Haematology instruments using optical and fluorescence techniques have improved the platelet count in domestic animals. There are still some difficulties present, especially when counting cat thrombocytes due to their ability to aggregate and the occurrence of large platelets. The objective of this study was to evaluate and compare the platelet count, mean platelet volume and platelet crit in dogs, horses and cats on Advia 2120 and Sysmex XT-2000iV. Fresh blood samples from 64 dogs, 40 horses and 39 cats with various medical conditions were analysed on both instruments. Manual blood smears of all feline samples were scrutiniously analysed to evaluate the aggregation warning flag from Advia. There was good agreement between the instruments for the optical platelet count in dogs and cats. Slightly higher values were reported from Advia. Samples from horses presented poor correlations for all studied parameters. Platelet clumps appeared in 70% of the 37 scrutinized feline blood smears, while 46% of the samples generated aggregation warning flags from the Advia instrument. Advia and Sysmex showed good agreement for platelet counts in blood from dogs and cats. Mean platelet volume and platelet crit need further evaluation before conclusions can be made concerning their clinical relevance. The sensitivity of the platelet aggregation warning flag from the Advia instument needs further elevation.

No description available.

Organic light-emitting devices (OLEDs) have attracted significant attention because of their unique advantages for flat panel display applications. However, the relatively limited electroluminescence (EL) stability of blue emitting OLEDs continues to limit the commercialization of full color OLED displays. In most cases, the decrease in EL efficiency is also accompanied by a loss in blue color purity. Thus, the understanding of the degradation mechanisms of both the EL efficiency loss and color purity loss and the corresponding solutions to device degradation are required. In this thesis, electrical aging mechanism in anthracene-based OLEDs is investigated by using a number of techniques, including delayed EL measurements. The studies reveal that electrical aging is associated with an increasing concentration of an intermolecular species with a weak characteristic luminescence at around 535 nm. This species is capable of trapping charges, and thus plays a role as an electron-hole recombination center with prolonged electrical driving. Weak green luminescence from this species leads to an increased green/blue emission ratio, and causes the color purity loss in aged devices. The results also suggest that this species is also efficient in dissipating excitation energy non-radiatively, hence is capable of quenching singlet excitons in anthracene-based OLEDs, contributing to the observed efficiency loss with electrical aging. Moreover, the photo-stability of the organic/metal cathode interface in OLEDs is studied. Irradiating OLEDs by external illumination is found to result in a gradual increase in driving voltage and decrease in EL efficiency. This photo-induced degradation in device performance is found to be caused by changes at the organic/metal cathode interface that lead to a deterioration in electron injection. Evidence of photodegradation of the same interface, inherently, by device own EL, is also reported. The results uncover an important degradation mechanism in OLEDs and shed the light on a phenomenon that might limit the stability of other organic optoelectronic and photovoltaic devices.

1. Ištyrus homocisteino koncentraciją kraujo serume ir trombocitų agregaciją kraujo plazmoje su pagrindiniais natūriniais agregantais (adenozino difosfatas, adrenalinas, kolagenas) sergančiųjų ūminiais galvos smegenų kraujotakos sutrikimais, nustatyta koreliacija tarp:  padidėjusios homocisteino koncentracijos ir insulto su dideliu neurologiniu deficitu, išeminės širdies ligos, kreatinino ir C-reaktyviojo baltymo koncentracijų;  vidinės miego arterijos stenozės laipsnio ir homocisteino koncentracijos kraujo serume;  homocisteino koncentracijos kraujo serume ir amžiaus;  padidintos homocisteino koncentracijos ir pasikartojančio insulto, todėl homocisteino koncentracijos lygis gali būti panaudotas kaip prognostinis rodiklis naujam ar kartotiniam ūminiam galvos smegenų kraujotakos sutrikimui išsivystyti. 2. Trombocitų agregacija turtingoje trombocitais plazmoje ūminio išeminio galvos smegenų kraujotakos sutrikimo periode statistiškai patikimai padidėja insultu sergančiųjų grupėje, nepriklausomai nuo susirgimo sunkumo. 3. Profilaktinės aspirino dozės hiperhomocisteinemijos fone dalį ligonių neapsaugo nuo išeminio insulto išsivystymo. Aspirino vartojimas turi veiksmingesnį antiagregacinį poveikį moterims, nei vyrams: moterų plazmoje trombocitų agregacijos intensyvumas buvo žemesnis su visais agonistais, o vyrų trombocitai, atvirkščiai, į juos reagavo viršnorminiu atsaku. 4. Išeminiu insultu sirgusių ligonių kraujyje dažniau randami policitemija, padidėjęs leukocitų... [toliau žr. visą tekstą] / 1. When examining homocysteine concentration in blood serum and platelet aggregation in plasma using nature aggregants (adenosine diphosphate, adrenalin, collagen) in patients with acute cerebrovascular disorders, the positive corelation was found between the following parameters:  the elevated amount of homocysteine and stroke with the high neurological deficit, ischemic heart disease, creatinin and C-reactive protein concentrations;  the degree of internal carotid artery stenosis and homocysteine concentration in blood serum;  homocysteine concentration in blood serum and age;  elevation of homocysteine concentration and recurrent stroke, thus, homocysteine concentration may be a predisposing indicator to the development of new or recurrent acute cerebrovascular disorder. 2. Platelet aggreagation in platelet-rich plasma during the period of acute cerebrovascular disorder statistically significantly increases in stroke group independent upon severity of illness. 3. Preventive aspirin doses in the light of hyperhomocysteinemia do not protect a certain part of patients from ischemic stroke development (among the debatable causes of this outcome may be aspirin resistance). Aspirin intake has a more effective antiaggregate influence on women than men: the intensity of platelet aggregation in women plasma was lower using all agonists, while in men, on the contrary, platelets responded by reaching levels above normal. 4. The patients, who experienced ischemic stroke... [to full text]

Wireless Sensor Networks (WSNs) have significant potential in many application domains, and are poised for growth in many markets ranging from agriculture and animal welfare to home and office automation. Although sensor network deployments have only begun to appear, the industry still awaits the maturing of this technology to realize its full benefits. The main constraints to large scale commercial adoption of sensor networks are the lack of available network management and control tools for determining the degree of data aggregation prior to transforming it into useful information, localizing the sensors accurately so that timely emergency actions can be taken at exact location, and scheduling data packets so that data are sent based on their priority and fairness. Moreover, due to the limited communication range of sensors, a large geographical area cannot be covered, which limits sensors application domain. Thus, we investigate a scalable and flexible WSN architecture that relies on multi-modal nodes equipped with IEEE 802.15.4 and IEEE 802.11 in order to use a Wi-Fi overlay as a seamless gateway to the Internet through WiMAX networks. We focus on network management approaches such as sensors localization, data scheduling, routing, and data aggregation for the WSN plane of this large scale multimodal network architecture and find that most existing approaches are not scalable, energy efficient, and fault tolerant. Thus, we introduce an efficient approach for each of localization, data scheduling, routing, and data aggregation; and compare the performance of proposed approaches with existing ones in terms of network energy consumptions, localization error, end-to-end data transmission delay and packet delivery ratio. Simulation results, theoretical and statistical analysis show that each of these approaches outperforms the existing approaches. To the best of our knowledge, no integrated network management solution comprising efficient localization, data scheduling, routing, and data aggregation approaches exists in the literature for a large scale WSN. Hence, we e±ciently integrate all network management components so that it can be used as a single network management solution for a large scale WSN, perform experimentations to evaluate the performance of the proposed framework, and validate the results through statistical analysis. Experimental results show that our proposed framework outperforms existing approaches in terms of localization energy consumptions, localization accuracy, network energy consumptions and end-to-end data transmission delay.

Calpains are a family of intracellular cysteine proteases activated by calcium. They participate in many processes including cell motility, cell cycle progression and cell death, in response to calcium signaling. Because calpain over-activation as a result of calcium dysregulation is a contributing factor to many disease states, these enzymes are important therapeutic targets. Within the cell, calpains 1 and 2 are regulated by the protein inhibitor calpastatin. This unstructured protein is specific for calpain, binds tightly, and recognizes only the activated form of the enzyme. Detailed kinetic data obtained using surface plasmon resonance allowed the association and dissociation rates of each of the four calpastatin inhibitory domains to be measured. Based on this, inhibitory domain 4 was selected to be co-crystallized bound to calpain 2. The X-ray crystal structure of this complex provided both the first view of the active enzyme, as well as the first view of how it is inhibited. Calpastatin wraps around the enzyme making contact with each domain. It lies in the active site as a contiguous polypeptide chain and escapes cleavage by forming a loop away from the catalytic cysteine. In addition to inhibiting substrate cleavage, calpastatin protects calpain in two ways; it prevents autoproteolysis, and it prevents calcium-dependent aggregation. The crystal structure of the calpastatin:calpain complex revealed no obvious reason for this stabilization. To elucidate how this protection occurs, peptides were synthesized corresponding to conserved subdomains of calpastatin. Surprisingly, each peptide alone was capable of preventing aggregation in vitro, by blocking hydrophobic patches exposed upon activation. The increased hydrophobic surface of the activated enzyme may alter calpain’s affinity for other proteins such as substrates. By binding across many domains of calpain, calpastatin could act to block protein-protein interactions. These studies have characterized calpastatin’s interaction with calpain, which will further our understanding of the enzyme’s regulation and aid in the development of better calpain inhibitors. / Thesis (Ph.D, Biochemistry) -- Queen's University, 2010-04-29 15:27:16.208

No description available.

This dissertation consists of three essays. In the first essay, I estimate a high dimensional covariance matrix of returns for 88 individual stocks from the S&P 100 index, using daily return data for 1995-2005. This study applies the two-step estimator of the dynamic conditional correlation multivariate GARCH model, proposed by Engle (2002b) and Engle and Sheppard (2001) and applies variations of this model. This is the first study estimating variances and covariances of returns using a large number of individual stocks (e.g., Engle and Sheppard (2001) use data on various aggregate sub-indexes of stocks). This avoids errors in estimation of GARCH models with contemporaneous aggregation of stocks (e.g. Nijman and Sentana 1996; Komunjer 2001). Second, this is the first multivariate GARCH adopting a systematic general-to-specific approach to specification of lagged returns in the mean equation. Various alternatives to simple GARCH are considered in step one univariate estimation, and econometric results favour an asymmetric EGARCH extension of Engle and Sheppard’s model. In essay two, I aggregate a variance-covariance matrix of return risk (estimated using DCC-MVGARCH in essay one) to an aggregate index of return risk. This measure of risk is compared with the standard approach to measuring risk from a simple univariate GARCH model of aggregate returns. In principle the standard approach implies errors in estimation due to contemporaneous aggregation of stocks. The two measures are compared in terms of correlation and economic values: measures are not perfectly correlated, and the economic value for the improved estimate of risk as calculated here is substantial. Essay three has three parts. The major part is an empirical study of the aggregate risk return tradeoff for U.S. stocks using daily data. Recent research indicates that past risk-return studies suffer from inadequate sample size, and this suggests using daily rather than monthly data. Modeling dynamics/lags is critical in daily models, and apparently this is the first such study to model lags correctly using a general to specific approach. This is also the first risk return study to apply Wu tests for possible problems of endogeneity/measurement error for the risk variable. Results indicate a statistically significant positive relation between expected returns and risk, as is predicted by capital asset pricing models. Development of the Wu test leads naturally into a model relating aggregate risk of returns to economic variables from the risk return study. This is the first such model to include lags in variables based on a general to specific methodology and to include covariances of such variables. I also derive coefficient links between such models and risk-return models, so in theory these models are more closely related than has been realized in past literature. Empirical results for the daily model are consistent with theory and indicate that the economic and financial variables explain a substantial part of variation in daily risk of returns. The first section of this essay also investigates at a theoretical and empirical level several alternative index number approaches for aggregating multivariate risk over stocks. The empirical results indicate that these indexes are highly correlated for this data set, so only the simplest indexes are used in the remainder of the essay.

IR-Spektren von neutralen Na(H2O)n-Clustern wurden im OH-Streckschwingungsbereich (2800 – 3800 cm-1) größenselektiv bis n=575±25 gemessen. Die Infrarot-anregungsmodulierte, durch chemische Vorionisation verstärkte Photoionisation beruht auf dem Effekt einer Signalverstärkung durch IR-Absorption bei schwellennaher Photoionisation. Die Strukturinformation kann anhand eines Vergleichs mit quantenchemischen Rechnungen gewonnen werden. Die mit dieser Methode erhaltenen IR-Spektren können für verschiedene Größenbereiche mit durch andere Verfahren generierten Spektren verglichen werden. Für mittlere Clustergrößen (~n=20-50) sind die erhaltenen IR-Signaturen sehr ähnlich zu RIDIR-Spektren von phenoldotierten Clustern. Die Spektren großer amorpher Cluster (n=250) sind vergleichbar mit denen ionischer Cluster. Die Variation der Expansionsbedingungen (z. B. die Änderung des Trägergases) beeinflusst nicht nur das Einsetzten der Kristallisation (beginnend zwischen n=200 und n=400), sondern auch die Isomerenzusammensetzung für kleinere Clustergrößen. Auf dieser Grundlage wurden Strukturen für die Größen (H2O)20, (H2O)25 und (H2O)32 untersucht.

Light scattering is a powerful characterization tool for determining shape, size, and size distribution of fine particles, as well as complex, irregular structures of their aggregates. Small angle static light scattering and elliptically polarized light scattering techniques produce accurate results and provide real time, non-intrusive, and in-situ observations on prevailing process conditions in three-dimensional systems. As such, they complement conventional characterization tools such as SEM and TEM which have their known disadvantages and limitations. In this study, we provide a thorough light scattering analysis of colloidal tungsten trioxide (WO3) nanoparticles in the shape of irregular nanospheres and cylindrical nanowires, and of the resulting aggregate morphologies. Aggregation characteristics as a function of primary particle geometry, aspect ratio of nanowires, and the change in dispersion stability in various polar solvents without the use of dispersants are monitored over different time scales and are described using the concepts of fractal theory. Using forward scattered intensities, sedimentation rates as a result of electrolyte addition and particle concentration at low solution pH are quantified, in contrast to widely reported visual observations, and are related to the aggregate structure in the dispersed phase. For nanowires of high aspect ratios, when aggregate structures cannot directly be inferred from measurements, an analytical and a quasiexperimental method are used.