Preparation and evaluation of Tc-99m hydroxyethyl starch as a potential radiopharmaceutical for lymphoscintigraphy: comparison with Tc-99m human serum albumin, Tc-99m dextran, and Tc-99m sulfur microcolloid

Tc-99m hydroxyethyl starch (Tc-99m HES) prepared with a labeling efficiency greater than 95% was evaluated in rabbits for visualization of lymphatic channels and lymph nodes, and the findings compared with Tc-99m human serum albumin (Tc-99m HSA), Tc-99m dextran (Tc-99m DXT), and Tc-99m sulfur microcolloid (Tc-99m SMC). Tc-99m HES showed good visualization of lymphatic channels and regional nodes and it had the highest clearance rate from the injection site (p less than 0.01). Tc-99m HES showed greater uptake by the nodes than Tc-99m DXT (p less than 0.001) at 90 minutes post-injection. The concentration of Tc-99m HES in the lymphatic channels was higher than that of Tc-99m SMC at 90 minutes post-injection (p less than 0.001). Preliminary clinical studies of Tc-99m HES yielded high quality lymphoscintigrams of the leg, and the pelvic and para-aortic lymph nodes in less than 10 minutes post-injection. In addition, partially and completed obstructed lymphatics could be differentiated from normal lymphatic pathways. In conclusion, Tc-99m HES is a promising radiopharmaceutical for imaging of lymphatic channels and nodes.     

Behavior of Silica Nanoparticles Synthesized from Rice Husk Ash by the Sol–Gel Method as a Photocatalytic and Antibacterial Agent

Silica nanoparticles (SiO₂ NPs) are one of the most well-studied inorganic nanoparticles for many applications. They offer the advantages of tunable size, biocompatibility, porous structure, and larger surface area. Thus, in this study, a high yield of SiO₂ NPs was produced via the chemical treatment of rice husk ash by the sol–gel method. Characteristics of the prepared SiO₂ NPs were validated using different characterization techniques. Accordingly, the phase, chemical composition, morphological, and spectroscopic properties of the prepared sample were studied. The average particle size of the SiO₂ NPs was found to be approximately 60–80 nm and the surface area was 78.52 m²/g. The prepared SiO₂ NPs were examined as photocatalysts for the degradation of methyl orange (MO) dye under UV irradiation. It was found that the intensity of the characteristic absorption band of MO decreased gradually with exposure time increasing, which means the successful photodegradation of MO by SiO₂ NPs. Moreover, the antibacterial activity of obtained SiO₂ NPs was investigated by counting the coliform bacteria in the surface water using the most probable number (MPN) index method. The results revealed that the MPN of coliform bacteria untreated and treated by SiO₂ NPs was estimated to be 170 CFU/100 mL and 10 CFU/100 mL, respectively, resulting in bacterial growth inhibition of 94.12%.     

Semantic monitoring of words with emotional connotation during fMRI: contribution of anterior left frontal cortex.

Previous studies showed that cortex in the anterior portions of the left frontal and temporal lobes participates in generating words with emotional connotations and processing pictures with emotional content. If these cortices process the semantic attribute of emotional connotation, they should be active whenever processing emotional connotation, without respect to modality of input or mode of output. Thus, we hypothesized that they would activate during monitoring of words with emotional connotations. Sixteen normal subjects performed semantic monitoring of words with emotional connotations, animal names, and implement names during fMRI. Cortex in the anterior left frontal lobe demonstrated significant activity for monitoring words with emotional connotations compared to monitoring tone sequences, animal names, or implement names. Together, the current and previous results implicate cortex in the anterior left frontal lobe in semantic processing of emotional connotation, consistent with connections of this cortex to paralimbic association areas. Current findings also indicate that neural substrates for processing emotional connotation are independent of substrates for processing the categories of living and nonliving things.     

Variational method for the distributed control of a vibrating beam

The problem of damping out the oscillations of a simply supported beam subject to viscous damping is solved analytically by employing a maximum principle. The basic control problem is to minimize the deflection and the velocity of displacements in a given period of time with the minimum possible expenditure of force. The multiobjective problem is scalarized by using a linear combination of the criteria. This problem is also solved by two heuristic approaches: a direct method and an integral equation approach.     

Gamma-Strahlensterilisation von Aerosoldruckpackungen mit Chlorfluorkohlenwasserstoffen als Treibgasen

Gamma Ray Sterilization of Pressurized Aerosol Packages Containing Chlorofluorohydrocarbons as Propellants Propellant stability during radiosterilization of aerosol packages was investigated to examine the suitability of ionizing radiation as a method of producing sterile aerosol preparations. The chlorofluorohydrocarbons Frigen 11 (CCl₃F) and 12 (CCl₂F₂) and their mixture 11/12 5050, purified by gaschromatography, were subjected to Co-60 radiation and examined for changes in chemical composition. No decomposition products were detected by gas chromatography or mass spectrometry.     

Boundary feedback control of a vibrating beam subject to a displacement constraint

The problem of controlling the dynamic response of a beam by means of boundary feedback is solved. The control is applied at one of the supports of the beam by means of a torque actuator in order to keep the maximum deflection within specified bounds. Since the location and time of the maximum deflection depend on the control itself, the feedback is determined by the solution of a min-max problem. The theory is illustrated by a numerical example involving an impulsively loaded beam, and the effectiveness of the proposed control is studied numerically.     

Radioaktive Markierung von Chlorfluorkohlenwasserstoffen durch Gamma-Strahlung

Radioactive Labelling of Chlorofluorohydrocarbons by Gamma Radiation Chlorofluorohydrocarbons were irradiated with high-energy gamma radiation in an electron linear accellerator. The (γ, n) reaction and the recoil of the hot ¹⁸F atoms led to the production of labelled compounds which could be used in pharmacokinetic investigations and as diagnostic agents for lung scintigraphy.