Introducción: La Hemorragia Digestiva Alta (HDA) por Úlcera Péptica constituye un problema de emergencia médica y quirúrgica que abarca una gran importancia clínica y sanitaria, a pesar de los cambios que han existido en los últimos años en el conocimiento y manejo de esta patología la tasa de mortalidad global es del 4.5% y la necesidad quirúrgica del 5.5%. La HDA representa el 83% de ingresos en la Unidad de Hemorragia Digestiva (UHD) del HNERM. La Úlcera Péptica Sangrante (UPS) es la causa más frecuente, siendo la Úlcera Duodenal (UD) la que predomina sobre la Gástrica (UG), 30 y 24% respectivamente. La UHD es una unidad especializada en el manejo de estos pacientes críticos, donde el 66% supera los 60 años y el 15% los 80 años. Objetivo: Determinar el perfil clínico, epidemiológico, y terapéutico de los pacientes con diagnóstico endoscópico de Úlcera Péptica Sangrante en el HNERM. Materiales y método: El presente trabajo es un estudio prospectivo-descriptivo realizado en la UHD del HNERM. Se consideraron 41 pacientes que ingresaron con cuadro de Hemorragia Digestiva Alta y diagnóstico endoscópico de Úlcera Péptica Sangrante, entre los meses de Junio del 2005 y Setiembre del 2006. Se evaluaron las características clínicas, epidemiológicas y terapéuticas del total de pacientes reportados. Resultados: La Úlcera Péptica Sangrante predominó en el sexo masculino (85%) y en el grupo de pacientes con edades de 70 a 79 años (36.7%). La Úlcera Duodenal fue la causa más frecuente de sangrado por Úlcera Péptica, siendo más frecuente la melena (53.4%). Un gran número de pacientes presentó antecedentes personales, predominando dentro de estos la ingesta de antiinflamtorios no esteroideos (AINES) en días previos al sangrado (65%), seguido de la presencia de enfermedades concomitantes (61.7%). La UPS se presentó acompañado de dolor abdominal en el 55%, el tipo de dolor abdominal más frecuente fue el ardor (48.3%) y su localización predominante fue el epigastrio (84.8%). El estadios Forrest que predominaron fueron III y IIa, con el 27.8% respectivamente. El tratamiento combinado médico-endoscópico fue el más utilizado en los pacientes con UPS (70%), siendo la medicación antisecretora mayormente administrada, el omeprazol (81.7%) y el tratamiento endoscópico más empleado en nuestro estudio, la inyección de adrenalina 1/10 000 más electrocoagulación con probeta caliente (69%). Conclusiones: La UPS es más frecuente en el sexo masculino y en épocas más tardías de la vida y se asocia frecuentemente a la ingesta previa de AINES. El síntoma digestivo más predominante en su presentación es el dolor abdominal tipo ardor y localizado en el epigastrio. Su causa fundamental es la Úlcera duodenal y se presenta como melena en la gran mayoría de casos. El tratamiento médico-endoscópico es la terapia más utilizada en el manejo y control del sangrado.

While digital coding provides us with numerous benefits, it does have some shortcomings, namely the threshold and the leveling-off effects. These problems do not occur with the use of analog coding, however. Hybrid digital-analog coding systems use both digital and analog coding at the same time to take advantage of the strengths of both coding schemes, while avoiding the problems associated with each. In this work, we propose an HDA system for coding correlates sources. We find the optimal power allocation between the digital and analog parts, and verify the advantages of the suggested system by comparing it to its digital and analog counterparts under different scenarios. / October 2016

Histone deacetylases (HDACs) are an ancient class of enzymes that have been conserved throughout evolution and are found in diverse organisms such as animals, plants, fungi, eubacteria and archaebacteria. In C. elegans, twelve HDACs have been identified so far. These HDACs have been grouped into four different classes (Class I, II, III and IV) based on their cofactor requirements and sequence homologies. hda-1 is one of the three Class I HDACs in C. elegans and plays a role in the morphogenesis of several organs including the vulva. This thesis focuses on the role of hda-1 in vulval morphogenesis. The hermaphrodite vulva has twenty-two cells which can be further divided into seven different cell types: VulAs, VulBls, VulB2s, VulCs and VulDs (secondary great granddaughters), YulEs and VulFs (primary great granddaughters). The analysis of expression pattern of hda-1 revealed that hda-1 is expressed in the progeny of both the primary and secondary vulval precursor cells (VPCs). To examine hda-1 mutant phenotype in detail, I examined the expression pattern of five different vulval cell-type specific markers (cdh-3, zmp-1, ceh-2, egl-17 and daf-6) in hda-1 animals. The results revealed that hda-1 is necessary for proper differentiation of multiple vulval cell types. To study the evolutionary conservation of hda-1 function, I examined the role of hda-1 ortholog in C. briggsae. C. briggsae is a close relative of C. elegans and has almost identical vulval morphology. Knocking down Cbr-hda-1 in C. briggsae animals resulted in defective vulval phenotype. Consistent with this result, the expression of two cell- fate specific markers (C. briggsae orthologs of zmp-1 and egl-17) was found to be altered in Cbr-hda-1 RNAi treated animals. Thus, hda-1 function in the vulva appears to be conserved in these two species. To identify the hda-1 targets in vulval morphogenesis in C. elegans, microarray approach was taken. Two genes fos-1 and lin-29 were identified as putative targets and were examined in some detail. Among the targets identified (these still need to be validated), I focused on fos-1 and lin-29 for detailed investigation. The RNAi-mediated knockdown of hda-1 caused alterations in the expression pattern ofthefos-1 transcript,fos-1b. To examine interaction between fos-1 and lin-29, I used double RNAi approach and examinedfos-1 (RNAi), lin- 29 (RNAi), hda-1 (cw2) animals. It was found that fewer animals exhibit defects in vulval morphology in these animals as compared to fos-1 (RNAi), hda-1 (cw2) animals. While this suggests a possible interaction between lin-29 and hda-1 in the vulva, these results need to be validated by doing additional experiments. In summary, the work described in this thesis demonstrates that hda-1 plays an important role in vulval morphogenesis and regulates the expression of several important genes. Also, the function of hda-1 in C. elegans and C. briggsae is evolutionarily conserved. / Thesis / Master of Science (MSc)

In der molekularen Diagnostik besteht ein Bedarf an schnellen und spezifischen Testsystemen, die entweder für die Labordiagnostik oder in Point of Care-Umgebungen eingesetzt werden können. Um dieses Ziel zu erreichen, stehen die Miniaturisierung und Parallelisierung im Mittelpunkt des Forschungsinteresses. Die führende Methode im Bereich der DNA-Analytik ist derzeit die Realtime-PCR. Dieser Technologie sind hinsichtlich der Multiplexfähigkeit technologischen Hürden gesetzt, da derzeit nur eine Analyse von maximal vier Parametern parallel in einem Versuchsansatz erfolgen kann. Microarrays stellen hingegen die benötigten Voraussetzungen zur Verfügung, um als Werkzeuge für die Multiparameteranalyse in verschiedensten Anwendungsbereichen zu dienen. Ein Schwerpunkt dieser Arbeit war es, Multiplex-PCRs und diagnostische Microarrays zu entwickeln, die für analytische Fragestellungen eine schnelle und zuverlässige Multiparameteranalytik ermöglichen, um die bisherigen Einschränkungen aktueller Nachweisverfahren zu vermeiden. Als Anwendungen wurden zum einen ein Nachweissystem für acht relevante Geflügelpathogene zur Überwachung in der Geflügelzucht, zum anderen ein Nachweissystem zur Identifikation potentiell allergener Lebensmittelinhaltstoffe entwickelt. Neben der Entwicklung geeigneter PCR und Multiplex-PCR-Verfahren sowie spezifischer Microarrays für die Detektion der gesuchten Zielsequenzen stand auch die weiterführende Integration von DNA-Amplifikation und Microarray-Technologie im Fokus dieser Arbeit. Die OnChip-Amplifikation stellt eine Möglichkeit dar, um DNA-Analytik und Detektion in einem Reaktionsschritt zu integrieren. Entsprechend wurden die in der Arbeit entwickelten PCR- und Multiplex-PCR-Verfahren zum Nachweis potentieller allergener Lebensmittelinhaltsstoffe für die OnChip-Amplifikation adaptiert und Reaktionsbedingungen getestet, die eine Multiparameteranalyse auf dem Chip ermöglichen. Die entwickelten OnChip-PCR-Verfahren zeigten eine hohe Spezifität sowohl in Single- als auch in der Multiplex-OnChip-PCR. Eine Sensitivität von 10 Kopien bzw. <10ppm konnte in Single-OnChip-PCRs für den Nachweis allergener Lebensmittelinhaltsstoffe gezeigt werden. In Multiplex-OnChip-PCRs konnten 10-100ppm allergene Verunreinigungen spezifisch in unterschiedlichen Lebensmitteln nachgewiesen werden. Ein weiterer Schritt in Richtung einer möglichen Verwendung im Point of Care-Bereich stellt der Einsatz eines isothermalen Amplifikationsverfahrens dar. Vorteil eines solchen Verfahrens ist die Möglichkeit, auf das ansonsten benötigte Thermocycling zu verzichten. Dies vereinfacht eine Integration der OnChip-Amplifikation in mobile Analysegeräte oder Lab on Chip-Systeme und qualifiziert das Verfahren für den Einsatz in Point of Care-Umgebungen. In dieser Arbeit wurde eine noch junge isothermale Amplifikationsmethode, die helikase-abhängige Amplifikation (HDA), hinsichtlich ihrer Eignung für die Integration auf einem Microarray getestet. Hierfür konnte die bislang erste OnChip-HDA für Einzel- und Duplex-Nachweise von Pathogenen entwickelt werden. / In molecular diagnostics there is a need for fast and specific assay systems that could be used in the clinics and in point of care settings alike. Therefore miniaturisation and parallelisation are in the main focus of current assay development researches. The current gold standard for DNA analytics is the realtime PCR. However, this technology has its restraints in context to multiplex analysis. With the currently available technology an efficient multiplexing is only possible for four different targets per analysed sample. Microarrays in contrast offer the needed multiplex capabilities and have advanced to capable tools used in multiple fields of application. One focus of this work was the integration of Multiplex PCR and microarray technology, developing a microarray capable of analysing multiple parameters in one given sample, circumventing the problems and restraints of the exsisting technologies. As an example microarray assays for two different application fields were developed. One microarray assay for the detection of pathogens in poultry and another microarray assay for the detection of potentially allergenic food ingredients. Single- and Multiplex OnChip-PCR assays for both applications were developed and tested. OnChip-PCRs developed in this work showed high specificity in Single- and Multiplex-OnChip amplifications. The sensitivity was in the range of 10 DNA copies or 10ppm respectively for Single-OnChip-PCR in experiments for the detection of allergenic food contaminations. In Multiplex-OnChip-PCR experiments 100 DNA copies or 100ppm of food contaminents could be detected in different food matrices. A further focus of this work was the adaption of the OnChip amplification for the use in Point of Care settings. Isothermal amplification is a promising approach having the advantage of avoiding the thermocycling needed in the PCR. This opens up certain opportunities for the development of smaller, more flexible mobile diagnostic analysis devices. In this work we have evaluated the helicase dependent amplification (HDA) in terms of usability in OnChip amplification. In this work it was shown for the first time that HDA could be used for the detection of different pathogens in an Duplex-OnChip-PCR, showing the potential of this technology for integration in Point of Care settings.

INTRODUCCIÓN:La hemorragia digestiva alta (HDA) es una urgencia médica frecuente. El pronóstico de los pacientes con HDA, así como la duración de la estancia hospitalaria, vienen determinados en gran medida por la persistencia o recidiva de la hemorragia. En los últimos años, varios autores han desarrollado una serie de sistemas de puntuación, basados en criterios clínicos y endoscópicos, para tratar de predecir el riesgo de resangrado o persistencia. Basándonos en el algoritmo propuesto por Laine en 1994, nuestro equipo introdujo en 1996 un protocolo de alta precoz para pacientes con HDA y bajo riesgo de resangrado. Para la selección de los pacientes con bajo riesgo de resangrado se aplicaron conjuntamente una serie de criterios clínicos y endoscópicos. Los pacientes con bajo riesgo de resangrado fueron incluidos en un protocolo de alta precoz. Las únicas diferencias halladas entre los pacientes candidatos a alta precoz que fueron altados precozmente y los que no, fueron que los últimos presentaban un hematocrito menor al ingreso, mayor número de concentrados de hematíes transfundidos, mayor resangrado intrahospitalario, mayor necesidad de cirugía y mayor número de altas esperadas en fin de semana. El análisis estadístico multivariable mostró que el hematocrito < 25% al ingreso y el alta esperada en fin de semana se asociaban al incumplimiento del protocolo.Una vez demostrado que este protocolo es eficaz en la reducción de la estancia hospitalaria, y seguro, al no afectar a los parámetros de calidad asistencial (resangrado, necesidades de transfusión y cirugía, y mortalidad), nos proponemos valorar la implementación del protocolo.OBJETIVOS:1- Evaluar si, como resultado de la exclusión de las úlceras de tamaño igual o superior a 2 cm como candidatos a alta precoz, disminuye el número de pacientes que resangran.2- Estudiar si la consolidación del protocolo aumenta su cumplimiento (mayor proporción de altas precoces respecto a los candidatos) y modifica la estancia media hospitalaria.3- Evaluar qué factores limitantes del alta precoz influyen en la implementación del protocolo. 4- Examinar si la implementación del protocolo afecta a los parámetros de calidad asistencial. RESULTADOS: 2039 pacientes con HDA ingresan desde Urgencias por HDA en el periodo de estudio. El 48% de los pacientes cumplen criterios de bajo riesgo de resangrado (candidatos a alta precoz).En el periodo de estudio, se incrementa el cumplimiento del protocolo de forma muy significativa, p<0.001, pasando del 76% en 1996 al 95.5% en 2000. La estancia media hospitalaria de los pacientes con bajo riesgo de resangrado se reduce de forma muy significativa, pasando de 3.2 a 1.6 días, con el consiguiente ahorro de recursos, todo ello sin que se afecten negativamente los parámetros de calidad asistencial. CONCLUSIONES1- La exclusión como candidatos a alta precoz de los pacientes con ulcus de tamaño &#8805; 2cm, independientemente de su aspecto endoscópico, produce un descenso del resangrado de éstos, aunque estadísticamente no es significativo.2- Con la implementación del protocolo de alta precoz en los pacientes con bajo riesgo de resangrado se produce un aumento de las altas precoces y un descenso de la estancia media hospitalaria de los enfermos candidatos a alta precoz.3- El hematocrito inicial &#8804; 25% y el alta esperada en fin de semana han dejado de ser factores limitantes para el manejo de los pacientes candidatos a alta precoz, lo que determina un aumento del cumplimiento del protocolo y un descenso de la estancia media de estos pacientes.4- La implementación positiva del protocolo no afecta a los parámetros de calidad asistencial a lo largo del periodo de estudio. / Implementation of a low risk patients with upper gastrointestinal bleeding protocol (1996-2000)Upper gastrointestinal bleeding is a common medical emergency that leads to a high consumption of a medical resources and costs. We introduced in 1996 an early discharge protocol in low risk patients for rebleeding with upper gastrointestinal bleeding. This protocol selected the low risk patients by clinical and endoscopic criteria. The results showed that the protocol was effective and safe. We have studied after if the protocol implementation can reduces more the lenght of hospital stay of low risk patients without have effects on rates of rebleeding, need for surgery, readmission or mortality. We performed a prospective clinical study during a five years period (1996-2000). Overall, 2039 patients with upper gastrointestinal bleeding were treated. 982 (48%) had low risk of rebleeding and were treated by the protocol guideline. The protocol implementation got an excellent results, reducing the length of hospital stay in the low risk patients without negative effects on the rates of rebleeding, need of surgery, readmission or mortality.

Hydrering är en viktig process för att producera produkter med önskade egenskaper samt att uppfylla de lagliga krav som existerar med avseende på miljö och hälsa. Reaktionerna som sker vid hydreringen är katalytiska vilket innebär att förstå sam utnyttja de mest lämpliga katalysatorerna är av yttersta vikt. Avsvavling (HDS) är en av de mest studerade reaktionerna medan avaromatisering (HDA) samt borttagandet av kväve (HDN) är diskuterade samt förstådda i lägre grad. Trots det är aromatiska samt kväverika föreningar naturligt förekommande i matningar till hydreringsreaktorerna där de organiska kväveföreningarna är inhibitorer. I detta arbete är målet att tillverka samt utvärdera några hydreringskatalysatorer med fokus på deras prestanda för HDA och HDN reaktionerna. Den bästa möjliga tekniken idag för tillverkningen av hydreringskatalysatorer utnyttjar kelateringsreagens vid beredningen. Detta har visat sig ha en positiv inverkan på egenskaperna och aktivteten vid hydrering för NiMo-katalysatorer. För att undersöka detta närmare har två typer av katalysatorer tillverkats, en med kelateringsreagens (typ II) och en utan (typ I). Dessa var sedan utvärderade i dess HDA och HDN aktiveter. Katalysatorerna var tillverkade samt karaktäriserade vid KTH och sedan aktiverade via sulfidering samt utvärderade vid Nynas AB. Aktiviteten för de sulfiderade katalysatorerna var utvärderade i ett surrogatsystem bestående av fenantren (PHE) som modell för aromatiska föreningar samt karbazol (CBZ) eller akridin (ACR) som modell för icke-basiskt samt basiskt organisk-kväve. Aktivitetsutvärderingen utfördes i en porlbäddreaktor där aktiviteten undersöktes vid närvarandet samt avsaknandet av de organiska kväveföreningarna. När matningen byttes, en så kallad modeswitch, ändras aktiviteten beroende på de betingelser som undersöktes. Reaktortemperaturen varierade mellan 300 °C och 320 °C vid ett konstant systemtryck på 120 barg. Katalysatornsaktivitet var positivt korrelerad med reaktortemperaturen där en lägre aktivtetuppmättes vid 300 °C jämfört med 320 °C. Det visade sig även att båda typerna av organiskt kväve påverkade aktivteten negativt vid båda undersökta temperaturerna. Utöver det så var de basiska kväveföreningarna mer inhiberande jämfört med de icke-basiska föreningarna för båda katalysatorerna. Inhiberingen orsakad av karbazol visade sig vara helt reversibel medan akridininhiberingen antydde på mer permanenta effekter för typ II katalsatorn. Dessa resultat antyder, trots de preliminära antagandena, att typ I katalysatorn var bättre än typ II katalysatorn. / Hydrotreating processes are of high importance in helping to obtain the desired characteristics of products as well as to comply with the legislation regarding health hazards and environmental pollution. Hydrotreating reactions are catalytic reactions which imply that the understanding and utilization of the most suitable catalysts is crucial. While hydrodesulfurization is a vastly studied branch of hydrotreating, hydrodearomatization (HDA), and hydrodenitrogenation (HDN) processes are less discussed and understood. However, aromatic compounds along with nitrogen-containing inhibitors are naturally present in the hydrotreater feeds. Therefore, the aim of this study was the preparation and evaluation of hydrotreating catalysts with the main focus on HDA and HDN reactions. According to the current state of the art, the utilization of chelating agents during preparation has a positive impact on the characteristics and activity of hydrotreating catalysts therefore NiMo catalysts with (Type II) and without (Type I) a chelating agent were prepared and evaluated towards HDA and HDN reactions. The catalysts were prepared and characterized at KTH and then activated (sulfided) and evaluated at Nynas AB. The activity of the sulfided catalysts was evaluated using surrogate mixture models containing phenanthrene (PHE) as an aromatic compound, and carbazole (CBZ) or acridine (ACR). The latter ones were representing two types of nitrogen-containing inhibitors, non-basic and basic. The activity testing was carried out in a trickle-bed microreactor during three-step experiments in the presence and absence of the organic nitrogen compounds (mode switches). During the mode switches the activity of the catalysts under varying conditions was investigated. The operating temperature of the reactor varied between 300 and 320°C under constant H2 pressure of 120 barg. The catalytic activity was positively correlated with temperature with the catalysts exhibiting lower activities at 300°C than at 320°C. It is noteworthy that the activity of all the catalysts was hindered by the presence of both nitrogen compounds at all temperatures with the basic nitrogen (ACR) being more inhibitory for both catalysts. CBZ inhibition to the HDA reactions showed reversibility, while ACR had a more permanent inhibiting effect in the case of the Type II catalyst. The results indicated that despite the preliminary assumptions, the Type I catalyst outperformed the Type II.

M. Tech. (Department of Chemistry, Faculty of Applied and Computer Science): Vaal University of Technology / Here, we report the synthesis and characterization of silver (Ag) and silver selenide (Ag2Se) nanoparticles using the metal-organic route method. This method involves the reduction of selenium powder and silver nitrate in the presence of trioctylphosphine as a solvent. Tri-n-octylphosphine oxide (TOPO) and hexadecylamine (HDA) were used in the study as capping molecules. The optical properties of the as-prepared nanoparticles were studied using UV-Visible and photoluminescence spectroscopy (PL). Transmission electron microscopy (TEM) and X-ray powder diffraction (XRD) were used to study the structural properties. The effect of capping molecules and temperature were investigated on the growth of the nanoparticles. The prepared nanoparticles seem to depend on the reaction temperature were the increase in temperature led to an increase in particle sizes. The growth of the as-prepared TOPO-capped Ag2Se nanoparticles was influenced by temperature, this was evident when the temperature was increased, the nanoparticles evolved from sphere to hexagonal shape. TOPO-capped nanoparticles showed the tendency of agglomeration with increase in temperature compared to HDA-capped nanoparticles. The X-ray diffraction results showed peaks which were identified as due to α-Ag2Se body centered cubic compound for both TOPO/HDA-capped Ag2Se nanoparticles. Some evidence of impurities were observed in the XRD analysis and indexed to metallic silver. HDA-capped Ag nanoparticles were found to be affected by temperature variation. The prepared nanoparticles were characterized with UV-Vis spectroscopy and transmission electron microscopy. XRD analysis was not performed due to small yield obtained. The absorption spectra of HDA-capped Ag nanoparticles at different temperatures show a surface Plasmon resonance (SPR) band in the regions 418 - 428 nm. Uniform spherical shapes were obtained for both 130 and 190 °C and fewer particles were obtained at 160 °C. The synthesis of TOPO–capped Ag nanoparticles was unsuccessful since none of the particles were isolated from the solution due to its lower capping ability or it may be that TOPO is binding too strongly to Ag. The polymer nanofibres were electrospun using electrospinning technique. Parameters such as concentration and voltage were investigated. These parameters significantly affect the formation of fibre morphology. PVP and PMMA polymers were used for this study. The electrospun composite fibres were characterized using UV-Visible spectroscopy, scanning electron microscopy (SEM), Thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and Fourier transformer infrared (FTIR) spectroscopy. The SEM results show that increasing the polymer concentration resulted in increased fibre diameters. Hence increasing the voltage decreases the fibre diameters. Ag2Se nanoparticles were incorporated into PVP and PMMA and electrospun using electrospinning to produce composite fibres. Their addition into PVP polymer fibres improved the fibre’s uniformity and further decreased their diameters. The SEM of composite fibres for PMMA is not shown. The absorption bands for PVP composites fibres show a blue shift from the pure Ag2Se nanoparticles, whereas the one for PMMA show a red shift from the pure Ag2Se nanoparticles. Both the composite fibres for PVP and PMMA show a blue shift from the bulk of Ag2Se. The XRD analysis of the composite fibres shows no significant effect upon addition of Ag2Se nanoparticles on the amorphous peak of the PVP polymer, whereas on the PMMA, it shows peaks which were due to the face centered cubic phase of Ag. The FTIR spectra of the composite fibres and pure polymers (PVP and PMMA) gave almost identical features. TGA curves show no significant effect on the thermal properties of the PVP polymer and its composites, however, on the PMMA composite fibres it show an increase in the thermal stability of the polymers upon addition of Ag2Se nanoparticles. The study was based on silver nanoparicles and its antibacterial activities. One of the synthetic challenges for silver nanoparticles is their solubility and yield. Selenide was introduced in the study to improve such shortcomings of silver nanoparticles and also for possible improved properties, chemical stability and increased activity against bacteria. The selenide group on the metal also provides stronger chemical interaction between the nanoparticles and the polymer. Therefore, the intension was to use these nanoparticles into polymer fibres for potential use in wound dressing.

This thesis summarizes the methods and major findings of Ni-W(P)/ã-Al2O3 nitride cata-lyst synthesis, characterization, hydrotreating activity, kinetic analysis and correlation of the catalysts activities to their synthesis parameters and properties.<p> The range of parameters for catalyst synthesis were W (15-40 wt%), Ni (0-8 wt%), P (0-5 wt%) and nitriding temperature (TN) (500-900 °C). Characterization techniques used included: N2 sorption studies, chemisorption, elemental analysis, temperature programmed studies, x-ray diffraction, scanning electron microscopy, energy dispersive x-ray, infrared spectroscopy, trans-mission electron microscopy and x-ray absorption near edge structure. Hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrodearomatization (HDA) were performed at: tem-perature (340-380 °C), pressure (6.2-9.0 MPa), liquid hourly space velocity (1-3 h-1) and hydro-gen to oil ratio (600 ml/ml, STP).<p> The predominant species on the catalyst surface were Ni3N, W2N and bimetallic Ni2W3N. The bimetallic Ni-W nitride species was more active than the individual activities of the Ni3N and W2N. P increased weak acid sites while nitriding temperature decreased amount of strong acid sites. Low nitriding temperature enhanced dispersion of metal particles. P interacted with Al2O3 which increased the dispersion of metal nitrides on the catalyst surface. HDN activity in-creased with Ni and P loading but decreased with increase in nitriding temperature (optimum conversion; 60 wt%). HDS and HDA activities went through a maximum with increase in the synthesis parameters (optimum conversions; 88. wt% for HDS and 47 wt% for HDA). Increase in W loading led to increase in catalyst activity. The catalysts were stable to deactivation and had the nitride structure conserved during hydrotreating in the presence of hydrogen sulfide.<p> The results showed good correlation between hydrotreating activities (HDS and HDN) and the catalyst nitrogen content, number of exposed active sites, catalyst particle size and BET surface area.<p> HDS and HDN kinetic analyses, using Langmuir-Hinshelwood models, gave activation energies of 66 and 32 kJ/mol, respectively. There were no diffusion limitations in the reaction process. Two active sites were involved in HDS reaction while one site was used for HDN. HDS and HDN activities of the Ni-W(P)/ã-Al2O3 nitride catalysts were comparable to the corre-sponding sulfides.

This thesis summarizes the methods and major findings of Ni-W(P)/ã-Al2O3 nitride cata-lyst synthesis, characterization, hydrotreating activity, kinetic analysis and correlation of the catalysts activities to their synthesis parameters and properties.<p> The range of parameters for catalyst synthesis were W (15-40 wt%), Ni (0-8 wt%), P (0-5 wt%) and nitriding temperature (TN) (500-900 °C). Characterization techniques used included: N2 sorption studies, chemisorption, elemental analysis, temperature programmed studies, x-ray diffraction, scanning electron microscopy, energy dispersive x-ray, infrared spectroscopy, trans-mission electron microscopy and x-ray absorption near edge structure. Hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrodearomatization (HDA) were performed at: tem-perature (340-380 °C), pressure (6.2-9.0 MPa), liquid hourly space velocity (1-3 h-1) and hydro-gen to oil ratio (600 ml/ml, STP).<p> The predominant species on the catalyst surface were Ni3N, W2N and bimetallic Ni2W3N. The bimetallic Ni-W nitride species was more active than the individual activities of the Ni3N and W2N. P increased weak acid sites while nitriding temperature decreased amount of strong acid sites. Low nitriding temperature enhanced dispersion of metal particles. P interacted with Al2O3 which increased the dispersion of metal nitrides on the catalyst surface. HDN activity in-creased with Ni and P loading but decreased with increase in nitriding temperature (optimum conversion; 60 wt%). HDS and HDA activities went through a maximum with increase in the synthesis parameters (optimum conversions; 88. wt% for HDS and 47 wt% for HDA). Increase in W loading led to increase in catalyst activity. The catalysts were stable to deactivation and had the nitride structure conserved during hydrotreating in the presence of hydrogen sulfide.<p> The results showed good correlation between hydrotreating activities (HDS and HDN) and the catalyst nitrogen content, number of exposed active sites, catalyst particle size and BET surface area.<p> HDS and HDN kinetic analyses, using Langmuir-Hinshelwood models, gave activation energies of 66 and 32 kJ/mol, respectively. There were no diffusion limitations in the reaction process. Two active sites were involved in HDS reaction while one site was used for HDN. HDS and HDN activities of the Ni-W(P)/ã-Al2O3 nitride catalysts were comparable to the corre-sponding sulfides.

In many organisms, the most fundamental event during embryogenesis is differentiating between germline cells and specialized somatic cells. In C. elegans, PIE-1 functions to protect the germline from somatic differentiation and appears to do so by blocking transcription and by preventing chromatin remodeling in the germline during early embryogenesis. Yet the molecular mechanisms by which PIE-1 specifies germline remain poorly understood. Our work shows that SUMOylation facilitates PIE-1-dependent germline maintenance and specification. In vivo SUMO purification in various CRISPR strains revealed that PIE-1 is SUMOylated at lysine 68 in the germline and that this SUMOylation is essential for forming NuRD complex and preserving HDA-1 activity. Moreover, HDA-1 SUMOylation is dependent on PIE-1 and enhanced by PIE-1 SUMOylation, which is required for protecting germline integrity. Our results suggest the importance of SUMOylation in the germline maintenance and exemplify simultaneous SUMOylation of proteins in the same functional pathway.