Effect of phytase on zinc absorption from a millet-based porridge fed to young Burkinabe children.

BACKGROUND/OBJECTIVES: Fortifying cereal staples with zinc is a strategy for increasing zinc intake in young children in developing countries. However, phytic acid (PA) naturally present in cereals strongly decreases zinc absorption. A stable-isotope zinc absorption study was conducted in young children to investigate the ability of the PA-degrading enzyme phytase to improve zinc absorption, when added to a cereal porridge immediately before consumption. SUBJECTS/METHODS: Fractional absorption of zinc (FAZ) was estimated in 35 young healthy Burkinabe children using the double-isotopic tracer ratio method with 67Zn as oral tracer and 70Zn as intravenous tracer, in a crossover design. The test meals were: (a) a millet-based porridge containing 1.4 mg total zinc (native plus 1 mg added as ZnSO4) with a PA:Zn molar ratio of 7.7; (b) the same porridge with the enzyme phytase (20.5 phytase units (FTU)) added immediately before consumption. The exchangeable zinc pool (EZP) was determined as a potential measure of long-term zinc intake in 20 of the 35 children and compared with FAZ. RESULTS: Mean FAZ increased from 9.5±3.4 to 16.0±5.1% (P<0.0001), when phytase was added to the meal. The mean EZP was 3.6±0.5 mg/kg. There was no correlation between the EZP and FAZ values for either of the two test meals. CONCLUSIONS: Adding phytase immediately prior to consumption of a zinc-fortified cereal-based complementary food can improve zinc absorption in young children.

Energy ordering of grain boundaries in Cr2O3: insights from theory.

The grain boundaries (GBs) of corundum Cr2O3 are known to play an important role in the diffusion of ions within the oxide, which is an important phenomenon for the corrosion of stainless steels. The extent of the growth of oxide layers in stainless steel depends upon which interfaces are preferred within Cr2O3. Therefore, we have constructed four different grain boundary planes (rhombohedral, basal, prismatic and pyramidal) and their various associated interface symmetries known in literature for corundum Al2O3. Their structural, electronic, and energetic properties are investigated theoretically with periodic boundary conditions using the DFT + U approach. We find that the prismatic screw GB with a Cr­O plane interface is the energetically preferred GB with the rhombohedral GB with screw symmetry and Cr vacancy termination being the second energetically preferred GB. The increase of the number of in-plane Cr atoms at the interface of prismatic GB enhances the stability, which is also evident in the electronic density of states.

Bacillus amyloliquefaciens ssp. plantarum strains as potential protective starter cultures for the production of Bikalga, an alkaline fermented food.

AIMS: To identify and screen dominant Bacillus spp. strains isolated from Bikalga, fermented seeds of Hibiscus sabdariffa for their antimicrobial activities in brain heart infusion (BHI) medium and in a H. sabdariffa seed-based medium. Further, to characterize the antimicrobial substances produced. METHODS AND RESULTS: The strains were identified by gyrB gene sequencing and phenotypic tests as B. amyloliquefaciens ssp. plantarum. Their antimicrobial activity was determined by the agar spot and well assay, being inhibitory to a wide range of Gram-positive and Gram-negative pathogenic bacteria and fungi. Antimicrobial activity against Bacillus cereus was produced in H. sabdariffa seed-based medium. PCR results revealed that the isolates have potential for the lipopeptides iturin, fengycin, surfactin, the polyketides difficidin, macrolactin, bacillaene and the dipeptide bacilysin production. Ultra-high-performance liquid chromatography-time of flight mass spectrometry analysis of antimicrobial substance produced in BHI broth allowed identification of iturin, fengycin and surfactin. CONCLUSIONS: The Bacillus amyloliquefaciens ssp. plantarum exhibited broad-spectrum antifungal and antibacterial properties. They produced several lipopeptide antibiotics and showed good potential for biological control of Bikalga. SIGNIFICANCE AND IMPACT OF THE STUDY: Pathogenic bacteria often occur in spontaneous food fermentations. This is the first report to identify indigenous B. amyloliquefaciens ssp. plantarum strains as potential protective starter cultures for safeguarding Bikalga.

Reactive molecular dynamics of the initial oxidation stages of Ni111 in pure water: effect of an applied electric field.

Corrosion processes occurring in aqueous solutions are critically dependent upon the interaction between the metal electrode and the solvent. In this work, the interaction of a nickel substrate with water molecules has been investigated using reactive force field (ReaxFF) molecular dynamics simulations. This approach was originally developed by van Duin and co-workers to study hydrocarbon chemistry and the catalytic properties of organic compounds. To our knowledge, this method has not previously been used to study the corrosion of nickel. In this work, we studied the interaction of 480 molecules of water (ρ = 0.99 g·cm(-3)) with Ni(111) surfaces at 300 K. The results showed that a water "bilayer" was adsorbed on the nickel surface. In the absence of an applied electric field, no dissociation of water was observed. However, the nickel atoms at the surface were charged positively, whereas the first water layer was charged negatively, indicating the formation of an electric double layer. To study the corrosion of nickel in pure water, we introduced an external electric field between the metal and the solution. The electric field intensity varied between 10 and 20 MeV/cm. The presence of this electric field led to oxidation of the metal surface. The structural and morphological differences associated with the growth of this oxide film in the presence of the electric field were evaluated. The simulated atomic trajectories were used to analyze the atomic displacement during the reactive process. The growth of the oxide scale on the nickel surface was primarily due to the movement of anions toward the interior of the metal substrate and the migration of nickel toward the free surface. We found that increasing the electric field intensity sped up the corrosion of nickel. The results also showed that the oxide film thickness increased linearly with increasing electric field intensity.

The microbiology of Bandji, palm wine of Borassus akeassii from Burkina Faso: identification and genotypic diversity of yeasts, lactic acid and acetic acid bacteria.

AIM: To investigate physicochemical characteristics and especially genotypic diversity of the main culturable micro-organisms involved in fermentation of sap from Borassus akeassii, a newly identified palm tree from West Africa. METHODS AND RESULTS: Physicochemical characterization was performed using conventional methods. Identification of micro-organisms included phenotyping and sequencing of: 26S rRNA gene for yeasts, 16S rRNA and gyrB genes for lactic acid bacteria (LAB) and acetic acid bacteria (AAB). Interspecies and intraspecies genotypic diversities of the micro-organisms were screened respectively by amplification of the ITS1-5.8S rDNA-ITS2/16S-23S rDNA ITS regions and repetitive sequence-based PCR (rep-PCR). The physicochemical characteristics of samples were: pH: 3.48-4.12, titratable acidity: 1.67-3.50 mg KOH g(-1), acetic acid: 0.16-0.37%, alcohol content: 0.30-2.73%, sugars (degrees Brix): 2.70-8.50. Yeast included mainly Saccharomyces cerevisiae and species of the genera Arthroascus, Issatchenkia, Candida, Trichosporon, Hanseniaspora, Kodamaea, Schizosaccharomyces, Trigonopsis and Galactomyces. Lactobacillus plantarum was the predominant LAB species. Three other species of Lactobacillus were also identified as well as isolates of Leuconostoc mesenteroides, Fructobacillus durionis and Streptococcus mitis. Acetic acid bacteria included nine species of the genus Acetobacter with Acetobacter indonesiensis as predominant species. In addition, isolates of Gluconobacter oxydans and Gluconacetobacter saccharivorans were also identified. Intraspecies diversity was observed for some species of micro-organisms including four genotypes for Acet. indonesiensis, three for Candida tropicalis and Lactobacillus fermentum and two each for S. cerevisiae, Trichosporon asahii, Candida pararugosa and Acetobacter tropicalis. CONCLUSION: fermentation of palm sap from B. akeassii involved multi-yeast-LAB-AAB cultures at genus, species and intraspecies level. SIGNIFICANCE AND IMPACT OF THE STUDY: First study describing microbiological and physicochemical characteristics of palm wine from B. akeassii. Genotypic diversity of palm wine LAB and AAB not reported before is demonstrated and this constitutes valuable information for better understanding of the fermentation which can be used to improve the product quality and develop added value by-products.

Biomolecule-biomaterial interaction: a DFT-D study of glycine adsorption and self-assembly on hydroxylated Cr2O3 surfaces.

The adsorption of glycine, the building block of amino acids, on hydroxylated (0001)-Cr2O3 model surfaces, representing the stainless steel passive film surface, was modeled by means of the GGA + U method. The roles of glycine coverage and surface termination (hydroxylated Cr- and O-terminated surfaces) on the adsorption mode and self-assembly properties were explored. The hydroxylated Cr-terminated Cr2O3 surface, which presents two types of (H)OH groups exhibiting different acidic character, is more reactive than the hydroxylated O-terminated surface, where one single type of OH group is present, for all adsorption modes and coverages considered. Outer sphere adsorption occurs in the zwitterion form, stabilized at low coverage through H-bond formation with coadsorbed water molecules, and at the monolayer coverage by glycine self-assembling. The OH substitution by glycinate is favored on the hydroxylated Cr-terminated surface and not on the O-terminated one. The inclusion of dispersion forces does not change the observed tendencies. An atomistic thermodynamics approach suggests that outer sphere adsorption is thermodynamically favored over inner sphere adsorption in the whole domain of glycine concentration. The obtained SAM's free energies of formation are rationalized in a model considering the balance between sublimation and solvation free energies, and extrapolated to other amino acids, to predict the SAMs formation above hydroxylated surfaces. It is found that hydrophobic AA tend to self-assemble at the surface, whereas hydrophilic ones do not.

Genotypic diversity of lactic acid bacteria isolated from African traditional alkaline-fermented foods.

AIM: To identify and compare lactic acid bacteria (LAB) isolated from alkaline fermentations of cassava (Manihot esculenta Crantz) leaves, roselle (Hibiscus sabdariffa) and African locust bean (Parkia biglobosa) seeds for production of, respectively, Ntoba Mbodi, Bikalga and Soumbala. METHODS AND RESULTS: A total of 121 LAB were isolated, identified and compared by phenotyping and genotyping using PCR amplification of 16S-23S rDNA intergenic transcribed spacer (ITS-PCR), repetitive sequence-based PCR (rep-PCR) and DNA sequencing. The results revealed a diversity of genera, species and subspecies of LAB in African alkaline fermentations. The isolates were characterized as nonmotile (in most cases) Gram-positive rods, cocci or coccobacilli, catalase and oxidase negative. ITS-PCR allowed typing mainly at species level, with differentiation of a few bacteria at subspecies level. Rep-PCR permitted typing at subspecies level and revealed significant genotypic differences between the same species of bacteria from different raw materials. DNA sequencing combined with use of API 50CHL and API 20Strep systems allowed identification of bacteria as Weissella confusa, Weissella cibaria, Lactobacillus plantarum, Pediococcus pentosaceus, Enterococcus casseliflavus, Enterococcus faecium, Enterococcus faecalis, Enterococcus avium and Enterococcus hirae from Ntoba Mbodi; Ent. faecium, Ent. hirae and Pediococcus acidilactici from Bikalga and Soumbala. CONCLUSION: LAB found in African alkaline-fermented foods belong to a range of genera, species and subspecies of bacteria and vary considerably according to raw material. SIGNIFICANCE AND IMPACT OF THE STUDY: Our study confirms that LAB survive in alkaline fermentations, a first crucial stage in determining their significance and possible value as probiotic bacteria.

Potential of amylolytic lactic acid bacteria to replace the use of malt for partial starch hydrolysis to produce African fermented pearl millet gruel fortified with groundnut.

Fermentation and starch hydrolysis of a pre-cooked pearl millet-groundnut (MG) slurry inoculated with amylolytic lactic acid bacteria (ALAB) or by back slopping was investigated as a substitute for the addition of malt to prepare infant gruels. The ALAB collection strain Lb. plantarum A6, and the endogenous microflora provided by back slopping were more efficient in acidifying and partially hydrolysing starch in the MG slurry than Lb. plantarum 6.1, isolated from the traditional process in Burkina Faso. Large amounts of maltotriose and maltotetraose accumulated in slurry fermented by strain A6. No accumulation of maltose was observed, which could be an advantage to prevent the growth of microbial contaminants such as yeasts. Starch hydrolysis in the MG slurry inoculated with strain A6 or by back slopping enabled preparation of high-energy density gruels (84.7+/-4.4 and 80.4+/-23.8 kcal/100 g of gruel, respectively) of liquid consistency. However variability was higher with back slopping.

Enzyme activities of lactic acid bacteria from a pearl millet fermented gruel (ben-saalga) of functional interest in nutrition.

Lactic acid bacteria responsible for the fermentation of a pearl-millet based fermented gruel, ben-saalga, were investigated for enzyme activity in relation with the nutritional characteristics of gruels used as complementary foods for young children. Thirty pre-selected LAB from a set of 155 isolates were characterized principally for their ability to produce amylase, phytase and alpha-galactosidase. Two Lactobacillus plantarum strains (4.4 and 6.1) and three Lactobacillus fermentum strains (11.11.2, 3.7, 7.4) able to produce one or more of these enzymes were selected. Only weak amylase activity was found in the two Lactobacillus plantarum strains. alpha-amylase activity was associated with cells and was lower than 0.05 Ceralpha Units/ml. Phytase activity was detected in all five strains and was linked to the cell. The highest phytase activity was found in Lb. plantarum 4.4 and 6.1 (348.7 +/- 17.4U/ml and 276.3 +/- 51.4U/ml, respectively) and Lb. fermentum 7.4. (276.3 +/- 13.2U/ml). All strains displayed a cell-linked alpha-galactosidase activity. In a medium containing 2% glucose, the highest cellular activity was found in Lb. fermentum 3.7 (1441.1 +/- 133.7U/ml) and Lb. plantarum 4.4 (1223.1 +/- 148.3U/ml) after 6h of fermentation in the presence of stachyose, and in Lb. plantarum 4.4 (763.3 +/- 23.5U/ml) and Lb. fermentum 7.4 (346.7 +/- 14.8U/ml) after 24h of fermentation with raffinose. These results are consistent with previous observations showing that phytates and alpha-galactooligosaccharides decreased during the natural lactic acid fermentation of pearl millet slurries, and that partial starch hydrolysis can be performed by endogenous microflora provided a pre-gelatinisation step is included in the process.

Identification of Bacillus spp. from Bikalga, fermented seeds of Hibiscus sabdariffa: phenotypic and genotypic characterization.

AIMS: To identify Bacillus spp. responsible of the fermentation of Hibiscus sabdariffa for production of Bikalga, an alkaline fermented food used as a condiment in Burkina Faso. METHODS AND RESULTS: Seventy bacteria were isolated from Bikalga produced in different regions of Burkina Faso and identified by phenotyping and genotyping using PCR amplification of the 16S-23S rDNA intergenic transcribed spacer (ITS-PCR), repetitive sequence-based PCR (rep-PCR) and DNA sequencing. The isolates were characterized as motile, rod-shaped, endospore forming, catalase positive, Gram-positive bacteria. ITS-PCR allowed typing mainly at species level. Rep-PCR was more discriminative and allowed a typing at ssp. level. The DNA sequencing combined with the Blast search program and fermentation profiles using API 50CHB system allowed an identification of the bacteria as Bacillus subtilis, B. licheniformis, B. cereus, B. pumilus, B. badius, Brevibacillus bortelensis, B. sphaericus and B. fusiformis. B. subtilis were the predominant bacterium (42) followed by B. licheniformis (16). CONCLUSIONS: Various species and ssp. of Bacillus are involved in fermentation of H. sabdariffa for production of Bikalga. SIGNIFICANCE AND IMPACT OF THE STUDY: Selection of starter cultures of Bacillus for controlled production of Bikalga, selection of probiotic bacteria.

Technological properties of Lactobacillus fermentum involved in the processing of dolo and pito, West African sorghum beers, for the selection of starter cultures.

AIM: Technological properties of Lactobacillus fermentum isolates involved in spontaneous fermentation of dolo and pito wort were examined to select starter cultures. METHODS AND RESULTS: 264 isolates were screened for antimicrobial activity, acidifying activity, exopolysaccharides (EPSs) and amylase production. An antimicrobial activity was detected for 33.3%, 31.8%, 22.7% and 15.9% of the isolates towards Staphylococcus aureus enterotoxin A producer, Staphylococcus aureus enterotoxin A and B producer, Escherichia coli and Listeria innocua, respectively. A similarity was found between the isolates which were clustered in four groups according to their rates of acidification of sorghum malt broth. The faster acidifying group of isolates (43.48%) had a rate of acidification evaluated as Delta pH of 1.14 +/- 0.15 pH unit after 6 h of fermentation, followed by a second group of isolates (38.08%) with a similar rate of acidification after 9 h of fermentation. From the isolates endowed with an antimicrobial activity, 5.76% belonged to the faster acidifying group and 40.38% belonged to the second group. 88.7% of the isolates had the ability for producing EPSs but not amylase. CONCLUSION: Lactobacillus fermentum ferments dolo and pito wort by lowering the pH and providing organic acids, EPSs and antimicrobial compounds. SIGNIFICANCE AND IMPACT OF THE STUDY: Strains with a rapid rate of acidification, an antimicrobial activity and producing EPSs are suggested to have potential for starter cultures.

The biodiversity of predominant lactic acid bacteria in dolo and pito wort for the production of sorghum beer.

AIM: To quantify and identify the predominant lactic acid bacteria (LAB) in dolo and pito wort processing, and to examine their biodiversity at strain level. MATERIALS AND RESULTS: The processing of dolo and pito wort was studied at four production sites in Burkina Faso and Ghana. The succession of dominant micro-organisms, pH and titratable acidity were determined from sorghum malt through mashing and acidification to final wort. In the sorghum malt and during mashing, the LAB counts were 5.7-7.5 log CFU g(-1). Similar levels of yeasts and gram-negative, catalase-positive bacteria were observed. These levels decreased to 3.7-4.5 log CFU g(-1) and

Antimicrobial activity of Bacillus subtilis and Bacillus pumilus during the fermentation of African locust bean (Parkia biglobosa) for Soumbala production.

AIMS: To examine predominant isolates of Bacillus subtilis and B. pumilus isolated from Soumbala for their antimicrobial activity against indicator microorganisms as Micrococcus luteus, Staphyloccocus aureus, Bacillus cereus, Enterococus facium, Listeria monocytogenes, Escherichia coli, Salmonella typhimurium, Shigella dysenteriae, Yersinia enterocolitica, Aspergillus ochraceus and Penicillium roqueforti. METHODS AND RESULTS: Growth inhibition of indicator microorganisms by cells and supernatants of three B. subtilis and two B. pumilus strains was investigated using agar diffusion tests. Inactivation of indicator microorganisms was investigated in laboratory broth and during the fermentation of African locust bean for Soumbala production. The Bacillus isolates showed variable ability of inhibition and inactivation according to the indicator microorganism. The supernatants of pure cultures of B. subtilis inhibited one strain of B. cereus, one of Staph. aureus and E. coli and caused abnormal germination of Aspergillus ochraceus. The supernatant of mixed cultures of B. subtilis and indicators inhibited all the indicators. A treatment with protease eliminated the inhibitions. Isolates of B. subtilis inactivated all the indicators organisms during the fermentation of African locust bean as well as in laboratory broth with about five to eight decimal reduction. CONCLUSION: Bacillus isolates from Soumbala inhibit and inactivate Gram-positive and Gram-negative bacteria as well as ochratoxin A producing fungi during both laboratory cultivation and natural fermentation. SIGNIFICANCE AND IMPACT OF THE STUDY: Selection of starter cultures of Bacillus spp. for controlled production of Soumbala.

Volatile compounds of Soumbala, a fermented African locust bean (Parkia biglobosa) food condiment.

AIMS: To determine the profile of volatile compounds responsible for the aroma of Soumbala produced spontaneously and with pure and mixed cultures of Bacillus subtilis and Bacillus pumilus. METHODS AND RESULTS: Traditional and controlled fermentation trials of African locust bean with pure and mixed starter cultures of B. subtilis (B7, B9 and B15) and B. pumilus (B10) were performed. Aroma volatiles were analysed using Likens-Nikerson method coupled with gas chromatography and mass spectrophotometry. Sensory analysis of Soumbala as well as rice dishes prepared with each type of Soumbala were carried out by 10 panellists. In total 116 compounds were identified. They included pyrazines, aldehydes, ketones, esters, alcohols, acids, alkanes, alkenes, amines, pyridines, benzenes, phenols, sulphurs, furans and other compounds. Using principal component analysis for comparison, the aroma profiles of the Soumbala samples could be separated into three groups. The sensory evaluation showed variable acceptability. However, it was noticed that Soumbala samples produced with starter cultures were scored higher than traditionally prepared Soumbala. CONCLUSIONS: Aroma volatiles and organoleptic properties of Soumbala vary according to the Bacillus isolates involved in the fermentation. SIGNIFICANCE AND IMPACT OF THE STUDY: This study contributes to the selection of Bacillus starter cultures for controlled production of Soumbala.

Degradation of African locust bean oil by Bacillus subtilis and Bacillus pumilus isolated from soumbala, a fermented African locust bean condiment.

AIMS: To investigate predominant isolates of Bacillus subtilis and B. pumilus in soumbala, a fermented African locust bean condiment, for their ability to degrade African locust bean oil (ALBO). METHODS AND RESULTS: Agar diffusion test in tributyrin and ALBO agar was used for screening of the isolates for esterase and lipase activity, respectively. The quantity and the profile of free fatty acids (FFA) during 72 h of degradation of ALBO by the Bacillus isolates were studied by titration and gas chromatography. The degradation of tributyrin and ALBO was variable among the isolates. Two strains of B. subtilis and two strains of B. pumilus showed significantly higher esterase and lipolytic activities than the others. The degradation ALBO was most pronounced in enriched nutrient agar except for one isolate of B. pumilus degrading ALBO to the same extent regardless of the enrichment. The quantity of FFA released from ALBO by the most lipolytic strains of Bacillus increased mainly between 0 and 24 h and differed among the isolates. The profile of FFA was similar for the Bacillus isolates with oleic acid (C18:2) occurring as the major FFA in all the samples except in samples incubated with B. subtilis B9 where stearic acid (C18) was dominant. CONCLUSION: Bacillus isolates from soumbala showed high strain dependent lipolytic activity against ALBO. SIGNIFICANCE AND IMPACT OF THE STUDY: This study contributes to the selection of Bacillus strains to be used as starter cultures for controlled production of soumbala.

Degradation of proteins during the fermentation of African locust bean (Parkia biglobosa) by strains of Bacillus subtilis and Bacillus pumilus for production of Soumbala.

AIMS: To examine isolates of Bacillus subtilis and B. pumilus predominant in Soumbala for their ability to degrade African locust bean proteins (ALBP). METHODS AND RESULTS: Agar diffusion test in casein and ALBP agar was used for screening of isolates. The profiles of water-soluble proteins and free amino acids (FAA) during the fermentation of ALBP by the Bacillus isolates were studied by SDS-PAGE and cation exchange chromatography. The profile of soluble proteins changed with the fermentation time and varied depending on the isolate. The quantity of total FAA and essential FAA such as lysine was increased sharply between 24 and 48 h of fermentation and differed among the isolates. Simultaneously, a pH increase was observed. Cysteine, methionine, leucine, isoleucine, tyrosine and phenylalaline appeared during fermentation. CONCLUSION: The Bacillus isolates studied degraded ALBP leading to a profile of soluble proteins and FAA specific for each isolate. SIGNIFICANCE AND IMPACT OF THE STUDY: This study contributes to the selection of Bacillus strains to be used as starter cultures for controlled production of Soumbala.

Identification and characterization of Saccharomyces cerevisiae strains isolated from West African sorghum beer.

The occurrence and characterization of yeasts isolated from sorghum beer produced in Ghana and Burkina Faso, West Africa, were investigated. The yeasts involved in the fermentations were found to consist of Saccharomyces spp. almost exclusively. Of the isolates investigated, 45% were identified as Saccharomyces cerevisiae, whereas more than half of the isolates (53%) had physiological properties atypical of S. cerevisiae or any other member of the complex sensu strictu, as they were able to assimilate only glucose, maltose and ethanol as carbon sources. Both ITS-PCR RFLP and PFGE strongly indicated that these isolates were related to S. cerevisiae, regardless of their phenotypic characteristics. Sequencing of the D1/D2 domain of the 26S rDNA confirmed the close relatedness to S. cerevisiae with 0.5% nucleotide differences. The MAL1 and MAL3 loci were found for all isolates as the only recognized MAL loci. Besides, for 40% of the isolates the MAL61 probe hybridized to a position of about 950 kbp, which has not formerly been described as a MAL locus. The results showed that the spontaneous fermentation of West African sorghum beer is dominated by a variety of strains of S.cerevisiae not previously described, among which starter cultures should be selected.

[Evaluation of the Ivory Coast sentinel surveillance system for antimalarial drug sensitivity]. / Evaluation du systéme ivoirien de survelliance sentinelle de la chimosensibilité des antipaludiques.

This study was performed to assess the sentinel surveillance system on malaria resistance in Cote d'Ivoire using a new method. Evaluation was based on documentation describing routine products and on activity reports obtained from the surveillance system. A qualitative approach was used to assess system design and quantitative approach to assess its operation. Degree of satisfaction with evaluation criteria was scored on a scale of 1 to 5. Score reproducibility in this study was good. Overall the system was considered as satisfactory. The strong points of the system are relevance, functions, sustainability, and data quality. The weak points are poor planning, overcentralization, and underuse of information. Correction of these weakness will require concentration by all parties at the national level involved in the surveillance system. The evaluation method used was simple, cheap and reproducible and thus could serve as an alternative approach for evaluation of sentinel surveillance systems in areas with scarce resources.

Predicting the impact sensitivity of explosive molecules using neuromimetic networks.

A new method for predicting the impact sensitivity of explosive molecules is presented. This method makes use of a network of formal neurons. The experiment uses 124 molecules belonging to different families. The molecular descriptors taken into account are the molecule's oxygen balance and the enumeration of certain groups. The results obtained are satisfactory: 80% of the molecules are correctly classed on a scale of four sensitivities. Comparison with a multivariate linear regression analysis gives a slight advantage to the neural network method.

[The role of the healer in neuropsychiatric care in the Revolutionary People's Republic of Guinea]. / La place du guérisseur dans les soins neuropsychiatriques en République Populaire Révolutionnaire de Guinée.

These comments reflect some actuality in Guinea, country where healers are generally controlled for their activities in order to integrate them to the medical life of the country, at least for primary care. In neuropsychiatry, the healer is more mysterious and less precise in its activities. He uses for its treatment exogenous factors: suggestion, a privileged relationship with his patient, drug administration. The endogenous factors used are dream utilisation, mystical states, transes. The neuropsychiatric healer integrates very poorly in the medical society and he will certainly create a problem in the future, with the coming of modern psychiatry. He will have to be situated in face of this socio cultural evaluation in the approach to mental patients. Nothing is done in this field, neither at the level of WHO, nor at the level of the state of Guinea.