Effects of goal-directed fluid therapy with different lactated Ringer's: hydroxyethyl starch ratios in hemorrhagic shock dogs.

The effects of goal-directed fluid therapy, with lactated Ringer's (LR) and 6% hydroxyethyl starch (HES) solution, on hemorrhagic shock dogs are unknown. We aimed to determine the optimal LR: HES ratio for the resuscitation of hemorrhagic shock dogs. Hemorrhagic shock was induced in 40 ventilated dogs by drawing an estimated 60% blood volume. The animals were randomly divided into five groups (N = 8) according to the LR: HES ratio of the resuscitation fluid (3:1, 2:1, 1:1, 1:2, and 1:3), and were then resuscitated for 24 h to reach the stroke volume variation (SVV) and hemoglobin (Hb) goals by fluid infusion and autologous blood perfusion. The extravascular lung water index (EVLWI), pH, partial pressure of oxygen (PaO2), base excess (BE), sodium, chloride, Hb and creatinine clearance (Clearcrea) were checked after 24 h (R24). The EVLWI of the 3:1 group at R24 were higher than that of the 1:3 group and the baseline value (P < 0.05), whereas the PaO2 was lower (P < 0.05). In contrast to the 3:1 group at R24 and baseline, plasma chloride and sodium in the 1:3 and 1:2 groups increased; however, pH, BE, and Clearcrea decreased (P < 0.05). No significant differences were found in the 1:1 and 2:1 groups at R24 compared with baseline (P > 0.05). Resuscitation with LR and HES at 2:1 and 1:1 ratios are superior in maintaining the acid-base, electrolyte, and lung water balances as well as renal function in hemorrhagic shock dogs than at ratios of 3:l, 1:2, and1:3.

A straightforward implementation of in situ solution electrochemical ¹³C NMR spectroscopy for studying reactions on commercial electrocatalysts: ethanol oxidation.

Identifying and quantifying electrocatalytic-reaction-generated solution species, be they reaction intermediates or products, are highly desirable in terms of understanding the associated reaction mechanisms. We report herein a straightforward implementation of in situ solution electrochemical (13)C NMR spectroscopy for the first time that enables in situ studies of reactions on commercial fuel-cell electrocatalysts (Pt and PtRu blacks). Using ethanol oxidation reaction (EOR) as a working example, we discovered that (1) the complete oxidation of ethanol to CO2 only took place dominantly at the very beginning of a potentiostatic chronoamperometric (CA) measurement and (2) the PtRu had a much higher activity in catalysing oxygen insertion reaction that leads to acetic acid.

In situ Raman spectroscopic measurement of near-surface proton concentration changes during electrochemical reactions.

We report a simple in situ Raman spectroscopic measurement of near-surface proton concentration changes at commercial Pt black nanoparticle surfaces using the well-known methanol oxidation, oxygen reduction, Pt oxidation and reduction reactions as the representative illustrating examples.

On the chemistry of activation of a commercial carbon-supported PtRu electrocatalyst for the methanol oxidation reaction.

Although potential cycling has been widely used to activate PtRu electrocatalysts for methanol oxidation, little is known about the molecular/atomic level chemistry involved and also what constitutes the optimal activation. This important question is addressed herein by in situ attenuated total reflection-surface enhanced IR reflection absorption spectroscopy using methanol-generated CO as a probe.

Resonant Raman scattering of the smallest single-walled carbon nanotubes.

We report optical properties of the smallest single-walled carbon nanotubes (SWNTs) with a diameter of only 3 A. These ultrasmall SWNTs are fabricated in the elliptical nanochannels of an AlPO-11 (AEL) single crystal. Polarized and resonant Raman scattering unambiguously revealed that these 0.3 nm SWNTs are of (2,2) armchair symmetry. Interestingly, the (2,2) armchair tube has two metastable ground states corresponding to two slightly different lattice constants in the axial direction: one state is metallic and the other is semiconducting.

Sex and aging in the city: Singapore.

A survey was carried out on 307 healthy men and 774 women, aged between 30 and 70 years to evaluate the determinants of sex life in the highly urbanized Singapore population. The results showed that significantly more women (28.8%) as compared to men (16.3%) were currently sexually inactive. The main reason for sexual inactivity for women was being divorced or widowed (37.9%) and for men, the loss of interest in sex (42.8%). Relationship problems and being stressed out in life were the next two most common reasons for both men and women. Coital frequency for men and women between the ages of 30 and 55 years averaged about five to six times monthly and was significantly reduced to about three times monthly in those above 55 years old. More men (25.7%) wanted to have more frequent sex than women (5.4%), but were unable to fulfill their desire and the primary reason was that they were too stressed out in life. Results from this study revealed that sex life is determined not only by physiological, but also cultural, social and lifestyle factors. In Singapore, life style factors accounted largely for sexual inactivity, and the inability to fulfill the desire for more frequent sex. The term 'lifestyle impotency' was coined to describe the group of men and women who were too stressed out in life to have sex. Therefore, there is a need to evolve a paradigm for the management of sexual dysfunctions by taking into account the underlying etiological factors which, as we have shown, may not be resolved by pharmaceutical interventions.

Diffusion on a nanoparticle surface as revealed by electrochemical NMR.

Surface diffusion of chemisorbed CO (from MeOH electrochemisorption) on pure and Ru-modified nanoscale Pt electrocatalyst surfaces has been investigated by solid-state electrochemical NMR (EC-NMR) in the presence of supporting electrolyte. Temperature-dependent nuclear spin-spin and spin-lattice relaxation measurements enable the diffusion activation energy, E, to be deduced. It is shown that the activation energy E correlates with the steady state current for MeOH electro-oxidation. A simple two-dimensional collision theory model is proposed to explain this intriguing observation, which may provide new mechanistic insights into the promotion of CO-tolerance in Pt/Ru fuel cell catalysts.

[Determination of active constituents in shi-wei (Folium Pyrrosiae) by high performance liquid chromatography].

A new analytical method for the simultaneous determination of three constituents, viz, mangiferin, isomangiferin and chlorogenic acid in Folium Pyrrosiae using high performance liquid chromatography was developed. A Zorbax-CN column (4.6 mm x 25 cm) was used; methanol--water--phosphoric acid (pH 2.5) (20:80:0.1) was used as the mobile phase. The method was rapid, sensitive, precise and showed good reproducibility. The three constituents in crude drugs were completely separated within 15 min. Recoveries of three constituents were 96.78-101.3%, with coefficients of variation 1.8-4.7%. Mangiferin and isomangiferin were separated for the first time. Pyrrosia plant materials were analyzed as follows: The powdered sample was refluxed with methanol for 4 hours, the extract was transferred into a 25 ml volumetric flask and diluted to 25 ml with methanol. A definite amount of this sample solution was injected for HPLC. The content of constituents in Folium pyrrosiae was calculated from the relevant peak height or peak area. The content of these three constituents in 7 species of Chinese Pyrrosia collected in 17 districts were determined. The results showed that these constituents varied greatly with the plant species and varied with the districts for the same species also, and should be evaluated accordingly.

[Determination of the active ingredients in Chinese drug wuweizi (Schisandra chinensis) by TLC-densitometry].

A method of TLC densitometry was developed to determine the active ingredients (Wuweizisu A, B, C; Wuweizichun A, B; Wuweizi ester and schisanhenol) in Schisandra kernels. The samples were extracted with hexane (3 X 5 ml) for 8, 4 and 4 h respectively. The hexane extract was evaporated to dryness and then dissolved in 1 ml of methanol. Standard solutions and sample solutions were spotted on a silica gel GF254 plate, and developed with toluene-ethyl acetate (9:1) for 18 cm (for Wuweizisu A, B, C) and with toluene-ethyl acetate (4:6) for 18 cm (for Wuweizichun A, B, Wuweizi ester and schisanhenol). On examining the chromatogram under UV light the ingredients appeared as dark spots. A Shimadzu TLC model 910 was used for scanning at lambda s 260 nm and lambda R 350 nm by reflection mode. Linear calibration curves were obtained for the 7 constituents in the range of 1-5 micrograms. The average recoveries of the 7 constituents were 92.4-101.6%; the variation coefficients were 1.62-5.28%. The spots were stable for more than 24 h. This method is sufficiently simple, rapid and accurate for routine analysis.

[Determination of the main alkaloids in wu tou (aconite) by TLC-densitometry].

A method of TLC densitometry was established in order to determine the main alkaloids: mesaconitine, aconitine and hypaconitine in Aconite root. The powdered sample was alkalinized by ammonia and macerated with ether for 24 h. The mixture was then centrifuged, the residue was washed three times each with 2 ml of fresh ether, the combined ether extract was evaporated to dryness and then dissolved in 1 ml of dichloromethane. Standard solution and sample solution were spotted on a sillca gel GF254 plate, and developed with cyclohexane-ethyl acetate-diethylamine (8:1:1), the chromatogram was observed under UV light as dark spots. A Shimazu TLC model 910 was used for scanning at lambda s 236 nm and lambda R 350 nm by reflection mode. Linear calibration curves were obtained for the 3 constituents in the range of 2-6 micrograms. The average recoveries of masaconitine, aconitine and hypaconitine were 97.3, 96.4, 99.1% and the variation coefficients were 1.81, 1.72, 1.18%, respectively. The spots were stable for more than 24 h. Samples from various sources were analyzed.

[Determination of Lignans in the fruits of Schisandra chinensis (Trucz.) Baill. and S. Sphenanthern Rehd. et Wils. using HPLC and their chromatograms].

The lignans contained in the fruits of Schisandra chinensis and S. sphenanthern were determined by HPLC. Their chromatograms are different. 7 samples of S. chinensis from 6 habitats contain the same lignans, but in different quantity, while 16 samples of S. sphensnthern contain lignans different both in quality and quantity.

Application of ion-pair high performance liquid chromatography for analysis of hyoscyamine and scopolamine in solanaceous crude drugs.

A new ion-pair high-performance liquid chromatographic method for the analysis of hyoscyamine and scopolamine in various kinds of crude drugs derived from solanaceous plants was evaluated using sodium dodecyl sulfate as a counter ion. A reversed-phase chromatographic system consisting of a chemically bonded ODS silica gel column with phosphate buffer (pH 2.5)-acetonitrile (65:35) containing 17.5 mM sodium dodecyl sulfate as the mobile phase was used. Hyoscyamine and scopolamine in crude drugs derived from Scopolia, Atropa, Hyoscyamus and Datura species were separated from other compounds in the crude drugs and determined within 20 min after direct injection of the solution extracted with the mobile phase. The results for various kinds of samples are presented.

[Determination of geniposide in fructus Gardeniae and its pharmaceutical preparations by HPLC].

A method for the determination of geniposide in Fructus Gardeniae was established by HPLC. HPLC conditions: column: TSK GEL LS-410, mobile phase: 0.05 mol/L Na2 HPO4-MeOH (80:20) (pH = 6.86). Quantitative determination was made using peak area. Samples of various parts of the plant and of different habitats together with their pharmaceutical preparations were analyzed.