A Measurement of the Proton Structure Function F ⁣2(x,Q2)F_{\!2}(x,Q^2)

A measurement of the proton structure function $F_{\!2}(x,Q^2)$ is reported for momentum transfer squared $Q^2$ between 4.5 $GeV^2$ and 1600 $GeV^2$ and for Bjorken $x$ between $1.8\cdot10^{-4}$ and 0.13 using data collected by the HERA experiment H1 in 1993. It is observed that $F_{\!2}$ increases significantly with decreasing $x$, confirming our previous measurement made with one tenth of the data available in this analysis. The $Q^2$ dependence is approximately logarithmic over the full kinematic range covered. The subsample of deep inelastic events with a large pseudo-rapidity gap in the hadronic energy flow close to the proton remnant is used to measure the "diffractive" contribution to $F_{\!2}$.Comment: 32 pages, ps, appended as compressed, uuencoded fil

Lack of activity of artemether for prophylaxis and treatment of

Artemisinin and its derivatives have been found effective in vivo against Plasmodium and in vitro against Toxoplasma gondii and Pneumocystis carinii. We tested the activity of artemether for prophylaxis and treatment in the rat model of concurrent T. gondii and P. carinii infection. Artemether at doses of 18 and 100 mg/kg administered (s.c.) in prophylaxis did not prevent toxoplasmosis or pneumocystosis, while trimethoprim-sulfamethoxazole (reference treatment) was effective for prevention of both infections. Similar results were obtained in curative studies. These results do not support the use of artemether for prevention or treatment of toxoplasmosis or pneumocystosis

Prediction of Quinolone Activity against Mycobacterium avium by Molecular Topology and Virtual Computational Screening

We conducted a quantitative structure-activity relationship study using a database of 158 quinolones previously tested against Mycobacterium avium-M. intracellulare complex in order to develop a model capable of predicting the activity of new quinolones against the M. avium-M. intracellulare complex in vitro. Topological indices were used as structural descriptors and were related to anti-M. avium-M. intracellulare complex activity by using the linear discriminant analysis (LDA) statistical technique. The discriminant equation thus obtained correctly classified 137 of the 158 quinolones, including 37 of a test group of 44 randomly chosen compounds. This model was then applied to 24 quinolones, including recently developed fluoroquinolones, whose MICs were subsequently determined in vitro by using the Alamar blue microplate assay; the biological results confirmed the model’s predictions. The MICs of these 24 quinolones were then treated by multilinear regres-sion (MLR) to establish a model capable of classifying them according to their in vitro activities. Using this model, a good correlation between measured and predicted MICs was found (r 2 � 0.88; r 2 cv [cross-validation correlation] � 0.82). Moxifloxacin, sparfloxacin, and gatifloxacin were the most potent against the M. avium-M. intracellulare complex, with MICs of 0.2, 0.4, and 0.9 �g/ml, respectively. Finally, virtual modifications o