Multinuclear magnetic resonance spectroscopy and crystal structures of iodo-bridged dinuclear Pt(II) complexes with amines

Complexes of the types cis-Pt(amine)₂I₂ were transformed into the iodo-bridged dimers, which were characterized mainly by multinuclear (¹⁹⁵Pt, ¹H and ¹³C) magnetic resonance spectroscopy. For bulby amines, the dinuclear species were synthesized directly from K₂[PtI₄]. Compounds with several primary aliphatic and cyclic amines and two secondary amines were studied. In ¹⁹⁵Pt NMR, two signals were observed between −3899 and −4080 ppm in acetone. These species were assigned to the cis and trans dinuclear compounds I(amine)Pt(μ-I)₂PtI(amine). We suggest that the most shielded compound is the trans isomer. The difference between the two isomers is 12-13 ppm for the primary amine system and 26-27 ppm for the two secondary amines. There seems to be a slight dependence of the proton affinity in the gas phase of the amine (linear amines) with the δ(Pt) chemical shifts of the dinuclear Pt(II) compounds. The ²J(¹⁹⁵Pt-¹HN) coupling constants are slightly larger for the trans isomers (average 67 Hz, vs. 56 Hz). The ³J(¹⁹⁵Pt-¹H) coupling constants were detected only for the dimethylamine compounds, 46 Hz (trans) and 44 Hz (cis). In ¹³C NMR, the values of ²J(¹⁹⁵Pt-¹³C) and ³J(¹⁹⁵Pt-¹³C) were also found to be very slightly larger for the trans complexes (average 19 and 25 Hz vs. 15 and 18 Hz). The structures were confirmed by X-ray diffraction studies of the n-butylamine and diethylamine compounds. The two crystals were those of the trans dinuclear complexes.     

When carnivores collide: a review of studies exploring the competitive interactions between bobcats Lynx rufus and coyotes Canis latrans

1. Bobcats Lynx rufus and coyotes Canis latrans are two widespread mesopredators with a complex history of sympatry. The competitive interactions between these species are of interest to biologists due to the furbearer status of bobcats, the recent range expansion of coyotes, and the recolonisation of several parts of North America by bobcats following their extirpation. Although studies exploring the dynamics and competition between bobcats and coyotes span decades, there is a lack of understanding regarding what factors influence exploitative or interference competition, and what methodologies are conducive to identifying these types of competition.
2. We gathered a comprehensive list of research papers (n = 41) exploring bobcat–coyote competitive interactions in North America. From them, we collected the following: study site characteristics, number and types of research methods, number and types of metrics explored, history of sympatry of the two species at the study location, presence of apex predators, and documentation of interference and/or exploitative competition.
3. Using generalised linear models, we determined that interference competition between bobcats and coyotes was observed primarily in open habitat. However, habitat heterogeneity, the number of research methods and metrics used, presence of an apex predator, and history of sympatry could not be used to predict the occurrence of interference competition. Studies that included diet overlap were less likely to observe interference competition than studies that used other metrics to infer competition.
4. Competitive interactions between coyotes and bobcats are largely a function of prey availability. Our findings suggest that habitat type may be a surrogate for prey availability, which many researchers mention, but do not explicitly measure. Future studies investigating bobcat–coyote interactions should include the quantification of prey densities to gain a more comprehensive understanding of the system at large, and should avoid using solely diet or habitat overlap as metrics to assess competition.

     

Über die chemische und photodynamische Wirkung von Neutralrot auf die Rotationsströmung beiHordeum vulgare L.

Zusammenfassung Die chemische und photodynamische Neutralrotwirkung auf die Rotationsströmung wurde in Abhängigkeit von den Absorptionsmaxima des Farbstoffes untersucht. Als Material dienten die Wurzelhaare der Gerste (Hordeum vulgare L.). Die Wurzelhaare wurden mit monochromatischem Licht verschiedener Wellenlängen (455, 499, 524, 553 und 654 nm) belichtet, dessen Wirkung auf die Kontrolle (nicht angefärbte Wurzelhaare) und die angefärbten Wurzelhaare getrennt verfolgt wurde.Die Kontrollwerte ergaben, daß das monochromatische Licht je nach dessen Wellenlänge eine verschiedene Wirkung auf die Rotationsströmung ausübte. Das blaue (455 nm) und das dunkelgrüne Licht (524 nm) induzierten die betonteste Stimulationswirkung. Das Rotlicht (654 nm) führte zu einer weit geringeren Stimulation der Rotation.Die Neutralrotwirkung war vom Absorptionsspektrum des Farbstoffes abhängig, jedoch mußte bei der Besprechung der Ergebnisse auch das Verhalten der nicht angefärbten Wurzelhaare unter monochromatischer Belichtung beachtet werden. Festzustellen ist, daß die betonteste Rotationshemmung im Dimeren-Bereich des Absorptionsspektrums des Farbstoffes (500 nm) stattfand. Sie ist der durch das Neutralrot induzierten photodynamischen Wirkung zu verdanken. In den Wellenlängen entsprechend der Maximalabsorption der Farbmoleküle (450 nm) und der monomeren Farbkationen (530 nm) war die photodynamische Wirkung schwächer als im Absorptionsbereich der dimeren Farbkationen. Im hellgrünen (V-Bande, 540–550 nm) und besonders im roten Licht (654 nm) fand vorzugsweise ein chemischer Neutralroteinfluß statt.Die erhaltenen Ergebnisse berechtigen zu der Annahme, daß das Neutralrot durch Adsorption labil an die kontraktilen Proteine des Cytoplasmas gebunden vorliegt. Die festgestellte betonte Hemmung im blaugrünen Licht (500 nm) läßt vermuten, daß der in dimerer Form an Proteine adsorbierte Anteil des Neutralrot eine besonders wichtige Rolle beim Zustandekommen des photodynamischen Effektes spielt.

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The chemical and photodynamic action of neutral red on rotational streaming in barley (Hordeum vulgare L.) root hairs

Summary The chemical and photodynamic action of neutral red on rotational streaming was studied in relation with absorption maxima of the dye. The barley (Hordeum vulgare L.) root hairs were employed. They were iluminated with monochromatic light of different wavelengths (455, 499, 524, 553, and 654 nm) and their effect were separately recorded both for control (root hairs without dye) and stained root hairs.The data from the control show, that monochromatic light has a different action on rotational streaming depending of its wavelength. The blue light (455 nm) and the dark green light (524 nm) has brought about a higher stimulation of rotational streaming. The red light (654 nm) has stimulated the rotational streaming in a little extent.The effect of neutral red was in relation with the absorption spectrum of the dye, but the discussion of the results must take into account also the behaviour of the control in the monochromatic light. The data show that the strongest inhibition of rotational streaming took place in the dimere region (500 nm) of the dye absorption spectrum. This inhibition was due to photodynamic action of neutral red. In the wavelengths corresponding to maximum absorption of light by the molecule (450 nm) and monomere (530 nm) of neutral red, the photodynamic action was weaker than in the dimere region of the spectrum. In light-green (540–550 nm) and especially in red (654 nm), only the chemical effect of neutral red was shown.The obtained data show that the neutral red is probably labile adsorbed on the cytoplasmic contractile proteins. The strongest inhibition in blue green light (500 nm) also points out that the proportion of neutral red adsorbed as a dimere on the proteine molecule plays an especial role in the promotion of photodynamic effect.

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Die Unkosten dieser Arbeit wurden von der Akademie der S.R. Rumänien getragen. Für die wertvollen Hinweise und Anleitungen sprechen wir unserem Lehrer, Prof. Dr.Emil pop, den herzlichsten Dank aus.     

Automatic detection of basal cell carcinoma by hyperspectral imaging

The purpose of this study was to test the ability of hyperspectral imaging (HSI) combined with unsupervised anomaly detectors to automatically differentiate basal cell carcinoma (BCC) from normal skin. Hyperspectral images of the face of a female patient with a BCC of the lower lip were acquired using a visible/near-infrared HSI system and two anomaly detection algorithms (Reed-Xiaoli and Reed-Xiaoli/Uniform Target hybrid anomaly detectors) were used to detect pathological tissue from normal skin. The results revealed that the receiver operating characteristic curve of the Reed-Xiaoli/Uniform Target hybrid detector was higher than that of the Reed-Xiaoli detector in the range of false positive rates between 0 and 0.8. The area under curve values were good (0.7074 and 0.8607, respectively) with Reed-Xiaoli/Uniform Target hybrid detector performing better. In conclusion, HSI combined with either of two anomaly detectors can play a promising role in the automated screening of BCC.     

The Effect of ATP (Disodium Salt) upon Rotational Streaming

Through the continuous treatment with various solutions of ATP disodium salt the rotational streaming of the cytoplasma in barley root hairs has been stimulated about 1.2–1.7 times. With the concentrations employed the stimulation of the streaming did not depend on the external ATP supply, but on the initial rate of streaming. It is assumed that the main source of energy supporting the protoplasmic streaming is ATP. Therefore, the results obtained may be interpreted on the basis of variations in ATP content and its degradation products. The differences between initial rates of streaming are supposed to be due to variations of the endogenous ATP level. The ATP taken up probably stimulates the rotational streaming both through the supply of delivered energy and by lowering the cytoplasm viscosity. On the contrary, products of ATP hydrolysis increase the cytoplasm viscosity and induce a lowering or even cessation of the streaming.