A thermo-mechanically loaded rotating FGM cylindrical pressure vessels under parabolic changing properties: An analytical and numerical analysis.

This study aims to develop an exact analytical solution for steady-state thermo-mechanical stress in a functionally graded (FG) thick-walled cylindrical vessel. The cylinder is subjected to combined rotational speed and internal pressures while the thermal load is with convective and radiative boundary conditions. The dimensionless governing equations and boundary conditions, represented as a quartic equation, are derived and solved using Ferrari's method. The temperature, displacement, and stress fields across the thick-walled cylindrical vessel are calculated by finding the roots of the quartic equation. In order to investigate the accuracy of the exact analytical solution, a numerical model is constructed based on a standard Galerkin discretization approach of the finite element method (FEM). The analytical solutions and the results obtained through FEM show a high level of agreement. Furthermore, the study analyzes the effects of material parameters on temperature, displacement, and stress fields. Displacement, temperature, and stress fields are presented in the form of dimensionless graphs along the radial direction. For the considered parametric studies, results revealed that parabolic grading is beneficial than conventional grading. This study reveals that for the thermal loading, the maximum temperature, displacement, and tangential stress decrease for the parabolic grading. A similar but lower value of temperature, displacement, and tangential stress is also observed in the case of thermomechanical loading. This study is expected to assist in the assessment of the reliability of load calculations and contribute to the overall durability of pressure vessels. The results obtained from this study can provide valuable insights into thermo-elasticity and the thermo-mechanical behavior of thick-walled cylindrical vessels and can aid in the design and optimization of such systems.

Finite element analysis of a generalized rotating FGM vessel subjected to thermo-mechanical loadings: Effect of Poisson ratio and inhomogeneity parameters.

Cylinders and thick walled cylindrical shells are commonly utilized in several industries to transport and store fluids under certain pressure and temperature conditions. In the present paper, a numerical solution is developed in order to investigate displacement, temperature and stress fields in a rotating pressure vessel made of generalized functionally graded material (FGM) subjected to different thermo-mechanical boundary conditions. The aim is to investigate the effect of Poisson ratio, internal pressure and temperature and inhomogeneity parameters on the stress and deformation distributions of the rotating pressure vessel. The material is considered isotropic nonhomogeneous and linearly elastic with its properties varying along the radial direction. Additionally, certain conditions, such as exterior or interior problems where r → ∞ or r → 0, respectively, are impossible to resolve using the variation of attributes as a power-law distribution. An approach to the spatial Young modulus distribution that is more broad has been suggested in the literature which can be applied to such physical challenges. The rotation of the pressure vessel is considered in the analysis, and the temperature distribution is assumed to be non-uniform. Since an analytical solution to the differential equation is not accessible, the conventional Galerkin discretization approach of the Finite Element Method (FEM) is applied, nowadays is considered one of the main numerical tools for solving Boundary Value Problems (BVP). It is addressed how stress, strain, and displacement are affected by the inhomogeneity parameter, rotation speed, pressure, temperature, and Poisson ratio. The examination of the various findings indicates that changes in the temperature profile, rotation, and inhomogeneity parameter on the thermoelastic field have a substantial impact on the stress and strain in the FGM cylinder. The findings indicate that the Poisson ratio and inhomogeneity parameters have a significant impact on the stress and deformation distributions. According to the results, the above-mentioned parameters can be adapted to control the thermoelastic filed in a FGM cylinder. The present research offers significant perspectives on the development and enhancement of rotating FGM pressure vessels intended for high-temperature applications.

[Diabetes and erectile dysfunction in Morocco: epidemiological study among outpatients]. / Diabète et dysfonction erectile au Maroc : etude epidémiologique auprès d'une population de consultants.

We studied the relationship between erectile dysfunction (ED) and diabetes among 189 men (> 40 years) attending primary health care centres in Morocco. Of the 89 diabetic men, 82% had ED while only 17% of the 100 non-diabetic men had ED. The frequency of ED among diabetic men increased with age, from 60% in those aged 40-49 years to 94.95% in those aged > or = 60 years (from 6.3% to 35.4% in men without diabetes for similar ages). ED was reported by 93.3% of diabetic men who had had diabetes for > 15 years. The frequency of ED did not differ with type of diabetes but it was significantly commoner in diabetic men with a low level of education and with hypertension.

[Part of Chlamydia pneumoniae in atherosclerosis and exacerbation of chronic obstructive pulmonary disease and asthma]. / La part de Chlamydia pneumoniae dans l'athérosclérose et les exacerbations de bronchopneumopathie chronique obstructive et d'asthme.

Chlamydia pneumoniae infection has been often associated with several chronic diseases including asthma and chronic obstructive pulmonary diseases (COPD). The spectrum of Chlamydia pneumoniae infection has been expanded to the association with coronary heart disease (CHD). In Morocco, the implication of Chlamydia pneumoniae infection in these pathologies is unknown. The aim of our study was to determine the relationship between infection with Chlamydia pneumoniae and respiratory pathology and atherosclerosis. The patients were from two departments (department of respiratory disease and of cardiology), and presented exacerbation of COPD and asthma or atherosclerosis. The mean age was 45 years a with a 1.7 sex ratio for the first population and 61 years with a 1.4 sex ratio for the second population. Serological diagnosis of Chlamydia pneumoniae infection has been determined by microimmunofluorescence (MIF). All samples were tested for anti-Chlamydia pneumoniae IgG, IgA and IgM. In the first group, we found 42 % positive for IgG, 11 % for IgA, and no case for IgM. In the second group the presence of anti-Chlamydia pneumoniae IgG was observed in 67.5 % cases, IgA in 16.5 % cases and IgM in 2 % cases, 14 % of patients had negative serology for IgA, IgG, and IgM. Our results are in accord to those reported by other studies. According to these results, it seems that a certain degree of association exists between Chlamydia pneumoniae infection and exacerbation of COPD, asthma and atherosclerosis which should be of importance on a therapeutic point of view.

The gene distribution in the genomes of pea, tomato and date palm.

The vast majority of genes of maize, rice, barley and wheat are contained in long gene-rich regions (collectively called the 'gene space') separated by long gene-empty regions. The gene space covers a narrow, 0.8-1.6%, GC range, possibly because of the presence of abundant transposons. Here we report that the gene space is not an exclusive property of Gramineae, because it also exists in the large genome of pea (5000 Mb). Moreover, the gene space is not just dependent upon genome size, since a gene space is found in rice (415 Mb), but not in Arabidopsis (120 Mb), nor in two other plants investigated in the present work, date palm (250 Mb) and tomato (1000 Mb).

Characterization of a new leiurotoxin I-like scorpion toxin. PO5 from Androctonus mauretanicus mauretanicus.

Three novel peptide inhibitors of the SKCa channels were purified to homogeneity from the venom of the scorpion Androctonus mauretanicus mauretanicus using one step of RP-HPLC and competition assays with [125I]apamin to rat brain synaptosomes. PO1, PO2 and PO5 have K0.5 of 100, 100 and 0.02 nM, respectively, for the apamin binding site. The sequence of PO5 was established and compared to that of other scorpion toxins active on K+ channels: it contains 31 residues and has a free carboxyl end. it shares sequence similarity with apamin and leiurotoxin I.

Direct genotyping and nucleotide sequence analysis of VS1 and VS2 of the Omp1 gene of Chlamydia trachomatis from Moroccan trachomatous specimens.

To determine the range of ocular strains of Chlamydia trachomatis circulating in southern Morocco, where trachoma is endemic, and to compare the value of the molecular methods for genotyping C. trachomatis, ocular specimens were subjected to a direct Omp1 PCR-restriction fragment length polymorphism (RFLP)-based analysis and direct sequencing. PCR-RFLP analysis shows that the Ba genotype represents the most frequent one (63%), followed by genotype A (45%), whereas no B or C genotypes were identified among the 53 out of 108 specimens that were strongly positive in the Omp1 CT1-CT5 PCR. Our results further show that the notion of interfamily and intrafamily transmission is very likely. To confirm the genotype identity of C. trachomatis as determined by PCR-RFLP, 16 selected specimens were sequenced across variable sequence 1 (VS1) and 2 (VS2). No discrepancies were found between PCR-RFLP typing and the genotype identity confirmed by nucleotide sequencing of the PCR product. Our results clearly indicate that both molecular methods of typing chlamydiae (i.e., PCR-RFLP and sequencing) are important and have specific applications for clinical epidemiological purposes. This is the case for individuals infected with more than one clonal population of C. trachomatis. The unambiguous nucleotide sequencing therefore defines an important epidemiologic descriptor for the infected patient whether the source is from a clonal population of organisms or whether it represents a more dynamic process of strain dominance or genetic change. Furthermore, Omp1 genotyping affords the necessary approach to epidemiologic investigations in areas of the world endemic for trachoma, where only one or two serovars are known to predominate.

Different cytokine profiles of peripheral blood mononuclear cells from patients with persistent and self-limited hepatitis C virus infection.

An imbalance between T helper cell Th1 and Th2 like cytokines has been described in several chronic infectious diseases. In an attempt to characterise the mechanism responsible for viral persistence in hepatitis C virus (HCV)-related chronic infection, we analyzed Th1 cytokines (IL-2, IL-12, IFN-gamma) and Th2 cytokines (IL-4, IL-10) production by phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC) derived from ten patients with viremic chronic hepatitis C, five healthy HCV seropositive individuals and four HCV seronegative individuals. Cytokine production was determined by enzyme-linked immunosorbent assay (ELISA) after 72 h of stimulation. The results showed that the production of IFN-gamma by PHA-stimulated PBMC was decreased in patients with hepatitis C infection (P=0.05). IL-4 production was not detected in both patients and controls, while no difference was observed for IL-2, IL-10 and IL-12 production between patients and controls. Furthermore, IL-12 and IFN-gamma production was weaker in patients with viremic chronic hepatitis C than in subjects who were able to clear the virus (P=0.01; P=0.03, respectively). These results clearly indicate that a defect both in IL-12 and IFN-gamma production may contribute to the persistence of HCV infection.

Analysis of apoptosis and a Th1/Th2 phenotype in HIV-infected patients.

Lymphocytes from HIV patients, unlike those from normal HIV-negative subjects, underwent apoptosis upon in vitro culture. We found that the percentage of lymphocytes undergoing apoptosis was significantly higher (P = 0.005) in patients with low CD4 cell counts (< 200 CD4 cells/microliter) (60%) than in patients at earlier stage (> 500 CD4 cells/microliter) (35%). Serum IgE levels increased in two of six patients at last stage and in two of five patients at earlier stage. Spontaneous production of both IL-2 and IL-10, by peripheral blood mononuclear cells (PBMC) after 48 h in culture, was greater in HIV-infected subjects and increased with disease progression. IFN-gamma production was greater in HIV-infected subjects but there was no evident change with disease progression. IL-4 production was barely detectable or not detected in both HIV-infected and HIV-negative individuals. These results indicate that spontaneous apoptosis is associated with advanced disease. However, there was no evidence of in vivo switch from the Th1 to Th2 phenotype in HIV-infected patients.

A randomized study comparing two guidewire strategies for angioplasty of chronic total coronary occlusion.

Chronic total coronary occlusions were more frequently crossed using the Crosswire as a primary guidewire strategy than with the conventional strategy. This strategy resulted in a lower number of guidewires being used, a trend toward shorter procedural and fluoroscopy times, and decreased use of contrast media.

Establishment of T-lymphoid cell lines from Morroccan patients with tropical spastic paraparesis.

Two T-cell lines were established from peripheral blood mononuclear cells of two Moroccan patients with tropical spastic paraparesis and then named PR52 and PR144. The two cell lines showed a T lineage of activated CD4+ with high density of Tac+ (IL2 receptor). No expression of CD8 was observed. The virus particles were detected by reverse transcriptase activity and the viral antigens were also detected by immunofluorescence (IF) and Western blot. After six months of culture greater than 90% of the cells exhibited HTLVI antigen by IF. Lysate virus particles on Western blot analysis revealed p19,p24, and p53 gag protein similar to those detected in C91/PL virus particles from an adult T-cell leukemia (ATL) patient. gp46 and gp61 were also weakly detected. These two T-cell lines established will serve as substrate for further comparative studies on TSP and ATL isolates.

Scorpion envenomation and serotherapy in Morocco.

A clinical and biologic study was conducted in Morocco to assess the efficiency of antivenom therapy for treating victims of scorpion stings. Epidemiologic and clinical data were collected from 275 patients envenomed by Androctonus mauretanicus mauretanicus and Buthus occitanus scorpions. Patients received antivenom or other drugs. Blood samples were collected at the time of hospital admission and 1 hr and 3 hr after treatment. Serum venom levels were quantified by using an ELISA. An association was found between clinical signs of envenoming and the level of venom in serum. Patients classified as grade II (moderate envenoming) had higher serum levels of venom level than patients classified as grade I (mild envenoming). At admission to the hospital, the mean venom concentration was not significantly different between the group not treated with antivenom, the group who received 2-5 ml of antivenom, and the group who received 10 ml of antivenom. A significant decrease in serum venom levels and an improvement in the clinical conditions were observed in patients administered 10 ml of antivenom. The lower decrease in serum venom levels in patients who received 2-5 ml of antivenom was due to lower doses of antivenom. No difference in the venom concentration was observed in patients who were not treated with antivenom. The absence of administration of antivenom increased the risk of developing clinical signs at the end of the hospitalization period. However, this risk was much higher when more than 1 hr elapsed between the time of the scorpion sting and the time of hospital admission. The results demonstrate that antivenom is effective in decreasing circulating venom and morbidity. Serotherapy is more efficient when given as soon as possible after envenomation and with adequate quantities of antivenom.

Antiinflammatory mechanism of cordiachromene A action.

The mechanism of antiinflammatory action of cordiachromene A, isolated from the chloromethylenic extract of the ascidian Aplidium antillense or chemically synthesized, was studied using different in vivo and in vitro inhibition tests on enzymes of the cyclooxygenase cascade. Cordiachromene A inhibits prostacyclin synthesis and arachidonic acid metabolism but not phospholipase A2 and peroxidase. The mechanism of action, already known to be stereospecific, operates by cyclooxygenase inhibition.

Marine bioactive compounds: stereospecific anti-inflammatory activity of natural and synthetic cordiachromene A.

A new synthesis is proposed for cordiachromene A (CCA), a bioactive component of the ascidian Aplidium antillense Gravier, using a method producing a racemic mixture. The anti-inflammatory activities of a natural extract and a chemically synthetic form of CCA were assessed in vivo by carrageenan-induced rat-paw edema. The activity of synthetic CCA was confirmed by a test on kaolin-induced granuloma in the rat. Strong activities were measured for both CCA, but comparison of results of the first test suggests that only the natural optically active isomer has an anti-inflammatory effect. CCA is similar to indomethacin in its effect on carrageenan-induced rat-paw edema and ten times as active as phenylbutazone.

Cytogenetic survey of 53 Moroccan patients with acute myeloblastic leukemia.

We present a cytogenetic survey of chromosome aberrations for 53 Moroccan patients with acute myeloblastic leukemia (AML). Our 53 patients were 2 to 70 years old with 31 men and 22 women. The cytogenetic study was performed with the following three methods: first, relative proportion of normal (N) or abnormal (A) metaphases; second, presence of specific or random abnormalities; and third, karyotype complexity. Among 36 patients (67%) with a chromosomal abnormality, 18 (34%) showed a specific aberration. We have found t(9;22) in three patients (5%), chromosome 5 or 7 abnormality in six (11%), del(11)(q23) in three (6%), +21 in four (8%), and +8 in two (4%). Specific translocations associated with FAB type were found: t(8;21) with AML2 in 12 patients (23%) and t(9;11) with AML5 in one (2%). Rare abnormalities were also found: one patient with t(7;21) associated with AML2 and another patient with r(1) ring associated with AML1. We concluded that our study in a Moroccan population confirmed the relation between some specific abnormalities and the FAB classification. We have found a higher incidence for t(8;21) than usually described. Finally, we have identified chromosomal abnormalities t(7;21)(q22;p11) and r(1), rarely described before.

Chronic cases of tuberculosis in Casablanca, Morocco.

OBJECTIVE: To evaluate the prevalence and patterns of drug resistance of Mycobacterium tuberculosis isolates collected from patients with chronic tuberculosis in Casablanca, Morocco. METHODS: Between February 1996 and September 2001, 122 isolates were recovered from 112 different patients. The male to female ratio was 2.4. RESULTS: From February 1996 to May 1997, 77.5% of isolates were multidrug-resistant (MDR-TB), compared to 69.4% from February 1999 to May 2000 and 78.7% from June 2000 to September 2001. The prevalence of MDR-TB is similar from the initial to the last period of this study. Analysis of the 69 bp hypervariable region of the rpoB gene by DNA sequencing on 42 M. tuberculosis isolates (37 resistant, 5 sensitive) showed nine different types of mutations on codons rpoB 513, rpoB 516, rpoB 522, rpoB 523 and rpoB 526. A new point mutation was observed on codon rpoB 523 on one isolate. No mutation was detected on this rpoB region for four resistant isolates. CONCLUSION: The high rate of MDR-TB illustrates a serious problem. The public health authorities have introduced a new regimen protocol consisting of 3 months of kanamycin, ofloxacin, pyrazinamide and ethionamide, followed by 18 months of ofloxacin, pyrazinamide and ethionamide (3KOZEA/18OZEA) for this category of patients, and it is hoped that the additional use of ofloxacin during the intensive phase of treatment will reduce the rate of resistance.

Survey of primary drug resistance of Mycobacterium tuberculosis in Casablanca, Morocco.

SETTING: In 1990, a 6-month short-course regimen (2 SHRZ/4 RH) was introduced for the treatment of tuberculosis in Morocco. OBJECTIVE: To assess the efficacy of the national tuberculosis control programme, a prospective study of primary drug resistance was conducted from April 1992 to July 1994 in Casablanca. DESIGN: A total of 402 strains isolated from 402 patients living in Casablanca with no previous history of tuberculosis was included in the study. RESULTS: The overall rate of primary drug resistance to at least one drug was 23.9%; it was 19.7% to streptomycin, 11.4% to isoniazid, and 8.2% to both streptomycin and isoniazid. The rates of resistance to rifampicin and ethambutol were both less than 1%. The survey was divided into two periods of 14 months each. The rates of primary drug resistance increased from 21.1% to 27.6% during these two periods (Odds Ratio [OR] 1.43; 95% Confidence Interval [CI] 0.88 to 2.32); this increase occurred only for streptomycin (15.9% to 24.7%, OR 1.73; 95% CI 1.02 to 2.93). CONCLUSION: The rate of primary drug resistance of Mycobacterium tuberculosis in Casablanca has risen in recent years to an ominous level. Urgent measures are needed in order to interrupt this trend.

Variants of the human NRAMP1 gene and susceptibility to tuberculosis in Morocco.

It has been well established that the host genetic background is an important modulator of tuberculosis susceptibility. The NRAMP1 (alias SLC11A1) gene has been associated with tuberculosis susceptibility in several ethnic groups. Here we studied the association and linkage of NRAMP1 with tuberculosis in 116 nuclear families, comprising 211 affected offspring, from Casablanca, Morocco. All enrolled tuberculosis cases were culture-positive. No evidence was found of linkage or association of NRAMP1 with tuberculosis. These findings suggest heterogeneity in the genetic control of tuberculosis susceptibility.

Beneficial effect on serum apo AI, apo B and Lp AI levels of Ramadan fasting.

In order to investigate for the first time in Morocco the effect of fasting in Ramadan, the ninth lunar month of the muslim year, on lipoprotein metabolism, we determined the levels of serum apolipoproteins; apolipoprotein AI (apo AI), apo B, apo AIV and those of lipoprotein particles; apo AI-containing lipoprotein particles (Lp AI) and also apo AI and apo AII containing lipoprotein particles (Lp AI:AII) in a group of 32 healthy, volunteer adult males. Determination of all these parameters was carried out on each week of the month of Ramadan and the results are compared with the pre-fasting and the post-fasting values. Ramadan fasting reduces significantly serum apo B (P < 0.05), while serum apo AI is significantly increased (P < 0.05) compared with the pre-fasting period. The increase of apo AI occurred on day 29 of Ramadan by 11.8%. Serum apo AIV was unchanged during the fasting period indicating that food intake during Ramadan is not based on lipid diet. The observed diet pattern during Ramadan showed an increase of total energy intake based on carbohydrates (+1.4% of total energy), proteins (+0.4% of total energy) but not on fat (-0.7% of total energy), compared with a usual diet used in the rest of the year. The fat diet is high in monounsaturated (P < 0.05) and polyunsaturated fatty acid in contrast to saturated fatty acid which decreased (P < 0.05) during Ramadan. On the other hand, analysis of serum Lp AI and Lp AI:AII showed that the levels of Lp AI:AII were unchanged but those of Lp AI were significantly increased (P < 0.01) at the end of Ramadan. These findings show that feeding behaviour that occurs during Ramadan beneficially affects serum apolipoprotein metabolism and may contribute to prevention of cardiovascular diseases.

Analysis by high-performance liquid chromatography of Androctonus mauretanicus mauretanicus (black scorpion) venom.

The venom of the black scorpion, Androctonus mauretanicus mauretanicus, was obtained by means of manual stimulation and was analyzed using high-performance liquid chromatography. Starting from 20 mg of venom and using only two chromatographic steps, six toxins were purified to homogeneity. They have been characterized by their amino acid content and compared to those already isolated from a pool of venoms obtained using electric stimulation (Rosso and Rochat, Toxicon 23, 113-125, 1985). The toxins Amm I and Amm II were not found, suggesting either different levels of toxin expression or the existence of Androctonus mauretanicus mauretanicus subspecies. Using rat brain synaptosomes, it was demonstrated that the toxins Amm III, Amm IV and Amm V were alpha-toxins. The toxin Amm VI was neither alpha- or beta-toxin. Unexpectedly, the toxin Amm VII was found to be a beta-toxin, the first one identified in a north African scorpion venom. In addition, some toxins active on mammals exhibited different levels of specificity towards phylogenetically related groups of arthropods.