15 results on '"E. Stancu"'
Search Results
2. Dosimetry Approach of Coronavirus
- Author
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F, Scarlat, primary, E, Stancu, additional, and A, Scarisoreanu, additional
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- 2022
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3. Assessment of Angular Spectral Distributions of Laser Accelerated Particles for Simulation of Radiation Dose Map in Target Normal Sheath Acceleration Regime of High Power Laser-Thin Solid Target Interaction—Comparison with Experiments
- Author
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Alecsandru Chirosca, Bogdan Butoi, E. Stancu, Dragana Biliana Dreghici, Mihai Ganciu, A. Groza, and Mihai Serbanescu
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Photon ,Physics::Optics ,Electron ,01 natural sciences ,lcsh:Technology ,Spectral line ,030218 nuclear medicine & medical imaging ,law.invention ,Ionizing radiation ,lcsh:Chemistry ,03 medical and health sciences ,Acceleration ,0302 clinical medicine ,law ,0103 physical sciences ,General Materials Science ,010306 general physics ,Instrumentation ,lcsh:QH301-705.5 ,Fluid Flow and Transfer Processes ,Physics ,Interaction point ,mapping of radiation dose ,lcsh:T ,Process Chemistry and Technology ,General Engineering ,spectra of laser accelerated particle beams ,Laser ,lcsh:QC1-999 ,Computer Science Applications ,Computational physics ,lcsh:Biology (General) ,lcsh:QD1-999 ,lcsh:TA1-2040 ,GEANT4 simulations ,Vacuum chamber ,lcsh:Engineering (General). Civil engineering (General) ,lcsh:Physics - Abstract
An adequate simulation model has been used for the calculation of angular and energy distributions of electrons, protons, and photons emitted during a high-power laser, 5-µ, m thick Ag target interaction. Their energy spectra and fluencies have been calculated between 0 and 360 degrees around the interaction point with a step angle of five degrees. Thus, the contribution of each ionizing species to the total fluency value has been established. Considering the geometry of the experimental set-up, a map of the radiation dose inside the target vacuum chamber has been simulated, using the Geant4 General Particle Source code, and further compared with the experimental one. Maximum values of the measured dose of the order of tens of mGy per laser shot have been obtained in the direction normal to the target at about 30 cm from the interaction point.
- Published
- 2020
4. Advances in Spectral Distribution Assessment of Laser Accelerated Protons using Multilayer CR-39 Detectors
- Author
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Bogdan Butoi, Adriana Balan, Mihai Serbanescu, Alecsandru Chirosca, Mihai Straticiuc, Bogdan M. Mihalcea, E. Stancu, I. Burducea, Mihai Ganciu, and A. Groza
- Subjects
Materials science ,Spectral power distribution ,Proton ,Calibration curve ,Physics::Instrumentation and Detectors ,Nuclear Theory ,laser-accelerated proton beams ,01 natural sciences ,lcsh:Technology ,010305 fluids & plasmas ,law.invention ,lcsh:Chemistry ,visible light microscopy ,Stack (abstract data type) ,law ,0103 physical sciences ,General Materials Science ,010306 general physics ,Nuclear Experiment ,Instrumentation ,lcsh:QH301-705.5 ,Fluid Flow and Transfer Processes ,Range (particle radiation) ,atomic force microscopy ,lcsh:T ,Process Chemistry and Technology ,Detector ,General Engineering ,Laser ,lcsh:QC1-999 ,Computer Science Applications ,lcsh:Biology (General) ,lcsh:QD1-999 ,lcsh:TA1-2040 ,Physics::Accelerator Physics ,High Energy Physics::Experiment ,Atomic number ,Atomic physics ,lcsh:Engineering (General). Civil engineering (General) ,CR-39 detectors ,lcsh:Physics - Abstract
We show that a spectral distribution of laser-accelerated protons can be extracted by analyzing the proton track diameters observed on the front side of a second CR-39 detector arranged in a stack. The correspondence between the proton track diameter and the incident energy on the second detector is established by knowing that protons with energies only higher than 10.5 MeV can fully deposit their energy in the second CR-39 detector. The correlation between the laser-accelerated proton track diameters observed on the front side of the second CR-39 detector and the proton incident energy on the detector stack is also presented. By calculating the proton number stopped in the CR-39 stack, we find out that its dependence on the proton energy in the 1&ndash, 15 MeV range presents some discontinuities at energies higher than 9 MeV. Thus, we build a calibration curve of the track diameter as a function of the proton incident energy within the 1&ndash, 9 MeV range, and we infer the associated analytical function as the calculations performed indicate best results for proton spectra within the 1&ndash, 9 MeV range. The calibration curve is used as a tool to ascertain the pits identified on the surfaces of both CR-39 detectors to proton tracks. The proton tracks spatial distribution analyzed by optical and atomic force microscopy is correlated with the peculiarity of the used targets.
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- 2019
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5. Genabelte Blasen auf lichtexponierter Haut
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Markus Braun-Falco, Christoph M. Schempp, E. Stancu, and Leena Bruckner-Tuderman
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medicine.medical_specialty ,business.industry ,medicine ,Dermatology ,business - Published
- 2007
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6. [Umbilicated blisters on sun-exposed skin]
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E, Stancu, M, Braun-Falco, L, Bruckner-Tuderman, and C M, Schempp
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Male ,Blister ,Treatment Outcome ,Adolescent ,Sunlight ,Humans ,Hydroa Vacciniforme ,Desoxycorticosterone - Published
- 2006
7. 1016 Validation of radiation therapy oncology group (RTOG) recursive partitioning analysis (RPA) classes for patients with brain metastases: A single center experience with 647 cases
- Author
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Roland Guttenberger, E. Stancu, G. Witucki, Johannes Lutterbach, and Hermann Frommhold
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Oncology ,Cancer Research ,medicine.medical_specialty ,Radiation ,Group (mathematics) ,business.industry ,medicine.medical_treatment ,Recursive partitioning ,Single Center ,Radiation therapy ,Internal medicine ,medicine ,Radiology, Nuclear Medicine and imaging ,Medical physics ,business - Published
- 1999
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8. CONTRIBUTIONS TO THE SALINITY CONTROL OF GREENHOUSES SOILS BY MEANS OF WASHING
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M. Dracea, A.L. Maianu, E. Stancu, and I. Bengulescu
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Soil water ,Environmental engineering ,Environmental science ,Greenhouse ,Horticulture ,Soil salinity control - Published
- 1977
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9. Drug-Drug Interactions in Nosocomial Infections: An Updated Review for Clinicians.
- Author
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Hîncu S, Apetroaei MM, Ștefan G, Fâcă AI, Arsene AL, Mahler B, Drăgănescu D, Tăerel AE, Stancu E, Hîncu L, Zamfirescu A, and Udeanu DI
- Abstract
Prevention, assessment, and identification of drug-drug interactions (DDIs) represent a challenge for healthcare professionals, especially in nosocomial settings. This narrative review aims to provide a thorough assessment of the most clinically significant DDIs for antibiotics used in healthcare-associated infections. Complex poly-pharmaceutical regimens, targeting multiple pathogens or targeting one pathogen in the presence of another comorbidity, have an increased predisposition to result in life-threatening DDIs. Recognising, assessing, and limiting DDIs in nosocomial infections offers promising opportunities for improving health outcomes. The objective of this review is to provide clinicians with practical advice to prevent or mitigate DDIs, with the aim of increasing the safety and effectiveness of therapy. DDI management is of significant importance for individualising therapy according to the patient, disease status, and associated comorbidities.
- Published
- 2024
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10. First in vitro cell co-culture experiments using laser-induced high-energy electron FLASH irradiation for the development of anti-cancer therapeutic strategies.
- Author
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Orobeti S, Sima LE, Porosnicu I, Diplasu C, Giubega G, Cojocaru G, Ungureanu R, Dobrea C, Serbanescu M, Mihalcea A, Stancu E, Staicu CE, Jipa F, Bran A, Axente E, Sandel S, Zamfirescu M, Tiseanu I, and Sima F
- Subjects
- Humans, Cell Line, Tumor, Melanocytes radiation effects, DNA Damage, Melanoma radiotherapy, Melanoma pathology, DNA Breaks, Double-Stranded radiation effects, Coculture Techniques methods, Electrons, Lasers
- Abstract
Radiation delivery at ultrahigh dose rates (UHDRs) has potential for use as a new anticancer therapeutic strategy. The FLASH effect induced by UHDR irradiation has been shown to maintain antitumour efficacy with a reduction in normal tissue toxicity; however, the FLASH effect has been difficult to demonstrate in vitro. The objective to demonstrate the FLASH effect in vitro is challenging, aiming to reveal a differential response between cancer and normal cells to further identify cell molecular mechanisms. New high-intensity petawatt laser-driven accelerators can deliver very high-energy electrons (VHEEs) at dose rates as high as 10
13 Gy/s in very short pulses (10-13 s). Here, we present the first in vitro experiments carried out on cancer cells and normal non-transformed cells concurrently exposed to laser-plasma accelerated (LPA) electrons. Specifically, melanoma cancer cells and normal melanocyte co-cultures grown on chamber slides were simultaneously irradiated with LPA electrons. A non-uniform dose distribution on the cell cultures was revealed by Gafchromic films placed behind the chamber slide supporting the cells. In parallel experiments, cell co-cultures were exposed to pulsed X-ray irradiation, which served as positive controls for radiation-induced nuclear DNA double-strand breaks. By measuring the impact on discrete areas of the cell monolayers, the greatest proportion of the damaged DNA-containing nuclei was attained by the LPA electrons at a cumulative dose one order of magnitude lower than the dose obtained by pulsed X-ray irradiation. Interestingly, in certain discrete areas, we observed that LPA electron exposure had a different effect on the DNA damage in healthy normal human epidermal melanocyte (NHEM) cells than in A375 melanoma cells; here, the normal cells were less affected by the LPA exposure than cancer cells. This result is the first in vitro demonstration of a differential response of tumour and normal cells exposed to FLASH irradiation and may contribute to the development of new cell culture strategies to explore fundamental understanding of FLASH-induced cell effect., (© 2024. The Author(s).)- Published
- 2024
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11. Dietary Influence on Drug Efficacy: A Comprehensive Review of Ketogenic Diet-Pharmacotherapy Interactions.
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Marinescu SCN, Apetroaei MM, Nedea MII, Arsene AL, Velescu BȘ, Hîncu S, Stancu E, Pop AL, Drăgănescu D, and Udeanu DI
- Subjects
- Humans, Biological Availability, Cardiovascular Agents pharmacokinetics, Chronic Disease drug therapy, Chronic Disease therapy, Drug Interactions, Hypoglycemic Agents pharmacokinetics, Diet, Ketogenic, Food-Drug Interactions, Ketosis metabolism
- Abstract
It is widely acknowledged that the ketogenic diet (KD) has positive physiological effects as well as therapeutic benefits, particularly in the treatment of chronic diseases. Maintaining nutritional ketosis is of utmost importance in the KD, as it provides numerous health advantages such as an enhanced lipid profile, heightened insulin sensitivity, decreased blood glucose levels, and the modulation of diverse neurotransmitters. Nevertheless, the integration of the KD with pharmacotherapeutic regimens necessitates careful consideration. Due to changes in their absorption, distribution, metabolism, or elimination, the KD can impact the pharmacokinetics of various medications, including anti-diabetic, anti-epileptic, and cardiovascular drugs. Furthermore, the KD, which is characterised by the intake of meals rich in fats, has the potential to impact the pharmacokinetics of specific medications with high lipophilicity, hence enhancing their absorption and bioavailability. However, the pharmacodynamic aspects of the KD, in conjunction with various pharmaceutical interventions, can provide either advantageous or detrimental synergistic outcomes. Therefore, it is important to consider the pharmacokinetic and pharmacodynamic interactions that may arise between the KD and various drugs. This assessment is essential not only for ensuring patients' compliance with treatment but also for optimising the overall therapeutic outcome, particularly by mitigating adverse reactions. This highlights the significance and necessity of tailoring pharmacological and dietetic therapies in order to enhance the effectiveness and safety of this comprehensive approach to managing chronic diseases.
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- 2024
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12. The Effects of Electron Beam Irradiation on the Morphological and Physicochemical Properties of Magnesium-Doped Hydroxyapatite/Chitosan Composite Coatings.
- Author
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Bita B, Stancu E, Stroe D, Dumitrache M, Ciobanu SC, Iconaru SL, Predoi D, and Groza A
- Abstract
This work reports on the influence of 5 MeV electron beam radiations on the morphological features and chemical structure of magnesium-doped hydroxyapatite/chitosan composite coatings generated by the magnetron sputtering technique. The exposure to ionizing radiation in a linear electron accelerator dedicated to medical use has been performed in a controllable manner by delivering up to 50 Gy radiation dose in fractions of 2 Gy radiation dose per 40 s. After the irradiation with electron beams, the surface of layers became nano-size structured. The partial detachment of irradiated layers from the substrates has been revealed only after visualizing their cross sections by scanning electron microscopy. The energy dispersive X-ray spectral analysis of layer cross-sections indicated that the distribution of chemical elements in the samples depends on the radiation dose. The X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction analysis have shown that the physicochemical processes induced by the ionizing radiation in the magnesium doped hydroxyapatite/chitosan composite coatings do not alter the apatite structure, and Mg remains bonded with the phosphate groups.
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- 2022
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13. Y 2 O 3 Nanoparticles and X-ray Radiation-Induced Effects in Melanoma Cells.
- Author
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Porosnicu I, Butnaru CM, Tiseanu I, Stancu E, Munteanu CVA, Bita BI, Duliu OG, and Sima F
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- Cell Line, Tumor, Cell Proliferation drug effects, Cell Proliferation radiation effects, Cell Survival drug effects, Cell Survival radiation effects, Dose-Response Relationship, Radiation, Humans, Melanoma therapy, Mitochondria drug effects, Nanoparticles, Particle Size, Photochemotherapy, Proteomics, Melanoma metabolism, Mitochondria metabolism, Reactive Oxygen Species metabolism, Yttrium pharmacology
- Abstract
The innovative strategy of using nanoparticles in radiotherapy has become an exciting topic due to the possibility of simultaneously improving local efficiency of radiation in tumors and real-time monitoring of the delivered doses. Yttrium oxide (Y
2 O3 ) nanoparticles (NPs) are used in material science to prepare phosphors for various applications including X-ray induced photodynamic therapy and in situ nano-dosimetry, but few available reports only addressed the effect induced in cells by combined exposure to different doses of superficial X-ray radiation and nanoparticles. Herein, we analyzed changes induced in melanoma cells by exposure to different doses of X-ray radiation and various concentrations of Y2 O3 NPs. By evaluation of cell mitochondrial activity and production of intracellular reactive oxygen species (ROS), we estimated that 2, 4, and 6 Gy X-ray radiation doses are visibly altering the cells by inducing ROS production with increasing the dose while at 6 Gy the mitochondrial activity is also affected. Separately, high-concentrated solutions of 25, 50, and 100 µg/mL Y2 O3 NPs were also found to affect the cells by inducing ROS production with the increase of concentration. Additionally, the colony-forming units assay evidenced a rather synergic effect of NPs and radiation. By adding the NPs to cells before irradiation, a decrease of the number of proliferating cell colonies was observed with increase of X-ray dose. DNA damage was evidenced by quantifying the γ-H2AX foci for cells treated with Y2 O3 NPs and exposed to superficial X-ray radiation. Proteomic profile confirmed that a combined effect of 50 µg/mL Y2 O3 NPs and 6 Gy X-ray dose induced mitochondria alterations and DNA changes in melanoma cells.- Published
- 2021
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14. On within sample homogeneity testing using gamma-ray spectrometry.
- Author
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Suvaila R, Stancu E, and Sima O
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- Brazil, Radiation Dosage, Sample Size, Algorithms, Artifacts, Barium Radioisotopes analysis, Barium Radioisotopes standards, Radiometry standards, Specimen Handling instrumentation, Spectrometry, Gamma standards
- Abstract
Several problems concerning (133)Ba activity distribution in a cylindrical source were addressed by measurements with a 47% n-type HPGe detector and by simulation. Within-sample homogeneity was tested using the count rates from normal and from pure sum peaks. The sensitivity of front versus back source measurements to deviations from uniform distribution was studied. In the case of distributions symmetric with respect to the median plane of the source quantities that can provide information on the distribution of the activity were proposed., (Copyright © 2012 Elsevier Ltd. All rights reserved.)
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- 2012
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15. Patients with brain metastases: hope for recursive partitioning analysis (RPA) class 3.
- Author
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Lutterbach J, Bartelt S, Stancu E, and Guttenberger R
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- Adult, Aged, Aged, 80 and over, Brain Neoplasms classification, Brain Neoplasms mortality, Female, Humans, Karnofsky Performance Status, Male, Middle Aged, Multivariate Analysis, Prognosis, Retrospective Studies, Survival Analysis, Brain Neoplasms radiotherapy, Brain Neoplasms secondary
- Abstract
Purpose: The objectives of the present study were (a) to validate the prognostic classification derived from recursive partitioning analysis (RPA) of the Radiation Therapy Oncology Group (RTOG); (b) to identify prognostic factors in class 3; (c) to examine the impact of treatment related variables on the prognosis in class 3., Patients and Methods: Nine hundred and sixteen patients with brain metastases had resection and whole brain radiotherapy (WBRT, n = 257) or WBRT alone (n = 659) at our institution from 1985 to 2000. Patients were grouped into RPA classes 1, 2, and 3 (n = 67, 441, and 408, respectively)., Results: Median survival of the whole group was 3.4 months. Median survival in classes 1, 2, and 3 was 8.2, 4.9, and 1.8 months, respectively. In class 3, age (<65 years vs. > or =65 years, relative risk (RR) 0.75), status of the primary tumor (controlled vs. uncontrolled, RR 0.86), and the number of brain metastases (single vs. multiple, RR 0.76) were independent prognostic variables. We defined three prognostic subgroups: class 3a (n = 51): age <65 years, controlled primary tumor, single brain metastasis; class 3c (n = 44): age > or =65 years, uncontrolled primary tumor, multiple brain metastases; class 3b (n = 313): all other patients. Median survival in classes 3a, 3b, and 3c was 3.2, 1.9, and 1.2 months, respectively (P < 0.0001). Intra-class comparisons showed that resection followed by WBRT yielded significantly better survival compared with WBRT alone., Conclusion: Our results validate the RTOG RPA classification for patients with brain metastases. The variables age, status of the primary, and number of brain metastases allow the division of class 3 into prognostic subgroups. Even class 3 patients may benefit from more aggressive treatment strategies., (Copyright 2002 Elsevier Science Ireland Ltd.)
- Published
- 2002
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