Early hardness of self-adhesive resin cements cured under indirect resin composite restorations.

PubMed

Giráldez, Isabel; Ceballos, Laura; Garrido, Miguel A; Rodríguez, Jesús

2011-04-01

To determine the influence of curing mode on the surface hardness of seven resin cements used to lute indirect composite restorations. Seven commercial dual-curing resin cements were tested: two were total-etch (RelyX ARC [3M ESPE, St. Paul, MN, USA] and Variolink II [Ivoclar Vivadent, Schaan, Liechtenstein]); one was self-etch (Multilink Automix [Ivoclar Vivadent]), and four were self-adhesive (RelyX Unicem [3M ESPE], Maxcem Elite [Kerr Corp., Orange, CA, USA], SmartCem2 [Dentsply, Detrey, GmbH, Konstanz, Germany], and G-Cem [GC CORPORATION, Itabashi-Ku, Tokyo, Japan]). Three specimens (0.5 × 6.5mm) of each material were prepared for each of three experimental groups: Group 1 (cements allowed to self cure); Group 2 (cements light-cured for 40 seconds); and Group 3 (cements light-cured for 80 seconds). All specimens were cured through a 4-mm-thick composite cylinder (Filtek Z250-A3). Surface microhardness numbers were determined at 20 min after preparation. Results were analyzed by two-way analysis of variance and Student-Newman-Keuls tests (p<0.05). Superficial hardness was significantly influenced by the resin cement tested (p<0.0001), the curing mode (p<0.0001), and their interaction (p<0.0001). RelyX ARC exhibited the highest mean microhardness values regardless of the curing mode. Light-curing significantly increased the microhardness of all resin cements studied, and these values increased even further with a doubling of irradiation time. Self-adhesive cements exhibited different behavior according to the curing mode. RelyX Unicem was highly sensitive to light irradiation, showing the lowest mean values in the self-curing mode. After light irradiation for 40 or 80 seconds, Maxcem Elite exhibited the lowest mean hardness values of all the resin cements tested. The microhardness of resin cements is highly dependent on the brand. Dual-curing resin cements should always be light irradiated for longer periods than that recommended by manufacturers. Dual-curing resin cements should always be light-cured for longer irradiation times, as light irradiation for 80 seconds yields the highest microhardness values in comparison with self-curing or light irradiation for 40 seconds. However, some self-adhesive resin cements exhibit low microhardness values when used to cement 4-mm-thick indirect composite restorations regardless of the curing mode applied. © 2011, COPYRIGHT THE AUTHORS. JOURNAL COMPILATION © 2011, WILEY PERIODICALS, INC.

Bonding efficacy of new self-etching, self-adhesive dual-curing resin cements to dental enamel.

PubMed

Benetti, Paula; Fernandes, Virgílio Vilas; Torres, Carlos Rocha; Pagani, Clovis

2011-06-01

This study evaluated the efficacy of the union between two new self-etching self-adhesive resin cements and enamel using the microtensile bond strength test. Buccal enamel of 80 bovine teeth was submitted to finishing and polishing with metallographic paper to a refinement of #600, in order to obtain a 5-mm2 flat area. Blocks (2 x 4 x 4 mm) of laboratory composite resin were cemented to enamel according to different protocols: (1) untreated enamel + RelyX Unicem cement (RX group); (2) untreated enamel + Bifix SE cement (BF group); (3) enamel acid etching and application of resin adhesive Single Bond + RelyX Unicem (RXA group); (4) enamel acid etching and application of resin adhesive Solobond M + Bifix SE (BFA group). After 7 days of storage in distillated water at 37°C, the blocks were sectioned for obtaining microbar specimens with an adhesive area of 1 mm2 (n = 120). Specimens were submitted to the microtensile bond strength test at a crosshead speed of 0.5 mm/min. The results (in MPa) were analyzed statistically by ANOVA and Tukey's test. Enamel pre-treatment with phosphoric acid and resin adhesive (27.9 and 30.3 for RXA and BFA groups) significantly improved (p ≤ 0.05) the adhesion of both cements to enamel compared to the union achieved with as-polished enamel (9.9 and 6.0 for RX and BF). Enamel pre-treatment with acid etching and the application of resin adhesive significantly improved the bond efficacy of both luting agents compared to the union achieved with as-polished enamel.

Premolar Axial Wall Height Effect on CAD/CAM Crown Retention

DTIC Science & Technology

2016-05-24

OC axial wall height was required in a study that involved zirconia copings cemented on stainless steel dies. The results of this study reinforced...surface area was determined using a digital measuring microscope (Hirox). Scanned preparations (CEREC) were fitted with e.max CAD crowns and cemented ...Figure 14. RelyX Unicem Cementation

The influence of four dual-cure resin cements and surface treatment selection to bond strength of fiber post

PubMed Central

Liu, Chang; Liu, Hong; Qian, Yue-Tong; Zhu, Song; Zhao, Su-Qian

2014-01-01

In this study, we evaluate the influence of post surface pre-treatments on the bond strength of four different cements to glass fiber posts. Eighty extracted human maxillary central incisors and canines were endodontically treated and standardized post spaces were prepared. Four post pre-treatments were tested: (i) no pre-treatment (NS, control), (ii) sandblasting (SA), (iii) silanization (SI) and (iv) sandblasting followed by silanization (SS). Per pre-treatment, four dual-cure resin cements were used for luting posts: DMG LUXACORE Smartmix Dual, Multilink Automix, RelyX Unicem and Panavia F2.0. All the specimens were subjected to micro push-out test. Two-way analysis of variance and Tukey post hoc tests were performed (α=0.05) to analyze the data. Bond strength was significantly affected by the type of resin cement, and bond strengths of RelyX Unicem and Panavia F2.0 to the fiber posts were significantly higher than the other cement groups. Sandblasting significantly increased the bond strength of DMG group to the fiber posts. PMID:24177170

Effect of indirect composite treatment microtensile bond strength of self-adhesive resin cements

PubMed Central

Escribano, Nuria; Baracco, Bruno; Romero, Martin; Ceballos, Laura

2016-01-01

Background No specific indications about the pre-treatment of indirect composite restorations is provided by the manufacturers of most self-adhesive resin cements. The potential effect of silane treatment to the bond strength of the complete tooth/indirect restoration complex is not available.The aim of this study was to determine the contribution of different surface treatments on microtensile bond strength of composite overlays to dentin using several self-adhesive resin cements and a total-etch one. Material and Methods Composite overlays were fabricated and bonding surfaces were airborne-particle abraded and randomly assigned to two different surface treatments: no treatment or silane application (RelyX Ceramic Primer) followed by an adhesive (Adper Scotchbond 1 XT). Composite overlays were luted to flat dentin surfaces using the following self-adhesive resin cements: RelyX Unicem, G-Cem, Speedcem, Maxcem Elite or Smartcem2, and the total-etch resin cement RelyX ARC. After 24 h, bonded specimens were cut into sticks 1 mm thick and stressed in tension until failure. Two-way ANOVA and SNK tests were applied at α=0.05. Results Bond strength values were significantly influenced by the resin cement used (p<0.001). However, composite surface treatment and the interaction between the resin cement applied and surface treatment did not significantly affect dentin bond strength (p>0.05). All self-adhesive resin cements showed lower bond strength values than the total-etch RelyX ARC. Among self-adhesive resin cements, RelyX Unicem and G-Cem attained statistically higher bond strength values. Smartcem2 and Maxcem Elite exhibited 80-90% of pre-test failures. Conclusions The silane and adhesive application after indirect resin composite sandblasting did not improve the bond strength of dentin-composite overlay complex. Selection of the resin cement seems to be a more relevant factor when bonding indirect composites to dentin than its surface treatment. Key words:Bond strength, self-adhesive cement, silane, dentin, indirect composite. PMID:26855700

Factors affecting the cement-post interface.

PubMed

Zicari, F; De Munck, J; Scotti, R; Naert, I; Van Meerbeek, B

2012-03-01

To evaluate the effect of different factors on the push-out bond strength of glass fiber posts luted in simulated (standard) root canals using different composite cements. Three types of glass-fiber root-canal posts with a different matrix, namely an epoxy resin (RelyX post, 3M ESPE), a proprietary composite resin (FRC-Plus post, Ivoclar-Vivadent), and a methacrylate resin (GC post, GC), and three types of composite cements, namely an etch-and-rinse Bis-GMA-based (Variolink II, Ivoclar-Vivadent), a self-etch 10-MDP-based (Clearfil Esthetic Cement, Kuraray) and a self-adhesive (RelyX Unicem, 3M ESPE) cement, were tested. Posts were either left untreated (control), were treated with silane, or coated with silicated alumina particles (Cojet system, 3M ESPE). Posts were inserted up to 9-mm depth into composite CAD-CAM blocks (Paradigm, 3M ESPE) in order to solely test the strength of the cement-post interface, while excluding interference of the cement-dentin interface. After 1-week storage at 37 °C, three sections (coronal, middle, apical) of 2-mm thickness were subjected to a push-out bond-strength test. All three variables, namely the type of post, the composite cement and the post-surface pre-treatment, were found to significantly affect the push-out bond strength (p<0.001). Regarding the type of post, a significantly lower push-out bond strength was recorded for the FRC-Plus post (Ivoclar-Vivadent); regarding the composite cement, a significantly higher push-out bond strength was recorded for the self-adhesive cement Unicem (3M ESPE); and regarding the post-surface treatment, a significantly higher push-out bond strength was recorded when the post-surface was beforehand subjected to a Cojet (3M ESPE) combined sandblasting/silicatization surface pre-treatment. Many interactions between these three variables were found to be significant as well (p<0.001). Finally, the push-out bond strength was found to significantly reduce with depth from coronal to apical. Laboratory testing revealed that different variables like the type of post, the composite cement and the post-surface pre-treatment may influence the cement-post interface, making clear guidelines for routine clinical practice hard to define. Further long-term durability testing may help to clarify, and should therefore be encouraged. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Nanoleakage for Self-Adhesive Resin Cements used in Bonding CAD/CAD Ceramic Material to Dentin

PubMed Central

El-Badrawy, Wafa; Hafez, Randa Mohamed; El Naga, Abeer Ibrahim Abo; Ahmed, Doaa Ragai

2011-01-01

Objectives: To determine nanoleakage of CAD/CAM ceramic blocks bonded to dentin with self-adhesive resin cement. Methods: Eighteen sound extracted human molars were sterilized and sectioned into 3 mm-thick dentin sections. Trilux Cerec Vitablocks (Vita) were also sectioned into 3 mm sections, surface-treated using 5% hydrofluoric acid-etchant, and then coated with silane primer (Vita). Trilux and dentin sections were cemented together by means of three resin cements: Rely-X Unicem (3M/ESPE), BisCem (Bisco), and Calibra (Dentsply), according to manufacturers’ recommendations. Calibra was used in conjunction with Prime/Bond-NT adhesive (Dentsply), while the other two are self-adhesive. The bonded specimens were stored for 24h in distilled water at 37°C. Specimens were vertically sectioned into 1 mm-thick slabs, yielding up to six per specimen. Two central slabs were randomly chosen from each specimen making up the cement groups (n=12). Each group was subdivided into two subgroups (n=6), a control and a thermocycled subgroup (5–55°C) for 500 cycles. Slabs were coated with nail polish up to 1 mm from the interface, immersed in a 50% silver nitrate solution for 24h, and tested for nanoleakage using Quanta Environmental SEM and EDAX. Data were statistically analyzed using two-way ANOVA and Tukey’s post-hoc tests. Results: Rely-X Unicem and Calibra groups demonstrated no significant difference in the percentage of silver penetration, while the BisCem group revealed a significantly higher percentage (P≤.05). Thermocycling (500 cycles) did not have a statistically significant effect on the percentage of silver penetration (P>.05). Conclusions: One self-adhesive-resin cement demonstrated a similar sealing ability when compared with a standard resin cement. Thermo-cycling did not significantly increase dye penetration under the test conditions. PMID:21769269

Innovations in bonding to zirconia based ceramics: Part III. Phosphate monomer resin cements.

PubMed

Mirmohammadi, Hesam; Aboushelib, Moustafa N M; Salameh, Ziad; Feilzer, Albert J; Kleverlaan, Cornelis J

2010-08-01

To compare the bond strength values and the ranking order of three phosphate monomer containing resin cements using microtensile (microTBS) and microshear (microSBS) bond strength tests. Zirconia discs (Procera Zirconia) were bonded to resin composite discs (Filtek Z250) using three different cements (Panavia F 2.0, RelyX UniCem, and Multilink). Two bond strength tests were used to determine zirconia resin bond strength; microtensile bond strength test (microTBS) and microshear bond strength test (microSBS). Ten specimens were tested for each group (n=10). Two-way analysis of variance (ANOVA) was used to analyze the data (alpha=0.05). There were statistical significant differences in bond strength values and in the ranking order obtained using the two test methods. microTBS reported significant differences in bond strength values, whereas microSBS failed to detect such effect. Both Multilink and Panavia demonstrated basically cohesive failure in the resin cement while RelyX UniCem demonstrated interfacial failure. Based on the findings of this study, the data obtained using either microTBS or microSBS could not be directly compared. microTBS was more sensitive to material differences compared to microSBS which failed to detect such differences. Copyright 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Impact of Gluma Desensitizer on the tensile strength of zirconia crowns bonded to dentin: an in vitro study.

PubMed

Stawarczyk, Bogna; Hartmann, Leonie; Hartmann, Rahel; Roos, Malgorzata; Ender, Andreas; Ozcan, Mutlu; Sailer, Irena; Hämmerle, Christoph H F

2012-02-01

This study tested the impact of Gluma Desensitizer on the tensile strength of zirconia crowns bonded to dentin. Human teeth were prepared and randomly divided into six groups (N = 144, n = 24 per group). For each tooth, a zirconia crown was manufactured. The zirconia crowns were cemented with: (1) Panavia21 (PAN), (2) Panavia21 combined with Gluma Desensitizer (PAN-G), (3) RelyX Unicem (RXU), (4) RelyX Unicem combined with Gluma Desensitizer (RXU-G), (5) G-Cem (GCM) and (6) G-Cem combined with Gluma Desensitizer (GCM-G). The initial tensile strength was measured in half (n = 12) of each group and the other half (n = 12) subjected to a chewing machine (1.2 Mio, 49 N, 5°C/50°C). The cemented crowns were pulled in a Universal Testing Machine (1 mm/min, Zwick Z010) until failure occurred and tensile strength was calculated. Data were analyzed with one-way and two-way ANOVA followed by a post hoc Scheffé test, t test and Kaplan-Meier analysis with a Breslow-Gehan analysis test (α = 0.05). After the chewing simulation, the self-adhesive resin cements combined with Gluma Desensitizer showed significantly higher tensile strength (RXU-G, 12.8 ± 4.3 MPa; GCM-G, 13.4 ± 6.2 MPa) than PAN (7.3 ± 1.7 MPa) and PAN-G (0.9 ± 0.6). Within the groups, PAN, PAN-G and RXU resulted in significantly lower values when compared to the initial tensile strength; the values of all other test groups were stable. In this study, self-adhesive resin cements combined with Gluma Desensitizer reached better long-term stability compared to PAN and PAN-G after chewing simulation.

Bond strength of self-adhesive resin cements to composite submitted to different surface pretreatments.

PubMed

Dos Santos, Victor Hugo; Griza, Sandro; de Moraes, Rafael Ratto; Faria-E-Silva, André Luis

2014-02-01

Extensively destroyed teeth are commonly restored with composite resin before cavity preparation for indirect restorations. The longevity of the restoration can be related to the proper bonding of the resin cement to the composite. This study aimed to evaluate the microshear bond strength of two self-adhesive resin cements to composite resin. COMPOSITE DISCS WERE SUBJECT TO ONE OF SIX DIFFERENT SURFACE PRETREATMENTS: none (control), 35% phosphoric acid etching for 30 seconds (PA), application of silane (silane), PA + silane, PA + adhesive, or PA + silane + adhesive (n = 6). A silicone mold containing a cylindrical orifice (1 mm(2) diameter) was placed over the composite resin. RelyX Unicem (3M ESPE) or BisCem (Bisco Inc.) self-adhesive resin cement was inserted into the orifices and light-cured. Self-adhesive cement cylinders were submitted to shear loading. Data were analyzed by two-way ANOVA and Tukey's test (p < 0.05). Independent of the cement used, the PA + Silane + Adhesive group showed higher microshear bond strength than those of the PA and PA + Silane groups. There was no difference among the other treatments. Unicem presented higher bond strength than BisCem for all experimental conditions. Pretreatments of the composite resin surface might have an effect on the bond strength of self-adhesive resin cements to this substrate.

In vitro shear bond strength of cementing agents to fixed prosthodontic restorative materials.

PubMed

Piwowarczyk, Andree; Lauer, Hans-Christoph; Sorensen, John A

2004-09-01

Durable bonding to fixed prosthodontic restorations is desirable; however, little information is available on the strength of the bond between different cements and fixed prosthodontic restorative materials. This study determined the shear-bond strength of cementing agents to high-gold-content alloy castings and different dental ceramics: high-strength aluminum oxide (Procera AllCeram), leucite-reinforced (IPS Empress), and lithium disilicate glass-ceramic (IPS Empress 2). Prepolymerized resin composite cylinders (5.5 mm internal diameter, n=20) were bonded to the pretreated surfaces of prosthodontic materials. High-gold-content alloy and high-strength aluminum oxide surfaces were airborne-particle-abraded, and pressable ceramics were hydrofluoric acid-etched and silanized prior to cementing. The cementing agents tested were a zinc-phosphate cement (Fleck's zinc cement), glass ionomer cements (Fuji I, Ketac-Cem), resin-modified glass ionomer cements (Fuji Plus, Fuji Cem, RelyX Luting), resin cements (RelyX ARC, Panavia F, Variolink II, Compolute), and a self-adhesive universal resin cement (RelyX Unicem). Half the specimens (n=10) were tested after 30 minutes; the other half (n=10) were stored in distilled water at 37 degrees C for 14 days and then thermal cycled 1000 times between 5 degrees C and 55 degrees C prior to testing. Shear-bond strength tests were performed using a universal testing machine at a constant crosshead speed of 0.5 mm/min. Statistical analysis was performed by multifactorial analysis of variance taking interactions between effects into account. For multiple paired comparisons, the Tukey method was used (alpha=.05). In a 3-way ANOVA model, the main factors substrate, cement, time, and all corresponding interactions were statistically significant (all P <.0001). In subsequent separate 1-way or 2-way ANOVA models for each substrate type, significant differences between cement types and polymerizing modes were found (all P <.001). None of the cement types provided the highest bonding values with all substrate types. After 14 days of water storage followed by thermal cycling, only the self-adhesive universal resin cement (RelyX Unicem) and 2 of the resin cements (Panavia F and Compolute) exhibited strong bond strengths to specific prosthodontic materials. In contrast, zinc-phosphate, glass ionomer, and resin-modified glass ionomer cements showed the lowest values of all tested cementing agents after 14 days of water storage followed by thermal cycling.

Bond strength of luting cement to casting and soldering alloy.

PubMed

Kumbuloglu, O; Lassila, L V J; User, A; Toksavul, S; Vallittu, P K

2006-03-01

Adjustment of metal alloy framework of the porcelain-fused-to-metal crown by soldering minor marginal deficiences prior insertion may sometimes be needed. The aim of this study was to compare shear bond strengths of four luting cements to casting metal alloy and soldering metal alloy. A total of 64 flame cast non-precious metal alloy and flame soldered metal alloy samples were used. Durelon, Panavia F, RelyX Unicem Applicap and RelyX ARC stubs were bonded to the alloy substrate surface. After stored in water at 37 degrees C for 1 week, shear bond strength of the cement to the alloy was measured. Differences were analyzed using one way ANOVA (p<0.05). There were no difference between the cast metal alloy and soldering metal alloy substrate.

Discolouration of orthodontic adhesives caused by food dyes and ultraviolet light.

PubMed

Faltermeier, Andreas; Rosentritt, Martin; Reicheneder, Claudia; Behr, Michael

2008-02-01

Enamel discolouration after debonding of orthodontic attachments could occur because of irreversible penetration of resin tags into the enamel structure. Adhesives could discolour because of food dyes or ultraviolet irradiation. The aim of this study was to investigate the colour stability of adhesives during ultraviolet irradiation and exposure to food colourants. Four different adhesives were exposed in a Suntest CPS+ ageing device to a xenon lamp to simulate natural daylight (Transbond XT, Enlight, RelyX Unicem, and Meron Plus AC). Tomato ketchup, Coca Cola, and tea were chosen as the food colourants. After 72 hours of exposure, colour measurements were performed by means of a spectrophotometer according to the Commission Internationale de l'Eclairage L*a*b* system and colour changes (DeltaE*) were computed. Statistical differences were investigated using two-way analysis of variance (ANOVA) and Friedman test. Unsatisfactory colour stability after in vitro exposure to food colourants and ultraviolet light was observed for the conventional adhesive systems, Transbond XT and Enlight. RelyX Unicem showed the least colour change and the resin-reinforced glass-ionomer cement (GIC), Meron Plus AC, the greatest colour change. The investigated adhesives seem to be susceptible to both internal and external discolouration. These in vitro findings indicate that the tested conventional adhesive systems reveal unsatisfactory colour stability which should be improved to avoid enamel discolouration.

Comparative study of enamel adhesion between RelyX™ Unicem® (3M), a self-adhesive bonding agent, and the combination of MIP® (3M), a hydrophilic adhesive, and Transbond Supreme Low Viscosity® (3M), a traditional hydrophobic adhesive.

PubMed

Dubernard, Charles; Raynal, Perrine; Tramini, Paul

2013-09-01

Although the bond strength of self-adhesive bonding agents is inferior to that of other families of adhesives, it is still adequate for orthodontic purposes provided prior enamel etching is performed. To determine the efficacy of RelyX™ Unicem(®) (3M) self-adhesive cement both in vitro and in vivo and to compare it with the combination of MIP(®) (3M), a moisture-insensitive primer, with a traditional hydrophobic adhesive, Transbond Supreme Low Viscosity(®) (3M). Comparison of bonding results on 23 trial dentures using RelyX™ Unicem(®) (3M) with bonding results on 29 trial dentures using a combination of MIP(®) and Transbond Supreme Low Viscosity(®) (3M), by means of a multipurpose Instron(®) 4444 testing machine. the breaking force of MIP(®)/Transbond Supreme Low Viscosity(®) (3M) (mean: 144±37.5 Newtons) was significantly higher than that of RelyX™ Unicem(®) (3M) (mean=110±26 Newtons) (P=0.001). A 12-month prospective, randomized, monocentric, single-blind clinical study in order to investigate the failure rate of orthodontic attachments according to the type of adhesive used, and the precise site of the debonding. Bracket bonding was performed on 16 patients with randomized allocation of the two adhesives to each of the semi-arches. The failure rates were: 15.3% for the MIP(®)/Transbond Supreme Low Viscosity(®) (3M) combination and 8.2% for the RelyX™ Unicem(®) (3M), with a significant difference (P=0.039). The more posterior the bonded teeth, the greater the superiority of RelyX™ Unicem(®) (3M). The in vivo results did not concord with those obtained in vitro. RelyX™ Unicem(®) (3M) exhibited lower adhesion values in vitro and yet it presented a debonding rate almost half that of the MIP(®)/Transbond Supreme Low Viscosity(®) (3M). The viscosity of RelyX™ Unicem(®) (3M) and its moisture tolerance would appear to account for these results. With prior etching, RelyX™ Unicem(®) (3M), a self-adhesive, self-etching bonding agent is compatible with use in the orthodontic indirect bonding technique. The MIP(®)/Transbond Supreme Low Viscosity(®) (3M) combination, though very effective, still remains sensitive and requires special care during usage. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Cytotoxicity of four categories of dental cements.

PubMed

Schmid-Schwap, Martina; Franz, Alexander; König, Franz; Bristela, Margit; Lucas, Trevor; Piehslinger, Eva; Watts, David C; Schedle, Andreas

2009-03-01

Assessment of dental material biocompatibility is gaining increasing importance for both patients and dentists. Dental cements may be in contact with oral soft tissues for prolonged periods of time and play an important role in prosthetic rehabilitation. The aim of the present study was to evaluate eight dental cements using a standardized L929-fibroblast cell culture test. For each material, fresh specimens (added to the cultures immediately after preparation) and specimens preincubated for 7 days in cell culture medium were prepared according to the manufacturers' recommendations. After exposure to test specimens, cell numbers were compared to glass controls. The main outcome was a two-sided 95% confidence interval for the mean value of the standardized cell number for each substance investigated. Fresh specimens of all tested cements showed significant cytotoxicity, which diminished after 7 days preincubation. Cytotoxicity of fresh adhesive and self-adhesive resin cements was lower when specimens were dual-cured compared to self-cured. A rank order of cytotoxicity was established based on mean values: Nexus 2 (dual-cured) showed least cytotoxicity, followed by Variolink II (dual-cured), Nexus 2 (self-cured), Harvard, RelyxUnicem (dual-cured), Panavia 21, Fujicem, Durelon, Variolink II (self-cured), RelyxUnicem (self-cured), Maxcem (dual-cured) and Maxcem (self-cured). When bondings were added to Nexus 2 or Variolink II specimens, a slight increase in cytotoxicity was observed. Adhesive resin cements showed less cytotoxicity than self-adhesive and chemically setting cements. Bonding only slightly influenced cytotoxicity of the adhesive resin cements. Dual-cured specimens of adhesive and self-adhesive resin cements showed significantly less toxicity than self-cured specimens.

The influence of time and cement type on push-out bond strength of fiber posts to root dentin.

PubMed

Leme, A A; Coutinho, M; Insaurralde, A F; Scaffa, P M C; da Silva, L M

2011-01-01

The bond strength of fiber posts luted with resin cements was evaluated after two storage times in different regions of a post space. A total of 40 single-rooted human teeth were endodontically treated and prepared for cementation of fiber posts (White Post DC). In groups 1 and 3 (G1 and G3, respectively), posts were luted with RelyX ARC, whereas the posts in groups 2 and 4 (G2 and G4, respectively) were luted with RelyX Unicem. After one month of storage at 100% humidity, G1 and G2 were transversally sectioned in 1.7-mm slices of the cervical (C), middle (M), and apical (A) thirds of the post space and submitted to push-out testing at 1 mm/min. After nine months of storage, the roots of G3 and G4 underwent the same process. Mean values were analyzed using the Mann-Whitney and Kruskal-Wallis tests (α=0.05). The bond strengths in G2 (C=4.26±2.29; M=4.67±3.54; A=7.27±4.30) were statistically higher than in G1 (C=3.81±1.07; M=1.57±1.62; A=1.99±1.60) in the middle and apical thirds (p=0.001). Bond strengths in G4 (C=3.36±1.39; M=4.49±2.17; A=3.83±1.92) were higher than in G3 (C=2.13±0.47; M=0.94±1.05; A=0.95±1.02) in all evaluated regions (p=0.02, p<0.001, and p<0.001, respectively). When comparing the root regions for each group, G1 had higher values in the cervical third than the middle third (p=0.02). The self-adhesive resin cement showed better results than the conventional resin cement at both storage times. For both materials a similar performance among the three root regions was found. Storage time did not influence the shear bond strength.

Physical properties and comparative strength of a bioactive luting cement.

PubMed

Jefferies, Steven; Lööf, Jesper; Pameijer, Cornelis H; Boston, Daniel; Galbraith, Colin; Hermansson, Leif

2013-01-01

New dental cement formulations require testing to determine physical and mechanical laboratory properties. To test an experimental calcium aluminate/glass-ionomer cement, Ceramir C and B (CC and B), regarding compressive strength (CS), film thickness (FT), net setting time (ST) and Vickers hardness. An additional test to evaluate potential dimensional change/expansion properties of this cement was also conducted. CS was measured according to a slightly modified ISO 9917:2003 for the CC and B specimens. The samples were not clamped while being exposed to relative humidity of great than 90 percent at 37 degrees C for 10 minutes before being stored in phosphate-buffered saline at 37 degrees C. For the CS, four groups were tested: Group 1-CC and B; Group 2-RelyX Luting Cement; Group 3-Fuji Plus; and Group 4-RelyX Unicem. Samples from all groups were stored for 24 hours before testing. Only CCandB was tested for ST and FT according to ISO 9917:2003. The FT was tested 2 minutes after mixing. Vickers hardness was evaluated using the CSM Microhardness Indentation Tester using zinc phosphate cement as a comparison material. Expansion testing included evaluating potential cracks in feldspathic porcelain jacket crowns (PJCs). The mean and standard deviation after 24 hours were expressed in MPa: Group 1 equals 160 plus or equal to 27; Group 2 equals 96 plus or equal to 10; Group 3 equals 138 plus or equal to 15; Group 4 equals 157 plus or equal to 10. A single-factor ANOVA demonstrated statistically significant differences between the groups (P less than 0.001). Pair-wise statistical comparison demonstrated a statistically significant difference between Groups 1 and 2. No statistically significant differences were found between other groups. The FT was 16.8 plus or equal to 0.9 and the ST was 4.8 plus or equal to 0.1 min. Vickers hardness for Ceramir C and B was 68.3 plus or equal to 17.2 and was statistically significantly higher (P less than 0.05) than Fleck's Zinc Phosphate cement at Vickers hardness of 51.4 plus or equal to 10. There was no evidence of cracks due to radial expansion in PJCs by the Ceramir C and B cement. All luting cements tested demonstrated compressive strengths well in excess of the ISO requirement for water-based cements of no less than 50 MPa. Ceramir C and B showed significantly higher CS than RelyX Luting Cement after 24 hours, but was not significantly higher than either Fuji Plus or RelyX Unicem. The ST and FT values of CC and B conform to and are within the boundaries of the requirements of the standard. Surface hardness was statistically higher than and comparable to zinc phosphate cement. There was no evidence of potentially clinically significant and deleterious expansion behavior by this cement. All cements tested demonstrated acceptable strength properties. Within the limits of this study, Ceramir C and B is deemed to possess physical properties suitable for a dental luting cement.

Ultrasonic measurement of the effects of light irradiation and presence of water on the polymerization of self-adhesive resin cement.

PubMed

Takenaka, Hirotaka; Ouchi, Hajime; Sai, Keiichi; Kawamoto, Ryo; Murayama, Ryosuke; Kurokawa, Hiroyasu; Miyazaki, Masashi

2015-08-14

Self-adhesive resin cements are useful in restorations because they reduce the number of clinical steps involved in the restoration process. This study evaluated, using ultrasonic measurements, the influence of light irradiation and the presence of water on the polymerization behavior and elastic modulus of a self-adhesive resin cement. A self-adhesive resin cement (RelyX Unicem 2 Automix) or a resin cement (RelyX ARC) was inserted into a transparent mold on a sample stage, and the presence of water and effect of light-irradiation were evaluated. The transit time of a sonic wave through the cement disk was divided by the specimen thickness to obtain the sonic velocity, and longitudinal and shear waves were used to determine the elastic modulus. When the resin cements were light-irradiated, the sonic velocity rapidly increased and plateaued at 2,500-2,700 m s -1 . When the cements were not irradiated, the rates of increase in the sonic velocity were reduced. When water was applied to the sample stage, the sonic velocity was reduced. The elastic modulus values of the specimens ranged from 9.9 to 15.9 GPa after 24 h. The polymerization behavior of self-adhesive resin cements is affected by the polymerization mode and the presence of water. © 2015 Eur J Oral Sci.

Dual and self-curing potential of self-adhesive resin cements as thin films.

PubMed

Moraes, R R; Boscato, N; Jardim, P S; Schneider, L F J

2011-01-01

In this study, the dual- and self-curing potential of self-adhesive resin cements (SARCs) as thin, clinically-relevant cement films was investigated. The SARCs tested were: BisCem (BSC; Bisco), Maxcem Elite (MXE; Kerr), RelyX Unicem clicker (UNI; 3M ESPE), seT capsule (SET; SDI), and SmartCem 2 (SC2; Dentsply Caulk). The conventional cement RelyX ARC (3M ESPE) was tested as a reference. The degree of conversion (DC) as a function of time was evaluated by real-time Fourier transform infrared spectroscopy with an attenuated total reflectance (ATR) device. The cements were either photoactivated for 40 seconds (dual-cure mode) or not photoactivated (self-cure mode). The cement film thickness was 50 ± 10 μm. The DC (%) was evaluated 1, 5, 10, 15, 20, 25, and 30 minutes after placing the cement on the ATR cell. Data for DC as a function of time were analyzed by two-way repeated measures analysis of variance (ANOVA). DC values at 30 minutes for the self- and dual-cure modes were submitted to one-way ANOVA. Post hoc comparisons were performed using the Student-Newman-Keuls test (p<0.05). The rate and the extent of conversion were lower for the SARCs compared with the conventional cement. Means ± standard deviations (SD) for the dual-cure mode at 30 minutes were: 75 ± 5 (ARC)a, 73 ± 8 (SET)a, 61 ± 4 (MXE)b, 51 ± 9 (BSC)c, 51 ± 4 (UNI)c, and 48 ± 3 (SC2)c, while in the self-cure mode means and SD were 62 ± 6 (ARC)a, 54 ± 3 (MXE)b, 40 ± 6 (SC2)c, 35 ± 2 (UNI)c, 35 ± 3 (SET)c, and 11 ± 3 (BSC)d. The DC for the dual-cure mode was generally higher than the self-cure, irrespective of the time. Discrepancies in DC between the dual- and self-cure modes from 11% to 79% were observed. In conclusion, SARCs may present slower rate of polymerization and lower final DC than conventional resin cements, in either the dual- or self-cure mode.

Mechanical properties of components of the bonding interface in different regions of radicular dentin surfaces.

PubMed

Suzuki, Thaís Yumi Umeda; Gomes-Filho, João Eduardo; Gallego, Juno; Pavan, Sabrina; Dos Santos, Paulo Henrique; Fraga Briso, André Luiz

2015-01-01

The mechanical properties of the adhesive materials used in intraradicular treatments could vary according to the interaction between the restorative material and dentin substrate. An evaluation of these properties is essential to determine the success of the luting procedures performed on glass-fiber posts. The purpose of this study was to evaluate the mechanical properties of dentin adhesives, resin cements, and the dentin that underlies the bonding interface in different thirds of intraradicular dentin. Forty extracted, single-rooted human teeth were used in this study. After the endodontic treatment of the post spaces, the teeth were divided into 5 groups (n=8): Adper Single Bond 2 + RelyX ARC, Excite DSC + RelyX ARC, Adper SE Plus + RelyX ARC, RelyX Unicem, and Set. The hardness and elastic modulus values were measured at the adhesive interface in different thirds of the radicular dentin by using an ultramicrohardness tester. The data were subjected to 2-way ANOVA and the Fisher protected least significant difference test (α=.05). In the underlying dentin, the highest Martens hardness values were found in the apical region for all groups; the exceptions were the groups with the self-etching adhesive. In the adhesive layer, the highest Martens hardness values were obtained for the Adper SE Plus + RelyX ARC group; further, no statistical differences were found among the different regions for this group. RelyX ARC had the lowest Martens hardness and elastic modulus values in the apical regions when used with Adper Single Bond 2 and Adper SE Plus. No differences were found in the Martens hardness and elastic modulus values for the self-adhesive resin cement in the regions investigated. The mechanical properties of adhesive materials and the underlying dentin are influenced by the interaction between the two as well as by the depth of the analyzed intraradicular area. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

The effect of different surface treatments on the shear bond strength of luting cements to titanium.

PubMed

Abi-Rached, Filipe de Oliveira; Fonseca, Renata Garcia; Haneda, Isabella Gagliardi; de Almeida-Júnior, Antonio Alves; Adabo, Gelson Luis

2012-12-01

Although titanium presents attractive physical and mechanical properties, there is a need for improving the bond at the titanium/luting cement interface for the longevity of metal ceramic restorations. The purpose of this study was to evaluate the effect of surface treatments on the shear bond strength (SBS) of resin-modified glass ionomer and resin cements to commercially pure titanium (CP Ti). Two hundred and forty CP Ti cast disks (9.0 × 3.0 mm) were divided into 8 surface treatment groups (n=30): 1) 50 µm Al(2)O(3) particles; 2) 120 µm Al(2)O(3) particles; 3) 250 µm Al(2)O(3) particles; 4) 50 µm Al(2)O(3) particles + silane (RelyX Ceramic Primer); 5) 120 µm Al(2)O(3) particles + silane; 6) 250 µm Al(2)O(3) particles + silane; 7) 30 µm silica-modified Al(2)O(3) particles (Cojet Sand) + silane; and 8) 120 µm Al(2)O(3) particles, followed by 110 µm silica-modified Al(2)O(3) particles (Rocatec). The luting cements 1) RelyX Luting 2; 2) RelyX ARC; or 3) RelyX U100 were applied to the treated CP Ti surfaces (n=10). Shear bond strength (SBS) was tested after thermal cycling (5000 cycles, 5°C to 55°C). Data were analyzed by 2-way analysis of variance (ANOVA) and the Tukey HSD post hoc test (α=.05). Failure mode was determined with a stereomicroscope (×20). The surface treatments, cements, and their interaction significantly affected the SBS (P<.001). RelyX Luting 2 and RelyX U100 exhibited similar behavior for all surface treatments. For both cements, only the group abraded with 50 μm Al(2)O(3) particles had lower SBS than the other groups (P<.05). For RelyX ARC, regardless of silane application, abrasion with 50 μm Al(2)O(3) particles resulted in significantly lower SBS than abrasion with 120 μm and 250 μm particles, which exhibited statistically similar SBS values to each other. Rocatec + silane promoted the highest SBS for RelyX ARC. RelyX U100 presented the highest SBS mean values (P<.001). All groups showed a predominance of adhesive failure mode. The adhesive capability of RelyX Luting 2 and RelyX U100 on the SBS was decisive, while for RelyX ARC, mechanical and chemical factors were more influential. Copyright © 2012 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Retention Forces between Titanium and Zirconia Components of Two-Part Implant Abutments with Different Techniques of Surface Modification.

PubMed

von Maltzahn, Nadine Freifrau; Holstermann, Jan; Kohorst, Philipp

2016-08-01

The adhesive connection between titanium base and zirconia coping of two-part abutments may be responsible for the failure rate. A high mechanical stability between both components is essential for the long-term success. The aim of the present in-vitro study was to evaluate the influence of different surface modification techniques and resin-based luting agents on the retention forces between titanium and zirconia components in two-part implant abutments. A total of 120 abutments with a titanium base bonded to a zirconia coping were investigated. Two different resin-based luting agents (Panavia F 2.0 and RelyX Unicem) and six different surface modifications were used to fix these components, resulting in 12 test groups (n = 10). The surface of the test specimens was mechanically pretreated with aluminium oxide blasting in combination with application of two surface activating primers (Alloy Primer, Clearfil Ceramic Primer) or a tribological conditioning (Rocatec), respectively. All specimens underwent 10,000 thermal cycles between 5°C and 55°C in a moist environment. A pull-off test was then conducted to determine retention forces between the titanium and zirconia components, and statistical analysis was performed (two-way anova). Finally, fracture surfaces were analyzed by light and scanning electron microscopy. No significant differences were found between Panavia F 2.0 and RelyX Unicem. However, the retention forces were significantly influenced by the surface modification technique used (p < 0.001). For both luting agents, the highest retention forces were found when adhesion surfaces of both the titanium bases and the zirconia copings were pretreated with aluminium oxide blasting, and with the application of Clearfil Ceramic Primer. Surface modification techniques crucially influence the retention forces between titanium and zirconia components in two-part implant abutments. All adhesion surfaces should be pretreated by sandblasting. Moreover, a phosphate-based primer serves to enhance long-term retention of the components. © 2015 Wiley Periodicals, Inc.

IPS Empress inlays luted with a self-adhesive resin cement after 1 year.

PubMed

Taschner, Michael; Frankenberger, Roland; García-Godoy, Franklin; Rosenbusch, Silke; Petschelt, Anselm; Krämer, Norbert

2009-02-01

To prospectively compare the clinical performance of two different resin composites for luting IPS Empress inlays and onlays. 83 IPS Empress restorations were placed in 30 subjects. All restorations were inserted under rubber dam. 43 inlays/onlays were luted with a self-adhesive resin cement [RelyX Unicem (RX)]. A multistep adhesive (Syntac) was used with Variolink II low viscosity (SV) and served as control (n=40). The restorations were evaluated after 2 weeks: Baseline = 1st recall (R1), after 6 months (R2) and after 1 year (R3) by two calibrated examiners using the modified USPHS criteria. From R1 to R3, one failure was noticed in the SV group (R2) due to marginal enamel chipping. After 1 year of clinical service, SV revealed significantly better results regarding color match and integrity inlay (Mann-Whitney U-test, P< 0.05). No statistically significant differences were observed between SV and RX for the remaining criteria (Mann-Whitney U-test, P>0.05).

The improvement of adhesive properties of PEEK through different pre-treatments

NASA Astrophysics Data System (ADS)

Hallmann, Lubica; Mehl, Albert; Sereno, Nuno; Hämmerle, Christoph H. F.

2012-07-01

The purpose of this in vitro study was the evaluation of the bond strength of the adhesives/composite resin to Poly Ether Ether Ketone (PEEK) based dental polymer after using different surface conditioning methods. PEEK blanks were cut into discs. All disc specimens were polished with 800 grit SiC paper and divided into 6 main groups. Main groups were divided into 2 subgroups. The main groups of 32 specimens each were treated as follow: (1) control specimens (no treatment), (2) piranha solution etching, (3) abraded with 50 μm alumina particles and chemical etching, (4) abraded with 110 μm alumina particles and chemical etching, (5) abraded with 30 μm silica-coated alumina particles and chemical etching, (6) abraded with 110 μm silica-coated alumina particles and chemical etching. Plexiglas tubes filled with a composite resin (RelyX Unicem) were bonded to the specimens. The adhesives used were Heliobond and Clearfil Ceramic Primer. Each specimen was stored in distilled water (37 °C) for 3 days. Tensile bond strength was measured in a universal testing machine and failure methods were evaluated. Abraded surface with 50 μm alumina particles followed by etching with piranha solution lead to the highest bond strength of 21.4 MPa when Heliobond like adhesive was used. Tribochemical silica coated/etched PEEK surfaces did not have an effect on the bond strength. Non-treated PEEK surface was not able to establish a bond with composite resin. The proper choice of adhesive/composite resin system leads to a strong bond. ConclusionAirborne particle abrasion in combination with piranha solution etching improves the adhesive properties of PEEK.

Comparison of shear bond strength of self-etch and self-adhesive cements bonded to lithium disilicate, enamel and dentin.

PubMed

Naranjo, Jennifer; Ali, Mohsin; Belles, Donald

2015-11-01

Comparison of shear bond strength of self-etch and self-adhesive cements bonded to lithium disilicate, enamel and dentin. With several self-adhesive resin cements currently available, there is confusion about which product and technique is optimal for bonding ceramic restorations to teeth. The objective of this study was to compare the shear bond strength of lithium disilicate cemented to enamel and dentin using 5 adhesive cements. 100 lithium disilicate rods were pretreated with 5% hydrofluoric acid, silane, and cemented to 50 enamel and 50 dentin surfaces using five test cements: Variolink II (etch-and-rinse) control group, Clearfil Esthetic (two step self-etch), RelyX Unicem, SpeedCEM, and BifixSE (self-adhesive). All specimens were stored (37 degrees C, 100% humidity) for 24 hours before testing their shear bond strength using a universal testing machine (Instron). Debonded surfaces were observed under a low-power microscope to assess the location and type of failure. The highest bond strength for both enamel and dentin were recorded for Variolink II, 15.1MPa and 20.4MPa respectively, and the lowest were recorded for BifixSE, 0.6MPa and 0.9MPa respectively. Generally, higher bond strengths were found for dentin (7.4MPa) than enamel (5.3MPa). Tukey's post hoc test showed no significant difference between Clearfil Esthetic and SpeedCem (p = 0.059), Unicem and SpeedCem (p = 0.88), and Unicem and BifixSE (p = 0.092). All cements bonded better to lithium disilicate than to enamel or dentin, as all bond failures occurred at the tooth/adhesive interface except for Variolink II. Bond strengths recorded for self-adhesive cements were very low compared to the control "etch and rinse" and self-etch systems. Further improvements are apparently needed in self-adhesive cements for them to replace multistep adhesive systems. The use of conventional etch and rinse cements such as Veriolink II should be preferred for cementing all ceramic restorations over self-adhesive cements until the bond strengths are improved.

Influence of nano-structured alumina coating on shear bond strength between Y-TZP ceramic and various dual-cured resin cements.

PubMed

Lee, Jung-Jin; Choi, Jung-Yun; Seo, Jae-Min

2017-04-01

The purpose of this study was to evaluate the effect of nano-structured alumina surface coating on shear bond strength between Y-TZP ceramic and various dual-cured resin cements. A total of 90 disk-shaped zirconia specimens (HASS CO., Gangneung, Korea) were divided into three groups by surface treatment method: (1) airborne particle abrasion, (2) tribochemicalsilica coating, and (3) nano-structured alumina coating. Each group was categorized into three subgroups of ten specimens and bonded with three different types of dual-cured resin cements. After thermocycling, shear bond strength was measured and failure modes were observed through FE-SEM. Two-way ANOVA and the Tukey's HSD test were performed to determine the effects of surface treatment method and type of cement on bond strength ( P <.05). To confirm the correlation of surface treatment and failure mode, the Chi-square test was used. Groups treated with the nanostructured alumina coating showed significantly higher shear bond strength compared to other groups treated with airborne particle abrasion or tribochemical silica coating. Clearfil SA Luting showed a significantly higher shear bond strength compared to RelyX ARC and RelyX Unicem. The cohesive failure mode was observed to be dominant in the groups treated with nano-structured alumina coating, while the adhesive failure mode was prevalent in the groups treated with either airborne particle abrasion or tribochemical silica coating. Nano-structured alumina coating is an effective zirconia surface treatment method for enhancing the bond strength between Y-TZP ceramic and various dual-cured resin cements.

Adhesive bonding to polymer infiltrated ceramic.

PubMed

Schwenter, Judith; Schmidli, Fredy; Weiger, Roland; Fischer, Jens

2016-01-01

Aim of this study was to investigate the mechanism of adhesive bonding to the polymer-infiltrated ceramic VITA Enamic [VE]. Shear bond strength was measured with three resin composite cements: RelyX Unicem 2 Automix, Clearfil SA and Variolink II on polished surfaces of VE and its components silicate ceramic [SC] and polymer [PM] (n=12). Further, the effect of etching VE with 5% HF for 15-240 s and the application of silane coupling agents was analyzed in a screening test (n=6). Shear bond strength measurements were performed after 24 h of water storage at 37°C. Significant bonding to polished substrates could only be achieved on VE and SC when silane coupling agents were used. Etching of VE with 5% HF increased shear bond strength. Following silanization of etched VE, a further increase in shear bond strength could be established. Etching for more than 30 s did not improve shear bond strength.

[Bonding properties of four different cements to glass fiber posts after different treatments].

PubMed

Li, Xiaojing; Zhao, Sanjun; Shen, Lijuan; Xu, Shuai; Sun, Jiaqi; Chen, Jihua

2014-03-01

To investigate the effect of four different cements on the bonding effectiveness of root canal dentine and fiber post before and after different treatments. A total of 216 freshly extracted sound single-root-canal mandibular premolars were randomly divided into four groups. After root canal treatment and post space preparation being conducted on the premolars, Fuji I, Fuji Cem, RelyX Unicem, RelyX ARC were used respectively to bond fiber posts and were marked with group A, B, C, and D. Microleakage, micromorphology of the bonded interfaces, and pull-out bond strength were evaluated in the immediate group, thermocycling group and thermomechanical loading group. In the immediate group, samples in group D showed the highest bond strength [(278 ± 26)N], followed by group C[ (219 ± 12) N], B[ (104 ± 23) N] and A[(73 ± 8) N]. Significant differences were found among all groups (P < 0.05) . A significant increase in bond strength was found in group A and B, whereas a decrease tendency was detected in group C and D after different treatments.Scanning electron microscope indicated that some little gaps were observed in group D after treatment, while a more intense bonding interface was found in group A and B. Microleakage scores in group A and B were lower than those in group C and D after aging treatments. Resin cement can achieve a better immediate bond strength, while resin-modified resin cement may acquire a better long-term retention.

Effect of saliva contamination and artificial aging on different primer/cement systems bonded to zirconia.

PubMed

Pitta, João; Branco, Teresa C; Portugal, Jaime

2018-05-01

Saliva contamination has been shown to decrease bonding to zirconia. Adopting a less contamination-sensitive cement system may be an alternative to decontamination. The purpose of this in vitro study was to assess the ability of different primer/cement systems to promote a durable bond to zirconia after saliva contamination. Zirconia blocks (Lava Plus) (N=320) were airborne-particle abraded (50 μm Al 2 O 3 ) and divided into 32 experimental groups (n=10) according to the variables in the study: saliva contamination; primer/cement system (Panavia SA [PSA]; RelyX Unicem 2 [RU2]; Bifix SE [BSE]; Panavia F2.0 [PF2]; Scotchbond Universal + RelyX Ultimate [SBU+RXU]; Futurabond M+ + Bifix QM [FBM+BQM]; All-Bond Universal + Duo-link [ABU+DL]; Z-Prime Plus + Duo-link [ZPP+DL]; and aging period (72 hours; 30 days with 10 000 thermocycles at 5°C to 55°C). After half of the blocks had been contaminated with fresh human saliva for 10 minutes, rinsed with water, and air-dried, each primer/cement was applied. Polymerized composite resin disks were then placed over the cement, and the resin cement was light-polymerized for 20 seconds each at 2 opposite margins. After the aging time, the specimens were tested in shear (1 mm/min). The failure mode was classified as adhesive, cohesive, or mixed. Statistical analysis of the shear bond strength (SBS) data was performed with ANOVA followed by Tukey honest significant difference post hoc tests. Chi-square tests were used to analyze the failure mode data (α=.05). The mean SBS ranged between 4.2 and 34.5 MPa. Shear bond strength was influenced (P<.001) by all the factors studied (cement system, saliva contamination, aging time). SBU+RXU and FBM+BQM showed a higher mean SBS than those of the other experimental groups (P<.05) and were the only groups not affected by saliva contamination (P>.05). Failure was predominantly classified as adhesive. In general, saliva contamination and aging decreased bonding efficacy. Two systems, combining an application of a universal adhesive and a resin cement (SBU+RXU and FBM+BQM) were not affected by saliva contamination. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Controlled, prospective, randomized, clinical split-mouth evaluation of partial ceramic crowns luted with a new, universal adhesive system/resin cement: results after 18 months.

PubMed

Vogl, Vanessa; Hiller, Karl-Anton; Buchalla, Wolfgang; Federlin, Marianne; Schmalz, Gottfried

2016-12-01

A new universal adhesive with corresponding luting composite was recently marketed which can be used both, in a self-etch or in an etch-and-rinse mode. In this study, the clinical performance of partial ceramic crowns (PCCs) inserted with this adhesive and the corresponding luting material used in a self-etch or selective etch approach was compared with a self-adhesive universal luting material. Three PCCs were placed in a split-mouth design in 50 patients. Two PCCs were luted with a combination of a universal adhesive/resin cement (Scotchbond Universal/RelyX Ultimate, 3M ESPE) with (SB+E)/without (SB-E) selective enamel etching. Another PCC was luted with a self-adhesive resin cement (RelyX Unicem 2, 3M ESPE). Forty-eight patients were evaluated clinically according to FDI criteria at baseline and 6, 12 and 18 months. For statistical analyses, the chi-square test (α = 0.05) and Kaplan-Meier analysis were applied. Clinically, no statistically significant differences between groups were detected over time. Within groups, clinically significant increase for criterion "marginal staining" was detected for SB-E over 18 months. Kaplan-Meier analysis revealed significantly higher retention rates for SB+E (97.8 %) and SB-E (95.6 %) in comparison to RXU2 (75.6 %). The 18-month clinical performance of a new universal adhesive/composite combination showed no differences with respect to bonding strategy and may be recommended for luting PCCs. Longer-term evaluation is needed to confirm superiority of SB+E over SB-E. At 18 months, the new multi-mode adhesive, Scotchbond Universal, showed clinically reliable results when used for luting PCCs.

Dentin bond strength of two resin-ceramic computer-aided design/computer-aided manufacturing (CAD/CAM) materials and five cements after six months storage.

PubMed

Flury, Simon; Schmidt, Stefanie Zita; Peutzfeldt, Anne; Lussi, Adrian

2016-10-01

The aim was to investigate dentin bond strength of two resin-ceramic materials and five cements after 24 h and six months storage. Cylinders (n=15/group) of Lava Ultimate (3M ESPE) and VITA ENAMIC (VITA Zahnfabrik) were cemented to mid-coronal dentin of 300 extracted human molars with RelyX Ultimate (3M ESPE), PANAVIA F2.0 (Kuraray), Variolink II (Ivoclar Vivadent), els cem (Saremco Dental), or Ketac Cem Plus (3M ESPE). Shear bond strength (SBS) was measured after 24 h or six months storage (37°C, 100% humidity) and statistically analyzed (significance level: α=0.05). SBS varied markedly between Lava Ultimate and VITA ENAMIC, between the five cements, and between storage of either 24 h or six months. After six months, SBS was highest when Lava Ultimate was cemented with RelyX Ultimate and when VITA ENAMIC was cemented with RelyX Ultimate or with Variolink II. Lava Ultimate was somewhat more sensitive to storage than was VITA ENAMIC.

Photoelastic stress analysis of different prefabricated post-and-core materials.

PubMed

Asvanund, Pattapon; Morgano, Steven M

2011-01-01

The purpose of this study was to investigate stress developed by a combination of a stainless steel post or a fiber-reinforced resin post with a silver amalgam core or a composite resin core. Two-dimensional photoelastic models were used to simulate root dentin. Posts (ParaPost XT and ParaPost-FiberWhite) were cemented with a luting agent (RelyX Unicem). Silver amalgam cores and composite resin cores were fabricated on the posts. Complete crowns were fabricated and cemented on the cores. Each model was analyzed with 2 force magnitudes and in 2 directions. Fringe orders were recorded and compared using ANOVA (p=0.05) and the Scheffe's test. With vertical force, no stress differences occurred among the 4 groups (p=0.159). With a 30-degree force, there was stress differences among the 4 groups (p<0.001). The combination of a fiber-reinforced post and composite resin core could potentially reduce stresses within the radicular dentin when angled loads are applied.

Live cell imaging reveals different modes of cytotoxic action of extracts derived from commonly used luting cements.

PubMed

Trumpaitė-Vanagienė, Rita; Čebatariūnienė, Alina; Tunaitis, Virginijus; Pūrienė, Alina; Pivoriūnas, Augustas

2018-02-01

To compare cytotoxicity of extracts derived from commonly used luting cements: Hoffmann's Zinc Phosphate (ZPC), GC Fuji Plus Resin Modified Glass Ionomer (RMGIC) and 3M ESPE RelyX Unicem Resin Cement (RC) on primary human gingival fibroblasts (HGFs). HGFs were exposed to different concentrations of the ZPC, RMGIC and RC extracts. The cytotoxicity was assessed with the PrestoBlue Cell Viability Reagent and viable cells were counted by a haemocytometer using the trypan blue exclusion test. In order to determine the primary mechanism of the cell death induced by extracts from different luting cements, the real-time monitoring of caspase-3/-7 activity and membrane integrity of cells was employed. The extracts from the RMGIC and ZPC decreased the metabolic activity and numbers of viable cells. Unexpectedly, the extracts from the RC evoked only small effects on the metabolic activity of HGFs with a decreasing number of viable cells in a dose-and time-dependent manner. The live cell imaging revealed that the apoptosis was the primary mechanism of a cell death induced by the extracts derived from the RMGIC, whereas the extracts from the RC and ZPC induced a cell death through a necrotic and caspase-independent pathway. The apoptosis was the primary mechanism of the cell death induced by the extracts derived from the RMGIC, whereas the extracts from the RC and ZPC induced a cell death via a necrotic pathway. We suggest that metabolic assays commonly used to assess the cytotoxicity of luting cements should be validated by alternative methods. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effect of photopolymerization on the degree of conversion, polymerization kinetic, biaxial flexure strength, and modulus of self-adhesive resin cements.

PubMed

Aguiar, Thaiane R; de Oliveira, Michele; Arrais, César A G; Ambrosano, Glaucia M B; Rueggeberg, Frederick; Giannini, Marcelo

2015-02-01

Understanding the effect of the degree of conversion on the mechanical properties of auto- and dual-polymerizing self-adhesive resin cements leads to a better estimation of their performance in different clinical scenarios. The purpose of this study was to evaluate the effect of photopolymerization on the degree of conversion (DC) and polymerization kinetic of 4 dual-polymerized resin cements, 20 minutes after mixing, and its effects on the mechanical properties (biaxial flexural strength [FS] and modulus [FM]) after short-term aging. Conventional (RelyX ARC and Clearfil Esthetic Cement) and self-adhesive resin cements (RelyX Unicem and Clearfil SA Cement) were applied to a Fourier infrared spectrometer to assess the DC (n=5) under the following 3 polymerization conditions: direct light exposure (dual-polymerizing mode), exposure through the prepolymerized disk, or autopolymerizing. The polymerization kinetic was recorded for 20 minutes. Then, disk-shaped specimens (n=11) were prepared to evaluate the effect of polymerization on the FS and FM in both extreme polymerization conditions (dual-polymerizing or autopolymerizing). Data were statistically analyzed by 2-way repeated measure ANOVA (DC) and by 2-way ANOVA (FS and FM), followed by the Tukey-Kramer post hoc test (α=.05). Autopolymerizing groups exhibited reduced DC means, whereas intermediate values were observed when resin cements were polymerized through the disk. All groups exhibited higher DC at the end of 20 minutes. The polymerization kinetic revealed a rising curve, and materials, when directly photopolymerized, reached a plateau immediately after light exposure. Regarding the flexural biaxial testing, most of the resin cements were affected by polymerization mode and differences among groups were product dependent. The resin cements achieved immediate higher DC and mechanical properties when photopolymerized. The total absence of photoactivation may still impair their mechanical properties even after short-term aging. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Impact of different adhesives on work of adhesion between CAD/CAM polymers and resin composite cements.

PubMed

Keul, Christine; Müller-Hahl, Manuel; Eichberger, Marlis; Liebermann, Anja; Roos, Malgorzata; Edelhoff, Daniel; Stawarczyk, Bogna

2014-09-01

To determine the impact of pre-treatment of adhesive systems on the work of adhesion (WA) between CAD/CAM polymers and resin composite cements and compare with conventional tests of previous studies. Surface parameters were measured by contact angle measurement (2700 measurements) and WA was calculated. Five CAD/CAM polymers were used for fabrication of specimens (n=75/subgroup): artBloc Temp (A), Telio CAD (B), Nano Composite CFI-C (C), exp. CAD/CAM nanohybrid composite (D), and LAVA Ultimate (E). Then, air-abraded specimens were pre-treated (n=15 per group): Ambarino P60 (I), Monobond Plus/Heliobond (II), visio.link (III), VP connect (IV), and no pre-treatment (V). Resin composite cement specimens (n=75) were smoothed out homogeneously on a glass plate (n=15/group): RelyX ARC (RXA), Variolink II (VAR), Panavia F2.0 (PAN), RelyX Unicem (RXU), and Clearfil SA Cement (CSA). Contact angles were determined with 3 drops of distilled water and diiodomethane each. Data were analyzed using Kruskal-Wallis-H test and Spearman-Rho correlation (p<0.05). CAD/CAM materials (B), (A), and (C) showed higher WA compared to (D) and (E). (II) and (IV) resulted in higher WA than (I), (III) and (V). VAR had the significantly lowest WA, followed by RXU, RXA, CSA and PAN. No correlation occurred between WA and TBS/SBS whereas polar component of surface free energy of CAD/CAM resin and spreading coefficient showed significant positive correlation with TBS/SBS. Determination of WA is not a proper method to draw conclusions about the bond between resin materials. Destructive test methods are not dispensable. The successful outcome of fixed dental restorations depends, among others, on the quality of bonding between the tooth and the restoration. Additional pre-treatment of the dental CAD/CAM resin restoration by bonding systems can be recommended for clinical use. Pre-treatment showed a significant impact on the surface properties. Copyright © 2014 Elsevier Ltd. All rights reserved.

The bacterial adhesion on and the cytotoxicity of various dental cements used for implant-supported fixed restorations.

PubMed

Winkler, Cornelia; Schäfer, Lina; Felthaus, Oliver; Allerdings, Juri; Hahnel, Sebastian; Behr, Michael; Bürgers, Ralf

2014-05-01

Bacterial adhesion on and cytotoxicity of eight luting agents used for implant-supported restorations were investigated. Surface roughness (Ra), surface free energy (SFE) values and three-dimensional images by atomic-force microscopy of circular specimens were determined. Bacterial suspensions of Streptococcus sanguinis and Streptococcus epidermidis were incubated at 37°C for 2 h. Adhering bacteria were examined with fluorescence dye CytoX-Violet, stained with 4',6-diamidino-2-phenylindole (DAPI) and visualized by fluorescence-microscopy. Cytotoxicity-testing was done with WST-1-tests (water soluble tetrazolium). No significant differences, neither with regard to Ra nor regarding SFE were determined. Adherence of S. sanguinis was less on titanium, TempBondNE and TempBond. TempBond, TempBondNE, RelyX Unicem and Implantlink Semi Classic presented low amounts of S. epidermidis. WST-testing showed high cytotoxic potential of Harvard, Aqualox, TempBondNE and TempBond. No combination of low adherent bacteria with low cytotoxicity was found. From a biological in-vitro perspective, none of the cements may be recommended for implant-supported restorations.

Evaluation of polymerization shrinkage of resin cements through in vitro and in situ experiments

NASA Astrophysics Data System (ADS)

Franco, A. P. G. O.; Karam, L. Z.; Pulido, C. A.; Gomes, O. M. M.; Kalinowski, H. J.

2014-08-01

The aim of this study was to evaluate the behavior of two types of resin cements , conventional dual and dual self adhesive, through in vitro and in situ experiments. For the in vitro assay were selected two resin cements that were handled and dispensed over a mylar strip supported by a glass plate. The Bragg grating sensors were positioned and another portion of cement. was placed, covered by another mylar strip. For the in situ experiment 16 single-rooted teeth were selected who were divided into 2 groups: group 1 - conventional dual resin cement Relyx ARC and group 2 - dual self adhesive resin cement Relyx U200 ( 3M/ESPE ). The teeth were treated and prepared to receive the intracanal posts. Two Bragg grating sensors were recorded and introduced into the root canal at different apical and coronal positions. The results showed that the in vitro experiment presented similar values of polymerization shrinkage that the in situ experiment made in cervical position; whereas Relyx ARC resulted lower values compared to Relyx U200; and cervical position showed higher shrinkage than the apical.

Effect of artificial aging and surface treatment on bond strengths to dental zirconia.

PubMed

Perdigão, J; Fernandes, S D; Pinto, A M; Oliveira, F A

2013-01-01

The objective of this project was to study the influence of artificial aging and surface treatment on the microtensile bond strengths (μTBS) between zirconia and a phosphate monomer-based self-adhesive cement. Thirty zirconia disks (IPS e.max ZirCAD, Ivoclar Vivadent) were randomly assigned to two aging regimens: AR, used as received, which served as a control, and AG, artificial aging to simulate low-temperature degradation. Subsequently, the disks of each aging regimen were assigned to three surface treatments: NT, no surface treatment; CO, surface silicatization with CoJet sand (3M ESPE); and ZP, zirconia surface treated with Z-Prime Plus (Bisco Inc). Thirty discs were made of Filtek Z250 (3M ESPE) composite resin and luted to the zirconia discs using RelyX Unicem (3M ESPE). The specimens were sectioned with a diamond blade in X and Y directions to obtain bonded beams with a cross-section of 1.0 ± 0.2 mm. The beams were tested in tensile mode in a universal testing machine at a speed of 0.5 mm/min to measure μTBS. Selected beams were selected for fractographic analysis under the SEM. Statistical analysis was carried out with two-way analysis of variance and Dunnett T3 post hoc test at a significance level of 95%. The mean μTBS for the three AR subgroups (AR-NT, AR-CO, and AR-ZP) were significantly higher than those of the corresponding AG groups (p<0.0001). Both AR-CO and AR-ZP resulted in statistically significant higher mean bond strengths than the group AR-NT (p<0.006 and p<0.0001, respectively). Both AG-CO and AG-ZP resulted in statistically significant higher mean bond strengths than the group AG-NT (both at p<0.0001). Overall, AG decreased mean μTBS. Under the SEM, mixed failures showed residual cement attached to the zirconia side of the beams. CO resulted in a characteristic roughness of the zirconia surface. AR-ZP was the only group for which the amount of residual cement occupied at least 50% of the interface in mixed failures.

Study of deformation of resin cements used in fixing of root posts through fiber Bragg grating sensors

NASA Astrophysics Data System (ADS)

Pulido, C. A.; Franco, A. P. G. O.; Karam, L. Z.; Kalinowski, H. J.; Gomes, O. M. M.

2014-05-01

The aim of the study was to evaluate the polymerization shrinkage "in situ" in resin cements inside the root canal during the fixation of glass fiber posts. For cementation teeth were randomly divided into 2 groups according to the resin cement used: Group1 - resin cement dual Relyx ARC (3M/ESPE), and Group 2 - resin cement dual Relyx U200 (3M/ESPE). Before inserting the resin cement into the root canal, two Bragg grating sensors were recorded and pasted in the region without contact with the canal, one at the apical and other at the coronal thirds of the post. The sensors measured the deformation of the resin cements in coronal and apical root thirds to obtain the values in micro-strain (μɛ).

Evaluation of tensile retention of Y-TZP crowns cemented on resin composite cores: effect of the cement and Y-TZP surface conditioning.

PubMed

Rippe, M P; Amaral, R; Oliveira, F S; Cesar, P F; Scotti, R; Valandro, L F; Bottino, M A

2015-01-01

This study evaluated the effect of the cement type (adhesive resin, self-adhesive, glass ionomer, and zinc phosphate) on the retention of crowns made of yttria-stabilized polycrystalline tetragonal zirconia (Y-TZP). Therefore, 108 freshly extracted molars were embedded in acrylic resin, perpendicular to their long axis, and prepared for full crowns: the crown preparations were removed and reconstructed using composite resin plus fiber posts with dimensions identical to the prepared dentin. The preparations were impressed using addition silicone, and Y-TZP copings were produced, which presented a special setup for the tensile testing. Cementation was performed with two adhesive resin cements (Multilink Automix, Ivoclar-Vivadent; RelyX ARC, 3M ESPE, St Paul, MN, USA), one self-adhesive resin cement (RelyX U100, 3M ESPE), one glass ionomer based cement (RelyX Luting, 3M ESPE), and one zinc phosphate cement (Cimento de Zinco, SS White, Rio de Janeiro, Brazil). For the resin cement groups, the inner surfaces of the crowns were subjected to three surface treatments: cleaning with isopropyl alcohol, tribochemical silica coating, or application of a thin low-fusing glass porcelain layer plus silanization. After 24 hours, all groups were subjected to thermocycling (6000 cycles) and included in a special device for tensile testing in a universal testing machine to test the retention of the infrastructure. After testing, the failure modes of all samples were analyzed under a stereomicroscope. The Kruskal-Wallis test showed that the surface treatment and cement type (α=0.05) affected the tensile retention results. The Multilink cement presented the highest tensile retention values, but that result was not statistically different from RelyX ARC. The surface treatment was statistically relevant only for the Multilink cement. The cement choice was shown to be more important than the crown surface treatment for cementation of a Y-TZP crown to a composite resin substrate.

Hygroscopic expansion of self-adhesive resin cements and the integrity of all-ceramic crowns.

PubMed

Kirsten, Magdalena; Matta, Ragai Edward; Belli, Renan; Lohbauer, Ulrich; Wichmann, Manfred; Petschelt, Anselm; Zorzin, José

2018-04-27

Low pH neutralization and subsequent remnant hydrophilicity can lead to hygroscopic expansion of self-adhesive resin cements (SARCs) after water storage. The aim of this in vitro study was to investigate the effects of hygroscopic expansion of SARCs, used as luting and partial core build-up material, on integrity and cement gap thickness increase of all-ceramic CAD/CAM crowns. Human third molars (n=48) were prepared and anatomical all-ceramic CAD/CAM crowns were manufactured (VITABLOCS Mark II, VITA Zahnfabrik). Crowns internal surfaces were HF etched and silanized. The prepared teeth with their respective crowns were divided into 6 groups (n=8). In groups 1, 3 and 5 the coronal dentin was removed to simulate a partial core build-up. Groups 1 and 2 were luted with iCEM (Heraeus Kulzer), 3 and 4 with RelyX Unicem 2 Automix (3M), 5 and 6 with Variolink Esthetic DC (Ivoclar Vivadent). All specimens were dual cured and stored in distilled water at 37°C. Crown integrity was controlled at baseline and in regular intervals until 180 days. Cement gap thickness was measured using an optical 3D scanner (ATOS Triple scan, GOM) at baseline and after 180 days. Crown integrity was statistically analysed using Kaplan-Meier survival analysis and cement gap thickness increase using two-way ANOVA (α=0.05). After 180 days storage, crack formation was observed in all specimens of group 1 (mean survival time of 85.5 days), in one specimen of group 2 and in two specimens of group 4. Two-way ANOVA analysis revealed a statistically significant interaction between material type and build-up on cement gap size increase for iCEM. Within the limits of this study, the application of SARCs with low pH neutralization as partial build-up material under CAD/CAM crowns is not recommended for clinical use. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

Influence of surface treatment of yttrium-stabilized tetragonal zirconium oxides and cement type on crown retention after artificial aging.

PubMed

Karimipour-Saryazdi, Mehdi; Sadid-Zadeh, Ramtin; Givan, Daniel; Burgess, John O; Ramp, Lance C; Liu, Perng-Ru

2014-05-01

Information about the influence of zirconia crown surface treatment and cement type on the retention of zirconia crowns is limited. It is unclear whether zirconia crowns require surface treatment to enhance their retention. The purpose of this in vitro study was to evaluate the effect of surface treatment on the retention of zirconia crowns cemented with 3 different adhesive resin cements after artificial aging. Ninety extracted human molars were prepared for ceramic crowns (approximately 20-degree taper, approximately 4-mm axial length) and were divided into 3 groups (n=30). Computer-aided design and computer-aided manufacturing zirconia copings were fabricated. Three surface treatments were applied to the intaglio surface of the copings. The control group received no treatment, the second group was airborne-particle abraded with 50 μm Al2O3, and the third group was treated with 30 μm silica-modified Al2O3, The copings were luted with a self-etch (RelyX Unicem 2), a total-etch (Duo-Link), or a self-etch primer (Panavia F 2.0) adhesive cement. They were stored for 24 hours at 37°C before being artificially aged with 5000 (5°C-55°C) thermal cycles and 100,000 cycles of 70 N dynamic loading. Retention was measured on a universal testing machine under tension, with a crosshead speed of 0.5 mm/min. Statistical analysis was performed with 1-way and 2-way ANOVA. Mean retention values ranged from 0.72 to 3.7 MPa. Surface treatment increased crown retention, but the difference was not statistically significant (P>.05), except for the Duo-Link cement group (P<.05). Analysis of the adhesives revealed that the Duo-Link cement resulted in significantly lower crown retention (P<.05) than the other 2 cements. For zirconia crowns, retention seems to be dependent on cement type rather than surface treatment. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Fiber post cementation strategies: effect of mechanical cycling on push-out bond strength and cement polymerization stress.

PubMed

Bergoli, Cesar Dalmolin; Amaral, Marina; Boaro, Leticia Cristina; Braga, Roberto Ruggiero; Valandro, Luiz Felipe

2012-08-01

To evaluate the effect of mechanical cycling and cementation strategies on the push-out bond strength between fiber posts and root dentin and the polymerization stresses produced using three resin cements. Eighty bovine mandibular teeth were sectioned to a length of 16 mm, prepared to 12 mm, and embedded in self-curing acrylic resin. The specimens were then distributed into 8 groups (n = 10): Gr1 - Scotchbond Multi Purpose + RelyX ARC; Gr2 - Scotchbond Multi Purpose + RelyX ARC + mechanical cycling; Gr3 - AdheSE + Multilink Automix; Gr4 - AdheSE + Multilink Automix + mechanical cycling; Gr5 - phosphoric acid + RelyX U100 (self-adhesive cement); Gr6 - phosphoric acid+ RelyX U100 + mechanical cycling; Gr7 - RelyX U100; Gr8 - RelyX U100 + mechanical cycling. The values obtained from the push-out bond strength test were submitted to two-way ANOVA and Tukey's test (p = 0.05), while the values obtained from the polymerization stress test were subjected to one-way ANOVA and Tukey's test (α = 0.05). Mechanical cycling did not affect the bond strength values (p = 0.236), while cementation strategies affected the push-out bond strength (p < 0.001). Luting with RelyX U100 and Scotch Bond Multi Purpose + RelyX ARC yielded higher push-out bond strength values. The polymerization stress results were affected by the factor "cement" (p = 0.0104): the self-adhesive cement RelyX U100 exhibited the lowest values, RelyX ARC resulted in the highest values, while Multilink Automix presented values statistically similar to the other two cements. The self-adhesive cement appears to be a good alternative for luting fiber posts due to the high push-out bond strengths and lower polymerization stress values.

Fracture Resistance of Lithium Disilicate Ceramics Bonded to Enamel or Dentin Using Different Resin Cement Types and Film Thicknesses.

PubMed

Rojpaibool, Thitithorn; Leevailoj, Chalermpol

2017-02-01

To investigate the influence of cement film thickness, cement type, and substrate (enamel or dentin) on ceramic fracture resistance. One hundred extracted human third molars were polished to obtain 50 enamel and 50 dentin specimens. The specimens were cemented to 1-mm-thick lithium disilicate ceramic plates with different cement film thicknesses (100 and 300 μm) using metal strips as spacers. The cements used were etch-and-rinse (RelyX Ultimate) and self-adhesive (RelyX U200) resin cements. Compressive load was applied on the ceramic plates using a universal testing machine, and fracture loads were recorded in Newtons (N). Statistical analysis was performed by multiple regression (p < 0.05). Representative specimens were evaluated by scanning electron microscopy to control the cement film thickness. The RelyX Ultimate group with a cement thickness of 100 μm cemented to enamel showed the highest mean fracture load (MFL; 1591 ± 172.59 N). The RelyX Ultimate groups MFLs were significantly higher than the corresponding RelyX U200 groups (p < 0.05), and thinner film cement demonstrated a higher MFL than thicker films (p < 0.05). Bonding to dentin resulted in lower MFL than with enamel (p < 0.001). Higher fracture loads were related to thinner cement film thickness and RelyX Ultimate resin cement. Bonding to dentin resulted in lower fracture loads than bonding to enamel. Reduced resin film thickness could reduce lithium disilicate restoration fracture. Etch-and-rinse resin cements are recommended for cementing on either enamel or dentin, compared with self-adhesive resin cement, for improved fracture resistance. © 2015 by the American College of Prosthodontists.

Clinical survival of indirect, anterior 3-unit surface-retained fibre-reinforced composite fixed dental prosthesis: Up to 7.5-years follow-up.

PubMed

Kumbuloglu, Ovul; Özcan, Mutlu

2015-06-01

This prospective clinical study evaluated the performance of indirect, anterior, surface-retained, fibre-reinforced-composite restorations (ISFRCR). Between June-2003 and January-2011, a total of 134 patients (83 females, 51 males, 16-68 years old) received 175 ISFRCRs (local ethical registration number: 14/9/4). All restorations were made indirectly on a plaster model using unidirectional E-glass fibres (everStick C&B, StickTech) in combination with a laboratory resin composite (Dialogue, Schütz Dental) and cemented according to the instructions of 4 resin cements [(RelyX ARC, 3M-ESPE, n=61), Bifix DC, VOCO, n=45), Variolink II (Ivoclar Vivadent, n=32) and Multilink (Ivoclar Vivadent, n=37)]. After baseline recordings, patients were followed at 6 months and thereafter annually up to 7.5 years. The evaluation protocol involved technical (chipping, debonding or fracture of tooth/restoration) and biological failures (caries). Mean observation period was 58 months. Altogether, 13 failures were observed [survival rate: 97.7%] (Kaplan-Meier). One catastrophic fracture [(cement: RelyX ARC), eight partial debonding (cement: Bifix DC (5), Multilink (1), RelyX ARC (1), Variolink II (1)] and four delaminations of veneering composite [(cement: Bifix DC (2), RelyX ARC (1), Multilink (1)] were observed. Except one replacement, all defective restorations were repaired or recemented. Annual failure rate of ISFRCRs was 1.73%. The survival rates with the four resin cements did not show significant differences (RelyX ARC: 98.3%; Bifix DC: 93.5%; Variolink 2: 100%; Multilink: 100%) (p=0.114). Secondary caries did not occur in any of the teeth. The 3-unit anterior indirect surface-retained resin-bonded FRC FDPs showed similar clinical survival rate when cemented with the resin cements tested. Experienced failures in general were due to debonding of the restoration or delamination of the veneering composite. 3-unit surface retained resin-bonded FRC FDPs could be considered minimal invasive and cost-effective alternatives to conventional tooth- or implant-borne FDPs. Failures were mainly repairable in the form of chipping or debonding depending on the resin cement type. Copyright © 2015 Elsevier Ltd. All rights reserved.

Light curing through glass ceramics with a second- and a third-generation LED curing unit: effect of curing mode on the degree of conversion of dual-curing resin cements.

PubMed

Flury, Simon; Lussi, Adrian; Hickel, Reinhard; Ilie, Nicoleta

2013-12-01

The aim of this study was to measure the degree of conversion (DC) of five dual-curing resin cements after different curing modes with a second- and a third-generation light-emitting diode (LED) curing unit. Additionally, irradiance of both light curing units was measured at increasing distances and through discs of two glass ceramics for computer-aided design/manufacturing (CAD/CAM). Irradiance and spectra of the Elipar FreeLight 2 (Standard Mode (SM)) and of the VALO light curing unit (High Power Mode (HPM) and Xtra Power Mode (XPM)) were measured with a MARC radiometer. Irradiance was measured at increasing distances (control) and through discs (1.5 to 6 mm thickness) of IPS Empress CAD and IPS e.max CAD. DC of Panavia F2.0, RelyX Unicem 2 Automix, SpeedCEM, BisCem, and BeautiCem SA was measured with an attenuated total reflectance-Fourier transform infrared spectrometer when self-cured (negative control) or light cured in SM for 40 s, HPM for 32 s, or XPM for 18 s. Light curing was performed directly (positive control) or through discs of either 1.5- or 3-mm thickness of IPS Empress CAD or IPS e.max CAD. DC was analysed with Kruskal-Wallis tests followed by pairwise Wilcoxon rank sum tests (α = 0.05). Maximum irradiances were 1,545 mW/cm(2) (SM), 2,179 mW/cm(2) (HPM), and 4,156 mW/cm(2) (XPM), and all irradiances decreased by >80 % through discs of 1.5 mm, ≥95 % through 3 mm, and up to >99 % through 6 mm. Generally, self-curing resulted in the lowest DC. For some cements, direct light curing did not result in higher DC compared to when light cured through ceramic discs. For other cements, light curing through ceramic discs of 3 mm generally reduced DC. Light curing was favourable for dual-curing cements. Some cements were more susceptible to variations in curing mode than others. When light curing a given cement, the higher irradiances of the third-generation LED curing unit resulted in similar DC compared to the second-generation one, though at shorter light curing times.

Tensile bond strength of indirect composites luted with three new self-adhesive resin cements to dentin.

PubMed

Türkmen, Cafer; Durkan, Meral; Cimilli, Hale; Öksüz, Mustafa

2011-08-01

The aims of this study were to evaluate the tensile bond strengths between indirect composites and dentin of 3 recently developed self-adhesive resin cements and to determine mode of failure by SEM. Exposed dentin surfaces of 70 mandibular third molars were used. Teeth were randomly divided into 7 groups: Group 1 (control group): direct composite resin restoration (Alert) with etch-and-rinse adhesive system (Bond 1 primer/adhesive), Group 2: indirect composite restoration (Estenia) luted with a resin cement (Cement-It) combined with the same etch-and-rinse adhesive, Group 3: direct composite resin restoration with self-etch adhesive system (Nano-Bond), Group 4: indirect composite restoration luted with the resin cement combined with the same self-etch adhesive, Groups 5-7: indirect composite restoration luted with self-adhesive resin cements (RelyX Unicem, Maxcem, and Embrace WetBond, respectively) onto the non-pretreated dentin surfaces. Tensile bond strengths of groups were tested with a universal testing machine at a constant speed of 1 mm/min using a 50 kgf load cell. Results were statistically analyzed by the Student's t-test. The failure modes of all groups were also evaluated. The indirect composite restorations luted with the self-adhesive resin cements (groups 5-7) showed better results compared to the other groups (p<0.05). Group 4 showed the weakest bond strength (p>0.05). The surfaces of all debonded specimens showed evidence of both adhesive and cohesive failure. The new universal self-adhesive resins may be considered an alternative for luting indirect composite restorations onto non-pretreated dentin surfaces.

First clinical experiences with CAD/CAM-fabricated PMMA-based fixed dental prostheses as long-term temporaries.

PubMed

Huettig, Fabian; Prutscher, Andreas; Goldammer, Christoph; Kreutzer, Curt A; Weber, Heiner

2016-01-01

The clinical performance of polymethylmethacrylate (PMMA)-based fixed dental prostheses (FDP) was evaluated in the indication of long-term temporaries. In the current indication of the applied machinable PMMA-based material (Vita CAD-Temp), i.e. temporary crowns and FDPs, 27 patients with compromised dentitions (uncertain dental prognosis or postponement of a removable treatment option) were recruited and 45 FDPs (3 or 4 units, 37 terminal-retained, 8 cantilevered) were inserted. Frameworks were computer-aided design (CAD)/computer-aided manufacturing (CAM)-manufactured after conventional impression taking and labside scanning of stone master casts. A resin-modified hybrid cement material (RelyX Unicem) was used for luting in a conventional protocol. Clinical follow-up was performed biannually. Over an observation time from 2 to 26 months (median 13 months), 11 complications were found in 9 out of 45 PMMA restorations: 4 losses of retention, 5 complete fractures; two of these subsequent to a trepanation for endodontic treatment. Thereby, 3 out of 8 cantilevered FDPs had to be removed within 8 months. Thus, the statistical evaluation included FDPs with abutment at end, only. These standard design FDPs (n = 37) showed a 90.4 % survival rate with a complication-free rate of 88.3 % estimated for an observation time of 16 months. Cantilevered FDPs and reconstructions on abutment teeth with markedly reduced biological prognosis or endodontic intervention yielded a high-failure rate. Terminal-retained FDPs performed clinically well in cases without compromised abutment teeth. PMMA-based material might be used successfully for long-term temporization with 3- to 4-unit FDPs in a standard design over at least one year.

Biomechanical Effect of Ferrule on Incisors Restored with a Fiberglass Post and Lithium-Disilicate Ceramic Crown after Thermal Cycling and Fatigue Loading.

PubMed

Valdivia, Andréa Dolores Correia Miranda; Rodrigues, Monise de Paula; Bicalho, Aline Aredes; Van Meerbeek, Bart; Sloten, Jos Vander; Pessoa, Roberto Sales E; Soares, Carlos José

2018-04-19

To evaluate the biomechanics of endodontically treated incisors restored with a fiberglass post and a CAD/CAM lithium-disilicate ceramic crown with/without a ferrule after thermal and mechanical aging. Twenty bovine incisors were divided into two groups (n = 10): 1. Fe, with a ferrule of 2 mm, and 2. NFe, without a ferrule. After endodontic treatment, the teeth were restored using a fiberglass post (Exacto 3, Angelus) and composite core (Tetric Ceram, Ivoclar Vivadent). They then received a CAD/CAM lithium-disilicate ceramic crown (IPS e.max CAD) luted using a self-adhesive composite (RelyX Unicem 2, 3M Oral Care). All specimens were subjected to 20,000 thermocycles and 2,400,000 simulated chewing cycles. Ceramic crown and root dentin strains (μS) were measured using strain gauges (n = 10) during 100-N loading before and after the thermal and mechanical aging, and upon fracture loading. The specimens were subsequently loaded to fracture (N). The stress distribution was analyzed using 3D individualized finite-element models created by micro-CT of experimental samples (n = 3). Strain data were analyzed using two-way ANOVA and Tukey's HSD test. Fracture resistance was analyzed using Student's t-test and fracture mode was analyzed using the chi-squared test (α = 0.05). After aging, NFe exhibited significantly higher root dentin deformation (buccal: 1248.0 ± 282.8; lingual: 516.2 ± 195.0; p < 0.001) than Fe (buccal, 554.0 ± 233.8; lingual: 311.8 ± 159.0; p < 0.001). The deformation measured on ceramic crowns was not influenced by ferrule presence or aging process. Significantly higher fracture resistance (N) was observed for the Fe (1099.6 ± 214.8) than the NFe group (675.3 ± 113.8) (p < 0.001). The NFe group revealed a lower fracture resistance:root strain ratio than did the Fe group. The stress levels on root dentin and fiberglass were lower for the Fe group. The NFe group showed increased root dentin strain after the aging process. The Fe group revealed higher fracture resistance, lower stress concentration on root dentin and fewer catastrophic fractures.

Effect of two fiber post types and two luting cement systems on regional post retention using the push-out test.

PubMed

Wang, Vivian J-J; Chen, Ya-Ming; Yip, Kevin H-K; Smales, Roger J; Meng, Qing-Fei; Chen, Lijuan

2008-03-01

To investigate regional root canal push-out bond strengths for two fiber-reinforced post types using two adhesive systems. The crowns of 24 recently extracted sound maxillary central incisors were sectioned transversely 2 mm coronal to the labial cemento-enamel junction, and the roots treated endodontically. Following standardized post space preparations, fiber-reinforced posts (C-POST; AESTHETI-PLUS) were placed using two adhesive systems (acid-etch ONE-STEP PLUS/C&B CEMENT; self-adhesive RelyX Unicem), in four equal groups. Push-out bond strength tests were performed at four sites in each root. Results were analyzed using split-plot ANOVA, with a=0.05 for statistical significance. AESTHETI-PLUS quartz fiber-reinforced posts showed significantly higher push-out strengths than C-POST carbon fiber-reinforced posts (P<0.0001). The separate acid-etch adhesive system resulted in significantly higher bond strengths than the self-etch self-adhesive system (P<0.0001). Bond strengths decreased significantly from coronal to apical root canal regions (P<0.0001). The quartz fiber-reinforced post placed using the separate acid-etch adhesive system provided significantly better post retention than the carbon fiber-reinforced post placed using the self-etch self-adhesive system.

Fracture Resistance of Ceramic Laminate Veneers Bonded to Teeth with Class V Composite Fillings after Cyclic Loading.

PubMed

Sadighpour, Leyla; Geramipanah, Farideh; Rasaei, Vanya; Kharazi Fard, Mohammad J

2018-01-01

Porcelain laminate veneers (PLVs) are sometimes required to be used for teeth with composite fillings. This study examined the fracture strength of PLVs bonded to the teeth restored with different sizes of class V composite fillings. Thirty-six maxillary central incisors were divided into three groups ( n =12): intact teeth (control) and teeth with class V composite fillings of one-third or two-thirds of the crown height (small or large group, resp.). PLVs were made by using IPS e.max and bonded with a resin cement (RelyX Unicem). Fracture resistance ( N ) was measured after cyclic loading (1 × 10 6 cycles, 1.2 Hz). For statistical analyses, one-way ANOVA and Tukey test were used ( α =0.05). There was a significant difference between the mean failure loads of the test groups ( P =0.004), with the Tukey-HSD test showing lower failure loads in the large-composite group compared to the control ( P =0.02) or small group ( P =0.05). The control and small-composite groups achieved comparable results ( P > 0.05). Failure loads of PLVs bonded to intact teeth and to teeth with small class V composite fillings were not significantly different. However, extensive composite fillings could compromise the bonding of PLVs.

Effect of Resin-modified Glass Ionomer Cement Dispensing/Mixing Methods on Mechanical Properties.

PubMed

Sulaiman, T A; Abdulmajeed, A A; Altitinchi, A; Ahmed, S N; Donovan, T E

2018-03-23

Resin-modified glass ionomer cements (RMGIs) are often used for luting indirect restorations. Hand-mixing traditional cements demands significant time and may be technique sensitive. Efforts have been made by manufacturers to introduce the same cement using different dispensing/mixing methods. It is not known what effects these changes may have on the mechanical properties of the dental cement. The purpose of this study was to evaluate the mechanical properties (diametral tensile strength [DTS], compressive strength [CS], and fracture toughness [FT]) of RMGIs with different dispensing/mixing systems. The RMGI specimens (n=14)-RelyX Luting (hand mix), RelyX Luting Plus (clicker-hand mix), RelyX Luting Plus (automix) (3M ESPE), GC Fuji PLUS (capsule-automix), and GC FujiCEM 2 (automix) (GC)-were prepared for each mechanical test and examined after thermocycling (n=7/subgroup) for 20,000 cycles to the following: DTS, CS (ISO 9917-1) and FT (ISO standard 6872; Single-edge V-notched beam method). Specimens were mounted and loaded with a universal testing machine until failure occurred. Two-/one-way analysis of variance followed by Tukey honestly significantly different post hoc test was used to analyze data for statistical significance ( p<0.05). The interaction effect of both dispensing/mixing method and thermocycling was significant only for the CS test of the GC group ( p<0.05). The different dispensing/mixing methods had no effect on the DTS of the tested cements. The CS of GC Fuji PLUS was significantly higher than that of the automix version ( p<0.05). The FT decreased significantly when switching from RelyX (hand mix) to RelyX Luting Plus (clicker-hand mix) and to RelyX Luting Plus (automix) ( p<0.05). Except in the case of the DTS of the GC group and the CS of GC Fuji PLUS, thermocycling had a significant effect reducing the mechanical properties of the RMGI cements ( p<0.05). Introducing alternative dispensing/mixing methods for mixing RMGIs to reduce time and technique sensitivity may affect mechanical properties and is brand dependent.

Universal cements: dual activated and chemically activated

PubMed Central

de Lima, Eliane; Santos, Ricardo; Durão, Márcia; Nascimento, Armiliana; Braz, Rodivan

2016-01-01

Abstract Objective: The aim of the present study was to assess the bond strength of universal cements cured either dually or chemically only. Methods: Three cements were assessed using different types of application: dual activated (DA) or chemically activated (CA). In total 80 dentin blocks were used, obtained through the enamel wear of the lingual and buccal surfaces of bovine incisors. Standard cone-shaped cavity preparations were created using diamond burs. Subsequently, indirect restoration blocks were designed with Filtek Z350 (3M ESPE) composite resin. The teeth were divided into two groups (DA and CA) and then subdivided into four subgroups (n = 10) prior to cementation with the respective products: Duo-Link (Bisco); RelyX Ultimate (3M ESPE); Nexus 3 (Kerr) and conventional RelyX ARC (3M ESPE) as the control. The cementation in the PA group was applied following the manufacturer’s instructions. The CA group was cemented in a darkroom to avoid exposure to light. They were stored in distilled water at 37 °C for 24 h and submitted to the push-out test. Data were analyzed by two-way ANOVA and Tukey’s post-hoc test (p < .05). Results: The greatest bond strength results were obtained for photoactivated universal cements. Conclusion: Chemical activation is not sufficient to ensure acceptable bond strength. PMID:28642922

Light transmittance of zirconia as a function of thickness and microhardness of resin cements under different thicknesses of zirconia

PubMed Central

Egilmez, Ferhan; Ergun, Gulfem; Kaya, Bekir M.

2013-01-01

Objective: The objective of this study was to compare microhardness of resin cements under different thicknesses of zirconia and the light transmittance of zirconia as a function of thickness. Study design: A total of 126 disc-shaped specimens (2 mm in height and 5 mm in diameter) were prepared from dual-cured resin cements (RelyX Unicem, Panavia F and Clearfil SA cement). Photoactivation was performed by using quartz tungsten halogen and light emitting diode light curing units under different thicknesses of zirconia. Then the specimens (n=7/per group) were stored in dry conditions in total dark at 37°C for 24 h. The Vicker’s hardness test was performed on the resin cement layer with a microhardness tester. Statistical significance was determined using multifactorial analysis of variance (ANOVA) (alpha=.05). Light transmittance of different thicknesses of zirconia (0.3, 0.5 and 0.8 mm) was measured using a hand-held radiometer (Demetron, Kerr). Data were analyzed using one-way ANOVA test (alpha=.05). Results: ANOVA revealed that resin cement and light curing unit had significant effects on microhardness (p < 0.001). Additionally, greater zirconia thickness resulted in lower transmittance. There was no correlation between the amount of light transmitted and microhardness of dual-cured resin cements (r = 0.073, p = 0.295). Conclusion: Although different zirconia thicknesses might result in insufficient light transmission, dual-cured resin cements under zirconia restorations could have adequate microhardness. Key words:Zirconia, microhardness, light transmittance, resin cement. PMID:23385497

Effect of smear layer thickness and pH of self-adhesive resin cements on the shear bond strength to dentin.

PubMed

Ebrahimi Chaharom, Mohammad Esmaeel; Ajami, Amir Ahmad; Bahari, Mahmoud; Rezazadeh, Haleh

2017-01-01

There are concerns in relation to the bonding efficacy of self-adhesive resin cements to dentin covered with the smear layer. This study aims to evaluate the effect of smear layer thickness and different pH values of self-adhesive resin cements on the shear bond strength to dentin. The dentin on the buccal and lingual surfaces of 48 sound human premolars were abraded with 60- and 600-grit silicon carbide papers to achieve thick and thin smear layers, respectively. The samples were divided into three groups (n = 16) based on the cement pH: Rely-X Unicem (RXU) (pH < 2); Clearfil SA Luting (CSL) (pH = 3); and Speed CEM (SPC) (pH = 4.5). In each group, composite resin blocks were bonded to the buccal and lingual surfaces. After 24 h, the shear bond strength values were measured in MPa, and the failure modes were evaluated under a stereomicroscope. Data were analyzed with two-way ANOVA and post hoc least significant difference tests (P < 0.05). Cement pH had a significant effect on the shear bond strength (P = 0.02); however, the smear layer thickness had no significant effect on the shear bond strength (P > 0.05). The cumulative effect of these variables was not significant, either (P = 0.11). The shear bond strengths of SPC and CSL self-adhesive resin cements were similar and significantly lower than that of RXU. The smear layer thickness was not a determining factor for the shear bond strength value of self-adhesive resin cements.

Misfit and microleakage of implant-supported crown copings obtained by laser sintering and casting techniques, luted with glass-ionomer, resin cements and acrylic/urethane-based agents.

PubMed

Castillo-Oyagüe, Raquel; Lynch, Christopher D; Turrión, Andrés S; López-Lozano, José F; Torres-Lagares, Daniel; Suárez-García, María-Jesús

2013-01-01

This study evaluated the marginal misfit and microleakage of cement-retained implant-supported crown copings. Single crown structures were constructed with: (1) laser-sintered Co-Cr (LS); (2) vacuum-cast Co-Cr (CC) and (3) vacuum-cast Ni-Cr-Ti (CN). Samples of each alloy group were randomly luted in standard fashion onto machined titanium abutments using: (1) GC Fuji PLUS (FP); (2) Clearfil Esthetic Cement (CEC); (3) RelyX Unicem 2 Automix (RXU) and (4) DentoTemp (DT) (n=15 each). After 60 days of water ageing, vertical discrepancy was SEM-measured and cement microleakage was scored using a digital microscope. Misfit data were subjected to two-way ANOVA and Student-Newman-Keuls multiple comparisons tests. Kruskal-Wallis and Dunn's tests were run for microleakage analysis (α=0.05). Regardless of the cement type, LS samples exhibited the best fit, whilst CC and CN performed equally well. Despite the framework alloy and manufacturing technique, FP and DT provide comparably better fit and greater microleakage scores than did CEC and RXU, which showed no differences. DMLS of Co-Cr may be a reliable alternative to the casting of base metal alloys to obtain well-fitted implant-supported crowns, although all the groups tested were within the clinically acceptable range of vertical discrepancy. No strong correlations were found between misfit and microleakage. Notwithstanding the framework alloy, definitive resin-modified glass-ionomer (FP) and temporary acrylic/urethane-based (DT) cements demonstrated comparably better marginal fit and greater microleakage scores than did 10-methacryloxydecyl-dihydrogen phosphate-based (CEC) and self-adhesive (RXU) dual-cure resin agents. Copyright © 2012 Elsevier Ltd. All rights reserved.

Extrusion shear strength between an alumina-based ceramic and three different cements.

PubMed

Borges, Gilberto Antonio; de Goes, Mario Fernando; Platt, Jeffrey A; Moore, Keith; de Menezes, Fernando Hueb; Vedovato, Euripedes

2007-09-01

Surface treatment is an essential step in bonding a ceramic to resin. Alumina ceramics are particularly difficult to prepare for adequate bonding to composite resin cements. The purpose of this study was to evaluate the bond strength between a densely sintered alumina ceramic and bovine dentin with 2 adhesive resin cements and a resin-modified glass ionomer cement using an extrusion shear strength test. Alumina cones (n=30), 4 mm in height, 3 mm in diameter at the small end, and with an 8-degree taper, were fabricated. Without any treatment, the cones were cemented in a standardized cavity in 2.5-mm-thick bovine dentin discs using 1 of 3 cement systems: Panavia F, RelyX ARC, or RelyX Luting. The cements were manipulated following the manufacturers' instructions. After 24 hours of storage at 37 degrees C, an extrusion shear test was performed in a universal testing machine at 0.5 mm/min until bonding failure. The data were analyzed using 1-way ANOVA and Tukey HSD test (alpha=.05). All fractured specimens were examined at x25 magnification and classified by fracture mode. Representative specimens were selected for SEM observation. The highest strength values were obtained with Panavia F, and they were significantly higher (P<.05) than each of the other 2 cements, which were not significantly different from each other. Panavia F resulted in predominantly mixed failure and RelyX ARC and RelyX Vitremer showed primarily adhesive failure. An MDP-containing adhesive system (Panavia F) provides better extrusion bond strength to a high-density alumina ceramic than a Bis-GMA resin luting agent system (RelyX ARC) or a resin-modified glass ionomer cement system (RelyX Luting).

Fracture Resistance of Ceramic Laminate Veneers Bonded to Teeth with Class V Composite Fillings after Cyclic Loading

PubMed Central

Rasaei, Vanya; Kharazi Fard, Mohammad J.

2018-01-01

Purpose Porcelain laminate veneers (PLVs) are sometimes required to be used for teeth with composite fillings. This study examined the fracture strength of PLVs bonded to the teeth restored with different sizes of class V composite fillings. Materials and Methods Thirty-six maxillary central incisors were divided into three groups (n=12): intact teeth (control) and teeth with class V composite fillings of one-third or two-thirds of the crown height (small or large group, resp.). PLVs were made by using IPS e.max and bonded with a resin cement (RelyX Unicem). Fracture resistance (N) was measured after cyclic loading (1 × 106 cycles, 1.2 Hz). For statistical analyses, one-way ANOVA and Tukey test were used (α=0.05). Results There was a significant difference between the mean failure loads of the test groups (P=0.004), with the Tukey-HSD test showing lower failure loads in the large-composite group compared to the control (P=0.02) or small group (P=0.05). The control and small-composite groups achieved comparable results (P > 0.05). Conclusions Failure loads of PLVs bonded to intact teeth and to teeth with small class V composite fillings were not significantly different. However, extensive composite fillings could compromise the bonding of PLVs. PMID:29849632

The effect of nano-structured alumina coating on resin-bond strength to zirconia ceramics.

PubMed

Jevnikar, Peter; Krnel, Kristoffer; Kocjan, Andraz; Funduk, Nenad; Kosmac, Tomaz

2010-07-01

The aim of this study was to functionalize the surface of yttria partially stabilized tetragonal zirconia ceramics (Y-TZP) with a nano-structured alumina coating to improve resin bonding. A total of 120 densely sintered disc-shaped specimens (15.5+/-0.03 mm in diameter and 2.6+/-0.03 mm thick) were produced from biomedical-grade TZ-3YB-E zirconia powder (Tosoh, Tokyo, Japan), randomly divided into three groups of 40 and subjected to the following surface treatments: AS - as-sintered; APA - airborne-particle abraded; POL - polished. Half of the discs in each group received an alumina coating that was fabricated by exploiting the hydrolysis of aluminium nitride (AlN) powder (groups AS-C, APA-C, POL-C). The coating was characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The shear-bond strength of the self-etching composite resin (RelyX Unicem, 3M ESPE, USA) was then studied for the coated and uncoated surfaces of the as-sintered, polished and airborne-particle abraded specimens before and after thermocycling (TC). The SEM/TEM analyses revealed that the application of an alumina coating to Y-TZP ceramics created a highly retentive surface for resin penetration. The coating showed good surface coverage and a uniform thickness of 240 nm. The resin-bond strength to the groups AS-C, APA-C, POL-C was significantly higher than to the groups AS, APA and POL, both before and after TC (p< or =0.05). During TC all the specimens in the POL and AS groups debonded spontaneously. In contrast, the TC did not affect the bond strength of the AS-C, POL-C and APA-C groups. A non-invasive method has been developed that significantly improves resin-bond strength to Y-TZP ceramics. After surface functionalization the bond survives thermocycling without reduction in strength. The method is relatively simple and has the potential to become an effective conditioning method for zirconia ceramics. Copyright 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Influence of fluorescent dye on physical-mechanical properties of luting cements for confocal microscopy analysis.

PubMed

Oliveira, Dayane; Prieto, Lúcia; Araújo, Cíntia; Coppini, Erick; Pereira, Gisele; Paulillo, Luís

2014-12-01

To evaluate the influence of a fluorescent dye (rhodamine B) on the physical and mechanical properties of three different luting cements: a conventional adhesive luting cement (RelyX ARC, 3M/ESPE), a self-adhesive luting cement (RelyX U-200, 3M/ESPE), and a self-etching and self-adhesive luting cement (SeT PP, SDI). The cements were mixed with 0.03 wt% rhodamine B, formed into bar-shaped specimens (n = 10), and light cured using an LED curing unit (Radii, SDI) with a radiant exposure of 32 J/cm(2) . The Knoop hardness (KHN), flexural strength (FS), and Young's modulus (YM) analyses were evaluated after storage for 24 h. Outcomes were subjected to two-way ANOVA and Tukey's test (P = 0.05) for multiple comparisons. No significant differences in FS or YM were observed among the tested groups (P ≥ 0.05); the addition of rhodamine B increased the hardness of the luting cements tested. The addition of a fluorescent agent at 0.03 wt% concentration does not negatively affect the physical-mechanical properties of the luting cement polymerization behavior. © 2014 Wiley Periodicals, Inc.

A descriptive study of the radiographic density of implant restorative cements.

PubMed

Wadhwani, Chandur; Hess, Timothy; Faber, Thomas; Piñeyro, Alfonso; Chen, Curtis S K

2010-05-01

Cementation of implant prostheses is a common practice. Excess cement in the gingival sulcus may harm the periodontal tissues. Identification of the excess cement may be possible with the use of radiographs if the cement has sufficient radiopacity. The purpose of this study was to compare the radiographic density of different cements used for implant prostheses. Eight different cements were compared: TempBond Original (TBO), TempBond NE (TBN), Fleck's (FL), Dycal (DY), RelyX Unicem (RXU), RelyX Luting (RXL), Improv (IM), and Premier Implant Cement (PIC). Specimen disks, 2 mm in thickness, were radiographed. Images were made using photostimulable phosphor (PSP) plates with standardized exposure values. The average grey level of the central area of each specimen disk was selected and measured in pixels using a software analysis program, ImageTool, providing an average grey level value representative of radiodensity for each of the 8 cements. The radiodensity was determined using the grey level values of the test materials, which were recorded and compared to a standard aluminum step wedge. An equivalent thickness of aluminum in millimeters was calculated using best straight line fit estimates. To assess contrast effects by varying the exposure settings, a second experiment using 1-mm-thick cement specimens radiographed at both 60 kVp and 70 kVp was conducted. The PSP plates with specimens were measured for a grey level value comparison to the standard aluminum step wedge, using the same software program. The highest grey level values were recorded for the zinc cements (TBO, TBN, and FL), with the 1-mm specimen detectable at both 60- and 70-kVp settings. A lower grey level was recorded for DY, indicative of a lower radiodensity compared to the zinc cements, but higher than RXL and RXU. The implant-specific cements had the lowest grey level values. IM could only be detected in 2-mm-thick sections with a lower aluminum equivalence value than the previously mentioned cements. PIC could not be detected radiographically for either the 1-mm or 2-mm thicknesses at either of the kVp settings. Some types of cement commonly used for the cementation of implant-supported prostheses have poor radiodensity and may not be detectable following radiographic examination.

Fracture Strength of Monolithic All-Ceramic Crowns on Titanium Implant Abutments.

PubMed

Weyhrauch, Michael; Igiel, Christopher; Scheller, Herbert; Weibrich, Gernot; Lehmann, Karl Martin

2016-01-01

The fracture strengths of all-ceramic crowns cemented on titanium implant abutments may vary depending on crown materials and luting agents. The purpose of this study was to examine differences in fracture strength among crowns cemented on implant abutments using crowns made of seven different monolithic ceramic materials and five different luting agents. In total, 525 crowns (75 each of Vita Mark II, feldspathic ceramic [FSC]; Ivoclar Empress CAD, leucite-reinforced glass ceramic [LrGC]; Ivoclar e.max CAD, lithium disilicate [LiDS]; Vita Suprinity, presintered zirconia-reinforced lithium silicate ceramic [PSZirLS]; Vita Enamic, polymer-reinforced fine-structure feldspathic ceramic [PolyFSP], Lava Ultimate; resin nanoceramic [ResNC], Celtra Duo; fully crystallized zirconia-reinforced lithium silicate [FcZirLS]) were milled using a CAD/CAM system. The inner surfaces of the crowns were etched and silanized. Titanium implant abutments were fixed on implant analogs, and airborne-particle abrasion was used on their exterior specific adhesion surfaces (Al2O3, 50 μm). Then, the abutments were degreased and silanized. The crowns were cemented on the implant abutments using five luting agents (Multilink Implant, Variolink II, RelyX Unicem, GC FujiCEM, Panavia 2.0). After thermocycling for 5,000 cycles (5 to 55°C, 30 seconds dwell time), the crowns were subjected to fracture strength testing under static load using a universal testing machine. Statistical analyses were performed using analysis of variance (α = .0002) and the Bonferroni correction. No significant difference among the luting agents was found using the different all-ceramic materials. Ceramic materials LiDS, PSZirLS, PolyFSP, and ResNC showed significantly higher fracture strength values compared with FSC, FcZirLS, and LrGC. The PSZirLS especially showed significantly better results. Within the limitations of this study, fracture strength was not differentially affected by the various luting agents. However, the fracture strength was significantly higher for PSZirLS, PolyFSP, ResNC, and LiDS ceramics than for the FSP, LrGC, and the FcZirLS ceramic with all luting agents tested.

Influence of Temporary Cements on the Bond Strength of Self-Adhesive Cement to the Metal Coronal Substrate.

PubMed

Peixoto, Raniel Fernandes; De Aguiar, Caio Rocha; Jacob, Eduardo Santana; Macedo, Ana Paula; De Mattos, Maria da Gloria Chiarello; Antunes, Rossana Pereira de Almeida

2015-01-01

This research evaluated the influence of temporary cements (eugenol-containing [EC] or eugenol-free [EF]) on the tensile strength of Ni-Cr copings fixed with self-adhesive resin cement to the metal coronal substrate. Thirty-six temporary crowns were divided into 4 groups (n=9) according to the temporary cements: Provy, Dentsply (eugenol-containing), Temp Cem, Vigodent (eugenol-containing), RelyX Temp NE, 3M ESPE (eugenol-free) and Temp Bond NE, Kerr Corp (eugenol-free). After 24 h of temporary cementation, tensile strength tests were performed in a universal testing machine at a crosshead speed of 0.5 mm/min and 1 kN (100 kgf) load cell. Afterwards, the cast metal cores were cleaned by scraping with curettes and air jet. Thirty-six Ni-Cr copings were cemented to the cast metal cores with self-adhesive resin cement (RelyX U200, 3M ESPE). Tensile strength tests were performed again. In the temporary cementation, Temp Bond NE (12.91 ± 2.54) and Temp Cem (12.22 ± 2.96) presented the highest values of tensile strength and were statistically similar to each other (p>0.05). Statistically significant difference (p<0.05) was observed only between Provy (164.44 ± 31.23) and Temp Bond NE (88.48 ± 21.83) after cementation of Ni-Cr copings with self-adhesive resin cement. In addition, Temp Cem (120.68 ± 48.27) and RelyX Temp NE (103.04 ± 26.09) showed intermediate tensile strength values. In conclusion, the Provy eugenol-containing temporary cement was associated with the highest bond strength among the resin cements when Ni-Cr copings were cemented to cast metal cores. However, the eugenol cannot be considered a determining factor in increased bond strength, since the other tested cements (1 eugenol-containing and 2 eugenol-free) were similar.

Vertical misfit of laser-sintered and vacuum-cast implant-supported crown copings luted with definitive and temporary luting agents.

PubMed

Castillo-de-Oyagüe, Raquel; Sánchez-Turrión, Andrés; López-Lozano, José-Francisco; Albaladejo, Alberto; Torres-Lagares, Daniel; Montero, Javier; Suárez-García, Maria-Jesús

2012-07-01

This study aimed to evaluate the vertical discrepancy of implant-supported crown structures constructed with vacuum-casting and Direct Metal Laser Sintering (DMLS) technologies, and luted with different cement types. Crown copings were fabricated using: (1) direct metal laser sintered Co-Cr (LS); (2) vacuum-cast Co-Cr (CC); and (3) vacuum-cast Ti (CT). Frameworks were luted onto machined implant abutments under constant seating pressure. Each alloy group was randomly divided into 5 subgroups (n = 10 each) according to the cement system utilized: Subgroup 1 (KC) used resin-modified glass-ionomer Ketac Cem Plus; Subgroup 2 (PF) used Panavia F 2.0 dual-cure resin cement; Subgroup 3 (RXU) used RelyX Unicem 2 Automix self-adhesive dual-cure resin cement; Subgroup 4 (PIC) used acrylic/urethane-based temporary Premier Implant Cement; and Subgroup 5 (DT) used acrylic/urethane-based temporary DentoTemp cement. Vertical misfit was measured by scanning electron microscopy (SEM). Two-way ANOVA and Student-Newman-Keuls tests were run to investigate the effect of alloy/fabrication technique, and cement type on vertical misfit. The statistical significance was set at α = 0.05. The alloy/manufacturing technique and the luting cement affected the vertical discrepancy (p < 0.001). For each cement type, LS samples exhibited the best fit (p < 0.01) whereas CC and CT frames were statistically similar. Within each alloy group, PF and RXU provided comparably greater discrepancies than KC, PIC, and DT, which showed no differences. Laser sintering may be an alternative to vacuum-casting of base metals to obtain passive-fitting implant-supported crown copings. The best marginal adaptation corresponded to laser sintered structures luted with glass-ionomer KC, or temporary PIC or DT cements. The highest discrepancies were recorded for Co-Cr and Ti cast frameworks bonded with PF or RXU resinous agents. All groups were within the clinically acceptable misfit range.

Assessing degradation of composite resin cements during artificial aging by Martens hardness.

PubMed

Bürgin, Stefan; Rohr, Nadja; Fischer, Jens

2017-05-19

Aim of the study was to verify the efficiency of Martens hardness measurements in detecting the degradation of composite resin cements during artificial aging. Four cements were used: Variolink II (VL2), RelyX Unicem 2 Automix (RUN), PermaFlo DC (PDC), and DuoCem (DCM). Specimens for Martens hardness measurements were light-cured and stored in water at 37 °C for 1 day to allow complete polymerization (baseline). Subsequently the specimens were artificially aged by water storage at 37 °C or thermal cycling (n = 6). Hardness was measured at baseline as well as after 1, 4, 9 and 16 days of aging. Specimens for indirect tensile strength measurements were produced in a similar manner. Indirect tensile strength was measured at baseline and after 16 days of aging (n = 10). The results were statistically analyzed using one-way ANOVA (α = 0.05). After water storage for 16 days hardness was significantly reduced for VL2, RUN and DCM while hardness of PDC as well as indirect tensile strength of all cements were not significantly affected. Thermal cycling significantly reduced both, hardness and indirect tensile strength for all cements. No general correlation was found between Martens hardness and indirect tensile strength. However, when each material was analyzed separately, relative change of hardness and of indirect tensile strength revealed a strong linear correlation. Martens hardness is a sensible test method to assess aging of resin composite cements during thermal cycling that is easy to perform.

Push-out bond strengths of fiber-reinforced composite posts with various resin cements according to the root level

PubMed Central

Chang, Hoon-Sang; Noh, Young-Sin; Lee, Yoon; Min, Kyung-San

2013-01-01

PURPOSE The aim of this study was to determine whether the push-out bond strengths between the radicular dentin and fiber reinforced-composite (FRC) posts with various resin cements decreased or not, according to the coronal, middle or apical level of the root. MATERIALS AND METHODS FRC posts were cemented with one of five resin cement groups (RelyX Unicem: Uni, Contax with activator & LuxaCore-Dual: LuA, Contax & LuxaCore-Dual: Lu, Panavia F 2.0: PA, Super-Bond C&B: SB) into extracted human mandibular premolars. The roots were sliced into discs at the coronal, middle and apical levels. Push-out bond strength tests were performed with a universal testing machine at a crosshead speed of 0.5 mm/min, and the failure aspect was analyzed. RESULTS There were no significant differences (P>.05) in the bond strengths of the different resin cements at the coronal level, but there were significant differences in the bond strengths at the middle and apical levels (P<.05). Only the Uni and LuA cements did not show any significant decrease in their bond strengths at all the root levels (P>.05); all other groups had a significant decrease in bond strength at the middle or apical level (P<.05). The failure aspect was dominantly cohesive at the coronal level of all resin cements (P<.05), whereas it was dominantly adhesive at the apical level. CONCLUSION All resin cement groups showed decreases in bond strengths at the middle or apical level except LuA and Uni. PMID:24049569

Effect of Adhesive Cementation Strategies on the Bonding of Y-TZP to Human Dentin.

PubMed

Alves, Mll; Campos, F; Bergoli, C D; Bottino, M A; Özcan, M; Souza, Roa

2016-01-01

This study evaluated the effects of different adhesive strategies on the adhesion of zirconia to dentin using conventional and self-adhesive cements and their corresponding adhesive resins. The occlusal parts of human molars (N=80) were sectioned, exposing the dentin. The teeth and zirconia cylinders (N=80) (diameter=3.4 mm; height=4 mm) were randomly divided into eight groups according to the factors "surface conditioning" and "cement type" (n=10 per group). One conventional cement (CC: RelyX ARC, 3M ESPE) and one self-adhesive cement (SA: RelyX U200, 3M ESPE) and their corresponding adhesive resin (for CC, Adper Single Bond Plus; for SA, Scotchbond Universal Adhesive-SU) were applied on dentin. Zirconia specimens were conditioned either using chairside (CJ: CoJet, 30 μm, 2.5 bar, four seconds), laboratory silica coating (RC: Rocatec, 110 μm, 2.5 bar, four seconds), or universal primer (Single Bond Universal-UP). Nonconditioned groups for both cements acted as the control (C). Specimens were stored in water (37°C, 30 days) and subjected to shear bond strength (SBS) testing (1 mm/min). Data (MPa) were analyzed using two-way analysis of variance and a Tukey test (α=0.05). While surface conditioning significantly affected the SBS values (p=0.0001) (C

Curing mode affects bond strength of adhesively luted composite CAD/CAM restorations to dentin.

PubMed

Lührs, Anne-Katrin; Pongprueksa, Pong; De Munck, Jan; Geurtsen, Werner; Van Meerbeek, Bart

2014-03-01

To determine the effect of curing mode and restoration-surface pre-treatment on the micro-tensile bond strength (μTBS) to dentin. Sandblasted CAD/CAM composite blocks (LAVA Ultimate, 3M ESPE) were cemented to bur-cut dentin using either the etch & rinse composite cement Nexus 3 ('NX3', Kerr) with Optibond XTR ('XTR', Kerr), or the self-etch composite cement RelyX Ultimate ('RXU', 3M ESPE) with Scotchbond Universal ('SBU', 3M ESPE). All experimental groups included different 'curing modes' (light-curing of adhesive and cement ('LL'), light-curing of adhesive and auto-cure of cement ('LA'), co-cure of adhesive through light-curing of cement ('AL'), or complete auto-cure ('AA')) and different 'restoration-surface pre-treatments' of the composite block (NX3: either a silane primer (Kerr), or the XTR adhesive; RXU: either silane primer (RelyX Ceramic Primer, 3M ESPE) and SBU, or solely SBU). After water-storage (7 days, 37°C), the μTBS was measured. Additionally, the degree of conversion (DC) of both cements was measured after 10min and after 1 week, either auto-cured (21°C/37°C) or light-cured (directly/through 3-mm CAD/CAM composite). The linear mixed-effects model (α=0.05) revealed a significant influence of the factors 'curing mode' and 'composite cement', and a less significant effect of the factor 'restoration-surface pre-treatment'. Light-curing 'LL' revealed the highest μTBS, which decreased significantly for all other curing modes. For curing modes 'AA' and 'AL', the lowest μTBS and a high percentage of pre-testing failures were reported. Overall, DC increased with light-curing and incubation time. The curing mode is decisive for the bonding effectiveness of adhesively luted composite CAD/CAM restorations to dentin. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Resistance to bond degradation between dual-cure resin cements and pre-treated sintered CAD-CAM dental ceramics

PubMed Central

Osorio, Raquel; Monticelli, Francesca; Osorio, Estrella; Toledano, Manuel

2012-01-01

Objective: To evaluate the bond stability of resin cements when luted to glass-reinforced alumina and zirconia CAD/CAM dental ceramics. Study design: Eighteen glass-infiltrated alumina and eighteen densely sintered zirconia blocks were randomly conditioned as follows: Group 1: No treatment; Group 2: Sandblasting (125 µm Al2O3-particles); and Group 3: Silica-coating (50 µm silica-modified Al2O3-particles). Composite samples were randomly bonded to the pre-treated ceramic surfaces using different resin cements: Subgroup 1: Clearfil Esthetic Cement (CEC); Subgroup 2: RelyX Unicem (RXU); and Subgroup 3: Calibra (CAL). After 24 h, bonded specimens were cut into 1 ± 0.1 mm2 sticks. One-half of the beams were tested for microtensile bond strength (MTBS). The remaining one-half was immersed in 10 % NaOCl aqueous solution (NaOClaq) for 5 h before testing. The fracture pattern and morphology of the debonded surfaces were assessed with a field emission gun scanning electron microscope (FEG-SEM). A multiple ANOVA was conducted to analyze the contributions of ceramic composition, surface treatment, resin cement type, and chemical challenging to MTBS. The Tukey test was run for multiple comparisons (p < 0.05). Results: After 24 h, CEC luted to pre-treated zirconia achieved the highest MTBS. Using RXU, alumina and zirconia registered comparable MTBS. CAL failed prematurely, except when luted to sandblasted zirconia. After NaOClaq storage, CEC significantly lowered MTBS when luted to zirconia or alumina. RXU decreased MTBS only when bonded to silica-coated alumina. CAL recorded 100 % of pre-testing failures. Micromorphological alterations were evident after NaOClaq immersion. Conclusions: Resin-ceramic interfacial longevity depended on cement selection rather than on surface pre-treatments. The MDP-containing and the self-adhesive resin cements were both suitable for luting CAD/CAM ceramics. Despite both cements being prone to degradation, RXU luted to zirconia or untreated or sandblasted alumina showed the most stable interfaces. CAL experimented spontaneous debonding in all tested groups. Key words:CAD/CAM ceramic, alumina, zirconia, resin cement, surface pre-treatment, sandblasting, silica-coating, chemical aging, bond degradation, microtensile bond strength. PMID:22322517

Influence of Immediate Dentin Sealing on the Shear Bond Strength of Pressed Ceramic Luted to Dentin with Self-Etch Resin Cement

PubMed Central

Dalby, Robert; Ellakwa, Ayman; Millar, Brian; Martin, F. Elizabeth

2012-01-01

Objectives. To examine the effect of immediate dentin sealing (IDS), with dentin bonding agents (DBAs) applied to freshly cut dentin, on the shear bond strength of etched pressed ceramic luted to dentin with RelyX Unicem (RXU) cement. Method. Eighty extracted noncarious third molars were ground flat to expose the occlusal dentin surfaces. The teeth were randomly allocated to five groups (A to E) of sixteen teeth each. Groups A to D were allocated a dentin bonding agent (Optibond FL, One Coat Bond, Single Bond, or Go!) that was applied to the dentin surface to mimic the clinical procedure of IDS. These specimen groups then had etched glass ceramic discs (Authentic) luted to the sealed dentin surface using RXU. Group E (control) had etched glass ceramic discs luted to the dentin surface (without a dentin bonding agent) using RXU following the manufacturer's instructions. All specimens were stored for one week in distilled water at room temperature and then shear stressed at a constant cross-head speed of 1 mm per minute until failure. Statistical analysis was performed by ANOVA followed by post hoc Tukey HSD method (P < 0.05) applied for multiple paired comparisons. Results. The shear bond strength results for group A to E ranged from 6.94 ± 1.53 to 10.03 ± 3.50 MPa. One-way ANOVA demonstrated a difference (P < 0.05) between the groups tested and the Tukey HSD demonstrated a significant (P < 0.05) difference between the shear bond strength (SBS) of Optibond FL (Group A) and Go! (Group D). There was no statistical difference (P > 0.05) in the SBS between the test groups (A–D) or the control (group E). Conclusion. IDS using the dentin bonding agents tested does not statistically (P > 0.05) affect the shear bond strength of etched pressed ceramic luted to dentin with RXU when compared to the control. PMID:22287963

Evaluation of bond strength of resin cements using different general-purpose statistical software packages for two-parameter Weibull statistics.

PubMed

Roos, Malgorzata; Stawarczyk, Bogna

2012-07-01

This study evaluated and compared Weibull parameters of resin bond strength values using six different general-purpose statistical software packages for two-parameter Weibull distribution. Two-hundred human teeth were randomly divided into 4 groups (n=50), prepared and bonded on dentin according to the manufacturers' instructions using the following resin cements: (i) Variolink (VAN, conventional resin cement), (ii) Panavia21 (PAN, conventional resin cement), (iii) RelyX Unicem (RXU, self-adhesive resin cement) and (iv) G-Cem (GCM, self-adhesive resin cement). Subsequently, all specimens were stored in water for 24h at 37°C. Shear bond strength was measured and the data were analyzed using Anderson-Darling goodness-of-fit (MINITAB 16) and two-parameter Weibull statistics with the following statistical software packages: Excel 2011, SPSS 19, MINITAB 16, R 2.12.1, SAS 9.1.3. and STATA 11.2 (p≤0.05). Additionally, the three-parameter Weibull was fitted using MNITAB 16. Two-parameter Weibull calculated with MINITAB and STATA can be compared using an omnibus test and using 95% CI. In SAS only 95% CI were directly obtained from the output. R provided no estimates of 95% CI. In both SAS and R the global comparison of the characteristic bond strength among groups is provided by means of the Weibull regression. EXCEL and SPSS provided no default information about 95% CI and no significance test for the comparison of Weibull parameters among the groups. In summary, conventional resin cement VAN showed the highest Weibull modulus and characteristic bond strength. There are discrepancies in the Weibull statistics depending on the software package and the estimation method. The information content in the default output provided by the software packages differs to very high extent. Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Bond Strength of Resin Cements to Zirconia Ceramic Using Adhesive Primers.

PubMed

Stefani, Ariovaldo; Brito, Rui Barbosa; Kina, Sidney; Andrade, Oswaldo Scopin; Ambrosano, Gláucia Maria Bovi; Carvalho, Andreia Assis; Giannini, Marcelo

2016-07-01

To evaluate the influence of adhesive primers on the microshear bond strength of resin cements to zirconia ceramic. Fifty zirconia plates (12 mm × 5 mm × 1.5 mm thick) of a commercially available zirconium oxide ceramic (ZirCad) were sintered, sandblasted with aluminum oxide particles, and cleaned ultrasonically before bonding. The plates were randomly divided into five groups of 10. Three resin cements were selected (RelyX ARC, Multilink Automix, Clearfil SA Cement self-adhesive resin cement), along with two primers (Metal-Zirconia Primer, Alloy Primer) and one control group. The primers and resin cements were used according to manufacturers' recommendations. The control group comprised the conventional resin cement (RelyX ARC) without adhesive primer. Test cylinders (0.75 mm diameter × 1 mm high) were formed on zirconia surfaces by filling cylindrical Tygon tube molds with resin cement. The specimens were stored in distilled water for 24 hours at 37°C, then tested for shear strength on a Shimadzu EZ Test testing machine at 0.5 mm/min. Bond strength data were analyzed statistically by two-way ANOVA and Dunnett's test (5%). The bond strength means in MPa (± s.d.) were: RelyX ARC: 28.1 (6.6); Multilink Automix: 37.6 (4.5); Multilink Automix + Metal-Zirconia Primer: 55.7 (4.0); Clearfil SA Cement: 46.2 (3.3); and Clearfil SA Cement + Alloy Primer: 47.0 (4.1). Metal-Zirconia Primer increased the bond strength of Multilink Automix resin cement to zirconia, but no effect was observed for Alloy Primer using Clearfil SA Cement. RelyX ARC showed the lowest bond strength to zirconia. © 2015 by the American College of Prosthodontists.

Influence of oval and circular post placement using different resin cements on push-out bond strength and void volume analysed by micro-CT.

PubMed

Uzun, I; Keleş, A; Arslan, H; Güler, B; Keskin, C; Gündüz, K

2016-12-01

To evaluate the percentage volume of voids within cement layers, to determine the push-out bond strength of circular and oval fibre posts luted with different commercial resin cements in oval cross-sectional root canals, and to correlate push-out bond strength values and volume of voids of circular and oval fibre posts. Seventy-two mandibular premolars with oval-shaped root canals were selected. The specimens were divided into two main groups according to the post type (oval and circular). Groups were further divided into three subgroups (n = 24) according to resin cement type: Maxcem Elite, Rely-X Unicem and Duo-Link. The volumes of voids within the cements were analysed by micro-computed tomography (micro-CT). The bond strength was then measured using a push-out test with an Instron universal testing machine. The failure modes were evaluated. Statistical analyses were performed using a three-way anova, Tukey's post hoc, Pearson's correlation and chi-square test (P = 0.05). The push-out bond strength values were significantly affected by root canal region, post type and cement type (P < 0.001). Root canal region, post type and cement type also significantly affected void volume (P < 0.001). There was a significant interaction between post type and cement type (P < 0.001). The most frequent failure type was adhesive failure in all the groups. There was no significant correlation between the push-out bond strength and void volume (P > 0.05). Void volume did not affect push-out bond strength of oval and circular posts luted in oval canals. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Vertical misfit of laser-sintered and vacuum-cast implant-supported crown copings luted with definitive and temporary luting agents

PubMed Central

Sánchez-Turrión, Andrés; López-Lozano, José F.; Albaladejo, Alberto; Torres-Lagares, Daniel; Montero, Javier; Suárez-García, Maria J.

2012-01-01

Objectives. This study aimed to evaluate the vertical discrepancy of implant-supported crown structures constructed with vacuum-casting and Direct Metal Laser Sintering (DMLS) technologies, and luted with different cement types. Study Design. Crown copings were fabricated using: (1) direct metal laser sintered Co-Cr (LS); (2) vacuum-cast Co-Cr (CC); and (3) vacuum-cast Ti (CT). Frameworks were luted onto machined implant abutments under constant seating pressure. Each alloy group was randomly divided into 5 subgroups (n = 10 each) according to the cement system utilized: Subgroup 1 (KC) used resin-modified glass-ionomer Ketac Cem Plus; Subgroup 2 (PF) used Panavia F 2.0 dual-cure resin cement; Subgroup 3 (RXU) used RelyX Unicem 2 Automix self-adhesive dual-cure resin cement; Subgroup 4 (PIC) used acrylic/urethane-based temporary Premier Implant Cement; and Subgroup 5 (DT) used acrylic/urethane-based temporary DentoTemp cement. Vertical misfit was measured by scanning electron microscopy (SEM). Two-way ANOVA and Student-Newman-Keuls tests were run to investigate the effect of alloy/fabrication technique, and cement type on vertical misfit. The statistical significance was set at α = 0.05. Results. The alloy/manufacturing technique and the luting cement affected the vertical discrepancy (p < 0.001). For each cement type, LS samples exhibited the best fit (p < 0.01) whereas CC and CT frames were statistically similar. Within each alloy group, PF and RXU provided comparably greater discrepancies than KC, PIC, and DT, which showed no differences. Conclusions. Laser sintering may be an alternative to vacuum-casting of base metals to obtain passive-fitting implant-supported crown copings. The best marginal adaptation corresponded to laser sintered structures luted with glass-ionomer KC, or temporary PIC or DT cements. The highest discrepancies were recorded for Co-Cr and Ti cast frameworks bonded with PF or RXU resinous agents. All groups were within the clinically acceptable misfit range. Key words:Dental alloy, laser sintering, implant-supported prostheses, vertical discrepancy, vertical misfit. PMID:22322524

Vertical discrepancy and microleakage of laser-sintered and vacuum-cast implant-supported structures luted with different cement types.

PubMed

Oyagüe, Raquel Castillo; Sánchez-Turrión, Andrés; López-Lozano, José Francisco; Suárez-García, M Jesús

2012-02-01

This study aimed to evaluate the vertical misfit and microleakage of laser-sintered and vacuum-cast cement-retained implant-supported frameworks. Three-unit implant-fixed structures were constructed with: (1) laser-sintered Co-Cr (LS); (2) vacuum-cast Co-Cr (CC); and (3) vacuum-cast Pd-Au (CP). Every framework was luted onto 2 prefabricated abutments under constant seating pressure. Each alloy group was randomly divided into three subgroups (n=10) according to the cement used: (1) Ketac Cem Plus (KC); (2) Panavia F 2.0 (PF); and (3) RelyX Unicem 2 Automix (RXU). After 30 days of water ageing, vertical discrepancy was measured by SEM, and marginal microleakage was scored using a digital microscope. Three-way ANOVA and Student-Newman-Keuls tests were run to investigate the effect of alloy/fabrication technique, FDP retainer, and cement type on vertical misfit. Data for marginal microleakage were analysed with Kruskal-Wallis and Dunn's tests (α=0.05). Vertical discrepancy was affected by alloy/manufacturing technique and cement type (p<0.001). Despite the luting agent, LS structures showed the best marginal adaptation, followed by CP, and CC. Within each alloy group, KC provided the best fit, whilst the use of PF or RXU resulted in no significant differences. Regardless of the framework alloy, KC exhibited the highest microleakage scores, whilst PF and RXU showed values that were comparable to each other. Laser-sintered Co-Cr structures achieved the best fit in the study. Notwithstanding the framework alloy, resin-modified glass-ionomer demonstrated better marginal fit but greater microleakage than did MDP-based and self-adhesive dual-cure resin cements. All groups were within the clinically acceptable misfit range. Laser-sintered Co-Cr may be an alternative to cast base metal and noble alloys to obtain passive-fitting structures. Despite showing higher discrepancies, resin cements displayed lower microleakage than resin-modified glass-ionomer. Further research is necessary to determine whether low microleakage scores may guarantee a suitable seal that could compensate for misfit. Copyright © 2011 Elsevier Ltd. All rights reserved.

Conventional dual-cure versus self-adhesive resin cements in dentin bond integrity

PubMed Central

da SILVA, Renata Andreza Talaveira; COUTINHO, Margareth; CARDOZO, Pedro Igor; da SILVA, Larissa Alves; ZORZATTO, José Roberto

2011-01-01

During post preparation, the root canal is exposed to the oral cavity, and endodontic treatment may fail because of coronal leakage, bacterial infection and sealing inability of the luting cement. Objective this study quantified the interfacial continuity produced with conventional dual-cure and self-adhesive resin cements in the cervical (C), medium (M) and apical (A) thirds of the root. Material and methods Forty single-rooted human teeth were restored using Reforpost # 01 conical glass-fiber posts and different materials (N=10 per group): group AC=Adper™ ScotchBond™ Multi-purpose Plus + AllCem; group ARC=Adper™ ScotchBond™ Multi-purpose Plus + RelyX ARC; group U100=RelyX U100; and group MXC=Maxcem Elite. After being kept in 100% humidity at 37ºC for 72 hours, the samples were sectioned parallel to their longitudinal axis and positive epoxy resin replicas were made. The scanning electron micrographs of each third section of the teeth were combined using Image Analyst software and measured with AutoCAD-2002. We obtained percentage values of the interfacial continuity. Results Interfacial continuity was similar in the apical, medium and cervical thirds of the roots within the groups (Friedman test, p>0.05). Comparison of the different cements in a same root third showed that interfacial continuity was lower in MXC (C=45.5%; M=48.5%; A=47.3%) than in AC (C=85.9%, M=81.8% and A=76.0%), ARC (C=83.8%, M=82.4% and A=75.0%) and U100 (C=84.1%, M=82.4% and A=77.3%) (Kruskal-Wallis test, p<0.05). Conclusions Allcem, Rely X ARC and U100 provide the best cementation; cementation was similar among root portions; in practical terms, U100 is the best resin because it combines good cementation and easy application and none of the cements provides complete interfacial continuity. PMID:21710099

Performance of universal adhesives on bonding to leucite-reinforced ceramic.

PubMed

Kim, Ryan Jin-Young; Woo, Jung-Soo; Lee, In-Bog; Yi, Young-Ah; Hwang, Ji-Yun; Seo, Deog-Gyu

2015-01-01

This study aimed to investigate the microshear bond strength of universal bonding adhesives to leucite-reinforced glass-ceramic. Leucite-reinforced glass-ceramic blocks were polished and etched with 9.5% hydrofluoric acid for 1 min. The specimens were assigned to one of four groups based on their surface conditioning (n = 16): 1) NC: negative control with no further treatment; 2) SBU: Single Bond Universal (3M ESPE); 3) ABU: ALL-BOND Universal (Bisco); and 4) PC: RelyX Ceramic Primer and Adper Scotchbond Multi-Purpose Adhesive (3M ESPE) as a positive control. RelyX Ultimate resin cement (3M ESPE) was placed on the pretreated ceramic and was light cured. Eight specimens from each group were stored in water for 24 h, and the remaining eight specimens were thermocycled 10,000 times prior to microshear bond strength evaluation. The fractured surfaces were examined by stereomicroscopy and scanning electron microscopy (SEM). After water storage and thermocycling, the microshear bond strength values decreased in the order of PC > SBU and ABU > NC (P < 0.05). Thermocycling significantly reduced the microshear bond strength, regardless of the surface conditioning used (P < 0.05). Cohesive failure in the ceramic and mixed failure in the ceramic and resin cement were observed in the fractured specimens. The percentage of specimens with cohesive failure after 24 h of water storage was: NC (50%), SBU (75%), ABU (75%), and PC (87%). After thermocycling, the percentage of cohesive failure in NC decreased to 25%; however, yet the percentages of the other groups remained the same. Although the bond strength between resin and hydrofluoric acid-etched glass ceramic was improved when universal adhesives were used, conventional surface conditioning using a separate silane and adhesive is preferable to a simplified procedure that uses only a universal adhesive for cementation of leucite-reinforced glass-ceramic.

Effect of zirconia surface treatment using nitric acid-hydrofluoric acid on the shear bond strengths of resin cements

PubMed Central

Kim, Sun Jai; Shim, June Sung

2017-01-01

PURPOSE The aim of this study was to compare the surface roughness of zirconia when using Zircos E etching system (ZSAT), applying a nitric acid-hydrofluoric acid compound as a pretreatment agent, and also to compare the shear bonding strength according to different resin cements. MATERIALS AND METHODS ZSAT, air abrasion, and tribochemical silicacoating were applied on prepared 120 zirconia specimens (10 mm in diameter, 7 mm in height) using CAD/CAM. Each 12 specimens with 4 different resin cements (Panavia F 2.0, Rely X Unicem, Superbond C&B, and Hot bond) were applied to test interfacial bond strength. The statistical analysis was performed using SAS 9.1 (SAS Institute Inc., Cary, NC, USA). The results are as follows: after application of the ZSAT on the zirconia specimens, surface roughness value after 2-hour etching was higher than those after 1- and 3-hour etching on SEM images. RESULTS For Superbond C&B and Rely X Unicem, the specimens treated with ZSAT showed higher shear bond strength values than those treated with air abrasion and tribochemical silicacoating system. Regarding the failure mode of interface over cement and zirconia surface, Rely X Unicem and Hot bond showed cohesive failures and Panavia F 2.0 and Superbond C&B showed mixed failures. CONCLUSION Zircos E etching system in zirconia restoration could increase its shear bond strength. However, its long term success rate and clinical application should be further evaluated. PMID:28435615

Evaluation of degree of conversion and the effect of thermal aging on the color stability of resin cements and flowable composite.

PubMed

Prieto, Lúcia Trazzi; Pimenta de Araújo, Cíntia Tereza; Araujo Pierote, Josué Junior; Salles de Oliveira, Dayane Carvalho Ramos; Coppini, Erick Kamiya; Sartini Paulillo, Luís Alexandre Maffei

2018-01-01

The aim of this in vitro study was to evaluate the color stability and degree of conversion (DC) of dual-cure and light-cure cements and flowable composites after thermal aging. A total of 50 human incisors were prepared and divided into six groups ( n = 10). Veneers were fabricated using IPS Empress Direct composite resin were bonded with three types of luting agents: Light-cured, conventional dual, and flowable composite according to the manufacturer's instructions. The groups were as follows: Filtek Z350XT Flow/Single Bond 2, RelyX ARC/Single Bond 2, RelyX Veneer/Single Bond 2, Tetric N-Flow/Tetric N-Bond, and Variolink II/Tetric N-Bond. Commission Internationale de l'Éclairage L*, a* and b* color coordinates were measured 24 h after cementation procedure with a color spectrophotometer and reevaluated after 10,000 thermal cycles. To evaluate the DC 50 specimens ( n = 10) of each resin material were obtained and Fourier transform infrared spectroscopy was used to evaluate the absorption spectra. Statistical analysis was performed with one-way ANOVA and Tukey's test (α = 0.05). No statistically significant differences in ΔE* occurred after aging. The greatest change in lightness occurred in the Variolink II resin cement. Changes in red-green hue were very small for the same cement and largest in the Tetric N-Flow flowable resin composite, while the greatest change in blue-yellow hue was a yellowing of the RelyX ARC luting cement. RelyX ARC exhibited the highest DC, and there were no statistically significant differences in DC among the other cements. Resin-based luting agent might affect the final of ceramic veneer restorations. The thermal aging affected the final color of the evaluated materials, and these were regarded as clinically unacceptable (ΔE >3.3).

Changes on degree of conversion of dual-cure luting light-cured with blue LED

NASA Astrophysics Data System (ADS)

Bandéca, M. C.; El-Mowafy, O.; Saade, E. G.; Rastelli, A. N. S.; Bagnato, V. S.; Porto-Neto, S. T.

2009-05-01

The indirect adhesive procedures constitute recently a substantial portion of contemporary esthetic restorative treatments. The resin cements have been used to bond tooth substrate and restorative materials. Due to recently introduction of the self-bonding resin luting cement based on a new monomer, filler and initiation technology has become important to study the degree of conversion of these new materials. In the present work the polymerization reaction and the filler content of dual-cured dental resin cements were studied by means of infra-red spectroscopy (FT-IR) and thermogravimetry (TG). Twenty specimens were made in a metallic mold (8 mm diameter × 1 mm thick) from each of 2 cements, Panavia® F2.0 (Kuraray) and RelyX™ Unicem Applicap (3M/ESPE). Each specimen was cured with blue LED with power density of 500 mW/cm2 for 30 s. Immediately after curing, 24 and 48 h, and 7 days DC was determined. For each time interval 5 specimens were pulverized, pressed with KBr and analyzed with FT-IR. The TG measurements were performed in Netzsch TG 209 under oxygen atmosphere and heating rate of 10°C/min from 25 to 700°C. A two-way ANOVA showed DC (%) mean values statistically significance differences between two cements ( p < 0.05). The Tukey’s test showed no significant difference only for the 24 and 48 h after light irradiation for both resin cements ( p > 0.05). The Relx-Y™ Unicem mean values were significantly higher than Panavia® F 2.0. The degree of conversion means values increasing with the storage time and the filler content showed similar for both resin cements.

Relined fiberglass post: an ex vivo study of the resin cement thickness and dentin-resin interface.

PubMed

Souza, Niélli Caetano de; Marcondes, Maurem Leitão; Breda, Ricardo Vaz; Weber, João Batista Blessmann; Mota, Eduardo Gonçalves; Spohr, Ana Maria

2016-08-18

The aim of this study was to evaluate the thickness of resin cements in the root thirds when using conventional fiberglass posts (CP) and relined fiberglass posts (RP) in weakened roots and to evaluate the morphological characteristics of the dentin-resin interface. Forty human maxillary anterior teeth had the crown sectioned below the cemento-enamel junction. The canals were endodontically treated and weakened with diamond burs. Teeth were divided into four groups (n = 10): Group 1 - CP + RelyX ARC; Group 2 - CP + RelyX U200; Group 3 - RP + RelyX ARC; and Group 4 - RP + RelyX U200. Prior to luting, 0.1% Fluorescein and 0.1% Rhodamine B dyes were added to an adhesive and resin cement, respectively. Slices were obtained from the apical, middle, and cervical thirds of the root. Confocal laser scanning microscopy images were recorded in four areas (buccal, lingual, mesial, distal) of each third. In each area, four equidistant measures of the resin cement were made and the mean value was calculated. The interface morphology was observed. The data were submitted to three-way ANOVA and Tukey's test (α = 0.05). The interaction between fiberglass posts, resin cement, and root thirds was significant (p < 0.0001). The resin cement thicknesses were significantly lower for RP in comparison with CP, except in the apical third. There was no significant difference between the resin cements for RP. There was formation of resin cement tags and adhesive tags along the root for RP. RP favored the formation of thin and uniform resin cement films and resin tags in weakened roots.

Genotoxic and cytotoxic effects of different types of dental cement on normal cultured human lymphocytes.

PubMed

Bakopoulou, A; Mourelatos, D; Tsiftsoglou, A S; Giassin, N P; Mioglou, E; Garefis, P

2009-01-31

In this study we have investigated the genotoxic and cytotoxic effects of eluates derived from different types of commercially available dental cements, including glass ionomer cements (GICs) (Ketac Cem/3M ESPE and GC Fuji I/GC Corp), resin-modified glass ionomer cements (RM-GICs) (RelyX Luting/3M ESPE and Vitrebond/3M ESPE) and dual-cure resin cements (RCs) (Variolink II/ Ivoclar-Vivadent and Panavia F 2.0/Kuraray) on normal cultured human lymphocytes. Lymphocyte primary cultures obtained from blood samples of three healthy donors were exposed to serial dilutions of eluates derived from specimens of each material tested. Metaphases were induced with phytohaemagglutinin, collected after 72h treatment by use of colchicine and stained according to the fluorescence plus giemsa (FPG) procedure. Preparations were scored for sister chromatid exchange (SCE) and chromosomal aberrations (CAs), while the proliferation rate index (PRI) was also calculated. Our results show that eluates derived from the RM-GICs and RCs caused severe genotoxic effects by significantly increasing the frequencies of SCEs and CAs in cultures of peripheral blood lymphocytes and by decreasing the relevant PRI values in a dose-dependent manner, whereas the two GICs caused only minor cytogenetic effects. Eluates of the two RM-GICs (Vitrebond and RelyX) were also very cytotoxic, as the first serial dilutions of both materials caused a complete mitotic arrest in lymphocyte cultures. Overall, the degree of genotoxicity and cytotoxicity caused by dental cements decreased as follows: Viterbond>Rely X>Panavia F 2.0>Variolink II>Ketac Cem=GC Fuji I. These results indicate that different types of dental cement differ extensively in their genotoxic and cytotoxic potential and their ability to affect chromosomal integrity, cell-cycle progression, DNA replication and repair. Although these results cannot be directly extrapolated to the clinical situation, the potential occurrence of adverse effects caused by the RM-GICs and RCs tested in this study should be considered when making a clinical decision about dental cements.

[Effect of the thickness of reinforced glass ceramics on the degree of conversion of dual-cure resin cements].

PubMed

Zhu, Lin-Lin; Qiu, Li-Hong; Liu, Li-Yang; Li, Xiao-Lin

2017-10-01

To determine the effect of the thickness of reinforced glass ceramics on the degree of conversion (DC) of three dual-cure resin cements (Multilink N, RelyX Ultimate and NX3-Nexus). Upcera reinforced glass ceramics and IPS e.max CAD test specimen were processed, with different thickness, transmittance was tested by ultraviolet and visible spectrometer. The DC was evaluated using Fourier transform infrared (FT-IR) spectrometer, then the degree of conversion of polymerization before and after curing was calculated. SPSS 21.0 software package was used for data analysis. Transmittance decreased along with the thickness of reinforced glass ceramics increased. At 2 mm -thickness transmittance of upcera lithium disilicate glass ceramics was superior to IPS e.max CAD. The DC of dual-cured resin cement was decreased with the increase of thickness. At the same 2 mm group, the DC of Multilink N and RelyX Ultimate under upcera lithium disilicate glass ceramics were superior to that under IPS e.max CAD groups. At 2 mm-thickness transmittance of upcera lithium disilicate glass ceramics was superior to IPS e.max CAD. At the same 2 mm group, the DC of Multilink N and RelyX Ultimate under upcera lithium disilicate glass ceramics were superior to that under IPS e.max CAD groups.

Clinical acceptability of two self-etch adhesive resins for the bonding of orthodontic brackets to enamel.

PubMed

Schnebel, Bradley; Mateer, Scott; Maganzini, Anthony Louis; Freeman, Katherine

2012-12-01

To determine whether two self-adhesive resin cements, Clearfil SA and RelyX, can be used to successfully bond orthodontic brackets to enamel. Seventy extracted premolars were custom mounted, cleaned and randomly divided into three groups. In group 1 (control), orthodontic brackets were bonded to 25 premolars using the Transbond Plus and Transbond XT two step adhesive systerm adhesive. In group 2, brackets were bonded to 25 premolars using Clearfil SA. In group 3, brackets were bonded to 20 premolars using RelyX. The brackets were debonded using a universal testing machine and shear bond strengths recorded. After debonding, each tooth was examined under 20× magnification to evaluate the residual adhesive remaining. An ANOVA with Duncan's Multiple Range Test was used to determine whether there were significant differences in shear bond strength between the groups. A Kruskal-Wallis Test and a Bonferroni multiple comparison procedure were used to compare the bond failure modes (adhesive remnant index scores) between the groups. The mean shear bond strengths for the brackets bonded using Clearfil SA and RelyX were 5·930±1·840 and 3·334±1·953 MPa, respectively. Both were significantly lower than that for the brackets bonded using Transbond (7·875±3·611 MPa). Both self-etch adhesive resin cement groups showed a greater incidence of bracket failure at the enamel/adhesive interface while the Transbond group showed a higher incidence at the bracket/adhesive interface. The shear bond strengths of the self-etch adhesive resin cements may be inadequate to successfully bond orthodontic brackets to enamel.

[Research on bond durability among different core materials and zirconia ceramic cemented by self-adhesive resin cements].

PubMed

Xinyu, Luo; Xiangfeng, Meng

2017-02-01

This research estimated shear bond durability of zirconia and different substrates cemented by two self-adhesive resin cements (Clearfil SA Luting and RelyX U100) before and after aging conditioning. Machined zirconia ceramic discs were cemented with four kinds of core material (cobalt-chromium alloy, flowable composite resin core material, packable composite resin, and dentin) with two self-adhesive resin cements (Clearfil SA Luting and RelyX U100). All specimens were divided into eight test groups, and each test group was divided into two subgroups. Each subgroup was subjected to shear test before and after 10 000 thermal cycles. All factors (core materials, cements, and thermal cycle) significantly influenced bond durability of zirconia ceramic (P<0.00 1). After 10 000 thermal cycles, significant decrease was not observed in shear bond strength of cobalt-chromium alloy luted with Clearfil SA Luting (P>0.05); observed shear bond strength was significantly higher than those of other substrates (P<0.05). Significantly higher shear bond strength was noted in Clearfil SA Luting luted with cobalt-chromium alloy, flowable composite resin core material, and packable composite resin than that of RelyX U100 (P<0.05). However, significant difference was not observed in shear bond strength of dentin luted with Clearfil SA Luting and RelyX U100 (P>0.05). Different core materials and self-adhesive resin cements can significantly affect bond durability of zirconia ceramic. 
.

Changes in degree of conversion and microhardness of dental resin cements.

PubMed

Yan, Yong Li; Kim, Young Kyung; Kim, Kyo-Han; Kwon, Tae-Yub

2010-01-01

There are few studies available on the post-light activation or post-mix polymerization of dental resin cements as a function of time. This in vitro study evaluated the successive changes in the degree of conversion (DC) and microhardness during polymerization of six commercial resin cements (light-cured [Choice 2, RelyX Veneer], chemical-cured [Multilink, C&B Cement] and dual-cured [Calibra, RelyX ARC]) within the first 24 hours and up to seven days. Resin specimens were prepared for Fourier transform infrared (FTIR) spectroscopy and microhardness testing to determine the DC and Vickers hardness (VH), respectively. The light-cured materials or mixed pastes of the dual-cured materials were irradiated with a light-curing unit (Elipar TriLight) through a precured composite overlay for 40 seconds. The FTIR spectra and microhardness readings were taken at specified times: 1, 2, 5, 10, 15, 30 and 60 minutes; 24 hours and after two days and seven days. According to the FTIR study, most of the curing reaction of Choice 2 and RelyX Veneer occurred within 10 and 30 minutes, respectively. Multilink, C&B Cement and Calibra exhibited gradual increases in the DC up to 24 hours, with no further statistically significant increase (p > 0.05). RelyX ARC attained a DC value within five minutes, similar to that at seven days (p > 0.05). Choice 2 and RelyXARC showed gradual increases in the VH, up to 15 minutes, with no further significant change over the remaining observation time (p > 0.05). For RelyX Veneer, Multilink, C&B Cement and Calibra, there were no significant increases in the VH value after 24 hours (p > 0.05). The light-cured materials produced significantly higher DC values than the chemical-cured materials (p < 0.05). The DC values of the two dual-cured resin cements were significantly different from each other (p < 0.001). The results suggest that the significant polymerization reaction was finished within 24 hours post-mix or post-light activation for all resin cements tested.

Effect of immediate or delayed light activation on curing kinetics and shrinkage stress of dual-cure resin cements.

PubMed

Faria-e-Silva, Andre; Boaro, Leticia; Braga, Roberto; Piva, Evandro; Arias, Vanessa; Martins, Luis

2011-01-01

This study evaluated the effect of light activation (absence, immediate, or delayed) on conversion kinetics and polymerization stress of three commercial dual-cured resin cements (Enforce, RelyX ARC, and Panavia F). Degree of conversion (DC) was monitored for 30 minutes using real-time near–Fourier transform infrared spectroscopy. The cement was mixed, placed on the spectrometer sample holder, and light activated either immediately or after five minutes (delayed light activation). When no light activation was performed, the materials were protected from light exposure (control). DC was evaluated at five and 30 minutes postmixture. Maximum rates of polymerization (Rp(max)) were obtained from the first derivative of the DC vs time curve. Polymerization stress was monitored for 30 minutes in 1-mm-thick specimens inserted between two cylinders attached to a universal testing machine. Data were submitted to analysis of variance/Tukey tests (α=0.05). Immediate light activation promoted the highest DC at five minutes. At 30 minutes, only RelyX ARC did not present a significant difference in DC between activation modes. Enforce and Panavia F presented higher Rp(max) for immediate and delayed light-activation, respectively. RelyX ARC showed similar Rp(max) for all activation modes. The absence of light activation resulted in the lowest stress followed by delayed light activation, while immediate light activation led to the highest values. RelyX ARC showed higher stress than Enforce, while the stress of Panavia F was similar to that of the others. Delayed light activation reduced the polymerization stress of the resin cements tested without jeopardizing DC.

Influence of chlorhexidine on dentin adhesive interface micromorphology and nanoleakage expression of resin cements.

PubMed

Stape, Thiago Henrique Scarabello; Menezes, Murilo De Sousa; Barreto, Bruno De Castro Ferreira; Naves, Lucas Zago; Aguiar, Flávio Henrique Baggio; Quagliatto, Paulo Sérgio; Martins, Luís Roberto Marcondes

2013-08-01

This study focused on adhesive interface morphologic characterization and nanoleakage expression of resin cements bonded to human dentin pretreated with 1% chlorhexidine (CHX). Thirty-two non-carious human third molars were ground flat to expose superficial dentin. Resin composite blocks were luted to the exposed dentin using one conventional (RelyX ARC) and one self-adhesive resin cement (RelyX U100), with/without CHX pretreatment. Four groups (n = 8) were obtained: control groups (ARC and U100); experimental groups (ARC/CHX and U100/CHX) were pretreated with 1% CHX prior to the luting process. After storage in water for 24 h, the bonded teeth were sectioned into 0.9 × 0.9 mm(2) sticks producing a minimum of 12 sticks per tooth. Four sticks from each tooth were prepared for hybrid layer evaluation by scanning electron microscope analysis. The remaining sticks were immersed in silver nitrate for 24 h for either nanoleakage evaluation along the bonded interfaces or after rupture. Nanoleakage samples were carbon coated and examined using backscattered electron mode. Well-established hybrid layers were observed in the groups luted with RelyX ARC. Nanoleakage evaluation revealed increase nanoleakage in groups treated with CHX for both resin cements. Group U100/CHX exhibited the most pronouncing nanoleakage expression along with porous zones adjacent to the CHX pretreated dentin. The results suggest a possible incompatibility between CHX and RelyX U100 that raises the concern that the use of CHX with self-adhesive cements may adversely affect resin-dentin bond. Copyright © 2013 Wiley Periodicals, Inc.

Tensile Bond Strength of Self Adhesive Resin Cement After Various Surface Treatment of Enamel.

PubMed

Sekhri, Sahil; Mittal, Sanjeev; Garg, Sandeep

2016-01-01

In self adhesive resin cements adhesion is achieved to dental surface without surface pre-treatment, and requires only single step application. This makes the luting procedure less technique-sensitive and decreases postoperative sensitivity. The purpose of this study was to evaluate bond strength of self adhesive resin after surface treatment of enamel for bonding base metal alloy. On the labial surface of 64 central incisor rectangular base metal block of dimension 6 mm length, 5mm width and 1 mm height was cemented with RelyX U200 and Maxcem Elite self adhesive cements with and without surface treatment of enamel. Surface treatment of enamel was application of etchant, one step bonding agent and both. Tensile bond strength of specimen was measured with universal testing machine at a cross head speed of 1mm/min. Least tensile bond strength (MPa) was in control group i.e. 1.33 (0.32) & 1.59 (0.299), Highest bond strength observed when enamel treated with both etchant and bonding agent i.e. 2.72 (0.43) & 2.97 (0.19) for Relyx U200 and Elite cement. When alone etchant and bonding agent were applied alone bond strength is 2.19 (0.18) & 2.24 (0.47) for Relyx U200, and 2.38 (0.27) 2.49 (0.16) for Max-cem elite. Mean bond strength was higher in case of Max-cem Elite as compared to RelyX U200 resin cement, although differences were non-significant (p > 0.05). Surface treatment of enamel increases the bond strength of self adhesive resin cement.

Retention Strength of PMMA/UDMA-Based Crowns Bonded to Dentin: Impact of Different Coupling Agents for Pretreatment

PubMed Central

Stawarczyk, Bogna; Teuss, Simona; Eichberger, Marlis; Roos, Malgorzata; Keul, Christine

2015-01-01

Computer aided design/computer aided manufacturing (CAD/CAM) polymers for long-term dental restorations benefit from enhanced mechanical properties. However, the quantification of their bonding properties on teeth is lacking. Therefore, the aim of this study was to determine the retention strength (RS) of differently pretreated new developed polymethylmethacrylate/urethanedimethacrylate-based CAD/CAM polymer bonded on dentin. In summary, 120 human caries-free molars were prepared, and polymeric crowns were milled and pretreated (n = 20): visio.link (VL), Scotchbond Universal (SU), Monobond Plus/Heliobond (MH), Margin Bond (MB), Margin Bond mixed with acetone (1:1) (MBA) or not pretreated (CG). Half of the specimens were cemented using Variolink II and the other half with RelyX Ultimate. Specimens were stored for 24 h in distilled water and thermal cycled (5000 ×, 5 °C/55 °C). The retention load was measured and failure types were defined. RS was calculated and analyzed using both two- and one-way ANOVA with a post-hoc Scheffé-test, unpaired t-test, Kaplan–Meier with Breslow–Gehan test and chi-squared test (p < 0.05). Crowns bonded using RelyX Ultimate showed higher RS than those bonded using Variolink II. The pretreatment showed no impact on the RS. However, survival analysis within Variolink II found an impact of pretreatment. The median RS for MH was the lowest and statistically different from MB, MBA and CG. For Variolink II MH had the poorest survival as the estimated cumulative failure function of the debonded crown increased very quickly with increasing TBS. Within the RelyX Ultimate groups, no significant differences were determined. The newly developed CAD/CAM polymer showed the highest bonding properties after cementation using RelyX Ultimate. PMID:28793651

Tensile Bond Strength of Self Adhesive Resin Cement After Various Surface Treatment of Enamel

PubMed Central

Sekhri, Sahil; Garg, Sandeep

2016-01-01

Introduction In self adhesive resin cements adhesion is achieved to dental surface without surface pre-treatment, and requires only single step application. This makes the luting procedure less technique-sensitive and decreases postoperative sensitivity. Aim The purpose of this study was to evaluate bond strength of self adhesive resin after surface treatment of enamel for bonding base metal alloy. Materials and Methods On the labial surface of 64 central incisor rectangular base metal block of dimension 6 mm length, 5mm width and 1 mm height was cemented with RelyX U200 and Maxcem Elite self adhesive cements with and without surface treatment of enamel. Surface treatment of enamel was application of etchant, one step bonding agent and both. Tensile bond strength of specimen was measured with universal testing machine at a cross head speed of 1mm/min. Results Least tensile bond strength (MPa) was in control group i.e. 1.33 (0.32) & 1.59 (0.299), Highest bond strength observed when enamel treated with both etchant and bonding agent i.e. 2.72 (0.43) & 2.97 (0.19) for Relyx U200 and Elite cement. When alone etchant and bonding agent were applied alone bond strength is 2.19 (0.18) & 2.24 (0.47) for Relyx U200, and 2.38 (0.27) 2.49 (0.16) for Max-cem elite. Mean bond strength was higher in case of Max-cem Elite as compared to RelyX U200 resin cement, although differences were non–significant (p > 0.05). Conclusion Surface treatment of enamel increases the bond strength of self adhesive resin cement. PMID:26894165

Mechanical properties of resin cements with different activation modes.

PubMed

Braga, R R; Cesar, P F; Gonzaga, C C

2002-03-01

Dual-cured cements have been studied in terms of the hardness or degree of conversion achieved with different curing modes. However, little emphasis is given to the influence of the curing method on other mechanical properties. This study investigated the flexural strength, flexural modulus and hardness of four proprietary resin cements. Materials tested were: Enforce and Variolink II (light-, self- and dual-cured), RelyX ARC (self- and dual-cured) and C & B (self-cured). Specimens were fractured using a three-point bending test. Pre-failure loads corresponding to specific displacements of the cross-head were used for flexural modulus calculation. Knoop hardness (KHN) was measured on fragments obtained after the flexural test. Tests were performed after 24 h storage at 37 degrees C. RelyX ARC dual-cured showed higher flexural strength than the other groups. RelyX ARC and Variolink II depended upon photo-activation to achieve higher hardness values. Enforce showed similar hardness for dual- and self-curing modes. No correlation was found between flexural strength and hardness, indicating that other factors besides the degree of cure (e.g. filler content and monomer type) affect the flexural strength of composites. No statistical difference was detected in the flexural modulus among the different groups.

Influence of 2% chlorhexidine digluconate on bond strength of a glass-fibre post luted with resin or glass-ionomer based cement.

PubMed

de Araújo, Diana Ferreira Gadelha; Chaves, Larissa Pinceli; Bim, Odair; Pimentel Garcia, Fernanda Cristina; Ishikiriama, Sérgio Kiyoshi; Honório, Heitor Marques; Wang, Linda

2014-06-01

This study evaluated the influence of 2% chlorhexidine digluconate (CHX) on the bond strength (BS) of a glass-fibre post to the root canal, regarding the cements (dual-cured resin or resin-modified glass-ionomer cement), the root thirds and the time of storage. Eighty bovine roots were selected and endodontically treated, before being randomly assigned to the following groups according to the luting protocol: ARC (RelyX ARC); ARC+CHX; RL (RelyX Luting 2); and RL+CHX. After 24 h of luting, the roots were sliced to obtain 1 mm-thick slices. Half of each group was submitted to either 7-day or 6-month storage in artificial saliva (n=10). The specimens were subjected to push-out tests with a crosshead speed of 0.5 mm/min. The data were analysed with four-way ANOVA and Tukey's test (P≤0.05). The failure modes were analysed with a digital microscope (50× and 200×). ARC yielded a significantly higher BS compared to RL (P<0.001). Despite CHX exerted a significant effect; it depends on the interaction with the luting cement and time (P<0.001). Thus, CHX decreased the values of BS to those of ARC after 6 months (P<0.001). On the 7th day of storage, the ARC+CHX presented higher BS to the cervical and middle thirds compared to RL+CHX (P=0.012). Time solely was not a significant factor (P=0.081). Adhesive cement-dentine type and mixed failures were predominant modes for the ARC groups. For the RL groups, the main failures were adhesive cement-post and mixed modes. Glass-fibre posts luted with RelyX ARC dual-cure resin cement exhibited higher BS than those luted with RelyX Luting 2 resin-modified glass-ionomer cement. Furthermore, CHX was not effective to improve the BS and negatively affected the BS of RelyX ARC after 6 months of storage. The use of chlorhexidine solution seems not to improve the bond strength of fibre posts to root canals, disregarding the composition of the luting cement. Copyright © 2014 Elsevier Ltd. All rights reserved.

The effect of various primers on shear bond strength of zirconia ceramic and resin composite.

PubMed

Sanohkan, Sasiwimol; Kukiattrakoon, Boonlert; Larpboonphol, Narongrit; Sae-Yib, Taewalit; Jampa, Thibet; Manoppan, Satawat

2013-11-01

To determine the in vitro shear bond strengths (SBS) of zirconia ceramic to resin composite after various primer treatments. Forty zirconia ceramic (Zeno, Wieland Dental) specimens (10 mm in diameter and 2 mm thick) were prepared, sandblasted with 50 μm alumina, and divided into four groups (n = 10). Three experimental groups were surface treated with three primers; CP (RelyX Ceramic Primer, 3M ESPE), AP (Alloy Primer, Kuraray Medical), and MP (Monobond Plus, Ivoclar Vivadent AG). One group was not treated and served as the control. All specimens were bonded to a resin composite (Filtek Supreme XT, 3M ESPE) cylinder with an adhesive system (Adper Scotchbond Multi-Purpose Plus Adhesive, 3M ESPE) and then stored in 100% humidity at 37°C for 24 h before SBS testing in a universal testing machine. Mean SBS (MPa) were analyzed with one-way analysis of variance (ANOVA) and the Tukey's Honestly Significant Difference (HSD) test (α = 0.05). Group AP yielded the highest mean and standard deviation (SD) value of SBS (16.8 ± 2.5 MPa) and Group C presented the lowest mean and SD value (15.4 ± 1.6 MPa). The SBS did not differ significantly among the groups (P = 0.079). Within the limitations of this study, the SBS values between zirconia ceramic to resin composite using various primers and untreated surface were not significantly different.

[Comparative study of 4 types of luting cements on shear bond strength of Zirconia ceramics to dentin].

PubMed

Yin, Bao-di; Zhang, Xian-fang; Zheng, Hu; Han, Dong-wei

2010-04-01

To investigate the adequate luting cements for zirconia ceramics to dentin. Blocks of sintered zirconia ceramics were randomly divided into 4 groups with 8 slices in each. After saliva immersion,airborne-particle abraded ceramic specimens were cleaned with phosphoric acid gel(containing 35% phosphoric acid) and then bonded to dentin with these four kinds of luting cements. After preserved in 37 degrees centigrade distilled water for 24 hours, the shear bonding strength of these specimens was tested and the data was analyzed with SPSS12.0 software package. The Multilink Automix could attain the highest shear bonding strength and the 3M RelyXTM Unicem AplicapTM could attain higher shear bonding strength, which were both significantly higher than in the Tokuso Ionomer and Shofu Polycarboxylate Cement groups(P<0.05). Total etching resin luting cement is an ideal option to the bonding of zirconia ceramics and can provide a strong bonding.

Fatigue resistance of ultrathin CAD/CAM complete crowns with a simplified cementation process.

PubMed

Magne, Pascal; Carvalho, Adriana O; Bruzi, Greciana; Giannini, Marcelo

2015-10-01

Traditional tooth preparation for complete crowns requires a substantial amount of hard tissue reduction. This is in contrast with the principles of minimally invasive dentistry. An ultrathin complete crown preparation is proposed instead. The purpose of this in vitro study was to assess the fatigue resistance and failure mode of computer-aided design and computer-aided manufacturing (CAD/CAM) ultrathin complete molar crowns placed with self-adhesive cement. Different restorative materials (resin nanoceramic [RNC], feldspathic ceramic [FEL], and lithium disilicate [LD]) were compared. Forty-five extracted molars with a standardized crown preparation were restored with the Cerec 3 CAD/CAM system using FEL, LD, or RNC (n=15). FEL and LD restorations were etched with hydrofluoric acid and silanated. RNC restorations and all preparations were treated with airborne-particle abrasion. All restorations (thickness=0.7 mm) were cemented with RelyX Unicem II Automix cement and submitted to cyclic isometric loading, beginning with a load of 200 N (5000 cycles) and followed by stages of 400, 600, 800, 1000, 1200, and 1400 N at a maximum of 30 000 cycles each. The specimens were loaded until failure or for a maximum of 185 000 cycles. The failure mode was categorized as "catastrophic," "possibly reparable," or "reparable." The groups were compared using life table survival analysis (log rank test at α=.05). Previously published data from the same authors about traditional complete crowns (thickness 1.5 mm) using the same experimental design were included for comparison. All specimens survived the fatigue test until the 600 N step. RNC, LD, and FEL failed at an average load of 1014 N (1 survival), 1123 N (2 survivals), and 987 N (no survivals), and no difference in survival rate was found. No catastrophic failures were reported after the fatigue test. Comparison with previously published data showed that 1.5-mm thick complete crowns demonstrated higher survival rates than the ultrathin restorations, independent of the material. The fatigue resistance of ultrathin complete molar crowns (placed with a simplified cementation process) made of RNC, LD, and FEL was not significantly different. All materials survived the normal range of masticatory forces. All failures were re-restorable. Regular crowns of 1.5 to 2.0 mm thickness may present higher survival rates than ultrathin ones. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Bonding effectiveness to different chemically pre-treated dental zirconia.

PubMed

Inokoshi, Masanao; Poitevin, André; De Munck, Jan; Minakuchi, Shunsuke; Van Meerbeek, Bart

2014-09-01

The objective of this study was to evaluate the effect of different chemical pre-treatments on the bond durability to dental zirconia. Fully sintered IPS e.max ZirCAD (Ivoclar Vivadent) blocks were subjected to tribochemical silica sandblasting (CoJet, 3M ESPE). The zirconia samples were additionally pre-treated using one of four zirconia primers/adhesives (Clearfil Ceramic Primer, Kuraray Noritake; Monobond Plus, Ivoclar Vivadent; Scotchbond Universal, 3M ESPE; Z-PRIME Plus, Bisco). Finally, two identically pre-treated zirconia blocks were bonded together using composite cement (RelyX Ultimate, 3M ESPE). The specimens were trimmed at the interface to a cylindrical hourglass and stored in distilled water (7 days, 37 °C), after which they were randomly tested as is or subjected to mechanical ageing involving cyclic tensile stress (10 N, 10 Hz, 10,000 cycles). Subsequently, the micro-tensile bond strength was determined, and SEM fractographic analysis performed. Weibull analysis revealed the highest Weibull scale and shape parameters for the 'Clearfil Ceramic Primer/mechanical ageing' combination. Chemical pre-treatment of CoJet (3M ESPE) sandblasted zirconia using Clearfil Ceramic Primer (Kuraray Noritake) and Monobond Plus (Ivoclar Vivadent) revealed a significantly higher bond strength than when Scotchbond Universal (3M ESPE) and Z-PRIME Plus (Bisco) were used. After ageing, Clearfil Ceramic Primer (Kuraray Noritake) revealed the most stable bond durability. Combined mechanical/chemical pre-treatment, the latter with either Clearfil Ceramic Primer (Kuraray Noritake) or Monobond Plus (Ivoclar Vivadent), resulted in the most durable bond to zirconia. As a standard procedure to durably bond zirconia to tooth tissue, the application of a combined 10-methacryloyloxydecyl dihydrogen phosphate/silane ceramic primer to zirconia is clinically highly recommended.

Influence of different adhesive systems on the pull-out bond strength of glass fiber posts.

PubMed

da Silva, Luciana Mendonça; Andrade, Andréa Mello de; Machuca, Melissa Fernanda Garcia; da Silva, Paulo Maurício Batista; da Silva, Ricardo Virgolino C; Veronezi, Maria Cecília

2008-01-01

This in vitro study evaluated the tensile bond strength of glass fiber posts (Reforpost - Angelus-Brazil) cemented to root dentin with a resin cement (RelyX ARC - 3M/ESPE) associated with two different adhesive systems (Adper Single Bond - 3M/ESPE and Adper Scotchbond Multi Purpose (MP) Plus - 3M/ESPE), using the pull-out test. Twenty single-rooted human teeth with standardized root canals were randomly assigned to 2 groups (n=10): G1- etching with 37% phosphoric acid gel (3M/ESPE) + Adper Single Bond + #1 post (Reforpost - Angelus) + four #1 accessory posts (Reforpin - Angelus) + resin cement; G2- etching with 37% phosphoric acid gel + Adper Scotchbond MP Plus + #1 post + four #1 accessory posts + resin cement. The specimens were stored in distilled water at 37 degrees C for 7 days and submitted to the pull-out test in a universal testing machine (EMIC) at a crosshead speed of 0.5 mm/min. The mean values of bond strength (kgf) and standard deviation were: G1- 29.163 +/- 7.123; G2- 37.752 +/-13.054. Statistical analysis (Student's t-test; a=0.05 showed no statistically significant difference (p<0.05) between the groups. Adhesive bonding failures between resin cement and root canal dentin surface were observed in both groups, with non-polymerized resin cement in the apical portion of the post space when Single Bond was used (G1). The type of adhesive system employed on the fiber post cementation did not influence the pull-out bond strength.

The shear bond strength of self-adhesive resin cements to dentin and enamel: an in vitro study.

PubMed

Rodrigues, Raphaela F; Ramos, Carla M; Francisconi, Paulo A S; Borges, Ana Flávia S

2015-03-01

Clinicians continue to search for ways to simplify bonding procedures without compromising clinical efficacy. The purpose of this study was to evaluate the shear strength of self-adhesive cements RelyX U100 and RelyX U200, and conventional resin cement RelyX ARC to enamel and dentin after different surface treatments. The crowns of 120 bovine incisor teeth were separated from the roots and embedded in epoxy resin in polyvinyl chloride tubes. In each tooth, the area to be cemented was delimited with central holed adhesive tape. The teeth were distributed into 12 groups (n=10) according to the substrate; etched or not with 37% phosphoric acid; and cement type of enamel-U100, enamel-phosphoric acid-U100, enamel-U200, enamel-phosphoric acid-U200, enamel-ARC, enamel-phosphoric acid-ARC, dentin-U100, dentin-phosphoric acid-U100, dentin-U200, dentin-phosphoric acid-U200, dentin-ARC, and dentin-phosphoric acid-ARC. After 7 days of storage in artificial saliva, shear strength tests were performed by using a universal testing machine (0.5 mm/min). The data were analyzed with 3-way ANOVA and the Tukey test (α=.05). Fracture analysis was performed with a light microscope. Two specimens from each group were analyzed with a scanning electron microscope. In enamel, ARC (9.96 MPa) had higher shear strength (P=.038) than U100 (5.14 MPa); however, after surface etching, U100 (17.81 MPa) and U200 (17.52 MPa) had higher shear strength (P<.001). With dentin, no significant differences were observed (P=.999), except for dentin-ARC (0.34 MPa) (P=.001). Most fractures were of the adhesive type. U200 self-adhesive cement had similar bond strength to the ARC in enamel, but the combination with phosphoric acid had the best bond strength. For dentin, self-adhesive resin cements are equally effective alternatives to conventional resin cement. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Influence of preheating the bonding agent of a conventional three-step adhesive system and the light activated resin cement on dentin bond strength

PubMed Central

Holanda, Daniel Brandão Vilela; França, Fabiana Mantovani Gomes; do Amaral, Flávia Lucisano Botelho; Flório, Flávia Martão; Basting, Roberta Tarkany

2013-01-01

Aims: to evaluate the influence of preheating the bonding agent (Scotchbond Multipurpose Adhesive/3M ESPE) and the light-activated resin cement (RelyX Venner/3M ESPE) on dentin microtensile bond strength. Materials and Methods: The exposed flat dentin surface of 40 human third molars were randomly distributed into four groups for cementation (SR Adoro/Ivoclar Vivadent) (n = 10): G1-bond and resin cement, both at room temperature (22°C), G2-bond preheated to 58°C and cement at room temperature (22°C), G3-bond at room temperature (22°C) and the cement preheated to 58°C, G4-bond preheated to 58°C and cement preheated to 58°C. Sticks of dentin/block set measuring approximately 1 mm2 were obtained and used for the microtensile bond strength test. All sticks had their failure mode classified. Statistical analysis used: Factorial analysis of variance was applied, 2 × 2 (bond × cement) (P < 0.05). Results: Preheating the bonding agent (P = 0.8411) or the cement (P = 0.7155), yielded no significant difference. The interaction bond × cement was not significant (P = 0.9389). Conclusions: Preheating the bond and/or the light-activated resin cement did not influence dentin bond strength or fracture failure mode. PMID:24347889

Effect of sulfuric acid etching of polyetheretherketone on the shear bond strength to resin cements.

PubMed

Sproesser, Oliver; Schmidlin, Patrick R; Uhrenbacher, Julia; Roos, Malgorzata; Gernet, Wolfgang; Stawarczyk, Bogna

2014-10-01

To examine the influence of etching duration on the bond strength of PEEK substrate in combination with different resin composite cements. In total, 448 PEEK specimens were fabricated, etched with sulfuric acid for 5, 15, 30, 60, 90, 120, and 300 s and then luted with two conventional resin cements (RelyX ARC and Variolink II) and one self-adhesive resin cement (Clearfil SA Cement) (n = 18/subgroup). Non-etched specimens served as the control group. Specimens were stored in distilled water for 28 days at 37°C and shear bond strengths were measured. Data were analyzed nonparametrically using Kruskal-Wallis-H (p < 0.05). Non-etched PEEK demonstrated no bond strength to resin composite cements. The optimal etching duration varied with the type of resin composite: 60 s for RelyX ARC (15.3 ± 7.2 MPa), 90 s for Variolink II (15.2 ± 7.2 MPa), and 120 s for Clearfil SA Cement (6.4 ± 5.9 MPa). Regardless of etching duration, however, the self-etching resin composite cement showed significantly lower shear bond strength values when compared to groups luted with the conventional resin composites. Although sulfuric acid seems to be suitable and effective for PEEK surface pre-treatment, further investigations are required to examine the effect of other adhesive systems and cements.

Comparison of the Microtensile Bond Strength of a Polyetherketoneketone (PEKK) Tooth Post Cemented with Various Surface Treatments and Various Resin Cements.

PubMed

Song, Chan-Hong; Choi, Jae-Won; Jeon, Young-Chan; Jeong, Chang-Mo; Lee, So-Hyoun; Kang, Eun-Sook; Yun, Mi-Jung; Huh, Jung-Bo

2018-05-29

The aim of this in-vitro research was to evaluate the microtensile bond strength in the newly introduced PEKK tooth post with various surface treatments and resin cements. A fiberglass tooth post was included in order to compare it with PEKK as a possible post material. The microtensile bond strengths of the fiberglass post (FRC Postec Plus) and the PEKK post (Pekkton ® ) were tested using three kinds of self-adhesive resin cements (G-CEM LinkAce, Multilink Speed, and RelyX U200) and one self-etching resin cement (PANAVIA F2.0). The surface treatments of the fiberglass posts were processed according to the manufacturer's recommendations (F1, application of 37% phosphoric acid etching gel and silanization). For the PEKK post groups, various surface treatments were performed like no surface treatment (P1), sandblasting (P2), silica-coating and silanization (P3), and sandblasting with a composite primer (P4). In the surface treatment, PEKK posts with silica coating and silane treatment (P3) showed a significantly higher microtensile bond strength (mean MPa: 18.09, p < 0.05). The highest microtensile bond strength was shown when the PEKK posts were treated with a silica coating and silane treatment and cemented with RelyX U200 (mean MPa: 22.22). The PEKK posts with surface treatments of silica-coating and silanization or sandblasting displayed superior microtensile bond strengths (mean MPa: 18.09 and 16.25, respectively) compared to the conventional fiberglass posts (mean MPa: 14.93, p < 0.05).

Cytotoxicity and biocompatibility of Zirconia (Y-TZP) posts with various dental cements

PubMed Central

Shin, Hyeongsoon; Ko, Hyunjung

2016-01-01

Objectives Endodontically treated teeth with insufficient tooth structure are often restored with esthetic restorations. This study evaluated the cytotoxicity and biological effects of yttria partially stabilized zirconia (Y-TZP) blocks in combination with several dental cements. Materials and Methods Pairs of zirconia cylinders with medium alone or cemented with three types of dental cement including RelyX U200 (3M ESPE), FujiCEM 2 (GC), and Panavia F 2.0 (Kuraray) were incubated in medium for 14 days. The cytotoxicity of each supernatant was determined using 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays on L929 fibroblasts and MC3T3-E1 osteoblasts. The levels of interleukin-6 (IL-6) mRNA were evaluated by reverse transcription polymerase chain reaction (RT-PCR), and IL-6 protein was evaluated by enzyme-linked immunosorbent assays (ELISA). The data were analyzed using one-way ANOVA and Tukey post-hoc tests. A p < 0.05 was considered statistically significant. Results The MTT assays showed that MC3T3-E1 osteoblasts were more susceptible to dental cements than L929 fibroblasts. The resin based dental cements increased IL-6 expression in L929 cells, but reduced IL-6 expression in MC3T3-E1 cells. Conclusions Zirconia alone or blocks cemented with dental cement showed acceptable biocompatibilities. The results showed resin-modified glass-ionomer based cement less produced inflammatory cytokines than other self-adhesive resin-based cements. Furthermore, osteoblasts were more susceptible than fibroblasts to the biological effects of dental cement. PMID:27508157

Cytotoxicity and biocompatibility of Zirconia (Y-TZP) posts with various dental cements.

PubMed

Shin, Hyeongsoon; Ko, Hyunjung; Kim, Miri

2016-08-01

Endodontically treated teeth with insufficient tooth structure are often restored with esthetic restorations. This study evaluated the cytotoxicity and biological effects of yttria partially stabilized zirconia (Y-TZP) blocks in combination with several dental cements. Pairs of zirconia cylinders with medium alone or cemented with three types of dental cement including RelyX U200 (3M ESPE), FujiCEM 2 (GC), and Panavia F 2.0 (Kuraray) were incubated in medium for 14 days. The cytotoxicity of each supernatant was determined using 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays on L929 fibroblasts and MC3T3-E1 osteoblasts. The levels of interleukin-6 (IL-6) mRNA were evaluated by reverse transcription polymerase chain reaction (RT-PCR), and IL-6 protein was evaluated by enzyme-linked immunosorbent assays (ELISA). The data were analyzed using one-way ANOVA and Tukey post-hoc tests. A p < 0.05 was considered statistically significant. The MTT assays showed that MC3T3-E1 osteoblasts were more susceptible to dental cements than L929 fibroblasts. The resin based dental cements increased IL-6 expression in L929 cells, but reduced IL-6 expression in MC3T3-E1 cells. Zirconia alone or blocks cemented with dental cement showed acceptable biocompatibilities. The results showed resin-modified glass-ionomer based cement less produced inflammatory cytokines than other self-adhesive resin-based cements. Furthermore, osteoblasts were more susceptible than fibroblasts to the biological effects of dental cement.

Effect of power toothbrushing on simulated wear of dental cement margins.

PubMed

Black, Marsha A; Bayne, Stephen C; Peterson, Charlotte A

2007-01-01

Power toothbrushes (PTBs), in combination with abrasive dentifrices, may encourage wear of dental cements at crown margins. The objective of this in vitro simulation was to control the clinical variables associated with PTB use and measure the potential side effects of PTBs with mild and abrasive dentifrices. Four PTBs ( Braun-Oral-B-Professional Care at 150 g brushing force, Sonicare-Elite at 90 g, Colgate-Actibrush at 200 g and Crest-Spinbrush-Pro at 250 g) and 2 dentifrices mixed 1:1 with tap water (Mild= Colgate-Total, Colgate-Palmolive; Abrasive= Close-up, Chesebrough-Ponds) versus tap water alone (control) were used to abrade 2 cements (Fleck's Mizzy Zinc Phosphate [ZP]; 3M-ESPE Unicem universal cement [UC]) using cement-filled slots (160 m wide) cut into wear-resistant ceramic blocks. A custom fixture controlled PTB/block alignment, PTB loads, and other testing variables. Wear was measured (3 profilometer traces/slot, 5 slots/block/group, baseline to 5-year differences) and analyzed (3-way ANOVA, p < or = 0.05, Bonferroni). Wear for ZP was much greater than UC (p<0.05) for all 4 PTBs and both dentifrices. Brushing with water showed no effects (p<0.05). Cement-PTB-dentifrice interactions did occur. Only minor differences occurred among PTBs. Pooled 5y-wear levels for ZP for both dentifrices approximately 21 microm /5y) were similar to values for current-day posterior composite materials. Combinations of PTBs with mild and abrasive dentifrices produced significant wear with ZP but not UC; thus, resin-composite cements seem to represent a better choice for wear resistance.

Impact of bleaching agents on water sorption and solubility of resin luting cements.

PubMed

Torabi Ardakani, Mahshid; Atashkar, Berivan; Bagheri, Rafat; Burrow, Michael F

2017-08-01

The aim of the present study was to evaluate the effect of distilled water and home and office bleaching agents on the sorption and solubility of resin luting cements. A total of 18 disc-shaped specimens were prepared from each of four resin cements: G-CEM LinkAce, Panavia F, Rely X Unicem, and seT. Specimens were cured according to the manufacturers' instructions and randomly divided into three groups of six, where they were treated with either an office or home bleaching agent or immersed in distilled water (control). Water sorption and solubility were measured by weighing the specimens before and after immersion and desiccation. Data were analyzed using Pearson correlation coefficient, two-way analysis of variance (ANOVA) and Tukey's test. There was a significant, positive correlation between sorption and solubility. Two-way anova showed significant differences among all resin cements tested for either sorption or solubility. Water sorption and solubility of all cements were affected significantly by office bleaching, and even more by home bleaching agents. Sorption and solubility behavior of the studied cements were highly correlated and significantly affected by applying either office or home bleaching agents; seT showed the highest sorption and solubility, whereas Rely X Unicem revealed the lowest. © 2016 John Wiley & Sons Australia, Ltd.

Influence of Photoinitiator on Accelerated Artificial Aging and Bond Strength of Experimental Resin Cements.

PubMed

Righi, Helouise; Costa, Ana Rosa; Oliveira, Dayane Carvalho Ramos Salles de; Abuna, Gabriel Flores; Sinhoreti, Mario Alexandre Coelho; Naufel, Fabiana Scarparo

2018-01-01

The goal of this study was to evaluate in vitro the effect of the photoinitiator phenylpropanedione (PPD), alone or combined with camphorquinone (CQ), on color stability of photoactivated resin cements and their bond strength to ceramics using a micro-shear test. Four resin cements were used: a commercial brand cement (RelyX Veneer®) and 3 experimental cements with different types and concentration of photoinitiators. For color analysis, ceramic discs were cemented on bovine dentin specimens to simulate indirect restorations (n=8) and were exposed to UV for 120 h and tested for color alteration using a reflectance spectrophotometer and the CIEL*a*b* system. Data were analyzed by Anova and Tukey's test at 5% significance level. The color test results did not present statistically significant difference for the ∆E for all the studied cements, neither for ∆L, ∆a and ∆b. For the bond strength, all the studied cements showed statistically significant differences to each other, with the highest result for the RelyX Veneer® (29.07 MPa) cement, followed by the cement with CQ (21.74 MPa) and CQ+PPD (19.09 MPa) cement; the lowest result was obtained by the cement using only PPD as a photoinitiator (13.99 MPa). So, based on the studied parameters, PPD was not advantageous as photoinitiator of resin cements, because it showed a low value of bond strength to the ceramics and no superior color stability.

Retentive force and microleakage of stainless steel crowns cemented with three different luting agents.

PubMed

Yilmaz, Yucel; Dalmis, Anya; Gurbuz, Taskin; Simsek, Sera

2004-12-01

The aim of this investigation was to compare the tensile strength, microleakage, and Scanning Electron Microscope (SEM) evaluations of SSCs cemented using different adhesive cements on primary molars. Sixty-three extracted primary first molars were used. Tooth preparations were done. Crowns were altered and adapted for investigation purpose, and then cemented using glass ionomer cement (Aqua Meron), resin modified cement (RelyX Luting), and resin cement (Panavia F) on the prepared teeth. Samples were divided into two groups of 30 samples each for tensile strength and microleakage tests. The remaining three samples were used for SEM evaluation. Data were analyzed with one-way ANOVA and Tukey test. The statistical analysis of ANOVA revealed significant differences among the groups for both tensile strength and microleakage tests (p < 0.05). Tukey test showed statistically significant difference between Panavia F and RelyX Luting (p < 0.05), but none between the others (p > 0.05). This study showed that the higher the retentive force a crown possessed, the lower would be the possibility of microleakage.

Improvement of enamel bond strengths for conventional and resin-modified glass ionomers: acid-etching vs. conditioning*

PubMed Central

Zhang, Ling; Tang, Tian; Zhang, Zhen-liang; Liang, Bing; Wang, Xiao-miao; Fu, Bai-ping

2013-01-01

Objective: This study deals with the effect of phosphoric acid etching and conditioning on enamel micro-tensile bond strengths (μTBSs) of conventional and resin-modified glass ionomer cements (GICs/RMGICs). Methods: Forty-eight bovine incisors were prepared into rectangular blocks. Highly-polished labial enamel surfaces were either acid-etched, conditioned with liquids of cements, or not further treated (control). Subsequently, two matching pre-treated enamel surfaces were cemented together with one of four cements [two GICs: Fuji I (GC), Ketac Cem Easymix (3M ESPE); two RMGICs: Fuji Plus (GC), RelyX Luting (3M ESPE)] in preparation for μTBS tests. Pre-treated enamel surfaces and cement-enamel interfaces were analyzed by scanning electron microscopy (SEM). Results: Phosphoric acid etching significantly increased the enamel μTBS of GICs/RMGICs. Conditioning with the liquids of the cements produced significantly weaker or equivalent enamel μTBS compared to the control. Regardless of etching, RMGICs yielded stronger enamel μTBS than GICs. A visible hybrid layer was found at certain enamel-cement interfaces of the etched enamels. Conclusions: Phosphoric acid etching significantly increased the enamel μTBSs of GICs/RMGICs. Phosphoric acid etching should be recommended to etch the enamel margins before the cementation of the prostheses such as inlays and onlays, using GICs/RMGICs to improve the bond strengths. RMGICs provided stronger enamel bond strength than GICs and conditioning did not increase enamel bond strength. PMID:24190447

Effect of reduced exposure times on the cytotoxicity of resin luting cements cured by high-power led

PubMed Central

ERGUN, Gulfem; EGILMEZ, Ferhan; YILMAZ, Sukran

2011-01-01

Objective Applications of resin luting agents and high-power light-emitting diodes (LED) light-curing units (LCUs) have increased considerably over the last few years. However, it is not clear whether the effect of reduced exposure time on cytotoxicity of such products have adequate biocompatibility to meet clinical success. This study aimed at assessing the effect of reduced curing time of five resin luting cements (RLCs) polymerized by high-power LED curing unit on the viability of a cell of L-929 fibroblast cells. Material and Methods Disc-shaped samples were prepared in polytetrafluoroethylene moulds with cylindrical cavities. The samples were irradiated from the top through the ceramic discs and acetate strips using LED LCU for 20 s (50% of the manufacturer's recommended exposure time) and 40 s (100% exposure time). After curing, the samples were transferred into a culture medium for 24 h. The eluates were obtained and pipetted onto L-929 fibroblast cultures (3x104 per well) and incubated for evaluating after 24 h. Measurements were performed by dimethylthiazol diphenyltetrazolium assay. Statistical significance was determined by two-way ANOVA and two independent samples were compared by t-test. Results Results showed that eluates of most of the materials polymerized for 20 s (except Rely X Unicem and Illusion) reduced to a higher extent cell viability compared to samples of the same materials polymerized for 40 s. Illusion exhibited the least cytotoxicity for 20 s exposure time compared to the control (culture without samples) followed by Rely X Unicem and Rely X ARC (90.81%, 88.90%, and 83.11%, respectively). For Rely X ARC, Duolink and Lute-It 40 s exposure time was better (t=-1.262 p=0,276; t=-9.399 p=0.001; and t=-20.418 p<0.001, respectively). Conclusion The results of this study suggest that reduction of curing time significantly enhances the cytotoxicity of the studied resin cement materials, therefore compromising their clinical performance. PMID:21625748

Effect of different resin luting cements on the marginal fit of lithium disilicate pressed crowns.

PubMed

Mounajjed, Radek; Salinas, Thomas J; Ingr, Tomas; Azar, Basel

2017-11-15

The vertical marginal discrepancy of restorations can increase upon cementation, and poor marginal fit can lead to cement dissolution, marginal discoloration, microleakage, and secondary caries. The amount of increase is related to the type of luting cement used, but how lithium disilicate pressed crowns are affected by different resin cements is unclear. The purpose of this in vitro study was to compare the effect of using different resin luting cements on the vertical marginal discrepancy of lithium disilicate pressed crowns. A total of 18 intact extracted mandibular third molars were disinfected in a solution of 10% formalin for 7 days and were then prepared to receive a ceramic crown. Impressions were made with polyvinyl siloxane and lithium disilicate pressed crowns made and cemented with 1 of 3 resin luting cements. The marginal discrepancy was measured at 4 points on the finishing line of each tooth, with optical microscopy at ×200 magnification before and after cementation. Statistical analysis was done with the Kruskal-Wallis test to compare the median marginal increase among the 3 groups. The least amount of marginal increase after cementation was with Harvard PremiumFlow cement, with an average marginal increase of 42 ±11 μm. RelyX Ultimate cement increased the margins by an average 45 ±29 μm. The highest marginal increase was found in the Enamel Plus HRi preheated composite resin group (116 ±47 μm). The marginal increase of pressed crowns cemented with preheated composite resin (Enamel Plus HRi) exceeded the clinically acceptable range of marginal discrepancy. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Colour stability and opacity of resin cements and flowable composites for ceramic veneer luting after accelerated ageing.

PubMed

Archegas, Lucí Regina Panka; Freire, Andrea; Vieira, Sergio; Caldas, Danilo Biazzetto de Menezes; Souza, Evelise Machado

2011-11-01

Colour changes of the luting material can become clinically visible affecting the aesthetic appearance of thin ceramic laminates. The aim of this in vitro study was to evaluate the colour stability and opacity of light- and dual-cured resin cements and flowable composites after accelerated ageing. The luting agents were bonded (0.2 mm thick) to ceramic disks (0.75 mm thick) built with the pressed-ceramic IPS Aesthetic Empress (n=7). Colour measurements were determined using a FTIR spectrophotometer before and after accelerated ageing in a weathering machine with a total energy of 150 kJ. Changes in colour (ΔE) and opacity (ΔO) were obtained using the CIE L*a*b* system. The results were submitted to one-way ANOVA, Tukey HSD test and Student's t test (α=5%). All the materials showed significant changes in colour and opacity. The ΔE of the materials ranged from 0.41 to 2.40. The highest colour changes were attributed to RelyX ARC and AllCem, whilst lower changes were found in Variolink Veneer, Tetric Flow and Filtek Z350 Flow. The opacity of the materials ranged from -0.01 to 1.16 and its variation was not significant only for Opallis Flow and RelyX ARC. The accelerated ageing led to colour changes in all the evaluated materials, although they were considered clinically acceptable (ΔE<3). Amongst the dual-cured resin cements, Variolink II demonstrated the highest colour stability. All the flowable composites showed proper colour stability for the luting of ceramic veneers. After ageing, an increase in opacity was observed for most of the materials. Copyright © 2011 Elsevier Ltd. All rights reserved.

The effect of polymerization mode on monomer conversion, free radical entrapment, and interaction with hydroxyapatite of commercial self-adhesive cements.

PubMed

D'Alpino, Paulo Henrique Perlatti; Silva, Marília Santos; Vismara, Marcus Vinícius Gonçalves; Di Hipólito, Vinicius; Miranda González, Alejandra Hortencia; de Oliveira Graeff, Carlos Frederico

2015-06-01

This study evaluated the degree of conversion, the free radical entrapment, and the chemical interaction of self-adhesive resin cements mixed with pure hydroxyapatite, as a function of the polymerization activation mode among a variety of commercial self-adhesive cements. Four cements (Embrace WetBond, MaxCem Elite, Bifix SE, and RelyX U200) were mixed, combined with hydroxyapatite, dispensed into molds, and distributed into three groups, according to polymerization protocols: IP (photoactivation for 40s); DP (delayed photoactivation, 10 min self-curing plus 40s light-activated); and CA (chemical activation, no light exposure). Infrared (IR) spectra were obtained and monomer conversion (%) was calculated by comparing the aliphatic-to-aromatic IR absorption peak ratio before and after polymerization (n=10). The free radical entrapment values of the resin cements were characterized using Electron Paramagnetic Resonance (EPR) and the concentration of spins (number of spins/mass) calculated (n=3). Values were compared using two-way ANOVA and Tukey's post-hoc test (α=5%). X-ray diffraction (XRD) characterized the crystallinity of hydroxyapatite as a function of the chemical interactions with the resin cements. The tested parameters varied as a function of resin cement and polymerization protocol. Embrace WetBond and RelyX U200 demonstrated dependence on photoactivation (immediate or delayed), whereas MaxCem Elite exhibited dependence on the chemical activation mode. Bifix SE presented the best balance based on the parameters analyzed, irrespective of the activation protocol. Choice of polymerization protocol affects the degree of conversion, free radical entrapment, and the chemical interaction between hydroxyapatite and self-adhesive resin cement mixtures. Copyright © 2015 Elsevier Ltd. All rights reserved.

A castor oil-containing dental luting agent: effects of cyclic loading and storage time on flexural strength

PubMed Central

DERCELI, Juliana dos Reis; FAIS, Laiza Maria Grassi; PINELLI, Lígia Antunes Pereira

2014-01-01

Favorable results in the use of castor oil polyurethane (COP) as pulp capping, membrane material, sealer, mouthwash and in bone repair, associated with the fact that Ricinus communis is not derived from petroleum and it is abundant in Brazil, encourage researches in the development of luting agents. Objectives This study compared the flexural strength (FS) of a castor oil-containing dental luting agent with a weight percentage of 10% (wt%) of calcium carbonate (COP10) with RelyX ARC (RX) after mechanical cycling (MC) and distilled water storage. Material and Methods Sixty-four specimens (25x2x2 mm) were fabricated and divided into two groups, COP10 and RX (control). Each group was divided into 4 subgroups (n=8) according to the storage time, 24 hours (24 h) or 60 days (60 d), and the performance (MC+FS) or not (only FS) of the mechanical cycling test. The FS (10 kN; 0.5 mm/min) and MC tests (10,000 cycles, 5 Hz, 0.5 mm/min) were carried out using an MTS-810 machine. The data were analyzed using ANOVA (α=0.05). Results The obtained FS (MPa) values were: COP10 24h- 19.04±2.41; COP10 60d- 17.92±3.54; RX 24h- 75.19±3.43; RX 60d- 88.77±6.89. All the RX specimens submitted to MC fractured, while the values for COP10 after MC were as follows: COP10 24h- 17.90±1.87 and COP10 60d- 18.60±1.60. Conclusions A castor oil-containing dental luting agent with a weight percentage of 10% (wt%) of calcium carbonate is resistant to mechanical cycling without decreases in flexural strength. However, mean COP10 showed only about 25% of the RelyX ARC mean flexural strength. PMID:25591018

Cytotoxicity Evaluation of Self Adhesive Composite Resin Cements by Dentin Barrier Test on 3D Pulp Cells.

PubMed

Ulker, Hayriye Esra; Sengun, Abdulkadir

2009-04-01

The aim of this study was to evaluate the effects of five self-etch dental composite resin cements on the cell viability of bovine dental papilla-derived cells. The cytotoxicity of composite resin cements (Rely X Unicem Clicker, 3M ESPE; MaxCem; KERR, Panavia F 2.0; Kuraray, BisCem; Bisco and Bistite II DC; Tokuyama) was analyzed in a dentin barrier test device using three-dimensional (3D) pulp cell cultures. A commercially available cell culture perfusion chamber was separated into two compartments by 500 mum dentin disc. The three dimensional cultures placed on a dentin disk held in place by a special biocompatible stainless-steel holder. Test materials were introduced into the upper compartment in direct contact with the cavity side of the dentin disks according to the manufacturer's instructions. Subsequently, the pulpal part of the perfusion chamber containing the cell cultures was perfused with medium (2 ml/h). After an exposure period of 24 h, the cell survival was determined by the MTT assay. Statistical analyses were performed using the Mann-Whitney U-test. In dentin barrier test, cell survival was similar with Maxcem and negative control group (P>.05), and all other tested materials were cytotoxic for the three dimensional cell cultures (P>.05). The significance of composite resin cements is being more important in dentistry. The cytotoxic potencies demonstrated by these materials might be of clinical relevance. Some composite resin cements include biologically active ingredients and may modify pulp cell metabolism when the materials are used in deep cavities or directly contact pulp tissue.

Simplified cementation of lithium disilicate crowns: Retention with various adhesive resin cement combinations.

PubMed

Johnson, Glen H; Lepe, Xavier; Patterson, Amanda; Schäfer, Oliver

2017-09-27

A composite resin cement and matching self-etch adhesive was developed to simplify the dependable retention of lithium disilicate crowns. The efficacy of this new system is unknown. The purpose of this in vitro study was to determine whether lithium disilicate crowns cemented with a new composite resin and adhesive system and 2 other popular systems provide clinically acceptable crown retention after long-term aging with monthly thermocycling. Extracted human molars were prepared with a flat occlusal surface, 20-degree convergence, and 4 mm axial length. The axio-occlusal line angle was slightly rounded. The preparation surface area was determined by optical scanning and the analysis of the standard tessellation language (STL) files. The specimens were distributed into 3 cement groups (n=12) to obtain equal mean surface areas. Lithium disilicate crowns (IPS e.max Press) were fabricated for each preparation, etched with 9.5% hydrofluoric acid for 15 seconds, and cleaned. Cement systems were RelyX Ultimate with Scotch Bond Universal (3M Dental Products); Monobond S, Multilink Automix with Multilink Primer A and B (Ivoclar Vivadent AG); and NX3 Nexus with OptiBond XTR (Kerr Corp). Each adhesive provided self-etching of the dentin. Before cementation, the prepared specimens were stored in 35°C water. A force of 196 N was used to cement the crowns, and the specimens were polymerized in a 35°C oven at 100% humidity. After 24 hours of storage at 100% humidity, the cemented crowns were thermocycled (5°C to 55°C) for 5000 cycles each month for 6 months. The crowns were removed axially at 0.5 mm/min. The removal force was recorded and the dislodgement stress calculated using the preparation surface area. The type of cement failure was recorded, and the data were analyzed by 1-way ANOVA and the chi-square test (α=.05) after the equality of variances had been assessed with the Levene test. The Levene test was nonsignificant (P=.936). The ANOVA revealed the mean removal stresses, and forces did not differ for RelyX Ultimate with Scotchbond Universal (3.9 MPa; 522 N) and Multilink Automix with Multilink Primer (3.7 MPa; 511 N); both differed significantly (P=.022) from the mean for NX3 Nexus with OptiBond XTR (2.9 MPa; 387 N). For all 3 cements, the modes of failure showed cement principally on the crown intaglio, and the chi-square analysis was nonsignificant (P=.601). IPS e.max Press (lithium disilicate) crowns were well retained (2.9-3.9 MPa; 387-522 N) by the 3 cement-adhesive combinations after 6 months of aging with monthly thermocycling. These results can serve as a basis for cement selection for this type of crown because the values significantly exceeded those for zinc phosphate. Cements using their matched dentin bonding agent as the ceramic primer were as successful as cements with a separate silane coupling agent. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Comparison of temperature change among different adhesive resin cement during polymerization process.

PubMed

Alkurt, Murat; Duymus, Zeynep Yesil; Gundogdu, Mustafa; Karadas, Muhammet

2017-01-01

The aim of this study was to assess the intra-pulpal temperature changes in adhesive resin cements during polymerization. Dentin surface was prepared with extracted human mandibular third molars. Adhesive resin cements (Panavia F 2.0, Panavia SA, and RelyX U200) were applied to the dentin surface and polymerized under IPS e.max Press restoration. K-type thermocouple wire was positioned in the pulpal chamber to measure temperature change ( n = 7). The temperature data were recorded (0.0001 sensible) and stored on a computer every 0.1 second for sixteen minutes. Differences between the baseline temperature and temperatures of various time points (2, 4, 6, 8, 10, 12, 14, and 16 minute) were determined and mean temperature changes were calculated. At various time intervals, the differences in temperature values among the adhesive resin cements were analyzed by two-way ANOVA and post-hoc Tukey honestly test (α = 0.05). Significant differences were found among the time points and resin cements ( P < 0.05). Temperature values of the Pan SA group were significantly higher than Pan F and RelyX ( P < 0.05). Result of the study on self-adhesive and self-etch adhesive resin cements exhibited a safety intra-pulpal temperature change.

Cusp Fracture Resistance of Maxillary Premolars Restored with the Bonded Amalgam Technique Using Various Luting Agents

PubMed Central

Marchan, Shivaughn M.; Coldero, Larry; White, Daniel; Smith, William A. J.; Rafeek, Reisha N.

2009-01-01

Objective. This in vitro study uses measurements of fracture resistance to compare maxillary premolars restored with the bonded amalgam technique using a new resin luting cement, glass ionomer, and resin-modified glass ionomer as the bonding agents. Materials. Eighty-five sound maxillary premolars were selected and randomly assigned to one of five test groups of 17 teeth each. One group of intact teeth served as the control. The remaining groups were prepared to a standard cavity form relative to the dimensions of the overall tooth and restored with amalgam alone or a bonded amalgam using one of three luting agents: RelyX Arc (a new resin luting cement), RelyX luting (a resin-modified glass ionomer), or Ketac-Cem μ (a glass ionomer) as the bonding agents. Each tooth was then subjected to compressive testing until catastrophic failure occurred. The mean loads at failure of each group were statistically compared using ANOVA with a post hoc Bonferroni test. Results. It was found that regardless of the luting cement used for the amalgam bonding technique, there was little effect on the fracture resistance of teeth. Conclusion. Cusp fracture resistance of premolars prepared with conservative MOD cavity preparations is not improved by using an amalgam-bonding technique compared to similar cavities restored with amalgam alone. PMID:20339450

In Vitro Retentive Effect of Groove, Sandblasting, and Cement Type on Stainless Steel Crowns in Primary Molars.

PubMed

Pathak, Sidhant; Shashibhushan, K K; Bharath, K P; Poornima, P; Reddy, V V Subba

2015-01-01

The purpose of this study was to evaluate and compare the effect of placing vertical grooves, sandblasting, and luting cements on the retention of stainless steel crowns (SSCs). Eighty extracted primary molars were mounted in acrylic blocks. Specimens were divided into Group 1 (RelyX U200) and Group 2 (Smart Cem2). Teeth in each group were further subdivided into Subgroup A (no vertical grooves and no sandblasting), Subgroup B (vertical grooves), Subgroup C (sandblasting of crowns), and Subgroup D (vertical grooves and sandblasting of crowns). After cementation, SSCs were pulled off using a universal testing machine. One-way analysis of variance was used for statistical analyses. In Groups 1 and 2, the highest retentive strengths were found in Subgroup D (1,124 and 783 kPa, respectively), followed by Subgroup C (1,066 and 748 kPa, respectively), Subgroup A (762 and 356 kPa, respectively), and Subgroup B (743 and 314 kPa, respectively). Retentive strength in Group one was significantly higher than in Group two; Subgroups A and B were significantly lower than C and D. RelyX U200 showed higher retentive strength than Smart Cem2. Sandblasting increased the retention strength, whereas a vertical groove had no significant effect on retention.

Effect of Anatomical Customization of the Fiber Post on the Bond Strength of a Self-Adhesive Resin Cement.

PubMed

Rocha, Adricyla Teixeira; Gonçalves, Leticia Machado; Vasconcelos, Ana Júlia de Carvalho; Matos Maia Filho, Etevaldo; Nunes Carvalho, Ceci; De Jesus Tavarez, Rudys Rodolfo

2017-01-01

The aim of the study was to evaluate, by means of the push-out test, the effect of the anatomical customization of the fiber post on the bond strength of a self-adhesive resin cement. Twelve endodontically treated, human, upper central incisors were randomly divided into two groups ( n = 6): control (glass fiber posts cemented with Relyx® U200) and customized (glass fiber posts anatomically customized with translucent composite resin cemented with Relyx U200). The roots were sectioned into three slices, cervical, middle, and apical, and photographed with a digital camera attached to a stereomicroscopic loupe. The images were analyzed by software, for evaluation of the cement line. The slices were subsequently submitted to the push-out test until the post had completely extruded, and the fracture mode was analyzed with a stereomicroscopic loupe. The results showed significant differences between the groups in the different root thirds in relation to the area occupied by air bubbles ( p < 0.05). Bond strength, when all the thirds are considered, was 8.77 ± 4.89 MPa for the control group and 16.96 ± 4.85 MPa for the customized group. The customized group showed greater bond resistance than the control group and a more uniform cement layer.

In Vitro Comparative Analysis of Fracture Resistance in Inlay Restoration Prepared with CAD-CAM and Different Systems in the Primary Teeth

PubMed Central

Derelioglu, Sera

2016-01-01

Objective. The aim of this study was to compare to fracture resistance test of inlay restorations prepared using direct inlay technique (Gradia® Direct Composite) and Indirect Restoration System® (Gradia Indirect Composite) and CAD/CAD system (Vita Enamic® Block). Study Design. 48 noncarious extracted maxillary second primary molars were randomly divided into 4 groups with 12 in each group. All the teeth were prepared based on inlay class II preparations except for the control group. Other groups were restored with Gradia Direct Composite, Gradia Indirect Composite, and Vita Enamic Block, respectively. All restorations were cemented self-adhesive dual cure resin (3M Espe, RelyX™ Unicem Aplicap). A fracture test was performed using a compressive load. Results were analyzed using one-way analysis of variance and Duncan's post hoc multiple comparison tests (α = 0.05). Results. Vita Enamic Block and Gradia Indirect Composite showed significantly higher fracture resistance than Gradia Direct Composite (p < 0.05). There was no significant difference fracture resistance between Vita Enamic Block and Gradia Indirect Composite (p > 0.05). All restorations tested led to a significant reduction in fracture resistance (p < 0.05). Conclusion. In inlay restorations, Indirect Restoration Systems and CAD/CAM systems were applied successfully together with the self-adhesive dual cure resin cements in primary molars. PMID:27830145

An in vitro radiographic analysis of the density of dental luting cements as measured by CCD-based digital radiography.

PubMed

Antonijevic, Djordje; Jevremovic, Danimir; Jovanovic, Svetlana; Obradovic-Djuricic, Kosovka

2012-05-01

According to the ISO, the radiopacity of luting cements should be equal to or greater than that of aluminum. The aim of this in vitro study was to determine the radiopacity of 13 commercially available dental luting cements and compare them with human enamel and dentin. Five classes of luting cements were evaluated: zinc phosphate (Cegal N and Harvard Zinc Phosphate), zinc polycarboxylate (Harvard Polycarboxylate and Hoffmann's Carboxylate), glass ionomers (Ketac Cem Easymix, Ketac Cem Radiopaque, and Fuji I), resin-modified glass ionomer (Rely X Luting), and resin cements (Multilink Automix, Variolink II, Speed CEM, Rely X Unicem Automix, and three shades of Variolink Veneer). Tooth slices served as controls. Five specimens of each material measuring 8 mm in diameter and 1 mm thick were prepared and radiographed alongside tooth slices and an aluminum stepwedge using a Trophy RVG sensor. The radiopacity values were expressed in mm Al and analyzed by the ANOVA and Tukey tests (P < .05). All the cements examined except Variolink Veneer had significantly higher radiopacities than that of dentin. Rely X Unicem Automix, glass ionomer, and resin-modified glass-ionomer cements demonstrated radiopacities that were not significantly different with respect to enamel. Zinc phosphate, zinc polycarboxylate, and three of the resin cements presented radiopacity values that were significantly greater than that of enamel. Almost all the investigated materials presented an acceptable radiopacity. Radiopacity of dental cements seems to depend more on the presence of elements with high atomic numbers than on the type of the material.

Effect of Anatomical Customization of the Fiber Post on the Bond Strength of a Self-Adhesive Resin Cement

PubMed Central

Rocha, Adricyla Teixeira; Vasconcelos, Ana Júlia de Carvalho; Nunes Carvalho, Ceci

2017-01-01

Aim The aim of the study was to evaluate, by means of the push-out test, the effect of the anatomical customization of the fiber post on the bond strength of a self-adhesive resin cement. Methods Twelve endodontically treated, human, upper central incisors were randomly divided into two groups (n = 6): control (glass fiber posts cemented with Relyx® U200) and customized (glass fiber posts anatomically customized with translucent composite resin cemented with Relyx U200). The roots were sectioned into three slices, cervical, middle, and apical, and photographed with a digital camera attached to a stereomicroscopic loupe. The images were analyzed by software, for evaluation of the cement line. The slices were subsequently submitted to the push-out test until the post had completely extruded, and the fracture mode was analyzed with a stereomicroscopic loupe. Results The results showed significant differences between the groups in the different root thirds in relation to the area occupied by air bubbles (p < 0.05). Bond strength, when all the thirds are considered, was 8.77 ± 4.89 MPa for the control group and 16.96 ± 4.85 MPa for the customized group. Conclusion The customized group showed greater bond resistance than the control group and a more uniform cement layer. PMID:28785281

Titanium dioxide nanotubes addition to self-adhesive resin cement: Effect on physical and biological properties.

PubMed

Ramos-Tonello, Carla M; Lisboa-Filho, Paulo N; Arruda, Larisa B; Tokuhara, Cintia K; Oliveira, Rodrigo C; Furuse, Adilson Y; Rubo, José H; Borges, Ana Flávia S

2017-07-01

This study has investigated the influence of Titanium dioxide nanotubes (TiO 2 -nt) addition to self-adhesive resin cement on the degree of conversion, water sorption, and water solubility, mechanical and biological properties. A commercially available auto-adhesive resin cement (RelyX U200™, 3M ESPE) was reinforced with varying amounts of nanotubes (0.3, 0.6, 0.9wt%) and evaluated at different curing modes (self- and dual cure). The DC in different times (3, 6, 9, 12 and 15min), water sorption (Ws) and solubility (Sl), 3-point flexural strength (σf), elastic modulus (E), Knoop microhardness (H) and viability of NIH/3T3 fibroblasts were performed to characterize the resin cement. Reinforced self-adhesive resin cement, regardless of concentration, increased the DC for the self- and dual-curing modes at all times studied. The concentration of the TiO 2 -nt and the curing mode did not influence the Ws and Sl. Regarding σf, concentrations of both 0.3 and 0.9wt% for self-curing mode resulted in data similar to that of dual-curing unreinforced cement. The E increased with the addition of 0.9wt% for self-cure mode and H increased with 0.6 and 0.9wt% for both curing modes. Cytotoxicity assays revealed that reinforced cements were biocompatible. TiO 2 -nt reinforced self-adhesive resin cement are promising materials for use in indirect dental restorations. Taken together, self-adhesive resin cement reinforced with TiO 2 -nt exhibited physicochemical and mechanical properties superior to those of unreinforced cements, without compromising their cellular viability. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Influence of matrix metalloproteinase synthetic inhibitors on dentin microtensile bond strength of resin cements.

PubMed

Stape, T H S; Menezes, M S; Barreto, B C F; Aguiar, F H B; Martins, L R; Quagliatto, P S

2012-01-01

This study evaluated the effect of dentin pretreatment with 2% chlorhexidine (CHX) or 24% ethylenediamine tetra-acetic acid gel (EDTA) on the dentin microtensile bond strength (μTBS) of resin cements. Composite blocks were luted to superficial noncarious human dentin (n=10) using two resin cements (RelyX ARC [ARC] and RelyX U100 [U100]) and three dentin pretreatments (without pretreatment-control, CHX, and EDTA). CHX was applied for 60 seconds on the acid-etched dentin in the ARC/CHX group, and for the same time on smear layer-covered dentin in the U100/CHX group. EDTA was applied for 45 seconds on smear-covered dentin in the U100/EDTA group, and it replaced phosphoric acid conditioning in the ARC/EDTA group for 60 seconds. After storage in water for 24 hours, specimens were prepared for microtensile bond strength testing. The results were submitted to two-way analysis of variance (ANOVA) followed by Tukey test. ARC produced significantly higher μTBS (p<0.05) compared to the U100, except when EDTA was used. For ARC, no pretreatment and CHX produced higher μTBS than EDTA. For U100, EDTA produced higher μTBS; no statistical difference occurred between CHX pretreatment and when no pretreatment was performed. While CHX did not affect immediate dentin bond strength of both cements, EDTA improved bond strength of U100, but it reduced dentin bond strength of ARC.

Characterization of Cement Particles Found in Peri-implantitis-Affected Human Biopsy Specimens.

PubMed

Burbano, Maria; Wilson, Thomas G; Valderrama, Pilar; Blansett, Jonathan; Wadhwani, Chandur P K; Choudhary, Pankaj K; Rodriguez, Lucas C; Rodrigues, Danieli C

2015-01-01

Peri-implantitis is a disease characterized by soft tissue inflammation and continued loss of supporting bone, which can result in implant failure. Peri-implantitis is a multifactorial disease, and one of its triggering factors may be the presence of excess cement in the soft tissues surrounding an implant. This descriptive study evaluated the composition of foreign particles from 36 human biopsy specimens with 19 specimens selected for analysis. The biopsy specimens were obtained from soft tissues affected by peri-implantitis around cement-retained implant crowns and compared with the elemental composition of commercial luting cement. Nineteen biopsy specimens were chosen for the comparison, and five test cements (TempBond, Telio, Premier Implant Cement, Intermediate Restorative Material, and Relyx) were analyzed using scanning electron microscopy equipped with energy dispersive x-ray spectroscopy. This enabled the identification of the chemical composition of foreign particles embedded in the tissue specimens and the composition of the five cements. Statistical analysis was conducted using classification trees to pair the particles present in each specimen with the known cements. The particles in each biopsy specimen could be associated with one of the commercial cements with a level of probability ranging between .79 and 1. TempBond particles were found in one biopsy specimen, Telio particles in seven, Premier Implant Cement particles in four, Relyx particles in four, and Intermediate Restorative Material particles in three. Particles found in human soft tissue biopsy specimens around implants affected by peri-implant disease were associated with five commercially available dental cements.

Effect of Resin Bonded Luting Agents Influencing Marginal Discrepancy in All Ceramic Complete Veneer Crowns.

PubMed

Ganapathy, Dhanraj; Sathyamoorthy, Anusha; Ranganathan, Hemalatha; Murthykumar, Karthikeyan

2016-12-01

Marginal discrepancy severely affects the long term success of All ceramic complete veneer crowns. The precise role of resin luting agents influencing this phenomenon needs to be explored further. To estimate and compare the marginal discrepancy in CAD/CAM processed All ceramic complete veneer crowns prior and following luting with resin bonded luting agents. Extracted human maxillary first premolars were randomly allocated into four groups of 27 samples each Viz., Group I-Resin Modified Glass Ionomer Cement (GIC) (RelyX), Group II-Bis-GMA based dual cure resin cement (Variolink II), Group III-PMMA based resin cement (Superbond), Group IV- Urethane Dimethacrylate resin cement (Calibra). Following tooth preparation, CAD/CAM All ceramic complete veneer crowns were fabricated and sectioned and marginal discrepancy was evaluated using a scanning electron microscope (TESCAN, Magnification power-1,00,000x) prior and after luting with the experimental resin cements. The vertical and horizontal discrepancy before and after cementation with Group I [270.08±103.10μm, 165.3±53.00μm and 270.86±102.70μm, 166.62±54.96μm respectively]; Group II [254.21±79.20μm, 117.75±24.29μm and 234.81±79μm, 116.89±18.22μm respectively]; Group III [272.47±86.25μm, 142.08±50.83μm and 251.82±62.69μm, 136.07±44.95μm respectively]; Group IV were [260.28±64.81μm, 116.98±17.71μm and 233.08±69.44μm, 116.58±21.13μm respectively]. ANOVA inferred a statistically significant difference between the four test specimen with regards to vertical and horizontal marginal discrepancy after cementation (F=9.092, p<0.001), (F=10.97, p<0.001). Tukey HSD Post-hoc test observed significant differences in vertical and horizontal marginal discrepancies between the resin modified glass ionomer and resin cements (p<0.05). Resin cements exhibited a greater reduction in the marginal discrepancy than the resin modified glass ionomer following luting in All ceramic complete veneer crowns. Hence resin cements are more preferable to GIC for luting All ceramic complete veneer crowns.

Effect of Resin Bonded Luting Agents Influencing Marginal Discrepancy in All Ceramic Complete Veneer Crowns

PubMed Central

Sathyamoorthy, Anusha; Ranganathan, Hemalatha; Murthykumar, Karthikeyan

2016-01-01

Introduction Marginal discrepancy severely affects the long term success of All ceramic complete veneer crowns. The precise role of resin luting agents influencing this phenomenon needs to be explored further. Aim To estimate and compare the marginal discrepancy in CAD/CAM processed All ceramic complete veneer crowns prior and following luting with resin bonded luting agents. Materials and Methods Extracted human maxillary first premolars were randomly allocated into four groups of 27 samples each Viz., Group I-Resin Modified Glass Ionomer Cement (GIC) (RelyX), Group II-Bis-GMA based dual cure resin cement (Variolink II), Group III-PMMA based resin cement (Superbond), Group IV- Urethane Dimethacrylate resin cement (Calibra). Following tooth preparation, CAD/CAM All ceramic complete veneer crowns were fabricated and sectioned and marginal discrepancy was evaluated using a scanning electron microscope (TESCAN, Magnification power-1,00,000x) prior and after luting with the experimental resin cements. Results The vertical and horizontal discrepancy before and after cementation with Group I [270.08±103.10μm, 165.3±53.00μm and 270.86±102.70μm, 166.62±54.96μm respectively]; Group II [254.21±79.20μm, 117.75±24.29μm and 234.81±79μm, 116.89±18.22μm respectively]; Group III [272.47±86.25μm, 142.08±50.83μm and 251.82±62.69μm, 136.07±44.95μm respectively]; Group IV were [260.28±64.81μm, 116.98±17.71μm and 233.08±69.44μm, 116.58±21.13μm respectively]. ANOVA inferred a statistically significant difference between the four test specimen with regards to vertical and horizontal marginal discrepancy after cementation (F=9.092, p<0.001), (F=10.97, p<0.001). Tukey HSD Post-hoc test observed significant differences in vertical and horizontal marginal discrepancies between the resin modified glass ionomer and resin cements (p<0.05). Conclusion Resin cements exhibited a greater reduction in the marginal discrepancy than the resin modified glass ionomer following luting in All ceramic complete veneer crowns. Hence resin cements are more preferable to GIC for luting All ceramic complete veneer crowns. PMID:28209008

Longevity of bond strength of resin cements to root dentine after radiation therapy.

PubMed

Yamin, P A; Pereira, R D; Lopes, F C; Queiroz, A M; Oliveira, H F; Saquy, P C; Sousa-Neto, M D

2018-05-04

To evaluate the bond strength and adhesive interface between several resin cements and root dentine immediately and 6 months after radiotherapy. Sixty maxillary canines were selected and randomly assigned to two groups (n = 30): one group was not irradiated and the other one was subjected to a cumulative radiation dose of 60 Gy. The teeth were sectioned to obtain roots 16 mm long and the canals were prepared with the Reciproc system (R50) and filled using a lateral condensation technique with an epoxy resin sealer. Each group was divided into three subgroups (n = 10) according to the resin cement used for fibreglass fibre post cementation: RelyX-U200, Panavia-F2.0 and RelyX ARC. The posts were cemented in accordance with the manufacturer's recommendations. Three 1-mm-thick dentine slices were then obtained from each root third. The first two slices in the crown-apex direction of each third were selected for the push-out test. The failure mode after debonding was determined with a stereo microscope. The third slice from each root third was selected for scanning electron microscopy (SEM) analyses to examine the resin cement-dentine interface with 100, 1000, 2000 and 4000× magnification. Bond strength data were analysed by anova and Tukey's test (α = 0.05). Significantly lower bond strength (P < 0.0001) was obtained after irradiation compared to nonirradiated teeth. RelyX-U200 cemented fibre posts had the higher bond strength (15.17 ± 5.89) compared with RelyX ARC (P < 0.001) and Panavia-F2.0 (P < 0.001). The evaluation after 6 months revealed lower bond strength values compared to the immediate values (P < 0.001) for irradiated and nonirradiated teeth. Cohesive failures occurred in the irradiated dentine. SEM revealed fractures, microfractures and fewer collagen fibres in irradiated root dentine. RelyX-U200 and Panavia-F2.0 were associated with a juxtaposed interface of the cement with the radicular dentine in irradiated and nonirradiated teeth, and for RelyX ARC, hybrid layer formation and tags were observed in both irradiated and nonirradiated teeth. Radiation was associated with a decrease in the push-out bond strength and with lower resin cement/root dentine interface adaptation. Self-adhesive resin cement was a better alternative for fibre post cementation in teeth subjected to radiation therapy. The bond strength decreased after 6 months. © 2018 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Evaluation of self-adhesive resin cement bond strength to yttria-stabilized zirconia ceramic (Y-TZP) using four surface treatments.

PubMed

Miragaya, Luciana; Maia, Luciane Cople; Sabrosa, Carlos Eduardo; de Goes, Mário Fernando; da Silva, Eduardo Moreira

2011-10-01

To evaluate the influence of four surface treatments on the bond strength of a self-adhesive resin cement to an yttria-stabilized zirconia (Y-TZP) ceramic material (Lava Frame zirconia). Forty plates (8 x 6 x 1 mm) of a Y-TZP ceramic restorative material were randomly assigned to four groups (n = 10) according to the surface treatments: control, no treatment; airborne-particle abrasion with 50-μm Al2O3; coating with an MDP-based primer; conditioning with Rocatec System. The ceramic plates treated with each of the four methods were further divided into 2 subgroups according to the resin cement tested: RelyXTM ARC (ARC, conventional) and RelyXTM Unicem (Ucem, self-adhesive). The resin cements were put into PVC tubes (diameter 0.75 mm, 0.5 mm height) placed on the ceramic plate surfaces. After water storage at 37°C for 24 h, the specimens were submitted to a microshear bond strength (μSBS) test at a crosshead speed of 1.0 mm/min. The surface treatments significantly influenced the μSBS (p < 0.05). For the four surface treatments, UCem presented significantly higher μSBS than ARC (p < 0.05). For both resin cements, the best result was produced by the MDP-based primer: ARC 15.9 ± 5.0 MPa and UCem 36.2 ± 2.1 MPa. The highest μSBS values were presented by UCem on ceramic plates treated with the MDP-based primer (36.2 ± 2.1 MPa) and Rocatec system (37.4 ± 2.3 MPa). Irrespective of the surface treatment, the self-adhesive resin cement performed better in terms of bond strength to yttria-stabilized zirconia ceramic than did conventional resin cement.

Er:YAG laser debonding of porcelain veneers

NASA Astrophysics Data System (ADS)

Buu, Natalie; Morford, Cynthia; Finzen, Frederick; Sharma, Arun; Rechmann, Peter

2010-02-01

The removal of porcelain veneers using Er:YAG lasers has not been previously described in the scientific literature. This study was designed to systematically investigate the efficacy of an Er:YAG laser on veneer debonding without damaging the underlying tooth structure, as well as preserving a new or misplaced veneer. Initially, Fourier Transform Infrared Spectroscopy (FTIR) was used on flat porcelain veneer samples (IPS Empress Esthetic; Ivoclar Vivadent, Amherst, NY) to assess which infrared laser wavelengths are transmitted through the veneer. Additionally, FTIR spectra from a veneer bonding cement (RelyX Veneer Cement A1; 3M ESPE, St. Paul, MN) were obtained. While the veneer material showed no characteristic water absorption bands in the FTIR, the bonding cement has a broad H2O/OH absorption band coinciding with the ER:YAG laser emission wavelength. Consequently Er:YAG laser energy transmission through different veneer thicknesses was measured. The porcelain veneers transmitted 11 - 18 % of the incident Er:YAG laser energy depending on their thicknesses (Er:YAG laser: LiteTouch by Syneron; wavelength 2,940 nm, 10 Hz repetition rate, pulse duration 100 μs at 133 mJ/pulse; straight sapphire tip 1,100 μm diameter; Syneron, Yokneam, Israel). Initial signs of cement ablation occurred at approximately 1.8 - 4.0 J/cm2. This can be achieved by irradiating through the veneer with the fiber tip positioned at a distance of 3-6 mm from the veneer surface, and operating the Er:YAG laser with 133 mJ output energy. All eleven veneers bonded on extracted anterior incisor teeth were easily removed using the Er:YAG laser. The removal occurred without damaging underlying tooth structure as verified by light microscopic investigation (Incident Light Microscope Olympus B 50, Micropublisher RTV 3.3 MP, Image Pro software, Olympus). The debonding mainly occurred at the cement/veneer interface. When the samples were stored in saline solution for 5 days and/or an air-waterspray was used during irradiation, there was a high chance that the veneer would fractured during debonding. However if samples were not stored in water and only air spray was used, 75% of the veneers could be removed without any fracture. The use of an Er:YAG laser can be effective in not only debonding porcelain veneers and preserving tooth structure, but also in maintaining veneer integrity.

Effect of surface treatments on the flexural properties and adhesion of glass fiber-reinforced composite post to self-adhesive luting agent and radicular dentin.

PubMed

Elnaghy, Amr M; Elsaka, Shaymaa E

2016-01-01

This study evaluated the effect of different surface treatments on the flexural properties and adhesion of glass fiber post to self-adhesive luting agent and radicular dentin. Seventy-five single-rooted human teeth were prepared to receive a glass fiber post (Reblida). The posts were divided into five groups according to the surface treatment: Gr C (control; no treatment), Gr S (silanization for 60 s), Gr AP (airborne-particle abrasion), Gr HF (etching with 9 % hydrofluoric acid for 1 min), and Gr M10 (etching with CH2Cl2 for 10 min). Dual-cure self-adhesive luting agent (Rely X Unicem) was applied to each group for testing the adhesion using micropush-out test. Failure types were examined with stereomicroscope and surface morphology of the posts was characterized using a scanning electron microscopy (SEM). Flexural properties of posts were assessed using a three-point bending test. Data were analyzed using ANOVA and Tukey's HSD test. Statistical significance was set at the 0.05 probability level. Groups treated with M10 showed significantly higher bond strength than those obtained with other surface treatments (P < 0.05). In general, improvements in bond strength (MPa) were found in the following order: M10 > C > S > AP > HF. Most failure modes were adhesive type of failures between dentin and luting agent (48.2%). SEM analysis revealed that the fiber post surfaces were modified after surface treatments. The surface treatments did not compromise the flexural properties of fiber posts. Application of M10 to the fiber post surfaces enhanced the adhesion to self-adhesive luting agent and radicular dentin.

Influence of different luting protocols on shear bond strength of computer aided design/computer aided manufacturing resin nanoceramic material to dentin

PubMed Central

Poggio, Claudio; Pigozzo, Marco; Ceci, Matteo; Scribante, Andrea; Beltrami, Riccardo; Chiesa, Marco

2016-01-01

Background: The purpose of this study was to evaluate the influence of three different luting protocols on shear bond strength of computer aided design/computer aided manufacturing (CAD/CAM) resin nanoceramic (RNC) material to dentin. Materials and Methods: In this in vitro study, 30 disks were milled from RNC blocks (Lava Ultimate/3M ESPE) with CAD/CAM technology. The disks were subsequently cemented to the exposed dentin of 30 recently extracted bovine permanent mandibular incisors. The specimens were randomly assigned into 3 groups of 10 teeth each. In Group 1, disks were cemented using a total-etch protocol (Scotchbond™ Universal Etchant phosphoric acid + Scotchbond Universal Adhesive + RelyX™ Ultimate conventional resin cement); in Group 2, disks were cemented using a self-etch protocol (Scotchbond Universal Adhesive + RelyX™ Ultimate conventional resin cement); in Group 3, disks were cemented using a self-adhesive protocol (RelyX™ Unicem 2 Automix self-adhesive resin cement). All cemented specimens were placed in a universal testing machine (Instron Universal Testing Machine 3343) and submitted to a shear bond strength test to check the strength of adhesion between the two substrates, dentin, and RNC disks. Specimens were stressed at a crosshead speed of 1 mm/min. Data were analyzed with analysis of variance and post-hoc Tukey's test at a level of significance of 0.05. Results: Post-hoc Tukey testing showed that the highest shear strength values (P < 0.001) were reported in Group 2. The lowest data (P < 0.001) were recorded in Group 3. Conclusion: Within the limitations of this in vitro study, conventional resin cements (coupled with etch and rinse or self-etch adhesives) showed better shear strength values compared to self-adhesive resin cements. Furthermore, conventional resin cements used together with a self-etch adhesive reported the highest values of adhesion. PMID:27076822

Influence of different luting protocols on shear bond strength of computer aided design/computer aided manufacturing resin nanoceramic material to dentin.

PubMed

Poggio, Claudio; Pigozzo, Marco; Ceci, Matteo; Scribante, Andrea; Beltrami, Riccardo; Chiesa, Marco

2016-01-01

The purpose of this study was to evaluate the influence of three different luting protocols on shear bond strength of computer aided design/computer aided manufacturing (CAD/CAM) resin nanoceramic (RNC) material to dentin. In this in vitro study, 30 disks were milled from RNC blocks (Lava Ultimate/3M ESPE) with CAD/CAM technology. The disks were subsequently cemented to the exposed dentin of 30 recently extracted bovine permanent mandibular incisors. The specimens were randomly assigned into 3 groups of 10 teeth each. In Group 1, disks were cemented using a total-etch protocol (Scotchbond™ Universal Etchant phosphoric acid + Scotchbond Universal Adhesive + RelyX™ Ultimate conventional resin cement); in Group 2, disks were cemented using a self-etch protocol (Scotchbond Universal Adhesive + RelyX™ Ultimate conventional resin cement); in Group 3, disks were cemented using a self-adhesive protocol (RelyX™ Unicem 2 Automix self-adhesive resin cement). All cemented specimens were placed in a universal testing machine (Instron Universal Testing Machine 3343) and submitted to a shear bond strength test to check the strength of adhesion between the two substrates, dentin, and RNC disks. Specimens were stressed at a crosshead speed of 1 mm/min. Data were analyzed with analysis of variance and post-hoc Tukey's test at a level of significance of 0.05. Post-hoc Tukey testing showed that the highest shear strength values (P < 0.001) were reported in Group 2. The lowest data (P < 0.001) were recorded in Group 3. Within the limitations of this in vitro study, conventional resin cements (coupled with etch and rinse or self-etch adhesives) showed better shear strength values compared to self-adhesive resin cements. Furthermore, conventional resin cements used together with a self-etch adhesive reported the highest values of adhesion.

Marginal Fit of Metal-Ceramic Copings: Effect of Luting Cements and Tooth Preparation Design.

PubMed

de Almeida, Juliana Gomes Dos Santos Paes; Guedes, Carlos Gramani; Abi-Rached, Filipe de Oliveira; Trindade, Flávia Zardo; Fonseca, Renata Garcia

2017-12-22

To evaluate the effect of the triad finish line design, axial wall convergence angle, and luting cement on the marginal fit of metal copings used in metal-ceramic crowns. Schematic dies and their respective copings were cast in NiCr alloy. The dies exhibited the following finish line/convergence angle combinations: sloping shoulder/6°, sloping shoulder/20°, shoulder/6°, shoulder/20°. Marginal fit was evaluated under a stereomicroscope, before and after cementation. Copings were air-abraded with 50 μm Al 2 O 3 particles and cemented with Cimento de Zinco, RelyX U100, or Panavia F cements (n = 10/group). Data were square-root transformed and analyzed by 3-way factorial random effect model and Tukey's post hoc test (α = 0.05). Statistical analysis showed significance for the interactions finish line and convergence angle (p < 0.05), convergence angle and time (p < 0.001), and luting cement and time (p < 0.001). Sloping shoulder/20° provided the highest marginal discrepancy when compared to the other finish line/convergence angle combinations, which were statistically similar among each other. For both convergence angles and for all luting cements, the marginal discrepancy was significantly higher after cementation. Before and after cementation, 6° provided better marginal fit than 20°. After cementation, Panavia F provided higher marginal discrepancy than Cimento de Zinco. Lower convergence angle combined with shoulder and a low-consistency luting cement is preferable to cement metal copings. © 2017 by the American College of Prosthodontists.

Thio-urethanes improve properties of dual-cured composite cements.

PubMed

Bacchi, A; Dobson, A; Ferracane, J L; Consani, R; Pfeifer, C S

2014-12-01

This study aims at modifying dual-cure composite cements by adding thio-urethane oligomers to improve mechanical properties, especially fracture toughness, and reduce polymerization stress. Thiol-functionalized oligomers were synthesized by combining 1,3-bis(1-isocyanato-1-methylethyl)benzene with trimethylol-tris-3-mercaptopropionate, at 1:2 isocyanate:thiol. Oligomer was added at 0, 10 or 20 wt% to BisGMA-UDMA-TEGDMA (5:3:2, with 25 wt% silanated inorganic fillers) or to one commercial composite cement (Relyx Ultimate, 3M Espe). Near-IR was used to measure methacrylate conversion after photoactivation (700 mW/cm(2) × 60s) and after 72 h. Flexural strength and modulus, toughness, and fracture toughness were evaluated in three-point bending. Polymerization stress was measured with the Bioman. The microtensile bond strength of an indirect composite and a glass ceramic to dentin was also evaluated. Results were analyzed with analysis of variance and Tukey's test (α = 0.05). For BisGMA-UDMA-TEGDMA cements, conversion values were not affected by the addition of thio-urethanes. Flexural strength/modulus increased significantly for both oligomer concentrations, with a 3-fold increase in toughness at 20 wt%. Fracture toughness increased over 2-fold for the thio-urethane modified groups. Contraction stress was reduced by 40% to 50% with the addition of thio-urethanes. The addition of thio-urethane to the commercial cement led to similar flexural strength, toughness, and conversion at 72h compared to the control. Flexural modulus decreased for the 20 wt% group, due to the dilution of the overall filler volume, which also led to decreased stress. However, fracture toughness increased by up to 50%. The microtensile bond strength increased for the experimental composite cement with 20 wt% thio-urethane bonding for both an indirect composite and a glass ceramic. Novel dual-cured composite cements containing thio-urethanes showed increased toughness, fracture toughness and bond strength to dentin while demonstrating reduced contraction stress. All of these benefits are derived without compromising the methacrylate conversion of the resin component. The modification does not require changing the operatory technique. © International & American Associations for Dental Research.

Thio-urethanes Improve Properties of Dual-cured Composite Cements

PubMed Central

Bacchi, A.; Dobson, A.; Ferracane, J.L.; Consani, R.; Pfeifer, C.S.

2014-01-01

This study aims at modifying dual-cure composite cements by adding thio-urethane oligomers to improve mechanical properties, especially fracture toughness, and reduce polymerization stress. Thiol-functionalized oligomers were synthesized by combining 1,3-bis(1-isocyanato-1-methylethyl)benzene with trimethylol-tris-3-mercaptopropionate, at 1:2 isocyanate:thiol. Oligomer was added at 0, 10 or 20 wt% to BisGMA-UDMA-TEGDMA (5:3:2, with 25 wt% silanated inorganic fillers) or to one commercial composite cement (Relyx Ultimate, 3M Espe). Near-IR was used to measure methacrylate conversion after photoactivation (700 mW/cm2 × 60s) and after 72 h. Flexural strength and modulus, toughness, and fracture toughness were evaluated in three-point bending. Polymerization stress was measured with the Bioman. The microtensile bond strength of an indirect composite and a glass ceramic to dentin was also evaluated. Results were analyzed with analysis of variance and Tukey’s test (α = 0.05). For BisGMA-UDMA-TEGDMA cements, conversion values were not affected by the addition of thio-urethanes. Flexural strength/modulus increased significantly for both oligomer concentrations, with a 3-fold increase in toughness at 20 wt%. Fracture toughness increased over 2-fold for the thio-urethane modified groups. Contraction stress was reduced by 40% to 50% with the addition of thio-urethanes. The addition of thio-urethane to the commercial cement led to similar flexural strength, toughness, and conversion at 72h compared to the control. Flexural modulus decreased for the 20 wt% group, due to the dilution of the overall filler volume, which also led to decreased stress. However, fracture toughness increased by up to 50%. The microtensile bond strength increased for the experimental composite cement with 20 wt% thio-urethane bonding for both an indirect composite and a glass ceramic. Novel dual-cured composite cements containing thio-urethanes showed increased toughness, fracture toughness and bond strength to dentin while demonstrating reduced contraction stress. All of these benefits are derived without compromising the methacrylate conversion of the resin component. The modification does not require changing the operatory technique. PMID:25248610

Push-out bond strength of fiber posts to root dentin using glass ionomer and resin modified glass ionomer cements.

PubMed

Pereira, Jefferson Ricardo; Rosa, Ricardo Abreu da; Só, Marcus Vinícius Reis; Afonso, Daniele; Kuga, Milton Carlos; Honório, Heitor Marques; Valle, Accácio Lins do; Vidotti, Hugo Alberto

2014-01-01

The purpose of this study was to assess the push-out bond strength of glass fiber posts to root dentin after cementation with glass ionomer (GICs) and resinmodified glass ionomer cements (RMGICs). Fifty human maxillary canines were transversally sectioned at 15 mm from the apex. Canals were prepared with a step back technique until the application of a #55 K-file and filled. Post spaces were prepared and specimens were divided into five groups according to the cement used for post cementation: Luting & Lining Cement; Fuji II LC Improved; RelyX Luting; Ketac Cem; and Ionoseal. After cementation of the glass fiber posts, all roots were stored at 100% humidity until testing. For push-out test, 1-mm thick slices were produced. The push-out test was performed in a universal testing machine at a crosshead speed of 0.5 mm/minute and the values (MPa) were analyzed by Kolmogorov-Smirnov and Levene's tests and by two-way ANOVA and Tukey's post hoc test at a significance level of 5%. Fiber posts cemented using Luting & Lining Cement, Fuji II LC Improved, and Ketac Cem presented the highest bond strength to root dentin, followed by RelyX Luting. Ionoseal presented the lowest bond strength values (P>0.05). The post level did not influence the bond strength of fiber posts to root dentin (P=0.148). The major cause of failure was cohesive at the cement for all GICs and RMGICs. Except for Ionoseal, all cements provided satisfactory bond strength values.

Push-out bond strength of fiber posts to root dentin using glass ionomer and resin modified glass ionomer cements

PubMed Central

PEREIRA, Jefferson Ricardo; da ROSA, Ricardo Abreu; SÓ, Marcus Vinícius Reis; AFONSO, Daniele; KUGA, Milton Carlos; HONÓRIO, Heitor Marques; do VALLE, Accácio Lins; VIDOTTI, Hugo Alberto

2014-01-01

Objective The purpose of this study was to assess the push-out bond strength of glass fiber posts to root dentin after cementation with glass ionomer (GICs) and resin-modified glass ionomer cements (RMGICs). Material and Methods Fifty human maxillary canines were transversally sectioned at 15 mm from the apex. Canals were prepared with a step back technique until the application of a #55 K-file and filled. Post spaces were prepared and specimens were divided into five groups according to the cement used for post cementation: Luting & Lining Cement; Fuji II LC Improved; RelyX Luting; Ketac Cem; and Ionoseal. After cementation of the glass fiber posts, all roots were stored at 100% humidity until testing. For push-out test, 1-mm thick slices were produced. The push-out test was performed in a universal testing machine at a crosshead speed of 0.5 mm/minute and the values (MPa) were analyzed by Kolmogorov-Smirnov and Levene's tests and by two-way ANOVA and Tukey's post hoc test at a significance level of 5%. Results Fiber posts cemented using Luting & Lining Cement, Fuji II LC Improved, and Ketac Cem presented the highest bond strength to root dentin, followed by RelyX Luting. Ionoseal presented the lowest bond strength values (P>0.05). The post level did not influence the bond strength of fiber posts to root dentin (P=0.148). The major cause of failure was cohesive at the cement for all GICs and RMGICs. Conclusions Except for Ionoseal, all cements provided satisfactory bond strength values. PMID:25004052

Effects of curing protocol and storage time on the micro-hardness of resin cements used to lute fiber-reinforced resin posts

PubMed Central

RAMOS, Marcelo Barbosa; PEGORARO, Thiago Amadei; PEGORARO, Luiz Fernando; CARVALHO, Ricardo Marins

2012-01-01

Objectives To determine the micro-hardness profile of two dual cure resin cements (RelyX - U100®, 3M-ESPE and Panavia F 2.0®, Kuraray) used for cementing fiber-reinforced resin posts (Fibrekor® - Jeneric Pentron) under three different curing protocols and two water storage times. Material and methods Sixty 16mm long bovine incisor roots were endodontically treated and prepared for cementation of the Fibrekor posts. The cements were mixed as instructed, dispensed in the canal, the posts were seated and the curing performed as follows: a) no light activation; b) light-activation immediately after seating the post, and; c) light-activation delayed 5 minutes after seating the post. The teeth were stored in water and retrieved for analysis after 7 days and 3 months. The roots were longitudinally sectioned and the microhardness was determined at the cervical, middle and apical regions along the cement line. The data was analyzed by the three-way ANOVA test (curing mode, storage time and thirds) for each cement. The Tukey test was used for the post-hoc analysis. Results Light-activation resulted in a significant increase in the microhardness. This was more evident for the cervical region and for the Panavia cement. Storage in water for 3 months caused a reduction of the micro-hardness for both cements. The U100 cement showed less variation in the micro-hardness regardless of the curing protocol and storage time. Conclusions The micro-hardness of the cements was affected by the curing and storage variables and were material-dependent. PMID:23138743

Radiopacity of different resin-based and conventional luting cements compared to human and bovine teeth.

PubMed

Pekkan, Gürel; Ozcan, Mutlu

2012-02-03

This study evaluated the radiopacity of different resin-based luting materials and compared the results to human and bovine dental hard tissues. Disc specimens (N=130, n=10 per group) (diameter: 6 mm, thickness: 1 mm) were prepared from 10 resin-based and 3 conventional luting cements. Human canine dentin (n=10), bovine enamel (n=10), bovine dentin (n=10) and Aluminium (Al) step wedge were used as references. The optical density values of each material were measured from radiographic images using a transmission densitometer. Al step wedge thickness and optical density values were plotted and equivalent Al thickness values were determined for radiopacity measurements of each material. The radiopacity values of conventional cements and two resin luting materials (Rely X Unicem and Variolink II), were significantly higher than that of bovine enamel that could be preferred for restorations cemented on enamel. Since all examined resin-based luting materials showed radiopacity values equivalent to or greater than that of human and bovine dentin, they could be considered suitable for the restorations cemented on dentin.

Shear bond strength of porcelain laminate veneers to enamel, dentine and enamel-dentine complex bonded with different adhesive luting systems.

PubMed

Öztürk, Elif; Bolay, Şükran; Hickel, Reinhard; Ilie, Nicoleta

2013-02-01

The aim of this study was to evaluate the shear bond strength of porcelain laminate veneers to 3 different surfaces by means of enamel, dentine, and enamel-dentine complex. One hundred thirty-five extracted human maxillary central teeth were used, and the teeth were randomly divided into 9 groups (n=15). The teeth were prepared with 3 different levels for bonding surfaces of enamel (E), dentine (D), and enamel-dentine complex (E-D). Porcelain discs (IPS e.max Press, Ivoclar Vivadent) of 2mm in thickness and 4mm in diameter were luted to the tooth surfaces by using 2 light-curing (RelyX Veneer [RV], 3M ESPE; Variolink Veneer [VV], Ivoclar Vivadent) and a dual-curing (Variolink II [V2], Ivoclar Vivadent) adhesive systems according to the manufacturers' instructions. Shear bond strength test was performed in a universal testing machine at 0.5mm/min until bonding failure. Failure modes were determined under a stereomicroscope, and fracture surfaces were evaluated with a scanning electron microscope. The data were statistically analysed (SPSS 17.0) (p=0.05). Group RV-D exhibited the lowest bond strength value (5.42±6.6MPa). There was statistically no difference among RV-D, V2-D (13.78±8.8MPa) and VV-D (13.84±6.2MPa) groups (p>0.05). Group VV-E exhibited the highest bond strength value (24.76±8.8MPa). The type of tooth structure affected the shear bond strength of the porcelain laminate veneers to the 3 different types of tooth structures (enamel, dentine, and enamel-dentine complex). When dentine exposure is necessary during preparation, enough sound enamel must be protected as much as possible to maintain a good bonding; to obtain maximum bond strength, preparation margins should be on sound enamel. Copyright © 2012 Elsevier Ltd. All rights reserved.

Mechanical properties and micro-morphology of fiber posts.

PubMed

Zicari, F; Coutinho, E; Scotti, R; Van Meerbeek, B; Naert, I

2013-04-01

To evaluate flexural properties of different fiber posts systems and to morphologically characterize their micro-structure. Six types of translucent fiber posts were selected: RelyX Post (3M ESPE), ParaPost Taper Lux (Colthéne-Whaledent), GC Fiber Post (GC), LuxaPost (DMG), FRC Postec Plus (Ivoclar-Vivadent), D.T. Light-Post (RTD). For each post system and size, ten specimens were subjected to a three-points bending test. Maximum fracture load, flexural strength and flexural modulus were determined using a universal loading device (5848 MicroTester(®), Instron). Besides, for each system, three intact posts of similar dimensions were processed for scanning electron microscopy to morphologically characterize the micro-structure. The following structural characteristics were analyzed: fibers/matrix ratio, density of fibers, diameter of fibers and distribution of fibers. Data were statistically analyzed with ANOVA. Type and diameter of posts were found to significantly affect the fracture load, flexural strength and flexural modulus (p<0.05). Regarding maximum fracture load, it was found to increase with post diameter, in each post system (p<0.001). Regarding flexural strength and flexural modulus, the highest values were recorded for posts with the smallest diameter (p<0.001). Finally, structural characteristics significantly varied among the post systems tested. However, any correlation has been found between flexural strength and structural characteristics. Flexural strength appeared not to be correlated to structural characteristics of fiber posts, but it may rather be affected by mechanical properties of the resin matrix and the interfacial adhesion between fibers and resin matrix. Copyright © 2013. Published by Elsevier Ltd.

Influence of Different Ceramic Systems on Marginal Misfit.

PubMed

Vargas, S P; Neves, A C C; Vitti, R; Amaral, M; Henrique, M N; Silva-Concílio, L R

2017-09-01

the aim of this study was to evaluate the marginal misfit at the interface between a ceramic coping and its abutment. Twenty-four specimens were made with solid abutments. The specimens were divided into 3 groups according to the ceramic system (n = 8): Lava (zirconia), IPS e.max Press (lithium disilicate), and IPS Empress Esthetic (leucite). All copings were cemented with resin luting agent (RelyX U200) and the marginal misfit were evaluated at 3 different times: initial, after cementation, and after mechanical cycling using a linear measuring microscope (Measuring Microscope STM-Olympus) at a magnification of 40x. All specimens were subjected to mechanical cycling (1 million cycles) by an universal testing machine (Instron 8800). The results were statistically analyzed using Analysis of Variance and Student's t-test (α = 0.05). all groups showed an increase in the marginal misfit after cementation. The lithium disilicate group demonstrated the lowest interacial gap values at each evaluation (p = 0.001). The zirconia and leucite groups showed similar interfacial gap values (initial, p = 0.244; and post cementation, p = 0.751). the cementation increase the marginal misfit, but the mechanical cycling did not influence the marginal misfit of the ceramics systems evaluated. Copyright© 2017 Dennis Barber Ltd.

Effect of Steam Autoclaving on the Tensile Strength of Resin Cements Used for Bonding Two-Piece Zirconia Abutments.

PubMed

Fadanelli, Marcos Alexandre; Amaral, Flávia Lucisano Botelho do; Basting, Roberta Tarkany; Turssi, Cecilia Pedroso; Sotto-Maior, Bruno Salles; França, Fabiana Mantovani Gomes

2017-04-01

The purpose of this study was to evaluate the effects of steam autoclave sterilization on the tensile strength of two types of resin cements used to bond customized CAD/CAM zirconia abutments onto titanium bases. Forty sets of zirconia abutments cemented to screwed titanium bases of implants analogs were divided into 4 groups (n = 10). Two groups were treated with a conventional chemically activated resin cement (ML, Multilink Ivoclar Vivadent) and the other two groups with a self-adhesive dual resin cement (RelyX U200, 3M ESPE). One group from each cement was submitted to steam autoclaving. The autoclave sterilization cycle was performed after 72 hours of cementation for 15 minutes at 121°C and 2.1 Kgf/cm 2 . The samples were subjected to tensile strength testing in a universal testing machine (200 Kgf, 0.5 mm/min), from which the means and standard deviations were obtained in Newtons. Results showed (via ANOVA and Tukey's test; α = 0.05) that in the absence of steam autoclaving, no difference was observed in tensile strength between the cements tested: ML: 344.87 (93.79) and U200: 280 (92.42) (P = .314). Steam autoclaving, however, significantly increased tensile strength for the ML: 465.42 (87.87) compared to U200: 289.10 (49.02) (P < .001). Despite the significant increase in the ML samples (P = .013), autoclaving did not affect the tensile strength of the U200 samples (P > 0.05). The authors concluded that steam autoclaving increases the mean tensile strength of the chemically activated cement compared to the dual-cure self-adhesive cement. The performance of both cements evaluated was similar if the sterilization step was disconsidered.

Effect of chlorhexidine and ethanol on the durability of the adhesion of the fiber post relined with resin composite to the root canal.

PubMed

Cecchin, Doglas; de Almeida, José Flávio Affonso; Gomes, Brenda P F A; Zaia, Alexandre Augusto; Ferraz, Caio Cesar Randi

2011-05-01

The aim of this study was to investigate the effects of pretreatment of gel chlorhexidine and ethanol on the bond strength and durability of the adhesion of the fiber post relined with resin composite to the root dentin. Sixty bovine incisor roots were divided into four groups: irrigation with physiologic solution (control), 5 minutes with chlorhexidine, 1 minute with ethanol, and 5 minutes with chlorhexidine followed by 1 minute with ethanol. Fiber posts relined with resin composite were cemented with RelyX ARC (3M ESPE, St Paul, MN) and a self-etching adhesive system Clearfil SE Bond (Kuraray, Kurashiki, Japan). Each group was randomly divided into three subgroups: 24 hours of water storage, 12 months of water storage, and 12 months of oil storage. All roots were sectioned transversely in the coronal, middle, and apical regions, producing 1-mm thick slices, and the push-out test was performed. Statistical analysis was performed using analysis of variance and the Tukey test for post hoc comparisons (α = 0.05). Immediate groups showed similar bond strength values with or without chlorhexidine and/or ethanol pretreatment (P > .05). A significant decrease in the bond strength in the control group was observed after 12 months of storage in water and oil (P < .05). The use of chlorhexidine- and/or ethanol-preserved bond strength in the groups stored in water and oil for 12 months (P < .05). Chlorhexidine and/or ethanol pretreatment were capable of preserving the bond strength of the fiber post relined with resin composite to root dentin for 12 months. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Influence of Etching Protocol and Silane Treatment with a Universal Adhesive on Lithium Disilicate Bond Strength.

PubMed

Kalavacharla, V K; Lawson, N C; Ramp, L C; Burgess, J O

2015-01-01

To measure the effects of hydrofluoric acid (HF) etching and silane prior to the application of a universal adhesive on the bond strength between lithium disilicate and a resin. Sixty blocks of lithium disilicate (e.max CAD, Ivoclar Vivadent) were sectioned into coupons and polished. Specimens were divided into six groups (n=10) based on surface pretreatments, as follows: 1) no treatment (control); 2) 5% HF etch for 20 seconds (5HF); 3) 9.5% HF etch for 60 seconds (9.5HF); 4) silane with no HF (S); 5) 5% HF for 20 seconds + silane (5HFS); and 6) 9.5% HF for 60 seconds + silane (9.5HFS). All etching was followed by rinsing, and all silane was applied in one coat for 20 seconds and then dried. The universal adhesive (Scotchbond Universal, 3M ESPE) was applied onto the pretreated ceramic surface, air thinned, and light cured for 10 seconds. A 1.5-mm-diameter plastic tube filled with Z100 composite (3M ESPE) was applied over the bonded ceramic surface and light cured for 20 seconds on all four sides. The specimens were thermocycled for 10,000 cycles (5°C-50°C/15 s dwell time). Specimens were loaded until failure using a universal testing machine at a crosshead speed of 1 mm/min. The peak failure load was used to calculate the shear bond strength. Scanning electron microscopy images were taken of representative e.max specimens from each group. A two-way analysis of variance (ANOVA) determined that there were significant differences between HF etching, silane treatment, and the interaction between HF and silane treatment (p<0.01). Silane treatment provided higher shear bond strength regardless of the use or concentration of the HF etchant. Individual one-way ANOVA and Tukey post hoc analyses were performed for each silane group. Shear bond strength values for each etch time were significantly different (p<0.01) and could be divided into significantly different groups based on silane treatment: no silane treatment: 0 HF < 5% HF < 9.5% HF; and RelyX silane treatment: 0 HF < 5% HF and 9.5% HF. Both HF and silane treatment significantly improved the bond strength between resin and lithium disilicate when used with a universal adhesive.

Effect of different surface treatments on shear bond strength of zirconia to three resin cements

NASA Astrophysics Data System (ADS)

Dadjoo, Nisa

Statement of problem: There are no standard guidelines for material selection to obtain acceptable bonding to high-strength zirconium oxide ceramic. Studies suggest resin cements in combination with MDP-containing primer is a reasonable choice, however, the other cements cannot be rejected and need further investigation. Objective: The purpose of this in vitro study was the evaluation of the shear bond strength of three composite resin cements to zirconia ceramic after using different surface conditioning methods. Materials and methods: One hundred and twenty sintered Y-TZP ceramic (IPS e.max ZirCAD) squares (8 x 8 x 4 mm) were embedded in acrylic molds, then divided into three groups (n=40) based on the type of cement used. Within each group, the specimens were divided into four subgroups (n=10) and treated as follows: (1) Air abrasion with 50microm aluminum oxide (Al2O 3) particles (ALO); (2) Air abrasion + Scotchbond Universal adhesive (SBU); (3) Air abrasion + Monobond Plus (MBP); (4) Air abrasion + Z-Prime Plus (ZPP). Composite cylinders were used as carriers to bond to conditioned ceramic using (1) RelyX Ultimate adhesive resin cement (RX); (2) Panavia SA self-adhesive resin cement (PSA); (3) Calibra esthetic cement (CAL). The bonded specimens were submerged in distilled water and subjected to 24-hour incubation period at 37°C. All specimens were stressed in shear at a constant crosshead speed of 0.5 mm/min until failure. Statistical analysis was performed by ANOVA. The bond strength values (MPa), means and standard deviations were calculated and data were analyzed using analysis of variance with Fisher's PLSD multiple comparison test at the 0.05 level of significance. The nature of failure was recorded. Results: The two-way ANOVA showed Panavia SA to have the highest strength at 44.3 +/- 16.9 MPa (p<0.05). The combination of Scotchbond Universal surface treatment with Panavia SA cement showed statistically higher bond strength (p=0.0054). The highest bond strengths for all three cements were observed with Scotchbond Universal surface treatment (p=0.0041). Calibra in combination with aluminum oxide air abrasion resulted in statistically lowest bond strength at 12.0 +/- 3.9 MPa. The predominant mode of failure was cohesive with cement remaining principally on the zirconium oxide samples in 57.5% of the specimens, followed by cement found on both the zirconium oxide samples and composite rods (mixed) in 32.5% of the samples. Only 10% of the specimens were found with cement on the composite rods (adhesive failure). Conclusions: Within the limitations of this in vitro study, the MDP-containing resin cement, Panavia SA, yielded the strongest bond to Y-TZP ceramic when compared to adhesive (RelyX Ultimate) or esthetic (Calibra) resin cements. Air abrasion particle + Scotchbond Universal surface treatment demonstrated the highest bond strength regardless of the cement. Significance: The variation of surface conditioning methods yielded different results in accordance with the cement types. Overall, Scotchbond Universal adhesive + air abrasion yielded the highest bond strengths among all three surface treatments. The phosphate monomer-containing luting system, Panavia SA, is acceptable for bonding to zirconia ceramics.

Overlays or ceramic fragments for tooth restoration: an analysis of fracture resistance.

PubMed

Tavarez, Rudys Rodolfo de Jesus; Firoozmand, Leily Macedo; Silva, Mônica Barros; Malheiros, Adriana Santos; Bandéca, Matheus Coelho

2014-01-01

The aim of this study was to evaluate the mode of fracture and resistance of partial ceramic restorations of posterior teeth. Thirty healthy upper premolars were selected and divided into three groups (n = 10): Group 1- control, healthy unrestored teeth, group 2-teeth restored with ceramic fragments; and group 3-teeth restored with ceramic overlays. The restorations were manufactured with feldspathic ceramic and cemented with RelyX ARC resin cement. After being stored in distilled water for 7 days, the teeth were subjected to axial compression mechanical testing with a universal testing machine. Force was applied to the long axis of the tooth at a speed of 0.5 mm/min until fracture. The data were analyzed with one-way ANOVA and Tukey's test (5%). The mode of fracture was scored according to the degree of involvement of the tooth structure and the type of restoration. A significant difference (p < 0.05) was showed between groups 2 (1155 N) and 3 (846.6 N), but there was no significant difference between group 1 and the other groups (1046 N), More extensive fractures were prevalent in the healthy teeth group (Group 1), which had no occlusal coverage; less severe fractures were found in groups 2 and 3. We conclude that teeth restored with ceramic fragments may offer greater resistance to fractures compared to teeth that have overlay restorations.

Evaluation of the fracture resistance of computer-aided design/computer-aided manufacturing monolithic crowns prepared in different cement thicknesses.

PubMed

Sagsoz, N Polat; Yanıkoglu, N

2018-04-01

The purpose of this study was to evaluate the fracture resistance of monolithic computer-aided design/computer-aided manufacturing (CAD/CAM) crowns that are prepared with different cement thickness. For this investigation, a human maxillary premolar tooth was selected. Master model preparation was performed with a demand bur under water spray. Master die was taken to fabricate 105 epoxy resin replicas. The crowns were milled using a CEREC 4 CAD/CAM system (Software Version, 4.2.0.57192). CAD/CAM crowns were made using resin nanoceramic, feldspathic glass ceramic, lithium disilicate, and leucite-reinforced ceramics. Each group was subdivided into three groups in accordance with three different cement thicknesses (30, 90, and 150 μm). Crowns milled out. Then RelyX ™ U200 was used as a luting agent to bond the crowns to the prepared samples. After one hour cementations, the specimens were stored in water bath at 37°C for 1 week before testing. Seven unprepared and unrestored teeth were kept and tested as a control group. A universal test machine was used to assume the fracture resistance of all specimens. The compressive load (N) that caused fracture was recorded for each specimen. Fracture resistance data were statistically analyzed by one-way ANOVA and two-factor interaction modeling test (α = 0.001). There are statistically significant differences between fracture resistances of CAD/CAM monolithic crown materials (P < 0.001). It is seen that cement thickness is not statistically significant for fracture resistance of CAD/CAM monolithic crowns (P > 0.001). CAD/CAM monolithic crown materials affected fracture resistance. Cement thickness (30, 90, and 150 μm) was not effective on fracture resistance of CAD/CAM monolithic crowns.

Optical X-ray density of composite resin luting agents.

PubMed

Carracho, Helena G; da Silveira, Ivori D; Soares, Clarissa G; Paranhos, Maria Paula G; Júnior, Luiz Henrique Burnett; Spohr, Ana Maria

2011-01-01

This study verified the optical density of four composite resin luting agents - RelyX ARC (RY), Enforce (E), C&B Cement (CB) and Flow it (FI), at thicknesses of 2, 3, and 4 mm. The optical density of the luting agents was compared with that of enamel and dentin at the same thicknesses. Fifteen tooth crowns were embedded in PVC cylinders with self-cured acrylic resin. In addition, acrylic resin was poured into 5 PVC cylinders and four equidistant 5 mm diameter holes were prepared, with one luting material inserted in each. A laboratory cutting machine was used to prepare 4-, 3- and 2-mm thick slices of the tooth crowns and materials. Digital images were obtained with a Digora system. Three radiographs of each thickness were obtained, totalizing 135 radiographs of the crowns and 45 of the materials. Three readings were carried out on each radiograph: three in enamel, three in dentin and three in each material, totalizing 1350. According to Students t-test (p

The effect of different shades of specific luting agents and IPS empress ceramic thickness on overall color.

PubMed

Terzioğlu, Hakan; Yilmaz, Burak; Yurdukoru, Bengul

2009-10-01

The color stability of both porcelain and luting materials is very important for the esthetics of laminate veneers and all-ceramic crowns. The purpose of this study was to determine the effect of different shades of resin-based luting cement and the thickness of IPS Empress ceramics on the final color of the restorations. Resin-based dual-polymerized composite cement in two different shades (RelyX ARC) and ceramic disks of different thicknesses were selected for the study. Forty specimens (ten each of four different thicknesses: 0.5 mm, 1 mm, 2 mm, and 3 mm) were used for the evaluation. Initial specimen color parameters were determined in a Commission Internationale de l'Eclairage L*a*b* color order system with a colorimeter. Two different shades of the cement were prepared as polymerized layers and applied to one face of the specimens in order. Color changes were calculated between baseline color measurements and measurements after cementation. Color difference data were analyzed statistically. All specimens showed a significant color shift (DE > 3.7) after cementation regardless of the cement shade. However, the differences in the cement shade did not significantly affect the final color of the ceramic specimens for any thickness, and color shifts were not perceivable between the different shades of cement. (Int J Periodontics Restorative Dent 2009;29:499-505.).

Randomized Clinical Trial of Implant-Supported Ceramic-Ceramic and Metal-Ceramic Fixed Dental Prostheses: Preliminary Results

PubMed Central

Esquivel-Upshaw, Josephine F.; Clark, Arthur E.; Shuster, Jonathan J.; Anusavice, Kenneth J.

2013-01-01

Purpose The aim of this study was to determine the survival rates over time of implant-supported ceramic-ceramic and metal-ceramic prostheses as a function of core-veneer thickness ratio, gingival connector embrasure design, and connector height. Materials and Methods An IRB-approved, randomized, controlled clinical trial was conducted as a single-blind pilot study involving 55 patients missing three teeth in either one or two posterior areas. These patients (34 women; 21 men; age range 52–75 years) were recruited for the study to receive a 3-unit implant-supported fixed dental prosthesis (FDP). Two implants were placed for each of the 72 FDPs in the study. The implants (Osseospeed, Astra Tech), which were made of titanium, were grit blasted. A gold-shaded, custom-milled titanium abutment (Atlantis, Astra Tech), was secured to each implant body. Each of the 72 FDPs in 55 patients were randomly assigned based on one of the following options: (1) A. Material: ceramic-ceramic (Yttria-stabilized zirconia core, pressable fluorapatite glass-ceramic, IPS e.max ZirCAD and ZirPress, Ivoclar Vivadent) B. metal-ceramic (palladium-based noble alloy, Capricorn, Ivoclar Vivadent, with press-on leucite-reinforced glass-ceramic veneer, IPS InLine POM, Ivoclar Vivadent); (2) occlusal veneer thickness (0.5, 1.0, and 1.5 mm); (3) curvature of gingival embrasure (0.25, 0.5, and 0.75 mm diameter); and (4) connector height (3, 4, and 5 mm). FDPs were fabricated and cemented with dual-cure resin cement (RelyX, Universal Cement, 3M ESPE). Patients were recalled at 6 months, 1 year, and 2 years. FDPs were examined for cracks, fracture, and general surface quality. Results Recall exams of 72 prostheses revealed 10 chipping fractures. No fractures occurred within the connector or embrasure areas. Two-sided Fisher’s exact tests showed no significant correlation between fractures and type of material system (p = 0.51), veneer thickness (p = 0.75), radius of curvature of gingival embrasure (p = 0.68), and connector height (p = 0.91). Conclusions Although there were no significant associations between connector height, curvature of gingival embrasure, core/veneer thickness ratio, and material system and the survival probability of implant-supported FDPs with zirconia as a core material, the small number of fractures precludes a definitive conclusion on the dominant controlling factor. PMID:23758092

Effect of Root Canal Sealers on Bond Strength of Fiber Posts to Root Dentin Cemented after one Week or six Months

PubMed Central

Ruiz, Lucas; Mongruel Gomes, Giovana; Bittencourt, Bruna; Rutz da Silva, Fabrício; Mongruel Gomes, Osnara Maria; Chidoski Filho, Julio Cezar; Lincoln Calixto, Abraham

2018-01-01

Eugenol-based root canal sealers (RCS) have been widely used by clinicians; however, their effect on resinous materials is still questionable. The objective of this study was to evaluate the influence of RCS at 1 week and 6 months’ post obturation on the bond strength (BS) of glass fiber posts (GFP) to root dentin, using conventional and self-adhesive cementation systems (CS). The roots of 56 extracted human canines, were divided in eight groups (n=7) according to the combination of the following factors: RCS (with or without eugenol-Endofill and Sealer 26, respectively), storage period post obturation and prior GFP cementation (1 week and 6 months) and cementation systems (Variolink II - conventional resin cement or RelyX U200-self-adhesive resin cement). After one week, the specimens were transversely sectioned into six 1-mm-thick disks and were subjected to the push out BS test. The data were subjected to 3-way ANOVA and Tukey’s tests (α=0.05). The BS were not affected by the RCS, neither the CS (P>0.05). Just the period post obturation showed statistically significant differences (P 0.05), where the GFP cemented 6 months after the endodontic treatment showed higher values than those cemented 1 week after it. PMID:29692836

Amalgam shear bond strength to dentin using single-bottle primer/adhesive systems.

PubMed

Cobb, D S; Denehy, G E; Vargas, M A

1999-10-01

To evaluate the in vitro shear bond strengths (SBS) of a spherical amalgam alloy (Tytin) to dentin using several single-bottle primer/adhesive systems both alone: Single Bond (SB), OptiBond Solo (Sol), Prime & Bond 2.1 (PB), One-Step (OS) and in combination with the manufacturer's supplemental amalgam bonding agent: Single Bond w/3M RelyX ARC (SBX) and Prime & Bond 2.1 w/Amalgam Bonding Accessory Kit (PBA). Two, three-component adhesive systems, Scotchbond Multi-Purpose (SBMP) and Scotchbond Multi-Purpose Plus w/light curing (S + V) and w/o light curing (S+) were used for comparison. One hundred eight extracted human third molars were mounted lengthwise in phenolic rings with acrylic resin. The proximal surfaces were ground to expose a flat dentin surface, then polished to 600 grit silicon carbide paper. The teeth were randomly assigned to 9 groups (n = 12), and dentin surfaces in each group were treated with an adhesive system according to the manufacturer's instructions, except for S + V specimens, where the adhesive was light cured for 10 s before placing the amalgam. Specimens were then secured in a split Teflon mold, having a 3 mm diameter opening and amalgam was triturated and condensed onto the treated dentin surfaces. Twenty minutes after condensation, the split mold was separated. Specimens were placed in distilled water for 24 hrs, then thermocycled (300 cycles, between 5 degrees C and 55 degrees C, with 12 s dwell time). All specimens were stored in 37 degrees C distilled water for 7 days, prior to shear strength testing using a Zwick Universal Testing Machine at a cross-head speed of 0.5 mm/min. The highest to the lowest mean dentin shear bond strength values (MPa) for the adhesive systems tested were: S + V (10.3 +/- 2.3), SBX (10.2 +/- 3.5), PBA, (6.4 +/- 3.6), SOL (5.8 +/- 2.5), SBMP (5.7 +/- 1.8), S+ (4.8 +/- 2.3), PB (2.7 +/- 2.6), SB (2.7 +/- 1.1) and OS (2.5 +/- 1.8). One-way ANOVA and Duncan's Multiple Range Test indicated significant differences among groups. SBX and S + V produced significantly higher amalgam to dentin shear bond strengths than all other adhesive systems. Bond strengths of amalgam to dentin for the single-bottle adhesives, SOL and PBA were comparable to the three-component systems, SBMP and S+ and were significantly greater than OS, SB and PB (P < 0.05).

An in situ evaluation of the polymerization shrinkage, degree of conversion, and bond strength of resin cements used for luting fiber posts.

PubMed

Pulido, Camilo Andrés; de Oliveira Franco, Ana Paula Gebert; Gomes, Giovana Mongruel; Bittencourt, Bruna Fortes; Kalinowski, Hypolito José; Gomes, João Carlos; Gomes, Osnara Maria Mongruel

2016-10-01

The behavior and magnitude of the deformations that occur during polymerization and the behavior of the luting agents of glass fiber posts inside the root canal require quantification. The purpose of this in vitro study was to investigate the in situ polymerization shrinkage, degree of conversion, and bond strength inside the root canal of resin cements used to lute fiber posts. Thirty maxillary canines were prepared to lute fiber posts. The teeth were randomly divided into 2 groups (n=15) according to the cementation system used, which included ARC, the conventional dual-polymerized resin cement RelyX ARC, and the U200 system, a self-adhesive resin cement, RelyX U200. Two fiber optic sensors with recorded Bragg gratings (FBG) were attached to each post before inserting the resin cement inside the root canal to measure the polymerization shrinkage (PS) of the cements in the cervical and apical root regions (με). Specimens were sectioned (into cervical and apical regions) to evaluate bond strength (BS) with a push-out test and degree of conversion (DC) with micro-Raman spectroscopy. Data were statistically analyzed with 2-way ANOVA and the Tukey honestly significant difference post hoc test (α=.05). The ARC and U200 system showed similar PS values (-276.4 ±129.2 με and -252.1 ±119.2 με, respectively). DC values from ARC were higher (87.5 ±2.7%) than those of U200 (55.9 ±9.7%). The cervical region showed higher DC values (74.8 ±15.2%) and PS values (-381.6 ±53.0 με) than those of the apical region (68.5 ±20.1% and -146.9 ±43.5 με, respectively) for both of the resin cements. BS was only statistically different between the cervical and apical regions for ARC (P<.05). The ARC system showed the highest PS and DC values compared with U200; and for both of the resin cements, the PS and DC values were higher at the cervical region than at the apical region of the canal root. BS was higher in the cervical region only for ARC. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Marginal Adaptation and Quality of Interfaces in Lithium Disilicate Crowns - Influence of Manufacturing and Cementation Techniques.

PubMed

Melo Freire, C A; Borges, G A; Caldas, Dbm; Santos, R S; Ignácio, S A; Mazur, R F

To evaluate the cement line thickness and the interface quality in milled or injected lithium disilicate ceramic restorations and their influence on marginal adaptation using different cement types and different adhesive cementation techniques. Sixty-four bovine teeth were prepared for full crown restoration (7.0±0.5 mm in height, 8.0 mm in cervical diameter, and 4.2 mm in incisal diameter) and were divided into two groups: CAD/CAM automation technology, IPS e.max CAD (CAD), and isostatic injection by heat technology, IPS e.max Press (PRESS). RelyX ARC (ARC) and RelyX U200 resin cements were used as luting agents in two activation methods: initial self-activation and light pre-activation for one second (tack-cure). Next, the specimens were stored in distilled water at 23°C ± 2°C for 72 hours. The cement line thickness was measured in micrometers, and the interface quality received scores according to the characteristics and sealing aspects. The evaluations were performed with an optical microscope, and scanning electron microscope images were presented to demonstrate the various features found in the cement line. For the cement line thickness, data were analyzed with three-way analysis of variance (ANOVA) and the Games-Howell test (α=0.05). For the variable interface quality, the data were analyzed with the Mann-Whitney U-test, the Kruskal-Wallis test, and multiple comparisons nonparametric Dunn test (α=0.05). The ANOVA presented statistical differences among the ceramic restoration manufacturing methods as well as a significant interaction between the manufacturing methods and types of cement (p<0.05). The U200 presented lower cement line thickness values when compared to the ARC with both cementation techniques (p<0.05). With regard to the interface quality, the Mann-Whitney U-test and the Kruskal-Wallis test demonstrated statistical differences between the ceramic restoration manufacturing methods and cementation techniques. The PRESS ceramics obtained lower scores than did the CAD ceramics when using ARC cement (p<0.05). Milled restorations cemented with self-adhesive resin cement resulted in a thinner cement line that is statistically different from that of CAD or pressed ceramics cemented with resin cement with adhesive application. No difference between one-second tack-cure and self-activation was noted.

Fracture resistance of endodontically treated teeth restored with Zirconia filler containing composite core material and fiber posts.

PubMed

Jeaidi, Zaid Al

2016-01-01

To assess the fracture resistance of endodontically treated teeth with a novel Zirconia (Zr) nano-particle filler containing bulk fill resin composite. Forty-five freshly extracted maxillary central incisors were endodontically treated using conventional step back preparation and warm lateral condensation filling. Post space preparation was performed using drills compatible for fiber posts (Rely X Fiber Post) on all teeth (n=45), and posts were cemented using self etch resin cement (Rely X Unicem). Samples were equally divided into three groups (n=15) based on the type of core materials, ZirconCore (ZC) MulticCore Flow (MC) and Luxacore Dual (LC). All specimens were mounted in acrylic resin and loads were applied (Universal testing machine) at 130° to the long axis of teeth, at a crosshead speed of 0.5 mm/min until failure. The loads and the site at which the failures occurred were recorded. Data obtained was tabulated and analyzed using a statistical program. The means and standard deviations were compared using ANOVA and Multiple comparisons test. The lowest and highest failure loads were shown by groups LC (18.741±3.02) and MC (25.16±3.30) respectively. Group LC (18.741±3.02) showed significantly lower failure loads compared to groups ZC (23.02±4.21) and MC (25.16±3.30) (p<0.01). However groups ZC (23.02±4.21) and MC (25.16±3.30) showed comparable failure loads (p=0.23). Fracture resistance of endodontically treated teeth restored with Zr filler containing bulk fill composite cores was comparable to teeth restored with conventional Zr free bulk fill composites. Zr filled bulk fill composites are recommended for restoration of endodontically treated teeth as they show comparable fracture resistance to conventional composite materials with less catastrophic failures.

[Curing mode of universal adhesives affects the bond strength of resin cements to dentin].

PubMed

Fu, Z R; Tian, F C; Zhang, L; Han, B; Wang, X Y

2017-02-18

To determine the effects of curing mode of one-step and two-step universal adhesives on the micro-tensile bond strength (μTBS) of different dual-cure resin cements to dentin. One-step universal adhesive Single Bond Universal (SBU), and two-step universal adhesive OptiBond Versa (VSA) were chosen as the subjects, one-step self-etching adhesive OptiBond All in One (AIO) and two-step self-etching adhesive Clearfil SE Bond (SEB) were control groups, and two dual-cure resin cements RelyX Ultimate (RLX) and Nexus 3 Universal (NX3) were used in this study. In this study, 80 extracted human molars were selected and the dentin surface was exposed using diamond saw. The teeth were divided into 16 groups according to the adhesives (AIO, SBU, SEB, VSA), cure modes of adhesives (light cure, non-light cure) and resin cements (RLX, NX3). The adhesives were applied on the dentin surface following the instruction and whether light cured or not, then the resin cements were applied on the adhesives with 1 mm thickness and light cured (650 mW/cm(2) for 20 s. A resin was built up (5 mm) on the cements and light cured layer by layer. After water storage for 24 h, the specimens were cut into resin-cement-dentin strips with a cross sectional area of 1 mm×1 mm and the μTBS was measured. Regarding one-step universal adhesive (SBU) light cured, the μTBS with RLX [(35.45±7.04) MPa] or NX3 [(26.84±10.39) MPa] were higher than SBU non-light cured with RLX [(17.93±8.93) MPa)] or NX3 [(10.07±5.89) MPa, P<0.001]. Compared with AIO, light-cured SBU combined with RLX presented higher μTBS than AIO group [(35.45±7.04) MPa vs. (24.86±8.42) MPa, P<0.05]. When SBU was not lighted, the μTBS was lower than AIO [(17.93±8.93) MPa vs. (22.28±7.57) MPa, P<0.05]. For two-step universal adhesive (VSA) and control adhesive (SEB), curing mode did not affect the μTBS when used with either RLX or NX3 (25.98-32.24 MPa, P>0.05). Curing mode of one-step universal adhesive may affect the μTBS between dual-cure resin cements and dentin, while for two-step universal adhesive, the curing mode and the type of resin cements did not influence the μTBS.

Randomized clinical trial of implant-supported ceramic-ceramic and metal-ceramic fixed dental prostheses: preliminary results.

PubMed

Esquivel-Upshaw, Josephine F; Clark, Arthur E; Shuster, Jonathan J; Anusavice, Kenneth J

2014-02-01

The aim of this study was to determine the survival rates over time of implant-supported ceramic-ceramic and metal-ceramic prostheses as a function of core-veneer thickness ratio, gingival connector embrasure design, and connector height. An IRB-approved, randomized, controlled clinical trial was conducted as a single-blind pilot study involving 55 patients missing three teeth in either one or two posterior areas. These patients (34 women; 21 men; age range 52-75 years) were recruited for the study to receive a three-unit implant-supported fixed dental prosthesis (FDP). Two implants were placed for each of the 72 FDPs in the study. The implants (Osseospeed, Astra Tech), which were made of titanium, were grit blasted. A gold-shaded, custom-milled titanium abutment (Atlantis, Astra Tech), was secured to each implant body. Each of the 72 FDPs in 55 patients were randomly assigned based on one of the following options: (1) A. ceramic-ceramic (Yttria-stabilized zirconia core, pressable fluorapatite glass-ceramic, IPS e.max ZirCAD, and ZirPress, Ivoclar Vivadent) B. metal-ceramic (palladium-based noble alloy, Capricorn, Ivoclar Vivadent, with press-on leucite-reinforced glass-ceramic veneer, IPS InLine POM, Ivoclar Vivadent); (2) occlusal veneer thickness (0.5, 1.0, and 1.5 mm); (3) curvature of gingival embrasure (0.25, 0.5, and 0.75 mm diameter); and (4) connector height (3, 4, and 5 mm). FDPs were fabricated and cemented with dual-cure resin cement (RelyX, Universal Cement, 3M ESPE). Patients were recalled at 6 months, 1 year, and 2 years. FDPs were examined for cracks, fracture, and general surface quality. Recall exams of 72 prostheses revealed 10 chipping fractures. No fractures occurred within the connector or embrasure areas. Two-sided Fisher's exact tests showed no significant correlation between fractures and type of material system (p = 0.51), veneer thickness (p = 0.75), radius of curvature of gingival embrasure (p = 0.68), and connector height (p = 0.91). Although there were no significant associations between connector height, curvature of gingival embrasure, core/veneer thickness ratio, and material system and the survival probability of implant-supported FDPs with zirconia as a core material, the small number of fractures precludes a definitive conclusion on the dominant controlling factor. © 2013 by the American College of Prosthodontists.

Effects of various etching protocols on the flexural properties and surface topography of fiber-reinforced composite dental posts.

PubMed

Aksornmuang, Juthatip; Chuenarrom, Chanya; Chittithaworn, Natjira

2017-09-26

The purpose of this study was to evaluate the flexural properties and surface topography of fiber posts surface-treated with various etching protocols. Seventy each of three types of fiber posts: RelyX Fiber Post, Tenax Fiber Trans, and D.T. Light-Post Illusion X-Ro, were randomly divided into 7 groups: no surface treatment, surface treated with hydrofluoric acid (HF) 4.5% for 60 s, HF 4.5% for 120 s, HF 9.6% for 15 s, HF 9.6% for 60 s, HF 9.6% for 120 s, and treated with H 2 O 2 24% for 10 min. The specimens were then subjected to a three-point bending test. Surface topographies of the posts were observed using a SEM. The results indicate that fiber post surface pretreatments had no adverse effects on the flexural properties. However, the fiber posts treated with high HF concentrations or long etching times seemed to have more surface irregularities.

Evaluation of Adhesive Bonding of Lithium Disilicate Ceramic Material with Duel Cured Resin Luting Agents

PubMed Central

Gundawar, Sham M.; Radke, Usha M.

2015-01-01

Purpose: The purpose of this vitro study was to comparatively evaluate the adhesive bonding of dual cured resin luting agents with lithium disilicate ceramic material. Materials and Methods: Porcelain laminate veneers were prepared with lithium disilicate ceramic material i.e. IPS Empress II( E-Max Press). These laminates were bonded with RelyX ARC, Panavia F 2.0, Variolink II, Duolink and Nexus NX3.The porcelain laminates were etched with 9.6% hydrofluoric acid (Pulpdent Corporation) for one minute, washed for 15 sec with three way syringe and dried for 15 sec with air syringe. The silane (Ultradent) was applied with the help of applicator tip in a single coat and kept undisturbed for one minute. The prepared surfaces of the premolars were treated with 37% phosphoric acid (Prime dent) for 15 sec, thoroughly rinsed and dried as per manufactures instructions. The shear bond test was carried out on all samples with the Universal testing machine (Instron U.S.A.) The scanning electron microscopic study was performed at the fractured interface of representative samples from each group of luting agents. Result: In this study, the highest value of shear bond strength was obtained for NEXUS NX3 and the lowest for VARIOLINK II. Conclusion: The difference in bond strength can be interpreted as the difference in fracture resistance of luting agents, to which shearing load was applied during the shear bond strength test. It is inferred from this study that the composition of the luting agent determines the adhesive characteristics in addition to surface treatment and bonding surface area. PMID:25859514

The effect of various adhesives, enamel etching, and base treatment on the failure frequency of customized lingual brackets: a randomized clinical trial.

PubMed

Mavreas, Dimitrios; Cuzin, Jean-François; Boonen, Guillaume; Vande Vannet, Bart

2018-05-25

The aim of this paper was to compare failure differences in precious metal customized lingual brackets bonded with three adhesive systems. Also, differences in failure of non-precious metal brackets with and without a silicatized base layer bonded with the same adhesive, as well as the influence of enamel etching prior to using a self-etching dual cure resin were explored. Five different groups were defined in a semi-randomized approach. Group 1 (IME): Maxcem Elite with 378 Incognito brackets and etched teeth, Group 2 (IMNE): Maxcem Elite with 193 Incognito brackets on non-etched teeth, Group 3 (INE): Nexus+Excite with 385 Incognito brackets, Group 4 (IRE): Relyx with 162 Incognito brackets, Group 5 (HRME) and Group 6 (HNRME): Maxcem Elite with 182 Harmony brackets with silicatized and non-slicatized bases respectively. Bracket failures were recorded over a 12-month period. The number of failures during the observation period was small in the various adhesives types of groups, as well as in HRME and HNRME groups, and the comparisons among those groups were non-significant (P > 0.05). A statistically significant difference (P < 0.05) was found between the IME and IMNE groups. 1. During the first year of treatment customized lingual brackets failure frequencies (rates) are not different for the three adhesive materials tested. 2. Eliminating the etching stage when using self-etch/self-adhesive adhesives, may lead to a dramatic increase in the failure rates. 3. Silicoating of stainless steel customized lingual brackets does not seem to influence the failure of the bonds.

Shear bond strength of computer-aided design and computer-aided manufacturing feldspathic and nano resin ceramics blocks cemented with three different generations of resin cement.

PubMed

Ab-Ghani, Zuryati; Jaafar, Wahyuni; Foo, Siew Fon; Ariffin, Zaihan; Mohamad, Dasmawati

2015-01-01

To evaluate the shear bond strength between the dentin substrate and computer-aided design and computer-aided manufacturing feldspathic ceramic and nano resin ceramics blocks cemented with resin cement. Sixty cuboidal blocks (5 mm × 5 mm × 5 mm) were fabricated in equal numbers from feldspathic ceramic CEREC(®) Blocs PC and nano resin ceramic Lava™ Ultimate, and randomly divided into six groups (n = 10). Each block was cemented to the dentin of 60 extracted human premolar using Variolink(®) II/Syntac Classic (multi-steps etch-and-rinse adhesive bonding), NX3 Nexus(®) (two-steps etch-and-rinse adhesive bonding) and RelyX™ U200 self-adhesive cement. All specimens were thermocycled, and shear bond strength testing was done using the universal testing machine at a crosshead speed of 1.0 mm/min. Data were analyzed using one-way ANOVA. Combination of CEREC(®) Blocs PC and Variolink(®) II showed the highest mean shear bond strength (8.71 Mpa), while the lowest of 2.06 Mpa were observed in Lava™ Ultimate and RelyX™ U200. There was no significant difference in the mean shear bond strength between different blocks. Variolink(®) II cement using multi-steps etch-and-rinse adhesive bonding provided a higher shear bond strength than the self-adhesive cement RelyX U200. The shear bond strength was not affected by the type of blocks used.

Fatigue resistance and microleakage of CAD/CAM ceramic and composite molar crowns.

PubMed

Kassem, Amr S; Atta, Osama; El-Mowafy, Omar

2012-01-01

The aim of this study was to determine effect of compressive cyclic loading on fatigue resistance and microleakage of monolithic CAD/CAM molar ceramic and composite crowns. Thirty-two extracted molars were prepared to receive CEREC crowns according to manufacturer's guidelines using a special paralleling device (Parallel-A-Prep). Sixteen feldspathic ceramic crowns (VITABLOCS Mark II) (VMII) and 16 resin-composite crowns (Paradigm-MZ100 blocks) (PMZ) were milled using a CEREC-3D machine. Eight crowns of each group were cemented to their respective teeth using self-etching resin cement (Panavia-F-2.0) (PAN), and eight were cemented using self-adhesive resin cement (RelyX-Unicem-Clicker) (RXU). Following storage for 1 week in water, specimens were subjected to uniaxial compressive cyclic loading in an Instron testing machine at 12 Hz for 1,000,000 cycles. Load was applied at the central fossa, and the cycle range was 60-600 N. Specimens were then subjected to microleakage testing. Data were statistically analyzed using factorial ANOVA and Post Hoc (Tukey HSD) tests. All composite crowns survived compressive cyclic loading without fracture, while three ceramic crowns from the subgroup cemented with RXU developed surface cracks at the center of occlusal surfaces, extending laterally. Microleakage scores of ceramic crowns cemented with PAN were significantly lower than those of the other three subgroups (p < 0.05). After 1,000,000 cycles of compressive cyclic loading, PMZ composite molar crowns were more fatigue-resistant than VMII ceramic crowns. Cement type had a significant effect on fatigue resistance of the ceramic crowns but not the composite ones. Microleakage scores of ceramic crowns cemented with PAN were significantly lower than those of the other subgroups (p < 0.05). © 2011 by The American College of Prosthodontists.

Effect of chlorhexidine and ethanol on push-out bond strength of fiber posts under cyclic loading.

PubMed

Cecchin, Doglas; Giacomin, Mateus; Farina, Ana Paula; Bhering, Cláudia Lopes; Mesquita, Marcelo Ferraz; Ferraz, Caio Cezar

2014-02-01

To investigate the effects of pretreatment with 2% chlorhexidine in a gel base (CHX) and 100% ethanol (EtOH) on the bond strength between fiber posts relined with resin composite and root dentin under cyclic loading. Forty bovine incisor roots were divided into four groups after phosphoric acid etching: group 1 (control), irrigation with physiological saline solution; group 2, 5 min pretreatment with CHX; group 3, 1 min pretreatment with EtOH; group 4, 5 min pretreatment with CHX followed by 1 min with EtOH. Fiber posts relined with resin composite were cemented with RelyX ARC and the etch-and-rinse adhesive system Scotchbond Multi-Purpose. Each group was randomly divided into two subgroups: 24 h of storage (immediate groups) and cyclic loading (loading groups) with 250,000 cycles in a controlled chewing simulator. All roots were sectioned transversely and push-out tests were performed. Failure modes were observed and the bond strength means were analyzed using ANOVA and Tukey's test (a = 0.05). The mean values for the bond strength test (MPa) in immediate groups were: group 1, 5.44 ± 1.48; group 2, 5.57 ± 1.41; group 3, 5.49 ± 1.48; group 4, 5.57 ± 1.42. Immediate groups showed similar bond strength values (p > 0.05). In the cyclic loading groups, the bond strength values were: group 1, 2.80 ± 0.79; group 2, 4.02 (1.30); group 3, 4.50 ± 1.67; group 4, 4.97 ± 2.00. After cyclic loading, a significant decrease in the control group was observed (p < 0.05), while CHX pretreatment resulted in intermediate values (p < 0.05) and EtOH alone or associated with CHX preserved the bond strength values (p > 0.05). Chlorhexidine and/or ethanol pretreatment preserved the bond strength of the fiber post after cyclic loading.

Fracture analysis of randomized implant-supported fixed dental prostheses

PubMed Central

Esquivel-Upshaw, Josephine F.; Mehler, Alex; Clark, Arthur E.; Neal, Dan; Anusavice, Kenneth J.

2014-01-01

Objective Fractures of posterior fixed dental all-ceramic prostheses can be caused by one or more factors including prosthesis design, flaw distribution, direction and magnitude of occlusal loading, and nature of supporting infrastructure (tooth root/implant), and presence of adjacent teeth. This clinical study of implant-supported, all-ceramic fixed dental prostheses, determined the effects of (1) presence of a tooth distal to the most distal retainer; (2) prosthesis loading either along the non-load bearing or load bearing areas; (3) presence of excursive contacts or maximum intercuspation contacts in the prosthesis; and (4) magnitude of bite force on the occurrence of veneer ceramic fracture. Methods 89 implant-supported FDPs were randomized as either a three-unit posterior metal-ceramic (Au-Pd-Ag alloy and InLine POM, Ivoclar, Vivadent) FDP or a ceramic-ceramic (ZirCAD and ZirPress, Ivoclar, Vivadent) FDP. Two implants (Osseospeed, Dentsply) and custom abutments (Atlantis, Dentsply) supported these FDPs, which were cemented with resin cement (RelyX Universal Cement). Baseline photographs were made with markings of teeth from maximum intercuspation (MI) and excursive function. Patients were recalled at 6 months and 1 to 3 years. Fractures were observed, their locations recorded, and images compared with baseline photographs of occlusal contacts. Conclusion No significant relationship exists between the occurrence of fracture and: (1) the magnitude of bite force; (2) a tooth distal to the most distal retainer; and (3) contacts in load-bearing or non-load-bearing areas. However, there was a significantly higher likelihood of fracture in areas with MI contacts only. Clinical Significance This clinical study demonstrates that there is a need to evaluate occlusion differently with implant-supported prostheses than with natural tooth supported prostheses because of the absence of a periodontal ligament. Implant supported prostheses should have minimal occlusion and lighter contacts than ones supported by natural dentition. PMID:25016139

[Analysis of different endodontic sealers and strategies of root canal irrigation on the bond strength of fiber posts].

PubMed

Zhu, Shujin; Liu, Cuiling; Zheng, Zheng; Yang, Liyuan; Gao, Xu

2015-06-01

To evaluate the influence of eugenol-containing and resin-containing endodontic sealers on the bond strength of fiber posts using different strategies of root canal irrigation. Forty-eight mandibular premolars were endodontically treated. The specimens were randomly assigned into two groups according to different endodontic sealers. Group A used Endofil (eugenol-containing endodontic sealer), and group B used AH-plus (resin-containing endodontic sealer). After post space preparation, each group was randomly assigned into three subgroups according to the strategies of root canal irrigation (eight premolars in each subgroup). Group Al and B1: 0.9%NaCl irrigation; Group A2 and B2: 17% ethylene diamine tetraacetic acid (EDTA)+5.25%NaClO+0.9%NaCl irrigation; Group A3 and B3: ultrasonic agitation associated with 1 7%EDTA+5.25%NaClO+0.9%NaCl. One week after the cementation of fiber posts using RelyX™ Unicem, a push-out test was performed to measure the bond strength of the posts. The microstructure of the root canal surface was examined under scanning electron microscope (SEM). The bond strengths of the six groups were as follows: Al (7.96±2.23) MPa, A2 (9.95±2.89) MPa, A3 (18.88±3.69) MPa, B1 (11.41±3.71) MPa, B2 (14.00±4.04) MPa, and B3 (19.14±3.27) MPa. Statistical analysis revealed a significant interaction between the different endodontic sealers and the strategies of root canal irrigation (P<0.05). Lower bond strength was found in group Al but not in group BI (P<0.05), and the same result was revealed when comparing group A2 and B2. No significant difference was observed between group A3 and B3 (P>0.05). SEM showed that the root canal in group A3 and B3 achieved the cleanest surface with nearly all dentine tubules opened. The eugenol-containing endodontic sealer can impair the bond strength of fiber posts compared with the resin-containing sealer when the root canal is irrigated by 0.9% NaCl or 17%EDTA+5.25%NaClO+0.9%NaC. No difference was observed between the two sealers when using 17%EDTA+5.25% NaCIO+0.9%NaCl combined with ultrasonic irrigation.

Dental Resin Cements-The Influence of Water Sorption on Contraction Stress Changes and Hydroscopic Expansion.

PubMed

Sokolowski, Grzegorz; Szczesio, Agata; Bociong, Kinga; Kaluzinska, Karolina; Lapinska, Barbara; Sokolowski, Jerzy; Domarecka, Monika; Lukomska-Szymanska, Monika

2018-06-08

Resin matrix dental materials undergo contraction and expansion changes due to polymerization and water absorption. Both phenomena deform resin-dentin bonding and influence the stress state in restored tooth structure in two opposite directions. The study tested three composite resin cements (Cement-It, NX3, Variolink Esthetic DC), three adhesive resin cements (Estecem, Multilink Automix, Panavia 2.0), and seven self-adhesive resin cements (Breeze, Calibra Universal, MaxCem Elite Chroma, Panavia SA Cement Plus, RelyX U200, SmartCem 2, and SpeedCEM Plus). The stress generated at the restoration-tooth interface during water immersion was evaluated. The shrinkage stress was measured immediately after curing and after 0.5 h, 24 h, 72 h, 96 h, 168 h, 240 h, 336 h, 504 h, 672 h, and 1344 h by means of photoelastic study. Water sorption and solubility were also studied. All tested materials during polymerization generated shrinkage stress ranging from 4.8 MPa up to 15.1 MPa. The decrease in shrinkage strain (not less than 57%) was observed after water storage (56 days). Self-adhesive cements, i.e., MaxCem Elite Chroma, SpeedCem Plus, Panavia SA Plus, and Breeze exhibited high values of water expansion stress (from 0 up to almost 7 MPa). Among other tested materials only composite resin cement Cement It and adhesive resin cement Panavia 2.0 showed water expansion stress (1.6 and 4.8, respectively). The changes in stress value (decrease in contraction stress or built up of hydroscopic expansion) in time were material-dependent.

Fracture resistance of computer-aided design and computer-aided manufacturing ceramic crowns cemented on solid abutments.

PubMed

Stona, Deborah; Burnett, Luiz Henrique; Mota, Eduardo Gonçalves; Spohr, Ana Maria

2015-07-01

Because no information was found in the dental literature regarding the fracture resistance of all-ceramic crowns using CEREC (Sirona) computer-aided design and computer-aided manufacturing (CAD-CAM) system on solid abutments, the authors conducted a study. Sixty synOcta (Straumann) implant replicas and regular neck solid abutments were embedded in acrylic resin and randomly assigned (n = 20 per group). Three types of ceramics were used: feldspathic, CEREC VITABLOCS Mark II (VITA); leucite, IPS Empress CAD (Ivoclar Vivadent); and lithium disilicate, IPS e.max CAD (Ivoclar Vivadent). The crowns were fabricated by the CEREC CAD-CAM system. After receiving glaze, the crowns were cemented with RelyX U200 (3M ESPE) resin cement under load of 1 kilogram. For each ceramic, one-half of the specimens were subjected to the fracture resistance testing in a universal testing machine with a crosshead speed of 1 millimeter per minute, and the other half were subjected to the fractured resistance testing after 1,000,000 cyclic fatigue loading at 100 newtons. According to a 2-way analysis of variance, the interaction between the material and mechanical cycling was significant (P = .0001). According to a Tukey test (α = .05), the fracture resistance findings with or without cyclic fatigue loading were as follows, respectively: CEREC VITABLOCKS Mark II (405 N/454 N) was statistically lower than IPS Empress CAD (1169 N/1240 N) and IPS e.max CAD (1378 N/1025 N) (P < .05). The IPS Empress CAD and IPS e.max CAD did not differ statistically (P > .05). According to a t test, there was no statistical difference in the fracture resistance with and without cyclic fatigue loading for CEREC VITABLOCS Mark II and IPS Empress CAD (P > .05). For IPS e.max CAD, the fracture resistance without cyclic fatigue loading was statistically superior to that obtained with cyclic fatigue loading (P < .05). The IPS Empress CAD and IPS e.max CAD showed higher fracture resistance compared with CEREC VITABLOCS Mark II. The cyclic fatigue loading negatively influenced only IPS e.max CAD. The CEREC VITABLOCS Mark II, IPS Empress CAD, and IPS e.max CAD ceramic crowns cemented on solid abutments showed sufficient resistance to withstand normal chewing forces. Copyright © 2015 American Dental Association. Published by Elsevier Inc. All rights reserved.

Effect of Instrumentation Techniques, Irrigant Solutions and Artificial accelerated Aging on Fiberglass Post Bond Strength to Intraradicular Dentin.

PubMed

Santana, Fernanda Ribeiro; Soares, Carlos José; Silva, Júlio Almeida; Alencar, Ana Helena Gonçalves; Renovato, Sara Rodrigues; Lopes, Lawrence Gonzaga; Estrela, Carlos

2015-07-01

To evaluate the effect of instrumentation techniques, irrigant solutions and specimen aging on fiberglass posts bond strength to intraradicular dentine. A total of 120 bovine teeth were prepared and randomized into control and experimental groups resulting from three study factors (instrumentation techniques, irrigant solutions, specimen aging). Posts were cemented with RelyX U100. Samples were submitted to push-out test and failure mode was evaluated under a confocal microscope. In specimens submitted to water artificial aging, nickel-titanium rotary instruments group presented higher bond strength values in apical third irrigated with NaOCl or chlorhexi-dine. Irrigation with NaOCl resulted in higher bond strength than ozonated water. Artificial aging resulted in significant bond strength increase. Adhesive cement-dentin failure was prevalent in all the groups. Root canal preparation with NiTi instruments associated with NaOCl irrigation and ethylenediaminetetra acetic acid (EDTA) increased bond strength of fiberglass posts cemented with self-adhesive resin cement to intraradicular dentine. Water artificial aging significantly increased post-Clinical significance: The understanding of factors that may influence the optimal bond between post-cement and cement-dentin are essential to the success of endodontically treated tooth restoration.

Effect of 2% chlorhexidine digluconate on bond strength of a glass-fibre post to root dentine.

PubMed

Wang, L; Pinto, T A; Silva, L M; Araújo, D F G; Martins, L M; Hannas, A R; Pedreira, A P R V; Francisconi, P A S; Honório, H M

2013-09-01

To assess the immediate influence of dentine bonding systems (DBS) associated with 2% chlorhexidine digluconate (CHX) on glass-fibre post-bond strength to root dentine, in terms of coronal, middle and apical thirds. Sixty bovine roots were root filled and randomly assigned to 1 of 6 groups (n = 10): SBMP (3-step etch-and-rinse system, Scotchbond Multi-Purpose), SB (2-step etch-and-rinse system, Single Bond 2), SE (2-step self-etching system, Clearfil SE Bond) and SBMP-CHX, SB-CHX and SE-CHX, respectively, associated with CHX. For all groups, a glass-fibre post was luted with a dual-cure resin cement, RelyX ARC. After 7-day storage, specimens were subjected to the push-out test. Failure modes were analysed under optical microscopy (40x). Bond strength values were statistically analysed by two-way anova and Bonferroni tests (P < 0.05). The effect of DBS was significant (P < 0.05), and SE reached higher bond strength in comparison with the other DBS tested. CHX association did not show improvement with any DBS (P > 0.05); rather, it negatively affected SE, which was detected for all thirds. There was no difference between thirds (P > 0.05), except for the SE-CHX, which presented lower values for the apical third (P < 0.05). Adhesive cement/dentine adhesive failure was predominant for all groups. CHX did not influence the failure mode for any DBS (P > 0.05). The performance of the dentine bonding systems was material dependent. CHX did not improve immediate bond strength; however, CHX negatively affected the bond strength of the self-etching system, especially in the third apical. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Influence of post pattern and resin cement curing mode on the retention of glass fibre posts.

PubMed

Poskus, L T; Sgura, R; Paragó, F E M; Silva, E M; Guimarães, J G A

2010-04-01

To evaluate the influence of post design and roughness and cement system (dual- or self-cured) on the retention of glass fibre posts. Two tapered and smooth posts (Exacto Cônico No. 2 and White Post No. 1) and two parallel-sided and serrated posts (Fibrekor 1.25 mm and Reforpost No. 2) were adhesively luted with two different resin cements--a dual-cured (Rely-X ARC) and a self-cured (Cement Post)--in 40 single-rooted teeth. The teeth were divided into eight experimental groups (n = 5): PFD--Parallel-serrated-Fibrekor/dual-cured; PRD--Parallel-serrated-Reforpost/dual-cured; TED--Tapered-smooth-Exacto Cônico/dual-cured; TWD--Tapered-smooth-White Post/dual-cured; PFS--Parallel-serrated-Fibrekor/self-cured; PRS--Parallel-serrated-Reforpost/self-cured; TES--Tapered-smooth-Exacto Cônico/self-cured; TWS--Tapered-smooth-White Post/self-cured. The specimens were submitted to a pull-out test at a crosshead speed of 0.5 mm min(-1). Data were analysed using analysis of variance and Bonferroni's multiple comparison test (alpha = 0.05). Pull-out results (MPa) were: PFD = 8.13 (+/-1.71); PRD = 8.30 (+/-0.46); TED = 8.68 (+/-1.71); TWD = 9.35 (+/-1.99); PFS = 8.54 (+/-2.23); PRS = 7.09 (+/-1.96); TES = 8.27 (+/-3.92); TWS = 7.57 (+/-2.35). No statistical significant difference was detected for posts and cement factors and their interaction. The retention of glass fibre posts was not affected by post design or surface roughness nor by resin cement-curing mode. These results imply that the choice for serrated posts and self-cured cements is not related to an improvement in retention.

Fatigue Resistance of CAD/CAM Resin Composite Molar Crowns

PubMed Central

Shembish, Fatma A.; Tong, Hui; Kaizer, Marina; Janal, Malvin N.; Thompson, Van P.; Opdam, Niek J.; Zhang, Yu

2016-01-01

Objective To demonstrate the fatigue behavior of CAD/CAM resin composite molar crowns using a mouth-motion step-stress fatigue test. Monolithic leucite-reinforced glass-ceramic crowns were used as a reference. Methods Fully anatomically shaped monolithic resin composite molar crowns (Lava Ultimate, n = 24) and leucite reinforced glass-ceramic crowns (IPS Empress CAD, n = 24) were fabricated using CAD/CAM systems. Crowns were cemented on aged dentin-like resin composite tooth replicas (Filtek Z100) with resin-based cements (RelyX Ultimate for Lava Ultimate or Multilink Automix for IPS Empress). Three step-stress profiles (aggressive, moderate and mild) were employed for the accelerated sliding-contact mouth-motion fatigue test. Twenty one crowns from each group were randomly distributed among these three profiles (1:2:4). Failure was designated as chip-off or bulk fracture. Optical and electronic microscopes were used to examine the occlusal surface and subsurface damages, as well as the material microstructures. Results The resin composite crowns showed only minor occlusal damage during mouth-motion step-stress fatigue loading up to 1700 N. Cross-sectional views revealed contact-induced cone cracks in all specimens, and flexural radial cracks in 2 crowns. Both cone and radial cracks were relatively small compared to the crown thickness. Extending these cracks to the threshold for catastrophic failure would require much higher indentation loads or more loading cycles. In contrast, all of the glass-ceramic crowns fractured, starting at loads of approximately 450 N. Significance Monolithic CAD/CAM resin composite crowns endure, with only superficial damage, fatigue loads 3 – 4 times higher than those causing catastrophic failure in glass-ceramic CAD crowns. PMID:26777092

Effect of light energy density on conversion degree and hardness of dual-cured resin cement.

PubMed

Komori, Paula Carolina de Paiva; de Paula, Andréia Bolzan; Martin, Airton Abrāo; Tango, Rubens Nisie; Sinhoreti, Mario Alexandre Coelho; Correr-Sobrinho, Lourenço

2010-01-01

This study evaluated the effect of different light energy densities on conversion degree (CD) and Knoop hardness number (KHN) of RelyX ARC (RLX) resin cement. After manipulation according to the manufacturer's instructions, RLX was inserted into a rubber mold (0.8 mm x 5 mm) and covered with a Mylar strip. The tip of the light-curing unit (LCU) was positioned in contact with the Mylar surface. Quartz-tungsten-halogen (QTH) and light-emitting diode (LED) LCUs with light densities of 10, 20 and 30 J/cm2 were used to light-cure the specimens. After light curing, the specimens were stored dry in lightproof containers at 37 degrees C. After 24 hours, the CD was analyzed by FT-Raman and, after an additional 24-hours, samples were submitted to Knoop hardness testing. The data of the CD (%) and KHN were submitted to two-way ANOVA and the Tukey's test (alpha = 0.05). QTH and LED were effective light curing units. For QTH, there were no differences among the light energy densities for CD or KHN. For LED, there was a significant reduction in CD with the light energy density set at 10 J/cm2. KHN was not influenced by the light-curing unit and by its light energy density.

Two-year evaluation indicates zirconia bridges acceptable alternative to PFMs.

PubMed

Perry, Ronald D; Kugel, Gerard; Sharma, Shradha; Ferreira, Susana; Magnuson, Britta

2012-01-01

The aim of this in-vivo study was to evaluate the 2-year clinical performance of zirconia computer-aided design/computer-aided manufacturing (CAD/CAM)-generated bridges. A total of 16 three- or four-unit Lava zirconia bridges were done on 15 subjects. The bridges were cemented using RelyX™ Unicem Self-Adhesive Universal Resin Cement. Evaluation was done at 6-month, 1-year, and 2-year recall visits. Evaluation criteria were color stability and matching, marginal integrity, marginal discoloration, incidence of caries, changes in restoration-tooth interface, changes in surface texture, postoperative sensitivity, maintenance of periodontal health, changes in proximal and opposing teeth, and maintenance of anatomic form. In each of these parameters, the bridges were rated in one of three possible categories: "A" (alpha)--ideal; "B" (bravo)--acceptable; and "C" (charlie)--unacceptable. After 2 years, 100% of the bridges were rated "A" for color stability and matching, marginal discoloration, incidence of caries, changes in restoration-tooth interface, changes in surface texture, postoperative sensitivity, and change in proximal or opposing teeth. In the parameter of marginal integrity, 6.25% of the bridges were rated "B;" the remaining 93.75% were rated "A." Maintenance of periodontal health was rated "B" for 6.25% of the bridges and "A" for 93.75%. At 2 years, 12.5% of the bridges rated "C" in maintenance of anatomic form and 87.5% rated "A." The overall clinical outcome was that the CAD/CAM-generated zirconia bridges were clinically acceptable.

Influence of cement thickness on resin-zirconia microtensile bond strength

PubMed Central

Lee, Tae-Hoon; Ahn, Jin-Soo; Shim, June-Sung; Han, Chong-Hyun

2011-01-01

PURPOSE The aim of this study was to evaluate the influence of resin cement thickness on the microtensile bond strength between zirconium-oxide ceramic and resin cement. MATERIALS AND METHODS Thirty-two freshly extracted molars were transversely sectioned at the deep dentin level and bonded to air-abraded zirconium oxide ceramic disks. The specimens were divided into 8 groups based on the experimental conditions (cement type: Rely X UniCem or Panavia F 2.0, cement thickness: 40 or 160 µm, storage: thermocycled or not). They were cut into microbeams and stored in 37℃ distilled water for 24 h. Microbeams of non-thermocycled specimens were submitted to a microtensile test, whereas those of thermocycled groups were thermally cycled for 18,000 times immediately before the microtensile test. Three-way ANOVA and Sheffe's post hoc tests were used for statistical analysis (α=95%). RESULTS All failures occurred at the resin-zirconia interface. Thermocycled groups showed lower microtensile bond strength than non-thermocycled groups (P<.001). Differences in cement thickness did not influence the resin-zirconia microtensile bond strength given the same resin cement or storage conditions (P>.05). The number of adhesive failures increased after thermocycling in all experimental conditions. No cohesive failure was observed in any experimental group. CONCLUSION When resin cements of adhesive monomers are applied over air-abraded zirconia restorations, the degree of fit does not influence the resin-zirconia microtensile bond strength. PMID:22053241

Interfacial Fracture Toughness of Adhesive Resin Cement-Lithium-Disilicate/Resin-Composite Blocks.

PubMed

Mesmar, Samer; Ruse, N Dorin

2017-09-15

Resin composite blocks (RCB) are advocated as alternative to ceramic blocks (CB). Prior to use, adherence to these materials should characterized. This study aimed to test the null hypothesis (H 0 ) that material and surface treatment combinations do not influence interfacial fracture toughness (K IC ) of a self-cured adhesive resin cement [RelyX Ultimate (RXU)] to RCB or CB, under nonaged and aged conditions. Two RCB, Lava Ultimate (LU) and Enamic (EN), and one CB, IPS e.max Press (EMP) were used. Half-size [(6 × 6 × 6 × 6 mm)] specimens were prepared for EMP (n = 30), EN (n = 30), and LU (n = 60). RCB specimens were prepared by wet cutting/grinding, while CB specimens were pressed. Surfaces of EMP and EN were preconditioned with hydrofluoric acid (5%); surfaces of LU were sandblasted with either 27 μm alumina (LUS) or 30 μm silica-modified alumina Rocatec soft (LUR). All specimens were bonded with Scotchbond Universal adhesive and RXU. Additionally, twenty (4 × 4 × 4 × 8 mm) RXU specimens were prepared. All specimens were stored in water at 37°C and tested after 1 and 60 days. Interfacial K IC was determined with the notchless triangular prism specimen K IC test. Results were analyzed with two-way ANOVA and Scheffé multiple means comparisons (α = 0.05). Preconditioned and selected fractured surfaces were characterized with scanning electron microscopy. At 24 hours, LUS-RXU and LUR-RXU had significantly higher interfacial K IC than EN-RXU and EMP-RXU and were not different from K IC of RXU. Aging lead to a significant decrease in K IC of RXU and interfacial K IC of LUS-RXU, LUR-RXU, and EMP-RXU; interfacial K IC of EN-RXU was not affected. Based on the results, H 0 was rejected. Under the conditions of this study, at 24 hours, interfacial K IC of LUS-RXU and LUR-RXU was superior to EMP-RXU and EN-RXU. Aging in water at 37°C did not affect interfacial K IC of EN-RXU but adversely affected K IC of RXU and the other interfacial K IC . The results suggest that RXU and its adherence to LU and EMP deteriorates upon exposure to water at 37°C. In making clinical decisions related to material selection, practitioners should consider in vitro results. © 2017 by the American College of Prosthodontists.

Effect of energy density and delay time on the degree of conversion and Knoop microhardness of a dual resin cement.

PubMed

Mainardi, Maria do Carmo A J; Giorgi, Maria Cecília C; Lima, Débora A N L; Marchi, Giselle M; Ambrosano, Gláucia M; Paulillo, Luiz A M S; Aguiar, Flávio H B

2015-02-01

In the present study, we evaluated the influence of the photo-curing delay time and energy density on the degree of conversion and the Knoop microhardness of a resin cement. Seventy-eight samples were assigned to 13 groups (n = 6), one of which received no light curing (control). The samples were made of a dual-cured resin cement (RelyX ARC) with the aid of a Teflon matrix, submitted to one of the following energy densities (J/cm²): 7, 14, 20, and 28. Delay times were immediate (0), 1 min, or 2 min. After 24 h, the degree of conversion and microhardness were measured at three segments: cervical, medium, and apical. Data were submitted to three-way anova and Tukey's and Dunnett's tests, the latest of which was used to compare the control to the experimental groups. No interaction was observed between delay time and energy density regarding the degree of conversion. The cervical segment showed the highest values, while the apical showed the lowest. Microhardness values concerning the cervical segment in all groups were statistically different from that obtained for the control. A high-irradiance light-curing unit allows for a reduced irradiation exposure time with a short delay time, aimed at tooth restorations using a dual-cured resin cement. © 2014 Wiley Publishing Asia Pty Ltd.

Tensile bond strength of an adhesive resin cement to different alloys having various surface treatments.

PubMed

Abreu, Amara; Loza, Maria A; Elias, Augusto; Mukhopadhyay, Siuli; Looney, Stephen; Rueggeberg, Frederick A

2009-02-01

The ability of a resin cement to bond to a restorative alloy is critical for maximal crown retention to nonideal preparations. Surface treatment and metal type may have an important role in optimizing resin-to-metal strength. The purpose of this study was to examine the effect of surface pretreatment on the tensile strength of base and noble metals bonded using a conventional resin cement. Cylindrical plastic rods (9.5 mm in diameter), cast in base (Rexillium NBF) or noble metal (IPS d.SIGN 53), were divided into rods 10 mm in length (n=10-12). Specimens were heated in a porcelain furnace to create an oxide layer. Test specimens were further subjected to airborne-particle abrasion (50-microm Al(2)O(3) particles) alone or with the application of a metal primer (Alloy Primer). Similarly treated rod ends were joined using resin cement (RelyX ARC), thermocycled (x500, 5 degrees -55 degrees C) and stored (24 hours, 37 degrees C) before debonding using a universal testing machine. Debond strength and failure site were recorded. Rank-based ANOVA for unbalanced designs was used to test for significant interaction (alpha=.050). Each pair of treatments was compared separately for each metal (Bonferroni-adjusted significance level of .0083, overall error rate for comparisons, .05). The 2 metals were compared separately for each of the 3 treatments using an adjusted significance level of .017, maintaining an overall error rate of .05. A multinomial logit model was used to describe the effect of metal type and surface pretreatment on failure site location (alpha=.05). Interaction between metal type and surface pretreatment was significant for stress values (P=.019). Metal type did not significantly affect tensile bond strength for any of the compared surface pretreatments. Metal primer significantly improved tensile bond strength for each metal type. Most failures tended to occur as either adhesive or mixed in nature. Metal primer application significantly enhanced tensile bond strength to base and noble metal. No significant differences in tensile strength were found between alloys. Differences in failure site incidence were found to be related to metal type and surface pretreatment.

[Effects of different surface conditioning agents on the bond strength of resin-opaque porcelain composite].

PubMed

Liu, Wenjia; Fu, Jing; Liao, Shuang; Su, Naichuan; Wang, Hang; Liao, Yunmao

2014-04-01

The objective of this research is to evaluate the effects of different silane coupling agents on the bond strength between Ceramco3 opaque porcelain and indirect composite resin. Five groups of Co-Cr metal alloy substrates were fabricated according to manufacturer's instruction. The surface of metal alloy with a layer of dental opaque porcelain was heated by fire. After the surface of opaque porcelain was etched, five different surface treatments, i.e. RelyX Ceramic Primer (RCP), Porcelain Bond Activator and SE Bond Primer (mixed with a proportion of 1:1) (PBA), Shofu Porcelain Primer (SPP), SE bond primer (SEP), and no primer treatment (as a control group), were used to combine P60 and opaque porcelain along with resin cement. Shear bond strength of specimens was tested in a universal testing machine. The failure modes of specimens in all groups were observed and classified into four types. Selected specimens were subjected to scanning electron microscope and energy disperse spectroscopy to reveal the relief of the fracture surface and to confirm the failure mode of different types. The experimental results showed that the values of the tested items in all the tested groups were higher than that in the control group. Group PBA exhibited the highest value [(37.52 +/- 2.14) MPa] and this suggested a fact that all of the specimens in group PBA revealed combined failures (failure occurred in metal-porcelain combined surface and within opaque porcelain). Group SPP and RCP showed higher values than SEP (P < 0.05) and most specimens of SPP and RCP performed combined failures (failure occurred in bond surface and within opaque porcelain or composite resin) while all the specimens in group SEP and control group revealed adhesive failures. Conclusions could be drawn that silane coupling agents could reinforce the bond strength of dental composite resin to metal-opaque porcelain substrate. The bond strength between dental composite resin and dental opaque porcelain could meet the clinical requirements.

Clinical efficacy of veneered zirconium dioxide-based posterior partial fixed dental prostheses: five-year results.

PubMed

Raigrodski, Ariel J; Yu, Alika; Chiche, Gerard J; Hochstedler, J L; Mancl, Lloyd A; Mohamed, Shawky E

2012-10-01

In recent years, zirconium dioxide-based partial fixed dental prostheses (FDP) have been suggested as an alternative treatment to traditional metal ceramic FDPs. However, clinical studies evaluating their longevity and related complications are limited. The purpose of this cohort clinical study was to assess the efficacy of zirconium dioxide-based posterior 3-unit FDPs. Twenty 3-unit posterior FDPs (Lava) were placed in 16 participants missing a second premolar or a first molar. All participants met specific inclusion and exclusion criteria and provided informed consent. All teeth were prepared in a standardized manner: occlusal reduction of 1.5 to 2 mm; axial reduction of 1 to 1.5 mm; a 1.0 mm 360-degree rounded shoulder placed 0.5 mm subgingivally on the facial aspect and supragingivally on the lingual aspect on sound tooth structure; and rounded internal line angles. Definitive impressions were made with vinyl polysiloxane impression material. Frameworks were fabricated by using computer-aided design and computer-aided manufacturing (CAD/CAM) technology with a uniform retainer thickness of 0.6 mm and a minimal connector surface area of 9 mm(2). Restorations were luted with resin-modified glass ionomer cement (Rely-X Luting). Participants were recalled at 2 weeks, 6 months, and 12 months, and thereafter, annually for up to 60 months. Clinical fracture measurements, marginal discoloration, marginal adaptation, radiographic proximal recurrent caries, and periapical pathoses were assessed over time by using modified Ryge criteria. The probability distributions of these variables were calculated for the baseline data and for the recall data. An analysis of survival was made by using the Kaplan-Meier method. Eighteen FDPs were clinically evaluated at 5 years and 1 at 48 months. Fifteen were rated Alpha for fracture measurements, and 2 were rated Bravo (minor chipping of veneering porcelain and not requiring restoration replacement). Two were rated Charlie (major chipping of veneering porcelain and requiring restoration replacement). Eighteen FDPs were rated Alpha for marginal integrity, and 1 rated Bravo. All restorations were rated Alpha for marginal discoloration. One participant experienced root fracture after 60 months, while another was treated surgically for a periapical pathosis on an endodontically treated abutment. Zirconium dioxide-based posterior 3-unit FDPs performed well after 5 years of service. Copyright © 2012 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Retention of zirconium oxide ceramic crowns with three types of cement.

PubMed

Palacios, Rosario P; Johnson, Glen H; Phillips, Keith M; Raigrodski, Ariel J

2006-08-01

Information about the retentive strength of luting agents for zirconium oxide-based crowns is limited. It is unknown if this type of high-strength ceramic restoration requires adhesive cementation to enhance retention. The purpose of this in vitro study was to determine the ability of selected luting agents to retain a representative zirconium oxide ceramic crown under clinically simulated conditions. Recently extracted human molars were prepared with a flat occlusal surface, 20-degree taper, and approximately 4-mm axial length. The axial and occlusal surface areas were determined, and specimens were distributed equally by total surface area into 3 cementation groups (n=12). Zirconium oxide ceramic copings (Procera AllZirkon) with an occlusal bar to facilitate removal were fabricated using computer-aided design/computer-assisted manufacturing (CAD/CAM) technology. All copings were airborne-particle abraded with 50-mum Al(2)O(3) and then cleaned in an ultrasonic bath with isopropyl alcohol. Provisional cement was removed from the prepared teeth, followed by a pumice prophy. After trial insertion, the copings were cleaned with phosphoric acid, rinsed, dried, and dehydrated with isopropyl alcohol. They were then cemented with a seating force of 10 kg per tooth, using either a composite resin cement with adhesive agent (Panavia F 2.0 and ED Primer A & B [PAN]), a resin-modified glass ionomer cement (Rely X Luting [RXL]), or a self-adhesive modified composite resin (Rely X Unicem [RXU]). The cemented copings were thermal cycled at 5 degrees C and 55 degrees C for 5000 cycles with a 15 second dwell time, and then removed along the path of insertion using a universal testing machine at 0.5 mm/min. The removal force was recorded, and the stress of dislodgement was calculated using the surface area of each preparation. A 1-way analysis of variance was used to analyze the data (alpha=.05). The nature of failure was also recorded. Mean dislodgement stresses were 5.1, 6.1, and 5.0 MPa for PAN, RXL, and RXU, respectively. The 1-way analysis of variance revealed no differences in mean crown removal stress among the 3 cementation groups. The predominant mode of failure was cement remaining principally on the zirconium oxide copings in 46% of the specimens, followed by cement found on the tooth in 25.7% of the specimens. Within the limitations of this study, the 3 luting agents, with mean removal stresses ranging from 5.0 to 6.1 MPa were not significantly different. The use of a composite resin cement with a bonding agent did not yield higher coping retention compared to the other 2 cements tested.

Effect of Self-Adhesive and Separate Etch Adhesive Dual Cure Resin Cements on the Bond Strength of Fiber Post to Dentin at Different Parts of the Root.

PubMed

Amiri, Ehsan Mohamadian; Balouch, Fariba; Atri, Faezeh

2017-05-01

Bonding of fiber posts to intracanal dentin is challenging in the clinical setting. This study aimed to compare the effect of self-adhesive and separate etch adhesive dual cure resin cements on the bond strength of fiber post to dentin at different parts of the root. This in-vitro experimental study was conducted on 20 single-rooted premolars. The teeth were decoronated at 1mm coronal to the cementoenamel junction (CEJ), and the roots underwent root canal treatment. Post space was prepared in the roots. Afterwards, the samples were randomly divided into two groups. In group 1, the fiber posts were cemented using Rely X Unicem cement, while in group 2, the fiber posts were cemented using Duo-Link cement, according to the manufacturer's instructions. The intracanal post in each root was sectioned into three segments of coronal, middle, and apical, and each cross-section was subjected to push-out bond strength test at a crosshead speed of 1mm/minute until failure. Push-out bond strength data were analyzed using independent t-test and repeated measures ANOVA. The bond strength at the middle and coronal segments in separate etch adhesive cement group was higher than that in self-adhesive cement group. However, the bond strength at the apical segment was higher in self-adhesive cement group compared to that in the other group. Overall, the bond strength in separate etch adhesive cement group was significantly higher than that in self-adhesive cement group (P<0.001). Bond strength of fiber post to intracanal dentin is higher after the use of separate etch adhesive cement compared to self-adhesive cement.

Evaluation of marginal fit of 2 CAD-CAM anatomic contour zirconia crown systems and lithium disilicate glass-ceramic crown.

PubMed

Ji, Min-Kyung; Park, Ji-Hee; Park, Sang-Won; Yun, Kwi-Dug; Oh, Gye-Jeong; Lim, Hyun-Pil

2015-08-01

This study was to evaluate the marginal fit of two CAD-CAM anatomic contour zirconia crown systems compared to lithium disilicate glass-ceramic crowns. Shoulder and deep chamfer margin were formed on each acrylic resin tooth model of a maxillary first premolar. Two CAD-CAM systems (Prettau®Zirconia and ZENOSTAR®ZR translucent) and lithium disilicate glass ceramic (IPS e.max®press) crowns were made (n=16). Each crown was bonded to stone dies with resin cement (Rely X Unicem). Marginal gap and absolute marginal discrepancy of crowns were measured using a light microscope equipped with a digital camera (Leica DFC295) magnified by a factor of 100. Two-way analysis of variance (ANOVA) and post-hoc Tukey's HSD test were conducted to analyze the significance of crown marginal fit regarding the finish line configuration and the fabrication system. The mean marginal gap of lithium disilicate glass ceramic crowns (IPS e.max®press) was significantly lower than that of the CAD-CAM anatomic contour zirconia crown system (Prettau®Zirconia) (P<.05). Both fabrication systems and finish line configurations significantly influenced the absolute marginal discrepancy (P<.05). The lithium disilicate glass ceramic crown (IPS e.max®press) had significantly smaller marginal gap than the CAD-CAM anatomic contour zirconia crown system (Prettau®Zirconia). In terms of absolute marginal discrepancy, the CAD-CAM anatomic contour zirconia crown system (ZENOSTAR®ZR translucent) had under-extended margin, whereas the CAD-CAM anatomic contour zirconia crown system (Prettau®Zirconia) and lithium disilicate glass ceramic crowns (IPS e.max®press) had overextended margins.

Effect of Cementation Technique of Individually Formed Fiber-Reinforced Composite Post on Bond Strength and Microleakage

PubMed Central

Makarewicz, Dominika; Le Bell-Rönnlöf, Anna-Maria B; Lassila, Lippo V.J.; Vallittu, Pekka K.

2013-01-01

Objectives: The aim of this study was to evaluate the effect of two different cementation techniques of individually formed E-glass fiber-reinforced composite (FRC) post on bond strength and microleakage. Methods: The crowns of extracted third molars were removed and post preparation was carried out with parapost drills (diameter 1.5 mm). After application of bonding agents individually formed FRC posts (everStick POST, diameter 1.5 mm) were cemented into the post spaces with either ParaCem®Universal or self-adhesive RelyX™Unicem, using two different cementation techniques: 1) an “indirect (traditional) technique” where the post was prepolymerized prior application of luting cement and insertion into the post space or 2) a “direct technique” where the uncured post was inserted to the post space with luting cement and light-polymerized in situ at the same time. After water storage of 48 hours, the roots (n = 10/group) were cut into discs of thickness of 2 mm. A push-out force was applied until specimen fracture or loosening of the post. A microleakage test was carried out on roots which were not subjected to the loading test (n= 32) to evaluate the sealing capacity of the post-canal interface. The microleakage was measured using dye penetration depth under a stereomicroscope. Results: Higher bond strength values (p<0.05) and less microleakage (p<0.05) were obtained with the “direct technique” compared to the “indirect technique”. None of the FRC posts revealed any dye penetration between the post and the cement. Conclusions: The “direct technique” seems to be beneficial when cementing individually formed FRC posts. PMID:23986792

Effect of temporary cements on the microtensile bond strength of self-etching and self-adhesive resin cement.

PubMed

Carvalho, Edilausson Moreno; Carvalho, Ceci Nunes; Loguercio, Alessandro Dourado; Lima, Darlon Martins; Bauer, José

2014-11-01

The aim of this study was to evaluate the microtensile bond strength (µTBS) of self-etching and self-adhesive resin cement systems to dentin affected by the presence of remnants of either eugenol-containing or eugenol-free temporary cements. Thirty extracted teeth were obtained and a flat dentin surface was exposed on each tooth. Acrylic blocks were fabricated and cemented either with one of two temporary cements, one zinc oxide eugenol (ZOE) and one eugenol free (ZOE-free), or without cement (control). After cementation, specimens were stored in water at 37°C for 1 week. The restorations and remnants of temporary cements were removed and dentin surfaces were cleaned with pumice. Resin composite blocks were cemented to the bonded dentin surfaces with one of two resin cements, either self-etching (Panavia F 2.0) or self-adhesive (RelyX U-100). After 24 h, the specimens were sectioned to obtain beams for submission to µTBS. The fracture mode was evaluated under a stereoscopic loupe and a scanning electron microscope (SEM). Data from µTBS were submitted to two-way repeated-measure ANOVA and the Tukey test (alpha = 0.05). The cross-product interaction was statistically significant (p < 0.0003). The presence of temporary cements reduced the bond strength to Panavia self-etching resin cements only (p < 0.05). Fracture occurred predominantly at the dentin-adhesive interface. The presence of eugenol-containing temporary cements did not interfere in the bond strength to dentin of self-adhesive resin cements.

Influence of airborne-particle abrasion on mechanical properties and bond strength of carbon/epoxy and glass/bis-GMA fiber-reinforced resin posts.

PubMed

Soares, Carlos Jose; Santana, Fernanda Ribeiro; Pereira, Janaina Carla; Araujo, Tatiana Santos; Menezes, Murilo Souza

2008-06-01

Controversy exists concerning the use of fiber-reinforced posts to improve bond strength to resin cement because some precementation treatments can compromise the mechanical properties of the posts. The purpose of this study was to analyze the influence of airborne-particle abrasion on the mechanical properties and microtensile bond strength (MTBS) of carbon/epoxy and glass/bis-GMA fiber-reinforced resin posts. Flexural strength (delta(f)), flexural modulus (E(f)), and stiffness (S) were assessed using a 3-point bending test for glass fiber-reinforced and carbon fiber-reinforced resin posts submitted to airborne-particle abrasion (AB) with 50-microm Al(2)O(3), and for posts without any surface treatment (controls) (n=10). Forty glass fiber (GF) and 40 carbon fiber (CF) posts were submitted to 1 of 4 surface treatments (n=10) prior to MTBS testing: silane (S); silane and adhesive (SA); airborne-particle abrasion with 50-microm Al(2)O(3) and silane (ABS); airborne-particle abrasion, silane, and adhesive (ABSA). Two composite resin restorations (Filtek Z250) with rounded depressions in the lateral face were bilaterally fixed to the post with resin cement (RelyX ARC). Next, the specimen was sectioned with a precision saw running perpendicular to the bonded surface to obtain 10 bonded beam specimens with a cross-sectional area of 1 mm(2). Each beam specimen was tested in a mechanical testing machine (EMIC 2,000 DL), under stress, at a crosshead speed of 0.5 mm/min until failure. Data were analyzed by 2-way ANOVA followed by Tukey HSD test (alpha=.05). Failure patterns of tested specimens were analyzed using scanning electron microscopy (SEM). The 3-point bending test demonstrated significant differences among groups only for the post type factor for flexural strength, flexural modulus, and stiffness. The carbon fiber posts exhibited significantly higher mean flexural strength (P=.001), flexural modulus (P=.003), and stiffness (P=.001) values when compared with glass fiber posts, irrespective of surface treatment. An alteration in the superficial structure of the posts could be observed by SEM after airborne-particle abrasion. MTBS testing showed no significant effect for the surface treatment type; however, significant effects for post system factor and for interaction between the 2 factors were observed. For the carbon fiber post, the ABSA surface treatment resulted in values significantly lower than the S surface treatment. SEM analysis of MTBS-tested specimens demonstrated adhesive and cohesive failures. Airborne-particle abrasion did not influence the mechanical properties of the post; however, it produced undesirable surface changes, which could reduce the bond strength to resin cement. For the surface treatments studied, if silane is applied, the adhesive system and airborne-particle abrasion are not necessary.

Degree of conversion and bond strength of resin-cements to feldspathic ceramic using different curing modes.

PubMed

Novais, Veridiana Resende; Raposo, Luís Henrique Araújo; Miranda, Rafael Resende de; Lopes, Camila de Carvalho Almança; Simamoto, Paulo Cézar; Soares, Carlos José

2017-01-01

The aim of this study was to assess the performance of resin cements when different curing modes are used, by evaluating the degree of conversion and bond strength to a ceramic substrate. Three resin cements were evaluated, two dual-cured (Variolink II and RelyX ARC) and one light-cured (Variolink Veneer). The dual-cured resin cements were tested by using the dual activation mode (base and catalyst) and light-activation mode (base paste only). For degree of conversion (DC) (n=5), a 1.0 mm thick feldspathic ceramic disc was placed over the resin cement specimens and the set was light activated with a QTH unit. After 24 h storage, the DC was measured with Fourier transform infrared spectroscopy (FTIR). For microshear bond strength testing, five feldspathic ceramic discs were submitted to surface treatment, and three cylindrical resin cement specimens were bonded to each ceramic surface according to the experimental groups. After 24 h, microshear bond testing was performed at 0.5 mm/min crosshead speed until the failure. Data were submitted to one-way ANOVA followed by Tukey test (p<0.05). Scanning electron microscopy (SEM) was used for classifying the failure modes. Higher DC and bond strength values were shown by the resin cements cured by using the dual activation mode. The Variolink II group presented higher DC and bond strength values when using light-activation only when compared with the Variolink Veneer group. The base paste of dual-cured resin cements in light-activation mode can be used for bonding translucent ceramic restorations of up to or less than 1.0 mm thick.

Light Transmission of Novel CAD/CAM Materials and Their Influence on the Degree of Conversion of a Dual-curing Resin Cement.

PubMed

Egilmez, Ferhan; Ergun, Gulfem; Cekic-Nagas, Isil; Vallittu, Pekka K; Lassila, Lippo V J

To evaluate the light transmission characteristics of different types, shades, and thicknesses of novel CAD/CAM materials and their effect on the degree of conversion (DC) of a dual-curing resin cement. Square specimens (12 × 12 mm2) of three CAD/CAM materials - GC Cerasmart, Lava Ultimate, Vita Enamic - of different thicknesses (1.00, 1.50, and 2.00 mm, n = 5 per thickness) were irradiated with an LED unit. The amount of transmitted light was quantified. Thereafter, the DC% of the dual-curing resin cement (RelyX Ultimate) was recorded after 15 min using Fourier transform infrared spectroscopy. Statistical analysis was performed using two-way ANOVA followed by the Tukey's HSD post-hoc test at a significance level of p < 0.05. Regression analysis was performed to investigate the correlation between the DC and radiant energy, and the DC and thickness. Although the type and shade of CAD/CAM material significantly affect transmitted light irradiation (p < 0.0001), degrees of conversion are similar when the CAD/CAM material or material shade were taken into consideration (p > 0.05). Conversely, material thickness significantly affected light transmission (p < 0.0001) and DC (p < 0.0001). Multiple effects of material, shade, and thickness did not significantly affect the evaluated parameters (p = 0.638 for light irradiation; p = 0.637 for DC). Linear regression analysis showed a correlation between delivered energy and DC% results of the Vita Enamic (R² = 0.4169, p < 0.0001). Reduced light transmission in 2-mm-thick specimens of all CAD/CAM materials indicates that proper curing of the cement beneath CAD/CAM materials should be ensured.

Assessing Leader Cognitive Skills with Situational Judgment Tests: Construct Validity Results

DTIC Science & Technology

2010-09-01

M2A1, M2A3 , M2A4a, M2A4b, M2A4e, M2A4k .54** Factor 5 (5 items): Mission Statement M3Ba, M3Bb, M3Bc, M3Bd, M3Be .33** Factor 6 (11 items): Mission...Organization. Team A 2/A/4-99 AR ( M2A3 ) 3/A/4-99 AR ( M2A3 ) 1/C/4-99 AR (M1A2 SEP) TF Control Scout Platoon Mortar Platoon 1/A/2-244 CHEM...SMK) (DS) B/1st BSB (OPCON) Maintenance Platoon Team B 2/B/4-99 AR ( M2A3 ) 3/B/4-99 AR ( M2A3 ) 1/DC/4-99 AR (M1A2 SEP) Team C 1

Phospholipase C-independent effects of 3M3FBS in murine colon.

PubMed

Dwyer, Laura; Kim, Hyun Jin; Koh, Byoung Ho; Koh, Sang Don

2010-02-25

The muscarinic receptor subtype M(3) is coupled to Gq/11 proteins. Muscarinic receptor agonists such as carbachol stimulate these receptors that result in activation of phospholipase C (PLC) which hydrolyzes phosphatidylinositol 4,5-bisphosphate into diacylglycerol and Ins(1,4,5)P(3). This pathway leads to excitation and smooth muscle contraction. In this study the PLC agonist, 2, 4, 6-trimethyl-N-(meta-3-trifluoromethyl-phenyl)-benezenesulfonamide (m-3M3FBS), was used to investigate whether direct PLC activation mimics carbachol-induced excitation. We examined the effects of m-3M3FBS and 2, 4, 6-trimethyl-N-(ortho-3-trifluoromethyl-phenyl)-benzenesulfonamide (o-3M3FBS), on murine colonic smooth muscle tissue and cells by performing conventional microelectrode recordings, isometric force measurements and patch clamp experiments. Application of m-3M3FBS decreased spontaneous contractility in murine colonic smooth muscle without affecting the resting membrane potential. Patch clamp studies revealed that delayed rectifier K(+) channels were reversibly inhibited by m-3M3FBS and o-3M3FBS. The PLC inhibitor, 1-(6-((17b-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione (U73122), did not prevent this inhibition by m-3M3FBS. Both m-3M3FBS and o-3M3FBS decreased two components of delayed rectifier K(+) currents in the presence of tetraethylammonium chloride or 4-aminopyridine. Ca(2+) currents were significantly suppressed by m-3M3FBS and o-3M3FBS with a simultaneous increase in intracellular Ca(2+). Pretreatment with U73122 did not prevent the decrease in Ca(2+) currents upon m-3M3FBS application. In conclusion, both m-3M3FBS and o-3M3FBS inhibit inward and outward currents via mechanisms independent of PLC acting in an antagonistic manner. In contrast, both compounds also caused an increase in [Ca(2+)](i) in an agonistic manner. Therefore caution must be employed when interpreting their effects at the tissue and cellular level.

Structural stability, dynamical stability, thermoelectric properties, and elastic properties of GeTe at high pressure

NASA Astrophysics Data System (ADS)

Kagdada, Hardik L.; Jha, Prafulla K.; Śpiewak, Piotr; Kurzydłowski, Krzysztof J.

2018-04-01

The stability of GeTe in rhombohedral (R 3 m ), face centred cubic (F m 3 m ), and simple cubic (P m 3 m ) phases has been studied using density functional perturbation theory. The rhombohedral phase of GeTe is dynamically stable at 0 GPa, while F m 3 m and P m 3 m phases are stable at 3.1 and 33 GPa, respectively. The pressure-dependent phonon modes are observed in F m 3 m and P m 3 m phases at Γ and M points, respectively. The electronic and the thermoelectric properties have been investigated for the stable phases of GeTe. The electronic band gap for rhombohedral and F m 3 m phases of GeTe has been observed as 0.66 and 0.17 eV, respectively, while the P m 3 m phase shows metallic behavior. We have used the Boltzmann transport equation under a rigid band approximation and constant relaxation time approximation as implemented in boltztrap code for the calculation of thermoelectric properties of GeTe. The metallic behavior of P m 3 m phase gives a very low value of Seebeck coefficient compared to the other two phases as a function of temperature and the chemical potential μ. It is observed that the rhombohedral phase of GeTe exhibits higher thermoelectric performance. Due to the metallic nature of P m 3 m phase, negligible thermoelectric performance is observed compared to R 3 m and F m 3 m -GeTe. The calculated lattice thermal conductivities are low for F m 3 m -GeTe and high for R 3 m -GeTe. At the relatively higher temperature of 1350 K, the figure of merit ZT is found to be 0.7 for rhombohedral GeTe. The elastic constants satisfy the Born stability criteria for all three phases. The rhombohedral and F m 3 m phases exhibits brittleness and the P m 3 m phase shows ductile nature.

[Effects of nitrogen-supply levels on leaf senescence and characteristics of distribution and utilization of 13C and 15N in Fuji 3 apple grafted on different stocks].

PubMed

Chen, Qian; Ding, Ning; Zhu, Zhan Ling; Peng, Ling; Ge, Shun Feng; Jiang, Yuan Mao

2017-07-18

Two-year-old potted Fuji 3 apple trees on different rootstocks [Fuji 3/M. micromalus Makin (joe), Fuji 3/M7 (semi-dwarf) and Fuji 3/M26/M. micromalus Makin (dwarf)] were used to study leaf morphology and photosynthesis and the characteristics of distribution and utilization of 13 C and 15 N at different nitrogen supply levels (0N, 25%N and 100%N, the N content in 100% N treatment was the same as that in Hoagland complete nutrient solution) under sand culture condition. The main results were as follows: At shoot growth cessation stage in autumn, the leaf chlorophyll content (SPAD), leaf nitrogen content and photosynthetic rate were found the highest in Fuji 3/M. micromalus Makin, followed by Fuji 3/M7, and the lowest was found in Fuji 3/M26/M. micromalus Makin under the same nitrogen stress treatments (0N and 25%N), however, under normal nitrogen treatment (100%N) Fuji 3/M26/M. micromalus Makin had the highest leaf SPAD value, photosynthetic rate and the nitrogen content, followed by Fuji 3/M7, and the lowest was found in Fuji 3/M. micromalus Makin. The leaf SOD and CAT activities showed Fuji 3/M. micromalus Makin > Fuji 3/M7 > Fuji 3/M26/M. micromalus Makin under the same nitrogen stress treatments, but showed Fuji 3/M26/M. micromalus Makin > Fuji 3/M7 > Fuji 3/M. micromalus Makin under the normal nitrogen treatment. There were significant differences in the distributions of 15 N and 13 C in root and leaf in the 3 scion-stock combinations, and the distribution rates of 15 N and 13 C in roots were the highest under nitrogen stress treatments and in the order of Fuji 3/M. micromalus Makin > Fuji 3/M7 > Fuji 3/M26/M. micromalus Makin. The distribution rates of 15 N and 13 C in leaves were the highest under the normal nitrogen treatment and in the order of Fuji 3/M26/M. micromalus Makin > Fuji 3/M7 > Fuji 3/M. micromalus Makin. The 15 N utilization ratio differed significantly among the 3 scion-stock combinations under different nitrogen application levels and was in the order of Fuji 3/M. micromalus Makin (44.3%, 37.5% and 31.4%)> Fuji 3/M7 (38.8%,30.7% and 26.6%) > Fuji 3/M26/M. micromalus Makin (32.0%,27.2% and 22.5%).

Theoretical descriptions of novel triplet germylenes M1-Ge-M2-M3 (M1 = H, Li, Na, K; M2 = Be, Mg, Ca; M3 = H, F, Cl, Br).

PubMed

Kassaee, Mohamad Zaman; Ashenagar, Samaneh

2018-02-06

In a quest to identify new ground-state triplet germylenes, the stabilities (singlet-triplet energy differences, ΔE S-T ) of 96 singlet (s) and triplet (t) M 1 -Ge-M 2 -M 3 species were compared and contrasted at the B3LYP/6-311++G**, QCISD(T)/6-311++G**, and CCSD(T)/6-311++G** levels of theory (M 1  = H, Li, Na, K; M 2  = Be, Mg, Ca; M 3  = H, F, Cl, Br). Interestingly, F-substituent triplet germylenes (M 3  = F) appear to be more stable and linear than the corresponding Cl- or Br-substituent triplet germylenes (M 3  = Cl or Br). Triplets with M 1  = K (i.e., the K-Ge-M 2 -M 3 series) seem to be more stable than the corresponding triplets with M 1  = H, Li, or Na. This can be attributed to the higher electropositivity of potassium. Triplet species with M 3  = Cl behave similarly to those with M 3  = Br. Conversely, triplets with M 3  = H show similar stabilities and linearities to those with M 3  = F. Singlet species of formulae K-Ge-Ca-Cl and K-Ge-Ca-Br form unexpected cyclic structures. Finally, the triplet germylenes M 1 -Ge-M 2 -M 3 become more stable as the electropositivities of the α-substituents (M 1 and M 2 ) and the electronegativity of the β-substituent (M 3 ) increase.

Novel 99mTc(III)-azide complexes [99mTc(N3)(CDO)(CDOH)2B-R] (CDOH2=cyclohexanedione dioxime) as potential radiotracers for heart imaging.

PubMed

Liu, Min; Zheng, Yumin; Avcibasi, Ugur; Liu, Shuang

2016-11-01

In this study, novel 99m Tc(III)-azide complexes [ 99m Tc(N 3 )(CDO)(CDOH) 2 B-R] ( 99m Tc-ISboroxime-N 3 : R=IS; 99m Tc-MPboroxime-N 3 : R=MP; 99m Tc-PAboroxime-N 3 : R=PA; 99m Tc-PYboroxime-N 3 : R=PY; and 99m Tc-Uboroxime-N 3 : R=5U) were evaluated as heart imaging agents. Complexes [ 99m Tc(N 3 )(CDO)(CDOH) 2 B-R] (R=IS, MP, PA, PY and 5U) were prepared by ligand exchange between NaN 3 and [ 99m TcCl(CDO)(CDOH) 2 B-R]. Biodistribution and imaging studies were carried out in Sprague-Dawley rats. Image quantification was performed to compare their initial heart uptake and myocardial retention. 99m Tc-ISboroxime-N 3 , 99m Tc-PYboroxime-N 3 and 99m Tc-Uboroxime-N 3 were prepared with high RCP (93-98%) while the RCP of 99m Tc-MPboroxime-N 3 and 99m Tc-PAboroxime-N 3 was 80-85%. The myocardial retention curves of 99m Tc-ISboroxime-N 3 , 99m Tc-PYboroxime-N 3 and 99m Tc-Uboroxime-N 3 were best fitted to the bi-exponential decay function. The half-time of the fast component was 1.6±0.4min for 99m Tc-ISboroxime-N 3 , 0.7±0.1min for 99m Tc-PYboroxime-N 3 and 0.9±0.4min for 99m Tc-Uboroxime-N 3 . The 2-min heart uptake from biodistribution studies followed the ranking order of 99m Tc-ISboroxime-N 3 (3.60±0.68%ID/g)> 99m Tc-PYboroxime-N 3 (2.35±0.37%ID/g)≫ 99m Tc-Uboroxime-N 3 (1.29±0.06%ID/g). 99m Tc-ISboroxime-N 3 had the highest 2-min heart uptake among 99m Tc radiotracers revaluated in SD rats. High quality SPECT images were obtained with the right and left ventricular walls being clearly delineated. The best image acquisition window was 0-5min for 99m Tc-ISboroxime-N 3 . Both azide coligand and boronate caps had significant impact on the heart uptake and myocardial retention of complexes [ 99m Tc(N 3 )(CDO)(CDOH) 2 B-R]. Among the radiotracers evaluated in SD rats, 99m Tc-ISboroxime-N 3 has the highest initial heart uptake with the heart retention comparable to that of 99m Tc-Teboroxime. 99m Tc-ISboroxime-N 3 is a promising alternative to 99m Tc-Teboroxime for SPECT MPI. Copyright © 2016 Elsevier Inc. All rights reserved.

Presynaptic mGlu1 and mGlu5 autoreceptors facilitate glutamate exocytosis from mouse cortical nerve endings.

PubMed

Musante, Veronica; Neri, Elisa; Feligioni, Marco; Puliti, Aldamaria; Pedrazzi, Marco; Conti, Valerio; Usai, Cesare; Diaspro, Alberto; Ravazzolo, Roberto; Henley, Jeremy M; Battaglia, Giuseppe; Pittaluga, Anna

2008-09-01

The effects of mGlu1 and mGlu5 receptor activation on the depolarization-evoked release of [3H]d-aspartate ([3H]D-ASP) from mouse cortical synaptosomes were investigated. The mGlu1/5 receptor agonist 3,5-DHPG (0.1-100microM) potentiated the K+(12mM)-evoked [3H]D-ASP overflow. The potentiation occurred in a concentration-dependent manner showing a biphasic pattern. The agonist potentiated [3H]D-ASP exocytosis when applied at 0.3microM; the efficacy of 3,5-DHPG then rapidly declined and reappeared at 30-100microM. The fall of efficacy of agonist at intermediate concentration may be consistent with 3,5-DHPG-induced receptor desensitization. Facilitation of [3H]D-ASP exocytosis caused by 0.3microM 3,5-DHPG was prevented by the selective mGlu5 receptor antagonist MPEP, but was insensitive to the selective mGlu1 receptor antagonist CPCCOEt. In contrast, CPCCOEt prevented the potentiation by 50microM 3,5-DHPG, while MPEP had minimal effect. Unexpectedly, LY 367385 antagonized both the 3,5-DHPG-induced effects. A total of 0.3microM 3,5-DHPG failed to facilitate the K+-evoked [3H]D-ASP overflow from mGlu5 receptor knockout (mGlu5-/-) cortical synaptosomes, but not from nerve terminals prepared from the cortex of animals lacking the mGlu1 receptors, the crv4/crv4 mice. On the contrary, 50microM 3,5-DHPG failed to affect the [3H]D-ASP exocytosis from cortical synaptosomes obtained from crv4/crv4 and mGlu5-/-mice. Western blot analyses in subsynaptic fractions support the existence of both mGlu1 and mGlu5 autoreceptors located presynaptically, while immunocytochemistry revealed their presence at glutamatergic terminals. We propose that mGlu1 and mGlu5 autoreceptors exist on mouse glutamatergic cortical terminals; mGlu5 receptors may represent the "high affinity" binding sites for 3,5-DHPG, while mGlu1 autoreceptors represent the "low affinity" binding sites.

PEO GCS Portfolio Overview

DTIC Science & Technology

2012-08-14

Long Term (2035) M2A3 IFV M113 FOV M1A2 SEPv2 Bradley A3 Non-IFV: -M3A3 Cav Fighting Veh -M7A3 BFIST Bradley A2 Non-IFV: -M2A2 ODS-E Stryker...GCV – IFV AMPV FoV GCV – IFV M2A3 IFV M113 FOV M109A6 M1A2 SEPv2 ECP1 Future Howitzer ? Future Tank? Future Modernization? DVH Future

Air quality status during Diwali festival of India: a case study.

PubMed

Rao, Padma S; Gajghate, D G; Gavane, A G; Suryawanshi, P; Chauhan, C; Mishra, S; Gupta, N; Rao, C V C; Wate, S R

2012-08-01

The PM(2.5) and PM(10) samples were collected during Diwali celebration from study area and characterized for ionic concentration of four anions (NO(3) (-), NO(2) (-), Cl(-), SO(4) (2-)) and five cations (K(+), Mg(2+), NH(4) (+), Ca(2+), Na(+)). The results showed that the ionic concentrations were three times compared to those on pre and post Diwali days. Predominant ions for PM(2.5) were K(+) 33.7 μg/m(3), Mg(+) 31.6 μg/m(3), SO(4) (2-) 22.1 μg/m(3), NH(4) (+) 17.5 μg/m(3) and NO(3) (-) 18 μg/m(3) and for PM(10) the ionic concentrations were Mg(+) 29.6 μg/m(3), K(+) 26 μg/m(3), SO(4) (2-) 19.9 μg/m(3), NH(4) (+) 16.8 μg/m(3) and NO(3) (-) 16 μg/m(3). While concentration of SO(2) and NO(2) were 17.23, 70.33 μg/m(3) respectively.

Search for compounds contributing to onion-like off-flavor in beer and investigation of the cause of the flavor.

PubMed

Noba, Shigekuni; Yako, Nana; Kobayashi, Minoru; Masuda, Susumu; Watanabe, Tetsuya

2017-10-01

Onion-like off-flavor is a highly undesirable property in beer. Although several compounds that impart onion-like odors have been identified, the individual contribution of these compounds to the onion-like off-flavor in beer is not clear. In the present study, we searched for compounds that impart an onion-like odor by gas chromatography (GC)-olfactometry. The analysis of several types of beer revealed that 2-mercapto-3-methyl-1-butanol (2M3MB) and 3-mercapto-3-methyl-1-butanol (3M3MB) were possible causative compounds. Based on the difference threshold values in beer (0.13 ng/mL for 2M3MB and 17.5 ng/mL for 3M3MB) and the quantification values of these compounds in beer samples, only 2M3MB was considered to contribute to the onion-like off-flavor in beer. A further formation factor analysis of 2M3MB revealed that 2M3MB was formed in hopped wort after fermentation, and that the concentration of 2M3MB increased following the hot aeration treatment of wort. These results suggest that preventing the hot aeration of wort is a key factor for reducing 2M3MB levels in beer. In a previous report, 3-methyl-2-buten-1-ol (3MBol) was speculated to be the precursor of 2M3MB and 3M3MB; however, the results of the present quantification analysis and wort addition tests indicate that 3MBol did not contribute to the formation of 2M3MB in the brewing process and that unknown precursors of 2M3MB originated in wort. Identifying the precursor of 2M3MB may facilitate elucidation of the mechanism of 2M3MB formation. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Anti-M(3) muscarinic cholinergic autoantibodies from patients with primary Sjögren's syndrome trigger production of matrix metalloproteinase-3 (MMP-3) and prostaglandin E(2) (PGE(2)) from the submandibular glands.

PubMed

Reina, Silvia; Sterin-Borda, Leonor; Passafaro, Daniela; Borda, Enri

2011-05-01

We demonstrated that serum immunoglobulin G (IgG) from patients with primary Sjögren's syndrome (pSS), interacting with the second extracellular loop of human glandular M(3) muscarinic acetylcholine receptors (M(3) mAChR), trigger the production of matrix metalloproteinase-3 (MMP-3) and prostaglandin E(2) (PGE(2)). Enzyme-linked immunosorbent assays (ELISAs) were performed in the presence of M(3) mAChR synthetic peptide as antigen to detect in serum the autoantibodies. Further, MMP-3 and PGE(2) production were determined in the presence of anti-M(3) mAChR autoantibodies. An association was observed between serum and anti-M(3) mAChR autoantibodies and serum levels of MMP-3 and PGE(2) in pSS patients. Thus, we established that serum anti-M(3) mAChR autoantibodies, MMP-3 and PGE(2) may be considered to be early markers of pSS associated with inflammation. Affinity-purified anti-M(3) mAChR peptide IgG from pSS patients, whilst stimulating salivary-gland M(3) mAChR, causes an increase in the level of MMP-3 and PGE(2) as a result of the activation of phospholipase A(2) (PLA(2)) and cyclooxygenase-2 (COX-2) (but not COX-1). These results provide a novel insight into the role that cholinoceptor antibodies play in the development of glandular inflammation. This is the first report showing that an antibody interacting with glandular mAChR can induce the production of pro-inflammatory mediators (MMP-3/PGE(2)). Copyright © 2010 Elsevier Ltd. All rights reserved.

Metabolism of [6]-shogaol in mice and in cancer cells.

PubMed

Chen, Huadong; Lv, Lishuang; Soroka, Dominique; Warin, Renaud F; Parks, Tiffany A; Hu, Yuhui; Zhu, Yingdong; Chen, Xiaoxin; Sang, Shengmin

2012-04-01

Ginger has received extensive attention because of its antioxidant, anti-inflammatory, and antitumor activities. However, the metabolic fate of its major components is still unclear. In the present study, the metabolism of [6]-shogaol, one of the major active components in ginger, was examined for the first time in mice and in cancer cells. Thirteen metabolites were detected and identified, seven of which were purified from fecal samples collected from [6]-shogaol-treated mice. Their structures were elucidated as 1-(4'-hydroxy-3'-methoxyphenyl)-4-decen-3-ol (M6), 5-methoxy-1-(4'-hydroxy-3'-methoxyphenyl)-decan-3-one (M7), 3',4'-dihydroxyphenyl-decan-3-one (M8), 1-(4'-hydroxy-3'-methoxyphenyl)-decan-3-ol (M9), 5-methylthio-1-(4'-hydroxy-3'-methoxyphenyl)-decan-3-one (M10), 1-(4'-hydroxy-3'-methoxyphenyl)-decan-3-one (M11), and 5-methylthio-1-(4'-hydroxy-3'-methoxyphenyl)-decan-3-ol (M12) on the basis of detailed analysis of their (1)H, (13)C, and two-dimensional NMR data. The rest of the metabolites were identified as 5-cysteinyl-M6 (M1), 5-cysteinyl-[6]-shogaol (M2), 5-cysteinylglycinyl-M6 (M3), 5-N-acetylcysteinyl-M6 (M4), 5-N-acetylcysteinyl-[6]-shogaol (M5), and 5-glutathiol-[6]-shogaol (M13) by analysis of the MS(n) (n = 1-3) spectra and comparison to authentic standards. Among the metabolites, M1 through M5, M10, M12, and M13 were identified as the thiol conjugates of [6]-shogaol and its metabolite M6. M9 and M11 were identified as the major metabolites in four different cancer cell lines (HCT-116, HT-29, H-1299, and CL-13), and M13 was detected as a major metabolite in HCT-116 human colon cancer cells. We further showed that M9 and M11 are bioactive compounds that can inhibit cancer cell growth and induce apoptosis in human cancer cells. Our results suggest that 1) [6]-shogaol is extensively metabolized in these two models, 2) its metabolites are bioactive compounds, and 3) the mercapturic acid pathway is one of the major biotransformation pathways of [6]-shogaol.

Metabolism of [6]-Shogaol in Mice and in Cancer Cells

PubMed Central

Chen, Huadong; Lv, Lishuang; Soroka, Dominique; Warin, Renaud F.; Parks, Tiffany A.; Hu, Yuhui; Zhu, Yingdong; Chen, Xiaoxin

2012-01-01

Ginger has received extensive attention because of its antioxidant, anti-inflammatory, and antitumor activities. However, the metabolic fate of its major components is still unclear. In the present study, the metabolism of [6]-shogaol, one of the major active components in ginger, was examined for the first time in mice and in cancer cells. Thirteen metabolites were detected and identified, seven of which were purified from fecal samples collected from [6]-shogaol-treated mice. Their structures were elucidated as 1-(4′-hydroxy-3′-methoxyphenyl)-4-decen-3-ol (M6), 5-methoxy-1-(4′-hydroxy-3′-methoxyphenyl)-decan-3-one (M7), 3′,4′-dihydroxyphenyl-decan-3-one (M8), 1-(4′-hydroxy-3′-methoxyphenyl)-decan-3-ol (M9), 5-methylthio-1-(4′-hydroxy-3′-methoxyphenyl)-decan-3-one (M10), 1-(4′-hydroxy-3′-methoxyphenyl)-decan-3-one (M11), and 5-methylthio-1-(4′-hydroxy-3′-methoxyphenyl)-decan-3-ol (M12) on the basis of detailed analysis of their 1H, 13C, and two-dimensional NMR data. The rest of the metabolites were identified as 5-cysteinyl-M6 (M1), 5-cysteinyl-[6]-shogaol (M2), 5-cysteinylglycinyl-M6 (M3), 5-N-acetylcysteinyl-M6 (M4), 5-N-acetylcysteinyl-[6]-shogaol (M5), and 5-glutathiol-[6]-shogaol (M13) by analysis of the MSn (n = 1–3) spectra and comparison to authentic standards. Among the metabolites, M1 through M5, M10, M12, and M13 were identified as the thiol conjugates of [6]-shogaol and its metabolite M6. M9 and M11 were identified as the major metabolites in four different cancer cell lines (HCT-116, HT-29, H-1299, and CL-13), and M13 was detected as a major metabolite in HCT-116 human colon cancer cells. We further showed that M9 and M11 are bioactive compounds that can inhibit cancer cell growth and induce apoptosis in human cancer cells. Our results suggest that 1) [6]-shogaol is extensively metabolized in these two models, 2) its metabolites are bioactive compounds, and 3) the mercapturic acid pathway is one of the major biotransformation pathways of [6]-shogaol. PMID:22246389

Implementing Material Surfaces with an Adhesive Switch

DTIC Science & Technology

2014-02-28

squares), M15 (solid triangles), M13 (open circles), M11 (solid circles), or NC14 (open triangles) DNA primary targets. Error bars indicating...5’–ATCAGGCGCAA–3’ M13 = 5’–ATCAGCGGCAATC–3’ M15 = 5’–ATCAGCCCCAATCCA–3’ L3M9 = 5’–ATLCACLCCGLC–3’ L3M11 = 5

Probing the binding of cationic lipids with dendrimers.

PubMed

Mandeville, J S; Bourassa, P; Tajmir-Riahi, H A

2013-01-14

Polycationic polymers are used extensively in biology to disrupt cell membranes and thus enhance the transport of materials into the cell. We report the bindings of several lipids cholesterol (Chol), 1,2-dioleoyl-3-trimethylammonium-propane(DOTAP), dioctadecyldimethylammoniumbromide (DDAB), and dioleoylphosphatidylethanolamine (DOPE) to dendrimers of different compositions such as mPEG-PAMAM (G3), mPEG-PAMAM (G4), and PAMAM (G4) under physiological conditions. FTIR, UV-visible spectroscopic, methods and molecular modeling were used to analyze the lipid binding mode, the binding constant, and the effects of lipid complexation on the dendrimer structure. The structural analysis showed that lipids bind dendrimers through both hydrophilic and hydrophobic contacts with overall binding constants of K(chol-mPEG-G3) = 1.7 × 10(3) M(-1), K(chol-mPEG-PAMAM-G4) = 2.7 × 10(3) M(-1), K(chol-PAMAM-G4) = 1.0 × 10(3) M(-1), K(DOPE-mPEG-G3) = 1.5 × 10(3) M(-1), K(DOPE-mPEG-PAMAM-G4) = 1.6 × 10(3) M(-1), K(DOPE-PAMAM-G4) = 5.3 × 10(2) M(-1), K(DDAB-mPEG-G3) = 1.5 × 10(3) M(-1), K(DDAB-mPEG-PAMAM-G4) = 1.9 × 10(2) M(-1), K(DDAB-PAMAM-G4) = 7.0 × 10(2) M(-1), K(DOTAP-mPEG-G3) = 1.9 × 10(3) M(-1), K(DOTAP-mPEG-PAMAM-G4) = 1.5 × 10(3) M(-1), and K(DOTAP-PAMAM-G4) = 5.7 × 10(2) M(-1). Weaker interaction was observed as dendrimer cationic charges increased. The free binding energies from docking were -5.15 (cholesterol), -5.79 (DDAB), and -5.36 kcal/mol (DOTAP) with the order of stability DDAB-PAMAM-G-4 > DOTAP-PAMAM-G4 > cholesterol-PAMAM-G4, consistent with the spectroscopic results. Dendrimers might act as carriers to transport lipids in vitro.

Roles for N-terminal Extracellular Domains of Nicotinic Acetylcholine Receptor (nAChR) β3 Subunits in Enhanced Functional Expression of Mouse α6β2β3- and α6β4β3-nAChRs*

PubMed Central

Dash, Bhagirathi; Li, Ming D.; Lukas, Ronald J.

2014-01-01

Functional heterologous expression of naturally expressed mouse α6*-nicotinic acetylcholine receptors (mα6*-nAChRs; where “*” indicates the presence of additional subunits) has been difficult. Here we expressed and characterized wild-type (WT), gain-of-function, chimeric, or gain-of-function chimeric nAChR subunits, sometimes as hybrid nAChRs containing both human (h) and mouse (m) subunits, in Xenopus oocytes. Hybrid mα6mβ4hβ3- (∼5–8-fold) or WT mα6mβ4mβ3-nAChRs (∼2-fold) yielded higher function than mα6mβ4-nAChRs. Function was not detected when mα6 and mβ2 subunits were expressed together or in the additional presence of hβ3 or mβ3 subunits. However, function emerged upon expression of mα6mβ2mβ3V9′S-nAChRs containing β3 subunits having gain-of-function V9′S (valine to serine at the 9′-position) mutations in transmembrane domain II and was further elevated 9-fold when hβ3V9′S subunits were substituted for mβ3V9′S subunits. Studies involving WT or gain-of-function chimeric mouse/human β3 subunits narrowed the search for domains that influence functional expression of mα6*-nAChRs. Using hβ3 subunits as templates for site-directed mutagenesis studies, substitution with mβ3 subunit residues in extracellular N-terminal domain loops “C” (Glu221 and Phe223), “E” (Ser144 and Ser148), and “β2-β3” (Gln94 and Glu101) increased function of mα6mβ2*- (∼2–3-fold) or mα6mβ4* (∼2–4-fold)-nAChRs. EC50 values for nicotine acting at mα6mβ4*-nAChR were unaffected by β3 subunit residue substitutions in loop C or E. Thus, amino acid residues located in primary (loop C) or complementary (loops β2-β3 and E) interfaces of β3 subunits are some of the molecular impediments for functional expression of mα6mβ2β3- or mα6mβ4β3-nAChRs. PMID:25028511

Continuous release of interleukin 12 from microencapsulated engineered cells for colon cancer therapy

PubMed Central

Zheng, Shu; Xiao, Zuo-Xiang; Pan, Yue-Long; Han, Ming-Yong; Dong, Qi

2003-01-01

AIM: To explore the anti-tumor immunity against CT26 colon tumor of the microencapsulated cells modified with murine interleukine-12 (mIL-12) gene. METHODS: Mouse fibroblasts (NIH3T3) were stably transfected to express mIL-12 using expression plasmids carrying mIL-12 gene (p35 and p40), and NIH3T3-mIL-12 cells were encapsulated in alginate microcapsules for long-term delivery of mIL-12. mIL-12 released from the microencapsulated NIH3T3-mIL-12 cells was confirmed using ELISA assay. Transplantation of the microencapsulated NIH3T3-mIL-12 cells was performed in the tumor-bearing mice with CT26 cells. The anti-tumor responses and the anti-tumor activities of the microencapsulated NIH3T3-mIL-12 cells were evaluated. RESULTS: Microencapsulated NIH3T3-mIL-12 cells could release mIL-12 continuously and stably for a long time. After the microencapsulated NIH3T3-mIL-12 cells were transplanted subcutaneously into the tumor-bearing mice for 21 d, the serum concentrations of mIL-12, mIL-2 and mIFN-γ, the cytotoxicity of the CTL from the splenocytes and the NK activity in the treatment group were significantly higher than those in the controls. Moreover, mIL-12 released from the microencapsulated NIH3T3-mIL-12 cells resulted in a significant inhibition of tumor proliferation and a prolonged survival of tumor-bearing mice. CONCLUSION: The microencapsulated NIH3T3-mIL-12 cells have a significant therapeutic effect on the experimental colon tumor by activating anti-tumor immune responses in vivo. Microencapsulated and genetically engineered cells may be an extremely versatile tool for tumor gene therapy. PMID:12717836

Synthesis and characterisation of new Schiff base monomers containing N-(alkyl and phenyl) pyrrole moieties

NASA Astrophysics Data System (ADS)

Amer, Ahcene Ait; Ilikti, Hocine; Maschke, Ulrich

2017-11-01

This article deals with the synthesis and characterisation of seven new functional Schiff base monomers, such as: M1: 1-(3-Pyrrole-1-yl-propylimino-methyl)-naphtalen-2-ol; M2: 2-(3-Pyrrole-1-yl-phenylimino-methyl)-phenol; M3: 1-(3-Pyrrole-1-yl-phenylimino-methyl)-naphtalen-2-ol; M4: N-(pyridin-2-yl-methylene)-2-(pyrrol-1-yl)-benzenamine; M5: N-(pyridin-2-yl-methylene)-3-(pyrrol-1-yl)-propan-1-amine; M6: 2-(3-pyrrol-1-yl-propylimino-methyl)-quinolin-8-ol; M7: 2-(3-pyrrol-1-yl-phenylimino-methyl)-quinolin-8-ol. Two series of compounds emerged from this study, N-propyl pyrrole derivatives (M1, M5, M6) and N-phenyl pyrrole compounds (M2, M3, M4, M7). All monomers were elaborated by condensation reactions between appropriate amines and aldehydes, and their molecular structures were confirmed by spectroscopic analysis methods like FT-IR, 1H NMR, 13C NMR, and GC-MS.

Hypoglycemia and risk of seizures: a retrospective cross-sectional study.

PubMed

Imad, Halawa; Johan, Zelano; Eva, Kumlien

2015-02-01

Few studies have been dedicated to assess neurological symptoms in relations to hypoglycemia. In this study we investigated the association between different levels of hypoglycemia and the occurrence of epileptic seizures in patients without a prior diagnosis of epilepsy. A retrospective cross-sectional study. We identified 388 individuals from a laboratory database in Swedish regional hospital who had been found to have a glucose value of ≤3.5 mM between January and December 2009. Medical records were reviewed. Hypoglycemia was defined at three different categories: 0-2 mM (40 patients), 2.1-3 mM (154 patients) and 3.1-3.5 mM (194 patients). 14 patients had disturbance of consciousness including 3 with seizures. The majority of cases had coma, a generalized tonic-clonic seizure was seen only when s-glucose dropped below 2.0 mM. Two cases with focal seizure were noted, one at s-glucose 2.0 mM, and one at s-glucose 3.3 mM. The absolute risks (95% confidence interval) for having major neurological symptoms at glucose levels of ≤2.0 mM were 0.25 (0.13-0.41), 0.02 (0-0.06) at 2.1-3.0 mM and 0.01 (0-0.03) at 3.1-3.5 mM. Coma is the most common neurological symptom related to hypoglycemia. Epileptic seizures are rare and not as common as previously assumed. Copyright © 2014 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

Measurements of radon and thoron progeny concentrations in dwellings of Tehri Garhwal, India, using LR-115 deposition-based DTPS/DRPS technique.

PubMed

Prasad, Mukesh; Rawat, Mukesh; Dangwal, Anoop; Yadav, Manjulata; Gusain, G S; Mishra, Rosaline; Ramola, R C

2015-11-01

This paper presents the values of radon and thoron progeny concentrations for different seasons in the dwellings of Tehri Garhwal, India. The measurements have been carried out using LR-115 solid-state nuclear track detector-based passive time-integrated direct thoron progeny sensor/direct radon progeny sensor technique. In summer, the radon and thoron progeny have been found to vary from 5.7±0.8 to 153.2±4.3 Bq m(-3) with an average of 37.6 Bq m(-3) and 0.3±0.06 to 3.2±0.19 Bq m(-3) with an average of 1.3 Bq m(-3), respectively. In the rainy season, the radon and thoron progeny have been found to vary from 3.2±0.6 to 120±3.7 Bq m(-3) with an average of 58.2 Bq m(-3) and 0.2±0.05 to 11.3±0.37 Bq m(-3) with an average of 3.4 Bq m(-3), respectively. In autumn, the radon and thoron progeny have been found to vary from 4.1±0.7 to 374.4±6.7 Bq m(-3) with an average of 95.6 Bq m(-3) and from 0.3±0.06 to 30.5±0.60 Bq m(-3) with an average of 6.6 Bq m(-3), respectively. In winter, the radon and thoron progeny have been found to vary from 9.8±1.1 to 188.9±4.8 Bq m(-3) with an average of 70.7 Bq m(-3) and 0.1±0.03 to 7.5±0.30 Bq m(-3) with an average of 2.3 Bq m(-3), respectively. It has been observed that the average value of radon and thoron progeny concentrations is maximum for autumn and minimum for summer seasons. The seasonal variations in radon and thoron progeny concentrations in different houses are discussed in detail. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Theoretical study of 'Mixed' ligands superhalogens: Cl-M-NO3 (M = Li, Na, K)

NASA Astrophysics Data System (ADS)

Zhao, Xinghua; Liu, Weihui; Wang, Jiesheng; Li, Chun; Yuan, Guang

2016-08-01

MCl2-, M(NO3)2-, and (Cl-M-NO3)- (M = Li, Na, K) species are systematically investigated using the density functional theory. In all the cases studied, the vertical detachment energies (VDEs) exceed the electron affinity of chlorine atom, leading to the conclusion that MCl2-, M(NO3)2- and (Cl-M-NO3)- are superhalogens. The VDEs of (Cl-M-NO3)- are between that of MCl2- and M(NO3)2-, showing that replacing one ligand with a larger electronegative ligand leads to the higher VDE. Superhalogens with suitable VDEs can be built by using different ligands.

Generation and functional analysis of monoclonal antibodies against the second extracellular loop of human M3 muscarinic acetylcholine receptor.

PubMed

Tsuboi, Hiroto; Nakamura, Yumi; Iizuka, Mana; Matsuo, Naomi; Matsumoto, Isao; Sumida, Takayuki

2012-04-01

The M3 muscarinic acetylcholine receptor (M3R) plays a crucial role in the activation of salivary and lachrymal glands. The M3R contains four extracellular domains (the N-terminal, and the first, second, and third extracellular loops), and we recently detected antibodies against each of these four domains in a subgroup of patients with Sjögren's syndrome (SS). Functional analysis indicated that the influence of such anti-M3R antibodies on salivary secretion might differ based on the epitopes to which they bind. To clarify the relationship between B-cell epitopes on the M3R and its function, we generated two hybridomas producing anti-M3R monoclonal antibodies against the second extracellular loop of M3R (anti-M3R(2nd) mAbs) and analyzed their function by Ca(2+)-influx assays, using a human salivary gland (HSG) cell line. These two anti-M3R(2nd) mAbs suppressed Ca(2+)-influx in the HSG cells induced by cevimeline stimulation, suggesting that autoantibodies against the second extracellular loop of M3R could be involved in salivary dysfunction in patients with SS.

Naval Outgoing Message Processing, A Study of Message Generation and Message Preparation for Transmission and the Impact of Automation.

DTIC Science & Technology

1979-12-01

AM AM .m Itp 3MM"fvob 3MMopo" INA 7M 3M. St Z is pu~ e posep 3MM 3MMoar INA 3M 3MM St. 3M. Y" M3L-SINA1I 334IopAsoe * w*; INAt e M IM0NA .6.6.36...C or 20 ma current loop Current loop (60V. 60 ma) High level (±80V, 20 ma) INA Yes Yes Yes Same sIBM SELECTRIC Yes INA INA INA INA INA INA INA INA

The Armored Brigade Combat Team (ABCT) in the Future: An Assessment of Capabilities Against the Hybrid Threat in the Future Operational Environment

DTIC Science & Technology

2013-06-13

reconnaissance squadron costs. The ABCT was calculated based on two combined arms battalions and one reconnaissance squadron equipped with M2A3 /M3A3...ABCT Deployment Cost Data to the NTC SRC TITLE W_VEHICLES 06385R001 FIRES BN 155SP (HBCT) (M109A6) $712,009.00 07205R101 COMBINED ARMS BN ( M2A3 ...07205R101 COMBINED ARMS BN ( M2A3 /M3A3/M1A2) $503,852.00 17205R101 RECON SQUADRON (HBCT) (M3A3) $239,804.00 63325R001 BRIGADE SUPPORT BN (HBCT

Cascade Pumping of 1.9–3.3 μm Type-I Quantum Well GaSb-Based Diode Lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shterengas, Leon; Kipshidze, Gela; Hosoda, Takashi

Cascade pumping of type-I quantum well gain sections was utilized to increase output power and efficiency of GaSb-based diode lasers operating in spectral region from 1.9 to 3.3 μm. Coated devices with ~100-μm-wide aperture and 3-mm-long cavity demonstrated continuous wave (CW) output power of 1.96 W near 2 μm, 980 mW near 3 μm, 500 mW near 3.18 μm, and 360 mW near 3.25 μm at room temperature. The corresponding narrow ridge lasers with nearly diffraction limited beams operate in CW regime with tens of mW of output power up to 60 °C. Two step shallow/deep narrow/wide ridge waveguide devicesmore » showed lower threshold currents and higher slope efficiencies compared to single step narrow ridge lasers. Laterally coupled DFB lasers mounted epi-up generated above 10 mW of tunable single frequency CW power at 20 °C near 3.22 μm.« less

Cascade Pumping of 1.9–3.3 μm Type-I Quantum Well GaSb-Based Diode Lasers

DOE PAGES

Shterengas, Leon; Kipshidze, Gela; Hosoda, Takashi; ...

2017-03-24

Cascade pumping of type-I quantum well gain sections was utilized to increase output power and efficiency of GaSb-based diode lasers operating in spectral region from 1.9 to 3.3 μm. Coated devices with ~100-μm-wide aperture and 3-mm-long cavity demonstrated continuous wave (CW) output power of 1.96 W near 2 μm, 980 mW near 3 μm, 500 mW near 3.18 μm, and 360 mW near 3.25 μm at room temperature. The corresponding narrow ridge lasers with nearly diffraction limited beams operate in CW regime with tens of mW of output power up to 60 °C. Two step shallow/deep narrow/wide ridge waveguide devicesmore » showed lower threshold currents and higher slope efficiencies compared to single step narrow ridge lasers. Laterally coupled DFB lasers mounted epi-up generated above 10 mW of tunable single frequency CW power at 20 °C near 3.22 μm.« less

Enzymatic Conversion of Red Cells for Transfusion.

DTIC Science & Technology

1979-11-19

2 0 x( w m m w0 - 0 - - j to 3 >-4M m m Z 01 -4 -1 0 z 0 C< -< z z z m-0 r, 0 0 -" m 0 0 mu m -a > -4 m Lo m...q W >lM G)0 0- COO) ) vp 3 Z51 - - CO 2 - 0C 2 omz m zm > -nm~j m 0 w N4 0 ;o- 3 -42 m In Vm0 m mmc > -- 4 C, - -- 0 0 - 2 z C.. 2 m 0 > mff C) m --I ;K...6,11 NL Eu.. N3. r low I ,. 14.0. ~~I45 2 . 1.25 11 3.2 m,’ • .. .’ ’: MIRCP RESLIO N C AR .: S . , . II..1 %. I I" :I ’ 1 1 1 1

Validation of the 3M molecular detection system for the detection of listeria in meat, seafood, dairy, and retail environments.

PubMed

Fortes, Esther D; David, John; Koeritzer, Bob; Wiedmann, Martin

2013-05-01

There is a continued need to develop improved rapid methods for detection of foodborne pathogens. The aim of this project was to evaluate the 3M Molecular Detection System (3M MDS), which uses isothermal DNA amplification, and the 3M Molecular Detection Assay Listeria using environmental samples obtained from retail delicatessens and meat, seafood, and dairy processing plants. Environmental sponge samples were tested for Listeria with the 3M MDS after 22 and 48 h of enrichment in 3M Modified Listeria Recovery Broth (3M mLRB); enrichments were also used for cultural detection of Listeria spp. Among 391 samples tested for Listeria, 74 were positive by both the 3M MDS and the cultural method, 310 were negative by both methods, 2 were positive by the 3M MDS and negative by the cultural method, and one sample was negative by the 3M MDS and positive by the cultural method. Four samples were removed from the sample set, prior to statistical analyses, due to potential cross-contamination during testing. Listeria isolates from positive samples represented L. monocytogenes, L. innocua, L. welshimeri, and L. seeligeri. Overall, the 3M MDS and culture-based detection after enrichment in 3M mLRB did not differ significantly (P < 0.05) with regard to the number of positive samples, when chi-square analyses were performed for (i) number of positive samples after 22 h, (ii) number of positive samples after 48 h, and (iii) number of positive samples after 22 and/or 48 h of enrichment in 3M mLRB. Among 288 sampling sites that were tested with duplicate sponges, 67 each tested positive with the 3M MDS and the traditional U.S. Food and Drug Administration Bacteriological Analytical Manual method, further supporting that the 3M MDS performs equivalently to traditional methods when used with environmental sponge samples.

Block of high-threshold calcium channels by the synthetic polyamines sFTX-3.3 and FTX-3.3.

PubMed

Norris, T M; Moya, E; Blagbrough, I S; Adams, M E

1996-10-01

A polyamine component of Agelenopsis aperta spider venom designated FTX is reported to be a selective antagonist of P-type calcium channels in the mammalian brain. Consequently, this component has frequently been used as a pharmacological tool to determine the presence, distribution, and function of P-type channels in physiological systems. We describe antagonism of calcium channels by the synthesized polyamine FTX-3.3, which has the proposed structure of natural FTX. We also examined a corresponding polyamine amide, sFTX-3.3. These polyamines are critically evaluated for antagonism of three high-threshold calcium channel subtypes in rat neurons through the use of the whole-cell patch-clamp technique. FTX-3.3 (IC50 = approximately 0.13 mM) is approximately twice as potent as sFTX-3.3 (IC50 = approximately 0.24 mM) against P-type channels and approximately 3-fold more potent against N-type channels (FTX-3.3, IC50 = approximately 0.24 mM; sFTX-3.3, IC50 = approximately 0.70 mM). Both polyamines also block L-type calcium channels with similar potencies. sFTX-3.3 (1 mM) and FTX-3.3 (0.5 mM) typically block 50% and 65% of Bay K8644-enhanced L-type current, respectively. Antagonism of each calcium channel subtype is voltage dependent, with less inhibition of Ba2+ currents at more-positive potentials. These data show that both sFTX-3.3 and FTX-3.3 antagonize P-, N-, and L-type calcium channels in mammalian Purkinje and superior cervical ganglia neurons with similar IC50 values.

Safety Factor Analysis for Centrifuge Systems.

DTIC Science & Technology

1991-07-24

tonnes mass at up to 350g, and a 4 tonnes mass at up to 150g, on a 1.3 m x 1.3 m swinging platform. ANS&A recommends that the operations of this...counterweight, and a larger 1.6 m x 1.3 m swinging platform for tests of up to 3 tonnes mass at 200g and 6 tonnes at 100g are offered but should not be...optional prototype 350g platform 200g platform dimensions (l.3m x 1.3m) (l.6m xl.6m) and masses 2T 4T 3T 6T at 350g at 150g at 200g at 100g length (m

Ferroelectric and magnetic properties of Aurivillius Bi{sub m+1}Ti{sub 3}Fe{sub m−3}O{sub 3m+3} thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jia, Tingting, E-mail: jia.tingting@nims.go.jp; Kimura, Hideo, E-mail: KIMURA.Hideo@nims.go.jp; Cheng, Zhenxiang

2015-11-15

Aurivillius Bi{sub m+1}Ti{sub 3}Fe{sub m−3}O{sub 3m+3} (m = 4, 5, 6) thin films have been deposited by a pulsed laser deposition system. The x-ray diffraction patterns indicate the formation of orthorhombic phase. The remanent polarization (2P{sub r}) of Bi{sub m+1}Ti{sub 3}Fe{sub m−3}O{sub 3m+3} thin films is decreased with the m-number. Positive-up-negative-down measurements indicate the presence of ferroelectric (FE) polarization in as-obtained thin films. Piezoresponse force microscopy investigations confirm the existence of FE domains and the switchable polarization. Weak magnetic moment is detected in the Aurivillius films at room temperature. The present work suggests the possibility of Aurivillius Bi{sub m+1}Ti{sub 3}Fe{sub m−3}O{sub 3m+3}more » (m = 4, 5, 6) materials as potential room-temperature multiferroics.« less

Evaluation of ovotoxicity induced by 7, 12-dimethylbenz[a]anthracene and its 3,4-diol metabolite utilizing a rat in vitro ovarian culture system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Igawa, Yoshiyuki; BioPharma Center, Asubio Pharma Co., Ltd., Gunma; Keating, Aileen F.

The polycyclic aromatic hydrocarbon 7, 12-dimethylbenz[a]anthracene, (DMBA), targets and destroys all follicle types in rat and mouse ovaries. DMBA requires bioactivation to DMBA-3,4-diol-1,2-epoxide for ovotoxicity via formation of the intermediate, DMBA-3,4-diol (catalyzed by microsomal epoxide hydrolase; mEH). mEH was shown to be involved in DMBA bioactivation for ovotoxicity induction in B6C3F{sub 1} mouse ovaries. The current study compared DMBA and DMBA-3,4-diol mediated ovotoxicity, and investigated mEH involvement in DMBA-3,4-diol bioactivation in Fischer 344 (F344) rat ovary. F344 postnatal day (PND) 4 rat ovaries were cultured in vehicle control or media containing 1) DMBA or DMBA-3,4-diol (12.5 nM - 1 {mu}M;more » 15 days); 2) DMBA (1 {mu}M; 6 h - 15 days); and 3) DMBA (1 {mu}M) or DMBA-3,4-diol (75 nM) {+-} the mEH activity inhibitor cyclohexene oxide (CHO; 2 mM; 4 days). Ovaries were histologically evaluated and mEH mRNA and protein were measured by reverse transcriptase PCR or Western blotting, respectively. Ovotoxicity following 15 days of culture occurred (P < 0.05) at lower concentrations of DMBA-3,4-diol (12.5 nM - primordial; 75 nM - primary) than DMBA (75 nM - primordial; 375 nM - primary). The temporal pattern of mEH expression following DMBA exposure showed mRNA up-regulation (P < 0.05) on day 2, with increased protein (P < 0.05) on day 4, the earliest time of observed follicle loss (P < 0.05). mEH inhibition prevented DMBA-induced, but not DMBA-3,4-diol-induced ovotoxicity. These results demonstrate a conserved response in mice and rats for ovarian mEH involvement in DMBA bioactivation to its ovotoxic, 3,4-diol-1,2-epoxide form.« less

Broadband mid-infrared superlattice light-emitting diodes

NASA Astrophysics Data System (ADS)

Ricker, R. J.; Provence, S. R.; Norton, D. T.; Boggess, T. F.; Prineas, J. P.

2017-05-01

InAs/GaSb type-II superlattice light-emitting diodes were fabricated to form a device that provides emission over the entire 3-5 μm mid-infrared transmission window. Variable bandgap emission regions were coupled together using tunnel junctions to emit at peak wavelengths of 3.3 μm, 3.5 μm, 3.7 μm, 3.9 μm, 4.1 μm, 4.4 μm, 4.7 μm, and 5.0 μm. Cascading the structure recycles the electrons in each emission region to emit several wavelengths simultaneously. At high current densities, the light-emitting diode spectra broadened into a continuous, broadband spectrum that covered the entire mid-infrared band. When cooled to 77 K, radiances of over 1 W/cm2 sr were achieved, demonstrating apparent temperatures above 1000 K over the 3-5 μm band. InAs/GaSb type-II superlattices are capable of emitting from 3 μm to 30 μm, and the device design can be expanded to include longer emission wavelengths.

Comparison of Biological Properties of 99mTc-Labeled Cyclic RGD Peptide Trimer and Dimer Useful as SPECT Radiotracers for Tumor Imaging

PubMed Central

Zhao, Zuo-Quan; Yang, Yong; Fang, Wei; Liu, Shuang

2016-01-01

Introduction This study sought to evaluate a 99mTc-labeled trimeric cyclic RGD peptide (99mTc-4P-RGD3) as the new radiotracer for tumor imaging. The objective was to compare its biological properties with those of 99mTc-3P-RGD2 in the same animal model. Methods HYNIC-4P-RGD3 was prepared by reacting 4P-RGD3 with excess HYNIC-OSu in the presence of diisopropylethylamine. 99mTc-4P-RGD3 was prepared using a kit formulation, and evaluated for its tumor-targeting capability and biodistribution properties in the BALB/c nude mice with U87MG human glioma xenografts. Planar and SPECT imaging studies were performed in athymic nude mice with U87MG glioma xenografts. For comparison purpose, 99mTc-3P-RGD2 (a αvβ3-targeted radiotracer currently under clinical evaluation for tumor imaging in cancer patients) was also evaluated in the same animal models. Blocking experiments were used to demonstrate the αvβ3 specificity of 99mTc-4P-RGD3. Results 99mTc-4P-RGD3 was prepared with >95% RCP and high specific activity (~200 GBq/µmol). 99mTc-4P-RGD3 and 99mTc-3P-RGD2 shared almost identical tumor uptake and similar biodistribution properties. 99mTc-4P-RGD3 had higher uptake than 99mTc-3P-RGD2 in the intestines and kidneys; but it showed better metabolic stability. The U87MG tumors were clearly visualized by SPECT with excellent contrast with 99mTc-4P-RGD3 and 99mTc-3P-RGD2. Conclusion Increasing peptide multiplicity from 3P-RGD2 to 4P-RGD3 offers no advantages with respect to the tumor-targeting capability. 99mTc-4P-RGD3 is as good a SPECT radiotracer as 99mTc-3P-RGD2 for imaging αvβ3-positive tumors. PMID:27556955

Inventory of File sref.t03z.pgrb197.spread_ds_3hrly.grib2

Science.gov Websites

3 hour fcst U-Component of Wind [m/s] std dev 002 10 m above ground VGRD 3 hour fcst V-Component of Wind [m/s] std dev 003 2 m above ground TMP 3 hour fcst Temperature [K] std dev 004 2 m above ground SPFH 3 hour fcst Specific Humidity [kg/kg] std dev 005 10 m above ground WIND 3 hour fcst Wind Speed [m

Total fume and metal concentrations during welding in selected factories in Jeddah, Saudi Arabia.

PubMed

Balkhyour, Mansour Ahmed; Goknil, Mohammad Khalid

2010-07-01

Welding is a major industrial process used for joining metals. Occupational exposure to welding fumes is a serious occupational health problem all over the world. The degree of risk to welder's health from fumes depends on composition, concentration, and the length of exposure. The aim of this study was to investigate workers' welding fume exposure levels in some industries in Jeddah, Saudi Arabia. In each factory, the air in the breathing zone within 0.5 m from welders was sampled during 8-hour shifts. Total particulates, manganese, copper, and molybdenum concentrations of welding fumes were determined. Mean values of eight-hour average particulate concentrations measured during welding at the welders breathing zone were 6.3 mg/m(3) (Factory 1), 5.3 mg/m(3) (Factory 2), 11.3 mg/m(3) (Factory 3), 6.8 mg/m(3) (Factory 4), 4.7 mg/m(3) (Factory 5), and 3.0 mg/m(3) (Factory 6). Mean values of airborne manganese, copper, and molybdenum levels measured during welding were in the range of 0.010 mg/m(3)-0.477 mg/m(3), 0.001 mg/m(3)-0.080 mg/m(3) and 0.001 mg/m(3)-0.058 mg/m(3) respectively. Mean values of calculated equivalent exposure values were: 1.50 (Factory 1), 1.56 (Factory 2), 5.14 (Factory 3), 2.21 (Factory 4), 2.89 (Factory 5), and 1.20 (Factory 6). The welders in factories 1, 2, 3, and 4 were exposed to welding fume concentration above the SASO limit value, which may increase the risk of respiratory health problems.

Impact of Na- and K-C pi-interactions on the structure and binding of M3(sol)n(BINOLate)3Ln catalysts.

PubMed

Wooten, Alfred J; Carroll, Patrick J; Walsh, Patrick J

2007-08-16

Shibasaki's heterobimetallic complexes M3(THF)n(BINOLate)3Ln [M = Li, Na, K; Ln = lanthanide(III)] are among the most successful asymmetric Lewis acid catalysts. Why does M3(THF)n(BINOLate)3Ln readily bind substrates when M = Li but not when M = Na or K? Structural studies herein indicate Na- and K-C cation-pi interactions and alkali metal radius may be more important than even lanthanide radius. Also reported is a novel polymeric [K3(THF)2(BINOLate)3Yb]n structure that provides the first evidence of interactions between M3(THF)n(BINOLate)3Ln complexes.

Impact of Na- and K-C π-Interactions on the Structure and Binding of M3(sol)n(BINOLate)3Ln Catalysts

PubMed Central

Wooten, Alfred J.; Carroll, Patrick J.; Walsh, Patrick J.

2008-01-01

Shibasaki’s heterobimetallic complexes M3(THF)n(BINOLate)3Ln [M = Li, Na, K, Ln = lanthanide(III)] are among the most successful asymmetric Lewis acid catalysts. Why does M3(THF)n(BINOLate)3Ln readily bind substrates when M = Li but not when M = Na or K? Structural studies herein indicate Na- and K-C cation-π interactions and alkali metal radius may be more important than even lanthanide radius. Also reported is a novel polymeric [K3(THF)2(BINOLate)3Yb]n structure that provides the first evidence of interactions between M3(THF)n(BINOLate)3Ln complexes. PMID:17658838

[Incidence and distribution of Streptococcus pyogenes type M in patients treated at the Dr. Fran Mihaljević Infectious Disease Clinic in Zagreb from 1990 to 1996].

PubMed

Bejuk, Danijela; Begovac, Josip

2002-01-01

The aim of this study was to estimate the changes in the appearance and distribution of M types of Streptococcus pyogenes in different cultures from 78 patients treated during the 1990-1996 period at the Dr. Fran Mihaljević University Hospital for Infectious Diseases in Zagreb. Isolates were characterized by the T-agglutination pattern and M type and/or opacity factor type using the standards recommended by two World Health Organization Collaborating Centers for Reference and Research on streptococci from Minneapolis and Prague. In this study, 19% (15/79) of isolates were recovered from normally sterile sites, 26.6% (21/79) came from skin and 54.4% (43/79) from throat swabs. In one patient isolates from the skin and blood culture were analyzed. Of all, 92.4% (73/79) of the isolates were typed by T-agglutination pattern and 73.5% (58/79) by M protein and/or OF typing. The results of M typing showed 14 M types: M1, M3, M4, M5, M6, M11, M12, M28, M57, M58, M60, M75, M76 and M78. The most commonly isolated types were M1 and M3 (13.8%, 8/58 each), followed by M28 found in 12.1% (7/58), and M6 and M12 in 10.3% (6/58) each. These five M types accounted for 60.3% (35/58) of all isolates. Analysis to changes in the distribution of M1 and M3 types during the 1990-1991 and 1992-1993 periods revealed a significantly greater proportion of M1 and M3 isolates in the former (Fisher's two-tailed exact test, p = 0.018). A significantly greater proportion of M1 and M3 isolates was also recorded in the 1990-1991, than in 1994-1996 period. (Fisher's two-tailed exact test, P = 0.021). It was investigated whether Streptococcus pyogenes M1 and M3 types were associated with toxic and invasive infection. There were 28.2% (22/78) of patients with toxic and invasive infection: 31.9% (7/22) of them with the diagnosis of scarlet fever, whereas 68.1% (15/22) of the strains were obtained from normally sterile sites. There were 45.5% (10/22) of M1 and M3 types from patients with toxic and invasive infections. Types M6, M28 and M76 were found in an equal proportion of 9.1% (2/22), and M4, M12 and M 60 of 4.5% (1/22) each. In three strains, M type could not be identified (T8/25 SOR+, T25 SOR+ and T11 SOR+). M1 and M3 types were isolated from 10.3% (6/56) of patients with other streptococcal infections. A significantly greater proportion of M1 and M3 types was recorded in patients with toxic and invasive infections than in those with other streptococcal infections (Fisher's two-tailed exact test, p = 0.004). A multivariate logistic regression model was used to assess whether the increased proportion of streptococcal M types 1 and 3 was associated with the 1990-1991 period, or with the infection characteristics. The changes in the distribution of M types 1 and 3 were found to be significantly associated only with toxic and invasive infections (odds ratio 4.35, p = 0.025). Odds ratio suggests that patients with toxic and invasive infections had a 4.35--fold increased risk of infections caused by types M1 and M3 found in patients with other streptococcal infections. The increased proportion of M types 1 and 3 during the 1990-1991 period was more significantly associated with the characteristics of infection than with the study period.

40 CFR 1065.720 - Liquefied petroleum gas.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., C3H8 Minimum, 0.85 m3/m3 ASTM D2163-05. Vapor pressure at 38 °C Maximum, 1400 kPa ASTM D1267-02 or 2598-022. Volatility residue (evaporated temperature, 35 °C) Maximum, −38 °C ASTM D1837-02a. Butanes Maximum, 0.05 m3/m3 ASTM D2163-05. Butenes Maximum, 0.02 m3/m3 ASTM D2163-05. Pentenes and heavier Maximum...

Metabolic roles of the M3 muscarinic acetylcholine receptor studied with M3 receptor mutant mice: a review.

PubMed

Gautam, Dinesh; Jeon, Jongrye; Li, Jian Hua; Han, Sung-Jun; Hamdan, Fadi F; Cui, Yinghong; Lu, Huiyan; Deng, Chuxia; Gavrilova, Oksana; Wess, Jürgen

2008-01-01

The M(3) muscarinic acetylcholine (ACh) receptor (M(3) mAChR) is expressed in many central and peripheral tissues. It is a prototypic member of the superfamily of G protein-coupled receptors and preferentially activates G proteins of the G(q) family. Recent studies involving the use of newly generated mAChR mutant mice have revealed that the M(3) mAChR plays a key role in regulating many important metabolic functions. Phenotypic analyses of mutant mice that either selectively lacked or overexpressed M(3) receptors in pancreatic beta -cells indicated that beta -cell M(3) mAChRs are essential for maintaining proper insulin release and glucose homeostasis. The experimental data also suggested that strategies aimed at enhancing signaling through beta -cell M(3) mAChRs might be beneficial for the treatment of type 2 diabetes. Recent studies with whole body M(3) mAChR knockout mice showed that the absence of M(3) receptors protected mice against various forms of experimentally or genetically induced obesity and obesity-associated metabolic deficits. Under all experimental conditions tested, M(3) receptor-deficient mice showed greatly ameliorated impairments in glucose homeostasis and insulin sensitivity, reduced food intake, and a significant elevation in basal and total energy expenditure, most likely due to increased central sympathetic outflow and increased rate of fatty acid oxidation. These findings are of potential interest for the development of novel therapeutic approaches for the treatment of obesity and associated metabolic disorders.

Variability of total exposure to PM2.5 related to indoor and outdoor pollution sources Krakow study in pregnant women.

PubMed

Jedrychowski, Wieslaw A; Perera, Frederica P; Pac, Agnieszka; Jacek, Ryszard; Whyatt, Robin M; Spengler, John D; Dumyahn, Thomas S; Sochacka-Tatara, Elzbieta

2006-07-31

The study is a part of an ongoing prospective cohort study on the relationship between the exposure to environmental factors during pregnancy and birth outcomes and health of newborns. We have measured personal PM(2.5) level in the group of 407 non-smoking pregnant women during the 2nd trimester of pregnancy. On average, the participants from the city center were exposed to higher exposure than those from the outer city area (GM=42.0 microg/m(3), 95% CI: 36.8-48.0 vs. 35.8 microg/m(3), 95% CI: 33.5-38.2 microg/m(3)). More than 20% of study subjects were affected by high level of PM(2.5) pollution (above 65 microg/m(3)). PM(2.5) concentrations were higher during the heating season (GM=43.4 microg/m(3), 95% CI: 40.1-46.9 microg/m(3)) compared to non-heating season (GM=29.8 microg/m(3), 95% CI: 27.5-32.2 microg/m(3)). Out of all potential outdoor air pollution sources (high traffic density, bus depot, waste incinerator, industry etc.) considered in the bivariate analysis, only the proximity of industrial plant showed significant impact on the personal exposure (GM=54.3 microg/m(3), 95% CI: 39.4-74.8 microg/m(3)) compared with corresponding figure for those who did not declare living near the industrial premises (GM=36.2 microg/m(3), 95% CI: 34.1-38.4 microg/m(3)). The subjects declaring high exposure to ETS (>10 cigarettes daily) have shown very high level of personal exposure (GM=88.8 microg/m(3), 95% CI: 73.9-106.7 microg/m(3)) compared with lower ETS exposure (< or =10 cigarettes) (GM=46.3 microg/m(3), 95% CI: 40.0-53.5 microg/m(3)) and no-ETS exposure group (GM=33.9 microg/m(3), 95% CI: 31.8-36.1 microg/m(3)). The contribution of the background ambient PM(10) level was very strong determinant of the total personal exposure to PM(2.5) and it explained about 31% of variance between the subjects followed by environmental tobacco smoke (10%), home heating by coal/wood stoves (2%), other types of heating (2%) and the industrial plant localization in the proximity of household (1%).

Effect of Dry Needling on Thigh Muscle Strength and Hip Flexion in Elite Soccer Players.

PubMed

Haser, Christian; Stöggl, Thomas; Kriner, Monika; Mikoleit, Jörg; Wolfahrt, Bernd; Scherr, Johannes; Halle, Martin; Pfab, Florian

2017-02-01

Increase in muscle force, endurance, and flexibility is desired in elite athletes to improve performance and to avoid injuries, but it is often hindered by the occurrence of myofascial trigger points. Dry needling (DN) has been shown effective in eliminating myofascial trigger points. This randomized controlled study in 30 elite youth soccer players of a professional soccer Bundesliga Club investigated the effects of four weekly sessions of DN plus water pressure massage on thigh muscle force and range of motion of hip flexion. A group receiving placebo laser plus water pressure massage and a group with no intervention served as controls. Data were collected at baseline (M1), treatment end (M2), and 4 wk follow-up (M3). Furthermore, a 5-month muscle injury follow-up was performed. DN showed significant improvement of muscular endurance of knee extensors at M2 (P = 0.039) and M3 (P = 0.008) compared with M1 (M1:294.6 ± 15.4 N·m·s, M2:311 ± 25 N·m·s; M3:316.0 ± 28.6 N·m·s) and knee flexors at M2 compared with M1 (M1:163.5 ± 10.9 N·m·s, M2:188.5 ± 16.3 N·m·s) as well as hip flexion (M1: 81.5° ± 3.3°, M2:89.8° ± 2.8°; M3:91.8° ± 3.8°). Compared with placebo (3.8° ± 3.8°) and control (1.4° ± 2.9°), DN (10.3° ± 3.5°) showed a significant (P = 0.01 and P = 0.0002) effect at M3 compared with M1 on hip flexion; compared with nontreatment control (-10 ± 11.9 N·m), DN (5.2 ± 10.2 N·m) also significantly (P = 0.049) improved maximum force of knee extensors at M3 compared with M1. During the rest of the season, muscle injuries were less frequent in the DN group compared with the control group. DN showed a significant effect on muscular endurance and hip flexion range of motion that persisted 4 wk posttreatment. Compared with placebo, it showed a significant effect on hip flexion that persisted 4 wk posttreatment, and compared with nonintervention control, it showed a significant effect on maximum force of knee extensors 4 wk posttreatment in elite soccer players.

Budget impact analysis of insulin therapies and associated delivery systems.

PubMed

Lee, Lauren J; Smolen, Lee J; Klein, Timothy M; Foster, Shonda A; Whiteman, Doug; Jorgenson, James A; Hultgren, Steve

2012-06-01

A budget impact analysis of insulin therapies and associated delivery systems is presented. Based on inputted procurement totals, per-item costs (based on 2011 average wholesale price), insulin distribution system (floor stock or individual patient supply), waste, and treatment protocols for a specified time frame, the budget impact model approximated the number of patients treated with subcutaneous insulin, costs, utilization, waste, and injection mechanism (pen safety needle or syringe) costs. To calculate net changes, results of one-year 3-mL vial use were subtracted from one-year 10-mL vial or 3-mL pen use. Switching from a 10-mL vial to a 3-mL vial was associated with reductions in both costs and waste. The net reductions in costs and waste ranged from $15,482 and 120,000 IU, respectively, for floor-stock 10-mL vial to floor-stock 3-mL vial conversion to $871,548 and 6,750,000 IU, respectively, for individual patient supply 10-mL vial to floor-stock 3-mL vial conversion. Switching from floor-stock 10-mL vials to individual patient supply 3-mL vials increased costs and waste by $164,659 and 1,275,000 IU, respectively. Converting from individual patient supply 3-mL pens to individual patient supply 3-mL vials reduced costs by $117,236 but did not decrease waste. A budget impact analysis of the conversion of either 10-mL insulin vials or 3-mL insulin pens to 3-mL insulin vials found reductions in both cost and waste, except when converting from floor-stock 10-mL vials to individual patient supply 3-mL vials.

Differential in vitro inhibition of M3G and M6G formation from morphine by (R)- and (S)-methadone and structurally related opioids

PubMed Central

Morrish, Glynn A; Foster, David J R; Somogyi, Andrew A

2006-01-01

Aims To determine the in vitro kinetics of morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) formation and the inhibition potential by methadone enantiomers and structurally related opioids. Methods M3G and M6G formation kinetics from morphine were determined using microsomes from five human livers. Inhibition of glucuronide formation was investigated with eight inhibitors (100 µm) and the mechanism of inhibition determined for (R)- and (S)-methadone (70–500 µm) using three microsomal samples. Results Glucuronide formation displayed single enzyme kinetics. The M3G Vmax (mean ± SD) was 4.8-fold greater than M6G Vmax (555 ± 110 vs. 115 ± 19 nmol mg−1 protein h−1; P = 0.006, mean of difference 439; 95% confidence interval 313, 565 nmol mg−1 protein h−1). Km values for M3G and M6G formation were not significantly different (1.12 ± 0.37 vs. 1.11 ± 0.31 mm; P = 0.89, 0.02; −0.29, 0.32 mm). M3G and M6G formation was inhibited (P < 0.01) with a significant increase in the M3G/M6G ratio (P < 0.01) for all compounds tested. Detailed analysis with (R)- and (S)-methadone revealed noncompetitive inhibition with (R)-methadone Ki of 320 ± 42 µm and 192 ± 12 µm for M3G and M6G, respectively, and (S)-methadone Ki of 226 ± 30 µm and 152 ± 20 µm for M3G and M6G, respectively. Ki values for M3G inhibition were significantly greater than for M6G for (R)-methadone (P = 0.017, 128; 55, 202 µm) and (S)-methadone (P = 0.026, 75; 22, 128 µm). Conclusions Both methadone enantiomers noncompetitively inhibited the formation of morphine's primary metabolites, with greater inhibition of M6G formation compared with M3G. These findings indicate a mechanism for reduced morphine clearance in methadone-maintained patients and reduced relative formation of the opioid active M6G compared with M3G. PMID:16487227

mTORC1 activity repression by late endosomal phosphatidylinositol 3,4-bisphosphate.

PubMed

Marat, Andrea L; Wallroth, Alexander; Lo, Wen-Ting; Müller, Rainer; Norata, Giuseppe Danilo; Falasca, Marco; Schultz, Carsten; Haucke, Volker

2017-06-02

Nutrient sensing by mechanistic target of rapamycin complex 1 (mTORC1) on lysosomes and late endosomes (LyLEs) regulates cell growth. Many factors stimulate mTORC1 activity, including the production of phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P 3 ] by class I phosphatidylinositol 3-kinases (PI3Ks) at the plasma membrane. We investigated mechanisms that repress mTORC1 under conditions of growth factor deprivation. We identified phosphatidylinositol 3,4-bisphosphate [PI(3,4)P 2 ], synthesized by class II PI3K β (PI3KC2β) at LyLEs, as a negative regulator of mTORC1, whereas loss of PI3KC2β hyperactivated mTORC1. Growth factor deprivation induced the association of PI3KC2β with the Raptor subunit of mTORC1. Local PI(3,4)P 2 synthesis triggered repression of mTORC1 activity through association of Raptor with inhibitory 14-3-3 proteins. These results unravel an unexpected function for local PI(3,4)P 2 production in shutting off mTORC1. Copyright © 2017, American Association for the Advancement of Science.

Synergistic effects of fenbendazole and metronidazole against Giardia muris in Swiss mice naturally infected.

PubMed

Bezagio, Renata Coltro; Colli, Cristiane Maria; Romera, Liara Izabela Lopes; Ferreira, Érika Cristina; Falavigna-Guilherme, Ana Lúcia; Gomes, Mônica Lúcia

2017-03-01

In this study were proposed different protocols for the treatment of mice naturally infected with Giardia muris. Male Swiss mice were divided into seven groups, with five animals each, in a blind, controlled, randomized by drawing lots and once-repeated experiment. Parasite detection and cure control were performed using the Faust method and search by trophozoites in the intestinal mucosa. Clinical parameters (weight, water and feed consumption, elimination of excreta, aspect of the fur and feces) were also evaluated. All animals were treated with metronidazole (M), fenbendazole (F), and probiotics (P), administered intragastrically, during 7 days. M1, FM1, and F1 groups were treated 1×/day; M3, FM3, and PM3 groups 3×/day; and ST (control group) received only water. After the 5th and 7th days of treatment, the animals in FM1/FM3 and PM3/M3 groups presented, respectively, negative results and remained negative in the following 10 days. Animals in F1 group consumed less water (p = 0.00010) compared with FM1/FM3/PM3. The animals in M1 group compared with FM3/M3, F1 compared with M3, and ST compared with FM1/FM3/M3/PM3 consumed a larger amount of feed (p = 0.00001). The animals in F1 group compared with FM3/M1/M3/PM3, FM1 compared with FM3, and ST compared with FM3/M1/M3/PM3 eliminated lower volume of excreta (p = 0.00001). The results show that the association between F and M potentiates the effects, indicating a synergistic action of these two drugs, and FM1 is the best protocol due to early negativity in the animals, lower concentrations of the drugs, lower risk of toxicity and stress, and less alterations in clinical parameters.

Pilot-scale gasification of woody biomass

Treesearch

Thomas Elder; Leslie H. Groom

2011-01-01

The gasification of pine and mixed-hardwood chips has been carried out in a pilot-scale system at a range of gas flow rates. Consuming ~17-30 kgh-1 of feedstock, the producer gas was composed of ~200 dm3 m-3 carbon monoxide, 12 dm3 m-3 carbon dioxide, 30 dm3 m-3 methane and 190 dm3 m-3 hydrogen, with an energy content of ~6 MJ m-3 for both feedstocks. It was found that...

Diel variations of the bathymetric distribution of zooplankton groups and biomass in Cap-Ferret Canyon, France

NASA Astrophysics Data System (ADS)

Maycas, Encarna Ribera; Bourdillon, André; Macquart-Moulin, Claude; Passelaigue, Françoise; Patriti, Gilbert

1999-10-01

The bathymetric distribution, abundance and diel vertical migrations (DVM) of zooplankton were investigated along the axis of the Cap-Ferret Canyon (Bay of Biscay, French Atlantic coast) by a consecutive series of synchronous net hauls that sampled the whole water column (0-2000 m in depth) during a diel cycle. The distribution of appendicularians (maximum 189 individuals m -3), cladocerans (maximum 287 individuals m -3), copepods (copepods<4 mm, maximum 773 individuals m -3, copepods>4 mm, maximum 13 individuals m -3), ostracods (maximum 8 individuals m -3), siphonophores (maximum >2 individuals m -3) and peracarids (maximum >600 individuals 1000 m -3) were analysed and represented by isoline diagrams. The biomass of total zooplankton (maximum 18419 μg C m -3, 3780 μg N m -3) and large copepods (>4 mm maximum 2256 μg C m -3, 425 μg N m -3) also were determined. Vertical migration was absent or affected only the epipelagic zone for appendicularians, cladocerans, small copepods and siphonophores. Average amplitude of vertical migration was about 400-500 m for ostracods, some hyperiids and mysids, and large copepods, which were often present in the epipelagic, mesopelagic, and bathypelagic zones. Large copepods can constitute more than 80% of the biomass corresponding to total zooplankton. They may play an important role in the active vertical transfer of carbon and nitrogen.

[Anti-M3 muscarinic acetylcholine receptor antibodies and Sjögren's syndrome].

PubMed

Tsuboi, Hiroto; Iizuka, Mana; Asashima, Hiromitsu; Sumida, Takayuki

2013-01-01

Sjögren's syndrome (SS) is an autoimmune disease that affects exocrine glands including salivary and lacrimal glands. It is characterized by lymphocytic infiltration into exocrine glands, leading to dry mouth and eyes. A number of auto-antibodies are detected in patients with SS. However, no SS-specific pathologic auto-antibodies have yet been found in this condition. M3 muscarinic acetylcholine receptor (M3R) plays a crucial role in the secretion of saliva. It is reported that some patients with SS carried inhibitory auto-antibodies against M3R. To clarify the epitopes and function of anti-M3R antibodies in SS, we examined antibodies to the extracellular domains (N terminal region, the first, second, and third extracellular loop) of M3R by ELISA using synthesized peptide antigens encoding these domains in 42 SS and 42 healthy controls (HC). Titers and positivity of anti-M3R antibodies to every extracellular domain of M3R were significantly higher in SS than in HC. Our results indicated the presence of several B cell epitopes on M3R in SS. Moreover, we analyzed the functions of anti-M3R antibodies by Ca(2+)-influx assays using a human salivary gland (HSG) cell line. The functional analysis indicated that the influence of such anti-M3R antibodies on Ca(2+)-influx in HSG cells might differ based on the epitopes to which they bind. Interestingly, both IgG from anti-M3R antibodies to the second extracellular loop positive SS and anti-M3R monoclonal antibodies against the second extracellular loop of M3R, which we generated, suppressed Ca(2+)-influx in the HSG cells induced by cevimeline stimulation. These observations suggested that auto-antibodies against the second extracellular loop of M3R could be involved in salivary dysfunction in patients with SS. These results indicated the presence of several B cell epitopes on M3R in SS and the influence of anti-M3R antibodies on salivary secretion might differ based on these epitopes. Thus, anti-M3R antibodies could be not only potential pathologic auto-antibodies, but also new diagnostic makers and therapeutic targets for SS.

Methylation of arsenic by recombinant human wild-type arsenic (+ 3 oxidation state) methyltransferase and its methionine 287 threonine (M287T) polymorph: Role of glutathione

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Lan; Saunders, R. Jesse; Drobná, Zuzana

2012-10-01

Arsenic (+ 3 oxidation state) methyltransferase (AS3MT) is the key enzyme in the pathway for methylation of arsenicals. A common polymorphism in the AS3MT gene that replaces a threonyl residue in position 287 with a methionyl residue (AS3MT/M287T) occurs at a frequency of about 10% among populations worldwide. Here, we compared catalytic properties of recombinant human wild-type (wt) AS3MT and AS3MT/M287T in reaction mixtures containing S-adenosylmethionine, arsenite (iAs{sup III}) or methylarsonous acid (MAs{sup III}) as substrates and endogenous or synthetic reductants, including glutathione (GSH), a thioredoxin reductase (TR)/thioredoxin (Trx)/NADPH reducing system, or tris (2-carboxyethyl) phosphine hydrochloride (TCEP). With either TR/Trx/NADPHmore » or TCEP, wtAS3MT or AS3MT/M287T catalyzed conversion of iAs{sup III} to MAs{sup III}, methylarsonic acid (MAs{sup V}), dimethylarsinous acid (DMAs{sup III}), and dimethylarsinic acid (DMAs{sup V}); MAs{sup III} was converted to DMAs{sup III} and DMAs{sup V}. Although neither enzyme required GSH to support methylation of iAs{sup III} or MAs{sup III}, addition of 1 mM GSH decreased K{sub m} and increased V{sub max} estimates for either substrate in reaction mixtures containing TR/Trx/NADPH. Without GSH, V{sub max} and K{sub m} values were significantly lower for AS3MT/M287T than for wtAS3MT. In the presence of 1 mM GSH, significantly more DMAs{sup III} was produced from iAs{sup III} in reactions catalyzed by the M287T variant than in wtAS3MT-catalyzed reactions. Thus, 1 mM GSH modulates AS3MT activity, increasing both methylation rates and yield of DMAs{sup III}. AS3MT genotype exemplified by differences in regulation of wtAS3MT and AS3MT/M287T-catalyzed reactions by GSH may contribute to differences in the phenotype for arsenic methylation and, ultimately, to differences in the disease susceptibility in individuals chronically exposed to inorganic arsenic. -- Highlights: ► Human AS3MT and AS3MT(M287T) require a dithiol reductant for optimal activity. ► Both enzymes methylate arsenite to tri- and pentavalent methylated metabolites. ► Neither enzyme requires glutathione (GSH) to methylate arsenite or methylarsonite. ► However, in presence of a dithiol addition of 1 mM GSH increases methylation rates. ► In presence of 1 mM GSH, AS3MT(M287T) produces more dimethylarsinite than AS3MT.« less

Tuneable reactivity with PPh3 and SnX2 of four- and five-coordinate Pd(II) and Pt(II) complexes containing polyphosphines.

PubMed

Fernández-Anca, Damián; García-Seijo, M Inés; García-Fernández, M Esther

2013-07-28

The reactivity of the unusual d(8) trigonal-bipyramidal systems [MX(PP3)]X (X = Cl: M = Pd(1a), Pt(2a); X = Br: M = Pd(3a), Pt(4a); X = I: M = Pd(5a), Pt(6a); PP3 = tris[2-(diphenylphosphino)ethyl]phosphine) in CHCl3-CH3OH, the square-pyramidal compounds [MCl(NP3)]Cl (M = Pd(7a); Pt(8a); NP3 = tris[2-(diphenylphosphino)ethyl]amine) in CD3OD-DMF and the distorted square-planar mononuclear [MX(PNP)]X (M = Pd: X = Cl(10a); M = Pt: X = I(10b); PNP = bis[2-(diphenylphosphino)ethyl]amine) and the heteronuclear [PdAu2X4(PP3)] [X = I(9a), Cl(14a), Br(15a)] and [MAuX2(PP3)]X [M = Pd: X = Cl(16a); M = Pt: X = Cl(17a), Br(18a)] species in CDCl3 with PPh3 + SnX2 has been explored to establish the factors that influence the nature of the products. With the mononuclear precursors the course of the reaction is strongly dependent on the tripodal or linear arrangement of the polydentate ligand and in the former case on the halogen. Thus, while for chlorides (1a-2a, 7a-8a) and bromides (3a-4a) the reaction led to the trigonal-bipyramidal compounds [M(SnCl3)(AP3)][SnCl3] [A = P: M = Pd(1), Pt(2); A = N: M = Pd(7), Pt(8)], [MBr(PP3)][SnBr3] [M = Pd(4), Pt(6)] containing M-Sn and M-Br bonds, respectively, for iodides (5a-6a) resulted in the unknown neutral square-planar compounds [MI2(PP(PO)2)(SnI2)2] [M = Pd(9) and Pt(10)] bearing two dangling P=O-SnI2 units and P2MI2 environments. However, complexes of the type [PtCl(PP2PO)X]X' [X = SnCl2, X' = [SnCl3](-)(11)] and [M(PP(PO)2)2X4]X'2 [X = SnCl2, X' = [SnCl3](-): M = Pd(12), Pt(13)] showing P=O-SnCl2 arms were obtained by direct reaction of [PtCl(PP2PO)]Cl (11a) and [M(PP(PO)2)2]Cl2 [M = Pd(12a), Pt(13a)] with SnCl2 in CH3OH. Although complex 9 was also prepared by interaction of the heteronuclear iodide 9a with PPh3 + SnI2 in CDCl3, the use of the neutral and ionic heteronuclear chlorides and bromides (14a-18a) as starting materials afforded the distorted square-planar ionic systems [MAuX'(PP3)(PPh3)][SnX3]2 [M = Pd: X = Cl, X' = SnCl3(-)(14); X = Br, X' = SnBr3(-)(15); M = Pt: X = Cl, X' = SnCl3(-)(17); X = Br, X' = SnBr3(-)(18)] containing M-SnX3 and P-Au-PPh3 functionalities. It was found that these reactions where the heteronuclear species are the precursors proceed via the trigonal-bipyramidal halides not only with X = Cl and Br(1a-4a) but also I(5a). When the precursors were 10a and 10b the reaction occurred with formation of [Pd(PNP)(PPh3)][SnCl3]2 (23) and [Pt(PNP)(PPh3)][SnCl2I]2 (24) showing M-PPh3 units and trihalostannato counter anions.

Effect of Asymptomatic Visible Third Molars on Periodontal Health of Adjacent Second Molars: A Cross-Sectional Study.

PubMed

Qu, Hong-Lei; Tian, Bei-Min; Li, Kun; Zhou, Li-Na; Li, Zhi-Bang; Chen, Fa-Ming

2017-10-01

Evidence that asymptomatic third molars (M3s) negatively affect their adjacent second molars (A-M2s) is limited. The present study evaluated the association between visible M3s (V-M3s) of various clinical status with the periodontal pathologic features of their A-M2s. Subjects with at least 1 quadrant having intact first and second molars, either with V-M3s and symptom free or without adjacent V-M3s, were enrolled in the present cross-sectional investigation. Periodontal parameters, including plaque index (PLI), bleeding on probing (BOP), probing pocket depth (PPD), and at least 1 site with a PPD of 5 mm or more (PPD5+), obtained from M2s were analyzed according to the presence or absence of V-M3s or the status of the M3s. The χ 2 test or t test was used to compare the mean PLI, PPD, BOP percentage, and PPD5+ percentage. The association of PPD5+ with V-M3 status was assessed using a multivariable logistic regression model (quadrant-based analysis), and variances were adjusted for clustered observations within subjects. In total, 572 subjects were enrolled in the study, and 423 had at least 1 V-M3. At the in-quadrant level, the presence of a V-M3 significantly increased M2 pathologic parameters, including PLI, PPD, BOP, and PPD5+. When analyzed using a multivariate logistic regression model, impacted M3s and normally erupted M3s significantly elevated the risk of PPD5+ on their A-M2s (odds ratio 3.20 and 1.67, respectively). Other factors associated with an increased odds of PPD5+ were mandibular region and older age. Finally, the patient-matched comparison showed that the percentage of BOP and PPD5+ on M2s increased when V-M3s were present. Irrespective of their status, the presence of V-M3s is a risk factor for the development of periodontal pathologic features in their A-M2s. Although the prophylactic removal of asymptomatic V-M3s remains controversial, medical decisions should be made as early as possible, because, ideally, extraction should be performed before symptom onset. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Cyclic fatigue resistance, torsional resistance, and metallurgical characteristics of M3 Rotary and M3 Pro Gold NiTi files

PubMed Central

2018-01-01

Objectives To evaluate the mechanical properties and metallurgical characteristics of the M3 Rotary and M3 Pro Gold files (United Dental). Materials and Methods One hundred and sixty new M3 Rotary and M3 Pro Gold files (sizes 20/0.04 and 25/0.04) were used. Torque and angle of rotation at failure (n = 20) were measured according to ISO 3630-1. Cyclic fatigue resistance was tested by measuring the number of cycles to failure in an artificial stainless steel canal (60° angle of curvature and a 5-mm radius). The metallurgical characteristics were investigated by differential scanning calorimetry. Data were analyzed using analysis of variance and the Student-Newman-Keuls test. Results Comparing the same size of the 2 different instruments, cyclic fatigue resistance was significantly higher in the M3 Pro Gold files than in the M3 Rotary files (p < 0.001). No significant difference was observed between the files in the maximum torque load, while a significantly higher angular rotation to fracture was observed for M3 Pro Gold (p < 0.05). In the DSC analysis, the M3 Pro Gold files showed one prominent peak on the heating curve and 2 prominent peaks on the cooling curve. In contrast, the M3 Rotary files showed 1 small peak on the heating curve and 1 small peak on the cooling curve. Conclusions The M3 Pro Gold files showed greater flexibility and angular rotation than the M3 Rotary files, without decrement of their torque resistance. The superior flexibility of M3 Pro Gold files can be attributed to their martensite phase. PMID:29765904

The PNPLA3 variant associated with fatty liver disease (I148M) accumulates on lipid droplets by evading ubiquitylation.

PubMed

BasuRay, Soumik; Smagris, Eriks; Cohen, Jonathan C; Hobbs, Helen H

2017-10-01

A sequence variation (I148M) in patatin-like phospholipase domain-containing protein 3 (PNPLA3) is strongly associated with fatty liver disease, but the underlying mechanism remains obscure. In this study, we used knock-in (KI) mice (Pnpla3 148M/M ) to examine the mechanism responsible for accumulation of triglyceride (TG) and PNPLA3 in hepatic lipid droplets (LDs). No differences were found between Pnpla3 148M/M and Pnpla3 +/+ mice in hepatic TG synthesis, utilization, or secretion. These results are consistent with TG accumulation in the Pnpla3 148M/M mice being caused by impaired TG mobilization from LDs. Sucrose feeding, which is required to elicit fatty liver in KI mice, led to a much larger and more persistent increase in PNPLA3 protein in the KI mice than in wild-type (WT) mice. Inhibition of the proteasome (bortezomib), but not macroautophagy (3-methyladenine), markedly increased PNPLA3 levels in WT mice, coincident with the appearance of ubiquitylated forms of the protein. Bortezomib did not increase PNPLA3 levels in Pnpla3 148M/M mice, and only trace amounts of ubiquitylated PNPLA3 were seen in these animals. These results are consistent with the notion that the 148M variant disrupts ubiquitylation and proteasomal degradation of PNPLA3, resulting in accumulation of PNPLA3-148M and impaired mobilization of TG from LDs. (Hepatology 2017;66:1111-1124). © 2017 The Authors. Hepatology published by Wiley Periodicals, Inc., on behalf of the American Association for the Study of Liver Diseases.

Differential changes in mGlu2 and mGlu3 gene expression following pilocarpine-induced status epilepticus: A comparative real-time PCR analysis

PubMed Central

Ermolinsky, Boris; Pacheco Otalora, Luis F.; Arshadmansab, Massoud F.; Zarei, Masoud; Garrido-Sanabria, Emilio R.

2008-01-01

Group II metabotropic glutamate (mGlu II) receptors subtype 2 and 3 (mGlu2 and mGlu3) are subtle regulators of neuronal excitability and synaptic plasticity in the hippocampus. In recent years, researchers have investigated the potential neuroprotective and anticonvulsant effects of compounds acting on mGlu II receptors. However, abnormal expression and function of mGlu2 and mGlu3 have been reported in temporal lobe epilepsy, a phenomena that may limit the therapeutic effectiveness of these potentially new antiepileptic drugs. Here, we investigated seizure-induced changes in mGlu2 and mGlu3 mRNA following pilocarpine-inducted status epilepticus (SE) and subsequent epileptogenesis. Relative changes in gene expression were assessed by comparative analysis of quantitative real-time PCR (qrtPCR) by the delta-delta CT method. Pilocarpine-treated and control rats were sacrificed at different periods (24h, 10 days, one month and more than two months) following SE. Total RNA was isolated from microdissected dentate gyrus and processed for RT-PCR and qrtPCR using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as an endogenous control gene. Analysis of relative quantification (RQ) ratios of mGlu2 and mGlu3 mRNA expression revealed a significant down-regulation of both targets at 24h after SE. Gene expression partially recovered at 10 days following SE reaching control levels at one month after SE. Two month after SE, mGlu2 mRNA expression was significantly down-regulated to ~41% of control expression whereas mGlu3 mRNA was comparable to control levels. Our data indicate that mGlu2 and mGlu3 expression is dynamically down-regulated or selectively enhanced during critical periods of epileptogenesis. Seizure-induced differential dysregulation of mGlu2 and mGlu3 receptors may affect the availability of these molecular targets for therapeutic compounds in epilepsy. PMID:18585369

Photoelectron spectroscopy and theoretical study of M(IO3)2(-) (M = H, Li, Na, K): structural evolution, optical isomers, and hyperhalogen behavior.

PubMed

Hou, Gao-Lei; Wu, Miao Miao; Wen, Hui; Sun, Qiang; Wang, Xue-Bin; Zheng, Wei-Jun

2013-07-28

H(IO3)2(-) and M(IO3)2(-) (M = Li, Na, K) anions were successfully produced via electrospray ionization of their corresponding bulk salt solutions, and were characterized by combining negative ion photoelectron spectroscopy and quantum chemical calculations. The experimental vertical detachment energies (VDEs) of M(IO3)2(-) (M = H, Li, Na, K) are 6.25, 6.57, 6.60, and 6.51 eV, respectively, and they are much higher than that of IO3(-) (4.77 eV). The theoretical calculations show that each of these anions has two energetically degenerate optical isomers. It is found that the structure of H(IO3)2(-) can be written as IO3(-)(HIO3), in which the H atom is tightly bound to one of the IO3(-) groups and forms an iodic acid (HIO3) molecule; while the structures of M(IO3)2(-) can be written as (IO3(-))M(+)(IO3(-)), in which the alkali metal atoms interact with the two IO3(-) groups almost equally and bridge the two IO3(-) groups via two O atoms of each IO3(-) with the two MOOI planes nearly perpendicular to each other. In addition, the high VDEs of M(IO3)2(-) (M = Li, Na, K) can be explained by the hyperhalogen behavior of their neutral counterparts.

Accelerated Exploration of Multi-principal Element Alloys for Structural Applications (Postprint)

DTIC Science & Technology

2015-04-27

SS phases (BCC, HCP and FCC), three silicide phases (M5Si3, M5Si4 and M3Si3), an ordered B2 phase, and two Laves phases (C14 and C15). In total, 453...alloys containing silicide phases (M5Si3, M5Si4, and M3Si2) is probably due to very negative, often below 50 kJ/mol [51 53] enthalpies of formation of...The majority of equiatomic alloys containing two or more phases are (SSþ IM) alloys.5. BCC, HCP and FCC SS phases, three silicide phases (M5Si3, M5Si4

222Rn and 220Rn concentrations in soil gas of Karkonosze-Izera Block (Sudetes, Poland).

PubMed

Malczewski, Dariusz; Zaba, Jerzy

2007-01-01

Soil gas 222Rn and 220Rn concentrations were measured at 18 locations in the Karkonosze-Izera Block area in southwestern Poland. Measurements were carried out in surface air and at sampling depths of 10, 40 and 80 cm. Surface air 222Rn concentrations ranged from 4 to 2160 Bq m(-3) and 220Rn ranged from 4 to 228 Bq m(-3). The concentrations for 10 and 40 cm varied from 142 Bq m(-3) to 801 kBq m(-3) and 102 Bq m(-3) to 64 kBq m(-3) for 222Rn and 220Rn, respectively. At 80 cm 222Rn concentrations ranged from 94 Bq m(-3) to >1 MBq m(-3). The 220Rn concentrations at 80 cm varied from 45 Bq m(-3) to 48 kBq m(-3). The concentration versus depth profiles for 222Rn differed for soils developed on fault zones, uranium deposits or both. Atmospheric air temperature and soil gas 222Rn and 220Rn were negatively correlated. At sampling sites with steep slopes, 220Rn concentrations decreased with depth.

Enhancement of lettuce yield by manipulation of light and nitrogen nutrition

NASA Technical Reports Server (NTRS)

Knight, S. L.; Mitchell, C. A.

1983-01-01

Several levels of photosynthetic photon flux density (PPFD) were tested for effects on growth of 4 cultivars of lettuce (Lactuca sativa L.) under controlled-environment conditions. Growth of 'Salad Bowl', 'Bibb', and 'Ruby' was greater at 932 micromoles s-1 m-2 than at < or = 644 micromoles s-1 m-2 under a 16-hour photoperiod. Thirty mM NO3- or 5 mM NH4+ + 25 mM NO3- increased leaf dry weight while reducing leaf chlorosis in 'Salad Bowl' and 'Grand Rapids' relative to that with 15 mM NO3-, and reduced leaf purpling in 'Bibb' and 'Ruby' with little or no effect on yield. Continuous illumination with 455 or 918 micromoles s-1 m-2 stimulated yield of 'Salad Bowl' and 'Bibb' when 30 mM N as NH4+ + NO3- was used relative to that with 15 mM NO3-.

M3 cholinoreceptors alter electrical activity of rat left atrium via suppression of L-type Ca2+ current without affecting K+ conductance.

PubMed

Filatova, Tatiana S; Naumenko, Nikolay; Galenko-Yaroshevsky, Pavel A; Abramochkin, Denis V

2017-05-01

Electrophysiological effects produced by selective activation of M3 cholinoreceptors were studied in isolated left atrium preparations from rat using the standard sharp glass microelectrode technique. The stimulation of M3 receptors was obtained by application of muscarinic agonist pilocarpine (10 -5  M) in the presence of selective M2 antagonist methoctramine (10 -7  M). Stimulation of M3 receptors induced marked reduction of action potential duration by 14.4 ± 2.4% and 16.1 ± 2.5% of control duration measured at 50 and 90% of repolarization, respectively. This effect was completely abolished by selective M3 blocker 4-DAMP (10 -8  M). In isolated myocytes obtained from the rat left atrium, similar pharmacological stimulation of M3 receptors led to suppression of peak L-type calcium current by 13.9 ± 2.6% of control amplitude (measured at +10 mV), but failed to affect K + currents I to , I Kur , and I Kir . In the absence of M2 blocker methoctramine, pilocarpine (10 -5  M) produced stronger attenuation of I CaL and induced an increase in I Kir . This additive inward rectifier current could be abolished by highly selective blocker of K ir 3.1/3.4 channels tertiapin-Q (10 -6  M) and therefore was identified as I KACh . Thus, in the rat atrial myocardium activation of M3 receptors leads to shortening of action potentials via suppression of I CaL , but does not enhance the major potassium currents involved in repolarization. Joint stimulation of M2 and M3 receptors produces stronger action potential shortening due to M2-mediated activation of I KACh.

Muscarinic acetylcholine receptor subtype 4 is essential for cholinergic stimulation of duodenal bicarbonate secretion in mice - relationship to D cell/somatostatin.

PubMed

Takeuchi, K; Kita, K; Takahashi, K; Aihara, E; Hayashi, S

2015-06-01

We investigated the roles of muscarinic (M) acetylcholine receptor subtype in the cholinergic stimulation of duodenal HCO3(-) secretion using knockout (KO) mice. Wild-type and M1-M5 KO C57BL/6J mice were used. The duodenal mucosa was mounted on an Ussing chamber, and HCO3(-) secretion was measured at pH 7.0 using a pH-stat method in vitro. Carbachol (CCh) or other agents were added to the serosal side. CCh dose-dependently stimulated HCO3(-) secretion in wild-type mice, and this effect was completely inhibited in the presence of atropine. The HCO3(-) response to CCh in wild-type mice was also inhibited by pirenzepine (M1 antagonist), 4DAMP (M3 antagonist), and tropicamide (M4 antagonist), but not by methoctramine (M2 antagonist). CCh stimulated HCO3(-) secretion in M2 and M5 KO animals as effectively as in WT mice; however, this stimulatory effect was significantly attenuated in M1, M3, and M4 KO mice. The decrease observed in the CCh-stimulated HCO3(-) response in M4 KO mice was reversed by the co-application of CYN154806, a somatostatin receptor type 2 (SST2) antagonist. Octreotide (a somatostatin analogue) decreased the basal and CCh-stimulated secretion of HCO3(-) in wild-type mice. The co-localized expression of somatostatin and M4 receptors was confirmed immunohistologically in the duodenum. We concluded that the duodenal HCO3(-) response to CCh was directly mediated by M1/M3 receptors and indirectly modified by M4 receptors. The activation of M4 receptors was assumed to inhibit the release of somatostatin from D cells and potentiate the HCO3(-) response by removing the negative influence of somatostatin via the activation of SST2 receptors.

Superconductivity in the 2-Dimensional Homologous Series AMm Bi3 Q5+m (m=1, 2) (A=Rb, Cs; M=Pb, Sn; Q=Se, Te).

PubMed

Malliakas, Christos D; Chung, Duck Young; Claus, Helmut; Kanatzidis, Mercouri G

2018-05-17

Superconductivity in the two-dimensional AM m Bi 3 Q 5+m family of semimetals is reported. The AMBi 3 Te 6 (m=1) and AM 2 Bi 3 Te 7 (m=2) members of the homologous series with A=Rb, Cs and M=Pb, Sn undergo a bulk superconducting transition ranging from 2.7 to 1.4 K depending on the composition. The estimated superconducting volume fraction is about 90 %. Superconducting phase diagrams as a function of chemical pressure are constructed for the solid solution products of each member of the homologous series, AMBi 3-x Sb x Te 6-y Se y and AM 2 Bi 3-x Sb x Te 7-y Se y (0≤x≤3 or 0≤y≤2). The structural flexibility of the ternary AM m M' 3 Te 5+m semiconducting homology to form isostructural analogues with a variety of metals, M=Pb, Sn; M'=Bi, Sb, gives access to a large number of electronic configurations and superconductivity due to chemical pressure effects. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization and receptor specific toxicity of two diphtheria toxin-related interleukin-3 fusion proteins DAB389-mIL-3 and DAB389-(Gly4Ser)2-mIL-3.

PubMed

Liger, D; vanderSpek, J C; Gaillard, C; Cansier, C; Murphy, J R; Leboulch, P; Gillet, D

1997-04-07

We have constructed two fusion proteins, DAB389-mIL-3 and DAB389-(Gly4Ser)2-mIL-3, in which the receptor-binding domain of diphtheria toxin is replaced by mouse interleukin-3 (IL-3). Cytotoxic activity of the fusion toxins was observed on three out of six cell lines assayed. This toxicity was mediated through binding to the IL-3 receptor as it was inhibited in a dose-dependent manner with murine IL-3 or anti-IL-3 neutralizing antibodies. DAB389-(Gly4Ser)2-mIL-3 was up to 5 times more toxic than DAB389-mIL-3, depending on the cell line (0.8 x 10(-10) M < IC50 < 3 x 10(-10) M). These proteins can be used for the detection of IL-3 receptors on mouse cells and should allow for the selective elimination of IL-3 receptor-positive pluripotent hematopoietic stem cells prior to bone marrow transplantation.

Mettl3 Mutation Disrupts Gamete Maturation and Reduces Fertility in Zebrafish.

PubMed

Xia, Hui; Zhong, Chengrong; Wu, Xingxing; Chen, Ji; Tao, Binbin; Xia, Xiaoqin; Shi, Mijuan; Zhu, Zuoyan; Trudeau, Vance L; Hu, Wei

2018-02-01

N 6 -methyladenosine (m 6 A), catalyzed by Mettl3 methyltransferase, is a highly conserved epigenetic modification in eukaryotic messenger RNA (mRNA). Previous studies have implicated m 6 A modification in multiple biological processes, but the in vivo function of m 6 A has been difficult to study, because mettl3 mutants are embryonic lethal in both mammals and plants. In this study, we have used transcription activator-like effector nucleases and generated viable zygotic mettl3 mutant, Z mettl3 m/m , in zebrafish. We find that the oocytes in Z mettl3 m/m adult females are stalled in early development and the ratio of full-grown stage (FG) follicles is significantly lower than that of wild type. Human chorionic gonadotropin-induced ovarian germinal vesicle breakdown in vitro and the numbers of eggs ovulated in vivo are both decreased as well, while the defects of oocyte maturation can be rescued by sex hormone in vitro and in vivo In Z mettl3 m/m adult males, we find defects in sperm maturation and sperm motility is significantly reduced. Further study shows that 11-ketotestosterone (11-KT) and 17β-estradiol (E2) levels are significantly decreased in Z mettl3 m/m , and defective gamete maturation is accompanied by decreased overall m 6 A modification levels and disrupted expression of genes critical for sex hormone synthesis and gonadotropin signaling in Z mettl3 m/m Thus, our study provides the first in vivo evidence that loss of Mettl3 leads to failed gamete maturation and significantly reduced fertility in zebrafish. Mettl3 and m 6 A modifications are essential for optimal reproduction in vertebrates. Copyright © 2018 by the Genetics Society of America.

A novel muscarinic receptor-independent mechanism of KCNQ2/3 potassium channel blockade by Oxotremorine-M.

PubMed

Zwart, Ruud; Reed, Hannah; Clarke, Sophie; Sher, Emanuele

2016-11-15

Inhibition of KCNQ (Kv7) potassium channels by activation of muscarinic acetylcholine receptors has been well established, and the ion currents through these channels have been long known as M-currents. We found that this cross-talk can be reconstituted in Xenopus oocytes by co-transfection of human recombinant muscarinic M1 receptors and KCNQ2/3 potassium channels. Application of the muscarinic acetylcholine receptor agonist Oxotremorine-methiodide (Oxo-M) between voltage pulses to activate KCNQ2/3 channels caused inhibition of the subsequent KCNQ2/3 responses. This effect of Oxo-M was blocked by the muscarinic acetylcholine receptor antagonist atropine. We also found that KCNQ2/3 currents were inhibited when Oxo-M was applied during an ongoing KCNQ2/3 response, an effect that was not blocked by atropine, suggesting that Oxo-M inhibits KCNQ2/3 channels directly. Indeed, also in oocytes that were transfected with only KCNQ2/3 channels, but not with muscarinic M1 receptors, Oxo-M inhibited the KCNQ2/3 response. These results show that besides the usual muscarinic acetylcholine receptor-mediated inhibition, Oxo-M also inhibits KCNQ2/3 channels by a direct mechanism. We subsequently tested xanomeline, which is a chemically distinct muscarinic acetylcholine receptor agonist, and oxotremorine, which is a close analogue of Oxo-M. Both compounds inhibited KCNQ2/3 currents via activation of M1 muscarinic acetylcholine receptors but, in contrast to Oxo-M, they did not directly inhibit KCNQ2/3 channels. Xanomeline and oxotremorine do not contain a positively charged trimethylammonium moiety that is present in Oxo-M, suggesting that such a charged moiety could be a crucial component mediating this newly described direct inhibition of KCNQ2/3 channels. Copyright © 2016 Elsevier B.V. All rights reserved.

Inventory of File sref.t03z.pgrb197.mean_ds_3hrly.grib

Science.gov Websites

3 hour fcst U-Component of Wind [m/s] wt ens-mean 002 10 m above ground VGRD 3 hour fcst V-Component of Wind [m/s] wt ens-mean 003 2 m above ground TMP 3 hour fcst Temperature [K] wt ens-mean 004 2 m above ground SPFH 3 hour fcst Specific Humidity [kg/kg] wt ens-mean 005 10 m above ground WIND 3 hour

Isolation and identification of metabolites of osthole in rats.

PubMed

Lv, X; Wang, C-Y; Hou, J; Zhang, B-J; Deng, S; Tian, Y; Huang, S-S; Zhang, H-L; Shu, X-H; Zhen, Y-H; Liu, K-X; Yao, J-H; Ma, X-C

2012-11-01

Osthole (Ost), one of the major components of Cnidium monnieri (L.) Cusson, is had the structure of an isopentenoxy-coumarin with a range of pharmacological activities. In the present study, the metabolism of Ost in male Sprague-Dawley rats was investigated by identifying Ost metabolites excreted in rat urine. Following an oral dose of 40 mg/kg Ost, 10 phase I and 3 phase II metabolites were isolated from the urine of rats, and their structures identified on the basis of a range of spectroscopic data, including 2D-NMR techniques. These metabolites were fully characterized as 5'-hydroxyl-osthole (M-1), osthenol (M-2), 4'-hydroxyl-osthole (M-3), 3, 5'-dihydroxyl-osthole (M-4), 5'-hydroxyl-osthenol (M-5), 4'-hydroxyl-2', 3'-dihydro-osthenol (M-6), 4'-hydroxyl-osthenol (M-7), 3, 4'-dihydroxyl-osthole (M-8), 2', 3'-dihydroxyl-osthole (M-9), 5'-hydroxyl-2', 3'-dihydroosthole (M-10), osthenol-7-O-β-D-glucuronide (M-11), osthole-4'-O-β-D-glucuronide (M-12) and osthole-5'-O-β-D-glycuronate (M-13). This is the first identification of M-1, M-3 to M-13 in vivo. On the basis of the metabolites profile, a possible metabolic pathway for Ost metabolism in rats has been proposed. This is the first systematic study on the phases I and II metabolites of 8-isopentenoxy-coumarin derivative.

Effects of culture media and energy sources on the inhibition of nuclear maturation in bovine oocytes.

PubMed

Bilodeau-Goeseels, Sylvie

2006-07-15

The influence of the culture medium and energy sources on spontaneous nuclear maturation and inhibition of maturation in bovine cumulus-enclosed oocytes (CEO) was examined. CEO were cultured in Medium 199, minimum essential medium, M16, or synthetic oviduct fluid (SOF), all containing 3 mg/mL bovine serum albumin (BSA), and SOF without BSA, alone or supplemented with hypoxanthine (HYPO, 4 mM) or forskolin (FSK, 100 microM) for 21 h. More CEO remained at the GV stage in M16 compared to other media (P < 0.05). Supplementation with HYPO increased and FSK reduced the percentage of CEO remaining at the GV stage (P < 0.05) only in M16. The effects of energy sources, in the absence or presence of HYPO or FSK, were examined in CEO cultured in M16 salts+PVA. Glucose (0.5 and 5.5 mM), pyruvate (0.32 and 3.2 mM), lactate (3.3 mM) and glutamine (1.3 mM) significantly reduced the percentage of CEO remaining at the GV stage compared to M16 salts alone; only glutamine significantly increased the percentage of CEO at the MII stage compared to M16 salts. In M16 salts+HYPO, glucose (0.5 mM), pyruvate (0.32 mM), lactate (3.3 mM) and glutamine (1.3 mM) significantly reduced the percentage of GV and degenerate oocytes and increased the percentage of CEO at the MI stage. In M16 salts+FSK, the energy sources significantly decreased the percentage of oocytes with condensed chromosomes and increased the percentage of CEO reaching metaphase I. In conclusion, meiotic inhibitors had different effects in different culture media and glucose, pyruvate, lactate and glutamine were stimulatory to nuclear maturation. It was noteworthy that some of the results obtained were contrary to previous findings in mouse oocytes.

The guinea pig ileum lacks the direct, high-potency, M(2)-muscarinic, contractile mechanism characteristic of the mouse ileum.

PubMed

Griffin, Michael T; Matsui, Minoru; Ostrom, Rennolds S; Ehlert, Frederick J

2009-10-01

We explored whether the M(2) muscarinic receptor in the guinea pig ileum elicits a highly potent, direct-contractile response, like that from the M(3) muscarinic receptor knockout mouse. First, we characterized the irreversible receptor-blocking activity of 4-DAMP mustard in ileum from muscarinic receptor knockout mice to verify its M(3) selectivity. Then, we used 4-DAMP mustard to inactivate M(3) responses in the guinea pig ileum to attempt to reveal direct, M(2) receptor-mediated contractions. The muscarinic agonist, oxotremorine-M, elicited potent contractions in ileum from wild-type, M(2) receptor knockout, and M(3) receptor knockout mice characterized by negative log EC(50) (pEC (50)) values +/- SEM of 6.75 +/- 0.03, 6.26 +/- 0.05, and 6.99 +/- 0.08, respectively. The corresponding E (max) values in wild-type and M(2) receptor knockout mice were approximately the same, but that in the M(3) receptor knockout mouse was only 36% of wild type. Following 4-DAMP mustard treatment, the concentration-response curve of oxotremorine-M in wild-type ileum resembled that of the M(3) knockout mouse in terms of its pEC (50), E (max), and inhibition by selective muscarinic antagonists. Thus, 4-DAMP mustard treatment appears to inactivate M(3) responses selectively and renders the muscarinic contractile behavior of the wild-type ileum similar to that of the M(3) knockout mouse. Following 4-DAMP mustard treatment, the contractile response of the guinea pig ileum to oxotremorine-M exhibited low potency and a competitive-antagonism profile consistent with an M(3) response. The guinea pig ileum, therefore, lacks a direct, highly potent, M(2)-contractile component but may have a direct, lower potency M(2) component.

In vitro metabolism of the anti-androgenic fungicide vinclozolin by rat liver microsomes.

PubMed

Sierra-Santoyo, Adolfo; Angeles-Soto, Esperanza; de Lourdes López-González, Ma; Harrison, Randy A; Hughes, Michael F

2012-03-01

Vinclozolin (V) is a fungicide used in agricultural settings. V administered to rats is hydrolyzed to 2-[[(3,5-dichlorophenyl)-carbamoyl]oxy]-2-methyl-3-butenoic acid (M1) and 3',5'-dichloro-2-hydroxy-2-methylbut-3-enanilide (M2). V, M1 and M2 have antiandrogenic properties by interacting with the androgen receptor. Data on V, M1 and M2 biotransformation are limited. Our objective was to characterize V metabolism by rat liver microsomes. V was incubated with non-treated adult male Long-Evans rat liver microsomes and NADPH. Several metabolites were detected following the extraction of incubate with acetonitrile and analysis by HPLC/DAD/MSD. One metabolite was identified as [3-(3,5-dichlorophenyl)-5-methyl-5-(1,2-dihydroxyethyl)-1,3-oxazolidine-2,4-dione] (M4), which was gradually converted to 3',5'-dichloro-2,3,4-trihydroxy-2-methylbutylanilide (M5). Both co-eluted in the same HPLC peak. Another metabolite ([M7]) was detected by UV but was unstable for mass spectral analysis. The K(M app) for co-eluted M4/M5 and [M7] was 53.7 and 135.4 μM, the V(max app) was 0.812 and 0.669 nmoles/min/mg protein, and CL(int) was 15.1 and 4.9 ml/min/g protein, respectively. Pilocarpine, orphenadrine and proadifen and anti-rat cytochrome P450 (CYP)2A, 2B and 3A antibodies inhibited M4/M5 and [M7] formation. These results indicate that V is efficiently metabolized by CYP. Determination of the metabolites of V will provide further insight into the relationship between toxicity and tissue dose of V and its metabolites.

Influence of unilateral maxillary first molar extraction treatment on second and third molar inclination in Class II subdivision patients.

PubMed

Livas, Christos; Pandis, Nikolaos; Booij, Johan Willem; Halazonetis, Demetrios J; Katsaros, Christos; Ren, Yijin

2016-01-01

To assess the maxillary second molar (M2) and third molar (M3) inclination following orthodontic treatment of Class II subdivision malocclusion with unilateral maxillary first molar (M1) extraction. Panoramic radiographs of 21 Class II subdivision adolescents (eight boys, 13 girls; mean age, 12.8 years; standard deviation, 1.7 years) before treatment, after treatment with extraction of one maxillary first molar and Begg appliances and after at least 1.8 years in retention were retrospectively collected from a private practice. M2 and M3 inclination angles (M2/ITP, M2/IOP, M3/ITP, M3/IOP), constructed by intertuberosity (ITP) and interorbital planes (IOP), were calculated for the extracted and nonextracted segments. Random effects regression analysis was performed to evaluate the effect on the molar angulation of extraction, time, and gender after adjusting for baseline measurements. Time and extraction status were significant predictors for M2 angulation. M2/ITP and M2/IOP decreased by 4.04 (95% confidence interval [CI]: -6.93, 1.16; P  =  .001) and 3.67 (95% CI: -6.76, -0.58; P  =  .020) in the extraction group compared to the nonextraction group after adjusting for time and gender. The adjusted analysis showed that extraction was the only predictor for M3 angulation that reached statistical significance. M3 mesial inclination increased by 7.38° (95% CI: -11.2, -3.54; P < .001) and 7.33° (95% CI: -11.48, -3.19; P  =  .001). M2 and M3 uprighting significantly improved in the extraction side after orthodontic treatment with unilateral maxillary M1 extraction. There was a significant increase in mesial tipping of maxillary second molar crowns over time.

Muscarinic receptor subtypes involved in carbachol-induced contraction of mouse uterine smooth muscle.

PubMed

Kitazawa, Takio; Hirama, Ryuichi; Masunaga, Kozue; Nakamura, Tatsuro; Asakawa, Koichi; Cao, Jinshan; Teraoka, Hiroki; Unno, Toshihiro; Komori, Sei-ichi; Yamada, Masahisa; Wess, Jürgen; Taneike, Tetsuro

2008-06-01

Functional muscarinic acetylcholine receptors present in the mouse uterus were characterized by pharmacological and molecular biological studies using control (DDY and wild-type) mice, muscarinic M2 or M3 single receptor knockout (M2KO, M3KO), and M2 and M3 receptor double knockout mice (M2/M3KO). Carbachol (10 nM-100 microM) increased muscle tonus and phasic contractile activity of uterine strips of control mice in a concentration-dependent manner. The maximum carbachol-induced contractions (Emax) differed between cervical and ovarian regions of the uterus. The stage of the estrous cycle had no significant effect on carbachol concentration-response relationships. Tetrodotoxin did not decrease carbachol-induced contractions, but the muscarinic receptor antagonists (11-[[2-[(diethylaminomethyl)-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b[2,3-b][1,4]benzodiazepin6-one (AF-DX116), N-[2-[2-[(dipropylamino)methyl]-1-piperidinyl]ethyl]-5,6-dihydro-6-oxo-11H-pyrido[2,3-b][1,4] benzodiazepine-11-carboxamide (AF-DX384), 4-diphenylacetoxy-N-methyl-piperidine(4-DAMP), para-fluoro-hexa hydro-sila-diphenidol (p-F-HHSiD), himbacine, methoctramine, pirenzepine, and tropicamide) inhibited carbachol-induced contractions in a competitive fashion. The pKb values for these muscarinic receptor antagonists correlated well with the known pKi values of these antagonists for the M3 muscarinic receptor. In uterine strips isolated from mice treated with pertussis toxin (100 microg/kg, i.p. for 96 h), Emax values for carbachol were significantly decreased, but effective concentration that caused 50% of Emax values (EC50) remained unchanged. In uterine strips treated with 4-DAMP mustard (30 nM) and AF-DX116 (1 microM), followed by subsequent washout of AF-DX116, neither carbachol nor N,N,N,-trimethyl-4-(2-oxo-1-pyrolidinyl)-2-butyn-1-ammonium iodide (oxotremorine-M) caused any contractile responses. Both M2 and M3 muscarinic receptor messenger RNAs were detected in the mouse uterus via reverse transcription polymerase chain reaction. Carbachol also caused contraction of uterine strips isolated from M2KO mice, but the concentration-response curve was shifted to the right and downward compared with that for the corresponding wild-type mice. On the other hand, uterine strips isolated from M3KO and M2/M3 double KO mice were virtually insensitive to carbachol. In conclusion, although both M2 and M3 muscarinic receptors were expressed in the mouse uterus, carbachol-induced contractile responses were predominantly mediated by the M3 receptor. Activation of M2 receptors alone did not cause uterine contractions; however, M2 receptor activation enhanced M3 receptor-mediated contractions in the mouse uterus.

77 FR 42484 - Civil Nuclear Trade Advisory Committee (CINTAC) Public Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-19

... a.m. Eastern Daylight Time (EDT). The public session is from 3:00 p.m.- 4:00 p.m. ADDRESSES: The..., 2012 CINTAC meeting is as follows: Closed Session (9:00 a.m.-3:00 p.m.) 1. Discussion of matters... found in 5 U.S.C. App. (10)(a)(1) and 10(a)(3). Public Session (3:00 p.m.-4:00 p.m.) 1. International...

Structure determination of metabolites isolated from urine and bile after administration of AY4166, a novel D-phenylalanine-derivative hypoglycemic agent.

PubMed

Takesada, H; Matsuda, K; Ohtake, R; Mihara, R; Ono, I; Tanaka, K; Naito, M; Yatagai, M; Suzuki, E

1996-10-01

Molecular structures of 10 metabolites, which were isolated from urine (M1-M8) or bile (M9 and M10) after administration of AY4166 (N-(trans-4-isopropylcyclohexanecarbonyl)-D-phenylalanine), a novel amino acid derivative with hypoglycemic activity, have been elucidated by mass spectrometry and nuclear magnetic resonance. Four of these (M1, M2, M3 and M8) were determined to be hydroxyl derivatives of AY4166, two (M9 and M10) were carboxylate derivatives via oxidization of M2 and M3, three (M4, M5 and M6) were glucronic acid conjugates and the other (M7) was a dehydro derivative. The estimated structures for M1, M2, M3, M7, M8, M9 and M10 were confirmed by the coincidence of the retention time of HPLC, MS and 1H NMR spectra between the isolated metabolites and authentic synthesized substances. For three glucronic acid conjugates, M4, M5 and M6, structural confirmation was performed by a selective enzymatic digestion with beta-glucronidase. M1 and M2/3 were about 5-6 and 3 times less potent than AY4166, respectively, and M7 was almost as potent as AY4166.

Impact of PNPLA3 variants on liver histology of 168 patients with HIV infection and chronic hepatitis C.

PubMed

Sagnelli, C; Merli, M; Uberti-Foppa, C; Hasson, H; Cirillo, G; Grandone, A; Salpietro, S; Minichini, C; Del Giudice, E M; Lazzarin, A; Sagnelli, E; Coppola, N

2016-04-01

This study analysed the impact of PNPLA3 variants on liver histology of 168 HIV/hepatitis C virus (HCV)-coinfected patients who were naïve for HCV treatment. A athologist unaware of the patients' condition graded liver fibrosis and necroinflammation (Ishak) and steatosis (Kleiner). Patients were tested for PNPLA3 variants and genotyped for the PNPLA3 rs738409 C to G variant underlying the I148M substitution. All were hepatitis B surface antigen negative and stated no alcohol abuse. The mean age was 40.6 (37.6-44.1) years, 72.6% were males, 42% had HCV genotype 3, 38.9% HCV genotype 1 and 79.2% were receiving highly active antiretroviral therapy. The 79 patients with the PNPLA3 p.148I/M or M/M variants more frequently showed severe steatosis (score 3-4) than the 89 with PNPLA3 p.148I/I (43% vs. 24.7%, p 0.001), whereas no difference was observed in the degree of necroinflammation or fibrosis. Compared with 112 patients with lower scores, 56 with severe steatosis showed higher body mass index (p 0.03), higher rate of HCV genotype 3 (55.6% vs. 35.2%, p 0.01), PNPLA3 p.148I/M or M/M (60.7% vs. 39.3%, p 0.01) and lower CD4(+) cells/mm(3) (514.00 (390.5-673.0) vs. 500.00 (399.0-627.0); p 0.002). At multivariate analysis, body mass index (p 0.01), HCV genotype 3 (p 0.006), CD4(+) cell count (p 0.005) and PNPLA3 p.148I/M or M/M variants (p 0.01) were found to be independent predictors of severe liver steatosis. The PNPLA3 p.148 I/M or M/M variants and CD4(+) cell count were the only independent predictors of severe steatosis in patients with HCV non-3 genotypes. This is the first study to show that among HIV/HCV-coinfected patients the PNPLA3 p.148I/M or M/M variant have substantially less impact on steatosis for those with HCV genotype 3 than non-genotype 3. Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Efficiency evaluation of agricultural underground dam in South Korea

NASA Astrophysics Data System (ADS)

Myoung, W.; Song, S. H.; Yong, H. H.

2017-12-01

Climate change has resulted in severe droughts in a rice-planting season (i.e., April to June) in South Korea since 2012. Therefore, all time high-amount water resources in rice-farming seasons (i.e., April to October) were required against natural crises like droughts. The underground dam, which is able to increase groundwater amounts in the alluvium aquifer, has been considered to be an alternative for securing more groundwater resources. In this study, irrigation efficiencies of five pre-existing agricultural underground dams in South Korea were evaluated during the drought periods. A total amount of groundwater storage capacities in alluvial aquifers of these five ones were estimated approximate 15 × 107 m3: above 4 × 106 m3 for two underground dams (Ian, Namsong), 2 3 × 106 m3, for 2 dams (Oksung, Wooil), below 2 × 106 m3 for 1 dam (Gocheon), respectively. Irrigating amounts of groundwater accounted for three underground dams (Ian, Namsong, Gocheon), supplied in rice-farming season are 8.5 × 105 m3/year, 8.3 × 105 m3/year, 6.3 × 105 m3/year, respectively. The total demand of agricultural water in these underground dams is 2.0 × 106 m3/year, 1.9 × 106 m3/year, 2.2 × 106 m3/year, respectively. Irrigating amounts of groundwater accounted for whole of rice-farming area in South Korea is 4.3 × 108 m3/year whereas total demand of agricultural water is 9.4 × 109 m3/year. Groundwater were pumped from the radial collector wells located in the upstream from the underground dams. Oksung underground dam, one representative underground dam located in Chungnam province in South Korea, irrigated approximate 3 × 105 m3 during a dried rice-planting season (between April to June) in 2017. It was three times more than usual (9 × 104 m3). Groundwater levels during the same period maintained above 5.55 m, which was slightly lower than usual (6.00 m). Results of Oksung underground dam demonstrated that underground dams in South Korea were effectively operated against drought. Recently, Korea Rural Community Corporation, a governmental institute of South Korea, plans to construct more underground dams against drought.

Radiological risk assessment of environmental radon

NASA Astrophysics Data System (ADS)

Khalid, Norafatin; Majid, Amran Ab; Yahaya, Redzuwan; Yasir, Muhammad Samudi

2013-11-01

Measurements of radon gas (222Rn) in the environmental are important to assess indoor air quality and to study the potential risk to human health. Generally known that exposure to radon is considered the second leading cause of lung cancer after smoking. The environmental radon concentration depends on the 226Ra concentration, indoor atmosphere, cracking on rocks and building materials. This study was carried out to determine the indoor radon concentration from selected samples of tin tailings (amang) and building materials in an airtight sealed homemade radon chamber. The radiological risk assessment for radon gas was also calculated based on the annual exposure dose, effective dose equivalent, radon exhalation rates and fatal cancer risk. The continuous radon monitor Sun Nuclear model 1029 was used to measure the radon concentration emanates from selected samples for 96 hours. Five types of tin tailings collected from Kampar, Perak and four samples of building materials commonly used in Malaysia dwellings or building constructions were analysed for radon concentration. The indoor radon concentration determined in ilmenite, monazite, struverite, xenotime and zircon samples varies from 219.6 ± 76.8 Bq m-3 to 571.1 ± 251.4 Bq m-3, 101.0 ± 41.0 Bq m-3 to 245.3 ± 100.2 Bq m-3, 53.1 ± 7.5 Bq m-3 to 181.8 ± 9.7 Bq m-3, 256.1 ± 59.3 Bq m-3 to 652.2 ± 222.2 Bq m-3 and 164.5 ± 75.9 Bq m-3 to 653.3 ± 240.0 Bq m-3, respectively. Whereas, in the building materials, the radon concentration from cement brick, red-clay brick, gravel aggregate and cement showed 396.3 ± 194.3 Bq m-3, 192.1 ± 75.4 Bq m-3, 176.1 ± 85.9 Bq m-3 and 28.4 ± 5.7 Bq m-3, respectively. The radon concentration in tin tailings and building materials were found to be much higher in xenotime and cement brick samples than others. All samples in tin tailings were exceeded the action level for radon gas of 148 Bq m-3 proposed by EPA except monazite 0.15 kg, struverite 0.15 kg and 0.25 kg. Whereas, all building material samples have exceeded the radon concentration in concrete and building materials of 3 to 7 Bq m-3 estimated by ICRP. The annual effective dose, effective dose equivalent, and radon exhalation rates in tin tailings were calculated to be in the range of 2.47 to 11.46 mSv, 5.94 to 1090.56 mSv y-1, and 0.23 to 1.18 mBq kg-1 h-1. For building materials, the calculated risk assessment of the annual effective dose, effective dose equivalent, radon exhalation rates and fatal cancer risk were 0.72 to 10.00 mSv, 1.73 to 24.00 mSv y-1, 0.010 to 0.06 mBq kg-1 h-1 and 40 to 550 chances of persons will suffer the cancer per million (1 × 106), respectively.

Cyclic variations in nitrogen uptake rate of soybean plants: effects of pH and mixed nitrogen sources

NASA Technical Reports Server (NTRS)

Raper, C. D. Jr; Vessey, J. K.; Henry, L. T.; Chaillou, S.

1991-01-01

To determine if the daily pattern of NO3- and NH4+ uptake is affected by acidity or NO3- : NH4+ ratio of the nutrient solution, non-nodulated soybean plants (Glycine max) were exposed for 21 days to replenished, complete nutrient solutions at pH 6.0, 5.5, 5.0, and 4.5 which contained either 1.0 mM NH4+, 1.0 mM NO3- [correction of NO3+], 0.67 mM NH4+ plus 0.33 mM NO3- (2:1 NH4+ : NO3-) [correction of (2:1 NH3+ : NO4-)], or 0.33 mM NH4+ plus 0.67 mM NO3- (1:2 NH4+ : NO3-). Net uptake rates of NH4+ and NO3- were measured daily by ion chromatography as depletion from the replenished solutions. When NH4+ and NO3- were supplied together, cumulative uptake of total nitrogen was not affected by pH or solution NH4+ : NO3- ratio. The cumulative proportion of nitrogen absorbed as NH4+ decreased with increasing acidity; however, the proportional uptake of NH4+ and NO3- was not constant, but varied day-to-day. This day-to-day variation in relative proportions of NH4+ and NO3- absorbed when NH4+ : NO3- ratio and pH of solution were constant indicates that the regulatory mechanism is not directly competitive. Regardless of the effect of pH on cumulative uptake of NH4+, the specific nitrogen uptake rates from mixed and from individual NH4+ and NO3- sources oscillated between maxima and minima at each pH with average periodicities similar to the expected interval of leaf emergence.

Conversion of 2,3-butanediol to butadiene

DOEpatents

Lilga, Michael A.; Frye, Jr, John G.; Lee, Suh-Jane; Albrecht, Karl O.

2016-09-06

A composition comprising 2,3-butanediol is dehydrated to methyl vinyl carbinol and/or 1,3-butadiene by exposure to a catalyst comprising (a) M.sub.xO.sub.y wherein M is a rare earth metal, a group IIIA metal, Zr, or a combination thereof, and x and y are based upon an oxidation state of M, or (b) M.sup.3.sub.a(PO.sub.4).sub.b where M.sup.3 is a group IA, a group IIA metal, a group IIIA metal, or a combination thereof, and a and b are based upon the oxidation state of M.sup.3. Embodiments of the catalyst comprising M.sub.xO.sub.y may further include M.sup.2, wherein M.sup.2 is a rare earth metal, a group IIA metal, Zr, Al, or a combination thereof. In some embodiments, 2,3-butanediol is dehydrated to methyl vinyl carbinol and/or 1,3-butadiene by a catalyst comprising M.sub.xO.sub.y, and the methyl vinyl carbinol is subsequently dehydrated to 1,3-butadiene by exposure to a solid acid catalyst.

The PNPLA3 variant associated with fatty liver disease (I148M) accumulates on lipid droplets by evading ubiquitylation

PubMed Central

BasuRay, Soumik; Smagris, Eriks

2017-01-01

A sequence variation (I148M) in patatin‐like phospholipase domain‐containing protein 3 (PNPLA3) is strongly associated with fatty liver disease, but the underlying mechanism remains obscure. In this study, we used knock‐in (KI) mice (Pnpla3148M/M) to examine the mechanism responsible for accumulation of triglyceride (TG) and PNPLA3 in hepatic lipid droplets (LDs). No differences were found between Pnpla3148M/M and Pnpla3+/+ mice in hepatic TG synthesis, utilization, or secretion. These results are consistent with TG accumulation in the Pnpla3148M/M mice being caused by impaired TG mobilization from LDs. Sucrose feeding, which is required to elicit fatty liver in KI mice, led to a much larger and more persistent increase in PNPLA3 protein in the KI mice than in wild‐type (WT) mice. Inhibition of the proteasome (bortezomib), but not macroautophagy (3‐methyladenine), markedly increased PNPLA3 levels in WT mice, coincident with the appearance of ubiquitylated forms of the protein. Bortezomib did not increase PNPLA3 levels in Pnpla3148M/M mice, and only trace amounts of ubiquitylated PNPLA3 were seen in these animals. Conclusion: These results are consistent with the notion that the 148M variant disrupts ubiquitylation and proteasomal degradation of PNPLA3, resulting in accumulation of PNPLA3‐148M and impaired mobilization of TG from LDs. (Hepatology 2017;66:1111‐1124). PMID:28520213

Mechanisms for the reactions of group 10 transition metal complexes with metal-group 14 element bonds, Bbt(Br)E═M(PCy3)2 (E = C, Si, Ge, Sn, Pb; M = Pd and Pt).

PubMed

Liao, Wei-Hung; Ho, Pei-Yun; Su, Ming-Der

2013-02-04

The electronic structures of the Bbt(Br)E═M(PCy(3))(2) (E = C, Si, Ge, Sn, Pb and M = Pt, Pd) complexes and their potential energy surfaces for the formation and water addition reactions were studied using density functional theory (B3LYP/LANL2DZ). The theoretical evidence suggests that the bonding character of the E═M double bond between the six valence-electron Bbt(Br)E: species and the 14 valence-electron (PCy(3))(2)M complexes has a predominantly high s-character. That is, on the basis of the NBO, this theoretical study indicates that the σ-donation from the E element to the M atom prevails. Also, theoretical computations suggest that the relative reactivity decreases in the order: Bbt(Br)C═M(PCy(3))(2) > Bbt(Br)Si═M(PCy(3))(2) > Bbt(Br)Ge═M(PCy(3))(2) > Bbt(Br)Sn═M(PCy(3))(2) > Bbt(Br)Pb═M(PCy(3))(2), irrespective of whether M = Pt or M = Pd is chosen. Namely, the greater the atomic weight of the group 14 atom (E), the larger is the atomic radius of E and the more stable is its Bbt(Br)E═M(PCy(3))(2) doubly bonded species toward chemical reactions. The computational results show good agreement with the available experimental observations. The theoretical results obtained in this work allow a number of predictions to be made.

EPR study of chromium-doped forsterite crystals: Cr3+( M1) with associated trivalent ions Al3+ and Sc3+

NASA Astrophysics Data System (ADS)

Ryabov, I. D.

2012-10-01

Electron paramagnetic resonance (EPR) study of single crystals of forsterite co-doped with chromium and scandium has revealed, apart from the known paramagnetic centers Cr3+( M1) and Cr3+( M1)- V_{{{{Mg}}^{2 + } }} ( M2) (Ryabov in Phys Chem Miner 38:177-184, 2011), a new center Cr3+( M1)- V_{{{{Mg}}^{2 + } }} ( M2)-Sc3+ formed by a Cr3+ ion substituting for Mg2+ at the M1 structural position with a nearest-neighbor Mg2+ vacancy at the M2 position and a Sc3+ ion presumably at the nearest-neighbor M1 position. For this center, the conventional zero-field splitting parameters D and E and the principal g values have been determined as follows: D = 33,172(29) MHz, E = 8,482(13) MHz, g = [1.9808(2), 1.9778(2), 1.9739(2)]. The center has been compared with the known ion pair Cr3+( M1)-Al3+ (Bershov et al. in Phys Chem Miner 9:95-101, 1983), for which the refined EPR data have been obtained. Based on these data, the known sharp M1″ line at 13,967 cm-1 (with the splitting of 1.8 cm-1), observed in low-temperature luminescence spectra of chromium-doped forsterite crystals (Glynn et al. in J Lumin 48, 49:541-544, 1991), has been ascribed to the Cr3+( M1)-Al3+ center. It has been found that the concentration of the new center increases from 0 up to 4.4 × 1015 mg-1, whereas that of the Cr3+( M1) and Cr3+( M1)- V_{{{{Mg}}^{2 + } }} ( M2) centers quickly decreases from 7.4 × 1015 mg-1 down to 3 × 1015 mg-1 and from 2.7 × 1015 mg-1 down to 0.5 × 1015 mg-1, i.e., by a factor of 2.5 and 5.4, respectively, with an increase of the Sc content from 0 up to 0.22 wt % (at the same Cr content 0.25 wt %) in the melt. When the Sc content exceeds that of Cr, the concentration of the new center decreases most likely due to the formation of the Sc3+( M1)- V_{{{{Mg}}^{2 + } }} ( M2)-Sc3+ complex instead of the Cr3+( M1)- V_{{{{Mg}}^{2 + } }} ( M2)-Sc3+ center. The formation of such ordered neutral complex is in agreement with the experimental results, concerning the incorporation of Sc into olivine, recently obtained by Grant and Wood (Geochim Cosmochim Acta 74:2412-2428, 2010).

Increased intermediate M1-M2 macrophage polarization and improved cognition in mild cognitive impairment patients on ω-3 supplementation.

PubMed

Famenini, Sam; Rigali, Elizabeth A; Olivera-Perez, Henry M; Dang, Johnny; Chang, Michael To; Halder, Ramesh; Rao, Rammohan V; Pellegrini, Matteo; Porter, Verna; Bredesen, Dale; Fiala, Milan

2017-01-01

Monocyte/macrophages of patients with mild cognitive impairment (MCI) and Alzheimer disease (AD) are defective in phagocytosis and degradation amyloid β 1-42 (Aβ 1-42 ), but are improved by ω-3 fatty acids (ω-3s). The hypothesis of this study was that active Aβ 1-42 phagocytosis by macrophages prevents brain amyloidosis and thus maintains cognition. We studied the effects of self-supplementation with a drink with ω-3s, antioxidants, and resveratrol on Mini-Mental State Examination (MMSE) scores, macrophage M1M2 phenotype [the ratio of inflammatory cluster of differentiation (CD)54+CD80 and proresolution markers CD163+CD206], and Aβ 1-42 phagocytosis in patients initially diagnosed as having MCI or subjective cognitive impairment (SCI). At baseline, the median MMSE score in patients in both the apolipoprotein E (ApoE) ε3/ε3 and ApoE ε3/ε4 groups was 26.0 and macrophage Aβ 1-42 phagocytosis was defective. The MMSE rate of change increased in the ApoE ε3/ε3 group a median 2.2 points per year (P = 0.015 compared to 0) but did not change in the ApoE ε3/ε4 group (P = 0.014 between groups). In the ApoE ε3/ε3 group, all patients remained cognitively stable or improved; in the ApoE ε3/ε4 group, 1 recovered from dementia, but 3 lapsed into dementia. The macrophage phenotype polarized in patients bearing ApoE ε3/ε3 to an intermediate (green zone) M1-M2 type at the rate of 0.226 U/yr, whereas in patients bearing ApoE ε3/ε4, polarization was negative (P = 0.08 between groups). The baseline M1M2 type in the extreme M1 (red zone) or M2 (white zone) was unfavorable for cognitive outcome. Aβ 1-42 phagocytosis increased in both ApoE groups (P = 0.03 in each groups). In vitro, the lipidic mediator resolvin D1 (RvD1) down regulated the M1 type in patients with ApoE ε3/ε3 but in some patients with ε3/ε4, paradoxically up-regulated the M1 type. Antioxidant/ω-3/resveratrol supplementation was associated with favorable immune and cognitive responses in ApoE ε3/ε3 and individual patients bearing ApoE ε3/ε4, and brings into personalized clinical practice the immune benefits expected from ω-3 mediators called resolvins. The validity of this study is limited by its small size and uncontrolled design.-Famenini, S., Rigali, E. A., Olivera-Perez, H. M., Dang, J., Chang, M T., Halder, R., Rao, R. V., Pellegrini, M., Porter, V., Bredesen, D., Fiala, M. Increased intermediate M1-M2 macrophage polarization and improved cognition in mild cognitive impairment patients on ω-3 supplementation. © The Author(s).

Tier One: Draft Environmental Impact Statement. Volume 1. Realignment of Mountain Home Air Force Base and Proposed Expanded Range Capability

DTIC Science & Technology

1990-02-01

one of the most valuable assets in the Air Force inventory . This Tier 1 EIS is one tool designed to contribute to the decisionmaking process. The...M3.2-7 M3.2.5 Emission Inventories ...M3.5.3.2 Prehistoric Archaeological Resource Inventory ........................................................... M3.5-4 M3.5.4 Historic and Architectural

Study on OELs for enzyme-containing detergent in China.

PubMed

Zhang, X D; Liang, Y X; Lee, C S; Jin, T Y

2004-01-01

This study is aimed at setting occupational exposure levels for total detergent dust and enzymes in detergent industries. The study population consisted of 795 workers from four enzyme-containing detergent manufacturing plants (A1, A2, B1 and B2), and 156 control workers from an electronic assembly factory. Work environment monitoring was conducted using high volume of air sampler fro measuring the concentration of total dust (mg/m3), and analyzing the level of enzyme (ng/m3) by ELISA method. A standard questionnaires, pulmonary function test, and skin prick test are used to assess health effects. The levels of detergent total dust varied from 0.2 mg/m3 to 12.54 mg/m3. For enzyme levels, in A1, B1 and B2, the concentration ranged from non-detectable to 9.92 ng/m3 and in A2, the concentration was analyzed by enzyme activity methods and was expressed as Gu/m3 (1 Gu/m3 = 16 ng/m3). The concentration is between 0.16-31.36 ng/m3. Non-specific irritation rates in exposed workers were significantly higher than that in controls. Based on the data collected from A1, B1 and control plants, 95% benchmark dose lower bound were calculated as 1.17 mg/m3. The difference of pulmonary function between exposed workers and controls is not significant. The results of SPT showed that neither Savinase- nor Alcalase-induced sensitization was found in controls. The prevalence rates of sensitization for Savinase and Alcalase were ranged between 3.2% and 31% in all enzyme-containing detergent manufacturers investigated. No case of occupational asthma was observed. For total dust, 1 mg/m3 is suggested as permissible concentration-time weighted average (PC-TWA), and 2 mg/m3 as permissible concentration-short term exposure limit (PC-STEL). For the enzyme Subtilisins, 15 ng/m3 is suggested as PC-TWA, and 30 ng/m3 as PC-STEL.

Stability of M 3S 3 complexes on fcc M(111) surfaces: M = Au, Ag, Cu, and Ni

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Da-Jiang; Lee, Jiyoung; Windus, Theresa L.

Density Functional Theory is utilized to assess the stability of metal (M)-sulfur (S) complexes adsorbed on fcc M(111) surfaces, specifically considering S-decorated planar M trimers, M 3S 3. Scanning Tunneling Microscopy studies have identified structures proposed to be Ni 3S 3 on Ni(111), and Au 3S 3 on Au(111). In addition, Cu 3S 3 on Cu(111) has been suggested to facilitate enhanced Cu surface mass transport. Our analysis considers M 3S 3 complexes for M = Au, Ag, Cu, and Ni, assessing key measures of stability on surfaces, and also comparing behavior with trends in gas-phase stability. These surface andmore » gas-phase analyses are systematically related within the framework of Hess’s law, which allows elucidation of various contributions to the overall energetics. In all cases, the adsorbed complex is stable relative to its separated constituents adsorbed on the terrace. However, only for Ag does one find a negative energy of formation from excess S on terraces and M extracted from kink sites along step edges, implying spontaneous complex formation for this pathway. We interpret various experimental observations in the context of our results for energetics.« less

Stability of M 3S 3 complexes on fcc M(111) surfaces: M = Au, Ag, Cu, and Ni

DOE PAGES

Liu, Da-Jiang; Lee, Jiyoung; Windus, Theresa L.; ...

2018-02-08

Density Functional Theory is utilized to assess the stability of metal (M)-sulfur (S) complexes adsorbed on fcc M(111) surfaces, specifically considering S-decorated planar M trimers, M 3S 3. Scanning Tunneling Microscopy studies have identified structures proposed to be Ni 3S 3 on Ni(111), and Au 3S 3 on Au(111). In addition, Cu 3S 3 on Cu(111) has been suggested to facilitate enhanced Cu surface mass transport. Our analysis considers M 3S 3 complexes for M = Au, Ag, Cu, and Ni, assessing key measures of stability on surfaces, and also comparing behavior with trends in gas-phase stability. These surface andmore » gas-phase analyses are systematically related within the framework of Hess’s law, which allows elucidation of various contributions to the overall energetics. In all cases, the adsorbed complex is stable relative to its separated constituents adsorbed on the terrace. However, only for Ag does one find a negative energy of formation from excess S on terraces and M extracted from kink sites along step edges, implying spontaneous complex formation for this pathway. We interpret various experimental observations in the context of our results for energetics.« less

Soldiers’ Toolbox for Developing Tactics, Techniques, and Procedures (TTP)

DTIC Science & Technology

2010-02-01

1-67 AR (M1A2) [Player] • B/1-67 AR (M1A2) [Artificial Intelligence] • C/2-41 IN ( M2A3 ) [Artificial Intelligence] • D/2-41 IN ( M2A3 ) [Artificial...ORGANIZATION: 1-67 AR A/1-67 AR (M1A2) B/1-67 AR (M1A2) C/2-41 IN ( M2A3 ) D/2-41 IN ( M2A3 ) 1. (U) SITUATION 1.A. (U) Enemy forces. 1.A.1. (U...Priority of Maintenance in the Battalion during this operation is M1A2’s, M2A3 ’s, STRYKERs, BFIST, then light tracks and wheels. 4.A.1. BEFORE

Inhibitory effects of ethyl acetate-soluble fraction from morus alba on lipid accumulation in 3T3-L1 cells.

PubMed

Park, Hee-Sook; Shim, Soon-Mi; Kim, Gun-Hee

2013-11-01

Fruits of mulberry (Morus alba) have been widely used for therapeutic purposes in Asian countries for centuries. Treatment of 3T3-L1 cells with ethanolic extracts of M. alba decreased adipocyte differentiation at 100 microg/mL by 18.6%. Treatment suppressed mRNA levels of PPARgamma and C/EBPalpha expression in 3T3-L1 cells. However, the extract did not change free glycerol release from mature adipocytes. Thus, M. alba inhibited lipid accumulation by regulating transcription factors in 3T3-L1 adipocytes without a lipolytic effect. Among the soluble- fractions, the ethyl acetate-soluble fraction had the highest antiadipogenic effects on 3T3-L1 cells. This fraction decreasing intracellular lipid accumulation by 38.5% in response to treatment with 100 microg/mL. In addition, HPLC analysis of the ethyl acetate-soluble fraction of M. alba contained 167.7 microM of protocatechulic acid in 1 mg/mL of fraction, which inhibited lipid accumulation by 44.8% in response to treatment with 100 microM. From these results, M. alba is a possible candidate for regulating lipid accumulation in obesity.

The Phase Relations in the In 2O 3-Al 2ZnO 4-ZnO System at 1350°C

NASA Astrophysics Data System (ADS)

Nakamura, Masaki; Kimizuka, Noboru; Mohri, Takahiko; Isobe, Mitsumasa

1993-08-01

Phase relations in the In 2O 3-Al 2ZnO 4-ZnO system at 1350°C are determined by a classical quenching method. This system consists of In 2O 3, Al 2ZnO 4, ZnO, and homologous phases InAlO 3(ZnO) m ( m = 2, 3, …) having solid solutions with LuFeO 3(ZnO) m-type crystal structures. These solid solution ranges are as follows: In 1+ x1Al 1- x1O 3(ZnO) 2 ( x1 = 0.70)-In 1+ x2Al 1- x2O 3(ZnO) 2 ( x2 = 0.316-0.320), In 2O 3(ZnO) 3-In 1+ xAl 1- xO 3(ZnO) 3 ( x = 0.230), In 2O 3(ZnO) 4-In 1+ xAl 1- xO 3(ZnO) 4 ( x = 0.15-0.16), In 2O 3(ZnO) 5-In 1+ xAl 1- xO 3(ZnO) 5 ( x = 0.116-0.130), In 2O 3(ZnO) 6-In 1+ xAl 1- xO 3(ZnO) 6 ( x = 0.000-0.111), In 2O 3(ZnO) 7-In 1+ xAl 1- xO 3(ZnO) 7 ( x = 0.08), In 2O 3(ZnO) 8-In 1+ xAl 1- xO 3(ZnO) 8 ( x: undetermined), and In 2O 3(ZnO) m-InAlO 3(ZnO) m ( m = 9, 10, 11, 13, 15, 17, and 19). The space groups of these homologous phases belong to R3¯ m for m = odd or P6 3/ mmc for m = even. Their crystal structures, In 1+ xAl 1- xO 3(ZnO) m (0 < x < 1), consist of three kinds of layers: an InO 1.5 layer, an (In xAl 1- xZn)O 2.5 layer, and ZnO layers. A comparison of the phase relations in the In 2O 3- M2ZnO 4-ZnO systems ( M = Fe, Ga, or Al) is made and their characteristic features are discussed in terms of the ionic radii and site preferences of the M cations.

Computational Insights into the Interactions between Calmodulin and the c/nSH2 Domains of p85α Regulatory Subunit of PI3Kα: Implication for PI3Kα Activation by Calmodulin.

PubMed

Ni, Duan; Liu, Dingyu; Zhang, Jian; Lu, Shaoyong

2018-01-04

Calmodulin (CaM) and phosphatidylinositide-3 kinase (PI3Kα) are well known for their multiple roles in a series of intracellular signaling pathways and in the progression of several human cancers. Crosstalk between CaM and PI3Kα has been an area of intensive research. Recent experiments have shown that in adenocarcinoma, K-Ras4B is involved in the CaM-PI3Kα crosstalk. Based on experimental results, we have recently put forward a hypothesis that the coordination of CaM and PI3Kα with K-Ras4B forms a CaM-PI3Kα-K-Ras4B ternary complex, which leads to the formation of pancreatic ductal adenocarcinoma. However, the mechanism for the CaM-PI3Kα crosstalk is unresolved. Based on molecular modeling and molecular dynamics simulations, here we explored the potential interactions between CaM and the c/nSH2 domains of p85α subunit of PI3Kα. We demonstrated that CaM can interact with the c/nSH2 domains and the interaction details were unraveled. Moreover, the possible modes for the CaM-cSH2 and CaM-nSH2 interactions were uncovered and we used them to construct a complete CaM-PI3Kα complex model. The structural model of CaM-PI3Kα interaction not only offers a support for our previous ternary complex hypothesis, but also is useful for drug design targeted at CaM-PI3Kα protein-protein interactions.

[Characteristics of volatile organic compounds (VOCs) emission from electronic products processing and manufacturing factory].

PubMed

Cui, Ru; Ma, Yong-Liang

2013-12-01

Based on the EPA method T0-11 and 14/15 for measurement of toxic organics in air samples, fast VOCs detector, Summa canister and DNPH absorbent were used to determine the VOCs concentrations and the compositions in the ambient air of the workshops for different processes as well as the emission concentration in the exhaust gas. In all processes that involved VOCs release, concentrations of total VOCs in the workshops were 0.1-0.5 mg x m(-3), 1.5-2.5 mg x m(-3) and 20-200 mg x m(-3) for casting, cutting and painting respectively. Main compositions of VOCs in those workshops were alkanes, eneynes, aromatics, ketones, esters and ethers, totally over 20 different species. The main compositions in painting workshop were aromatics and ketones, among which the concentration of benzene was 0.02-0.34 mg x m(-3), toluene was 0.24-3.35 mg x m(-3), ethyl benzene was 0.04-1.33 mg x m(-3), p-xylene was 0.13-0.96 mg x m(-3), m-xylene was 0.02-1.18 mg x m(-3), acetone was 0.29-15.77 mg x m(-3), 2-butanone was 0.06-22.88 mg x m(-3), cyclohexene was 0.02-25.79 mg x m(-3), and methyl isobutyl ketone was 0-21.29 mg x m(-3). The VOCs emission from painting process was about 14 t x a(-1) for one single manufacturing line, and 840 t x a(-1) for the whole factory. According to the work flows and product processes, the solvent used during painting process was the main source of VOCs emission, and the exhaust gas was the main emission point.

Development and Pharmacological Evaluation of New Bone-Targeted (99m)Tc-Radiolabeled Bisphosphonates.

PubMed

Makris, George; Tseligka, Eirini D; Pirmettis, Ioannis; Papadopoulos, Minas S; Vizirianakis, Ioannis S; Papagiannopoulou, Dionysia

2016-07-05

A novel bisphosphonate, 1-(3-aminopropylamino)ethane-1,1-diyldiphosphonic acid (3), was coupled to the tridentate chelators di-2-picolylamine, 2-picolylamine-N-acetic acid, iminodiacetic acid, 3-((2-aminoethyl)thio)-3-(1H-imidazol-4-yl)propanoic acid, and 2-((2-carboxyethyl)thio)-3-(1H-imidazol-4-yl)propanoic acid to form ligands 6, 9, 11, 15, and 19, respectively. Organometallic complexes of the general formula [Re/(99m)Tc(CO)3(κ(3)-L)] were synthesized, where L denotes ligand 6, 9, 11, 15, or 19. The rhenium complexes were prepared at the macroscopic level and characterized by spectroscopic methods. The technetium-99m organometallic complexes were synthesized in high yield and were identified by comparative reversed-phase HPLC with their Re analogues. The (99m)Tc tracers were stable in vitro and exhibited binding to hydroxyapatite. In biodistribution studies, all of the (99m)Tc complexes exhibited high bone uptake superior to that of 25, which is the directly (99m)Tc-labeled bisphosphonate 3, and comparable to that of (99m)Tc-methylene diphosphonate ((99m)Tc-MDP). The tracers [(99m)Tc(CO)3(6)] (26), [(99m)Tc(CO)3(9)] (27), [(99m)Tc(CO)3(11)] (28), and [(99m)Tc(CO)3(15)] (29) exhibited higher bone/blood ratios than (99m)Tc-MDP. 26 had the highest bone uptake at 1 h p.i. The new bisphosphonates showed no substantial growth inhibitory capacity in PC-3, Saos-2, and MCF-7 established cancer cell lines at low concentrations. Incubation of 26 with the same cancer cell lines indicated a rapid and saturated uptake. The promising properties of 26-29 indicate their potential for use as bone-imaging agents.

Brand Cigarillos: Low Price but High Particulate Matter Levels-Is Their Favorable Taxation in the European Union Justified?

PubMed

Wasel, Julia; Boll, Michael; Schulze, Michaela; Mueller, Daniel; Bundschuh, Matthias; Groneberg, David A; Gerber, Alexander

2015-08-06

Second hand smoke (ETS)-associated particulate matter (PM) contributes considerably to indoor air contamination and constitutes a health risk for passive smokers. Easy to measure, PM is a useful parameter to estimate the dosage of ETS that passive smokers are exposed to. Apart from its suitability as a surrogate parameter for ETS-exposure, PM itself affects human morbidity and mortality in a dose-dependent manner. We think that ETS-associated PM should be considered an independent hazard factor, separately from the many other known harmful compounds of ETS. We believe that brand-specific and tobacco-product-specific differences in the release of PM matter and that these differences are of public interest. To generate ETS of cigarettes and cigarillos as standardized and reproducible as possible, an automatic second hand smoke emitter (AETSE) was developed and placed in a glass chamber. L&M cigarettes ("without additives", "red label", "blue label"), L&M filtered cigarillos ("red") and 3R4F standard research cigarettes (as reference) were smoked automatically according to a self-developed, standardized protocol until the tobacco product was smoked down to 8 mm distance from the tipping paper of the filter. Mean concentration (Cmean) and area under the curve (AUC) in a plot of PM2.5 against time were measured, and compared. CmeanPM2.5 were found to be 518 μg/m(3) for 3R4F cigarettes, 576 μg/m(3) for L&M "without additives" ("red"), 448 μg/m(3) for L&M "blue label", 547 μg/m(3) for L&M "red label", and 755 μg/m(3) for L&M filtered cigarillos ("red"). AUCPM2.5-values were 208,214 μg/m(3)·s for 3R4F reference cigarettes, 204,629 μg/m(3)·s for L&M "without additives" ("red"), 152,718 μg/m(3)·s for L&M "blue label", 238,098 μg/m(3)·s for L&M "red label" and 796,909 μg/m(3)·s for L&M filtered cigarillos ("red"). Considering the large and significant differences in particulate matter emissions between cigarettes and cigarillos, we think that a favorable taxation of cigarillos is not justifiable.

In vitro metabolism of alectinib, a novel potent ALK inhibitor, in human: contribution of CYP3A enzymes.

PubMed

Nakagawa, Toshito; Fowler, Stephen; Takanashi, Kenji; Youdim, Kuresh; Yamauchi, Tsuyoshi; Kawashima, Kosuke; Sato-Nakai, Mika; Yu, Li; Ishigai, Masaki

2018-06-01

1. The in vitro metabolism of alectinib, a potent and highly selective oral anaplastic lymphoma kinase inhibitor, was investigated. 2. The main metabolite (M4) in primary human hepatocytes was identified, which is produced by deethylation at the morpholine ring. Three minor metabolites (M6, M1a, and M1b) were also identified, and a minor peak of hydroxylated alectinib (M5) was detected as a possible precursor of M4, M1a, and M1b. 3. M4, an important active major metabolite, was produced and further metabolized to M6 by CYP3A, indicating that CYP3A enzymes were the principal contributors to this route. M5 is possibly produced by CYP3A and other isoforms as the primary step in metabolism, followed by oxidation to M4 mainly by CYP3A. Alternatively, M5 could be oxidized to M1a and M1b via an NAD-dependent process. None of the non-CYP3A-mediated metabolism appeared to be major. 4. In conclusion, this study suggests that involvement of multiple enzymes in the metabolism of alectinib reduces its potential for drug-drug interactions.

Early detection of rheumatoid arthritis in rats and humans with 99mTc-3PRGD2 scintigraphy: imaging synovial neoangiogenesis

PubMed Central

Wang, Xiangcheng; Zhao, Zhenfang; Wang, Tao; Wang, Xuemei; Li, Xiao-Feng

2017-01-01

Objectives: To validate 99mTc-labeled arginylglycylaspartic acid (99mTc-3PRGD2) scintigraphy as a means to image synovial neoangiogenesis in joints afflicted by rheumatoid arthritis and to investigate its potential in the early detection and management of rheumatoid arthritis. Methods: Rheumatoid arthritis and osteoarthritis were generated in Sprague Dawley rats by type II collagen immunization and papain injection, respectively. Rats were imaged with 99mTc-3PRGD2 and 99mTc- methyl diphosphonate (99mTc MDP). X-ray images were also obtained and assessed by a radiologist. Immunohistochemistry of αvβ3 and CD31confirmed the onset of synovial neoangiogenesis. The effect of bevacizumab on rheumatoid arthritis was followed with 99mTc-3PRGD2 scintigraphy. A patient with rheumatoid arthritis and a healthy volunteer were scanned with 99mTc-3PRGD2. Results: Two weeks after immunization, a significant increase in 99mTc-3PRGD2 was observed in the joints of the rheumatoid arthritis model though uptake in osteoarthritis model and untreated controls was low. 99mTc-MDP whole body scans failed to distinguish early rheumatoid arthritis joints from healthy controls. The expression of αvβ3 and CD31was significantly higher in the joints of rheumatoid arthritis rats compared to normal controls. In serial 99mTc-3PRGD2 scintigraphy studies, 99mTc-3PRGD2 uptake increased in parallel with disease progression. Bevacizumab anti-angiogenetic therapy both improved the symptoms of the rheumatoid arthritis rats and significantly decreased 99mTc-3PRGD2 uptake. Significantly higher 99mTc-3PRGD2 accumulation was also observed in rheumatoid arthritis joints in the patient. Conclusions: Our findings indicate that 99mTc-3PRGD2 scintigraphy could detect early rheumatoid arthritis by imaging the associated synovial neoangiogenesis, and may be useful in disease management. PMID:27992368

Early detection of rheumatoid arthritis in rats and humans with 99mTc-3PRGD2 scintigraphy: imaging synovial neoangiogenesis.

PubMed

Wu, Yu; Zhang, Guojian; Wang, Xiangcheng; Zhao, Zhenfang; Wang, Tao; Wang, Xuemei; Li, Xiao-Feng

2017-01-24

To validate 99mTc-labeled arginylglycylaspartic acid (99mTc-3PRGD2) scintigraphy as a means to image synovial neoangiogenesis in joints afflicted by rheumatoid arthritis and to investigate its potential in the early detection and management of rheumatoid arthritis. Rheumatoid arthritis and osteoarthritis were generated in Sprague Dawley rats by type II collagen immunization and papain injection, respectively. Rats were imaged with 99mTc-3PRGD2 and 99mTc- methyl diphosphonate (99mTc MDP). X-ray images were also obtained and assessed by a radiologist. Immunohistochemistry of αvβ3 and CD31confirmed the onset of synovial neoangiogenesis. The effect of bevacizumab on rheumatoid arthritis was followed with 99mTc-3PRGD2 scintigraphy. A patient with rheumatoid arthritis and a healthy volunteer were scanned with 99mTc-3PRGD2. Two weeks after immunization, a significant increase in 99mTc-3PRGD2 was observed in the joints of the rheumatoid arthritis model though uptake in osteoarthritis model and untreated controls was low. 99mTc-MDP whole body scans failed to distinguish early rheumatoid arthritis joints from healthy controls. The expression of αvβ3 and CD31was significantly higher in the joints of rheumatoid arthritis rats compared to normal controls. In serial 99mTc-3PRGD2 scintigraphy studies, 99mTc-3PRGD2 uptake increased in parallel with disease progression. Bevacizumab anti-angiogenetic therapy both improved the symptoms of the rheumatoid arthritis rats and significantly decreased 99mTc-3PRGD2 uptake. Significantly higher 99mTc-3PRGD2 accumulation was also observed in rheumatoid arthritis joints in the patient. Our findings indicate that 99mTc-3PRGD2 scintigraphy could detect early rheumatoid arthritis by imaging the associated synovial neoangiogenesis, and may be useful in disease management.

Maintaining glycogen synthase kinase-3 activity is critical for mTOR kinase inhibitors to inhibit cancer cell growth

PubMed Central

Koo, Junghui; Yue, Ping; Gal, Anthony A.; Khuri, Fadlo R.; Sun, Shi-Yong

2014-01-01

mTOR kinase inhibitors which target both mTORC1 and mTORC2 are being evaluated in cancer clinical trials. Here we report that glycogen synthase kinase-3 (GSK3) is a critical determinant for the therapeutic response to this class of experimental drugs. Pharmacological inhibition of GSK3 antagonized their suppressive effects on the growth of cancer cells similarly to genetic attenuation of GSK3. Conversely, expression of a constitutively activated form of GSK3β sensitized cancer cells to mTOR inhibition. Consistent with these findings, higher basal levels of GSK3 activity in a panel of human lung cancer cell lines correlated with more efficacious responses. Mechanistic investigations showed that mTOR kinase inhibitors reduced cyclin D1 levels in a GSK3β-dependent manner, independent of their effects on suppressing mTORC1 signaling and cap binding. Notably, selective inhibition of mTORC2 triggered proteasome-mediated cyclin D1 degradation, suggesting that mTORC2 blockade is responsible for GSK3-dependent reduction of cyclin D1. Silencing expression of the ubiquitin E3 ligase FBX4 rescued this reduction, implicating FBX4 in mediating this effect of mTOR inhibition. Together, our findings define a novel mechanism by which mTORC2 promotes cell growth, with potential implications for understanding the clinical action of mTOR kinase inhibitors. PMID:24626091

Maintaining glycogen synthase kinase-3 activity is critical for mTOR kinase inhibitors to inhibit cancer cell growth.

PubMed

Koo, Junghui; Yue, Ping; Gal, Anthony A; Khuri, Fadlo R; Sun, Shi-Yong

2014-05-01

mTOR kinase inhibitors that target both mTORC1 and mTORC2 are being evaluated in cancer clinical trials. Here, we report that glycogen synthase kinase-3 (GSK3) is a critical determinant for the therapeutic response to this class of experimental drugs. Pharmacologic inhibition of GSK3 antagonized their suppressive effects on the growth of cancer cells similarly to genetic attenuation of GSK3. Conversely, expression of a constitutively activated form of GSK3β sensitized cancer cells to mTOR inhibition. Consistent with these findings, higher basal levels of GSK3 activity in a panel of human lung cancer cell lines correlated with more efficacious responses. Mechanistic investigations showed that mTOR kinase inhibitors reduced cyclin D1 levels in a GSK3β-dependent manner, independent of their effects on suppressing mTORC1 signaling and cap binding. Notably, selective inhibition of mTORC2 triggered proteasome-mediated cyclin D1 degradation, suggesting that mTORC2 blockade is responsible for GSK3-dependent reduction of cyclin D1. Silencing expression of the ubiquitin E3 ligase FBX4 rescued this reduction, implicating FBX4 in mediating this effect of mTOR inhibition. Together, our findings define a novel mechanism by which mTORC2 promotes cell growth, with potential implications for understanding the clinical action of mTOR kinase inhibitors. ©2014 AACR.

mRNA–mRNA duplexes that auto-elicit Staufen1-mediated mRNA decay

PubMed Central

Gong, Chenguang; Tang, Yalan; Maquat, Lynne E.

2013-01-01

We report a new mechanism by which human mRNAs crosstalk: an Alu element in the 3'-untranslated region (3' UTR) of one mRNA can base-pair with a partially complementary Alu element in the 3' UTR of a different mRNA thereby creating a Staufen1 (STAU1)-binding site (SBS). STAU1 binding to a 3' UTR SBS was previously shown to trigger STAU1-mediated mRNA decay (SMD) by directly recruiting the ATP-dependent RNA helicase UPF1, which is also a key factor in the mechanistically related nonsense-mediated mRNA decay (NMD) pathway. In the case of a 3' UTR SBS created via mRNA–mRNA base-pairing, we show that SMD targets both mRNAs in the duplex provided that both mRNAs are translated. If only one mRNA is translated, then it alone is targeted for SMD. We demonstrate the importance of mRNA–mRNA-triggered SMD to the processes of cell migration and invasion. PMID:24056942

The partition dimension of cycle books graph

NASA Astrophysics Data System (ADS)

Santoso, Jaya; Darmaji

2018-03-01

Let G be a nontrivial and connected graph with vertex set V(G), edge set E(G) and S ⊆ V(G) with v ∈ V(G), the distance between v and S is d(v,S) = min{d(v,x)|x ∈ S}. For an ordered partition ∏ = {S 1, S 2, S 3,…, Sk } of V(G), the representation of v with respect to ∏ is defined by r(v|∏) = (d(v, S 1), d(v, S 2),…, d(v, Sk )). The partition ∏ is called a resolving partition of G if all representations of vertices are distinct. The partition dimension pd(G) is the smallest integer k such that G has a resolving partition set with k members. In this research, we will determine the partition dimension of Cycle Books {B}{Cr,m}. Cycle books graph {B}{Cr,m} is a graph consisting of m copies cycle Cr with the common path P 2. It is shown that the partition dimension of cycle books graph, pd({B}{C3,m}) is 3 for m = 2, 3, and m for m ≥ 4. pd({B}{C4,m}) is 3 + 2k for m = 3k + 2, 4 + 2(k ‑ 1) for m = 3k + 1, and 3 + 2(k ‑ 1) for m = 3k. pd({B}{C5,m}) is m + 1.

Specific requirement of the chromatin modifier mSin3B in cell cycle exit and cellular differentiation

PubMed Central

David, Gregory; Grandinetti, Kathryn B.; Finnerty, Patricia M.; Simpson, Natalie; Chu, Gerald C.; DePinho, Ronald A.

2008-01-01

The Sin3-histone deacetylase (HDAC) corepressor complex is conserved from yeast to humans. Mammals possess two highly related Sin3 proteins, mSin3A and mSin3B, which serve as scaffolds tethering HDAC enzymatic activity, and numerous sequence-specific transcription factors to enable local chromatin regulation at specific gene targets. Despite broad overlapping expression of mSin3A and mSin3B, mSin3A is cell-essential and vital for early embryonic development. Here, genetic disruption of mSin3B reveals a very different phenotype characterized by the survival of cultured cells and lethality at late stages of embryonic development with defective differentiation of multiple lineages—phenotypes that are strikingly reminiscent of those associated with loss of retinoblastoma family members or E2F transcriptional repressors. Additionally, we observe that, whereas mSin3B−/− cells cycle normally under standard growth conditions, they show an impaired ability to exit the cell cycle with limiting growth factors. Correspondingly, mSin3B interacts physically with the promoters of known E2F target genes, and its deficiency is associated with derepression of these gene targets in vivo. Together, these results reveal a critical role for mSin3B in the control of cell cycle exit and terminal differentiation in mammals and establish contrasting roles for the mSin3 proteins in the growth and development of specific lineages. PMID:18332431

Susceptibility of northern corn rootworm Diabrotica barberi (Coleoptera: Chrysomelidae) to mCry3A and eCry3.1Ab Bacillus thuringiensis proteins.

PubMed

Oyediran, Isaac O; Matthews, Phillip; Palekar, Narendra; French, Wade; Conville, Jared; Burd, Tony

2016-12-01

The susceptibility of the northern corn rootworm Diabrotica barberi (Smith & Lawrence) to mCry3A and eCry3.1Ab proteins derived from Bacillus thuringiensis (Bt) was determined using a diet bioassay. Northern corn rootworm neonates were exposed to different concentrations of mCry3A and eCry3.1Ab, incorporated into artificial diet. Larval mortality was evaluated after 7 d. The mCry3A and eCry3.1Ab proteins were found to be toxic to the northern corn rootworm larvae. The LC 50 and LC 99 values for mCry3A were 5.13 and 2482.31 μg/mL, respectively. For eCry3.1Ab, the LC 50 and LC 99 values were 0.49 and 213.01 μg/mL. Based on the estimated lethal concentrations, eCry3.1Ab protein was more efficacious to northern corn rootworm larvae than mCry3A. These lethal concentration values will be used as diagnostic doses for routine annual monitoring for change in susceptibility of field collected northern corn rootworm to mCry3A, and eCry3.1Ab toxins. © 2015 Institute of Zoology, Chinese Academy of Sciences.

[Re-analysis of occupational hazards in foundry].

PubMed

Zhang, Min; Qi, Cheng; Chen, Wei-Hong; Lu, Yang; Du, Xie-Yi; Li, Wen-Jie; Meng, Chuan-San

2010-04-01

To analyze systematically the characteristics of occupational hazards in the foundry, and provide precise data for epidemiology studies and control of occupational hazards in the foundry. Data of airborne dust, chemical occupational hazards and physical occupational agents in environment in the foundry from 1978 to 2008 were dynamically collected. Mean concentration and intensity (geometric mean) of occupational hazards were calculated by job in different years. Main occupational hazards in the foundry were silica, metal fume, noise and heat stress. Silica existed in all of main jobs. The mean concentration of silica before 1986 was an extremely high level of 8.6 mg/m(3), and then remarkably dropped after 1986, with the level of 2.4 mg/m(3) from 1986 to 1989, 2.7 mg/m(3) from 1990 to 2002 and 2.7 mg/m(3) from 2003 to 2008. The trend of silica concentrations by job was consistent with that in general. Silica concentrations among jobs were significantly different, with highest level in melting (4.4 mg/m(3)), followed by cast shakeout and finishing (3.4 mg/m(3)), pouring (3.4 mg/m(3)), sand preparation (2.4 mg/m(3)), moulding (2.1 mg/m(3)) and core-making (1.7 mg/m(3)). Concentration of respirable dust in pouring was highest (2.76 mg/m(3)), followed by cast shakeout and finishing (1.14 mg/m(3)). Mean concentration of asbestos dust in melting was a relative high level of 2.0 mg/m(3). In core-making and sand preparation, there existed emission production of adhesive, with mean concentrations as followed, ammonia (5.84 mg/m(3)), formaldehyde (0.60 mg/m(3)), phenol (1.73 mg/m(3)) and phenol formaldehyde resin (1.3 mg/m(3)) also existed. Benzene and its homologues existed in cast shakeout and finishing, and the level of benzene, toluene, xylene was 0.2 mg/m(3), 0.1 mg/m(3) and 1.3 mg/m(3), respectively. In pouring and melting, there existed chemical occupational hazards, including benzo(a) pyrene, metal fume (lead, cadmium, manganese, nickel, chromium) and gas(hydrogen sulfide, phosphine, sulfur dioxide, carbon monoxide). Mean concentration of benzo(a) pyrene was a low level of 1.80 x 10(-4) microg/m(3). Physical occupational agents in the foundry were noise, heat stress and vibration. Intensity of heat stress was high in melting, pouring and cast shakeout and finishing, with the level of 30 degrees C, 29 degrees C and 26 degrees C, respectively. Noise was high in cast shakeout and finishing and core-making, with the level of 93.1 dB(A) and 89.5 dB(A), respectively. Vibration existed in core-making and cast shakeout and finishing. Compulsory postures included long standing, seating and bowing. Occupational hazards in environment of the foundry are diversified and their concentrations exceed permissible exposure limits stipulated by the national occupational hygienic standards. High-concentrations of dust, metal fume, low-concentrations of variety of chemicals, high-intensity of noise and vibration, heat stress, and harmful compulsory posture, and so on all co-exist in the foundry. Control and protective measures should be strengthened.

Nitrate reduction by zerovalent iron: effects of formate, oxalate, citrate, chloride, sulfate, borate, and phosphate.

PubMed

Su, Chunming; Puls, Robert W

2004-05-01

Recent studies have shown that zerovalent iron (Fe0) may potentially be used as a chemical medium in permeable reactive barriers (PRBs) for groundwater nitrate remediation; however, the effects of commonly found organic and inorganic ligands in soil and sediments on nitrate reduction by Fe0 have not been well understood. A 25.0 mL nitrate solution of 20.0 mg of N L(-1) (1.43 mM nitrate) was reacted with 1.00 g of Peerless Fe0 at 200 rpm on a rotational shaker at 23 degrees C for up to 120 h in the presence of each of the organic acids (3.0 mM formic, 1.5 mM oxalic, and 1.0 mM citric acids) and inorganic acids (3.0 mM HCl, 1.5 mM H2SO4, 3.0 mM H3BO3, and 1.5 mM H3PO4). These acids provided an initial dissociable H+ concentration of 3.0 mM available for nitrate reduction reactions under conditions of final pH < 9.3. Nitrate reduction rates (pseudo-first-order) increased in the order: H3PO4 < citric acid < H3BO3 < oxalic acid < H2SO4 < formic acid < HCl, ranging from 0.00278 to 0.0913 h(-1), corresponding to surface area normalized rates ranging from 0.126 to 4.15 h(-1) m(-2) mL. Correlation analysis showed a negative linear relationship between the nitrate reduction rates for the ligands and the conditional stability constants for the soluble complexes of the ligands with Fe2+ (R2 = 0.701) or Fe3+ (R2 = 0.918) ions. This sequence of reactivity corresponds also to surface adsorption and complexation of the three organic ligands to iron oxides, which increase in the order formate < oxalate < citrate. The results are also consistent with the sequence of strength of surface complexation of the inorganic ligands to iron oxides, which increases in the order: chloride < sulfate < borate < phosphate. The blockage of reactive sites on the surface of Fe0 and its corrosion products by specific adsorption of the inner-sphere complex forming ligands (oxalate, citrate, sulfate, borate, and phosphate) may be responsible for the decreased nitrate reduction by Fe0 relative to the chloride system.

Calcitonin gene-related peptide (CGRP) in the circular muscle of guinea-pig colon: role as inhibitory transmitter and mechanisms of relaxation.

PubMed

Maggi, C A; Giuliani, S; Zagorodnyuk, V

1996-01-16

In the presence of 1 microM tetrodotoxin (TTX), human alpha calcitonin gene-related peptide (CGRP) produced a concentration-dependent relaxation (EC50 1.1 nM; Emax 86% of the relaxation to 1 microM isoprenaline) of mucosa-free circular muscle strips from the guinea-pig proximal colon. In the presence of TTX, the C-terminal fragment CGRP(8-37) produced a concentration (0.3-3 microM)-dependent rightward shift of the curve to CGRP. The TTX-resistant, receptor-mediated, CGRP-induced relaxation was unaffected by apamin (0.3 microM) and L-nitroarginine (L-NOARG, 100 microM), alone or in combination, as well as by glibenclamide (3 microM) or (S)-ketoprofen (10 microM). Tetraethylammonium (TEA, 1-10 mM) and cyclopiazonic acid (CPA, 3-10 microM) produced a concentration-dependent partial inhibition of the relaxant response to CGRP. The inhibitory effect of TEA on the maximal relaxation produced by CGRP was prevented by nifedipine (1 microM) which did not affect the CGRP-relaxation of its own. In the presence of atropine (1 microM), guanethidine (3 microM), SR 140,333 (0.3 microM), MEN 10,627 (1 microM), apamin (0.3 microM) and L-NOARG (100 microM), the application of 1 microM capsaicin produced a transient relaxation of the strips. This response was not reproduced upon a second application of capsaicin, 60 min later, indicating complete desensitization. CGRP(8-37) (0.3-1.0 microM) produced a partial inhibitory effect (about 50% inhibition) of the relaxant response to capsaicin. In the presence of atropine (1 microM), guanethidine (3 microM), SR 140,333 (0.3 microM), MEN 10,627 (1 microM), apamin (0.3 microM), L-NOARG (100 microM) and after capsaicin in vitro pretreatment (10 microM for 15 min), electrical field stimulation (EFS, 10 Hz for 5 s) produced a transient relaxation which was unchanged by CGRP(8-37) (1 microM) while being abolished by TTX. In sucrose gap, brief superfusion with 0.3 microM CGRP produced a TTX (1 microM)- resistant membrane hyperpolarization and relaxation: the hyperpolarization produced by CGRP was inhibited by about 50% by either TEA (10 mM) or CPA (10 microM), while being unaffected by glibenclamide (3 microM). The combined application of TEA and CPA was not more effective (65% inhibition) in inhibiting the CGRP-induced hyperpolarization than each drug alone. We conclude that CGRP produces a direct relaxation of the circular muscle of the guinea-pig proximal colon by activating receptors sensitive to blockade by CGRP(8-37). Activation of Ca-dependent potassium channels and Ca release/reuptake from internal store(s) appear both to be involved in the action of CGRP. Endogenous CGRP mediates part of the relaxant response evoked by stimulation of capsaicin-sensitive primary afferent nerves in the circular muscle of guinea-pig colon, while it is not involved in the apamin and L-NOARG-resistant nonadrenergic noncholinergic (NANC) relaxation produced by electrical field stimulation of intrinsic inhibitory nerves.

[Effect of lipopolysaccharides from Porphyromonas endodontalis on the expression of macrophage colony stimulating factor in mouse osteoblasts].

PubMed

Yu, Yaqiong; Qiu, Lihong; Guo, Jiajie; Qu, Liu; Xu, Liya; Zhong, Ming

2014-09-01

To investigate the effects of lipopolysaccharides (LPS) extracted from Porphyromonas endodontalis (Pe) on the expression of macrophage colony stimulating factor (M-CSF) mRNA and protein in MC3T3-E1 cells and the role of nucler factor-κB (NF-κB) in the process. MC3T3-E1 cells were treated with different concentrations of Pe-LPS (0-50 mg/L) and 10 mg/L Pe-LPS for different hours (0-24 h). The expression of M-CSF mRNA and protein was detected by reverse transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunoadsordent assay (ELISA). The cells untreated by Pe-LPS served as control. The expression of M- CSF mRNA and protein was also detected in 10 mg/L Pe- LPS treated MC3T3-E1 cells after pretreated with BAY 11-7082 for 1 h, a special NF-κB inhibitor. The groups were divided as follows, control group, BAY group (10 µmol/L BAY 11-7082 treated alone MC3T3-E1 cells), Pe-LPS group (10 mg/L Pe-LPS stimulated MC3T3-E1 cells for 6 h), BAY combine with Pe-LPS group (10 µmol/L BAY 11-7082 pretreated cells for 1 h and 10 mg/L of Pe-LPS stimulated MC3T3-E1 cells for 6 h). The level of M- CSF mRNA and protein increased significantly after treatment with different concentrations of Pe-LPS (0-50 mg/L), which indicated that Pe-LPS induced osteoblasts to express M-CSF mRNA and protein in dose dependent manners. The expression of M-CSF protein increased from (35 ± 2) ng/L (control group) to (170 ± 8) ng/L (50 mg/L group). Maximal induction of M-CSF mRNA expression was found in the MC3T3- E1 cells treated with 10 mg/L Pe-LPS for 6 h. After 6 h, the expression of M-CSF mRNA decreased gradually. The expression of M-CSF protein also increased with the treatment of 10 mg/L Pe-LPS for 10 h [(122 ± 4) ng/L]. After 10 h, the expression of M-CSF protein decreased gradually. The mRNA and proteins of M-CSF decreased significantly after pretreatment with 10 µmol/L BAY 11-7082 for 1 h. There was no significant difference between BAY group and the control. Pe-LPS may induce the expression of M-CSF mRNA and protein in MC3T3-E1 cells through the signaling of NF-κB.

Optimal Orbital Coverage of Theater Operations and Targets

DTIC Science & Technology

2007-03-01

3.18). (3.18) 1.000140612 .016708617cos( ) .000139589cos(2 )r M= − − M The obliquity of the ecliptic (ε ) was determined using equation (3.19...estimated using equation (3.16). UT1357.5277233 35999.05034M T= + o (3.16) The ecliptic longitude ( eclipticλ ) was determined using equation (3.17...1.914666471 sin( ) .019994643sin(2 ) ecliptic M Mλ λ= + + o M (3.17) The magnitude of the position vector to the sun was solved for using equation

Coastal Inlets Research Program

DTIC Science & Technology

2012-01-01

Basin Vce, VDe ,VEe,VFe,Vye ,VOe 0.3 Coastal and Hydraulics Laboratory 4  Conduct R&D to reduce O&M costs at coastal navigation projects  Include...200,000 m3 VOe=1,000,000,000 m3 Offshore Ebb Shoal Channel Flood Shoal Bay Deposition Basin Vce, VDe ,VEe,VFe,Vye ,VOe 0.3 …seamless connecting...m3 VOe=1,000,000,000 m3 Offshore Ebb Shoal Channel Flood Shoal Bay Deposition Basin Vce, VDe ,VEe,VFe,Vye ,VOe 0.3 Existing Data Models and

Novel DNA variations to characterize low molecular weight glutenin Glu-D3 genes and develop STS markers in common wheat.

PubMed

Zhao, X L; Xia, X C; He, Z H; Lei, Z S; Appels, R; Yang, Y; Sun, Q X; Ma, W

2007-02-01

Low-molecular-weight glutenin subunits (LMW-GS) play an important role in bread and noodle processing quality by influencing the viscoelasticity and extensibility of dough. The objectives of this study were to characterize Glu-D3 subunit coding genes and to develop molecular markers for identifying Glu-D3 gene haplotypes. Gene specific primer sets were designed to amplify eight wheat cultivars containing Glu-D3a, b, c, d and e alleles, defined traditionally by protein electrophoretic mobility. Three novel Glu-D3 DNA sequences, designated as GluD3-4, GluD3-5 and GluD3-6, were amplified from the eight wheat cultivars. GluD3-4 showed three allelic variants or haplotypes at the DNA level in the eight cultivars, which were designated as GluD3-41, GluD3-42 and GluD3-43. Compared with GluD3-42, a single nucleotide polymorphism (SNP) was detected for GluD3-43 in the coding region, resulting in a pseudo-gene with a nonsense mutation at the 119th position of deduced peptide, and a 3-bp insertion was found in the coding region of GluD3-41, leading to a glutamine insertion at the 249th position of its deduced protein. The coding regions for GluD3-5 and GluD3-6 showed no allelic variation in the eight cultivars tested, indicating that they were relatively conservative in common wheat. Based on the 12 allelic variants of three Glu-D3 genes identified in this study and three detected previously, seven STS markers were established to amplify the corresponding gene sequences in wheat cultivars containing five Glu-D3 alleles (a, b, c, d and e). The seven primer sets M2F12/M2R12, M2F2/M2R2, M2F3/M2R3, M3F1/M3R1, M3F2/M3R2, M4F1/M4R1 and M4F3/M4R3 were specific to the allelic variants GluD3-21/22, GluD3-22, GluD3-23, GluD3-31, GluD3-32, GluD3-41 and GluD3-43, respectively, which were validated by amplifying 20 Chinese wheat cultivars containing alleles a, b, c and f based on protein electrophoretic mobility. These markers will be useful to identify the Glu-D3 gene haplotypes in wheat breeding programs.

Synovitis biomarkers: ex vivo characterization of three biomarkers for identification of inflammatory osteoarthritis.

PubMed

Kjelgaard-Petersen, Cecilie; Siebuhr, Anne Sofie; Christiansen, Thorbjørn; Ladel, Christoph; Karsdal, Morten; Bay-Jensen, Anne-Christine

2015-01-01

Characterize biomarkers measuring extracellular matrix turnover of inflamed osteoarthritis synovium. Human primary fibroblast-like synoviocytes and synovial membrane explants (SMEs) treated with various cytokines and growth factors were assessed by C1M, C3M, and acMMP3 in the conditioned medium. TNFα significantly increased C1M up to seven-fold (p = 0.0002), C3M up to 24-fold (p = 0.0011), and acMMP3 up to 14-fold (p < 0.0001) in SMEs. IL-1β also significantly increased C1M up to five-fold (p = 0.00094), C3M four-fold (p = 0.007), and acMMP3 18-fold (p < 0.0001) in SMEs. The biomarkers C1M, C3M, and acMMP-3 were synovitis biomarkers ex vivo and provide a translational tool together with the SME model.

Metabotropic glutamate receptor 3 activation is required for long-term depression in medial prefrontal cortex and fear extinction

PubMed Central

Walker, Adam G.; Wenthur, Cody J.; Xiang, Zixiu; Rook, Jerri M.; Emmitte, Kyle A.; Niswender, Colleen M.; Lindsley, Craig W.; Conn, P. Jeffrey

2015-01-01

Clinical studies have revealed that genetic variations in metabotropic glutamate receptor 3 (mGlu3) affect performance on cognitive tasks dependent upon the prefrontal cortex (PFC) and may be linked to psychiatric conditions such as schizophrenia, bipolar disorder, and addiction. We have performed a series of studies aimed at understanding how mGlu3 influences PFC function and cognitive behaviors. In the present study, we found that activation of mGlu3 can induce long-term depression in the mouse medial PFC (mPFC) in vitro. Furthermore, in vivo administration of a selective mGlu3 negative allosteric modulator impaired learning in the mPFC-dependent fear extinction task. The results of these studies implicate mGlu3 as a major regulator of PFC function and cognition. Additionally, potentiators of mGlu3 may be useful in alleviating prefrontal impairments associated with several CNS disorders. PMID:25583490

Influence of refrigeration and formalin on the floatability of Giardia duodenalis cysts.

PubMed

Moitinho, M d; Bertoli, M; Guedes, T A; Ferreira, C S

1999-01-01

Giardia duodenalis cysts obtained from fresh fecal samples, fecal samples kept under refrigeration and fecal samples treated with formalin were studied as to their floatability on sucrose solutions with the following specific gravities: 1,040 kg/m3; 1,050 kg/m3; 1, 060 kg/m3; 1,070 kg/m3; 1,080 kg/m3; 1,090 kg/m3; 1,100 kgm3; 1,150 kg/m3; 1,200 kg/m3; and 1,250 kg/m3, contained within counting-chambers 0.17 mm high. Cysts that floated on and those settled down as sediments were counted, and had their percentages estimated. Sucrose solutions of 1,200 kg/m3 specific gravity (the average specific gravity of diluting liquids employed in floatation techniques) caused to float 77.7%, 78.4% and 6.6% of the G. duodenalis cysts obtained, respectively, from fresh fecal samples, fecal samples kept under refrigeration, and fecal samples treated with formalin. Cysts obtained both from fresh fecal samples and fecal samples kept under refrigeration presented similar results concerning floatability. It was observed, however, that the treatment of feces with formalin diminished the cysts floatability under the various specific gravities studied. This results should influence, the recommendations for transport and storage of fecal samples used for parasitological coproscopy.

Characteristics of Atmospheric Pollution in Handan, China

NASA Astrophysics Data System (ADS)

Zhang, P.; Wang, L.; Zhao, X.; Yang, J.; Wei, Z.; Su, J.; Zhang, F.; Meng, C.

2013-12-01

Handan, located in the southern edge of Hebei province, is one of the cities with worst air pollution in China. Based on the data from our comprehensive air quality monitoring station in Handan from August 2012 to January 2013, a series studies on the characteristics of air pollution in Handan were conducted. The daily mean concentration of PM10 and PM2.5 was 231.5 μg/m3 and 125.8 μg/m3 which exceeded daily National Ambient Air Quality Standard II (NAAQS) of China by 54.3% and 67.7% respectively. The highest daily concentration of them was 863.9 μg/m3 and 643.0 μg/m3, appeared on January 11, 2013, exceeding NAAQS by 475.9% and 757.3% respectively. Mean ratio of PM2.5/PM10 was 0.53. High PM2.5/PM10 ratio frequently occurred in winter, especially January (0.63) and February (0.65). Average daily concentration of SO2, NOx, NO2 and CO was 118 μg/m3, 133 μg/m3, 60.4 μg/m3 and 3210 μg/m3 respectively. The maximum daily average concentration of them was 393 μg/m3, 352 μg/m3, 135 μg/m3, 9660 μg/m3 which was 2.62, 3.52, 2.69, 2.42 times of daily NAAQS. The average concentration of total water soluble ions (TWSI) in PM2.5 from October 13 to December 21, 2012 was 69.57 μg/m3 which accounted for 61.67% of PM2.5. NO3-, SO42-, Cl- and NH4+ were the most important components of water soluble ionic composition in PM2.5.their concentration was 21.20 μg/m3, 16.96 μg/m3,8.43 μg/m3 and 14.81 μg/m3, accounted for 18.8%, 15.03% ,7.47% and 13.13% in PM2.5, respectively. Concentration of NO3- and SO42- had a good correlation (R2 = 0.807). The daily average concentration of OC and EC was 22.17 μg/m3, 6.29 μg/m3, accounted for 19.65%, 5.58% in PM2.5 respectively. The average ratio of OC/EC was 3.44, which shows that there is secondary organic carbon (SOC) in carbonaceous aerosol. Chemical characteristics of PM2.5 in Beijing, Tianjin and Handan were very similar. Most of Daily visibility values (67.4%) were lower than 5 km from August 2012 to January 2013. Daily visibility above 16 km was very scarce in Handan. Mean value of daily visibility was only 4.4×3.5 km in the range of 0.3 to 15.6 km. Average daily value of BC, NO, O3, RH, temperature, pressure was 9.3 μg/m3, 35.7 ppb, 20.6 ppb, 64.4%, 12.1 degree and 1011.2 hPa respectively. During the most polluted period from January 6 to January 31, 2013, mean daily visibility was 0.9 km. Average value of BC, NO, RH, temperature and pressure was 20.4 μg/m3, 98.4 ppb, 89.2%, -1.9 degree and 1015.9 hPa respectively. Visibility showed negative correlation with BC, RH, NO2, PM2.5, NOx, PM10, NO, CO, SO2, pressure and showed positive correlation with O3 and temperature. The most related four parameters with visibility were BC, RH, NO2 and PM2.5. The least related four parameters with visibility were O3, temperature, SO2 and pressure. Empirical model was developed to investigate the complex relationships between visibility, meteorological and pollutant parameters. The modeling result was as following: The model computed visibility had good consistence with the observed values.

Asparagine, valine, and threonine in the third extracellular loop of muscarinic receptor have essential roles in the positive cooperativity of strychnine-like allosteric modulators.

PubMed

Jakubík, J; Krejcí, A; Dolezal, V

2005-05-01

We have investigated allosteric interactions of four closely related strychnine-like substances: Wieland-Gumlich aldehyde (WGA), propargyl Wieland-Gumlich aldehyde, strychnine, and brucine with N-methylscopolamine (NMS) on M(3) subtype of muscarinic receptor genetically modified in the second or the third extracellular loop to corresponding loops of M(2) subtype (M(3)o2 and M(3)o3 chimera). The M(3)o2 chimeric receptor The exhibited no change in either affinity of strychnine, brucine, and WGA or in cooperativity of brucine or WGA, whereas both parameters for propargyl-WGA changed. In contrast, there was a change in affinity of all tested modulators (except for brucine) and in their cooperativity in the M(3)o3 chimera. Directions of affinity changes in both chimeras were always toward values of the donor M(2) subtype, but changes in cooperativity were variable. Compared with the native M(3) receptor, strychnine displayed a slight increase in positive cooperativity and propargyl-WGA a robust decrease in negative cooperativity at M(3)o2 chimera. Similar changes were found in the M(3)o3 chimera. Interestingly, cooperativity of brucine and WGA at the M(3)o3 chimera changed from negative to positive. This is the first evidence of constitution of positive cooperativity of WGA by switching sequences of two parental receptors, both exhibiting negative cooperativity. Gradual replacement of individual amino acids revealed that only three residues (NVT of the o3 loop of the M(2) receptor) are involved in this effect. Data suggest that these amino acids are essential for propagation of a conformation change resulting in positive cooperativity induced by these modulators.

Characteristics of luminal bicarbonate secretion by rat cecum in vitro.

PubMed

Canfield, P

1991-03-01

Under in vitro conditions the rat cecum transported HCO3- from the serosal to an unbuffered solution in contact with the mucosal side [Js----m = 7.12 +/- 0.18 mumol.cm-2.h-1 (n = 149)]. With reversed tissues, a significantly lower flux was obtained [Jm----s = 2.47 +/- 0.11 mumol.cm-2.h-1 (n = 42)]. Both fluxes were stable for several hours. Increasing the H+ gradient across the tissue for 60 min did not change either flux. Anoxia for 45 min reversibly reduced Js----m by 65 +/- 3% (n = 20) but had no effect on Jm----s. Both fluxes were linearly related to HCO3- concentration on the buffered side, but the slope for Js----m was 3.5 times that for Jm----s. When tissues were initially set up in HEPES buffer rather than HCO3-, Js----m was 0.12 +/- 0.05 mumol.cm-2.h-1 (n = 6), which is not significantly different from zero. Replacement of Na+ by choline reduced Js----m by 40 +/- 3% (n = 11) and ouabain (1 mM) by 24 +/- 3% (n = 5). Replacement of Cl- with isethionate or K+ with Na+ for 60 min did not alter Js----m. Serosal application of DIDS (0.5 mM) reduced Js----m by 24 +/- 6% (n = 6), but SITS (0.5 mM), furosemide (1 mM), acetazolamide (0.1 mM), amiloride (1 mM), and a proton pump inhibitor (Sch 28080, 50 microM) had no effect. Mucosal application of DIDS, furosemide, and amiloride had no effect on Js----m. Serosal tetrodotoxin (1 microM) and indomethacin (28 microM) were also without effect.(ABSTRACT TRUNCATED AT 250 WORDS)

7-methylguanosine diphosphate (m(7)GDP) is not hydrolyzed but strongly bound by decapping scavenger (DcpS) enzymes and potently inhibits their activity.

PubMed

Wypijewska, Anna; Bojarska, Elzbieta; Lukaszewicz, Maciej; Stepinski, Janusz; Jemielity, Jacek; Davis, Richard E; Darzynkiewicz, Edward

2012-10-09

Decapping scavenger (DcpS) enzymes catalyze the cleavage of a residual cap structure following 3' → 5' mRNA decay. Some previous studies suggested that both m(7)GpppG and m(7)GDP were substrates for DcpS hydrolysis. Herein, we show that mononucleoside diphosphates, m(7)GDP (7-methylguanosine diphosphate) and m(3)(2,2,7)GDP (2,2,7-trimethylguanosine diphosphate), resulting from mRNA decapping by the Dcp1/2 complex in the 5' → 3' mRNA decay, are not degraded by recombinant DcpS proteins (human, nematode, and yeast). Furthermore, whereas mononucleoside diphosphates (m(7)GDP and m(3)(2,2,7)GDP) are not hydrolyzed by DcpS, mononucleoside triphosphates (m(7)GTP and m(3)(2,2,7)GTP) are, demonstrating the importance of a triphosphate chain for DcpS hydrolytic activity. m(7)GTP and m(3)(2,2,7)GTP are cleaved at a slower rate than their corresponding dinucleotides (m(7)GpppG and m(3)(2,2,7)GpppG, respectively), indicating an involvement of the second nucleoside for efficient DcpS-mediated digestion. Although DcpS enzymes cannot hydrolyze m(7)GDP, they have a high binding affinity for m(7)GDP and m(7)GDP potently inhibits DcpS hydrolysis of m(7)GpppG, suggesting that m(7)GDP may function as an efficient DcpS inhibitor. Our data have important implications for the regulatory role of m(7)GDP in mRNA metabolic pathways due to its possible interactions with different cap-binding proteins, such as DcpS or eIF4E.

Collision-induced dissociation analysis of negative atmospheric ion adducts in atmospheric pressure corona discharge ionization mass spectrometry.

PubMed

Sekimoto, Kanako; Takayama, Mitsuo

2013-05-01

Collision-induced dissociation (CID) experiments were performed on atmospheric ion adducts [M + R](-) formed between various types of organic compounds M and atmospheric negative ions R(-) [such as O2(-), HCO3(-), COO(-)(COOH), NO2(-), NO3(-), and NO3(-)(HNO3)] in negative-ion mode atmospheric pressure corona discharge ionization (APCDI) mass spectrometry. All of the [M + R](-) adducts were fragmented to form deprotonated analytes [M - H](-) and/or atmospheric ions R(-), whose intensities in the CID spectra were dependent on the proton affinities of the [M - H](-) and R(-) fragments. Precursor ions [M + R](-) for which R(-) have higher proton affinities than [M - H](-) formed [M - H](-) as the dominant product. Furthermore, the CID of the adducts with HCO3(-) and NO3(-)(HNO3) led to other product ions such as [M + HO](-) and NO3(-), respectively. The fragmentation behavior of [M + R](-) for each R(-) observed was independent of analyte type (e.g., whether the analyte was aliphatic or aromatic, or possessed certain functional groups).

Thyroid hormone deiodinases D1, D2, and D3 are expressed in human endothelial dermal microvascular line: effects of thyroid hormones.

PubMed

Sabatino, Laura; Lubrano, Valter; Balzan, Silvana; Kusmic, Claudia; Del Turco, Serena; Iervasi, Giorgio

2015-01-01

Endothelial system acts as a large endocrine organ in the human body; however, little is still known about the regulative role of THs on endothelial cells. Aim of the present study was to investigate the expression of the TH deiodinases (D1, D2, and D3) and TH receptors (TRα1, TRα2, and TRβ1) in an endothelial microvascular cultured cell model (HMEC-1), after stimulation with triiodothyronine (T3, 10-100 nM), thyroxine (T4, 10-100 nM), and reverse T3 (rT3, 1-10 nM). DIO1 was significantly inhibited by T4 at 10 and 100 nM (p < 0.001). rT3 significantly inhibited DIO1 at 1 nM concentration (p < 0.01) and stimulated DIO1 at 10 nM dosage (p < 0.001). T4 and rT3 significantly inhibited DIO2 at all concentrations. DIO3 was induced at 100 nM T3 (p < 0.05) and 100 nM rT3 (p < 0.01), and TRα1 and TRα2 mRNAs were significantly increased after 100 nM T3 treatment (p < 0.05) and decreased after 1 and 10 nM rT3 (p < 0.05). TRβ1 was significantly increased by all THs at different concentrations: 10 nM T3 and 100 nM T3 (p < 0.05), 1 nM rT3 (p < 0.001), and 100 nM T4 (p < 0.01). D1 and D2 protein levels were evaluated, but no significant difference was observed for any hormonal treatment. For the first time, we found that the TH deiodinases and receptors are expressed in endothelial HMEC-1 cells. These findings might be of significant clinical relevance, given the important regulatory role of the endothelium as first barrier to the bloodstream.

Sequential dark and photo fermentation hydrogen production from hydrolyzed corn stover: A pilot test using 11 m3 reactor.

PubMed

Zhang, Quanguo; Zhang, Zhiping; Wang, Yi; Lee, Duu-Jong; Li, Gang; Zhou, Xuehua; Jiang, Danping; Xu, Bo; Lu, Chaoyang; Li, Yameng; Ge, Xumeng

2018-04-01

Pilot tests of sequential dark and photo fermentation H 2 production were for the first time conducted in a 11 m 3 reactor (3 m 3 for dark and 8 m 3 for photo compartments). A combined solar and light-emitting diode illumination system and a thermal controlling system was installed and tested. With dark fermentation unit maintained at pH 4.5 and 35 °C and photo fermentation unit at pH 7.0 and 30 °C, the overall biogas production rate using hydrolyzed corn stover as substrate reached 87.8 ± 3.8 m 3 /d with 68% H 2 content, contributed by dark unit at 7.5 m 3 -H 2 /m 3 -d and by photo unit at 4.7 m 3 /m 3 -d. Large variation was noted for H 2 production rate in different compartments of the tested units, revealing the adverse effects of poor mixing, washout, and other inhomogeneity associated with large reactor operations. Copyright © 2018 Elsevier Ltd. All rights reserved.

Contribution of 2-methyl-3-furanthiol to the cooked meat-like aroma of fermented soy sauce.

PubMed

Meng, Qi; Kitagawa, Riho; Imamura, Miho; Katayama, Hiroshi; Obata, Akio; Sugawara, Etsuko

2017-01-01

The cooked meat-like aroma compound, 2-methyl-3-furanthiol (2M3F), was detected in fermented soy sauce (FSS) by GC-olfactometry and GC-MS. 2M3F was present in FSS at a concentration considerably greater than the perception threshold, and the 2M3F concentration increased with heating temperature. Sensory analysis indicated that with the addition of only 0.2 μg/L of 2M3F to the soy sauce sample, the cooked meat-like aroma is significantly stronger than that of sample without the addition of 2M3F. Hence, 2M3F contributes to the cooked meat-like aroma of FSS, which constitutes the key aroma component of FSS. In addition, 2M3F was generated from the addition of ribose and cysteine in FSS by heating at 120 °C, but it was not detected in a phosphate buffer under the same condition. Furthermore, 2M3F was not detected in acid-hydrolyzed vegetable-protein-mixed soy sauce (ASS) and heated ASS. These results indicated that fermentation by micro-organisms facilitates the generation of 2M3F in FSS.

A positive chemical ionization GC/MS method for the determination of airborne ethylene glycol and propylene glycols in non-occupational environments.

PubMed

Zhu, Jiping; Feng, Yong-Lai; Aikawa, Bio

2004-11-01

An analytical method for ethylene glycol and propylene glycols has been developed for measuring airborne levels of these chemicals in non-occupational environments such as residences and office buildings. The analytes were collected on charcoal tubes, solvent extracted, and analyzed by gas chromatography-mass spectrometry using a positive chemical ionization technique. The method had a method detection limit of 0.07 microg m(-3) for ethylene glycol and 0.03 microg m(-3) for 1,2- and 1,3-propylene glycols, respectively, based on a 1.44 m3 sampling volume. Indoor air samples of several residential homes and other indoor environments have been analyzed. The median concentrations of ethylene glycol and 1,2-propylene glycol in nine residential indoor air samples were 53 microg m(-3) and 13 microg m(-3) respectively with maximum values of 223 microg m(-3) and 25 microg m(-3) detected for ethylene glycol and 1,2-propylene glycol respectively. The concentrations of these two chemicals in one office and two laboratories were at low microg m(-3) levels. The maximum concentration of 1,3-propylene glycol detected in indoor air was 0.1 microg m(-3).

COHORT Cadre Training Evaluation

DTIC Science & Technology

1987-05-11

on an M240 Machinegun 1 2 3 4 5 6 7 13. Load/Unload the 105mm Main Gun on an M1 Tank 1 2 3 4 5 6 7 14. Load/Unload the M250 Grenade Launcher on an MI...Machinegun 1 2 3 4 5 6 7 13. Load/Unload the 105mm Main Gun on an M1 Tank 1 2 3 4 5 6 7 14. Load/Unload the M250 Grenade Launcher on an M1 Tank 1 2 3 4 5 6

Broken S 3L×S 3R flavor symmetry and leptonic CP violation

NASA Astrophysics Data System (ADS)

Si, Zong-guo; Yang, Xing-hua; Zhou, Shun

2017-11-01

In the framework of the canonical seesaw model, we present a simple but viable scenario to explicitly break an S 3L×S 3R flavor symmetry in the leptonic sector. It turns out that the leptonic flavor mixing matrix is completely determined by the mass ratios of the charged leptons (i.e., m e/m μ and m μ/m τ) and those of light neutrinos (i.e., m 1/m 2 and m 2/m 3). The latest global-fit results of the three neutrino mixing angles {θ 12, θ 13, θ 23} and two neutrino mass-squared differences at the 3σ level are used to constrain the parameter space of {m 1/m 2,m 2/m 3}. The predictions for the mass spectrum and flavor mixing are highlighted: (1) the neutrino mass spectrum shows a hierarchical pattern and a normal ordering, e.g., m 1≈2.2 meV, m 2≈8.8 meV and m 3≈52.7 meV (2) only the first octant of θ 23 is allowed, namely, 41.8°≲θ 23≲43.3° (3) the Dirac CP-violating phase δ≈-22° deviates significantly from the maximal value -90°. All these predictions are ready to be tested in ongoing and forthcoming neutrino oscillation experiments. Moreover, we demonstrate that the cosmological matter-antimatter asymmetry can be explained via resonant leptogenesis, including the individual lepton-flavor effects. In our scenario, leptonic CP violation at low- and high-energy scales is closely connected. Supported by NNSFC (11325525), National Recruitment Program for Young Professionals and CAS Center for Excellence in Particle Physics (CCEPP)

Radiological risk assessment of environmental radon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khalid, Norafatin; Majid, Amran Ab; Yahaya, Redzuwan

Measurements of radon gas ({sup 222}Rn) in the environmental are important to assess indoor air quality and to study the potential risk to human health. Generally known that exposure to radon is considered the second leading cause of lung cancer after smoking. The environmental radon concentration depends on the {sup 226}Ra concentration, indoor atmosphere, cracking on rocks and building materials. This study was carried out to determine the indoor radon concentration from selected samples of tin tailings (amang) and building materials in an airtight sealed homemade radon chamber. The radiological risk assessment for radon gas was also calculated based onmore » the annual exposure dose, effective dose equivalent, radon exhalation rates and fatal cancer risk. The continuous radon monitor Sun Nuclear model 1029 was used to measure the radon concentration emanates from selected samples for 96 hours. Five types of tin tailings collected from Kampar, Perak and four samples of building materials commonly used in Malaysia dwellings or building constructions were analysed for radon concentration. The indoor radon concentration determined in ilmenite, monazite, struverite, xenotime and zircon samples varies from 219.6 ± 76.8 Bq m{sup −3} to 571.1 ± 251.4 Bq m{sup −3}, 101.0 ± 41.0 Bq m{sup −3} to 245.3 ± 100.2 Bq m{sup −3}, 53.1 ± 7.5 Bq m{sup −3} to 181.8 ± 9.7 Bq m{sup −3}, 256.1 ± 59.3 Bq m{sup −3} to 652.2 ± 222.2 Bq m{sup −3} and 164.5 ± 75.9 Bq m{sup −3} to 653.3 ± 240.0 Bq m{sup −3}, respectively. Whereas, in the building materials, the radon concentration from cement brick, red-clay brick, gravel aggregate and cement showed 396.3 ± 194.3 Bq m{sup −3}, 192.1 ± 75.4 Bq m{sup −3}, 176.1 ± 85.9 Bq m{sup −3} and 28.4 ± 5.7 Bq m{sup −3}, respectively. The radon concentration in tin tailings and building materials were found to be much higher in xenotime and cement brick samples than others. All samples in tin tailings were exceeded the action level for radon gas of 148 Bq m{sup −3} proposed by EPA except monazite 0.15 kg, struverite 0.15 kg and 0.25 kg. Whereas, all building material samples have exceeded the radon concentration in concrete and building materials of 3 to 7 Bq m{sup −3} estimated by ICRP. The annual effective dose, effective dose equivalent, and radon exhalation rates in tin tailings were calculated to be in the range of 2.47 to 11.46 mSv, 5.94 to 1090.56 mSv y{sup −1}, and 0.23 to 1.18 mBq kg{sup −1} h{sup −1}. For building materials, the calculated risk assessment of the annual effective dose, effective dose equivalent, radon exhalation rates and fatal cancer risk were 0.72 to 10.00 mSv, 1.73 to 24.00 mSv y{sup −1}, 0.010 to 0.06 mBq kg{sup −1} h{sup −1} and 40 to 550 chances of persons will suffer the cancer per million (1 × 10{sup 6}), respectively.« less

Determination of gaseous and particulate carbonyls (glycolaldehyde, hydroxyacetone, glyoxal, methylglyoxal, nonanal and decanal) in the atmosphere at Mt. Tai

NASA Astrophysics Data System (ADS)

Kawamura, K.; Okuzawa, K.; Aggarwal, S. G.; Irie, H.; Kanaya, Y.; Wang, Z.

2013-01-01

Gaseous and particulate semi-volatile carbonyl compounds were determined every three hours in the atmosphere of Mount Tai (elevation, 1534 m) in the North China Plain during 2-5, 23-24 and 25 June, 2006 under a clear sky condition. Using two-step filter cartridge in a series, particulate carbonyls were first collected on a quartz filter and then gaseous carbonyls were collected on a quartz filter impregnated with O-benzylhydroxylamine (BHA). After the two-step derivatization with BHA and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), carbonyl derivatives were measured using a gas chromatography. The gaseous concentrations were obtained as follow: glycolaldehyde (range 0-1271 ng m-3, average 555 ng m-3), hydroxyacetone (0-707 ng m-3, 163 ng m-3), glyoxal (198-1396 ng m-3, 720 ng m-3), methylglyoxal (410-3170 ng m-3, 1376 ng m-3), n-nonanal (0-236 ng m-3, 71 ng m-3), and n-decanal (0-159 ng m-3, 31 ng m-3). These concentrations are among the highest ever reported in the urban and forest atmosphere. We found that gaseous carbonyls are more than 10 times more abundant than particulate carbonyls. Time-resolved variations of carbonyls did not show any a clear diurnal pattern, except for hydroxyacetone. We found that glyoxal, methylglyoxal and glycolaldehyde positively correlated with levoglucosan (a tracer of biomass burning), suggesting that a contribution from field burning of agricultural wastes (wheat crops) is significant for the bifunctional carbonyls in the atmosphere of Mt. Tai. Upward transport of the pollutants to the mountaintop from the low lands in the North China Plain is a major process to control the distributions of carbonyls in the upper atmosphere over Mt. Tai.

DNA methylation analysis in rat kidney epithelial cells exposed to 3-MCPD and glycidol.

PubMed

Senyildiz, Mine; Alpertunga, Buket; Ozden, Sibel

2017-10-01

3-Monochloropropane-1,2-diol (3-MCPD) is a well-known food processing contaminant that has been regarded as a rat carcinogen, which is known to induce Leydig-cell and mammary gland tumors in males, as well as kidney tumors in both genders. 3-MCPD is highly suspected to be a non-genotoxic carcinogen. 2,3-Epoxy-1-propanol (glycidol) can be formed via dehalogenation from 3-MCPD. We aimed to investigate the cytotoxic effects of 3-MCPD and glycidol, then to demonstrate the possible epigenetic mechanisms with global and gene-specific DNA methylation in rat kidney epithelial cells (NRK-52E). IC 50 value of 3-MCPD was determined as 48 mM and 41.39 mM, whereas IC 50 value of glycidol was 1.67 mM and 1.13 mM by MTT and NRU test, respectively. Decreased global DNA methylation at the concentrations of 100 μM and 1000 μM for 3-MCPD and 100 μM and 500 μM for glycidol were observed after 48 h exposure by using 5-methylcytosine (5-mC) ELISA kit. Methylation changes were detected in promoter regions of c-myc and Rassf1a in 3-MCPD and glycidol treated NRK-52E cells by using methylation-specific PCR (MSP), whereas changes on gene expression of c-myc and Rassf1a were observed by using real-time PCR. However, e-cadherin, p16, VHL and p15 genes were unmethylated in their CpG promoter regions in response to treatment with 3-MCPD and glycidol. Alterations in DNA methylation might be key events in the toxicity of 3-MCPD and glycidol.

Immunosuppressive Yersinia Effector YopM Binds DEAD Box Helicase DDX3 to Control Ribosomal S6 Kinase in the Nucleus of Host Cells.

PubMed

Berneking, Laura; Schnapp, Marie; Rumm, Andreas; Trasak, Claudia; Ruckdeschel, Klaus; Alawi, Malik; Grundhoff, Adam; Kikhney, Alexey G; Koch-Nolte, Friedrich; Buck, Friedrich; Perbandt, Markus; Betzel, Christian; Svergun, Dmitri I; Hentschke, Moritz; Aepfelbacher, Martin

2016-06-01

Yersinia outer protein M (YopM) is a crucial immunosuppressive effector of the plaque agent Yersinia pestis and other pathogenic Yersinia species. YopM enters the nucleus of host cells but neither the mechanisms governing its nucleocytoplasmic shuttling nor its intranuclear activities are known. Here we identify the DEAD-box helicase 3 (DDX3) as a novel interaction partner of Y. enterocolitica YopM and present the three-dimensional structure of a YopM:DDX3 complex. Knockdown of DDX3 or inhibition of the exportin chromosomal maintenance 1 (CRM1) increased the nuclear level of YopM suggesting that YopM exploits DDX3 to exit the nucleus via the CRM1 export pathway. Increased nuclear YopM levels caused enhanced phosphorylation of Ribosomal S6 Kinase 1 (RSK1) in the nucleus. In Y. enterocolitica infected primary human macrophages YopM increased the level of Interleukin-10 (IL-10) mRNA and this effect required interaction of YopM with RSK and was enhanced by blocking YopM's nuclear export. We propose that the DDX3/CRM1 mediated nucleocytoplasmic shuttling of YopM determines the extent of phosphorylation of RSK in the nucleus to control transcription of immunosuppressive cytokines.

Inhibition of polyomavirus ori-dependent DNA replication by mSin3B.

PubMed

Xie, An-Yong; Folk, William R

2002-12-01

When tethered in cis to DNA, the transcriptional corepressor mSin3B inhibits polyomavirus (Py) ori-dependent DNA replication in vivo. Histone deacetylases (HDACs) appear not to be involved, since tethering class I and class II HDACs in cis does not inhibit replication and treating the cells with trichostatin A does not specifically relieve inhibition by mSin3B. However, the mSin3B L59P mutation that impairs mSin3B interaction with N-CoR/SMRT abrogates inhibition of replication, suggesting the involvement of N-CoR/SMRT. Py large T antigen interacts with mSin3B, suggesting an HDAC-independent mechanism by which mSin3B inhibits DNA replication.

Monoanionic 99mTc-tricarbonyl-aminopolycarboxylate complexes with uncharged pendant groups: Radiosynthesis and evaluation as potential renal tubular tracers.

PubMed

Lipowska, Malgorzata; Klenc, Jeffrey; Jarkas, Nashwa; Marzilli, Luigi G; Taylor, Andrew T

2017-04-01

99m Tc(CO) 3 -nitrilotriacetic acid, 99m Tc(CO) 3 (NTA), is a new renal tubular agent with pharmacokinetic properties comparable to those of 131 I-OIH but the clearance of 99m Tc(CO) 3 (NTA) and 131 I-OIH is still less than the clearance of PAH, the gold standard for the measurement of effective renal plasma flow. At physiological pH, dianionic 99m Tc(CO) 3 (NTA) has a mononegative inner metal-coordination sphere and a mononegative uncoordinated carboxyl group. To evaluate alternate synthetic approaches, we assessed the importance of an uncoordinated carboxyl group, long considered essential for tubular transport, by evaluating the pharmacokinetics of three analogs with the 99m Tc(CO) 3 (NTA) metal-coordination sphere but with uncharged pendant groups. 99m Tc(CO) 3 complexes with N-(2-acetamido)iminodiacetic acid (ADA), N-(2-hydroxyethyl)iminodiacetic acid (HDA) and N-(fluoroethyl)iminodiacetic acid (FEDA) were prepared using a tricarbonyl kit and isolated by HPLC. The pharmacokinetics were evaluated in Sprague-Dawley rats, with 131 I-OIH as an internal control; urine was analyzed for metabolites. Plasma protein binding and erythrocyte uptake were determined from the 10min blood samples. Re(CO) 3 (FEDA), the analog of 99m Tc(CO) 3 (FEDA), was prepared and characterized. 99m Tc(CO) 3 (ADA), 99m Tc(CO) 3 (HDA) and 99m Tc(CO) 3 (FEDA) were efficiently prepared as a single species with high radiochemical purities (>99%). These new monoanionic 99m Tc(CO) 3 tracers with uncharged dangling groups all showed rapid blood clearance and high specificity for renal excretion. Activity in the urine, as a percent of 131 I-OIH at 10 and 60min, was 96% and 99% for ADA, 96% and 100% for HDA, and 100% and 99% for FEDA, respectively. Each new tracer was excreted unchanged in the urine. The Re(CO) 3 (FEDA) structure adds compelling evidence that such 99m Tc(CO) 3 (NTA) analogs have metal-coordination spheres identical to that of 99m Tc(CO) 3 (NTA). New tracers lacking the negatively charged pendant carboxyl group previously thought to be essential for rapid renal extraction, 99m Tc(CO) 3 (ADA), 99m Tc(CO) 3 (HDA) and 99m Tc(CO) 3 (FEDA), exhibit pharmacokinetics in rats comparable to those of 99m Tc(CO) 3 (NTA) and 131 I-OIH. Furthermore, these encouraging results in rats warrant evaluation of this new tracer type in humans. Copyright © 2016 Elsevier Inc. All rights reserved.

Efficacy and Safety of Paliperidone Palmitate 3-Month Formulation for Patients with Schizophrenia: A Randomized, Multicenter, Double-Blind, Noninferiority Study

PubMed Central

Xu, Haiyan; Gopal, Srihari; Nuamah, Isaac; Ravenstijn, Paulien; Janik, Adam; Schotte, Alain; Hough, David; Fleischhacker, Wolfgang W.

2016-01-01

Background: This double-blind, parallel-group, multicenter, phase-3 study was designed to test the noninferiority of paliperidone palmitate 3-month formulation (PP3M) to the currently marketed 1-month formulation (PP1M) in patients (age 18–70 years) with schizophrenia, previously stabilized on PP1M. Methods: After screening (≤3 weeks) and a 17-week, flexible-dosed, open-label phase (PP1M: day 1 [150mg eq. deltoid], day 8 [100mg eq. deltoid.], weeks 5, 9, and 13 [50, 75, 100, or 150mg eq., deltoid/gluteal]), clinically stable patients were randomized (1:1) to PP3M (fixed-dose, 175, 263, 350, or 525mg eq. deltoid/gluteal) or PP1M (fixed-dose, 50, 75, 100, or 150mg eq. deltoid/gluteal) for a 48-week double-blind phase. Results: Overall, 1016/1429 open-label patients entered the double-blind phase (PP3M: n=504; PP1M: n=512) and 842 completed it (including patients with relapse). PP3M was noninferior to PP1M: relapse rates were similar in both groups (PP3M: n=37, 8%; PP1M: n=45, 9%; difference in relapse-free rate: 1.2% [95% CI:-2.7%; 5.1%]) based on Kaplan-Meier estimates (primary efficacy). Secondary endpoint results (changes from double-blind baseline in positive and negative symptom score total and subscale scores, Clinical Global Impression-Severity, and Personal and Social Performance scores) were consistent with primary endpoint results. No clinically relevant differences were observed in pharmacokinetic exposures between PP3M and PP1M. Both groups had similar tolerability profiles; increased weight was the most common treatment-emergent adverse event (double-blind phase; 21% each). No new safety signals were detected. Conclusion: Taken together, PP3M with its 3-month dosing interval is a unique option for relapse prevention in schizophrenia. PMID:26902950

Two Genetic Determinants Acquired Late in Mus Evolution Regulate the Inclusion of Exon 5, which Alters Mouse APOBEC3 Translation Efficiency

PubMed Central

Li, Jun; Hakata, Yoshiyuki; Takeda, Eri; Liu, Qingping; Iwatani, Yasumasa; Kozak, Christine A.; Miyazawa, Masaaki

2012-01-01

Mouse apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like editing complex 3 (mA3), an intracellular antiviral factor, has 2 allelic variations that are linked with different susceptibilities to beta- and gammaretrovirus infections among various mouse strains. In virus-resistant C57BL/6 (B6) mice, mA3 transcripts are more abundant than those in susceptible BALB/c mice both in the spleen and bone marrow. These strains of mice also express mA3 transcripts with different splicing patterns: B6 mice preferentially express exon 5-deficient (Δ5) mA3 mRNA, while BALB/c mice produce exon 5-containing full-length mA3 mRNA as the major transcript. Although the protein product of the Δ5 mRNA exerts stronger antiretroviral activities than the full-length protein, how exon 5 affects mA3 antiviral activity, as well as the genetic mechanisms regulating exon 5 inclusion into the mA3 transcripts, remains largely uncharacterized. Here we show that mA3 exon 5 is indeed a functional element that influences protein synthesis at a post-transcriptional level. We further employed in vitro splicing assays using genomic DNA clones to identify two critical polymorphisms affecting the inclusion of exon 5 into mA3 transcripts: the number of TCCT repeats upstream of exon 5 and the single nucleotide polymorphism within exon 5 located 12 bases upstream of the exon 5/intron 5 boundary. Distribution of the above polymorphisms among different Mus species indicates that the inclusion of exon 5 into mA3 mRNA is a relatively recent event in the evolution of mice. The widespread geographic distribution of this exon 5-including genetic variant suggests that in some Mus populations the cost of maintaining an effective but mutagenic enzyme may outweigh its antiviral function. PMID:22275865

Melanocortin Antagonist Tetrapeptides with Minimal Agonist Activity at the Mouse Melanocortin-3 Receptor

PubMed Central

2014-01-01

The melanocortin system regulates many important functions in the body. There are five melanocortin G protein-coupled receptor subtypes known to date. Herein, we report a structure–activity relationship (SAR) study of a tetrapeptide lead discovered through a double substitution strategy at the melanocortin core His-Phe-Arg-Trp sequence. Several compounds were identified with micromolar agonist activity at the mouse melanocortin-1 (mMC1R) and mouse melanocortin-5 receptor (mMC5R) subtypes, weak antagonist activity at the mouse melanocortin-3 receptor (mMC3R), and potent antagonist activity at the mouse melanocortin-4 receptor (mMC4R). Two compounds (2 and 3) were nanomolar mMC4R antagonists with no mMC3R antagonist activity observed. Additionally, we identified three tetrapeptide MC3R antagonists (1, 6, and 7) that possess minimal mMC3R agonist activity only at 100 μM, not commonly observed for mMC3R/mMC4R antagonists. These novel molecular templates have the potential as molecular probes to better differentiate the roles of the centrally expressed MC3 and MC4 receptors. PMID:25699138

PNPLA3 is regulated by glucose in human hepatocytes, and its I148M mutant slows down triglyceride hydrolysis.

PubMed

Perttilä, Julia; Huaman-Samanez, Carolina; Caron, Sandrine; Tanhuanpää, Kimmo; Staels, Bart; Yki-Järvinen, Hannele; Olkkonen, Vesa M

2012-05-15

Liver fat is increased in carriers of the minor G allele in rs738409 (I148M amino acid substitution) in patatin-like phospholipase domain-containing 3 (PNPLA3)/adiponutrin. We studied transcriptional regulation of PNPLA3 in immortalized human hepatocytes (IHH) and human hepatoma cells (HuH7) and the impact of PNPLA3 I148M mutant on hepatocyte triglyceride metabolism. Studies in IHH showed that silencing of the carbohydrate response element-binding protein (ChREBP) abolished induction of PNPLA3 mRNA by glucose. Glucose-dependent binding of ChREBP to a newly identified carbohydrate response element in the PNPLA3 promoter was demonstrated by chromatin immunoprecipitation. Adenoviral overexpression of mouse ChREBP in IHH failed to induce PNPLA3 mRNA. [(3)H]acetate or [(3)H]oleate incorporation with 1-h pulse labeling or 18-h [(3)H]oleate labeling in HuH7 cells showed no effect of PNPLA3 I148M on triglyceride (TG) synthesis in the absence of free fatty acid (FFA) loading. Increased [(3)H]oleate accumulation into triglycerides in I148M-expressing cells was observed after 18 h of labeling in the presence of 200 μM FFA-albumin complexes. This was accompanied by increased PNPLA3 protein levels. The rate of hydrolysis of [(3)H]TG during lipid depletion was decreased significantly by PNPLA3 I148M. Our results suggest that PNPLA3 is regulated in human hepatocytes by glucose via ChREBP. PNPLA3 I148M enhances cellular accumulation of [(3)H]TG in the presence of excess FFA, which is known to stabilize PNPLA3 protein. These data do not exclude an effect of PNPLA3 I148M on hepatocyte lipogenesis but show that the mutant increases the stability of triglycerides.

Straight-chain alcohols exhibit a cutoff in potency for the inhibition of recombinant glutamate receptor subunits

PubMed Central

Akinshola, B Emmanuel

2001-01-01

The effects of n-alcohols (methanol to 1-decanol) on kainate-activated AMPA receptor subunit GluR1 and GluR3 ion currents were studied in Xenopus oocytes using the two-electrode voltage-clamp recording technique. For short-chain alcohols from methanol to 1-hexanol, potency for inhibition of GluR1 and GluR3 receptor-mediated current increased in proportion to the chain length or hydrophobicity of the alcohol. The IC50 values of these alcohols for GluR1 were: methanol, 702 mM; ethanol, 170 mM; 1-propanol, 69 mM; 1-butanol, 20 mM; 1-pentanol, 17 mM; and 1-hexanol, 10 mM. For GluR3, IC50 values were: methanol, 712 mM; ethanol, 238 mM; 1-propanol, 50 mM; 1-butanol, 32 mM; 1-pentanol, 13 mM; and 1-hexanol, 7 mM. For long-chain alcohols, 1-heptanol was less potent than 1-hexanol (estimated IC50: 19 mM for GluR1 and 18 mM for GluR3), 1-octanol had little effect only on GluR3, and 1-nonanol and 1-decanol did not significantly inhibit both GluR1 and GluR3 responses. The observations indicate that straight-chain n-alcohols exhibit a cutoff in their potency for inhibition of the function of non-NMDA glutamate receptor subunits, GluR1 and GluR3. The cutoff in potency of n-alcohols for inhibition of non-NMDA glutamate receptor function is consistent with the interpretation that alcohols affect the function of these receptor-channels by interacting with an alcohol binding site of specific dimensions on the receptor protein. PMID:11429388

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, X. J.; Zhong, J. X.; Glaser, R.

The unidentified infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 μm, commonly attributed to polycyclic aromatic hydrocarbon (PAH) molecules, have recently been ascribed to mixed aromatic/aliphatic organic nanoparticles. More recently, an upper limit of <9% was placed on the aliphatic fraction (i.e., the fraction of carbon atoms in aliphatic form) of the UIE carriers based on the observed intensities of the 3.4 μm and 3.3 μm emission features by attributing them to aliphatic and aromatic C-H stretching modes, respectively, and assuming A{sub 3.4}/A{sub 3.3} ≈ 0.68 derived from a small set of aliphatic and aromatic compounds, wheremore » A{sub 3.4} and A{sub 3.3} are, respectively, the band strengths of the 3.4 μm aliphatic and 3.3 μm aromatic C-H bonds. To improve the estimate of the aliphatic fraction of the UIE carriers, here we analyze 35 UIE sources exhibiting both the 3.3 μm and 3.4 μm C-H features and determine I{sub 3.4}/I{sub 3.3}, the ratio of the power emitted from the 3.4 μm feature to that from the 3.3 μm feature. We derive the median ratio to be (I{sub 3.4}/I{sub 3.3}) ≈ 0.12. We employ density functional theory to compute A{sub 3.4}/A{sub 3.3} for a range of methyl-substituted PAHs. The resulting A{sub 3.4}/A{sub 3.3} ratio well exceeds ∼1.4, with an average ratio of A{sub 3.4}/A{sub 3.3} ≈ 1.76. By attributing the 3.4 μm feature exclusively to aliphatic C-H stretch (i.e., neglecting anharmonicity and superhydrogenation), we derive the fraction of C atoms in aliphatic form from I{sub 3.4}/I{sub 3.3} ≈ 0.12 and A{sub 3.4}/A{sub 3.3} ≈ 1.76 to be ∼2%. We therefore conclude that the UIE emitters are predominantly aromatic.« less

Improving brightness and photostability of green and red fluorescent proteins for live cell imaging and FRET reporting.

PubMed

Bajar, Bryce T; Wang, Emily S; Lam, Amy J; Kim, Bongjae B; Jacobs, Conor L; Howe, Elizabeth S; Davidson, Michael W; Lin, Michael Z; Chu, Jun

2016-02-16

Many genetically encoded biosensors use Förster resonance energy transfer (FRET) to dynamically report biomolecular activities. While pairs of cyan and yellow fluorescent proteins (FPs) are most commonly used as FRET partner fluorophores, respectively, green and red FPs offer distinct advantages for FRET, such as greater spectral separation, less phototoxicity, and lower autofluorescence. We previously developed the green-red FRET pair Clover and mRuby2, which improves responsiveness in intramolecular FRET reporters with different designs. Here we report the engineering of brighter and more photostable variants, mClover3 and mRuby3. mClover3 improves photostability by 60% and mRuby3 by 200% over the previous generation of fluorophores. Notably, mRuby3 is also 35% brighter than mRuby2, making it both the brightest and most photostable monomeric red FP yet characterized. Furthermore, we developed a standardized methodology for assessing FP performance in mammalian cells as stand-alone markers and as FRET partners. We found that mClover3 or mRuby3 expression in mammalian cells provides the highest fluorescence signals of all jellyfish GFP or coral RFP derivatives, respectively. Finally, using mClover3 and mRuby3, we engineered an improved version of the CaMKIIα reporter Camuiα with a larger response amplitude.

40 CFR 1066.1005 - Symbols, abbreviations, acronyms, and units of measure.

Code of Federal Regulations, 2014 CFR

2014-07-01

... joule per kelvin J/K J · K−1 C v heat capacity at constant volume joule per kelvin J/K J · K−1 d... m3 Q flow rate cubic feet per minute or cubic meter per second ft3/min or m3/s m3/s r mass density... · s−1 V volume cubic meter m3 m3 VP volume percent x concentration of emission over a test interval...

Occupational exposure to aromatic hydrocarbons and polycyclic aromatic hydrocarbons at a coke plant.

PubMed

Bieniek, Grażyna; Łusiak, Agnieszka

2012-08-01

The objective of this study was to assess the external exposure to aromatic hydrocarbons (AHs) and polycyclic aromatic hydrocarbons (PAHs) of coke-oven workers and by-product workers at a coke plant in Poland. The content of benzene, toluene, xylene, and naphthalene in a gaseous phase and the content of dibenzo[a,h]anthracene, benz[a]anthracene, anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, benz[ghi]perylene, chrysene, and indeno[1,2,3-c,d]pyrene in a particulate phase of coke plant workers were measured in the workers mentioned above. A toxic equivalency factor BaP(eq) was used to estimate human health risk associated with respiratory exposure to PAHs. Time-weighted values of the exposure to AHs in the coke plant were as follows: benzene (range 0.01-2.71 mg m(-3)), toluene (0.01-1.73 mg m(-3)), xylene (0.01-0.78 mg m(-3)), naphthalene (6.0-6079 μg m(-3)), and the concentrations of hydrocarbons did not exceed the exposure limits. The results for particle-bound PAHs were equal to 1.96 μg m(-3) for B(a)P, 0.73 μg m(-3) for DBA, 3.23 μg m(-3) for BaA, 4.35 μg m(-3) for BbF, 3.02 μg m(-3) for BkF, 4.54 μg m(-3) for IND, 4.32 μg m(-3) for CHR, and 0.73 μg m(-3) for Ant. The results of personal air measurements (median values of the sum of nine carcinogenic PAHs) were 2.115 μg m(-3) (coke-oven workers, n = 207), 0.326 μg m(-3) (coke by-product workers, n = 33), and 0.653 μg m(-3) (total area workers, n = 38). The benzo[a]pyrene equivalent concentrations (BaP(eq)) of 10 PAHs were 1.33, 0.183, and 0.284 μg m(-3), respectively. We found out that coke plant workers are simultaneously exposed to a mixture of aromatic and polycyclic hydrocarbons present in the breathing zone air. Exposure levels are significantly influenced by job categories. Coke by-product workers are significantly more exposed to benzene, toluene, and xylene and less to PAHs. Coke-oven workers are mainly exposed to PAHs. Coke-oven workplaces (top side, coke side, and push side) are characterized by higher carcinogenic risk than other coke plant workplaces.

Characterization and source identification of trace elements in airborne particulates at urban and suburban atmospheres of Tabriz, Iran.

PubMed

Gholampour, Akbar; Nabizadeh, Ramin; Hassanvand, Mohammad Sadegh; Taghipour, Hasan; Rafee, Mohammad; Alizadeh, Zahra; Faridi, Sasan; Mahvi, Amir Hossein

2016-01-01

Concentration of particulate matter (PM10 and total suspended particulate (TSP)) and their elemental constituents were measured to identify the major sources of elements in urban and industrial suburban sites in Tabriz, Iran, from September 2012 to June 2013. TSP and PM10 samples were collected using high-volume samplers. Concentrations of 31 elements in aerosols and crustal soil were determined by ICPMS. The most abundant detected metals in the urban sampling sites were Al (217.5-4019.9 ng m(-3)), Fe (272.5-7658.0 ng m(-3)), Pt (4.7-1994.4 ng m(-3)), and P (13.6-2054.8 ng m(-3) (for TSP and Al (217.6-3687.3 ng m(-3)), Fe (197.1-3724.9 ng m(-3)), Pt (65.9-2054.5 ng m(-3)), and P (11.0-756.6 ng m(-3)( for PM10. In the suburban sampling site, the most abundant detected metals were Al (2083.0-9664.0 ng m(-3)), Fe (360.0-7221.5 ng m(-3)), P (229.4-870.5 ng m(-3)), and Ti (137.3-849.7 ng m(-3)) for TSP and Al (218.5-4179.6 ng m(-3)), Fe (106.3-2005.1 ng m(-3)), P (251.9-908.4 ng m(-3)), and Ba (10.6-584.9 ng m(-3)) for PM10. For the crustal soil, the most abundant detected elements included Al (60,088-60,694 ppm), Fe (19,886-20,474 ppm), Ti (894-3481 ppm), and Si (365-4246 ppm). Key emission sources were identified, and the concentrations contributed from individual sources were estimated. Enrichment factor (EF) explaining a preponderance of the variance in the data was applied to the datasets. EF calculations revealed that non-crustal trace elements were more enriched in the urban than suburban sampling sites. Results of the factor analysis on the elements showed that emissions from road traffic (involving oil and fuel combustions by vehicles, platinum group elements from vehicle exhaust, and resuspension of particulate matter from polluted soil) and construction dust from nearby construction sites and electricity generation plant were the major contributors of anthropogenic metals at ambient atmosphere in Tabriz. Results of this study elucidated the need for developing pollution control strategy, especially vehicle exhaust control, and creating green spaces around the city.

Targeting of VX2 Rabbit Liver Tumor by Selective Delivery of 3-Bromopyruvate: A Biodistribution and Survival Study

PubMed Central

Vali, Mustafa; Vossen, Josephina A.; Buijs, Manon; Engles, James M.; Liapi, Eleni; Ventura, Veronica Prieto; Khwaja, Afsheen; Acha-Ngwodo, Obele; Shanmugasundaram, Ganapathy; Syed, Labiq; Wahl, Richard L.; Geschwind, Jean-Francois H.

2009-01-01

The aim of this study was to determine the biodistribution and tumor targeting ability of 14C-labeled 3-bromopyruvate ([14C]3-BrPA) after i.a. and i.v. delivery in the VX2 rabbit model. In addition, we evaluated the effects of [14C]3-BrPA on tumor and healthy tissue glucose metabolism by determining 18F-deoxyglucose (FDG) uptake. Last, we determined the survival benefit of i.a. administered 3-BrPA. In total, 60 rabbits with VX2 liver tumor received either 1.75 mM [14C]3-BrPA i.a., 1.75 mM [14C]3-BrPA i.v., 20 mM [14C]3-BrPA i.v., or 25 ml of phosphate-buffered saline (PBS). All rabbits (with the exception of the 20 mM i.v. group) received FDG 1 h before sacrifice. Next, we compared survival of animals treated with i.a. administered 1.75 mM [14C]3-BrPA in 25 ml of PBS (n = 22) with controls (n = 10). After i.a. infusion, tumor uptake of [14C]3-BrPA was 1.8 ± 0.2% percentage of injected dose per gram of tissue (%ID/g), whereas other tissues showed minimal uptake. After i.v. infusion (1.75 mM), tumor uptake of [14C]3-BrPA was 0.03 ± 0.01% ID/g. After i.a. administration of [14C]3-BrPA, tumor uptake of FDG was 26 times lower than in controls. After i.v. administration of [14C]3-BrPA, there was no significant difference in tumor FDG uptake. Survival analysis showed that rabbits treated with 1.75 mM 3-BrPA survived longer (55 days) than controls (18.6 days). Intra-arterially delivered 3-BrPA has a favorable biodistribution profile, combining a high tumor uptake resulting in blockage of FDG uptake with no effects on healthy tissue. The local control of the liver tumor by 3-BrPA resulted in a significant survival benefit. PMID:18591216

Biochemical Characterization of 3-Methyl-4-nitrophenol Degradation in Burkholderia sp. Strain SJ98

PubMed Central

Min, Jun; Lu, Yang; Hu, Xiaoke; Zhou, Ning-Yi

2016-01-01

Several strains have been reported to grow on 3-methyl-4-nitrophenol (3M4NP), the primary breakdown product of the excessively used insecticide fenitrothion. However, the microbial degradation of 3M4NP at molecular and biochemical levels remains unknown. Here, methyl-1,4-benzoquinone (MBQ) and methylhydroquinone (MHQ), rather than catechol proposed previously, were identified as the intermediates before ring cleavage during 3M4NP degradation by Burkholderia sp. strain SJ98. Real-time quantitative PCR analysis indicated that the pnpABA1CDEF cluster involved in para-nitrophenol (PNP) and 2-chloro-4-nitrophenol (2C4NP) catabolism was also likely responsible for 3M4NP degradation in this strain. Purified PNP 4-monooxygenase (PnpA) is able to catalyze the monooxygenation of 3M4NP to MBQ and exhibited an apparent Km value of 20.3 ± 2.54 μM for 3M4NP, and pnpA is absolutely necessary for the catabolism of 3M4NP by gene knock-out and complementation. PnpB, a 1,4-benzoquinone reductase catalyzes the reduction of MBQ to MHQ, and also found to enhance PnpA activity in vitro in the conversion of 3M4NP to MBQ. By sequential catalysis assays, PnpCD, PnpE, and PnpF were likely involved in the lower pathway of 3M4NP catabolism. Although NpcCD, NpcE, and NpcF are able to catalyze the sequential conversion of MHQ in vitro, these enzymes are unlikely involved in 3M4NP catabolism because their coding genes were not upregulated by 3M4NP induction in vivo. These results revealed that the enzymes involved in PNP and 2C4NP catabolism were also responsible for 3M4NP degradation in strain SJ98. This fills a gap in our understanding of the microbial degradation of 3M4NP at molecular and biochemical levels and also provides another example to illustrate the adaptive flexibility in microbial catabolism for structurally similar compounds. PMID:27252697

Limb-bud and Heart Overexpression Inhibits the Proliferation and Migration of PC3M Cells.

PubMed

Liu, Qicai; Li, Ermao; Huang, Long; Cheng, Minsheng; Li, Li

2018-01-01

Background: The limb-bud and heart gene ( LBH ) was discovered in the early 21st century and is specifically expressed in the mouse embryonic limb and heart development. Increasing evidences have indicated that LBH not only plays an important role in embryo development, it is also closely correlated with the occurance and progression of many tumors. However, its function in prostate cancer (PCa) is still not well understood. Here, we explored the effects of LBH on the proliferation and migration of the PCa cell line PC3M. Methods: LBH expression in tissues and cell lines of PCa was detected by immunohistochemistry and Western blotting. Lentivirus was used to transduct the LBH gene into the PC3M cells. Stable LBH-overexpressing PC3M-LBH cells and PC3M-NC control cells were obtained via puromycin screening. Cell proliferation was examined using the 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Cell cycle distribution and apoptosis rate were investigated using flow cytometry. Cell migration was studied using the Transwell assay. Results: LBH expression level was down-regulated in 3 different PCa cell lines, especially in PC3M cells, compared with the normal prostate epithelial cells(RWPE-1). Cell lines of LBH-upregulated PC3M-LBH and PC3M-NC control were successfully constructed. Significantly increased LBH expression level and decreased cyclin D1 and cyclin E2 expression level was found in PC3M-LBH cells as compared to the PC3M-NC cells. The overexpression of LBH significantly inhibited PC3M cell proliferation in vitro and tumor growth in nude mice. LBH overexpression in PC3M cell, also induced cell cycle G0/G1 phase arrest and decreased the migration of PC3M cells. Conclusions : Our results reveal that LBH expression is down-regulated in the tissue and cell lines of PCa. LBH overexpression inhibits PC3M cell proliferation and tumor growth by inducing cell cycle arrest through down-regulating cyclin D1and cyclin E2 expression. LBH might be a therapeutic target and potential diagnostic marker in PCa.

Receptor Subtype Alterations: Bases of Neuronal Plasticity and Learning

DTIC Science & Technology

1990-12-18

oxotremorine -M binding in rabbit anterior thalamus and cingulate cortex increased during the course of discriminative avoidance conditioning (DAC). Since there...anterior thalamus between training-induced neuronal plasticities and changes in oxotremorine -M binding. 3) The concentrations of noradrenaline, serotonin...binding protocols included the following: M 1, 3H-pirenzepine; M 2, 3H- oxotremorine -M in the p resence of unlabeled pirenzepine; GABAA, 3H-muscimol; M, and

Effects of BRL 38227 on neurally-mediated responses in the guinea-pig isolated bronchus.

PubMed

Good, D M; Clapham, J C; Hamilton, T C

1992-04-01

1. In guinea-pig isolated bronchus treated with indomethacin (2.8 microM), electrical field stimulation (EFS; 10 Hz, 0.5 ms, 60-70 V, for 10 s) evoked a tetrodotoxin (3 microM)-sensitive, biphasic contraction comprising a rapid, atropine (1 microM)-sensitive cholinergic response succeeded by a slowly developing, capsaicin (10 microM)-sensitive, non-adrenergic, non-cholinergic excitatory (NANCe) response. 2. BRL 38227 (0.3-3 microM), salmeterol (0.003-3 microM) and ketotifen (1.0-300 microM) each produced concentration-dependent inhibition of both NANCe and cholinergic responses to EFS in guinea-pig isolated bronchus. 3. Substance P (SP; 1 microM) and neurokinin A (NKA; 0.07 microM) produced contractions equivalent in magnitude to the NANCe response to EFS, which were inhibited by salmeterol (1 microM), but not by BRL 38227 (3 microM) or ketotifen (100 microM). 4. Acetylcholine (ACh; 6 microM) was equi-effective with the electrical activation of cholinergic neurones. BRL 38227 (3 microM) slightly inhibited responses to ACh (6 microM). Salmeterol (1 microM) and ketotifen (100 microM) markedly inhibited responses to ACh (6 microM). 5. In bronchial rings pre-contracted with ACh (100 microM), BRL 38227 (0.1-30 microM), salmeterol (0.001-3 microM) and ketotifen (0.1-100 microM) each produced concentration-dependent relaxation. Unlike ketotifen, BRL 38227 and salmeterol only partially (18.8 +/- 2.1% and 51.8 +/- 3.9% respectively) reversed the ACh-induced contraction. 6. The (+)-analogue of BRL 38227, BRL 38226 (0.3-100 microM), was without effect on responses to EFS and had no effect on the inhibition caused by BRL 38227. The K+-channel activators pinacidil (3.0-30 microM) and RP 52891 (3.0-30 microM) exerted similar inhibitory actions on responses to EFS as BRL 38227, but were less potent. Glibenclamide (0.1-1.O microM) and phentolamine (3 microM) antagonized the inhibitory effects of BRL 38227 on responses to EFS.7. It is concluded that BRL 38227 and ketotifen can inhibit NANCe neuroeffector transmission at concentrations exerting little or no inhibitory effects on responses to exogenously applied tachykinins.By contrast, in addition to suppressing NANCe responses to EFS, salmeterol also markedly inhibits responses to SP and NKA. At concentrations markedly suppressing cholinergic neuroeffector transmission, BRL 38227 has only minor effects on responses to exogenously-applied ACh. Salmeterol and ketotifen both depress responses to ACh within the concentration-range over which they inhibit cholinergic responses to EFS. The inhibitory effects of BRL 38227 on responses to EFS exhibit stereo-specificity and may involve the opening of a neuronal K+-channel. This K+-channel is glibenclamide-and phentolamine-sensitive and appears similar to the smooth muscle K+-channel which is modulated by BRL 38227.

Gd2O3 nanoparticles stabilized by hydrothermally modified dextrose for positive contrast magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Babić-Stojić, Branka; Jokanović, Vukoman; Milivojević, Dušan; Požek, Miroslav; Jagličić, Zvonko; Makovec, Darko; Arsikin, Katarina; Paunović, Verica

2016-04-01

Gd2O3 nanoparticles of a few nm in size and their agglomerates dispersed in dextrose derived polymer template were synthesized by hydrothermal treatment. The produced nanosized material was investigated by TEM, FTIR spectroscopy, SQUID measurements and NMR relaxometry. Biological evaluation of this material was done by crystal violet and MTT assays to determine the cell viability. Longitudinal and transverse NMR relaxivities of water diluted Gd2O3 nanoparticle dispersions measured at the magnetic field of 1.5 T, estimated to be r1(Gd2O3)=9.6 s-1 mM-1 in the Gd concentration range 0.1-30 mM and r2(Gd2O3)=17.7 s-1 mM-1 in the lower concentration range 0.1-0.8 mM, are significantly higher than the corresponding relaxivities measured for the standard contrast agent r1(Gd-DTPA)=4.1 s-1 mM-1 and r2(Gd-DTPA)=5.1 s-1 mM-1. The ratio of the two relaxivities for Gd2O3 nanoparticles r2/r1=1.8 is suitable for T1-weighted imaging. Good MRI signal intensities of the water diluted Gd2O3 nanoparticle dispersions were recorded at lower Gd concentrations 0.2-0.8 mM. The Gd2O3 samples did not exert any significant cytotoxic effects at Gd concentrations of 0.2 mM and below. These properties of the produced Gd2O3 nanoparticles in hydrothermally modified dextrose make them promising for potential application in MRI for the design of a positive MRI contrast agent.

Sustained Immunogenicity of 2-dose Human Papillomavirus 16/18 AS04-adjuvanted Vaccine Schedules in Girls Aged 9–14 Years: A Randomized Trial

PubMed Central

Puthanakit, Thanyawee; Cheng-Hsun, Chiu; Ren-Bin, Tang; Schwarz, Tino; Pellegrino, Angelo; Esposito, Susanna; Frenette, Louise; McNeil, Shelly; Durando, Paolo; Rheault, Paul; Giaquinto, Carlo; Horn, Michael; Petry, Karl Ulrich; Peters, Klaus; Azhar, Toma; Hillemanns, Peter; De Simoni, Stephanie; Friel, Damien; Pemmaraju, Suryakiran; Hezareh, Marjan; Thomas, Florence; Descamps, Dominique; Folschweiller, Nicolas; Struyf, Frank

2017-01-01

Abstract Background. We previously reported the noninferiority 1 month after the last dose of 2-dose human papillomavirus 16/18 AS04-adjuvanted (AS04-HPV-16/18) vaccine schedules at months 0 and 6 (2D_M0,6) and months 0 and 12 (2D_M0,12) in girls aged 9–14 years compared with a 3-dose schedule at months 0, 1, and 6 (3D_M0,1,6) in women aged 15–25 years. Here, we report the results at study end (month 36 [M36]). Methods. Girls were randomized 1:1 and received 2 vaccine doses either 6 months (2D_M0,6) or 12 months apart (2D_M0,12); women received 3 doses at months 0, 1, and 6 (3D_M0,1,6). Endpoints included noninferiority of HPV-16/18 antibodies for 2D_M0,6 versus 3D_M0,1,6; 2D_M0,12 versus 3D_M0,1,6; and 2D_M0,12 versus 2D_M0,6; and assessment of neutralizing antibodies, T cells, B cells, and safety. Results. At M36, the 2D_M0,6 and 2D_M0,12 schedules remained noninferior to the 3D_M0,1,6 schedule in terms of seroconversion rates and 3D/2D geometric mean titers for anti-HPV-16 and anti-HPV-18. All schedules elicited sustained immune responses up to M36. Conclusions. Both 2-dose schedules in young girls remained noninferior to the 3-dose schedule in women up to study conclusion at M36. The AS04-HPV-16/18 vaccine administered as a 2-dose schedule was immunogenic and well tolerated in young girls. PMID:28591778

Calmodulin is a phospholipase C-beta interacting protein.

PubMed

McCullar, Jennifer S; Larsen, Shana A; Millimaki, Ryan A; Filtz, Theresa M

2003-09-05

Phospholipase C-beta 3 (PLC beta 3) is an important effector enzyme in G protein-coupled signaling pathways. Activation of PLC beta 3 by G alpha and G beta gamma subunits has been fairly well characterized, but little is known about other protein interactions that may also regulate PLC beta 3 function. A yeast two-hybrid screen of a mouse brain cDNA library with the amino terminus of PLC beta 3 has yielded potential PLC beta 3 interacting proteins including calmodulin (CaM). Physical interaction between CaM and PLC beta 3 is supported by a positive secondary screen in yeast and the identification of a CaM binding site in the amino terminus of PLC beta 3. Co-precipitation of in vitro translated and transcribed amino- and carboxyl-terminal PLC beta 3 revealed CaM binding at a putative amino-terminal binding site. Direct physical interaction of PLC beta 3 and PLC beta 1 isoforms with CaM is supported by pull-down of both isoenzymes with CaM-Sepharose beads from 1321N1 cell lysates. CaM inhibitors reduced M1-muscarinic receptor stimulation of inositol phospholipid hydrolysis in 1321N1 astrocytoma cells consistent with a physiologic role for CaM in modulation of PLC beta activity. There was no effect of CaM kinase II inhibitors, KN-93 and KN-62, on M1-muscarinic receptor stimulation of inositol phosphate hydrolysis, consistent with a direct interaction between PLC beta isoforms and CaM.

[Comparison between porous polymer carrier and activated carbon carrier used for treating organic wastewater in anaerobic fluidized-bed reactor].

PubMed

Yang, P; Fang, Z; Shi, Y

2001-01-01

A comparative performance between porous polymer carriers (HP) and granular activated carbon carriers (GAC) in anaerobic fluidied-bed reactors was undertaken to evaluate their characters. The results showed that the COD removal and the biogas volume yield rate were 84% and 16.5 m3/(m3.d) respectively when HP was used as carrier to treat synthetic wastewater, at the top COD organic load rate of 65.5 kg/(m3.d), however those were 74.2% and 14.5% respectively for GAC carrier at the top load rate of 63.25 kg/(m3.d). The COD removal and biogas volume yield rate were 64.7%-54.5% and 1.89-2.7 m3/(m3.d) respectively when HP was used as carriers to treat straw pulping wastewater, at the load rate of 14.5-36.15 kg/(m3.d), and those were 61.0%-52.1% and 0.73-2.0 m3/(m3.d) respectively for GAC carriers at the load rate 9.16-19.06 kg/(m3.d). The study revealed that the HP carriers reactor is more efficient than the GAC carriers reactor in microbial immobilization and the wastewater treatment.

GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pierce, R. A.

2012-03-12

HB-Line will begin processing Pu solutions during FY2012 that will involve the recovery of Pu using oxalate precipitation and filtration. After the precipitation and filtration processes, the filtrate solution will be transferred from HB-Line to H-Canyon. The presence of excess oxalate and unfiltered Pu oxalate solids in these solutions create a criticality safety issue if they are sent to H-Canyon without controls in H-Canyon. One approach involves H-Canyon receiving the filtrate solution into a tank that is poisoned with soluble gadolinium (Gd). Decomposition of the oxalate will occur within a subsequent H-Canyon vessel. The receipt of excess oxalate into themore » H-Canyon receipt tanks has the potential to precipitate a portion of the Gd poison in the receipt tanks. Because the amount of Gd in solution determines the maximum amount of Pu solids that H-Canyon can receive, H-Canyon Engineering requested that SRNL determine the solubility of Gd in aqueous solutions of 4-10 M nitric acid (HNO{sub 3}), 4-12 g/L Gd, and 0.15-0.25 M oxalic acid (H{sub 2}C{sub 2}O{sub 4}) at 25 °C. The target soluble Gd concentration is 6 g/L. The data indicate that the target can be achieved above 6 M HNO{sub 3} and below 0.25 M H{sub 2}C{sub 2}O{sub 4}. At 25 °C, for 6 M HNO{sub 3}, 11 g/L and 7 g/L Gd are soluble in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. In 4 M HNO{sub 3}, the Gd solubility drops significantly to 2.5 g/L and 0.8 g/L in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. The solubility of Gd at 8-10 M HNO{sub 3} exceeds the solubility at 6 M HNO{sub 3}. The data for 4 M HNO{sub 3} showed good agreement with data in the literature. To achieve a target of 6 g/L soluble Gd in solution in the presence of 0.15-0.25 M oxalate, the HNO{sub 3} concentration must be maintained at or above 6 M HNO{sub 3}. The solubility of Gd in 4 M HNO{sub 3} with 0.15 M oxalate at 10 °C is about 1.5 g/L. For 6 M HNO{sub 3} with 0.15 M oxalate, the solubility of Gd at 10 °C is about 10 g/L. Gadolinium nitrate is very soluble in HNO{sub 3}. The solubility of Gd is linear as a function of HNO{sub 3} from 343 g/L Gd in 2.88 M HNO{sub 3} to 149 g/L in 8.16 M HNO{sub 3}. Below 2.88 M HNO{sub 3}, the solubility of Gd approaches a limit of about 360 g/L. However, there are no data available below 1.40 M HNO{sub 3}, which has a Gd solubility of 353 g/L.« less

Metal-metal bonding and aromaticity in [M2(NHCHNH)3]2 (μ-E)2 (E = O, S; M = Nb, Mo, Tc, Ru, Rh).

PubMed

Yan, Xiuli; Meng, Lingpeng; Sun, Zheng; Li, Xiaoyan

2016-02-01

The nature of M-M bonding and aromaticity of [M2(NHCHNH)3]2(μ-E)2 (E = O, S; M = Nb, Mo, Tc, Ru, Rh) was investigated using atoms in molecules (AIM) theory, electron localization function (ELF), natural bond orbital (NBO) and molecular orbital analysis. These analyses led to the following main conclusions: in [M2(NHCHNH)3]2(μ-E)2 (E = O, S; M = Nb, Mo, Tc, Ru, Rh), the Nb-Nb, Ru-Ru, and Rh-Rh bonds belong to "metallic" bonds, whereas Mo-Mo and Tc-Tc drifted toward the "dative" side; all these bonds are partially covalent in character. The Nb-Nb, Mo-Mo, and Tc-Tc bonds are stronger than Ru-Ru and Rh-Rh bonds. The M-M bonds in [M2(NHCHNH)3]2(μ-S)2 are stronger than those in [M2(NHCHNH)3]2(μ-O)2 for M = Nb, Mo, Tc, and Ru. The NICS(1)ZZ values show that all of the studied molecules, except [Ru2(NHCHNH)3]2(μ-O)2, are aromaticity molecules. O-bridged compounds have more aromaticity than S-bridged compounds. Graphical Abstract Left Molecular graph, and right electron localization function (ELF) isosurface of [M2(NHCHNH)3]2(μ-E)2(E = O, S; M = Nb, Mo, Tc, Ru, Rh).

Novel oxotremorine-related heterocyclic derivatives: Synthesis and in vitro pharmacology at the muscarinic receptor subtypes.

PubMed

Dallanoce, Clelia; De Amici, Marco; Barocelli, Elisabetta; Bertoni, Simona; Roth, Bryan L; Ernsberger, Paul; De Micheli, Carlo

2007-12-15

A set of novel heterocyclic ligands (6-27) structurally related to Oxotremorine 2 was designed, synthesized and tested at muscarinic receptor subtypes (mAChRs). In the binding experiments at cloned human receptors (hm1-5), compounds 7 and 15 evidenced a remarkable affinity and selectivity for the hm2 subtype. The in vitro functional assays, performed on a selected group of derivatives at M(1), M(2), and M(3) tissue preparations, singled out the 3-butynyloxy-5-methylisoxazole trimethylammonium salt 7 as a potent unselective muscarinic agonist [pEC(50): 7.40 (M(1)), 8.18 (M(2)), and 8.14 (M(3))], whereas its 5-phenyl analogue 12 behaved as a muscarinic antagonist, slightly selective for the M(1) subtype [pK(B): 6.88 (M(1)), 5.95 (M(2)), 5.53 (M(3))]. Moreover, the functional data put in evidence that the presence of the piperidine ring may generate a functional selectivity, e.g., an M(1) antagonist/M(2) partial agonist/M(3) full agonist profile (compound 21), at variance with the corresponding quaternary ammonium salt (compound 22) which behaved as a muscarinic agonist at all M(1-3) receptors, with an appreciable selectivity for the cardiac M(2) receptors.

Effect of Metformin on Viability, Morphology, and Ultrastructure of Mouse Bone Marrow-Derived Multipotent Mesenchymal Stromal Cells and Balb/3T3 Embryonic Fibroblast Cell Line

PubMed Central

Czyrek, Aleksandra; Basinska, Katarzyna; Trynda, Justyna; Skaradzińska, Aneta; Siudzińska, Anna; Marycz, Krzysztof

2015-01-01

Metformin, a popular drug used to treat diabetes, has recently gained attention as a potentially useful therapeutic agent for treating cancer. In our research metformin was added to in vitro cultures of bone marrow-derived multipotent mesenchymal stromal cells (BMSCs) and Balb/3T3 fibroblast at concentration of 1 mM, 5 mM, and 10 mM. Obtained results indicated that metformin negatively affected proliferation activity of investigated cells. The drug triggered the formation of autophagosomes and apoptotic bodies in all tested cultures. Additionally, we focused on determination of expression of genes involved in insulin-like growth factor 2 (IGF2) signaling pathway. The most striking finding was that the mRNA level of IGF2 was constant in both BMSCs and Balb/3T3. Further, the analysis of IGF2 concentration in cell supernatants showed that it decreased in BMSC cultures after 5 and 10 mM metformin treatments. In case of Balb/3T3 the concentration of IGF2 in culture supernatants decreased after 1 and 5 mM and increased after 10 mM of metformin. Our results suggest that metformin influences the cytophysiology of somatic cells in a dose- and time-dependent manner causing inhibition of proliferation and abnormalities of their morphology and ultrastructure. PMID:26064951

The role of CYP2D6 in primary and secondary oxidative metabolism of dextromethorphan: in vitro studies using human liver microsomes.

PubMed Central

Kerry, N L; Somogyi, A A; Bochner, F; Mikus, G

1994-01-01

1. The enzyme kinetics of dextromethorphan O-demethylation in liver microsomes from three extensive metabolisers (EM) with respect to CYP2D6 indicated high (Km1 2.2-9.4 microM) and low (Km2 55.5-307.3 microM) affinity sites whereas microsomes from two poor metabolisers (PM) indicated a single site (Km 560 and 157 microM). Similar differences were shown for 3-methoxymorphinan O-demethylation to 3-hydroxymorphinan (Km 6.9-9.6 microM in EM subjects; Km 307 and 213 microM in PM subjects). 2. Dextromethorphan O-demethylation was inhibited competitively by quinidine (Ki 0.1 microM), rac-perhexiline (Ki 0.4 microM), dextropropoxyphene (Ki 6 microM), rac-methadone (Ki 8 microM), and 3-methoxymorphinan (Ki 15 microM). These compounds were also potent inhibitors of 3-methoxymorphinan O-demethylation with IC50 values ranging from 0.02-12 microM. Anti-LKM1 serum inhibited both dextromethorphan and 3-methoxymorphinan O-demethylations in a titre-dependent manner. 3. The Michaelis-Menten constant for dextromethorphan N-demethylation to 3-methoxymorphinan (Km 632-977 microM) and dextrorphan N-demethylation to 3-hydroxymorphinan (Km 1571-4286 microM) did not differ between EM and PM microsomes. These N-demethylation reactions were not inhibited by quinidine and rac-methadone or LKM1 antibodies. 4. Dextromethorphan and 3-methoxymorphinan are metabolised by the same P450 isoform, CYP2D6, whereas the N-demethylation reactions are not carried out by CYP2D6. PMID:7826826

Effect of lipoic acid on paraoxonase-1 and paraoxonase-3 protein levels, mRNA expression and arylesterase activity in liver hepatoma cells.

PubMed

Ozgun, Eray; Sayilan Ozgun, Gulben; Tabakcioglu, Kiymet; Suer Gokmen, Selma; Sut, Necdet; Eskiocak, Sevgi

2017-10-01

Paraoxonase-1 (PON1) and PON3 (PON3) are anti-atherosclerotic enzymes, synthesized primarily in liver and bound to HDL in circulation. The aim of the present study was to investigate the effects of therapeutic doses of lipoic acid on PON1 and PON3 protein levels, mRNA expression and arylesterase activity in liver. We treated HepG2 cells with 10, 40 and 200 μM lipoic acid for 72 h. Cell viability was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. PON1 and PON3 protein levels were measured by Western blotting, their mRNA expression was measured by quantitative PCR and arylesterase activity was measured spectrophotometrically. 200 µM lipoic acid caused a significant increase on PON1 and PON3 protein levels and arylesterase activity as compared with control, 10 µM and 40 µM lipoic acid-treated cells. 200 µM lipoic acid also caused a significant decrease on PON1 mRNA expression whereas on a significant increase PON3 mRNA expression as compared with control, 10 µM and 40 µM lipoic acid-treated cells. Our study showed that although lipoic acid up-regulates PON3 but down-regulates PON1 mRNA expression, it increases both PON1 and PON3 protein levels and arylesterase activity in HepG2 cells. We can report that lipoic acid may be useful for preventing atherosclerosis at therapeutic doses.

Biodegradation of phenol in batch and continuous flow microbial fuel cells with rod and granular graphite electrodes.

PubMed

Moreno, Lyman; Nemati, Mehdi; Predicala, Bernardo

2018-01-01

Phenol biodegradation was evaluated in batch and continuous flow microbial fuel cells (MFCs). In batch-operated MFCs, biodegradation of 100-1000 mg L -1 phenol was four to six times faster when graphite granules were used instead of rods (3.5-4.8 mg L -1  h -1 vs 0.5-0.9 mg L -1  h -1 ). Similarly maximum phenol biodegradation rates in continuous MFCs with granular and single-rod electrodes were 11.5 and 0.8 mg L -1  h -1 , respectively. This superior performance was also evident in terms of electrochemical outputs, whereby continuous flow MFCs with granular graphite electrodes achieved maximum current and power densities (3444.4 mA m -3 and 777.8 mW m -3 ) that were markedly higher than those with single-rod electrodes (37.3 mA m -3 and 0.8 mW m -3 ). Addition of neutral red enhanced the electrochemical outputs to 5714.3 mA m -3 and 1428.6 mW m -3 . Using the data generated in the continuous flow MFC, biokinetic parameters including μ m , K S , Y and K e were determined as 0.03 h -1 , 24.2 mg L -1 , 0.25 mg cell (mg phenol) -1 and 3.7 × 10 -4  h -1 , respectively. Access to detailed kinetic information generated in MFC environmental conditions is critical in the design, operation and control of large-scale treatment systems utilizing MFC technology.

mTORC1 is necessary but mTORC2 and GSK3β are inhibitory for AKT3-induced axon regeneration in the central nervous system.

PubMed

Miao, Linqing; Yang, Liu; Huang, Haoliang; Liang, Feisi; Ling, Chen; Hu, Yang

2016-03-30

Injured mature CNS axons do not regenerate in mammals. Deletion of PTEN, the negative regulator of PI3K, induces CNS axon regeneration through the activation of PI3K-mTOR signaling. We have conducted an extensive molecular dissection of the cross-regulating mechanisms in axon regeneration that involve the downstream effectors of PI3K, AKT and the two mTOR complexes (mTORC1 and mTORC2). We found that the predominant AKT isoform in CNS, AKT3, induces much more robust axon regeneration than AKT1 and that activation of mTORC1 and inhibition of GSK3β are two critical parallel pathways for AKT-induced axon regeneration. Surprisingly, phosphorylation of T308 and S473 of AKT play opposite roles in GSK3β phosphorylation and inhibition, by which mTORC2 and pAKT-S473 negatively regulate axon regeneration. Thus, our study revealed a complex neuron-intrinsic balancing mechanism involving AKT as the nodal point of PI3K, mTORC1/2 and GSK3β that coordinates both positive and negative cues to regulate adult CNS axon regeneration.

Toward a feline-optimized culture medium: impact of ions, carbohydrates, essential amino acids, vitamins, and serum on development and metabolism of in vitro fertilization-derived feline embryos relative to embryos grown in vivo.

PubMed

Herrick, Jason R; Bond, Jennifer B; Magarey, Genevieve M; Bateman, Helen L; Krisher, Rebecca L; Dunford, Susan A; Swanson, William F

2007-05-01

The objective of this study was to define the physiologic needs of domestic cat embryos to facilitate development of a feline-specific culture medium. In a series of factorial experiments, in vivo-matured oocytes (n = 2040) from gonadotropin-treated domestic cats were inseminated in vitro to generate embryos (n = 1464) for culture. In the initial study, concentrations of NaCl (100.0 vs. 120.0 mM), KCl (4.0 vs. 8.0 mM), KH(2)PO(4) (0.25 vs. 1.0 mM), and the ratio of CaCl(2) to MgSO(4)-7H(2)O (1.0:2.0 mM vs. 2.0:1.0 mM) in the medium were evaluated during Days 1-6 (Day 0: oocyte recovery and in vitro fertilization [IVF]) of culture. Subsequent experiments assessed the effects of varying concentrations of carbohydrate (glucose, 1.5, 3.0, or 6.0 mM; l-lactate, 3.0, 6.0, or 12.0 mM; and pyruvate, 0.1 or 1.0 mM) and essential amino acids (EAAs; 0, 0.5, or 1.0x) in the medium during Days 1-3 and Days 3-6 of culture. Inclusion of vitamins (0 vs. 1.0x) and fetal calf serum (FCS; 0 vs. 5% [v/v]) in the medium also was evaluated during Days 3-6. Development and metabolism of IVF embryos on Day 3 or Day 6 were compared to age-matched in vivo embryos recovered from naturally mated queens. A feline-optimized culture medium (FOCM) was formulated based on these results (100.0 mM NaCl, 8.0 mM KCl, 1.0 mM KH(2)PO(4), 2.0 mM CaCl(2), 1.0 mM MgSO(4), 1.5 mM glucose, 6.0 mM L-lactate, 0.1 mM pyruvate, and 0x EAAs with 25.0 mM NaHCO(3), 1.0 mM alanyl-glutamine, 0.1 mM taurine, and 1.0x nonessential amino acids) with 0.4% (w/v) BSA from Days 0-3 and 5% FCS from Days 3-6. Using this medium, ~70% of cleaved embryos developed into blastocysts with profiles of carbohydrate metabolism similar to in vivo embryos. Our results suggest that feline embryos have stage-specific responses to carbohydrates and are sensitive to EAAs but are still reliant on one or more unidentified components of FCS for optimal blastocyst development.

Exposure assessment of workplace manufacturing titanium dioxide particles

NASA Astrophysics Data System (ADS)

Xu, Huadong; Zhao, Lin; Chen, Zhangjian; Zhou, Jingwen; Tang, Shichuan; Kong, Fanling; Li, Xinwei; Yan, Ling; Zhang, Ji; Jia, Guang

2016-10-01

With the widespread use of titanium dioxide (TiO2) human exposure is inevitable, but the exposure data on TiO2 are still limited. This study adopted off-line filter-based sampling combined with real-time activity-based monitoring to measure the concentrations in a workplace manufacturing TiO2 (primary diameter: 194 ± 108 nm). Mass concentrations (MCs) of aerosol particles in the packaging workshop (total dust: 3.17 mg/m3, nano dust: 1.22 mg/m3) were much higher than those in the milling workshop (total dust: 0.79 mg/m3, nano dust: 0.31 mg/m3) and executive office (total dust: 0.44 mg/m3, nano dust: 0.19 mg/m3). However, the MCs of TiO2 were at a relatively low level in the packaging workshop (total TiO2: 46.4 μg/m3, nano TiO2: 16.7 μg/m3) and milling workshop (total TiO2: 39.4 μg/m3, nano TiO2: 19.4 μg/m3) by ICP-MS. The number concentration (NC), surface area concentration (SAC) of aerosol particles potentially deposited in alveolar (SACA), and tracheobronchial (SACTB) regions of lungs in the packaging workshop were (1.04 ± 0.89) × 105 particles/cm3, 414.49 ± 395.07, and 86.01 ± 83.18 μm2/cm3, respectively, which were all significantly higher than those of the milling workshop [(0.12 ± 0.40) × 105 particles/cm3, 75.38 ± 45.23, and 17.60 ± 9.22 μm2/cm3, respectively] as well as executive office and outdoor background ( p < 0.05). Activity-related characteristics were found in both workshops, and the time-variant characteristics showed very similar trends for 3 days in the packaging workshop. Our study provides important data of TiO2 particles exposure in the workplace.

Metabolism of Ginger Component [6]-Shogaol in Liver Microsomes from Mouse, Rat, Dog, Monkey, and Human

PubMed Central

Chen, Huadong; Soroka, Dominique; Zhu, Yingdong; Sang, Shengmin

2013-01-01

Scope There are limited data on the metabolism of [6]-shogaol, a major bioactive component of ginger. This study demonstrates metabolism of [6]-shogaol in liver microsomes from mouse, rat, dog, monkey, and human. Methods and results The in vitro metabolism of [6]-shogaol was compared among five species using liver microsomes from mouse, rat, dog, monkey, and human. Following incubations with [6]-shogaol, three major reductive metabolites 1-(4'-hydroxy-3'-methoxyphenyl)-4-decen-3-ol (M6), 1-(4′-hydroxy-3′-methoxyphenyl)-decan-3-ol (M9), and 1-(4'-hydroxy-3'-methoxyphenyl)-decan-3-one (M11), as well as two new oxidative metabolites (1E, 4E)-1-(4'-hydroxy-3'-methoxyphenyl)-deca-1,4-dien-3-one (M14) and (E)-1-(4'-hydroxy-3'-methoxyphenyl)-dec-1-en-3-one (M15) were found in all species. The kinetic parameters of M6 in liver microsomes from each respective species were quantified using Michaelis-Menten theory. A broad CYP-450 inhibitor, 1-aminobenzotriazole, precluded the formation of oxidative metabolites M14 and M15, and 18β-glycyrrhetinic acid, an aldo-keto reductase inhibitor, eradicated the formation of the reductive metabolites M6, M9, and M11 in all species. Metabolites M14 and M15 were tested for cancer cell growth inhibition and induction of apoptosis and both showed substantial activity, with M14 displaying greater potency than [6]-shogaol. Conclusion We conclude that [6]-shogaol is metabolized extensively in mammalian species mouse, rat, dog, monkey, and human, and that there are significant interspecies differences to consider when planning pre-clinical trials towards [6]-shogaol chemoprevention. PMID:23322474

Metabolism of ginger component [6]-shogaol in liver microsomes from mouse, rat, dog, monkey, and human.

PubMed

Chen, Huadong; Soroka, Dominique; Zhu, Yingdong; Sang, Shengmin

2013-05-01

There are limited data on the metabolism of [6]-shogaol (6S), a major bioactive component of ginger. This study demonstrates metabolism of 6S in liver microsomes from mouse, rat, dog, monkey, and human. The in vitro metabolism of 6S was compared among five species using liver microsomes from mouse, rat, dog, monkey, and human. Following incubations with 6S, three major reductive metabolites 1-(4'-hydroxy-3'-methoxyphenyl)-4-decen-3-ol (M6), 1-(4'-hydroxy-3'-methoxyphenyl)-decan-3-ol (M9), and 1-(4'-hydroxy-3'-methoxyphenyl)-decan-3-one (M11), as well as two new oxidative metabolites (1E,4E)-1-(4'-hydroxy-3'-methoxyphenyl)-deca-1,4-dien-3-one (M14) and (E)-1-(4'-hydroxy-3'-methoxyphenyl)-dec-1-en-3-one (M15) were found in all species. The kinetic parameters of M6 in liver microsomes from each respective species were quantified using Michaelis-Menten theory. A broad CYP-450 inhibitor, 1-aminobenzotriazole, precluded the formation of oxidative metabolites, M14 and M15, and 18β-glycyrrhetinic acid, an aldo-keto reductase inhibitor, eradicated the formation of the reductive metabolites M6, M9, and M11 in all species. Metabolites M14 and M15 were tested for cancer cell growth inhibition and induction of apoptosis and both showed substantial activity, with M14 displaying greater potency than 6S. We conclude that 6S is metabolized extensively in mammalian species mouse, rat, dog, monkey, and human, and that there are significant interspecies differences to consider when planning preclinical trials toward 6S chemoprevention. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

GSK-3β and vitamin D receptor are involved in β-catenin and snail signaling in high glucose-induced epithelial-mesenchymal transition of mouse podocytes.

PubMed

Guo, Jia; Xia, Nannan; Yang, Lili; Zhou, Sijie; Zhang, Qian; Qiao, Yingjin; Liu, Zhangsuo

2014-01-01

Epithelial-mesenchymal transition (EMT) is recognized to play an important role in diabetic nephropathy (DN). To analyze the roles of glycogen synthase kinase 3β (GSK-3β), β-catenin and Snail signaling in high glucose (HG)-induced mouse podocytes EMT. Differentiated podocytes were divided into: the normal glucose group (NG: glucose 5.6mM), the HG groups (12.5HG: 12.5mM; 25HG: 25mM; and 50HG: 50mM of glucose), and the osmotic control group (NG+M: glucose 5.6mM and mannitol 44.4mM). GSK-3β, β-catenin and Snail were assessed using semi-quantitative RT-PCR, western blot and immunofluorescence. β-catenin and Snail pathways were assessed after down-regulating GSK-3β expression using an inhibitor (LiCl) or a small-interfering RNA (siRNA). HG increased GSK-3β, β-catenin and Snail expressions, and promoted EMT, as shown by decreased nephrin expression (epithelial marker), and increased α-SMA expression (mesenchymal marker). GSK-3β inhibitor and GSK-3β siRNA decreased β-catenin and Snail expressions, and reversed HG-induced EMT. Immunofluorescence showed that GSK-3β and β-catenin did not completely overlap; β-catenin was transferred to the nucleus in the 25HG group. VDR seems to be involved in HG-induced β-catenin nuclear translocation. Down-regulating GSK-3β expression decreased β-catenin and Snail expression and reversed HG-induced podocytes EMT. Thus, modulating GSK-3β might be a target to slow or prevent DN. © 2014 S. Karger AG, Basel. © 2014 S. Karger AG, Basel.

40 CFR Appendix A to Subpart Hhhh... - Method for Determining Free-Formaldehyde in Urea-Formaldehyde Resins by Sodium Sulfite (Iced...

Code of Federal Regulations, 2010 CFR

2010-07-01

... (class A). 3.2.5One 10-mL pipette (class A). 3.2.6One 50-mL graduated cylinder (class A). 3.2.7A pH meter, standardized using pH 7 and pH 10 buffers. 3.2.8Magnetic stirrer. 3.2.9Magnetic stirring bars. 3.2.10Several 5... mL of 1 M sodium sulfite into a stirred 250-mL beaker. 3.5.1.2Using a standardized pH meter, measure...

The effect of enamel porcelain thickness on color and the ability of a shade guide to prescribe chroma.

PubMed

Jarad, F D; Moss, B W; Youngson, C C; Russell, M D

2007-04-01

To test the null hypothesis that there is no color change when enamel porcelain thickness is changed and to evaluate the ability of a shade guide to prescribe chroma. Three shades (3M1, 3M2 and 3M3) were selected from a Vitapan 3D master shade guide. Five disk specimens were prepared for each shade, consisting of three layers (opacious dentin, dentin and enamel) at thicknesses of 0.6, 0.8 and 0.6mm, respectively. The color of each disk was measured using a spectrophotometer. Enamel porcelain was reduced in thickness to 0.3mm and porcelain disks were remeasured. Reducing the enamel thickness of porcelain disk specimens significantly increased L) (p<0.05), b*, metric chroma and hue angle (p<0.001). For the three shades studied (3M1, 3M2 and 3M3) L* values were not significantly different (p>0.05) and chroma increased for 3M1 with the lowest chroma to 3M3 with the highest chroma, which is in line with the shade guide specifications. Although statistically significant (p<0.001) changes in hue angle between the three shades were small (less than 3 degrees overall). The difference in chroma between the three shades 3M1, 3M2 and 3M3 was greatest for the thin enamel layer than the thick enamel layer. A change in enamel thickness from 0.6 to 0.3mm resulted in a three-unit change in L* and metric chroma and a 4 degrees change in hue angle. A change in enamel porcelain thickness will have a greater effect on higher chromatic shades than those with lower chroma. The ability of the shade guide to prescribe chroma was demonstrated but this could be offset by an anomalous enamel thickness.

Brand Cigarillos: Low Price but High Particulate Matter Levels—Is Their Favorable Taxation in the European Union Justified?

PubMed Central

Wasel, Julia; Boll, Michael; Schulze, Michaela; Mueller, Daniel; Bundschuh, Matthias; Groneberg, David A.; Gerber, Alexander

2015-01-01

Background: Second hand smoke (ETS)-associated particulate matter (PM) contributes considerably to indoor air contamination and constitutes a health risk for passive smokers. Easy to measure, PM is a useful parameter to estimate the dosage of ETS that passive smokers are exposed to. Apart from its suitability as a surrogate parameter for ETS-exposure, PM itself affects human morbidity and mortality in a dose-dependent manner. We think that ETS-associated PM should be considered an independent hazard factor, separately from the many other known harmful compounds of ETS. We believe that brand-specific and tobacco-product-specific differences in the release of PM matter and that these differences are of public interest. Methods: To generate ETS of cigarettes and cigarillos as standardized and reproducible as possible, an automatic second hand smoke emitter (AETSE) was developed and placed in a glass chamber. L&M cigarettes (“without additives”, “red label”, “blue label”), L&M filtered cigarillos (“red”) and 3R4F standard research cigarettes (as reference) were smoked automatically according to a self-developed, standardized protocol until the tobacco product was smoked down to 8 mm distance from the tipping paper of the filter. Results: Mean concentration (Cmean) and area under the curve (AUC) in a plot of PM2.5 against time were measured, and compared. CmeanPM2.5 were found to be 518 μg/m3 for 3R4F cigarettes, 576 μg/m3 for L&M “without additives” (“red”), 448 μg/m3 for L&M “blue label”, 547 μg/m3 for L&M “red label”, and 755 μg/m3 for L&M filtered cigarillos (“red”). AUCPM2.5-values were 208,214 μg/m3·s for 3R4F reference cigarettes, 204,629 μg/m3·s for L&M “without additives” (“red”), 152,718 μg/m3·s for L&M “blue label”, 238,098 μg/m3·s for L&M “red label” and 796,909 μg/m3·s for L&M filtered cigarillos (“red”). Conclusion: Considering the large and significant differences in particulate matter emissions between cigarettes and cigarillos, we think that a favorable taxation of cigarillos is not justifiable. PMID:26258782

Catecholamine transport in isolated lung parenchyma of pig

PubMed Central

Goldie, Roy G.; Paterson, James W.

1982-01-01

1 Lung parenchyma strips of the pig incubated at 37°C with [3H]-(-)-noradrenaline ([3H]-NA) or [3H]-(±)-isoprenaline ([3H]-Iso), accumulated radioactivity via saturable, high affinity uptake processes. Apparent saturation constants (Km) for [3H]-NA and [3H]-Iso were 1.34 × 10-6 M and 1.63 × 10-6 M respectively, while apparent transport maxima (Vmax) were 4.86 and 1.63 × 10-9 mol min-1 g-1 respectively. 2 Cellular accumulation of radioactivity from radiolabelled catecholamines was greatly reduced by lowering the temperature to 7°C, pretreatment with ouabain (100 μM), phentolamine (15 μM) or phenoxybenzamine (80 μM). However, accumulation of radioactivity derived from (3H]-NA was inhibited selectively by cocaine (10 μM) and desipramine (1 μM), while normetanephrine (80 μM) and 3-O-methylisoprenaline (50 μM) caused much greater reductions in cellular radioactivity from [3H]-Iso than from (3H]-NA. Taken together with information from kinetic studies, the results indicate that these amines are transported by separate uptake processes. 3 Cocaine (50 μM) which selectively reduced [3H]-NA transport, had no significant effect on the sensitivity (EC50) of isolated parenchyma lung strips of the pig to the contractile effects of cumulative concentrations of NA. The catechol-O-methyl transferase (COMT) inhibitor, U-0521 (60 μM), also failed to alter the potency of NA, while normetanephrine (80 μM) caused a 2 fold decrease in potency. 4 Phentolamine (15 μM), which reduced the cellular accumulation of radioactivity derived from [3H]-Iso by 64%, caused a small potentiation of Iso-induced relaxations of porcine lung strips. Normetanephrine (80 μM) and 3-O-methylisoprenaline (50 μM), which also depressed the accumulation of cellular radioactivity from [3H]-Iso by > 50%, caused rightward shifts in Iso concentration-effect curves as a result of β-adrenoceptor blockade. In sharp contrast, cortisol (80 μM) and U-0521 (60 μM), which caused smaller reductions in the cellular accumulation of radioactivity derived from [3H]-Iso, both caused an approximately 9 fold potentiation of responses to Iso in isolated lung strips. 5 The results indicate that the major sites of uptake and metabolism of NA in porcine parenchyma strip are remote from α-adrenoceptors mediating NA-induced contraction. Similarly, some major sites of uptake of Iso are remote from β-adrenoceptors mediating Iso-induced relaxation. However, β-adrenoceptors are apparently in close proximity to a compartment containing COMT activity. PMID:7104521

Cosmology from quantum potential in a system of oscillating branes

NASA Astrophysics Data System (ADS)

Sepehri, Alireza

2016-11-01

Recently, some authors proposed a new mechanism which gets rid of the Big Bang singularity and shows that the age of the universe is infinite. In this paper, we will confirm their results and predict that the universe may expand and contract many N fundamental strings decay to N M0-anti-M0-branes. Then, M0-branes join each other and build a M8-anti-M8 system. This system is unstable, broken and two anti-M4-branes, a compactified M4-brane, a M3-brane in addition to one M0-brane are produced. The M3-brane wraps around the compactified M4-brane and both of them oscillate between two anti-M4-branes. Our universe is located on the M3-brane and interacts with other branes by exchanging the M0-brane and some scalars in transverse directions. By wrapping of M3-brane, the contraction epoch of universe starts and some higher order of derivatives of scalar fields in the relevant action of branes are produced which are responsible for generating the generalized uncertainty principle (GUP). By oscillating the compactified M4-M3-brane and approaching one of anti-M4-branes, one end of M3-brane glues to the anti-M4-brane and other end remains sticking and wrapping around M4-brane. Then, by getting away of the M4-M3 system, M4 rolls, wrapped M3 opens and expansion epoch of universe begins. By closing the M4 to anti-M4, the mass of some scalars become negative and they make a transition to tachyonic phase. To remove these states, M4 rebounds, rolls and M3 wraps around it again. At this stage, expansion branch ends and universe enters a contraction epoch again. This process is repeated many times and universe expands and contracts due to oscillation of branes. We obtain the scale factor of universe in this system and find that its values only at t →-∞ shrinks to zero. Thus, in our method, the Big Bang is replaced by the fundamental string and the age of universe is predicted to be infinite. Also, when tachyonic states disappear at the beginning of expansion branch, some extra energy is produced and leads to an increase in the velocity of opening of M3. In these conditions, our universe, which is located on this brane, expands very fast and experiences an inflation epoch. Finally, by reducing the fields in 11-dimensional M-theory to the fields in four-dimensional universe, we show that our theory matches with quantum field theory prescriptions.

Inositol phosphates influence the membrane bound Ca/sup 2 +//Mg/sup 2 +/ stimulated ATPase from human erythrocyte membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kester, M.; Ekholm, J.; Kumar, R.

1986-03-01

The modulation by exogenous inositol phosphates of the membrane Ca/sup 2 +//Mg/sup 2 +/ ATPase from saponin/EGTA lysed human erythrocytes was determined in a buffer (pH 7.6) containing histidine, 80 mM, MgCl/sub 2/, 3.3 mM, NaCl, 74 mM, KCl, 30 mM, Na/sub 2/ATP, 2.3 mM, ouabain, 0.83 mM, with variable amounts of CaCl/sub 2/ and EGTA. The ATPase assay was linear with time at 44/sup 0/C. The inositol phosphates were commercially obtained and were also prepared from /sup 32/P labeled rabbit platelet inositol phospholipids. Inositol triphosphate (IP/sub 3/) elevated the Ca/sup 2 +//Mg/sup 2 +/ ATPase activity over basal levelsmore » in a dose, time, and calcium dependent manner and were increased up to 85% of control values. Activities for the Na/sup +//K/sup +/-ATPase and a Mg/sup 2 +/ ATPase were not effected by IP/sub 3/. Ca/sup 2 +//Mg/sup 2 +/APTase activity with IP/sub 2/ or IP/sub 3/ could be synergistically elevated with calmodulin addition. The activation of the ATPase with IP/sub 3/ was calcium dependent in a range from .001 to .02 mM. The apparent Km and Vmax values were determined for IP/sub 3/ stimulated Ca/sup 2 +//Mg/sup 2 +/ ATPase.« less

Variation of M3 muscarinic receptor expression in different prostate tissues and its significance.

PubMed

Song, Wei; Yuan, Mingzhen; Zhao, Shengtian

2009-08-01

To detect the expression of the muscarinic receptor (M receptor) in different prostate tissues and analyze the role of its subtype in prostatic oncogenesis. Thirty-six cases of normal prostate and benign prostatic hyperplasia, and 8 cases of prostatic tumor, were used in this study from the Shandong University, Shandong, China, between 2003-2006. The protein expressions of M1, M2, and M3 receptors in each group were determined by Western-blotting. The gene expressions of the M3 receptor and vascular endothelial growth factors (VEGF) in each group were determined by reverse transcriptase-polymerase chain reaction. The protein and gene expressions of the M3 receptor in the prostatic carcinoma group were higher than that of benign prostatic hyperplasia group (p=0.0001) and normal prostate group (p=0.0001). The M3 receptor and VEGF showed positive straight-line correlations of gene expressions with the 3 groups (r=0.4999, p=0.0001). The M3 receptor may have a close relationship with prostatic oncogenesis.

K(m, n) equations with fifth order symmetries and their integrability

NASA Astrophysics Data System (ADS)

Tian, Kai

2018-03-01

For K(m, n) equation ut =Dx3(un) + αDx(um) , all non-degenerate (n ≠ 0) cases admitting fifth order symmetries are identified, including K(m1, 1), K(m2 , - 1 / 2) and K(m3 , - 2) , where m1 = 0 , 1 , 2 , 3 , m2 = - 1 / 2 , 0 , 1 , 3 / 2 and m3 = - 2 , - 1 , 0 , 1 . For five less studied cases, namely K(0 , - 2) , K(- 1 , - 2) , K(- 2 , - 2) , K(- 1 / 2 , - 1 / 2) and K(3 / 2 , - 1 / 2) , bi-Hamiltonian structures are established through their invertible links with some famous integrable equations. Hence, all cases, having fifth order symmetries, of K(m, n) equation are integrable in the bi-Hamiltonian sense. As an interesting observation, their Hamiltonian operators are linearly combinations of Dx, Dx3 , uDx +Dx u and Dx u Dx-1uDx, basic ingredients in the bi-Hamiltonian theory of Korteweg-de Vries and modified Korteweg-de Vries equations.

The insect repellent N,N-diethyl-m-toluamide (DEET) induces angiogenesis via allosteric modulation of the M3 muscarinic receptor in endothelial cells.

PubMed

Legeay, Samuel; Clere, Nicolas; Hilairet, Grégory; Do, Quoc-Tuan; Bernard, Philippe; Quignard, Jean-François; Apaire-Marchais, Véronique; Lapied, Bruno; Faure, Sébastien

2016-06-27

The insect repellent N,N-diethyl-m-toluamide (DEET) has been reported to inhibit AChE (acetylcholinesterase) and to possess potential carcinogenic properties with excessive vascularization. In the present paper, we demonstrate that DEET specifically stimulates endothelial cells that promote angiogenesis which increases tumor growth. DEET activates cellular processes that lead to angiogenesis including proliferation, migration and adhesion. This is associated with an enhancement of NO production and VEGF expression in endothelial cells. M3 silencing or the use of a pharmacological M3 inhibitor abrogates all of these effects which reveals that DEET-induced angiogenesis is M3 sensitive. The experiments involving calcium signals in both endothelial and HEK cells overexpressing M3 receptors, as well as binding and docking studies demonstrate that DEET acts as an allosteric modulator of the M3 receptor. In addition, DEET inhibited AChE which increased acetylcholine bioavailability and binding to M3 receptors and also strengthened proangiogenic effects by an allosteric modulation.

Macrocyclic triamine derived glucose analogues for 99m Tc(CO)3 labeling: synthesis and biological evaluation as potential tumor-imaging agents.

PubMed

Liu, Teli; Gan, Qianqian; Zhang, Junbo

2017-02-01

[ 99m Tc(CO) 3 (H 2 O) 3 ] + has attracted great attention among 99m Tc-labeling techniques, due to its ease of preparation, readily substituted water molecules of the precursor fac-[ 99m Tc(CO) 3 (H 2 O) 3 ] + by a variety of functional groups, small size and inertness. Bifunctional chelator based on a macrocyclic polyamine framework shows easy complexation with [ 99m Tc(CO) 3 (H 2 O) 3 ] + to produce stable complex. In this study, two novel 1, 5, 9-triazacyclododecane derivatives containing a glucose group (6 and 7) were successfully synthesized by reacting different glucose-azides with alkyne-[12]aneN 3 via the so-called click chemistry and radiolabeled with [ 99m Tc(CO) 3 (H 2 O) 3 ] + to form 99m Tc(CO) 3 -6 (C-1-substituted complex) and 99m Tc(CO) 3 -7 (C-2-substituted complex) in high yields. The complexes were stable in vitro over 6 h when incubated in saline at room temperature and in mouse serum at 37 °C. The partition coefficient results showed that they were hydrophilic. The biodistribution studies in Kunming mice bearing S 180 tumor showed both complexes showed accumulation in the tumor. Between them, 99m Tc(CO) 3 -7 had the advantages of much higher tumor uptake and tumor/muscle ratio. Compared with other reported 99m Tc-radiolabeled glucose derivatives, 99m Tc(CO) 3 -7 also showed a higher tumor uptake and tumor/muscle ratio, suggesting it would be a potential candidate for further development as a tumor-imaging agent. © 2017 John Wiley & Sons A/S.

Seasonal variations and size distributions of water-soluble ions of atmospheric particulate matter at Shigatse, Tibetan Plateau.

PubMed

Yang, Yongjie; Zhou, Rui; Yan, Yan; Yu, Yue; Liu, Junqing; Di, Yi'an; Du, Zhenyu; Wu, Dan

2016-02-01

Size-segregated atmospheric particulate matter (PM) samples were collected from July 2012 to September 2013 at Shigatse, high-altitude (3836 m above sea level) site on the south Tibetan Plateau (TP); objectives were to determine the characteristics and size distribution of water-soluble ions (WSIs). Eight major WSIs (Na(+), K(+), Mg(2+), Ca(2+), NH4(+), Cl(-), SO4(2-), and NO3(-)) were detected by ion chromatography. The total concentrations of WSIs were 6370 ± 1916 ng m(-3) in dry season (October - December, January - April), and 5261 ± 769 ng/m(3) during wet phase (May - September). The contribution of K(+) (130 ng m(-3)), Cl(-) (2035 ng m(-3)), SO4(2-) (1176 ng m(-3)), and NO3(-) (706 ng m(-3))(-)were significantly enhanced in dry season, and that of Na(+) (455 ng m(-3)), Mg(2+)(65.4 ng m(-3)), Ca(2+)(1034 ng m(-3)), and NH4(+) (1948 ng m(-3)) were significantly enhanced during wet phase. Mg(2+) and Ca(2+) were concentrated in the coarse mode, and the other ions concentrated in fine mode and coarse mode during two seasons. The correlation coefficients between K(+) and NH4(+), Cl(-), SO4(2-) and NO3(-) were 0.58 (P < 0.01), 0.40 (P < 0.05), 0.82 (P < 0.01) and 0.69 (P < 0.01), indicating their dominant contribution from biomass burning in dry season. The significant correlation between NH4(+) and HCO3(-) which were calculated by ion balance (r = 0.89, P < 0.01), suggesting the source from nitrogen fertilizers during wet phase. Copyright © 2015 Elsevier Ltd. All rights reserved.

Invited Article: In situ comparison of passive radon-thoron discriminative monitors at subsurface workplaces in Hungary

NASA Astrophysics Data System (ADS)

Kávási, Norbert; Vigh, Tamás; Németh, Csaba; Ishikawa, Tetsuo; Omori, Yasutaka; Janik, Miroslaw; Yonehara, Hidenori

2014-02-01

During a one-year long measurement period, radon and thoron data obtained by two different passive radon-thoron discriminative monitors were compared at subsurface workplaces in Hungary, such as mines (bauxite and manganese ore) and caves (medical and touristic). These workplaces have special environmental conditions, such as, stable and high relative humidity (100%), relatively stable temperature (12°C-21°C), low or high wind speed (max. 2.4 m s-1) and low or elevated aerosol concentration (130-60 000 particles m-3). The measured radon and thoron concentrations fluctuated in a wide range among the different workplaces. The respective annual average radon concentrations and their standard deviations (in brackets) measured by the passive radon-thoron discriminative monitor with cellulose filter (CF) and the passive radon-thoron discriminative monitor with sponge filter (SF) were: 350(321) Bq m-3 and 550(497) Bq m-3 in the bauxite mine; 887(604) Bq m-3 and 1258(788) Bq m-3 in the manganese ore mine; 2510(2341) Bq m-3 and 3403(3075) Bq m-3 in the medical cave (Hospital Cave of Tapolca); and 6239(2057) Bq m-3 and 8512(1955) Bq m-3 in the touristic cave (Lake Cave of Tapolca). The respective average thoron concentrations and their standard deviation (in brackets) measured by CF and SF monitors were: 154(210) Bq m-3 and 161(148) Bq m-3 in the bauxite mine; 187(191) Bq m-3 and 117(147) Bq m-3 in the manganese-ore mine; 360(524) Bq m-3 and 371(789) Bq m-3 in the medical cave (Hospital Cave of Tapolca); and 1420(1184) Bq m-3 and 1462(3655) Bq m-3 in the touristic cave (Lake Cave of Tapolca). Under these circumstances, comparison of the radon data for the SF and CF monitors showed the former were consistently 51% higher in the bauxite mine, 38% higher in the manganese ore mine, and 34% higher in the caves. Consequently, correction is required on previously obtained radon data acquired by CF monitors at subsurface workplaces to gain comparable data for SF monitors. In the case of thoron, the data were unreliable and no significant tendency was seen during the comparison therefore comparison of previously obtained thoron data acquired by either CF or SF is doubtful. There was probable influence by relative humidity on the detection response; however, the effects of the high wind speed and elevated aerosol concentration could not be excluded. The results of this study call attention to the importance of calibration under extreme environmental conditions and the need for using reliable radon-thoron monitors for subsurface workplaces.

Sucrose dependent mineral phosphate solubilization in Enterobacter asburiae PSI3 by heterologous overexpression of periplasmic invertases.

PubMed

Kumar, Chanchal; Wagh, Jitendra; Archana, G; Naresh Kumar, G

2016-12-01

Enterobacter asburiae PSI3 solubilizes mineral phosphates in the presence of glucose by the secretion of gluconic acid generated by the action of a periplasmic pyrroloquinoline quinone dependent glucose dehydrogenase. In order to achieve mineral phosphate solubilization phenotype in the presence of sucrose, plasmids pCNK4 and pCNK5 containing genes encoding the invertase enzyme of Zymomonas mobilis (invB) and of Saccharomyces cerevisiae (suc2) under constitutive promoters were constructed with malE signal sequence (in case of invB alone as the suc2 is secreted natively). When introduced into E. asburiae PSI3, E. a. (pCNK4) and E. a. (pCNK5) transformants secreted 21.65 ± 0.94 and 22 ± 1.3 mM gluconic acid, respectively, in the presence of 75 mM sucrose and they also solubilized 180 ± 4.3 and 438 ± 7.3 µM P from the rock phosphate. In the presence of a mixture of 50 mM sucrose and 25 mM glucose, E. a. (pCNK5) secreted 34 ± 2.3 mM gluconic acid and released 479 ± 8.1 µM P. Moreover, in the presence of a mixture of eight sugars (10 mM each) in the medium, E. a. (pCNK5) released 414 ± 5.3 µM P in the buffered medium. Thus, this study demonstrates incorporation of periplasmic invertase imparted P solubilization ability to E. asburiae PSI3 in the presence of sucrose and mixture of sugars.

Aldehyde measurements in indoor environments in Strasbourg (France)

NASA Astrophysics Data System (ADS)

Marchand, C.; Bulliot, B.; Le Calvé, S.; Mirabel, Ph.

Formaldehyde and acetaldehyde concentrations have been measured in indoor environments of various public spaces (railway station, airport, shopping center, libraries, underground parking garage, etc.) of Strasbourg area (east of France). In addition, formaldehyde, acetaldehyde propionaldehyde and hexanal concentrations have been measured in 22 private homes in the same area. In most of the sampling sites, indoor and outdoor formaldehyde and acetaldehyde concentrations were measured simultaneously. Gaseous aldehydes levels were quantified by a conventional DNHP-derivatization method followed by liquid chromatography coupled to UV detection. Outdoor formaldehyde and acetaldehyde concentrations were both in the range 1-10 μg m -3, the highest values being measured at the airport and railway station. Indoor concentrations were strongly dependant upon the sampling sites. In homes, the average concentrations were 37 μg m -3 (living rooms) and 46 μg m -3 (bedrooms) for formaldehyde, 15 μg m -3 (living rooms) and 18 μg m -3 (bedrooms) for acetaldehyde, 1.2 μg m -3 (living rooms) and 1.6 μg m -3 (bedrooms) for propionaldehyde, 9 μg m -3 (living rooms) and 10 μg m -3 (bedrooms) for hexanal. However, concentrations as high as 123, 80 and 47 μg m -3 have been found for formaldehyde, acetaldehyde and hexanal respectively. In public spaces, the highest formaldehyde concentration (62 μg m -3) was found in a library and the highest concentration of acetaldehyde (26 μg m -3) in the hall of a shopping center. Additional measurements of formaldehyde and acetaldehyde were made inside a car both at rest or in a fluid or heavy traffic as well as in a room where cigarettes were smoked. Our data have been discussed and compared with those of previous studies.

Effect of Layering Methods, Composite Type, and Flowable Liner on the Polymerization Shrinkage Stress of Light Cured Dental Composites

DTIC Science & Technology

2011-08-01

composite (Z350 flowable: 3M ESPE), and a silorane-based composite (P90: 3M ESPE). Scotchbond multipurpose adhesive ( 3M ESPE) was applied prior to...syringe. Composites used for filling the cavities were a methacrylate-based universal hybrid composite (Z250: 3M ESPE, St. Paul, MN, USA), a flowable... adhesive was light cured for 10 s using a LED light curing unit (S10: 3M ESPE), and the light intensity was 1200 mW/cm 2 . An acrylic case with

Interaction between PNPLA3 I148M variant and age at infection in determining fibrosis progression in chronic hepatitis C.

PubMed

De Nicola, Stella; Dongiovanni, Paola; Aghemo, Alessio; Cheroni, Cristina; D'Ambrosio, Roberta; Pedrazzini, Michele; Marabita, Francesco; Donnici, Lorena; Maggioni, Marco; Fargion, Silvia; Colombo, Massimo; De Francesco, Raffaele; Valenti, Luca

2014-01-01

The PNPLA3 I148M sequence variant favors hepatic lipid accumulation and confers susceptibility to hepatic fibrosis and hepatocellular carcinoma. The aim of this study was to estimate the effect size of homozygosity for the PNPLA3 I148M variant (148M/M) on the fibrosis progression rate (FPR) and the interaction with age at infection in chronic hepatitis C (CHC). FPR was estimated in a prospective cohort of 247 CHC patients without alcohol intake and diabetes, with careful estimation of age at infection and determination of fibrosis stage by Ishak score. Older age at infection was the strongest determinant of FPR (p<0.0001). PNPLA3 148M/M was associated with faster FPR in individuals infected at older age (above the median, 21 years; -0.64±0.2, n = 8 vs. -0.95±0.3, n = 166 log10 FPR respectively; p = 0.001; confirmed for lower age thresholds, p<0.05), but not in those infected at younger age (p = ns). The negative impact of PNPLA3 148M/M on fibrosis progression was more marked in subjects at risk of altered hepatic lipid metabolism (those with grade 2-3 steatosis, genotype 3, and overweight; p<0.05). At multivariate analysis, PNPLA3 148M/M was associated with FPR (incremental effect 0.08±0.03 log10 fibrosis unit per year; p = 0.022), independently of several confounders, and there was a significant interaction between 148M/M and older age at infection (p = 0.025). The association between 148M/M and FPR remained significant even after adjustment for steatosis severity (p = 0.032). We observed an interaction between homozygosity for the PNPLA3 I148M variant and age at infection in determining fibrosis progression in CHC patients.

Interaction between PNPLA3 I148M Variant and Age at Infection in Determining Fibrosis Progression in Chronic Hepatitis C

PubMed Central

Aghemo, Alessio; Cheroni, Cristina; D'Ambrosio, Roberta; Pedrazzini, Michele; Marabita, Francesco; Donnici, Lorena; Maggioni, Marco; Fargion, Silvia; Colombo, Massimo; De Francesco, Raffaele; Valenti, Luca

2014-01-01

Background and Aims The PNPLA3 I148M sequence variant favors hepatic lipid accumulation and confers susceptibility to hepatic fibrosis and hepatocellular carcinoma. The aim of this study was to estimate the effect size of homozygosity for the PNPLA3 I148M variant (148M/M) on the fibrosis progression rate (FPR) and the interaction with age at infection in chronic hepatitis C (CHC). Methods FPR was estimated in a prospective cohort of 247 CHC patients without alcohol intake and diabetes, with careful estimation of age at infection and determination of fibrosis stage by Ishak score. Results Older age at infection was the strongest determinant of FPR (p<0.0001). PNPLA3 148M/M was associated with faster FPR in individuals infected at older age (above the median, 21 years; −0.64±0.2, n = 8 vs. −0.95±0.3, n = 166 log10 FPR respectively; p = 0.001; confirmed for lower age thresholds, p<0.05), but not in those infected at younger age (p = ns). The negative impact of PNPLA3 148M/M on fibrosis progression was more marked in subjects at risk of altered hepatic lipid metabolism (those with grade 2–3 steatosis, genotype 3, and overweight; p<0.05). At multivariate analysis, PNPLA3 148M/M was associated with FPR (incremental effect 0.08±0.03 log10 fibrosis unit per year; p = 0.022), independently of several confounders, and there was a significant interaction between 148M/M and older age at infection (p = 0.025). The association between 148M/M and FPR remained significant even after adjustment for steatosis severity (p = 0.032). Conclusions We observed an interaction between homozygosity for the PNPLA3 I148M variant and age at infection in determining fibrosis progression in CHC patients. PMID:25171251

Exposure to bioaerosols in the selected agricultural facilities of the Ukraine and Poland - a review.

PubMed

Tsapko, Valentin G; Chudnovets, Alla J; Sterenbogen, Marina J; Papach, Vladimir V; Dutkiewicz, Jacek; Skórska, Czesława; Krysińska-Traczyk, Ewa; Golec, Marcin

2011-01-01

The aim of this work was to review the studies on bioaerosols which were carried out in the years 1972-2009 in following branches of agricultural industry in the Ukraine and Poland: animal farms for cows and pigs, animal feed facilities, production of biofuel from rape, herb farms and herb processing facilities. In all facilities were determined: concentration of dust and microorganisms in the air and species composition of microflora. Moreover, in Polish animal farms, herb farms and herb processing facilities, as well as in the Ukrainian animal feed facilities, was determined the concentration of bacterial endotoxin in the air. Dust concentrations in animal farms located in the Ukraine and Poland ranged from 6-200 mg/m(3) and from 0.25-14.05 mg/m(3), respectively, while in animal feed facilities they ranged from 35-306 mg/m(3) and from 3.8-405 mg/m(3), respectively. Dust concentrations in the facilities producing biofuel from rape in the Ukraine were in the range 3.6-28 mg/m(3), whereas on herb farms and in herb processing facilities in Poland they were in the range 0.8- 1,319.6 mg/m(3), and 2.2-946 mg/m(3), respectively. The determined values exceeded in most cases the maximal acceptable concentration (MAC) which in the Ukraine and Poland is equal to 4 mg/m(3). The concentrations of microorganisms on animal farms located in the Ukraine and Poland ranged from 5.5 x 10(4)- 1.9 x 10(7) cfu/m(3) and from 4.7 x 10(4)-1.5 x 10(6) cfu/m(3), respectively, while in animal feed facilities they ranged from 2.7 x 10(4)-2.6 x 10(9) cfu/m(3) and from 1.7 x 10(3)-2.0 x 10(6) cfu/m(3), respectively. Concentrations of microorganisms in the facilities producing biofuel from rape in the Ukraine were in the range 1.5 x 10(3)-5.7 x 10(6) cfu/m(3), whereas on herb farms and in herb processing facilities in Poland they were in the ranges of 8.8 x 10(2)-8.0 x 10(6) cfu/m(3), and 9.7 x 10(3)-6.3 x 10(5) cfu/m(3), respectively. The determined values exceeded in most cases the maximal acceptable concentration (MAC) which in the Ukraine is equal to 5.0 x 10(4) cfu/m(3). The concentrations of endotoxin in Polish animal houses were in the range 0.00125-75.0 ug/m(3), whereas on herb farms and herb processing facilities they were in the ranges of 0.0045- 2,448.8 ug/m(3) and 0.2-681.0 ug/m(3), respectively, and in the Ukrainian animal feed facilities were within the range 0.008-240.0 ug/m(3). They exceeded in most cases the level of 0.2 ug/m(3) proposed as a threshold. In the air microflora of examined facilities prevailed Gram-positive bacteria (corynebacteria, cocci, spore-forming bacilli, actinomycetes) of which some (Arthrobacter spp., thermophilic actinomycetes) could be a cause of allergic alveolitis (hypersensitivity pneumonitis). Among Gram-negative bacteria isolated from the air of agricultural settings dominated the epiphytic species Pantoea agglomerans, possessing potent allergenic and endotoxic properties. Fungi were abundant in the air of the Ukrainian agricultural settings and comprised species able to produce harmful mycotoxins. In conclusion, the airborne biological factors in stated concentrations may exert harmful effects on the state of the health of exposed workers. Formation of the bioaerosol depends on the specificity of the setting, kind of technological operations, degree of mechanization, properties of processed materials, temperature and humidity, and concentration of dust in the air.

Evolution of size-segregated aerosol mass concentration during the Antarctic summer at Northern Foothills, Victoria Land

NASA Astrophysics Data System (ADS)

Illuminati, Silvia; Bau, Sébastien; Annibaldi, Anna; Mantini, Caterina; Libani, Giulia; Truzzi, Cristina; Scarponi, Giuseppe

2016-01-01

Within the framework of the Italian National Programm for Antarctic Research (PNRA), the first direct gravimetric measurements of size-segregated aerosol fractions were carried out at Faraglione Camp, ˜3-km far from the Italian station "M. Zucchelli" (Terra Nova Bay, Ross Sea), during the 2014-2015 austral summer. A six-stage high-volume cascade impactor with size classes between 10 μm and 0.49 μm, and, in parallel, for comparison purposes, a PM10 high-volume sampler (50% cut-off aerodynamic diameter of 10 μm) were used. A 10-day sampling strategy was adopted. Aerosol mass measurements were carried out before and after exposure by using a microbalance specifically designed for the filter weight and placed inside a glove bag in order to maintain stable temperature and humidity conditions during weighing sessions. Measured atmospheric concentrations (referred to the "actual air conditions" of mean temperature of 268 K and mean pressure of 975 hPa) of size-segregated aerosol fractions showed the following values, given as size range, means (interquartile range): Dp < 0.49 μm, 0.33 (0.26-0.34) μg m-3; 0.49-0.95 μm, 0.20 (0.19-0.24) μg m-3; 0.95-1.5 μm, 0.16 (0.13-0.21) μg m-3; 1.5-3.0 μm 0.075 (0.05-0.11) μg m-3; 3.0-7.2 μm 0.12 (0.02-0.19) μg m-3; 7.2-10 μm 0.06 (0.01-0.03) μg m-3. The average mass concentration of the total PM10 at Faraglione Camp for the entire sampling period was 0.92 (0.67-1.1) μg m-3. Although a great variability, the aerosol mass concentration showed a tri-modal distribution, with an accumulation mode (in the range 0.1-1.0 μm) and two coarse modes (CM1 in the range 1.0-3.0 μm, and CM2 in the range 3.0-10 μm). From 50% to 90% of the PM10 mass comes from particles of a size smaller than 1.0 μm. The two coarse modes represented from ˜5% to ˜35% of the PM10, showing opposite seasonal trends (CM1 decreased while CM2 increased). During summer, PM10 mass concentration increased to a maximum of ˜1.6 μg m-3 at mid-December, while in January it decreased to values that are typical of November. Both accumulation and upper super-micron fractions showed a maximum in the same period contributing to the PM10 peak of mid-summer.

Customer exposure to MTBE, TAME, C6 alkyl methyl ethers, and benzene during gasoline refueling.

PubMed Central

Vainiotalo, S; Peltonen, Y; Ruonakangas, A; Pfäffli, P

1999-01-01

We studied customer exposure during refueling by collecting air samples from customers' breathing zone. The measurements were carried out during 4 days in summer 1996 at two Finnish self-service gasoline stations with "stage I" vapor recovery systems. The 95-RON (research octane number) gasoline contained approximately 2.7% methyl tert-butyl ether (MTBE), approximately 8.5% tert-amyl methyl ether (TAME), approximately 3.2% C6 alkyl methyl ethers (C6 AMEs), and 0.75% benzene. The individual exposure concentrations showed a wide log-normal distribution, with low exposures being the most frequent. In over 90% of the samples, the concentration of MTBE was higher (range <0.02-51 mg/m3) than that of TAME. The MTBE values were well below the short-term (15 min) threshold limits set for occupational exposure (250-360 mg/m3). At station A, the geometric mean concentrations in individual samples were 3.9 mg/m3 MTBE and 2. 2 mg/m3 TAME. The corresponding values at station B were 2.4 and 1.7 mg/m3, respectively. The average refueling (sampling) time was 63 sec at station A and 74 sec at station B. No statistically significant difference was observed in customer exposures between the two service stations. The overall geometric means (n = 167) for an adjusted 1-min refueling time were 3.3 mg/m3 MTBE and 1.9 mg/m3 TAME. Each day an integrated breathing zone sample was also collected, corresponding to an arithmetic mean of 20-21 refuelings. The overall arithmetic mean concentrations in the integrated samples (n = 8) were 0.90 mg/m3 for benzene and 0.56 mg/m3 for C6 AMEs calculated as a group. Mean MTBE concentrations in ambient air (a stationary point in the middle of the pump island) were 0.16 mg/m3 for station A and 0.07 mg/m3 for station B. The mean ambient concentrations of TAME, C6 AMEs, and benzene were 0.031 mg/m3, approximately 0.005 mg/m3, and approximately 0.01 mg/m3, respectively, at both stations. The mean wind speed was 1.4 m/sec and mean air temperature was 21 degreesC. Of the gasoline refueled during the study, 75% was 95 grade and 25% was 98/99 grade, with an oxygenate (MTBE) content of 12.2%. Images Figure 1 Figure 2 Figure 3 Figure 4 PMID:9924009

PKI-179: an orally efficacious dual phosphatidylinositol-3-kinase (PI3K)/mammalian target of rapamycin (mTOR) inhibitor.

PubMed

Venkatesan, Aranapakam M; Chen, Zecheng; dos Santos, Osvaldo; Dehnhardt, Christoph; Santos, Efren Delos; Ayral-Kaloustian, Semiramis; Mallon, Robert; Hollander, Irwin; Feldberg, Larry; Lucas, Judy; Yu, Ker; Chaudhary, Inder; Mansour, Tarek S

2010-10-01

A series of mono-morpholino 1,3,5-triazine derivatives (8a-8q) bearing a 3-oxa-8-azabicyclo[3.2.1]octane were prepared and evaluated for PI3-kinase/mTOR activity. Replacement of one of the bis-morpholines in lead compound 1 (PKI-587) with 3-oxa-8-azabicyclo[3.2.1]octane and reduction of the molecular weight yielded 8m (PKI-179), an orally efficacious dual PI3-kinase/mTOR inhibitor. The in vitro activity, in vivo efficacy, and PK properties of 8m are discussed. Copyright © 2010. Published by Elsevier Ltd.

Hydrogen-rich scandium compounds at high pressures

NASA Astrophysics Data System (ADS)

Abe, Kazutaka

2017-10-01

Scandium hydrides at high pressures have been investigated by using ab initio density functional calculations. Although the stable scandium hydride so far known to have the highest content rate of hydrogen is ScH3, other more hydrogen-rich compounds are found to be possible at high pressures. These are ScH4 in the I 4 /m m m structure above 160 GPa, ScH6 in the P 63/m m c structure from 135 to 265 GPa, and ScH6 in the I m 3 ¯m structure above 265 GPa. The three phases are all metallic, and the superconducting transition temperatures estimated from the extended McMillan equation are 67 K in the I 4 /m m m ScH4 at 195 GPa, 63 K in the P 63/m m c ScH6 at 145 GPa, and 130 K in the I m 3 ¯m ScH6 at 285 GPa. While the I 4 /m m m tetrahydride and the I m 3 ¯m hexahydride were similarly predicted for yttrium (another group-3 element), the P 63/m m c hexahydride is possible only for scandium. The smaller atomic size of scandium stabilizes the P 63/m m c structure, and other nearby d -block elements, whose atomic sizes are smaller or comparable, might be likewise capable of forming such polyhydrides.

Halophilic starch degrading bacteria isolated from Sambhar Lake, India, as potential anode catalyst in microbial fuel cell: A promising process for saline water treatment.

PubMed

Vijay, Ankisha; Arora, Shivam; Gupta, Sandeep; Chhabra, Meenu

2018-05-01

In this study, Microbial Fuel Cell (MFC) capable of treating saline starch water was developed. Sodium chloride (NaCl) concentrations ranging from 500 mM to 3000 mM were tested at the anode. Nitrate was used as an electron acceptor at the biocathode. The halophilic bacteria were isolated from Sambhar Lake, India. Results indicated successful removal of starch (1.83 kg/m 3 -d) and nitrate (0.13 kg/m 3 -d NO 3 - -N) with concomitant power output of 207.05 mW/m 2 at 1000 mM NaCl concentration. An increase in power density from 71.06 mW/m 2 to 207.05 mW/m 2 (2.92 folds) was observed when NaCl concentration was increased from 500 mM to 1000 mM. A decline in power density was observed when the salt concentrations >1000 mM were used. Concentration of 3000 mM supported power output as well as the highest starch degradation (3.2 kg/m 3 -d) and amylase activity of 2.26 IU/ml. The halophilic exoelectrogens were isolated and identified. The present study demonstrates the utility of MFC for degrading starch in saline water. Copyright © 2018 Elsevier Ltd. All rights reserved.

Enzymatic Browning in Sugar Beet Leaves (Beta vulgaris L.): Influence of Caffeic Acid Derivatives, Oxidative Coupling, and Coupled Oxidation.

PubMed

Vissers, Anne; Kiskini, Alexandra; Hilgers, Roelant; Marinea, Marina; Wierenga, Peter Alexander; Gruppen, Harry; Vincken, Jean-Paul

2017-06-21

Sugar beet (Beta vulgaris L.) leaves of 8 month (8 m ) plants showed more enzymatic browning than those of 3 month (3 m ). Total phenolic content increased from 4.6 to 9.4 mg/g FW in 3 m and 8 m , respectively, quantitated by reverse-phase-ultrahigh-performance liquid chromatography-ultraviolet-mass spectrometry (RP-UHPLC-UV-MS). The PPO activity was 6.7 times higher in extracts from 8 m than from 3 m leaves. Substrate content increased from 0.53 to 2.45 mg/g FW in 3 m and 8 m , respectively, of which caffeic acid glycosyl esters were most important, increasing 10-fold with age. Caffeic acid glycosides and vitexin derivatives were no substrates. In 3 m and 8 m, nonsubstrate-to-substrate ratios were 8:1 and 3:1, respectively. A model system showed browning at 3:1 ratio due to formation of products with extensive conjugated systems through oxidative coupling and coupled oxidation. The 8:1 ratio did not turn brown as oxidative coupling occurred without much coupled oxidation. We postulate that differences in nonsubstrate-to-substrate ratio and therewith extent of coupled oxidation explain browning.

Enzymatic Browning in Sugar Beet Leaves (Beta vulgaris L.): Influence of Caffeic Acid Derivatives, Oxidative Coupling, and Coupled Oxidation

PubMed Central

2017-01-01

Sugar beet (Beta vulgaris L.) leaves of 8 month (8m) plants showed more enzymatic browning than those of 3 month (3m). Total phenolic content increased from 4.6 to 9.4 mg/g FW in 3m and 8m, respectively, quantitated by reverse-phase-ultrahigh-performance liquid chromatography–ultraviolet-mass spectrometry (RP-UHPLC–UV-MS). The PPO activity was 6.7 times higher in extracts from 8m than from 3m leaves. Substrate content increased from 0.53 to 2.45 mg/g FW in 3m and 8m, respectively, of which caffeic acid glycosyl esters were most important, increasing 10-fold with age. Caffeic acid glycosides and vitexin derivatives were no substrates. In 3m and 8m, nonsubstrate-to-substrate ratios were 8:1 and 3:1, respectively. A model system showed browning at 3:1 ratio due to formation of products with extensive conjugated systems through oxidative coupling and coupled oxidation. The 8:1 ratio did not turn brown as oxidative coupling occurred without much coupled oxidation. We postulate that differences in nonsubstrate-to-substrate ratio and therewith extent of coupled oxidation explain browning. PMID:28570816

A COMPARATIVE STUDY OF DIURNAL VARIATION OF RADON AND THORON CONCENTRATIONS IN INDOOR ENVIRONMENT.

PubMed

Pant, Preeti; Kandari, Tushar; Prasad, Mukesh; Ramola, R C

2016-10-01

The diurnal measurements of radon and thoron concentrations were performed in the indoor environment of Nuclear Research Laboratory, Badshahi Thaul, Tehri Garhwal, Uttarakhand, India by using AlphaGUARD, Portable Radon Monitor (SMART RnDuo) and RAD7. Using AlphaGUARD, the radon concentration was found to vary from 8 to 94 Bq m -3 with an average of 41.5±22.2 Bq m -3 Using Portable Radon Monitor (SMART RnDuo), the concentration was found to vary from 2 to 101 Bq m -3 with an average of 41.7±23.6 Bq m -3 , and with RAD7, the concentration was found to vary from 3 to 99 Bq m -3 with an average of 40±20.3 Bqm -3 While the thoron concentration using Portable Radon Monitor (SMART RnDuo) was found to vary from 4 to 65 Bq m -3 with an average of 17.3±12.9 Bqm -3 , and using RAD7, the concentration was found to vary from 5 to 90 Bq m -3 with an average of 29.8±17.3 Bq m -3 . © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Enhanced Reactant-Contaminant Contact through the Use of Persulfate In Situ Chemical Oxidation (ISCO)

DTIC Science & Technology

2011-02-01

cuprite [Cu2O], hematite [Fe2O3], ilmenite [FeTiO3], magnesite [MgCO3], malachite [Cu2(CO3)(OH)2], pyrite [FeS2], pyrolusite [MnO2], siderite [FeCO3...0.3 m2/g], malachite [3.65 ± 0.03 m2/g], pyrite [2.12 ± 0.01 m2/g], pyrolusite [1.39 ± 0.04 m2/g], siderite [6.8 ± 0.4 m2/g], willemite [1.8 ± 0.02 m2...0.4 0.6 0.8 1 0 10 20 30 40 50 60 Anatase Bauxite Calcite Cobaltite Control Cuprite Hematite Ilmenite Magnesite Malachite Pyrite Pyrolusite Siderite

The transfer of strength and power into the stroke biomechanics of young swimmers over a 34-week period.

PubMed

Morais, Jorge E; Silva, António J; Garrido, Nuno D; Marinho, Daniel A; Barbosa, Tiago M

2018-03-24

The purpose of this study was to learn the interplay between dry-land strength and conditioning, and stroke biomechanics in young swimmers, during a 34-week training programme. Twenty-seven swimmers (overall: 13.33 ± 0.85 years old; 11 boys: 13.5 ± 0.75 years old; 16 girls: 13.2 ± 0.92 years old) competing at regional- and national-level competitions were evaluated. The swimmers were submitted to a specific in-water and dry-land strength training over 34 weeks (and evaluated at three time points: pre-, mid-, and post-test; M1, M2, and M3, respectively). The 100-m freestyle performance was chosen as the main outcome (i.e. dependent variable). The arm span (AS; anthropometrics), throwing velocity (TV; strength), stroke length (SL), and stroke frequency (SF; kinematics) were selected as independent variables. There was a performance enhancement over time (M1 vs. M3: 68.72 ± 5.57 s, 66.23 ± 5.23 s; Δ = -3.77%; 95% CI: -3.98;-3.56) and an overall improvement of the remaining variables. At M1 and M2, all links between variables presented significant effects (p < .001), except the TV-SL and the TV-SF path. At M3, all links between variables presented significant effects (p ≤ .05). Between M1 and M3, the direct effect of the TV to the stroke biomechanics parameters (SL and SF) increased. The model predicted 89%, 88%, and 92% of the performance at M1, M2, and M3, respectively, with a reasonable adjustment (i.e. goodness-of-fit M1: χ 2 /df = 3.82; M2: χ 2 /df = 3.08; M3: χ 2 /df = 4.94). These findings show that strength and conditioning parameters have a direct effect on the stroke biomechanics, and the latter one on the swimming performance.

The NO donor DETA-NONOate reversibly activates an inward current in neurones and is not mediated by the released nitric oxide.

PubMed

Thompson, A J; Mander, P K; Brown, G C

2009-11-01

It has been previously shown that high levels of nitric oxide (NO), from NO donors, kill neurones, but the mechanisms are unclear. The effects of NO donors on the electrical properties of rat cultured cerebellar granule cells (CGC neurones) were investigated using the whole-cell patch-clamp technique. The NO donor (Z)-1-[2-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate (DETA-NONOate or NOC-18) caused a rapid, persistent, but fully reversible inward current that was associated with an increase in baseline noise and was concentration dependent (100 microM-10 mM). The response to 3 mM DETA-NONOate was completely inhibited by 1 mM gadolinium, but not by NO scavengers (1 mM haemoglobin or 1 mM PTIO) or glutamate receptor antagonists (10 microM MK-801 or 60 microM CNQX). Application of decomposed 3 mM DETA-NONOate or 3 mM nitrite had no effect. In contrast, the NO donor S-nitrosoglutathione (GSNO) caused a rapid, persistent, but fully reversible outward current that was also concentration dependent (1-10 mM). The 3 mM GSNO response was unaltered by NO scavengers, glutamate antagonists or gadolinium, but was mimicked by decomposed 3 mM GSNO and 3 mM oxidized glutathione. These results suggest that DETA-NONOate directly activates cation-selective channels, causing an inward current in CGCs. In contrast, GSNO causes an outward current in these cells. Some of the effects of these NO donors are independent of NO, and thus caution is required in interpreting results when using high concentrations of these compounds.

Isolation and characterization of rabbit anti-m3 2,2,7G antibodies.

PubMed Central

Luhrmann, R; Appel, B; Bringmann, P; Rinke, J; Reuter, R; Rothe, S; Bald, R

1982-01-01

Antibodies specific for intact 2,2,7-trimethylguanosine (m3 2,2,7G) were induced by immunization of rabbits with a nucleoside-human serum albumen (HSA) conjugate. Competition radioimmunoassay showed that the antibody distinguishes well between intact m3 2,2,7G and its alkali-hydrolysed form (m3 2,2,7G*). Antibody specificity is largely dependent on the presence of all three methyl groups in m3 2,2,7G: none of the less extensively methylated nucleosides m7G, m2G and m2 2,2G is able to compete efficiently with the homologous hapten. Little or no competition was observed with m1G, m1A, m6A, m5U and each of the four unmodified ribonucleosides. Binding studies with nucleoplasmic RNAs from Ehrlich ascites cells suggest that the antibody reacts specifically with the m3 2,2,7G-containing cap structure of the small nuclear U-RNAs (U-snRNAs). Thus the antibody should be a valuable tool for studying the role of the 5'-terminal regions of the U-snRNAs of eucaryotic cells. Images PMID:7155893

Synovitis biomarkers: ex vivo characterization of three biomarkers for identification of inflammatory osteoarthritis

PubMed Central

Kjelgaard-Petersen, Cecilie; Siebuhr, Anne Sofie; Christiansen, Thorbjørn; Ladel, Christoph; Karsdal, Morten; Bay-Jensen, Anne-Christine

2015-01-01

Abstract Objective: Characterize biomarkers measuring extracellular matrix turnover of inflamed osteoarthritis synovium. Methods: Human primary fibroblast-like synoviocytes and synovial membrane explants (SMEs) treated with various cytokines and growth factors were assessed by C1M, C3M, and acMMP3 in the conditioned medium. Results: TNFα significantly increased C1M up to seven-fold (p = 0.0002), C3M up to 24-fold (p = 0.0011), and acMMP3 up to 14-fold (p < 0.0001) in SMEs. IL-1β also significantly increased C1M up to five-fold (p = 0.00094), C3M four-fold (p = 0.007), and acMMP3 18-fold (p < 0.0001) in SMEs. Conclusion: The biomarkers C1M, C3M, and acMMP-3 were synovitis biomarkers ex vivo and provide a translational tool together with the SME model. PMID:26863055

Pretreatment of shale gas drilling flowback fluid (SGDF) by the microscale Fe0/persulfate/O3 process (mFe0/PS/O3).

PubMed

Zhang, Heng; Xiong, Zhaokun; Ji, Fangzhou; Lai, Bo; Yang, Ping

2017-06-01

Shale gas drilling flowback fluid (SGDF) generated during shale gas extraction is of great concern due to its high total dissolved solid, radioactive elements and organic matter. To remove the toxic and refractory pollutants in SGDF and improve its biodegradability, a microsacle Fe 0 /Persulfate/O 3 process (mFe 0 /PS/O 3 ) was developed to pretreat this wastewater obtained from a shale gas well in southwestern China. First, effects of mFe 0 dosage, O 3 flow rate, PS dosage, pH values on the treatment efficiency of mFe 0 /PS/O 3 process were investigated through single-factor experiments. Afterward, the optimal conditions (i.e., pH = 6.7, mFe 0 dosage = 6.74 g/L, PS = 16.89 mmol/L, O 3 flow rate = 0.73 L/min) were obtained by using response surface methodology (RSM). Under the optimal conditions, high COD removal (75.3%) and BOD 5 /COD ratio (0.49) were obtained after 120 min treatment. Moreover, compared with control experiments (i.e., mFe 0 , O 3 , PS, mFe 0 /O 3 , mFe 0 /PS, O 3 /PS), mFe 0 /PS/O 3 system exerted better performance for pollutants removal in SGDF due to strong synergistic effect between mFe 0 , PS and O 3 . In addition, the decomposition or transformation of the organic pollutants in SGDF was analyzed by using GC-MS. Finally, the reaction mechanism of the mFe 0 /PS/O 3 process was proposed according to the analysis results of SEM-EDS and XRD. It can be concluded that high-efficient mFe 0 /PS/O 3 process was mainly resulted from the combination effect of direct oxidation by ozone and persulfate, heterogeneous and homogeneous catalytic oxidation, Fenton-like reaction and adsorption. Therefore, mFe 0 /PS/O 3 process was proven to be an effective method for pretreatment of SGDF prior to biological treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Galectin-3 is a non-classic RNA binding protein that stabilizes the mucin MUC4 mRNA in the cytoplasm of cancer cells.

PubMed

Coppin, Lucie; Vincent, Audrey; Frénois, Frédéric; Duchêne, Belinda; Lahdaoui, Fatima; Stechly, Laurence; Renaud, Florence; Villenet, Céline; Van Seuningen, Isabelle; Leteurtre, Emmanuelle; Dion, Johann; Grandjean, Cyrille; Poirier, Françoise; Figeac, Martin; Delacour, Delphine; Porchet, Nicole; Pigny, Pascal

2017-03-06

Pancreatic cancer cells express high levels of MUC1, MUC4 and MUC16 mRNAs that encode membrane-bound mucins. These mRNAs share unusual features such as a long half-life. However, it remains unknown how mucin mRNA stability is regulated. Galectin-3 (Gal-3) is an endogenous lectin playing important biological functions in epithelial cells. Gal-3 is encoded by LGALS3 which is up-regulated in pancreatic cancer. Despite the absence of a RNA-recognition motif, Gal-3 interacts indirectly with pre-mRNAs in the nucleus and promotes constitutive splicing. However a broader role of Gal-3 in mRNA fate is unexplored. We report herein that Gal-3 increases MUC4 mRNA stability through an intermediate, hnRNP-L which binds to a conserved CA repeat element in the 3'UTR in a Gal-3 dependent manner and also controls Muc4 mRNA levels in epithelial tissues of Gal3 -/- mice. Gal-3 interacts with hnRNP-L in the cytoplasm, especially during cell mitosis, but only partly associates with protein markers of P-Bodies or Stress Granules. By RNA-IP plus RNA-seq analysis and imaging, we demonstrate that Gal-3 binds to mature spliced MUC4 mRNA in the perinuclear region, probably in hnRNP-L-containing RNA granules. Our findings highlight a new role for Gal-3 as a non-classic RNA-binding protein that regulates MUC4 mRNA post-transcriptionally.

Galectin-3 is a non-classic RNA binding protein that stabilizes the mucin MUC4 mRNA in the cytoplasm of cancer cells

PubMed Central

Coppin, Lucie; Vincent, Audrey; Frénois, Frédéric; Duchêne, Belinda; Lahdaoui, Fatima; Stechly, Laurence; Renaud, Florence; Villenet, Céline; Seuningen, Isabelle Van; Leteurtre, Emmanuelle; Dion, Johann; Grandjean, Cyrille; Poirier, Françoise; Figeac, Martin; Delacour, Delphine; Porchet, Nicole; Pigny, Pascal

2017-01-01

Pancreatic cancer cells express high levels of MUC1, MUC4 and MUC16 mRNAs that encode membrane-bound mucins. These mRNAs share unusual features such as a long half-life. However, it remains unknown how mucin mRNA stability is regulated. Galectin-3 (Gal-3) is an endogenous lectin playing important biological functions in epithelial cells. Gal-3 is encoded by LGALS3 which is up-regulated in pancreatic cancer. Despite the absence of a RNA-recognition motif, Gal-3 interacts indirectly with pre-mRNAs in the nucleus and promotes constitutive splicing. However a broader role of Gal-3 in mRNA fate is unexplored. We report herein that Gal-3 increases MUC4 mRNA stability through an intermediate, hnRNP-L which binds to a conserved CA repeat element in the 3′UTR in a Gal-3 dependent manner and also controls Muc4 mRNA levels in epithelial tissues of Gal3−/− mice. Gal-3 interacts with hnRNP-L in the cytoplasm, especially during cell mitosis, but only partly associates with protein markers of P-Bodies or Stress Granules. By RNA-IP plus RNA-seq analysis and imaging, we demonstrate that Gal-3 binds to mature spliced MUC4 mRNA in the perinuclear region, probably in hnRNP-L-containing RNA granules. Our findings highlight a new role for Gal-3 as a non-classic RNA-binding protein that regulates MUC4 mRNA post-transcriptionally. PMID:28262838

(99m)Tc(CO)3(NTA): a (99m)Tc renal tracer with pharmacokinetic properties comparable to those of (131)I-OIH in healthy volunteers.

PubMed

Taylor, Andrew T; Lipowska, Malgorzata; Marzilli, Luigi G

2010-03-01

Studies in rats showed that the pharmacokinetics of the tricarbonyl core radiopharmaceutical (99m)Tc(CO)(3)-nitrilotriacetic acid, (99m)Tc(CO)(3)(NTA), were essentially identical to those of (131)I ortho-iodohippuran ((131)I-OIH), the clinical gold standard for the measurement of effective renal plasma flow. Our objective was to compare the pharmacokinetics of these 2 tracers in healthy volunteers. (99m)Tc(CO)(3)(NTA) was prepared with commercially available NTA and a commercially available kit and isolated by reversed-phase high-performance liquid chromatography. Approximately 74 MBq (2 mCi) of (99m)Tc(CO)(3)(NTA) were coinjected with 9.25 MBq (250 microCi) of (131)I-OIH in 9 volunteers, and simultaneous imaging of each tracer was performed for 24 min. Plasma clearances were determined from 8 blood samples obtained 3-90 min after injection using the single-injection, 2-compartment model. Plasma protein binding, red cell uptake, and percentage injected dose in the urine at 30 and 180 min were determined. There was no difference in the plasma clearances of (99m)Tc(CO)(3)(NTA) and (131)I-OIH, 475 +/- 105 mL/min versus 472 +/- 108 mL/min, respectively. The plasma protein binding and red cell uptake of (99m)Tc(CO)(3)(NTA) were 43% +/- 5% and 9% +/- 6%, respectively; both values were significantly lower (P < 0.001) than the plasma protein binding (75% +/- 3%) and red cell uptake (17% +/- 5%) of (131)I-OIH. There was no significant difference in the percentage injected dose recovered in the urine at 30 min and at 3 h; for comparison, the percentage dose in the urine at 3 h was 91% +/- 4% for (99m)Tc(CO)(3)(NTA) and 91% +/- 6% for (131)I-OIH (P = 0.96). Image quality with (99m)Tc(CO)(3)(NTA) was excellent, and the renogram parameters were similar to those of (131)I-OIH. Preliminary results in healthy volunteers suggest that the pharmacokinetic behavior of (99m)Tc(CO)(3)(NTA) is comparable to that of (131)I-OIH.

A novel cell-based assay for inhibitory anti-muscarinic type 3 receptor antibodies in primary Sjögren's syndrome.

PubMed

Bastian, Isabell; Gordon, Tom P; Jackson, Michael W

2015-12-01

Inhibitory autoantibodies acting at the muscarinic acetylcholine receptor type 3 (M3R) are postulated to mediate autonomic dysfunction, including decreased salivary and lacrimal gland output and extra-glandular manifestations, in patients with primary Sjögren's syndrome. However, the contention that anti-M3R antibodies are pathogenic in patients remains untested, due to a lack of assays both sophisticated enough to detect inhibitory anti-M3R antibodies yet suitable for screening large patient cohorts. In the current study, we have established a cell-based bioassay of M3R activity, based on dual transfection of the M3R and a luciferase reporter gene. The bioassay is capable of capturing real-time agonist-mediated signalling of the M3R, which is inhibited specifically by patient IgG that have previously been demonstrated to have anti-M3R activity. The assay can be run in multi-well culture plates, and analysed using simple luminescence readers. As such, the new bioassay incorporating M3R-mediated luciferase transduction is the first assay adaptable to common diagnostic platforms that is capable of determining the presence in patient serum of functionally active anti-M3R autoantibodies. The new bioassay should prove useful for large cohort screening studies aiming to correlate the presence in patients of inhibitory anti-M3R antibodies with symptoms of both glandular and extra-glandular autonomic dysfunction. Copyright © 2015 Elsevier B.V. All rights reserved.

NSUN2-Mediated m5C Methylation and METTL3/METTL14-Mediated m6A Methylation Cooperatively Enhance p21 Translation.

PubMed

Li, Qiu; Li, Xiu; Tang, Hao; Jiang, Bin; Dou, Yali; Gorospe, Myriam; Wang, Wengong

2017-09-01

N6-methyladenosine (m6A) and m5C methylation are two major types of RNA methylation, but the impact of joint modifications on the same mRNA is unknown. Here, we show that in p21 3'UTR, NSUN2 catalyzes m5C modification and METTL3/METTL14 catalyzes m6A modification. Interestingly, methylation at m6A by METTL3/METTL14 facilitates the methylation of m5C by NSUN2, and vice versa. NSUN2-mediated m5C and METTL3/METTL14-mediated m6A methylation synergistically enhance p21 expression at the translational level, leading to elevated expression of p21 in oxidative stress-induced cellular senescence. Our findings on p21 mRNA methylation and expression reveal that joint m6A and m5C modification of the same RNA may influence each other, coordinately affecting protein expression patterns. J. Cell. Biochem. 118: 2587-2598, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Activation of rhenium(I) toward substitution in fac-[Re(N,O'-Bid)(CO)3(HOCH3)] by Schiff-base bidentate ligands (N,O'-Bid).

PubMed

Brink, Alice; Visser, Hendrik G; Roodt, Andreas

2013-08-05

A series of fac-[Re(N,O'-Bid)(CO)3(L)] (N,O'-Bid = monoanionic bidentate Schiff-base ligands with N,O donor atoms; L = neutral monodentate ligand) has been synthesized, and the methanol substitution reactions have been investigated. The complexes were characterized by NMR, IR, and UV-vis spectroscopy. X-ray crystal structures of the compounds fac-[Re(Sal-mTol)(CO)3(HOCH3)], fac-[Re(Sal-pTol)(CO)3(HOCH3)], fac-[Re(Sal-Ph)(CO)3(HOCH3)], and fac-[Re(Sal-Ph)(CO)3(Py)] (Sal-mTol = 2-(m-tolyliminomethyl)phenolato; Sal-pTol = 2-(p-tolyliminomethyl)phenolato; Sal-Ph = 2-(phenyliminomethyl)phenolato; Py = pyridine) are reported. Significant activation for the methanol substitution is induced by the use of the N,O bidentate ligand as manifested by the second order rate constants, with limiting kinetics being observed for the first time. Rate constants (25 °C) (k1 or k3) and activation parameters (ΔHk‡, kJ mol(-1); ΔSk‡, J K(-1) mol(-1)) from Eyring plots for entering nucleophiles as indicated are as follows: fac-[Re(Sal-mTol)(CO)3(HOCH3)] 3-chloropyridine: (k1) 2.33 ± 0.01 M(-1) s(-1); 85.1 ± 0.6, 48 ± 2; fac-[Re(Sal-mTol)(CO)3(HOCH3)] pyridine: (k1) 1.29 ± 0.02 M(-1) s(-1); 92 ± 2, 66 ± 7; fac-[Re(Sal-mTol)(CO)3(HOCH3)] 4-picoline: (k1) 1.27 ± 0.05 M(-1) s(-1); 88 ± 2, 53 ± 6; (k3) 3.9 ± 0.03 s(-1); 78 ± 8, 30 ± 27; (kf) 1.7 ± 0.02 M(-1) s(-1); 86 ± 2, 49 ± 6; fac-[Re(Sal-mTol)(CO)3(HOCH3)] DMAP (k3) 1.15 ± 0.02 s(-1); 88 ± 2, 52 ± 7. An interchange dissociative mechanism is proposed.

Exposure to airborne microorganisms, dust and endotoxin during processing of peppermint and chamomile herbs on farms.

PubMed

Skórska, Czesława; Sitkowska, Jolanta; Krysińska-Traczyk, Ewa; Cholewa, Grazyna; Dutkiewicz, Jacek

2005-01-01

The aim of this study was to determine the levels of microorganisms, dust and endotoxin in the air during processing of peppermint (Mentha piperita) and chamomile (Matricaria recutita) by herb farmers, and to examine the species composition of airborne microflora. Air samples were collected on glass fibre filters by use of personal samplers on 13 farms owned by herb cultivating farmers, located in Lublin province (eastern Poland). The concentrations of total viable microorganisms (bacteria + fungi) in the farm air during processing of peppermint herb were large, within a range from 895.1-6,015.8 x 10(3) cfu/m(3) (median 1,055.3 x 10(3) cfu/m(3)). During processing of chamomile herb they were much lower and varied within a range from 0.88-295.6 x 10(3) cfu/m(3) (median 27.3 x 10(3) cfu/m(3)). Gram-negative bacteria distinctly prevailed during processing of peppermint leaves, forming 46.4-88.5 % of the total airborne microflora. During processing of chamomile herb, Gram-negative bacteria were dominant at 3 out of 6 sampling sites forming 54.7-75.3 % of total microflora, whereas at the remaining 3 sites the most common were fungi forming 46.2-99.9 % of the total count. The species Pantoea agglomerans (synonyms: Erwinia herbicola, Enterobacter agglomerans ), having strong allergenic and endotoxic properties, distinctly prevailed among Gram-negative isolates. Among fungi, the most common species was Alternaria alternata. The concentrations of airborne dust and endotoxin determined on the examined herb farms were large. The concentrations of airborne dust during peppermint and chamomile processing ranged from 86.7-958.9 mg/m(3), and from 1.1-499.2 mg/m(3), respectively (medians 552.3 mg/m(3) and 12.3 mg/m(3)). The concentrations of airborne endotoxin determined during peppermint and chamomile processing were within a wide range 1.53-208.33 microg/m(3) and 0.005-2604.19 microg/m(3) respectively (medians 57.3 microg/m(3) and 0.96 microg/m(3)). In conclusion, farmers cultivating peppermint are exposed during processing of this herb to large concentrations of airborne microorganisms, dust and endotoxin posing a risk of work-related respiratory disease. The exposure to bioaerosols during processing of chamomile is lower; nevertheless, peak values create a respiratory risk for exposed farmers.

Improving brightness and photostability of green and red fluorescent proteins for live cell imaging and FRET reporting

PubMed Central

Bajar, Bryce T.; Wang, Emily S.; Lam, Amy J.; Kim, Bongjae B.; Jacobs, Conor L.; Howe, Elizabeth S.; Davidson, Michael W.; Lin, Michael Z.; Chu, Jun

2016-01-01

Many genetically encoded biosensors use Förster resonance energy transfer (FRET) to dynamically report biomolecular activities. While pairs of cyan and yellow fluorescent proteins (FPs) are most commonly used as FRET partner fluorophores, respectively, green and red FPs offer distinct advantages for FRET, such as greater spectral separation, less phototoxicity, and lower autofluorescence. We previously developed the green-red FRET pair Clover and mRuby2, which improves responsiveness in intramolecular FRET reporters with different designs. Here we report the engineering of brighter and more photostable variants, mClover3 and mRuby3. mClover3 improves photostability by 60% and mRuby3 by 200% over the previous generation of fluorophores. Notably, mRuby3 is also 35% brighter than mRuby2, making it both the brightest and most photostable monomeric red FP yet characterized. Furthermore, we developed a standardized methodology for assessing FP performance in mammalian cells as stand-alone markers and as FRET partners. We found that mClover3 or mRuby3 expression in mammalian cells provides the highest fluorescence signals of all jellyfish GFP or coral RFP derivatives, respectively. Finally, using mClover3 and mRuby3, we engineered an improved version of the CaMKIIα reporter Camuiα with a larger response amplitude. PMID:26879144

3.0-3.7μm infrared sensor system for cell analysis

NASA Astrophysics Data System (ADS)

van den Driesche, Sander; Witarski, Wojciech; Vellekoop, Michael J.

2009-05-01

In this contribution we present a novel LED-photodiode based infrared absorbance sensor in the wavelength range of 3.0 - 3.7 μm for cell analysis. Instead of using time consuming and expensive labelling and staining techniques to distinguish healthy from malignant cell types, this IR sensor system can perform faster, cheaper and without the need of additional chemicals. Depending on the used narrow bandpass filters, absorbance due to specific molecular vibration can be measured, such as the functional absorbance peaks at 3.38 μm (CH3-antisymmetric stretch), 3.42 μm (CH2- antisymmetric stretch), 3.48 μm (CH3-symmetric stretch) and 3.51 μm (CH2-symmetric stretch). For normalization and baseline correction the absorbance at wavelengths 3.33 and 3.57 μm are used. By recording the IR absorbance spectra of healthy and malignant epithelial kidney cell lines with an IR spectroscope, we found significant differences in the absorbance ratio 3.51 μm / 3.42 μm (CH2-symmetric/antisymmetric stretch). This result has led us to a sensor concept where only four wavelengths are being measured. In the 3.0 - 3.7 μm wavelength region a low cost LED-photodiode system can be used instead of a spectroscope. Yeast cells, which also contain the CH2 symmetric and antisymmetric stretch bands, are used to validate this sensor system and to make a first comparison of the system to spectroscopic recordings. Sensor experiments on dried spots of baker's yeast on calcium-fluoride slides yielded a comparable CH2 stretch ratio with the IR spectroscope measurement. This confirms the usability of the sensor to measure the CH2 stretch ratio and its potential for fast, label-free and low cost screening of cell samples.

Tri-Ponderal Mass Index vs. Fat Mass/Height3 as a Screening Tool for Metabolic Syndrome Prediction in Colombian Children and Young People

PubMed Central

Correa-Bautista, Jorge Enrique; Carrillo, Hugo Alejandro; Schmidt-RioValle, Jacqueline; González-Ruíz, Katherine

2018-01-01

Tri-ponderal mass index (TMI) and fat mass index (FMI) have been proposed as alternative approaches for assessing body fat since BMI does not ensure an accurate screening for obesity and overweight status in children and adolescents. This study proposes thresholds of the TMI and FMI for the prediction of metabolic syndrome (MetS) in children and young people. For this purpose, a cross-sectional study was conducted on 4673 participants (57.1% females), who were 9–25 years of age. As part of the study, measurements of the subjects’ weight, waist circumference, serum lipid indices, blood pressure and fasting plasma glucose were taken. Body composition was measured by bioelectrical impedance analysis (BIA). The TMI and FMI were calculated as weight (kg)/height (m3) and fat mass (kg)/height (m3), respectively. Following the International Diabetes Federation (IDF) definition, MetS is defined as including three or more metabolic abnormalities. Cohort-specific thresholds were established to identify Colombian children and young people at high risk of MetS. The thresholds were applied to the following groups: (i) a cohort of children where the girls’ TMI ≥ 12.13 kg/m3 and the boys’ TMI ≥ 12.10 kg/m3; (ii) a cohort of adolescents where the girls’ TMI ≥ 12.48 kg/m3 and the boys’ TMI ≥ 11.19 kg/m3; (iii) a cohort of young adults where the women’s TMI ≥ 13.21 kg/m3 and the men’s TMI ≥ 12.19 kg/m3. The FMI reference cut-off values used for the different groups were as follows: (i) a cohort of children where the girls’ FMI ≥ 2.59 fat mass/m3 and the boys’ FMI ≥ 1.98 fat mass/m3; (ii) a cohort of adolescents where the girls’ FMI ≥ 3.12 fat mass/m3 and the boys’ FMI ≥ 1.46 fat mass/m3; (iii) a cohort of adults where the women’s FMI ≥ 3.27 kg/m3 and the men’s FMI ≥ 1.65 kg/m3. Our results showed that the FMI and TMI had a moderate discriminatory power to detect MetS in Colombian children, adolescents, and young adults. PMID:29584641

Alkali metal and ammonium fluoro(trifluoroacetato)metallates M'[ M''3(μ3-F)(CF3COO)6(CF3COOH)3], where M' = Li, Na, K, NH4, Rb, or Cs and M'' = Ni or Co. Synthesis and crystal structures

NASA Astrophysics Data System (ADS)

Tereshchenko, D. S.; Morozov, I. V.; Boltalin, A. I.; Karpova, E. V.; Glazunova, T. Yu.; Troyanov, S. I.

2013-01-01

A series of fluoro(trifluoroacetato)metallates were synthesized by crystallization from solutions in trifluoroacetic acid containing nickel(II) or cobalt(II) nitrate hydrates and alkali metal or ammonium fluorides: Li[Ni3(μ3-F)(CF3COO)6(CF3COOH)3](CF3COOH)3 ( I), M'[Ni3(μ3-F)(CF3COO)6(CF3COOH)3] ( M' = Na ( II), NH4 ( IV), Rb ( V), and Cs ( VI)), NH4[Co3(μ3-F) (CF3COO)6(CF3COOH)3] ( III), and Cs[Ni3(μ3-F)(CF3COO)6(CF3COOH)3](CF3COOH)0.5 ( VII). The crystal structures of these compounds were determined by single-crystal X-ray diffraction. All structures contain triangular trinuclear complex anions [ M 3″(μ3-F)(CF3COO)6(CF3COOH)3]- ( M″ = Ni, Co) structurally similar to trinuclear 3d metal oxo carboxylate complexes. The three-coordinated F atom is located at the center of the triangle formed by Ni(II) or Co(II) atoms. The metal atoms are linked in pairs by six bridging trifluoroacetate groups located above and below the plane of the [ M″3 F] triangle. The oxygen atoms of the axial CF3COOH molecules complete the coordination environment of M″ atoms to an octahedron.

Preparation and Characterization of the Binary Group 13 Azides M(N3)3 and M(N3)3’CH3CN (M = Ga, In, TI), [Ga(N3)5](2-), and [M(N3)6](3-) (M = In, TI) (Preprint)

DTIC Science & Technology

2011-05-24

semiconductor and optoelectronic applications. Although most of these efforts were devoted to gallium azides, aluminium and indium azides were also...their usefulness for semiconductor and optoelectronic applications. Although most of these efforts were devoted to gallium azides,[20,21] aluminium and...57(1) N(7) -152(5) 6417(2) 7317(2) 54(1) N(8) 20(5) 6903(2) 7687(2) 48(1) N(9) 148(4) 7388(3) 8011 (3) 80(2) P(1) 4132(1) 6289(1) 9090(1) 30(1

The Moon mineralogy mapper (M3) on Chandrayaan-1

USGS Publications Warehouse

Pieters, C.M.; Boardman, J.; Buratti, B.; Chatterjee, A.; Clark, R.; Glavich, T.; Green, R.; Head, J.; Isaacson, P.; Malaret, E.; McCord, T.; Mustard, J.; Petro, N.; Runyon, C.; Staid, M.; Sunshine, J.; Taylor, L.; Tompkins, S.; Varanasi, P.; White, M.

2009-01-01

The Moon Mineralogy Mapper (M3) is a NASA-supported guest instrument on ISRO's remote sensing mission to Moon, Chandrayaan-1. The M3 is an imaging spectrometer that operates from the visible into the near-infrared (0.42-3.0 ??m) where highly diagnostic mineral absorption bands occur. Over the course of the mission M3 will provide low resolution spectroscopic data for the entire lunar surface at 140 m/pixel (86 spectral channels) to be used as a base-map and high spectral resolution science data (80 m/pixel; 260 spectral channels) for 25-50% of the surface. The detailed mineral assessment of different lunar terrains provided by M3 is principal information needed for understanding the geologic evolution of the lunar crust and lays the foundation for focused future in-depth exploration of the Moon.

Muscarinic binding sites in cultured bovine pulmonary arterial endothelial cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aronstam, R.S.; Catravas, J.D.; Ryan, U.S.

The authors have previously reported a) the presence of muscarinic binding sites on cultured bovine pulmonary arterial endothelial cells (BPAE; 2,000 sites/cell) and b) that acetylcholine inhibits the release of thromboxane B/sub 2/ fro BPAE. Since the authors findings could reflect muscarinic receptors (mAChR) on BPAE, they have further investigated the nature of BPAE muscarinic binding sites and contrast them to those of known functional mAChR. Muscarinic binding sites on BPAE resembled mAChR in that a) the binding of 3 nM /sup 3/H QNB was inhibited by muscarinic agonists and antagonists; b) /sup 3/H QNB binding was 30 times moremore » sensitive to R(-)- than to S(+)-QNB; c) carbamylcholine binding was resolved into high and low affinity components (IC50's = 0.04 and 2 ..mu..M; d) 5'-guanylylimidodiphosphate (100 ..mu..M) shifted agonist binding curves to the right by a factor of 3; 4) the atropine-sensitive binding of /sup 3/H oxotremorine-M (/sup 3/H-OXO-M) was depressed by the guanine nucleotide (IC50 + 60 ..mu..M). However, although gallamine allosterically regulates mAChR binding in other tissues, it did not affect the rates of dissociation of /sup 3/H QNB, /sup 3/H methylscopolamine or /sup 3/H OXO-M from BPAE binding sites. Thus, BPAE muscarinic binding sites posses many but not all of the properties associated with functional mAChR.« less

Synthesis of Tc-99m labeled 1,2,3-triazole-4-yl c-met binding peptide as a potential c-met receptor kinase positive tumor imaging agent.

PubMed

Kim, Eun-Mi; Joung, Min-Hee; Lee, Chang-Moon; Jeong, Hwan-Jeong; Lim, Seok Tae; Sohn, Myung-Hee; Kim, Dong Wook

2010-07-15

The mesenchymal-epithelial transition factor (c-Met), which is related to tumor cell growth, angiogenesis and metastases, is known to be overexpressed in several tumor types. In this study, we synthesized technetium-99m labeled 1,2,3-triazole-4-yl c-Met binding peptide (cMBP) derivatives, prepared by solid phase peptide synthesis and the 'click-to-chelate' protocol for the introduction of tricarbonyl technetium-99m, as a potential c-Met receptor kinase positive tumor imaging agent, and evaluated their in vitro c-Met binding affinity, cellular uptake, and stability. The (99m)Tc labeled cMBP derivatives ([(99m)Tc(CO)(3)]12, [(99m)Tc(CO)(3)]13, and [(99m)Tc(CO)(3)]14) were prepared in 85-90% radiochemical yields. The cold surrogate cMBP derivatives, [Re(CO)(3)]12, [Re(CO)(3)]13, and [Re(CO)(3)]14, were shown to have high binding affinities (0.13 microM, 0.06 microM, and 0.16 microM, respectively) to a purified cMet/Fc chimeric recombinant protein. In addition, the in vitro cellular uptake and inhibition studies demonstrated the high specific binding of these (99m)Tc labeled cMBP derivatives ([(99m)Tc(CO)(3)]12-14) to c-Met receptor positive U87MG cells. 2010 Elsevier Ltd. All rights reserved.

Millimeter Wave Filter Design with Suspended Stripline

DTIC Science & Technology

1989-09-01

VARIATIONAL CALCULATION METHOD.....................44 B. ALTERNATE ASSUMPTION FOR CHARGE DISTRIBUTION....... 47 APPE’NDIX B. FORTRAN PROGRAM...negative) of K. Instead of equation (99) the K was chosen such as to maximize the line capacitance C (in this case K = 3). B. ALTERNATE ASSUMPTION FOR...REAL Gl,G2,G3,HH1,T,KQ,56,C1M,C2M,C3M,C4M,NCAPM, CAPM REAL ClEC2E,C3E,C4E,NCAPE,CAPE,CO INTEGER IMAX,MMAXNMAX,JMAX, I,J,Nl,N2,M2,M,N,I2,J2,I3,J3,L

Orthodontic extrusion of the lower third molar with an orthodontic mini implant.

PubMed

Park, Wonse; Park, Joon-Soo; Kim, Yun-Mi; Yu, Hyung-Seog; Kim, Kee-Deog

2010-10-01

Neurologic changes owing to damage to the inferior alveolar nerve (IAN) are the most serious complication of lower third molar (M3) extraction because of their close spatial relationship. We adopted the concept of regional orthodontic treatment and extrusion, using skeletal anchorage with an orthodontic mini implant. Two malformed M3s that were closely apposed to the IAN were extruded with the aid of 3 or 4 orthodontic brackets and a mini implant. Both of the M3s were extruded successfully. The patients experienced little discomfort with the orthodontic appliances and there was neither permanent neurologic damage nor fracture of the root fragments following subsequent M3 extraction. Orthodontic treatment using a miniscrew to separate the IAN and M3, or luxation of the M3 may be a good alternative treatment option for extrusion of a vertically impacted lower M3 with fragile roots. Copyright © 2010 Mosby, Inc. All rights reserved.

Analysis of thyroid hormone receptor {beta}A mRNA expression in Xenopus laevis tadpoles as a means to detect agonism and antagonism of thyroid hormone action

DOE Office of Scientific and Technical Information (OSTI.GOV)

Opitz, Robert; Lutz, Ilka; Nguyen, Ngoc-Ha

2006-04-01

Amphibian metamorphosis represents a unique biological model to study thyroid hormone (TH) action in vivo. In this study, we examined the utility of thyroid hormone receptors {alpha} (TR{alpha}) and {beta}A (TR{beta}A) mRNA expression patterns in Xenopus laevis tadpoles as molecular markers indicating modulation of TH action. During spontaneous metamorphosis, only moderate changes were evident for TR{alpha} gene expression whereas a marked up-regulation of TR{beta}A mRNA occurred in hind limbs (prometamorphosis), head (late prometamorphosis), and tail tissue (metamorphic climax). Treatment of premetamorphic tadpoles with 1 nM 3,5,3'-triiodothyronine (T3) caused a rapid induction of TR{beta}A mRNA in head and tail tissue withinmore » 6 to 12 h which was maintained for at least 72 h after initiation of T3 treatment. Developmental stage had a strong influence on the responsiveness of tadpole tissues to induce TR{beta}A mRNA during 24 h treatment with thyroxine (0, 1, 5, 10 nM T4) or T3 (0, 1, 5, 10 nM). Premetamorphic tadpoles were highly sensitive in their response to T4 and T3 treatments, whereas sensitivity to TH was decreased in early prometamorphic tadpoles and strongly diminished in late prometamorphic tadpoles. To examine the utility of TR{beta}A gene expression analysis for detection of agonistic and antagonistic effects on T3 action, mRNA expression was assessed in premetamorphic tadpoles after 48 h of treatment with the synthetic agonist GC-1 (0, 10, 50, 250 nM), the synthetic antagonist NH-3 (0, 40, 200, 1000 nM), and binary combinations of NH-3 (0, 40, 200, 1000 nM) and T3 (1 nM). All tested concentrations of GC-1 as well as the highest concentration of NH-3 caused an up-regulation of TR{beta}A expression. Co-treatment with NH-3 and T3 revealed strong antagonistic effects by NH-3 on T3-induced TR{beta}A mRNA up-regulation. Results of this study suggest that TR{beta}A mRNA expression analysis could serve as a sensitive molecular testing approach to study effects of environmental compounds on the thyroid system in X. laevis tadpoles.« less

Five-year trends of second-hand smoke exposure in Greece: a comparison between complete, partial, and prelegislation levels.

PubMed

Vardavas, Constantine I; Anagnostopoulos, Nektarios; Patelarou, Evridiki; Minas, Markos; Nakou, Chrysanthi; Dramba, Vassiliki; Giourgouli, Gianna; Bagkeris, Emmanouil; Gourgoulianis, Konstantinos; Pattaka, Paraskevi; Antoniadis, Antonis; Lionis, Christos; Bertic, Monique; Dockery, Douglas; Connolly, Gregory N; Behrakis, Panagiotis K

2012-12-01

Our aim was to assess second-hand smoke (SHS) exposure in hospitality venues after the smoke-free legislation implemented in September 2010 in Greece and to compare with when a partial ban was in place and in 2006 when no ban was in place. Hospitality venues were prospectively assessed for their indoor concentrations of particulate matter (PM(2.5)) during the partial ban phase (n=149) and the complete ban phase (n=120, 80% followed up), while overall and matched by venue comparisons were also performed (no ban vs. partial ban vs. complete ban). Comparisons with previously collected data in 2006 when no ban was in place also was performed. Indoor air levels of PM(2.5) attributable to SHS dropped following the transition from a partial to a complete ban by 34% (137 μg/m(3) vs. 90 μg/m(3), p=0.003). This drop was larger in bars (from 195 μg/m(3) to 121 μg/m(3)), than in cafes (124 μg/m(3) vs. 87 μg/m(3)) or restaurants (42 μg/m(3) vs. 39 μg/m(3)). PM(2.5) concentrations between 2006 (no ban) and the partial ban of 2010 were also found to decrease by 94 μg/m(3); however, among matched venues, the levels of indoor air pollution were not found to change significantly (218 μg/m(3) vs. 178 μg/m(3), p=0.58). Comparing the 2010 complete ban results (n=120) with previously collected data from 2006 when no ban was in place (n=43), overall PM(2.5) concentrations were found to fall from 268 μg/m(3) to 89 μg/m(3), while a matched analysis found a significant reduction in PM(2.5) concentrations (249 μg/m(3) vs. 46 μg/m(3), p=0.011). The complete ban of smoking in hospitality venues in Greece led to a reduction in SHS exposure, in comparison to when the partial ban or no ban was in place; however, exposure to SHS was not eliminated indicating the need for stronger enforcement.

The NO donor DETA-NONOate reversibly activates an inward current in neurones and is not mediated by the released nitric oxide

PubMed Central

Thompson, AJ; Mander, PK; Brown, GC

2009-01-01

Background and purpose: It has been previously shown that high levels of nitric oxide (NO), from NO donors, kill neurones, but the mechanisms are unclear. Experimental approach: The effects of NO donors on the electrical properties of rat cultured cerebellar granule cells (CGC neurones) were investigated using the whole-cell patch-clamp technique. Key results: The NO donor (Z)-1-[2-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate (DETA-NONOate or NOC-18) caused a rapid, persistent, but fully reversible inward current that was associated with an increase in baseline noise and was concentration dependent (100 µM–10 mM). The response to 3 mM DETA-NONOate was completely inhibited by 1 mM gadolinium, but not by NO scavengers (1 mM haemoglobin or 1 mM PTIO) or glutamate receptor antagonists (10 µM MK-801 or 60 µM CNQX). Application of decomposed 3 mM DETA-NONOate or 3 mM nitrite had no effect. In contrast, the NO donor S-nitrosoglutathione (GSNO) caused a rapid, persistent, but fully reversible outward current that was also concentration dependent (1–10 mM). The 3 mM GSNO response was unaltered by NO scavengers, glutamate antagonists or gadolinium, but was mimicked by decomposed 3 mM GSNO and 3 mM oxidized glutathione. Conclusions and implications: These results suggest that DETA-NONOate directly activates cation-selective channels, causing an inward current in CGCs. In contrast, GSNO causes an outward current in these cells. Some of the effects of these NO donors are independent of NO, and thus caution is required in interpreting results when using high concentrations of these compounds. PMID:19785659

Study on the traffic air pollution inside and outside a road tunnel in Shanghai, China.

PubMed

Zhou, Rui; Wang, Shanshan; Shi, Chanzhen; Wang, Wenxin; Zhao, Heng; Liu, Rui; Chen, Limin; Zhou, Bin

2014-01-01

To investigate the vehicle induced air pollution situations both inside and outside the tunnel, the field measurement of the pollutants concentrations and its diurnal variations was performed inside and outside the Xiangyin tunnel in Shanghai from 13:00 on April 24th to 13:00 on April 25th, 2013. The highest hourly average concentrations of pollutants were quantified that CO, NO, NO2 and NOX inside the tunnel were 13.223 mg/m3, 1.829 mg/m3, 0.291 mg/m3 and 3.029 mg/m3, respectively, while the lowest ones were 3.086 mg/m3, 0.344 mg/m3, 0.080 mg/m3 and 0.619 mg/m3. Moreover, the concentrations of pollutants were higher during the daytime, and lower at night, which is relevant to the traffic conditions inside the tunnel. Pollutants concentrations inside the tunnel were much higher than those outside the tunnel. Then in a case of slow wind, the effect of wind is much smaller than the impact of pollution sources. Additionally, the PM2.5 concentrations climbed to the peak sharply (468.45 µg/m3) during the morning rush hours. The concentrations of organic carbon (OC) and elemental carbon (EC) in PM2.5 inside the tunnel were 37.09-99.06 µg/m3 and 22.69-137.99 µg/m3, respectively. Besides, the OC/EC ratio ranged from 0.72 to 2.19 with an average value of 1.34. Compared with the results of other tunnel experiments in Guangzhou and Shenzhen, China, it could be inferred that the proportion of HDVs through the Xiangyin tunnel is relatively lower.

/sup 3/H-PAF-acether displacement and inhibition of binding in intact human platelets by BN 52021

DOE Office of Scientific and Technical Information (OSTI.GOV)

Korth, R.; Le Couedic, J.P.; Benveniste, J.

1986-03-05

Intact washed human platelets incubated at 20/sup 0/C in Tyrode's buffer containing 0.25% (w/v) bovine serum albumin bound /sup 3/H paf-acether in a concentration (0-6.5 nM) and time (0-60 min) dependent manner (n=3). BN 52021 (60 ..mu..M) a chemically defined extract from Ginkgo biloba inhibited the binding of increasing concentrations of /sup 3/H paf-acether. Calculated differences between /sup 3/H paf-acether binding in the presence or absence of BN 52021 (60 ..mu..M) reached nearly a plateau in concentrations higher than 0.65 nM /sup 3/H paf-acether. Increasing concentrations of BN 52021 (0-60 ..mu..M) as well as of unlabelled paf-acether (0-50 nM) preventedmore » within 15 min /sup 3/H paf-acether binding (0.65 nM) to platelets in a concentration-dependent way. Increasing BN 52021 concentrations (0-60 ..mu..M) also displaced platelet-bound /sup 3/H paf-acether (0.65 nM) in a concentration-dependent way. Displacement increased with the time length of platelet incubation with BN 52021 and reached a plateau at 15 min. Platelet-bound /sup 3/H paf-acether displacement of 28.3 +/- 6.3%, 31.1 +/- 4.0% and 26.7 +/- 5.6% was observed using 50 nM unlabelled paf-acether, 60 ..mu..M BN 52021 or both substances together (vs 4.3 +/- 7.2% for vehicle alone). No degradation of /sup 3/H paf-acether occurred as assessed by high pressure liquid chromatography. These results demonstrate that BN 52021 competes directly with paf-acether binding sites on human platelets.« less

Study on the Traffic Air Pollution inside and outside a Road Tunnel in Shanghai, China

PubMed Central

Zhou, Rui; Wang, Shanshan; Shi, Chanzhen; Wang, Wenxin; Zhao, Heng; Liu, Rui; Chen, Limin; Zhou, Bin

2014-01-01

To investigate the vehicle induced air pollution situations both inside and outside the tunnel, the field measurement of the pollutants concentrations and its diurnal variations was performed inside and outside the Xiangyin tunnel in Shanghai from 13:00 on April 24th to 13:00 on April 25th, 2013. The highest hourly average concentrations of pollutants were quantified that CO, NO, NO2 and NOX inside the tunnel were 13.223 mg/m3, 1.829 mg/m3, 0.291 mg/m3 and 3.029 mg/m3, respectively, while the lowest ones were 3.086 mg/m3, 0.344 mg/m3, 0.080 mg/m3 and 0.619 mg/m3. Moreover, the concentrations of pollutants were higher during the daytime, and lower at night, which is relevant to the traffic conditions inside the tunnel. Pollutants concentrations inside the tunnel were much higher than those outside the tunnel. Then in a case of slow wind, the effect of wind is much smaller than the impact of pollution sources. Additionally, the PM2.5 concentrations climbed to the peak sharply (468.45 µg/m3) during the morning rush hours. The concentrations of organic carbon (OC) and elemental carbon (EC) in PM2.5 inside the tunnel were 37.09–99.06 µg/m3 and 22.69–137.99 µg/m3, respectively. Besides, the OC/EC ratio ranged from 0.72 to 2.19 with an average value of 1.34. Compared with the results of other tunnel experiments in Guangzhou and Shenzhen, China, it could be inferred that the proportion of HDVs through the Xiangyin tunnel is relatively lower. PMID:25386920

Customer exposure to MTBE, TAME, C6 alkyl methyl ethers, and benzene during gasoline refueling.

PubMed

Vainiotalo, S; Peltonen, Y; Ruonakangas, A; Pfäffli, P

1999-02-01

We studied customer exposure during refueling by collecting air samples from customers' breathing zone. The measurements were carried out during 4 days in summer 1996 at two Finnish self-service gasoline stations with "stage I" vapor recovery systems. The 95-RON (research octane number) gasoline contained approximately 2.7% methyl tert-butyl ether (MTBE), approximately 8.5% tert-amyl methyl ether (TAME), approximately 3.2% C6 alkyl methyl ethers (C6 AMEs), and 0.75% benzene. The individual exposure concentrations showed a wide log-normal distribution, with low exposures being the most frequent. In over 90% of the samples, the concentration of MTBE was higher (range <0.02-51 mg/m3) than that of TAME. The MTBE values were well below the short-term (15 min) threshold limits set for occupational exposure (250-360 mg/m3). At station A, the geometric mean concentrations in individual samples were 3.9 mg/m3 MTBE and 2. 2 mg/m3 TAME. The corresponding values at station B were 2.4 and 1.7 mg/m3, respectively. The average refueling (sampling) time was 63 sec at station A and 74 sec at station B. No statistically significant difference was observed in customer exposures between the two service stations. The overall geometric means (n = 167) for an adjusted 1-min refueling time were 3.3 mg/m3 MTBE and 1.9 mg/m3 TAME. Each day an integrated breathing zone sample was also collected, corresponding to an arithmetic mean of 20-21 refuelings. The overall arithmetic mean concentrations in the integrated samples (n = 8) were 0.90 mg/m3 for benzene and 0.56 mg/m3 for C6 AMEs calculated as a group. Mean MTBE concentrations in ambient air (a stationary point in the middle of the pump island) were 0.16 mg/m3 for station A and 0.07 mg/m3 for station B. The mean ambient concentrations of TAME, C6 AMEs, and benzene were 0.031 mg/m3, approximately 0.005 mg/m3, and approximately 0.01 mg/m3, respectively, at both stations. The mean wind speed was 1.4 m/sec and mean air temperature was 21 degreesC. Of the gasoline refueled during the study, 75% was 95 grade and 25% was 98/99 grade, with an oxygenate (MTBE) content of 12.2%.

Comparative Studies of the Thick-Toed Geckos after the 16 and 12 Days Spaceflight in <> Experiments

NASA Astrophysics Data System (ADS)

Nikitin, V. B.; Proshchina, A. E.; Kharlamova, A. S.; Barabanov, V. M.; Krivova, J. S.; Godovalova, O. S.; Savelieva, E. S.; Makarov, A. N.; Gulimova, V. I.; Okshtein, I. L.; Naidenko, S. V.; Souza, K. A.; Almeida, E. A. C.; Ilyin, E. A.; Saveliev, S. V.

2008-06-01

In our study we compare the data from analysis of thick-toed geckoes Pachydactylus turneri from 16 and 12 days spaceflights onboard «Foton-M2» (M2) and «Foton-M3» (M3) satellites respectively. These studies were realized in the frames of Russian-American joint experiments. In M2 they were performed on 4 females and 1 male in each of the following groups: flight (F), basal (BC) and delayed synchronous (SC) controls. In M3 there were 5 females in each group. The animals were euthanized and examined using traditional histology, immunohistochemistry and X-ray microtomography. Mallory, Nissl and hematoxylin-eosin staining were used to compare the condition of brain, heart, liver, pancreas, spleen and small intestine. Brain and pancreas were also studied immunohistochemically. Behavior was registered by video camera in F and SC (M3). Thus we confirm the previous assumption that geckoes can preserve in weightlessness their ability to fi x themselves to the surfaces by their toe pads. We did not reveal in liver, pancreas, spleen and small intestine of F-M3 geckoes such evident changes like in F-M2 group. Glial destruction was detected immunohistochemically in the brains of F-M3 geckoes, especially in the cortical structures and epithalamus. Gluckocorticoids level for geckoes' feces in F-M2 was 4 times higher than in SC-M2 whereas the results for M3 were almost the same. Microtomografi c analysis of the femur bones showed some redistribution of the trabeculae in F-M3 group which occured in the direction from the outer compact bone to the bone center. Thus we conclude that in most structures of F-M3 animals the changes were less then in F-M2 ones. It can be explaned by shorter duration of M3 flight, higer temperature and the presence of water source. More prolonged experiments with larger groups of geckoes are necessary to verify the obtained data. Probably geckoes are well preadapted to conditions of spaceflight due to their specific biology.

Randomised clinical trial: a 'nudge' strategy to modify endoscopic sedation practice.

PubMed

Harewood, G C; Clancy, K; Engela, J; Abdulrahim, M; Lohan, K; O'Reilly, C

2011-07-01

In behavioural economics, a 'nudge' describes configuration of a choice to encourage a certain action without taking away freedom of choice. To determine the impact of a 'nudge' strategy - prefilling either 3mL or 5mL syringes with midazolam - on endoscopic sedation practice. Consecutive patients undergoing sedation for EGD or colonoscopy were enrolled. On alternate weeks, midazolam was prefilled in either 3mL or 5mL syringes. Preprocedure sedation was administered by the endoscopist to achieve moderate conscious sedation; dosages were at the discretion of the endoscopist. Meperidine was not prefilled. Overall, 120 patients received sedation for EGD [59 (5mL), 61 (3mL)] and 86 patients were sedated for colonoscopy [38 (5mL), 48 (3mL)]. For EGDs, average midazolam dose was significantly higher in the 5-mL group (5.2mg) vs. 3-mL group (3.3mg), (P<0.0001); for colonoscopies, average midazolam dose was also significantly higher in the 5-mL group (5.1mg) vs. 3-mL group (3.3mg), (P<0.0001). There was no significant difference in mean meperidine dose (42.1mg vs. 42.8mg, P=0.9) administered to both colonoscopy groups. No adverse sedation-related events occurred; no patient required reversal of sedation. These findings demonstrate that 'nudge' strategies may hold promise in modifying endoscopic sedation practice. Further research is required to explore the utility of 'nudges' in impacting other aspects of endoscopic practice. © 2011 Blackwell Publishing Ltd.

Opposing functions of spinal M2, M3, and M4 receptor subtypes in regulation of GABAergic inputs to dorsal horn neurons revealed by muscarinic receptor knockout mice.

PubMed

Zhang, Hong-Mei; Chen, Shao-Rui; Matsui, Minoru; Gautam, Dinesh; Wess, Jürgen; Pan, Hui-Lin

2006-03-01

Spinal muscarinic acetylcholine receptors (mAChRs) play an important role in the regulation of nociception. To determine the role of individual mAChR subtypes in control of synaptic GABA release, spontaneous inhibitory postsynaptic currents (sIPSCs) and miniature IPSCs (mIPSCs) were recorded in lamina II neurons using whole-cell recordings in spinal cord slices of wild-type and mAChR subtype knockout (KO) mice. The mAChR agonist oxotremorine-M (3-10 microM) dose-dependently decreased the frequency of GABAergic sIPSCs and mIPSCs in wild-type mice. However, in the presence of the M2 and M4 subtype-preferring antagonist himbacine, oxotremorine-M caused a large increase in the sIPSC frequency. In M3 KO and M1/M3 double-KO mice, oxotremorine-M produced a consistent decrease in the frequency of sIPSCs, and this effect was abolished by himbacine. We were surprised to find that in M2/M4 double-KO mice, oxotremorine-M consistently increased the frequency of sIPSCs and mIPSCs in all neurons tested, and this effect was completely abolished by 4-diphenylacetoxy-N-methylpiperidine methiodide, an M3 subtype-preferring antagonist. In M2 or M4 single-KO mice, oxotremorine-M produced a variable effect on sIPSCs; it increased the frequency of sIPSCs in some cells but decreased the sIPSC frequency in other neurons. Taken together, these data strongly suggest that activation of the M3 subtype increases synaptic GABA release in the spinal dorsal horn of mice. In contrast, stimulation of presynaptic M2 and M4 subtypes predominantly attenuates GABAergic inputs to dorsal horn neurons in mice, an action that is opposite to the role of M2 and M4 subtypes in the spinal cord of rats.

Reaction of singlet-excited 2,3-diazabicyclo[2.2.2]oct-2-ene and tert-butoxyl radicals with aryl-substituted benzofuranones.

PubMed

Lundgren, Cecilia Vannesjö; Koner, Apurba L; Tinkl, Michael; Pischel, Uwe; Nau, Werner M

2006-03-03

5,7-Di-tert-butyl-3-aryl-3H-benzofuran-2-ones are lactones with potential antioxidant activity, owing to their abstractable benzylic C-H hydrogens. The fluorescence quenching of the azoalkane 2,3-diazabicyclo[2.2.2]oct-2-ene (DBO), an established probe for the hydrogen-donor propensity of chain-breaking antioxidants, was investigated for 16 aryl-substituted benzofuranone derivatives [m,m-(CF3)2, p-CN, m-CN, p-CF3, p-COOCH3, m-CF3, p-Cl, p-F, H, m-CH3, p-CH3, m,p-(CH3)2, p-OCH3, o-CH3, o-CF3, o,m-(CH3)2]. Analysis of the rate data in terms of a linear free energy relationship yielded a reaction constant of rho = +0.35. This implies that n,pi*-excited DBO acts as nucleophilic species. In contrast, hydrogen abstraction of tert-butoxyl radicals from the benzofuranones was accelerated by electron-donating substituents (rho = -0.23), in conformity with the electrophilic character of oxygen-centered alkoxyl radicals. Possible implications for the optimization of the hydrogen-donor propensity of antioxidants through structural variation are discussed.

Unique Footprint in the scl1.3 Locus Affects Adhesion and Biofilm Formation of the Invasive M3-Type Group A Streptococcus.

PubMed

Bachert, Beth A; Choi, Soo J; LaSala, Paul R; Harper, Tiffany I; McNitt, Dudley H; Boehm, Dylan T; Caswell, Clayton C; Ciborowski, Pawel; Keene, Douglas R; Flores, Anthony R; Musser, James M; Squeglia, Flavia; Marasco, Daniela; Berisio, Rita; Lukomski, Slawomir

2016-01-01

The streptococcal collagen-like proteins 1 and 2 (Scl1 and Scl2) are major surface adhesins that are ubiquitous among group A Streptococcus (GAS). Invasive M3-type strains, however, have evolved two unique conserved features in the scl1 locus: (i) an IS1548 element insertion in the scl1 promoter region and (ii) a nonsense mutation within the scl1 coding sequence. The scl1 transcript is drastically reduced in M3-type GAS, contrasting with a high transcription level of scl1 allele in invasive M1-type GAS. This leads to a lack of Scl1 expression in M3 strains. In contrast, while scl2 transcription and Scl2 production are elevated in M3 strains, M1 GAS lack Scl2 surface expression. M3-type strains were shown to have reduced biofilm formation on inanimate surfaces coated with cellular fibronectin and laminin, and in human skin equivalents. Repair of the nonsense mutation and restoration of Scl1 expression on M3-GAS cells, restores biofilm formation on cellular fibronectin and laminin coatings. Inactivation of scl1 in biofilm-capable M28 and M41 strains results in larger skin lesions in a mouse model, indicating that lack of Scl1 adhesin promotes bacterial spread over localized infection. These studies suggest the uniquely evolved scl1 locus in the M3-type strains, which prevents surface expression of the major Scl1 adhesin, contributed to the emergence of the invasive M3-type strains. Furthermore these studies provide insight into the molecular mechanisms mediating colonization, biofilm formation, and pathogenesis of group A streptococci.

Naringin directly activates inwardly rectifying potassium channels at an overlapping binding site to tertiapin-Q

PubMed Central

Yow, Tin T; Pera, Elena; Absalom, Nathan; Heblinski, Marika; Johnston, Graham AR; Hanrahan, Jane R; Chebib, Mary

2011-01-01

BACKGROUND G protein-coupled inwardly rectifying potassium (KIR3) channels are important proteins that regulate numerous physiological processes including excitatory responses in the CNS and the control of heart rate. Flavonoids have been shown to have significant health benefits and are a diverse source of compounds for identifying agents with novel mechanisms of action. EXPERIMENTAL APPROACH The flavonoid glycoside, naringin, was evaluated on recombinant human KIR3.1–3.4 and KIR3.1–3.2 expressed in Xenopus oocytes using two-electrode voltage clamp methods. In addition, we evaluated the activity of naringin alone and in the presence of the KIR3 channel blocker tertiapin-Q (0.5 nM, 1 nM and 3 nM) at recombinant KIR3.1–3.4 channels. Site-directed mutagenesis was used to identify amino acids within the M1–M2 loop of the KIR3.1F137S mutant channel important for naringin's activity. KEY RESULTS Naringin (100 µM) had minimal effect on uninjected oocytes but activated KIR3.1–3.4 and KIR3.1–3.2 channels. The activation by naringin of KIR3.1–3.4 channels was inhibited by tertiapin-Q in a competitive manner. An alanine-scan performed on the KIR3.1F137S mutant channel, replacing one by one aromatic amino acids within the M1–M2 loop, identified tyrosines 148 and 150 to be significantly contributing to the affinity of naringin as these mutations reduced the activity of naringin by 20- and 40-fold respectively. CONCLUSIONS AND IMPLICATIONS These results show that naringin is a direct activator of KIR3 channels and that tertiapin-Q shares an overlapping binding site on the KIR3.1–3.4. This is the first example of a ligand that activates KIR3 channels by binding to the extracellular M1–M2 linker of the channel. PMID:21391982

Effects of Zn Deficiency and Bicarbonate on the Growth and Photosynthetic Characteristics of Four Plant Species

PubMed Central

Zhao, Kuan; Wu, Yanyou

2017-01-01

Calcareous soils are characterized by low nutrient contents, high bicarbonate (HCO3−) content, and high alkalinity. The effects of HCO3− addition under zinc-sufficient (+Zn) and zinc-deficient (−Zn) conditions on the growth and photosynthetic characteristics of seedlings of two Moraceae species (Broussonetia papyrifera and Morus alba) and two Brassicaceae species (Orychophragmus violaceus and Brassica napus) were investigated. These four species were hydroponically grown in nutrient solution with 0 mM Zn (−Zn) or 0.02 mM Zn (+Zn) and 0 mM or 10 mM HCO3−. The photosynthetic response to HCO3− treatment, Zn deficiency, or both varied according to plant species. Of the four species, Broussonetia papyrifera showed the best adaptability to Zn deficiency for both the 0 mM and 10 mM HCO3− treatments due to its strong growth and minimal inhibition of photosynthesis and photosystem II (PS II). Brassica napus was sensitive to Zn deficiency, HCO3− treatment, or both as evidenced by the considerable inhibition of photosynthesis and high PS II activity. The results indicated different responses of various plant species to Zn deficiency and excess HCO3−. Broussonetia papyrifera was shown to have potential as a pioneer species in karst regions. PMID:28076430

Molecular cloning and expression of the calmodulin gene from guinea pig hearts.

PubMed

Feng, Rui; Liu, Yan; Sun, Xuefei; Wang, Yan; Hu, Huiyuan; Guo, Feng; Zhao, Jinsheng; Hao, Liying

2015-06-01

The aim of the present study was to isolate and characterize a complementary DNA (cDNA) clone encoding the calmodulin (CaM; GenBank accession no. FJ012165) gene from guinea pig hearts. The CaM gene was amplified from cDNA collected from guinea pig hearts and inserted into a pGEM®-T Easy vector. Subsequently, CaM nucleotide and protein sequence similarity analysis was conducted between guinea pigs and other species. In addition, reverse transcription-polymerase chain reaction (RT-PCR) was performed to investigate the CaM 3 expression patterns in different guinea pig tissues. Sequence analysis revealed that the CaM gene isolated from the guinea pig heart had ∼90% sequence identity with the CaM 3 genes in humans, mice and rats. Furthermore, the deduced peptide sequences of CaM 3 in the guinea pig showed 100% homology to the CaM proteins from other species. In addition, the RT-PCR results indicated that CaM 3 was widely and differentially expressed in guinea pigs. In conclusion, the current study provided valuable information with regard to the cloning and expression of CaM 3 in guinea pig hearts. These findings may be helpful for understanding the function of CaM3 and the possible role of CaM3 in cardiovascular diseases.

Electrochemical Oxidation of Alkylnitro Compounds PP-1345

DTIC Science & Technology

2004-08-17

to the solution, to deprotonate the methyl group. Figure 22 shows the voltammetric response recorded in a CH3OH /0.2 M Bu4NBF4 solution containing...Voltammogram of Glassy Carbon (GC) Electrode 50 mM TNT/ CH3OH /0.2 M Bu4NBF4/55 mM NaOH 15 The standard redox potential for this reaction was... reaction ). Addition of 100 mM TNT to the basic solution ( CH3OH /0.2 M Bu4NBF4/ 55 mM NaOH) resulted in the appearance of a new oxidation wave with a

Particle-bound polychlorinated dibenzo- p-dioxins and dibenzofurans in the atmosphere of Guangzhou, China

NASA Astrophysics Data System (ADS)

Yu, Liping; Mai, Bixian; Meng, Xiangzhou; Bi, Xinhui; Sheng, Guoying; Fu, Jiamo; Peng, Ping'an

A short-term sampling scheme was devised to determine the levels of particle-bound polychlorinated dibenzo- p-dioxins and dibenzofurans (PCDD/Fs) in Guangzhou atmosphere and to evaluate the impact of PCDD/Fs on the lives of the inhabitants in Guangzhou. Samples were collected from four different districts of Guangzhou City, and the results indicated that industrial activities had tremendous influence on the levels of atmospheric PCDD/Fs in these districts. The mean PCDD/Fs concentrations (mean I-TEQ values) for Huadu, Liwan, Tianhe and Huangpu districts were 3815 fg m -3 (104.6 fg I-TEQ m -3), 12 777 fg m -3 (430.5 fg I-TEQ m -3), 6963 fg m -3 (163.7 fg I-TEQ m -3) and 10 953 fg m -3 (769.3 fg I-TEQ m -3), respectively, which were higher than the concentration ranges for other cities in the world. The mean concentrations of particulate organic carbon (OC) and elemental carbon (EC) were 17.61±0.94 and 3.17±0.21 μg m -3 for Huadu district, 44.18±2.29 and 13.32±0.75 μg m -3 for Liwan district, 33.53±1.72 and 9.89±0.56 μg m -3 for Tianhe district, and 29.52±1.53 and 8.87±0.53 μg m -3 for Huangpu district, respectively. The relationship between PCDD/Fs concentrations and OC and EC concentrations demonstrated that EC could be a better predictor for the concentration of PCDD/Fs. Detailed source analysis indicated that the PCDD/Fs in Guangzhou were derived from small diffuse combustion sources, e.g., traffic sources, domestic burning of fossil fuels, non-industrial combustion sources and industrial combustion sources. Results of daily intake of PCDD/Fs by inhaling air suggested that the inhalation exposure of PCDD/Fs by the inhabitants in Liwan district is relatively high.

Moment rate scaling for earthquakes 3.3 ≤ M ≤ 5.3 with implications for stress drop

NASA Astrophysics Data System (ADS)

Archuleta, Ralph J.; Ji, Chen

2016-12-01

We have determined a scalable apparent moment rate function (aMRF) that correctly predicts the peak ground acceleration (PGA), peak ground velocity (PGV), local magnitude, and the ratio of PGA/PGV for earthquakes 3.3 ≤ M ≤ 5.3. Using the NGA-West2 database for 3.0 ≤ M ≤ 7.7, we find a break in scaling of LogPGA and LogPGV versus M around M 5.3 with nearly linear scaling for LogPGA and LogPGV for 3.3 ≤ M ≤ 5.3. Temporal parameters tp and td—related to rise time and total duration—control the aMRF. Both scale with seismic moment. The Fourier amplitude spectrum of the aMRF has two corners between which the spectrum decays f- 1. Significant attenuation along the raypath results in a Brune-like spectrum with one corner fC. Assuming that fC ≅ 1/td, the aMRF predicts non-self-similar scaling M0∝fC3.3 and weak stress drop scaling Δσ∝M00.091. This aMRF can explain why stress drop is different from the stress parameter used to predict high-frequency ground motion.

Inventory of File sref_em.t09z.pgrb212.ctl.grib2

Science.gov Websites

Temperature [K] 002 10 m above ground UGRD 3 hour fcst U-Component of Wind [m/s] 003 10 m above ground VGRD 3 hour fcst V-Component of Wind [m/s] 004 mean sea level PRMSL 3 hour fcst Pressure Reduced to MSL [Pa mb HGT 3 hour fcst Geopotential Height [gpm] 012 250 mb UGRD 3 hour fcst U-Component of Wind [m/s

Extraction of maxillary first molars improves second and third molar inclinations in Class II Division 1 malocclusion.

PubMed

Livas, Christos; Halazonetis, Demetrios J; Booij, Johan Willem; Katsaros, Christos

2011-09-01

The aim of this study was to assess the changes in inclination of the maxillary second (M2) and third (M3) molars after orthodontic treatment of Class II Division 1 malocclusion with extraction of maxillary first molars. Two groups of subjects were studied. The experimental group consisted of 37 subjects, 18 boys and 19 girls (mean age, 13.2 ± 1.62 years). The inclusion criteria were white origin, Class II Division 1 malocclusion, overjet ≥4 mm, no missing teeth or agenesis, and maxillary M3 present. All patients were treated with extraction of the maxillary first molars and the Begg technique. Standardized lateral cephalometric radiographs were taken at the start of active treatment (T1) and at least 3.7 years posttreatment (T2). The control group was drawn from the archives of the Nittedal Growth Material (Oslo University, Oslo, Norway) and included 54 untreated Class I and Class II subjects,18 boys and 36 girls (mean age, 13.4 ± 1.99 years) followed up for a minimum of 3.6 years. M2 and M3 inclinations relative to the palatal plane (PP) and functional occlusal plane (FOP) were measured and compared between groups and time periods. M2 to PP inclination improved significantly in both the control group (M2-PP at T1, 17.7° ± 5.81°, and at T2, 11.9° ± 4.61°) and the experimental group (M2-PP at T1, 26.7° ± 5.75°, and at T2, 6.9° ± 6.76°). There were also significant increases of the mesial inclination of M3 in the control group (M3-PP at T1, 30.1° ± 8.54°, and at T2, 19.6° ± 9.01°) and extraction group (M3-PP at T1, 32.2° ± 7.90°, and at T2, 12.8° ± 7.36°). By using the FOP as the reference system, no significant change in the inclination of M2 was observed in the control group, whereas, in the extraction group, although more distally inclined at T1, M2 ended up mesially inclined at T2 (M2-FOP at T1, 14.2° ± 4.62°, and at T2, -6.2° ± 6.10°; P <0.0001). M3 inclinations were similar between the groups at T1 (M3-FOP control, 17.3° ± 9.35°; M3-FOP experimental, 19.6° ± 7.37°), and these improved significantly in both groups. However, M3 uprighting was almost 4 times greater in the extraction group (M3-FOP from T2-T1, 5.6° vs 19.9°). The greatest distal inclination of M3 at T2 in the extraction group was 9.4°, a value attained by only 43% of the control group. Extraction of the maxillary first molars in Class II Division 1 patients results in significant uprighting of M2 and M3 and facilitates the normal eruption of M3. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Growth characteristics of primary M7C3 carbide in hypereutectic Fe-Cr-C alloy.

PubMed

Liu, Sha; Zhou, Yefei; Xing, Xiaolei; Wang, Jibo; Ren, Xuejun; Yang, Qingxiang

2016-09-06

The microstructure of the hypereutectic Fe-Cr-C alloy is observed by optical microscopy (OM). The initial growth morphology, the crystallographic structure, the semi-molten morphology and the stacking faults of the primary M7C3 carbide are observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The in-suit growth process of the primary M7C3 carbide was observed by confocal laser microscope (CLM). It is found that the primary M7C3 carbide in hypereutectic Fe-Cr-C alloy is irregular polygonal shape with several hollows in the center and gaps on the edge. Some primary M7C3 carbides are formed by layers of shell or/and consist of multiple parts. In the initial growth period, the primary M7C3 carbide forms protrusion parallel to {} crystal planes. The extending and revolving protrusion forms the carbide shell. The electron backscattered diffraction (EBSD) maps show that the primary M7C3 carbide consists of multiple parts. The semi-molten M7C3 carbide contains unmelted shell and several small-scale carbides inside, which further proves that the primary M7C3 carbide is not an overall block. It is believed that the coalescence of the primary M7C3 carbides is ascribed to the growing condition of the protrusion and the gap filling process.

Growth characteristics of primary M7C3 carbide in hypereutectic Fe-Cr-C alloy

PubMed Central

Liu, Sha; Zhou, Yefei; Xing, Xiaolei; Wang, Jibo; Ren, Xuejun; Yang, Qingxiang

2016-01-01

The microstructure of the hypereutectic Fe-Cr-C alloy is observed by optical microscopy (OM). The initial growth morphology, the crystallographic structure, the semi-molten morphology and the stacking faults of the primary M7C3 carbide are observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The in-suit growth process of the primary M7C3 carbide was observed by confocal laser microscope (CLM). It is found that the primary M7C3 carbide in hypereutectic Fe-Cr-C alloy is irregular polygonal shape with several hollows in the center and gaps on the edge. Some primary M7C3 carbides are formed by layers of shell or/and consist of multiple parts. In the initial growth period, the primary M7C3 carbide forms protrusion parallel to {} crystal planes. The extending and revolving protrusion forms the carbide shell. The electron backscattered diffraction (EBSD) maps show that the primary M7C3 carbide consists of multiple parts. The semi-molten M7C3 carbide contains unmelted shell and several small-scale carbides inside, which further proves that the primary M7C3 carbide is not an overall block. It is believed that the coalescence of the primary M7C3 carbides is ascribed to the growing condition of the protrusion and the gap filling process. PMID:27596718

Isolation, characterization and screening of rhizospheric bacteria of Pittosferum resiniferum Hemsl.

NASA Astrophysics Data System (ADS)

Hanirah, R.; Piakong, M. T.; Syaufi, L.

2015-04-01

The bacterial rhizosphere species of host plant, Petroleum Nut (Pittosferum resiniferum) were isolated and characterized morphologically. The isolates were designated as, TSArp- Cr2, TSArp- Cr3, TSArp- Cr4, TSArp- Cr5, TSArp- Cr6 and TSArp- Cr7. All of the species were tested on three different concentration of phenol (1mM, 3mM and 5mM). Only species TSArp- Cr4 and TSArp- Cr6 growth were detected. The highest growth is 6Log10CFU/ml in 1mM by TSA-Cr4. The lowest reading was 3.6 Log10CFU/ml in 3mM by TSA-Cr6. Species TSArp- Cr4 has higher tolerance on phenol compared to TSArp- Cr6

75 FR 69473 - Sunshine Act Meetings

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-12

... Considered December 2 9 a.m.-9:30 a.m. Welcome and Introductions 9:30 a.m.-1 p.m. Strategic Planning 1 p.m.-3 p.m. Forum Planning 3 p.m.-5 p.m. Report and Discussion on Health Care Reform Working Group December...

Transcription factor Brn-3α mRNA in cancers, relationship with AR, ER receptors and AKT/m-TOR pathway components

NASA Astrophysics Data System (ADS)

Spirina, L. V.; Gorbunov, A. K.; Chigevskaya, S. Y.; Usynin, Y. A.; Kondakova, I. V.; Slonimskaya, E. M.; Usynin, E. A.; Choinzonov, E. L.; Zaitseva, O. S.

2017-09-01

Transcription factors POU4F1 (neurogenic factor Brn-3α) play a pivotal role in cancers development. The aim of the study was to reveal the Brn-3α expression, AR, ER expression in cancers development, association with AKT/mTOR pathway activation. 30 patients with locally advanced prostate cancer, 20 patients with papillary thyroid cancer, T2-3N0-1M0 stages and 40 patients with renal cell cancer T2-3N0M0-1 were involved into the study. The expressions of Brn-3α, AR, ERα, components of AKT/m-TOR signaling pathway genes were performed by real-time PCR. The dependence of Brn-3α expression on mRNA levels of steroid hormone receptors and components of AKT/m-TOR signaling pathway in studied cancers were shown. High levels of mRNA of nuclear factor, steroid hormone receptors were found followed by the activation of this signaling pathway in prostate cancer tissue. The reduction of transcription factor Brn-3α was accompanied with tumor invasive growth with increasing rates of AR, ER and 4E-BP1 mRNA. Thyroid cancer development happened in a case of a Brn-3α and steroid hormone receptors decrease. The activation of AKT/m-TOR signaling pathway was established in the metastatic renal cancers, accompanied with the increase of ER mRNA. But there was no correlation between the steroid receptor and Brn-3α. One-direction changes of Brn-3α were observed in the development of prostate and thyroid cancer due to its effect on the steroid hormone receptors and the activation of AKT/m-TOR signaling pathway components. The influence of this factor on the development of the kidney cancer was mediated through m-TOR activity modifications, the key enzyme of oncogenesis.

Self-association and domain rearrangements between complement C3 and C3u provide insight into the activation mechanism of C3.

PubMed

Li, Keying; Gor, Jayesh; Perkins, Stephen J

2010-10-01

Component C3 is the central protein of the complement system. During complement activation, the thioester group in C3 is slowly hydrolysed to form C3u, then the presence of C3u enables the rapid conversion of C3 into functionally active C3b. C3u shows functional similarities to C3b. To clarify this mechanism, the self-association properties and solution structures of C3 and C3u were determined using analytical ultracentrifugation and X-ray scattering. Sedimentation coefficients identified two different dimerization events in both proteins. A fast dimerization was observed in 50 mM NaCl but not in 137 mM NaCl. Low amounts of a slow dimerization was observed for C3u and C3 in both buffers. The X-ray radius of gyration RG values were unchanged for both C3 and C3u in 137 mM NaCl, but depend on concentration in 50 mM NaCl. The C3 crystal structure gave good X-ray fits for C3 in 137 mM NaCl. By randomization of the TED (thioester-containing domain)/CUB (for complement protein subcomponents C1r/C1s, urchin embryonic growth factor and bone morphogenetic protein 1) domains in the C3b crystal structure, X-ray fits showed that the TED/CUB domains in C3u are extended and differ from the more compact arrangement of C3b. This TED/CUB conformation is intermediate between those of C3 and C3b. The greater exposure of the TED domain in C3u (which possesses the hydrolysed reactive thioester) accounts for the greater self-association of C3u in low-salt conditions. This conformational variability of the TED/CUB domains would facilitate their interactions with a broad range of antigenic surfaces. The second dimerization of C3 and C3u may correspond to a dimer observed in one of the crystal structures of C3b.

A Study of the 3.3 and 3.4 μm Emission Features in Proto-Planetary Nebulae

NASA Astrophysics Data System (ADS)

Hrivnak, Bruce J.; Geballe, T. R.; Kwok, Sun

2007-06-01

Medium-resolution spectra have been obtained of seven carbon-rich proto-planetary nebulae (PPNs) and one young planetary nebula from 3.2 to 3.8 μm, an interval containing the prominent hydrocarbon CH stretches at 3.3 and 3.4 μm due to aromatic and aliphatic structures, respectively. The 3.3 μm feature is newly identified in IRAS 23304+6147, 22223+4327, and 06530-0213 and is confirmed in Z02229+6208. Three of the PPNs emit in the 3.4 μm feature, two of these being new identifications, IRAS 20000+3239 and 01005+7910, with two others showing possible detections. The 3.3 and 3.4 μm emission features in IRAS 22272+5435 are seen in the nebula offset from the star but not at the position of the central star, consistent with the 2003 results of Goto et al. A similar distribution is seen for the 3.3 μm feature in IRAS 22223+4327. All of the PPNs except IRAS 22272+5435 show Class A 3 μm emission features. These observations, when combined with those of the approximately equal number of other carbon-rich PPNs previously observed, demonstrate that there are large differences in the 3 μm emission bands, even for PPNs with central stars of similar spectral type, and thus that the behavior of the bands does not depend solely on spectral type. We also investigated other possible correlations to help explain these differences. These differences do not depend on the C/O value, since the Class B sources fall within the C/O range found for Class A. All of these 3.3 μm sources also show C2 absorption and 21 μm emission features, except IRAS 01005+7910, which is the hottest source at B0. This research is based on observations made at the W. M. Keck Observatory by Gemini staff, supported by the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., on behalf of the international Gemini partnership of Argentina, Australia, Brazil, Canada, Chile, the United Kingdom, and the United States of America. The W. M. Keck Observatory is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

47 CFR 97.305 - Authorized emission types.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Standards see § 97.307(f), paragraph: MF: 160 m Entire band RTTY, data (3). 160 m Entire band Phone, image (1), (2). HF: 80 m Entire band RTTY, data (3), (9). 75 m Entire band Phone, image (1), (2). 40 m 7.000-7.100 MHz RTTY, data (3), (9) 40 m 7.075-7.100 MHz Phone, image (1), (2), (9), (11) 40 m 7.100-7...

76 FR 26182 - Drawbridge Operation Regulations; Hood Canal, WA

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-06

... p.m. to 6 p.m. every day of the week from 3 p.m. May 27, 2011 through 6 p.m. on September 30, 2011... test for both navigation and road traffic. From 3 p.m. to 6 p.m. every day from 3 p.m. on May 27... only five days with more than one opening per day. July 2010 was busier than June. In July 43 openings...

47 CFR 97.305 - Authorized emission types.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Standards see § 97.307(f), paragraph: MF: 160 m Entire band RTTY, data (3). 160 m Entire band Phone, image (1), (2). HF: 80 m Entire band RTTY, data (3), (9). 75 m Entire band Phone, image (1), (2). 60 m 5...), (9) 40 m 7.075-7.100 MHz Phone, image (1), (2), (9), (11) 40 m 7.100-7.125 MHz RTTY, data (3), (9) 40...

47 CFR 97.305 - Authorized emission types.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Standards see § 97.307(f), paragraph: MF: 160 m Entire band RTTY, data (3). 160 m Entire band Phone, image (1), (2). HF: 80 m Entire band RTTY, data (3), (9). 75 m Entire band Phone, image (1), (2). 40 m 7.000-7.100 MHz RTTY, data (3), (9) 40 m 7.075-7.100 MHz Phone, image (1), (2), (9), (11) 40 m 7.100-7...

Qatar Exoplanet Survey : Qatar-3b, Qatar-4b, and Qatar-5b

NASA Astrophysics Data System (ADS)

Alsubai, Khalid; Mislis, Dimitris; Tsvetanov, Zlatan I.; Latham, David W.; Bieryla, Allyson; Buchhave, Lars A.; Esquerdo, Gilbert A.; Bramich, D. M.; Pyrzas, Stylianos; Vilchez, Nicolas P. E.; Mancini, Luigi; Southworth, John; Evans, Daniel F.; Henning, Thomas; Ciceri, Simona

2017-04-01

We report the discovery of Qatar-3b, Qatar-4b, and Qatar-5b, three new transiting planets identified by the Qatar Exoplanet Survey. The three planets belong to the hot Jupiter family, with orbital periods of {P}{{Q}3{{b}}} = 2.50792 days, {P}{{Q}4{{b}}} = 1.80539 days, and {P}{{Q}5{{b}}} = 2.87923 days. Follow-up spectroscopic observations reveal the masses of the planets to be {M}{{Q}3{{b}}} = 4.31 ± 0.47 {M}{{J}}, {M}{{Q}4{{b}}} = 6.10 ± 0.54 {M}{{J}}, and {M}{{Q}5{{b}}} = 4.32 ± 0.18 {M}{{J}}, while model fits to the transit light curves yield radii of {R}{{Q}3{{b}}} = 1.096 ± 0.14 {R}{{J}}, {R}{{Q}4{{b}}} = 1.135 ± 0.11 {R}{{J}}, and {R}{{Q}5{{b}}} = 1.107 ± 0.064 {R}{{J}}. The host stars are low-mass main sequence stars with masses and radii M Q3 = 1.145 ± 0.064 M ⊙, M Q4 = 0.896 ± 0.048 M ⊙, M Q5 = 1.128 ± 0.056 M ⊙ and R Q3 = 1.272 ± 0.14 R ⊙, R Q4 = 0.849 ± 0.063 R ⊙, and R Q5 = 1.076 ± 0.051 R ⊙ for Qatar-3, 4, and 5 respectively. The V magnitudes of the three host stars are V Q3 = 12.88, V Q4 = 13.60, and V Q5 = 12.82. All three new planets can be classified as heavy hot Jupiters (M > 4 M J).

Predictors of coarse particulate matter and associated endotoxin concentrations in residential environments

NASA Astrophysics Data System (ADS)

Bari, Md. Aynul; MacNeill, Morgan; Kindzierski, Warren B.; Wallace, Lance; Héroux, Marie-Ève; Wheeler, Amanda J.

2014-08-01

Exposure to coarse particulate matter (PM), i.e., particles with an aerodynamic diameter between 2.5 and 10 μm (PM10-2.5), is of increasing interest due to the potential for health effects including asthma, allergy and respiratory symptoms. Limited information is available on indoor and outdoor coarse PM and associated endotoxin exposures. Seven consecutive 24-h samples of indoor and outdoor coarse PM were collected during winter and summer 2010 using Harvard Coarse Impactors in a total of 74 Edmonton homes where no reported smoking took place. Coarse PM filters were subsequently analyzed for endotoxin content. Data were also collected on indoor and outdoor temperature, relative humidity, air exchange rate, housing characteristics and occupants' activities. During winter, outdoor concentrations of coarse PM (median = 6.7 μg/m3, interquartile range, IQR = 3.4-12 μg/m3) were found to be higher than indoor concentrations (median 3.4 μg/m3, IQR = 1.6-5.7 μg/m3); while summer levels of indoor and outdoor concentrations were similar (median 4.5 μg/m3, IQR = 2.3-6.8 μg/m3, and median 4.7 μg/m3, IQR = 2.1-7.9 μg/m3, respectively). Similar predictors were identified for indoor coarse PM in both seasons and included corresponding outdoor coarse PM concentrations, whether vacuuming, sweeping or dusting was performed during the sampling period, and number of occupants in the home. Winter indoor coarse PM predictors also included the number of dogs and indoor endotoxin concentrations. Summer median endotoxin concentrations (indoor: 0.41 EU/m3, outdoor: 0.64 EU/m3) were 4-fold higher than winter concentrations (indoor: 0.12 EU/m3, outdoor: 0.16 EU/m3). Other than outdoor endotoxin concentrations, indoor endotoxin concentration predictors for both seasons were different. Winter endotoxin predictors also included presence of furry pets and whether the vacuum had a high efficiency particulate air (HEPA) filter. Summer endotoxin predictors were problems with mice in the previous 12 months and mean indoor relative humidity levels.

40 CFR 174.505 - Bacillus thuringiensis modified Cry3A protein (mCry3A) in corn; exemption from the requirement of...

Code of Federal Regulations, 2010 CFR

2010-07-01

... protein (mCry3A) in corn; exemption from the requirement of a tolerance. 174.505 Section 174.505... thuringiensis modified Cry3A protein (mCry3A) in corn; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis modified Cry3A protein (mCry3A) in corn are exempt from the requirement of...

40 CFR 174.505 - Bacillus thuringiensis modified Cry3A protein (mCry3A) in corn; exemption from the requirement of...

Code of Federal Regulations, 2011 CFR

2011-07-01

... protein (mCry3A) in corn; exemption from the requirement of a tolerance. 174.505 Section 174.505... thuringiensis modified Cry3A protein (mCry3A) in corn; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis modified Cry3A protein (mCry3A) in corn are exempt from the requirement of...

40 CFR 174.505 - Bacillus thuringiensis modified Cry3A protein (mCry3A) in corn; exemption from the requirement of...

Code of Federal Regulations, 2013 CFR

2013-07-01

... protein (mCry3A) in corn; exemption from the requirement of a tolerance. 174.505 Section 174.505... thuringiensis modified Cry3A protein (mCry3A) in corn; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis modified Cry3A protein (mCry3A) in corn are exempt from the requirement of...

40 CFR 174.505 - Bacillus thuringiensis modified Cry3A protein (mCry3A) in corn; exemption from the requirement of...

Code of Federal Regulations, 2012 CFR

2012-07-01

... protein (mCry3A) in corn; exemption from the requirement of a tolerance. 174.505 Section 174.505... thuringiensis modified Cry3A protein (mCry3A) in corn; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis modified Cry3A protein (mCry3A) in corn are exempt from the requirement of...

40 CFR 174.505 - Bacillus thuringiensis modified Cry3A protein (mCry3A) in corn; exemption from the requirement of...

Code of Federal Regulations, 2014 CFR

2014-07-01

... protein (mCry3A) in corn; exemption from the requirement of a tolerance. 174.505 Section 174.505... thuringiensis modified Cry3A protein (mCry3A) in corn; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis modified Cry3A protein (mCry3A) in corn are exempt from the requirement of...

Indoor and Outdoor Levels and Sources of Submicron Particles (PM1) at Homes in Edmonton, Canada.

PubMed

Bari, Md Aynul; Kindzierski, Warren B; Wallace, Lance A; Wheeler, Amanda J; MacNeill, Morgan; Héroux, Marie-Ève

2015-06-02

Exposure to submicron particles (PM1) is of interest due to their possible chronic and acute health effects. Seven consecutive 24-h PM1 samples were collected during winter and summer 2010 in a total of 74 nonsmoking homes in Edmonton, Canada. Median winter concentrations of PM1 were 2.2 μg/m(3) (interquartile range, IQR = 0.8-6.1 μg/m(3)) and 3.3 μg/m(3) (IQR = 1.5-6.9 μg/m(3)) for indoors and outdoors, respectively. In the summer, indoor (median 4.4 μg/m(3), IQR = 2.4-8.6 μg/m(3)) and outdoor (median 4.3 μg/m(3), IQR = 2.6-7.4 μg/m(3)) levels were similar. Positive matrix factorization (PMF) was applied to identify and apportion indoor and outdoor sources of elements in PM1 mass. Nine sources contributing to both indoor and outdoor PM1 concentrations were identified including secondary sulfate, soil, biomass smoke and environmental tobacco smoke (ETS), traffic, settled and mixed dust, coal combustion, road salt/road dust, and urban mixture. Three additional indoor sources were identified i.e., carpet dust, copper-rich, and silver-rich. Secondary sulfate, soil, biomass smoke and ETS contributed more than 70% (indoors: 0.29 μg/m(3), outdoors: 0.39 μg/m(3)) of measured elemental mass in PM1. These findings can aid understanding of relationships between submicron particles and health outcomes for indoor/outdoor sources.

14CO2 dispersion around two PWR nuclear power plants in Brazil.

PubMed

Dias, Cíntia Melazo; Stenström, Kristina; Bacelar Leão, Igor Luiz; Santos, Roberto Ventura; Nícoli, Iêda Gomes; Skog, Göran; Ekström, Peter; da Silveira Corrêa, Rosangela

2009-07-01

Atmospheric air samples were taken within 3 km from power plants encompassing five different distances and wind directions. Samples were taken between 2002 and 2005 aiming to evaluate the environmental (14)C enrichment due to the operation of Brazilian nuclear power plants. The sampling system consisted of a pump connected to a trapping column filled with a 3M NaOH solution. The trapped CO(2) was analyzed for (14)C by using a single stage accelerator mass spectrometry (SSAMS). All sampling sites revealed measurable (14)C excess values. The maximum excesses were of 15 and 14 mBq/m(3) for sampling sites placed at NE of the power plants, which is the main wind direction in the area. The mean excesses values were 12 mBq/m(3) to the NE direction, 8 mBq/m(3) to the E, 10 mBq/m(3) to the N, 8 mBq/m(3) to the WNW and 7 mBq/m(3) to the W direction (increasing distances from NE to W). Compared to other Light Water Reactors (LWR) data, these means' values are significantly higher than the average worldwide reported value of 3 mBq/m(3). Available data indicate that the observed values are not related to (14)C emission by the power plants vent stack. Other factors, such as topography, seem to have an important role because it affects wind dispersion thus favoring (14)C accumulation in the sampled area. Moreover, the high elevations around the power plants enhance the chances to measure high values of (14)C since the plume can be intercepted before it is drawn to the ground. Modeling of the plume has shown that its dispersion does not follow a Gaussian model and that agreement between atmospheric CO(2) and vegetation (14)C activities occurs only for sampling sites placed at NE of the power plants.

Overexpression of variant PNPLA3 gene at I148M position causes malignant transformation of hepatocytes via IL-6-JAK2/STAT3 pathway in low dose free fatty acid exposure: a laboratory investigation in vitro and in vivo

PubMed Central

Liu, Zhengtao; Chen, Tianchi; Lu, Xiaoxiao; Xie, Haiyang; Zhou, Lin; Zheng, Shusen

2016-01-01

Epidemiological survey identified that the variant patatin-like phospholipase domain-containing protein 3 (PNPLA3) gene at I148M position exerts direct effect in promoting hepatocellular carcinoma (HCC) under extraneous oxidative stress by interaction with obesity. However, the mechanism is still unknown. HepG2 cells were overexpressed by transinfection of PNPLA3 with wild-type 148I (PNPLA3WT) and mutant 148M (PNPLA3I148M), respectively. Variation in metabolic indicators, hepatic steatosis, biological behaviors and signaling molecules related to cancer promotion was measured in hepatocytes using low-dose free fatty acid (FFA) exposure. Effect of PNPLA3I148M on xenograft biology and its interaction with dietary obesity were also evaluated in animal study. Cells overexpresssing PNPLA3I148M in low-dose FFA incubation showed more proliferation, migration, invasion, and less apoptosis (P<0.05). Low-dose FFA specifically activated JAK2/STAT3 phosphorylation of PNPLA3I148M cells via upregulation of interleukin-6. Animal study showed high-fat diet accelerated growth of xenografts derived from PNPLA3I148M cells incubated in low-dose FFA. In low oxidative stress, PNPLA3I148M initiated the hepatocyte malignant transformation through the activation of inflammation-mediated JAK/STAT pathway. Dietary obesity amplified the growth of tumor from PNPLA3I148M cells by interaction with local FFA incubation. Anti-inflammation and weight loss might be potential approaches for preventing HCC in high-risk population carrying PNPLA3 variant. PMID:27186262

Overexpression of variant PNPLA3 gene at I148M position causes malignant transformation of hepatocytes via IL-6-JAK2/STAT3 pathway in low dose free fatty acid exposure: a laboratory investigation in vitro and in vivo.

PubMed

Liu, Zhengtao; Chen, Tianchi; Lu, Xiaoxiao; Xie, Haiyang; Zhou, Lin; Zheng, Shusen

2016-01-01

Epidemiological survey identified that the variant patatin-like phospholipase domain-containing protein 3 (PNPLA3) gene at I148M position exerts direct effect in promoting hepatocellular carcinoma (HCC) under extraneous oxidative stress by interaction with obesity. However, the mechanism is still unknown. HepG2 cells were overexpressed by transinfection of PNPLA3 with wild-type 148I (PNPLA3(WT)) and mutant 148M (PNPLA3(I148M)), respectively. Variation in metabolic indicators, hepatic steatosis, biological behaviors and signaling molecules related to cancer promotion was measured in hepatocytes using low-dose free fatty acid (FFA) exposure. Effect of PNPLA3(I148M) on xenograft biology and its interaction with dietary obesity were also evaluated in animal study. Cells overexpresssing PNPLA3(I148M) in low-dose FFA incubation showed more proliferation, migration, invasion, and less apoptosis (P<0.05). Low-dose FFA specifically activated JAK2/STAT3 phosphorylation of PNPLA3(I148M) cells via upregulation of interleukin-6. Animal study showed high-fat diet accelerated growth of xenografts derived from PNPLA3(I148M) cells incubated in low-dose FFA. In low oxidative stress, PNPLA3(I148M) initiated the hepatocyte malignant transformation through the activation of inflammation-mediated JAK/STAT pathway. Dietary obesity amplified the growth of tumor from PNPLA3(I148M) cells by interaction with local FFA incubation. Anti-inflammation and weight loss might be potential approaches for preventing HCC in high-risk population carrying PNPLA3 variant.

Fermion Universality Manifesting Itself in the Dirac Component of Neutrino Mass Matrix

NASA Astrophysics Data System (ADS)

Krolikowski, Wojciech

2002-02-01

An effective texture is presented for six Majorana conventional neutrinos (three active and three sterile), based on a 6× 6 neutrino mixing matrix whose 3× 3 active--active component arises from the popular bimaximal mixing matrix of active neutrinos ν e, ν μ , ν τ by three small rotations in the 14, 25, 36 planes of ν 1 , ν 2 , ν 3 and ν 4 , ν5, ν 6 neutrino mass states. The Dirac component (i.e. , 3 × 3 active-sterile component) of the resulting 6 × 6 neutrino mass matrix is conjectured to get a structure similar to the charged-lepton and quark 3 × 3 mass matrices, after the bimaximal mixing, specific for neutrinos, is transformed out unitarily from the neutrino mass matrix. The charged-lepton and quark mass matrices are taken in a universal form constructed previously by the author with a conside- rable phenomenological success. Then, for the option of m21 ≃ m22 ≃ m23 ≫ m24 ≃ m25 ≃ m26 ≃ 0, the proposed texture predicts oscillations of solar ν e's with Δ m2sol ≡ Δ m221 ˜ (1.1 to 1.2) × 10-5 eV2, not inconsistent with the LMA solar solution, if the SuperKamiokande value Δ m2atm ≡ Δ m232 ˜ (3 to 3.5) × 10-3eV2 for oscillations of atmospheric ν μ 's is taken as an input. Here, sin2 2θ sol ˜ 1 and sin2 2 θ atm ˜ 1. The texture predicts also an LSND effect with sin2 2θ LSND (1.4 to 1.9)× 10-11 (eV/m1)4 and Δ m2LSND ≡ Δ m225 ˜ m21 + (1.1 to 1.2) 10-5 eV}2. Unfortunately, the Chooz experiment imposes on the LSND effect (in our texture) a very small upper bound sin2 2θ LSND ≲ 1.3 × 10-3, which corresponds to the lower limit m1 ≳ (1.0 to 1.1)× 10-2 eV.

Ammunition Cost Research Study. Volume I.

DTIC Science & Technology

1983-01-01

0.048 4,000,000 1.72 1.74 M717 PD 0.25 571,490 8.22 6.13 M567 PD 1.30 300,000 10.43 17.22 M503A2 PD 0.34 814,701 10.64 7.28 M739 PD 1.43 915,837 10.65...M503A2 PD 0.34 252,336 10.73 7.58 M567 PD 1.30 1,071,100 11.23 16.29 M739 PD 1.43 915,837 11.30 17.47 M720 PD 2.10 90,000 11.41 23.46 m567 PD 1.30...14.86 12.91 M524A6 PD 1.27 3,982,150 15.11 13.04 M524A6 PD 1.27 3,181,102 15.44 13.81 M739 PD 1.43 3,168,072 15.47 14.86 M524A6 PD 1.27 3,045,000 17.37

Pharmacological study of the mechanisms involved in the vasodilator effect produced by the acute application of triiodothyronine to rat aortic rings

PubMed Central

Lozano-Cuenca, J.; López-Canales, O.A.; Aguilar-Carrasco, J.C.; Villagrana-Zesati, J.R.; López-Mayorga, R.M.; Castillo-Henkel, E.F.; López-Canales, J.S.

2016-01-01

A relationship between thyroid hormones and the cardiovascular system has been well established in the literature. The present in vitro study aimed to investigate the mechanisms involved in the vasodilator effect produced by the acute application of 10-8–10-4 M triiodothyronine (T3) to isolated rat aortic rings. Thoracic aortic rings from 80 adult male Wistar rats were isolated and mounted in tissue chambers filled with Krebs-Henseleit bicarbonate buffer in order to analyze the influence of endothelial tissue, inhibitors and blockers on the vascular effect produced by T3. T3 induced a vasorelaxant response in phenylephrine-precontracted rat aortic rings at higher concentrations (10-4.5–10-4.0 M). This outcome was unaffected by 3.1×10-7 M glibenclamide, 10-3 M 4-aminopyridine (4-AP), 10-5 M indomethacin, or 10-5 M cycloheximide. Contrarily, vasorelaxant responses to T3 were significantly (P<0.05) attenuated by endothelium removal or the application of 10-6 M atropine, 10-5 M L-NG-nitroarginine methyl ester (L-NAME), 10-7 M 1H-(1,2,4)oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), 10-6 M (9S,10R,12R)-2,3,9,10,11,12-Hexahydro-10-methoxy-2,9-dimethyl-1-oxo-9,12-epoxy-1H-diindolo[1,2,3-fg:3′,2′,1′-kl]pyrrolo[3,4-i](1,6)benzodiazocine-10-carboxylic acid, methyl ester KT 5823, 10-2 M tetraethylammonium (TEA), or 10-7 M apamin plus 10-7 M charybdotoxin. The results suggest the involvement of endothelial mechanisms in the vasodilator effect produced by the acute in vitro application of T3 to rat aortic rings. Possible mechanisms include the stimulation of muscarinic receptors, activation of the NO-cGMP-PKG pathway, and opening of Ca2+-activated K+ channels. PMID:27464023

Determination of gaseous and particulate carbonyls (glycolaldehyde, hydroxyacetone, glyoxal, methylglyoxal, nonanal and decanal) in the atmosphere at Mt. Tai

NASA Astrophysics Data System (ADS)

Kawamura, K.; Okuzawa, K.; Aggarwal, S. G.; Irie, H.; Kanaya, Y.; Wang, Z.

2013-05-01

Gaseous and particulate semi-volatile carbonyl compounds were determined every three hours in the atmosphere of Mount Tai (elevation, 1534 m) in the North China Plain during 2-5, 23-24 and 25 June 2006 under clear sky conditions. Using a two-step filter cartridge in a series, particulate carbonyls were first collected on a quartz filter and then gaseous carbonyls were collected on a quartz filter impregnated with O-benzylhydroxylamine (BHA). After the two-step derivatization with BHA and N,O-Bis(trimethylsilyl)trifluoroacetamide (BSTFA), carbonyl derivatives were measured using a gas chromatography. The gaseous concentrations were obtained as follow: glycolaldehyde (range 0-826 ng m-3, average 303 ng m-3), hydroxyacetone (0-579 ng m-3, 126 ng m-3), glyoxal (46-1200 ng m-3, 487 ng m-3), methylglyoxal (88-2690 ng m-3, 967 ng m-3), n-nonanal (0-500 ng m-3, 89 ng m-3), and n-decanal (0-230 ng m-3, 39 ng m-3). These concentrations are among the highest ever reported in the urban and forest atmosphere. We found that gaseous α-dicarbonyls (glyoxal and methylglyoxal) are more than 20 times more abundant than particulate carbonyls and that glycolaldehyde is one order of magnitude more abundant than in aerosol phase. In contrast, hydroxyacetone and normal aldehydes (nonanal and decanal) are equally present in both phases. Time-resolved variations of carbonyls did not show any a clear diurnal pattern, except for hydroxyacetone. We found that glyoxal, methylglyoxal and glycolaldehyde positively correlated with levoglucosan (a tracer of biomass burning), suggesting that a contribution from field burning of agricultural wastes (wheat crops) is significant for the bifunctional carbonyls in the atmosphere of Mt. Tai. Upward transport of the pollutants to the mountaintop from the low lands in the North China Plain is a major process to control the distributions of carbonyls in the upper atmosphere over Mt. Tai.

Microscale Measurements of Michaelis-Menten Constants of Neuraminidase with Nanogel Capillary Electrophoresis for the Determination of the Sialic Acid Linkage.

PubMed

Gattu, Srikanth; Crihfield, Cassandra L; Holland, Lisa A

2017-01-03

Phospholipid nanogels enhance the stability and performance of the exoglycosidase enzyme neuraminidase and are used to create a fixed zone of enzyme within a capillary. With nanogels, there is no need to covalently immobilize the enzyme, as it is physically constrained. This enables rapid quantification of Michaelis-Menten constants (K M ) for different substrates and ultimately provides a means to quantify the linkage (i.e., 2-3 versus 2-6) of sialic acids. The fixed zone of enzyme is inexpensive and easily positioned in the capillary to support electrophoresis mediated microanalysis using neuraminidase to analyze sialic acid linkages. To circumvent the limitations of diffusion during static incubation, the incubation period is reproducibly achieved by varying the number of forward and reverse passes the substrate makes through the stationary fixed zone using in-capillary electrophoretic mixing. A K M value of 3.3 ± 0.8 mM (V max , 2100 ± 200 μM/min) was obtained for 3'-sialyllactose labeled with 2-aminobenzoic acid using neuraminidase from Clostridium perfringens that cleaves sialic acid monomers with an α2-3,6,8,9 linkage, which is similar to values reported in the literature that required benchtop analyses. The enzyme cleaves the 2-3 linkage faster than the 2-6, and a K M of 2 ± 1 mM (V max , 400 ± 100 μM/min) was obtained for the 6'-sialyllactose substrate. An alternative neuraminidase selective for 2-3 sialic acid linkages generated a K M value of 3 ± 2 mM (V max , 900 ± 300 μM/min) for 3'-sialyllactose. With a knowledge of V max , the method was applied to a mixture of 2-3 and 2-6 sialyllactose as well as 2-3 and 2-6 sialylated triantennary glycan. Nanogel electrophoresis is an inexpensive, rapid, and simple alternative to current technologies used to distinguish the composition of 3' and 6' sialic acid linkages.

RORγt antagonist suppresses M3 muscarinic acetylcholine receptor-induced Sjögren's syndrome-like sialadenitis.

PubMed

Tahara, M; Tsuboi, H; Segawa, S; Asashima, H; Iizuka-Koga, M; Hirota, T; Takahashi, H; Kondo, Y; Matsui, M; Matsumoto, I; Sumida, T

2017-02-01

We showed recently that M3 muscarinic acetylcholine receptor (M3R)-reactive CD3 + T cells play a pathogenic role in the development of murine autoimmune sialadenitis (MIS), which mimics Sjögren's syndrome (SS). The aim of this study was to determine the effectiveness and mechanism of action of retinoic acid-related orphan receptor-gamma t (RORγt) antagonist (A213) in MIS. Splenocytes from M3R knockout (M3R -/- ) mice immunized with murine M3R peptide mixture were inoculated into recombination-activating gene 1 knockout (Rag-1 -/- ) mice (M3R -/- →Rag-1 -/- ) with MIS. Immunized M3R -/- mice (pretransfer treatment) and M3R -/- →Rag-1 -/- mice (post-transfer treatment) were treated with A213 every 3 days. Salivary volume, severity of sialadenitis and cytokine production from M3R peptide-stimulated splenocytes and lymph node cells were examined. Effects of A213 on cytokine production were analysed by enzyme-linked immunosorbent assay (ELISA) and on T helper type 1 (Th1), Th17 and Th2 differentiation from CD4 + T cells by flow cytometry. Pretransfer A213 treatment maintained salivary volume, improved MIS and reduced interferon (IFN)-γ and interleukin (IL)-17 production significantly compared with phosphate-buffered saline (PBS) (P < 0·05). These suppressive effects involved CD4 + T cells rather than CD11c + cells. Post-transfer treatment with A213 increased salivary volume (P < 0·05), suppressed MIS (P < 0·005) and reduced IFN-γ and IL-17 production (P < 0·05). In vitro, A213 suppressed IFN-γ and IL-17 production from M3R-stimulated splenocytes and CD4 + T cells of immunized M3R -/- mice (P < 0·05). In contrast with M3R specific responses, A213 suppressed only IL-17 production from Th17 differentiated CD4 + T cells without any effect on Th1 and Th2 differentiation in vitro. Our findings suggested that RORγt antagonism is potentially suitable treatment strategy for SS-like sialadenitis through suppression of IL-17 and IFN-γ production by M3R-specific T cells. © 2016 British Society for Immunology.

Photoactive bile salts with critical micellar concentration in the micromolar range.

PubMed

Gomez-Mendoza, Miguel; Marin, M Luisa; Miranda, Miguel A

2016-05-14

The aggregation behavior of bile salts is strongly dependent on the number of hydroxyl groups. Thus, cholic acid (CA), with three hydroxyls, starts forming aggregates at 15 mM, while deoxycholic, chenodeoxycholic or ursodeoxycholic acids, with two hydroxyls, start aggregating at 5-10 mM; for lithocholic acid, with only one hydroxyl group, aggregation is observed at lower concentration (2-3 mM). Here, the singular self-assembling properties of dansyl and naproxen derivatives of CA (3β-Dns-CA and 3β-NPX-CA, respectively) have been demonstrated on the basis of their photoactive properties. Thus, the emission spectra of 3β-Dns-CA registered at increasing concentrations (25-140 μM) showed a remarkable non-linear enhancement in the emission intensity accompanied by a hypsochromic shift of the maximum and up to a three-fold increase in the singlet lifetime. The inflection point at around 50-70 μM pointed to the formation of unprecedented assemblies at such low concentrations. In the case of 3β-NPX-CA, when the NPX relative triplet lifetime was plotted against concentration, a marked increase (up to two-fold) was observed at 40-70 μM, indicating the formation of new 3β-NPX-CA assemblies at ca. 50 μM. Additional evidence supporting the formation of new 3β-Dns-CA or 3β-NPX-CA assemblies at 40-70 μM was obtained from singlet excited state quenching experiments using iodide. Moreover, to address the potential formation of hybrid assemblies, 1 : 1 mixtures of 3β-Dns-CA and 3β-NPX-CA (2-60 μM, total concentration) were subjected to steady-state fluorescence experiments, and their behavior was compared to that of the pure photoactive derivatives. A lower increase in the emission was observed for 3β-NPX-CA in the mixture, while a huge increase was experienced by 3β-Dns-CA in the same concentration range (up to 60 μM total). A partial intermolecular energy transfer from NPX to Dns, consistent with their reported singlet energies, was revealed, pointing to the formation of extremely fluorescent hybrid assemblies at 5-10 μM (total concentration). The morphology of the entities was investigated by means of confocal microscopy. At 90 μM, 3β-Dns-CA showed disperse assemblies in the μm range.

Carbachol induces Ca(2+)-dependent contraction via muscarinic M2 and M3 receptors in rat intestinal subepithelial myofibroblasts.

PubMed

Iwanaga, Koichi; Murata, Takahisa; Okada, Muneyoshi; Hori, Masatoshi; Ozaki, Hiroshi

2009-07-01

Intestinal myofibroblasts (IMFs) that exist adjacent to the basement membrane of intestines have contractility and contribute to physical barriers of the intestine. Nerve endings distribute adjacent to IMFs, suggesting neurotransmitters may influence IMFs motility; however, there is no direct evidence showing the interaction. Here, we isolated IMFs from rat colon and investigated the effect of acetylcholine on IMFs contractility. In the collagen gel contraction assay, carbachol (1 - 10 microM) and the muscarinic receptor agonist bethanechol (30 - 300 microM) dose-dependently induced IMFs contraction. Pretreatment with the muscarinic receptor antagonist atropine (1 - 10 nM) inhibited carbachol-induced contraction. In RT-PCR, mRNA expression of all muscarinic receptor subtypes (M(1) - M(5)) was detected in IMFs. Subsequently we found pretreatment with the muscarinic M(2) receptor antagonist 11-([2-[(diethylamino)methyl]-1-piperdinyl]acetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one (AF-DX116) (10 and 30 nM) or the muscarinic M(3) receptor antagonist 4-diphenylacetoxy-N-methyl-piperidine (4-DAMP) (3 and 10 nM) dose-dependently inhibited carbachol-induced contraction. In Ca(2+) measurement, 1 - 10 microM carbachol and 30 - 300 microM bethanechol elevated the intracellular Ca(2+) concentration ([Ca(2+)](i)) in IMFs. Atropine (10 nM) eliminated carbachol-induced [Ca(2+)](i) elevation. The Ca(2+)-channel blocker LaCl(3) (3 microM) abolished carbachol-induced [Ca(2+)](i) elevation and contraction. Furthermore, AF-DX116 and 4-DAMP dose-dependently inhibited the carbachol-induced [Ca(2+)](i) elevation. These observations suggest that acetylcholine elicits Ca(2+)-dependent IMF contraction through muscarinic M(2) and M(3) receptors.

Tripodal polyphosphine ligands as inductors of chelate ring-opening processes in mononuclear palladium(II) and platinum(II) compounds. The X-ray crystal structure of two derivatives containing dangling phosphorus.

PubMed

Fernández-Anca, Damián; García-Seijo, M Inés; García-Fernández, M Esther

2010-03-07

The reaction of NP(3) (tris[2-(diphenylphosphino)ethyl]amine and PP(3) (tris[2-(diphenylphosphino)ethyl]phosphine) with the five-coordinate complexes [PdCl(NP(3))]Cl (1) and [MX(PP(3))]X [M = Pd: X = Cl(2), Br(3), I(4); M = Pt: X = Cl(5), Br(6), I(7)], respectively, followed by (31)P{(1)H}NMR when X = Cl, led to the formation of unprecedented four-coordinate halides in a 1 : 2 metal to ligand ratio, [M(AP(3))(2)]X(2) [A = N, M = Pd: X = Cl(8); A = P, M = Pd: X = Cl(9), Br(10), I(11); A = P, M = Pt: X = Cl(12), Br(13), I (14)], containing reactive dangling phosphorus. Given the non characterised precursors [M(ONO(2))(PP(3))](NO(3))], the interaction between the heteronuclear species [MAg(NO(3))(3)(PP(3))] [M = Pd(15), Pt(16)] and PP(3) was explored. It was found that the addition of 1 equivalent of phosphine afforded [MAg(NO(3))(PP(3))(2)](NO(3))(2) [M = Pd(15*), Pt(16*)] containing Ag(I) bound to two dangling phosphorus while the reaction with 2 equivalents led to the complexes [M(PP(3))(2)](NO(3))(2) [M = Pd (17), Pt (18)] in coexistence with [Ag(2)(mu-PP(3))(2)](NO(3))(2). The fate of Ag(I) on the reaction of the mixed metal compounds with excess PP(3) consisted of preventing dissociation, observed in solution for halides, and acting as an assistant for crystallization. Colourless single crystals of 18 and 10, studied by X-ray diffraction, were afforded by reaction of 16 with 4 equivalents of PP(3) and from solutions of 10 in chloroform coexisting with red crystals of 3, respectively. The structures revealed the presence of dications [M(PP(3))(2)](2+) that show two five-membered chelate rings to M(II) in a square-planar arrangement and four uncoordinated phosphine arms with the counter anions being symmetrically placed at 4.431 (Br(-)) and 13.823 (NO(3)(-)) A from M(II) above and below its coordination, MP(4), plane. Complexes 9 and 12 were shown to undergo an interesting reactivity in solution versus group 11 monocations. The reactions consisted of conversions of the two five-membered chelate rings to M into three (structure I) or two (structure II) fused five-membered chelate rings, formation of species where Pt(II) retained its square-planar environment with the two dangling phosphine arms of each PP(3) bound to Cu(I) or Ag(I) (structure III) and complexes bearing distorted square-planar (P(2)MCl(2)) and presumably tetrahedral (AuP(4)+ P(2)AuCl(2)) arrangements (structure IV). The processes with Ag(I) salts also gave mixtures of I+III (chloride and nitrate) or II+III (nitrate).

Nonimpacted Third Molars Affect the Periodontal Status of Adjacent Teeth: A Cross-Sectional Study.

PubMed

Li, Zhi-Bang; Qu, Hong-Lei; Zhou, Li-Na; Tian, Bei-Min; Gao, Li-Na; Chen, Fa-Ming

2017-07-01

Most previous studies of the effect of third molars (M3s) on the health of adjacent second molars (A-M2s) have focused on impacted M3s (I-M3s). The purpose of this study was to investigate whether nonimpacted M3 (N-M3s) could affect the periodontal status of A-M2s. In this cross-sectional study, patients (≥18 years) who had at least 1 quadrant with intact first and second molars and a nonimpacted or absent M3 were enrolled in this study. The periodontal measurements of M2 (6 sites) in the examined quadrants included the gingival index (GI), plaque index (PLI), probing pocket depth (PPD), clinical attachment level (CAL), gingival recession, and bleeding on probing (BOP). The mean GI, PLI, PPD, CAL, and BOP proportion and the proportion with at least 1 site with a PPD of at least 5 mm (PPD5 + ) were compared using the t test or χ 2 test. The association of PPD5 + (percentage) or BOP (percentage) with the presence of N-M3s was assessed using a 2-level logistic regression model (quadrant-based analysis). One hundred thirty-five patients (43.7% men; 40.6 ± 11.5 yr old) were enrolled in this study. Patients who had at least 1 quadrant with 3 intact molars and an N-M3 were enrolled in group A (105 patients), and patients who had at least 1 quadrant with intact first and second molars without an M3 were enrolled in group B (30 patients). The periodontal parameters (ie, GI, PLI, PPD, CAL, BOP, and PPD5 + ) were markedly greater in group A. When other factors associated with periodontal disease were controlled, N-M3s were associated with the PPD5 + (odds ratio = 6.7) and BOP (odds ratio = 4.0) of the A-M2s. Other factors positively associated with A-M2 PPD5 + were location on the mandible, age older than 35 years, and smoking. The presence of N-M3s is a potential risk factor for the development of periodontitis in A-M2s. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Effects of W on microstructure of as-cast 28 wt.%Cr–2.6 wt.%C–(0–10)wt.%W irons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Imurai, S.; Thanachayanont, C.; Pearce, J.T.H.

2015-01-15

Microstructures of as-cast 28 wt.%Cr–2.6 wt.%C irons containing (0–10)wt.%W with the Cr/C ratio about 10 were studied and related to their hardness. The experimental irons were cast into dry sand molds. Microstructural investigation was performed by light microscopy, X-ray diffractometry, scanning electron microscopy, transmission electron microscopy and energy-dispersive X-ray spectrometry. It was found that the irons with 1 to 10 wt.%W addition was hypereutectic containing large primary M{sub 7}C{sub 3}, whereas the reference iron without W addition was hypoeutectic. The matrix in all irons was austenite, partly transformed to martensite during cooling. The volume fractions of primary M{sub 7}C{sub 3}more » and the total carbides increased, but that of eutectic carbides decreased with increasing the W content of the irons. W addition promoted the formation of W-rich M{sub 7}C{sub 3}, M{sub 6}C and M{sub 23}C{sub 6}. At about 4 wt.%W, two eutectic carbides including M{sub 7}C{sub 3} and M{sub 6}C were observed together with primary M{sub 7}C{sub 3}. At 10 wt.%W, multiple carbides including primary M{sub 7}C{sub 3}, fish-bone M{sub 23}C{sub 6}, and M{sub 6}C were observed. M{sub x}C where x = 3 or less has not been found due possibly to the high M/C ratio in the studied irons. W distribution to all carbides has been determined increasing from ca. 0.3 to 0.8 in mass fraction as the W content in the irons was increased. W addition led to an increase in Vickers macro-hardness of the irons up to 671 kgf/(mm){sup 2} (HV30/15) obtained from the iron with 10 wt.%W. The formation of primary M{sub 7}C{sub 3} and aggregates of M{sub 6}C and M{sub 23}C{sub 6} were the main reasons for hardness increase, indicating potentially improved wear performance of the as-cast irons with W addition. - Highlights: • W addition at 1 up to 10 wt.%W to Fe–28Cr–2.6C produced “hypereutectic” structure. • W addition promoted the formation of W-rich M{sub 7}C{sub 3}, M{sub 6}C and M{sub 23}C{sub 6}. • M{sub 23}C{sub 6} has higher Fe/Cr and W/Cr atm% ratios than those in M{sub 7}C{sub 3}. • Si content and high W content over about 11 atm% are characteristics of M{sub 6}C. • Primary M{sub 7}C{sub 3} and aggregates of M{sub 6}C and M{sub 23}C{sub 6} increased the alloy macro-hardness.« less

METABOLISM AND DOSIMETRY OF VINCLOZOLIN IN RAT

EPA Science Inventory

Vinclozolin (V) is an agricultural fungicide. V administered to rats is hydrolyzed to 2-[[(3,5-dichlorophenyl)-carbamoyl]oxy]-2-methyl-3-butenoic acid (M1) and 3',5'-dichloro-2-hydroxy-2-methylbut-3-enanilide (M2). V, M1and M2 are antiandrogenic by interacting with the androgen r...

The State of Ambient Air Quality in Two Ugandan Cities: A Pilot Cross-Sectional Spatial Assessment.

PubMed

Kirenga, Bruce J; Meng, Qingyu; van Gemert, Frederik; Aanyu-Tukamuhebwa, Hellen; Chavannes, Niels; Katamba, Achilles; Obai, Gerald; van der Molen, Thys; Schwander, Stephan; Mohsenin, Vahid

2015-07-15

Air pollution is one of the leading global public health risks but its magnitude in many developing countries' cities is not known. We aimed to measure the concentration of particulate matter with aerodynamic diameter <2.5 µm (PM2.5), nitrogen dioxide (NO2), sulfur dioxide (SO2), and ozone (O3) pollutants in two Ugandan cities (Kampala and Jinja). PM2.5, O3, temperature and humidity were measured with real-time monitors, while NO2 and SO2 were measured with diffusion tubes. We found that the mean concentrations of the air pollutants PM2.5, NO2, SO2 and O3 were 132.1 μg/m3, 24.9 µg/m3, 3.7 µg/m3 and 11.4 μg/m3, respectively. The mean PM2.5 concentration is 5.3 times the World Health Organization (WHO) cut-off limits while the NO2, SO2 and O3 concentrations are below WHO cut-off limits. PM2.5 levels were higher in Kampala than in Jinja (138.6 μg/m3 vs. 99.3 μg/m3) and at industrial than residential sites (152.6 μg/m3 vs. 120.5 μg/m3) but residential sites with unpaved roads also had high PM2.5 concentrations (152.6 μg/m3). In conclusion, air pollutant concentrations in Kampala and Jinja in Uganda are dangerously high. Long-term studies are needed to characterize air pollution levels during all seasons, to assess related public health impacts, and explore mitigation approaches.

PNPLA3 mediates hepatocyte triacylglycerol remodeling.

PubMed

Ruhanen, Hanna; Perttilä, Julia; Hölttä-Vuori, Maarit; Zhou, You; Yki-Järvinen, Hannele; Ikonen, Elina; Käkelä, Reijo; Olkkonen, Vesa M

2014-04-01

The I148M substitution in patatin-like phospholipase domain containing 3 (PNPLA3(I148M)) determines a genetic form of nonalcoholic fatty liver disease. To elucidate the mode of PNPLA3 action in human hepatocytes, we studied effects of WT PNPLA3 (PNPLA3(WT)) and PNPLA3(I148M) on HuH7 cell lipidome after [(13)C]glycerol labeling, cellular turnover of oleic acid labeled with 17 deuterium atoms ([D17]oleic acid) in triacylglycerols (TAGs), and subcellular distribution of the protein variants. PNPLA3(I148M) induced a net accumulation of unlabeled TAGs, but not newly synthesized total [(13)C]TAGs. Principal component analysis (PCA) revealed that both PNPLA3(WT) and PNPLA3(I148M) induced a relative enrichment of TAGs with saturated FAs or MUFAs, with concurrent enrichment of polyunsaturated phosphatidylcholines. PNPLA3(WT) associated in PCA with newly synthesized [(13)C]TAGs, particularly 52:1 and 50:1, while PNPLA3(I148M) associated with similar preexisting TAGs. PNPLA3(WT) overexpression resulted in increased [D17]oleic acid labeling of TAGs during 24 h, and after longer incubations their turnover was accelerated, effects not detected with PNPLA3(I148M). PNPLA3(I148M) localized more extensively to lipid droplets (LDs) than PNPLA3(WT), suggesting that the substitution alters distribution of PNPLA3 between LDs and endoplasmic reticulum/cytosol. This study reveals a function of PNPLA3 in FA-selective TAG remodeling, resulting in increased TAG saturation. A defect in TAG remodeling activity likely contributes to the TAG accumulation observed in cells expressing PNPLA3(I148M).

Antitumor effect of CXCR4 antagonist AMD3100 on the tumorigenic cell line of BHP10-3 papillary thyroid cancer cells.

PubMed

Jung, Young Ho; Lee, Doh Young; Cha, Wonjae; Kim, Bo Hae; Sung, Myung-Whun; Kim, Kwang Hyun; Ahn, Soon-Hyun

2016-10-01

A tumorigenic cell line (BHP10-3M) derived from nontumorigenic papillary thyroid carcinoma (PTC) cells (BHP10-3) having rearranged during transfection (RET)/PTC1 gene rearrangement might have a higher expression of CXCR4, either quantitatively or functionally. The authors also postulated that CXCR4-mediated invasion or tumorigenesis could be blocked by CXCR4 antagonists, including AMD3100. The expression of CXCR4 in BHP10-3 and BHP10-3M cells was assessed using immunoblot analysis, flow cytometry, and quantitative reverse-transcriptase polymerase chain reaction (RT-PCR). The effect of AMD3100 on BHP10-3 and BHP10-3M cell lines was evaluated using cell proliferation assay, invasion assay, and tumor growth experiment in nude mice. Immunoblotting, flow cytometry, and quantitative RT-PCR proved that BHP10-3M cells expressed a higher level of CXCR4 than BHP10-3 cells. Although blocking CXCR4 with AMD3100 did not suppress cell proliferation in both cell lines from 1 ng/mL to 100 ng/mL concentration, AMD3100 suppressed invasion of BHP10-3M cells in vitro in a dose-dependent manner. At higher concentrations from 10(3) ng/mL to 10(5) ng/mL, the proliferation of BHP10-3M cells was inhibited more strongly by AMD3100 than that of BHP10-3 cells. Intraperitoneal injection of AMD3100 inhibited tumor formation by BHP10-3M cells in the thyroid of nude mice. A tumorigenic cell line (BHP10-3M) of PTC showed higher expression of CXCR4 quantitatively and functionally than a nontumorigenic cell line (BHP10-3). The CXCR4 antagonist (AMD3100) showed a significant antitumor effect on the tumorigenic cell line of PTC BHP10-3 cells both in vitro and in vivo. CXCR4 antagonist can be expected to have an adjuvant role in the management of PTC. © 2016 Wiley Periodicals, Inc. Head Neck, 2016 © 2016 Wiley Periodicals, Inc. Head Neck 38: First-1486, 2016. © 2016 Wiley Periodicals, Inc.

Snake venomics and venom gland transcriptomic analysis of Brazilian coral snakes, Micrurus altirostris and M. corallinus.

PubMed

Corrêa-Netto, Carlos; Junqueira-de-Azevedo, Inácio de L M; Silva, Débora A; Ho, Paulo L; Leitão-de-Araújo, Moema; Alves, Maria Lúcia M; Sanz, Libia; Foguel, Débora; Zingali, Russolina Benedeta; Calvete, Juan J

2011-08-24

The venom proteomes of Micrurus altirostris and M. corallinus were analyzed by combining snake venomics and venom gland transcriptomic surveys. In both coral snake species, 3FTx and PLA(2) were the most abundant and diversified toxin families. 33 different 3FTxs and 13 PLA(2) proteins, accounting respectively for 79.5% and 13.7% of the total proteins, were identified in the venom of M. altirostris. The venom of M. corallinus comprised 10 3FTx (81.7% of the venom proteome) and 4 (11.9%) PLA(2) molecules. Transcriptomic data provided the full-length amino acid sequences of 18 (M. altirostris) and 10 (M. corallinus) 3FTxs, and 3 (M. altirostris) and 1 (M. corallinus) novel PLA(2) sequences. In addition, venom from each species contained single members of minor toxin families: 3 common (PIII-SVMP, C-type lectin-like, L-amino acid oxidase) and 4 species-specific (CRISP, Kunitz-type inhibitor, lysosomal acid lipase in M. altirostris; serine proteinase in M. corallinus) toxin classes. The finding of a lipase (LIPA) in the venom proteome and in the venom gland transcriptome of M. altirostris supports the view of a recruitment event predating the divergence of Elapidae and Viperidae more than 60 Mya. The toxin profile of both M. altirostris and M. corallinus venoms points to 3FTxs and PLA(2) molecules as the major players of the envenoming process. In M. altirostris venom, all major, and most minor, 3FTxs display highest similarity to type I α-neurotoxins, suggesting that these postsynaptically acting toxins may play the predominant role in the neurotoxic effect leading to peripheral paralysis, respiratory arrest, and death. M. corallinus venom posesses both, type I α-neurotoxins and a high-abundance (26% of the venom proteome) protein of subfamily XIX of 3FTxs, exhibiting similarity to bucandin from Malayan krait, Bungarus candidus, venom, which enhances acetylcholine release presynaptically. This finding may explain the presynaptic neurotoxicity of M. corallinus venom and the lack of this effect in M. altirostris venom. The anti-Micrurus (corallinus and frontalis) antivenom produced by Instituto Butantan quantitatively immunodepleted the minor toxins from M. altirostris and M. corallinus venoms but showed impaired crossreactivity towards their major 3FTx and PLA(2) molecules. The structural diversity of 3FTxs among Micrurus sp. may underlay the impaired cross-immunoreactivity of the Butantan antivenom towards M. altirostris and M. corallinus toxins, hampering the possibility to raise an antivenom against a simple venom mixture exhibiting paraspecific neutralization of other Micrurus venoms. Copyright © 2011 Elsevier B.V. All rights reserved.

Lithium protects against methamphetamine-induced neurotoxicity in PC12 cells via Akt/GSK3β/mTOR pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Jintao; Zhu, Dexiao; Zhang, Jing

Methamphetamine (MA) is neurotoxic, especially in dopaminergic neurons. Long-lasting exposure to MA causes psychosis and increases the risk of Parkinson's disease. Lithium (Li) is a known mood stabilizer and has neuroprotective effects. Previous studies suggest that MA exposure decreases the phosphorylation of Akt/GSK3β pathway in vivo, whereas Li facilitates the phosphorylation of Akt/GSK3β pathway. Moreover, GSK3β and mTOR are implicated in the locomotor sensitization induced by psychostimulants and mTOR plays a critical role in MA induced toxicity. However, the effect of MA on Akt/GSK3β/mTOR pathway has not been fully investigated in vitro. Here, we found that MA exposure significantly dephosphorylated Akt/GSK3β/mTOR pathwaymore » in PC12 cells. In addition, Li remarkably attenuated the dephosphorylation effect of MA exposure on Akt/GSK3β/mTOR pathway. Furthermore, Li showed obvious protective effects against MA toxicity and LY294002 (Akt inhibitor) suppressed the protective effects of Li. Together, MA exposure dephosphorylates Akt/GSK3β/mTOR pathway in vitro, while lithium protects against MA-induced neurotoxicity via phosphorylation of Akt/GSK3β/mTOR pathway. - Highlights: • Lithium protects against methamphetamine-induced neurotoxicity in vitro. • Methamphetamine exposure dephosphorylates Akt/GSK3β/mTOR pathway. • Lithium attenuates methamphetamine-induced toxicity via phosphorylating Akt/GSK3β/mTOR pathway.« less

A theoretical study of the positive and dipositive ions of M(NH3)n and M(H2O)n for M = Mg, Ca, or Sr

NASA Technical Reports Server (NTRS)

Bauschlicher, Charles W., Jr.; Sodupe, Mariona; Partridge, Harry

1992-01-01

The structure and binding energies are determined for many of the M(H2O)n(+) and M(H2O)n(2+) species, for n = 1-3 and M = Mg, Ca, or Sr. The trends are explained in terms of metal sp or sd-sigma hybridization and core polarization. The M(NH3)n(+) systems, with M = Mg or Sr, are also studied. For the positive ions, the low-lying excited states are also studied and compared with experiment. The calculations suggest an alternative interpretation of the SrNH3(+) spectrum.

Ternary metal-rich sulfide with a layered structure

DOEpatents

Franzen, Hugo F.; Yao, Xiaoqiang

1993-08-17

A ternary Nb-Ta-S compound is provided having the atomic formula, Nb.sub.1.72 Ta.sub.3.28 S.sub.2, and exhibiting a layered structure in the sequence S-M3-M2-M1-M2-M3-S wherein S represents sulfur layers and M1, M2, and M3 represent Nb/Ta mixed metal layers. This sequence generates seven sheets stacked along the [001] direction of an approximate body centered cubic crystal structure with relatively weak sulfur-to-sulfur van der Waals type interactions between adjacent sulfur sheets and metal-to-metal bonding within and between adjacent mixed metal sheets.

M2-F3 on lakebed

NASA Image and Video Library

1970-06-19

The M2-F3 Lifting Body is seen here on the lakebed next to the NASA Flight Research Center (later the Dryden Flight Research Center), Edwards, California. Redesigned and rebuilt from the M2-F2, the M2-F3 featured as its most visible change a center fin for greater stability. While the M2-F3 was still demanding to fly, the center fin eliminated the high risk of pilot induced oscillation (PIO) that was characteristic of the M2-F2.

Effects of varying densities on serum reproductive parameters in pen-reared juvenile female rainbow trout Oncorhynchus mykiss farms

NASA Astrophysics Data System (ADS)

Hou, Zhishuai; Wen, Haishen; Li, Jifang; He, Feng; Liu, Qun; Wang, Jinhuan; Guan, Biao; Wang, Qinglong

2017-01-01

The primary goal of this study was to assess the effect of varying densities on serum reproductive parameters of immature rainbow trout Oncorhynchus mykiss. Experimental trout were maintained in intensive, pen-reared farms for 300 days in fresh water reservoirs. Initial densities were 4.6, 6.6, and 8.6 kg/m3 (40, 60, 80 ind./m3), indicated as SD1, SD2, SD3, and final densities were 31.1, 40.6, 49.3 kg/m3, respectively. A summary of the ovarian stages were observed by histological examination. Serum E2 (estradiol), T (testosterone) were evaluated by radioimmunoassay and FSH (follicle-stimulating-hormone), LH (luteinizing-hormone), vitellogenin, 17α,20β-P (17α,20βdihydroxy4-pregnen-3-one) were measured by enzyme-linked immunosorbent assay. Our findings demonstrated that ovarian development were retarded (from stage III to stage IV) at highest rearing density (SD3) after 180 days of intensive culture (over 40.6 kg/m3). In addition, we observed an inverse relationship between serum reproductive parameters and rearing density. Furthermore, compared to serum reproductive parameters of SD1, E2, T, FSH, vitellogenin, 17α,20β-P, GSI and LH of two higher density groups decreased firstly and significantly at 60 (over 15.9 kg/m 3 ), 180 (over 31.7 kg/m 3 ), 180 (over 40.6 kg/m3), 240 (over 36 kg/m3), 240 (over 36 kg/m3), 240 (over 45 kg/m3) and 300 (over 49.3 kg/m3) days, respectively. Comparing serum reproductive parameters within the same ovarian development stage of rainbow trout from varying densities revealed that higher population density also led to significantly lower overall serum reproductive parameters. Overall, this study presents the reproductive, endocrinological parameters of juvenile female rainbow trout at high rearing densities and indicates the need for rainbow trout (114.44±5.21 g, 19.69±0.31 cm) that are initially stocked at 6.6 or 8.6 kg/m3 should be classified and subdivided into lower density after 180 days of farming (not over 31.7 kg/m3).

Sex specificity of behavioral dominance and fasting endurance in wintering canvasbacks: Experimental results

USGS Publications Warehouse

Perry, M.C.; Nichols, J.D.; Conroy, M.J.; Obrecht, H.H.; Williams, B.K.; Weller, Milton W.

1988-01-01

Hand-reared canvasbacks (Aythya valisineria) of varying sex ratios were maintained in pens during winter 1980-81 (3M-3F, 6M-0F, 0M-6F) and winter 1981-82 (4M-2F, 2M-4F) and fed two diets (control and stress). They were observed during feeding trials to determine intrasexual and intersexual aggressive activity. There was little evidence that either diet or sex ratio affected the total number of aggressive encounters. Females fed both control and stress diets were more aggressive and spent more time in the small feeding areas than males in pens with 3M-3F, 4M-2F, and 2M-4F sex ratios. Stressed ducks tended to weigh less than controls throughout the study. Females in the 3M-3F and 4M-2F pens weighed less than those in the 0M-6F and 2M-4F pens, respectively. However, relative weight changes throughout the winter were similar for males and females. Thus, results of these experiments do not lead to conclusive rejection of either the behavioral dominance hypothesis or the fasting endurance hypothesis.

Graphene-metallic nanocomposites as modifiers in electrochemical glucose biosensor transducers

NASA Astrophysics Data System (ADS)

Altuntas, Derya Bal; Tepeli, Yudum; Anik, Ulku

2016-09-01

Graphene sheets and three different graphene-metallic nanocomposites including graphene-copper (graphene-Cu), graphene-nickel (graphene-Ni) and graphene-platinum (graphene-Pt) were prepared and characterized in the first place. Then the electrochemical performances of these nanocomposites were tested in glucose biosensor transducers, which were formed by combining these metallic nanocomposites with glucose oxidase enzyme and glassy carbon paste electrode (GCPE). This is the first work that includes the usage of these graphene-Me nanocomposites as a part of glucose biosensor transducer. Fabricated amperometric biosensors linear ranges were obtained as follow: For the plain graphene, the linear range was found in the concentration range between 50 μM and 800 μM with the RSD (n = 3 for 50 μM glucose) value of 12.86% and LOD value of 7.2 μM. For graphene-Pt modified glucose biosensor, the linear range was between 10 μM and 600 μM with the RSD (n = 3 for 50 μM glucose) value of 3.45% and LOD value of 3.06 μM. In the case of graphene-Ni modified glucose biosensor, the values were 25 μM to 600 μM with the RSD (n = 3 for 50 μM glucose) value of 8.76% and LOD value of 24.71 μM and for graphene-Cu modified glucose biosensor linear range was 25 μM to 400 μM with the RSD (n = 3 for 50 μM glucose) value of 3.93% and LOD value of 2.87 μM.

Sources and production of organic aerosol in Mexico City: insights from the combination of a chemical transport model (PMCAMx-2008) and measurements during MILAGRO

NASA Astrophysics Data System (ADS)

Tsimpidi, A. P.; Karydis, V. A.; Zavala, M.; Lei, W.; Bei, N.; Molina, L.; Pandis, S. N.

2010-11-01

Urban areas are large sources of organic aerosols and their precursors. Nevertheless, the contributions of primary (POA) and secondary organic aerosol (SOA) to the observed particulate matter levels have been difficult to quantify. In this study the three-dimensional chemical transport model PMCAMx-2008 is used to investigate the temporal and geographic variability of organic aerosol in the Mexico City Metropolitan Area (MCMA) during the MILAGRO campaign that took place in the spring of 2006. The organic module of PMCAMx-2008 is based on the volatility basis-set approach: both primary and secondary organic components are assumed to be semi-volatile and photochemically reactive and are distributed in logarithmically spaced volatility bins. The MCMA emission inventory is modified and the POA emissions are distributed by volatility based on dilution experiments. The model predictions are compared with observations from four different types of sites, an urban (T0), a suburban (T1), a rural (T2), and an elevated site in Pico Tres Padres (PTP). The performance of the model in reproducing organic mass concentrations in these sites was encouraging. The average predicted PM1 OA concentration in T0, T1, and T2 was 18 μg m-3, 11.7 μg m-3, and 10.5 μg m-3 respectively, while the corresponding measured values were 17.2 μg m-3, 11 μg m-3, and 9 μg m-3. The average predicted fresh primary OA concentrations were 4.4 μg m-3 at T0, 1.2 μg m-3 at T1 and 1.7 μg m-3 at PTP in reasonably good agreement with the corresponding PMF analysis estimates based on the AMS observations of 4.5, 1.3, and 2.9 μg m-3 respectively. The model reproduced reasonably well the average oxygenated OA (OOA) levels in T0 (7.5 μg m-3 predicted versus 7.5 μg m-3 measured), in T1 (6.3 μg m-3 predicted versus 4.6 μg m-3 measured) and in PTP (6.6 μg m-3 predicted versus 5.9 μg m-3 measured). Inside Mexico City, the locally produced OA is predicted to be on average 53% fresh primary (POA), 11% semi-volatile (S-SOA) and intermediate volatile (I-SOA) organic aerosol, and 36% traditional SOA from the oxidation of VOCs (V-SOA). The long range transport from biomass burning activities and other sources in Mexico is predicted to contribute on average almost as much as the local sources during the MILAGRO period.

The Genetic Variant I148M in PNPLA3 Is Associated With Increased Hepatic Retinyl-Palmitate Storage in Humans.

PubMed

Kovarova, Marketa; Königsrainer, Ingmar; Königsrainer, Alfred; Machicao, Fausto; Häring, Hans-Ulrich; Schleicher, Erwin; Peter, Andreas

2015-12-01

Previous studies revealed that the common sequence variant I148M in patatin-like phospholipase domain-containing protein 3 (PNPLA3) is associated with liver fat content and liver diseases, but not with insulin resistance. Recent data suggest that the PNPLA3 I148M variant has reduced retinyl-palmitate lipase activity in hepatic stellate cells. We hypothesized that the PNPLA3 I148M variant is associated with elevated retinyl-palmitate storage in human liver as a potential link to the clinical pathology. Design/Setting and Participants: Using HPLC, we quantified the retinoid metabolites in liver tissue extracts obtained from 42 human subjects, including 13 heterozygous and six homozygous carriers of the minor PNPLA3 I148M variant. Retinyl-palmitate is elevated in human livers of homozygous PNPLA3 I148M allele carriers Results: The PNPLA3 I148M variant was associated with a significant increase (1.4-fold) in liver fat. The content of retinyl-palmitate was elevated and the ratio of retinol/retinyl-palmitate was reduced in liver extracts obtained from homozygous PNPLA3 I148M minor allele carriers. In a multivariate model including liver fat content, these differences remained significant independent of liver fat content. The content of the minor retinyl-fatty acid esters was similarly increased in homozygous PNPLA3 I148M carriers. The increased content of hepatic retinyl-palmitate and the reduced ratio of retinol/retinyl-palmitate in PNPLA3 I148M minor allele carriers support in vitro findings of an altered retinyl-palmitate lipase activity. Our results indicate that the PNPLA3 I148M variant is relevant for the retinyl-palmitate content in human liver, providing a possible link to chronic liver disease.

Metabotropic Glutamate2 Receptors Play a Key Role in Modulating Head Twitches Induced by a Serotonergic Hallucinogen in Mice

PubMed Central

Benvenga, Mark J.; Chaney, Stephen F.; Baez, Melvyn; Britton, Thomas C.; Hornback, William J.; Monn, James A.; Marek, Gerard J.

2018-01-01

There is substantial evidence that glutamate can modulate the effects of 5-hydroxytryptamine2A (5-HT2A) receptor activation through stimulation of metabotropic glutamate2/3 (mGlu2/3) receptors in the prefrontal cortex. Here we show that constitutive deletion of the mGlu2 gene profoundly attenuates an effect of 5-HT2A receptor activation using the mouse head twitch response (HTR). MGlu2 and mGlu3 receptor knockout (KO) as well as age-matched ICR (CD-1) wild type (WT) mice were administered (±)1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) and observed for head twitch activity. DOI failed to produce significant head twitches in mGlu2 receptor KO mice at a dose 10-fold higher than the peak effective dose in WT or mGlu3 receptor KO mice. In addition, the mGlu2/3 receptor agonist LY379268, and the mGlu2 receptor positive allosteric modulator (PAM) CBiPES, potently blocked the HTR to DOI in WT and mGlu3 receptor KO mice. Conversely, the mGlu2/3 receptor antagonist LY341495 (10 mg/kg) increased the HTR produced by DOI (3 mg/kg) in mGlu3 receptor KO mice. Finally, the mGlu2 receptor potentiator CBiPES was able to attenuate the increase in the HTR produced by LY341495 in mGlu3 receptor KO mice. Taken together, all of these results are consistent with the hypothesis that that DOI-induced head twitches are modulated by mGlu2 receptor activation. These results also are in keeping with a critical autoreceptor function for mGlu2 receptors in the prefrontal cortex with differential effects of acute vs. chronic perturbation (e.g., constitutive mGlu2 receptor KO mice). The robust attenuation of DOI-induced head twitches in the mGlu2 receptor KO mice appears to reflect the critical role of glutamate in ongoing regulation of 5-HT2A receptors in the prefrontal cortex. Future experiments with inducible knockouts for the mGlu2 receptor and/or selective mGlu3 receptor agonists/PAMs/antagonists could provide an important tools in understanding glutamatergic modulation of prefrontal cortical 5-HT2A receptor function. PMID:29599719

Abdominal fat interacts with PNPLA3 I148M, but not with the APOC3 variant in the pathogenesis of liver steatosis in chronic hepatitis C.

PubMed

Zampino, R; Coppola, N; Cirillo, G; Boemio, A; Pisaturo, M; Marrone, A; Macera, M; Sagnelli, E; Perrone, L; Adinolfi, L E; Miraglia del Giudice, E

2013-08-01

The patatin-like phospholipase domain-containing 3 gene (PNPLA3) and the apolipoprotein C3 gene (APOC3) have been studied in relation to liver steatosis and liver disease outcome. The aim of this study was to evaluate the influence of PNPLA3 p.I148M and APOC3 rs2854116 and rs2854117 polymorphisms on the clinical and histological presentation of chronic hepatitis C in an Italian population and their relationship with viral and anthropometric parameters. Patients with hepatitis C (n = 166) entered the study receiving a clinical, histological, virological and biochemical evaluation. APOC3 (rs2854116 and rs2854117) and PNPLA3 (p.I148M) variants were genotyped. PNPLA3 polymorphisms were associated with liver steatosis, which was significantly higher in patients with p.148I/M (P = 0.034) and p.148M/M (P = 0.004) variants than those homozygous for the PNPLA3 wild type. Excluding patients with HCV genotype 3, the association with liver steatosis and PNPLA3 variants was more marked (p.148I/I genotype vs p.148I/M, P = 0.02, and vs p.148M/M, P = 0.005). The APOC3 polymorphism was not associated with any of the evaluated parameters. Among the interacting factors, BMI and waist circumference correlated with liver steatosis (P = 0.008 and 0.004, respectively). Relationship between waist circumference and liver steatosis was analysed for the different PNPLA3 genotypes. Homozygous 148M patients showed a stronger correlation between waist circumference and steatosis than those carrying the other genotypes (P = 0.0047). In our hepatitis C-infected population, the PNPLA3 polymorphism influenced the development of liver steatosis, but not fibrosis progression. APOC3 polymorphisms had no effect on the development of steatosis and no influence on the PNPLA3 polymorphism. The amount of abdominal fat can increase the association of PNPLA3 p.I148M with liver steatosis. © 2013 John Wiley & Sons Ltd.

Structure and Properties of fac-[Re(I)(CO)3(NTA)](2-) (NTA(3-) = Trianion of Nitrilotriacetic Acid) and fac-[Re(I)(CO)3(L)](n-) Analogues Useful for Assessing the Excellent Renal Clearance of the fac-[(99m)Tc(I)(CO)3(NTA)](2-) Diagnostic Renal Agent.

PubMed

Klenc, Jeffrey; Lipowska, Malgorzata; Abhayawardhana, Pramuditha L; Taylor, Andrew T; Marzilli, Luigi G

2015-07-06

We previously identified two new agents based on the [(99m)Tc(V)O](3+) core with renal clearances in human volunteers 30% higher than that of the widely used clinical tracer (99m)Tc-MAG3 (MAG3(5-) = penta-anion of mercaptoacetyltriglycine). However, renal agents with even higher clearances are needed. More recently, we changed our focus from the [(99m)Tc(V)O](3+) core to the discovery of superior tracers based on the fac-[(99m)Tc(I)(CO)3](+) core. Compared to (99m)Tc-MAG3, fac-[(99m)Tc(I)(CO)3(NTA)](2-) (NTA(3-) = trianion of nitrilotriacetic acid) holds great promise by virtue of its efficient renal clearance via tubular secretion and the absence of hepatobiliary elimination, even in patients with severely reduced renal function. We report here NMR, molecular (X-ray) structure, and solution data on fac-[Re(I)(CO)3(NTA)](2-) with a -CH2CO2(-) dangling monoanionic chain and on two fac-[Re(I)(CO)3(L)](-) analogues with either a -CH2CONH2 or a -CH2CH2OH dangling neutral chain. In these three fac-[Re(I)(CO)3(L)](n-) complexes, the fac-[Re(I)(CO)3(N(CH2CO2)2)](-) moiety is structurally similar and has similar electronic properties (as assessed by NMR data). In reported and ongoing studies, the two fac-[(99m)Tc(I)(CO)3(L)](-) analogues with these neutral dangling chains were found to have pharmacokinetic properties very similar to those of fac-[(99m)Tc(I)(CO)3(NTA)](2-). Therefore, we reach the unexpected conclusion that in fac-[(99m)Tc(I)(CO)3(L)](n-) agents, renal clearance is affected much more than anticipated by features of the core plus the chelate rings (the [(99m)Tc(I)(CO)3(N(CH2CO2)2)](-) moiety) than by the presence of a negatively charged dangling carboxylate chain.

The Choice of Alternative 5' Splice Sites in Influenza Virus M1 mRNA is Regulated by the Viral Polymerase Complex

NASA Astrophysics Data System (ADS)

Shih, Shin-Ru; Nemeroff, Martin E.; Krug, Robert M.

1995-07-01

The influenza virus M1 mRNA has two alternative 5' splice sites: a distal 5' splice site producing mRNA_3 that has the coding potential for 9 amino acids and a proximal 5' splice site producing M2 mRNA encoding the essential M2 ion-channel protein. Only mRNA_3 was made in uninfected cells transfected with DNA expressing M1 mRNA. Similarly, using nuclear extracts from uninfected cells, in vitro splicing of M1 mRNA yielded only mRNA_3. Only when the mRNA_3 5' splice site was inactivated by mutation was M2 mRNA made in uninfected cells and in uninfected cell extracts. In influenza virus-infected cells, M2 mRNA was made, but only after a delay, suggesting that newly synthesized viral gene product(s) were needed to activate the M2 5' splice site. We present strong evidence that these gene products are the complex of the three polymerase proteins, the same complex that functions in the transcription and replication of the viral genome. Gel shift experiments showed that the viral polymerase complex bound to the 5' end of the viral M1 mRNA in a sequence-specific and cap-dependent manner. During in vitro splicing catalyzed by uninfected cell extracts, the binding of the viral polymerase complex blocked the mRNA_3 5' splice site, resulting in the switch to the M2 mRNA 5' splice site and the production of M2 mRNA.

Fatigue and changes of ATP, creatine phosphate, and lactate during the 400-m sprint.

PubMed

Hirvonen, J; Nummela, A; Rusko, H; Rehunen, S; Härkönen, M

1992-06-01

Fatigue during the 400-m sprint was studied by measuring muscle ATP, creatine phosphate (CP), lactate (M-La), and blood lactate (B-La) in six male runners before and after four experimental sprints (100, 200, 300, and 400 m). During the first 100 m, muscle CP decreased from 15.8 +/- 1.7 to 8.3 +/- 0.3 mmol/kg while M-La increased to 3.6 +/- 0.4 mmol/kg. After 200 m the CP had decreased to 6.5 +/- 0.5 mmol/kg and M-La had increased to 8.3 +/- 1.1 mmol/kg. At the end of the 400 meters, ATP and CP concentrations had decreased by 27% and 89%, respectively, and M-La had increased to 17.3 +/- 0.9 mmol/kg. It was concluded that after 200 m the speed of running decreased, although CP was not depleted and lactate concentration was not at maximum level. Complete fatigue occurred when CP stores were depleted and B-La and M-La attained an individual maximum.

The evolution of Brown-York quasilocal energy as due to evolution of Lovelock gravity in a system of M0-branes

NASA Astrophysics Data System (ADS)

Sepehri, Alireza; Rahaman, Farook; Capozziello, Salvatore; Ali, Ahmed Farag; Pradhan, Anirudh

Recently, it has been suggested in [S. Chakraborty and N. Dadhich, Brown-York quasilocal energy in Lanczos-Lovelock gravity and black hole horizons, J. High Energ. Phys. 12 (2015) 003.] that the Brown-York mechanism can be used to measure the quasilocal energy in Lovelock gravity. We have used this method in a system of M0-branes and show that the Brown-York energy evolves in the process of birth and growth of Lovelock gravity. This can help us to predict phenomenological events which are emerged as due to dynamical structure of Lovelock gravity in our universe. In this model, first, M0-branes join each other and form an M3-brane and an anti-M3-branes connected by an M2-brane. This system is named BIon. Universes and anti-universes live on M3-branes and M2 plays the role of wormhole between them. By passing time, M2 dissolves in M3’s and nonlinear massive gravities like Lovelock massive gravity emerges and grows. By closing M3-branes, BIon evolves and wormhole between branes makes a transition to black hole. During this stage, Brown-York energy increases and shrinks to large values at the colliding points of branes. By approaching M3-branes towards each other, the square energy of their system becomes negative and some tachyonic states are produced. To remove these states, M3-branes compact, the sign of compacted gravity changes, anti-gravity is created which leads to getting away of branes from each other. Also, the Lovelock gravity disappears and its energy forms a new M2 between M3-branes. By getting away of branes from each other, Brown-York energy decreases and shrinks to zero.

The decapping activator Edc3 and the Q/N-rich domain of Lsm4 function together to enhance mRNA stability and alter mRNA decay pathway dependence in Saccharomyces cerevisiae.

PubMed

Huch, Susanne; Müller, Maren; Muppavarapu, Mridula; Gommlich, Jessie; Balagopal, Vidya; Nissan, Tracy

2016-10-15

The rate and regulation of mRNA decay are major elements in the proper control of gene expression. Edc3 and Lsm4 are two decapping activator proteins that have previously been shown to function in the assembly of RNA granules termed P bodies. Here, we show that deletion of edc3, when combined with a removal of the glutamine/asparagine rich region of Lsm4 (edc3Δ lsm4ΔC) reduces mRNA stability and alters pathways of mRNA degradation. Multiple tested mRNAs exhibited reduced stability in the edc3Δ lsm4ΔC mutant. The destabilization was linked to an increased dependence on Ccr4-mediated deadenylation and mRNA decapping. Unlike characterized mutations in decapping factors that either are neutral or are able to stabilize mRNA, the combined edc3Δ lsm4ΔC mutant reduced mRNA stability. We characterized the growth and activity of the major mRNA decay systems and translation in double mutant and wild-type yeast. In the edc3Δ lsm4ΔC mutant, we observed alterations in the levels of specific mRNA decay factors as well as nuclear accumulation of the catalytic subunit of the decapping enzyme Dcp2. Hence, we suggest that the effects on mRNA stability in the edc3Δ lsm4ΔC mutant may originate from mRNA decay protein abundance or changes in mRNPs, or alternatively may imply a role for P bodies in mRNA stabilization. © 2016. Published by The Company of Biologists Ltd.

The decapping activator Edc3 and the Q/N-rich domain of Lsm4 function together to enhance mRNA stability and alter mRNA decay pathway dependence in Saccharomyces cerevisiae

PubMed Central

Huch, Susanne; Müller, Maren; Muppavarapu, Mridula; Gommlich, Jessie; Balagopal, Vidya; Nissan, Tracy

2016-01-01

ABSTRACT The rate and regulation of mRNA decay are major elements in the proper control of gene expression. Edc3 and Lsm4 are two decapping activator proteins that have previously been shown to function in the assembly of RNA granules termed P bodies. Here, we show that deletion of edc3, when combined with a removal of the glutamine/asparagine rich region of Lsm4 (edc3Δ lsm4ΔC) reduces mRNA stability and alters pathways of mRNA degradation. Multiple tested mRNAs exhibited reduced stability in the edc3Δ lsm4ΔC mutant. The destabilization was linked to an increased dependence on Ccr4-mediated deadenylation and mRNA decapping. Unlike characterized mutations in decapping factors that either are neutral or are able to stabilize mRNA, the combined edc3Δ lsm4ΔC mutant reduced mRNA stability. We characterized the growth and activity of the major mRNA decay systems and translation in double mutant and wild-type yeast. In the edc3Δ lsm4ΔC mutant, we observed alterations in the levels of specific mRNA decay factors as well as nuclear accumulation of the catalytic subunit of the decapping enzyme Dcp2. Hence, we suggest that the effects on mRNA stability in the edc3Δ lsm4ΔC mutant may originate from mRNA decay protein abundance or changes in mRNPs, or alternatively may imply a role for P bodies in mRNA stabilization. PMID:27543059

A Revolutionary Approach for the Development of Future Ground Combat System Specifications

DTIC Science & Technology

2013-09-01

35 B. PHYSICAL PROPERTIES FOR BLUE AGENTS .............................. 38 1. Bradley M2A3 ...available, Wikipedia. B. PHYSICAL PROPERTIES FOR BLUE AGENTS 1. Bradley M2A3 The main ground combat vehicle for the scenario is the Bradley M2A3 ...Total Men Men per Agent MANA Agents 4 x Bradley M2A3 12 3 4 4 x Bradley infantry 28 1 28 Platoon Abrams SEP M1A2 16 4 4 2 x AH64-D attack

Inventory of File sref_nmb.t03z.pgrb212.ctl.grib2

Science.gov Websites

10 m above ground UGRD 3 hour fcst U-Component of Wind [m/s] ENS=low-res ctl 004 10 m above ground VGRD 3 hour fcst V-Component of Wind [m/s] ENS=low-res ctl 005 mean sea level PRMSL 3 hour fcst 250 mb UGRD 3 hour fcst U-Component of Wind [m/s] ENS=low-res ctl 014 500 mb UGRD 3 hour fcst U

The interaction between foliar GA3 application and arbuscular mycorrhizal fungi inoculation improves growth in salinized tomato (Solanum lycopersicum L.) plants by modifying the hormonal balance.

PubMed

Khalloufi, Mouna; Martínez-Andújar, Cristina; Lachaâl, Mokhtar; Karray-Bouraoui, Najoua; Pérez-Alfocea, Francisco; Albacete, Alfonso

2017-07-01

The agriculture industry is frequently affected by various abiotic stresses limiting plant productivity. To decrease the negative effect of salinity and improve growth performance, some strategies have been used, such as exogenous application of plant growth regulators (i.e. gibberellic acid, GA 3 ), or arbuscular mycorrhizal fungi (AMF) inoculation. To gain insights about the cross-talk effect of exogenous GA 3 application and AMF inoculation on growth under salinity conditions, tomato plants (Solanum lycopersicum, cv. TT-115) were inoculated or not with the AMF Rhizophagus irregularis and exposed to different treatments during two weeks: 0M GA 3 +0mM NaCl, 10 -6 M GA 3 +0mM NaCl, 0M GA 3 +100mM NaCl and 10 -6 M GA 3 +100mM NaCl. Results have revealed that AMF inoculation or GA 3 application alone, but especially their interaction, resulted in growth improvement under salinity conditions. The growth improvement observed in AMF-inoculated tomato plants under salinity conditions was mainly associated to ionic factors (higherK concentration and K/Na ratio) while the alleviating effect of GA 3 application and its interaction with AMF appear to be due to changes in the hormonal balance. Foliar GA 3 application was found to increase the active gibberellins (GAs), resulting in a positive correlation between GA 3 and the growth-related parameters. Furthermore, cytokinins, indoleacetic acid and abscisic acid concentrations increased in AMF inoculated or GA 3 treated plants but, notably, in AMF plants treated with GA 3 , which showed improved growth under salinity conditions. This suggests that there is an interactive positive effect between GAs and AMF which alleviates growth impairment under salinity conditions by modifying the hormonal balance of the plant. Copyright © 2017 Elsevier GmbH. All rights reserved.