Link between KAM tori and nearby cycles

In the discussion of GUTS in the early universe it is assumed that there exists a locally inertial space-time region large enough to contain a sufficient number of particles justifying the use of flat space statistical mechanics. We show that this assumption is false.     

Olivine-type nanoparticle for hybrid supercapacitors

LiCoPO₄ nanoparticles were precipitated from polyethylene glycol solution of lithium acetate, cobalt acetate, and ammonium dihydrogen phosphate by refluxing at 250 °C for 35 h. The resultant powder samples were heated at 800 °C for different time periods of 2 and 4 h to study the effect of annealing time on the growth of samples. The X-ray diffraction pattern of the obtained samples exhibited olivine phase. The scanning electron microscopic images of dried powder sample and samples heated at 800 °C for 2 and 4 h showed a homogenous orthorhombic morphology with a particle size of few nanometers range. For the first time, orthorhombic olivine was introduced as positive electrode for a hybrid electrochemical supercapacitor cell with carbon nanofoam as negative electrode in 1 M LiClO₄ in ethylene carbonate and propylene carbonate (1:1 in volume) solution. A sloping voltage profile of 2 to 0 V is observed for all the three hybrid cells. From the impedance results, we inferred that LiCoPO₄ nanoparticles synthesized by polyol process offers less resistance than lithium titanium oxide. According to the results of electrochemical testing for the first time, maximum power density of 192 W/kg at 11 Wh/kg energy density was obtained for LiCoPO₄ nanoparticles annealed at 800 °C for 2 h. The dried sample and the sample heated at 800 °C for 2 and 4 h exhibited high capacitances of 5, 19, and 4 F/g, respectively, with an excellent rate capability over 1,000 cycles.     

Hypolipidemic potential of flowers of Nerium oleander in high fat diet-fed Sprague Dawley rats

Nerium oleander Linn. (NO), an evergreen shrub, is used in folklore medicine as a cardiotonic and exhibits a wide spectrum of bioactivities. Herein, the hypolipidemic potential of the ethanolic extract of flowers of Nerium oleander (ENO) in a minimal dose was assessed. A high fat diet (HFD) resulted in a significant increase in cardiac lipids and lipoproteins and an increase in body weight gain. Simultaneous treatment with ENO significantly lowered the increase in body weight gain, lipid and lipoprotein levels, with a concomitant increase in HDL in the plasma and heart when compared to HFD-fed rats. Likewise, the activities of lipolytic enzymes were also upheld by the ENO treatment in the heart compared to HFD-fed rats. The above findings highlight the possible mechanism of N. oleander as a hypolipidemic agent in its use in folklore medicine as a cardiotonic.     

Cytotoxic copper(II) complex of tripyridoquinoxaline with DNA hydrolase activity

A monomeric copper(II) complex, [Cu(tpq)₂(H₂O)₂](ClO₄)₂, (tpq = tripyridoquinoxaline), has been synthesized and characterized spectroscopically. This complex has been found to bind DNA intercalatively and the DNA binding constant, K_b, for this complex has been determined from absorption measurements and was found to be (5.7 ± 0.3) × 10³ M⁻¹. This complex successfully promotes hydrolytic cleavage of plasmid DNA, producing single and double DNA strand breaks in the absence of any added cofactor. The amount of conversion of the supercoiled form of plasmid to the nicked circular form depends on the concentration of the copper complex as well as the duration of the incubation of the complex with DNA. The rate of conversion of SC to NC has been determined to be 2.65 × 10⁻⁴ s⁻¹ at pH 7.2 in the presence of 80 μM of the complex. This complex has also been shown to be cytotoxic towards A549 lung adenocarcinoma cells. This complex has been shown to bring about apoptosis of the cancerous A549 cell line.     

Thermal and Optical Characterization of Multiple Hydrogen Bonded Liquid Crystals and Its Application in Display Devices

Russian Journal of Physical Chemistry A - Novel homologous series of phloroglucinol (PG) and 4-n-alkyloxybenzoic acid (nOBA, n = 4 to 12) hydrogen bonded liquid crystal (HBLC) complex have been...     

Prussian blue solid-state films and membranes as potassium ion-selective electrodes

The use of thin films of Prussian blue and heterogeneous Prussian blue membranes as potassium ion-selective electrodes was investigated. All of the heavier group I cations and NH⁺₄ interfere strongly but there is relatively good selectivity towards Na⁺ with a selectivity coefficient of ca. 5 × 10^?3. The thin-film measurements, based on Prussian blue deposited on platinum, involve conditioning the electrode to a fixed potential according to the method used by Engel and Grabner for copper hexacyanoferrate(III) films. The membrane electrodes were based on mixing Prussian blue with polymeric supporting films such as polystyrene and epoxy. A particularly simple practical configuration involves Prussian blue membranes deposited directly on copper conductors where one membrane serves as a reference electrode. A reversible cell, without liquid junction, is formed with Prussian blue and Ag/AgCl electrodes and this serves as a means for determining an accurate value for the standard reduction potential of Prussian blue, which is found to be 0.238 V vs. Ag/AgCl at 25 °C.     

Multicomponent solid forms of the uric acid reabsorption inhibitor lesinurad and cocrystal polymorphs with urea: DFT simulation and solubility study

Lesinurad (systematic name: 2‐{[5‐bromo‐4‐(4‐cyclopropylnaphthalen‐1‐yl)‐4H‐1,2,4‐triazol‐3‐yl]sulfanyl}acetic acid, C₁₇H₁₄BrN₃O₂S) is a selective uric acid reabsorption inhibitor related to gout, which exhibits poor aqueous solubility. High‐throughput solid‐form screening was performed to screen for new solid forms with improved pharmaceutically relevant properties. During polymorph screening, we obtained two solvates with methanol (CH₃OH) and ethanol (C₂H₅OH). Binary systems with caffeine (systematic name: 3,7‐dihydro‐1,3,7‐trimethyl‐1H‐purine‐2,6‐dione, C₈H₁₀N₄O₂) and nicotinamide (C₆H₆N₂O), polymorphs with urea (CH₄N₂O) and eutectics with similar drugs, like allopurinol and febuxostat, were prepared using the crystal engineering approach. All these novel solid forms were confirmed by XRD, DSC and FT–IR. The crystal structures were solved by single‐crystal and powder X‐ray diffraction. The crystal structures indicate that the lesinurad molecule is highly flexible and the triazole moiety, along with the rotatable thioacetic acid (side chain) and cyclopropane ring, is almost perpendicular to the planar naphthalene moiety. The carboxylic acid–triazole heterosynthon in the drug is interrupted by the presence of methanol and ethanol molecules in their crystal structures and forms intermolecular macrocyclic rings. The caffeine cocrystal maintains the consistency of the acid–triazole heterosynthons as in the drug and, in addition, they are bound by several auxiliary interactions. In the binary system of nicotinamide and urea, the acid–triazole heterosynthon is replaced by an acid–amide synthon. Among the urea cocrystal polymorphs, Form I (P, 1:1) consists of an acid–amide (urea) heterodimer, whereas in Form II (P2₁/c, 2:2), both acid–amide heterosynthons and urea–urea dimers co‐exist. Density functional theory (DFT) calculations further support the experimentally observed synthon hierarchies in the cocrystals. Aqueous solubility experiments of lesinurad and its binary solids in pH 5 acetate buffer medium indicate the apparent solubility order lesinurad–urea Form I (43‐fold) > lesinurad–caffeine (20‐fold) > lesinurad–allopurinol (12‐fold) ? lesinurad–nicotinamide (11‐fold) > lesinurad, and this order is correlated with the crystal structures.     

Resonance Raman and infrared spectroscopic studies of high-output forms of human soluble guanylyl cyclase

The allosteric regulator BAY-41-2272 converts the CO adduct of soluble guanylyl cyclase (CO-sGC) enzyme from a low- to high-output form, with respect to production of cGMP. Resonance Raman (RR) and Fourier Transform Infrared (FTIR) spectroscopic techniques are used to show that the CO-sGC exists as major and minor conformers, both having nu(Fe-CO) and nu(C-O) modes characteristic of 6-coordinate species. It is further shown that addition of BAY-41-2272 to the CO adduct induces the transition of some fraction of the initial CO-heme adducts into two new CO-heme complexes, the fractional conversion being dependent on the temperature. One new complex displays vibrational modes characteristic of pentacoordinated CO-adduct, and its formation is not affected by temperature. The second complex, although slightly different from the original CO-adducts, is hexacoordinated, and its formation is facilitated by temperature. The production of substantial amounts of the 5-coordinate CO adduct upon addition of BAY-41-2272, reveals the fact that several out-of-plane heme deformation modes are simultaneously activated, an observation similar to that realized upon NO activation. While the precise nature of these modes will require elucidation by isotopic labeling experiments, by analogy with earlier studies of other heme proteins, several bands associated with modes attributable to peripheral substituent deformations and methine carbon movements are implicated. The documented formation of two new forms upon addition of Bay-41-2272 (a 5-coordinate and a new 6-coordinate form) is discussed with respect to the implications for enzyme activation.     

Synthesis and electrochemical studies of LiMn1−xCuXO4 cathode material

LiMn_1.8Cu_0.2O₄ was investigated in order to improve the electrochemical properties of LiMn₂O₄. We report the synthesis and characterization of materials prepared by solid-state reaction. The structural properties evaluated by the X-ray diffraction and vibrational spectroscopy show that a single phase was formed. Conductivity of LiMn_1.8Cu_0.2O₄ cathode is found to be 8×10⁻⁶ S/cm at 25 °C. The cyclic voltammetry data shows the reversibility of the electrode material. Paper presented at the 7th Euroconference on Ionics, Calcatoggio, Corsica, France, Oct. 1–7, 2000.