Combinations of Piperine with Hydroxypropyl-β-Cyclodextrin as a Multifunctional System

Piperine is an alkaloid that has extensive pharmacological activity and impacts other active substances bioavailability due to inhibition of CYP450 enzymes, stimulation of amino acid transporters and P-glycoprotein inhibition. Low solubility and the associated low bioavailability of piperine limit its potential. The combination of piperine with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) causes a significant increase in its solubility and, consequently, an increase in permeability through gastrointestinal tract membranes and the blood–brain barrier. X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) were used to characterize interactions between piperine and HP-β-CD. The observed physicochemical changes should be combined with the process of piperine and CD system formation. Importantly, with an increase in solubility and permeability of piperine as a result of interaction with CD, it was proven to maintain its biological activity concerning the antioxidant potential (2,2-diphenyl-1-picryl-hydrazyl-hydrate assay), inhibition of enzymes essential for the inflammatory process and for neurodegenerative changes (hyaluronidase, acetylcholinesterase, butyrylcholinesterase).     

Thermo-protective properties of polymer composites with nano-titanium dioxide

International Journal of Mechanics and Materials in Design - The present work investigates the ablative and thermal properties of an epoxy resin which was modified with titanium dioxide...     

Potential tissue implants from the networks based on 1,5-dioxepan-2-one and ε-caprolactone

The synthesis and characterization of degradable polymeric networks for biomedical applications was performed. Cross-linked films of poly(ε-caprolactone) (PCL) and poly(1,5-dioxepan-2-one) (PDXO) having various mole fractions of monomers and different cross-link densities were successfully prepared using 2,2′-bis-(ε-caprolactone-4-yl) propane (BCP) as cross-linking agent. Reaction parameters were carefully examined to optimise the film-forming conditions. Networks obtained were elastomeric materials, easy to cast and remove from the mould. Effect of CL content and cross-link density on the final properties of the polymer network was evaluated. High CL content or degree of cross-linking led to increase in Young's modulus and decrease in elongation at break. An increase in crystalline domains in films having a higher CL content was observed by optical microscopy. A greater thermal stability was observed in films having a high CL content. The hydrophilicity of the materials could be tailored by changing the CL content. The surface of the films became rougher with higher CL content.     

Sensitivity analysis of the scattering parameters of microwave filters using the adjoint network method

A novel approach is presented to calculate the sensitivities of the scattering parameters of microwave filters obtained with the full‐wave mode‐matching (MM) technique. Using only the MM simulation of the original network, the sensitivities of the scattering parameters with respect to all designable parameters are obtained. The adjoint network method (ANM) is applied to the generalized scattering matrices of the different filter components. This guarantees good accuracy of the calculated sensitivities. The implementation details are discussed for N‐resonator ridge waveguide filters. Excellent agreement is obtained between the sensitivities calculated using ANM and those obtained using the expensive central differences. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.     

Lipid damage in farmed rainbow trout (Oncorhynchus mykiss) after slaughtering and chilled storage

The flow ice system including ozone (OFI condition) was tested for slaughtering and storage (up to 16 days) of farmed rainbow trout (Oncorhynchus mykiss). Lipid damage analyses were carried out and compared to sensory acceptance and instrumental colour changes. Comparison to individuals processed with the flow ice system in the absence of ozone (FI condition) was undertaken. Rainbow trout slaughtered and chilled under FI and OFI conditions showed a low lipid damage development, according to lipid oxidation and hydrolysis events and lipid composition (polyunsaturated fatty acids, phospholipids and endogenous antioxidants) changes. Additionally, both icing conditions led to largely good quality and shelf life times and to the absence of changes in colour properties. It is concluded that flow ice as such, or including the presence of ozone, can be considered as ideal strategy to be employed as slaughtering and storage system during the commercialisation of the actual farmed species. The ozone presence has shown some profitable effects as leading to an extended shelf life time by quality retention of several sensory parameters; in contrast, some negligible negative effects could be observed on the secondary and tertiary lipid oxidation development. However, the oxidation values reached by individuals kept under OFI conditions cannot be considered as particularly high.     

Differential effect of two calcium channel blockers--nifedipine and diltiazem--on atherogenesis in hypercholesterolemic hamster

Previous studies report that background luminance flicker, which is asynchronous with signal averaging, reduces the amplitude and increases the latency of the pattern-onset visual evoked potential (VEP). This effect has been attributed to saturation of the magnocellular (m-) pathway by the flicker stimulus. In the current study, we evaluate this hypothesis and further characterize this effect. We found that flicker had similar effects on the pattern-onset and pattern-reversal VEP, suggesting that the reversal and onset responses have similar generators. Chromatic flicker decreased latency of the chromatic VEP whereas luminance flicker increased peak latency to luminance targets. This result indicates that luminance flicker saturates a rapidly conducting m-pathway whereas chromatic flicker saturates a more slowly conducting parvocellular (p-) pathway. Finally, evoked potentials to chromatic and luminance stimuli were recorded from 34 electrodes over the scalp in the presence of static and asynchronously modulated backgrounds. An equivalent dipole model was used to assess occipital, parietal, and temporal lobe components of the surface response topography. Results showed that chromatic flicker reduced activity to a greater extent in the ventral visual pathway whereas luminance flicker reduced activity to a greater extent in the dorsal visual pathway to parietal lobe. We conclude that the VEP to isoluminant color and luminance stimuli contains both m- and p-pathway components. Asynchronous flicker can be used to selectively reduce the contribution of these pathways to the surface recorded VEP. Our results provide evidence of parallel pathways in the human visual system, with a dorsal luminance channel projecting predominantly to the posterior parietal lobe and a ventral color channel projecting predominantly to inferior temporal lobe.     

Response time variability

Response time variability is a new optimization problem with a broad range of applications and a distinctive number of theoretic flavour. The problem occurs whenever events, jobs, clients or products need to be sequenced so as to minimize the variability of time for which they wait for the next turn in obtaining the resources necessary for their advance. The problem has numerous real-life applications. We study its computational complexity, present efficiency, polynomial time algorithms for some cases, and the NP-hardness proof for a general problem. We propose a position exchange heuristic and apply it to improve the total response time variability of an initial sequence. The latter is the optimum bottleneck sequence, Webster or Jefferson sequence of the apportionment, or a random sequence. We report on computational experiments with the heuristic.     

A performance- and energy-oriented extended tuning process for time-step-based scientific applications

The Journal of Supercomputing - Scientific application codes are often long-running time- and energy-consuming parallel codes, and the tuning of these methods towards the characteristics of a...     

Annotation of sentence structure

The focus of this article is on the creation of a collection of sentences manually annotated with respect to their sentence structure. We show that the concept of linear segments—linguistically motivated units, which may be easily detected automatically—serves as a good basis for the identification of clauses in Czech. The segment annotation captures such relationships as subordination, coordination, apposition and parenthesis; based on segmentation charts, individual clauses forming a complex sentence are identified. The annotation of a sentence structure enriches a dependency-based framework with explicit syntactic information on relations among complex units like clauses. We have gathered a collection of 3,444 sentences from the Prague Dependency Treebank, which were annotated with respect to their sentence structure (these sentences comprise 10,746 segments forming 6,341 clauses). The main purpose of the project is to gain a development data—promising results for Czech NLP tools (as a dependency parser or a machine translation system for related languages) that adopt an idea of clause segmentation have been already reported. The collection of sentences with annotated sentence structure provides the possibility of further improvement of such tools.