Cannabidiol and (-)Delta9-tetrahydrocannabinol are neuroprotective antioxidants

The neuroprotective actions of cannabidiol and other cannabinoids were examined in rat cortical neuron cultures exposed to toxic levels of the excitatory neurotransmitter glutamate. Glutamate toxicity was reduced by both cannabidiol, a nonpsychoactive constituent of marijuana, and the psychotropic cannabinoid (-)Delta9-tetrahydrocannabinol (THC). Cannabinoids protected equally well against neurotoxicity mediated by N-methyl-D-aspartate receptors, 2-amino-3-(4-butyl-3-hydroxyisoxazol-5-yl)propionic acid receptors, or kainate receptors. N-methyl-D-aspartate receptor-induced toxicity has been shown to be calcium dependent; this study demonstrates that 2-amino-3-(4-butyl-3-hydroxyisoxazol-5-yl)propionic acid/kainate receptor-type neurotoxicity is also calcium-dependent, partly mediated by voltage sensitive calcium channels. The neuroprotection observed with cannabidiol and THC was unaffected by cannabinoid receptor antagonist, indicating it to be cannabinoid receptor independent. Previous studies have shown that glutamate toxicity may be prevented by antioxidants. Cannabidiol, THC and several synthetic cannabinoids all were demonstrated to be antioxidants by cyclic voltametry. Cannabidiol and THC also were shown to prevent hydroperoxide-induced oxidative damage as well as or better than other antioxidants in a chemical (Fenton reaction) system and neuronal cultures. Cannabidiol was more protective against glutamate neurotoxicity than either ascorbate or alpha-tocopherol, indicating it to be a potent antioxidant. These data also suggest that the naturally occurring, nonpsychotropic cannabinoid, cannabidiol, may be a potentially useful therapeutic agent for the treatment of oxidative neurological disorders such as cerebral ischemia.     

Co-located collaborative visual analytics around a tabletop display

Co-located collaboration can be extremely valuable during complex visual analytics tasks. We present an exploratory study of a system designed to support collaborative visual analysis tasks on a digital tabletop display. Fifteen participant pairs employed Cambiera, a visual analytics system, to solve a problem involving 240 digital documents. Our analysis, supported by observations, system logs, questionnaires, and interview data, explores how pairs approached the problem around the table. We contribute a unique, rich understanding of how users worked together around the table and identify eight types of collaboration styles that can be used to identify how closely people work together while problem solving. We show how the closeness of teams’ collaboration and communication influenced how they performed on the task overall. We further discuss the role of the tabletop for visual analytics tasks and derive design implications for future co-located collaborative tabletop problem solving systems.     

The impedance of the alkaline zinc-mercuric oxide cell. I. Cell behaviour and interpretation of impedance spectra

The impedances of small (2400 mA h) alkaline Zn-HgO cells have been measured in the range 10 kHz-0.001 Hz at various states of charge from fully charged to fully discharged. The behaviour of the cell conforms to that expected for rate control by charge transfer at the zinc electrode and diffusion in solution. At low frequencies there is a relaxation in the diffusive circuit elements which ultimately results in a complete suppression of the capacitative component of the impedance at zero frequency. The low-frequency behaviour is analogous to convective diffusion and is due to the effective distance between the electrodes being small compared with the characteristic length (D/)^1/2. The magnitude of the charge transfer resistance is the best measure of the state of charge.Nomenclature a effective electrode separation - C _DL double-layer capacitance of cell - C _R capacitative component of cell impedance - C concentration difference - D percentage discharge in Equation 12 - D _i diffusion coefficient of speciesi - R ohmic resistance of cell - R _R resistive component of cell Faradaic impedance - Ui constant defined by Equation 10 - Z total cell impedance - Z _F cell Faradaic impedance - Z _F cell impedance modified for porosity effect - Z _x cell impedance of Faradaic component plus double layer - cell Warburg coefficient (slope ofR _R and 1/C _Rversus su}-1/2) - _C Warburg coefficient calculated fromC _r values - _i cell Warburg coefficient for speciesi - Warburg coefficient calculated fromR _R values - dihedral angle of tail of Sluyters plot (after coming-off high-frequency semicircle) - angular frequency     

The lead dioxide electrode

The recent literature dealing with the redox mechanism of the lead-acid cell positive electrode is reviewed. The basis electrochemistry of lead dioxide in its various polymorphic modifications and states of subdivision is considered in relation to the important aspects of electrode technology of which the major industrial application of the material is the conventional lead-acid cell. The proposed mechanism of the reduction (discharge) of lead dioxide in various acidic solutions are considered in relation to the present state of electrode kinetic theory. The reverse reaction by which lead dioxide is formed and the parasitic intrusion of the self discharge are dealt with as a precursor to the total cyclic process. It is concluded that in a number of respects the mechanisms proposed do not adequately represent the totality of the experimental observations. Such shortcomings are emphasized and extensions to present research are proposed.     

Potentiostatic step experiments on pasted Pb-Sb and Pb-Sn-Ca electrodes

A range of cyclic electrochemical experiments have been carried out on electrodes of porous PbO₂ supported on a number of Pb-Sb and Pb-Sn-Ca alloys using micro-computer controlled potentiostatic stepping techniques. The results show that, in certain cases, the differences in electrochemical behaviour of the PbO₂ can be interpreted as being due to the effect of the support alloy.     

The anodic behaviour of zinc in KOH solution. V: Galvanostatic polarization with an interruption

Galvanostatic polarization experiments, in which the current flow is interrupted and re-established, show that the process of passivation is controlled by the transport of mass in the solution phase.Part IV: M. J. Brook and N. A. Hampson,Electrochim Acta 15 (1970) 1749.     

The temperature dependence of the electrochemistry of the lithium-sulphur dioxide system

Value for the activation energy, U ^act, and the entropy change, S, for the reaction 2Li + S₂O ₄ ^2– Li₂S₂O₄+2e in acetonitrile have been found to be 72 kJ mol^–11 and — 0.3 kJ mol^–1 K^–1, respectively, by a combination of impedance techniques and the use of a temperature-controlled environment on commercially manufactured cells which acted as constant volume containers.     

The differential capacitance of solid tantalum in some aqueous solutions

The differential capacitance of tantalum has been measured in a number of aqueous electrolyte solutions. The metal is generally covered with an oxide layer in solutions of simple inorganic anions and the electrode capacitance is 5–10 F cm^–2. In solutions of oxalate anions the electrode capacitance is much higher and corresponds to that expected for a clean metal in contact with an aqueous solution.     

Autoxidation of fatty materials in emulsion. II. Factors affecting the histidine-catalyzed autoxidation of emulsified methyl linoleate

Several factors which affect autoxidation of methyl linoleate in emulsion have been examined. Data are presented which indicate: 1) In the presence of histidine, the ionic (anionic) emulsifiers examined promote autoxidation of emulsified methyl linoleate, but nonionic emulsifiers do not. 2) The concentration of an emulsifier affects the rate of oxygen absorption. 3) Inorganic salts (0.1 M or less) such as sodium chloride, sodium acetate and sodium sulfate affect oxygen absorption of emulsified methyl linoleate prepared with either ionic or nonionic emulsifiers. In histidine-catalyzed autoxidation there is a suppressing effect in the case of the ionic and a promotional effect in the case of the nonionic. In uncatalyzed autoxidation, these salts have a promotional effect in ionic emulsions and none in nonionic emulsions. 4) Sodium phosphate buffers completely suppress autoxidation due to histidine catalysis, but do not suppress the normal uncatalyzed autoxidation of emulsified methyl linoleate. 5) The pro-oxidative effects of histidine and histidine-metal ion complexes on emulsified unsaturated materials is not limited to polyolefins but also includes mono-olefinic compounds. Presented at the AOCS meeting in Toronto, October, 1962. E. Utiliz. Res. and Dev. Div., ARS, USDA.