Characterization of grafting density and binding efficiency of DNA and proteins on gold surfaces

The surface grafting density of biomolecules is an important factor for quantitative assays using a wide range of biological sensors. We use a fluorescent measurement technique to characterize the immobilization density of thiolated probe DNA on gold and hybridization efficiency of target DNA as a function of oligonucleotide length and salt concentration. The results indicate the dominance of osmotic and hydration forces in different regimes of salt concentration, which was used to validate previous simulations and to optimize the performance of surface-stress based microcantilever biosensors. The difference in hybridization density between complementary and mismatched target sequences was also measured to understand the response of these sensors in base-pair mismatch detection experiments. Finally, two different techniques for immobilizing proteins on gold were considered and the surface densities obtained in both cases were compared.     

Sets of periods of dynamical systems

In this article, we present a coherent, though not exhaustive, account of some well-known and some recent results of many mathematicians (including our own) on the following question: Given a “nice” class of dynamical systems, which subsets of ? arise as the sets of periods of members of that class? While stating and explaining some elegant answers, proofs have been outlined or indicated occasionally.     

Direct Form I Realization of Active Photonic Filters

Abstract

An integrated photonic architecture is introduced and used to realize an optical filter with direct form I realization. The architecture offers gain from semiconductor optical amplifiers, and this gain results in an active optical filter whose filter response depends on the individual gains. The presence of gain provides advantages in filter performance, and tunable and adaptive functionality. The optical filter is modeled as a discrete time system and the z-transform is used in its analysis and design. A low-pass filter design example is presented and the filter coefficients are derived in terms of gains and coupler splitting ratios. The region of stable operations is derived by applying the Schur-Cohn stability test.     

Self-Interacting Markov Chains: Some Asymptotics

Abstract

Guided by the self-interaction mechanisms introduced in Benaim et al. [2 Benaim , M. , Ledoux , M. , and Raimond , O. 2002 . Self-interacting diffusions . Probab. Theory Related Fields 122 : 1 – 41 . [Google Scholar]] and in [5 Del Moral , P. , and Miclo , L. 2006 . Self-interacting Markov chains . Stochastic Anal. Appl. 24 : 615 – 660 .[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]], we present a more general definition of self-interacting Markov chains (SIMCs) (than in Del Moral and Miclo [5 Del Moral , P. , and Miclo , L. 2006 . Self-interacting Markov chains . Stochastic Anal. Appl. 24 : 615 – 660 .[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]] and Benaim et al. [2 Benaim , M. , Ledoux , M. , and Raimond , O. 2002 . Self-interacting diffusions . Probab. Theory Related Fields 122 : 1 – 41 . [Google Scholar]]). We then establish, for particular self-interaction mechanisms, a stability theorem with error estimation, two central limit theorems, two functional central limit theorems, and the large deviation principle.     

Synthesis,photophysical, and electrochemical properties of triazolyl dendrimers with thiazolylchalcone surface unit

Synthesis of novel triazolyl dendrimers with thiazolylchalcone surface group and triazole as bridging unit has been achieved in good yields by click chemistry through convergent approach. All the triazolyl dendrimers showed an absorption band between 293 and 336?nm and an emission band between 430 and 435?nm. The intensity of absorption and emission bands increases on increasing the number of dendritic wedges and triazole units. Triazolyl dendrimers exhibited quasi-reversible behavior in cyclic voltammetry. A shift in the reversible potential was observed in cyclic voltammetry on increasing the dendritic wedges in the triazolyl dendrimers.     

Hydroxylamine on Clay: a Direct Synthesis of Nitriles from Aromatic Aldehydes Using Microwaves Under Solvent-Free Conditions

In a solvent-free system, hydroxylamine hydrochloride impregnated montmorillonite K 10 clay expeditiously converts arylaldehydes to the corresponding nitriles under microwave irradiation conditions. This rapid one-pot method produces pure products in high yields (89–95%) within 1 to 1.5 min.