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1.
Adv Healthc Mater ; 8(24): e1901301, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31763779

RESUMO

Due to their excellent size, designability, and outstanding targeted antibacterial effects, nanoparticles have become a potential option for controlling oral biofilm-related infections. However, the formation of an oral biofilm is a dynamic process, and factors affecting the performance of antibiofilm treatments are complex. As such, when examining the existing literature on the antibiofilm effects of nanoparticles, attention should be paid to the specific mechanisms of action at different stages of oral biofilm formation, as well as relevant influencing factors, in order to achieve an objective and comprehensive evaluation. This review is intended to detail the antibacterial mechanisms of nanoparticles during the four stages of the formation of oral biofilms: 1) acquired film formation; 2) bacterial adhesion; 3) early biofilm development; and 4) biofilm maturation. In addition, factors influencing the antibiofilm properties of nanoparticles are summarized from the aspects of nanoparticles themselves, biofilm models, and host factors. The limitations of current research and possible trends for future research are also discussed. In summary, nanoparticles are a promising antioral biofilm strategy. It is hoped that this review can serve as a reference and inspire ideas for further research on the application of nanoparticles for effectively targeting and treating oral biofilms.

2.
Huan Jing Ke Xue ; 40(3): 1287-1294, 2019 Mar 08.
Artigo em Chinês | MEDLINE | ID: mdl-31087976

RESUMO

It is of great significance to analyze the runoff pollution load characteristics of different roof materials to improve the estimation accuracy of urban non-point source pollution loads. Yangzhou City was selected as the study area. There, three types of roofs were chosen for rainfall-runoff monitoring, including a Chinese style tile roof, cement tile roof, and concrete flat roof. The pollutant concentrations, scour law, and first flush effect of the three types of roofs were compared. The results show that the event mean concentration (EMC) of total nitrogen (TN), total phosphorus (TP), permanganate index, and total suspended solids (TSS) in the runoff of Chinese style tile roofs are around 4-9 times that in the runoff of cement tile roofs. The rainfall intensity exhibits stronger effect on the change in pollutant concentrations of runoff from the Chinese style tile roof than that from the cement tile roof. The Pearson correlation coefficients (r) of rainfall intensity against TP and TSS in time series were 0.853 and 0.822, respectively. The first flush intensities of the three types of roof materials were in the order cement tile roof > concrete flat roof > Chinese style tile roof. It was found that 60.0% of the roof runoff pollution load could be reduced by intercepting 31.5%, 58.0%, and 60.4% of the initial runoff for the Chinese style tile roof, the cement tile roof, and the concrete flat roof, respectively. The actual emissions of TN, TP, and TSS, and the permanganate index in rainstorm events would be significantly underestimated when roof materials are not distinguished. This would have negative effects on the pollution control of urban non-point sources. It is demonstrated that the fine distinction of roof materials is able to improve the estimation accuracy of urban non-point source loads.

3.
J Am Chem Soc ; 138(29): 9061-4, 2016 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-27416357

RESUMO

The search for new and efficient nonlinear optical (NLO) materials has been an active research because of their technological importance in laser applications. Although a large number of frequency-doubling oxides, phosphates, borates, and fluoride-containing borates were found, no transition-metal silicate with useful NLO properties has been reported. We have now synthesized and grown crystals of two new titanosilicates, Li2K4[(TiO)Si4O12] and Li2Rb4[(TiO)Si4O12], by using a flux and supercritical hydrothermal method. Their unique 3D framework structures contain highly compressed TiO5 square pyramids which are arranged one over the other to form infinite ···Ti-O···Ti-O straight chains with alternating short and long Ti-O distances. These two materials meet the requirements for efficient second harmonic generation including lack of center of inversion symmetry, large susceptibility, phase matching, transmitting at wavelengths of interest, resistant to laser damage, and thermally stable. These attributes make them very attractive for frequency-doubling materials.

4.
Chin Med J (Engl) ; 123(11): 1441-6, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20819604

RESUMO

BACKGROUND: Ascorbic acid has important antioxidant properties, and may play a role in the protective effects of ischemic preconditioning on later ischemia-reperfusion. Herein, we examined the role of endogenous extracellular ascorbic acid in ischemic preconditioning in the kidney. METHODS: We developed a solitary rabbit kidney model where animals received ischemia-reperfusion only (ischemia-reperfusion group, n = 15) or ischemic preconditioning followed by ischemia-reperfusion (ischemic preconditioning group, n = 15). Ischemia-reperfusion was induced by occluding and loosening of the renal pedicle. The process of ischemic preconditioning included 15-minute brief ischemia and 10-minute reperfusion. In vivo microdialysis coupled with online electrochemical detection was used to determine levels of endogenous extracellular ascorbic acid in both groups. The extent of tissue damage was determined in kidney sections stained with hematoxylin and eosin. Serum creatinine and urea nitrogen were also detected to assess renal function. RESULTS: During ischemia-reperfusion, the extracellular ascorbic acid concentration during ischemia increased rapidly to the peak level ((130.01 +/- 9.98)%), and then decreased slowly to near basal levels. Similar changes were observed during reperfusion (peak level, (126.78 +/- 18.24)%). In the ischemic preconditioning group there was a similar pattern of extracellular ascorbic acid concentration during ischemic preconditioning. However, the ascorbic acid level was significantly lower during the ischemia and early reperfusion stage compared to the ischemia-reperfusion group. Additionally, the extent of glomerular ischemic collapse, tubular dilation, tubular denudation, and loss of brush border were markedly attenuated in the ischemic preconditioning group. Levels of serum creatinine and urea nitrogen were also decreased significantly in the ischemic preconditioning group. CONCLUSIONS: Ischemic preconditioning may protect renal tissue against ischemia-reperfusion injury via use of extracellular ascorbic acid. In vivo microdialysis coupled with online electrochemical detection is effective for continuous monitoring extracellular ascorbic acid in the renal cortex.


Assuntos
Ácido Ascórbico/metabolismo , Precondicionamento Isquêmico/métodos , Rim/metabolismo , Traumatismo por Reperfusão/prevenção & controle , Animais , Modelos Animais de Doenças , Rim/patologia , Coelhos
5.
Chin Med J (Engl) ; 121(12): 1120-5, 2008 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-18706231

RESUMO

BACKGROUND: Ascorbic acid (AA) represents one of the most important enzyme co-factors, antioxidants and neuromodulators and plays an important role in the cerebral system. Increasing evidence has suggested that AA could treat certain kinds of vertigo diseases such as Meniere's disease. To elucidate the neurochemical functions associated with AA in vertigo, the change of extracellular AA in the brain cortex following caloric vestibular stimulation (CVS) was evaluated. METHODS: An on-line electrochemical detection was coupled with in vivo microdialysis to continuously monitor the change of extracellular AA in the primary somatosensory (SI) area of guinea pigs following a caloric vestibular stimulation. Sixteen guinea pigs were divided into three groups, i.e., experimental group with irrigation of the ear canal with ice water (0 degrees C) (n = 8), and two control groups, one with irrigation of the ear canal with warm water (38 degrees C) (n = 4) and the other with irrigation of the auricle with ice water (n = 4). RESULTS: In the experimental group, the ice water irrigation of the left external ear canal induced a horizontal nystagmus towards the right side lasting about 45 seconds. No nystagmus was induced by warm water irrigation of the external ear canal or by ice water irrigation of the auricle. The extracellular AA concentration significantly increased following the ice water vestibular stimulation, reaching a maximum of (130 +/- 20)% (n = 8) of the basal dialysate level (2.61 +/- 0.92) micromol/L (n = 8), lasting at least for an hour. AA level did not change distinctly after the irrigation of the left external ear canal with warm water or the irrigation of the auricle with ice water. CONCLUSIONS: The concentration of extracellular AA in the brain cortex of the SI area increased following the ice water vestibular stimulation. This demonstration may be useful for the investigation of the neurochemical processes associated with AA in the process of vertigo.


Assuntos
Ácido Ascórbico/análise , Córtex Cerebral/metabolismo , Gelo , Vestíbulo do Labirinto/fisiopatologia , Animais , Eletroquímica/métodos , Espaço Extracelular/metabolismo , Cobaias , Masculino , Microdiálise/métodos , Estimulação Física/métodos
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