286 research outputs found

    Significance of the characteristic roots of linearized econometric models

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    This paper shows how to compute asymptotic standard errors of the characteristic roots of a nonlinear econometric model. The system of simultaneous equations is linearized in the neighborhood of a given point, then characteristic roots and related standard errors are computed.Nonlinear econometric models; characteristic roots; eigenvalues; asymptotic standard errors

    Cytotoxic effect of hemin in colonic epithelial cell line: Involvement of 18kDa translocator protein (TSPO).

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    Aims The aim of this study is to investigate the effect of hemin in colonic epithelial cells (Caco-2) cell proliferation and if this effect was due to a direct modulation of 18-kDa translocator protein (TSPO) and/or heme oxygenase type 1 (HO-1). Main methods The main methods are as follow: cell proliferation and cell cytotoxic assays on Caco-2 cell lines treated with hemin in the presence or not of 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxamide (PK 11195) and Sn-protoporphyrin IX (Sn-PPIX), and immunoblotting for TSPO and HO-1 protein analysis, siRNA directed against TSPO. Key findings Hemin was shown to be toxic for the Caco-2 cell line in a concentration and time dependent manner. Although hemin was able to induce HO-1 in a dose dependent manner, a specific HO-1 inhibitor, Sn-PPIX, was unable to interfere with the effect of hemin on Caco-2 cells. Instead, PK 11195, a specific TSPO ligand, was able to counteract the effect of hemin, suggesting an important role of TSPO in the hemin activity. Cell viability assay further confirms the high cytotoxic effects exerted by hemin on Caco-2 cells expressing TSPO compared to the siRNA-TSPO targeted cells. In addition, hemin was able to decrease significantly the TSPO protein density in a dose dependent manner after 24 h of incubation. Significance The interaction and the consecutive down regulation of TSPO by hemin played an important role in the control of Caco-2 cell viability. The presented data suggest that TSPO might contribute to protect cells from potential toxic compounds such as free tetrapyrroles, candidating this receptor as a survival receptor protein

    Characterization of biocompatible scaffolds manufactured by fused filament fabrication of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate

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    We characterize poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) scaffolds for tissue repair and regeneration, manufactured by three-dimensional fused filament fabrication (FFF). PHBH belongs to the class of polyhydroxyalkanoates with interesting biodegradable and biocompatible capabilities, especially attractive for tissue engineering. Equally, FFF stands as a promising manufacturing technology for the production of custom-designed scaffolds. We address thermal, rheological and cytotoxicity properties of PHBH, placing special emphasis on the mechanical response of the printed material in a wide deformation range. Indeed, effective mechanical properties are assessed in both the linear and nonlinear regime. To warrant uniqueness of the material parameters, these are measured directly through digital image correlation, both in tension and compression, while experimental data fitting of finite-element analyses is only adopted for the determination of the second invariant coefficient in the nonlinear regime. Mechanical data are clearly porosity dependent, and they are given for both the cubic and the honeycomb infill pattern. Local strain spikes due to the presence of defects are observed and measured: those falling in the range 70\u2013100% lead to macro-crack development and, ultimately, to failure. Results suggest the significant potential attached to FFF printing of PHBH for customizable medical devices which are biocompatible and mechanically resilient

    Antiproliferative effects of Ceratonia siliqua L. on mouse hepatocellular carcinoma cell line

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    Extracts from pods and leaves of carob (Ceratonia siliqua L.) were tested for their ability to inhibit cell proliferation of mouse hepatocellular carcinoma cell line (T1). The two extracts showed a marked alteration of T1 cell proliferation in a dose-related fashion reaching the maximal effect at 1 mg/ml. Moreover, we demonstrated that leaf and pod extracts were able to induce apoptosis in T1 cell lines after 24-h treatment mediating a direct activation of the caspase 3 pathway. HPLC analysis revealed the presence of gallic acid, epigallocatechin-3-gallate and (-) epi catechin - 3 -gallate in pod and leaf extracts, compounds well known to exert antiproliferative effects. Their concentration reached 6.28 mg/g in carob leaves and 1.36 mg/g in carob pods extract. The discovery that carob pod and leaf extracts contained antiproliferative agents could be of practical importance in the development of functional foods and/or chemopreventive drugs

    Cannabis sativa L. and Nonpsychoactive Cannabinoids: Their Chemistry and Role against Oxidative Stress, Inflammation, and Cancer

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    In the last decades, a lot of attention has been paid to the compounds present in medicinal Cannabis sativa L., such as \u3949-Tetrahydrocannabinol (\u3949-THC) and cannabidiol (CBD), and their effects on inflammation and cancer-related pain. The National Cancer Institute (NCI) currently recognizes medicinal C. sativa as an effective treatment for providing relief in a number of symptoms associated with cancer, including pain, loss of appetite, nausea and vomiting, and anxiety. Several studies have described CBD as a multitarget molecule, acting as an adaptogen, and as a modulator, in different ways, depending on the type and location of disequilibrium both in the brain and in the body, mainly interacting with specific receptor proteins CB1 and CB2. CBD is present in both medicinal and fibre-Type C. sativa plants, but, unlike \u3949-THC, it is completely nonpsychoactive. Fibre-Type C. sativa (hemp) differs from medicinal C. sativa, since it contains only few levels of \u3949-THC and high levels of CBD and related nonpsychoactive compounds. In recent years, a number of preclinical researches have been focused on the role of CBD as an anticancer molecule, suggesting CBD (and CBD-like molecules present in the hemp extract) as a possible candidate for future clinical trials. CBD has been found to possess antioxidant activity in many studies, thus suggesting a possible role in the prevention of both neurodegenerative and cardiovascular diseases. In animal models, CBD has been shown to inhibit the progression of several cancer types. Moreover, it has been found that coadministration of CBD and \u3949-THC, followed by radiation therapy, causes an increase of autophagy and apoptosis in cancer cells. In addition, CBD is able to inhibit cell proliferation and to increase apoptosis in different types of cancer models. These activities seem to involve also alternative pathways, such as the interactions with TRPV and GRP55 receptor complexes. Moreover, the finding that the acidic precursor of CBD (cannabidiolic acid, CBDA) is able to inhibit the migration of breast cancer cells and to downregulate the proto-oncogene c-fos and the cyclooxygenase-2 (COX-2) highlights the possibility that CBDA might act on a common pathway of inflammation and cancer mechanisms, which might be responsible for its anticancer activity. In the light of all these findings, in this review we explore the effects and the molecular mechanisms of CBD on inflammation and cancer processes, highlighting also the role of minor cannabinoids and noncannabinoids constituents of \u3949-THC deprived hemp

    Efficient double glycoconjugation to naturalize high molecular weight disperse dyes

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    Commercially available Disperse Orange 29 (1a) and Disperse Red 1 (2a) were elaborated to glycoconjugated species, following a new version of a previously-described ‘naturalisation’ procedure. Glutamic acid was chosen to achieve a double glycoconjugation, which is essential to give to the original disperse dye a water solubility suitable for reaching optimal dyeing conditions. UV–vis plot of the ‘naturalised’ species showed negligible differences when compared to those of the commercial dye

    Significance of the characteristic roots of linearized econometric models

    Get PDF
    This paper shows how to compute asymptotic standard errors of the characteristic roots of a nonlinear econometric model. The system of simultaneous equations is linearized in the neighborhood of a given point, then characteristic roots and related standard errors are computed
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