bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antimicrobial Activity of Plant Extracts Against Salmonella Typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes on Fresh Lettuce
Authors: Kim Sung‐Youn , Kang Dong‐Hyun , Kim Jin‐Ki , Ha Yong‐Geun , Hwang Ju Young , Kim Taewan , Lee Seon‐Ho 
Published: December 2010

Abstract:  Plant extracts have been found to be effective in reducing microorganisms. This study evaluated antimicrobial activity of 12 plant extracts against Salmonella Typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes by using a disk diffusion assay, and Syzygium aromaticum (clove) showed the highest inhibitory effect. To investigate the efficacy of clove extract that inactivates pathogens on lettuce, inoculated lettuce with S. Typhimurium, E. coli O157:H7, and L. monocytogenes was treated with diluted clove extracts or distilled water for 0, 1, 3, 5, and 10 min. Clove extract treatment significantly reduced populations of the 3 tested pathogens from the surface of lettuce.Practical Application:  This result indicated that clove extract is a useful antimicrobial agent to reduce the microbial level of foodborne pathogens on fresh lettuce. It also might be a natural antimicrobial for reducing or replacing chemical sanitizers in food preservation.
Automatic Nematode Detection in Cod Fillets (Gadus Morhua) by Transillumination Hyperspectral Imaging
Authors: Sivertsen Agnar Holten , Heia Karsten , Stormo Svein Kristian , Elvevoll Edel , Nilsen Heidi 
Published: December 2010

Abstract:  Traditional quality control of cod fillets is currently made by manual inspection on candling tables. This is a time consuming and expensive operation, contributing to a significant share of the cost with cod fillet production. In this study, transillumination hyperspectral imaging was implemented as a method for automatic nematode detection in cod fillets moving on a conveyer belt, and evaluated on industrially processed cod fillets. An overall detection rate of 58% of all nematodes (N= 922), with detection rate of 71% and 46% for dark and pale nematodes, respectively, is reported. This is comparable, or better, than what is reported for manual inspection under industrial conditions. The false alarm rate was high, with 60% of the fillets reported with one or more false alarms. These results show that the method is promising, but needs further refinements to reduce the false alarm rate and increase the imaging speed from 25 to 400 mm/s.Practical Application:  Manual inspection of cod fillets is a huge bottleneck for the industry, accounting for half the production cost with cod fillet processing and reducing the processing speed. Transillumination hyperspectral imaging has the potential to reduce the manual labor required for cod fillet inspection and hence reduce the cost and increase the end product quality.
Heparin‐induced thrombocytopenia: evaluation of IgG and IgGAM ELISA assays
Authors: MOREL‐KOPP M.‐C. , ABOUD M. , TAN C. W. , KULATHILAKE C. , WARD C. 
Published: December 2010

SummaryBackground:  Heparin‐induced thrombocytopenia (HIT) is a rare complication of heparin therapy resulting from antibody production to platelet factor 4 and heparin complexes (H‐PF4).Methods:  We have evaluated four enzyme‐linked immunosorbent assay (ELISA)‐based screening tests to identify the best assay(s) with the highest specificity but without underdiagnosis of HIT. As functional assays are difficult to perform, ELISAs are useful to provide clinicians with a timely answer. Over a 10‐month period, all samples (N = 107) referred to our laboratory were tested for HIT antibodies using four commercially available ELISA kits, two detecting IgG/A/M anti‐H‐PF4 antibodies and the other two IgG specific.Results:  Twenty‐eight samples were positive by at least one assay; IgGAM ELISAs were found to be more sensitive with 24 samples positive by Asserachrom IgGAM and 23 by Zymutest IgGAM. Only 18 samples were positive by GTI‐PF4‐IgG and Zymutest IgG. The gold standard serotonin release assay (SRA) was used as a confirmation assay, and 11/28 samples tested positive. All these SRA‐positive samples were positive by all four assays. None of the IgGAM‐only‐positive samples was found to be positive by SRA suggesting a better specificity for the IgG‐only assays.Conclusion:  Our data strongly support the use of IgG‐only assays for the detection of HIT antibodies.
Evaluation of activated partial thromboplastin time (aPTT) reagents for application in biomedical diagnostic device development
Authors: DUDEK M. M. , HARRIS L. F. , KILLARD A. J. 
Published: December 2010

SummaryIntroduction:  The most commonly used test for monitoring heparin therapy is the activated partial thromboplastin time (aPTT). The response of available aPTT reagents to heparin varies significantly. The aim of this study was to highlight the differences between aPTT reagents stored in a dried format to select the most suitable formulations to be used for the development of point‐of‐care diagnostic devices used for monitoring of unfractionated heparin dose response.Methods:  Ten reagents were analysed in terms of their performance in liquid and in dried form after storage for 24 h and 14 days. Performance was assessed by measurement of the clotting time (CT) as evidenced by the onset of thrombin formation using a chromogenic thrombin substrate in plasma samples activated with these formulations.Results:  Reagents in all of the three forms tested (liquid, 24 h and 14 days) resulted in significant shortening of CTs in comparison with the nonactivated plasma CT. Liquids returned more rapid CTs in comparison with dried reagents. Most of the reagents were more sensitive to heparin in dried, rather than in liquid form. Dried reagents based on kaolin as a surface activator were notably more effective in achieving short CT than others, while dried reagents composed of silica and synthetic phospholipids were the most sensitive to heparin.Conclusion:  Two reagents, namely aPTT‐SP and SynthASIL both of which are based on synthetic phospholipids and silica, were identified as promising candidates for incorporation into point‐of‐care diagnostic device platforms as dried reagents.
Early Efficacy of an α1 Adrenoceptor Antagonist, Naftopidil, against Lower Urinary Tract Symptoms Suggestive of Benign Prostatic Hyperplasia
Authors: ISHIZUKA Osamu , NISHIZAWA Osamu , TAKEDA Masayuki , NOMURA Teruhisa , KAGAWA Susumu 
Published: December 2010

Objectives: The present study investigated the early efficacy of naftopidil against lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH).Methods: Subjects comprised patients with LUTS suggestive of BPH who were followed prospectively for 8 weeks. Inclusion criteria were: (i) international prostate symptom score (IPSS) ≥8; (ii) no previous treatment for BPH; and (iii) eligibility for naftopidil monotherapy. IPSS and quality of life index were evaluated, and uroflowmetry and residual urine volume were determined optionally. In the previous study, patients who demonstrated a decrease in total American Urological Association symptom score of 25% or more from baseline were considered responders. The ratio of onset of efficacy of naftopidil was calculated by the ratio of the number of responder in each group with the starting dose.Results: Naftopidil efficacy was analyzed for 243 patients. Significant improvement of IPSS was achieved within 1–3 days after medication. Starting dosage and average dosage were identified as factors associated with the period until onset of naftopidil efficacy. Onset of efficacy was significantly quicker with a starting dosage of 50 mg/day as compared with 25 mg/day (P = 0.0047). However, ratios of onset of efficacy with starting dosages of 25, 50 and 75 mg/day were 77.9, 76.7 and 85.7%, respectively, showing no significant difference between groups (P = 0.7463). Duration to onset of efficacy with naftopidil dosage ≥50 mg/day was 11.2 days, significantly early compared to dosage <50 mg/day. Incidence of adverse effect was 3.8%.Conclusion: Naftopidil showed early effects against LUTS suggestive of BPH within a few days.
A statistical, task‐based evaluation method for three‐dimensional x‐ray breast imaging systems using variable‐background phantoms
Authors: Park Subok , Jennings Robert , Liu Haimo , Badano Aldo , Myers Kyle 
Published: December 2010

Purpose:For the last few years, development and optimization of three‐dimensional (3D) x‐ray breast imaging systems, such as digital breast tomosynthesis (DBT) and computed tomography, have drawn much attention from the medical imaging community, either academia or industry. However, there is still much room for understanding how to best optimize and evaluate the devices over a large space of many different system parameters and geometries. Current evaluation methods, which work well for 2D systems, do not incorporate the depth information from the 3D imaging systems. Therefore, it is critical to develop a statistically sound evaluation method to investigate the usefulness of inclusion of depth and background‐variability information into the assessment and optimization of the 3D systems.Methods:In this paper, we present a mathematical framework for a statistical assessment of planar and 3D x‐ray breast imaging systems. Our method is based on statistical decision theory, in particular, making use of the ideal linear observer called the Hotelling observer. We also present a physical phantom that consists of spheres of different sizes and materials for producing an ensemble of randomly varying backgrounds to be imaged for a given patient class. Lastly, we demonstrate our evaluation method in comparing laboratory mammography and three‐angle DBT systems for signal detection tasks using the phantom's projection data. We compare the variable phantom case to that of a phantom of the same dimensions filled with water, which we call the uniform phantom, based on the performance of the Hotelling observer as a function of signal size and intensity.Results:Detectability trends calculated using the variable and uniform phantom methods are different from each other for both mammography and DBT systems.Conclusions:Our results indicate that measuring the system's detection performance with consideration of background variability may lead to differences in system performance estimates and comparisons. For the assessment of 3D systems, to accurately determine trade offs between image quality and radiation dose, it is critical to incorporate randomness arising from the imaging chain including background variability into system performance calculations.
An iterative method for tomographic x‐ray perfusion estimation in a decomposition model‐based approach
Authors: Neukirchen Christoph , Giordano Marco , Wiesner Steffen 
Published: December 2010

Purpose:X‐ray based tomographic blood perfusion imaging requires recovery of contrast time‐attenuation‐curves from dynamic projection data. When using slowly rotating imaging systems, this task is challenging due to nonsimultaneous projection acquisition. A dynamic reconstruction method is proposed that aims at compensating the lack of simultaneously acquired information by incorporating prior knowledge about the expected temporal contrast dynamics.Methods:A decomposition model using temporal basis functions to approximate time‐attenuation‐curves is integrated into an iterative tomographic reconstruction method. The computationally efficient implementation of the proposed approach makes use of standard forward‐projections and backprojections, as well as scalar products in image space. The critical issue of projection noise propagation is tackled by the application of regularization which is realized by the early stopping of iteration cycles and by the proper selection of smooth temporal basis functions. The performance of the proposed dynamic reconstruction approach is evaluated in a simulation study concerning various aspects: Noise propagation and regularization, specification of the temporal model, and type of acquisition mode.Results:The evaluation based on dynamic phantom data indicates that tomographic recovery of contrast time‐attenuation‐curves in tissue can be achieved with an average range of accuracy of (with respect to dynamic peak attenuation) under ideal noise‐free conditions. The relative estimation error for arterial time‐attenuation‐curves is in the range of 8%, which is due to faster contrast dynamics in the artery. In general, performance depends on the level of acquired information contained in the projection data, which is mainly influenced by the type of rotational acquisition mode; restrictions in angular range and speed can lead to limited accuracy. The analysis of propagated projection noise in a statistical bias‐variance framework reveals relative noise levels in estimated time‐attenuation‐curves of 3%–4% in tissue regions and below 1% in vessels when using optimized settings for regularization. Here, the effect of noise suppression depends on the interrelation between the number of iteration cycles and the constraints imposed by the temporal decomposition model.Conclusions:For usage with slowly rotating imaging systems, the presented model‐based iterative dynamic reconstruction method is capable of recovering contrast time‐attenuation‐curves related to tissue perfusion. The proposed regularization framework is an effective means to limit the impact of projection noise, which is a factor dominating estimation accuracy in tissue regions.
Target tracking using DMLC for volumetric modulated arc therapy: A simulation study
Authors: Sun Baozhou , Rangaraj Dharanipathy , Papiez Lech , Oddiraju Swetha , Yang Deshan , Li H. Harold 
Published: December 2010

Purpose:Target tracking using dynamic multileaf collimator (DMLC) is a promising approach for intrafraction motion management in radiation therapy. The purpose of this work is to develop a DMLC tracking algorithm capable of delivering volumetric‐modulated arc therapy (VMAT) to the targets that experience two‐dimensional (2D) rigid motion in the beam's eye view.Methods:The problem of VMAT delivery to moving targets is formulated as a control problem with constraints. The relationships between gantry speed, gantry acceleration, MLC leaf‐velocity, dose rate, and target motion are derived. An iterative search algorithm is developed to find numerical solutions for efficient delivery of a specific VMAT plan to the moving target using 2D DMLC tracking. The delivery of five VMAT lung plans is simulated. The planned and delivered fluence maps in the target‐reference frame are calculated and compared.Results:The simulation demonstrates that the 2D tracking algorithm is capable of delivering the VMAT plan to a moving target fast and accurately without violating the machine constraints and the integrity of the treatment plan. The average delivery time is only 29 s longer than that of no‐tracking delivery, 101 versus 72 s, respectively. The fluence maps are normalized to 200 MU and the average root‐mean‐square error between the desired and the delivered fluence is 2.1 MU, compared to 14.8 MU for no‐tracking and 3.6 MU for one‐dimensional tracking.Conclusions:A locally optimal MLC tracking algorithm for VMAT delivery is proposed, aiming at shortest delivery time while maintaining treatment plan invariant. The inconsequential increase of treatment time due to DMLC tracking is clinically desirable, which makes VMAT with DMLC tracking attractive in treating moving tumors.
Joint correction of respiratory motion artifact and partial volume effect in lung/thoracic PET/CT imaging
Authors: Chang Guoping , Chang Tingting , Pan Tinsu , Clark John W. , Mawlawi Osama R. 
Published: December 2010

Purpose:Respiratory motion artifacts and partial volume effects (PVEs) are two degrading factors that affect the accuracy of image quantification in PET/CT imaging. In this article, the authors propose a joint motion and PVE correction approach (JMPC) to improve PET quantification by simultaneously correcting for respiratory motion artifacts and PVE in patients with lung/thoracic cancer. The objective of this article is to describe this approach and evaluate its performance using phantom and patient studies.Methods:The proposed joint correction approach incorporates a model of motion blurring, PVE, and object size/shape. A motion blurring kernel (MBK) is then estimated from the deconvolution of the joint model, while the activity concentration (AC) of the tumor is estimated from the normalization of the derived MBK. To evaluate the performance of this approach, two phantom studies and eight patient studies were performed. In the phantom studies, two motion waveforms—a linear sinusoidal and a circular motion—were used to control the motion of a sphere, while in the patient studies, all participants were instructed to breathe regularly. For the phantom studies, the resultant MBK was compared to the true MBK by measuring a correlation coefficient between the two kernels. The measured sphere AC derived from the proposed method was compared to the true AC as well as the ACs in images exhibiting PVE only and images exhibiting both PVE and motion blurring. For the patient studies, the resultant MBK was compared to the motion extent derived from a 4D‐CT study, while the measured tumor AC was compared to the AC in images exhibiting both PVE and motion blurring.Results:For the phantom studies, the estimated MBK approximated the true MBK with an average correlation coefficient of 0.91. The tumor ACs following the joint correction technique were similar to the true AC with an average difference of 2%. Furthermore, the tumor ACs on the PVE only images and images with both motion blur and PVE effects were, on average, 75% and 47.5% (10%) of the true AC, respectively, for the linear (circular) motion phantom study. For the patient studies, the maximum and mean AC/SUV on the PET images following the joint correction are, on average, increased by 125.9% and 371.6%, respectively, when compared to the PET images with both PVE and motion. The motion extents measured from the derived MBK and 4D‐CT exhibited an average difference of 1.9 mm.Conclusions:The proposed joint correction approach can improve the accuracy of PET quantification by simultaneously compensating for the respiratory motion artifacts and PVE in lung/thoracic PET/CT imaging.
A comprehensive study of the Gafchromic EBT2 radiochromic film. A comparison with EBT
Authors: Andrés C. , del Castillo A. , Tortosa R. , Alonso D. , Barquero R. 
Published: December 2010

Purpose:Radiochromic film has become an important tool to assess complex dose distributions. In particular, EBT was accepted by the scientific community as a reference two‐dimensional detector. Recently, Gafchromic EBT2 has replaced old film, providing new improvements in both accuracy and handling.Methods:This work presents a dosimetric study of the new Gafchromic EBT2 using an Epson 10000XL flatbed scanner, also comparing the results with EBT film as reference when necessary. The most important film characteristics have been studied, such as ambient light sensitivity, different possibilities of the three RGB color channels, postirradiation development, high dose behavior, exposition at temperatures similar to the human body, and dependence on orientation during the scanning process.Results:The results obtained confirm a considerably lower sensitivity to ambient light of EBT2, as well as a fast stabilization of the film within 2 h. It has also been found that the green channel has a better behavior at high dose levels up to 35 Gy, in addition to good behavior of the red channel at doses below 10 Gy. Other features, such as temperature independence and scanning orientation dependence, have also been shown.Conclusions:Gafchromic EBT2 can be used for clinical practice in the same way as the old EBT film. However, a much easier handling as the result of all new enhancements improves film behavior, expanding in this way the potential applications of radiochromic film dosimetry.
The role of x‐ray Swank factor in energy‐resolving photon‐counting imaging
Authors: Tanguay Jesse , Kim Ho Kyung , Cunningham Ian. A. 
Published: December 2010

Purpose:Energy‐resolved x‐ray imaging has the potential to improve contrast‐to‐noise ratio by measuring the energy of each interacting photon and applying optimal weighting factors. The success of energy‐resolving photon‐counting (EPC) detectors relies on the ability of an x‐ray detector to accurately measure the energy of each interacting photon. However, the escape of characteristic emissions and Compton scatter degrades spectral information. This article makes the theoretical connection between accuracy and imprecision in energy measurements with the x‐ray Swank factor for, Si, CdZnTe, and ‐based detectors.Methods:For a detector that implements adaptive binning to sum all elements in which x‐ray energy is deposited for a single interaction, energy imprecision is shown to depend on the Swank factor for a large element with x rays incident at the center. The response function for each converter material is determined using Monte Carlo methods and used to determine energy accuracy, Swank factor, and relative energy imprecision in photon‐energy measurements.Results:For each material, at energies below the respective K edges, accuracy is close to unity and imprecision is only a few percent. Above the K‐edge energies, characteristic emission results in a drop in accuracy and precision that depends on escape probability. In Si, and to some extent, Compton‐scatter escape also degrades energy precision with increasing energy. The influence of converter thickness on energy accuracy and imprecision is modest for low‐Z materials but becomes important when using high‐Z materials at energies greater than the K‐edge energies.Conclusions:Accuracy and precision in energy measurements by EPC detectors are determined largely by the energy‐dependent x‐ray Swank factor. Modest decreases in the Swank factor (5%–15%) result in large increases in relative imprecision (30%–40%).
Multiscale entropy of laser Doppler flowmetry signals in healthy human subjects
Authors: Humeau Anne , Buard Benjamin , Mahé Guillaume , Rousseau David , Chapeau‐Blondeau François , Abraham Pierre 
Published: December 2010

Purpose:The cardiovascular system (CVS) regulation can be studied from a central viewpoint, through heart rate variability (HRV) data, and from a peripheral viewpoint, through laser Doppler flowmetry (LDF) signals. Both the central and peripheral CVSs are regulated by several interacting mechanisms, each having its own temporal scale. The central CVS has been the subject of many multiscale studies. By contrast, these studies at the level of the peripheral CVS are very recent. Among the multiscale studies performed on the central CVS data, multiscale entropy has been proven to give interesting physiological information for diagnostic purposes. However, no multiscale entropy analysis has been performed on LDF signals. The authors' goal is therefore to propose a first multiscale entropy study of LDF data recorded in healthy subjects.Methods:The LDF signals recorded in the forearm of seven healthy subjects are processed. Their period sampling is, and coarse‐graining scales from to are studied. Also, for validation, the algorithm is first tested on synthetic signals of known theoretical multiscale entropy.Results:The results reveal nonmonotonic evolution of the multiscale entropy of LDF signals, with a maximum at small scales around and a minimum at longer scales around , singling out in this way two distinctive scales where the LDF signals undergo specific changes from high to low complexity. This also marks a strong contrast with the HRV signals that usually display a monotonic increase in the evolution of the multiscale entropy.Conclusions:Multiscale entropy of LDF signals in healthy subjects shows variation with scales. Moreover, as the variation pattern observed appears similar for all the tested signals, multiscale entropy could potentially be a useful stationary signature for LDF signals, which otherwise are probe‐position and subject dependent. Further work could now be conducted to evaluate possible diagnostic purposes of the multiscale entropy of LDF signals.