bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of head size/shape, miscentering, and bowtie filter on peak patient tissue doses from modern brain perfusion 256‐slice CT: How can we minimize the risk for deterministic effects?
Authors: Perisinakis Kostas , Seimenis Ioannis , Tzedakis Antonis , Papadakis Antonios E. , Damilakis John 
Published: January 2013

Purpose:To determine patient‐specific absorbed peak doses to skin, eye lens, brain parenchyma, and cranial red bone marrow (RBM) of adult individuals subjected to low‐dose brain perfusion CT studies on a 256‐slice CT scanner, and investigate the effect of patient head size/shape, head position during the examination and bowtie filter used on peak tissue doses.Methods:The peak doses to eye lens, skin, brain, and RBM were measured in 106 individual‐specific adult head phantoms subjected to the standard low‐dose brain perfusion CT on a 256‐slice CT scanner using a novel Monte Carlo simulation software dedicated for patient CT dosimetry. Peak tissue doses were compared to corresponding thresholds for induction of cataract, erythema, cerebrovascular disease, and depression of hematopoiesis, respectively. The effects of patient head size/shape, head position during acquisition and bowtie filter used on resulting peak patient tissue doses were investigated. The effect of eye‐lens position in the scanned head region was also investigated. The effect of miscentering and use of narrow bowtie filter on image quality was assessed.Results:The mean peak doses to eye lens, skin, brain, and RBM were found to be 124, 120, 95, and 163 mGy, respectively. The effect of patient head size and shape on peak tissue doses was found to be minimal since maximum differences were less than 7%. Patient head miscentering and bowtie filter selection were found to have a considerable effect on peak tissue doses. The peak eye‐lens dose saving achieved by elevating head by 4 cm with respect to isocenter and using a narrow wedge filter was found to approach 50%. When the eye lies outside of the primarily irradiated head region, the dose to eye lens was found to drop to less than 20% of the corresponding dose measured when the eye lens was located in the middle of the x‐ray beam. Positioning head phantom off‐isocenter by 4 cm and employing a narrow wedge filter results in a moderate reduction of signal‐to‐noise ratio mainly to the peripheral region of the phantom.Conclusions:Despite typical peak doses to skin, eye lens, brain, and RBM from the standard low‐dose brain perfusion 256‐slice CT protocol are well below the corresponding thresholds for the induction of erythema, cataract, cerebrovascular disease, and depression of hematopoiesis, respectively, every effort should be made toward optimization of the procedure and minimization of dose received by these tissues. The current study provides evidence that the use of the narrower bowtie filter available may considerably reduce peak absorbed dose to all above radiosensitive tissues with minimal deterioration in image quality. Considerable reduction in peak eye‐lens dose may also be achieved by positioning patient head center a few centimeters above isocenter during the exposure.
Correction factors for ionization chamber dosimetry in CyberKnife: Machine‐specific, plan‐class, and clinical fields
Authors: Gago‐Arias Araceli , Antolín Elena , Fayos‐Ferrer Francisco , Simón Rocío , González‐Castaño Diego M. , Palmans Hugo , Sharpe Peter , Gómez Faustino , Pardo‐Montero Juan 
Published: January 2013

Purpose:The aim of this work is the application of the formalism for ionization chamber reference dosimetry of small and nonstandard fields [R. Alfonso, P. Andreo, R. Capote, M. S. Huq, W. Kilby, P. Kjäll, T. R. Mackie, H. Palmans, K. Rosser, J. Seuntjens, W. Ullrich, and S. Vatnitsky, “A new formalism for reference dosimetry of small and nonstandard fields,” Med. Phys. 35, – (2008)] 10.1118/1.3005481 to the CyberKnife robotic radiosurgery system. Correction factors for intermediate calibration fields, a machine‐specific reference field (msr) and two plan‐class specific reference fields (pcsr), have been studied. Furthermore, the applicability of the new formalism to clinical dosimetry has been analyzed through the investigation of two clinical treatments.Methods:PTW31014 and Scanditronix‐Wellhofer CC13 ionization chamber measurements were performed for the fields under investigation. Absorbed dose to water was determined using alanine reference dosimetry, and experimental correction factors were calculated from alanine to ionization chamber readings ratios. In addition, correction factors were calculated for the intermediate calibration fields and one of the clinical treatment fields using the Monte Carlo method and these were compared with the experimental values.Results:Overall correction factors deviating from unity by approximately 2% were obtained from both measurements and simulations, with values below and above unity for the studied intermediate calibration fields and clinical fields for the ionization chambers under consideration. Monte Carlo simulations yielded correction factors comparable with those obtained from measurements for the machine‐specific reference field, although differences from 1% to 3.3% were observed between measured and calculated correction factors for the composite intermediate calibration fields. Dose distribution inhomogeneities are thought to be responsible for such discrepancies.Conclusions:The differences found between overall correction factors associated with the proposed intermediate calibration fields and the clinical fields under investigation show that depending on the clinical field and the detector used, either a machine‐specific reference field or a plan‐class specific reference field is more representative for the clinical field. Given the experimental and numerical uncertainties and the small number of clinical fields considered in this study the significance of these observations is limited and it remains unclear for the CyberKnife if there would be a significant gain in using a pcsr field rather than a msr field as reference field for relative dosimetry.
Predictive Models for Escherichia coli Concentrations at Inland Lake Beaches and Relationship of Model Variables to Pathogen Detection
Authors: Francy Donna S. , Stelzer Erin A. , Duris Joseph W. , Brady Amie M. G. , Harrison John H. , Johnson Heather E. , Ware Michael W. 
Published: January 2013

ABSTRACT

Predictive models, based on environmental and water quality variables, have been used to improve the timeliness and accuracy of recreational water quality assessments, but their effectiveness has not been studied in inland waters. Sampling at eight inland recreational lakes in Ohio was done in order to investigate using predictive models for
Escherichia coli
and to understand the links between
E. coli
concentrations, predictive variables, and pathogens. Based upon results from 21 beach sites, models were developed for 13 sites, and the most predictive variables were rainfall, wind direction and speed, turbidity, and water temperature. Models were not developed at sites where the
E. coli
standard was seldom exceeded. Models were validated at nine sites during an independent year. At three sites, the model resulted in increased correct responses, sensitivities, and specificities compared to use of the previous day's
E. coli
concentration (the current method). Drought conditions during the validation year precluded being able to adequately assess model performance at most of the other sites.
Cryptosporidium
, adenovirus,
eaeA
(
E. coli
),
ipaH
(
Shigella
), and
spvC
(
Salmonella
) were found in at least 20% of samples collected for pathogens at five sites. The presence or absence of the three bacterial genes was related to some of the model variables but was not consistently related to
E. coli
concentrations. Predictive models were not effective at all inland lake sites; however, their use at two lakes with high swimmer densities will provide better estimates of public health risk than current methods and will be a valuable resource for beach managers and the public.
Efficient Colonization of the Bean Bug Riptortus pedestris by an Environmentally Transmitted Burkholderia Symbiont
Authors: Kikuchi Yoshitomo , Yumoto Isao 
Published: January 2013

ABSTRACT

The bean bug
Riptortus pedestris
is specifically associated with the
Burkholderia
gut symbiont and acquires the symbiont from the environment every generation. Here, we investigated the infective dose of the symbiont by experimental administration. The 50% infective dose was remarkably low, only 80 cells, indicating efficient colonization of the symbiont.
Survival of Escherichia coli O157:H7 in Soils from Vegetable Fields with Different Cultivation Patterns
Authors: Yao Zhiyuan , Wei Gang , Wang Haizhen , Wu Laosheng , Wu Jianjun , Xu Jianming 
Published: January 2013

ABSTRACT

Escherichia coli
O157:H7 survived longer in soils from plastic-greenhouse cultivation than soils from the open field. Soil pH, organic carbon levels, and the ratio of bacterial phospholipid fatty acids (PLFAs) to fungal PLFAs played the significant roles in survival of O157:H7. Greater attention should be paid to the control of pathogen contamination under conditions of plastic-greenhouse cultivation.
Xylanase Gene Transcription in Trichoderma reesei Is Triggered by Different Inducers Representing Different Hemicellulosic Pentose Polymers
Authors: Herold Silvia , Bischof Robert , Metz Benjamin , Seiboth Bernhard , Kubicek Christian P. 
Published: January 2013

ABSTRACTThe ascomyceteTrichoderma reeseiis a paradigm for the regulation and production of plant cell wall-degrading enzymes, including xylanases. Four xylanases, including XYN1 and XYN2 of glycosyl hydrolase family 11 (GH11), the GH10 XYN3, and the GH30 XYN4, were already described. By genome mining, we identified a fifth xylanase, XYN5, belonging to GH11. Transcriptional analysis reveals that the expression of all xylanases butxyn3is induced byd-xylose, dependent on the cellulase and xylanase regulator XYR1 and negatively regulated by the carbon catabolite repressor CRE1. Impairment ofd-xylose catabolism at thed-xylose reductase and xylitol dehydrogenase step strongly enhanced induction byd-xylose. Knockout of thel-xylulose reductase-encoding genelxr3, which connects thed-xylose andl-arabinose catabolic pathways, had no effect on xylanase induction. Besides the induction byd-xylose, theT. reeseixylanases were also induced byl-arabinose, and this induction was also enhanced in knockout mutants inl-arabinose reductase (xyl1),l-arabitol dehydrogenase (lad1), andl-xylulose reductase (lxr3). Induction byl-arabinose was also XYR1 dependent. Analysis of intracellular polyols revealed accumulation of xylitol in all strains only during incubation withd-xylose and accumulation ofl-arabitol only during incubation withl-arabinose. Induction byl-arabinose could be further stimulated by addition ofd-xylose. We conclude that the expression of theT. reeseixylanases can be induced by bothd-xylose andl-arabinose, but independently of each other and by using different inducing metabolites.
Complete Genome Sequences from Three Genetically Distinct Strains Reveal High Intraspecies Genetic Diversity in the Microsporidian Encephalitozoon cuniculi
Authors: Pombert Jean-François , Xu Jinshan , Smith David R. , Heiman David , Young Sarah , Cuomo Christina A. , Weiss Louis M. , Keeling Patrick J. 
Published: January 2013

ABSTRACT

Microsporidia from the Encephalitozoonidae are obligate intracellular parasites with highly conserved and compacted nuclear genomes: they have few introns, short intergenic regions, and almost identical gene complements and chromosome arrangements. Comparative genomics of
Encephalitozoon
and microsporidia in general have focused largely on the genomic diversity between different species, and we know very little about the levels of genetic diversity within species. Polymorphism studies with
Encephalitozoon
are so far restricted to a small number of genes, and a few genetically distinct strains have been identified; most notably, three genotypes (ECI, ECII, and ECIII) of the model species
E. cuniculi
have been identified based on variable repeats in the rRNA internal transcribed spacer (ITS). To determine if
E. cuniculi
genotypes are genetically distinct lineages across the entire genome and at the same time to examine the question of intraspecies genetic diversity in microsporidia in general, we sequenced
de novo
genomes from each of the three genotypes and analyzed patterns of single nucleotide polymorphisms (SNPs) and insertions/deletions across the genomes. Although the strains have almost identical gene contents, they harbor large numbers of SNPs, including numerous nonsynonymous changes, indicating massive intraspecies variation within the Encephalitozoonidae. Based on this diversity, we conclude that the recognized genotypes are genetically distinct and propose new molecular markers for microsporidian genotyping.
The role of chief executive officers in a quality improvement initiative: a qualitative study
Authors: Parand Anam , Dopson Sue , Vincent Charles 
Published: January 2013

ObjectivesTo identify the critical dimensions of hospital Chief Executive Officers’ (CEOs) involvement in a quality and safety initiative and to offer practical guidance to assist CEOs to fulfil their leadership role in quality improvement (QI).DesignQualitative interview study.Setting20 organisations participating in the main phase of the Safer Patients Initiative (SPI) programme across the UK.Participants17 CEOs overseeing 19 organisations participating in the main phase of the SPI programme and 36 staff (20 workstream leads, 10 coordinators and 6 managers) involved in SPI across all 20 participating organisations.Main outcome measureSelf-reported perceptions of CEOs on their contribution and involvement within the SPI programme, supplemented by staff peer-reports.ResultsThe CEOs recognised the importance of their part in the SPI programme and gave detailed accounts of the perceived value that their involvement had brought at all stages of the process. In exploring the parts played by the CEOs, five dimensions were identified: (1) resource provision; (2) staff motivation and engagement; (3) commitment and support; (4) monitoring progress and (5) embedding programme elements. Staff reports confirmed these dimensions; however, the weighting of the dimensions differed. The findings stress the importance of particular actions of support and monitoring such as constant communication through leadership walk rounds and reviewing programme progress and its related clinical outcomes at Board meetings.ConclusionsThis study addressed the call for more research-informed practical guidance on the role of senior management in QI initiatives. The findings show that the CEOs provided key participation considered to significantly contribute towards the SPI programme. CEOs and staff identified a number of clear and consistent themes essential to organisation safety improvement. Queries raised include the tangible benefits of executive involvement in changing structures and embedding for sustainability and the practical steps to creating the ‘right’ environment for QI.
A public opinion survey: is presumed consent the answer to kidney shortage in Hong Kong?
Authors: Chan Tak Kwong , Cowling Benjamin John , Tipoe George Lim 
Published: January 2013

ObjectiveTo project the impact of an opt-out system (presuming consent) in Hong Kong on the likelihood that a potential donor donates his or her kidneys after death and the likelihood of violating a potential donor's autonomy.SettingCross-sectional population-based anonymous telephone survey.ParticipantsRandom sample of 802 adults aged between 18 and 64.Main outcome measureWillingness to donate their own kidneys after death and their willingness to donate the kidneys of a deceased family member in different hypothetical situations under the current opt-in system and under our proposed soft version of an opt-out system.ResultsWhen the wish of the deceased is unknown, 72.6% (n=583) of the respondents said that under the proposed opt-out system, they would definitely or likely consent to donating the kidneys of a deceased family member, significantly more than under the current opt-in system (OR 2.53, 95% CI 2.06 to 3.11). An opt-out system could significantly improve the projected overall donation potential from 0.631 to 0.771 (OR 1.97, 95% CI 1.58–2.45) and reduce the projected overall chance of violating the autonomy of a potential donor from 0.292 to 0.127 (OR 0.35, 95% CI 0.27 to 0.45).ConclusionsA switch to an opt-out system in Hong Kong would likely result in the wishes of more people being followed and raise the overall cadaveric kidney donation rate.
Use of non-steroidal anti-inflammatory drugs and proton pump inhibitors in correlation with incidence, recurrence and death of peptic ulcer bleeding: an ecological study
Authors: Lu Yunxia , Sverdén Emma , Ljung Rickard , Söderlund Claes , Lagergren Jesper 
Published: January 2013

BackgroundNon-steroidal anti-inflammatory drugs (NSAIDs) and proton pump inhibitors (PPIs) are regarded as two types of drugs that respectively increase and decrease the risk of peptic ulcer bleeding. However, their relation to occurrence, recurrence and death of bleeding in the population level is not clear.Study objectiveTo clarify recent calendar-time correlations between sales of NSAIDs and PPIs and the occurrence of peptic ulcer bleeding, re-bleeding and death.DesignEcological study.ResultsThe time trend of peptic ulcer bleeding did not correlate with PPI sales but did correlate with NSAIDs in mem (Rmale=0.6571, Pmale=0.05). Sales of PPIs (inverse) and NSAIDs correlated with re-bleeding in women (Rmale=−0.8754, Pmale=0.002 and Rfemale=0.7161, Pfemale=0.03, respectively), but not in men. An inverse correlation between PPI sales and 30-day death after bleeding was found (Rmale=−0.9392, Pmale=0.0002 and Rfemale=−0.8561, Pfemale=0.003), and NSAID sales were found to correlate with increased death after bleeding ((Rmale=0.7278, Pmale=0.03, Rfemale=0.7858, Pfemale=0.01).ConclusionsThe sales of NSAIDs and PPIs correlate with recurrence of peptic ulcer bleeding in women and death after peptic ulcer bleeding in both genders in the population level.
Independent association between low serum amylase and non-alcoholic fatty liver disease in asymptomatic adults: a cross-sectional observational study
Authors: Nakajima Kei , Oshida Haruki , Muneyuki Toshitaka , Saito Masafumi , Hori Yumiko , Fuchigami Hiroshi , Kakei Masafumi , Munakata Hiromi 
Published: January 2013

ObjectivesLow serum amylase (LSA) was reported to be associated with obesity, metabolic syndrome (MetS) and diabetes. However, it is unknown as to whether LSA is associated with non-alcoholic fatty liver disease (NAFLD), a hepatic manifestation of MetS and insulin resistance. Therefore, we performed a clinical epidemiological study to investigate this potential association.DesignA cross-sectional observational study with multivariate analysis.SettingSubjects were recruited in a healthcare centre in Saitama, an eastern district of Japan, near Tokyo.ParticipantsA total of 1475 asymptomatic adults aged 30–79 years who underwent detailed medical check-ups and who regularly consumed small amounts of alcohol (<20 g/day).Outcome measuresSerum amylase, cardiometabolic risk factors, NAFLD determined by ultrasound, MetS determined by Adult Treatment Panel-III criteria and diabetes were assessed.ResultsThe prevalence of NAFLD increased significantly from 22.5% to 42.4% (all grades) and from 9.2% to 24.0% (moderate or severe grade) from the highest to the lowest quartile of serum amylase. Multiple logistic regression analysis showed that, compared with the highest quartile of serum amylase, the lowest quartile of serum amylase was significantly associated with any-grade NAFLD and with moderate-to-severe NAFLD, even after adjusting for MetS or diabetes. The association between LSA and any-grade NAFLD disappeared after further adjustment for body mass index or waist circumference, whereas the association between LSA and moderate or severe NAFLD remained statistically significant (ORs (95%CI), 2.01 (1.07 to 3.78) and 2.06 (1.09 to 3.87), respectively, both p=0.01).ConclusionsOur results suggest that LSA may be associated with moderate or severe NAFLD in asymptomatic adults independent of MetS, diabetes and obesity. These results warrant confirmation in further studies.
Leaders’ and followers’ individual experiences during the early phase of simulation-based team training: an exploratory study
Authors: Meurling Lisbet , Hedman Leif , Felländer-Tsai Li , Wallin Carl-Johan 
Published: January 2013

BackgroundA growing body of evidence shows that team training can develop essential team skills and contribute to better patient outcomes. Current simulation-based team training (SBTT) programmes most often include targets and feedback focused on the whole team and/or leader, ignoring the follower as a unique entity. By considering followers’ individual experiences, and tailoring behavioural targets for training and feedback, SBTT could be improved. Our aim was to explore the individual experiences and behaviours of leaders and followers during the early phase of SBTT, and we hypothesised that leaders and followers would show different responses.MethodsMedical students (n=54) participated in half-day SBTT including three video-recorded scenarios. Self-efficacy was assessed pretraining and post-training. For each scenario (n=36), the individual teamwork behaviours, concentration, mental strain and the team's clinical performance were recorded. Data were analysed using a mixed model allowing for participants to be their own control in their roles as leader or follower.ResultsSelf-efficacy improved. In the role of leader, participants communicated to a greater extent and experienced higher mental strain and concentration than they did in the role of follower.DiscussionThe increased self-efficacy enables a positive learning outcome after only three scenarios. Individual experiences and behaviours differed between the role of leader and that of follower. By shedding further light on leaders’ and followers’ individual experiences and behaviours, targets for training and feedback could be specified in order to improve SBTT.
Frequency of Myocardial Infarction and Its Relationship to Angiographic Collateral Flow in Territories Supplied by Chronically Occluded Coronary Arteries
Authors: Choi Jin-Ho , Chang Sung-A , Choi Jin-Oh , Song Young Bin , Hahn Joo-Yong , Choi Seung Hyuk , Lee Sang-Chol , Lee Sang-Hoon , Oh Jae K. , Choe YeonHyeon , Gwon Hyeon-Cheol 
Published: January 2013

Background—
Despite complete interruption of antegrade coronary artery flow in the setting of a chronic total occlusion (CTO), clinical recognition of myocardial infarction is often challenging. Using cardiac MRI, we investigated the frequency and extent of myocardial infarction in patients with CTO, and assessed their relationship with regional systolic function and the extent of angiographic collateral flow.

Methods and Results—

We included 170 consecutive patients (median age, 62 years) with angiographically documented CTO. Regional late gadolinium enhancement and wall motion score index were assessed by cardiac MRI with the use of a 17-segment model. Angiographic collateral flow was assessed by the collateral connection grade and the Rentrop score. Evidence of previous myocardial infarction was found in 25% of patients by ECG Q waves, in 69% by regional wall motion abnormality, and in 86% of patients by late gadolinium enhancement. Increased angiographic collateral flow was associated with a lower frequency of Q waves on ECG, and a lower regional wall motion score index, late gadolinium enhancement volume (%), and degree of late gadolinium enhancement transmurality (all
P
<0.001), as well.

Conclusions—
The frequency of myocardial infarction in territories subtended by CTO is significantly higher than previously recognized. The degree of myocardial injury downstream epicardial CTO is inversely correlated with the degree of angiographic collaterals.