Simultaneous Culturing of Cell Monolayers and Spheroids on a Single Microfluidic Device for Bridging the Gap between 2D and 3D Cell Assays in Drug Research

Two‐dimensional (2D) cell cultures have been the primary screening tools to predict drug impacts in vitro for decades. However, owing to the lack of tissue‐specific architecture of 2D cultures, secondary screening using three‐dimensional (3D) cell culture models is often necessary. A microfluidic approach that facilitates side‐by‐side 2D and 3D cell culturing in a single microchannel and thus combines the benefits of both set‐ups in drug screening; that is, the uniform spatiotemporal distributions of oxygen, nutrients, and metabolic wastes in 2D, and the tissue‐like architecture, cell–cell, and cell–extracellular matrix interactions only achieved in 3D. The microfluidic platform is made from an organically modified ceramic material, which is inherently biocompatible and supports cell adhesion (2D culture) and metal adhesion (for integration of impedance electrodes to monitor cell proliferation). To induce 3D spheroid formation on another area, a single‐step lithography process is used to fabricate concave microwells, which are made cell‐repellant by nanofunctionalization (i.e., plasma porosification and hydrophobic coating). Thanks to the concave shape of the microwells, the spheroids produced on‐chip can also be released, with the help of microfluidic flow, for further off‐chip characterization after culturing. In this study, the methodology is evaluated for drug cytotoxicity assessment on human hepatocytes.     

Complete minimal submanifolds of compact Lie groups

We give a new method for manufacturing complete minimal submanifolds of compact Lie groups and their homogeneous quotient spaces. For this we make use of harmonic morphisms and basic representation theory of Lie groups. We then employ our method to construct many examples of compact minimal submanifolds of the special unitary groups.     

Ultrafast Multidimensional Laplace NMR Using a Single‐Sided Magnet

Laplace NMR (LNMR) consists of relaxation and diffusion measurements providing detailed information about molecular motion and interaction. Here we demonstrate that ultrafast single‐ and multidimensional LNMR experiments, based on spatial encoding, are viable with low‐field, single‐sided magnets with an inhomogeneous magnetic field. This approach shortens the experiment time by one to two orders of magnitude relative to traditional experiments, and increases the sensitivity per unit time by a factor of three. The reduction of time required to collect multidimensional data opens significant prospects for mobile chemical analysis using NMR. Particularly tantalizing is future use of hyperpolarization to increase sensitivity by orders of magnitude, allowed by single‐scan approach.     

An efficient algorithm for solving nonlinear equations with a minimal number of trial vectors: applications to atomic-orbital based coupled-cluster theory

The conjugate residual with optimal trial vectors (CROP) algorithm is developed. In this algorithm, the optimal trial vectors of the iterations are used as basis vectors in the iterative subspace. For linear equations and nonlinear equations with a small-to-medium nonlinearity, the iterative subspace may be truncated to a three-dimensional subspace with no or little loss of convergence rate, and the norm of the residual decreases in each iteration. The efficiency of the algorithm is demonstrated by solving the equations of coupled-cluster theory with single and double excitations in the atomic orbital basis. By performing calculations on H(2)O with various bond lengths, the algorithm is tested for varying degrees of nonlinearity. In general, the CROP algorithm with a three-dimensional subspace exhibits fast and stable convergence and outperforms the standard direct inversion in iterative subspace method.     

Chirality transfer. A stereospecific palladium salt catalyzed phenylation of chiral butenols.

(R)-(|) and (S)-(+)-3-phenyl butanones have been obtained by a 20% stereospecific palladium catalyzed β-phenylation of the corresponding chiral butenols, the catalyst acting preferentially, through an alkoxide complex, by one face of the alcohol double bond, e.g. the si face of (R)-(|)3-butene-2-ol(I).     

Thermodynamics of aqueous solutions of methyldiethanolamine and diisopropanolamine

The vapour–liquid equilibrium (VLE) of the systems of water + methyldiethanolamine (MDEA) and water + diisopropanolamine (DIPA) was measured at several temperatures with a static total pressure apparatus. The solid–liquid equilibrium (SLE) of the same systems was measured at low amine concentrations by means of two experimental methods: a visual method and a Differential Scanning Calorimeter (DSC). The activity coefficients of water + MDEA were modelled with the NRTL equations. The model parameters were regressed from VLE, SLE and excess enthalpy data from this work and from the literature. The model developed in this work was compared with models found in the literature. The NRTL equations were also used to model the activity coefficients of the system of water + DIPA. The model parameters were fitted from the VLE and SLE data measured in this work.     

Environmental and food analysis by desorption atmospheric pressure photoionization‐mass spectrometry

Desorption atmospheric pressure photoionization‐mass spectrometry (DAPPI‐MS) is a versatile surface analysis technique for a wide range of analytes, especially for neutral and non‐polar analytes. Here, a set of analytes typically found in environmental or food samples was analyzed by DAPPI‐MS. The set included five polyaromatic hydrocarbons (PAHs), one N‐PAH, one brominated flame retardant, and nine pesticides, which were studied with three different spray solvents: acetone and toluene in positive ion mode, and anisole in negative ion mode. The analytes showed [M + H]⁺, M^+?, and [M–H]^? ions as well as fragmentation and substitution products. Detection limits for the studied compounds ranged from 30 pg to 1 ng (from 0.14 to 5.6 pmol). To demonstrate the feasibility of the use of DAPPI‐MS two authentic samples – a circuit board and orange peel – and a spiked soil sample were analyzed. Tetrabromobisphenol A, imazalil, and PAHs were observed from the three above‐mentioned samples, respectively. The method is best suited for rapid screening analysis of environmental or food samples. Copyright © 2010 John Wiley & Sons, Ltd.