Effect of Forest Biomass Pretreatment on Essential Oil Yield and Properties

Essential oils (EOs) are natural and economically valuable aromatic compounds obtained from a variety of crops and trees, including forest trees, which have different therapeutic and biological activities. This project aims to assess the impact of different residual forest biomass pretreatments on the yield and the properties of EOs, including their antibacterial and antioxidant characteristics. Forest biomass from black spruce (BS, Picea mariana Mill.), balsam fir (BF, Abies balsamea), and jack pine (JP, Pinus banksiana Lamb.) was processed mechanically by (i) shredding, (ii) grinding, (iii) pelletizing, and (iv) bundling. EOs were then extracted by hydro- and steam distillation. The densification into bundles was found to improve EOs yield compared to the other residual forest biomass pretreatments. For example, the yield of bundled BF was improved by 68%, 83%, and 93% compared to shredded, ground, and granulated biomass, respectively. The highest yield was obtained when densification into bundles was combined with extraction through hydrodistillation. As for EOs' chemical composition, JP had the highest polyphenol content and consequently the greatest antioxidant activity. EOs derived from BS inhibited the growth of Grampositive Staphylococcus aureus bacteria and Gram-negative Salmonella typhimurium and Escherichia coli bacteria. The densification of forest biomass into bundles did not affect the antioxidant capacity or the antibacterial activity of EOs, thereby preserving both properties. Thus, the pretreatment of forest biomass residue could have an impact on the volume and the transport costs and therefore improve the bioproducts market and the bioeconomy in Canada

Effect of particle size, coupling agent and DDGS additions on Paulownia wood polypropylene composites

Studies aimed at improving the tensile, flexural, impact, thermal, and physical characteristics of wood–plastic composites composed of Paulownia wood flour derived from 36-month-old trees blended with polypropylene were conducted. Composites of 25% and 40% w/w of Paulownia wood were produced by twin-screw compounding and injection molding. Composites containing 0–10% by weight of maleated polypropylene were evaluated and an optimum maleated polypropylene concentration determined, i.e., 5%. The particle size distribution of Paulownia wood filler is shown to have an effect on the tensile and flexural properties of the composites. Novel combination composites of dried distiller’s grain with solubles mixed with Paulownia wood (up to 40% w/w) were produced and their properties evaluated. Depending on the composite tested, soaking composites for 872 h alters mechanical properties and causes weight gain

Molecular analysis of HBV genotypes and subgenotypes in the Central-East region of Tunisia

<p>Abstract</p> <p>Background</p> <p>In Tunisia, country of intermediate endemicity for Hepatitis B virus (HBV) infection, most molecular studies on the virus have been carried out in the North of the country and little is known about other regions. The aim of this study was to determine HBV genotype and subgenotypes in Central-East Tunisia. A total of 217 HBs antigen positive patients were enrolled and determination of genotype was investigated in 130 patients with detectable HBV DNA. HBV genotyping methods were: PCR-RFLP on the pre-S region, a PCR using type-specific primers in the S region (TSP-PCR) and partial sequencing in the pre-S region.</p> <p>Results</p> <p>Three genotypes (D, B and A) were detected by the PCR-RFLP method and two (D and A) with the TSP-PCR method, the concordance between the two methods was 93%. Sequencing and phylogenetic analysis of 32 strains, retrieved the same genotype (D and A) for samples with concordant results and genotype D for samples with discordant results. The sequences of discordant genotypes had a restriction site in the pre-S gene which led to erroneous result by the PCR-RFLP method. Thus, prevalence of genotype D and A was 96% and 4%, respectively. Phylogenetic analysis showed the predominance of two subgenotypes D1 (55%) and D7 (41%). Only one strain clustered with D3 subgenotype (3%).</p> <p>Conclusions</p> <p>Predominance of subgenotype D7 appears to occur in northern regions of Africa with transition to subgenotype D1 in the East of the continent. HBV genetic variability may lead to wrong results in rapid genotyping methods and sequence analysis is needed to clarify atypical results.</p

Rôle du virus Toscana dans les infections neuroméningées en Tunisie

International audienceOBJECTIVES: To detect the presence of Toscana virus (TOSV) circulation in Tunisia and to study its role in viral meningo-encephalitis.PATIENTS AND METHODS: A total of 315 (167 sera and 178 cerobrospinal fluid [CSF]) samples was investigated. These samples are colleted from Tunisian patients with neurological diseases during the period between January 2003 and December 2009. All samples were tested negative for enterovirus, Herpes Simplex virus and West Nile virus. Detection for IgM and IgG specific to TOSV was done by ELISA tests.RESULTS: Specific IgM for TOSV were detected in 10 % of patients with neurological diseases (31 cases). These recent infections were distributed throughout the study period and predominated during summer and automn. Patients were originated, in the majority from the coastal region. IgG were isolated in 22 cases (7 %) corresponding to previous infection.CONCLUSION: This is the first report of TOSV circulating in Tunisia and its frequent implication in neurological diseases. These results incited to include TOSV as one of the viral etiologies to target in the diagnosis of viral meningitis and encephalitis in the country.But de l’étude : Rechercher les témoins de l’éventuelle présence du virus Toscana (TOSV) en Tunisie et étudier son implication dans les infections neuroméningées dans le pays.Patients et méthodes : Au total, 167 prélèvements de sérums et 178 LCR collectés chez 315 patients, hospitalisés pour méningite ou méningo-encéphalite virale, ont été investigués. Ces prélèvements ont été collectés durant la période allant de janvier 2003 à décembre 2009 et ont été préalablement testés négatifs vis-à-vis des entérovirus, virus Herpes Simplex de type 1 et virus West Nile. La recherche des IgM et IgG spécifiques du TOSV a été faite par Elisa indirecte.Résultats : Dix pour cent (n = 31) de ces prélèvements se sont révélés positifs en IgM anti-TOSV ; ces cas sont répartis de façon homogène sur toute la période étudiée. Une infection ancienne a été détectée dans 7 % des cas (n = 22). L’infection neuroméningée à TOSV est plus fréquente chez l’homme (20/11), en période estivo-automnale et en zone côtière.Conclusion : Il s’agit là d’une première étude rapportant la circulation du TOSV en Tunisie et son rôle non négligeable dans les infections neuroméningées. Ces résultats nous incitent à une surveillance régulière avec recherche systématique d’une infection à TOSV devant toute atteinte neurologique. Il serait même intéressant de généraliser la recherche du TOSV à d’autres tableaux cliniques où il a été également impliqué comme le syndrome fébrile aigu ou le syndrome grippal type « grippe d’été »

BAFF is elevated in serum of patients with psoriasis: association with disease activity

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Effet de la direction d'injection lors de l'élaboration de polypropylène renforcé avec de la farine de bois d'olivier: propriétés ultrasonores et morphologiques

Proceedings of the Second International Conference on Acoustics and Vibration (ICAV2018), March 19-21, 2018, Hammamet, TunisiaInternational audienceAlthough the anisotropy of wood fibers is reasonably well established, the anisotropy of injection molded wood fiber composites is not well understood. For this, fiber distribution is an important parameter in determining the properties of the composite. This work investigates the application of ultrasonic testing in evaluating natural fiber thermoplastic composites reinforced with olive wood flour (OWF). The characterization of sound propagation speed in the composite is intended to be a tool for evaluating the bio-composite namely fiber distribution and the effects of the direction of injection during the elaboration of the composite. The quality of fiber distribution homogeneity can be assessed by mapping the returning signals of the emitted longitudinal ultrasonic wave. This study presents the measured sound speeds for a composite system of OWF and polypropylene (PP) using immersion measurements. It is known that the longitudinal wave velocity is a function of the material property, which in turn is a function of fiber content and adhesion efficiency. Therefore, the aim of this work is to study the feasibility of using the ultrasonic longitudinal sound wave and the time of flight TOF instead of the morphological analysis with the scanning electron microscope, which is much more expensive and complicate