bluuebunny/crossref_metadata_2025_split huggingface dataset:
Homocysteine levels and disease duration independently correlate with coronary artery calcification in patients with systemic lupus erythematosus
Authors: Von Feldt Joan M. , Scalzi Lisabeth V. , Cucchiara Andrew J. , Morthala Suneetha , Kealey Carmel , Flagg Stephanie D. , Genin Anna , Van Dyke Alison L. , Nackos Eleni , Chander Avantika , Gehrie Erika , Cron Randy Q. , Whitehead Alexander S. 
Published: June 2006

AbstractObjectiveTo compare the incidence and extent of coronary artery calcification (CAC) as measured by electron beam computed tomography (EBCT) in patients with systemic lupus erythematosus (SLE) and controls, and to identify variables associated with CAC in patients with SLE.MethodsFemale patients with SLE and matched controls were recruited; EBCT of the coronary arteries was performed, and laboratory values (including the homocysteine concentration, the lipid level, the high‐sensitivity C‐reactive protein [hsCRP] concentration, the glomerular filtration rate [GFR], and the level of soluble CD154 [sCD154]) were determined. For patients, the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index and the SLE Disease Activity Index scores were recorded. Tests of association between the CAC score and the above‐mentioned variables were performed.ResultsThe incidence of CAC was higher in patients with SLE than in controls (P = 0.009), and patients had a higher mean raw CAC (rCAC) score (87.9 versus 9.6 in controls; P = 0.02). In particular, more CAC‐positive patients than CAC‐positive controls had rCAC scores above the 75th percentile (P = 0.003). Among both patients and controls, those with CAC were ∼10 years older than those without CAC. In addition to age, a significant determinant of positive CAC status in both groups was the number of cardiovascular risk factors. In patients with SLE, CAC was associated with a higher homocysteine concentration, a lower GFR, and longer disease duration. In controls, the total cholesterol level correlated positively with CAC. When multivariate logistic regression methods were applied to candidate explanatory variables, homocysteine concentration, age, and disease duration (but not the levels of sCD154 or hsCRP) contributed significantly to CAC status. The methylenetetrahydrofolate reductase C677T genotype was not a predictor of hyperhomocysteinemia or CAC status.ConclusionAmong patients with SLE, the homocysteine concentration, the GFR, age, and disease duration were associated with CAC. CAC occurred more frequently and was more extensive in patients with SLE than in controls, suggesting that EBCT could be used to detect premature atherosclerosis in the former group. An elevated homocysteine concentration might identify patients with SLE who are likely to have premature atherosclerosis and who would benefit from evaluation of CAC by EBCT.
Anti‐20S proteasome autoantibodies inhibit proteasome stimulation by proteasome activator PA28
Authors: Brychcy Michael , Kuckelkorn Ulrike , Hausdorf Gert , Egerer Karl , Kloetzel Peter‐M. , Burmester Gerd‐R. , Feist Eugen 
Published: June 2006

AbstractObjectiveThe ubiquitin‐proteasome system plays a central role in cellular homeostasis as well as in regulation of the inflammatory and stress responses. However, the occurrence of autoantibodies against 20S proteasome has, to date, been considered to be a nonspecific epiphenomenon in patients with autoimmune disorders. This study was undertaken to analyze the properties of antiproteasome antibodies by investigating their influence on the proteolytic activity of the proteasome complex.MethodsThe 20S proteasome, with or without addition of the proteasome activator (PA28), was preincubated with affinity‐purified human antiproteasome antibodies. Proteolytic activity was estimated using fluorogenic peptides as substrate.ResultsThe baseline proteolytic properties of the 20S proteasome core complex were not influenced by the autoantibodies in vitro. In contrast, all human antiproteasome antibodies analyzed efficiently blocked the enhanced proteasomal substrate cleavage provided by PA28. A similar influence of proteasome activation was observed upon preincubation with affinity‐purified sheep polyclonal or mouse monoclonal antiproteasome antibody, whereas human immunoglobulin controls exhibited no effect.ConclusionAutoantibodies against 20S proteasomes are able to block proteasome activation by PA28, binding to their native antigen in vitro. Antibody targeting of the interaction between 20S proteasome and PA28 represents a novel mechanism of proteasome inhibition.
Solvent‐induced lysozyme gels: Effects of system composition and temperature on structural and dynamic characteristics
Authors: da Silva Marcelo A. , Farhat Imad A. , Arêas Elizabeth P. G. , Mitchell John R. 
Published: June 2006

AbstractThe gelation process of lysozyme in water/tetramethylurea in the presence of salt was investigated as a function of temperature and system composition by rheology, infrared spectroscopy, and microcalorimetry. Times and temperatures of gelation were determined from the variation of the storage (G′) and loss (G′′) moduli. It was found that gelation times follow exponential decays with both protein and tetramethylurea (TMU) concentrations and with temperature. The activation energy for the overall process shows a linear dependence on TMU mass fraction. A strongly increased β‐sheet content and reduced α‐helix occur with the increase of TMU concentration in the binary solvent. Also, a linear decrease of lysozyme denaturation temperature and enthalpy on TMU concentration is found for the TMU mass fraction up to 0.5, above which no denaturation signal can be detected. © 2006 Wiley Periodicals, Inc. Biopolymers 83: 443–454, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Quantification of astaxanthin in shrimp waste hydrolysate by HPLC
Authors: López‐Cervantes J. , Sánchez‐Machado D. I. , Gutiérrez‐Coronado M. A. , Ríos‐Vázquez N. J. 
Published: June 2006

AbstractIn the present study, a simple and rapid reversed‐phase HPLC method for the determination of astaxanthin in shrimp waste hydrolysate has been developed and validated. The analytical procedure involves the direct extraction of astaxanthin from the lipid fraction with methanol. The analytical column, SS Exil ODS, was operated at 25C. The mobile phase consisted of a mixture of water:methanol:dichloromethane:acetonitrile (4.5:28:22:45.5 v/v/v/v) at a flow rate of 1.0 mL/min. Detection and identification were performed using a photodiode array detector (λdetection = 476 nm). The proposed HPLC method showed adequate linearity, repeatability and accuracy. Copyright © 2006 John Wiley & Sons, Ltd.
Photoinduced Electron Transfer in α‐Cyclodextrin‐Based Supramolecular Dyads: A Free‐Energy‐Dependence Study
Authors: Balan Bijitha , Gopidas Karical R. 
Published: June 2006

AbstractPhotoinduced electron transfer (PET) between α‐cyclodextrin‐appended pyrene (PYCD) and a few acceptor molecules was studied in aqueous solutions. The pyrene moiety in PYCD is located above the narrower rim of the α‐CD and is fully exposed to water. The acceptors are monocyclic organic molecules and, upon dissolution in water in the presence of PYCD, a fraction of the donor–acceptor systems is present as supramolecular dyads and the remaining fraction as free molecules. Free‐energy‐dependence studies showed that electron transfer in the supramolecular dyads follows the Marcus equation. The donor–acceptor coupling and the reorganization energy were determined from fits of the data to the Marcus equation. The electronic coupling was found to be similar to those reported for hydrogen‐bonded systems. It appears that the actual λout values are somewhat lower than values calculated with the continuum model. The experimental design has also allowed, for the first time, a visual demonstration of the inverted region on the basis of the raw fluorescence lifetime data.
Assembly‐Controlled Biocompatible Interface on a Microchip: Strategy to Highly Efficient Proteolysis
Authors: Liu Yun , Zhong Wei , Meng Sheng , Kong Jilie , Lu Haojie , Yang Pengyuan , Girault Hubert H. , Liu Baohong 
Published: June 2006

AbstractA biocompatible interface was constructed on a microchip by using the layer‐by‐layer (LBL) assembly of charged polysaccharides incorporating proteases for highly efficient proteolysis. The controlled assembly of natural polyelectrolytes and the enzyme‐adsorption step were monitored by using a quartz‐crystal microbalance and atomic force microscopy (AFM). Such a multilayer‐assembled membrane provides a biocompatible interconnected network with high enzyme‐loading capacity. The maximum digestion rate of the adsorbed trypsin in a microchannel was significantly accelerated to 1600 mM min−1 μg−1, compared with the tryptic digestion in solution. Based on the Langmuir isotherm model, the thermodynamic constant of adsorption K was calculated to be 1.6×105 M−1 and the maximum adsorption loading Γmax was 3.6×10−6 mol m−2, 30 times more than a monolayer of trypsin on the native surface. The tunable interface containing trypsin was employed to construct a microchip reactor for digestion of femtomoles of proteins and the produced peptides were analyzed by MALDI‐TOF mass spectroscopy. The efficient on‐chip proteolysis was obtained within a few seconds, and the identification of biological samples was feasible.
Flexibility of Inorganic Tennis Ball Structures Inducing Anion Selectivity
Authors: Kim Ki‐Hyun , Park Jung Su , Kang Tae Yi , Oh Kyungeun , Seo Mi‐Sook , Sohn Youn Soo , Jun Moo‐Jin , Nam Wonwoo , Kim Kwan Mook 
Published: June 2006

AbstractInorganic tennis balls (ITBs), [[{Pt(betmp)(dach)}2Cu]2(X)][X]3 (in which X=ClO4− (3), NO3− (4), Cl− (5) and Br− (6); dach=trans‐1,2‐diaminocyclohexane and betmp=bisethylthiomethylidenepropanedioate) and [[{Pt(dteym)(dach)}2Cu]2(PF6)][PF6]3 (7; dteym=1,3‐dithiepane‐2‐ylidenemalonate), were prepared as crystals. Investigation of their X‐ray crystal structures revealed that shapes of the cavities in ITBs show significant distortions that depend on the properties of the encapsulated anions. The Cu⋅⋅⋅Cu* distance was observed to be longest in 7 and shortest in 5, the difference between them being 2.05 Å. The flexibility of cavity structures of ITBs makes it possible to encapsulate various anions inside the cavity, while their distortions may be a reason for the difference in the encapsulating ability for anions, that is, anion selectivity. Especially, the distortions observed in 7 are so severe that the encapsulating ability of the cavity for PF6− is very low compared to other anions. The shapes of ITBs with ClO4− and BF4− ions inside their cavities are very similar; however, ClO4− is encapsulated by the cavity better than BF4−, which is explicable by the difference of metal–anion interactions. This structural study on ITBs gives a clue to the origin of the anion selectivity of the cavity in ITBs previously investigated by 19F NMR spectroscopy of the ITBs in methanol.
o‐DPPB‐Directed Copper‐Mediated and ‐Catalyzed Allylic Substitution with Grignard Reagents
Authors: Demel Peter , Keller Manfred , Breit Bernhard 
Published: June 2006

AbstractThe ortho‐diphenylphosphanylbenzoyl (o‐DPPB) group was explored as a directing leaving group in copper‐mediated and copper‐catalyzed allylic substitution with Grignard reagents. Complete control of chemo‐, regio‐ and stereoselectivity with complete syn‐1,3‐chirality transfer was observed as a result of the directed nature of the reaction. No excess of organometallic reagent is required and the directing group can be recovered quantitatively. Coordination studies in the solid state and in solution have shown that two substrates are bound via the phosphine function of the directing group at copper. Dynamic NMR experiments in solution are in agreement with a ligand‐exchange process at copper, a prerequisite for the development of a substoichiometric process.
S‐Thiazolinyl (STaz) Glycosides as Versatile Building Blocks for Convergent Selective, Chemoselective, and Orthogonal Oligosaccharide Synthesis
Authors: Pornsuriyasak Papapida , Demchenko Alexei V. 
Published: June 2006

AbstractIn the aim of developing new procedures for efficient oligosaccharide assembly, a range of S‐thiazolinyl (STaz) glycosides have been synthesized. These novel derivatives were evaluated against a variety of reaction conditions and were shown to be capable of being chemoselectively activated in the armed–disarmed fashion. Moreover, the S‐thiazolinyl moiety exhibited a remarkable propensity for selective activation over other common leaving groups. Conversely, a variety of leaving groups could be selectively activated over the STaz moiety, which, in turn, allowed STaz/S‐ethyl and STaz/S‐phenyl orthogonal approaches. To demonstrate versatility of novel STaz derivatives, a number of oligosaccharide targets have been synthesized in a convergent selective, orthogonal, and chemoselective fashion.
Regio‐ and Stereoselective Palladium‐Pincer Complex Catalyzed Allylation of Sulfonylimines with Trifluoro(allyl)borates and Allylstannanes: A Combined Experimental and Theoretical Study
Authors: Wallner Olov A. , Szabó Kálmán J. 
Published: June 2006

AbstractRegio‐ and stereoselective palladium‐pincer complex catalyzed allylation of sulfonylimines has been performed by using substituted trifluoro(allyl)borates and trimethylallylstannanes. The reactions provide the corresponding branched allylic products with excellent regioselectivity. The stereoselectivity of these processes is very high when trifluoro(cinnamyl)borate and trimethyl cinnamyl stannane are employed as allylic precursors; however, the reaction with trifluoro(crotyl)borate results in poor stereoselectivity. The major diastereomer formed in these reactions was the syn isomer, while the (previously reported) reactions with aldehyde electrophiles afforded the anti products, indicating that the mechanism of the stereoselection is dependent on the applied electrophile. Therefore, we have studied the mechanistic aspects of the allylation reactions by experimental studies and DFT modeling. The experimental mechanistic studies have clearly shown that potassium trifluoro(allyl)borate undergoes transmetallation with palladium‐pincer complex 1 a affording an η1‐allylpalladium‐pincer complex (1 e). The mechanism of the transfer of the allyl moiety from palladium to the sulfonylimine substrate was studied by DFT calculations at the B3PW91/LANL2DZ+P level of theory. These calculations have shown that the electrophilic substitution of sulfonylimines proceeds in a one‐step process with a relatively low activation energy. The topology of the potential energy surface in the vicinity of the transition‐state structure proved to be rather complicated as nine different geometries with similar energies were located as first order saddle points. Our studies have also shown that the high stereoselectivity with cinnamyl metal reagents stems from steric interactions in the TS structure of the allylation reaction. In addition, these studies have revealed that the mechanism of the stereoselection in the allylation of aldehydes and sulfonylimines is fundamentally different.
Deep Blue Mixed‐Valent PtIIIPtIIIPtII Complex [Pt3Br2(μ‐pz)6] (pz=Pyrazolate) Showing Valence‐Detrapping Behavior in Solution
Authors: Umakoshi Keisuke , Kojima Takashi , Kim Yong Hun , Onishi Masayoshi , Nakao Yoshihide , Sakaki Shigeyoshi 
Published: June 2006

AbstractThe oxidation of the pyrazolate bridged cyclic PtII trimer, [Pt3(μ‐pz)6] (1), in the presence of bromide ion gave a deep blue mixed‐valent PtII,III,III complex, [Pt3Br2(μ‐pz)6] (2). The structural analysis of 2 disclosed that the complex has localized PtPt bond. Our theoretical calculations revealed that the HOMO and LUMO of Pt3II,III,III species mainly consists of (dσ–dσ) and (dσ–dσ)* orbitals, respectively, and the origin of deep blue color of the bromo complex, 2, arises from the (dσ–dσ)→(dσ–dσ)* transition. Unique fluxional behavior was observed due to valence‐detrapping of 2 in solution. The activation parameters of the valence‐detrapping of 2 obtained by Eyring analyses were ΔH≠=37(2) kJ mol−1 and ΔS≠=−67(7) J mol−1 K−1.
Influence of obesity on biochemical and clinical failure after external‐beam radiotherapy for localized prostate cancer
Authors: Strom Sara S. , Kamat Ashish M. , Gruschkus Stephen K. , Gu Yun , Wen Sijin , Cheung Min Rex , Pisters Louis L. , Lee Andrew K. , Rosser Charles J. , Kuban Deborah A. 
Published: June 2006

AbstractBACKGROUND.Several reports have shown that obesity is associated with increased risk of biochemical failure after radical prostatectomy. However, limited information is available regarding the impact of obesity on prostate cancer progression after radiotherapy. The current study sought to determine whether obesity was an independent predictor of biochemical failure (BF) and clinical recurrence (CF) among patients treated with external‐beam radiotherapy (EBRT).METHODS.A retrospective analysis was performed on 873 patients receiving EBRT as the sole treatment for localized prostate cancer between 1988 and 2001. The Kaplan–Meier method, log‐rank test, and Cox proportional hazards analyses were performed.RESULTS.Of the 873 patients, 18% were mildly obese and 5% were moderately to severely obese. Obesity was related to younger age at diagnosis (P < .001), more recent year of diagnosis (P = .03), and race (P = .03), with African‐American men having the highest obesity rates. During a mean follow‐up of 96 months, 295 patients experienced BF and 127 had CF. On multivariate analysis, controlling for clinical and treatment characteristics, increased body mass index (BMI) significantly predicted BF (hazards ratio [HR] = 1.04; 95% confidence interval [95% CI], 1.02–1.07) with a positive trend by BMI category (P = .001). Similar results were found when the outcome was CF; BMI remained an independent predictor of progression (HR = 1.05; 95% CI, 1.01–1.09), with a statistically significant trend by increased BMI category (P = .03).CONCLUSIONS.The current findings validate the important role of obesity, not only on BF but also on CF, and suggest a link to the biologic basis of tumor progression that can be therapeutically exploited. Cancer 2006. © 2006 American Cancer Society.
Object comparison using PDE‐based wave metric on cellular neural networks
Authors: Szatmári István 
Published: June 2006

AbstractThe paper investigates PDE‐based dynamic phenomena for comparing objects and introduces a spatio‐temporal non‐linear wave metric. This metric is capable of comparing both binary and grey‐scale object pairs in a parallel way. Spatio‐temporal waves are initialized and controlled to explore the quantitative properties of objects. In addition to spatial data, even ‘hidden’, time‐related information is also extracted and used for evaluating differences and similarities. The detailed analysis of the proposed metric shows that this wave‐based approach can outperform well‐known metrics such as Hausdorff and Hamming metrics in selectivity and sensitivity. The approach in question can be efficiently implemented on massively parallel architectures, e.g. on Cellular Neural/Non‐linear Networks (CNN), providing solutions either for real time applications. Copyright © 2006 John Wiley & Sons, Ltd.
Computational auditory scene analysis in cellular wave computing framework
Authors: Fodróczi Zoltán , Radványi András 
Published: June 2006

AbstractExtracting substantive auditory objects from an auditory mixture is a widely studied and difficult problem in auditory research. Computational auditory scene analysis (CASA) aims at extracting objects in the frequency domain, based on a set of psychoacoustic grouping procedures. To mimic some aspects of the human auditory system a new cellular neural/non‐linear network (CNN)‐based library of procedures forming an Auditory Wave Computing Toolkit (AWCT) is presented here. Copyright © 2006 John Wiley & Sons, Ltd.
Emulated digital CNN‐UM solution of partial differential equations
Authors: Nagy Zoltán , Vörösházi Zsolt , Szolgay Péter 
Published: June 2006

AbstractWe present here new cellular neural/non‐linear networks (CNN)‐based emulated digital architectures specifically designed for the solution of different partial differential equations (PDE). The array structure and local connectivity of the CNN paradigm make it a natural framework to describe the behaviour of locally interconnected dynamical systems. Solution of the PDE is carried out by a spatio‐temporal dynamics, which can be computed in real‐time on analogue CNN‐UM chips, but the accuracy of the solution is low. Additionally, solution of PDEs on a CNN‐UM architecture often requires a multi‐layer structure and non‐linear templates which is partially or not supported on the current analogue VLSI CNN‐UM chips. To overcome these obstacles while preserving high computing performance a configurable emulated digital CNN‐UM can be used where the main parameters (accuracy, template size and number of layers) are configurable. Additionally, the symmetry of the finite difference operators makes it possible to specialize the emulated digital CNN‐UM architecture to solve a specific type of PDE, which results in higher performance. Emulated digital CNN‐UM processors use fixed‐point numbers to carry out computations, and by decreasing the precision the speed of the computations can be improved. Hence, a simple algorithm is introduced to determine the optimal fixed‐point precision and maximize computing performance. Copyright © 2006 John Wiley & Sons, Ltd.
3D tactile sensor array processed by CNN‐UM: a fast method for detecting and identifying slippage and twisting motion
Authors: Kis Attila , Kovács Ferenc , Szolgay Péter 
Published: June 2006

AbstractIn this paper, we present a fast and efficient technique for detecting and identifying the slippage and twisting motion of touching objects. This kind of action cannot be detected with tactile sensors sensing only the normal (perpendicular) component of the forces acting between surfaces. Our approach utilizes an integrated sensing–processing–actuating system comprising: (1) A 2 × 2 taxel (tactile pixel) array mounted on a two‐fingered robot hand, (2) a 64 × 64 CNN‐UM (Cellular Neural Network‐Universal machine), and (3) a closed‐loop controller. This arrangement, along with the proper analogic algorithm, allows detection and the control of the tactile event. It is essential to know and comprehend the forces between contact surfaces and the related 3D pressure fields is essential in many robotic applications discussed in the paper. Copyright © 2006 John Wiley & Sons, Ltd.
Dense CMOS implementation of a binary‐programmable cellular neural network
Authors: Flak Jacek , Laiho Mika , Paasio Ari , Halonen Kari 
Published: June 2006

AbstractAn implementation of a cellular neural/non‐linear network (CNN) for processing black‐and‐white (B/W) images is presented in which the template terms are 1‐bit programmable. Such approach leads to a very compact implementation of the coefficient circuits and fast (digital) programming. In this programming scheme, the more complex templates are split into subtasks that are run successively. The structure allows a direct or algorithmic evaluation of the majority of templates proposed for B/W images. The transient mask is utilized in performing the local logic operations as well as in template operations. The proposed architecture is suitable for high‐density implementations. A test structure of a 4 × 4 network has been implemented with a standard digital 0.18‐µm CMOS process. One cell occupies only 155 µm2, making possible the implementations of very large networks on a single chip. The algorithms used for the logic function computations and selected template evaluations are described, and the corresponding measurement results are shown. Copyright © 2006 John Wiley & Sons, Ltd.