192 research outputs found

    GNSS-Based Attitude Determination Techniques - A Comprehensive Literature Survey

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    GNSS-based Attitude Determination (AD) of a mobile object using the readings of the Global Navigation Satellite Systems (GNSS) is an active area of research. Numerous attitude determination methods have been developed lately by making use of various sensors. However, the last two decades have witnessed an accelerated growth in research related to GNSS-based navigational equipment as a reliable and competitive device for determining the attitude of any outdoor moving object using data demodulated from GNSS signals. Because of constantly increasing number of GNSS-based AD methods, algorithms, and techniques, introduced in scientific papers worldwide, the problem of choosing an appropriate approach, that is optimal for the given application, operational environment, and limited financial funding becomes quite a challenging task. The work presents an extensive literature survey of the methods mentioned above which are classified in many different categories. The main aim of this survey is to help researchers and developers in the field of GNSS applications to understand pros and cons of the current state of the art methods and their computational efficiency, the scope of use and accuracy of the angular determination.https://doi.org/10.1109/ACCESS.2020.297008

    In vitro differentiation of human umbilical cord blood mesenchymal stem cells into functioning hepatocytes

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    Mesenchymal stem cells (MSCs) were isolated by gradient density centrifugation from umbilical cord blood. Spindle-shaped adherent cells were permitted to grow to 70% confluence in primary culture media which was reached by day 12. Induction of differentiation started by culturing cells with differentiation medium containing FGF-4 and HGF. Under hepatogenic conditions few cuboidal cells appeared in culture on day 7. From day 21 to day 28, most of cells became small and round. The control negative cells cultured in serum free media showed fibroblast-like morphology. Urea production and protein secretion by the differentiated hepatocyte-like cells were detected on day 21 and increased on day 28. Protein was significantly increased in comparison with control by day 28. The cells became positive for AFP at day 7 and positive cells could still be detected at days 21 and 28. The cells in the control group were stained negative for AFP. The cells expressed albumin gene at the 14th day that became markedly increased at the 28th day of culture with HGF and FGF-4. No albumin expression was observed in the 7th day sample and the control. This study demonstrated that UCB-derived MSCs had the ability to differentiate into functioning hepatocyte-like cells starting from the 7th day after culturing under hepatogenic conditions and became well functioning at days 21 and 28. These data indicated that UCB-derived MSCs can be a promising source of cell therapy for intractable liver diseases.Keywords: Umbilical cord blood; Mesenchymal stem cells; Culture; Hepatocytes; HGF; FGF-

    Antifungal Activities of Extracts from Selected Lebanese Wild Plants against Plant Pathogenic Fungi

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    Extracts of nine plant species growing wild in Lebanon were tested for their efficacy against seven plant pathogenic fungi: Botrytis cinerea, Alternaria solani, Penicillium sp., Cladosporium sp., Fusarium oxysporum f. sp. melonis, Rhizoctonia solani and Sphaerotheca cucurbitae. Extracts of three of the plants, Origanum syriacum, Micromeria nervosa and Plumbago maritima, showed the highest levels of in vitro activity against spore germination and mycelial growth of the fungi tested. Inula viscosa showed high activity against spore germination but only moderate activity against mycelial growth. The other five plant species tested Calamintha origanifolia, Micromeria juliana, Ruta sp., Sideritis pullulans and Urginea maritima showed only moderate to low activity against these fungi. Preventive sprays with extracts of O. syriacum, M. nervosa, P. maritima and I. viscosa, applied at concentrations ranging between 4 and 8% to squash and cucumber seedlings, gave efficient protection against gray mold caused by B. cinerea and powdery mildew caused by S. cucurbitae. However, these extracts did not control green mold of citrus fruits caused by Penicillium sp. Thin layer chromatography revealed three inhibitory bands in extracts of O. syriacum, two in I. viscosa and only one in each of the other plants tested: M. nervosa, P. maritima, C. origanifolia and Ruta sp

    'Candidatus Phytoplasma phoenicium’ associated with almond witches’-broom disease: from draft genome to genetic diversity among strain populations

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    BACKGROUND: Almond witches'-broom (AlmWB), a devastating disease of almond, peach and nectarine in Lebanon, is associated with 'Candidatus Phytoplasma phoenicium'. In the present study, we generated a draft genome sequence of 'Ca. P. phoenicium' strain SA213, representative of phytoplasma strain populations from different host plants, and determined the genetic diversity among phytoplasma strain populations by phylogenetic analyses of 16S rRNA, groEL, tufB and inmp gene sequences. RESULTS: Sequence-based typing and phylogenetic analysis of the gene inmp, coding an integral membrane protein, distinguished AlmWB-associated phytoplasma strains originating from diverse host plants, whereas their 16S rRNA, tufB and groEL genes shared 100 % sequence identity. Moreover, dN/dS analysis indicated positive selection acting on inmp gene. Additionally, the analysis of 'Ca. P. phoenicium' draft genome revealed the presence of integral membrane proteins and effector-like proteins and potential candidates for interaction with hosts. One of the integral membrane proteins was predicted as BI-1, an inhibitor of apoptosis-promoting Bax factor. Bioinformatics analyses revealed the presence of putative BI-1 in draft and complete genomes of other 'Ca. Phytoplasma' species. CONCLUSION: The genetic diversity within 'Ca. P. phoenicium' strain populations in Lebanon suggested that AlmWB disease could be associated with phytoplasma strains derived from the adaptation of an original strain to diverse hosts. Moreover, the identification of a putative inhibitor of apoptosis-promoting Bax factor (BI-1) in 'Ca. P. phoenicium' draft genome and within genomes of other 'Ca. Phytoplasma' species suggested its potential role as a phytoplasma fitness-increasing factor by modification of the host-defense response

    Recovery-based staff training intervention within mental health rehabilitation units: A two-stage analysis using realistic evaluation principles and framework approach

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    Background - Long-term change in recovery-based practice in mental health rehabilitation is a research priority. Methods - We used a qualitative case study analysis using a blend of traditional 'framework' analysis and 'realist' realist principles toapproaches to carry-out an evaluation of a recovery-focused staff training intervention within three purposively selected mental health rehabilitation units. We tried to ensure the validity of the data by using triangulation of multiple data sources and were collected using different methods. Results - We found that organisational culture and embedding of a change management programme in routine practice were reported as key influences to sustain any change in practice. The qualitative study generated 10 recommendations on how to achieve long-term change in practice including dealing with pre-existing organisational and cultural problems in NHS units. Conclusions - We would propose that a recovery-focused staff training intervention requires leadership, continuity and integration with existing change management programme for long-term change. The intervention must be embedded into routine practice for sustainability
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