bluuebunny/crossref_metadata_2025_split huggingface dataset:
PShield: An exact three‐dimensional numerical solution for determining optimal shielding designs for PET/CT facilities
Authors: Pasciak Alexander S. , Jones A. Kyle 
Published: May 2012

Purpose:Calculation of radiation shielding requirements for high‐workload positron emission tomography/computed tomography (PET/CT) installations using the methods proposed by Task Group 108 (TG 108) of the American Association of Physicists in Medicine can be a complex task. The principal challenge that makes PET shielding design more complex than other diagnostic imaging modalities, aside from the higher photon energy, is that it is a multisource problem for which no unique solution exists. Although many solutions may meet shielding design dose limits, each solution has a different cost for materials and construction according to the type, thickness, weight, and location of the specified shielding. Here, the authors describe PShield, an algorithm that incorporates three‐dimensional (3D) numerical methods to optimize PET shielding and delivers a cost‐optimized solution while making no approximations.Methods:The PShield algorithm uses a sequential quadratic programming routine to optimize PET shielding by minimizing a cost function in three‐dimensions using extrapolations of the formulas published by TG 108. PShield makes no approximations and accounts for the contribution of every radiation source to the dose rate at every location in the problem using a discrete mesh. The authors used two simple examples of shielding problems to compare PShield with the TG 108 methods.Results:The benefit of applying an optimization routine to an indeterminate problem is the identification of the only solution to the problem that minimizes the desired cost function. Choosing a poorly optimized solution can result in a shielding design that requires more shielding than an optimized design to reach the same dose rate at a given control point. The increased accuracy afforded by PShield ensures that dose rates at every point in a control area never exceed the design dose, whereas approximations often used to evaluate TG 108 methods may result in hot spots where the dose rate exceeds the design dose.Conclusions:The PShield algorithm is an exact 3D numerical solution for optimal PET/CT shielding based on the methods proposed by TG 108. Selection of the optimum shielding design can minimize the total material cost and structural burden of installed shielding or achieve other goals desired by a specific site. This is especially important for modern PET/CT suites, where increases in scanner capabilities have resulted in more complex shielding problems and the potential for high occupational doses.
Influence of robust optimization in intensity‐modulated proton therapy with different dose delivery techniques
Authors: Liu Wei , Li Yupeng , Li Xiaoqiang , Cao Wenhua , Zhang Xiaodong 
Published: May 2012

Purpose:The distal edge tracking (DET) technique in intensity‐modulated proton therapy (IMPT) allows for high energy efficiency, fast and simple delivery, and simple inverse treatment planning; however, it is highly sensitive to uncertainties. In this study, the authors explored the application of DET in IMPT (IMPT‐DET) and conducted robust optimization of IMPT‐DET to see if the planning technique's sensitivity to uncertainties was reduced. They also compared conventional and robust optimization of IMPT‐DET with three‐dimensional IMPT (IMPT‐3D) to gain understanding about how plan robustness is achieved.Methods:They compared the robustness of IMPT‐DET and IMPT‐3D plans to uncertainties by analyzing plans created for a typical prostate cancer case and a base of skull (BOS) cancer case (using data for patients who had undergone proton therapy at our institution). Spots with the highest and second highest energy layers were chosen so that the Bragg peak would be at the distal edge of the targets in IMPT‐DET using 36 equally spaced angle beams; in IMPT‐3D, 3 beams with angles chosen by a beam angle optimization algorithm were planned. Dose contributions for a number of range and setup uncertainties were calculated, and a worst‐case robust optimization was performed. A robust quantification technique was used to evaluate the plans' sensitivity to uncertainties.Results:With no uncertainties considered, the DET is less robust to uncertainties than is the 3D method but offers better normal tissue protection. With robust optimization to account for range and setup uncertainties, robust optimization can improve the robustness of IMPT plans to uncertainties; however, our findings show the extent of improvement varies.Conclusions:IMPT's sensitivity to uncertainties can be improved by using robust optimization. They found two possible mechanisms that made improvements possible: (1) a localized single‐field uniform dose distribution (LSFUD) mechanism, in which the optimization algorithm attempts to produce a single‐field uniform dose distribution while minimizing the patching field as much as possible; and (2) perturbed dose distribution, which follows the change in anatomical geometry. Multiple‐instance optimization has more knowledge of the influence matrices; this greater knowledge improves IMPT plans' ability to retain robustness despite the presence of uncertainties.
Genome Sequence of Shigella flexneri Serotype 5a Strain M90T Sm
Authors: Onodera Naoko T. , Ryu Julie , Durbic Tanja , Nislow Corey , Archibald John M. , Rohde John R. 
Published: May 2012

ABSTRACT

Bacteria of the genus
Shigella
are a major cause of death worldwide (L. von Seidlein et al., PLoS Med. 3:e353, 2006). We sequenced the genome of
Shigella flexneri
strain M90T Sm (serotype 5a) and compared it to the published genome sequence of
S. flexneri
strain 8401 (serotype 5b).
Draft Genome of a Brazilian Avian-Pathogenic Escherichia coli Strain and
In Silico
Characterization of Virulence-Related Genes
Authors: Rojas Thaís Cabrera Galvão , Parizzi Lucas Pedersen , Tiba Monique Ribeiro , Chen Lihong , Pereira Gonçalo Amarante Guimarães , Sangal Vartul , Yang Jian , Yu Jun , Dias da Silveira Wanderley 
Published: May 2012

ABSTRACT

Avian-pathogenic
Escherichia coli
(APEC) strains cause extraintestinal diseases in avian species. Here, we present the draft genome of an APEC strain (SCI-07) from Brazil that was isolated from skin lesions (gelatinous edema) on the head and periorbital tissues of a laying hen with swollen head syndrome.
Genome Sequence of Sphingomonas sp. Strain PAMC 26621, an Arctic-Lichen-Associated Bacterium Isolated from a Cetraria sp
Authors: Lee Hyoungseok , Shin Seung Chul , Lee Jungeun , Kim Su Jin , Kim Bum-Keun , Hong Soon Gyu , Kim Eun Hye , Park Hyun 
Published: May 2012

ABSTRACT

The lichen-associated bacterial strain
Sphingomonas
sp. PAMC 26621 was isolated from an Arctic lichen
Cetraria
sp. on Svalbard Islands. Here we report the draft genome sequence of this strain, which could provide novel insights into the molecular principles of lichen-microbe interactions.
Draft Genome Sequences of the Diarrheagenic Escherichia coli Collection
Authors: Hazen Tracy H. , Sahl Jason W. , Redman Julia C. , Morris Carolyn R. , Daugherty Sean C. , Chibucos Marcus C. , Sengamalay Naomi A. , Fraser-Liggett Claire M. , Steinsland Hans , Whittam Thomas S. , Whittam Beth , Manning Shannon D. , Rasko David A. 
Published: May 2012

ABSTRACT

We report the draft genome sequences of the collection referred to as the
Escherichia coli
DECA collection, which was assembled to contain representative isolates of the 15 most common diarrheagenic clones in humans (
http://shigatox.net/new/
). These genomes represent a valuable resource to the community of researchers who examine these enteric pathogens.
An evaluation of the effectiveness and cost effectiveness of the National Exercise Referral Scheme in Wales, UK: a randomised controlled trial of a public health policy initiative
Authors: Murphy Simon Mark , Edwards Rhiannon Tudor , Williams Nefyn , Raisanen Larry , Moore Graham , Linck Pat , Hounsome Natalia , Din Nafees Ud , Moore Laurence 
Published: May 2012

BackgroundThe Wales National Exercise Referral Scheme (NERS) is a 16-week programme including motivational interviewing, goal setting and relapse prevention.MethodA pragmatic randomised controlled trial with nested economic evaluation of 2160 inactive participants with coronary heart disease risk (CHD, 1559, 72%), mild to moderate depression, anxiety or stress (79, 4%) or both (522, 24%) randomised to receive (1) NERS or (2) normal care and brief written information. Outcome measures at 12 months included the 7-day physical activity recall, the hospital anxiety and depression scale.ResultsOrdinal regression identified increased physical activity among those randomised to NERS compared with those receiving normal care in all participants (OR 1.19, 95% CI 0.99 to 1.43), and among those referred for CHD only (OR 1.29, 95% CI 1.04 to 1.60). For those referred for mental health reason alone, or in combination with CHD, there were significantly lower levels of anxiety (OR −1.56, 95% CI −2.75 to −0.38) and depression (OR −1.39, 95% CI −2.60 to −0.18), but no effect on physical activity. The base-case incremental cost-effectiveness ratio was £12 111 per quality adjusted life year, falling to £9741 if participants were to contribute £2 per session.ConclusionsNERS was effective in increasing physical activity among those referred for CHD risk only. Among mental health referrals, NERS did not influence physical activity but was associated with reduced anxiety and depression. Effects were dependent on adherence. NERS is likely to be cost effective with respect to prevailing payer thresholds.Trial registrationCurrent Controlled TrialsISRCTN47680448.
Chemosensitization of Cancer Cells by KU-0060648, a Dual Inhibitor of DNA-PK and PI-3K
Authors: Munck Joanne M. , Batey Michael A. , Zhao Yan , Jenkins Helen , Richardson Caroline J. , Cano Celine , Tavecchio Michele , Barbeau Jody , Bardos Julia , Cornell Liam , Griffin Roger J. , Menear Keith , Slade Andrew , Thommes Pia , Martin Niall M.B. , Newell David R. , Smith Graeme C.M. , Curtin Nicola J. 
Published: May 2012

Abstract
DNA double-strand breaks (DSB) are the most cytotoxic lesions induced by topoisomerase II poisons. Nonhomologous end joining (NHEJ) is a major pathway for DSB repair and requires DNA-dependent protein kinase (DNA-PK) activity. DNA-PK catalytic subunit (DNA-PKcs) is structurally similar to PI-3K, which promotes cell survival and proliferation and is upregulated in many cancers. KU-0060648 is a dual inhibitor of DNA-PK and PI-3K in vitro. KU-0060648 was investigated in a panel of human breast and colon cancer cells. The compound inhibited cellular DNA-PK autophosphorylation with IC50 values of 0.019 μmol/L (MCF7 cells) and 0.17 μmol/L (SW620 cells), and PI-3K–mediated AKT phosphorylation with IC50 values of 0.039 μmol/L (MCF7 cells) and more than 10 μmol/L (SW620 cells). Five-day exposure to 1 μmol/L KU-0060648 inhibited cell proliferation by more than 95% in MCF7 cells but only by 55% in SW620 cells. In clonogenic survival assays, KU-0060648 increased the cytotoxicity of etoposide and doxorubicin across the panel of DNA-PKcs–proficient cells, but not in DNA-PKcs–deficient cells, thus confirming that enhanced cytotoxicity was due to DNA-PK inhibition. In mice bearing SW620 and MCF7 xenografts, concentrations of KU-0060648 that were sufficient for in vitro growth inhibition and chemosensitization were maintained within the tumor for at least 4 hours at nontoxic doses. KU-0060648 alone delayed the growth of MCF7 xenografts and increased etoposide-induced tumor growth delay in both in SW620 and MCF7 xenografts by up to 4.5-fold, without exacerbating etoposide toxicity to unacceptable levels. The proof-of-principle in vitro and in vivo chemosensitization with KU-0060648 justifies further evaluation of dual DNA-PK and PI-3K inhibitors. Mol Cancer Ther; 11(8); 1789–98. ©2012 AACR.
Growth Inhibition of Ovarian Tumor–Initiating Cells by Niclosamide
Authors: Yo Yi-Te , Lin Ya-Wen , Wang Yu-Chi , Balch Curt , Huang Rui-Lan , Chan Michael W.Y. , Sytwu Huey-Kang , Chen Chi-Kuan , Chang Cheng-Chang , Nephew Kenneth P. , Huang Tim , Yu Mu-Hsien , Lai Hung-Cheng 
Published: May 2012

Abstract
A recent hypothesis for cancer chemoresistance posits that cytotoxic survival of a subpopulation of tumor progenitors drives the propagation of recurrent disease, underscoring the need for new therapeutics that target such primitive cells. To discover such novel compounds active against drug-resistant ovarian cancer, we identified a subset of chemoresistant ovarian tumor cells fulfilling current definitions of cancer-initiating cells from cell lines and patient tumors using multiple stemness phenotypes, including the expression of stem cell markers, membrane dye efflux, sphere formation, potent tumorigenicity, and serial tumor propagation. We then subjected such stem-like ovarian tumor-initiating cells (OTIC) to high-throughput drug screening using more than 1,200 clinically approved drugs. Of 61 potential compounds preliminarily identified, more stringent assessments showed that the antihelmintic niclosamide selectively targets OTICs in vitro and in vivo. Gene expression arrays following OTIC treatment revealed niclosamide to disrupt multiple metabolic pathways affecting biogenetics, biogenesis, and redox regulation. These studies support niclosamide as a promising therapy for ovarian cancer and warrant further preclinical and clinical evaluation of this safe, clinically proven drug for the management of this devastating gynecologic malignancy. Mol Cancer Ther; 11(8); 1703–12. ©2012 AACR.
A Comparison Between Antihypertensive Medication Adherence and Treatment Intensification as Potential Clinical Performance Measures
Authors: Vigen Rebecca , Shetterly Susan , Magid David J. , O'Connor Patrick J. , Margolis Karen L. , Schmittdiel Julie , Ho P. Michael 
Published: May 2012

Background—
Medication adherence and treatment intensification have been advocated as performance measures to assess the quality of care provided. Whereas previous studies have shown that adherence and treatment intensification (TI) of antihypertensive medications is associated with blood pressure (BP) control at the patient level, less is known about whether adherence and TI is associated with BP control at the clinic level.

Methods and Results—
We included 162 879 patients among 89 clinics in the Cardiovascular Research Network Hypertension Registry with incident hypertension who were started on antihypertensive medications. Adherence was measured by the proportion of days covered (PDC). TI was defined by the standard based method with scores ranging between −1 to 1 and categorized as: −1 indicated no TI occurred when BP was elevated; 0 indicated TI occurred when BP was elevated; and 1 indicated that TI was made at all visits, even when BP was not elevated. Logistic regression models assessed the association between adherence and TI with blood pressure control (BP ≤140/90 at the clinic visit closest to 12 months after study entry) at the patient and clinic levels. Mean adherence was 0.77±0.28 (PDC±SD) at the patient level and 0.78±0.05 at the clinic level. Mean TI was 0.026±0.23 at the patient level and 0.01±0.04 at the clinic level. At the patient level, for each 0.25 increase in adherence and TI, the odds (OR) of achieving blood pressure control increased by 28% and 55%, respectively [OR for adherence, 1.28 (1.26–1.29), and for TI, 1.55 (1.53–1.57)]. At the clinic level, each 0.04 increment increase in treatment intensification was associated with a 25% increased odds of achieving blood pressure control (OR, 1.24; 95% CI, 1.21–1.27). In contrast, there was an inverse association between increasing adherence and BP control (OR, 0.93; 95% confidence interval, 0.90–0.95).

Conclusions—
Patient adherence to antihypertensive medications is not associated with BP control at the clinic level and may not be suitable as a performance measure. TI is associated with BP control, but its use as a performance measure may be constrained by challenges in measuring it and by concerns about unintended consequences of aggressive hypertension treatment in some subgroups of patients.
Hospital Percutaneous Coronary Intervention Appropriateness and In-Hospital Procedural Outcomes
Authors: Bradley Steven M. , Chan Paul S. , Spertus John A. , Kennedy Kevin F. , Douglas Pamela S. , Patel Manesh R. , Anderson H. Vernon , Ting Henry H. , Rumsfeld John S. , Nallamothu Brahmajee K. 
Published: May 2012

Background—
Measurement of hospital quality has traditionally focused on processes of care and postprocedure outcomes. Appropriateness measures for percutaneous coronary intervention (PCI) assess quality as it relates to patient selection and the decision to perform PCI. The association between patient selection for PCI and processes of care and postprocedural outcomes is unknown.

Methods and Results—

We included 203 531 patients undergoing nonacute (elective) PCI from 779 hospitals participating in the National Cardiovascular Data Registry (NCDR) CathPCI Registry between July 2009 and April 2011. We examined the association between a hospital's proportion of nonacute PCIs categorized as inappropriate by the 2009 Appropriate Use Criteria (AUC) for Coronary Revascularization and in-hospital mortality, bleeding complications, and use of optimal guideline-directed medical therapy at discharge (ie, aspirin, thienopyridines, and statins). When categorized as hospital tertiles, the range of inappropriate PCI was 0.0% to 8.1% in the lowest tertile, 8.1% to 15.2% in the middle tertile, and 15.2% to 58.6% in the highest tertile. Compared with lowest-tertile hospitals, mortality was not significantly different at middle-tertile (adjusted odds ratio [OR], 0.93; 95% confidence interval [CI], 0.73–1.19) or highest-tertile hospitals (OR, 1.12; 95% CI, 0.88–1.43;
P
=0.35 for differences between tertiles). Similarly, risk-adjusted bleeding did not vary significantly (middle-tertile OR, 1.13; 95% CI, 1.02–1.16; highest-tertile OR, 1.02; 95% CI, 0.91–1.16;
P
=0.07 for differences between tertiles) nor did use of optimal medical therapy at discharge (85.3% versus 85.7% versus 85.2%;
P
=0.58).

Conclusions—
In a national cohort of nonacute PCIs, a hospital's proportion of inappropriate PCIs was not associated with in-hospital mortality, bleeding, or medical therapy at discharge. This suggests PCI appropriateness measures aspects of hospital PCI quality that are independent of how well the procedure is performed. Therefore, PCI appropriateness and postprocedural outcomes are both important metrics to inform PCI quality.
Procedure Intensity and the Cost of Care
Authors: Chen Serene I. , Dharmarajan Kumar , Kim Nancy , Strait Kelly M. , Li Shu-Xia , Safavi Kyan C. , Lindenauer Peter K. , Krumholz Harlan M. , Lagu Tara 
Published: May 2012

Background—
The intensive practice style of hospitals with high procedure rates may result in higher costs of care for medically managed patients. We sought to determine how costs for patients with heart failure (HF) not receiving procedures compare between hospital groups defined by their overall use of procedures.

Methods and Results—

We identified all 2009 to 2010 adult HF hospitalizations in hospitals capable of performing invasive procedures that had at least 25 HF hospitalizations in the Perspective database from Premier, Inc. We divided hospitals into 2 groups by the proportion of patients with HF receiving invasive percutaneous or surgical procedures: low (>0%–10%) and high (≥10%). The standard costs of hospitalizations at each hospital were risk adjusted using patient demographics and comorbidities. We used the Wilcoxon rank sum test to assess cost, length of stay, and mortality outcome differences between the 2 groups. Median risk-standardized costs among low-procedural HF hospitalizations were $5259 (interquartile range, $4683–$6814) versus $6965 (interquartile range, $5981–$8235) for hospitals with high procedure use (
P
<0.001). Median length of stay was 4 days for both groups. Risk-standardized mortality rates were 5.4% (low procedure) and 5.0% (high procedure) (
P
=0.009). We did not identify any single service area that explained the difference in costs between hospital groups, but these hospitals had higher costs for most service areas.

Conclusion—
Among patients who do not receive invasive procedures, the cost of HF hospitalization is higher in more procedure-intense hospitals compared with hospitals that perform fewer procedures.
Outcomes for Mitral Valve Surgery Among Medicare Fee-for-Service Beneficiaries, 1999 to 2008
Authors: Dodson John A. , Wang Yun , Desai Mayur M. , Barreto-Filho Jose Augusto , Sugeng Lissa , Hashim Sabet W. , Krumholz Harlan M. 
Published: May 2012

Background—
Mitral valve surgery in older adults carries with it substantial morbidity and mortality risks, yet there are a paucity of national surveillance data. Therefore, we sought to determine trends in hospitalization rate, readmission, and mortality among Medicare fee-for-service (FFS) patients undergoing mitral valve surgery.

Methods and Results—

Inpatient Medicare standard analytic files were used to identify 100% of FFS patients aged ≥65 years who underwent mitral valve surgery between 1999 and 2008. We constructed a denominator file from Medicare administrative data to report hospitalization rates for mitral valve surgery (total and isolated) per 100 000 beneficiary-years. For isolated mitral valve surgery, 30-day readmission, 30-day mortality, and 1-year mortality outcomes were ascertained through corresponding inpatient and vital status files, and risk-standardized rates were calculated adjusting for age, sex, race, and comorbidities. During 1999 to 2008, the overall rate of mitral valve surgery per 100K beneficiary-years declined (56/100K to 51/100K), and the proportion of patients undergoing mitral valve repair (versus replacement) increased (24.7% to 46.9%,
P
<0.001). For isolated mitral valve surgery, there were significant declines in risk-adjusted 30-day mortality (8.1% to 4.2%,
P
<0.001 for trend) and 1-year mortality (15.3% to 9.2%,
P
=0.003 for trend) and a slight decline in risk-adjusted 30-day readmission (23.0% to 21.0%,
P
=0.035 for trend) over the study period. Mortality rates decreased in all age, sex, and race subgroups, and among patients undergoing mitral valve repair or replacement, but remained higher among patients aged ≥85 years, women, and nonwhites.

Conclusions—
Between 1999 and 2008, outcomes after isolated mitral valve surgery significantly improved among Medicare FFS patients. Disparities among demographic subgroups indicate potential areas for quality improvement.