Tools for single cell proteomics

Despite recent advances that offer control of single cells, in terms of manipulation and sorting and the ability to measure gene expression, the need to measure protein copy number remains unmet. Measuring protein copy number in single cells and related quantities such as levels of phosphorylation and protein-protein interaction is the basis of single cell proteomics. A technology platform to undertake the analysis of protein copy number from single cells has been developed. The approach described is ‘all-optical’ whereby single cells are manipulated into separate analysis chambers using an optical trap; single cells are lysed by mechanical shearing caused by laser-induced microcavitation; and the protein released from a single cell is measured by total internal reflection microscopy as it is bound to micro-printed antibody spots within the device. The platform was tested using GFP transfected cells and the relative precision of the measurement method was determined to be 88%. Single cell measurements were also made on a breast cancer cell line to measure the relative levels of unlabelled human tumour suppressor protein p53 using a chip incorporating an antibody sandwich assay format. This demonstrates the ability count protein copy number from single cells in a manner which could be applied in principle to any set of proteins and for any cell type without the need for genetic engineering. Metabolism can undergo alteration in diseases such as cancer and heart failure and also as cells differentiate during development. In order to assess how it may inform a proteomic measurement, multidimensional two-photon fluorescence metabolic imaging is conducted on a cultured cancer cell line, primary adult rat cardiomyocytes and human embryonic stem cells. By measuring the parameters of fluorescence such as intensity and lifetime of the autofluorescent metabolic co-factors NADH and FAD, it was found to be possible to contrast cells under various conditions and metabolic stimuli. In particular, human embryonic stem cells were able to be contrasted at 3 stages of development as they underwent differentiation into embryonic stem cell derived cardiomyocytes. Metabolic imaging provides a non-destructive method to monitor cellular metabolic activity with high resolution. This is complimentary to the single cell proteomic platform and the convergence of both techniques holds promise in future investigations into how metabolism influences cell function and the proteome in development and disease

Influence of Xylitol on Properties of a Daptomycin-Loaded Acrylic Bone Cement

The purposes of the present work were to determine 1) the optimum amount of xylitol to use in a daptomycin-xylitol-Orthoset® 1 cement; and 2) the influence of xylitol on the elution mechanism of this cement. In support of these purposes, five properties of the xylitol-daptomycin-loaded cement (with four different xylitol loadings) were determined: daptomycin elution rate, daptomycin diffusion coefficient, index of the activity of the daptomycin eluate against S. aureus, rate of polymerization of the cement at 37ºC, and diffusion coefficient of phosphate buffered saline into the cement specimen. It was found that the optimum xylitol loading is 4 wt./wt.% (equivalent to 2 g of xylitol mixed with 1.4 g of daptomycin and 40 g of cement powder) and, regardless of the amount of xylitol in the cement, the applicable daptomycin elution mechanism is initial burst followed by slow Fickian release

CONSTRAINTS ON IZĀFA IN SORANI KURDISH

This study examines the distribution and the status of the izāfa particle in Sorani Kurdish (Central Kurdish). It uses a corpus-based analysis to investigate the forms and the pattern of distribution of the izāfa particle in Sorani, a dominant dialect of Kurdish among the Western Iranian languages. The study details an investigation of the appearance of izāfa in various NPs using a variety of data mostly from the corpus but supplemented by the grammaticality judgments of native speakers. I show that next to parallel properties seen in other Western Iranian languages, Sorani Kurdish izāfa shows a form alternation. I examine the morphological status of the izāfa and other nominal morphological features in Kurdish as well as the sensitivity of izāfa form variation to specificity in Kurdish NPs. I argue that the differences and distributional incoherence of the izāfa within Sorani and across Western Iranian languages calls for a morphomic approach, which can be formally described using a constructional approach to grammar. The study focuses on the following questions: What type of head does the izāfa mark? What is the function of this marker? What are the constraints on its distribution? What are the syntactic and morphological rules governing its distribution

Variance Analysis of Randomized Consensus in Switching Directed Networks

In this paper, we study the asymptotic properties of distributed consensus algorithms over switching directed random networks. More specifically, we focus on consensus algorithms over independent and identically distributed, directed Erdos-Renyi random graphs, where each agent can communicate with any other agent with some exogenously specified probability $p$. While it is well-known that consensus algorithms over Erdos-Renyi random networks result in an asymptotic agreement over the network, an analytical characterization of the distribution of the asymptotic consensus value is still an open question. In this paper, we provide closed-form expressions for the mean and variance of the asymptotic random consensus value, in terms of the size of the network and the probability of communication $p$. We also provide numerical simulations that illustrate our results.Comment: 6 pages, 3 figures, submitted to American Control Conference 201

Non-Bayesian Social Learning, Second Version

We develop a dynamic model of opinion formation in social networks. Relevant information is spread throughout the network in such a way that no agent has enough data to learn a payoff-relevant parameter. Individuals engage in communication with their neighbors in order to learn from their experiences. However, instead of incorporating the views of their neighbors in a fully Bayesian manner, agents use a simple updating rule which linearly combines their personal experience and the views of their neighbors (even though the neighbors’ views may be quite inaccurate). This non-Bayesian learning rule is motivated by the formidable complexity required to fully implement Bayesian updating in networks. We show that, under mild assumptions, repeated interactions lead agents to successfully aggregate information and to learn the true underlying state of the world. This result holds in spite of the apparent naıvite of agents’ updating rule, the agents’ need for information from sources (i.e., other agents) the existence of which they may not be aware of, the possibility that the most persuasive agents in the network are precisely those least informed and with worst prior views, and the assumption that no agent can tell whether their own views or their neighbors’ views are more accurate.Social networks, learning, information aggregation

Equilibrium Phase Behavior and Mass Transport in Neutral and Oppositely Charged Polymer Assemblies

Polyelectrolyte (PE) complexation (PEC) occurs upon mixing solutions of oppositely charged ‎polyelectrolytes. This electrostatic self-assembly paradigm is also extended to layer-by-layer ‎‎(LbL) assembled polyelectrolyte multilayers (PEM). Despite the broad applications of both PEC ‎and PEM, bulk phase behavior of PEC and mass transport controlling the structure and film ‎growth rate of PEMs and their connection is poorly understood. In this doctoral work, we ‎present a combined experimental and theoretical investigation of PEC and PEM LbL assembly. ‎We first observe that polymer-specific interactions have a profound effect on both PEC and LbL ‎growth rate while salinity has a non-monotonic and a rather universal effect on LbL growth rate ‎of fully ionized polyelectrolytes when normalized by the critical salinity required to suppress ‎PEC. We next develop a free energy model of PEC by incorporating counterion association-‎dissociation, cross-chain ion pairing (IP) and protonation, treating each as a reversible reaction ‎using laws of mass action. The importance of each reaction is controlled by a corresponding ‎chemistry-dependent standard free energy input parameter that could be measured via ‎experimentation or molecular simulations. In monophasic systems, the thermodynamic model can ‎qualitatively explain the shifts in acidity and basicity observed in potentiometric titration of weak ‎PEs in the presence of salt and oppositely charged PEs in accordance with Le Châtelier’s ‎principle. We demonstrate how a competition between counterion condensation and IP can ‎explain the complex coacervation of strongly charged PEs. Binodal diagrams predicted in our ‎model are most sensitive to IP strength both for weak and strong PEs. We compare binodal ‎diagrams predicted by our model against experimental data, and find a plausible parameter set ‎that leads to agreement between them. Finally, we develop a transport modeling framework for ‎LbL assembly by variational minimization of the Rayleighian of a mixture of oppositely charged ‎PEs, simple salt and water with respect to species velocities yielding species flux laws that equate ‎the net mutual friction between components with the diffusional driving force on each species. ‎The latter includes gradients in the conventional mixing chemical potential, electrostatic potential ‎and mechanical stress (only for PEs). We also develop a constitutive equation for mixtures of PEs ‎that accounts for solvent imbibition and IP. The result is a modification of the upper-convected ‎Maxwell model. Our LbL transport model captures PE adsorption and film swelling in the ‎equilibrium limit. A dynamic coupling of elastic stress and diffusion is applied in a different ‎context to an electroneutral system involving drug release from polymer tablets, capturing ‎Fickian, anomalous and case II modes of drug transport that arise naturally from the model. In ‎addition to LbL, the transport framework proposed in this work can be applied to any system of ‎charged and neutral components.‎PHDChemical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/143922/1/salehi_1.pd

Firm size, audit regulation and fraud detection

Revizor je odgovoren za preprečevanje, odkrivanje in poročanje o goljufijah. Pri revidiranju so najspornejši nezakoniti akti in napake. Ti področji sta tudi najpogostejši predmet razprave med revizorji, politiki, mediji, zakonodajalci in javnostjo (Gaz in dr. 1997). S predhodno raziskavo je bila ugotovljena pozitivna povezanost med kakovostjo revizije ter velikostjo revizorskega podjetja. Medtem ko so nekatere študije kot nadomestilo za kakovost revidiranja uporabile revizijske stroške, so druge študije uporabile bolj neposredna merila, kot so rezultati poročil o nadzoru kakovosti. Vendar so slednje študije uporabljale vzorce, ki so močno geografsko omejeni ali pa so omejeni v smislu vrste naročnika. To še ni vse. Večina raziskav o povezanosti med velikostjo in kakovostjo se je tudi osredotočila na dokaj velika pooblaščena revizijska (CPA) podjetja. Zadnja leta se je veliko razpravljalo o naravi revizijske prakse (Salehi 2007). Revizorji so odgovorni tudi za zagotavljanje točnosti in natančnosti izjav, ki jih pripravijo managerji