Au–Pt alloy nanocrystals incorporated in silica films

Au, Pt and Au–Pt alloy nanocrystals have been prepared in thin SiO2 film matrices by sol–gel spin-coating, followed by heating at 450°C in 10% H2–90% Ar. X-Ray diffraction patterns reveal that the Au and Au–Pt nanocrystals have a preferential (111) orientation. Upon increasing the Pt concentration, part of the Pt does not alloy with Au, but instead forms a shell around the Au–Pt alloy core. The alloy composition itself goes up to Au(50):Pt(50), and the Pt shells are formed around the alloy above an alloy composition of Au(75):Pt(25). The surface plasmon resonance (SPR) band at 544 nm of Au gradually disappears due to the formation of Au–Pt alloys and core–shell structures

Efficient energy storage in mustard husk derived porous spherical carbon nanostructures

A. P. thanks CSIR India for a senior research fellowship (Award No. 31/15(136)/2017-EMR-I). S. C. thanks UGC, India for a research fellowship (Award No. F.2-44/2011(SA-I)).An environment-friendly synthesis of highly porous spherical carbon nanostructures (PSCNs), in situ doped with N and S, from mustard seed waste has been accomplished. The synthesised PSCNs have an interconnected network, abundant active interfaces, heteroatom rich content, and notably high porosity/surface area which are favourable for fast ion transport and efficient charge storage. This active material (PSCN), when employed as a lithium-ion battery (LIB) half-cell anode, shows a specific charge capacity of 714 mA h g−1 at a current density of 100 mA g−1 even after 550 cycles with 112% capacity retention and high restoration capability. Furthermore, PSCN//LiFePO4 full cell LIBs show an excellent performance with a highly reversible capacity of ∼195 mA h g−1 at a current density of 50 mA g−1 for 400 cycles. The PSCN electrode also exhibited a specific capacitance of 257.8 F g−1 at a current density of 0.1 A g−1 with ∼93% capacity retention after 10 000 cycles, when used as an electrochemical supercapacitor in aqueous 3 M KOH electrolyte. This work shows the preparation of high value and advanced carbon nanostructured material from renewable bio-mass waste for high-performance electrochemical energy storage applications.Publisher PDFPeer reviewe

Zirconia based superhydrophobic coatings on cotton fabrics exhibiting excellent durability for versatile use

A fluorinated silyl functionalized zirconia was synthesized by the sol-gel method to fabricate an extremely durable superhydrophobic coating on cotton fabrics by simple immersion technique. The fabric surfaces firmly attached with the coating material through covalent bonding, possessed superhydrophobicity with high water contact angle approximate to 163 +/- 1 degrees, low hysteresis approximate to 3.5 degrees and superoleophilicity. The coated fabrics were effective to separate oil/water mixture with a considerably high separation efficiency of 98.8 wt% through ordinary filtering. Presence of highly stable (chemically and mechanically) superhydrophobic zirconia bonded with cellulose makes such excellent water repelling ability of the fabrics durable under harsh environment conditions like high temperature, strong acidic or alkaline solutions, different organic solvents and mechanical forces including extensive washings. Moreover, these coated fabrics retained self-cleanable superhydrophobic property as well as high water separation efficiency even after several cycles, launderings and abrasions. Therefore, such robust superhydrophobic ZrO2 coated fabrics have strong potential for various industrial productions and uses

Comparison of analyses of the QTLMAS XII common dataset. II: genome-wide association and fine mapping

As part of the QTLMAS XII workshop, a simulated dataset was distributed and participants were invited to submit analyses of the data based on genome-wide association, fine mapping and genomic selection. We have evaluated the findings from the groups that reported fine mapping and genome-wide association (GWA) efforts to map quantitative trait loci (QTL). Generally the power to detect QTL was high and the Type 1 error was low. Estimates of QTL locations were generally very accurate. Some methods were much better than others at estimating QTL effects, and with some the accuracy depended on simulated effect size or minor allele frequency. There were also indications of bias in the effect estimates. No epistasis was simulated, but the two studies that included searches for epistasis reported several interacting loci, indicating a problem with controlling the Type I error rate in these analyses. Although this study is based on a single dataset, it indicates that there is a need to improve fine mapping and GWA methods with respect to estimation of genetic effects, appropriate choice of significance thresholds and analysis of epistasis

Techno-economic feasibility study of different WDM/TDM PON architectures

Introducing a WDM dimension on the top of a TDM PON system is a natural evolution to increase the capacity of the network, but this can also offer additional flexibility options. Different WDM/TDM PON flavours are compared to each other in terms of flexibility at the remote node and/or the ONU side. The considered architectures are then evaluated from a techno-economic point of view for a 10G technology, taking into account reasonable target costs for the optical components. In general the increased flexibility at the remote nodes has shown to have a limited influence on the cost, which opens good perspectives for more advanced WDM/TDM PON technologies. However, adding full flexibility in the optical layer at the ONU side will be too costly in the coming years, as the cost-per-user can be doubled or even more, compared to a fully ldquostaticrdquo solution

The efficiency of mapping of quantitative trait loci using cofactor analysis in half-sib design

This simulation study was designed to study the power and type I error rate in QTL mapping using cofactor analysis in half-sib designs. A number of scenarios were simulated with different power to identify QTL by varying family size, heritability, QTL effect and map density, and three threshold levels for cofactor were considered. Generally cofactor analysis did not increase the power of QTL mapping in a half-sib design, but increased the type I error rate. The exception was with small family size where the number of correctly identified QTL increased by 13% when heritability was high and 21% when heritability was low. However, in the same scenarios the number of false positives increased by 49% and 45% respectively. With a liberal threshold level of 10% for cofactor combined with a low heritability, the number of correctly identified QTL increased by 14% but there was a 41% increase in the number of false positives. Also, the power of QTL mapping did not increase with cofactor analysis in scenarios with unequal QTL effect, sparse marker density and large QTL effect (25% of the genetic variance), but the type I error rate tended to increase. A priori, cofactor analysis was expected to have higher power than individual chromosome analysis especially in experiments with lower power to detect QTL. Our study shows that cofactor analysis increased the number of false positives in all scenarios with low heritability and the increase was up to 50% in low power experiments and with lower thresholds for cofactors

Synthesis of equimolar Pd-Ru alloy nanoparticles incorporated mesoporous alumina films: A high performance reusable film catalyst

We report the synthesis of equimolar Pd-Ru alloy nanoparticles (NPs) incorporated mesoporous alumina films (Pd-Ru/MAF) by the sol-gel route. The synthetic strategy involves homogeneous mixing of the Pd2+ and Ru3+ ions in the alumina sol containing P123 micelles. Dip-coated films, prepared on ordinary glass substrates, were thermally reduced at a relatively lower temperature (500 degrees C) to generate equimolar Pd-Ru/MAF with a nominal molar composition of Pd:Ru:AlO1.5=2:2:96. Electron microscopy studies revealed uniformly distributed Pd-Ru alloy NPs in a mesoporous alumina-alumina sphere composite film matrix. The P123/alumina nanocomposite acted as an excellent breeding medium to form Pd-Ru (similar to 1:1) alloy NPs despite the poor miscibility of the two metals. Pd-Ru/MAF showed excellent catalytic performances with highest normalized rate constant values (5.43 X 10(14) min(-1) mol(-2)) and possessed good reusability compared to the corresponding monometallic analogues in the reduction of aqueous 4-nitrophenol in the presence of NaBH4 at 25 degrees C

Carbon Dots from a Single Source Exhibiting Tunable Luminescent Colors through the Modification of Surface Functional Groups in ORMOSIL Films

A simple strategy to fabricate carbon dots (CDs) incorporated organically modified silica (ORMOSIL) films exhibiting tunable tricolor emission has been accomplished. First, the green-emitting CDs with excitation-independent nature and high quantum yield were prepared from o-phenylenediamine in ethanol by solvothermal method. These CDs after purification were dispersed in ORMOSIL sol, and their photoluminescence wavelengths were tuned to three intense luminescent colors (orange, yellow, and green) by adjusting the pH of the sol. It was observed that with pH tuning the functional groups residing on surface-passivated CDs are undergoing chemical modifications, and accordingly the PL emission of CDs in ORMOSIL sol systematically changes to orange, yellow, and green emissions, respectively. Interestingly, the structure of such surface-modified CDs can be well-preserved in the ORMOSIL film-matrix with substantial concentration to obtain the above tricolor luminescent films on glass. A systematic X-ray photoelectron spectroscopy study revealed that the blue shifting in triluminous films (from 560 to 510 nm) with pH increment was originated due to the deprotonation of the surface groups (-CONH- -> -CO(N-)-; -NH3+ -> -NH2) associated with the CDs. The plausible mechanism behind the rationalization of pH-triggered engineering of surface-passivated CD-ORMOSIL sols and their confinement in films has been explored

Crystal structure tailoring of Au–Cu alloy NPs using the embedding film matrix as template

Au–Cu alloy nanoparticles (NPs) were grown in three different dielectric film matrices by the sol–gel method in order to see the influence of the embedding matrices on the crystal structure of the alloy NPs. The chosen film matrices were TiO2 (anatase; tetragonal), ZrO2 (cubic) and SiO2 (amorphous). Au and Cu salts (1 : 1 molar ratio) doped MO2 (M = Ti, Zr and Si) sols were prepared keeping the total metal concentration same (M : MO2 = 1 : 9) in all the three cases, and used them for coating deposition on silica glass substrates. Heat-treatment of the films in air at 500 °C resulted in removal of organics, formation of metallic Au NPs and matrix crystallization (tetragonal and cubic in cases of TiO2 and ZrO2, respectively; SiO2 remained amorphous). Further heat-treatment in reducing atmosphere (10% H2–90% Ar/500 °C) induced the reduction of Cu ions with simultaneous formation of Au–Cu alloy NPs. In cases of TiO2 and ZrO2 films, formation of equiatomic Au1Cu1 alloy NPs were completed whereas Au3Cu1 alloy NPs was found to be formed in SiO2 under the similar experimental conditions. Structural analyses confirmed the formation of ordered face centred tetragonal (fct) and disordered face centred cubic (fcc) Au–Cu NPs in cases of TiO2 and ZrO2 matrices, respectively. Thus tetragonal (anatase TiO2) and cubic (ZrO2) structures of the embedding film matrices acted as templates to nucleate and subsequent growth of the Au–Cu order (fct) and disorder (fcc) alloy nanocrystals, respectively. Cubic Au3Cu1 alloy NPs was also formed in amorphous SiO2; however, without any structural influence of the matrix alloy formation could not be completed at such a low temperature

Synthesis of amine functionalized graphite nanosheets and their water-soluble derivative for drug loading and controlled release

A facile route to synthesize amine (–NH2) functionalized graphite nanosheets (AFGNS) by 2-step controlled chemical modification of microcrystalline graphite is described. The method begins with nitration by mixed acid (HNO3 : H2SO4 in 1 : 1 v/v ratio), followed by reduction with Na2S to form AFGNS. The AFGNS was reacted with carboxylic acid-terminated polyethylene glycol (PEG) chains (MeO–mPEG–COOH, MW = 5000 Da) in the presence of a carbodiimide coupling agent to obtain a water-soluble PEGylated AFGNS (P-AFGNS) composite. Anticancer drug doxorubicin (DOX) was loaded on this composite with a loading capacity of 0.296 mg mg−1 for an initial concentration of 0.232 mg mL−1 DOX and 0.136 mg mL−1 of P-AFGNS and the release of DOX from this water-soluble DOX loaded P-AFGNS composite at two different temperatures was found to be strongly pH dependent