Hypericum sp.: essential oil composition and biological activities

Phytochemical composition of Hypericum genus has been investigated for many years. In the recent past, studies on the essential oils (EO) of this genus have been progressing and many of them have reported interesting biological activities. Variations in the EO composition of Hypericum species influenced by seasonal variation, geographic distribution, phenological cycle and type of the organ in which EO are produced and/or accumulated have also been reported. Although many reviews attributed to the characterization as well as biological activities of H. perforatum crude extracts have been published, no review has been published on the EO composition and biological activities of Hypericum species until recently (Crockett in Nat Prod Commun 5(9):1493–1506, 2010; Bertoli et al. in Global Sci Books 5:29–47, 2011). In this article, we summarize and update information regarding the composition and biological activities of Hypericum species EO. Based on experimental work carried out in our laboratory we also mention possible biotechnology approaches envisaging EO improvement of some species of the genus.Fundação para a Ciência e a Tecnologia (FCT) - project PTDC/AGR AAM/70418/2006, SFRH/BD/ 13283/2003

Model Validation of an Empirical Photovoltaic Thermal (PV/T) Collector

AbstractWithin solar energy technologies, the hybrid photovoltaic–thermal (PV/T) systems offer an attractive option because the absorbed solar radiation is converted into thermal and electrical energy (the conversion can be done separately or simultaneously). In this paper, an attempt is made to investigate the thermal and electrical performance of a solar photovoltaic thermal collector. A detailed thermal model is developed to calculate the thermal parameters of a typical PV/T collector. The thermal parameters of this collector include solar cell temperature, outlet water temperature, thermal efficiency and useful thermal energy. Some corrections are done on heat loss coefficients in order to improve the thermal model of a PV/T collector. A computer simulation program is developed in order to calculate the thermal and electrical parameters of a PV/T collector. The absorber is realized with the galvanized iron of high quality, allowing a good transfer of heat with lower cost compared to copper. This PVT has the advantage of its simple implementation and its low cost compared to other configurations. The results of numerical simulation are in good agreement with the experimental measurements noted in the previous literature. It is observed that the thermal simulation results obtained in this paper is more precise than the one given by the previous literature. It is also found that the thermal efficiency of PV/T collector is about 54.51% in the mode of water heat exchanger, and 16.24% in air heat extraction, the electrical efficiency is 11.12%, for a sample climatic, operating and design parameters

Comparison of Immunoblotting, Calculation of the Goldmann-Witmer Coefficient, and Real-Time PCR Using Aqueous Humor Samples for Diagnosis of Ocular Toxoplasmosis▿ †

We compared three biological methods for the diagnosis of ocular toxoplasmosis (OT). Paired aqueous humor and serum samples from 34 patients with OT and from 76 patients with other ocular disorders were analyzed by three methods: immunoblotting or Western blotting (WB), the calculation of the Goldmann-Witmer coefficient (GWC), and PCR. WB and GWC each revealed the intraocular production of specific anti-Toxoplasma immunoglobulin G in 81% of samples (30 of 37). PCR detected toxoplasmic DNA in 38% of samples (13 of 34). Nine of the 13 PCR-positive patients were immunocompetent. Combining the techniques significantly improved the diagnostic sensitivity, to 92% for the GWC-WB combination, 90% for the WB-PCR combination, and 93% for the GWC-PCR combination. The combination of all three techniques improved the sensitivity to 97%

Caractérisation et validation multicentrique d'une gamme standard pour la détection de Toxoplasma gondii destinée aux techniques d'amplification de l'AND.

International audienc