Synthesis and characterization of dicarboxymethyl cellulose

Associate Laboratory for Green Chemistry-LAQV which is financed by national funds from FCT/MCTES (UID/QUI/50006/2019). FCT, Portugal (ROTEIRO/0031/2013–PINFRA/22161/2016, co-financed by FEDER through COMPETE 2020, POCI, and PORL and FCT through PIDDAC).Synthesis of dicarboxymethyl cellulose (DCMC) under heterogeneous conditions was examined. Cellulose was etherified using sodium bromomalonate in isopropanol/water in the presence of NaOH. The reaction was performed with five different NaOH concentrations (5–30 w/v %) and the products were characterized by anion-exchange high-performance liquid chromatography (AE-HPLC), inductively coupled plasma atomic emission- (ICP-AES), Fourier transform infrared- (FTIR), and nuclear magnetic resonance (1D-/2D-NMR) spectroscopy. Adjusting the amount of NaOH resulted in increasing functionalization of the cellulose achieving an average degree of substitution (DS) between 0.05 and 0.51. Both ICP-AES and AE-HPLC gave comparable DS values. NMR spectroscopic analysis showed that etherification occurred preferably at O-6 and, to a certain extent, at the secondary positions depending on the reaction conditions. Graphic abstract: [Figure not available: see fulltext.].authorsversionpublishe

The variability behavior of CoRoT M-giant Stars

For 6 years the Convection, Rotation, and Planetary Transits (CoRoT) space mission has acquired photometric data from more than one hundred thousand point sources towards and directly opposite from the inner and outer regions of the Galaxy. The high temporal resolution of the CoRoT data combined with the wide time span of the observations has enabled the study of short and long time variations in unprecedented detail. From the initial sample of 2534 stars classified as M-giants in the CoRoT databasis, we selected 1428 targets that exhibit well defined variability, using visual inspection. The variability period and amplitude of C1 stars (stars having Teff < 4200 K) were computed using Lomb-Scargle and harmonic fit methods. The trends found in the V-I vs J-K color-color diagram are in agreement with standard empirical calibrations for M-giants. The sources located towards the inner regions of the Galaxy are distributed throughout the diagram while the majority of the stars towards the outer regions of the Galaxy are spread between the calibrations of M-giants and the predicted position for Carbon stars. The stars classified as supergiants follow a different sequence from the one found for giant stars. We also performed a KS test of the period and amplitude of stars towards the inner and outer regions of the Galaxy. We obtained a low probability that the two samples come from the same parent distribution. The observed behavior of the period-amplitude and period-Teff diagrams are, in general, in agreement with those found for Kepler sources and ground based photometry, with pulsation being the dominant cause responsible for the observed modulation. We also conclude that short-time variations on M-Giant stars do not exist orare very rare and the few cases we found are possibly related to biases or background stars.Comment: 11 pages, 6 figure

Cactus Cladodes Opuntia or Nopalea and By-Product of Low Nutritional Value as Solutions to Forage Shortages in Semiarid Areas

Simple Summary In the different livestock production systems, forage is the main feed resource. However, the availability and quality of the forage fluctuate throughout the year due to variable environmental conditions, such as temperature, humidity, location, or lack of rainfall. In semiarid regions, this fact is even more critical. The option for forage plants adapted to the semiarid climate, such as cactus cladodes, becomes indispensable for the sustainability of the systems. Nonetheless, it is necessary to combine the cactus with high-fiber-content feeds (silage, hay, and agroindustry residues, among others) to increase fiber contents in the diet to promote ideal rumen conditions. Based on the knowledge that cactus cladodes (Opuntia spp. and Nopalea spp.) are one of the most viable crops in semiarid regions, the association with a by-product rich in NDF proves to be a more feasible alternative in terms of price and availability, with the producer making the final decision. We aimed to evaluate the effect of the cactus cladodes Nopalea cochenillifera (L). Salm-Dyck. (NUB) and cactus cladodes Opuntia stricta (Haw.) Haw. (OUB), both combined with sugarcane bagasse (SB) plus urea, Tifton hay (TH), corn silage (CS), and sorghum silage (SS) plus urea on nutrient intake and digestibility, ruminal dynamics, and parameters. Five male sheep, fistulated in the rumen, were assigned in a 5 x 5 Latin square design. The NUB provided a higher intake of dry matter (DM) and any nutrients than SS. TH provided larger pools of DM and iNDF. The OUB and CS provided a higher DM degradation. CS provided a higher NDF degradation rate. OUB provided a lower ruminal pH. Depending on the collection time, the lowest pH value was estimated at 3.79 h after the morning feeding. There was an interaction between treatments and collection time on VFA concentrations. Due to the high degradation rate, greater energy intake, less change in rumen pH, greater volatile fatty acid production, and feasibility, we recommend using cactus associated with sugarcane bagasse plus urea in sheep diets

Uso de indutores de brotação em pessegueiros "Eragil".

O pessegueiro é uma frutífera de clima temperado de grande importância socioeconômica no Rio Grande do Sul. As cultivares utilizadas apresentam índices de brotação satisfatórios nas condições climáticas locais

Contribuição do Projeto PIBID na melhora nos índices de aprovação dos alunos na disciplina de Química no Colégio Professor Pedro Carli

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Flutuação populacional de pragas e predadores em citros

This study was carried out in a 5.000 m2 area at Piracicaba, SP, Brazil, to determine the behavior of the pest and predator insects in citrus. A portable vacuum collector AS-ESALQ modal as used. Weekly, samples were taken at rondom from the top of ten plants, 20 times per plant. Two species - Aleurothrixus floccosus (Maskell 1896) and Toxoptera citricidus (Kirk 1907) - were the only Coleoptera pests found. They occurred through all the year, having higher frequencies in April and November. The predators from file Coleoptera were: Cycloneda sanguinea (Linné 1763). Nephaspis sp., Scymnus sp, and Stethorus sp. Three species of Neuroptera were found: Chrysopa sp., Megalomus sp., and Hemerobius sp., that have population peaks in January, August and December. One Diptera species was found as of importance: Micrempis sp., which presented four peaks, in the months January, April, August and October.Experimento efetuado numa área de citros, de 5.000 m2, em Piracicaba, SP, para determinar o comportamento dos insetos-pragas e insetos-predadores, em citros. Foi usado um coletor de sucção, portátil, modelo AS-ESALQ. Semanalmente, em 1977, as coletas foram feitas ao acaso, de dez plantas, por sucção do aparelho, em número de 20, ao redor da copa de cada árvore. Duas espécies revelaram-se pragas: Aleurothrixus floccosus (Maskell 1896) e Toxoptera citricidus (Kirk 1907). Foram as únicas pragas da ordem Homoptera. Ambos ocorreram durante o ano inteiro, apresentando dois picos populacionais: um, em abril, e outro, em novembro. Entre os coleópteros, houve quatro espécies de predadores: Cycloneda sanguinea (Linné 1763), Nephaspis sp, Scymnus sp., e Stethorus sp.; e entre os neurópteros, as três espécies: Chrysopa sp., Megalomus sp. e Hemerobius sp., que apresentaram picos populacionais em janeiro, agosto e dezembro. Entre os dípteros, foi observada apenas uma espécie de notável importância, e que apresentou quatro picos - a saber, em janeiro, abril, agosto e outubro -: É a Micrempis sp

Efeito do volume do tanque-rede na produtividade de tambaqui (Colossoma macropomum) durante a recria.

O objetivo desta nota foi avaliar o efeito do volume do tanque-rede na produtividade de juvenis de tambaqui durante a recria