Concentration and estimated flow of soluble non-ammonia nitrogen entering the omasum of dairy cows as influenced by different protein supplements

Selostus: Valkuaistäydennyksen vaikutus lypsylehmän pötsistä virtaavan liukoisen rehuperäisen typen pitoisuuteen ja määrään sisärehuruokinnalla

Selective catalytic reduction of nitrogen oxides with ammonia in forced unsteady state reactors - Case based reasoning and mathematical model simulation reasoning

The application of forced unsteady-state reactors in case of selective catalytic reduction of nitrogen oxides (NOx) with ammonia (NH3) is sustained by the fact that favorable temperature and composition distributions which cannot be achieved in any steady-state regime can be obtained by means of unsteady-state operations. In a normal way of operation the low exothermicity of the selective catalytic reduction (SCR) reaction (usually carried out in the range of 280-350°C) is not enough to maintain by itself the chemical reaction. A normal mode of operation usually requires supply of supplementary heat increasing in this way the overall process operation cost. Through forced unsteady-state operation, the main advantage that can be obtained when exothermic reactions take place is the possibility of trapping, beside the ammonia, the moving heat wave inside the catalytic bed. The unsteady state-operation enables the exploitation of the thermal storage capacity of the catalyticbed. The catalytic bed acts as a regenerative heat exchanger allowing auto-thermal behaviour when the adiabatic temperature rise is low. Finding the optimum reactor configuration, employing the most suitable operation model and identifying the reactor behavior are highly important steps in order to configure a proper device for industrial applications. The Reverse Flow Reactor (RFR) - a forced unsteady state reactor - corresponds to the above mentioned characteristics and may be employed as an efficient device for the treatment of dilute pollutant mixtures. As a main disadvantage, beside its advantages, the RFR presents the 'wash out' phenomena. This phenomenon represents emissions of unconverted reactants at every switch of the flow direction. As a consequence our attention was focused on finding an alternative reactor configuration for RFR which is not affected by the incontrollable emissions of unconverted reactants. In this respect the Reactor Network (RN) was investigated. Its configuration consists of several reactors connected in a closed sequence, simulating a moving bed by changing the reactants feeding position. In the RN the flow direction is maintained in the same way ensuring uniformcatalyst exploitation and in the same time the 'wash out' phenomena is annulated. The simulated moving bed (SMB) can operate in transient mode giving practically constant exit concentration and high conversion levels. The main advantage of the reactor network operation is emphasizedby the possibility to obtain auto-thermal behavior with nearly uniformcatalyst utilization. However, the reactor network presents only a small range of switching times which allow to reach and to maintain an ignited state. Even so a proper study of the complex behavior of the RN may give the necessary information to overcome all the difficulties that can appear in the RN operation. The unsteady-state reactors complexity arises from the fact that these reactor types are characterized by short contact times and complex interaction between heat and mass transportphenomena. Such complex interactions can give rise to a remarkable complex dynamic behavior characterized by a set of spatial-temporal patterns, chaotic changes in concentration and traveling waves of heat or chemical reactivity. The main efforts of the current research studies concern the improvement of contact modalities between reactants, the possibility of thermal wave storage inside the reactor and the improvement of the kinetic activity of the catalyst used. Paying attention to the above mentioned aspects is important when higher activity even at low feeding temperatures and low emissions of unconverted reactants are the main operation concerns. Also, the prediction of the reactor pseudo or steady-state performance (regarding the conversion, selectivity and thermal behavior) and the dynamicreactor response during exploitation are important aspects in finding the optimal control strategy for the forced unsteady state catalytic tubular reactors. The design of an adapted reactor requires knowledge about the influence of its operating conditions on the overall process performance and a precise evaluation of the operating parameters rage for which a sustained dynamic behavior is obtained. An apriori estimation of the system parameters result in diminution of the computational efforts. Usually the convergence of unsteady state reactor systems requires integration over hundreds of cycles depending on the initial guess of the parameter values. The investigation of various operation models and thermal transfer strategies give reliable means to obtain recuperative and regenerative devices which are capable to maintain an auto-thermal behavior in case of low exothermic reactions. In the present research work a gradual analysis of the SCR of NOx with ammonia process in forced unsteady-state reactors was realized. The investigation covers the presentationof the general problematic related to the effect of noxious emissions in the environment, the analysis of the suitable catalysts types for the process, the mathematical analysis approach for modeling and finding the system solutions and the experimental investigation of the device found to be more suitable for the present process. In order to gain information about the forced unsteady state reactor design, operation, important system parameters and their values, mathematical description, mathematicalmethod for solving systems of partial differential equations and other specific aspects, in a fast and easy way, and a case based reasoning (CBR) approach has been used. This approach, using the experience of past similarproblems and their adapted solutions, may provide a method for gaining informations and solutions for new problems related to the forced unsteady state reactors technology. As a consequence a CBR system was implemented and a corresponding tool was developed. Further on, grooving up the hypothesis of isothermal operation, the investigation by means of numerical simulation of the feasibility of the SCR of NOx with ammonia in the RFRand in the RN with variable feeding position was realized. The hypothesis of non-isothermal operation was taken into account because in our opinion ifa commercial catalyst is considered, is not possible to modify the chemical activity and its adsorptive capacity to improve the operation butis possible to change the operation regime. In order to identify the most suitable device for the unsteady state reduction of NOx with ammonia, considering the perspective of recuperative and regenerative devices, a comparative analysis of the above mentioned two devices performance was realized. The assumption of isothermal conditions in the beginningof the forced unsteadystate investigation allowed the simplification of the analysis enabling to focus on the impact of the conditions and mode of operation on the dynamic features caused by the trapping of one reactant in the reactor, without considering the impact of thermal effect on overall reactor performance. The non-isothermal system approach has been investigated in order to point out the important influence of the thermal effect on overall reactor performance, studying the possibility of RFR and RN utilization as recuperative and regenerative devices and the possibility of achieving a sustained auto-thermal behavior in case of lowexothermic reaction of SCR of NOx with ammonia and low temperature gasfeeding. Beside the influence of the thermal effect, the influence of the principal operating parameters, as switching time, inlet flow rate and initial catalyst temperature have been stressed. This analysis is important not only because it allows a comparison between the two devices and optimisation of the operation, but also the switching time is the main operating parameter. An appropriate choice of this parameter enables the fulfilment of the process constraints. The level of the conversions achieved, the more uniform temperature profiles, the uniformity ofcatalyst exploitation and the much simpler mode of operation imposed the RN as a much more suitable device for SCR of NOx with ammonia, in usual operation and also in the perspective of control strategy implementation. Theoretical simplified models have also been proposed in order to describe the forced unsteady state reactors performance and to estimate their internal temperature and concentration profiles. The general idea was to extend the study of catalytic reactor dynamics taking into account the perspectives that haven't been analyzed yet. The experimental investigation ofRN revealed a good agreement between the data obtained by model simulation and the ones obtained experimentally.

Separation of ammonia and carbon dioxide by adsorption

Tässä työssä on tutkittu ammoniakin ja hiilidioksidin erottamista adsorptio prosessilla ja suunniteltiin paineen muunteluun perustuvan adsorptioprosessin (PSA) käyttöä. Työn tarkoituksena oli laskea adsorptioon perustuvan prosessin kannattavuus melamiinitehtaan poistokaasujen erotuksessa. Tätä varten työssä suunniteltiin tehdasmitta-kaavainen prosessi ja arvioitiin sen kannattavuus. Työssä mitattiin adsorptiotasapainot, joiden perusteella sovitettiin sopiva kokeellinen adsorptioisotermi. Adsorptioisotermi lisättiin simulointiohjelmaan, jonka avulla suunniteltiin kaksi vaihtoehtoista pilot laitteistoa kaasujen erottamiseksi. Toisella pilot laitteistolla saadaan mitattua vain läpäisykäyrät, mutta paremmalla versiolla saadaan myös tietoa erotettujen komponenttien puhtaudesta. Suunnittelun tärkeimpiä lähtökohtia on molempien komponenttien mahdollisimman korkea puhtaus ja talteenottoaste. Täysimittakaavainen tehdas suunniteltiin simulointiohjelmiston avulla kahdelle eri kapasiteetille ja arvioitiin niiden kustannukset ja kannattavuus. Adsorptioprosessit osoittautuivat kannattaviksi kaasuseoksen erottamisessa kummassakin tapauksessa

Bisphosphonate Inhibition of Prostate Cancer Cell Invasion, Migration and Cytoskeletal Organization

Metastatic bone lesions are commonly associated with prostate cancer affecting approximately 60-80% of the patients. The progression of prostate cancer into an advanced stage is a complex process and its molecular mechanisms are poorly understood. So far, no curative treatment is available for advanced stages of prostate cancer. Bisphosphonates (BPs) are synthetic pyrophosphate analogues, which are used as therapeutics for various metabolic bone diseases because of their ability to inhibit osteoclastic bone resorption. Nitrogen-containing bisphosphonates block the function of osteoclasts by disturbing the vesicular traffic and the mevalonate pathway -related enzymes, for example farnesyl diphosphate synthase, which is involved in post-translational isoprenylation of small GTPases. In addition, the anti-proliferative, anti-invasive and pro-apoptotic effects of nitrogen-containing bisphosphonates on various cancer cell lines have been reported. The aim of this thesis work was to clarify the effects of bisphosphonates on prostate cancer cells, focusing on the mechanisms of adhesion, invasion and migration. Furthermore, the role of the mevalonate pathway and prenylation reactions in invasion and regulation of the cytoskeleton of prostate cancer cells were examined. Finally, the effects of alendronate on cytoskeleton- and actin-related proteins in prostate cancer cells were studied in vitro and in vivo. The results showed that the nitrogen-containing bisphosphonate alendronate inhibited the adhesion of prostate cancer cells to various extracellular matrix proteins and migration and invasion in vitro. Inhibition of invasion and migration was reversed by mevalonate pathway intermediates. The blockage of the prenylation transferases GGTase I and FTase inhibited the invasion, migration and actin organization of prostate cancer cells. The marked decrease of cofilin was observed by the prenylation inhibitors used. Inhibition of GGTase I also disrupted the regulation of focal adhesion kinase and paxillin. In addition, alendronate disrupted the cytoskeletal organization and decreased the level of cofilin in vitro and in vivo. The decrease of the cofilin level by alendronate could be one of the key mechanisms behind the observed inhibition of migration and invasion. Based on the effects of nitrogen-containing bisphosphonates on tumor cell invasion and cytoskeletal organization, they can be suggested to be developed as therapeutics for inhibiting prostate cancer metastasis.

Identification and characterisation of a novel adhesin of Streptococcus suis and its use as a target of adhesion inhibition and bacterial detection

Streptococcus suis is an important pig pathogen but it is also zoonotic, i.e. capable of causing diseases in humans. Human S. suis infections are quite uncommon but potentially life-threatening and the pathogen is an emerging public health concern. This Gram-positive bacterium possesses a galabiose-specific (Galalpha1−4Gal) adhesion activity, which has been studied for over 20 years. P-fimbriated Escherichia coli−bacteria also possess a similar adhesin activity targeting the same disaccharide. The galabiose-specific adhesin of S. suis was identified by an affinity proteomics method. No function of the protein identified was formerly known and it was designated streptococcal adhesin P (SadP). The peptide sequence of SadP contains an LPXTG-motif and the protein was proven to be cell wall−anchored. SadP may be multimeric since in SDS-PAGE gel it formed a protein ladder starting from about 200 kDa. The identification was confirmed by producing knockout strains lacking functional adhesin, which had lost their ability to bind to galabiose. The adhesin gene was cloned in a bacterial expression host and properties of the recombinant adhesin were studied. The galabiose-binding properties of the recombinant protein were found to be consistent with previous results obtained studying whole bacterial cells. A live-bacteria application of surface plasmon resonance was set up, and various carbohydrate inhibitors of the galabiose-specific adhesins were studied with this assay. The potencies of the inhibitors were highly dependent on multivalency. Compared with P-fimbriated E. coli, lower concentrations of galabiose derivatives were needed to inhibit the adhesion of S. suis. Multivalent inhibitors of S. suis adhesion were found to be effective at low nanomolar concentrations. To specifically detect galabiose adhesin−expressing S. suis bacteria, a technique utilising magnetic glycoparticles and an ATP bioluminescence bacterial detection system was also developed. The identification and characterisation of the SadP adhesin give valuable information on the adhesion mechanisms of S. suis, and the results of this study may be helpful for the development of novel inhibitors and specific detection methods of this pathogen.

Ammonia regeneration in nickel matte chloride leaching

Ammonia can be used as a pH controller in chloride-based metal recovery processes. In chloride conditions, ammonia reacts to ammonium chloride which can be regenerated back to ammonia with lime. Although the regeneration process itself has been known for a long time, the concentrations, non-reacting species, conditions, and even goals are different when comparing the ammonia regeneration process in different industries. The main objective of this thesis was to study the phenomena, equipment, and challenges in ammonia regeneration in the nickel process and to make a preliminary process design. The study concentrated on the regeneration and recovery units. The thesis was made by process simulation and laboratory tests using the current processes as initial information. The results were combined from all of the information obtained during the studies to provide a total process solution, which can be used as a basis when designing an ammonia regeneration process to be used in industry. In particular, it was possible to determine ammonia recovery with a stripping column and the achievement of the desired ammonia water product within the scope of this thesis. The required mass flows and process conditions were also determined. The possible challenges and solutions or further studies to overcome them were provided as well to ease the prediction and design of the ammonia regeneration process in the future. On the basis of the results of this thesis, the ammonia regeneration process can be developed further and implemented in the nickel chloride leaching process.

Selective inhibition of human tankyrases

Tankyrases belong to the Diphtheria toxin-like ADP-ribosyltransferase (ARTD) enzyme superfamily, also known as poly(ADP-ribose) polymerases (PARPs). They catalyze a covalent post-translational modification reaction where they transfer ADP-ribose units from NAD+ to target proteins. Tankyrases are involved in many cellular processes and their roles in telomere homeostasis, Wnt signaling and in several diseases including cancers have made them interesting drug targets. In this thesis project, selective inhibition of human tankyrases was studied. A homogeneous fluorescence-based assay was developed to screen the compound libraries. The assay is inexpensive, operationally easy, and performs well according to the statistical analysis. Assay suitability was confirmed by screening a natural product library. Flavone was identified as the most potent inhibitor in the library and this motivated us to screen a larger flavonoid library. Results showed that flavones were indeed the best inhibitor of tankyrases among flavonoids. To further study the structure-activity relationship, a small library of flavones containing single substitution was screened and potency measurements allowed us to generate structure-activity relationship. Compounds containing substitutions at 4´-position were more potent in comparison to other substitutions, and importantly, hydrophobic groups improved isoenzyme selectivity as well as the potency. A flavone derivative containing a hydrophobic isopropyl group (compound 22), displayed 6 nM potency against TNKS1, excellent isoenzyme selectivity and Wnt signaling inhibition. Protein interactions with compounds were studied by solving complex crystal structures of the compounds with TNKS2 catalytic domain. A novel tankyrase inhibitor (IWR-1) was also crystallized in complex with TNKS2 catalytic domain. The crystal structure of TNKS2 in complex with IWR-1 showed that the compound binds to adenosine site and it was the first known ARTD inhibitor of this kind. To date, there is no structural information available about the substrate binding with any of the ARTD family members; therefore NAD+ was soaked with TNKS2 catalytic domain crystals. However, analysis of crystal structure showed that NAD+ was hydrolyzed to nicotinamide. Also, a co-crystal structure of NAD+ mimic compound, EB-47, was solved which was used to deduce some insights about the substrate interactions with the enzyme. Like EB-47, other ARTD1 inhibitors were also shown to inhibit tankyrases. It indicated that selectivity of the ARTD1 inhibitors should be considered as some of the effects in cells could come from tankyrase inhibition. In conclusion, the study provides novel information on tankyrase inhibition and presents new insight into the selectivity and potency of compounds.

Adsorption of arsenic from ammonia containing waste water by ferrous hydroxide waste

Arsenic is a toxic substance. The amount of arsenic in waste water is a raising problem because of increasing mining industry. Arsenic is connected to cancers in areas where arsenic concentration in drinking water is higher than recommendations. The main object in this master’s thesis was to research how ferrous hydroxide waste material is adsorbed arsenic from ammonia containing waste water. In this master’s thesis there is two parts: theoretical and experimental part. In theoretical part harmful effects of arsenic, theory of adsorption, isotherms modeling of adsorption and analysis methods of arsenic are described. In experimental part adsorption capacity of ferrous hydroxide waste material and adsorption time with different concentrations of arsenic were studied. Waste material was modified with two modification methods. Based on experimental results the adsorption capacity of waste material was high. The problem with waste material was that at same time with arsenic adsorption sulfur was dissolving in solution. Waste material was purified from sulfur but purification methods were not efficient enough. Purification methods require more research.