Charged State of a Spherical Plasma in Vacuum

The stationary state of a spherically symmetric plasma configuration is investigated in the limit of immobile ions and weak collisions. Configurations with small radii are positively charged as a significant fraction of the electron population evaporates during the equilibration process, leaving behind an electron distribution function with an energy cutoff. Such charged plasma configurations are of interest for the study of Coulomb explosions and ion acceleration from small clusters irradiated by ultraintense laser pulses and for the investigation of ion bunches propagation in a plasma

Combustion synthesis and upconversion luminescence properties of Er3+, Yb3+ doped gadolinium oxide nanophosphor

Gd2O3: Er3+, Yb3+ Nanophosphor prepared by combustion synthesis method.  Optical and Upconversion luminescence properties of rare earth doped nanophosphors were studied. The nanophosphors were characterized using Scanning electron microscopy, X-ray diffraction and ultraviolet–visible absorption spectroscopy. The results of XRD show cubic phase can be obtained, the average crystalline size could be calculated as 38 and 49nm respectively, which coincided with the results from SEM images. The UV- Vis optical spectra were also studied. Upconversion luminescence spectra of samples under the range of 980 nm, excitation were investigated. The strong red and weak green emission was observed. The possible upconversion luminescence mechanisms for Er3+, Yb3+ doped gadolinium nanophosphor were also discussed

Thermoluminescence Study of Y2O3: Tb

Nanophosphors were prepared by the combustion technique using yttria and terbia powder as precursors and urea as fuels. The particle is investigated by X-ray diffraction analysis. X-ray diffraction patterns confirm the formation of pure cubic phase of Y2O3 .The resulting product was characterized by FTIR spectra to evaluate the vibrational feature of the sample. TL emission spectra show intense peak around 520 nm

Optical properties of calcium aluminate phosphors

Thermoluminescence properties of CaAl2O4 was studied. It was found that firstly the TL intensity increases with increase in UV irradiation time and it attains a maximum value for 20 minute irradiation time. TL intensity decreases with further increase in irradiation time

Thermoluminescence of ï§-irradiated SrAl2O4:Dy

Thermoluminescence (TL) properties of ï§-irradiated Strontium Aluminate doped with Dy (10% molar concentration) was studied. The phosphor was synthesized by combustion method using urea as a reducer at initiating temperature of 600oC.  Dy doped SrAl2O4 is a good dosimeter having linear response upto 2360 Gy of ï§-dose. The kinetic parameter have been calculated using Chen’s glow curve method

Idiopathic osteonecrosis of the medial tibial plateau

Osteonecrosis of the medial tibial plateau is characterized by acute pain on the medial aspect of the knee. Progression can lead to articular collapse and requires early diagnosis and treatment. We studied seven patients affected of idiopathic osteonecrosis of the tibial plateau. The mean age was 62 years and the mean follow-up 42 months. We performed roentgenograms in all patients, bone scans in three patients and magnetic resonance image (MRI) in five. MRI shows T1-weighted low-intensity signal and T2-weighted high-intensity signal with a surrounding area of intermediate low-intensity signal. An increased focal uptake was seen at bone scan. Histological findings showed necrotic bone with empty lacunae. Surgical treatment consisted of tibial subchondral drilling in four patients-two of them by failure of conservative treatment, and a total knee arthroplasty in other two. One patient had a satisfactory evolution with conservative treatment. Idiopathic osteonecrosis of the tibial plateau must be considered in elderly patients with knee pain over the medial tibial plateau. At early stages, decompression with tibial drilling must be considered. This procedure allows a prompt and effective relief of symptom

Dose escalation to high-risk sub-volumes based on non-invasive imaging of hypoxia and glycolytic activity in canine solid tumors:a feasibility study

INTRODUCTION: Glycolytic activity and hypoxia are associated with poor prognosis and radiation resistance. Including both the tumor uptake of 2-deoxy-2-[(18) F]-fluorodeoxyglucose (FDG) and the proposed hypoxia tracer copper(II)diacetyl-bis(N(4))-methylsemithio-carbazone (Cu-ATSM) in targeted therapy planning may therefore lead to improved tumor control. In this study we analyzed the overlap between sub-volumes of FDG and hypoxia assessed by the uptake of (64)Cu-ATSM in canine solid tumors, and evaluated the possibilities for dose redistribution within the gross tumor volume (GTV). MATERIALS AND METHODS: Positron emission tomography/computed tomography (PET/CT) scans of five spontaneous canine solid tumors were included. FDG-PET/CT was obtained at day 1, (64)Cu-ATSM at day 2 and 3 (3 and 24 h pi.). GTV was delineated and CT images were co-registered. Sub-volumes for 3 h and 24 h (64)Cu-ATSM (Cu3 and Cu24) were defined by a threshold based method. FDG sub-volumes were delineated at 40% (FDG40) and 50% (FDG50) of SUV(max). The size of sub-volumes, intersection and biological target volume (BTV) were measured in a treatment planning software. By varying the average dose prescription to the tumor from 66 to 85 Gy, the possible dose boost (D( B )) was calculated for the three scenarios that the optimal target for the boost was one, the union or the intersection of the FDG and (64)Cu-ATSM sub-volumes. RESULTS: The potential boost volumes represented a fairly large fraction of the total GTV: Cu3 49.8% (26.8-72.5%), Cu24 28.1% (2.4-54.3%), FDG40 45.2% (10.1-75.2%), and FDG50 32.5% (2.6-68.1%). A BTV including the union (∪) of Cu3 and FDG would involve boosting to a larger fraction of the GTV, in the case of Cu3∪FDG40 63.5% (51.8-83.8) and Cu3∪FDG50 48.1% (43.7-80.8). The union allowed only a very limited D( B ) whereas the intersection allowed a substantial dose escalation. CONCLUSIONS: FDG and (64)Cu-ATSM sub-volumes were only partly overlapping, suggesting that the tracers offer complementing information on tumor physiology. Targeting the combined PET positive volume (BTV) for dose escalation within the GTV results in a limited D( B ). This suggests a more refined dose redistribution based on a weighted combination of the PET tracers in order to obtain an improved tumor control

Effect of firing temperature on the particles size of Gd2O3: Eu doped nanophosphors

The paper reports that synthesis and characterization of Eu2+ doped Gd2O3 nanophosphors prepared by combustion synthesis. It has been reported that the effect of synthesis temperature on particle size dependence phenomenon of rare earth doped nanophosphors. The sample was characterized by XRD pattern and FTIR study. Synthesized sample shows cubic structure verified by the XRD results.  Size of the particle was caculated by scherer equation the avarage size obtained 15, 23 and 55 at 4000C, 5000C and 6000C respectively. In this synthesis urea used as a fuel for created reducing atmosphere during sample preparation.&nbsp

Mechanoluminescence properties of SrAl2O4: Tb3+ phosphor

Through the execution of experimental investigation, Mechanoluminescence of SrAl2O4:Tb3+ phosphor was studied which is synthesized by combustion method. In the observation, the peak value of ML depends on the different impact velocity. It was seen that at 55 cm height, the maximum peak of ML is obtained.&nbsp

Thermoluminescence and Mechanoluminescence studies of (Cd0.95 Zn0.05)S: Ag doped phosphor

Through the execution of experimental investigation, mechanoluminescence of (Cd,Zn)S: Ag phosphor was studied which is synthesized by solid state reaction. In the observation, the peak value of ML depends on different concentration. It is seen that ML intensity increases with Ag ion concentration in (Cd, Zn)S phosphor. The peak value of TL depends on the different UV-irradiation time. It is seen that as UV-irradiation exposure increases the TL intensity also increases