830 research outputs found

    Modeling the effect of molecular architecture of comb polymers on the behavior of Al2O3 dispersions using charge/composition factors (CCF)

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    Erworben im Rahmen der Schweizer Nationallizenzen (www.nationallizenzen.ch)In this work, we study the effect of periodicity and PEO side-chain length in four PMAA-PEO (sodium salt) comb polymers with known molecular architecture on Al2O3 colloidal dispersions in DI water. We introduce here charge composition factors (CCF) representing charge density of the comb polymers defined as (number of charged units in a repeating unit)/(molecular weight of a repeating unit). We find, for the first time to our knowledge, that the CCF can be used along with dispersant dosage to obtain explicit functions predicting the conductivity of the dispersants in solution, the zeta potential behavior during dispersant titrations, and the isoelectric point (IEP) of the dispersions. In addition, the dosage normalized by the CCF provides a basis for comparison for the dispersants to elucidate the trends found in adsorption and potentiometric titrations. Thus, the CCF can be used as a tool for the design of improved and new comb polymer molecular architectures

    Development of ceramic based stationary phases for chromatography

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    Modeling the effect of molecular architecture of comb polymers on the behavior of Al2O3 dispersions using charge/composition factors (CCF)

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    In this work, we study the effect of periodicity and PEO side-chain length in four PMAA-PEO (sodium salt) comb polymers with known molecular architecture on Al2O3 colloidal dispersions in DI water. We introduce here charge composition factors (CCF) representing charge density of the comb polymers defined as (number of charged units in a repeating unit)/(molecular weight of a repeating unit). We find, for the first time to our knowledge, that the CCF can be used along with dispersant dosage to obtain explicit functions predicting the conductivity of the dispersants in solution, the zeta potential behavior during dispersant titrations, and the isoelectric point (IEP) of the dispersions. In addition, the dosage normalized by the CCF provides a basis for comparison for the dispersants to elucidate the trends found in adsorption and potentiometric titrations. Thus, the CCF can be used as a tool for the design of improved and new comb polymer molecular architectures

    Parallelisation and application of AD3 as a method for solving large scale combinatorial auctions

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    Auctions, and combinatorial auctions (CAs), have been successfully employed to solve coordination problems in a wide range of application domains. However, the scale of CAs that can be optimally solved is small because of the complexity of the winner determination problem (WDP), namely of finding the bids that maximise the auctioneerā€™s revenue. A way of approximating the solution of a WDP is to solve its linear programming relaxation. The recently proposed Alternate Direction Dual Decomposition algorithm (AD3) has been shown to ef- ficiently solve large-scale LP relaxations. Hence, in this paper we show how to encode the WDP so that it can be approximated by means of AD3. Moreover, we present PAR-AD3, the first parallel implementation of AD3. PAR-AD3 shows to be up to 12.4 times faster than CPLEX in a single-thread execution, and up to 23 times faster than parallel CPLEX in an 8-core architecture. Therefore PAR- AD3 becomes the algorithm of choice to solve large-scale WDP LP relaxations for hard instances. Furthermore, PAR-AD3 has potential when considering large- scale coordination problems that must be solved as optimisation problems.Research supported by MICINN projects TIN2011-28689-C02-01, TIN2013-45732-C4-4-P and TIN2012-38876-C02-01Peer reviewe

    Multi-parameter improvement method for (micro-) structural properties of high performance ceramics

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    Many pH-measurement electrodes rely on porous diaphragms to create aĀ liquid electrolyte junction between reference-electrolyte and the fluid to beĀ measured. In field applications, the diaphragm is required to meet partlyĀ contradictory improvement criteria. To minimize measurement errors and toĀ ensure durability of the measurement device, the diaphragm is supposed toĀ maximize electrolyte conductivity and reference-electrolyte outflow velocity,Ā while simultaneously minimizing reference electrolyte flow rate. The task ofĀ optimizing the overall performance of this small piece of ceramics has leadĀ to the development of a novel multi-parameter improvement scheme for itsĀ (micro-) structural design. The method encompasses the consideration ofĀ microscopic material design parameters, such as porosity, pore-tortuosityĀ and constrictivity, macroscopic material parameters such as diaphragmĀ diameter and length, as well as process parameters like internal electrodeĀ pressure or the electrolyte viscosity and specific resistivity. Comprising setsĀ of design parameters to dimensionless groups, concrete design guidelinesĀ as well as the introduction of a three-dimensional improvement spaceĀ concept are proposed. The novel design space concept allows theĀ improvement of each possible diaphragm-based measurement set-up, byĀ considering the simultaneous, dimensionless interaction of all relevantĀ design parameters

    Comparison of freeze drying and spray drying to obtain porous nanostructured granules from nanosized suspensions

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    This work studies the spray drying and freeze drying of different nanosized ceramic materials and the physicochemical characteristics of the obtained granules. Colloidal suspensions of alumina, titania, and a 87/13 mixture were studied. The influence of temperature, pressure, nozzle diameter, and solids loading on the morphology and characteristics of dried granules were evaluated. It was demonstrated that these processing parameters have practically no influence, and the only parameter determining the granules characteristics is the solids content of the suspensions, in both processes. Spray drying leads to a monomodal distribution with higher granule size, while freeze drying produces more porous granules, with a bimodal intragranular distribution. The flowability of spray-dried powder is better than that of the freeze-dried powder and suit better the requirements of a feedstock targeted to obtain coatings by plasma thermal spraying whereas freeze drying can produce high porosity, softer granule

    Escherichia coli induces apoptosis and proliferation of mammary cells

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    Mammary cell apoptosis and proliferation were assessed after injection of Escherichia coli into the left mammary quarters of six cows. Bacteriological analysis of foremilk samples revealed coliform infection in the injected quarters of four cows. Milk somatic cell counts increased in these quarters and peaked at 24 h after bacterial injection. Body temperature also increased, peaking at 12 h postinjection, The number of apoptotic cells was significantly higher in the mastitic tissue than in the uninfected control. Expression of Bax and interleukin-1 beta converting enzyme increased in the mastitic tissue at 24 h and 72 h postinfection, whereas Bcl-2 expression decreased at 24 h but did not differ significantly from the control at 72 h postinfection, Induction of matrix metalloproteinase-g, stromelysin-1 and urokinase-type plasminogen activator was also observed in the mastitic tissue. Moreover, cell proliferation increased in the infected tissue, These results demonstrate that Escherichia coli-induced mastitis promotes apoptosis and cell proliferation

    Different attachment styles correlate with mood disorders in adults with epilepsy or migraine.

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    PURPOSE: Interpersonal relationships are viewed as important contexts within which psychopathology emerges and persists or desists. Attachment theory describes the dynamics of long-term relationships between humans especially in families and lifelong friendships. The present study was aimed at investigating attachment styles in adult patients with epilepsy as compared to subjects with migraine and their potential correlates with a history of mood disorders. METHODS: A consecutive sample of 219 adult outpatients with epilepsy (117) or migraine (102) was assessed with the Attachment Style Questionnaire (ASQ). RESULTS: Patients with epilepsy and a lifetime history of mood disorders presented elevated scores for Need for approval (p<0.001) and Preoccupation with relationships (p<0.001). Age correlated with the Relationships as secondary (r=0.322; p<0.001) and Need for approval (r=0.217; p=0.019) subscales while age at onset correlated only with Relationships as secondary (r=0.225; p=0.015). Seizure-free patients presented lower scores for Need for approval (p=0.003). Patients with migraine and a lifetime history of mood disorders presented lower scores in Confidence (p=0.002) and higher scores in Discomfort with closeness (p=0.026). CONCLUSIONS: An anxious-preoccupied attachment correlated with mood disorders in epilepsy while it was an avoidant pattern in migraine. Our results bring further data on the role of psychological variables in mood disorders in epilepsy. Further studies will allow early identification of patients at risk and the development of preventive strategies

    The complex TIE between macrophages and angiogenesis

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    Macrophages are primarily known as phagocytic immune cells, but they also play a role in diverse processes, such as morphogenesis, homeostasis and regeneration. In this review, we discuss the influence of macrophages on angiogenesis, the process of new blood vessel formation from the pre-existing vasculature. Macrophages play crucial roles at each step of the angiogenic cascade, starting from new blood vessel sprouting to the remodelling of the vascular plexus and vessel maturation. Macrophages form promising targets for both pro- and anti-angiogenic treatments. However, to target macrophages, we will first need to understand the mechanisms that control the functional plasticity of macrophages during each of the steps of the angiogenic cascade. Here, we review recent insights in this topic. Special attention will be given to the TIE2-expressing macrophage (TEM), which is a subtype of highly angiogenic macrophages that is able to influence angiogenesis via the angiopoietin-TIE pathway

    The listening talker: A review of human and algorithmic context-induced modifications of speech

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    International audienceSpeech output technology is finding widespread application, including in scenarios where intelligibility might be compromised - at least for some listeners - by adverse conditions. Unlike most current algorithms, talkers continually adapt their speech patterns as a response to the immediate context of spoken communication, where the type of interlocutor and the environment are the dominant situational factors influencing speech production. Observations of talker behaviour can motivate the design of more robust speech output algorithms. Starting with a listener-oriented categorisation of possible goals for speech modification, this review article summarises the extensive set of behavioural findings related to human speech modification, identifies which factors appear to be beneficial, and goes on to examine previous computational attempts to improve intelligibility in noise. The review concludes by tabulating 46 speech modifications, many of which have yet to be perceptually or algorithmically evaluated. Consequently, the review provides a roadmap for future work in improving the robustness of speech output
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