Trees and forests are under increasing threat from pathogens which cause huge economic and ecological damage. The unprecedented global movement of pathogens into new areas creates novel pathosystems, while the changing climate affects the dynamics of endemic pathosystems. Co-evolution within endemic pathosystems affects the genetic composition of hosts and pathogens. Spatial heterogeneity in pathogen pressure leads to genetic variation in disease-related traits among host populations. In contrast, novel hosts or populations are expected to be highly susceptible to exotic pathogens as there has been no evolution of defence responses. Host response to disease can therefore be an indicator of a novel or endemic pathosystem. The long term resilience of forests to pathogens depends on the adaptive capacity of both the host and pathogen species. Establishing the extent of genetic and phenotypic variation within both the host and pathogen is therefore fundamental in understanding past, current and future pathosystem dynamics. The most significant current threat to Scots pine (Pinus sylvestris) is Dothistroma needle blight (DNB) caused by the foliar pathogen Dothistroma septosporum which is assumed to be exotic to Great Britain. This study aimed to increase understanding of the genetic and phenotypic variation in this pathosystem. Results from this study show that there are high levels of variation in the Dothistroma – Pinus pathosystem. Genetic variation, elucidated using neutral genetic markers, mating type specific markers and in vitro analysis of phenotypic variation in D. septosporum collected from Scottish pinewoods, was found to be high: there was high allelic diversity, particularly within plantation forests outside the native pinewood range, and high phenotypic plasticity in response to different temperature treatments. Both mating type idiomorphs were found in one forest which demonstrates their potential for sexual as well as asexual reproduction. There is also tentative evidence from this study that the pathogen is either introduced to Great Britain or that endemic pathogen populations have been augmented with introduced pathogens. Artificial and natural inoculations of native Scots pine provenances with D. septosporum indicate that there is considerable variation in susceptibility to DNB across the native range in Scotland and that variation in this trait is both highly heritable and evolvable. Furthermore, provenance mean susceptibility to DNB is negatively and significantly associated with water-related variables at site of origin, a finding that is potentially indicative of a co-evolutionary history between host and pathogen. Genetic differences among individuals which are ‘resistant’ or ‘susceptible’ to DNB were identified in Pinus radiata for which there has been extensive research in this pathosystem, by comparing the transcriptome sequences of the two phenotypic groups. Nearly half of the genetic differences identified among phenotypes were found in genes with a putative defence function. In conclusion, native Scots pine provenances contain the necessary heritable genetic diversity to evolve a decrease in their susceptibility to D. septosporum through natural selection in response to elevated prevalence of this pathogen. However, implementation of key native pinewood management strategies, including encouraging regeneration in particular, are necessary in order to facilitate the adaptive evolution of native forests to increased levels of DNB. The effectiveness of this response will depend on the rapidity of adaptation of the pathogen. Measures to limit adaptation where possible, including the use of pathogen monitoring and control in nurseries and the limitation of pathogen movement into native pinewoods, should be continued.

Orientador: Carlos Márcio Nóbrega de Jesus / Banca: José Carlos Souza Trindade Filho / Banca: Fabiano André Simões / Resumo: O surgimento do antígeno prostático específico (PSA) revolucionou o diagnóstico, tratamento e seguimento dos pacientes portadores do câncer de próstata (CaP). O limite da normalidade do PSA esta sendo modificado em virtude de um quarto dos CaP serem diagnosticados com PSA menor ou igual a 4,0 ng/ml melhorando o tratamento em virtude do diagnóstico precoce. Estudo retrospectivo com 300 pacientes que foram submetidos ao exame digital da próstata (EDP), PSA e biópsia prostática dirigida pelo ultrassom transretal, com a retirada mínima de 6 fragmentos, em três níveis de PSA, menor ou igual a 4,0 ng/ml, que foram subdivididos conforme os níveis séricos do PSA: menor ou igual a 4,0 ng/ml, entre 4,01 e 10,0 ng/ml e acima de 10,0 ng/ml que compunham respectivamente os grupos 1, 2 e 3.O número e porcentagem de pacientes submetidos a biópsia prostática nos grupos 1, 2, 3 foram 58 (19,3%), 150 (50%) e 92 (30,7%). A taxa de detecção para CaP foi de 32% (96). A taxa de detecção nos G1, G2 e G3 foi 27,6%, 25,3% e 45,6% respectivamente, evidenciando maior positividade no grupo 3 (p=0,003). A idade média nos grupos foi 61±6,5, 64±8,0, 69±9,0 anos com G1,G2<G3 (p < 0,001). O EDP foi normal em 48,7% dos pacientes e em 48,3% (G1), 58% (G2) e (G3) 33,7%, apresentando diferença estatística entre os grupos (p < 0,001). A proporção de fragmentos positivos foi superior no G1 em relação ao G2 (34,5 a 22,7%) mas inferior ao G3 (53,1%). O volume prostático foi menor no G1 (28 cm3) em relação aos demais grupos. Quanto ao escore de Gleason na biópsia, no espécime e no estádio patológico os grupos 1 e 2 foram semelhantes. As principais indicações de biópsia para o G1 foram: EDP alterado: (n= 33) 57%; PSA em elevação isolado (n=19) 32,8%; PSA em elevação e EDP alterado (n= 5) 8,6%; PSA em elevação e relação PSA livre por PSA total menor que 15% (n= 4) ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Prostatic Specific Antigen (PSA) changes the diagnoses, treatment, prognoses and follow-up of prostate cancer (PC). PSA cut-off has been changed due to many patients with PSA lower than 4,0 ng/ml will present a probability of 25% chance to have PC. In these cases, the treatment is favorable because of the early diagnosis. Characterize the main pathological and clinical aspects of patients with PSA lower than 4,0 ng/ml submitted to transrectal prostate biopsy guided by ultrasound. In an observational retrospective study, 300 patients were submitted to digital rectal exam (DRE), PSA serum dosage and transrectal prostate biopsy guided by ultrasound. At least six cores in three PSA levels were performed: lower than 4,0 ng/ml, 4,01 to 10,0 ng/ml, higher than 10,01ng/ml which were groups 1, 2 and 3, respectively. The patients number and percentage submitted to prostatic biopsy in groups 1, 2 and 3 were 58 (19,3%), 150 (50%) e 92 (30,7%). Detection PC rate was 32% (96). Detection PC rate in G1, G2 and G3 was 27,6%, 25,3% and 45,6%, respectively. The age average was 61±6,5, 64±8,0, 69±9,0 years-old with G1,G2<G3 (p < 0,001). The positive cores were higher in G1 than in G2. DRE was normal in 48.7% of all the patients and in 48,3% (G1), 58% (G2) e (G3) 33,7% (p< 0,001). G1 prostate volume was smaller than the others. Prostate biopsy, specimen Gleason Score and the pathological stage were similar between G1 and G2. The main indications for prostate biopsy in G1 were: abnormal DRE (33) 57%; velocity PSA (19) 32,8%; velocity PSA and abnormal DRE (5) 8,6%; velocity PSA and relation of free PSA by total PSA (fPSA/tPSA) less than 15% (4) 6,8%; fPSA/tPSA alone (1) 1,7%; Abnormal DRE and fPSA/tPSA less than 15% (1) 1,7%; Atypical small acinar proliferation (ASAP) (1) 1,7%.The main indication for malignancy positivity were abnormal DRE ... (Complete abstract click electronic access below) / Mestre

Abstract In this study, mineral nutrition and its relation to the vigour of Scots pines growing under the influence of sulphur, copper and nickel stress were investigated. This was done by analysing the nutrient status and needle damage of pines along a pollution transect extending from the proximity of a large S, Cu and Ni emitters on the Kola Peninsula to a background area in Finnish Lapland. Additionally, pine seedlings were exposed to Cu and Ni stress in order to gain more detailed information about the mechanisms behind metal stress. The total sulphur concentrations of the youngest needles in the vicinity of the largest point source were about double compared to those in the reference area (&lt; 800 mg in kg of dry needles vs. > 1900 mg kg-1). In the case of Cu and Ni, this difference was close to 100-fold (from 2-3 mg kg-1 to over 250 mg kg-1). While the elevated sulphur concentrations were not attributable to particle deposition, the particles on needle surfaces raised the total concentrations of Cu and Ni occasionally over 1.5-fold compared to the inside concentrations. The Mn and Zn concentrations showed a decreasing trend, whereas K and P slightly increased towards the Monchegorsk smelters. Enhanced needle senescence and tip necrosis were related to high total foliar levels of Cu, Ni and S and low levels of Zn and Mn. Stomatal chlorosis and other discolourations showed a distinct relation to high SO2 levels in the air and also to high foliar concentrations of Ca, Fe, Si and Cl. Particles deposited on needle surfaces did not cause directly visible injuries in pines. In seedlings, Cu and Ni were enriched in roots: the Ni concentration was up to 16-fold and the Cu concentration 6-fold compared to that added into the soil. While Cu was mostly retained in roots, Ni had much easier access to foliage. The effect of metal stress on other nutrients varied between nutrients, plant parts and metals added. Soil analyses from both the field study and the seedling experiment gave mostly a weak estimation about the plant availability of nutrients. Foliar nutrients remained above the deficiency limits in all studies and were hence not the primary cause for the decrease of pine vigour and the consequent growth retardation and forest decline.

Magister Curationis / The aim of the study was to explore the reasons why health workers reported their occupationally acquired needle stick injury. The secondary reasons for this study was to be able to identify the factors that contributed to the choice to report as well as the feelings health workers experienced during and after the injury. Methodology A qualitative research design with a phenomenological approach was used to gain understanding around why health workers reported the needle stick injury. Data was collected through a semi- structured interview. Population The 89 health workers at a Secondary Hospital in the Cape Town Metropole Health district who reported an occupational injury from 2001 to 2004. Sample Nine health workers were interviewed. Findings From the nine participants only six had needle stick injuries, while the other three had other blood and body fluid occupational exposures. The most common reason for reporting was that the health workers wanted to ensure their own physical well-being. Health workers and their families experienced emotional turmoil after the needle stick injury. / South Africa

abstract: Presented in this thesis are two projects that fall under the umbrella of magnetically actuated electronics and robotics for medical applications. First, magnetically actuated tunable soft electronics are discussed in Chapter 2. Wearable and implantable soft electronics are clinically available and commonplace. However, these devices can be taken a step further to improve the lives of their users by adding remote tunability. The four electric units tested were planar inductors, axial inductors, capacitors and resistors. The devices were made of polydimethylsiloxane (PDMS) for flexibility with copper components for conductivity. The units were tuned using magnets and mobile components comprised of iron filings and ferrofluid. The characteristic properties examined for each unit are as follows: inductance and quality factor (Q-factor) for inductors, capacitance and Q-factor for capacitors, and impedance for resistors. There were two groups of tuning tests: quantity effect and position effect of the mobile component. The position of the mobile component had a larger effect on each unit, with 20-23% change in inductance for inductors (from 3.31 µH for planar and 0.44 µH for axial), 12.7% from 2.854 pF for capacitors and 185.3% from 0.353 kΩ for resistors. Chapter 3 discusses a magnetic needle tracking device with operative assistance from a six degree-of-freedom robotic arm. Traditional needle steering faces many obstacles such as torsional effects, buckling, and small radii of curvature. To improve upon the concept, this project uses permanent magnets in parallel with a tracking system to steer and determine the position and orientation of the needle in real time. The magnet configuration is located at the end effector of the robotic arm. The trajectory of the end effector depends on the needle’s path, and vice versa. The distance the needle travels inside the workspace is tracked by a direct current (DC) motor, to which the needle is tethered. Combining this length with the pose of the end effector, the position and orientation of the needle can be calculated. Simulation of this tracking device has shown the functionality of the system. Testing has been done to confirm that a single magnet pulls the needle through the phantom tissue. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2020

abstract: Needle steering is an extension of manually inserted needles that allows for maneuverability within the body in order to avoid anatomical obstacles and correct for undesired placement errors. Research into needle steering predominantly exploits interaction forces between a beveled tip and the medium, controlling the direction of forces by applying rotations at the base of the needle shaft in order to steer. These systems are either manually or robotically advanced, but have not achieved clinical relevance due to a multitude of limitations including compression effects in the shaft that cause undesired tissue slicing, torsional friction forces and deflection at tissue boundaries that create control difficulties, and a physical design that inherently restricts the workspace. While most improvements into these systems attempt to innovate the needle design or create tissue models to better understand interaction forces, this paper discusses a promising alternative: magnetic needle steering. Chapter 2 discusses an electromagnetic needle steering system that overcomes all aforementioned issues with traditional steering. The electromagnetic system advances the needle entirely magnetically so it does not encounter any compression or torsion effects, it can steer across tissue-interfaces at various angles of attack (90, 45, 22.5°) with root-mean-square error (RMSE) of 1.2 mm, achieve various radii of curvature as low as 10.2 mm with RMSE of 1.4 mm, and steer along complex 3D paths with RMSE as low as 0.4 mm. Although these results do effectively prove the viability of magnetic steering, the electromagnetic system is limited by a weak magnetic field and small 33mm cubic workspace. In order to overcome these limitations, the use of permanent magnets, which can achieve magnetic forces an order of magnitude larger than similarly sized electromagnetics, is investigated. The needle will be steered toward a permanent magnet configuration that is controlled by a 6 degree-of-freedom robotic manipulator. Three magnet configurations were investigated, two novel ideas that attempt to create local maximum points that stabilize the needle relative to the configuration, and one that pulls the needle toward a single magnet. Ultimately, the last design was found to be most viable to demonstrate the effectiveness of magnetic needle steering. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2020

This research study determines the potential to increase substantially the anisotropy of a coke from an aliphatic Waxy Oil produced by Sasol Synfuels at Secunda, South Africa. Experimental modifications included filtration, distillation and thermal treatment, followed by distillation with the aim of producing a carbonised product similar to needle coke. The substantial concentration of an iron oxide catalyst (up to 2%) in Waxy Oil is increased by an order of magnitude upon carbonisation and calcination due to low coke yield and reactivity factors. The catalyst also promotes oxidative polymerisation of the residue, acts as a barrier to mesophase formation and promotes multi-phase graphitisation. Filtration of Waxy Oil using a 0.5 ìm sintered metal filter reduces the ash content to 0.006% and increases the anisotropy of the carbonised product to 54% flow domains compared with 22% for the carbonised product of virgin Waxy Oil. Thermal treatment followed by distillation of Waxy Oil reduces the effect of organic reactivity promoters (mainly multi-alkylated aliphatics/aromatics and oxygenates), while increasing the concentration of thermally stable (C18 to C30) normal alkanes to 85% compared with 38% in the filtered Waxy Oil. Compared with the filtered Waxy Oil, thermally stabilised Waxy Oil reduces the amount of the pre-carbonisation residue (from 98.7 to 43.0%), while “static” carbonisation thereof increases the green coke yield (from 19.8 to 36.3%) and increases the anisotropicity (from 54 to 100% flow domains). The carbonisation mechanism of filtered and thermally treated Waxy Oil involves initial cracking of high molecular weight normal alkanes (C18 to C30), thus concentrating the molecular weight of normal alkanes (C18 to C22). This is followed by a slow cyclisation step involving both self condensation and cyclo addition reactions to form two- to six-ring cyclo-alkanes or hydro-aromatics. The hydro-aromatics are dehydrogenated rapidly to form methyl and di-methyl three- to six-ring substituted aromatics. Further thermal degradation dealkylates these molecules to form stable four- to six-ring “pre-mesogens”. The mesospheres are nucleated from the isotropic matrix and grow to more than 0.050 mm in diameter, with a volume of 2.61 x 10-3 mm3. Subsequent coalescence of the mesospheres produces mesospheres with diameters of over 0.200 mm and volumes of 41.82 x 10-3 mm3. The resultant microstructure of the solid carbon is composed of flow domains more than 400 ìm in length. Although needle cokes have historically been produced from aromatic residues, this research is the first to show that a coke with a similar microstructure can be produced from a totally aliphatic residue. The research thus provides potential for the development of a needle coke from a totally unique Waxy Oil residue with negligible sulphur (< 0.008%) and nitrogen (< 0.09%) contents. This is the first academic study of the chemistry of Waxy Oil. / Thesis (PhD)--University of Pretoria, 2011. / Chemical Engineering / unrestricted

No description available.

The detection or exclusion of metastatic liver involvement is critical in the management and prognosis of patients with malignant disease. Noninvasive imaging modalities such as computed tomography, ultrasound, and technetium colloid liver scan are highly sensitive but nonspecific. Serum alkaline phosphatase is of similar value. A blind liver biopsy by the Menghini technique is often done to confirm the diagnosis, but its yield is low. We prospectively evaluated 74 patients using blind Menghini needle biopsy and concurrent Chiba fine-needle aspiration biopsy (FNAB) techniques. A positive diagnosis of malignancy was made in 30 patients (41%). In only 25 (34%) was the diagnosis made by Menghini biopsy, while Chiba FNAB confirmed the diagnosis in all 30 patients. Thus, concurrent use of both needles increased the diagnostic accuracy by 7%. Seven additional patients, considered to have one or more contraindications for the Menghini biopsy, underwent Chiba FNAB alone; the diagnosis was confirmed in all without complication. We conclude that FNAB alone or in combination with Menghini biopsy is valuable and safe in the diagnosis of metastatic liver disease.

Metastatic carcinomas to the thyroid are quite rare in daily cytology practice. However, when present they may produce a diagnostic dilemma, particularly when they share some morphologic similarities with primary thyroid lesions and when occurring in patients with occult malignant history. Herein, we report a case of metastatic gastric signet ring cell carcinoma to the thyroid. Our patient presented with an isolated right thyroid nodule, which was clinically considered to be a primary thyroid neoplasm. Fine-needle aspiration (FNA) cytology of the nodule revealed a cellular specimen with cohesive fragments and scattered individual neoplastic cells. The neoplastic cells had enlarged nuclei, fine chromatin, and inconspicuous nucleoli. Nuclear crowding, molding, and grooving were prominent. Intranuclear inclusion-like clearance was identified. Some tumor cells also had eccentric nuclei, creating a signet ring cell appearance. The colloid was scant. These cytological features may be seen in cases of papillary thyroid carcinoma or signet ring cell follicular adenoma; however, the presence of the signet ring cells is unusual in primary thyroid lesions and raises the possibility of a metastatic lesion to the thyroid. In our case, the tumor cells were positive for AE1/AE3, mucicarmine, and periodic acid-Schiff, but negative for thyroglobulin and thyroid transcription factor-1. The patient was also found to have a 3.7-cm mass in the distal esophagus/proximal stomach. Biopsy of this mass showed an invasive signet ring cell carcinoma. The purpose of our study is to discuss the cytological features and the differential diagnosis of this unusual thyroid FNA case.