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Journal of Clinical Medicine Mar 2023The aim of this in vitro study was to evaluate the remineralizing ability of three glass ionomers on demineralized dentin with different thicknesses and time periods....
The aim of this in vitro study was to evaluate the remineralizing ability of three glass ionomers on demineralized dentin with different thicknesses and time periods. Fifty third molars were obtained and were sectioned into 1-, 2-, and 3-mm thick slices (n = 36 for each thickness). The specimens were demineralized with 18% EDTA for 2 h. From the glass ionomer cements (GICs) under study (Ketac Molar Aplicap, Equia Forte, or Riva Light Cure), 1 mm was placed over each slice, set, and preserved in PBS until observation after 1, 7, 14, and 28 days after placement. For each material, thickness, and time, three samples were prepared. Using Fourier Transform Infrared Spectrometry (FTIR), apatite formation was determined on the side opposite to that on which the material had been placed. By means of Energy Dispersive Spectroscopy (EDX), the changes in the Calcium/Phosphate (Ca/P) ratio were evaluated. These changes were compared between the different materials by means of a two-way ANOVA test, considering time and dentin thickness, for a significance level of < 0.05. Results: FTIR showed a peak at 1420 cm, evidencing the presence of carbonated hydroxyapatite in all the materials after 14 days, which indicates that a remineralization process occurred. Riva Light Cure showed the most homogeneous results at all depths at 28 days. The Ca/P ratio was maximum at 7 days in 2 mm of dentin for Riva Light Cure and Equia Forte HT (3.16 and 3.07; respectively) and for Ketac Molar at 14 days in 1 mm (3.67). All materials induced remineralization. Equia Forte achieved the greatest effect at 2 mm and Ketac Molar at 1 mm, whereas Riva Light Cure showed similar results at all depths. In terms of Ca/P ratio, Equia Forte and Riva Light Cure remineralized best at 2 mm, whereas for Ketac Molar, it was 1 mm. Carbonate apatite formation was higher at 24 h and 7 days for Ketac Molar, whereas it decreased at 14 days for Ketac Molar and peaked in Riva Light Cure and Equia Forte.
PubMed: 36983434
DOI: 10.3390/jcm12062434 -
Scientific Reports Dec 2023Thin-film antimony chalcogenide binary compounds are potential candidates for efficient and low-cost photovoltaic absorbers. This study investigates the performance of...
Thin-film antimony chalcogenide binary compounds are potential candidates for efficient and low-cost photovoltaic absorbers. This study investigates the performance of SbS and SbSe as photovoltaic absorbers, aiming to optimize their efficiency. The standalone SbS and SbSe sub-cells are analyzed using SCAPS-1D simulations, and then a tandem structure with SbS as the top-cell absorber and SbSe as the bottom-cell absorber is designed, using the filtered spectrum and the current matching technique. The optimal configuration for maximum efficiency is achieved by adjusting the thickness of the absorber layer. The results show that antimony chalcogenide binary compounds have great potential as photovoltaic absorbers, enabling the development of efficient and low-cost solar cells. A remarkable conversion efficiency of 22.2% is achieved for the optimized tandem cell structure, with absorber thicknesses of 420 nm and 1020 nm for the top and bottom sub-cells respectively. This study presents a promising approach towards high-performance tandem solar cells.
PubMed: 38114523
DOI: 10.1038/s41598-023-49269-w -
Polymers Jul 2023This paper aimed to experimentally clarify the dynamic crushing mechanism and performance of ethylene vinyl acetate copolymer (EVA) and analyze the influence of density...
This paper aimed to experimentally clarify the dynamic crushing mechanism and performance of ethylene vinyl acetate copolymer (EVA) and analyze the influence of density and thickness on its mechanical behavior and energy absorption properties under dynamic impact loadings. Hence, a series of dynamic compression tests were carried out on EVA foams with different densities and thicknesses. When the impact energy is 66.64 J, for foam with a density of 150 kg/m, the maximum contact force, maximum displacement, maximum strain, absorbed energy, and specific energy absorption () increased by 20 ± 2%, -38.5 ± 2%, -38.5 ± 2%, 4 ± 2%, and 105 ± 2%, respectively, compared to foam with a density of 70 kg/m. The ratios of absorbed energy to impact energy for different thickness specimens are almost equal. The specimen density has no effect on the efficiency of energy absorption and has a greater effect on the . Meanwhile, when the impact energy-to-thickness ratio is 1680 J/m, compared to foam with a thickness of 30 mm, the maximum contact force, maximum displacement, maximum strain, absorbed energy, and for foam with a thickness of 60 mm increased by 28.5 ± 2%, 211.3 ± 2%, 56.6 ± 2%, 100.8 ± 2%, and 0.4 ± 0.5%, respectively. When the impact energy is 66.64 J, compared to foam with a thickness of 30 mm, the maximum contact force, maximum displacement, maximum stain, absorbed energy, and for foam with a thickness of 60 mm increased by -42.5 ± 2%, 163.5 ± 2%, 31.7 ± 2%, 4.1 ± 2%, and 4.1 ± 2%, respectively. The of two different-thickness EVA specimens is almost equal, about 2.8 J/g. The ratios of absorbed energy to impact energy for different thickness specimens are almost equal, both at 72%. The specimen thickness has no effect on the efficiency of energy absorption and has a greater effect on the maximum contact force. In the range of impact energy, thickness, and density studied, the absorbed energy and are not affected by the thickness of EVA specimens and are determined by the impact energy. The density has no significant effect on the absorbed energy but has a greater effect on the . However, for EVA foams, the greater the density, the greater the mass, and the higher the cost. Taking into account lightweight and cost factors, when optimizing cushioning design within a safe range, we can choose EVA foams with a smaller density and thickness.
PubMed: 37514406
DOI: 10.3390/polym15143016 -
ACS Omega Aug 2021Long-life and self-powered betavoltaic batteries are extremely attractive for many fields that require a long-term power supply, such as space exploration, polar...
Long-life and self-powered betavoltaic batteries are extremely attractive for many fields that require a long-term power supply, such as space exploration, polar exploration, and implantable medical technology. Organic lead halide perovskites are great potential candidate materials for betavoltaic batteries due to the large attenuation coefficient and the long carrier diffusion length, which guarantee the scale match between the penetration depth of β particles and the carrier diffusion length. However, the performance of perovskite betavoltaics is limited by the fabrication process of the thick and high-crystallinity perovskite film. In this work, we demonstrated high-performance perovskite betavoltaic cells using thick, high-quality, and wide-band-gap MAPbBr polycrystalline films. The solvent annealing method was adopted to improve the crystallinity and eliminate the pinholes in the MAPbBr film. The optimal MAPbBr betavoltaic cell achieved a power conversion efficiency (PCE) of 5.35% and a maximum output power of 1.203 μW under radiation of electrons of 15 keV with an equivalent activity of 253 mCi. These results are a nearly 50% improvement from previous reports. Effects of the MAPbBr perovskite layer thickness on the device performance were also discussed. The mechanisms of film-growth processes and device physics could provide insights for the research community of perovskites and betavoltaics.
PubMed: 34368587
DOI: 10.1021/acsomega.1c03053 -
Indian Journal of Ophthalmology Nov 2019To evaluate diagnostic ability of macular ganglion cell layer-inner plexiform layer (GCL-IPL) for detection of preperimetric glaucoma (PPG) and perimetric glaucoma and...
PURPOSE
To evaluate diagnostic ability of macular ganglion cell layer-inner plexiform layer (GCL-IPL) for detection of preperimetric glaucoma (PPG) and perimetric glaucoma and comparison with peripapillary RNFL.
METHODS
Three hundred and thirty seven eyes of 190 patients were enrolled (127 normals, 70 PPG, 140 perimetric glaucoma). Each patient underwent detailed ocular evaluation, standard automated perimetry, and spectral domain optical coherence tomography. Diagnostic abilities of GCL-IPL and RNFL parameters were determined. Data were compared using one-way analysis of variance, Pearson's Chi-square test, and area under the curve (AUC).
RESULTS
After adjusting for age, gender, and signal strength, all GCL-IPL and RNFL parameters except mean thickness and disc area differed significantly. Among GCL-IPL thicknesses, inferotemporal had the highest AUC (0.865) for classifying perimetric glaucoma from normals, inferior (0.746) for PPG from normals, and inferotemporal (0.750) for perimetric glaucoma from PPG. When using RNFL, inferior thickness had the highest AUC (0.922) in discriminating POAG from normal, while the same parameter had lower AUC (0.813) in discriminating PPG from normal. The average thickness had maximum AUC (0.775) for discriminating POAG from PPG. For discriminating perimetric glaucoma and normals, inferotemporal GCL-IPL had the highest strength (sensitivity 81.43% and specificity 77.96%), slightly lower than inferior RNFL thickness (sensitivity 87.85% and specificity 84.26%). The same parameters were sensitive in discriminating perimetric glaucoma from PPG (87.14% and 92.85%, respectively). However, their specificities were poor (56.43% both).
CONCLUSION
RNFL had better diagnostic ability, when compared with GCL-IPL for detecting PPG and perimetric glaucoma. However, difference was small and may not be clinically relevant.
Topics: Cross-Sectional Studies; Female; Glaucoma; Humans; Intraocular Pressure; Macula Lutea; Male; Middle Aged; Nerve Fibers; ROC Curve; Retinal Ganglion Cells; Retrospective Studies; Tomography, Optical Coherence; Visual Field Tests; Visual Fields
PubMed: 31638046
DOI: 10.4103/ijo.IJO_1955_18 -
The British Journal of Radiology Oct 2022To develop an automated method for 3D magnetic resonance (MR) vessel wall image analysis to facilitate morphologic quantification of intra- and extracranial arteries,...
OBJECTIVE
To develop an automated method for 3D magnetic resonance (MR) vessel wall image analysis to facilitate morphologic quantification of intra- and extracranial arteries, including vessel centerline tracking, vessel straightening and reformation, vessel wall segmentation based on convoluted neural networks (CNNs), and morphological measurement.
METHODS
MR vessel wall images acquired using DANTE-SPACE sequences and corresponding time-of-flight-MRA images of 67 subjects (including 47 healthy volunteers and 20 patients with atherosclerosis) were included in this study. The centerline of the vessel was firstly extracted from the MRA images and copyed to the 3D MR vessel wall images through the registration relationship between the MRA images and the MR vessel wall images to extract, straighten, and reconstruct interested vessel segments into 2D slices. Then a complete CNN-based Unet-like method was used to automatically segment the vessel wall to obtain quantitative morphological measurements such as maximum wall thicknesses and normalized wall index (NWI).
RESULTS
The proposed automatic segmentation network was trained and validated with 11,735 slices and tested on 2517 slices. The method showed satisfactory agreement with manual segmentation method. The Dice coefficients of intracranial arteries were 0.90 for lumen and 0.78 for vessel wall, while the Dice coefficients of extracranial arteries were 0.90 for lumen and 0.82 for vessel wall. The maximum wall thickness and NWI obtained from the proposed automatic method were slightly larger than those obtained from the manual method for both intra- and extracranial arteries. However, there was no significant difference of the quantitative measurements between the two methods ( > 0.05). In addition, the automatically measured NWI of plaque slice was significantly larger than that of normal slice.
CONCLUSION
We propose an automatic analysis method of MR vessel wall images, which can realize automatic segmentation of intra- and extracranial vessel wall. It is expected to facilitate large-scale arterial vessel wall morphological quantification.
ADVANCES IN KNOWLEDGE
We have proposed an automatic method for analysis of intra- and extracranial MR vessel wall images simultaneously based on CNN, which can facilitate large-scale quantitative analyses of vessel walls.
Topics: Humans; Neural Networks, Computer; Arteries; Magnetic Resonance Imaging; Plaque, Atherosclerotic; Atherosclerosis; Imaging, Three-Dimensional
PubMed: 36018822
DOI: 10.1259/bjr.20210031 -
Journal of Current Ophthalmology 2022To compare Pentacam indices in normal eyes with different corneal thicknesses.
PURPOSE
To compare Pentacam indices in normal eyes with different corneal thicknesses.
METHODS
It is a retrospective observational study. Ninety-six normal eyes of 96 patients who were referred for refractive surgery in a tertiary university-based hospital from October 2015 to April 2019 were recruited consecutively. Corneal keratometry as well as Pentacam's software Belin-Ambrósio Enhanced Ectasia Display (BAD) parameters including pachymetry progression indices (PPIs), maximum Ambrosio's relational thickness (ART-max), corneal elevations, normalized deviations, BAD total deviation value (BAD-D), and anterior surface indices were measured by Pentacam HR (Type 70900). The included were classified as thin (26 eyes), average (45 eyes), and thick (25 eyes) corneas with the thinnest point thickness of ≤496 μm, 497-595 μm, and ≥596 μm, respectively. The specificities of all parameters were calculated based on routine cut-off values.
RESULTS
The refraction, keratometry, and elevations were not different ( > 0.05). All PPIs (minimum, average, and maximum) of thick corneas were significantly lower than average and thin corneas ( < 0.001). ART-max increased by thickening of the cornea ( < 0.001). BAD-D score and normalized indices of pachymetric parameters decreased with the increase of thickness ( < 0.001), while specificities of all indices increased with corneal thickening. More than 96% of thick corneas were classified as normal PPI-max (24/25), ART-max (25/25), and BAD-D (25/25), while nearly <54% of thin corneas (14/26 for PPI-max, 9/26 for ART-max, and 12/26 for BAD-D) were normal.
CONCLUSIONS
The pachymetry-related indices and BAD-D were different among normal corneas with various thicknesses. The specificities of PPIs, ART-max, and BAD-D of thin corneas were lower than in thick corneas.
PubMed: 36147272
DOI: 10.4103/joco.joco_249_21 -
Medical Physics Aug 2022Emerging multi-pixel X-ray source technology enables new designs for X-ray imaging systems. The power of multi-pixel X-ray sources with a fixed anode is limited by focal...
BACKGROUND
Emerging multi-pixel X-ray source technology enables new designs for X-ray imaging systems. The power of multi-pixel X-ray sources with a fixed anode is limited by focal spot power density.
PURPOSE
The purpose of this study is to optimize the W-diamond target and predict its performance in multi-pixel X-ray sources.
METHODS
X-ray intensity and energy deposition in the W-diamond target with different thicknesses of tungsten film and incident electron energies was calculated with the Geant4 Monte Carlo toolkit. COMSOL Multiphysics software was used to analyze the transient and stationary heat transfer in the thin-film W-diamond target. The maximum tube power and X-ray output intensity were predicted for both transmission and reflection target configurations.
RESULTS
The maximum focal spot power density was limited by either the graphitization of the diamond substrate or the melting point of the W target. With optimal W-target thickness, the maximum transmission X-ray intensities are about 40%-50% higher than the maximum reflection intensities. Thin-film W-diamond targets allow four to five times more maximum power input and produce six to seven times higher transmission X-ray intensity in continuous mode compared with conventional reflection W thick targets. Depending on the focal spot size, reducing the X-ray pulse duration can further enhance the tube power.
CONCLUSIONS
Multi-pixel X-ray sources using this W-diamond target design can produce significantly higher X-ray output than traditional thick tungsten targets without major modification of the tube design.
PubMed: 35587460
DOI: 10.1002/mp.15722 -
Biofilm Dec 2022The accumulation of protons in electro-active biofilms (EABfs) has been reported as a critical parameter determining produced currents at the anode since the very...
The accumulation of protons in electro-active biofilms (EABfs) has been reported as a critical parameter determining produced currents at the anode since the very beginning of the studies on Bio-electrochemical systems (BESs). Even though the knowledge gained on the influence of this parameter on the produced currents, its influence on EABfs growth is frequently overlooked. In this study, we quantified EABfs thicknesses in real-time and related them to the produced current at three buffer concentrations, two anode potentials and two acetate concentrations. The thickest EABfs (80 μm) and higher produced currents (2.5 A.m) were measured when a 50 mM buffer concentration was used. By combining the measured EABfs thicknesses with the pH in the anolyte, a simple model was developed to identify buffer limitations. Buffer limited EABfs with thicknesses of 15 and 42 μm were identified at -0.3 V vs Ag/AgCl when 10 and 50 mM buffer concentrations were used, respectively. At -0.2 V vs Ag/AgCl, the thicknesses of buffer limited EABfs decreased to 13 and 20 μm, respectively. The model also estimated buffer and acetate diffusion rates in EABfs and allowed to determine the boundary between a buffer and acetate limited EABfs. The diffusion rates reported in this study and the definition of the boundary between buffer and acetate limited EABfs provide a powerful tool to avoid limitations, leading to higher produced currents at the anode.
PubMed: 36425753
DOI: 10.1016/j.bioflm.2022.100092 -
Frontiers in Medicine 2021To investigate single-photon emission computed tomography/computed tomography (SPECT/CT) for assessing inflammation in the extraocular muscles (EOMs) and predicting the...
To investigate single-photon emission computed tomography/computed tomography (SPECT/CT) for assessing inflammation in the extraocular muscles (EOMs) and predicting the therapeutic efficacy of periocular glucocorticoid therapy (PGT) for Grave's ophthalmopathy (GO). A total of 412 eyes from 206 patients with GO referred for Tc-DTPA orbital SPECT/CT were enrolled. Fourteen age- and gender-matched healthy controls (28 eyes) were included. The thickness and uptake ratio (UR) of four EOMs were derived from SPECT/CT. Eighty-six eyes from patients with GO patients received PGT. Changes in SPECT/CT parameters were evaluated between the pre- and post-treatment. 195 eyes and 217 eyes were classified as active and inactive stages by clinical activity score (CAS). Values of the thickness and UR of each EOM, T, and U were all significantly higher in the active GO than in the inactive GO and controls ( < 0.01). Among the 86 eyes (48 GO patients) included in the efficacy analysis, 56 eyes and 30 eyes were classified as responders and non-responders. Values of thicknesses and UR of each EOM, the maximum thickness (T), and the maximum UR (U) all dropped following PGT in the responders ( < 0.01). Logistic regression analysis identified the U as an independent predictor for the responders ( < 0.01). Moreover, the U demonstrated incremental predictive value over clinical characters and CAS, as evidenced by the improved area under the curve (0.85 vs. 0.78) and global chi-square (34.12 vs. 18.1). Tc-DTPA SPECT/CT has the potential to assess inflammatory activity by detecting the involvement of EOMs in GO. Pre-treatment UR provides independent and incremental values for the prediction of PGT treatment response.
PubMed: 34977092
DOI: 10.3389/fmed.2021.791131