[en] Short communication

[en] Short communication

[en] This paper considers hydrogen storage in nano-porous carbons, either under di-hydrogen pressure or by cathodic electro-decomposition of water. Di-hydrogen adsorption in the nano-pores of porous carbons is only significant when decreasing temperature to 77 K. An optimum pore size ca. 0.6 nm has been predicted theoretically and experimentally confirmed, which corresponds to two layers of hydrogen adsorbed in the pores. By contrast, in the case of the electrochemical technique, noticeable sorption of hydrogen is observed in ambient conditions. The various experimental data, especially the dependence of cyclic voltammetry and galvano-static characteristics with temperature, demonstrate that hydrogen electrochemically trapped in nano-porous carbons is not purely physi-sorbed, and that it exhibits a partially chemical bonding. This process represents an important breakthrough for hydrogen storage in carbon materials and is able to find quick applications for a new generation of power sources in aqueous medium. (authors)

[en] Radioactively labeled peptides are powerful tools for an individualized, patient based treatment of oncological diseases. The excellent targeting concomittant with the easy radiolabeling enable such fully synthetic molecules for patient selection (diagnosis) and internal irradiation (therapy). Peptides labeled with radiohalogenes as well as radiometals were used successfully for the diagnosis and therapy of numerous malignancies. The use of ⁹⁰Y-DOTATOC and ¹⁷⁷Lu-DOTATATE for the treatment of patients with neuroendocrine tumors, refrectory to chemotherapy, underline the potential of radiopeptides. ^99mTc-NeoTect registered, another somatostatin targeting peptide-radiometal conjugate, detects lung lesions with 97% sensitivity and > 70% specificity employing SPECT. Pre-clinical results of ¹⁸⁸Re-NeoTide registered, the radiotherapeutic counterpart of ^99mTc-NeoTect registered, indicate significant tumor regression in lung tumor models. The α_vβ₃-targeted detection of neoangiogenesis proves radiopeptides to be valuable tools for the diagnostic imaging of multiple tumor entities, since α_vβ₃-receptors are overexpressed in a variety of tumors undergoing new blood-vessel formation. The application of (¹⁸F)-Galacto-RGD, a high-affinity binder for α_vβ₃-receptors, pinpoints the potential of peptides for tumor detection (Fig. 5) and staging. The successful use of ^99mTc-Demogastrin registered for detection of medullary thyroid carcinoma and its multiple metastases opens a new field in diagnosis and therapy of solid tumors. (orig.)

[en] An efficient method of hydrogen storage in nano-porous carbons is its reversible sorption by electrochemical decomposition of a KOH water solution [1-3] according to the following equation: C + xH₂O + xe^- → (CH_x) + xOH^- where (CH_x) stands for the hydrogen inserted into the nano-porous carbon during charging and oxidized during discharging. Although various carbon materials have been investigated as hydrogen adsorbents, the information about the storage mechanism as well as the nature of the hydrogen/carbon interaction is still not sufficient. In order to extend the understanding of the process, carbon samples charged electrochemically were investigated by temperature programmed desorption (TPD). The nature of the hydrogen/carbon interaction was studied by electrochemical analysis at different temperatures. The TPD experiments consist of heating the samples from room temperature to 950 C and of quantitative analysis by on-line mass spectrometry, the di-hydrogen evolved from the carbon material. Fig 1 shows the desorption rate of hydrogen during the TPD experiment carried out on an activated carbon cloth loaded at -500 mA/g during 12 hours. The first peak below 300 C corresponds to the desorption of hydrogen fixed on the carbon surface during the charging process. The shape and the position of this peak suggests that this gas is released from sites of different and relatively high energies. The second hydrogen peak results from the reaction between the carbon material and KOH as already mentioned in literature [4]. Carbon materials were also loaded at -500 mA/g during different times (3, 6, 12 and 24 hours), and then analysed by TPD, showing that the intensity of the peak below 300 C increases with the charging time. Hence TPD gives the direct proof that hydrogen is really stored in nano-porous carbons by this electrochemical process. Moreover, the position of the desorption peaks demonstrates that at least a part of hydrogen presents stronger interactions than in the state of physisorption. In order to confirm the latter interpretation, galvano-static cycling and cyclic voltammetry experiments were realized in 6 mol.L^-1' KOH at various temperatures ranging from 20 to 60 C. The results obtained show that, as temperature increases, both cathodic and anodic processes are accelerated (Fig. 2) by reducing the kinetic barriers, and in consequence the hydrogen uptake efficiency is enhanced. On the basis of the electrochemical data, an Arrhenius plot was created, and the activation energy related to the hydrogen reaction was estimated. [1] K. Jurewicz, E. Frackowiak, F. Beguin, Electrochem Solid State Lett, 4, A27, 2001; [2] K. Jurewicz, E. Frackowiak, F. Beguin, Appl Phys A, 78, 981, 2004; [3] C. Vix-Guterl, E. Frackowiak, K. Jurewicz, M. Friebe, J. Parmentier, F. Beguin, Carbon, 43, 1293, 2005; [4] M.A. Lillo-Rodenas, J. Juan-Juan, D. Cazorla-Amoros, A. Linares-Solano, Carbon, 42, 1365, 2004. (authors)

[en] Reduction of perrhenate with stannous chloride at an excess of sodium gluconate in aqueous solution results in formation of rhenium(V) gluconate. The reaction proceeds slowly compared to that of pertechnetate. Aqueous solutions of rhenium(V) gluconate can be prepared down to a concentration level of at least 10 4 mol·^-1 within two hours. The usefulness of rhenium(V) gluconate to serve as a precursor for preparation of oxorhenium(V) complexes as potential radio therapeutic agents is revealed by subsequent ligand exchange reactions carried out with mercaptoacetyldiglycine, 3-thiapentane-dithiol-1,5/butanethiol and with 2-aminobenzenethiol. 5 figs., 14 refs

[en] Purpose: In this study we assessed the effect of an interactive breath-hold control system on procedure time and technical success in transthoracic CT-guided lung biopsies. Materials and Methods: in 36 patients (4 female, 32 male, mean age 65 years; range 33 - 88) with a pulmonary nodule, we performed CT-guided biopsy using a 18G Tru-cut needle (Cardinal Health, Dublin, UK) in a 64 row dual-source CT scanner (Somatom Definition, Siemens, Forchheim, Germany) using intermittent imaging of the needle. In half of the patients (2 female, 16 male, mean age 67 years), an interactive breathhold control system (IBC) (Mayo Clinic Medical Devices, USA) was applied. No additional device was used in the control group. Results: the biopsy was visually successful in all patients. The diameter of the target lesion was comparable in both groups (IBC: 30 ± 19 mm; control: 28 ± 15 mm). The number of imaging steps was significantly smaller (p < 0.05) and the intervention time was significantly shorter (p < 0.05) in the IBC group (IBC: 9 ± 5 steps 17 ± 10 min; control: 13 ± 5 steps 26 ± 12 min). Conclusion: application of the IBC unit reduced the intervention time and radiation exposure in CT-guided Tru-cut biopsy of pulmonary nodules. (orig.)

[en] A series of systematically altered neutral oxorhenium complexes of the general formula ReO[Et₂NCH₂CH₂N(CH₂CH₂S)₂][p-X-C₆H₄-S] where X=NH₂ (1), OMe (2), Me (3), t-Bu (4), H (5), Cl (6), Br (7), I (8), NO₂ (9) was prepared by simultaneous action of (CH₃CH₂)₂NCH₂CH₂N(CH₂CH₂SH)₂ and p-XC₆H₄SH on [ReOCl₃(PPh₃)₂]. The molecular structure of complex 6 (where X=Cl) was determined by X-ray crystallography, revealing a trigonal bipyramidal geometry. P_HPLC/pH profiles and pK_a values were determined by HPLC