Abstract  Volcanoes are very strong sources of sulphur, acids and other gases, as well as particles, that are of atmospheric relevance. Some gases only behave as passive tracers, others affect the formation, growth or chemical characteristics of aerosol particles and many lead to adverse effects on vegetation and human health when deposited in the vicinity of volcanoes. In this article the main effects of volcanic emissions on atmospheric chemistry are discussed, with a focus on sulphur and halogen compounds, and to a smaller extent on climate. We primarily focus on quiescent degassing but the main effects of explosive eruptions on the troposphere and stratosphere are covered as well. The key distinction between chemistry in magmatic and hydrothermal settings and the atmosphere is that the atmosphere is oxidising whereas the chemistry is typically reducing in the former cases due to very low oxygen concentrations. Rapid catalytic cycles involving radicals are a further characteristic of atmospheric chemistry. Most reaction cycles involve the photolysis of molecules as a key part of the reaction chains. Recent measurements of halogen radicals in volcanic plumes showed that volcanic plumes are chemically very active. We explain the formation mechanism of halogen oxides in plumes as well as their relevance for the atmosphere. (C) 2008 Elsevier B.V. All rights reserved.

Abstract  P>Background: Epidural and other regional blocks are performed in children under general anesthesia; the response to a 'test dose' may be altered during administration of general anesthetics. Limited data is available describing changes in electrocardiogram, blood pressure and heart rate (HR) following unintentional intravascular injection of a lidocaine-epinephrine-containing test dose, under sevoflurane anesthesia in children. Methods: Sixty-eight children undergoing elective surgeries under sevoflurane anesthesia were administered 0.1 ml center dot kg-1 of 1% lidocaine with epinephrine 0.5 mu g center dot kg-1 or normal saline intravenously, to simulate an accidental intravascular test dose. T-wave changes in lead II on the anesthesia monitor and on a printed ECG were noted over the initial 1 min as well as changes in HR and systolic blood pressure (SBP) over an initial 3 min period. Results: Following injection of lidocaine-epinephrine, a significant increase in T-wave amplitude in lead II was noted in 91% of children on the ECG monitor and in 94% of children on the ECG printout of the same lead. In 64% of children, an increase in HR of >= 10 b center dot min-1 and in 76% of children an increase in SBP of >= 15 mmHg was noted. Conclusion: An increase in T-wave amplitude can easily be detected by carefully observing the ECG monitor or an ECG printout within a minute following the accidental i.v. administration of 0.1 ml center dot kg-1 of 1% lidocaine-epinephrine (0.5 mu g center dot kg-1) regional anesthetic test dose in children under sevoflurane anesthesia.

Abstract  Abstract: α-PW12O40 ^{3−} (PW12) supported on the surface of silica gel derivatized by 3-aminopropyl(triethoxy)silane (devoted briefly as SiNH3PW12) was synthesized and used as bulk modifier to fabricate a renewable three-dimensional chemically modified electrode. The electrochemical behavior of the modified electrode was characterized by cyclic voltammetry. There is an ionic bonding character between PW12 and the surface amino groups of modified silica, which greatly improves the stability of SiNH3PW12-modified carbon paste electrode due to insolubility of silica gel in water. The SiNH3PW12 bulk-modified carbon paste electrode not only maintains the electrochemical activity of PW12, but also exhibits remarkable advantages of renewability, as well as simple preparation and inexpensive material. The modified electrode offers an excellent and stable electrocatalytic response for the reduction of IO3 ^{−} and hydrogen peroxide. The SiNH3PW12-CPE is successfully applied as an electrochemical detector to monitor IO3 ^{−} in flow injection analysis (FIA). The catalytic peak current was found to be linear with the IO3 ^{−} concentration in the range 5×10^{−6} to 1×10^{−3} molL^{−1}. The detection limit of the proposed method was found to be 3.1×10^{−6} molL^{−1} for IO3 ^{−} determination. [Copyright 2008 Elsevier] Copyright of Talanta is the property of Elsevier Science Publishers B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts)

Abstract  During the steady-state period of activity of La Soufriere Volcano in 1979, the mass emissions of sulfur dioxide into the troposphere amounted to a mean value of 339 +/- 126 metric tons per day. This value is similar to the sulfur dioxide emissions of other Central American volcanoes but less than those measured at Mount Etna, an exceptionally strong volcanic source of sulfur dioxide.

Abstract  Background and objective Anaesthetic preconditioning (APC) exerts cardioprotective effects by reducing infarct size and improving recovery of contractile function after ischaemia-reperfusion. The interval between brief exposure to volatile anaesthetic and sustained ischaemia, the acute memory phase, is dependent on intracellular signalling mediating this cardioprotection. Intramyocyte translocation of protein kinase C (PKC) is known to be a key mediator in APC. We examined the relationship between the time frame of the acute memory phase of sevoflurane preconditioning and intramyocyte translocation of PKC-alpha, delta and epsilon to the particulate fraction.

Methods Isolated perfused guinea pig hearts were subjected to 30min ischaemia and 120min reperfusion. APC was elicited with one minimum alveolar concentration sevoflurane for 10 min. Washout times of 10, 30, 60 and 90 min were studied. Contractile recovery was assessed by monitoring left ventricular developed pressures. Infarct size was determined by triphenyltetrazolium chloride staining. Translocation of PKC was examined by western blot analysis.

Results After ischaemia-reperfusion, left ventricular developed pressure recovered to a greater degree with APC compared with control for washout times of 10 and 30 min, but not 60 and 90 min. Similarly, infarct size was reduced for washout times of 10 and 30 min, but not 60 and 90 min. Sustained translocation of PKC-alpha and epsilon, but not delta, was associated with the time frame of the acute memory phase.

Conclusion The acute memory phase of sevoflurane preconditioning is limited to less than 60 min. Sustained translocation of PKC-alpha and epsilon, but not delta, correlates with this acute memory phase of sevoflurane preconditioning. Eur J Anaesthesiol 26:582-588 (C) 2009 European Society of Anaesthesiology.

Abstract  Volcanoes can emit fine-sized ash particles (1-10 mu m radii) into the atmosphere and if they reach the upper troposphere or lower stratosphere, these particles can have deleterious effects on the atmosphere and climate. If they remain within the lowest few kilometers of the atmosphere, the particles can lead to health effects in humans and animals and also affect vegetation. It is therefore of some interest to be able to measure the particle size distribution, mass and other optical properties of fine ash once suspended in the atmosphere. A new imaging camera working in the infrared region between 7-14 mu m has been developed to detect and quantify volcanic ash. The camera uses passive infrared radiation measured in up to five spectral channels to discriminate ash from other atmospheric absorbers (e.g. water molecules) and a microphysical ash model is used to invert the measurements into three retrievable quantities: the particle size distribution, the infrared optical depth and the total mass of fine particles. In this study we describe the salient characteristics of the thermal infrared imaging camera and present the first retrievals from field studies at an erupting volcano. An automated ash alarm algorithm has been devised and tested and a quantitative ash retrieval scheme developed to infer particle sizes, infrared optical depths and mass in a developing ash column. The results suggest that the camera is a useful quantitative tool for monitoring volcanic particulates in the size range 1-10 mu m and because it can operate during the night, it may be a very useful complement to other instruments (e.g. ultra-violet spectrometers) that only operate during daylight. (C) 2009 Elsevier B.V. All rights reserved.

Abstract  The gasotransmitter hydrogen sulfide is known to regulate multiple cellular functions during normal and pathophysiological states. However, a paucity of concise information exists regarding quantitative amounts of hydrogen sulfide involved in physiological and pathological responses. This is primarily due to disagreement among various methods employed to measure free hydrogen sulfide. In this article, we describe a very sensitive method of measuring the presence of H₂S in plasma down to nanomolar levels, using monobromobimane (MBB). The current standard assay using methylene blue provides erroneous results that do not actually measure H₂S. The method presented herein involves derivatization of sulfide with excess MBB in 100 mM Tris-HCl buffer (pH 9.5, 0.1 mM DTPA) for 30 min in 1% oxygen at room temperature. The fluorescent product sulfide-dibimane (SDB) is analyzed by RP-HPLC using an eclipse XDB-C18 (4.6 × 250 mm) column with gradient elution by 0.1% (v/v) trifluoroacetic acid in acetonitrile. The limit of detection for sulfide-dibimane is 2 nM and the SDB product is very stable over time, allowing batch storage and analysis. In summary, our MBB method is suitable for sensitive quantitative measurement of free hydrogen sulfide in multiple biological samples such as plasma, tissue and cell culture lysates, or media.

Abstract  Various 2-(6-substituted 3(Z)-hexen-1,5-diynyl)anilines 1a-g were treated with potassium tert-butoxide or potassium 3-ethylpentanoxide in NMP at 60 degrees C for 2 h to give the corresponding 5-substituted carbazoles 2a-g in 36-65% yields together with indoles 9a-g in 21-40% yields, respectively. Exposing the trifluoroacetamide analogues 10h-k under the same reaction conditions gave the carbazoles 2b-e in 37-57% yields and indoles 9b-e in 15-27% yields. Subsequent cyclizations of acetamide analogues 10a-g gave carbazoles 2a-g in 53-86% yields

Abstract  In this review, we present the various microbial enzymatic systems involved in chlorocarbon biodegradation and evaluate their potential use as biocatalysts for the destruction of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons. Based on our present knowledge of the microbial metabolism of halogenated organic compounds, both anaerobic and aerobic processes could theoretically be used for the destruction of CFCs. The anaerobic processes result in the reductive dehalogenation of halogenated compounds. We describe the biological systems that were found to be involved in the reductive dehalogenation of halogenated hydrocarbons, present a number of hypotheses that have been proposed to explain this phenomenon, and discuss the potential use of these systems for the destruction of CFCs. The aerobic processes are based on the capacity of several large-spectrum activity mono- and dioxygenases that catalyze the initial oxidative step of aliphatic as well as aromatic compounds. In this case, the halogenated alkenes are converted to alkene epoxides that are quite unstable and break down to products that are readily metabolizable by other microorganisms. We discuss the potential use of this type of reaction for the destruction of CFCs and present approaches using genetically engineered microorganisms to more efficiently degrade these compounds.

Abstract  Haloacetic acid (HAA) concentrations were measured in air samples from a semi-rural and a highly urbanized site in southern Ontario throughout 2000 to investigate their sources and gas-particle partitioning behavior. Denuders were efficient for collection of gaseous HAAs, and the particle phase was collected on a downstream quartz filter with negligible breakthrough. Total HAA concentrations (i.e., gas + particles) ranged between <0.025 and 19 ng m(-3) for individual HAAs at both sites. The dominant airborne HAA was monochloroacetic acid (MCA), followed in decreasing order by dichloroacetic acid (DCA), trifluoroacetic acid (TFA), and trichloroacetic acid (TCA). Difluoroacetic acid (DFA), monofluoroacetic acid (MFA), and chlorodifluoroacetic acid (CDFA) were also frequently detected at lower concentrations. Between sites, TFA, DFA, MFA, and TCA concentrations were significantly higher in Toronto, while CDFA concentrations were higher in Guelph. HAAs were primarily in the gas phase all year; however, during colder months, particle-phase HAA concentrations increased relative to the gas phase. Trichloroacetic acid had the highest particle fraction (phi) for all detected HAAs, with a mean phi of 0.51 and 0.56 for Guelph and Toronto, respectively, and both vapor pressure and acid strength appeared to influence gas-particle partitioning. Temporal trends at both sites were partially explained by temperature, short-wave radiation, and particle mass (PM10), leading to indications of the respective sources. A simple deposition model indicated that dry deposition of TFA and TCA should not be neglected in temperate mid-latitude environments and that precipitation concentrations can be successfully predicted by the Henry's law constant.

Abstract  The specific features of balanced anesthesia utilizing sevoflurane (versus isoflurane) during thoracic operations under artificial one-lung ventilation (AOL ) have been studied in patients at high operative and anesthetic risks. Unlike isoflurane, sevflurane fails to cause vasodilatation in both the greater and lesser circulation (including in the gas-exchange part ofpulmonary circulation). The difference of the anesthetics in their vasodilating capacity in the vessels of pulmonary and systemic circulation determines various mechanisms of pathophysiological and adaptive circulatory changes in pulmonary collapse and under AOL V Under sevoflurane anesthesia, compensatory blood flow limitation along the collaborated lung due to permanently vasohypertension in gas-exchange microcirculation is accompanied by a systemic circulatory response that is aimed at reducing right ventricular load. Termination of hypoxic pulmonary vasoconstriction in the collaborated lung occurs not early than 80-125 min of AOLV, fails to lead to recovery of impaired gas exchange due to vasohypertension and high shunt in the ventilated lung, and is attended by right ventricular overload. The latter differentiates sevoflurane anesthesia from isoflurane one wherein completion of pulmonary hypoxic vasoconstriction upon 80-125-min exposure to AOL V results in the recovery of gas exchange to the baseline levels. The pattern of reperfusion changes in ventilation emergence in the operated lung under anesthesia using both sevoflurane and isoflurane is of no significant pathological tinge and it is followed by no pulmonary and systemic metabolic disturbances. Isoflurane should be recognized to be preferable component at the stage of anesthesia maintenance in patients with cardiopulmonary diseases during thoracic operations under prolonged AOL V (more than 2 hours).

Abstract  The study evaluated the effect of ozone application on the composite-to-composite bond. Three hundred and twenty cylindrical composite specimens were divided into two groups: group 1 was subjected to a 60 s ozone application, whereas group 2 remained untreated. Four subgroups were obtained from each group according to the intermediate repair agent: an adhesive, a silane, silane/adhesive combination, or flowable composite. Repair composite cylinders were built-up. The composite repair strength was tested after 24 h and after thermocycling with a shear test. Additionally, 4 mm x 4 mm x 2 mm composite specimens were prepared and stored 24 h in deionized water. Half of the specimens were subjected to ozone application and the other served as control. The elastic modulus (E) and the Vicker's hardness (VH) of the composite surfaces were tested immediately and after thermocycling. Significant differences among the experimental groups were detected (p < 0.001). The composite repair strength was affected by the pretreatment and by the intermediate agent, whereas, the thermocycling was not significant. The partial eta-squared statistics showed that the intermediate agent was the main factor affecting the composite repair strength, whereas the pretreatment played a minor role. No differences were observed between ozone and control groups when the same intermediate agent and the same aging conditions were applied. Repairing with flowable composite tended to achieve higher bond strengths (20.7 and 26.5 MPa in ozone and control groups, respectively, after 24 h). The use of silane coupling agent showed the lowest composite repair strengths. Ozone did not affect E and VH (p > 0.05) and the thermocycling affected only E (p < 0.05). In conclusion, the application of ozone does not impair the composite-to-composite bond.

Abstract  OBJECTIVE: Study on the of content variety of flavonoids in the course of processing Cortex Moutan,and discuss the preparation mechanism of Cortex Moutan Carbonisatum (CMC). METHOD: HPLC method was developed for the determination of flavonoids in various extent of CMC, the sample was extracted by ultrasound 30 min twice along with ethanol 50 mL. Chromatographic conditions were as follows: wavelength 360 nm, gradient eluant of methanol--0.5% per hundred trifluoroacetic acid. RESULT: The content of the three flavonoids cuts down along with the processing time and the rising temperature. CONCLUSION: The impact of various extent of processing on flavonoids content of the CMC is very great. The overall trend is that high temperature and long time lead to the lower of the content of flavonoids. This provides a basis data for the further study on the hemostatic mechanism and quality control of CMC.

Abstract  Five new, unsymmetrical 1,4-distyryl-2,5-bisphenylethynylbenzenes (cruciforms, XF) have been prepared by a sequential Horner reaction of the bisphosphonate of 2,5-diiodo-1,4-xylene with two different aromatic aldehydes. The obtained diiodide was coupled to phenylacetylene under Sonogashira conditions with (Ph3P)2PdCl2 as catalyst. The resulting XFs carry dibutylamino, pyridyl, cyano, and diphenylamino residues on their styryl arms to give rise to donor−, acceptor−, and donor−acceptor-substituted XFs. The optical properties of these XFs were investigated. Titration studies using trifluoroacetic acid tracked changes in the electronic structure of the XFs upon protonation. Donor XFs display a blue shift in absorption and emission upon protonation, while the pyridyl-substituted XF displays red shift in absorption and emission upon protonation. In the case of the donor−acceptor XF carrying a pyridyl and an aminostyryl arm, the first protonation occurs either on the pyridine or on the dibutylamino arm; a red shift is seen in absorption (for the former) and a blue shift is observed in emission (for the latter). The titration studies indicate that the protonated XFs do not display kinetic photoacidity when operating either in dichloromethane or acetonitrile solutions. The trends observed for protonation were mirrored when the XFs bind to metal cations. While the binding constants of the metal cations to the XFs were lower than for that for protons, as in some cases full metalation of the XF could not be obtained, the results were qualitatively the same. We did not find dynamic excited-state decomplexation events in the XFs that we have investigated. The XFs, stilbene derivatives, are different from other reported, similarly structured fluorophores as they show significant ratiometric changes in emission upon metal complexation; thus, distyrylbenzene-derived fluorophores may be, in the end, viable choices as platforms for metal ion detection.

Abstract  OBJECTIVES: In July 1995 the Soufriere Hills volcano on the island of Montserrat began to erupt. Preliminary reports showed that the ash contained a substantial respirable component and a large percentage of the toxic silica polymorph, cristobalite. In this study the cytotoxicity of three respirable Montserrat volcanic ash (MVA) samples was investigated: M1 from a single explosive event, M2 accumulated ash predominantly derived from pyroclastic flows, and M3 from a single pyroclastic flow. These were compared with the relatively inert dust TiO(2) and the known toxic quartz dust, DQ12. METHODS: Surface area of the particles was measured with the Brunauer, Emmet, and Teller (BET) adsorption method and cristobalite content of MVA was determined by x ray diffraction (XRD). After exposure to particles, the metabolic competence of the epithelial cell line A549 was assessed to determine cytotoxic effects. The ability of the particles to induce sheep blood erythrocyte haemolysis was used to assess surface reactivity. RESULTS: Treatment with either MVA, quartz, or titanium dioxide decreased A549 epithelial cell metabolic competence as measured by ability to reduce 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). On addition of mannitol, the cytotoxic effect was significantly less with M1, quartz, and TiO(2). All MVA samples induced a dose dependent increase in haemolysis, which, although less than the haemolysis induced by quartz, was significantly greater than that induced by TiO(2). Addition of mannitol and superoxide dismutase (SOD) significantly reduced the haemolytic activity only of M1, but not M2 or M3, the samples derived from predominantly pyroclastic flow events. CONCLUSIONS: Neither the cristobalite content nor the surface area of the MVA samples correlated with observed in vitro reactivity. A role for reactive oxygen species could only be shown in the cytotoxicity of M1, which was the only sample derived from a purely explosive event. These results suggest that in general the bioreactivity of MVA samples in vitro is low compared with pure quartz, but that the bioreactivity and mechanisms of biological interaction may vary according to the ash source.

Abstract  Two short-term in vitro tests for mutagenicity (Salmonella reverse mutation and BHK21 cell transformation) were conducted on a series of fluorocarbons. Some of these materials (FC22, FC31, FC142b, FC143, and FC143a) were found to be positive in one or both of the tests and could therefore be considered as being potentially carcinogenic to animals. Such activity was not anticipated for what were previously considered inert materials and in consequence several examples of these fluorocarbons, which represented different combinations of short-term test results, were tested for carcinogenicity in limited in vivo bioassays. In these studies, rats were dosed for 1 year by gavage 5 days a week with either FC22, FC31, FC133a, FC134a, or FC143a dissolved in a corn-oil at a single dosage of 300 mg/kg body weight. The animals were then observed until week 125 with detailed necropsy at termination. The study revealed that FC31 was a potent carcinogen (to the rat stomach), a result which reflected the short-term test predictions, but FC133a, which gave a negative response in both the in vitro assays, induced a high incidence of reproductive tract tumors. The weak bacterial mutagens FC22 and FC143a did not induce tumors in this study, and the nonmutagenic FC134a was without overt carcinogenic activity. It is concluded that, while recognizing the limitations of the in vivo component of this study, the short-term tests were only partially successful in identifying potential carcinogens for this series of chemicals. Fluorocarbon 31 was a potent carcinogen which was first identified by bacterial mutation and cell transformation, whereas the equally potent carcinogen FC133a was not so identified. The lack of genotoxic activity with this particular compound leads us to believe that the carcinogenic activity may be due to mechanisms other than those which involve direct DNA interactions.

Abstract  Conclusions: Human kidney microsomes metabolize methoxyflurane, and to a much lesser extent sevoflurane, to fluoride ion. P450s 2E1 and/or 2A6 and P450 3A are Implicated in the defluorinatlon. If intrarenally generated fluoride or other metabolites are nephrotoxic, then renal metabolism may contribute to methoxyflurane nephrotoxicity. The relative paucity of renal sevoflurane defluorinatlon may explain the absence of clinical sevoflurane nephrotoxicity to date, despite plasma fluoride concentrations that may exceed 50 "mu"m.

Abstract  Five men were exposed to toluene diisocyanate (TDI) atmospheres for 7.5 h. The TDI atmospheres were generated by a gas-phase permeation method, and the exposures were performed in an 8-m3 stainless-steel test chamber. The mean air concentration of TDI was ca. 40 μg/m3, which corresponds to the threshold limit value (TLV) of Sweden. The inhaled doses of 2,4- and 2,6-TDI were ca. 120 μg. TDI in the test chamber air was determined by an HPLC method using the 9-(N-methyl-aminomethyl)-anthracene reagent and by a continuous-monitoring filter-tape instrument. After hydrolysis of plasma and urine, the related amines, 2,4- and 2,6-toluenediamine 2,4-, and 2,6-TDA), were determined as pentafluoropropionic anhydride (PFPA) derivatives by capillary gas-chromatography using selected ion monitoring (SIM) in the electron-impact mode. The urinary elimination of the TDAs showed a possible biphasic pattern, with rapid first phases for 2,4-TDA (mean t 1/2 for the concentration in urine, 1.9 h) and for 2,6-TDA (mean t 1/2 for the concentration in urine, 1.6 h). The cumulative amount of 2,4-TDA excreted in urine within 28 h ranged from 8% to 14% of the estimated dose of 2,4-TDI, and the cumulative amount of 2,6-TDA in urine ranged from 14% to 18% of the 2,6-TDI dose. The average urinary level of 2,4-TDA was 5 μg/l in the 6 to 8-h sample (range 2.8–9.6 μg/l), and the corresponding value for 2,6-TDA was 8.6 μg/l (range, 5.6–16.6 μg/l). Biological monitoring of exposure to 2,4- and 2,6-TDI by analysis of 2,4- and 2,6-TDA in urine is feasible.

Abstract  The metabolism and pharmacokinetic characteristics of 1,1-dichloro-2,2,2-trifluoroethane (306832) (HCFC-123), 2-chloro-1,1,1,2-tetrafluoroethane (2837890) (HCFC-124), 1-chloro-1,1-difluoroethane (75683) (HCFC-142b), and perfluorohexane (355420) (PFH) were studied in rats. The study was part of a program to investigate possible health hazards presented by candidate Halon replacements for use as a fire extinguishant. Male Fischer-344-rats and Sprague-Dawley-rats were exposed nose only to 10,000 parts per million (ppm) HCFC-123, HCFC-124, HCFC-142b, or PFH for 2 hours. Urine samples were collected for 24 hours. The rats were killed 0 or 24 hours after exposure and the tissue distribution of the compounds and their metabolites was determined by gas chromatography and fluorine-19 nuclear magnetic resonance spectroscopy. HCFC-123, HCFC-124, HCFC-142b, and PFH were detected in all tissues of rats killed immediately after exposure. 2-Chloro-1,1,1-trifluoroethane (75887) (HCFC-133a) and 2-chloro-1,1-difluoroethylene (359104) were detected in the livers of rats exposed to HCFC-123. HCFC-133a was also detected in the kidneys. Most tissue concentrations of the halocarbons and metabolites were below the detection limit in rats examined 24 hours post exposure. Rats exposed to HCFC-123 and HCFC-124 excreted trifluoroacetic-acid (76051) (TFA) in their urine. Rats exposed to HCFC-142b excreted chlorodifluoroacetic-acid. No PFH metabolites were detected. F344-rats were exposed to 0 to 25,0O0ppm HCFC-123 for 2 to 4 hours. They were killed at various times up to 24 hours after exposure and the urine, blood, and tissues were taken for HCFC-123, TFA, and HCFC-133a analysis. The data were fit to the Hoover physiologically based pharmacokinetic model. Blood TFA concentrations increased during exposure and for up to 5 hours afterwards before slowly decreasing. The metabolism of HCFC-123 to TFA and HCFC-133a became saturated at 2,000ppm HCFC-123. The authors conclude that HCFC-133a may be a useful marker for pharmacokinetic modeling of HCFC-123.

Abstract  Superhydrophobic cotton textiles are prepared by a simple, one-step and inexpensive phase separation method under ambient conditions by which a layer of polymethylsilsesquioxane (PMSQ) nanostructures is covered onto the cellulose fibers. By changing the silane precursor concentration, PMSQ nanostructures with various shapes, morphologies and sizes were fabricated. Nanostructures were characterized using SEM, EDS, and attenuated total reflectance FTIR. The wettability of the modified cellulose surfaces was characterized with contact-angle goniometry and sliding angle technique, respectively. The water contact angle of modified cotton is measured to be higher than 150°, which is high enough to exhibit the lotus effect as a result of the superhydrophobicity. Tunable water-repellent properties of the fabric are also demonstrated, with sliding contact angles varying from "sticky" to "slippery" depending upon different nanostructures on the surface of the fibers. It is expected that this simple technique will accelerate the large-scale production of superhydrophobic cellulosic materials with new industrial applications.

Abstract  Layer-by-layer covalent assembly of an oligoimide on an anhydride- derivatized silicon dioxide surface is investigated using supercritical carbon dioxide (SCCO2) as the depositing medium. The deposited films were characterized by X-ray photoelectron spectroscopy (XPS), ellipsometry (VASE), UV-visible spectroscopy, electrochemical impedance spectroscopy, nano indentation, and atomic force microscopy (AFM) and the properties of the films compared with those of an oligoimide deposited on amine-derivatized surfaces. Films formed on the anhydride surface are more uniform and stable possibly because the silane precursor for the anhydride is anchored to the surface through two (-Si-O-Si-) tripods. XPS results indicate that the interfacial reaction resulting in amide formation is almost complete in the case of the anhydride, but not in the case of the amine. We infer that the twin tripods linking the anhydride group to the surface may have improved the accessibility of the functional groups for immobilization of the next layer, thereby contributing to the better quality.

Abstract  Toxic degradation products are formed from a range of old and modern anesthetic agents. The common element in the formation of degradation products is the reaction of the anesthetic agent with the bases in the carbon dioxide absorbents in the anesthesia circuit. This reaction results in the conversion of trichloroethylene to dichloroacetylene, halothane to 2-bromo-2-chloro-1,1-difluoroethylene, sevoflurane to 2-(fluoromethoxy)-1,1,3,3,3-pentafluoro-1-propene (Compound A), and desflurane, isoflurane, and enflurane to carbon monoxide. Dichloroacetylene, 2-bromo-2-chloro-1,1-difluoroethylene, and Compound A form glutathione S-conjugates that undergo hydrolysis to cysteine S-conjugates and bioactivation of the cysteine S-conjugates by renal cysteine conjugate beta-lyase to give nephrotoxic metabolites. The elucidation of the mechanisms of formation and bioactivation of degradation products has allowed for the safe use of anesthetics that may undergo degradation in the anesthesia circuit.

Abstract  1. We have previously shown that toluene dose-dependently inhibits recombinant N-methyl-D-aspartate (NMDA) receptors at micromolar concentrations. This inhibition was rapid, almost complete and reversible. The NR1/2B combination was the most sensitive receptor subtype tested with an IC(50) value for toluene of 0.17 mM. 2. We now report on the effects of other commonly abused solvents (benzene, m-xylene, ethylbenzene, propylbenzene, 1,1,1-trichlorethane (TCE) and those of a convulsive solvent, 2,2,2-trifluoroethyl ether (flurothyl), on NMDA-induced currents measured in XENOPUS oocytes expressing NR1/2A or NR1/2B receptor subtypes. 3. All of the alkylbenzenes and TCE produced a reversible inhibition of NMDA-induced currents that was dose- and subunit-dependent. The NR1/2B receptor subtype was several times more sensitive to these compounds than the NR1/2A subtype. 4. The convulsant solvent flurothyl had no effect on NMDA responses in oocytes but potently inhibited ion flux through recombinant GABA receptors expressed in oocytes. 5. Overall, these results suggest that abused solvents display pharmacological selectivity and that NR1/2B NMDA receptors may be an important target for the actions of these compounds on the brain.