Conformational changes due to externally applied physiochemical parameters, including pH, temperature, solvent composition, and mechanical forces, have been extensively reported for numerous proteins. However, investigations on the effect of fluid shear flow on protein conformation remain inconclusive despite its importance not only in the research of protein dynamics but also for biotechnology applications where processes such as pumping, filtration, and mixing may expose protein solutions to changes in protein structure. By combining particle image velocimetry and Raman spectroscopy, we have successfully monitored reversible, shear-induced structural changes of lysozyme in well-characterized flows. Shearing of lysozyme in water altered the protein's backbone structure, whereas similar shear rates in glycerol solution affected the solvent exposure of side-chain residues located toward the exterior of the lysozyme alpha-domain. The results demonstrate the importance of measuring conformational changes in situ and of quantifying fluid stresses by the three-dimensional shear tensor to establish reversible unfolding or misfolding transitions occurring due to flow exposure.

By directly monitoring stirred protein solutions with Raman spectroscopy, the reversible unfolding of proteins caused by fluid shear is examined for several natural proteins with varying structural properties and molecular weight. While complete denaturation is not observed, a wide range of spectral variances occur for the different proteins, indicating subtle conformational changes that appear to be protein-specific. A number of significant overall trends are apparent from the study. For globular proteins, the overall extent of spectral variance increases with protein size and the proportion of beta-structure. For two less structured proteins, fetuin and alpha-casein, the observed changes are of relatively low magnitude, despite the greater molecular structural mobility of these proteins. This implies that other protein-specific factors, such as posttranslational modifications, may also be significant. Individual band changes occurring in the spectral profiles of each individual protein are also discussed in detail.

The transition pathway leading to chaotic flow in a Taylor-Couette vessel of aspect ratio ␥ = 11.2 and radius ratio = 0.81 with only the inner cylinder rotating has been studied using time-resolved particle image velocimetry. A hitherto unreported sequence of transitions, whereby the flow changes from wavy vortex flow to a quasiperiodic state of high modulation frequency, is identified using spatially resolved spectral analysis. The nature of the modulated wavy vortex flow is detailed using proper orthogonal decomposition, through which it is revealed that the modulation is similar to a fast moving azimuthal wave ͑FMAW͒. In contrast with previous observations of the FMAW at a much higher aspect ratio, the mode appears directly after wavy vortex flow and as a precursor to the CVF regime. The FMAW is also associated with codirectional vorticity fluctuations on each Taylor vortex core that diminish in strength close to the endwalls.

Purpose Nowadays with the rapid growth of futures market, trust issues are increasing, especially, for individual traders because of the existing risks. However, to date there is no study that focuses on trust issues within online futures market and risks that threaten individual traders. This paper aims to understand trust issues in online futures market. Design/methodology/approach This study adopts an in-depth qualitative approach of online futures market in Malaysia through 30 interviews include senior managers, managers and individual traders who involve in futures online trading from three brokerage firms. Using agency theory, a new scale model, this study provides understanding on trust issues for traders in online futures market. Findings The paper provides empirical insights about trust issues that will occur as a result of information, risk and goal asymmetries between traders and brokers in online futures market. It suggests licensed and registered broker, platform familiarity, platform accessibility and usability, flexible contract size and leverage, providing segregated account and appropriate devices as key elements to overcome the mentioned asymmetries. Originality/value This is the first paper to investigate existing risk in online futures market and provide valuable implications for both traders and brokers to reduce the risk and increase the traders’ trust.