BASE-STEP: A transportable antiproton reservoir for fundamental interaction studies.

Currently, the world's only source of low-energy antiprotons is the AD/ELENA facility located at CERN. To date, all precision measurements on single antiprotons have been conducted at this facility and provide stringent tests of fundamental interactions and their symmetries. However, magnetic field fluctuations from the facility operation limit the precision of upcoming measurements. To overcome this limitation, we have designed the transportable antiproton trap system BASE-STEP to relocate antiprotons to laboratories with a calm magnetic environment. We anticipate that the transportable antiproton trap will facilitate enhanced tests of charge, parity, and time-reversal invariance with antiprotons and provide new experimental possibilities of using transported antiprotons and other accelerator-produced exotic ions. We present here the technical design of the transportable trap system. This includes the transportable superconducting magnet, the cryogenic inlay consisting of the trap stack and detection systems, and the differential pumping section to suppress the residual gas flow into the cryogenic trap chamber.

In vitro sensitivity of Plasmodium falciparum to halofantrine compared with chloroquine, quinine and mefloquine in the region of Bobo-Dioulasso, Burkina Faso (West Africa).

The in vitro sensitivity of P. falciparum drug-resistant isolates was evaluated in the region of Bobo-Dioulasso during the 1995 and 1996 rainy seasons. Two routinely used antimalarials (chloroquine and quinine) and two new antimalarials (mefloquine and halofantrine) were assessed using 24-hour in vitro cultures with tritiated hypoxanthine and a parasite density > or = 4,000/microl of blood. The proportion of chloroquine-resistant isolates was 20% in 1995 and 19% in 1996, whilst in 1996, the proportion of isolates resistant to halofantrine was greater than in 1995 (9.6% versus 1%). No significant differences were seen in the mean IC50 values in relation to the susceptibility of chloroquine-resistant or chloroquine-sensitive isolates to mefloquine and halofantrine. In the case of quinine, the mean IC50 values were significantly higher in chloroquine-resistant isolates than in chloroquine-sensitive ones. A significant positive correlation was found between the following IC50 values: chloroquine versus quinine, quinine versus mefloquine and mefloquine versus halofantrine.