bluuebunny/crossref_metadata_2025 huggingface dataset:
Non‐differentiability points of Cantor functions
Authors: Li Wenxia
Published: December 2006

Let the Cantor set C in ℝ be defined by C = ∪r j =0 hj (C) with a disjoint union, where the hj 's are similitude mappings with ratios 0 < aj < 1. Let μ be the self‐similar Borel probability measure on C corresponding to the probability vector (p 0, p 1, …, pr). Let S be the set of points at which the probability distribution function F (x) of μ has no derivative, finite or infinite. For the case where pi > ai we determine the packing and box dimensions of S and give an approach to calculate the Hausdorff dimension of S. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterizations of weighted Besov spaces
Authors: Pradolini G. , Viviani B.
Published: December 2006

We define a class of weighted Besov spaces and we obtain a characterization of this class by means of an appropriate class of weighted Lipschitz ϕ spaces. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interior regularity criterion via pressure on weak solutions to the Navier–Stokes equations
Authors: Suzuki Tomoyuki
Published: December 2006

Consider the nonstationary Navier–Stokes equations in Ω × (0, T), where Ω is a bounded domain in ℝ3. We prove interior regularity for suitable weak solutions under some condition on the pressure in the class of scaling invariance. The notion of suitable weak solutions makes it possible to obtain better information around the singularities. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fundamental Aspects of Measuring Copolymerization Reactivity Ratios Using Real‐Time FTIR Monitoring
Authors: Puskas Judit E. , McAuley Kimberley B. , Chan S. W. Polly
Published: December 2006

Real‐time FTIR is a powerful tool to obtain copolymerization reactivity ratios because it allows simultaneous monitoring of individual monomer consumption rates. Based on the Mayo‐Lewis equation we showed that in reactivity ratios can be defined as the ratios of apparent rate constants of monomer consumption. The validity and limitations on this new method are discussed in the isobutylene‐isoprene and isobutylene‐styrene carbocationic copolymerization systems.
Kinetic Modeling of Non‐Linear Polymerization
Authors: Costa Mário Rui P. F. N. , Dias Rolando C. S.
Published: December 2006

Recent developments of a method based upon population balances of generating functions of polymer chain length distributions (CLD) are presented. The calculation of the CLD and how to take into account chain length dependent reactivity are discussed. Prediction of polymer properties is also possible but only easily done for the average molecular radius of gyration; some results are presented for a radical polymerization including transfer to polymer and propagation with terminal double bonds.
Monte Carlo Simulation of Ethylene Copolymers: A Look into the Monomer Sequence Distribution
Authors: Al‐Saleh Mohammad A. , Simon Leonardo C.
Published: December 2006

A comprehensive mathematical model was developed using Monte Carlo simulation to describe the mechanism of ethylene and α‐olefin copolymerization. The model studies the polymerization mechanism using coordination catalysts and is able to predict molecular weight and detailed chemical composition distributions. This work is considered to be a useful tool that enables us to understand and described the monomer sequence distribution as a function of chain length in semi‐batch polymerization reactors.
Population Balance Model for Emulsion Polymerisation Under Pseudo‐Bulk Conditions: Combined Particle Size Distribution and Molecular Weight Distribution
Authors: Sweetman Stephen J. , Immanuel Charles D. , Malik Tahir , Emmett Simon , Williams Neal
Published: December 2006

A comprehensive model for emulsion polymerisation is presented, accounting for particle size distribution (PSD) and molecular weight distribution (MWD). The PSD information is incorporated through a population balance framework. A mechanistic formulation is adopted in modelling the average number of radicals/particle under pseudo‐bulk compartmentalisation conditions. The method of moments is adopted to simplify the MWD equations over each discrete size class. The impact of the pseudo‐bulk assumption on the PSD and MWD results is assessed. An identification of potential manipulated variables for control of PSD and MWD is done through sensitivity analysis.
Estimation of Free Radical Polymerization Rate Coefficients Using Computational Chemistry
Authors: Bebe Siziwe , Yu Xinrui , Hutchinson Robin A. , Broadbelt Linda J.
Published: December 2006

This study explores the application of computational chemistry to estimate free radical polymerization rate coefficients. The Evans‐Polanyi relationship is combined with computed heats of polymerization to estimate copolymerization reactivity ratios for many vinyl monomer pairs, focusing on acrylates, methacrylates and styrene, with accuracy assessed by comparison to experimental values. The effect of different optimization approaches on the values of thermodynamic properties is explored, and it is concluded that a combination of conventional optimization and relaxed potential energy scans was most effective at identifying global minima. The difference between thermodynamic properties calculated using the harmonic oscillator treatment and a hindered rotor model is evaluated for methyl methacrylate polymerization.
Synthesis of Poly(Vinyl Alcohol) and/or Poly(Vinyl Acetate) Particles with Spherical Morphology and Core‐Shell Structure and its Use in Vascular Embolization
Authors: Peixoto Luciana S. , Silva Fabricio M. , Niemeyer Mariana A. L. , Espinosa Gaudencio , Melo Príamo A. , Nele Márcio , Pinto José Carlos
Published: December 2006

Poly(vinyl alcohol), PVA, is the most frequently used material in embolization of tumors, aneurisms and arteriovenous malformations due to its low toxicity, good biocompatibility and desirable physical properties. It is well known that PVA particles cannot be prepared by direct polymerization of vinyl alcohol. Its synthesis is typically performed by the suspension polymerization of vinyl acetate to produce poly(vinyl acetate), PVAc, followed by the saponification of the PVAc particles. This work shows that, using the suspension polymerization technique, it is possible to obtain spherical particles with a core‐shell structure of PVA/PVAc with regular morphology, instead of particles with irregular shapes and sizes, as usually found in many commercial embolization products. Therefore, this work presents the production of PVA/PVAc spherical particles that can be used to occlude blood vessels, eliminating the disadvantages of commercial PVA. In vivo clinical tests with white “New Zealand” rabbits undergoing kidney inflammation reaction have shown that these spherical particles are much more efficient for vascular embolization.
An Integrated Model‐Based Analysis of Polymer Chemistry and Polymerisation Reactors
Authors: Immanuel Charles D. , Steinke Joachim H. G. , Higgins Julia S.
Published: December 2006

In this paper, a simple demonstration is presented on the analysis of the combined effect of polymer chemistry and the polymerisation reactor on the polymer properties. The model would ideally account for the raw material and end‐product characteristics and properties on the one hand; the polymerisation kinetics and reaction engineering on the other hand. This system‐wide model‐driven approach enables the interlinking of the widely disparate facets of polymer science and engineering, and thereby provides a tool for rapid and efficient identification and scale‐up of new polymeric materials that would be exploited in future studies. The ideas are demonstrated with regard to a hyper‐branched polymerisation chemistry.
Formation of Nanostructures in Multi Component Systems Based on Organic Polymer and Coordination Metal Compound
Authors: Kozak Nataly , Nizelskii Yurij , Mnikh Nadya , Shtompel Vladimir , Grischuk Oleg
Published: December 2006

Structuring of polyurethane (PU) networks is analyzed under influence of transition metal coordination compounds: mono‐ionic β‐diketonates and polyheteronuclear metal‐organic complexes. Formed in situ nanostructures both organic and inorganic were found in organic polymer modified with coordination metal compound. Influence of coordination junction point spatial symmetry and content of metal ion in modifier on structure and dielectric characteristics of modified PUs is analyzed using X‐ray, EPR, SEM and transmission optical microscopy, DRS and DSC methods.
Synthesis of Bimodal PVC Latexes by Emulsion Polymerization: An Experimental and Modeling Study
Authors: Vale Hugo M. , McKenna Timothy F.
Published: December 2006

The onset and extent of secondary particle formation in the seeded emulsion polymerization of vinyl chloride were investigated by performing a series of seeded polymerizations at different concentrations of seed latex and surfactant. It was found that, in general, both the onset and the extent of secondary particle formation are determined not only by the rate of homogeneous nucleation, but also by the rates of particle coagulation. A comparison of methods to compute the evolution of the particle size distribution in vinyl chloride emulsion polymerization was also carried out. For growth processes, the widely‐used pseudo‐bulk model gives correct answers. For processes involving particle formation, on the other hand, this model cannot be used because it neglects, among others, the effects of nucleation and coagulation on the radical number distribution. To surmount this problem, we propose to use the zero‐one‐two model, for which the full population balance equations are given here.
Polymerization Compounding on the Surface of Zirconia Nanoparticles
Authors: Esmaeili Babak , Chaouki Jamal , Dubois Charles
Published: December 2006

Zirconia nanoparticles were encapsulated by polyethylene via a polymerization compounding method using a Ziegler‐Natta catalyst. The chemical reaction was carried out in an organic solvent under moderate pressure of ethylene monomer. Transmission electron microscopy (TEM) indicated the presence of a thin layer of polymer, about 6 nm, uniformly applied around the particles. However, the thickness of coating layer can be controlled as a function of time and operating conditions of the process. The morphology study using scanning electron microscopy (SEM) as well as TEM revealed that although the nanoparticles seem to be coated individually, some agglomerates, encapsulated by a polymer film, could be observed. The grafting of the catalyst to the original surface of particles was further confirmed by X‐ray photoelectron spectroscopy (XPS).
A Single‐Gallery Model for the In Situ Production of Polyethylene‐Clay Nanocomposites
Authors: Maneshi Abolfazl , Soares João B. P. , Simon Leonardo C.
Published: December 2006

Polyolefin‐clay nanocomposites are finding many new applications because of their improved properties, such as high modulus, elevated scratch resistance and low gas permeability. Currently, these composites are produced by melt blending organically modified clay with polyolefins. The most challenging step in this process is the intercalation and exfoliation of the clay to produce a homogenously dispersed phase at the nanoscale. A promising alternative to melt blending is in‐situ polymerization, where the polymer is produced between the clay layers in the polymerization reactor. In‐situ polymerization of olefins with metallocene catalysts supported on clay can produce nanocomposites using conventional polymerization reactors, provided that the clay can be used as a support for the olefin polymerization catalyst. In this approach, the clay fulfills the functions of catalyst support and dispersed phase in the final nanocomposite. In this work, a mathematical model describing particle growth during in‐situ polymerization of ethylene with a metallocene catalyst supported on clay will be discussed. The model expands the approach of the multi‐grain model used in heterogeneous olefin polymerization to account for the layered structure of clays.
Modulation of UVB‐induced and basal cyclooxygenase‐2 (COX‐2) expression by apigenin in mouse keratinocytes: Role of USF transcription factors
Authors: Van Dross Rukiyah T. , Hong Xiaoman , Essengue Suzanne , Fischer Susan M. , Pelling Jill C.
Published: December 2006

Apigenin is a bioflavonoid with chemopreventive activity against UV‐ or chemically‐induced mouse skin tumors. To further explore the mechanism of apigenin's chemopreventive activity, we determined whether apigenin inhibited UVB‐mediated induction of cyclooxygenase‐2 (COX‐2) expression in mouse and human keratinocytes. Apigenin suppressed the UVB‐induced increase in COX‐2 protein and mRNA in mouse and human keratinocyte cell lines. UVB radiation of keratinocytes transfected with a mouse COX‐2 promoter/luciferase reporter plasmid resulted in a threefold increase in transcription from the promoter, and apigenin inhibited the UV‐induced promoter activity at doses of 5–50 µM. Transient transfections with COX‐2 promoter deletion constructs and COX‐2 promoter constructs containing mutations in specific enhancer elements indicated that the effects of UVB required intact Ebox and ATF/CRE response elements. Electrophoretic mobility shift assays with supershifting antibodies were used to identify USF‐1, USF‐2, and CREB as proteins binding to the ATF/CRE‐Ebox responsive element of the COX‐2 promoter. Keratinocytes co‐transfected with the COX‐2 luciferase reporter and a USF‐2 expression vector, alone or in combination with a USF‐1 expression vector, exhibited enhanced promoter activity in both UVB‐irradiated and nonirradiated cultures. However, COX‐2 promoter activity was inhibited in keratinocytes co‐transfected with USF‐1 alone. Finally, we present data showing that the suppressive effect of apigenin on COX‐2 expression could be reversed by co‐expression of USF‐1 and USF‐2. These results suggest that one pathway by which apigenin inhibits COX‐2 expression is through modulation of USF transcriptional activity. © 2006 Wiley‐Liss, Inc.
Bone marrow mononuclear cells stimulate angiogenesis when transplanted into surgically induced fibrocollagenous tunnels: Results from a canine ischemic hindlimb model
Authors: Padilla Luis , Krötzsch Edgar , De La Garza Anabel S. , Figueroa Siegfried , Rodriguez‐Trejo Juan , Ávila Gerardo , Schalch Paul , Escotto Ignacio , Glennie Germán , Villegas Fernando , Di Silvio Mauricio
Published: December 2006

Progenitor cell transplantation has been considered as a potential angiogenesis therapy for the ischemic hindlimb. In this work we performed an ischemic hindlimb model in dogs. We ligated the middle sacra and the external right iliac arteries. After 7 days, the femoral artery was ligated and removed, and three Silastic® tubes were inserted into the gracilis muscle to create fibrocollagenous tunnels. After Silastic® implantation, we administered saline or granulocyte colony stimulating factor (G‐CSF) subcutaneously daily during 5 days. Fourteen days after device positioning we transplanted bone marrow mononuclear cells (BMMC) into the tunnels previously formed by Silastic® tube reaction. Twenty‐eight days later, contrasted angiographies were performed and angiographic scores were calculated. Also, vessels and endothelial cells and proliferating cells were identified by immunochemistry of muscle sections. Results demonstrated that BMMC transplantation enriched by G‐CSF administration significantly stimulates angiogenesis in the ischemic hindlimb, and more than BMMC transplantation alone. Transplantation of progenitor cells in an appropriate extracellular matrix is a potential therapy for hindlimb ischemia. © 2006 Wiley‐Liss, Inc. Microsurgery, 2007.
Beneficial effects of dithiothreitol on relative levels of glutathione S‐transferase activity and thiols in oocytes, and cell number, DNA fragmentation and allocation at the blastocyst stage in the mouse
Authors: Rausell Francisco , Pertusa José F. , Gómez‐Piquer Vanessa , Hermenegildo Carlos , García‐Pérez Miguel A. , Cano Antonio , Tarín Juan J.
Published: December 2006

We analyzed the effect of in vitro aging of mouse oocytes in the presence of dithiothreitol (DTT) on relative levels of glutathione S‐transferase (GST) activity and thiols in oocytes, and cell number, DNA fragmentation and cellular allocation to the inner cell mass (ICM) and trophectoderm (TE) lineage at the blastocyst stage. Ovulated oocytes from gonadotropin primed hybrid female mice of 6–8 weeks of age were aged in vitro in the presence of 0, 5, 50, or 500 µM DTT for 6 hr prior to insemination. Relative levels of GST activity and thiols in oocytes were determined by confocal laser scanning microscopy, DNA fragmentation using a single‐step TUNEL method, and cell allocation to the ICM and TE lineage by blastocyst staining with propidium iodide and Hoechst 33258. Non‐aged oocytes exhibited higher relative levels of GST activity and thiols when compared to oocytes aged in the presence of 0, 5, and 50 µM DTT. Day 5 blastocysts from the 5, 50, and 500 µM DTT groups exhibited higher total number of cells, number of ICM cells, and ICM/TE ratio, but lower percentage of number of nuclei with DNA fragmentation/number of ICM cells than blastocyst from the 0 µM DTT group. These data show that DTT counteracts the negative effects of a post‐ovulatory aging of mouse oocytes in vitro on relative levels of GST activity and thiols in oocytes, and percentage of number of nuclei with DNA fragmentation/number of ICM cells, total number of cells, number of ICM cells and ICM/TE ratio in Day 5 blastocysts. Mol. Reprod. Dev. 74: 860–869, 2007. © 2006 Wiley‐Liss, Inc.
Impact of cryopreservation and reactive oxygen species on DNA integrity, lipid peroxidation, and functional parameters in ram sperm
Authors: Peris Soliman I. , Bilodeau Jean‐François , Dufour Maurice , Bailey Janice L.
Published: December 2006

Assisted reproduction using frozen‐thawed semen has practical advantages, although cryopreservation is detrimental to sperm fertility in most mammals. We examined the influence of cryopreservation and reactive oxygen species (ROS) on ram sperm DNA stability (using SCSA), lipid peroxidation (LPO), chlortetracycline fluorescence (CTC) patterns, motility and viability. In Experiment 1, DNA integrity, LPO, CTC, motility and viability tests were performed on fresh and cryopreserved sperm after 0, 6, and 24 hr in synthetic oviductal fluid (SOF). In Experiment 2, fresh sperm were incubated in serum‐free SOF (SOF‐S; 1, 4, and 24 hr) with 0, 50, 150, or 300 µM H2O2 then assayed. Cryopreservation increased the percentage of sperm with a high DNA fragmentation index (%DFI), decreased the percentages of motile and viable sperm at thawing (0 hr), but did not affect LPO. H2O2 (150 or 300 µM) increased %DFI after 24 hr. LPO or sperm viability were not affected by H2O2, although most motility parameters decreased. H2O2 decreased the percentage of chlortetracycline pattern F sperm at 4 hr and increased the percentage of acrosome‐reacted sperm (pattern AR) after 1 hr. Pooled data of Experiment 2 showed LPO was positively correlated with SCSA (r = 0.29 to r = 0.59; P < 0.05 to P < 0.01), while most motility parameters and the percentage of viable sperm were negatively correlated with LPO (r = −0.30 to r = −0.38; P < 0.05 to P < 0.01). LPO was positively correlated with the percentage of pattern AR sperm (r = 0.33; P < 0.01). Cryopreservation and H2O2 promote DNA instability in ram sperm, though motility is a more sensitive indicator of oxidative stress than the other parameters investigated. Mol. Reprod. Dev. 74: 878–892, 2007. © 2006 Wiley‐Liss, Inc.
Optimal sample size allocation for tests with multiple levels of stress with extreme value regression
Authors: Ng H. K. T. , Balakrishnan N. , Chan P. S.
Published: December 2006

In this article, we discuss the optimal allocation problem in a multiple stress levels life‐testing experiment when an extreme value regression model is used for statistical analysis. We derive the maximum likelihood estimators, the Fisher information, and the asymptotic variance–covariance matrix of the maximum likelihood estimators. Three optimality criteria are defined and the optimal allocation of units for two‐ andk‐stress level situations are determined. We demonstrate the efficiency of the optimal allocation of units in a multiple stress levels life‐testing experiment by using real experimental situations discussed earlier by McCool and Nelson and Meeker. Monte Carlo simulations are used to show that the optimality results hold for small sample sizes as well. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007
Hunter‐gatherer use of small animal food resources: coprolite evidence
Authors: Reinhard K. J. , Ambler J. R. , Szuter C. R.
Published: December 2006

Faunal remains are commonly found in coprolites and provide direct evidence of animal consumption. An evaluation of hunter‐gatherer coprolites from the Southwest US shows that animal bone in coprolites can be used to assess patterns of hunting, food preparation, and general importance of small animals in diet. This is demonstrated by a comparison of faunal assemblages between two hunter‐gatherer sites with respect to small animal hunting strategies. The sites are Dust Devil Cave on the Colorado Plateau, an Archaic winter habitation, and Hinds Cave, a warm season Archaic habitation in the lower Pecos of Texas. The results indicate that small animal hunting varied regionally and seasonally. Copyright © 2006 John Wiley & Sons, Ltd.
Low gammaglobulin subclass 2 levels in paediatric cystic fibrosis patients followed over a 2‐year period
Authors: Garside J.P. , Kerrin D.P. , Brownlee K.G. , Gooi H.C. , Taylor J.M. , Conway S.P.
Published: December 2006

The aim of this study was to relate serum immunoglobulin G2 subclass levels in a large paediatric population with cystic fibrosis, to clinical status and antibody levels to Haemophilus influenzae type b and Streptococcus pneumoniae and to observe any changes over a 2‐year period. IgG subclasses were measured in 131 patients. Results were compared with levels from age‐related normal population data. The following clinical data were collected at baseline and 2 years later; genotype: height, weight, and BMI z‐scores: FEV1 (as percent predicted): Shwachman–Kulczcyki and Northern chest X‐ray scores: Pseudomonas aeruginosa status. Antibody levels to H. influenzae type b and S. pneumoniae measured at baseline were related to IgG2 level. There was a reduction in the prevalence of low levels of IgG2 from 29% to 10% over the 2‐year period. Low levels of IgG2 were not associated with any decline in clinical well‐being. Low levels of IgG2 alone were associated with low antibody levels to S. pneumoniae. Low levels of IgG2 and low levels of antibody to H. influenzae and S. pneumoniae were not associated with any decline in clinical well‐being. Children with high levels of IgG2 had worse lung function, worse Shwachman–Kulczcyki and Northern chest X‐ray scores and higher levels of P. aeruginosa infection. Children with low IgG2 levels were not worse clinically compared to those with normal or high IgG2 levels. High IgG2 levels were associated with a worse clinical status. Pediatr Pulmonol. 2007; 42:125–130. © 2006 Wiley‐Liss, Inc.
Lung function and exhaled nitric oxide levels in infants developing chronic lung disease
Authors: Williams Olivia , Dimitriou Gabriel , Hannam Simon , Rafferty Gerrard F. , Greenough Anne
Published: December 2006

Chronic lung disease (CLD) is a common outcome of neonatal intensive care. To determine whether the results of serial exhaled nitric oxide (eNO) measurements during the perinatal period differed between infants who did and did not develop CLD. In addition, we wished to assess whether eNO results were more predictive of CLD development than lung function test results or readily available clinical data (gestational age and birthweight). The patients were 24 infants with a median gestational age of 27 (range 25–31) weeks. Measurements of eNO levels, functional residual capacity (FRC), and compliance of the respiratory system (CRS) were attempted on postnatal days 1, 3, 5, 7, 14, and 28 days. The 12 infants who developed CLD were of significantly lower birthweight and gestational age than the rest of the cohort; in addition, they had lower median FRC (P < 0.02) and CRS (P < 0.02) results, but not higher eNO levels, in the first week after birth. Construction of receiver operator characteristic (ROC) curves demonstrated that the CRS and FRC results on Day 3 were the best predictors of CLD development; the areas under the ROC curves were 0.94 and 0.91, respectively. Early lung function test results, but not eNO levels, are useful in predicting CLD development, but are not significantly better than birthweight. Pediatr Pulmonol. 2007; 42:107–113. © 2006 Wiley‐Liss, Inc.
Assessing bronchial responsiveness to hypertonic saline using the stepwise protocol of phase two of the international study of asthma and allergies in childhood (ISAAC II)
Authors: Büchele Gisela , Rzehak Peter , Weinmayr Gudrun , Keil Ulrich , Leupold Wolfgang , von Mutius Erika , Weiland Stephan K.
Published: December 2006

Measurement of bronchial responsiveness to hypertonic saline was applied in 22 study centers worldwide as part of Phase Two of the International Study of Asthma and Allergies in Childhood (ISAAC Phase Two). Because the amount of inhaled saline was difficult to standardize during the stepwise protocol with inhalation periods of increasing duration, we evaluated different statistical procedures based on inhalation time in relation to wheeze and current asthma. Data on random samples on 9 to 11‐year‐old children (n = 1,418) from two German centers were analyzed. The following statistical approaches were evaluated: (1) bronchial hyperreactivity (BHR) defined dichotomously as a fall in FEV1 (forced expiratory volume in 1 s) ≥15%; (2) PT15: the provocation time causing BHR using survival‐analyses methods; (3) time‐response‐slope (continuous) of the individual FEV1‐courses calculated by a linear model after comparing different mathematical models. The sensitivity and specificity of BHR versus current asthma were 47% and 87%, respectively. Analyses of the provocation time indicated an increased risk (adjusted hazard‐ratio: 4.3; 95% CI: 2.8–6.5) for a fall in FEV1 ≥ 15% among children with current asthma in comparison to those without. The time‐response‐slope differed markedly between children with and without wheeze and current asthma (P < 0.0001). BHR is meaningful and relatively easy to use, but has low sensitivity. Time‐response‐slopes utilize the available information from the stepwise protocol better than BHR and survival‐analysis based on PT15. Response parameters based on inhalation time discriminate well between children with and without asthma and will be compared in the analyses of ISAAC Phase Two data. Pediatr Pulmonol. 2007; 42:131–140. © 2006 Wiley‐Liss, Inc.
Massive hemoptysis in an 11‐year‐old girl with isolated pulmonary arteritis
Authors: Chan E.Y. , Avcin T. , Dell S. , Manson D. , Cutz E. , Schneider R. , Ratjen F.
Published: December 2006

A 10‐year‐old girl developed recurrent bouts of massive hemoptysis over a 9‐month period. No obvious bleeding source was detected. Her pulmonary angiogram showed a pulmonary aneurysm of the second branch of the left main pulmonary artery as well as widespread irregularities of the pulmonary arteries including areas of stenosis and pruning. Elective embolization of the aneurysm did not control hemoptysis and emergency left upper lobectomy had to be performed. Histology showed large artery wall injury with acute leucocytoclastic inflammation, fibrinoid necrosis, granulomatous inflammation, and ectasia of vessel wall. This combination of abnormalities has not been described to date and represents the first case of isolated pulmonary arteritis in children prior to puberty. Pediatr Pulmonol. 2007; 42:177–180. © 2006 Wiley‐Liss, Inc.
Evaluating protein structures determined by structural genomics consortia
Authors: Bhattacharya Aneerban , Tejero Roberto , Montelione Gaetano T.
Published: December 2006

Structural genomics projects are providing large quantities of new 3D structural data for proteins. To monitor the quality of these data, we have developed the protein structure validation software suite (PSVS), for assessment of protein structures generated by NMR or X‐ray crystallographic methods. PSVS is broadly applicable for structure quality assessment in structural biology projects. The software integrates under a single interface analyses from several widely‐used structure quality evaluation tools, including PROCHECK (Laskowski et al., J Appl Crystallog 1993;26:283–291), MolProbity (Lovell et al., Proteins 2003;50:437–450), Verify3D (Luthy et al., Nature 1992;356:83–85), ProsaII (Sippl, Proteins 1993;17: 355–362), the PDB validation software, and various structure‐validation tools developed in our own laboratory. PSVS provides standard constraint analyses, statistics on goodness‐of‐fit between structures and experimental data, and knowledge‐based structure quality scores in standardized format suitable for database integration. The analysis provides both global and site‐specific measures of protein structure quality. Global quality measures are reported as Z scores, based on calibration with a set of high‐resolution X‐ray crystal structures. PSVS is particularly useful in assessing protein structures determined by NMR methods, but is also valuable for assessing X‐ray crystal structures or homology models. Using these tools, we assessed protein structures generated by the Northeast Structural Genomics Consortium and other international structural genomics projects, over a 5‐year period. Protein structures produced from structural genomics projects exhibit quality score distributions similar to those of structures produced in traditional structural biology projects during the same time period. However, while some NMR structures have structure quality scores similar to those seen in higher‐resolution X‐ray crystal structures, the majority of NMR structures have lower scores. Potential reasons for this “structure quality score gap” between NMR and X‐ray crystal structures are discussed. Proteins 2007. © 2006 Wiley‐Liss, Inc.
Protein–RNA interactions: Structural analysis and functional classes
Authors: Ellis Jonathan J. , Broom Mark , Jones Susan
Published: December 2006

A data set of 89 protein–RNA complexes has been extracted from the Protein Data Bank, and the nucleic acid recognition sites characterized through direct contacts, accessible surface area, and secondary structure motifs. The differences between RNA recognition sites that bind to RNAs in functional classes has also been analyzed. Analysis of the complete data set revealed that van der Waals interactions are more numerous than hydrogen bonds and the contacts made to the nucleic acid backbone occur more frequently than specific contacts to nucleotide bases. Of the base‐specific contacts that were observed, contacts to guanine and adenine occurred most frequently. The most favored amino acid–nucleotide pairings observed were lysine–phosphate, tyrosine–uracil, arginine–phosphate, phenylalanine–adenine and tryptophan–guanine. The amino acid propensities showed that positively charged and polar residues were favored as expected, but also so were tryptophan and glycine. The propensities calculated for the functional classes showed trends similar to those observed for the complete data set. However, the analysis of hydrogen bond and van der Waal contacts showed that in general proteins complexed with messenger RNA, transfer RNA and viral RNA have more base specific contacts and less backbone contacts than expected, while proteins complexed with ribosomal RNA have less base‐specific contacts than the expected. Hence, whilst the types of amino acids involved in the interfaces are similar, the distribution of specific contacts is dependent upon the functional class of the RNA bound. Proteins 2007. © 2006 Wiley‐Liss, Inc.
A kampo medicine, Yin‐Chiao‐san, Prevents bleomycin‐induced pulmonary injury in rats
Authors: Yen Feng‐Lin , Wu Tzu‐Hui , Liao Chia‐Wen , Lin Chun‐Ching
Published: December 2006

Yin‐Chiao‐San (YCS), a kampo medicine, is widely used for patients with pulmonary disease and was applied for the treatment of SARS in Asia countries in 2003. For this reason, the present study investigated the preventive effect of YCS on bleomycin (BLM)‐induced pulmonary fibrosis (PF) in rats. Animals were divided into four groups: (1) saline control group; (2) BLM‐induced group, in which 15 mg/kg BLM was intraperitoneally injected three times per week for a period of 5 weeks; (3) BLM + vitamin E (10 mg/kg/day) as a positive group; (4) and BLM + YCS (1000 mg/kg/day). After 35 days, the rats were anesthetized, killed and then the lungs and bronchoalveolar lavage fluids (BALFs) were collected. The attenuation of pulmonary fibrosis was estimated according to the lung index, malondialdehyde (MDA), catalase (CAT), hydroxyproline (HP) and tumor necrosis factor‐α (TNF‐α) level in lung tissue and BALF. The serial sections of lung were stained with haematoxylin‐eosin and Masson trichrome for histopathological observation of pulmonary fibrosis. The results indicated that YCS significantly reduced the lung index, MDA, HP and TNF‐α, but YCS significantly enhanced the CAT level when compared with the BLM‐induced group (p < 0.05). Additionally, the BLM group displayed severe histopathological change in the lung tissue, but YCS treatment could attenuate the BLM‐induced PF. In conclusion, the results demonstrated that YCS possesses antioxidant and antiinflammatory activities and also inhibited collagen formation. Thus, YCS exhibited a preventive effect in BLM‐induced PF and it is suggested that YCS may be applied to attenuate the side effects of BLM in chemotherapy. Copyright © 2006 John Wiley & Sons, Ltd.
In Vitro acetylcholinesterase inhibitory properties of thymol, carvacrol and their derivatives thymoquinone and thymohydroquinone
Authors: Jukic Mila , Politeo Olivera , Maksimovic Milka , Milos Mia , Milos Mladen
Published: December 2006

The aim of this study was to examine in vitro the inhibitory activity exerted by the main constituents of essential oil obtained from the aromatic plant Thymus vulgaris L. on acetylcholinesterase (AChE). The total essential oil and selected compounds, specifically linalool and thymol, carvacrol and their derivatives thymoquinone and thymohydroquinone, were tested for AChE inhibition. Thymohydroquinone exhibited the strongest AChE inhibitory effect over the range of concentrations. The AChE inhibitory potential decreased in the following order: thymohydroquinone > carvacrol > thymoquinone > essential oil > thymol > linalool. It is interesting that the AChE inhibitory effect exerted by carvacrol was 10 times stronger than that exerted by its isomer thymol, although thymol and carvacrol have a very similar structure. Copyright © 2006 John Wiley & Sons, Ltd.
Phytochemical, pharmacological and ethnobotanical studies of Rhazya stricta Decne.
Authors: Gilani Syed Abdullah , Kikuchi Akira , Shinwari Zabta Khan , Khattak Zafar Iqbal , Watanabe Kazuo N.
Published: December 2006

Rhazya stricta Decne. is an important medicinal species that is rich in alkaloids containing anticancer alkaloids also. This paper reviews phytochemical, pharmacological and ethnobotanical studies of R. stricta. Phytochemical and pharmacological aspects of the species have been thoroughly explored. Over 100 alkaloids have been isolated from R. stricta, but the pharmacological activities are known for only a few of these compounds. Very few ethnobotanical studies of R. stricta have been done, and there is a particular need for such studies in various regions of South Asia and in Middle Eastern countries where the species grows. These ethnobotanical studies should investigate herbal recipes of R. stricta and their use for curing diseases. The genetic diversity, chemotaxonomy and allelopathy of R. stricta have not yet been explored, and these studies are recommended, with the ultimate goal of benefiting local communities in regions where R. stricta grows. This should be achieved by sharing knowledge and through the manufacture of herbal drugs from R. stricta's active chemical constituents, while protecting intellectual property rights and following the World Health Organization's guidelines for safety and efficacy. Copyright © 2006 John Wiley & Sons, Ltd.
Kushenflavonoids induce apoptosis in tumor cells by inhibition of NF‐κB activation and multiple receptor tyrosine kinase activities
Authors: Han Jun , Sun Mingyu , Cui Yumin , Wang Tao , Zhang Weihan , Guo Mingchuan , Zhou Yuan , Liu Wei , Zhang Meifang , Duan Jifeng , Xiong Sidong , Yao Minghui , Yan Xiaoqiang
Published: December 2006

In this report, the mechanism of the antitumor activities ofKushenflavonoids (KS‐Fs) were explored. KS‐Fs and kurarinone (Kur), a single flavonoid compound, were able to induce apoptosis of H460 and Eca‐109 cellsin vitroand H460 cellsin vivo. The apoptosis inducing effect was enhanced in the presence of Taxol. In H460 xenograft mice treated with Kur, down‐regulation of Bcl‐2 and up‐regulation of caspase 8 and caspase 3 in tumors were observed by immunohistochemical staining. In addition, KS‐Fs and Kur were able to inhibit TNFα‐induced NF‐κB activation in 293 cells mediated by the decreased IκBαphosphorylation. Further the effects of KS‐Fs and Kur on multiple receptor tyrosine kinase activities were explored. In cell‐based assays, KS‐Fs and Kur inhibited the EGF‐induced EGF receptor phosphorylation in A431 cells and a constitutively activated Her‐2 in MDA‐MB‐453s cells. In enzymatic assays, KS‐Fs and Kur inhibited KDR, but not PDGF BR activities. In A431 xenograft mice treated with Kur, an inhibition of EGF receptor phosphorylation in tumors was observed. These results reveal a novel mechanism by which KS‐Fs induces apoptosis in tumors by acting on multiple cellular targets including the inhibition of NF‐κB activation and multiple receptor tyrosine kinase activities. Copyright © 2006 John Wiley & Sons, Ltd.
Robust observation and identification ofnDOF Lagrangian systems
Authors: Rosas Almeida David I. , Alvarez Joaquín , Fridman Leonid
Published: December 2006

A procedure to design a global exponentially stable, second‐order, sliding‐mode observer fornDOF Lagrangian systems is presented. The observer converges to the system state in spite of the existence of bounded disturbances or parameter uncertainties affecting the system dynamics. The generation of sliding modes permits the identification of disturbances using the equivalent output injection which, under some circumstances, can also be used to identify the system parametersviaa continuous version of the last‐square method. The proposed methodology is illustrated with some numerical examples and experiments. Copyright © 2006 John Wiley & Sons, Ltd.
Adaptive sliding mode control for plants with mismatched perturbations to achieve asymptotical stability
Authors: Chang Yaote , Cheng Chih‐Chiang
Published: December 2006

In this paper an adaptive sliding mode control (ASMC) scheme based on the Lyapunov stability theorem is proposed for a class of multi‐input multi‐output (MIMO) systems with mismatched perturbations to solve robust tracking problems. Adaptive mechanisms are employed in the design of a specific sliding surface function, so that when the dynamics of controlled system enters the sliding surface, the adaptive gains are capable of adapting the upper bounds of mismatched perturbations and the trajectories of tracking errors can achieve the objective of asymptotical stability. Some adaptive mechanisms are also employed in the controller's design, so that the reaching phase can be accomplished in a finite time without the requirement of the information of upper bounds of partial mismatched perturbations. Finally the control scheme is applied to control an AC motor for showing the feasibility of the proposed methodology. Copyright © 2006 John Wiley & Sons, Ltd.
Firm, strategic group, and industry influences on performance
Authors: Short Jeremy C. , Ketchen David J. , Palmer Timothy B. , Hult G. Tomas M.
Published: December 2006

A long‐standing debate has focused on the extent to which different levels of analysis shape firm performance. The strategic group level has been largely excluded from this inquiry, despite evidence that group membership matters. In this study, we use hierarchical linear modeling to simultaneously estimate firm‐, strategic group‐, and industry‐level influences on short‐term and long‐term measures of performance. We assess the three levels' explanatory power using a sample of 1,165 firms in 12 industries with data from a 7‐year period. To enhance comparability to previous research, we also estimate the effects using the variance components and ANOVA methods relied on in past studies. To assess the robustness of strategic group effects, we examine both deductively and inductively defined groups. We found that all three levels are significantly associated with performance. The firm effect is the strongest, while the strategic group effect rivals and for some measures outweighs the industry effect. We also found that the levels have varying effects in relation to different performance measures, suggesting more complex relationships than depicted in previous studies. Copyright © 2007 John Wiley & Sons, Ltd.
The legitimacy of strategic alliances: an institutional perspective
Authors: Dacin M. Tina , Oliver Christine , Roy Jean‐Paul
Published: December 2006

Drawing on an institutional perspective, this paper suggests that strategic alliances serve an important legitimating function for firms and that this role, mediated by alliance governance structure and partner selection preferences, has a significant influence on firm and alliance performance. A theoretical framework is proposed that identifies five types of legitimacy associated with strategic alliances and the specific conditions under which legitimation may be an important outcome of strategic alliances. Propositions are developed to explain when firms are most likely to enter into alliances for legitimacy purposes and how the legitimating role of strategic alliances contributes to firm and alliance performance. The paper concludes with a summary and implications of a legitimacy‐based view of alliances. Copyright © 2007 John Wiley & Sons, Ltd.
SPI agility: How to navigate improvement projects
Authors: Aaen Ivan , Börjesson Anna , Mathiassen Lars
Published: December 2006

In this study, we argue that today's changing business environment calls for agile Software Process Improvement (SPI) practices. The study combines experiences from 18 SPI projects executed from 1998 to 2002 at Ericsson in Gothenburg with insights from SPI and agility theory. We suggest that agile SPI practices are both effective and flexible; they employ adaptive governance mechanisms at the corporate level; and they combine different tactics on the project level. We identify and compare two different tactics for SPI projects. Inspired by procedural thinking, the first tactic, the supertanker, employs process‐push and aims for efficient process development and diffusion. On the basis of adaptive thinking, the second tactic, the motorboat, facilitates practice‐pull and aims for adaptive process development and diffusion. We also discuss how agile SPI practices require understanding of the different types of waters in which the two tactics navigate effectively. Copyright © 2006 John Wiley & Sons, Ltd.
A spiral process model for case studies on software quality monitoring—method and metrics
Authors: Andersson Carina , Runeson Per
Published: December 2006

This article presents a spiral process model for an iterative case study on quality monitoring, conducted in an industrial environment. In a highly iterative project, everything seems to happen at the same time: analysis, design and testing. We propose a spiral process model for case studies, and present a study conducted according to the proposed process. In the study, metrics collected from three software development projects are analysed to investigate which characteristics are stable across projects and feature groups of the product. The contribution of the article is multi‐fold, detailing the case study methodology used with its sub‐goals and procedures. Furthermore, the article presents the metrics collected and the results as such from the case study, which gives insights into a complex development environment and the trends of the retrieved data. The analysed data serve as feedback to the project staff to facilitate identification of software process improvement. The data have also been used for defect prediction. Copyright © 2006 John Wiley & Sons, Ltd.
Smoothness of weak solutions of the Ramberg/Osgood equations on plane domains
Authors: Bildhauer M. , Fuchs M.
Published: December 2006

We discuss the weak form of the Ramberg/Osgood equations (also known as the Norton/Hoff model) on two‐dimensional domains and prove continuity of the stress and the strain tensor. These equations are of great importance since they can be used as an approximation for elastic‐perfectly plastic Hencky materials.
A rationale for cystine supplementation in severe homocystinuria
Authors: Lee P. J. , Briddon A.
Published: December 2006

Previous studies have shown that the thiol redox, as measured by the ratio of free/bound cyst(e)ine in unaffected individuals, remains relatively constant. In severe homocystinuria (HCU) where cyst(e)ine moieties are significantly reduced, this redox is only restored when homocyst(e)ine moieties are also taken into account. This appears to stem from an increase in the free/bound homocyst(e)ine ratio with free homocystine acting as a surrogate for free cystine. We examined these ratios in 47 patients (two with a cobalamin C defect, two with methylenetetrahydrofolate reductase deficiency, 16 with pyridoxine‐responsive HCU and 27 with pyridoxine‐nonresponsive HCU). Comparing free/bound homocyst(e)ine ratios to the total cysteine concentration indicates a relative increase of free homocystine as total cysteine concentrations fall below 170 μmol/L. This provides a rationale and treatment algorithm for cyst(e)ine supplementation in homocystinuria.
Occurrence of Conjugated Linolenic Acids in Purified Soybean Oil
Authors: Kinami Tomohisa , Horii Naoto , Narayan Bhaskar , Arato Shingo , Hosokawa Masashi , Miyashita Kazuo , Negishi Hironori , Ikuina Junichi , Noda Ryuji , Shirasawa Seiichi
Published: December 2006

A high‐performance liquid chromatographic (HPLC) method is described for the determination of conjugated linoleic acids (CLA) and conjugated linolenic acids (CLN). Methyl esters prepared from purified lipid fractions of soybean oil were analyzed using an HPLC system equipped with photodiode‐array detector to detect peaks having maximum absorption around 233 and 275 nm. These peaks were concentrated by AgNO3‐silicic acid column chromatography and reversed‐phase HPLC. The structural analysis, of dimethyloxazoline (DMOX) derivatized methyl esters, using gas chromatography–mass spectrometry (GC–MS) showed the occurrence of 9,11‐ and 10,12‐CLA and 8,10,13‐, 8,10,12‐, and 9,11,13‐CLN. The comparison of these conjugated fatty acids with authentic isomers by HPLC revealed the presence of isomeric mixtures of CLA [cis (c),trans(t) or t,c and t,t] and CLN (c,t,t or t,t,c and t,t,t). Traces of 9,11‐ and 10,12‐CLA (c,t or t,c) were found in crude oil. CLN isomers (8,10,12‐18:3 and 9,11,13‐18:3) were found to be forming during the bleaching phase of soybean oil processing. 8,10,13‐CLN and 9,11‐ and 10,12‐CLA (t,t) were only found in soybean oil after the deodorization step. CLN contents in commercial soybean oil varied from 387 to 1,316 mg/kg oil. A decreased level of bleaching earth and temperature resulted in a reduced CLN content. It is possible that CLN would be derived from the linoleate hydroperoxides formed during the processing and storage of soybean oil.