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Objective To screen and establish a method for determining the biological activity of anfibatide.Meth-ods Three methods of light transmittance aggregometry(LTA),whole blood electrical impedance aggregometry,and continuous platelet count method were compared and studied.And the constant platelet counting method was chosen and verified to detect the biological activity of anfibatide.Results The RSD values of anfibatide biological activity detected by LTA,whole blood electri-cal impedance aggregometry,and continuous platelet count method were 10.3%,14.0%,and 3.6%,respectively.RSD of repeat-ability of 6 parallel test articles was 11.0%.The RSD of intermediate precision of 12 test articles for different personnel was 9.8%,and the inhibition rate of anfibatide was linear in the range of 0.3-0.5 U.The correlation coefficient was more than 0.990.The ac-tivity of three batches of anfibatide was determined,and the inhibition rate was 49.9%～53.6%.Conclusion The continuous platelet count method for determining anfibatide activity was established and verified,which can be used for quality control for an-fibatide activity since the precision and detection limit of the method met the requirement for activity assay of biological products.
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This study aimed to create and assess a novel self-microemulsifying drug delivery system (SMEDDS) for treating diabetes mellitus that contains glimepiride and Boswellia serrata extract. In the creation of SMEDDS formulations, Transcutol-P was employed as the base oil, while the surfactants Tween 80 and propylene glycol/polyethylene glycol 400 served as the co-surfactants. To improve the formulation, pseudoternary phase diagrams were created. While the SMEDDS of B. serrata extract showed a mean droplet size of 27.63 nm, 98.3% transmittance, a zeta potential of -0.11 mV, and a polydispersity index of 0.287, the glimepiride-optimized SMEDDS showed a mean droplet size of 14.8 nm, 98.5% transmittance, a zeta potential of -0.10 mV. In-vivo evaluation on diabetes-induced rats demonstrated significant reductions in SGOT and SGPT levels with the glimepiride and B. serrata extract SMEDDS compared to diabetic control rats and the marketed glimepiride formulation. The formulation showed promising results in controlling serum total protein, triglyceride, and cholesterol levels. The glimepiride and B. serrata extract SMEDDS also exhibited antioxidant activity, reducing malondialdehyde (MDA) absorbance. Histopathological assessment of kidney and pancreas tissues revealed the protective effects of the concomitant administration of glimepiride and B. serrata extract SMEDDS formulation against diabetes-induced damage. Overall, the developed SMEDDS formulation kit showed superior in-vitro and in-vivo performance, suggesting its potential as an effective therapeutic option for managing diabetes mellitus.
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Objective:To investigate the influence of different types of wound dressings on red light transmittance.Methods:A treatment environment for wounds exposed to red light was simulated.Red light transmittance of four types of 19 dressings commonly used in clinic were detected respectively and compared.The transmittance was calculated as the ratio of the intensity of the red light through the dressing to the intensity of the injected red light.Results:The red light transmittance for each dressing was the following: (1)Cotton gauze and pad: 29.4% for one piece of coarse gauze, 10.5% for one cotton pad; (2)Oil dressings: 73.0%~79.1% for light-color oil dressings, 41.7% for dark-color oil dressings-Atrauman ?; (3)Hydrocolloid dressings: 87.8%~90.2%; (4)Foams: 74.7% for light-color ultra-thin foam-Mepilex ? sheet, 0.8% for black-color thicker foam dressings-Mepilex ? Ag dressing, and 20.5%-54.2% for the other foam dressings. Conclusions:The red light transmittance of hydrocolloid dressing, light-colored oil gauze dressing and light-colored ultra-thin foam dressing is higher, with less red light-blocking effect, and the dark-color or thicker dressings had more blocking effect, which showed different therapeutic effect on wound.Gauze and cotton pad have great blocking influence on red light transmittance, and are not suitable for temporary covering of wound during red light treatment.Hence, the effect of wound dressing on red light transmittance should be taken into account when the wound is treated with red light.
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Background:@#High on-treatment platelet reactivity (HTPR) has been suggested as a risk factor for patients with ischemic vascular disease. We explored a predictive model of platelet reactivity to clopidogrel and the relationship with clinical outcomes.@*Methods:@#A total of 441 patients were included. Platelet reactivity was measured by light transmittance aggregometry after receiving dual antiplatelet therapy. HTPR was defined by the consensus cutoff of maximal platelet aggregation >46% by light transmittance aggregometry. CYP2C19 loss-of-function polymorphisms were identified by DNA microarray analysis. The data were compared by binary logistic regression to find the risk factors. The primary endpoint was major adverse clinical events (MACEs), and patients were followed for a median time of 29 months. Survival curves were constructed with Kaplan-Meier estimates and compared by logrank tests between the patients with HTPR and non-HTPR.@*Results:@#The rate of HTPR was 17.2%. Logistic regression identified the following predictors of HTPR: age, therapy regimen, body mass index, diabetes history, CYP2C19*2, or CYP2C19*3 variant. The area under the curve of receiver operating characteristic for the HTPR predictive model was 0.793 (95% confidence interval: 0.738–0.848). Kaplan-Meier analysis showed that patients with HTPR had a higher incidence of MACE than those with non-HTPR (21.1% vs. 9.9%; χ2 = 7.572, P = 0.010).@*Conclusions:@#Our results suggest that advanced age, higher body mass index, treatment with regular dual antiplatelet therapy, diabetes, and CYP2C19*2 or CYP2C19*3 carriers are significantly associated with HTPR to clopidogrel. The predictive model of HTPR has useful discrimination and good calibration and may predict long-term MACE.
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A near infrared spectroscopy ( NIRS) method was used for rapid quality evaluation of ferulic acid content in chrysanthemum morifolium cv. ( Chuju) continuous cropping soil. Standard leverage, studentized residual and Mahalanobis distance were calculated to eliminate abnormal samples. After the initial near infrared spectrum was treated by two second derivative and Norris smoothing filter noise, 6000-4000 cm-1 wave number range and 7 factors were chosen for partial least squares ( PLS) calibration model. The results showed that good correlation was presented between the calibration set/validation set and the values determined by high performance liquid chromatography, and the calibration correlation coefficient ( Rc ) and validation correlation coefficient ( Rcv ) were 0. 9914 and 0. 9935, respectively. Root mean square error of calibration (RMSEC), root mean square error of validation (RMSEP) and root mean square error of cross-validation (RMSECV) were 0. 484, 0. 539 and 0. 615, respectively. This method was accurate, reliable, simple, rapid and nondestructive, and could be applied to the fast analysis for ferulic acid in continuous cropping soil.
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Objective To study the physicochemical properties of aqueous solution of surface active drug montelukast so-dium (MS) ,which could provide experimental basis for further development of micelle or mixed micelle preparations .Methods Critical micelle concentration (CMC) of MS at different temperatures were determined by conductivity measurements .The absorbance and transmittance of MS aqueous solution were measured by UV at different sodium chloride concentration levels . The micelle stability was evaluated via high speed centrifugal .Results The CMC of MS aqueous solution at 25℃ ,30℃ ,35℃were 0 .75 ,0 .82 ,0 .90 mmol/L .The absorbance and transmittance of MS aqueous solution were affected by the sodium chlo-ride concentration and the concentration of MS itself .It was observed that a clear solution was obtained when MS concentration>7 .5 mmol/L and no precipitation was noticed even after high speed centrifugal .Conclusion Montelukast sodium is a surface active drug .Its solubility is related to MS concentration .The solubility is also sensitive to the temperature and the electrolyte concentration .These unique physicochemical properties could be used to develop micelle or mixed micelle pharmaceutical prepa-rations .
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Objective To compare the consistency of thrombelastography (TEG) and light transmittance aggregometry (LTA) in monitoring the antiplatelet therapy of the patients with coronary heart disease (CHD) after percutaneous coronary intervention (PCI),and observe the changes of mean platelet volume (MPV) of the patients treated with aspirin and clopidogrel after PCI.Methods A total of 177 patients undergoing PCI and the treatment of aspirin and clopidogrel in Peking University First Hospital during March 2014 and May 2015 were enrolled in the study.Their adenosine diphosphate (ADP) or arachidonic acid (AA) induced platelet inhibition rates determined by TEG,MPV before and after antiplatelet therapy,and the maximum platelet aggregation rates measured by LTA from 99 patients were retrospectively analyzed.Results There was no any correlation between the maximum aggregation rates measured by LTA and the platelet inhibition rates determined by TEG regardless of using ADP or AA as agonist (all P ＞ 0.05).The detection rates of clopidogrel hyporesponsiveness determined by LTA and TEG were 30.3％ and 45.5％,respectively,while those of aspirin hyporesponsiveness were 19.2％ and 31.3％,respectively.The detection rate of hyporesponsiveness determined by LTA was significant lower than that by TEG (P ＜ 0.05).The MPVs after antiplatelet therapy were significant lower than that before treatment (all P ＜ 0.01) regardless of clopidogrel hyporesponsive or sensitive and aspirin hyporesponsive or sensitive.The MPVs in clopidogrel hyporesponsive group before and after treatment were significantly lower than that in clopidogrel sensitive group (all P ＜ 0.05).The PLT counts in clopidogrel or aspirin hyporesponsive groups after treatment were significantly higher than that before treatment (all P ＜ 0.05).Conclusion There is poor correlation between LTA and TEG.It should be noted that the incidence rate of antiplatelet drug hyporesponsiveness is high in clinical practice.The MPVs of the patients significantly decrease after antiplatelet therapy.The patients with a significant increase of PLT after antiplatelet therapy are more likely to become drug hyporesponsiveness,while the patients with lower MPV are more likely to have clopidogrel hyporesponsiveness.
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<p><b>OBJECTIVE</b>This study aims to compare the three commonly used translucency parameters in prosthodontics: transmittance (T), contrast ratio (CR), and translucency parameter (TP).</p><p><b>METHODS</b>Six platelet specimens were composed of Vita enamel and dental porcelain. The initial thickness was 1.2 mm. The specimens were gradually ground to 1.0, 0.8, 0.6, 0.4, and 0.2 mm. T, color parameters, and reflection were measured by a spectrocolorimeter for each corresponding thickness. T, CR and TP were calculated and compared.</p><p><b>RESULTS</b>TP increased, whereas CR decreased, with decreasing thickness. Moreover, T increased with decreasing thickness, and exponential relationships were found. Two-way ANOVA showed statistical significance between T and thickness, except between T and the 1.2 mm and 1.0 mm enamel porcelain groups. No difference was found among the coefficient variations (CV) of T, CR and TP. Curve fitting indicated the existence of exponential relationships between T and CR and between T and TP. The values for goodness of fit with statistical significance were 0.951 and 0.939, respectively (P<0.05).</p><p><b>CONCLUSIONS</b>Under the experimental conditions, T, TP and CR achieved the same CV. T and TP, as well as T and CR, were found with exponential relationships. The value of CR and TP could not represent the translucency precisely, especially when comparing the changing ratios.</p>
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Color , Esmalte Dental , Porcelana Dental , ProstodonciaRESUMEN
El artículo propone estudiar la propagación de los campos electromagnéticos a través de la mitocondria. Se presenta un modelo simplificado de la mitocondria como un sistema periódico de multicapas de índices de refracción alternantes. Mediante el método de transferencia matricial se calcula la dependencia, la reflectancia y transmitancia en función de la longitud de onda del campo electromagnético incidente. Se observa la existencia de una región de longitudes de onda (o frecuencia prohibidas) en la cual no existe propagación de los campos a través del sistema, esto corresponde a una reflectancia máxima R=1.
The article aims to study the propagation of electromagnetic fields through the mitochondria. We present a simplified model of the mitochondrion as a periodic multilayer of alternating refractive indices. Using the transfer matrix method calculates dependence reflectance and transmittance versus wavelength of incident electromagnetic field. Observe the existence of a wavelength region (or prohibited frequency) in which there is no spread of the fields through the system, this corresponds to a maximum reflectance R = 1.
O artigo tem como objetivo estudar a propagação de campos eletromagnéticos através das mitocôndrias. Nós apresentamos um modelo simplificado da mitocôndria como uma multicamada periódica de alternância de índices de refração. Utilizando o método de matriz de transferência calcula reflectância dependência e transmitância contra o comprimento de onda de campo eletromagnético incidente. Note-se a existência de uma região de comprimento de onda (ou frequência proibida) em que não há nenhuma propagação dos campos através do sistema, isto corresponde a um máximo de reflectância R = 1.
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Objective:To evaluate the optical property of the light color core substructure ND1 overlaid by 4 different all-ceramic crowns respectively and to study the color difference between the crowns and target tab.Methods:Light color(ND1)substructures were made and were respectively tried in 4 groups of all-ceramic crowns (Procera alumina,Procera zirconia,Lava zirconia and IPS E.max glass-ceramic lithium disilicate-reinforced monolithic,n =10).The CIE L*,a*,b* values of the cervical part,body and incisal site of the samples were recorded and analyzed by a spectrophotometer before and after veneer.The color difference between the all-ceramic crowns and target A2 dentin tab was evaluated.The spectral integral transmittance of the 4 copings was measured by a spectrophotometer.Results:The L* values of the abutments was increased by all-ceramic copings of the 4 groups,a*values were decreased but b* changed inconsistently.After veneer,the L* values of all the copings declined significantly,the values of a* and b* increased.When compared with A2 tab,the ΔE of the crowns was 1.27 ~4.17.The mean value range of the transmittance of the coping was:E.max-LT A2 >Pro-Alu >Lava-Zir >Pro-Zir.Conclusion:The lightness,hue and light transmittance of the 4 ceramic copings are different.After veneer with A2 dentine,the difference of the lightness is declined but the difference of the hue is signifi-cant.The color difference of the Lava-Zir and IPS E.max is clinically unacceptable.
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Objective To analyze the relationship between the light transmittance and the color value of 3 different brands of zirconia dental ceramic materials of various thicknesses and colors, so as to provide evidence for a new indicator to the Colorimetric system to better simulate the natural dentin color. Methods X-rite color i7 spectrophotometer was used to measure the transmittance and reflectance (L*, a*, b*) of three brands (Lava, Upcera, Doceram) of zirconia ceramic materials of different colors and different thicknesses (0.9, 0.6 and 0.3 mm). The results were analyzed by SPSS18.0 software to investigate the linearity of transmittance with thickness and color values of the materials. Results The transmittance was not significantly different among the three brands of zirconia ceramic materials (P>0.05); the transmittance ranges of different thicknesses of zirconia ceramic (0.9, 0.6 and 0.3 mm) were 13.63%-27.47%, 18.05%-33.96%, and 25.24%-39.73%, respectively, showing significant difference (P<0.05). There was a linear relation of the transmittance with the thickness and color values of the three brands of zirconia ceramic materials: Upcera:TT=0.366×L*-thickness×0.661-0.280×b*; Doceram: TT=0.524×L*-0.536×thickness-0.237×b*; Lava: TT=0.210×L*-0.610×thickness-0.164×b*. Conclusion The transmittance ranges of the three brands of zirconia ceramic material are similar. The transmittance decreases with increase of its thickness and increases with luminance increase. Bluer zirconia ceramic has higher transmittance. Therefore, introduction of transmittance value for ceramic restoration process is important to redefine the natural tooth color perception and representation.
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Objective:To establish a rapid analysis method for determining the content of ephedrine in Biyan sprays. Methods:The FT-NIR spectra of the samples were collected by near-infrared liquid transmission spectroscopy. Using the HPLC analysis values as the reference, a quantitative analysis model for ephedrine was established with partial least square ( PLS) , the first derivative and Nor-ris smooth was used in the spectra pretreatment, and 6 136. 38-5 364. 99 cm-1 and 7 038. 90-6 969. 48 cm-1 were selected as the fre-quency ranges. Results:R2 and RMSEC of the calibration set was 0. 992 6 and 1. 20, respectively. R2 and RMSEP of the vallidation set was 0. 993 5 and 1. 28, respectively. R2 and RMSEP of the cross validation set was 0. 986 9 and 1. 60, respectively. Conclusion:The method is rapid and non-desturctive, and can be applied in the rapid assessment and online examination of the quality of Biyan sprays.
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O objetivo desta pesquisa foi avaliar a transmitância de diferentes tipos e cores de cerâmicas e seus efeitos no grau de conversão (GC) de dois tipos de cimentos resinosos com modo de polimerização dual. Foram confeccionadas 60 pastilhas com a cerâmica IPS e.max (Ivoclar Vivadent, Schaan, Liechtenstein) e divididas em 3 grupos: LT, MO e Z, com 20 pastilhas cada um. Nos grupos LT e MO, as pastilhas foram confeccionadas com a cerâmica de dissilicato de lítio de baixa translucidez (LT - low transluscency) e de média opacidade (MO - medium opacity), respectivamente. No grupo Z, as pastilhas foram confeccionadas em zircônia. Cada grupo foi subdividido em 5 subgrupos (n=4), de acordo com a cor da cerâmica: A2; A3,5; B2; C2; D3. No grupo LT, as pastilhas foram prensadas nas cores anteriormente citadas e, nos grupos MO e Z, as pastilhas foram, inicialmente, confeccionadas para simular infraestruturas e, posteriormente, receberem aplicação de cerâmica de revestimento IPS e.max Ceram (Ivoclar Vivadent, Schaan, Liechtenstein) nas mesmas cores. O espectrofotômetro UV 1800 Shimadzu foi utilizado para medir a transmitância de cada espécime de cerâmica (2,0 mm de espessura). Para medir o GC, espécimes dos cimentos resinosos Variolink II (Ivoclar Vivadent, Schaan, Liechtenstein) e Rely X U200 (3M ESPE, St. Paul, MN, USA), com espessura de 100 μm, foram fotopolimerizados sob os discos de cerâmica por 40 s. Espécimes dos cimentos fotoativados sem a interposição da cerâmica foram usados como grupo controle. A polimerização dos cimentos foi avaliada através da espectrometria no infravermelho com transformada de Fourier (FTIR) empregando o método de reflexão atenuada total (ATR) imediatamente após a fotopolimerização. Os resultados foram submetidos aos testes ANOVA a 1 critério e Teste de Tukey (α=5%). Os valores de transmitância foram inferiores a 1%, sendo que as do grupo LT apresentaram, em geral, os maiores valores de transmitância, seguidos dos grupos MO e Z. O GC do cimento...
The aim of the present study was to evaluate the transmittance of different ceramic types and shades and their effects on the degree of conversion (DC) of two dual-cure resin cements. Sixty discs were fabricated with IPS e.max ceramic (Ivoclar Vivadent, Schaan, Liechtenstein) and divided into three groups (n= 20 in each group): LT, MO and Z. For LT and MO groups discs were fabricated with low translucency (LT) and medium opacity (MO) lithium disilicate ceramic, respectively. Discs from Z group were manufactured of zirconia. Each group was divided into five subgroups (n = 4), according to the ceramic shade: A2; A3,5; B2; C2; D3. In the LT group, specimens were heat-pressed in shades cited above and in the MO and Z groups, the discs were initially fabricated as core materials and then veneered with veneer ceramic (IPS e.max Ceram, Ivoclar Vivadent, Schaan, Liechtenstein) in the same shades. A spectrophotometer UV-1800 Shimadzu was used to determine the transmittance percentage of each ceramic specimen (2.0-mm-thick). For DC measurements, the resin cements (Variolink II - Ivoclar Vivadent, Schaan, Liechtenstein and Rely X U200 - 3M ESPE, St. Paul, MN, USA) specimens (thickness: 100 μm) were photocured under the ceramic discs (2.0-mm-thick) for 40 s. Specimens photocured without the ceramics discs were used as control group. ATR/FTIR spectrometry was used to evaluated the extent of polymerization for all cement specimens immediately after photocuring. The results were submitted to one-way ANOVA and Tukey test (α=5%). The transmittance percentage was less than 1% and the LT group had the highest transmittance values, followed by MO and Z groups. The %DC of Variolink II cement was not influenced by the ceramic disc interposition. For Rely X U200 cement, the interposition of some ceramics types/shades (LT A3,5, MO A2, MO A3,5 and Z A3,5) significantly decreased the %DC compared to control group. It was concluded that the transmittance values and %DC...
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Humanos , Auto-Curación de Resinas Dentales/métodos , Color , Cerámica/química , Cementos de Resina/química , Curación por Luz de Adhesivos Dentales/métodos , Análisis de Varianza , Ensayo de Materiales , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
O objetivo desta pesquisa foi avaliar a transmitância de diferentes tipos e cores de cerâmicas e seus efeitos no grau de conversão (GC) de dois tipos de cimentos resinosos com modo de polimerização dual. Foram confeccionadas 60 pastilhas com a cerâmica IPS e.max (Ivoclar Vivadent, Schaan, Liechtenstein) e divididas em 3 grupos: LT, MO e Z, com 20 pastilhas cada um. Nos grupos LT e MO, as pastilhas foram confeccionadas com a cerâmica de dissilicato de lítio de baixa translucidez (LT - low transluscency) e de média opacidade (MO - medium opacity), respectivamente. No grupo Z, as pastilhas foram confeccionadas em zircônia. Cada grupo foi subdividido em 5 subgrupos (n=4), de acordo com a cor da cerâmica: A2; A3,5; B2; C2; D3. No grupo LT, as pastilhas foram prensadas nas cores anteriormente citadas e, nos grupos MO e Z, as pastilhas foram, inicialmente, confeccionadas para simular infraestruturas e, posteriormente, receberem aplicação de cerâmica de revestimento IPS e.max Ceram (Ivoclar Vivadent, Schaan, Liechtenstein) nas mesmas cores. O espectrofotômetro UV 1800 Shimadzu foi utilizado para medir a transmitância de cada espécime de cerâmica (2,0 mm de espessura). Para medir o GC, espécimes dos cimentos resinosos Variolink II (Ivoclar Vivadent, Schaan, Liechtenstein) e Rely X U200 (3M ESPE, St. Paul, MN, USA), com espessura de 100 μm, foram fotopolimerizados sob os discos de cerâmica por 40 s. Espécimes dos cimentos fotoativados sem a interposição da cerâmica foram usados como grupo controle. A polimerização dos cimentos foi avaliada através da espectrometria no infravermelho com transformada de Fourier (FTIR) empregando o método de reflexão atenuada total (ATR) imediatamente após a fotopolimerização. Os resultados foram submetidos aos testes ANOVA a 1 critério e Teste de Tukey (α=5%). Os valores de transmitância foram inferiores a 1%, sendo que as do grupo LT apresentaram, em geral, os maiores valores de transmitância, seguidos dos grupos MO e Z. O GC do cimento...
The aim of the present study was to evaluate the transmittance of different ceramic types and shades and their effects on the degree of conversion (DC) of two dual-cure resin cements. Sixty discs were fabricated with IPS e.max ceramic (Ivoclar Vivadent, Schaan, Liechtenstein) and divided into three groups (n= 20 in each group): LT, MO and Z. For LT and MO groups discs were fabricated with low translucency (LT) and medium opacity (MO) lithium disilicate ceramic, respectively. Discs from Z group were manufactured of zirconia. Each group was divided into five subgroups (n = 4), according to the ceramic shade: A2; A3,5; B2; C2; D3. In the LT group, specimens were heat-pressed in shades cited above and in the MO and Z groups, the discs were initially fabricated as core materials and then veneered with veneer ceramic (IPS e.max Ceram, Ivoclar Vivadent, Schaan, Liechtenstein) in the same shades. A spectrophotometer UV-1800 Shimadzu was used to determine the transmittance percentage of each ceramic specimen (2.0-mm-thick). For DC measurements, the resin cements (Variolink II - Ivoclar Vivadent, Schaan, Liechtenstein and Rely X U200 - 3M ESPE, St. Paul, MN, USA) specimens (thickness: 100 μm) were photocured under the ceramic discs (2.0-mm-thick) for 40 s. Specimens photocured without the ceramics discs were used as control group. ATR/FTIR spectrometry was used to evaluated the extent of polymerization for all cement specimens immediately after photocuring. The results were submitted to one-way ANOVA and Tukey test (α=5%). The transmittance percentage was less than 1% and the LT group had the highest transmittance values, followed by MO and Z groups. The %DC of Variolink II cement was not influenced by the ceramic disc interposition. For Rely X U200 cement, the interposition of some ceramics types/shades (LT A3,5, MO A2, MO A3,5 and Z A3,5) significantly decreased the %DC compared to control group. It was concluded that the transmittance values and %DC...
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Auto-Curación de Resinas Dentales/métodos , Color , Cerámica/química , Cementos de Resina/química , Curación por Luz de Adhesivos Dentales/métodos , Análisis de Varianza , Ensayo de Materiales , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
PURPOSE: Translucency and colour stability are two most important aspects for an aesthetic dental restoration. Glass ceramic restorations are popular amongst clinicians because of their superior aesthetic properties. In the last decade, zirconia has generated tremendous interest due to its favorable mechanical and biological properties. However, zirconia lacks the translucency that lithium disilicate materials possess and therefore has limitations in its use, especially in esthetically demanding situations. There has been a great thrust in research towards developing translucent zirconia materials for dental restorations. The objective of the study was to evaluate and compare the transmittance of a translucent variant of zirconia to lithium disilicate. MATERIALS AND METHODS: Two commercially available zirconia materials (conventional and high translucency) and 2 lithium disilicate materials (conventional and high translucency) with standardized dimensions were fabricated. Transmittance values were measured for all samples followed by a microstructural analysis using a finite element scanning electron microscope. One way analysis of variance combined with a Tukey-post hoc test was used to analyze the data obtained (P=.05). RESULTS: High translucency lithium disilicate showed highest transmittance of all materials studied, followed by conventional lithium disilicate, high translucency zirconia and conventional zirconia. The difference between all groups of materials was statistically significant. The transmittance of the different materials correlated to their microstructure analysis. CONCLUSION: Despite manufacturers' efforts to make zirconia significantly more translucent, the transmittance values of these materials still do not match conventional lithium disilicate. More research is required on zirconia towards making the material more translucent for its potential use as esthetic monolithic restoration.
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Cerámica , Estética , Vidrio , LitioRESUMEN
A pesquisa tem como objetivo a aplicação da transmitância espectral utilizando uma esfera de integração para estimar o Fator de Proteção Solar (FPS) de fotoprotetores comerciais para o uso infantil. Fotoprotetores com FPS 30 (A, B e C), disponíveis comercialmente, foram selecionados para avaliação conforme as seguintes metodologias: valor de pH, perfil reológico, e valor de FPS in vitro por espectroscopia. As amostras A, B e C apresentaram, respectivamente, os seguintes valores de pH: 7.8, 7.4 e 7.0. O perfil reológico identificou os sistemas como semissólidos pseudoplásticos não-Newtonianos, com área de histerese. O teste-T (p < 0.05) foi utilizado para confrontar o FPS alegado (FPS = 30) com o estimado por espectroscopia. Estudos in vitro foram considerados de grande importância para a área cosmética, podendo corroborar, previamente, a realização dos estudos de eficácia in vivo. De acordo com os resultados, as amostras A, B e C apresentaram valores de FPS sem diferença estatisticamente significativa, quando comparados àqueles citados nos rótulos. A transmitância espectral utilizando esfera de integração provou ser uma metodologia conveniente, rápida e reprodutível para a avaliação estimada do FPS.
This research focused on the measurement of spectral transmittance using an integrating sphere to estimate the Sun Protection Factor (SPF) of commercial sunscreens oriented for child use. Commercially available SPF 30 sunscreens (A, B and C) were selected and assessed by the following methodology: pH measurement; rheological profile analysis; and in vitro SPF estimation by spectroscopy. Samples A, B and C exhibited, respectively, pH values of 7.8, 7.4 and 7.0. The rheological profile identified the systems as pseudoplastic non-Newtonian semisolids with hysteresis loops. The t-test (p < 0.05) was used to confront the claimed SPF (SPF = 30) with that estimated by spectroscopy. In vitro tests are considered of utmost importance in the cosmetic , since their results may be used to validate submission to subsequent in vivo efficacy experiments. According to our results, sunscreens A, B and C generated SPF values without any significant difference from those claimed on the commercial sunscreen labels. The measurement of spectral transmittance with an integrating sphere proved to be a convenient, fast and reproducible method for SPF estimation.
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Reología , Análisis Espectral , Protectores SolaresRESUMEN
Objective: To explore the effect of ultrafiltration technology in the preparation of Xiangdan Injection on transmittance and impurity removal rates of protocatechuic aldehyde (PA) and sodium danshensu (SD), to evaluate its applicability, and to optimize the ultrafiltration technology. Methods: Taking the solution temperature, pH value, intercept relative molecular weight of ultrafiltration membrane, membrane import and export pressure difference of ultrafiltration membrane as influence factors, the process parameters of the ultrafiltration were optimized by detecting the contents and solid contents of PA and SD before and after the ultrafiltration. Results: The three factors of temperature, pH value, and import and export pressure difference have no significant influence on the transmittance of PA and SD, and the removal rate of impurity. The intercept relative molecular weight of ultrafiltration membrane has the significant influence (P < 0.01). Conclusion: The optimized ultrafiltration conditions are feasible for the preparation of Xiangdan Injection.
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PURPOSE: This study aimed to identify the effects of the sintering conditions of dental zirconia on the grain size and translucency. MATERIALS AND METHODS: Ten specimens of each of two commercial brands of zirconia (Lava and KaVo) were made and sintered under five different conditions. Microwave sintering (MS) and conventional sintering (CS) methods were used to fabricate zirconia specimens. The dwelling time was 20 minutes for MS and 20 minutes, 2, 10, and 40 hours for CS. The density and the grain size of the sintered zirconia blocks were measured. Total transmission measurements were taken using a spectrophotometer. Two-way analysis of variance model was used for the analysis and performed at a type-one error rate of 0.05. RESULTS: There was no significant difference in density between brands and sintering conditions. The mean grain size increased according to sintering conditions as follows: MS-20 min, CS-20 min, CS-2 hr, CS-10 hr, and CS-40 hr for both brands. The mean grain size ranged from 347-1,512 nm for Lava and 373-1,481 nm for KaVo. The mean light transmittance values of Lava and KaVo were 28.39-34.48% and 28.09-30.50%, respectively. CONCLUSION: Different sintering conditions resulted in differences in grain size and light transmittance. To obtain more translucent dental zirconia restorations, shorter sintering times should be considered.
Asunto(s)
Cerámica , Grano Comestible , Luz , Microondas , CirconioRESUMEN
PURPOSE: The objective of this study was to compare the light transmittance of zirconia in different thicknesses using various light curing units. MATERIALS AND METHODS: A total of 21 disc-shaped zirconia specimens (5 mm in diameter) in different thicknesses (0.3, 0.5 and 0.8 mm) were prepared. The light transmittance of the specimens under three different light-curing units (quartz tungsten halogen, light-emitting diodes and plasma arc) was compared by using a hand-held radiometer. Statistical significance was determined using two-way ANOVA (alpha=.05). RESULTS: ANOVA revealed that thickness of zirconia and light curing unit had significant effects on light transmittance (P<.001). CONCLUSION: Greater thickness of zirconia results in lower light transmittance. Light-emitting diodes light-curing units might be considered as effective as Plasma arc light-curing units or more effective than Quartz-tungsten-halogen light-curing units for polymerization of the resin-based materials.
Asunto(s)
Luz , Plasma , Polimerizacion , Polímeros , Tungsteno , CirconioRESUMEN
O presente trabalho teve como objetivo verificar a porcentagem de refletância (R) e transmitância direta (Td), e avaliar a intensidade de fluorescência (F) de 3 sistemas de resinas compostas, Filtek Supreme XT - 3M ESPE (SU), 4 Seasons - Ivoclar Vivadent (4S) e Durafill VS - Kulzer (DU), em cores indicadas para reproduzir esmalte cromático (EC), esmalte acromático (EA) e dentina (D). Como controle foram utilizados discos de esmalte e dentina humanos obtidos a partir de 5 terceiros molares extraídos. Foram confeccionados 5 espécimes por grupo a partir de matrizes metálicas (20 x 38 x 0,37 ± 0,01mm) contendo um orifício circular de 8mm. Os mesmos espécimes foram utilizados para todos os testes, sendo mantidos imersos em água filtrada. Para análise quantitativa dos resultados foi feita a média dos valores percentuais e determinada a área sob a curva de espectrofotometria entre os comprimentos de onda de 340 a 800nm. Foi usado um software gráfico para cálculo da área sob a curva no feixe de luz visível. Para a fluorescência foi utilizado um espectrofluorímetro com incidência de 390nm, sendo escolhido o comprimento de 449nm para a estatística e avaliação. A homogeneidade das variâncias foi verificada através do teste de Levene (α=0,05) e a normalidade dos resíduos de cada conjunto de dados através do teste de Shapiro-Wilk (α=0,05). Os dados foram, então, submetidos à análise de variância de um fator (material) e teste de Tukey para contraste de médias (α = 0,05). Em relação à refletância todas as resinas para EC obtiveram menores valores em comparação ao esmalte. Para Td somente a DU para EC apresentou semelhança estatística com o esmalte. Todas as resinas para dentina obtiveram menores valores de refletância em comparação à dentina, enquanto em Td somente a 4S diferiu das demais, apresentando os maiores valores. As resinas para EA apresentaram menores valores em refletância e maiores em Td em comparação ao esmalte, com exceção da ...
The objective of this study was to verify the percentage of reflectance (R) and direct transmittance (Td), and intensity of fluorescence of 3 resin composite systems, Filtek Supreme XT - 3M ESPE (SU), 4 Seasons Ivoclar Vivadent (4S) and Durafill VS - Kulzer (DU), in colors indicated to reproduce chromatic enamel (CE), achromatic enamel (AE) and dentin (D). Human enamel and dentin discs were obtained from 5 extracted molars and used as control groups. Five specimens were prepared for each group using standardized metallic matrices (20 x 38 x 0.37 ± 0.01mm) with a round perforation of 8mm. The same specimen was assayed under all tests and was maintained stored in water. For quantitative analysis of obtained data, mean values were calculated and the area below the spectrophotometry graph curve between wave lengths of 340 and 800nm (visible light) was determined using a specific software. For fluorescence test, a spectrofluorimeter with 390nm incidence was employed, so that the 449nm wave length was chosen for statistical analysis and evaluations. Variance homogeneity was verified using Levene test (α=0.05) and residual normality for each data set was analyzed by means of Shapiro-Wilk test (α=0.05). Data were submitted to statistical analysis using one-way ANOVA (material) and Tukey's test to verify differences among groups (α = 0.05). Regarding reflectance, all composites for CE obtained lower values when compared to enamel. For Td, only DU for CE presented statistically similar results to enamel. All materials for dentin obtained lower reflectance values than dentin, whereas in Td only 4S presented statistically higher values than the other composites. AE composites showed lower values in reflectance mode and higher values in T d when compared to enamel, except for DU in Td. SU for AE presented the highest values in Td and lowest in R. Among composites for CE evaluated ...