Thesis (M. Sc.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 57-60).

Background: Paediatric poisoning is a common presentation to emergency departments worldwide. There is a paucity of data on the role of liquid chromatography-tandem mass spectrometry (LC-MS/MS), in the management of paediatric poisoning in low-and middle-income countries (LMICs). In high-income countries, most studies are retrospective, and few include children. Objective: The study describes the prevalence of liquid chromatography-tandem mass spectrometry confirmed paediatric poisoning at Red Cross War Memorial Children's Hospital, Cape Town, South Africa. Methods Children admitted with suspected poisoning between 1 January 2017 and 31 December 2017, were recruited. All patients had a urine and/or blood sample sent for LC-MS/MS toxicology. Data collected included demographic data, clinical features, investigations, management, outcome and social interventions. Results 152 children, with median age of 39 (IQR 25 -61) months were enrolled of which 128 (84%) were poisoning cases. Of the 128 poisoning cases, 88 (69%) presented with a history of ingesting a known substance, 16(12%) an unknown substance and 24(19%) were cases of occult poisoning. LC-MS/MS was able to identify a substance in 92% of the cases of occult poisoning. In those who had presented with a seemingly known substance, LC-MS/MS found a different substance in 15 cases. LC-MS/MS was also able to detect multiple drugs in 40 patients. Of the poisoning cases, six (5%) cases were attempted homicide cases and 5 (4%) cases were attempted suicide cases. No children died. Individualized social interventions were instituted in poisoning cases. Emergency placement safety reasons was required in 6 children. Conclusion: When the limitations are known, LC-MS/MS is useful in identifying cases of occult poisoning; identifying patients who have ingested multiple substances and/or an unknown substance and when targeted towards child protection. As LC-MS/MS is an expensive test, it should be used judiciously in LMICs.

Poisonous plants are one of the most important causes of economic losses in the livestock industry throughout the world, especially in those areas where rangeland and pasture grazing are practiced. In the livestock industry in South Africa, total annual costs of plant and fungal poisoning (mycotoxicosis) are conservatively estimated to be R104 506 077, 8% of which is due to D. cymosum poisoning. There is no antidote for D. cymosum poisoning of livestock and wide scale eradication by conventional control methods are labour intensive, expensive and often impractical. In South Africa, the communal or emerging farming sectors are the most affected. This is mainly due to the high costs associated with control measures such as fencing, supplementary feeding and veterinary expenses, and / or lack of grazing management with livestock numbers exceeding the biological carrying capacity of the rangeland due to lack of grazing lands. Proper rangeland management is the surest and most economical means of reducing plant poisoning of livestock. Focused research on the ecology of these poisonous plants in rangeland communities to improve rangeland management would assist in the development of these strategies. This study investigated D. cymosum infested savanna communities, focusing on understanding how negative (inter- and intraspecific competition) interactions influence community structure, dynamics and productivity and how plants in D. cymosum communities avoid these negative interactions by investigating their seasonal phenological patterns. Dichapetalum cymosum coexists with trees, such as Burkea africana, Ochna pulchra and Terminalia serecia, as well as shrubs species, such as Pygmaeothamnus zeyheri and Perinari capensis, in well drained, nutrient poor soils. Some plant ecologists contend that in an environment where water is limited, competition is inevitable amongst plants occupying the same above-ground stratum and the same soil horizon. Others contend that plants avoid competition with each other by sharing resources spatially and temporarily. Field experiments were conducted to investigate how the above species interact and coexist with each other in two South African savanna communities. Fourteen (100 m x 100 m) D. cymosum infested sites were identified in each community. Disperal analysis using nearest neighbour distance was used to investigate competition among species, and above ground flowering phenology along niche axes to determine temporal and spatial sharing of resources. The dispersal analysis revealed aggregated populations among species when intraspecific and combined (all individuals independent of species) analyses were conducted. However, in all instances, aggregation among species was not significant. No interspecific competition was observed among species when correlation analysis was performed between nearest neighbour distance and combined canopy cover of the nearest neighbour pair. Intraspecific competition was, however, observed for tree species T. sericea (n = 128; r = 0.3952; P < 0.0001) and B. africana (n = 166; r = 0.49926; P <0.0001) and a shrub species, D. cymosum (n = 391; r = 0.39788; P <0.0001). Segregation was found between O. pulchra and both B. africana (S = 0.999, χ² = 102.7588, P <0.0001) and T. sericea (S = 0.999, χ² = 57.8571, P <0.0001). Shrub species were also segregated, all with interspecific nearest neighbour pairs occurring less often than expected. The vegetative phenology of all experimental plant species followed the rainfall gradient. Differences in reproductive phenologies were observed between O. pulchra and both B. africana and T. sericea. Dichapetalum cymosum also differed from P. capensis and P. zeyheri in their reproductive phenologies. The differences in the reproductive strategies of at least one of the species in each growth form account for the observed spatial distribution amongst species in these communities. The observed growth patterns shown by the vegetative phenologies, however, suggest that lengthy retention of nutrients is a strategy to avoid competition for nutrient uptake with other species in these communities. Segregation between species and positive correlation iii between nearest neighbour distance and combined canopy cover of the nearest neighbour pairs suggest that intraspecific competition and interspecific facilitation determine D. cymosum woody plant community structure. This study had limited application to rangeland management. However, it can be concluded that grazing of D. cymosum communities should take place during mid-summer, when enough grazing material is available to allow animals to vary their diet. The introduction of animals in poor condition or naïve animals into these lands should be avoided in winter and spring as they will graze non-selectively resulting in D. cymosum poisoning. To utilize these areas as grazing lands, supplements need to be provided to assist in the detoxifications of toxins once ingested. / Dissertation (MSc Agric)--University of Pretoria, 2013. / gm2014 / Plant Production and Soil Science / unrestricted

Cybercrime has increased for several years; both in volume andsophistication. When the capabilities of threat actors increase, techniques andtactics within cybersecurity also need to evolve. AI and machine learninghave potential to prevent and mitigate attacks. This report explores thepossible usage of machine learning for detection of DoS attacks, and furtherinvestigates the potential consequences of adversarial machine Learning. Weuse decision tree model that we train on publicly available DoS attack data.Then we use five computers to perform DoS attacks against a web server andcreate a machine learning model that attempts to detect the attacks based onthe attack's characteristics. In addition, we analyse the consequences ofadversarial machine learning with data poisoning. Our results show thepotential of using machine learning to detect DoS attacks and the dangers ofpoisoning attacks in this context. / Cyberbrottslighet har ökat i både mängd och komplexitet de senaste åren. Närkunskapen och förmågorna hos hotaktörer ökar behöver även teknikerna ochtaktikerna som används inom cybersäkerhet hänga med. AI ochmaskininlärning är verktyg som kan användas för att förebygga attacker. Idetta projekt undersöker vi användning av maskininlärning för att upptäckaDoS attacker. Dessutom undersöker vi de konsekvenserna av angrepp motsjälva maskininlärningsmetoden. Vi börjar med att utföra DoS attacker emotett system och sedan skapar vi en maskininlärningsmodell som försökerupptäcka attackerna utifrån attackernas egenskaper. Sedan undersöker vi vadkonsekvenserna kan bli vid attacker mot maskininlärning via poisoning. Våraresultat visar dels potentialen för maskininlärning vid DoS attacker, och delsfarorna med poisoning.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

In order to fulfil the requirements in the EURO VI standard, regulating emissions from heavy duty vehicles, the exhaust aftertreatment system needs to maintain its efficiency for at least seven years or 700 000 km. In diesel applications the diesel oxidation catalyst (DOC) is located closest to the engine and is thus the most vulnerable to poisoning contaminants, such as phosphorus originating from fuel and oil additives, which deactivates the catalyst. An idea to reduce the impact from phosphorus impurities (recently patented by Scania CV) is to place a low-cost sacrificial substrate, consisting of one or more pillared clay mineral (PILC) with high affinity for phosphorus, upstream the aftertreatment system in order to protect and thus increase the lifetime of the catalytic components which contain platinum group metals. In this work one commercially available and four custom made PILCs, comprising of two conventional type PILCs and two of the type porous clay heterostructures (PCH), were evaluated. The PILCs were exposed to a phosphorus-containing gaseous mixture using a lab-scale experimental setup in order to determine their phosphorus sorption potential. The PILC materials exhibit potential to function as sacrificial substrates for phosphorus in the intended application. It was indicated to be a correlation between increasing iron content (wt%) and increasing phosphorus sorption capability. The most promising material was the custom made Al,Fe-pillared saponite, which was up to twice as effective in trapping phosphorus as the DOC. The commercial sample, the Al-pillared montmorillonite, was only about as efficient as the DOC.

A bacteriological study was made of a number of prepared foods that were bought ready-to-eat, for home consumption, from several food establishments in Dallas, Texas. The purpose of this study was to show whether these foods could be a potential source of food poisoning; whether there are any particular foods that should have greater care than others in order to protect their quality; and whether the bacteriological contamination could have been prevented by strict observance of the city regulations for handling foods.

Submitted in partial fulfillment of the requirement for the degree Master of Science in Emergency Medicine in the Faculty of Health Sciences at the University of Witwatersrand , July 2013 / Background Deliberate self-poisoning (DSP) remains a common method employed for suicide worldwide. Despite its frequent occurrence and the high cost required in its management, only few studies have been carried out on this subject in South Africa. Inadequate research into DSP in South Africa is a great concern as this may inadvertently result in an inadequate knowledge of health professionals on the general approach to victims presenting at emergency departments. This may consequently result in a poor clinical outcome of these cases. This study was aimed at determining the demographics of DSP cases presenting to the emergency department (ED) of Pelonomi hospital and also to enquire into the drugs/agents commonly used, reasons for DSP and the clinical outcome of these cases. Method This was a retrospective, descriptive study which was carried out by going through the hospital clinical records covering a period of eighteen months (1st January 2010 – 30th June 2011). The demographics and deliberate self-poisoning-related information were then collected, using a data collection form. The data was thereafter analysed by using descriptive statistics, calculated for continuous data. Frequencies and percentages were calculated for categorical data. Results Of the 212 DSP cases reviewed, 66% were female. Most patients (86.8%) were single and 65.6% were unemployed. DSP occurred more in the age-group of 20-39 years (68.8%). Majority of the DSP cases (84.4%) occurred in areas associated with poor socio-economic status.Paracetamol was the drug used by majority of these patients (21.7%) for DSP. Other common agents/drugs used were antidepressants (9.4%), antiretrovirals (ARVs) (9.9%) and household chemicals (19.3%). 85 patients (40.1%) took more than one drug/agent. Out of the 81 patients who had the reason for their poisoning stated, 40 patients had relationship disharmony (32 unmarried, 8 married). 15 patients had family issues which mainly resulted from conflicts with parents and grandparents. The medical reasons found amongst 5 patients were HIV infection, cancer and dental problems. Unemployment and post traumatic stress disorder following rape were the other reasons for DSP. The psychosocial problems of 10 patients were not specified. Majority of the patients (59.9%) were discharged in stable conditions. Low GCS (≤8) and hypothermia were common clinical features occurring amongst patients that got admitted. Conclusion DSP is still a common phenomenon, majorly amongst females in the age-group of 20-39 years, with poor quality of life. Relationship disharmony is the most common reason for poisoning. Drug/agents used can only be curtailed to a minimal extent. Prevention through early detection of vulnerable patients and early psychological management should be our goal.

O presente trabalho objetivou avaliar comparativamente a susceptibilidade dos bufalinos e bovinos à intoxicação cúprica acumulativa, por meio do fornecimento de quantidades crescentes de cobre, analisando variáveis clínicas, sangüíneas e os teores de cobre hepático. Com tal objetivo, foram utilizados 20 ruminantes, 10 bovinos (mestiços) e 10 búfalos (raça Murrah) jovens, aleatoriamente distribuídos em seis animais de cada espécie nos grupos que receberam cobre (BOV Cu e BUF Cu) e quatro animais nos grupos controle (BOV e BUF). Diariamente, os grupos BOV Cu e BUF Cu receberam por meio de fistula ruminal 2 mg Cu /kg/PV (CuSO4.5H2O) sendo esta dose acrescida de mais 2 mg/kg/PV a cada semana, até o término do experimento (105 dias). Foram realizadas três biópsias hepáticas (Dia 0 - dia 45 - dia 105) em todos os animais para determinação da concentração de Cu e Zn neste órgão. Quinzenalmente, foi realizado exame clínico, pesagem dos animais e coleta de amostras de sangue. Três bovinos e dois búfalos dos grupos BOV Cu e BUF Cu manifestaram quadro laboratorial e/ou clínico sugestivo de intoxicação cúprica acumulativa (ICA), vindo a sucumbir em seguida. Não existiu diferença entre a freqüência de mortalidade entre os bovinos e búfalos (P > 0,87). Destaca-se a presença de dois quadros clínicos diferentes, o clássico (um bovino e um búfalo) e um atípico (dois bovinos e um búfalo), caracterizado pelo destacado acúmulo de cobre hepático, hiporexia progressiva seguida de anorexia, desidratação, redução dos movimentos de ruminais, oligúria, acentuada apatia e morte, mas sem apresentar hemoglobinúria. Parte dos bovinos e bufalinos se mostraram resistentes à ICA a despeito da administração de altas quantidades cobre. Os teores de cobre hepático nos bovinos com ICA foram superiores, em mais de 100%, aos encontrados nos bufalinos (4389 e 2052 ppm respectivamente). Bovinos com ICA aumentaram a concentração de zinco hepático nas fases finais da intoxicação. A presença de altas atividades séricas de gamaglutamil transferase (GGT) (> 24,6 U/L) e de aspartato aminotransferase (AST) (> 90 U/L) para bovinos e GGT (> 20 U/L) para bufalinos indicaram de maneira efetiva a presença de destacado acúmulo de cobre nos tecidos hepáticos (1000 ppm). Com exceção de um búfalo com o quadro atípico nenhum outro animal apresentou quadro de insuficiência renal. / The main aim of this project is to carry out a comparative study of the susceptibility of cattle (crossbreed) and buffalo (Murrah) to accumulative copper poisoning, by infusion of increasing doses of copper, and studying some clinical and blood variables and the liver Cu concentration. Ten cattle and 10 buffalo yearling steers were randomly distributed into two copper supplemented groups (BOV Cu; BUF Cu; n = 6) and two control groups (BOV; BUF; n = 4). The two former groups received initially 2 mg Cu/kg/BW (as CuSO4..5H2O) daily for a week; every following week, up to the end of the experiment (105th d), this initial dose was increased of 2 mg Cu/kg/BW. For three times during the experiment (day zero, 45thand 105th d) a liver biopsy was carried out to evaluate the degree of copper accumulation in this organ; the body weight and clinical examination was followed weekly, as far as blood samples were withdrawn. Three cattle and two buffaloes supplemented with copper presented clinical picture and/or laboratory findings indicative of accumulative copper poisoning (ACP), and died thereafter. There was no difference in the frequency of mortality between cattle and buffalo (P > 0.87) Two different clinical picture were seen, the classical (one cattle and one buffalo) and one atypical (two cattle and one buffalo) characterized by remarkable high levels of liver copper, progressive hyporexia followed by anorexia, dehydration, severe apathy, decreased rumen movements, oliguria and death. Some of animals were resistant to ACP in spite of high accumulative levels of copper. The liver copper concentration were higher in cattle than buffalo (4.389 and 2.052 ppm, respectively). Cattle with ACP increased their zinc liver concentration at the final stages of the poisoning. The presence of high serum activity of gamma glutamyltransferase (GGT) (> 24.6 U/L) and aspartate aminotransferase (AST) (>90 U/L) for cattle and GGT (> 20 U/L) for buffalo indicated effectively the high accumulation of copper in liver (> 1000 ppm). No poisoned animals developed renal insufficiency, but one buffalo with atypical picture.