bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analyzing the impact of intrafraction motion: Correlation of different dose metrics with changes in target D95%
Authors: Waghorn Ben J. , Meeks Sanford L. , Langen Katja M. 
Published: July 2011

Purpose:A number of techniques are available to determine the dosimetric impact of intrafraction motion during intensity modulated radiation therapy (IMRT). Motion‐induced dose perturbations can be determined both computationally and experimentally using a number of different dosimetric metrics. However, these measures may lead to different conclusions regarding the clinical impact of motion. This study compares the analysis of identical dose perturbations using different dosimetric metrics. Calculated changes in target D95% are used as a reference.Methods:A total of 3768 motion‐encoded dose distributions were calculated for nine lung tumor patients. The motion‐encoded dose distributions were compared to static dose distributions using three dosimetric metrics: 2D γ, 3D γ, and histogram analysis. Each of these metrics was used to analyze dose perturbations both globally and within the target structure. Furthermore, the failing voxels were analyzed separately according to failure mode, i.e., under vs. over‐dosed voxels. Metrics were evaluated based on their agreement with changes in target D95%. Evaluations included the metrics' maximum average sensitivity and specificity (MASS) in detecting unacceptable deliveries, a coefficient correlated to ranking (τ), and the linear correlation coefficient, r.Results:Of the evaluated metrics, the histogram metric restricted to the under‐dosed voxels within the target agreed best with changes in target D95%. This metric achieved a MASS of 0.93, a τ of 0.69, and an r‐value of 0.85. In comparison, the unrestricted 2D γ metric achieved MASS = 0.77, τ = 0.40, and r = 0.67. Restricting the 2D γ test both geographically and in failure mode increased the MASS to 0.85, τ to 0.70, and the r‐value to 0.80.Conclusions:This study suggests that any clinical decisions based solely on an unrestricted 2D γ metric are suboptimal. A geographic and failure mode restriction can improve results. The remaining uncertainties with non‐DVH (dose volume histogram) based metrics should be kept in mind when they are used to evaluate the dosimetric impact of target motion.
Use of the cross‐correlation component of the multiscale structural similarity metric (R* metric) for the evaluation of medical images
Authors: Prieto Gabriel , Guibelalde Eduardo , Chevalier Margarita , Turrero Agustín 
Published: July 2011

Purpose:The aim of the present work is to analyze the potential of the cross‐correlation component of the multiscale structural similarity metric (R*) to predict human performance in detail detection tasks closely related with diagnostic x‐ray images. To check the effectiveness of R*, the authors have initially applied this metric to a contrast detail detection task.Methods:Threshold contrast visibility using the R* metric was determined for two sets of images of a contrast‐detail phantom (CDMAM). Results from R* and human observers were compared as far as the contrast threshold was concerned. A comparison between the R* metric and two algorithms currently used to evaluate CDMAM images was also performed.Results:Similar trends for the CDMAM detection task of human observers and R* were found in this study. Threshold contrast visibility values using R* are statistically indistinguishable from those obtained by human observers (F‐test statistics:p > 0.05).Conclusions:These results using R* show that it could be used to mimic human observers for certain tasks, such as the determination of contrast detail curves in the presence of uniform random noise backgrounds. The R* metric could also outperform other metrics and algorithms currently used to evaluate CDMAM images and can automate this evaluation task.
On the Monte Carlo simulation of electron transport in the sub‐1 keV energy range
Authors: Thomson Rowan M. , Kawrakow Iwan 
Published: July 2011

Purpose:The validity of “classic” Monte Carlo (MC) simulations of electron and positron transport at sub‐1 keV energies is investigated in the context of quantum theory.Methods:Quantum theory dictates that uncertainties on the position and energy‐momentum four‐vectors of radiation quanta obey Heisenberg's uncertainty relation; however, these uncertainties are neglected in “classical” MC simulations of radiation transport in which position and momentum are known precisely. Using the quantum uncertainty relation and electron mean free path, the magnitudes of uncertainties on electron position and momentum are calculated for different kinetic energies; a validity bound on the classical simulation of electron transport is derived.Results:In order to satisfy the Heisenberg uncertainty principle, uncertainties of 5% must be assigned to position and momentum for 1 keV electrons in water; at 100 eV, these uncertainties are 17 to 20% and are even larger at lower energies. In gaseous media such as air, these uncertainties are much smaller (less than 1% for electrons with energy 20 eV or greater).Conclusions:The classical Monte Carlo transport treatment is questionable for sub‐1 keV electrons in condensed water as uncertainties on position and momentum must be large (relative to electron momentum and mean free path) to satisfy the quantum uncertainty principle. Simulations which do not account for these uncertainties are not faithful representations of the physical processes, calling into question the results of MC track structure codes simulating sub‐1 keV electron transport. Further, the large difference in the scale at which quantum effects are important in gaseous and condensed media suggests that track structure measurements in gases are not necessarily representative of track structure in condensed materials on a micrometer or a nanometer scale.
Production and dosimetric aspects of the potent Auger emitter 58mCo for targeted radionuclide therapy of small tumors
Authors: Thisgaard H. , Elema D.R. , Jensen M. 
Published: July 2011

Purpose:Based on theoretical calculations, the Auger emitter58mCo has been identified as a potent nuclide for targeted radionuclide therapy of small tumors. During the production of this isotope, the coproduction of the long‐lived ground state 58gCo is unfortunately unavoidable, as is ingrowth of the ground state following the isomeric decay of 58mCo. The impact of 58gCo as a β+‐ and γ‐emitting impurity should be included in the dosimetric analysis. The purpose of this study was to investigate this critical part of dosimetry based on experimentally determined production yields of 58mCo and 58gCo using a low‐energy cyclotron. Also, the cellular S‐values for 58mCo have been calculated and are presented here for the first time.Methods:58mCo was produced via the 58Fe(p,n)58mCo nuclear reaction on highly enriched 58Fe metal. In addition, radiochemical separations of produced radio‐cobalt from natFe target material were performed. The theoretical subcellular dosimetry calculations for 58mCo and 58gCo were performed using the MIRD formalism, and the impact of the increasing ground state impurity on the tumor‐to‐normal‐tissue dose ratios (TND) per disintegration as a function of time after end of bombardment (EOB) was calculated.Results:192 ± 8 MBq of58mCo was produced in the irradiation corresponding to a production yield of 10.7 MBq/μAh. The activity of 58gCo was measured to be 0.85% ± 0.04% of the produced 58mCo activity at EOB. The radio‐cobalt yields in the rapid separations were measured to be >97% with no detectable iron contaminations in the cobalt fractions. Due to the unavoidable coproduction and ingrowth of the long‐lived ground state 58gCo, the TND and the potency of the 58mCo decrease with time after EOB. If a future treatment with a 58mCo labeled compound is not initiated before, e.g., 21 h after EOB, the resulting TND will be approximately 50% of the TND of ‘pure’ 58mCo as a result of the increased normal tissue dose from the ground state.Conclusions: The Auger emitter 58mCo is a potent radioisotope for targeted radionuclide therapy, and the production of therapeutic quantities should be achievable using a small biomedical cyclotron. However, the unavoidable coproduction and ingrowth of the long‐lived ground state 58gCo requires fast radiochemical processing and use of future 58mCo‐labeled radiopharmaceuticals in order to exploit the high achievable TND of 58mCo.
Iterative reconstruction for differential phase contrast imaging using spherically symmetric basis functions
Authors: Köhler Thomas , Brendel Bernhard , Roessl Ewald 
Published: July 2011

Purpose:The purpose of this work is to combine two areas of active research in tomographic x‐ray imaging. The first one is the use of iterative reconstruction (IR) techniques. The second one is differential phase contrast imaging (DPCI).Methods:The authors derive a maximum likelihood (ML) reconstruction algorithm with regularization for DPCI. Forward and back‐projection are implemented using spherically symmetric basis functions (blobs) and differential footprints, thus completely avoiding the need for numerical differentiation throughout the reconstruction process. The method is applied to the problem of reconstruction of an object from sparsely sampled projections.Results:The results show that the proposed method can handle the sparsely sampled data efficiently. In particular no streak artifacts are visible which are present in images obtained by filtered back‐projection (FBP).Conclusions:IR algorithms have a wide spectrum of proven advantages in the area of conventional computed tomography. The present work describes for the first time, how a matched forward and back‐projection can be implemented for DPCI, which is furthermore free of any heuristics. The newly developed ML reconstruction algorithm for DPCI shows that for the case of sparsely sampled projection data, an improvement in image quality is obtained that is qualitatively comparable to a corresponding situation in conventional x‐ray imaging. Based on the proposed operators for forward and back‐projection, a large variety of IR algorithms is thus made available for DPCI.
Impaired Humoral Response to Vaccines among HIV-Exposed Uninfected Infants
Authors: Abramczuk Beatriz Mariana , Mazzola Taís Nitsch , Moreno Yara Maria Franco , Zorzeto Tatiane Queiroz , Quintilio Wagner , Wolf Paulo Silva , Blotta Maria Heloisa , Morcillo André Moreno , da Silva Marcos Tadeu Nolasco , dos Santos Vilela Maria Marluce 
Published: July 2011

ABSTRACTLittle is known about the vaccine protective response for infants born from HIV-infected mothers. We evaluated the antibody response to hepatitis B, tetanus, and diphtheria vaccine in vertically HIV-exposed uninfected infants and compared them to those of control infants not exposed to the virus. The quantitative determination of specific neutralizing antibodies against hepatitis B, diphtheria, and tetanus were performed blindly on serum samples. The results showed that 6.7% of the HIV-exposed uninfected individuals were nonresponders to hepatitis B vaccine (anti-HBs titer, <10 mIU/ml), and 64.4% were very good responders (anti-HBs titer, ≥1,000 mIU/ml), whereas only 3.6% of the nonexposed infants were nonresponders (χ2=10.93; 1 df). The HIV-exposed uninfected infants showed protective titers for diphtheria and tetanus but lower geometric mean anti-tetanus titers compared to those of the HIV-unexposed infants. Our data point to the necessity of evaluating vaccine immune responses in these children and reinforced that alterations in lymphocyte numbers and functions reported for newborns from HIV-infected mothers interfere with the vaccine response.
Antibody Profiling of Borrelia burgdorferi Infection in Horses
Authors: Burbelo Peter D. , Bren Kathleen E. , Ching Kathryn H. , Coleman Adam , Yang Xiuli , Kariu Toru , Iadarola Michael J. , Pal Utpal 
Published: July 2011

ABSTRACTInfection withBorrelia burgdorferiis common in horses and ponies from the New England and mid-Atlantic regions of the United States. Here, we evaluated luciferase immunoprecipitation systems (LIPS) for profiling antibody responses against three different antigenic targets for the diagnosis of equineB. burgdorferiinfection. LIPS testing of horse serum samples suspected of Lyme infection revealed that approximately 75% of the horse samples (114/159) were seropositive against the synthetic VOVO antigen, comprising repeated immunodominant C6 epitopes as well as OspC immunodominant epitopes. A comparison of VOVO and immunofluorescence assays (IFA) showed that 51% of the samples were positive in both assays (VOVO+/IFA+), 13% were VOVO−/IFA+, 21% were VOVO+/IFA−, and 15% were negative in both. To further understand humoral responses toB. burgdorferiand reconcile the diagnostic differences between IFA and VOVO, two additionalB. burgdorferiLIPS tests were performed with DbpA and DbpB. Robust seropositive antibody responses against DbpA and/or DbpB were detected in 98% (79/81) of the VOVO+/IFA+and 93% (50/54) of the discrepant samples. Additionally, some of the samples negative by both VOVO and IFA showed immunoreactivity against DbpA and/or DbpB. Overall, 94% of the suspected horse samples were seropositive by LIPS, and heat map analysis revealed that seropositive samples often were immunoreactive with at least two of the three antigens. These results suggest that LIPS tests employing multiple recombinant antigens offer a promising approach for the evaluation of antibody responses in Lyme disease.
Epidemiology and Evolutionary Characteristics of the Porcine Reproductive and Respiratory Syndrome Virus in China between 2006 and 2010
Authors: Li Bin , Fang Liurong , Guo Xueliang , Gao Jianfeng , Song Tao , Bi Jing , He Kongwang , Chen Huanchun , Xiao Shaobo 
Published: July 2011

ABSTRACTIn 2006, an emerging highly pathogenic strain of porcine reproductive and respiratory syndrome virus (PRRSV), which causes continuous high fever and a high proportion of deaths in vaccinated pigs of all ages, broke out in mainland China and spread rapidly to neighboring countries. To examine the epidemiology and evolutionary characteristics of Chinese PRRSV after the 2006 outbreak, we tested 2,981 clinical samples collected from 2006 to 2010 in China, determined 153 Nsp2 sequences and 249 ORF5 sequences, and analyzed the epidemiology and genetic diversity of Chinese PRRSV. Our results showed that the percentage of PRRSV-positive specimens collected from sick pigs averaged 60.85% in the past 5 years and that the highly pathogenic PRRSV has become the dominant strain in China. Furthermore, a reemerging strain which apparently evolved from the highly pathogenic PRRSV strain in 2006 appeared to be widely prevalent in China from 2009 onwards. Sequence analyses revealed that the hypervariable region of Nsp2 in most of the isolates contained a discontinuous deletion equivalent to 30 amino acids, along with other types of deletions. Extensive amino acid substitutions in the GP5 sequence translated from ORF5 were found, particularly in the potential neutralization epitope and the N-glycosylation sites. Our results suggest that Chinese PRRSV has undergone rapid evolution and can circumvent immune responses induced by currently used vaccines. Information from this study will help in understanding the evolutionary characteristics of Chinese PRRSV and assist ongoing efforts to develop and use PRRSV vaccines in the future.
Clostridium clostridioforme and Atopobium minutum Clinical Isolates with VanB-Type Resistance in France
Authors: Marvaud Jean-Christophe , Mory Francine , Lambert Thierry 
Published: July 2011

ABSTRACT

Acquired vancomycin resistance in Gram-positive anaerobes has been reported only in Australia and Canada from rare
vanB
-positive stool samples in the absence of vancomycin-resistant enterococci (VRE). We report the emergence of VanB-type resistance in
Clostridium clostridioforme
and
Atopobium minutum
involved in human infections in France.
A Novel Eukaryote-Made Thermostable DNA Polymerase Which Is Free from Bacterial DNA Contamination
Authors: Niimi Hideki , Mori Masashi , Tabata Homare , Minami Hiroshi , Ueno Tomohiro , Hayashi Shirou , Kitajima Isao 
Published: July 2011

ABSTRACT

To achieve the production of a thermostable DNA polymerase free from bacterial DNA contamination, we developed eukaryote-made thermostable DNA (
Taq
) polymerase. The novel eukaryote-made thermostable DNA polymerase resolves the problem of contaminating bacterial DNA in conventional bacterially made thermostable DNA polymerase as a result of its manufacture and incomplete purification. Using eukaryote-made thermostable DNA polymerase, the sensitive and reliable detection of bacteria becomes feasible for large fields, thereby making the development of a wide range of powerful applications possible.
Evaluation and Verification of the Seeplex Diarrhea-V ACE Assay for Simultaneous Detection of Adenovirus, Rotavirus, and Norovirus Genogroups I and II in Clinical Stool Specimens
Authors: Higgins Rachel R. , Beniprashad Melissa , Cardona Mark , Masney Steven , Low Donald E. , Gubbay Jonathan B. 
Published: July 2011

ABSTRACT
Acute viral gastroenteritis is an intestinal infection that can be caused by several different viruses. Here we describe the evaluation and verification of Seeplex Diarrhea-V ACE (Seeplex DV), a novel commercial multiplex reverse transcription-PCR (RT-PCR) assay that detects 5 diarrheal pathogens, including adenovirus, rotavirus, norovirus genogroup I (GI) and GII, and astrovirus. We describe a retrospective study of 200 clinical specimens of which 177 were stool specimens previously tested for the presence of gastrointestinal viruses by electron microscopy (EM) and/or real-time RT-PCR (rRT-PCR). The remaining 23 specimens comprised other human pathogens of viral or bacterial origin. Discordant norovirus GI and GII results were resolved using a commercial kit; discordant adenovirus and rotavirus results were resolved using a home brew multiplex rRT-PCR assay. Diagnostic sensitivities and specificities were calculated before and after discordant analysis. After discordant analysis, estimated diagnostic sensitivities were 100% for adenovirus, rotavirus, and norovirus GI and 97% for norovirus GII. Diagnostic specificities after discordant analysis were 100% for adenovirus, rotavirus, and norovirus GI and 99.4% for norovirus GII. The 95% limits of detection were 31, 10, 2, and 1 genome equivalent per reaction for adenovirus, rotavirus, and norovirus GI and GII, respectively. The results demonstrate that the Seeplex DV assay is sensitive, specific, convenient, and reliable for the simultaneous detection of several viral pathogens directly in specimens from patients with gastroenteritis. Importantly, this novel multiplex PCR assay enabled the identification of viral coinfections in 12 (6.8%) stool specimens.
Increased Mortality in Young Candidemia Patients Associated with Presence of a Candida albicans General-Purpose Genotype
Authors: Schmid J. , Tortorano A. M. , Jones G. , Lazzarini C. , Zhang N. , Bendall M. J. , Cogliati M. , Wattimena S. , Klingspor L. ,   ECMM Survey,   French Mycoses Study Group
Published: July 2011

ABSTRACT

The yeast
Candida albicans
causes life-threatening candidemia. A general-purpose genotype (GPG; corresponds to clade 1) causes more infections than other
C. albicans
genotypes. To investigate if GPG strains also cause higher mortality, we developed a duplex PCR assay which was 98% accurate in identifying GPG strains in an international collection of strains typed with probe Ca3. We applied the assay to 635 European
C. albicans
candidemia isolates. Of these, 18% conformed to the GPG genotype, 4% were of a borderline genotype, and 78% were of a non-GPG genotype, broadly consistent with genotype distributions in earlier studies. The prevalence of GPG strains was increased in females and in younger patients, exceeding 40% in infants aged ≤1 year. Logistic regression confirmed sex and age as significant determinants of GPG prevalence. Across the entire patient cohort, there was no difference in mortality for patients infected with GPG strains or other strains (36% versus 37%). However, mortality in patients aged ≤48 years was 33% for infection with GPG strains but only 15% for infection with other strains (
z
test;
P
< 0.01). Mortality rates associated with GPG and non-GPG strains were comparable in older patients (39% versus 46%). A logistic regression analysis confirmed the age-dependent impact of genotype on mortality. Thus, GPG strains may be more virulent than other strains in younger patients. Because candidemia is usually caused by endogenous strains, our PCR assay could potentially be used as a risk assessment tool for identifying younger patients most at risk of death from candidemia.
Detection of Extended-Spectrum-β-Lactamase-Positive Escherichia coli in Bile Isolates from Two Dogs with Bacterial Cholangiohepatitis
Authors: Timofte Dorina , Dandrieux Julien , Wattret Andrew , Fick Jenny , Williams Nicola J. 
Published: July 2011

ABSTRACTThis is the first report ofEscherichia coliisolates producing CTX-M-15, the predominant type of extended-spectrum β-lactamase (ESBL) associated with clinical disease in humans in the United Kingdom, in a United Kingdom pet dog. This report also describes the first isolation of CTX-M/Tem ESBL-positiveE. colifrom bile in dogs with hepatobiliary disease.
Retrospective and Prospective Verification of the Cepheid Xpert Influenza Virus Assay
Authors: Popowitch Elena B. , Rogers Elaine , Miller Melissa B. 
Published: July 2011

ABSTRACT

We performed a retrospective (
n
= 121) and prospective (
n
= 305) verification of the Cepheid Xpert Flu assay to determine its performance characteristics. The overall sensitivity and specificity were 93% and 100%, respectively. Nasopharyngeal specimen sensitivities were 100% for seasonal influenza A/H1 virus and influenza A/H3 virus, 90% for influenza A/2009/H1N1 virus, and 95% for influenza B virus.
Pseudomonas aeruginosa Endophthalmitis after Penetrating Keratoplasty Transmitted from the Same Donor to Two Recipients Confirmed by Pulsed-Field Gel Electrophoresis
Authors: Oguido Ana Paula Miyagusko Taba , Casella Antonio Marcelo Barbante , Hofling-Lima Ana Luisa , Pacheco Sergio Arruda , Bispo Paulo José Martins , Marques Fernanda 
Published: July 2011

ABSTRACT

Two devastating cases of multidrug-resistant
Pseudomonas aeruginosa
endophthalmitis after keratoplasty as the result of transmission from the same donor were confirmed by pulsed-field gel electrophoresis. Strategies for preventing donor-to-host transmission, such as the use of antimicrobial agents of greater efficacy and better methods for detecting microorganisms in preservation medium, could minimize this type of transmission.