61 research outputs found
Control of konzo in the Democratic Republic of Congo
Konzo is an upper motor neuron disease that causes irreversible paralysis of the legs mainly in children and young women^1,2^, due to consumption of large amounts of cyanogens from poorly processed cassava, the staple food of tropical Africa^3^. Konzo occurs in the Democratic Republic of Congo (DRC),Mozambique, Tanzania, Cameroon, Central African Republic and Angola. In March 2010 the wetting method, which removes cyanogens from cassava flour^4,5,6^, was taught to and used by the mothers of Kay Kalenge village. This reduced the total cyanide content of cassava flour to the FAO/WHO limit of 10ppm^7^. Cyanogen intake of school children, monitored by urinary thiocyanate analyses, decreased from mean values of 332 to 130 μmole/L. The percentage of urine samples that exceeded the danger level of about 350 μmole/L decreased from 26 in March 2010 to zero by May 2011. In 2009 there were many new cases of konzo, but none in 2010-2011. Konzo was first identified in1938 in Popokabaka area^8^ and it has now been prevented for the first time in the same area. This methodology is being used in three villages in Boko area and we believe it is the way to control konzo in tropical Africa
A European Concern? Genetic Structure and Expansion of Golden Jackals (Canis aureus) in Europe and the Caucasus
In the first continent-wide study of the golden jackal (Canis aureus), we characterised its population genetic structure and attempted to identify the origin of European populations. This provided a unique insight into genetic characteristics of a native carnivore population with rapid large-scale expansion. We analysed 15 microsatellite markers and a 406 basepair fragment of the mitochondrial control region. Bayesian-based and principal components methods were applied to evaluate whether the geographical grouping of samples corresponded with genetic groups. Our analysis revealed low levels of genetic diversity, reflecting the unique history of the golden jackal among Europe’s native carnivores. The results suggest ongoing gene flow between south-eastern Europe and the Caucasus, with both contributing to the Baltic population, which appeared only recently. The population from the Peloponnese Peninsula in southern Greece forms a common genetic cluster with samples from south-eastern Europe (ΔK approach in STRUCTURE, Principal Components Analysis [PCA]), although the results based on BAPS and the estimated likelihood in STRUCTURE indicate that Peloponnesian jackals may represent a distinct population. Moreover, analyses of population structure also suggest either genetic distinctiveness of the island population from Samos near the coast of Asia Minor (BAPS, most STRUCTURE, PCA), or possibly its connection with the Caucasus population (one analysis in STRUCTURE). We speculate from our results that ancient Mediterranean jackal populations have persisted to the present day, and have merged with jackals colonising from Asia. These data also suggest that new populations of the golden jackal may be founded by long-distance dispersal, and thus should not be treated as an invasive alien species, i.e. an organism that is “non-native to an ecosystem, and which may cause economic or environmental harm or adversely affect human health”. These insights into the genetic structure and ancestry of Baltic jackals have important implications for management and conservation of jackals in Europe. The golden jackal is listed as an Annex V species in the EU Habitats Directive and as such, considering also the results presented here, should be legally protected in all EU member states
Recent Advances in Adhesive Bonding of 3D-Printed Parts and Methods to Increase their Mechanical Performance
The use of additive manufacturing (AM) has revolutionized the production of polymer-based materials, offering a wide range of design possibilities and geometric complexity. However, due to the limitations of 3D printers to produce large parts, the parts often must be printed in several separate components and further joined together to obtain the final 3D-printed part. 3D printing can be used to produce only the most complex parts, which can be further combined with simple, non-printed parts from other materials to make the final product. One way to join 3D-printed part is an adhesive-bonded method. This paper focuses on the recent advances in adhesive bonding techniques for 3D-printed parts and explores various methods to enhance their mechanical performance. The benefits and limitations of each technique were discussed, and highlighted promising paths for future research. Finally, this paper provides a comprehensive overview of the current strategies to improve the mechanical performance of adhesive joints with AM-based adherents, offering guidance for the design and fabrication of high-performance structures in a range of applications. It was concluded that the configuration of the bonding area represents an essential parameter that directly influences the bonding strength and overall structural integrity of AM adhesive joints, and that the implementation of customized joint geometries can lead to a substantial enhancement in the joint strength of 3D-printed parts. The incorporation of reinforcing materials, optimization of the printing parameters of adherents, pre and post-treatment methods show potential in enhancing the bonding strength of the 3D-printed joints. The synergistic integration of these cutting-edge technologies can yield mutual advantages that complement each other, ultimately resulting in an enhanced overall performance for AM parts
Mechanical Characterization of Filler Modified ABS 3D Printed Composites Made via Fused Filament Fabrication
Rapid prototyping (also known as additive manufacturing, AM) is a quickly developing process with increasing new applications in a large variety of industrial sectors (i.e., aerospace, automotive, medical, among others.) However, despite the great advantage of a decoupled price to part complexity of an AM fabricated structure, the material properties (largely governed by filament material and printing parameters) still present a significant limiting factor. In this context, the development of new filament materials for a wider range of applications has great potential. In this study, the influence of micro-scale filler reinforcement (powders), both natural (curauá) and synthetic (glass fibre), in the fabrication of an Acrylonitrile Butadiene Styrene (ABS) filament was evaluated. The filler was controlled by weight fraction (~1%) and the filament was fabricated via extrusion. A commercially available 3D printer was used to print tensile and flexural specimens for mechanical characterization as per ASTM standards. The fracture morphology was analysed after tensile testing via optical microscopy in order to evaluate the effect of the fillers on the material deposition and void formation. No significant variation in the tensile properties was reported, except for the strain at failure, while more significant flexural strength variation was observed as a function of filler material. The fillers presented a significant effect on the void density of the fractured surface. It was demonstrated that this simple fabrication technique can generate novel filament materials that may enhance the mechanical properties or widen the range of application (e.g., faster decomposition times in nature for single-use plastics due to the hydrophilic nature of the natural filler and lower water absorption of the hydrophobic synthetic filler for marine environment applications)
Tensile Behaviour of a Structural Adhesive at High Temperatures by the eXtended Finite Element Method
Making cassava flour safe using the wetting method
Many people, particularly in Africa, suffer various conditions from eating bitter cassava which contains poisonous cyanogens. As well as poisoning, which sometimes causes death, these conditions include konzo, an irreversible paralysis of the legs, which affects mainly children and young women, impaired neurocognition in children, tropical ataxic neuropathy in older people, and aggravation of iodine deficiency disorders (such as goitre and cretinism) in iodine deficient areas. The wetting method removes residual cyanogens, and is an additional method of processing cassava flour after its preparation by one of the traditional methods. The wetting method is simple and easy to use, the traditional thick porridge (fufu or ugali) made from the treated flour tastes very good, and the method is readily accepted by rural women in East and Central Africa. Regular use of the wetting method by rural women in 13 villages in the Democratic Republic of Congo has prevented konzo amongst more than 9,000 people. We recommend that the wetting method be used as an additional method to traditional methods to remove cyanogens from cassava flour in tropical Africa
Making cassava flour safe using the wetting method
Many people, particularly in Africa, suffer various conditions from eating bitter cassava which contains poisonous cyanogens. As well as poisoning, which sometimes causes death, these conditions include konzo, an irreversible paralysis of the legs, which affects mainly children and young women, impaired neurocognition in children, tropical ataxic neuropathy in older people, and aggravation of iodine deficiency disorders (such as goitre and cretinism) in iodine deficient areas. The wetting method removes residual cyanogens, and is an additional method of processing cassava flour after its preparation by one of the traditional methods. The wetting method is simple and easy to use, the traditional thick porridge (fufu or ugali) made from the treated flour tastes very good, and the method is readily accepted by rural women in East and Central Africa. Regular use of the wetting method by rural women in 13 villages in the Democratic Republic of Congo has prevented konzo amongst more than 9,000 people. We recommend that the wetting method be used as an additional method to traditional methods to remove cyanogens from cassava flour in tropical Africa
Konzo and dietary pattern in cassava-consuming populations of Popokabaka, Democratic Republic of Congo
Food frequencies and 24h diet recall were registered from 487 randomly selected heads of household in Popokabaka (Bandundu Province, DRC) where the first cases of konzo were reported more than seventy years ago. Konzo is still occurring in this area with a prevalence of 1.4%.. High prevalence of konzo was found to be associated with female gender (P = 0.0024), unmarried status (P = 0.030), illiteracy (P = 0.021), farmer as main occupation (P< 0.05) and with consumption of cassava from own farm land (P = 0.045). The diet was largely dominated by cassava. Luku, cassava flour stiff porridge, was consumed at least once during the day in 99.2% of households. A median of 304 g (max 592 g; min 120 g) of cassava flour providing 1070 Kcal (max 2085 Kcal; Min 422 Kcal)/ day/person was used to prepare luku. Saka-saka (pounded cassava leaves) (40%), cowpeas (30%), sesame (23.2%), mbondi (Salacia pynaertii) (18.1%), mushrooms (17.7%) and mfumbwa (Gnetum Africanum) (11.3%) were consumed as side-dishes with luku. These results showed that major foods consumed are of poor quality in protein, especially in sulphur containing amino acids
Control of konzo in DRC using the wetting method on cassava flour
Fifty konzo cases were identified in four villages in Popokabaka Health Zone, DRC. One third of people had only one meal per day, mainly of cassava flour consumed as a thick porridge (fufu) and pounded, boiled cassava leaves. Retention of cyanogens in flour resulted from short soaking of cassava roots. A 1.5. years intervention was made in the largest village Kay Kalenge, where the wetting method was taught to all women of the village, who accepted it willingly. The total cyanide content of cassava flour was reduced to below 10. ppm. Fufu from treated flour tasted and stored better than fufu from untreated flour. The mean urinary thiocyanate content of 100 school children reduced from 332 to 130. μmole/L and the number of samples exceeding 350. μmole/L decreased from 26 to 0 during the intervention. No new konzo cases occurred, which included two dry seasons when konzo peaks. Konzo was first identified by Dr. Trolli in 1938 in Popokabaka Health Zone and it has now been prevented for the first time in the same area. The methodology is now in use in Boko Health Zone and we believe it is the most effective way to control konzo in tropical Africa
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