12 research outputs found
Discrimination of gamma rays due to inelastic neutron scattering in AGATA
Possibilities of discriminating neutrons and gamma rays in the AGATA
gamma-ray tracking spectrometer have been investigated with the aim of reducing
the background due to inelastic scattering of neutrons in the high-purity
germanium crystals. This background may become a serious problem especially in
experiments with neutron-rich radioactive ion beams. Simulations using the
Geant4 toolkit and a tracking program based on the forward tracking algorithm
were carried out by emitting neutrons and gamma rays from the center of AGATA.
Three different methods were developed and tested in order to find
'fingerprints' of the neutron interaction points in the detectors. In a
simulation with simultaneous emission of six neutrons with energies in the
range 1-5 MeV and ten gamma rays with energies between 150 and 1450 keV, the
peak-to-background ratio at a gamma-ray energy of 1.0 MeV was improved by a
factor of 2.4 after neutron rejection with a reduction of the photopeak
efficiency at 1.0 MeV of only a factor of 1.25.Comment: Accepted for publication in Nuclear Instruments and Methods in
Physics Research, A, 26 May 2009; 13 pages, 5 tables, 12 figure
The antibiotic prescribing behaviors of physicians are changed via rapid antigen test practice in the context of rational drug use
Background/aim: Rapid antigen test (RAT) is a practical test to detect the presence of Group A beta hemolytic streptococcus antigens in throat swab samples. The aim of this study is to investigate the changes in the empiric antibiotic prescribing behavior of 10 family physicians in Kırıkkale Province after using RAT in 2017. Materials and methods: RAT test practice started in Family Medicine in February 2017. Family Medicine Information System (FMIS) includes clinical and prescription records of 10 family physicians, providing health service to approximately 35,000 residents in Kırıkkale. The numbers of antibiotics prescribed by the physicians according to the ICD-10 codes (including upper respiratory tract infections) in February, March, and April of 2015, 2016, 2017 were determined. The number and group of antibiotics prescribed by the family physicians with the determined diagnosis and time periods were specified in the FMIS and recorded. Results: Antibiotic prescription behaviors of family physicians do not show a significant difference between 2015 and 2016. There was a dramatic and significant decrease in the number of prescribed antibiotics in 2017 compared to 2015 and 2016 (P 0.05). Conclusion: This study shows that there has been a significant decrease in antibiotic prescription in 10 Family Medicine departments in 2017 in comparison to February, March, and April 2015 and 2016. The use of RAT resulted in a decrease in antibiotic prescription rates in 2017. © TÜBİTAK
Treatment Evaluation of Flow-Limiting Stenoses of the Superficial Femoral and Popliteal Artery by Parametric Color-Coding Analysis of Digital Subtraction Angiography Series
To evaluate the hemodynamic effect of percutaneous transluminal intervention (PTI) on stenosis of the superficial femoral (SFA) and popliteal arteries (PA) using time-density curves (TDCs) derived from digital subtraction angiography (DSA) series in correlation with ultrasound peak systolic velocity ratio (PSVR) and ankle brachial index (ABI). DSA series of SFA or PA of patients with symptomatic peripheral arterial occlusive disease was obtained with a flat-panel angiography system with intention-to-treat. In DSA series acquired before and after PTI, TDCs were analyzed proximal and distal of each stenosis using parametric color coding (PCC). For correlation, ABI and PSVR measurements pre- and post-PTI were recorded for all patients. In total, 25 stenoses of the SFA or PA were treated by PTI in 22 patients (17 male, 5 female, mean age 68 years). After treatment, peak-to-peak (PTP) times between TDCs proximal and distal to the treated vessel segment decreased statistically significantly (p = 0.01) on average from PTP = 1.9 +/- A 1.7 s to mean PTP = 1 +/- A 1 s. ABI and PSVR also changed statistically significantly after treatment (pretreatment ABI = 0.7 +/- A 0.2, PSVR = 4.2 +/- A 1.9; post-ABI = 0.9 +/- A 0.2, PSVR = 1.3 +/- A 0.4, both p < 0.05). Correlation parameters did not show a strong correlation between change in TDC and clinical parameters ABI and PSVR. Using PCC for analyzing contrast medium dynamics in DSA series is clinically useful for evaluating stenoses of the SFA and PA and for immediate treatment control after PTA
Parenchymal liver blood volume and dynamic volume perfusion CT measurements of hepatocellular carcinoma in patients undergoing transarterial chemoembolization
Aim: Prospective comparison of cone beam C-Arm CT based parenchymal liver blood volume (PLBV) and dynamic volume perfusion CT (dVPCT) measurements in patients with hepatocellular carcinoma (HCC) undergoing transarterial chemoembolisation (TACE) with drug-eluting beads (DEB). Patients and Methods: In 16 patients, changes of PLBV and dVPCT measurements [arterial liver parenchyma (ALP); temporal maximum intensity projection (MIP); hepatic perfusion index (HPI); portal venous parenchyma] were correlated to one another and to the modified Response Evaluation Criteria in Solid Tumors (mRECIST). Results: After TACE, the following parameters showed a statistically significant change (p<0.05) in mean value: PLBV: -4.85 ml/100 ml, ALP: -4.14 ml/100 ml/min, MIP: -0.23 Houndsfield units, HPI: -5.39%, and mRECIST: -20.53 mm. Pre-to-post TACE differences in PLBV showed only weak to very weak correlation to dVPCT parameters (r2<0.24). Conclusion: Although PLBV and dVPCT parameters sho wed only a weak to very weak correlation, both methods validly assessed changes in arterial tumor vascularity after DEB TACE
Neural progenitors proliferation is inhibited by EphB3 in the developing subventricular zone
The subventricular zone (SVZ) of the mammalian forebrain is a major source of multipotent stem cells during development, and contributes to neurogenesis throughout the lifespan of the organism. Several studies described molecules regulating adult neurogenesis, however, few of them have examined neurogenesis in the early postnatal period. Adult neurogenesis is regulated in part by ephrinB3 and its receptors, so we examined the role of EphB3 on neural stem/progenitor cells (NSPCs) proliferation in early postnatal development in the SVZ. To examine NSPCs proliferation, we used BrdU incorporation in both cultured NSPCs and neonatal gene-targeted knockout mice, as well as Ki67 immunostaining in EphB3(−/−) mice. We observed a significant increase in proliferation in cultured NSPCs derived from EphB3(−/−) mice and in the SVZ of EphB3(−/−) mice. These studies support an anti-proliferative role for EphB3 in regulating NSPCs numbers in the developing SVZ
Computed Tomography-Assisted Thoracoscopic Surgery: A Novel, Innovative Approach in Patients With Deep Intrapulmonary Lesions of Unknown Malignant Status
Objectives: Minimally invasive resection of small, deep intrapulmonary lesions can be challenging due to the difficulty of localizing them during video-assisted thoracoscopic surgery (VATS). We report our preliminary results evaluating the feasibility of an image-guided, minimally invasive, 1-stop-shop approach for the resection of small, deep intrapulmonary lesions in a hybrid operating room (OR). Materials and Methods: Fifteen patients (5 men, 10 women; mean age, 63 years) with a total of 16 solitary, deep intrapulmonary nodules of unknown malignant status were identified for intraoperative wire marking. Patients were placed on the operating table for resection by VATS. A marking wire was placed within the lesion under 3D laser and fluoroscopic guidance using a cone beam computed tomography system. Then, wedge resection by VATS was performed in the same setting without repositioning the patient. Results: Complete resection with adequate safety margins was confirmed for all lesions. Marking wire placement facilitated resection in 15 of 16 lesions. Eleven lesions proved to be malignant, either primary or secondary; 5 were benign. Mean lesion size was 7.7 mm; mean distance to the pleural surface was 15.1 mm (mean lesion depth-diameter ratio, 2.2). Mean procedural time for marking wire placement was 35 minutes; mean VATS duration was 36 minutes. Conclusions:Computed tomography-assisted thoracoscopic surgery is a new, safe, and effective procedure for minimally invasive resection of small, deeply localized intrapulmonary lesions. The benefits of computed tomography-assisted thoracoscopic surgery are 1. One-stop-shop procedure, 2. Lower risk for the patient (no patient relocation, no marking wire loss), and 3. No need to coordinate scheduling between the CT room and OR