Computational Study on the Inhibition Mechanisms of the Ziegler-Natta Catalyst in the Propylene Polymerization Process: Part 1 Effects of Acetylene and Methylacetylene.

Acetylene and methylacetylene are impurities commonly found in the raw materials used for the production of polymers such as polypropylene and polyethylene. Experimental evidence indicates that both acetylene and methylacetylene can decrease the productivity of the Ziegler-Natta catalyst and alter the properties of the resulting polymer. However, there is still a lack of understanding regarding the mechanisms through which these substances affect this process. Therefore, elucidating these mechanisms is crucial to develop effective solutions to this problem. In this study, the inhibition mechanisms of the Ziegler-Natta catalyst by acetylene and methylacetylene are presented and compared with the incorporation of the first propylene monomer (chain initiation) to elucidate experimental effects. The Density Functional Theory (DFT) method was used, along with the B3LYP-D3 functional and the 6-311++G(d,p) basis set. The recorded adsorption energies were -11.10, -13.99, and -0.31 kcal mol-1, while the activation energies were 1.53, 2.83, and 28.36 kcal mol-1 for acetylene, methylacetylene, and propylene, respectively. The determined rate constants were 4.68 × 1011, 5.29 × 1011, and 2.3 × 10-8 M-1 s-1 for acetylene, methylacetylene, and propylene, respectively. Based on these values, it is concluded that inhibition reactions are more feasible than propylene insertion only if an ethylene molecule has not been previously adsorbed, as such an event reinforces propylene adsorption.

NMR analysis, cytotoxic activity and theoretical study of a complex between SRPIN340 and p-sulfonic acid calix[6]arene.

Aim: This study aimed to enhance the aqueous dissolution of SRPK inhibitor N-(2-(piperidin-1-yl)-5-(trifluoromethyl)phenyl)isonicotinamide (SRPIN340).Materials & Methods: A complex with p-sulfonic calix[6]arene (Host) and SRPIN340 (Guest) was prepared, studied via 1H nuclear magnetic resonance (NMR) and theoretical calculations and biologically evaluated on cancer cell lines.Results & conclusion: The 1:1 host (H)/guest (G) complex significantly enhanced the aqueous dissolution of SRPIN340, achieving 64.8% water solubility as determined by 1H NMR quantification analysis. The H/G complex reduced cell viability by 75% for HL60, ∼50% for Nalm6 and Jurkat, and ∼30% for B16F10 cells. It exhibited greater cytotoxicity than free SRPIN340 against Jurkat and B16F10 cells. Theoretical studies indicated hydrogen bond stabilization of the complex, suggesting broader applicability of SRPIN340 across diverse biological systems.

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Removal of phenazopyridine from water, synthetic urine, and real sample by adsorption using graphene oxide: A DFT theoretical/experimental approach.

Herein, graphene oxide was used as the highly efficient phenazopyridine adsorbent from aqueous medium, synthetic, and human urine. The nanoadsorbent was characterized by different instrumental techniques. The adsorption capacity (1253.17 mg g-1) was reached at pH 5.0, using an adsorbent dosage of 0.125 g L-1 at 298 K. The Sips and Langmuir described the equilibrium data well. At the same time, the pseudo-second order was more suitable for fitting the kinetic data. Thermodynamic parameters revealed the exothermic nature of adsorption with an increase in randomness at the solid-liquid interface. The magnitude of the enthalpy variation value indicates that the process involves the physisorption phenomenon. At the same time, ab initio molecular dynamics data corroborated with the thermodynamic results, indicating that adsorbent and adsorbate establish hydrogen bonds through the amine groups (adsorbate) and hydroxyl groups on the adsorbent surface (weak interactions). Electrostatic interactions are also involved. Additionally, the adsorption assays conducted in simulated medium and human urine showed the excellent performance of adsorbent material to remove the drug in real concentrations excreted by the kidneys (removal values higher than 60%).

CO2 capture and a route to transform it in formic acid: a theoretical approach.

New organic frameworks (COFs) employing two coronene molecules forced to adopt a parallel conformation thus forming a molecular reactor are proposed. These COFs exhibit different distances between the coronene units, thus creating diverse electronic environments. The simulation of the trapping of CO2 and H2 molecules in the reactor hollow having distinct anchor fragments yields in the two cases formic acid. The analysis of the reaction profile allowed us to propose a thermodynamically favored process. The nature of the frontier molecular orbitals in the involved processes is also discussed. Reaction profile of CO2 and H2 process to yield formic acid.

Phenoxy- and Phenylamino-Heterocyclic Quinones: Synthesis and Preliminary Anti-Pancreatic Cancer Activity.

The successful application of fragment-based drug discovery strategy for the efficient synthesis of phenoxy- or phenylamino-2-phenyl-benzofuran, -benzoxazole and -benzothiazole quinones is described. Interestingly, in the final step of the synthesis of the target compounds, unusual results were observed on the regiochemistry of the reaction of bromoquinones with phenol and aniline. A theoretical study was carried out for better understanding the factors that control the regiochemistry of these reactions. The substituted heterocyclic quinones were evaluated in vitro to determine their cytotoxicity by the MTT method in three pancreatic cancer cell lines (MIA-PaCa-2, BxPC-3, and AsPC-1). Phenoxy benzothiazole quinone 26a showed potent cytotoxic activity against BxPC-3 cell lines, while phenylamino benzoxazole quinone 20 was the most potent on MIA-PaCa-2 cells. Finally, electrochemical properties of these quinones were determined to correlate with a potential mechanism of action. All these results, indicate that the phenoxy quinone fragment led to compounds with increased activity against pancreatic cancer cells.

Aconselhamento Psicológico como Construção Social / Counselling Psychology as Social Construction / Asesoramiento Psicológico como Construcción Social

Resumo Este trabalho tem como objetivo apresentar as contribuições da perspectiva construcionista social para se pensar o campo do Aconselhamento Psicológico. Os principais pressupostos construcionistas sociais na área da psicologia social e da terapia familiar são colocados em diálogo com as definições contemporâneas de Aconselhamento Psicológico a partir da crise pós-moderna vivida nessa disciplina. Considerando-se a inexistência de estudos nacionais no tema, as teorias construcionistas sociais utilizadas no campo do aconselhamento em outros países são brevemente apresentadas e as produções internacionais da área cujos autores assumem o uso de aconselhamento em uma perspectiva construcionista social são discutidas. Esses aspectos servem de base para o tecer de algumas considerações críticas sobre o uso dessa perspectiva no campo do Aconselhamento e para proposição do Aconselhamento Psicológico como uma prática de produção de sentidos sobre um plano de ação de reconexão de pessoas, redes e instituições, com a inclusão de múltiplos protagonistas e com o profissional como facilitador desse processo conectivo, como parceiro na redescrição do sofrimento individual em termos de agenda de transformação social....(AU)

Abstract This paper aims to present the contributions of the social constructionist perspective to the understanding of Counselling Psychology. The main social constructivist assumptions in the field of social psychology and family therapy are put into dialogue with the contemporary definitions of Counselling Psychology, in view of the postmodern crisis experienced by this discipline. Considering the lack of Brazil-wide studies on the subject, we briefly present some social constructionist theories used in the field of counselling in other countries. Additionally, we discuss international studies whose authors address the use of counselling from a social constructionist perspective. These aspects provide the basis for critical considerations on the use of this perspective in the field of Counselling. They also enable us to propose Counselling Psychology as a way to produce meaning in an action plan for reconnecting people, networks and institutions, with the inclusion of multiple protagonists and professionals acting as facilitators of this connective process and as partners in the redescription of individual suffering in a social transformation agenda....(AU)

Resumen Este trabajo tiene como objetivo presentar las contribuciones de la perspectiva construccionista social para pensar el campo del Asesoramiento Psicológico. Los principales supuestos del construccionismo social en el área de la psicología social y de la terapia familiar se ponen en diálogo con las definiciones contemporáneas de Asesoramiento Psicológico a partir de la crisis posmoderna vivida en esa disciplina. Al considerar la inexistencia de estudios nacionales en el tema, las teorías construccionistas sociales utilizadas en el campo del asesoramiento en otros países son brevemente presentadas y las producciones internacionales del área cuyos autores asumen el uso de asesoramiento en una perspectiva construccionista social son discutidas. Estos aspectos sirven de base para el tejer de algunas consideraciones críticas sobre el uso de esa perspectiva en el campo del asesoramiento y para la proposición del asesoramiento psicológico como una práctica de producción de sentidos sobre un plan de acción de reconexión de personas, redes e instituciones, inclusión de múltiples protagonistas y con el profesional como facilitador de ese proceso conectivo, como aliado en la re descripción del sufrimiento individual en términos de agenda de transformación social....(AU)

99Tc NMR as a promising technique for structural investigation of biomolecules: theoretical studies on the solvent and thermal effects of phenylbenzothiazole complex.

The phenylbenzothiazole compounds show antitumor properties and are highly selective. In this paper, the (99)Tc chemical shifts based on the ((99m)Tc)(CO)3 (NNO) complex conjugated to the antitumor agent 2-(4'-aminophenyl)benzothiazole are reported. Thermal and solvent effects were studied computationally by quantum-chemical methods, using the density functional theory (DFT) (DFT level BPW91/aug-cc-pVTZ for the Tc and BPW91/IGLO-II for the other atoms) to compute the NMR parameters for the complex. We have calculated the (99)Tc NMR chemical shifts of the complex in gas phase and solution using different solvation models (polarizable continuum model and explicit solvation). To evaluate the thermal effect, molecular dynamics simulations were carried, using the atom-centered density matrix propagation method at the DFT level (BP86/LanL2dz). The results highlight that the (99)Tc NMR spectroscopy can be a promising technique for structural investigation of biomolecules, at the molecular level, in different environments.