WorldWideScience
 
 
2

Processing and characterization of chitosan microspheres to be used as templates for layer-by-layer assembly  

British Library Electronic Table of Contents (United Kingdom)

Chitosan (Ch) microspheres have been developed by precipitation method, cross-linked with glutaraldehyde and used as a template for layer-by-layer (LBL) deposition of two natural polyelectrolytes. Using a LBL methodology, Ch microspheres were alternately coated with hyaluronic acid (HA) and Ch under mild conditions. The roughness of the Ch-based crosslinked microspheres was characterized by atomic force microscopy (AFM). Morphological characterization was performed by environmental scanning electron microscopy (ESEM), scanning electron microscopy (SEM) and stereolight microscopy. The swelling behaviour of the microspheres demonstrated that the ones with more bilayers presented the highest water uptake and the uncoated cross-linked Ch microspheres showed the lowest uptake capability. Micros...

2010-01-01

3

Composition, morphology, properties of coal fly ash microspheres and their application for conditioning liquid radioactive waste  

International Nuclear Information System (INIS)

Using methods of the Moessbauer spectroscopy, scanning electron microscopy, and thermodynamic analysis of phase formation in silicate multi-component melts, the detailed study of composition, morphology, and properties of fly ash microspheres resulting from combustion of three coals (Irsha-Borodinskii, Kuznetskii and Ekibastuzskii) was carried out. About 60 microspherical products with an iron content of 2-94 wt.% Fe_2O_3 were obtained. The ranges of microsphere composition, suitable for liquid radioactive waste solidification in the forms of iron phosphate (36-94 wt.% Fe_2O_3) and aluminosilicate (2-20 wt.% Fe_2O_3) ceramics were determined. The possibility of producing porous materials and specific microspherical sorbents, based on coal fly ash cenospheres and their application for mobilisation of liquid radioactive waste solidification was demonstrated. (author)

4

Physical and electrochemical characterization of CdS hollow microspheres prepared by a novel template free solution phase method  

International Nuclear Information System (INIS)

Novel CdS hollow microspheres have been successfully synthesized via a facile template-free solution-phase reaction from cadmium nitrate and thioacetamide precursors. The morphology of CdS hollow microspheres depends strongly on the ratio between the precursors, cadmium nitrate to thioacetamide ratio. The physical properties of the hollow microspheres have systematically been studied by different characterization methods. The stoichiometry of the hollow microspheres studied by the energy dispersive X-ray diffraction spectroscopy confirmed that the synthesized CdS hollow microspheres are nearly stoichiometric bulk like CdS. The morphology of the hollow microspheres studied by high resolution scanning electron microscopy and transmission electron microscopy observations showed that the CdS hollow microspheres of the size of 2.5 ?m have hollow ...

2010-12-15

5

Preparation and biodistribution of yttrium-90 lipiodol in rats following hepatic arterial injection  

Energy Technology Data Exchange (ETDEWEB)

We labelled Lipiodol with yttrium-90 and analysed the biodistribution in rats after intrahepatic arterial injection. An RP-18 column was used to separate {sup 90}Y from strontium-90. {sup 90}Y was retained on the column, which had been pretreated with yttrium-selective extraction reagent, di(2-ethylhexyl) phosphate, while {sup 90}Sr was washed out. A hexadentate nitrogen-donor chelating ligand N,N,N`,N`-tetrakis(2-benzymidazolylmethyl)-1,2-ethanediamine (EDTB) was synthesized by condensation of 1,2-benzenediamine and ethylene diamine tetra-acetic acid (EDTA). Lipiodol was covalently conjugated with EDTB. The final product was obtained by eluting the retained {sup 90}Y from the RP-18 column with EDTB-Lipiodol. Sixteen male rats (Sprague-Dawley) were sacrificed at 1 h, 24 h, 48 h and 72 h (four rats at each time) after injection of approximately 0.1 mCi {sup 90}Y-Lipiodol via the hepatic artery. Samples of liver, spleen, muscle, lung, kidney, ...

1995-03-01

6

Utilization of Fluorescent Microspheres and a Green Fluorescent Protein-Marked Strain for Assessment of Microbiological Contamination of Permafrost and Ground Ice Core Samples from the Canadian High Arctic  

UK PubMed Central (United Kingdom)

Fluorescent microspheres were applied in a novel fashion during subsurface drilling of permafrost and ground ice in the Canadian High Arctic to monitor the exogenous microbiological contamination of...Full Text Available

2005-02-01

7

Evaluation of chitosan/beta-tricalcium phosphate microspheres as a constituent to PMMA cement.  

Science.gov (United States)

Two methods, a traditional emulsion technique and a high voltage electrostatically modified encapsulation system, were used to fabricate degradable chitosan/beta -tricalcium phosphate (beta-TCP) microspheres. The two distinct kinds of microspheres both exhibited good sphericity and the beta-TCP was trapped well inside the chitosan gel. The microspheres prepared by high voltage electrostatic system exhibited a rougher outer surface and narrower size distribution. These microspheres were then used as an added constituent to commercially available PMMA bone cement. Four modified cement composites that were prepared with different composition ratios of the two kinds of chitosan/beta-TCP microspheres that were made from emulsion technique (C1P1 and C2P1) and from a process by a high voltage electrostatic system (EC1P1 and EC2P1) were compared with the PMMA cement (Pure P). The ...

2005-06-01

8

Comparative effects of scaffold pore size, pore volume, and total void volume on cranial bone healing patterns using microsphere-based scaffolds  

UK PubMed Central (United Kingdom)

Bony craniofacial deficits resulting from injury, disease, or birth defects remain a considerable clinical challenge. In this study, microsphere-based scaffold fabrication methods were use to...Full Text Available

2009-06-01

9

Whispering gallery modes in silicon-nanocrystal-coated silica microspheres  

Energy Technology Data Exchange (ETDEWEB)

Silica microspheres were deposited into two-dimensional periodic arrays and coated with a thin layer of silicon nanocrystals. The luminescence from the silicon nanocrystals coupled into the whispering gallery modes of the spheres, with Q factors that depended on a range of parameters including sphere size, position on the sphere, viewing direction, and thickness of the nanocrystal coating. Scattering from the film-sphere and/or the sphere-substrate contacts resulted in a lower Q for modes that intersect these regions. The highest Q factors obtained in this work were {approx}1500. The results suggest that silica microspheres may be promising candidates for high-Q cavities that incorporate silicon nanocrystals for cavity QED or nonlinear optical effects.

2007-10-15

10

Evaluation of Multiplexed Fluorescent Microsphere Immunoassay for Detection of Autoantibodies to Nuclear Antigens  

UK PubMed Central (United Kingdom)

Antibodies to extractable nuclear antigens (ENA) are found in a variety of collagen vascular diseases. Determining the individual specificities of these antibodies is extremely useful in establishing...Full Text Available

2004-11-01

11

Labeled cells as research, diagnostic and therapeutic tools  

Energy Technology Data Exchange (ETDEWEB)

Scientists at JPL have developed chemical and biological techniques using microspheres filled with drugs, electron-opaque metals, or radioactive, fluorescent, magnetic or electrically charged materials to label specific groups of cells. Synthetic polymeric microspheres are coupled with specific antibodies to form reagents called immunomicrospheres, which can seek out and attach themselves to any specific group of cells. These cell-labeling techniques, therefore, open new avenues not only to the basic study of cells but also to the diagnosis and treatment of many diseases, including cancer.

1983-09-01

12

Suppression of glycosaminoglycan synthesis by articular cartilage, but not of hyaluronic acid synthesis by synovium, after exposure to radiation  

International Nuclear Information System (INIS)

We recently found that injection of 2 mCi of yttrium 90 (90Y; approximately 23,000 rads) into normal canine knees stimulated glycosaminoglycan (GAG) synthesis by femoral condylar cartilage. The present investigation was conducted to determine whether radiation affects cartilage metabolism directly. Rates of GAG synthesis and degradation in normal canine articular cartilage were studied following irradiation. Cultured synovium from the same knees was treated similarly, to determine the effects of irradiation on hyaluronic acid synthesis. Twenty-four hours after exposure to 1,000 rads, 10,000 rads, or 50,000 rads, 35S-GAG synthesis by the cartilage was 93%, 69%, and 37%, respectively, of that in control, nonirradiated cartilage. The effect was not rapidly reversible: 120 hours after exposure to 50,000 rads, GAG synthesis remained at only 28% of the control level. Autoradiography showed marked suppression of 35S uptake by chondrocytes after ...

1989-01-01

13

Pre-therapy 18F-FDG PET quantitative parameters help in predicting the response to radioimmunotherapy in non-Hodgkin lymphoma  

International Nuclear Information System (INIS)

Radioimmunotherapy (RIT) is a new treatment option for patients with non-Hodgkin lymphoma (NHL). Response to RIT currently remains difficult to predict using conventional prognostic factors and could be refined using functional imaging. The goal of this work is to evaluate the value of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in predicting response to Yttrium 90-labeled monoclonal antibodies for patients with NHL. Thirty-five patients with NHL who had undergone 18F-FDG PET prior to RIT with either 90Y-ibritumomab tiuxetan (group A; n=17) or 90Y-epratuzumab tetraxetan (group B; n=18) were included in this retrospective study. Four functional criteria were determined for each tumour lesion in a given patient: maximum and mean standard uptake values (SUVmax and SUVmean), functional lesion volume (LVol) and total lesion glycolysis (TLG, product of the volume and the SUVmean). For each patient, we determined highest SUVmax and ...

2010-03-01

14

Two-step template-free route for synthesis of TiO2 hollow spheres  

British Library Electronic Table of Contents (United Kingdom)

The TiO2 hollow microspheres were prepared by microwave-assisted solvothermal treatment without template. The morphology and the phase of TiO2 hollow microspheres were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), and BET surface areas. The results show that the particles have hollow structures and the shell was covered by nanocrystals and have higher specific surface area. The possible formation mechanism of hollow TiO2 spherical structures has simply been proposed. The activity was evaluated by the photocatalytic degradation of methyl orange (MO). The results show that the particles having specific surface area show higher photocatalytic activity. It can be attribute to the doped ...

2011-01-01

15

Synthesis and electrorheological characteristics of sea urchin-like TiO2 hollow spheres  

British Library Electronic Table of Contents (United Kingdom)

TiO2 hollow microspheres with sea urchin-like hierarchical architectures were synthesized by a simple hydrothermal method. The as-synthesized hollow microspheres with hierarchical architectures consisting of many rhombic building units exhibit high specific surface area. Electrorheological (ER) properties of hierarchical hollow TiO2-based suspension were investigated under steady and oscillatory shear. The hollow TiO2-based suspensions show much higher yield stress and elasticity than pure TiO2 suspension at the same electric field strength. This phenomenon was elucidated well in view of their dielectric spectra analysis. The sea urchin-like architectures result in stronger interfacial polarization of hollow TiO2 suspension upon an electric field, showing higher ER activity. Also, hollow i...

2011-01-01

16

Soluble starch?based biodegradable and microporous microspheres as potential adsorbent for stabilization and controlled release of coix seed oil  

British Library Electronic Table of Contents (United Kingdom)

Soluble starch?based biodegradable and microporous microspheres (SDM-Ms) were prepared by emulsion chemical cross-linking technique using trisodium trimetaphosphate (TSTP) as the cross-linker. The resultant amorphous SDM-Ms were excellently identified by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The internal rupture and surface-controlled erosion were the predominant degradation mechanisms for SDM-Ms. The obtained SDM-Ms were applied to adsorb coix seed oil (CSO) by immersing method. The adsorption capacity of CSO within SDM-Ms was determined, namely 0.5238?g/g, and the thermal stability was shown higher than that of the free CSO. A burst release appeared in the second hour, followed by controlled release. Diffusion, d...

2011-01-01

17

Trans-arterial chemo-embolization (TACE), with either lipiodol (traditional TACE) or drug-eluting microspheres (precision TACE, pTACE) in the treatment of hepatocellular carcinoma: efficacy and safety results from a large mono-institutional analysis  

UK PubMed Central (United Kingdom)

More data about TACE and pTACE seem necessary to better define the global treatment strategy for HCC. Aim of our analysis was to evaluate the role of TACE, either with lipiodol (traditional) or drug-eluting...Full Text Available

18

Simultaneous Detection of Multiplex-Amplified Human Immunodeficiency Virus Type 1 RNA, Hepatitis C Virus RNA, and Hepatitis B Virus DNA Using a Flow Cytometer Microsphere-Based Hybridization Assay  

UK PubMed Central (United Kingdom)

The feasibility of performing a multiplex assay for the detection of human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) RNAs and hepatitis B virus (HBV) DNA is demonstrated. This...Full Text Available

2000-03-01

19

Review of experience gained in fabricating nuclear grade uranium and thorium compounds and their analytical quality control at the Instituto de Energia Atomica, Sao Paulo, Brazil  

International Nuclear Information System (INIS)

The main activities developed at 'Instituto de Energia Atomica' Sao Paulo, Brazil, on the recovery of uranium from ores, the purification of uranium and thorium raw concentrates and their transformation in nuclear grade compounds, are reviewed. The design and assemble of pilot facilities for ammonium diuranate (ADV) uranium tetrafluoride, uranium trioxide, uranium oxide microspheres, uranyl nitrate denitration, uranim hexafluoride and thorium compounds are discussed. The establishment of analytical procedures are emphasized.

1980-08-22

20

Refractometry of organosilica microspheres  

CERN Document Server

The refractive index of novel organosilica (nano/micro)material is determined using two methods. The first method is based on analysis of optical extinction efficiency of organosilica beads versus wavelength, which is obtained by a standard laboratory spectrometer. The second method relies on the measurable trapping potential of these beads in the focused light beam (laser tweezers). Polystyrene beads were used to test these methods, and the determined dispersion curves of refractive index values have been found accurate. The refractive index of organosilica beads has been determined to range from 1.60-1.51 over the wavelength range of 300-1100 nm.

2007-01-01

 
 
 
 
21

Heat capacity measurement of some breeder materials  

International Nuclear Information System (INIS)

Isobaric molar heat capacities of powder and microsphere form of Li2TiO3 (s) and powder form of LiAlO2 (s) and Li2ZrO3 (s) were measured using a heat flux type differential scanning calorimeter in the temperature range 320 - 870 K. Specific heat capacities of LiAlO2 (s) was found to be much larger compared to those of Li2TiO3 (s) and Li2ZrO3 (s). (author)

2009-01-07

22

Determining nuclear morphology using an improved angle-resolved low coherence interferometry system  

Science.gov (United States)

We outline the process for determining the morphology of subsurface epithelial cell nuclei using depth-resolved light scattering measurements. The measurements are accomplished using a second generation angle-resolved low coherence interferometry system. The new system greatly improves data acquisition and analysis times compared to the initial prototype system. The calibration of the new system is demonstrated in scattering studies to determine the size distribution of polystyrene microspheres in a turbid sample. The process for determining the size of cell nuclei is discussed by analyzing measurements of basal cells in a sub-surface layer of intact, unstained epithelial tissue.

2003-12-01

23

Translocation of particles to the pleural space and tracheobronchial lymph nodes following lung deposition  

Energy Technology Data Exchange (ETDEWEB)

The translocation of particles from the alveolar compartment to the pleural space and tracheobronchial lymph nodes was investigated in rats over a 30 day period following the intrapulmonary instillation of 4 x 10/sup 8/ polystyrene microspheres (1.9 ..mu..m dia.). In initial studies, approx. =10/sup 4/ particles were found in the pleural space compartment on Days 1, 14 and 30 after particle deposition, and most of these were cell-associated. Subsequent pleural space studies indicated, however, that the particles found in this compartment were, at least in part, due to the pleural lavage technique, and, unlike observations reported for some fibers, the translocation of the particles used in our study to the pleural space does not represent an important lung clearance pathway. In regard to particle clearance to the tracheobronchial lymph nodes, the accumulation of particles, most of which were extracellular, kinetically was biphasic with the most rapid phase ...

1985-01-01

24

Monte Carlo simulations incorporating Mie calculations of light transport in tissue phantoms: Examination of photon sampling volumes for endoscopically compatible fiber optic probes  

Energy Technology Data Exchange (ETDEWEB)

Details of the interaction of photons with tissue phantoms are elucidated using Monte Carlo simulations. In particular, photon sampling volumes and photon pathlengths are determined for a variety of scattering and absorption parameters. The Monte Carlo simulations are specifically designed to model light delivery and collection geometries relevant to clinical applications of optical biopsy techniques. The Monte Carlo simulations assume that light is delivered and collected by two, nearly-adjacent optical fibers and take into account the numerical aperture of the fibers as well as reflectance and refraction at interfaces between different media. To determine the validity of the Monte Carlo simulations for modeling the interactions between the photons and the tissue phantom in these geometries, the simulations were compared to measurements of aqueous suspensions of polystyrene microspheres in the wavelength range 450-750 nm.

1996-04-01

25

Dialysis membrane for separation on microchips  

Energy Technology Data Exchange (ETDEWEB)

Laser-induced phase-separation polymerization of a porous acrylate polymer is used for in-situ fabrication of dialysis membranes inside glass microchannels. A shaped 355 nm laser beam is used to produce a porous polymer membrane with a thickness of about 15 .mu.m, which bonds to the glass microchannel and forms a semi-permeable membrane. Differential permeation through a membrane formed with pentaerythritol triacrylate was observed and quantified by comparing the response of the membrane to fluorescein and fluorescently tagging 200 nm latex microspheres. Differential permeation was observed and quantified by comparing the response to rhodamine 560 and lactalbumin protein in a membrane formed with SPE-methylene bisacrylamide. The porous membranes illustrate the capability for the present technique to integrate sample cleanup into chip-based analysis systems.

2010-07-13

26

Design and development of an innovative hybrid powder based on a computer simulation and its application to foundation makeup products  

British Library Electronic Table of Contents (United Kingdom)

An innovative hybrid powder prepared using computer simulation allowed development of a new foundation having a fine, smooth texture that has never been achieved before. The optical structure/design of the powder was based on the results of measurements and analyses conducted on the optical characteristics of a baby's delicate skin, which is the envy of many women. To obtain the optimal optical characteristics, the finite differential time domain (FDTD) method for solving Maxwell's differential equation by difference and time domain was applied to the computer simulation method. For synthesis of the hybrid powder based on the optical model, a proprietary shape regulation coating technology was used in which flaky substrates were coated with microspherical forms of barium sulfate crystals. ...

2008-01-01

27

Alpha-particle dose distribution effects at the cellular level  

International Nuclear Information System (INIS)

Ionizing radiations that differ in number, size, and distribution of energy deposition events might be expected to cause different effects for the same absorbed dose. Furthermore, microdosimetry calculations suggest that large variations in biological effectiveness might be expected for internally deposited alpha-emitting radionuclides for the same absorbed dose, depending upon the specific activity and spatial distribution of the sources in tissue. The study described in this article was designed to demonstrate these phenomena in vitro. Cultured Chinese hamster ovary (CHO-K1 BH4) cells were exposed in vitro to inert, insoluble ceramic microspheres in zirconium dioxide labeled with "2"3"9Pu. The average exit energy of the 5.15 MeV alpha particle was calculated to be 4.3 MeV. Exposure times varied from four to seven hours to achieve the desired dose level.

1985-02-01

28

Intestinal circulation during inhalation anesthesia  

Energy Technology Data Exchange (ETDEWEB)

This study was designed to evaluate the influence of inhalational agents on the intestinal circulation in an isolated loop preparation. Sixty dogs were studied, using three intestinal segments from each dog. Selected intestinal segments were pumped with aortic blood at a constant pressure of 100 mmHg. A mixture of /sub 86/Rb and 9-microns spheres labeled with /sup 141/Ce was injected into the arterial cannula supplying the intestinal loop, while mesenteric venous blood was collected for activity counting. A very strong and significant correlation was found between rubidium clearance and microsphere entrapment (r = 0.97, P less than 0.0001). Nitrous oxide anesthesia was accompanied by a higher vascular resistance (VR), lower flow (F), rubidium clearance (Cl-Rb), and microspheres entrapment (Cl-Sph) than pentobarbital anesthesia, indicating that the vascular bed in the intestinal segment was constricted and flow (total and nutritive) decreased. ...

1985-04-01

29

Intestinal circulation during inhalation anesthesia  

International Nuclear Information System (INIS)

This study was designed to evaluate the influence of inhalational agents on the intestinal circulation in an isolated loop preparation. Sixty dogs were studied, using three intestinal segments from each dog. Selected intestinal segments were pumped with aortic blood at a constant pressure of 100 mmHg. A mixture of _8_6Rb and 9-microns spheres labeled with "1"4"1Ce was injected into the arterial cannula supplying the intestinal loop, while mesenteric venous blood was collected for activity counting. A very strong and significant correlation was found between rubidium clearance and microsphere entrapment (r = 0.97, P less than 0.0001). Nitrous oxide anesthesia was accompanied by a higher vascular resistance (VR), lower flow (F), rubidium clearance (Cl-Rb), and microspheres entrapment (Cl-Sph) than pentobarbital anesthesia, indicating that the vascular bed in the intestinal segment was constricted and flow (total and nutritive) decreased. ...

30

Technetium-99m dithiocarbamates as potential agents for brain imaging  

International Nuclear Information System (INIS)

Thallium-201 diethyldithiocarbamate (DDC) behaves like a chemical microsphere and is trapped by spontaneous decomposition in the brain in proportion to regional perfusion. They have shown that the technetium-99m analog, Tc-99m DDC (1), is unsuitable for cerebral perfusion imaging because it does not decompose rapidly enough to be trapped in the brain. With the goal of turning this greater stability of 1 into an advantage, a series of dithiocarbamates with lipophilic or amine groups designed to enhance cerebral uptake and retention was prepared from the following amines by reaction with carbon disulfide and sodium hydroxide: pyrrolidine (2), piperazine (3), 4-benzylpiperazine (4), and 4-(1-piperidino)piperidine (5). These ligands (5 mg) were labelled with Tc-99m in > 95% efficiency (ITLC-SG, saline) by reduction of pertechnetate at room temperature with formamidine sulfinic acid at alkaline pH. In preliminary studies, 4 and 5 show a trend of increasing oil/buffer ...

31

Hemodynamic characterization of chronic bile duct-ligated rats: effect of pentobarbital sodium  

International Nuclear Information System (INIS)

Systemic and splanchnic hemodynamics of the chronic bile duct-ligated rat were characterized by radioactive microspheres. Conscious and pentobarbital sodium-anesthetized, bile duct-ligated and sham-operated rats had cardiac output and regional organ blood flows determined. The conscious bile duct-ligated rat compared with the sham-operated showed a hyperdynamic circulation with an increased cardiac output and portal tributary blood flow. Pentobarbital sodium anesthesia induced marked hemodynamic changes in both sham-operated and bile duct-ligated rats. The latter group was especially sensitive to its effects; thus, comparison of cardiac output and portal tributary blood flow between anesthetized bile duct-ligated and sham-operated rats showed no significant differences. The authors conclude that the rat with cirrhosis due to chronic bile duct ligation is an excellent model for hemodynamic investigations but should be studied in the conscious state, since ...

32

Estimation of parameters affecting the uptake of sup(99m)Tc-methylenediphosphonate in rat femur with model simulation  

Energy Technology Data Exchange (ETDEWEB)

The uptake of sup(99m)Tc-methylenediphosphonate (MDP) in different parts of rat femur was simulated using a local three-space model for tracer transfer. The model consisted of bone blood, bone ECF-space and space for tracer deposition. The measured sup(99m)Tc-MDP concentration in the systemic blood and the local bone blood flow measured by /sup 131/I-macroaggregated albumin microspheres were used as input parameters. The measured blood flow values were 6.3, 3.1 and 15.3 ml/100 g/min for proximal, middle and distal femur, respectively. the model parameters that gave the best fit to measured sup(99m)Tc-MDP uptake curves in computer simulation showed that bone blood flow, volume of ECF-space, permeability surface area product and accretion constant from ECF-space to space for tracer deposition were highest in distal and lowest in middle femur. The values corresponded to peak extraction fractions of 0.38, 0.62, and 0.31 for proximal, middle and distal femur, ...

1985-01-01

33

Estimation of parameters affecting the uptake of sup(99m)Tc-methylenediphosphonate in rat femur with model simulation  

International Nuclear Information System (INIS)

The uptake of sup(99m)Tc-methylenediphosphonate (MDP) in different parts of rat femur was simulated using a local three-space model for tracer transfer. The model consisted of bone blood, bone ECF-space and space for tracer deposition. The measured sup(99m)Tc-MDP concentration in the systemic blood and the local bone blood flow measured by "1"3"1I-macroaggregated albumin microspheres were used as input parameters. The measured blood flow values were 6.3, 3.1 and 15.3 ml/100 g/min for proximal, middle and distal femur, respectively. the model parameters that gave the best fit to measured sup(99m)Tc-MDP uptake curves in computer simulation showed that bone blood flow, volume of ECF-space, permeability surface area product and accretion constant from ECF-space to space for tracer deposition were highest in distal and lowest in middle femur. The values corresponded to peak extraction fractions of 0.38, 0.62, and 0.31 for proximal, middle and distal femur, respectively. ...

34

Development and field application of a leak sealant for the NRU water reflector  

International Nuclear Information System (INIS)

The development and successful application of a unique leak sealant formulation comprised of a mixture of graded, hollow ceramic microspheres, surface oxidized aluminum powder and saturated gibbsite suspension is described. The project was undertaken to address the escalating leakage from up to 15 small weld defects in the water reflector vessel, an integral component of the NRU (National Research Universal) reactor calandria. The reflector surrounds the reactor core with a neutron reflecting blanket of light water. Injection of the sealant is typically done with the reactor shutdown and the water reflector system operating normally, but can also be performed with the reactor at full power. The procedure is simple and effective. Individual treatments of as little as 125 ml of sealant (10 ppm in the 12,500 L system) have yielded leak reductions exceeding 2000 L/day. The accumulated leak reductions of several treatments now total 90% of the historic high of 5,400 ...

2001-06-10

35

Criticality calculations of the fixed bed nuclear reactor  

Energy Technology Data Exchange (ETDEWEB)

The Fixed Bed Nuclear Reactor (FBNR) is a small 40 MWe reactor based on the Pressurized Water Reactor (PWR) technology. FBNR is an integrated primary circuit and simple in design. It has the characteristics of being small, modular, proliferation resistant, inherently safe and passively cooled reactor with reduced adverse environmental impact. It utilizes the fuel designed for high temperature reactors operating in a relatively low temperature of PWR environment The 15 mm diameter spherical fuel elements are made of TRISO type microspheres embedded in graphite and cladded by SiC. The coolant flow transfers them from the fuel chamber into the core and become fixed forming a suspended core. Any accident signal will cut off the power to the coolant pump causing a stop in the flow. This results in making the fuel elements fall out of the reactor core by the force of gravity and return into the fuel chamber where they are passively cooled under subcritical condition. ...

2007-07-01

36

Chemoembolization (TACE) of Unresectable Intrahepatic Cholangiocarcinoma with Slow-Release Doxorubicin-Eluting Beads: Preliminary Results  

International Nuclear Information System (INIS)

The purpose of this study was to evaluate the safety and efficacy of TACE with microspheres preloaded with doxorubicin in unresectable intrahepatic cholangiocarcinoma (UCH). Twenty patients with UCH were observed; 9 refused, preferring other palliative care or chemotherapy, and 11 agreed to be treated with one or more cycles of DC beads loaded with doxorubicin (100-150 mg) in a TACE procedure between February 2006 and September 2007. A total of 29 individual TACE procedures were performed. Follow-up imaging was performed on all patients before, immediately after, and 4 weeks after each TACE procedure to evaluate the response and need for further treatment. Each patient received i.v hydration, antibiotics, and medications against nausea and pain before TACE. Survival rate was calculated using Kaplan-Meier survival curve. A response rate of 100% followed RECIST criteria was observed. Eight of eleven patients are alive, with a median survival of 13 months. TACE was ...

2008-09-01

37

A novel micro-spherical CoSn{sub 2}/Sn alloy composite as high capacity anode materials for Li-ion rechargeable batteries  

Energy Technology Data Exchange (ETDEWEB)

Micro-scaled spherical CoSn{sub 2}/Sn alloy powders synthesized from oxides of Sn and Co via carbothermal reduction at 800 C were examined for use as anode materials in Li-ion battery. The phase composition and particle morphology of the CoSn{sub 2}/Sn alloy composite powders were investigated by XRD, SEM and TEM. The prepared CoSn{sub 2}/Sn alloy composite electrode exhibits a low initial irreversible capacity of ca. 140 mAh g{sup -1}, a high specific capacity of ca. 600 mAh g{sup -1} at constant current density of 50 mA g{sup -1}, and a good rate capability. The stable discharge capacities of 500-515 mAh g{sup -1} and the columbic efficiencies of 95.8-98.1% were obtained at current density of 500 mA g{sup -1}. The relatively large particle size of CoSn{sub 2}/Sn alloy composite powder is apparently favorable for the lowering of initial capacity loss of electrode, while the loose particle structural characteristic and the Co addition in Sn matrix should be responsible for the ...

2007-04-01

38

Nephron-sparing percutaneous ablation of a 5 cm renal cell carcinoma by superselective embolization and percutaneous RF-ablation  

Energy Technology Data Exchange (ETDEWEB)

Purpose: To report on the nephron-sparing, percutaneous ablation of a large renal cell carcinoma by combined superselective embolization and percutaneous radiofrequency ablation. Materials and Methods: A 5 cm renal cell carcinoma of a 43-year-old drug abusing male with serologically proven HIV, hepatitis B and C infection, who refused surgery, was superselectively embolized using microspheres (size: 500 - 700 {mu}m) and a platinum coil under local anesthesia. Percutaneous radiofrequency ablation using a 7F LeVeen probe (size of expanded probe tip: 40 mm) and a 200 Watt generator was performed one day after transcatheter embolization under general anesthesia. Results: The combined treatment resulted in complete destruction of the tumor without relevant damage of the surrounding healthy renal tissue. The patient was discharged 24 hours after RF ablation. No complications like urinary leaks or fistulas were observed and follow up CT one day and 4 weeks after the ...

2001-11-01