Properties of soluble and membrane intestinal hydrolases in Macaca rhesus monkeys

Evidence from several central nervous system (CNS) inflammatory disease models suggests that intrathecal complement synthesis may contribute to early inflammatory events in the brain. In this study, we examined the expression of the receptor for C5a (C5aR), a potent inflammatory and chemotactic factor, in the brains of transgenic mice with constitutive astrocyte expression of interleukin-3 (IL-3), a hematopoietic and immunomodulatory cytokine. By in situ hybridization, we demonstrated that cells infiltrating the cerebellar meninges, the cerebellum, and demyelinating lesions in the cerebellum were strongly positive for C5aR mRNA. By immunohistochemistry, the infiltrating cells expressing the C5aR were identified as macrophages based on staining with antibodies to the complement receptor type 3 and F4/80, a mouse macrophage-specific marker. In addition, some of the cells in cerebellar lesions were positive for the astrocyte-specific marker, glial fibrillary acidic protein, suggesting that a subpopulation of astrocytes in these lesions express elevated levels of the C5aR. Increased C5aR expression was also observed in cortical neurons in the occipital cortex and in pyramidal neurons in the cornu ammonis and subiculum of the hippocampus, at both the protein and mRNA levels. These data suggest that IL-3 may play an immunomodulatory role in C5aR expression on several cell types in the brain and that increased C5aR expression correlates with the pathology seen in this model. The transgenic mice used in this study provide a useful tool for characterizing the mechanism of regulation of the C5aR expression and for examining the functions of this chemotactic receptor in CNS inflammation.     

Cytotoxicity of murine B lymphocytes induced by human VH4-34 (VH4.21) gene-encoded monoclonal antibodies

We previously found that a ventricular isovolumic pressure-time curve could be well fitted by the difference between two S-shaped logistic curves for the pressure rising and falling components, and called it "hybrid logistic" function: P(t)=A/[1+exp[-(4B/A)(t-C)]]-D/[1+exp[-(4E/D)(t-F)]]+G. We reported that the parameters of this hybrid logistic function are useful to characterize left ventricular contraction and relaxation comprehensively. In this study, we investigated how well this hybrid logistic function could fit the isometric twitch force-time curves of cross-circulated right ventricular papillary muscles of 7 dogs. This function precisely fitted the isometric force curves with correlation coefficients above 0.9996, much better than another fitting function (F(t)=C(t/A)(B)exp[1-(t/A)(B)]) proposed by Nwasokwa. The present results indicate that our hybrid logistic function can also reasonably express the canine right ventricular papillary muscle isometric twitch force-time curve. We suggest the possibility that the parameters of this hybrid logistic function are also useful to comprehensively characterize right ventricular papillary muscle twitch contraction and relaxation.     

The effect of the repeated experience of aggression in daily confrontations on the individual and social behavior of male mice

The influence of repeated experience of aggression in daily intermale confrontations on individual and social behaviour was studied in male mice of C57BL/6J (C57) and CBA/Lac (CBA) strains. Repeated experience of aggression led to a decrease of emotionality in males of highly emotional CBA strain and increase in exploratory activity in the open field and exploratory activity tests, decrease of immobility time in Porsolt's test and pain sensitivity estimated by the "hot plate" test. Low emotional C57 males did not change their individual behaviour in different situations under the influence of repeated experience of aggression. However, aggressive C57 mice demonstrated anxiety-like behaviour estimated in the plus-maze test. In the partition test aggressive mice of both strains showed an increase in communicative level (as a reaction to a familiar male) in comparison with their behaviour before aggressive confrontations. Behavioural reaction to a receptive female under unfamiliar conditions decreased which testified to a decrease in sexual motivation. It is concluded that formation of the aggressive type of social behaviour is accompanied by changes in the individual and social behaviour of male mice. Characteristics of these changes are genetically determined and depend on the duration of confrontations.     

Hydrodynamic lubrication of rough slider bearings with couple stress fluids

The combined effects of couple stresses and surface roughness on the performance characteristics of hydrodynamic lubrication of slider bearings with various film shapes, such as plane slider, exponential, secant and hyperbolic, are studied. A stochastic random variable with non-zero mean, variance and skewness is used to mathematically model the surface roughness of the slider bearing’s. The Stokes couple stress fluid model is used to characterize the rheological behavior of the lubricant with polymer additives. The modified expressions for the bearing characteristics, namely pressure, load carrying capacity, center of pressure, frictional force are obtained for the general lubrication film shape on the basis of Stokes microcontinuum theory for couple stress fluids. Results are computed numerically for various film shapes under consideration. It is observed that, for all the lubricant film shapes under consideration, the negatively skewed surface roughness increases the load carrying capacity, frictional force and temperature rise, while it reduces the coefficient of friction. On the contrary, the reverse trend is observed for positively skewed surface roughness. Further, these effects are more pronounced for the couple stress fluids.     

Nanohydroxyapatite-coated hydroxyethyl cellulose/poly (vinyl) alcohol electrospun scaffolds and their cellular response

The present study focused on the preparation of nanohydroxyapatite (nHA)-coated hydroxyethyl cellulose/polyvinyl alcohol (HEC/PVA) nanofibrous scaffolds for bone tissue engineering application. The electrospun HEC/PVA scaffolds were mineralized via alternate soaking process. FESEM revealed that the nHA was formed uniformly over the nanofibers. The nHA mineralization enhanced the tensile strength and reduced the elongation at breakage of scaffolds. The wettability of the nanofibrous scaffolds was significantly improved. The in vitro biocompatibility of scaffolds was evaluated with human osteosarcoma cells. nHA-coated scaffolds had a favorable effect on the proliferation and differentiation of osteosarcoma cell and could be a potential candidate for bone regeneration.     

Influence of PCL on the material properties of collagen based biocomposites and in vitro evaluation of drug release

Formulation of biodegradable collagen–poly-?-caprolactone (PCL) based biomaterials for the sustained release of insulin is the main objective of the present work. PCL has been employed to modulate the physico-chemical behavior of collagen to control the drug release. Designed formulations were employed to statistically optimize insulin release parameter profile at different collagen to PCL molar ratios. Circular dichroism, thermoporometry, FTIR, impedance and scanning electron microscopy techniques have been employed to investigate the effect of PCL on hydration dynamics of the collagen molecule, which in turn changes the dissolution parameters of the drug from the systems. Drug entrapment efficiency has been found to be maximum for collagen to PCL molar ratio of 1:2 (> 90%). In vitro dissolution test reveals that 99% of the drug was released from composite at collagen to PCL molar ratio of 1:3 and 1:4 within 2 h, which indicates that hydrophobicity of the matrix results in weak interaction between lipophilic drug and carrier materials. The least burst release was observed for collagen to PCL molar ratio at 1:2 as synergistic interactions between collagen and PCL was maximum at that particular polymer–polymer ratios. The drug release data indicates super case-II transport of drug (n > 1.0).     

Surface immobilisation of the sandwich type Na14[Fe4(Ox)4(H2O)2(SbW9O33)2]·60H2O polyoxometalate

A functionalised Fe-substituted Keggin Na₁₄[Fe₄(C₂O₄)₄(H₂O)₂(SbW₉O₃₃)₂]·60H₂O type POM termed “Fe₄Ox₄” has been successfully immobilised onto carbon electrode surfaces through the employment of conducting polypyrrole films and the layer-by-layer (LBL) technique. For the POM doped polypyrrole films the redox systems associated with the POM's tungsten-oxo framework was not apparent upon redox cycling, however a reversible redox couple associated with the Fe^III/II redox system was clearly seen within the pH range 2–7. Organised multilayer assemblies were constructed by the employment of the layer by layer (LBL) technique through alternating anionic Fe₄Ox₄ layers and cationic Ru^II metallodendrimers with poly(diallyldimethylammonium chloride) (PDDA) employed as an initial base layer. Stable redox couples associated with both the Fe^III/II and tungsten-oxo framework, for the Fe₄Ox₄ POM, and the Ru^III/II for the metallodendrimer, were clearly observed upon layer construction and redox switching within the pH domain of 2–7. The resulting multilayer assembly showed good stability towards redox cycling. Further investigations into the multilayer assembly were undertaken by determining it is charge transfer resistance using AC-impedance voltammetry. The layer also showed catalytic ability towards the reduction of H₂O₂ at pH 6.5.     

A facile spin-cast route for cation exchange of multilayer perpendicularly-aligned nanorod assemblies

A facile spin cast route was developed to convert perpendicularly aligned nanorod assemblies of cadmium chalcogenides into their silver and copper analogues. The assemblies are rapidly cation exchanged without affecting either the individual rod dimensions or collective superlattice order extending over several multilayers.     

A novel water‐soluble,conducting polymer composite for mild steel acid corrosion inhibition

A novel water‐soluble conducting polymer composite, poly(vinyl alcohol‐histidine) was synthesized from aqueous solution by free radical condensation using persulfate. The composite was characterized using UV–Visible, Fourier transform infrared, scanning electron microscopy, thermogravimetric analysis (TG/DTG), and differential scanning calorimetry techniques while its AC conductance was measured by LCZ analyzer. The inhibitive action of the composite on the corrosion behavior of mild steel in 1M HCl was studied by conventional weight loss method, potentiodynamic polarization studies (Tafel), linear polarization studies, and electrochemical impedance spectroscopy. The effects of inhibitor concentrations, exposure time, and temperature have been investigated. The corrosion rate, inhibition efficiency (IE), and other parameters have been evaluated for different inhibitor concentrations. The composite provided more than 95% IE at an optimum concentration of 0.6% by weight. The results showed the composite as an effective mixed type inhibitor. The adsorption of this inhibitor obeyed Temkin adsorption isotherm. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013