ABSTRACT
Precipitation hardening ferritic pearlitic (PHFP) grade 34CrMo4 steel is subjected to thermomechanical processing (TMP) for e = 0.2, e = 0.4 and e = 0.6 followed by furnace-, natural air- and forced air- cooling. Optical microscopy revealed the ASTM grain size number to change from 6 for the starting sample to 5-6 for the furnace cooled, 7-8 for natural air cooled and 8-9 for forced air cooled samples. A transformation from initial ferrito-pearlitic banded microstructure to almost equiaxed coarse grained ferrito-pearlitic microstructure on furnace cooling, finely distributed ferrito-bainitic microstructure on natural and forced air cooling respectively was noted. For natural and forced air cooling, the samples showed fine grained microstructure comprising of ferrite along with bainite, which became finer with increasing strain as well as cooling rate. The occurrence of ferrito-bainitic microstructures got clearly resolved in scanning electron microscopy (SEM). The microstructure of as received annealed sample in SEM revealed proeutectoid ferrite, almost linear uniformly spaced ferrite and cementite lamellae inside pearlitic nodule and uniformly distributed carbides throughout the matrix. The carbide size, otherwise remaining unchanged around 40 nm, got reduced to 23 nm only in case of forced air cooling. Extreme TMP conditions produced ferrite and broken fine colonies of bainite. The pearlite and bainite morphology assumed various forms of interlamellar spacing based on TMP. The forced air cooled (e = 0.6) samples demonstrated the maximum improvement in yield strength (YS = 700 MPa) by almost more than 2.5 times and in ultimate tensile strength (UTS = 790 MPa) by almost 40%. A maximum improvement in toughness (= 54 Joule) by almost 10% without loss of any other properties was observed for the TMP comprising of e = 0.4 and furnace cooling.
ABSTRACT
Using a matched case-control design, we sought to determine whether the odds of konzo, a distinct spastic paraparesis associated with food (cassava) cyanogenic exposure in the tropics, were associated with lower cyanide detoxification rates (CDR) and malnutrition. Children with konzo (N=122, 5-17 years of age) were age- and sex-matched with presumably healthy controls (N=87) and assessed for motor and cognition performances, cyanogenic exposure, nutritional status, and cyanide detoxification rates (CDR). Cyanogenic exposure was ascertained by thiocyanate (SCN) concentrations in plasma (P-SCN) and urine (U-SCN). Children with a height-for-age z-score (HAZNCHS)<-2 were classified as nutritionally stunted. CDR was measured as time required to convert cyanide to SCN, and expressed as ms/µmol SCN/mg protein or as mmolSCN/ml plasma/min. Mean (SD) U-SCN in children with konzo was 521.9 (353.6) µmol/l and was, significantly higher than 384.6 (223.7) µmol/l in those without konzo. Conditional regression analysis of data for age- and sex- matched case-control pairs showed that konzo was associated with stunting (OR: 5.8; 95% CI: 2.7-12.8; p<0.01; N=83 paired groups) and higher U-SCN (OR: 1.1; 95% CI: 1.02-1.20 per 50-µmol increase in U-SCN; p=0.02; N=47 paired groups). After adjusting for stunting and U-SCN, the odds of developing konzo was reduced by 63% (95% CI: 11-85%, p=0.03; N=41 paired groups) for each 5mmol SCN/(ml plasma/min)-increase in CDR. Linear regression analysis indicated a significant association between BOT-2 or KABC-II scores and both the HAZNCHS z-score and the U-SCN concentration, but not the CDR. Our findings provide evidence in support of interventions to remove cyanogenic compounds from cassava prior to human consumption or, peharps, enhance the detoxification of cyanide in those relying on the cassava as the main source of food.
Subject(s)
Cyanides/toxicity , Paraparesis, Tropical Spastic/chemically induced , Sulfurtransferases/metabolism , Adolescent , Analysis of Variance , Case-Control Studies , Child , Child, Preschool , Cognition Disorders/etiology , Female , Humans , Male , Motor Disorders/etiology , Nitriles , Paraparesis, Tropical Spastic/metabolism , Retrospective Studies , Statistics, NonparametricABSTRACT
Introduction: Déterminer la prévalence, la connaissance et le degré de contrôle de l'hypertension et analyser et comparer ces indicateurs en fonction des facteurs socio démographiques, héréditaires et environnement aux dans la population adulte de la ville de Kisangani, chef-lieu de la province Orientale en RD Congo. Méthodes: Nous avons mené une enquête transversale dans la population de Kisangani de juin 2010 à février 2011. L'étude a porté sur 1934 sujets âgés de â¥18 ans à l'exclusion des femmes enceintes. Les sujets ont été sélectionnés par échantillonnage aléatoire en grappes à quatre niveaux. Résultats: La prévalence de l'hypertension à Kisangani était de 28,3%. Parmi les sujets hypertendus, 72,2% se connaissaient hypertendus, 42,4% avaient leur hypertension contrôlée, 18,4% avaient l'hypertension au stade 2 et 6,5% avaient l'hypertension au stade 3. La prévalence de l'obésité était de 8%, celle de l'obésité abdominale de 13,5%. Les facteurs significativement associés à l'hypertension étaient l'âge, le sexe, le milieu de résidence, le niveau de scolarité, le niveau de revenu financier,la charge sociale,le statut dans le ménage,la prise des boissons alcoolisées, la sédentarité, l'hérédité d'hypertension, l'hérédité d'obésité, l'obésité et l'obésité abdominale. Conclusion: L'hypertension est très fréquente parmi les populations de Kisangani, aussi bien en milieu urbain qu'en milieu urbano-rural. Le niveau de contrôle de l'hypertension est plutôt satisfaisant; cependant la proportion d'hypertendus qui s'ignorent est préoccupante. Les systèmes des soins de santé de la ville de Kisangani devront s'atteler à améliorer les stratégies de dépistage de nouvelle «épidémie»
Subject(s)
Democratic Republic of the Congo , Health Knowledge, Attitudes, Practice , Hypertension/diagnosis , Hypertension/prevention & control , PrevalenceABSTRACT
Introduction : La meningite est un probleme de sante publique dans les pays tropicaux. Elle atteint surtout les enfants et les jeunes adultes et sevit sous forme d'epidemies explosives tous les 10 a 12 ans. En Republique Democratique du Congo (RDC); on a recense au premier trimestre de 2010; 1852 cas dont 182 deces. Une epidemie a fait 17 morts a Kisangani en 2009.Cette etude avait pour objectifs d'identifier le germe en cause dans l'epidemie de 2009; de comparer les resultats biologiques de la meningite selon la coloration au gram; la culture et le test au latex de Pastorexrealises au niveau du liquide cephalorachidien (LCR).Materiel et Methode : Notre echantillon est fait de 33 echantillons de LCR sur lesquels la coloration de Gram; la culture et le test serologique au latex de Pastorex ont ete effectues. Ces echantillons ont ete preleves chez des malades atteints de meningite.Resultat : La coloration au gram a ete positive pour 94 des echantillons contre 6 des echantillons negatifs; 82 des echantillons ont montre des diplocoques gram negatifs. Le test de Pastorex a pour sa part identifie Neisseria meningitidis type C(NMC) dans 87;9 comme agent causal de cette epidemie de meningite. La culture sur gelose au sang du LCR etait concluante chez seulement 51;5 des echantillons. Conclusion : Dans la meningite a N. meningitidis; le test de Pastorexaun avantage diagnostic plus que la culture sur gelose au sang et permet egalement d'identifier le type de N.meningitidis
Subject(s)
Democratic Republic of the Congo , Meningitis, Meningococcal , Meningitis, Meningococcal/diagnosis , Meningitis, Meningococcal/virology , Serologic TestsABSTRACT
Objectives: The role of blood transfusion in the spread of hepatitis C virus (HCV) is of concern in the DRC. Screened since the end of 2004 in blood donors, few data are however available on HCV in Kisangani. A study is needed to determine the seroprevalence of HCV in blood donors. Patients and method: 1247 blood samples collected from all volunteer blood donors who donated blood from August 1, 2005 to April 30, 2006 at the Provincial Blood Transfusion Centre were tested for anti-HCV antibodies. At the same time as HCV serology, markers for HIV and HBV were tested. Results: A total of 51(4.1%) volunteer blood donors (Table I) were HCV antibody positive. Fifty-two (4.2%) of the subjects were HIV positive and 60 (4.8%) were HBV positive. The mean age of HCV-positive donors was 31.4 years (±13.1) (Table II). HCV-positive seropositivity is lower among donors aged 17 to 24 years compared with those aged 25 years and older (p < 0.05). Positive HCV seropositivity is not related to gender. Conclusion: The seroprevalence of hepatitis C virus is relatively high like that of HIV among volunteer blood donors in Kisangani. It justifies that every blood donor be tested for HCV in order to prevent its transmission in Kisangani
