Publications

The synthesis of 3-cyclopentyl-1-adamantanamines and adamantanemethanamines and some of their thioureas is described. The antiviral activity examination of these compounds indicated that some of them inhibited Respiratory Syncytial Virus (RSV) infection at concentrations that were slightly (up to 5-fold) lower than the cytotoxic concentration. Behavioral and convulsions studies of the above mentioned amines, in mice, did not show any dopaminomimetic activity and argue in favor of the existence of a glutamatergic component in the action of these derivatives.

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CPT clocks are very attractive for their miniaturization potentiality. Nevertheless, two main effects limit today their performance: the optical pumping associated with circularly polarized lasers and the line broadening due to saturation effects. We propose to overcome these limitations by the use of orthogonal linear laser polarizations and a pulsed interrogation sequence. The optimization of the time sequence leading to the best characteristics (contrast, linewidth) of the dark resonance is discussed. Very preliminary measurements of the frequency stability demonstrate an interesting performance of 3.5 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-12</sup> tau <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-frac12</sub>

New reactions of methyl 2,2-difluoro glycosides are described that were utilized for synthesis of some novel nucleoside derivatives. Thus, treatment of methyl 2-deoxy-2,2-difluoro-3,4-O-isopropylidene-alpha (beta)-D-erythro-pyranoside (2) with anhydrous HCl resulted in selective displacement of one fluorine atom with chlorine to give a 2-deoxy-2-chloro-2-fluoro glycoside 3. Reaction of 3 with silylated uracil in the presence of SnCl4 provided a 2-deoxy-2-fluoro-2-uracil-substituted glycoside 4. 2-Fluoro-2-deoxy glycosides substituted with other pyrimidines at C-2 were prepared similarly by the reaction of acylated 2,2-difluoro or 2-fluoro-2-bromo derivatives (5 and 6, respectively) with silylated pyrimidines. The resulting 2'-fluorinated isonucleosides were evaluated for their antitumor and antiviral activities. Compounds 7a,b, 8a,b, and 10a,b demonstrated 50% tumor cell growth inhibition in vitro (IC50) at 10(-4)-10(-5) M. At similar concentrations no antiviral activity was observed in vitro. Therapeutic activity was obtained with 7a,b and 8a,b in DBA/2 mice with L1210 leukemia. Administration of 7a,b at 500 mg/kg, ip daily, for 5 consecutive days, resulted in a 55% increase in life span (% ILS) while administration of 8a,b in the same manner at 200 mg/kg caused a 29% ILS. Treatment with 7a,b to mice with drug-resistant L1210 sublines (5-FU and araC) resulted in 22 and 57% increases in life span, respectively. Lewis lung carcinoma and M5076 sarcoma in mice also responded to the administration of 7a,b with reductions in tumor growth for both tumors and significant increases in life span in mice with Lewis lung carcinoma. Although the mechanism of action of 7a,b is not known, it has been found to be a relatively fast-acting, cell-cycle nonspecific cytotoxic agent that decreases [3H]deoxyuridine incorporation, blocks L1210 cells at the G2 phase of the cell cycle, and is not reversed by exogenous thymidine. These 2'-fluorinated isonucleosides have demonstrated biological activity and may have potential as antitumor drugs.

The fluoroquinolone derivatives have been shown to inhibit human immunodeficiency virus (HIV) replication at the transcriptional level. We confirmed the anti-HIV activity of the most potent congener, 8-difluoromethoxy-1-ethyl-6-fluoro-1,4-dihydro-7-[4-(2- methoxyphenyl)-1-piperazinyl]-4-quinolone-3-carboxylic acid (K-12), in both acutely and chronically infected cells. K-12 was active against different strains of HIV-1 (including AZT- and ritonavir-resistant HIV-1 strains), HIV-2 and simian immunodeficiency virus, in MT-4, CEM, C8166 and peripheral blood mononuclear cells. In all of these antiviral assay systems, K-12 showed a similar activity (EC50 0.2-0.6 microM). K-12 inhibited Moloney murine sarcoma virus-induced transformation of C3H/3T3 cells with an EC50 of 6.9 microM. Also, K-12 proved inhibitory to herpesvirus saimiri, human cytomegalovirus, varicella-zoster virus and herpes simplex virus types 1 and 2 (in order of decreasing sensitivity), but was not inhibitory (at subtoxic concentrations) to human herpesvirus type 8 (as evaluated in BCBL-1 cells), vaccinia virus, Sindbis virus, vesicular stomatitis virus, respiratory syncytial virus, Coxsackie virus, Punta Toro virus, parainfluenza virus or reovirus. Time-of-addition experiments and quantitative transactivation bioassays indicated that K-12 inhibits the Tat-mediated transactivation process in HIV-infected cells.

Because of its unique ability of revealing an object’s internal structures, Computed Tomography (CT) has gained interest in many industrial fields for e.g. defect detection and reverse engineering. With the fast development of better X-ray sources, smaller X-ray detector pixel resolutions, and faster image reconstruction and analysis tools, the performance of industrial CT has been significantly improved. Recently, X-ray CT technology has entered the application field of dimensional metrology, as an alternative to tactile and optical 3D coordinate measuring technique. Nevertheless, the measurement quality of industrial CT machines is affected by many parameters, among which beam hardening plays a crucial role. It has been proven that the accuracy and uncertainty of CT dimensional measurements is largely influenced by the applied beam hardening correction method. As a routine procedure in industry, the beam hardening effect is corrected by applying hardware pre-filtration complemented with a software correction that implies linearization using predefined polynomial fitting curves. This correction method can largely eliminate beam hardening artifacts e.g. cupping effect and streaks. However, measurement results reveal that the effectiveness of such method is closely related to the selected X-ray power and hardware filter. Overcorrection often occurs with inappropriate machine settings, which results in dimensional errors. This paper investigates the correlation between X-ray power, filter and beam hardening correction algorithm, and aims at establishing a procedure for defining the optimal parameters for CT metrology applications. Keywords Computed tomography, Metrology, Beam hardening correction

Sodium 2-mercaptoethanesulfonate reacts with the metal ions Pd(II), Pt(II), Ag(I), Cd(II) and Zn(II) to yield complexes containing multiple anionic sulfonate sites. On the basis of spectroscopic and other analytical data the complexes were assigned the tentative molecular formulas: Pd6(SCH2CH2SO3Na)12, Ptn(SCH2CH2SO3Na)2n+2, Agn(SCH2CH2SO3Na)n, Na2Zn4(SCH2CH2SO3Na)10, and Na2Cd4(SCH2CH2SO3Na)10. The complexes displayed a variety of differences in activity towards DNA and RNA viruses. The platinum complex showed no measurable cytotoxicity and exhibited a spectrum of antiviral activity resembling that of dextran sulfate. It was active against HIV-1 and HIV-2, herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), thymidine kinase-deficient HSV-1, human cytomegalovirus, vesicular stomatitis virus (VSV), influenza A virus, respiratory syncytial virus (RSV), Sindbis virus, Junin virus and Tacaribe virus. The palladium complex also showed no measurable cytotoxicity, but was completely inactive against most viruses, with one notable exception: both HIV-1 and HIV-2 were substantially inhibited by the palladium complex. The silver complex showed significantly less antiviral activity and greater cytotoxicity than the platinum complex but did show some selectivity against RSV. The zinc complex showed only modest activity against VSV, RSV, Junin virus, and Tacaribe virus, and like the silver compound was more cytotoxic than either the platinum or palladium complex. The cadmium complex was toxic to all of the cell lines used for in vitro evaluation of antiviral activity. Based on these results, the platinum and palladium compounds appear to be promising candidates for further studies, that is, as vaginal microbicides in the prevention of genital HIV and/or HSV transmission.