Evaluation of the shadow effect in terahertz kinoform gratings.

The experimental and numerical evaluation of the shadow effect in kinoform diffractive gratings for the terahertz (THz) range is given. This effect limits the diffractive efficiency of dense gratings, which are the base of the elements suited for convenient beam focusing and imaging in THz. The observed effect of redirecting most of the incident energy into stray -1st diffractive order is observed and discussed.

Role of preprocedural glutathione concentrations in the prediction of major adverse cardiac events in patients with acute coronary syndrome treated with percutaneous coronary intervention.

Introduction: Poor antioxidant protection of cardiomyocytes due to cardiac ischemia and low serum levels of reduced glutathione (GSH) may be associated with enhanced risk of coronary restenosis after primary percutaneous coronary intervention (pPCI).

Objectives: The aim of this study was to investigate whether preprocedural serum reduced GSH, reflecting the antioxidant status, may be predictive of major adverse cardiac events (MACE) in patients with acute coronary syndrome (ACS) treated with pPCI.

Patients And Methods: Preprocedural serum GSH level was evaluated in 141 patients with ACS treated with pPCI with bare-metal stent (BMS) deployment.

Toward engineering efficient peptidomimetics. Screening conformational landscape of two modified dehydroaminoacids.

Effective peptidomimetics should posses structural rigidity and appropriate interaction pattern leading to potential spatial and electronic matching to the target receptor site. Rational design of such small bioactive molecules could push chemical synthesis and molecular modeling toward faster progress in medicinal chemistry. Conformational properties of N-t-butoxycarbonyl-glycine-(E/Z)-dehydrophenylalanine N',N'-dimethylamides (Boc-Gly-(E/Z)-ΔPhe-NMe2 ) in chloroform were studied by NMR and IR spectroscopy.

Physisorption of functionalized gold nanoparticles on AlGaN/GaN high electron mobility transistors for sensing applications.

AlGaN/GaN high electron mobility transistors (HEMTs) were used to measure electrical characteristics of physisorbed gold nanoparticles (Au NPs) functionalized with alkanethiols with a terminal methyl, amine, or carboxyl functional group. Additional alkanethiol was physisorbed onto the NP treated devices to distinguish between the effects of the Au NPs and alkanethiols on HEMT operation. Scanning Kelvin probe microscopy and electrical measurements were used to characterize the treatment effects.

Two phosphonodehydrotripeptides: Boc0-Gly1-Δ(Z)Phe2-α-Abu3PO3Me2 and Boc0-Gly1-Δ(Z)Phe2-α-Nva3PO3Et2.

The present paper reports the crystal structures of two short phosphonotripeptides (one in two crystal forms) containing one ΔPhe (dehydrophenylalanine) residue, namely dimethyl (3-{[tert-butoxycarbonylglycyl-α,β-(Z)-dehydrophenylalanyl]amino}propyl)phosphonate, Boc(0)-Gly(1)-Δ(Z)Phe(2)-α-Abu(3)PO3Me2, C21H32N3O7P, (I), and diethyl (4-{[tert-butoxycarbonylglycyl-α,β-(Z)-dehydrophenylalanyl]amino}butyl)phosphonate, Boc(0)-Gly(1)-Δ(Z)Phe(2)-α-Nva(3)PO3Et2, as the propan-2-ol monosolvate 0.122-hydrate, C24H38N3O7P·C3H8O·0.122H2O, (II), and the ethanol monosolvate 0.

Purification and partial characterization of aminopeptidase from barley (Hordeum vulgare L.) seeds.

Aminopeptidases (EC 3.4.11) are proteolytic enzymes, which hydrolyze one amino acid from N-terminus of peptidic substrates.

Quantum-chemical studies on the favored and rare tautomers of neutral and redox adenine.

All possible twenty-three prototropic tautomers of neutral and redox adenine (nine amine and fourteen imine forms, including geometric isomerism of the exo ═NH group) were examined in vacuo {DFT(B3LYP)/6-311+G(d,p)}. The NH → NH conversions as well as those usually omitted, NH → CH and CH → CH, were considered. An interesting change of the tautomeric preference occurs when proceeding from neutral to reduced adenine.

Diffuserless holographic projection working on twin spatial light modulators.

An improved efficient projection of holographic images is presented. It uses two phase spatial light modulators (SLMs) with two iteratively optimized Fresnel holograms displayed simultaneously--each for one modulator. The phase distribution on the second modulator is taking into account the light distribution coming from the first one.

The intra-observer reproducibility of cardiovascular magnetic resonance myocardial feature tracking strain assessment is independent of field strength.

Background: Cardiovascular magnetic resonance myocardial feature tracking (CMR-FT) is a promising novel method for quantification of myocardial wall mechanics from standard steady-state free precession (SSFP) images. We sought to determine whether magnetic field strength affects the intra-observer reproducibility of CMR-FT strain analysis.

Methods: We studied 2 groups, each consisting of 10 healthy subjects, at 1.

Simple holographic projection in color.

Extremely simplified image projection technique based on optical fibers and a single Spatial Light Modulator is presented. Images are formed by addressing the modulator with especially iterated Fourier holograms, precisely aligned on the projection screen using phase factors of lenses and gratings. Focusing is done electronically with no moving parts.

Modeling of the optical system illuminated by quasi-monochromatic spatially incoherent light: new numerical approach.

This Letter presents a new method for modeling of complex optical setups illuminated by quasi monochromatic spatially incoherent light. The algorithm provides better performance and quality than other modeling methods both for isoplanatic and nonisoplanatic systems. The algorithm maintains energy relations, image orientation, and magnification of the system.

Diffractive paper lens for terahertz optics.

Passive terahertz (THz) setups require optical elements with large diameters for optimal harvesting of weak signals. High f-number implies sophisticated aspheric designs to ensure optimal resolution and good energetic efficiency. Trial and error testing of such optics is expensive and numerical modeling is time consuming; hence, we propose extremely cheap diffractive lenses for THz made of regular paper.

Fully automated derivation of coronary artery calcium scores and cardiovascular risk assessment from contrast medium-enhanced coronary CT angiography studies.

Objectives: Performance evaluation of a fully automated system for calculating computed tomography (CT) coronary artery calcium scores from contrast medium-enhanced coronary CT angiography (cCTA) studies.

Methods: One hundred and twenty-seven patients (58 ± 11 years, 71 men) who had undergone cCTA as well as an unenhanced CT calcium scoring study where included. Calcium scores were computed from cCTA by an automated image processing algorithm and compared with calcium scores obtained by standard manual assessment of unenhanced CT calcium scoring studies.

Mechanical properties of poly(dimethylsiloxane)-block-poly(2-methyloxazoline) polymersomes probed by atomic force microscopy.

Poly(dimethylsiloxane)-block-poly(2-methyloxazoline) (PDMS-b-PMOXA) vesicles were characterized by a combination of dynamic light scattering (DLS), cryogenic transmission electron microscopy (cryo-TEM), and atomic force microscopy imaging and force spectroscopy (AFM). From DLS data, a hydrodynamic radius of ~150 nm was determined, and cryo-TEM micrographs revealed a bilayer thickness of ~16 nm. In AFM experiments on a silicon wafer substrate, adsorption led to a stable spherical caplike conformation of the polymersomes, whereas on mica, adsorption resulted also in vesicle fusion and formation of bilayer patches or multilayer stacks.

Single breath-hold assessment of cardiac function using an accelerated 3D single breath-hold acquisition technique--comparison of an intravascular and extravascular contrast agent.

Background: Cardiovascular magnetic resonance (CMR) is the current gold standard for the assessment of left ventricular (LV) function. Repeated breath-holds are needed for standard multi-slice 2D cine steady-state free precession sequences (M2D-SSFP). Accelerated single breath-hold techniques suffer from low contrast between blood pool and myocardium.

Highly efficient broadband double-sided Fresnel lens for THz range.

Modern passive THz setups require effective optical elements with a large numerical aperture. Here we propose a new type of the optical element for THz applications, which is a broadband double-sided Fresnel-like lens with an optimized thickness. The optimization is performed to obtain a very low attenuation, low material cost, and small weight in the element media.

Three-dimensional imaging of the aortic vessel wall using an elastin-specific magnetic resonance contrast agent.

Objective: The aim of this study was to demonstrate the feasibility of high-resolution 3-dimensional aortic vessel wall imaging using a novel elastin-specific magnetic resonance contrast agent (ESMA) in a large animal model.

Materials And Methods: The thoracic aortic vessel wall of 6 Landrace pigs was imaged using a novel ESMA and a nonspecific control agent. On day 1, imaging was performed before and after the administration of a nonspecific control agent, gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA; Bayer Schering AG, Berlin, Germany).

Application of explicitly localized molecular orbitals to electronic structure calculations.

We have recently generalized the method for localizing orbitals on a set of predefined molecular fragments [Phys. Chem. Chem.

Toward temperature-dependent coarse-grained potentials of side-chain interactions for protein folding simulations. II. Molecular dynamics study of pairs of different types of interactions in water at various temperatures.

By means of molecular dynamics simulations of 15 pairs of molecules selected to model the interactions of nonpolar, nonpolar and polar, nonpolar and charged, polar, and polar and charged side chains in water, we determined the potentials of mean force (PMFs) of pairs of interacting molecules in water as functions of distance between the interacting particles or their distance and orientations at three temperatures: 283, 323, and 373 K, respectively. The systems were found to fall into the following four categories as far as the temperature dependence of the PMF is concerned: (i) pairs for which association is entropy-driven, (ii) pairs for which association is energy-driven, (iii) pairs of positively charged solute molecules, for which association is energy-driven with unfavorable entropy change, and (iv) the remaining systems for which temperature dependence is weak. For each pair of PMFs, entropic and energetic contributions have been discussed.

Discovery of new piperidine amide triazolobenzodiazepinones as intestinal-selective CCK1 receptor agonists.

New cholecystokinin-1 receptor (CCK1R) agonist 'triggers' were identified using iterative library synthesis. Structural activity relationship studies led to the discovery of compound 10e, a potent CCK1R agonist that demonstrated robust weight loss in a diet-induced obese rat model with very low systemic exposure. Pharmacokinetic data suggest that efficacy is primarily driven through activation of CCK1R's located within the intestinal wall.

Platelets in cardiovascular imaging.

Coronary artery disease remains a major hazard within the western world despite early revascularisation and advanced medical therapy strategies. One of its major substrates is platelet activation and thrombus formation, triggering acute events such as myocardial infarction and ischemic strokes. There are a variety of non-invasive imaging strategies being translated from bench to bedside into clinical practice that tackle specific aspects of the pathophysiology of thrombus formation.

In vivo assessment of intraplaque and endothelial fibrin in ApoE(-/-) mice by molecular MRI.

Objective: Molecular magnetic resonance imaging (MRI) has emerged as a promising non-invasive modality to characterize atherosclerotic vessel wall changes on a morphological and molecular level. Intraplaque and endothelial fibrin has recently been recognized to play an important role in the progression of atherosclerosis. This study aimed to investigate the feasibility of intraplaque and endothelial fibrin detection using a fibrin-targeted contrast-agent, FTCA (EPIX Pharmaceuticals, Lexington, MA), in a mouse model of atherosclerosis.

Comparative studies on IR, Raman, and surface enhanced Raman scattering spectroscopy of dipeptides containing ΔAla and ΔPhe.

Three dipeptides containing dehydroresidues (ΔAla, Δ((Z))Phe, and Δ((E))Phe) were examined by IR, Raman, and surface-enhanced Raman techniques for the first time. The effect of the size and isomer type of the β-substituent in the dehydroresidue on the conformational structure of the peptide was evaluated by using the analysis of IR and Raman bands. Additionally, SERS spectroscopy provided insight into the adsorption mechanism of these species on the metal surface.

Cardiovascular magnetic resonance imaging in small animals.

Noninvasive imaging studies involving small animals are becoming increasingly important in preclinical pharmacological, genetic, and biomedical cardiovascular research. Especially small animal magnetic resonance imaging (MRI) using high field and clinical MRI systems has gained significant importance in recent years. Compared to other imaging modalities, like computer tomography, MRI can provide an excellent soft tissue contrast, which enables the characterization of different kinds of tissues without the use of contrast agents.

Gallium nitride is biocompatible and non-toxic before and after functionalization with peptides.

The toxicity of semiconductor materials can significantly hinder their use for in vitro and in vivo applications. Gallium nitride (GaN) is a material with remarkable properties, including excellent chemical stability. This work demonstrated that functionalized and etched GaN surfaces were stable in aqueous environments and leached a negligible amount of Ga in solution even in the presence of hydrogen peroxide.