Papers by Souleymane Diallo
Journal of Antimicrobial Chemotherapy, 2020
Background In the perspective of ART-free HIV remission, vertically infected children treated wit... more Background In the perspective of ART-free HIV remission, vertically infected children treated with suppressive ART from early infancy represent an optimal population model to better understand the genetic complexity of the reservoir. Objectives To evaluate the proportion of defective viral population and the genotypic resistance patterns in cell-associated HIV DNA. Methods In a cohort including 93 ART-treated vertically HIV-infected (VHIV) children in Mali with plasma HIV-1 RNA ≤50 copies/mL for at least 6 months, we studied total HIV DNA, percentage of defective genomes and resistance by reverse transcriptase and protease bulk sequencing from whole blood in dried blood spots. Results Children had a median age of 9.9 years at the time of inclusion (IQR = 7.6–13.4) and 3.3 years (IQR = 2–7) at ART initiation; median ART duration was 5.5 years (IQR = 3.7–7.3). The median level of total HIV DNA was 470 copies/106 cells with one patient presenting undetectable HIV DNA (<66 copies/106...
Journal of breath research, Aug 17, 2016
Detection of bacterial urease activity has been utilized successfully to diagnose Helicobacter py... more Detection of bacterial urease activity has been utilized successfully to diagnose Helicobacter pylori (H. pylori). While Mycobacterium tuberculosis (M. tuberculosis) also possesses an active urease, it is unknown whether detection of mycobacterial urease activity by oral urease breath test (UBT) can be exploited as a rapid point of care biomarker for tuberculosis (TB) in humans. We enrolled 34 individuals newly diagnosed with pulmonary TB and 46 healthy subjects in Bamako, Mali and performed oral UBT, mycobacterial sputum culture and H. pylori testing. Oral UBT had a sensitivity and specificity (95% CI) of 70% (46-88%) and 11% (3-26%), respectively, to diagnose culture-confirmed M. tuberculosis disease among patients without H. pylori, and 100% sensitivity (69-100%) and 11% specificity (3-26%) to diagnose H. pylori among patients without pulmonary TB. Stool microbiome analysis of controls without TB or H. pylori but with positive oral UBT detected high levels of non-H. pylori urease...
Proquest Dissertations and Theses Thesis University of Delaware 2007 Publication Number Aai3267142 Isbn 9780549058069 Source Dissertation Abstracts International Volume 68 05 Section B Page 3116 148 P, 2007
2015 17th International Conference on Transparent Optical Networks (ICTON), 2015
Whispering gallery mode (WGM) resonators are particularly interesting platforms for the emerging ... more Whispering gallery mode (WGM) resonators are particularly interesting platforms for the emerging optical Kerr frequency comb generations, as they are able to feature quality (Q) factors above one billion and thus allow comb generations with very low threshold pump power in the sub-mw regime. The flexibility of choosing various optical materials also facilitates the extension of the spectral ranges and applications of such combs. We have thereby investigated the material dispersion of different optical materials that can support 109 Q factors. We find that fluoride crystals have flatter anomalous dispersion profiles, among which, barium fluoride has a very attractive profile for potential broadband Kerr comb generations in the mid-infrared (mid-IR) range. By using an analytical approximation of WGM resonant frequencies in toroidal disk resonators, we also report a systematic study of the cavity dispersion effect on the total group velocity dispersion (GVD). We show that the major radius and the radial transverse mode index play an important role in tailoring the GVD values. The latter one can lead to very different GVD values in a single resonator, which is experimentally evidenced by Kerr comb generations in a magnesium fluoride disk.
Journal de Pédiatrie et de Puériculture, 2009
Infection nosocomiale ; Chirurgie ; Mali Résumé Objectifs.-Déterminer la fréquence des infections... more Infection nosocomiale ; Chirurgie ; Mali Résumé Objectifs.-Déterminer la fréquence des infections nosocomiales, identifier leurs facteurs de risque et déterminer les germes en cause et leurs sensibilités. Matériel et méthodes.-Il s'agissait d'une étude prospective réalisée de 1 er janvier au 31 décembre 2007 sur tous les patients hospitalisés dans le service de chirurgie pédiatrique pendant au moins 48 heures. Les enfants dont l'hospitalisation était inférieure à 48 heures et les patients perdus de vue n'ont pas été inclus. L'infection nosocomiale a été identifiée selon les critères définis par Center for Disease Control (CDC) d'Atlanta. Résultats.-La fréquence était de 7,4 %. L'âge moyen de nos patients était de 8,7 ans. Le sexratio était de 1,66 en faveur des garçons. Le mode de recrutement, le score de National Nosocomial Infection Surveillance System (NNISS), la classification d'Altemeier, le mode d'intervention et la durée d'hospitalisation ont été des facteurs déterminants dans la survenue des infections nosocomiales, avec p < 0,05. Les germes isolés à la culture étaient les suivants : Escherichia coli (15 cas), Staphylococcus aureus (5 cas), Pseudomonas aeruginosa (4 cas), Klebsiella pneumoniae (1 cas), Escherichia cloacae (1 cas) et Escherichia agglomerans (1 cas). Tous ces germes étaient résistants à l'amoxicilline.
BMC Infectious Diseases, 2015
Background: Hepatitis B (HB) infection is common in Mali. However, there is little information on... more Background: Hepatitis B (HB) infection is common in Mali. However, there is little information on molecular and biochemical characteristics of HB carriers. Methods: A group of 1466 adult volunteers was recruited in the district of Bamako. Confirmed HB carriers were tested for HB viral load by quantitative PCR and HBV was genotyped by sequencing of HBS. Fibrosis and hepatitis activity were measured using the Fibrotest-Actitest. A mutation of TP53 at codon 249 (R249S), specific for exposure to aflatoxin, was detected in cell-free DNA extracted from plasma. Results: Overall, 276 subjects were HBsAg-positive (18.8%). Among 152 subjects tested for HBV load, 49 (32.2%) had over 10 4 copies/mL and 16 (10.5%) had levels below the limit of detection. The E genotype was found in 91.1% of carriers. Fibrotest scores ≥ F2 were observed in 52 subjects (35.4%). Actitest scores ≥ A2 were detected in 15 subjects (10.2%) and were correlated with Fibrotest scores (p = 0.0006). Among 105 subjects tested, 60% had detectable levels of R249S copies (>40 copies/mL plasma). Conclusion: Chronic HB carriage in adults in Bamako district is well over epidemic threshold. About 1/3 of carriers have moderate to severe liver fibrosis and 60% have detectable aflatoxin-related TP53 R249S mutation. These results support introduction of anti-HB therapies to reduce the progression towards severe liver disease.
Nous avons fabriqué par procédés de polissage des résonateurs optique à modes de galerie en utili... more Nous avons fabriqué par procédés de polissage des résonateurs optique à modes de galerie en utilisant différents matériaux cristallins (CaF2 et MgF2). Ces résonateurs ont pour finalité première de générer un signal microonde ultra-stable issu d'un oscillateur opto-électronique (OEO). Puis, en s 'appuyant sur les non-linéarités de Kerr, nous générons différents peignes de fréquences optiques dans les résonateurs.
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Optics Express, 2014
We investigate the phase noise performance of optoelectronic oscillators when the optical energy ... more We investigate the phase noise performance of optoelectronic oscillators when the optical energy storage elements are in the following three configurations: a high-Q whispering gallery mode resonator, an optical delay-line and a combination of both elements. The stability properties of these various optical elements are first characterized, and then systematically compared in the optical and in the microwave frequency domains. Subsequently, the spectral purity of the oscillator is theoretically and experimentally examined for each case. When the resonator is used as both delay and filtering element inside the delay-line based oscillator, the generated spurious modes are highly rejected. A spur rejection by more than 53 dB has been demonstrated for the first-neighboring spur.
Clinical Epidemiology and Global Health, 2013
Low income countries seldom possess adequate means to effectively carry out rigorous epidemiologi... more Low income countries seldom possess adequate means to effectively carry out rigorous epidemiological studies in the fight against infectious diseases such as Tuberculosis and Acute Lower Respiratory Infections. To do so, they require solid health infrastructures and qualified researchers trained in the latest laboratory techniques. Where international collaborative programs presently operate in developing countries, the sustainability of research practices often represents a major challenge. The lack of coordination and support between political decision makers and scientific experts also accounts for the inefficiency of existing programs. The GABRIEL network was therefore recently created by the Fondation Mé rieux to help developing countries improve their research capacity for the detection, expertise, characterization, and surveillance of pathogens. The members of GABRIEL, being institutionally and geographically diverse, comprise laboratories, such as academic research laboratories, governmental institutions, and NGOs. GABRIEL's mission is to enhance health research capacity in developing countries by implementing sustainable research projects.
We present Deep Inelastic Neutron Scattering (DINS) measurements of mixtures of liquid ^3He-^4He ... more We present Deep Inelastic Neutron Scattering (DINS) measurements of mixtures of liquid ^3He-^4He in both the superfluid and normal phases. The measurements were performed on the MARI time-of-flight spectrometer at the ISIS pulsed spallation neutron source, at wavevectors 26<= Q <=29 å-1 for four different ^3He concentrations x. From the data, we extract both the condensate fraction n0 and the
Physical Review B, 2005
We have computed the one-body density matrix ρ1 in solid 4 He at T = 0 K using the Shadow Wave Fu... more We have computed the one-body density matrix ρ1 in solid 4 He at T = 0 K using the Shadow Wave Function (SWF) variational technique. The accuracy of the SWF has been tested with an exact projector method. We find that off-diagonal long range order is present in ρ1 for a perfect hcp and bcc solid 4 He for a range of densities above the melting one, at least up to 54 bars. This is the first microscopic indication that Bose Einstein Condensation (BEC) is present in perfect solid 4 He. At melting the condensate fraction in the hcp solid is 5 × 10 −6 and it decreases by increasing the density. The key process giving rise to BEC is the formation of vacancy-interstitial pairs. We also present values for Leggett's upper bound on the superfluid fraction deduced from the exact local density.
Physical Review B, 2011
Neutron-scattering measurements of the dynamic structure factor, S(Q,ω), of liquid 4 He as a func... more Neutron-scattering measurements of the dynamic structure factor, S(Q,ω), of liquid 4 He as a function of pressure at high-momentum transfer,hQ, are presented. At highhQ the dynamics of single atoms in the liquid is observed. From S(Q,ω) the atomic momentum distribution, n(k), the Bose-Einstein condensate fraction, n 0 , and the final-state (FS) broadening function are obtained. The shape of n(k) differs from a classical, Maxwell-Boltzmann distribution with higher occupation of low-momentum states in the quantum liquid. The width of n(k) and the atomic kinetic energy, K , increase with pressure but the shape of n(k) remains approximately independent of pressure. The present observed and Monte Carlo (MC) calculations of K agree within error. The condensate fraction decreases from n 0 = 7.25% ± 0.75% at saturated vapor pressure (p 0) to n 0 = 3.2% ± 0.75% at pressure p = 24 bar, a density dependence that is again reproduced by MC calculations within observed error. The FS function is the contribution to S(Q,ω) arising from the interaction of the struck atom with its neighbors following the scattering. The FS function broadens with increasing pressure reflecting the increased importance of FS effects at higher pressure.
The Pediatric Infectious Disease Journal, 2005
Population-based, bacteriologically confirmed disease burden data aid decision makers in African ... more Population-based, bacteriologically confirmed disease burden data aid decision makers in African countries pondering whether to introduce Haemophilus influenzae type b (Hib) immunization for infants. A bacteriology laboratory was established in Hopital Gabriel Toure, serving Bamako, Mali. Children age 0-15 years with fever &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; or =39 degrees C or syndromes compatible with invasive bacterial disease (meningitis, etc.) were eligible. From 2 to 5 mL of blood or relevant body fluid were inoculated into Bactec Ped Plus/F medium for automated culture; body fluids were also inoculated directly onto solid media. Hib was confirmed by standard microbiologic techniques and antibiograms generated by disk diffusion. From June 1, 2002 to May 31, 2004, 3592 (87.8%) of 4092 children admitted to Hopital Gabriel Toure with high fever or suspected invasive bacterial disease were cultured, including 1745 who were 0-11 months old, 1132 who were 1-4 years old and 715 who were 5-15 years old. Hib was isolated from 207 Bamako children, 81 from blood alone and 124 from cerebrospinal fluid (with or without positive blood culture). Of 207 cases 204 (98.5%) occurred in children younger than age 5 years (annual incidence, 45.2/10) and 159 (77%) in infants age 0-11 months (annual incidence, 158.4/10). Peak incidence (370.0 cases/10) and 12 of 21 Hib deaths occurred in 6- to 7-month-olds. Of the Hib isolates, 11.1% were resistant to ampicillin, 32% to chloramphenicol and 0.5% to ceftriaxone. The substantial burden of invasive Hib disease documented in Bamako has prompted the Malian government to introduce routine infant immunization with Hib conjugate.
Journal of the Physical Society of Japan, 2013
We report the diffusion of water molecules confined in the pores of folded silica materials (FSM-... more We report the diffusion of water molecules confined in the pores of folded silica materials (FSM-12 with average pore diameter of ∼ 16Å), measured by means of quasielastic neutron scattering using the cold neutron chopper spectrometer (CNCS). The goal is to investigate the effect of electric field on the previously observed fast component of nano-confined water. The measurements were taken at temperatures between 220 K and 245 K, and at two electric field values, 0 kV/mm and 2 kV/mm. Similar to the recently observed electric field induced enhancement of the slow translational motion of confined water, there is a an equally important impact of the field on the faster diffusion.
Journal of the American Chemical Society, 2013
Atomistic molecular dynamics (MD) simulations were carried out to investigate the local dynamics ... more Atomistic molecular dynamics (MD) simulations were carried out to investigate the local dynamics of polyelectrolyte dendrimers dissolved in deuterium oxide (D2O) and its dependence on molecular charge. Enhanced segmental dynamics upon increase in molecular charge is observed, consistent with quasielastic neutron scattering (QENS) measurements. A strong coupling between the intradendrimer local hydration level and segmental dynamics is also revealed. Compelling evidence shows these findings originate from the electrostatic interaction between the hydrocarbon components of a dendrimer and the invasive water. This combined study provides fundamental insight into the dynamics of charged polyelectrolytes and the solvating water molecules.
Journal of Clinical Microbiology, 2008
PCR methodology was developed to identify Salmonella enterica serovars Typhi, Paratyphi A, and Pa... more PCR methodology was developed to identify Salmonella enterica serovars Typhi, Paratyphi A, and Paratyphi B. One multiplex PCR identifies serogroup D, A, and B and Vi-positive strains; another confirms flagellar antigen “d,” “a,” or “b.” Blinded testing of 664 Malian and Chilean Salmonella blood isolates demonstrated 100% sensitivity and specificity.
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Papers by Souleymane Diallo