Anna , Tesei Jacopo , Francioso Antonella , Angeletti Marco , La Barbera Laura , Ballesio Laura , de Felice Carlo , Porfiri Lucio Maria , Manganaro Lucia
Published: September 2007

Objective

To investigate apparent diffusion coefficient (ADC) mapping with the measurement of renal tissue ADC value of normal and pathological fetal kidneys at various gestational ages (GAs).

Methods

Fifty pregnant women underwent magnetic resonance images (MRI) after ultrasound (US) for suspected fetal genitourinary disorders (16) or for suspected disorders in other organs (34). A multiplanar study of urinary system was obtained by using conventional T2‐weighted sequences and echo planar imaging (EPI); Diffusion‐weighted images and ADC maps were evaluated. The renal tissue ADC value was measured for all normal and abnormal fetuses and related to GA.

Results

MRI confirmed urinary anomalies in 15 fetuses [2 renal developmental variants, 2 nephropathies, 4 multicystic dysplastic kidneys (MCDK), 7 renal tract dilatations] and detected normal kidneys in the remaining 35 fetuses. Normal renal parenchyma showed bright signal on diffusion‐weighted images with ADC values ranging from 1065 to 1327 µm2/s with a tendency to decrease over GA. A pathological ADC was detected in cases of bilateral MCDK, huge dilatations and in cases of nephropathies.

Conclusion

Diffusion‐weighted imaging (DWI) with ADC mapping can be used in the evaluation of fetal renal parenchyma and may become a tool of assessing function of the fetal kidney by means of measurement of renal tissue ADC values. Copyright © 2007 John Wiley & Sons, Ltd.
Prenatal diagnosis of a 9q34.3 microdeletion by array‐CGH in a fetus with an apparently balanced translocation
Authors: Simovich Marcia J. , Yatsenko Svetlana A. , Kang Sung‐Hae L. , Cheung Sau Wai , Dudek Martha E. , Pursley Amber , Ward Patricia A. , Patel Ankita , Lupski James R.
Published: September 2007

Objectives

Use high‐resolution genome analysis to clarify the genomic integrity in a fetus with a cytogenetically balanced translocation t(2;9)(q11.2;q34.3).

Methods

High resolution molecular cytogenetic analyses including G‐banded chromosome analysis, fluorescence in situ hybridization (FISH), and array‐comparative genomic hybridization (CGH) were performed on cultured cells, and DNA extracted from chorionic villus sample (CVS), amniotic fluid cells and fetal tissue. In addition, a custom fosmid‐based tiling path 9q34.3 microarray with a resolution of 35–40 kb was used for array‐CGH.

Results

GTG‐banding analysis showed an apparently balanced de novo translocation between the long arms of chromosomes 2 and 9; t(2;9)(q11.2;q34.3). Array‐CGH using a targeted chromosomal microarray analysis (CMA) uncovered a submicroscopic deletion of the subtelomeric region of 9q34.3 revealing the unbalanced nature of the rearrangement. These results were confirmed independently by FISH. The deletion was delimited to 2.7 Mb in size using the 9q34.3 fosmid‐based tiling path array‐CGH.

Conclusion

Array‐CGH is a powerful tool for rapid detection of genomic imbalances associated with microdeletion/duplication syndromes and for the evaluation of de novo apparently balanced translocation to enable high‐resolution genomic analysis at the breakpoints. Prenatal diagnosis of chromosomal rearrangements involving dosage‐sensitive genomic regions is an important adjuvant to prenatal care and provides more accurate information for counseling and informed decision making. Copyright © 2007 John Wiley & Sons, Ltd.
Simultaneous stretching and static electric field poling of poly(vinylidene fluoride‐hexafluoropropylene) copolymer films
Authors: Huan Yan , Liu Yayan , Yang Yifei
Published: September 2007

Poly(vinylideneflouride‐hexafluoropropylene) (PVDF‐HFP) copolymer films were simultaneously stretched and static electric poled (SSSEP) in seriate mode. The experimental results exhibited that SSSEP greatly enhanced the piezoelectric properties of the PVDF‐HFP films and slightly increased the dielectric properties of the films. The maximum piezoelectric coefficient d33 24 pC/N higher than the reported was obtained in these films under optimum condition. Based on the wide angle X‐ray diffraction results, the SSSEP films showed more organized crystalline structure than the only stretched films. POLYM. ENG. SCI., 47:1630–1633, 2007. © 2007 Society of Plastics Engineers
Rheological characterization of HDPE/sisal fiber composites
Authors: Mohanty Smita , Nayak Sanjay K.
Published: September 2007

The present paper summarizes an experimental study on the molten viscoelastic behavior of HDPE/sisal composites under steady and dynamic mode. Variations of the melt viscosity and die swell of the composites with an increase in shear rate, fiber loading, and coupling agent concentration have been investigated using capillary rheometer. The shear rate γ at the wall was calculated using Rabinowitsch correction applied to the apparent shear rate values. It was observed that the melt viscosity of the composites increased with the addition of fibers and maleic anhydride‐grafted PE (MAPE). Die swell of HDPE also decreased with the addition of sisal fibers and MAPE. Further, the dynamic viscoelastic behavior of the composites was measured employing parallel plate rheometer. Time–temperature superposition was applied to generate various viscoelastic master curves. Temperature sweeps were also carried out to study the flow activation energy determined from Arrhenius equation. The fiber–matrix morphology of the extrudates was also examined using scanning electron microscopy. POLYM. ENG. SCI., 47:1634–1642, 2007. © 2007 Society of Plastics Engineers
Mathematical modeling of the molecular weight distribution of polypropylene produced in a loop reactor
Authors: Luo Zheng‐Hong , Zheng Yi , Cao Zhi‐Kai , Wen Shao‐Hua
Published: September 2007

The model of the molecular weight distribution (MWD) of polypropylene produced in a loop reactor is established. The simulated MWD data of the polymers produced in steady‐state polymerizations agree with the actual data collected from certain plant. The simulated weight‐average molecular weight data also agree with the plant data in start‐up processes. Furthermore, the model can be used to simulate the influence of the operation parameters on the MWD of the polymers produced in the steady‐state polymerizations as well as the dynamic polymerizations. The simulated results of the steady state polymerizations show the MWD width of polypropylene decreases with the increase of both the propylene flow and the hydrogen flow, but increases with the increase of the catalyst flow. We also find the weight fraction of the polymers with short chains increases with the increase of both the propylene flow and the hydrogen flow, meanwhile, a small shift of the MWD curve to long chains can also be found as the catalyst flow increases. In the dynamic polymerizations, simulations indicate the MWD width and the weight fraction of the polymers with long chains all decrease in both of the start‐up process and the end‐up process of the polymerizations. POLYM. ENG. SCI., 47:1643–1649, 2007. © 2007 Society of Plastics Engineers
Surface roughness and light transmission of biaxially oriented polypropylene films
Authors: Lin Y.J. , Dias P. , Chum S. , Hiltner A. , Baer E.
Published: September 2007

The effect of thermal history on the transparency of biaxially‐oriented polypropylene (BOPP) films was investigated. Compression molded sheets prepared with different cooling rates were biaxially oriented at several temperatures. Correlations were sought between the light transmission measured at 633 nm and the surface roughness as characterized by atomic force microscopy. It was determined that surface roughness on the 100‐μm size scale was responsible for a loss in transparency. Surface roughness on the submicron size scale did not affect the transparency. The clearest films were obtained from compression molded sheets with the most homogeneous texture and by orienting at the lowest temperature. POLYM. ENG. SCI., 47:1658–1665, 2007. © 2007 Society of Plastics Engineers
Study on grafting maleic anhydride onto polypropylene in microcolloid systems by coirradiation
Authors: Tan Xiumin , Xu Yongshen , Qian Jun , Wang Chonglin
Published: September 2007

Grafting of maleic anhydride (MAH) onto polypropylene (PP) performed in microcolloid systems by coirradiation was studied in this paper. First, the microcolloid of PP and MAH in xylene was prepared and its dynamic light scattering (DLS) shows particle size distributions of microcolloid system in 4–6 μm. Second, the effect of irradiation dose and monomer concentration on the amount of grafted MAH was investigated. The results show that the coirradiation in microcolloid systems can obviously cause an increase of the amount of grafted MAH. The percentage of grafting of the product amounts to 5.24%. The molecular structures of grafted MAH prepared were characterized by Fourier‐transform infrared spectroscopy. Differential scanning calorimetry and wide‐angle X‐ray diffraction were used to determine the degree of crystallinity and crystalline structure. POLYM. ENG. SCI., 47:1703–1707, 2007. © 2007 Society of Plastics Engineers
A test method for studying the rolling resistance of rubber compounds
Authors: Gent A.N. , Gallagher D.D. , Steven R.B.
Published: September 2007

A test method is described for measuring energy losses in rolling, using the damped oscillations of a pendulum that makes a rigid cylinder roll backwards and forwards across a rubber block (Gent et al. U.S. Patent No. 6,494,076 B1, The Goodyear Tire and Rubber Company, December 17 (2002)). The mechanics of small swings, in which the displacement of the contact patch is smaller than its length, are shown to be different from those governing swings of larger amplitude. Thus, starting with relatively large swings of the pendulum, the amplitude of oscillation decays initially at a constant rate and then changes to a decreasing rate as the swings become small. In principle, the two processes provide separate measures of the energy losses in rolling. The proposed test method may be useful for studying the effects of the surface features of tire treads and road surfaces on tire rolling resistance, in addition to characterizing the dissipative properties of rubber compounds. POLYM. ENG. SCI., 47:1576–1579, 2007. © 2007 Society of Plastics Engineers
Preparation of intercalating agent‐free epoxy/clay nanocomposites
Authors: Sun Luyi , Boo Woong J. , Liu Jia , Tien Chi‐Wei , Sue Hung‐Jue , Marks Maurice J. , Pham Ha
Published: September 2007

A simple intercalating agent‐free approach to prepare epoxy/montmorillonite (MMT) clay nanocomposite is reported. Through this new approach, no organic modifiers are needed. Thus, the cost for preparing polymer nanocomposites can be significantly reduced. The extent of dispersion and exfoliation of clay in epoxy was characterized by X‐ray diffraction and transmission electron microscopy observations. It is found that the MMT clay is well‐dispersed in epoxy matrix. The clay platelets in epoxy show a stacked structure with dimensions of about 1–2 μm in length and about 20 nm in thickness. At 4.5 wt% of clay loading level, the flexural modulus of the epoxy nanocomposite is increased by about 35%. No reduction in fracture toughness or glass‐transition temperature is observed. The implication of the present finding for commercialization of polymer nanocomposites is discussed. POLYM. ENG. SCI., 47:1708–1714, 2007. © 2007 Society of Plastics Engineers
Effects of clay on the morphology of poly(acrylonitrile‐butadiene‐styrene) and polypropylene nanocomposites
Authors: Sung Y.T. , Kim Y.S. , Lee Y.K. , Kim W.N. , Lee H.S. , Sung J.Y. , Yoon H.G.
Published: September 2007

The effects of clay on the morphology of the poly(acrylonitrile‐butadiene‐styrene) (ABS)/polypropylene (PP) nanocomposites were investigated. From the studies of wide angle X‐ray diffraction (WAXD) and transmission electron microscopy (TEM) analysis of the ABS/PP (70/30) nanocomposites with clay, it was observed that most of the clay existed in the ABS matrix because of the good affinity between the ABS and clay which contained benzyl group. From the studies of the scanning electron microscopy (SEM) analysis, the size of the PP droplet decreased with clay from 16.7 to 5.6 μm when the clay was added up to 4.0 phr. When the clay content was increased, the droplet of the dispersed phase (PP) was shown to elongated structure. The elongated structure could be explained by the decrease of the viscosity ratio of the PP and continuous phase (ABS) with clay, which corresponded to the increase of the viscosity of the continuous phase (ABS/clay). From the results of the SEM, TEM, and WAXD analysis, it is suggested that the increase of the viscosity of the continuous phase (ABS/clay) is mainly due to the location of clay in the ABS matrix. POLYM. ENG. SCI., 47:1671–1677, 2007. © 2007 Society of Plastics Engineers
Discontinuous deformation in an elastic material. Part 1. Energy dissipative and storage applications
Authors: Raman Arun , Farris Richard J.
Published: September 2007

The concept of energy or work dissipation from a perfectly elastic material, due to a discontinuous deformation mechanism, is developed in this study. Dissipation occurs even from a perfectly elastic material, preferably an elastomer, when subjected to a discontinuous “jump” stretch or “jump” contraction. Stretching an elastomeric member through free extension requires a large amount of work. Such a sudden jump stretch of an elastic material is difficult to accomplish and is equivalent to thermodynamic free compression of a gas. The amount of work required can greatly exceed the strain energy stored in the material if the extension were applied without the jump or “shock” process. Interestingly, only part of the stored energy is recovered on unloading the elastomer the same way (through contraction). Excess work lost in contraction dissipates as heat but is not due to the common viscoelastic/plastic losses associated with internal friction in solids. Dissipation is possible even from a perfectly elastic material. Energy values associated in this jump deformation process are independent of the stress–strain curve path, and depend only on initial and final states for the material. Heat dissipation from an elastic rubber belt is examined and some applications extended from the developed principle are enunciated. POLYM. ENG. SCI., 47:1511–1520, 2007. © 2007 Society of Plastics Engineers