Water state in chemically and physically crosslinked chitosan membranes

Chemically and physically crosslinked chitosan membranes were prepared by treating chitosan (Ch) with glutaraldehyde (GA) and sulfuric acid (SA). FTIR and XRD results were employed to confirm the formation of covalent and ionic crosslinks between Ch, GA, and SA. The states of water in non‐crosslinked and covalently and ionically crosslinked chitosan membranes containing different amount of water were investigated by low temperature differential scanning calorimetry measurements. The equilibrium swelling in water was examined gravimetrically. Two types of water were found in the polymer samples, i.e., freezing water and non‐freezing water. The effect of crosslinking process on water state and water uptake was analyzed. The water uptake decreased after chitosan crosslinking with GA, but significantly increased after later crosslinking with SA. The amount of non‐freezing water was generally smaller in crosslinked membranes. An impact of molecular and supermolecular structure on water uptake and state of water in non‐crosslinked and crosslinked chitosan membranes was discussed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1707–1715, 2013     

Sorption-induced effects of humic substances on mass transfer of organic pollutants through aqueous diffusion boundary layers: the example of water/air exchange

This study examines the effect of dissolved humic substances (DHS) on the rate of water-gas exchange of organic compounds under conditions where diffusion through the aqueous boundary layer is rate-determining. A synthetic surfactant was applied for comparison. Mass-transfer coefficients were determined from the rate of depletion of the model compounds by means of an apparatus containing a stirred aqueous solution with continuous purging of the headspace above the solution. In addition, experiments with continuous passive dosing of analytes into the water phase were conducted to simulate a system where thermodynamic activity of the chemical in the aqueous phase is identical in the presence and absence of DHS. The experimental results show that DHS and surfactants can affect water-gas exchange rates by the superposition of two mechanisms: (1) hydrodynamic effects due to surface film formation ("surface smoothing"), and (2) sorption-induced effects. Whether sorption accelerates or retards mass transfer depends on its effect on the thermodynamic activity of the pollutant in the aqueous phase. Mass transfer will be retarded if the activity (or freely dissolved concentration) of the pollutant is decreased due to sorption. If it remains unchanged (e.g., due to fast equilibration with a sediment acting as a large source phase), then DHS and surfactant micelles can act as an additional shuttle for the pollutants, enhancing the flux through the boundary layer.     

Imaging of C-fos Activity in Neurons of the Mouse Parietal Association Cortex during Acquisition and Retrieval of Associative Fear Memory

The parietal cortex of rodents participates in sensory and spatial processing, movement planning, and decision-making, but much less is known about its role in associative learning and memory formation. The present study aims to examine the involvement of the parietal association cortex (PtA) in associative fear memory acquisition and retrieval in mice. Using ex vivo c-Fos immunohistochemical mapping and in vivo Fos-EGFP two-photon imaging, we show that PtA neurons were specifically activated both during acquisition and retrieval of cued fear memory. Fos immunohistochemistry revealed specific activation of the PtA neurons during retrieval of the 1-day-old fear memory. In vivo two-photon Fos-EGFP imaging confirmed this result and in addition detected specific c-Fos responses of the PtA neurons during acquisition of cued fear memory. To allow a more detailed study of the long-term activity of such PtA engram neurons, we generated a Fos-Cre-GCaMP transgenic mouse line that employs the Targeted Recombination in Active Populations (TRAP) technique to detect calcium events specifically in cells that were Fos-active during conditioning. We show that gradual accumulation of GCaMP3 in the PtA neurons of Fos-Cre-GCaMP mice peaks at the 4th day after fear learning. We also describe calcium transients in the cell bodies and dendrites of the TRAPed neurons. This provides a proof-of-principle for TRAP-based calcium imaging of PtA functions during memory processes as well as in experimental models of fear- and anxiety-related psychiatric disorders and their specific therapies.     

Verification of Articulated Arm Coordinate Measuring Machines Accuracy Using LaserTracer System as Standard of Length

This article describes a novel approach to verification of articulated arm coordinate measuring machines (AA CMMs) based on ISO 10360-2 standard. The approach utilizes the LaserTracer (LT) system as standard of length and automation of calibration procedure using an industrial robot. In this method, the robot is programmed to repeatedly move the AA CMM. The retroreflector is integrated with the stylus of AA CMM. Location of the retroreflector is constantly tracked by LaserTracer and, in select positions, the measurements of distance are performed by both the AA CMM and LT system. The verification of AA CMM accuracy is carried out through the comparison of the two measurement values. The developed procedure is recommended mainly for checking AA CMMs with large measuring volume, where the application of common artefacts is usually insufficient, or time-consuming, due to the fact that measurements have to be performed for several subspaces in the AA CMM measuring volume.     

Head‐to‐Head Homo‐Coupling of Arylethynes Catalysed by (Dicarbonyl)ruthenium Chloride Metallacycles: Selective Synthesis of (E)‐1,4‐Diarylbut‐1‐en‐3‐ynes

Exposure of various arylethynes to catalytic amounts of dimeric ruthenacycles containing the chloro(dicarbonyl)ruthenium [Ru(CO)₂Cl] motif efficiently and selectively leads to the formation of (E)‐1,4‐diaryl‐but‐1‐en‐3‐ynes that result from head‐to‐head C C coupling.     

Activity of lysosomal and nonlysosomal proteases of fibrosarcoma induced by methylcholanthrene

Activity of lysosomal (cathepsins A,B,C,D and E) and nonlysosomal proteases (cathepsin G, elastase, collagenase, prolidase, prolinase) was evaluated in fibrosarcoma induced in rats by methylcholanthrene. No differences were found in the activity of the examined proteases in tumours of different size in the external, intermediate and central spheres of these tumours. Activity of cathepsins A,B,C,D,E and G, prolidase and prolinase was higher in the fibrosarcoma and activity of collagenase and elastase was lower than in the rat skin.     

Consumption of raw brown onions variably modulate plasma lipid profile and lipoprotein oxidation in pigs fed a high‐fat diet

This study was undertaken to determine the effects of two commercially available brown onion varieties, ‘Cavalier’ and ‘Destiny’, supplemented at two different levels, on blood lipid and oxidative status using the pig as a model. Twenty‐five female cross‐bred pigs were allocated to one of five dietary treatments that consisted of a high‐fat control diet with no onion added, a low onion dose of 10 g onion MJ^?1 DE and a high dose of 25 g onion MJ^?1 DE for each variety of onion. Supplementation with ‘Destiny’ onion resulted in a 21% (p < 0.05) reduction in the averaged fasted and postprandial plasma triacylglyceride (TG) measurements taken over the six‐week period in comparison with the control pigs. The average fasting and postprandial plasma cholesterol concentrations were significantly reduced by 5.5 and 12.4% in pigs that consumed the low and high dose of ‘Destiny’ onion, respectively (p < 0.010), while ‘Cavalier’ was only effective at lowering cholesterol levels by 10% at the lower dose of supplementation. Inhibition in the rate of serum lipoprotein oxidation, measured as lag time, was increased by 23% (p < 0.05) in plasma obtained from pigs that consumed ‘Cavalier’ compared with the control and ‘Destiny’ onion diets. These data indicate that onion consumption level may provide a dietary means of manipulating some of the risk indices associated with coronary heart disease, but the responses varied with type and dose of onion. Copyright © 2004 Society of Chemical Industry     

Extra‐virgin and refined olive oils decrease plasma triglyceride,moderately affect lipoprotein oxidation susceptibility and increase bone density in growing pigs

The objective of this study was to determine the health benefits of extra‐virgin and refined olive oils, which are high in mono‐unsaturated fatty acids (MUFAs) and polyphenolic compounds using the pig as a model. Thirty‐two cross‐bred pigs were individually penned, allocated to one of four dietary treatments and fed ad libitum for 28 days. Two of the experimental diets consisted of a basal diet containing 12% tallow and either 7% sunflower oil (TSO) or 7% extra‐virgin olive oil (TEVO) on a w/w basis. The remaining diets contained 19% extra‐virgin olive oil (EVO) or 19% of refined olive oil (RO). On days 7, 14 and 28 fasted and 3‐h post‐prandial blood samples were taken. Body composition was measured at the beginning and end of the study using dual energy X‐ray absorptiometry. Daily gain, feed intake and lean and fat deposition were not significantly different between the treatments. However, the daily increase in bone mineral density was higher in pigs fed diets containing olive oil (1.23 vs 2.54, 6.28, 5.20 mg cm^?2 per day for TSO, TEVO, EVO and RO, respectively, P = 0.050). Both fasting and non‐fasting plasma triglycerides were lower (P = 0.003) in pigs fed MUFA‐rich diets, while the cholesterol profile was not significantly different between the treatments. The results from in vitro copper‐induced lipid peroxidation, expressed in terms of conjugated dienes, showed that low density lipoprotein (LDL) particles in postprandial serum from pigs fed olive oil were moderately more resistant to oxidative modification. In conclusion, these data demonstrate that both extra‐virgin and refined olive oils attenuate postprandial hypertriglyceridaemia, moderately affect oxidation susceptibility and increase bone mineral density in growing pigs. Copyright © 2006 Society of Chemical Industry     

Antibacterial Therapy by Ag+ Ions Complexed with Titan Yellow/Congo Red and Albumin during Anticancer Therapy of Urinary Bladder Cancer

According to the World Health Organization report, the increasing antibiotic resistance of microorganisms is one of the biggest global health problems. The percentage of bacterial strains showing multidrug resistance (MDR) to commonly used antibiotics is growing rapidly. Therefore, the search for alternative solutions to antibiotic therapy has become critical to combat this phenomenon. It is especially important as frequent and recurring infections can cause cancer. One example of this phenomenon is urinary tract infections that can contribute to the development of human urinary bladder carcinoma. This tumor is one of the most common malignant neoplasms in humans. It occurs almost three times more often in men than in women, and in terms of the number of cases, it is the fifth malignant neoplasm after prostate, lung, colon, and stomach cancer. The risk of developing the disease increases with age. Despite the improvement of its treatment methods, the current outcome in the advanced stages of this tumor is not satisfactory. Hence, there is an urgent need to introduce innovative solutions that will prove effective even in the advanced stage of the disease. In our study, a nanosystem based on ionic silver (Ag⁺) bound to a carrier—Titan yellow (TY) was analyzed. The possibility of binding the thus formed TY-Ag system to Congo red (CR) and albumin (BSA) was determined. TY-Ag binding to CR provides for better nanosystem solubility and enables its targeted intracellular transport and binding to immune complexes. The binding of TY-Ag or CR-TY-Ag to albumin also protects the system against the uncontrolled release of silver ions. It will also allow the delivery of silver in a targeted manner directly to the desired site in the case of intravenous administration of such a system. In this study, the MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) values of the TY-Ag or BSA-TY-Ag systems were determined in two reference strains (Escherichia coli and Staphylococcus aureus). The paper presents nanosystems with a size of about 40–50 nm, with an intense antibacterial effect obtained at concentrations of 0.019 mM. We have also discovered that TY-Ag free or complexed with BSA (with a minimal Ag⁺ dose of 15–20 μM) inhibited cancer cells proliferation. TY-Ag complex diminished migration and effectively inhibited the T24 cell viability and induced apoptosis. On the basis of the obtained results, it has been shown that the presented systems may have anti-inflammatory and antitumor properties at the same time. TY-Ag or BSA-TY-Ag are new potential drugs and may become in future important therapeutic compounds in human urinary bladder carcinoma treatment and/or potent antimicrobial factors as an alternative to antibiotics.