Ground Penetrating Radar (GPR) methods have been used to evaluate the presence, extent, and spatial variability of hydrophobic soils in Southern California Watersheds. It has been shown that high frequency ground penetrating radar equipment, under certain conditions, has the ability to determine the presence, depth, and persistence of post fire hydrophobic soils. As part of this study an extensive investigation was undertaken to not only evaluate the capability of this approach but also to understand under what conditions the method can be applied successfully and what are the limitations of the approach. The investigation includes use of computer simulations and modeling, laboratory investigations in sand boxes with native soils, and multiple field trials spanning a five year time period. Of particular significance is the finding that using GPR it is possible to: locate the interface between the uppermost burnt soil layer, and soil horizons below; quantify the depth at which the hydrophobic layer forms; and quantify the spatial extent of the layer. As part of this study best practice methods for both field and lab experimentation have also been developed and are presented in the body of the thesis. Based on this study it is concluded that the use of GPR can provide a much more accurate and comprehensive method of evaluating the nature of hydrophobic layers in such environments than the current point specific manual methods. As a result the use of GPR has significantly advanced our capacity to assess the potential for increased erosion and the generation of debris flows in such environments after rainfall events.

Ground penetrating radar (GPR) has been used as a railway substructure investigation tool since the late 1990’s and has seen significant development since then. To use GPR as a more effective tool for substructure investigation, a GPR substructure characterization model was developed. This dissertation provides a detailed description of railway track components, track geometry, soil properties and classification and substructure design. The historical background of GPR is discussed together with GPR principles, basic GPR equations, hardware and accessories as well as GPR data collection, processing and interpretation. Other in situ investigation techniques namely the dynamic cone penetrometer (DCP), light weight deflectometer (LWD) , Pencel pressuremeter, surface wave testing, remote video monitoring (RVM), multi-depth deflectometers (MDD) and continuous track modulus measurement techniques are also discussed. A comparison between the different track investigation techniques was also done, with reference to sample rate, cost, effectiveness and value. Two sites in South Africa were selected for the investigation, one with good substructure conditions used for heavy haul coal export close to Vryheid (KN test section) and the other a general freight line with poor substructure conditions near Rustenburg (NT test section). These two sites were selected to develop a GPR substructure characterization model as they provided conditions ranging from poor to very good. This was supported by the analysis of the in situ soil sampling and testing. The calculation of the track substructure modulus from RVM deflection measurements showed three times higher values for the KN test section compared to the NT test section. The subballast and subgrade thickness, the GPR ballast fouling (GBF) index as well as the GPR moisture condition index was used for the classification ranges used in the model. The subballast and subgrade layer roughness values were calculated and used for the substructure classification. The GBF index and the GPR moisture condition roughness were used for the GPR fouling index classification. The GPR deliverables were divided into four classes (i.e. very good, good, moderate and poor). The evaluation of the characterization model showed that a traditional in situ investigation will cost approximately 3.7 times more than that of a GPR investigation. It would also take two thirds of the time to complete the GPR investigation compared to the traditional in situ investigation. The study showed that GPR can be used to develop a substructure characterization model and that it would be more cost effective and efficient than traditional in situ investigation techniques. GPR surveys provide continuous measurements of the track structure condition and can therefore provide a continuous classification unlike the discreet and fragmented nature of in situ investigations. However, in situ tests can be done at certain intervals within the GPR survey or at point where the GPR classification is not clear. The best solution for railway track characterization can therefore be obtained by using GPR and in situ classification in combination. / Dissertation (MEng)--University of Pretoria, 2012. / Civil Engineering / unrestricted

In the Republic of South Africa, an autopsy is required in all cases of unnatural death, or in cases where the cause of death is unknown in terms of the Inquest Act of 1959. These are performed at the Salt River Medicolegal Laboratory by Forensic Pathologists and Registrars of the Department of Forensic Medicine and Toxicology of the University of Cape Town. The Salt River Medicolegal Laboratory serves the greater Cape Town area with a population of approximately 2,5 million, including the magisterial districts of Cape Town, Wynberg, Mitchell's Plain and Simonstown. Cape Town has one of the world's highest homicide rates and in 1986 the incidence was 56, 91 100000 population per annum. In contrast, Singapore has a homicide rate of only 2, 5/100 000, while the United States has an overall homicide rate of 7,7/ 100 000 population. In order to document the true impact of penetrating chest injuries, and to place mortality data in perspective, a retrospective descriptive study of all cases with fatal penetrating chest injuries admitted to the Salt River Medicolegal Laboratory in Cape Town during 1990 was undertaken. In 1990, a total of 5 758 cases was admitted to the Salt River Medicolegal Laboratory of which 1834 cases (39%) were the result of homicide. Of the homicide cases, 408 (22%) were the result of firearm injuries. A total of 2044 (35, 5%) cases admitted was deemed to have died of natural causes. This study identified a total of 841 cases of fatal penetrating injuries of the chest admitted during 1990, which constituted 22,6% of all non-natural cases admitted.

No description available.

Advanced nondestructive inspection techniques like stress wave timing and resistance microdrilling have been used to successfully inspection timber bridges, but it is most effective on girder style bridges. There is a noted need to develop additional inspection techniques for longitudinal deck/slab timber bridges, which comprise about 20% of the national bridge inventory. One technique that holds potential is ground penetrating radar, a recognized nondestructive testing technique that has been used effectively for many different environmental and transportation applications. It has been utilized successfully to identify buried objects, internal defects and material changes. The objective of this research was to assess the potential for using GPR to identify and assess simulated deterioration in longitudinal timber deck timber bridges. GPR scans were completed in the longitudinal and transverse directions of a screwlaminated timber bridge deck before and after a bituminous layer was added to assess embedded defects that simulated voids, decay, insect damage and horizontal shear splitting. Assessment of the GPR wave energy signal was completed using visualization software that was provided with the commercial GPR unit used for the testing. The radar signal was analyzed in both the longitudinal direction (antenna front to back) and the transverse direction (antenna side to side). Interpretation of the radar signals allowed for the identification of various internal defects present in the deck. Based on the results, GPR has the potential to identify internal defects in timber bridge decks before and after a bituminous layer was added. Large, rectangular void defects (at least 6? by 12? by 5 in. (15.2? by 30.4? by 12.7 cm)) that were hollow, filled with foam, or filled with sawdust/adhesive were most easily identified under all scanning conditions. The addition of a bituminous layer, common to slab bridge construction, damped the signal response and made it more difficult to identify defects. Several smaller defects that were found in the deck without a bituminous layer were not identified in scanning completed after the bituminous layer was added.

The use of geophysical tools to locate clandestine burials involving bodies has seen increasing popularity among forensic personnel. Often, these search methods are important to highlight certain areas where a body may or may not be located prior to utilizing invasive search techniques. Because of the success of these tools within real-life forensic searches, the use of controlled studies that monitor and detect cadavers over certain lengths of time have been increasingly utilized. However, these controlled studies have not monitored various burial scenarios that mimic real-life situations. This study focused on detecting and monitoring six burials containing pig carcasses used as proxies for human bodies and two control burials with a conductivity meter and ground-penetrating radar (GPR) with a 500-MHz and a 250-MHz antenna over a twelve month period. Each burial within this study represented a different forensic scenario that mimicked a real-life situation. Further, forensic use of GPR in both controlled settings as well as real-life searches have mainly focused on the use of a 500-MHz antenna. Therefore, this research also compared the use of a 250-MHz antenna with a 500-MHz antenna. Lastly, a number of GPR imagery options were utilized including reflection profiles and horizontal slices with various GPR software programs to compare the results obtained. Results obtained from the conductivity meter were compared to the results obtained by both antennae of the GPR. Overall, the use of multiple GPR imagery options provided increased resolution of the burial scenarios. Results showed that the conductivity meter was not a beneficial geophysical tool because none of the burial scenarios were detected. On the other hand, the use of GPR showed that the graves with objects added to the pig carcasses provided iv increased resolution compared to the graves containing only pig carcasses. Lastly, the 250-MHz antenna provided better resolution of the burial scenarios than the 500-MHz antenna due to easier discrimination of the forensic targets. Therefore, the use of a 250-MHz antenna would be a viable option to search for clandestine burials containing adult-sized bodies

Cancer is the second leading cause of death in America. In 2018, there were 9.5 million deaths due to cancer according to the International Agency for Research on Cancer (IARC), and this number is expected to grow to 16.3 million by 2040. Among the type of cancers, neuroblastoma and nerve tissue cancers have a 5-year survival rate of 33%, which is very low. One of the main issues linked to such situations is due to the lack of specificity in removing tumor cells. While clinical therapies work to reduce tumor mass as much as possible, they cannot always target all of them, and once some cancer cells are left behind, they regrow and spread. The work of this thesis seeks to enhance the treatment outcome by utilizing all-trans retinoic acid (ATRA), a metabolite of vitamin A, to induce differentiation of nerve tissue cancer cells and eliminate their ability to self-renew (reemerge). Differentiation therapy is currently utilized in select clinical applications but the utilization of ATRA is limited due to its poor solubility in the blood, low bioavailability, short half-life, and in vivo toxicity. In order to alleviate some of these issues, the ATRA molecule was engineered with a novel cell penetrating peptide and tested for its efficacy. Data and results presented herein report the differentiation induced by the CPP-conjugated ATRA may act as a viable method for neuroblastoma treatment. / Bioengineering

Le peptide Tat est un des "cell penetrating peptides" (CPP) les plus utilisés pour l'internalisation cellulaire de diverses molécules cargos. La molécule chimérique (Tat-cargo) induit une réponse biologique plus efficace comparée au cargo seul. Cependant, en marquant le peptide Tat à l'iode 125, il a été déterminé que seulement moins de 1 % de la quantité initiale de peptide est internalisé. Il y a donc une opportunité d'augmenter l'efficacité de cette internalisation. L'étape cruciale du processus d'internalisation est le passage transmembranaire. Cette thèse présente l'évaluation de l'impact d'un groupement hydrophobe intégré en différentes positions au peptide Tat, afin de favoriser son interaction avec la membrane. Un acide aminé modifié chimiquement comportant un groupement cholestéryle a été développé dans ce sens. Cet aminoacide peut être intégré en toute position du peptide Tat. Différentes positions au sein du peptide Tat ont été cholestérylées et l'effet sur le taux d'internalisation a été étudié par cytométrie en flux et par comptage suite au radiomarquage des peptides à l'iode 125.L'ajout de cholestérol en position centrale du peptide Tat induit une efficacité d'internalisation supérieure d'un facteur 30 alors qu'une augmentation moindre est observée suite à l'ajout du groupement hydrophobe en positions latérales, N- ou C-terminale. / The Tat peptide is one of the most used cell penetrating peptides for internalizing various cargo molecules into cells. The chimaeric molecule thus triggers an efficient cellular biological response when compared with the cargo molecule alone. However, following labeling of the Tat peptide with radiolabeled iodine, less than 1% of the external peptide was internalized. Therefore, there is an opportunity to improve the level of CPP internalization. The ultimate step is the crossing through the plasma membrane. This thesis presents an evaluation of the impact of a hydrophobic group incorporated at different positions to Tat peptide, to promote its interaction with the membrane.A chemically modified amino acid comprising a cholesteryl group was developed in this direction. This amino acid can be inserted at any position within the Tat peptide. Different positions within the Tat peptide were cholesterylated and the effect on the internalization rate of Tat CPP was investigated by flow cytometry and by counting following the radiolabeling of peptides with iodine 125.The addition of cholesterol in the central position of the peptide Tat induces internalization efficiency than a factor of 30 while a smaller increase was observed after the addition of hydrophobic group in lateral positions, N-or C-terminus.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / In this paper, the research prototype of a high-performance GPR imaging system is presented. The system is equipped with the capability of synthetic-aperture scan, stepfrequency FMCW illumination, and high-resolution tomographic image reconstruction.

Thesis (PhD) -- Stellenbosch University, 2005. / ENGLISH ABSTRACT: The effective use of borehole radar in geophysical exploration requires accurate knowledge of the dielectric properties of the geological system in which it is employed. The attenuation and propagation velocity of pulses through rock must be known in order to plan and interpret experimental data. Conventional destructive methods for the measurement of hard rock cores require the careful preparation of samples. This firstly necessitates the selection of sampling position and the resulting estimation of rock properties based on sparse measurements, and secondly results in the loss of material and thus data. The ready availability of cylindrical borehole core samples invites the use of a nondestructive means of measuring their properties. A novel design for a flexible guarded capacitor which conforms to a core's cylindrical surface is presented here. T he proposed device has numerous advantages over previous methods. No material is lost to sample preparation and a detailed characterisation of the entire core, including inclusions and transitions between rock types, may be performed. A detailed methodology for the rapid construction of a robust capacitor is given. Guidelines for its operation to achieve repeatable and accurate measurements of the complex dielectric constant of samples of varying homogeneity in the 1- 25 MHz frequency range are presented. The increased amount of data collected from complete core samples is analysed statistically, and amongst other things allows the estimation of the rock's homogeneity. Comparisons of the dielectric properties measured in the laboratory to propagation velocity estimates obtained from crosshole borehole shoots show that a more homogeneous sample is a better predictor of bulk propagating conditions. Detailed studies of the dielectric properties of economically important diamondiferous and platiniferous geological systems show that borehole radar is a feasible tool for the high resolution delineation of ore bodies and other geological targets. / AFRIKAANSE OPSOMMING: Die effektiewe gebruik van boorgatradar in geofisiese eksplorasie benodig akkurate kennis van die dielektriese eienskappe van die geologiese sisteme waarin dit gebruik word. Kennis van die verswakking en voortplantingsnelheid van pulse deur die rots word benodig om eksperimente te beplan en gemete data te interpret eer. Vir konvensionele destruktiewe meetmetodes van harde rotskerne is noukeurige voorbereiding van monsters noodsaaklik. Hierdie proses vereis eerstens 'n keuse van meetposisies en die afskatting van rotseienskappe gebaseer op verspreide metings, en lei tweedens tot die verlies van materiaal en dus data. Die beskikbaarheid van silindriese bom·gat kernmonsters maak dit moontlik om die kerneienskappe op n nie-destruktiewe manier te meet. Die ontwerp van 'n nuwe buigbare afgeskermde kapasitor wat op 'n silindriese kernoppervlak pas, word hier voorgestel. Die toestel het verskeie voordele bo huidige metodes. Geen materiaal word gedurende monstervoorbereiding verloor nie, en 'n volledige beskywing van die eienskappe van die hele kern , met insluitings en oorgange tussen rotstipes, kan verkry word. 'n Gedetaileerde prosedure vir die vinnige konstruksie van 'n robuuste kapasitor word gegee. Die gebruik van die toestel vir herhaalbare en akkurate metings van die komplekse dielektriese konstante van verskillend homogene monsters in die 1- 25 MHz frekwensie bereik word beskryf. Die groter hoeveelheid data wat deur middel van hierdie metode van hele kernmonsters verkry kan word , word statisties geanaliseer, en laat onder andere 'n skatting van die rots se homogeniteit toe. Vergelykings van laboratoriumgemete rotseienskappe met veldskattings van voortplant ingsnelhede wys dat 'n meer homogene monster tot 'n beter afskatting van werklike voortplantingstoestande lei. Studies van die dielektriese eienskappe van ekonomies belangrike diamanthoudende en platinumryk geologiese sisteme wys dat boorgatradar geskik is vir hoe resolusie uitkenning van ertsligame en ander geologiese teikens.