Electrochemistry of cyclic triimidazoles and their halo derivatives: A casebook for multiple equivalent centers and electrocatalysis

A family of cyclic triazines, based on the triimidazo[1,2-a:1\u2032,2\u2032-c:1\u2033,2\u2033-e][1,3,5]triazine scaffold, has recently caught attention due to its variegated solid state photoluminescent properties (e.g., crystallization induced emission, fluomechanochromism, dual fluorescence, room temperature ultralong phosphorescence), tuned by proper functionalization of the cyclic core. From an electrochemical point of view, this family of heteroaromatic cyclic triazines is unexplored. A cyclic voltammetry study is here performed aiming to clarify structure/electroactivity relationship. The peculiar molecular structure of this class of molecules offers a multi-approach case study, spanning from multiple equivalent redox site interactions in small hoops (due to ideally C3h symmetry) to carbon-halogen bond reactivity in the presence of catalytic metal electrode surfaces (for \u2013Br and \u2013I derivatives). Results point to a poor heteroannular aromaticity along the rigid, planar cyclotrimer, with each equivalent redox site acting quite independently. An unusually higher electrocatalytic performance of gold with respect to silver electrode for the electrocleavage of carbon-halogen bonds (that decreases by increasing number of halo substituents) is tentatively explained in term of a specific interaction between gold and the nitrogen-rich planar cyclotrimer platform

Microplastics in deep water : a combined GC-MS e FT-IR approach

Microplastics are water-insoluble, solid polymer particles that are 645\u202fmm in size. A lower size boundary has not been defined, but particles below 1\u202f\u3bcm are usually referred to as nanoplastics rather than microplastics. The ubiquity of microplastics of all sizes in surface water, groundwater and wastewater has raised the question if pollution of drinking water occurs and to date, few studies indeed described the presence of this new contaminant in tap and bottled water. Toxicity it is not yet known, they might cause local inflammations in the gut, but a transport into organs might occur. As a final problem in this field, microplastics in the environment are difficult to sample, to identify and standardized methods do not exist. For this reason, we have been involved in a research project finalized to the definition of a protocol strategy for sampling and analysis of microplastics in drinking waters, coming from deep water wells, in the networks of three large cities in the Northern part of Italy. The project is on going and presently two groups of deep water samples have been collected in the city of Milano and Brescia, before and after the treatment stages used for the urban network. Great attention has been paid to sampling and extraction steps as microplastic contamination, in this kind of samples, is expected to be very low and contamination during sampling might occur through air or materials. Analytical methods have been defined for the detection of main microplastic contamination, like PE/PP, PS, PA, PVC e PET residues > 1 \ub5m. Samples have been analysed first by a non-destructive approach using a Spotlight 200i microscope equipped with a \ub5ATR probe and coupled to an FT-IR spectrophotometer, followed by a mass spectrometric characterization of the polymers by a solid phase microextration (SPME) GC-MS of thermal decomposition products (TED) of microplastic residues. Results will be presented and critically discussed

On the formation of hot DQ white dwarfs

We present the first full evolutionary calculations aimed at exploring the origin of hot DQ white dwarfs. These calculations consistently cover the whole evolution from the born-again stage to the white dwarf cooling track. Our calculations provide strong support to the diffusive/convective-mixing picture for the formation of hot DQs. We find that the hot DQ stage is a short-lived stage and that the range of effective temperatures where hot DQ stars are found can be accounted for by different masses of residual helium and/or different initial stellar masses. In the frame of this scenario, a correlation between the effective temperature and the surface carbon abundance in DQs should be expected, with the largest carbon abundances expected in the hottest DQs. From our calculations, we suggest that most of the hot DQs could be the cooler descendants of some PG1159 stars characterized by He-rich envelopes markedly smaller than those predicted by the standard theory of stellar evolution. At least for one hot DQ, the high-gravity white dwarf SDSS J142625.70+575218.4, an evolutionary link between this star and the massive PG1159 star H1504+65 is plausible.Comment: 4 pages, 2 figures. To be published in The Astrophysical Journal Letter

Changes in drought tolerance of Pinus radiata in Chile associated with provenance and breeding generation

International audienceAbstractKey messageIn Chile, breeding radiata pine for growth has led to drifts in the degree of drought tolerance of the seedlings. Interior provenances gained a larger tolerance to drought after three breeding generations as shown by larger survival and root/shoot ratio under water shortage, while coastal provenance displayed an opposite trend.•Context Given that rainfall is predicted to decrease and to affect establishment and early survival of radiata pine (Pinus radiata D. Don) in Chile, there is a need to identify more drought tolerant genotypes at seedling stage.•Aims The aim of this study was to test whether provenances of P. radiata originating from interior or from coastal provenances, displayed different responses to short-term water shortage, and whether these responses differed from the first to the third breeding generation.•Methods Three generations of breeding families from two sites in Central Chile were compared. The seedlings were grown during 100 days and subjected to two watering regimes for 45 days. Survival, growth, and biomass allocation to roots and shoots were recorded.•Results The two provenances displayed different responses to drought. Biomass allocation to shoots and survival were significantly reduced by water shortage. The first generation seedlings from the coastal provenance displayed a larger survival rate when exposed to water shortage (i.e., 60 %); this rate decreased in the following breeding generations. On the contrary, the survival rate increased from the first to the third generation in the interior provenance.•Conclusions We observed an important local adaptation to water shortage in the interior provenance. This response may be due to the fact that parent tree populations of the interior provenance have successfully adapted to sites with periodic drought

Changing the paradigm in postherpetic neuralgia treatment: lidocaine 700 mg medicated plaster

OBJECTIVE: Chronic pain is currently considered a disease state with biopsychosocial consequences and a negative impact on patients' quality of life (QoL). Pain from postherpetic neuralgia (PHN) can persist for months or years and is a prototypical example of chronic pain. We analyzed PHN as a model of chronic pain. including its effects on QoL and clinical aspects. We explored treatment options, focusing on the topical treatment with lidocaine 700 mg medicated plaster (LMP) and how this impacts PHN management.MATERIALS AND METHODS: This article is a narrative review of published studies. Preclinical and clinical studies were retrieved from literature through a search performed in PubMed/MEDLINE.RESULTS: To choose the appropriate treatment for chronic pains, such as PHN, not only efficacy but also tolerability, manageability, practicality, and compliance are important factors. especially in the long term. It is also important to set treatment expectations with the patients as total suppression of pain may be unrealistic. and a balance needs to be found between pain control and the minimization of adverse events. In this respect, LMP may be the best currently available treatment: it is easy to use, has low systemic absorption and thus a low risk for pharmacological interactions. Therefore, treatments can be personalized, and concomitant medications can be added, if needed. Recent data from a real-world study support this view by showing that LMP has superior effectiveness in reducing pain and improving the QoL compared to other commonly used systemic treatments and confirming its good tolerability profile that is mainly characterized by localized skin reactions.CONCLUSIONS: LMP is one of the best currently available treatment options for PHN patients balancing good efficacy with an excellent tolerability profile and can therefore be considered for use as a first-line treatment for PHN

Development and validation of a GC–MS method for nicotine detection in Calliphora vomitoria (L.) (Diptera: Calliphoridae)

Entomotoxicology is the application of toxicological methods and analytical procedures on necrophagous insects feeding on decomposing tissues to detect drugs and other chemical components, and their mechanisms affecting insect development and morphology and modifying the methodology for estimation of minimum time since death. Nicotine is a readily available potent poison. Because of its criminal use, a gas chromatography-mass spectrometry (GC-MS) method for the detection of nicotine in Calliphora vomitoria L. (Diptera: Calliphoridae) was developed and validated. Furthermore, the effect of nicotine on the development, growth rate, and survival of this blowfly was studied. Larvae were reared on liver substrates homogeneously spiked with measured amounts of nicotine (2, 4, and 6 ng/mg) based on concentrations that are lethal to humans. The results demonstrated that (a) the GC-MS method can detect both nicotine and its metabolite cotinine in immature C. vomitoria; (b) the presence of nicotine in the aforementioned three concentrations in food substrates did not modify the developmental time of C. vomitoria; (c) during the pupation period, larvae exposed to nicotine died depending on the concentration of nicotine in the substrate; and (d) the resultant lengths of larvae and pupae exposed to 4 and 6 ng/mg concentrations of nicotine were significantly shorter than those of the control

Statistical analysis of correlations and intermittency of a turbulent rotating column in a magnetoplasma device

12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France)A detailed statistical analysis of density fluctuations in the cylindrical non-fusion device "Mistral" is performed. The experimental set-up is implemented in order to reach turbulent behavior in the rotating plasma column. Two different turbulent regimes are obtained corresponding to two selected sets of values for the anode potential and the biasing of the collecting plate. The first regime displays a slowly-rotating column characterized by the presence of a shear layer separating the plasma bulk from the scrape-off layer (SOL), the latter showing a strong intermittent behavior. The second regime corresponds to a weakly-rotating column in which coherence is lost in the plasma bulk and a standard diffusive process takes place in the SOL. These findings are supported by the calculation of the Hurst exponent of the turbulent signals using Wavelet-analysis techniques