bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantification of the expression level of integrin receptor αvβ3 in cell lines and MR imaging with antibody‐coated iron oxide particles
Authors: Benedetto Sabrina , Pulito Roberta , Crich Simonetta Geninatti , Tarone Guido , Aime Silvio , Silengo Lorenzo , Hamm Jörg 
Published: September 2006

AbstractTargeted imaging requires site‐specific accumulation of a contrast agent (CA), and the properties of that agent must be selected according to the abundance of the target to obtain a signal above the detection limit of the instrument. However, numerical estimates of receptors per cell are rarely found in the literature. Integrin receptors would be particularly promising targets because of their accessibility from the blood stream and expression on activated neovascular endothelial cells. We systematically estimated the number of integrin receptors of cell lines and primary cells by flow cytometry analysis. Since integrin receptors are heterodimeric molecules, and αv forms complexes with various β subunits, the numbers of αv and β3 subunits are therefore dissimilar. The observed values are 3 · 103–1.4 · 104/cell for αv, and 5.3 · 102–1.1 · 104/cell for β3. Despite the low number of exposed receptors, we show that up to single‐cell MR visualization can be achieved with the use of iron oxide beads complexed with antibodies as CAs. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Micro‐mechanical damage and rough crack closure in cementitious composite materials
Authors: Jefferson A. D. , Bennett T. 
Published: September 2006

AbstractA micro‐mechanics based damage model is presented which uses the solution of an elastic body with penny‐shaped cracks. The major new aspect of the work is the inclusion of a rough crack closure component in the model. The model uses a damage‐surface, described in terms of transformed strain components. Inelastic strain components in each direction are computed by considering the total directional strains on an equivalent band of elastic material and then removing the elastic component. Details of the model implementation in a Mathcad sheet are given. The results from a series of single point simulations are given for uniaxial and biaxial tension and compression stress/strain paths. Each path is computed with the full model and with a damage only version of the model which does not simulate crack closure effects. It is shown that the incorporation of the rough contact component allows the model to reproduce dilatant post‐peak behaviour in compression and to simulate, with reasonable accuracy, the shape of the biaxial strength envelope for cementitious composite materials. Copyright © 2006 John Wiley & Sons, Ltd.
A review of reliable numerical models for three‐dimensional linear parabolic problems
Authors: Faragó I. , Horváth R. 
Published: September 2006

AbstractThe preservation of characteristic qualitative properties of different phenomena is a more and more important requirement in the construction of reliable numerical models. For phenomena that can be mathematically described by linear partial differential equations of parabolic type (such as the heat conduction, the diffusion, the pricing of options, etc.), the most important qualitative properties are: the maximum–minimum principle, the non‐negativity preservation and the maximum norm contractivity. In this paper, we analyse the discrete analogues of the above properties for finite difference and finite element models, and we give a systematic overview of conditions that guarantee the required properties a priori. We have chosen the heat conduction process to illustrate the main concepts, but engineers and scientists involved in scientific computing can easily reformulate the results for other problems too. Copyright © 2006 John Wiley & Sons, Ltd.
Complex variable moving least‐squares method: a meshless approximation technique
Authors: Liew K. M. , Feng Cong , Cheng Yumin , Kitipornchai S. 
Published: September 2006

AbstractBased on the moving least‐squares (MLS) approximation, we propose a new approximation method—the complex variable moving least‐squares (CVMLS) approximation. With the CVMLS approximation, the trial function of a two‐dimensional problem is formed with a one‐dimensional basis function. The number of unknown coefficients in the trial function of the CVMLS approximation is less than in the trial function of the MLS approximation, and we can thus select fewer nodes in the meshless method that is formed from the CVMLS approximation than are required in the meshless method of the MLS approximation with no loss of precision. The meshless method that is derived from the CVMLS approximation also has a greater computational efficiency. From the CVMLS approximation, we propose a new meshless method for two‐dimensional elasticity problems—the complex variable meshless method (CVMM)—and the formulae of the CVMM for two‐dimensional elasticity problems are obtained. Compared with the conventional meshless method, the CVMM has a greater precision and computational efficiency. For the purposes of demonstration, some selected numerical examples are solved using the CVMM. Copyright © 2006 John Wiley & Sons, Ltd.
Origin of magnetosome membrane: Proteomic analysis of magnetosome membrane and comparison with cytoplasmic membrane
Authors: Tanaka Masayoshi , Okamura Yoshiko , Arakaki Atsushi , Tanaka Tsuyoshi , Takeyama Haruko , Matsunaga Tadashi 
Published: September 2006

AbstractProkaryotes are known to have evolved one or more unique organelles. Although several hypotheses have been proposed concerning the biogenesis of these intracellular components, the majority of these proposals remains unclear. Magnetotactic bacteria synthesize intracellular magnetosomes that are enclosed by lipid bilayer membranes. From the identification and characterization of several surface and transmembrane magnetosome proteins, we have postulated that magnetosomes are derived from the cytoplasmic membrane (CM). To confirm this hypothesis, a comparative proteomic analysis of the magnetosome membrane (MM) and CM of the magnetotactic bacterium, Magnetospirillum magneticum AMB‐1, was undertaken. Based on the whole genome sequence of M. magneticum AMB‐1, 78 identified MM proteins were also found to be prevalent in the CM, several of which are related to magnetosome biosynthesis, such as Mms13, which is tightly bound on the magnetite surface. Fatty acid analysis was also conducted, and showed a striking similarity between the CM and MM profiles. These results suggest that the MM is derived from the CM.
Cleaning of raw peptide MS/MS spectra: Improved protein identification following deconvolution of multiply charged peaks, isotope clusters, and removal of background noise
Authors: Mujezinovic Nedim , Raidl Günther , Hutchins James R. A. , Peters Jan‐Michael , Mechtler Karl , Eisenhaber Frank 
Published: September 2006

AbstractThe dominant ions in MS/MS spectra of peptides, which have been fragmented by low‐energy CID, are often b‐, y‐ions and their derivatives resulting from the cleavage of the peptide bonds. However, MS/MS spectra typically contain many more peaks. These can result not only from isotope variants and multiply charged replicates of the peptide fragmentation products but also from unknown fragmentation pathways, sample‐specific or systematic chemical contaminations or from noise generated by the electronic detection system. The presence of this background complicates spectrum interpretation. Besides dramatically prolonged computation time, it can lead to incorrect protein identification, especially in the case of de novo sequencing algorithms. Here, we present an algorithm for detection and transformation of multiply charged peaks into singly charged monoisotopic peaks, removal of heavy isotope replicates, and random noise. A quantitative criterion for the recognition of some noninterpretable spectra has been derived as a byproduct. The approach is based on numerical spectral analysis and signal detection methods. The algorithm has been implemented in a stand‐alone computer program called MS Cleaner that can be obtained from the authors upon request.
A proteomic approach for the characterization of C677T mutation of the human gene methylenetetrahydrofolate reductase
Authors: Greco Marilena , Chiriacò Fernanda , Del Boccio Piero , Tagliaferro Luigi , Acierno Raffaele , Menegazzi Paola , Pinca Eleonora , Pignatelli Francesco , Storelli Carlo , Federici Giorgio , Urbani Andrea , Maffia Michele 
Published: September 2006

AbstractMethylenetetrahydrofolate reductase (MTHFR) catalyzes the conversion of methylenetetrahydrofolate (CH2H4folate) to methyltetrahydrofolate (CH3H4folate). The C677T mutation is a common polymorphism of the human enzyme that leads to the replacement of Ala222Val, thermolability of MTHFR, and mild elevation of plasma homocysteine levels. A mild hyperhomocysteinemia is known to be risk factor for cardiovascular and thrombotic diseases, ischemic stroke, neural tube defects, late on‐set dementia, and pregnancy complications. Human plasma of subjects carrying the C677T mutation in the MTHFR gene has been investigated for their protein pattern in order to identify novel molecular hallmarks. 2‐D analysis of the plasma protein allowed the identification of a specific pattern associated with the TT mutant genotype. Noteworthy, we found one spot shifted to a more basic pI in mutant individuals, and MS identification corresponded to vitamin D‐binding protein (DBP or group component (Gc) globulin). MS/MS peptide sequencing allowed to discriminate different allelic variants in the investigated clinical groups. These data confirmed by molecular genetic analysis highlight the novel association between the C677T MTHFR genotype with the Gc2 polymorphism of the DBP. Moreover, we found a quantitative reduction of Apolipoprotein A‐I in mutant individuals, which was associated, in previous studies by others to an increased cardiovascular risk.
Synthesis and properties of poly(phenylacetylenes) having two polar groups or one cyclic polar group on the phenyl ring
Authors: Kono Toshiki , Sakaguchi Toshikazo , Hu Yanming , Shiotsuki Masashi , Sanda Fumio , Masuda Toshio 
Published: September 2006

AbstractPhenylacetylene (PA) derivatives having two polar groups (ester, 2a–d; amide, 4) or one cyclic polar group (imide, 5a–c) were polymerized using (nbd)Rh+[(η6‐C6H5)B−(C6H5)3] catalyst to afford high molecular weight polymers (∼1 × 106 – 4 × 106). The hydrolysis of ester‐containing poly(PA), poly(2a), provided poly(3,4‐dicarboxyPA) [poly (3)], which could not be obtained directly by the polymerization of the corresponding monomer. The solubility properties of the present polymers were different from those of poly(PA) having no polar group; that is, poly(2a)–poly(2d) dissolved in ethyl acetate and poly(4) dissolved in N,N‐dimethylformamide, while poly(PA) was insoluble in such solvents. Ester‐group‐containing polymers [poly(2a)–poly(2d)] afforded free‐standing membranes by casting from THF solutions. The membrane of poly(2a) showed high carbon dioxide permselectivity against nitrogen (PCO2/PN2 = 62). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5943–5953, 2006
Thermochemically induced binding of methyl orange to polycations containing primary amine groups
Authors: Dragan Ecaterina Stela , Mihai Marcela , Airinei Anton 
Published: September 2006

AbstractThe thermochemical transformation of electrostatically formed complexes of methyl orange (MO) with polycations containing primary amine groups such as ammonium salts afforded new polymers with a high concentration of covalently bound 4‐N,N‐dimethylaminoazobenzene groups in the side chain. Poly(allylamine hydrochloride) and poly(β‐aminoethylene acrylamide hydrochloride) were employed as support polycations for MO. The transformation of sulfonate–ammonium ion pairs into sulfonamide bonds, via heating at an elevated temperature, was supported by the polymer properties before and after the thermal treatment. The polymer structure changes were monitored with elemental analysis, Fourier transform infrared, 1H NMR, and ultraviolet–visible absorption spectroscopy, and thermogravimetric analysis. The spacer length between the backbone and azobenzene structures used as side chains strongly influenced the polymer properties before and after the heat‐induced reaction. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5898–5908, 2006
Computer‐aided navigation for arthroscopic hip surgery using encoder linkages for position tracking
Authors: Monahan Emily , Shimada Kenji 
Published: September 2006

AbstractBackgroundWhile arthroscopic surgery has many advantages over traditional surgery, this minimally invasive technique is not often applied to the hip joint. Two main reasons for this are the complexity of navigating within the joint and the difficulty of correctly placing portal incisions without damaging critical neurovascular structures. This paper proposes a computer‐aided navigation system to address the challenges of arthroscopic hip surgery.MethodsUnlike conventional arthroscopic methods, our system uses a hyper‐redundant encoder linkage to track surgical instruments, thus eliminating the occlusion and distortion problems associated with standard optical and electromagnetic tracking systems. The encoder linkage position information is used to generate a computer display of patient anatomy.ResultsThe tracking error from the encoder linkage was evaluated to be within an acceptable range for this tracking prototype, and the new computer‐aided approach to arthroscopic hip surgery was applied to a prototype system for concept verification.ConclusionThis navigation system for arthroscopic hip surgery can be used as a tool to address the challenges of joint navigation and portal placement in arthroscopic hip surgery by visually supplementing the limiting view from the arthroscope. The introduction of a tracking linkage shows significant potential as an alternative to other tracking systems. Positive feedback about the completed demo system was obtained from surgeons who perform arthroscopic proceduces. Copyright © 2006 John Wiley & Sons, Ltd.
Robotic application in epilepsy surgery
Authors: Eljamel M. S. 
Published: September 2006

AbstractBackgroundEpilepsy surgery is cost‐effective and dependent on patient selection, localization and meticulous technique. We report the use of a new robotic system in this surgery for the first time.MethodsThe brain is imaged for both image guidance and robotic application. The robot uses CT‐visible reflective fiducials. Registration is performed by image‐guided surgery (IGS) system and the robot. The robot is used to insert depth electrodes for intra‐operative epileptic focus localization and to localize the temporal horn.ResultsThis technique was used in three patients; the catheter tip was found in the temporal horn in all cases and saved considerable operating time compared to previous experience.ConclusionIt is therefore feasible to use the robot to localize the temporal horn and place depth electrodes during epilepsy surgery with greater precision and consistency and potential time savings. Copyright © 2006 John Wiley & Sons, Ltd.
State/signal linear time‐invariant systems theory: passive discrete time systems
Authors: Z. Arov Damir , J. Staffans Olof 
Published: September 2006

AbstractThis is a continuation of previous work where we developed a discrete time‐invariant linear state/signal systems theory in a general setting. In this article, the state space is required to be a Hilbert space, as earlier, but the signal space is taken to be a Kreĭn space. The notion of the adjoint of a given state/signal system is introduced and exploited throughout the paper, and in particular, in the definition and the study of passive and conservative state/signal systems, which is the main subject of this paper. It is shown that each fundamental decomposition of the Kreĭn signal space is admissible for a passive state/signal system, meaning that there is a corresponding input/state/output representation of the system, a so‐called scattering representation. The connection between different scattering representations and their scattering matrices (i.e. transfer functions) is explained. We show that every passive state/signal system has a minimal conservative orthogonal dilation and minimal passive orthogonal compressions. Passive signal behaviours are defined, and their passive, conservative, andH‐passive realizations are studied. It is shown that the set of all positive self‐adjoint operatorsH(which need not be bounded or have a bounded inverse) for which a state/signal system Σ isH‐passive coincides with the set of generalized positive solutionsHof the Kalman–Yakubovich–Popov inequality for an arbitrary scattering representation of Σ, and consequently, this set does not depend on the particular representation. Under an extra minimality assumption this set contains a minimal solution which defines the available storage, and a maximal solution which defines the required supply. Copyright © 2006 John Wiley & Sons, Ltd.
Weak formulation of boundary conditions for scalar conservation laws: an application to highway traffic modelling
Authors: S. Strub Issam , M. Bayen Alexandre 
Published: September 2006

AbstractThis article proves the existence and uniqueness of a weak solution to a scalar conservation law on a bounded domain. A weak formulation of the boundary conditions is needed for the problem to be well posed. The existence of the solution results from the convergence of the Godunov scheme. This weak formulation is written explicitly in the context of a strictly concave flux function (relevant for highway traffic). The numerical scheme is then applied to a highway scenario with data from highway Interstate‐80 obtained from the Berkeley Highway Laboratory. Finally, the existence of a minimiser of travel time is obtained, with the corresponding optimal boundary control. Copyright © 2006 John Wiley & Sons, Ltd.
Choice of time scale and its effect on significance of predictors in longitudinal studies
Authors: Pencina Michael J. , Larson Martin G. , D'Agostino Ralph B. 
Published: September 2006

AbstractTime‐to‐event regression is a frequent tool in biomedical research. In clinical trials this time is usually measured from the beginning of the study. The same approach is often adopted in the analysis of longitudinal observational studies. However, in recent years there has appeared literature making a case for the use of the date of birth as a starting point, and thus utilize age as the time‐to‐event. In this paper, we explore different types of age‐scale models and compare them with time‐on‐study models in terms of the estimated regression coefficients they produce. We consider six proportional hazards regression models that differ in the choice of time scale and in the method of adjusting for the years before the study. By considering the estimating equations of these models as well as numerical simulations we conclude that correct adjustment for the age at entry is crucial in reducing bias of the estimated coefficients. The unadjusted age‐scale model is inferior to any of the five other models considered, regardless of their choice of time scale. Additionally, if adjustment for age at entry is made, our analyses show very little to suggest that there exists any practically meaningful difference in the estimated regression coefficients depending on the choice of time scale. These findings are supported by four practical examples from the Framingham Heart Study. Copyright © 2006 John Wiley & Sons, Ltd.
Cross‐over trials inStatistics in Medicine: the first ‘25’ years
Authors: Senn Stephen 
Published: September 2006

AbstractPapers on cross‐over trials that have appeared in the first 25 years ofStatistics in Medicineare reviewed. Papers on bioequivalence are also considered. After a brief statistical summary, individual papers are discussed under seven headings: 1. The two‐stage analysis of AB/BA trials, 2. Baselines, 3. Binary and categorical data, 4. Survival data, 5. Modelling carry‐over, 6. Bioequivalence and 7. Components of variation. Finally, a brief assessment of the importance in this field ofStatistics in Medicineis given. Copyright © 2006 John Wiley & Sons, Ltd.
Multi‐period model for disruptive events in interdependent systems
Authors: Kujawski Edouard 
Published: September 2006

AbstractThis paper develops the Multi‐Period Model for Disruptive Events in Interdependent Systems (MPMDEIS). The analysis is divided into two principal periods: (1) an event period that lasts for the duration of the active perturbation and results in the degradation of the interdependent systems, and (2) a recovery period during which the systems evolves to a new equilibrium. The event period perturbation is modeled as a shock that cascades among the interdependent systems and reduces their production capacity. The state of the systems at the end of the event period is specified by its operational unavailability vector, which is given by the initial perturbation strength vector multiplied by an exponential matrix with the interdependency matrix P as the exponent. The coefficients of P represent the relative contribution of the loss of capacity of one system to the loss of another system as the perturbation propagates from one to the other. The quantification of the shock and interdependencies is critical for the realistic assessment of the inflicted damage and formulating effective defensive strategies against terrorist attacks, natural hazards, and technological failures or accidents. The recovery period depends on the implemented response actions and it can be modeled using a systems dynamics approach. The standard economic input‐output tables are unlikely to be appropriate for the events of interest. However, there are probabilistic risk analysis techniques such as eliciting expert opinions and analytic methods which can be used to reliably assess these data. The MPMDEIS is compared with the Inoperability Input‐Output Model (IIM) and Dynamic Input‐Output Inoperability Model (DIIM) and it is demonstrated to avoid IIM and DIIM assumptions that can lead to significant errors for disruptive events in interdependent systems. © 2006 Wiley Periodicals, Inc. Syst Eng 9: 281– 295, 2006
Prognostic Factors in Periampullary and Pancreatic Tumor Resection in Elderly Patients
Authors: Casadei R. , Zanini N. , Morselli‐Labate A. M. , Calculli L. , Pezzilli R. , Potì O. , Grottola T. , Ricci C. , Minni F. 
Published: September 2006

AbstractBackgroundMore than half of all patients with pancreatic adenocarcinoma are over 70 years of age. Life expectancy for the elderly population is increasing and currently major pancreatic resection provides the only meaningful chance of cure for periampullary and pancreatic tumors. Controversy over what constitutes the correct treatment of these tumors in elderly patients continues to this day. The aim of our study was to determine whether age alone or age plus some prognostic factors constitute contraindications to major pancreatic resections.MethodsBetween 2000 and 2005, data from 88 consecutive patients who had major pancreatic resection for periampullary or pancreatic tumors were entered into a prospective database. Fifty‐three patients under 70 years of age (young patients), and 35 patients 70 years of age or older (elderly patients) were compared with respect to several characteristics and the postoperative course.ResultsPostoperative mortality and morbidity, length of hospital stay, and long‐term survival were similar in the two groups. In the elderly group, the mortality rate was significantly higher in patients with chronic obstructive pulmonary disease (COPD), and the morbidity rate was significantly higher in patients with ASA 3 than in patients with ASA 1–2, in whom a pancreaticoduodenectomy or total pancreatectomy had been performed.ConclusionsAge alone is not a contraindication for major pancreatic resection. In elderly patients a careful evaluation of the co‐morbidities and of the type of surgical procedure is mandatory in order to allow the proper selection of those patients best suited for surgery in specialized centers.