NANOSCALE
Year:2015 | Volume:2 | Issue:3|Papers Count:6

In the present work, Cu-doped ZnSe Nanocrystals (NCs) synthesized for 5, 10 and 15 min illumination times and different concentrations of impurity by photochemical method. XRD and TEM analysis demonstrated zinc blende phase NCs with an average size of around 3nm. UV-Vis analysis showed the band gap of ZnSe NCs decreased from 3.8 to 3.45eV for 5 to 15 min synthesis time. PL spectra of ZnSe NCs showed a broad emission with two peaks located at 380 and 490 nm related to exitonic and trap states emission, respectively. For ZnSe: Cu NCs, exitonic emission decreased and PL intensity of trap states emission increased by increasing the synthesis time so that after 10 min, exitonic emission quenched completely and trap states emission reached to its maximum value.

In this paper, electron transport in a metal/molecule/metal molecular system Includes biphenyl-dithiol molecule and three-dimensional gold electrodes for three different types of contact geometry, are investigated. The Hamiltonian of the molecule is calculated based on the Hückel method and the current is computed by the non-equilibrium Green’s function method in the framework of Landauer–Büttiker formalism. Transmission coefficient and current voltage characteristics are calculated for three different geometric structures. The results show that electron transport is strongly affected by quantum interference of electron waves and the geometry of the molecule-electrode interface. The current amplitude for symmetric coupling is larger than two other asymmetric couplings because of the quantum interference effects of the electron waves traveling through the different paths.

Acute Myocardial Infarction (AMI) is one of the leading causes of death throughout the world. Usual methods for detecting AMI are expensive, time-consuming and using blood samples as biological samples. Therefore, creating an ultra-fast, sensitive and non-invasive diagnostic test is necessary. Herein, a novel ultra-sensitive, fluorescent, plasmon-exciton coupling hybrid of a Gold Nano Rod-Quantum Dot (RQ) -based aptamer nanobiosensor is presented for the detection of human cardiac troponin I (cTnI), the golden biomarker of AMI, and a preclinical test is performed with saliva. The binding of the cTnI protein to aptamer leads to a fluorescence enhancement of the plexcitonic hybrid system. The limit of detection of this nanobiosensor is 0.5 fM. It seems this novel nanobiosensor of the RQ plexcitonic hybrid system can open up new opportunities for the design and fabrication of nanobiosensor progress in Nano biotechnology.

In this work, Supported copper (II) on functionalized Fe3O4 magnetic nanoparticles was used as high efficient and magnetically recoverable catalyst for the oxidation of sulfides to sulfoxides and oxidative coupling of thiols into corresponding disulfides using hydrogen peroxide (H2O2) as oxidant. An aliphatic and aromatic series of sulfides and thiols including various functional groups was successfully converted into corresponding products. All of products were obtained in good to excellent yields. The magnetic nanocatalyst was characterized by FTIR spectroscopy, TEM, XRD, SEM, and TGA techniques. Recovery of the catalyst is easily performed via magnetic decantation and reused for several consecutive runs without significant loss of its catalytic efficiency and activity.

We have investigated the behavior of dynamical thermal conductivity of doped biased bilayer graphene for AB-stacking as a function of frequency in the context of tight-binding model Hamiltonian. In this work, it has considered frequency dependence of temperature gradient. Green’s function approach has been implemented to find the behavior of thermal conductivity of bilayer graphene within Kubo linear response theory. Different behaviors have been seen for thermal conductivity due to different frequency. Also thermal conductivity versus bias and temperature has investigated. Dynamical thermal conductivity decreases with chemical potential, bias voltage and temperature, while it has a relative fluctuation with frequency at high bias voltage and high temperature.

In this research, coaxial electro spinning method was used for preparing the core-shell fibers of polycaprolactone (PCL) and polyvinyl alcohol (PVA), and silver nanoparticles were added through the reduction of silver nitrate in core solution before processing. The presence of silver nanoparticles was proved by observing the absorption peak in UV-visible spectroscopy test in the range of 420-430 nm. Antibacterial properties were investigated according to ATCC100 standard by usage of E.coli and S.aureus bacteria on single layer fibers mat of PCL, PVA, PCL containing silver and PVA containing silver, as well as core-shell fibers mat of PVA-Ag/PCL and PCL-Ag/PVA. The results showed that core-shell fibers have strong antibacterial properties like single layer fibers containing silver. Also, adding silver nanoparticles caused a slight enhancement in contact angle or hydrophobicity of the fibers. The water vapor transmission rate test exhibited that WVTR value decreased with the addition of silver and fabricating core-shell fibers while in comparison with commercial wound dressing, this value is more close to human WVTR value.