NanoPASS: an easy-to-use user interface for nanoparticle dosimetry with the 3DSDD model.

Nanoparticles exhibit a specific diffusion and sedimentation behavior under cell culture conditions as used in nantoxicological in vitro testing. How a particular particle suspension behaves depends on the particular physicochemical characteristics of the particles and the cell culture system. Only a fraction of the nanoparticles applied to a cell culture will thus reach the cells within a given time frame.

In vitro nanoparticle dosimetry for adherent growing cell monolayers covering bottom and lateral walls.

Background: Even though a continuously high number of in vitro studies on nanoparticles are being published, the issue of correct dose matter is often not sufficiently taken into account. Due to their size, the diffusion of nanoparticles is slower, as compared to soluble chemicals, and they sediment slowly. Therefore, the administered dose of particles in in vitro experiments is not necessarily the same (effective) dose that comes into contact with the cellular system.

Electrically Tunable Dye Emission via Microcavity Integrated PDMS Gel Actuator.

Electrically tunable microcavities are essential elements for tunable laser sources indispensable for modern telecommunication and spectroscopy. However, most device concepts suffer from extensive lithography or etching for membrane processing. Here, we present an electrically and continuously tunable, multi-half-wavelength microcavity with a quality factor > 1000 as an easy-to-fabricate platform with potential use for vertical-cavity surface-emitting lasers.

Dynamic association of calcium channel subunits at the cellular membrane.

High voltage gated calcium channels (VGCCs) are composed of at least three subunits, one pore forming [Formula: see text]-subunit, an intracellular [Formula: see text]-variant, and a mostly extracellular [Formula: see text]-variant. Interactions between these subunits determine the kinetic properties of VGCCs. It is unclear whether these interactions are stable over time or rather transient.

Integrated Microfluidic Membrane Transistor Utilizing Chemical Information for On-Chip Flow Control.

Microfluidics is a great enabling technology for biology, biotechnology, chemistry and general life sciences. Despite many promising predictions of its progress, microfluidics has not reached its full potential yet. To unleash this potential, we propose the use of intrinsically active hydrogels, which work as sensors and actuators at the same time, in microfluidic channel networks.

The interaction of protein-coated bionanoparticles and surface receptors reevaluated: how important is the number of bonds?

Specifically designed bionanoparticles with a function-oriented protein-coating layer interact with self-prepared receptor surfaces as the counterpart. Based on surface plasmon resonance biosensing experiments, a model framework is validated to estimate the number of bonds formed between these bionanoparticles and the receptor surface based on multivalent interactions. Our multi-site kinetic model is able to analyze the adsorption rate constants and the number of bonds from experimental data of natural and synthetic bionanoparticles.

Binding kinetics and multi-bond: Finding correlations by synthesizing interactions between ligand-coated bionanoparticles and receptor surfaces.

The number of bonds formed between one single bionanoparticle and many surface receptors is an important subject to be studied but is seldom quantitatively investigated. A new evaluation of the correlation between binding kinetics and number of bonds is presented by varying ligand density and receptor density. An experimental system was developed using measurements with surface plasmon resonance spectroscopy.

Surface dynamics of voltage-gated ion channels.

Neurons encode information in fast changes of the membrane potential, and thus electrical membrane properties are critically important for the integration and processing of synaptic inputs by a neuron. These electrical properties are largely determined by ion channels embedded in the membrane. The distribution of most ion channels in the membrane is not spatially uniform: they undergo activity-driven changes in the range of minutes to days.

Mobility of calcium channels in the presynaptic membrane.

Unravelling principles underlying neurotransmitter release are key to understand neural signaling. Here, we describe how surface mobility of voltage-dependent calcium channels (VDCCs) modulates release probabilities (P(r)) of synaptic vesicles (SVs). Coupling distances of <10 to >100 nm have been reported for SVs and VDCCs in different synapses.

Quantifying resolution limiting factors in subtomogram averaged cryo-electron tomography using simulations.

Cryo-electron tomography (CET) is the only available technique capable of characterizing the structure of biological macromolecules in conditions close to the native state. With the advent of subtomogram averaging, as a post-processing step to CET, resolutions in the (sub-) nanometer range have become within reach. In addition to advances in instrumentation and experiments, the reconstruction scheme has improved by inclusion of more accurate contrast transfer function (CTF) correction methods, better defocus estimation, and better alignments of the tilt-series and subtomograms.

Spinal cord compression: an unusual presentation of hepatocellular carcinoma.

Hepatocellular carcinoma is the 5(th) most common cancer in men and the 2(nd) common cause of death from cancer worldwide. The tumour commonly metastasizes to the lungs, regional lymph nodes and bone. Spinal cord compression secondary to metastatic disease as a first presentation is uncommon.

Nonvasoconstrictive hemoglobin particles as oxygen carriers.

Artificial oxygen carriers, favorably hemoglobin-based oxygen carriers (HBOCs), are being investigated intensively during the last 30 years with the aim to develop a universal blood substitute. However, serious side effects mainly caused by vasoconstriction triggered by nitric oxide (NO) scavenging due to penetration of nanosized HBOCs through the endothelial gaps of the capillary walls and/or oxygen oversupply in the precapillary arterioles due to their low oxygen affinity led to failure of clinical trials and FDA disapproval. To avoid these effects, HBOCs with a size between 100 and 1000 nm and high oxygen affinity are needed.

Fluidic microchemomechanical integrated circuits processing chemical information.

Lab-on-a-chip (LOC) technology has blossomed into a major new technology fundamentally influencing the sciences of life and nature. From a systemic point of view however, microfluidics is still in its infancy. Here, we present the concept of a microfluidic central processing unit (CPU) which shows remarkable similarities to early electronic Von Neumann microprocessors.

Perforation of the sigmoid colon due to intradiscal spacer dislocation.

A case of late dislocation of a disc spacer L5/S1 with perforation of the sigmoid colon and transanal passage 4 years after implantation is reported. The objective is to describe an uncommon complication of anterior endoscopic spondylodesis L5/S1. To our knowledge, this is the first report on this rare complication.

Laser Doppler field sensor for high resolution flow velocity imaging without camera.

In this paper we present a laser sensor for highly spatially resolved flow imaging without using a camera. The sensor is an extension of the principle of laser Doppler anemometry (LDA). Instead of a parallel fringe system, diverging and converging fringes are employed.

Nanodroplet cluster formation in ionic liquid microemulsions.

A common ionic liquid (IL), 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF(4)), is used as polar solvent to induce the formation of a reverse bmimBF(4)-in-toluene IL microemulsion with the aid of the nonionic surfactant Triton X-100. The swelling process of the microemulsion droplets by increasing bmimBF(4) content is detected by dynamic light scattering (DLS), conductivity, UV/Vis spectroscopy, and freeze-fracture transmission electron microscopy (FF-TEM). The results show that the microemulsion droplets initially formed are enlarged by the addition of bmimBF(4).

Decrease of droplet size of the reverse microemulsion 1-butyl-3-methylimidazolium tetrafluoroborate/Triton X-100/cyclohexane by addition of water.

In the present contribution, results concerning the role of small amounts of water in the 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4)-in-cyclohexane ionic liquid (IL) reverse microemulsions are reported. Dynamic light scattering (DLS) revealed that the size of microemulsion droplets decreased remarkably with increasing water content although water is often used as a polar component to swell reverse microemulsions. It was thus deduced that the number of microemulsion droplets was increased which was confirmed by conductivity measurements.

Group 13 decamethylmetallocenium cations.

Salts containing the decamethylmetallocenium cations, [(C(5)Me(5))(2)M](+) (or Cp*(2)M(+)) of the group 13 "metals" B, Al and Ga have been prepared using a variety of synthetic routes. Precursor molecules of the type Cp*(2)MX (X=Cl, Br, Me) exhibit structural features that vary significantly depending on the size and electronegativity of the central atom. While salt metathesis, halide abstraction and methanide abstraction methods represent viable routes for the preparation of salts of Cp*(2)B(+) and Cp*(2)Al(+), acidolysis of a Cp* group from Cp*(3)Ga is the most reliable method for the synthesis of the analogous gallium cation.

Recent advances in electron tomography: TEM and HAADF-STEM tomography for materials science and semiconductor applications.

Electron tomography is a well-established technique for three-dimensional structure determination of (almost) amorphous specimens in life sciences applications. With the recent advances in nanotechnology and the semiconductor industry, there is also an increasing need for high-resolution three-dimensional (3D) structural information in physical sciences. In this article, we evaluate the capabilities and limitations of transmission electron microscopy (TEM) and high-angle-annular-dark-field scanning transmission electron microscopy (HAADF-STEM) tomography for the 3D structural characterization of partially crystalline to highly crystalline materials.

Coarsening of axial segregation patterns of slurries in a horizontally rotating drum.

Segregation structures of granular mixtures in rotating drums represent classical examples of pattern formation in granular material. We investigate the coarsening of axial segregation patterns of slurries in a long horizontally rotating cylinder. The dynamics and the three-dimensional geometry of the segregation structures are analyzed with optical methods and nuclear magnetic resonance imaging.

Size and distribution prediction for nanoparticles produced by microemulsion precipitation: A Monte Carlo simulation study.

A Monte Carlo simulation approach for BaSO(4) nanoparticle precipitation in microemulsions has been applied to a semi-batch reactor experiment. The simulation includes two technical process parameters, the feed rate and the initial volume ratio of the two reactants. A set of experiments with different initial reactant concentrations of BaCl(2) and K(2)SO(4) showed a significant change in the particle size.

Hollow polymer shells from biological templates: fabrication and potential applications.

Three-dimensional ultrathin polymer shells have been produced by a combination of step-by-step adsorption of polyelectrolytes on glutaraldehyde-treated human erythrocytes and subsequent solubilization of the cytoplasmatic constituents by means of a deproteinizing agent. The obtained hollow films preserve both the size and shape of the templating cells. This opens a pathway for the fabrication of polymeric capsules within a wide range of size and shape by using various biological templates.

Polyelectrolyte complexes and layer-by-layer capsules from chitosan/chitosan sulfate.

Polyelectrolyte complex formation of chitosans of varying average molecular weight and degree of acetylation with chitosan sulfate or poly(styrene sulfonate) was studied by static light scattering in dilute solution at various ionic strengths. Unlike the molecular weight, the degree of acetylation was found to have a significant effect on the resultant structural densities of the complexes. The same system was applied to the preparation of micrometer-sized hollow shells by means of a layer-by-layer technique (in total eight layers).