140 research outputs found
Exploring the host factors affecting asymptomatic Plasmodium falciparum infection: insights from a rural Burkina Faso study.
BACKGROUND
Asymptomatic Plasmodium falciparum parasitaemia forms a reservoir for the transmission of malaria disease in West Africa. Certain haemoglobin variants are known to protect against severe malaria infection. However, data on the potential roles of haemoglobin variants and nongenetic factors in asymptomatic malaria infection is scarce and controversial. Therefore, this study investigated the associations of iron homeostasis, inflammation, nutrition, and haemoglobin mutations with parasitaemia in an asymptomatic cohort from a P. falciparum-endemic region during the high transmission season.
METHODS
A sub-study population of 688 asymptomatic individuals (predominantly children and adolescents under 15 years, n = 516) from rural Burkina Faso previously recruited by the NOVAC trial (NCT03176719) between June and October 2017 was analysed. Parasitaemia was quantified with conventional haemocytometry. The haemoglobin genotype was determined by reverse hybridization assays targeting a selection of 21 HBA and 22 HBB mutations. Demographics, inflammatory markers (interleukins 6 and 10, hepcidin), nutritional status (mid upper-arm circumference and body mass index), and anaemia (total haemoglobin, ferritin, soluble transferrin receptor) were assessed as potential predictors through logistic regression.
RESULTS
Malaria parasites were detected in 56% of subjects. Parasitaemia was associated most strongly with malnutrition. The effect size increased with malnutrition severity (OR = 6.26, CI95: 2.45-19.4, p < 0.001). Furthermore, statistically significant associations (p < 0.05) with age, cytokines, hepcidin and heterozygous haemoglobin S were observed.
CONCLUSIONS
According to these findings, asymptomatic parasitaemia is attenuated by haemoglobin S, but not by any of the other detected genotypes. Aside from evidence for slight iron imbalance, overall undernutrition was found to predict parasitaemia; thus, further investigations are required to elucidate causality and inform strategies for interventions
Investigation of the thermal stability of Mg/Co periodic multilayers for EUV applications
We present the results of the characterization of Mg/Co periodic multilayers
and their thermal stability for the EUV range. The annealing study is performed
up to a temperature of 400\degree C. Images obtained by scanning transmission
electron microscopy and electron energy loss spectroscopy clearly show the good
quality of the multilayer structure. The measurements of the EUV reflectivity
around 25 nm (~49 eV) indicate that the reflectivity decreases when the
annealing temperature increases above 300\degreeC. X-ray emission spectroscopy
is performed to determine the chemical state of the Mg atoms within the Mg/Co
multilayer. Nuclear magnetic resonance used to determine the chemical state of
the Co atoms and scanning electron microscopy images of cross sections of the
Mg/Co multilayers reveal changes in the morphology of the stack from an
annealing temperature of 305\degreee;C. This explains the observed reflectivity
loss.Comment: Published in Applied Physics A: Materials Science \& Processing
Published at
http://www.springerlink.com.chimie.gate.inist.fr/content/6v396j6m56771r61/ 21
page
Neemazal ® as a possible alternative control tool for malaria and African trypanosomiasis?
Background: Research efforts to identify possible alternative control tools for malaria and African trypanosomiasis are needed. One promising approach relies on the use of traditional plant remedies with insecticidal activities. Methods: In this study, we assessed the effect of blood treated with different doses of NeemAzal ® (NA, neem seed extract) on mosquitoes (Anopheles coluzzii) and tsetse flies (Glossina palpalis gambiensis) (i) avidity to feed on the treated blood, (ii) longevity, and (iii) behavioural responses to human and calf odours in dual-choice tests. We also gauged NeemAzal ® toxicity in mice. Results: In An. coluzzii, the ingestion of NA in bloodmeals offered by membrane feeding resulted in (i) primary antifeedancy; (ii) decreased longevity; and (iii) reduced response to host odours. In G. palpalis gambiensis, NA caused (i) a knock-down effect; (ii) decreased or increased longevity depending on the dose; and (iii) reduced response to host stimuli. In both cases, NA did not affect the anthropophilic rate of activated insects. Overall, the most significant effects were observed with NA treated bloodmeals at a dose of 2000 μg/ml for mosquitoes and 50 μg/ml for tsetse flies. Although no mortality in mice was observed after 14 days of follow-up at oral doses of 3.8, 5.6, 8.4 and 12.7 g/kg, behavioural alterations were noticed at doses above 8 g/kg. Conclusion: This study revealed promising activity of NA on A. coluzzii and G. palpalis gambiensis but additional research is needed to assess field efficacy of neem products to be possibly integrated in vector control programmes
Multifragmentation in Xe(50A MeV)+Sn Confrontation of theory and data
We compare in detail central collisions Xe(50A MeV) + Sn, recently measured
by the INDRA collaboration, with the Quantum Molecular Dynamics (QMD) model in
order to identify the reaction mechanism which leads to multifragmentation. We
find that QMD describes the data quite well, in the projectile/target region as
well as in the midrapidity zone where also statistical models can be and have
been employed. The agreement between QMD and data allows to use this dynamical
model to investigate the reaction in detail. We arrive at the following
observations: a) the in medium nucleon nucleon cross section is not
significantly different from the free cross section, b) even the most central
collisions have a binary character, c) most of the fragments are produced in
the central collisions and d) the simulations as well as the data show a strong
attractive in-plane flow resembling deep inelastic collisions e) at midrapidity
the results from QMD and those from statistical model calculations agree for
almost all observables with the exception of . This
renders it difficult to extract the reaction mechanism from midrapidity
fragments only. According to the simulations the reaction shows a very early
formation of fragments, even in central collisions, which pass through the
reaction zone without being destroyed. The final transverse momentum of the
fragments is very close to the initial one and due to the Fermi motion. A
heating up of the systems is not observed and hence a thermal origin of the
spectra cannot be confirmed.Comment: figures 1 and 2 changed (no more ps -errors
Study of intermediate velocity products in the Ar+Ni collisions between 52 and 95 A.MeV
Intermediate velocity products in Ar+Ni collisions from 52 to 95 A.MeV are
studied in an experiment performed at the GANIL facility with the 4
multidetector INDRA. It is shown that these emissions cannot be explained by
statistical decays of the quasi-projectile and the quasi-target in complete
equilibrium. Three methods are used to isolate and characterize intermediate
velocity products. The total mass of these products increases with the violence
of the collision and reaches a large fraction of the system mass in mid-central
collisions. This mass is found independent of the incident energy, but strongly
dependent on the geometry of the collision. Finally it is shown that the
kinematical characteristics of intermediate velocity products are weakly
dependent on the experimental impact parameter, but strongly dependent on the
incident energy. The observed trends are consistent with a
participant-spectator like scenario or with neck emissions and/or break-up.Comment: 37 pages, 13 figure
Measurements of sideward flow around the balance energy
Sideward flow values have been determined with the INDRA multidetector for
Ar+Ni, Ni+Ni and Xe+Sn systems studied at GANIL in the 30 to 100 A.MeV incident
energy range. The balance energies found for Ar+Ni and Ni+Ni systems are in
agreement with previous experimental results and theoretical calculations.
Negative sideward flow values have been measured. The possible origins of such
negative values are discussed. They could result from a more important
contribution of evaporated particles with respect to the contribution of
promptly emitted particles at mid-rapidity. But effects induced by the methods
used to reconstruct the reaction plane cannot be totally excluded. Complete
tests of these methods are presented and the origins of the
``auto-correlation'' effect have been traced back. For heavy fragments, the
observed negative flow values seem to be mainly due to the reaction plane
reconstruction methods. For light charged particles, these negative values
could result from the dynamics of the collisions and from the reaction plane
reconstruction methods as well. These effects have to be taken into account
when comparisons with theoretical calculations are done.Comment: 27 pages, 15 figure
BMJ Open
OBJECTIVES: The aim of this study was to estimate alcohol and tobacco use prevalence and their correlates among female sex workers (FSW), men who have sex with men (MSM) and drug users (DU) in Togo. DESIGN, SETTING AND PARTICIPANTS: A cross-sectional bio-behavioural study was conducted among 2115 MSM, FSW and DU in 2017 using a respondent-driven sampling method, in the eight biggest towns of Togo. Selection criteria for the MSM were being male and having had oral or anal intercourse with a man in the previous 12 months; for FSW, being a female and having exchanged sex for money in the previous 12 months; and for DU, consuming heroin, cocaine or hashish for MSM, FSW and DU, respectively. All participants had to be at least 18 years old and residing in the territory for the past 3 months. RESULTS: The prevalence of alcohol consumption, hazardous/harmful consumption and binge drinking was 64.8%, 38.4% and 45.5%, respectively. Current tobacco use was reported by 30.6% of participants and HIV prevalence was estimated at 12.5%. DU were more likely to engage in binge drinking compared with other key populations (adjusted odds ratio (aOR)=2.0; 95% CI 1.4 to 2.8; p=0.001). Participants who were identified as having hazardous/harmful alcohol consumption had almost three times the odds of tobacco consumption than those with no risky consumption (aOR=2.6; 95% CI 2.0 to 3.4; p=0.001). Hazardous/harmful alcohol consumption was three times more likely among participants with severe psychological distress compared with those with no psychological distress (aOR=3.3, 95% CI 2.2 to 5.1; p=0.001). CONCLUSION: Findings from this study demonstrate the need for the integration of mental health and substance abuse reduction interventions into HIV prevention programme, particularly those geared towards key populations
PLoS One
CONCLUSION: This study showed the diversity of circulating HPV genotypes in Togo. Programs of HPV vaccination and early detection of benign or precancerous lesions should be implemented to reduce cancer-related comorbidities
Emission time scale of light particles in the system Xe+Sn at 50 AMeV. A probe for dynamical emission ?
Proton and deuteron correlation functions have been investigated with both
impact parameter and emission source selections. The correlations of the system
(129Xe + natSn) at 50 AMeV have been measured with the 4 pi INDRA which
provides a complete kinematical description of each event. The emission time
scale analyzed with a quantum model reveals the time sequence of the light
particles emitted by the projectile-like fragment. The short and constant
emission time of the proton, independent of the impact parameter, can be
attributed to a preequilibrium process.Comment: 20 pages, with 11 included figures; Accepted by European Physics
Journal
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