Effect of protein fouling on filtrate flux and virus breakthrough behaviors during virus filtration process.

Virus filtration process is used to ensure viral safety in the biopharmaceutical downstream processes with high virus removal capacity (i.e., >4 log10 ). However, it is still constrained by protein fouling, which results in reduced filtration capacity and possible virus breakthrough. This study investigated the effects of protein fouling on filtrate flux and virus breakthrough using commercial membranes that had different symmetricity, nominal pore size, and pore size gradients. Flux decay tendency due to protein fouling was influenced by hydrodynamic drag force and protein concentration. As the results of prediction with the classical fouling model, standard blocking was suitable for most virus filters. Undesired virus breakthrough was observed in the membranes having relatively a large pore diameter of the retentive region. The study found that elevated levels of protein solution reduced virus removal performance. However, the impact of prefouled membranes was minimal. These findings shed light on the factors that influence protein fouling during the virus filtration process of biopharmaceutical production.

Disintegration of Waste Activated Sludge by Thermally-Activated Persulfates for Enhanced Dewaterability.

Oxidation by persulfates at elevated temperatures (thermally activated persulfates) disintegrates bacterial cells and extracellular polymeric substances (EPS) composing waste-activated sludge (WAS), facilitating the subsequent sludge dewatering. The WAS disintegration process by thermally activated persulfates exhibited different behaviors depending on the types of persulfates employed, that is, peroxymonosulfate (PMS) versus peroxydisulfate (PDS). The decomposition of PMS in WAS proceeded via a two-phase reaction, an instantaneous decomposition by the direct reaction with the WAS components followed by a gradual thermal decay. During the PMS treatment, the WAS filterability (measured by capillary suction time) increased in the initial stage but rapidly stagnated and even decreased as the reaction proceeded. In contrast, the decomposition of PDS exhibited pseudo first-order decay during the entire reaction, resulting in the greater and steadier increase in the WAS filterability compared to the case of PMS. The treatment by PMS produced a high portion of true colloidal solids (<1 µm) and eluted soluble and bound EPS, which is detrimental to the WAS filterability. However, the observations regarding the dissolved organic carbon, ammonium ions, and volatile suspended solids collectively indicated that the treatment by PMS more effectively disintegrated WAS compared to PDS, leading to higher weight (or volume) reduction by postcentrifugation.

Synthesis and characterization of ethosomal contrast agents containing iodine for computed tomography (CT) imaging applications.

As a first step in the development of novel liver-specific contrast agents using ethosomes for computed tomography (CT) imaging applications, we entrapped iodine within ethosomes, which are phospholipid vesicular carriers containing relatively high alcohol concentrations, synthesized using several types of alcohol, such as methanol, ethanol, and propanol. The iodine containing ethosomes that were prepared using methanol showed the smallest vesicle size (392 nm) and the highest CT density (1107 HU). The incorporation of cholesterol into the ethosomal contrast agents improved the stability of the ethosomes but made the vesicle size large. The ethosomal contrast agents were taken up well by macrophage cells and showed no cellular toxicity. The results demonstrated that ethosomes containing iodine, as prepared in this study, have potential as contrast agents for applications in CT imaging.

Three methods to measure the photopolymerization kinetics for different radiant emittance and composite type.

Photopolymerization kinetics affects the curing time, degree of conversion, polymerization shrinkage, and mechanical properties of composites. The aim of this study was to compare three methods (temperature, heat flow, and polymerization shrinkage) for photopolymerization kinetics measurement of composites. The photopolymerization kinetics of four composites (2 packable and 2 flowable) were measured with an LED light for 20 s (radiant emittance: 2,100 mW/cm2). For the two packable composites, photopolymerization kinetics was measured with varying the radiant emittance and exposure time. For each measurement method, peak times were determined as the time when maximum temperature rise, heat flow, and shrinkage rate occurred, respectively. The photopolymerization kinetics differed among the measurement methods. The photopolymerization kinetics of composites changed as the radiant emittance and composite type varied. In clinical practice and research on the composite restoration, the kinetics should be considered comprehensively with the complementary use of various measurement methods.

Long-term Outcomes of Polytetrafluoroethylene Bicuspid Pulmonary Valve Replacement.

BACKGROUND: In 2016 we reported promising midterm outcomes of bicuspid pulmonary valve replacement using 0.1-mm polytetrafluoroethylene (PTFE) membrane. This follow-up study analyzes long-term outcomes and risk factors for reintervention and structural valve deterioration (SVD). METHODS: We performed a retrospective review of the original 119 patients who underwent PTFE bicuspid pulmonary valve replacement. Median patient age was 16.9 years (range, 0.4-57.1). Reintervention was defined as any surgical or percutaneous catheter procedure on the PTFE valve. SVD was defined as development of a peak pressure gradient ≥ 50 mm Hg or at least a moderate amount of pulmonary regurgitation on follow-up echocardiography. RESULTS: The median follow-up duration was 9.5 years. The survival rate was 96.5% at 5 and 10 years, with 2 early and 2 late mortalities. Freedom from reintervention was 90.0% at 5 years and 63.3% at 10 years. Freedom from SVD was 92.8% at 5 years and 51.1% at 10 years, with regurgitation the predominant mode (64.6%). Freedom from both reintervention and SVD at 5 and 10 years were 89.1% and 49.5%, respectively. Multivariable analysis identified smaller valve diameter (hazard ratio, 0.82; P < .001) and more than trivial pulmonary regurgitation at discharge (hazard ratio, 5.81; P < .001) as risk factors for reintervention or SVD. CONCLUSIONS: Long-term results of the PTFE bicuspid pulmonary valve replacement were acceptable. However, improvements may be needed to reduce technical error and improve durability. Smaller valve diameter and more than trivial pulmonary regurgitation at discharge were risk factors for reintervention or SVD, warranting careful follow-up for timely reintervention.

Whitening Efficacy of Toothpastes on Coffee-Stained Teeth: An Enamel Surface Analysis.

AIM: This study aimed to identify the optimal toothpaste for removing coffee-induced stains while also evaluating its impact on tooth enamel through roughness and abraded depth parameters, providing a comprehensive understanding of their effects. MATERIALS AND METHODS: Three whitening toothpastes and 2 conventional toothpastes were prepared for a simulated brushing procedure on coffee-stained bovine enamel tooth specimens. Using a toothbrushing machine, up to 10,000 brushstrokes were completed, while spectrophotometric readings were taken at designated intervals. A mixed-effects model for statistical analysis determined the effects of toothpaste and brushing on colour change, roughness, and abraded depth. RESULTS: Whitening toothpastes significantly deviated from the control (P < .001, P < .001, and P < .003, respectively), whereas the conventional toothpaste did not exhibit a significant contrast (P < .081). Regarding colour restoration following coffee staining, whitening toothpastes showed higher restoration than conventional toothpastes. Surface roughness and abraded depth parameters increased with accumulated brushing. CONCLUSIONS: Sodium hexametaphosphate-containing toothpaste demonstrated the highest efficacy in removing coffee-induced stains and restoring tooth colour. Nevertheless, this stronger whitening effect was associated with increased abrasion. While conventional toothpastes exhibited some whitening effects, the most substantial improvement in lightness was consistently observed with whitening toothpastes. CLINICAL RELEVANCE: Understanding how whitening toothpaste affects enamel integrity is crucial for refining formulations and advancing dental care. This knowledge lays the groundwork for more effective oral care products and improved whitening procedures, ultimately enhancing the overall quality of dental treatments.

Effect of translucency and absorbance of composite on temperature change during photopolymerization.

This study investigated the effect of translucency and absorbance of conventional (FiltekTM-Z350-XT) and bulk-fill (Tetric®-N-Ceram) composites on temperature change during photopolymerization, using a non-contact infrared sensor. Three shades from each composite were selected to prepare disk-shaped specimens (n=3), which then photopolymerized with LED-light for 20 s. A second light exposure was performed on the photopolymerized specimens. The first peak temperature rise during composite photopolymerization (ΔTtotal), second peak temperature rise by the light (ΔTlight), and net peak temperature rise by composite curing heat (ΔTcomposite) were obtained from the temperature change vs. time curve. The changes in ΔTtotal and ΔTlight with varying the composite shade were greater than those in ΔTcomposite. The conventional composite showed higher ΔTtotal and ΔTlight than bulk-fill composite. ΔTtotal and ΔTlight increased as translucency parameter decreased, and absorbance increased. The potential risk for heat-induced pulpal damage should be considered when selecting a composite shade, especially for deep cavities.

Transformation of microplastics by oxidative water and wastewater treatment processes: A critical review.

Microplastics (MPs) are contaminants of emerging concern that accumulate in various environments, where they pose threats to both the ecosystem and public health. Since MPs have been detected in drinking water resources and wastewater effluents, more efficient treatment is needed at wastewater treatment plants (WWTPs) and drinking water treatment plants (DWTPs). This review discusses the potential of biological, photochemical, Fenton (-like) systems, ozonation, and other oxidation processes in the treatment of MPs in terms of their indicators of oxidation such as mass loss and surface oxidation. The oxidation processes were further analyzed in terms of limitations and environmental implications. Most previous studies examining MPs degradation using conventional treatments-such as UV disinfection, ozonation, and chlorination-employed significantly higher doses than the common doses applied in DWTPs and WWTPs. Owing to such dose gaps, the oxidative transformation of MPs observed in many previous studies are not likely to occur under practical conditions. Some novel oxidation processes showed promising MPs treatment efficiencies, while many of them have not yet been applied on a larger scale due to high costs and the lack of extensive basic research. Health and environmental impacts related to the discharge of oxidized MPs in effluents should be considered carefully in different aspects: the role as vectors of external pollutants, release of organic compounds (including organic byproducts from oxidation) and fragmentation into smaller particles as MPs circulate in the ecosystem as well as the possibility of bioaccumulation. Future research should also focus on ways to incorporate developed oxidation processes in DWTPs and WWTPs to mitigate MPs contamination.

Real-time morphological detection of label-free submicron-sized plastics using flow-channeled differential interference contrast microscopy.

Owing to the surge in plastic waste generated during the COVID-19 pandemic, concerns regarding microplastic pollution in aqueous environments are increasing. Since microplastics (MPs) are broken down into submicron (< 1 µm) and nanoscale plastics, their real-time morphological detection in water is necessary. However, the decrease in the scattering cross-section of MPs in aqueous media precludes morphological detection by bright-field microscopy. To address this problem, we propose and demonstrate a differential interference contrast (DIC) system that incorporates a magnification-enhancing system to detect MPs in aqueous samples. To detect MPs in both the stationary and mobile phases, a microfluidic chip was designed, taking into consideration the imaging depth of focus and flow resistance. MPs of various sizes flowing in deionized, tap, and pond water at varying speeds were observed under Static and Flow conditions. Successful real-time morphological detection and quantification of polystyrene beads down to 200 nm at a constant flow rate in water were achieved. Thus, the proposed novel method can significantly reduce analysis time and improve the size-detection limit. The proposed DIC microscopy system can be coupled with Raman or infrared spectroscopy in future studies for chemical composition analysis. ENVIRONMENTAL IMPLICATION: Microplastics (MPs), particularly submicron plastics < 1-µm, can pose a risk to human health and aquatic ecosystems. Existing methods for detecting MPs in the aqueous phase have several limitations, including the use of expensive instruments and prolonged and labor-intensive procedures. Our results clearly demonstrated that a new low-cost flow-channeled differential interference contrast microscopy enables the real-time morphological detection and quantification of MPs down to 200 nm under flowing conditions without sample labeling. Consequently, our proposed rapid method for accurate quantitative measurements can serve as a valuable reference for detecting submicron plastics in water samples.

Real-time measurement of transmittance changes during photo-polymerization of conventional and bulk-fill composites.

This study investigated transmittance changes during photo-polymerization of composites in real-time. The transmittance changes of one conventional micro-hybrid, three conventional nano-hybrid, and four bulk-fill composites were measured before, during, and after photo-polymerization, and the maximum rate of transmittance change was compared with that of polymerization shrinkage. A significant difference in transmittance of composite between before and after photo-polymerization was observed. The transmittance of composites except for one bulk-fill composite increased during photo-polymerization. There was a correlation between the maximum rate of transmittance change and the maximum rate of polymerization shrinkage. The transmittance analysis of composites gives very important information to know for the final aesthetic restoration and allows to evaluate polymerization kinetics.

Effects of wall compliance and light-curing protocol on wall deflection of simulated cavities in bulk-fill composite restoration.

BACKGROUND/PURPOSE: Cuspal deflections in composite restoration have been investigated with considering wall compliance of human tooth cavity and light-curing protocol. The purpose of this study was to investigate effects of mold wall compliance and radiant emittance of LED light on the wall deflection of simulated aluminum mold cavities restored with a bulk-fill composite. MATERIALS AND METHODS: Sixty aluminum molds simulating a class II mesio-occluso-distal (MOD) cavity (6 W × 8 L × 4 D mm; W, width; L, length; D, Depth) were prepared and allocated to three groups with varying mold wall thicknesses of 1, 2, and 3 mm. The molds were bulk-filled with a bulk-fill composite and photo-cured. Four light-curing protocols were used: three duty ratios/exposure times: 100%/20 s, 50%/40 s, or an increasing mode (0 → 100%)/40 s with a pulse width modulated (PWM) LED curing light and one 20 s exposure time with a commercial LED light. RESULTS: Mean mold wall deflection at 2000 s decreased with increasing mold wall thickness (1, 2, and 3 mm) (p < 0.05). Wall deflections with 1- and 2-mm-thick molds exhibited no statistically significant differences among light-curing protocols (p > 0.05). However, in the 3-mm-thick mold, wall deflections with low radiant emittance were significantly lower than those with high radiant emittance (p < 0.05). CONCLUSION: In composite restoration of class II MOD cavities, lowering the radiant emittance of LED light can reduce the mold wall deflection only in low compliance cavities.

Effect of radiant emittance of an LED curing light on the cuspal deflection of a simulated tooth cavity in bulk-fill composite restoration: A novel simulation method.

In this study, a novel method for simulating human teeth was developed, with which the effect of radiant emittance of an LED curing light on the cuspal deflection was investigated. A mesio-occluso-distal (MOD) cavity was replicated using a heat-pressed ceramic and lost wax technique, and the cuspal compliance and cuspal deflection of the replicated ceramic teeth and extracted human teeth were evaluated. The replicated ceramic teeth were restored using a nano bulk-fill composite and photopolymerized using three different protocols. Data were analyzed with t-test and one-way ANOVA (α=0.05). The cuspal compliance and cuspal deflection of the replicated ceramic teeth and extracted human teeth were similar. Cuspal deflections did not differ significantly among the tested photopolymerization protocols. Thus, the replicated ceramic teeth were an effective simulation of human teeth. During bulk-fill composite restoration of the MOD cavity, cuspal deflection was not affected by changing the radiant emittance of the LED light.

Effects of cuspal compliance and radiant emittance of LED light on the cuspal deflection of replicated tooth cavity.

The aim was to investigate effects of compliance and radiant emittance on cuspal deflection. A mesio-occluso-distal cavity was replicated using a flowable composite and steel rods with different diameters. To investigate the effect of cuspal compliance on deflection, the replicated tooth and extracted human tooth cavities were bulk-filled with a micro-hybrid composite. The replicated cavities with 2.0-mm-diameter steel rods were restored with bulk-filling of the micro-hybrid or a nano bulk-fill composite and photo-cured with four protocols. The cuspal deflection was the highest in the replicated tooth without steel rod, followed by with 1.0-, 1.5-, and 2.0-mm steel rods, and significantly lower in the human tooth. Cuspal deflections showed no significant differences among light-curing protocols, and that in the micro-hybrid composite were higher than the nano bulk-fill composite. To reduce cuspal deflection of a high compliance cavity, selecting the proper composite based on physical properties is more important than light-curing protocol.

Shockwave application enhances the effect of dentin desensitizer.

OBJECTIVES: The purpose of this study was to develop a new device that can improve the effect of desensitizer using shockwaves and to verify its efficacy. METHODS: A micro-shockwave generator was developed using a piezoelectric actuator (PIA-1000, piezosystem jena GmbH, Jena, Germany), an Arduino Uno microcontroller (Arduino, Torino, Italy), and a high voltage pulser (HVP-1000, piezosystem jena GmbH) at 700 V (400 A) and 100 µs. The occlusal surfaces of 20 extracted human upper and lower third molars without caries or restoration were reduced to expose the occlusal dentin, and the prepared occlusal surfaces were acid-etched with 32% phosphoric acid to remove the smear layer. The tooth specimens were connected to a fluid flow measurement instrument (nanoFlow, IB SYSTEMS, Seoul, Korea), permeability through dentin via dentinal fluid flow (DFF) was measured for 300 s, and the average DFF rate (Baseline DFF rate) was calculated. A desensitizer (SuperSeal, Phoenix Dental, Fenton, MI, USA) was applied to the acid-etched occlusal dentin surface of 10 randomly selected tooth specimens, left for 10 s, and rubbed with a microbrush for 30 s (Group 1). For the remaining teeth, the desensitizer was applied, and a shockwave (100 µm stroke, 10,000 G) was applied for 10 s (2 shots/s) and rubbed with a microbrush for 30 s (Group 2). After desensitizer application, subsequent DFF was measured for 600 s, and the average DFF rate was calculated (post-application DFF rate). DFF was continuously measured in real-time at 25 ±â€¯0.5 ℃ under a hydrostatic pressure of 25 cm. The percentage reduction in DFF rate after desensitizer application (with or without shockwave) was calculated with respect to baseline DFF rate. Data were analyzed with independent t-test (α = 0.05). RESULTS: For all tooth specimens, DFF rate decreased after desensitizer application irrespective of the presence of shockwaves. The percentage reduction in DFF rate of SuperSeal with shockwave (Group 2) was 42.8 ±â€¯19.0%, which was significantly higher than the 26.2 ±â€¯13.6% of the SuperSeal only group (Group 1) (p < 0.05). SIGNIFICANCE: Measurement of DFF change in real-time shows that shockwaves can help reduce dentin permeability beyond that SuperSeal dentin desensitizer produced alone.

Effect of Etching Procedures on the Adhesion of Biofilm-Coated Dentin.

Oral biofilms coat all surfaces in the oral cavity including the exposed dentin surface. This study aimed to investigate biofilm removal by acid etching procedures and the effects of the residual biofilm on dentin surfaces on composite-dentin adhesion. Dentin discs were assigned to five groups: no biofilm formation (C); biofilm formation and no surface treatment (BF); biofilm formation and acid etching (BF-E); biofilm formation and acid etching followed by chlorhexidine soaking (BF-EC); and biofilm formation and rubbing with pumice, followed by acid etching (BF-RE). Biofilms were formed on saliva-precoated dentin discs by soaking the discs in Streptococcus mutans (S. mutans) suspension. Biofilm removal from the dentin surface was evaluated quantitatively and qualitatively by confocal laser scanning microscopy and scanning electron microscopy, respectively. To compare the bond strength of the biofilm-coated dentin discs with the surface treatments, specimens were assigned to four groups: no biofilm formation and acid etching (C-E); BF-E; BF-EC; and BF-RE. Assessments of the micro-shear bond strength and subsequent failure modes were performed. BF-E and BF-EC did not remove the biofilm, whereas BF-RE partially removed the biofilm attached to the dentin (p < 0.05). The bond strength of BF-RE was significantly higher than those of BF-E and BF-EC, but lower than that of C-E (p < 0.05). In conclusion, mechanical biofilm removal is recommended before etching procedures to enhance adhesion to the biofilm-coated dentin.

Oil droplet generation in PDMS microchannel using an amphiphilic continuous phase.

This paper reports an amphiphilic solution can be used as a new continuous phase to generate double droplet emulsions (water/oil/IPA) with neither surface treatment nor surfactant in PDMS microfluidic chip. The affinity of various amphiphilic solutions in the microchannel was influenced by the polarity ratio and the size of molecules. The polarity ratio of isopropyl alcohol (IPA) was closest to that of the recovered PDMS surface and the chain length of IPA was also suitable for high affinity. IPA showed the highest affinity for the recovered PDMS and was selected as the continuous phase to form oil droplets in a PDMS microchannel. With this new continuous phase solution, IPA, we could successfully generate not only oil droplets but also double emulsions in the PDMS microfluidic chips.

Effect of pulse-width-modulated LED light on the temperature change of composite in tooth cavities.

OBJECTIVE: The purpose of this study was to investigate the effects of the radiant emittance and cure time of pulse width modulation (PWM)-controlled LED light on the temperature change of composite and dentin. METHODS: Class I cavities (M-D 6mm, B-L 4mm, Depth 2.5mm) were prepared on 30 extracted human molars and vertically sectioned to expose the mesial side of the cavity and tooth. Cavities were filled with Bulk Fill Posterior Restorative (BFP, 3M ESPE) and cured with an LED light. The duty ratio (% of time the light is on) and cure time of the LED light were controlled using an Arduino UNO microcontroller (PWM) as follows (6 groups, n=5): 10%/100 s, 30%/33.3s, 50%/20s, 100%/10s, Increase mode (0→100%)/20s, and Decrease mode (100→0%)/20s. All measurements were performed at 100Hz PWM with the constant total radiant exposure. Thermograms of the specimens were recorded using an infrared thermal camera (VarioCamhr head 700, InfraTec GmbH) for a pre-cure time of 20s, cure time, and a post-cure time of 100s at room temperature of 30±0.5°C. Temperature change data on the composite and dentin surfaces were collected at incremental distances of 0.625mm and 1mm from the top of the cavity to the pulp. Data were statistically analyzed using two-way ANOVA and Tukey's post-hoc test at α=0.05. RESULTS: A rapid temperature increase occurred within the cavity during light curing. The maximum temperature rises (ΔTmax) were observed at 0.625mm apical from the top and middle of the cavity. The ΔTmax ranged from 7.62 to 16.74°C at 0.625mm apical from the top, 4.83 to 11.39°C at the floor of the cavity, and 3.16 to 8.09°C in the dentin 1mm beneath the cavity base. The ΔTmax of composite and dentin increased and the time to reach ΔT=5°C decreased with increasing duty ratio at constant radiant exposure. In the Increase mode, ΔTmax was lower than that of 50%/20s mode. The ΔTmax in the Decrease mode was similar to that of 100%/10s mode. SIGNIFICANCE: The PWM-LED curing light system controlled by a microcontroller provided a useful tool of varying the radiant emittance and cure time with constant radiant exposure to evaluate temperature change of composite and dentin. These result will be helpful to determine proper curing modes with varying radiant emittance of the LED curing light for decreasing temperature change of composite and dentin. At constant radiant exposure and cure times, the Increase mode showed lower and slower temperature rises than the 50%/20s and Decrease mode. Within the limitations of this in vitro study, when radiant exposure is constant, a curing light with lower radiant emittance can induce relatively low thermal transfer, thereby decreasing the risk of pulpal damage.

Absorption of a volatile organic compound by a jet loop reactor with circulation of a surfactant solution: performance evaluation.

Biofiltration shows high efficiency for the removal of industrial waste gases and reliable operational stability at low investment and operating cost, especially when the VOC concentration is low, such as 100 ppmv (micro LL(-1)) or less. However, it has been reported that the abrupt change in VOC concentrations leads to the failure of the biofilter. Hence, the pretreatment of waste gases is necessary to ensure the stable operation of the biofilter. The objective of this study is to develop a jet loop reactor (JLR) with circulation of a surfactant solution to lower the concentration of VOCs, especially hydrophobic VOCs. Toluene and Tween 81 were used as a model industrial waste gas and a surfactant, respectively. Among several non-ionic surfactants tested, Tween 81 showed the most rapid dissolution of toluene. When a JLR is replaced with fresh Tween 81 solution (0.3% w/v) every hour, it successfully absorbed for 48 h over 90% of the toluene in an inlet gas containing toluene at 1000 ppmv (microL L(-1)) or less. Therefore, JLR with circulation of a surfactant solution is believed to ensure the stable operation of the biofilter even with the unexpected increase in the VOC concentrations.

Effect of pulse width modulation-controlled LED light on the polymerization of dental composites.

OBJECTIVES: The purpose of this study was to investigate the effects of radiant emittance and cure time of pulse width modulation (PWM)-controlled LED light on polymerization shrinkage/stress kinetics and surface hardness of dental composites. METHODS: A conventional (Filtek Z250) and a bulk-fill (Filtek Bulk Fill Posterior; BFP) composite were investigated. The duty ratio (% of time the light is on) and cure time of the LED light were controlled using an Arduino UNO microcontroller (PWM) as follows: 10%/100s, 20%/50s, 30%/33.3s, 40%/25s, 50%/20s, 100%/10s, Increase mode (0→100%)/20s, and Decrease mode (100→0%)/20s at 50Hz. The radiant exposure of each group was constant. Polymerization shrinkage/stress and Vickers hardness (HV) of composites were measured for each curing condition (n=5). Peak shrinkage/stress rate (Rsh/Rst) and time at peak shrinkage/stress rate (Tsh/Tst) were also determined. RESULTS: There was no significant difference in polymerization shrinkage or HV of composites with varying duty ratio. However, polymerization shrinkage stress, Rsh, and Rst increased and Tsh and Tst decreased with increasing duty ratio. The polymerization shrinkage stress and Rst of the Increase mode group were similar to those of the 50% duty ratio group, and the Tst of the Increase mode was delayed. The polymerization shrinkage/stress kinetics of the Decrease mode group were comparable to those of the 100% duty ratio group. Under the same light curing conditions, polymerization shrinkage/stress, Rsh, Rst, and HV of Z250 were higher than those of BFP, and the Tsh and Tst of Z250 were shorter than those of BFP. SIGNIFICANCE: With constant radiant exposure, evaluation of polymerization shrinkage/stress kinetics and their relationships could be performed by a PWM-controlled LED curing light. These results will be helpful to determine proper curing modes with varying radiant emittance of the LED curing light for decreasing polymerization shrinkage stress of dental composites. Within the limitations of this in vitro study, when radiant exposure is constant, polymerization shrinkage stress with low initial radiant emittance can be reduced compared to that with high initial radiant emittance.

Outcomes after extracardiac Fontan procedure with a 16-mm polytetrafluoroethylene conduit.

OBJECTIVES: We evaluated the outcomes of patients who underwent extracardiac Fontan circulation procedures (ECFP) and received 16-mm polytetrafluoroethylene conduits. METHODS: From June 1997 to May 2015, among the 408 patients who underwent ECFP, 66 patients (Group S) also received 16-mm polytetrafluoroethylene conduits. To compare this patient cohort with similarly sized patients who received larger conduits, a matched cohort (66 patients, Group L) was selected according to age and body weight. RESULTS: The mean age, body weight and Nakata index at ECFP in Groups S and L were 2.9 ± 1.2 and 3.1 ± 1.2 years (P = 0.243), 13.0 ± 2.4 and 13.0 ± 2.3 kg (P = 0.101), 175.3 ± 59.0 and 236.1 ± 75.1 mm2/m2 (P = 0.005), respectively. The mean follow-up periods for Groups S and L were 7.8 ± 6.0 and 9.1 ± 4.9 years (P = 0.150), respectively. The conduit size of Group L was 19.2 ± 1.4 mm (P < 0.001). There was no significant difference in mortality between the groups (P = 0.109). The freedom from reoperation was 94.0 ± 3.4% in Group S and 79.3 ± 5.7% in Group L after 10 years (P = 0.070). Late-occurring morbidities included protein-losing enteropathy (2 in Group S, 4 in Group L; P = 0.491) and thromboembolism (0 in Group S, 4 in Group L; P = 0.206). There was a significant difference in conduit-related events between the groups (1 in Group S, 5 in Group L; P = 0.031). In a paired cohort from the 2 groups including patients who were followed-up for more than 10 years (15 patients from each group), the body mass index was 51.0 ± 33.2% in Group S and 30.3 ± 34.2% in Group L. The decreases in the conduit cross-sectional areas for the paired patients in Group S (n = 20) and Group L (n = 20) were 14.9 ± 19.7% and 24.5 ± 15.5% (P = 0.076), respectively. Coarse liver parenchyma was detected in 9 of 23 (39.1%) patients from Group S and in 7 of 18 (38.8%) patients from Group L upon ultrasonography. CONCLUSIONS: The 16-mm polytetrafluoroethylene conduit for ECFP showed acceptable outcomes and good haemodynamic status in small-sized patients. According to our results, small patients do not require large conduits to accommodate their growth potential.