Quantitation of amphetamine,methamphetamine, and their methylenedioxy derivatives in urine by solid-phase microextraction coupled with electrospray ionization-high-field asymmetric waveform ion mobility spectrometry-mass spectrometry

Amphetamine, methamphetamine, and their methylenedioxy derivatives have been identified and measured in a human urine matrix using solid-phase microextraction (SPME) and high-field asymmetric waveform ion mobility spectrometry (FAIMS) in combination with electrospray ionization (ESI) and mass spectrometric detection (MS). Limits of detection in human urine between 200 pg/mL and 7.5 ng/mL have been achieved. The use of a simple extraction method, SPME, combined with the high sensitivity and selectivity of ESI-FAIMS-MS eliminates the need for chromatographic separation and allows for very rapid sample processing.     

Detection of nine chlorinated and brominated haloacetic acids at part-per-trillion levels using ESI-FAIMS-MS

A combination of electrospray ionization, high-field asymmetric waveform ion mobility spectrometry, and mass spectrometry (ESI-FAIMS-MS) was used for the analysis of a solution containing a mixture of the nine chlorinated and brominated haloacetic acids. For a carrier gas of nitrogen in the FAIMS analyzer, haloacetate anions of the mono- and dihalogenated acids and the decarboxylated anions of three of the trihalogenated acids were detected. No signal was observed for bromodichloroacetic acid (BDCAA) at a dispersion voltage of -3400 V. The addition of a small amount of carbon dioxide to the nitrogen carrier gas resulted in the detection of the pseudomolecular trihaloacetate anions, including BDCA-, and significant increases in sensitivities for the trihalogenated species. The addition of carbon dioxide to the nitrogen carrier gas had little effect on the mono- and dihalogenated anions. Quantitative analysis of the nine haloacetic acids, using flow injection, gave detection limits between 5 and 36 parts-per-trillion in 9/1 methanol/water (v/v) containing 0.2 mM ammonium acetate.     

Effects of operant level, interview with experimenter, and awareness upon verbal conditioning of chronic schizophrenics.

The present research attempted to (a) cross-validate N. D. Vestre's (1961, 1965) findings that medium-operant-level pronouns can be conditioned by "good" in a chronic schizophrenic population, (b) test whether or not high-operant-level pronouns can be conditioned by "good" in a chronic schizophrenic population, and (c) compare the conditionability of high-operant-level with that of medium-operant-level pronouns. It was hypothesized that schizophrenics would be more conditionable following a brief, friendly, personal interview than in the absence of any preconditioning interview. It was expected that awareness of the response-reinforcement contingency would favor conditioning. Both the operant level and interview with experimenter variables were investigated to see whether or not either differentially affected (a) the number of aware Ss and (b) the performance of aware Ss. "Good" functioned as a reinforcer for about 1/4 of the Ss in this study. The most important factor contributing to performance was awareness of the response-reinforcement contingency. Also, reinforcement tended to be more effective when Ss had no (instead of a S-min) preexperimental interview with E. Medium-operant-level pronouns were conditionable, and results of conditionability comparisons between high- and medium-preference pronouns depended upon how performance was measured. The negligible conditionability of high-preference pronouns was discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection of chlorinated and brominated byproducts of drinking water disinfection using electrospray ionization-high-field asymmetric waveform ion mobility spectrometry-mass spectrometry.

The lower limit of detection for low molecular weight polar and ionic analytes using electrospray ionization-mass spectrometry (ESI-MS) is often severely compromised by an intense background that obscures ions of trace components in solution. Recently, a new technique, referred to as high-field asymmetric waveform ion mobility spectrometry (FAIMS), has been shown to separate gas-phase ions at atmospheric pressure and room temperature. A FAIMS instrument is an ion filter that may be tuned, by control of electrical voltages, to continuously transmit selected ions from a complex mixture. This capability offers significant advantages when FAIMS is coupled with ESI, a source that generates a wide variety of ions, including solvent clusters and salt adducts. In this report, the tandem arrangement of ESI-FAIMS-MS is used for the analysis of haloacetic acids, a class of disinfection byproducts regulated by the US EPA. FAIMS is shown to effectively discriminate against background ions resulting from the electrospray of tap water solutions containing the haloacetic acids. Consequently, mass spectra are simplified, the selectivity of the method is improved, and the limits of detection are lowered compared with conventional ESI-MS. The detection limits of ESI-FAIMS-MS for six haloacetic acids ranged between 0.5 and 4 ng/mL in 9:1 methanol/tap water (5 and 40 ng/mL in the original tap water samples) with no preconcentration, derivatization, or chromatographic separation prior to analysis.     

In vivo and in vitro biotransformation of the lithium salt of gamma-linolenic acid by three human carcinomas

Lipid metabolism has been considered recently as a novel target for cancer therapy. In this field, lithium gamma-linolenate (LiGLA) is a promising experimental compound for use in the treatment of human tumours. In vivo and in vitro studies allowed us to assess the metabolism of radiolabelled LiGLA by tumour tissue and different organs of the host. In vitro studies demonstrated that human pancreatic (AsPC-1), prostatic (PC-3) and mammary carcinoma (ZR-75-1) cells were capable of elongating GLA from LiGLA to dihomo-gamma-linolenic acid (DGLA) and further desaturating it to arachidonic acid (AA). AsPC-1 cells showed the lowest delta5-desaturase activity on DGLA. In the in vivo studies, nude mice bearing the human carcinomas were given Li[1-(14)C]GLA (2.5 mg kg(-1)) by intravenous injection for 30 min. Mice were either sacrificed after infusion or left for up to 96 h recovery before sacrifice. In general, the organs showed a maximum uptake of radioactivity 30 min after the infusion started (t = 0). Thereafter, in major organs the percentage of injected radioactivity per g of tissue declined below 1% 96 h after infusion. In kidney, brain, testes/ovaries and all three tumour tissues, labelling remained constant throughout the experiment. The ratio of radioactivity in liver to tumour tissues ranged between 16- and 24-fold at t = 0 and between 3.1- and 3.7-fold at 96 h. All tissues showed a progressive increase in the proportion of radioactivity associated with AA with a concomitant decrease in radiolabelled GLA as the time after infusion increased. DGLA declined rapidly in liver and plasma, but at a much slower rate in brain and malignant tissue. Seventy-two hours after the infusion, GLA was only detected in plasma and tumour tissue. The sum of GLA + DGLA varied among tumour tissues, but it remained 2-4 times higher than in liver and plasma. In brain, DGLA is the major contributor to the sum of these fatty acids. Data showed that cytotoxic GLA and DGLA, the latter provided either by the host or by endogenous synthesis, remained in human tumours for at least 4 days.     

Delayed hydrogen embrittlement in Zr-2.5 wt % Nb

Delayed failures at welds in components of Zi-2.5 wt % Nb are attributed to zirconium hydride forming at the root of a notch adjacent to the welds. Residual tensile stresses provide the driving force for growth of the hydride. The observed rate of growth is considerably higher than the rate calculated by techniques which give good quantitative agreement with experiments at about 575 K. Failures of the type studied here are inhibited by stress relief of the component in question.     

The bauschinger effect in Zircaloy-2

The Bauschinger effect in Zircaloy-2 has been investigated at room temperature using (a) specimens cut from the L and ST directions of a thick, rolled slab, and (b) specimens machined from swaged rod. The blocks of material, from which the slab specimens were cut, received compressive prestrains of up to 3.8%, in either the L or ST direction, prior to the tensile specimens being machined from them. The slab specimens were deformed in tension using a computerized Instron, while the swaged rod specimens were deformed in tension/compression using a prototype, MTS Alpha System.A large Bauschinger effect, manifested by a reduction in the yield stress and by permanent softening, was observed. The magnitude of the reduction in the yield stress depended on the magnitude and direction of the prestrain, and on crystallographic texture, and is clearly large enough to influence design and fabrication of reactor-core components.The data from (b) have been analyzed by four different techniques to obtain estimates of the mean back stress which is responsible for the Bauschinger effect in Zircaloy-2. From a comparison of those values with a theoretical estimate based on the analysis of Brown and Clarke, it is concluded that the second phase (Ni,Cr,Fe) particles in Zircaloy-2 are not responsible for the effects observed. It is suggested that the Bauschinger effect is a direct consequence of crystallographic texture and the limited number of deformation modes which can occur in hep zirconium alloys.     

Vicryl-mesh wrap for the implantation of hydroxyapatite orbital implants: an animal model

OBJECTIVE: To evaluate host fibrovascularization of hydroxyapatite orbital implants wrapped in sclera or in Vicryl (polyglactin 910) mesh in a rabbit model. NUMBERS: Eight adult New Zealand white rabbits that received hydroxyapatite orbital implants wrapped in homologous donor sclera (four animals) or Vicryl mesh (four animals). INTERVENTIONS: The rabbits had one eye enucleated and then received a 12-mm hydroxyapatite implant wrapped in sclera or Vicryl mesh. Magnetic resonance imaging (MRI) and bone scintigraphy were done to assess host fibrovascularization of the implant 4, 8, 12 and 20 weeks after implantation. Two animals (one in each group) were killed at each of these times, and the implant was removed for histopathological examination. MAIN OUTCOME MEASURES: Enhancement on MRI, uptake on bone scintigraphy, fibrovascularization seen on histopathological examination. RESULTS: The degree of fibrovascularization was substantial in all the specimens but appeared greater in the Vicryl-mesh-wrapped implants in the first 12 weeks after implantation on both histopathological and MRI studies. At 20 weeks these findings were similar in the two groups. A granulomatous foreign-body giant-cell reaction to both the Vicryl mesh and the implant itself was present up to 8 weeks after implantation. Bone scans showed only grade 1+ activity in all the implants. CONCLUSIONS: Host fibrovascularization in the rabbit appears to occur to a greater degree in Vicryl-mesh-wrapped hydroxyapatite implants than in those wrapped in donor sclera during the first 12 weeks after implantation. Vicryl mesh appears to be an acceptable alternative wrap for the hydroxyapatite implant, eliminating the need for donor sclera and its potential risks of transmissible diseases.