H. Afarideh

In vivo SPECT imaging of tumors by 198,199Au-labeled graphene oxide nanostructures

Graphene oxide (GO) sheets functionalized by aminopropylsilyl groups (8.0 wt.%) were labeled by (198,199)Au nanoparticle radioisotopes (obtained through reduction of HAuCl4 in sodium citrate solution followed by thermal neutron irradiation) for fast in vivo targeting and SPECT imaging (high purity germanium-spectrometry) of tumors. Using instant thin layer chromatography method, the physicochemical properties of the amino-functionalized GO sheets labeled by (198,199)Au NPs ((198,199)Au@AF-GO) were found to be highly stable enough in organic phases, e.g. a human serum, to be reliably used in bioapplications. In vivo biodistribution of the (198,199)Au@AF-GO composite was investigated in rats bearing fibrosarcoma tumor after various post-injection periods of time. The (198,199)Au@AF-GO nanostructure exhibited a rapid as well as high tumor uptake (with uptake ratio of tumor to muscle of 167 after 4h intravenous injection) that resulted in an efficient tumor targeting/imaging. Meantime, the low lipophilicity of the (198,199)Au@AF-GO caused to its fast excretion (~24 h) throughout the body by the kidneys (as also confirmed by the urinary tract). Because of the short half-life of (198,199)Au radioisotopes, the (198,199)Au@AF-GO with an excellent tumor targeting/imaging and fast washing out from the body can be suggested as one of the most effective and promising nanomaterials in nanotechnology-based cancer diagnosis and therapy.

Synthesis, characterization and theranostic evaluation of Indium-111 labeled multifunctional superparamagnetic iron oxide nanoparticles.

Indium-111 labeled, Trastuzumab-Doxorubicin Conjugated, and APTES-PEG coated magnetic nanoparticles were designed for tumor targeting, drug delivery, controlled drug release, and dual-modal tumor imaging. Superparamagnetic iron oxide nanoparticles (SPIONs) were synthesized by thermal decomposition method to obtain narrow size particles. To increase SPIONs circulation time in blood and decrease its cytotoxicity in healthy tissues, SPIONs surface was modified with 3-Aminopropyltriethoxy Silane (APTES) and then were functionalized with N-Hydroxysuccinimide (NHS) ester of Polyethylene Glycol Maleimide (NHS-PEG-Mal) to conjugate with thiolated 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-3,6,9,-triacetic acid (PCTA) bifunctional chelator (BFC) and Trastuzumab antibody. In order to tumor SPECT/MR imaging, SPIONs were labeled with Indium-111 (T1/2=2.80d). NHS ester of monoethyl malonate (MEM-NHS) was used for conjugation of Doxorubicin (DOX) chemotherapeutic agent onto SPIONs surface. Mono-Ethyl Malonate allows DOX molecules to be attached to SPIONs via pH-sensitive hydrazone bonds which lead to controlled drug release in tumor region. Active and passive tumor targeting were achieved through incorporated anti-HER2 (Trastuzumab) antibody and EPR effect of solid tumors for nanoparticles respectively. In addition to in vitro assessments of modified SPIONs in SKBR3 cell lines, their theranostic effects were evaluated in HER2 + breast tumor bearing BALB/c mice via biodistribution study, dual-modal molecular imaging and tumor diameter measurements.

New ellipsoid cavity model for high-intensity laser–plasma interaction

In this work we present an ellipsoid cavity regime for the production of a bunch of quasi-monoenergetic electrons. The electron output beam is more effective than the periodic plasma wave method or the plasma-channel-guided method. A hyperbola, parabola or ellipsoid path is described for the electron trajectory motion in this model. A dense bunch of relativistic electrons with a quasi-monoenergetic spectrum is self-generated here. The obtained results show a smaller width for the electron energy spectrum in comparison with the previous results. We found that there are optimum conditions to form the ellipsoid cavity. Laser beam properties (such as the spot size, power and pulse duration) and plasma features can control the ellipsoid cavity formation. The optimum conditions for effective electron beam production can be determined from these results.

Investigation of beam uniformity in industrial electron accelerator

Abstract In this paper the performances of the industrial electron beams processing, with 5 and 10 MeV energies, has been investigated by measuring two-dimensional dose distribution in electron beam profile. Large volume of absorbing materials with densities 0.5 and 1 g / cm 3 , which are wood and polyethylene, respectively, are used as the irradiated materials. On the other hand the mentioned measurement are also performed for X-ray (Bremsstrahlung) beam that were converted by interaction of electron with a high power X-ray target. The experiments have been performed using several types of film dosimeters such as PVB, CTA and FWT. These dosimeters are used for beam profile measurement and precise dose evaluation. The obtained results clearly show that the electron beam emerging out from scanning horn has a good uniformity along the electron beam profile.

L subshell and total M shell x-ray production cross sections of Hg for protons of energy 0.7 - 2.9 MeV

X-ray production cross sections of individual L lines, L and M total of Hg were measured for 0.7 to 2.9 MeV protons. The experimental results were compared with the theoretical predictions of the plane wave Born approximation (PWBA), ECPSSR and the semi-empirical formula of Orlic. Good agreements were obtained for L1 at lower energies and L2 and L3 at higher energies with Orlic and ECPSSR predictions, respectively. The influence of using different databases for x-ray fluorescence yields and Coster - Kronig transition probabilities is also discussed. The results of this work were not compared to any other reported data, since no experimental cross sections for mercury were found in the literature.

Determination of toxic and non-toxic hair trace elements in tobacco smokers using PIXE and NAA techniques

Abstract Particle-Induced X-ray Emission (PIXE) and Neutron Activation Analysis (NAA) were used to determine head hair trace elements with some emphasis on cadmium as a very toxic element. Samples were collected from smoker farmers of a village living far from industrial centres. The results were compared with a data set from non-smoker residents of the same village. The measured values point to the idea that as a result of Cd contamination in “case” samples the amounts of Zn and Se decreased with respect to control samples.

Electron heating enhancement by frequency-chirped laser pulses

Propagation of a chirped laser pulse with a circular polarization through an uprising plasma density profile is studied by using 1D-3V particle-in-cell simulation. The laser penetration depth is increased in an overdense plasma compared to an unchirped pulse. The induced transparency due to the laser frequency chirp results in an enhanced heating of hot electrons as well as increased maximum longitudinal electrostatic field at the back side of the solid target, which is very essential in target normal sheath acceleration regime of proton acceleration. For an applied chirp parameter between 0.008 and 0.01, the maximum amount of the electrostatic field is improved by a factor of 2. Furthermore, it is noticed that for a chirped laser pulse with a0 = 5, because of increasing the plasma transparency length, the laser pulse can penetrate up to about ne ≈ 6nc, where nc is plasma critical density. It shows 63% increase in the effective critical density compared to the relativistic induced transparency regime for ...

A NEURO-FUZZY BASED MODEL FOR ACCURATE ESTIMATION OF THE LYAPUNOV EXPONENTS OF AN UNKNOWN DYNAMICAL SYSTEM

A neuro-fuzzy based model is proposed in this paper for estimating the Lyapunov exponents of an unknown dynamical system according solely to a set of observations. Several approaches have been presented in recent years; most of them using the approximation of both the function of the trajectory of observations and the partial derivatives, to yield the Jacobian matrix of the function. The Jacobian matrix is then employed in the Jacobian-based methods that extract the Lyapunov exponents by QR-decomposition. While the accurate estimation of Lyapunov exponents has been sought, most of the related papers mainly focus on the accuracy of the trajectory approximation. In this paper, an Adaptive Neuro-Fuzzy Inference System is presented and stated to be an efficient tool for such a purpose. Structural parameters of the proposed model as the embedding dimension and the delay time are calculated by the Takens theorem and autocorrelation function, respectively. Model validation is performed by cross approximate entropy. Then, the promising performance of the proposed model as an accurate estimation of the Lyapunov exponents and its robustness to the measurement noise are finally evaluated.

Design, calibration and testing of the NRCAM fast neutron spectrometry system

Abstract This paper describes the design, calibration and testing of all aspects of an NE-213 detection system which was built for measuring neutron spectra from 1 to 30 MeV . To cover the whole energy range two detectors are required. A smaller detector is usually used for the lower energy range, but for the upper energy limit, in which we are interested, a larger detector is needed. Particular attention has been paid to cell construction and reflective paint covering. Decisions on the length of light guide which leads to optimum resolution have been made on the basis of experiment and Monte Carlo simulation of the photon transport within the cell and light guide, previously reported. Response matrix information for the detector has been prepared with the codes 05S (A Monte-Carlo code for calculating the pulse-height distributions due to monoenergetic neutrons on organic scintillators. Oak Ridge National Laboratory ORNL-4160) and SCINFUL (SCINFUL: a Monte Carlo based computer program to determine a scintillator full energy response to neutron detection for En between 0.1 and 80 MeV : program development and comparisons of program predictions with experimental data. Oak Ridge National Laboratory ORNL-6463), with validation at a few energy points against quasi-monoenergetic neutron sources available at the cyclotron of NRCAM. The unfolded spectra obtained by the detector when exposed to Americium–Beryllium, 15.2 and 28.2 MeV neutron fluences are shown as overall validation of the performance of the detector.

One-step, no-carrier-added, synthesis of a 18F-labelled benzodiazepine receptor ligand

5-(2-Phenoxy)phenyl-1,3,4-oxadiazole-2-yl-4-fluorobenzoate, a non-classical benzodiazepine receptor ligand, has shown anticonvulsant activity against pentylenetetrazole-induced convulsion. In order to perform biological studies, we decided to label the compound with positron-emitting fluorine-18 (t1/2=109.7 min). The latter compound was prepared in no-carrier-added form from [18F]fluoride and 5-(2-phenoxy)phenyl-1,3,4-oxadiazole-2-yl-4-N,N,N-trimethylanilinium triflate in one step. The best results were obtained using Kryptofix2.2.2/[18F]fluoride with dimethylsulfoxide as the solvent at 90°C. Column chromatography afforded the desired compound in 15 min in an overall radiochemical yield of 70–75% corrected to the end of radionuclide production with a specific radioactivity of about 3000 Ci/mmol and a radiochemical purity of more than 95% and high chemical purity. Copyright