Cationic liposome-DNA complexes: from liquid crystal science to gene delivery applications

At present, there is an unprecedented level of interest in the properties and structures of complexes consisting of DNA mixed with oppositely charged cationic liposomes (CLs). The interest arises because the complexes mimic natural viruses as chemical carriers of DNA into cells in worldwide human gene therapy clinical trials. However, since our understanding of the mechanisms of action of CL-DNA complexes interacting with cells remains poor, significant additional insights and discoveries will be required before the development of efficient chemical carriers suitable for long-term therapeutic applications. Recent studies describe synchrotron X-ray diffraction, which has revealed the liquid crystalline nature of CL-DNA complexes, and three-dimensional laser-scanning confocal microscopy, which reveals CL-DNA pathways and interactions with cells. The importance of the liquid crystalline structures in biological function is revealed in the application of these modern techniques in combination with functional transfection efficiency measurements, which shows that the mechanism of gene release from complexes in the cell cytoplasm is dependent on their precise liquid crystalline nature and the physical and chemical parameters (for example, the membrane charge density) of the complexes. In [section sign] 5, we describe some recent new results aimed at developing bionanotube vectors for gene delivery.     

Urinary oestradiol and testosterone levels from novel male mice approach values sufficient to disrupt early pregnancy in nearby inseminated females

Previous research has established that exposure to novel male mice can disrupt intrauterine implantation of fertilised ova in inseminated females and that much of this effect is mediated by factors in the male urine. The present studies were designed to examine whether the steroid content of male urine is sufficient to account for this effect. Pregnancy was terminated by exogenous 17beta-oestradiol administered intranasally on days 2-4 after insemination in doses as low as 0.14 microg/day. Enzyme immunoassay indicated that male mouse urine reliably contains unconjugated 17beta-oestradiol and testosterone. A small but significant increase in the amount of urinary oestradiol was observed in males housed nearby previously inseminated females as opposed to those housed in isolation. This influence was absent in the sire and absent in novel males when the sire was also present. The quantity of active steroids in novel male urine approaches the level sufficient to account for the disruption of implantation in nearby inseminated females.     

Nanoparticle surface as activation site

The immense surface-to-volume (S/V) ratio in nanoparticles leads to large surface energy density. These high densities play the role of sites for activities that are not triggered in bulk materials. Here we present some examples of such distinctive activities taking place at nanoparticle surfaces. Our first example involves the morphological changes in silkworm (Bombyx mori L.) nuclear polyhedrosis virus (BmNPV) brought about by lipophilic amorphous silica nanoparticles (LASN). Microscopy studies show that nanoparticles severely alter the structure of the virus envelope by a 'deflation' of the viral polyhedron and formation of elongated structures. The second example shows the spatial variation in aggregation potential with temperature, for dodecanethiol-capped Au nanoparticles on an amorphous polystyrene film surface. We find that on increasing the temperature from 32 degrees C to 50 degrees C the aggregating potential becomes almost completely confined to the film surface, whereas going over to 100 degrees C the confining potential is overcome and out-of-plane growth takes place. A tentative and qualitative explanation has been attempted.     

Second Stage Gas Turbine Blade Premature Replacement Investigation

This article investigates the root causes of the premature failure and replacement of a set of second-stage turbine blades from a heavy industrial gas turbine engine. The investigations included dye-penetrant testing, optical microscopy, X-ray diffractometry (XRD), Environmental Scanning Electron Microscopy (ESEM), and energy dispersive X-ray spectroscopy (EDS) techniques. Moreover, the effect of heat treatment process on restoring the blade microstructure so that the properties were suitable for service was also explored. As a result of the investigation, the second-stage turbine blades premature failure was attributed to the grain boundary secondary phase precipitates. These precipitates were present in the “as-found” condition of the investigated blades.     

Health-promoting benefits of low-fat akawi cheese made by exopolysaccharide-producing probiotic Lactobacillus plantarum isolated from camel milk

Lactic acid bacteria isolated from camel milk exhibit remarkable probiotic and exopolysaccharide (EPS)-producing characteristics. The health-promoting benefits of exopolysaccharide-producing probiotic Lactobacillus plantarum isolated from camel milk used for making low-fat akawi cheese were investigated. Three low-fat akawi cheeses were made using traditional culture (non-EPS-producing, EPS^?), commercial EPS-producing (MEPS⁺), and camel milk EPS-producing (CEPS⁺) cultures. α-Amylase and α-glucosidase inhibitory activities, antioxidant activities, angiotensin-converting enzyme (ACE) inhibition, and antiproliferative activity were determined. Cheese made with CEPS⁺ culture exhibited comparable α-amylase inhibition to that of cheeses made with MEPS⁺. Scavenging rates of cheese made with EPS⁺ cultures were higher than those of cheese made with EPS^? cultures. The percentage of α-glucosidase inhibition ranged from >45% at 0 d to ～55% at 21 d of storage. After 7 d of storage, the scavenging rate in CEPS⁺ cheese increased >60% by ABTS assay [2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid)] and >20% by DPPH assay (1,1-diphenyl-2-picrylhydrazyl). Throughout storage, cheese made with EPS⁺ cultures showed higher ACE-inhibition activity compared with EPS^? cultures. Cheese made with CEPS⁺ showed ACE inhibition >70% after 7 d of storage. Antiproliferation activity of CEPS⁺ cheese increased from 38 to 48% during 7 d of storage and was maintained above 45% with prolonged storage. Low-fat akawi cheese produced with these cultures exhibited similar or greater health-promoting benefits compared with cheese made using commercial starter cultures. Therefore, incorporation of these cultures in food is promising for commercial uses.     

Manufacturing features: Verification interaction accessibility and machinability

A major problem in CAD/CAM integration lies in the difficulty in representing the component definition adequately for all applications. Features are considered as a main factor in the CAD and CAM link because various design, engineering and manufacturing data can be associated with a feature. However, tagging feature labels onto geometry does not guarantee the geometric correctness of the resultant feature; knowledge of the topology and analysis of the geometry is needed to correctly identify the validity of the resultant feature. This paper discusses a feature-based design system capable of representing 2.5D components in terms of manufacturing features such as holes, slots and pockets, which are associated with distinctive manufacturing processes. The system is capable of verifying all the defined features by comparing the definition of the resultant features against those of the applied features. Feature interactions are considered to investigate the effect of the interaction on the validity, accessibility and machinability of each feature. Individual features can be extracted from the product model, where all the information about the product is held, for analyses. Each volumetric feature corresponds to a solid that can be removed by one or more machining operations; as a consequence of applying volumetric features, surface features are generated. These surface features provide enough information to enable the validity and machinability of the individual features to be determined and to establish the possible routes in which the feature can be accessed, if any. The proposed approach has been explored in a rapid prototyping test bed consisting of product modelling environment coupled with a solid modeller.     

Optimization of Cutting Parameters in Face Milling with Neural Networks and Taguchi based on Cutting Force,Surface Roughness and Temperatures

Prediction of cutting parameters as a function of cutting force, surface roughness and cutting temperature is very important in face milling operations. In the present study, the effect of cutting parameters on the mentioned responses were investigated by using artificial neural networks (ANN) which were trained by using experimental results obtained from Taguchi’s L8 orthogonal design. The experimental results are compared with the results predicted by ANN and the Taguchi method. By training the ANN with the results of experiments which are corresponding with the Taguchi L8 design, with only eight experiments an effective ANN model is trained. By using this network model the other combinations of experiments which did not perform previously, could be predicted with acceptable error.     

Obtaining Butter Oil Triacylglycerols Free from β-Carotene and α-Tocopherol via Activated Carbon Adsorption and Alumina-Column Chromatography Treatments

It is difficult to remove β-carotene from oils with alumina-column chromatography, because β-carotene is even less-polar than triacylglycerols (TAGs) are. The objective of this study was to obtain butter oil TAGs free from β-carotene and antioxidants via sequential treatments with activated carbon (AC) adsorption and alumina column chromatography. The AC used was prepared from waste apricots. The effects of AC dosages, temperatures and time courses on β-carotene adsorption were studied. The Langmuir and Freundlich isotherms were used to describe the adsorption of β-carotene onto AC, and it was found to be more consistent with the Freundlich isotherm with a higher R ² value (0.9784). Adsorption kinetics of β-carotene was analyzed by pseudo-first order and pseudo-second order models. The pseudo-second order model was found to explain the kinetics of β-carotene adsorption more effectively (R ² = 0.9882). The highest β-carotene reduction was achieved (from 31.9 to 1.84 mg/kg) at an AC dosage of 10 wt%, temperature of 50 °C, and adsorption time of 240 min. A considerable amount of α-tocopherol was also adsorbed during the AC treatment. Remaining portions of α-tocopherol were completely removed with alumina adsorption chromatography. The method described may be used for purification of vegetable oil TAGs, which will be used as model compounds in model oxidation studies.     

SPME-GC-MS detection of volatile compounds in apricot varieties

Aroma compounds of the eight Malatya apricot cultivars, six cultivars grown in the same breeding conditions from different locations and one hybrid cultivar were determined using SPME-GC-MS technique. In general, total concentration (sum of identified and unidentified peaks) of aroma compounds in Malatya apricot cultivars were lower than those others. Total concentration of aroma compounds were found to be in the range of 514 and 6232 μg/kg fresh weight. The main volatiles of apricot cultivars were aldehydes, alcohols, acetates, esters, terpenes and acids. Among these compounds; ethanol, hexanal, hexyl acetate, (Z)-3-hexenyl acetate, (E)-2-hexenyl acetate, 1-hexanol, (Z)-3-hexenol and (E)-2-hexen-1-ol, were present in all cultivars studied at certain levels.     

Primary and Secondary Proteolysis in Eleven Turkish Cheese Varieties

Levels of proteolysis of 75 samples belonging to 11 Turkish cheese varieties, including Civil, Canak, Dil, Divle Tulum, Ezine, Hellim, Malatya, Mihalic, Orgu, Urfa, and Van Otlu, were comparatively studied. The cheeses were mainly produced using traditional methods; however, some varieties were industrially produced. Chemical composition and the levels of soluble nitrogen fractions of the cheeses varied depending on the cheese variety. Gel electrophoresis of the cheeses showed that the samples presented different gel patterns with α_s1-casein being extensively degraded in many cheeses; whereas the hydrolysis of α_s1-casein in Malatya and Hellim was observed to be limited. Peptide profiles by RP-HPLC of the water-soluble fractions were largely different for many of the samples, but some similarities were visualized. Multivariate analysis of the RP-HPLC data grouped the cheeses according to their peptide profiles. The results suggested that each variety of cheese had different levels of proteolysis. The manufacturing technique and ripening conditions employed have played a determinative role on the proteolytic patterns of the cheeses analyzed.