The objective of this work is to improve the physical and mechanical properties of stabilized earth blocks (BTC) used in construction in the Ndé department of Cameroon. To achieve this, two stabilizers, cement an...The objective of this work is to improve the physical and mechanical properties of stabilized earth blocks (BTC) used in construction in the Ndé department of Cameroon. To achieve this, two stabilizers, cement and sawdust, were used at varying percentages of 0%, 4%, 6%, and 8%. Physical characterization tests, including natural water content, specific weight, jar test, Protor, and Atterberg limits, were conducted. Additionally, mechanical tests, such as compression and three-point bending, were performed. The results show that as the amount of stabilizer increases, the density of BTC decreases. The samples with 8% sawdust have the highest density, while those without stabilizers have the lowest. Porosity decreases as sawdust and cement content increases, with smaller values observed in samples with 8% sawdust or cement. Our tests indicate that blocks stabilized with cement have slightly higher compressive strength than those stabilized with sawdust. However, the water absorption rate increases with higher sawdust content.展开更多
The production and consumption of avocado pears generates tons of wastes, mainly the pear peels which are usually discarded, although they have been reported to contain important phyto-chemicals with biological activi...The production and consumption of avocado pears generates tons of wastes, mainly the pear peels which are usually discarded, although they have been reported to contain important phyto-chemicals with biological activities. The adverse health effect associated with the consumption of saturated lipid based foods has ignited research on reformulation of lipid based foods to eliminate Trans Fatty Acids (TFAs). This study was thus aimed at the extraction and characterization of oil from Avocado Peels (APO) and evaluation of the quality of margarine produced from it. Five verities of pear were used for oil extraction by soxhlet method and physiochemical, oxidative, functional and antioxidant characterization was done. Margarines were formulated using a central composite design using oil blends of APO and Virgin Coconut Oil (VCO) with an oil ratio of 10:90, 40:60, 70:30 respectively, varied blending speed, blending time, and chitosan concentration. Samples were characterized and the effect of process parameters on the physiochemical and functional properties of the margarine studied. Optimized conditions were used to produce samples for sensory evaluation. Color, spreadability, aroma, taste and general acceptability was evaluated using ranking difference test. The results showed that the yield, density, and iodine values of APOs oils ranged from 14.91 ± 0.18 to 11.76 ± 0.46;0.93 ± 0.001 to 0.99 ± 0.1;46.63 ± 1.70 to 52.4 ± 0.63, their acid values, TBA and PV values ranged from 1.42 ± 0.39 to 1.97 ± 0.5;0.11 ± 0.002 to 0.18 ± 0.04;and 2.72 ± 0.14 to 4.43 ± 0.36 respectively, with Brogdon avocado peel variety having the overall best properties prepared blends of trans-free APO margarines showed that increase in APO ratio decreased melting point, increased oxidative stability and reduced moisture content of margarine samples. Chitosan addition leads to decrease moisture content and increase functional properties. VCO lead to increase in phenolic and flavonoid content of the margarines. Samples were spreadable a展开更多
Brewers’ spent grains constitute a nutrient-rich valuable and highly under-utilized by-product of the beer industry produced in large amounts all through the year. This bio-resource is a very good candidate for valor...Brewers’ spent grains constitute a nutrient-rich valuable and highly under-utilized by-product of the beer industry produced in large amounts all through the year. This bio-resource is a very good candidate for valorization, due to environmental and economic concerns, using biotechnological processing, particularly for food enrichment. This study was undertaken to evaluate the effect of fortification of Adakwa with traditional brewers’ spent grains (TBSG) on its physicochemical and nutritional properties as well as its acceptability using an experimental design. Four (4) samples of Adakwa were produced with TBSG incorporated rates of 0% (control sample), 10%, 20%, and 30% and evaluated. Using an experimental design, the effect of process parameters, including the TBSG incorporation rate, cooking time, and cooking temperatures on the physicochemical and nutritional properties of the Adakwa were evaluated while the 9-point hedonic scale was used to evaluate the sensory properties and its overall acceptability: carbohydrate, protein, crude fibre, cellulose, polyphenol, antioxidant activity (FRAP and DPPH). The water absorption activity values were 81.2 ± 0.04, 4.55 ± 0.05, 9.73 ± 0.23, 3.31 ± 0.05, 6.73 ± 0.23, 1.60 ± 0.09, 28.85 ± 0.8 and 117 ± 3.54 respectively for 0% TBSG (control);86.8 ± 0.01, 1.81± 0.20, 16.22 ± 0.16, 5.54 ± 0.69, 6.01 ± 0.16, 6.59 ± 0.03, 25.89 ± 0.94 and 475.0 ± 21.21 respectively for 30% TBSG. The sample with a high nutrient content was further produced using a central composite design and the factors studied were temperature and time, with responses, crude fiber, and FRAP content. The optimum production condition was: % TBSG: 47.06%;temperature: 123.17℃;Time: 30.34 mins. The sample with 47% TBSG had the best overall acceptability after sensory evaluation with sensory scores of: 5.45 ± 0.76, 7.9 ± 0.79, 8.0 ± 1.0, 7.10 ± 0.16, 8.5 ± 1.6, 7.6 ± 0.98 for color, taste, aroma, mouthfeel, texture and overall acceptability respectively. Thus TBSG can be used to improve 展开更多
Cardiovascular diseases are serious pathologies that affect an increasing number of people. Several preventive measures are generally used, including supplementing of oils in foods. Our objective was to compare the ef...Cardiovascular diseases are serious pathologies that affect an increasing number of people. Several preventive measures are generally used, including supplementing of oils in foods. Our objective was to compare the effects of Tetracarpidum conophorum oil (TC) and corn oil (CO) on serum lipid profiles of normal male rats. 42 Wistar rats were divided into 7 groups. Diets included TC oil (groups TC5, TC10 and TC20) and corn oil (groups CO5, CO10 and CO20) in proportions of 5%, 10% and 20%, with a control group (T). After 5 weeks of feeding, several parameters were measured during and after the study, including body weight, food intake and organ weights (kidney, liver and fat). Lipid profiles (total cholesterol, TG, HDL and LDL), glucose and protein levels were measured in the serum. The increase in body mass was inversely proportional to the amount of oil in the food. The decrease in body mass and adiposomatic index of group TC10 was significant (p < 0.05) compared with the other groups. The lowest glycaemia (64.17 ± 5.14 mg/dl) was noted with the diet containing 20% TC oil. A significant reduction in total cholesterol, LDL fraction and blood triglycerides was observed in the groups supplemented with TC and corn oils compared to controls. Results were also more beneficial for the TC10 group. HDL-cholesterol levels were significantly higher (p < 0.05) in the oil-supplemented groups than in the control group. Castelli’s risk indices decrease significantly (p < 0.05) with increasing oil content for TC. The oils had no impact on blood protein contents. One can conclude that a diet containing 10% crude oil from TC kernels could prevent or alleviate cardiovascular diseases and glycemia.展开更多
Boscia aqueous extract. senegalensis on hyperglycemia, hyperlipidemia and oxidative stress induced in rats. The aqueous extract was prepared from B. senegalensis seed powders under the extraction conditions: time (10 ...Boscia aqueous extract. senegalensis on hyperglycemia, hyperlipidemia and oxidative stress induced in rats. The aqueous extract was prepared from B. senegalensis seed powders under the extraction conditions: time (10 min), temperature (55˚C) and the ratio of mass of flour/volume of water (3/10 g/mL). Male wistar rats aged 6 to 8 weeks were acclimated and divided into 8 groups of 5 rats each: two normal control groups which received a normal standard diet (3810 kcal/kg), and six test groups which were subjected to a hyperlipidemic diet (5310 Kcal/kg). All groups of animals were fed in this manner for 8 weeks to induce hyperglycemia, hyperlipidemia and oxidative stress. After induction the animals were treated either with distilled water for the normal and negative control groups or with atorvastatin for the positive control group or with the extract of B. senegalensis. (125, 250 and 500 mg/kg) for the test groups. Fasting blood glucose was taken every 7 days during induction. After sacrifice, biochemical and oxidative stress parameters were measured. The aqueous extract of B. senegalensis significantly decreased (p B. senegalensis at a dose of 500 mg/kg has the capacity to reduce blood sugar, improve the quality of the lipid profile and reduce oxidative stress. Thus, the results reveal that the aqueous extract of B. senegalensis has powerful hypoglycemic, hypolipidemic and antioxidant properties.展开更多
Information about the type of gene action governing the inheritance of cowpea seed flavonoid content and antioxidant activity is prerequisite for starting an effective breeding program for developing improved varietie...Information about the type of gene action governing the inheritance of cowpea seed flavonoid content and antioxidant activity is prerequisite for starting an effective breeding program for developing improved varieties. For this purpose, half-diallel crosses among seven diverse parents were made. The homozygous parents and 21 F1 hybrids were evaluated at Maroua in the Sudano-Sahelian zone of Cameroon using a randomized complete block design with three replicates. Flour samples produced from decorticated seeds were used for biochemical analysis. Analysis of variance showed significant differences(P < 0.001) among genotypes for the studied traits with ranges of 363.6–453.9 mg rutin equivalent per 100 g dry weight(DW) for total flavonoids, 13.38–30.73 mg ascorbic acid equivalent per 1 g DW for ferric iron reducing activity, 70.98–266.93 mg trolox equivalent per 100 g DW for 2,2-diphenyl-1-picrylhydrazyl(DPPH) free radical scavenging activity, and 90.93–370.62 mg trolox equivalent per 100 g DW for 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS) free radical scavenging activity. Both additive and non-additive gene effects were significant in the genetic control of these traits, but dominance variance was greater than additive variance. The traits were mainly controlled by overdominance model suggesting a selection in the delayed generations.Broad- and narrow-sense heritability estimates varied from 0.90 to 0.99 and from 0.12 to 0.45,respectively. The variances due to both general and specific combining ability were highly significant for all studied traits. Recessive alleles had positive effects on DPPH and ABTS scavenging activities, whereas dominant alleles had positive effects on flavonoid content and ferric iron reducing activity. These results could help cowpea breeders to improve the antioxidant potential of cowpea seeds by appropriate selection.展开更多
During the years 2021 and 2022, the city of Maroua experienced repeated power blackouts. However, this locality has significant photovoltaic energy potential. Nevertheless, the evaluation of the electrical performance...During the years 2021 and 2022, the city of Maroua experienced repeated power blackouts. However, this locality has significant photovoltaic energy potential. Nevertheless, the evaluation of the electrical performance showed the dependence of the population on these fluctuations, which could be bypassed or suppressed. In most cases, the blackout occurs during high energy demand. In this paper, a method for evaluating electrical efficiency is proposed and its credibility has been demonstrated on the one hand, and on the other hand, a renewable energy production system is proposed. The Homer software has made possible the analysis of the proposed system and its impact on the environment has also been carried out. The techno-economic study of the system has proved that a solar photovoltaic farm associated with an energy storage system, with a capacity of 47 MW, can meet the energy demand of the town of Maroua. This alternative is profitable for this locality which lives in a precarious situation and a continuous need.展开更多
The project consists in the implementation of a biocomposite based on tannin resin and natural rubber matrices with the bast fibres of <i>Triumfetta cordifolia </i>A.Rich.“<i>Okong</i>” from ...The project consists in the implementation of a biocomposite based on tannin resin and natural rubber matrices with the bast fibres of <i>Triumfetta cordifolia </i>A.Rich.“<i>Okong</i>” from the equatorial region of Cameroon as reinforcement. A study of this still little known fibre is necessary. This paper evaluates the physico-chemical and mechanical characteristics of the fibers. The fibers are extracted by us. A series of experiments is conducted for this purpose: morphological observation with a scanning electron microscope (SEM);density evaluation with a helium pycnometer;absorption rate evaluation according to the protocol available in the literature, Fourier Transform Infrared Spectrometry (FT-IR), chemical composition evaluation according to ASTM 1972 and ASTM 1977 standards, thermogravimetric analysis (TGA) and tensile tests on fiber bundles according to NF T25-501-3. The results show that the fiber is made up of several elementary fibers with oval cross-sections. A density of 1.477g/cm<sup>3</sup> close to that of hemp. These fibers have a water absorption rate of 342.5%, which correlates with the presence of free hydroxyl functional groups obtained from the spectrometry study (FT-IR). Chemical analysis reveals that the fiber is made up of celluloses (44.4%), hemicelluloses (30.8%), lignins (18.9%), pectins (3.3%), waxes (0.5%) and minerals (2.1%). In addition, we learn that the fibers studied dehydrate at 11.49%, showinga notable thermal stability around 235°C with a peak thermal decomposition of cellulose located at 420°C. In terms of mechanical behaviour, the results reveal that the fibers offer a Young’s modulus in traction of 12.4 ± 6.9 GPa, a tensile strength of 526 ± 128 MPa and an elongation at break of 2.25%. The information thus obtained makes it possible to place these fibers in the same fiber group as flax and jute. They could therefore be used for the same types of applications. They also inform us that these fibers can withstand the temperatures of composite shaping by thermocom展开更多
<span style="font-family:Verdana;">In a context marked by the proliferation of smartphones and multimedia applications, the processing and transmission of images </span><span style="font-...<span style="font-family:Verdana;">In a context marked by the proliferation of smartphones and multimedia applications, the processing and transmission of images </span><span style="font-family:Verdana;">ha</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ve</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> become a real problem. Image compression </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">is</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"> the first approach to address this problem, it nevertheless suffers from its inability to adapt to the dynamics of limited environments, consisting mainly of mobile equipment and wireless networks. In this work, we propose a stochastic model to gradually estimate an image upon </span><span style="font-family:Verdana;">information</span><span style="font-family:Verdana;"> on its pixels that are transmitted progressively. We consider this transmission as a </span><span style="font-family:Verdana;">dynamical</span><span style="font-family:Verdana;"> process, where the sender </span><span style="font-family:Verdana;">push</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">es</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the data in decreasing significance order. In order to adapt to network conditions and performances, instead of truncating the pixels, we suggest a new method called Fast Reconstruction Method by Kalman Filtering (FRM-KF) consisting </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">of</span></span></span><span><span><span style="font-family:;" "=""><span style="fon展开更多
We consider general statistical models defined by moment equations when data are missing atrandom. Using the inverse probability weighting, such a model is shown to be equivalent with amodel for the observed variables...We consider general statistical models defined by moment equations when data are missing atrandom. Using the inverse probability weighting, such a model is shown to be equivalent with amodel for the observed variables only, augmented by a moment condition defined by the missing mechanism. Our framework covers a large class of parametric and semiparametric modelswhere we allow for missing responses, missing covariates and any combination of them. Theequivalence result is stated under minimal technical conditions and sheds new light on variousaspects of interest in the missing data literature, as for instance the efficiency bounds and theconstruction of the efficient estimators, the restricted estimators and the imputation.展开更多
The content of soluble sugar in cowpea(Vigna unguiculata L. Walp.) seeds is important for their acceptability to consumers. The objective of this study was to evaluate the genetic control of soluble sugar content in c...The content of soluble sugar in cowpea(Vigna unguiculata L. Walp.) seeds is important for their acceptability to consumers. The objective of this study was to evaluate the genetic control of soluble sugar content in cowpea using diallel analysis. For this purpose,half-diallel crosses were made among seven diverse parents. The amount of total soluble sugar was estimated by the phenol sulfuric acid reagent method and reducing sugar were measured by the DNS(3,5-dinitrosalicylic acid) reagent method. The total soluble sugar ranged from 11.12(VYA) to 40.79 mg g^(-1)(IT93 K-693-2) with a mean of 22.31 mg g^(-1).Reducing soluble sugar showed a mean value of 9.11 mg g^(-1) and ranged from 13.61(TVx3236) to 4.98 mg g^(-1)(Lori niebe). Diallel analysis showed that both additive and non-additive gene effects were significant in the genetic control of these traits. However,dominance variance was greater than additive variance for soluble sugar. The traits were controlled mainly by an overdominance model, suggesting the advantage of delaying selection to later generations. Soluble sugar content was found to be highly heritable, with broad-sense heritability ranging from 0.987 to 0.976. Narrow-sense heritability ranged from0.154 to 0.422 and revealed the lower importance of additive variance. Parents and F_1 hybrids differed significantly on the basis of their general and specific combining abilities,respectively. Recessive alleles had positive effects on total soluble sugar and reducing soluble sugar. These results could help cowpea breeders improve the acceptability of cowpea seeds and cowpea-based foods by appropriate selection.展开更多
In this paper, we present a new robust hybrid algorithm combining successively chaotic encryption and blind watermarking of images based on the quaternionic wavelet transform (QWT) to ensure the secure transfer of dig...In this paper, we present a new robust hybrid algorithm combining successively chaotic encryption and blind watermarking of images based on the quaternionic wavelet transform (QWT) to ensure the secure transfer of digital data. The calculations of the different evaluation parameters have been performed in order to determine the robustness of our algorithm to certain attacks. The application of this hybrid algorithm on CFA (Color Filter Array) images, allowed us to guarantee the integrity of the digital data and to propose an autonomous transmission system. The results obtained after simulation of this successive hybrid algorithm of chaotic encryption and then blind watermarking are appreciated through the values of the evaluation parameters which are the peak signal-to-noise ratio (PSNR) and the correlation coefficient (CC), and by the visual observation of the extracted watermarks before and after attacks. The values of these parameters show that this successive hybrid algorithm is robust against some conventional attacks.展开更多
Maintenance of glycemic control is important in preventing diabetes and its associated complications. Considering the current recommended approach for the use of functional foods and their bioactive components in the ...Maintenance of glycemic control is important in preventing diabetes and its associated complications. Considering the current recommended approach for the use of functional foods and their bioactive components in the prevention and management of diabetes, the aim of this study was to determine the antihyperglycemic effect of Moringa oleifera functional tea in rat models and in normoglycemic human volunteers using the oral glucose tolerance test (OGTT). Moringa tea prepared by extracting Moringa leaf powder in distilled water (1:20 mg/ml) at 97°C for 30 min was administered at different doses to male Wistar rats and human volunteers prior to glucose loading. Blood glucose was measured at intervals of 30 min for 150 min. Consumption of Moringa tea prior to glucose loading suppressed the elevation in blood glucose in all cases compared to controls that did not receive the tea initially. The degree and pattern of decrease however, were dose dependent. In rats, intermediate doses of 20 ml/kg BW were more effective in reducing blood glucose overall (18.2%) vs 13.3% and 6% at doses of 10 and 30 ml/kg BW respectively. In humans, the final decrease in blood glucose was not significantly different for high 400 ml (19%) and low 200 ml (17%) doses. Of interest here was the pattern of decrease, being significantly higher (p < 0.05) at 30 min with 200 ml (22.8%) than with 400 ml (17.9%). It is suggested that low doses exert their antihyperglycemic effect more at intestinal level by inhibiting glucose absorption, whereas high doses exert their effect more in circulation. We conclude that Moringa oleifera tea has potential as a functional food in the management of hyperglycemia.展开更多
Computer grids are infrastructures in which heterogeneous and distributed resources offer very high computing or storage performance. If they offer extreme computing performance, they are also subject to the appearanc...Computer grids are infrastructures in which heterogeneous and distributed resources offer very high computing or storage performance. If they offer extreme computing performance, they are also subject to the appearance of many failures related to this type of architecture. While performing tasks, if the response time of a node in the system incomprehensibly exceeds the requirements of the specifications, the node experiences an omission failure. The task running in the failed node will be unavailable until the node resumes normal activity. Waiting not being a possible solution, many fault tolerance methods have been proposed. Despite this large number of fault tolerance methods on offer, computer grids are still prone to many failures by omission. In this work, a numerical study of the failures by omission which occur in the calculation grids during the execution of the tasks was carried out and a model allowing anticipating its failures was proposed with the formalism PDEVS (Parallel Discret EVent system Specification).展开更多
Mulberry(Morus alba L.)leaf extract is well-known for its health-promoting features.However,food processing conditions affect its bioactive profile,which could be limited by encapsulation.Nevertheless,assessing the im...Mulberry(Morus alba L.)leaf extract is well-known for its health-promoting features.However,food processing conditions affect its bioactive profile,which could be limited by encapsulation.Nevertheless,assessing the impact of encapsulating techniques on the digestibility of embedded biocompounds requires further knowledge.Hence,the aimed of this study was to assess the effects of carrier materials and drying techniques on(i)bioaccessibility and bioavailability indexes,(ii)stability of nutraceuticals,and(iii)changes in antioxidant activities of mulberry leaf extract powder by using an in vitro oral-gastrointestinal digestion.Digestion was performed out at 37°C in darkness by shaking encapsulated extract with human saliva during 2 min,followed by 2 h of incubation with a pepsin-HCl mixture,then mixed for 2 h with bile salts and pancreatin.After digestion the samples were acidified and HPLC assayed.A significant(p<0.05)decrease in nutraceuticals content was noted during the intestinal phase with more reduction in gamma-aminobutyric acid(34.91–51.14%)compared to that of flavonols(16.58–28.90%),1-deoxynojirimycin(17.56–20.42%)and phenolic acids(0.53–0.67%)in the gastric digesta.Although encapsulation was observed to enhance the bioaccessibility,negative effects were found in terms of the bioefficiency and bioavailability.Furthermore,encapsulation techniques mostly affected the ion reducing capacity than the radical scavenging capacity.The outcomes suggested that carriers had a major effect on the digestibility and antioxidative activity,whilst the drying techniques mostly affect the bioaccessibility and bioavailability of the flavonols.展开更多
A growing number of international studies have highlighted that ambient air pollution exposures are related to different health outcomes. To do so, researchers need to estimate exposure levels to air pollution through...A growing number of international studies have highlighted that ambient air pollution exposures are related to different health outcomes. To do so, researchers need to estimate exposure levels to air pollution throughout everyday life. In the literature, the most commonly used estimate is based on home address only or taking into account, in addition, the work address. However, several studies have shown the importance of daily mobility in the estimate of exposure to air pollutants. In this context, we developed an R procedure that estimates individual exposures combining home addresses, several important places, and itineraries of the principal mobility during a week. It supplies researchers a useful tool to calculate individual daily exposition to air pollutants weighting by the time spent at each of the most frequented locations (work, shopping, residential address, etc.) and while commuting. This task requires the efficient calculation of travel time matrices or the examination of multimodal transport routes. This procedure is freely available from the Equit’Area project website: (https://www.equitarea.org). This procedure is structured in three parts: the first part is to create a network, the second allows to estimate main itineraries of the daily mobility and the last one tries to reconstitute the level of air pollution exposure. One main advantage of the tool is that the procedure can be used with different spatial scales and for any air pollutant.展开更多
In African communities, traditional beer drinking remains a unifying factor within its populations both socially, commercially, culturally, politically, in health and nutrition and for some ritual practices. In this r...In African communities, traditional beer drinking remains a unifying factor within its populations both socially, commercially, culturally, politically, in health and nutrition and for some ritual practices. In this research a field survey was carried out to investigate the consumption of corn beer and in particular <i>Nkang</i> in the North-West Region of Cameroon. The tools that were employed to carry out these investigations included face-to-face interviews and the use of properly designed questionnaires. Results from the survey showed that three types of maize-based beverages are drunk in the North-West Region of Cameroon, which are locally called <i>Kwacha</i> (whitish, most viscous and most turbid), <i>Sha-ah</i> (cream white, viscous and turbid) and <i>Nkang</i> (dark brown, least viscous and least turbid) in terms of colour, viscosity and turbidity. The percentage awareness of the existence of these beers from the sampled population gave the following values;60.9% for <i>Kwacha</i>, 100% for <i>Sha-ah</i> and 89.1% for <i>Nkang</i>. Nonetheless, 54.5% of the 60.9% of those who were aware of the existence of <i>kwacha</i> had at least tasted it. Also 98.2% out of the 100% for <i>Sha-ah</i> and 85.5% out of 89.1% for <i>Nkang</i> had tasted them, too. <i>Nkang</i> was found to be the most preferred to <i>Sha-ah</i> then <i>Kwacha</i> in that order by the consumers since <i>Nkang</i> is very tasteful, least alcoholic, least turbid, least viscous, has the most attractive colour than the others, has a significant impact on the culture of some localities in this region and as well as it is natural and nutritious. However, <i>Nkang</i> as well as the other two has varying organoleptic properties, unsatisfactory conservation and short shelf-life. Hence are consumed within a short period of time from their production. Because of the low alcoholic content of <i>Nkang</i>, the beverage is consumed by both adults (most elderly), children, those who have health problems and it is mostly preferred by some Christians th展开更多
Bio-glycerol was synthesized from Cameroon palm kernel oil (PKO) through the transesterification procedure. Palm kernel oil extracted from palm kernel seeds using mechanical expression and solvent extraction was purif...Bio-glycerol was synthesized from Cameroon palm kernel oil (PKO) through the transesterification procedure. Palm kernel oil extracted from palm kernel seeds using mechanical expression and solvent extraction was purified and characterized by physico-chemical methods and used in the transesterification process to give biodiesel and bio-glycerol. The biodiesel was purified and characterized as reported in previous articles. Our focus in this article is on glycerol, an important by-product of the transesterification process which has potential pharmaceutical, cosmetic and engineering applications. The bio-glycerol was purified by acidification and the purified glycerol was subjected to physical and chemical characterization. The specific gravity of glycerol was obtained as 1.2 kg/L, viscosity at 40°C gave 1500 cSt and 500 cSt at 100°C;pH was 7.4;the flash point was 160°C, and the ASTM color was 2.0 before purification and zero after purification. The sulfur content was 0.016%w/v. This sulfur content is low thus posing no environment threat. The chemical composition of the synthesized bio-glycerol determined using IR spectroscopy and gas chromatography-mass spectrometry (GC-MS) confirmed the known chemical structure of glycerol. The purification and analysis of bio-glycerol is important as it can find applications in the pharmaceutical, cosmetic and food industries inter alia.展开更多
Particle size fractionation by sieving is used to optimize antioxydant potential of natural substances. The aim of the present study was to evaluate particle size effects on antioxidant and hepatoprotective potential ...Particle size fractionation by sieving is used to optimize antioxydant potential of natural substances. The aim of the present study was to evaluate particle size effects on antioxidant and hepatoprotective potential of Eucalyptus camaldulensis essential oils (EO) on CCl<sub>4</sub>-induced hepatic damage in Wistar rats. Animals were daily orally treated with the EOs extracted by hydrodistillation from powder sieved at four particle sizes (≥355, 200 - 355, 100 - 200, ≤100 μm) and those of the unsieved powder at dose of 50 mg/Kg for 7 days. Compounds that are evaluated for these activities are hydrocarbons and oxygenated terpenes that were identified and quantified by GC/MS. Activities of enzymes markers of hepatocellular damage in serum and antioxidant enzymes in the liver homogenates were measured. In this research, EOs significantly prevented the increase in serum ALT and AST (p < 0.05), total cholesterol, triglyceride and LDL-cholesterol level in acute liver damage induced by CCl<sub>4</sub> and significant increase level of plasma HDL-cholesterol. Also, significantly (p < 0.05) decreased the extent of malondialdehyde (MDA) formation and elevated the activities of superoxide dismutase (SOD) and catalase (CAT) liver in comparison to negative control group. The best antioxidant and hepatoprotective activities were those of EOs from two fine powder fractions (≤100 μm and 100 - 200 μm) was correlated to their high concentration in oxygenated terpenes (70.9% and 46.4%, respectively), when compared to the large particles (200 - 355 μm and ≥355 μm, with 33.3% and 41.8%, respectively) and unsieved powder (37.4%).展开更多
Moringa oleifera leaves are an important source of dietary phytochemicals,such as flavonoids with high antioxidant activity(AOA).These components are however influenced by the post-harvest treatments applied as well a...Moringa oleifera leaves are an important source of dietary phytochemicals,such as flavonoids with high antioxidant activity(AOA).These components are however influenced by the post-harvest treatments applied as well as the processing conditions.Hence,it is crucial to determine the most appropriate post-harvest treatment that preserves or enhances AOA.To this effect the influence of steam blanching,fermentation/oxidation,oven drying and roasting of fresh Moringa leaves on their AOA was investigated.Processing conditions of time and temperature for each treatment were optimised using response surface methodology.The effect of the different treatments at optimal conditions on phenolic profile and AOA were compared.Roasting achieved the most significant(p<0.05)improvement in phenolics(43%)and AOA(22–31%),which was accompanied by the formation of 2 new compounds,quercetin-3-O-acetylglucoside and Quercetine-3-O-rhamnoside.Steam blanching had the most deleterious effect on phenolics(-31%)and AOA.Post-harvest treatments qualitatively and quantitatively affect phytochemical profile of Moringa leaves.展开更多
文摘The objective of this work is to improve the physical and mechanical properties of stabilized earth blocks (BTC) used in construction in the Ndé department of Cameroon. To achieve this, two stabilizers, cement and sawdust, were used at varying percentages of 0%, 4%, 6%, and 8%. Physical characterization tests, including natural water content, specific weight, jar test, Protor, and Atterberg limits, were conducted. Additionally, mechanical tests, such as compression and three-point bending, were performed. The results show that as the amount of stabilizer increases, the density of BTC decreases. The samples with 8% sawdust have the highest density, while those without stabilizers have the lowest. Porosity decreases as sawdust and cement content increases, with smaller values observed in samples with 8% sawdust or cement. Our tests indicate that blocks stabilized with cement have slightly higher compressive strength than those stabilized with sawdust. However, the water absorption rate increases with higher sawdust content.
文摘The production and consumption of avocado pears generates tons of wastes, mainly the pear peels which are usually discarded, although they have been reported to contain important phyto-chemicals with biological activities. The adverse health effect associated with the consumption of saturated lipid based foods has ignited research on reformulation of lipid based foods to eliminate Trans Fatty Acids (TFAs). This study was thus aimed at the extraction and characterization of oil from Avocado Peels (APO) and evaluation of the quality of margarine produced from it. Five verities of pear were used for oil extraction by soxhlet method and physiochemical, oxidative, functional and antioxidant characterization was done. Margarines were formulated using a central composite design using oil blends of APO and Virgin Coconut Oil (VCO) with an oil ratio of 10:90, 40:60, 70:30 respectively, varied blending speed, blending time, and chitosan concentration. Samples were characterized and the effect of process parameters on the physiochemical and functional properties of the margarine studied. Optimized conditions were used to produce samples for sensory evaluation. Color, spreadability, aroma, taste and general acceptability was evaluated using ranking difference test. The results showed that the yield, density, and iodine values of APOs oils ranged from 14.91 ± 0.18 to 11.76 ± 0.46;0.93 ± 0.001 to 0.99 ± 0.1;46.63 ± 1.70 to 52.4 ± 0.63, their acid values, TBA and PV values ranged from 1.42 ± 0.39 to 1.97 ± 0.5;0.11 ± 0.002 to 0.18 ± 0.04;and 2.72 ± 0.14 to 4.43 ± 0.36 respectively, with Brogdon avocado peel variety having the overall best properties prepared blends of trans-free APO margarines showed that increase in APO ratio decreased melting point, increased oxidative stability and reduced moisture content of margarine samples. Chitosan addition leads to decrease moisture content and increase functional properties. VCO lead to increase in phenolic and flavonoid content of the margarines. Samples were spreadable a
文摘Brewers’ spent grains constitute a nutrient-rich valuable and highly under-utilized by-product of the beer industry produced in large amounts all through the year. This bio-resource is a very good candidate for valorization, due to environmental and economic concerns, using biotechnological processing, particularly for food enrichment. This study was undertaken to evaluate the effect of fortification of Adakwa with traditional brewers’ spent grains (TBSG) on its physicochemical and nutritional properties as well as its acceptability using an experimental design. Four (4) samples of Adakwa were produced with TBSG incorporated rates of 0% (control sample), 10%, 20%, and 30% and evaluated. Using an experimental design, the effect of process parameters, including the TBSG incorporation rate, cooking time, and cooking temperatures on the physicochemical and nutritional properties of the Adakwa were evaluated while the 9-point hedonic scale was used to evaluate the sensory properties and its overall acceptability: carbohydrate, protein, crude fibre, cellulose, polyphenol, antioxidant activity (FRAP and DPPH). The water absorption activity values were 81.2 ± 0.04, 4.55 ± 0.05, 9.73 ± 0.23, 3.31 ± 0.05, 6.73 ± 0.23, 1.60 ± 0.09, 28.85 ± 0.8 and 117 ± 3.54 respectively for 0% TBSG (control);86.8 ± 0.01, 1.81± 0.20, 16.22 ± 0.16, 5.54 ± 0.69, 6.01 ± 0.16, 6.59 ± 0.03, 25.89 ± 0.94 and 475.0 ± 21.21 respectively for 30% TBSG. The sample with a high nutrient content was further produced using a central composite design and the factors studied were temperature and time, with responses, crude fiber, and FRAP content. The optimum production condition was: % TBSG: 47.06%;temperature: 123.17℃;Time: 30.34 mins. The sample with 47% TBSG had the best overall acceptability after sensory evaluation with sensory scores of: 5.45 ± 0.76, 7.9 ± 0.79, 8.0 ± 1.0, 7.10 ± 0.16, 8.5 ± 1.6, 7.6 ± 0.98 for color, taste, aroma, mouthfeel, texture and overall acceptability respectively. Thus TBSG can be used to improve
文摘Cardiovascular diseases are serious pathologies that affect an increasing number of people. Several preventive measures are generally used, including supplementing of oils in foods. Our objective was to compare the effects of Tetracarpidum conophorum oil (TC) and corn oil (CO) on serum lipid profiles of normal male rats. 42 Wistar rats were divided into 7 groups. Diets included TC oil (groups TC5, TC10 and TC20) and corn oil (groups CO5, CO10 and CO20) in proportions of 5%, 10% and 20%, with a control group (T). After 5 weeks of feeding, several parameters were measured during and after the study, including body weight, food intake and organ weights (kidney, liver and fat). Lipid profiles (total cholesterol, TG, HDL and LDL), glucose and protein levels were measured in the serum. The increase in body mass was inversely proportional to the amount of oil in the food. The decrease in body mass and adiposomatic index of group TC10 was significant (p < 0.05) compared with the other groups. The lowest glycaemia (64.17 ± 5.14 mg/dl) was noted with the diet containing 20% TC oil. A significant reduction in total cholesterol, LDL fraction and blood triglycerides was observed in the groups supplemented with TC and corn oils compared to controls. Results were also more beneficial for the TC10 group. HDL-cholesterol levels were significantly higher (p < 0.05) in the oil-supplemented groups than in the control group. Castelli’s risk indices decrease significantly (p < 0.05) with increasing oil content for TC. The oils had no impact on blood protein contents. One can conclude that a diet containing 10% crude oil from TC kernels could prevent or alleviate cardiovascular diseases and glycemia.
文摘Boscia aqueous extract. senegalensis on hyperglycemia, hyperlipidemia and oxidative stress induced in rats. The aqueous extract was prepared from B. senegalensis seed powders under the extraction conditions: time (10 min), temperature (55˚C) and the ratio of mass of flour/volume of water (3/10 g/mL). Male wistar rats aged 6 to 8 weeks were acclimated and divided into 8 groups of 5 rats each: two normal control groups which received a normal standard diet (3810 kcal/kg), and six test groups which were subjected to a hyperlipidemic diet (5310 Kcal/kg). All groups of animals were fed in this manner for 8 weeks to induce hyperglycemia, hyperlipidemia and oxidative stress. After induction the animals were treated either with distilled water for the normal and negative control groups or with atorvastatin for the positive control group or with the extract of B. senegalensis. (125, 250 and 500 mg/kg) for the test groups. Fasting blood glucose was taken every 7 days during induction. After sacrifice, biochemical and oxidative stress parameters were measured. The aqueous extract of B. senegalensis significantly decreased (p B. senegalensis at a dose of 500 mg/kg has the capacity to reduce blood sugar, improve the quality of the lipid profile and reduce oxidative stress. Thus, the results reveal that the aqueous extract of B. senegalensis has powerful hypoglycemic, hypolipidemic and antioxidant properties.
基金supported in part by funds from the International Foundation for Science (IFS) (agreement number C/5262-1)
文摘Information about the type of gene action governing the inheritance of cowpea seed flavonoid content and antioxidant activity is prerequisite for starting an effective breeding program for developing improved varieties. For this purpose, half-diallel crosses among seven diverse parents were made. The homozygous parents and 21 F1 hybrids were evaluated at Maroua in the Sudano-Sahelian zone of Cameroon using a randomized complete block design with three replicates. Flour samples produced from decorticated seeds were used for biochemical analysis. Analysis of variance showed significant differences(P < 0.001) among genotypes for the studied traits with ranges of 363.6–453.9 mg rutin equivalent per 100 g dry weight(DW) for total flavonoids, 13.38–30.73 mg ascorbic acid equivalent per 1 g DW for ferric iron reducing activity, 70.98–266.93 mg trolox equivalent per 100 g DW for 2,2-diphenyl-1-picrylhydrazyl(DPPH) free radical scavenging activity, and 90.93–370.62 mg trolox equivalent per 100 g DW for 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS) free radical scavenging activity. Both additive and non-additive gene effects were significant in the genetic control of these traits, but dominance variance was greater than additive variance. The traits were mainly controlled by overdominance model suggesting a selection in the delayed generations.Broad- and narrow-sense heritability estimates varied from 0.90 to 0.99 and from 0.12 to 0.45,respectively. The variances due to both general and specific combining ability were highly significant for all studied traits. Recessive alleles had positive effects on DPPH and ABTS scavenging activities, whereas dominant alleles had positive effects on flavonoid content and ferric iron reducing activity. These results could help cowpea breeders to improve the antioxidant potential of cowpea seeds by appropriate selection.
文摘During the years 2021 and 2022, the city of Maroua experienced repeated power blackouts. However, this locality has significant photovoltaic energy potential. Nevertheless, the evaluation of the electrical performance showed the dependence of the population on these fluctuations, which could be bypassed or suppressed. In most cases, the blackout occurs during high energy demand. In this paper, a method for evaluating electrical efficiency is proposed and its credibility has been demonstrated on the one hand, and on the other hand, a renewable energy production system is proposed. The Homer software has made possible the analysis of the proposed system and its impact on the environment has also been carried out. The techno-economic study of the system has proved that a solar photovoltaic farm associated with an energy storage system, with a capacity of 47 MW, can meet the energy demand of the town of Maroua. This alternative is profitable for this locality which lives in a precarious situation and a continuous need.
文摘The project consists in the implementation of a biocomposite based on tannin resin and natural rubber matrices with the bast fibres of <i>Triumfetta cordifolia </i>A.Rich.“<i>Okong</i>” from the equatorial region of Cameroon as reinforcement. A study of this still little known fibre is necessary. This paper evaluates the physico-chemical and mechanical characteristics of the fibers. The fibers are extracted by us. A series of experiments is conducted for this purpose: morphological observation with a scanning electron microscope (SEM);density evaluation with a helium pycnometer;absorption rate evaluation according to the protocol available in the literature, Fourier Transform Infrared Spectrometry (FT-IR), chemical composition evaluation according to ASTM 1972 and ASTM 1977 standards, thermogravimetric analysis (TGA) and tensile tests on fiber bundles according to NF T25-501-3. The results show that the fiber is made up of several elementary fibers with oval cross-sections. A density of 1.477g/cm<sup>3</sup> close to that of hemp. These fibers have a water absorption rate of 342.5%, which correlates with the presence of free hydroxyl functional groups obtained from the spectrometry study (FT-IR). Chemical analysis reveals that the fiber is made up of celluloses (44.4%), hemicelluloses (30.8%), lignins (18.9%), pectins (3.3%), waxes (0.5%) and minerals (2.1%). In addition, we learn that the fibers studied dehydrate at 11.49%, showinga notable thermal stability around 235°C with a peak thermal decomposition of cellulose located at 420°C. In terms of mechanical behaviour, the results reveal that the fibers offer a Young’s modulus in traction of 12.4 ± 6.9 GPa, a tensile strength of 526 ± 128 MPa and an elongation at break of 2.25%. The information thus obtained makes it possible to place these fibers in the same fiber group as flax and jute. They could therefore be used for the same types of applications. They also inform us that these fibers can withstand the temperatures of composite shaping by thermocom
文摘<span style="font-family:Verdana;">In a context marked by the proliferation of smartphones and multimedia applications, the processing and transmission of images </span><span style="font-family:Verdana;">ha</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ve</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> become a real problem. Image compression </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">is</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"> the first approach to address this problem, it nevertheless suffers from its inability to adapt to the dynamics of limited environments, consisting mainly of mobile equipment and wireless networks. In this work, we propose a stochastic model to gradually estimate an image upon </span><span style="font-family:Verdana;">information</span><span style="font-family:Verdana;"> on its pixels that are transmitted progressively. We consider this transmission as a </span><span style="font-family:Verdana;">dynamical</span><span style="font-family:Verdana;"> process, where the sender </span><span style="font-family:Verdana;">push</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">es</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the data in decreasing significance order. In order to adapt to network conditions and performances, instead of truncating the pixels, we suggest a new method called Fast Reconstruction Method by Kalman Filtering (FRM-KF) consisting </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">of</span></span></span><span><span><span style="font-family:;" "=""><span style="fon
文摘We consider general statistical models defined by moment equations when data are missing atrandom. Using the inverse probability weighting, such a model is shown to be equivalent with amodel for the observed variables only, augmented by a moment condition defined by the missing mechanism. Our framework covers a large class of parametric and semiparametric modelswhere we allow for missing responses, missing covariates and any combination of them. Theequivalence result is stated under minimal technical conditions and sheds new light on variousaspects of interest in the missing data literature, as for instance the efficiency bounds and theconstruction of the efficient estimators, the restricted estimators and the imputation.
基金supported in part by funds from International Foundation for Science(C/5262-1)
文摘The content of soluble sugar in cowpea(Vigna unguiculata L. Walp.) seeds is important for their acceptability to consumers. The objective of this study was to evaluate the genetic control of soluble sugar content in cowpea using diallel analysis. For this purpose,half-diallel crosses were made among seven diverse parents. The amount of total soluble sugar was estimated by the phenol sulfuric acid reagent method and reducing sugar were measured by the DNS(3,5-dinitrosalicylic acid) reagent method. The total soluble sugar ranged from 11.12(VYA) to 40.79 mg g^(-1)(IT93 K-693-2) with a mean of 22.31 mg g^(-1).Reducing soluble sugar showed a mean value of 9.11 mg g^(-1) and ranged from 13.61(TVx3236) to 4.98 mg g^(-1)(Lori niebe). Diallel analysis showed that both additive and non-additive gene effects were significant in the genetic control of these traits. However,dominance variance was greater than additive variance for soluble sugar. The traits were controlled mainly by an overdominance model, suggesting the advantage of delaying selection to later generations. Soluble sugar content was found to be highly heritable, with broad-sense heritability ranging from 0.987 to 0.976. Narrow-sense heritability ranged from0.154 to 0.422 and revealed the lower importance of additive variance. Parents and F_1 hybrids differed significantly on the basis of their general and specific combining abilities,respectively. Recessive alleles had positive effects on total soluble sugar and reducing soluble sugar. These results could help cowpea breeders improve the acceptability of cowpea seeds and cowpea-based foods by appropriate selection.
文摘In this paper, we present a new robust hybrid algorithm combining successively chaotic encryption and blind watermarking of images based on the quaternionic wavelet transform (QWT) to ensure the secure transfer of digital data. The calculations of the different evaluation parameters have been performed in order to determine the robustness of our algorithm to certain attacks. The application of this hybrid algorithm on CFA (Color Filter Array) images, allowed us to guarantee the integrity of the digital data and to propose an autonomous transmission system. The results obtained after simulation of this successive hybrid algorithm of chaotic encryption and then blind watermarking are appreciated through the values of the evaluation parameters which are the peak signal-to-noise ratio (PSNR) and the correlation coefficient (CC), and by the visual observation of the extracted watermarks before and after attacks. The values of these parameters show that this successive hybrid algorithm is robust against some conventional attacks.
文摘Maintenance of glycemic control is important in preventing diabetes and its associated complications. Considering the current recommended approach for the use of functional foods and their bioactive components in the prevention and management of diabetes, the aim of this study was to determine the antihyperglycemic effect of Moringa oleifera functional tea in rat models and in normoglycemic human volunteers using the oral glucose tolerance test (OGTT). Moringa tea prepared by extracting Moringa leaf powder in distilled water (1:20 mg/ml) at 97°C for 30 min was administered at different doses to male Wistar rats and human volunteers prior to glucose loading. Blood glucose was measured at intervals of 30 min for 150 min. Consumption of Moringa tea prior to glucose loading suppressed the elevation in blood glucose in all cases compared to controls that did not receive the tea initially. The degree and pattern of decrease however, were dose dependent. In rats, intermediate doses of 20 ml/kg BW were more effective in reducing blood glucose overall (18.2%) vs 13.3% and 6% at doses of 10 and 30 ml/kg BW respectively. In humans, the final decrease in blood glucose was not significantly different for high 400 ml (19%) and low 200 ml (17%) doses. Of interest here was the pattern of decrease, being significantly higher (p < 0.05) at 30 min with 200 ml (22.8%) than with 400 ml (17.9%). It is suggested that low doses exert their antihyperglycemic effect more at intestinal level by inhibiting glucose absorption, whereas high doses exert their effect more in circulation. We conclude that Moringa oleifera tea has potential as a functional food in the management of hyperglycemia.
文摘Computer grids are infrastructures in which heterogeneous and distributed resources offer very high computing or storage performance. If they offer extreme computing performance, they are also subject to the appearance of many failures related to this type of architecture. While performing tasks, if the response time of a node in the system incomprehensibly exceeds the requirements of the specifications, the node experiences an omission failure. The task running in the failed node will be unavailable until the node resumes normal activity. Waiting not being a possible solution, many fault tolerance methods have been proposed. Despite this large number of fault tolerance methods on offer, computer grids are still prone to many failures by omission. In this work, a numerical study of the failures by omission which occur in the calculation grids during the execution of the tasks was carried out and a model allowing anticipating its failures was proposed with the formalism PDEVS (Parallel Discret EVent system Specification).
文摘Mulberry(Morus alba L.)leaf extract is well-known for its health-promoting features.However,food processing conditions affect its bioactive profile,which could be limited by encapsulation.Nevertheless,assessing the impact of encapsulating techniques on the digestibility of embedded biocompounds requires further knowledge.Hence,the aimed of this study was to assess the effects of carrier materials and drying techniques on(i)bioaccessibility and bioavailability indexes,(ii)stability of nutraceuticals,and(iii)changes in antioxidant activities of mulberry leaf extract powder by using an in vitro oral-gastrointestinal digestion.Digestion was performed out at 37°C in darkness by shaking encapsulated extract with human saliva during 2 min,followed by 2 h of incubation with a pepsin-HCl mixture,then mixed for 2 h with bile salts and pancreatin.After digestion the samples were acidified and HPLC assayed.A significant(p<0.05)decrease in nutraceuticals content was noted during the intestinal phase with more reduction in gamma-aminobutyric acid(34.91–51.14%)compared to that of flavonols(16.58–28.90%),1-deoxynojirimycin(17.56–20.42%)and phenolic acids(0.53–0.67%)in the gastric digesta.Although encapsulation was observed to enhance the bioaccessibility,negative effects were found in terms of the bioefficiency and bioavailability.Furthermore,encapsulation techniques mostly affected the ion reducing capacity than the radical scavenging capacity.The outcomes suggested that carriers had a major effect on the digestibility and antioxidative activity,whilst the drying techniques mostly affect the bioaccessibility and bioavailability of the flavonols.
文摘A growing number of international studies have highlighted that ambient air pollution exposures are related to different health outcomes. To do so, researchers need to estimate exposure levels to air pollution throughout everyday life. In the literature, the most commonly used estimate is based on home address only or taking into account, in addition, the work address. However, several studies have shown the importance of daily mobility in the estimate of exposure to air pollutants. In this context, we developed an R procedure that estimates individual exposures combining home addresses, several important places, and itineraries of the principal mobility during a week. It supplies researchers a useful tool to calculate individual daily exposition to air pollutants weighting by the time spent at each of the most frequented locations (work, shopping, residential address, etc.) and while commuting. This task requires the efficient calculation of travel time matrices or the examination of multimodal transport routes. This procedure is freely available from the Equit’Area project website: (https://www.equitarea.org). This procedure is structured in three parts: the first part is to create a network, the second allows to estimate main itineraries of the daily mobility and the last one tries to reconstitute the level of air pollution exposure. One main advantage of the tool is that the procedure can be used with different spatial scales and for any air pollutant.
文摘In African communities, traditional beer drinking remains a unifying factor within its populations both socially, commercially, culturally, politically, in health and nutrition and for some ritual practices. In this research a field survey was carried out to investigate the consumption of corn beer and in particular <i>Nkang</i> in the North-West Region of Cameroon. The tools that were employed to carry out these investigations included face-to-face interviews and the use of properly designed questionnaires. Results from the survey showed that three types of maize-based beverages are drunk in the North-West Region of Cameroon, which are locally called <i>Kwacha</i> (whitish, most viscous and most turbid), <i>Sha-ah</i> (cream white, viscous and turbid) and <i>Nkang</i> (dark brown, least viscous and least turbid) in terms of colour, viscosity and turbidity. The percentage awareness of the existence of these beers from the sampled population gave the following values;60.9% for <i>Kwacha</i>, 100% for <i>Sha-ah</i> and 89.1% for <i>Nkang</i>. Nonetheless, 54.5% of the 60.9% of those who were aware of the existence of <i>kwacha</i> had at least tasted it. Also 98.2% out of the 100% for <i>Sha-ah</i> and 85.5% out of 89.1% for <i>Nkang</i> had tasted them, too. <i>Nkang</i> was found to be the most preferred to <i>Sha-ah</i> then <i>Kwacha</i> in that order by the consumers since <i>Nkang</i> is very tasteful, least alcoholic, least turbid, least viscous, has the most attractive colour than the others, has a significant impact on the culture of some localities in this region and as well as it is natural and nutritious. However, <i>Nkang</i> as well as the other two has varying organoleptic properties, unsatisfactory conservation and short shelf-life. Hence are consumed within a short period of time from their production. Because of the low alcoholic content of <i>Nkang</i>, the beverage is consumed by both adults (most elderly), children, those who have health problems and it is mostly preferred by some Christians th
文摘Bio-glycerol was synthesized from Cameroon palm kernel oil (PKO) through the transesterification procedure. Palm kernel oil extracted from palm kernel seeds using mechanical expression and solvent extraction was purified and characterized by physico-chemical methods and used in the transesterification process to give biodiesel and bio-glycerol. The biodiesel was purified and characterized as reported in previous articles. Our focus in this article is on glycerol, an important by-product of the transesterification process which has potential pharmaceutical, cosmetic and engineering applications. The bio-glycerol was purified by acidification and the purified glycerol was subjected to physical and chemical characterization. The specific gravity of glycerol was obtained as 1.2 kg/L, viscosity at 40°C gave 1500 cSt and 500 cSt at 100°C;pH was 7.4;the flash point was 160°C, and the ASTM color was 2.0 before purification and zero after purification. The sulfur content was 0.016%w/v. This sulfur content is low thus posing no environment threat. The chemical composition of the synthesized bio-glycerol determined using IR spectroscopy and gas chromatography-mass spectrometry (GC-MS) confirmed the known chemical structure of glycerol. The purification and analysis of bio-glycerol is important as it can find applications in the pharmaceutical, cosmetic and food industries inter alia.
文摘Particle size fractionation by sieving is used to optimize antioxydant potential of natural substances. The aim of the present study was to evaluate particle size effects on antioxidant and hepatoprotective potential of Eucalyptus camaldulensis essential oils (EO) on CCl<sub>4</sub>-induced hepatic damage in Wistar rats. Animals were daily orally treated with the EOs extracted by hydrodistillation from powder sieved at four particle sizes (≥355, 200 - 355, 100 - 200, ≤100 μm) and those of the unsieved powder at dose of 50 mg/Kg for 7 days. Compounds that are evaluated for these activities are hydrocarbons and oxygenated terpenes that were identified and quantified by GC/MS. Activities of enzymes markers of hepatocellular damage in serum and antioxidant enzymes in the liver homogenates were measured. In this research, EOs significantly prevented the increase in serum ALT and AST (p < 0.05), total cholesterol, triglyceride and LDL-cholesterol level in acute liver damage induced by CCl<sub>4</sub> and significant increase level of plasma HDL-cholesterol. Also, significantly (p < 0.05) decreased the extent of malondialdehyde (MDA) formation and elevated the activities of superoxide dismutase (SOD) and catalase (CAT) liver in comparison to negative control group. The best antioxidant and hepatoprotective activities were those of EOs from two fine powder fractions (≤100 μm and 100 - 200 μm) was correlated to their high concentration in oxygenated terpenes (70.9% and 46.4%, respectively), when compared to the large particles (200 - 355 μm and ≥355 μm, with 33.3% and 41.8%, respectively) and unsieved powder (37.4%).
基金TWAS-CSIR postgraduate fellowship program(FR number:3240280447 to Mr.Nobossé).
文摘Moringa oleifera leaves are an important source of dietary phytochemicals,such as flavonoids with high antioxidant activity(AOA).These components are however influenced by the post-harvest treatments applied as well as the processing conditions.Hence,it is crucial to determine the most appropriate post-harvest treatment that preserves or enhances AOA.To this effect the influence of steam blanching,fermentation/oxidation,oven drying and roasting of fresh Moringa leaves on their AOA was investigated.Processing conditions of time and temperature for each treatment were optimised using response surface methodology.The effect of the different treatments at optimal conditions on phenolic profile and AOA were compared.Roasting achieved the most significant(p<0.05)improvement in phenolics(43%)and AOA(22–31%),which was accompanied by the formation of 2 new compounds,quercetin-3-O-acetylglucoside and Quercetine-3-O-rhamnoside.Steam blanching had the most deleterious effect on phenolics(-31%)and AOA.Post-harvest treatments qualitatively and quantitatively affect phytochemical profile of Moringa leaves.
