76 research outputs found
Design of Scaffolds Based on Zinc-Modified Marine Collagen and Bilberry Leaves Extract-Loaded Silica Nanoparticles as Wound Dressings
No full textMihaela Deaconu,1,2 Ana-Maria Prelipcean,3 Ana-Maria Brezoiu,2 Raul-Augustin Mitran,4 Ana-Maria Seciu-Grama,2 Cristian Matei,2 Daniela Berger2 1CAMPUS Research Institute, National University of Science and Technology Politehnica Bucharest, Bucharest, 060042, Romania; 2Faculty of Chemical Engineering and Biotechnologies, National University of Science and Technology Politehnica Bucharest, Bucharest, 011061, Romania; 3National Institute of R&D for Biological Sciences, Bucharest, 060031, Romania; 4‘Ilie Murgulescu’ Institute of Physical Chemistry, Romanian Academy, Bucharest, 060021, RomaniaCorrespondence: Daniela Berger, Faculty of Chemical Engineering and Biotechnologies, National University of Science and Technology Politehnica Bucharest, 1-7 Polizu Street, Bucharest, 011061, Romania, Email [email protected]: In this study, wound dressings were designed using zinc-modified marine collagen porous scaffold as host for wild bilberry (WB) leaves extract immobilized in functionalized mesoporous silica nanoparticles (MSN). These new composites were developed as an alternative to conventional wound dressings. In addition to the antibacterial activity of classic antibiotics, a polyphenolic extract could act as an antioxidant and/or an anti-inflammatory agent as well.Methods: Wild bilberry leaves extract was prepared by ultrasound-assisted extraction in ethanol and its properties were evaluated by UV-Vis spectroscopy (radical scavenging activity, total amount of polyphenols, flavonoids, anthocyanins, and condensed tannins). The extract components were identified by HPLC, and the antidiabetic properties of the extract were evaluated via α-glucosidase inhibitory activity. Spherical MSN were modified with propionic acid or proline moieties by post-synthesis method and used as carriers for the WB leaves extract. The textural and structural features of functionalized MSN were assessed by nitrogen adsorption/desorption isotherms, small-angle XRD, SEM, TEM, and FTIR spectroscopy. The composite porous scaffolds were prepared by freeze drying of the zinc-modified collagen suspension containing WB extract loaded silica nanoparticles.Results: The properties of the new composites demonstrated enhanced properties in terms of thermal stability of the zinc-collagen scaffold, without altering the protein conformation, and stimulation of NCTC fibroblasts mobility. The results of the scratch assay showed contributions of both zinc ions from collagen and the polyphenolic extract incorporated in functionalized silica in the wound healing process. The extract encapsulated in functionalized MSN proved enhanced biological activities compared to the extract alone: better inhibition of P. aeruginosa and S. aureus strains, higher biocompatibility on HaCaT keratinocytes, and anti-inflammatory potential demonstrated by reduced IL-1β and TNF-α levels.Conclusion: The experimental data shows that the novel composites can be used for the development of effective wound dressings. Keywords: mesoporous silica carrier, bilberry leaves extract, marine collagen, antibacterial composite, anti-inflammatory activit
Creativitatea şi ciclul de viaţă a produselor
No full textThe concept of life cycle stages has a significant impact upon business strategy and performance.�creativity, product life cycle, new product development process
The relationship between the audit committee
No full textAudit committees, governance type or otherwise, are a less common feature in EU Member States, where only few countries have extended audit committees or “governance” or similar such committees .
Audit committees in the private sector focus on ensuring the reliability and the internal and external reporting, and therefore on the internal and external audit, the quality of internal control systems and risk management processes. For many countries applying this type of public sector audit committee may be too sophisticated, because there are no preconditions for its existence. The existence of audit committees does not automatically mean that organizations function properly and have no governance, internal control and external reporting problems.
Because of the importance of communication between the internal auditors and the audit committee, the paper addresses issues such as planning discussions with internal auditors, analysis and conclusions as a result of communication, questionnaire models for the addressed areas and planning the meetings with external auditors
THE USE OF BUDGETS IN FORECASTING THE ACTIVITY OF THE FIRM
No full textThe firm’s activity is recommended to develop in a permanent equilibrium between incomes and expenses. In the actual stage of transition of Romanian economy, the firms can not maintain this equilibrium because the expenses determined by the achievement of production overtake the level of the incomes obtained from the selling of production even when certain branches of activity are subsidized from the public budget. In these conditions, finding the methods that allow the sizing and control of the equilibrium relation between expenses and incomes represents a problem with which the firm’s management confronts. From this point of view the budget can become an instrument of correlation and especially of turning to good account the relation between incomes and expenses. Budgeting becomes a systematic economic practice that assumes the development of a process of formal assignment of financial resources that aim at the achievement of some established objectives for the future periods.budget, budgeting, forecasting, management by using budgets, expenditure budget, budget holders, manufacturing costs.
Correlation of Mesoporous Silica Structural and Morphological Features with Theoretical Three-Parameter Model for Drug Release Kinetics
No full text
Highly Selective Solid Acid Catalyst H1−xTi2(PO4)3−x(SO4)x for Non-Oxidative Dehydrogenation of Methanol and Ethanol
No full textabstract: The conversion of alcohols towards aldehydes in the presence of catalysts by non-oxidative dehydrogenation requires special importance from the perspective of green chemistry. Sodium (Na) super ionic conductor (NASICON)-type hydrogen titanium phosphate sulfate (HTPS; H[subscript 1−x]Ti[subscript 2](PO[subscript 4])[subscript 3−x](SO4)[subscript x], x = 0.5–1) catalysts were synthesized by the sol-gel method, characterized by N[subscript 2] gas sorption, X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), NH[subscript 3] temperature-programmed desorption (NH[subscript 3]-TPD), ultraviolet–visible (UV-VIS) spectroscopy, and their catalytic properties were studied for the non-oxidative dehydrogenation of methanol and ethanol. The ethanol is more reactive than methanol, with the conversion for ethanol exceeding 95% as compared to methanol, where the conversion has a maximum value at 55%. The selectivity to formaldehyde is almost 100% in methanol conversion, while the selectivity to acetaldehyde decreases from 56% to 43% in ethanol conversion, when the reaction temperature is increased from 250 to 400 °C
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