Navegando por Data de Publicação, começando com "2021-07-26"

Filtrar resultados por ano ou mês

Agora exibindo 1 - 2 de 2

Propriedades citotóxicas de complexos de Cu(I)-Trifenilfosfina com ligantes aciltioureias ou naftoquinonas
(Universidade Federal de São Carlos, 2021-07-26) Leite, Celisnolia Morais; Batista, Alzir Azevedo; https://lattes.cnpq.br/6469642481998660; https://lattes.cnpq.br/9638881050186865
In this work, the synthesis, characterization, and evaluation of the cytotoxic activity of sixteen Cu(I)/Triphenylphosphine complexes containing the acylthiourea or naphthoquinones ligands are presented. The complexes were divided into two series based on the classes of the ligands used. The first series is composed of the neutral complexes of general formula [Cu(Ln)(PPh3)2] (1-6) and monocationic complexes of general formula [Cu(Ln)(PPh3)2]NO3 (1a 6a), where Ln= acylthiourea and PPh3= triphenylphosphine. The second series is composed of the neutral complexes of general formula [Cu(NQn)(PPh3)2] (1b 4b), where NQn= naphthoquinone and PPh3= triphenylphosphine. All complexes were characterized by different techniques such as elemental analysis, molar conductivity, infrared absorption spectroscopy, 1D and 2D nuclear magnetic resonance (31P{1H}, 1H and 13C{1H}), mass spectrometry, and X-ray diffraction. In the 13C{1H} NMR spectra, the complexes (1-6) stood out by showing the unusual chemical shift pattern, for the C=O and C=S carbon atoms of the acylthiourea ligand after bidentate (S, O) and anionic coordination. The experimental results were supported by DFT studies that suggested that relativistic effects strongly influenced the NMR protection constants of the light atoms due to coordination to the heavy atom Cu. The stability of the complexes in the cell culture medium was investigated and all the complexes were shown to be unstable, directly influencing the biological results obtained. The in vitro cytotoxicity of the complexes was determined in the breast (MCF7 and MDA MB-231) and lung (A549) tumor cell lines and in the corresponding non-tumor breast (MCF-10A) and lung (MRC-5) cell lines, and all complexes were actives exhibiting IC50 values in the same range in different cell lines. The compounds were more active than the free ligands and the precursor salt of the complexes in different cell lines, showing that even unstable complexes are relevant for the cytotoxic action. In general, the acylthiourea series complexes, 1 and 1a, were able to change the morphology of MDA-MB-231 cells, inhibit colony formation, showing cytotoxic and cytostatic effects on this cell line, significantly altering the cytoskeleton of cells, reducing the density, and promoting the condensation of the F-actin filaments. They promoted the increase of cells in the fragmented DNA region (sub-G0) and induced cell death by apoptosis. The complexes of the naphthoquinone series, 1b, and 4b, altered the morphology of MDA-MB-231 cells, inhibited colony formation at concentrations higher than the IC50, and were able to inhibit cell migration. Finally, the compounds synthesized and characterized in this work are relevant reports of copper (I) complexes with cytotoxic properties in different tumor cell lines with potential for future studies in vivo models.
Innovation ecosystems and strategy in the COVID-19 crisis
(Universidade Federal de São Carlos, 2021-07-26) Oliveira, Wesley da Paixão de; Guimarães, Márcia Regina Neves; https://lattes.cnpq.br/9250214706491925; Silva, João Eduardo Azevedo Ramos da; https://lattes.cnpq.br/3823047207711289; https://lattes.cnpq.br/6161303614779679
The COVID-19 pandemic is a disturbance that forced enterprises to rethink their strategies and ecosystems to keep running. Nevertheless, there is a lack of prior register to show the best policies to adopt in such circumstances. Hence, researchers and practitioners must comprehend how companies are responding to this unprecedented health crisis. Furthermore, it is of equal importance to comprehend the pandemic consequences on ventures’ strategies and ecosystems. In this sense, the research identified how four ventures handled such a situation. Through a multiple and holistic case study, supported by exploratory and qualitative approaches, the research provided a detailed description of their competitive strategies, innovation ecosystems, and the adopted measures against the crisis. The main findings were as follows: (i) The pandemic affected the studied ventures and ecosystems at different levels. The crisis severely hit the approached enterprises and ecosystems from the event and consultancy industries, especially the former. For example, the former entirely ceased their activities for a while, impacting the ecosystem activity flow. However, the pandemic boosted the businesses of the organizations and ecosystems from the telehealth and medication industries. For example, the medication case showed no change in its ecosystem composition and further capitalized from new projects that emerged due to the COVID-19 disruption. (ii) The ventures proposed changes related to the value proposition, interaction process, and activities and information flow across the ecosystem to keep running. For example, those severely affected by the COVID-19 succeeded in delivering their solutions entirely online (the consultancy industry case) or avoiding crowds (the event industry case). Further, those less affected benefited by adopting work from home (the medication industry case) or serving occupational health and safety care entirely online (the telehealth industry case). (iii) The enterprises employed these modifications mainly by adopting (the medication and telehealth industries cases) or increasing (the event and consultancy industries cases) digital solutions internally and crosswise the ecosystems. Therefore, the studied cases' competitive strategy and innovation ecosystems goals have not changed due to the pandemic: what changed was the means to achieve these objectives to respond to the crisis and keep moving forward.