Analytical Solutions of a Space-Time Fractional Derivative of Groundwater Flow Equation

The classical Darcy law is generalized by regarding the water flow as a function of a noninteger order derivative of the piezometric head. This generalized law and the law of conservation of mass are then used to derive a new equation for groundwater flow. Two methods including Frobenius and Adomian decomposition method are used to obtain an asymptotic analytical solution to the generalized groundwater flow equation. The solution obtained via Frobenius method is valid in the vicinity of the borehole. This solution is in perfect agreement with the data observed from the pumping test performed by the institute for groundwater study on one of their boreholes settled on the test site of the University of the Free State. The test consisted of the pumping of the borehole at the constant discharge rate Q and monitoring the piezometric head for 350 minutes. Numerical solutions obtained via Adomian method are compared with the Barker generalized radial flow model for which a fractal dimension for the flow is assumed. Proposition for uncertainties in groundwater studies was given

Electrical resistivity tomography of the Douala-Massoumbou Paleocene- Eocene aquifer (Cameroon Atlantic Margin)

The Paleocene aquifer of the Douala-Massoumbou sub basin is a rhythmic sequence of sand and shale deposits. Resistivity pseudosections and profiles of half-distance between current electrodes of 350m were acquired at 20 different sites of the Douala-Massoumbou subbasin. These data coupled with mud and gamma-ray logging of deep groundwater boreholes led to the identification of two major sand sequences through the  Paleaocene-Eocene stratigraphic section. The upper sequence associated with Ypresian 30-50 m thick unconformity made up with semi-conductive records, is punctuated by lenses of substantially water bearing sand (WBS). While the lower sequence locally associated with H2S and iron pollution plumes, displays high conductive records. In such sequences, the  distribution of sand and clay deposits settled by channel incision appears fundamental in predicting reservoir geometry and the hydrological potential of the Paleocene WBS.Keywords: Sag basin, electrical tomography, Paleocene formation, water-bearing sand.L’aquifère du Paléocène du sous-bassin de Douala-Massoumbou est une séquence rythmique de dépôts de sable et d’argile. Des sondages géoélectriques tripole (OA=350m) et des tomographies de résistivitéont été acquis sur 20 sites différents de la zone de faible enfouissement de cet aquifère. Ces données, couplées aux résultats des diagraphies gamma-ray et des déblais des forages hydrogéologiques profonds, ont permis d’identifier deux séquences de sable hydrostratigraphique au sein de l’aquifère paléocèneéocène. La séquence supérieure semi-conductrice correspond à dépôts de sable aquifère sain, épaisse de 30 à 50 m et associés à la discordance ypresienne. La séquence inférieure très conductrice, correspond à des chenaux de sable aquifère pollué par le sulfure d’hydrogène (H2S) et le fer. La mise en corrélation de l’ensemble des résultats obtenus a permis de constater que la prise en compte du développement spatial des chemins hydrologiques fossiles est un critère fondamental pour la prédire la distribution et l’exploitation des niveaux de sable aquifère sain du Paléocène du sous-bassin de Douala-Massoumbou.Mots clés: Bassin de fossé d’éffondrement, tomographie électrique, Formation paléocène, Sag basin, electrical tomography, Paleocene formation, niveaux de sable aquifère sain

Prise en charge de la douleur post-operatoire immediate en salle de soins post interventionnels

15 à 50 % des opérés font l'expérience des douleurs post opératoires en dépit des traitements analgésiques. Le but de ce travail a été d'évaluer la prise en charge de la douleur post opératoire (DPO)en salle de soins post interventionnels (SPPI). Il s'agit dune étude prospective et descriptive réalisée dans le service d'anesthésie et de réanimation de l'Hôpital Général de Yaoundé, République du Cameroun. Ont été inclus dans cette étude des patients âgés de plus de 15 ans admis en salle de soins post interventionnels et capables d'utiliser les différentes échelles d'évaluation de la douleur (échelle visuelle analogique, échelle numérique, échelle verbale simple). La DPO a été évaluée et les patients ont été traités. Les résultats ont été présentés sous forme de moyennes et de pourcentages. Le test de chi carré a été utilisé pour la comparaison des valeurs. 174 patients ont été recrutés, âgés de 34 ans en moyenne. Le sex ratio a été d'un homme pour 5 femmes. La majorité des interventions chirurgicales a été faite sous anesthésie générale (91 %). L'incidence des DPO a été de 94 %. La fréquence des DPO a été élevée dans les chirurgies orthopédique (13 cas soit 100 %) et gynéco obstétrique (118 cas soit 97,5 %) La Noramidopyrine a été l'antalgique le plus prescrit (73 % des patients). 4 % des patients ont présenté des effets indésirables dus au traitement. La lutte contre la DPO requiert une bonne évaluation de la douleur, des protocoles thérapeutiques adaptés et une surveillance clinique rigoureuse. Clinics in Mother and Child Health Vol. 3(1) 2006: 473-47

Differential diagnosis of skin ulcers in a Mycobacterium ulcerans endemic area : data from a prospective study in Cameroon

Background Clinical diagnosis of Buruli ulcer (BU) due to Mycobacterium ulcerans can be challenging. We aimed to specify the differential diagnosis of skin lesions in a BU endemic area. Method We conducted a prospective diagnostic study in Akonolinga, Cameroon. Patients presenting with a skin ulcer suspect of BU were included. M. ulcerans was detected using swabs for Ziehl-Neelsen staining, PCR and culture. Skin punch biopsies were taken and reviewed by two histopathologists. Photographs of the lesions were taken and independently reviewed by two dermatologists. Final diagnosis was based on consensus, combining the results of laboratory tests and expert opinion. Results/Discussion Between October 2011 and December 2013, 327 patients with ulcerative lesions were included. Median age was 37 years (0 to 87), 65% were males, and 19% HIV-positive. BU was considered the final diagnosis for 27% of the lesions, 85% of which had at least one positive laboratory test. Differential diagnoses were vascular lesions (22%), bacterial infections (21%), post-traumatic (8%), fistulated osteomyelitis (6%), neoplasia (5%), inflammatory lesions (3%), hemopathies and other systemic diseases (2%) and others (2%). The proportion of BU was similar between HIV-positive and HIV-negative patients (27.0% vs. 26.5%; p = 0.940). Half of children below 15 years of age were diagnosed with BU, compared to 26.8% and 13.9% among individuals 15 to 44 years of age and above, respectively (chi2 p< 0.001). Children had more superficial bacterial infections (24.3%) and osteomyelitis (11.4%). Conclusion We described differential diagnosis of skin lesions in a BU endemic area, stratifying results by age and HIV-status

Contribution Of Autopsy To Medical Practice In Cameroon: A 10 year review.

Of 12.000 bodies received at the mortuary of the Yaounde General Hospital, 126 were autopsied in this 10-year retrospective study from 1997 to 2007, giving a rate of 1 autopsy in 100 deaths. 72.2% of cases were males against 27.8% females. The predominant age group was 20-69 years (57.1%). The main causes of death include natural disease (32.5%), physical aggression (20.6%), road traffic accident (19.8%), poisoning (9.5%), asphyxia (7.1%) and firearm injury (6.4%). The indication for autopsy was mainly medico-legal (91.7%). The circumstances of death showed a predominance of natural causes (34.1%), murder (32.6%), and homicide (28.6%). Though the benefits of an autopsy to the family, medical practice and entire community are enormous, the rate of this procedure in our community is low. We recommend public education and advocate for a legislative framework thatregulates autopsy practice, at least, in teaching hospitals in our country

Role of Anopheles (Cellia) rufipes (Gough, 1910) and other local anophelines in human malaria transmission in the northern savannah of Cameroon: a crosssectional survey

Background As part of a study to determine the impact of insecticide resistance on the effectiveness of longlasting insecticide treated nets (LLINs) in the north of Cameroon, the unexpectedly high density and anthropophilic behaviour of Anopheles rufipes lead us to investigate this species bionomics and role in human malaria parasite transmission. Methods For four consecutive years (2011–2014), annual cross-sectional sampling of adult mosquitoes was conducted during the peak malaria season (September-October) in three health districts in northern Cameroon. Mosquitoes sampled by human landing catch and pyrethrum spray catch methods were morphologically identified, their ovaries dissected for parity determination and Anopheles gambiae siblings were identified by molecular assay. Infection with P. falciparum and blood meal source in residual fauna of indoor resting anopheline mosquitoes were determined by enzyme-linked-immunosorbent assays. Results Anopheles gambiae (sensu lato) (s.l.) comprised 18.4% of mosquitoes collected with An. arabiensis representing 66.27% of the sibling species. The proportion of An. rufipes (2.7%) collected was high with a humanbiting rate ranging between 0.441 and 11.083 bites/person/night (b/p/n) and an anthropophagic rate of 15.36%. Although overall the members of An. gambiae complex were responsible for most of the transmission with entomological inoculation rates (EIR) reaching 1.221 infective bites/person/night (ib/p/n), An. arabiensis and An.coluzzii were the most implicated. The roles of An. funestus, An. pharoensis and An. paludis were minor. Plasmodium falciparum circumsporozoite protein rate in Anopheles rufipes varied from 0.6 to 5.7% with EIR values between 0.010 and 0.481 ib/p/n Conclusions The study highlights the epidemiological role of An. rufipes alongside the members of the An.gambiae complex, and several other sympatric species in human malaria transmission during the wet season in northern Cameroon. For the first time in Cameroon, An. rufipes has been shown to be an important local malaria vector, emphasising the need to review the malaria entomological profile across the country as pre-requisite to effective vector management strategies

Diagnostic Value of Histological Analysis of Punch Biopsies in Suspected Cutaneous Buruli Ulcer: A Study on 32 Cases of Confirmed Buruli Ulcer in Cameroon.

Buruli ulcer (BU) is a cutaneous infectious disease caused by Mycobacterium ulcerans. In this prospective study, we aim to clarify the main histopathological features of cutaneous BU based on 4-mm skin punch biopsies and to evaluate the diagnostic value of this method. Between 2011 and 2013, a prospective study was conducted in Cameroon. Dry swabs from ulcerative lesions and fine-needle aspirates of nonulcerative lesions were examined for Ziehl-Neelsen (ZN) staining, followed by PCR targeting IS2404 and culture. Two 4-mm punch biopsies were performed in the center and in the periphery of each lesion. The 364 patients included in the study had 422 lesions (381 were ulcerative and 357 lesions were biopsied). Among the 99 ulcerated lesions with a final diagnosis of BU, histological features for BU were fulfilled in 32 lesions. 32/32 showed subcutaneous necrosis with a neutrophilic inflammatory infiltrate. 26/32 presented alcohol-resistant bacilli confirmed by ZN stain on histology. Punch biopsies help in establishing the correct diagnosis of BU and also in the differential diagnosis of chronic ulcers. The main histological feature for BU is diffuse coagulative necrosis of subcutaneous tissue, with acid-fast bacilli detected by ZN stain

Role of Anopheles (Cellia) rufipes (Gough, 1910) and other local anophelines in human malaria transmission in the northern savannah of Cameroon: a crosssectional survey

Background As part of a study to determine the impact of insecticide resistance on the effectiveness of longlasting insecticide treated nets (LLINs) in the north of Cameroon, the unexpectedly high density and anthropophilic behaviour of Anopheles rufipes lead us to investigate this species bionomics and role in human malaria parasite transmission. Methods For four consecutive years (2011–2014), annual cross-sectional sampling of adult mosquitoes was conducted during the peak malaria season (September-October) in three health districts in northern Cameroon. Mosquitoes sampled by human landing catch and pyrethrum spray catch methods were morphologically identified, their ovaries dissected for parity determination and Anopheles gambiae siblings were identified by molecular assay. Infection with P. falciparum and blood meal source in residual fauna of indoor resting anopheline mosquitoes were determined by enzyme-linked-immunosorbent assays. Results Anopheles gambiae (sensu lato) (s.l.) comprised 18.4% of mosquitoes collected with An. arabiensis representing 66.27% of the sibling species. The proportion of An. rufipes (2.7%) collected was high with a humanbiting rate ranging between 0.441 and 11.083 bites/person/night (b/p/n) and an anthropophagic rate of 15.36%. Although overall the members of An. gambiae complex were responsible for most of the transmission with entomological inoculation rates (EIR) reaching 1.221 infective bites/person/night (ib/p/n), An. arabiensis and An.coluzzii were the most implicated. The roles of An. funestus, An. pharoensis and An. paludis were minor. Plasmodium falciparum circumsporozoite protein rate in Anopheles rufipes varied from 0.6 to 5.7% with EIR values between 0.010 and 0.481 ib/p/n Conclusions The study highlights the epidemiological role of An. rufipes alongside the members of the An.gambiae complex, and several other sympatric species in human malaria transmission during the wet season in northern Cameroon. For the first time in Cameroon, An. rufipes has been shown to be an important local malaria vector, emphasising the need to review the malaria entomological profile across the country as pre-requisite to effective vector management strategies

Identification and Phenotype of MAIT Cells in Cattle and Their Response to Bacterial Infections

Mucosal-associated invariant T (MAIT) cells are a population of innate-like T cells that utilize a semi-invariant T cell receptor (TCR) α chain and are restricted by the highly conserved antigen presenting molecule MR1. MR1 presents microbial riboflavin biosynthesis derived metabolites produced by bacteria and fungi. Consistent with their ability to sense ligands derived from bacterial sources, MAIT cells have been associated with the immune response to a variety of bacterial infections, such as Mycobacterium spp., Salmonella spp. and Escherichia coli. To date, MAIT cells have been studied in humans, non-human primates and mice. However, they have only been putatively identified in cattle by PCR based methods; no phenotypic or functional analyses have been performed. Here, we identified a MAIT cell population in cattle utilizing MR1 tetramers and high-throughput TCR sequencing. Phenotypic analysis of cattle MAIT cells revealed features highly analogous to those of MAIT cells in humans and mice, including expression of an orthologous TRAV1-TRAJ33 TCR α chain, an effector memory phenotype irrespective of tissue localization, and expression of the transcription factors PLZF and EOMES. We determined the frequency of MAIT cells in peripheral blood and multiple tissues, finding that cattle MAIT cells are enriched in mucosal tissues as well as in the mesenteric lymph node. Cattle MAIT cells were responsive to stimulation by 5-OP-RU and riboflavin biosynthesis competent bacteria in vitro. Furthermore, MAIT cells in milk increased in frequency in cows with mastitis. Following challenge with virulent Mycobacterium bovis, a causative agent of bovine tuberculosis and a zoonosis, peripheral blood MAIT cells expressed higher levels of perforin. Thus, MAIT cells are implicated in the immune response to two major bacterial infections in cattle. These data suggest that MAIT cells are functionally highly conserved and that cattle are an excellent large animal model to study the role of MAIT cells in important zoonotic infections