Axion-photon conversion at dielectric interfaces, immersed in a near-homogeneous magnetic field, is the basis for the dielectric haloscope method to search for axion dark matter. In analogy to ...transition radiation, this process is possible because the photon wave function is modified by the dielectric layers ('Garibian wave function') and is no longer an eigenstate of momentum. A conventional first-order perturbative calculation of the transition probability between a quantized axion state and these distorted photon states provides the microwave production rate. It agrees with previous results based on solving the classical Maxwell equations for the combined system of axions and electromagnetic fields. We argue that in general the average photon production rate is given by our result, independently of the detailed quantum state of the axion field. Moreover, our result provides a new perspective on axion-photon conversion in dielectric haloscopes because the rate is based on an overlap integral between unperturbed axion and photon wave functions, in analogy to the usual treatment of microwave-cavity haloscopes.
We recently introduced a screening technology termed ligand-guided selection, (LIGS), to selectively identify target-specific aptamers from an evolved cell-SELEX library. Cell-SELEX utilizes a large ...combinatorial single-stranded oligonucleotide library and progressively selects DNA ligands against whole cells with variable DNA-binding affinities and specificities by repeated rounds of partition and amplification. LIGS exploits the partition step and introduces a secondary, pre-existing high-affinity monoclonal antibody (mAb) ligand to outcompete and elute specific aptamers towards the binding target of the antibody, not the cell. Here, using anti-CD3ε mAb against the cluster of differentiation 3 (CD3ε), as the guiding ligand against one of the domains of the T-cell Receptor (TCR) complex expressed on Jurkat.E6 cells, we discovered three specific aptamers against TCR complex expressed on an immortalized line of human T lymphocyte cells. In sum, we demonstrate that specific aptamers can be identified utilizing an antibody against a single domain of a multidomain protein complex in their endogenous state with neither post- nor pre-SELEX protein manipulation.
Background
We recently demonstrated in humans that the extent of low-dose aspirin (LDA)-induced gastropathy was directly related to the individual gastric acid secretion level. We also established ...reliable cutoff serum pepsinogen (PG) values to predict gastric acid secretion status. In this study, we investigated the clinical usefulness of measuring the serum pepsinogen values for identifying a high-risk group for gastric mucosal injury among chronic LDA users.
Methods
One hundred long-term LDA users were enrolled in this analysis. Serum from each subject was subjected to determination of
H. pylori
status and measurement of pepsinogen values. According to our recent report, a PG I value ≥ 50 ng/mL was defined as estimated hyperchlorhydria in
H. pylori
-negative subjects, while a PG I/II ≥ 3.3 was defined as estimated hyperchlorhydria in
H. pylori
-positive subjects. The grade of gastric mucosal injury was assessed endoscopically, and multiple logistic regression analyses were used to estimate the risk.
Results
Estimated hyperchlorhydria was a strong independent risk for intensive gastric mucosal injury with an OR (95 % CI): 34.0 (4.5–259) and for gastric ulcer with an OR (95 % CI): 10.2 (1.8–58.3) in
H. pylori
-positive subjects, while it was not a significant risk in
H. pylori
-negative subjects. The association persisted even after excluding those with conventional risks for LDA-gastropathy such as ulcer histories.
Conclusion
Using simple serum measurement of
H. pylori
antibody and pepsinogen concentrations, an extremely high-risk group for LDA-induced gastropathy could be extracted, and these patients should become a therapeutic target for prevention of LDA-induced gastropathy.
In this study, a computational fluid dynamics (CFD) analysis conducted to predict the thermo-hydraulic performance of the HTR-10, which is an experimental pebble bed reactor (PBR). The PBR with a ...modular model with a realistic approach and finite volume method (FVM) instead of porous media is used to predict the distribution of the critical thermal-hydraulics parameters like temperature, pressure, velocity, and heat transfer coefficient (HTC) over the pebbles as well as the reactor core. In the simulation study, an optimized mesh used as a replacement of the large size mesh. The simulation results, for the boundary conditions such as coolant inlet and outlet temperatures, mass flow, and other thermal-hydraulics parameters, were validated with the data published by the IAEA benchmark document. This study demonstrates that the CFD analysis using an optimized mesh is capable of predicting the nature thermo-hydraulic behavior of PBR core, maintaining design safety limits like maximum fuel temperature, and coolant flows distribution.
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Purpose
Surface‐guided radiation therapy (SGRT) is a nonionizing imaging approach for patient setup guidance, intra‐fraction monitoring, and automated breath‐hold gating of radiation treatments. SGRT ...employs the premise that the external patient surface correlates to the internal anatomy, to infer the treatment isocenter position at time of treatment delivery. Deformations and posture variations are known to impact the correlation between external and internal anatomy. However, the degree, magnitude, and algorithm dependence of this impact are not intuitive and currently no methods exist to assess this relationship. The primary aim of this work was to develop a framework to investigate and understand how a commercial optical surface imaging system (C‐RAD, Uppsala, Sweden), which uses a nonrigid registration algorithm, handles rotations and surface deformations.
Methods
A workflow consisting of a female torso phantom and software‐introduced transformations to the corresponding digital reference surface was developed. To benchmark and validate the approach, known rigid translations and rotations were first applied. Relevant breast radiotherapy deformations related to breast size, hunching/arching back, distended/deflated abdomen, and an irregular surface to mimic a cover sheet over the lower part of the torso were investigated. The difference between rigid and deformed surfaces was evaluated as a function of isocenter location.
Results
For all introduced rigid body transformations, C‐RAD computed isocenter shifts were determined within 1 mm and 1˚. Additional translational shifts to correct for rotations as a function of isocenter location were determined with the same accuracy. For yaw setup errors, the difference in shift corrections between a plan with an isocenter placed in the center of the breast (BrstIso) and one located 12 cm superiorly (SCFIso) was 2.3 mm/1˚ in lateral direction. Pitch setup errors resulted in a difference of 2.1 mm/1˚ in vertical direction. For some of the deformation scenarios, much larger differences up to 16 mm and 7˚ in the calculated shifts between BrstIso and SCFIso were observed that could lead to large unintended gaps or overlap between adjacent matched fields if uncorrected.
Conclusions
The methodology developed lends itself well for quality assurance (QA) of SGRT systems. The deformable C‐RAD algorithm determined accurate shifts for rigid transformations, and this was independent of isocenter location. For surface deformations, the position of the isocenter had considerable impact on the registration result. It is recommended to avoid off‐axis isocenters during treatment planning to optimally utilize the capabilities of the deformable image registration algorithm, especially when multiple isocenters are used with fields that share a field edge.
SUMMARY
Development of endoscopic submucosal dissection (ESD) improves the en bloc resection rate of superficial esophageal squamous cell carcinoma (SESCC). Although the background mucosa after ESD ...remains malignant potential, esophageal (sub)circumferential ESD, in cases where the mucosal defect is greater than three-fourths of the circumference, might induce refractory stricture, and it may disturb early detection of the recurrence. Therefore, we aimed to elucidate whether the patients treated by (sub)circumferential ESD for SESCC may remain at risk of metachronous recurrence. In a single-center retrospective study, we collected data from 154 consecutive patients who were treated with curative ESD for SESCC from 2002 to 2013 and followed by surveillance for longer than 12 months. Metachronous recurrence was defined as histologically proven SESCC at other site of the ESD scar or abnormal nodal swelling was detected later than 12 months after ESD. The primary endpoint was to identify the risk of metachronous recurrence using multivariate analyses. The secondary endpoint was to investigate difference in clinical pathological features between patients with and without the recurrence. The overall rate of metachronous recurrence was 14.9% during 40.5 median months after the initial ESD. 24.1% and 9.0% of overall metachronous recurrence were observed in patients treated with (sub)circumferential ESD and non-subcircumferential ESD, respectively, despite no significant difference in their observation duration. After the application of a stepwise regression model that included all variants, a Cox proportional hazards regression model identified (sub)circumferential ESD as the only risk for the recurrence (hazard ratio (HR): 1.48, 95% confidence intervals (CI): 1.04–2.08, P = 0.028). The cumulative recurrence rate revealed a significant difference between patients treated by (sub)circumferential ESD and those by nonsubcircumferential ESD (HR: 3.094, 95% CI: 1.33–7.52, P = 0.009), despite no significant difference in their cause-specific survival. Additionally, the session numbers of the follow-up endoscopy until the detection of metachronous recurrence after the non-subcircumferential ESD were significantly less than those after the (sub)circumferential ESD (7.8 ± 1.8 vs. 15.2 ± 1.5 P = 0. 005), despite no significant difference in their cancer-free duration. In conclusion, we demonstrated that patients treated by curative (sub)circumferential ESD for SESCC might be high risk for metachronous recurrence. Therefore, we should establish a risk-stratified surveillance program after (sub)circumferential ESD and preventive strategies for post-ESD stricture.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Purpose
Dose–volume histogram (DVH) measurements have been integrated into commercially available quality assurance systems to provide a metric for evaluating accuracy of delivery in addition to ...gamma analysis. We hypothesize that tumor control probability and normal tissue complication probability calculations can provide additional insight beyond conventional dose delivery verification methods.
Methods
A commercial quality assurance system was used to generate DVHs of treatment plan using the planning CT images and patient‐specific QA measurements on a phantom. Biological modeling was performed on the DVHs produced by both the treatment planning system and the quality assurance system.
Results
The complication‐free tumor control probability, P+, has been calculated for previously treated intensity modulated radiotherapy (IMRT) patients with diseases in the following sites: brain (−3.9% ± 5.8%), head‐neck (+4.8% ± 8.5%), lung (+7.8% ± 1.3%), pelvis (+7.1% ± 12.1%), and prostate (+0.5% ± 3.6%).
Conclusion
Dose measurements on a phantom can be used for pretreatment estimation of tumor control and normal tissue complication probabilities. Results in this study show how biological modeling can be used to provide additional insight about accuracy of delivery during pretreatment verification.
The aim of this randomized controlled trial was to determine the effects of 8-week exercise-intervention on cognition and related serum biochemical markers in nonagenarians. We also studied the ...effects of a 4-week training cessation ('detraining') period on our study variables. Participants were randomly allocated to a standard-care (control) or intervention (exercise) group n=20 (16 women)/group. The intervention focused on supervised, light-to-moderate-intensity aerobic and resistance exercises (mainly leg press), and included 3 weekly sessions. Cognitive status was determined by the mini-mental state examination and geriatric depression scale. We analysed proteins with reported relation with mechanisms behind cognition changes such as serum levels of angiotensin converting enzyme, amyloid-precursor protein, epidermal growth factor, brain-derived neural factor and tumor necrosis factor. No significant change (P>0.05) in any of the variables studied was found following the exercise intervention compared with the standard-care group. Similarly, no significant changes (P>0.05) were observed following the detraining period compared with the standard-care group. Overall changes after the exercise intervention in serum biomarkers were not associated with changes in functional capacity and cognitive measures. An 8-week exercise intervention focusing on resistance exercises neither benefits cognitive function nor affects the levels of the serum proteins analysed in nonagenarians.
Recently, gastric fundic atrophy is reported to be an independent risk factor for esophageal squamous-cell carcinoma (ESCC). The aim of this study is to investigate the acid secretory level in ESCC ...in a case-control study. From April 2004 to March 2008, 100 consecutive subjects with early ESCC and 100 age- and sex-matched asymptomatic controls were prospectively enrolled. Gastrin-stimulated acid output was assessed by endoscopic gastrin test. Conditional regression analyses were used to adjust for other potential confounders. Multivariate analyses revealed a strong association between profound hypochlorhydria and ESCC with odds ratio (95% confidence interval): 6.0 (1.9-18.4). The association remained significant after adjusting for the effect of gastric atrophy as a covariate. The association became stronger as the ESCC developed more distal site of the esophagus. This study indicates that profound hypochlorhydria is a strong independent risk factor for ESCC even after adjusting for the influence of gastric atrophy.
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