Protoplast from <Emphasis Type="Italic">β</Emphasis>-carotene-producing fungus <Emphasis Type="Italic">Blakeslea trispora</Emphasis>: Preparation,regeneration and validation

The effects of key parameters on the preparation and regeneration of protoplast from the β-carotene-producing fungus Blakeslea trispora were discussed in this paper, including the combination of various enzymes, mycelial age, digesting time and temperature, pH value, osmotic stabilizers, pretreatment, culture medium and culture method. Under the condition of mixed enzymes in osmotic stabilizer (0.6 M NaCl) combined with 2% lysozyme, 3% cellulase and 3% snailase, the highest protoplast yield, as high as 7.48×106 protoplasts/mL, was obtained when mycelial age was 60 h at pH 5.0–6.0 with digesting for 14–16 h at 28 °C. After purification of the obtained protoplasts, they were regenerated in PDA regenerative medium using bilayer plate culture method. To validate the usability of the protoplasts, a novel plasmid with green fluorescent protein (GFP) was used in transformation for easy visual observation. The results showed that the protoplasts prepared by the optimized method were active and applicable in further gene manipulation experiments. This work was presented at 13 ^th YABEC symposium held at Seoul, Korea, October 20–22, 2007.     

Onset of buoyancy-driven convection in melting from below

When a horizontal homogeneous solid is melted from below, convection can be induced in a thermally unstable melt layer. In this study the onset of buoyancy-driven convection during time-dependent melting is investigated by using similarly transformed disturbance equations. The critical Rayleigh numbers based on the melt-layer thickness are found numerically for various conditions. For small superheats, the present predictions approach the well known results of classical Rayleigh-Bénard problems, that is, critical Rayleigh numbers are located between 1,296 and 1,708, regardless of the Prandtl number. However, for high superheats the critical Rayleigh number increases with an increase in phase change rate but with decrease in Prandtl number.     

Laminar-turbulent transition in an electromagnetically levitated droplet

During experiments on the MSL-1 (first microgravity science laboratory) mission of the space shuttle (STS-83 and STS-94, April and July 1997), a droplet of palladium-silicon alloy was electromagnetically levitated for viscosity measurements. For the nondeforming droplet, the resultant magnetohydrodynamic (MHD) flow inside the drop can be inferred from motion of impurity particulates on the surface. In the experiments, subsequent to melting, Joule heating produces a continuous reduction of viscosity of the fluid resulting in an acceleration of the flow with time. These observations indicate formation of a pair of co-rotating toroidal flow structures inside the spheroidal drop that undergo flow instabilities. As the fluid temperature rises, the amplitude of the secondary flow increases, and beyond a point, the tracers exhibit noncoherent chaotic motion signifying emergence of turbulence inside the drop. Assuming that the observed laminar-turbulent transition is shear-layer type, the internal structure of the toroidal loops is used to develop a semiempirical correlation for the onset of turbulence. Our calculations indicate that the suggested correlation is in modest agreement with the experimental data, with the transition occurring at a Reynolds number of 600.     

SHS of shape memory CuZnAl alloys

Aiming at preparation of shape memory alloys (SMAs), we explored the SHS of Cu_{1 − x} Zn_{1 − y} Al_{1 − z} alloys (0.29 < x < 0.30, 0.74 < y < 0.75, and 0.83 < z < 0.96). The most pronounced shape memory effect was exhibited by the alloys of the following compositions (wt %): (1) Cu(70.6)Zn(25.4)Al(4.0), (2) Cu(70.1)Zn(25.9)Al(4.0), and (3) Cu(69.9)Zn(26.1)Al(4.0). The effect of process parameters on the synthesis of CuZnAl alloys was studied by XRD, optical microscopy, and scanning electron microscopy (SEM). The grain size of CuZnAl was found to depend on the relative amount of the primary CuZn and AlZn phases. Changes in the transformation temperature and heat of transformation are discussed in terms of ignition intensity and compaction. Mechanism of the process depends on the level of the temperature attained relative to the melting point of components. At the melting point of AlZn, the process is controlled by the solid-state diffusion of AlZn into a product layer. The ignition temperature for this system depends on the temperature of the austenite-martensite transformation in CuZnAl alloys. The composition and structure of the products was found to markedly depend on process parameters. The SHS technique has been successfully used to prepare a variety of SMAs.      

To treat or not to treat: comparison of different criteria used to determine whether weight loss is to be recommended

Background  

Excess body fat is a major risk factor for disease primarily due to its endocrine activity. In recent years several criteria have been introduced to evaluate this factor. Nevertheless, treatment need is currently assessed only on the basis of an individual's Body Mass Index (BMI), calculated as body weight (in kg) divided by height in m². The aim of our study was to determine whether application of the BMI, compared to adiposity-based criteria, results in underestimation of the number of subjects needing lifestyle intervention.     

Stochastic molecular descriptors for polymers. 4. Study of complex mixtures with topological indices of mass spectra spiral and star networks: The blood proteome case

The Quantitative Structure-Property Relationships (QSPRs) based on Graph or Network Theory are important for predicting the properties of polymeric systems. In the three previous papers of this series (Polymer 45 (2004) 3845-3853; Polymer 46 (2005) 2791-2798; and Polymer 46 (2005) 6461-6473) we focused on the uses of molecular graph parameters called topological indices (TIs) to link the structure of polymers with their biological properties. However, there has been little effort to extend these TIs to the study of complex mixtures of artificial polymers or biopolymers such as nucleic acids and proteins. In this sense, Blood Proteome (BP) is one of the most important and complex mixtures containing protein polymers. For instance, outcomes obtained by Mass Spectrometry (MS) analysis of BP are very useful for the early detection of diseases and drug-induced toxicities. Here, we use two Spiral and Star Network representations of the MS outcomes and defined a new type of TIs. The new TIs introduced here are the spectral moments (π_k) of the stochastic matrix associated to the Spiral graph and describe non-linear relationships between the different regions of the MS characteristic of BP. We used the MARCH-INSIDE approach to calculate the π_k(SN) of different BP samples and S2SNet to determine several Star graph TIs. In the second step, we develop the corresponding Quantitative Proteome-Property Relationship (QPPR) models using the Linear Discriminant Analysis (LDA). QPPRs are the analogues of QSPRs in the case of complex biopolymer mixtures. Specifically, the new QPPRs derived here may be used to detect drug-induced cardiac toxicities from BP samples. Different Machine Learning classification algorithms were used to fit the QPPRs based on π_k(SN), showing J48 decision tree classifier to have the best performance. These results suggest that the present approach captures important features of the complex biopolymers mixtures and opens new opportunities to the application of the idea supporting classic QSPRs in polymer sciences.     

Integrated carbon nanotube field emission differential amplifier: Modeling and measurement of the common-mode rejection ratio

A novel integrated vacuum field emission (VFE) differential amplifier (diff-amp) utilizing carbon nanotube (CNT) emitters has been developed. A dual-mask microfabrication process was employed to achieve a VFE diff-amp by integrating identical CNT VFE transistors with built-in split gates and integrated anodes. The identical pair of triode amplifiers was well-matched in their device characteristics. The measured ac small-signal characteristics of the diff-amp showed a common-mode-rejection ratio (CMRR) of ~ 320 (~ 50 dB). The proposed analytical model of the CMRR was verified to be in good agreement with the experimental data. The successful implementation of the CNT diff-amp demonstrates a new way to achieve temperature and radiation tolerant VFE integrated microelectronics.     

The relationship between bioelectrical impedance phase angle and subjective global assessment in advanced colorectal cancer

Background  

Bioelectrical Impedance (BIA) derived phase angle is increasingly being used as an objective indicator of nutritional status in advanced cancer. Subjective Global Assessment (SGA) is a subjective method of nutritional status. The objective of this study was to investigate the association between BIA derived phase angle and SGA in advanced colorectal cancer.