Neutron calorimeter design for pulsed neutron experiment diagnostics.

Neutron calorimeter for diagnostic support of both fission- and fusion-based pulsed neutron experiments is described. The calorimeter generates a voltage signal output via a pair of thermocouples contacting a sample material, which experiences a temperature increase due to interactions with an incident neutron fluence. Advantages of the calorimeter include the versatility derived from its small size, modularity, and the variety of employable neutron absorber materials and sizes. These characteristics permit use with neutron energies between the thermal and fast (up to 14 MeV) spectra. Design overview and requirements, Monte Carlo particle transport simulation results, test data, and possibilities for calorimeter development are provided and discussed.

Therapeutic efficacy of sulfadoxine-pyrimethamine for Plasmodium falciparum malaria.

OBJECTIVES: To assess the therapeutic efficacy of sulfadoxinepyrimethamine (SP) after 5 years of use as first-line treatment of uncomplicated Plasmodium falciparum malaria, and thus guide the selection of artemisinin-based combination therapy in Mpumalanga, South Africa. DESIGN: An open-label, in vivo therapeutic efficacy study of patients with uncomplicated P. falciparum malaria treated with a single oral dose of SP, with response to treatment monitored clinically and parasitologically on days 1, 2, 3, 7, 14, 21, 28 and 42. SETTING: Mangweni and Naas public health care clinics, Tonga district in rural Mpumalanga. SUBJECTS, OUTCOME MEASURES AND RESULTS: Of 152 patients recruited sequentially, 149 (98%) were successfully followed up for 42 days. One hundred and thirty-four patients (90%) demonstrated adequate clinical and parasitological response. Of the 15 patients (10%) who failed treatment, 2 (1.3%) had an early treatment failure, and polymerase chain reaction confirmed recrudescent infection in all 13 patients (8.7%) who had late parasitological (N = 11) or clinical (N = 2) failure. Gametocyte carriage was prevalent following SP treatment (84/152) and this has increased significantly since implementation in 1998 (relative risk 2.77 (confidence interval 1.65 - 4.66); p = 0.00004). CONCLUSION: Asexual P. falciparum parasites in Mpumalanga remain sensitive to SP, with no significant difference between the baseline cure rate (94.5%) at introduction in 1998, and the present 90% cure rate (p = 0.14). However, since gametocyte carriage has increased significantly we recommend that SP be combined with artesunate in Mpumalanga to reduce gametocyte carriage and thus decrease malaria transmission and potentially delay antimalarial resistance.

Community knowledge and perceptions about malaria and practices influencing malaria control in Mpumalanga Province, South Africa.

OBJECTIVE: To assess community knowledge and perceptions about malaria and its control in a rural setting. DESIGN: Descriptive cross-sectional survey. SETTING: Tonga district with a population of 116,418, seasonal malaria with an annual incidence of 3,200 cases. SUBJECTS: Female heads of 299 randomly selected households. METHODOLOGY: A total of 299 households were selected from a random sample of 30 clusters. Community knowledge and perceptions about malaria and its control were assessed by interviews with the female head of each of the 299 selected households. RESULTS: Respondents ranked malaria as the third most serious health problem facing the community after TB and AIDS. Seventy-two per cent (214/299) of respondents reported that they knew what malaria disease was and of these, 92.1% (197/214) mentioned mosquito bites as the cause of malaria. The respondents' understanding of the causal role of mosquitoes in malaria was significantly related to their knowledge about disease symptoms (P < 0.001). Reported community compliance with the malaria control programme (MCP) was satisfactory; 86.6% (259/299) of respondents reported that their homes had been sprayed during the past 2 years but 10.0% (30/299) did not know why homes were sprayed. Hospitals or clinics were the facilities where respondents most commonly sought treatment for fever; 66.9% (200/299) reported that they would seek treatment immediately after the onset of high fever. Specific practices such as replastering or washing of inside walls compromised the effectiveness of the MCP. Personal preventive measures were sometimes used against malaria (50.8%, 152/299) and use was positively associated with education level (P = 0.001). Respondents expressed their desire for more information about malaria and their willingness to contribute to the control of malaria in their community. CONCLUSION: The survey collected information which was directly relevant to the development of health education messages to increase community awareness of the problem of malaria, to emphasise the importance of early diagnosis and prompt treatment of malaria, to improve community understanding of the function of indoor residual spraying, and to enlighten the population of the role of mosquitoes in malaria transmission and the availability and benefits of personal protection measures against mosquito bites.

Using a geographical information system to plan a malaria control programme in South Africa.

INTRODUCTION: Sustainable control of malaria in sub-Saharan Africa is jeopardized by dwindling public health resources resulting from competing health priorities that include an overwhelming acquired immunodeficiency syndrome (AIDS) epidemic. In Mpumalanga province, South Africa, rational planning has historically been hampered by a case surveillance system for malaria that only provided estimates of risk at the magisterial district level (a subdivision of a province). METHODS: To better map control programme activities to their geographical location, the malaria notification system was overhauled and a geographical information system implemented. The introduction of a simplified notification form used only for malaria and a carefully monitored notification system provided the good quality data necessary to support an effective geographical information system. RESULTS: The geographical information system displays data on malaria cases at a village or town level and has proved valuable in stratifying malaria risk within those magisterial districts at highest risk, Barberton and Nkomazi. The conspicuous west-to-east gradient, in which the risk rises sharply towards the Mozambican border (relative risk = 4.12, 95% confidence interval = 3.88-4.46 when the malaria risk within 5 km of the border was compared with the remaining areas in these two districts), allowed development of a targeted approach to control. DISCUSSION: The geographical information system for malaria was enormously valuable in enabling malaria risk at town and village level to be shown. Matching malaria control measures to specific strata of endemic malaria has provided the opportunity for more efficient malaria control in Mpumalanga province.

The effect of amiloride on the airway response to metabisulphite in asthma: a negative report.

Frusemide, a loop diuretic, has been shown to potently inhibit several indirect bronchoconstrictor challenges in asthma. The mechanism by which nebulized frusemide protects against indirect bronchoconstrictor stimuli in asthma is not known. One mechanism could be related to inhibition of sodium transport. If this is the case, then amiloride, another inhibitor of sodium transport, should also protect against indirect bronchoconstrictor challenges. Ten subjects with mild asthma were administered either 10(-2) M amiloride or placebo, by nebulizer, in a double-blind crossover fashion. After each inhalation, forced expiratory volume in one second (FEV1) was recorded at 10 min intervals for 30 min, after which a metabisulphite challenge was performed. No significant difference in the response to metabisulphite was seen between placebo and amiloride treatment. The mean difference in provocative dose of metabisulphite producing a 20% fall in FEV1 (PD20) between placebo and amiloride was 1.015 doubling doses, 95% confidence interval (95% CI) -0.201 to 2.231, (p = 0.09). This result does not support the hypothesis that frusemide is acting to protect against bronchoconstrictor challenges in asthma by an effect on sodium transport.

The Structure of Sweeper Tentacles in the Black Coral Antipathes fiordensis.

Normal tentacles on polyps of the black coral Antipathes fiordensis are less than 2 mm long and display well-defined, wart-like structures, the centers of which are marked by both flagella and microvilli. Both of these microappendages are characteristic of spirocytes, the dominant type of cnidocyte in normal tentacles. Sweeper tentacles, up to 15 mm long, form in apparent response to an alcyonacean epibiont. The external surface of the sweeper tentacle lacks the well-defined, wart-like batteries of the normal tentacle, and exhibits a general reduction in the appearance of surface microappendages. Nonetheless, there is a greater number of cnidae per unit area. No spirocysts are found in these sweeper tentacles. Instead, the cnidom is composed entirely of microbasic b-mastigophores (MbMs). More than 99% of these are of a single type that are structurally different from the MbMs found as a minority of the cnidae in normal tentacles. Changes in sweeper tentacle cnidae are compared with those occurring in modified tentacles of other anthozoans.