48 research outputs found

    Nanocomposites of Reduced Graphene Oxide for Energy Storage Applications

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    A well-crystallized and nano-sized Metal oxide/reduced graphene oxide composite material for lithium ion batteries has been successfully synthesized. The nano-sized metal oxide particles were evenly dispersed on the reduced graphene oxide template without any agglomeration, which allows the inherent high active surface area of individual metal oxide nano-particles in the composite. These unique structural and morphological properties of metal oxide on the highly conductive reduced graphene oxide sheets in the composite enable achieving the high specific capacity, and excellent high rate capability and stable cycling performance. an analysis of the cyclic voltammogram data revealed that a large surface charge storage contribution of the metal oxide/reduced graphene oxide nanocomposite plays an important role in achieving faster charge/discharge. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3526

    Gelatin-apatite bone mimetic co-precipitates incorporated within biopolymer matrix to improve mechanical and biological properties useful for hard tissue repair

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    Synthetic biopolymers are commonly used for the repair and regeneration of damaged tissues. Specifically targeting bone, the composite approach of utilizing inorganic components is considered promising in terms of improving mechanical and biological properties. We developed gelatin-apatite co-precipitates which mimic the native bone matrix composition within poly(lactide-co-caprolactone) (PLCL). Ionic reaction of calcium and phosphate with gelatin molecules enabled the co-precipitate formation of gelatin-apatite nanocrystals at varying ratios. The gelatin-apatite precipitates formed were carbonated apatite in nature, and were homogeneously distributed within the gelatin matrix. The incorporation of gelatin-apatite significantly improved the mechanical properties, including tensile strength, elastic modulus and elongation at break, and the improvement was more pronounced as the apatite content increased. Of note, the tensile strength increased to as high as 45 MPa (a four-fold increase vs. PLCL), the elastic modulus was increased up to 1500 MPa (a five-fold increase vs. PLCL), and the elongation rate was ∼240% (twice vs. PLCL). These results support the strengthening role of the gelatin-apatite precipitates within PLCL. The gelatin-apatite addition considerably enhanced the water affinity and the acellular mineral-forming ability in vitro in simulated body fluid; moreover, it stimulated cell proliferation and osteogenic differentiation. Taken together, the GAp-PLCL nanocomposite composition is considered to have excellent mechanical and biological properties, which hold great potential for use as bone regenerative matrices

    Breath biomarkers in idiopathic pulmonary fibrosis:A systematic review 11 Medical and Health Sciences

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    Background: Exhaled biomarkers may be related to disease processes in idiopathic pulmonary fibrosis (IPF) however their clinical role remains unclear. We performed a systematic review to investigate whether breath biomarkers discriminate between patients with IPF and healthy controls. We also assessed correlation with lung function, ability to distinguish diagnostic subgroups and change in response to treatment. Methods: MEDLINE, EMBASE and Web of Science databases were searched. Study selection was limited to adults with a diagnosis of IPF as per international guidelines. Results: Of 1014 studies screened, fourteen fulfilled selection criteria and included 257 IPF patients. Twenty individual biomarkers discriminated between IPF and controls and four showed correlation with lung function. Meta-analysis of three studies indicated mean (± SD) alveolar nitric oxide (CalvNO) levels were significantly higher in IPF (8.5 ± 5.5 ppb) than controls (4.4 ± 2.2 ppb). Markers of oxidative stress in exhaled breath condensate, such as hydrogen peroxide and 8-isoprostane, were also discriminatory. Two breathomic studies have isolated discriminative compounds using mass spectrometry. There was a lack of studies assessing relevant treatment and none assessed differences in diagnostic subgroups. Conclusions: Evidence suggests CalvNO is higher in IPF, although studies were limited by small sample size. Further breathomic work may identify biomarkers with diagnostic and prognostic potential

    Characterisation of Reference Materials for In situ Rb-Sr Dating by LA-ICP-MS/MS

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    International audienceWe present here Rb and Sr mass fractions and 87 Sr/ 86 Sr compositions for four reference materials (RM) obtained from the Service d'Analyse des Roches et des Minéraux (SARM) in Nancy, France: Mica-Mg, Mica-Fe, GL-O and FK-N. These four RMs have different chemical compositions spanning the range of those of most K-bearing feldspars and micas, making them potential calibration materials for in situ Rb-Sr dating of natural minerals by LA-ICP-MS/MS. Selected grains and flakes from the four RMs present variable degrees of heterogeneity observable by SEM-EDS and EPMA imaging and chemical mapping. This heterogeneity is mainly related to inclusions of minerals within flakes and grains and to chemical substitutions linked to crystallographic control and alteration processes. The Mica-Mg RM is the least affected. The powders available at the SARM were analysed by ID-TIMS (87 Sr/ 86 Sr and Sr mass fractions) and ID-MC-ICP-MS (Rb) after digestion and separation. The mean 87 Rb/ 86 Sr ratios are 155.6 ± 4.7% (2s, as for other RMs) for Mica-Mg, 1815 ± 14% for Mica-Fe, 36.2 ± 11% for GL-O and 69.9 ± 5.9% for FK-N. The mean 87 Sr/ 86 Sr ratios are 1.8622 ± 0.36% (2s, as for other RMs) for Mica-Mg, 7.99 ± 13% for Mica-Fe, 0.75305 ± 0.12% for GL-O, and 1.2114 ± 0.17% for FK-N. The four RMs each show dispersion in 87 Sr/ 86 Sr and Rb and Sr mass fractions, to degrees that differ between RMs and that reflect the heterogeneity of their original crystals. The most heterogeneous RMs are GL-O and Mica-Fe. The calculated mean Rb-Sr isotopic ages are 521 ± 24 Ma for Mica-Mg, 287 ± 55 Ma for Mica-Fe, 89.2 ± 9.9 Ma for GL-O and 512 ± 30 Ma for FK-N. The proposed age for Mica-Fe may be unreliable due to the elevated dispersion of individual analysis linked to the highly radiogenic composition of the biotite and to the presence of numerous mineral inclusions. We recommend use of these proposed working values of 87 Sr/ 86 Sr and 87 Rb/ 86 Sr ratios and associated uncertainties when using the four RMs for in situ Rb-Sr dating by LA-ICP-MS/MS. The availability of these four well-characterised RM will allow progress in the development and application of the Rb-Sr dating approach by LA-ICP-MS/MS
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