Characterization, Antimicrobial and anticancer activity of biosynthesized silver nanoparticles using Garcinia gummi-gutta (L.) Robs. leaf extracts

Garcinia gummi-gutta is commercially an important plant as its leaves and fruits contain valuable chemical components and are used for various ailments and treatments. Even though, there are minimum reports that have been seen in their exploration of this plant in the field of nanotechnology. So the present study deals with the synthesis of silver nanoparticles from the aqueous and ethanol leaf extracts of G. gummi-gutta and screening its antimicrobial and anticancer properties. Green synthesized silver nanoparticles was characterized by UV-visible (UV-vis) spectroscopy, transmission electron microscopy (TEM), fourier transforms infrared spectroscopy (FTIR) and X-ray diffraction (XRD) studies. In UV-vis spectroscopy, the surface plasmon resonance (SPR) spectrum of silver nanoparticles produced prominent peaks at 365 and 363 nm in aqueous and ethanol leaf extracts of G. gummi-gutta, respectively. Scanning electron microscopy (SEM) and XRD studies showed that the biosynthesized silver nanoparticles from aqueous and ethanol extracts of G. gummi-gutta leaves are spherical and crystalline in nature with an average size of 25 and 23 nm. FTIR spectroscopy reveals that the functional groups are responsible for the synthesis and stabilization of silver nanoparticles. The biosynthesized silver nanoparticles from both plant extracts have remarkable antibacterial and anticancer properties. Through these studies, it was found that silver nanoparticles from the ethanol leaf extract of G. gummi-gutta is more potential than silver nanoparticles from the aqueous leaf extract of G. gummi-gutta. So the present study is a novel attempt to synthesize the silver nanoparticles from this plant and elucidate its antimicrobial and anticancer potential.

Effect of Morinda citrifolia juice on the bonding strength and nanoleakage of crowns dentin / 口腔疾病防治

Objective@#To explore the effect of Morinda citrifolia juice (MCJ) combined with ethylene diamine tetraacetic acid (EDTA) on premolar bonding strength and nanoleakage and compare the results with those of the most commonly used root canal irrigation solution, sodium hypochlorite (NaClO), to provide a reference for clinical application.@*Methods@#This study was approved by the ethics review committee. Sixty-three human premolars extracted for orthodontic treatment were randomly divided into a control group (distilled water group) and 6 experimental groups according to the different rinsing solutions used after the surface enamel was removed. The experimental groups included Group A (2.5% NaClO), Group B (5.25% NaClO), Group C (6% MCJ), Group D (2.5% NaClO-17% EDTA), Group E (5.25% NaClO-17% EDTA), and Group F (6% MCJ-17% EDTA) (n = 9). After soaking in the corresponding rinsing solution for 20 minutes, they were layered and stacked on their surfaces to form 4 mm × 4 mm × 3 mm Z350 resin blocks. Six samples from each group were cut into 1 mm × 1 mm × 8 mm specimen strips for microtensile bonding strength testing. The fracture type was determined under a stereomicroscope, and the remaining 3 samples from each group were aged and cut into 1 mm thick slices for interface nanoleakage testing and scanning electron microscopy observation of the resin dentin bonding interface.@*Results@#There were significant differences in the microtensile bonding strength among the groups (P<0.05), and the control group had the highest bonding strength. Among experimental groups, Group B had the lowest bonding strength, mainly bonding interface fracture, and Group F had the highest bonding strength, mainly mixed fracture. There were significant differences in nanoleakage among all groups (P<0.05), and the control group had the lowest nanoleakage value. Among experimental groups, Group B had the highest nanoleakage, with resin protrusions being unaltered, and Group F had the lowest nanoleakage value, with resin protrusions being thick and dense.@*Conclusion@#The higher the concentration of NaClO was, the worse the bonding strength and edge sealing of the crown dentin were. The effects of root canal irrigation with MCJ and EDTA on the adhesive strength and edge sealing of crown dentin were less pronounced than those of root canal irrigation with NaClO and EDTA.

Effects of whitening dentifrices on the enamel color, surface roughness, and morphology

The aim of this study was to evaluate the whitening and abrasion effects of dentifrices containing different whitening agents on artificially stained and unstained enamel. 160 human dental enamel discs were distributed into four groups according to the type of dentifrices applied on them (n=40): Group I, non-whitening dentifrice (control group); Group II, dentifrice containing charcoal; Group III, dentifrice containing blue covarine; Group IV, dentifrice containing hydrogen peroxide. Half of the specimens in each group were immersed in coffee solution. Color measurements were evaluated from stained and unstained specimens before and after brushing by a spectrophotometer. The surface roughness of each unstained specimen was analyzed using a profilometer after the brushing and bleaching. The surface of one randomly selected specimen from each group was observed using a scanning electron microscope (SEM). Statistical analysis of the color change was performed using the Kruskal-Wallis test. The one-way ANOVA was used to evaluate surface roughness. Group III provided significantly higher recovery on ΔE00 values than other groups on the unstained enamel (p<0.05). Group IV showed significantly the highest ΔE00 values on stained enamel (p<0.05) and also Group IV showed the highest surface roughness values (p<0.05), SEM revealed a more irregular surface in groups III and IV. It can be stated that dentifrice containing blue covarine is both an effective and a safe way to provide whiter teeth with routine home tooth brushing.

El objetivo de este estudio fue evaluar los efectos de blanqueamiento y abrasión de los dentífricos que contienen diferentes agentes blanqueadores en el esmalte teñido y no teñido artificialmente. Se distribuyeron 160 discos de esmalte dental humano en cuatro grupos según el tipo de dentífrico aplicado sobre ellos (n=40): Grupo I, dentífrico no blanqueador (grupo control); Grupo II, dentífrico que contiene carbón vegetal; Grupo III, dentífrico que contiene azul; Grupo IV, dentífrico que contiene peróxido de hidrógeno. La mitad de los especímenes de cada grupo se sumergieron en una solución de café. Las mediciones de color se evaluaron a partir de especímenes teñidos y no teñidos antes y después del cepillado con un espectrofotómetro. La rugosidad de la superficie de cada muestra sin teñir se analizó utilizando un perfilómetro después del cepillado y del clareamiento. La superficie de un espécimen seleccionado al azar de cada grupo se observó utilizando un microscopio electrónico de barrido (MEB). El análisis estadístico del cambio de color se realizó utilizando la prueba de Kruskal-Wallis. Se utilizó el ANOVA para evaluar la rugosidad de la superficie. El grupo III proporcionó una recuperación significativamente mayor en los valores de ΔE00 que otros grupos en el esmalte no teñido (p<0,05). El Grupo IV mostró significativamente los valores más altos de ΔE00 en el esmalte teñido (p<0.05) y también el Grupo IV mostró los valores más altos de rugosidad superficial (p<0.05), el análisis en MEB reveló una superficie más irregular en los grupos III y IV. Se puede afirmar que el dentífrico que contiene azul es una forma efectiva y segura de proporcionar dientes más claros con el cepillado de rutina en el hogar.

A Novel Approach for the Treatment of Hypertension: Gastroretentive Microballoons of Atenolol

The formulation of atenolol-loaded microballoons involved the use of Eudragit RS 100, HPMC K4 M as a polymer, and span 80 as a surfactant. The microballoons were prepared by an emulsion solvent diffusion (non-aqueous) using liquid paraffin, methanol, and dichloromethane as a processing medium. The Box-Behnken design was utilized to get optimized formulation using a concentration of HPMC K4 M (A), Concentration of Eudragit RS 100 (B), Concentration of surfactant (C), and stirring speed (D) as an independent parameter while, Particle size (Y1), entrapment efficiency (Y2) and %buoyancy (Y3) using as a dependent parameter. For the optimised formulation, the mean particle size was 85.878 ± 1.063 ?m, entrapment efficiency was 92.26 ± 1.65%, and buoyancy was 89.19 ± 1.48% found. An image of the formulation taken using a scanning electron microscope (SEM) reveals discrete particles with a smooth surface texture, a hollow interior, a spherical shape, and a particle size of less than 200 ?m. The FTIR study confirms there was no interaction between the drug and excipients. The in-vitro drug release study found that atenolol-loaded microballoons released the drug for up to 12 hours as compared to the pure drug. This was due to increasing the gastric residence time and absorption area in the stomach. The drug release kinetic study reveals that it follows the Higuchi model and the drug release mechanism was type II transport which was obtained from the Korsmeyer Peppas model. The stability study shows that there is no significant change in the optimized microballoons for 30 days as per ICH guidelines.

The effect of sonic activated device used for different time on intracanal smear layer removal: An SEM analysis / 口腔医学

Objective @#To observe the clearance of smear layer on the root canal wall in different action time by scanning electron microscope (SEM), and to determine the optimal amount of time using sonically activated irrigation to wash root canal in clinic. @*Methods@# Fifty-six ex vivo human anterior teeth with single straight root canal were selected. After routine mechanical preparation, they were divided into two experimental groups according to different irrigating agents: saline group and EDTA group. Each group was assisted by VDW sonic activation EDDY. The saline group was divided into three subgroups according to the irrigating time: 5 s, 30 s and 50 s; EDTA group was divided into six subgroups according to the irrigating time: 5 s, 10 s, 20 s, 30 s, 40 s and 50 s. The control group did not undergo root canal irrigation. After irrigation, the root was cut longitudinally. The smear layer of crown, middle and apical of root canal wall was observed by SEM.@* Results@# After irrigating for 30 seconds, there was a significant difference between the normal saline group and the control group and the 5 second group (P<0.05), and there was no difference in the middle and apical part (P>0.05). After 50 seconds, there was a significant difference in the score of the smear layer between the apical area and the other groups (P<0.05). After irrigating for 5 seconds or 10 seconds in EDTA group, there was a significant difference between the scores of the crown and middle area of the root canal and the control group (P<0.05), and there was no significant difference in the apical area (P>0.05). There was a significant difference between the 20-40 second group and the first two groups (P<0.05). There was a significant difference between the 50 second group and the other groups (P<0.05). Comparing the cleaning effect on the smear layer after 50 seconds of irrigating between the two experimental groups, the whole root canal showed significant statistical difference (P<0.05). @*Conclusion @#The EDTA-assisted sonic activated device used for 50 seconds has the best cleaning effect.

Mechanism of pterostilbene reducing oxidative damage in endothelial cells in mouse hepatic sinus / 中国药理学通报

Aim To explore the mechanism of the natural phenolic compound pterostilbene(PTE)in the protection of liver ischemic/reperfusion. Methods A total of 40 C57 mice were divided into control group,model group,drug delivery group and treatment group and a 70% liver ischemic/reperfusion(ischemic 60 min)model was established,then primary LSECs were isolated by perfusion and digestion. Hepatic structural disruption was observed by HE staining. The ultrastructure of hepatic sinus endothelial cells was observed by transmission electron microscopy(TEM). The structure of LSECs fenestrae was observed by scanning electron microscopy(SEM). The expression level of heme oxygenase 1(HO-1)in LSECs was detected by Western blot. Results HE staining showed that PTE protected against hepatic ischemic injury. TEM observed that PTE had a protective effect on hepatic sinus endothelial cells,and the number of LSECs fenestrae in the blank control group was larger and the number of fenestrae in the liver I/R model group was reduced. The number of LSECs fenestrae in the liver I/R model group treated with PTE increased compared with the untreated liver I/R model group. Western blot result showed that PTE was able to induce HO-1 expression in LSECs. Conclusions PTE alleviates oxidative damage of endothelial cells in mouse hepatic sinus by inducing HO-1expression,and protects the liver from ischemia/reperfusion injury.

The removal of three kinds of occlusal veneers by Er: Yag laser / 华西口腔医学杂志

OBJECTIVES@#This study aimed to remove occlusal veneers of varied thicknesses and compositions by Er:Yag laser in vitro and analyze the interfacial microstructure between veneers and tooth that irradiated by laser, by which experimental evidence could be provided to support the non-invasive removal of occlusal veneerby laser.@*METHODS@#Fresh mandibular premolars extracted for orthodontic requirements were collected for tooth preparation. Three kinds of ceramic materials (Vita Suprinity, Vita Mark Ⅱ, and Upcera Hyramic) were selected to fabricate occlusal veneer with different thicknesses (1.0, 1.5, and 2.0 mm). One week later, Er:Yag laser (2.5 W and 3.5 W) was used to irradiate and remove the occlusal veneer and recorded the timespan. After the removal operation, the micro-morphologies of samples were examined by scanning electron microscope.@*RESULTS@#Upcera Hyramic veneer failed to be removed (>20 min); the operation span at 2.5 W, Vita Suprinity (96.0 s±16.0 s) was longer than Vita MarkⅡ(84.5 s±19.5 s) in the 1.0 mm group (P<0.05), and Vita Suprinity (246.5 s±13.5 s) was longer than Vita MarkⅡ(170.0 s±14.0 s) in the 1.5 mm group (P<0.05). At 3.5 W, Vita Suprinity (381.0 s±24.0 s) was longer than Vita MarkⅡ(341.5 s±26.5 s) in the 2.0 mm group.@*CONCLUSIONS@#Increasing laser power could shorten the operation span and facilitate the removal of occlusal veneers with the same thickness and composition. The occlusal veneer was sustained when insufficient laser power was applied. With the same laser power and ceramic thickness, laser penetration could interfere with the integral of the ceramic structure when the laser interacted with the bonding layer. With the same ceramic composition and laser power, the operation span and laser power increased with the thickness of the occlusal veneer. However, the laser was incapable of removing occlusal resin veneer directly.

Clinical study of different composite resin systems in Class I cavities (an 18-month randomized clinical trial) / Estudo clínico de diferentes sistemas de resina composta em cavidades de Classe I (um ensaio clínico randomizado de 18 meses)

Objective: this double-blind randomized clinical trial evaluate the clinical performance of Thermo-Viscous Bulk Fill composite, Self-Adhesive Flowable composite, and Filtek Bulk Fill Composites restorations in Class I cavities over a period of 18 months. Material and Methods: twenty individuals between the ages of 30 and 45 participated in this research. Each patient should have at least three occlusal Class I carious lesions on their molars. They were dispersed at random, with n=20 teeth representing each tested material. Group I (Futurabond M+ and VisCalor Bulk Fill which heated in a viscolar dispenser at 68 °C for 30s and placed in a 4 mm thickness), Group II (Fusio Liquid Dentin self-adhesive composite which put in a thin layer (1mm increment)), and Group III (Single Bond Universal and Filtek Bulk Fill Posterior composite which applied in 4 mm thickness without heating). Using (USPHS) criteria, all restorations were assessed clinically at baseline, 6 months, 12 months, and 18 months. Using an inverse replica, the marginal seal of the investigated restorations was further evaluated under SEM. Statistical analysis was performed with Chi-square test for all USPH parameters. Results: the three tested groups recorded a one hundred percent retention rate after 18 months follow up period. Concerning marginal adaptation, marginal discoloration, anatomical form, surface texture, and color matching, there was a significant difference (p˂0.05) between the three tested groups after 12 & 18 months. After 12 & 18 months, SEM analysis of the marginal seal revealed a statistically significant difference between the three groups. Conclusion: Bulk fill resin composite restorations showed satisfactory acceptable clinical performance after 18 months of clinical service compared to self-adhesive flowable composites, and Viscalor Bulk Fill composite demonstrated excellent results with considerable changes in marginal integrity as a consequence of thermal viscous technology and increased adaptability of restorations toward cavity walls and margins (AU)

Objetivo: este ensaio clínico randomizado duplo-cego avaliou o desempenho clínico de restaurações de resina Bulk Fill Termo-Viscosa, resina autoadesiva Flowable e Filtek Bulk Fill Composites em cavidades Classe I durante um período de 18 meses. Material e Métodos: 20 indivíduos com idade entre 30 e 45 anos participaram da pesquisa. Cada paciente deveria ter pelo menos três lesões de cárie oclusais de Classe I nos molares. Eles foram divididos aleatoriamente, com n=20 dentes representando cada material testado. Grupo I (Futurabond M+ e VisCalor Bulk Fill aquecido em dispensador viscolar a 68 °C por 30s e colocado em uma espessura de 4 mm), Grupo II (resina composta autoadesiva Fusio Liquid Dentin colocada em uma camada fina (incremento de 1 mm)) e Grupo III (resina composta Single Bond Universal e Filtek Bulk Fill Posterior aplicado em espessura de 4 mm sem aquecimento). Usando os critérios (USPHS), todas as restaurações foram avaliadas clinicamente no início, 6 meses, 12 meses e 18 meses. Usando uma réplica inversa, o selamento marginal das restaurações investigadas foi avaliado em MEV. A análise estatística foi realizada com o teste qui-quadrado para todos os parâmetros USPH. Resultados: os três grupos testados registraram uma taxa de retenção de cem por cento após um período de acompanhamento de 18 meses. Em relação à adaptação marginal, descoloração marginal, forma anatômica, textura da superfície e combinação de cores, houve uma diferença significativa (p˂0,05) entre os três grupos testados após 12 e 18 meses. Após 12 e 18 meses, a análise SEM do selamento marginal revelou uma diferença estatisticamente significativa entre os três grupos. Conclusão: as restaurações de resina composta Bulk Fill apresentaram desempenho clínico aceitável satisfatório após 18 meses de atendimento clínico em comparação com as resinas compostas fluidas autoadesivas, e a resina composta Viscalor Bulk Fill demonstrou excelentes resultados com mudanças consideráveis na integridade marginal, como consequência da tecnologia viscosa térmica e maior adaptabilidade de restaurações nas paredes e margens da cavidade (AU)

How does radiotherapy affect the adhesion of universal adhesive to enamel and dentin? A qualitative and quantitative analysis? / Efecto de la radioterapia a la adhesión del adhesivo universal al esmalte y dentina? Un análisis cualitativo y cuantitativo?

Abstract This study investigated the shear bond strength (SBS) of a universal adhesive to enamel/dentin; 1) that had undergone radiotherapy (RT) and 2) that were readily restored and had undergone RT. Enamel and dentin surfaces were obtained from 90 intact human molars. They were randomly divided into six groups according to the presence and timing of irradiation (RT0:no radiotherapy/control, RT1:RT before restoration, RT2:RT after restoration groups) and adhesive application modes (etch&rinse/ER, self-etch/SE)(n=15). A universal adhesive and resin composites were applied. The radiotherapy protocol was conducted with 60 Gy. The SBS test was subjected (1mm/min) and failure type analysis was performed. The resin-enamel/dentin interfaces were examined. Data were statistically analyzed. For enamel and dentin, the presence and timing of irradiation did not significantly influence the SBS values (p>0.05). For enamel, significantly higher SBS values were obtained using etch&rinse mode than self-etch mode (p<0.05). The predominant failure was mixed type. Loss of enamel prisms and obliterated irregular dentinal tubules were found for the radiotherapy-treated specimens. Resin tags were clearer in the irradiated enamel treated with ER than SE. Irradiation with different timings did not influence the bond strength to enamel and dentin, negatively. Irrespective of radiotherapy, the etch&rinse mode caused higher bond strength to enamel than self-etch mode.

Resumen Este estudio investigó la fuerza de unión al cizallamiento (SBS) de un adhesivo universal al esmalte/dentina en piezas que se habían sometido a radioterapia (RT). Se obtuvieron superficies de esmalte y dentina de 90 molares humanos intactos. Se dividieron aleatoriamente en seis grupos según la presencia y el momento de la irradiación (RT0: sin radioterapia/control, RT1: RT antes de la restauración, RT2: RT después de la restauración considerando los modos de aplicación del adhesivo (n=15). Se aplicó un adhesivo universal y resinas compuestas. El protocolo de radioterapia se realizó con 60 Gy. Se sometió a la prueba adhesiva (1mm/min) y se realizó análisis del tipo de falla. Se examinaron las interfases resina-esmalte/dentina. Los datos fueron analizados estadísticamente. Para el esmalte y la dentina, la presencia y el momento de la irradiación no influyeron significativamente en los valores adhesivos (p>0,05). Para el esmalte, se obtuvieron valores adhesivos significativamente más altos utilizando el modo de grabado y enjuague que el modo de autograbado (p<0,05). La falla predominante fue de tipo mixto. Se encontró pérdida de prismas de esmalte y túbulos dentinarios irregulares obliterados en las muestras tratadas con radioterapia. La irradiación con diferentes tiempos no influyó negativamente en la fuerza de unión al esmalte ni a la dentina. Independientemente de la radioterapia, el modo de grabado ácido y enjuague provocó una mayor fuerza de adhesión al esmalte que el modo de autograbado.

Evaluation Of Sealing Ability Of Biodentine, MTA Angelus And Zirconia-Reinforced Glass Ionomer Cement For Repairing Furcation Perforations : An In Vitro Study

Background:Background and objective: One of the unfavourable outcomes of endodontic treatment is furcal perforation. Materials such as MTA-Angelus, Biodentine and Zirconomer have been recommended for the repair of furcal perforations.In this study we compared the sealing ability of MTA-Angelus, Biodentine and Zirconia-reinforced GIC in furcal perforations using dye penetration method. Material And Methods:Access cavities were prepared in extracted mandibular molars (n= 40) using round bur in a high speed hand pieceunder water coolant. Perforations were made in the centre of furcation region using 2mm round bur.The teeth were randomly divided into 4 groups based on the material used to seal the perforation: Group I(n= 12) = MTA –Angelus , Group II (n=12)= Biodentine, Group III(n=12) = Zirconomer , Group IV (n= 4) = left unsealed (negative control group).Leakage at the repaired site was then evaluated using methylene blue dye penetration technique under stereomicroscope and data was statistically analyzed.Result:Minimum dye penetration was observed in biodentine followed by MTA, Zirconomer and control group. The results was not statistically significant (p= .08). Conclusion:According to this study, biodentine showed best of the three materials used for furcation repair.

Effects of different concentrations of sodium hypochlorite on dentine adhesion and the recovery application of sodium erythorbate / 中南大学学报(医学版)

OBJECTIVES@#Root canal therapy is the most effective and common method for pulpitis and periapical periodontitis. During the root canal preparation, chemical irrigation plays a key role. However, sodium hypochlorite (NaOCl), the widely used irrigation fluid, may impact the bonding strength between dentin and restorative material meanwhile sterilization and dissolving. Therefore, it's important to explore the influence of NaOCl on the adhesion between dentin and restoration materials to ensure clinical efficacy. This study aims to explore the effect of NaOCl on dentine adhesion and evaluate the effect of dentine adhesion induced by sodium erythorbate (ERY), and to provide clinical guidance on dentin bonding after root canal therapy.@*METHODS@#Seventy freshly complete extracted human third molars aged 18-33 years old, without caries and restorations were selected. A diamond saw was used under running water to achieve dentine fragments which were divided into 10 groups with 14 fragments in each group: 2 control [deionized water (DW)±10% ERY] and 8 experimental groups (0.5%, 1%, 2.5%, and 5.25% NaOCl±10% ERY). The dentine specimens in the control group (treated with DW) and the experimental groups (treated with 0.5% NaOCl, 1% NaOCl, 2.5% NaOCl, and 5.25% NaOCl) were immersed for 20 min using corresponding solutions which were renewed every 5 min. The other 5 groups were immersed in 10% ERY for 5 min after an initial washing with DW for 1 min. Then, we selected 4 dentine fragments from all 14 fragments in each group and the numbers and diameters of opening dentinal tubules were observed under scanning electron microscope (SEM). The other 10 dentine fragments from each group were used to make adhesive samples by using self-etch adhesive wand composite resin. All the above adhesive samples were sectioned perpendicular to the bonded interface into 20 slabs with a cross-sectional area of 1 mm×1 mm using a diamond saw under the cooling water, and then the morphology of 10 slabs in each group's bonding interface was observed from aspects of formation of resin tags, depth of tags in dentin, and formation of hybrid layer under SEM. The other 10 slabs of each group's microtensile bond strength and failure modes were also analyzed.@*RESULTS@#Among the 0.5% NaOCl, 1% NaOCl, 2.5% NaOCl, and 5.25% NaOCl groups, the number and diameter of patent dentinal tubules gradually increased with the rise of concentration of NaOCl solution (all P<0.05). Among the DW, 0.5% NaOCl, 1% NaOCl, 2.5% NaOCl, and 5.25% NaOCl groups, the number and diameter of patent dentinal tubules increased after using ERY, but without significant difference (all P>0.05). Among the DW, 0.5% NaOCl, 1% NaOCl, and 2.5% NaOCl groups, the scores of formation of resin tags under SEM gradually increased with the increase of concentration of NaOCl solution, while the score in the 5.25% NaOCl group decreased significantly compared with the score of the 2.5% NaOCl group (P<0.05). There was no significant difference between using 10% ERY groups and without using 10% ERY groups (all P>0.05). The scores of length of the tags under SEM in the 5.25% NaOCl group was significantly higher than the scores of DW, 0.5% NaOCl, and 1% NaOCl groups (all P<0.05), and it was also higher than the score of the 2.5% NaOCl group, but without significant difference (P>0.05). There was no significant difference between using 10% ERY groups and without using 10% ERY groups (P>0.05). The scores of formation of hybrid layer under SEM in the 2.5% NaOCl and 5.25% NaOCl groups significantly decreased compared with the score of the DW group (all P<0.05). There were significant differences between the 2.5% NaOCl±10% ERY groups and between the 5.25% NaOCl±10% ERY groups (all P<0.05). Microtensile bond strength was greater in the 0.5% NaOCl, 1% NaOCl, and 2.5% NaOCl groups, but lower in the 5.25% NaOCl group than that in the DW group (all P<0.05). There were significant differences between the 2.5% NaOCl±10% ERY groups and between the 5.25% NaOCl±10% ERY groups (all P<0.05). The incidence of type "Adhesive" of failure modes in the 5.25% NaOCl group was significantly higher than that in other groups (all P<0.05), while the incidence of type "Adhesive" in the 5.25% NaOCl+10% ERY group was lower than that in the 5.25% NaOCl group (P<0.05).@*CONCLUSIONS@#The bonding strength to dentine increases with the increase of NaOCl concentration when the concentration lower than 2.5%; whereas it is decreased at a higher concentration (such as 5.25%). 10% ERY has a definite recovery effect on attenuated bonding strength to 5.25% NaOCl-treated dentine.

In vitro anti-Candida activity of Melaleuca cajuputi extracts

Aims@#The rise of drug-resistant infectious diseases worldwide has spurred experts' interest in developing safe and effective alternative medicine. Melaleuca cajuputi extracts have been shown to exhibit antimicrobial activity in vitro against various bacterial species. This study evaluated the antimicrobial activity of local M. cajuputi leaf extracts (MCEs) against Candida albicans.@*Methodology and results@#Phytoconstituents of aqueous and ethanolic MCEs were screened conventionally using chemical tests. Broth microdilution assay and scanning electron microscope (SEM) were performed to study the anti-Candida activity of the extracts. Both MCEs contained terpenoids, phenols, flavonoids and tannins. Aqueous and ethanolic MCEs showed good fungicidal activity against the tested organism with minimum inhibitory concentration (MIC) values of 50 mg/mL and 25 mg/mL, respectively and a minimum fungicidal concentration (MFC) to MIC ratio of less or equal to 2. Scanning electron micrographs revealed yeast cell surface morphology alterations when treated with both MCEs at 1× MIC.@*Conclusion, significance and impact of study@#In conclusion, MCEs have anti-Candida properties and thus, M. cajuputi extract could be an excellent potential source of natural antimicrobial agents for disease remedies.

Evaluation of Inspection Efficiency of Diatom Artificial Intelligence Search System Based on Scanning Electron Microscope / 法医学杂志

OBJECTIVES@#To explore the application values of diatom artificial intelligence (AI) search system in the diagnosis of drowning.@*METHODS@#The liver and kidney tissues of 12 drowned corpses were taken and were performed with the diatom test, the view images were obtained by scanning electron microscopy (SEM). Diatom detection and forensic expert manual identification were carried out under the thresholds of 0.5, 0.7 and 0.9 of the diatom AI search system, respectively. Diatom recall rate, precision rate and image exclusion rate were used to detect and compare the efficiency of diatom AI search system.@*RESULTS@#There was no statistical difference between the number of diatoms detected in the target marked by the diatom AI search system and the number of diatoms identified manually (P>0.05); the recall rates of the diatom AI search system were statistically different under different thresholds (P<0.05); the precision rates of the diatom AI system were statistically different under different thresholds(P<0.05), and the highest precision rate was 53.15%; the image exclusion rates of the diatom AI search system were statistically different under different thresholds (P<0.05), and the highest image exclusion rate was 99.72%. For the same sample, the time taken by the diatom AI search system to identify diatoms was only 1/7 of that of manual identification.@*CONCLUSIONS@#Diatom AI search system has a good application prospect in drowning cases. Its automatic diatom search ability is equal to that of experienced forensic experts, and it can greatly reduce the workload of manual observation of images.

Construction and Application of YOLOv3-Based Diatom Identification Model of Scanning Electron Microscope Images / 法医学杂志

OBJECTIVES@#To construct a YOLOv3-based model for diatom identification in scanning electron microscope images, explore the application performance in practical cases and discuss the advantages of this model.@*METHODS@#A total of 25 000 scanning electron microscopy images were collected at 1 500× as an initial image set, and input into the YOLOv3 network to train the identification model after experts' annotation and image processing. Diatom scanning electron microscopy images of lung, liver and kidney tissues taken from 8 drowning cases were identified by this model under the threshold of 0.4, 0.6 and 0.8 respectively, and were also identified by experts manually. The application performance of this model was evaluated through the recognition speed, recall rate and precision rate.@*RESULTS@#The mean average precision of the model in the validation set and test set was 94.8% and 94.3%, respectively, and the average recall rate was 81.2% and 81.5%, respectively. The recognition speed of the model is more than 9 times faster than that of manual recognition. Under the threshold of 0.4, the mean recall rate and precision rate of diatoms in lung tissues were 89.6% and 87.8%, respectively. The overall recall rate in liver and kidney tissues was 100% and the precision rate was less than 5%. As the threshold increased, the recall rate in all tissues decreased and the precision rate increased. The F1 score of the model in lung tissues decreased with the increase of threshold, while the F1 score in liver and kidney tissues with the increase of threshold.@*CONCLUSIONS@#The YOLOv3-based diatom electron microscope images automatic identification model works at a rapid speed and shows high recall rates in all tissues and high precision rates in lung tissues under an appropriate threshold. The identification model greatly reduces the workload of manual recognition, and has a good application prospect.

Effects of concentrated sulfuric acid etching durations on the shear bond strength between polyether-ketone-ketone and dentin / 口腔疾病防治

Objective@# To study the effects of different concentrated sulfuric acid etching durations on the shear bond strength between polyether-ketone-ketone (PEKK) and dentin, providing a scientific basis for the clinical bonding procedures of PEKK prosthesis.@*Methods@# Forty-four PEKK specimens were prepared and randomly divided into four groups: group A was the control group, which was only polished with abrasive papers, group B, group C and group D were experimental groups, which were etched by 98% concentrated sulfuric acid for 5 s, 30 s and 60 s, respectively. In addition, one sample was randomly selected from each group, and the profile was prepared by a slow cutting machine. The surface morphology of the profile was observed under SEM. After the four groups of specimens and dentin were bonded by resin, they were soaked in distilled water at 37 ℃ for 24 h. After the shear bonding strengths were measured, the fracture interfaces of the specimens were examined by the scanning electron microscopy and stereomicroscopy, and failure models of bonding were analyzed. @*Results@#After acid etching treatments, the cross-sectional images in group B presented uniform spongy shapes, while the cross-sectional images in group C and group D showed destructive pore structures. The shear bond strengths of group B (16.84 ± 1.84) MPa, group C (12.33 ± 1.22) MPa and group D (6.44 ± 1.18) MPa were higher than that of group A (3.99 ± 1.06) MPa (P < 0.05). The highest shear bond strength was observed in group B (16.84 ± 1.84) MPa. @*Conclusion @#The surface treatment of 98% sulfuric acid etching for 5 s manifested the best bond strength between PEKK and dentin.

Skin Ultrastructure and the Changes of HIF-2α, H-FABP Expression in the Myocardium of Electric Shock Death Rats / 法医学杂志

Objective To observe the skin ultrastructure change of electric shock death rats and to test the expression changes of hypoxia-inducible factor-2α （HIF-2α） and heart type-fatty acid-binding protein （H-FABP） of myocardial cells, in order to provide basis for forensic identification of electric shock death. Methods The electric shock model of rats was established. The 72 rats were randomly divided into control group, electric shock death group and postmortem electric shock group. Each group was divided into three subgroups, immediate （0 min）, 30 min and 60 min after death. The skin changes of rats were observed by HE staining, the changes of skin ultrastructure were observed by scanning electron microscopy, and the expression of HIF-2α and H-FABP in rats myocardium was tested by immunohistochemical staining. Results The skin in the electric shock death group and postmortem electric shock group had no significant difference through the naked eye or by HE staining. Under the scanning electron microscope, a large number of cellular debris, cells with unclear boundaries, withered cracks, circular or elliptical holes scattered on the cell surface and irregular edges were observed. A large number of spherical foreign body particles were observed. Compared with the control group, the expression of HIF-2α in all electric shock death subgroups increased, reaching the peak immediately after death. In the postmortem electric shock group, HIF-2α expression only increased immediately after death, but was lower than that of electric shock death group （P<0.05）. Compared with the control group, the expression of H-FABP in all subgroups of electric shock death group and postmortem electric shock group significantly decreased. The expression of H-FABP in all subgroups of electric shock death group was lower than that of the postmortem electric shock group （P<0.05）. Conclusion Electric shock can increase HIF-2α expression and decrease H-FABP expression in the myocardium, which may be of forensic significance for the determination of electric shock death and identification of antemortem and postmortem electric shock.

The architecture of alveolar capillaries in the lungs of bactrian camels (Camelus bactrianus) / Arquitectura de los capilares alveolares de pulmones de camellos bactrianos (Camelus bactrianus)

SUMMARY: The Bactrian camel, which is native to China and Mongolia, is large in size and is an even-toed ungulate species. The double humps on the Bactrian camel back differentiate it from the dromedary camel, which has a single hump. This species has adapted to unsuitable conditions (lack of food and water) in the Gobi Desert and is advanced in unique anatomical and physiological characteristics during a prolonged evolution period. Several studies have been conducted on the anatomical features of the Bactrian camel, but none have given attention to the alveolar capillaries of the Bactrian camel lung. Therefore, the current study aims to explore the architecture of the alveolar capillary in the Bactrian camel lung and further explain the mechanism of blood flow in its lung. The current study extracted and examined the architecture of the alveolar capillary in the lung of the Bactrian camel (Camelus bactrianus) and further explained the mechanism of blood flow by performing lung casting and replica scanning electron microscopy methods. The reports showed that the resources of the alveolar-capillary originated from the capillaries of the subpleural space or interlobular septulum, sometimes originating from the precapillary arterioles or directly from the terminal arterioles. The alveolar capillaries anastomosed and formed a single layer of dense, basket-like network surrounding the alveolus. The mash diameter of the alveolar-capillary network was larger than that of the capillary, and the appearance of the mash was oval and elliptical. Many of the collapsed alveolar-capillary networks were found in the alveolar microvascular architecture in the lung of the Bactrian camel. The study found that, due to many collapsed alveoli in the Bactrian camel lung, the disproportional pressure between the pulmonary alveoli induced less imbalance of blood flow in the alveolar capillary, which affected the gas exchange efficiency. Therefore, the function of the anastomosing capillary branch was likely to regulate the blood flow between the alveolar-capillary network.

RESUMEN: El camello bactriano, es originario de China y Mongolia, es de gran tamaño y es una especie de ungulado de dedos pares. Las dobles jorobas del lomo del camello bactriano lo diferencian del dromedario, que tiene una sola joroba. Esta especie se ha adaptado a condiciones inadecuadas (falta de alimento y agua) en el desierto de Gobi y ha avanzado en características anatómicas y fisiológicas únicas durante un período de evolución prolongado. Se han realizado varios estudios sobre las características anatómicas del camello bactriano, pero ninguno ha prestado atención a los capilares alveolares del pulmón de este animal. Por lo tanto, el presente estudio tuvo como objetivo principal explorar la arquitectura del capilar alveolar en el pulmón del camello bactriano y explicar el mecanismo del flujo sanguíneo. A partir de nuestro trabajo se examinó la arquitectura del capilar alveolar en el pulmón del camello bactriano (Camelus bactrianus) mediante la realización de métodos de microscopía electrónica de barrido y escaneo pulmonar. Los informes mostraron que los recursos del alvéolo-capilar se originaban en los capilares del espacio subpleural o del tabique interlobulillar y a veces se originaban en las arteriolas precapilares o directamente en las arteriolas terminales. Los capilares alveolares se anastomosaban y formaban una densa red de capa única en forma de cesta que rodeaba el alvéolo. El diámetro del macerado de la red alveolar-capilar era mayor que el del capilar y el aspecto del macerado era ovalado y elíptico. Muchas de las redes alvéolo-capilares colapsadas se encontraron en la arquitectura microvascular alveolar en el pulmón del camello bactriano. El estudio encontró que, muchos alvéolos colapsados en el pulmón del camello bactriano, la presión desproporcionada entre los alvéolos pulmonares inducía un menor desequilibrio del flujo sanguíneo en el capilar alveolar, lo que afectaba la eficiencia del intercambio de gases. Por lo tanto, la función de la rama capilar anastomosante probablemente regularía el flujo sanguíneo entre la red alveolar-capilar.

Experimental study on central location ability and clearance rate of three nickel-titanium instruments for root canal retreatment / 口腔疾病防治

Objective@# Comparision of the central location ability and clearance rate of ProTaper retreatment, Fengdu O-file and M3-RT three kinds of nickel-titanium instruments and hand stainless instruments K-file, H-file. Observe the form of the root canal wall. To provide experimental basis and reference for the clinical application of nickel-titanium instruments for root canal retreatment.@*Methods @#40 simulated resin blocks with the same specification were randomly divided into four groups (n=10). Each group was separately prepared with hand stainless instruments K-file and H-file (group A1), ProTaper retreatment (group B1), Fengdu O-file (group C1), and M3-RT (group D1). Using scanner to obtain the pre- and post-operative images and overlapping the images through Photoshop. Measuring the root canal inner and outer wall resin removal with Image J, compared the central location ability of the four group. A total of 60 mandibular single canal premolars extracted due to orthodontics were collected. The teeth were randomly divided into four groups (n=15) after filling the root canal. Use hand stainless instruments K-file,H-file(group A2), ProTaper retreatment (group B2), Fengdu O-file(group C2) , M3-RT(group D2) to remove the filling materials. The roots were longitudinally sectioned, and the image of the root surface was photographed under the 10 × magnification microscope. The software was used to trace the area of the root canal wall and residual root filling, and the root filling clearance rate of each group was calculated. Two teeth were randomly selected in each group and observed under scanning electron microscope.@*Results@#Within 9 mm from the root tip hole, the central location ability of group B1, C1, D1 was better than that of group A1(P ＜ 0.05). At 4 mm from the root tip hole, group D1 has the best central location ability(P ＜ 0.05). There was no difference of the four instruments at a distance of 10 mm from the root tip hole（P ＞ 0.05）. There were various degree of filling material remained in the root canal after the four groups of instruments for retreatment canal preparation. There was no significant difference between group B2, C2, D2（P ＞ 0.05）, and both were higher than group A2(P ＜ 0.05). Scanning electron microscope observation results shown that the root canal wall prepared by group B2, C2, D2 was more smooth and continuous than group A2, and the residual filling material was less. @*Conclusion @#The central location ability of three kinds of nickel-titanium root canal retreatment instruments were significantly better than that of hand stainless instruments. ProTaper retreatment, Fengdu O-file and M3-RT three kinds of nickel-titanium root canal retreatment instruments showed good performance, the central location ability of M3-RT was slightly better. Nickel-titanium root canal retreatment instruments are more efficient than traditional hand stainless instruments in removing root fillings and the root canal wall after preparation is smoother and has good continuity.

Structure and mechanical properties of high- and low-weight-bearing areas of hip cartilage at micro and nano levels / 中国组织工程研究

BACKGROUND: Articular cartilage has a high-weight-bearing area and a low-weight-bearing area. There are different macroscopic elastic moduli in the two regions, but the modulus of the two areas at the micro and nano levels is unknown. Such information is important for further understanding of cartilage micro and nano mechanics. Moreover, the micro and nano structures of the two areas, which influence the cartilage mechanical properties, should be discussed. OBJECTIVE: To investigate the mechanical properties and structure of high- and low-weight-bearing areas of the hip articular cartilage at the micro and nano levels. METHODS: Normal porcine femoral head cartilage was used. Atomic force microscopy with a spherical tip of 5 µm in diameter was used to measure the microscale compressive elastic modulus of different weight-bearing areas of the cartilage. The nanoscale compressive elastic modulus, nano structure, and collagen fiber diameter were measured using a ScanAsyst-Air probe with a radius of curvature of 5 nm. Scanning electron microscopy was employed to identify the microstructure of different weight-bearing areas of the cartilage. RESULTS AND CONCLUSION: The microscale elastic modulus of the high-weight-bearing area of the femoral head cartilage was (433.05±146.52) kPa, and the microscale elastic modulus of the low-weight-bearing area was (331.19±84.88) kPa. The nanoscale elastic modulus of the high- and low-weight-bearing areas of the femoral head cartilage was (1.24±0.42) GPa and (1.28±0.41) GPa, respectively. While no statistically significant differences were found in the elastic modulus of collagen fibers at the nano level (P=0.846 2). The collagen fibers of the high-weight-bearing area arranged more regularly than those of the low-weight-bearing area at the micro level. No significant differences between collagen fiber diameter of the two areas at the nano level were observed (P=0.926 4). To conclude, the collagen fibers of the high-weight-bearing area are cross-linked more regularly than those of low-weight-bearing area. Therefore, the compressive elastic modulus of the high-weight-bearing area at the micro level is significantly higher than that of the low-weight-bearing area, which is consistent with the macroscopic compressive elastic modulus trend. However, high-weight-bearing has no impact on individual collagen fibers at the nano level.

Cleaning efficacy of two kinds of mechanical nickel-titanium instruments in preparation of severely curved root canals: A scanning electron microscopic study / 中国组织工程研究

BACKGROUND: The preparation and cleaning of severely curved root canal is the difficult point of root canal treatment. A large number of smear layer will be produced in the process of root canal preparation. Removing effectively these debris and smear layer will be conducive to improving the success rate and longterm effect of severely curved root canal treatment. OBJECTIVE: To explore the cleaning efficacy of Twisted File and ProTaper file combined with chemical preparation on smear layer of severely curved root canal by scanning electron microscope. METHODS: Twenty clinically extracted mandibular molars with severely curved root canals were collected and randomly divided into two groups: Twisted File group and ProTaper group. The root canals were prepared by Twisted file and ProTaper Ni-Ti file, respectively. They were prepared by chemical method with 3% NaClO and 17% EDTA. After preparation, the root canals were split longitudinally and the cleaning efficacy of smear layer of coronal, middle and apical thirds was observed by scanning electron microscope. RESULTS AND CONCLUSION: (1) The images of scanning electron microscope showed that the dentinal tubules of root canal coronal thirds in the ProTaper group and Twisted file group were completely open, almost without smear layer. Dentinal tubules of middle thirds were also open, and simply part of them were covered by smear layer. However, dentinal tubules of apical thirds had few and no obvious opening, and was covered by a large number of smear layer. (2) In Twisted file group, the scores of smear layer at root canal apical thirds were higher than coronal and middle thirds (P 0.05). (3) The results showed that the chemo-mechanical preparation with Twisted File and ProTaper could remove effectively the debris and smear layer in the root canal walls of coronal and middle thirds of the severely curved crown, but the removal effect on apical thirds and dentin tubules was not good.