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This study provides a systematic comparative analysis of seven common cross-national measures of state capacity by focusing on three measurement issues: convergent validity, interchangeability, and case-specific disagreement. The author finds that the convergent validity of the measures is high, but the interchangeability of the measures is low. This means that even highly correlated measures of state capacity can lead to completely different statistical inferences. The cause of this puzzling finding lies in strikingly large disagreements on some of the country scores. The author shows that these disagreements depend on two factors: differences in underlying components and the level of state capacity. Considering the findings of this study, users of measures of state capacity must not assume that any highly correlated indicator is appropriate. They should instead look at what the indicators actually measure and ensure that a given definition of state capacity matches the chosen indicator.

By comparing and analysing four cross-national measures of democracy, this article provides novel information regarding the statistical properties, convergence, and interchangeability of some of the most frequently used measures of democracy. The author points out limitations related to the statistical properties of these measures and finds that even if measures of democracy are highly convergent, their interchangeability is weak. This means that the choice of the measure of democracy has considerable consequences for the conclusions of a given study. Especially so in studies covering the last few decades, because the author finds that in general the interchangeability of democracy measures has decreased since the 1980s. In choosing one measure over another, scholars should be aware of the limitations identified in this article. To overcome problems related to weak interchangeability, if a single measure cannot be credibly chosen on theoretical grounds, the author recommends users of the measures to validate their findings with multiple measures of democracy.

In recent decades, there has been an institutional shift in the literature on authoritarian regimes, with scholars investigating the role of political institutions, such as elections and political parties, in shaping regime stability and economic performance. However, scant attention has been devoted to the effect of political institutions on policy outcomes, and more specifically, on income inequality. This paper adds to this debate and sheds light on the role of formal and informal institutions, on the one hand, and state capacity, on the other, in influencing levels of income inequality in autocracies. We argue that, while the presence of elections and multiparty competition creates more favourable conditions for the adoption of redistributive policies, state capacity increases the likelihood of successfully implemented policy decisions aimed at reducing the level of inequality. Our empirical analysis rests on a time-series cross-sectional dataset, which includes around 100 countries from 1972 to 2014. The findings indicate that both political institutions and a higher level of state capacity lead to lower levels of income inequality in authoritarian contexts.

We prove that it is consistent with ZFC that every unital endomorphism of the Calkin algebra $\mathcal{Q}(H)$ is unitarily equivalent to an endomorphism of $\mathcal{Q}(H)$ which is liftable to a unital endomorphism of $\mathcal{B}(H)$. We use this result to classify all unital endomorphisms of $\mathcal{Q}(H)$ up to unitary equivalence by the Fredholm index of the image of the unilateral shift. As a further application, we show that it is consistent with ZFC that the class of $\mathrm{C}^\ast$-algebras that embed into $\mathcal{Q}(H)$ is not closed under tensor product nor countable inductive limit., Comment: 23 pages. Final journal version, with minor changes with respect of the first version

In 2016, an update of the 2009 recommendations for the evaluation of left ventricular (LV) diastolic function (DF) was released by the American Society of Echocardiography and the European Association of Cardiovascular Imaging. The aims of this study were to assess the concordance between the 2016 and 2009 recommendations and to test the impact of the consideration of "myocardial disease" recommended in the 2016 update on the evaluation of diastolic dysfunction (DD) and LV filling pressures in patients with normal and reduced LV ejection fractions referred to a general echocardiography laboratory.A total of 1,508 outpatients referred to an echocardiography laboratory during a predefined 5-month period were prospectively enrolled. All patients underwent targeted clinical history and Doppler echocardiographic examination. DD and LV filling pressures were assessed according to 2009 and 2016 recommendations. Concordance was calculated using the κ coefficient and overall proportion of agreement.Overall proportion of agreement between the two recommendations was 64.7% (κ = 0.43). Comparing the 2009 and 2016 recommendations, 47.5% and 36.1% patients, respectively, had DD (P .0001), and 22.7% and 12.6% had elevated LV filling pressures (P .0001). This difference remained significant in the setting of patients with normal LV ejection fractions (21.6% vs 10.7%, P .0001). In the application of the 2016 recommendations, whether or not the presence of "myocardial disease" was considered, the prevalence of indeterminate diastolic function was, respectively, 7.3% versus 13.7%, while patients in whom the DD grade could not be determined were 8.1% versus 14.4% (P .0001 for all).Considering the presence of myocardial disease when applying the 2016 recommendations resulted in a lower prevalence of inconclusive diagnosis.

We prove that, under Martin’s axiom, every ${\mathrm{C}}^\ast $-algebra of density character less than continuum embeds into the Calkin algebra. Furthermore, we show that it is consistent with Zermelo-Fraenkel set theory plus the axiom of choice, ZFC, that there is a $\mathrm{C}^\ast $-algebra of density character less than continuum that does not embed into the Calkin algebra.

We expect effective state institutions to matter in a country's ability to respond to crises. Yet notably in the first year of the COVID-19 pandemic, what has stood out in simple global snapshots is that wealthier countries with stronger institutions have had the highest numbers of cases and fatalities on average, while many poorer countries with weaker institutions have been praised for more effective pandemic responses. What explains this seeming puzzle?

A counterexample to Naimark's problem is a C ⁎ -algebra that is not isomorphic to the algebra of compact operators on some Hilbert space, yet still has only one irreducible representation up to unitary equivalence. It is well-known that such algebras must be nonseparable, and in 2004 Akemann and Weaver used the diamond principle (a set theoretic axiom independent from ZFC ) to give the first counterexamples. For any such counterexample A, the unitary group U ( A ) acts transitively on the pure states, which are the extreme points of the state space S ( A ) . It is conceivable that this implies (as happens for finite-dimensional simplexes) that the action of U ( A ) on S ( A ) has at most one fixed point, i.e. A has at most one trace. We give a strong negative answer here assuming diamond. In particular, we adapt the Akemann–Weaver construction to show that the trace space of a counterexample to Naimark's problem can be affinely homeomorphic to any metrizable Choquet simplex, and can also be nonseparable.

Context Vitamin D deficiency patients have an increased cardiovascular (CV) morbidity and mortality. Carotid intima-media thickness (IMT) and carotid plaques are markers of subclinical atherosclerosis and predictors of CV events. Objective To perform a meta-analysis of studies evaluating the impact of Vitamin D deficiency on common carotid artery IMT (CCA-IMT) and on the prevalence of carotid plaques. Data Sources Studies were systematically searched in the PubMed, Web of Science, Scopus and EMBASE databases. Results Twenty-one studies (3,777 Vitamin D deficiency patients and 4,792 controls) with data on CCA-IMT and 6 studies (1,889 Vitamin D deficiency patients and 2,883 controls) on the prevalence of carotid plaques were included. Compared to controls, Vitamin D deficiency patients showed a significantly higher CCA-IMT (mean difference [MD]: 0.043 mm; 95%CI: 0.030, 0.056; P

Despite a few decades of research on the topic, the economic and social impact of microfinance remains open to question. While in some cases microfinance has had the desired results, in many others it has not lived up to the expectations of the development community. In addition, macro-level effects of microfinance have not been analyzed thoroughly and there are only a limited number of empirical cross-national studies on the relationship between microfinance and development. Through a quantitative macro-level approach on the topic, our research investigates the role of microfinance in economic and social development in sub-Saharan Africa. Employing a sample of nearly 40 sub-Saharan African countries from 1999 to 2014, we find robust empirical evidence for a positive, albeit relatively weak, overall effect of microfinance on GDP/capita and human capital.

Because of a mistake in the proof of [10, Theorem A - part 1] , the main statements of [10] ( [10, Theorem 1 - part 1] and [10, Theorem 2] ) are not proved in full generality. We provide an alternative proof to such statements.

Patients with short bowel syndrome (SBS) on long-term home parenteral nutrition (HPN) chronically receive high fluid volumes directly into the right atrium (RA) through the superior vena cava. We retrospectively evaluated cardiac function measured by routine transthoracic echocardiography (TTE) in a population of 26 SBS patients on long-term HPN and compared their data on echocardiograph-derived right heart structure and function, with those of a control group of 26 patients also bearing a central venous catheter (CVC) for other reasons. Results showed that body weight and BMI were significantly higher in the control group. The echocardiographic estimate of RA pressure was higher in HPN patients than in controls (p = 0.01). An increased estimate of RA pressure indicates the need to consider TTE in the follow-up of long-term HPN patients to detect functional impairment early.

It is common knowledge in the set theory community that there exists a duality relating the commutative $C^*$-algebras with the family of $B$-names for complex numbers in a boolean valued model for set theory $V^B$. Several aspects of this correlation have been considered in works of the late $1970$'s and early $1980$'s, for example by Takeuti, and by Jech. Generalizing Jech's results, we extend this duality so as to be able to describe the family of boolean names for elements of any given Polish space $Y$ (such as the complex numbers) in a boolean valued model for set theory $V^B$ as a space $C^+(X,Y)$ consisting of functions $f$ whose domain $X$ is the Stone space of $B$, and whose range is contained in $Y$ modulo a meager set. We also outline how this duality can be combined with generic absoluteness results in order to analyze, by means of forcing arguments, the theory of $C^+(X,Y)$., 27 pages

BACKGROUND: Brown adipose tissue (BAT) was considered essentially nonexistent in adults until recent evidence obtained using 18-fluorodeoxyglucose (18-FDG) positron emission tomography/computed tomography. It seems to play a role in whole body metabolism, but it has not been evaluated in underweight conditions, such as in young females with constitutional leanness (CL) or anorexia nervosa (AN). SUBJECTS AND METHODS: Thirty-eight subjects were evaluated from October 2011 to March 2012 : 7 CL (21.7 ± 3.6 y, body mass index [BMI] 16.2 ± 1.0 kg/m(2)), 7 AN (23.4 ± 4.5 y, BMI 15.5 ± 0.8), 3 of the 7 AN after stable refeeding (R-AN, 21.3 ± 1.5 y, BMI 18.8 ± 1.1), and 24 normal weight (NW) women (25.6 ± 3.9 y, BMI 22.2 ± 1.5). Fasting resting metabolic rate and respiratory quotient were measured by indirect calorimetry, body composition by bioimpedentiometry (only in CL, AN, and refed AN), and BAT activity by 18-FDG positron emission tomography/computed tomography scan, all in standardized conditions. RESULTS: All CL (100%), none of the AN and refed AN (0%), and 3 of the 24 NW (12%) subjects showed FDG uptake. Average FDG maximum standardized uptake value was 11.4 + 6.7 g/mL in CL and 5.5 ± 1.2 g/mL (min 3.7, max 8.3) in the 3 NW subjects. In CL, the maximum standardized uptake value was directly correlated to resting metabolic rate, corrected for fat-free mass, and inversely correlated with respiratory quotient. CONCLUSION: BAT activity has been shown in CL in resting thermoneutral conditions and may exert a role against adipose tissue deposition.

Let $A$ be a non-commutative, non-unital $\mathrm{C}^\ast$-algebra. Given a set of commuting positive elements in the corona algebra $Q(A)$, we study some obstructions to the existence of a commutative lifting of such set to the multiplier algebra $M(A)$. Our focus are the obstructions caused by the size of the collection we want to lift. It is known that no obstacles show up when lifting a countable family of commuting projections, or of pairwise orthogonal positive elements. However, this is not the case for larger collections. We prove in fact that for every primitive, non-unital, $\sigma$-unital $\mathrm{C}^\ast$-algebra $A$, there exists an uncountable set of pairwise orthogonal positive elements in $Q(A)$ such that no uncountable subset of it can be lifted to a set of commuting elements of $M(A)$. Moreover, the positive elements in $Q(A)$ can be chosen to be projections if $A$ has real rank zero., Comment: 11 pages

Sulfate-terminated latex particles were investigated in the presence of poly(diallyldimethyl ammonium chloride) (PDADMAC) at pH 4.0 in aqueous KCl electrolyte solutions by dynamic light scattering and electrophoresis, in particular, at high ionic strengths. The polyelectrolyte adsorbs to the latex particles quantitatively until the adsorption plateau is reached. The adsorbed amount at this plateau and the corresponding layer thickness increase with increasing ionic strength. The resulting layers have a thickness of several nanometers. Colloidal stability is qualitatively consistent with electrostatic double layer forces, especially since the system can be fully destabilized at high ionic strengths even at high polyelectrolyte doses. Additional attractive forces due to lateral charge heterogeneities seem to contribute to the destabilization of the system, even for the adsorbed layers in the saturated state. However, this layer does not provide any additional stabilization mechanism due to steric repulsion forces, since the adsorbed polyelectrolyte layers are thin and laterally heterogeneous even in their saturated state.

An adsorbed layer of a cationic polyelectrolyte, poly(diallyldimethyl-ammonium) chloride (PDADMAC) on negatively charged colloidal latex particles was investigated by small-angle neutron scattering (SANS) and dynamic light scattering (DLS). SANS gives a layer thickness of 8 +/- 1 A and a polymer volume fraction of 0.31 +/- 0.05 within the film. DLS gives a somewhat larger thickness of 18 +/- 2 A, and the discrepancy is likely due to the inhomogeneous nature of the layer and the existence of polymer tails or loops protruding into solution. These results show that a highly charged polyelectrolyte adsorbs on an oppositely charged colloidal particle in a flat configuration due to the attractive forces acting between the polyelectrolyte and the substrate.

Aims The determinants of systolic function in the performing heart are not completely understood. Aim of the study was to assess the contributors of left ventricular (LV) strain components, using 3D speckle tracking echocardiography (STE) in endurance athletes. Methods and results A total of 36 top-level male endurance athletes (AT) and 36 age-matched sedentary normal controls (NC) underwent standard and real-time 3D echocardiography. Global longitudinal strain (GLS), global circumferential strain (GCS), global area strain (GAS), and global radial strain (GRS) were assessed using 3D STE. AT had significantly higher GLS (−22.1 ± 4.4 vs. −18.4 ± 3.5%; P < 0.0001), GCS (−17.9 ± 2.4 vs. −16.0 ± 3.2; P = 0.006), and GAS (−35.5 ± 6.7 vs. −30.2 ± 4.9; P < 0.0001), while GRS did not differ significantly with NC. At separate multiple linear regression analyses, heart rate emerged as independent predictor of GLS ( β = −0.37, P < 0.002), GCS ( β = −0.32, P = 0.007), GAS ( β = −0.37, P < 0.001), and GRS ( β = −0.29, P = 0.019); LV mass was independently associated with GLS ( β = 0.34, P = 0.009) and GAS ( β = 0.41, P < 0.001) but not with GCS and GRS, while diastolic blood pressure predicted GCS ( β = −0.46, P < 0.0001), GAS ( β = −0.28; P = 0.006), and GRS ( β = −0.42, P < 0.001). No independent correlation emerged for body surface area and stroke volume. By replacing LV mass with end-diastolic volume, the latter showed independent association with GCS ( β = −0.65, P = 0.028) and with GRS ( β = −0.60, P < 0.05). Conclusion AT have an increased myocardial function at rest when compared with NC, this being elicited mainly by subendocardial and mid-wall fibres. Sinus bradycardia, LV mass, and afterload are independent determinants of supernormal myocardial deformation at rest.

A model for particle detection in focused beam reflectance measurement is presented in the general case of particles of any convex shape. Shape dependent convolution relationships between measured chord length distribution (CLD), particle size distribution (PSD) and particle mass distribution (PMD) are derived and an explicit formula for the weighting characteristic length is given in terms of particle shape. Based on the derived convolution relationships, equations relating moments of the CLD, PSD and PMD are obtained. Issues related to the definition of particle size of non spherical objects and its connection to the particle sizing technique are discussed. Based on the moment relationships, particle size is defined for focused beam reflectance measurement measurements in terms of a CLD equivalent sphere. CLD and characteristic length for a thin cylinder are obtained analytically and used as simple model in order to illustrate issues in sizing particles of variable shape, General conclusions regarding the role of the weighting characteristic length on the behavior of the measured CLD are drawn.

Control of aggregation and gelation of nanoparticles is among important issues in processing of colloidal systems. Aggregation of nanoparticles to clusters with desired size and structure can be achieved in continuous processing, assuming that the colloidal stability of primary particles can be manipulated by mixing with an appropriate coagulant, while at the same time gelation of the bulk dispersion is avoided. On the other hand, gelation might be desired in order to obtain gelled domains of appropriate size, while keeping the resulting solids in suspended state. Typical industrial conditions often involve large particle concentrations and small particle sizes, where timescales of mixing, aggregation and gelation are comparable. Therefore, one needs to account for interplay of these processes in order to understand and control effects of mixing on gel formation in nanoparticle dispersions. We discuss recent developments in kinetic modeling of aggregation and gelation of nanoparticle dispersions and analyze the role of mixing of dispersion and coagulant streams in controlling gelation kinetics, with the objective of better understanding and improved design of relevant industrial processes.

We propose a general methodology for the estimation of the doublet formation rate constant (proportional to the stability ratio of primary particles) in colloidal dispersions from measurements obtained by common optical techniques, such as dynamic light scattering, static light scattering (nephelometry) or turbidimetry. In contrast to previous approaches relying on the initial slopes of the measured quantities, such as the mean hydrodynamic radius, scattered light intensity or turbidity, we introduce a transformation of the measurables to properly scaled quantities, which grow linearly in time with a slope proportional to the doublet formation rate. Analysis of systematic and random errors allows one to control the error in the estimated value of the aggregation rate. Using this approach, we measured the aggregation rate constant of colloidal polymer particles prepared by surfactant-free emulsion copolymerization of styrene and 2-hydroxyethyl methacrylate (HEMA). It was found that the stability ratio at constant ionic strength decreases with increasing dilution of the original polymer latex. This can be explained by the presence of non-reacted stabilizing species (most likely oxidized HEMA) that desorb from the particle surface upon latex dilution and thus diminish the repulsive interactions between particles. In order to check if the stability of latex particles is influenced by reversibly adsorbed species it is always necessary to perform aggregation experiments at various dilutions.

In epidemiological studies, the intake of foods rich in dietary fiber is associated with a reduced risk of developing overweight and type 2 diabetes. This work aims to identify acute strategies to regulate appetite and improve glucose control by using different pasta meals. Hence, 4 different isocaloric lunch meals, consisting of (i) refined-grain pasta (RG+T), (ii) whole-grain pasta (WG+T), (iii) lemon juice-supplemented refined-grain pasta (LRG+T), and (iv) refined-grain pasta with legumes (RG+L), were administered to 8 healthy participants in a crossover design. On the test days, participants underwent baseline measurements, including appetite sensation, blood sample, and resting energy expenditure (EE), after which the test lunch was served. Subjective appetite was assessed and a blood sample was taken each hour for 240 min, and postprandial EE was measured for 3 h. In repeated-measures analysis of covariance (ANCOVA), postprandial fullness (p = 0.001) increased and hunger (p = 0.038) decreased. WG+T had a lower EE than did both LGR+T (p = 0.02) and RG+L (p < 0.001). Likewise, meal-induced thermogenesis was lower for WG+T compared with RG+L (58 ± 81 kJ vs 248 ± 188 kJ; p < 0.05). Plasma glucose (p = 0.001) was lower for RG+T, and triacylglycerols (p = 0.02) increased for LRG+T; however, insulin, C-peptide, and ghrelin were comparable in all other meals. In conclusion, our study indicates that acute consumption of whole-grain pasta may promote fullness and reduce hunger, lowering postprandial thermogenesis, and adding lemon juice to the pasta or legumes does not appear to affect appetite. However, none of pasta meal alterations improved the postprandial metabolic profile.

Nowadays the focus on power consumption represent a very important factor regarding the reduction of power consumption with correlated costs and the environmental sustainability problems. Automatic control load based on power consumption and use cycle represents the optimal solution to costs restraint. The purpose of these systems is to modulate the power request of electricity avoiding an unorganized work of the loads, using intelligent techniques to manage them based on real time scheduling algorithms. The goal is to coordinate a set of electrical loads to optimize energy costs and consumptions based on the stipulated contract terms. The proposed algorithm use two new main notions: priority driven loads and smart scheduling loads. The priority driven loads can be turned off (stand by) according to a priority policy established by the user if the consumption exceed a defined threshold, on the contrary smart scheduling loads are scheduled in a particular way to don’t stop their Life Cycle (LC) safeguarding the devices functions or allowing the user to freely use the devices without the risk of exceeding the power threshold. The algorithm, using these two kind of notions and taking into account user requirements, manages loads activation and deactivation allowing the completion their operation cycle without exceeding the consumption threshold in an off-peak time range according to the electricity fare. This kind of logic is inspired by industrial lean manufacturing which focus is to minimize any kind of power waste optimizing the available resources.

Repulsive electrostatic double-layer forces are responsible for the stabilization of charged colloidal particles in the presence of adsorbed polyelectrolytes of opposite and high line charge densities. This mechanism is revealed by studies of electrophoretic mobility and colloidal stability performed with dynamic light scattering as a function of the polyelectrolyte dose and the ionic strength for two different types of latex particles and four different types of polyelectrolytes. The dependence of these quantities is very similar for bare charged latex particles and the same particles in the presence of the different oppositely charged polyelectrolytes. Positively charged particles in the presence of anionic polyelectrolytes behave analogously to negatively charged particles in the presence of cationic polyelectrolytes.

The skeleton is one main sites of metastasis of solid tumors, and metastatic bone disease are most common malignant disease of the bone. The diagnosis and assessment of bone metastases require integrated multimodality combined approach of different diagnostic methods, including both different radionuclides that radiological techniques such as X-rays, CT and MRI. In this scenario the nuclear medicine gives a significant contribution to the evaluation of skeletal metastases. In this article we will analyze the main approaches.

Radiolabeled cell-surface peptide receptor-binding molecules are emerging as an important class of radiopharmaceuticals. Main approach has been the use of 111In Octreotide as functional imaging to find NETs. In some tumor types, it is considered the diagnostic gold standard. This article focuses on the current status of peptide-receptor scintigraphy in different tumors, in other oncologic and non oncologic applications and on future developments in these fields.

The purpose of the present study was to investigate the physicochemical properties in aqueous media of amphiphilic hyaluronic acid (HA) derivatives obtained by reaction of HA's hydroxyl groups with octenyl succinic anhydride (OSA). The self-associative properties of the resulting octenyl succinic anhydride-modified hyaluronic acid (OSA-HA) derivatives were studied by fluorescence spectroscopy using Nile Red as fluorophore. The morphology, size and surface charge of the OSA-HA assemblies were determined by transmission electron microscopy, dynamic light scattering and by measuring their electrophoretic mobility, respectively. OSA-HA was shown to spontaneously self-associate in aqueous media into negatively charged spherical and multiphasic nanostructures with a hydrodynamic diameter between 170 and 230 nm and to solubilize hydrophobic compounds such as Nile Red. This was a good indication that OSA-HA could be used as building block for the formulation of soft nanocarriers towards the encapsulation and controlled delivery of hydrophobic active ingredients or drugs.

The thickness of adsorbed polyelectrolyte layers on oppositely charged particles can be measured by dynamic light scattering (DLS) with a precision of fractions of a nanometer. However, such data can be only reliably obtained when effects of particle aggregation are carefully eliminated by working at low particle number concentrations. In order to achieve a sufficient light scattering intensity at the same time, the size of colloidal particles must be chosen relatively large. We find that such measurements are best carried out with latex particles in the range of diameters of 150−300 nm. The precision of the measurement can be further enhanced with multiangle DLS. The thickness of adsorbed polyelectrolyte layers on oppositely charged particles is normally below 10 nm. At low ionic strengths, a typical thickness is merely 1−2 nm, while at higher ionic strengths one observes thicknesses between 6 and 9 nm. The transition between these two regimes occurs at ionic strengths 0.01−0.05 M. These observations were made with various highly charged cationic and anionic polyelectrolytes and can be considered as quite generic.

International audience; he synthesis of ligands with five symmetrically diverging binding sites is described and their assembly into large spherical structures (such as that shown here) investigated. Synthetic routes to a penta(4-pyridyl)cyclopentadienyl ligand are explored. The most successful route uses a palladium-catalysed pentapyridation of di(tert-butyl)phosphinoferrocene by using a procedure developed by Hartwig. The same method allows the synthesis of cyclopentadiene ligands substituted with 4-benzaldehydes or 4-phenylthiols. The pyridine ligands are formally five-connected nodes that may be linked by linear coordination metals to give closed spherical complexes of composition [(metal)30(ligand)12] as shown by molecular modelling. Experiment shows that the ligand complexes copper(I) and silver(I) with the expected 1:2.5 stoichiometry, and the 1H NMR spectrum of the resulting product shows the ligands to be equivalent. NMR diffusion and light-scattering measurements support the formation of a species with a hydrodynamic radius of the order of 15 Å, in agreement with the modelling studies. The resulting complex would be topologically identical to the C60 fullerene structure.

Charging of poly(acrylic acid) (PAA) in the presence of different alkali metal counterions was studied by precision potentiometric titration. The charging behavior can be described with a novel cylinder Stern model quantitatively. This model is based on the Poisson–Boltzmann equation in the cylinder geometry and a constant Stern capacitance. One finds an increasing cylinder radius with increasing mass of the alkali metal ion and a correspondingly decreasing Stern capacitance. The intrinsic ionization constants for the uncharged polymer are found to decrease with ionic strength, similarly to weak acids of low molecular mass.

An assessment of the relative magnitude of the timescales of mixing and aggregation of fully destabilized polymeric latices in stirred vessels is presented. It is demonstrated that, in industrially relevant conditions (that is, volume fractions above 10% and primary aggregate sizes below 200 nm), latices aggregate and possibly gel before complete mixing is achieved. By means of focused beam reflectance measurements, we measure on-line and in situ the size of aggregates obtained aggregating a PVDC latex at salt concentrations above the critical coagulation concentration in a stirred vessel operated in semibatch. Several experimental runs are conducted and averages of the aggregate size distribution, that is, volume and number averages, are measured at various values of the feed flowrate, feed solid volume fraction, stirring speed and final volume fraction in the vessel. It is,found that at high feeding volume fractions aggregates instantaneously aggregate and gel on entering the vessel. Resulting aggregates are then broken down to volume weighted average sizes falling in the range between 100 and 400 microns at steady state. The experimental results are interpreted in terms of a competition between the aggregation/gelation process and mixing. In particular, by evaluating the relevant characteristic times, it is found that the process is dominated by the competition between mesomixing at the location, where the latex enters the vessel and the aggregation/gelation process. Scanning electron micrographs of dry samples obtained after thermal treatment show aggregate morphologies which further support the above interpretation.

We report the application of the pulse gradient spin-echo (PGSE) NMR technique (PGSE NMR) to the analysis of large colloidal materials, specifically vesicles formed from macromolecular amphiphiles and nanoparticles. Measurements of size and size distribution were demonstrated to be comparable to those obtained through dynamic light scattering or hydrodynamic chromatography. In comparison to these more common analytical methods, the use of PGSE NMR is particularly advantageous in that, as a spectroscopic technique, it adds chemical selectivity to the study of physical dimensions. In this way, chemically different species contemporarily present in a sample may be individually studied. In addition, we demonstrate the use of PGSE NMR to probe the existence of equilibria between macroamphiphiles present in solution and those present in vesicles or on the surface of nanoparticles. This feature in particular opens exciting possibilities for the characterization of the phase behavior and of the surface adsorption phenomena of colloids.