Single-molecule biophysics: at the interface of biology, physics and chemistry

Single-molecule methods have matured into powerful and popular tools to probe the complex behaviour of biological molecules, due to their unique abilities to probe molecular structure, dynamics and function, unhindered by the averaging inherent in ensemble experiments. This review presents an overview of the burgeoning field of single-molecule biophysics, discussing key highlights and selected examples from its genesis to our projections for its future. Following brief introductions to a few popular single-molecule fluorescence and manipulation methods, we discuss novel insights gained from single-molecule studies in key biological areas ranging from biological folding to experiments performed in vivo.     

Security analysis of GTRBAC and its variants using model checking

Security analysis is a formal verification technique to ascertain certain desirable guarantees on the access control policy specification. Given a set of access control policies, a general safety requirement in such a system is to determine whether a desirable property is satisfied in all the reachable states. Such an analysis calls for the use of formal verification techniques. While formal analysis on traditional Role Based Access Control (RBAC) has been done to some extent, recent extensions to RBAC lack such an analysis. In this paper, we consider the temporal RBAC extensions and propose a formal technique using timed automata to perform security analysis by analyzing both safety and liveness properties. Using safety properties one ensures that something bad never happens while liveness properties show that some good state is also achieved. GTRBAC is a well accepted generalized temporal RBAC model which can handle a wide range of temporal constraints while specifying different access control policies. Analysis of such a model involves a process of mapping a GTRBAC based system into a state transition system. Different reduction rules are proposed to simplify the modeling process depending upon the constraints supported by the system. The effect of different constraints on the modeling process is also studied.     

Design and implementation of a realtime co-processor for denoising Fiber Optic Gyroscope signal

The amount of noise present in the Fiber Optic Gyroscope (FOG) signal limits its applications and has a negative impact on navigation system. Existing algorithms such as Discrete Wavelet Transform (DWT), Kalman Filter (KF) denoise the FOG signal under static environment, however denoising fails in dynamic environment. Therefore in this paper an Adaptive Moving Average Dual Mode Kalman Filter (AMADMKF) is developed for denoising the FOG signal under both the static and dynamic environments. Performance of the proposed algorithm is compared with DWT and KF techniques. Further, a hardware Intellectual Property (IP) of the algorithm is developed for System on Chip (SoC) implementation using Xilinx Virtex-5 Field Programmable Gate Array (Virtex-5FX70T-1136). The developed IP is interfaced as a Co-processor/ Auxiliary Processing Unit (APU) with the PowerPC (PPC440) embedded processor of the FPGA. It is proved that the proposed system is an efficient solution for denoising the FOG signal in real-time environment. Hardware acceleration of developed Co-processor is 65× with respect to its equivalent software implementation of AMADMKF algorithm in the PPC440 embedded processor.     

UV-reflecting wing scales in the silk moth Antheraea assamensis: its biophysical implications

Scanning electron microcopy of the wing scales from some specific locations in the silk moth, Antheraea assamensis, revealed the presence of 50-60-nm-thick microridges and 80-nm-thick air spaces between them. The principle of optics suggests that when the measured average thickness of microridges or lamellae is about 50-60 nm, that of the air-space between them is about 80-82 nm, then due to the known refractive index of air (1.0) and the infrared refractive index of lamellar cuticle (1.60), the lamellae (microridges) and the intervening lamellar air spaces will have similar optical thickness. A common optical thickness for the two types of layers causes the microridge structures to function in the fashion of a quarter wavelength interference filter and to reflect UV light. Behavioral studies under the natural conditions and short experimental exposure of the moths to artificial UV light suggests that coupling behavior of the moth is governed to a significant extent by these UV-reflecting wing scales. The importance of the study in overcoming a major problem of low autocoupling efficiency of moths in the Muga Silk Industry is discussed with the help of relevant literature.     

Development of fly ash-based automotive brake lining

Coal-fired power plants all over the world generate huge amounts of fly ash each year, 70 million tons of which are produced in the United States alone. Only 40% of all fly ashes generated in the USA find beneficial applications and rest have to be disposed off, which is burden for the generation industry. Fly ash particles possess certain characteristics that make them suitable for use in friction composites as a filler material. An attempt has been made through this research to incorporate more than 50 wt% of fly ash particles in automotive brake lining friction composites. This paper presents the research carried out on development of friction composites, using fly ash obtained from a specific power plant in Illinois. Ingredients such as phenolic resin, aramid pulp, glass fiber, potassium titanate, graphite, aluminum fiber and copper powder were used in the composite development phase, in addition to the fly ash. The developed brake lining composites have exhibited consistent coefficients of friction in the range of 0.35–0.4, and wear rates lower than 12 wt%.     

Compositing and Storage of Air and Wastewater Samples

The performance of a field study to determine whether any of the 14 New York City water pollution control plants are major sources of air pollution required sampling and the analysis of a large number of samples. To reduce the number of samples for analysis and address the associated storage concerns of the analytical laboratories, the experimental design called for compositing air and wastewater samples, and for investigating the stability of wastewater samples. This paper addresses the quality control issues associated with the compositing and stability components of the experimental design. The study tested the hypothesis that compositing techniques used for air and wastewater sampling lead to results that are not unlike those obtained by conventional grab sampling. The study also tested whether wastewater samples stored under proper laboratory conditions remain stable for a period longer than the conventionally accepted storage period of 2 weeks. Statistical analyses demonstrated that the hypotheses tested cannot be rejected and, consequently, compositing techniques employed in this study are equivalent to conventional grab sampling and the storage period of samples can be extended beyond the accepted 2 week period.     

Secure access privilege delegation using attribute-based encryption

International Journal of Information Security - Attribute-based encryption (ABE) is widely used for a secure and efficient data sharing. The predetermined access policy of ABE shares the data with...     

Biogenic Collagen-Nano ZnO Composite Membrane as Potential Wound Dressing Material: Structural Characterization,Antibacterial Studies and In Vivo Wound Healing Studies

Journal of Inorganic and Organometallic Polymers and Materials - The practical applicability of collagen, a natural polymer, as a wound dressing material is hindered due to its reduced stability...     

An intelligent instrument for tracking and adaptive filtering of oscillatory signals using Hebbian learning rules

In this paper Hebbian type of learning algorithms using total least squares method is applied for adaptive filtering techniques to remove the noise and undesired oscillatory signals at different systems. Here we have used the generalised Hebbian learning rules for initializing the internal representations of a feedforward neural network, which accelerates the convergence of supervised Hebbian learning rule. In case of constrained anti-Hebbian learning rule, the weight vectors of linear neuron unit is converged to an eigenvector which has the smallest eigenvalue. In the total least squares (TLS) method the noise rejection capability is superior to the least squares method. Here we have applied the initial sets of data for the internal representation of feedforward network which consists of bottom-up unsupervised learning process followed by top-down supervised learning process using total least squares (TLS) algorithm. For faster convergence we have included the momentum term for the updating of weights. An intelligent instrumentation scheme has been developed for on-line measurement of amplitude of oscillatory signals. The undesired oscillations of the signal is also removed by implementing neural network model (using Hebbian rules and total least square algorithm) on a digital signal processor.