Two phase micromixing and analysis using electrohydrodynamic instabilities

Organic–aqueous liquid (phenol) extraction is one of many standard techniques to efficiently purify DNA directly from cells. Effective mixing of the two fluid phases increases the surface area over which biological component partitioning may occur. In this work, two phase mixing has been demonstrated in a three inlet microfluidic device geometry. Mixing between the two phases has been achieved by producing an electrohydrodynamic instability at the liquid–liquid interface between the two phases. The initial instability is modeled by considering the small signal linearized analysis for interfacial stresses from both fluid and electrical stress tensors for both inviscid and viscous models. These models predict the onset of instability and the stability criteria over a range of unstable wavenumbers of the mixing process. These models may be applied to relevant microscale geometries, where the unstable wavenumbers and fastest growth wavenumber are determined. At an applied electric field of ∼8.0×10⁵ V/m an instability is experimentally observed by labeling the organic phase with a fluorescent dye and visualizing interfacial perturbations by microscopy. Increasing the electric field increases the instability growth rate and results in an increase of the level of mixing. These results show an increase in conductive fluid entrainment into the nonconducting fluid core measured as a percentage of area of entrainment into the fluorescently labeled organic phase. The entrainment area is seen to increase from 1.9 to 28.6% as the applied field is increased from 8.0×10⁵ to 9.0×10⁵ V/m. The mixing images are converted into a power spectrum using a fast Hartley transform and the band of unstable wavenumbers of the mixing process are determined. From these results, the theoretical field strengths required to produce these unstable wavenumbers are calculated using the theoretical model, determining the maximum field strength required to excite the largest measured unstable wavenumber. At lower field strengths tested, the theoretically predicted maximum electric field and fastest growth wavenumber compare favorably with the initially applied field and measured fastest growth wavenumber whereas at higher field strengths the theoretical field is much larger than the initially applied field. This is attributed to the larger level of mixing and the ability of the instability to grow beyond the linear range and the field increases as the mixing process occurs due to entrainment of highly conductive fluid decreasing the effective dielectric spacing so that the linearized models underpredict the instability growth rates and interfacial perturbations.     

Cross-national differences in consumer responses to savoury crackers containing blackcurrant pomace

Juice-pressing residues, among them blackcurrant pomace, are valuable materials for being upgraded in food products. Their excellent nutritional profiles in line with their functional properties allow a wide range of applications. The current study was performed to evaluate the overall liking of a pomace-enriched thin crispy-baked bread product in five European countries, and to obtain suggestions for improvements. Moreover, data on the frequency of snack consumption, openness to new foods and an opinion on residues in food applications were acquired. Four hundred and sixty-six consumers from United Kingdom, Spain, Sweden, Italy and Germany were involved. On a 9-point hedonic scale, the pomace cracker was rated towards the direction of liking with 5.94 ± 1.90 on average. Contingency tables showed that the overall-liking correlated highly significant (p < 0.01) with the country of origin and sex of the respondents and their openness to new products. Significantly higher liking scores were provided by British and Spanish consumers and, among these respondents, savoury snacks were stated to be consumed most frequently. Therefore, the snack consumption frequency also appeared to be a driver for cross-national differences in hedonic responses. The consent for using pomace in food products was remarkably high (>90%) in all countries and stresses consumer awareness in terms of healthy longevity and sustainability.     

The POLARBEAR-2 Experiment

We present an overview of the design and development of the POLARBEAR-2 experiment. The POLARBEAR-2 experiment is a cosmic microwave background polarimetry experiment, which aims to characterize the small angular scale B-mode signal due to gravitational lensing and search for the large angular scale B-mode signal from inflationary gravitational waves. The experiment will have a 365 mm diameter multi-chroic focal plane filled with 7,588 polarization sensitive antenna-coupled Transition Edge Sensor bolometers and will observe at 95 and 150 GHz. The focal plane is cooled to 250 mK. The bolometers will be read-out by SQUIDs with \(32\times \) frequency domain multiplexing. The experiment will utilize high purity alumina lenses and thermal filters to achieve the required high optical throughput. A continuously rotating, cooled half-wave plate will be used to give stringent control over systematic errors. The experiment is designed to achieve a noise equivalent temperature of 5.7  \(\mu \) K \(\sqrt{s}\) , and this allows us to constrain the signal from the inflationary primordial gravitational corresponding to a tensor-to-scalar ratio of \(r = 0.01\) ( \(2\sigma \) ). POLARBEAR-2 will also be able to put a constraint on the sum of neutrino masses to 90 meV ( \(1\sigma \) ) with POLARBEAR-2 data alone and 65 meV ( \(1\sigma \) ) when combined with the Planck satellite. We plan to start observations in 2014 in the Atacama Desert in Chile.     

OVPD und Anwendung optischer Spektroskopiemethoden zur Wachstumskontrolle. OVPD and Applications of Optical Spectroscopic Methods to Growth Control

Organic Vapor Phase Deposition (OVPD) is a new thin film growth technique which is very suitable for deposition of uniform thin films on larger substrate areas. The polarization sensitive methods, ellipsometry and Reflectance Anisotropy Spectroscopy (RAS), have huge potential for the control of the growth in the OVPD process. The capability of ellipsometry to determine the thickness and the optical constants of OVPD deposited films was demonstrated using as example an Alq₃ film. RAS showed high potential for the detection of very thin organic anisotropic films, as exemplified for an PTCDA film.     

Microglial phagocytosis is modulated by pro- and anti-inflammatory cytokines

Activation of microglial cells in neurological diseases involves proliferation and the induction of phagocytic and cytotoxic properties. We studied the effects of four different cytokines on microglial phagocytosis of latex beads to gain further insights into the signals modulating different aspects of microglial activity. Granulocyte/macrophage colony stimulating factor and tumor necrosis factor-alpha enhanced microglial phagocytic activity as measured by flow cytometry. A phagocytosis inhibiting effect was observed after preincubation with transforming growth factor-beta1 and interleukin-4. In conclusion, the activating and deactivating cytokines differentially regulate microglial phagocytic activity in vitro and might also play an important role in vivo in modulating microglial activation to keep the balance between the protective, defensive and destructive, chronic inflammatory properties of microglia.     

Cytochrome P460 genes from the methanotroph Methylococcus capsulatus bath

P460 cytochromes catalyze the oxidation of hydroxylamine to nitrite. They have been isolated from the ammonia-oxidizing bacterium Nitrosomonas europaea (R. H. Erickson and A. B. Hooper, Biochim. Biophys. Acta 275:231-244, 1972) and the methane-oxidizing bacterium Methylococcus capsulatus Bath (J. A. Zahn et al., J. Bacteriol. 176:5879-5887, 1994). A degenerate oligonucleotide probe was synthesized based on the N-terminal amino acid sequence of cytochrome P460 and used to identify a DNA fragment from M. capsulatus Bath that contains cyp, the gene encoding cytochrome P460. cyp is part of a gene cluster that contains three open reading frames (ORFs), the first predicted to encode a 59,000-Da membrane-bound polypeptide, the second predicted to encode a 12, 000-Da periplasmic protein, and the third (cyp) encoding cytochrome P460. The products of the first two ORFs have no apparent similarity to any proteins in the GenBank database. The overall sequence similarity of the P460 cytochromes from M. capsulatus Bath and N. europaea was low (24.3% of residues identical), although short regions of conserved residues are present in the two proteins. Both cytochromes have a C-terminal, c-heme binding motif (CXXCH) and a conserved lysine residue (K61) that may provide an additional covalent cross-link to the heme (D. M. Arciero and A. B. Hooper, FEBS Lett. 410:457-460, 1997). Gene probing using cyp indicated that a cytochrome P460 similar to that from M. capsulatus Bath may be present in the type II methanotrophs Methylosinus trichosporium OB3b and Methylocystis parvus OBBP but not in the type I methanotrophs Methylobacter marinus A45, Methylomicrobium albus BG8, and Methylomonas sp. strains MN and MM2. Immunoblot analysis with antibodies against cytochrome P460 from M. capsulatus Bath indicated that the expression level of cytochrome P460 was not affected either by expression of the two different methane monooxygenases or by addition of ammonia to the culture medium.     

Prediction of total body lipid from total body water in rats. Part 1. Relations between directly measured major body components.

Aimed to the construction of a prediction equation for estimations of lipid content from animal water content body composition was determined by whole body analysis of male rats (1) given access, ad libitum, to a commercial standard diet (n = 144; ranging from 60 to 600 g in weight, and from the 4th to the 34th week of age), and (2) showing striking variations with regard to nutritional state, dietary history, enlarged fat deposition, genetic origin, intestinal microbial status, and advanced age (n = 75). It was shown that a unique coefficient of water content in lipid-free body mass does not exist. The results of statistical analysis for the grouped values of percentage body dry matter (x) and percentage body lipid (y) indicate that the latter can be estimated accurately from body water content directly determined by the use of the quadratic regression equation y = -0.2864 x +0.01615 x2 with a standard deviation of the procedure Sy = +/- 1.40. This prediction equation is valid for a wide developmental span even under highly different experimental states. Differences between the calculated body lipid contents vs. analytically determined values are smaller than by using a linear regression equation or coefficient(s) of hydration of lipid-free body mass.     

Effect of enzymatic meat tenderizers]

Tenderizing preparations which are applied intramuscularly or via the blood vessels spread throughout the endomysium and the perimysium and produce there their effects (especially on the collagenous portion of the connective tissue) during cooking in certain ranges of temperature. Sarcoplasmic proteins are also attacked, whereas myofibrillary proteins are not affected. Consequently, in contrast to natural meat ageing, only the collagen-induced background toughness is actually eliminated, and the actomyosin-induced toughness is influenced only in so far as the degradation of the connective tissue causes a general structural loosening of the meat.