Influence of high pressure homogenization and pulp reduction on residual pectinmethylesterase activity,cloud stability and acceptability of Lane Late orange juice: A study to obtain high quality orange juice with extended shelf life

Lane Late orange juice with extended shelf life (3 months at 3 °C) was obtained by high pressure homogenization (HPH) at 150 MPa at 68 °C for 15 s. Residual pectinmethylesterase (PME) inactivation level achieved was 75% but its cloudiness was maintained during storage and its acceptability undistinguishable from that of fresh juice during the assayed period. Juices with entire and reduced (50% and 25%) pulp contents were also homogenized at 150 MPa at different temperatures (63 °C and 58 °C for 15 s) to establish an appropriate shelf life of orange juices according to a desired level of cloudiness. Results showed how cloud stability of pulp reduced samples, even with a residual PME inactivation level above 90%, was not satisfactory (as in the case of entire juices homogenized out of 68 °C). The proposed methodology can easily be implanted by citrus industry to obtain high quality chilled orange juices with prolonged shelf life.     

Virtual Teams and the Importance of Building Trust

Trust in the workplace is both an ethical and a management issue. Virtual teams have become common in IT, but the importance of building trust in such teams is often underappreciated. In this installment of IT Ethics, the authors look at several definitions and theories of trust and their application in virtual IT teams.     

Evaluation of mass absorption in LiBr flat-fan sheets

Experiments were conducted to determine the absorption rates of refrigerant vapour in an aqueous lithium bromide flat-fan sheet for use in absorption air-conditioning systems. The solution flow rates tested ranged from 0.023 to 0.054 kg/s (84–194 kg/h), with pressure losses in the injection nozzle of from 40 to 250 kPa. The effect of the mass flow rate on both solution residence time and the sheet deformation rate was also analyzed in absorption chambers of a pre-defined length, along with the effect of the sub-cooling temperature on the amount of vapour absorbed. The downstream evolution of approach to equilibrium factor F was quantified. The mass transfer coefficient values were found to be over 3 × 10⁻⁴ m/s. In absorption chambers 100 mm long, over 0.8 g/s l of vapour were absorbed per chamber absorption volume. Moreover, about 600 g of vapour were absorbed per kJ of solution flow work. Flat-fan sheet configurations were found to perform better than falling film and spray absorbers.     

Fluid flow modeling in a sulfonated cation‐exchange membrane

Liquid permeation measurements of water, methanol, and 2‐propanol were carried out using a commercial cation‐exchange membrane Nafion‐117 (perfluorinated polyethylene with pendant ether‐linked side chains terminated with sulfonated groups). The experimental permeation data are treated and analyzed using the capillary model, leading to the determination of equivalent pore radius of the membrane structure. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and Antimalarial Properties of Streptocyanine Dyes

Several streptocyanine dyes were synthesized that contain polymethine chains of varying length. Their in vitro antimalarial activities were evaluated against the virulent P. falciparum parasite. In addition to the influence of polymethine chain length, the effects of structural modifications at nitrogen end groups, para substitution of the phenyl groups, and counter‐anions were studied. The most potent antimalarial activities were found for heptacarbon chain streptocyanines, with an IC₅₀ value of 60 nM . Interestingly, most of the compounds were less cytotoxic toward the mammalian cells tested. The best selective toxicity profiles were found for pentacarbon chain streptocyanines, which have a good in vitro specificity index.     

A comparison of variate pre-selection methods for use in partial least squares regression: A case study on NIR spectroscopy applied to monitoring beer fermentation

This work investigates four methods of selecting variates from near-infrared (NIR) spectra for use in partial least squares (PLS) regression models to predict biomass and chemical changes during beer fermentation. The fermentation parameters studied were ethanol concentration, specific gravity (SG), optical density (OD) and dry cell weight (DCW). The four selection methods investigated were: Simple, where a fingerprint region is chosen manually; CovProc, a covariance procedure where variates are introduced based on the magnitude of the first PLS vector coefficients; CovProc–SavGo, a modification to CovProc where the window size of a Savitzky-Golay filter applied to the spectra is also optimised; and genetic algorithm (GA), where variates are selected based on the frequency of appearance in 8-variate multiple linear regression models found from repeated execution of the GA routine. The analysis found that all four methods produced good predictive models. The GA approach produced the lowest standard error in prediction (SEP) based on leave-one-out cross-validation (LOO-CV), although this advantage was not reflected in the standard error in validation values, SEV, where all four models performed comparably. From this work, we would recommend using the Simple approach if a suitable fingerprint region can be identified, and using CovProc otherwise.     

Micropallet arrays for the separation of single, adherent cells

The selection and collection of single cells from within a heterogeneous population is required to produce genetically engineered cell lines, to develop new stem cell lines, and for single-cell studies. We describe a new platform for the positive selection of single live mammalian cells while the cells remain adherent to their growth surface. Cells were grown on arrays of microfabricated, releasable elements composed of SU-8 polymer termed "cell pallets". The presence of air between the elements restricted the cells to the top surfaces of the pallets. Single pallets situated within large arrays of pallets were released on demand using a single, focused, laser pulse. The laser pulses were low in energy (2-5 muJ) and did not detach nearby, nontargeted pallets. Since the SU-8 pallets and the underlying glass substrate were optically transparent, the cells on the pallets could be visualized by microscopy before and after release. Over 90% of cells remained attached to the pallet during laser-based release. The feasibility of growing the cells from the released pallets into clonal colonies was demonstrated. The pallet array system permits adherent cells to be inspected using conventional microscopy and selected cells released for further analysis. The ability to assess cells while they remain adherent to a surface will broaden the number of attributes that can be utilized for cell separation, for example, cell shape, cytoskeletal properties, and other attributes.     

Rapid annealing of reactively sputtered precursors for Cu2ZnSnS4 solar cells

Cu₂ZnSnS₄ (CZTS) is a promising thin‐film absorber material that presents some interesting challenges in fabrication when compared with Cu(In,Ga)Se₂. We introduce a two‐step process for fabrication of CZTS films, involving reactive sputtering of a Cu‐Zn‐Sn‐S precursor followed by rapid annealing. X‐ray diffraction and Raman measurements of the sputtered precursor suggest that it is in a disordered, metastable CZTS phase, similar to the high‐temperature cubic modification reported for CZTS. A few minutes of annealing at 550 °C are sufficient to produce crystalline CZTS films with grain sizes in the micrometer range. The first reported device using this approach has an AM1.5 efficiency of 4.6%, with J_sc and V_oc both appearing to be limited by interface recombination. Copyright © 2012 John Wiley & Sons, Ltd.