273 research outputs found

    The effect of silicone on some properties of flakeboard

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    Waxes are used as water repellent in wood composites, and there are only limited alternative waterrepellent systems for wood composites. The aim of this study was to investigate the effectiveness of a silicone compound as a water repellent for flakeboard and to compare the properties of boards made with silicone treated flakes to those made with commercial wax treated flakes. Three levels of silicone and wax application rates were used (0.25, 0.5, and I %). The hydrophobic nature of silicone-treated flakes was evaluated by measuring the contact angle and the rate of water absorption (W A) on the surface of the wood flake. The internal bonding strength (IB), the modulus of elasticity (MOE) and modulus of rupture (MOR) in bending regime, the W A, and the thickness swelling at edges of boards were evaluated. Results obtained showed that IB, MOE and MOR decreased as the concentration of silicone on the flakes increased from 0.25% to 1%. The IB, MOE and MOR of panels made with 0.25% siliconetreated flakes were comparable to boards made with 1% wax-treated flakes. Thickness swell at edges and WA were significantly reduced as the amount of silicone increased. No significant difference was found for the thickness swelling at edges and the W A between panels made with I % silicone-treated flakes and 1% waxtreated flakes. The silicone treated flakes had high water repellency

    Risk factors for surgical site infections after caesarean section at Yaounde, Cameroon

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    Background: Surgical site infection is the invasion by microorganisms of the tissue layers affected by the surgical procedure. Maternal morbidity from infections has been shown to be higher after caesarean section compared to the vaginal delivery. Objective of the research was to analyze the risk factors associated with surgical site infections after caesarean section.Methods: This was a cross sectional (affected/non affected) study approved by the institutional committee for ethics and research of the faculty of medicine and biomedical sciences. A total of 310 medical files were assessed, 62 files from patients with surgical site infections and 248 files from patients without any complications. The data was collected using a pretested questionnaire and analyzed using the statistical package for the social sciences (SPSS) software version 22.0. The Chi squared and the Fisher exact tests were used to assess homogeneity between the 2 groups. Odd ratio 95% confidence interval was used to assess the association between the variables.Results: The proportion of surgical site infections during the study was 1.81%. Factors associated with surgical site infections were premature rupture of membranes (OR: 2.065; 95% CI 1.051-4.05; p=0.035); the vertical midline incision (OR=5.26; 95% CI; 1.41-19.57; p=0.013) and a operation by a resident physician doctor (OR=1.98; 95% CI 1.09-3.59; p=0.02).Conclusions: A factors associated with surgical site infections after caesarean section are a premature rupture of membranes, vertical midline incision and the qualification of the practitioner

    3α-Hy­droxy­tirucalla-8,24-dien-21-oic acid

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    The title compound, C30H48O3, a triterpene isolated from the resin of canarium schweinfurthiiand, is an isomer of the previously reported triterpene 3α-hy­droxy­tirucalla-7,24-dien-21-oic acid [Mora et al. (2001 ▶). Acta Cryst. C57, 638–640], which crystallizes in the same trigonal space group. The title mol­ecule consists of four fused rings having chair, half-chair, half-chair and envelope conformations for rings A, B, C and D, respectively (steroid labelling). An intra­molecular C—H⋯O hydrogen bond generates an S(7) ring. In the crystal, mol­ecules are linked by O—H⋯O and C—H⋯O inter­actions, forming (001) sheets

    A cocrystal of 3α-hy­droxy­tirucalla-8,24-dien-21-oic acid and 3β-fluoro­tirucalla-7,24-dien-21-oic acid (0.897:0.103)

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    The title compound, 0.897C30H48O3.0.103C30H47O2F is a co-crystal of two triterpenes isolated from the resin of Canarium schweinfurthiiand Engl. Both triterpenes consists of four trans-fused rings having chair/half-chair/half-chair and envelope conformations. The mol­ecular conformations are stabilized by intra­molecular C—H⋯O hydrogen bonds, forming rings of S(7) graph-set motif. In the crystal, mol­ecules are linked by inter­molecular O—H⋯O and C—H⋯O inter­actions, forming sheets parallel to (001). All atoms. excepting the axially-oriented hydroxyl group in the major component and the equatorially-oriented fluorine atom in the minor component, are overlapping

    Crises epileptiques au cours de la toxoplasmose cerebrale chez les patients immunodeprimes au vih.

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    Objectif Décrire les caractéristiques des crises épileptiques au cours de la toxoplasmose cérébrale (TC) chez les patients immunodéprimés au VIH à l’Hôpital Général de Douala (HGD).Matériel méthodesIl s’agissait d’une étude descriptive rétrospective des cas de TC diagnostiquée entre janvier 2000 et décembre 2012. La prévalence, le type, la fréquence des crises épileptiques et les thérapeutiques antiépileptiques ont été étudiées. Les patients avec un antécédent de crises épileptiques étaient exclus. Le test de Khi-2 a été utilisé pour rechercher les facteurs associés à la survenue des crises épileptiques tandis que le test de Student a été utilisé pour comparer les moyennes. P < 0,05 était considéré comme statistiquement significatif.Résultats 146 patients étaient inclus avec 78 femmes pour un sex-ratio de 0,87 en faveur des femmes. L’âge moyen était de 39,38 ± 9,88 ans. Le taux de CD4 moyen était de 115,63 ± 142,70 éléments/ml. La prévalence des crises épileptiques était de 45,2% et 61% des épileptiques étaient répétées. Les crises épileptiques généralisées prédominaient avec 75,8%. Seuls la fièvre (p < 0,012), les céphalées (p < 0,004), le syndrome d’hypertension intracrânienne (p < 0,038), un taux de CD4 < 50/ mm3 (p < 0,02) et un taux d’hémoglobine < 10g/dl (p < 0,017) étaient statistiquement associés à la survenue des crises épileptiques. Un traitement antiépileptique était prescrit chez 43,2% des patients.Conclusion Les crises épileptiques sont fréquentes au cours de la toxoplasmose cérébrale. Elles peuvent se répéter et justifier d’un traitement antiépileptique.Mots clés : Toxoplasmose cérébrale, VIH, Crises épileptiques, Douala, Cameroun

    Targeting Antibody Responses to the Membrane Proximal External Region of the Envelope Glycoprotein of Human Immunodeficiency Virus

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    Although human immunodeficiency type 1 (HIV-1) infection induces strong antibody responses to the viral envelope glycoprotein (Env) only a few of these antibodies possess the capacity to neutralize a broad range of strains. The induction of such antibodies represents an important goal in the development of a preventive vaccine against the infection. Among the broadly neutralizing monoclonal antibodies discovered so far, three (2F5, Z13 and 4E10) target the short and hidden membrane proximal external region (MPER) of the gp41 transmembrane protein. Antibody responses to MPER are rarely observed in HIV-infected individuals or after immunization with Env immunogens. To initiate antibody responses to MPER in its membrane-embedded native conformation, we generated expression plasmids encoding the membrane-anchored ectodomain of gp41 with N-terminal deletions of various sizes. Following transfection of these plasmids, the MPER domains are displayed on the cell surface and incorporated into HIV virus like particles (VLP). Transfected cells displaying MPER mutants bound as efficiently to both 2F5 and 4E10 as cells transfected with a plasmid encoding full-length Env. Mice immunized with VLPs containing the MPER mutants produced MPER-specific antibodies, the levels of which could be increased by the trimerization of the displayed proteins as well as by a DNA prime-VLP boost immunization strategy. Although 2F5 competed for binding to MPER with antibodies in sera of some of the immunized mice, neutralizing activity could not be detected. Whether this is due to inefficient binding of the induced antibodies to MPER in the context of wild type Env or whether the overall MPER-specific antibody response induced by the MPER display mutants is too low to reveal neutralizing activity, remains to be determined

    Gender disparities in pulmonary hypertension at a tertiary centre in Cameroon

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    Background. Pulmonary hypertension (PH) is a potent cause of heart failure and has been little investigated in the African setting.Objective. To investigate the effects of gender on the clinical presentation, echocardiographic features and outcomes of patients with PH in Douala, Cameroon.Methods. A prospective cohort study was conducted from March 2012 to December 2013 as part of the Pan African Pulmonary Hypertension Cohort study. PH was diagnosed by echocardiography and defined as a right ventricular systolic pressure >35 mmHg in the absence of acute right heart failure. Patients were followed up for a maximum of 12 months for primary endpoint mortality.Results. In total, 130 patients with PH were recruited; 71 (54.6%) were women. The median age was 59.2 years for men and 58.3 years for women (p=0.76). Active smoking and alcohol use were more frequent in men than women (both p<0.001), but women had greater exposure to indoor cooking fumes than men (p<0.001). Previous tuberculosis infection (11.3% v. 1.7%) and S3 gallop rhythm (30.9% v. 11.9%) were more common in women (both p<0.03). Women had a significantly higher mean systolic blood pressure (134 mmHg v. 125 mmHg; p=0.04) and pulse pressure (53.8 mmHg v. 44.9 mmHg; p=0.01) and a lower mean haemoglobin concentration (10.4 g/dL v. 12.4 g/dL; p<0.05) compared with men. Echocardiographic left ventricular (LV) systolic dysfunction was more frequent in men: mean LV ejection fraction 42.6% v. 51.5% (p=0.01) and mean fractional shortening 21.4% v. 28.6% (p=0.01). The overall mortality rate was 20.3%, and rates were similar in the two groups (Kaplan-Meier log rank 1.1; p=0.30).Conclusions. Despite differences in baseline characteristics including cardiovascular risk factors, mortality rates on follow-up were similar in men and women in this study. However, these different baseline characteristics probably suggest differences in the pathogenesis of PH in men and women in our setting that need further investigation.

    Liposomal vaccines incorporating molecular adjuvants and intrastructural T-cell help promote the immunogenicity of HIV membrane-proximal external region peptides

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    An HIV vaccine capable of inducing high and durable levels of broadly neutralizing antibodies has thus far proven elusive. A promising antigen is the membrane-proximal external region (MPER) from gp41, a segment of the viral envelope recognized by a number of broadly neutralizing antibodies. Though an attractive vaccine target due to the linear nature of the epitope and its highly conserved sequence, MPER peptides are poorly immunogenic and may require display on membranes to achieve a physiological conformation matching the native virus. Here we systematically explored how the structure and composition of liposomes displaying MPER peptides impacts the strength and durability of humoral responses to this antigen as well as helper T-cell responses in mice. Administration of MPER peptides anchored to the surface of liposomes induced MPER-specific antibodies whereas MPER administered in oil-based emulsion adjuvants or alum did not, even when combined with Toll-like receptor agonists. High-titer IgG responses to liposomal MPER required the inclusion of molecular adjuvants such as monophosphoryl lipid A. Anti-MPER humoral responses were further enhanced by incorporating high-Tm lipids in the vesicle bilayer and optimizing the MPER density to a mean distance of ∼10–15 nm between peptides on the liposomes' surfaces. Encapsulation of helper epitopes within the vesicles allowed efficient “intrastructural” T-cell help, which promoted IgG responses to MPER while minimizing competing B-cell responses against the helper sequence. These results define several key properties of liposome formulations that promote durable, high-titer antibody responses against MPER peptides, which will be a prerequisite for a successful MPER-targeting vaccine.Bill & Melinda Gates FoundationNational Institutes of Health (U.S.) (AI091693

    Ethnoknowledge of medicinal and mystical plants used by healers in Juazeiro do Norte, Ceará, Northeast Brazil

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    154-166The aim of this study was to investigate the use of medicinal plants by healers in Juazeiro do Norte, Northeast Brazil, as well as to understand their role in prayer/healing practices. 30 residents from 20 neighborhoods, 18 urban neighborhoods and 2 randomly selected rural locations, were interviewed using a sample method known as "snowball", with two pilot interviews being initially conducted, where for greater method reliability and for the analysis of the importance attributed to the plants by the respondents, a calculation to determine their Relative Importance (RI) index was used. The results indicate the use of 60 species distributed across 34 families. The most representative families were: Fabaceae (7), Lamiaceae (6) and Asteraceae (5), where 10 species (eight exotic and two native) obtained a Relative Importance (RI>1): Ruta graveolens L. (1.47), Vernonia condensata Baker (1.47), Piper aduncun L. (1.44), Mentha spicata L. (1.33), Myracrodruon urundeuva Allemão (1.3), Psidium guajava L. (1.19), Hymenaea stignocarpa Mart. ex. Hayne (1.15), Lippia alba (Mil.) (1.11), Leonotis nepetaefolia (L.) R. Br. (1.08) and Cymbopogon citratus (D.C.) Stapf (1.01). The aforementioned species are acquired from backyards (50%), open markets (33.3%) or from surrounding scrubs (16.6%). Indications included usage for 11 body systems, with 36 species (60%) being indicated for the treatment of the digestive system and 15 (25%) for the treatment of diseases of the female reproductive system. Nine species (15%) were indicated for ritualistic purposes (prayer/healing). With this, the importance of the Healer figure in several municipal districts was observed, a tradition that remains alive, despite the need for greater transmission and assimilation to upcoming generations
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