Equipamento de baixo custo para extração em fase sólida em amostras aquosas de grande volume utilizando pressão positiva de N

Extraction/concentration is a crucial step for the analysis of organic compounds at trace level concentrations and dispersed in complex matrices. Solid-phase extraction (SPE) is one of the techniques used for this purpose. In this work, a low cost apparatus for SPE was developed that uses nitrogen under positive pressure and ensures the maintenance of the sample flow, while also allows the simultaneous extraction of different samples without cross-contamination and sample contact with plastic materials. For the system set up, easily accessible materials were used such as hypodermic needles, stainless steel tubes, rubber stoppers, and 3-way valves from serum delivery apparatus

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Physicochemical Properties and Dissolution Studies of Dexamethasone Acetate-β-Cyclodextrin Inclusion Complexes Produced by Different Methods

Inclusion complexes between dexamethasone acetate (DMA), a poorly water soluble drug, and β-cyclodextrin (βCD) were obtained to improve the solubility and dissolution rate of this drug. Phase-solubility profile indicated that the solubility of DMA was significantly increased in the presence of βCD (33-fold) and was classified as AL-type, indicating the 1:1 stoichiometric inclusion complexes. Solid complexes prepared by different methods (kneading, coevaporation, freeze drying) and physical mixture were characterized by differential scanning calorimetry, thermogravimetry, infrared absorption and optical microscopy. Preparation methods influenced the physicochemical properties of the products. The dissolution profiles of solid complexes were determined and compared with those DMA alone and their physical mixture, in three different mediums: simulated gastric fluid (pH 1.2), simulated intestinal fluid (pH 7.4) and distilled water. The dissolution studies showed that in all mediums DMA presented an incomplete dissolution even in four hours. In contrast, the complexes formed presented a higher dissolution rate in simulated gastric fluid (SGF pH 1.2), which indicate that these have different ionization characteristics. According to the results, the freeze–dried and kneaded products exhibited higher dissolution rates than the drug alone, in all the mediums

Jacaratia corumbensis O. Kuntze a new vegetable source for milk-clotting enzymes

The partial characterization and purification of milk clotting enzyme obtained from the (root latex) of Jacaratia corumbensis O. kuntze was studied, by fractional precipitation with ammonium sulphate and ion exchange chromatography. The ammonium sulphate precipitate showed five fractions (AS1- 0-20%; AS2 - 20-40%; AS3 - 40-60%; AS4 - 60-80%; AS5 - 80-100%) and among the fractions obtained, the 40-60% fraction (AS3) showed the highest milk clotting activity with a purification factor of 1.2 fold in relation to the crude extract. This fraction when applied on Mono Q column yielded two protein peaks (p1 and p2), but p1 pool showed the best milk-clotting activity. The optimal pH for the crude and partially purified extract was 6.5 and 7.0, respectively. The maximum milk-clotting activity was at 55ºC for the both crude and partially purified extracts. The enzyme was inhibited by iodoacetic acid which suggested that this enzyme was a cysteine protease, with molecular weight of 33 kDa.<br>A enzima coagulante de leite obtida de látex de raiz de Jacaratia corumbensis O. kuntze foi caracterizada parcialmente e purificada, por precipitação fracionária com sulfato de amônio e cromatografia de troca de íon. Foram utilizadas cinco frações de sulfato de amônio (AS1 - 0-20%; AS2 - 20-40%; AS3 - 40-60%; AS4 - 60-80%; AS5 - 80-100%), a fração 40-60% (AS3) mostrou alta atividade coagulante com um fator de purificação de 1,2 vezes em relação ao extrato bruto. Esta fração foi aplicada em coluna Mono Q obtendo dois picos de proteína (p1 e p2), o p1 mostrou melhor atividade coagulante. O pH ótimo para o extrato bruto e parcialmente purificado foi 6,5 e 7,0, respectivamente. A atividade coagulante foi atingida a 55ºC para ambos os extratos, bruto e parcialmente purificado. A enzima foi inibida por ácido iodoacético que sugere que esta enzima é uma cisteína protease, com peso molecular de 33 kDa