The Stokes-Einstein-Sutherland Equation at the Nanoscale Revisited.

The Stokes-Einstein-Sutherland (SES) equation is at the foundation of statistical physics, relating a particle's diffusion coefficient and size with the fluid viscosity, temperature, and the boundary condition for the particle-solvent interface. It is assumed that it relies on the separation of scales between the particle and the solvent, hence it is expected to break down for diffusive transport on the molecular scale. This assumption is however challenged by a number of experimental studies showing a remarkably small, if any, violation, while simulations systematically report the opposite.

Green room temperature synthesis of silver-gold alloy nanoparticles.

Metallic alloy nanoparticles (NPs) exhibit interesting optical, electrical and catalytic properties, dependent on their size, shape and composition. In particular, silver-gold alloy NPs are widely applied as model systems to better understand the syntheses and formation (kinetics) of alloy NPs, as the two elements are fully miscible. Our study targets product design environmentally friendly synthesis conditions.

Classification and characterization of multimodal nanoparticle size distributions by size-exclusion chromatography.

Size-exclusion chromatography (SEC) is a well-known, versatile and scalable technique for the separation of molecules according to their hydrodynamic size in solution as well as for the determination of molecular weight distributions of polymers. In this paper we demonstrate and generalize the applicability of SEC to the classification and characterization of multimodal distributions of nanoparticles over a broad size range. After calibration with gold standards from 5 nm to 80 nm, the calibration curve is used to determine the particle size distributions (PSDs) of the standards which are in agreement with comprehensive nanoparticle size analysis by analytical ultracentrifugation.

Multidimensional characterization of noble metal alloy nanoparticles by multiwavelength analytical ultracentrifugation.

In this study, we introduce a method for the simultaneous retrieval of two-dimensional size-composition distributions of noble metal Ag-Au alloy nanoparticles utilizing an analytical ultracentrifuge equipped with a multiwavelength extinction detector (MWL-AUC). MWL-AUC is used to measure coupled optical and sedimentation properties of the particles. The optical response of the nanoparticles is calculated using Mie's theory, where the particles' complex refractive index is corrected due to the effect of reduced mean free path of electrons.

Determination of specific and non-specific protein-protein interactions for beta-lactoglobulin by analytical ultracentrifugation and membrane osmometry experiments.

Protein-protein interactions are essential for the understanding of biological processes. Specific protein aggregation is an important aspect for many biological systems. In particular, electrostatic interactions play the key role for protein-protein interactions, as many amino acids have pH-dependent charge states.

Versatile strategy for homogeneous drying patterns of dispersed particles.

After spilling coffee, a tell-tale stain is left by the drying droplet. This universal phenomenon, known as the coffee ring effect, is observed independent of the dispersed material. However, for many technological processes such as coating techniques and ink-jet printing a uniform particle deposition is required and the coffee ring effect is a major drawback.

Effect of protein adsorption on the dissolution kinetics of silica nanoparticles.

Nanoparticulate systems in the presence of proteins are highly relevant for various biomedical applications such as photo-thermal therapy and targeted drug delivery. These involve a complex interplay between the charge state of nanoparticles and protein, the resulting protein conformation, adsorption equilibrium and adsorption kinetics, as well as particle dissolution. SiO is a common constituent of bioactive glasses used in biomedical applications.

Hydrodynamic simulations of sedimenting dilute particle suspensions under repulsive DLVO interactions.

We present guidelines to estimate the effect of electrostatic repulsion in sedimenting dilute particle suspensions. Our results are based on combined Langevin dynamics and lattice Boltzmann simulations for a range of particle radii, Debye lengths and particle concentrations. They show a simple relationship between the slope of the concentration-dependent sedimentation velocity and the range of the electrostatic repulsion normalized by the average particle-particle distance.

Determination of the yield, mass and structure of silver patches on colloidal silica using multiwavelength analytical ultracentrifugation.

Anisotropic nanoparticles offer considerable promise for applications but also present significant challenges in terms of their characterization. Recent developments in the electroless deposition of silver patches directly onto colloidal silica particles have opened up a simple and scalable synthesis method for patchy particles with tunable optical properties. Due to the reliance on patch nucleation and growth, however, the resulting coatings are distributed in coverage and thickness and some core particles remain uncoated.

Structure and adsorption behavior of high hydrostatic pressure-treated β-lactoglobulin.

Hypothesis: High hydrostatic pressure treatment causes structural changes in interfacial-active β-lactoglobulin (β-lg). We hypothesized that the pressure-induced structural changes affect the intra- and intermolecular interactions which determine the interfacial activity of β-lg. The conducted experimental and numerical investigations could contribute to the mechanistic understanding of the adsorption behavior of proteins in food-related emulsions.

Probing sedimentation non-ideality of particulate systems using analytical centrifugation.

Analytical centrifugation is a versatile technique for the quantitative characterization of colloidal systems including colloidal stability. The recent developments in data acquisition and evaluation allow the accurate determination of particle size, shape anisotropy and particle density. High precision analytical centrifugation is in particular suited for the study of particle interactions and concentration-dependent sedimentation coefficients.

Probing particle heteroaggregation using analytical centrifugation.

The controlled aggregation of colloidal particles is not only a widespread natural phenomenon but also serves as a tool to design complex building blocks with tailored shape and functionalities. However, the quantitative characterization of such heteroaggregation processes remains challenging. Here, we demonstrate the use of analytical centrifugation to characterize the heteroaggregation of silica particles and soft microgels bearing similar surface charges.

Measurement of length distribution of beta-lactoglobulin fibrils by multiwavelength analytical ultracentrifugation.

The whey protein beta-lactoglobulin is the building block of amyloid fibrils which exhibit a great potential in various applications. These include stabilization of gels or emulsions. During biotechnological processing, high shear forces lead to fragmentation of fibrils and therefore to smaller fibril lengths.

A Comprehensive Brownian Dynamics Approach for the Determination of Non-ideality Parameters from Analytical Ultracentrifugation.

Brownian dynamics (BD) has been applied as a comprehensive tool to model sedimentation and diffusion of nanoparticles in analytical ultracentrifugation (AUC) experiments. In this article, we extend the BD algorithm by considering space-dependent diffusion and solvent compressibility. With this, the changes in the sedimentation and diffusion coefficient from altered solvent properties at increased pressures are accurately taken into account.

The relationship between negative symptoms and cognitive functioning in patients at clinical high risk for psychosis.

Negative symptoms and neurocognitive performance have been reported to be negatively associated in patients with emerging psychosis. However, most previous studies focused on patients with frank psychosis and did not differentiate between subdomains of negative symptoms. Hence, we aimed to elucidate the specific relationship between negative symptoms and cognitive functioning in patients at clinical high risk (CHR) for psychosis.

The Frankfurt Complaint Questionnaire for self-assessment of basic symptoms in the early detection of psychosis-Factor structure, reliability, and predictive validity.

Objectives: Patients with schizophrenia often experience subtle disturbances in several domains of information processing-so-called basic symptoms (BS). BS are already present before onset of frank psychosis and can be assessed by interviews but also by the self-administered Frankfurt Complaint Questionnaire (FCQ). We investigated the factor structure, reliability, and predictive validity for transition to psychosis of the FCQ, comparing previously proposed factor solutions containing 1, 2, 4, and 10 factors.

Brownian dynamics simulations of analytical ultracentrifugation experiments exhibiting hydrodynamic and thermodynamic non-ideality.

Hydrodynamic and thermodynamic non-ideality are important phenomena when studying concentrated and interacting systems in analytical ultracentrifugation (AUC). Here we present an extended Brownian Dynamics (BD) based algorithm which incorporates hydrodynamic and thermodynamic non-ideality. It can serve as an independent and versatile approach for the theoretical description of interparticulate interactions in AUC, as it allows tracking the trajectory of individual particles.

Prediction of psychosis using neural oscillations and machine learning in neuroleptic-naïve at-risk patients.

Objectives: This study investigates whether abnormal neural oscillations, which have been shown to precede the onset of frank psychosis, could be used towards the individualised prediction of psychosis in clinical high-risk patients.

Methods: We assessed the individualised prediction of psychosis by detecting specific patterns of beta and gamma oscillations using machine-learning algorithms. Prediction models were trained and tested on 53 neuroleptic-naïve patients with a clinical high-risk for psychosis.

Correlations between self-rating and observer-rating of psychopathology in at-risk mental state and first-episode psychosis patients: influence of disease stage and gender.

Aim: Research findings on the correlations between self-rating and observer-rating of schizophrenic psychopathology are inconsistent and have rarely considered first-episode psychosis (FEP) and at-risk mental state (ARMS) for psychosis patients. This study investigates these correlations in ARMS and FEP patients and how they are moderated by disease stage and gender.

Methods: In the Basel Früherkennung von Psychosen (FePsy) study, positive and negative psychotic and affective symptoms were rated in 126 ARMS and 94 FEP patients using two observer- and three self-rating scales.

Early detection of psychosis: helpful or stigmatizing experience? A qualitative study.

Aim: Despite the large scientific debate concerning potential stigmatizing effects of identifying an individual as being in an at-risk mental state (ARMS) for psychosis, studies investigating this topic from the subjective perspective of patients are rare. This study assesses whether ARMS individuals experience stigmatization and to what extent being informed about the ARMS is experienced as helpful or harmful.

Methods: Eleven ARMS individuals, currently participating in the follow-up assessments of the prospective Basel Früherkennung von Psychosen (FePsy; English: Early Detection of Psychosis) study, were interviewed in detail using a semistructured qualitative interview developed for this purpose.

[The Basel Interview for Psychosis (BIP): structure, reliability and validity].

Background: Although several instruments have been developed to identify patients with an at-risk mental state (ARMS) for psychosis and first episode of psychosis (FEP), up to now there were no instruments for a detailed assessment of risk factors and indicators of emerging psychosis and the temporal development of psychiatric symptoms over the whole life span in these patients. We therefore developed the Basle Interview for Psychosis (BIP). The aim of this study is to describe the development of the BIP and to report about its psychometric properties.

Sex differences in cognitive functioning in at-risk mental state for psychosis, first episode psychosis and healthy control subjects.

Background: Several sex differences in schizophrenia have been reported including differences in cognitive functioning. Studies with schizophrenia patients and healthy controls (HC) indicate that the sex advantage for women in verbal domains is also present in schizophrenia patients. However, findings have been inconsistent.