Unrestricted Hepatocyte Transduction with Adeno-Associated Virus Serotype 8 Vectors in Mice

Science.gov (United States)

Nakai, Hiroyuki; Fuess, Sally; Storm, Theresa A.; Muramatsu, Shin-ichi; Nara, Yuko; Kay, Mark A.

2005-01-01

Recombinant adeno-associated virus (rAAV) vectors can mediate long-term stable transduction in various target tissues. However, with rAAV serotype 2 (rAAV2) vectors, liver transduction is confined to only a small portion of hepatocytes even after administration of extremely high vector doses. In order to investigate whether rAAV vectors of other serotypes exhibit similar restricted liver transduction, we performed a dose-response study by injecting mice with β-galactosidase-expressing rAAV1 and rAAV8 vectors via the portal vein. The rAAV1 vector showed a blunted dose-response similar to that of rAAV2 at high doses, while the rAAV8 vector dose-response remained unchanged at any dose and ultimately could transduce all the hepatocytes at a dose of 7.2 × 1012 vector genomes/mouse without toxicity. This indicates that all hepatocytes have the ability to process incoming single-stranded vector genomes into duplex DNA. A single tail vein injection of the rAAV8 vector was as efficient as portal vein injection at any dose. In addition, intravascular administration of the rAAV8 vector at a high dose transduced all the skeletal muscles throughout the body, including the diaphragm, the entire cardiac muscle, and substantial numbers of cells in the pancreas, smooth muscles, and brain. Thus, rAAV8 is a robust vector for gene transfer to the liver and provides a promising research tool for delivering genes to various target organs. In addition, the rAAV8 vector may offer a potential therapeutic agent for various diseases affecting nonhepatic tissues, but great caution is required for vector spillover and tight control of tissue-specific gene expression. PMID:15596817

Reducing and filtering point clouds with enhanced vector quantization.

Science.gov (United States)

Ferrari, Stefano; Ferrigno, Giancarlo; Piuri, Vincenzo; Borghese, N Alberto

2007-01-01

Modern scanners are able to deliver huge quantities of three-dimensional (3-D) data points sampled on an object's surface, in a short time. These data have to be filtered and their cardinality reduced to come up with a mesh manageable at interactive rates. We introduce here a novel procedure to accomplish these two tasks, which is based on an optimized version of soft vector quantization (VQ). The resulting technique has been termed enhanced vector quantization (EVQ) since it introduces several improvements with respect to the classical soft VQ approaches. These are based on computationally expensive iterative optimization; local computation is introduced here, by means of an adequate partitioning of the data space called hyperbox (HB), to reduce the computational time so as to be linear in the number of data points N, saving more than 80% of time in real applications. Moreover, the algorithm can be fully parallelized, thus leading to an implementation that is sublinear in N. The voxel side and the other parameters are automatically determined from data distribution on the basis of the Zador's criterion. This makes the algorithm completely automatic. Because the only parameter to be specified is the compression rate, the procedure is suitable even for nontrained users. Results obtained in reconstructing faces of both humans and puppets as well as artifacts from point clouds publicly available on the web are reported and discussed, in comparison with other methods available in the literature. EVQ has been conceived as a general procedure, suited for VQ applications with large data sets whose data space has relatively low dimensionality.

Strategies to reduce radiation dose in cardiac PET/CT

Energy Technology Data Exchange (ETDEWEB)

Wu, Tung Hsin; Wu, Nien-Yun [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan (China); Wang, Shyh-Jen [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan (China); Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (China); Wu, Jay [Institute of Radiological science, Central Taiwan University of Science and Technology, Taichung, Taiwan (China); Mok, Greta S.P. [Department of Electrical and Electronics Engineering, Faculty of Science and Technology, University of Macau, Macau (China); Yang, Ching-Ching, E-mail: g39220003@yahoo.com.tw [Department of Radiological Technology, Tzu Chi College of Technology, 880, Sec.2, Chien-kuo Rd. Hualien 970, Taiwan (China); Huang, Tzung-Chi, E-mail: tzungchi.huang@mail.cmu.edu.tw [Department of Biomedical Imaging and Radiological Science, China Medical University, No.91 Hsueh-Shih Road, Taichung 40402, Taiwan (China)

2011-08-21

Background: Our aim was to investigate CT dose reduction strategies on a hybrid PET/CT scanner for cardiac applications. Materials: Image quality and dose estimation of different CT scanning protocols for CT coronary angiography (CTCA), and CT-based attenuation correction for PET imaging were investigated. Fifteen patients underwent CTCA, perfusion PET imaging at rest and under stress, and FDG PET for myocardial viability. These patients were divided into three groups based on the CTCA technique performed: retrospectively gated helical (RGH), ECG tube current modulation (ETCM), and prospective gated axial (PGA) acquisitions. All emission images were corrected for photon attenuation using CT images obtained by default setting and an ultra-low dose CT (ULDCT) scan. Results: Radiation dose in RGH technique was 22.2{+-}4.0 mSv. It was reduced to 10.95{+-}0.82 and 4.13{+-}0.31 mSv using ETCM and PGA techniques, respectively. Radiation dose in CT transmission scan was reduced by 96.5% (from 4.53{+-}0.5 to 0.16{+-}0.01 mSv) when applying ULDCT as compared to the default CT. No significant difference in terms of image quality was found among various protocols. Conclusion: The proposed CT scanning strategies, i.e. ETCM or PGA for CTCA and ULDCT for PET attenuation correction, could reduce radiation dose up to 47% without degrading imaging quality in an integrated cardiac PET/CT coronary artery examination.

Rapid biosynthesis of silver nanoparticles using Crotalaria verrucosa leaves against the dengue vector Aedes aegypti: what happens around? An analysis of dragonfly predatory behaviour after exposure at ultra-low doses.

Science.gov (United States)

Murugan, Kadarkarai; Sanoopa, C P; Madhiyazhagan, Pari; Dinesh, Devakumar; Subramaniam, Jayapal; Panneerselvam, Chellasamy; Roni, Mathath; Suresh, Udaiyan; Nicoletti, Marcello; Alarfaj, Abdullah A; Munusamy, Murugan A; Higuchi, Akon; Kumar, Suresh; Perumalsamy, Haribalan; Ahn, Young-Joon; Benelli, Giovanni

2016-01-01

Aedes aegypti is a primary vector of dengue, a mosquito-borne viral disease infecting 50-100 million people every year. Here, we biosynthesised mosquitocidal silver nanoparticles (AgNP) using the aqueous leaf extract of Crotalaria verrucosa. The green synthesis of AgNP was studied by UV-vis spectroscopy, SEM, EDX and FTIR. C. verrucosa-synthesised AgNPs were toxic against A. aegypti larvae and pupae. LC50 of AgNP ranged from 3.496 ppm (I instar larvae) to 17.700 ppm (pupae). Furthermore, we evaluated the predatory efficiency of dragonfly nymphs, Brachydiplax sobrina, against II and III instar larvae of A. aegypti in an aquatic environment contaminated with ultra-low doses of AgNP. Under standard laboratory conditions, predation after 24 h was 87.5% (II) and 54.7% (III). In an AgNP-contaminated environment, predation was 91 and 75.5%, respectively. Overall, C. verrucosa-synthesised AgNP could be employed at ultra-low doses to reduce larval population of dengue vectors enhancing predation rates of dragonfly nymphs.

Reduced-dose C-arm computed tomography applications at a pediatric institution

Energy Technology Data Exchange (ETDEWEB)

Acord, Michael; Shellikeri, Sphoorti; Vatsky, Seth; Srinivasan, Abhay; Krishnamurthy, Ganesh; Keller, Marc S.; Cahill, Anne Marie [The Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States)

2017-12-15

Reduced-dose C-arm computed tomography (CT) uses flat-panel detectors to acquire real-time 3-D images in the interventional radiology suite to assist with anatomical localization and procedure planning. To describe dose-reduction techniques for C-arm CT at a pediatric institution and to provide guidance for implementation. We conducted a 5-year retrospective study on procedures using an institution-specific reduced-dose protocol: 5 or 8 s Dyna Rotation, 248/396 projection images/acquisition and 0.1-0.17 μGy/projection dose at the detector with 0.3/0.6/0.9-mm copper (Cu) filtration. We categorized cases by procedure type and average patient age and calculated C-arm CT and total dose area product (DAP). Two hundred twenty-two C-arm CT-guided procedures were performed with a dose-reduction protocol. The most common procedures were temporomandibular and sacroiliac joint injections (48.6%) and sclerotherapy (34.2%). C-arm CT was utilized in cases of difficult percutaneous access in less common applications such as cecostomy and gastrostomy placement, foreign body retrieval and thoracentesis. C-arm CT accounted for between 9.9% and 80.7% of the total procedural DAP. Dose-reducing techniques can preserve image quality for intervention while reducing radiation exposure to the child. This technology has multiple applications within pediatric interventional radiology and can be considered as an adjunctive imaging tool in a variety of procedures, particularly when percutaneous access is challenging despite routine fluoroscopic or ultrasound guidance. (orig.)

Biased motion vector interpolation for reduced video artifacts.

NARCIS (Netherlands)

2011-01-01

In a video processing system where motion vectors are estimated for a subset of the blocks of data forming a video frame, and motion vectors are interpolated for the remainder of the blocks of the frame, a method includes determining, for at least at least one block of the current frame for which a

Reducing dose calculation time for accurate iterative IMRT planning

International Nuclear Information System (INIS)

Siebers, Jeffrey V.; Lauterbach, Marc; Tong, Shidong; Wu Qiuwen; Mohan, Radhe

2002-01-01

A time-consuming component of IMRT optimization is the dose computation required in each iteration for the evaluation of the objective function. Accurate superposition/convolution (SC) and Monte Carlo (MC) dose calculations are currently considered too time-consuming for iterative IMRT dose calculation. Thus, fast, but less accurate algorithms such as pencil beam (PB) algorithms are typically used in most current IMRT systems. This paper describes two hybrid methods that utilize the speed of fast PB algorithms yet achieve the accuracy of optimizing based upon SC algorithms via the application of dose correction matrices. In one method, the ratio method, an infrequently computed voxel-by-voxel dose ratio matrix (R=D SC /D PB ) is applied for each beam to the dose distributions calculated with the PB method during the optimization. That is, D PB xR is used for the dose calculation during the optimization. The optimization proceeds until both the IMRT beam intensities and the dose correction ratio matrix converge. In the second method, the correction method, a periodically computed voxel-by-voxel correction matrix for each beam, defined to be the difference between the SC and PB dose computations, is used to correct PB dose distributions. To validate the methods, IMRT treatment plans developed with the hybrid methods are compared with those obtained when the SC algorithm is used for all optimization iterations and with those obtained when PB-based optimization is followed by SC-based optimization. In the 12 patient cases studied, no clinically significant differences exist in the final treatment plans developed with each of the dose computation methodologies. However, the number of time-consuming SC iterations is reduced from 6-32 for pure SC optimization to four or less for the ratio matrix method and five or less for the correction method. Because the PB algorithm is faster at computing dose, this reduces the inverse planning optimization time for our implementation

Design and simulation of MEMS vector hydrophone with reduced cross section based meander beams

Energy Technology Data Exchange (ETDEWEB)

Kumar, Manoj; Dutta, S.; Pal, Ramjay; Jain, K. K.; Gupta, Sudha; Bhan, R. K. [Solid State Physics Laboratory, DRDO, Lucknow Road, Timarpur, Delhi, India 110054 (India)

2016-04-13

MEMS based vector hydrophone is being one of the key device in the underwater communications. In this paper, we presented a bio-inspired MEMS vector hydrophone. The hydrophone structure consists of a proof mass suspended by four meander type beams with reduced cross-section. Modal patterns of the structure were studied. First three modal frequencies of the hydrophone structure were found to be 420 Hz, 420 Hz and 1646 Hz respectively. The deflection and stress of the hydrophone is found have linear behavior in the 1 µPa – 1Pa pressure range.

Reducing dose to the lungs through loosing target dose homogeneity requirement for radiotherapy of non small cell lung cancer.

Science.gov (United States)

Miao, Junjie; Yan, Hui; Tian, Yuan; Ma, Pan; Liu, Zhiqiang; Li, Minghui; Ren, Wenting; Chen, Jiayun; Zhang, Ye; Dai, Jianrong

2017-11-01

It is important to minimize lung dose during intensity-modulated radiation therapy (IMRT) of nonsmall cell lung cancer (NSCLC). In this study, an approach was proposed to reduce lung dose by relaxing the constraint of target dose homogeneity during treatment planning of IMRT. Ten NSCLC patients with lung tumor on the right side were selected. The total dose for planning target volume (PTV) was 60 Gy (2 Gy/fraction). For each patient, two IMRT plans with six beams were created in Pinnacle treatment planning system. The dose homogeneity of target was controlled by constraints on the maximum and uniform doses of target volume. One IMRT plan was made with homogeneous target dose (the resulting target dose was within 95%-107% of the prescribed dose), while another IMRT plan was made with inhomogeneous target dose (the resulting target dose was more than 95% of the prescribed dose). During plan optimization, the dose of cord and heart in two types of IMRT plans were kept nearly the same. The doses of lungs, PTV and organs at risk (OARs) between two types of IMRT plans were compared and analyzed quantitatively. For all patients, the lung dose was decreased in the IMRT plans with inhomogeneous target dose. On average, the mean dose, V5, V20, and V30 of lung were reduced by 1.4 Gy, 4.8%, 3.7%, and 1.7%, respectively, and the dose to normal tissue was also reduced. These reductions in DVH values were all statistically significant (P target dose could protect lungs better and may be considered as a choice for treating NSCLC. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

Reducing vector-borne disease by empowering farmers in integrated vector management

NARCIS (Netherlands)

Berg, van den H.; Hildebrand, von A.; Ragunathan, V.; Das, P.K.

2007-01-01

PROBLEM: Irrigated agriculture exposes rural people to health risks associated with vector-borne diseases and pesticides used in agriculture and for public health protection. Most developing countries lack collaboration between the agricultural and health sectors to jointly address these problems.

Novel high dose rate lip brachytherapy technique to improve dose homogeneity and reduce toxicity by customized mold

International Nuclear Information System (INIS)

Feldman, Jon; Appelbaum, Limor; Sela, Mordechay; Voskoboinik, Ninel; Kadouri, Sarit; Weinberger, Jeffrey; Orion, Itzhak; Meirovitz, Amichay

2014-01-01

The purpose of this study is to describe a novel brachytherapy technique for lip Squamous Cell Carcinoma, utilizing a customized mold with embedded brachytherapy sleeves, which separates the lip from the mandible, and improves dose homogeneity. Seven patients with T2 lip cancer treated with a “sandwich” technique of High Dose Rate (HDR) brachytherapy to the lip, consisting of interstitial catheters and a customized mold with embedded catheters, were reviewed for dosimetry and outcome using 3D planning. Dosimetric comparison was made between the “sandwich” technique to “classic” – interstitial catheters only plan. We compared dose volume histograms for Clinical Tumor Volume (CTV), normal tissue “hot spots” and mandible dose. We are reporting according to the ICRU 58 and calculated the Conformal Index (COIN) to show the advantage of our technique. The seven patients (ages 36–81 years, male) had median follow-up of 47 months. Four patients received Brachytherapy and External Beam Radiation Therapy, 3 patients received brachytherapy alone. All achieved local control, with excellent esthetic and functional results. All patients are disease free. The Customized Mold Sandwich technique (CMS) reduced the high dose region receiving 150% (V150) by an average of 20% (range 1–47%), The low dose region (les then 90% of the prescribed dose) improved by 73% in average by using the CMS technique. The COIN value for the CMS was in average 0.92 as opposed to 0.88 for the interstitial catheter only. All differences (excluding the low dose region) were statistically significant. The CMS technique significantly reduces the high dose volume and increases treatment homogeneity. This may reduce the potential toxicity to the lip and adjacent mandible, and results in excellent tumor control, cosmetic and functionality

The RED (reduce everyone's dose) initiative at Hinkley Point Power Station

International Nuclear Information System (INIS)

Weston, J.

1995-01-01

This paper does not offer a universal solution to reducing doses nor does it claim to introduce radically new ideas. It is a summarised account of the successes achieved in reducing the collective dose at a 30 year old power station. The key areas identified are the rewards of teamwork, the need to challenge established practices and the benefit of a dosimetry database. (author)

Method for dose-reduced 3D catheter tracking on a scanning-beam digital x-ray system using dynamic electronic collimation

Science.gov (United States)

Dunkerley, David A. P.; Funk, Tobias; Speidel, Michael A.

2016-03-01

Scanning-beam digital x-ray (SBDX) is an inverse geometry x-ray fluoroscopy system capable of tomosynthesis-based 3D catheter tracking. This work proposes a method of dose-reduced 3D tracking using dynamic electronic collimation (DEC) of the SBDX scanning x-ray tube. Positions in the 2D focal spot array are selectively activated to create a regionof- interest (ROI) x-ray field around the tracked catheter. The ROI position is updated for each frame based on a motion vector calculated from the two most recent 3D tracking results. The technique was evaluated with SBDX data acquired as a catheter tip inside a chest phantom was pulled along a 3D trajectory. DEC scans were retrospectively generated from the detector images stored for each focal spot position. DEC imaging of a catheter tip in a volume measuring 11.4 cm across at isocenter required 340 active focal spots per frame, versus 4473 spots in full-FOV mode. The dose-area-product (DAP) and peak skin dose (PSD) for DEC versus full field-of-view (FOV) scanning were calculated using an SBDX Monte Carlo simulation code. DAP was reduced to 7.4% to 8.4% of the full-FOV value, consistent with the relative number of active focal spots (7.6%). For image sequences with a moving catheter, PSD was 33.6% to 34.8% of the full-FOV value. The root-mean-squared-deviation between DEC-based 3D tracking coordinates and full-FOV 3D tracking coordinates was less than 0.1 mm. The 3D distance between the tracked tip and the sheath centerline averaged 0.75 mm. Dynamic electronic collimation can reduce dose with minimal change in tracking performance.

Multiscale benchmarking of drug delivery vectors.

Science.gov (United States)

Summers, Huw D; Ware, Matthew J; Majithia, Ravish; Meissner, Kenith E; Godin, Biana; Rees, Paul

2016-10-01

Cross-system comparisons of drug delivery vectors are essential to ensure optimal design. An in-vitro experimental protocol is presented that separates the role of the delivery vector from that of its cargo in determining the cell response, thus allowing quantitative comparison of different systems. The technique is validated through benchmarking of the dose-response of human fibroblast cells exposed to the cationic molecule, polyethylene imine (PEI); delivered as a free molecule and as a cargo on the surface of CdSe nanoparticles and Silica microparticles. The exposure metrics are converted to a delivered dose with the transport properties of the different scale systems characterized by a delivery time, τ. The benchmarking highlights an agglomeration of the free PEI molecules into micron sized clusters and identifies the metric determining cell death as the total number of PEI molecules presented to cells, determined by the delivery vector dose and the surface density of the cargo. Copyright © 2016 Elsevier Inc. All rights reserved.

The effect on dose accumulation accuracy of inverse-consistency and transitivity error reduced deformation maps

International Nuclear Information System (INIS)

Hardcastle, Nicholas; Bender, Edward T.; Tomé, Wolfgang A.

2014-01-01

It has previously been shown that deformable image registrations (DIRs) often result in deformation maps that are neither inverse-consistent nor transitive, and that the dose accumulation based on these deformation maps can be inconsistent if different image pathways are used for dose accumulation. A method presented to reduce inverse consistency and transitivity errors has been shown to result in more consistent dose accumulation, regardless of the image pathway selected for dose accumulation. The present study investigates the effect on the dose accumulation accuracy of deformation maps processed to reduce inverse consistency and transitivity errors. A set of lung 4DCT phases were analysed, consisting of four images on which a dose grid was created. Dose to 75 corresponding anatomical locations was manually tracked. Dose accumulation was performed between all image sets with Demons derived deformation maps as well as deformation maps processed to reduce inverse consistency and transitivity errors. The ground truth accumulated dose was then compared with the accumulated dose derived from DIR. Two dose accumulation image pathways were considered. The post-processing method to reduce inverse consistency and transitivity errors had minimal effect on the dose accumulation accuracy. There was a statistically significant improvement in dose accumulation accuracy for one pathway, but for the other pathway there was no statistically significant difference. A post-processing technique to reduce inverse consistency and transitivity errors has a positive, yet minimal effect on the dose accumulation accuracy. Thus the post-processing technique improves consistency of dose accumulation with minimal effect on dose accumulation accuracy.

Hepatorenal correction in murine glycogen storage disease type I with a double-stranded adeno-associated virus vector.

LENUS (Irish Health Repository)

Luo, Xiaoyan

2011-11-01

Glycogen storage disease type Ia (GSD-Ia) is caused by the deficiency of glucose-6-phosphatase (G6Pase). Long-term complications of GSD-Ia include life-threatening hypoglycemia and proteinuria progressing to renal failure. A double-stranded (ds) adeno-associated virus serotype 2 (AAV2) vector encoding human G6Pase was pseudotyped with four serotypes, AAV2, AAV7, AAV8, and AAV9, and we evaluated efficacy in 12-day-old G6pase (-\\/-) mice. Hypoglycemia during fasting (plasma glucose <100 mg\\/dl) was prevented for >6 months by the dsAAV2\\/7, dsAAV2\\/8, and dsAAV2\\/9 vectors. Prolonged fasting for 8 hours revealed normalization of blood glucose following dsAAV2\\/9 vector administration at the higher dose. The glycogen content of kidney was reduced by >65% with both the dsAAV2\\/7 and dsAAV2\\/9 vectors, and renal glycogen content was stably reduced between 7 and 12 months of age for the dsAAV2\\/9 vector-treated mice. Every vector-treated group had significantly reduced glycogen content in the liver, in comparison with untreated G6pase (-\\/-) mice. G6Pase was expressed in many renal epithelial cells of with the dsAAV2\\/9 vector for up to 12 months. Albuminuria and renal fibrosis were reduced by the dsAAV2\\/9 vector. Hepatorenal correction in G6pase (-\\/-) mice demonstrates the potential of AAV vectors for the correction of inherited diseases of metabolism.

A reduce and replace strategy for suppressing vector-borne diseases: insights from a stochastic, spatial model.

Directory of Open Access Journals (Sweden)

Kenichi W Okamoto

Full Text Available Two basic strategies have been proposed for using transgenic Aedes aegypti mosquitoes to decrease dengue virus transmission: population reduction and population replacement. Here we model releases of a strain of Ae. aegypti carrying both a gene causing conditional adult female mortality and a gene blocking virus transmission into a wild population to assess whether such releases could reduce the number of competent vectors. We find this "reduce and replace" strategy can decrease the frequency of competent vectors below 50% two years after releases end. Therefore, this combined approach appears preferable to releasing a strain carrying only a female-killing gene, which is likely to merely result in temporary population suppression. However, the fixation of anti-pathogen genes in the population is unlikely. Genetic drift at small population sizes and the spatially heterogeneous nature of the population recovery after releases end prevent complete replacement of the competent vector population. Furthermore, releasing more individuals can be counter-productive in the face of immigration by wild-type mosquitoes, as greater population reduction amplifies the impact wild-type migrants have on the long-term frequency of the anti-pathogen gene. We expect the results presented here to give pause to expectations for driving an anti-pathogen construct to fixation by relying on releasing individuals carrying this two-gene construct. Nevertheless, in some dengue-endemic environments, a spatially heterogeneous decrease in competent vectors may still facilitate decreasing disease incidence.

DuraSeal® as a spacer to reduce rectal doses in low-dose rate brachytherapy for prostate cancer

International Nuclear Information System (INIS)

Heikkilä, Vesa-Pekka; Kärnä, Aarno; Vaarala, Markku H.

2014-01-01

The purpose of this study was to evaluate the utility of off-label use of DuraSeal® polyethylene glycol (PEG) gel in low-dose rate (LDR) prostate brachytherapy seed implantation to reduce rectal doses. Diluted DuraSeal® was easy to use and, in spite of a clearance effect, useful in decreasing D 2cc rectal doses

Low dose irradiation reduces cancer mortality rates

International Nuclear Information System (INIS)

Luckey, T.D.

2000-01-01

Low doses of ionizing radiation stimulate development, growth, memory, sensual acuity, fecundity, and immunity (Luckey, T.D., ''Radiation Hormesis'', CRC Press, 1991). Increased immune competence reduces cancer mortality rates and provides increased average lifespan in animals. Decreased cancer mortality rates in atom bomb victims who received low dose irradiation makes it desirable to examine populations exposed to low dose irradiation. Studies with over 300,000 workers and 7 million person-years provide a valid comparison of radiation exposed and control unclear workers (Luckey, T.D., Nurture with Ionizing Radiation, Nutrition and Cancer, 34:1-11, 1999). Careful selection of controls eliminated any ''healthy worker effect''. The person-year corrected average indicated the cancer mortality rate of exposed workers was only 51% that of control workers. Lung cancer mortality rates showed a highly significant negative correlation with radon concentrations in 272,000 U.S. homes (Cohen, B.L., Health Physics 68:157-174, 1995). In contrast, radon concentrations showed no effect on lung cancer rates in miners from different countries (Lubin, J.H. Am. J. Epidemiology 140:323-332, 1994). This provides evidence that excessive lung cancer in miners is caused by particulates (the major factor) or toxic gases. The relative risk for cancer mortality was 3.7% in 10,000 Taiwanese exposed to low level of radiation from 60 Co in their steel supported homes (Luan, Y.C. et al., Am. Nuclear Soc. Trans. Boston, 1999). This remarkable finding needs further study. A major mechanism for reduced cancer mortality rates is increased immune competence; this includes both cell and humoral components. Low dose irradiation increases circulating lymphocytes. Macrophage and ''natural killer'' cells can destroy altered (cancer) cells before the mass becomes too large. Low dose irradiation also kills suppressor T-cells; this allows helper T-cells to activate killer cells and antibody producing cells

Elimination of contaminating cap genes in AAV vector virions reduces immune responses and improves transgene expression in a canine gene therapy model.

Science.gov (United States)

Wang, Z; Halbert, C L; Lee, D; Butts, T; Tapscott, S J; Storb, R; Miller, A D

2014-04-01

Animal and human gene therapy studies utilizing AAV vectors have shown that immune responses to AAV capsid proteins can severely limit transgene expression. The main source of capsid antigen is that associated with the AAV vectors, which can be reduced by stringent vector purification. A second source of AAV capsid proteins is that expressed from cap genes aberrantly packaged into AAV virions during vector production. This antigen source can be eliminated by the use of a cap gene that is too large to be incorporated into an AAV capsid, such as a cap gene containing a large intron (captron gene). Here, we investigated the effects of elimination of cap gene transfer and of vector purification by CsCl gradient centrifugation on AAV vector immunogenicity and expression following intramuscular injection in dogs. We found that both approaches reduced vector immunogenicity and that combining the two produced the lowest immune responses and highest transgene expression. This combined approach enabled the use of a relatively mild immunosuppressive regimen to promote robust micro-dystrophin gene expression in Duchenne muscular dystrophy-affected dogs. Our study shows the importance of minimizing AAV cap gene impurities and indicates that this improvement in AAV vector production may benefit human applications.

Nephele: genotyping via complete composition vectors and MapReduce

Directory of Open Access Journals (Sweden)

Mardis Scott

2011-08-01

Full Text Available Abstract Background Current sequencing technology makes it practical to sequence many samples of a given organism, raising new challenges for the processing and interpretation of large genomics data sets with associated metadata. Traditional computational phylogenetic methods are ideal for studying the evolution of gene/protein families and using those to infer the evolution of an organism, but are less than ideal for the study of the whole organism mainly due to the presence of insertions/deletions/rearrangements. These methods provide the researcher with the ability to group a set of samples into distinct genotypic groups based on sequence similarity, which can then be associated with metadata, such as host information, pathogenicity, and time or location of occurrence. Genotyping is critical to understanding, at a genomic level, the origin and spread of infectious diseases. Increasingly, genotyping is coming into use for disease surveillance activities, as well as for microbial forensics. The classic genotyping approach has been based on phylogenetic analysis, starting with a multiple sequence alignment. Genotypes are then established by expert examination of phylogenetic trees. However, these traditional single-processor methods are suboptimal for rapidly growing sequence datasets being generated by next-generation DNA sequencing machines, because they increase in computational complexity quickly with the number of sequences. Results Nephele is a suite of tools that uses the complete composition vector algorithm to represent each sequence in the dataset as a vector derived from its constituent k-mers by passing the need for multiple sequence alignment, and affinity propagation clustering to group the sequences into genotypes based on a distance measure over the vectors. Our methods produce results that correlate well with expert-defined clades or genotypes, at a fraction of the computational cost of traditional phylogenetic methods run on

Reducing ionizing radiation doses during cardiac interventions in pregnant women.

Science.gov (United States)

Orchard, Elizabeth; Dix, Sarah; Wilson, Neil; Mackillop, Lucy; Ormerod, Oliver

2012-09-01

There is concern over ionizing radiation exposure in women who are pregnant or of child-bearing age. Due to the increasing prevalence of congenital and acquired heart disease, the number of women who require cardiac interventions during pregnancy has increased. We have developed protocols for cardiac interventions in pregnant women and women of child-bearing age, aimed at substantially reducing both fluoroscopy duration and radiation doses. Over five years, we performed cardiac interventions on 15 pregnant women, nine postpartum women and four as part of prepregnancy assessment. Fluoroscopy times were minimized by simultaneous use of intracardiac echocardiography, and by using very low frame rates (2/second) during fluoroscopy. The procedures most commonly undertaken were closure of atrial septal defect (ASD) or patent foramen ovale (PFO) in 16 women, coronary angiograms in seven, right and left heart catheters in three and two stent placements. The mean screening time for all patients was 2.38 minutes (range 0.48-13.7), the median radiation dose was 66 (8.9-1501) Gy/cm(2). The median radiation dose to uterus was 1.92 (0.59-5.47) μGy, and the patient estimated dose was 0.24 (0.095-0.80) mSv. Ionizing radiation can be used safely in the management of severe cardiac structural disease in pregnancy, with very low ionizing radiation dose to the mother and extremely low exposure to the fetus. With experience, ionizing radiation doses at our institution have been reduced.

HALF-DOSE DEPOT TRIPTORELIN COMPARABLE TO REDUCED DAILY BUSERELIN: A RANDOMIZED CLINICAL TRIAL

Directory of Open Access Journals (Sweden)

L. Safdarian

2007-09-01

Full Text Available Pituitary suppression by depot GnRH agonist may be excessive for ovarian stimulation. This study compares the efficacy of a single half-dose depot triptorelin and reduced-dose daily buserelin in a long protocol ICSI/ET. METHODS: A total of 182 patients were randomized into two groups using sealed envelopes. Pituitary desensitization was obtained in group 1 (91 patients with half-dose (1.87 mg depot triptorelin in the mid-luteal phase of their menstrual cycle, and in group 2 (91 patients with standard daily dose (0.5 mg buserelin, which was then reduced to 0.25 mg at the start of human menopausal gonadotropin (HMG stimulation. RESULTS: No significant differences were found among those who received HCG in terms of clinical pregnancy rate (34.4% in both groups, implantation rate (14.8% in group 1 versus 11.1% in group 2, fertilization rate (93.3 versus 95.6%, poor response rate (11.1 versus 6.7%, and miscarriage rate (11.1 versus 7.8%. No significant differences were seen in number of HMG ampoules used, follicles at HCG administration, and oocytes retrieved. The number of days of stimulation was significantly reduced in group 2 (11.2 +/- 1.8 in group 1 versus 10.6 +/- 1.9, p = 0.030. CONCLUSION: A half-dose of depot triptorelin can be successfully used in ovarian stimulation instead of reduced-dose daily buserelin, with more patient comfort and reduced stress and cost of injections.

New technologies to reduce pediatric radiation doses

International Nuclear Information System (INIS)

Bernhardt, Philipp; Lendl, Markus; Deinzer, Frank

2006-01-01

X-ray dose reduction in pediatrics is particularly important because babies and children are very sensitive to radiation exposure. We present new developments to further decrease pediatric patient dose. With the help of an advanced exposure control, a constant image quality can be maintained for all patient sizes, leading to dose savings for babies and children of up to 30%. Because objects of interest are quite small and the speed of motion is high in pediatric patients, short pulse widths down to 4 ms are important to reduce motion blurring artifacts. Further, a new noise-reduction algorithm is presented that detects and processes signal and noise in different frequency bands, generating smooth images without contrast loss. Finally, we introduce a super-resolution technique: two or more medical images, which are shifted against each other in a subpixel region, are combined to resolve structures smaller than the size of a single pixel. Advanced exposure control, short exposure times, noise reduction and super-resolution provide improved image quality, which can also be invested to save radiation exposure. All in all, the tools presented here offer a large potential to minimize the deterministic and stochastic risks of radiation exposure. (orig.)

Reducing radiation dose to the female breast during conventional and dedicated breast computed tomography

Science.gov (United States)

Rupcich, Franco John

The purpose of this study was to quantify the effectiveness of techniques intended to reduce dose to the breast during CT coronary angiography (CTCA) scans with respect to task-based image quality, and to evaluate the effectiveness of optimal energy weighting in improving contrast-to-noise ratio (CNR), and thus the potential for reducing breast dose, during energy-resolved dedicated breast CT. A database quantifying organ dose for several radiosensitive organs irradiated during CTCA, including the breast, was generated using Monte Carlo simulations. This database facilitates estimation of organ-specific dose deposited during CTCA protocols using arbitrary x-ray spectra or tube-current modulation schemes without the need to run Monte Carlo simulations. The database was used to estimate breast dose for simulated CT images acquired for a reference protocol and five protocols intended to reduce breast dose. For each protocol, the performance of two tasks (detection of signals with unknown locations) was compared over a range of breast dose levels using a task-based, signal-detectability metric: the estimator of the area under the exponential free-response relative operating characteristic curve, AFE. For large-diameter/medium-contrast signals, when maintaining equivalent AFE, the 80 kV partial, 80 kV, 120 kV partial, and 120 kV tube-current modulated protocols reduced breast dose by 85%, 81%, 18%, and 6%, respectively, while the shielded protocol increased breast dose by 68%. Results for the small-diameter/high-contrast signal followed similar trends, but with smaller magnitude of the percent changes in dose. The 80 kV protocols demonstrated the greatest reduction to breast dose, however, the subsequent increase in noise may be clinically unacceptable. Tube output for these protocols can be adjusted to achieve more desirable noise levels with lesser dose reduction. The improvement in CNR of optimally projection-based and image-based weighted images relative to photon

Reducing radiation doses to the breast, thyroid and gonads during diagnostic radiography

International Nuclear Information System (INIS)

Weatherburn, G.C.

1983-01-01

The skin entry and exit doses on patients undergoing routine radiographic examinations of areas in which the breast, thyroid and gonads are included in the primary beam were measured using thermoluminescent dosimeters. To obtain further information about patient doses, measurements were also made on a phantom at similar skin positions and at the positions of these organs. Comparisons of the doses to these radiosensitive organs were made for the antero-posterior and postero-anterior projections. In cases where it was found that the doses were reduced by the use of non-conventional relationship between the relative positions of the patient and the film, suggestions are made for the adaptations which would have to be made to X-ray equipment to enable these projections to be taken routinely. Other techniques, such as air gap techniques and thyroid shielding, whereby patient doses can be reduced during routine radiography are also examined. Finally the implications of these results for radiation protection of patients are considered. (author)

Deep learning enables reduced gadolinium dose for contrast-enhanced brain MRI.

Science.gov (United States)

Gong, Enhao; Pauly, John M; Wintermark, Max; Zaharchuk, Greg

2018-02-13

There are concerns over gadolinium deposition from gadolinium-based contrast agents (GBCA) administration. To reduce gadolinium dose in contrast-enhanced brain MRI using a deep learning method. Retrospective, crossover. Sixty patients receiving clinically indicated contrast-enhanced brain MRI. 3D T 1 -weighted inversion-recovery prepped fast-spoiled-gradient-echo (IR-FSPGR) imaging was acquired at both 1.5T and 3T. In 60 brain MRI exams, the IR-FSPGR sequence was obtained under three conditions: precontrast, postcontrast images with 10% low-dose (0.01mmol/kg) and 100% full-dose (0.1 mmol/kg) of gadobenate dimeglumine. We trained a deep learning model using the first 10 cases (with mixed indications) to approximate full-dose images from the precontrast and low-dose images. Synthesized full-dose images were created using the trained model in two test sets: 20 patients with mixed indications and 30 patients with glioma. For both test sets, low-dose, true full-dose, and the synthesized full-dose postcontrast image sets were compared quantitatively using peak-signal-to-noise-ratios (PSNR) and structural-similarity-index (SSIM). For the test set comprised of 20 patients with mixed indications, two neuroradiologists scored blindly and independently for the three postcontrast image sets, evaluating image quality, motion-artifact suppression, and contrast enhancement compared with precontrast images. Results were assessed using paired t-tests and noninferiority tests. The proposed deep learning method yielded significant (n = 50, P 5 dB PSNR gains and >11.0% SSIM). Ratings on image quality (n = 20, P = 0.003) and contrast enhancement (n = 20, P deep learning method, gadolinium dose can be reduced 10-fold while preserving contrast information and avoiding significant image quality degradation. 3 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2018. © 2018 International Society for Magnetic Resonance in Medicine.

Reducing radiation doses to the breast, thyroid and gonads during diagnostic radiography

International Nuclear Information System (INIS)

Weatherburn, G.C.

1983-01-01

The measurement of doses to the gonads during radiography of the pelvis is discussed. Phantom measurements to estimate doses to the ovaries in antero-posterior (AP) and postero-anterior (PA) projections of the pelvis showed that the dose is 15% of the skin entry dose in the AP projection and 9% in the PA projection. The air gap technique and its applications in reducing radiation doses to the gonads, breast and thyroid is described. A summary of dose reduction factors for these radiosensitive organs achieved by modified radiographic techniques in radiography of the chest, pelvis, spine and skull is given. (U.K.)

Effects of West Nile virus dose and extrinsic incubation temperature on temporal progression of vector competence in Culex pipiens quinquefasciatus.

Science.gov (United States)

Anderson, Sheri L; Richards, Stephanie L; Tabachnick, Walter J; Smartt, Chelsea T

2010-03-01

Culex pipiens quinquefasciatus were fed blood containing either 7.0 +/- 0.1 logs plaque-forming units (pfu)/ml (high dose) or 5.9 +/- 0.1 logs pfu/ml (low dose) of West Nile virus and held at extrinsic incubation temperatures (EIT) of 28 degrees C or 25 degrees C. Approximately 20 mosquitoes per dose were collected after incubation periods (IP) of 4, 6, 8, and 12 days postinfection (dpi). Infection rates were influenced by EIT and virus dose but not by IP. Body titer was significantly higher for mosquitoes fed the high dose and held at 28 degrees C at the later IPs (6, 8, and 12 dpi). However, leg titer was significantly higher for mosquitoes at the later IPs but did not differ between EITs or doses. Because infection rates varied with EIT and dose, there is likely a midgut infection barrier influenced by these factors that is not influenced by IP. Dissemination rates were influenced by all 3 factors consistent with the presence of a midgut escape barrier. Dissemination rate, body titer, and leg titer were dependent on IP, indicating the need to investigate multiple time points in vector competence studies to elucidate critical events in infection and dissemination.

WE-AB-207A-06: Progressive Dose Control for Cone Beam CT with Deformation Assisted Temporal Nonlocal Means Method

International Nuclear Information System (INIS)

Chen, L; Shen, C; Wang, J; Jiang, S; Jia, X

2016-01-01

Purpose: To reduce cone beam CT (CBCT) imaging dose, we previously proposed a progressive dose control (PDC) scheme to employ temporal correlation between CBCT images at different fractions for image quality enhancement. A temporal non-local means (TNLM) method was developed to enhance quality of a new low-dose CBCT using existing high-quality CBCT. To enhance a voxel value, the TNLM method searches for similar voxels in a window. Due to patient deformation among the two CBCTs, a large searching window was required, reducing image quality and computational efficiency. This abstract proposes a deformation-assisted TNLM (DA-TNLM) method to solve this problem. Methods: For a low-dose CBCT to be enhanced using a high-quality CBCT, we first performed deformable image registration between the low-dose CBCT and the high-quality CBCT to approximately establish voxel correspondence between the two. A searching window for a voxel was then set based on the deformation vector field. Specifically, the search window for each voxel was shifted by the deformation vector. A TNLM step was then applied using only voxels within this determined window to correct image intensity at the low-dose CBCT. Results: We have tested the proposed scheme on simulated CIRS phantom data and real patient data. The CITS phantom was scanned on Varian onboard imaging CBCT system with coach shifting and dose reducing for each time. The real patient data was acquired in four fractions with dose reduced from standard CBCT dose to 12.5% of standard dose. It was found that the DA-TNLM method can reduce total dose by over 75% on average in the first four fractions. Conclusion: We have developed a PDC scheme which can enhance the quality of image scanned at low dose using a DA-TNLM method. Tests in phantom and patient studies demonstrated promising results.

Approaches to reducing photon dose calculation errors near metal implants

Energy Technology Data Exchange (ETDEWEB)

Huang, Jessie Y.; Followill, David S.; Howell, Rebecca M.; Mirkovic, Dragan; Kry, Stephen F., E-mail: sfkry@mdanderson.org [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 and Graduate School of Biomedical Sciences, The University of Texas Health Science Center Houston, Houston, Texas 77030 (United States); Liu, Xinming [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 and Graduate School of Biomedical Sciences, The University of Texas Health Science Center Houston, Houston, Texas 77030 (United States); Stingo, Francesco C. [Department of Biostatistics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 and Graduate School of Biomedical Sciences, The University of Texas Health Science Center Houston, Houston, Texas 77030 (United States)

2016-09-15

Purpose: Dose calculation errors near metal implants are caused by limitations of the dose calculation algorithm in modeling tissue/metal interface effects as well as density assignment errors caused by imaging artifacts. The purpose of this study was to investigate two strategies for reducing dose calculation errors near metal implants: implementation of metal-based energy deposition kernels in the convolution/superposition (C/S) dose calculation method and use of metal artifact reduction methods for computed tomography (CT) imaging. Methods: Both error reduction strategies were investigated using a simple geometric slab phantom with a rectangular metal insert (composed of titanium or Cerrobend), as well as two anthropomorphic phantoms (one with spinal hardware and one with dental fillings), designed to mimic relevant clinical scenarios. To assess the dosimetric impact of metal kernels, the authors implemented titanium and silver kernels in a commercial collapsed cone C/S algorithm. To assess the impact of CT metal artifact reduction methods, the authors performed dose calculations using baseline imaging techniques (uncorrected 120 kVp imaging) and three commercial metal artifact reduction methods: Philips Healthcare’s O-MAR, GE Healthcare’s monochromatic gemstone spectral imaging (GSI) using dual-energy CT, and GSI with metal artifact reduction software (MARS) applied. For the simple geometric phantom, radiochromic film was used to measure dose upstream and downstream of metal inserts. For the anthropomorphic phantoms, ion chambers and radiochromic film were used to quantify the benefit of the error reduction strategies. Results: Metal kernels did not universally improve accuracy but rather resulted in better accuracy upstream of metal implants and decreased accuracy directly downstream. For the clinical cases (spinal hardware and dental fillings), metal kernels had very little impact on the dose calculation accuracy (<1.0%). Of the commercial CT artifact

Approaches to reducing photon dose calculation errors near metal implants

International Nuclear Information System (INIS)

Huang, Jessie Y.; Followill, David S.; Howell, Rebecca M.; Mirkovic, Dragan; Kry, Stephen F.; Liu, Xinming; Stingo, Francesco C.

2016-01-01

Purpose: Dose calculation errors near metal implants are caused by limitations of the dose calculation algorithm in modeling tissue/metal interface effects as well as density assignment errors caused by imaging artifacts. The purpose of this study was to investigate two strategies for reducing dose calculation errors near metal implants: implementation of metal-based energy deposition kernels in the convolution/superposition (C/S) dose calculation method and use of metal artifact reduction methods for computed tomography (CT) imaging. Methods: Both error reduction strategies were investigated using a simple geometric slab phantom with a rectangular metal insert (composed of titanium or Cerrobend), as well as two anthropomorphic phantoms (one with spinal hardware and one with dental fillings), designed to mimic relevant clinical scenarios. To assess the dosimetric impact of metal kernels, the authors implemented titanium and silver kernels in a commercial collapsed cone C/S algorithm. To assess the impact of CT metal artifact reduction methods, the authors performed dose calculations using baseline imaging techniques (uncorrected 120 kVp imaging) and three commercial metal artifact reduction methods: Philips Healthcare’s O-MAR, GE Healthcare’s monochromatic gemstone spectral imaging (GSI) using dual-energy CT, and GSI with metal artifact reduction software (MARS) applied. For the simple geometric phantom, radiochromic film was used to measure dose upstream and downstream of metal inserts. For the anthropomorphic phantoms, ion chambers and radiochromic film were used to quantify the benefit of the error reduction strategies. Results: Metal kernels did not universally improve accuracy but rather resulted in better accuracy upstream of metal implants and decreased accuracy directly downstream. For the clinical cases (spinal hardware and dental fillings), metal kernels had very little impact on the dose calculation accuracy (<1.0%). Of the commercial CT artifact

Vector-model-supported approach in prostate plan optimization

International Nuclear Information System (INIS)

Liu, Eva Sau Fan; Wu, Vincent Wing Cheung; Harris, Benjamin; Lehman, Margot; Pryor, David; Chan, Lawrence Wing Chi

2017-01-01

Lengthy time consumed in traditional manual plan optimization can limit the use of step-and-shoot intensity-modulated radiotherapy/volumetric-modulated radiotherapy (S&S IMRT/VMAT). A vector model base, retrieving similar radiotherapy cases, was developed with respect to the structural and physiologic features extracted from the Digital Imaging and Communications in Medicine (DICOM) files. Planning parameters were retrieved from the selected similar reference case and applied to the test case to bypass the gradual adjustment of planning parameters. Therefore, the planning time spent on the traditional trial-and-error manual optimization approach in the beginning of optimization could be reduced. Each S&S IMRT/VMAT prostate reference database comprised 100 previously treated cases. Prostate cases were replanned with both traditional optimization and vector-model-supported optimization based on the oncologists' clinical dose prescriptions. A total of 360 plans, which consisted of 30 cases of S&S IMRT, 30 cases of 1-arc VMAT, and 30 cases of 2-arc VMAT plans including first optimization and final optimization with/without vector-model-supported optimization, were compared using the 2-sided t-test and paired Wilcoxon signed rank test, with a significance level of 0.05 and a false discovery rate of less than 0.05. For S&S IMRT, 1-arc VMAT, and 2-arc VMAT prostate plans, there was a significant reduction in the planning time and iteration with vector-model-supported optimization by almost 50%. When the first optimization plans were compared, 2-arc VMAT prostate plans had better plan quality than 1-arc VMAT plans. The volume receiving 35 Gy in the femoral head for 2-arc VMAT plans was reduced with the vector-model-supported optimization compared with the traditional manual optimization approach. Otherwise, the quality of plans from both approaches was comparable. Vector-model-supported optimization was shown to offer much shortened planning time and iteration

Vector-model-supported approach in prostate plan optimization

Energy Technology Data Exchange (ETDEWEB)

Liu, Eva Sau Fan [Department of Radiation Oncology, Princess Alexandra Hospital, Brisbane (Australia); Department of Health Technology and Informatics, The Hong Kong Polytechnic University (Hong Kong); Wu, Vincent Wing Cheung [Department of Health Technology and Informatics, The Hong Kong Polytechnic University (Hong Kong); Harris, Benjamin [Department of Radiation Oncology, Princess Alexandra Hospital, Brisbane (Australia); Lehman, Margot; Pryor, David [Department of Radiation Oncology, Princess Alexandra Hospital, Brisbane (Australia); School of Medicine, University of Queensland (Australia); Chan, Lawrence Wing Chi, E-mail: wing.chi.chan@polyu.edu.hk [Department of Health Technology and Informatics, The Hong Kong Polytechnic University (Hong Kong)

2017-07-01

Lengthy time consumed in traditional manual plan optimization can limit the use of step-and-shoot intensity-modulated radiotherapy/volumetric-modulated radiotherapy (S&S IMRT/VMAT). A vector model base, retrieving similar radiotherapy cases, was developed with respect to the structural and physiologic features extracted from the Digital Imaging and Communications in Medicine (DICOM) files. Planning parameters were retrieved from the selected similar reference case and applied to the test case to bypass the gradual adjustment of planning parameters. Therefore, the planning time spent on the traditional trial-and-error manual optimization approach in the beginning of optimization could be reduced. Each S&S IMRT/VMAT prostate reference database comprised 100 previously treated cases. Prostate cases were replanned with both traditional optimization and vector-model-supported optimization based on the oncologists' clinical dose prescriptions. A total of 360 plans, which consisted of 30 cases of S&S IMRT, 30 cases of 1-arc VMAT, and 30 cases of 2-arc VMAT plans including first optimization and final optimization with/without vector-model-supported optimization, were compared using the 2-sided t-test and paired Wilcoxon signed rank test, with a significance level of 0.05 and a false discovery rate of less than 0.05. For S&S IMRT, 1-arc VMAT, and 2-arc VMAT prostate plans, there was a significant reduction in the planning time and iteration with vector-model-supported optimization by almost 50%. When the first optimization plans were compared, 2-arc VMAT prostate plans had better plan quality than 1-arc VMAT plans. The volume receiving 35 Gy in the femoral head for 2-arc VMAT plans was reduced with the vector-model-supported optimization compared with the traditional manual optimization approach. Otherwise, the quality of plans from both approaches was comparable. Vector-model-supported optimization was shown to offer much shortened planning time and iteration

Treatment Planning for Pulsed Reduced Dose-Rate Radiotherapy in Helical Tomotherapy

International Nuclear Information System (INIS)

Rong Yi; Paliwal, Bhudatt; Howard, Steven P.; Welsh, James

2011-01-01

Purpose: Pulsed reduced dose-rate radiotherapy (PRDR) is a valuable method of reirradiation because of its potential to reduce late normal tissue toxicity while still yielding significant tumoricidal effect. A typical method using a conventional linear accelerator (linac) is to deliver a series of 20-cGy pulses separated by 3-min intervals to give an effective dose-rate of just under 7 cGy/min. Such a strategy is fraught with difficulties when attempted on a helical tomotherapy unit. We investigated various means to overcome this limitation. Methods and Materials: Phantom and patient cases were studied. Plans were generated with varying combinations of field width (FW), pitch, and modulation factor (MF) to administer 200 cGy per fraction to the planning target in eight subfractions, thereby mimicking the technique used on conventional linacs. Plans were compared using dose-volume histograms, homogeneity indices, conformation numbers, and treatment time. Plan delivery quality assurance was performed to assess deliverability. Results: It was observed that for helical tomotherapy, intrinsic limitations in leaf open time in the multileaf collimator deteriorate plan quality and deliverability substantially when attempting to deliver very low doses such as 20-40 cGy. The various permutations evaluated revealed that the combination of small FW (1.0 cm), small MF (1.3-1.5), and large pitch (∼0.86), along with the half-gantry-angle-blocked scheme, can generate clinically acceptable plans with acceptable delivery accuracy (±3%). Conclusion: Pulsed reduced dose-rate radiotherapy can be accurately delivered using helical tomotherapy for tumor reirradiation when the appropriate combination of FW, MF, and pitch is used.

Increased tumor localization and reduced immune response to adenoviral vector formulated with the liposome DDAB/DOPE.

Science.gov (United States)

Steel, Jason C; Cavanagh, Heather M A; Burton, Mark A; Abu-Asab, Mones S; Tsokos, Maria; Morris, John C; Kalle, Wouter H J

2007-04-01

We aimed to increase the efficiency of adenoviral vectors by limiting adenoviral spread from the target site and reducing unwanted host immune responses to the vector. We complexed adenoviral vectors with DDAB-DOPE liposomes to form adenovirus-liposomal (AL) complexes. AL complexes were delivered by intratumoral injection in an immunocompetent subcutaneous rat tumor model and the immunogenicity of the AL complexes and the expression efficiency in the tumor and other organs was examined. Animals treated with the AL complexes had significantly lower levels of beta-galactosidase expression in systemic tissues compared to animals treated with the naked adenovirus (NA) (P<0.05). The tumor to non-tumor ratio of beta-galactosidase marker expression was significantly higher for the AL complex treated animals. NA induced significantly higher titers of adenoviral-specific antibodies compared to the AL complexes (P<0.05). The AL complexes provided protection (immunoshielding) to the adenovirus from neutralizing antibody. Forty-seven percent more beta-galactosidase expression was detected following intratumoral injection with AL complexes compared to the NA in animals pre-immunized with adenovirus. Complexing of adenovirus with liposomes provides a simple method to enhance tumor localization of the vector, decrease the immunogenicity of adenovirus, and provide protection of the virus from pre-existing neutralizing antibodies.

Study on the method or reducing the operator's exposure dose from a C-Arm system

International Nuclear Information System (INIS)

Kim, Ki Sik; Song, Jong Nam; Kim, Seung Ok

2016-01-01

In this study, C-Arm equipment is being used as we intend to verify the exposure dose on the operator by the scattering rays during the operation of the C-Arm equipment and to provide an effective method of reducing the exposure dose. Exposure dose is less than the Over Tube method utilizes the C-arm equipment Under Tube the scheme, The result showed that the exposure dose on the operator decreased with a thicker shield, and as the operator moved away from the center line. Moreover, as the research time prolongated, the exposure dose increased, and among the three affixed location of the dosimeter, the most exposure dose was measured at gonadal, then followed by chest and thyroid. However, in consideration of the relationship between the operator and the patient, the distance cannot be increased infinitely and the research time cannot be decreased infinitely in order to reduce the exposure dose. Therefore, by changing the thickness of the radiation shield, the exposure dose on the operator was able to be reduced. If you are using a C-Arm equipment discomfort during surgery because the grounds that the procedure is neglected and close to the dose of radiation shielding made can only increase. Because a separate control room cannot be used for the C-Arm equipment due to its characteristic, the exposure dose on the operator needs to be reduced by reinforcing the shield through an appropriate thickness of radiation shield devices, such as apron, etc. during a treatment

Transfection of mouse cytotoxic T lymphocyte with an antisense granzyme A vector reduces lytic activity.

Science.gov (United States)

Talento, A; Nguyen, M; Law, S; Wu, J K; Poe, M; Blake, J T; Patel, M; Wu, T J; Manyak, C L; Silberklang, M

1992-12-15

Murine CTL have seven serine proteases, known as granzymes, in their lytic granules. Despite considerable effort, convincing evidence that these enzymes play an obligatory role in the lytic process has not been presented. To investigate the function of one of these proteases, granzyme A (GA), we utilized an antisense expression vector to lower the level of the enzyme in the cells. An expression vector containing antisense cDNA for GA and the gene for hygromycin B resistance was constructed and electroporated into the murine CTL line, AR1. Transfectants were selected based on resistance to hygromycin B, and a number of stable lines were developed. One of the antisense lines had greatly reduced levels of GA mRNA, when compared to the parental cells or to control lines transfected with the vector lacking the antisense DNA. The message levels for two other CTL granule proteins, granzyme B and perforin, were unaffected by the antisense vector. The amount of GA, as measured by enzymatic activity, was 3- to 10-fold lower in the transfectant. Most significantly, this line also consistently showed 50 to 70% lower ability to lyse nucleated target cells and to degrade their DNA. Furthermore, it exhibited 90 to 95% lower lytic activity to anti-CD3-coated SRBC. Conjugate formation with target cells, however, was normal. These data provide strong evidence that GA plays an important role in the cytolytic cycle, and that the quantity of enzyme is a limiting factor in these cytolytic cells.

Practical utilization of recombinant AAV vector reference standards: focus on vector genomes titration by free ITR qPCR

Directory of Open Access Journals (Sweden)

Susan D'Costa

2016-01-01

Full Text Available Clinical trials using recombinant adeno-associated virus (rAAV vectors have demonstrated efficacy and a good safety profile. Although the field is advancing quickly, vector analytics and harmonization of dosage units are still a limitation for commercialization. AAV reference standard materials (RSMs can help ensure product safety by controlling the consistency of assays used to characterize rAAV stocks. The most widely utilized unit of vector dosing is based on the encapsidated vector genome. Quantitative polymerase chain reaction (qPCR is now the most common method to titer vector genomes (vg; however, significant inter- and intralaboratory variations have been documented using this technique. Here, RSMs and rAAV stocks were titered on the basis of an inverted terminal repeats (ITRs sequence-specific qPCR and we found an artificial increase in vg titers using a widely utilized approach. The PCR error was introduced by using single-cut linearized plasmid as the standard curve. This bias was eliminated using plasmid standards linearized just outside the ITR region on each end to facilitate the melting of the palindromic ITR sequences during PCR. This new “Free-ITR” qPCR delivers vg titers that are consistent with titers obtained with transgene-specific qPCR and could be used to normalize in-house product-specific AAV vector standards and controls to the rAAV RSMs. The free-ITR method, including well-characterized controls, will help to calibrate doses to compare preclinical and clinical data in the field.

Practical utilization of recombinant AAV vector reference standards: focus on vector genomes titration by free ITR qPCR.

Science.gov (United States)

D'Costa, Susan; Blouin, Veronique; Broucque, Frederic; Penaud-Budloo, Magalie; François, Achille; Perez, Irene C; Le Bec, Christine; Moullier, Philippe; Snyder, Richard O; Ayuso, Eduard

2016-01-01

Clinical trials using recombinant adeno-associated virus (rAAV) vectors have demonstrated efficacy and a good safety profile. Although the field is advancing quickly, vector analytics and harmonization of dosage units are still a limitation for commercialization. AAV reference standard materials (RSMs) can help ensure product safety by controlling the consistency of assays used to characterize rAAV stocks. The most widely utilized unit of vector dosing is based on the encapsidated vector genome. Quantitative polymerase chain reaction (qPCR) is now the most common method to titer vector genomes (vg); however, significant inter- and intralaboratory variations have been documented using this technique. Here, RSMs and rAAV stocks were titered on the basis of an inverted terminal repeats (ITRs) sequence-specific qPCR and we found an artificial increase in vg titers using a widely utilized approach. The PCR error was introduced by using single-cut linearized plasmid as the standard curve. This bias was eliminated using plasmid standards linearized just outside the ITR region on each end to facilitate the melting of the palindromic ITR sequences during PCR. This new "Free-ITR" qPCR delivers vg titers that are consistent with titers obtained with transgene-specific qPCR and could be used to normalize in-house product-specific AAV vector standards and controls to the rAAV RSMs. The free-ITR method, including well-characterized controls, will help to calibrate doses to compare preclinical and clinical data in the field.

IMRT in a pregnant patient: how to reduce the fetal dose?

DEFF Research Database (Denmark)

Josipovic, Mirjana; Nyström, Håkan; Kjaer-Kristoffersen, Flemming

2008-01-01

dose distribution. The peripheral dose originating from the final IMRT plan was measured at distances reaching from the most proximal to the most distal fetal position, along the accelerator's longitudinal axis, using an anthropomorphic phantom extended with water-equivalent plastic. The measured...... was built and placed beneath the accelerator head, extending caudally from the field edge, to function as an extra collimator jaw. This shield reduced the fetal dose by a factor of 3.5. The peripheral dose components were also measured for simple rectangular fields and also here the collimator scatter...... was the greatest contributor to the peripheral dose. Therefore, the shielding used for the IMRT treatment of our patient could also be used when shielding in conventional radiotherapy. It is important for a radiation therapy department to be prepared for treatment of a pregnant patient to shield the fetus...

Intra-patient comparison of reduced-dose model-based iterative reconstruction with standard-dose adaptive statistical iterative reconstruction in the CT diagnosis and follow-up of urolithiasis

Energy Technology Data Exchange (ETDEWEB)

Tenant, Sean; Pang, Chun Lap; Dissanayake, Prageeth [Peninsula Radiology Academy, Plymouth (United Kingdom); Vardhanabhuti, Varut [Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth (United Kingdom); University of Hong Kong, Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, Pokfulam (China); Stuckey, Colin; Gutteridge, Catherine [Plymouth Hospitals NHS Trust, Plymouth (United Kingdom); Hyde, Christopher [University of Exeter Medical School, St Luke' s Campus, Exeter (United Kingdom); Roobottom, Carl [Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth (United Kingdom); Plymouth Hospitals NHS Trust, Plymouth (United Kingdom)

2017-10-15

To evaluate the accuracy of reduced-dose CT scans reconstructed using a new generation of model-based iterative reconstruction (MBIR) in the imaging of urinary tract stone disease, compared with a standard-dose CT using 30% adaptive statistical iterative reconstruction. This single-institution prospective study recruited 125 patients presenting either with acute renal colic or for follow-up of known urinary tract stones. They underwent two immediately consecutive scans, one at standard dose settings and one at the lowest dose (highest noise index) the scanner would allow. The reduced-dose scans were reconstructed using both ASIR 30% and MBIR algorithms and reviewed independently by two radiologists. Objective and subjective image quality measures as well as diagnostic data were obtained. The reduced-dose MBIR scan was 100% concordant with the reference standard for the assessment of ureteric stones. It was extremely accurate at identifying calculi of 3 mm and above. The algorithm allowed a dose reduction of 58% without any loss of scan quality. A reduced-dose CT scan using MBIR is accurate in acute imaging for renal colic symptoms and for urolithiasis follow-up and allows a significant reduction in dose. (orig.)

Use of model-based iterative reconstruction (MBIR) in reduced-dose CT for routine follow-up of patients with malignant lymphoma: dose savings, image quality and phantom study

International Nuclear Information System (INIS)

Herin, Edouard; Chiaradia, Melanie; Cavet, Madeleine; Deux, Jean-Francois; Rahmouni, Alain; Gardavaud, Francois; Beaussart, Pauline; Richard, Philippe; Haioun, Corinne; Itti, Emmanuel; Luciani, Alain

2015-01-01

To evaluate both in vivo and in phantom studies, dose reduction, and image quality of body CT reconstructed with model-based iterative reconstruction (MBIR), performed during patient follow-ups for lymphoma. This study included 40 patients (mean age 49 years) with lymphoma. All underwent reduced-dose CT during follow-up, reconstructed using MBIR or 50 % advanced statistical iterative reconstruction (ASIR). All had previously undergone a standard dose CT with filtered back projection (FBP) reconstruction. The volume CT dose index (CTDIvol), the density measures in liver, spleen, fat, air, and muscle, and the image quality (noise and signal to noise ratio, SNR) (ANOVA) observed using standard or reduced-dose CT were compared both in patients and a phantom study (Catphan 600) (Kruskal Wallis). The CTDIvol was decreased on reduced-dose body CT (4.06 mGy vs. 15.64 mGy p < 0.0001). SNR was higher in reduced-dose CT reconstructed with MBIR than in 50 % ASIR or than standard dose CT with FBP (patients, p ≤ 0.01; phantoms, p = 0.003). Low contrast detectability and spatial resolution in phantoms were not altered on MBIR-reconstructed CT (p ≥ 0.11). Reduced-dose CT with MBIR reconstruction can decrease radiation dose delivered to patients with lymphoma, while keeping an image quality similar to that obtained on standard-dose CT. (orig.)

Use of model-based iterative reconstruction (MBIR) in reduced-dose CT for routine follow-up of patients with malignant lymphoma: dose savings, image quality and phantom study

Energy Technology Data Exchange (ETDEWEB)

Herin, Edouard; Chiaradia, Melanie; Cavet, Madeleine; Deux, Jean-Francois; Rahmouni, Alain [AP-HP, Hopitaux Universitaires Henri Mondor, Imagerie Medicale, Creteil (France); Universite Paris Est Creteil, Faculte de Medecine, Creteil (France); Gardavaud, Francois; Beaussart, Pauline [AP-HP, Hopitaux Universitaires Henri Mondor, Imagerie Medicale, Creteil (France); Richard, Philippe [GE Healthcare France, Buc (France); Haioun, Corinne [Universite Paris Est Creteil, Faculte de Medecine, Creteil (France); AP-HP, Hopitaux Universitaires Henri Mondor, Hemopathies Lymphoides, Creteil (France); Itti, Emmanuel [Universite Paris Est Creteil, Faculte de Medecine, Creteil (France); AP-HP, Hopitaux Universitaires Henri Mondor, Medecine Nucleaire, Creteil (France); Luciani, Alain [AP-HP, Hopitaux Universitaires Henri Mondor, Imagerie Medicale, Creteil (France); Universite Paris Est Creteil, Faculte de Medecine, Creteil (France); INSERM Unite U 955, Creteil (France); AP-HP, Groupe Henri Mondor Albert Chenevier, Imagerie Medicale, CHU Henri Mondor, Creteil Cedex (France)

2015-08-15

To evaluate both in vivo and in phantom studies, dose reduction, and image quality of body CT reconstructed with model-based iterative reconstruction (MBIR), performed during patient follow-ups for lymphoma. This study included 40 patients (mean age 49 years) with lymphoma. All underwent reduced-dose CT during follow-up, reconstructed using MBIR or 50 % advanced statistical iterative reconstruction (ASIR). All had previously undergone a standard dose CT with filtered back projection (FBP) reconstruction. The volume CT dose index (CTDIvol), the density measures in liver, spleen, fat, air, and muscle, and the image quality (noise and signal to noise ratio, SNR) (ANOVA) observed using standard or reduced-dose CT were compared both in patients and a phantom study (Catphan 600) (Kruskal Wallis). The CTDIvol was decreased on reduced-dose body CT (4.06 mGy vs. 15.64 mGy p < 0.0001). SNR was higher in reduced-dose CT reconstructed with MBIR than in 50 % ASIR or than standard dose CT with FBP (patients, p ≤ 0.01; phantoms, p = 0.003). Low contrast detectability and spatial resolution in phantoms were not altered on MBIR-reconstructed CT (p ≥ 0.11). Reduced-dose CT with MBIR reconstruction can decrease radiation dose delivered to patients with lymphoma, while keeping an image quality similar to that obtained on standard-dose CT. (orig.)

Effects of time after infection, mosquito genotype, and infectious viral dose on the dynamics of Culex tarsalis vector competence for western equine encephalomyelitis virus.

Science.gov (United States)

Mahmood, Farida; Chiles, Robert E; Fang, Ying; Green, Emily N; Reisen, William K

2006-06-01

The vector competence of Culex tarsalis Coquillett for the BFS 1703 strain of western equine encephalomyelitis virus (WEEV) changed significantly as a function of time after infection, mosquito genotype, and infectious virus dose. After ingesting a high virus dose (5 log10 plaque-forming units [PFU]/0.1 ml), female of the susceptible high virus producer (HVP) strain rapidly amplified the virus, developed a disseminated infection, and efficiently transmitted WEEV by 4 days postinfection (dpi). The quantity of virus expectorated peaked at 4 dpi (mean 3.4 log10 PFU), and the percentage of females transmitting per os peaked at 7 dpi (80%); both measures of transmission subsequently decreased to low levels throughout the remainder of infected life. HVP females imbibing a low virus dose (3 log10 PFU/0.1 ml) were infected less frequently and took longer to amplify virus to levels recorded for the high virus dose group and did not transmit virus efficiently, thereby indicating midgut infection and escape barriers were dose and time dependent. These data emphasized the importance of elevated avian viremias in Cx. tarsalis vector competence. Females from the WEEV-resistant (WR) strain and two wild-type strains from Kern and Riverside counties were significantly less susceptible to infection at both high and low doses than was the HVP strain. Overall, females with a high virus titer more frequently had a disseminated infection, but there did not seem to be a distinct threshold demarcating this relationship. In marked contrast, all infected females transmitting virus had body titers >4.3 log10 PFU, and most had titers >4.8 log10 PFU. These data indicated that not all females with a disseminated infection transmitted virus because of the presence of one or more salivary gland barriers.

Motion Vector field improvement for picture rate conversion with reduced Halo

NARCIS (Netherlands)

Mertens, M.J.W.; Haan, de G.; Girod, B.; Bouman, C.A.; Steinbach, E.G.

2001-01-01

The quality of the interpolated images in picture rate upconversion is predominantly dependent on the accuracy of the motion vector fields. Block based MEs typically yield incorrect vectors in occlusion areas, which leads to an annoying halo in the upconverted video sequences. In the past we have

Safety of reduced dose of mycophenolate mofetil combined with tacrolimus in living-donor liver transplantation

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Hyeyoung Kim

2014-09-01

Full Text Available Background/AimsThe dose of mycophenolate mofetil (MMF has been reduced in Asia due to side effects associated with the conventional fixed dose of 2-3 g/day. We aimed to determine the pharmacokinetics of a reduced dose of MMF and to validate its feasibility in combination with tacrolimus in living-donor liver transplantation (LDLT.MethodsTwo sequential studies were performed in adult LDLT between October 2009 and 2011. First, we performed a prospective pharmacokinetic study in 15 recipients. We measured the area under the curve from 0 to 12 hours (AUC0-12 for mycophenolic acid at postoperative days 7 and 14, and we performed a protocol biopsy before discharge. Second, among 215 recipients, we reviewed 74 patients who were initially administered a reduced dose of MMF (1.0 g/day with tacrolimus (trough, 8-12 ng/mL during the first month, and 5-8 ng/mL thereafter, with a 1-year follow-up. We performed protocol biopsies at 2 weeks and 1 year post-LDLT.ResultsIn the first part of study, AUC0-12 was less than 30 mgh/L in 93.3% of cases. In the second, validating study, 41.9% of the recipients needed dose reduction or cessation due to side effects within the first year after LDLT. At 12 months post-LDLT, 17.6% of the recipients were administered a lower dose of MMF (0.5 g/day, and 16.2% needed permanent cessation due to side effects. The 1- and 12-month rejection-free survival rates were 98.6% and 97.3%, respectively.ConclusionsA reduced dose of MMF was associated with low blood levels compared to the existing recommended therapeutic range. However, reducing the dose of MMF combined with a low level of tacrolimus was feasible clinically, with an excellent short-term outcome in LDLT.

A study of a measure for reducing radiation dose in dental radiography for children

International Nuclear Information System (INIS)

Tateno, Hidemi

1982-01-01

For this investigation the author employed the stabilized TLD and measured the effect of doses on several organs (of children) using water and Mix-D phantom. Based upon this data, the author developed an exposure cone (of children) which was thought to be the best concrete method for reduction of absorbed doses for children who are most frequentry X-rayed and therefore most likely to reduced absorbed doses in a considerable amount. The major findings have been obtained concerning this cone compared with the standard cone as follows. 1. The full mouth 6-film examination showed the largest of the absorbed doses to be on skin, eyes and the thyroid gland. 2. For example, the dose on thyroid gland with a full mouth 6-film examination was 0.734R. 3. The dose on the gonad was less than 0.001R with every technique. 4. Using the developed exposure cone for children we have succeeded in reducing the amount of doses on these organs. In addition the image quality improved due to the reduction of scattered X-rays. 5. Using the developed exposure cone (for children) the risk of thyroid cancer can be reduced a level of 10 -6 to a level of 10 -7 as compared with the standard exposure cone. 6. Supposing that it is over the crystalline lens limits of dose-equivalent in a year at several times with full mouth 6-film examinations can be estimated which with standard cone was about three times, developed cone was about eighty-eight times in a year. (J.P.N.)

An antivector vaccine protects against a lethal vector-borne pathogen.

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Milan Labuda

2006-04-01

Full Text Available Vaccines that target blood-feeding disease vectors, such as mosquitoes and ticks, have the potential to protect against the many diseases caused by vector-borne pathogens. We tested the ability of an anti-tick vaccine derived from a tick cement protein (64TRP of Rhipicephalus appendiculatus to protect mice against tick-borne encephalitis virus (TBEV transmitted by infected Ixodes ricinus ticks. The vaccine has a "dual action" in immunized animals: when infested with ticks, the inflammatory and immune responses first disrupt the skin feeding site, resulting in impaired blood feeding, and then specific anti-64TRP antibodies cross-react with midgut antigenic epitopes, causing rupture of the tick midgut and death of engorged ticks. Three parameters were measured: "transmission," number of uninfected nymphal ticks that became infected when cofeeding with an infected adult female tick; "support," number of mice supporting virus transmission from the infected tick to cofeeding uninfected nymphs; and "survival," number of mice that survived infection by tick bite and subsequent challenge by intraperitoneal inoculation of a lethal dose of TBEV. We show that one dose of the 64TRP vaccine protects mice against lethal challenge by infected ticks; control animals developed a fatal viral encephalitis. The protective effect of the 64TRP vaccine was comparable to that of a single dose of a commercial TBEV vaccine, while the transmission-blocking effect of 64TRP was better than that of the antiviral vaccine in reducing the number of animals supporting virus transmission. By contrast, the commercial antitick vaccine (TickGARD that targets only the tick's midgut showed transmission-blocking activity but was not protective. The 64TRP vaccine demonstrates the potential to control vector-borne disease by interfering with pathogen transmission, apparently by mediating a local cutaneous inflammatory immune response at the tick-feeding site.

Estimating normal mixture parameters from the distribution of a reduced feature vector

Science.gov (United States)

Guseman, L. F.; Peters, B. C., Jr.; Swasdee, M.

1976-01-01

A FORTRAN computer program was written and tested. The measurements consisted of 1000 randomly chosen vectors representing 1, 2, 3, 7, and 10 subclasses in equal portions. In the first experiment, the vectors are computed from the input means and covariances. In the second experiment, the vectors are 16 channel measurements. The starting covariances were constructed as if there were no correlation between separate passes. The biases obtained from each run are listed.

Realistic simulation of reduced-dose CT with noise modeling and sinogram synthesis using DICOM CT images

International Nuclear Information System (INIS)

Won Kim, Chang; Kim, Jong Hyo

2014-01-01

Purpose: Reducing the patient dose while maintaining the diagnostic image quality during CT exams is the subject of a growing number of studies, in which simulations of reduced-dose CT with patient data have been used as an effective technique when exploring the potential of various dose reduction techniques. Difficulties in accessing raw sinogram data, however, have restricted the use of this technique to a limited number of institutions. Here, we present a novel reduced-dose CT simulation technique which provides realistic low-dose images without the requirement of raw sinogram data. Methods: Two key characteristics of CT systems, the noise equivalent quanta (NEQ) and the algorithmic modulation transfer function (MTF), were measured for various combinations of object attenuation and tube currents by analyzing the noise power spectrum (NPS) of CT images obtained with a set of phantoms. Those measurements were used to develop a comprehensive CT noise model covering the reduced x-ray photon flux, object attenuation, system noise, and bow-tie filter, which was then employed to generate a simulated noise sinogram for the reduced-dose condition with the use of a synthetic sinogram generated from a reference CT image. The simulated noise sinogram was filtered with the algorithmic MTF and back-projected to create a noise CT image, which was then added to the reference CT image, finally providing a simulated reduced-dose CT image. The simulation performance was evaluated in terms of the degree of NPS similarity, the noise magnitude, the bow-tie filter effect, and the streak noise pattern at photon starvation sites with the set of phantom images. Results: The simulation results showed good agreement with actual low-dose CT images in terms of their visual appearance and in a quantitative evaluation test. The magnitude and shape of the NPS curves of the simulated low-dose images agreed well with those of real low-dose images, showing discrepancies of less than +/−3.2% in

Eliminating HIV-1 Packaging Sequences from Lentiviral Vector Proviruses Enhances Safety and Expedites Gene Transfer for Gene Therapy.

Science.gov (United States)

Vink, Conrad A; Counsell, John R; Perocheau, Dany P; Karda, Rajvinder; Buckley, Suzanne M K; Brugman, Martijn H; Galla, Melanie; Schambach, Axel; McKay, Tristan R; Waddington, Simon N; Howe, Steven J

2017-08-02

Lentiviral vector genomic RNA requires sequences that partially overlap wild-type HIV-1 gag and env genes for packaging into vector particles. These HIV-1 packaging sequences constitute 19.6% of the wild-type HIV-1 genome and contain functional cis elements that potentially compromise clinical safety. Here, we describe the development of a novel lentiviral vector (LTR1) with a unique genomic structure designed to prevent transfer of HIV-1 packaging sequences to patient cells, thus reducing the total HIV-1 content to just 4.8% of the wild-type genome. This has been achieved by reconfiguring the vector to mediate reverse-transcription with a single strand transfer, instead of the usual two, and in which HIV-1 packaging sequences are not copied. We show that LTR1 vectors offer improved safety in their resistance to remobilization in HIV-1 particles and reduced frequency of splicing into human genes. Following intravenous luciferase vector administration to neonatal mice, LTR1 sustained a higher level of liver transgene expression than an equivalent dose of a standard lentivirus. LTR1 vectors produce reverse-transcription products earlier and start to express transgenes significantly quicker than standard lentiviruses after transduction. Finally, we show that LTR1 is an effective lentiviral gene therapy vector as demonstrated by correction of a mouse hemophilia B model. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Treatment for meibomian gland dysfunction and dry eye symptoms with a single-dose vectored thermal pulsation: a review.

Science.gov (United States)

Blackie, Caroline A; Carlson, Alan N; Korb, Donald R

2015-07-01

Meibomian gland dysfunction (MGD) is understood to be a highly prevalent, chronic progressive disease and the leading cause of dry eye. All available published peer-reviewed results of the novel vectored thermal pulsation therapy for patients with MGD are investigated. The PubMed and meeting abstract search revealed a total of 31 peer-reviewed reports on vectored thermal pulsation therapy at the time of the search (eight manuscripts and 23 meeting abstracts). All manuscripts evidence a significant increase in meibomian gland function (∼3×) and symptom improvement post a single 12-min treatment. Additional reported objective measures such as osmolarity, tear break-up time, or lipid layer thickness also increased as a result of the therapy; however, not all findings were statistically significant. The randomized controlled studies evidence sustained gland function and symptom relief lasting out to 12 months. The uncontrolled case series evidence significantly longer duration of effect. A single 12 minute vectored thermal pulsation treatment allows for reducing dry eye symptoms, improving meibomian gland function and other correlates of the ocular surface health.

EVALUATION OF SUBLETHAL EFFECTS OF Ipomoea cairica LINN. EXTRACT ON LIFE HISTORY TRAITS OF DENGUE VECTORS

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Wan Fatma ZUHARAH

2016-01-01

Full Text Available Plant derived insecticides have considerable potential for mosquito control because these products are safer than conventional insecticides. This study aimed to investigate sublethal activities of Ipomoea carica or railway creeper crude acethonilic extract against life history trait of dengue vectors, Aedes albopictus and Aedes aegypti. The late third instar larvae of Ae. albopictus and Ae. aegypti were exposed to a sublethal dose at LC50 and larvae that survived were further cultured. Overall, Ipomea cairica crude extracts affected the whole life history of both Aedes species. The study demonstrated significantly lower egg production (fecundity and eggs hatchability (fertility in Ae. albopictus. The sublethal dose of crude extracts reduced significantly the width of larval head capsule and the wing length of both sexes in both Aedes species. The significance of sublethal effects of I. cairica against Aedes mosquitoes was an additional hallmark to demonstrate further activity of this plant despite its direct toxicity to the larvae. The reduced reproductive capacity as well as morphological and physiological anomalies are some of the effects that make I. cairica a potential candidate to be used as a new plant-based insecticide to control dengue vectors.

A method to reduce patient's eye lens dose in neuro-interventional radiology procedures

International Nuclear Information System (INIS)

Safari, M.J.; Wong, J.H.D.; Kadir, K.A.A.; Sani, F.M.; Ng, K.H.

2016-01-01

Complex and prolonged neuro-interventional radiology procedures using the biplane angiography system increase the patient's risk of radiation-induced cataract. Physical collimation is the most effective way of reducing the radiation dose to the patient's eye lens, but in instances where collimation is not possible, an attenuator may be useful in protecting the eyes. In this study, an eye lens protector was designed and fabricated to reduce the radiation dose to the patients’ eye lens during neuro-interventional procedures. The eye protector was characterised before being tested on its effectiveness in a simulated aneurysm procedure on an anthropomorphic phantom. Effects on the automatic dose rate control (ADRC) and image quality are also evaluated. The eye protector reduced the radiation dose by up to 62.1% at the eye lens. The eye protector is faintly visible in the fluoroscopy images and increased the tube current by a maximum of 3.7%. It is completely invisible in the acquisition mode and does not interfere with the clinical procedure. The eye protector placed within the radiation field of view was able to reduce the radiation dose to the eye lens by direct radiation beam of the lateral x-ray tube with minimal effect on the ADRC system. - Highlights: • The eye protector can considerably reduce the patient's eye lens dose during neuro-interventional procedures. • This protector does not significantly perturb the fluoroscopy image and was completely invisible on the acquisition image due to image subtraction. • The eye protector does not significantly change the exposure parameters (kV and mAs).

Environmental and biological factors influencing Culex pipiens quinquefasciatus (Diptera: Culicidae) vector competence for West Nile Virus.

Science.gov (United States)

Richards, Stephanie L; Lord, Cynthia C; Pesko, Kendra N; Tabachnick, Walter J

2010-07-01

Interactions between environmental and biological factors affect the vector competence of Culex pipiens quinquefasciatus for West Nile virus. Three age cohorts from two Cx. p. quinquefasciatus colonies were fed blood containing a low- or high-virus dose, and each group was held at two different extrinsic incubation temperatures (EIT) for 13 days. The colonies differed in the way that they responded to the effects of the environment on vector competence. The effects of mosquito age on aspects of vector competence were dependent on the EIT and dose, and they changed depending on the colony. Complex interactions must be considered in laboratory studies of vector competence, because the extent of the genetic and environmental variation controlling vector competence in nature is largely unknown. Differences in the environmental (EIT and dose) and biological (mosquito age and colony) effects from previous studies of Cx. p. quinquefasciatus vector competence for St. Louis encephalitis virus are discussed.

Chromobacterium Csp_P reduces malaria and dengue infection in vector mosquitoes and has entomopathogenic and in vitro anti-pathogen activities.

Science.gov (United States)

Ramirez, Jose Luis; Short, Sarah M; Bahia, Ana C; Saraiva, Raul G; Dong, Yuemei; Kang, Seokyoung; Tripathi, Abhai; Mlambo, Godfree; Dimopoulos, George

2014-10-01

Plasmodium and dengue virus, the causative agents of the two most devastating vector-borne diseases, malaria and dengue, are transmitted by the two most important mosquito vectors, Anopheles gambiae and Aedes aegypti, respectively. Insect-bacteria associations have been shown to influence vector competence for human pathogens through multi-faceted actions that include the elicitation of the insect immune system, pathogen sequestration by microbes, and bacteria-produced anti-pathogenic factors. These influences make the mosquito microbiota highly interesting from a disease control perspective. Here we present a bacterium of the genus Chromobacterium (Csp_P), which was isolated from the midgut of field-caught Aedes aegypti. Csp_P can effectively colonize the mosquito midgut when introduced through an artificial nectar meal, and it also inhibits the growth of other members of the midgut microbiota. Csp_P colonization of the midgut tissue activates mosquito immune responses, and Csp_P exposure dramatically reduces the survival of both the larval and adult stages. Ingestion of Csp_P by the mosquito significantly reduces its susceptibility to Plasmodium falciparum and dengue virus infection, thereby compromising the mosquito's vector competence. This bacterium also exerts in vitro anti-Plasmodium and anti-dengue activities, which appear to be mediated through Csp_P -produced stable bioactive factors with transmission-blocking and therapeutic potential. The anti-pathogen and entomopathogenic properties of Csp_P render it a potential candidate for the development of malaria and dengue control strategies.

Quality control of diagnostic radiology to reduce absorbed dose of patients in Iran

International Nuclear Information System (INIS)

Aghahadi, Bahman.

1996-01-01

In order to reduce absorbed dose, to increase the image quality and to reduce the numbers of rejected films various quality control parameters were applied to X ray machines. These parameter are Kilo Volt peak, Milli Ampere, Exposure Time Focal Film Distance, Inherent Filters, Additional Filters Half Value Layer, Processor Condition, Cassettes. To evaluate and to apply these parameters in diagnostic radiological centers, ten hospitals were selected and a total number of 12 X ray machines were kept under quality control program. Considering different kinds of diagnostic radiology examination and to compare the dose before and after implementation of a quality control program, two kinds of examinations include in chest and abdomen examinations were considered. For each X ray machine, ten patients and for all selected centers, 120 patients were selected for chest examination and 120 patients for abdomen examinations; before and after implementation of quality control program, a total of 480 patients were selected randomly to be controlled. Base on different examinations carried out, it was concluded that both exposure conditions and general situations in radiological centers were not acceptable. The dosimetry results show that the average ski dose for chest and abdomen examinations were 0.28 m Gy and 4.23 Gy respectively. Before implementation of quality control step to reduce the surface skin dose, quality control parameters were applied and the exposure conditions were imposed. On average the absorbed doses for chest and abdomen examination were decreased to 79% and 61% respectively after the implementation of the program. From dose reduction point of view, the results of a part of this project which made by co-operation of International Atomic Energy Agency showed that Iran acquired the first grade for chest examination and second grade for abdomen examination. Base on the results obtained, the number of patients under chest and abdomen examination were 4041588 and

Ovarian and endocrine responses in tropical sheep treated with reduced doses of cloprostenol.

Science.gov (United States)

Contreras-Solis, Ignacio; Vasquez, B; Diaz, T; Letelier, C; Lopez-Sebastian, A; Gonzalez-Bulnes, A

2009-09-01

The present study aimed to assess the efficacy of reduced doses of cloprostenol for synchronizing estrus and ovulation in hair sheep. With the aim to evaluate the luteolytic activity of reduced cloprostenol doses, a first experiment was performed using a relatively large (group H: 126 microg; n=8), medium (group M: 68.25 microg; n=6) and small (group L: 38.5 microg; n=6) cloprostenol dose. Luteolysis was assessed at Days 3 and 6 after injection (Day 0) by progesterone concentrations (P(4)) and transrectal ultrasonography (US). In Experiment 2, sheep were randomly assigned to the same three doses to evaluate a protocol for estrous synchronization using two injections administered 9 days apart. A third trial was performed with ewes treated (9 days apart) with the large dose (H=126 microg; n=12) and with a small dose adjusted for facilitating volume management (LA=43.75 microg; n=12). Presence of estrous cycling was determined in all the ewes by US and P(4) assay, at Days -9, -6, -2, 0 (Day of second cloprostenol injection), 8 and 11. Bleeding and US were done every 4h from 16 h of the beginning of the estrus during the third trial to assess the preovulatory LH surge and timing of ovulation. Additionally, blood samples were drawn at Days 0, 1, 2 and 3 to assess estradiol (Experiments 2 and 3) and P(4) (Experiment 2) concentrations during the ovarian follicular phase. In all experiments, percentage of animals showing luteolysis, preovulatory follicular dynamics and function and percentage of ewes showing behavioral estrus in response to treatment was similar among groups. Timing of estrus for group H was earlier than group L (28.6+/-1.8h compared with 37.1+/-2.4h; Psheep, with the additional advantage of reducing treatment costs.

Integrating Transgenic Vector Manipulation with Clinical Interventions to Manage Vector-Borne Diseases.

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Kenichi W Okamoto

2016-03-01

Full Text Available Many vector-borne diseases lack effective vaccines and medications, and the limitations of traditional vector control have inspired novel approaches based on using genetic engineering to manipulate vector populations and thereby reduce transmission. Yet both the short- and long-term epidemiological effects of these transgenic strategies are highly uncertain. If neither vaccines, medications, nor transgenic strategies can by themselves suffice for managing vector-borne diseases, integrating these approaches becomes key. Here we develop a framework to evaluate how clinical interventions (i.e., vaccination and medication can be integrated with transgenic vector manipulation strategies to prevent disease invasion and reduce disease incidence. We show that the ability of clinical interventions to accelerate disease suppression can depend on the nature of the transgenic manipulation deployed (e.g., whether vector population reduction or replacement is attempted. We find that making a specific, individual strategy highly effective may not be necessary for attaining public-health objectives, provided suitable combinations can be adopted. However, we show how combining only partially effective antimicrobial drugs or vaccination with transgenic vector manipulations that merely temporarily lower vector competence can amplify disease resurgence following transient suppression. Thus, transgenic vector manipulation that cannot be sustained can have adverse consequences-consequences which ineffective clinical interventions can at best only mitigate, and at worst temporarily exacerbate. This result, which arises from differences between the time scale on which the interventions affect disease dynamics and the time scale of host population dynamics, highlights the importance of accounting for the potential delay in the effects of deploying public health strategies on long-term disease incidence. We find that for systems at the disease-endemic equilibrium, even

Performances of low-dose dual-energy CT in reducing artifacts from implanted metallic orthopedic devices

Energy Technology Data Exchange (ETDEWEB)

Filograna, Laura [Catholic University of Rome, School of Medicine, University Hospital ' ' A. Gemelli' ' , Department of Radiological Sciences, Institute of Radiology, Rome (Italy); University of Zurich, Department of Forensic Medicine and Imaging, Institute of Forensic Medicine, Zurich (Switzerland); Magarelli, Nicola; Leone, Antonio; Bonomo, Lorenzo [Catholic University of Rome, School of Medicine, University Hospital ' ' A. Gemelli' ' , Department of Radiological Sciences, Institute of Radiology, Rome (Italy); De Waure, Chiara; Calabro, Giovanna Elisa [Catholic University of Rome, School of Medicine, University Hospital ' ' A. Gemelli' ' , Research Centre for Health Technology Assessment, Department of Public Health, Section of Hygiene, Rome (Italy); Finkenstaedt, Tim [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Thali, Michael John [University of Zurich, Department of Forensic Medicine and Imaging, Institute of Forensic Medicine, Zurich (Switzerland)

2016-07-15

The objective was to evaluate the performances of dose-reduced dual-energy computed tomography (DECT) in decreasing metallic artifacts from orthopedic devices compared with dose-neutral DECT, dose-neutral single-energy computed tomography (SECT), and dose-reduced SECT. Thirty implants in 20 consecutive cadavers underwent both SECT and DECT at three fixed CT dose indexes (CTDI): 20.0, 10.0, and 5.0 mGy. Extrapolated monoenergetic DECT images at 64, 69, 88, 105, 120, and 130 keV, and individually adjusted monoenergy for optimized image quality (OPTkeV) were generated. In each group, the image quality of the seven monoenergetic images and of the SECT image was assessed qualitatively and quantitatively by visually rating and by measuring the maximum streak artifact respectively. The comparison between SECT and OPTkeV evaluated overall within all groups showed a significant difference (p <0.001), with OPTkeV images providing better images. Comparing OPTkeV with the other DECT images, a significant difference was shown (p <0.001), with OPTkeV and 130-keV images providing the qualitatively best results. The OPTkeV images of 5.0-mGy acquisitions provided percentages of images with scores 1 and 2 of 36 % and 30 % respectively, compared with 0 % and 33.3 % of the corresponding SECT images of 10- and 20-mGy acquisitions. Moreover, DECT reconstructions at the OPTkeV of the low-dose group showed higher CT numbers than the SECT images of dose groups 1 and 2. This study demonstrates that low-dose DECT permits a reduction of artifacts due to metallic implants to be obtained in a similar manner to neutral-dose DECT and better than reduced or neutral-dose SECT. (orig.)

Reduced Albumin Dosing During Large-Volume Paracentesis Is Not Associated with Adverse Clinical Outcomes.

Science.gov (United States)

Johnson, Kara B; Mueller, Jessica L; Simon, Tracey G; Zheng, Hui; King, Lindsay Y; Makar, Robert S; Gervais, Debra A; Chung, Raymond T

2015-07-01

LVP is used to manage diuretic-resistant ascites in cirrhotic patients. Albumin administration prevents complications including acute kidney injury and paracentesis-induced circulatory dysfunction, but the optimal dose is unclear. We sought to assess adherence to guidelines enacted in July 2011 at our center for reducing the albumin dose administered at large-volume paracentesis (LVP) and evaluate the cost and rate of complications of LVPs before and after guideline enactment. All LVPs performed on cirrhotic patients in our center's Department of Radiology between July 2009 and January 2014 were studied. Outcomes included adherence to guidelines, LVP complications, and administered albumin cost. Groups were compared using Student's t tests for continuous data and Chi-square or Fisher's exact tests for categorical data. A repeated measurements model accounted for patients with multiple LVPs. Of the 935 LVPs, 288 occurred before guideline implementation (group 1) and 647 occurred after (group 2). The mean dose of albumin administered was 13.7 g/L of ascites removed in group 1 versus 10.3 g/L in group 2 (p albumin administration and associated cost savings was still observed. There was no increase in LVP-related complications after guideline implementation or in the adherent group, suggesting that albumin dose can be safely reduced. Future efforts should be directed at enhancing guideline adherence and potentially further reducing albumin dosing.

Study on the method or reducing the operator's exposure dose from a C-Arm system

Energy Technology Data Exchange (ETDEWEB)

Kim, Ki Sik; Song, Jong Nam [Dept. of Radiological Science, Dongshin University, Naju (Korea, Republic of); Kim, Seung Ok [Dept. of Radiology, Catholic Kwangdong Universty International ST.Mary' s Hospital, Incheon (Korea, Republic of)

2016-12-15

In this study, C-Arm equipment is being used as we intend to verify the exposure dose on the operator by the scattering rays during the operation of the C-Arm equipment and to provide an effective method of reducing the exposure dose. Exposure dose is less than the Over Tube method utilizes the C-arm equipment Under Tube the scheme, The result showed that the exposure dose on the operator decreased with a thicker shield, and as the operator moved away from the center line. Moreover, as the research time prolongated, the exposure dose increased, and among the three affixed location of the dosimeter, the most exposure dose was measured at gonadal, then followed by chest and thyroid. However, in consideration of the relationship between the operator and the patient, the distance cannot be increased infinitely and the research time cannot be decreased infinitely in order to reduce the exposure dose. Therefore, by changing the thickness of the radiation shield, the exposure dose on the operator was able to be reduced. If you are using a C-Arm equipment discomfort during surgery because the grounds that the procedure is neglected and close to the dose of radiation shielding made can only increase. Because a separate control room cannot be used for the C-Arm equipment due to its characteristic, the exposure dose on the operator needs to be reduced by reinforcing the shield through an appropriate thickness of radiation shield devices, such as apron, etc. during a treatment.

Evaluation of bismuth shielding effectiveness in reducing breast absorbed dose during thoracic CT scan

Energy Technology Data Exchange (ETDEWEB)

Alonso, T. C.; Mourao, A. P.; Santana, P. C.; Silva, T. A. [Federal University of Minas Gerais, Program of Nuclear Science and Techniques, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil)

2015-10-15

Computed Tomography (CT) is an essential method for tracking neoplasia and efficiently diagnosing a wide variety of thoracic diseases. CT is generally considered the most accurate choice for lung examination. Due to the growing use of CT, breast and other superficial and radiosensitive organs are unnecessarily irradiated during radiological procedures, thus requiring the development of strategies appropriate to optimize and, if possible, to reduce the radiation dose. The use of bismuth shielding to reduce radiation dose absorbed by breast during thoracic CT examinations has been the subject of many studies recently published by Brazilian and foreign authors of various fields. The purpose of this paper is both to accurately determine the glandular dose when breast is exposed to radiation and to assess the reduction in absorbed dose during thoracic CT examinations, using a set of Thermoluminescent Dosimeters, an anthropomorphic phantom and bismuth shielding. (Author)

Evaluation of bismuth shielding effectiveness in reducing breast absorbed dose during thoracic CT scan

International Nuclear Information System (INIS)

Alonso, T. C.; Mourao, A. P.; Santana, P. C.; Silva, T. A.

2015-10-01

Computed Tomography (CT) is an essential method for tracking neoplasia and efficiently diagnosing a wide variety of thoracic diseases. CT is generally considered the most accurate choice for lung examination. Due to the growing use of CT, breast and other superficial and radiosensitive organs are unnecessarily irradiated during radiological procedures, thus requiring the development of strategies appropriate to optimize and, if possible, to reduce the radiation dose. The use of bismuth shielding to reduce radiation dose absorbed by breast during thoracic CT examinations has been the subject of many studies recently published by Brazilian and foreign authors of various fields. The purpose of this paper is both to accurately determine the glandular dose when breast is exposed to radiation and to assess the reduction in absorbed dose during thoracic CT examinations, using a set of Thermoluminescent Dosimeters, an anthropomorphic phantom and bismuth shielding. (Author)

Reduced fungicide doses in cereals: Which parameters to consider?

DEFF Research Database (Denmark)

Jørgensen, Lise Nistrup

2015-01-01

dose. In spring barley the economically optimum input can vary from 0-2 treatments with a total fungicide use equivalent to 0.25 to 0.5 times the recommended dose. Applying reducing rates should never result in significant inferior control and economical yield losses. A recent review concluded......, the pathogen, disease pressure and timing of treatments. Certain diseases are known to require higher input (40- 75% rates) for achieving satisfactory control – this is the case for Septoria leaf blight, Rhynchosporium net blotch and Fusarium head blight, whereas most rust diseases generally have been found...... on well-established disease attack. Rates also have to be adjusted according to canopy structures. Early timing on a small canopy requires less fungicide than a full canopy around heading. The knowledge gathered concerning fungicide rates has led to great focus on the importance of optimizing timing...

Immunogenicity in African Green Monkeys of M Protein Mutant Vesicular Stomatitis Virus Vectors and Contribution of Vector-Encoded Flagellin

Directory of Open Access Journals (Sweden)

Marlena M. Westcott

2018-03-01

Full Text Available Recombinant vesicular stomatitis virus (VSV is a promising platform for vaccine development. M51R VSV, an attenuated, M protein mutant strain, is an effective inducer of Type I interferon and dendritic cell (DC maturation, which are desirable properties to exploit for vaccine design. We have previously evaluated M51R VSV (M51R and M51R VSV that produces flagellin (M51R-F as vaccine vectors using murine models, and found that flagellin enhanced DC activation and VSV-specific antibody production after low-dose vaccination. In this report, the immunogenicity of M51R vectors and the adjuvant effect of virus-produced flagellin were evaluated in nonhuman primates following high-dose (108 pfu and low-dose (105 pfu vaccination. A single intramuscular vaccination of African green monkeys with M51R or M51R-F induced VSV-specific, dose-dependent humoral immune responses. Flagellin induced a significant increase in antibody production (IgM, IgG and neutralizing antibody at the low vaccination dose. A VSV-specific cellular response was detected at 6 weeks post-vaccination, but was neither dose-dependent nor enhanced by flagellin; similar numbers of VSV-specific, IFNγ-producing cells were detected in lymph node and spleen of all animals. These results indicate that virus-directed, intracellular flagellin production may improve VSV-based vaccines encoding heterologous antigens by lowering the dose required to achieve humoral immunity.

Doses of Coronary Study in 64 Channel Multi-Detector Computed Tomography : Reduced Radiation Dose According to Varity of Examnination Protocols

International Nuclear Information System (INIS)

Kim, Moon Chan

2009-01-01

that of conventional coronary CTA. And heart dose was 33.8 mGy, this represents 67.4% reduction. In the sequential scan technique under prospective ECG gating with low kVp the mean effective dose was 3.0 mSv, this represents an 83.2% reduction compared with that of conventional coronary CTA. And heart dose was 17.7 mGy, this represents an 82.9% reduction. In coronary CTA at retrospectively ECG gated helical scan, cardiac dose modulation technique using low kVp reduced dose to 50% above compared with the conventional helical scan. And the prospectively ECG gated sequential scan offers substantially reduced dose compared with the traditional retrospectively ECG gated helical scan.

Phase 2 clinical trial of a recombinant adeno-associated viral vector expressing α1-antitrypsin: interim results.

LENUS (Irish Health Repository)

Flotte, Terence R

2011-10-01

Recombinant adeno-associated virus (rAAV) vectors offer promise for the gene therapy of α(1)-antitrypsin (AAT) deficiency. In our prior trial, an rAAV vector expressing human AAT (rAAV1-CB-hAAT) provided sustained, vector-derived AAT expression for >1 year. In the current phase 2 clinical trial, this same vector, produced by a herpes simplex virus complementation method, was administered to nine AAT-deficient individuals by intramuscular injection at doses of 6.0×10(11), 1.9×10(12), and 6.0×10(12) vector genomes\\/kg (n=3 subjects\\/dose). Vector-derived expression of normal (M-type) AAT in serum was dose dependent, peaked on day 30, and persisted for at least 90 days. Vector administration was well tolerated, with only mild injection site reactions and no serious adverse events. Serum creatine kinase was transiently elevated on day 30 in five of six subjects in the two higher dose groups and normalized by day 45. As expected, all subjects developed anti-AAV antibodies and interferon-γ enzyme-linked immunospot responses to AAV peptides, and no subjects developed antibodies to AAT. One subject in the mid-dose group developed T cell responses to a single AAT peptide unassociated with any clinical effects. Muscle biopsies obtained on day 90 showed strong immunostaining for AAT and moderate to marked inflammatory cell infiltrates composed primarily of CD3-reactive T lymphocytes that were primarily of the CD8(+) subtype. These results support the feasibility and safety of AAV gene therapy for AAT deficiency, and indicate that serum levels of vector-derived normal human AAT >20 μg\\/ml can be achieved. However, further improvements in the design or delivery of rAAV-AAT vectors will be required to achieve therapeutic target serum AAT concentrations.

An introduction to vectors, vector operators and vector analysis

CERN Document Server

Joag, Pramod S

2016-01-01

Ideal for undergraduate and graduate students of science and engineering, this book covers fundamental concepts of vectors and their applications in a single volume. The first unit deals with basic formulation, both conceptual and theoretical. It discusses applications of algebraic operations, Levi-Civita notation, and curvilinear coordinate systems like spherical polar and parabolic systems and structures, and analytical geometry of curves and surfaces. The second unit delves into the algebra of operators and their types and also explains the equivalence between the algebra of vector operators and the algebra of matrices. Formulation of eigen vectors and eigen values of a linear vector operator are elaborated using vector algebra. The third unit deals with vector analysis, discussing vector valued functions of a scalar variable and functions of vector argument (both scalar valued and vector valued), thus covering both the scalar vector fields and vector integration.

Heterologous Two-Dose Vaccination with Simian Adenovirus and Poxvirus Vectors Elicits Long-Lasting Cellular Immunity to Influenza Virus A in Healthy Adults

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L. Coughlan

2018-03-01

Full Text Available Background: T-cell responses against highly conserved influenza antigens have been previously associated with protection. However, these immune responses are poorly maintained following recovery from influenza infection and are not boosted by inactivated influenza vaccines. We have previously demonstrated the safety and immunogenicity of two viral vectored vaccines, modified vaccinia virus Ankara (MVA and the chimpanzee adenovirus ChAdOx1 expressing conserved influenza virus antigens, nucleoprotein (NP and matrix protein-1 (M1. We now report on the safety and long-term immunogenicity of multiple combination regimes of these vaccines in young and older adults. Methods: We conducted a Phase I open-label, randomized, multi-center study in 49 subjects aged 18–46 years and 24 subjects aged 50 years or over. Following vaccination, adverse events were recorded and the kinetics of the T cell response determined at multiple time points for up to 18 months. Findings: Both vaccines were well tolerated. A two dose heterologous vaccination regimen significantly increased the magnitude of pre-existing T-cell responses to NP and M1 after both doses in young and older adults. The fold-increase and peak immune responses after a single MVA-NP + M1 vaccination was significantly higher compared to ChAdOx1 NP + M1. In a mixed regression model, T-cell responses over 18 months were significantly higher following the two dose vaccination regimen of MVA/ChAdOx1 NP + M1. Interpretation: A two dose heterologous vaccination regimen of MVA/ChAdOx1 NP + M1 was safe and immunogenic in young and older adults, offering a promising vaccination strategy for inducing long-term broadly cross-reactive protection against influenza A. Funding Source: Medical Research Council UK, NIHR BMRC Oxford. Keywords: Influenza, T-cell responses, Influenza vaccines, Viral vectors, Adults, Older adults

IL-10 mediated by herpes simplex virus vector reduces neuropathic pain induced by HIV gp120 combined with ddC in rats.

Science.gov (United States)

Zheng, Wenwen; Huang, Wan; Liu, Shue; Levitt, Roy C; Candiotti, Keith A; Lubarsky, David A; Hao, Shuanglin

2014-07-30

HIV-associated sensory neuropathy affects over 50% of HIV patients and is a common peripheral nerve complication of HIV infection and highly active antiretroviral therapy (HAART). Evidence shows that painful HIV sensory neuropathy is influenced by neuroinflammatory events that include the proinflammatory molecules, MAP Kinase, tumor necrosis factor-α (TNFα), stromal cell-derived factor 1-α (SDF1α), and C-X-C chemokine receptor type 4 (CXCR4). However, the exact mechanisms of painful HIV sensory neuropathy are not known, which hinders our ability to develop effective treatments. In this study, we investigated whether inhibition of proinflammatory factors reduces the HIV-associated neuropathic pain state. Neuropathic pain was induced by peripheral HIV coat protein gp120 combined with 2',3'-dideoxycytidine (ddC, one of the nucleoside reverse transcriptase inhibitors (NRTIs)). Mechanical threshold was tested using von Frey filament fibers. Non-replicating herpes simplex virus (HSV) vectors expressing interleukin 10 (IL10) were inoculated into the hindpaws of rats. The expression of TNFα, SDF1α, and CXCR4 in the lumbar spinal cord and L4/5 dorsal root ganglia (DRG) was examined using western blots. IL-10 expression mediated by the HSV vectors resulted in a significant elevation of mechanical threshold. The anti-allodynic effect of IL-10 expression mediated by the HSV vectors lasted more than 3 weeks. The area under the effect-time curves (AUC) in mechanical threshold in rats inoculated with the HSV vectors expressing IL-10, was increased compared with the control vectors, indicating antinociceptive effect of the IL-10 vectors. The HSV vectors expressing IL-10 also concomitantly reversed the upregulation of p-p38, TNFα, SDF1α, and CXCR4 induced by gp120 in the lumbar spinal dorsal horn and/or the DRG at 2 and/or 4 weeks. The blocking of the signaling of these proinflammatory molecules is able to reduce HIV-related neuropathic pain, which provide a novel

Integration profile and safety of an adenovirus hybrid-vector utilizing hyperactive sleeping beauty transposase for somatic integration.

Directory of Open Access Journals (Sweden)

Wenli Zhang

Full Text Available We recently developed adenovirus/transposase hybrid-vectors utilizing the previously described hyperactive Sleeping Beauty (SB transposase HSB5 for somatic integration and we could show stabilized transgene expression in mice and a canine model for hemophilia B. However, the safety profile of these hybrid-vectors with respect to vector dose and genotoxicity remains to be investigated. Herein, we evaluated this hybrid-vector system in C57Bl/6 mice with escalating vector dose settings. We found that in all mice which received the hyperactive SB transposase, transgene expression levels were stabilized in a dose-dependent manner and that the highest vector dose was accompanied by fatalities in mice. To analyze potential genotoxic side-effects due to somatic integration into host chromosomes, we performed a genome-wide integration site analysis using linker-mediated PCR (LM-PCR and linear amplification-mediated PCR (LAM-PCR. Analysis of genomic DNA samples obtained from HSB5 treated female and male mice revealed a total of 1327 unique transposition events. Overall the chromosomal distribution pattern was close-to-random and we observed a random integration profile with respect to integration into gene and non-gene areas. Notably, when using the LM-PCR protocol, 27 extra-chromosomal integration events were identified, most likely caused by transposon excision and subsequent transposition into the delivered adenoviral vector genome. In total, this study provides a careful evaluation of the safety profile of adenovirus/Sleeping Beauty transposase hybrid-vectors. The obtained information will be useful when designing future preclinical studies utilizing hybrid-vectors in small and large animal models.

Vectorization of nuclear codes 90-1

International Nuclear Information System (INIS)

Nonomiya, Iwao; Nemoto, Toshiyuki; Ishiguro, Misako; Harada, Hiroo; Hori, Takeo.

1990-09-01

The vectorization has been made for four codes: SONATINA-2V HTTR version, TRIDOSE, VIENUS, and SCRYU. SONATINA-2V HTTR version is a code for analyzing the dynamic behavior of fuel blocks in the vertical slice of the HTGR (High Temperature Gas-cooled Reactor) core under seismic perturbation, TRIDOSE is a code for calculating environmental tritium concentration and dose, VIENUS is a code for analyzing visco elastic stress of the fuel block of HTTR (High Temperature gas-cooled Test Reactor), and SCRYU is a thermal-hydraulics code with boundary fitted coordinate system. The total speedup ratio of the vectorized versions to the original scalar ones is 5.2 for SONATINA-2V HTTR version. 5.9 ∼ 6.9 for TRIDOSE, 6.7 for VIENUS, 7.6 for SCRYU, respectively. In this report, we describe outline of codes, techniques used for the vectorization, verification of computed results, and speedup effect on the vectorized codes. (author)

Dose-response tests and semi-field evaluation of lethal and sub-lethal effects of slow release pyriproxyfen granules (Sumilarv®0.5G) for the control of the malaria vectors Anopheles gambiae sensu lato.

Science.gov (United States)

Mbare, Oscar; Lindsay, Steven W; Fillinger, Ulrike

2013-03-14

Recently research has shown that larviciding can be an effective tool for integrated malaria vector control. Nevertheless, the uptake of this intervention has been hampered by the need to re-apply larvicides frequently. There is a need to explore persistent, environmentally friendly larvicides for malaria vector control to reduce intervention efforts and costs by reducing the frequency of application. In this study, the efficacy of a 0.5% pyriproxyfen granule (Surmilarv®0.5G, Sumitomo Chemicals) was assessed for the control of Anopheles gambiae sensu stricto and Anopheles arabiensis, the major malaria vectors in sub-Saharan Africa. Dose-response and standardized field tests were implemented following standard procedures of the World Health Organization's Pesticide Evaluation Scheme to determine: (i) the susceptibility of vectors to this formulation; (ii) the residual activity and appropriate retreatment schedule for field application; and, (iii) sub-lethal impacts on the number and viability of eggs laid by adults after exposure to Sumilarv®0.5G during larval development. Anopheles gambiae s.s. and An. arabiensis were highly susceptible to Sumilarv®0.5G. Estimated emergence inhibition (EI) values were very low and similar for both species. The minimum dosage that completely inhibited adult emergence was between 0.01-0.03 parts per million (ppm) active ingredient (ai). Compared to the untreated control, an application of 0.018 ppm ai prevented 85% (95% confidence interval (CI) 82%-88%) of adult emergence over six weeks under standardized field conditions. A fivefold increase in dosage of 0.09 ppm ai prevented 97% (95% CI 94%-98%) emergence. Significant sub-lethal effects were observed in the standardized field tests. Female An. gambiae s.s. that were exposed to 0.018 ppm ai as larvae laid 47% less eggs, and females exposed to 0.09 ppm ai laid 74% less eggs than females that were unexposed to the treatment. Furthermore, 77% of eggs laid by females exposed to 0

Reducing Dose Uncertainty for Spot-Scanning Proton Beam Therapy of Moving Tumors by Optimizing the Spot Delivery Sequence

International Nuclear Information System (INIS)

Li, Heng; Zhu, X. Ronald; Zhang, Xiaodong

2015-01-01

Purpose: To develop and validate a novel delivery strategy for reducing the respiratory motion–induced dose uncertainty of spot-scanning proton therapy. Methods and Materials: The spot delivery sequence was optimized to reduce dose uncertainty. The effectiveness of the delivery sequence optimization was evaluated using measurements and patient simulation. One hundred ninety-one 2-dimensional measurements using different delivery sequences of a single-layer uniform pattern were obtained with a detector array on a 1-dimensional moving platform. Intensity modulated proton therapy plans were generated for 10 lung cancer patients, and dose uncertainties for different delivery sequences were evaluated by simulation. Results: Without delivery sequence optimization, the maximum absolute dose error can be up to 97.2% in a single measurement, whereas the optimized delivery sequence results in a maximum absolute dose error of ≤11.8%. In patient simulation, the optimized delivery sequence reduces the mean of fractional maximum absolute dose error compared with the regular delivery sequence by 3.3% to 10.6% (32.5-68.0% relative reduction) for different patients. Conclusions: Optimizing the delivery sequence can reduce dose uncertainty due to respiratory motion in spot-scanning proton therapy, assuming the 4-dimensional CT is a true representation of the patients' breathing patterns.

Vector control of induction machines

CERN Document Server

Robyns, Benoit

2012-01-01

After a brief introduction to the main law of physics and fundamental concepts inherent in electromechanical conversion, ""Vector Control of Induction Machines"" introduces the standard mathematical models for induction machines - whichever rotor technology is used - as well as several squirrel-cage induction machine vector-control strategies. The use of causal ordering graphs allows systematization of the design stage, as well as standardization of the structure of control devices. ""Vector Control of Induction Machines"" suggests a unique approach aimed at reducing parameter sensitivity for

Reducing methods of patients exposed dose using auto exposure control system in digital radiography

Energy Technology Data Exchange (ETDEWEB)

Shin, Seong Gyu [Dept. of Diagnostic Radiology, Dong A University Medical Center, Busan (Korea, Republic of)

2013-06-15

This study was carried out to reduce patient dose through focus-detector distance, kilovoltage, and a combination of copper filters. In the C, L-spine lateral, Skull AP views were obtained by making changes of 60-100 kV in tube voltage and of 100-200 cm in focus-detector distance and by adding a copper filter when using an auto exposure control device in the digital radiography equipment. The incident dose showed 90 kV, 0.3 mmCu in C-spine lateral with 0.06 mGy under the condition of 200 cm; 100 kV, 0.3 mmCu with 0.40 mGy under the condition of 200 cm and 90 kV 0.3 mmCu in Skull AP with the lowest value of 0.24 mGy under the condition of 140 cm. It was observed that entrance surface dose decreased the most when was increased by 150 cm, 70 kV (C-spine lateral), 81 kV (L-spine lateral). It was also found out that as the between the focus-detector increased in the expansion of the video decreased but the difference was not significant when the distance was 180 cm or more. Skull AP showed the most reduction in the entrance surface dose when the tube voltage was changed by 80 kV, 0.1 mmCu, and 120 cm. Therefore, when using the automatic exposure control device, it is recommended to use the highest tube voltage if possible and to increase focus-detector distance at least by 150-200 cm in wall and 120-140 cm in table in consideration of the radiotechnologist's physical conditions, and to combine 0.1-0.3 mmCu and higher filters. It is thus expected to reduce patient dose by avoiding distortion of images and reducing the entrance surface dose.

Integration of irradiation with cytoplasmic incompatibility to facilitate a lymphatic filariasis vector elimination approach

Directory of Open Access Journals (Sweden)

Dobson Stephen L

2009-08-01

Full Text Available Abstract Background Mass drug administration (MDA is the emphasis of an ongoing global lymphatic filariasis (LF elimination program by the World Health Organization, in which the entire 'at risk' human population is treated annually with anti-filarial drugs. However, there is evidence that the MDA strategy may not be equally appropriate in all areas of LF transmission, leading to calls for the augmentation of MDA with anti-vector interventions. One potential augmentative intervention is the elimination of vectors via repeated inundative releases of male mosquitoes made cytoplasmically incompatible via an infection with Wolbachia bacteria. However, with a reduction in the vector population size, there is the risk that an accidental female release would permit the establishment of the incompatible Wolbachia infection type, resulting in population replacement instead of population elimination. To avoid the release of fertile females, we propose the exposure of release individuals to low doses of radiation to sterilize any accidentally released females, reducing the risk of population replacement. Results Aedes polynesiensis pupae of differing ages were irradiated to determine a radiation dose that results in sterility but that does not affect the survival and competitiveness of males. Laboratory assays demonstrate that males irradiated at a female sterilizing dosage of 40 Gy are equally competitive with un-irradiated males. No effect of irradiation on the ability of Wolbachia to affect egg hatch was observed. Conclusion An irradiation dose of 40 Gy is sufficient to cause female sterility, but has no observed negative effect on male fitness. The results support further development of this approach as a preventative measure against accidental population replacement.

Space Vector Modulation Technique to Reduce Leakage Current of a Transformerless Three-Phase Four-Leg Photovoltaic System

Directory of Open Access Journals (Sweden)

F. Hasanzad

2017-06-01

Full Text Available Photovoltaic systems integrated to the grid have received considerable attention around the world. They can be connected to the electrical grid via galvanic isolation (transformer or without it (transformerless. Despite making galvanic isolation, low frequency transformer increases size, cost and losses. On the other hand, transformerless PV systems increase the leakage current (common-mode current, (CMC through the parasitic capacitors of the PV array. Inverter topology and switching technique are the most important parameters the leakage current depends on. As there is no need to extra hardware for switching scheme modification, it's an economical method for reducing leakage current. This paper evaluates the effect of different space vector modulation techniques on leakage current for a two-level three-phase four-leg inverter used in PV system. It proposes an efficient space vector modulation method which decreases the leakage current to below the quantity specified in VDE-0126-1-1 standard. furthermore, some other characteristics of the space vector modulation schemes that have not been significantly discussed for four-leg inverter, are considered, such as, modulation index, switching actions per period, common-mode voltage (CMV, and total harmonic distortion (THD. An extend software simulation using MATLAB/Simulink is performed to verify the effectiveness of the modulation technique.

Suggestion of the manual exposure condition guideline for reducing patient dose in digital breast tomosynthesis

Energy Technology Data Exchange (ETDEWEB)

Hong, Eun Ae [Dept. of Radiology, Korea University Guro Hospital, Seoul (Korea, Republic of); Lee, In Ja [Dept. of Radiologic Technology, Dongnam Health University, Suwon (Korea, Republic of)

2016-12-15

The conditions after exposure to digital mammography and digital breast tomosynthesis were analyzed. The examinations for the ACR phantom were done using manual exposure, not auto exposure, to examine image discrimination and patient dose. As a result, the following results were derived: In the CC exposure , the kVp was 2kVp higher while mAs decreased to 58.6% for the 3D tomography. Such result showed an approximate decrease of 60mAs. At that time, the patients Average Glandular Dose (AGD) was 1.65mGy in 2D and 1.87mGy in 3D; thus, AGD of 3D was shown to have about 1.13 times higher. The result of the manual exposure revealed a reduced mAs of up to 80%; there was no effect in the assessment standard in terms of image discrimination, resulting in more than 10 points. When mAs was reduced to 80% in the manual exposure for ACR phantom, AGD was decreased to 0.66mGy. The diagnostic values of images were maintained and patients dose was reduced in the manual exposure in the AEC condition for 3D. Since the use of 3D has recently increased, using the manual exposure has been recommended in this study to improve the diagnostic value, while, simultaneously reducing patients dose.

Declining Prevalence of Disease Vectors Under Climate Change

Science.gov (United States)

Escobar, Luis E.; Romero-Alvarez, Daniel; Leon, Renato; Lepe-Lopez, Manuel A.; Craft, Meggan E.; Borbor-Cordova, Mercy J.; Svenning, Jens-Christian

2016-12-01

More than half of the world population is at risk of vector-borne diseases including dengue fever, chikungunya, zika, yellow fever, leishmaniasis, chagas disease, and malaria, with highest incidences in tropical regions. In Ecuador, vector-borne diseases are present from coastal and Amazonian regions to the Andes Mountains; however, a detailed characterization of the distribution of their vectors has never been carried out. We estimate the distribution of 14 vectors of the above vector-borne diseases under present-day and future climates. Our results consistently suggest that climate warming is likely threatening some vector species with extinction, locally or completely. These results suggest that climate change could reduce the burden of specific vector species. Other vector species are likely to shift and constrain their geographic range to the highlands in Ecuador potentially affecting novel areas and populations. These forecasts show the need for development of early prevention strategies for vector species currently absent in areas projected as suitable under future climate conditions. Informed interventions could reduce the risk of human exposure to vector species with distributional shifts, in response to current and future climate changes. Based on the mixed effects of future climate on human exposure to disease vectors, we argue that research on vector-borne diseases should be cross-scale and include climatic, demographic, and landscape factors, as well as forces facilitating disease transmission at fine scales.

Validation of SplitVectors Encoding for Quantitative Visualization of Large-Magnitude-Range Vector Fields.

Science.gov (United States)

Henan Zhao; Bryant, Garnett W; Griffin, Wesley; Terrill, Judith E; Jian Chen

2017-06-01

We designed and evaluated SplitVectors, a new vector field display approach to help scientists perform new discrimination tasks on large-magnitude-range scientific data shown in three-dimensional (3D) visualization environments. SplitVectors uses scientific notation to display vector magnitude, thus improving legibility. We present an empirical study comparing the SplitVectors approach with three other approaches - direct linear representation, logarithmic, and text display commonly used in scientific visualizations. Twenty participants performed three domain analysis tasks: reading numerical values (a discrimination task), finding the ratio between values (a discrimination task), and finding the larger of two vectors (a pattern detection task). Participants used both mono and stereo conditions. Our results suggest the following: (1) SplitVectors improve accuracy by about 10 times compared to linear mapping and by four times to logarithmic in discrimination tasks; (2) SplitVectors have no significant differences from the textual display approach, but reduce cluttering in the scene; (3) SplitVectors and textual display are less sensitive to data scale than linear and logarithmic approaches; (4) using logarithmic can be problematic as participants' confidence was as high as directly reading from the textual display, but their accuracy was poor; and (5) Stereoscopy improved performance, especially in more challenging discrimination tasks.

Lateral rectal shielding reduces late rectal morbidity after high dose three-dimensional conformal radiation therapy for clinically localized prostate cancer: further evidence for a dose effect

Energy Technology Data Exchange (ETDEWEB)

Lee, W Robert; Hanks, Gerald E; Hanlon, Alexandra; Schultheiss, Timothy E

1995-07-01

Purpose: Using conventional treatment methods for the treatment of clinically localized prostate cancer central axis doses must be limited to 65-70 Gy to prevent significant damage to nearby normal tissues. A fundamental hypothesis of three-dimensional conformal radiation therapy (3DCRT) is that, by defining the target organ(s) accurately in three dimensions, it is possible to deliver higher doses to the target without a significant increase in normal tissue complications. This study examines whether this hypothesis holds true and whether a simple modification of treatment technique can reduce the incidence of late rectal morbidity in patients with prostate cancer treated with 3DCRT to minimum planning target volume (PTV) doses of 71-75 Gy. Materials and Methods: 257 patients with clinically localized prostate cancer completed 3DCRT by December 31, 1993 and received a minimum PTV dose of 71-75 Gy. The median follow-up time was 22 months (range 4-67 months) and 98% of patients had followup of longer than 12 months. The calculated dose at the center of the prostate was <74 Gy in 19 patients, 74-76 Gy in 206 patients and >76 Gy in 32 patients. Late rectal morbidity was graded according to the LENT scoring system. Eighty-eight consecutive patients were treated with a rectal block added to the lateral fields. In these patients the posterior margin from the prostate to the block edge was reduced from the standard 15 mm to 7.5 mm for the final 10 Gy which reduced the dose to portions of the anterior rectal wall by approximately 4-5 Gy. Estimates of rates for rectal morbidity were determined by Kaplan-Meier actuarial analyses. Differences in morbidity percentages were evaluated by the Pearson chi square test. Results: Grade 2-3 rectal morbidity developed in 46 of 257 patients (18%) and in the majority of cases consisted of rectal bleeding. No patient has developed grade 4 or 5 rectal morbidity. The actuarial rate of grade 2-3 morbidity is 22% at 24 months and the median

Vector rectangular-shape laser based on reduced graphene oxide interacting with a long fiber taper.

Science.gov (United States)

Gao, Lei; Zhu, Tao; Huang, Wei; Zeng, Jing

2014-10-01

A vector dual-wavelength rectangular-shape laser (RSL) based on a long fiber taper deposited with reduced graphene oxide is proposed, where nonlinearity is enhanced due to a large evanescent-field-interacting length and strong field confinement of an 8 mm fiber taper with a waist diameter of 4 μm. Graphene flakes are deposited uniformly on the taper waist with light pressure effect, so this structure guarantees both excellent saturable absorption and high nonlinearity. The RSL with a repetition rate of 7.9 MHz shows fast polarization switching in two orthogonal polarization directions, and temporal and spectral characteristics are investigated.

The usefulness of Al face block fabrication for reducing exposure dose of thyroid glands in mammography

Energy Technology Data Exchange (ETDEWEB)

Hong, Eun Ae [Dept. of Diagnostic Radiology, Korea University Guro Hospital, Seoul (Korea, Republic of); Lee, In Ja [Dept. of Radiologic Technology, Dongnam Health College, Suwon (Korea, Republic of)

2013-03-15

Currently, there are many studies being conducted around the world to reduce exposure dose to radiation for patients to receive medical treatments in a safe environment. We developed and fabricated of this shield that the patients are protected from the radiation and are need of safety control during breast imaging. In this study, for breast imaging, GE Senography 2000D were used and set at SID 65 cm, 28 kVp, and 63 mAs. The measuring instrument was Flukes Victoreen 6000-529. And we performed Face Block on with 30 patients. The chamber on the actual thyroid glands to take CC and MLO and measure the dosage before and after wearing the Face Block. For the results, after wearing the Face Block, exposure was decreased by 53.8%-100% and 65.8% in average in CC View and by 50%-100% and 60.7% in average in MLO View. The development of the Face Block that practically decreased the exposure dose of thyroid glands, crystalline eyes during breast imaging and reduced the patients anxiety during breast imaging. The Face Block is expected to improve patients satisfaction and contribute to reducing patients exposure dose, but more efforts should be made to reduce exposure dose to medical radiation.

Analysis of technologies and experiences for reducing occupational radiation dose and study for applying to regulations

Energy Technology Data Exchange (ETDEWEB)

Moon, Joo Hyun; Park, Moon Soo; Lee, Un Jang; Song, Jae Hyuk; Kim, Byeong Soo; Kim, Chong Uk [Seoul National Univ., Seoul (Korea, Republic of)

2003-01-15

To reduce Occupational Radiation Dose (ORD) effectively and enhance the radiological safety, the comprehensive assessment of the experiences to reduce ORD should be made by regulatory body as well as utilities. Hence, the objective of this study is to assess the experiences for reducing ORD from the regulatory viewpoint. With the research objective, the followings are performed in this research; analysis of occupational dose trends at domestic and foreign NPPs, identification of the effective technologies for reducing ORD, examination of the effects of the technologies for reducing ORD, derivation of the regulatory means for implementing he research results. From this study, the regulatory means for effective reduction of ORD are derived. Hence, the results can be utilized as a basic materials for ALARA requirements.

Efficacy of reduced dose of intravitreal triamcinolone acetonide in a case of active serpiginous choroiditis

Directory of Open Access Journals (Sweden)

Avirupa Ghose

2016-01-01

Full Text Available Active serpiginous choroiditis (SC is a vision-threatening condition which requires intensive treatment using corticosteroids and/or immunosuppressives, especially if the lesions are involving or encroaching on the macula. Use of oral and intravenous high-dose steroids are contraindicated in uncontrolled diabetics. Intravitreal steroid delivers a localized dose in such situations. This case report highlights the efficacy of reduced dose of intravitreal triamcinolone acetonide (2 mg in the treatment of active SC.

Head CT: Image quality improvement with ASIR-V using a reduced radiation dose protocol for children.

Science.gov (United States)

Kim, Hyun Gi; Lee, Ho-Joon; Lee, Seung-Koo; Kim, Hyun Ji; Kim, Myung-Joon

2017-09-01

To investigate the quality of images reconstructed with adaptive statistical iterative reconstruction V (ASIR-V), using pediatric head CT protocols. A phantom was scanned at decreasing 20% mA intervals using our standard pediatric head CT protocols. Each study was then reconstructed at 10% ASIR-V intervals. After the phantom study, we reduced mA by 10% in the protocol for ASIR-V and by 30% in the protocol for 3- to 15-year-old patients and applied 40% ASIR-V. Increasing the percentage of ASIR-V resulted in lower noise and higher contrast-to-noise ratio (CNR) and preserved spatial resolution in the phantom study. Compared to a conventional-protocol, reduced-dose protocol with ASIR-V achieved 12.8% to 34.0% of dose reduction and showed images of lower noise (9.22 vs. 10.73, P = 0.043) and higher CNR in different levels (centrum semiovale, 2.14 vs. 1.52, P = 0.003; basal ganglia, 1.46 vs. 1.07, P = 0.001; and cerebellum, 2.18 vs. 1.33, P ASIR-V. Use of ASIR-V allowed a 12.8% to 34.0% dose reduction in each age group with potential to improve image quality. • It is possible to reduce radiation dose and improve image quality with ASIR-V. • We improved noise and CNR and decreased radiation dose. • Sharpness improved with ASIR-V. • Total radiation dose was decreased by 12.8% to 34.0%.

On the Reduction of Vector and Axial-Vector Fields in a Meson Effective Action at O(p4)

International Nuclear Information System (INIS)

Bel'kov, A.A.; Lanev, A.V.; Schaale, A.

1994-01-01

Starting from an effective NJL-type quark interaction we have derived an effective meson action for the pseudoscalar sector. The vector and axial-vector degrees of freedom have been integrated out, applying the static equations of motion. As the results we have found a (reduced) pseudoscalar meson Lagrangian of the Gasser-Leutwyler type with modified structure coefficients L i . This method has been also used to construct the reduced weak and electromagnetic-weak currents. The application of the reduced Lagrangian and currents has been considered in physical processes. 36 refs., 1 fig., 1 tab

Agricultural measures to reduce radiation doses to man caused by severe nuclear accidents

International Nuclear Information System (INIS)

Dorp, F. van; Eleveld, R.; Frissel, M.J.

1981-01-01

Agricultural land and products may become contaminated after a severe nuclear accident. If radiation doses to man caused by the ingestion of contaminated agricultural products from such areas will be unacceptably high, measures to reduce this radiation dose will have to be taken. Radiation doses to man can be estimated by using models which describe quantitatively the transfer of radionuclides through the biosphere. The following processes and pathways are described in this study: accidental releases into atmospheric environments and subsequent nearby deposition; contamination of crops by direct deposition and the subsequent short term pathway (e.g. grass-cow-milk-man); contamination of soil and the subsequent long term pathway (e.g. soil-crop-man, soil-grass-cattle-milk/meat-man). Depending on the degree of contamination and on the estimated radiation doses to man, various measures are advised. (Auth.)

The leaded apron revisited: does it reduce gonadal radiation dose in dental radiology

Energy Technology Data Exchange (ETDEWEB)

Wood, R.E.; Harris, A.M.; van der Merwe, E.J.; Nortje, C.J. (Ontario Cancer Institute, Princess Margaret Hospital, Toronto (Canada))

1991-05-01

A tissue-equivalent anthropomorphic human phantom was used with a lithium fluoride thermoluminescent dosimetry system to evaluate the radiation absorbed dose to the ovarian and testicular region during dental radiologic procedures. Measurements were made with and without personal lead shielding devices consisting of thyroid collar and apron of 0.25 mm lead thickness equivalence. The radiation absorbed dose with or without lead shielding did not differ significantly from control dosimeters in vertex occlusal and periapical views (p greater than 0.05). Personal lead shielding devices did reduce gonadal dose in the case of accidental exposure (p less than 0.05). A leaded apron of 0.25 mm lead thickness equivalent was permeable to radiation in direct exposure testing.

The leaded apron revisited: does it reduce gonadal radiation dose in dental radiology

International Nuclear Information System (INIS)

Wood, R.E.; Harris, A.M.; van der Merwe, E.J.; Nortje, C.J.

1991-01-01

A tissue-equivalent anthropomorphic human phantom was used with a lithium fluoride thermoluminescent dosimetry system to evaluate the radiation absorbed dose to the ovarian and testicular region during dental radiologic procedures. Measurements were made with and without personal lead shielding devices consisting of thyroid collar and apron of 0.25 mm lead thickness equivalence. The radiation absorbed dose with or without lead shielding did not differ significantly from control dosimeters in vertex occlusal and periapical views (p greater than 0.05). Personal lead shielding devices did reduce gonadal dose in the case of accidental exposure (p less than 0.05). A leaded apron of 0.25 mm lead thickness equivalent was permeable to radiation in direct exposure testing

Disruption of Vector Host Preference with Plant Volatiles May Reduce Spread of Insect-Transmitted Plant Pathogens.

Science.gov (United States)

Martini, Xavier; Willett, Denis S; Kuhns, Emily H; Stelinski, Lukasz L

2016-05-01

Plant pathogens can manipulate the odor of their host; the odor of an infected plant is often attractive to the plant pathogen vector. It has been suggested that this odor-mediated manipulation attracts vectors and may contribute to spread of disease; however, this requires further broad demonstration among vector-pathogen systems. In addition, disruption of this indirect chemical communication between the pathogen and the vector has not been attempted. We present a model that demonstrates how a phytophathogen (Candidatus Liberibacter asiaticus) can increase its spread by indirectly manipulating the behavior of its vector (Asian citrus psyllid, Diaphorina citri Kuwayama). The model indicates that when vectors are attracted to pathogen-infected hosts, the proportion of infected vectors increases, as well as, the proportion of infected hosts. Additionally, the peak of infected host populations occurs earlier as compared with controls. These changes in disease dynamics were more important during scenarios with higher vector mortality. Subsequently, we conducted a series of experiments to disrupt the behavior of the Asian citrus psyllid. To do so, we exposed the vector to methyl salicylate, the major compound released following host infection with the pathogen. We observed that during exposure or after pre-exposure to methyl salicylate, the host preference can be altered; indeed, the Asian citrus psyllids were unable to select infected hosts over uninfected counterparts. We suggest mechanisms to explain these interactions and potential applications of disrupting herbivore host preference with plant volatiles for sustainable management of insect vectors.

Neonatal Gene Therapy for Hemophilia B by a Novel Adenovirus Vector Showing Reduced Leaky Expression of Viral Genes.

Science.gov (United States)

Iizuka, Shunsuke; Sakurai, Fuminori; Tachibana, Masashi; Ohashi, Kazuo; Mizuguchi, Hiroyuki

2017-09-15

Gene therapy during neonatal and infant stages is a promising approach for hemophilia B, a congenital disorder caused by deficiency of blood coagulation factor IX (FIX). An adenovirus (Ad) vector has high potential for use in neonatal or infant gene therapy for hemophilia B due to its superior transduction properties; however, leaky expression of Ad genes often reduces the transduction efficiencies by Ad protein-mediated tissue damage. Here, we used a novel Ad vector, Ad-E4-122aT, which exhibits a reduction in the leaky expression of Ad genes in liver, in gene therapy studies for neonatal hemophilia B mice. Ad-E4-122aT exhibited significantly higher transduction efficiencies than a conventional Ad vector in neonatal mice. In neonatal hemophilia B mice, a single neonatal injection of Ad-E4-122aT expressing human FIX (hFIX) (Ad-E4-122aT-AHAFIX) maintained more than 6% of the normal plasma hFIX activity levels for approximately 100 days. Sequential administration of Ad-E4-122aT-AHAFIX resulted in more than 100% of the plasma hFIX activity levels for more than 100 days and rescued the bleeding phenotypes of hemophilia B mice. In addition, immunotolerance to hFIX was induced by Ad-E4-122aT-AHAFIX administration in neonatal hemophilia B mice. These results indicated that Ad-E4-122aT is a promising gene delivery vector for neonatal or infant gene therapy for hemophilia B.

Lateral topography for reducing effective dose in low-dose chest CT.

Science.gov (United States)

Bang, Dong-Ho; Lim, Daekeon; Hwang, Wi-Sub; Park, Seong-Hoon; Jeong, Ok-man; Kang, Kyung Wook; Kang, Hohyung

2013-06-01

The purposes of this study were to assess radiation exposure during low-dose chest CT by using lateral topography and to compare the lateral topographic findings with findings obtained with anteroposterior topography alone and anteroposterior and lateral topography combined. From November 2011 to February 2012, 210 male subjects were enrolled in the study. Age, weight, and height of the men were recorded. All subjects were placed into one of three subgroups based on the type of topographic image obtained: anteroposterior topography, lateral topography, and both anteroposterior and lateral topography. Imaging was performed with a 128-MDCT scanner. CT, except for topography, was the same for all subjects. A radiologist analyzed each image, recorded scan length, checked for any insufficiencies in the FOV, and calculated the effective radiation dose. One-way analysis of variance and multiple comparisons were used to compare the effective radiation exposure and scan length between groups. The mean scan length in the anteroposterior topography group was significantly greater than that of the lateral topography group and the combined anteroposterior and lateral topography group (p topography group (0.735 ± 0.033 mSv) was significantly lower than that for the anteroposterior topography group (0.763 ± 0.038 mSv) and the combined anteroposterior and lateral topography group (0.773 ± 0.038) (p < 0.001). Lateral topographic low-dose CT was associated with a lower effective radiation dose and scan length than either anteroposterior topographic low-dose chest CT or low-dose chest CT with both anteroposterior and lateral topograms.

Diagnostic performance of reduced-dose CT with a hybrid iterative reconstruction algorithm for the detection of hypervascular liver lesions: a phantom study

Energy Technology Data Exchange (ETDEWEB)

Nakamoto, Atsushi; Tanaka, Yoshikazu; Juri, Hiroshi; Nakai, Go; Narumi, Yoshifumi [Osaka Medical College, Department of Radiology, Takatsuki, Osaka (Japan); Yoshikawa, Shushi [Osaka Medical College Hospital, Central Radiology Department, Takatsuki, Osaka (Japan)

2017-07-15

To investigate the diagnostic performance of reduced-dose CT with a hybrid iterative reconstruction (IR) algorithm for the detection of hypervascular liver lesions. Thirty liver phantoms with or without simulated hypervascular lesions were scanned with a 320-slice CT scanner with control-dose (40 mAs) and reduced-dose (30 and 20 mAs) settings. Control-dose images were reconstructed with filtered back projection (FBP), and reduced-dose images were reconstructed with FBP and a hybrid IR algorithm. Objective image noise and the lesion to liver contrast-to-noise ratio (CNR) were evaluated quantitatively. Images were interpreted independently by 2 blinded radiologists, and jackknife alternative free-response receiver-operating characteristic (JAFROC) analysis was performed. Hybrid IR images with reduced-dose settings (both 30 and 20 mAs) yielded significantly lower objective image noise and higher CNR than control-dose FBP images (P <.05). However, hybrid IR images with reduced-dose settings had lower JAFROC1 figure of merit than control-dose FBP images, although only the difference between 20 mAs images and control-dose FBP images was significant for both readers (P <.01). An aggressive reduction of the radiation dose would impair the detectability of hypervascular liver lesions, although objective image noise and CNR would be preserved by a hybrid IR algorithm. (orig.)

Vectorization, parallelization and porting of nuclear codes on the VPP500 system (vectorization). Progress report fiscal 1997

International Nuclear Information System (INIS)

Kawasaki, Nobuo; Ogasawara, Shinobu; Adachi, Masaaki; Kume, Etsuo; Ishizuki, Shigeru; Tanabe, Hidenobu; Nemoto, Toshiyuki; Kawai, Wataru; Watanabe, Hideo

1999-05-01

Several computer codes in the nuclear field have been vectorized, parallelized and transported on the FUJITSU VPP500 system and/or the AP3000 system at Center for Promotion of Computational Science and Engineering in Japan Atomic Energy Research Institute. We dealt with 14 codes in fiscal 1997. These results are reported in 3 parts, i.e., the vectorization part, the parallelization part and the porting part. In this report, we describe the vectorization. In this vectorization part, the vectorization of multidimensional two-fluid model code ACE-3D for evaluation of constitutive equations, statistical decay code SD and three-dimensional thermal analysis code for in-core test section (T2) of HENDEL SSPHEAT are described. In the parallelization part, the parallelization of cylindrical direct numerical simulation code CYLDNS44N, worldwide version of system for prediction of environmental emergency dose information code WSPEEDI, extension of quantum molecular dynamics code EQMD and three-dimensional non-steady compressible fluid dynamics code STREAM are described. In the porting part, the porting of transient reactor analysis code TRAC-BF1 and Monte Carlo radiation transport code MCNP4A on the AP3000 are described. In addition, a modification of program libraries for command-driven interactive data analysis plotting program IPLOT is described. (author)

Predicted altitudinal shifts and reduced spatial distribution of Leishmania infantum vector species under climate change scenarios in Colombia.

Science.gov (United States)

González, Camila; Paz, Andrea; Ferro, Cristina

2014-01-01

. longipalpis and confining L. evansi to certain regions in the Caribbean Coast. Altitudinal shifts have been reported for cutaneous leishmaniasis vectors in Colombia and Peru. Here, we predict the same outcome for VL vectors in Colombia. Changes in spatial distribution patterns could be affecting local abundances due to climatic pressures on vector populations thus reducing the incidence of human cases. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Reduced oxygen enhancement ratio at low doses

International Nuclear Information System (INIS)

Palcic, B.; Skarsgard, L.D.

1984-01-01

The oxygen depletion rate in cell suspensions was measured using a Clark electrode. It was found that under experimental conditions used in this laboratory for hypoxic irradiations, the oxygen levels before the start of irradiation are always below 0.1μm, the levels which could give any significant enhancement to radiation inactivation by x-rays. The measured O/sub 2/ depletion rates were comparable to those reported in the literature. Chinese hamster cells (CHO) were made hypoxic by gas exchange, combined with metabolic consumption of oxygen by cells at 37 0 C. Full survival curves were determined in the dose range 0 to 3Gy using the low dose survival assay. The results confirmed the authors' earlier finding that the OER decreases at low doses. The authors therefore believe that the dose-dependent OER is a true radiobiological phenomenon and not an artifact of the experimental method used in the low dose survival assay

Conformal Killing vectors in Robertson-Walker spacetimes

International Nuclear Information System (INIS)

Maartens, R.; Maharaj, S.d.

1986-01-01

It is well known that Robertson-Walker spacetimes admit a conformal Killingl vector normal to the spacelike homogeneous hypersurfaces. Because these spacetimes are conformally flat, there are a further eight conformal Killing vectors, which are neither normal nor tangent to the homogeneous hypersurfaces. The authors find these further conformal Killing vectors and the Lie algebra of the full G 15 of conformal motions. Conditions on the metric scale factor are determined which reduce some of the conformal Killing vectors to homothetic Killing vectors or Killing vectors, allowing one to regain in a unified way the known special geometries. The non-normal conformal Killing vectors provide a counter-example to show that conformal motions do not, in general, map a fluid flow conformally. These non-normal vectors are also used to find the general solution of the null geodesic equation and photon Liouville equation. (author)

Iterative reconstruction technique with reduced volume CT dose index: diagnostic accuracy in pediatric acute appendicitis

International Nuclear Information System (INIS)

Didier, Ryne A.; Vajtai, Petra L.; Hopkins, Katharine L.

2015-01-01

Iterative reconstruction technique has been proposed as a means of reducing patient radiation dose in pediatric CT. Yet, the effect of such reductions on diagnostic accuracy has not been thoroughly evaluated. This study compares accuracy of diagnosing pediatric acute appendicitis using contrast-enhanced abdominopelvic CT scans performed with traditional pediatric weight-based protocols and filtered back projection reconstruction vs. a filtered back projection/iterative reconstruction technique blend with reduced volume CT dose index (CTDI vol ). Results of pediatric contrast-enhanced abdominopelvic CT scans done for pain and/or suspected appendicitis were reviewed in two groups: A, 192 scans performed with the hospital's established weight-based CT protocols and filtered back projection reconstruction; B, 194 scans performed with iterative reconstruction technique and reduced CTDI vol . Reduced CTDI vol was achieved primarily by reductions in effective tube current-time product (mAs eff ) and tube peak kilovoltage (kVp). CT interpretation was correlated with clinical follow-up and/or surgical pathology. CTDI vol , size-specific dose estimates (SSDE) and performance characteristics of the two CT techniques were then compared. Between groups A and B, mean CTDI vol was reduced by 45%, and mean SSDE was reduced by 46%. Sensitivity, specificity and diagnostic accuracy were 96%, 97% and 96% in group A vs. 100%, 99% and 99% in group B. Accuracy in diagnosing pediatric acute appendicitis was maintained in contrast-enhanced abdominopelvic CT scans that incorporated iterative reconstruction technique, despite reductions in mean CTDI vol and SSDE by nearly half as compared to the hospital's traditional weight-based protocols. (orig.)

Reirradiation of Large-Volume Recurrent Glioma With Pulsed Reduced-Dose-Rate Radiotherapy

International Nuclear Information System (INIS)

Adkison, Jarrod B.; Tome, Wolfgang; Seo, Songwon; Richards, Gregory M.; Robins, H. Ian; Rassmussen, Karl; Welsh, James S.; Mahler, Peter A.; Howard, Steven P.

2011-01-01

Purpose: Pulsed reduced-dose-rate radiotherapy (PRDR) is a reirradiation technique that reduces the effective dose rate and increases the treatment time, allowing sublethal damage repair during irradiation. Patients and Methods: A total of 103 patients with recurrent glioma underwent reirradiation using PRDR (86 considered to have Grade 4 at PRDR). PRDR was delivered using a series of 0.2-Gy pulses at 3-min intervals, creating an apparent dose rate of 0.0667 Gy/min to a median dose of 50 Gy (range, 20-60) delivered in 1.8-2.0-Gy fractions. The mean treatment volume was 403.5 ± 189.4 cm 3 according to T 2 -weighted magnetic resonance imaging and a 2-cm margin. Results: For the initial or upgraded Grade 4 cohort (n = 86), the median interval from the first irradiation to PRDR was 14 months. Patients undergoing PRDR within 14 months of the first irradiation (n = 43) had a median survival of 21 weeks. Those treated ≥14 months after radiotherapy had a median survival of 28 weeks (n = 43; p = 0.004 and HR = 1.82 with a 95% CI ranging from 1.25 to 3.10). These data compared favorably to historical data sets, because only 16% of the patients were treated at first relapse (with 46% treated at the second relapse, 32% at the third or fourth relapse, and 4% at the fourth or fifth relapse). The median survival since diagnosis and retreatment was 6.3 years and 11.4 months for low-grade, 4.1 years and 5.6 months for Grade 3, and 1.6 years and 5.1 months for Grade 4 tumors, respectively, according to the initial histologic findings. Multivariate analysis revealed age at the initial diagnosis, initial low-grade disease, and Karnofsky performance score of ≥80 to be significant predictors of survival after initiation of PRDR. Conclusion: PRDR allowed for safe retreatment of larger volumes to high doses with palliative benefit.

Local Patch Vectors Encoded by Fisher Vectors for Image Classification

Directory of Open Access Journals (Sweden)

Shuangshuang Chen

2018-02-01

Full Text Available The objective of this work is image classification, whose purpose is to group images into corresponding semantic categories. Four contributions are made as follows: (i For computational simplicity and efficiency, we directly adopt raw image patch vectors as local descriptors encoded by Fisher vector (FV subsequently; (ii For obtaining representative local features within the FV encoding framework, we compare and analyze three typical sampling strategies: random sampling, saliency-based sampling and dense sampling; (iii In order to embed both global and local spatial information into local features, we construct an improved spatial geometry structure which shows good performance; (iv For reducing the storage and CPU costs of high dimensional vectors, we adopt a new feature selection method based on supervised mutual information (MI, which chooses features by an importance sorting algorithm. We report experimental results on dataset STL-10. It shows very promising performance with this simple and efficient framework compared to conventional methods.

Support-Vector-Machine-Based Reduced-Order Model for Limit Cycle Oscillation Prediction of Nonlinear Aeroelastic System

Directory of Open Access Journals (Sweden)

Gang Chen

2012-01-01

Full Text Available It is not easy for the system identification-based reduced-order model (ROM and even eigenmode based reduced-order model to predict the limit cycle oscillation generated by the nonlinear unsteady aerodynamics. Most of these traditional ROMs are sensitive to the flow parameter variation. In order to deal with this problem, a support vector machine- (SVM- based ROM was investigated and the general construction framework was proposed. The two-DOF aeroelastic system for the NACA 64A010 airfoil in transonic flow was then demonstrated for the new SVM-based ROM. The simulation results show that the new ROM can capture the LCO behavior of the nonlinear aeroelastic system with good accuracy and high efficiency. The robustness and computational efficiency of the SVM-based ROM would provide a promising tool for real-time flight simulation including nonlinear aeroelastic effects.

Anti-dengue efficacy of bioactive andrographolide from Andrographis paniculata (Lamiales: Acanthaceae) against the primary dengue vector Aedes aegypti (Diptera: Culicidae).

Science.gov (United States)

Edwin, Edward-Sam; Vasantha-Srinivasan, Prabhakaran; Senthil-Nathan, Sengottayan; Thanigaivel, Annamalai; Ponsankar, Athirstam; Pradeepa, Venkatraman; Selin-Rani, Selvaraj; Kalaivani, Kandaswamy; Hunter, Wayne B; Abdel-Megeed, Ahmed; Duraipandiyan, Veeramuthu; Al-Dhabi, Naif Abdullah

2016-11-01

The current study investigated the toxic effect of the leaf extract compound andrographolide from Andrographis paniculata (Burm.f) against the dengue vector Ae. aegypti. GC-MS analysis revealed that andrographolide was recognized as the major chemical constituent with the prominent peak area compared with other compounds. All isolated toxic compounds were purified and confirmed through RP-HPLC against chemical standards. The larvicidal assays established at 25ppm of bioactive compound against the treated instars of Ae. Aegypti showed prominent mortality compared to other treated concentrations. The percent mortality of larvae was directly proportional to concentration. The lethal concentration (LC50) was observed at 12ppm treatment concentration. The bioactive andrographolide considerably reduced the detoxifying enzyme regulations of α- and β- carboxylesterases. In contrast, the levels of GST and CYP450 significantly increase in a dose dependent manner. The andrographolide also showed strong oviposition deterrence effects at the sub-lethal dose of 12ppm. Similarly, the mean number of eggs were also significantly reduced in a dose dependent manner. At the concentration of 12ppm the effective percentage of repellency was greater than 90% with a protection time of 15-210min, compared with control. The histopathology study displayed that larvae treated with bioactive andrographolide had cytopathic effects in the midgut epithelium compared with the control. The present study established that bioactive andrographolide served as a potential useful for dengue vector management. Copyright © 2016 Elsevier B.V. All rights reserved.

Vector-model-supported optimization in volumetric-modulated arc stereotactic radiotherapy planning for brain metastasis

International Nuclear Information System (INIS)

Liu, Eva Sau Fan; Wu, Vincent Wing Cheung; Harris, Benjamin; Foote, Matthew; Lehman, Margot; Chan, Lawrence Wing Chi

2017-01-01

Long planning time in volumetric-modulated arc stereotactic radiotherapy (VMA-SRT) cases can limit its clinical efficiency and use. A vector model could retrieve previously successful radiotherapy cases that share various common anatomic features with the current case. The prsent study aimed to develop a vector model that could reduce planning time by applying the optimization parameters from those retrieved reference cases. Thirty-six VMA-SRT cases of brain metastasis (gender, male [n = 23], female [n = 13]; age range, 32 to 81 years old) were collected and used as a reference database. Another 10 VMA-SRT cases were planned with both conventional optimization and vector-model-supported optimization, following the oncologists' clinical dose prescriptions. Planning time and plan quality measures were compared using the 2-sided paired Wilcoxon signed rank test with a significance level of 0.05, with positive false discovery rate (pFDR) of less than 0.05. With vector-model-supported optimization, there was a significant reduction in the median planning time, a 40% reduction from 3.7 to 2.2 hours (p = 0.002, pFDR = 0.032), and for the number of iterations, a 30% reduction from 8.5 to 6.0 (p = 0.006, pFDR = 0.047). The quality of plans from both approaches was comparable. From these preliminary results, vector-model-supported optimization can expedite the optimization of VMA-SRT for brain metastasis while maintaining plan quality.

Vector-model-supported optimization in volumetric-modulated arc stereotactic radiotherapy planning for brain metastasis

Energy Technology Data Exchange (ETDEWEB)

Liu, Eva Sau Fan [Department of Radiation Oncology, Princess Alexandra Hospital, Brisbane (Australia); Department of Health Technology and Informatics, The Hong Kong Polytechnic University (Hong Kong); Wu, Vincent Wing Cheung [Department of Health Technology and Informatics, The Hong Kong Polytechnic University (Hong Kong); Harris, Benjamin [Department of Radiation Oncology, Princess Alexandra Hospital, Brisbane (Australia); Foote, Matthew; Lehman, Margot [Department of Radiation Oncology, Princess Alexandra Hospital, Brisbane (Australia); School of Medicine, University of Queensland (Australia); Chan, Lawrence Wing Chi, E-mail: wing.chi.chan@polyu.edu.hk [Department of Health Technology and Informatics, The Hong Kong Polytechnic University (Hong Kong)

2017-07-01

Long planning time in volumetric-modulated arc stereotactic radiotherapy (VMA-SRT) cases can limit its clinical efficiency and use. A vector model could retrieve previously successful radiotherapy cases that share various common anatomic features with the current case. The prsent study aimed to develop a vector model that could reduce planning time by applying the optimization parameters from those retrieved reference cases. Thirty-six VMA-SRT cases of brain metastasis (gender, male [n = 23], female [n = 13]; age range, 32 to 81 years old) were collected and used as a reference database. Another 10 VMA-SRT cases were planned with both conventional optimization and vector-model-supported optimization, following the oncologists' clinical dose prescriptions. Planning time and plan quality measures were compared using the 2-sided paired Wilcoxon signed rank test with a significance level of 0.05, with positive false discovery rate (pFDR) of less than 0.05. With vector-model-supported optimization, there was a significant reduction in the median planning time, a 40% reduction from 3.7 to 2.2 hours (p = 0.002, pFDR = 0.032), and for the number of iterations, a 30% reduction from 8.5 to 6.0 (p = 0.006, pFDR = 0.047). The quality of plans from both approaches was comparable. From these preliminary results, vector-model-supported optimization can expedite the optimization of VMA-SRT for brain metastasis while maintaining plan quality.

Effects of Zika Virus Strain and Aedes Mosquito Species on Vector Competence

Science.gov (United States)

Bialosuknia, Sean M.; Zink, Steven D.; Brecher, Matthew; Ehrbar, Dylan J.; Morrissette, Madeline N.; Kramer, Laura D.

2017-01-01

In the Western Hemisphere, Zika virus is thought to be transmitted primarily by Aedes aegypti mosquitoes. To determine the extent to which Ae. albopictus mosquitoes from the United States are capable of transmitting Zika virus and the influence of virus dose, virus strain, and mosquito species on vector competence, we evaluated multiple doses of representative Zika virus strains in Ae. aegypti and Ae. albopictus mosquitoes. Virus preparation (fresh vs. frozen) significantly affected virus infectivity in mosquitoes. We calculated 50% infectious doses to be 6.1–7.5 log10 PFU/mL; minimum infective dose was 4.2 log10 PFU/mL. Ae. albopictus mosquitoes were more susceptible to infection than Ae. aegypti mosquitoes, but transmission efficiency was higher for Ae. aegypti mosquitoes, indicating a transmission barrier in Ae. albopictus mosquitoes. Results suggest that, although Zika virus transmission is relatively inefficient overall and dependent on virus strain and mosquito species, Ae. albopictus mosquitoes could become major vectors in the Americas. PMID:28430564

Effects of Zika Virus Strain and Aedes Mosquito Species on Vector Competence.

Science.gov (United States)

Ciota, Alexander T; Bialosuknia, Sean M; Zink, Steven D; Brecher, Matthew; Ehrbar, Dylan J; Morrissette, Madeline N; Kramer, Laura D

2017-07-01

In the Western Hemisphere, Zika virus is thought to be transmitted primarily by Aedes aegypti mosquitoes. To determine the extent to which Ae. albopictus mosquitoes from the United States are capable of transmitting Zika virus and the influence of virus dose, virus strain, and mosquito species on vector competence, we evaluated multiple doses of representative Zika virus strains in Ae. aegypti and Ae. albopictus mosquitoes. Virus preparation (fresh vs. frozen) significantly affected virus infectivity in mosquitoes. We calculated 50% infectious doses to be 6.1-7.5 log 10 PFU/mL; minimum infective dose was 4.2 log 10 PFU/mL. Ae. albopictus mosquitoes were more susceptible to infection than Ae. aegypti mosquitoes, but transmission efficiency was higher for Ae. aegypti mosquitoes, indicating a transmission barrier in Ae. albopictus mosquitoes. Results suggest that, although Zika virus transmission is relatively inefficient overall and dependent on virus strain and mosquito species, Ae. albopictus mosquitoes could become major vectors in the Americas.

Low-Dose Dextromethorphan, a NADPH Oxidase Inhibitor, Reduces Blood Pressure and Enhances Vascular Protection in Experimental Hypertension

Science.gov (United States)

Wu, Tao-Cheng; Chao, Chih-Yu; Lin, Shing-Jong; Chen, Jaw-Wen

2012-01-01

Background Vascular oxidative stress may be increased with age and aggravate endothelial dysfunction and vascular injury in hypertension. This study aimed to investigate the effects of dextromethorphan (DM), a NADPH oxidase inhibitor, either alone or in combination treatment, on blood pressure (BP) and vascular protection in aged spontaneous hypertensive rats (SHRs). Methodology/Principal Findings Eighteen-week-old WKY rats and SHRs were housed for 2 weeks. SHRs were randomly assigned to one of the 12 groups: untreated; DM monotherapy with 1, 5 or 25 mg/kg/day; amlodipine (AM, a calcium channel blocker) monotherapy with 1 or 5 mg/kg/day; and combination therapy of DM 1, 5 or 25 mg/kg/day with AM 1 or 5 mg/kg/day individually for 4 weeks. The in vitro effects of DM were also examined. In SHRs, AM monotherapy dose-dependently reduced arterial systolic BP. DM in various doses significantly and similarly reduced arterial systolic BP. Combination of DM with AM gave additive effects on BP reduction. DM, either alone or in combination with AM, improved aortic endothelial function indicated by ex vivo acetylcholine-induced relaxation. The combination of low-dose DM with AM gave most significant inhibition on aortic wall thickness in SHRs. Plasma total antioxidant status was significantly increased by all the therapies except for the combination of high-dose DM with high-dose AM. Serum nitrite and nitrate level was significantly reduced by AM but not by DM or the combination of DM with AM. Furthermore, in vitro treatment with DM reduced angiotensin II-induced reactive oxygen species and NADPH oxidase activation in human aortic endothelial cells. Conclusions/Significance Treatment of DM reduced BP and enhanced vascular protection probably by inhibiting vascular NADPH oxidase in aged hypertensive animals with or without AM treatment. It provides the potential rationale to a novel combination treatment with low-dose DM and AM in clinical hypertension. PMID:23049937

Low-dose dextromethorphan, a NADPH oxidase inhibitor, reduces blood pressure and enhances vascular protection in experimental hypertension.

Directory of Open Access Journals (Sweden)

Tao-Cheng Wu

Full Text Available BACKGROUND: Vascular oxidative stress may be increased with age and aggravate endothelial dysfunction and vascular injury in hypertension. This study aimed to investigate the effects of dextromethorphan (DM, a NADPH oxidase inhibitor, either alone or in combination treatment, on blood pressure (BP and vascular protection in aged spontaneous hypertensive rats (SHRs. METHODOLOGY/PRINCIPAL FINDINGS: Eighteen-week-old WKY rats and SHRs were housed for 2 weeks. SHRs were randomly assigned to one of the 12 groups: untreated; DM monotherapy with 1, 5 or 25 mg/kg/day; amlodipine (AM, a calcium channel blocker monotherapy with 1 or 5 mg/kg/day; and combination therapy of DM 1, 5 or 25 mg/kg/day with AM 1 or 5 mg/kg/day individually for 4 weeks. The in vitro effects of DM were also examined. In SHRs, AM monotherapy dose-dependently reduced arterial systolic BP. DM in various doses significantly and similarly reduced arterial systolic BP. Combination of DM with AM gave additive effects on BP reduction. DM, either alone or in combination with AM, improved aortic endothelial function indicated by ex vivo acetylcholine-induced relaxation. The combination of low-dose DM with AM gave most significant inhibition on aortic wall thickness in SHRs. Plasma total antioxidant status was significantly increased by all the therapies except for the combination of high-dose DM with high-dose AM. Serum nitrite and nitrate level was significantly reduced by AM but not by DM or the combination of DM with AM. Furthermore, in vitro treatment with DM reduced angiotensin II-induced reactive oxygen species and NADPH oxidase activation in human aortic endothelial cells. CONCLUSIONS/SIGNIFICANCE: Treatment of DM reduced BP and enhanced vascular protection probably by inhibiting vascular NADPH oxidase in aged hypertensive animals with or without AM treatment. It provides the potential rationale to a novel combination treatment with low-dose DM and AM in clinical hypertension.

Iterative reconstruction technique with reduced volume CT dose index: diagnostic accuracy in pediatric acute appendicitis

Energy Technology Data Exchange (ETDEWEB)

Didier, Ryne A. [Oregon Health and Science University, Department of Diagnostic Radiology, DC7R, Portland, OR (United States); Vajtai, Petra L. [Oregon Health and Science University, Department of Pediatrics, Portland, OR (United States); Oregon Health and Science University, Department of Diagnostic Radiology, DC7R, Portland, OR (United States); Hopkins, Katharine L. [Oregon Health and Science University, Department of Diagnostic Radiology, DC7R, Portland, OR (United States); Oregon Health and Science University, Department of Pediatrics, Portland, OR (United States)

2014-07-05

Iterative reconstruction technique has been proposed as a means of reducing patient radiation dose in pediatric CT. Yet, the effect of such reductions on diagnostic accuracy has not been thoroughly evaluated. This study compares accuracy of diagnosing pediatric acute appendicitis using contrast-enhanced abdominopelvic CT scans performed with traditional pediatric weight-based protocols and filtered back projection reconstruction vs. a filtered back projection/iterative reconstruction technique blend with reduced volume CT dose index (CTDI{sub vol}). Results of pediatric contrast-enhanced abdominopelvic CT scans done for pain and/or suspected appendicitis were reviewed in two groups: A, 192 scans performed with the hospital's established weight-based CT protocols and filtered back projection reconstruction; B, 194 scans performed with iterative reconstruction technique and reduced CTDI{sub vol}. Reduced CTDI{sub vol} was achieved primarily by reductions in effective tube current-time product (mAs{sub eff}) and tube peak kilovoltage (kVp). CT interpretation was correlated with clinical follow-up and/or surgical pathology. CTDI{sub vol}, size-specific dose estimates (SSDE) and performance characteristics of the two CT techniques were then compared. Between groups A and B, mean CTDI{sub vol} was reduced by 45%, and mean SSDE was reduced by 46%. Sensitivity, specificity and diagnostic accuracy were 96%, 97% and 96% in group A vs. 100%, 99% and 99% in group B. Accuracy in diagnosing pediatric acute appendicitis was maintained in contrast-enhanced abdominopelvic CT scans that incorporated iterative reconstruction technique, despite reductions in mean CTDI{sub vol} and SSDE by nearly half as compared to the hospital's traditional weight-based protocols. (orig.)

Impact of intravenous infusion time on AAV8 vector pharmacokinetics, safety, and liver transduction in cynomolgus macaques

Directory of Open Access Journals (Sweden)

Jenny A Greig

2016-01-01

Full Text Available Systemically delivered adeno-associated viral (AAV vectors are now in early-phase clinical trials for a variety of diseases. While there is a general consensus on inclusion and exclusion criteria for each of these trials, the conditions under which vectors are infused vary significantly. In this study, we evaluated the impact of intravenous infusion rate of AAV8 vector in cynomolgus macaques on transgene expression, vector clearance from the circulation, and potential activation of the innate immune system. The dose of AAV8 vector in terms of genome copies per kilogram body weight and its concentration were fixed, while the rate of infusion varied to deliver the entire dose over different time periods, including 1, 10, or 90 minutes. Analyses during the in-life phase of the experiment included sequential evaluation of whole blood for vector genomes and appearance of proinflammatory cytokines. Liver tissues were analyzed at the time of necropsy for enhanced green fluorescent protein (eGFP expression and vector genomes. The data were remarkable with a relative absence of any statistically significant effect of infusion time on vector transduction, safety, and clearance. However, some interesting and unexpected trends did emerge.

Transcriptional Silencing of Retroviral Vectors

DEFF Research Database (Denmark)

Lund, Anders Henrik; Duch, M.; Pedersen, F.S.

1996-01-01

. Extinction of long-term vector expression has been observed after implantation of transduced hematopoietic cells as well as fibroblasts, myoblasts and hepatocytes. Here we review the influence of vector structure, integration site and cell type on transcriptional silencing. While down-regulation of proviral...... transcription is known from a number of cellular and animal models, major insight has been gained from studies in the germ line and embryonal cells of the mouse. Key elements for the transfer and expression of retroviral vectors, such as the viral transcriptional enhancer and the binding site for the t......RNA primer for reverse transcription may have a major influence on transcriptional silencing. Alterations of these elements of the vector backbone as well as the use of internal promoter elements from housekeeping genes may contribute to reduce transcriptional silencing. The use of cell culture and animal...

Efficacy of a radiation absorbing shield in reducing dose to the interventionalist during peripheral endovascular procedures: a single centre pilot study.

Science.gov (United States)

Power, S; Mirza, M; Thakorlal, A; Ganai, B; Gavagan, L D; Given, M F; Lee, M J

2015-06-01

This prospective pilot study was undertaken to evaluate the feasibility and effectiveness of using a radiation absorbing shield to reduce operator dose from scatter during lower limb endovascular procedures. A commercially available bismuth shield system (RADPAD) was used. Sixty consecutive patients undergoing lower limb angioplasty were included. Thirty procedures were performed without the RADPAD (control group) and thirty with the RADPAD (study group). Two separate methods were used to measure dose to a single operator. Thermoluminescent dosimeter (TLD) badges were used to measure hand, eye, and unshielded body dose. A direct dosimeter with digital readout was also used to measure eye and unshielded body dose. To allow for variation between control and study groups, dose per unit time was calculated. TLD results demonstrated a significant reduction in median body dose per unit time for the study group compared with controls (p = 0.001), corresponding to a mean dose reduction rate of 65 %. Median eye and hand dose per unit time were also reduced in the study group compared with control group, however, this was not statistically significant (p = 0.081 for eye, p = 0.628 for hand). Direct dosimeter readings also showed statistically significant reduction in median unshielded body dose rate for the study group compared with controls (p = 0.037). Eye dose rate was reduced for the study group but this was not statistically significant (p = 0.142). Initial results are encouraging. Use of the shield resulted in a statistically significant reduction in unshielded dose to the operator's body. Measured dose to the eye and hand of operator were also reduced but did not reach statistical significance in this pilot study.

West Nile virus infection in American Robins: new insights on dose response.

Directory of Open Access Journals (Sweden)

Kaci K VanDalen

Full Text Available West Nile virus (WNV is a vector-borne pathogen that was first detected in the United States in 1999. The natural transmission cycle of WNV involves mosquito vectors and avian hosts, which vary in their competency to transmit the virus. American robins are an abundant backyard species in the United States and appear to have an important role in the amplification and dissemination of WNV. In this study we examine the response of American robins to infection with various WNV doses within the range of those administered by some natural mosquito vectors. Thirty American robins were assigned a WNV dosage treatment and needle inoculated with 10(0.95 PFU, 10(1.26 PFU, 10(2.15 PFU, or 10(3.15 PFU. Serum samples were tested for the presence of infectious WNV and/or antibodies, while oral swabs were tested for the presence of WNV RNA. Five of the 30 (17% robins had neutralizing antibodies to WNV prior to the experiment and none developed viremia or shed WNV RNA. The proportion of WNV-seronegative birds that became viremic after WNV inoculation increased in a dose dependent manner. At the lowest dose, only 40% (2/5 of the inoculated birds developed productive infections while at the highest dose, 100% (7/7 of the birds became viremic. Oral shedding of WNV RNA followed a similar trend where robins inoculated with the lower two doses were less likely to shed viral RNA (25% than robins inoculated with one of the higher doses (92%. Viremia titers and morbidity did not increase in a dose dependent manner; only two birds succumbed to infection and, interestingly, both were inoculated with the lowest dose of WNV. It is clear that the disease ecology of WNV is a complex interplay of hosts, vectors, and viral dose delivered.

An Update on Canine Adenovirus Type 2 and Its Vectors

Science.gov (United States)

Bru, Thierry; Salinas, Sara; Kremer, Eric J.

2010-01-01

Adenovirus vectors have significant potential for long- or short-term gene transfer. Preclinical and clinical studies using human derived adenoviruses (HAd) have demonstrated the feasibility of flexible hybrid vector designs, robust expression and induction of protective immunity. However, clinical use of HAd vectors can, under some conditions, be limited by pre-existing vector immunity. Pre-existing humoral and cellular anti-capsid immunity limits the efficacy and duration of transgene expression and is poorly circumvented by injections of larger doses and immuno-suppressing drugs. This review updates canine adenovirus serotype 2 (CAV-2, also known as CAdV-2) biology and gives an overview of the generation of early region 1 (E1)-deleted to helper-dependent (HD) CAV-2 vectors. We also summarize the essential characteristics concerning their interaction with the anti-HAd memory immune responses in humans, the preferential transduction of neurons, and its high level of retrograde axonal transport in the central and peripheral nervous system. CAV-2 vectors are particularly interesting tools to study the pathophysiology and potential treatment of neurodegenerative diseases, as anti-tumoral and anti-viral vaccines, tracer of synaptic junctions, oncolytic virus and as a platform to generate chimeric vectors. PMID:21994722

Is Vector Control Sufficient to Limit Pathogen Spread in Vineyards?

Science.gov (United States)

Daugherty, M P; O'Neill, S; Byrne, F; Zeilinger, A

2015-06-01

Vector control is widely viewed as an integral part of disease management. Yet epidemiological theory suggests that the effectiveness of control programs at limiting pathogen spread depends on a variety of intrinsic and extrinsic aspects of a pathosystem. Moreover, control programs rarely evaluate whether reductions in vector density or activity translate into reduced disease prevalence. In areas of California invaded by the glassy-winged sharpshooter (Homalodisca vitripennis Germar), Pierce's disease management relies heavily on chemical control of this vector, primarily via systemic conventional insecticides (i.e., imidacloprid). But, data are lacking that attribute reduced vector pressure and pathogen spread to sharpshooter control. We surveyed 34 vineyards over successive years to assess the epidemiological value of within-vineyard chemical control. The results showed that imidacloprid reduced vector pressure without clear nontarget effects or secondary pest outbreaks. Effects on disease prevalence were more nuanced. Treatment history over the preceding 5 yr affected disease prevalence, with significantly more diseased vines in untreated compared with regularly or intermittently treated vineyards. Yet, the change in disease prevalence between years was low, with no significant effects of insecticide treatment or vector abundance. Collectively, the results suggest that within-vineyard applications of imidacloprid can reduce pathogen spread, but with benefits that may take multiple seasons to become apparent. The relatively modest effect of vector control on disease prevalence in this system may be attributable in part to the currently low regional sharpshooter population densities stemming from area-wide control, without which the need for within-vineyard vector control would be more pronounced. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Can use of adaptive statistical iterative reconstruction reduce radiation dose in unenhanced head CT? An analysis of qualitative and quantitative image quality

International Nuclear Information System (INIS)

Østerås, Bjørn Helge; Heggen, Kristin Livelten; Pedersen, Hans Kristian; Andersen, Hilde Kjernlie; Martinsen, Anne Catrine T

2016-01-01

Iterative reconstruction can reduce image noise and thereby facilitate dose reduction. To evaluate qualitative and quantitative image quality for full dose and dose reduced head computed tomography (CT) protocols reconstructed using filtered back projection (FBP) and adaptive statistical iterative reconstruction (ASIR). Fourteen patients undergoing follow-up head CT were included. All patients underwent full dose (FD) exam and subsequent 15% dose reduced (DR) exam, reconstructed using FBP and 30% ASIR. Qualitative image quality was assessed using visual grading characteristics. Quantitative image quality was assessed using ROI measurements in cerebrospinal fluid (CSF), white matter, peripheral and central gray matter. Additionally, quantitative image quality was measured in Catphan and vendor’s water phantom. There was no significant difference in qualitative image quality between FD FBP and DR ASIR. Comparing same scan FBP versus ASIR, a noise reduction of 28.6% in CSF and between −3.7 and 3.5% in brain parenchyma was observed. Comparing FD FBP versus DR ASIR, a noise reduction of 25.7% in CSF, and −7.5 and 6.3% in brain parenchyma was observed. Image contrast increased in ASIR reconstructions. Contrast-to-noise ratio was improved in DR ASIR compared to FD FBP. In phantoms, noise reduction was in the range of 3 to 28% with image content. There was no significant difference in qualitative image quality between full dose FBP and dose reduced ASIR. CNR improved in DR ASIR compared to FD FBP mostly due to increased contrast, not reduced noise. Therefore, we recommend using caution if reducing dose and applying ASIR to maintain image quality

Efficacy of a Radiation Absorbing Shield in Reducing Dose to the Interventionalist During Peripheral Endovascular Procedures: A Single Centre Pilot Study

International Nuclear Information System (INIS)

Power, S.; Mirza, M.; Thakorlal, A.; Ganai, B.; Gavagan, L. D.; Given, M. F.; Lee, M. J.

2015-01-01

PurposeThis prospective pilot study was undertaken to evaluate the feasibility and effectiveness of using a radiation absorbing shield to reduce operator dose from scatter during lower limb endovascular procedures.Materials and MethodsA commercially available bismuth shield system (RADPAD) was used. Sixty consecutive patients undergoing lower limb angioplasty were included. Thirty procedures were performed without the RADPAD (control group) and thirty with the RADPAD (study group). Two separate methods were used to measure dose to a single operator. Thermoluminescent dosimeter (TLD) badges were used to measure hand, eye, and unshielded body dose. A direct dosimeter with digital readout was also used to measure eye and unshielded body dose. To allow for variation between control and study groups, dose per unit time was calculated.ResultsTLD results demonstrated a significant reduction in median body dose per unit time for the study group compared with controls (p = 0.001), corresponding to a mean dose reduction rate of 65 %. Median eye and hand dose per unit time were also reduced in the study group compared with control group, however, this was not statistically significant (p = 0.081 for eye, p = 0.628 for hand). Direct dosimeter readings also showed statistically significant reduction in median unshielded body dose rate for the study group compared with controls (p = 0.037). Eye dose rate was reduced for the study group but this was not statistically significant (p = 0.142).ConclusionInitial results are encouraging. Use of the shield resulted in a statistically significant reduction in unshielded dose to the operator’s body. Measured dose to the eye and hand of operator were also reduced but did not reach statistical significance in this pilot study

Efficacy of a Radiation Absorbing Shield in Reducing Dose to the Interventionalist During Peripheral Endovascular Procedures: A Single Centre Pilot Study

Energy Technology Data Exchange (ETDEWEB)

Power, S.; Mirza, M.; Thakorlal, A.; Ganai, B.; Gavagan, L. D.; Given, M. F.; Lee, M. J., E-mail: mlee@rcsi.ie [Beaumont Hospital, Imaging and Interventional Radiology Department (Ireland)

2015-06-15

PurposeThis prospective pilot study was undertaken to evaluate the feasibility and effectiveness of using a radiation absorbing shield to reduce operator dose from scatter during lower limb endovascular procedures.Materials and MethodsA commercially available bismuth shield system (RADPAD) was used. Sixty consecutive patients undergoing lower limb angioplasty were included. Thirty procedures were performed without the RADPAD (control group) and thirty with the RADPAD (study group). Two separate methods were used to measure dose to a single operator. Thermoluminescent dosimeter (TLD) badges were used to measure hand, eye, and unshielded body dose. A direct dosimeter with digital readout was also used to measure eye and unshielded body dose. To allow for variation between control and study groups, dose per unit time was calculated.ResultsTLD results demonstrated a significant reduction in median body dose per unit time for the study group compared with controls (p = 0.001), corresponding to a mean dose reduction rate of 65 %. Median eye and hand dose per unit time were also reduced in the study group compared with control group, however, this was not statistically significant (p = 0.081 for eye, p = 0.628 for hand). Direct dosimeter readings also showed statistically significant reduction in median unshielded body dose rate for the study group compared with controls (p = 0.037). Eye dose rate was reduced for the study group but this was not statistically significant (p = 0.142).ConclusionInitial results are encouraging. Use of the shield resulted in a statistically significant reduction in unshielded dose to the operator’s body. Measured dose to the eye and hand of operator were also reduced but did not reach statistical significance in this pilot study.

Low-Dose Gene Therapy for Murine PKU Using Episomal Naked DNA Vectors Expressing PAH from Its Endogenous Liver Promoter

Directory of Open Access Journals (Sweden)

Hiu Man Grisch-Chan

2017-06-01

Full Text Available Limited duration of transgene expression, insertional mutagenesis, and size limitations for transgene cassettes pose challenges and risk factors for many gene therapy vectors. Here, we report on physiological expression of liver phenylalanine hydroxylase (PAH by delivery of naked DNA/minicircle (MC-based vectors for correction of homozygous enu2 mice, a model of human phenylketonuria (PKU. Because MC vectors lack a defined size limit, we constructed a MC vector expressing a codon-optimized murine Pah cDNA that includes a truncated intron and is under the transcriptional control of a 3.6-kb native Pah promoter/enhancer sequence. This vector, delivered via hydrodynamic injection, yielded therapeutic liver PAH activity and sustained correction of blood phenylalanine comparable to viral or synthetic liver promoters. Therapeutic efficacy was seen with vector copy numbers of 95% loss of vector genomes and PAH activity in liver, demonstrating that MC vectors had not integrated into the liver genome. In conclusion, MC vectors, which do not have a defined size-limitation, offer a favorable safety profile for hepatic gene therapy due to their non-integration in combination with native promoters.

Non-Replicating Adenovirus-Vectored Anthrax Vaccine

International Nuclear Information System (INIS)

Van Kampen, K. R.; Zhang, J.; Jex, E.; Tang, D. C.

2007-01-01

As bioterrorism is emerging as a national threat, it is urgent to develop a new generation of anthrax vaccines that can be rapidly produced and mass administered in an emergency setting. We have demonstrated that protective immunity against anthrax spores could be elicited in mice by intranasal administration of a non-replicating human adenovirus serotype 5 (Ad5)-derived vector encoding Bacillus anthracis protective antigen (PA) in a single-dose regimen. The potency of an Ad5 vector encoding PA was remarkably enhanced by codon optimization of the PA gene to match the tRNA pool found in human cells. This nasal vaccine can be mass-administered by non-medical personnel during a bioterrorist attack. In addition, replication-competent adenovirus (RCA)-free Ad5-vectored anthrax vaccines can be mass produced in PER.C6 cells in serum-free wave bioreactors and purified by column chromatography to meet a surge in demand. The non-replicating nature of this new generation of anthrax vaccine ensures an excellent safety profile for vaccines and the environment.(author)

Low-Dose Aspirin Reduces Breast Cancer Risk in Women with Diabetes: A Nationwide Retrospective Cohort Study in Taiwan.

Science.gov (United States)

Yang, Yi-Sun; Kornelius, Edy; Chiou, Jeng-Yuan; Lai, Yung-Rung; Lo, Shih-Chang; Peng, Chiung-Huei; Huang, Chien-Ning

2017-12-01

Low-dose aspirin is commonly used for preventing cardiovascular disease in people with diabetes, but its association with cancer remains controversial. This study used a nationwide population-based reimbursement database to investigate the relationship between low-dose aspirin use and breast cancer incidence in women with diabetes. This retrospective cohort study was conducted using data retrieved from the National Health Insurance Research Database in Taiwan from January 1, 1998 to December 31, 2011. Women diagnosed as having diabetes with low-dose aspirin use (75-165 mg daily) were identified as the study population, whereas those without low-dose aspirin use were selected as the comparison group. We analyzed 148,739 patients with diabetes. Their mean age (standard deviation) was 63.3 (12.8) years. A total of 27,378 patients were taking aspirin. Overall, the use of aspirin in patients with diabetes reduced the risk of breast cancer by 18% (hazard ratio [HR], 0.82; 95% confidence interval [CI], 0.71-0.94) after adjustment for potential confounders, namely age and comorbidities. Specifically, a cumulative dose of aspirin exceeding 88,900 mg was observed to reduce the risk of breast cancer by 47% (HR, 0.53, 95% CI, 0.43-0.67); however, low (aspirin did not reduce the risk of breast cancer. Our findings suggest that a cumulative aspirin dosage of more than 88,900 mg daily was associated with a reduced risk of breast cancer in women with diabetes. However, additional studies are necessary to confirm these findings.

Effects of Vector Backbone and Pseudotype on Lentiviral Vector-mediated Gene Transfer: Studies in Infant ADA-Deficient Mice and Rhesus Monkeys

Science.gov (United States)

Carbonaro Sarracino, Denise; Tarantal, Alice F; Lee, C Chang I.; Martinez, Michele; Jin, Xiangyang; Wang, Xiaoyan; Hardee, Cinnamon L; Geiger, Sabine; Kahl, Christoph A; Kohn, Donald B

2014-01-01

Systemic delivery of a lentiviral vector carrying a therapeutic gene represents a new treatment for monogenic disease. Previously, we have shown that transfer of the adenosine deaminase (ADA) cDNA in vivo rescues the lethal phenotype and reconstitutes immune function in ADA-deficient mice. In order to translate this approach to ADA-deficient severe combined immune deficiency patients, neonatal ADA-deficient mice and newborn rhesus monkeys were treated with species-matched and mismatched vectors and pseudotypes. We compared gene delivery by the HIV-1-based vector to murine γ-retroviral vectors pseudotyped with vesicular stomatitis virus-glycoprotein or murine retroviral envelopes in ADA-deficient mice. The vesicular stomatitis virus-glycoprotein pseudotyped lentiviral vectors had the highest titer and resulted in the highest vector copy number in multiple tissues, particularly liver and lung. In monkeys, HIV-1 or simian immunodeficiency virus vectors resulted in similar biodistribution in most tissues including bone marrow, spleen, liver, and lung. Simian immunodeficiency virus pseudotyped with the gibbon ape leukemia virus envelope produced 10- to 30-fold lower titers than the vesicular stomatitis virus-glycoprotein pseudotype, but had a similar tissue biodistribution and similar copy number in blood cells. The relative copy numbers achieved in mice and monkeys were similar when adjusted to the administered dose per kg. These results suggest that this approach can be scaled-up to clinical levels for treatment of ADA-deficient severe combined immune deficiency subjects with suboptimal hematopoietic stem cell transplantation options. PMID:24925206

Effects of vector backbone and pseudotype on lentiviral vector-mediated gene transfer: studies in infant ADA-deficient mice and rhesus monkeys.

Science.gov (United States)

Carbonaro Sarracino, Denise; Tarantal, Alice F; Lee, C Chang I; Martinez, Michele; Jin, Xiangyang; Wang, Xiaoyan; Hardee, Cinnamon L; Geiger, Sabine; Kahl, Christoph A; Kohn, Donald B

2014-10-01

Systemic delivery of a lentiviral vector carrying a therapeutic gene represents a new treatment for monogenic disease. Previously, we have shown that transfer of the adenosine deaminase (ADA) cDNA in vivo rescues the lethal phenotype and reconstitutes immune function in ADA-deficient mice. In order to translate this approach to ADA-deficient severe combined immune deficiency patients, neonatal ADA-deficient mice and newborn rhesus monkeys were treated with species-matched and mismatched vectors and pseudotypes. We compared gene delivery by the HIV-1-based vector to murine γ-retroviral vectors pseudotyped with vesicular stomatitis virus-glycoprotein or murine retroviral envelopes in ADA-deficient mice. The vesicular stomatitis virus-glycoprotein pseudotyped lentiviral vectors had the highest titer and resulted in the highest vector copy number in multiple tissues, particularly liver and lung. In monkeys, HIV-1 or simian immunodeficiency virus vectors resulted in similar biodistribution in most tissues including bone marrow, spleen, liver, and lung. Simian immunodeficiency virus pseudotyped with the gibbon ape leukemia virus envelope produced 10- to 30-fold lower titers than the vesicular stomatitis virus-glycoprotein pseudotype, but had a similar tissue biodistribution and similar copy number in blood cells. The relative copy numbers achieved in mice and monkeys were similar when adjusted to the administered dose per kg. These results suggest that this approach can be scaled-up to clinical levels for treatment of ADA-deficient severe combined immune deficiency subjects with suboptimal hematopoietic stem cell transplantation options.

Adeno-associated viral vector transduction of human mesenchymal stem cells

DEFF Research Database (Denmark)

Stender, Stefan; Murphy, Mary; O'Brien, Tim

2007-01-01

Mesenchymal stem cells (MSCs) have received considerable attention in the emerging field of regenerative medicine. One aspect of MSC research focuses on genetically modifying the cells with the aim of enhancing their regenerative potential. Adeno-associated virus (AAV) holds promise as a vector...... in human MSCs and to assess whether AAV transduction affects MSC multipotentiality. The results indicated that human MSCs could indeed be transiently transduced in vitro by the AAV2 vector with efficiencies of up to 65%. The percentage of GFP-positive cells peaked at 4 days post-transduction and declined...... rapidly towards 0% after day 8. The level of transgene expression in the GFP-positive population increased 4-fold over a 10,000 fold viral dose increase. This dose-response contrasted with the 200-fold increase observed in similarly transduced 293-cells, indicating a relatively restricted transgene...

Matrix elements of a hyperbolic vector operator under SO(2,1)

International Nuclear Information System (INIS)

Zettili, N.; Boukahil, A.

2003-01-01

We deal here with the use of Wigner–Eckart type arguments to calculate the matrix elements of a hyperbolic vector operator V-vector by expressing them in terms of reduced matrix elements. In particular, we focus on calculating the matrix elements of this vector operator within the basis of the hyperbolic angular momentum T-vector whose components T-vector 1 , T-vector 2 , T-vector 3 satisfy an SO(2,1) Lie algebra. We show that the commutation rules between the components of V-vector and T-vector can be inferred from the algebra of ordinary angular momentum. We then show that, by analogy to the Wigner–Eckart theorem, we can calculate the matrix elements of V-vector within a representation where T-vector 2 and T-vector 3 are jointly diagonal. (author)

Nonlinear image blending for dual-energy MDCT of the abdomen: can image quality be preserved if the contrast medium dose is reduced?

Science.gov (United States)

Mileto, Achille; Ramirez-Giraldo, Juan Carlos; Marin, Daniele; Alfaro-Cordoba, Marcela; Eusemann, Christian D; Scribano, Emanuele; Blandino, Alfredo; Mazziotti, Silvio; Ascenti, Giorgio

2014-10-01

The objective of this study was to compare the image quality of a dual-energy nonlinear image blending technique at reduced load of contrast medium with a simulated 120-kVp linear blending technique at a full dose during portal venous phase MDCT of the abdomen. Forty-five patients (25 men, 20 women; mean age, 65.6 ± 9.7 [SD] years; mean body weight, 74.9 ± 12.4 kg) underwent contrast-enhanced single-phase dual-energy CT of the abdomen by a random assignment to one of three different contrast medium (iomeprol 400) dose injection protocols: 1.3, 1.0, or 0.65 mL/kg of body weight. The contrast-to-noise ratio (CNR) and noise at the portal vein, liver, aorta, and kidney were compared among the different datasets using the ANOVA. Three readers qualitatively assessed all datasets in a blinded and independent fashion. Nonlinear blended images at a 25% reduced dose allowed a significant improvement in CNR (p < 0.05 for all comparisons), compared with simulated 120-kVp linear blended images at a full dose. No statistically significant difference existed in CNR and noise between the nonlinear blended images at a 50% reduced dose and the simulated 120-kVp linear blended images at a full dose. Nonlinear blended images at a 50% reduced dose were considered in all cases to have acceptable image quality. The dual-energy nonlinear image blending technique allows reducing the dose of contrast medium up to 50% during portal venous phase imaging of the abdomen while preserving image quality.

Simple shielding reduces dose to the contralateral breast during prone breast cancer radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Goyal, Uma, E-mail: uma.goyal@gmail.com; Locke, Angela; Smith-Raymond, Lexie; Georgiev, Georgi N.

2016-07-01

shielded dose means were 12.68 and 1.54 cGy, respectively. When comparing medial and lateral portions of the contralateral bolus-based doses without and with Pb, the shield significantly reduced dose to both sides of the contralateral breast (medial p = 2.64 × 10{sup −14}, lateral p = 4.91 × 10{sup −6}). The prone 0.2-cm Pb shield significantly reduced scatter dose to the contralateral breast on the order of 2 to 3 times. Reductions may be clinically relevant for women younger than 45 years by decreasing the risk of contralateral radiation-induced breast cancer in patients receiving radiation therapy for breast cancer. This shield is simple as it would be a part of the prone breast board during treatments, but future studies are warranted for safety and efficacy clinically.

Measures taken by the supervisory authority to reduce extremity doses in nuclear medicine facilities in Switzerland

International Nuclear Information System (INIS)

Stritt, Nicolas; Linder, Reto

2011-01-01

In its capacity as the supervisory authority, the Swiss Federal Office of Public Health (SFOPH) has responded to the increase in extremity doses observed in nuclear medicine facilities in Switzerland over the past decade by introducing facility-specific radiation protection audits. These audits have raised the awareness of the staff members concerned with the problem of high extremity doses which arise from handling beta emitters and PET nuclides and prevented any further rise in the extremity doses. However, the evaluation of these audits has also shown that there is still considerable scope for improvement in terms of reducing extremity doses and that further measures are therefore required. Facility-specific and person-specific investigations are currently being conducted with the support of the SFOPH. Their aim is to show facilities which operations during the preparation and application of diagnostic and therapeutic radiopharmaceuticals lead to high extremity doses. This will enable the reduction of extremity doses for nuclear medicine staff as well as ensure that the dose limits are adhered to, in spite of the increasing numbers of examinations.

A programme to reduce down-time and site radiation dose through improvements in control rod design

International Nuclear Information System (INIS)

Izatt, J.A.; Scobie, J.

1985-01-01

On the UTR-300 reactor at SURRC, it has been found necessary to carry out preventive or remedial maintenance at least once per year on the in-core elements of the control rod assemblies. This has led to reduced availability of the reactor and to significant overall radiation doses to the few long-serving staff members who carry out this work. In an attempt to reduce down-time and radiation dose to staff a radical re-design of the control assemblies was undertaken in-house, and a conversion programme has been underway over the last four years. Details of the design improvements are presented together with a discussion of the operating experience to date. (author)

Intensity-Modulated Radiotherapy of Head and Neck Cancer Aiming to Reduce Dysphagia: Early Dose-Effect Relationships for the Swallowing Structures

International Nuclear Information System (INIS)

Feng, Felix Y.; Kim, Hyungjin M.; Lyden, Teresa H.; Haxer, Marc J.; Feng, Mary; Worden, Frank P.; Chepeha, Douglas B.; Eisbruch, Avraham

2007-01-01

Purpose: To present initial results of a clinical trial of intensity-modulated radiotherapy (IMRT) aiming to spare the swallowing structures whose dysfunction after chemoradiation is a likely cause of dysphagia and aspiration, without compromising target doses. Methods and Materials: This was a prospective, longitudinal study of 36 patients with Stage III-IV oropharyngeal (31) or nasopharyngeal (5) cancer. Definitive chemo-IMRT spared salivary glands and swallowing structures: pharyngeal constrictors (PC), glottic and supraglottic larynx (GSL), and esophagus. Lateral but not medial retropharyngeal nodes were considered at risk. Dysphagia endpoints included objective swallowing dysfunction (videofluoroscopy), and both patient-reported and observer-rated scores. Correlations between doses and changes in these endpoints from pre-therapy to 3 months after therapy were assessed. Results: Significant correlations were observed between videofluoroscopy-based aspirations and the mean doses to the PC and GSL, as well as the partial volumes of these structures receiving 50-65 Gy; the highest correlations were associated with doses to the superior PC (p = 0.005). All patients with aspirations received mean PC doses >60 Gy or PC V 65 >50%, and GSL V 50 >50%. Reduced laryngeal elevation and epiglottic inversion were correlated with mean PC and GSL doses (p 70 >50%. Worsening patient-reported liquid swallowing was correlated with mean PC (p = 0.05) and esophageal (p 0.02) doses. Only mean PC doses were correlated with worsening patient-reported solid swallowing (p = 0.04) and observer-rated swallowing scores (p = 0.04). Conclusions: These dose-volume-effect relationships provide initial IMRT optimization goals and motivate further efforts to reduce swallowing structures doses to reduce dysphagia and aspiration

Sub-milliSievert (sub-mSv) CT colonography: a prospective comparison of image quality and polyp conspicuity at reduced-dose versus standard-dose imaging

Energy Technology Data Exchange (ETDEWEB)

Lubner, Meghan G.; Pooler, B.D.; Kitchin, Douglas R.; Kim, David H.; Munoz del Rio, Alejandro; Pickhardt, Perry J. [University of Wisconsin School of Medicine and Public Health, E3/311 Clinical Sciences Center, Departments of Radiology, Madison, WI (United States); Tang, Jie [University of Wisconsin School of Medicine and Public Health, Medical Physics, Madison, WI (United States); Li, Ke; Chen, Guang-Hong [University of Wisconsin School of Medicine and Public Health, E3/311 Clinical Sciences Center, Departments of Radiology, Madison, WI (United States); University of Wisconsin School of Medicine and Public Health, Medical Physics, Madison, WI (United States)

2015-07-15

To prospectively compare reduced-dose (RD) CT colonography (CTC) with standard-dose (SD) imaging using several reconstruction algorithms. Following SD supine CTC, 40 patients (mean age, 57.3 years; 17 M/23 F; mean BMI, 27.2) underwent an additional RD supine examination (targeted dose reduction, 70-90 %). DLP, CTDI{sub vol}, effective dose, and SSDE were compared. Several reconstruction algorithms were applied to RD series. SD-FBP served as reference standard. Objective image noise, subjective image quality and polyp conspicuity were assessed. Mean CTDI{sub vol} and effective dose for RD series was 0.89 mGy (median 0.65) and 0.6 mSv (median 0.44), compared with 3.8 mGy (median 3.1) and 2.8 mSv (median 2.3) for SD series, respectively. Mean dose reduction was 78 %. Mean image noise was significantly reduced on RD-PICCS (24.3 ± 19HU) and RD-MBIR (19 ± 18HU) compared with RD-FBP (90 ± 33), RD-ASIR (72 ± 27) and SD-FBP (47 ± 14 HU). 2D image quality score was higher with RD-PICCS, RD-MBIR, and SD-FBP (2.7 ± 0.4/2.8 ± 0.4/2.9 ± 0.6) compared with RD-FBP (1.5 ± 0.4) and RD-ASIR (1.8 ± 0.44). A similar trend was seen with 3D image quality scores. Polyp conspicuity scores were similar between SD-FBP/RD-PICCS/RD-MBIR (3.5 ± 0.6/3.2 ± 0.8/3.3 ± 0.6). Sub-milliSievert CTC performed with iterative reconstruction techniques demonstrate decreased image quality compared to SD, but improved image quality compared to RD images reconstructed with FBP. (orig.)

Dexmedetomidine reduces pain associated with rocuronium injection without causing a decrease in BIS values: a dose-response study.

Science.gov (United States)

Joo, Jin; Baek, Jungwon; Lee, Jaemin

2014-09-01

To examine whether dexmedetomidine reduces the injection pain of propofol and rocuronium and to investigate whether the decrease in injection pain is associated with the known sedative action of dexmedetomidine. Randomized, double-blind, placebo-controlled clinical comparison study. Patients undergoing general anesthesia with intubation received 40 mg of 1% lidocaine (lidocaine group; n = 28), 0.25 μg/kg of dexmedetomidine (low-dose group; n = 27), 0.5 μg/kg of dexmedetomidine (subclinical dose group; n = 28), 1.0 μg/kg of dexmedetomidine (clinical dose group, n = 27), or normal saline (saline group; n = 28) before anesthetic induction. Pain associated with propofol and rocuronium injection was assessed using a 10-point verbal analog scale (VAS) and a 4-point withdrawal movement scale, respectively. The BIS value was measured 60 seconds after administration of the study drug, and at the time of rocuronium injection and intubation. The overall incidence of withdrawal movements due to rocuronium decreased significantly as the dose of dexmedetomidine increased (92.8%, 85.2%, 78.6%, and 51.9% in the saline, low-dose, subclinical dose, and clinical dose groups, respectively; P = 0.001). There was no significant difference in BIS values among the groups 60 seconds after study drug administration or at the time of rocuronium injection. Dexmedetomidine reduced pain associated with rocuronium injection in a dose-dependent manner. This effect was not associated with the decrease in BIS value. Copyright © 2014 Elsevier Inc. All rights reserved.

Model-based iterative reconstruction and adaptive statistical iterative reconstruction: dose-reduced CT for detecting pancreatic calcification

International Nuclear Information System (INIS)

Yasaka, Koichiro; Katsura, Masaki; Akahane, Masaaki; Sato, Jiro; Matsuda, Izuru; Ohtomo, Kuni

2016-01-01

Iterative reconstruction methods have attracted attention for reducing radiation doses in computed tomography (CT). To investigate the detectability of pancreatic calcification using dose-reduced CT reconstructed with model-based iterative construction (MBIR) and adaptive statistical iterative reconstruction (ASIR). This prospective study approved by Institutional Review Board included 85 patients (57 men, 28 women; mean age, 69.9 years; mean body weight, 61.2 kg). Unenhanced CT was performed three times with different radiation doses (reference-dose CT [RDCT], low-dose CT [LDCT], ultralow-dose CT [ULDCT]). From RDCT, LDCT, and ULDCT, images were reconstructed with filtered-back projection (R-FBP, used for establishing reference standard), ASIR (L-ASIR), and MBIR and ASIR (UL-MBIR and UL-ASIR), respectively. A lesion (pancreatic calcification) detection test was performed by two blinded radiologists with a five-point certainty level scale. Dose-length products of RDCT, LDCT, and ULDCT were 410, 97, and 36 mGy-cm, respectively. Nine patients had pancreatic calcification. The sensitivity for detecting pancreatic calcification with UL-MBIR was high (0.67–0.89) compared to L-ASIR or UL-ASIR (0.11–0.44), and a significant difference was seen between UL-MBIR and UL-ASIR for one reader (P = 0.014). The area under the receiver-operating characteristic curve for UL-MBIR (0.818–0.860) was comparable to that for L-ASIR (0.696–0.844). The specificity was lower with UL-MBIR (0.79–0.92) than with L-ASIR or UL-ASIR (0.96–0.99), and a significant difference was seen for one reader (P < 0.01). In UL-MBIR, pancreatic calcification can be detected with high sensitivity, however, we should pay attention to the slightly lower specificity

Model-based iterative reconstruction and adaptive statistical iterative reconstruction: dose-reduced CT for detecting pancreatic calcification.

Science.gov (United States)

Yasaka, Koichiro; Katsura, Masaki; Akahane, Masaaki; Sato, Jiro; Matsuda, Izuru; Ohtomo, Kuni

2016-01-01

Iterative reconstruction methods have attracted attention for reducing radiation doses in computed tomography (CT). To investigate the detectability of pancreatic calcification using dose-reduced CT reconstructed with model-based iterative construction (MBIR) and adaptive statistical iterative reconstruction (ASIR). This prospective study approved by Institutional Review Board included 85 patients (57 men, 28 women; mean age, 69.9 years; mean body weight, 61.2 kg). Unenhanced CT was performed three times with different radiation doses (reference-dose CT [RDCT], low-dose CT [LDCT], ultralow-dose CT [ULDCT]). From RDCT, LDCT, and ULDCT, images were reconstructed with filtered-back projection (R-FBP, used for establishing reference standard), ASIR (L-ASIR), and MBIR and ASIR (UL-MBIR and UL-ASIR), respectively. A lesion (pancreatic calcification) detection test was performed by two blinded radiologists with a five-point certainty level scale. Dose-length products of RDCT, LDCT, and ULDCT were 410, 97, and 36 mGy-cm, respectively. Nine patients had pancreatic calcification. The sensitivity for detecting pancreatic calcification with UL-MBIR was high (0.67-0.89) compared to L-ASIR or UL-ASIR (0.11-0.44), and a significant difference was seen between UL-MBIR and UL-ASIR for one reader (P = 0.014). The area under the receiver-operating characteristic curve for UL-MBIR (0.818-0.860) was comparable to that for L-ASIR (0.696-0.844). The specificity was lower with UL-MBIR (0.79-0.92) than with L-ASIR or UL-ASIR (0.96-0.99), and a significant difference was seen for one reader (P < 0.01). In UL-MBIR, pancreatic calcification can be detected with high sensitivity, however, we should pay attention to the slightly lower specificity.

Adulticidal Susceptibility Evaluation of Aedes albopictus Using New Diagnostic Doses in Penang Island, Malaysia.

Science.gov (United States)

Rahim, Junaid; Ahmad, Abu H; Ahmad, Hamdan; Ishak, Intan H; Rus, Adanan Che; Maimusa, Hamisu A

2017-09-01

Insecticide-based vector control approaches are facing challenges due to the development of resistance in vector mosquitoes. Therefore, a proper resistance surveillance program using baseline lethal concentrations is crucial for resistance management strategies. Currently, the World Health Organization's (WHO) diagnostic doses established for Aedes aegypti and Anopheles species are being used to study the resistance status of Aedes albopictus. In this study, we established the diagnostic doses for permethrin, deltamethrin, and malathion using a known susceptible reference strain. Five field-collected populations were screened against these doses, following the WHO protocol. This study established the diagnostic dose of malathion at 2.4%, permethrin at 0.95%, and deltamethrin at 0.28%, which differ from the WHO doses for Aedes aegypti and Anopheles spp. Among the insecticides tested on the 5 wild populations, only deltamethrin showed high effectiveness. Different susceptibility and resistance patterns were observed with permethrin, malathion, and dichloro-diphenyl-trichloroethane (DDT) at 4%. This study may assist the health authorities to improve future chemical-based vector control operations in dengue-endemic areas.

Automatic spectral imaging protocol selection and iterative reconstruction in abdominal CT with reduced contrast agent dose: initial experience

Energy Technology Data Exchange (ETDEWEB)

Lv, Peijie; Liu, Jie; Chai, Yaru; Yan, Xiaopeng; Gao, Jianbo; Dong, Junqiang [The First Affiliated Hospital of Zhengzhou University, Department of Radiology, Zhengzhou, Henan Province (China)

2017-01-15

To evaluate the feasibility, image quality, and radiation dose of automatic spectral imaging protocol selection (ASIS) and adaptive statistical iterative reconstruction (ASIR) with reduced contrast agent dose in abdominal multiphase CT. One hundred and sixty patients were randomly divided into two scan protocols (n = 80) each; protocol A, 120 kVp/450 mgI/kg, filtered back projection algorithm (FBP); protocol B, spectral CT imaging with ASIS and 40 to 70 keV monochromatic images generated per 300 mgI/kg, ASIR algorithm. Quantitative parameters (image noise and contrast-to-noise ratios [CNRs]) and qualitative visual parameters (image noise, small structures, organ enhancement, and overall image quality) were compared. Monochromatic images at 50 keV and 60 keV provided similar or lower image noise, but higher contrast and overall image quality as compared with 120-kVp images. Despite the higher image noise, 40-keV images showed similar overall image quality compared to 120-kVp images. Radiation dose did not differ between the two protocols, while contrast agent dose in protocol B was reduced by 33 %. Application of ASIR and ASIS to monochromatic imaging from 40 to 60 keV allowed contrast agent dose reduction with adequate image quality and without increasing radiation dose compared to 120 kVp with FBP. (orig.)

Automatic spectral imaging protocol selection and iterative reconstruction in abdominal CT with reduced contrast agent dose: initial experience

International Nuclear Information System (INIS)

Lv, Peijie; Liu, Jie; Chai, Yaru; Yan, Xiaopeng; Gao, Jianbo; Dong, Junqiang

2017-01-01

To evaluate the feasibility, image quality, and radiation dose of automatic spectral imaging protocol selection (ASIS) and adaptive statistical iterative reconstruction (ASIR) with reduced contrast agent dose in abdominal multiphase CT. One hundred and sixty patients were randomly divided into two scan protocols (n = 80) each; protocol A, 120 kVp/450 mgI/kg, filtered back projection algorithm (FBP); protocol B, spectral CT imaging with ASIS and 40 to 70 keV monochromatic images generated per 300 mgI/kg, ASIR algorithm. Quantitative parameters (image noise and contrast-to-noise ratios [CNRs]) and qualitative visual parameters (image noise, small structures, organ enhancement, and overall image quality) were compared. Monochromatic images at 50 keV and 60 keV provided similar or lower image noise, but higher contrast and overall image quality as compared with 120-kVp images. Despite the higher image noise, 40-keV images showed similar overall image quality compared to 120-kVp images. Radiation dose did not differ between the two protocols, while contrast agent dose in protocol B was reduced by 33 %. Application of ASIR and ASIS to monochromatic imaging from 40 to 60 keV allowed contrast agent dose reduction with adequate image quality and without increasing radiation dose compared to 120 kVp with FBP. (orig.)

Automatic exposure control to reduce the dose in subsecond multislice spiral CT: phantom measurements and clinical results

International Nuclear Information System (INIS)

Greess, H.; Bautz, W.; Baum, U.; Wolf, H.; Suess, C.; Kalender, W.A.

2004-01-01

Purpose: To investigate the potential of dose reduction in multislice spiral CT (MSCT) with automatic exposure control. Materials and Methods: The study was performed on a Sensation 4 multislice scanner. This prototype implementation analyzed the distribution of the attenuation along the z-axis in the lateral and sagittal directions of the digital radiogram. Depending on this distribution of the attenuation, the tube current (mA) is defined for every tube rotation. In addition, the tube current was modulated during each tube rotation. First, a three step oval water phantom was measured to evaluate the potential of this method with respect to dose reduction and image quality. In a patient study (n=26), four different scan regions (shoulder, thorax, abdomen, pelvis) were examined and dose (mAs) and image quality evaluated in comparison to examinations with a standard protocol for these regions in adults and a weight-adjusted standard protocol in children. The image quality was classified in consensus as good, sufficient and poor image quality. Results: By adapting and modulating the tube current, we substantially reduced the variation of noise in one spiral scan and in one scan region of our patient collective. The dose (average mAs) was reduced by 31% to 66% in children (mean 44%) and between 35% and 64% in adults (mean 53%), depending on the scan region. The image quality was substantially improved in regions with high attenuation and did not suffer in low attenuation regions. Conclusion: The dose can be reduced substantially by an automatic exposure control including angular tube current modulation with the same or improved image quality. (orig.) [de

Evaluation of the Effects of Integrated Management Weed Control on Corn Field by Using Reduced Dose of Foramsulfuron and Nicosulfuron Herbicides

Directory of Open Access Journals (Sweden)

M. Matinfar

2011-09-01

Full Text Available In order to evaluate the effects of integrated weed management on weed control by using reduced herbicide dose, a field experiment was conducted in 2010 in Qazvin. The experiment was conducted in randomized complete block design with 24 treatments and 4 replications. The treatments were: different planting patterns at three levels (single row, square double rows and zigzag double row  plantings and doses of  Nicosulfuron and Foramsulfuron application at four levels (1, 1/5, 2 and 2/5 liters per hectare, The results showed that among the different planting patterns, zigzag planting reduced weed populations and their dry weights significantly. Foramsulfuron herbicide could control weeds better than Nicosulfuron. Among the herbicide dosages, 2/5 litter dose per hectare highly reduced weed density its dry weight as compared to one litter dose.

New image-processing and noise-reduction software reduces radiation dose during complex endovascular procedures.

Science.gov (United States)

Kirkwood, Melissa L; Guild, Jeffrey B; Arbique, Gary M; Tsai, Shirling; Modrall, J Gregory; Anderson, Jon A; Rectenwald, John; Timaran, Carlos

2016-11-01

procedures with and without Clarity were not significantly different. For all cases, procedure radiation dose to the patient and the primary and assistant operators were significantly decreased in the Clarity group by 60% compared with the non-Clarity group. By procedure type, fluorography dose rates decreased from 44% for fenestrated endovascular repair and up to 70% with lower extremity interventions. Fluoroscopy dose rates also significantly decreased, from about 37% to 47%, depending on procedure type. The AlluraClarity system reduces the patient and primary operator's radiation dose by more than half during CEPs. This feature appears to be an effective tool in lowering the radiation dose while maintaining image quality. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Automated beam placement for breast radiotherapy using a support vector machine based algorithm

International Nuclear Information System (INIS)

Zhao Xuan; Kong, Dewen; Jozsef, Gabor; Chang, Jenghwa; Wong, Edward K.; Formenti, Silvia C.; Wang Yao

2012-01-01

Purpose: To develop an automated beam placement technique for whole breast radiotherapy using tangential beams. We seek to find optimal parameters for tangential beams to cover the whole ipsilateral breast (WB) and minimize the dose to the organs at risk (OARs). Methods: A support vector machine (SVM) based method is proposed to determine the optimal posterior plane of the tangential beams. Relative significances of including/avoiding the volumes of interests are incorporated into the cost function of the SVM. After finding the optimal 3-D plane that separates the whole breast (WB) and the included clinical target volumes (CTVs) from the OARs, the gantry angle, collimator angle, and posterior jaw size of the tangential beams are derived from the separating plane equation. Dosimetric measures of the treatment plans determined by the automated method are compared with those obtained by applying manual beam placement by the physicians. The method can be further extended to use multileaf collimator (MLC) blocking by optimizing posterior MLC positions. Results: The plans for 36 patients (23 prone- and 13 supine-treated) with left breast cancer were analyzed. Our algorithm reduced the volume of the heart that receives >500 cGy dose (V5) from 2.7 to 1.7 cm 3 (p = 0.058) on average and the volume of the ipsilateral lung that receives >1000 cGy dose (V10) from 55.2 to 40.7 cm 3 (p = 0.0013). The dose coverage as measured by volume receiving >95% of the prescription dose (V95%) of the WB without a 5 mm superficial layer decreases by only 0.74% (p = 0.0002) and the V95% for the tumor bed with 1.5 cm margin remains unchanged. Conclusions: This study has demonstrated the feasibility of using a SVM-based algorithm to determine optimal beam placement without a physician's intervention. The proposed method reduced the dose to OARs, especially for supine treated patients, without any relevant degradation of dose homogeneity and coverage in general.

An economic evaluation of the use of rare-earth screens to reduce the radiation dose from diagnostic x-ray procedures in Israel

International Nuclear Information System (INIS)

Ginzburg, G.M.; Schlesinger, T.; Ben-Shlomo, A.

1996-01-01

In contrasts, reducing the patient dose by using improved radiology equipment will often result in a constant reduction without further managerial effort for the lifetime of the equipment. Changing equipment is administratively far easier than altering long-established work practices. There are several methods available to achieve dose reduction in diagnostic radiology via this second category. For example, dose reductions of between 10% and 20% can be achieved independently by reducing attenuation between patient and image receptor to a minimum by means of carbon fiber components in couch tops, cassette fronts and anti-scatter grids [13-15]. Radiation dosage in film radiography can be reduced by approximately 50% by the use of rare- earth screens, which enable a faster film speed to be utilized (thus reducing exposure time) without significant loss in the diagnostic quality of the image. Rare-earth screens have been found in England to be the most cost-effective method of reducing dosage in film radiography, providing large dose reductions at considerably lower costs than carbon fiber components (authors)

An economic evaluation of the use of rare-earth screens to reduce the radiation dose from diagnostic x-ray procedures in Israel

Energy Technology Data Exchange (ETDEWEB)

Ginzburg, G M [Ministry of Health, Tel Aviv (Israel); Schlesinger, T; Ben-Shlomo, A [Israel Atomic Energy Commission, Yavne (Israel). Soreq Nuclear Research Center

1996-12-01

In contrasts, reducing the patient dose by using improved radiology equipment will often result in a constant reduction without further managerial effort for the lifetime of the equipment. Changing equipment is administratively far easier than altering long-established work practices. There are several methods available to achieve dose reduction in diagnostic radiology via this second category. For example, dose reductions of between 10% and 20% can be achieved independently by reducing attenuation between patient and image receptor to a minimum by means of carbon fiber components in couch tops, cassette fronts and anti-scatter grids [13-15]. Radiation dosage in film radiography can be reduced by approximately 50% by the use of rare- earth screens, which enable a faster film speed to be utilized (thus reducing exposure time) without significant loss in the diagnostic quality of the image. Rare-earth screens have been found in England to be the most cost-effective method of reducing dosage in film radiography, providing large dose reductions at considerably lower costs than carbon fiber components (authors).

Vector bileptons and the decays h→γγ,Zγ

Energy Technology Data Exchange (ETDEWEB)

Yue, Chong-Xing, E-mail: cxyue@lnnu.edu.cn; Shi, Qiu-Yang; Hua, Tian

2013-11-21

Taking into account of the constraints on the relevant parameters from the muon anomalous magnetic moment, we consider the contributions of the vector bileptons V{sup ±} and U{sup ±±} predicted by the reduced minimal 331 model to the Higgs decay channels h→γγ and Zγ. Our numerical results show that the vector bileptons can enhance the partial width Γ(h→γγ), while reduce the partial width Γ(h→Zγ), which are anti-correlated. With reasonable values of the relevant free parameters, the vector bileptons can explain the LHC data for the γγ signal. If the CMS data persists, the values of the free parameters λ{sub 2} and λ{sub 3} should be severe constrained.

Understanding reduced inorganic mercury accumulation in rice following selenium application: Selenium application routes, speciation and doses.

Science.gov (United States)

Tang, Wenli; Dang, Fei; Evans, Douglas; Zhong, Huan; Xiao, Lin

2017-02-01

Selenium (Se) has recently been demonstrated to reduce inorganic mercury (IHg) accumulation in rice plants, while its mechanism is far from clear. Here, we aimed at exploring the potential effects of Se application routes (soil or foliar application with Se), speciation (selenite and selenate), and doses on IHg-Se antagonistic interactions in soil-rice systems. Results of our pot experiments indicated that soil application but not foliar application could evidently reduce tissue IHg concentrations (root: 0-48%, straw: 15-58%, and brown rice: 26-74%), although both application routes resulted in comparable Se accumulation in aboveground tissues. Meanwhile, IHg distribution in root generally increased with amended Se doses in soil, suggesting antagonistic interactions between IHg and Se in root. These results provided initial evidence that IHg-Se interactions in the rhizosphere (i.e., soil or rice root), instead of those in the aboveground tissues, could probably be more responsible for the reduced IHg bioaccumulation following Se application. Furthermore, Se dose rather than Se speciation was found to be more important in controlling IHg accumulation in rice. Our findings regarding the importance of IHg-Se interactions in the rhizosphere, together with the systematic investigation of key factors affecting IHg-Se antagonism and IHg bioaccumulation, advance our understanding of Hg dynamics in soil-rice systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

A programme to reduce down-time and site radiation dose through improvements in control rod design

International Nuclear Information System (INIS)

Izatt, J.A.; Scobie, J.

1983-01-01

In many nuclear facilities a high proportion of the total radiation dose to staff may be ascribed to very few routine operations. Often this critical operation will require significant shut-down time, both to perform the function itself and to allow sufficient decay time to reduce radiation levels to acceptable values. This situation arises on the UTR-300 reactor at S.U.R.R.C., where over the twenty years of operation it has been found necessary to carry out preventive, and on some occasions remedial, maintenance at least once per year on the in-core elements of the control rod assemblies. This had led inevitably to reduced availability of the reactor and to significant overall radiation doses to the few long-serving staff members who carry out this work. The source of the problem seems to lie in the basic design of the assemblies, which may have been adequate for the original 10 KW versions of this reactor, but has proven to be deficient in several respects at the present 300 KW operating level. In an attempt to reduce down-time and radiation dose to staff a radical re-design of the control assemblies was undertaken in-house, and a conversion programme has been underway over the last two years. Details of the design improvements are presented with a discussion of the operating experience to date. (author)

A critical review of measures to reduce radioactive doses from drinking water and consumption of freshwater foodstuffs

International Nuclear Information System (INIS)

Smith, J.T.; Voitsekhovitch, O.V.; Haakanson, L.; Hilton, J.

2001-01-01

Following a radioactive fallout event, there are a number of possible intervention measures to reduce radioactive doses to the public via the surface water pathway. We have critically reviewed the options available to decision-makers in the event of radioactive contamination of surface waters. We believe that the most effective and viable measures to reduce radioactivity in drinking water are those which operate at the water treatment and distribution stage. Intervention measures to reduce concentrations of radioactivity in rivers and reservoirs are expected to be much less viable and efficient at reducing doses via the drinking water pathway. Bans on consumption of freshwater fish can be effective, but there are few viable measures to reduce radioactivity in fish prior to the preparation stage. Lake liming and biomanipulation have been found to be ineffective for radiocaesium, although the addition of potassium to lakewaters appears promising in some situations. Lake liming may be effective in reducing radiostrontium in fish, though this has not, to our knowledge, been tested. De-boning fish contaminated by strontium is probably the most effective food preparation measure, but salting and freezing can also reduce radiocaesium concentrations in fish. The provision of accurate information to the public is highlighted as a key element of countermeasure implementation

Reducing Radiation Dose in Coronary Angiography and Angioplasty Using Image Noise Reduction Technology.

Science.gov (United States)

Kastrati, Mirlind; Langenbrink, Lukas; Piatkowski, Michal; Michaelsen, Jochen; Reimann, Doris; Hoffmann, Rainer

2016-08-01

This study sought to quantitatively evaluate the reduction of radiation dose in coronary angiography and angioplasty with the use of image noise reduction technology in a routine clinical setting. Radiation dose data from consecutive 605 coronary procedures (397 consecutive coronary angiograms and 208 consecutive coronary interventions) performed from October 2014 to April 2015 on a coronary angiography system with noise reduction technology (Allura Clarity IQ) were collected. For comparison, radiation dose data from consecutive 695 coronary procedures (435 coronary angiograms and 260 coronary interventions) performed on a conventional coronary angiography system from October 2013 to April 2014 were evaluated. Patient radiation dosage was evaluated based on the cumulative dose area product. Operators and operator practice did not change between the 2 evaluated periods. Patient characteristics were collected to evaluate similarity of patient groups. Image quality was evaluated on a 5-grade scale in 30 patients of each group. There were no significant differences between the 2 evaluated groups in gender, age, weight, and fluoroscopy time (6.8 ± 6.1 vs 6.9 ± 6.3 minutes, not significant). The dose area product was reduced from 3195 ± 2359 to 983 ± 972 cGycm(2) (65%, p technology. Image quality was graded as similar between the evaluated systems (4.0 ± 0.7 vs 4.2 ± 0.6, not significant). In conclusion, a new x-ray technology with image noise reduction algorithm provides a substantial reduction in radiation exposure without the need to prolong the procedure or fluoroscopy time. Copyright © 2016 Elsevier Inc. All rights reserved.

Actions taken in order to reduce doses to workers in PWR power plants

International Nuclear Information System (INIS)

Jeanson, P.

1978-01-01

The dose limitation for workers in nuclear power plants is a permanent aim of Electricite de France. Many ways are followed at the same time to reach it, some of them in collaboration with C.E.A. Theoretical studies concern mostly sources and transfers of corrosion and fission products in the primary circuit of pressurized water reactors as well as the means for reducing the deposited activity. Practical studies concern design problems for equipment and buildings. They try to specify rules for these purposes. They also concern maintenance conditions of all components: for the most important components, special tools are designed. At last, studies and experimentation of daily dosimetry should bring a better knowledge of the distribution of collective doses and, subsequently, should give a better idea of the actions to be undertaken [fr

Current vector control challenges in the fight against malaria.

Science.gov (United States)

Benelli, Giovanni; Beier, John C

2017-10-01

The effective and eco-friendly control of Anopheles vectors plays a key role in any malaria management program. Integrated Vector Management (IVM) suggests making use of the full range of vector control tools available. The strategies for IVM require novel technologies to control outdoor transmission of malaria. Despite the wide number of promising control tools tested against mosquitoes, current strategies for malaria vector control used in most African countries are not sufficient to achieve successful malaria control. The majority of National Malaria Control Programs in Africa still rely on indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs). These methods reduce malaria incidence but generally have little impact on malaria prevalence. In addition to outdoor transmission, growing levels of insecticide resistance in targeted vectors threaten the efficacy of LLINs and IRS. Larvicidal treatments can be useful, but are not recommended for rural areas. The research needed to improve the quality and delivery of mosquito vector control should focus on (i) optimization of processes and methods for vector control delivery; (ii) monitoring of vector populations and biting activity with reliable techniques; (iii) the development of effective and eco-friendly tools to reduce the burden or locally eliminate malaria and other mosquito-borne diseases; (iv) the careful evaluation of field suitability and efficacy of new mosquito control tools to prove their epidemiological impact; (v) the continuous monitoring of environmental changes which potentially affect malaria vector populations; (vi) the cooperation among different disciplines, with main emphasis on parasitology, tropical medicine, ecology, entomology, and ecotoxicology. A better understanding of behavioral ecology of malaria vectors is required. Key ecological obstacles that limit the effectiveness of vector control include the variation in mosquito behavior, development of insecticide resistance

Accounting for shared and unshared dosimetric uncertainties in the dose response for ultrasound-detected thyroid nodules after exposure to radioactive fallout.

Science.gov (United States)

Land, Charles E; Kwon, Deukwoo; Hoffman, F Owen; Moroz, Brian; Drozdovitch, Vladimir; Bouville, André; Beck, Harold; Luckyanov, Nicholas; Weinstock, Robert M; Simon, Steven L

2015-02-01

Dosimetic uncertainties, particularly those that are shared among subgroups of a study population, can bias, distort or reduce the slope or significance of a dose response. Exposure estimates in studies of health risks from environmental radiation exposures are generally highly uncertain and thus, susceptible to these methodological limitations. An analysis was published in 2008 concerning radiation-related thyroid nodule prevalence in a study population of 2,994 villagers under the age of 21 years old between August 1949 and September 1962 and who lived downwind from the Semipalatinsk Nuclear Test Site in Kazakhstan. This dose-response analysis identified a statistically significant association between thyroid nodule prevalence and reconstructed doses of fallout-related internal and external radiation to the thyroid gland; however, the effects of dosimetric uncertainty were not evaluated since the doses were simple point "best estimates". In this work, we revised the 2008 study by a comprehensive treatment of dosimetric uncertainties. Our present analysis improves upon the previous study, specifically by accounting for shared and unshared uncertainties in dose estimation and risk analysis, and differs from the 2008 analysis in the following ways: 1. The study population size was reduced from 2,994 to 2,376 subjects, removing 618 persons with uncertain residence histories; 2. Simulation of multiple population dose sets (vectors) was performed using a two-dimensional Monte Carlo dose estimation method; and 3. A Bayesian model averaging approach was employed for evaluating the dose response, explicitly accounting for large and complex uncertainty in dose estimation. The results were compared against conventional regression techniques. The Bayesian approach utilizes 5,000 independent realizations of population dose vectors, each of which corresponds to a set of conditional individual median internal and external doses for the 2,376 subjects. These 5,000 population

Can low-dose CT with iterative reconstruction reduce both the radiation dose and the amount of iodine contrast medium in a dynamic CT study of the liver?

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Hiroto; Okada, Masahiro; Hyodo, Tomoko; Hidaka, Syojiro; Kagawa, Yuki; Matsuki, Mitsuru; Tsurusaki, Masakatsu; Murakami, Takamichi, E-mail: murakami@med.kindai.ac.jp

2014-04-15

Purpose: To investigate whether low-dose dynamic CT of the liver with iterative reconstruction can reduce both the radiation dose and the amount of contrast medium. Materials and methods: This study was approved by our institutional review board. 113 patients were randomly assigned to one of two groups. Group A/group B (fifty-eight/fifty-five patients) underwent liver dynamic CT at 120/100 kV, with 0/40% adaptive statistical iterative reconstruction (ASIR), with a contrast dose of 600/480 mg I/kg, respectively. Radiation exposure was estimated based on the manufacturer's phantom data. The enhancement value of the hepatic parenchyma, vessels and the tumor-to-liver contrast of hepatocellular carcinomas (HCCs) were compared between two groups. Two readers independently assessed the CT images of the hepatic parenchyma and HCCs. Results: The mean CT dose indices: 6.38/4.04 mGy, the dose-length products: 194.54/124.57 mGy cm, for group A/group B. The mean enhancement value of the hepatic parenchyma and the tumor-to-liver contrast of HCCs with diameters greater than 1 cm in the post-contrast all phases did not differ significantly between two groups (P > 0.05). The enhancement values of vessels in group B were significantly higher than that in group A in the delayed phases (P < 0.05). Two reader's confidence levels for the hepatic parenchyma in the delayed phases and HCCs did not differ significantly between the groups (P > 0.05). Conclusions: Low-dose dynamic CT with ASIR can reduce both the radiation dose and the amount of contrast medium without image quality degradation, compared to conventional dynamic CT without ASIR.

Environmental management: a re-emerging vector control strategy.

Science.gov (United States)

Ault, S K

1994-01-01

Vector control may be accomplished by environmental management (EM), which consists of permanent or long-term modification of the environment, temporary or seasonal manipulation of the environment, and modifying or changing our life styles and practices to reduce human contact with infective vectors. The primary focus of this paper is EM in the control of human malaria, filariasis, arboviruses, Chagas' disease, and schistosomiasis. Modern EM developed as a discipline based primarily in ecologic principles and lessons learned from the adverse environmental impacts of rural development projects. Strategies such as the suppression of vector populations through the provision of safe water supplies, proper sanitation, solid waste management facilities, sewerage and excreta disposal systems, water manipulation in dams and irrigation systems, vector diversion by zooprophylaxis, and vector exclusion by improved housing, are discussed with appropriate examples. Vectors of malaria, filariasis, Chagas' disease, and schistosomiasis have been controlled by drainage or filling aquatic breeding sites, improved housing and sanitation, the use of expanded polystyrene beads, zooprophylaxis, or the provision of household water supplies. Community participation has been effective in the suppression of dengue vectors in Mexico and the Dominican Republic. Alone or combined with other vector control methods, EM has been proven to be a successful approach to vector control in a number of places. The future of EM in vector control looks promising.

Killing tensors and conformal Killing tensors from conformal Killing vectors

International Nuclear Information System (INIS)

Rani, Raffaele; Edgar, S Brian; Barnes, Alan

2003-01-01

Koutras has proposed some methods to construct reducible proper conformal Killing tensors and Killing tensors (which are, in general, irreducible) when a pair of orthogonal conformal Killing vectors exist in a given space. We give the completely general result demonstrating that this severe restriction of orthogonality is unnecessary. In addition, we correct and extend some results concerning Killing tensors constructed from a single conformal Killing vector. A number of examples demonstrate that it is possible to construct a much larger class of reducible proper conformal Killing tensors and Killing tensors than permitted by the Koutras algorithms. In particular, by showing that all conformal Killing tensors are reducible in conformally flat spaces, we have a method of constructing all conformal Killing tensors, and hence all the Killing tensors (which will in general be irreducible) of conformally flat spaces using their conformal Killing vectors

Emerging Vector-Borne Diseases - Incidence through Vectors.

Science.gov (United States)

Savić, Sara; Vidić, Branka; Grgić, Zivoslav; Potkonjak, Aleksandar; Spasojevic, Ljubica

2014-01-01

Vector-borne diseases use to be a major public health concern only in tropical and subtropical areas, but today they are an emerging threat for the continental and developed countries also. Nowadays, in intercontinental countries, there is a struggle with emerging diseases, which have found their way to appear through vectors. Vector-borne zoonotic diseases occur when vectors, animal hosts, climate conditions, pathogens, and susceptible human population exist at the same time, at the same place. Global climate change is predicted to lead to an increase in vector-borne infectious diseases and disease outbreaks. It could affect the range and population of pathogens, host and vectors, transmission season, etc. Reliable surveillance for diseases that are most likely to emerge is required. Canine vector-borne diseases represent a complex group of diseases including anaplasmosis, babesiosis, bartonellosis, borreliosis, dirofilariosis, ehrlichiosis, and leishmaniosis. Some of these diseases cause serious clinical symptoms in dogs and some of them have a zoonotic potential with an effect to public health. It is expected from veterinarians in coordination with medical doctors to play a fundamental role at primarily prevention and then treatment of vector-borne diseases in dogs. The One Health concept has to be integrated into the struggle against emerging diseases. During a 4-year period, from 2009 to 2013, a total number of 551 dog samples were analyzed for vector-borne diseases (borreliosis, babesiosis, ehrlichiosis, anaplasmosis, dirofilariosis, and leishmaniasis) in routine laboratory work. The analysis was done by serological tests - ELISA for borreliosis, dirofilariosis, and leishmaniasis, modified Knott test for dirofilariosis, and blood smear for babesiosis, ehrlichiosis, and anaplasmosis. This number of samples represented 75% of total number of samples that were sent for analysis for different diseases in dogs. Annually, on average more then half of the samples

Evaluating proton stereotactic body radiotherapy to reduce chest wall dose in the treatment of lung cancer

Energy Technology Data Exchange (ETDEWEB)

Welsh, James, E-mail: jwelsh@mdanderson.org [Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, TX (United States); Amini, Arya [Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, TX (United States); UC Irvine School of Medicine, Irvine, CA (United States); Ciura, Katherine; Nguyen, Ngoc; Palmer, Matt [Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, TX (United States); Soh, Hendrick [Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, TX (United States); Department of Radiation Physics, The University of Texas, MD Anderson Cancer Center, Houston, TX (United States); Allen, Pamela K.; Paolini, Michael; Liao, Zhongxing [Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, TX (United States); Bluett, Jaques; Mohan, Radhe [Department of Radiation Physics, The University of Texas, MD Anderson Cancer Center, Houston, TX (United States); Gomez, Daniel; Cox, James D.; Komaki, Ritsuko; Chang, Joe Y. [Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, TX (United States)

2013-01-01

Stereotactic body radiotherapy (SBRT) can produce excellent local control of several types of solid tumor; however, toxicity to nearby critical structures is a concern. We found previously that in SBRT for lung cancer, the chest wall (CW) volume receiving 20, 30, or 40 Gy (V{sub 20}, V{sub 30}, or V{sub 40}) was linked with the development of neuropathy. Here we sought to determine whether the dosimetric advantages of protons could produce lower CW doses than traditional photon-based SBRT. We searched an institutional database to identify patients treated with photon SBRT for lung cancer with tumors within < 2.5 cm of the CW. We found 260 cases; of these, chronic grade ≥ 2 CW pain was identified in 23 patients. We then selected 10 representative patients from this group and generated proton SBRT treatment plans, using the identical dose of 50 Gy in 4 fractions, and assessed potential differences in CW dose between the 2 plans. The proton SBRT plans reduced the CW doses at all dose levels measured. The median CW V{sub 20} was 364.0 cm{sup 3} and 160.0 cm{sup 3} (p < 0.0001), V{sub 30} was 144.6 cm{sup 3}vs 77.0 cm{sup 3} (p = 0.0012), V{sub 35} was 93.9 cm{sup 3}vs 57.9 cm{sup 3} (p = 0.005), V{sub 40} was 66.5 cm{sup 3}vs 45.4 cm{sup 3} (p = 0.0112), and mean lung dose was 5.9 Gy vs 3.8 Gy (p = 0.0001) for photons and protons, respectively. Coverage of the planning target volume (PTV) was comparable between the 2 sets of plans (96.4% for photons and 97% for protons). From a dosimetric standpoint, proton SBRT can achieve the same coverage of the PTV while significantly reducing the dose to the CW and lung relative to photon SBRT and therefore may be beneficial for the treatment of lesions closer to critical structures.

VEST: Abstract vector calculus simplification in Mathematica

Science.gov (United States)

Squire, J.; Burby, J.; Qin, H.

2014-01-01

We present a new package, VEST (Vector Einstein Summation Tools), that performs abstract vector calculus computations in Mathematica. Through the use of index notation, VEST is able to reduce three-dimensional scalar and vector expressions of a very general type to a well defined standard form. In addition, utilizing properties of the Levi-Civita symbol, the program can derive types of multi-term vector identities that are not recognized by reduction, subsequently applying these to simplify large expressions. In a companion paper Burby et al. (2013) [12], we employ VEST in the automation of the calculation of high-order Lagrangians for the single particle guiding center system in plasma physics, a computation which illustrates its ability to handle very large expressions. VEST has been designed to be simple and intuitive to use, both for basic checking of work and more involved computations.

Vector analysis

CERN Document Server

Newell, Homer E

2006-01-01

When employed with skill and understanding, vector analysis can be a practical and powerful tool. This text develops the algebra and calculus of vectors in a manner useful to physicists and engineers. Numerous exercises (with answers) not only provide practice in manipulation but also help establish students' physical and geometric intuition in regard to vectors and vector concepts.Part I, the basic portion of the text, consists of a thorough treatment of vector algebra and the vector calculus. Part II presents the illustrative matter, demonstrating applications to kinematics, mechanics, and e

A Novel Dose Constraint to Reduce Xerostomia in Head-and-Neck Cancer Patients Treated With Intensity-Modulated Radiotherapy

International Nuclear Information System (INIS)

Strigari, Lidia; Benassi, Marcello; Arcangeli, Giorgio; Bruzzaniti, Vicente; Giovinazzo, Giuseppe; Marucci, Laura

2010-01-01

Purpose: To investigate the predictors of incidence and duration of xerostomia (XT) based on parotid glands (PG), submandibular glands (SMG), and both glands taken as a whole organ (TG) in head-and-neck cancer patients treated with intensity-modulated radiotherapy. Methods and Materials: A prospective study was initiated in May 2003. Sixty-three head-and-neck patients (44 with nasopharynx cancer) were included in the analysis. Using the dose-volume histogram the PG, SMG, and TG mean doses were calculated. Unstimulated and stimulated salivary flow were measured and XT-related questionnaires were compiled before and at 3, 6, 12, 18, and 24 months after radiotherapy. Salivary gland toxicity was evaluated using the Radiation Therapy Oncology Group scale, and Grade ≥3 toxicity was used as the endpoint. The XT incidence was investigated according to descriptive statistics and univariate and multivariate analysis. The Bonferroni method was used for multiple comparison adjustment. Results: After a reduced flow at 3 months after radiotherapy, recovery of salivary flow was observed over time. Primary site and salivary gland mean doses and volumes were identified in univariate analysis as prognostic factors. Multivariate analysis confirmed that TG mean dose (p = 0.00066) and pretreatment stimulated salivary flow (p = 0.00420) are independent factors for predicting XT. Conclusion: The TG mean dose correlates with XT as assessed by Radiation Therapy Oncology Group criteria, salivary output, and XT-related questionnaires. Our results suggest that TG mean dose is a candidate dose constraint for reducing XT, requiring considerably more validation in non-nasopharyngeal cancer patients.

Vector-Tensor and Vector-Vector Decay Amplitude Analysis of B0→φK*0

International Nuclear Information System (INIS)

Aubert, B.; Bona, M.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Tisserand, V.; Zghiche, A.; Grauges, E.; Palano, A.; Chen, J. C.; Qi, N. D.; Rong, G.; Wang, P.; Zhu, Y. S.; Eigen, G.; Ofte, I.; Stugu, B.; Abrams, G. S.

2007-01-01

We perform an amplitude analysis of the decays B 0 →φK 2 * (1430) 0 , φK * (892) 0 , and φ(Kπ) S-wave 0 with a sample of about 384x10 6 BB pairs recorded with the BABAR detector. The fractions of longitudinal polarization f L of the vector-tensor and vector-vector decay modes are measured to be 0.853 -0.069 +0.061 ±0.036 and 0.506±0.040±0.015, respectively. Overall, twelve parameters are measured for the vector-vector decay and seven parameters for the vector-tensor decay, including the branching fractions and parameters sensitive to CP violation

Duration of the vector period of house flies for Campylobacter jejuni estimated by experimental infection series

DEFF Research Database (Denmark)

Skovgård, Henrik; Hald, Birthe

The house fly Musca domestica may act as a vector and transmit Campylobacter to broiler flocks. We determined the duration of the vector period for C. jejuni at various temperatures and inoculation doses. For the temperature experiment, laboratory reared house flies (n = 375) were inoculated with...

Bolus effect to reduce skin dose of the caontralateral breast during breast cancer radiation therapy

Energy Technology Data Exchange (ETDEWEB)

Won, Young Jin [Dept. of Radiation Oncology, InJe University Ilsan Paik Hospital, Goyang (Korea, Republic of); Kim, Jong Won; Kim, Jung Hoon [Dept. of Radiology, Radiation Oncology, KonYang University Hospital, Daejeon (Korea, Republic of)

2017-06-15

The aim of this study was to evaluate the dose comparison using Radon phantom with 5 mm and 10 mm tissue equivalent materials, FIF, Wedge(15, 30 angle) and IMRT, to reduce the skin dose of the contralateral breast during breast cancer radiation therapy(Total dose: 50.4Gy). The dose was measured for each treatment plan by attaching to the 8 point of the contralateral breast of the treated region using a optical-stimulated luminance dosimeter(OSLD) as a comparative dose evaluation method. Of the OSLD used in the study, 10 were used with reproducibility within 3%. As a result, the average reduction rates of 5 mm and 10 mm in the FIF treatment plan were 37.23 cGy and 41.77 cGy, respectively, and the average reduction rates in the treatment plan using Wedge 15 degrees were 70.69 cGy and 87.57 cGy, respectively. The IMRT showed a reduction of 67.37 cGy and 83.17 cGy, respectively. The results of using bolus showed that as the thickness of the bolus increased in all treatments, the dose reduction increased. We concluded that mastectomy as well as general radiotherapy for breast cancer would be very effective for patients who are more likely to be exposed to scattered radiation due to a more demanding or complex treatment plan.

Study on construction of pEgr-hPTEN expression vector induced by irradiation and its anti-tumor effect in vitro

International Nuclear Information System (INIS)

Tian Mei; Jin Guanghui; Piao Chunji; Li Xiuyi; Liu Linlin

2003-01-01

Objective: To clone the cDNA of human tumor suppressor gene-PTEN, construct pEgr-hPTEN expression vector induced by irradiation and study its inhibitory effect on proliferation of malignant glioma cell line SHG-44 transfected steadily with pEgr-hPTEN after different doses of X-ray irradiation. Methods: A DNA fragment about 1200 bp, PTEN, was amplified from human placenta tissues by using RT-nested PCR and was cloned into pUCm-T vector after automatic sequencing, then the fragment was inserted into a vector pcD-NA3.1-Egr to construct an expression vector pEgr-hPTEN. pEgr-hPTEN was transfected into SHG-44 cells in vitro. Stably transfected cell line SHG-44-sPTEN was selected through G418. The inhibitor effect on SHG-44-sPTEN was observed after different doses of X-ray irradiation in vitro. Results: The PTEN cDNA has been cloned correctly and its expression vector pEgr-hPTEN was also constructed. Growth of SHG-44 cells was inhibited significantly by stable pEgr-hPTEN transfection combined with X-ray irradiation. With the increase of dose, the inhibitory effect was enhanced within 5 Gy. Conclusion: Human tumor suppressor gene-PTEN cDNA has been cloned and its expression vector has been constructed. The tumor was inhibited significantly by gene-radiotherapy in vitro. The result provides the theoretical and experimental basis for improvement of clinical radiotherapeutic effect on tumors

About vectors

CERN Document Server

Hoffmann, Banesh

1975-01-01

From his unusual beginning in ""Defining a vector"" to his final comments on ""What then is a vector?"" author Banesh Hoffmann has written a book that is provocative and unconventional. In his emphasis on the unresolved issue of defining a vector, Hoffmann mixes pure and applied mathematics without using calculus. The result is a treatment that can serve as a supplement and corrective to textbooks, as well as collateral reading in all courses that deal with vectors. Major topics include vectors and the parallelogram law; algebraic notation and basic ideas; vector algebra; scalars and scalar p

Reduced dose of salvage-line regorafenib monotherapy for metastatic colorectal cancer in Japan.

Science.gov (United States)

Hirano, Gen; Makiyama, Akitaka; Makiyama, Chinatsu; Esaki, Taito; Oda, Hisanobu; Uchino, Keita; Komoda, Masato; Tanaka, Risa; Matsushita, Yuzo; Mitsugi, Kenji; Shibata, Yoshihiro; Kumagai, Hozumi; Arita, Shuji; Ariyama, Hiroshi; Kusaba, Hitoshi; Akashi, Koichi; Baba, Eishi

2015-01-01

Salvage-line regorafenib monotherapy exhibited a marked survival benefit for metastatic colorectal cancer (mCRC). However, the toxicity of this regimen has resulted in the clinical use of a reduced dose of regorafenib. Thirty-two Japanese mCRC patients (median age=61 years) who had been treated with regorafenib were retrospectively examined. Best objective response rate was 0% and stable disease (SD) was 31%. Median progression-free survival was 81 days and median overall survival was 233 days. Adverse events of any grade were observed in all patients: 17 (53%) patients suffered grade 3 or 4 adverse events including fatigue (13%), anorexia (13%), hand-foot skin reaction (22%) and elevations of alanine aminotransferase/aspartate aminotransferase (19%/16%). One patient with grade 5 liver dysfunction was identified (3%). Twenty-nine (91%) patients required treatment dose reduction or a delay in treatment. The relative dose intensity was 59%. Regorafenib treatments were terminated because of disease progression (59%) or adverse events (34%). Despite a decrease in the intensity of regorafenib treatment, because of severe adverse events, a fairly favorable efficacy was achieved in Japanese patients. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Mixture for Controlling Insecticide-Resistant Malaria Vectors

OpenAIRE

Pennetier, Cédric; Costantini, Carlo; Corbel, Vincent; Licciardi, Séverine; Dabire, R. K.; Lapied, B.; Chandre, Fabrice; Hougard, Jean-Marc

2008-01-01

The spread of resistance to pyrethroids in the major Afrotropical malaria vectors Anopheles gambiae s.s. necessitates the development of new strategies to control resistant mosquito populations. To test the efficacy of nets treated with repellent and insecticide against susceptible and insecticide-resistant An. gambiae mosquito populations, we impregnated mosquito bed nets with an insect repellent mixed with a low dose of organophosphorous insecticide and tested them in a rice-growing area ne...

Vector models and generalized SYK models

Energy Technology Data Exchange (ETDEWEB)

Peng, Cheng [Department of Physics, Brown University,Providence RI 02912 (United States)

2017-05-23

We consider the relation between SYK-like models and vector models by studying a toy model where a tensor field is coupled with a vector field. By integrating out the tensor field, the toy model reduces to the Gross-Neveu model in 1 dimension. On the other hand, a certain perturbation can be turned on and the toy model flows to an SYK-like model at low energy. A chaotic-nonchaotic phase transition occurs as the sign of the perturbation is altered. We further study similar models that possess chaos and enhanced reparameterization symmetries.

Mouse Mammary Tumor Virus Promoter-Containing Retroviral Promoter Conversion Vectors for Gene-Directed Enzyme Prodrug Therapy are Functional in Vitro and in Vivo

Directory of Open Access Journals (Sweden)

Reinhard Klein

2008-01-01

Full Text Available Gene directed-enzyme prodrug therapy (GDEPT is an approach for sensitization of tumor cells to an enzymatically activated, otherwise nontoxic, prodrug. Cytochrome P450 2B1 (CYP2B1 metabolizes the prodrugs cyclophosphamide (CPA and ifosfamide (IFA to produce the cytotoxic substances phosphoramide mustard and isophosphoramide mustard as well as the byproduct acrolein. We have constructed a retroviral promoter conversion (ProCon vector for breast cancer GDEPT. The vector allows expression of CYP2B1 from the mouse mammary tumor virus (MMTV promoter known to be active in the mammary glands of transgenic animals. It is anticipated to be used for the generation of encapsulated viral vector producing cells which, when placed inside or close to a tumor, will act as suppliers of the therapeutic CYP2B1 protein as well as of the therapeutic vector itself. The generated vector was effectively packaged by virus producing cells and allowed the production of high levels of enzymatically active CYP2B1 in infected cells which sensitized them to killing upon treatment with both IFA and CPA. Determination of the respective IC50 values demonstrated that the effective IFA dose was reduced by sixteen folds. Infection efficiencies in vivo were determined using a reporter gene-bearing vector in a mammary cancer cell-derived xenograft tumor mouse model.

Diagnostic accuracy at several reduced radiation dose levels for CT imaging in the diagnosis of appendicitis

Science.gov (United States)

Zhang, Di; Khatonabadi, Maryam; Kim, Hyun; Jude, Matilda; Zaragoza, Edward; Lee, Margaret; Patel, Maitraya; Poon, Cheryce; Douek, Michael; Andrews-Tang, Denise; Doepke, Laura; McNitt-Gray, Shawn; Cagnon, Chris; DeMarco, John; McNitt-Gray, Michael

2012-03-01

Purpose: While several studies have investigated the tradeoffs between radiation dose and image quality (noise) in CT imaging, the purpose of this study was to take this analysis a step further by investigating the tradeoffs between patient radiation dose (including organ dose) and diagnostic accuracy in diagnosis of appendicitis using CT. Methods: This study was IRB approved and utilized data from 20 patients who underwent clinical CT exams for indications of appendicitis. Medical record review established true diagnosis of appendicitis, with 10 positives and 10 negatives. A validated software tool used raw projection data from each scan to create simulated images at lower dose levels (70%, 50%, 30%, 20% of original). An observer study was performed with 6 radiologists reviewing each case at each dose level in random order over several sessions. Readers assessed image quality and provided confidence in their diagnosis of appendicitis, each on a 5 point scale. Liver doses at each case and each dose level were estimated using Monte Carlo simulation based methods. Results: Overall diagnostic accuracy varies across dose levels: 92%, 93%, 91%, 90% and 90% across the 100%, 70%, 50%, 30% and 20% dose levels respectively. And it is 93%, 95%, 88%, 90% and 90% across the 13.5-22mGy, 9.6-13.5mGy, 6.4-9.6mGy, 4-6.4mGy, and 2-4mGy liver dose ranges respectively. Only 4 out of 600 observations were rated "unacceptable" for image quality. Conclusion: The results from this pilot study indicate that the diagnostic accuracy does not change dramatically even at significantly reduced radiation dose.

Effects of azadirachtin on the biology of Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae) adult female, the main vector of American visceral leishmaniasis.

Science.gov (United States)

De Andrade-Coelho, Cláudia Alves; De Souza, Nataly Araujo; Silva, Vanderlei Campos; Souza, Adelson A; Gonzalez, Marcelo Salabert; Rangel, Elizabeth Ferreira

2014-07-01

The effects of azadirachtin A added to the sucrose diet of the adult females on the mortality, oviposition, and hatching of the sand fly vector of American visceral leishmaniasis Lutzomyia longipalpis (Lutz & Neiva, 1912) were investigated. Concentrations of 0.1, 1.0, and 10.0 microg/mg of azadirachtin significantly increased insect mortality in comparison with control insects. The same dose also significantly reduced oviposition but not hatching. After a long development period, significantly fewer adult insects were obtained from eggs hatching by azadirachtin-treated females in a dose-response manner. These results indicate that azadirachtin is a potent sterilizer that could be used against the development of Lu. longipalpis populations and as a tool for studying physiological and biochemical processes in phlebotomine species.

Peridomestic Aedes malayensis and Aedes albopictus are capable vectors of arboviruses in cities.

Science.gov (United States)

Mendenhall, Ian H; Manuel, Menchie; Moorthy, Mahesh; Lee, Theodore T M; Low, Dolyce H W; Missé, Dorothée; Gubler, Duane J; Ellis, Brett R; Ooi, Eng Eong; Pompon, Julien

2017-06-01

Dengue and chikungunya are global re-emerging mosquito-borne diseases. In Singapore, sustained vector control coupled with household improvements reduced domestic mosquito populations for the past 45 years, particularly the primary vector Aedes aegypti. However, while disease incidence was low for the first 30 years following vector control implementation, outbreaks have re-emerged in the past 15 years. Epidemiological observations point to the importance of peridomestic infection in areas not targeted by control programs. We investigated the role of vectors in peri-domestic areas. We carried out entomological surveys to identify the Aedes species present in vegetated sites in highly populated areas and determine whether mosquitoes were present in open-air areas frequented by people. We compared vector competence of Aedes albopictus and Aedes malayensis with Ae. aegypti after oral infection with sympatric dengue serotype 2 and chikungunya viruses. Mosquito saliva was tested for the presence of infectious virus particles as a surrogate for transmission following oral infection. We identified Aedes albopictus and Aedes malayensis throughout Singapore and quantified their presence in forested and opened grassy areas. Both Ae. albopictus and Ae. malayensis can occupy sylvatic niches and were highly susceptible to both arboviruses. A majority of saliva of infected Ae. malayensis contained infectious particles for both viruses. Our study reveals the prevalence of competent vectors in peri-domestic areas, including Ae. malayensis for which we established the vector status. Epidemics can be driven by infection foci, which are epidemiologically enhanced in the context of low herd immunity, selective pressure on arbovirus transmission and the presence of infectious asymptomatic persons, all these conditions being present in Singapore. Learning from Singapore's vector control success that reduced domestic vector populations, but has not sustainably reduced arboviral incidence

PA positioning significantly reduces testicular dose during sacroiliac joint radiography

Energy Technology Data Exchange (ETDEWEB)

Mekis, Nejc [Faculty of Health Sciences, University of Ljubljana (Slovenia); Mc Entee, Mark F., E-mail: mark.mcentee@ucd.i [School of Medicine and Medical Science, University College Dublin 4 (Ireland); Stegnar, Peter [Jozef Stefan International Postgraduate School, Ljubljana (Slovenia)

2010-11-15

Radiation dose to the testes in the antero-posterior (AP) and postero-anterior (PA) projection of the sacroiliac joint (SIJ) was measured with and without a scrotal shield. Entrance surface dose, the dose received by the testicles and the dose area product (DAP) was used. DAP measurements revealed the dose received by the phantom in the PA position is 12.6% lower than the AP (p {<=} 0.009) with no statistically significant reduction in image quality (p {<=} 0.483). The dose received by the testes in the PA projection in SIJ imaging is 93.1% lower than the AP projection when not using protection (p {<=} 0.020) and 94.9% lower with protection (p {<=} 0.019). The dose received by the testicles was not changed by the use of a scrotal shield in the AP position (p {<=} 0.559); but was lowered by its use in the PA (p {<=} 0.058). Use of the PA projection in SIJ imaging significantly lowers, the dose received by the testes compared to the AP projection without significant loss of image quality.

Vectors

DEFF Research Database (Denmark)

Boeriis, Morten; van Leeuwen, Theo

2017-01-01

should be taken into account in discussing ‘reactions’, which Kress and van Leeuwen link only to eyeline vectors. Finally, the question can be raised as to whether actions are always realized by vectors. Drawing on a re-reading of Rudolf Arnheim’s account of vectors, these issues are outlined......This article revisits the concept of vectors, which, in Kress and van Leeuwen’s Reading Images (2006), plays a crucial role in distinguishing between ‘narrative’, action-oriented processes and ‘conceptual’, state-oriented processes. The use of this concept in image analysis has usually focused...

Phytoextract-induced developmental deformities in malaria vector.

Science.gov (United States)

Sharma, Preeti; Mohan, Lalit; Srivastava, C N

2006-09-01

Larvicidal potential of petroleum ether (Pee), carbon tetrachloride (Cte) and methanol extract (Mee) of Artemisia annua, Chenopodium album and Sonchus oleraceus was observed against malaria vector, Anopheles stephensi Liston. The Pee of A. annua with LC50 16.85 ppm after 24 h and 11.45 ppm after 48 h of treatment was found most effective, followed by Cte of A. annua and Ch. album, Pee of Ch. album and Mee of A. annua. However, no significant larvicidal activity was observed in Mee of Ch. album and all the three extracts of S. oleraceous. The Pee of A. annua was further investigated for its effect on the metamorphosis and the development of the malaria vector. It influenced the early life cycle of An. stephensi by reducing the percentage of hatching, larval, pupal and adult emergence and also lengthening the larval and pupal periods. The growth index was also reduced significantly. As the extract has remarkable effect on the metamorphosis and high larvicidal potential, it could, therefore, be used as an effective biocontrol agent against the highly nuisant malaria vector.

Longevity of rAAV vector and plasmid DNA in blood after intramuscular injection in nonhuman primates: implications for gene doping.

Science.gov (United States)

Ni, W; Le Guiner, C; Gernoux, G; Penaud-Budloo, M; Moullier, P; Snyder, R O

2011-07-01

Legitimate uses of gene transfer technology can benefit from sensitive detection methods to determine vector biodistribution in pre-clinical studies and in human clinical trials, and similar methods can detect illegitimate gene transfer to provide sports-governing bodies with the ability to maintain fairness. Real-time PCR assays were developed to detect a performance-enhancing transgene (erythropoietin, EPO) and backbone sequences in the presence of endogenous cellular sequences. In addition to developing real-time PCR assays, the steps involved in DNA extraction, storage and transport were investigated. By real-time PCR, the vector transgene is distinguishable from the genomic DNA sequence because of the absence of introns, and the vector backbone can be identified by heterologous gene expression control elements. After performance of the assays was optimized, cynomolgus macaques received a single dose by intramuscular (IM) injection of plasmid DNA, a recombinant adeno-associated viral vector serotype 1 (rAAV1) or a rAAV8 vector expressing cynomolgus macaque EPO. Macaques received a high plasmid dose intended to achieve a significant, but not life-threatening, increase in hematocrit. rAAV vectors were used at low doses to achieve a small increase in hematocrit and to determine the limit of sensitivity for detecting rAAV sequences by single-step PCR. DNA extracted from white blood cells (WBCs) was tested to determine whether WBCs can be collaterally transfected by plasmid or transduced by rAAV vectors in this context, and can be used as a surrogate marker for gene doping. We demonstrate that IM injection of a conventional plasmid and rAAV vectors results in the presence of DNA that can be detected at high levels in blood before rapid elimination, and that rAAV genomes can persist for several months in WBCs.

Reducing Radiation Doses in Female Breast and Lung during CT Examinations of Thorax: A new Technique in two Scanners

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Mehnati P.

2017-09-01

Full Text Available Background: Chest CT is a commonly used examination for the diagnosis of lung diseases, but a breast within the scanned field is nearly never the organ of interest. Objective: The purpose of this study is to compare the female breast and lung doses using split and standard protocols in chest CT scanning. Materials and Methods: The sliced chest and breast female phantoms were used. CT exams were performed using a single-slice (SS- and a 16 multi-slice (MS- CT scanner at 100 kVp and 120 kVp. Two different protocols, including standard and split protocols, were selected for scanning. The breast and lung doses were measured using thermo-luminescence dosimeters which were inserted into different layers of the chest and breast phantoms. The differences in breast and lung radiation doses in two protocols were studied in two scanners, analyzed by SPSS software and compared by t-test. Results: Breast dose by split scanning technique reduced 11% and 31% in SS- and MS- CT. Also, the radiation dose of lung tissue in this method decreased 18% and 54% in SS- and MS- CT, respectively. Moreover, there was a significant difference (p< 0.0001 in the breast and lung radiation doses between standard and split scanning protocols. Conclusion: The application of a split scan technique instead of standard protocol has a considerable potential to reduce breast and lung doses in SS- and MS- CT scanners. If split scanning protocol is associated with an optimum kV and MSCT, the maximum dose decline will be provided.

Vector regression introduced

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Mok Tik

2014-06-01

Full Text Available This study formulates regression of vector data that will enable statistical analysis of various geodetic phenomena such as, polar motion, ocean currents, typhoon/hurricane tracking, crustal deformations, and precursory earthquake signals. The observed vector variable of an event (dependent vector variable is expressed as a function of a number of hypothesized phenomena realized also as vector variables (independent vector variables and/or scalar variables that are likely to impact the dependent vector variable. The proposed representation has the unique property of solving the coefficients of independent vector variables (explanatory variables also as vectors, hence it supersedes multivariate multiple regression models, in which the unknown coefficients are scalar quantities. For the solution, complex numbers are used to rep- resent vector information, and the method of least squares is deployed to estimate the vector model parameters after transforming the complex vector regression model into a real vector regression model through isomorphism. Various operational statistics for testing the predictive significance of the estimated vector parameter coefficients are also derived. A simple numerical example demonstrates the use of the proposed vector regression analysis in modeling typhoon paths.

The effectiveness of reducing the daily dose of finasteride in men with benign prostatic hyperplasia

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Geller Jack

2002-01-01

Full Text Available Abstract Background Finasteride, a 5 alpha reductase inhibitor, is an established treatment for benign prostatic hyperplasia. The recommended dosage is 5 mg a day, however case reports have show effectiveness with lower doses. The objective of the current study was to determine in men with benign prostatic hyperplasia, previously treated for at least one year with finasteride 5 mg daily, if they will maintain subjective and objective improvements in urinary obstruction when treated with 2.5 mg of finasteride daily for one year. Methods In an open label, prospective study, 40 men with benign prostatic hyperplasia, previously treated for at least one year with 5 mg of finasteride, took 2.5 mg of finasteride daily for one year. Measurements included AUA symptom score, maximum flow rate, voided volume and PSA. Results There were no significant changes in maximum flow rate, voided volume, or AUA symptom score after one year of finasteride 2.5 mg daily therapy. PSA increased significantly, p Conclusions The daily dose of finasteride can be reduced to 2.5 mg daily without significant effect on subjective and objective measures of urinary obstruction. Although statistically significant increases in PSA are noted when reducing the daily finasteride dose from 5 mg to 2.5 mg, the clinical significance of a mean .6 ng/ml increase in PSA is questionable.

Adenovirus-Vectored Vaccine as a Rapid-Response Tool Against Avian Influenza Pandemic

International Nuclear Information System (INIS)

Van Kampen, K. R.; Tang, D. C.

2007-01-01

Influenza viruses in nature undergo genetic mutation and reassortment. Three pandemics of avian influenza in man were recorded in the twentieth century. Highly pathogenic avian influenza (HPAI) viruses currently in circulation pose a threat for another world-wide pandemic, if they become transmissible from man to man. Manufacturing protective vaccines using current egg-based technology is often difficult due to the virulence of the virus and its adverse effects on the embryonating egg substrate. New technologies allow the creation of safe and protective pandemic influenza vaccines without the need for egg based substrates. These technologies allow new vaccines to be created in less than one month. Manufacturing is in tissue culture, not eggs. Vaccine can be administered to man non-invasively, without adjuvants, eliciting a rapid and protective immune response. Protective immunity against avian influenza (AI) virus was elicited in chickens by single-dose in ovo vaccination with a replication-competent adenovirus (RCA)-free human adenovirus serotype 5 (Ad5)-derived vector encoding an H5N9 avian influenza virus hemagglutinin. Vaccinated chickens were protected against both H5N1 and H5N2 HPAI virus challenges. Mass-administration of this bird flu vaccine can be streamlined with available robotic in ovo injectors. Vaccination using this vaccine could protect the the largest host reservoir (chickens) and greatly reduce the exposure of man to avian influenza. In addition, Ad5-vectored vaccines can be produced rapidly and the safety margin of a non-replicating vector is superior to that of a replicating counterpart. Furthermore, this mode of vaccination is compatible with epidemiological surveys of natural AI virus infections. In addition to mass immunization of poultry, both animals and humans have been effectively immunized by intranasal administration of Ad5-vectored influenza vaccines without any appreciable side effects, even in mice and human volunteers with

Microneedle-mediated immunization of an adenovirus-based malaria vaccine enhances antigen-specific antibody immunity and reduces anti-vector responses compared to the intradermal route.

Science.gov (United States)

Carey, John B; Vrdoljak, Anto; O'Mahony, Conor; Hill, Adrian V S; Draper, Simon J; Moore, Anne C

2014-08-21

Substantial effort has been placed in developing efficacious recombinant attenuated adenovirus-based vaccines. However induction of immunity to the vector is a significant obstacle to its repeated use. Here we demonstrate that skin-based delivery of an adenovirus-based malaria vaccine, HAdV5-PyMSP1₄₂, to mice using silicon microneedles induces equivalent or enhanced antibody responses to the encoded antigen, however it results in decreased anti-vector responses, compared to intradermal delivery. Microneedle-mediated vaccine priming and resultant induction of low anti-vector antibody titres permitted repeated use of the same adenovirus vaccine vector. This resulted in significantly increased antigen-specific antibody responses in these mice compared to ID-treated mice. Boosting with a heterologous vaccine; MVA-PyMSP1₄₂ also resulted in significantly greater antibody responses in mice primed with HAdV5-PyMSP1₄₂ using MN compared to the ID route. The highest protection against blood-stage malaria challenge was observed when a heterologous route of immunization (MN/ID) was used. Therefore, microneedle-mediated immunization has potential to both overcome some of the logistic obstacles surrounding needle-and-syringe-based immunization as well as to facilitate the repeated use of the same adenovirus vaccine thereby potentially reducing manufacturing costs of multiple vaccines. This could have important benefits in the clinical ease of use of adenovirus-based immunization strategies.

Microneedle-mediated immunization of an adenovirus-based malaria vaccine enhances antigen-specific antibody immunity and reduces anti-vector responses compared to the intradermal route

Science.gov (United States)

Carey, John B.; Vrdoljak, Anto; O'Mahony, Conor; Hill, Adrian V. S.; Draper, Simon J.; Moore, Anne C.

2014-01-01

Substantial effort has been placed in developing efficacious recombinant attenuated adenovirus-based vaccines. However induction of immunity to the vector is a significant obstacle to its repeated use. Here we demonstrate that skin-based delivery of an adenovirus-based malaria vaccine, HAdV5-PyMSP142, to mice using silicon microneedles induces equivalent or enhanced antibody responses to the encoded antigen, however it results in decreased anti-vector responses, compared to intradermal delivery. Microneedle-mediated vaccine priming and resultant induction of low anti-vector antibody titres permitted repeated use of the same adenovirus vaccine vector. This resulted in significantly increased antigen-specific antibody responses in these mice compared to ID-treated mice. Boosting with a heterologous vaccine; MVA-PyMSP142 also resulted in significantly greater antibody responses in mice primed with HAdV5-PyMSP142 using MN compared to the ID route. The highest protection against blood-stage malaria challenge was observed when a heterologous route of immunization (MN/ID) was used. Therefore, microneedle-mediated immunization has potential to both overcome some of the logistic obstacles surrounding needle-and-syringe-based immunization as well as to facilitate the repeated use of the same adenovirus vaccine thereby potentially reducing manufacturing costs of multiple vaccines. This could have important benefits in the clinical ease of use of adenovirus-based immunization strategies. PMID:25142082

Potent and reversible lentiviral vector restriction in murine induced pluripotent stem cells.

Science.gov (United States)

Geis, Franziska K; Galla, Melanie; Hoffmann, Dirk; Kuehle, Johannes; Zychlinski, Daniela; Maetzig, Tobias; Schott, Juliane W; Schwarzer, Adrian; Goffinet, Christine; Goff, Stephen P; Schambach, Axel

2017-05-31

Retroviral vectors are derived from wild-type retroviruses, can be used to study retrovirus-host interactions and are effective tools in gene and cell therapy. However, numerous cell types are resistant or less permissive to retrovirus infection due to the presence of active defense mechanisms, or the absence of important cellular host co-factors. In contrast to multipotent stem cells, pluripotent stem cells (PSC) have potential to differentiate into all three germ layers. Much remains to be elucidated in the field of anti-viral immunity in stem cells, especially in PSC. In this study, we report that transduction with HIV-1-based, lentiviral vectors (LV) is impaired in murine PSC. Analyses of early retroviral events in induced pluripotent stem cells (iPSC) revealed that the restriction is independent of envelope choice and does not affect reverse transcription, but perturbs nuclear entry and proviral integration. Proteasomal inhibition by MG132 could not circumvent the restriction. However, prevention of cyclophilin A (CypA) binding to the HIV-1 capsid via use of either a CypA inhibitor (cyclosporine A) or CypA-independent capsid mutants improved transduction. In addition, application of higher vector doses also increased transduction. Our data revealed a CypA mediated restriction in iPSC, which was acquired during reprogramming, associated with pluripotency and relieved upon subsequent differentiation. We showed that murine PSC and iPSC are less susceptible to LV. The block observed in iPSC was CypA-dependent and resulted in reduced nuclear entry of viral DNA and proviral integration. Our study helps to improve transduction of murine pluripotent cells with HIV-1-based vectors and contributes to our understanding of retrovirus-host interactions in PSC.

Reduced-Nicotine Cigarettes in Young Smokers: Impact of Nicotine Metabolism on Nicotine Dose Effects.

Science.gov (United States)

Faulkner, Paul; Ghahremani, Dara G; Tyndale, Rachel F; Cox, Chelsea M; Kazanjian, Ari S; Paterson, Neil; Lotfipour, Shahrdad; Hellemann, Gerhard S; Petersen, Nicole; Vigil, Celia; London, Edythe D

2017-07-01

The use of cigarettes delivering different nicotine doses allows evaluation of the contribution of nicotine to the smoking experience. We compared responses of 46 young adult smokers to research cigarettes, delivering 0.027, 0.110, 0.231, or 0.763 mg nicotine, and conventional cigarettes. On five separate days, craving, withdrawal, affect, and sustained attention were measured after overnight abstinence and again after smoking. Participants also rated each cigarette, and the nicotine metabolite ratio (NMR) was used to identify participants as normal or slow metabolizers. All cigarettes equally alleviated craving, withdrawal, and negative affect in the whole sample, but normal metabolizers reported greater reductions of craving and withdrawal than slow metabolizers, with dose-dependent effects. Only conventional cigarettes and, to a lesser degree, 0.763-mg nicotine research cigarettes increased sustained attention. Finally, there were no differences between ratings of lower-dose cigarettes, but the 0.763-mg cigarettes and (even more so) conventional cigarettes were rated more favorably than lower-dose cigarettes. The findings indicate that smoking-induced relief of craving and withdrawal reflects primarily non-nicotine effects in slow metabolizers, but depends on nicotine dose in normal metabolizers. By contrast, relief of withdrawal-related attentional deficits and cigarette ratings depend on nicotine dose regardless of metabolizer status. These findings have bearing on the use of reduced-nicotine cigarettes to facilitate smoking cessation and on policy regarding regulation of nicotine content in cigarettes. They suggest that normal and slow nicotine metabolizers would respond differently to nicotine reduction in cigarettes, but that irrespective of metabolizer status, reductions to <0.763 mg/cigarette may contribute to temporary attentional deficits.

PA positioning significantly reduces testicular dose during sacroiliac joint radiography

International Nuclear Information System (INIS)

Mekis, Nejc; Mc Entee, Mark F.; Stegnar, Peter

2010-01-01

Radiation dose to the testes in the antero-posterior (AP) and postero-anterior (PA) projection of the sacroiliac joint (SIJ) was measured with and without a scrotal shield. Entrance surface dose, the dose received by the testicles and the dose area product (DAP) was used. DAP measurements revealed the dose received by the phantom in the PA position is 12.6% lower than the AP (p ≤ 0.009) with no statistically significant reduction in image quality (p ≤ 0.483). The dose received by the testes in the PA projection in SIJ imaging is 93.1% lower than the AP projection when not using protection (p ≤ 0.020) and 94.9% lower with protection (p ≤ 0.019). The dose received by the testicles was not changed by the use of a scrotal shield in the AP position (p ≤ 0.559); but was lowered by its use in the PA (p ≤ 0.058). Use of the PA projection in SIJ imaging significantly lowers, the dose received by the testes compared to the AP projection without significant loss of image quality.

Zoonotic aspects of vector-borne infections.

Science.gov (United States)

Failloux, A-B; Moutailler, S

2015-04-01

Vector-borne diseases are principally zoonotic diseases transmitted to humans by animals. Pathogens such as bacteria, parasites and viruses are primarily maintained within an enzootic cycle between populations of non-human primates or other mammals and largely non-anthropophilic vectors. This 'wild' cycle sometimes spills over in the form of occasional infections of humans and domestic animals. Lifestyle changes, incursions by humans into natural habitats and changes in agropastoral practices create opportunities that make the borders between wildlife and humans more permeable. Some vector-borne diseases have dispensed with the need for amplification in wild or domestic animals and they can now be directly transmitted to humans. This applies to some viruses (dengue and chikungunya) that have caused major epidemics. Bacteria of the genus Bartonella have reduced their transmission cycle to the minimum, with humans acting as reservoir, amplifier and disseminator. The design of control strategies for vector-borne diseases should be guided by research into emergence mechanisms in order to understand how a wild cycle can produce a pathogen that goes on to cause devastating urban epidemics.

Kochen-Specker vectors

International Nuclear Information System (INIS)

Pavicic, Mladen; Merlet, Jean-Pierre; McKay, Brendan; Megill, Norman D

2005-01-01

We give a constructive and exhaustive definition of Kochen-Specker (KS) vectors in a Hilbert space of any dimension as well as of all the remaining vectors of the space. KS vectors are elements of any set of orthonormal states, i.e., vectors in an n-dimensional Hilbert space, H n , n≥3, to which it is impossible to assign 1s and 0s in such a way that no two mutually orthogonal vectors from the set are both assigned 1 and that not all mutually orthogonal vectors are assigned 0. Our constructive definition of such KS vectors is based on algorithms that generate MMP diagrams corresponding to blocks of orthogonal vectors in R n , on algorithms that single out those diagrams on which algebraic (0)-(1) states cannot be defined, and on algorithms that solve nonlinear equations describing the orthogonalities of the vectors by means of statistically polynomially complex interval analysis and self-teaching programs. The algorithms are limited neither by the number of dimensions nor by the number of vectors. To demonstrate the power of the algorithms, all four-dimensional KS vector systems containing up to 24 vectors were generated and described, all three-dimensional vector systems containing up to 30 vectors were scanned, and several general properties of KS vectors were found

Can antibodies against flies alter malaria transmission in birds by changing vector behavior?

Science.gov (United States)

Ghosh, Suma; Waite, Jessica L; Clayton, Dale H; Adler, Frederick R

2014-10-07

Transmission of insect-borne diseases is shaped by the interactions among parasites, vectors, and hosts. Any factor that alters movement of infected vectors from infected to uninfeced hosts will in turn alter pathogen spread. In this paper, we study one such pathogen-vector-host system, avian malaria in pigeons transmitted by fly ectoparasites, where both two-way and three-way interactions play a key role in shaping disease spread. Bird immune defenses against flies can decrease malaria prevalence by reducing fly residence time on infected birds or increase disease prevalence by enhancing fly movement and thus infection transmission. We develop a mathematical model that illustrates how these changes in vector behavior influence pathogen transmission and show that malaria prevalence is maximized at an intermediate level of defense avoidance by the flies. Understanding how host immune defenses indirectly alter disease transmission by influencing vector behavior has implications for reducing the transmission of human malaria and other vectored pathogens. Published by Elsevier Ltd.

A comprehensive study on decreasing the kilovoltage cone-beam CT dose by reducing the projection number.

Science.gov (United States)

Lu, Bo; Lu, Haibin; Palta, Jatinder

2010-05-12

The objective of this study was to evaluate the effect of kilovoltage cone-beam computed tomography (CBCT) on registration accuracy and image qualities with a reduced number of planar projections used in volumetric imaging reconstruction. The ultimate goal is to evaluate the possibility of reducing the patient dose while maintaining registration accuracy under different projection-number schemes for various clinical sites. An Elekta Synergy Linear accelerator with an onboard CBCT system was used in this study. The quality of the Elekta XVI cone-beam three-dimensional volumetric images reconstructed with a decreasing number of projections was quantitatively evaluated by a Catphan phantom. Subsequently, we tested the registration accuracy of imaging data sets on three rigid anthropomorphic phantoms and three real patient sites under the reduced projection-number (as low as 1/6th) reconstruction of CBCT data with different rectilinear shifts and rota-tions. CBCT scan results of the Catphan phantom indicated the CBCT images got noisier when the number of projections was reduced, but their spatial resolution and uniformity were hardly affected. The maximum registration errors under the small amount transformation of the reference CT images were found to be within 0.7 mm translation and 0.3 masculine rotation. However, when the projection number was lower than one-fourth of the full set with a large amount of transformation of reference CT images, the registration could easily be trapped into local minima solutions for a nonrigid anatomy. We concluded, by using projection-number reduction strategy under conscientious care, imaging-guided localization procedure could achieve a lower patient dose without losing the registration accuracy for various clinical sites and situations. A faster scanning time is the main advantage compared to the mA decrease-based, dose-reduction method.

Elementary vectors

CERN Document Server

Wolstenholme, E Œ

1978-01-01

Elementary Vectors, Third Edition serves as an introductory course in vector analysis and is intended to present the theoretical and application aspects of vectors. The book covers topics that rigorously explain and provide definitions, principles, equations, and methods in vector analysis. Applications of vector methods to simple kinematical and dynamical problems; central forces and orbits; and solutions to geometrical problems are discussed as well. This edition of the text also provides an appendix, intended for students, which the author hopes to bridge the gap between theory and appl

A phantom study on fetal dose reducing factors in pregnant patients with breast cancer during radiotherapy treatment

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Akın Ogretici

2017-01-01

Full Text Available Purpose: This study aims to investigate the factors that reduce fetal dose in pregnant patients with breast cancer throughout their radiation treatment. Two main factors in a standard radiation oncology center are considered as the treatment planning systems (TPSs and simple shielding for intensity modulated radiation therapy technique. Materials and Methods: TPS factor was evaluated with two different planning algorithms: Anisotropic analytical algorithm and Acuros XB (external beam. To evaluate the shielding factor, a standard radiological purpose lead apron was chosen. For both studies, thermoluminescence dosimeters were used to measure the point dose, and an Alderson RANDO-phantom was used to simulate a female pregnant patient in this study. Thirteen measurement points were chosen in the 32nd slice of the phantom to cover all possible locations of a fetus up to 8th week of gestation. Results: The results show that both of the TPS algorithms are incapable of calculating the fetal doses, therefore, unable to reduce them at the planning stage. Shielding with a standard lead apron, however, showed a slight radiation protection (about 4.7% to the fetus decreasing the mean fetal dose from 84.8 mGy to 80.8 mGy, which cannot be disregarded in case of fetal irradiation. Conclusions: Using a lead apron for shielding the abdominal region of a pregnant patient during breast irradiation showed a minor advantage; however, its possible side effects (i.e., increased scattered radiation and skin dose should also be investigated further to solidify its benefits.

Automatic spectral imaging protocol selection and iterative reconstruction in abdominal CT with reduced contrast agent dose: initial experience.

Science.gov (United States)

Lv, Peijie; Liu, Jie; Chai, Yaru; Yan, Xiaopeng; Gao, Jianbo; Dong, Junqiang

2017-01-01

To evaluate the feasibility, image quality, and radiation dose of automatic spectral imaging protocol selection (ASIS) and adaptive statistical iterative reconstruction (ASIR) with reduced contrast agent dose in abdominal multiphase CT. One hundred and sixty patients were randomly divided into two scan protocols (n = 80 each; protocol A, 120 kVp/450 mgI/kg, filtered back projection algorithm (FBP); protocol B, spectral CT imaging with ASIS and 40 to 70 keV monochromatic images generated per 300 mgI/kg, ASIR algorithm. Quantitative parameters (image noise and contrast-to-noise ratios [CNRs]) and qualitative visual parameters (image noise, small structures, organ enhancement, and overall image quality) were compared. Monochromatic images at 50 keV and 60 keV provided similar or lower image noise, but higher contrast and overall image quality as compared with 120-kVp images. Despite the higher image noise, 40-keV images showed similar overall image quality compared to 120-kVp images. Radiation dose did not differ between the two protocols, while contrast agent dose in protocol B was reduced by 33 %. Application of ASIR and ASIS to monochromatic imaging from 40 to 60 keV allowed contrast agent dose reduction with adequate image quality and without increasing radiation dose compared to 120 kVp with FBP. • Automatic spectral imaging protocol selection provides appropriate scan protocols. • Abdominal CT is feasible using spectral imaging and 300 mgI/kg contrast agent. • 50-keV monochromatic images with 50 % ASIR provide optimal image quality.

The Insect Microbiome Modulates Vector Competence for Arboviruses

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Natapong Jupatanakul

2014-11-01

Full Text Available Diseases caused by arthropod-borne viruses (arboviruses, such as Dengue, West Nile, and Chikungunya, constitute a major global health burden and are increasing in incidence and geographic range. The natural microbiota of insect vectors influences various aspects of host biology, such as nutrition, reproduction, metabolism, and immunity, and recent studies have highlighted the ability of insect-associated bacteria to reduce vector competence for arboviruses and other pathogens. This reduction can occur through mechanisms, such as immune response activation, resource competition, or the production of anti-viral molecules. Studying the interactions between insect vectors and their microbiota is an important step toward developing alternative strategies for arbovirus transmission control.

Efficacy of reduced doses of bentazone assessed by instruments based on measurement of chlorophyll fluorescence

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Vojtěch Kocurek

2011-01-01

Full Text Available Chlorophyll fluorescence is a type of radiation emitted by plants as unused part of energy absorbed from sunlight. Its intensity depends on many stress factors, nutrition, weather conditions etc. Methods based on chlorophyll fluorescence measurement have potential to be perspective for the assessment of herbicide efficacy, phytotoxicity or stress influence. Two fluorometers (FluorCam and handy FluorPen were used for measurements in laboratory experiments in 2007–2009. Herbicide Basagran super with active ingredient bentazone (480 g.l−1 was tested using a parameter called ‚Quantum yield of fluorescence‘ (QY in three different doses: the registered dose 2.0 l.ha−1 (100% and lower doses 1.5 l.ha−1 (75% and 1.0 l.ha−1 (50%. Treated experimental plants of redroot pigweed (Amaranthus retroflexus L. were measured in 0, 1, 2, 3, 6, 9 and 15 days after treatment and the results were compared with subjective assessment (estimation and growth parameters. The obtained results showed that the effect of bentazone measured by both devices was statistically significantly different from untreated control. We can also detect herbicide effect earlier by QY measurement than by other methods. Different doses showed significant differences 15 days after treatment for dose 2.0 l.ha−1 in comparison with both reduced doses. The subjective assessment showed significant differences in all terms of measurement (1–15 days after application except of the day of application. Regeneration of plants for which the youngest leaves were not treated by herbicide was observed for all doses. Difference of QY values between used devices was on average 0.119 (higher for FluorCam but statistically insignificant.

Resolution of Mild Ganciclovir-Resistant Cytomegalovirus Disease with Reduced-Dose Cidofovir and CMV-Hyperimmune Globulin.

Science.gov (United States)

Patel, Samir J; Kuten, Samantha A; Knight, Richard J; Hong, Dana M; Gaber, A Osama

2014-01-01

Ganciclovir-resistant cytomegalovirus (CMV) is associated with significant morbidity in solid organ transplant recipients. Management of ganciclovir-resistant CMV may be complicated by nephrotoxicity which is commonly observed with recommended therapies and/or rejection induced by "indirect" viral effects or reduction of immunosuppression. Herein, we report a series of four high serologic risk (donor CMV positive/recipient CMV negative) kidney transplant patients diagnosed with ganciclovir-resistant CMV disease. All patients initially developed "breakthrough" viremia while still receiving valganciclovir prophylaxis after transplant and were later confirmed to exhibit UL97 mutations after failing to eradicate virus on adequate dosages of valganciclovir. The patients were subsequently and successfully treated with reduced-dose (1-2 mg/kg) cidofovir and CMV-hyperimmune globulin, given in 2-week intervals. In addition, all patients exhibited stable renal function after completion of therapy, and none experienced acute rejection. The combination of reduced-dose cidofovir and CMV-hyperimmune globulin appeared to be a safe and effective regimen in patients with mild disease due to ganciclovir-resistant CMV.

Evaluation of Pyrethrin Formulations on Dengue/Dengue Haemorrhagic Fever Vectors in the Laboratory and Sublethal Effects

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S Sulaiman

2007-12-01

Full Text Available In Southeast Asia, Aedes aegypti (L. has been incriminated as principal vector of dengue viruses and Ae. albopictus as the secondary vector of dengue fever. Therefore, the aim of this study was to investigate the effectiveness of three for-mula¬tions of pyrethrin derived from Tanacetum cinerariaefolium against the dengue/dengue haemorrhagic fever vectors Aedes aegypti and Ae. albopictus in the laboratory. The testings employed 2 methodologies: the WHO Larval Bioassay and WHO Adult Bioassay. The results showed that all the three pyrethrin formulations had larvicidal and adulticidal activi-ties. The impact of the sublethal doses of pyrethrin formulations on Aedes spp. larvae resulted in 4-6% of alive adult emergence compared to 90% of Ae. aegypti emerging adults and 96% Ae. albopictus alive adult emergence in the control. The impact of sublethal doses of the pyrethrin formulations caused very low fecundity on both Aedes spp. compared to the control (P< 0.05.

Evaluation of Pyrethrin Formulations on Dengue/Dengue Haemorrhagic Fever Vectors in the Laboratory and Sublethal Effects

Directory of Open Access Journals (Sweden)

S Sulaiman

2007-11-01

Full Text Available In Southeast Asia, Aedes aegypti (L. has been incriminated as principal vector of dengue viruses and Ae. albopictus as the secondary vector of dengue fever. Therefore, the aim of this study was to investigate the effectiveness of three for-mula¬tions of pyrethrin derived from Tanacetum cinerariaefolium against the dengue/dengue haemorrhagic fever vectors Aedes aegypti and Ae. albopictus in the laboratory. The testings employed 2 methodologies: the WHO Larval Bioassay and WHO Adult Bioassay. The results showed that all the three pyrethrin formulations had larvicidal and adulticidal activi-ties. The impact of the sublethal doses of pyrethrin formulations on Aedes spp. larvae resulted in 4-6% of alive adult emergence compared to 90% of Ae. aegypti emerging adults and 96% Ae. albopictus alive adult emergence in the control. The impact of sublethal doses of the pyrethrin formulations caused very low fecundity on both Aedes spp. compared to the control (P< 0.05.

Use of adenoviral vectors as veterinary vaccines.

Science.gov (United States)

Ferreira, T B; Alves, P M; Aunins, J G; Carrondo, M J T

2005-10-01

Vaccines are the most effective and inexpensive prophylactic tool in veterinary medicine. Ideally, vaccines should induce a lifelong protective immunity against the target pathogen while not causing clinical or pathological signs of diseases in the vaccinated animals. However, such ideal vaccines are rare in the veterinary field. Many vaccines are either of limited effectiveness or have harmful side effects. In addition, there are still severe diseases with no effective vaccines. A very important criterion for an ideal vaccine in veterinary medicine is low cost; this is especially important in developing countries and even more so for poultry vaccination, where vaccines must sell for a few cents a dose. Traditional approaches include inactivated vaccines, attenuated live vaccines and subunit vaccines. Recently, genetic engineering has been applied to design new, improved vaccines. Adenovirus vectors are highly efficient for gene transfer in a broad spectrum of cell types and species. Moreover, adenoviruses often induce humoral, mucosal and cellular immune responses to antigens encoded by the inserted foreign genes. Thus, adenoviruses have become a vector of choice for delivery and expression of foreign proteins for vaccination. Consequently, the market requirements for adenovirus vaccines are increasing, creating a need for production methodologies of concentrated vectors with warranted purity and efficacy. This review summarizes recent developments and approaches of adenovirus production and purification as the application of these vectors, including successes and failures in clinical applications to date.

Short-Term Therapy with High Dose Atorvastatin in Patients with Coronary Artery Disease Can Reduce Inflammatory Process

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Vida Nesar Hossein

2010-08-01

Full Text Available Coronary heart disease is the leading cause of death and disability in adults. The association between acute coronary syndrom (ACS and elevated serum high sensitivity c-reactive protein (hsCRP suggests that chronic inflammation of the coronary arterial wall may play an important role. A number of drugs used in the treatment of cardiovascular disease reduce serum CRP. It* is therefore possible that reduced inflammation contributes to the beneficial effects of these medications. This was a double blind randomized clinical trial on 52 patients were admitted because of ACS at the Mazandaran Heart Center, Iran in 2007. The patients were divided to three randomized groups which received 20, 40, 80* mg Atorvastatin daily for 6 months. At the time of study enrollment and 1, 3 and 6 months after initiation hsCRP were measured. 1 and 3 month after 20mg atorvastatin therapy the median serum concentration of hsCRP did not decrease significantly, but at the end of 6th month it was* significant difference. At 40mg dosage from 3th month to 6th month versus 1st month to 3th month it was significant decrease, at the end of 1th month and 3rd month it was not significant. At 80mg dose at the end of 1th month it was not significant but at the* end of 3th month and end of 6th month it was significant. Intensive lipid-lowering therapy with high-dose atorvastatin therapy relative to moderate lipid-lowering therapy with low-dose atorvastatin reduces hsCRP better. We found that treatment with greater dose of atorvastatin might decrease greater in plasma level of hsCRP.

Interpolation of vector fields from human cardiac DT-MRI

International Nuclear Information System (INIS)

Yang, F; Zhu, Y M; Rapacchi, S; Robini, M; Croisille, P; Luo, J H

2011-01-01

There has recently been increased interest in developing tensor data processing methods for the new medical imaging modality referred to as diffusion tensor magnetic resonance imaging (DT-MRI). This paper proposes a method for interpolating the primary vector fields from human cardiac DT-MRI, with the particularity of achieving interpolation and denoising simultaneously. The method consists of localizing the noise-corrupted vectors using the local statistical properties of vector fields, removing the noise-corrupted vectors and reconstructing them by using the thin plate spline (TPS) model, and finally applying global TPS interpolation to increase the resolution in the spatial domain. Experiments on 17 human hearts show that the proposed method allows us to obtain higher resolution while reducing noise, preserving details and improving direction coherence (DC) of vector fields as well as fiber tracking. Moreover, the proposed method perfectly reconstructs azimuth and elevation angle maps.

Research on intrusion detection based on Kohonen network and support vector machine

Science.gov (United States)

Shuai, Chunyan; Yang, Hengcheng; Gong, Zeweiyi

2018-05-01

In view of the problem of low detection accuracy and the long detection time of support vector machine, which directly applied to the network intrusion detection system. Optimization of SVM parameters can greatly improve the detection accuracy, but it can not be applied to high-speed network because of the long detection time. a method based on Kohonen neural network feature selection is proposed to reduce the optimization time of support vector machine parameters. Firstly, this paper is to calculate the weights of the KDD99 network intrusion data by Kohonen network and select feature by weight. Then, after the feature selection is completed, genetic algorithm (GA) and grid search method are used for parameter optimization to find the appropriate parameters and classify them by support vector machines. By comparing experiments, it is concluded that feature selection can reduce the time of parameter optimization, which has little influence on the accuracy of classification. The experiments suggest that the support vector machine can be used in the network intrusion detection system and reduce the missing rate.

Reduced herbicide doses in combination with allelopathic plant extracts suppress weeds in wheat

International Nuclear Information System (INIS)

Afridi, R.A.; Khan, M.A.

2014-01-01

Allelopathy is gaining popularity worldwide probably for decreasing the cost of production and environment friendly weed suppressing approach. Repeated field studies conducted during 2011-12 and 2012-13 at Agricutural Research Institute Tarnab, Peshawar, Pakistan where allelopathic water extracts of Oryza sativa, Parthenium hysterophorus, Phragmites australis and Datura alba along with reduced doses of phenoxaprop-p-ethyl and bromoxinil+MCPA were tested for controlling weeds in wheat. It was observed that weed density was encouragly suppressed whereas spike length (cm), number of spikelets spike-1 and 1000 grain weight (g) of the wheat were improved when the allelopathic plant water extracts were used in combination with lower doses of herbicides. Thus, allelochemicals provide weed suppressing option in wheat. However, more studies are required to fully explore the possibility of weed management and isolation of the chemicals involved in weed suppression for environment friendly weed management in wheat. Such studies may decrease the cost of crop production and total use of herbicides. (author)

Adenovirus Vector-Derived VA-RNA-Mediated Innate Immune Responses

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Hiroyuki Mizuguchi

2011-07-01

Full Text Available The major limitation of the clinical use of replication-incompetent adenovirus (Ad vectors is the interference by innate immune responses, including induction of inflammatory cytokines and interferons (IFN, following in vivo application of Ad vectors. Ad vector-induced production of inflammatory cytokines and IFNs also results in severe organ damage and efficient induction of acquired immune responses against Ad proteins and transgene products. Ad vector-induced innate immune responses are triggered by the recognition of Ad components by pattern recognition receptors (PRRs. In order to reduce the side effects by Ad vector-induced innate immune responses and to develop safer Ad vectors, it is crucial to clarify which PRRs and which Ad components are involved in Ad vector-induced innate immune responses. Our group previously demonstrated that myeloid differentiating factor 88 (MyD88 and toll-like receptor 9 (TLR9 play crucial roles in the Ad vector-induced inflammatory cytokine production in mouse bone marrow-derived dendritic cells. Furthermore, our group recently found that virus associated-RNAs (VA-RNAs, which are about 160 nucleotide-long non-coding small RNAs encoded in the Ad genome, are involved in IFN production through the IFN-β promoter stimulator-1 (IPS-1-mediated signaling pathway following Ad vector transduction. The aim of this review is to highlight the Ad vector-induced innate immune responses following transduction, especially VA-RNA-mediated innate immune responses. Our findings on the mechanism of Ad vector-induced innate immune responses should make an important contribution to the development of safer Ad vectors, such as an Ad vector lacking expression of VA-RNAs.

Attenuation of Replication-Competent Adenovirus Serotype 26 Vaccines by Vectorization.

Science.gov (United States)

Maxfield, Lori F; Abbink, Peter; Stephenson, Kathryn E; Borducchi, Erica N; Ng'ang'a, David; Kirilova, Marinela M; Paulino, Noelix; Boyd, Michael; Shabram, Paul; Ruan, Qian; Patel, Mayank; Barouch, Dan H

2015-11-01

Replication-competent adenovirus (rcAd)-based vaccine vectors may theoretically provide immunological advantages over replication-incompetent Ad vectors, but they also raise additional potential clinical and regulatory issues. We produced replication-competent Ad serotype 26 (rcAd26) vectors by adding the E1 region back into a replication-incompetent Ad26 vector backbone with the E3 or E3/E4 regions deleted. We assessed the effect of vectorization on the replicative capacity of the rcAd26 vaccines. Attenuation occurred in a stepwise fashion, with E3 deletion, E4 deletion, and human immunodeficiency virus type 1 (HIV-1) envelope (Env) gene insertion all contributing to reduced replicative capacity compared to that with the wild-type Ad26 vector. The rcAd26 vector with E3 and E4 deleted and containing the Env transgene exhibited 2.7- to 4.4-log-lower replicative capacity than that of the wild-type Ad26 in vitro. This rcAd26 vector is currently being evaluated in a phase 1 clinical trial. Attenuation as a result of vectorization and transgene insertion has implications for the clinical development of replication-competent vaccine vectors. Copyright © 2015, Maxfield et al.

Genetic manipulation of endosymbionts to control vector and vector borne diseases

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Jay Prakash Gupta

Full Text Available Vector borne diseases (VBD are on the rise because of failure of the existing methods of control of vector and vector borne diseases and the climate change. A steep rise of VBDs are due to several factors like selection of insecticide resistant vector population, drug resistant parasite population and lack of effective vaccines against the VBDs. Environmental pollution, public health hazard and insecticide resistant vector population indicate that the insecticides are no longer a sustainable control method of vector and vector-borne diseases. Amongst the various alternative control strategies, symbiont based approach utilizing endosymbionts of arthropod vectors could be explored to control the vector and vector borne diseases. The endosymbiont population of arthropod vectors could be exploited in different ways viz., as a chemotherapeutic target, vaccine target for the control of vectors. Expression of molecules with antiparasitic activity by genetically transformed symbiotic bacteria of disease-transmitting arthropods may serve as a powerful approach to control certain arthropod-borne diseases. Genetic transformation of symbiotic bacteria of the arthropod vector to alter the vector’s ability to transmit pathogen is an alternative means of blocking the transmission of VBDs. In Indian scenario, where dengue, chikungunya, malaria and filariosis are prevalent, paratransgenic based approach can be used effectively. [Vet World 2012; 5(9.000: 571-576

Emerging vector borne diseases – incidence through vectors

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Sara eSavic

2014-12-01

Full Text Available Vector borne diseases use to be a major public health concern only in tropical and subtropical areas, but today they are an emerging threat for the continental and developed countries also. Nowdays, in intercontinetal countries, there is a struggle with emerging diseases which have found their way to appear through vectors. Vector borne zoonotic diseases occur when vectors, animal hosts, climate conditions, pathogens and susceptible human population exist at the same time, at the same place. Global climate change is predicted to lead to an increase in vector borne infectious diseases and disease outbreaks. It could affect the range and popultion of pathogens, host and vectors, transmission season, etc. Reliable surveilance for diseases that are most likely to emerge is required. Canine vector borne diseases represent a complex group of diseases including anaplasmosis, babesiosis, bartonellosis, borreliosis, dirofilariosis, erlichiosis, leishmaniosis. Some of these diseases cause serious clinical symptoms in dogs and some of them have a zoonotic potential with an effect to public health. It is expected from veterinarians in coordination with medical doctors to play a fudamental role at primeraly prevention and then treatment of vector borne diseases in dogs. The One Health concept has to be integrated into the struggle against emerging diseases.During a four year period, from 2009-2013, a total number of 551 dog samples were analysed for vector borne diseases (borreliosis, babesiosis, erlichiosis, anaplasmosis, dirofilariosis and leishmaniasis in routine laboratory work. The analysis were done by serological tests – ELISA for borreliosis, dirofilariosis and leishmaniasis, modified Knott test for dirofilariosis and blood smear for babesiosis, erlichiosis and anaplasmosis. This number of samples represented 75% of total number of samples that were sent for analysis for different diseases in dogs. Annually, on avarege more then half of the samples

Vaccination strategies for SIR vector-transmitted diseases.

Science.gov (United States)

Cruz-Pacheco, Gustavo; Esteva, Lourdes; Vargas, Cristobal

2014-08-01

Vector-borne diseases are one of the major public health problems in the world with the fastest spreading rate. Control measures have been focused on vector control, with poor results in most cases. Vaccines should help to reduce the diseases incidence, but vaccination strategies should also be defined. In this work, we propose a vector-transmitted SIR disease model with age-structured population subject to a vaccination program. We find an expression for the age-dependent basic reproductive number R(0), and we show that the disease-free equilibrium is locally stable for R(0) ≤ 1, and a unique endemic equilibrium exists for R(0) > 1. We apply the theoretical results to public data to evaluate vaccination strategies, immunization levels, and optimal age of vaccination for dengue disease.

Vector-vector production in photon-photon interactions

International Nuclear Information System (INIS)

Ronan, M.T.

1988-01-01

Measurements of exclusive untagged /rho/ 0 /rho/ 0 , /rho//phi/, K/sup *//bar K//sup */, and /rho/ω production and tagged /rho/ 0 /rho/ 0 production in photon-photon interactions by the TPC/Two-Gamma experiment are reviewed. Comparisons to the results of other experiments and to models of vector-vector production are made. Fits to the data following a four quark model prescription for vector meson pair production are also presented. 10 refs., 9 figs

Does fast-neutron radiotherapy merely reduce the radiation dose

International Nuclear Information System (INIS)

Ando, Koichi

1984-01-01

We examined whether fast-neutron radiotherapy is superior to low-LET radiotherpy by comparing the relationship between cell survival and tumor control probabilities after exposure of tumor-bearing (species) to the two modalities. Analysis based on TCD 50 assay and lung colony assay indicated that single dose of fast neutron achieved animal cures at higher survival rates than other radiation modalities including single and fractionated γ-ray doses, fractionated doses of fast neutron, and the mixed-beam scheme with a sequence of N-γ-γ-γ-N. We conclude that fast-neutron radiotherapy cured animal tumors with lower cell killing rates other radiation modalities. (author)

IMMUNE RESPONSES OF GOATS (SHAMI BREED TO VACCINATION WITH A FULL, REDUCED AND CONJUNCTIVAL DOSE OF BRUCEVAC (BRUCELLA MELITENSIS REV.1 VACCINE

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F. ALDOMY, M. ALKHAWALDEH1 AND I. B. YOUNIS

2009-10-01

Full Text Available Three groups of Shami goats were randomly vaccinated with Brucevac (Rev. 1 vaccine. Group 1 was vaccinated subcutaneously with a full dose (1.54 x 109 organisms. Group 2 was vaccinated conjunctively with one eye drop (5.2 x 108 organisms, while Group 3 was injected subcutaneously with a reduced dose (7.1 x 105 organisms of vaccine. Blood samples were collected before vaccination, two, four, eight, 15 and 24 weeks post vaccination. All samples were tested through CFT, ELISA, SAT and Rose Bengal plate test. All serological tests used detected a higher percentage of vaccinated female kids with a full dose than they did in other groups vaccinated with a reduced dose or with a conjunctival dose of Rev.1 vaccine. The overall results suggested that 100% of animals vaccinated with a conjunctival dose became positive to CFT at two, four, eight and 15 weeks post vaccination, and then the percentage of seropositive animals declined and became 20% at 24 weeks post inoculation. The conjunctival route of vaccination significantly reduced the intensity and duration of the post vaccination serological response, which makes the use of this vaccine compatible with brucellosis programmes, even when these are based on a test-and–slaughter policy. The overall results showed that Shami goats responded to Rev.1 vaccine in the expected way. The majority of animals were seropositive to the CFT by two weeks after vaccination with higher numbers of seropositive animals in the kids group vaccinated with a full dose of Rev.1 vaccine.

Head CT: Image quality improvement with ASIR-V using a reduced radiation dose protocol for children

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyun Gi [Ajou University School of Medicine, Ajou University Medical Center, Department of Radiology, Yeongtong-gu, Suwon (Korea, Republic of); Lee, Ho-Joon; Lee, Seung-Koo; Kim, Myung-Joon [Severance Hospital, Yonsei University College of Medicine, Department of Radiology and Research Institute of Radiological Science, Seodaemun-gu, Seoul (Korea, Republic of); Kim, Hyun Ji [Ajou University School of Medicine, Office of Biostatistics, Department of Humanities and Social Medicine, Yeongtong-gu, Suwon (Korea, Republic of)

2017-09-15

To investigate the quality of images reconstructed with adaptive statistical iterative reconstruction V (ASIR-V), using pediatric head CT protocols. A phantom was scanned at decreasing 20% mA intervals using our standard pediatric head CT protocols. Each study was then reconstructed at 10% ASIR-V intervals. After the phantom study, we reduced mA by 10% in the protocol for <3-year-old patients and applied 30% ASIR-V and by 30% in the protocol for 3- to 15-year-old patients and applied 40% ASIR-V. Increasing the percentage of ASIR-V resulted in lower noise and higher contrast-to-noise ratio (CNR) and preserved spatial resolution in the phantom study. Compared to a conventional-protocol, reduced-dose protocol with ASIR-V achieved 12.8% to 34.0% of dose reduction and showed images of lower noise (9.22 vs. 10.73, P = 0.043) and higher CNR in different levels (centrum semiovale, 2.14 vs. 1.52, P = 0.003; basal ganglia, 1.46 vs. 1.07, P = 0.001; and cerebellum, 2.18 vs. 1.33, P < 0.001). Qualitative analysis showed higher gray-white matter differentiation and sharpness and preserved overall diagnostic quality in the images with ASIR-V. Use of ASIR-V allowed a 12.8% to 34.0% dose reduction in each age group with potential to improve image quality. (orig.)

Head CT: Image quality improvement with ASIR-V using a reduced radiation dose protocol for children

International Nuclear Information System (INIS)

Kim, Hyun Gi; Lee, Ho-Joon; Lee, Seung-Koo; Kim, Myung-Joon; Kim, Hyun Ji

2017-01-01

To investigate the quality of images reconstructed with adaptive statistical iterative reconstruction V (ASIR-V), using pediatric head CT protocols. A phantom was scanned at decreasing 20% mA intervals using our standard pediatric head CT protocols. Each study was then reconstructed at 10% ASIR-V intervals. After the phantom study, we reduced mA by 10% in the protocol for <3-year-old patients and applied 30% ASIR-V and by 30% in the protocol for 3- to 15-year-old patients and applied 40% ASIR-V. Increasing the percentage of ASIR-V resulted in lower noise and higher contrast-to-noise ratio (CNR) and preserved spatial resolution in the phantom study. Compared to a conventional-protocol, reduced-dose protocol with ASIR-V achieved 12.8% to 34.0% of dose reduction and showed images of lower noise (9.22 vs. 10.73, P = 0.043) and higher CNR in different levels (centrum semiovale, 2.14 vs. 1.52, P = 0.003; basal ganglia, 1.46 vs. 1.07, P = 0.001; and cerebellum, 2.18 vs. 1.33, P < 0.001). Qualitative analysis showed higher gray-white matter differentiation and sharpness and preserved overall diagnostic quality in the images with ASIR-V. Use of ASIR-V allowed a 12.8% to 34.0% dose reduction in each age group with potential to improve image quality. (orig.)

Anopheles Vectors in Mainland China While Approaching Malaria Elimination.

Science.gov (United States)

Zhang, Shaosen; Guo, Shaohua; Feng, Xinyu; Afelt, Aneta; Frutos, Roger; Zhou, Shuisen; Manguin, Sylvie

2017-11-01

China is approaching malaria elimination; however, well-documented information on malaria vectors is still missing, which could hinder the development of appropriate surveillance strategies and WHO certification. This review summarizes the nationwide distribution of malaria vectors, their bionomic characteristics, control measures, and related studies. After several years of effort, the area of distribution of the principal malaria vectors was reduced, in particular for Anopheles lesteri (synonym: An. anthropophagus) and Anopheles dirus s.l., which nearly disappeared from their former endemic regions. Anopheles sinensis is becoming the predominant species in southwestern China. The bionomic characteristics of these species have changed, and resistance to insecticides was reported. There is a need to update surveillance tools and investigate the role of secondary vectors in malaria transmission. Copyright © 2017 Elsevier Ltd. All rights reserved.

The use of a compensator library to reduce dose inhomogeneity in tangential radiotherapy of the breast

International Nuclear Information System (INIS)

Wilks, Robin J.; Bliss, Peter

2002-01-01

Background and purpose: The dose variation throughout the volume of the breast from tangential fields can exceed 20% for large breasts. This is postulated to result in poor cosmesis [Radiother Oncol 16 (1989) 253], particularly at the inframammary fold, where the dose is highest. Compensators may be used to reduce this variation, but at the cost of the time to manufacture each unique compensator for the individual patients. This paper outlines the implementation and routine use of a library of reusable compensators. Materials and methods: For the period of December 1999 to May 2001, 94 patients attending for breast radiotherapy received treatment using breast compensators calculated from multiple outlines measured using the Osiris system. The compensators manufactured for the early patients were added to a library for possible reuse by later patients. Of the 94 patients, 28 patients' compensators formed the library and 66 subsequent patients have been treated using compensators derived from the library. Selection of the most appropriate library compensator was determined from the analysis of the distribution of the calculated dose-volume histogram for the whole breast, excluding lung, penumbra and build-up regions. Once the library was complete, approximately 50% of all subsequent breast patients were treated with compensators (46% from the library and 4% with individual compensators). This represented a usage rate of 92% for the library compensators for those patients requiring compensation. Results: In all cases the compensators reduced the variation in the dose distribution. For example, the group treated with a library compensator demonstrated a mean reduction from 29 to 9% for the volume of breast tissue receiving more than 5% greater than the reference dose. If the same patients had been treated using their own individual compensators, the corresponding value would have been 7%. There is a small systematic, but negligible, difference in the two populations of

A crisis management decision support system to reduce ingestion dose

International Nuclear Information System (INIS)

Schenker-Wicki, A.; Gibbert, R.

1993-01-01

Environmental accidents such as extensive radioactive or chemical contamination can have more serious consequences for a population than any other kind of accidents known before. Owing to the serious consequences and the high number of people who may be affected, the selection of the best countermeasures to ameliorate the imminent impact is very difficult and the political responsibility is enormous. To help overcome such problems the National Emergency Operations Center in Zurich (Switzerland) has developed a decision support system to evaluate acceptable countermeasures for reducing ingestion dose after an accidental release of radioactive material. The system involves all the necessary modules and techniques for efficient decision making, based on the most recent developments in decision theory as well as the necessary structuring of the decision-making process. The decision-making concept comprehends decision making on two different levels, a technical and a political one. (author)

Rare Hadronic B Decays to Vector, Axial-Vector and Tensors

International Nuclear Information System (INIS)

Gao, Y.Y.

2011-01-01

The authors review BABAR measurements of several rare B decays, including vector-axial-vector decays B ± → φK 1 ± (1270), B ± → φ K 1 ± (1400) and B ± → b 1 # -+ρ# ± , vector-vector decays B ± → φK* ± (1410), B 0 → K* 0 (bar K)* 0 , B 0 → K*0K*0 and B 0 → K*+K*-, vector-tensor decays B ± → φK* 2 (1430) ± and φK 2 (1770)/ ± (1820), and vector-scalar decays B ± → φK* 0 (1430) ± . Understanding the observed polarization pattern requires amplitude contributions from an uncertain source.

The PA projection of the clavicle: a dose-reducing technique.

LENUS (Irish Health Repository)

Mc Entee, Mark F

2010-06-01

This study compares dose and image quality during PA and AP radiography of the clavicle. The methodology involved a cadaver-based dose and image quality study. Results demonstrate a statistically significant 56.1 % (p dose with employment of PA and PA15 caudal projections. Reductions of 28.5 % (p doses to the eye were demonstrated for the PA. Differences in entrance-surface and exit doses were deemed non-significant. A 5.9 % (p dose reductions to the thyroid and breast when PA projection is chosen over the AP projection. The authors recommend the implementation of PA positioning for clavicle radiography.

Integrated vector management for malaria control

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Impoinvil Daniel E

2008-12-01

Full Text Available Abstract Integrated vector management (IVM is defined as "a rational decision-making process for the optimal use of resources for vector control" and includes five key elements: 1 evidence-based decision-making, 2 integrated approaches 3, collaboration within the health sector and with other sectors, 4 advocacy, social mobilization, and legislation, and 5 capacity-building. In 2004, the WHO adopted IVM globally for the control of all vector-borne diseases. Important recent progress has been made in developing and promoting IVM for national malaria control programmes in Africa at a time when successful malaria control programmes are scaling-up with insecticide-treated nets (ITN and/or indoor residual spraying (IRS coverage. While interventions using only ITNs and/or IRS successfully reduce transmission intensity and the burden of malaria in many situations, it is not clear if these interventions alone will achieve those critical low levels that result in malaria elimination. Despite the successful employment of comprehensive integrated malaria control programmes, further strengthening of vector control components through IVM is relevant, especially during the "end-game" where control is successful and further efforts are required to go from low transmission situations to sustained local and country-wide malaria elimination. To meet this need and to ensure sustainability of control efforts, malaria control programmes should strengthen their capacity to use data for decision-making with respect to evaluation of current vector control programmes, employment of additional vector control tools in conjunction with ITN/IRS tactics, case-detection and treatment strategies, and determine how much and what types of vector control and interdisciplinary input are required to achieve malaria elimination. Similarly, on a global scale, there is a need for continued research to identify and evaluate new tools for vector control that can be integrated with

Eilat virus displays a narrow mosquito vector range.

Science.gov (United States)

Nasar, Farooq; Haddow, Andrew D; Tesh, Robert B; Weaver, Scott C

2014-12-17

Most alphaviruses are arthropod-borne and utilize mosquitoes as vectors for transmission to susceptible vertebrate hosts. This ability to infect both mosquitoes and vertebrates is essential for maintenance of most alphaviruses in nature. A recently characterized alphavirus, Eilat virus (EILV), isolated from a pool of Anopheles coustani s.I. is unable to replicate in vertebrate cell lines. The EILV host range restriction occurs at both attachment/entry as well as genomic RNA replication levels. Here we investigated the mosquito vector range of EILV in species encompassing three genera that are responsible for maintenance of other alphaviruses in nature. Susceptibility studies were performed in four mosquito species: Aedes albopictus, A. aegypti, Anopheles gambiae, and Culex quinquefasciatus via intrathoracic and oral routes utilizing EILV and EILV expressing red fluorescent protein (-eRFP) clones. EILV-eRFP was injected at 10(7) PFU/mL to visualize replication in various mosquito organs at 7 days post-infection. Mosquitoes were also injected with EILV at 10(4)-10(1) PFU/mosquito and virus replication was measured via plaque assays at day 7 post-infection. Lastly, mosquitoes were provided bloodmeals containing EILV-eRFP at doses of 10(9), 10(7), 10(5) PFU/mL, and infection and dissemination rates were determined at 14 days post-infection. All four species were susceptible via the intrathoracic route; however, replication was 10-100 fold less than typical for most alphaviruses, and infection was limited to midgut-associated muscle tissue and salivary glands. A. albopictus was refractory to oral infection, while A. gambiae and C. quinquefasciatus were susceptible only at 10(9) PFU/mL dose. In contrast, A. aegypti was susceptible at both 10(9) and 10(7) PFU/mL doses, with body infection rates of 78% and 63%, and dissemination rates of 26% and 8%, respectively. The exclusion of vertebrates in its maintenance cycle may have facilitated the adaptation of EILV to a single

Reducing dose in paediatric CT: a preliminary study of radiographers' knowledge

International Nuclear Information System (INIS)

Heagney, J.; Lewis, S.; Chaffey, C.; Howlett, G.; Moran, A.; McLean, D.

2003-01-01

The objective of this study is to evaluate the responses of Australian radiographers in comparison with current literature on paediatric protocols and scanning recommendations in order to determine how and if paediatric Computed Tomography (CT) exposure reductions are taking place within Medical Imaging Departments. Subjects and Methods: The method involved a dual format; consisting of surveying 30 CT radiographers, and additionally, interviewing 5 senior CT radiographers. Of the 30 surveys completed, one was completed by a PDY radiographer, 7 by CT Senior radiographers and 22 by CT radiographers. The survey contained a range of questions about appropriate paediatric CT scanning parameters and protocols. Five CT Seniors were interviewed to ascertain the current level and opinion of training in paediatric protocols, in-house educational programs and the implementation of radiation dose saving parameters. Radiographers demonstrated reasonable ability to identify suitable paediatric protocols and believed the in-house CT protocols resident to their medical imaging department to be adequate, despite many utilising exposures higher than those from recommended literature. The interviews revealed that no further training in CT paediatric dose reduction was currently available, however survey responses indicated that further training would be beneficial. This study demonstrates that radiographers are aware of the need to reduce exposure parameters for paediatric CT and tend to follow protocols in place within their workplace, regardless of suitability and patient needs. Copyright (2003) Australian Institute of Radiography

Reducing dose in paediatric CT: a preliminary study of radiographers' Knowledge

International Nuclear Information System (INIS)

Heagney, Jillian; Lewis, Sarah; Chaffey, Clare; Howlett, Genevieve; Moran, Alexander; McLean, Donald

2003-01-01

The objective of this study is to evaluate the responses of Australian radiographers in comparison with current literature on paediatric protocols and scanning recommendations in order to determine how and if paediatric Computed Tomography (CT) exposure reductions are taking place within Medical Imaging Departments. Subjects and Methods: The method involved a dual format; consisting of surveying 30 CT radiographers, and additionally, interviewing 5 senior CT radiographers. Of the 30 surveys completed, one was completed by a PDY radiographer, 7 by CT Senior radiographers and 22 by CT radiographers. The survey contained a range of questions about appropriate paediatric CT scanning parameters and protocols. Five CT Seniors were interviewed to ascertain the current level and opinion of training in paediatric protocols, in-house educational programs and the implementation of radiation dose saving parameters. Radiographers demonstrated reasonable ability to identify suitable paediatric protocols and believed the in-house CT protocols resident to their medical imaging department to be adequate, despite many utilising exposures higher than those from recommended literature. The interviews revealed that no further training in CT paediatric dose reduction was currently available, however survey responses indicated that further training would be beneficial. This study demonstrates that radiographers are aware of the need to reduce exposure parameters for paediatric CT and tend to follow protocols in place within their workplace, regardless of suitability and patient needs Copyright (2003) Australian Institute of Radiography

Safety and immunogenicity of adenovirus-vectored near-consensus HIV type 1 clade B gag vaccines in healthy adults.

Science.gov (United States)

Harro, Clayton D; Robertson, Michael N; Lally, Michelle A; O'Neill, Lori D; Edupuganti, Srilatha; Goepfert, Paul A; Mulligan, Mark J; Priddy, Frances H; Dubey, Sheri A; Kierstead, Lisa S; Sun, Xiao; Casimiro, Danilo R; DiNubile, Mark J; Shiver, John W; Leavitt, Randi Y; Mehrotra, Devan V

2009-01-01

Vaccines inducing pathogen-specific cell-mediated immunity are being developed using attenuated adenoviral (Ad) vectors. We report the results of two independent Phase I trials of similar replication-deficient Ad5 vaccines containing a near-consensus HIV-1 clade B gag transgene. Healthy HIV-uninfected adults were enrolled in two separate, multicenter, dose-escalating, blinded, placebo-controlled studies to assess the safety and immunogenicity of a three-dose homologous regimen of Ad5 and MRKAd5 HIV-1 gag vaccines given on day 1, week 4, and week 26. Adverse events were collected for 29 days following each intradeltoid injection. The primary immunogenicity endpoint was the proportion of subjects with a positive unfractionated Gag-specific IFN-gamma ELISPOT response measured 4 weeks after the last dose (week 30). Analyses were performed after combining data for each dose group from both protocols, stratifying by baseline Ad5 titers. Overall, 252 subjects were randomized to receive either vaccine or placebo, including 229 subjects (91%) who completed the study through week 30. Tolerability and immunogenicity did not appear to differ between the Ad5 and MRKAd5 vaccines. The frequency of injection-site reactions was dose dependent. Systemic adverse events were also dose dependent and more frequent in subjects with baseline Ad5 titers or =200, especially after the first dose. The percent of ELISPOT responders and the ELISPOT geometric means overall were significantly higher for all four vaccine doses studied compared to placebo, and were generally higher in vaccine recipients with baseline Ad5 titers or = 200. Ad5 titers increased after vaccination in a dose-dependent fashion. Both Ad5-vectored HIV-1 vaccines were generally well tolerated and induced cell-mediated immune responses against HIV Gag-peptides in the majority of healthy adults with baseline Ad5 titers vaccine-induced immunity to the Ad5 vector may dampen the CMI response to HIV Gag.

Dose-reduced CT with model-based iterative reconstruction in evaluations of hepatic steatosis: How low can we go?

Energy Technology Data Exchange (ETDEWEB)

Yasaka, Koichiro, E-mail: koyasaka@gmail.com [Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655 (Japan); Katsura, Masaki [Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655 (Japan); Akahane, Masaaki [NTT Medical Center Tokyo, 5-9-22 Higashi-Gotanda, Shinagawa-ku, Tokyo 141-8625 (Japan); Sato, Jiro [Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655 (Japan); Matsuda, Izuru [Kanto Rosai Hospital, 1-1 Kizukisumiyoshi-cho, Nakahara-ku, Kawasaki, Kanagawa 211-8510 (Japan); Ohtomo, Kuni [Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655 (Japan)

2014-07-15

Purpose: To determine whether dose-reduced CT with model-based iterative image reconstruction (MBIR) is a useful tool with which to diagnose hepatic steatosis. Materials and methods: This prospective clinical study approved by our Institutional Review Board included 103 (67 men and 36 women; mean age, 64.3 years) patients who provided written informed consent to undergo unenhanced CT. Images of reference-dose CT (RDCT) with filtered back projection (R-FBP) and low- and ultralow-dose CT (dose-length product; 24 and 9% of that of RDCT) with MBIR (L-MBIR and UL-MBIR) were reconstructed. Mean CT numbers of liver (CT[L]) and spleen (CT[S]), and quotient (CT[L/S]) of CT[L] and CT[S] were calculated from selected regions of interest. Bias and limits of agreement (LOA) of CT[L] and CT[L/S] in L-MBIR and UL-MBIR (vs. R-FBP) were assessed using Bland–Altman analyses. Diagnostic methods for hepatic steatosis of CT[L] < 48 Hounsfield units (HU) and CT[L/S] < 1.1 were applied to L-MBIR and UL-MBIR using R-FBP as the reference standard. Results: Bias was larger for CT[L] in UL-MBIR than in L-MBIR (−3.18 HU vs. −1.73 HU). The LOA of CT[L/S] was larger for UL-MBIR than for L-MBIR (±0.425 vs. ±0.245) and outliers were identified in CT[L/S] of UL-MBIR. Accuracy (0.92–0.95) and the area under the receiver operating characteristics curve (0.976–0.992) were high for each method, but some were slightly lower in UL-MBIR than L-MBIR. Conclusion: Dose-reduced CT reconstructed with MBIR is applicable to diagnose hepatic steatosis, however, a low dose of radiation might be preferable.

Deep inspiration breath-hold technique for lung tumors: the potential value of target immobilization and reduced lung density in dose escalation

International Nuclear Information System (INIS)

Hanley, J.; Debois, M.M.; Raben, A.; Mageras, G.S.; Lutz, W.R.; Mychalczak, B.; Schwartz, L.H.; Gloeggler, P.J.; Leibel, S.A.; Fuks, Z.; Kutcher, G.J.

1996-01-01

Purpose/Objective: Lung tumors are subject to movement due to respiratory motion. Conventionally, a margin is applied to the clinical target volume (CTV) to account for this and other treatment uncertainties. The purpose of this study is to evaluate the dosimetric benefits of a deep inspiration breath-hold (DIBH) technique which has two distinct features - deep inspiration which reduces lung density and breath-hold which immobilizes lung tumors. Both properties can potentially reduce the mass of normal lung tissue in the high dose region, thus improving the possibility of dose escalation. Methods and Materials: To study the efficacy of the DIBH technique, CT scans are acquired for each patient under 4 respiration conditions: free-breathing; DIBH; shallow inspiration breath-hold; shallow expiration breath-hold. The free-breathing and DIBH scans are used to generate treatment plans for comparison of standard and DIBH techniques, while the shallow inspiration and expiration scans provide information on the maximum extent of tumor motion under free-breathing conditions. To acquire the breath-hold scans, the patients are brought to reproducible respiration levels using spirometry and slow vital capacity maneuvers. For the treatment plan comparison free-breathing and DIBH planning target volumes (PTVs) are constructed consisting of the CTV plus a margin for setup error and lung tumor motion. For both plans the margin for setup error is the same while the margin for lung tumor motion differs. The margin for organ motion in free-breathing is determined by the maximum tumor excursions in the shallow inspiration and expiration CT scans. For the DIBH, tumor motion is reduced to the extent to which DIBH can be maintained and the margin for any residual tumor motion is determined from repeat fluoroscopic movies, acquired with the patient monitored using spirometry. Three-dimensional treatment plans, generated using apertures based on the free-breathing and DIBH PTVs, are

Vector analysis

CERN Document Server

Brand, Louis

2006-01-01

The use of vectors not only simplifies treatments of differential geometry, mechanics, hydrodynamics, and electrodynamics, but also makes mathematical and physical concepts more tangible and easy to grasp. This text for undergraduates was designed as a short introductory course to give students the tools of vector algebra and calculus, as well as a brief glimpse into these subjects' manifold applications. The applications are developed to the extent that the uses of the potential function, both scalar and vector, are fully illustrated. Moreover, the basic postulates of vector analysis are brou

Effectiveness of Large-Scale Chagas Disease Vector Control Program in Nicaragua by Residual Insecticide Spraying Against Triatoma dimidiata.

Science.gov (United States)

Yoshioka, Kota; Nakamura, Jiro; Pérez, Byron; Tercero, Doribel; Pérez, Lenin; Tabaru, Yuichiro

2015-12-01

Chagas disease is one of the most serious health problems in Latin America. Because the disease is transmitted mainly by triatomine vectors, a three-phase vector control strategy was used to reduce its vector-borne transmission. In Nicaragua, we implemented an indoor insecticide spraying program in five northern departments to reduce house infestation by Triatoma dimidiata. The spraying program was performed in two rounds. After each round, we conducted entomological evaluation to compare the vector infestation level before and after spraying. A total of 66,200 and 44,683 houses were sprayed in the first and second spraying rounds, respectively. The entomological evaluation showed that the proportion of houses infested by T. dimidiata was reduced from 17.0% to 3.0% after the first spraying, which was statistically significant (P vector control strategies, and implementation of sustainable vector surveillance. © The American Society of Tropical Medicine and Hygiene.

Environmental and biological factors influencing Culex pipiens quinquefasciatus Say (Diptera: Culicidae) vector competence for Saint Louis encephalitis virus.

Science.gov (United States)

Richards, Stephanie L; Lord, Cynthia C; Pesko, Kendra; Tabachnick, Walter J

2009-08-01

Complex interactions between environmental and biological factors influence the susceptibility of Culex pipiens quinquefasciatus to St. Louis encephalitis virus and could affect the epidemiology of virus transmission. Similar interactions could have epidemiologic implications for other vector-virus systems. We conducted an experiment to examine four such factors in combination: mosquito age, extrinsic incubation temperature (EIT), virus dose, and colony. The proportion of mosquitoes with body infections or disseminated infections varied between colonies, and was dependant on age, EIT, and dose. We also show that the probability of a body or leg infection interacted in complex ways between colonies, ages, EITs, and doses. The complex interactive effects of environmental and biological factors must be taken into account for studies of vector competence and epidemiology, especially when laboratory studies are used to generalize to natural transmission dynamics where the extent of variation is largely unknown.

Prospective evaluation of reduced dose computed tomography for the detection of low-contrast liver lesions. Direct comparison with concurrent standard dose imaging

International Nuclear Information System (INIS)

Pooler, B.D.; Lubner, Meghan G.; Kim, David H.; Chen, Oliver T.; Li, Ke; Chen, Guang-Hong; Pickhardt, Perry J.

2017-01-01

To prospectively compare the diagnostic performance of reduced-dose (RD) contrast-enhanced CT (CECT) with standard-dose (SD) CECT for detection of low-contrast liver lesions. Seventy adults with non-liver primary malignancies underwent abdominal SD-CECT immediately followed by RD-CECT, aggressively targeted at 60-70 % dose reduction. SD series were reconstructed using FBP. RD series were reconstructed with FBP, ASIR, and MBIR (Veo). Three readers - blinded to clinical history and comparison studies - reviewed all series, identifying liver lesions ≥4 mm. Non-blinded review by two experienced abdominal radiologists - assessing SD against available clinical and radiologic information - established the reference standard. RD-CECT mean effective dose was 2.01 ± 1.36 mSv (median, 1.71), a 64.1 ± 8.8 % reduction. Pooled per-patient performance data were (sensitivity/specificity/PPV/NPV/accuracy) 0.91/0.78/0.60/0.96/0.81 for SD-FBP compared with RD-FBP 0.79/0.75/0.54/0.91/0.76; RD-ASIR 0.84/0.75/0.56/0.93/0.78; and RD-MBIR 0.84/0.68/0.49/0.92/0.72. ROC AUC values were 0.896/0.834/0.858/0.854 for SD-FBP/RD-FBP/RD-ASIR/RD-MBIR, respectively. RD-FBP (P = 0.002) and RD-MBIR (P = 0.032) AUCs were significantly lower than those of SD-FBP; RD-ASIR was not (P = 0.052). Reader confidence was lower for all RD series (P < 0.001) compared with SD-FBP, especially when calling patients entirely negative. Aggressive CT dose reduction resulted in inferior diagnostic performance and reader confidence for detection of low-contrast liver lesions compared to SD. Relative to RD-ASIR, RD-FBP showed decreased sensitivity and RD-MBIR showed decreased specificity. (orig.)

Prospective evaluation of reduced dose computed tomography for the detection of low-contrast liver lesions. Direct comparison with concurrent standard dose imaging

Energy Technology Data Exchange (ETDEWEB)

Pooler, B.D.; Lubner, Meghan G.; Kim, David H.; Chen, Oliver T. [University of Wisconsin School of Medicine and Public Health, Department of Radiology, Madison, WI (United States); Li, Ke; Chen, Guang-Hong [University of Wisconsin School of Medicine and Public Health, Department of Radiology, Madison, WI (United States); University of Wisconsin School of Medicine and Public Health, Department of Medical Physics, Madison, WI (United States); Pickhardt, Perry J. [University of Wisconsin School of Medicine and Public Health, Department of Radiology, Madison, WI (United States); University of Wisconsin School of Medicine and Public Health, E3/311 Clinical Science Center, Department of Radiology, Madison, WI (United States)

2017-05-15

To prospectively compare the diagnostic performance of reduced-dose (RD) contrast-enhanced CT (CECT) with standard-dose (SD) CECT for detection of low-contrast liver lesions. Seventy adults with non-liver primary malignancies underwent abdominal SD-CECT immediately followed by RD-CECT, aggressively targeted at 60-70 % dose reduction. SD series were reconstructed using FBP. RD series were reconstructed with FBP, ASIR, and MBIR (Veo). Three readers - blinded to clinical history and comparison studies - reviewed all series, identifying liver lesions ≥4 mm. Non-blinded review by two experienced abdominal radiologists - assessing SD against available clinical and radiologic information - established the reference standard. RD-CECT mean effective dose was 2.01 ± 1.36 mSv (median, 1.71), a 64.1 ± 8.8 % reduction. Pooled per-patient performance data were (sensitivity/specificity/PPV/NPV/accuracy) 0.91/0.78/0.60/0.96/0.81 for SD-FBP compared with RD-FBP 0.79/0.75/0.54/0.91/0.76; RD-ASIR 0.84/0.75/0.56/0.93/0.78; and RD-MBIR 0.84/0.68/0.49/0.92/0.72. ROC AUC values were 0.896/0.834/0.858/0.854 for SD-FBP/RD-FBP/RD-ASIR/RD-MBIR, respectively. RD-FBP (P = 0.002) and RD-MBIR (P = 0.032) AUCs were significantly lower than those of SD-FBP; RD-ASIR was not (P = 0.052). Reader confidence was lower for all RD series (P < 0.001) compared with SD-FBP, especially when calling patients entirely negative. Aggressive CT dose reduction resulted in inferior diagnostic performance and reader confidence for detection of low-contrast liver lesions compared to SD. Relative to RD-ASIR, RD-FBP showed decreased sensitivity and RD-MBIR showed decreased specificity. (orig.)

Vectors and Rotations in 3-Dimensions: Vector Algebra for the C++ Programmer

Science.gov (United States)

2016-12-01

release; distribution is unlimited. 1. Introduction This report describes 2 C++ classes: a Vector class for performing vector algebra in 3-dimensional...ARL-TR-7894•DEC 2016 US Army Research Laboratory Vectors and Rotations in 3-Dimensions:Vector Algebra for the C++ Programmer by Richard Saucier...Army Research Laboratory Vectors and Rotations in 3-Dimensions:Vector Algebra for the C++ Programmer by Richard Saucier Survivability/Lethality

Genetic modification of lymphocytes by retrovirus-based vectors.

Science.gov (United States)

Suerth, Julia D; Schambach, Axel; Baum, Christopher

2012-10-01

The genetic modification of lymphocytes is an important topic in the emerging field of gene therapy. Many clinical trials targeting immunodeficiency syndromes or cancer have shown therapeutic benefit; further applications address inflammatory and infectious disorders. Retroviral vector development requires a detailed understanding of the interactions with the host. Most researchers have used simple gammaretroviral vectors to modify lymphocytes, either directly or via hematopoietic stem and progenitor cells. Lentiviral, spumaviral (foamyviral) and alpharetroviral vectors were designed to reduce the necessity for cell stimulation and to utilize potentially safer integration properties. Novel surface modifications (pseudotyping) and transgenes, built using synthetic components, expand the retroviral toolbox, altogether promising increased specificity and potency. Product consistency will be an important criterion for routine clinical use. Copyright © 2012. Published by Elsevier Ltd.

Reducing radiation dose in adult head CT using iterative reconstruction. A clinical study in 177 patients

Energy Technology Data Exchange (ETDEWEB)

Kaul, D. [Charite School of Medicine and University Hospital, Berlin (Germany). Dept. of Radiology; Charite School of Medicine and University Hospital, Berlin (Germany). Dept. of Radiation Oncology; Kahn, J.; Huizing, L.; Wiener, E.; Grupp, U.; Boening, G.; Streitparth, F. [Charite School of Medicine and University Hospital, Berlin (Germany). Dept. of Radiology; Ghadjar, P. [Charite School of Medicine and University Hospital, Berlin (Germany). Dept. of Radiation Oncology; Renz, D.M. [Jena University Hospital (Germany). Dept. of Radiology

2016-02-15

To assess how ASIR (adaptive statistical iterative reconstruction) contributes to dose reduction and affects image quality of non-contrast cranial computed tomography (cCT). Non-contrast emergency CT scans of the head acquired in 177 patients were evaluated. The scans were acquired and processed using four different protocols: Group A (control): 120 kV, FBP (filtered back projection) n=71; group B1: 120 kV, scan and reconstruction performed with 20 % ASIR (blending of 20 % ASIR and 80 % FBP), n=86; group B2: raw data from group B1 reconstructed using a blending of 40 % ASIR and 60 % FBP, n=74; group C1: 120 kV, scan and reconstruction performed with 30 % ASIR, n=20; group C2: raw data from group C1 reconstructed using a blending of 50 % ASIR and 50 % FBP, n=20. The effective dose was calculated. Image quality was assessed quantitatively and qualitatively. Compared to group A, groups B1/2 and C1/2 showed a significantly reduced effective dose of 40.4 % and 73.3 % (p < 0.0001), respectively. Group B1 and group C1/2 also showed significantly reduced quantitative and qualitative image quality parameters. In group B2, quantitative measures were comparable to group A, and qualitative scores were lower compared to group A but higher compared to group B1. Diagnostic confidence grading showed groups B1/2 to be adequate for everyday clinical practice. Group C2 was considered acceptable for follow-up imaging of severe acute events such as bleeding or subacute stroke. Conclusion: Use of ASIR makes it possible to reduce radiation significantly while maintaining adequate image quality in non-contrast head CT, which may be particularly useful for younger patients in an emergency setting and in follow-up.

Reducing Radiation Dose in Adult Head CT using Iterative Reconstruction - A Clinical Study in 177 Patients.

Science.gov (United States)

Kaul, D; Kahn, J; Huizing, L; Wiener, E; Grupp, U; Böning, G; Ghadjar, P; Renz, D M; Streitparth, F

2016-02-01

To assess how ASIR (adaptive statistical iterative reconstruction) contributes to dose reduction and affects image quality of non-contrast cranial computed tomography (cCT). Non-contrast emergency CT scans of the head acquired in 177 patients were evaluated. The scans were acquired and processed using four different protocols: Group A (control): 120 kV, FBP (filtered back projection) n = 71; group B1: 120 kV, scan and reconstruction performed with 20 % ASIR (blending of 20 % ASIR and 80 % FBP), n = 86; group B2: raw data from group B1 reconstructed using a blending of 40 % ASIR and 60 % FBP, n = 74; group C1: 120 kV, scan and reconstruction performed with 30 % ASIR, n = 20; group C2: raw data from group C1 reconstructed using a blending of 50 % ASIR and 50 % FBP, n = 20. The effective dose was calculated. Image quality was assessed quantitatively and qualitatively. Compared to group A, groups B1/2 and C1/2 showed a significantly reduced effective dose of 40.4 % and 73.3 % (p ASIR makes it possible to reduce radiation significantly while maintaining adequate image quality in non-contrast head CT, which may be particularly useful for younger patients in an emergency setting and in follow-up. ASIR may reduce radiation significantly while maintaining adequate image quality. cCT protocol with 20 % ASIR and 40 %ASIR/60 %FBP blending is adequate for everyday clinical use. cCT protocol with 30 % ASIR and 50 %ASIR/50 %FBP blending is adequate for follow-up imaging © Georg Thieme Verlag KG Stuttgart · New York.

Reducing radiation dose in adult head CT using iterative reconstruction. A clinical study in 177 patients

International Nuclear Information System (INIS)

Kaul, D.; Charite School of Medicine and University Hospital, Berlin; Kahn, J.; Huizing, L.; Wiener, E.; Grupp, U.; Boening, G.; Streitparth, F.; Ghadjar, P.; Renz, D.M.

2016-01-01

To assess how ASIR (adaptive statistical iterative reconstruction) contributes to dose reduction and affects image quality of non-contrast cranial computed tomography (cCT). Non-contrast emergency CT scans of the head acquired in 177 patients were evaluated. The scans were acquired and processed using four different protocols: Group A (control): 120 kV, FBP (filtered back projection) n=71; group B1: 120 kV, scan and reconstruction performed with 20 % ASIR (blending of 20 % ASIR and 80 % FBP), n=86; group B2: raw data from group B1 reconstructed using a blending of 40 % ASIR and 60 % FBP, n=74; group C1: 120 kV, scan and reconstruction performed with 30 % ASIR, n=20; group C2: raw data from group C1 reconstructed using a blending of 50 % ASIR and 50 % FBP, n=20. The effective dose was calculated. Image quality was assessed quantitatively and qualitatively. Compared to group A, groups B1/2 and C1/2 showed a significantly reduced effective dose of 40.4 % and 73.3 % (p < 0.0001), respectively. Group B1 and group C1/2 also showed significantly reduced quantitative and qualitative image quality parameters. In group B2, quantitative measures were comparable to group A, and qualitative scores were lower compared to group A but higher compared to group B1. Diagnostic confidence grading showed groups B1/2 to be adequate for everyday clinical practice. Group C2 was considered acceptable for follow-up imaging of severe acute events such as bleeding or subacute stroke. Conclusion: Use of ASIR makes it possible to reduce radiation significantly while maintaining adequate image quality in non-contrast head CT, which may be particularly useful for younger patients in an emergency setting and in follow-up.

Occupational dose constraint

International Nuclear Information System (INIS)

Heilbron Filho, Paulo Fernando Lavalle; Xavier, Ana Maria

2005-01-01

The revision process of the international radiological protection regulations has resulted in the adoption of new concepts, such as practice, intervention, avoidable and restriction of dose (dose constraint). The latter deserving of special mention since it may involve reducing a priori of the dose limits established both for the public and to individuals occupationally exposed, values that can be further reduced, depending on the application of the principle of optimization. This article aims to present, with clarity, from the criteria adopted to define dose constraint values to the public, a methodology to establish the dose constraint values for occupationally exposed individuals, as well as an example of the application of this methodology to the practice of industrial radiography

Measurement of Charmless B to Vector-Vector decays at BaBar

International Nuclear Information System (INIS)

Olaiya, Emmanuel

2011-01-01

The authors present results of B → vector-vector (VV) and B → vector-axial vector (VA) decays B 0 → φX(X = φ,ρ + or ρ 0 ), B + → φK (*)+ , B 0 → K*K*, B 0 → ρ + b 1 - and B + → K* 0 α 1 + . The largest dataset used for these results is based on 465 x 10 6 Υ(4S) → B(bar B) decays, collected with the BABAR detector at the PEP-II B meson factory located at the Stanford Linear Accelerator Center (SLAC). Using larger datasets, the BABAR experiment has provided more precise B → VV measurements, further supporting the smaller than expected longitudinal polarization fraction of B → φK*. Additional B meson to vector-vector and vector-axial vector decays have also been studied with a view to shedding light on the polarization anomaly. Taking into account the available errors, we find no disagreement between theory and experiment for these additional decays.

Dose reduction in evacuation proctography

International Nuclear Information System (INIS)

Hare, C.; Halligan, S.; Bartram, C.I.; Gupta, R.; Walker, A.E.; Renfrew, I.

2001-01-01

The goal of this study was to reduce the patient radiation dose from evacuation proctography. Ninety-eight consecutive adult patients referred for proctography to investigate difficult rectal evacuation were studied using a digital imaging system with either a standard digital program for barium examinations, a reduced dose digital program (both with and without additional copper filtration), or Video fluoroscopy. Dose-area products were recorded for each examination and the groups were compared. All four protocols produced technically acceptable examinations. The low-dose program with copper filtration (median dose 382 cGy cm 2 ) and Video fluoroscopy (median dose 705 cGy cm 2 ) were associated with significantly less dose than other groups (p < 0.0001). Patient dose during evacuation proctography can be reduced significantly without compromising the diagnostic quality of the examination. A digital program with added copper filtration conveyed the lowest dose. (orig.)

Low-Dose Epinephrine Plus Tranexamic Acid Reduces Early Postoperative Blood Loss and Inflammatory Response: A Randomized Controlled Trial.

Science.gov (United States)

Zeng, Wei-Nan; Liu, Jun-Li; Wang, Fu-You; Chen, Cheng; Zhou, Qiang; Yang, Liu

2018-02-21

The reductions of perioperative blood loss and inflammatory response are important in total knee arthroplasty. Tranexamic acid reduced blood loss and the inflammatory response in several studies. However, the effect of epinephrine administration plus tranexamic acid has not been intensively investigated, to our knowledge. In this study, we evaluated whether the combined administration of low-dose epinephrine plus tranexamic acid reduced perioperative blood loss or inflammatory response further compared with tranexamic acid alone. This randomized placebo-controlled trial consisted of 179 consecutive patients who underwent primary total knee arthroplasty. Patients were randomized into 3 interventions: Group IV received intravenous low-dose epinephrine plus tranexamic acid, Group TP received topical diluted epinephrine plus tranexamic acid, and Group CT received tranexamic acid alone. The primary outcome was perioperative blood loss on postoperative day 1. Secondary outcomes included perioperative blood loss on postoperative day 3, coagulation and fibrinolysis parameters (measured by thromboelastography), inflammatory cytokine levels, transfusion values (rate and volume), thromboembolic complications, length of hospital stay, wound score, range of motion, and Hospital for Special Surgery (HSS) score. The mean calculated total blood loss (and standard deviation) in Group IV was 348.1 ± 158.2 mL on postoperative day 1 and 458.0 ± 183.4 mL on postoperative day 3, which were significantly reduced (p 0.05). The combined administration of low-dose epinephrine and tranexamic acid demonstrated an increased effect in reducing perioperative blood loss and the inflammatory response compared with tranexamic acid alone, with no apparent increased incidence of thromboembolic and other complications. Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Efficacy of virtual block objects in reducing the lung dose in helical tomotherapy planning for cervical oesophageal cancer: a planning study.

Science.gov (United States)

Ito, Makoto; Shimizu, Hidetoshi; Aoyama, Takahiro; Tachibana, Hiroyuki; Tomita, Natsuo; Makita, Chiyoko; Koide, Yutaro; Kato, Daiki; Ishiguchi, Tsuneo; Kodaira, Takeshi

2018-04-04

Intensity-modulated radiotherapy is useful for cervical oesophageal carcinoma (CEC); however, increasing low-dose exposure to the lung may lead to radiation pneumonitis. Nevertheless, an irradiation technique that avoids the lungs has never been examined due to the high difficulty of dose optimization. In this study, we examined the efficacy of helical tomotherapy that can restrict beamlets passing virtual blocks during dose optimization computing (block plan) in reducing the lung dose. Fifteen patients with CEC were analysed. The primary/nodal lesion and prophylactic nodal region with adequate margins were defined as the planning target volume (PTV)-60 Gy and PTV-48 Gy, respectively. Nineteen plans per patient were made and compared (total: 285 plans), including non-block and block plans with several shapes and sizes. The most appropriate block model was semi-circular, 8 cm outside of the tracheal bifurcation, with a significantly lower lung dose compared to that of non-block plans; the mean lung volumes receiving 5 Gy, 10 Gy, 20 Gy, and the mean lung dose were 31.3% vs. 48.0% (p block and non-block plans were comparable in terms of the homogeneity and conformity indexes of PTV-60 Gy: 0.05 vs. 0.04 (p = 0.100) and 0.82 vs. 0.85 (p = 0.616), respectively. The maximum dose of the spinal cord planning risk volume increased slightly (49.4 Gy vs. 47.9 Gy, p = 0.002). There was no significant difference in the mean doses to the heart and the thyroid gland. Prolongation of the delivery time was less than 1 min (5.6 min vs. 4.9 min, p = 0.010). The block plan for CEC could significantly reduce the lung dose, with acceptable increment in the spinal dose and a slightly prolonged delivery time.

Representation and display of vector field topology in fluid flow data sets

Science.gov (United States)

Helman, James; Hesselink, Lambertus

1989-01-01

The visualization of physical processes in general and of vector fields in particular is discussed. An approach to visualizing flow topology that is based on the physics and mathematics underlying the physical phenomenon is presented. It involves determining critical points in the flow where the velocity vector vanishes. The critical points, connected by principal lines or planes, determine the topology of the flow. The complexity of the data is reduced without sacrificing the quantitative nature of the data set. By reducing the original vector field to a set of critical points and their connections, a representation of the topology of a two-dimensional vector field that is much smaller than the original data set but retains with full precision the information pertinent to the flow topology is obtained. This representation can be displayed as a set of points and tangent curves or as a graph. Analysis (including algorithms), display, interaction, and implementation aspects are discussed.

Large-scale adenovirus and poxvirus-vectored vaccine manufacturing to enable clinical trials.

Science.gov (United States)

Kallel, Héla; Kamen, Amine A

2015-05-01

Efforts to make vaccines against infectious diseases and immunotherapies for cancer have evolved to utilize a variety of heterologous expression systems such as viral vectors. These vectors are often attenuated or engineered to safely deliver genes encoding antigens of different pathogens. Adenovirus and poxvirus vectors are among the viral vectors that are most frequently used to develop prophylactic vaccines against infectious diseases as well as therapeutic cancer vaccines. This mini-review describes the trends and processes in large-scale production of adenovirus and poxvirus vectors to meet the needs of clinical applications. We briefly describe the general principles for the production and purification of adenovirus and poxvirus viral vectors. Currently, adenovirus and poxvirus vector manufacturing methods rely on well-established cell culture technologies. Several improvements have been evaluated to increase the yield and to reduce the overall manufacturing cost, such as cultivation at high cell densities and continuous downstream processing. Additionally, advancements in vector characterization will greatly facilitate the development of novel vectored vaccine candidates. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lentiviral vector mediated modification of mesenchymal stem cells & enhanced survival in an in vitro model of ischaemia.

LENUS (Irish Health Repository)

McGinley, Lisa

2012-01-31

INTRODUCTION: A combination of gene and cell therapies has the potential to significantly enhance the therapeutic value of mesenchymal stem cells (MSCs). The development of efficient gene delivery methods is essential if MSCs are to be of benefit using such an approach. Achieving high levels of transgene expression for the required period of time, without adversely affecting cell viability and differentiation capacity, is crucial. In the present study, we investigate lentiviral vector-mediated genetic modification of rat bone-marrow derived MSCs and examine any functional effect of such genetic modification in an in vitro model of ischaemia. METHODS: Transduction efficiency and transgene persistence of second and third generation rHIV-1 based lentiviral vectors were tested using reporter gene constructs. Use of the rHIV-pWPT-EF1-alpha-GFP-W vector was optimised in terms of dose, toxicity, cell species, and storage. The in vivo condition of ischaemia was modelled in vitro by separation into its associated constituent parts i.e. hypoxia, serum and glucose deprivation, in which the effect of therapeutic gene over-expression on MSC survival was investigated. RESULTS: The second generation lentiviral vector rHIV-pWPT-EF1-alpha-GFP-W, was the most efficient and provided the most durable transgene expression of the vectors tested. Transduction with this vector did not adversely affect MSC morphology, viability or differentiation potential, and transgene expression levels were unaffected by cryopreservation of transduced cells. Over-expression of HSP70 resulted in enhanced MSC survival and increased resistance to apoptosis in conditions of hypoxia and ischaemia. MSC differentiation capacity was significantly reduced after oxygen deprivation, but was preserved with HSP70 over-expression. CONCLUSIONS: Collectively, these data validate the use of lentiviral vectors for efficient in vitro gene delivery to MSCs and suggest that lentiviral vector transduction can facilitate

Lentiviral vector mediated modification of mesenchymal stem cells & enhanced survival in an in vitro model of ischaemia

LENUS (Irish Health Repository)

McGinley, Lisa

2011-03-07

Abstract Introduction A combination of gene and cell therapies has the potential to significantly enhance the therapeutic value of mesenchymal stem cells (MSCs). The development of efficient gene delivery methods is essential if MSCs are to be of benefit using such an approach. Achieving high levels of transgene expression for the required period of time, without adversely affecting cell viability and differentiation capacity, is crucial. In the present study, we investigate lentiviral vector-mediated genetic modification of rat bone-marrow derived MSCs and examine any functional effect of such genetic modification in an in vitro model of ischaemia. Methods Transduction efficiency and transgene persistence of second and third generation rHIV-1 based lentiviral vectors were tested using reporter gene constructs. Use of the rHIV-pWPT-EF1-α-GFP-W vector was optimised in terms of dose, toxicity, cell species, and storage. The in vivo condition of ischaemia was modelled in vitro by separation into its associated constituent parts i.e. hypoxia, serum and glucose deprivation, in which the effect of therapeutic gene over-expression on MSC survival was investigated. Results The second generation lentiviral vector rHIV-pWPT-EF1-α-GFP-W, was the most efficient and provided the most durable transgene expression of the vectors tested. Transduction with this vector did not adversely affect MSC morphology, viability or differentiation potential, and transgene expression levels were unaffected by cryopreservation of transduced cells. Over-expression of HSP70 resulted in enhanced MSC survival and increased resistance to apoptosis in conditions of hypoxia and ischaemia. MSC differentiation capacity was significantly reduced after oxygen deprivation, but was preserved with HSP70 over-expression. Conclusions Collectively, these data validate the use of lentiviral vectors for efficient in vitro gene delivery to MSCs and suggest that lentiviral vector transduction can facilitate

Reduced time for urinary alkalinization before high-dose methotrexate with preadmission oral bicarbonate.

Science.gov (United States)

Kintzel, Polly E; Campbell, Alan D; Yost, Kathleen J; Brinker, Brett T; Arradaza, Nicole V; Frobish, Daniel; Wehr, Alison M; O'Rourke, Timothy J

2012-06-01

Hydration and urinary alkalinization are essential for reducing renal dysfunction with high dose methotrexate (HDMTX). This report presents an analysis of institutional methods used to achieve adequate urinary alkalinization and output for patients receiving single agent HDMTX. Renal and metabolic parameters of tolerance were examined. Medical records of adult patients receiving HDMTX during the calendar years of 2008-2009 were retrospectively reviewed to determine the time to achieve urine pH > 7. Number of hospital days, bicarbonate dose, ordered hydration rate, urine output, and urine pH were assessed. A survival analysis model was run for time to urine pH > 7 using preadmission oral bicarbonate as a predictor variable and including a frailty term. Observational statistics were performed for other parameters. The analysis included 79 encounters for ten patients. Urine pH > 7 was achieved more rapidly in patients receiving preadmission oral bicarbonate (P = 0.012). The number of patients receiving HDMTX on the same day as admission was greater for those receiving preadmission oral bicarbonate (47%) in comparison to those who did not (2%), and they spent less time in the hospital. A standard regimen for hydration and urinary alkalinization based on this project is reported. The nature and frequency of adverse events were as expected for this treatment. At our institution, the time to achieve urinary alkalinization was reduced for patients receiving preadmission oral bicarbonate which facilitated chemotherapy infusion on the same day as admission and decreased the number of calendar days that patients stayed in the hospital.

Influence of model based iterative reconstruction algorithm on image quality of multiplanar reformations in reduced dose chest CT

International Nuclear Information System (INIS)

Barras, Heloise; Dunet, Vincent; Hachulla, Anne-Lise; Grimm, Jochen; Beigelman-Aubry, Catherine

2016-01-01

Model-based iterative reconstruction (MBIR) reduces image noise and improves image quality (IQ) but its influence on post-processing tools including maximal intensity projection (MIP) and minimal intensity projection (mIP) remains unknown. To evaluate the influence on IQ of MBIR on native, mIP, MIP axial and coronal reformats of reduced dose computed tomography (RD-CT) chest acquisition. Raw data of 50 patients, who underwent a standard dose CT (SD-CT) and a follow-up RD-CT with a CT dose index (CTDI) of 2–3 mGy, were reconstructed by MBIR and FBP. Native slices, 4-mm-thick MIP, and 3-mm-thick mIP axial and coronal reformats were generated. The relative IQ, subjective IQ, image noise, and number of artifacts were determined in order to compare different reconstructions of RD-CT with reference SD-CT. The lowest noise was observed with MBIR. RD-CT reconstructed by MBIR exhibited the best relative and subjective IQ on coronal view regardless of the post-processing tool. MBIR generated the lowest rate of artefacts on coronal mIP/MIP reformats and the highest one on axial reformats, mainly represented by distortions and stairsteps artifacts. The MBIR algorithm reduces image noise but generates more artifacts than FBP on axial mIP and MIP reformats of RD-CT. Conversely, it significantly improves IQ on coronal views, without increasing artifacts, regardless of the post-processing technique

Dose-reduction techniques for high-dose worker groups in nuclear power plants

International Nuclear Information System (INIS)

Khan, T.A.; Baum, J.W.; Dionne, B.J.

1991-03-01

This report summarizes the main findings of a study of the extent of radiation dose received by special work groups in the nuclear power industry. Work groups which chronically get large doses were investigated, using information provided by the industry. The tasks that give high doses to these work groups were examined and techniques described that were found to be particularly successful in reducing dose. Quantitative information on the extent of radiation doses to various work groups shows that significant numbers of workers in several critical groups receive doses greater than 1 and even 2 rem per year, particularly contract personnel and workers at BWR-type plants. The number of radiation workers whose lifetime dose is greater than their age is much less. Although the techniques presented would go some way in reducing dose, it is likely that a sizeable reduction to the high-dose work groups may require development of new dose-reduction techniques as well as major changes in procedures. 10 refs., 26 tabs

Vectorization of KENO IV code and an estimate of vector-parallel processing

International Nuclear Information System (INIS)

Asai, Kiyoshi; Higuchi, Kenji; Katakura, Jun-ichi; Kurita, Yutaka.

1986-10-01

The multi-group criticality safety code KENO IV has been vectorized and tested on FACOM VP-100 vector processor. At first the vectorized KENO IV on a scalar processor became slower than the original one by a factor of 1.4 because of the overhead introduced by the vectorization. Making modifications of algorithms and techniques for vectorization, the vectorized version has become faster than the original one by a factor of 1.4 and 3.0 on the vector processor for sample problems of complex and simple geometries, respectively. For further speedup of the code, some improvements on compiler and hardware, especially on addition of Monte Carlo pipelines to the vector processor, are discussed. Finally a pipelined parallel processor system is proposed and its performance is estimated. (author)

2D Vector Field Simplification Based on Robustness

KAUST Repository

Skraba, Primoz; Wang, Bei; Chen, Guoning; Rosen, Paul

2014-01-01

Vector field simplification aims to reduce the complexity of the flow by removing features in order of their relevance and importance, to reveal prominent behavior and obtain a compact representation for interpretation. Most existing simplification

Glymphatic fluid transport controls paravascular clearance of AAV vectors from the brain

Science.gov (United States)

Murlidharan, Giridhar; Crowther, Andrew; Reardon, Rebecca A.; Song, Juan

2016-01-01

Adeno-associated viruses (AAV) are currently being evaluated in clinical trials for gene therapy of CNS disorders. However, host factors that influence the spread, clearance, and transduction efficiency of AAV vectors in the brain are not well understood. Recent studies have demonstrated that fluid flow mediated by aquaporin-4 (AQP4) channels located on astroglial end feet is essential for exchange of solutes between interstitial and cerebrospinal fluid. This phenomenon, which is essential for interstitial clearance of solutes from the CNS, has been termed glial-associated lymphatic transport or glymphatic transport. In the current study, we demonstrate that glymphatic transport profoundly affects various aspects of AAV gene transfer in the CNS. Altered localization of AQP4 in aged mouse brains correlated with significantly increased retention of AAV vectors in the parenchyma and reduced systemic leakage following ventricular administration. We observed a similar increase in AAV retention and transgene expression upon i.c.v. administration in AQP4–/– mice. Consistent with this observation, fluorophore-labeled AAV vectors showed markedly reduced flux from the ventricles of AQP4–/– mice compared with WT mice. These results were further corroborated by reduced AAV clearance from the AQP4-null brain, as demonstrated by reduced transgene expression and vector genome accumulation in systemic organs. We postulate that deregulation of glymphatic transport in aged and diseased brains could markedly affect the parenchymal spread, clearance, and gene transfer efficiency of AAV vectors. Assessment of biomarkers that report the kinetics of CSF flux in prospective gene therapy patients might inform variable treatment outcomes and guide future clinical trial design. PMID:27699236

Dose-Reduced Trastuzumab Emtansine: Active and Safe in Acute Hepatic Dysfunction

Directory of Open Access Journals (Sweden)

Adam Sharp

2015-02-01

Full Text Available Breast cancer is the most common cancer in women worldwide. The majority of deaths attributed to breast cancer are a result of metastatic disease, and 30% of early breast cancers (EBC will develop distant disease. The 5-year survival of patients with metastatic disease is estimated at 23%. Breast cancer subtypes continue to be stratified histologically on oestrogen, progesterone and human epidermal growth factor-2 (HER2 receptor expression. HER2-positive breast cancers represent 25% of all breast cancer diagnoses. The therapies available for metastatic breast cancer (MBC are expanding, in particular within the field of HER2-positive disease, with the approval of trastuzumab, pertuzumab, lapatinib and trastuzumab emtansine (TDM-1. Recently, TDM-1 has been shown to improve progression-free survival in HER2 MBC when compared to capecitabine and lapatinib in clinical studies. Its main toxicities are deranged liver function tests and thrombocytopenia. There have also been cases of acute liver failure. Therefore, its use in acute hepatic dysfunction, to our knowledge, has been neither studied nor reported. We report a patient with progressive HER2-positive MBC who had previously responded to multiple HER2-targeted therapies that presented with acute hepatic dysfunction. She was treated with dose-reduced TDM-1 safely, with clear evidence of rapid biochemical, clinical and radiological response. This allowed dose escalation of TDM-1, and the patient maintains an ongoing response.

Analysis of Cumulative Dose to Implanted Pacemaker According to Various IMRT Delivery Methods: Optimal Dose Delivery Versus Dose Reduction Strategy

Energy Technology Data Exchange (ETDEWEB)

Lee, Jeong Woo; Hong, Se Mie [Dept. of Radiation Oncology, Konkuk University Medical Center, Seoul (Korea, Republic of)

2011-11-15

Cancer patients with implanted cardiac pacemaker occasionally require radiotherapy. Pacemaker may be damaged or malfunction during radiotherapy due to ionizing radiation or electromagnetic interference. Although radiotherapy should be planned to keep the dose to pacemaker as low as possible not to malfunction ideally, current radiation treatment planning (RTP) system does not accurately calculate deposited dose to adjacent field border or area beyond irradiated fields. In terms of beam delivery techniques using multiple intensity modulated fields, dosimetric effect of scattered radiation in high energy photon beams is required to be detailed analyzed based on measurement data. The aim of this study is to evaluate dose discrepancies of pacemaker in a RTP system as compared to measured doses. We also designed dose reduction strategy limited value of 2 Gy for radiation treatment patients with cardiac implanted pacemaker. Total accumulated dose of 145 cGy based on in-vivo dosimetry was satisfied with the recommendation criteria to prevent malfunction of pacemaker in SS technique. However, the 2 mm lead shielder enabled the scattered doses to reduce up to 60% and 40% in the patient and the phantom, respectively. The SS technique with the lead shielding could reduce the accumulated scattered doses less than 100 cGy. Calculated and measured doses were not greatly affected by the beam delivery techniques. In-vivo and measured doses on pacemaker position showed critical dose discrepancies reaching up to 4 times as compared to planned doses in RTP. The current SS technique could deliver lower scattered doses than recommendation criteria, but use of 2 mm lead shielder contributed to reduce scattered doses by 60%. The tertiary lead shielder can be useful to prevent malfunction or electrical damage of implanted pacemakers during radiotherapy. It is required to estimate more accurate scattered doses of the patient or medical device in RTP to design proper dose reduction strategy.

Analysis of Cumulative Dose to Implanted Pacemaker According to Various IMRT Delivery Methods: Optimal Dose Delivery Versus Dose Reduction Strategy

International Nuclear Information System (INIS)

Lee, Jeong Woo; Hong, Se Mie

2011-01-01

Cancer patients with implanted cardiac pacemaker occasionally require radiotherapy. Pacemaker may be damaged or malfunction during radiotherapy due to ionizing radiation or electromagnetic interference. Although radiotherapy should be planned to keep the dose to pacemaker as low as possible not to malfunction ideally, current radiation treatment planning (RTP) system does not accurately calculate deposited dose to adjacent field border or area beyond irradiated fields. In terms of beam delivery techniques using multiple intensity modulated fields, dosimetric effect of scattered radiation in high energy photon beams is required to be detailed analyzed based on measurement data. The aim of this study is to evaluate dose discrepancies of pacemaker in a RTP system as compared to measured doses. We also designed dose reduction strategy limited value of 2 Gy for radiation treatment patients with cardiac implanted pacemaker. Total accumulated dose of 145 cGy based on in-vivo dosimetry was satisfied with the recommendation criteria to prevent malfunction of pacemaker in SS technique. However, the 2 mm lead shielder enabled the scattered doses to reduce up to 60% and 40% in the patient and the phantom, respectively. The SS technique with the lead shielding could reduce the accumulated scattered doses less than 100 cGy. Calculated and measured doses were not greatly affected by the beam delivery techniques. In-vivo and measured doses on pacemaker position showed critical dose discrepancies reaching up to 4 times as compared to planned doses in RTP. The current SS technique could deliver lower scattered doses than recommendation criteria, but use of 2 mm lead shielder contributed to reduce scattered doses by 60%. The tertiary lead shielder can be useful to prevent malfunction or electrical damage of implanted pacemakers during radiotherapy. It is required to estimate more accurate scattered doses of the patient or medical device in RTP to design proper dose reduction strategy.

WE-AB-209-08: Novel Beam-Specific Adaptive Margins for Reducing Organ-At-Risk Doses

Energy Technology Data Exchange (ETDEWEB)

Tsang, H; Kamerling, CP; Ziegenhein, P; Nill, S; Oelfke, U [The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London (United Kingdom)

2016-06-15

Purpose: Current practice of using 3D margins in radiotherapy with high-energy photon beams provides larger-than-required target coverage. According to the photon depth-dose curve, target displacements in beam direction result in minute changes in dose delivered. We exploit this behavior by generating margins on a per-beam basis which simultaneously account for the relative distance of the target and adjacent organs-at-risk (OARs). Methods: For each beam, we consider only geometrical uncertainties of the target location perpendicular to beam direction. By weighting voxels based on its proximity to an OAR, we generate adaptive margins that yield similar overall target coverage probability and reduced OAR dose-burden, at the expense of increased target volume. Three IMRT plans, using 3D margins and 2D per-beam margins with and without adaptation, were generated for five prostate patients with a prescription dose Dpres of 78Gy in 2Gy fractions using identical optimisation constraints. Systematic uncertainties of 1.1, 1.1, 1.5mm in the LR, SI, and AP directions, respectively, and 0.9, 1.1, 1.0mm for the random uncertainties, were assumed. A verification tool was employed to simulate the effects of systematic and random errors using a population size of 50,000. The fraction of the population that satisfies or violates a given DVH constraint was used for comparison. Results: We observe similar target coverage across all plans, with at least 97.5% of the population meeting the D98%>95%Dpres constraint. When looking at the probability of the population receiving D5<70Gy for the rectum, we observed median absolute increases of 23.61% (range, 2.15%–27.85%) and 6.97% (range, 0.65%–17.76%) using per-beam margins with and without adaptation, respectively, relative to using 3D margins. Conclusion: We observed sufficient and similar target coverage using per-beam margins. By adapting each per-beam margin away from an OAR, we can further reduce OAR dose without significantly

WE-AB-209-08: Novel Beam-Specific Adaptive Margins for Reducing Organ-At-Risk Doses

International Nuclear Information System (INIS)

Tsang, H; Kamerling, CP; Ziegenhein, P; Nill, S; Oelfke, U

2016-01-01

Purpose: Current practice of using 3D margins in radiotherapy with high-energy photon beams provides larger-than-required target coverage. According to the photon depth-dose curve, target displacements in beam direction result in minute changes in dose delivered. We exploit this behavior by generating margins on a per-beam basis which simultaneously account for the relative distance of the target and adjacent organs-at-risk (OARs). Methods: For each beam, we consider only geometrical uncertainties of the target location perpendicular to beam direction. By weighting voxels based on its proximity to an OAR, we generate adaptive margins that yield similar overall target coverage probability and reduced OAR dose-burden, at the expense of increased target volume. Three IMRT plans, using 3D margins and 2D per-beam margins with and without adaptation, were generated for five prostate patients with a prescription dose Dpres of 78Gy in 2Gy fractions using identical optimisation constraints. Systematic uncertainties of 1.1, 1.1, 1.5mm in the LR, SI, and AP directions, respectively, and 0.9, 1.1, 1.0mm for the random uncertainties, were assumed. A verification tool was employed to simulate the effects of systematic and random errors using a population size of 50,000. The fraction of the population that satisfies or violates a given DVH constraint was used for comparison. Results: We observe similar target coverage across all plans, with at least 97.5% of the population meeting the D98%>95%Dpres constraint. When looking at the probability of the population receiving D5<70Gy for the rectum, we observed median absolute increases of 23.61% (range, 2.15%–27.85%) and 6.97% (range, 0.65%–17.76%) using per-beam margins with and without adaptation, respectively, relative to using 3D margins. Conclusion: We observed sufficient and similar target coverage using per-beam margins. By adapting each per-beam margin away from an OAR, we can further reduce OAR dose without significantly

Ces-VP: consultation expert system for vector programming of nuclear codes

International Nuclear Information System (INIS)

Fujisaki, Masahide; Makino, Mitsuhiro; Ishiguro, Misako

1988-08-01

Ces-VP is a prototype rule-based expert system for consulting the vector programming, based on the knowledge of vectorization of nuclear codes at JAERI during these 10 years. Experts in vectorization can restructure nuclear codes with high performance on vector processors, since they have know-how for choosing the best technique among a lot of techniques that were acquired from the experience of vectorization in the past. Frequency in trial and error will be reduced if a beginner can easily use the know-how of experts. In this report, at first the contents of Ces-VP and its intention are shown. Then, the method for acquiring the know-how of vectorization and the method for making rules from the know-how are described. The outline of Ces-VP implemented on Fujitsu expert tool ESHELL is described. Finally, the availability of Ces-VP is evaluated from the data gathered from practical use and its present problems are discussed. (author)

Methods for Reducing Normal Tissue Complication Probabilities in Oropharyngeal Cancer: Dose Reduction or Planning Target Volume Elimination

Energy Technology Data Exchange (ETDEWEB)

Samuels, Stuart E.; Eisbruch, Avraham; Vineberg, Karen; Lee, Jae; Lee, Choonik; Matuszak, Martha M.; Ten Haken, Randall K.; Brock, Kristy K., E-mail: kbrock@med.umich.edu

2016-11-01

Purpose: Strategies to reduce the toxicities of head and neck radiation (ie, dysphagia [difficulty swallowing] and xerostomia [dry mouth]) are currently underway. However, the predicted benefit of dose and planning target volume (PTV) reduction strategies is unknown. The purpose of the present study was to compare the normal tissue complication probabilities (NTCP) for swallowing and salivary structures in standard plans (70 Gy [P70]), dose-reduced plans (60 Gy [P60]), and plans eliminating the PTV margin. Methods and Materials: A total of 38 oropharyngeal cancer (OPC) plans were analyzed. Standard organ-sparing volumetric modulated arc therapy plans (P70) were created and then modified by eliminating the PTVs and treating the clinical tumor volumes (CTVs) only (C70) or maintaining the PTV but reducing the dose to 60 Gy (P60). NTCP dose models for the pharyngeal constrictors, glottis/supraglottic larynx, parotid glands (PGs), and submandibular glands (SMGs) were analyzed. The minimal clinically important benefit was defined as a mean change in NTCP of >5%. The P70 NTCP thresholds and overlap percentages of the organs at risk with the PTVs (56-59 Gy, vPTV{sub 56}) were evaluated to identify the predictors for NTCP improvement. Results: With the P60 plans, only the ipsilateral PG (iPG) benefited (23.9% vs 16.2%; P<.01). With the C70 plans, only the iPG (23.9% vs 17.5%; P<.01) and contralateral SMG (cSMG) (NTCP 32.1% vs 22.9%; P<.01) benefited. An iPG NTCP threshold of 20% and 30% predicted NTCP benefits for the P60 and C70 plans, respectively (P<.001). A cSMG NTCP threshold of 30% predicted for an NTCP benefit with the C70 plans (P<.001). Furthermore, for the iPG, a vPTV{sub 56} >13% predicted benefit with P60 (P<.001) and C70 (P=.002). For the cSMG, a vPTV{sub 56} >22% predicted benefit with C70 (P<.01). Conclusions: PTV elimination and dose-reduction lowered the NTCP of the iPG, and PTV elimination lowered the NTCP of the cSMG. NTCP thresholds and the

X-ray vector radiography for bone micro-architecture diagnostics

Energy Technology Data Exchange (ETDEWEB)

Malecki, Andreas; Potdevin, Guillaume; Biernath, Thomas; Bech, Martin; Pfeiffer, Franz [Department of Physics and Institute of Medical Engineering, Technische Universitaet Muenchen, 85748 Garching (Germany)

2012-07-01

The non-invasive estimation of fracture risk in osteoporosis remains a challenge in the clinical routine and is mainly based on an assessment of bone density by dual X-ray absorption (DXA). Although bone micro-architecture is known to play an important role for bone fragility, its visualisation implies an imaging resolution better than 100 {mu}m, which limits the field of view and increases the necessary radiation dose. Here we describe a new method, X-ray Vector Radiography (XVR), based on X-ray scattering rather than absorption as contrast source, which yields information about the local orientation and degree of anisotropy of the bone micro-structure. This information is highly relevant for osteoporosis diagnostic. We demonstrate the feasibility by showing first experimental X-ray Vector Radiographies of human vertebra bone samples, yielding information on the trabecular structure.

Versatile generation of optical vector fields and vector beams using a non-interferometric approach.

Science.gov (United States)

Tripathi, Santosh; Toussaint, Kimani C

2012-05-07

We present a versatile, non-interferometric method for generating vector fields and vector beams which can produce all the states of polarization represented on a higher-order Poincaré sphere. The versatility and non-interferometric nature of this method is expected to enable exploration of various exotic properties of vector fields and vector beams. To illustrate this, we study the propagation properties of some vector fields and find that, in general, propagation alters both their intensity and polarization distribution, and more interestingly, converts some vector fields into vector beams. In the article, we also suggest a modified Jones vector formalism to represent vector fields and vector beams.

Image superresolution using support vector regression.

Science.gov (United States)

Ni, Karl S; Nguyen, Truong Q

2007-06-01

A thorough investigation of the application of support vector regression (SVR) to the superresolution problem is conducted through various frameworks. Prior to the study, the SVR problem is enhanced by finding the optimal kernel. This is done by formulating the kernel learning problem in SVR form as a convex optimization problem, specifically a semi-definite programming (SDP) problem. An additional constraint is added to reduce the SDP to a quadratically constrained quadratic programming (QCQP) problem. After this optimization, investigation of the relevancy of SVR to superresolution proceeds with the possibility of using a single and general support vector regression for all image content, and the results are impressive for small training sets. This idea is improved upon by observing structural properties in the discrete cosine transform (DCT) domain to aid in learning the regression. Further improvement involves a combination of classification and SVR-based techniques, extending works in resolution synthesis. This method, termed kernel resolution synthesis, uses specific regressors for isolated image content to describe the domain through a partitioned look of the vector space, thereby yielding good results.

Reduced dose uncertainty in MRI-based polymer gel dosimetry using parallel RF transmission with multiple RF sources

International Nuclear Information System (INIS)

Sang-Young Kim; Jung-Hoon Lee; Jin-Young Jung; Do-Wan Lee; Seu-Ran Lee; Bo-Young Choe; Hyeon-Man Baek; Korea University of Science and Technology, Daejeon; Dae-Hyun Kim; Jung-Whan Min; Ji-Yeon Park

2014-01-01

In this work, we present the feasibility of using a parallel RF transmit with multiple RF sources imaging method (MultiTransmit imaging) in polymer gel dosimetry. Image quality and B 1 field homogeneity was statistically better in the MultiTransmit imaging method than in conventional single source RF transmission imaging method. In particular, the standard uncertainty of R 2 was lower on the MultiTransmit images than on the conventional images. Furthermore, the MultiTransmit measurement showed improved dose resolution. Improved image quality and B 1 homogeneity results in reduced dose uncertainty, thereby suggesting the feasibility of MultiTransmit MR imaging in gel dosimetry. (author)

TU-G-204-09: The Effects of Reduced- Dose Lung Cancer Screening CT On Lung Nodule Detection Using a CAD Algorithm

Energy Technology Data Exchange (ETDEWEB)

Young, S; Lo, P; Kim, G; Hsu, W; Hoffman, J; Brown, M; McNitt-Gray, M [UCLA School of Medicine, Los Angeles, CA (United States)

2015-06-15

Purpose: While Lung Cancer Screening CT is being performed at low doses, the purpose of this study was to investigate the effects of further reducing dose on the performance of a CAD nodule-detection algorithm. Methods: We selected 50 cases from our local database of National Lung Screening Trial (NLST) patients for which we had both the image series and the raw CT data from the original scans. All scans were acquired with fixed mAs (25 for standard-sized patients, 40 for large patients) on a 64-slice scanner (Sensation 64, Siemens Healthcare). All images were reconstructed with 1-mm slice thickness, B50 kernel. 10 of the cases had at least one nodule reported on the NLST reader forms. Based on a previously-published technique, we added noise to the raw data to simulate reduced-dose versions of each case at 50% and 25% of the original NLST dose (i.e. approximately 1.0 and 0.5 mGy CTDIvol). For each case at each dose level, the CAD detection algorithm was run and nodules greater than 4 mm in diameter were reported. These CAD results were compared to “truth”, defined as the approximate nodule centroids from the NLST reports. Subject-level mean sensitivities and false-positive rates were calculated for each dose level. Results: The mean sensitivities of the CAD algorithm were 35% at the original dose, 20% at 50% dose, and 42.5% at 25% dose. The false-positive rates, in decreasing-dose order, were 3.7, 2.9, and 10 per case. In certain cases, particularly in larger patients, there were severe photon-starvation artifacts, especially in the apical region due to the high-attenuating shoulders. Conclusion: The detection task was challenging for the CAD algorithm at all dose levels, including the original NLST dose. However, the false-positive rate at 25% dose approximately tripled, suggesting a loss of CAD robustness somewhere between 0.5 and 1.0 mGy. NCI grant U01 CA181156 (Quantitative Imaging Network); Tobacco Related Disease Research Project grant 22RT-0131.

TU-G-204-09: The Effects of Reduced- Dose Lung Cancer Screening CT On Lung Nodule Detection Using a CAD Algorithm

International Nuclear Information System (INIS)

Young, S; Lo, P; Kim, G; Hsu, W; Hoffman, J; Brown, M; McNitt-Gray, M

2015-01-01

Purpose: While Lung Cancer Screening CT is being performed at low doses, the purpose of this study was to investigate the effects of further reducing dose on the performance of a CAD nodule-detection algorithm. Methods: We selected 50 cases from our local database of National Lung Screening Trial (NLST) patients for which we had both the image series and the raw CT data from the original scans. All scans were acquired with fixed mAs (25 for standard-sized patients, 40 for large patients) on a 64-slice scanner (Sensation 64, Siemens Healthcare). All images were reconstructed with 1-mm slice thickness, B50 kernel. 10 of the cases had at least one nodule reported on the NLST reader forms. Based on a previously-published technique, we added noise to the raw data to simulate reduced-dose versions of each case at 50% and 25% of the original NLST dose (i.e. approximately 1.0 and 0.5 mGy CTDIvol). For each case at each dose level, the CAD detection algorithm was run and nodules greater than 4 mm in diameter were reported. These CAD results were compared to “truth”, defined as the approximate nodule centroids from the NLST reports. Subject-level mean sensitivities and false-positive rates were calculated for each dose level. Results: The mean sensitivities of the CAD algorithm were 35% at the original dose, 20% at 50% dose, and 42.5% at 25% dose. The false-positive rates, in decreasing-dose order, were 3.7, 2.9, and 10 per case. In certain cases, particularly in larger patients, there were severe photon-starvation artifacts, especially in the apical region due to the high-attenuating shoulders. Conclusion: The detection task was challenging for the CAD algorithm at all dose levels, including the original NLST dose. However, the false-positive rate at 25% dose approximately tripled, suggesting a loss of CAD robustness somewhere between 0.5 and 1.0 mGy. NCI grant U01 CA181156 (Quantitative Imaging Network); Tobacco Related Disease Research Project grant 22RT-0131

Eco-friendly control of malaria and arbovirus vectors using the mosquitofish Gambusia affinis and ultra-low dosages of Mimusops elengi-synthesized silver nanoparticles: towards an integrative approach?

Science.gov (United States)

Subramaniam, Jayapal; Murugan, Kadarkarai; Panneerselvam, Chellasamy; Kovendan, Kalimuthu; Madhiyazhagan, Pari; Kumar, Palanisamy Mahesh; Dinesh, Devakumar; Chandramohan, Balamurugan; Suresh, Udaiyan; Nicoletti, Marcello; Higuchi, Akon; Hwang, Jiang-Shiou; Kumar, Suresh; Alarfaj, Abdullah A; Munusamy, Murugan A; Messing, Russell H; Benelli, Giovanni

2015-12-01

Mosquito-borne diseases represent a deadly threat for millions of people worldwide. However, the use of synthetic insecticides to control Culicidae may lead to high operational costs and adverse non-target effects. Plant-borne compounds have been proposed for rapid extracellular synthesis of mosquitocidal nanoparticles. Their impact against biological control agents of mosquito larval populations has been poorly studied. We synthesized silver nanoparticles (AgNP) using the aqueous leaf extract of Mimusops elengi as a reducing and stabilizing agent. The formation of AgNP was studied using different biophysical methods, including UV-vis spectrophotometry, TEM, XRD, EDX and FTIR. Low doses of AgNP showed larvicidal and pupicidal toxicity against the malaria vector Anopheles stephensi and the arbovirus vector Aedes albopictus. AgNP LC50 against A. stephensi ranged from 12.53 (I instar larvae) to 23.55 ppm (pupae); LC50 against A. albopictus ranged from 11.72 ppm (I) to 21.46 ppm (pupae). In the field, the application of M. elengi extract and AgNP (10 × LC50) led to 100 % larval reduction after 72 h. In adulticidal experiments, AgNP showed LC50 of 13.7 ppm for A. stephensi and 14.7 ppm for A. albopictus. The predation efficiency of Gambusia affinis against A. stephensi and A. albopictus III instar larvae was 86.2 and 81.7 %, respectively. In AgNP-contaminated environments, predation was 93.7 and 88.6 %, respectively. This research demonstrates that M. elengi-synthesized AgNP may be employed at ultra-low doses to reduce larval populations of malaria and arbovirus vectors, without detrimental effects on predation rates of mosquito natural enemies, such as larvivorous fishes.

Vectorized Monte Carlo

International Nuclear Information System (INIS)

Brown, F.B.

1981-01-01

Examination of the global algorithms and local kernels of conventional general-purpose Monte Carlo codes shows that multigroup Monte Carlo methods have sufficient structure to permit efficient vectorization. A structured multigroup Monte Carlo algorithm for vector computers is developed in which many particle events are treated at once on a cell-by-cell basis. Vectorization of kernels for tracking and variance reduction is described, and a new method for discrete sampling is developed to facilitate the vectorization of collision analysis. To demonstrate the potential of the new method, a vectorized Monte Carlo code for multigroup radiation transport analysis was developed. This code incorporates many features of conventional general-purpose production codes, including general geometry, splitting and Russian roulette, survival biasing, variance estimation via batching, a number of cutoffs, and generalized tallies of collision, tracklength, and surface crossing estimators with response functions. Predictions of vectorized performance characteristics for the CYBER-205 were made using emulated coding and a dynamic model of vector instruction timing. Computation rates were examined for a variety of test problems to determine sensitivities to batch size and vector lengths. Significant speedups are predicted for even a few hundred particles per batch, and asymptotic speedups by about 40 over equivalent Amdahl 470V/8 scalar codes arepredicted for a few thousand particles per batch. The principal conclusion is that vectorization of a general-purpose multigroup Monte Carlo code is well worth the significant effort required for stylized coding and major algorithmic changes

Low tube voltage dual source computed tomography to reduce contrast media doses in adult abdomen examinations: A phantom study

Energy Technology Data Exchange (ETDEWEB)

Thor, Daniel [Department of Diagnostic Medical Physics, Karolinska University Hospital, Stockholm 14186 (Sweden); Brismar, Torkel B., E-mail: torkel.brismar@gmail.com; Fischer, Michael A. [Department of Clinical Science, Intervention and Technology at Karolinska Institutet and Department of Radiology, Karolinska University Hospital in Huddinge, Stockholm 14186 (Sweden)

2015-09-15

Purpose: To evaluate the potential of low tube voltage dual source (DS) single energy (SE) and dual energy (DE) computed tomography (CT) to reduce contrast media (CM) dose in adult abdominal examinations of various sizes while maintaining soft tissue and iodine contrast-to-noise ratio (CNR). Methods: Four abdominal phantoms simulating a body mass index of 16 to 35 kg/m{sup 2} with four inserted syringes of 0, 2, 4, and 8 mgI/ml CM were scanned using a 64-slice DS-CT scanner. Six imaging protocols were used; one single source (SS) reference protocol (120 kV, 180 reference mAs), four low kV SE protocols (70 and 80 kV using both SS and DS), and one DE protocol at 80/140 kV. Potential CM reduction with unchanged CNRs relative to the 120 kV protocol was calculated along with the corresponding increase in radiation dose. Results: The potential contrast media reductions were determined to be approximately 53% for DS 70 kV, 51% for SS 70 kV, 44% for DS 80 kV, 40% for SS 80 kV, and 20% for DE (all differences were significant, P < 0.05). Constant CNR could be achieved by using DS 70 kV for small to medium phantom sizes (16–26 kg/m{sup 2}) and for all sizes (16–35 kg/m{sup 2}) when using DS 80 kV and DE. Corresponding radiation doses increased by 60%–107%, 23%–83%, and 6%–12%, respectively. Conclusions: DS single energy CT can be used to reduce CM dose by 44%–53% with maintained CNR in adult abdominal examinations at the cost of an increased radiation dose. DS dual-energy CT allows reduction of CM dose by 20% at similar radiation dose as compared to a standard 120 kV single source.

Vector Network Coding

OpenAIRE

Ebrahimi, Javad; Fragouli, Christina

2010-01-01

We develop new algebraic algorithms for scalar and vector network coding. In vector network coding, the source multicasts information by transmitting vectors of length L, while intermediate nodes process and combine their incoming packets by multiplying them with L X L coding matrices that play a similar role as coding coefficients in scalar coding. Our algorithms for scalar network jointly optimize the employed field size while selecting the coding coefficients. Similarly, for vector co...

Vector independent transmission of the vector-borne bluetongue virus.

Science.gov (United States)

van der Sluijs, Mirjam Tineke Willemijn; de Smit, Abraham J; Moormann, Rob J M

2016-01-01

Bluetongue is an economically important disease of ruminants. The causative agent, Bluetongue virus (BTV), is mainly transmitted by insect vectors. This review focuses on vector-free BTV transmission, and its epizootic and economic consequences. Vector-free transmission can either be vertical, from dam to fetus, or horizontal via direct contract. For several BTV-serotypes, vertical (transplacental) transmission has been described, resulting in severe congenital malformations. Transplacental transmission had been mainly associated with live vaccine strains. Yet, the European BTV-8 strain demonstrated a high incidence of transplacental transmission in natural circumstances. The relevance of transplacental transmission for the epizootiology is considered limited, especially in enzootic areas. However, transplacental transmission can have a substantial economic impact due to the loss of progeny. Inactivated vaccines have demonstrated to prevent transplacental transmission. Vector-free horizontal transmission has also been demonstrated. Since direct horizontal transmission requires close contact of animals, it is considered only relevant for within-farm spreading of BTV. The genetic determinants which enable vector-free transmission are present in virus strains circulating in the field. More research into the genetic changes which enable vector-free transmission is essential to better evaluate the risks associated with outbreaks of new BTV serotypes and to design more appropriate control measures.

Organ dose and effective dose with the EOS scanner in spine deformity surgery

DEFF Research Database (Denmark)

Heide Pedersen, Peter; Petersen, Asger Greval; Eiskjær, Søren Peter

2016-01-01

Organ dose and effective dose with the EOS scanner in spine deformity surgery. A study on anthropomorphic phantoms describing patient radiation exposure in full spine examinations. Authors: Peter Heide Pedersen, Asger Greval Petersen, Søren Peter Eiskjær. Background: Ionizing radiation potentially...... quality images while at the same time reducing radiation dose. At our institution we use the EOS for pre- and postoperative full spine examinations. Purpose: The purpose of the study is to make first time organ dose and effective dose evaluations with micro-dose settings in full spine examinations. Our...... hypothesis is that organ dose and effective doses can be reduced 5-10 times compared to standard settings, without too high image-quality trade off, resulting in a theoretical reduction of radiation induced cancer. Methods: Patient dosimetry is performed on anthropomorphic child phantoms, representing a 5...

Development of oral CTL vaccine using a CTP-integrated Sabin 1 poliovirus-based vector system.

Science.gov (United States)

Han, Seung-Soo; Lee, Jinjoo; Jung, Yideul; Kang, Myeong-Ho; Hong, Jung-Hyub; Cha, Min-Suk; Park, Yu-Jin; Lee, Ezra; Yoon, Cheol-Hee; Bae, Yong-Soo

2015-09-11

We developed a CTL vaccine vector by modification of the RPS-Vax system, a mucosal vaccine vector derived from a poliovirus Sabin 1 strain, and generated an oral CTL vaccine against HIV-1. A DNA fragment encoding a cytoplasmic transduction peptide (CTP) was integrated into the RPS-Vax system to generate RPS-CTP, a CTL vaccine vector. An HIV-1 p24 cDNA fragment was introduced into the RPS-CTP vector system and a recombinant poliovirus (rec-PV) named vRPS-CTP/p24 was produced. vRPS-CTP/p24 was genetically stable and efficiently induced Th1 immunity and p24-specific CTLs in immunized poliovirus receptor-transgenic (PVR-Tg) mice. In challenge experiments, PVR-Tg mice that were pre-immunized orally with vRPS-CTP/p24 were resistant to challenge with a lethal dose of p24-expressing recombinant vaccinia virus (rMVA-p24). These results suggested that the RPS-CTP vector system had potential for developing oral CTL vaccines against infectious diseases. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Kalman Filter for SINS Self-Alignment Based on Vector Observation.

Science.gov (United States)

Xu, Xiang; Xu, Xiaosu; Zhang, Tao; Li, Yao; Tong, Jinwu

2017-01-29

In this paper, a self-alignment method for strapdown inertial navigation systems based on the q -method is studied. In addition, an improved method based on integrating gravitational apparent motion to form apparent velocity is designed, which can reduce the random noises of the observation vectors. For further analysis, a novel self-alignment method using a Kalman filter based on adaptive filter technology is proposed, which transforms the self-alignment procedure into an attitude estimation using the observation vectors. In the proposed method, a linear psuedo-measurement equation is adopted by employing the transfer method between the quaternion and the observation vectors. Analysis and simulation indicate that the accuracy of the self-alignment is improved. Meanwhile, to improve the convergence rate of the proposed method, a new method based on parameter recognition and a reconstruction algorithm for apparent gravitation is devised, which can reduce the influence of the random noises of the observation vectors. Simulations and turntable tests are carried out, and the results indicate that the proposed method can acquire sound alignment results with lower standard variances, and can obtain higher alignment accuracy and a faster convergence rate.

Genetic shifting: a novel approach for controlling vector-borne diseases

OpenAIRE

Powell, Jeffrey R.; Tabachnick, Walter J.

2014-01-01

Rendering populations of vectors of diseases incapable of transmitting pathogens through genetic methods has long been a goal of vector geneticists. We outline a method to achieve this goal that does not involve introduction of any new genetic variants to the target population. Rather we propose that shifting the frequencies of naturally occurring alleles that confer refractoriness to transmission can reduce transmission below a sustainable level. The program employs methods successfully used...

Dose-Volume Constraints to Reduce Rectal Side Effects From Prostate Radiotherapy: Evidence From MRC RT01 Trial ISRCTN 47772397

International Nuclear Information System (INIS)

Gulliford, Sarah L.; Foo, Kerwyn; Morgan, Rachel C.; Aird, Edwin G.; Bidmead, A. Margaret; Critchley, Helen; Evans, Philip M. D.Phil.; Gianolini, Stefano; Mayles, W. Philip; Moore, A. Rollo; Sanchez-Nieto, Beatriz; Partridge, Mike; Sydes, Matthew R. C.Stat; Webb, Steve; Dearnaley, David P.

2010-01-01

Purpose: Radical radiotherapy for prostate cancer is effective but dose limited because of the proximity of normal tissues. Comprehensive dose-volume analysis of the incidence of clinically relevant late rectal toxicities could indicate how the dose to the rectum should be constrained. Previous emphasis has been on constraining the mid-to-high dose range (≥50 Gy). Evidence is emerging that lower doses could also be important. Methods and Materials: Data from a large multicenter randomized trial were used to investigate the correlation between seven clinically relevant rectal toxicity endpoints (including patient- and clinician-reported outcomes) and an absolute 5% increase in the volume of rectum receiving the specified doses. The results were quantified using odds ratios. Rectal dose-volume constraints were applied retrospectively to investigate the association of constraints with the incidence of late rectal toxicity. Results: A statistically significant dose-volume response was observed for six of the seven endpoints for at least one of the dose levels tested in the range of 30-70 Gy. Statistically significant reductions in the incidence of these late rectal toxicities were observed for the group of patients whose treatment plans met specific proposed dose-volume constraints. The incidence of moderate/severe toxicity (any endpoint) decreased incrementally for patients whose treatment plans met increasing numbers of dose-volume constraints from the set of V30≤80%, V40≤65%, V50≤55%, V60≤40%, V65≤30%, V70≤15%, and V75≤3%. Conclusion: Considering the entire dose distribution to the rectum by applying dose-volume constraints such as those tested here in the present will reduce the incidence of late rectal toxicity.

VectorBase

Data.gov (United States)

U.S. Department of Health & Human Services — VectorBase is a Bioinformatics Resource Center for invertebrate vectors. It is one of four Bioinformatics Resource Centers funded by NIAID to provide web-based...

Custodial vector model

DEFF Research Database (Denmark)

Becciolini, Diego; Franzosi, Diogo Buarque; Foadi, Roshan

2015-01-01

We analyze the Large Hadron Collider (LHC) phenomenology of heavy vector resonances with a $SU(2)_L\\times SU(2)_R$ spectral global symmetry. This symmetry partially protects the electroweak S-parameter from large contributions of the vector resonances. The resulting custodial vector model spectrum...

Use of remifentanil to reduce propofol injection pain and the required propofol dose in upper digestive tract endoscopy diagnostic tests.

Science.gov (United States)

Uliana, Gustavo Nadal; Tambara, Elizabeth Milla; Baretta, Giorgio Alfredo Pedroso

2015-01-01

The introduction of propofol (2,6-diisopropylphenol) as a sedative agent has transformed the area of sedation for endoscopic procedures. However, a major drawback of sedation with the use of propofol is its high incidence of injection pain. The most widely used technique in reducing propofol injection pain is through the association of other drugs. The aim of this study was to evaluate the effect of remifentanil-propofol combination on the incidence of propofol injection pain and its influence on the total dose of propofol required for sedation in upper digestive tract endoscopy (UDE) diagnostic tests. One hundred and five patients undergoing upper digestive tract endoscopy were evaluated and randomly divided into 3 groups of 35 patients each. The Control Group received propofol alone; Study-group 1 received remifentanil at a fixed dose of 0.2mg/kg combined with propofol; Study-group 2 received remifentanil at a fixed dose of 0.3mg/kg combined with propofol. The incidence of propofol injection pain and the total dose of propofol required for the test were evaluated. The sample was very similar regarding age, weight, height, sex, and physical status. Statistical analysis was performed according to the nature of the evaluated data. Student's t-test was used to compare the mean of age, weight, height (cm), and dose (mg/kg) variables between groups. The χ(2) test was used to compare sex, physical status, and propofol injection pain between groups. The significance level was αpain and total dose of propofol (mg/kg) used. However, there were no statistical differences between the two study groups for these parameters. We conclude that the use of remifentanil at doses of 0.2mg/kg and 0.3mg/kg was effective for reducing both the propofol injection pain and the total dose of propofol used. Copyright © 2015 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

DNA Minicircle Technology Improves Purity of Adeno-associated Viral Vector Preparations

Directory of Open Access Journals (Sweden)

Maria Schnödt

2016-01-01

Full Text Available Adeno-associated viral (AAV vectors are considered as one of the most promising delivery systems in human gene therapy. In addition, AAV vectors are frequently applied tools in preclinical and basic research. Despite this success, manufacturing pure AAV vector preparations remains a difficult task. While empty capsids can be removed from vector preparations owing to their lower density, state-of-the-art purification strategies as of yet failed to remove antibiotic resistance genes or other plasmid backbone sequences. Here, we report the development of minicircle (MC constructs to replace AAV vector and helper plasmids for production of both, single-stranded (ss and self-complementary (sc AAV vectors. As bacterial backbone sequences are removed during MC production, encapsidation of prokaryotic plasmid backbone sequences is avoided. This is of particular importance for scAAV vector preparations, which contained an unproportionally high amount of plasmid backbone sequences (up to 26.1% versus up to 2.9% (ssAAV. Replacing standard packaging plasmids by MC constructs not only allowed to reduce these contaminations below quantification limit, but in addition improved transduction efficiencies of scAAV preparations up to 30-fold. Thus, MC technology offers an easy to implement modification of standard AAV packaging protocols that significantly improves the quality of AAV vector preparations.

Experimental demonstration of vector E x vector B plasma divertor

International Nuclear Information System (INIS)

Strait, E.J.; Kerst, D.W.; Sprott, J.C.

1977-01-01

The vector E x vector B drift due to an applied radial electric field in a tokamak with poloidal divertor can speed the flow of plasma out of the scrape-off region, and provide a means of externally controlling the flow rate and thus the width of the density fall-off. An experiment in the Wisconsin levitated toroidal octupole, using vector E x vector B drifts alone, demonstrates divertor-like behavior, including 70% reduction of plasma density near the wall and 40% reduction of plasma flux to the wall, with no adverse effects on confinement of the main plasma

SU-G-BRC-15: The Potential Clinical Significance of Dose Mapping Error for Intra- Fraction Dose Mapping for Lung Cancer Patients

Energy Technology Data Exchange (ETDEWEB)

Sayah, N [Thomas Cancer Center, Richmond, VA (United States); Weiss, E [Virginia Commonwealth University, Richmond, Virginia (United States); Watkins, W [University of Virginia, Charlottesville, VA (United States); Siebers, J [University of Virginia Health System, Charlottesville, VA (United States)

2016-06-15

Purpose: To evaluate the dose-mapping error (DME) inherent to conventional dose-mapping algorithms as a function of dose-matrix resolution. Methods: As DME has been reported to be greatest where dose-gradients overlap tissue-density gradients, non-clinical 66 Gy IMRT plans were generated for 11 lung patients with the target edge defined as the maximum 3D density gradient on the 0% (end of inhale) breathing phase. Post-optimization, Beams were copied to 9 breathing phases. Monte Carlo dose computed (with 2*2*2 mm{sup 3} resolution) on all 10 breathing phases was deformably mapped to phase 0% using the Monte Carlo energy-transfer method with congruent mass-mapping (EMCM); an externally implemented tri-linear interpolation method with voxel sub-division; Pinnacle’s internal (tri-linear) method; and a post-processing energy-mass voxel-warping method (dTransform). All methods used the same base displacement-vector-field (or it’s pseudo-inverse as appropriate) for the dose mapping. Mapping was also performed at 4*4*4 mm{sup 3} by merging adjacent dose voxels. Results: Using EMCM as the reference standard, no clinically significant (>1 Gy) DMEs were found for the mean lung dose (MLD), lung V20Gy, or esophagus dose-volume indices, although MLD and V20Gy were statistically different (2*2*2 mm{sup 3}). Pinnacle-to-EMCM target D98% DMEs of 4.4 and 1.2 Gy were observed ( 2*2*2 mm{sup 3}). However dTransform, which like EMCM conserves integral dose, had DME >1 Gy for one case. The root mean square RMS of the DME for the tri-linear-to- EMCM methods was lower for the smaller voxel volume for the tumor 4D-D98%, lung V20Gy, and cord D1%. Conclusion: When tissue gradients overlap with dose gradients, organs-at-risk DME was statistically significant but not clinically significant. Target-D98%-DME was deemed clinically significant for 2/11 patients (2*2*2 mm{sup 3}). Since tri-linear RMS-DME between EMCM and tri-linear was reduced at 2*2*2 mm{sup 3}, use of this resolution is

A NEW METHOD TO QUANTIFY AND REDUCE THE NET PROJECTION ERROR IN WHOLE-SOLAR-ACTIVE-REGION PARAMETERS MEASURED FROM VECTOR MAGNETOGRAMS

Energy Technology Data Exchange (ETDEWEB)

Falconer, David A.; Tiwari, Sanjiv K.; Moore, Ronald L. [NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States); Khazanov, Igor, E-mail: David.a.Falconer@nasa.gov [Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

2016-12-20

Projection errors limit the use of vector magnetograms of active regions (ARs) far from the disk center. In this Letter, for ARs observed up to 60° from the disk center, we demonstrate a method for measuring and reducing the projection error in the magnitude of any whole-AR parameter that is derived from a vector magnetogram that has been deprojected to the disk center. The method assumes that the center-to-limb curve of the average of the parameter’s absolute values, measured from the disk passage of a large number of ARs and normalized to each AR’s absolute value of the parameter at central meridian, gives the average fractional projection error at each radial distance from the disk center. To demonstrate the method, we use a large set of large-flux ARs and apply the method to a whole-AR parameter that is among the simplest to measure: whole-AR magnetic flux. We measure 30,845 SDO /Helioseismic and Magnetic Imager vector magnetograms covering the disk passage of 272 large-flux ARs, each having whole-AR flux >10{sup 22} Mx. We obtain the center-to-limb radial-distance run of the average projection error in measured whole-AR flux from a Chebyshev fit to the radial-distance plot of the 30,845 normalized measured values. The average projection error in the measured whole-AR flux of an AR at a given radial distance is removed by multiplying the measured flux by the correction factor given by the fit. The correction is important for both the study of the evolution of ARs and for improving the accuracy of forecasts of an AR’s major flare/coronal mass ejection productivity.

CellSort: a support vector machine tool for optimizing fluorescence-activated cell sorting and reducing experimental effort.

Science.gov (United States)

Yu, Jessica S; Pertusi, Dante A; Adeniran, Adebola V; Tyo, Keith E J

2017-03-15

High throughput screening by fluorescence activated cell sorting (FACS) is a common task in protein engineering and directed evolution. It can also be a rate-limiting step if high false positive or negative rates necessitate multiple rounds of enrichment. Current FACS software requires the user to define sorting gates by intuition and is practically limited to two dimensions. In cases when multiple rounds of enrichment are required, the software cannot forecast the enrichment effort required. We have developed CellSort, a support vector machine (SVM) algorithm that identifies optimal sorting gates based on machine learning using positive and negative control populations. CellSort can take advantage of more than two dimensions to enhance the ability to distinguish between populations. We also present a Bayesian approach to predict the number of sorting rounds required to enrich a population from a given library size. This Bayesian approach allowed us to determine strategies for biasing the sorting gates in order to reduce the required number of enrichment rounds. This algorithm should be generally useful for improve sorting outcomes and reducing effort when using FACS. Source code available at http://tyolab.northwestern.edu/tools/ . k-tyo@northwestern.edu. Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

Rotations with Rodrigues' vector

International Nuclear Information System (INIS)

Pina, E

2011-01-01

The rotational dynamics was studied from the point of view of Rodrigues' vector. This vector is defined here by its connection with other forms of parametrization of the rotation matrix. The rotation matrix was expressed in terms of this vector. The angular velocity was computed using the components of Rodrigues' vector as coordinates. It appears to be a fundamental matrix that is used to express the components of the angular velocity, the rotation matrix and the angular momentum vector. The Hamiltonian formalism of rotational dynamics in terms of this vector uses the same matrix. The quantization of the rotational dynamics is performed with simple rules if one uses Rodrigues' vector and similar formal expressions for the quantum operators that mimic the Hamiltonian classical dynamics.

Dose-response study of the hematological toxicity induced by vectorized radionuclides in a mouse model

International Nuclear Information System (INIS)

Rousseau-Poivet, J.; Sas, N.; Nguyen, F.; Abadie, J.; Chouin, N.; Barbet, J.

2015-01-01

Full text of publication follows. Aim: in internal radiotherapy, the dose-limiting factor is often the bone marrow (BM) toxicity. In patients, its relationship with the BM absorbed dose seems to be elusive. Most probable reasons are the BM depletion following previous treatments associated to dose assessment complexity. To avoid this and better understand myelotoxicity mechanisms, we investigated hematopoiesis from BM to blood after radionuclide injections in healthy mice associated to individual BM dosimetry. Based on these data, a compartmental model was developed to predict the depletion of each mouse hematopoietic cell in a dose-dependent manner. Materials and methods: C57/Bl6 mice were injected with increasing activities of 18 FNa, an osteo-tropic agent. Mean absorbed doses to the BM were calculated using the MIRD formalism with the mineralized bone considered as the principal source of 18 FNa. Time-integrated activities within the skeleton were derived from dynamic micro PET-CT images. Hematological toxicity was monitored via blood cell counts and myeloid progenitor colony assays over time after injection. The myelotoxicity model consists in compartments for each hematopoietic cell. Its parameters were adjusted to reproduce experimental toxicities. Results: for an absorbed dose to the BM of 0.8 ± 0.1 Gy, myeloid progenitors showed a 84% depletion 84% at day 7 post-injection (D7) and a recovery at D14 for all precursors and D21 for the less differentiated progenitor. In blood, neutrocytopenia was observed at D3 (80% decrease) and recovered at D7. Thrombocytopenia was also noticed between D7 and D17 with a nadir at D7 (26% of depletion). The compartmental model predicted platelets kinetics in a satisfying manner. The nadir value, time to nadir and time to recovery were estimated with errors of 4.9%, 10.2% and 10% respectively. Whereas higher absorbed doses only increased platelets depletion (62% associated to 1.4 Gy), they extended the recovery time for all

Canine and feline vector-borne diseases in Italy: current situation and perspectives

Directory of Open Access Journals (Sweden)

Dantas-Torres Filipe

2010-01-01

Full Text Available Abstract In Italy, dogs and cats are at risk of becoming infected by different vector-borne pathogens, including protozoa, bacteria, and helminths. Ticks, fleas, phlebotomine sand flies, and mosquitoes are recognized vectors of pathogens affecting cats and dogs, some of which (e.g., Anaplasma phagocytophilum, Borrelia burgdorferi, Dipylidium caninum, Leishmania infantum, Dirofilaria immitis, and Dirofilaria repens are of zoonotic concern. Recent studies have highlighted the potential of fleas as vectors of pathogens of zoonotic relevance (e.g., Rickettsia felis in this country. While some arthropod vectors (e.g., ticks and fleas are present in certain Italian regions throughout the year, others (e.g., phlebotomine sand flies are most active during the summer season. Accordingly, control strategies, such as those relying on the systematic use of acaricides and insecticides, should be planned on the basis of the ecology of both vectors and pathogens in different geographical areas in order to improve their effectiveness in reducing the risk of infection by vector-borne pathogens. This article reviews the current situation and perspectives of canine and feline vector-borne diseases in Italy.

Violation of vector dominance in the vector manifestation

International Nuclear Information System (INIS)

Sasaki, Chihiro

2003-01-01

The vector manifestation (VM) is a new pattern for realizing the chiral symmetry in QCD. In the VM, the massless vector meson becomes the chiral partner of pion at the critical point, in contrast with the restoration based on the linear sigma model. Including the intrinsic temperature dependences of the parameters of the hidden local symmetry (HLS) Lagrangian determined from the underlying QCD through the Wilsonian matching together with the hadronic thermal corrections, we present a new prediction of the VM on the direct photon-π-π coupling which measures the validity of the vector dominance (VD) of the electromagnetic form factor of the pion. We find that the VD is largely violated at the critical temperature, which indicates that the assumption of the VD made in several analysis on the dilepton spectra in hot matter may need to be weakened for consistently including the effect of the dropping mass of the vector meson. (author)

The standardised freight container: vector of vectors and vector-borne diseases.

Science.gov (United States)

Reiter, P

2010-04-01

The standardised freight container was one of the most important innovations of the 20th Century. Containerised cargoes travel from their point of origin to their destination by ship, road and rail as part of a single journey, without unpacking. This simple concept is the key element in cheap, rapid transport by land and sea, and has led to a phenomenal growth in global trade. Likewise, containerised air cargo has led to a remarkable increase in the inter-continental transportation of goods, particularly perishable items such as flowers, fresh vegetables and live animals. In both cases, containerisation offers great advantages in speed and security, but reduces the opportunity to inspect cargoes in transit. An inevitable consequence is the globalisation of undesirable species of animals, plants and pathogens. Moreover, cheap passenger flights offer worldwide travel for viral and parasitic pathogens in infected humans. The continued emergence of exotic pests, vectors and pathogens throughout the world is an unavoidable consequence of these advances in transportation technology.

Adenovirus dodecahedron, as a drug delivery vector.

Directory of Open Access Journals (Sweden)

Monika Zochowska

Full Text Available BACKGROUND: Bleomycin (BLM is an anticancer antibiotic used in many cancer regimens. Its utility is limited by systemic toxicity and dose-dependent pneumonitis able to progress to lung fibrosis. The latter can affect up to nearly 50% of the total patient population, out of which 3% will die. We propose to improve BLM delivery by tethering it to an efficient delivery vector. Adenovirus (Ad dodecahedron base (DB is a particulate vector composed of 12 copies of a pentameric viral protein responsible for virus penetration. The vector efficiently penetrates the plasma membrane, is liberated in the cytoplasm and has a propensity to concentrate around the nucleus; up to 300000 particles can be observed in one cell in vitro. PRINCIPAL FINDINGS: Dodecahedron (Dd structure is preserved at up to about 50 degrees C at pH 7-8 and during dialysis, freezing and drying in the speed-vac in the presence of 150 mM ammonium sulfate, as well as during lyophilization in the presence of cryoprotectants. The vector is also stable in human serum for 2 h at 37 degrees C. We prepared a Dd-BLM conjugate which upon penetration induced death of transformed cells. Similarly to free bleomycin, Dd-BLM caused dsDNA breaks. Significantly, effective cytotoxic concentration of BLM delivered with Dd was 100 times lower than that of free bleomycin. CONCLUSIONS/SIGNIFICANCE: Stability studies show that Dds can be conveniently stored and transported, and can potentially be used for therapeutic purposes under various climates. Successful BLM delivery by Ad Dds demonstrates that the use of virus like particle (VLP results in significantly improved drug bioavailability. These experiments open new vistas for delivery of non-permeant labile drugs.

Reconfigurable support vector machine classifier with approximate computing

NARCIS (Netherlands)

van Leussen, M.J.; Huisken, J.; Wang, L.; Jiao, H.; De Gyvez, J.P.

2017-01-01

Support Vector Machine (SVM) is one of the most popular machine learning algorithms. An energy-efficient SVM classifier is proposed in this paper, where approximate computing is utilized to reduce energy consumption and silicon area. A hardware architecture with reconfigurable kernels and

Simplified lentivirus vector production in protein-free media using polyethylenimine-mediated transfection.

Science.gov (United States)

Kuroda, Hitoshi; Kutner, Robert H; Bazan, Nicolas G; Reiser, Jakob

2009-05-01

During the past 12 years, lentiviral vectors have emerged as valuable tools for transgene delivery because of their ability to transduce nondividing cells and their capacity to sustain long-term transgene expression. Despite significant progress, the production of high-titer high-quality lentiviral vectors is cumbersome and costly. The most commonly used method to produce lentiviral vectors involves transient transfection using calcium phosphate (CaP)-mediated precipitation of plasmid DNAs. However, inconsistencies in pH can cause significant batch-to-batch variations in lentiviral vector titers, making this method unreliable. This study describes optimized protocols for lentiviral vector production based on polyethylenimine (PEI)-mediated transfection, resulting in more consistent lentiviral vector stocks. To achieve this goal, simple production methods for high-titer lentiviral vector production involving transfection of HEK 293T cells immediately after plating were developed. Importantly, high titers were obtained with cell culture media lacking serum or other protein additives altogether. As a consequence, large-scale lentiviral vector stocks can now be generated with fewer batch-to-batch variations and at reduced costs and with less labor compared to the standard protocols.

Vector-borne disease risk indexes in spatially structured populations.

Directory of Open Access Journals (Sweden)

Jorge Velázquez-Castro

2018-02-01

Full Text Available There are economic and physical limitations when applying prevention and control strategies for urban vector borne diseases. Consequently, there are increasing concerns and interest in designing efficient strategies and regulations that health agencies can follow in order to reduce the imminent impact of viruses like Dengue, Zika and Chikungunya. That includes fumigation, abatization, reducing the hatcheries, picking up trash, information campaigns. A basic question that arise when designing control strategies is about which and where these ones should focus. In other words, one would like to know whether preventing the contagion or decrease vector population, and in which area of the city, is more efficient. In this work, we propose risk indexes based on the idea of secondary cases from patch to patch. Thus, they take into account human mobility and indicate which patch has more chance to be a corridor for the spread of the disease and which is more vulnerable, i.e. more likely to have cases?. They can also indicate the neighborhood where hatchery control will reduce more the number of potential cases. In order to illustrate the usefulness of these indexes, we run a set of numerical simulations in a mathematical model that takes into account the urban mobility and the differences in population density among the areas of a city. If we label by i a particular neighborhood, the transmission risk index (TRi measures the potential secondary cases caused by a host in that neighborhood. The vector transmission risk index (VTRi measures the potential secondary cases caused by a vector. Finally, the vulnerability risk index (VRi measures the potential secondary cases in the neighborhood. Transmission indexes can be used to give geographical priority to some neighborhoods when applying prevention and control measures. On the other hand, the vulnerability index can be useful to implement monitoring campaigns or public health investment.

Interference in Exclusive Vector Meson Production in Heavy-Ion Collisions

International Nuclear Information System (INIS)

Klein, Spencer R.; Nystrand, Joakim

2000-01-01

Vector mesons are produced copiously in peripheral relativistic heavy-ion collisions. Virtual photons from one ion can fluctuate into quark-antiquark pairs and scatter from the second ion, emerging as vector mesons. The emitter and target are indistinguishable, so emission from the two ions will interfere. Vector mesons have negative parity so the interference is destructive, reducing the production of mesons with small transverse momentum. The mesons are short lived, and decay before emission from the two ions can overlap. However, the decay-product wave functions overlap and interfere since they are produced in an entangled state, providing an example of the Einstein-Podolsky-Rosen paradox. (c) 2000 The American Physical Society

Evaluation of reduced-dose CT for acute non-traumatic abdominal pain: evaluation of diagnostic accuracy in comparison to standard-dose CT.

Science.gov (United States)

Othman, Ahmed E; Bongers, Malte Niklas; Zinsser, Dominik; Schabel, Christoph; Wichmann, Julian L; Arshid, Rami; Notohamiprodjo, Mike; Nikolaou, Konstantin; Bamberg, Fabian

2018-01-01

Background Patients with acute non-traumatic abdominal pain often undergo abdominal computed tomography (CT). However, abdominal CT is associated with high radiation exposure. Purpose To evaluate diagnostic performance of a reduced-dose 100 kVp CT protocol with advanced modeled iterative reconstruction as compared to a linearly blended 120 kVp protocol for assessment of acute, non-traumatic abdominal pain. Material and Methods Two radiologists assessed 100 kVp and linearly blended 120 kVp series of 112 consecutive patients with acute non-traumatic pain (onset diagnostic confidence. Both 100 kVp and linearly blended 120 kVp series were quantitatively evaluated regarding radiation dose and image noise. Comparative statistics and diagnostic accuracy was calculated using receiver operating curve (ROC) statistics, with final clinical diagnosis/clinical follow-up as reference standard. Results Image quality was high for both series without detectable significant differences ( P = 0.157). Image noise and artifacts were rated low for both series but significantly higher for 100 kVp ( P ≤ 0.021). Diagnostic accuracy was high for both series (120 kVp: area under the curve [AUC] = 0.950, sensitivity = 0.958, specificity = 0.941; 100 kVp: AUC ≥ 0.910, sensitivity ≥ 0.937, specificity = 0.882; P ≥ 0.516) with almost perfect inter-rater agreement (Kappa = 0.939). Diagnostic confidence was high for both dose levels without significant differences (100 kVp 5, range 4-5; 120 kVp 5, range 3-5; P = 0.134). The 100 kVp series yielded 26.1% lower radiation dose compared with the 120 kVp series (5.72 ± 2.23 mSv versus 7.75 ± 3.02 mSv, P diagnostic accuracy for the assessment of acute non-traumatic abdominal pain.

A quality improvement project to reduce the intraoperative use of single-dose fentanyl vials across multiple patients in a pediatric institution.

Science.gov (United States)

Buck, David; Subramanyam, Rajeev; Varughese, Anna

2016-01-01

The use of a single-dose vial across multiple patients presents a risk to sterility and is against CDC guidelines. We initiated a quality improvement (QI) project to reduce the intraoperative use of single-dose vials of fentanyl across multiple patients at Cincinnati Children's Hospital Medical Center (CCHMC). The initial step of the improvement project was the development of a Key Driver Diagram. The diagram has the SMART aim of the project, key drivers inherent to the process we are trying to improve, and specific interventions targeting the key drivers. The number of patients each week receiving an IV dose of fentanyl, from a vial previously accessed for another patient was tracked in a high turnover operating room (OR). The improvement model used was based on the concept of building Plan-Do-Study-Act (PDSA) cycles. Tests of change included provider education, provision of an increased number of fentanyl vials, alternate wasting processes, and provision of single-use fentanyl syringes by the pharmacy. Prior to initiation of this project, it was common for a single fentanyl vial to be accessed for multiple patients. Our data showed an average percentage of failures of just over 50%. During the end of the project, after 7 months, the mean percentage failures had dropped to 5%. Preparation of 20 mcg single-use fentanyl syringes by pharmacy, combined with education of providers on appropriate use, was successful in reducing failures to below our goal of 25%. Appropriately sized fentanyl syringes prepared by pharmacy, education on correct use of single-dose vials, and reminders in the OR, reduced the percentage of patients receiving a dose of fentanyl from a vial previously accessed for another patient in a high-volume otolaryngology room. © 2015 John Wiley & Sons Ltd.

Radiolabeling optimization and reduced staff radiation exposure for high-dose 90Y-ibritumomab tiuxetan (HD-Zevalin)

International Nuclear Information System (INIS)

Papi, Stefano; Martano, Luigi; Garaboldi, Lucia; Rossi, Annalisa; Cremonesi, Marta; Grana, Chiara Maria; Paolucci, Daniele; Sansovini, Maddalena; Paganelli, Giovanni; Chinol, Marco

2010-01-01

Introduction: 90 Y-Zevalin labeling may cause severe finger radiation exposure, especially in high-dose protocols (HD-Zevalin), where up to 7.4 GBq could be injected. In this work, we optimized the labeling of HD-Zevalin with special regard to simplicity, speed, safety and radiation protection. Methods: Factors influencing labeling outcome (activity, specific activity, time, final volume, stability) were studied separately. The critical steps of a standard radiolabeling procedure were optimized to reduce finger exposure, developing an alternative labeling procedure and including a different 90 Y supplier. Finger doses were monitored by thermoluminescent dosimeters at each fingertip under anti-X gloves, considering both absolute values and values after normalization to 1.48 GBq. Results: Labeling of 90 Y-Zevalin was safe and reproducible up to 7.4 GBq with a simple and single-step procedure offering good stability for several hours. Radiolabeling specific activity was found critical, being kept at 740 MBq.mg -1 . Radiochemical purity values ≥98% were routinely achieved. The alternative procedure allowed a sensible reduction of finger dose, due to both the different 90 Y vial and the handling. Finger exposure was reduced from 6.6±4.3 to 3.1±0.8 mSv/1.48 GBq in the case of the original 90 Y vial and from 1.5±0.9 to 0.3±0.1 mSv/1.48 GBq using a shielded 90 Y vial. Conclusions: HD-Zevalin can be prepared in a safe and reproducible way, giving high radiochemical purity values, good stability and low finger exposure. This study may improve the safety of nuclear medicine professionals involved in the preparation of Zevalin.

Measurement of K/sub NN/, K/sub LL/ in p vector d → n vector X and p vector 9Be → n vector X at 800 MeV

International Nuclear Information System (INIS)

Riley, P.J.; Hollas, C.L.; Newsom, C.R.

1980-01-01

The spin transfer parameters, K/sub NN/ and K/sub LL/, have been measured in p vector d → n vector X and p vector 9 Be → n vector X at 0 0 and 800 MeV. The rather large values of K/sub LL/ demonstrate that this transfer mechanism will provide a useful source of polarized neutrons at LAMPF energies

Raster images vectorization system

OpenAIRE

Genytė, Jurgita

2006-01-01

The problem of raster images vectorization was analyzed and researched in this work. Existing vectorization systems are quite expensive, the results are inaccurate, and the manual vectorization of a large number of drafts is impossible. That‘s why our goal was to design and develop a new raster images vectorization system using our suggested automatic vectorization algorithm and the way to record results in a new universal vectorial file format. The work consists of these main parts: analysis...

Vectorization of phase space Monte Carlo code in FACOM vector processor VP-200

International Nuclear Information System (INIS)

Miura, Kenichi

1986-01-01

This paper describes the vectorization techniques for Monte Carlo codes in Fujitsu's Vector Processor System. The phase space Monte Carlo code FOWL is selected as a benchmark, and scalar and vector performances are compared. The vectorized kernel Monte Carlo routine which contains heavily nested IF tests runs up to 7.9 times faster in vector mode than in scalar mode. The overall performance improvement of the vectorized FOWL code over the original scalar code reaches 3.3. The results of this study strongly indicate that supercomputer can be a powerful tool for Monte Carlo simulations in high energy physics. (Auth.)

Chimpanzee Adenovirus Vector Ebola Vaccine.

Science.gov (United States)

Ledgerwood, Julie E; DeZure, Adam D; Stanley, Daphne A; Coates, Emily E; Novik, Laura; Enama, Mary E; Berkowitz, Nina M; Hu, Zonghui; Joshi, Gyan; Ploquin, Aurélie; Sitar, Sandra; Gordon, Ingelise J; Plummer, Sarah A; Holman, LaSonji A; Hendel, Cynthia S; Yamshchikov, Galina; Roman, Francois; Nicosia, Alfredo; Colloca, Stefano; Cortese, Riccardo; Bailer, Robert T; Schwartz, Richard M; Roederer, Mario; Mascola, John R; Koup, Richard A; Sullivan, Nancy J; Graham, Barney S

2017-03-09

The unprecedented 2014 epidemic of Ebola virus disease (EVD) prompted an international response to accelerate the availability of a preventive vaccine. A replication-defective recombinant chimpanzee adenovirus type 3-vectored ebolavirus vaccine (cAd3-EBO), encoding the glycoprotein from Zaire and Sudan species, that offers protection in the nonhuman primate model, was rapidly advanced into phase 1 clinical evaluation. We conducted a phase 1, dose-escalation, open-label trial of cAd3-EBO. Twenty healthy adults, in sequentially enrolled groups of 10 each, received vaccination intramuscularly in doses of 2×10 10 particle units or 2×10 11 particle units. Primary and secondary end points related to safety and immunogenicity were assessed throughout the first 8 weeks after vaccination; in addition, longer-term vaccine durability was assessed at 48 weeks after vaccination. In this small study, no safety concerns were identified; however, transient fever developed within 1 day after vaccination in two participants who had received the 2×10 11 particle-unit dose. Glycoprotein-specific antibodies were induced in all 20 participants; the titers were of greater magnitude in the group that received the 2×10 11 particle-unit dose than in the group that received the 2×10 10 particle-unit dose (geometric mean titer against the Zaire antigen at week 4, 2037 vs. 331; P=0.001). Glycoprotein-specific T-cell responses were more frequent among those who received the 2×10 11 particle-unit dose than among those who received the 2×10 10 particle-unit dose, with a CD4 response in 10 of 10 participants versus 3 of 10 participants (P=0.004) and a CD8 response in 7 of 10 participants versus 2 of 10 participants (P=0.07) at week 4. Assessment of the durability of the antibody response showed that titers remained high at week 48, with the highest titers in those who received the 2×10 11 particle-unit dose. Reactogenicity and immune responses to cAd3-EBO vaccine were dose-dependent. At

A new estimator for vector velocity estimation [medical ultrasonics

DEFF Research Database (Denmark)

Jensen, Jørgen Arendt

2001-01-01

A new estimator for determining the two-dimensional velocity vector using a pulsed ultrasound field is derived. The estimator uses a transversely modulated ultrasound field for probing the moving medium under investigation. A modified autocorrelation approach is used in the velocity estimation...... be introduced, and the velocity estimation is done at a fixed depth in tissue to reduce the influence of a spatial velocity spread. Examples for different velocity vectors and field conditions are shown using both simple and more complex field simulations. A relative accuracy of 10.1% is obtained...

Reducing dose in head CT: A phantom study

International Nuclear Information System (INIS)

Perez Diaz, M.; Carvalho, A. E.; Andrade, M. E.; Khoury, H. J.

2013-01-01

Thirty two head CT scans were acquired employing an anthropomorphic phantom which contains small lesions in posterior fosse, using 2 scanners, one with 64 slices 'Siemens Sensation' and other with 6 slices P hilip Brilliance . Parameters as Tube current (I [mA]), Collimation (C [mm]), spectrum energy (kVp) and dynamic range were changed during studies, looking for the optimal acquisition/processing conditions which permit both, good lesion detectability and the lowest dose. Air kerma (mGy) was measured with a ionization chamber and the air kerma index (Ca,100 [mGy]) was calculated as dose index. Image quality was analyzed by 5 expert criteria using a 5 points-scale (1=poor, 2=fair, 3=good, 4=very good, 5=excellent) and also using 5 Figure of merit in the spatial and frequency domains: Contrast C(%), Contrast to Noise Ratio CNR, Signal to Noise Ratio SNR, Normalized Mean Square Error (NMSE) and the Spectral Distance (SD). Objective and subjective results were correlated. We observed that doses can be diminished until a 25% respect to the usual practice with both technologies, diminishing mainly the mAs, without affecting lesion detection. As a result, we propose an optimized protocol for each scanner as follow: The use of 250 mAs, 120 kVp and the collimation of 6 slices x 1.50 mm per rotation to detect the lesions in posterior fosse with good image quality for the Philips Brilliance 6 tested, while 150 mAs, 100 kVp and slice thickness of 3 mm were needed with the Siemens Sensation 64. (Author)

Gene therapy of Fanconi anemia: preclinical efficacy using lentiviral vectors.

Science.gov (United States)

Galimi, Francesco; Noll, Meenakshi; Kanazawa, Yoshiyuki; Lax, Timothy; Chen, Cindy; Grompe, Markus; Verma, Inder M

2002-10-15

Fanconi anemia (FA) is an inherited cancer susceptibility syndrome caused by mutations in a DNA repair pathway including at least 6 genes (FANCA, FANCC, FANCD2, FANCE, FANCF, and FANCG). The clinical course of the disease is dominated by progressive, life-threatening bone marrow failure and high incidence of acute myelogenous leukemia and solid tumors. Allogeneic bone marrow transplantation (BMT) is a therapeutic option but requires HLA-matched donors. Gene therapy holds great promise for FA, but previous attempts to use retroviral vectors in humans have proven ineffective given the impaired proliferation potential of human FA hematopoietic progenitors (HPCs). In this work, we show that using lentiviral vectors efficient genetic correction can be achieved in quiescent hematopoietic progenitors from Fanca(-/-) and Fancc(-/-) mice. Long-term repopulating HPCs were transduced by a single exposure of unfractionated bone marrow mononuclear cells to lentivectors carrying the normal gene. Notably, no cell purification or cytokine prestimulation was necessary. Resistance to DNA- damaging agents was fully restored by lentiviral transduction, allowing for in vivo selection of the corrected cells with nonablative doses of cyclophosphamide. This study strongly supports the use of lentiviral vectors for FA gene therapy in humans.

Vectorization of DOT3.5 code

International Nuclear Information System (INIS)

Nonomiya, Iwao; Ishiguro, Misako; Tsutsui, Tsuneo

1990-07-01

In this report, we describe the vectorization of two-dimensional Sn-method radiation transport code DOT3.5. Vectorized codes are not only the NEA original version developed at ORNL but also the versions improved by JAERI: DOT3.5 FNS version for fusion neutronics analyses, DOT3.5 FER version for fusion reactor design, and ESPRIT module of RADHEAT-V4 code system for radiation shielding and radiation transport analyses. In DOT3.5, input/output processing time amounts to a great part of the elapsed time when a large number of energy groups and/or a large number of spatial mesh points are used in the calculated problem. Therefore, an improvement has been made for the speedup of input/output processing in the DOT3.5 FNS version, and DOT-DD (Double Differential cross section) code. The total speedup ratio of vectorized version to the original scalar one is 1.7∼1.9 for DOT3.5 NEA version, 2.2∼2.3 fro DOT3.5 FNS version, 1.7 for DOT3.5 FER version, and 3.1∼4.4 for RADHEAT-V4, respectively. The elapsed times for improved DOT3.5 FNS version and DOT-DD are reduced to 50∼65% that of the original version by the input/output speedup. In this report, we describe summary of codes, the techniques used for the vectorization and input/output speedup, verification of computed results, and speedup effect. (author)

Single-step biosynthesis and characterization of silver nanoparticles using Zornia diphylla leaves: A potent eco-friendly tool against malaria and arbovirus vectors.

Science.gov (United States)

Govindarajan, Marimuthu; Rajeswary, Mohan; Muthukumaran, Udaiyan; Hoti, S L; Khater, Hanem F; Benelli, Giovanni

2016-08-01

Mosquitoes (Diptera: Culicidae) are vectors of important pathogens and parasites, including malaria, dengue, chikungunya, Japanese encephalitis, lymphatic filariasis and Zika virus. The application of synthetic insecticides causes development of resistance, biological magnification of toxic substances through the food chain, and adverse effects on the environment and human health. In this scenario, eco-friendly control tools of mosquito vectors are a priority. Here single-step fabrication of silver nanoparticles (AgNP) using a cheap aqueous leaf extract of Zornia diphylla as reducing and capping agent pf Ag(+) ions has been carried out. Biosynthesized AgNP were characterized by UV-visible spectrophotometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDX) and X-ray diffraction analysis (XRD). The acute toxicity of Z. diphylla leaf extract and biosynthesized AgNP was evaluated against larvae of the malaria vector Anopheles subpictus, the dengue vector Aedes albopictus and the Japanese encephalitis vector Culex tritaeniorhynchus. Both the Z. diphylla leaf extract and Ag NP showed dose dependent larvicidal effect against all tested mosquito species. Compared to the leaf aqueous extract, biosynthesized Ag NP showed higher toxicity against An. subpictus, Ae. albopictus, and Cx. tritaeniorhynchus with LC50 values of 12.53, 13.42 and 14.61μg/ml, respectively. Biosynthesized Ag NP were found safer to non-target organisms Chironomus circumdatus, Anisops bouvieri and Gambusia affinis, with the respective LC50 values ranging from 613.11 to 6903.93μg/ml, if compared to target mosquitoes. Overall, our results highlight that Z. diphylla-fabricated Ag NP are a promising and eco-friendly tool against larval populations of mosquito vectors of medical and veterinary importance, with negligible toxicity against other non-target organisms. Copyright © 2016 Elsevier B

Vector grammars and PN machines

Institute of Scientific and Technical Information of China (English)

蒋昌俊

1996-01-01

The concept of vector grammars under the string semantic is introduced.The dass of vector grammars is given,which is similar to the dass of Chomsky grammars.The regular vector grammar is divided further.The strong and weak relation between the vector grammar and scalar grammar is discussed,so the spectrum system graph of scalar and vector grammars is made.The equivalent relation between the regular vector grammar and Petri nets (also called PN machine) is pointed.The hybrid PN machine is introduced,and its language is proved equivalent to the language of the context-free vector grammar.So the perfect relation structure between vector grammars and PN machines is formed.

Vector velocimeter

DEFF Research Database (Denmark)

2012-01-01

The present invention relates to a compact, reliable and low-cost vector velocimeter for example for determining velocities of particles suspended in a gas or fluid flow, or for determining velocity, displacement, rotation, or vibration of a solid surface, the vector velocimeter comprising a laser...

Dose Reduction Techniques

CERN Document Server

Waggoner, L O

2000-01-01

As radiation safety specialists, one of the things we are required to do is evaluate tools, equipment, materials and work practices and decide whether the use of these products or work practices will reduce radiation dose or risk to the environment. There is a tendency for many workers that work with radioactive material to accomplish radiological work the same way they have always done it rather than look for new technology or change their work practices. New technology is being developed all the time that can make radiological work easier and result in less radiation dose to the worker or reduce the possibility that contamination will be spread to the environment. As we discuss the various tools and techniques that reduce radiation dose, keep in mind that the radiological controls should be reasonable. We can not always get the dose to zero, so we must try to accomplish the work efficiently and cost-effectively. There are times we may have to accept there is only so much you can do. The goal is to do the sm...

Cloning vector

Science.gov (United States)

Guilfoyle, Richard A.; Smith, Lloyd M.

1994-01-01

A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site.

Cloning vector

Science.gov (United States)

Guilfoyle, R.A.; Smith, L.M.

1994-12-27

A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site. 2 figures.

Radiation absorbed doses in cephalography

International Nuclear Information System (INIS)

Eliasson, S.; Julin, P.; Richter, S.; Stenstroem, B.

1984-01-01

Radiation absorbed doses to different organs in the head and neck region in lateral (LAT) and postero-anterior (PA) cephalography were investigated. The doses were measured by thermoluminescence dosimeters (TLD) on a tissue equivalent phantom head. Lanthanide screens in speed group 4 were used at 90 and 85 k Vp. A near-focus aluminium dodger was used and the radiation beam was collimated strictly to the face. The maximum entrance dose from LAT was 0.25 mGy and 0.42 mGy from a PA exposure. The doses to the salivary glands ranged between 0.2 and 0.02 mGy at LAT and between 0.15 and 0.04 mGy at PA exposures. The average thyroid gland dose without any shielding was 0.11 mGy (LAT) and 0.06 mGy (PA). When a dodger was used the dose was reduced to 0.07 mGy (LAT). If the thyroid gland was sheilded off, the dose was further reduced to 0.01 mGy and if the thyroid region was collimated out of the primary radiation field the dose was reduced to only 0.005 mGy. (authors)

Median prior constrained TV algorithm for sparse view low-dose CT reconstruction.

Science.gov (United States)

Liu, Yi; Shangguan, Hong; Zhang, Quan; Zhu, Hongqing; Shu, Huazhong; Gui, Zhiguo

2015-05-01

It is known that lowering the X-ray tube current (mAs) or tube voltage (kVp) and simultaneously reducing the total number of X-ray views (sparse view) is an effective means to achieve low-dose in computed tomography (CT) scan. However, the associated image quality by the conventional filtered back-projection (FBP) usually degrades due to the excessive quantum noise. Although sparse-view CT reconstruction algorithm via total variation (TV), in the scanning protocol of reducing X-ray tube current, has been demonstrated to be able to result in significant radiation dose reduction while maintain image quality, noticeable patchy artifacts still exist in reconstructed images. In this study, to address the problem of patchy artifacts, we proposed a median prior constrained TV regularization to retain the image quality by introducing an auxiliary vector m in register with the object. Specifically, the approximate action of m is to draw, in each iteration, an object voxel toward its own local median, aiming to improve low-dose image quality with sparse-view projection measurements. Subsequently, an alternating optimization algorithm is adopted to optimize the associative objective function. We refer to the median prior constrained TV regularization as "TV_MP" for simplicity. Experimental results on digital phantoms and clinical phantom demonstrated that the proposed TV_MP with appropriate control parameters can not only ensure a higher signal to noise ratio (SNR) of the reconstructed image, but also its resolution compared with the original TV method. Copyright © 2015 Elsevier Ltd. All rights reserved.

Diagnostic doses and times for Phlebotomus papatasi and Lutzomyia longipalpis sand flies (Diptera: Psychodidae: Phlebotominae) using the CDC bottle bioassay to assess insecticide resistance.

Science.gov (United States)

Denlinger, David S; Creswell, Joseph A; Anderson, J Laine; Reese, Conor K; Bernhardt, Scott A

2016-04-15

Insecticide resistance to synthetic chemical insecticides is a worldwide concern in phlebotomine sand flies (Diptera: Psychodidae), the vectors of Leishmania spp. parasites. The CDC bottle bioassay assesses resistance by testing populations against verified diagnostic doses and diagnostic times for an insecticide, but the assay has been used limitedly with sand flies. The objective of this study was to determine diagnostic doses and diagnostic times for laboratory Lutzomyia longipalpis (Lutz & Nieva) and Phlebotomus papatasi (Scopoli) to ten insecticides, including pyrethroids, organophosphates, carbamates, and DDT, that are used worldwide to control vectors. Bioassays were conducted in 1,000-ml glass bottles each containing 10-25 sand flies from laboratory colonies of L. longipalpis or P. papatasi. Four pyrethroids, three organophosphates, two carbamates and one organochlorine, were evaluated. A series of concentrations were tested for each insecticide, and four replicates were conducted for each concentration. Diagnostic doses were determined only during the exposure bioassay for the organophosphates and carbamates. For the pyrethroids and DDT, diagnostic doses were determined for both the exposure bioassay and after a 24-hour recovery period. Both species are highly susceptible to the carbamates as their diagnostic doses are under 7.0 μg/ml. Both species are also highly susceptible to DDT during the exposure assay as their diagnostic doses are 7.5 μg/ml, yet their diagnostic doses for the 24-h recovery period are 650.0 μg/ml for Lu. longipalpis and 470.0 μg/ml for P. papatasi. Diagnostic doses and diagnostic times can now be incorporated into vector management programs that use the CDC bottle bioassay to assess insecticide resistance in field populations of Lu. longipalpis and P. papatasi. These findings provide initial starting points for determining diagnostic doses and diagnostic times for other sand fly vector species and wild populations using the CDC

Predators indirectly control vector-borne disease: linking predator-prey and host-pathogen models.

Science.gov (United States)

Moore, Sean M; Borer, Elizabeth T; Hosseini, Parviez R

2010-01-06

Pathogens transmitted by arthropod vectors are common in human populations, agricultural systems and natural communities. Transmission of these vector-borne pathogens depends on the population dynamics of the vector species as well as its interactions with other species within the community. In particular, predation may be sufficient to control pathogen prevalence indirectly via the vector. To examine the indirect effect of predators on vectored-pathogen dynamics, we developed a theoretical model that integrates predator-prey and host-pathogen theory. We used this model to determine whether predation can prevent pathogen persistence or alter the stability of host-pathogen dynamics. We found that, in the absence of predation, pathogen prevalence in the host increases with vector fecundity, whereas predation on the vector causes pathogen prevalence to decline, or even become extinct, with increasing vector fecundity. We also found that predation on a vector may drastically slow the initial spread of a pathogen. The predator can increase host abundance indirectly by reducing or eliminating infection in the host population. These results highlight the importance of studying interactions that, within the greater community, may alter our predictions when studying disease dynamics. From an applied perspective, these results also suggest situations where an introduced predator or the natural enemies of a vector may slow the rate of spread of an emerging vector-borne pathogen.

Probing deformed orbitals with vector A( vector e, e' N)B reactions

International Nuclear Information System (INIS)

Garrido, E.; Caballero, J.A.; Moya de Guerra, E.; Sarriguren, P.; Udias, J.M.

1995-01-01

We present results for response functions and asymmetries in the nuclear reactions 37 vector Ar( vector e, e' n) 36 Ar and 37 vector K( vector e,e' p) 36 Ar at quasifree kinematics. We compare PWIA results obtained using deformed HF wave functions with PWIA and DWIA results obtained assuming a spherical mean field. We show that the complex structure of the deformed orbitals can be probed by coincidence measurements with polarized beam and targets. ((orig.))

Evaluation of critical pathways, radionuclides, and remedial measures for reducing the radiological dose to returning populations at a former nuclear test site

Energy Technology Data Exchange (ETDEWEB)

Robison, W. L., LLNL

1997-11-01

Bikini Island, the major residence island at Bikini Atoll, was contaminated with radioactive fallout as a result of the BRAVO test conducted on March 1, 1954. We have identified the critical radionuclides and supplied radiological data needed to develop dose estimates for all possible exposure pathways. These estimates show that the major dose to returning populations would result from ingestion of cesium-137 (137 Cs) in locally grown terrestrial foods where the predicted population average effective dose exceeds current federal guidelines. Consequently, we designed several long-term field experiments to develop and evaluate methods to reduce the 137 Cs content in locally grown foods.This paper gives a general outline of the remediation experiments with a more detailed description of a preferred combined option. Our comparative evaluation on various remedial methods show that the combined option--potassium treatment of the entire islands with limited excavation of soil in village an d housing areas--will be effective in reducing the dose to about 10% of pretreatment levels, and offers very significant benefits with respect to adverse environmental impacts as well as savings in overall costs, time, and required expert resources.

Local and regional irradiation and brief reduced-dose chemotherapy for non-Hodgkin'n lymphoma (stage IE, IIE) of Waldeyer's ring with adult diseases

International Nuclear Information System (INIS)

Oguchi, Masahiko; Shikama, Naoto; Gomi, Koutarou; Izuno, Itaru; Takei, Kazuyoshi; Sasaki, Shigeru; Kiyono, Kunihiro

1997-01-01

Usually, the middle-aged patients with non-Hodgkin's lymphoma and concomitant other adult diseases can not be tolerable for intensive chemotherapy. Then we introduced a new regimen composed of radiation for local and surrounding lymph node areas, and brief reduced-dose chemotherapy into treatment for such patients. Thirty-eight patients with Stage I E or Stage II E non-Hodgkin's lymphoma of the Waldeyer's ring were a core of this study. Histopathologically they were diagnosed as diffuse intermediate grade. In addition, they suffered from other adult diseases such as cardiovascular diseases, cereblovascular disorders, diabetes mellitus, chronic liver diseases, etc. They were treated by the combined modality composed of reduced-dose chemotherapy (70%-ACOP: 2 cycles or 70%-MACOP-B: 8 weeks) and regional lymph node irradiation (30 Gy) puls boost irradiation (10 Gy) to involved area (total 40 Gy). No relapses were observed in the radiation field, the 5-year disease-free survival rate and cause-specific survival rate for all patients were 85.7% and 91.4%, respectively. There were no differences of the 5-year disease-free survival rate between stage I E and II E , among the pathological subtypes, among the complications and etc. The regimen composed of regional lymph node irradiation (30 Gy) puls boost irradiation (10 Gy) to involved area (total 40 Gy) and reduced-dose chemotherapy (70%-dose ACOP, 70%-dose MACOP-B) is a safe and useful approach to treatment for diffuse intermediate grade of B cell lymphoma in middle-aged patients having other adult diseases. (author)

An easy irradiation technique (partial half-beam) to reduce renal dose in radiotherapy of cervical cancer including paraaortic lymph nodes

International Nuclear Information System (INIS)

Vorwerk, H.; Wagner, D.; Christiansen, H.; Hess, C.F.; Hermann, R.M.

2008-01-01

Purpose: for radiation treatment of patients with cervical cancer and a high risk for paraaortic lymph node involvement, an easy three-dimensional (3-D) conformal irradiation technique (partial half-beam [PHB]) for protection of organs at risk, especially of renal tissue, was developed. Patients and methods: in five consecutive female patients a computed tomography scan was performed. Dose-volume histograms of the renal tissue and other organs at risk were analyzed for PHB, three other 3-D conformal techniques, and an intensity-modulated radiotherapy (IMRT) technique. Results: the PHB technique reduced the renal volume and volumes of other organs at risk exposed to radiation doses when comparing all patients to the other 3-D conformal techniques. With use of the IMRT technique more renal tissue volume received very low radiation doses (≤ 6.8 Gy) whereas the D 10 was lower than with the PHB technique. Conclusion: in female patients with cervical cancer and high risk for paraaortic lymph node involvement, the use of the PHB technique is recommended to reduce renal radiation exposure, if no IMRT technique should be applied. The PHB technique is very easily and fast applicable. (orig.)

Improvement of vector compensation method for vehicle magnetic distortion field

Energy Technology Data Exchange (ETDEWEB)

Pang, Hongfeng, E-mail: panghongfeng@126.com; Zhang, Qi; Li, Ji; Luo, Shitu; Chen, Dixiang; Pan, Mengchun; Luo, Feilu

2014-03-15

Magnetic distortions such as eddy-current field and low frequency magnetic field have not been considered in vector compensation methods. A new compensation method is proposed to suppress these magnetic distortions and improve compensation performance, in which the magnetic distortions related to measurement vectors and time are considered. The experimental system mainly consists of a three-axis fluxgate magnetometer (DM-050), an underwater vehicle and a proton magnetometer, in which the scalar value of magnetic field is obtained with the proton magnetometer and considered to be the true value. Comparing with traditional compensation methods, experimental results show that the magnetic distortions can be further reduced by two times. After compensation, error intensity and RMS error are reduced from 11684.013 nT and 7794.604 nT to 16.219 nT and 5.907 nT respectively. It suggests an effective way to improve the compensation performance of magnetic distortions. - Highlights: • A new vector compensation method is proposed for vehicle magnetic distortion. • The proposed model not only includes magnetometer error but also considers magnetic distortion. • Compensation parameters are computed directly by solving nonlinear equations. • Compared with traditional methods, the proposed method is not related with rotation angle rate. • Error intensity and RMS error can be reduced to 1/2 of the error with traditional methods.

Improvement of vector compensation method for vehicle magnetic distortion field

International Nuclear Information System (INIS)

Pang, Hongfeng; Zhang, Qi; Li, Ji; Luo, Shitu; Chen, Dixiang; Pan, Mengchun; Luo, Feilu

2014-01-01

Magnetic distortions such as eddy-current field and low frequency magnetic field have not been considered in vector compensation methods. A new compensation method is proposed to suppress these magnetic distortions and improve compensation performance, in which the magnetic distortions related to measurement vectors and time are considered. The experimental system mainly consists of a three-axis fluxgate magnetometer (DM-050), an underwater vehicle and a proton magnetometer, in which the scalar value of magnetic field is obtained with the proton magnetometer and considered to be the true value. Comparing with traditional compensation methods, experimental results show that the magnetic distortions can be further reduced by two times. After compensation, error intensity and RMS error are reduced from 11684.013 nT and 7794.604 nT to 16.219 nT and 5.907 nT respectively. It suggests an effective way to improve the compensation performance of magnetic distortions. - Highlights: • A new vector compensation method is proposed for vehicle magnetic distortion. • The proposed model not only includes magnetometer error but also considers magnetic distortion. • Compensation parameters are computed directly by solving nonlinear equations. • Compared with traditional methods, the proposed method is not related with rotation angle rate. • Error intensity and RMS error can be reduced to 1/2 of the error with traditional methods

Shading by Napier grass reduces malaria vector larvae in natural habitats in western Kenya highlands

NARCIS (Netherlands)

Wamae, P.M.; Githeko, A.K.; Menya, D.M.; Takken, W.

2010-01-01

Increased human population in the Western Kenya highlands has led to reclamation of natural swamps resulting in the creation of habitats suitable for the breeding of Anopheles gambiae, the major malaria vector in the region. Here we report on a study to restore the reclaimed swamp and reverse its

An investigation into techniques for reducing doses from neo-natal radiographic examinations

Energy Technology Data Exchange (ETDEWEB)

Wraith, C.M.; Martin, C.J. [Aberdeen Royal Hospitals NHS Trust (United Kingdom). Dept. of Bio-Medical Physics and Bio-Engineering; Stockdale, E.J.N.; McDonald, S.; Farquhar, B. [Royal Aberdeen Children`s Hospital (United Kingdom)

1995-10-01

A survey of radiation doses received by infants having radiography in a neo-natal unit was undertaken at Aberdeen Maternity Hospital. Options for dose reduction recommended by the CEC Lake Starnberg Group were investigated. Techniques were implemented for clinical evaluation after assessments of image quality with test objects and phantoms. Clinical image quality of radiographs was evaluated by paediatric radiologists using CEC criteria. Results revealed a clear relationship between entrance dose and patient weight, indicating that reference doses for infants could be linked to weight. (author).

Strengthening tactical planning and operational frameworks for vector control: the roadmap for malaria elimination in Namibia.

Science.gov (United States)

Chanda, Emmanuel; Ameneshewa, Birkinesh; Angula, Hans A; Iitula, Iitula; Uusiku, Pentrina; Trune, Desta; Islam, Quazi M; Govere, John M

2015-08-05

Namibia has made tremendous gains in malaria control and the epidemiological trend of the disease has changed significantly over the past years. In 2010, the country reoriented from the objective of reducing disease morbidity and mortality to the goal of achieving malaria elimination by 2020. This manuscript outlines the processes undertaken in strengthening tactical planning and operational frameworks for vector control to facilitate expeditious malaria elimination in Namibia. The information sources for this study included all available data and accessible archived documentary records on malaria vector control in Namibia. A methodical assessment of published and unpublished documents was conducted via a literature search of online electronic databases, Google Scholar, PubMed and WHO, using a combination of search terms. To attain the goal of elimination in Namibia, systems are being strengthened to identify and clear all infections, and significantly reduce human-mosquito contact. Particularly, consolidating vector control for reducing transmission at the identified malaria foci will be critical for accelerated malaria elimination. Thus, guarding against potential challenges and the need for evidence-based and sustainable vector control instigated the strengthening of strategic frameworks by: adopting the integrated vector management (IVM) strategy; initiating implementation of the global plan for insecticide resistance management (GPIRM); intensifying malaria vector surveillance; improving data collection and reporting systems on DDT; updating the indoor residual spraying (IRS) data collection and reporting tool; and, improving geographical reconnaissance using geographical information system-based satellite imagery. Universal coverage with IRS and long-lasting insecticidal nets, supplemented by larval source management in the context of IVM and guided by vector surveillance coupled with rational operationalization of the GPIRM, will enable expeditious

Linear Matrix Inequalities for Analysis and Control of Linear Vector Second-Order Systems

DEFF Research Database (Denmark)

Adegas, Fabiano Daher; Stoustrup, Jakob

2015-01-01

the Lyapunov matrix and the system matrices by introducing matrix multipliers, which potentially reduce conservativeness in hard control problems. Multipliers facilitate the usage of parameter-dependent Lyapunov functions as certificates of stability of uncertain and time-varying vector second-order systems......SUMMARY Many dynamical systems are modeled as vector second-order differential equations. This paper presents analysis and synthesis conditions in terms of LMI with explicit dependence in the coefficient matrices of vector second-order systems. These conditions benefit from the separation between....... The conditions introduced in this work have the potential to increase the practice of analyzing and controlling systems directly in vector second-order form. Copyright © 2014 John Wiley & Sons, Ltd....

Oncolytic Adenovirus: Strategies and Insights for Vector Design and Immuno-Oncolytic Applications

Directory of Open Access Journals (Sweden)

Hanni Uusi-Kerttula

2015-11-01

Full Text Available Adenoviruses (Ad are commonly used both experimentally and clinically, including oncolytic virotherapy applications. In the clinical area, efficacy is frequently hampered by the high rates of neutralizing immunity, estimated as high as 90% in some populations that promote vector clearance and limit bioavailability for tumor targeting following systemic delivery. Active tumor targeting is also hampered by the ubiquitous nature of the Ad5 receptor, hCAR, as well as the lack of highly tumor-selective targeting ligands and suitable targeting strategies. Furthermore, significant off-target interactions between the viral vector and cellular and proteinaceous components of the bloodstream have been documented that promote uptake into non-target cells and determine dose-limiting toxicities. Novel strategies are therefore needed to overcome the obstacles that prevent efficacious Ad deployment for wider clinical applications. The use of less seroprevalent Ad serotypes, non-human serotypes, capsid pseudotyping, chemical shielding and genetic masking by heterologous peptide incorporation are all potential strategies to achieve efficient vector escape from humoral immune recognition. Conversely, selective vector arming with immunostimulatory agents can be utilized to enhance their oncolytic potential by activation of cancer-specific immune responses against the malignant tissues. This review presents recent advantages and pitfalls occurring in the field of adenoviral oncolytic therapies.

Canine adenovirus type 2 vector generation via I-Sce1-mediated intracellular genome release.

Directory of Open Access Journals (Sweden)

Sandy Ibanes

Full Text Available When canine adenovirus type 2 (CAdV-2, or also commonly referred to as CAV-2 vectors are injected into the brain parenchyma they preferentially transduce neurons, are capable of efficient axonal transport to afferent regions, and allow transgene expression for at last >1 yr. Yet, translating these data into a user-friendly vector platform has been limited because CAV-2 vector generation is challenging. Generation of E1-deleted adenovirus vectors often requires transfection of linear DNA fragments of >30 kb containing the vector genome into an E1-transcomplementing cell line. In contrast to human adenovirus type 5 vector generation, CAV-2 vector generation is less efficient due, in part, to a reduced ability to initiate replication and poor transfectibility of canine cells with large, linear DNA fragments. To improve CAV-2 vector generation, we generated an E1-transcomplementing cell line expressing the estrogen receptor (ER fused to I-SceI, a yeast meganuclease, and plasmids containing the I-SceI recognition sites flanking the CAV-2 vector genome. Using transfection of supercoiled plasmid and intracellular genome release via 4-OH-tamoxifen-induced nuclear translocation of I-SceI, we improved CAV-2 vector titers 1,000 fold, and in turn increased the efficacy of CAV-2 vector generation.

Canine Adenovirus Type 2 Vector Generation via I-Sce1-Mediated Intracellular Genome Release

Science.gov (United States)

Ibanes, Sandy; Kremer, Eric J.

2013-01-01

When canine adenovirus type 2 (CAdV-2, or also commonly referred to as CAV-2) vectors are injected into the brain parenchyma they preferentially transduce neurons, are capable of efficient axonal transport to afferent regions, and allow transgene expression for at last >1 yr. Yet, translating these data into a user-friendly vector platform has been limited because CAV-2 vector generation is challenging. Generation of E1-deleted adenovirus vectors often requires transfection of linear DNA fragments of >30 kb containing the vector genome into an E1-transcomplementing cell line. In contrast to human adenovirus type 5 vector generation, CAV-2 vector generation is less efficient due, in part, to a reduced ability to initiate replication and poor transfectibility of canine cells with large, linear DNA fragments. To improve CAV-2 vector generation, we generated an E1-transcomplementing cell line expressing the estrogen receptor (ER) fused to I-SceI, a yeast meganuclease, and plasmids containing the I-SceI recognition sites flanking the CAV-2 vector genome. Using transfection of supercoiled plasmid and intracellular genome release via 4-OH-tamoxifen-induced nuclear translocation of I-SceI, we improved CAV-2 vector titers 1,000 fold, and in turn increased the efficacy of CAV-2 vector generation. PMID:23936483

Larvicidal effects of a neem (Azadirachta indica) oil formulation on the malaria vector Anopheles gambiae

NARCIS (Netherlands)

Okumu, F.O.; Knols, B.G.J.; Fillinger, U.

2007-01-01

Background - Larviciding is a key strategy used in many vector control programmes around the world. Costs could be reduced if larvicides could be manufactured locally. The potential of natural products as larvicides against the main African malaria vector, Anopheles gambiae s.s was evaluated.

Multi-perspective views of students’ difficulties with one-dimensional vector and two-dimensional vector

Science.gov (United States)

Fauzi, Ahmad; Ratna Kawuri, Kunthi; Pratiwi, Retno

2017-01-01

Researchers of students’ conceptual change usually collects data from written tests and interviews. Moreover, reports of conceptual change often simply refer to changes in concepts, such as on a test, without any identification of the learning processes that have taken place. Research has shown that students have difficulties with vectors in university introductory physics courses and high school physics courses. In this study, we intended to explore students’ understanding of one-dimensional and two-dimensional vector in multi perspective views. In this research, we explore students’ understanding through test perspective and interviews perspective. Our research study adopted the mixed-methodology design. The participants of this research were sixty students of third semester of physics education department. The data of this research were collected by testand interviews. In this study, we divided the students’ understanding of one-dimensional vector and two-dimensional vector in two categories, namely vector skills of the addition of one-dimensionaland two-dimensional vector and the relation between vector skills and conceptual understanding. From the investigation, only 44% of students provided correct answer for vector skills of the addition of one-dimensional and two-dimensional vector and only 27% students provided correct answer for the relation between vector skills and conceptual understanding.

Custodial vector model

Science.gov (United States)

Becciolini, Diego; Franzosi, Diogo Buarque; Foadi, Roshan; Frandsen, Mads T.; Hapola, Tuomas; Sannino, Francesco

2015-07-01

We analyze the Large Hadron Collider (LHC) phenomenology of heavy vector resonances with a S U (2 )L×S U (2 )R spectral global symmetry. This symmetry partially protects the electroweak S parameter from large contributions of the vector resonances. The resulting custodial vector model spectrum and interactions with the standard model fields lead to distinct signatures at the LHC in the diboson, dilepton, and associated Higgs channels.

Vector Differential Calculus

OpenAIRE

HITZER, Eckhard MS

2002-01-01

This paper treats the fundamentals of the vector differential calculus part of universal geometric calculus. Geometric calculus simplifies and unifies the structure and notation of mathematics for all of science and engineering, and for technological applications. In order to make the treatment self-contained, I first compile all important geometric algebra relationships,which are necesssary for vector differential calculus. Then differentiation by vectors is introduced and a host of major ve...

Vectorization, parallelization and porting of nuclear codes. Vectorization and parallelization. Progress report fiscal 1999

Energy Technology Data Exchange (ETDEWEB)

Adachi, Masaaki; Ogasawara, Shinobu; Kume, Etsuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Ishizuki, Shigeru; Nemoto, Toshiyuki; Kawasaki, Nobuo; Kawai, Wataru [Fujitsu Ltd., Tokyo (Japan); Yatake, Yo-ichi [Hitachi Ltd., Tokyo (Japan)

2001-02-01

Several computer codes in the nuclear field have been vectorized, parallelized and trans-ported on the FUJITSU VPP500 system, the AP3000 system, the SX-4 system and the Paragon system at Center for Promotion of Computational Science and Engineering in Japan Atomic Energy Research Institute. We dealt with 18 codes in fiscal 1999. These results are reported in 3 parts, i.e., the vectorization and the parallelization part on vector processors, the parallelization part on scalar processors and the porting part. In this report, we describe the vectorization and parallelization on vector processors. In this vectorization and parallelization on vector processors part, the vectorization of Relativistic Molecular Orbital Calculation code RSCAT, a microscopic transport code for high energy nuclear collisions code JAM, three-dimensional non-steady thermal-fluid analysis code STREAM, Relativistic Density Functional Theory code RDFT and High Speed Three-Dimensional Nodal Diffusion code MOSRA-Light on the VPP500 system and the SX-4 system are described. (author)

Dose Reduction Techniques

International Nuclear Information System (INIS)

WAGGONER, L.O.

2000-01-01

As radiation safety specialists, one of the things we are required to do is evaluate tools, equipment, materials and work practices and decide whether the use of these products or work practices will reduce radiation dose or risk to the environment. There is a tendency for many workers that work with radioactive material to accomplish radiological work the same way they have always done it rather than look for new technology or change their work practices. New technology is being developed all the time that can make radiological work easier and result in less radiation dose to the worker or reduce the possibility that contamination will be spread to the environment. As we discuss the various tools and techniques that reduce radiation dose, keep in mind that the radiological controls should be reasonable. We can not always get the dose to zero, so we must try to accomplish the work efficiently and cost-effectively. There are times we may have to accept there is only so much you can do. The goal is to do the smart things that protect the worker but do not hinder him while the task is being accomplished. In addition, we should not demand that large amounts of money be spent for equipment that has marginal value in order to save a few millirem. We have broken the handout into sections that should simplify the presentation. Time, distance, shielding, and source reduction are methods used to reduce dose and are covered in Part I on work execution. We then look at operational considerations, radiological design parameters, and discuss the characteristics of personnel who deal with ALARA. This handout should give you an overview of what it takes to have an effective dose reduction program

Dose Reduction Techniques

Energy Technology Data Exchange (ETDEWEB)

WAGGONER, L.O.

2000-05-16

As radiation safety specialists, one of the things we are required to do is evaluate tools, equipment, materials and work practices and decide whether the use of these products or work practices will reduce radiation dose or risk to the environment. There is a tendency for many workers that work with radioactive material to accomplish radiological work the same way they have always done it rather than look for new technology or change their work practices. New technology is being developed all the time that can make radiological work easier and result in less radiation dose to the worker or reduce the possibility that contamination will be spread to the environment. As we discuss the various tools and techniques that reduce radiation dose, keep in mind that the radiological controls should be reasonable. We can not always get the dose to zero, so we must try to accomplish the work efficiently and cost-effectively. There are times we may have to accept there is only so much you can do. The goal is to do the smart things that protect the worker but do not hinder him while the task is being accomplished. In addition, we should not demand that large amounts of money be spent for equipment that has marginal value in order to save a few millirem. We have broken the handout into sections that should simplify the presentation. Time, distance, shielding, and source reduction are methods used to reduce dose and are covered in Part I on work execution. We then look at operational considerations, radiological design parameters, and discuss the characteristics of personnel who deal with ALARA. This handout should give you an overview of what it takes to have an effective dose reduction program.

Elliptic-symmetry vector optical fields.

Science.gov (United States)

Pan, Yue; Li, Yongnan; Li, Si-Min; Ren, Zhi-Cheng; Kong, Ling-Jun; Tu, Chenghou; Wang, Hui-Tian

2014-08-11

We present in principle and demonstrate experimentally a new kind of vector fields: elliptic-symmetry vector optical fields. This is a significant development in vector fields, as this breaks the cylindrical symmetry and enriches the family of vector fields. Due to the presence of an additional degrees of freedom, which is the interval between the foci in the elliptic coordinate system, the elliptic-symmetry vector fields are more flexible than the cylindrical vector fields for controlling the spatial structure of polarization and for engineering the focusing fields. The elliptic-symmetry vector fields can find many specific applications from optical trapping to optical machining and so on.

Reducing abdominal CT radiation dose with the adaptive statistical iterative reconstruction technique in children: a feasibility study

Energy Technology Data Exchange (ETDEWEB)

Vorona, Gregory A. [The Children' s Hospital of Pittsburgh of UPMC, Department of Radiology, Pittsburgh, PA (United States); Allegheny General Hospital, Department of Radiology, Pittsburgh, PA (United States); Ceschin, Rafael C.; Clayton, Barbara L.; Sutcavage, Tom; Tadros, Sameh S.; Panigrahy, Ashok [The Children' s Hospital of Pittsburgh of UPMC, Department of Radiology, Pittsburgh, PA (United States)

2011-09-15

The use of the adaptive statistical iterative reconstruction (ASIR) algorithm has been shown to reduce radiation doses in adults undergoing abdominal CT studies while preserving image quality. To our knowledge, no studies have been done to validate the use of ASIR in children. To retrospectively evaluate differences in radiation dose and image quality in pediatric CT abdominal studies utilizing 40% ASIR compared with filtered-back projection (FBP). Eleven patients (mean age 8.5 years, range 2-17 years) had separate 40% ASIR and FBP enhanced abdominal CT studies on different days between July 2009 and October 2010. The ASIR studies utilized a 38% mA reduction in addition to our pediatric protocol mAs. Study volume CT dose indexes (CTDI{sub vol}) and dose-length products (DLP) were recorded. A consistent representative image was obtained from each study. The images were independently evaluated by two radiologists in a blinded manner for diagnostic utility, image sharpness and image noise. The average CTDI{sub vol} and DLP for the 40% ASIR studies were 4.25 mGy and 185.04 mGy-cm, compared with 6.75 mGy and 275.79 mGy-cm for the FBP studies, representing 37% and 33% reductions in both, respectively. The radiologists' assessments of subjective image quality did not demonstrate any significant differences between the ASIR and FBP images. In our experience, the use of 40% ASIR with a 38% decrease in mA lowers the radiation dose for children undergoing enhanced abdominal examinations by an average of 33%, while maintaining diagnostically acceptable images. (orig.)

Reducing abdominal CT radiation dose with the adaptive statistical iterative reconstruction technique in children: a feasibility study

International Nuclear Information System (INIS)

Vorona, Gregory A.; Ceschin, Rafael C.; Clayton, Barbara L.; Sutcavage, Tom; Tadros, Sameh S.; Panigrahy, Ashok

2011-01-01

The use of the adaptive statistical iterative reconstruction (ASIR) algorithm has been shown to reduce radiation doses in adults undergoing abdominal CT studies while preserving image quality. To our knowledge, no studies have been done to validate the use of ASIR in children. To retrospectively evaluate differences in radiation dose and image quality in pediatric CT abdominal studies utilizing 40% ASIR compared with filtered-back projection (FBP). Eleven patients (mean age 8.5 years, range 2-17 years) had separate 40% ASIR and FBP enhanced abdominal CT studies on different days between July 2009 and October 2010. The ASIR studies utilized a 38% mA reduction in addition to our pediatric protocol mAs. Study volume CT dose indexes (CTDI vol ) and dose-length products (DLP) were recorded. A consistent representative image was obtained from each study. The images were independently evaluated by two radiologists in a blinded manner for diagnostic utility, image sharpness and image noise. The average CTDI vol and DLP for the 40% ASIR studies were 4.25 mGy and 185.04 mGy-cm, compared with 6.75 mGy and 275.79 mGy-cm for the FBP studies, representing 37% and 33% reductions in both, respectively. The radiologists' assessments of subjective image quality did not demonstrate any significant differences between the ASIR and FBP images. In our experience, the use of 40% ASIR with a 38% decrease in mA lowers the radiation dose for children undergoing enhanced abdominal examinations by an average of 33%, while maintaining diagnostically acceptable images. (orig.)

Pharmacologic Effects in vivo in Brain by Vector-Mediated Peptide Drug Delivery

Science.gov (United States)

Bickel, Ulrich; Yoshikawa, Takayoshi; Landaw, Elliot M.; Faull, Kym F.; Pardridge, William M.

1993-04-01

Pharmacologic effects in brain caused by systemic administration of neuropeptides are prevented by poor transport of the peptide through the brain vascular endothelium, which comprises the blood-brain barrier in vivo. In the present study, successful application of a chimeric peptide approach to enhance drug delivery through the blood-brain barrier for the purpose of achieving a central nervous system pharmacologic effect is described. The chimeric peptide was formed by linkage of a potent vasoactive intestinal peptide (VIP) analogue, which had been monobiotinylated, to a drug transport vector. The vector consisted of a covalent conjugate of avidin and the OX26 monoclonal antibody to the transferrin receptor. Owing to the high concentration of transferrin receptors on brain capillary endothelia, OX26 targets brain and undergoes receptor-mediated transcytosis through the blood-brain barrier. Systemic infusion of low doses (12 μg/kg) of the VIP chimeric peptide in rats resulted in an in vivo central nervous system pharmacologic effect: a 65% increase in cerebral blood flow. Biotinylated VIP analogue without the brain transport vector was ineffective.

Low-dose spironolactone reduces plasma fibulin-1 levels in patients with type 2 diabetes and resistant hypertension

DEFF Research Database (Denmark)

Stolzenburg Oxlund, Christina; Cangemi, Claudia; Henriksen, J E

2015-01-01

Diabetic patients with hypertension are at particularly high risk of vascular damage and consequently cardiovascular and renal disease. Fibulin-1, an extracellular matrix glycoprotein, is increased in arterial tissue and plasma from individuals with type 2 diabetes. This study aimed to evaluate...... whether antihypertensive treatment with spironolactone changes plasma fibulin-1 levels. In a multicenter, double-blind, randomized, placebo-controlled study, 119 patients with type 2 diabetes and resistant hypertension were included. A dose of spironolactone 25 mg or matching placebo was added to previous....... Treatment with low-dose spironolactone reduced plasma fibulin-1 levels in patients with type 2 diabetes and resistant hypertension. This supports the hypothesis that the antihypertensive effect of the mineralocorticoid receptor blocker in part may be due to regression of vascular remodeling....

Chikungunya Virus–Vector Interactions

Directory of Open Access Journals (Sweden)

Lark L. Coffey

2014-11-01

Full Text Available Chikungunya virus (CHIKV is a mosquito-borne alphavirus that causes chikungunya fever, a severe, debilitating disease that often produces chronic arthralgia. Since 2004, CHIKV has emerged in Africa, Indian Ocean islands, Asia, Europe, and the Americas, causing millions of human infections. Central to understanding CHIKV emergence is knowledge of the natural ecology of transmission and vector infection dynamics. This review presents current understanding of CHIKV infection dynamics in mosquito vectors and its relationship to human disease emergence. The following topics are reviewed: CHIKV infection and vector life history traits including transmission cycles, genetic origins, distribution, emergence and spread, dispersal, vector competence, vector immunity and microbial interactions, and co-infection by CHIKV and other arboviruses. The genetics of vector susceptibility and host range changes, population heterogeneity and selection for the fittest viral genomes, dual host cycling and its impact on CHIKV adaptation, viral bottlenecks and intrahost diversity, and adaptive constraints on CHIKV evolution are also discussed. The potential for CHIKV re-emergence and expansion into new areas and prospects for prevention via vector control are also briefly reviewed.

Extended vector-tensor theories

Energy Technology Data Exchange (ETDEWEB)

Kimura, Rampei; Naruko, Atsushi; Yoshida, Daisuke, E-mail: rampei@th.phys.titech.ac.jp, E-mail: naruko@th.phys.titech.ac.jp, E-mail: yoshida@th.phys.titech.ac.jp [Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)

2017-01-01

Recently, several extensions of massive vector theory in curved space-time have been proposed in many literatures. In this paper, we consider the most general vector-tensor theories that contain up to two derivatives with respect to metric and vector field. By imposing a degeneracy condition of the Lagrangian in the context of ADM decomposition of space-time to eliminate an unwanted mode, we construct a new class of massive vector theories where five degrees of freedom can propagate, corresponding to three for massive vector modes and two for massless tensor modes. We find that the generalized Proca and the beyond generalized Proca theories up to the quartic Lagrangian, which should be included in this formulation, are degenerate theories even in curved space-time. Finally, introducing new metric and vector field transformations, we investigate the properties of thus obtained theories under such transformations.

Hyperbolic-symmetry vector fields.

Science.gov (United States)

Gao, Xu-Zhen; Pan, Yue; Cai, Meng-Qiang; Li, Yongnan; Tu, Chenghou; Wang, Hui-Tian

2015-12-14

We present and construct a new kind of orthogonal coordinate system, hyperbolic coordinate system. We present and design a new kind of local linearly polarized vector fields, which is defined as the hyperbolic-symmetry vector fields because the points with the same polarization form a series of hyperbolae. We experimentally demonstrate the generation of such a kind of hyperbolic-symmetry vector optical fields. In particular, we also study the modified hyperbolic-symmetry vector optical fields with the twofold and fourfold symmetric states of polarization when introducing the mirror symmetry. The tight focusing behaviors of these vector fields are also investigated. In addition, we also fabricate micro-structures on the K9 glass surfaces by several tightly focused (modified) hyperbolic-symmetry vector fields patterns, which demonstrate that the simulated tightly focused fields are in good agreement with the fabricated micro-structures.

Supergravity inspired vector curvaton

International Nuclear Information System (INIS)

Dimopoulos, Konstantinos

2007-01-01

It is investigated whether a massive Abelian vector field, whose gauge kinetic function is growing during inflation, can be responsible for the generation of the curvature perturbation in the Universe. Particle production is studied and it is shown that the vector field can obtain a scale-invariant superhorizon spectrum of perturbations with a reasonable choice of kinetic function. After inflation the vector field begins coherent oscillations, during which it corresponds to pressureless isotropic matter. When the vector field dominates the Universe, its perturbations give rise to the observed curvature perturbation following the curvaton scenario. It is found that this is possible if, after the end of inflation, the mass of the vector field increases at a phase transition at temperature of order 1 TeV or lower. Inhomogeneous reheating, whereby the vector field modulates the decay rate of the inflaton, is also studied

Recent Advances in Non-viral Vectors for Gene Delivery

Science.gov (United States)

Guo, Xia; Huang, Leaf

2011-01-01

CONSPECTUS Non-viral vectors, typically based on cationic lipids or polymers, are preferred due to safety concerns with viral vectors. So far, non-viral vectors can proficiently transfect cells in culture, but obtaining efficient nanomedicines is far from evident. To overcome the hurdles associated with non-viral vectors is significant for improving delivery efficiency and therapeutic effect of nucleic acid. The drawbacks include the strong interaction of cationic delivery vehicles with blood components, uptake by the reticuloendothelial system (RES), toxicity, targeting ability of the carriers to the cells of interest, and so on. PEGylation is the predominant method used to reduce the binding of plasma proteins with non-viral vectors and minimize the clearance by RES after intravenous administration. The nanoparticles that are not rapidly cleared from the circulation accumulate in the tumors due to the enhanced permeability and retention effect, and the targeting ligands attached to the distal end of the PEGylated components allow binding to the receptors on the target cell surface. Neutral or anionic liposomes have been also developed for systemic delivery of nucleic acids in experimental animal model. Designing and synthesizing novel cationic lipids and polymers, and binding nucleic acid with peptides, targeting ligands, polymers, or environmentally sensitive moieties also attract many attentions for resolving the problems encountered by non-viral vectors. The application of inorganic nanoparticles in nucleic acid delivery is an emerging field, too. Recently, different classes of non-viral vectors appear to be converging and the features of different classes of non-viral vectors could be combined in one strategy. More hurdles associated with efficient nucleic acid delivery therefore might be expected to be overcome. In this account, we will focus on these novel non-viral vectors, which are classified into multifunctional hybrid nucleic acid vectors, novel

S argassum muticum-synthesized silver nanoparticles: an effective control tool against mosquito vectors and bacterial pathogens.

Science.gov (United States)

Madhiyazhagan, Pari; Murugan, Kadarkarai; Kumar, Arjunan Naresh; Nataraj, Thiyagarajan; Dinesh, Devakumar; Panneerselvam, Chellasamy; Subramaniam, Jayapal; Mahesh Kumar, Palanisamy; Suresh, Udaiyan; Roni, Mathath; Nicoletti, Marcello; Alarfaj, Abdullah A; Higuchi, Akon; Munusamy, Murugan A; Benelli, Giovanni

2015-11-01

Mosquito-borne diseases represent a deadly threat for millions of people worldwide. Furthermore, pathogens and parasites polluting water also constitute a severe plague for populations of developing countries. In this research, silver nanoparticles (AgNP) were synthesized using the aqueous extract of the seaweed Sargassum muticum. The production of AgNP was confirmed by surface plasmon resonance band illustrated in UV-vis spectrophotometry. AgNP were characterized by FTIR, SEM, EDX, and XRD analyses. AgNP were mostly spherical in shape, crystalline in nature, with face-centered cubic geometry, and mean size was 43-79 nm. Toxicity of AgNP was assessed against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. In laboratory, AgNP were highly toxic against larvae and pupae of the three mosquito species. Maximum efficacy was observed against A. stephensi larvae, with LC50 ranging from 16.156 ppm (larva I) to 28.881 ppm (pupa). In the field, a single treatment with AgNP (10 × LC50) in water storage reservoirs was effective against the three mosquito vectors, allowing complete elimination of larval populations after 72 h. In ovicidal experiments, egg hatchability was reduced by 100% after treatment with 30 ppm of AgNP. Ovideterrence assays highlighted that 10 ppm of AgNP reduced oviposition rates of more than 70% in A. aegypti, A. stephensi, and C. quinquefasciatus (OAI = -0.61, -0.63, and -0.58, respectively). Antibacterial properties of AgNP were evaluated against Bacillus subtilis, Klebsiella pneumoniae, and Salmonella typhi using the agar disk diffusion and minimum inhibitory concentration protocol. AgNP tested at 50 ppm evoked growth inhibition zones larger than 5 mm in all tested bacteria. Overall, the chance to use S. muticum-synthesized AgNP for control of mosquito vectors seems promising since they are effective at low doses and may constitute an advantageous alternative to build newer and safer mosquito control tools. This is the first

Constraining vectors and axial-vectors in walking technicolour by a holographic principle

DEFF Research Database (Denmark)

D. Dietrich, Dennis; Kouvaris, Christoforos

2008-01-01

We use a holographic principle to study the low-energy spectrum of walking technicolour models. In particular, we predict the masses of the axial vectors as well as the decay constants of vectors and axial vectors as functions of the mass of the techni-rho. Given that there are very few...

Effects of switching from a reduced dose imiglucerase to velaglucerase in type 1 Gaucher disease: clinical and biochemical outcomes

NARCIS (Netherlands)

van Dussen, Laura; Cox, Timothy M.; Hendriks, Erik J.; Morris, Elizabeth; Akkerman, Erik M.; Maas, Mario; Groener, Johanna E. M.; Aerts, Johannes M. F. G.; Deegan, Patrick B.; Hollak, Carla E. M.

2012-01-01

This paper describes the effects of a switch to velaglucerase alfa in a group of adult patients with type 1 Gaucher disease, all of whom had previously had their dose reduced as a consequence of the worldwide imiglucerase shortage. Thirty-two patients from two large European Gaucher centers switched

Linear Energy Transfer Painting With Proton Therapy: A Means of Reducing Radiation Doses With Equivalent Clinical Effectiveness

International Nuclear Information System (INIS)

Fager, Marcus; Toma-Dasu, Iuliana; Kirk, Maura; Dolney, Derek; Diffenderfer, Eric S.; Vapiwala, Neha; Carabe, Alejandro

2015-01-01

Purpose: The purpose of this study was to propose a proton treatment planning method that trades physical dose (D) for dose-averaged linear energy transfer (LET d ) while keeping the radiobiologically weighted dose (D RBE ) to the target the same. Methods and Materials: The target is painted with LET d by using 2, 4, and 7 fields aimed at the proximal segment of the target (split target planning [STP]). As the LET d within the target increases with increasing number of fields, D decreases to maintain the D RBE the same as the conventional treatment planning method by using beams treating the full target (full target planning [FTP]). Results: The LET d increased 61% for 2-field STP (2STP) compared to FTP, 72% for 4STP, and 82% for 7STP inside the target. This increase in LET d led to a decrease of D with 5.3 ± 0.6 Gy for 2STP, 4.4 ± 0.7 Gy for 4STP, and 5.3 ± 1.1 Gy for 7STP, keeping the DRBE at 90% of the volume (DRBE, 90) constant to FTP. Conclusions: LET d painting offers a method to reduce prescribed dose at no cost to the biological effectiveness of the treatment

Linear Energy Transfer Painting With Proton Therapy: A Means of Reducing Radiation Doses With Equivalent Clinical Effectiveness

Energy Technology Data Exchange (ETDEWEB)

Fager, Marcus, E-mail: Marcus.Fager@UPHS.UPenn.edu [Department of Radiation Oncology, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Medical Radiation Physics, Stockholm University, Stockholm (Sweden); Toma-Dasu, Iuliana [Medical Radiation Physics, Stockholm University and Karolinska Institutet, Stockholm (Sweden); Kirk, Maura; Dolney, Derek; Diffenderfer, Eric S.; Vapiwala, Neha [Department of Radiation Oncology, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Carabe, Alejandro, E-mail: Alejandro.Carabe-Fernandez@UPHS.UPenn.edu [Department of Radiation Oncology, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States)

2015-04-01

Purpose: The purpose of this study was to propose a proton treatment planning method that trades physical dose (D) for dose-averaged linear energy transfer (LET{sub d}) while keeping the radiobiologically weighted dose (D{sub RBE}) to the target the same. Methods and Materials: The target is painted with LET{sub d} by using 2, 4, and 7 fields aimed at the proximal segment of the target (split target planning [STP]). As the LET{sub d} within the target increases with increasing number of fields, D decreases to maintain the D{sub RBE} the same as the conventional treatment planning method by using beams treating the full target (full target planning [FTP]). Results: The LET{sub d} increased 61% for 2-field STP (2STP) compared to FTP, 72% for 4STP, and 82% for 7STP inside the target. This increase in LET{sub d} led to a decrease of D with 5.3 ± 0.6 Gy for 2STP, 4.4 ± 0.7 Gy for 4STP, and 5.3 ± 1.1 Gy for 7STP, keeping the DRBE at 90% of the volume (DRBE, 90) constant to FTP. Conclusions: LET{sub d} painting offers a method to reduce prescribed dose at no cost to the biological effectiveness of the treatment.

Recommendation on vectors and vector-transmitted diseases

OpenAIRE

Netherlands Food and Consumer Product Safety Authority

2009-01-01

In view of their increasing risk of introduction and their possible implications in causing major disease outbreaks, vectors, as well as vector-transmitted diseases like dengue, West Nile disease, Lyme disease and bluetongue need to be recognised as a threat to public and animal health and to the economy, also in the Netherlands. There has been an increase in the incidence of these diseases in the past two to three decades. Climate changes and changes in the use of land, water managemen...

Gauge anomaly with vector and axial-vector fields in 6D curved space

Science.gov (United States)

Yajima, Satoshi; Eguchi, Kohei; Fukuda, Makoto; Oka, Tomonori

2018-03-01

Imposing the conservation equation of the vector current for a fermion of spin 1/2 at the quantum level, a gauge anomaly for the fermion coupling with non-Abelian vector and axial-vector fields in 6D curved space is expressed in tensorial form. The anomaly consists of terms that resemble the chiral U(1) anomaly and the commutator terms that disappear if the axial-vector field is Abelian.

Vector manifestation and violation of vector dominance in hot matter

International Nuclear Information System (INIS)

Harada, Masayasu; Sasaki, Chihiro

2004-01-01

We show the details of the calculation of the hadronic thermal corrections to the two-point functions in the effective field theory of QCD for pions and vector mesons based on the hidden local symmetry (HLS) in hot matter using the background field gauge. We study the temperature dependence of the pion velocity in the low-temperature region determined from the hadronic thermal corrections, and show that, due to the presence of the dynamical vector meson, the pion velocity is smaller than the speed of the light already at one-loop level, in contrast to the result obtained in the ordinary chiral perturbation theory including only the pion at one-loop. Including the intrinsic temperature dependences of the parameters of the HLS Lagrangian determined from the underlying QCD through the Wilsonian matching, we show how the vector manifestation (VM), in which the massless vector meson becomes the chiral partner of pion, is realized at the critical temperature. We present a new prediction of the VM on the direct photon-π-π coupling which measures the validity of the vector dominance (VD) of the electromagnetic form factor of the pion: we find that the VD is largely violated at the critical temperature, which indicates that the assumption of the VD made in several analyses on the dilepton spectra in hot matter may need to be weakened for consistently including the effect of the dropping mass of the vector meson

Efficient Vector-Based Forwarding for Underwater Sensor Networks

Directory of Open Access Journals (Sweden)

Peng Xie

2010-01-01

Full Text Available Underwater Sensor Networks (UWSNs are significantly different from terrestrial sensor networks in the following aspects: low bandwidth, high latency, node mobility, high error probability, and 3-dimensional space. These new features bring many challenges to the network protocol design of UWSNs. In this paper, we tackle one fundamental problem in UWSNs: robust, scalable, and energy efficient routing. We propose vector-based forwarding (VBF, a geographic routing protocol. In VBF, the forwarding path is guided by a vector from the source to the target, no state information is required on the sensor nodes, and only a small fraction of the nodes is involved in routing. To improve the robustness, packets are forwarded in redundant and interleaved paths. Further, a localized and distributed self-adaptation algorithm allows the nodes to reduce energy consumption by discarding redundant packets. VBF performs well in dense networks. For sparse networks, we propose a hop-by-hop vector-based forwarding (HH-VBF protocol, which adapts the vector-based approach at every hop. We evaluate the performance of VBF and HH-VBF through extensive simulations. The simulation results show that VBF achieves high packet delivery ratio and energy efficiency in dense networks and HH-VBF has high packet delivery ratio even in sparse networks.

A research agenda for malaria eradication: vector control.

Science.gov (United States)

2011-01-25

Different challenges are presented by the variety of malaria transmission environments present in the world today. In each setting, improved control for reduction of morbidity is a necessary first step towards the long-range goal of malaria eradication and a priority for regions where the disease burden is high. For many geographic areas where transmission rates are low to moderate, sustained and well-managed application of currently available tools may be sufficient to achieve local elimination. The research needs for these areas will be to sustain and perhaps improve the effectiveness of currently available tools. For other low-to-moderate transmission regions, notably areas where the vectors exhibit behaviours such as outdoor feeding and resting that are not well targeted by current strategies, new interventions that target predictable features of the biology/ecologies of the local vectors will be required. To achieve elimination in areas where high levels of transmission are sustained by very efficient vector species, radically new interventions that significantly reduce the vectorial capacity of wild populations will be needed. Ideally, such interventions should be implemented with a one-time application with a long-lasting impact, such as genetic modification of the vectorial capacity of the wild vector population.

Treatment for non-Hodgkin's lymphoma (stage I, II) of the elderly : usefulness of local and regional irradiation and brief reduced-dose chemotherapy

International Nuclear Information System (INIS)

Oguchi, Masahiko; Izuno, Itaru; Takei, Kazuyoshi; Shikama, Naoto; Sasaki, Shigeru; Gomi, Koutarou; Kiyono, Kunihiro; Takizawa, Masaomi; Sone, Shusuke

1996-01-01

Purpose: To examine the usefulness and safety of a new treatment regimen consisting of irradiation to the involved area and adjacent lymph-node area, and reduced-dose chemotherapy for elderly patients with non-Hodgkin's lymphoma. Materials and Methods: The core of this study was 38 elderly patients older than 65 years old with intermediate or high grade NHL, and concomitantly suffering from some other geriatric disease. They received involved-area irradiation (40 Gy), adjacent lymph-node irradiation (30 Gy), and reduced-dose chemotherapy (50-70 % ACOP 2 cycles or 70 % MACOP-B 4 weeks). Results: The completion rate of the treatment regimen was 100 %. The 5-year local control rate was 98 %. The 5-year disease free survival rate and the 5-year cause-specific survival rate for all patients were 70 % and 82 %, respectively. No treatment deaths were observed, and the rate of serious complications arising from the treatment was 3 %. Conclusion: Chemotherapy with a dose reduced to 50% or 70% of that prescribed in the original ACOP or MACOP-B, and irradiation to both the involved area and the adjacent lymph-node area are useful for treating elderly patients with Stage I, II intermediate B-cell NHL, who are at the same time suffering from some other geriatric disease

Genetic shifting: a novel approach for controlling vector-borne diseases.

Science.gov (United States)

Powell, Jeffrey R; Tabachnick, Walter J

2014-06-01

Rendering populations of vectors of diseases incapable of transmitting pathogens through genetic methods has long been a goal of vector geneticists. We outline a method to achieve this goal that does not involve the introduction of any new genetic variants to the target population. Rather we propose that shifting the frequencies of naturally occurring alleles that confer refractoriness to transmission can reduce transmission below a sustainable level. The program employs methods successfully used in plant and animal breeding. Because no artificially constructed genetically modified organisms (GMOs) are introduced into the environment, the method is minimally controversial. We use Aedes aegypti and dengue virus (DENV) for illustrative purposes but point out that the proposed program is generally applicable to vector-borne disease control. Copyright © 2014 Elsevier Ltd. All rights reserved.

A support vector density-based importance sampling for reliability assessment

International Nuclear Information System (INIS)

Dai, Hongzhe; Zhang, Hao; Wang, Wei

2012-01-01

An importance sampling method based on the adaptive Markov chain simulation and support vector density estimation is developed in this paper for efficient structural reliability assessment. The methodology involves the generation of samples that can adaptively populate the important region by the adaptive Metropolis algorithm, and the construction of importance sampling density by support vector density. The use of the adaptive Metropolis algorithm may effectively improve the convergence and stability of the classical Markov chain simulation. The support vector density can approximate the sampling density with fewer samples in comparison to the conventional kernel density estimation. The proposed importance sampling method can effectively reduce the number of structural analysis required for achieving a given accuracy. Examples involving both numerical and practical structural problems are given to illustrate the application and efficiency of the proposed methodology.

Heavy Scalar, Vector, and Axial-Vector Mesons in Hot and Dense Nuclear Medium

Directory of Open Access Journals (Sweden)

Arvind Kumar

2014-01-01

Full Text Available In this work we shall investigate the mass modifications of scalar mesons (D0; B0, vector mesons (D*; B*, and axial-vector mesons (D1; B1 at finite density and temperature of the nuclear medium. The above mesons are modified in the nuclear medium through the modification of quark and gluon condensates. We will find the medium modification of quark and gluon condensates within chiral SU(3 model through the medium modification of scalar-isoscalar fields σ and ζ at finite density and temperature. These medium modified quark and gluon condensates will further be used through QCD sum rules for the evaluation of in-medium properties of the above mentioned scalar, vector, and axial vector mesons. We will also discuss the effects of density and temperature of the nuclear medium on the scattering lengths of the above scalar, vector, and axial-vector mesons. The study of the medium modifications of the above mesons may be helpful for understanding their production rates in heavy-ion collision experiments. The results of present investigations of medium modifications of scalar, vector, and axial-vector mesons at finite density and temperature can be verified in the compressed baryonic matter (CBM experiment of FAIR facility at GSI, Germany.

Vector Fields on Product Manifolds

OpenAIRE

Kurz, Stefan

2011-01-01

This short report establishes some basic properties of smooth vector fields on product manifolds. The main results are: (i) On a product manifold there always exists a direct sum decomposition into horizontal and vertical vector fields. (ii) Horizontal and vertical vector fields are naturally isomorphic to smooth families of vector fields defined on the factors. Vector fields are regarded as derivations of the algebra of smooth functions.

SU-E-J-243: Possibility of Exposure Dose Reduction of Cone-Beam Computed Tomography in An Image Guided Patient Positioning System by Using Various Noise Suppression Filters

International Nuclear Information System (INIS)

Kamezawa, H; Arimura, H; Ohki, M; Shirieda, K; Kameda, N

2014-01-01

Purpose: To investigate the possibility of exposure dose reduction of the cone-beam computed tomography (CBCT) in an image guided patient positioning system by using 6 noise suppression filters. Methods: First, a reference dose (RD) and low-dose (LD)-CBCT (X-ray volume imaging system, Elekta Co.) images were acquired with a reference dose of 86.2 mGy (weighted CT dose index: CTDIw) and various low doses of 1.4 to 43.1 mGy, respectively. Second, an automated rigid registration for three axes was performed for estimating setup errors between a planning CT image and the LD-CBCT images, which were processed by 6 noise suppression filters, i.e., averaging filter (AF), median filter (MF), Gaussian filter (GF), bilateral filter (BF), edge preserving smoothing filter (EPF) and adaptive partial median filter (AMF). Third, residual errors representing the patient positioning accuracy were calculated as an Euclidean distance between the setup error vectors estimated using the LD-CBCT image and RD-CBCT image. Finally, the relationships between the residual error and CTDIw were obtained for 6 noise suppression filters, and then the CTDIw for LD-CBCT images processed by the noise suppression filters were measured at the same residual error, which was obtained with the RD-CBCT. This approach was applied to an anthropomorphic pelvic phantom and two cancer patients. Results: For the phantom, the exposure dose could be reduced from 61% (GF) to 78% (AMF) by applying the noise suppression filters to the CBCT images. The exposure dose in a prostate cancer case could be reduced from 8% (AF) to 61% (AMF), and the exposure dose in a lung cancer case could be reduced from 9% (AF) to 37% (AMF). Conclusion: Using noise suppression filters, particularly an adaptive partial median filter, could be feasible to decrease the additional exposure dose to patients in image guided patient positioning systems

SU-E-J-243: Possibility of Exposure Dose Reduction of Cone-Beam Computed Tomography in An Image Guided Patient Positioning System by Using Various Noise Suppression Filters

Energy Technology Data Exchange (ETDEWEB)

Kamezawa, H [Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka (Japan); Fujimoto General Hospital, Miyakonojo, Miyazaki (Japan); Arimura, H; Ohki, M [Faculty of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka (Japan); Shirieda, K; Kameda, N [Fujimoto General Hospital, Miyakonojo, Miyazaki (Japan)

2014-06-01

Purpose: To investigate the possibility of exposure dose reduction of the cone-beam computed tomography (CBCT) in an image guided patient positioning system by using 6 noise suppression filters. Methods: First, a reference dose (RD) and low-dose (LD)-CBCT (X-ray volume imaging system, Elekta Co.) images were acquired with a reference dose of 86.2 mGy (weighted CT dose index: CTDIw) and various low doses of 1.4 to 43.1 mGy, respectively. Second, an automated rigid registration for three axes was performed for estimating setup errors between a planning CT image and the LD-CBCT images, which were processed by 6 noise suppression filters, i.e., averaging filter (AF), median filter (MF), Gaussian filter (GF), bilateral filter (BF), edge preserving smoothing filter (EPF) and adaptive partial median filter (AMF). Third, residual errors representing the patient positioning accuracy were calculated as an Euclidean distance between the setup error vectors estimated using the LD-CBCT image and RD-CBCT image. Finally, the relationships between the residual error and CTDIw were obtained for 6 noise suppression filters, and then the CTDIw for LD-CBCT images processed by the noise suppression filters were measured at the same residual error, which was obtained with the RD-CBCT. This approach was applied to an anthropomorphic pelvic phantom and two cancer patients. Results: For the phantom, the exposure dose could be reduced from 61% (GF) to 78% (AMF) by applying the noise suppression filters to the CBCT images. The exposure dose in a prostate cancer case could be reduced from 8% (AF) to 61% (AMF), and the exposure dose in a lung cancer case could be reduced from 9% (AF) to 37% (AMF). Conclusion: Using noise suppression filters, particularly an adaptive partial median filter, could be feasible to decrease the additional exposure dose to patients in image guided patient positioning systems.

Light scattering of rectangular slot antennas: parallel magnetic vector vs perpendicular electric vector

Science.gov (United States)

Lee, Dukhyung; Kim, Dai-Sik

2016-01-01

We study light scattering off rectangular slot nano antennas on a metal film varying incident polarization and incident angle, to examine which field vector of light is more important: electric vector perpendicular to, versus magnetic vector parallel to the long axis of the rectangle. While vector Babinet’s principle would prefer magnetic field along the long axis for optimizing slot antenna function, convention and intuition most often refer to the electric field perpendicular to it. Here, we demonstrate experimentally that in accordance with vector Babinet’s principle, the incident magnetic vector parallel to the long axis is the dominant component, with the perpendicular incident electric field making a small contribution of the factor of 1/|ε|, the reciprocal of the absolute value of the dielectric constant of the metal, owing to the non-perfectness of metals at optical frequencies.

Generalization of concurrence vectors

International Nuclear Information System (INIS)

Yu Changshui; Song Heshan

2004-01-01

In this Letter, based on the generalization of concurrence vectors for bipartite pure state with respect to employing tensor product of generators of the corresponding rotation groups, we generalize concurrence vectors to the case of mixed states; a new criterion of separability of multipartite pure states is given out, for which we define a concurrence vector; we generalize the vector to the case of multipartite mixed state and give out a good measure of free entanglement

Vector Network Coding Algorithms

OpenAIRE

Ebrahimi, Javad; Fragouli, Christina

2010-01-01

We develop new algebraic algorithms for scalar and vector network coding. In vector network coding, the source multicasts information by transmitting vectors of length L, while intermediate nodes process and combine their incoming packets by multiplying them with L x L coding matrices that play a similar role as coding c in scalar coding. Our algorithms for scalar network jointly optimize the employed field size while selecting the coding coefficients. Similarly, for vector coding, our algori...

Structural Characteristics of Rotate Vector Reducer Free Vibration

Directory of Open Access Journals (Sweden)

Chuan Chen

2017-01-01

Full Text Available For RV reducer widely used in robots, vibration significantly affects its performance. A lumped parameter model is developed to investigate free vibration characteristics without and with gyroscopic effects. The dynamic model considers key factors affecting vibration such as involute and cycloid gear mesh stiffness, crankshaft bending stiffness, and bearing stiffness. For both nongyroscopic and gyroscopic systems, free vibrations are examined and compared with each other. Results reveal the specific structure of vibration modes for both systems, which results from symmetry structure of RV reducer. According to vibration of the central components, vibration modes of two systems can be classified into three types, rotational, translational, and planetary component modes. Different from nongyroscopic system, the eigenvalues with gyroscopic effects are complex-valued and speed-dependent. The eigenvalue for a range of carrier speeds is obtained by numerical simulation. Divergence and flutter instability is observed at speeds adjacent to critical speeds. Furthermore, the work studies effects of key factors, which include crankshaft eccentricity and the number of pins, on eigenvalues. Finally, experiment is performed to verify the effectiveness of the dynamic model. The research of this paper is helpful for the analysis on free vibration and dynamic design of RV reducer.

Safety and efficacy of reduced doses of Brucella melitensis strain Rev. 1 vaccine in pregnant Iranian fat-tailed ewes

Directory of Open Access Journals (Sweden)

Mohammad Ebrahimi

2012-12-01

Full Text Available Brucellosis is one of the most important zoonotic diseases and is a significant cause of abortion in animals. Brucella melitensis strain Rev. 1 is recommended as the most effective vaccine for small ruminants but the application of full doses in adult animals is restricted. This study was conducted to determine a proper reduced dose of vaccine which confers protection but which is not abortifacient in Iranian fat-tailed sheep. A total of 51 non-vaccinated pregnant ewes were divided into three main groups and several subgroups. Ewes in different groups were vaccinated at different stages of pregnancy and various subgroups were subcutaneously immunised with different quantities of the micro-organism (7.5 × 106, 106, 5 × 105. Ewes again became pregnant a year later and were challenged with the wild-type strain to evaluate the protection conferred. Results revealed that the proportion of vaccination-induced abortions was significantly higher in ewes immunised with 7.5 × 106 Rev. 1 organisms than in those which received 106 or 5 × 105 bacteria. While 80% of non-vaccinated ewes aborted after challenge, none of the vaccinated ewes aborted post-challenge. This study indicated that a reduced dose of Rev. 1 vaccine containing 106 or 5 × 105 live cells could be safely used to induce protection in Iranian fat-tailed sheep at various stages of pregnancy.

Short-term, high-dose glucocorticoid treatment does not contribute to reduced bone mineral density in patients with multiple sclerosis.

Science.gov (United States)

Olsson, A; Oturai, D B; Sørensen, P S; Oturai, P S; Oturai, A B

2015-10-01

Patients with multiple sclerosis (MS) are at increased risk of reduced bone mineral density (BMD). A contributing factor might be treatment with high-dose glucocorticoids (GCs). The objective of this paper is to assess bone mass in patients with MS and evaluate the importance of short-term, high-dose GC treatment and other risk factors that affect BMD in patients with MS. A total of 260 patients with MS received short-term high-dose GC treatment and had their BMD measured by dual x-ray absorptiometry. BMD was compared to a healthy age-matched reference population (Z-scores). Data regarding GCs, age, body mass index (BMI), serum 25(OH)D, disease duration and severity were collected retrospectively and analysed in a multiple linear regression analysis to evaluate the association between each risk factor and BMD. Osteopenia was present in 38% and osteoporosis in 7% of the study population. Mean Z-score was significantly below zero, indicating a decreased BMD in our MS patients. Multiple linear regression analysis showed no significant association between GCs and BMD. In contrast, age, BMI and disease severity were independently associated with both lumbar and femoral BMD. Reduced BMD was prevalent in patients with MS. GC treatment appears not to be the primary underlying cause of secondary osteoporosis in MS patients. © The Author(s), 2015.

Insecticide control of vector-borne diseases: when is insecticide resistance a problem?

Directory of Open Access Journals (Sweden)

Ana Rivero

Full Text Available Many of the most dangerous human diseases are transmitted by insect vectors. After decades of repeated insecticide use, all of these vector species have demonstrated the capacity to evolve resistance to insecticides. Insecticide resistance is generally considered to undermine control of vector-transmitted diseases because it increases the number of vectors that survive the insecticide treatment. Disease control failure, however, need not follow from vector control failure. Here, we review evidence that insecticide resistance may have an impact on the quality of vectors and, specifically, on three key determinants of parasite transmission: vector longevity, competence, and behaviour. We argue that, in some instances, insecticide resistance is likely to result in a decrease in vector longevity, a decrease in infectiousness, or in a change in behaviour, all of which will reduce the vectorial capacity of the insect. If this effect is sufficiently large, the impact of insecticide resistance on disease management may not be as detrimental as previously thought. In other instances, however, insecticide resistance may have the opposite effect, increasing the insect's vectorial capacity, which may lead to a dramatic increase in the transmission of the disease and even to a higher prevalence than in the absence of insecticides. Either way-and there may be no simple generality-the consequence of the evolution of insecticide resistance for disease ecology deserves additional attention.

Complex Polynomial Vector Fields

DEFF Research Database (Denmark)

Dias, Kealey

vector fields. Since the class of complex polynomial vector fields in the plane is natural to consider, it is remarkable that its study has only begun very recently. There are numerous fundamental questions that are still open, both in the general classification of these vector fields, the decomposition...... of parameter spaces into structurally stable domains, and a description of the bifurcations. For this reason, the talk will focus on these questions for complex polynomial vector fields.......The two branches of dynamical systems, continuous and discrete, correspond to the study of differential equations (vector fields) and iteration of mappings respectively. In holomorphic dynamics, the systems studied are restricted to those described by holomorphic (complex analytic) functions...

GATE Monte Carlo simulation of dose distribution using MapReduce in a cloud computing environment.

Science.gov (United States)

Liu, Yangchuan; Tang, Yuguo; Gao, Xin

2017-12-01

The GATE Monte Carlo simulation platform has good application prospects of treatment planning and quality assurance. However, accurate dose calculation using GATE is time consuming. The purpose of this study is to implement a novel cloud computing method for accurate GATE Monte Carlo simulation of dose distribution using MapReduce. An Amazon Machine Image installed with Hadoop and GATE is created to set up Hadoop clusters on Amazon Elastic Compute Cloud (EC2). Macros, the input files for GATE, are split into a number of self-contained sub-macros. Through Hadoop Streaming, the sub-macros are executed by GATE in Map tasks and the sub-results are aggregated into final outputs in Reduce tasks. As an evaluation, GATE simulations were performed in a cubical water phantom for X-ray photons of 6 and 18 MeV. The parallel simulation on the cloud computing platform is as accurate as the single-threaded simulation on a local server and the simulation correctness is not affected by the failure of some worker nodes. The cloud-based simulation time is approximately inversely proportional to the number of worker nodes. For the simulation of 10 million photons on a cluster with 64 worker nodes, time decreases of 41× and 32× were achieved compared to the single worker node case and the single-threaded case, respectively. The test of Hadoop's fault tolerance showed that the simulation correctness was not affected by the failure of some worker nodes. The results verify that the proposed method provides a feasible cloud computing solution for GATE.

Reduced-dose abdominopelvic CT using hybrid iterative reconstruction in suspected left-sided colonic diverticulitis

Energy Technology Data Exchange (ETDEWEB)

Laqmani, Azien; Dulz, Simon; Behzadi, Cyrus; Schmidt-Holtz, Jakob; Wassenberg, Felicia; Adam, Gerhard; Regier, Marc [University Medical Center Hamburg-Eppendorf, Department of Diagnostic and Interventional Radiology, Hamburg (Germany); Veldhoen, Simon [University Medical Center Wuerzburg, Department of Diagnostic and Interventional Radiology, Wuerzburg (Germany); Derlin, Thorsten [Hannover Medical School, Department of Nuclear Medicine, Hannover (Germany); Sehner, Susanne [University Medical Center Hamburg-Eppendorf, Department of Medical Biometry and Epidemiology, Hamburg (Germany); Nagel, Hans-Dieter [Scientific and Application-oriented Studies and Consulting in Radiology (SASCRAD), Buchholz (Germany)

2016-01-15

To assess the effect of hybrid iterative reconstruction (HIR) and filtered back projection (FBP) on abdominopelvic CT with reduced-dose (RD-APCT) in the evaluation of acute left-sided colonic diverticulitis (ALCD). Twenty-five consecutive patients with suspected ALCD who underwent RD-APCT (mean CTDIvol 11.2 ± 4.2 mGy) were enrolled in this study. Raw data were reconstructed using FBP and two increasing HIR levels, L4 and L6. Two radiologists assessed image quality, image noise and reviewer confidence in interpreting findings of ALCD, including wall thickening, pericolic fat inflammation, pericolic abscess, and contained or free extraluminal air. Objective image noise (OIN) was measured. OIN was reduced up to 54 % with HIR compared to FBP. Subjective image quality of HIR images was superior to FBP; subjective image noise was reduced. The detection rate of extraluminal air was higher with HIR L6. Reviewer confidence in interpreting CT findings of ALCD significantly improved with application of HIR. RD-APCT with HIR offers superior image quality and lower image noise compared to FBP, allowing a high level of reviewer confidence in interpreting CT findings in ALCD. HIR facilitates detection of ALCD findings that may be missed with the FBP algorithm. (orig.)

Short-term, high-dose glucocorticoid treatment does not contribute to reduced bone mineral density in patients with multiple sclerosis

DEFF Research Database (Denmark)

Olsson, A.; Oturai, D B; Sørensen, P S

2015-01-01

BACKGROUND: Patients with multiple sclerosis (MS) are at increased risk of reduced bone mineral density (BMD). A contributing factor might be treatment with high-dose glucocorticoids (GCs). OBJECTIVES: The objective of this paper is to assess bone mass in patients with MS and evaluate...... the importance of short-term, high-dose GC treatment and other risk factors that affect BMD in patients with MS. METHODS: A total of 260 patients with MS received short-term high-dose GC treatment and had their BMD measured by dual x-ray absorptiometry. BMD was compared to a healthy age-matched reference...... population (Z-scores). Data regarding GCs, age, body mass index (BMI), serum 25(OH)D, disease duration and severity were collected retrospectively and analysed in a multiple linear regression analysis to evaluate the association between each risk factor and BMD. RESULTS: Osteopenia was present in 38...

Vectorization, parallelization and porting of nuclear codes (vectorization and parallelization). Progress report fiscal 1998

International Nuclear Information System (INIS)

Ishizuki, Shigeru; Kawai, Wataru; Nemoto, Toshiyuki; Ogasawara, Shinobu; Kume, Etsuo; Adachi, Masaaki; Kawasaki, Nobuo; Yatake, Yo-ichi

2000-03-01

Several computer codes in the nuclear field have been vectorized, parallelized and transported on the FUJITSU VPP500 system, the AP3000 system and the Paragon system at Center for Promotion of Computational Science and Engineering in Japan Atomic Energy Research Institute. We dealt with 12 codes in fiscal 1998. These results are reported in 3 parts, i.e., the vectorization and parallelization on vector processors part, the parallelization on scalar processors part and the porting part. In this report, we describe the vectorization and parallelization on vector processors. In this vectorization and parallelization on vector processors part, the vectorization of General Tokamak Circuit Simulation Program code GTCSP, the vectorization and parallelization of Molecular Dynamics NTV (n-particle, Temperature and Velocity) Simulation code MSP2, Eddy Current Analysis code EDDYCAL, Thermal Analysis Code for Test of Passive Cooling System by HENDEL T2 code THANPACST2 and MHD Equilibrium code SELENEJ on the VPP500 are described. In the parallelization on scalar processors part, the parallelization of Monte Carlo N-Particle Transport code MCNP4B2, Plasma Hydrodynamics code using Cubic Interpolated Propagation Method PHCIP and Vectorized Monte Carlo code (continuous energy model / multi-group model) MVP/GMVP on the Paragon are described. In the porting part, the porting of Monte Carlo N-Particle Transport code MCNP4B2 and Reactor Safety Analysis code RELAP5 on the AP3000 are described. (author)

Fast computation of the characteristics method on vector computers

International Nuclear Information System (INIS)

Kugo, Teruhiko

2001-11-01

Fast computation of the characteristics method to solve the neutron transport equation in a heterogeneous geometry has been studied. Two vector computation algorithms; an odd-even sweep (OES) method and an independent sequential sweep (ISS) method have been developed and their efficiency to a typical fuel assembly calculation has been investigated. For both methods, a vector computation is 15 times faster than a scalar computation. From a viewpoint of comparison between the OES and ISS methods, the followings are found: 1) there is a small difference in a computation speed, 2) the ISS method shows a faster convergence and 3) the ISS method saves about 80% of computer memory size compared with the OES method. It is, therefore, concluded that the ISS method is superior to the OES method as a vectorization method. In the vector computation, a table-look-up method to reduce computation time of an exponential function saves only 20% of a whole computation time. Both the coarse mesh rebalance method and the Aitken acceleration method are effective as acceleration methods for the characteristics method, a combination of them saves 70-80% of outer iterations compared with a free iteration. (author)

Reduced dose measurement of absolute myocardial blood flow using dynamic SPECT imaging in a porcine model

International Nuclear Information System (INIS)

Timmins, Rachel; Klein, Ran; Petryk, Julia; Marvin, Brian; Kemp, Robert A. de; Ruddy, Terrence D.; Wells, R. Glenn; Wei, Lihui

2015-01-01

Purpose: Absolute myocardial blood flow (MBF) and myocardial flow reserve (MFR) measurements provide important additional information over traditional relative perfusion imaging. Recent advances in camera technology have made this possible with single-photon emission tomography (SPECT). Low dose protocols are desirable to reduce the patient radiation risk; however, increased noise may reduce the accuracy of MBF measurements. The authors studied the effect of reducing dose on the accuracy of dynamic SPECT MBF measurements. Methods: Nineteen 30–40 kg pigs were injected with 370 + 1110 MBq of Tc-99m sestamibi or tetrofosmin or 37 + 111 MBq of Tl-201 at rest + stress. Microspheres were injected simultaneously to measure MBF. The pigs were imaged in list-mode for 11 min starting at the time of injection using a Discovery NM 530c camera (GE Healthcare). Each list file was modified so that 3/4, 1/2, 1/4, 1/8, 1/16, and 1/32 of the original counts were included in the projections. Modified projections were reconstructed with CT-based attenuation correction and an energy window-based scatter correction and analyzed with FlowQuant kinetic modeling software using a 1-compartment model. A modified Renkin-Crone extraction function was used to convert the tracer uptake rate K1 to MBF values. The SPECT results were compared to those from microspheres. Results: Correlation between SPECT and microsphere MBF values for the full injected activity was r ≥ 0.75 for all 3 tracers and did not significantly degrade over all count levels. The mean MBF and MFR and the standard errors in the estimates were not significantly worse than the full-count data at 1/4-counts (Tc99m-tracers) and 1/2-counts (Tl-201). Conclusions: Dynamic SPECT measurement of MBF and MFR in pigs can be performed with 1/4 (Tc99m-tracers) or 1/2 (Tl-201) of the standard injected activity without significantly reducing accuracy and precision

Reduced dose measurement of absolute myocardial blood flow using dynamic SPECT imaging in a porcine model

Energy Technology Data Exchange (ETDEWEB)

Timmins, Rachel; Klein, Ran; Petryk, Julia; Marvin, Brian; Kemp, Robert A. de; Ruddy, Terrence D.; Wells, R. Glenn, E-mail: gwells@ottawaheart.ca [Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario K1Y4W7 (Canada); Wei, Lihui [Nordion, Inc., Ottawa, Ontario K2K 1X8 (Canada)

2015-09-15

Purpose: Absolute myocardial blood flow (MBF) and myocardial flow reserve (MFR) measurements provide important additional information over traditional relative perfusion imaging. Recent advances in camera technology have made this possible with single-photon emission tomography (SPECT). Low dose protocols are desirable to reduce the patient radiation risk; however, increased noise may reduce the accuracy of MBF measurements. The authors studied the effect of reducing dose on the accuracy of dynamic SPECT MBF measurements. Methods: Nineteen 30–40 kg pigs were injected with 370 + 1110 MBq of Tc-99m sestamibi or tetrofosmin or 37 + 111 MBq of Tl-201 at rest + stress. Microspheres were injected simultaneously to measure MBF. The pigs were imaged in list-mode for 11 min starting at the time of injection using a Discovery NM 530c camera (GE Healthcare). Each list file was modified so that 3/4, 1/2, 1/4, 1/8, 1/16, and 1/32 of the original counts were included in the projections. Modified projections were reconstructed with CT-based attenuation correction and an energy window-based scatter correction and analyzed with FlowQuant kinetic modeling software using a 1-compartment model. A modified Renkin-Crone extraction function was used to convert the tracer uptake rate K1 to MBF values. The SPECT results were compared to those from microspheres. Results: Correlation between SPECT and microsphere MBF values for the full injected activity was r ≥ 0.75 for all 3 tracers and did not significantly degrade over all count levels. The mean MBF and MFR and the standard errors in the estimates were not significantly worse than the full-count data at 1/4-counts (Tc99m-tracers) and 1/2-counts (Tl-201). Conclusions: Dynamic SPECT measurement of MBF and MFR in pigs can be performed with 1/4 (Tc99m-tracers) or 1/2 (Tl-201) of the standard injected activity without significantly reducing accuracy and precision.

Low Doses of Gamma Rays Reduce the Sensitivity of Cervical Carcinoma Cells to Subsequent Treatment with Cisplatin

International Nuclear Information System (INIS)

Osmak, M.; Brozovic, A.

2003-01-01

One of the major challenges of modern genetics is to apply recent advances in mutation research to improve the accuracy of the estimates of the genetic risk for humans. Because of the important implications for radiation protection, biological effects of low-dose radiation have been a focus of research in recent years. Previously we have found that human cervical carcinoma HeLa cells irradiated repeatedly with low doses of gamma rays (HeLa1500 cells) became resistant to cisplatin. In this study we examine whether this effect was caused by inhibition of apoptosis. In HeLa and HeLa1500 cells we determined the induction of apoptosis following the treatment with cisplatin (i) by counting apoptotic cells with characteristic morphological changes, (ii) by analysing the expression of apoptotic genes involved in cytochrome c/Apaf-1/caspase-9 and in Fas/FasL pathways by Western blot method, and (iii) by estimating the activities of caspases by commercial caspase detection kits. Our results show that low doses of gamma rays induced alterations in human cervical carcinoma cells that were reflected in inhibition of p53-independent cisplatin-induced apoptosis due to reduced activity of caspase 3. (author)

Effect of reduced dose schedules and intramuscular injection of anthrax vaccine adsorbed on immunological response and safety profile: a randomized trial.

Science.gov (United States)

Wright, Jennifer G; Plikaytis, Brian D; Rose, Charles E; Parker, Scott D; Babcock, Janiine; Keitel, Wendy; El Sahly, Hana; Poland, Gregory A; Jacobson, Robert M; Keyserling, Harry L; Semenova, Vera A; Li, Han; Schiffer, Jarad; Dababneh, Hanan; Martin, Sandra K; Martin, Stacey W; Marano, Nina; Messonnier, Nancy E; Quinn, Conrad P

2014-02-12

We evaluated an alternative administration route, reduced schedule priming series, and increased intervals between booster doses for anthrax vaccine adsorbed (AVA). AVA's originally licensed schedule was 6 subcutaneous (SQ) priming injections administered at months (m) 0, 0.5, 1, 6, 12 and 18 with annual boosters; a simpler schedule is desired. Through a multicenter randomized, double blind, non-inferiority Phase IV human clinical trial, the originally licensed schedule was compared to four alternative and two placebo schedules. 8-SQ group participants received 6 SQ injections with m30 and m42 "annual" boosters; participants in the 8-IM group received intramuscular (IM) injections according to the same schedule. Reduced schedule groups (7-IM, 5-IM, 4-IM) received IM injections at m0, m1, m6; at least one of the m0.5, m12, m18, m30 vaccine doses were replaced with saline. All reduced schedule groups received a m42 booster. Post-injection blood draws were taken two to four weeks following injection. Non-inferiority of the alternative schedules was compared to the 8-SQ group at m2, m7, and m43. Reactogenicity outcomes were proportions of injection site and systemic adverse events (AEs). The 8-IM group's m2 response was non-inferior to the 8-SQ group for the three primary endpoints of anti-protective antigen IgG geometric mean concentration (GMC), geometric mean titer, and proportion of responders with a 4-fold rise in titer. At m7 anti-PA IgG GMCs for the three reduced dosage groups were non-inferior to the 8-SQ group GMCs. At m43, 8-IM, 5-IM, and 4-IM group GMCs were superior to the 8-SQ group. Solicited injection site AEs occurred at lower proportions in the IM group compared to SQ. Route of administration did not influence the occurrence of systemic AEs. A 3 dose IM priming schedule with doses administered at m0, m1, and m6 elicited long term immunological responses and robust immunological memory that was efficiently stimulated by a single booster vaccination at

The impact of the oxygen scavenger on the dose-rate dependence and dose sensitivity of MAGIC type polymer gels

Science.gov (United States)

Khan, Muzafar; Heilemann, Gerd; Kuess, Peter; Georg, Dietmar; Berg, Andreas

2018-03-01

Recent developments in radiation therapy aimed at more precise dose delivery along with higher dose gradients (dose painting) and more efficient dose delivery with higher dose rates e.g. flattening filter free (FFF) irradiation. Magnetic-resonance-imaging based polymer gel dosimetry offers 3D information for precise dose delivery techniques. Many of the proposed polymer gels have been reported to exhibit a dose response, measured as relaxation rate ΔR2(D), which is dose rate dependent. A lack of or a reduced dose-rate sensitivity is very important for dosimetric accuracy, especially with regard to the increasing clinical use of FFF irradiation protocols with LINACs at high dose rates. Some commonly used polymer gels are based on Methacrylic-Acid-Gel-Initiated-by-Copper (MAGIC). Here, we report on the dose sensitivity (ΔR2/ΔD) of MAGIC-type gels with different oxygen scavenger concentration for their specific dependence on the applied dose rate in order to improve the dosimetric performance, especially for high dose rates. A preclinical x-ray machine (‘Yxlon’, E  =  200 kV) was used for irradiation to cover a range of dose rates from low \\dot{D} min  =  0.6 Gy min-1 to high \\dot{D} max  =  18 Gy min-1. The dose response was evaluated using R2-imaging of the gel on a human high-field (7T) MR-scanner. The results indicate that all of the investigated dose rates had an impact on the dose response in polymer gel dosimeters, being strongest in the high dose region and less effective for low dose levels. The absolute dose rate dependence \\frac{(Δ R2/Δ D)}{Δ \\dot{D}} of the dose response in MAGIC-type gel is significantly reduced using higher concentrations of oxygen scavenger at the expense of reduced dose sensitivity. For quantitative dose evaluations the relative dose rate dependence of a polymer gel, normalized to its sensitivity is important. Based on this normalized sensitivity the dose rate sensitivity was reduced distinctly

Direct dose mapping versus energy/mass transfer mapping for 4D dose accumulation: fundamental differences and dosimetric consequences.

Science.gov (United States)

Li, Haisen S; Zhong, Hualiang; Kim, Jinkoo; Glide-Hurst, Carri; Gulam, Misbah; Nurushev, Teamour S; Chetty, Indrin J

2014-01-06

The direct dose mapping (DDM) and energy/mass transfer (EMT) mapping are two essential algorithms for accumulating the dose from different anatomic phases to the reference phase when there is organ motion or tumor/tissue deformation during the delivery of radiation therapy. DDM is based on interpolation of the dose values from one dose grid to another and thus lacks rigor in defining the dose when there are multiple dose values mapped to one dose voxel in the reference phase due to tissue/tumor deformation. On the other hand, EMT counts the total energy and mass transferred to each voxel in the reference phase and calculates the dose by dividing the energy by mass. Therefore it is based on fundamentally sound physics principles. In this study, we implemented the two algorithms and integrated them within the Eclipse treatment planning system. We then compared the clinical dosimetric difference between the two algorithms for ten lung cancer patients receiving stereotactic radiosurgery treatment, by accumulating the delivered dose to the end-of-exhale (EE) phase. Specifically, the respiratory period was divided into ten phases and the dose to each phase was calculated and mapped to the EE phase and then accumulated. The displacement vector field generated by Demons-based registration of the source and reference images was used to transfer the dose and energy. The DDM and EMT algorithms produced noticeably different cumulative dose in the regions with sharp mass density variations and/or high dose gradients. For the planning target volume (PTV) and internal target volume (ITV) minimum dose, the difference was up to 11% and 4% respectively. This suggests that DDM might not be adequate for obtaining an accurate dose distribution of the cumulative plan, instead, EMT should be considered.