Over-expression of the X-linked inhibitor of apoptosis protein (XIAP) delays serum deprivation-induced apoptosis in CHO-K1 cells

Serum deprivation inhibits cell growth and initiates apoptosis cell death in mammalian cell cultures. Since apoptosis is a genetically controlled cell death pathway, over-expression of anti-apoptotic proteins may provide a way to delay apoptosis. This study investigated the ability of the X-linked inhibitor of apoptosis protein (XIAP) to inhibit apoptosis induced by serum deprivation. Study includes evaluation of the ability of XIAP to prolong culture period and its effect on cell proliferation in serum-deprived media. The full length human XIAP was introduced into CHO-K1 cell lines and the effects of XIAP over-expression on the inhibition of apoptosis induced by serum-deprived conditions were examined. In batch cultures, cells over-expressing XIAP showed decreased levels of apoptosis and a higher number of viable cell under serum-deprived conditions compared to the control cell lines. The viability of control cells dropped to 40% after 2 days of serum deprivation, the XIAP expressing cells still maintained at a viability higher than 90%. Further investigation revealed that the caspase-3 activity of the CHO-K1 cell line was inhibited as a result of XIAP expression.     

Identification of Proteins of Altered Abundance in Oil Palm Infected with Ganoderma boninense

Basal stem rot is a common disease that affects oil palm, causing loss of yield and finally killing the trees. The disease, caused by fungus Ganoderma boninense, devastates thousands of hectares of oil palm plantings in Southeast Asia every year. In the present study, root proteins of healthy oil palm seedlings, and those infected with G. boninense, were analyzed by 2-dimensional gel electrophoresis (2-DE). When the 2-DE profiles were analyzed for proteins, which exhibit consistent significant change of abundance upon infection with G. boninense, 21 passed our screening criteria. Subsequent analyses by mass spectrometry and database search identified caffeoyl-CoA O-methyltransferase, caffeic acid O-methyltransferase, enolase, fructokinase, cysteine synthase, malate dehydrogenase, and ATP synthase as among proteins of which abundances were markedly altered.     

Nanotubes-/nanowires-based,microfluidic-integrated transistors for detecting biomolecules

Nanotubes and nanowires have sparked considerable interest in biosensing applications due to their exceptional charge transport properties and size compatibility with biomolecules. Among the various biosensing methodologies incorporating these nanostructured materials in their sensing platforms, liquid-gated field-effect transistors (LGFETs)-based device configurations outperform the conventional electrochemical measurements by their ability in providing label free, direct electronic read-out, and real-time detection. Together with integration of a microfluidic channel into the device architecture, nanotube- or nanowires-based LGFET biosensor have demonstrated promising potential toward the realization of truly field-deployable self-contained lab-on-chip devices, which aim to complement the existing lab-based methodologies. This review addresses the recent advances in microfluidic-integrated carbon nanotubes and inorganic nanowires-based LGFET biosensors inclusive of nanomaterials growth, device fabrication, sensing mechanisms, and interaction of biomolecules with nanotubes and nanowires. Design considerations, factors affecting sensing performance and sensitivity, amplification and multiplexing strategies are also detailed to provide a comprehensive understanding of present biosensors and future sensor systems development.     

Ink and moisture sorption study in UV‐curable polyurethane acrylate

A study of the interaction of commercial black ink with a UV‐curable polyurethane acrylate (PUA) is presented. Diffusivity and solubility in PUA cured using different UV dosages, and subjected to different post‐UV curing conditions, were studied, as was the swelling produced by such sorption. Experiments were also conducted using water, to serve as a benchmark and compare with the effect of ink. The percentage ink absorption was found to decrease with higher degree of cure. In addition, through desorption measurements, ink induced swelling of PUA processed under different conditions was determined. The degree of swelling per unit solvent uptake was observed to increase with the degree of cure. PUA was determined to be more prone to moisture rather than solvent uptake. However, the coefficient of moisture expansion (CME) was found to be ～ 35% lower than the coefficient of ink expansion (CIE) for a fully cured PUA. © 2006 Wiley Periodicals, Inc. JAppl PolymSci 103: 1985–1991, 2007     

Sweetness intensity perception and pleasantness ratings of sucrose, aspartame solutions and cola among multi-ethnic Malaysian subjects

As the sugar intake of Malaysians is one of the highest in the Asia Pacific region, we wanted to investigate how this high prevalence of ‘sweet tooth’ is influenced by biological determinants like age, gender, ethnicity and Body Mass Index (BMI). This study therefore sought to use the generalized Labeled Magnitude Scale to evaluate the sweetness intensity perception and pleasantness ratings of not only three increasing suprathreshold concentrations of sucrose and a popular naturally-sweetened carbonated beverage - Coca-Cola®, but also their non-nutritive sweetener (NNS) counterparts - aspartame and Coca-Cola Light®. Taken together, the overall intensity of NNS solutions and beverage was perceived as significantly higher, but not for their pleasantness. The intensity perception and pleasantness of most sweet solutions were not significantly associated with gender and BMI. Overall, Malays had a lower perceived intensity of sweet stimuli compared to other ethnicities, but a conclusion of the influence of ethnicity on sweetness pleasantness could not be met. Lastly, sweetness intensity perception and pleasantness ratings for both colas decreased significantly with age.     

Pt nanodendrites anchored on bamboo-shaped carbon nanofiber arrays as highly efficient electrocatalyst for oxygen reduction reaction

In order to improve the Pt utilization and enhance their catalytic performance in fuel cells, a novel composite electrode composed of single-crystalline Pt nanodendrites and support constructed by bamboo-shaped carbon nanofiber arrays (CNFAs) on carbon paper, is reported. This electrode is designed by growing vertically CNFAs on carbon paper via plasma enhanced chemical vapor deposition, followed by the direct synthesis of Pt nanodendrites using a simple surfactant-free aqueous solution method. Electron microscopy studies reveal that the Pt nanodendrites are uniformly high dispersed and anchored on the surface of CNFAs. Electrochemical measurements demonstrate that the resultant electrode exhibits higher electrocatalytic activity and stability for oxygen reduction reaction than commercial Pt/C catalyst, suggesting its potential application in fuel cells.     

Chaotic Time Series Prediction Using a Neuro-Fuzzy System with Time-Delay Coordinates

This paper presents an investigation into the use of the delay coordinate embedding technique in the multi-input- multioutput-adaptive-network-based fuzzy inference system (MANFIS) for chaotic time series prediction. The inputs to the MANFIS are embedded-phase-space (EPS) vectors preprocessed from the time series under test, while the output time series is extracted from the output EPS vectors from the MANFIS. A moving root-mean-square error is used to monitor the error over the prediction horizon and to tune the membership functions in the MANFIS. With the inclusion of the EPS preprocessing step, the prediction performance of the MANFIS is improved significantly. The proposed method has been tested with one periodic function and two chaotic functions including Mackey-Glass chaotic time series and Duffing forced-oscillation system. The prediction performances with and without EPS preprocessing are statistically compared by using the t-test method. The results show that EPS preprocessing can help improve the prediction performance of a MANFIS significantly.     

Catalysis by Dihydrofolate Reductase from the Psychropiezophile Moritella profunda

The influence of temperature and pH on the stability and catalytic activity of dihydrofolate reductase (MpDHFR) from the cold‐adapted deep‐sea bacterium Moritella profunda was studied. The thermal melting temperature was found to be ～38 °C and was not affected by pH, while activity measurements demonstrated that its stability was maximal at pH 7 and was reduced dramatically below pH 6 or above pH 8. The steady‐state rate constant (k_cat) was maximal at neutral pH and higher temperatures, while the Michaelis constants (K_M) for both substrate and cofactor were optimal at lower temperatures and at elevated or reduced pH. For both temperature and pH, any change in k_cat was therefore offset by a similar change in K_M. Both the activation enthalpy and entropy of the MpDHFR‐catalysed reaction were lower than those of DHFR from E. coli leading overall to a very small difference in activation free energy and therefore similar steady‐state rate constants at the same temperature. The chemical step of the reaction is not rate limiting at pH 7, but becomes progressively more rate limiting as the pH increases. These results demonstrate adaptation of MpDHFR to its environment and show compromises between enthalpic and entropic contributions to the reaction, and between k_cat and K_M.     

Microsimulation modelling of driver behaviour towards alternative warning devices at railway level crossings

Level crossings are amongst the most complex of road safety issues, due to the addition of rail infrastructure, trains and train operations. The differences in the operational characteristics of different warning devices together with varying crossing, traffic or/and train characteristics, cause different driver behaviour at crossings. This paper compares driver behaviour towards two novel warning devices (rumble strips and in-vehicle audio warning) with two conventional warning devices (flashing light and stop sign) at railway level crossings using microsimulation modelling. Two safety performance indicators directly related to collision risks, violation and time-to-collision, were adopted. Results indicated the active systems were more effective at reducing likely collisions compared to passive devices. With the combined application of driving simulation and traffic microsimulation modelling, traffic safety performance indicators for a level crossing can be estimated. From these, relative safety comparisons for the different traffic devices are derived, or even for absolute safety evaluation with proper calibration from field investigations.     

Identification of vehicle suspension parameters by design optimization

The design of a vehicle suspension system through simulation requires accurate representation of the design parameters. These parameters are usually difficult to measure or sometimes unavailable. This article proposes an efficient approach to identify the unknown parameters through optimization based on experimental results, where the covariance matrix adaptation–evolutionary strategy (CMA-es) is utilized to improve the simulation and experimental results against the kinematic and compliance tests. This speeds up the design and development cycle by recovering all the unknown data with respect to a set of kinematic measurements through a single optimization process. A case study employing a McPherson strut suspension system is modelled in a multi-body dynamic system. Three kinematic and compliance tests are examined, namely, vertical parallel wheel travel, opposite wheel travel and single wheel travel. The problem is formulated as a multi-objective optimization problem with 40 objectives and 49 design parameters. A hierarchical clustering method based on global sensitivity analysis is used to reduce the number of objectives to 30 by grouping correlated objectives together. Then, a dynamic summation of rank value is used as pseudo-objective functions to reformulate the multi-objective optimization to a single-objective optimization problem. The optimized results show a significant improvement in the correlation between the simulated model and the experimental model. Once accurate representation of the vehicle suspension model is achieved, further analysis, such as ride and handling performances, can be implemented for further optimization.