Single-walled carbon nanotube-based polymer monoliths for the enantioselective nano-liquid chromatographic separation of racemic pharmaceuticals

Many protocols have been used for extraction of DNA from Thraustochytrids. These generally involve the use of CTAB, phenol/chloroform and ethanol. They also feature mechanical grinding, sonication, N2 freezing or bead beating. However, the resulting chemical and physical damage to extracted DNA reduces its quality. The methods are also unsuitable for large numbers of samples. Commercially-available DNA extraction kits give better quality and yields but are expensive. Therefore, an optimized DNA extraction protocol was developed which is suitable for Thraustochytrids to both minimise expensive and time-consuming steps prior to DNA extraction and also to improve the yield. The most effective method is a combination of single bead in TissueLyser (Qiagen) and Proteinase K. Results were conclusive: both the quality and the yield of extracted DNA were higher than with any other method giving an average yield of 8.5 µg/100 mg biomass.

Pre-lithiation of onion-like carbon/MoS2 nano-urchin anodes for high-performance rechargeable lithium ion batteries

Hybrid urchin-like nanostructures composed of a spherical onion-like carbon (OLC) core and MoS2 nanoleaves were synthesized by a simple solvothermal method followed by thermal annealing treatment. Compared to commercial MoS2 powder, MoS2/OLC nanocomposites exhibit enhanced electrochemical performance as anode materials of lithium-ion batteries (LIBs) with a specific capacity of 853 mA h g−1 at a current density of 50 mA g−1 after 60 cycles, and a moderate initial coulombic efficiency of 71.1%. Furthermore, a simple pre-lithiation method based on direct contact of lithium foil with MoS2/OLC nano-urchins was used to achieve a very high coulombic efficiency of 97.6% in the first discharge/charge cycle, which is at least 26% higher compared to that of pristine MoS2/OLC nano-urchins. This pre-lithiation method can be generalized to develop other carbon-metal sulfide nanohybrids for LIB anode materials. These results may open up a new avenue for the development of the next-generation high-performance LIBs.

Optimizing the quantum dot: Plasmon interaction in a nano gap waveguide

Spontaneous emission (SE) of a Quantum emitter depends mainly on the transmission strength between the upper and lower energy levels as well as the Local Density of States (LDOS)[1]. When a QD is placed in near a plasmon waveguide, LDOS of the QD is increased due to addition of the non-radiative decay and a plasmonic decay channel to free space emission[2-4]. The slow velocity and dramatic concentration of the electric field of the plasmon can capture majority of the SE into guided plasmon mode (Гpl ). This paper focused on studying the effect of waveguide height on the efficiency of coupling QD decay into plasmon mode using a numerical model based on finite elemental method (FEM). Symmetric gap waveguide considered in this paper support single mode and QD as a dipole emitter. 2D simulation models are done to find normalized Гpl and 3D models are used to find probability of SE decaying into plasmon mode ( β) including all three decay channels. It is found out that changing gap height can increase QD-plasmon coupling, by up to a factor of 5 and optimally placed QD up to a factor of 8. To make the paper more realistic we briefly studied the effect of sharpness of the waveguide edge on SE emission into guided plasmon mode. Preliminary nano gap waveguide fabrication and testing are already underway. Authors expect to compare the theoretical results with experimental outcomes in the future

Multipurpose nanoporous alumina-carbon nanowall bi-dimensional nano-hybrid platform via catalyzed and catalyst-free plasma CVD

Simple, rapid, plasma-assisted synthesis of large-area arrays of vertically-aligned carbon nanowalls on highly-porous, transparent bare and gold-coated alumina membranes with the two pore sizes is reported. It is demonstrated that the complex patterns of vertically aligned nanowalls can nucleate and form different morphologies in the low-temperature plasmas. The process is stable, and the twofold change in the gas flow (10 and 20 sccm) does not noticeably influence the morphology of the nanowall pattern. Application of a thin (5 nm) gold layer to nanoporous membrane prior to the nanowall growth allows controlling the network morphology.

Patterned growth of nanoscale in clusters on the Si(111)-7×7 and Si(111)-Ge(5×5) reconstructions

Results of a study designed to investigate the possibility of using the Si(111)- Ge(5×5) surface reconstruction as a template for In cluster growth are described. As with Si(111)-7×7, the In adatoms preferentially adsorb in the faulted half-unit cell, but on Si(111)- Ge(5×5) a richer variety of cluster geometries are found. In addition to the clusters that occupy the faulted half-unit cell, clusters that span two and four half-unit cells are found. The latter have a triangular shape spanning one unfaulted and three, nearest neighbor, faulted half-unit cells, Triangular clusters in the opposite orientation were not found. Many of the faulted halfunit cells have a streaked appearance consistent with adatom mobility.

Nano-indentation studies on polymer matrix composites reinforced by few-layer graphene

The mechanical properties of polyvinyl alcohol (PVA) and poly(methyl methacrylate) (PMMA)-matrix composites reinforced by functionalized few-layer graphene (FG) have been evaluated using the nano-indentation technique. A significant increase in both the elastic modulus and hardness is observed with the addition of 0.6 wt% of graphene. The crystallinity of PVA also increases with the addition of FG. This and the good mechanical interaction between the polymer and the FG, which provides better load transfer between the matrix and the fiber, are suggested to be responsible for the observed improvement in mechanical properties of the polymers.

Advances in nano-scaled biosensors for biomedical applications

Recently, a growing amount of attention has been focused on the utility of biosensors for biomedical applications. Combined with nanomaterials and nanostructures, nano-scaled biosensors are installed for biomedical applications, such as pathogenic bacteria monitoring, virus recognition, disease biomarker detection, among others. These nano-biosensors offer a number of advantages and in many respects are ideally suited to biomedical applications, which could be made as extremely flexible devices, allowing biomedical analysis with speediness, excellent selectivity and high sensitivity. This minireview discusses the literature published in the latest years on the advances in biomedical applications of nano-scaled biosensors for disease bio-marking and detection, especially in bio-imaging and the diagnosis of pathological cells and viruses, monitoring pathogenic bacteria, thus providing insight into the future prospects of biosensors in relevant clinical applications.

Reduction of Permittivity in Epoxy Nanocomposites at Low Nano-filler Loadings

Experimental studies reveal a reduction in the values of permittivity for epoxy nanocomposites; at low filler loadings as compared to neat epoxy over a wide frequency range. This permittivity reduction is attributed to the interaction dynamics between nanoparticles: and epoxy chains at the interface region and interestingly, this interaction has also been found to influence the glass transition temperatures (T-g) of the examined nanocomposite systems. Accordingly, a dual nanolayer interface model for an epoxy based nanocomposite system is analyzed to explain the obtained permittivity characteristics.

Graphene with patterned fluorination: Morphology modulation and implications

Recent years have witnessed a large volume of works on the modification of graphene; however, an understanding of the associated morphology or mechanical properties changes is still lacking, which is vital for its engineering implementation. By taking the C4F fluorination as an example, we find that the morphology of both graphene sheet (GS) and graphene nanoribbon (GNR) can be effectively tailored by fluorination patterning via molecular dynamics simulations. The fluorine atom produces out-of-plane forces which trigger several intriguing morphology changes to monolayer graphene, including zigzag, folded, ruffle, nanoscroll, and chain structures. Notably, for multilayer GNR, the delamination and climbing phenomena of the surface layer are observed. Further studies show that the fluorination pattern can also be utilized to modulate the mechanical properties of graphene, e.g., about 40% increase of the effective yield strain is observed for the examined GNR with fluorination patterns. This study not only demonstrates the significant impacts on the morphology of graphene from fluorination but also suggests an effective avenue to tailor the morphology and thus mechanical properties of GS and GNR.

Efficacy of nano-silver in alleviating bacteria-related blockage in cut rose cv. Movie Star stems

Postharvest treatments with nano-silver (NS) significantly improve water relations and therefore prolong the vase life of several cut flowers, including rose (Rosa hybrida cv. Movie Star). The efficacy of NS in alleviating bacterial related blockage in the stem-ends of cut cv. Movie Star was further investigated. Four dominant bacteria strains Pseudomonas fluorescens, Aeromonas sp., Comamonas acidovorans and Chryseomonas luteola were isolated from the stem-ends of cut roses. High numbers of the isolated bacteria at 10 8colony forming unitsmL -1 vase solution led to a sharp reduction in vase life, flower fresh weight, and water uptake. In vitro assessments of the antibacterial activity of NS against the four bacterial strains was >80% at 5mgL -1 and nearly 100% at 50mgL -1. Bacterial blockage in the stem-ends of cut cv. Movie Star roses with and without NS pulse treatments was assessed during the vase period using scanning electron microscopy. Following a 50mgL -1 NS pulse treatment, there were few bacterial cells on the cut surface of the stems even on day 7. Moreover, no obvious bacterial blockage was observed inside the xylem vessels. In contrast, the cut surface of control stems was covered with bacteria and associated amorphous substances, and numerous bacteria were found in the xylem vessels. © 2012 Elsevier B.V.

Effects of three different nano-silver formulations on cut Acacia holosericea vase life

The relative efficacies of three chemically different nano-silver (NS) formulations were evaluated for their potential to extend the vase life of short-lived cut Acacia holosericea foliage. The novel proprietary formulations were neutral NS, acidic NS and ionic NS. They were characterised in terms of particle size, pH value, colour and odour. The NS treatments were applied as vase (lower concentrations) or pulse (higher concentrations) solutions. Among the treatments compared, neutral NS as a 4 mg L-1 vase solution or as a 40 mg L-1 24 h pulse treatment and acidic NS as a 0.5 mg L-1 vase solution or as a 5 mg L-1 24 h pulse treatment significantly (P <= 0.05) extended the vase life of A. holosericea. Vase life extensions over the deionised water (DI) controls were associated with better maintenance of relative fresh weight and vase water uptake, suppression of bacterial growth in the vase water and stem-end, and delaying stem blockage. In contrast, ionic-NS applied as a 0.5 or 1 mg L-1 vase solution treatment or as a 5 or 10 mg L-1 pulse treatment caused severe phytotoxicity to cut A. holosericea stems. The results suggest that NS treatments, especially neutral NS and acidic NS pulse treatments, could be a potential postharvest technology for commercial application to cut A. holosericea. (C) 2011 Elsevier B.V. All rights reserved.

Study of Structural Stability and Electronic Structure of Nonstoichiometric CdS Nano Clusters from First Principles

Structural stability of small sized nonstoichiometric CdS nano clusters between zincblende and wurtzite structures has been investigated using first-principles density functional calculations. Our study shows that the relative stability of these two structures depends sensitively on whether the surface is S-terminated or Cd-terminated. The associated band gap also exhibits non-monotonic behavior as a function of cluster size. Our findings may shed light on contradictory reports of experimentally observed structures of CdS nano clusters found in the literature.

Can Nano Silicon Be Made Optically Active?

There has been a lot of effort to make Silicon optically active. In this work we examine two methods of generating nanocrystals of Silicon from bulk fragments. This approach of ours allows us to play with the shape of the nanocrystals and therefore the degeneracy of the conduction band minimum. We go on to examine whether similar sized particles with different shapes have the same physical properties, and finally whether Silicon may be rendered optically active by this route. While we do find that similar sized particles with different shapes may have different band gaps, this route of modifying the degeneracy of the conduction band minimum makes nano Si slightly optically active.

Photocatalytic activity of Ag-substituted and impregnated nano-TiO2

Ag-substituted (Ag sub) and Ag-impregnated (Ag imp), anatase phase nano-TiO2 have been synthesized by solution combustion technique and reduction technique, respectively. The catalysts were characterized extensively by powder XRD, TEM, XPS, FT-Raman, UV absorption, FT-IR, TGA, photoluminescence, BET surface area and isoelectric pH measurements. These catalysts were used for the photodegradation of dyes and for the selective photooxidation of cyclohexane to cyclohexanone. The photoactivities of the combustion-synthesized catalysts were compared with those of commercial Degussa P 25 (DP 25) TiO2, and Ag-impregnated DP 25 (Ag DP). For the photocatalytic degradation of dyes, unsubstituted combustion-synthesized TiO2 (CS TiO2) exhibited the highest activity, followed by 1% Ag imp and 1% Ag sub. For the photoconversion of cyclohexane, the total conversion of cyclohexane and the selectivity of cyclohexanone followed the order: 1% Ag sub > DP 25 > CS TiO2 > 1% Ag imp > 1% Ag DP. The kinetics of the photodegradation of dyes and of the photooxidation of cyclohexane were modeled using Langmuir–Hinshelwood rate equation and a free radical mechanism, respectively, and the rate coefficients were determined. The difference in activity values of the catalysts observed for these two reactions and the detailed characterization of these catalysts are described in this study.

Light and heat induced interdiffusion in Sb/As2S3 nano-multilayered film

The light and heat induced changes in the optical band gap of Sb/As2S3 nanomultilayered chalcogenide film has been studied. Even though the changes in optical bandgap are attributed to the light and heat induced interdiffusion, the diffusional intermixing between the layers is rather different with light and heat. The observed difference in the light and heat induced interdiffusion is due to unequal diffusion coefficients of light and heat predicted by thermal spike model.