Water quality in the Lachuá Ecoregion Landscape: Comparing streams from Forest, Milpa, and an Oil Palm plantation / Calidad del agua en el paisaje de la Ecorregión Lachuá: Comparando arroyos en bosques, milpa y palma africana

The hydrological network in the Lachuá Ecoregion (EL), Alta Verapaz, Guatemala, hosts high levels of biodiversity and supplies water to 44 Mayan communities. Despite this critical fact, this network has been threatened by scarcely monitored industrial activities including the rapidly expanding oil palm monoculture (Elaeis guineensisJacq). Regardless of Lachua's freshwaters importance, there is little information on how this monoculture impacts them. We compared water-quality properties from streams in oil palm plantations (P), paddock and milpa systems (M), and primary forests (F) in the EL. During 2015-2016, 13 rivers were sampled (5 times) for water temperature, pH, dissolved oxygen (DO), conductivity, hardness, chemical and biochemical oxygen demand (COD and BOD), and concentration of silica, nitrates, phosphates, and ammonia. Several parameters showed significant differences. P were 2.7 ºC and 1.8 ºC warmer than M and F and carried 1.4 mg/L more nitrates than F. F carried 10.8 mg/L and 11.8 mg/L more silica than M and P. M showed intermediate temperatures and silica concentrations, as well as 14.8 µS/cm and 8.9 µS/cm lower conductivities than P and F, respectively. Additionally, COD in M was 9.9 mg/L and 4.6 mg/L lower than P and F, respectively. We believe higher temperatures and lower silica in P are due to the loss of riparian forest and their role in buffering temperatures and recycling silicon. In addition, the existence of secondary forest (guamil) in M might explain the intermediate temperatures and silica concentrations. Our results highlight the contributions of forests to waterways and suggest potential water-quality depletion from the oil palm expansion in the EL.

La red hídrica en la Ecorregión Lachuá (EL), Alta Verapaz, Guatemala, alberga una alta biodiversidad y abastece de agua a 44 comunidades mayas. Sin embargo, recientemente se ha visto amenazada por actividades industriales escasamente monitoreadas, incluido el creciente monocultivo de palma africana (Elaeis guineensis Jacq) del cual se desconocen sus impactos en la EL. Este estudio explora la calidad del agua de arroyos en plantaciones de palma africana (P), bosques primarios (B), y sistemas de potrero y milpa (M) en Lachuá. Durante 2015-2016, se tomaron muestras de 13 ríos (5 veces) para medir la temperatura del agua, pH, oxígeno disuelto (OD), conductividad, dureza, demanda química y bioquímica de oxígeno (DQO y DBO) y la concentración de sílice, nitratos, fosfatos, y amoníaco. Varios parámetros mostraron diferencias significativas. P fue 2.7 ºC y 1.8 ºC más calientes que M y F y portó 1.4 mg/L más nitrato que F. F portó 10.8 mg/L y 11.8 mg/L más sílice que M y P. M mostró temperaturas y concentraciones de sílice intermedias y conductividades 14.8 µS/cm y 8.9 µS/cm menores que P y F. La DQO en M fue 9.9 mg/L y 4.6 mg/L menor que P y F. El aumento de temperatura y la disminución de sílice en P podría deberse a la pérdida de bosques ribereños los cuales amortiguan la tempe-ratura y reciclan el silicio. La presencia de bosque secundarios (guamil) en M podría explicar las temperaturas y las concentraciones de sílice intermedias resaltando la importancia de los bosques en la red hídrica. Se predice un posible deterioro en el agua resultado de la expansión de palma africana en la EL.

Effect of miR-204 targeted regulation of DVL3 gene in silica-induced mouse lung epithelial cells / 中华劳动卫生职业病杂志

Objective: To construct a recombinant lentiviral vector for mouse miR-204 overexpression, and to verify the targeted regulation of miR-204 and DVL3 in silica (SiO(2)) -induced mouse lung epithelial cells (MLE-12 cells) . Methods: In October 2019, the pre-miR-204 gene was amplified from the mouse genome by the polymerase chain reaction (PCR) method. After sequencing, the amplified product was cloned into the pLenti-CMV-EGFP lentiviral vector. The positive clones were identified by PCR screening and sequencing. The miR-204 overexpressed lentiviral vector was transfected into 293T cells, and lentiviral packaging and titer determination were performed. The experiment was divided into SiO(2) control group, virus control group, and miR-204 virus group, and the expressions of miR-204 and DVL3 gene were detected by real-time PCR. Results: The miR-204 lentiviral expression vector Lv-miR-204-5p was constructed and identified correctly by PCR and sequencing, and a virus dilution with a titer of 9.57×10(8) IU/ml was obtained. The results of real-time PCR showed that the expression of miR-204 in MLE-12 cells of the miR-204 virus group was higher than that of SiO(2) control group and virus control group, and the expression of DVL3 gene was lower than that of SiO(2) control group and virus control group, the differences were statistically significant (P<0.05) . Conclusion: Overexpression of miR-204 by lentiviral vector may inhibit the expression of DVL3 gene in silica-induced mouse lung epithelial cells.

Regulatory effect of Ac-SDKP on phosphorylated heat shock protein 27/SNAI1 pathway in silicotic rats / 中华劳动卫生职业病杂志

Objective: To study the effect of anti-fibrotic tetrapeptide N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) on phosphorylated heat shock protein 27 (P-HSP27) and zinc finger family transcriptional repressor 1 (SNAI1) expression to explore the anti-silicosis fibrosis effect of Ac-SDKP. Methods: In December 2014, the rat silicosis animal model was prepared by one-time bronchial infusion of silicon dioxide (SiO(2)) dust. 80 SPF healthy adult Wistar rats were selected, and the rats were divided into 8 groups according to the random number table method, 10 in each group. Model control group for 4 weeks (feeding for 4 weeks) , model control group for 8 weeks (feeding for 8 weeks) : bronchial perfusion with normal saline 1.0 ml per animal. Silicosis model group for 4 weeks (feeding for 4 weeks) and silicosis model group for 8 weeks (feeding for 8 weeks) : bronchial perfusion of 50 mg/ml SiO(2) suspension 1.0 ml per animal. Ac-SDKP administration group for 4 weeks (feeding for 4 weeks) , Ac-SDKP administration group for 8 weeks (feeding for 8 weeks) : Ac-SDKP 800 μg·kg(-1)·d(-1) was administered by intraperitoneal pump. Ac-SDKP preventive treatment group: 48 h after Ac-SDKP 800 μg·kg(-1)·d(-1) administration, bronchial perfusion of SiO(2) suspension 1.0 ml per animal, raised for 8 weeks. Ac-SDKP anti-fibrosis treatment group: after bronchial perfusion of 1.0 ml of SiO(2) suspension for 4 weeks, Ac-SDKP 800 μg·kg(-1)·d(-1) was administered for 4 weeks. Western blotting was used to detect the expression of P-HSP27, SNAI1, α-smooth muscle actin (α-SMA) , and collage typeⅠ and Ⅲ in each group. The expression of P-HSP27 and SNAI1 was detected by immunohistochemistry, and the co-localized expression of P-HSP27 and α-SMA was detected by laser confocal microscopy. Results: Compared with the model control group, the expressions of P-HSP27, SNAI1, α-SMA, and collage typeⅠ and Ⅲ in the silicosis fibrosis area of the rats in the silicosis model group were enhanced, and the differences were statistically significant (P<0.05) . After Ac-SDKP intervention, compared with silicosis model group for 8 weeks, the expressions of P-HSP27, SNAI1 α-SMA, and collage typeⅠ and Ⅲ in the Ac-SDKP preventive and anti-fibrosis treatment groups were significantly decreased, and the differences were statistically significant (P<0.05) . However, the expressions of P-HSP27 SNAI1, and collage typeⅠ and Ⅲ between the Ac-SDKP administration group and the model control group did not change significantly, and the differences were not statistically significant (P>0.05) . Laser confocal results showed that the positive cells expressing P-HSP27 and α-SMA in the lung tissue of the silicosis model group were more than those in the model control group. Compared with the silicosis model group, the Ac-SDKP prevention and anti-fibrosis treatment groups expressing the positive cells of P-HSP27 and α-SMA decreased. Compared with the model control group for 8 weeks, there were some double-positive cells expressing P-HSP27 and α-SMA in the nodules of the silicosis model group for 8 weeks. Conclusion: Ac-SDKP may play an anti-silicic fibrosis effect by regulating the P-HSP27/SNAI1 pathway.

Interventional effect of asiaticosdide on rats exposed to silica dust / 中华劳动卫生职业病杂志

Objective: To investigate the effect of asiaticoside for fibrosis in lung tissues of rats exposed to silica and to explore its possible mechanism. Methods: 144 SD male rats were randomly divided into control group, model group, positive drug control group, asiaticoside high-dose group, medium-dose group and low-dose group, each group included 24 rats. Rats in the control group were perfused with 1.0 ml of normal saline, and the other groups were given 1.0 ml 50 mg/ml SiO(2) suspension. Gavage of herbal was given from the next day after model establishment, once a day. Rats in the positive drug control group were administration with 30 mg/kg tetrandrine and rats in the low-dose group, medium-dose group and high-dose group were given 20 mg/kg, 40 mg/kg and 60 mg/kg asiaticoside for fibrosis respectively. Rats in the control group and the model group were given 0.9% normal saline. The rats were sacrificed in on the 14th, 28th and 56th day after intragastric administration and collect the lung tissues to detect the content of hydroxyproline, TGF-β(1) and IL-18, observe the pathological changes of the lung tissues by HE and Masson staining and determine the expressions of Col-I, a-SMA, TGF-β in lung tissues by Western Blot. Results: On the 14th day, 28th day and 56th day after model establishment, the lung tissues of rats in the model group showed obvious inflammatory response and accumulation of collagen fibers, and the degree of inflammation and fibrosis increased with time. The intervention of asiaticoside could effectively inhibit the pathological changes of lung tissues. The contents of hydroxyproline, IL-18 and TGF-β1 in lung tissues of model group were higher than those in the control group (P<0.05) , while the level of hydroxyproline, IL-18 and TGF-β1 in asiaticoside groups were significantly decreased, and the difference was statistically signicant (P<0.05) . Compared with the control group, the expression levels of Col-I, TGF-β1and α-SMA in lung tissue of model group were increased (P<0.05) , while the expression level of Col-I, TGF-β1 and α-SMA were decreased after the intervention of asiaticoside, and the difference was statistically signicant (P<0.05) . Conclusion: Asiaticoside can inhibit the increase of Col-I, TGF-β1 and α-SMA content in the SiO(2)-induced lung tissues of rats, reduce the release of TGF-β1 and IL-18 inflammatory factors in lung tissue, and then inhibit the synthesis and deposition of extracellular matrix in rat lung tissue, and improve silicosis fibrosis.

Change of gene expression profiles in human cardiomyocytes and macrophages infected with SARS / 中南大学学报(医学版)

OBJECTIVES@#Coronavirus disease 2019 (COVID-19) is an acute respiratory infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2 can damage the myocardium directly, or activate the immune system, trigger a cytokine storm, and cause inflammatory cells to infiltrate the myocardial tissue and damage the myocardium. This study is based on the sequencing data to analyze the changes in gene expression of cardiomyocytes and macrophages after SARS-CoV-2 infection, and explore the potential effects of SARS-CoV-2 on the heart and immune system.@*METHODS@#The public data set GSE151879 was retrieved. The online software Network Analyst was used to preprocess the data, and the differentially expressed genes (DEGs) [log@*RESULTS@#After data standardization, the data quality was excellent and it can ensure reliable results. Myocardial cell infection with SARS-CoV-2 and gene expression spectrum were changed significantly, including a total of 484 DEGs in adult cardiomyoblasts, a total of 667 DEGs in macrophages, and a total of 1 483 DEGs in human embryo source of cardiomyopathy. The Stum, mechanosensory transduction mediator homolog (STUM), dehydrogenase/reductase 9 (DHRS9), calcium/calmodulin dependent protein kinase II beta (CAMK2B), claudin 1(CLDN1), C-C motif chemokine ligand 2 (CCL2), TNFAIP3 interacting protein 3 (TNIP3), G protein-coupled receptor 84 (GPR84), and C-X-C motif chemokine ligand 1 (CXCL1) were identical in expression patterns in 3 types of cells. The protein-protein interaction suggested that CAMK2B proteins may play a key role in the antiviral process in 3 types of cells; and silicon dioxide (SiO@*CONCLUSIONS@#CAMK2B, CLDN1, CCL2, and DHRS9 genes play important roles in the immune response of cardiomyocytes against SARS-CoV-2. SiO

Effects of bioactive glass on proliferation, differentiation and angiogenesis of human umbilical vein endothelial cells / 北京大学学报(医学版)

OBJECTIVE@#To investigate the effects of phytic acid derived bioactive P2O5-SiO2-CaO gel-glasses (PSC) on the proliferation, differentiation and angiogenesis of human umbilical vein endothelial cells (HUVECs) in vitro.@*METHODS@#HUVECs were cultured in PSC extracts, which were prepared with endothelial cell medium (ECM) at a gradient concentration of 0.01, 0.1, 1 and 2 g/L. Cells cultured in ECM were used as the control. The effect of PSC on HUVECs proliferation was assessed on the 1st, 3rd, 5th, 7th and 10th days with (4, 5-dimethylthiazol-2-yl) 2, 5-diphenyltetrazolium bromide assay (MTT), and the optimum PSC concentration for HUVECs proliferation was used in the following experiments. The subsequent experiments were divided into two groups. The experimental group used PSC extracts to culture HUVECs (PSC group) and the control group used ECM to culture HUVECs (ECM group). Gene expression of angiogenic factors, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), was detected on the 2nd, 4th and 7th days by real-time reverse transcription-polymerase chain reaction (real-time RT-PCR). The morphology and number of tubules formation were observed at the 4th and 10th hours. Image J software was used for counting and quantitative analysis.@*RESULTS@#The results of MTT assay showed that 0.1 g/L PSC group had the most significant effect on promoting HUVECs proliferation. The optical density values of 0.1 g/L PSC group on the 5th and 7th days were significantly higher than those of the other PSC groups and the control group (P < 0.05). The result of real-time RT-PCR showed that 0.1 g/L PSC extract up-regulated the mRNA expression of VEGF and bFGF significantly (P < 0.05). On the 4th day, the gene expressions of VEGF and bFGF in PSC group were 1.59 and 1.45 times higher than those in ECM group respectively, and on the 7th day, the gene levels of VEGF and bFGF in PSC group were 1.98 and 1.37 times higher than those in ECM group respectively. The tubule formation assay showed that the maturity and density of the tubules in 0.1 g/L PSC group was much better than that in the ECM group at the 10th hour. The quantitative analysis by Image J indicated that the tubules number in PSC group (29.63±2.29) was higher than in the ECM group (20.13±2.36), with statistical significance (P < 0.05).@*CONCLUSION@#PSC showed significant promoting effects on HUVECs' proliferation, differentiation and angiogenesis in vitro.

Comparative effect of calcium mesoporous silica versus calcium and/or fluoride products against dental erosion

Abstract The aim of this study was to compare the effects of a single application of a new calcium mesoporous silica nanoparticle (Ca2+-MSN) versus other calcium and/or fluoride products against dental erosion. Enamel blocks were half-covered and assigned to six groups (n = 10): Ca2+-MSNs; casein phosphopeptide-amorphous calcium phosphate mousse (CPP-ACP); CPP-ACP/F− (900 ppm F−); titanium tetrafluoride (TiF4 1%); sodium fluoride (NaF 1.36%); and Milli-Q® water (negative control). A single application for each product was completed on the exposed areas of the blocks and were submitted to an erosive challenge. Differences in volumetric roughness (Sa), and tooth structure loss (TSL) by use of three-dimensional noncontact optical profilometry were evaluate. Scanning electron microscopy (SEM) was performed. Analysis of variance and Tukey's test for Sa and the Kruskal-Wallis and Mann-Whitney U tests (p< 0.05) for TSL, respectively. Results: When evaluating Sa, all products presented differences in roughness when compared with the control group (p< 0.05) but not with each other (p > 0.05). However, when analyzing the TSL, it was observed that Ca2+-MSNs, TiF4, and NaF were more effective in preventing dental erosion versus CPP-ACP, CPP-ACP/F−, and Milli-Q® water (p< 0.05). In the SEM images, the negative control presented the worst loss of dental structure, with more porous enamel. Ca2+-MSNs were as effective as TiF4 and NaF to reduce the tooth structure loss.

Resumo O objetivo deste estudo foi comparar os efeitos de uma única aplicação de uma nova nanopartícula de sílica mesoporosa de cálcio (Ca2+ -MSN) versus outros produtos à base de cálcio e / ou fluoreto contra a erosão dentária. Blocos de esmalte foram parcialmente cobertos e distribuídos em seis grupos (n = 10): Ca2+ -MSNs; fosfopeptídeos de caseína/fosfato de cálcio amorfo (CPP-ACP); CPP-ACP / F- (900 ppm F-); tetrafluoreto de titânio (TiF4 1%); fluoreto de sódio (NaF 1,36%); e água Milli-Q® (controle negativo). Uma única aplicação para cada produto foi realizada nas áreas expostas dos blocos e submetida a desafio erosivo. Diferenças na rugosidade volumétrica (Sa) e na perda de estrutura dentária (TSL) por meio de perfilometria tridimensional de não contato foram avaliadas. Microscopia eletrônica de varredura (MEV) foi realizada. Foram realizadas análise de variância e teste de Tukey para os testes Sa e Kruskal-Wallis e Mann-Whitney (p<0,05) para TSL, respectivamente. Na avaliação de Sa, todos os produtos apresentaram diferenças de rugosidade quando comparados ao grupo controle (p<0,05), mas não entre si (p> 0,05). No entanto, ao analisar o TSL, observou-se que Ca2+ -MSNs, TiF4 e NaF foram mais eficazes na prevenção da erosão dental versus CPP-ACP, CPP-ACP / F- e Milli-Q® (p<0,05). Nas imagens de MEV, o controle negativo apresentou a pior perda de estrutura dentária, com o esmalte mais poroso. A Ca2+ -MSNs foi tão eficaz quanto o TiF4 e o NaF para reduzir a perda da estrutura dentária.

Urea incorporated into ordered mesoporous silica for potential cosmetic application

Urea's thermal instability and burning on sensitive skin can cause problems for cosmetic formulations. To overcome these drawbacks, urea was incorporated into ordered mesoporous silica (SBA-15). SBA-15 was synthesized using tetraethyl orthosilicate and Pluronic® P123 in an acid medium. Urea (20 wt.%) was incorporated into calcined SBA-15 by the incipient wetness impregnation method. Several techniques were used to characterize the samples. Skin hydration and transepidermal water loss were measured using Corneometer® CM 825 PC and Tewameter® 300 TM. Results showed that the structural properties of SBA-15Urea were similar to pure SBA-15, indicating that SBA-15 remained structured even after urea incorporation. Nitrogen physisorption data showed the volume and surface area of the pores in SBA-15Urea were much lower than those in SBA-15, demonstrating that urea was deposited inside the mesopores. In vivo moisturization studies revealed that SBA-15Urea was not able to reduce transepidermal water loss compared to the other products and control, while forming a non-occlusive surface film on the skin. We conclude that incorporation of urea in the pores of the inorganic SBA-15 matrix is a promising approach to enhancing its stability and providing a prolonged moisturizing effect.

The use of a new calcium mesoporous silica nanoparticle versus calcium and/or fluoride products in reducing the progression of dental erosion

Abstract Objective There is increasingly common the consumption more times a day of foods and acidic drinks in the diet of the population. The present study aimed to evaluate and compare the effects of a calcium mesoporous silica nanoparticle single application of other calcium and/or fluoride products in reducing the progression of dental erosion. Methodology Half of the eroded area was covered of 60 blocks of enamel, after which the block was submitted to the following treatments: (Ca2+-MSN), casein phosphopeptide-amorphous calcium phosphate (CPP-ACP); CPP-ACP/F-(900 ppm F−); titanium tetrafluoride (TiF4 1%) (positive control); sodium fluoride (NaF 1.36%) (positive control); and Milli-Q® water (negative control) before being submitted to a second erosive challenge. A surface analysis was performed via a three-dimensional (3D) noncontact optical profilometry to assess the volumetric roughness (Sa) and tooth structure loss (TSL) and and through scanning electron microscopy (MEV). An analysis of variance (ANOVA) and Tukey's test were performed. Results Regarding Sa, all experimental groups exhibited less roughness than the control (p<0.05). The TSL analysis revealed that the Ca2+-MSN and NaF groups were similar (p>0.05) and more effective in minimizing tooth loss compared with the other groups (p<0.05). Conclusions The Ca2+-MSN and NaF treatments were superior compared with the others and the negative control.

Effect of Silicon dioxide coating of acrylic resin surfaces on Candida albicans adhesion

Abstract Acrylic resin has been used in the manufacture of prostheses, however, in the oral cavity, this material starts to retain microorganisms capable of causing gingival inflammation due its porosities. The aim of this study was to evaluate the influence of the use of silicon dioxide as a coating layer applied onto acrylic resin, on the adhesion of Candida albicans (Ca). After the incubation period in Sabouraud Dextrose Broth, a total of 1 ml of the Ca suspension was added to plate wells, each well containing a specimen of acrylic resin. The adhesion ability of Ca on acrylic resin was determined by counting colonies. Three groups (n = 6) of acrylic resin were assessed: with polishing (RP); without polishing (RW); with polishing and coating layer of silicon dioxide (RPC). Ca deposited on the surface of the acrylic resin was also observed using Scanning Electron Microscopy (SEM). Statistical assessment by Kruskal-Wallis and Student-Newman-Keuls Method were done (α = 2%). There was significant difference among the groups. The RPC group showed the lowest growth, with an average of 5.59 Log CFU/cm 2 ; there was a statistically significant difference in relation to group RW, which presented a growth of 6.07 Log CFU/cm 2 and to group RP with 5.91 Log CFU/cm 2 (p < 000.1). SEM images demonstrated that in the RP and RPC group, the surface of the resin had greater regularity, and smaller number of microorganisms. The application of silicon dioxide coating on acrylic resin appears to be a promising alternative, and its use can help in reducing the adhesion of Ca in prostheses.

Mesoporous silica nanoparticles for bone tissue engineering / 中国骨伤

As a new potential bone graft material, tissue engineered bone effectively compensates for the defects of today's bone repair materials. Meanwhile, mesoporous silica nanomaterials(MSNs) have been widely recognized due to their large specific surface area, good biocompatibility, and capability of further processing and modification. They have promising application prospects in bone tissue engineering. For the basic scientific research results that have been carried out in the early stage, the basic characteristics of mesoporous silica nano biomaterials and their application advantages, research status and development prospects in bone tissue engineering are reviewed. As for the research status, there are two aspects--as a carrier or as a component of engineering scaffolds. For the first aspect, different kinds of loaded drugs and different loading methods are reviewed. For the second, microstructure and mechanical properties of various complex scaffolds containing MSNs and the molecular and cellular behavior of seeded cells on these scaffolds are reviewed. The research of MSNs in bone cements and metal ions doped MSNs in bone tissue engineering are also included. The future development of MSNs in bone tissue engineering is also discussed.

Hollow silica reinforced magnesium nanocomposites with enhanced mechanical and biological properties with computational modeling analysis for mandibular reconstruction / 国际口腔科学杂志·英文版

The present study investigates Mg-SiO

Effect of surface treatments and universal adhesive application on the microshear bond strength of CAD/CAM materials

PURPOSE: The aim of this study was to evaluate the microshear bond strength (µSBS) of four computer-aided design/computer-aided manufacturing (CAD/CAM) blocks repaired with composite resin using three different surface treatment protocols.MATERIALS AND METHODS: Four different CAD/CAM blocks were used in this study: (1) flexible hybrid ceramic (FHC), (2) resin nanoceramic (RNC), (c) polymer infiltrated ceramic network (PICN) and (4) feldspar ceramic (FC). All groups were further divided into four subgroups according to surface treatment: control, hydrofluoric acid etching (HF), air-borne particle abrasion with aluminum oxide (AlO), and tribochemical silica coating (TSC). After surface treatments, silane was applied to half of the specimens. Then, a silane-containing universal adhesive was applied, and specimens were repaired with a composite, Next, μSBS test was performed. Additional specimens were examined with a contact profilometer and scanning electron microscopy. The data were analyzed with ANOVA and Tukey tests.RESULTS: The findings revealed that silane application yielded higher µSBS values (P<.05). All surface treatments were showed a significant increase in µSBS values compared to the control (P<.05). For FHC and RNC, the most influential treatments were AlO and TSC (P<.05).CONCLUSION: Surface treatment is mandatory when the silane is not preferred, but the best bond strength values were obtained with the combination of surface treatment and silane application. HF provides improved bond strength when the ceramic content of material increases, whereas AlO and TSC gives improved bond strength when the composite content of material increases.

Effect of flowable composite or glass ionomer liners on shrinkage stress of a composite resin / Efecto de recubrimientos con resinas de baja viscosidad o ionómero vitreo sobre la tensión por contracción de una resina compuesta

ABSTRACT The aim of this study was to evaluate the effect of flowable composite or glass ionomer liners on the shrinkage stress of a restorative composite resin. Fifteen previously sandblasted metal boxes were attached to a universal mechanical testing machine (INSTRON 1011, Instron Corporation). Five of these boxes were filled with Filtek Z350 XT (FXT) Universal Restorative A2 (3M ESPE) (Group 1 or Control). Two further groups of 5 boxes were prepared by interposing a layer of Vitrebond Light Cure Glass Ionomer 3M ESPE (VGI) (Group 2 or G.I.) or Filtek Z350 XT Flowable Restorative A2 3M ESPE (FFR) (Group 3 or Flowable) between the box and the composite resin, completing with the same volume of composite as in Group 1. Upon activating lightcuring, the filled boxes mounted on the testing machine were videoed for 60 seconds (40 s photoactivation and 20 s postcuring), timed with a digital chronometer. Force values were recorded in newtons and converted into stress according to contact surface. Stress values were recorded every 10 s. Results were analyzed using repeated measures ANOVA. Mean and standard deviation in kPa (stress) recorded for each group were: Control group: 126.2 (30.8); G.I.: 48.4 (18); Flowable: 27.9 (19.5). Statistical analysis showed significant differences between the control group and the rest (p<0.01), with no significant difference between groups with glass ionomer liners and flowable resin liners (G.I. and Flowable). Under the experimental conditions of this study, it can be concluded that polymerization shrinkage stress can be reduced by the presence of a liner between the preparation and the restorative material.

RESUMEN El objetivo de este trabajo fue evaluar el efecto de la colocación de una capa de Composite flow o Ionómero vítreo sobre la tensión de contracción de un composite para restauración. Se utilizaron 15 cajas metálicas previamente arenadas y conectadas a la máquina universal para ensayos mecánicos (INSTRON 1011, Instron Corporation). Cinco de estas cajas (G1) se rellenaron con Filtek Z350 XT (FXT) Universal Restorative A2 3M ESPE. Al iniciar la activación de la unidad de curado se comenzaba a registrar con una cámara de video y un cronómetro digital desde el comienzo de la activación de la lámpara hasta 60 s después, registrando los valores post curado durante 20 s. Los valores de fuerza generados por la polimerización fueron registrados en newton de cada 10 s para los 15 ensayos. Los valores fueron convertidos en tensión de contracción según la superficie de contacto. Se realizaron además dos grupos de cajas (5 en cada una) en los cuales se colocaron una capa inicial de Vitrebond Light Cure Glass Ionomer 3M ESPE (VGI) (G2 o IV) y Filtek Z350 XT Flowable Restorative A2 3M ESPE (FFR) (G3 o Flow) y se completó con el mismo volumen de composite de las del GI. Los resultados obtenidos fueron analizados por medio de ANOVA para mediciones repetidas. La media y la desviación estándar en kPa (tensión o estrés de contracción) registrado para cada grupo fueron: Grupo control: 126.2 (30.8); IV: 48.4(18); Flow: 27.9(19.5). El análisis estadístico mostró diferencias estadística mente significativas entre el grupo control y el resto (p=0.00), pero no hubo diferencias significativas entre la presencia de Ionómero vítreo o Composite Flow (IV y Flow). En las condiciones experimentales de este trabajo puede concluirse que la tensión de contracción generada durante la polimerización puede ser disminuida por la presencia de algún material interpuesto entre la preparación y el composite restaurador.

Tissue response after subcutaneous implantation of different glass ionomer-based cements

Abstract The aim of this study was to evaluate the subcutaneous connective tissue response of isogenic mice after implantation of different glass ionomer-based cements (EQUIA® Forte Fil, EQUIA® Fil and Ketac™ Universal Aplicap™). Eighty-seven isogenic BALB/c mice were allocated in 12 groups, 9 were considered as experimental groups (Ketac, E. Fil and E. Forte at 7, 21 and 63 days) and 3 controls (empty polyethylene tubes at 7, 21 and 63 days). After the experimental periods, the subcutaneous connective tissue surrounding the implanted material was removed and subjected to histotechnical processing and staining with hematoxylin and eosin. A histopathological description of the tissue reaction surrounding each material and a semi-quantitative analysis of collagen fiber formation and inflammatory infiltrate were performed. Additionally, the thickness of the granulomatous tissue in contact with each material was measured. Data were analyzed statistically (α=0.05) by the Kruskal-Wallis test, followed by Dunn post-test. Initially, the collagen fiber formation was not different among all the tested materials (p>0.05) but was different at 21 days with the control group presenting the most advanced stage of collagen fiber formation. At 63 days, EQUIA® Forte Fil group showed the most advanced stage of collagen fiber formation, compared to EQUIA® Fil group (p<0.05). The inflammatory infiltrate was not different among the tested materials in any experimental period (p>0.05). The thickness of the granulomatous tissue was greater in the E. Forte group, compared to control in all periods. All glass ionomer-based cements showed tissue compatibility, according to the evaluated parameters.

Resumo O objetivo deste estudo foi avaliar a resposta subcutânea do tecido conjuntivo de camundongos isogênicos após o implante de diferentes cimentos à base de ionômero de vidro (EQUIA® Forte Fil, EQUIA® Fil e Ketac ™ Universal Aplicap ™). Oitenta e sete camundongos isogênicos BALB/c foram alocados em 12 grupos, 9 como grupos experimentais (Ketac, E. Fil e E. Forte aos 7, 21 e 63 dias) e 3 controles (tubos de polietileno vazios aos 7, 21 e 63 dias). Após os períodos experimentais, o tecido conjuntivo subcutâneo ao redor do material implantado foi removido e submetido ao processamento histotécnico e coloração com hematoxilina e eosina. Uma descrição histopatológica da reação tecidual envolvendo cada material e uma análise semi-quantitativa da fibrose e infiltrado inflamatório foram realizadas. Além disso, foi realizada a mensuração da espessura do tecido granulomatoso em contato com cada material. Os dados foram analisados estatisticamente (α=0,05) pelo teste de Kruskal-Wallis, seguido do pós-teste de Dunn. Inicialmente, a fibrose não foi diferente entre todos os materiais testados (p>0,05), mas foi diferente aos 21 dias, com o grupo controle apresentando o estágio mais avançado de fibrose. Aos 63 dias, o grupo EQUIA® Forte Fil apresentou o estágio mais avançado de fibrose, comparado ao grupo EQUIA® Fil (p<0,05). O infiltrado inflamatório não foi diferente entre os materiais testados em nenhum período experimental (p>0,05). A espessura do tecido granulomatoso foi maior no grupo E. Forte, comparado ao controle em todos os períodos. Todos os cimentos à base de ionômero de vidro apresentaram compatibilidade tecidual, de acordo com os parâmetros avaliados.

Color alterations of a PMMA resin for fixed interim prostheses reinforced with silica nanoparticles

PURPOSE: The aim of the present study was to evaluate the color changes of an autopolymerizing PMMA resin used for interim fixed restorations, reinforced with SiO2 nanoparticles. MATERIALS AND METHODS: Silica nanoparticles were blended with the PMMA resin powder through high-energy ball milling. Four shades of PMMA resin were used (A3, B3, C3, D3) and total color differences were calculated through the equations ΔEab= [(ΔL*)2 + (Δa*)2 + (Δb*)2]½ and Δ E 00 = [ Δ L ′ K L S L 2 + Δ C ′ K C S C 2 + Δ H ′ K H S H 2 + R T Δ C ′ K C S C Δ H ′ K H S H ] 1 / 2 . Statistically significant differences between ΔEab and the clinically acceptable values of 3.3 and 2.7 and those between ΔE00 and the clinically acceptable value of 1.8 were evaluated with one sample t-test (P<.05). Differences among the different shades were assessed through One-Way ANOVA and Bonferroni multiple comparison tests. RESULTS: Significantly lower values were detected for all groups concerning ΔEab compared to the intraorally clinical acceptable values of 3.3 and 2.7. Significantly lower mean values were detected for groups B3, C3, and D3, concerning ΔE00 compared to the intraorally clinical acceptant value of 1.8. Color pigments in red-brown (A3) and red-grey (D3) shades affect the total color change to a greater extent after the reinforcement with SiO2 nanoparticles compared to the red-yellow (B3) shade. CONCLUSION: Within the limitations of this in vitro study, it can be suggested that reinforcing PMMA with SiO2 nanoparticles at 0.25 wt% slightly affects the optical properties of the PMMA resin without being clinically perceivable.

Effect of surface treatments on the bond strength of indirect resin composite to resin matrix ceramics

PURPOSE: The purpose of this study was to evaluate the shear bond strength (SBS) of an indirect resin composite (IRC) to the various resin matrix ceramic (RMC) blocks using different surface treatments. MATERIALS AND METHODS: Ninety-nine cubic RMC specimens consisting of a resin nanoceramic (RNC), a polymer-infiltrated hybrid ceramic (PIHC), and a flexible hybrid ceramic (FHC) were divided randomly into three surface treatment subgroups (n = 11). In the experimental groups, untreated (Cnt), tribochemical silica coating (Tbc), and Neodymium-Doped Yttrium Aluminum Garnet (Nd:YAG) laser irradiation (Lsr) with 3 W (150 mJ/pulse, 20 Hz for 20 sec.) were used as surface treatments. An indirect composite resin (IRC) was layered with a disc-shape mold (2 × 3 mm) onto the treated-ceramic surfaces and the specimens submitted to thermal cycling (6000 cycles, 5 – 55℃). The SBS test of specimens was performed using a universal testing machine and the specimens were examined with a scanning electron microscope to determine the failure mode. Data were statistically analyzed with two-way analysis of variance (ANOVA) and Tukey HSD test (α=.05). RESULTS: According to the two-way ANOVA, only the surface treatment parameter was statistically significant (P<.05) on the SBS of IRC to RMC. The SBS values of Lsr-applied RMC groups were significantly higher than Cnt groups for each RMC material, (P<.05). Significant differences were also determined between Tbc surface treatment applied and untreated (Cnt) PIHC materials (P=.039). CONCLUSION: For promoting a reliable bond strength during characterization of RMC with IRC, Nd:YAG laser or Tbc surface treatment technique should be used, putting in consideration the microstructure and composition of RMC materials and appropriate parameters for each material.

In vitro wear behavior between enamel cusp and three aesthetic restorative materials: Zirconia, porcelain, and composite resin

PURPOSE: The aim of this study was to identify the effects of three aesthetic restorative materials on the wear between tooth and restoration by a pin-on-disk manner. MATERIALS AND METHODS: Six aesthetic restorative materials were used to prepare disk specimens for wear test, which were Lava Zirconia as zirconia group, Vintage MP and Cerabien ZR as veneering porcelain group, Gradia Direct microhybrid composite containing prepolymerized fillers, Filtek Z250 microhybrid composite containing zirconia glass and colloidal silica particles, and Filtek Z350 nanocomposite as composite resin group. Vertical loss of the worn cusp, change of the surface roughness of the restoration materials, and the surface topography were investigated after wear test under 9.8-N contact load. RESULTS: The porcelain groups (Vintage MP and Cerabien ZR) caused the largest vertical loss of teeth when compared with those of the composite resin and zirconia groups, and Filtek Z250 microhybrid composite results in the second-largest vertical loss of teeth. The surface of Filtek Z350 nanocomposite was deeply worn out, but visible wear on the surface of the zirconia and Gradia Direct microhybrid composite was not observed. When the zirconia surface was roughened by sand-blasting, vertical loss of teeth considerably increased when compared with that in the case of fine polished zirconia. CONCLUSION: It was identified that microhybrid composite resin containing a prepolymerized filler and zirconia with reduced surface roughness by polishing were the most desirable restorative materials among the tested materials to prevent the two-body wear between aesthetic restorative material and tooth.

Difference of silicon dioxide-stimulated macrophage-derived exosomal miRNA expression profile / 中南大学学报(医学版)

To analyze the differential expression of RAW264.7 macrophage-derived exosomes miRNA stimulated by free silicon dioxide (SiO2).
 Methods: RAW264.7 was stimulated with SiO2 (200 mg/L) for 48 h (exo_48 h group), and the supernatant was collected. The exosomes in the supernatant were extracted by ultracentrifugation. Transmission microscopy, nanoparticle tracking analysis (NTA) and Western blotting were used to identify exosomes. High-throughput sequencing was performed to compare the differential expression of exosome miRNAs between the exo_control group (RAW264.7 cultured for 48 h without SiO2) and the exo_48 h group; miRanda, TargetScan and starBase were used to predict target genes of differential miRNAs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed on target genes to further analyze the biological functions of genes.
 Results: The transmission microscopy showed that the exosomes were lipid membrane coated vesicles, which were heterogeneously distributed, with a diameter ranging from 30 to 100 nm, and the shape was round or elliptical. The volume kurtosis was concentrated between 40 and 100 nm and the exosome marker protein TSG101 was positive. High-throughput sequencing screened 148 differentially expressed exosomal miRNAs. MiR-219c-3p, let-7d-3p, let-7a-1-3p, miR-328-3p, miR-365-3p, and miR-7219-3p were significantly up-regulated, and miR-378d and miR-5106 were significantly down-regulated compared with the control group. Target genes were mainly enriched in mTOR signaling pathway, Wnt signaling pathway, TGF-β signaling pathway, and so on.
 Conclusion: The exosomes secreted by SiO2-induced macrophages contain abundant miRNAs, and their expressions are significantly different. These differential miRNAs may be involved in the activation of lung fibroblasts and epithelial-mesenchymal transition.