Evaluation of group work in the Chemistry and Biotechnology laboratory: Case study

Trabalho apresentado em CISPEE 2018, 27-29 de junho de 2018, Aveiro, PortugalN/

Two-dimensional conical dispersion in ZrTe5 evidenced by optical spectroscopy

Zirconium pentatelluride was recently reported to be a 3D Dirac semimetal, with a single conical band, located at the center of the Brillouin zone. The cone's lack of protection by the lattice symmetry immediately sparked vast discussions about the size and topological/trivial nature of a possible gap opening. Here we report on a combined optical and transport study of ZrTe5, which reveals an alternative view of electronic bands in this material. We conclude that the dispersion is approximately linear only in the a-c plane, while remaining relatively flat and parabolic in the third direction (along the b axis). Therefore, the electronic states in ZrTe5 cannot be described using the model of 3D Dirac massless electrons, even when staying at energies well above the band gap 6 meV found in our experiments at low temperatures.Comment: Physical Review Letters 122, 217402 (2019). Corrected acknowledgment

Development of suported ionic liquids for the purification of antileukemic drugs

L-asparaginase (LA) is an antileukemic biopharmaceutical of current high-cost. LA is produced via fermentation and its purification usually comprises precipitation, liquid- liquid extraction and chromatography techniques [1]. This work aims to develop sustainable technologies to purify LA. Functionalized nanomaterials, namely supported ionic liquids (SILs), are used as cost-effective purification techniques for the target enzyme. Initially, the synthesis and modification of SILs was performed. Different SILs were obtained and used for the purification of LA. Commercial LA was used for the first purification tests, in order to understand the behavior of the enzyme in contact with the nanomaterial. Experimental conditions, such as pH, and material/LA ratio, contact time were optimized. LA activity was quantified by Nessler reaction [2]. The first results reveal a total adsorption of LA by the SILs with a recovered activity reaching 90% depending on the SILs functionalization/ treatment. The modified SILs are shown to be very promising nanomaterials for the purification of LA. The LA was easily attached to SILs by adsorption under mild conditions. SILs supports can be a real alternative for a single step immobilization/purification of LA.publishe

Synthesis, Bioavailability, and Cytotoxicity Studies

Funding Information: This work was supported by Portuguese funds from FCT/MCTES through the Associate Laboratory for Green Chemistry—LAQV (UIDB/50006/2020 and UIDP/50006/2020) and the project numbers PTDC/QUI-QOR/32406/2017 and PTDC/EAM-AMB/2023/2021. Ana R. Jesus and Ana Rita C. Duarte acknowledge the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Programme, under grant agreement No ERC-2016-CoG 725034. Publisher Copyright: © 2023 by the authors.Thyroid diseases affect a considerable portion of the population, with hypothyroidism being one of the most commonly reported thyroid diseases. Levothyroxine (T4) is clinically used to treat hypothyroidism and suppress thyroid stimulating hormone secretion in other thyroid diseases. In this work, an attempt to improve T4 solubility is made through the synthesis of ionic liquids (ILs) based on this drug. In this context, [Na][T4] was combined with choline [Ch]+ and 1-(2-hydroxyethyl)-3-methylimidazolium [C2OHMiM]+ cations in order to prepare the desired T4-ILs. All compounds were characterized by NMR, ATR-FTIR, elemental analysis, and DSC, aiming to check their chemical structure, purities, and thermal properties. The serum, water, and PBS solubilities of the T4-ILs were compared to [Na][T4], as well as the permeability assays. It is important to note an improved adsorption capacity, in which no significant cytotoxicity was observed against L929 cells. [C2OHMiM][T4] seems to be a good alternative to the commercial levothyroxine sodium salt with promising bioavailability.publishersversionpublishe

Binary Mutual Diffusion Coefficients of Isoniazid Aqueous Solutions at (298.15 and 310.15) K

Binary mutual diffusion coefficients measured by the Taylor dispersion method in two different laboratories (University of Naples, Federico II, Italy, and University of Coimbra, Portugal) are reported for aqueous solutions of isoniazid at concentrations from (0.000 to 0.100) mol·dm−3 and at two temperatures (298.15 and 310.15) K. The hydrodynamic radii for the isoniazid in aqueous solution are calculated from the experimental results. In addition, the Hartley equation and the experimental diffusion coefficients are used to estimate activity coefficients for aqueous isoniazid at both temperature

Information processing among high-performance managers

O propósito deste estudo foi avaliar o processamento da informação de 43 gestores empresariais de desempenho superior. No seu enquadramento teórico recorremos a três modelos: a Teoria dos Papéis Gerenciais de Henry Mintzberg, a Teoria do Processamento da Informação e o Modelo de Processo de Resposta ao Rorschach de John Exner. A ava-liação dos sujeitos recorreu ao método do Rorschach. Os resultados deste estudo mos-traram que esses gerentes são capazes de recolher dados, avaliá-los e estabelecer ran-kings de maneira adequada. Ao mesmo tempo, verifica-se que são capazes de ser objeti-vos e precisos na avaliação dos problemas. Este estilo de processamento de informação possibilita uma interpretação do mundo a partir de um modo de processamento ou de um estilo cognitivo, próprio e característico.The purpose of this study was to evaluate the information processing of 43 business managers with a professional superior performance. The theoretical framework consid-ers three models: the Theory of Managerial Roles of Henry Mintzberg, the Theory of In-formation Processing, and Process Model Response to Rorschach by John Exner. The participants have been evaluated by Rorschach method. The results show that these managers are able to collect data, evaluate them and establish rankings properly. At same time they are capable of being objective and accurate in the problems assessment. This information processing style permits an interpretation of the world around on basis of a very personal and characteristic processing way or cognitive style.Fundação para a Ciência e a Tecnologia (FCT), no âmbito do Fundo de Apoio à Comunidade Científica - Edição de Publicações Periódicas de Natureza Científica

Sustainable lysis of Bacillus subtilis biomass to recover the biopharmaceutical L-asparaginase

The first-line biopharmaceutical used to treat Acute lymphoblastic leukemia (ALL), Oncaspar, is based on the enzyme L-asparaginase (ASNase), and has annual sales of ca. USD $100 million. In addition to other sources, genetically modified Bacillus subtilis is regarded as one of the most promising hosts for the ASNase production. The Aliivibrio fischeri ASNase type II, which has anti-tumour activity due its higher specific affinity for L-asparagine, expressed in B. subtillis is located in the periplasm. Therefore, cell lysis is required for the ASNase recovery. Nevertheless, typical cell lysis approaches, e.g. chemical methods with surfactants lead to some biocompatibility concerns and the need of extra purification steps. To overcome this drawback, in this work, ultrasound sonication (USS) conditions were studied to develop a greener and more biocompatible method for ASNase recovery from B. subtilis cell lysis. The USS cell lysis was optimized regarding the amplitude of USS pulse, number of lysis cycles and mass of cells/volume of solvent ratio. The identification and quantification of ASNase and major impurities present in the cell extract after lysis were investigated by sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE) and size exclusion high-performance liquid chromatography (SE-HPLC). ASNase activity was determined by monitoring the hydrolysis of the substrate, L-asparagine. The results obtained show that the ideal conditions for B. subtilis cell lysis are an amplitude of USS pulse of 60%, 40 cycles of lysis and 10 mL of phosphatebuffered saline (PBS) per 1 g of cells. Overall, an optimized sustainable B. subtilis cell lysis method was developed, avoiding the use of surfactants and with low energy consumption.publishe

Supported ionic liquid materials for L-asparaginase bioconjugation

Since the average life expectancy is increasing, several fatal diseases usually related to aging, such as cancer, heart and neurological diseases have become predominant. Biopharmaceuticals, namely nucleic-acid-based products, antibodies, recombinant proteins and enzymes are fundamental to overcome these age-related diseases. Actually, the gold standard enzyme for the treatment of acute chronic lymphoblastic leukemia (ALL) is L-asparaginase (ASNase). Hence, the reusability of this high-priced drug enables the cost reduction of treatments, which allows its routinely use by a widespread population. In this work, functionalized nanomaterials, namely supported ionic liquid materials (SILs) based on silica, formerly described in the literature for the separation of natural compounds from vegetable biomass, were studied as a cost effective support for ASNase immobilization and reuse. Commercial ASNase was used for preliminary tests. Several experimental immobilization conditions, such as pH, contact time, ASNase concentration and SILs recyclability were assessed and optimized, regarding the immobilized ASNase activity, assessed by Nessler reaction, which quantifies the amount of ammonium released after the enzymatic reaction with L-asparagine and immobilization yield. In fact, ASNase immobilization onto the SILs was successfully achieved with an immobilized ASNase activity ranging from 0.6 to 0.9 U of enzyme per mg of SILs under the optimum immobilization conditions. Moreover, all SILs allowed 5 cycles of reaction, while keeping more than 75% of initial ASNase activity. Through the envisioned immobilization strategy, process costs will be considerably reduced, which can lead to a wider use of ASNase in diverse fields of application.publishe

Recent strategies and applications for l-asparaginase confinement

l-asparaginase (ASNase, EC 3.5.1.1) is an aminohydrolase enzyme with important uses in the therapeutic/pharmaceutical and food industries. Its main applications are as an anticancer drug, mostly for acute lymphoblastic leukaemia (ALL) treatment, and in acrylamide reduction when starch-rich foods are cooked at temperatures above 100 °C. Its use as a biosensor for asparagine in both industries has also been reported. However, there are certain challenges associated with ASNase applications. Depending on the ASNase source, the major challenges of its pharmaceutical application are the hypersensitivity reactions that it causes in ALL patients and its short half-life and fast plasma clearance in the blood system by native proteases. In addition, ASNase is generally unstable and it is a thermolabile enzyme, which also hinders its application in the food sector. These drawbacks have been overcome by the ASNase confinement in different (nano)materials through distinct techniques, such as physical adsorption, covalent attachment and entrapment. Overall, this review describes the most recent strategies reported for ASNase confinement in numerous (nano)materials, highlighting its improved properties, especially specificity, half-life enhancement and thermal and operational stability improvement, allowing its reuse, increased proteolysis resistance and immunogenicity elimination. The most recent applications of confined ASNase in nanomaterials are reviewed for the first time, simultaneously providing prospects in the described fields of application.publishe