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1.
J Chromatogr A ; 1626: 461365, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797844

RESUMO

Sequential injection chromatography (SIC) is an alternative for fast chromatographic separations with low consumption of organic solvents. However, its separation capacity is restricted by the use of short chromatographic columns and the limitations for gradient elution. The present work aimed to expand the analytical capacity of SIC by exploiting a multidimensional approach with two chromatographic columns, different in their separation mechanisms, which increased the selectivity and peak resolution. The viability of the proposal was demonstrated by separation of aromatic biogenic amines (histamine, tyramine, phenylethylamine, and tryptamine), whose unidimensional separation was not achieved either by using cyanopropyl or C18 chromatographic columns. In the two-dimensional approach, the fraction of the eluate unresolved in the first dimension (containing tyramine and phenylethylamine) was collected in a sampling loop and, subsequently, inserted in the second chromatographic dimension (heart-cutting mode). Under the optimized conditions, the first chromatographic dimension was based on a cyanopropyl monolithic column and an aqueous mobile phase composed of phosphoric acid solution, pH 2.5, while the second dimension employed a C18 superficially porous particle column and a mobile phase composed of acetonitrile and phosphoric acid aqueous solution, pH 2.5 (7:93, v/v). The total analysis time was 8 min, and a resolution of 1.72 was achieved between the nearest peaks (tyramine and phenylethylamine). Linear responses were obtained within 10 and 50 mg L-1 (r > 0.997), with detection limits estimated at 2.7, 7.7, 1.9, and 0.3 mg L-1, for histamine, tyramine, phenylethylamine, and tryptamine, respectively, and a coefficient of variation of 3.0% (n = 12).


Assuntos
Cromatografia/métodos , Acetonitrilos/química , Aminas Biogênicas/isolamento & purificação , Ácidos Fosfóricos/química , Solventes/química
2.
Chemosphere ; 257: 127244, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32512335

RESUMO

The industrial waste streams with excess phosphorus acid (H3PO4) was generated in semiconductor industries that has extremely low pH rendering commercial adsorbents unfit for adsorption recycling of valuable materials. This study for the first time use covalent organic framework EB-COF:Br to adsorb phosphoric acid from extremely acidic H3PO4 solutions at pH ranging 0.86 to -0.65. The EB-COF:Br could maintain structural stability with these extremely acidic solutions. At 25 °C, 95% adsorption could be completed within 10 min of contact; while the adsorption capacities of EB-COF:Br from 75% H3PO4 solution ranged 6520‒6980 mg-H3PO4/g during 25-45 °C. The adsorption is regarded isoenthalpic with no heat effects. Water washing is efficient for H3PO4 desorption, and the washed COF can be reused as an efficient adsorbent under extremely acidic environment. The interactions between (‒N+=) and (‒CO) groups, and part of the (‒NH‒) groups participated in the adsorption process with adsorbed H3PO4 molecules. The adsorbed H3PO4 molecules then formed H-bonding to trap the excess free H3PO4 molecules to the internal cavity of the COF.


Assuntos
Ácidos Fosfóricos/química , Poluentes Químicos da Água/química , Adsorção , Resíduos Industriais , Estruturas Metalorgânicas , Água , Poluentes Químicos da Água/análise
3.
Food Chem ; 328: 127147, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32497897

RESUMO

The reduction of the 3-monochloropropane-1,2-diol esters (3-MCPDE) and glycidyl esters (GE) was successfully achieved by the optimization of four processing parameters: phosphoric acid dosage, degumming temperature, bleaching earth dosage, and deodorization temperature by response surface methodology without the need for additional processing steps. The optimized processing conditions were 0.31% phosphoric acid dosage, 50 °C degumming temperature, 3% bleaching earth dosage, and 240 °C deodorization temperature. The optimization resulted in more than 80% and 65% reduction of 3-MCPDE and GE levels, respectively with color and FFA contents maintained in the acceptable range specified by Palm Oil Refiners Association of Malaysia. The optimized refining condition was transferred to macro scale refining units of 1 kg and 3 kg capacities to investigate its successful application during scale-up process.


Assuntos
Indústria de Processamento de Alimentos/métodos , Óleo de Palmeira/química , alfa-Cloridrina/química , Cor , Compostos de Epóxi/química , Ésteres , Qualidade dos Alimentos , Laboratórios , Malásia , Ácidos Fosfóricos/química , Propanóis/química , Temperatura , alfa-Cloridrina/análise
4.
Artigo em Inglês | MEDLINE | ID: mdl-32361468

RESUMO

The present study aimed to evaluate the effect of the immobilization method of trypsin on biochar on the hydrolysis of casein from different sources, when compared to the process using trypsin in native form, to obtain bioactive peptides. The modification of the surface of biochar with glutaraldehyde was effective, as shown by the results of FTIR assay and the texture profile of the materials. Both activated and functionalized biochar showed high immobilization efficiency (greater than 87%) and high binding capacity (greater than 91 mg/g). During hydrolysis, the biocatalyst obtained by enzyme immobilization on the functionalized biochar presented a higher hydrolysis capacity for the different caseins when compared to the enzyme immobilized by adsorption, with values of 3.05 and 2.73 U/mg for goat casein, 2.36 and 1.85 U/mg for bovine casein, and 2.60 and 2.37 U/mg for buffalo, casein, respectively, with 60 min of reaction. The results of inhibitory activity in this study ranged from 93.5% and 25.5% for trypsin in its free form and immobilized on functionalized activated carbon, respectively, under the same reaction conditions. The immobilization methods were efficient, presenting high immobilization capacity. The proteolytic activity of trypsin immobilized via covalent binding was higher when compared the immobilization by adsorption. Thus, the functionalized biochar has proven to be potential support for enzyme immobilization, and the biocatalyst can be reused for more than 4 cycles. Despite lower ACE inhibition values of hydrolyzed obtained with the immobilized enzymes compared to free enzymes, biocatalysts present advantage due to the possibility of reuse.


Assuntos
Caseínas/química , Carvão Vegetal/química , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Tripsina/química , Tripsina/metabolismo , Adsorção , Animais , Biocatálise , Bovinos , Estabilidade Enzimática , Glutaral/química , Concentração de Íons de Hidrogênio , Hidrólise , Cinética , Ácidos Fosfóricos/química , Proteólise , Propriedades de Superfície , Temperatura
5.
Chemosphere ; 253: 126682, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32283426

RESUMO

The industry devoted to the production of phosphoric acid by using as raw material sedimentary phosphate rock (PR) is considered as a NORM activity (Naturally Occurring Radioactive Materials), due to the high levels of U-series radionuclides contained in this ore, which are 1-2 orders of magnitude higher than those in unperturbed soils. This fact allowed us to develop a deep characterization of the raw materials, wastes, main intermediate materials, and final products obtained at a typical phosphoric acid factory. The elemental composition (major, minor and trace elements), radionuclide concentrations, grain size distribution, mineralogy and micro-structural composition were analyzed. The aim of this characterization was to obtain information for operators and maintenance personnel involved in clean-up and waste management operations. The highest concentrations of some heavy metals and radionuclide activity concentrations were found in the "scales" (or internal incrustations)from the pipes that carry either phosphoric acid (PA) or the phosphogypsum waste (PG). The highest concentrations where found for 226Ra and 40K,with values up to 9 and 5 Bq g-1, respectively. In addition, high concentrations of many toxic heavy metals and trace elements, such as Cd, Cr, Ni, Sr, Y, V, Zn, Th, and U, were found in some sludge samples. The shielding effect of the containers/vessels/pipes has an essential role in the measured external dose in the intermediate products. The radiological implications of natural radionuclides with higher activity showed that if the maximum particulate matter concentration established in the Spanish regulation is verified, and taking into account the most conservative scenario, the annual limit of 1 mSv y-1 is not exceeded.


Assuntos
Indústria Química , Exposição Ocupacional/estatística & dados numéricos , Ácidos Fosfóricos/química , Exposição à Radiação/estatística & dados numéricos , Sulfato de Cálcio , Humanos , Metais Pesados , Fosfatos , Fósforo , Plantas , Radioisótopos/análise , Solo
6.
Ecotoxicol Environ Saf ; 196: 110550, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32247244

RESUMO

Iron/zinc (Fe/Zn), phosphoric acid (H3PO4) or in combination (Fe/Zn + H3PO4) modified sludge biochar (SBC) were prepared and tested in this study to adsorb fluoroquinolones antibiotics including ciprofloxacin (CIP), norfloxacin (NOR) and ofloxacin (OFL) from water. Fe/Zn + H3PO4-SBC had an increased surface area (SBET), total pore volume (Vtot), mesoporous volume (Vmes), pore diameter (Dp) and oxygen-containing functional groups. It exhibited superior adsorption performance for CIP, NOR and OFL with the maximum adsorption amount of 83.7, 39.3, 25.4 mg g-1, respectively. Pseudo-second kinetic and Freundlich isotherm model presented the better fitting. The results of models and characterization analysis in combination indicated that physisorption and chemisorption, including pore filling, hydrogen bonding, π-π interaction, electrostatic interaction and functional groups complexation on a heterogeneous surface were the dominant process and mechanism. Liquid film diffusion was the main rate-limiting step. The adsorption process of CIP, NOR and OFL onto Fe/Zn + H3PO4-SBC were a spontaneous endothermic process. This study demonstrated that Fe/Zn + H3PO4 modified SBC exhibited high adsorption capacity, which was a promising adsorbent for fluoroquinolones as well as for other antibiotics effective removal from waters.


Assuntos
Antibacterianos/análise , Carvão Vegetal/química , Fluoroquinolonas/análise , Esgotos/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Ferro/química , Cinética , Modelos Teóricos , Ácidos Fosfóricos/química , Propriedades de Superfície , Zinco/química
7.
Braz Oral Res ; 34: e018, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32187304

RESUMO

The objective of this study was to evaluate the influence of hydrofluoric acid (HF) concentration, etching time, and application of phosphoric acid (PA) followed by neutralization with sodium bicarbonate on the bond strength between a feldspar ceramic and resin cement. Thus, 80 blocks (10 x 12 x 2 mm) of glass ceramic (VM - Vita Mark II - Vita Zahnfabrik) were made and randomly assigned to eight groups (n = 10) according to the factors: HF concentration (5 and 10%), etching time (60 and 120 s), and use of phosphoric acid (PA) (with and without). According to the experimental group, 37% PA (Condac, FGM) was applied after HF etching for 60s. Afterwards, samples were immersed in sodium bicarbonate for 1 min then in an ultrasonic bath in distilled water (5 min) for cleaning. After surface bonding treatment, cylinders (Ø = 2 mm; h = 2 mm) of dual resin cement (AllCem / FGM) were made in the center of each block. The samples were then stored in water (37ºC) for 90 days and submitted to the shear bond test (50 KgF, 1 mm/min). Failure analysis was performed by stereomicroscope and scanning electron microscopy. Data (MPa) were analyzed with 3-way ANOVA and Tukey's test. Only the factor "HF concentration" was significant (p = 0.02). Most failures were of cohesive in ceramic (40%) and mixed types (42.5%). The 10% HF resulted in higher shear bond strength value than the 5% HF. Surface cleaning with phosphoric acid followed by sodium bicarbonate and HF time (60 or 120 seconds) did not influence the resin bond strength to feldspar ceramic.


Assuntos
Silicatos de Alumínio/química , Colagem Dentária/métodos , Ácido Fluorídrico/química , Ácidos Fosfóricos/química , Compostos de Potássio/química , Análise de Variância , Porcelana Dentária/química , Teste de Materiais , Metacrilatos/química , Microscopia Eletrônica de Varredura , Valores de Referência , Reprodutibilidade dos Testes , Cimentos de Resina/química , Resistência ao Cisalhamento/efeitos dos fármacos , Silanos/química , Propriedades de Superfície , Fatores de Tempo
8.
Proc Natl Acad Sci U S A ; 117(13): 7276-7283, 2020 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-32188786

RESUMO

All known polymerases copy genetic material by catalyzing phosphodiester bond formation. This highly conserved activity proceeds by a common mechanism, such that incorporated nucleoside analogs terminate chain elongation if the resulting primer strand lacks a terminal hydroxyl group. Even conservatively substituted 3'-amino nucleotides generally act as chain terminators, and no enzymatic pathway for their polymerization has yet been found. Although 3'-amino nucleotides can be chemically coupled to yield stable oligonucleotides containing N3'→P5' phosphoramidate (NP) bonds, no such internucleotide linkages are known to occur in nature. Here, we report that 3'-amino terminated primers are, in fact, slowly extended by the DNA polymerase from B. stearothermophilus in a template-directed manner. When its cofactor is Ca2+ rather than Mg2+, the reaction is fivefold faster, permitting multiple turnover NP bond formation to yield NP-DNA strands from the corresponding 3'-amino-2',3'-dideoxynucleoside 5'-triphosphates. A single active site mutation further enhances the rate of NP-DNA synthesis by an additional 21-fold. We show that DNA-dependent NP-DNA polymerase activity depends on conserved active site residues and propose a likely mechanism for this activity based on a series of crystal structures of bound complexes. Our results significantly broaden the catalytic scope of polymerase activity and suggest the feasibility of a genetic transition between native nucleic acids and NP-DNA.


Assuntos
Amidas/química , DNA Polimerase Dirigida por DNA/química , DNA/química , Ácidos Fosfóricos/química , Amidas/síntese química , Amidas/metabolismo , DNA/síntese química , DNA Polimerase Dirigida por DNA/metabolismo , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Conformação de Ácido Nucleico , Oligonucleotídeos/química , Ácidos Fosfóricos/síntese química , Ácidos Fosfóricos/metabolismo , Polimerização , RNA/química
9.
Nucleic Acids Res ; 48(6): 2853-2865, 2020 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-32103257

RESUMO

Spinal muscular atrophy (SMA) is a motor neuron disease. Nusinersen, a splice-switching antisense oligonucleotide (ASO), was the first approved drug to treat SMA. Based on prior preclinical studies, both 2'-O-methoxyethyl (MOE) with a phosphorothioate backbone and morpholino with a phosphorodiamidate backbone-with the same or extended target sequence as nusinersen-displayed efficient rescue of SMA mouse models. Here, we compared the therapeutic efficacy of these two modification chemistries in rescue of a severe mouse model using ASO10-29-a 2-nt longer version of nusinersen-via subcutaneous injection. Although both chemistries efficiently corrected SMN2 splicing in various tissues, restored motor function and improved the integrity of neuromuscular junctions, MOE-modified ASO10-29 (MOE10-29) was more efficacious than morpholino-modified ASO10-29 (PMO10-29) at the same molar dose, as seen by longer survival, greater body-weight gain and better preservation of motor neurons. Time-course analysis revealed that MOE10-29 had more persistent effects than PMO10-29. On the other hand, PMO10-29 appears to more readily cross an immature blood-brain barrier following systemic administration, showing more robust initial effects on SMN2 exon 7 inclusion, but less persistence in the central nervous system. We conclude that both modifications can be effective as splice-switching ASOs in the context of SMA and potentially other diseases, and discuss the advantages and disadvantages of each.


Assuntos
Amidas/química , Morfolinos/uso terapêutico , Atrofia Muscular Espinal/tratamento farmacológico , Oligonucleotídeos Antissenso/uso terapêutico , Ácidos Fosfóricos/química , Animais , Modelos Animais de Doenças , Éxons/genética , Humanos , Camundongos Transgênicos , Morfolinos/farmacologia , Atividade Motora/efeitos dos fármacos , Neurônios Motores/efeitos dos fármacos , Neurônios Motores/patologia , Músculos/patologia , Atrofia Muscular Espinal/patologia , Atrofia Muscular Espinal/fisiopatologia , Junção Neuromuscular/patologia , Junção Neuromuscular/fisiopatologia , Oligonucleotídeos Antissenso/farmacologia , Fenótipo , Processamento de RNA/efeitos dos fármacos , Processamento de RNA/genética , Medula Espinal/patologia , Proteína 2 de Sobrevivência do Neurônio Motor/genética , Resultado do Tratamento
10.
J Environ Sci (China) ; 90: 364-374, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32081332

RESUMO

The leaching concentrations of different metals in stainless steel pickling residue (SSPR) were determined and the toxic metals were treated using Na2S∙xH2O, FeSO4∙6H2O, and phosphoric acid. A modified European Community Bureau of Reference (BCR) sequential extraction was used to identify the speciation of the concerned metals. Results showed that SSPR contains a large amount of Ca (58.41%), Fe (29.44%), Cr (3.83%), Ni (2.94%), Mn (2.82%) and some of Al, Cu, Mg, Zn. Among them, Cr and Ni were the most toxic metals in SSPR, thus the raw SSPR falls into hazardous waste category due to the leaching amount of Cr. In addition, the leached Cr was identified as Cr6+ (MgCrO4) in the waste. BCR test revealed that risk assessment code (RAC) of Cr and Ni were 33.29% and 61.7%, indicating they posed "high" and "very high" risk to the environment, respectively. After fixing by Na2S∙xH2O and FeSO4∙6H2O, the leaching concentrations of Cr and Ni were less than 1.5 and 0.5 mg/L, respectively. After fixing by Na2S∙xH2O and FeSO4∙6H2O the treated SSPR can be safely reused as roadbed materials, concrete and cement aggregates. This study provides a useful implication in treatment and beneficial reuse of heavy metal-containing hazardous wastes.


Assuntos
Resíduos Perigosos/análise , Metais Pesados , Aço Inoxidável , Ácidos Fosfóricos/química
11.
Niger J Clin Pract ; 23(1): 18-25, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31929202

RESUMO

Aim: This study evaluated the microtensile bond strength (MTBS) of an orthodontic adhesive to water-aged composite surfaces using different surface treatments. Subjects and Methods: Twelve composite blocks (10 mm × 10 mm × 5 mm) were fabricated and randomly divided into two groups. Half of the specimens were stored in distilled water for 1 day, and the other specimens were stored for 30 days. The specimens were randomly assigned to six groups according to surface treatments (n = 15): Group 1, control (no treatment); Group 2, phosphoric acid; Group 3, diamond bur; Group 4, diamond bur + phosphoric acid; Group 5, laser; and Group 6, laser + phosphoric acid. One coat of orthodontic adhesive was bonded to one surface of composite blocks, and a microhybrid composite resin was bonded to the surfaces via a Teflon mold. Bond strength was evaluated using an MTBS test. Surface topography was evaluated using scanning electron microscopy (SEM) analysis. The data were analyzed using one-way analysis of variance, Tamhane post-hoc test, and independent sample t-tests (P < 0.05). Results: Bond strength values tended to decrease in all groups (with the exception of Group 2) after storage in water for 30 days (P < 0.05). Laser and diamond bur application (with or without phosphoric acid) enhanced the bond strength. Conclusions: An Er,Cr:YSGG laser application may be a feasible alternative to diamond bur for enhancing the bond strength of orthodontic adhesive to composite resin.


Assuntos
Resinas Compostas/química , Colagem Dentária , Cimentos Dentários/química , Lasers de Estado Sólido/uso terapêutico , Resistência à Tração , Água/química , Resinas Compostas/uso terapêutico , Análise do Estresse Dentário , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Ácidos Fosfóricos/química , Resistência ao Cisalhamento , Propriedades de Superfície
12.
J Enzyme Inhib Med Chem ; 35(1): 59-64, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31663383

RESUMO

A primary strategy to combat antimicrobial resistance is the identification of novel therapeutic targets and anti-infectives with alternative mechanisms of action. The inhibition of the metalloenzymes carbonic anhydrases (CAs, EC 4.2.1.1) from pathogens (bacteria, fungi, and protozoa) was shown to produce an impairment of the microorganism growth and virulence. As phosphonamidates have been recently validated as human α-CA inhibitors (CAIs) and no phosphorus-based zinc-binding group have been assessed to date against ß-class CAs, herein we report an inhibition study with this class of compounds against ß-CAs from pathogenic bacteria, fungi, and protozoa. Our data suggest that phosphonamidates are among the CAIs with the best selectivity for ß-class over human isozymes, making them interesting leads for the development of new anti-infectives.


Assuntos
Amidas/farmacologia , Anti-Infecciosos/farmacologia , Inibidores da Anidrase Carbônica/farmacologia , Anidrases Carbônicas/metabolismo , Compostos Organometálicos/farmacologia , Ácidos Fosfóricos/farmacologia , Amidas/química , Anti-Infecciosos/síntese química , Anti-Infecciosos/química , Bactérias/efeitos dos fármacos , Bactérias/enzimologia , Inibidores da Anidrase Carbônica/síntese química , Inibidores da Anidrase Carbônica/química , Relação Dose-Resposta a Droga , Fungos/efeitos dos fármacos , Fungos/enzimologia , Humanos , Leishmania donovani/efeitos dos fármacos , Leishmania donovani/enzimologia , Estrutura Molecular , Compostos Organometálicos/síntese química , Compostos Organometálicos/química , Ácidos Fosfóricos/química , Fósforo/química , Fósforo/farmacologia , Relação Estrutura-Atividade , Zinco/química , Zinco/farmacologia
13.
Ann Anat ; 227: 151431, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31634560

RESUMO

Histological analysis is a fundamental and principal method used in biological research and even for disease diagnosis. The result shows the status of cells and tissues in organs and enables us to infer the condition of the whole body. The tissue staining method known as hematoxylin and eosin staining (HE) is one of the most general methods of investigating the status of cells and tissues. Hematoxylin stains the nucleus violet and eosin stains cytosol pink. HE staining shows the unique morphologies of tissues and cells. However, after being stained with HE, tissues are very difficult to use in another histological analysis because hematoxylin is hard to remove from the sections due to its stain stability. Therefore, serial sections of the tissue are used to obtain more information through another staining, including immunohistochemistry. The adjacent tissue section is not the same as the HE-stained section, however, so the results from the adjacent sections can cause confusion or ambiguity. The present study showed that our decolorization solution can decolor the hematoxylin or iron hematoxylin stain from stained structures, including the nucleus, and the decolored section could be stained again in another staining, including immunohistochemistry. This decolorization method is very valuable, in that it can determine the accurate distribution of substances and features in cells and tissues, and thus it can improve the robustness of the resulting data.


Assuntos
Corantes/metabolismo , Corantes Fluorescentes/metabolismo , Animais , Compostos Azo/metabolismo , Ácidos Carboxílicos/química , Quelantes/química , Amarelo de Eosina-(YS)/metabolismo , Hematoxilina/metabolismo , Imuno-Histoquímica , Verde de Metila/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos ICR , Microscopia de Fluorescência , Ácidos Fosfóricos/química , Nitrato de Prata/metabolismo , Trometamina/química
15.
Int J Mol Sci ; 20(24)2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31835689

RESUMO

There is a current clinical need for the development of bone void fillers and bioactive bone graft substitutes. The use of mesenchymal stem cells (MSCs) that are seeded into 3D scaffolds and induce bone generation in the event of MSCs osteogenic differentiation is highly promising. Since calcium ions and phosphates promote the osteogenic differentiation of MSCs, the use of the calcium complexes of phosphate-containing polymers is highly prospective in the development of osteogenic scaffolds. Calcium poly(ethylene phosphate)s (PEP-Ca) appear to be potentially suitable candidates primarily because of PEP's biodegradability. In a series of experiments with human adipose-tissue-derived multipotent mesenchymal stem cells (ADSCs), we demonstrated that PEP-Ca are non-toxic and give rise to osteogenesis gene marker, bone morphogenetic protein 2 (BMP-2) and mineralization of the intercellular matrix. Owing to the synthetic availability of poly(ethylene phosphoric acid) block copolymers, these results hold out the possibility for the development of promising new polymer composites for orthopaedic and maxillofacial surgery.


Assuntos
Fosfatos de Cálcio/farmacologia , Cálcio/farmacologia , Diferenciação Celular/efeitos dos fármacos , Células-Tronco Mesenquimais/citologia , Osteogênese/efeitos dos fármacos , Polietileno/farmacologia , Calcificação Fisiológica/efeitos dos fármacos , Cálcio/química , Fosfatos de Cálcio/química , Adesão Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Matriz Extracelular/efeitos dos fármacos , Matriz Extracelular/metabolismo , Humanos , Células-Tronco Multipotentes/citologia , Células-Tronco Multipotentes/efeitos dos fármacos , Ácidos Fosfóricos/síntese química , Ácidos Fosfóricos/química , Polietileno/química
16.
Top Curr Chem (Cham) ; 378(1): 9, 2019 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-31879793

RESUMO

Asymmetric metal/organo relay catalysis, utilizing a metal complex and a chiral organocatalyst in a one-pot cascade reaction, is aimed to sequentially impart activation on multiple steps by distinct catalysts. Such a catalysis merges the advantages of both metal catalysis and organocatalysis, providing step-economy, and, more importantly, the potential to achieve inaccessible reactivity by a single catalyst. Chiral phosphoric acids are among the most robust organocatalysts, rendering a broad range of enantioselective bond-forming reactions. The combination of metal complexes and chiral phosphoric acids in a single vessel has been well documented. In particular, the asymmetric relay catalysis of metal complex with chiral phosphoric acid has grown rapidly since 2008. Several excellent reviews have been published to cover almost all examples in this area from 2008 to early 2014; therefore, in this chapter, we will mainly highlight progress from 2014 to mid-2019.


Assuntos
Complexos de Coordenação/química , Ácidos Fosfóricos/química , Catálise , Estrutura Molecular , Estereoisomerismo
17.
Braz Oral Res ; 33: e098, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31664361

RESUMO

The aim was to evaluate the effect of 2% grape seed extract (GSE) containing phosphoric acid (PhA) on the bond strength to enamel and dentin. The control group was 37% PhA. The following three PhA formulations with 2% GSE and 20% ethanol were obtained: GSE5 = 5% PhA; GSE10 = 10% PhA; and GSE20 = 20% PhA. The enamel and dentin surfaces of molars were etched with the acid solutions, followed by Scotchbond Multi-Purpose adhesive and composite resin application. The tensile bond strength (TBS) test evaluated the bond to enamel after 24 h, and the microtensile bond strength (µTBS) test evaluated the bond to dentin after 24 h and 12-month water storage. Etched enamel and dentin were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. The TBS data were submitted to one-way ANOVA, while µTBS data were submitted to two-way ANOVA and Tukey's test (α = 0.05). The TBS (MPa) to enamel did not significantly differ among the control (48.1 ± 15.7), GSE5 (46.1 ± 9.6), GSE10 (49.8 ± 13.6) and GSE20 (44.1 ± 11.9) groups (p = 0.537). The µTBS (MPa) to dentin of the control (28.4 ± 14.4) and GSE20 (24.1 ± 8.1) groups were significantly higher than those of the GSE5 (16.8 ± 7.4) and GSE10 (17.5 ± 6.6) groups at 24 h (p < 0.006). After 12-month storage, only GSE5 (21.0 ± 7.8) and GSE10 (17.6 ± 8.0) did not show significantly decreased µTBS (p > 0.145). SEM micrographs showed a shallower enamel etching pattern for GSE5. AFM images showed the formation of collagenous globular structures for GSE5 and GSE10. The different acid solutions did not influence the TBS to enamel, and the µTBS to dentin was stable over time when dentin was etched with GSE5 and GSE10.


Assuntos
Condicionamento Ácido do Dente/métodos , Colagem Dentária/métodos , Esmalte Dentário/efeitos dos fármacos , Dentina/efeitos dos fármacos , Extrato de Sementes de Uva/química , Ácidos Fosfóricos/química , Adolescente , Adulto , Análise de Variância , Esmalte Dentário/química , Dentina/química , Humanos , Teste de Materiais , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Valores de Referência , Reprodutibilidade dos Testes , Estatísticas não Paramétricas , Propriedades de Superfície/efeitos dos fármacos , Resistência à Tração , Fatores de Tempo , Adulto Jovem
18.
Chem Commun (Camb) ; 55(86): 12916-12919, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31603445

RESUMO

An enantioselective aerobic decarboxylative Povarov reaction of N-aryl α-amino acids with methylenephthalimidines through cooperative photoredox and chiral Brønsted acid catalysis is reported. With a transition metal-free dual catalytic system including a chiral phosphoric acid and DPZ as a photosensitizer mediated by visible light, the transformations provided a series of valuable chiral isoindolin-1-ones containing a 3,3-spiro-tetrahydroquinoline-based stereocenter in high yields (up to 83%) with good to excellent enantioselectivities (up to 98% ee) and excellent diastereoselectivity (>20 : 1 dr).


Assuntos
Aminoácidos/química , Luz , Ácidos Fosfóricos/química , Ftalimidas/química , Catálise , Oxirredução , Compostos de Espiro/química , Estereoisomerismo
19.
Molecules ; 24(18)2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31492010

RESUMO

Phosphonic acids, aminophosphonic acids, and phosphonocarboxylic acids are characterized by an advanced hyphenated technique, combining potentiometric titration with NMR spectroscopy. Automated measurements involving 13C, 19F and 31P nuclei lead to "pseudo 2D NMR" spectra, where chemical shifts or coupling constants are correlated with analytical parameters. Dissociation constants, stability constants, dynamic and specific chemical shifts are determined. Macroscopic and microscopic dissociation equilibria are discussed.


Assuntos
Espectroscopia de Ressonância Magnética , Compostos Organofosforados/química , Espectroscopia de Ressonância Magnética/métodos , Ácidos Fosfóricos/química , Proteólise
20.
Molecules ; 24(18)2019 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-31546939

RESUMO

Scallop-shell powder (SSP) heated at high temperature exhibits high pH and broad antimicrobial activity. Bioshell calcium oxide (BiSCaO) is an SSP composed mainly of calcium oxide. It is poorly water-soluble under alkaline conditions and the generated precipitate can plug spray nozzles. The aim of this study was to establish that BiSCaO dispersion caused no significant CaO loss and plugging of spray nozzles, and to evaluate its deodorization and microbicidal abilities and its ability to reduce the concentrations of NO2- and NO3-. BiSCaO dispersions were prepared by mixing various concentrations of BiSCaO suspension, while phosphate compounds such as Na3PO4, Na2HPO4 or NaH2PO4 and the pH, average diameter, zeta potential, and form of the compounds with cryo-SEM were evaluated. We evaluated deodorization using tainted pork meat and microbicidal efficacy using contaminated suspension with normal bacterial flora. The concentration of NO2- and NO3- after mixing BiSCaO dispersion and pure water containing a high proportion of NO2- and NO3- were measured. BiSCaO dispersion formed with Na2HPO4, whose ratio to BiSCaO was 60%, showed a high pH (>12), a small particle diameter (>181 nm) and was stable for seven days. The BiSCaO dispersion showed higher deodorization and microbicidal activities than SSP-Ca(OH)2, which was mainly composed of Ca(OH)2. BiSCaO, but not SSP-Ca(OH)2, could reduce the concentration of NO2- and NO3- by more than 90% within 15 min. We developed a stable BiSCaO dispersion, and it had high deodorization and microbicidal efficacy. These activities of BiSCaO might result from the high pH caused by CaO hydration and a reduction activity causing active radical species.


Assuntos
Exoesqueleto/química , Antibacterianos/farmacologia , Compostos de Cálcio/farmacologia , Nanopartículas/química , Óxidos/farmacologia , Animais , Nanopartículas/ultraestrutura , Nitratos/análise , Nitritos/análise , Tamanho da Partícula , Pectinidae/química , Ácidos Fosfóricos/química , Suspensões , Suínos
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