Vapor generation by UV irradiation for sample introduction with atomic spectrometry

Volatile species of the conventional hydride-forming elements (As, Bi, Sb, Se, Sn, Pb, Cd, Te), Hg, transition metals (Ni, Co, Cu, Fe), noble metals (Ag, Au, Rh, Pd, Pt), and nonmetals (I, S) were generated following UV irradiation of their aqueous solutions to which low molecular weight carboxylic acids (formic, acetic, propionic) had been added. Free radicals arising from photodissociation of the latter provide a new and useful alternative to the common methods of chemical/electrochemical vapor generation techniques for the determination of these analytes by atomic spectrometry. Quantitative estimates of the efficiencies of these generation processes were not undertaken, although calculated signal-to-background ratios (>1500 for 5 ng/mL As, Sb, Bi, Se, and Te; 20 for 10 ng/mL Sn, Cu, Rh, Au, Pd, Pt, and Cd; 2400 for 1 ng/mL Hg; and 1000 for Co using ICP-TOF-MS detection) do provide clear evidence of the efficacy of this approach for sample introduction. In the case of Ni and Se, the tetracarbonyl and alkylated selenium compounds have been identified, respectively.     

Development of the Eco-Cascade- cell reactor

The development of multicompartment rotating cylinder electrode reactors for the removal of metal from aqueous solutions is described. Such reactors approximate to a cascade of continuously stirred tank reactors and the results illustrate that, for electrodeposition of copper powder from acid sulphate solutions, high overall conversions (about 98%) may be realised, with low exit metal concentrations (about 1 mg dm^–3) and reasonable current efficiencies (65–87%).Nomenclature A electroactive surface area (cm²) - C _in inlet concentration of metal (mg dm^–3) - C _out outlet concentration of metal (mg dm^–3) - C _reactor reactor concentration of metal (mg dm^–3) - f _R fractional conversion - (f _R)n overall fractional conversion - F Faraday=96 500 (C mol^–1) - I _L limiting current (A) - k _l mass transfer coefficient (cms^–1) - m weight of metal (g) - M molecular weight of metal - n number of reactor elements in the cascade - N volumetric flow rate (cm³ s^–1) - z electron change - dm/dt rate of removal of metal (gs^–1) This paper was presented, in part, at the Electrochemical Reaction Engineering Symposium, Southampton University, April (1979).     

Formation oftrans-12,13-epoxy-9-hydroperoxy-trans-10-octadecenoic acid from 13-L-hydroperoxy-cis-9,trans-11-octadecadienoic acid catalyzed by either a soybean extract or cysteine-FeC13

A soybean extract or an ethanolic solution of cysteine and ferric chloride catalyzed the conversion of 13-L-hydroperoxy-cis-9,trans-11-octadecadienoic acid to numerous products among which wastrans-12,13-epoxy-9-hydroperoxy-trans-10-octadecenoic acid. When this fatty acid was treated further with the cysteine-ferric chloride solution, 9-hydroxy-12,13-epoxy-10-octadecenoic and 9-oxo-12,13-epoxy-10-octadecenoic acids were formed. Thus,trans-12,13-epoxy-9-hydroperoxy-trans-10-octadecenoic acid probably is an intermediate in the formation of the latter two compounds. Additionally, theerythro andthreo isomers oftrans-12,13-epoxy-11-hydroperoxy-cis-9-octadecenoic acid tenatatively were identified as products. Presented in part at the 13th World Congress, International Society for Fat Research, Marseilles, France, August 30-September 4, 1976, and the AOCS Meeting, Chicago, September 1976.     

The psychotherapeutic relationship.

This paper attempts an exhaustive review of the literature on the psychotherapeutic relationship. The nature of the ideal psychotherapeutic relationship is defined and approximations of this ideal are shown to correlate positively with various measures of patient progress in the therapeutic enterprise. Other correlates of good therapeutic relationships are then explored: patient variables, therapist variables, therapist-patient similarity, and technique variables. In all these areas, significant correlations are found, though not as often as one might expect. The research on therapist variables is especially disappointing, while patient variables seem to be quite good predictors of the quality of the ensuring patient-therapist relationship. Methodological issues are considered throughout the paper. (72 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Magnetic and superconducting properties of niobium oxides

Low temperature magnetic susceptibilities of niobium oxides have been measured. A homogeneous sample of NbO prepared by arc melting and checked by using X-ray and metallographic techniques exhibits no ferromagnetism but becomes superconducting at 1.20°K.     

Distribution of Norditerpene Alkaloids in Tall Larkspur Plant Parts Through the Growing Season

Previous research showed that toxic and total alkaloid pools in tall larkspur (Delphinium barbeyi) increased during early growth, then declined precipitously during the late flower and pod stage of growth. The objective of this study was to measure the concentration and pools of toxic and total alkaloids in tall larkspur plant parts, including roots, and to evaluate the changes in these pools over the growing season as an estimate of diterpenoid alkaloid kinetics in tall larkspur. Twenty entire plants were harvested at each phenological stage: beginning of growth in the spring, early flower, early pod, late pod, and senescence. The plants were separated into their respective parts, freeze-dried, extracted, and analyzed for toxic and total alkaloid concentration, and alkaloid pools were calculated. Concentration of toxic and total alkaloids in leaves and stems declined as the plants matured, while concentration in flowers and pods increased (P < 0.004). Concentration of alkaloids in the root declined in the early growth, then increased at the end of the season (P = 0.002). Alkaloid pools in the root decreased during early growth, with a corresponding increase of pools in foliar parts. In the late flower and pod stage, alkaloid pools in the leaves and stems declined rapidly, while the pool in the crown and roots tended to increase.     

UV vapor generation for determination of selenium by heated quartz tube atomic absorption spectrometry

A new vapor generation technique utilizing UV irradiation coupled with atomic absorption for the determination of selenium in aqueous solutions is described. In the presence of low molecular weight organic acid solutions, inorganic selenium(IV) is converted by UV irradiation to volatile selenium species, which are then rapidly transported to a heated quartz tube atomizer for detection by atomic absorption spectrometry. Optimum conditions for photochemical vapor generation and interferences from concomitant elements were investigated. Identification of the volatile products using cryotrapping GC/MS analysis revealed that inorganic selenium(IV) is converted to volatile selenium hydride, selenium carbonyl, dimethyl selenide, and diethyl selenide in the presence of formic, acetic, propionic, and malonic acids, respectively. In acetic acid solution, the efficiency of generation was estimated to be 50 +/- 10%. No interference from Ni(2+) and Co(2+) at concentrations of 500 and 100 mg L(-)(1), respectively, was evident. A detection limit of 2.5 microg L(-)(1) and a relative sensitivity of 1.2 microg L(-)(1) (1% absorption) with a precision of 1.2% (RSD, n = 11) at 50 microg L(-)(1) were obtained.     

The role of the self-concept and the social context in determining the behavior of power holders: Self-construal in intergroup versus dyadic dispute resolution negotiations.

In this work, the authors explored how a person's view of himself or herself might determine his or her use of power in a complex dispute resolution negotiation. In 3 studies of asymmetric power in negotiations, the authors demonstrated that the impact of power on motivation and behavior is moderated by both a person's self-view and the social context. In Study 1, the results revealed that in a one-on-one dispute, powerful individuals primed to hold an interdependent (as opposed to independent) self-construal are more generous in resolving their disputes with low-powered opponents. Study 2 replicated this finding but revealed a different pattern in intergroup disputes, in which powerful interdependent teams of negotiators are actually less generous than are independent teams. Study 3 provided a conceptual replication of Study 2, with the use of chronic measures of self-construal and self-reported measures of behavior. Results suggest that an interdependent self-construal may lead to a more benevolent use of power in dyadic conflicts but more exploitive uses of power in intergroup conflicts. Implications for the understanding of power and self-construal are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Active Integrated Antenna Design Using a Contact-Less, Proximity Coupled, Differentially Fed Technique

A novel contact-less, differential feeding technique suitable for integrated active antenna design is demonstrated. This technique utilizes an odd mode signal to generate fringing fields on either side of a microstrip gap under the antenna. This allows electromagnetic energy to be efficiently coupled from the transmission lines to the radiating antenna. In a balanced integrated antenna amplifier configuration, the proposed non-contact feeding method removes the need for any balun or power combining network. Hence in theory, a compact RF front-end design with lower losses can be realized. This feeding method has been successfully applied to the design of simple passive microstrip patch antennas and active integrated antennas (AIA). Simulated and measured results are also included to validate the proposed feeding concept and antenna designs. The performance of the proposed differential feeding technique on a simple microstrip patch antenna has been systematically studied. The study suggests that the proposed proximity method is broadband in nature, allowing antennas operating at different resonant frequencies to be swapped without the need to change the feed dimensions and without degrading the matching performance