HPLC Characterization of the Association Mechanism of Organic Compounds with β Cyclodextrin Using a Novel Boron Nitride Nanotube Particulate Stationary Phase

In this paper, a simple homogeneous coating of silica spherical particles with pristine boron nitride nanotubes (BNNTs) was described. BNNTs dissolved in dimethylacetamide (DMAc) were mixed with amino-functionalized silica particles having a 5 μm diameter. Favorable interaction between the amino group and the BNNT surfaces induces the absorption of the BNNTs on the silica. The BNNT-coated silica particles were used as stationary phase for HPLC. For the first time, it was demonstrated that this new particulate BNNT stationary phase can be used for the study of the complexation of solute molecules (terpene molecules used as test drugs in this work) with β cyclodextrin (βCD). The apparent formation constants Kf of terpene derivative/βCD were in the same magnitude as those reported in the literature. The plot of Kf versus the water fraction in the methanol/water mobile phase showed that the BNNT surface played an active role in the complex formation due to terpene/BNNT-specific polar interactions. This work demonstrated that our novel particulate BNNT HPLC stationary phase was an efficient tool to study molecular recognition mechanism and more specifically the association between a drug substance and a target molecule with the aim of reaching biopharmaceutic and clinical applications.     

Electrically detected electron-spin-echo envelope modulation: a highly sensitive technique for resolving complex interface structures

We show that the electrical detection of electron-spin-echo envelope modulation (ESEEM) is a highly sensitive tool to study interfaces. Taking the Si/SiO2 interface defects in phosphorus-doped crystalline silicon as an example, we find that the main features of the observed echo modulation pattern allow us to develop a microscopic model for the dangling-bond-like P(b0) center by comparison with the results of ab initio calculations. The ESEEM spectrum is found to be far more sensitive to the defect characteristics than the spectrally resolved hyperfine splitting itself.     

Dynamic modeling and simulation of a real world billiard

Gravitational billiards provide an experimentally accessible arena for testing formulations of nonlinear dynamics. We present a mathematical model that captures the essential dynamics required for describing the motion of a realistic billiard for arbitrary boundaries. Simulations of the model are applied to parabolic, wedge and hyperbolic billiards that are driven sinusoidally. Direct comparisons are made between the model?s predictions and previously published experimental data. It is shown that the data can be successfully modeled with a simple set of parameters without an assumption of exotic energy dependence.     

Synthesis of enantiopure substituted piperidines via an aziridinium ring expansion

Herein we report a novel methodology for the asymmetric synthesis of 3-substituted piperidines from readily available chiral building blocks. This method, which features a novel irreversible dihydropyrole-tetrahydropyridine ring expansion, allows the introduction of a large variety of substituents at the 3-position and permits substitution at the 2- and 6-position giving mono-, di-, or trisubstituted piperidines with high diastereocontrol.     

SModelS: a tool for interpreting simplified-model results from the LHC and its application to supersymmetry

We present a general procedure to decompose Beyond the Standard Model (BSM) collider signatures presenting a $\mathbb {Z}_2$ symmetry into Simplified Model Spectrum (SMS) topologies. Our method provides a way to cast BSM predictions for the LHC in a model independent framework, which can be directly confronted with the relevant experimental constraints. Our concrete implementation currently focusses on supersymmetry searches with missing energy, for which a large variety of SMS results from ATLAS and CMS are available. As show-case examples we apply our procedure to two scans of the minimal supersymmetric standard model. We discuss how the SMS limits constrain various particle masses and which regions of parameter space remain unchallenged by the current SMS interpretations of the LHC results.     

Interference of Different Types of Mastication on Static Balance in Individuals without Temporomandibular Disorder

Purpose: This study was to determine whether non-habitual (isotonic) bilateral and unilateral mastication with eyes open and eyes closed exerts an influence on static balance in individuals without temporomandibular disorder (TMD). Method: An observational, cross-sectional study was conducted involving 20 volunteers aged 20 to 40 years without temporomandibular disorder. Static balance was assessed with the individuals in a quiet standing position on a force plate performing different types of mastication under six separate conditions. Results: Significant differences (p < .05) were found in the area of oscillation during bilateral mastication (eyes open) and the right unilateral mastication, significant differences were only found for oscillation area with eyes open and mediolateral center of pressure with eyes closed (p < .05). Conclusions: The findings of the present study reveal that the stomatognathic system (bilateral and unilateral mastication) promote changes in some variables of static balance.     

Laser Beam Filtration for High Spatial Resolution MALDI Imaging Mass Spectrometry

We describe an easy and inexpensive way to provide a highly defined Gaussian shaped laser spot on target of 5 μm diameter for imaging mass spectrometry using a commercial MALDI TOF instrument that is designed to produce a 20 μm diameter laser beam on target at its lowest setting. A 25 μm pinhole filter on a swivel arm was installed in the laser beam optics outside the vacuum ion source chamber so it is easily flipped into or out of the beam as desired by the operator. The resulting ion images at 5 μm spatial resolution are sharp since the satellite secondary laser beam maxima have been removed by the filter. Ion images are shown to demonstrate the performance and are compared with the method of oversampling to achieve higher spatial resolution when only a larger laser beam spot on target is available.