[en] Highlights: • A new method of Direct Friction Stir Processing is proposed to fabricate Mg/SiCp surface composite like a planter. • The tool was designed as a hollow and pinless tool, and the reinforcement were preplaced. • The reinforcement particles were homogeneous and dispersed in the stir zone. • The micro-hardness and wear property were promoted by refinement crystallization and reinforcement particles. - Abstract: In this paper, Direct Friction Stir Processing (DFSP) to produce surface composite was proposed. A hollow and pinless DFSP tool was designed to fabricate the surface composite on the AZ31 plate of rolling state. The reinforcement particles flowed out through the through-hole of DFSP tool and entered the enclosed space between shoulder and base metal. They were then pressed into the workpiece as the rotating tool advanced along it just like a ‘planter’. Microstructure observed by optical microscope and scanning electron microscope showed that the reinforcement particles were homogeneous and dispersed in the stir zone. The thickness of the composite layer reached 150 μm. The grain size decreased from 16.57 μm to 1.24 μm in the composite layer. The micro-hardness increased from 57.77 Hv to 115.51 Hv. The plow width of the AZ31 with SiC decreased from 620 μm to 410 μm for the wear test

[en] The absorption behavior of ⁶⁸Ga(III) and ⁶⁸Ge(IV) on three different type of ferric oxides has been studied. Alpha-ferric oxide in trigonal structure is found to be a suitable material for the generator. The elution yield of ⁶⁸Ga from the column of trigonal crystal of α-ferric oxide with absorbed ⁶⁸Ge(IV) can reach 90% in 1 ml 0.05 mol/l HCl solution, while the breakthrough of ⁶⁸Ge was less than 1.8 x 10^-4. This generator is stable and resistant to chemicals and radiation. The content of Fe in 1 ml eluate is less than 0.1 ppm. The recovery of ⁶⁸Ga was higher and more constant than that of the known ⁶⁸Ge-⁶⁸Ga generator system. (author)

[en] Preparation method of ¹²⁵I seeds was studied. It was found that silver was a good carrier body for ¹²⁵I and the ion-exchange technique was simple and effective for the preparation. Carrier iodine was critical for dose uniformity of the seeds and the minimal pH value for the reaction was 6.5. Valuable data for the development and preparation of ¹²⁵I seed is provided. (author)

[en] A method for ¹⁰³Pd 'molecular plating' onto the surface of the copper rod is reported. The optimal composition of the plating bath was: palladium chloride 2 g/l, ammonium hydroxide (28%) 150 ml/l, sodium hypophosphite 12 g/l, and ammonium chloride 37 g/l. The whole procedure of ¹⁰³Pd 'molecular plating' will last 50 minutes at 40 deg C. Valuable experience for the preparation of ¹⁰³Pd seeds is provided. (author)

[en] Objective: To update the clinical and experimental evaluation of the effects of radioactive stents on the prevention of intimal proliferation. Methods: The stents were bombarded with suitably charged particles of adapted energy in the cyclotron to create a proper mixture of the radionuclides, ⁵⁹Fe, ⁶⁰Co, ⁵⁸Co, ⁵⁷Co, ⁵¹Cr and ⁵⁴Mn in them. The radioactive stents were implanted unilaterally in rabbit iliac arteries; and at the same time, non-radioactive stents were implanted in the contralateral iliac arteries of the same rabbits serving as controls. The effects of radioactive stents on prevention of restenosis were assessed by angiography, histo-morphometry and immunocytochemistry, Results: All the iliac arteries that had been implanted radioactive stents were clear on angiography and had no radiation complication during the 1-2 month follow-up. There was significant reduction in neo-intimal area [(0.37 +- 0.14) mm² vs. (0.81 +- 0.10) mm², P < 0.01], percent area stenosis [(6.70 +- 2.91)% vs. (13.15 +- 1.40)%, P < 0.01] and PCNA immunoreactive rate [(2.00 +- 1.58)% vs. (10.88 +- 6.98)%, P < 0.05] in the radioactive stents group compared with that in the control stents group. Conclusions: Radioactive stents with an activity of 33.819 - 61.189 kBq could inhibit the intimal proliferation in the animal model. The radioactive stents implantation is feasible for prevention of intimal proliferation

[en] ¹⁸F-labeled amino acid O-(2-[¹⁸F]fluoroethyl)-L-tyrosine ([¹⁸F]FET) has been used as an in vivo positron emission tomography (PET) tracer for tumor metabolitic imaging. Here, the synthesis of [¹⁸F]FET using two different methods is reported. The first Method (I) for the [¹⁸F]FET synthesis was an indirect labeling route, which was a two-step reaction consisting of fluorination of 1,2-bis(tosyloxy)ethane and fluoroalkylation of unprotected L-tyrosine. The second Method (II) was a direct labeling route which was the direct nucleophilic radiofluorination of the protected precursor N-BOC-(O-(2-tosyloxyethyl))-L-tyrosine methyl ester, followed by a rapid removal of the protecting group. For the first method, the radiochemical yield was about 45% at the end of synthesis (EOS), and the radiochemical purity was over 97%. The radiochemical yield in the second method was 40% (EOS) on an average, and the radiochemical purity was over 96%. Microwave heating was also introduced into the synthesis of [¹⁸F]FET. For Method I, each of two steps could be completed within 2-3 minutes under microwave conditions and the radiochemical yields were 85% and 95%, respectively, which was reasonably high and reproducible. For Method II, the highest labeling efficiency in the radiofluorinated step was 37% in the synthesis time of 3 minutes under microwave conditions. (author)

[en] Ultrafine well-dispersed magnetite nanoparticles were directly prepared in aqueous solution using the controlled coprecipitation method. This paper discusses the preparation of novel surface silica modified colloids with a core of single-domain magnetite particles. Amino-silane was covalently coupled to the colloids and activated by glutaraldehyde. The underlying idea is to tailor the silica shell thickness and surface properties such that the colloids became stable spheres with isotropic interactions, whereas an external magnetic field produces weak dipolar attractions and consequently reversible anisotropic structures. Hepama-1, a humanized monoclonal antibody directed against liver cancer, was coated on functional magnetic nanoparticles by the cross-linker glutaraldehyde to prepare immuno-magnetic nanoparticles (IMN). A direct labeling method was adopted to radiolabel IMN with ¹⁸⁸Re. The radiolabeling efficiency was about 90% with good in vitro stability. Such nanoparticles might be useful for bio-magnetic radiotherapy. (author)

[en] Fac-[¹⁸⁸Re(CO)₃(H₂O)₃]⁺ was synthesized with an overall radiochemical yield of 80±5%, and more than 95% radiochemical purity after a QMA Sep-Pak column separation. Fac-[Re(CO)₃(H₂O)₃]⁺ was also synthesized as a reference sample. The structure of the precursor, fac-[¹⁸⁸Re(CO)₃(H₂O)₃]⁺, was confirmed by high performance of liquid chromatography (HPLC). MN-His (magnetic nanoparticles coated with silica and modified with an amino silane coupling agent, N-[3-(trimethyoxysilyl)propyl]-ethylenediamine (SG-Si900) and immobilized with histidine) was labeled with fac-[¹⁸⁸Re(CO)₃(H₂O)₃]⁺ and an initial animal test of MN-His was conducted for a magnetic targeting study. (author)

[en] The dopamine D₄ receptor (D₄R) is expressed in low density in various extrastriatal brain regions. This receptor subtype is discussed in relation to the pathophysiology and treatment of schizophrenia but to date no selective positron emission tomography (PET) ligand is available to study its distribution in vivo. The 7-azaindole derivative 3-([4-(4-iodophenyl)piperazin-1-yl]-methyl)-1H-pyrrolo [2,3-b]pyridine (L-750,667) is a novel, high-affinity (K_i=0.51nM) and selective D₄R ligand. L-750,667 analogue 3-[4-(4-[¹⁸F]fluorobenzyl)]piperazin-1-yl methyl-1H-pyrrolo[2,3-b]-pyridine was prepared by reacting 3-(piperazin-1-yl)-methyl-1H-pyrrolo[2,3-b]pyridine with 4-[ 18F]fluorobenzaldehyde, which was labeled with no carrier added [ 18F]fluoride. The radiochemical yield of 3-[4-(4-[¹⁸F]fluorobenzyl)]piperazin-1-yl methyl-1H-pyrrolo[2,3-b]pyridine was 12.0% at end of synthesis (EOS), and the synthesis time was 73min. The labeled benzaldehydes may be useful precursors for the radiosyntheses of other complex radiotracers for PET

[en] Two different dispersion methods were studied in order to obtain rhenium [¹⁸⁸Re] sulfide suspension with different particle size distributions. The manufactured swirling device offers Suspension I with larger particles (55% > 5 μm, 19% > 10 μm). However, ultrasonication can only produce Suspension II with smaller particles (93% < 5 μm, 0.3% > 10 μm). Stability tests indicated that deposition appears after 6 and 15 minutes for Suspensions I and II, respectively. Radiochemical purity and particle size distribution did not change distinctively within 24 hours. So, both suspensions can be used in animal tests to find out the optimal particle size ranges for intra-articular injection. (author)