bluuebunny/crossref_metadata_2025_split huggingface dataset:
Self‐regulation following prostatectomy: Phase‐specific self‐efficacy beliefs for pelvic‐floor exercise
Authors: Burkert S , Knoll N , Scholz U , Roigas J , Gralla O 
Published: June 2011

Objective. Beliefs in one's ability to perform a task or behaviour successfully are described as self‐efficacy beliefs (Bandura, 1977). Since individuals have to deal with differing demands during a behaviour‐change process, they form phase‐specific self‐efficacy beliefs directed at these respective challenges. The present study, based on the Health Action Process Approach (Schwarzer, 2001), examines the theoretical differentiation, relative importance, and differential effects of four phase‐specific self‐efficacy beliefs, including task self‐efficacy, preactional self‐efficacy, maintenance self‐efficacy, and recovery self‐efficacy.Design. In a prospective longitudinal study, 112 prostatectomy‐patients received questionnaires at 2 days, 2 weeks, 1 month, and 6 months post‐surgery.Methods. Participants provided data on phase‐specific self‐efficacies as well as phase indicators of health‐behaviour change, that is, intentions, planning, and pelvic‐floor exercise. Hierarchical regression analyses were conducted to test the study hypotheses.Results. Task self‐efficacy was not uniquely associated with intentions. Preactional self‐efficacy was related to action planning. Maintenance self‐efficacy did not predict behaviour. Recovery self‐efficacy was associated with re‐uptake of pelvic‐floor exercise after relapses only.Conclusion. Findings underline the importance of differentiating between task self‐efficacy and preactional self‐efficacy during early phases of behaviour change as well as of considering the occurrence of relapses as a moderator of potential effects of recovery self‐efficacy on the maintenance of behaviour change. Advanced knowledge on distinct, phase‐specific self‐efficacy beliefs may facilitate the design of effective tailored interventions for behaviour change.
Data-Driven Design Optimization for Composite Material Characterization
Authors: Michopoulos John G. , Hermanson John C. , Iliopoulos Athanasios , Lambrakos Samuel G. , Furukawa Tomonari 
Published: June 2011

Abstract
The main goal of the present paper is to demonstrate the value of design optimization beyond its use for structural shape determination in the realm of the constitutive characterization of anisotropic material systems such as polymer matrix composites with or without damage. The approaches discussed are based on the availability of massive experimental data representing the excitation and response behavior of specimens tested by automated mechatronic material testing systems capable of applying multiaxial loading. Material constitutive characterization is achieved by minimizing the difference between experimentally measured and analytically computed system responses as described by surface strain and strain energy density fields. Small and large strain formulations based on additive strain energy density decompositions are introduced and utilized for constructing the necessary objective functions and their subsequent minimization. Numerical examples based on both synthetic (for one-dimensional systems) and actual data (for realistic 3D material systems) demonstrate the successful application of design optimization for constitutive characterization.
Correlation and prediction uncertainties in the CyberKnife Synchrony respiratory tracking system
Authors: Pepin Eric W. , Wu Huanmei , Zhang Yuenian , Lord Bryce 
Published: June 2011

Purpose:The CyberKnife uses an online prediction model to improve radiation delivery when treating lung tumors. This study evaluates the prediction model used by the CyberKnife radiation therapy system in terms of treatment margins about the gross tumor volume (GTV).Methods:From the data log files produced by the CyberKnife synchrony model, the uncertainty in radiation delivery can be calculated. Modeler points indicate the tracked position of the tumor and Predictor points predict the position about 115 ms in the future. The discrepancy between Predictor points and their corresponding Modeler points was analyzed for 100 treatment model data sets from 23 de‐identified lung patients. The treatment margins were determined in each anatomic direction to cover an arbitrary volume of the GTV, derived from the Modeler points, when the radiation is targeted at the Predictor points. Each treatment model had about 30 min of motion data, of which about 10 min constituted treatment time; only these 10 min were used in the analysis. The frequencies of margin sizes were analyzed and truncated Gaussian normal functions were fit to each direction's distribution. The standard deviation of each Gaussian distribution was then used to describe the necessary margin expansions in each signed dimension in order to achieve the desired coverage. In this study, 95% modeler point coverage was compared to 99% modeler coverage. Two other error sources were investigated: the correlation error and the targeting error. These were added to the prediction error to give an aggregate error for the CyberKnife during treatment of lung tumors.Results:Considering the magnitude of 2σ from the mean of the Gaussian in each signed dimension, the margin expansions needed for 95% modeler point coverage were 1.2 mm in the lateral (LAT) direction and 1.7 mm in the anterior–posterior (AP) direction. For the superior–inferior (SI) direction, the fit was poor; but empirically, the expansions were 3.5 mm. For 99% modeler point coverage, the AP margin was 3.6 mm and the lateral margin was 2.9 mm. The SI margins for 99% modeler point coverage were highly variable. The aggregate error at 95% was 6.9 mm in the SI direction, 4.6 mm in the AP direction, and 3.5 in the lateral direction.Conclusions:The Predictor points follow the Modeler points closely. Margins were found in each clinical direction that would provide 95% modeler point coverage for 95% of the models reviewed in this study. Similar margins were found in two clinical directions for 99% modeler point coverage in 95% of models. These results can offer guidance in the selection of CTV margins for treatment with the CyberKnife.
High dose per fraction dosimetry of small fields with Gafchromic EBT2 film
Authors: Hardcastle Nicholas , Basavatia Amar , Bayliss Adam , Tomé Wolfgang A. 
Published: June 2011

Purpose:Small field dosimetry is prone to uncertainties due to the lack of electronic equilibrium and the use of the correct detector size relative to the field size measured. It also exhibits higher sensitivity to setup errors as well as large variation in output with field size and shape. Radiochromic film is an attractive method for reference dosimetry in small fields due to its ability to provide 2D dose measurements while having minimal impact on the dose distribution. Gafchromic EBT2 has a dose range of up to 40 Gy; therefore, it could potentially be useful for high dose reference dosimetry with high spatial resolution. This is a requirement in stereotactic radiosurgery deliveries, which deliver high doses per fraction to small targets.Methods:Targets of 4 mm and 12 mm diameters were treated to a minimum peripheral dose of 21 Gy prescribed to 80% of the maximum dose in one fraction. Target doses were measured with EBT2 film (both targets) and an ion chamber (12 mm target only). Measured doses were compared with planned dose distributions using profiles through the target and minimum peripheral dose coverage.Results:The measured target doses and isodose coverage agreed with the planned dose within ±1 standard deviation of three measurements, which were 2.13% and 2.5% for the 4 mm and 12 mm targets, respectively.Conclusions:EBT2 film is a feasible dosimeter for high dose per fraction reference 2D dosimetry.
IPIP: A new approach to inverse planning for HDR brachytherapy by directly optimizing dosimetric indices
Authors: Siauw Timmy , Cunha Adam , Atamtürk Alper , Hsu I‐Chow , Pouliot Jean , Goldberg Ken 
Published: June 2011

Purpose:Many planning methods for high dose rate (HDR) brachytherapy require an iterative approach. A set of computational parameters are hypothesized that will give a dose plan that meets dosimetric criteria. A dose plan is computed using these parameters, and if any dosimetric criteria are not met, the process is iterated until a suitable dose plan is found. In this way, the dose distribution is controlled by abstract parameters. The purpose of this study is to develop a new approach for HDR brachytherapy by directly optimizing the dose distribution based on dosimetric criteria.Methods:The authors developed inverse planning by integer program (IPIP), an optimization model for computing HDR brachytherapy dose plans and a fast heuristic for it. They used their heuristic to compute dose plans for 20 anonymized prostate cancer image data sets from patients previously treated at their clinic database. Dosimetry was evaluated and compared to dosimetric criteria.Results:Dose plans computed from IPIP satisfied all given dosimetric criteria for the target and healthy tissue after a single iteration. The average target coverage was 95%. The average computation time for IPIP was 30.1 s on an Intel(R) CoreTM2 Duo CPU 1.67 GHz processor with 3 Gib RAM.Conclusions:IPIP is an HDR brachytherapy planning system that directly incorporates dosimetric criteria. The authors have demonstrated that IPIP has clinically acceptable performance for the prostate cases and dosimetric criteria used in this study, in both dosimetry and runtime. Further study is required to determine if IPIP performs well for a more general group of patients and dosimetric criteria, including other cancer sites such as GYN.
Inverse determination of the penalty parameter in penalized weighted least‐squares algorithm for noise reduction of low‐dose CBCT
Authors: Wang Jing , Guan Huaiqun , Solberg Timothy 
Published: June 2011

Purpose:A statistical projection restoration algorithm based on the penalized weighted least‐squares (PWLS) criterion can substantially improve the image quality of low‐dose CBCT images. The performance of PWLS is largely dependent on the choice of the penalty parameter. Previously, the penalty parameter was chosen empirically by trial and error. In this work, the authors developed an inverse technique to calculate the penalty parameter in PWLS for noise suppression of low‐dose CBCT in image guided radiotherapy (IGRT).Methods:In IGRT, a daily CBCT is acquired for the same patient during a treatment course. In this work, the authors acquired the CBCT with a high‐mAs protocol for the first session and then a lower mAs protocol for the subsequent sessions. The high‐mAs projections served as the goal (ideal) toward, which the low‐mAs projections were to be smoothed by minimizing the PWLS objective function. The penalty parameter was determined through an inverse calculation of the derivative of the objective function incorporating both the high and low‐mAs projections. Then the parameter obtained can be used for PWLS to smooth the noise in low‐dose projections. CBCT projections for a CatPhan® 600 and an anthropomorphic head phantom, as well as for a brain patient, were used to evaluate the performance of the proposed technique.Results:The penalty parameter in PWLS was obtained for each CBCT projection using the proposed strategy. The noise in the low‐dose CBCT images reconstructed from the smoothed projections was greatly suppressed. Image quality in PWLS‐processed low‐dose CBCT was comparable to its corresponding high‐dose CBCT.Conclusions:A technique was proposed to estimate the penalty parameter for PWLS algorithm. It provides an objective and efficient way to obtain the penalty parameter for image restoration algorithms that require predefined smoothing parameters.
New Channelrhodopsin with a Red-Shifted Spectrum and Rapid Kinetics from
Mesostigma viride
Authors: Govorunova Elena G. , Spudich Elena N. , Lane C. Elizabeth , Sineshchekov Oleg A. , Spudich John L. 
Published: June 2011

ABSTRACT

Light control of motility behavior (phototaxis and photophobic responses) in green flagellate algae is mediated by sensory rhodopsins homologous to phototaxis receptors and light-driven ion transporters in prokaryotic organisms. In the phototaxis process, excitation of the algal sensory rhodopsins leads to generation of transmembrane photoreceptor currents. When expressed in animal cells, the algal phototaxis receptors function as light-gated cation channels, which has earned them the name “channelrhodopsins.” Channelrhodopsins have become useful molecular tools for light control of cellular activity. Only four channelrhodopsins, identified in
Chlamydomonas reinhardtii
and
Volvox carteri
, have been reported so far. By screening light-induced currents among algal species, we identified that the phylogenetically distant flagellate
Mesostigma viride
showed photoelectrical responses
in vivo
with properties suggesting a channelrhodopsin especially promising for optogenetic use. We cloned an
M. viride
channelrhodopsin, MChR1, and studied its channel activity upon heterologous expression. Action spectra in HEK293 cells match those of the photocurrents observed in
M. viride
cells. Comparison of the more divergent MChR1 sequence to the previously studied phylogenetically clustered homologs and study of several MChR1 mutants refine our understanding of the sequence determinants of channelrhodopsin function. We found that MChR1 has the most red-shifted and pH-independent spectral sensitivity so far reported, matches or surpasses known channelrhodopsins’ channel kinetics features, and undergoes minimal inactivation upon sustained illumination. This combination of properties makes MChR1 a promising candidate for optogenetic applications.

IMPORTANCE
Channelrhodopsins that function as phototaxis receptors in flagellate algae have recently come into the spotlight as genetically encoded single-molecule optical switches for turning on neuronal firing or other cellular processes, a technique called “optogenetics.” Only one of four currently known channelrhodopsins is widely used in optogenetics, although electrical currents recorded in diverse flagellates suggest the existence of a large variety of such proteins. We applied a strategy for the search for new channelrhodopsins with desirable characteristics by measuring rhodopsin-mediated photocurrents in microalgae, which helped us identify MChR1, a new member of the channelrhodopsin family. MChR1 exhibits several sought-after characteristics and thus expands the available optogenetic toolbox. The divergence of the MChR1 sequence from those of the four known channelrhodopsins contributes to our understanding of diversity in the primary structures of this subfamily of sensory rhodopsins.
MMP-2 and MMP-9 in lymph-node-positive bladder cancer
Authors: Seiler Roland , Thalmann George N , Fleischmann Achim 
Published: June 2011

BackgroundMatrix metalloproteinases (MMP), particularly MMP-2 and MMP-9, participate in tumour progression and metastasis in various cancers. Their significance in urothelial cancer of the bladder (UCB) is unclear. Expression analysis of MMP-2 and MMP-9 in tissue microarrays (TMA) constructed of corresponding samples from histopathological normal urothelium, tumour centre and invasion front of primary tumours and lymph-node (LN) metastases might help to elucidate their relevance in UCB.MethodMMP-2 and MMP-9 expression was evaluated in TMA of 150 surgically treated LN-positive UCB patients. Biomarker expression was correlated with tumour characteristics (primary tumour and LN stage, number, total diameter and extracapsular extension of LN metastases) and overall survival.ResultsWhile there was a significant increase in MMP-9 expression from normal urothelium over primary tumours to metastases (median scores: 20, 50, 65; p<0.005), no such trend was observed in MMP-2 (median scores: 5, 22, 10; p<0.005). A comparison of expression in the tumour centre and the invasion front showed no difference in both MMP. No association between expression and histopathological tumour characteristics was identified. There was a non-significant trend for a more favourable outcome for patients with high MMP-2 expression in primary tumours.ConclusionIn LN-positive UCB, MMP-2 and MMP-9 expression was not increased at the invasion front, suggesting an infiltration strategy independent of MMP-2 and MMP-9 activity. Larger series are needed to detect a potential significant trend for favourable outcome in cancers with high MMP-2 expression.
Relationship between clock and star drawing and the degree of hepatic encephalopathy
Authors: Edwin Natasha , Peter John Victor , John George , Eapen C E , Graham Petra L 
Published: June 2011

ABSTRACT

Purpose of the study
Current hepatic encephalopathy grading tools are limited because of complexity or subjectivity. The degree of constructional apraxia could serve as a simple, objective and reproducible tool to grade encephalopathy.

Study design
In this cross-sectional study of patients with chronic liver disease, the degree of constructional apraxia was judged by their ability to copy a star and clock face and compared with conventional encephalopathy grading by the West Haven Criteria (WHC) and the Porto Systemic Encephalopathy Index (PSEI). Three blinded observers independently graded the figures. Sensitivity, specificity and positive predictive value (PPV) of clock and star scores (score 0 implying no encephalopathy and &gt;0 hepatic encephalopathy) were assessed against conventional scoring systems (WHC grade &gt;0 or PSEI ≥0.33 indicating encephalopathy). Mosaic and box plots were generated to assess if the degree of constructional apraxia correlated with the severity of encephalopathy.

Results
71 patients were studied between October 2008 and July 2009; 11 (15.4%) had WHC grade 0, 32 (45%) grade 1, and 28 (39.4%) grades 2 and 3 encephalopathy. The sensitivity, specificity and PPV of the clock drawing for the diagnosis of encephalopathy was 85%, 80%, and 96%, respectively, and 77%, 70%, and 94%, respectively, for the star drawing. Box plots and intervals on mean PSEI showed an increasing relationship between clock/star scores and PSEI. There was substantial agreement between WHC and clock (weighted κ 0.61) and star scores (weighted κ 0.71). Inter-observer reliability was at least 0.70 for star and at least 0.79 for the clock score.

Conclusion
Clock and star drawing may serve as reproducible, inexpensive bedside tools for diagnosing and grading the severity of hepatic encephalopathy.
How Dutch medical residents perceive their competency as manager in the revised postgraduate medical curriculum
Authors: Berkenbosch Lizanne , Brouns Judith W M , Heyligers Ide , Busari Jamiu O 
Published: June 2011

ABSTRACT

Introduction
In 2005, competency based training was introduced into the curriculum of the postgraduate training of Dutch medical residents. The role as manager is one of the seven competencies and, compared to the other roles, it is presently thought to receive little attention during training. The goal of this study was to investigate medical residents' understanding of this competency and how they perceive their role as manager.

Methods
In October 2009, 506 residents from different specialties in four teaching hospitals were invited via email to participate in the study. A 29-item Likert scale questionnaire was designed to investigate residents perceived healthcare management skills and knowledge in four management areas.

Results
177 of 506 residents (35%) responded to the survey. More than half of the residents (106/177, 60%) did not feel confident in their (contract) negotiating skills and 56% (98/175) stated that they lacked sufficient knowledge of how the Dutch healthcare system is financed and organised. The residents were most confident in their ability to handle feedback (151/177, 85%), medical information data registration (168/173, 97%), and how to allocate healthcare resources based on evidence based principles (143/173, 83%).

Conclusion
These results demonstrate that residents in the Netherlands perceive their knowledge and skills in certain essential medical management concepts to be inadequate. The results suggest that a course in medical management should be considered as a mandatory part of the curricula of residency training programmes.
General practice and social service partnership for better clinical outcomes, patient self efficacy and lifestyle behaviours of diabetic care: randomised control trial of a chronic care model
Authors: Lee Albert , Siu Choi-Fong , Leung Kam-Tao , Lau Louisa C H , Chan Cathy C M , Wong Kwok-Keung 
Published: June 2011

ABSTRACT

Background
The International Diabetes Attitudes, Wishes, and Needs (DAWN) programmes have shown the existence of a critical gap in self management support and access to the support system. This study aims to evaluate the effectiveness of the diabetes mellitus (DM) self management programme, with partnership between general practice and social work, on clinical outcomes, patient self efficacy and lifestyle behaviours.

Methods
In this is single blind randomised controlled trial, subjects were recruited from patients attending general outpatient clinics in the Hospital Authority New Territory East Cluster of Hong Kong. 157 subjects meeting the inclusion criteria completed the study and were randomly assigned to the experimental or control group. The experimental group underwent the six sessions of weekly DM self management course with emphasis on self efficacy and participatory approach. The outcome measurements included HbA1c concentration, DM self efficacy scale, dietary behaviours, body mass index (BMI), and waist: hip ratio.

Results
Baseline assessment observed no significant differences between experimental and control groups for the variables related to outcomes. For the experimental group, the proportion of subjects with normal HbA1c increased from 4.5% (3/66) at baseline to 28.6% (19/66) at week 28 (p&lt;0.001), but there was insignificant improvement in the control group (3.9% to 11.8%, p=0.13). Repeated measure of analysis of variance showed pronounced improvement in DM self efficacy scale and BMI among the experimental group with significant interaction. Dietary behaviours also improved significantly in the experimental group.

Conclusion
The DM care model with partnership between general practice and social work demonstrated better diabetic control with improvement of self efficacy and minimisation of risk behaviours.

Trial registration
Current Controlled Trials ISRCTN78882965.
Imatinib Sensitivity in BCR-ABL1–Positive Chronic Myeloid Leukemia Cells Is Regulated by the Remaining Normal ABL1 Allele
Authors: Virgili Anna , Koptyra Mateusz , Dasgupta Yashodhara , Glodkowska-Mrowka Eliza , Stoklosa Tomasz , Nacheva Elisabeth P. , Skorski Tomasz 
Published: June 2011

Abstract
Chronic myeloid leukemia in chronic phase (CML-CP) cells that harbor oncogenic BCR-ABL1 and normal ABL1 allele often become resistant to the ABL1 kinase inhibitor imatinib. Here, we report that loss of the remaining normal ABL1 allele in these tumors, which results from cryptic interstitial deletion in 9q34 in patients who did not achieve a complete cytogenetic remission (CCyR) during treatment, engenders a novel unexpected mechanism of imatinib resistance. BCR-ABL1–positive Abl1−/− leukemia cells were refractory to imatinib as indicated by persistent BCR-ABL1–mediated tyrosine phosphorylation, lack of BCR-ABL1 protein degradation, increased cell survival, and clonogenic activity. Expression of ABL1 kinase, but not a kinase-dead mutant, restored the antileukemic effects of imatinib in ABL1-negative chronic myelogenous leukemia (CML) cells and in BCR-ABL1–positive Abl1−/− murine leukemia cells. The intracellular concentration of imatinib and expression of its transporters were not affected, although proteins involved in BCR-ABL1 degradation were downregulated in Abl1−/− cells. Furthermore, 12 genes associated with imatinib resistance were favorably deregulated in Abl1−/− leukemia. Taken together, our results indicate that loss of the normal ABL1 kinase may serve as a key prognostic factor that exerts major impact on CML treatment outcomes. Cancer Res; 71(16); 5381–6. ©2011 AACR.