ABSORPTIOMETRIC DETERMINATION OF MERCURY Organo-tin -Dithizone Complexes The Colorimetric Determination of Diethyltin and Triethyltin Compounds

It has been demonstrated that some organo-tin compounds react with dithizone. The absorption maximum for the diethyltin -dithizone complex, after being shaken with 10 per cent. trichloroacetic acid, is a t 510 mp, whereas triethyltin does not react under these conditions. In the presence of borate buffer of pH 8.4, diethyltin and triethyltin compounds produce with dithizone absorption maxima a t 485 and 440 mp, respectively. At 510 m p the triethyltin -dithizone complex and dithizone have the same absorption. Based upon these findings and their distribution between chloroform and aqueous media, a method is described for the separation and determination of diethyltin and triethyltin compounds. Interference from other metals is avoided by the use of ethylenediaminetetra-acetic acid. RECENTLY interest has been shown in the biological activity of organo-tin compounds,1 ,2 after reports of their potential use as fungicides,3 as clearing agents in plastics and for the treatment of boils in France.4 A method was required for the determination of the dialkyltin and trialkyltin compounds and for estimating mixtures of these compounds. Although diphenylthiocarbazone (dithizone) is a well known reagent for detecting small amounts of metals, little use has been made of its reactivity with organo-metallic compounds. Miller, Polley and Gould5 and later Miller and Polley6 reported a method for determining mixtures of ethylmercuric and phenylmercuric compounds by using dithizone and stated that several other organo-mercuric compounds reacted with this reagent. Webb, Bhatia, Convin and Sharp7 also published analytical data on the reaction products of dithizone and organo-mercury compounds. In this paper it is shown that dithizone reacts with organo-tin compounds, and a method for the qualitative and quantitative differentiation of mixtures of triethyltin and diethyltin compounds is described. EXPERIMENTAL All optical measurements were made with a Unicam SP600 spectrophotometer. A preliminary investigation showed that , when a solution of diethyltin dichloride was shaken with a chloroform solution of dithizone in the presence of aqueous 10 per cent. trichloroacetic acid, a red colour was produced. Tetraethyltin and triethyltin sulphate did not react under these conditions. On the other hand, when shaken with borate buffer of pH 8-4, triethyltin sulphate gave a yellow colour and diethyltin dichloride an orange colour. Under these conditions neither tetraethyltin, monoethyltin nor stannic chloride produced any change of colour

Laser-UV-microirradiation of interphase nuclei and posttreatment with caffeine: a new approach to establish the arrangement of interphase chromosomes

Laser UV microirradiation of Chinese hamster interphase cells combined with caffeine post-treatment produced different patterns of chromosome damage in mitosis following irradiation of a small area of the nucleus that may be classified in three categories: I) intact metaphase figures, II) chromosome damage confined to a small area of the metaphase spread, III) mitotic figures with damage on all chromosomes. Category III might be the consequence of a non-localized distortion of nuclear metabolism. By contrast, category II may reflect localized DNA damage induced by microirradiation, which could not be efficiently repaired due to the effect of caffeine. If this interpretation is right, in metaphase figures of category II chromosome damage should occur only at the irradiation site. The effect might then be used to investigate neighbourhood relationships of individual chromosomes in the interphase nucleus

Evolutionary game theory in growing populations

Existing theoretical models of evolution focus on the relative fitness advantages of different mutants in a population while the dynamic behavior of the population size is mostly left unconsidered. We here present a generic stochastic model which combines the growth dynamics of the population and its internal evolution. Our model thereby accounts for the fact that both evolutionary and growth dynamics are based on individual reproduction events and hence are highly coupled and stochastic in nature. We exemplify our approach by studying the dilemma of cooperation in growing populations and show that genuinely stochastic events can ease the dilemma by leading to a transient but robust increase in cooperationComment: 4 pages, 2 figures and 2 pages supplementary informatio

Synchronization of organ pipes: experimental observations and modeling

We report measurements on the synchronization properties of organ pipes. First, we investigate influence of an external acoustical signal from a loudspeaker on the sound of an organ pipe. Second, the mutual influence of two pipes with different pitch is analyzed. In analogy to the externally driven, or mutually coupled self-sustained oscillators, one observes a frequency locking, which can be explained by synchronization theory. Further, we measure the dependence of the frequency of the signals emitted by two mutually detuned pipes with varying distance between the pipes. The spectrum shows a broad ``hump'' structure, not found for coupled oscillators. This indicates a complex coupling of the two organ pipes leading to nonlinear beat phenomena.Comment: 24 pages, 10 Figures, fully revised, 4 big figures separate in jpeg format. accepted for Journal of the Acoustical Society of Americ

A passion for respect: On understanding the role of human needs and morality

In the present paper, we stress the importance of the concept respect in a wide variety of social settings and provide a working definition of this concept by emphasizing how respect relates to the act of communicating full recognition to other people on the dimensions of belongingness and morality. Subsequently, in two separate parts, we discuss why respect is so desired and valued. The first part looks at respect as a means to fulfil important human social concerns (“respect as a means to an end”). The second part looks at the potential moral underpinnings of respect and thus interprets “respect as an end in itself.” Finally, it is suggested that both reasons to value respect explain respect effects as a function of the working selfconcept that is salient (i.e., pragmatic versus idealistic self)

A passion for respect: On understanding the role of human needs and morality

In the present paper, we stress the importance of the concept respect in a wide variety of social settings and provide a working definition of this concept by emphasizing how respect relates to the act of communicating full recognition to other people on the dimensions of belongingness and morality. Subsequently, in two separate parts, we discuss why respect is so desired and valued. The first part looks at respect as a means to fulfil important human social concerns (“respect as a means to an end”). The second part looks at the potential moral underpinnings of respect and thus interprets “respect as an end in itself.” Finally, it is suggested that both reasons to value respect explain respect effects as a function of the working selfconcept that is salient (i.e., pragmatic versus idealistic self)

Willing and able: action-state orientation and the relation between procedural justice and employee cooperation

Existing justice theory explains why fair procedures motivate employees to adopt cooperative goals, but it fails to explain how employees strive towards these goals. We study self-regulatory abilities that underlie goal striving; abilities that should thus affect employees’ display of cooperative behavior in response to procedural justice. Building on action control theory, we argue that employees who display effective self-regulatory strategies (action oriented employees) display relatively strong cooperative behavioral responses to fair procedures. A multisource field study and a laboratory experiment support this prediction. A subsequent experiment addresses the process underlying this effect by explicitly showing that action orientation facilitates attainment of the cooperative goals that people adopt in response to fair procedures, thus facilitating the display of actual cooperative behavior. This goal striving approach better integrates research on the relationship between procedural justice and employee cooperation in the self-regulation and the work motivation literature. It also offers organizations a new perspective on making procedural justice effective in stimulating employee cooperation by suggesting factors that help employees reach their adopted goals

No impact of polymorphism in the phosphodiesterase 5A gene in Cavalier King Charles Spaniels on pimobendan-induced inhibition of platelet aggregation response

Background: A variant in the canine phosphodiesterase (PDE) 5A gene (PDE5A: E90K) is associated with decreased concentrations of circulating cyclic guanosine monophosphate (cGMP) and response to PDE5 inhibitor treatment. Pimobendan is a PDE inhibitor recommended for medical treatment of certain stages of myxomatous mitral valve disease (MMVD) in dogs.Hypothesis: PDE5A:E90K polymorphism attenuates the inhibitory effect of pimobendan on in vitro platelet aggregation and increases basal platelet aggregation in Cavalier King Charles Spaniels (CKCS). Selected clinical variables (MMVD severity, sex, age, hematocrit, platelet count in platelet-rich plasma [PRP], and echocardiographic left ventricular fractional shortening [LV FS]) will not show an association with results.Animals: Fifty-two privately owned CKCS with no or preclinical MMVD.Methods: Using blood samples, we prospectively assessed PDE5A genotype using Sanger sequencing and adenosine diphosphate-induced platelet aggregation response (area under the curve [AUC], maximal aggregation [MaxA], and velocity [Vel]) with and without pimobendan using light transmission aggregometry. Dogs also underwent echocardiography.Results: Pimobendan inhibited platelet function as measured by AUC, MaxA, and Vel at a concentration of 10 mu M (P <.0001) and Vel at 0.03 mu M (P <.001). PDE5A:E90K polymorphism did not influence the inhibitory effect of pimobendan or basal platelet aggregation response.Conclusions and Clinical Importance: The PDE5A:E90K polymorphism did not influence in vitro basal platelet aggregation response or the inhibitory effect of pimobendan on platelet aggregation in CKCS. Dogs with the PDE5A:E90K polymorphism did not appear to have altered platelet function or response to pimobendan treatment