bluuebunny/crossref_metadata_2025_split huggingface dataset:
Survey of sparse and non‐sparse methods in source separation
Authors: O'Grady Paul D. , Pearlmutter Barak A. , Rickard Scott T. 
Published: July 2005

AbstractSource separation arises in a variety of signal processing applications, ranging from speech processing to medical image analysis. The separation of a superposition of multiple signals is accomplished by taking into account the structure of the mixing process and by making assumptions about the sources. When the information about the mixing process and sources is limited, the problem is called ‘blind’. By assuming that the sources can be represented sparsely in a given basis, recent research has demonstrated that solutions to previously problematic blind source separation problems can be obtained. In some cases, solutions are possible to problems intractable by previous non‐sparse methods. Indeed, sparse methods provide a powerful approach to the separation of linear mixtures of independent data. This paper surveys the recent arrival of sparse blind source separation methods and the previously existing non‐sparse methods, providing insights and appropriate hooks into theliterature along the way. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15;18–33;2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20035
Variational blind deconvolution of multi‐channel images
Authors: Kaftory Ran , Sochen Nir , Zeevi Yehushua Y. 
Published: July 2005

AbstractThe fundamental problem of denoising and deblurring images is addressed in this study. The great difficulty in this task is due to the ill‐posedness of the problem. We analyze multi‐channel images to gain robustness and regularize the process by the Polyakov action, which provides an anisotropic smoothing term that uses inter‐channel information. Blind deconvolution is then solved by an additional anisotropic regularization term of the same type for the kernel. It is shown that the Beltrami regularizer leads to better results than the total variation (TV) regularizer. An analytic comparison to the TV method is carried out and results on synthetic and real data are demonstrated. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 56–63, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20038
Sparse ICA for blind separation of transmitted and reflected images
Authors: Bronstein Alexander M. , Bronstein Michael M. , Zibulevsky Michael , Zeevi Yehoshua Y. 
Published: July 2005

AbstractWe address the problem of recovering a scene recorded through a semireflecting medium (i.e. planar lens), with a virtual reflected image being superimposed on the image of the scene transmitted through the semirefelecting lens. Recent studies propose imaging through a linear polarizer at several orientations to estimate the reflected and the transmitted components in the scene. In this study we extend the sparse ICA (SPICA) technique and apply it to the problem of separating the image of the scene without having any a priori knowledge about its structure or statistics. Recent novel advances in the SPICA approach are discussed. Simulation and experimental results demonstrate the efficacy of the proposed methods.© 2005 Wiley Periodicals, Inc. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 84–91, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20042
Novel bactericidal surface: Catechin‐loaded surface‐erodible polymer prevents biofilm formation
Authors: Maeyama Ryo , Kwon Il Keun , Mizunoe Yoshimitsu , Anderson James M. , Tanaka Masao , Matsuda Takehisa 
Published: July 2005

AbstractWe developed a novel bactericidal surface based on a catechin‐loaded surface‐erodible polymer. (−)‐Epigallocatechin‐3‐gallate (EGCg), which is the main constituent of tea catechins, showed a dose‐dependent inhibitory effect on Escherichia coli biofilm formation and a dose‐dependent enhanced destructive effect on biofilm. EGCg‐immobilized surfaces were prepared by photopolymerization of liquid biodegradable polyesters. The releasing rate was enhanced with an increase in surface‐erosion rate of photocured polymers. Polymers with high releasing capacity dose‐dependently reduced biofilm formation on the surfaces. The confocal laser scanning microscopic and scanning electron microscopic observations revealed that EGCg induced biofilm‐destructing activities, which include bacterial membrane damage, degradation of exopolysaccharides, and detachment of colonized cells. From these results, potential advantages of the clinical use of catechin‐loaded polymer‐coated implants or catheters are discussed in terms of a reduced occurrence of biomaterial‐centered infections without substantial toxicity or adverse effects. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Biological evaluation of calcium alginate microspheres as a vehicle for the localized delivery of a therapeutic enzyme
Authors: Barrias C. C. , Lamghari M. , Granja P. L. , Sá Miranda M. C. , Barbosa M. A. 
Published: July 2005

AbstractGaucher disease (GD) is caused by the decreased activity and/or stability of the lysosomal enzyme glucocerebrosidase (GCR). The available treatment consists in the intravenous administration of exogenous GCR, and is effective in reverting most of the symptoms. However, in terms of bone pathology, which is among the most disabling manifestations, a slow and incomplete response is observed, indicating that adjuvant therapies are necessary to consistently restore GCR activity in bone and accelerate regeneration. In this study, calcium alginate microspheres were analyzed as a vehicle for localized GCR delivery to bone. Results demonstrated that the entrapped enzyme retained full activity and exhibited a broader pH‐dependent activity profile, compared to that of free‐GCR, with improved stability at physiological pH. GCR release profile was established, and it was demonstrated that GCR could be released in a sustained manner. The biological behavior of the system was evaluated by analyzing the uptake of released GCR by GCR‐deficient cells from GD patients, using different techniques: GCR activity measurements, radiolabeling, and cellulose acetate electrophoresis. Results demonstrated that GCR was internalized by cells significantly enhancing the residual enzymatic activity. To achieve an activity reconstitution level comparable to that obtained using free‐GCR, only half of the dose was required with entrapped‐GCR. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Comparison of the effect of surface roughness on the micro/nanotribological behavior of ultra‐high‐molecular‐weight polyethylene (UHMWPE) in air and bovine serum solution
Authors: Check Jason , Karuppiah K. S. Kanaga , Sundararajan Sriram 
Published: July 2005

AbstractTribological properties of materials used in biomedical implants critically affect the performance of the implant. A UHMWPE cup paired with a ceramic ball is a popular combination for implants due to its relatively low wear rate. In this study we investigate the effect of surface roughness of UHMWPE on the friction behavior and onset of wear in a UHMWPE/silicon nitride interface in both dry air and bovine serum environments. Microscale multi‐asperity contact is examined using a ball‐on‐flat reciprocating microtribometer. Nanoscale single‐asperity contact and surface topography are examined using atomic force microscopy. Friction was found to increase with a decrease in surface roughness of the UHMWPE sample in air, which is due to an increase in real area of contact. This trend was seen to disappear or even reverse in serum. This is due to an increase in the interfacial shear stress of the UHMWPE surface when exposed to the serum. This increase is believed to be caused by an adhered layer of protein on the UHMWPE surface. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
In vivo assessment of myocardial blood flow in rat heart using magnetic resonance imaging: Effect of anesthesia
Authors: Iltis Isabelle , Kober Frank , Dalmasso Christiane , Lan Carole , Cozzone Patrick J. , Bernard Monique 
Published: July 2005

AbstractPurposeTo assess the influence of isoflurane and pentobarbital anesthesia and the carrier gases on myocardial blood flow (MBF) in the rat heart in vivo.Materials and MethodsMBF was quantified in vivo using arterial spin‐labeling (ASL) magnetic resonance imaging (MRI). Left ventricular (LV) function was estimated during the same experiment using cine‐MRI. Thirty‐four male Wistar‐Kyoto rats were divided in four groups, one anesthetized with isoflurane in oxygen:nitrous oxide mix (ISO), the three others with intraperitoneal pentobarbital, and breathing either room air (PB), oxygen:nitrous oxide (PB + N2O), or oxygen:nitrogen (PB + N2).ResultsMBF was significantly higher in the ISO and PB + N2O groups vs. PB and in ISO vs. PB + N2, with the following respective MBF values: ISO, 5.9 ± 1.1; PB, 4.0 ± 0.8; PB + N2O, 5.1 ± 1.4; and PB + N2, 4.6 ± 0.8 mL/g/minute, mean ± SD. Ejection fractions were reduced by 10% in PB and PB + N2O rats vs. ISO rats. Cardiac output (CO) and index (CI) were 25 to 30% lower in all rats anesthetized with pentobarbital than with isoflurane.ConclusionIsoflurane and nitrous oxide induce a higher MBF than pentobarbital. Isoflurane also induces a higher ejection fraction in healthy rats. J. Magn. Reson. Imaging 2005;22:242–247. © 2005 Wiley‐Liss, Inc.
Registration of two‐dimensional cardiac images to preprocedural three‐dimensional images for interventional applications
Authors: Smolíková‐Wachowiak Renata , Wachowiak Mark P. , Fenster Aaron , Drangova Maria 
Published: July 2005

AbstractPurposeTo evaluate the accuracy and efficiency of rigid‐body registration of two‐dimensional fast cine and real‐time cardiac images to high‐resolution and SNR three‐dimensional preprocedural reference volumes for application during MRI‐guided interventional procedures.Materials and MethodsMutual information (MI) and correlation ratio (CR) similarity measures were evaluated. The dependence of registration accuracy and efficiency on different resolution and SNR parameters, and also on cardiac‐phase differences was evaluated in a porcine model. Two‐dimensional images were initially misoriented at distances (d) of 2–10 mm, and rotations of ±5° about all axes. Registration error and computation time were evaluated, and performance was also assessed visually.ResultsThe maximum registration error using MI (<2.7 mm and <3.6°) occurred for d = 10 mm, misrotation of ±5°, and relative SNR = 1. The computation time was 15 seconds for MI and 10 seconds for CR.ConclusionRegistration accuracy was not highly dependent on the relative timing, within the cycle, between the two‐dimensional and three‐dimensional images. Registration using CR was faster than that using MI, although accuracy was marginally higher with MI. J. Magn. Reson. Imaging 2005;22:219–228. © 2005 Wiley‐Liss, Inc.
Partial rescue of the perfusion deficit area by thrombolysis
Authors: Seitz Rüdiger J. , Meisel Stefanie , Moll Marek , Wittsack Hans‐Jörg , Junghans Ulrich , Siebler Mario 
Published: July 2005

AbstractPurposeTo investigate the evolution of the perfusion deficit area following systemic thrombolysis with recombinant tissue plasminogen activator (rtPA) in a clinical study on acute cerebral ischemia.Materials and MethodsWe performed volumetric measurements of the acute ischemic lesions in MR images of perfusion (TTP, MTT, and rCBV) and in diffusion‐weighted (DW) images, as well as the manifest stroke lesions in T2‐weighted MR images on day 8. We compared the data of 29 patients who were subjected to systemic thrombolysis with those of 18 patients who were not eligible for thrombolysis.ResultsIn the treated patients there were prominent MTT/DWI and TTP/DWI mismatches (P < 0.0006). The acute TTP volumes were smaller than the acute MTT volumes, but as large as the T2 lesions on day 8. The MTT/T2 lesion volume reduction was significant (P < 0.03) in patients who received the GPIIb/IIIa receptor antagonist tirofiban (N = 13) in addition to the low‐dose rtPA. This corresponded to a greater neurological improvement compared to patients who received rtPA alone (P < 0.05). In contrast, in the nontreated patients the initial MTT and TTP lesion volumes were of similar magnitude and predicted the T2 lesions on day 8. In the treated and nontreated patients the TTP lesion signified the viability threshold of acute ischemia, which corresponded to a rCBF of 25 ± 11 mL/100 g/min.ConclusionThe perfusion deficit area comprises the ischemic core that is destined to undergo necrosis, and an ischemic rim that is salvageable by systemic thrombolysis. J. Magn. Reson. Imaging 2005;22:199–205. © 2005 Wiley‐Liss, Inc.
Spiral coronary angiography using a blood pool agent
Authors: Ringgaard Steffen , Pedersen Michael , Rickers Jonas , Johansson Lars O. , Börnert Peter , Pedersen Erik M. 
Published: July 2005

AbstractPurposeTo experimentally investigate the optimum dose of an iron‐oxide‐based blood pool agent for spiral coronary MR angiography (MRA), and the difference between single and multiple spiral excitations in each cardiac cycle.Materials and MethodsImages using single and triple spiral excitations in each cardiac cycle were obtained in late diastole of the left main coronary artery in eight pigs following an inversion prepulse. Measurements were obtained before and after injection of increasing doses of an iron oxide blood pool agent (Clariscan) corresponding to concentrations of 0.8, 2.2, and 3.9 mg Fe/kg BW. The signal‐to‐noise ratio (SNR) and contrast‐to‐noise ratio (CNR) were measured.ResultsFor 0.8 mg Fe/kg BW relative to precontrast values, a significant increase was observed for both one (SNR: 2.3, CNR: 3.8) and three (SNR: 1.4, CNR: 2.2) excitations (P < 0.01). When the dose was increased from 0.8 mg Fe/kg BW to 2.2 mg Fe/kg BW, only the SNR (P < 0.01) increased further. Significantly higher CNR (1.6–1.8) and SNR (1.4–1.6) values were seen for one excitation relative to three excitations at all concentrations (P < 0.05).ConclusionAt low concentrations, an iron oxide blood pool agent can increase SNR and CNR significantly with both single excitation and triple excitations using an inversion‐prepared spiral acquisition scheme. At higher concentrations, T2* effects reduce image quality. J. Magn. Reson. Imaging 2005;22:213–218. © 2005 Wiley‐Liss, Inc.
Left ventricular diastolic function compared with T2* cardiovascular magnetic resonance for early detection of myocardial iron overload in thalassemia major
Authors: Westwood Mark A. , Wonke Beatrix , Maceira Alicia M. , Prescott Emma , Walker J. Malcolm , Porter John B. , Pennell Dudley J. 
Published: July 2005

AbstractPurposeTo compare left ventricular (LV) diastolic function with myocardial iron levels in beta thalassemia major (TM) patients, using cardiovascular magnetic resonance (CMR).Materials and MethodsWe studied 67 regularly transfused patients with TM and 22 controls matched for age, gender, and body surface area. The early peak filling rate (EPFR) and atrial peak filling rate (APFR) were determined from high‐temporal‐resolution ventricular volume‐time curves. Myocardial iron estimation was achieved using myocardial T2* measurements.ResultsMyocardial iron loading was found in 46 TM patients (69%), in whom the EPFR correlated poorly with T2* (r = −0.20, P = 0.19). The APFR (r = 0.49, P < 0.001) and EPFR/APFR ratio (r = −0.62, P < 0.001) correlated better with T2*. The sensitivity of the diastolic parameters for detecting myocardial iron loading ranged from 4% (EPFR and APFR) to 17% (EPFR/APFR ratio).ConclusionMyocardial iron overload results in diastolic myocardial dysfunction, but low sensitivity limits the use of a single estimation for early detection of iron overload, for which T2* has a superior categorical limit of normality. J. Magn. Reson. Imaging 2005;22:229–233. © 2005 Wiley‐Liss, Inc.
Evaluation of in‐stent stenosis by magnetic resonance phase‐velocity mapping in nickel‐titanium stents
Authors: Holton Andrea D. , Walsh Edward G. , Brott Brigitta C. , Venugopalan Ramakrishna , Hershey Bradley , Ito Yasushi , Shih Alan , Koomullil Roy , Anayiotos Andreas S. 
Published: July 2005

AbstractPurposeTo evaluate different grades of in‐stent stenosis in a nickel‐titanium stent with MRI.Materials and MethodsMagnetic resonance phase velocity mapping (MR‐PVM) was used to measure flow velocity through a 9‐mm NiTi stent with three different degrees of stenosis in a phantom study. The tested stenotic geometries were 1) axisymmetric 75%, 2) axisymmetric 90%, and 3) asymmetric 50%. The MR‐PVM data were subsequently compared with the velocities from computational fluid dynamic (CFD) simulations of identical conditions.ResultsGood quantitative agreement in velocity distribution for the 50% and 75% stenoses was observed. The agreement was poor for the 90% stenosis, most likely due to turbulence and the high‐velocity gradients found in the small luminal area relative to the pixel resolution in our imaging settings.ConclusionThe accuracy of the MRI velocities inside the stented area renders MRI a modality that may be used to assess moderate to severe in‐stent restenosis (ISR) in medium‐sized vascular stents in peripheral vessels, such as the iliac, carotid, and femoral arteries. Advances in MR instrumentation may provide sufficient resolution to obtain adequate velocity information from smaller vessels, such as the coronary arteries, and allow MRI to substitute for invasive and expensive catheterization procedures currently in clinical use. J. Magn. Reson. Imaging 2005;22:248–257. © 2005 Wiley‐Liss, Inc.
Arylsulfonates as sole source of sulfur for Clostridium pasteurianum DSM 12136
Authors: Chien Chih‐Ching 
Published: July 2005

AbstractA variety of arylsulfonates were examined for their ability to support growth of Clostridium pasteurianum as sole source of sulfur. Among the eleven different arylsulfonates tested, six of them (benzenesulfonate, 4‐toluenesulfonate, 4‐xylene‐2‐sulfonate, 4‐aminobenzenesulfonate, 4‐sulfobenzoic acid, 1,3‐benzenedisulfonate) could serve as sole sulfur source for C. pasteurianum DSM 12136. None of the sulfonates tested could serve as sole sulfur source for C. pasteurianum ATCC 6013. The two C. pasteurianum in this study could not utilize any of these sulfonates as sole carbon and energy source. We demonstrated that desulfonation of arylsulfonates could take place under anoxic conditions and the sulfur atom of these compounds could be utilized as sole source of sulfur by anaerobic bacteria. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of bacteriocins produced by lactic acid bacteria isolated from spoiled black olives
Authors: Todorov Svetoslav D. , Dicks Leon M. T. 
Published: July 2005

AbstractBacteriocin‐producing strains of Lactobacillus plantarum ST23LD and ST341LD, Enterococcus faecium ST311LD and Leuconostoc mesenteroides subsp. mesenteroides ST33LD were isolated from the brine of spoiled black olives. The bacteriocins produced by all four strains inhibited the growth of Gram‐positive bacteria (E. faecalis, L. casei and Streptococcus pneumoniae), but also Escherichia coli and Pseudomonas aeruginosa. Strain ST23LD produced two bacteriocins (ST23LDa and ST23LDb of approximately 3.0 and 14.0 kDa, respectively), with a combined maximum level of activity of 25600 AU/ml after 18 h of growth. The same level of activity was recorded for bacteriocin ST341LD (approximately 3.0 kDa), but after 16 h. Bacteriocins ST311LD (ca. 2.3 kDa) and ST33LD (ca. 2.7 kDa) were produced at much lower levels (6400 AU/ml), and only after 20 h of growth. Bacteriocin activity was destroyed after treatment with proteolytic enzymes and Triton X, but not when treated with α‐amylase, SDS, Tween 20, Tween 80, urea and EDTA, or when heated for 20 min at 121 °C. Addition of bacteriocins ST23LD, ST341LD and ST311LD to cells of Lactobacillus casei LHS in logarithmic phase resulted in growth inhibition for one hour, followed by a slight increase in optical density over the next seven hours. Bacteriocin ST33LD also inhibited the growth of strain LHS, but to a lesser extent. Bacteriocins ST23LD, ST341LD and ST33LD remained at the same level of activity for 6 h at pH < 4.0. However, the activity of bacteriocin ST311LD decreased by 50% within 2 h at pH 4.4. The possibility of the bacteriocin adsorbing to the producer cell and proteolytic degradation is unlikely. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Annual trace element cycles in calcite–aragonite speleothems: evidence of drought in the western Mediterranean 1200–1100 yr BP
Authors: McMillan Emily A. , Fairchild Ian J. , Frisia Silvia , Borsato Andrea , McDermott Frank 
Published: July 2005

AbstractEach of two calcitic stalagmites from Grotte de Clamouse, Herault, southern France, displays a discrete aragonite layer dated at around 1100 yr BP. The layer of fanning aragonite ray crystals is immediately preceded by calcite with Mg and Sr compositions that are uniquely high for the past 3 kyr. Trace element compositions close to the boundary between original aragonite and calcite are consistent with quasi‐equilibrium partitioning of trace elements between the phases. Study of modern dripwaters demonstrates that pronounced covariation of Mg/Ca and Sr/Ca ratios in dripwater occurs owing to large amounts of calcite precipitation upflow of the drips that fed the stalagmites. Trace element to Ca ratios are enhanced during seasonally dry periods. Ion microprobe data demonstrate a pronounced covariation of trace elements, including Mg and Sr in calcite, and Sr, U and Ba in aragonite. The mean peak spacing is close to the long‐term mean of annual growth rates determined by differences in U‐series ages and so the trace element peaks are interpreted as annual. The trace element chemistry of the stalagmites on annual to inter‐annual scales thus directly reflects the amounts of prior calcite precipitation, interpreted as an index of aridity. The longer‐term context is a multi‐decadal period of aridity (1200–1100 yr BP) possibly correlated with an analogous episode in Central America. The arid period culminated in the nucleation of aragonite, but within a decade was followed by a return to precursor conditions. Copyright © 2005 John Wiley & Sons, Ltd.
Late Quaternary climate change record from two long sediment cores from Guaymas Basin, Gulf of California
Authors: Cheshire Heather , Thurow Jürgen , Nederbragt Alexandra J. 
Published: July 2005

AbstractModern Guaymas Basin (Gulf of California, Mexico) is a region of high diatom productivity where exceptional preservation factors maintain biannually alternating sediment deposition as annual varves. New sediment cores from Guaymas Basin (MD02‐2512 and MD02‐2515) present the opportunity to construct climate records from below the last glacial period. A low‐resolution age model has been constructed from oxygen isotope analysis, correlation with other dated short piston cores from Guaymas Basin and an estimate of sedimentation rate. MD02‐2512 from eastern Guaymas Basin has an age range from the Holocene to late marine isotope stage 6 (MIS 6); MD02‐2515 from western Guaymas Basin has an age range from ∼8000 to 40 000 yr. Shipboard analyses of colour reflectance, magnetic susceptibility and sediment density are combined with continuous X‐ray fluorescence scans to reconstruct a picture of glacial climate in the Gulf of California. Eastern Guaymas Basin is affected by glacial sea level fall, which results in a drastic change in productivity rates and sediment type. The laminated record of MIS 5 allows comparison with the Holocene, showing a similarity of sedimentation patterns during deglaciation and a series of very rapid variations just prior to the last glaciation. In western Guaymas Basin there are a series of Younger Dryas‐like events during the glacial, typified by low productivity and high terrigenous input. Long‐term climate and productivity changes appear to be caused by the southward displacement of the Subtropical High pressure zone. Copyright © 2005 John Wiley & Sons, Ltd.