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1.
Summary A sensitive method has been developed for analysis of trace amounts of arsenic in biological materials using the heteropoly blue method. The method employs a closed apparatus and a nitrogen atmosphere, and allows the detection of arsenic in ppm concentration using samples of 100 mg.
Presented at the 6th Annual Northeast Regional Meeting of the American Chemical Society, Burlington, Vermont, August 19, 1974. 相似文献
Zusammenfassung Eine empfindliche Methode zur Bestimmung von Arsenspuren in biologischem Material im Wege der Molybdänblaumethode wurde ausgearbeitet. Man arbeitet dabei in einer geschlossenen Apparatur in Stickstoffatmosphäre und kann so in 100-mg-Proben Arsenkonzentrationen in der Größenordnung von ppm bestimmen.
Presented at the 6th Annual Northeast Regional Meeting of the American Chemical Society, Burlington, Vermont, August 19, 1974. 相似文献
2.
Selman A. Berger 《Mikrochimica acta》1982,77(5-6):423-431
Summary A semi-automatic microliter sample injector with an 8-way motor-driven rotary valve was constructed for a conventional pneumatic nebulizer. After a 40-l sample was injected into an injection tee with a micro-syringe, nebulization and flushing the sample pathway with water followed by argon were automatically executed. An automatic peak detector/integrator was employed in each channel of a three-channel spectrometer for simultaneous multielement analysis. The relative standard deviation of the peak height for 1g Zr/ml was 1.7% and measuring time of one sample was about 1 min. Detection limits were 2 to 6 times higher than those in continuous feeding.
Halbautomatische Injektion von Mikroliter-Proben in ein induktiv gekoppeltes Plasma zwecks simultaner Multielementanalyse
Zusammenfassung Ein halbautomatischer Injektor für Mikroliterproben mit einem motorgetriebenen 8-Weg-Ventil für ein konventionelles Vernebelungsgerät wurde konstruiert. Nachdem eine 40-l-Probe mit einer Mikroinjektionsspritze in ein Injektions-T-Stück eingeführt ist, erfolgt automatisch Vernebelung, dann Spülung des Probenweges zunächst mit Wasser, dann mit Argon. Ein automatischer Spitzen-Detektor/Integrator in jedem der drei Kanäle des Spektrometers ermöglicht die gleichzeitige Multielementanalyse. Die rel. Standardabweichung der Spitzenhöhe für 1g Zr/ml betrug 1,7%, die Zeit für die Messung einer Probe ungefähr eine Minute. Die Nachweisgrenzen sind 2- bis 6mal höher als bei kontinuierlicher Zugabe.相似文献
3.
Selman A. Berger 《Mikrochimica acta》1984,84(3-4):275-282
Summary DbPH, a quadridentate chelating agent, was studied as a solvent extraction reagent for Cu(II), Co(II), and Ni(II). In all cases 11 complexes were extracted; however for Cu(II) and Co(II) ion-paired species exist, while for Ni(II) only neutral complexes were extracted. In all cases an extraction efficiency of 35–60% was observed unlike the greater than 90% observed for similar mono-hydrazone derivatives. The steric hindrance probably present in the bis adduct prevented a more efficient extraction.
Presented at the 18th Middle Atlantic Regional Meeting of the American Chemical Society, Newark, New Jersey, May 21, 1984. 相似文献
Diacetyl-bis-(2-pyridyl)hydrazon (DbPH) als Extraktionsmittel für Cu(ll), Co(II) und Ni(II)
Zusammenfassung DbPH bildet mit Cu(II), Co(II) und Ni(II) Komplexverbindungen im Verhältnis 11; diese sind für Cu und Co ionisierbar, im Falle des Ni läßt sich ein neutraler Komplex extrahieren. Die Extraktion erreicht jedenfalls nur 35–60% im Gegensatz zu mehr als 90% bei ähnlich gebauten Monohydrazon-Derivaten. Sterische Hinderung dürfte hierfür die Ursache sein.
Presented at the 18th Middle Atlantic Regional Meeting of the American Chemical Society, Newark, New Jersey, May 21, 1984. 相似文献
4.
Photodynamic therapy of transplantable N-[4-(5-nitro-2-furyl)-2-thiazolyl] formamide-induced tumors engrafted onto Fischer CDF (F-344)/CrlBR rats that had been sensitized with the photosensitizer tin (ll) etiopurpurin dichloride was performed in combination with visible light (approximately equal to 660 nm) emitted by either a continuous wave argon-dye laser or a pulsed, frequency-doubled Nd:Yag laser. Tumor control was assessed either by tumor dry-weight 12 days after treatment or by the palpatory absence of tumor at 60 days after treatment. Both laser sources were effective in creating the desired photodynamic effect. This study demonstrates the potential for the use of a solid-state pulsed laser for photodynamic therapy when used in combination with the tumor sensitizer tin (ll) etiopurpurin dichloride. 相似文献
5.
METALLOPURPURINS and LIGHT: EFFECT ON TRANSPLANTABLE RAT BLADDER TUMORS and MURINE SKIN 总被引:1,自引:0,他引:1
A. R. Morgan G. M. Garbo R. W. Keck L. D. Eriksen S. H. Selman 《Photochemistry and photobiology》1990,51(5):589-592
Purpurins are modified chlorins with photodynamic properties. Their strong absorption in the red region of the visible spectrum makes them candidates for use in photodynamic cancer therapy. A series of metal derivatives of the free base purpurins have been synthesized and shown to cause tumor necrosis in transplantable tumors when exposed to visible light. In the following set of experiments, the effects of two metallo-derivatives (tin and zinc) of two purpurins, octaethylpurpurin (NT2) and etiopurpurin (ET2), and light on the N-[4-(5-nitro-2-furyl)-2-thiazolyl] formamide transplantable tumors in Fischer CDF(F344)/CrlBr rats were studied. The photodynamic activity was assessed by a short term assay using tumor dry weight 12 days after purpurin-PDT as a criterion of response. From these experiments it appears that SnET2 greater than SnNT2 greater than ZnET2 greater than ZnNT2 in photodynamic activity. SnET2 was further characterized by attempting to determine the time interval after systemic injection at which maximum therapeutic effect occurred. These studies shown that 24 h after metallopurpurin injection was the optimum time for treatment of tumors with visible light. In a final set of experiments, the effect of solar light on the skin of hairless mice injected with SnET2 was found to be much less injurious than with hematoporphyrin derivative. 相似文献
6.
Selman Akbulut 《Inventiones Mathematicae》1978,49(3-4):193-198
7.
8.
Alan R. Morgan Dimitris Skalkos George Maguire Ashraf Rampersaud Greta Garbo Rick Keck Steven H. Selman 《Photochemistry and photobiology》1992,55(1):133-136
An improved synthesis of benzochlorins is reported. Demetallation of the meso-hydroxymethylvinyl derivative of octaethylporphyrin, followed by treatment with sulfuric acid results in cyclization to generate the corresponding octaethylbenzochlorin in high yield. Prolonged treatment with acid generates the sulfonated derivative. These sensitizers were shown to be efficient photodynamic agents in vivo. Animals bearing a transplanted N-[4-(5-nitro-2-furyl)-2-thiazoly]formamide induced urothelial tumor were treated with either the benzochlorin or its sulfonated derivative. Irradiation of tumors 24 h later resulted in a significant tumoricidal effect in a short term assay. We conclude that benzochlorins warrant further examination as potential agents for use in photodynamic therapy. 相似文献
9.
A. F. M. Suaib Akhter Tawsif Zaman Arnob Ekra Binta Noor Selman Hizal Al-Sakib Khan Pathan 《Entropy (Basel, Switzerland)》2022,24(11)
The popularity of electric vehicles (EVs) is constantly increasing, as they use relatively greener, sustainable energy. However, it is a fact that the charging stations for EVs are yet to meet the demand. It could be a great solution if a peer-to-peer (P2P) charging system could be initiated by anyone who wants to make their garage’s charge points publicly available for commercial purposes, named a home charging station (HCS). In this work, our idea is to bring interested charging stations under a network of nodes and a blockchain-based management system, where the blockchain is responsible for ensuring the authenticity of both the charging stations and charge receiver. A cryptocurrency-based payment system has also been proposed to ensure transactions’ security, integrity, transparency, and immutability. A reputation management system is applied to maintain the quality of service. Miners with high processing power are used to alleviate lagging during block creation, supported by edge servers. The proposed system has been implemented by using virtual machines. A theoretical analysis is presented to assess the compatibility and possible cost requirements to implement the system in a real-world scenario. 相似文献
10.