The validity of the strong perfect-graph conjecture for (K4−e)-free graphs

Berge's strong perfect-graph conjecture states that a graph is perfect iff it has neither C_2n+1 nor $\text{C}{}_{\mathrm{2n+1}}$, n ≥ 2 as an induced subgraph. In this note we establish the validity of this conjecture for (K₄?e)-free graphs.     

Nuclease activity of 2-substituted heteroaromatic thiosemicarbazone and semicarbazone copper(II) complexes

Copper(II) Schiff base complexes derived from furan-2-carboxaldehyde, 2-furylmethyl ketone, thiophene-2-carboxaldehyde and methyl-2-thienyl ketone with semicarbazide and thiosemicarbazide have been prepared and characterized by analytical, i.r., electronic, e.s.r. and c.v. spectral data. The electronic spectral d–d band position varies from 744–415nm in pyridine and 872–371nm in DMF. E.s.r. g values lie between 2.1439 and 2.3149 at LNT. All complexes undergo quasi-reversible one-electron electrochemical reduction (Cu^III/Cu^II) in the 0.42–0.52V potential range. The electron transfer is much faster in thiosemicarbazone complexes compared to semicarbazone complexes. All these copper(II) complexes showed increased nuclease activity in presence of oxidant.     

Facile synthesis of nickel cobalt sulfide nano flowers for high performance supercapacitor applications

A facile synthesis of nickel cobalt sulfide (NCS) nanoflowers have been deposited successfully onto binder free 3D nickel foam electrodes using simple successive ionic layer adsorption and reaction (SILAR) method for supercapacitor applications. The obtained NCS nanoflowers manifest ultrahigh specific capacitance of 1899 F g^?1 at a scan rate of 5 mV s^?1. The NCS nanoflowers exhibit a prominent energy density of 55.16 Wh kg^?1 at power density of 495 W kg^?1 and superior cyclic stability of 94% after 10000 cycles. In addition, the asymmetric supercapacitor (ASC) device is fabricated using NCS nanoflower as positive and reduced graphene oxide (rGO) as negative electrodes, respectively. The ASC (NCS//rGO) delivered good capacity with excellent energy and power densities within 1.6 V wider potential window. Hence, NCS nanoflowers are an outstanding material for energy storage applications in near future.     

Rotational-echo double-resonance NMR distance measurements for the tubulin-bound Paclitaxel conformation

The important anticancer drug Taxol (paclitaxel, PTX) owes its unique activity to its ability to bind to tubulin in a stoichiometric ratio and promote its assembly into microtubules. The conformation of the microtubule-bound drug has been the focus of numerous research efforts, since the inability of polymerized tubulin to form crystals precludes structure proof by X-ray crystallography. Likewise, although the alpha,beta-tubulin dimer structure has been solved by electron crystallography, the 3.7 A resolution is too low to permit direct determination of either ligand conformation or binding pose. In this article, we present experimental results from 2H{19F} REDOR NMR that provide direct confirmation that paclitaxel adopts a T-shaped conformation when it is bound to tubulin.     

Wigner distribution of elliptical quantum optical vortex

We calculate the Wigner quasiprobability distribution function of the quantum elliptical vortex in elliptical beam (EEV), produced by coupling squeezed coherent states of two modes. The coupling between the two modes is performed by using beam splitter (BS) or a dual channel directional coupler (DCDC). The quantum interference due to the coupling between the two modes promises the generation of controlled entanglement for quantum computation and quantum tomography.     

Relative performance of a vibratory energy harvester in mono- and bi-stable potentials

Motivated by the need for broadband vibratory energy harvesting, many research studies have recently proposed energy harvesters with nonlinear characteristics. Based on the shape of their potential function, such devices are classified as either mono- or bi-stable energy harvesters. This paper aims to investigate the relative performance of these two classes under similar excitations and electric loading conditions. To achieve this goal, an energy harvester consisting of a clamped-clamped piezoelectric beam bi-morph is considered. The shape of the harvester's potential function is altered by applying a static compressive axial load at one end of the beam. This permits operation in the mono-stable (pre-buckling) and bi-stable (post-buckling) configurations. For the purpose of performance comparison, the axial load is used to tune the harvester's oscillation frequencies around the static equilibria such that they have equal values in the mono- and bi-stable configurations. The harvester is subjected to harmonic base excitations of different magnitudes and a slowly varying frequency spanning a wide band around the tuned oscillation frequency. The output voltage measured across a purely resistive load is compared over the frequency range considered. Two cases are discussed; the first compares the performance when the bi-stable harvester has deep potential wells, while the second treats a bi-stable harvester with shallow wells. Both numerical and experimental results demonstrate the essential role that the potential shape plays in conjunction with the base acceleration to determine whether the bi-stable harvester can outperform the mono-stable one and for what range of frequencies. Results also illustrate that, for a bi-stable harvester with shallow potential wells, super-harmonic resonances can activate the inter-well dynamics even for a small base acceleration, thereby producing large voltages in the low frequency range.     

Glycoside bond formation via acid-base catalysis

Acid-base catalyzed glycosyl donor and then glycosyl acceptor activation with phenylboron difluoride or diphenylboron fluoride permits hydrogen bond mediated intramolecular S(N)2-type glycosidation in generally high anomeric selectivity.     

Asymmetric synthesis of tertiary and quaternary allyl- and crotylsilanes via the borylation of lithiated carbamates

Tertiary allyl- or crotylsilanes have been prepared in high er and dr via the lithiation-borylation reaction of alkyl carbamates with silaboronates. Using a related strategy, quaternary allylsilanes could be accessed in similarly high er.     

Streamer-Like Electrical Discharges in Water: Part I. Fundamental Mechanisms

Electrical discharge plasma formed in liquid water is under intensive investigation for many possible applications in biomedical, environmental and chemical engineering as well as for general scientific issues in plasma chemistry and other engineering applications. The subject of pulsed breakdown of water has additionally begun to assume importance due to growing interest in decontamination, purification of water containing chemical impurities and industrial sludge, and also in the emerging area of bio-electrics. This review paper focuses on the plasma physics (Part I) and chemistry of electrical discharges in liquid water and the chemical effects of plasmas on the degradation of organic molecules (Part II). This part discusses dielectric liquid breakdown and its mechanisms, streamer propagation and the effect of electrode polarity on streamer dynamics.     

ALOHA: a novel probability fusion approach for scoring multi-parameter drug-likeness during the lead optimization stage of drug discovery

Automated lead optimization helper application (ALOHA) is a novel fitness scoring approach for small molecule lead optimization. ALOHA employs a series of generalized Bayesian models trained from public and proprietary pharmacokinetic, absorption, distribution, metabolism, and excretion, and toxicology data to determine regions of chemical space that are likely to have excellent drug-like properties. The input to ALOHA is a list of molecules, and the output is a set of individual probabilities as well as an overall probability that each of the molecules will pass a panel of user selected assays. In addition to providing a summary of how and when to apply ALOHA, this paper will discuss the validation of ALOHA’s Bayesian models and probability fusion approach. Most notably, ALOHA is demonstrated to discriminate between members of the same chemical series with strong statistical significance, suggesting that ALOHA can be used effectively to select compound candidates for synthesis and progression at the lead optimization stage of drug discovery.