Exhaust emission profiling of fatty acid methyl esters and NOx control studies using selective synthetic and natural additives

The present study was focused on the optimized biodiesel production using Moringa oleifera (M. oleifera) and rice bran oils, characterization, and comparative evaluation of the exhaust emission profile using artificial and natural additives resulting from synthesized biodiesel. Furthermore, various biodiesel blends (B10, B20, B50, and B100) of Moringa oleifera (M. oleifera) and rice bran oils were studied in a four-cylinder, direct injection engine at different engine speeds (1800–3000 rpm). The optimal yields (%) for both the M. oleifera and rice bran oil-based biodiesel were found to be 87 ± 2.0 and 93 ± 2.6%, respectively, using sodium methoxide as the catalyst. The optimized reaction parameters involved in the transesterification of the M. oleifera and rice bran oils were revealed to be catalyst concentration (1.25%), methanol-to-oil molar ratio (9:1), reaction temperature (60 °C), and reaction time (90 min). The fuel properties of the M. oleifera and rice bran oil-based biodiesel were found to be in compliance with ASTM D6751 and EN 14214. The exhaust emission levels of the synthesized biodiesel and its blends with conventional diesel showed a significant reduction in the particulate matter and carbon monoxide levels comparative to the fossil fuel-based diesel combustion, whereas an increasing trend was observed in case of the oxides of nitrogen (NOx) emission. The results of the engine performance test indicated that the brake power in all of the samples had approximately similar values for each load and the enriched blends showed a distinct improvement in brake-specific fuel consumption. The effect of antioxidants on the NOx emission levels resulting from the combustion of the biodiesel and its blends showed that the synthetic additives (butylated hydroxyl anisole (BHA), butylated hydroxyl toluene (BHT), t-butyl hydroquinone (TBHQ), and propyl gallate (PG)) were more effective than the natural methanolic antioxidant extracts (extract of P. pinnata (EPPL), extract of A. lebbeck (EPPL), extract of P. guajava (EPG), and extract of M. azedarcah (EMA) for reduction in the NOx emission level

A dinuclear ruthenium(II) phototherapeutic that targets duplex and quadruplex DNA

With the aim of developing a sensitizer for photodynamic therapy, a previously reported luminescent dinuclear complex that functions as a DNA probe in live cells was modified to produce a new isostructural derivative containing RuII(TAP)2 fragments (TAP = 1,4,5,8- tetraazaphenanthrene). The structure of the new complex has been confirmed by a variety of techniques including single crystal X-ray analysis. Unlike its parent, the new complex displays RuL-based 3MLCT emission in both MeCN and water. Results from electrochemical studies and emission quenching experiments involving guanosine monophosphate are consistent with an excited state located on a TAP moiety. This hypothesis is further supported by detailed DFT calculations, which take into account solvent effects on excited state dynamics. Cell-free steady-state and time-resolved optical studies on the interaction of the new complex with duplex and quadruplex DNA show that the complex binds with high affinity to both structures and indicate that its photoexcited state is also quenched by DNA, a process that is accompanied by the generation of the guanine radical cation sites as photo-oxidization products. Like the parent complex, this new compound is taken up by live cells where it primarily localizes within the nucleus and displays low cytotoxicity in the absence of light. However, in complete contrast to [{RuII(phen)2}2(tpphz)]4+, the new complex is therapeutically activated by light to become highly phototoxic toward malignant human melanoma cell line showing that it is a promising lead for the treatment of this recalcitrant cancer.EPSRC grant EP/M015572/1 Unviersity of Sheffield/EPSRC Doctoral Fellowship Prize EPSRC Capital Equipment Award ERASMUS

Raman spectroscopy detects melanoma and the tissue surrounding melanoma using tissue-engineered melanoma models

Invasion of melanoma cells from the primary tumour involves interaction with adjacent tissues and extracellular matrix. The extent of this interaction is not fully understood. In this study Raman spectroscopy was applied to cryo-sections of established 3D models of melanoma in human skin. Principal component analysis was used to investigate differences between the tumour and normal tissue and between the peri-tumour area and the normal skin. Two human melanoma cells lines A375SM and C8161 were investigated and compared in 3D melanoma models. Changes were found in protein conformations and tryptophan configurations across the entire melanoma samples, in tyrosine orientation and in more fluid lipid packing only in tumour dense areas, and in increased glycogen content in the peri-tumour areas of melanoma. Raman spectroscopy revealed changes around the perimeter of a melanoma tumour as well as detecting differences between the tumour and the normal tissue

DEVELOPMENT OF 3D SKIN MODELS FOR THE DETECTION OF HUMAN MELANOMA USING PHOSPHORESCENCE LIFETIME IMAGING MICROSCOPY

Solid tumours display varied oxygen levels and this characteristic can be exploited to develop new methodologies for detection. MCTS provides a useful model that mimic in vivo tumour microenvironment with varied metabolic gradient (oxygen, pH, glucose and ATP). Emission quenching of phosphorescence compounds by O2 is becoming a wide spread approach for sensing oxygen by optical method within biological model. The approach depends on the correlation of the lifetime of the phosphorescent probe with O2 pressure.The aim is to study the cell penetration and oxygen measurement potential of a novel phosphorescent PtLsCl probe in 2D and 3D biological models using a high resolution 1 and 2-photon emission Phosphorescence Lifetime Imaging Microscopy (PLIM). Quantitative analysis of fluorescence emission intensity and lifetime within cellular compartment showed preferred accumulation of PtLsCl in nucleoli of cells. Immunohistology experiments by Hypoxyprobe™ suggested hypoxia within MCTSs were dependent upon culture condition of MCTS (i.e. size and culture days). Thereafter, emission lifetime detected by 1 or 2-photon PLIM showed marked differences across the 3D MCTS and the variation in lifetime was dependent upon culture condition (size and culture days) of MCTS, suggesting varied oxygen concentration. The distribution of emission lifetime of PtLsCl in whole spheroids ranged from 0 to 12 microseconds with phosphorescence lifetime imaging revealing three distinct lifetime-related oxygen areas. Thereafter, emission lifetime of PtLsCl in the whole melanoma tissue engineered model was analysed. Distribution emission ranged from 0 to 13 microseconds, with phosphorescence lifetime imaging revealing three distinct areas – 1) a normal stromal region of 0 to 4.0 μsec; 2) a spheroid border 4.0 to 6.0 μsec and 3) an inner core of MCTS 6.0 to 13.0 μsec. A marked deviation in lifetime of PtLsCl across the melanoma tissue engineered model clearly demarcated tumour area within normal stroma. It is proposed that the depletion of O2 is known to increase the emission lifetime of the PtLsCl label described herein, and PtLsCl incorporated with 1 or 2 PE-PLIM system demonstrated an excellent potential for high-resolution mapping of oxygen concentration in multi-cellular tissue models. Furthermore, both 1 and 2P-PLIM of a highly sensitive PtLsCl label has shown the potential to detect changes in partial O2 pressure and related response (e.g. necrosis) providing a nove

Fabrication, in vitro and in vivo studies of bilayer composite membrane for periodontal guided tissue regeneration

Development of a guided occlusive biodegradable membrane with controlled morphology in order to restrict the ingrowth of epithelial cells is still a challenge in dental tissue engineering. A bilayer membrane with a non-porous upper layer (polyurethane) and porous lower layer (polycaprolactone and bioactive glass composite) with thermoelastic properties to sustain surgery treatment was developed by lyophilization. Morphology, porosity, and layers attachment were controlled by using the multi-solvent system. In vitro and in vivo biocompatibility, cell attachment, and cell proliferation were analyzed by immunohistochemistry and histology. The cell proliferation rate and cell attachment results showed good biocompatibility of both surfaces, though cell metabolic activity was better on the polycaprolactone-bioactive glass surface. Furthermore, the cells were viable, adhered, and proliferated well on the lower porous bioactive surface, while non-porous polyurethane surface demonstrated low cell attachment, which was deliberately designed and a pre-requisite for guided tissue regeneration/guided bone regeneration membranes. In addition, in vivo studies performed in a rat model for six weeks revealed good compatibility of membranes. Histological analysis (staining with hematoxylin and eosin) indicated no signs of inflammation or accumulation of host immune cells. These results suggested that the fabricated biocompatible bilayer membrane has the potential for use in periodontal tissue regeneration