3,046 research outputs found
A rational experimental approach to identify correctly the working voltage window of aqueous-based supercapacitors
It is common to find in the literature different values for the working voltage window (WVW) range for aqueous-based supercapacitors. In many cases, even with the best intentions of the widening the operating voltage window, the measured current using the cyclic voltammetry (CV) technique includes a significant contribution from the irreversible Faradaic reactions involved in the water-splitting process, masked by fast scan rates. Sometimes even using low scan rates is hard to determine precisely the correct WVW of the aqueous-based electrochemical capacitor. In this sense, we discuss here the best practices to determine the WVW for capacitive current in an absence of water splitting using complementary techniques such as CV, chronoamperometry (CA), and the electrochemical impedance spectroscopy (EIS). To accomplish this end, we prepare and present a model system composed of multiwalled carbon nanotubes buckypaper electrodes housed in the symmetric coin cell and soaked with an aqueous-based electrolyte. The system electrochemical characteristics are carefully evaluated during the progressive enlargement of the cell voltage window. The presence of residual Faradaic current is verified in the transients from the CA study, as well as the impedance changes revealed by EIS as a function of the applied voltage, is discussed. We verify that an apparent voltage window of 2.0 V determined using the CV technique is drastically decreased to 1.2 V after a close inspection of the CA findings used to discriminate the presence of a parasitic Faradaic process. Some orientations are presented to instigate the establishment in the literature of some good scientific practices concerned with the reliable characterization of supercapacitors10CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP310544/2019-0; 301095/2018-32014/02163-7; 2017/11958-1; 2018/20756-
The plasticity of non-crystalline solids: aluminum phosphate white pigments
A new white pigment made out of nano-structured non-crystalline aluminum phosphate was recently launched as an industrial product. Pigment opacifying properties are not intrinsic to aluminum phosphate but they arise as the result of a rare hollow particle nano-structure. This is in turn derived from the core-and-shell structure of amorphous aluminum phosphate precipitated under well-defined conditions. The new pigment is a product of the often neglected chemistry of non-crystalline ionic solids that can probably be a rich source of new successful products. The text describes a short account of the R&D activities, from the initial ideas to the present.745748Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
Comprehensive molecular landscape of cetuximab resistance in head and neck cancer cell lines
Cetuximab is the sole anti-EGFR monoclonal antibody that is FDA approved to treat head and neck squamous cell carcinoma (HNSCC). However, no predictive biomarkers of cetuximab response are known for HNSCC. Herein, we address the molecular mechanisms underlying cetuximab resistance in an in vitro model. We established a cetuximab resistant model (FaDu), using increased cetuximab concentrations for more than eight months. The resistance and parental cells were evaluated for cell viability and functional assays. Protein expression was analyzed by Western blot and human cell surface panel by lyoplate. The mutational profile and copy number alterations (CNA) were analyzed using whole-exome sequencing (WES) and the NanoString platform. FaDu resistant clones exhibited at least two-fold higher IC50 compared to the parental cell line. WES showed relevant mutations in several cancer-related genes, and the comparative mRNA expression analysis showed 36 differentially expressed genes associated with EGFR tyrosine kinase inhibitors resistance, RAS, MAPK, and mTOR signaling. Importantly, we observed that overexpression of KRAS, RhoA, and CD44 was associated with cetuximab resistance. Protein analysis revealed EGFR phosphorylation inhibition and mTOR increase in resistant cells. Moreover, the resistant cell line demonstrated an aggressive phenotype with a significant increase in adhesion, the number of colonies, and migration rates. Overall, we identified several molecular alterations in the cetuximab resistant cell line that may constitute novel biomarkers of cetuximab response such as mTOR and RhoA overexpression. These findings indicate new strategies to overcome anti-EGFR resistance in HNSCC.This work was supported by Barretos Cancer Hospital and the Public Ministry of Labor
Campinas (Research, Prevention, and Education of Occupational Cancer) in Campinas, Brazil, CAPESDFATD (88887.137283/2017-00). INFG is the recipient of a FAPESP Ph.D. fellowship (2017/22305-9)
Filling data gaps on the diversity and distribution of Amazonian bats (Chiroptera): the case of Amapá, easternmost Brazil
Discovery of the Anticancer Activity for Lung and Gastric Cancer of a Brominated Coelenteramine Analog
Supplementary Materials: The following supporting information can be downloaded at: https:
//www.mdpi.com/article/10.3390/ijms23158271/s1.Cancer is still a challenging disease to treat, both in terms of harmful side effects and therapeutic efficiency of the available treatments. Herein, to develop new therapeutic molecules, we have investigated the anticancer activity of halogenated derivatives of different components of the bioluminescent system of marine Coelenterazine: Coelenterazine (Clz) itself, Coelenteramide (Clmd), and Coelenteramine (Clm). We have found that Clz derivatives possess variable anticancer activity toward gastric and lung cancer. Interestingly, we also found that both brominated Clmd (Br-Clmd) and Clm (Br-Clm) were the most potent anticancer compounds toward these cell lines, with this being the first report of the anticancer potential of these types of molecules. Interestingly, Br-Clm possessed some safety profile towards noncancer cells. Further evaluation revealed that the latter compound induced cell death via apoptosis, with evidence for crosstalk between intrinsic and extrinsic pathways. Finally, a thorough exploration of the chemical space of the studied Br-Clm helped identify the structural features responsible for its observed anticancer activity. In conclusion, a new type of compounds with anticancer activity toward gastric and lung cancer was reported and characterized, which showed interesting properties to be considered as a starting point for future optimizations towards obtaining suitable chemotherapeutic agents.The Portuguese “Fundação para a Ciência e Tecnologia“ (FCT) is acknowledged for funding project PTDC/QUI-QFI/2870/2020, the R&D Units CIQUP (UIDB/00081/2020), GreenUPorto
(UIDB/05748/2020), LAQV/REQUIMTE (UIDB/50006/2020), and the Associated Laboratory IMS
(LA/P/0056/2020). L. Pinto da Silva acknowledges funding from FCT under the Scientific Employ ment Stimulus (2021.00768.CEECIND). Patricia González-Berdullas acknowledges funding for her
postdoctoral position in the framework of project PTDC/QUI/QFI/2870/2020. Carla Magalhães
acknowledges FCT for her PhD grant (SRFH/BD/143211/2019). Renato B. Pereira acknowledges
PRIMA Foundation (H2020- PRIMA 2018—Section 2, Project MILKQUA) and FCT (PTDC/QUI QFI/2870/2020) for the funding
Determinação do ponto de amostragem para a obtenção da concentração média de tanino em acácia.
The height of the sampling point in acacia trees, where the medium tannin concentration is located, was studied for black acacia, Acacia mearnsii De Willd. The equation hi/h=1.22747 -0.046494.CTA was obtained relating the sample height over the total height to the tannin concentration. Substituing the medium value of CTA, 15.52165%, the value 0.401983 is obtained for hi/h. We concluded that the medium concentration of tannin can be determined at a single height, 40% of the total of the tree stem, independent of the age of the tree.A altura de amostragem, nas árvores de acácia onde obtém-se a concentração média de tanino, foi estudado em população de acácia-negra, Acacia mearnsii de Willd. Considerando-se a concentração de tanino (CTA) em função da relação altura de amostragem (hi) sobre a altura total (h), obteve-se a seguinte equação: hi/h = 1,122747 - 0,046494 · CTA. Substituindo-se CTA na equação, pelo valor médio da concentração de tanino encontrado de 15,52165%, chegou-se ao valor hi/h = 0,401083. Isto permitiu concluir que a concentração média de tanino pode ser determinada num único ponto de amostragem, localizado a 40% da altura total das árvores, independente da idade
Determinação do ponto de amostragem para a obtenção da concentração média de tanino em acácia.
Zika Virus Disrupts Molecular Fingerprinting Of Human Neurospheres
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Zika virus (ZIKV) has been associated with microcephaly and other brain abnormalities; however, the molecular consequences of ZIKV to human brain development are still not fully understood. Here we describe alterations in human neurospheres derived from induced pluripotent stem (iPS) cells infected with the strain of Zika virus that is circulating in Brazil. Combining proteomics and mRNA transcriptional profiling, over 500 proteins and genes associated with the Brazilian ZIKV infection were found to be differentially expressed. These genes and proteins provide an interactome map, which indicates that ZIKV controls the expression of RNA processing bodies, miRNA biogenesis and splicing factors required for self-replication. It also suggests that impairments in the molecular pathways underpinning cell cycle and neuronal differentiation are caused by ZIKV. These results point to biological mechanisms implicated in brain malformations, which are important to further the understanding of ZIKV infection and can be exploited as therapeutic potential targets to mitigate it.7Brazilian Development Bank (BNDES)Funding Authority for Studies and Projects (FINEP)National Council of Scientific and Technological Development (CNPq)Foundation for Research Support in the State of Rio de Janeiro (FAPERJ)Sao Paulo Research Foundation (FAPESP) [14/21035-0, 14/14881-1, 13/08711-3, 14/10068-4]Coordination for the Improvement of Higher Education Personnel (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES
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