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Lublin, Poland

Hajnos M.,Institute of Agrophysics
Journal of Biomedical Materials Research - Part B Applied Biomaterials | Year: 2016

Natural polymer-based composites become very popular in design of biomaterials for bone tissue regeneration. Their rheological and mechanical properties are typically evaluated in vitro according to standard methods. However, in vivo such composites may behave completely different due to specific body conditions (e.g., inflammation-assisted acidification of tissue liquids). Such surprising phenomenon was observed for hydroxyapatite/β-1, 3-glucan composite during alveolus extraction socket augmentation in people. Implanted composite showed unexpected massive swelling, caused stitches loosening and wound reopening 5 days after implantation. Acidic pH was selected as a potential factor affecting this phenomenon, as all implantations are accompanied by transient local inflammation and acidification. Composite parameters were therefore studied after 5 days of soaking in acidic medium by weight and volume measurement, SEM, XRD, FTIR, microCT, and mercury intrusion techniques. Results showed significant volume increase, pore size remodelling and ceramic phase rearrangement in the composite, accompanied by change of mechanical properties. Simple quantitative correction of amount of implanted composite was sufficient to control in vivo appearance of side effects, confirming that pH-related volume increase of HAp/glucan composite is not a disqualifying factor. This strongly suggests the necessity of very detailed and individually designed tests concerning all new polymer-based composite biomaterials before clinical trials. © 2016 Wiley Periodicals, Inc. Source

Szczes A.,Maria Curie Sklodowska University | Chibowski E.,Maria Curie Sklodowska University | Holysz L.,Maria Curie Sklodowska University | Rafalski P.,Institute of Agrophysics
Chemical Engineering and Processing: Process Intensification | Year: 2011

Water was exposed for different times to weak static magnetic field (MF) generated from a stack of magnets (B=15 mT) or from a single permanent magnet (B=0.27. T) at flow conditions. The water conductivity and the amount of evaporated water were measured as a function of time following the application of MF. It was found that the MF decreases the water conductivity, which is inversely proportional to the flow rate, and increases the amount of evaporated water, even after the water's distillation. The effects are due to the hydrogen bond network strengthening and the perturbation of gas/liquid interface from the air nanobubbles in the water. © 2010 Elsevier B.V. Source

Nwaichi E.O.,Institute of Agrophysics | Nwaichi E.O.,University of Port Harcourt | Wegwu M.O.,University of Port Harcourt | Nwosu U.L.,University of Port Harcourt
Environmental Monitoring and Assessment | Year: 2014

Owing to the importance of clean and fertile agricultural soil for the continued existence of man, this study investigated the concentrations of total petroleum hydrocarbons (TPHs), polycyclic aromatic hydrocarbons (PAHs) and some heavy metals in soils and selected commonly consumed vegetables and tubers from oil-polluted active agricultural farmland in Gokana of Ogoniland, Rivers State, Nigeria. Samples from Umuchichi, Osisioma Local Government Area in Abia State, Nigeria, a non-oil-polluted area constituted the control. In test and control, up to 3,830 ± 19.6 mgkg−1 dw and 6,950 ± 68.3 mgkg−1 dw (exceeding DPR set limits) and 11.3 ± 0.04 mgkg−1 dw and 186 ± 0.02 mgkg−1 dw for TPH and PAHs, respectively, were recorded in test soil and plant samples, respectively. Among the metals studied (Pb, Cd, Cr, Mn, Fe and Zn), Pb and Cr uptake exceeded WHO set limits for crops in test samples. Combined sources of pollution were evident from our studies. Bitterleaf and Waterleaf could be tried as bioindicators owing to expressed contaminants uptake pattern. © 2014, The Author(s). Source

Nwaichi E.O.,University of Port Harcourt | Nwaichi E.O.,Institute of Agrophysics | Frac M.,Institute of Agrophysics | Nwoha P.A.,University of Port Harcourt | Eragbor P.,University of Port Harcourt
International Journal of Phytoremediation | Year: 2015

A field experiment investigating the removal and/or uptake of Polycyclic Aromatic Hydrocarbons (PAHs) and specific metals (As, Cd, Cr) from a crude oil polluted agricultural soil was performed during the 2013 wet season using four plant species: Fimbristylis littoralis, Hevea brasilensis (Rubber plants), Cymbopogom citratus (Lemon grass), and Vigna subterranea (Bambara nuts). Soil functional diversity and soil-enzyme interactions were also investigated. The diagnostic ratios and the correlation analysis identified mixed petrogenic and pyrogenic sources as the main contributors of PAHs at the study site. A total of 16 PAHs were identified, 6 of which were carcinogenic. Up to 42.4 mg kg−1 total PAHs was recorded prior to the experiments. At 90 d, up to 92% total PAH reduction and 96% As removal were achieved using F. littoralis, the best performing species. The organic soil amendment (poultry dung) rendered most of the studied contaminants unavailable for uptake. However, the organic amendment accounted for over 70% of the increased dehydrogenase, phosphatase, and proteolytic enzymes activities in the study. Overall, the combined use of soil amendments and phytoremediation significantly improved the microbial community activity, thus promoting the restoration of the ecosystem. © 2015, Copyright © Taylor & Francis Group, LLC. Source

Salerno M.,Italian Institute of Technology | Zukowska A.,Institute of Agrophysics | Thorat S.,Italian Institute of Technology | Ruffilli R.,Italian Institute of Technology | And 2 more authors.
Journal of Food Engineering | Year: 2014

We studied the nano-scale properties of dry native starch granules of wheat and potato by atomic force microscopy. Whereas at the macroscale the mechanical behavior of starch powders is known, its origin at sub-granule level has still to be understood. We observed fine morphological structures, such as the growth rings and blocklet domains, with minor differences between the two starches. The granules, embedded in resins with known stiffness, were analyzed with lateral-force, force-distance and force-modulation microscopy. Integer granules exhibited a similar friction coefficient to the tip, decreased with respect to the embedding resin, without occurrence of stick-slip. The compressive modulus measured was also similar for both starch types (∼1.4 GPa in indentation and ∼2.0 GPa in dynamic mode), with slightly higher values for potato starch. On sectioned granules, the effect of aging in air likely due to moisture produced in both starches a strong reduction in apparent modulus (∼0.2 GPa). © 2013 Elsevier Ltd. All rights reserved. Source

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