Tiling strategies for optical follow-up of gravitational wave triggers by wide field of view telescopes

Binary neutron stars are among the most promising candidates for joint gravitational-wave and electromagnetic astronomy. The goal of this work is to investigate the strategy of using gravitational wave sky-localizations for binary neutron star systems, to search for electromagnetic counterparts using wide field of view optical telescopes. We examine various strategies of scanning the gravitational wave sky-localizations on the mock 2015-16 gravitational-wave events. We propose an optimal tiling-strategy that would ensure the most economical coverage of the gravitational wave sky-localization, while keeping in mind the realistic constrains of transient optical astronomy. Our analysis reveals that the proposed tiling strategy improves the sky-localization coverage over naive contour-covering method. The improvement is more significant for observations conducted using larger field of view telescopes, or for observations conducted over smaller confidence interval of gravitational wave sky-localization probability distribution. Next, we investigate the performance of the tiling strategy for telescope arrays and compare their performance against monolithic giant field of view telescopes. We observed that distributing the field of view of the telescopes into arrays of multiple telescopes significantly improves the coverage efficiency by as much as 50% over a single large FOV telescope in 2016 localizations while scanning around 100 sq. degrees. Finally, we studied the ability of optical counterpart detection by various types of telescopes. In Our analysis for a range of wide field-of-view telescopes we found improvement in detection upon sacrificing coverage of localization in order to achieve greater observation depth for very large field-of-view - small aperture telescopes, especially if the intrinsic brightness of the optical counterparts are weak.Comment: Accepted for publication in A&A. 10 pages, 10 figure

Localization in Unstructured Environments: Towards Autonomous Robots in Forests with Delaunay Triangulation

Autonomous harvesting and transportation is a long-term goal of the forest industry. One of the main challenges is the accurate localization of both vehicles and trees in a forest. Forests are unstructured environments where it is difficult to find a group of significant landmarks for current fast feature-based place recognition algorithms. This paper proposes a novel approach where local observations are matched to a general tree map using the Delaunay triangularization as the representation format. Instead of point cloud based matching methods, we utilize a topology-based method. First, tree trunk positions are registered at a prior run done by a forest harvester. Second, the resulting map is Delaunay triangularized. Third, a local submap of the autonomous robot is registered, triangularized and matched using triangular similarity maximization to estimate the position of the robot. We test our method on a dataset accumulated from a forestry site at Lieksa, Finland. A total length of 2100\,m of harvester path was recorded by an industrial harvester with a 3D laser scanner and a geolocation unit fixed to the frame. Our experiments show a 12\,cm s.t.d. in the location accuracy and with real-time data processing for speeds not exceeding 0.5\,m/s. The accuracy and speed limit is realistic during forest operations

Immuno Magnetic Thermosensitive Liposomes For Cancer Therapy

The present work describes the encapsulation of the drug doxorubicin (DOX) in immuno paramagnetic thermosensitive liposomes. DOX is the most common chemotherapeutic agent for the treatment of a variety of carcinomas. However, the pure drug has high cytotoxicity and therefore requires a targeted and biocompatible delivery system. The introduction includes concepts, modalities, and functionalities of the project. First, a detailed description of the cell type (triple-negative breast cancer) is given. Furthermore, the importance of liposomal doxorubicin is explained and the current state of research is shown. The importance of modification to achieve thermosensitive properties and the procedure for co-encapsulation with Gd chelate to achieve paramagnetic properties is also discussed. In addition, the first part describes the surface modification with ADAM8 antibodies, which leads to improved targeting. The second part of the thesis covers the different materials and methods used in this paper. The production of the liposomes LipTS, LipTS-GD, LipTS-GD-CY, LipTS-GD-CY-MAB and the loading of DOX using an ammonium sulfate gradient method were described in detail. The results part deals with the physicochemical characterization using dynamic light scattering and laser Doppler velocimetry, which confirmed a uniform monodisperse distribution of the liposomes. These properties facilitate the approach of liposomes to target cancer cells. The influence of lipid composition of liposomes, co-encapsulation with Gd chelate and surface modification of liposomes was evaluated and described accordingly. The size and structure of the individual liposomal formulations were determined by atomic force microscopy and transmission electron microscopy. Morphological examination of the liposomes confirmed agreement with the sizes obtained by dynamic light scattering. Temperature-dependent AFM images showed an intact liposome structure at 37 °C, whereas heating by UHF-MRI led to a lipid film indicating the destruction of the lipid bilayer. Furthermore, TEM images showed the morphological properties of the liposomes and gave a more precise indication of how Gd-chelate accumulates within the liposomes. Liposomes with Gd-chelate showed well-separated vesicles, suggesting that Gd- chelate is deposited in the lipid bilayer of the liposomes. Gd was encapsulated in the hydrophilic core whereas chelate was extended into the lipid bilayer. By differential scanning calorimetry and drug release, the heat-sensitive functionality of the liposomes could be determined. Liposomes showed a beginning of phase transition temperature at about 38 °C, which can be achieved by UHF-MRI exposure. The maximum phase transition temperature in the case of LipTS-GD and LipTS-GD-CY-MAB was 42 °C and 40 °C, respectively. A proof of concept study for the thermosensitive properties of liposomes and a time-dependent DOX release profile in hyperthermia was performed. Gd-chelate is encapsulated in both LipTS-GD and LipTS-GD-CY-MAB and led to paramagnetic properties of the liposomes. This facilitates imaging mediated DOX delivery and diagnosis of the solid tumor and metastatic cells. The change in relaxation rate R1 of liposomes was quantified before and after heating above Tm (T> Tm). The relaxivity of the liposomes was obtained from the adapted slope of the relaxation rate against the Gd concentration. Remarkably, the relaxation rate and relaxivity increased after heating the liposomes above Tm (T> Tm), suggesting that the liposomes opened, released Gd chelate, and the exchange of water molecules became faster and more practicable. Toxicity studies describe the different mechanisms for induced DOX toxicity. The increased cytotoxic effect at elevated temperatures showed that the induced toxicity is thermally dependent, i.e. DOX was released from the liposomes. The high viability of the cells at 37 °C indicates that the liposomes were intact at normal physiological temperatures. Under UHF-MRI treatment, cell toxicity due to elevated temperature was observed. The cellular uptake of liposomes under UHF-MRI was followed by a confocal laser scanning microscope. An increase in fluorescence intensity was observed after UHF-MRI exposure. The study of the uptake pathway showed that the majority of liposomes were mainly uptake by clathrin-mediated endocytosis. In addition, the liposomes were modified with anti-ADAM8 antibodies (MAB 1031) to allow targeted delivery. The cellular binding capabilities of surface-modified and non-modified liposomes were tested on cells that had ADAM8 overexpression and on ADAM8 knockdown cells. Surface-modified liposomes showed a significant increase in binding ability, indicating significant targeting against cells that overexpress ADAM8 on their surface. In addition, cells with knockdown ADAM8 could not bind a significant amount of modified liposomes. The biocompatibility of liposomes was assessed using a hemolysis test, which showed neglected hemolytic potential and an activated thromboplastin time (aPTT), where liposomes showed minimal interference with blood clotting. Hemocompatibility studies may help to understand the correlation between in vitro and in vivo. The chorioallantois model was used in ovo to evaluate systematic biocompatibility in an alternative animal model. In the toxicity test, liposomes were injected intravenously into the chicken embryo. The liposomes showed a neglectable harmful effect on embryo survival. While free DOX has a detrimental effect on the survival of chicken embryos, this confirms the safety profile of liposomes compared to free DOX. LipTS-GD-CY-MAB were injected into the vascular system of the chicken embryo on egg development day 11 and scanned under UHF-MRI to evaluate the magnetic properties of the liposomes in a biological system with T2-weighted images (3D). The liposomal formulation had distinct magnetic properties under UHF MRI and the chick survived the scan. In summary, immunomagnetic heat-sensitive liposomes are a novel drug for the treatment of TNBC. It is used both for the diagnosis and therapy of solid and metastasizing tumors without side effects on the neighboring tissue. Furthermore, a tumor in the CAM model will be established. Thereafter, the selective targeting of the liposomes will be visualized and quantitated using fluorescence and UHF-MRI. Liposomes are yet to be tested on mice as a xenograft triple-negative breast cancer model, in which further investigation on the effect of DOX-LipTS-GD-CY-MAB is evaluated. On one hand, the liposomes will be evaluated regarding their targetability and their selective binding. On the other hand, the triggered release of DOX from the liposomes after UHF-MRI exposure will be quantitated, as well as evaluate the DOX-Liposomes therapeutic effect on the tumor

3D Reconstruction & Assessment Framework based on affordable 2D Lidar

Lidar is extensively used in the industry and mass-market. Due to its measurement accuracy and insensitivity to illumination compared to cameras, It is applied onto a broad range of applications, like geodetic engineering, self driving cars or virtual reality. But the 3D Lidar with multi-beam is very expensive, and the massive measurements data can not be fully leveraged on some constrained platforms. The purpose of this paper is to explore the possibility of using cheap 2D Lidar off-the-shelf, to preform complex 3D Reconstruction, moreover, the generated 3D map quality is evaluated by our proposed metrics at the end. The 3D map is constructed in two ways, one way in which the scan is performed at known positions with an external rotary axis at another plane. The other way, in which the 2D Lidar for mapping and another 2D Lidar for localization are placed on a trolley, the trolley is pushed on the ground arbitrarily. The generated maps by different approaches are converted to octomaps uniformly before the evaluation. The similarity and difference between two maps will be evaluated by the proposed metrics thoroughly. The whole mapping system is composed of several modular components. A 3D bracket was made for assembling of the Lidar with a long range, the driver and the motor together. A cover platform made for the IMU and 2D Lidar with a shorter range but high accuracy. The software is stacked up in different ROS packages.Comment: 7 pages, 9 Postscript figures. Accepted by 2018 IEEE International Conference on Advanced Intelligent Mechatronic