bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generalized circulant Strang‐type preconditioners
Authors: Noschese Silvia , Reichel Lothar 
Published: October 2011

SUMMARYStrang's proposal to use a circulant preconditioner for linear systems of equations with a Hermitian positive definite Toeplitz matrix has given rise to considerable research on circulant preconditioners. This paper presents an {eiφ}‐circulant Strang‐type preconditioner. Copyright © 2011 John Wiley & Sons, Ltd.
Moments of a linear operator, with applications to the trace of the inverse of matrices and the solution of equations
Authors: Brezinski Claude , Fika Paraskevi , Mitrouli Marilena 
Published: October 2011

SUMMARYLet H be a real finite dimensional Hilbert space and A an invertible linear operator on it. In this paper, we are interested in obtaining estimations of Tr(A−1) and of the norm of the error when solving the equation Ax = f ∈ H. These estimates are obtained by extrapolation of the moments of A. Numerical results are given, and applications are discussed. Copyright © 2011 John Wiley & Sons, Ltd.
Space‐angle‐energy multigrid methods for Sn discretizations of the multi‐energetic Boltzmann equation
Authors: Lee B. 
Published: October 2011

SUMMARYIn a recent article, the author presented several improved multiple‐coarsening/semi‐coarsening schemes for Sn discretizations of the Boltzmann transport equation, improved over the original multiple‐coarsening/semi‐coarsening schemes. These improvements were derived from detailed space‐angle descriptions of the near‐nullspace components of the integral equation operator. In this paper, we use the techniques of this article to derive a description of the near‐nullspace components of the multi‐energetic Boltzmann equation, and use this description to develop a space‐angle‐energy multigrid method for this equation. This multigrid method is a scheme for solving a high‐dimensional equation: for spatial 3‐d, the equation is 6‐d; for spatial 2‐d, the equation is 5‐d. This method is more robust and efficient than both the commonly used block Gauss‐Seidel iteration that requires solving mono‐energetic Boltzmann equations, and the improved multiple‐coarsening/semi‐coarsening schemes simultaneously applied to all the energy groups. Numerical experiments applied to multi‐energetic equations with isotropic scattering cross‐sections that simulate Compton‐like scattering and fission, as well as anisotropic scattering cross‐sections, are performed to demonstrate the effectiveness of the new scheme. Copyright © 2011 John Wiley & Sons, Ltd.
Pole assignment for linear and quadratic systems with time‐delay in control
Authors: Li T. , Chu E. K‐W. 
Published: October 2011

SUMMARYWe consider the pole assignment problems for time‐invariant linear and quadratic control systems, with time‐delay in the control. Closed‐loop eigenvectors in X = [x1, x2, ⋯  ] are chosen from their corresponding invariant subspaces, possibly optimizing some robustness measure, and explicit expressions for the feedback matrices are given in terms of X. Condition of the problems is also investigated. Our approach extends the well‐known Kautsky, Nichols, and Van Dooren algorithm. Consequently, the results are similar to those for systems without time‐delay, except for the presence of the ‘secondary’ eigenvalues and the condition of the problems. Simple illustrative numerical examples are given. Copyright © 2011 John Wiley & Sons, Ltd.
Interstitial guidance of cancer invasion
Authors: G. Gritsenko Pavlo , Ilina Olga , Friedl Peter 
Published: October 2011

AbstractCancer cell invasion into healthy tissues develops preferentially along pre‐existing tracks of least resistance, followed by secondary tissue remodelling and destruction. The tissue scaffolds supporting or preventing guidance of invasion vary in structure and molecular composition between organs. In the brain, the guidance is provided by myelinated axons, astrocyte processes, and blood vessels which are used as invasion routes by glioma cells. In the human breast, containing interstitial collagen‐rich connective tissue, disseminating breast cancer cells preferentially invade along bundled collagen fibrils and the surface of adipocytes. In both invasion types, physical guidance prompted by interfaces and space is complemented by molecular guidance. Generic mechanisms shared by most, if not all, tissues include (i) guidance by integrins towards fibrillar interstitial collagen and/or laminins and type IV collagen in basement membranes decorating vessels and adipocytes, and, likely, CD44 engaging with hyaluronan; (ii) haptotactic guidance by chemokines and growth factors; and likely (iii) physical pushing mechanisms. Tissue‐specific, resticted guidance cues include ECM proteins with restricted expression (tenascins, lecticans), cell–cell interfaces, and newly secreted matrix molecules decorating ECM fibres (laminin‐332, thrombospondin‐1, osteopontin, periostin). We here review physical and molecular guidance mechanisms in interstitial tissue and brain parenchyma and explore shared principles and organ‐specific differences, and their implications for experimental model design and therapeutic targeting of tumour cell invasion. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Modeling of a concentrating photovoltaic system for optimum land use
Authors: Kim Yong Sin , Kang Sung‐Mo , Winston Roland 
Published: October 2011

ABSTRACTConcentrating photovoltaic solar power plants using dual‐axis trackers are in increasing demand. In a utility‐scale photovoltaic system, both capacity factor and ground coverage ratio are widely used to characterize systems in view of the land use efficiency. Current system modeling approaches lack accurate location‐specific direct normal irradiance (DNI), miss a reliable electrical model for power optimization and conversion and are inadequate for optimizing the tracker array configuration. In this paper, a comprehensive modeling of a concentrating photovoltaic system is introduced. First, a more accurate estimation of hourly DNI is obtained by considering location‐dependent DNI and air mass changes according to the sun's elevation. Second, mismatch effects of modules are factored in. Third, various power optimization and conversion levels are taken into account for optimization with self‐shading in each module. The tracker array configuration has been optimized to maximize energy harvest by getting a maximum capacity factor for a given ground coverage ratio. Copyright © 2011 John Wiley & Sons, Ltd.
Biological Decontamination Using High and Reduced Pressure Nitrogen Afterglows
Authors: Sarrette Jean‐Philippe , Cousty Sarah , Clement Franck , Canal Cristina , Ricard André 
Published: October 2011

AbstractTypical results quantifying the antibacterial efficiencies of high and reduced pressure nitrogen afterglows are presented, using the same microbiological protocol. In parallel, the diffusion of the nitrogen atoms through different polymer membranes is studied.magnified image
Nasal airflow and thoracoabdominal motion in children using infrared thermographic video processing
Authors: Goldman Luis J. 
Published: October 2011

AbstractThe assessment of apnea and asynchronous breathing requires the application of a facemask connected to a pneumotachograph and inductive transducer bands placed around the chest wall. These contact devices may alter the breathing pattern and are difficult to implement, especially in infants and children. This study validates a contactless image‐processing system that simultaneously retrieves breath‐related thermal variations from nasal, ribcage, and abdomen regions of interest (ROI) from infrared thermographic video recordings of children. Thermographic videos were obtained in 17 supine, spontaneously breathing unsedated children (0.33–13.75 years), including 8 patients with respiratory pathology. Representative thermographic signals were obtained from each ROI on a frame‐by‐frame basis. Cronbach's Alpha reliability coefficient assessed the correlation between control nasal pressure period, the visually scored respiratory rate and the fundamental period in the frequency domain of thermographic signals. A cross‐correlation function calculated the time delay and the phase angle between ribcage and abdomen variability. A Cronbach's Alpha value of 0.976 (0.992–0.944 95% CI) suggests a small‐scale measurement error between thermographic and control periods. The ribcage‐abdomen time delay in children with respiratory disease (−0.42 ± 0.707 sec) significantly differed from healthy children (0.22 ± 0.426 sec, P = 0.0125). This novel system reliably acquired time‐aligned nasal airflow and thoracoabdominal motion estimates without relying on attached sensor performance and detected asynchronous breathing in pediatric patients. Pediatr Pulmonol. 2012; 47:476–486. © 2011 Wiley Periodicals, Inc.
Clinical conditions associated with PCP in children
Authors: Saltzman Rushani W. , Albin Stephanie , Russo Pierre , Sullivan Kathleen E. 
Published: October 2011

AbstractPneumocystis jirovecii is a leading cause of opportunistic infections among the immune compromised. During the 1980s, attention focused on patients with HIV, however, with the advent of anti‐retroviral therapy, we wished to revisit the question of underlying diseases associated with Pneumocystis pneumonia in children. We identified 80 cases from 1986 to 2006 and performed a retrospective chart review to identify clinical characteristics for each of the cases. HIV was the single most common associated underlying condition seen in this cohort, accounting for 39% of the cases overall, however, it was seen in just 15% of the cases since 1998. Transplant recipients and oncology patients together comprised another 39% of the cases, with 9% of cases attributed to primary immune deficiency and another 9% of cases associated with less well‐recognized causes of susceptibility. This study documents the ongoing need for vigilance to diagnose Pneumocystis pneumonia in less well‐recognized clinical scenarios. Pediatr Pulmonol. 2012; 47:510–516. © 2011 Wiley Periodicals, Inc.
Effect of water on resonant Raman spectroscopy of closed single‐walled carbon nanotubes
Authors: Ghandour Ahmad J. , Dunstan David J. , Sapelkin Andrei , Hernandez Ignacio , Halsall Matthew P. , Crowe Iain F. 
Published: October 2011

AbstractTunable Raman excitation spectroscopy with 1.55–1.77 eV laser energies was used to map the second van Hove singularities of semiconducting single‐walled carbon nanotubes ropes in air and immersed in water. The optical transitions are assigned to different (n,m) tubes using a correlation of the diameter and radial breathing mode (RBM) in the Raman spectrum. The resonance energies are blue‐shifted when the tubes are immersed in water and the shift depends on the chiral angle. In addition, the RBM frequencies are also blue‐shifted upon immersion in water.
Tailoring the contact thermal resistance at metal–carbon nanotube interface
Authors: Firkowska Izabela , Boden Andre , Vogt Anna‐Maria , Reich Stephanie 
Published: October 2011

AbstractCopper‐decorated carbon nanotubes (CNTs) were synthesized and used as conductive filler to improve the heat transport capabilities of copper matrix. Thermal properties, i.e., thermal diffusivity and thermal conductivity, of copper composite were measured and compared with those containing pristine and functionalized CNTs. Experimental results revealed that composites enriched with nanohybrids where Cu nanoparticles were covalently bonded to CNTs had thermal conductivity four times higher than those containing the same content of pristine CNTs.magnified image
Evaluation of thermal interface resistance in copper‐CNTs composites by means of the flash method.
One‐step separation of high‐purity (6,5) carbon nanotubes by multicolumn gel chromatography
Authors: Liu Huaping , Tanaka Takeshi , Kataura Hiromichi 
Published: October 2011

AbstractWe investigated the separation of the (6,5) chirality from a commercially available (6,5)‐enriched CoMoCAT single‐wall carbon nanotubes (SWCNTs) by the multicolumn gel chromatography method. Results show that several (6,5) fractions with different purities were sorted across the different gel columns. The metallic SWCNTs were collected as the finally unbound SWCNTs. The highest chirality purity of the (6,5) fractions after one‐step separation was 74.5%, which is much higher than that (∼53.8%) of the (6,5) fraction separated from HiPco SWCNTs which contain a broad chirality distribution. This result indicates that the multicolumn method can highly improve the separation yield and efficiency of a specific (n,m) species if it is present at a high level in the starting material.
Origin of the multiferroicity in Eu0.5Ba0.5TiO3
Authors: Wesselinowa J. M. 
Published: October 2011

AbstractWe have proposed a microscopic model with a biquadratic magnetoelectric coupling between the two ordered parameters taking into account the spin–phonon coupling in order to study different properties of multiferroic Eu0.5Ba0.5TiO3. This magnetoelectric coupling is due to an epitaxial strain which occurs by the replacing of the Eu‐ions with the larger Ba‐ions and vice versa. A Green's function technique allows the calculation of magnetic, electric, and phonon properties which are discussed in dependence of temperature and external fields. The magnetization increases with increasing of the electric field, whereas the phonon energy with the magnetic field. This is an evidence for the magnetoelectric coupling.
Tailoring the growth of L10‐FePt for spintronics applications
Authors: Tahmasebi Taiebeh , Piramanayagam Seidikkurippu N. , Sbiaa Rachid , Tan Hang Khume , Law Randall , Lua Sunny , Chong Tow Chong 
Published: October 2011

AbstractThe effect of seed layers on the magnetic and structural properties of FePt thin films was investigated. For the case of Cr(200) seed layer, no ordered L10‐FePt phase in (001) orientation was observed. The insertion of a thin MgO barrier between the Cr and FePt layers improved the perpendicular magnetization orientation of L10‐FePt by limiting diffusion of Cr into the FePt magnetic layer. Ordered L10‐FePt thin films can be developed on Pd[100] at high substrate temperature with the lattice mismatch of below 1% and therefore low roughness compared to MgO or Cr seed layers. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Molecular dynamics studies of lipid bilayer with gramicidin A: Effects of gramicidin a on membrane structure and hydrophobic match
Authors: Saito Hiroaki , Mizukami Taku , Kawamoto Shuhei , Miyakawa Takeshi , Iwayama Masashi , Takasu Masako , Nagao Hidemi 
Published: October 2011

AbstractThe effects of gramicidin A (GA) peptide on the structure of lipid bilayer were studied by molecular dynamics (MD) simulations in the absence and presence of GA peptide. The hydrophobic match between the GA and surrounding lipid bilayer was investigated by the MD simulations of four kinds of lipid bilayer systems: 1,2‐dilauroyl‐sn‐glycero‐3‐phosphatidylcholine (diC12:0‐PC), 1,2‐dimyristoyl‐sn‐glycero‐3‐phosphatidylcholine (DMPC, diC14:0‐PC), 1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphatidylcholine (diC16:0‐PC), and 1,2‐distearoyl‐sn‐glycero‐3‐phosphatidylcholine (DSPC, di18:0‐PC). The observed hydrophobic thickness and order parameter increases, and the gauche conformation decreases in the presence of GA, being consistent with the experimental observations. The acyl chain structure of the DSPC membrane was sufficiently changed to match the length of GA peptide, resulting in a distortion of the membrane surface around the GA peptide. On the other hand, the minor structural changes of lipid and the small fluctuation of the GA were shown in the DMPC membrane. These results indicate that DMPC bilayer has a better hydrophobic match with the GA peptide than the other membranes. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Physicochemical properties of starches obtained from Polish potato cultivars
Authors: Pycia Karolina , Juszczak Lesław , Gałkowska Dorota , Witczak Mariusz 
Published: October 2011

AbstractSelected physicochemical, thermal, and rheological properties of starches isolated from new Polish potato varieties were determined. The starches contained 25.7–30.0 g/100 g d.m. of amylose and 59.5–90.2 mg/100 g d.m. of phosphorus. Gelatinization temperatures were 62.6–64.0, 68.9–69.9, and 73.6–77.0°C for TO, TP, and TE, respectively, whilst enthalpy of gelatinization amounted to 11.1–15.3 J/g. The retrogradation degree of starch was from 52.90 to 78.53%. Pasting curves showed significant differences between the starches. Peak viscosity and final viscosity ranges were 2035–4458 and 1931–2985 mPa · s, respectively. Starch pastes exhibited non‐Newtonian, shear thinning, and thixotropic behavior. After cooling they demonstrated diversified viscoelastic properties, however, all of them were classified as weak gels. Significant linear correlations among selected rheological parameters and amylose and phosphorus content were found. Results of principal component analysis demonstrated an ability to differentiate the starches isolated from different potato varieties.
In situ kinetic study of solid‐state crosslinking of potato starch
Authors: Wang Gang , Thompson Michael R. , Liu Qiang 
Published: October 2011

AbstractThis work studies the solid‐state modification of potato starch using sodium trimetaphosphate (STMP) at elevated temperature (120°C). Kinetics for the reaction was investigated using an in situ technique based on attenuated total reflectance infrared spectroscopy for monitoring the extent of crosslinking. For tested STMP concentrations between 1.6 and 20% (w/w, dry starch basis), the degree of substitution varied between 0.015 and 0.106 mol P/mol anhydroglucose unit, respectively, within a reaction time of less than 10 min. The reaction data was found to follow a first‐order rate dependency and by examination using a phase‐boundary kinetic model was considered to be exterior diffusion limited. The extent of conversion always converged to an asymptotic value less than 100%. The inclusion of 1–2% hydrocolloidal xanthan gum were found to have no effect on the crosslinking of starch whereas 10–30% glycerol significantly lowered the rate of reaction.
Absent mandibular gap in the retronasal triangle view: a clue to the diagnosis of micrognathia in the first trimester
Authors: Sepulveda W. , Wong A. E. , Viñals F. , Andreeva E. , Adzehova N. , Martinez‐Ten P. 
Published: October 2011

AbstractObjectiveTo describe a new ultrasound technique that may be useful for the diagnosis of micrognathia in the first trimester of pregnancy.MethodsThe retronasal triangle (RNT) view is a technique that captures the coronal plane of the face in which the primary palate and the frontal processes of the maxilla are visualized simultaneously. Normal first‐trimester fetuses display a characteristic gap between the right and left body of the mandible in this view (the ‘mandibular gap’). The presence or absence of this gap was evaluated and measured prospectively during real‐time scanning (n = 154) and retrospectively by analyzing three‐dimensional (3D) datasets (n = 50) in normal first‐trimester fetuses undergoing screening for aneuploidy at 11–13 weeks' gestation. 3D datasets from 12 fetuses with suspected micrognathia were also collected and examined retrospectively for the same features.ResultsThe mandibular gap was identified in all 204 normal fetuses and increased linearly with increasing crown–rump length (y = 0.033x + 0.435; R2 = 0.316), with no statistically significant differences between measurements obtained by two‐dimensional ultrasound and 3D offline analysis. Among fetuses with suspected micrognathia, three 3D datasets were excluded from analysis because of poor image quality in one and the diagnosis of a normal chin in two. In the remaining nine fetuses, the mandibular gap was absent and was replaced by a bony structure representing the receding chin in seven (77.8%) cases and was not visualized due to severe retrognathia in the remaining two (22.2%) cases. All fetuses with micrognathia had associated anomalies, including seven with aneuploidy and two with skeletal dysplasia.ConclusionsThe RNT view may be a helpful technique for detecting micrognathia in the first trimester. The absence of the mandibular gap or failure to identify the mandible in this view is highly suggestive of micrognathia and should prompt a targeted ultrasound scan to assess for other anomalies. Further research is needed to determine the false‐positive and false‐negative rates of this technique. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.
The Front‐end Desaturase: Structure, Function, Evolution and Biotechnological Use
Authors: Meesapyodsuk Dauenpen , Qiu Xiao 
Published: October 2011

AbstractVery long chain polyunsaturated fatty acids such as arachidonic acid (ARA, 20:4n‐6), eicosapentaenoic acid (EPA, 20:5n‐3), docosapentaenoic acid (DPA, 22:5n‐3) and docosahexaenoic acid (DHA, 22:6n‐3) are essential components of cell membranes, and are precursors for a group of hormone‐like bioactive compounds (eicosanoids and docosanoids) involved in regulation of various physiological activities in animals and humans. The biosynthesis of these fatty acids involves an alternating process of fatty acid desaturation and elongation. The desaturation is catalyzed by a unique class of oxygenases called front‐end desaturases that introduce double bonds between the pre‐existing double bond and the carboxyl end of polyunsaturated fatty acids. The first gene encoding a front‐end desaturase was cloned in 1993 from cyanobacteria. Since then, front‐end desaturases have been identified and characterized from a wide range of eukaryotic species including algae, protozoa, fungi, plants and animals including humans. Unlike front‐end desaturases from bacteria, those from eukaryotes are structurally characterized by the presence of an N‐terminal cytochrome b5‐like domain fused to the main desaturation domain. Understanding the structure, function and evolution of front‐end desaturases, as well as their roles in the biosynthesis of very long chain polyunsaturated fatty acids offers the opportunity to engineer production of these fatty acids in transgenic oilseed plants for nutraceutical markets.
Survey of anaemia andHelicobacter pyloriinfection in adolescent girls in Suihua, China and enhancement of iron intervention effects byH. pylorieradication
Authors: Xia Wei , Zhang Xin , Wang Jiajia , Sun Caihong , Wu Lijie 
Published: October 2011

In the present study, we investigated the prevalence of anaemia and Fe deficiency anaemia (IDA) and explored the relationship betweenHelicobacter pyloriinfection and IDA in adolescent girls. A total of 1037 adolescent girls from Suihua, China were enrolled. Hb, serum ferritin (SF), serum transferrin receptor (sTfR) and serum IgG antibodies toH. pyloriwere measured. Participants with IDA and co-existingH. pyloriinfection (n80) who had an intake of >25 mg/d of Fe were assigned randomly to the intervention and control groups. Patients in the intervention group were administered a 12-week course of oral EDTA–Na–Fe (60 mg Fe/dose, three times a week) and a 2-week course of colloidal bismuth subcitrate, amoxicillin and metronidazole. Subjects in the control group were administered EDTA–Na–Fe alone. Hb, SF and sTfR were reassessed 3 months after the 12-week regimen ended. Prevalence of anaemia, Fe deficiency (defined as SF < 12·0 μg/l), IDA andH. pyloriinfection in the population of 1037 was 19·5, 40·4, 17·1 and 31·2 %, respectively. The prevalence ofH. pyloriinfection in the IDA group was 46·9 %, while the non-anaemic group had 28·1 % prevalence. A significant increase in Hb and SF and a decrease in sTfR value were found in the intervention group and theH. pylori-negative group. Findings suggest that IDA is still one of the prominent problems in adolescent girls. There is an association betweenH. pyloriinfection and IDA. Treatment ofH. pyloriinfection is associated with a more rapid response to oral Fe therapy.