Combined Effects of Confinement and Macromolecular Crowding on Protein Stability

Confinement and crowding have been shown to affect protein fates, including folding, functional stability, and their interactions with self and other proteins. Using both theoretical and experimental studies, researchers have established the independent effects of confinement or crowding, but only a few studies have explored their effects in combination; therefore, their combined impact on protein fates is still relatively unknown. Here, we investigated the combined effects of confinement and crowding on protein stability using the pores of agarose hydrogels as a confining agent and the biopolymer, dextran, as a crowding agent. The addition of dextran further stabilized the enzymes encapsulated in agarose; moreover, the observed increases in enhancements (due to the addition of dextran) exceeded the sum of the individual enhancements due to confinement and crowding. These results suggest that even though confinement and crowding may behave differently in how they influence protein fates, these conditions may be combined to provide synergistic benefits for protein stabilization. In summary, our study demonstrated the successful use of polymer-based platforms to advance our understanding of how in vivo like environments impact protein function and structure.     

Recent Study on Schottky Tunnel Field Effect Transistor for Biosensing Applications

Silicon - In this review, we discussed highly sensitive biosensor devices which is having a more attractive, wide scope and development in the sensing field. Biosensor devices can detect the...     

Source-Drain Junction Engineering Schottky Barrier MOSFETs and their Mixed Mode Application

Silicon - In this paper, a new structure for a silicon on insulator Schottky barrier MOSFET (SOI SB-MOSFET) has been proposed. The simulated device is calibrated with experimental result. Here...     

Fourier transform infrared-probed O(3P) microreactor: demonstration with ethylene reactions in argon matrix

To demonstrate the development of an oxygen atom microreactor in the form of liquid-helium-cooled solid argon matrix deposited on an infrared (IR) window, the oxidation of ethylene by mobile O atoms has been investigated. O atom diffusion through the argon matrix is confirmed and used to examine ethylene-oxygen atom reactions. In a bench-scale matrix isolation system probed with a Fourier transform infrared (FT-IR) spectrometer, matrices of solid Ar at 8-10 K doped with NO2 and ethylene have been prepared on a ZnSe window within an evacuated cryostat. The matrices have been photolyzed using 350-450 nm photons, and the reaction products resulting from the reaction of O(3P), one of the photolysis products of NO2, with ethylene have been identified using FT-IR and a Gaussian 98W simulation program. These products include oxirane, acetaldehyde, ethyl nitrite radical, and ketene. The temperature effect in the range of 10-30 K on the products formed has also been investigated. The reaction mechanisms are discussed and the viability of the solid Ar matrix being a low temperature microreactor to examine reaction mechanisms of mobile oxygen atoms is elaborated.     

An adaptive hybrid time‐stepping scheme for highly non‐linear strongly coupled problems

This paper deals with the design and implementation of an adaptive hybrid scheme for the solution of highly non‐linear, strongly coupled problems. The term ‘hybrid’ refers to a composite time stepping scheme where a controller decides whether a monolithic scheme or a fractional step (splitting) scheme is appropriate for a given time step. The criteria are based on accuracy and efficiency. The key contribution of this paper is the development of a framework for incorporating error criteria for stepsize selection and a mechanism for choosing from splitting or monolithic possibilities. The resulting framework is applied to silylation, a highly non‐linear, strongly coupled problem of solvent diffusion and reaction in deforming polymers. Numerical examples show the efficacy of our new hybrid scheme on both two‐ and three‐dimensional silylation simulations in the context of microlithography. Copyright © 2005 John Wiley & Sons, Ltd.     

Storage studies of mango packed using biodegradable chitosan film

The effect on the quality of mango fruits (Mangifera indica) during modified atmosphere packaging was investigated. The fruits were kept in carton boxes whose top surface was covered with either chitosan film or with low-density polyethylene (positive control) or kept as such (control) and stored at room temperature (27ǃ °C at 65% RH). The CO₂ and O₂ levels measured on day 3 were 23-26% and 3-6%, and at the end of the storage period they were 19-21% and 5-6%, respectively. Various quality parameters such as colour, chlorophyll, acidity, vitamin C, carotenoid and sugar contents were studied. The fruits stored as such had a shelf-life of 9ǃ days, whereas those stored in low-density polyethylene showed off-flavour due to fermentation and fungal growth on the stalk and around the fruits, and were partially spoiled. On the other hand, fruits stored in chitosan-covered boxes showed an extension of shelf-life of up to 18 days and without any microbial growth and off-flavour. Being biodegradable and ecofriendly, chitosan films are useful as an alternative to synthetic packaging films in the storage of freshly harvested mangoes.     

Cure characterization of the ring‐opening metathesis polymerization of linseed oil‐based thermosetting resins

BACKGROUND: Bio‐based polymers from vegetable oils are excellent alternatives to petroleum‐based resins for both environmental and economic reasons. A detailed understanding of the cure behavior of bio‐based polymers is essential to optimize cure schedules and the final properties of the polymers. In this work, the cure of newly developed linseed oil‐based thermosetting resins, synthesized using Grubbs' first‐generation catalyst and a bis‐norbornadiene cross‐linking agent by ring‐opening metathesis polymerization, is characterized using differential scanning calorimetry (DSC) and parallel plate oscillatory rheometry. RESULTS: Experimental results reveal that the rate of cure increases and the gel time decreases with increasing cross‐linker loading; however, the activation energy of the cure does not vary systematically with cross‐linker loading. Phenomenological reaction models are used to describe the dynamic DSC measurements and to determine the kinetic parameters which facilitate cure predictions under isothermal conditions. CONCLUSION: This work demonstrates that the cure kinetics of a linseed oil‐based thermosetting resin can be controlled by varying the cross‐linker loading. Furthermore, the kinetic parameters and cure rates at any cross‐linker loading for this system can be described by a simple autocatalytic reaction model which facilitates development of cure schedules. Copyright © 2009 Society of Chemical Industry     

Gradually Varied Flow Computation in Cyclic Looped Channel Networks

A novel and computationally efficient algorithm is presented to compute the water surface profiles in steady, gradually varied flows of open channel networks. This algorithm allows calculation of flow depths and discharges at all sections of a cyclic looped open channel network. The algorithm is based on the principles of (1) classifying the computations in an individual channel as an initial value problem or a boundary value problem; (2) determining the path for linking the solutions from individual channels; and (3) an iterative Newton–Raphson technique for obtaining the network solution, starting from initial assumptions for discharges in as few channels as possible. The proposed algorithm is computationally more efficient than the presently available direct method by orders of magnitude because it does not involve costly inversions of large matrices in its formulation. The application of this algorithm is illustrated through an example network.