Au and Au-Ag bimetallic nanoparticles synthesized by using 12-3-12 cationic Gemini surfactant as template

A seed-growth method has been applied to synthesize gold (Au) and Au-silver (Ag) bimetallic nanoparticles (NP) by using 12-3-12, a cationic Gemini surfactant, as a capping agent as well as micellar template. A systematic increase in the [12-3-12] from pre- to post-micellar region (up to 5 times the critical micelle concentration, cmc) produces Au NP from spherical to large plate like structures. Keeping [12-3-12] constant (equal to 1 / 2 cmc) and increasing ascorbic acid (AA) concentration lead to the formation of core shell type Au-Ag bimetallic NP. At maximum AA concentration (i.e. [AA] = 5.6 mM), fused bimetallic Au-Ag NP are obtained. The anisotropic growth of such materials is a key factor for various applications in nanotechnology.     

Differential Effects of STCH and Stress-Inducible Hsp70 on the Stability and Maturation of NKCC2

Mutations in the Na-K-2Cl co-transporter NKCC2 lead to type I Bartter syndrome, a life-threatening kidney disease. We previously showed that export from the ER constitutes the limiting step in NKCC2 maturation and cell surface expression. Yet, the molecular mechanisms involved in this process remain obscure. Here, we report the identification of chaperone stress 70 protein (STCH) and the stress-inducible heat shock protein 70 (Hsp70), as two novel binding partners of the ER-resident form of NKCC2. STCH knock-down increased total NKCC2 expression whereas Hsp70 knock-down or its inhibition by YM-01 had the opposite effect. Accordingly, overexpressing of STCH and Hsp70 exerted opposite actions on total protein abundance of NKCC2 and its folding mutants. Cycloheximide chase assay showed that in cells over-expressing STCH, NKCC2 stability and maturation are heavily impaired. In contrast to STCH, Hsp70 co-expression increased NKCC2 maturation. Interestingly, treatment by protein degradation inhibitors revealed that in addition to the proteasome, the ER associated degradation (ERAD) of NKCC2 mediated by STCH, involves also the ER-to-lysosome-associated degradation pathway. In summary, our data are consistent with STCH and Hsp70 having differential and antagonistic effects with regard to NKCC2 biogenesis. These findings may have an impact on our understanding and potential treatment of diseases related to aberrant NKCC2 trafficking and expression.     

Cationic surfactant-selective potentiometric sensors based on neutral ion-pair carrier complexes

Poly(vinyl chloride) (PVC) membrane electrodes to determine monomer concentrations of tetradecyltrimethylammonium ion (TTA⁺) and hexadecylpyridinium ion (HPy⁺) based on neutral ion-pair carrier complexes of tetradecyltrimethylammonium dodecyl sulfate (TTA⁺-DS⁻) and hexadecylpyridinium dodecyl sulfate (HPy⁺-DS⁻), respectively, are reported here. The electrodes exhibit a Nernstian slope of 59 mV per decade for TTA⁺ and a sub-Nernstian slope of 34.5 mV per decade for HPy⁺ ions. The TTA⁺ ion-selective electrode (ISE) and the HPy⁺-ISE can determine the monomer units down to concentrations as low as 4.0×10⁻⁴M and 1.66×10⁻⁵ M, respectively. The effect of various additives, such as the anionic polyelectrolyte sodium dextran sulfate and macrocyclic β-cyclodextrin, on the surface activity exhibited by the cationic surfactants TTA⁺-DS⁻ and HPy⁺-DS⁻, in the presence of background concentrations of NaCl was also examined with surfactant-selective sensors. The Gibbs free energy of micelle formation (ΔG _m ) of both surfactants in the presence of various additives was calculated and found to be less favorable with respect to an increase in the amount of additives due to less availability of cationic surfactant monomer units. The ion-pair complexes TTA⁺-DS⁻ and HPy⁺-DS⁻ were found to behave as selective carrier compounds in PVC membranes in determining the concentration of monomer units of both TTA⁺ and HPy⁺, respectively. The proposed sensors worked well at a fairly acidic pH of 1–6.5 with response time of 60 s. The sensors responded well to the surfactant ions even in the presence of additives at lower concentration. The lifetime of the sensors is 3 mon.     

Synthesis and physicochemical studies of some new amphoteric ion exchangers

Some new amphoteric ion exchangers have been synthesized by condensing salicylic acid, p-hydroxybenzoic acid, sulfosalicylic acid, gallic acid, 3-hydroxy-2-naphthoic acid, β-resorcylic acid, and resacetophenone with epichlorohydrin employing ethylenediamine as a crosslinking agent. Some of the physicochemical properties, such as moisture content, true density, apparent density, void volume fraction, concentration of ionogenic groups, exchange capacity, rate of exchange, pH-titration curves, pK values, isoionic point, thermal stability, oxidation resistance, and swelling behavior in different solvents, have been investigated.     

Impedance measurements on some doped MnO2 electrodes in H2SO4 electrolyte

A.c. impedance behaviour of MnO₂ and doped -MnO₂ electrodes in H₂SO₄ medium was assessed with a view to explaining the mechanism of the discharge behaviour of MnO₂ electrodes in 4m H₂SO₄ electrolyte. The electrodes used in this work appear to be intermediate cases of planar and porous electrodes as the angles, , made by the low frequency part with the real axis are found to be in the range (30–60°). The Nyquist plots and the Randle plots tend to reinforce the observation made by Tye that the capacity yield is essentially diffusion controlled. The depression and flattening of semi-circles observed reveals a link with the heterogeneity of the planar electrode and with the porosity of the pitted electrode. The deviation from a 45° angle made by the low frequency part with the real axis may either be explained by the roughness of the electrode surface or the shallow pores on the surface of the electrodes; in other words due to the difference between the apparent and true surface areas. The double layer capacitance values of the electrodes seem to subsume adsorption capacitances and diffusion factors. Hence, the relative increase in magnitude. The electrodes appear to behave like planar electrodes when 10 µF is introduced into the circuit as a parallel capacitance since angles 0 vary between 40–58°. The undoped -MnO₂ electrode, as well as those prepared from Li-MnO₂, Ag-MnO₂, and I.C.8, appear to be planar electrodes.     

On the Computational Complexity of Consumer Decision Rules

A consumer entering a new bookstore can face more than 250,000alternatives. The efficiency of compensatory and noncompensatory decisionrulesfor finding a preferred item depends on the efficiency of their associatedinformation operators. At best, item-by-item information operators lead tolinear computational complexity; set information operators, on the other hand,can lead to constant complexity. We perform an experiment demonstrating thatsubjects are approximately rational in selecting between sublinear and linearrules. Many markets are organized by attributes that enable consumers toemploya set-selection-by-aspect rule using set information operations. In cyberspacedecision rules are encoded as decision aids.     

Probing the influence of superhydrophobicity and mixed wettability on droplet displacement behavior

The importance of fundamental understanding of droplet dynamics and the concomitant implications of wall wettability are critical in the emergent science and technology areas including digital microfluidics and clean energy conversion. In this work, mesoscopic illustration, based on the two-phase lattice Boltzmann model, of droplet dynamics in a microchannel is presented in order to unveil the role of superhydrophobicity and mixed wettability. The impact of critical physicochemical determinants, including capillary number and droplet size, is explored in the context of droplet–wettability interactions. Temporal evolution of wetted length and wetted area for a combination of wettability scenarios is furnished in detail in order to elucidate the droplet displacement dynamics. Capillary number plays an important role with disparate droplet behavioral patterns stemming from superhydrophobic and mixed-wet wall characteristics.     

Fabrication and machining of ceramic composites — A review on current scenario

Ceramic matrix composites (CMCs) are the best-suited material for various engineering application due to their superior properties. The different processing methods involved in the fabrication and machining of these CMCs are a center for attraction to researchers and industrial society. This review article primarily focuses on the development of different processing methods and machining methods for ceramic matrix composites since the last few years. Out of these fabrication methods, powder metallurgy emerged as a most promising and cost-effective technique. In addition, electric discharge machining (EDM) has proved to be time saving, cost effective, and capable of machining complex shapes in composites. At the end, challenges in the processing and machining of ceramic matrix composites have been identified from the literature, and further benefits of microwave sintering and electric discharge machining of materials have been addressed in the paper.     

Performance Evaluation of Stacked Gate Oxide/High K Spacers Based Gate All Around Device Architectures at 10 nm Technology Node

Silicon - In this paper, we have done performance evaluation of different Gate All Around (GAA) FET device structures using gate-oxide stacking and spacers of different materials including dual and...