Label-free protein recognition two-dimensional array using nanomechanical sensors

We demonstrate two-dimensional multiplexed real-time, label-free antibody-antigen binding assays by optically detecting nanoscale motions of two-dimensional arrays of microcantilever beams. Prostate specific antigen (PSA) was assayed using antibodies covalently bound to one surface of the cantilevers by two different surface chemistries, while the nonreaction surfaces were passivated by poly(ethylene glycol)-silane. PSA as low as 1 ng/mL was detected while 2 mg/microl of bovine serum albumin induced only negligible deflection on the cantilevers.     

Towards crossbar nanoarray structure via microcontact printing

The method for patterning arrays of multiwalled carbon nanotubes (MWCNT's) in symmetric patterns to form junctions has been demonstrated. This has been achieved by incorporating the technique of microcontact printing using poly-dimethylsiloxane (PDMS) molds. Relief structures in the order of a few micrometers were fabricated that enabled the transfer of continuous horizontal arrays of MWCNT's in aqueous suspension in a controlled manner. The MWCNT's were patterned onto silicon microelectrode substrates with metallic gold electrodes. These were fabricated using standard photolithography techniques. The silicon substrates served as a base platform with suitable measurement microelectrodes for electrically characterizing the crossbar junction arrays. Using a dual alignment and stamping process, PDMS molds were inked alternatively with p-type and n-type suspensions of MWCNT's and transferred in a grid-like manner onto the base platform. Parallel alignment of the MWCNT's was achieved due to the geometry of the mold relief structures. This step-by-step assembly resulted in the formation of crossbar MWCNT array structures. Each of these crosspoints in the individual junction can function as an addressable crossbar nanodevice. The functionality of this circuit was demonstrated through the current-voltage (I-V) characteristics. Using these high-density crossarray circuit patterns, addressable nanostructures that form the building blocks of highly integrated device arrays can be built.     

Bacterial synthesis of copper/copper oxide nanoparticles

A bacterial mediated synthesis of copper/copper oxide nanoparticle composite is reported. A Gram-negative bacterium belonging to the genus Serratia was isolated from the midgut of Stibara sp., an insect of the Cerambycidae family of beetles found in the Northwestern Ghats of India. This is a unique bacterium that is quite specific for the synthesis of copper oxide nanoparticles as several other strains isolated from the same insect and common Indian mosquitoes did not result in nanoparticle formation. By following the reaction systematically, we could delineate that the nanoparticle formation occurs intracellularly. However, the process results in the killing of bacterial cells. Subsequently the nanoparticles leak out as the cell wall disintegrates. The nanoparticles formed are thoroughly characterized by UV-Vis, TEM, XRD, XPS and FTIR studies.     

TEM studies on recovery and recrystallisation in Equal Channel Angular Extrusion processed Al-3%Mg alloy

Equal Channel Angular Extrusion (ECAE) is a promising severe plastic deformation (SPD) process which can produce polycrystalline materials with ultra-fine grains (UFG) of sub micrometer range or nanometer range. Large plastic shear deformation induced by the high applied pressure in ECAE material processing is the prime reason behind the grain refinement. The focus of the present work is to study the evolution of dislocation microstructure during dynamic recovery (due to intense strain deformation) and static recovery (due to static annealing after deformation) in commercial Al-3%Mg alloy processed by ECAE. It is observed that local concentrations of shear strain can take place and high angle boundary (HAGB) segments are formed initially at random locations. When thermal energy is provided, during static annealing, the boundary segments get further defined and extended. This leads to the formation of very fine size grains with high mis-orientations which subsequently develop into an ultra-fine grain distribution in the material. Also, it appears dynamic recrystallisation (DRX) occurring during the deformation itself is a general phenomenon leading to refinement of grains. Transmission Electron Microscopy (TEM) is the characterizing tool used in the present study. The influence of precipitates/second phase particles on the deformation characteristics and on the increased degree of grain fragmentation is also detailed.     

Low digestion property of amylosucrase-modified waxy adlay starch

Structural and digestion properties of amylosucrase-modified waxy adlay starch were investigated. The unique reaction of amylosucrase caused a decrease and an increase in the proportion of short chains and long chains, respectively, via attachment of glucosyl units to the non-reducing ends of branch chains. The in vitro digestion profile of amylosucrase-modified starch revealed that elongated branch chains were the main reason for high contents of slowly digestible and resistant starches due to formation of a more perfect crystalline structure via easy association between elongated branch chains. The glucose response in mice after consumption of amylosucrase-modified starch was similar to the response for commercial resistant starch with a gradual increase followed by a gradual decrease in blood glucose concentrations over a prolonged time. Both in vitro and in vivo tests were used to verify increased resistance to digestive enzymes caused by amylosucrase modification.     

Incoherent transport in NEMO5: realistic and efficient scattering on phonons

In this work, the coherent and incoherent transport simulation capabilities of the multipurpose nanodevice simulation tool NEMO5 are presented and applied on transport in tunneling field-effect transistors. The comparison with experimental resistivity data confirms the validity of NEMO5’s phonon-scattering models. Common pitfalls of numerical implementations and the applicability of common approximations of scattering self-energies are discussed. The impact of phonon-assisted tunneling on the performance of TFETs is exemplified with a concrete Si nanowire device. The communication-efficient implementation of self-energies in NEMO5 is demonstrated with a scaling comparison of self-energies solved with blocking and nonblocking MPI-communication.     

Porosity Development of Activated Carbons Prepared from Wild Almond Shells and Coir Pith Using Phosphoric Acid

Activated carbons (ACs) are prepared from wild almond shells (AS) and coir pith (CP) using phosphoric acid as an activating agent. Various process parameters like acid concentration, impregnation ratio, activation temperature, and time are optimized for better iodine adsorption capacity and yield. The impregnation ratio and the activation temperature are found to be the key parameters governing the porosity, surface area, and the yield of AC. The Brunauer-Emmett-Teller (BET) analysis of ACs shows that the surface areas are 1133.25 and 1210.58 m²/g with the yields of 32.8 and 40.7%, respectively, produced from wild AS and CP. The maximum adsorption capacities for methylene blue are as high as 788.88 and 708.33 mg/g. The equilibrium data is best described by the Langmuir and the Temkin isotherm, while the adsorption follows second-order kinetics, indicating that the intraparticle diffusion is one of the rate-controlling steps.     

MECOR: Minimal Energy Consumption with Optimized Routing in MANET

Energy and routing efficiency is a long-research topic from past decades in the area of MANET. The prior research contribution focusing on addressing both the issues are associated with issues like (1) few benchmarked studies, (2) adoption of conventional routing protocols based on shortest path to mitigate both issues, and (3) inefficient design principles of routing. Hence, this paper proposes a novel routing protocol in mobile ad hoc network (MANET) termed as MECOR i.e. minimal energy consumption with optimized routing. MECOR presents a simple communication strategy based on mathematical and signaling properties of mobile nodes in MANET to jointly address the energy and routing issues in MANET. The outcome of the MECOR was compared with conventional routing algorithm as well as recent studies of energy efficient routing policy to find that MECOR can minimize 58.82 % of energy in most challenging mobility scenarios of MANET.