Bench-to-bedside review: Vaccine protection strategies during pandemic flu outbreaks

Vaccination is the most effective means for the prevention of influenza, including pandemic strains. An ideal pandemic influenza vaccine should provide effective protection with the fewest number of doses in the shortest amount of time, and among the greatest proportion of the population. The current manufacturing processes required for embryonated chicken-egg-based influenza vaccines are limited in their ability to respond to pandemic situations - these limitations include problems with surge capacity, the need for egg-adapted strains, the possibility of contamination, and the presence of trace egg protein. Several vaccine strategies to circumvent the deficiencies intrinsic to an egg-based influenza vaccine are in various phases of development. These include the use of cell-culture-based growth systems, concomitant use of adjuvants, whole virus vaccines, recombinant protein vaccines, plasmid DNA vaccines, virus-like particle vaccines, and universal flu vaccines

The elemental mechanism of transcriptional pausing.

Transcriptional pausing underlies regulation of cellular RNA biogenesis. A consensus pause sequence that acts on RNA polymerases (RNAPs) from bacteria to mammals halts RNAP in an elemental paused state from which longer-lived pauses can arise. Although the structural foundations of pauses prolonged by backtracking or nascent RNA hairpins are recognized, the fundamental mechanism of the elemental pause is less well-defined. Here we report a mechanistic dissection that establishes the elemental pause signal (i) is multipartite; (ii) causes a modest conformational shift that puts γ-proteobacterial RNAP in an off-pathway state in which template base loading but not RNA translocation is inhibited; and (iii) allows RNAP to enter pretranslocated and one-base-pair backtracked states easily even though the half-translocated state observed in paused cryo-EM structures rate-limits pause escape. Our findings provide a mechanistic basis for the elemental pause and a framework to understand how pausing is modulated by sequence, cellular conditions, and regulators

The Effect of Periodic Silane Burst on the Properties of GaN on Si (111) Substrates

The periodic silane burst technique was employed during metalorganic chemical vapor deposition of epitaxial GaN on AlN buffer layers grown on Si (111). Periodic silicon delta doping during growth of both the AlN and GaN layers led to growth of GaN films with decreased tensile stresses and decreased threading dislocation densities, as well as films with improved quality as indicated by x-ray diffraction, micro-Raman spectroscopy, atomic force microscopy, and transmission electron microscopy. The possible mechanism of the reduction of tensile stress and the dislocation density is discussed in the paper.Singapore-MIT Alliance (SMA

Large eddy simulation of free-surface flows

This paper introduces and discusses numerical methods for free-surface flow simulations and applies a large eddy simulation (LES) based free-surface-resolved CFD method to a couple of flows of hydraulic engineering interest. The advantages, disadvantages and limitations of the various methods are discussed. The review prioritises interface capturing methods over interface tracking methods, as these have shown themselves to be more generally applicable to viscous flows of practical engineering interest, particularly when complex and rapidly changing surface topologies are encountered. Then, a LES solver that employs the level set method to capture free-surface deformation in 3-D flows is presented, as are results from two example calculations that concern complex low submergence turbulent flows over idealised roughness elements and bluff bodies. The results show that the method is capable of predicting very complex flows that are characterised by strong interactions between the bulk flow and the free-surface, and permits the identification of turbulent events and structures that would be very difficult to measure experimentally

Prioritising Research Agenda For E-Commerce In Malaysia

The recent advent of World Wide Web has changed the traditional marketing paradigm in a dramatic way. Under a computer-mediated marketing framework the operations are no longer controlled by boundaries and time constraints. The new paradigm provides firms the whole wired world as potential market to capture. This is the underlying rationale for the Malaysian e-commerce policy or marketing in a "computer-mediated-environment" in Malaysia. Although, the concept of e-commerce is relatively new in this country, but, it was widely accepted marketing medium among the developed nations. Whether Malaysia is able to reap the benefits of e-commerce largely depends on various factors ranging from the infrastructures, the skill base, the critical mass of internet users, legal policy and so on. Understanding the nature of the relationship and the significance of these factors require a good amount of research in the industry perspectives. This paper attempts to provide some guidelines about the research priorities in marketing of Malaysian produce and products under a computer-mediated-environment; taking into account the local and peculiarities of the firms and consumers' behaviour. In this respect the current paper draws literatures about e-commerce experiences of other countries for the purpose of benchmarking. The preliminary conclusion drawn from these literatures suggest that e-marketing outcomes are major reduction in transaction costs and an increase in productivity; which in turn radically change the traditional market structure, behaviour and performance framework. While it is envisaged that the private sector will take the lead role in the development of e-marketing in Malaysia, the government has a bigger role in ensuring its sustainability. The major research issues in economics and marketing are: the competitiveness of the related industries to allow higher investment in bandwidth and high-technology, integration of physical and online marketing, the economics of network management, characteristics and perception of the community on e-commerce, market and commercial governance, the current and future skill of the community, monitoring the changes in marketing functions and intermediary roles and providing macro indicators to measure the market

Intermittent generalized synchronization in unidirectionally coupled chaotic oscillators

A new behavior type of unidirectionally coupled chaotic oscillators near the generalized synchronization transition has been detected. It has been shown that the generalized synchronization appearance is preceded by the intermitted behavior: close to threshold parameter value the coupled chaotic systems demonstrate the generalized synchronization most of the time, but there are time intervals during which the synchronized oscillations are interrupted by non-synchronous bursts. This type of the system behavior has been called intermitted generalized synchronization (IGS) by analogy with intermitted lag synchronization (ILS) [Phys. Rev. E \textbf{62}, 7497 (2000)].Comment: 8 pages, 5 figures, using epl.cls; published in Europhysics Letters. 70, 2 (2005) 169-17