In situ analysis of solvents on breath and blood: a selected ion flow tube mass spectrometric study

We report measurements of residual vapour levels of xylenes and trimethylbenzenes, present following a floor re-surfacing procedure, using the technique of selected ion flow tube mass spectrometry (SIFT-MS). A subject exposed to controlled amounts of xylene and mesitylene was monitored by direct breath exhalation over a 4-hour period after exposure to the volatile organic compounds (VOCs) had stopped. The headspace gases above 5 mL blood samples taken over this period were also monitored. The decays of the solvent levels with time were fitted to a two-compartment model with residence times for xylene and mesitylene of 0.37 h and 0.38 h, respectively (compartment one) and 2.5 h and 2.8 h, respectively (compartment two).     

Analyses of Stemona alkaloids in Stemona tuberosa by liquid chromatography/tandem mass spectrometry

Alkaloid profiles in Stemona tuberosa were found to be highly variable. Six Stemona alkaloids isolated from the plant were subjected to on-line high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI-MS) and tandem mass spectrometry (MS/MS) analyses. Their fragmentation patterns and products were useful for their characterization. The LC/MS fingerprints of these alkaloids, though variable among samples, could provide an overall characterization of the authenticity and quality of this species and help to differentiate it from S. japonica and S. sessilifolia, as all three species are recognized as genuine sources of the herb Radix Stemonae in the Pharmacopoeia of the People's Republic of China.     

Determination of the configuration of histrelin,and LHRH analog,by chiral capillary gas chromatography

Summary Summary The assigned chirality at each center of the synthetic nonapeptide histrelin (L-pyroglutamyl-L-histidyl-L-tryptophyl-L-seryl-L-tyrosyl-D-N^im-benzyl-histidyl-L-leucyl-L-arginyl-L-proline-ethylamide) was verified using chiral gas chromatography. The procedure involved acid hydrolysis of histrelin to the constituent amino acids, derivatization as the N-pentafluoropropionyl/isopropyl esters and the analysis of the mixture using a commercially available 25m chiral capillary column (Chirasil-L-Val). There was no significant difference in the retention time of the amino acids obtained from the hydrolysate mixture when compared to the appropriate standards. Additionally, the hydrolysate was spiked with the D and L amino acids to prove the identity of closely eluting peaks. Luteinizing hormone-releasing hormone     

On-line nuclear orientation and relaxation studies of Cs isotopes

The hyperfine field of CsFe has been measured to be (+)40.8(0.7)T, using the technique of on-line low temperature nuclear orientation. The time dependent relaxation of¹²¹Cs^m Fe has also been investigated using a new technique, giving a Korringa constant C_k of 0.059 (15) sK. From this, an effective relaxation time of 3.0 (0.8)s can be deduced for the short lived¹¹⁸Cs^m(T_1/2=17s). This value has then been used to extract the magnetic moment of¹¹⁸Cs^m to be |μ|=5.4 (1.1) nm.     

Superelasticity and stability of a shape memory alloy hexagonal honeycomb under in-plane compression

Nitinol (NiTi) shape memory alloy honeycombs, fabricated in low densities using a new brazing method [Grummon, D., Shaw, J., Foltz, J., 2006. Fabrication of cellular shape memory alloy materials by reactive eutectic brazing using niobium. Materials Science and Engineering A 438–440, 1113–1118], recently demonstrated enhanced shape memory and superelastic properties [Shaw, J. A., Grummon, D. S., Foltz, J., 2007b. Superelastic NiTi honeycombs: Fabrication and experiments. Smart Materials and Structures 16, S170–S178] by exploiting kinematic amplification of thin-walled deformations. The realization of such adaptive, light-weight cellular structures opens interesting possibilities for design and novel applications. This paper addresses the consequent need for design and simulation tools for engineers to make effective use of such structures by, as a first step, analyzing the multi-scale stability aspects of the superelastic behavior of a particular hexagonal, thin-walled, SMA honeycomb under in-plane compression. An in-depth parameter study is performed of the influence of different material laws on the behavior of honeycombs of finite and infinite extent with perfect and imperfect initial geometries. A finite element-based simulation is presented that credibly captures the behavior seen in experiments.     

A single-mode KrF laser

Single-mode operation of a KrF laser oscillator has been achieved for the first time. The laser medium is pumped by an electron beam which allows excitation for a much longer duration than with discharge pumping. The long excitation time, together with the use of a short oscillator cavity with a low single-pass gain, allows many roundtrips before saturation is reached. This makes line-narrowing easier and single-mode operation has been achieved using only two intracavity etalons.Technical Research Centre of Finland, Helsinki, Finland     

Palladium(II)-catalyzed intramolecular aminoacetoxylation of sugar derived alkenyl tosylsulfonamide: Total synthesis of l-deoxyallonojirimycin

Palladium catalyzed intramolecular aminoacetoxylation of d-ribose derived alkenyl tosylsulfonamide to deliver l-deoxyallonojirimycin in an overall yield of 19%. The preliminary screening of l-deoxyallonojirimycin against carbohydrate processing enzymes showed moderate inhibitory activity against α-glucosidase (yeast) and α-mannosidases.     

Natural convection in a partitioned enclosure heated from below

Cubic spline collection numerical method has been developed to determine two dimensional natural convection in a partitioned enclosure heated from below. The both sides of impermeable partition are considered to have continuity in heat flux and temperatures. The governing equations are solved with aid of the SADI procedure. Parametric studies of the effects of the partition and Rayleigh number on the fluid flow and temperature fields have been performed. Results show that the location of the partition and Rayleigh number have a significant influence on the flow and heat transfer characteristics.

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Freie Konvektion in einem von unten beheizten, unterteiltem Hohlraum

Zusammenfassung Eine numerische dreidimensionale SplineMethode zur Berechnung der zweidimensionalen Naturkonvektion in einem von unten beheizten, unterteiltem Hohlraum wird vorgestellt. Der Wärmestrom und die Temperatur auf beiden Seiten der undurchlässigen Trennwand werden als konstant betrachtet. Mit Hilfe der SADI-Prozedur werden die beschreibenden Gleichungen gelöst. Über den Einfluß der Unterteilung und der Rayleigh-Zahl auf die Strömung des Fluids und das Temperaturfeld wird eine Parameter-Studie durchgeführt. Die Ergebnisse zeigen, daß die Anordnung der Unterteilung und die Rayleigh-Zahl einen entscheidenden Einfluß auf das Wärmeübertragungsverhalten haben.

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Nomenclature A aspect ratio=L/H - g gravitational acceleration - H enclosure height - H₁ distance between the top wall of enclosure and the partition - H₂ distance between the bottom wall of enclosure and the partition - k thermal conductivity of fluid - L enclosure length - m number of vertical grid lines - n number of horizontal grid lines - Nu Nusselt number - P pressure - Pr Prandtl number - Q heat transfer across enclosure - Ra Rayleigh number based onH - t time - T dimensional temperature - T _H temperature of warm horizontal wall - T _L temperature of cold horizontal wall - T ₀ average temperature=T(_H+T_L)/2 - T temperature difference between the hot and cold wall =T _H–T_L - u, U dimensional and dimensionless horizontal velocity - , V dimensional and dimensionless vertical velocity - x, X dimensional and dimensionless horizontal coordinate - y, Y dimensional and dimensionless vertical coordinate - fluid thermal diffusivity - coefficient of thermal expansion - viscosity - kinematic viscosity=/g9 - density - , dimensional and dimensionless stream function - dimensionless temperature - , dimensional and dimensionless vorticity - dimensionless time     

Effects on feeding rate and biomarker responses of marine mussels experimentally exposed to propranolol and acetaminophen

Environmental risk assessments of human pharmaceuticals and other ‘emerging contaminants’ should integrate both population-relevant endpoints and biomarkers of potential modes of action in a range of species. Adult Mytilus galloprovincialis were exposed to the beta-adrenergic receptor blocker propranolol or to the anti-inflammatory drug acetaminophen (paracetamol), both commonly used therapeutic drugs present in aquatic ecosystems. Mussels were exposed under semi-static conditions for 10 days to either acetaminophen (CAS number 103-90-2; mean measured concentrations 23 and 403 μg/L) or propranolol hydrochloride (CAS number 318-98-9; mean measured propranolol concentrations 11 and 147 μg/L) at 15 ± 1 °C sea water. Feeding rate was assessed as an indicator of general toxicity. For propranolol, the 10-day no-observed effect concentration (^{feeding rate}NOEC) and lowest observed effect concentration (^{feeding rate}LOEC) were 11 and 147 μg/L, respectively. For acetaminophen, feeding rate was increased at both 23 and 403 μg/L, suggesting a 10-day ^{feeding rate}NOEC of 403 μg/L. Primarily, phase I carboxylesterase (CbE), phase II glutathione S-transferase (GST) and the anti-oxidant catalase activities were evaluated in digestive gland. Gill GST and acetylcholinesterase (AChE) activities were also measured. Lipid peroxidation (LPO) levels were measured in both tissues to assess oxidative stress. Some enzymatic activities in liver were also reduced after propranolol exposure whilst acetaminophen enhanced them (CbE p < 0.05). Acetaminophen exposure significantly increased hepatic LPO levels and inhibited AChE activity in gill (10-day NOEC and LOEC of 23 and 403 μg/L, respectively), whereas propranolol (11 μg/L) enhanced gill GST.