1,720,962 research outputs found

    Secular trends in growth of African Pygmies and Bantu

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    OBJECTIVE: The aim of this study was to investigate whether a secular trend in growth occurred during the last century in Pygmies from Cameroon (West Pygmies) and in Bantu rural farmers, the latter being studied to serve as controls.-DESIGN: The evolution in height of West Pygmies and Bantu farmers from 1911 to 2006 was evaluated using data from the literature as well as data gathered by our research team during an expedition to Cameroon in 2006. RESULTS: During the last century, no secular trend in west Pygmies is apparent, as height changed from 151 cm to 155 cm in males and from 143 cm to 146 cm in females. A small though significant (p=0.026), increment (about 2 cm) was observed only in female subjects during the last ten years. By contrast, Bantu heights show a significant change from 1943 to 2006 for both males (from 159 cm to 172 cm; p=0.025) and females (from 148 cm to 160 cm; p=0.029). CONCLUSIONS: Over the last century, the Bantu population exhibited a significant secular trend for height, whereas West Pygmies did not increase their linear growth. The lack of secular trend in Pygmies possibly suggests that their stature reflects adaptation to the forest lifestyle. We may hypothesize that not only environmental but epigenetic factors have also contributed to their growth potential

    Study of Uptake Mechanisms of Halloysite Nanotubes in Different Cell Lines

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    Giuseppa Biddeci,1,2 Gaetano Spinelli,1 Marina Massaro,2 Serena Riela,2 Paola Bonaccorsi,3 Anna Barattucci,3 Francesco Di Blasi1 1Institute for Innovation and Biomedical Research (IRIB), CNR, Palermo, 90146, Italy; 2Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), Sect. Chemistry, University of Palermo, Palermo, 90128, Italy; 3Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, 98158, ItalyCorrespondence: Francesco Di BlasiInstitute for Innovation and Biomedical Research (IRIB), CNR, Via Ugo La Malfa 153, Palermo, 90146, ItalyTel +39 0916809514Email [email protected]: Halloysite nanotubes (HNTs) are a natural aluminosilicate clay with a chemical formula of Al2Si2O5(OH)4×nH2O and a hollow tubular structure. Due to their peculiar structure, HNTs can play an important role as a drug carrier system. Currently, the mechanism by which HNTs are internalized into living cells, and what is the transport pathway, is still unclear. Therefore, this study aimed at establishing the in vitro mechanism by which halloysite nanotubes could be internalized, using phagocytic and non-phagocytic cell lines as models.Methods: The HNT/CURBO hybrid system, where a fluorescent probe (CURBO) is confined in the HNT lumen, has been used as a model to study the transport pathway mechanisms of HNTs. The cytocompatibility of HNT/CURBO on cell lines model was investigated by MTS assay. In order to identify the internalization pathway involved in the cellular uptake, we performed various endocytosis-inhibiting studies, and we used fluorescence microscopy to verify the nanomaterial internalization by cells. We evaluated the haemolytic effect of HNT/CURBO placed in contact with human red blood cells (HRBCs), by reading the absorbance value of the supernatant at 570 nm.Results: The HNT/CURBO is highly biocompatible and does not have an appreciable haemolytic effect. The results of the inhibition tests have shown that the internalization process of nanotubes occurs in an energy-dependent manner in both the investigated cell lines, although they have different characteristics. In particular, in non-phagocytic cells, clathrin-dependent and independent endocytosis are involved. In phagocytic cells, in addition to phagocytosis and clathrin-dependent endocytosis, microtubules also participate in the halloysite cellular trafficking. Upon internalization by cells, HNT/CURBO is localized in the cytoplasmic area, particularly in the perinuclear region.Conclusion: Understanding the cellular transport pathways of HNTs can help in the rational design of novel drug delivery systems and can be of great value for their applications in biotechnology.Keywords: halloysite nanotubes, endocytic pathway, cellular internalization, biocompatibility, hemocompatibilit

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed

    Variations on the Author

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    “Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship

    Appropriate Similarity Measures for Author Cocitation Analysis

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    We provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis

    Mucormycosis with peculiar aortic involvement in a child with acute lymphoblastic leukemia

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    Among fungal infection, mucormycosis is a rare but severe etiology in immunocompromised patients. Lung and sinus are the usual sites; the involvement of blood vessels is also described. The diagnosis is a real challenge, because blood tests (galactomannan, beta-D-glucan) are negative and the only diagnostic tool is usually the biopsy of the affected zone. Aortitis is rare and usually caused by bacterial infection, fungal etiology is unusual and only episodic cases are reported in literature. Medical therapy alone is usually not sufficient and debilitating surgical intervention is required. We report the case of a child affected by B precursor acute lymphoblastic leukemia, presenting a systemic fungal infection complicated by aortitis, probably due to Mucor. The patient developed fever and pneumonia during the Induction phase of chemotherapy. At the beginning, the infection was treated as bacterial and the diagnosis of Mucor infection was possible only after surgical intervention with histological analysis. Medical therapy (antifungal) was not sufficient alone to cure the infection and an urgent surgical intervention was required. This case underlines the challenge in the diagnosis of mucomycosis, that should be suspected in case of prolonged fever during aplasia, not responding to standard antibiotic and antifungal therapies. Mucor infection often require a combined intervention, both medical and surgical to cure the infection

    Halloysite nanotubes loaded with peppermint essential oil as filler for functional biopolymer film

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    The purpose of this paper is to show how a functional bionanocomposite film with both antioxidant and antimicrobial activities was successfully prepared by the filling of a pectin matrix with modified Halloysite nanotubes (HNT) containing the essential peppermint oil (PO). Firstly, HNT surfaces were functionalized with cucurbit[6]uril (CB[6]) molecules with the aim to enhance the affinity of the nanofiller towards PO, which was estimated by means of HPLC experiments. The HNT/CB[6] hybrid was characterized by several methods (thermogravimetry, FT-IR spectroscopy and scanning electron microscopy) highlighting the influence of the supramolecular interactions on the composition, thermal behavior and morphology of the filler. Then, a pectin + HNT/CB[6] biofilm was prepared by the use of the casting method under specific experimental conditions in order to favor the entrapment of the volatile PO into the nanocomposite structure. Water contact angle measurements, thermogravimetry and tensile tests evidenced the effects of the modified filler on the thermo-mechanical and wettability properties of pectin, which were correlated to the microscopic structure of the biocomposite film. In addition, PO release in food simulant solvent was investigated at different temperatures (4 and 25 °C), whereas the antioxidant activity of the nanocomposite film was estimated using the DPPH method. Finally, we studied the in vitro antibacterial activity of the biofilm against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive), which were isolated by beef and cow milk, respectively. These experiments were carried out at specific temperatures (4, 37 and 65 °C) that can be useful for a multi-step food conservation. This paper puts forwards an easy strategy to prepare a functional sustainable edible film with thermo-sensitive antioxidant/antimicrobial activity
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