Hepatoprotective Effects of Berberis vulgaris L. Extract/β Cyclodextrin on Carbon Tetrachloride-Induced Acute Toxicity in Mice

The present study investigated the capacity of formulated Berberis vulgaris extract/β-cyclodextrin to protect liver against CCl(4)-induced hepatotoxicity in mice. Formulated and non-formulated extracts were given orally (50 mg/kg/day) to mice for 7 days and were then intra-peritoneally injected with 1.0 mL/kg CCl(4) on the 8th day. After 24 h of CCl(4) administration, an increase in the levels of apartate-amino-transferase (AST), alanine-amino-transferase (ALT) and malondialdehyde (MDA) was found and a significant decrease in superoxide-dismutase (SOD), catalase (CAT), glutathione (GSH) and glutathione-peroxidase (GPx) levels could be detected. This was accompanied by extended centrilobular necrosis, steatosis, fibrosis and an altered ultrastructure of hepatocytes. Pre-treatment with formulated or non-formulated extract suppressed the increase in ALT, AST and MDA levels and restored the level of antioxidant enzymes at normal values. Histopathological and electron-microscopic examination showed milder liver damage in both pre-treated groups and the protective effect was more pronounced after the formulated extract was administered. Internucleosomal DNA fragmentation induced by CCl(4) was reduced in the group which received non-formulated extract and absent in the group which received formulated extract. Taken together, our results suggest that Berberis vulgaris/β-cyclodextrin treatment prevents hepatic injury induced by CCl(4) and can be considered for further nutraceutical studies.     

The state of strain in single GaN nanocolumns as derived from micro-photoluminescence measurements

In the present paper, studies on the state of strain in single and ensembles of nanocolumns investigated by photoluminescence spectroscopy will be presented. The GaN nanocolumns were either grown in a bottom-up approach or prepared in a top-down approach by etching compact GaN layers grown on Si(111) and sapphire (0001) substrates. Experimental evidence for strain relaxation of the nanocolumns was found. The difference and development of the strain value for different nanocolumns could be verified by spatially resolved micro-photoluminescence on single nanocolumns separated from their substrate. A common D0X spectral position at 3.473 eV was found for all separated single GaN nanocolumns independent of the substrate or processing technique used, as expected for a relaxed system.     

Abelès method revisited

The Abelès method is a classical method for determining the refractive index of dielectric thin films. In this paper we examine the main features of the method in a formal manner, using closed-form equations, and we show that the method is ambiguous in certain yet unreported situations.     

Noise reduction for enhanced component identification in multi-dimensional biomolecular NMR studies

The objective of the research presented in this paper is to shed light into the benefits of multi-dimensional wavelet-based methodology applied to NMR biomolecular data analysis. Specifically, the emphasis is on noise reduction for enhanced component identification in multi-dimensional mixture regression. The contributions of this research are multi-fold. First, the wavelet-based noise reduction method applies to multi-dimensional data whereas most of the existing work focuses on one- or two-dimensional data only. The proposed wavelet-based methodology is founded on rigorous analysis of the dependence between wavelet coefficients, an important aspect of multi-dimensional wavelet de-noising. The wavelet de-noising rule is based on Stein’s unbiased risk estimator (SURE) where the smoothness thresholds vary with the resolution level and orientation of the wavelet transform and selected by controlling the False Discovery Rate of the significant wavelet coefficients. Second, this paper highlights the application of the wavelet methodology to multi-dimensional NMR data analysis for protein structure determination. The noise reduction method is general and applicable to multi-dimensional data arising in many other research fields, prominently in biology science. Our empirical investigation shows that reducing the noise using the method in this paper results in more detectable true components and fewer false positives without altering the shape of the significant components.     

Microcoil-based MRI: feasibility study and cell culture applications using a conventional animal system

Object  

The aim of this study was to demonstrate the feasibility of MR microimaging on a conventional 9.4 T horizontal animal MRI system using commercial available microcoils in combination with only minor modifications to the system, thereby opening this field to a larger community.     

Interactions of Chemically Synthesized Ferrihydrite Nanoparticles with Human Serum Transferrin: Insights from Fluorescence Spectroscopic Studies

Human serum transferrin (HST) is a glycoprotein involved in iron transport that may be a candidate for functionalized nanoparticles to bind and target cancer cells. In this study, the effects of the simple and doped with cobalt (Co) and copper (Cu) ferrihydrite nanoparticles (Fh-NPs, Cu-Fh-NPs, and Co-Fh-NPs) were studied by spectroscopic and molecular approaches. Fluorescence spectroscopy revealed a static quenching mechanism for all three types of Fh-NPs. All Fh-NPs interacted with HST with low affinity, and the binding was driven by hydrogen bonding and van der Waals forces for simple Fh-NPs and by hydrophobic interactions for Cu-Fh-NPs and Co-Fh-NPs binding, respectively. Of all samples, simple Fh-NPs bound the most to the HST binding site. Fluorescence resonance energy transfer (FRET) allowed the efficient determination of the energy transfer between HST and NPs and the distance at which the transfer takes place and confirmed the mechanism of quenching. The denaturation of the HST is an endothermic process, both in the case of apo HST and HST in the presence of the three types of Fh-NPs. Molecular docking studies revealed that Fh binds with a low affinity to HST (K_a = 9.17 × 10³ M⁻¹) in accord with the fluorescence results, where the interaction between simple Fh-NPs and HST was described by a binding constant of 9.54 × 10³ M⁻¹.     

Influence of microfibrillated cellulose and soft biocomponent on the morphology and thermal properties of thermoplastic polyurethanes

Composite materials from thermoplastic polyurethanes (TPUs) with biodegradable segments and microfibrillated cellulose (MFC) were developed as alternatives to traditional materials used in packaging or biomedical applications. Two TPUs were synthesized by the prepolymer method starting from different soft segments, poly(ε-caprolactone)/poly(butylene adipate) (PUBA) or poly(ε-caprolactone)/poly(ethylene oxide) (PUEO), and isophorone diisocyanate/aliphatic chain extender. Proton nuclear magnetic resonance (¹H NMR) confirmed the structure and Fourier transform infrared spectroscopy (FTIR) along with scanning electron microscopy showed that the soft segments with different hydrophobicity led to a higher phase mixing in PUBA and improved microphase separation in PUEO. MFC was added in the TPUs with different soft segments to increase biocompatibility, strength, and degradation rate. A better thermal stability, a gradual increase of crystallinity and a better dispersion of MFC were noticed in PUEO composites compared to PUBA ones. The crystallinity increased with 78% and 50% in PUBA and PUEO composites with 5 wt% MFC compared to the neat polyurethanes showing the nucleating ability of MFC. In addition, the enhanced storage modulus, with 75% and 25% in PUEO and PUBA composites, highlighted the reinforcing efficiency of MFC. Therefore, the addition of MFC to the already synthesized TPUs allows tailoring the morphology and thermal properties of TPUs for industrial application.     

Synthesis of poly(N‐isopropylacrylamide) under atmospheric pressure plasma conditions

This work is focused on obtaining and characterizing thin films of a certain thermosensitive polymer, i.e., poly(N‐isopropylacrylamide). To obtain such polymers dielectric barrier discharge plasma working at atmospheric pressure in plan–plan geometry was used. The plasma parameters were monitored during polymerization reaction by its electrical and optical signals. The obtained films were analyzed by different techniques such as X‐photoelectron spectroscopy, Fourier transform infrared spectroscopy, atomic force microscopy, contact angle, impedance spectroscopy measurements, and light interferometry for thickness measurements. Chemical analyses of obtained films showed that they sort well with the polymers obtained by other methods in literature. It has been proved that plasma polymerized films have a superhydrophilic character at room temperature, the measured contact angle being around 13°, the lower critical solution temperature was also identified at about 30–31°C. The films' thickness for a 10‐min duration deposition was 400 nm. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Design of New Camelina Oil‐Based Hydrophilic Monomers for Novel Polymeric Materials

Triglyceride‐based monomers represent a competitive alternative to petrochemical resources in the macromolecular compounds area. In the current study, several types of hydrophilic camelina oil (CO)‐based monomers were synthesized using tunable experimental protocols that involve three different steps: first—conversion of the double bonds into epoxy rings, second—partial opening of the epoxy rings and methacrylic groups grafting and last—opening of the unreacted epoxy rings and hydrophilic units attaching. 1H‐NMR, 13C‐NMR and FTIR spectroscopy demonstrate the success of the CO functionalization with polymerizable and hydrophilic moieties—polyethylene glycol units—with different molecular weights, exhibiting self‐emulsifiable properties. Several bulk and emulsion polymerization tests were performed for the synthesized monomers and their ability to build polymer networks using different photo‐chemical procedures (using visible and UV radiations respectively) was demonstrated, without additional surfactants. FTIR spectroscopy indicates the polymerization success by the disappearance of the specific bands assigned to the double bonds from methacrylic groups and thermogravimetric analysis demonstrates that the emulsion polymerization leads to materials with an improved thermostability.