bluuebunny/crossref_metadata_2025_split huggingface dataset:
Verification of dosimetric accuracy on the TrueBeam STx: Rounded leaf effect of the high definition MLC
Authors: Kielar Kayla N. , Mok Ed , Hsu Annie , Wang Lei , Luxton Gary 
Published: October 2012

Purpose:The dosimetric leaf gap (DLG) in the Varian Eclipse treatment planning system is determined during commissioning and is used to model the effect of the rounded leaf‐end of the multileaf collimator (MLC). This parameter attempts to model the physical difference between the radiation and light field and account for inherent leakage between leaf tips. With the increased use of single fraction high dose treatments requiring larger monitor units comes an enhanced concern in the accuracy of leakage calculations, as it accounts for much of the patient dose. This study serves to verify the dosimetric accuracy of the algorithm used to model the rounded leaf effect for the TrueBeam STx, and describes a methodology for determining best‐practice parameter values, given the novel capabilities of the linear accelerator such as flattening filter free (FFF) treatments and a high definition MLC (HDMLC).Methods:During commissioning, the nominal MLC position was verified and the DLG parameter was determined using MLC‐defined field sizes and moving gap tests, as is common in clinical testing. Treatment plans were created, and the DLG was optimized to achieve less than 1% difference between measured and calculated dose. The DLG value found was tested on treatment plans for all energies (6 MV, 10 MV, 15 MV, 6 MV FFF, 10 MV FFF) and modalities (3D conventional, IMRT, conformal arc, VMAT) available on the TrueBeam STx.Results:The DLG parameter found during the initial MLC testing did not match the leaf gap modeling parameter that provided the most accurate dose delivery in clinical treatment plans. Using the physical leaf gap size as the DLG for the HDMLC can lead to 5% differences in measured and calculated doses.Conclusions:Separate optimization of the DLG parameter using end‐to‐end tests must be performed to ensure dosimetric accuracy in the modeling of the rounded leaf ends for the Eclipse treatment planning system. The difference in leaf gap modeling versus physical leaf gap dimensions is more pronounced in the more recent versions of Eclipse for both the HDMLC and the Millennium MLC. Once properly commissioned and tested using a methodology based on treatment plan verification, Eclipse is able to accurately model radiation dose delivered for SBRT treatments using the TrueBeam STx.
Multiresolution MR elastography using nonlinear inversion
Authors: McGarry M. D. J. , Van Houten E. E. W. , Johnson C. L. , Georgiadis J. G. , Sutton B. P. , Weaver J. B. , Paulsen K. D. 
Published: October 2012

Purpose:Nonlinear inversion (NLI) in MR elastography requires discretization of the displacement field for a finite element (FE) solution of the “forward problem”, and discretization of the unknown mechanical property field for the iterative solution of the “inverse problem”. The resolution requirements for these two discretizations are different: the forward problem requires sufficient resolution of the displacement FE mesh to ensure convergence, whereas lowering the mechanical property resolution in the inverse problem stabilizes the mechanical property estimates in the presence of measurement noise. Previous NLI implementations use the same FE mesh to support the displacement and property fields, requiring a trade‐off between the competing resolution requirements.Methods:This work implements and evaluates multiresolution FE meshes for NLI elastography, allowing independent discretizations of the displacements and each mechanical property parameter to be estimated. The displacement resolution can then be selected to ensure mesh convergence, and the resolution of the property meshes can be independently manipulated to control the stability of the inversion.Results:Phantom experiments indicate that eight nodes per wavelength (NPW) are sufficient for accurate mechanical property recovery, whereas mechanical property estimation from 50 Hzin vivo brain data stabilizes once the displacement resolution reaches 1.7 mm (approximately 19 NPW). Viscoelastic mechanical property estimates of in vivo brain tissue show that subsampling the loss modulus while holding the storage modulus resolution constant does not substantially alter the storage modulus images. Controlling the ratio of the number of measurements to unknown mechanical properties by subsampling the mechanical property distributions (relative to the data resolution) improves the repeatability of the property estimates, at a cost of modestly decreased spatial resolution.Conclusions:Multiresolution NLI elastography provides a more flexible framework for mechanical property estimation compared to previous single mesh implementations.
Intragenic Suppressor of a Plug Deletion Nonmotility Mutation in PotB, a Chimeric Stator Protein of Sodium-Driven Flagella
Authors: Zhu Shiwei , Homma Michio , Kojima Seiji 
Published: October 2012

ABSTRACT

The torque of bacterial flagellar motors is generated by interactions between the rotor and the stator and is coupled to the influx of H
+
or Na
+
through the stator. A chimeric protein, PotB, in which the N-terminal region of
Vibrio alginolyticus
PomB was fused to the C-terminal region of
Escherichia coli
MotB, can function with PomA as a Na
+
-driven stator in
E. coli
. Here, we constructed a deletion variant of PotB (with a deletion of residues 41 to 91 [Δ41–91], called PotBΔL), which lacks the periplasmic linker region including the segment that works as a “plug” to inhibit premature ion influx. This variant did not confer motile ability, but we isolated a Na
+
-driven, spontaneous suppressor mutant, which has a point mutation (R109P) in the MotB/PomB-specific α-helix that connects the transmembrane and peptidoglycan binding domains of PotBΔL in the region of MotB. Overproduction of the PomA/PotBΔL(R109P) stator inhibited the growth of
E. coli
cells, suggesting that this stator has high Na
+
-conducting activity. Mutational analyses of Arg109 and nearby residues suggest that the structural alteration in this α-helix optimizes PotBΔL conformation and restores the proper arrangement of transmembrane helices to form a functional channel pore. We speculate that this α-helix plays a key role in assembly-coupled stator activation.
Two Transporters Essential for Reassimilation of Novel Cholate Metabolites by Rhodococcus jostii RHA1
Authors: Swain Kendra , Casabon Israël , Eltis Lindsay D. , Mohn William W. 
Published: October 2012

ABSTRACT

The bacterial uptake of steroids and their metabolites remains poorly understood. We investigated two transporters associated with cholate catabolism in
Rhodococcus jostii
RHA1. Reverse transcriptase quantitative-PCR indicated that an ATP-binding cassette (ABC) transporter and a major facilitator superfamily (MFS) transporter were upregulated 16.7- and 174-fold, respectively, during the exponential phase of growth on cholate compared to growth on pyruvate. Gene knockout analysis established that these transporters are required for the reassimilation of distinct metabolites that accumulate during growth on cholate. The ABC transporter, encoded by
camABCD
, was essential for uptake of 1β(2′-propanoate)-3aα-
H
-4α(3″
(R)
-hydroxy-3″-propanoate)-7aβ-methylhexahydro-5-indanone and a desaturated analog. The MFS transporter, encoded by
camM
, was essential for uptake of 3,7
(R)
,12
(S)
-trihydroxy-9-oxo-9,10-seco-23,24-bisnorchola-1,3,5(10)-trien-22-oate. These metabolites differ from cholate metabolites reported to be excreted by proteobacteria in that they retain an isopropanoyl side chain at C-17. The uptake of these metabolites was necessary for maximal growth on cholate: a Δ
camB
mutant lacking the permease component of the ABC transporter and a Δ
camM
mutant lacking the MFS transporter grew to 74% and 77%, respectively, of the yield of the wild type. This study demonstrates for the first time the requirement for specific transporters for uptake of cholate metabolites and highlights the importance and complexity of transport processes associated with bacterial steroid catabolism.
Gene Cluster Encoding Cholate Catabolism in Rhodococcus spp
Authors: Mohn William W. , Wilbrink Maarten H. , Casabon Israël , Stewart Gordon R. , Liu Jie , van der Geize Robert , Eltis Lindsay D. 
Published: October 2012

ABSTRACT

Bile acids are highly abundant steroids with important functions in vertebrate digestion. Their catabolism by bacteria is an important component of the carbon cycle, contributes to gut ecology, and has potential commercial applications. We found that
Rhodococcus jostii
RHA1 grows well on cholate, as well as on its conjugates, taurocholate and glycocholate. The transcriptome of RHA1 growing on cholate revealed 39 genes upregulated on cholate, occurring in a single gene cluster. Reverse transcriptase quantitative PCR confirmed that selected genes in the cluster were upregulated 10-fold on cholate versus on cholesterol. One of these genes,
kshA3
, encoding a putative 3-ketosteroid-9α-hydroxylase, was deleted and found essential for growth on cholate. Two coenzyme A (CoA) synthetases encoded in the cluster, CasG and CasI, were heterologously expressed. CasG was shown to transform cholate to cholyl-CoA, thus initiating side chain degradation. CasI was shown to form CoA derivatives of steroids with isopropanoyl side chains, likely occurring as degradation intermediates. Orthologous gene clusters were identified in all available
Rhodococcus
genomes, as well as that of
Thermomonospora curvata
. Moreover,
Rhodococcus equi
103S,
Rhodococcus ruber
Chol-4 and
Rhodococcus erythropolis
SQ1 each grew on cholate. In contrast, several mycolic acid bacteria lacking the gene cluster were unable to grow on cholate. Our results demonstrate that the above-mentioned gene cluster encodes cholate catabolism and is distinct from a more widely occurring gene cluster encoding cholesterol catabolism.
Anticipatory prescribing in terminal care at home: what challenges do community health professionals encounter?
Authors: Faull Christina , Windridge Kate , Ockleford Elizabeth , Hudson Michael 
Published: October 2012

BackgroundThe prompt availability of medications to manage symptoms is key to high quality end-of-life care and anticipatory prescribing of these drugs is thought good practice. This study explored the challenges encountered by primary and community health professionals in Leicestershire and Rutland related to anticipatory prescribing when caring for terminally ill patients who wish to remain at home to die.MethodA qualitative study was conducted using eight focus groups (54 participants) and nine individual interviews with a purposively sampled range of health professionals providing care for people who wished to die at home. Themes were identified iteratively via constant comparison.ResultsChallenges fell into four categories: resourcing concerns, professional expertise/experience, professionals’ relationships with patients, and professionals’ relationships with other professionals. The latter included the most serious perceived challenges. Links between community and hospital care providers and between ‘usual’ hours and ‘out-of-hours’ care providers were seen as particularly unstable.ConclusionsThese findings suggest that building and maintaining trusting, responsive, personal links between professionals, both within and between teams, is essential when implementing good practice guidelines about anticipatory end-of-life prescribing in the community. The need for good communication and relationships between patients and professionals and maintaining expertise and confidence in end-of-life care are also key factors in the effective use of anticipatory prescribing for symptom management for dying patients.
Self-collected swabs of the urinary meatus diagnose moreChlamydia trachomatisandNeisseria gonorrhoeaeinfections than first catch urine from men
Authors: Chernesky Max A , Jang Dan , Portillo Eder , Smieja Marek , Gilchrist Jodi , Ewert Ruth , MacRitchie Cindy 
Published: October 2012

ObjectivesTo compare first catch urine (FCU) and self-collected urinary meatal swabs for the detection ofChlamydia trachomatis(CT) andNeisseria gonorrhoeae(NG) using the APTIMA Combo 2 assay.MethodsA total of 511 young men from a high risk street youth clinic were studied. Group A (n=293) collected a FCU and a meatal APTIMA swab followed by Group B (n=218) who collected a FCU and two meatal samples using an APTIMA swab and a flocked swab. Order of sample collection was alternated. Individuals in Group B rated collection as easy, difficult or neither, then expressed a preference for sampling and swab type. All subjects performed meatal self-collection in the presence of a study monitor.ResultsThe combined CT prevalence was 7.8% and 2.7% for NG where 80% of the men were without symptoms. Meatal swabbing identified 35 cases of CT and 14 cases of NG compared to 33 and 11 for FCU. Flocked and APTIMA swabs were equally effective in detecting more cases. The majority of men found self-collection of meatal swabs and urine to be easy. Although 63% preferred urine sampling, 60% of those who preferred swabbing selected the flocked swab.ConclusionsCollection of meatal swabs could serve as an alternative to urethral swabbing and FCU for the detection of CT and NG.
Ten-Year Follow-up of a Prospective, Randomized Clinical Study of Mosaic Osteochondral Autologous Transplantation Versus Microfracture for the Treatment of Osteochondral Defects in the Knee Joint of Athletes
Authors: Gudas Rimtautas , Gudaitė Agnė , Pocius Arnoldas , Gudienė Asta , Čekanauskas Emilis , Monastyreckienė Eglė , Basevičius Algidas 
Published: October 2012

Background: Various techniques have proven to be effective for treating articular cartilage defect (ACD) and osteochondral defect (OCD) of the knee joint, but knowledge regarding which method is best still remains uncertain. Purpose: To evaluate and compare the outcomes of mosaic-type osteochondral autologous transplantation (OAT) and microfracture (MF) procedures for the treatment of articular cartilage defects of the knee joint in young active athletes. This article represents an update of the clinical results at 10 years. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: Between 1998 and 2002, a total of 60 athletes with a mean age of 24.3 years (range, 15-40 years) and with a symptomatic ACD or OCD in the knee were randomized to undergo either OAT or MF. Patients were then evaluated postoperatively using the International Cartilage Repair Society (ICRS) score, Tegner activity score, radiographs, and magnetic resonance imaging. The mean follow-up time was 10.4 years (range, 9-11 years). Results: Three to 10 years after the OAT and MF procedures, patients had lower ICRS and Tegner scores ( P < .05), but both groups still had significant clinical improvement over presurgery scores according to ICRS scores at 10-year follow-up. Statistically significantly better results were detected in patients in the OAT group compared with those in the MF group at 10 years ( P < .005). At 10-year follow-up, there were 15 failures (26%), including 4 failures (14%) of the OAT and 11 failures (38%) of MF treatment ( P < .05). Seven patients (25%) from the OAT group and 14 patients (48%) from the MF group had radiographic evidence of Kellgren-Lawrence grade I osteoarthritis at 10 years, but these differences were not significant ( P = .083) or related to the clinical results. The ICRS and Tegner scores of younger athletes (<25 years at the time of primary surgery) remained significantly higher after 10 years compared with older patients ( P < .05); 15 of 20 patients (75%) in the OAT group and 8 of 22 patients (37%) in the MF group maintained the same physical activity level. Conclusion: The OAT technique for ACD or OCD repair in the athletic population allows for a higher rate of return to and maintenance of sports at the preinjury level compared with MF.
Do the Traditional and Modified Latarjet Techniques Produce Equivalent Reconstruction Stability and Strength?
Authors: Giles Joshua W. , Puskas Gabor , Welsh Mark , Johnson James A. , Athwal George S. 
Published: October 2012

Background: The Latarjet procedure has been described as a reconstructive option for instability associated with substantial glenoid bone defects. A modification, termed the Congruent-Arc, is thought to improve glenoid reconstruction through better articular congruency and greater bone reconstitution. The strengths of these techniques, however, have not been reported. Purpose/Hypothesis: To compare the fixation stability, strength, glenoid vault load transfer, and joint contact between the Classic and Congruent-Arc techniques. The authors hypothesized that the Classic Latarjet would exhibit inferior joint contact characteristics while having greater stability and strength and more normal glenoid vault strain. Study Design: Controlled laboratory study. Methods: Sixteen shoulder specimens (8 pairs) were tested by loading the glenohumeral joint with the glenoid intact, following creation of a 25% anterior bone defect, and after random assignment to the Classic or Congruent-Arc Latarjet techniques. Specimens were mounted to a testing apparatus that allowed concentric, centralized loading and loading 30° anterior on the glenoid rim. Cyclic loading (100 cycles at 1 Hz) was applied with a staircase protocol (50, 100, 150, and 200 N). Graft interface displacement and glenoid load transfer, quantified in terms of strain, were recorded during loading. Contact was quantified during 50-N loading using a thin pressure sensor. After cyclic loading, specimens were loaded to failure, defined as 5 mm of graft interface displacement. Results: The 30° loading ≥100 N resulted in significantly greater graft displacement ( P < .004) in the Congruent-Arc group as compared with the Classic (mean displacement range, 0.9-2.6 vs 0.1-0.5 mm, respectively). Failure testing yielded a significantly ( P = .010) greater ultimate strength for the Classic (557 N) as compared with the Congruent-Arc (392 N). Load-transfer measurements demonstrated that neither technique’s glenoid vault strain values significantly differed from intact ( P ≥ .076). Both techniques resulted in contact areas significantly less than intact ( P < .035); however, the Congruent-Arc trended toward better contact characteristics ( P = .074). Conclusion: The Congruent-Arc results in significantly poorer fixation stability as compared with the Classic technique but did more closely reproduce intact joint contact, which may yield more favorable long-term outcomes. Clinical Relevance: Care must be taken in balancing the consideration of initial fixation stability and joint contact for the Congruent-Arc and Classic Latarjet, as these factors have opposing implications for each of the 2 reconstructions’ outcomes.
Anomalous aortic origin of coronary arteries from the opposite sinus: A critical appraisal of risk
Authors: Peñalver Josiah M , Mosca Ralph S , Weitz Daniel , Phoon Colin KL 
Published: October 2012

Abstract

Background
Anomalous aortic origin of the coronary artery (AAOCA) from the opposite sinus of Valsalva with an interarterial course has received much attention due to its association with sudden death in otherwise healthy individuals. AAOCA is relatively common and may have significant public health implications. While our knowledge of its pathophysiology and natural history remains incomplete, an emphasis has been placed on surgical correction.

Discussion
In 2005 we published a review examining the rates of sudden death with AAOCA, as well as complications of surgical management. Evidence now points even more strongly to lower rates of sudden death, while surgical outcomes data now better documents associated risks.

Summary
Armed with this updated information, we agree with the need for a national registry to better track patients with AAOCA. We submit that the risks of surgical management outweigh any benefits in the asymptomatic patient with anomalous right coronary artery, and expectant management should also be strongly considered even in asymptomatic patients with anomalous left coronary artery.
CHD1L Protein is overexpressed in human ovarian carcinomas and is a novel predictive biomarker for patients survival
Authors: He Wei-Peng , Zhou Juan , Cai Mu-Yan , Xiao Xiang-Shen , Liao Yi-Ji , Kung Hsiang-Fu , Guan Xin-Yuan , Xie Dan , Yang Guo-Fen 
Published: October 2012

Abstract

Background
Our recent studies suggested that the chromodomain helicase DNA binding protein 1-like (CHD1L) gene plays an oncogenic role in human hepatocellular carcinoma. However, the status of CHD1L protein expression in ovarian cancer and its clinical/prognostic significance are obscure.

Methods
In this study, immunohistochemistry (IHC) for CHD1L was performed on a tissue microarray (TMA) containing 102 primary ovarian carcinomas and 44 metastatic lesions (omental metastasis). Receiver-operator curve (ROC) analysis was used to evaluate patients’ survival status.

Results
There is an augmented tendency of CHD1L expression in ovarian carcinoma metastasis than in primary lesions (P<0.05). A significant association was found between positive expression of CHD1L and tumors histological type (P <0.05). By univariate survival analysis of the ovarian carcinoma cohorts, positive expression of CHD1L was significantly correlated with shortened patient survival (mean 66.7 months versus 97.4 months, P<0.05). Moreover, CHD1L expression was evaluated to be a significant and independent prognostic factor in multivariate analysis (P<0.05).

Conclusions
These findings provide evidence that positive expression of CHD1L protein is significantly correlated with the metastasis proceeding of ovarian carcinoma, and CHD1L protein expression, as examined by IHC, may act as a novel prognostic biomarker for patients with ovarian carcinoma.
Influenza epidemics, seasonality, and the effects of cold weather on cardiac mortality
Authors: von Klot Stephanie , Zanobetti Antonella , Schwartz Joel 
Published: October 2012

Abstract

Background
More people die in the winter from cardiac disease, and there are competing hypotheses to explain this. The authors conducted a study in 48 US cities to determine how much of the seasonal pattern in cardiac deaths could be explained by influenza epidemics, whether that allowed a more parsimonious control for season than traditional spline models, and whether such control changed the short term association with temperature.

Methods
The authors obtained counts of daily cardiac deaths and of emergency hospital admissions of the elderly for influenza during 1992–2000. Quasi-Poisson regression models were conducted estimating the association between daily cardiac mortality, and temperature.

Results
Controlling for influenza admissions provided a more parsimonious model with better Generalized Cross-Validation, lower residual serial correlation, and better captured Winter peaks. The temperature-response function was not greatly affected by adjusting for influenza. The pooled estimated increase in risk for a temperature decrease from 0 to −5°C was 1.6% (95% confidence interval (CI) 1.1-2.1%). Influenza accounted for 2.3% of cardiac deaths over this period.

Conclusions
The results suggest that including epidemic data explained most of the irregular seasonal pattern (about 18% of the total seasonal variation), allowing more parsimonious models than when adjusting for seasonality only with smooth functions of time. The effect of cold temperature is not confounded by epidemics.