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19th Brazilian meeting on analytical chemistry
(2020-03) Coltro, Wendell Karlos Tomazelli; Rocha, Fábio Rodrigo Piovezani; Teixeira, Leonardo Sena Gomes; Sodré, Fernando Fabriz; Santelli , Ricardo Erthal; Kubota , Lauro Tatsuo; Nóbrega, Joaquim de Araújo; Ferreira, Sergio Luis Costa
1H HR-MAS NMR and S180 cells: metabolite assignment and evaluation of pulse sequence
(2014-04) Oliveira, Aline Lima de; Martinelli, Bruno César Barbosa; Liao, Luciano Morais; Pereira, Flávia de Castro; Lacerda, Elisângela de Paula Silveira; Alcantara, Glaucia Braz
High resolution magic angle spinning 1H nuclear magnetic resonance spectroscopy (HR-MAS NMR) is a useful technique for evaluation of intact cells and tissues. However, optimal NMR parameters are crucial in obtaining reliable results. To identify the key steps for the optimization of HR-MAS NMR parameters, we assessed different pulse sequences and NMR parameters using sarcoma 180 (S180) cells. A complete assignment of the metabolites of S180 is given to assist future studies.
1H HRMAS NMR spectroscopy and chemometrics for evaluation of metabolic changes in citrus sinensis caused by xanthomonas axonopodis pv. citri
(2012-05) Silva, Lorena Mara Alexandre e; Alves Filho, Elenilson de Godoy; Choze, Rafael; Liao, Luciano Morais; Alcantara, Glaucia Braz
Xanthomonas axonopodis (Xac) bacterium causes one of the most feared and untreatable diseases in citriculture: citrus canker. To understand the response mechanisms of orange trees when attacked by Xac, leaves and fruits of Citrus sinensis were directly evaluated by HRMAS NMR (high resolution magic angle spinning nuclear magnetic resonance) spectroscopy. This technique allows the analysis of samples without laborious pre-treatments and also allows access to important information about chemical composition of samples. The orange tree leaves and fruit peels investigated in this study demonstrated the biochemical changes caused by Xac. Aided by chemometric analysis, the HRMAS NMR results show relevant changes in amino acids, carbohydrates, organic acids and terpenoids content.
2,5-diketopiperazines via intramolecular N-alkylation of Ugi adducts: a contribution to the synthesis, density functional theory study, X-ray characterization, and potential herbicide application
(2022) Mendes, Lorena Lessa; Varejão, Jodieh Oliveira Santana; Sousa, José Antonio de; Carneiro, José Walkimar de Mesquita; Valdo, Ana Karoline Silva Mendanha; Martins, Felipe Terra; Ferreira, Bruno Wesley; Barreto, Robert Weingart; Silva, Toshik Iarley da; Kohlhoff, Markus; Pilau, Eduardo Jorge; Varejão, Eduardo Vinícius Vieira
To investigate the herbicidal potential of 2,5-diketopiperazines (2,5-DKPs), we applied a known protocol to produce a series of 2,5-DKPs through intramolecular N-alkylation of Ugi adducts. However, the method was not successful for the cyclization of adducts presenting aromatic rings with some substituents at the ortho position. Results from DFT calculations showed that the presence of voluminous groups at the ortho position of a benzene ring results in destabilization of the transition structure. Lower activation enthalpies for the SN2-type cyclization of Ugi adducts were obtained when bromine, instead of a chlorine anion, is the leaving group, indicating that the activation enthalpy for the cyclization step controls the formation of the 2,5-DKP. Some Ugi adducts and 2,5-DKPs formed crystals with suitable qualities for single-crystal X-ray diffraction data collection. Phytotoxic damage of some 2,5-DKPs on leaves of the weed Euphorbia heterophylla did not differ from those caused by the commercial herbicide diquat.
2-(4-iodo-2,5-dimetoxifenil)-N-[(2-metoxifenil)metil]etamina ou 25I-NBOMe: caracterização química de uma designer drug
(2016) Santos, Pâmella Ferraz dos; Souza, Lindamara Maria de; Merlo, Bianca Bortolini; Costa, Helber Barcellos da; Tose, Lilian Valadares; Santos, Heloa; Costa, Gabriela Vanini; Machado, Leandro Fernandes; Ortiz, Rafael Scorsatto; Limberger, Renata Pereira; Vaz, Boniek Gontijo; Romão, Wanderson
Drug trafficking and the introduction of new drugs onto the illicit market are one of the main challenges of the forensic community. In this study, the chemical profile of a new designer drug, 2-(4-iodine-2,5- dimethoxyphenyl)-n-[(2-methoxyphenyl)methyl]etamine or 25I-NBOMe was explored using thin layer chromatography (TLC), ultraviolet-visible spectrophotometry (UV-Vis), attenuated total reflection with Fourier transform infrared spectroscopy(ATRFTIR), gas chromatography mass spectrometry (GC-MS) and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR MS). First, the TLC technique was effective for identifying spots related to 25C-, 25B- and 25I-NBOMe compounds, all with the same retention factor, Rf ≈ 0.50. No spot was detected for 2,5-dimethoxy-4-bromoamphetamine, 2,5-Dimethoxy-4-chloroamphetamine or lysergic acid diethylamide compounds. ATR-FTIR preserved the physical-chemical properties of the material, whereas GC-MS and ESI-MS showed better analytical selectivity. ESI(+)FT-ICR MS was used to identify the exact mass (m/z 428.1706 for the [M + H]+ ion), molecular formula (M = C18H22INO3), degree of unsaturation (DBE = 8) and the chemical structure (from collision induced dissociation, CID, experiments) of the 25I-NBOMe compound. Furthermore, the ATR-FTIR and CID results suggested the presence of isomers, where a second structure is proposed as an isomer of the 25I-NBOMe molecule.
2-(Pyridin-4yl)benzothiazole and Its benzimidazole-analogue: biophysical and in silico studies on their interaction with urease and in vitro anti-Helicobacter pylori activities
(2022) Pereira, Camila de Paula; Lyra, Ana Carolina Fradique de; Oliveira, Breno Germano de Freitas; Nascimento, Igor José dos Santos; Silva Júnior, Edeildo Ferreira da; Aquino, Thiago Mendonça de; Sisto, Francesca; Figueiredo, Isis Martins; Martins, Felipe Terra; Modolo, Luzia Valentina; Santos, Josué Carinhanha Caldas; Fátima, Ângelo de
In this study, the interaction between benzothiazole (BTA, concentration of a drug required for 50% inhibition in vitro (IC50) = 0.77 mM) and benzimidazole (BIA, IC50 = 2.14 mM) with urease was quantitatively assessed, using UV-Vis, molecular fluorescence, and circular dichroism. The results showed that both compounds interact with urease by a static fluorescence quenching mechanism with a non-fluorescent complex formation. The main forces responsible for stabilizing the supramolecular complex between BTA and urease were hydrophobic while, for BIA, van der Waals interactions and hydrogen bonds were the main ones. Urease conformation changes due to the interaction process were analyzed by circular dichroism and synchronous fluorescence. Besides, a competitive assay with substrate and inhibitors was used to evaluate the preferential urease site of interaction with BTA and BIA. Our experimental and theoretical studies supported that both, BTA and BIA, are mixed-inhibitors of ureases with a slight preference to the active site of such enzymes. Finally, both BTA and BIA showed to possess anti-Helicobacter pylori (one reference strain and six clinical isolates) activity, presenting minimal inhibitory concentration (MIC) values ranging from 38-150 and 20-164 µM, respectively. The urease inhibitors omeprazole and hydroxyurea showed MIC values in the range of 46-185 µM and 1683-> 3366 µM, respectively.
25I-NBOH: a new potent serotonin 5-HT2A receptor agonist identified in blotter paper seizures in Brazil
(2017-02-16) Arantes, Luciano Chaves; Ferrari Júnior, Ettore; Souza, Luciano Figueiredo de; Cardoso, Andriele Costa; Alcantara, Thaynara Lino Fernandes; Liao, Luciano Morais; Machado, Yuri; Lordeiro, Rogério Araújo; Coelho Neto, José; Andrade, Ana Flávia Belchior de
A new potent serotonin 5-HT2A receptor agonist was identified in blotter papers by several state level forensic laboratories in Brazil. The 25I-NBOH is a labile molecule, which fragments into 2C-I when analyzed by routine seized material screening gas chromatography (GC) methods. GC–mass spectrometry (MS), liquid chromatography–quadrupole time-of-flight-MS, and Fourier transform infrared and nuclear magnetic resonance analyses were performed to complete molecular characterization. Individual doses range from 300 to 1000 lg. Despite its being a potent 5-HT2A receptor agonist, 25I-NBOH is neither registered in the United Nations Office on Drugs and Crime (UNODC) nor classified as a scheduled substance in most countries. Sweden and Brazil seem to be the only countries to control 25I-NBOH. To our knowledge, this is the first scientific report dealing with identification of 25I-NBOH in actual seizures.
2D and 3D mixed MII/CuII metal–organic frameworks (M = Ca and Sr) with N,N′-2,6-pyridinebis(oxamate) and oxalate: preparation and magneto-structural study
(2018) Fernandes, Tamires Soares; Melo, Wanessa David Canedo; Kalinke, Lucas Hoffmann Greghi; Souza Filho, Renato Rabelo de; Valdo, Ana Karoline Silva Mendanha; Silva, Cameron Capeletti da; Martins, Felipe Terra; Amorós, Pedro; Lloret Pastor, Francesc; Julve Olcina, Miguel; Gomes, Danielle Cangussu de Castro
Three heterobimetallic complexes of formula [Ca2Cu3(mpyba)2(2-apyma)(H2O)7]·8.3H2O (1), [Sr2Cu3(mpyba)2(2-apyma)(H2O)8]·11.6H2O (2) and [Sr4.5Cu4(mpyba)4(ox)(H2O)20]·8.5H2O (3) [H4mpyba = N,N′-2,6-pyridinebis(oxamic acid), 2-apyma = 2-(6-aminopyridinyl)oxamate and ox = oxalate] have been synthesized and structurally characterized. Complexes 1 and 2 are isostructural compounds, with tricopper(II) units having mpyba and its hydrolytic product (2-apyma) as ligands. They are interlinked through strontium(II) (1) and calcium(II) (2) ions to afford neutral two-dimensional networks. Two of the copper(II) ions are five-coordinate in distorted square pyramidal (Cu3) and trigonal bipyramidal (Cu1) surroundings, whereas the other (Cu2) is six-coordinate in an elongated octahedral environment. The main difference between their structures, apart from the number of water molecules, resides in the nature of the alkaline earth cation coordinated to the oxamate fragments, Sr2+ (1)/Ca2+ (2), which exhibit eight and seven coordination, respectively. The π–π interactions and an extensive network of hydrogen bonds in 1 and 2 lead to supramolecular 3D structures. The relatively small size of their cavities, in the micropore domain, hinders the inclusion of N2 but allows CO2 adsorption (0.45 and 0.52 mmol g−1 for 1 and 2, respectively). The structure of 3 is made up of [3,3] metallacyclophane-type motifs, having the formula [Cu2(mpyba)2(H2O)2]4−. These act as tetrakis(bidentate) ligands towards the strontium(II) ions (Sr1, Sr2 and Sr3), leading to a sheet-like polymer growing in the bc plane, which extends further along the crystallographic a axis by a bis(chelating) oxalate between the Sr1 atoms. The investigation of the magnetic properties of 1–3 in the temperature range 1.9–300 K shows the occurrence of an overall antiferromagnetic behaviour for 1 and 2 [J12 = J23 = −9.71(2) (1) and −10.81(5) cm−1 (2), with the Hamiltonian being defined as H = −J12S1·S2 − J23S2·S3 + gβH[S1 + S2 + S3], and a ferromagnetic coupling within the dicopper(II) metallacylophane unit of 3 [J = +1.86(1) cm−1 through the Hamiltonian H = −JS1·S2 + gβH(S1 + S2)]. Simple orbital symmetry considerations (1–3) and the spin polarization mechanism (3) account for the observed magnetic properties.
3-phenacylideneoxindoles as a new class of antifungal compounds against Paracoccidioides spp
(2023-01-20) Silva, Lívia do Carmo; Santos Filho, Raimundo Francisco dos; Oliveira, Amanda Alves de; Martins, Felipe Terra; Cunha, Silvio do Desterro; Soares, Célia Maria de Almeida; Pereira, Maristela
Aims: Considering the need to identify new compounds with antifungal action, the activity of five 3-phenacylideneoxindoles compounds was evaluated. Materials & methods: The compounds were synthesized, and their antifungal activity was elucidated through minimum inhibitory concentration tests and interaction assay with other antifungals. Potential targets of compounds were predicted in silico. Results: 3-phenacylideneoxindoles compounds inhibited fungal growth with minimum inhibitory concentration and minimum fungicidal concentration ranging from 3.05 to 12.26 μM. The compounds demonstrated high selectivity index and presented a synergistic effect with itraconazole. In silico prediction revealed the pentafunctional AROM polypeptide, enolase, superoxide dismutase, catalase and kinases as proteins targets of the compound 4a. Conclusion: The results demonstrate that 3-phenacylideneoxindoles is a potential new class of antifungal compounds for paracoccidioidomycosis treatment.
3D printed microfluidic mixer for real-time monitoring of organic reactions by direct infusion mass spectrometry
(2022) Duarte, Lucas da Costa; Silva, Igor Pereira da; Maciel, Lanaia Ítala Louzeiro; Vaz, Boniek Gontijo; Coltro, Wendell Karlos Tomazelli
3D printing is a technology that has revolutionized traditional rapid prototyping methods due to its ability to build microscale structures with customized geometries in a simple, fast, and low-cost way. In this sense, this article describes the development of a microfluidic mixing device to monitor chemical reactions by mass spectrometry (MS). Microfluidic mixers were designed containing 3D serpentine and Y-shaped microchannels, both with a pointed end for facilitating the spray formation. The devices were fabricated entirely by 3D printing with fusion deposition modeling (FDM) technology. As proof-of-concept, micromixers were evaluated through monitoring the Katritzky reaction by injecting simultaneously 2,4,6-triphenylpropyllium (TPP) and amino acid (glycine or alanine) solutions, each through a different reactor inlet. Reaction product was monitored online by MS at different flow rates. Mass spectra showed that the relative abundances of the products obtained with the device containing the 3D serpentine channel were three times greater than those obtained with the Y-channel device due to the turbulence generated by the barriers created inside microchannels. In addition, when compared to the conventional electrospray ionization mass spectrometry (ESI-MS) technique, the 3D serpentine mixer offered better performance measured in relation to the relative abundance values for the reaction products. These results as well as the instrumental simplicity indicate that 3D printed microfluidic mixer is a promising tool for monitoring organic reactions via MS.
3D printing of compact electrochemical cell for sequential analysis of steroid hormones
(2022) Duarte, Lucas da Costa; Baldo, Thaisa Aparecida; Silva Neto, Habdias de Araujo; Figueredo, Federico; Janegitz, Bruno Campos; Coltro, Wendell Karlos Tomazelli
3D printing technology revolutionized the development of electrochemical sensors allowing the fabrication of custom devices that can be adapted to meet specific applications. This study describes the development of a miniaturized electrochemical cell containing integrated electrodes manufactured entirely by 3D printing for the sequential detection of steroid hormones. The electrochemical sensor was manufactured in a single step by combining two types of thermoplastic filaments. Polylactic acid-Carbon Black (PLA-CB) was used in the electrode region and acrylonitrile butadiene styrene (ABS) was used in the insulating region. Chemical/electrochemical treatments were used to remove the inert polymer matrix and expose the electroactive sites of the CB electrodes. These pre-treatment procedures significantly enhanced the electrochemical response of the printed sensor. The analytical performance of the activated 3D printed electrochemical cell was demonstrated in the sequential detection of estradiol (E2) and progesterone (P4) in artificial urine. The electrochemical cell offered good repeatability (RSD = 3.1%) and reproducibility (RSD = 10.7%) between analyses reaching detection limits of 0.11 and 17.8 µmol L-1 for E2 and P4, respectively. In this sense, these results demonstrate that the use of 3D printing paves the way for the fast and economical fabrication of miniaturized electrochemical cells for hormone detection in biological fluids.
3D printing of microfluidic devices for paper-assisted direct spray ionization mass spectrometry
(2016) Duarte, Lucas da Costa; Carvalho, Thays Colletes de; Lobo Júnior, Eulício de Oliveira; Abdelnur, Patrícia Verardi; Vaz, Boniek Gontijo; Coltro, Wendell Karlos Tomazelli
This study describes the use of a 3D printer to fabricate microfluidic devices for direct spray ionization mass spectrometry (DS-MS) assisted by paper tips. The layout of the proposed devices was designed in a three-dimensional model through a computer-aided design system and printed by a fused deposition modeling method using a thermoplastic filament composed of acrylonitrile butadiene styrene deposited layer by layer. The smallest channel width was 400 μm to ensure 3D printing uniformity without any obstruction. For DS-MS studies, microfluidic channels consisted of a single channel connected to a sample reservoir (3 mm diameter). The printed channel was 3 cm long, 500 μm wide and 500 μm deep. Paper tips (0.5 cm long × ca. 0.5 mm wide) were manually cut and inserted into the extremity of the printed channel to facilitate the spray formation. The spray was promoted by the application of 4 kV at the sample reservoir containing 0.1% formic acid prepared in methanol. This organic medium selected for MS experiments has demonstrated great compatibility with the polymeric material employed to create microfluidic chips. 3D printed devices were kept at a distance of 3 mm from the MS entrance. Using glucose solution as the model, the formed spray by the proposed microfluidic device was extremely stable in comparison to traditional paper spray ionization devices for at least 10 min. The analytical feasibility of printed devices for DS-MS was successfully demonstrated by qualitative analysis of ballpoint pen inks, caffeine, xylose and lysozyme. The 3D printer has allowed the fabrication of printed devices at a very low cost ($0.05) within 20 min. Furthermore, 3D printed devices have exhibited significant repeatability and reproducibility, making their reuse possible. Based on the performance of the proposed devices, we believe they can be used in a broad range of bioanalytical applications.
3D printing of microfluidic devices with embedded sensing electrodes for generating and measuring the size of microdroplets based on contactless conductivity detection
(2017-11) Duarte, Lucas da Costa; Chagas , Cyro Lucas Silva; Ribeiro, Luiz Eduardo Bento; Coltro, Wendell Karlos Tomazelli
This report describes the 3D printing of integrated microfluidic platforms containing microchannels and embedded sensing electrodes for capacitively coupled contactless conductivity detection (C4D). Sensing electrodes were printed on poly(lactic acid) filament doped with carbon nanotubes and then integrated with fluidic channels printed on acrylonitrile butadiene styrene. The proposed microfluidic chips were explored to generate and measure the size of microdroplets based on C4D measurements. To the best of our knowledge, this is the first report showing the entire fabrication of an integrated platform by 3D printing as well as its use for measuring the size of droplets. The proof-of-concept was successfully demonstrated by generating oil droplets in an aqueous phase and water droplets in an oil phase. The droplet sizes were estimated based on their residence time within the detection cell in association with the flow velocity. According to the data achieved by C4D measurements, the length of water droplets decreased from 3.4 ± 0.1 to 2.3 ± 0.1 mm when the total flow rate raised from 15 to 55 μL min−1. For oil droplets, length values ranged from 3.6 ± 0.1 to 2.4 ± 0.1 mm at the same flow rate range. The achieved results exhibited an exponential correlation with the data obtained by optical measurements.
3D-printed electrochemical platform with multi-purpose carbon black sensing electrodes
(2022-05-28) Silva Neto, Habdias de Araujo; Dias, Anderson Almeida; Coltro, Wendell Karlos Tomazelli
The 3D printing is described of a complete and portable system comprising a batch injection analysis (BIA) cell and an electrochemical platform with eight sensing electrodes. Both BIA and electrochemical cells were printed within 3.4 h using a multimaterial printer equipped with insulating, flexible, and conductive filaments at cost of ca. ~ U$ 1.2 per unit, and their integration was based on a threadable assembling without commercial component requirements. Printed electrodes were exposed to electrochemical/Fenton pre-treatments to improve the sensitivity. Scanning electron microscopy and electrochemical impedance spectroscopy measurements upon printed materials revealed high-fidelity 3D features (90 to 98%) and fast heterogeneous rate constants ((1.5 ± 0.1) × 10−3 cm s−1). Operational parameters of BIA cell were optimized using a redox probe composed of [Fe(CN)6]4−/3− under stirring and the best analytical performance was achieved using a dispensing rate of 9.0 µL s−1 and an injection volume of 2.0 µL. The proof of concept of the printed device for bioanalytical applications was evaluated using adrenaline (ADR) as target analyte and its redox activities were carefully evaluated through different voltammetric techniques upon multiple 3D-printed electrodes. The coupling of BIA system with amperometric detection ensured fast responses with well-defined peak width related to the oxidation of ADR applying a potential of 0.4 V vs Ag. The fully 3D-printed system provided suitable analytical performance in terms of repeatability and reproducibility (RSD ≤ 6%), linear concentration range (5 to 40 µmol L−1; R2 = 0.99), limit of detection (0.61 µmol L−1), and high analytical frequency (494 ± 13 h−1). Lastly, artificial urine samples were spiked with ADR solutions at three different concentration levels and the obtained recovery values ranged from 87 to 118%, thus demonstrating potentiality for biological fluid analysis. Based on the analytical performance, the complete device fully printed through additive manufacturing technology emerges as powerful, inexpensive, and portable tool for electroanalytical applications involving biologically relevant compounds.
4-Fluorobenzaldehyde limonene-based thiosemicarbazone induces apoptosis in PC-3 human prostate cancer cells
(2018) Rodrigues, Bruna dos Santos; Marcelino, Renato Ivan de Ávila; Miranda, Polyana Lopes Benfica; Pires, Ludmila Bringel; Oliveira, Cecilia Maria Alves de; Vandresen, Fábio; Silva, Cleuza Conceição da; Valadares, Marize Campos
Aims: This study evaluated parameters of toxicity and antiproliferative effects of (+)-N(1)-4-fluorobenzaldehyde-N(4)-{1-methyl-1-[(1R)-4-methylcyclohexene-3-il]-ethyl}-thiossemicarbazone (4-FTSC) in PC-3 adenocarcinoma prostate cells. Main methods: Cytotoxicity of 4-FTSC in PC-3 cells was evaluated using MTT assay. Morphology examination of PC-3 cells treated with 4-FTSC was also performed as well as the cell death mechanisms induced were investigated using flow cytometry. Parameters of toxicity of 4-FTSC was conducted by the investigation of its potential myelotoxicity and lymphotoxicity, hemolytic activity and acute oral toxicity profile. Key findings: 4-FTSC showed promising cytotoxic effects against PC-3 cells (IC50 = 18.46 μM). It also triggered apoptotic morphological changes, phosphatidylserine externalization and a significant increase of DNA fragmentation in PC-3 cells. Moreover, 4-FTSC did not show changes in the PC-3 cell cycle with levels of p21, p27, NFĸB and cyclin D1 similar to those found in both control and treated cells. 4-FTSC also promoted an increase of p53 levels associated with mitochondrial impairment through loss of ∆Ψm and ROS overproduction. 4-FTSC-induced cell death mechanism in PC-3 cells involved activation of caspase-3/-7 through apoptosis intrinsic pathway via caspase-9. Regarding toxicological profile, 4-FTSC showed in vitro lymphotoxicity, although with low cytotoxicity for bone marrow progenitors and no hemolytic potential. Moreover, it was classified as GHS category 5 (LD50 > 2000–5000 mg/Kg), suggesting it has low acute oral systemic toxicity. Significance: 4-FTSC seems to be a promising candidate to be used as a clinical tool in prostate cancer treatment. Further studies are required to better clarify its toxicopharmacological effects found in this compound.
A benzothiadiazole-quinoline hybrid sensor for specific bioimaging and surgery procedures in mice
(2021) Medeiros, Gisele Alves; Corrêa, José Raimundo; Andrade, Lorena Pereira de; Lopes, Thiago Oliveira; Oliveira, Heibbe Cristhian Benedito de; Diniz, Ariane Barros; Menezes, Gustavo Batista de; Rodrigues, Marcelo Oliveira; Silveira Neto, Brenno Amaro da
The work describes the design, synthesis, characterization and biological application (bioimaging) of a new hybrid and fluorescent 2,1,3-benzothiadiazole-quinoline sensor. Both photophysical data of the designed compound and DFT calculations have indicated its high stability and have pointed to its possible efficient application as a bioprobe for bioimaging experiments. The new sensor has been designed to display lipophilic character being capable of selectively stain lipid bodies independent whether live and fixed cancer cells were used. The fluorescent sensor has also been tested as a specific bioimaging marker for C. elegans (complex multicellular model) and has showed far better selectivity in the worm than the commercially available BODIPY. A live mice has been submitted to a surgery procedure and the adipocytes (lipid-rich) cells have been differentiated from standard cells. Experiments using high fat fed mice have enabled a high-resolution 3D image reconstruction. Also, in another surgery procedure, hepatocyte cells could have been successfully followed in the blood flow using the designed sensor in a multistaining procedure alongside with a commercially available blue emitting nuclei marker.
A blue-light-emitting cadmium coordination polymer with 75.4% photoluminescence quantum yield
(2019) Nascimento Neto, José Antônio do; Valdo, Ana Karoline Silva Mendanha; Silva, Cameron Capeletti da; Guimarães, Freddy Fernandes; Queiroz Júnior, Luiz Henrique Keng; Maia, Lauro June Queiroz; Santana, Ricardo Costa de
We report a novel bright deep-blue-emitting crystal form based on a simple cadmium coordination polymer with an impressive external photoluminescence quantum yield of 75.4(9)%.
A comparative study on the crystal structure of bicycle analogues to the natural phytotoxin helminthosporins
(2016) Barbosa, Luiz Cláudio de Almeida; Teixeira, Róbson Ricardo; Nogueira, Leonardo Brandão; Maltha, Celia Regina Alvares; Doriguetto, Antonio Carlos; Martins, Felipe Terra
Herein we described structural insights of a series of analogues to helminthosporin phytotoxins. The key reaction used to prepare the compounds corresponded to the [3 + 4] cycloaddition between the oxyallyl cation generated from 2,4-dibromopentan-3-one and different furans. Their structures were confirmed upon IR, NMR and X-ray diffraction analyses. While bicycles 7, 8 and 9 crystallize in the centrosymmetric monoclinic space group P21/c, compound 10 was solved in the noncentrosymmetric orthorhombic space group P212121. The solid materials obtained were shown to be racemic crystals (7, 8, 9) or racemic conglomerate (10). In all compounds, there is formation of a bicycle featured by fused tetrahydropyranone and 2,5-dihydrofuran rings. They adopt chair and envelope conformations, respectively. Crystal packing of all compounds is stabilized through C–H•••O contacts. Conformational aspects as well as similarities and differences among the crystal structures of the synthesized analogues are discussed.
A comparative study on thermal behavior of solid-state light trivalent lanthanide isonicotinates in dynamic dry air and nitrogen atmospheres
(2016-02-24) Nunes, Wilhan Donizete Gonçalves; Teixeira, José Augusto; Nascimento, André Luiz Carneiro Soares do; Caires, Flávio Junior; Ionashiro, Elias Yuki; Ionashiro, Massao
Characterization, thermal stability, and thermal decomposition of light trivalent lanthanide isonicotinates Ln(L)32H2O (Ln = La to Gd, except Pm; L = isonicotinate) were investigated employing simultaneous thermogravimetry and differential scanning calorimetry (TG– DSC), DSC, infrared spectroscopy (FTIR), evolved gas analysis by TG–DSC coupled to FTIR, elemental analysis, and complexometry. The dehydration of these compounds occurs in a single step, and the thermal decomposition of the anhydrous compounds occurs in one or two (air) and two or three steps (N2). The final residues of thermal decomposition were CeO2, Pr6O11, and Ln2O3 (Ln = La, Nd to Gd) in air atmosphere, while in N2 atmosphere the mass loss is still being observed up to 1000 C. The results also provided information concerning the gaseous products evolved during the thermal decomposition in dynamic dry air and nitrogen atmospheres.
A comparison of harvesting and drying methodologies on fatty acids composition of the green microalga Scenedesmus obliquus
(2020) Oliveira, Carlos Yure Barbosa de; Lopes, Rafael Garcia; Cella, Herculano; Menezes, Rafael Silva; Soares, Aline Terra; Antoniosi Filho, Nelson Roberto; Derner, Roberto Bianchini; Freitas, Thayna Lye Viegas
Harvesting and drying processes are still obstacles in the microalgae production chain. In this study, a combination of different harvesting and drying methods for Scenedesmus obliquus was proposed. S. obliquus was cultivated in a pond raceway for 15 days until reaching stationary phase. The culture was separated by different harvesting methods (centrifugation and flocculation) and drying methods (freezing, freeze-drying and oven drying), each combination in triplicate. Flocculation did not influence FAME yield of S. obliquus, except when the biomass was dried in an oven. The biomass that was only frozen had the lowest FAME content due to the presence of reactive water in the biomass. In contrast, frozen biomass had higher content of saturated and monosaturated fatty acids; freeze-drying or oven drying caused an enrichment of the polyunsaturated fatty acids content. In conclusion, if the biomass will be used to extract polyunsaturated fatty acids, freeze-drying would be more appropriate. On the other hand, if the purpose of the biomass is to produce biodiesel, the best process would be to just freeze the biomass.

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