Synthesis,CMC Determination,Antimicrobial Activity and Nucleic Acid Binding of A Surfactant Copper(II) Complex Containing Phenanthroline and Alanine Schiff-Base

A new water-soluble surfactant copper(II) complex [Cu(sal-ala)(phen)(DA)] (sal-ala = salicylalanine, phen = 1,10-phenanthroline, DA = dodecylamine), has been synthesized and characterized by physico-chemical and spectroscopic methods. The critical micelle concentration (CMC) values of this surfactant–copper(II) complex in aqueous solution were obtained from conductance measurements. Specific conductivity data (at 303, 308, 313. 318 and 323 K) served for the evaluation of the temperature-dependent CMC and the thermodynamics of micellization (ΔG⁰m, ΔH⁰m and ΔS⁰m). The interaction of this complex with nucleic acids (DNA and RNA) has been explored by using electronic absorption spectral titration, competitive binding experiment, cyclic voltammetry, circular dichroism (CD) spectra, and viscosity measurements. Electronic absorption studies have revealed that the complex can bind to nucleic acids by the intercalative binding mode which has been verified by viscosity measurements. The DNA binding constants have also been calculated (K_b?=?1.2?×?10⁵ M^?1 for DNA and K_b?=?1.6?×?10⁵ M^?1 for RNA). Competitive binding study with ethidium bromide (EB) showed that the complex exhibits the ability to displace the DNA-bound-EB indicating that the complex binds to DNA in strong competition with EB for the intercalative binding site. The presence of hydrophobic ligands, alanine Schiff-base, phenanthroline and long aliphatic chain amine in the complex were responsible for this strong intercalative binding. The surfactant–copper (II) complex was screened for its antibacterial and antifungal activities against various microorganisms. The results were compared with the standard drugs, amikacin(antibacterial) and ketokonazole(antifungal).     

Thermodynamics of self-assembly of sodium octanoate: comparison with a fully fluorinated counterpart

The isotherms of conductivity of sodium octanoate were measured and the critical micelle concentration (cmc) and degree of ionization of the micelles, β, determined in a range of temperatures (273–343 K) above the Krafft point. The thermodynamic parameters, Gibbs free energy ΔG _m ⁰, enthalpy ΔH _m ⁰, and entropy ΔS _m ⁰ of micelle formation, were determined from polynomial adjustments of the temperature dependence of cmc and from a proposed thermodynamic model based on the works of Muller [1993, Langmuir, 9, 96] and Rodríguez et al. [2002, J. Colloid Interface Sci., 250, 438]. The increase in heat capacity upon micellization, ΔC _pm ⁰, was estimated from the parameters of the model and the enthalpy—entropy compensation phenomena discussed. Finally, for information on their structural differences, hence to understand their different behaviours, thermodynamic parameters are discussed, comparing the corresponding fluorocarbon compound. A remarkable shift in minimum temperature in the U-shaped curve of cmc versus temperature was found when hydrogen was substituted by fluorine in the hydrophobic chain of the surfactant. This behaviour is a consequence of the special characteristics of the fluorine substituent in the hydrophobic tail and was reflected in the thermodynamic parameters and in the enthalpy—entropy compensation parameters, presenting different intercepts at the same compensation temperature.     

Effect of Ethanol on the Partition Coefficient Of Cyclohexylacetate Between Bulk and Cetyltrjmethylammonium Bromide Micellar Pseudophases

Variation of the partition coefficient of cyclohexylacetate (CA) was studied by a differential absorption spectroscopic method as a function of ethanol and (CTAB) cetyltrimethylammoniumbromide concentrations. Approach used was based upon the pseudo-two phase model, including effect of ethanol concentrations on the critical micelle concentration (CMC) of CTAB. Ethanol enhanced micelle formation of CTAB at concentrations below 1% by volume, had a slight inhibitory effect at higher concentrations and totally inhibited at a concentration above 15% by volume.

Various amounts of ethanol were used with a purpose of changing the solubility of CA in water. The differential absorbance (AA), was almost zero at low concentrations of CTAB, however an increase in AA began at a certain concentration of CTAB which can accordingly be assumed to be consistent with CMC of CTAB in the presence of ethanol. As CTAB concentration increased above CMC, ΔA reached a plateau. In this plateau, ΔA can reasonably be interpreted as the saturation of CA in micellar phase.

Plateau values of ΔA decreased with increasing ethanol concentration. This showed that the fraction of CA in the micellar phase depended on the ethanol concentration in terms of changing the solubility. Partition coefficients, K_c, were obtained from the plots of 1/ΔA against 1/[C_CA] +[C³ _m], which were linear in high CTAB concentrations. It was also seen that as ΔA, K_c decreased when the ethanol percentage were increased. In other words, the lower the solubility of CA in the bulk, the higher the partition coefficient.     

Investigation of ionization equilibria of L-aspartic and L-glutamic acids in water at a microscopic level by DFT method

The pK_a values of different dissociable groups of L-Aspartic and L-Glutamic acids in vacuo and in aqueous medium over a wide pH range have been estimated by DFT/B3LYP/6-31G(d) and 6-31G++(d,p) methods. For both the amino acids discrete water molecules (n?=?0, 3 and 6) have been used to get the first hydration sphere. Starting from a low pH, all possible tautomers resulting from each dissociation step are assumed to exist in a cyclic equilibrium. The structures of the species involved in the dissociation and tautomerization processes have been optimized in vacuo and also in aqueous medium considering H-bonded water molecules under the PCM formalism. For obtaining pK_a in aqueous medium the difference in Gibbs energy of the clusters H₃O⁺.mH₂O and (H₂O) _m+1 (m?=?an integer) is necessary and has been evaluated from computed literature data. Calculations reveal that in vacuo the neutral or less charged species predominate but in aqueous medium the zwitterionic or more chargeable forms contribute appreciably. The Gibbs energy changes for the microscopic cyclic equilibria have been estimated theoretically. These lead to overall (macroscopic) pK_a values for the ionization steps which are in good agreement with available experimental data for both the amino acids.     

Hyperfine patterns of infrared absorption lines of Ho3+ C4v centres in CaF2

Hyperfine structure is observed on several infrared transitions to the ⁵I₇ and ⁵I₆ multiplets of the Ho³⁺ C_4v centre in CaF₂. Particularly complex and detailed hyperfine structures are observed for transitions to the Y₃ level of the ⁵I₇ multiplet, which include the appearance of ΔI_z ≠ 0 transitions. The hyperfine lines of this level are satisfactorily accounted for by strong mixing of close-lying levels of this multiplet by the perpendicular hyperfine interaction, which leads to relaxation of the ΔI_z = 0 selection rule and a redistribution of the hyperfine intensities over many transitions. An excellent correspondence is found between the measured and simulated spectra.     

Some rigorous results for electromagnetic mass splittings in QCD

Written proved recently that m_π⁺m_π⁰. We note that this result is a consequence of the Green's function inequalities generalized to include EM as background fields. We also suggest that all ΔI = 2EM mass splittings can be proved to be positive.     

Mechanoluminescence Study of Europium Doped CaZrO<Subscript>3</Subscript> Phosphor

Behaviour displayed by mechanoluminescence (ML) in CaZrO₃:Eu³⁺ doped phosphors with variable concentration of europium ions are described. When the ML is excited impulsively by the impact of a load on the phosphors the ML intensity increases with time, attains a maximum value and then it decreases. In the ML intensity versus time curve, the peak increases and shifts towards shorter time values with increasing impact velocities. Sample was synthesized by combustion synthesis method with variable concentration of Eu³⁺ ions (0.1, 0.2, 0.5, 1, 1.5 mol%) and characterized by X-ray diffraction technique. The total ML intensity I_T is defined as the area below the ML intensity versus time curve. Initially I_T increases with impact velocity V₀ of the load and then it attains a saturation value for higher values of impact velocities which follow the relation I_T = I_T ⁰ exp.(?V_c/V₀) where I_T ⁰ and V_c are constants. Total ML intensity increases linearly with the mass of the phosphors for higher impact velocities. The ML intensity I_m, corresponding to the peak of ML intensity versus time curve increases linearly with the impact velocities. The time t_m, is found to be linearly related to 1000/V₀. The mechanoluminescence induced by impulsive excitation in europium doped CaZrO₃ phosphors plays a significance role in the understanding of biological sensors and display device application.     

NMR Self-diffusion Study of Amino Acid Ionic Liquids Based on 1-Methyl-3-Octylimidazolium in Water

In comparison with the conventional ionic liquids, water-miscible amino acid ionic liquids (AAILs) are considered as more biodegradable and biocompatible, less toxic, and as able to enhance the biomaterials stability. An application of some long-chain ionic liquids in catalysis, extraction, etc. requests the detailed analysis of ionic and water transport properties of their diluted aqueous solutions close to the area of its critical micelle concentration (cmc). In this work, the molecular transport properties of two 1-methyl-3-octylimidazolium-based AAILs, [C₈mim][Val], and [C₈mim][Leu] (with anions of l-Leucine or l-Valine), in the aqueous solutions were studied by measuring the self-diffusion coefficients and the solution’ viscosities in the temperature ranges 273–343 K at the AAIL’s concentrations below and above its cmc. The data on self-diffusion coefficients of water molecules and cations/anions of AAILs are discussed in terms of activation energies and of hydration effects. Above the cmc, the [C₈mim][Val] molecules demonstrate the strengthening effect on the solvent structure, while the molecules of [C₈mim][Leu] have structure-destructive effect. The results obtained for the relative dynamic viscosities show a decrease of micellar size with increasing temperature. In addition, it was found that the degrees of counterion binding for both AAILs are higher than for 1-methyl-3-octylimidazolium halides.     

Mixed micellization study of ibuprofen (sodium salt) and cationic surfactant (conventional as well as gemini)

Herein, we have studied the interaction between cationic surfactant (conventional [myristyltrimethylammonium bromide, MTAB] as well as gemini surfactant 1, 4‐butanediyl‐α, ω‐bis(dimethyltetradecylammonium bromide) (14‐4‐14)) and anti‐inflammatory sodium salt of ibuprofen (IBU) drug in aqueous solutions by using tensiometry method at 298.15 K. The means of the interaction of drugs by added foreign materials is of paramount importance in the drug delivery. Ibuprofen is used for the relief of pain, fever, and swelling. From this study we have evaluated different parameters, for example, critical micelle concentration (cmc), micellar mole fraction of mixed micelles/mixed interface (X₁^m/X₁^σ), micellar/surface interaction parameter (β^m/β^σ), activity coefficients (f₁^m/f₁^σ and f₂^m/f₂^σ) of the mixed micelles/mixed interface, excess Gibbs free energy of mixed monolayer/mixed micelle formation ( $\mathrm{\Delta }{G}_{\mathrm{ex}}^{\mathrm{\sigma }}$/ $\mathrm{\Delta }{G}_{\mathrm{ex}}^{\mathrm{m}}$), surface excess concentration (Γ_max) etc. and discussed in detail. The micellar interaction parameter (β^m) was determined from the critical micelle concentration values of the pure surfactant (MTAB/14‐4‐14) and IBU (cmc₁ and cmc₂) and the mixed system (cmc) using the Rubingh's model. In addition to this, various other parameters such as packing parameters of amphiphiles in the micelles (P), volume contribution of the hydrophobic chain (V₀), and its effective length (l_c), have also been calculated. The value of micellar mole fraction ( $X_1^{\mathrm{m}}$) is found to be more for IBU + 14‐4‐14 mixtures as compared to IBU + MTAB mixtures at lower mole fraction and vice versa at a higher mole fraction of surfactant. The ΔG^o_m and ΔG^o_ads values for all studied systems were found out to be negative, ie, micellization, as well as adsorption processes, are found to be energetically favorable.     

Comparison of effect of 5 MeV proton and Co-60 gamma irradiation on silicon NPN rf power transistors and N–channel depletion MOSFETs

NPN transistors and N-channel depletion metal oxide semiconductor field effect transistors (MOSFETs) were irradiated with 5?MeV protons and ⁶⁰Co gamma radiation in the dose ranging from 1?Mrad(Si) to 100?Mrad(Si). The different electrical characteristics of the NPN transistor such as Gummel characteristics, excess base current (ΔI_B), dc current gain (h_FE), transconductance (g_m), displacement damage factor (K) and output characteristics were studied as a function of total dose. The different electrical characteristics of N-channel MOSFETs such as threshold voltage (V_th), density of interface trapped charges (ΔN_it), density of oxide trapped charges (ΔN_ot), transconductance (g_m), mobility (µ) and drain saturation current (I_DSat) were studied systematically before and after irradiation in the same dose ranges. A considerable increase in the base current (I_B) and decrease in the h_FE, g_m and collector saturation current (I_CSat) were observed after irradiation in the case of the NPN transistor. In the N-channel MOSFETs, the ΔN_it and ΔN_ot were found to increase and V_th, g_m, µ and I_DSat were found to decrease with increase in the radiation dose. The 5?MeV proton irradiation results of both the NPN transistor and N-channel MOSFETs were compared with ⁶⁰Co gamma-irradiated devices in the same dose ranges. It was observed that the degradation in 5?MeV proton-irradiated devices is more when compared with the ⁶⁰Co gamma-irradiated devices at higher total doses.     

On the theory of the diffusion of gold into dislocated silicon wafers

The paper presents a theoretical study of the diffusion of gold into dislocated silicon wafers in terms of the kick-out mechanism Au _i Au _s +I, where Au _i , Au _s , andI mean Au interstitials, substitutional Au atoms, and Si self-interstitials, respectively. In agreement with experiments it is found that the Au _s concentration in the centre of a wafer,C _s ^m , increases with the durationt of the diffusion anneal according toC _s ^m =C _s ^eq (k ₀ t)^1/2 except forC _s ^m values in the vicinity of the solubility limitC _s ^eq of Au _s . Approximate analytical expressions fork ₀ as a function of the densityN _I of the dislocations acting asI sinks are given for the entire regime 0N_I<+t8.     

Lowest-lying tetra-quark hadrons in anisotropic lattice QCD

We present a detailed study of the lowest-lying hadrons in quenched improved anisotropic lattice QCD. Using the π π and diquark–antidiquark local and smeared operators, we attempt to isolate the signal for I(J ^P )=0(0⁺),2(0⁺) and 1(1⁺) states in two flavour QCD. In the chiral limit of the light-quark mass region, the lowest scalar 4q state is found to have a mass, m _4q ^I=0=927(12) MeV, which is slightly lower than the experimentally observed f ₀(980). The results from our variational analysis do not indicate a signature of a tetraquark resonance in I=1 and I=2 channels. After the chiral extrapolation the lowest 1(1⁺) state is found to have a mass m _4q ^I=1=1358(28) MeV. We analysed the static 4q potential extracted from a tetraquark Wilson loop and illustrated the behaviour of the 4q state as a bound state, unbinding at some critical diquark separation. From our analysis we conclude that the scalar 4q system appears as a two-pion scattering state and that there is no spatially-localised 4q state in the light-quark mass region.     

Organic/inorganic interfaced field-effect transistor properties with a novel organic semiconducting material

A novel 1,3,4-oxadiazole-substituted benzo[b]triphenylene was synthesized by three-step synthetic procedure and OFET device design was successfully designed after theoretical calculations made using Gaussian software. For investigating the field-effect properties of designed organic electronic device, a SiO₂ (300 nm) was thermally grown on p-Si wafer at 1000 °C as a dielectric layer and gate, source and drain contacts have been deposited using Au metal with physical vapour deposition. 1,3,4-Oxadiazole-substituted benzo[b]triphenylene was spin coated on the source and drain electrodes of our device, forming organic/inorganic interfaced field-effect transistors. Surface morphology and thin film properties were investigated using AFM. All electrical measurements were done in air ambient. The device showed a typical p-type channel behaviour with increasing negative gate bias voltage values. Our results have surprisingly shown that the saturation regime of this device has high mobility (μ_FET), excellent on/off ratio (I_on/I_off), high transconductance (g_m) and a small threshold voltage (V_Th). The values of μ_FET, I_on/I_off, g_m and V_Th were found as 5.02 cm²/Vs, 0.7 × 10³, 5.64 μS/mm and 1.37 V, respectively. These values show that our novel organic material could be a potential candidate for organic electronic device applications in the future.     

Effect of heat treatment procedure on magnetic and magnetocaloric properties of Ni43Mn46In11 melt spun ribbons

The effect of heat treatment on the structural, magnetic and magnetocaloric properties of Ni₄₃Mn₄₆In₁₁ melt-spun ribbons was systematically investigated using X-ray powder diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM), magnetic force microscope (MFM) and magnetic measurements. From the XRD studies, tetragonal and cubic phases were detected at room temperature for as-spun, quenched and slow-cooled ribbons. Furthermore, it was observed, upon annealing martensite transition temperatures increased when compared to the as-spun ribbon. To avoid magnetic hysteresis losses in the vicinity of the structural transition region, the magnetic entropy changes-ΔS _m of the investigated ribbons were evaluated from temperature-dependent magnetisation-M(T) curves on cooling for different applied magnetic fields. The maximum ΔS _m value was found to be 6.79 J kg^?1 K^?1 for the quenched ribbon in the vicinity of structural transition region for a magnetic field change of 50 kOe.     

Solvation thermodynamics of xylitol in water and in aqueous amino acids at 298.15 K

The scaled particle theory has been applied to calculate the free energy, ΔG_solv, enthalpy, ΔH_solv, and entropy, ΔS_solv of solvation for xylitol in water and in aqueous amino acids (glycine, alanine and valine) at 298.15 K. The solvation energy, enthalpy and entropy of xylitol are expressed in terms of their various ingredients. The results show that the interaction terms contribute favorably to the process of solvation. The results suggest that the cavity formation for accommodation of xylitol molecules in aqueous amino acids is an enthalpy‐dominated process. Furthermore, the investigated parameters indicate that xylitol–amino acid interactions follow the sequence: glycine alanine valine water. The findings of the present work may help to throw light on the role that xylitol can play to stabilize macromolecules like proteins in aqueous solutions. Copyright © 2012 John Wiley & Sons, Ltd.     

Chemical hardness-based prediction of the surface tension and enthalpy changes of sublimation for alkali halides

A new theoretical route employing the concept of chemical hardness has been developed to predict the surface tension γ and the changes of the standard enthalpies (CSEs) of sublimation Δ_sH⁰ of alkali halides. The values of these quantities have been calculated by means of the ratios η_M/V^1/3_m where η_M and V_m are the molecular hardness and molecular volume, respectively. The obtained results have been compared with those of previous theoretical models as well as with experimental data.     

Identities for Hypergeometric Integrals of Different Dimensions

Given complex numbers m₁, I₁ and nonnegative integers m₂, I₂, such that m₁+m₂ = I₁+ I₂, we define I₂-dimensional hypergeometric integrals I_a,b(z; m₁, m₂, I₁, I₂), a,b = 0,. . . ,min)(m₂,I₂), depending on a complex parameter z. We show that I_a,b(z;m₁, m₂,I₁, I₂) = I_a,b(z;I₁, I₂,m₁,m₂), thus establishing an equality of I₂ and m₂-dimensional integrals. This identity allows us to study asymptotics of the integrals with respect to their dimension in some examples. The identity is based on the ( _k, _k,) duality for the KZ and dynamical differential equations.Mathematics Subject Classifications (2000). 33C70, 33C80, 81R10     

Premicellar and micelle formation behavior of aqueous anionic surfactants in the presence of triphenylmethane dyes: protonation of dye in ion pair micelles

The premicellar and micelle formation behaviors of four cationic triphenylmethane dyes, viz, Pararosaniline (RN), Crystal violet (CV), Ethyl violet (EV), and Malachite green (MG), in aqueous anionic surfactant solutions of sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), and sodium dodecyl sulfonate (SDSN) have been studied by spectral and surface tension measurements. The study was carried out within a pH range where the dyes are stable in their quinoid forms. The dyes have been found to form dye–surfactant ion pairs (DSIPs) with the surfactants, at the surfactant concentrations well below their critical micelle concentration, CMC*. The DSIPs behave like nonionic surfactants and form an air–water interfacial monolayer. The DSIPs have a lower critical micelle concentration (CMC_IP), greater efficiency, and lower effectiveness than the corresponding pure surfactants. As the surfactant concentration is increased below the CMC*, the DSIPs start forming micelles of their own where the dye gets protonated and exists as a protonated dye–surfactant ion pair (PDSIP) in the ion pair micelles. As the concentration of the surfactant exceeds the CMC* of the pure surfactant, the protonation reverses gradually with the dye remaining in the micelles in solubilized form and the DSIPs in the air–water interfacial monolayer are replaced by pure surfactants. The distorted helical isomeric form (isomer B) of the dyes is favored in the PDSIPs. Copyright © 2009 John Wiley & Sons, Ltd.     

Nonleptonic Interactions of Kaons in the Quark Confinement Model

Nonleptonic, electromagnetic decays of K-mesons and K°–K̄° transition are treated with the effective Hamiltonians with ΔS = 1, 2. Matrix elements of four-quark operators are calculated in the framework of Quark Confinement Model. The account of the intermediate scalar mesons turns out to allow to explain ΔI = 1/2 rule. The account of intermediate scalar and pseudo-scalar states leads to experimental value of mass difference of K_L°–K_S° mesons. The obtained values for nonleptonic and electromagnetic decay widths as well as mass difference Δm_LS are in good agreement with experimental data.     

Attosecond manipulation of ionization and efficient broadband supercontinuum generation in stretched molecules

<正>We theoretically investigate the high-order harmonic generation from stretched molecules in a linearly polarized intense field.By adopting an infrared pulse combined with an ultraviolet(UV) attosecond pulse,the ionization process can be controlled effectively.In this excitation scheme,the harmonic spectrum beyond I_p+3.17U_P is significantly enhanced by two orders,where I_p and U_p=e~2E_0~2/(4m_eω~2) are the ionization and ponderomotive potential,then smooth broadband supercontinuum with the bandwidth of about 120 eV is obtained,which leads to an isolated sub-60- as attosecond pulse with a high signal-noise ratio.Moreover,the bandwidth of the supercontinuum is weakly dependent on the location and pulse duration of the UV pulse.