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1.
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
2.
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
3.
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 Ambiente
4.
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
5.
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
6.
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
7.
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
8.
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
9.
Mater Sci Eng C Mater Biol Appl ; 104: 109914, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31500030

RESUMO

To improve the clinical efficiency of cytotoxic anticancer drugs e.g. doxorubicin (DOX), reduce the severe off-target side effects, and allow the more biocompatible and biodegradable drug penetration into tumor cells, our research efforts developed a new DOX-conjugated protein polymer nanoconjugates (PPNCs) prodrugs delivery system. Briefly, DOX was conjugated to bovine serum albumin (BSA) and the complex was treated with lactobionic acid (LA) as well as folic acid (FA) to enhance drug endocytosis and targeting selectivity. Such functionalized BSA could be conjugated with a designed phenylboronic acid functionalized poly(N-isopropylacrylamide) (PNIPAAm) via forming a pH-sensitive borate ester bond to give the functionalized PPNCs prodrugs. The potential of the PPNCs prodrugs on tumor cells therapy was systematically evaluated in dose/time-dependent effects. In vitro results showed a rapid accumulation of the prodrugs into the MDA-MB-231 tumor cell during the first 30 min and reached maximum at 24 h. Moreover, the cell-killing effect was observed quickly after 4 h incubation with an IC50 of 0.5 mg/mL (≈4 µM/L). In general, given the efficient pH-dependent DOX release of these constructed nanoconjugates, it is anticipated to contribute a potential delivery strategy for cancer therapy.


Assuntos
Boratos/química , Sistemas de Liberação de Medicamentos , Ésteres/química , Nanoconjugados/química , Polímeros/química , Soroalbumina Bovina/química , Animais , Antineoplásicos/farmacologia , Ácidos Borônicos/química , Bovinos , Linhagem Celular Tumoral , Dissacarídeos/química , Doxorrubicina/farmacologia , Ácido Fólico/química , Humanos , Concentração de Íons de Hidrogênio , Pró-Fármacos/farmacologia , Fatores de Tempo
10.
Chemistry ; 25(58): 13275-13279, 2019 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-31398268

RESUMO

Manipulation of the emerging anion-π interactions in a highly cooperative manner through sophisticated host design represents a very challenging task. In this work, unprecedented tetrahedral anion-π receptors have been successfully constructed for complementary accommodation of tetrahedral and relevant anions. The synthesis was achieved by a macrocycle-directed approach by using large macrocycle precursors bearing four reactive sites, which enabled a kinetic-favored pathway and afforded the otherwise inaccessible tetrahedral cages in considerable yields. Crystal structure suggested that the tetrahedral cages have an enclosed three-dimensional cavity surrounded by four electron-deficient triazine faces in a tetrahedral array. The complementary accommodation of a series of tetrahedral and relevant anions including BF4 - , ClO4 - , H2 PO4 - , HSO4 - , SO4 2- and PF6 - was revealed by ESI-MS and DFT calculations. Crystal structures of ClO4 - and PF6 - complexes showed that the anion was nicely encapsulated within the tetrahedral cavity with up to quadruple cooperative anion-π interactions by an excellent shape and size match. The strong anion-π binding was further confirmed by negative ion photoelectron spectroscopy measurements.


Assuntos
Compostos Macrocíclicos/química , Triazinas/química , Ânions/química , Boratos/química , Reagentes para Ligações Cruzadas/química , Cristalização , Teoria da Densidade Funcional , Estrutura Molecular , Percloratos/química , Espectrometria de Massas por Ionização por Electrospray , Sulfatos/química
11.
Anal Chim Acta ; 1079: 180-191, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31387709

RESUMO

In this research, a novel Resonance Rayleigh Scattering (RRS) aptasensor was developed for thrombin monitoring using in-situ synthesized and embedded Au nanoparticles (AuNPs) into poly vinyl alcohol -borax hydrogel (PBH). Thiolated-thrombin binding aptamer (thiolated-TBA) was attached to the surface of AuNPs embedded into PBH to design the PBH-aptasensor for thrombin detection (thiolated-TBA@AuNPs-PBH). To verify the characteristic and morphology of PBH nanocomposite, energy dispersive X-ray analysis, TEM, average particle size analizer and UV-Vis spectra were performed. The difference in RRS intensities in the absence and presence of thrombin was calculated and selected as the monitoring signal. Effect of different parameters on the RRS signal was investigated at excitation wavelength of 500 nm. Under the approved conditions, the linear detection range was validated over the concentration of 0.70 pM- 0.02 µM. The limit of detection based on 3Sb was 0.10 pM. The relative standard deviation for 5.6 pM and 3.6 nM were 4.0 and 2.7% (n = 10), respectively. The proposed aptasensor was successfully applied as an experimental model for thrombin detection in serum samples of healthy volunteers with acceptable results.


Assuntos
Aptâmeros de Nucleotídeos/química , Hidrogéis/química , Trombina/análise , Técnicas Biossensoriais/métodos , Boratos/química , Ouro/química , Humanos , Limite de Detecção , Nanopartículas Metálicas/química , Álcool de Polivinil/química , Espalhamento de Radiação , Análise Espectral/métodos , Trombina/química
12.
Carbohydr Res ; 484: 107773, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31404813

RESUMO

An HPLC method suitable for rapid monitoring of lactulose production by isomerization from lactose was developed. The separation of lactose and lactulose under hydrophilic interaction liquid chromatography (HILIC) mode was achieved with resolution 1.5 within 5 min. Since isocratic elution was used, there is no extra time necessary for the column equilibration. Application of the method was illustrated on monitoring lactulose isomerization with catalysis of sodium hydroxide in the presence of sodium tetraborate at 70 °C (pH = 11). The conversion yield obtained for lactulose was 86%, and corresponding purity 76%. For the first time, a polyhydroxy stationary phase for separation of lactose and lactulose is reported.


Assuntos
Fracionamento Químico/métodos , Lactose/química , Lactulose/análise , Boratos/química , Catálise , Cromatografia Líquida de Alta Pressão , Temperatura Alta , Interações Hidrofóbicas e Hidrofílicas , Isomerismo , Lactose/análise , Lactulose/química , Hidróxido de Sódio/química
13.
Molecules ; 24(15)2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-31366034

RESUMO

Borates have been regarded as a rich source of functional materials due to their diverse structures and wide applications. Therein, zincobrates have aroused intensive interest owing to the effective structural and functional regulation effects of the strong-bonded zinc cations. In recent decades, numerous zincoborates with special crystal structures were obtained, such as Cs3Zn6B9O21 and AZn2BO3X2 (A = Na, K, Rb, NH4; X = Cl, Br) series with KBe2BO3F2-type layered structures were designed via substituting Be with Zn atoms, providing a feasible strategy to design promising non-linear optical materials; KZnB3O6 and Ba4Na2Zn4(B3O6)2(B12O24) with novel edge-sharing [BO4]5- tetrahedra were obtained under atmospheric pressure conditions, indicating that extreme conditions such as high pressure are not essential to obtain edge-sharing [BO4]5--containing borates; Ba4K2Zn5(B3O6)3(B9O19) and Ba2KZn3(B3O6)(B6O13) comprise two kinds of isolated polyborate anionic groups in one borate structure, which is rarely found in borates. Besides, many zincoborates emerged with particular physicochemical properties; for instance, Bi2ZnOB2O6 and BaZnBO3F are promising non-linear optical (NLO) materials; Zn4B6O13 and KZnB3O6 possess anomalous thermal expansion properties, etc. In this review, the synthesis, crystal structure features and properties of representative zincoborates are summarized, which could provide significant guidance for the exploration and design of new zincoborates with special structures and excellent performance.


Assuntos
Boratos/química , Dispositivos Ópticos , Zinco/química , Boratos/síntese química , Cátions Bivalentes , Cristalização , Cristalografia por Raios X , Humanos , Modelos Moleculares
14.
J Chromatogr A ; 1602: 397-408, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31285058

RESUMO

In reversed-phase liquid chromatography, the performance for basic compounds is affected by the interaction of the protonated (cationic) species with the anionic free silanols on the alkyl-bonded stationary phases. Using aqueous-organic mobile phases in the absence of additives, the retention may be too high, and the peaks be broad and asymmetric. The performance is improved by addition to the mobile phase of ionic liquids, from which 1-hexyl-3-methylimidazolium chloride ([C6MIm][Cl]) has especially good characteristics. A recent report has also revealed that the use of the phosphate system as buffer, at varying concentration and pH, may have a significant role in the chromatographic performance of basic compounds, with effects on both retention and peak shape. In this work, this study has been extended to other three buffer systems (acetate, citrate, and formate), at increasing concentrations and pH 3 and 7, in the presence and absence of [C6MIm][Cl]. The results have been compared with those obtained with the phosphate system. The retention increases by addition of larger concentration of all buffers, in both absence and presence of [C6MIm][Cl]. Without additive, peak performance is also enhanced significantly. This effect is minimal in the presence of [C6MIm][Cl], which yields highly symmetrical peaks at all buffer concentrations, due to an effective blocking of the silanol activity.


Assuntos
Boratos/química , Cromatografia de Fase Reversa/métodos , Imidazóis/química , Acetonitrilos/química , Antagonistas Adrenérgicos beta/análise , Tampões (Química) , Cromatografia Líquida de Alta Pressão/métodos , Concentração de Íons de Hidrogênio , Líquidos Iônicos/química , Solventes , Água/química
15.
Nucleic Acids Res ; 47(17): e102, 2019 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-31318972

RESUMO

Terminal deoxynucleotidyl transferase (TdT), which mediates template-independent polymerization with low specificity for nucleotides, has been used for nucleotide extension of DNA oligomers. One concern is that it is difficult to control the number of incorporated nucleotides, which is a limitation on the use of TdT for single-nucleotide incorporation of DNA oligomers. Herein, we uncovered an interesting inhibitory effect on TdT when ribonucleotide substrates (rNTPs) were employed in a borate buffer. On the basis of unique inhibitory effects of the ribonucleotide-borate complex, we developed a novel enzymatic method for single-nucleotide incorporation of a DNA oligomer with a modified rNTP by TdT. Single-nucleotide incorporation of a DNA oligomer with various modified rNTPs containing an oxanine, biotin, aminoallyl or N6-propargyl group was achieved with a high yield. The 'TdT in rNTP-borate' method is quite simple and efficient for preparing a single-nucleotide modified DNA oligomer, which is useful for the design of functional DNA-based systems.


Assuntos
Boratos/química , DNA Nucleotidilexotransferase/metabolismo , Oligodesoxirribonucleotídeos/química , Ribonucleotídeos/química , Compostos Alílicos/química , Biotina/química , Tampões (Química) , DNA Nucleotidilexotransferase/antagonistas & inibidores , Oligodesoxirribonucleotídeos/biossíntese , Polimerização , Nucleosídeos de Purina/química
16.
Molecules ; 24(13)2019 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-31262097

RESUMO

Zinc borates are important chemical products having industrial applications as functional additives in polymers, bio-composites, paints and ceramics. Of the thirteen well documented hydrated binary zinc borates, Zn[B3O4(OH)3] (2ZnO∙3B2O3∙3H2O) is manufactured in the largest quantity and is known as an article of commerce as 2ZnO∙3B2O3∙3.5H2O. Other hydrated zinc borates in commercial use include 4ZnO∙B2O3∙H2O, 3ZnO∙3B2O3∙5H2O and 2ZnO∙3B2O3∙7H2O. The history, chemistry, and applications of these and other hydrated zinc borate phases are briefly reviewed, and outstanding problems in the field are highlighted.


Assuntos
Boratos/química , Cerâmica/química , Cerâmica/síntese química , Zinco/química , Boratos/síntese química
17.
J Contemp Dent Pract ; 20(5): 587-592, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31316023

RESUMO

AIM: The aim of this study is to evaluate and compare the amount of radicular peroxide penetration when various concentrations of carbamide peroxide (CP) bleaching gels (10, 15, and 35%) and a mixture of 30% hydrogen peroxide (HP) with sodium perborate are used for intracoronal bleaching. MATERIALS AND METHODS: Fifty extracted single-rooted premolars from young adults were used. The specimens were then divided into five groups such that teeth with varying sizes were equally distributed in all groups. Group I-distilled water (control group), group II-10% CP, group III-15% CP, group IV-35% CP, and group V-30% HP with sodium perborate. Intermediate restorative material (IRM) was used to seal access cavities and left for a week at 37 °C in an incubator. Following the bleaching process, suspended teeth from plastic tubes containing distilled water were removed and the water was used to determine the amount of peroxide levels. A UV-visible spectrophotometer at a wavelength of 480 nm was used to determine the quantity of peroxide based on the optical density. RESULTS: Results showed the highest peroxide leakage in group V, followed by group IV, and then group III, whereas the least peroxide penetration was found in group II, and the control group or group I showed no penetration. The Kruskal-Wallis test showed a significant difference between the various groups tested. The Mann-Whitney test was done to find in which pair of groups there exists a significant difference. It was found that all the groups when compared among themselves showed a significant difference. CONCLUSION: The present study concluded that lower concentrations of CP 10 and 15% produced lower peroxide leakage. Hence, it could be tried as an alternate to traditional agents in cases with compromised tooth which shows cervical tooth defects where the risk of external root resorption is higher. CLINICAL SIGNIFICANCE: The management of discolored teeth involves different techniques; among various techniques, bleaching is considered to be a safe, effective, and relatively noninvasive technique to lighten discolored teeth and it also conserves dental hard tissue.


Assuntos
Clareamento Dental , Descoloração de Dente , Boratos , Peróxido de Carbamida , Géis , Humanos , Peróxido de Hidrogênio , Peróxidos , Ureia , Adulto Jovem
18.
Oncol Rep ; 42(1): 115-130, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31180554

RESUMO

Borax is a boron compound that is becoming widely recognized for its biological effects, including lipid peroxidation, cytotoxicity, genotoxicity, antioxidant activity and potential therapeutic benefits. However, it remains unknown whether exposure of human liver cancer (HepG2) cells to borax affects the gene expression of these cells. HepG2 cells were treated with 4 mM borax for either 2 or 24 h. Gene expression analysis was performed using Affymetrix GeneChip Human Gene 2.0 ST Arrays, which was followed by gene ontology analysis and pathway analysis. The clustering result was validated using reverse transcription­quantitative polymerase chain reaction. A cell proliferation assay was performed using Celigo Image Cytometer Instrumentation. Following this, 2­ or 24­h exposure to borax significantly altered the expression level of a number of genes in HepG2 cells, specifically 530 genes (384 upregulated and 146 downregulated) or 1,763 genes (1,044 upregulated and 719 downregulated) compared with the control group, respectively (≥2­fold; P<0.05). Twenty downregulated genes were abundantly expressed in HepG2 cells under normal conditions. Furthermore, the growth of HepG2 cells was inhibited through the downregulation of PRUNE1, NBPF1, PPcaspase­1, UPF2 and MBTPS1 (≥1.5­fold, P<0.05). The dysregulated genes potentially serve important roles in various biological processes, including the inflammation response, stress response, cellular growth, proliferation, apoptosis and tumorigenesis/oncolysis.


Assuntos
Boratos/farmacologia , Perfilação da Expressão Gênica/métodos , Neoplasias Hepáticas/genética , Proliferação de Células/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Redes Reguladoras de Genes/efeitos dos fármacos , Células Hep G2 , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Análise de Sequência com Séries de Oligonucleotídeos
19.
Environ Toxicol Pharmacol ; 70: 103208, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31207443

RESUMO

Boron (B) has been widely used and contaminated the aquatic ecosystem. However, knowledge of the effects of sodium pentaborate pentahydrate (SPP) on algae remains limited. This study aimed to assess SPP toxicity using multiple endpoints, specially detecting the intracellular metal ion concentrations, malondialdehyde (MDA) content and extracellular polymeric substance (EPS) classes for the very first time during SPP exposure to Chlorella vulgaris (C. vulgaris). Our findings indicated that the inhibitory effects of SPP on C. vulgaris may be related to nutrient absorption and utilization. The changes in intracellular starch grains, MDA and the protein-like substances in EPS probably acted as a defense mechanism, helping to alleviate the toxic effects. This work may contribute to the understanding of the mechanism of SPP toxicity in algae. Further studies may focus on the effects of B on speciation of metallic ions and the interaction of B with metallic ions on aquatic organisms.


Assuntos
Boratos/toxicidade , Chlorella vulgaris/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Chlorella vulgaris/crescimento & desenvolvimento , Chlorella vulgaris/metabolismo , Chlorella vulgaris/ultraestrutura , Matriz Extracelular de Substâncias Poliméricas/metabolismo , Malondialdeído/metabolismo , Microscopia Eletrônica de Transmissão
20.
J Endod ; 45(8): 1053-1059, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31155299

RESUMO

It has been reported that bond strength can be reversed to prebleached levels with the application of 10% alpha-tocopherol in a 2-hour time frame or by delaying bonding for 2 weeks. This study evaluated the effectiveness of a 5-minute application of 20% alpha-tocopherol to reverse the deleterious effects of nonvital bleaching on consequent bond strength. Thirty third molars were assigned to the following 3 groups: unbleached, bleached, and bleached followed by treatment with alpha-tocopherol. The bleached groups were exposed to sodium perborate (2 g/mL) for 7 days. The postbleach treatment group was subsequently treated with 20% alpha-tocopherol for 5 minutes, and then all groups were restored with composite resin. After 24 hours of storage at 37°C and 100% humidity, restored tooth specimens were sectioned into 1-mm2 dentin-composite beams. Six beams from each tooth were subjected to microtensile bond strength testing. Representative beams were further evaluated with Raman microspectroscopy and scanning electron microscopy. The mean bond strength values (MPa) for each group were as follows: unbleached control group = 26.2, bleached control group = 20.3, and post-bleach treatment group = 18.5. A 1-factor analysis of variance and Tukey post hoc test (α = 0.05) indicated that bleaching had a detrimental effect on bond strength and that short-term alpha-tocopherol treatments did not improve postbleach bond strength. Raman microspectroscopy and scanning electron microscopy revealed no noted improvement for the post-bleach treatment group.The application of 20% alpha-tocopherol in a clinically relevant time frame was not effective in counteracting the deleterious effect of bleaching on bond strength. Bonding procedures should be delayed after tooth bleaching.


Assuntos
Antioxidantes , Colagem Dentária , Dentina , Clareamento Dental , alfa-Tocoferol , Antioxidantes/farmacologia , Boratos , Resinas Compostas , Dentina/efeitos dos fármacos , Cimentos de Resina , Resistência à Tração , alfa-Tocoferol/farmacologia
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