Applications of fluorescent sensor based on 1H-pyrazolo[3,4-b]quinoline in analytical chemistry

Fluorescent dye 2-[(2-Hydroxyethyl)-(1,3-diphenyl-1H-pyrazolo[3,4-b]quinolin-6-ylmethyl)-amino]ethanol (LL1) was examined for its efficiency in the detection of small inorganic cations (lithium, sodium, barium, calcium, magnesium, cadmium, lead and zinc). The dye was synthesized in the laboratory and investigated by means of both, steady-state and time-resolved fluorescence techniques. This compound acts as a fluorescent sensor suitable for detection of small inorganic cations (lithium, sodium, barium, calcium, magnesium, cadmium, lead and zinc) in strongly polar solvent (acetonitrile). An electron transfer from the electro-donative part (receptor) of the molecule to the acceptor part (fluorophore) is thought to be the main mechanism that underlies functionality of the compound as a sensor. This process can be retarded upon complexation of the receptor moiety by inorganic cations. Relatively high sensitivity but poor selectivity of the aminoalcohol thatcontains indicator towards the two-valued cations was observed. However, upon addition of some amounts of water the selectivity of this sensor has been enhanced (especially towards lead cation). The preliminary results in analytical application of the sensor are discussed

Chemical Enrichment in the Carbon-enhanced Damped Lyman α\alpha System

We show that the recently observed elemental abundance pattern of the carbon-rich metal-poor Damped Lyman $\alpha$ (DLA) system is in excellent agreement with the nucleosynthesis yields of faint core-collapse supernovae of primordial stars. The observed abundance pattern is not consistent with the nucleosynthesis yields of pair-instability supernovae. The DLA abundance pattern is very similar to that of carbon-rich extremely metal-poor (EMP) stars, and the contributions from low-mass stars and/or binary effects should be very small in DLAs. This suggests that chemical enrichment by the first stars in the first galaxies is driven by core-collapse supernovae from $\sim 20-50 M_\odot$ stars, and also supports the supernova scenario as the enrichment source of EMP stars in the Milky Way Galaxy.Comment: 5 pages, 1 figure, accepted to the Astrophysical Journal, Lette

Effects of selective harvesting on traffic pattern and soil compaction in a subtropical forest in Guarani, Misiones, Argentine = Efeitos da exploração seletiva de florestas neotropicais em padrões de tráfego e na compactação do solo em Guarani, Misiones, Argentina

A colheita de madeira na floresta tropical produz impactos muito importantes, especialmente na compactação do solo. Neste trabalho foram comparados os efeitos de dois sistemas de colheita seletiva na compactação do solo, em uma floresta neotropical na reserva Guarani, em Misiones, Argentina. Os métodos de colheita foram: o comercial (CH), empregado pelos empreiteiros da região e a colheita de baixo impacto (RIL), com seleção das árvores a serem cortadas e com planejamento para a locação das vias de arraste e dos pátios, em função das condições do terreno. A área das vias de arraste e a intensidade de tráfego, em relação à compactação do solo, foram comparadas com o volume de árvores colhidas e as condições do terreno. Detectou-se que o tratamento RIL concentra o volume de toras e o peso das toras, e reduz a carga total sobre o solo, e a intensidade de tráfego, principalmente nos caminhos primários. O aumento da intensidade de tráfego resultou em maior compactação do solo e em maior profundidade. O método de colheita RIL evita o aumento da compactação do solo, pela redução na carga total aplicada sobre o solo.Harvesting tropical forests produce important impacts, especially in soil compaction. Effects of selective harvesting methods on soil compaction were compared in a natural subtropical forest in the Guarani preservation area, Misiones state, Argentine. An ordinary commercial harvesting method (CH) used by the logging contractors in the region and reduced impact logging method (RIL) with selection of harvestable trees and limitation of the skidding trials and landings were applied with reference to terrain condition. Area of skid trails; intensities of traffic related to extent of soil compaction were compared with volume of harvested trees and terrain condition. It was found that the RIL treatment concentrates the logs volume and logs weight, with a diminution of the total load over the soil, and the traffic intensity, especially on primary roads. The increase of the traffic intensities resulted in higher soil compaction at deepest depth. Planned logging operations through the RIL method, avoid significant soil compaction through the reduction of the total load over the soil.EEA MontecarloFil: Mac Donagh, Patricio. Universidad Nacional de Misiones. Facultad de Ciencias Forestales; ArgentinaFil: Rivero, Liliana. Universidad Nacional de Misiones. Facultad de Ciencias Forestales; ArgentinaFil: Garibaldi, Juan. Universidad Nacional de Misiones. Facultad de Ciencias Forestales; ArgentinaFil: Alvez, Mario. Universidad Nacional de Misiones. Facultad de Ciencias Forestales; ArgentinaFil: Cortez, Pablo. Universidad Nacional de Misiones. Facultad de Ciencias Forestales; ArgentinaFil: Marek, Marcelo. Universidad Nacional de Misiones. Facultad de Ciencias Forestales; ArgentinaFil: Erbetta, Diego. Universidad Nacional de Misiones. Facultad de Ciencias Forestales; ArgentinaFil: Fernandez, Roberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Montecarlo; ArgentinaFil: Pahr, Norberto Manuel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Montecarlo; ArgentinaFil: Toma, Takeshi. Forestry and Forest Products Research Institute; Japó

A New Fluorescent Sensor Based on 1H-pyrazolo[3,4-b]quinoline Skeleton. Part 2

A novel fluorescent dye bis-(pyridin-2-yl-methyl)-(1,3,4-triphenyl-1H-pyrazolo[3,4-b]quinolin-6-ylmethyl)-amine (P1) has been synthesized and investigated by means of steady state and time-resolved fluorescence techniques. This compound acts as sensor for fluorescence detection of small inorganic cations (lithium, sodium, barium, magnesium, calcium, and zinc) in highly polar solvents such as acetonitrile. The mechanism which allows application of this compound as sensor is an electron transfer from the electron-donative part of molecule (amine) to the acceptor part (pyrazoloquinoline derivative), which is retarded upon complexation of the electro-donative part by inorganic cations. The binding constants are strongly dependent on the charge density of the analyzed cations. The 2/1 complexes of P1 with Zn++ and Mg++ cations posses large binding constants. Moreover, in the presence of these cations a significant bathochromic shift of fluorescence is observed. The most probable explanation of such behaviour is the formation of intramolecular excimer. This is partially supported by the quantum chemical calculations

A multi-country test of brief reappraisal interventions on emotions during the COVID-19 pandemic.

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about a situation. Participants from 87 countries and regions (n = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vesus both control conditions) consistently reduced negative emotions and increased positive emotions across different measures. Reconstrual and repurposing interventions had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world