Distribution models for nitrophenols in a liquid-liquid system

The formation of nitrophenols by-products is still of major concern for the economics and environmental impact of the industrial process of benzene (Bz) nitration to mononitrobenzene (MNB) with mixed acid (sulphuric and nitric acids). The knowledge of nitrophenol (NP) distribution ratios in the liquid-liquid mixture (Dj,j={NP}) is desirable for process optimization and for understanding the reaction mechanisms behind nitrophenols formation. In this study, a data-driven approach was implemented to provide prediction models for Dj of 2,4-dinitrophenol (DNP) and of 2,4,6-trinitrophenol (TNP) in a biphasic liquid system with a composition representative of the industrial processes. In the first step, screening tests were performed to identify the main variables influencing the experimental equilibrium weight fractions of nitrophenols in the aqueous phase wj,eA. Subsequently two independent data sets were built for development and external validation of prediction multivariate linear regression (MLR) models, at 30°C. The fitting results (R2 and Rad2⩾0.90) and the prediction results (Rpred,DNP2=0.931,Rpred,TNP2=0.908) confirmed the quality of the wj,eA models. Statistical significant predictive MLR models were also developed for Dj (which is related with wj,eA), at 30°C, with DNP evidencing a higher affinity for the organic phase (i.e. DDNP≈2DTNP).publishe

Synthesis and characterization of PbS quantum dots embedded in oxide glass

The fusion method was used to produce PbS quantum dots (QDs) embedded in S-doped glass matrix (SiO2-Na2CO3-Al2O3-PbO2-B2O3:S). Measurements of optical absorption (OA), photoluminescence (PL) and atomic force microscopy (AFM) have been carried out in order to characterize the produced QDs. A strong red-shift observed in the optical features with an increase of the annealing time indicates an increase in QD-size. The QD sizes predicted by k.p theoretical results were confirmed by AFM observation

The RabGEF ALS2 is a hypoxia inducible target associated with the acquisition of aggressive traits in tumor cells

Indexación ScopusTumor hypoxia and the hypoxia inducible factor-1, HIF-1, play critical roles in cancer progression and metastasis. We previously showed that hypoxia activates the endosomal GTPase Rab5, leading to tumor cell migration and invasion, and that these events do not involve changes in Rab protein expression, suggesting the participation of intermediate activators. Here, we identified ALS2, a guanine nucleotide exchange factor that is upregulated in cancer, as responsible for increased Rab5-GTP loading, cell migration and metastasis in hypoxia. Specifically, hypoxia augmented ALS2 mRNA and protein levels, and these events involved HIF-1α-dependent transcription, as shown by RNAi, pharmacological inhibition, chromatin immunoprecipitation and bioinformatics analyses, which identified a functional HIF-1α-binding site in the proximal promoter region of ALS2. Moreover, ALS2 and Rab5 activity were elevated both in a model of endogenous HIF-1α stabilization (renal cell carcinoma) and by following expression of stable non-hydroxylatable HIF-1α. Strikingly, ALS2 upregulation in hypoxia was required for Rab5 activation, tumor cell migration and invasion, as well as experimental metastasis in C57BL/6 mice. Finally, immunohistochemical analyses in patient biopsies with renal cell carcinoma showed that elevated HIF-1α correlates with increased ALS2 expression. Hence, this study identifies ALS2 as a novel hypoxia-inducible gene associated with tumor progression and metastasis. © 2020, The Author(s).https://www-nature-com.recursosbiblioteca.unab.cl/articles/s41598-020-79270-

Avaliação nutricional do resíduo desidratado de cervejaria para coelhos em crescimento

RESUMO Foi conduzido um ensaio de digestibilidade para determinar o valor nutritivo do resíduo desidratado de cervejaria (RDC) e outro para verificar o desempenho de coelhos em crescimento alimentados com rações contendo diferentes níveis de RDC e a viabilidade econômica da utilização do RDC. No ensaio de digestibilidade, foram utilizados 20 coelhos, de ambos os sexos, da raça Nova Zelândia Branco, com idade média de 45 dias, distribuídos em delineamento experimental inteiramente ao acaso, com dois tratamentos, sendo uma dieta referência e outra dieta teste, na qual o RDC substituiu a ração referência em nível de 30%. Os coeficientes de digestibilidade aparente (CDA) da matéria seca (MS), da energia bruta (EB), da proteína bruta (PB) do RDC foram de 49,97%, 49,34%, e 71,06%, respectivamente, com valores de energia digestível (ED) e proteína digestível (PD) do RDC, com base na matéria seca, de 2330,60kcal/kg e 15,75%. No experimento de desempenho, foram avaliadas rações com níveis de inclusão de RDC de 0%, 5%, 10%, 15%, 20% e 25%. Foram utilizados 120 coelhos da raça Nova Zelândia Branco, 60 machos e 60 fêmeas, com 32 dias de idade, em delineamento experimental inteiramente ao acaso, com seis tratamentos e 10 repetições, sendo a unidade experimental constituída por dois animais. Não foram observadas diferenças no desempenho dos coelhos alimentados com ração contendo níveis crescentes de RDC, exceto para a conversão alimentar aos 70 dias, que apresentou efeito quadrático no período dos 32 aos 70 dias de idade, com a pior conversão alimentar ao nível de 16,95% de RDC. No entanto, houve redução linear nos custos com alimentação, por quilo de ganho de peso dos animais. Conclui-se que o resíduo desidratado de cervejaria apresenta CDA equivalente aos ingredientes convencionais, podendo ser incluído até o nível máximo estudado de 25% nas rações de coelhos em crescimento, sem prejudicar o desempenho