Impact of Milk Protein Type on the Viability and Storage Stability of Microencapsulated Lactobacillus acidophilus NCIMB 701748 Using Spray Drying

Three different milk proteins — skim milk powder (SMP), sodium caseinate (SC) and whey protein concentrate (WPC) — were tested for their ability to stabilize microencapsulated L. acidophilus produced using spray drying. Maltodextrin (MD) was used as the primary wall material in all samples, milk protein as the secondary wall material (7:3 MD/milk protein ratio) and the simple sugars, d-glucose and trehalose were used as tertiary wall materials (8:2:2 MD/protein/sugar ratio) combinations of all wall materials were tested for their ability to enhance the microbial and techno-functional stability of microencapsulated powders. Of the optional secondary wall materials, WPC improved L. acidophilus viability, up to 70 % during drying; SMP enhanced stability by up to 59 % and SC up to 6 %. Lactose and whey protein content enhanced thermoprotection; this is possibly due to their ability to depress the glass transition and melting temperatures and to release antioxidants. The resultant L. acidophilus powders were stored for 90 days at 4 °C, 25 °C and 35 °C and the loss of viability calculated. The highest survival rates were obtained at 4 °C, inactivation rates for storage were dependent on the carrier wall material and the SMP/d-glucose powders had the lowest inactivation rates (0.013 day^?1) whilst the highest was observed for the control containing only MD (0.041 day^?1) and the SC-based system (0.030 day^?1). Further increase in storage temperature (25 °C and 35 °C) was accompanied by increase of the inactivation rates of L. acidophilus that followed Arrhenius kinetics. In general, SMP-based formulations exhibited the highest temperature dependency whilst WPC the lowest. d-Glucose addition improved the storage stability of the probiotic powders although it was accompanied by an increase of the residual moisture, water activity and hygroscopicity, and a reduction of the glass transition temperature in the tested systems.     

In vitro differentiation of a cloned bovine mammary epithelial cell

The aim of the study was to establish in vitro a bovine mammary epithelial cell (MEC) clone, able to respond to mitogenic growth factors and to lactogenic hormones. Mammary tissue from a 200-d pregnant Holstein cow was used as a source of MEC, from which a clone was established through a process of limiting dilution. When plated on plastic, the cells assumed a monolayer, cobblestone, epithelial-like morphology, with close contact between cells. Inclusion of IGF-1 and EGF in the media significantly increased the number of cells 5 d after plating. All cells stained strongly for cytokeratin and moderately for vimentin at young and old passage stages, indicating the epithelial nature of this cell clone. When the cells were plated at a high density on a thin layer of a commercial extracellular matrix preparation (Matrigel), lobular, alveoli-like structures developed within approximately 5 d, with a clearly visible lumen. When cells were plated onto Matrigel in differentiation media (containing lactogenic hormones), detectable quantities of alpha-casein were present in the media and particularly on the lumen side of the structures. Omission of one of the lactogenic hormones (insulin, prolactin or hydrocortisone) reduced alpha-casein release to the limit of detection of the assay used. Lactoferrin was also produced when the cells were plated on Matrigel, again principally on the lumen side of the lobules, though this was independent of the lactogenic hormones. By passage 40, the cells had senesced, and it was not possible to induce alpha-casein or lactoferrin production. This study notes the establishment of a functional bovine mammary epithelial cell clone, which is responsive to mitogenic and lactogenic hormones and an extracellular matrix.     

Hybrid White Light Emitting Diode Based on Silicon Nanocrystals

A novel design of white light emitting diodes (WLEDs) emerges to meet the growing global demand for resource sustainability while preserving health and environment. To achieve this goal, a facile method is developed for the chemical synthesis of a luminescent silicon nanocrystal (ncSi) with a large Stokes shift between absorption and emission. The WLED is prepared by a simple spin‐coating method, and contains a hybrid‐bilayer of the ncSi and luminescent polymer in its device active region. Interestingly, a well‐controlled ultrathin ncSi layer on the polymer makes possible to recombine electrons and holes in both layers, respectively. Combining red and blue‐green lights, emitted from the ncSi and the polymer layers, respectively, produces the emission of white electroluminescence. Herein, a hybrid‐WLED with a sufficiently low turn‐on voltage (3.5 V), produced by taking advantages of the large Stokes shift inherent in ncSi, is demonstrated.     

Phase separation mechanism during membrane formation by dry‐cast process

Phase separation mechanisms during the membrane formation by dry‐cast process were investigated by light scattering in the cellulose acetate/dimethylformamide (DMF)/2‐methyl‐2,4‐pentanediol system. Phase separation occurred by spinodal decomposition (SD) when paths of the composition changes due to the evaporation of DMF were close to the critical point in the phase diagram. Characteristic properties of the early stage of SD such as an apparent diffusion coefficient and an interface periodic distance were obtained from the Cahn theory. Phase separation occurred by nucleation and growth (NG) when paths of the composition changes were far from the critical point. SEM observation confirmed that the membrane formed by the SD mechanism had interconnected structure, whereas that by the NG mechanism had the closed cell porous structure. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 776–782, 2000     

Effect of the addition of the surfactant Tetronic 1307 on poly(ether sulfone) porous hollow-fiber membrane formation

Poly(ether sulfone) (PES) hollow-fiber membrane was prepared via a nonsolvent-induced phase-separation method, and the effect of the addition of the surfactant Tetronic 1307 on the membrane performance and characteristics was investigated. The phase diagram of the PES/N-methyl-2-pyrrolidone (NMP)/water system was clarified. When the polymer solution involved Tetronic 1307, the amount of water required to induce the phase separation decreased, which indicated that Tetronic 1307 was one kind of nonsolvent. The kinetics of phase separation for the PES/NMP/Tetronic 1307 system were studied by light-scattering measurements. With the addition of Tetronic 1307, delayed phase separation was observed, and the structure growth rate decreased. Scanning electron microscopy images for all of the membranes showed the formation of fingerlike macrovoids through the cross section. Membrane surface morphologies were measured by atomic force microscopy. The obtained results indicated that membrane with 7 wt % Tetronic 1307 had higher roughness parameters than original membrane without the addition of surfactant. Ultrafiltration experiment results showed that the addition of Tetronic 1307 brought about an increase in water permeability and decreased the rejection of dextran with a molecular weight of about 10,000. The contact angles of water on the membrane outer surface decreased with the addition of Tetronic 1307. This mean the membrane surface became more hydrophilic. Thus, the addition of Tetronic 1307 was useful for improving the water permeability and for obtaining a hydrophilic membrane surface. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Application of a dispersed autonomous voltage control system to a real high‐voltage distribution network

This paper focuses on the application results of the dispersed autonomous voltage control system, which the authors have proposed, to a real distribution network. This system is effective for regulating the supply voltage of an entire HV line within an optimum range. In the system configuration, an SCC is installed together with an SC and/or ShR on the line. Individual SCCs autonomously control the operation of SCs and/or ShRs based on the voltage measured where the SCs and/or ShRs are located on the line. A field test on a real high‐voltage distribution network found that the proposed system could sustain a high fault tolerance ability and also be cost‐effective in regulating line voltage. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(1): 27–36, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10252     

Development of a digital real‐time simulator for power electronics systems

A digital real‐time simulator for power electronics systems has been developed using MATLAB^TM/SIMULINK^TM. This paper describes the modeling and calculation accuracy of static synchronous compensator (STATCOM) models. Since the simulator operates in a large time step of 50 µs, compensation processing is implemented with the STATCOM model to improve the simulation accuracy. The calculation result of the real‐time STATCOM model is the same as that of non‐real‐time PSCAD^TM/EMTDC^TM. Stable operation of the newly developed simulator was successfully confirmed when connected to a commercial real‐time digital simulator (RTDS^TM). © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 148(4): 41–49, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10321     

DEPOSITION OF AEROSOL PARTICLES ON A SURFACE COMPOSED OF DIFFERENT TYPES OF MATERIALS

Experimental and theoretical studies have been conducted on the deposition of aerosol particles on a surface composed of different types of materials (copper-polyethylene and copper-nickel). Deposition of charged particles is affected by localized electrostatic fields created by the contact potential difference between the different types of materials. The particles charged with positive polarity deposit mainly on the polyethylene or the nickel surfaces, which are negatively charged. The deposition profile has been also controlled by varying the thickness of gold layers deposited on nickel surface.     

Compositions and Microstructures of the Primary Ceramic Materials in the Paleolithic Age Through XRD, SEM, and TEM Analyses

The mineral compositions and microstructures of Paleolithic materials were first investigated by X-ray diffraction analysis, scanning electron microscopy, and transmission electron microscopy in order to understand the primary ceramic material in human history. Shale and chalcedony artifacts excavated from upper Paleolithic sites were analyzed. As a result, from among various candidates with nonuniform mineral compositions, only limited materials containing polycrystals with approximately more than 95%α-quartz content were selected as tool materials. Moreover, every Paleolithic material invariably exhibited densely packed and homogeneous micrograins approximately 0.1–0.5 μm in size and an equigranular structure with few porosities at the grain boundaries.     

Effect of blade rotation on particle classification performance of hydro-cyclones

The effects of top blade rotation of hydro-cyclones on particle classification performance were examined experimentally and via a simulation study.It was noticed that the cut size of a hydro-cyclone decreases as the rotational speed of the top plate increases. Compared to the standard case without rotation, the accuracy of classification with top plate rotation increases under the wide range of operational conditions.Newly proposed type-D cyclones with a special blade indicated the smallest cut size with a high accuracy of classification. The increase of classification accuracy is due to the production of outward radial flow near the top plate and this result was simulated by a CFD calculation.The computer simulation also agreed qualitatively with the experimental data.