Retrofitting a high-speed marine engine to dual-fuel methanol-diesel operation : a comparison of multiple and single point methanol port injection

As a result of climate change and increasingly stringent emission legislation the shipping industry has started with a transition to sustainable propulsion. Methanol is a viable fuel to reach this goal: it is a great engine fuel (high octane number, high heat of evaporation, and absence of carbon to carbon bonds) and a simple molecule that can be produced in a renewable way. The dual-fuel methanol-diesel technology with methanol injection in the intake has proven to be a promising retrofit solution for vessels. In this concept methanol injectors can be at multiple locations: single point injection (SPI) in the intake duct (assumed to be easier to install) or multiple point injection (MPI) at the intake ports of the cylinders (assumed to give additional in-cylinder cooling to suppress knock). This paper compares MPI and SPI with a focus on maximum methanol energy fraction (MEF), brake thermal efficiency (BTE) and NOx emissions; and compares both injection modes with diesel-only operation. The highest MEF was measured in SPI: 84%. BTE was significantly higher in SPI for high MEFs due to a better combustion phasing resulting from higher intake temperatures. Higher intake temperatures in SPI resulted in higher NOx emissions. Independent of the injection mode, NOx mainly decreased compared to diesel-only operation. It is concluded that SPI is preferred from a cost point of view (maximizing BTE and minimizing retrofit cost) and that MPI is preferred from a sustainability point of view (maximizing MEF and minimizing NOx emissions)

PSR J1024-0719:A Millisecond Pulsar in an Unusual Long-Period Orbit

PSR J1024-0719 is a millisecond pulsar that was long thought to be isolated. However, puzzling results concerning its velocity, distance, and low rotational period derivative have led to a reexamination of its properties. We present updated radio timing observations along with new and archival optical data which show that PSR J1024-0719 is most likely in a long-period (2-20 kyr) binary system with a low-mass (approximate to 0.4 M-circle dot), low-metallicity (Z approximate to -0.9 dex) main-sequence star. Such a system can explain most of the anomalous properties of this pulsar. We suggest that this system formed through a dynamical exchange in a globular cluster that ejected it into a halo orbit, which is consistent with the low observed metallicity for the stellar companion. Further astrometric and radio timing observations such as measurement of the third period derivative could strongly constrain the range of orbital parameters

Identification and characterisation of the haematopoietic stem/progenitor cells at risk for leukaemia development following radiation exposure

A variety of epidemiological studies have provided support for an increased leukaemia incidence following exposure to both high and low dose radiation. There is a close histopathological similarity between human and murine acute myeloid leukaemia with mouse models of the disease being most often used. We report here, for the first time, that allogeneic haematopoietic stem cells can compete for niches in the nonmyeloablated NSG bone marrow compartment and that the nonmyeloablated NSG bone marrow microenvironment is capable of supporting allogeneic long-term HSC engraftment and differentiation. Using this NSG transplantation model, we then provided evidence of a reduced contribution of low dose irradiated HSCs towards longterm haematopoiesis. We further report on the generation and characterisation of a novel Chr2MDRmCh mouse model where a construct positioned in the minimal deleted region following radiation exposure carries the fluorescent protein mCherry, which is expressed under control of the ubiquitous Rosa26 promoter. Crossing these mice with Sfpi1GFP mice allowed the early detection of an expanding haematopoietic clone which had lost mCherry fluorescence following radiation exposure (and so also the chromosome 2 homologue carrying the fluorescent construct and the Sfpi1 gene). Finally, we report on a gender-dependent leukaemic progression and characterisation where 3 Gy irradiated male mice only present with acute myeloid leukemia and irradiated female mice mainly develop leukaemia with a lymphoid phenotype. In conclusion, the work in this thesis postulates data obtained from two novel mouse models and which could help to further identify key molecular mechanisms involved in leukaemia initiation and development.</p

Identification and characterisation of the haematopoietic stem/progenitor cells at risk for leukaemia development following radiation exposure

A variety of epidemiological studies have provided support for an increased leukaemia incidence following exposure to both high and low dose radiation. There is a close histopathological similarity between human and murine acute myeloid leukaemia with mouse models of the disease being most often used. We report here, for the first time, that allogeneic haematopoietic stem cells can compete for niches in the nonmyeloablated NSG bone marrow compartment and that the nonmyeloablated NSG bone marrow microenvironment is capable of supporting allogeneic long-term HSC engraftment and differentiation. Using this NSG transplantation model, we then provided evidence of a reduced contribution of low dose irradiated HSCs towards longterm haematopoiesis. We further report on the generation and characterisation of a novel Chr2MDRmCh mouse model where a construct positioned in the minimal deleted region following radiation exposure carries the fluorescent protein mCherry, which is expressed under control of the ubiquitous Rosa26 promoter. Crossing these mice with Sfpi1GFP mice allowed the early detection of an expanding haematopoietic clone which had lost mCherry fluorescence following radiation exposure (and so also the chromosome 2 homologue carrying the fluorescent construct and the Sfpi1 gene). Finally, we report on a gender-dependent leukaemic progression and characterisation where 3 Gy irradiated male mice only present with acute myeloid leukemia and irradiated female mice mainly develop leukaemia with a lymphoid phenotype. In conclusion, the work in this thesis postulates data obtained from two novel mouse models and which could help to further identify key molecular mechanisms involved in leukaemia initiation and development.</p

Targeting PDK and PARP to improve radiation response in preclinical models of non-small cell lung cancer

Approximately 50 % of all NSCLC patients receive radiation therapy during the course of their disease, and the quest to enhance the radiation response of these patients is still ongoing. Here, we investigate the potential to increase the radiation response of NSCLC by targeting the PI3K signalling pathway with PDK1 inhibitors and/or targeting DNA repair with the PARP inhibitor olaparib. The in vitro radiosensitising effect of the PARP inhibitor olaparib and the PDK1 inhibitors BX912 and GSK2334470 was determined using clonogenic survival assays. The combination of PDK1 inhibitors with radiation did not increase the radiosensitivity of NSCLC cell lines, irrespective of the TP53 status. However, a significant radiosensitisation was observed by addition of olaparib to radiation treatment (SER50 1.6 to 2.2). Immunofluorescent quantification of γH2AX foci formation indicated that the radiosensitisation effect of olaparib could be explained by inhibition of DNA repair. Subsequently, we demonstrated that olaparib enhances the radiosensitivity of a poorly vascularised NSCLC xenograft model by decreasing DNA repair and increasing apoptosis. In contrast, a well vascularised NSCLC model was not sensitised by addition of olaparib to radiation treatment. The effect of olaparib on in vivo vascular perfusion was assessed using dynamic contrast enhanced-magnetic resonance imaging. No significant differences were observed between olaparib and vehicle treated xenografts, suggesting that the radiosensitising effect can be mainly attributed to inhibition of DNA repair. We demonstrated that olaparib is a potent radiosensitiser in a poorly vascularised lung cancer model but further in vivo experiments are warranted to identify the subset of patients that would benefit from olaparib addition to radiation therapy.</p

Targeting PDK and PARP to improve radiation response in preclinical models of non-small cell lung cancer

Approximately 50 % of all NSCLC patients receive radiation therapy during the course of their disease, and the quest to enhance the radiation response of these patients is still ongoing. Here, we investigate the potential to increase the radiation response of NSCLC by targeting the PI3K signalling pathway with PDK1 inhibitors and/or targeting DNA repair with the PARP inhibitor olaparib. The in vitro radiosensitising effect of the PARP inhibitor olaparib and the PDK1 inhibitors BX912 and GSK2334470 was determined using clonogenic survival assays. The combination of PDK1 inhibitors with radiation did not increase the radiosensitivity of NSCLC cell lines, irrespective of the TP53 status. However, a significant radiosensitisation was observed by addition of olaparib to radiation treatment (SER50 1.6 to 2.2). Immunofluorescent quantification of γH2AX foci formation indicated that the radiosensitisation effect of olaparib could be explained by inhibition of DNA repair. Subsequently, we demonstrated that olaparib enhances the radiosensitivity of a poorly vascularised NSCLC xenograft model by decreasing DNA repair and increasing apoptosis. In contrast, a well vascularised NSCLC model was not sensitised by addition of olaparib to radiation treatment. The effect of olaparib on in vivo vascular perfusion was assessed using dynamic contrast enhanced-magnetic resonance imaging. No significant differences were observed between olaparib and vehicle treated xenografts, suggesting that the radiosensitising effect can be mainly attributed to inhibition of DNA repair. We demonstrated that olaparib is a potent radiosensitiser in a poorly vascularised lung cancer model but further in vivo experiments are warranted to identify the subset of patients that would benefit from olaparib addition to radiation therapy.This thesis is not currently available in ORA

Resolving enantiomers using the optical angular momentum of twisted light

Circular dichroism and optical rotation are crucial for the characterization of chiral molecules and are of importance to the study of pharmaceutical drugs, proteins, DNA, and many others. These techniques are based on the different interactions of enantiomers with circularly polarized components of plane wave light that carries spin angular momentum (SAM). For light carrying orbital angular momentum (OAM), for example, twisted or helical light, the consensus is that it cannot engage with the chirality of a molecular system as previous studies failed to demonstrate an interaction between optical OAM and chiral molecules. Using unique nanoparticle aggregates, we prove that optical OAM can engage with materials' chirality and discriminate between enantiomers. Further, theoretical results show that compared to circular dichroism, mainly based on magnetic dipole contributions, the OAM analog helical dichroism (HD) is critically dependent on fundamentally different chiral electric quadrupole contributions. Our work opens new venues to study chirality and can find application in sensing and chiral spectroscopy.status: publishe

Ultrasonic Spray Coating as a Fast Alternative Technique for the Deposition of Hybrid Magnetic-Plasmonic Nanocomposites

© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Advanced applications in optics, for example, Faraday isolators, demand for complex magneto-plasmonic nanostructures which exhibit large Faraday rotation. These structures is fabricated by a Layer-by-Layer approach, albeit this being a slow technique. Here, the ultrasonic spray coating as a promising alternative method toward the formation of hybrid magneto-plasmonic structures is pioneered by the authors. Ultrasonic spray coating is a stable, fast, and tunable mass production method applied in this work to deposit gold and iron oxide nanoparticles. Altering multiple deposition parameters give the spray coating technique a large amount of control over the coverage. Optical and magneto-optical properties, layer formation and surface coverage of single and hybrid layers with increasing thickness and number of layers are studied and compared to samples synthesized by Layer-by-Layer deposition. Ultrasonic spray coating paves the way to the widespread application of innovative and versatile hybrid magnetic-plasmonic nanocomposites.status: publishe