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1.
Chemosphere ; 256: 127118, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32460162

RESUMO

Dye wastewater is harmful to the ecological environment because of its potential biological toxicity, teratogenicity, carcinogenicity, and mutagenicity. We fabricated a layered graphene oxide (GO) membrane through layer-by-layer (LBL) self-assembly. We used borate to crosslink with GO on a polyethyleneimine (PEI)-coated hydrolyzed polyacrylonitrile (hPAN) support. Fourier transform infrared (FTIR) spectrometry, Raman spectra, and x-ray photoelectron spectroscopy (XPS) confirmed the presence of a crosslinking reaction. The dynamic thermomechanical analysis (DMA) results indicated that the introduction of borate can significantly improve the mechanical properties of the membrane. The Young's modulus, ultimate tensile strength, and proportional limit of borate that was assembled twice as the outermost layer were increased by 110.81%, 62.37%, and 53.72%, respectively, as compared to those of a single-layered GO membrane. Moreover, the pure water fluxes of the layered GO membrane did not obviously decrease with an increase in the number of layers. The flux of the membrane with an outermost layer of borate was greater than that of the previous GO layer. The salt and dye rejection of the membranes was augmented with an increase in the number of layers. For the GO membrane assembled three times, rejection to methyl orange (MO), methylene blue (MB), NaCl, MgCl2, and MgSO4 reached 74.02%, 88.56%, 14.55%, 27.50%, and 41.95%, respectively. The use of borate as an inorganic crosslinker can avoid the environmental pollution caused by organic agents, and improve the mechanical properties as well as the filter capability of the layered GO membrane. Therefore, this study presents a novel method of membrane preparation for dye removal.


Assuntos
Compostos Azo/análise , Boratos/química , Grafite/química , Membranas Artificiais , Azul de Metileno/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Resinas Acrílicas/química , Filtração , Polietilenoimina/química , Propriedades de Superfície , Águas Residuárias/química
2.
Plant Physiol Biochem ; 151: 673-680, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32353673

RESUMO

This study was carried out to evaluate the effects of foliar sprays containing boron (B) nano-fertilizer (NF) on the growth and physiology of lettuce (Lactuca sativa) and zucchini (Cucurbita pepo). Plants were grown under greenhouse conditions for 60 days on a modified Hoagland solution with the presence and absence of boron (+B or -B). A synthesized B-NF foliar spray and a commercial B foliar fertilizer (Bortrac™ 150, BT) was applied at a concentration of 30 mg B L-1 at 10-d intervals throughout the experiment. The B-NF treatment increased the growth of lettuce 2.7- and 1.9-fold for shoots and roots, respectively, with an average production of lettuce biomass by ~58%. Similarly, the NF increased the growth of zucchini by 18 and 66% compared with Control-B (the absence of B), and 13 and 36% compared with BT, both for shoots and roots, respectively. Nevertheless, NF + B mostly decreased lettuce growth with symptoms of B toxicity in leaves. In lettuce, addition of B did not affect concentrations of phenols; however, in zucchini, Control-B induced a higher production of phenolic compounds possibly related to B deficiency. The B addition in lettuce reduced the DPPH activity by 32 and 21% in NF and BT, respectively, compared to Control-B. These responses were similar in zucchini; however, the effect of B was product of its presence in mineral solution rather than due the foliar product applied. This suggests that a NF-based delivery system for B may be highly effective at boosting plant productivity on B-limited soils.


Assuntos
Boratos , Compostos de Cálcio , Cucurbita , Fertilizantes , Alface , Nanopartículas , Boratos/química , Compostos de Cálcio/química , Cucurbita/metabolismo , Alface/metabolismo , Nanopartículas/química , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo
3.
Chemosphere ; 249: 126119, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32044610

RESUMO

The addition of different functional groups to ionic liquid anions or cations to synthesize task-specific ionic liquids (TSILs) according to specific needs has become a research hotspot. However, there are few studies on the toxicity of TSILs. We selected zebrafish (Danio rerio) to assess the toxicity of three TSILs 1-aminoethyl-3-methylimidazolium tetrafluoroborate ([C2NH2MIm]BF4), 1-methoxyethyl-3-methylimidazolium tetrafluoroborate ([MOEMIm]BF4) and 1-hydroxyethyl-3-methylimidazolium tetrafluoroborate ([HOEMIm]BF4). The 96 h median lethal concentration (96 h LC50) of the three TSILs [C2NH2MIm]BF4, [MOEMIm]BF4 and [HOEMIm]BF4 on zebrafish determined by an acute toxicity test were 143.8 mg/L, 2492.5 mg/L and 3086.7 mg/L, respectively. In the oxidative damage and DNA damage research experiments, zebrafish were exposed to [C2NH2MIm]BF4 (0, 5, 10, 20 and 40 mg/L), [MOEMIm]BF4 and [HOEMIm]BF4 (0, 1, 10, 50 and 100 mg/L) for 28 days, and levels of reactive oxygen species (ROS), superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), malondialdehyde (MDA) and olive tail moment (OTM) in zebrafish liver were tested on days 7, 14, 21 and 28 after the exposure test. During the experiment, increased contents of ROS and MDA were detected; enzymatic activities especially SOD were inhibited; and DNA damage occurred in zebrafish. The toxicity of the three TSILs was compared by the integrated biomarker response (IBR). The toxicity order of three TSILs was: [MOEMIm]BF4 > [HOEMIm]BF4 > [C2NH2MIm]BF4. In addition, this study can provide a toxicological basis for application research and the evaluation of functionalized ionic liquids with low toxicity in the future.


Assuntos
Líquidos Iônicos/toxicidade , Testes de Toxicidade Aguda , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/fisiologia , Animais , Ânions , Boratos , Catalase/metabolismo , Dano ao DNA , Glutationa Transferase/metabolismo , Fígado/metabolismo , Malondialdeído/metabolismo , Estresse Oxidativo/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/metabolismo , Peixe-Zebra/metabolismo
4.
PLoS One ; 15(2): e0229085, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32084174

RESUMO

The sodium iodide symporter (NIS) transports iodide, which is necessary for thyroid hormone production. NIS also transports other monovalent anions such as tetrafluoroborate (BF4-), pertechnetate (TcO4-), and thiocyanate (SCN-), and is competitively inhibited by perchlorate (ClO4-). However, the mechanisms of substrate selectivity and inhibitor sensitivity are poorly understood. Here, a comparative approach was taken to determine whether naturally evolved NIS proteins exhibit variability in their substrate transport properties. The NIS proteins of thirteen animal species were initially assessed, and three species from environments with differing iodide availability, freshwater species Danio rerio (zebrafish), saltwater species Balaenoptera acutorostrata scammoni (minke whale), and non-aquatic mammalian species Homo sapiens (human) were studied in detail. NIS genes from each of these species were lentivirally transduced into HeLa cells, which were then characterized using radioisotope uptake assays, 125I- competitive substrate uptake assays, and kinetic assays. Homology models of human, minke whale and zebrafish NIS were used to evaluate sequence-dependent impact on the organization of Na+ and I- binding pockets. Whereas each of the three proteins that were analyzed in detail concentrated iodide to a similar degree, their sensitivity to perchlorate inhibition varied significantly: minke whale NIS was the least impacted by perchlorate inhibition (IC50 = 4.599 µM), zebrafish NIS was highly sensitive (IC50 = 0.081 µM), and human NIS showed intermediate sensitivity (IC50 = 1.566 µM). Further studies with fifteen additional substrates and inhibitors revealed similar patterns of iodide uptake inhibition, though the degree of 125I- uptake inhibition varied with each compound. Kinetic analysis revealed whale NIS had the lowest Km-I and the highest Vmax-I. Conversely, zebrafish NIS had the highest Km and lowest Vmax. Again, human NIS was intermediate. Molecular modeling revealed a high degree of conservation in the putative ion binding pockets of NIS proteins from different species, which suggests the residues responsible for the observed differences in substrate selectivity lie elsewhere in the protein. Ongoing studies are focusing on residues in the extracellular loops of NIS as determinants of anion specificity. These data demonstrate significant transport differences between the NIS proteins of different species, which may be influenced by the unique physiological needs of each organism. Our results also identify naturally-existing NIS proteins with significant variability in substrate transport kinetics and inhibitor sensitivity, which suggest that the affinity and selectivity of NIS for certain substrates can be altered for biotechnological and clinical applications. Further examination of interspecies differences may improve understanding of the substrate transport mechanism.


Assuntos
Boratos/metabolismo , Animais , Linhagem Celular , Células HeLa , Humanos , Cinética , Lentivirus/genética , Percloratos/metabolismo , Simportadores/metabolismo , Tiocianatos/metabolismo , Baleias , Peixe-Zebra
5.
Macromol Rapid Commun ; 41(6): e1900636, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32022395

RESUMO

Preparation and low voltage induced bending (converse flexoelectricity) of crosslinked poly(ethylene glycol) diacrylate (PEGDA), modified with thiosiloxane (TS) and ionic liquid (1-hexyl-3-methylimidazolium hexafluorophosphate) (IL) are reported. In between 2µm PEDOT:PSS electrodes at 1 V, it provides durable (95% retention under 5000 cycles) and relatively fast (2 s switching time) actuation with the second largest strain observed so far in ionic electro-active polymers (iEAPs). In between 40 nm gold electrodes under 8 V DC voltage, the film can be completely curled up (270° bending angle) with 6% strain that, to the best of the knowledge, is unpreceded among iEAPs. These results render great potential for the TS/PEGDA/IL based electro-active actuators for soft robotic applications.


Assuntos
Elastômeros/química , Polietilenoglicóis/química , Boratos/química , Elastômeros/síntese química , Eletrodos , Ouro/química , Imidazóis/química , Líquidos Iônicos/química , Íons/química , Robótica/instrumentação , Robótica/métodos , Materiais Inteligentes/química
6.
Ecotoxicol Environ Saf ; 190: 110137, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31901815

RESUMO

Ionic liquids (ILs) are acknowledged as green chemicals and favorable substitutes for volatile organic solvents, which are currently used. However, previous studies have shown that these compounds had toxicological impacts on aquatic organisms. To investigate the effects of 1-hexyl-3- methylimidazolium bromide ionic liquid ([C6mim]Br) on embryonic development and reproduction in water flea (Daphnia magna), a series of exposure experiments were conducted, including acute toxicity, maternal exposure, and chronic exposure tests. In acute toxicity experiment, D. magna neonates exhibited developmental abnormalities in the shell spine and the second antennae in a concentration-dependent manner after exposure to [C6mim]Br. The results in maternal exposure test also revealed a certain embryo-toxicity in response to [C6mim]Br in D. magna. However, the toxicity was lower than that conveyed by direct acute exposure, this indicated that the IL could act directly on organism. During the 21 days chronic exposure, the 1.6 mg/L exposure caused marked drop in the survival, molts and the number of the first brood of D. magna. Meanwhile, the total number of offspring was significantly declined in 1.6 mg/L concentration treatment groups, whereas increased in 0.2 mg/L groups. Generally, abnormalities in the offspring were significantly increased across all of the treatment groups in contrast to the control. No effect on sex differentiation was found during the experiments. These findings suggested that [C6mim]Br could affect embryonic development and reproduction in D. magna, and provided references for further study on the mechanisms underlying toxicological effects of ILs and the assessment of their potential environmental risks.


Assuntos
Boratos/toxicidade , Daphnia/fisiologia , Imidazóis/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Organismos Aquáticos , Brometos/farmacologia , Daphnia/efeitos dos fármacos , Daphnia/embriologia , Embrião não Mamífero/efeitos dos fármacos , Desenvolvimento Embrionário , Feminino , Humanos , Líquidos Iônicos/toxicidade , Muda , Reprodução/efeitos dos fármacos , Solventes
7.
J Plant Res ; 133(2): 271-277, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31897741

RESUMO

Studies of plant-silicon (Si) interaction benefit from safe, affordable and accurate methods to measure acid-insoluble silica (phytoliths) for a large number of plant samples. This study aimed to evaluate the comparability between two chemical methods to dissolve leaf silica, borate fusion and 1% sodium carbonate (Na2CO3) extraction, in combination of two detection methods (ICP, molybdenum-blue colorimetry).We compared the results obtained by these methods, using dried leaf samples of five tropical tree species that differ widely in Si concentrations (4 to 100 mg g DW-1). Leaf Si concentration values determined after the two extraction methods were highly correlated (y = 0.79x, R2 = 0.998). However, compared to the extraction with borate fusion, the 1% Na2CO3 method resulted in lower Si concentration per unit dry mass by 16% to 32% (mean of 24.2%). We also found that molybdenum-blue colorimetry method may interfere with certain extraction methods. A simple equation can be used to correct for systematic underestimation of Si contents determined after extraction with 1% Na2CO3, which is the least expensive and safest among commonly used methods for extraction of Si from land plants.


Assuntos
Boratos , Carbonatos , Fracionamento Químico/métodos , Plantas/química , Silício/análise
8.
Chemistry ; 26(10): 2211-2221, 2020 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-31560142

RESUMO

The synthesis, characterization and biological activity of molybdenum(IV) complexes containing Trofimenko's scorpionato ligand, hydrotris(3-isopropylpyrazolyl)borate (TpiPr ), in addition to varying biologically active as well as other conventional ligands is described. Ligands employed include (O,O-) (S,O-) (N,N-) donors that have been successfully coordinated to the molybdenum center by means of oxygen-atom transfer (OAT) reactions from the known MoVI starting material, TpiPr MoO2 Cl. The synthesized complexes were characterized by standard analytical methods and where possible by X-ray diffraction analysis. The aqueous stability of the compounds was studied by means of UV/Vis spectroscopy and the impact of the attached ligand scaffolds on the oxidation potentials (MoIV to MoV ) was studied by cyclic voltammetry. Utilizing polyvinylpyrrolidone (PVP) as a solubilizing agent, adequate aqueous solubility for biological tests was obtained. Anticancer activity tests and preliminary mode of action studies have been performed in vitro and in vivo.


Assuntos
Antineoplásicos/química , Boratos/química , Complexos de Coordenação/química , Molibdênio/química , Pirazóis/química , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Quelantes/química , Complexos de Coordenação/farmacologia , Complexos de Coordenação/uso terapêutico , Cristalografia por Raios X , Ensaios de Seleção de Medicamentos Antitumorais , Estabilidade de Medicamentos , Humanos , Ligantes , Camundongos , Camundongos Endogâmicos BALB C , Conformação Molecular , Neoplasias/tratamento farmacológico , Nitrogênio/química , Oxigênio/química , Enxofre/química
9.
Macromol Rapid Commun ; 41(2): e1900450, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31778252

RESUMO

The latest generation of wearable devices features materials that are flexible, conductive, and stretchable, thus meeting the requirements of stability and reliability. However, the metal conductors that are currently used in various equipments cannot achieve these high performance expectations. Hence, a mussel-inspired conductive hydrogel (HAC-B-PAM) is prepared with a facile approach by employing polyacrylamide (PAM), dopamine-functionalized hyaluronic acid (HAC), borax as a dynamic cross-linker agent, and Li+ and Na+ as conductive ions. HAC-B-PAM hydrogels demonstrate an excellent stretchability (up to 2800%), high tensile toughness (42.4 kPa), self-adhesive properties (adhesion strength to porcine skin of 49.6 kPa), and good self-healing properties without any stimuli at room temperature. Furthermore, the fabricated hydrogel-based strain sensor is sensitive to deformation and can detect human body motion. Multifunctional hydrogels can be assembled into flexible wearable devices with potential applications in the field of electronic skin and soft robotics.


Assuntos
Adesivos/química , Bivalves/química , Hidrogéis/química , Dispositivos Eletrônicos Vestíveis , Resinas Acrílicas/química , Animais , Técnicas Biossensoriais , Boratos/química , Dopamina/química , Elasticidade , Condutividade Elétrica , Humanos , Ácido Hialurônico/química , Íons/química , Movimento (Física) , Resistência ao Cisalhamento
10.
Chemosphere ; 240: 124919, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31726585

RESUMO

Ionic liquids (ILs) are regarded as green solvents and are frequently used in the chemical industry. However, ILs may impact plant growth if they are present in the soil environment. To compare toxicity of ILs with different anions in soil, three imidazolium-based ionic liquids (1-hexyl-3-methylimidazolium bromide, 1-hexyl-3-methylimidazolium nitrate, 1-hexyl-3-methylimidazolium tetrafluoroborate) were used to assess impact on Vicia faba. Following 10 d of exposure to these three ILs from 0 to 2500 mg kg-1, shoot length, root length and dry weight of Vicia faba were determined. Pot trials revealed that ILs inhibited Vicia faba growth and according to EC50 values, [C6mim]BF4 was the most toxic one. In addition, physiological indicators of Vicia faba were determined following 10 d of exposure at selected IL concentrations (0, 1, 10, 100 and 500 mg kg-1). ILs led to the generation of reactive oxygen species and then caused oxidative damage, including lipid peroxidation, protein damage and DNA damage, which triggered an increase in antioxidant content and enzyme activity. The experimental results indicated that oxidative stress may be the primary underlying toxic mechanism for Vicia faba. Furthermore, based on the data of physiological experiment, integrated biomarker response (IBR) was calculated to compare the toxicity of the three ILs and toxic order was: [C6mim]NO3<[C6mim]Br<[C6mim]BF4.


Assuntos
Líquidos Iônicos/toxicidade , Vicia faba/efeitos dos fármacos , Ânions/química , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Boratos/toxicidade , Brometos , Dano ao DNA , Imidazóis/toxicidade , Peroxidação de Lipídeos , Nitratos/metabolismo , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo , Plântula/metabolismo , Solo/química , Poluentes do Solo/metabolismo , Solventes/metabolismo , Testes de Toxicidade , Vicia faba/crescimento & desenvolvimento
11.
Chemosphere ; 238: 124687, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31524622

RESUMO

The development of highly efficient and green catalytic oxidation process based on peroxymonosulfate (PMS) activation has been identified to be a significant yet challenging objective in the environmental catalysis field. A simple, environmentally benign and highly effective catalytic oxidation system was innovatively constructed by coupling NaBO2 and PMS for the removal of Acid Red 1. The catalytic mechanism in the NaBO2/PMS system was elucidated by electron paramagnetic resonance (EPR) combined with several radical capture reagents (ascorbic acid, methanol, tert-butyl alcohol, ethanol and l-histidine). The experimental results indicated that singlet oxygen (1O2) severed as the predominant reactive oxygen species (ROS) rather than the HO or during the catalytic oxidation process, at variance with the reported radical pathway in the Co2+/PMS system. Inspiringly, p-benzoquinone (p-BQ) as a trapping agent in most advanced oxidation process could be turned into the positive one in the NaBO2/PMS system, achieving a nearly 3-times enhancement in terms of the rate constant for AR1 removal. More interestingly, sodium chloride (NaCl) presented the same enhancement effect as p-benzoquinone due to generation of hypochlorous acid (HOCl) and more 1O2, which was completely different from the reported. This study develops a highly efficient green oxidation process and opens up a new insight in the remediation of contaminated water.


Assuntos
Boratos/química , Oxirredução , Peróxidos/química , Rodaminas/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Catálise , Oxigênio Singlete/metabolismo
12.
Carbohydr Polym ; 227: 115360, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31590866

RESUMO

Some applications, in particular, wound dressings, require significant water holding capability: hydrogels formed from Basil seed mucilage (BSM) are non-toxic natural substances and exhibit the needed water holding capacity. However, the sponges have low dimensional stability and easily degrade in aqueous media. We overcame this drawback by crosslinking with borax. To provide antibacterial activity, zinc oxide nanoparticles (ZnO-NP) were added. With 10-20 wt% added borax and ZnO-NP, all key properties improved: dimensional stability, water retention capacity (31 to 41%), stress at maximum load (2.6 to 6.6 MPa), Young's modulus (74 to 113 MPa) and strain (28 to 54%). An interconnecting system of pores with well distributed ZnO-NP was observed from scanning electron microscope. In addition, higher borax and ZnO-NP loadings slightly decreased porosity (92% to 73%) and swelling (109 to 56). Moreover, antibacterial activity and cytotoxicity of BSM hydrogel sponge were also examined.


Assuntos
Antibacterianos/química , Bandagens , Boratos/química , Sistemas de Liberação de Medicamentos , Nanocompostos/química , Mucilagem Vegetal/química , Óxido de Zinco/química , Linhagem Celular , Sobrevivência Celular , Escherichia coli/crescimento & desenvolvimento , Humanos , Ocimum basilicum , Sementes , Staphylococcus aureus/crescimento & desenvolvimento
13.
Chem Commun (Camb) ; 56(5): 723-726, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31840690

RESUMO

A new prosthetic group is reported for 18F-labelling of peptides and proteins based on the chemoselective ligation of potassium acyltrifluoroborates (KATs) and hydroxylamines without any detectable 18F/19F isotope exchange at the acyltrifluoroborate moiety. The new building block is appended via a common amide bond at room temperature with no need for protecting groups which enables an effective orthogonal 18F-radiolabelling.


Assuntos
Boratos/química , Radioisótopos de Flúor/química , Marcação por Isótopo/métodos , Peptídeos/química , Proteínas/química , Piridinas/química , Animais , Indicadores e Reagentes/química , Masculino , Camundongos Endogâmicos C57BL , Peptídeos/metabolismo , Tomografia por Emissão de Pósitrons/métodos , Proteínas/metabolismo , Compostos Radiofarmacêuticos/química , Temperatura
14.
Mater Sci Eng C Mater Biol Appl ; 107: 110351, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31761236

RESUMO

A titanium-containing borate glass series based on the system (52-X) B2O3-12CaO-6P2O5-14Na2O-16ZnO-XTiO2 with X varying from 0, 5 and 15 mol% of TiO2 incorporated, identified as BRT0, BRT1 and BRT3, respectively, were used in this study. Scaffolds (pore sizes, 165-230 µm and porosity, 53.51-69.51%) were prepared using a polymer foam replication technique. BRT3 scaffolds exhibited higher compressive strength (7.16 ±â€¯0.22 MPa) when compared to BRT0 (6.02 ±â€¯0.47 MPa) and BRT1 (5.65 ±â€¯0.28 MPa) scaffolds with lower, or no, TiO2 content. The solubility of the scaffolds decreased as the TiO2 content increased up to 15 mol% when samples of each scaffold were immersed in DI water and the pH of all these extracts went up from 7.0 to 8.5 in 30 days. The cumulative ion release from the scaffolds showed significant difference with respect to TiO2 content; addition of 5 mol% TiO2 at the expense of borate (B2O3) decreased the ion release remarkably. Furthermore, it was found that for all three scaffolds, cumulative ion release increased with incubation time. The results indicate that the degradation rates and compressive strengths of borate bioactive glass scaffolds could be controlled by varying the amount of TiO2 incorporated, confirming their potential as scaffolds in TKA and rTKA.


Assuntos
Boratos/química , Tecidos Suporte/química , Titânio/química , Artroplastia do Joelho , Osso Esponjoso/ultraestrutura , Força Compressiva , Módulo de Elasticidade , Vidro/química , Humanos , Concentração de Íons de Hidrogênio , Íons/farmacocinética , Teste de Materiais , Microscopia Eletrônica de Varredura , Poliuretanos/química , Porosidade , Solubilidade
15.
Molecules ; 25(1)2019 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-31877919

RESUMO

The synthesis of a number of pentaborate(1-) salts from cations arising from N-substituted α,α-, α,ß-, and α,γ-diaminoalkanes has been attempted in aqueous solution from B(OH)3 and the appropriate diammine in a 10:1 ratio. Despite relatively mild work-up conditions the pentaborate(1-) salts prepared were not always as anticipated and the following compounds were isolated in good yield: [Me2NH(CH2)2NHMe2][B5O6(OH)4]2 (1), [Et2NH(CH2)2NHEt2][B5O6(OH)4]2 (2), [Et2NH2][B5O6(OH)4] (3), [Me2NH2][B5O6(OH)4] (4), [Me2NH(CH2)3NHMe2][B5O6(OH)4]2 (5), [Et2NH(CH2)3NHEt2][B5O6(OH)4]2 (6), [Me3NCH2CH=CH2][B5O6(OH)4] (7), and [Me3N(CH2)3NMe3] [B5O6(OH)4]2.0.5H2O (8). The tetraborate(2-) salt, [Me3N(CH2)2NMe3][B4O5(OH)4].2B(OH)3.2H2O (9) was obtained in moderate yield (41%) from a 3:1 reaction of B(OH)3 with [Me3N(CH2)2NMe3](OH)2. All compounds were characterized by spectroscopy (1H, 11B, 13C NMR and IR) and thermal gravimetric analysis (TGA). BET analysis on materials derived thermally from selected samples (1, 2, 6, 7) all had porosities of < 1 m2/g, demonstrating that they were non-porous. Single-crystal XRD structures were obtained for 2, 3, 7, 8 and 9 and all contain extensive H-bonded polyborate lattices.


Assuntos
Compostos de Amônio/química , Boratos/química , Sais/química , Cátions/química , Ligação de Hidrogênio , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Cloreto de Sódio/química , Água/química
16.
J Contemp Dent Pract ; 20(10): 1141-1145, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31883247

RESUMO

AIM: To determine the knowledge and attitude of dental practitioners (DPs) for internal bleaching technique (IBT) in Kingdom of Saudi Arabia. MATERIALS AND METHODS: A cross-sectional study was developed based on a convenient sampling of dental practitioners and specialists working in Kingdom of Saudi Arabia. DPs responded to a structured, self-administered questionnaire for evaluation of their knowledge and attitude toward IBT. The questionnaire had two components: (i) the characteristics of the study participants; and (ii) the items related to the internal bleaching technique (IBT). Data analysis was conducted using SPSS (version 25.0), with descriptive statistics and a bivariate analysis. RESULTS: A total of 532 dental practitioners (61.3% males and 38.7% females) participated in this study. The response rate of participation was estimated at 92.5%. Almost 37% participants considered the sodium perborate as the most commonly used dental material for internal bleaching. Almost 70% participants reported that superficial enamel discoloration was a contraindication for internal bleaching in endodontically treated teeth. CONCLUSION: DPs have good knowledge and attitude on use of IBT for discolored teeth. In general, there is a need to improve knowledge and attitude of dental professionals about the IBT by attending continuing dental educational programs. CLINICAL SIGNIFICANCE: Saving of the remaining tooth structure is a main principle of the different types of dental treatments. So the IBT should be known for all dental practitioners to use it before going to more aggressive dental treatment options such as full crowns. How to cite this article: Doumani M, Alotaibi AN, Al Hussain F, et al. Internal Bleaching of Endodontically Treated Teeth: A Dental Practitioner's Perspective from Kingdom of Saudi Arabia. J Contemp Dent Pract 2019;20(10):1141-1145.


Assuntos
Clareamento Dental , Descoloração de Dente , Dente não Vital , Boratos , Estudos Transversais , Feminino , Humanos , Peróxido de Hidrogênio , Masculino , Arábia Saudita
17.
Int J Mol Sci ; 20(21)2019 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-31717775

RESUMO

The joint toxicities of [BMIM]BF4, [BMIM]PF6, and [HMIM]BF4 on acetylcholinesterase (AChE) were systematically investigated by using a progressive approach from 1D single effect point, 2D concentration-response curve (CRC), to 3D equivalent-surface (ES) level. The equipartition equivalent-surface design (EESD) method was used to design 10 ternary mixtures, and the direct equipartition ray (EquRay) design was used to design 15 binary mixtures. The toxicities of ionic liquids (ILs) and their mixtures were determined using the microplate toxicity analysis (MTA) method. The concentration addition (CA), independent action (IA), and co-toxicity coefficient (CTC) were used as the additive reference model to analyze the toxic interaction of these mixtures. The results showed that the Weibull function fitted well the CRCs of the three ILs and their mixtures with the coefficient of determination (R2) greater than 0.99 and root-mean-square error (RMSE) less than 0.04. According to the CTC integrated with confidence interval (CI) method (CTCICI) developed in this study, the 25 mixtures were almost all additive action at 20% and 80% effect point levels. At 50% effect, at least half of the 25 mixtures were slightly synergistic action, and the remaining mixtures were additive action. Furthermore, the ESs and CRCs predicted by CA and IA were all within the CIs of mixture observed ESs and CRCs, respectively. Therefore, the toxic interactions of these 25 mixtures were actually additive action. The joint toxicity of the three ILs can be effectively evaluated by the ES method. We also studied the relationship between the mixture toxicities and component concentration proportions. This study can provide reference data for IL risk assessment of combined pollution.


Assuntos
Inibidores da Colinesterase/toxicidade , Líquidos Iônicos/toxicidade , Acetilcolinesterase/efeitos dos fármacos , Boratos/química , Boratos/toxicidade , Inibidores da Colinesterase/química , Sinergismo Farmacológico , Imidazóis/química , Imidazóis/toxicidade , Concentração Inibidora 50 , Líquidos Iônicos/química , Cinética , Modelos Químicos , Testes de Toxicidade
18.
Environ Sci Technol ; 53(24): 14620-14629, 2019 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-31738055

RESUMO

Boron is a finite resource, which has been listed as a critical raw material in the EU since 2014. Glass, frits and ceramics production, as well as fertilizers are among the major uses of B. Moreover, about 50 000 t B have been applied as fire retardant and pest repellent in cellulose fiber insulation (CFI) in Europe since the 1980s. Here we propose the end-of-life utilization of borated CFI as B fertilizer, to decrease societal B consumption and to avoid costly and potentially environmentally harmful CFI incineration and deposition in landfills. In a case study, we show that CFI biochar can provide substantial amounts of B to rapeseed and sunflower, with the B plant-availability being comparable to sodium tetraborate, a conventional B fertilizer. The annual B fertilizer consumption of the EU is estimated at ∼4000 t B yr-1, which could be sustained by the B currently installed as CFI for >10 years. In addition, the annual use of B in CFI of 1100 t B yr-1 could cover ∼25% of the annual B fertilizer demand of the EU. Hence, conversion of CFI to B fertilizer provides a meaningful end-of-life strategy, which would contribute to a more resource-efficient and sustainable economy and to several of the UN Sustainable Development Goals.


Assuntos
Boratos , Fertilizantes , Europa (Continente) , Incineração , Reciclagem
19.
Environ Pollut ; 255(Pt 2): 113321, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31610515

RESUMO

Ionic liquids (ILs) are extensively used in several chemistry fields. And research about the effects of ILs on soil microbes is needed. In this study, brown soil was exposed to 1-butyl-3-methylimidazolium bromide ([C4mim]Br), 1-hexyl-3-methylimidazolium bromide ([C6mim]Br) and 1-decyl-3-methylimidazolium bromide ([C10mim]Br). The toxicities of the three ILs are evaluated by measuring the soil culturable microbial number, enzyme activity, microbial diversity and, abundance of the ammonia monooxygenase (amoA) genes of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). Results showed that all tested ILs caused a decrease in culturable microbial abundance. Tested ILs exposure inhibit urease activity and promote acid phosphatase and ß-glucosidase activities. Tested ILs reduced soil microbial diversity and the abundances of AOB-amoA and AOA-amoA genes significantly. After a comparison of the integrated biomarker response (IBR) index, the toxicities of tested ILs to soil microorganisms were as follows: [C10mim]Br > [C6mim]Br > [C4mim]Br. Among all collected biomarkers, the abundance of the AOA-amoA gene was the most sensitive one and was easily affected after ILs exposure.


Assuntos
Archaea/efeitos dos fármacos , Bactérias/efeitos dos fármacos , Boratos/toxicidade , Brometos/toxicidade , Imidazóis/toxicidade , Líquidos Iônicos/toxicidade , Fosfatase Ácida/metabolismo , Amônia/metabolismo , Glucosidases/metabolismo , Oxirredução , Oxirredutases/genética , Filogenia , Solo/química , Microbiologia do Solo , Urease/antagonistas & inibidores
20.
Inorg Chem ; 58(19): 12843-12853, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31502453

RESUMO

A series of five compounds TpMesMFla (TpMes = hydrotris(3-mesityl)pyrazolylborate; M = Mn, Fe, Co, Ni, Zn; Fla = 3-hydroxyflavonolate) has been synthesized as models for the 2,4-quercetin dioxygenase, QueD. The structures have been determined and the complexes proved to be isomorphous. Considering the structures more closely revealed that they differ in the degree of delocalization in the chelate ring formed through the binding of the two O donors of the flavonolate to the metal center, which is also supported by the results of UV-vis and IR spectroscopic investigations. The resulting trend (Zn/Fe > Co > Mn > Ni) is, however, not in line with the one that was found investigating the redox properties of the complexes by cyclic voltammetry (Zn > Fe > Ni > Co > Mn). Notably, from CV clear-cut information could be derived, as the complexes exhibited exceptionally well-behaved quasi-reversible redox transitions, indicating that the Tp ligand stabilizes the flavonolate radical formed in the oxidation process rather well. The fact that the rates, with which the complexes react with O2 in DMF solution, correlate with the position of the flavonolate redox couples, suggest that these reactions proceed via the initial electron transfer from the flavonolate to O2. After the O2 reaction, salicylic acid was identified as one of the products, the formation of which can be explained by the hydrolysis of the depside that should form upon a dioxygenation similar to the QueD enzyme-catalyzed reaction. 18O labeling experiments confirmed the presence of O2 derived O atoms. Mechanistic inferences based on the above results are discussed.


Assuntos
Bactérias/enzimologia , Complexos de Coordenação/química , Dioxigenases/química , Flavonóis/química , Pirazóis/química , Bactérias/química , Materiais Biomiméticos/química , Boratos/química , Catálise , Cristalografia por Raios X , Ligantes , Modelos Moleculares
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