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Statement of Problem: Fully stabilized monolithic zirconia (FSZ) has been developed as an alternative to zirconia veneered with porcelain. However, how sintering conditions might affect its microstructure and optical and mechanical properties is unclear., Purpose: The purpose of this in vitro study was to determine the effect of different sintering temperatures on the microstructure and optical and mechanical properties of FSZ., Material and Methods: Bar-shaped FSZ specimens were prepared and divided into 2 groups (n=15) according to final sintering temperatures (1450 °C and 1600 °C). The average reflectance, opacity, translucency parameter, and sum of light absorption-scattering values were obtained by using a spectrophotometer, and ΔE 00 was calculated. The 3-point bend test was performed in a universal testing machine. Scanning electron microscopy (SEM) was conducted for microstructure analysis. Crystalline phase quantification was obtained by X-ray diffraction (XRD). Data were analyzed by using D'Agostino-Pearson and Student t tests (α=.05)., Results: A significant difference was detected in the reflectance and sum of light absorption-scattering values between the 2 groups. The translucency parameter, opacity, and flexural strength showed no statistical differences. ΔE 00 was 0.98. XRD indicated cubic (47.41% for 1450 °C; 46.04% for 1600 °C) and tetragonal content (52.59% for 1450 °C; 53.96% for 1600 °C). No monoclinic content was found. SEM images showed more definite grain boundaries in the 1600-°C group. Mean grain size was 0.49 μm for the 1450-°C group and 1.99 μm for the 1600-°C group., Conclusions: Higher sintering temperatures increased the grain size but did not change the crystal phase concentration. A significant difference was found in the reflectance and sum of light absorption-scattering, but no differences were found among the translucency parameter, opacity, or flexural strength., (Copyright © 2019 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate changes in color and translucency of stained and glazed monolithic lithium disilicates and zirconia after toothbrushing with conventional or whitening dentifrices followed by thermocycling. Materials and Methods: Samples (n = 20/material) from CAD/CAM (IPS e.max CAD [EC]) and pressable (IPS e.max Press [EP]) lithium disilicates and 5Y-PSZ zirconia (Prettau 4 Anterior [PA]) were prepared and received staining and glazing procedures. Aging was performed by toothbrushing with conventional (n = 10) or whitening (n = 10) dentifrices, followed by thermocycling simulating 5, 10, and 15 years. Color coordinates L*, a*, b*,, and C* and hº values were assessed with a spectrophotometer at baseline and after each aging period to calculate color changes (ΔE00), lightness (ΔL*), and translucency parameter (TP). Data were analyzed using three-way repeated measures ANOVA's followed by Sidak post-hoc test (α = .05). Results: When comparing the dentifrices, EC and EP produced the greatest ΔE00 after 15 years with the whitening dentifrice (P < .05). Regardless of the dentifrice, PA showed greater ΔE00 than EC after 10 years (P < .05). When comparing the aging periods, EC and PA did not show differences in ΔE00 for both dentifrices (P ≥ .05). EC and EP produced an increased ΔL* after 15 years in the whitening group (P < .05). In the whitening groups, the ΔL* values of PA differ (P < .005) from those of lithium disilicates. Regardless of the experimental group, the TP values followed the inequality: PA < EC < EP (P < .05). Conclusions: Overall, the color of stained and glazed monolithic lithium disilicates and zirconia changed under aging with greater effects for whitening dentifrice. Aging did not influence translucency. [ABSTRACT FROM AUTHOR]

Rifaximin, an oral antimicrobial drug, is marketed as 200-mg tablets. The daily dose ranges from 600 mg (1 tablet 3 times a day) to 800 mg (2 tablets twice a day). It is used for a wide range of ages, from adults to children, since it is indicated for the treatment of hepatic encephalopathy, travelers' diarrhea, irritable bowel syndrome, Clostridium difficile, ulcerative colitis, and acute diarrhea. The success of pharmacotherapy will depend on correct fulfillment of drug administration; however, it becomes difficult when the tablets are large and the doses are frequent. Rifaximin belongs to class IV according to the Biopharmaceutic Classification System (BCS), meaning that it is both poorly soluble and poorly permeable. Thus, in this study, solubility of rifaximin was improved by its complexation to β-cyclodextrin by (i) phase solubility diagram, (ii) malaxation, and (iii) decreasing particle size by wet milling. Improved solubility provides lower doses and facilitates compliance with pharmacotherapy. The products formed were analyzed by spectrophotometry in the infrared region (FT-IR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). Also, their solubility and microbiological activity were determined. The products obtained in all techniques were more soluble than the free drug; they presented higher thermal stability and antimicrobial potency was approximately 100% with all the formulations. It is important to highlight that the treatment failure not only affects the quality of life of the patients, but also contributes significantly to the economic burden of the health system. Therefore, these findings are extremely interesting, both from a technological and financial point of view.

Objectives: To evaluate the effect of hydrothermal aging (H), mechanical cycling (M), and the combination of hydrothermal plus mechanical cycling (H+M) on biaxial flexural strength (BFS) and microstructure of two monolithic zirconias, indicated for anterior (AMZ) or posterior restorations (PMZ) and a conventional zirconia (IZr)., Methods: Disc specimens of each material (n=12) were submitted to: i) H (8h in autoclave at 134°C); ii) M (10 6 cycles, at 40% of BFS); and iii) H+M. BFS was measured (ISO-6872) and Weibull modulus (m) and the characteristic strength (σ 0 ) were calculated. crystalline phase composition analyzed by XRD, and grain size measured by MEV analysis., Results: XRD analysis showed AMZ was not susceptible to monoclinic transformation in any treatment. Conventional zirconia (IZr) and PMZ had monoclinic transformation only after H and H+M. BFS of AMZ was lower than PMZ and IZr. Cubic phase was found in all conditions for AMZ and IZr, while it was identified in PMZ only after H and H+M. BFS of AMZ was affected by M and H+M. For IZr and PMZ the unique difference detected in BFS was in the comparison of H to M. H treatment induced lower Weibull modulus, but characteristic strength was compatible with the BFS results. AMZ grain size (μm 2 ) was 8.6 times larger than PMZ grains, and 13.6 times larger than IZr grains., Conclusions: AMZ showed the largest mean grain size, had the lowest BFS values, and was affected when mechanical cycling was involved. Monoclinic transformation was not found in any treatment for AMZ, but was found in IZr and PMZ when hydrothermal aging was used alone or when combined with mechanical cycling. PMZ showed similar behavior to the IZr. H induced to higher fracture probability., Clinical Significance: Translucent monolithic dental zirconia available on the market may behave differently under simulated oral aging. The relationship between composition and microstructure determines their properties presumably, and clinical performance., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

This study evaluated microstructural and crystallographic phase changes after grinding (G) and regeneration firing/anneling (R) of Y-TZP ceramics. Thirty five bars (Lava TM and Ice Zirkon) were divided: Y-TZP pre-sintered, control (C), regeneration firing (R), dry grinding (DG), dry grinding+regeneration firing (DGR), wet grinding (WG) and wet grinding+regeneration firing (WGR). Grinding was conducted using a diamond bur and annealing at 1,000°C. The microstructure was analyzed by SEM and the crystalline phases by X-ray diffraction (XRD). XRD showed that pre-sintered specimens contained tetragonal and monoclinic phases, while groups C and R showed tetragonal, cubic and monoclinic phases. After grinding, the cubic phase was eliminated in all groups. Annealing (DGR and WGR) resulted in only tetragonal phase. SEM showed semi-circular cracks after grinding and homogenization of particles after annealing. After grinding, surfaces show tetragonal and monoclinic phases and R can be assumed to be necessary prior to porcelain layering when grinding is performed.

Statement of Problem: The changes that occur after brushing yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) are unknown. These changes may favor the retention of microorganisms and chemisorption of water, impairing its longevity., Objective: The purpose of this in vitro study was to evaluate the effects of a whitening dentifrice on Y-TZP surfaces after simulating 10 years of brushing., Material and Methods: Seventy-two bar-shaped specimens (20×4×1.2 mm) were divided into 4 groups: storage in distilled water (SW, control), brushing with distilled water (BW), brushing with dentifrice (BD), and brushing with whitening dentifrice (BWD). Brushing was conducted using a linear brushing machine (878400 cycles, 0.98 N, soft toothbrush). The mean roughness (Ra) was analyzed with a profilometer and the superficial topography with scanning electron microscopy (SEM) at baseline and after treatment. Crystalline phases were characterized using x-ray diffraction. Baseline and posttreatment Ra were analyzed using the 1-way ANOVA and Tukey HSD multiple comparison test; the paired t test was used for intragroup comparison (all α=.05)., Results: The Ra (μm) means (before/after treatment) were SW 0.28/0.28; BW 0.32/0.31; BD 0.28/0.36; BWD 0.30/0.20. No statistically significant difference was found for Ra at baseline (P=.108) than for posttreatment results (P<.001); the BD group had higher Ra values when compared with baseline (P=.019); the BWD group had the lowest values (P<.001). The BD surfaces showed pronounced scratches and detachment of the surface, while BWD showed smoother surfaces; similar crystallographic results among groups were observed., Conclusions: Brushing Y-TZP with conventional dentifrice increased roughness, while brushing with whitening dentifrice reduced roughness. Neither dentifrice changed the crystallographic phases after brushing., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Most ceramic abutments are fabricated from yttria-stabilized tetragonal zirconia (Y-TZP). However, Y-TZP undergoes hydrothermal degradation, a process that is not well understood., Purpose: The purpose of this in vitro study was to assess the effects of artificial aging conditions on the fracture load, phase stability, and surface microstructure of a Y-TZP abutment., Material and Methods: Thirty-two prefabricated Y-TZP abutments were screwed and tightened down to external hexagon implants and divided into 4 groups (n = 8): C, control; MC, mechanical cycling (1×10(6) cycles; 10 Hz); AUT, autoclaving (134°C; 5 hours; 0.2 MPa); and TC, thermal cycling (10(4) cycles; 5°/55°C). A single-load-to-fracture test was performed at a crosshead speed of 0.5 mm/min to assess the assembly's resistance to fracture (ISO Norm 14801). X-ray diffraction (XRD) analysis was applied to observe and quantify the tetragonal-monoclinic (t-m) phase transformation. Representative abutments were examined with high-resolution scanning electron microscopy (SEM) to observe the surface characteristics of the abutments. Load-to-fracture test results (N) were compared by ANOVA and Tukey test (α=.05)., Results: XRD measurements revealed the monoclinic phase in some abutments after each aging condition. All the aging conditions reduced the fracture load significantly (P<.001). Mechanical cycling reduced the fracture load more than autoclaving (P=.034). No differences were found in the process of surface degradation among the groups; however, the SEM detected grinding-induced surface flaws and microcracks., Conclusions: The resistance to fracture and the phase stability of Y-TZP implant abutments were susceptible to hydrothermal and mechanical conditions. The surface microstructure of Y-TZP abutments did not change after aging conditions., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Rifaximin is a gut-selective oral antimicrobial that has no systemic adverse effects compared with placebo. It is used for the treatment of hepatic encephalopathy, traveler's diarrhea, irritable bowel syndrome, Clostridium difficile infection, ulcerative colitis, and acute diarrhea. The crystalline form present in rifaximin, α, has minimal systemic absorption compared to the amorphous form. The objective of this study was to obtain polymorphic forms of rifaximin using recrystallization processes. The forms were characterized and studied by thermal analysis, X-ray powder diffraction, scanning electron microscopy, and solubility testing. Six polymorphic forms of rifaximin, designated I-VI, were obtained by the crystallization process by evaporation of the solvent. Some polymorphic forms obtained in this work may not have the same excellent tolerability as the reference medicine; therefore, studies such as these are extremely important and point to the need for greater requirements by the regulatory agencies overseeing polymorph analysis of the raw materials used in the manufacture of medicines marketed globally. These analyses are not required in the majority of official compendia. Partnerships among industries, research centers, and universities would be a viable way to consolidate research in this area and contribute to improving the quality of solid drugs.

Background and aim: Achieving the aesthetic standards in tooth-colored restorative materials requires close attention to their color, translucency, and resistance to discoloration. This study aimed to evaluate the effect of sintering temperature on color stability and translucency in zirconia systems with low, high, and ultra-high translucencies. Methods: This experimental study was conducted on 60 zirconia disks with low, high and ultra-high translucencies (n = 20 per group), each group divided into subgroups to be sintered at either 1450°C or 1550°C (n = 10 per subgroup). Baseline color and translucency parameters were measured, the specimens were then immersed in coffee solution for 30 days, and the measurements were repeated post-immersion. Changes in color (ΔE) and translucency (ΔTP) were calculated via CIELAB formula and compared by using two-way ANOVA and Tukey's post hoc test (α = 0.05). Results: Results of two-way ANOVA showed that the ΔE was significantly different among the three zirconia translucencies (P<0.001), but no significant difference was found between the two sintering temperatures (P = 0.712). Additionally, the interaction between zirconia type and sintering temperature was not statistically significant for ΔE (P = 0.264). The low-translucency group showed significantly greater ΔE than the high-translucency and ultra-high-translucency groups (P<0.05), while the high- and ultra-high-translucency groups were not significantly different in this regard (P>0.05). Regarding the ΔTP, two-way ANOVA showed that the difference was not statistically significant either among the three zirconia types (P = 0.4430) or between the two sintering temperatures (P = 0.4544). Nor was the interaction between zirconia type and sintering temperature statistically significant (P = 0.5505). Conclusion: It was concluded that sintering temperature had no effect on color and translucency changes after immersion in coffee. Whereas zirconia type significantly affected the color changes after immersion in coffee; with the higher-translucency zirconia types being significantly more color-stable than the low-translucency zirconia. [ABSTRACT FROM AUTHOR]

Bacterial nanocellulose (BNC) currently has emerged as a potential biopolymer that can be used for various industrial applications. However, the major concern is the limitation of the bacteria used for BNC production on a larger scale. This study aimed to isolate and identify potential nanocellulose-producing bacteria from pineapple wastes. In this study, 11 isolates were screened and the F1 isolate, which produced the highest BNC yield was chosen for 16S rRNA sequencing. Based on the 16S rRNA analysis, Comamonas terrae YSZ sp. (OQ592726.1) was the best BNC producer with 1.68 ± 0.19 g/L yield. The physicochemical characteristics from FESEM analysis revealed that C. terrae YSZ sp. produced amorphous BNC, with fewer nanofibrils. The XRD analysis showed that the BNC produced had a 19.3% of crystallinity index. To the best of our knowledge, this is the first work reporting the isolation of C. terrae YSZ sp. from pineapple wastes with more amorphous regions providing an interesting alternative for heavy metal removal potentials. [ABSTRACT FROM AUTHOR]

Finasteride (FNT) is a drug that inhibits human enzyme type II 5α-reductase that metabolizes testosterone into dihydrotestosterone. There are two enantiotropic polymorphs with known crystal structure: designated as forms I and II. Identification and control of these polymorphic forms in mixtures can be performed using X-ray powder diffraction (XRPD) data and Rietveld method (RM). As experimental conditions may limit the detection of minority phases in mixtures, it is interesting to show what are these limits for some usual and one high-resolution equipment. So, in this work, we discuss the parameters to find the limit of the detection in binary mixtures of forms I and II of FNT according to each experimental condition. The samples analyzed were binary mixtures prepared with anhydrous polymorphs of the drug FNT. These samples were measured in four diffractometers with different experimental condition. These equipments represent the main resolutions generally used for drug analysis by XRPD. For the development of this work, a batch of form I was obtained pure, and another batch with forms I and II was used to obtain pure form II by heat treatment. Depending on the experimental condition, the polymorphs could be detected in a proportion as low as 0.5 wt%. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:3567-3575, 2014., (© 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.)

The present work shows that the heated carbamazepine (CBZ) powder form III can be described as purely triclinic form I or a mixture of triclinic form I and monoclinic form III, depending on the resolution of the X-ray diffraction equipment used. Visual identification of the minor phase is possible when high-resolution synchrotron light is used. Quantitative phase analyses of CBZ forms I and III, after thermal treatment, were performed by using both synchrotron and conventional copper rotating anode X-ray powder diffraction data and the Rietveld method. Also, the Rietveld method could be adequately applied to determine the phase percentage in the heated material, even when usual resolution data are acquired., (Copyright © 2011 Wiley-Liss, Inc. and the American Pharmacists Association)

The crystal structure determination of mebendazole form A, an anthelmintic drug, was performed for the first time by applying the DASH software program to synchrotron X-ray powder diffraction data, and supported by a satisfying Rietveld fit. This polymorph of mebendazole crystallizes in a triclinic (P1) space group, with unit-cell parameters a = 5.5044(2) A, b = 11.2872(2) A, c = 12.5276(5) A, alpha = 66.694(2) degrees, beta = 82.959(2) degrees, gamma = 78.443(2) degrees, V = 699.52(5) A(3), Z = 2, M = 295.293 g mol(-1), rho(calc) = 1.4021 g cm(-3), and rho(meas) = 1.3935(66) g cm(-3), which were obtained by means of the unit-cell formula weight and a picnometric measurement, respectively. The goodness-of-fit and R-factors were, respectively: chi(2) = 1.746, R(F)(2) = 1.69%, R(wp) = 5.72%, and R(p) = 4.37%. A weak nonclassical hydrogen bond involving the atoms N(3)-H(23)...O(11) may be responsible for the greater stability of the polymorphic form A of mebendazole due to the strongest electronegativity of nitrogen., (2009 Wiley-Liss, Inc. and the American Pharmacists Association)

Copyright of International Journal of Computerized Dentistry is the property of Quintessence Publishing Company Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the industrial application of bacterial cellulose (BC), the yield becomes a crucial factor because it drives the selling price of BC. A Box–Behnken experimental design with three components and three levels was employed to create seventeen samples. A response surface method was then used to optimize the BC yield from the most relevant parameters, including incubation temperature, medium shaking intensity, and nitrogen supply pH. Fourier transform infrared (FTIR) analysis proved that BC was pure. By analyzing BC morphology using scanning electron microscopy (SEM), rod-like microfibrils with an average diameter of 6.5 were revealed. X-ray diffraction (XRD) tested the crystalline size and crystallinity and found 4.7 nm and 69%, respectively. Thermal transition and stability were assessed using a differential scanning calorimeter (DSC) and a thermogravimetric analyzer (TGA). For the manufacture of BC composite hydrogel, a chemical test method was used to determine the solubility of BC. This study aimed to identify the ideal circumstances for using leftover sweet lime pulp for biomedical applications to produce reasonably priced and effective BC. At 28.87 °C, 125.91 rpm shaking frequency, and 5.65 pH, a sweet lime pulp waste medium produced the highest yield of BC, three times greater than the yield in a Hestrin–Schramm medium under static circumstances. [ABSTRACT FROM AUTHOR]

Object: This study aimed to investigate the changes in the translucency and color of four different multi-layered zirconia materials when the sintering temperature were inaccurate. Materials and methods: Two hundred zirconia samples (11 × 11 × 1.0 mm) of four multi-layered zirconia, Upcera TT-GT (UG), Upcera TT-ML (UM), Cercon xt ML (CX), and Lava Esthetic (LE), were divided into five subgroups according to the sintering temperature: L1 (5% lower temperature), L2 (2.5% lower temperature), R (recommended sintering temperature), H2 (2.5% higher temperature), H1 (5% higher temperature). After sintering, color coordinates were measured. Then the translucency parameter (TP) values, and the color differences (between the inaccurate sintering temperature and the recommended temperature) of each zirconia specimen were calculated. Statistical analysis was performed by using three-way ANOVA tests, the one-way ANOVA, and Tukey's post hoc test. Results: Three-way ANOVA results showed that material type, sintering temperature, specimen section, and their interactions significantly influenced the TP values (except for the interactions of specimen section and sintering temperature) (P <.05). TP values of zirconia specimens were significantly different in the inaccurate sintering temperatures (P <.05), except for the cervical and body sections of UG group (P >.05). Compared with recommended sintering temperature, higher sintering temperature caused higher TP values for CX, but lower for LE. Three-way ANOVA results showed that material type, sintering temperature, and their interactions significantly influenced the ∆E00 values (P <.05). There were no significant differences in ∆E00 values of UM and CX groups at different inaccurate sintering temperatures, and were clinical imperception (except for UM-L1) (∆E00 < 1.25). ∆E00 values of all zirconia specimens showed clinically acceptable (∆E00 < 2.23). Conclusion: The deviations in sintering temperature significantly influenced the translucency and color of tested multi-layered zirconia. The trends of translucency in the multi-layered zirconia depended on material type and the color changes of all zirconia materials were clinically acceptable at inaccurate sintering temperatures. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Health Sciences (2447-8938) is the property of Unopar Cientifica Ciencias Biologicas e da Saude and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: To compare the effect of thermomechanical aging on implant abutment color change when using different abutment backgrounds. Materials and Methods: In this study, three separate experimental groups (n = 10) with different implant abutment materials were used: zirconia, modified polyether ether ketone (MPEEK), and polyether ketone ketone (PEKK). Equal-sized glass-ceramic incisor crowns were cemented to the abutments using transparent dual-curing resin cement. The specimens were then subjected to the thermomechanical aging process for the clinical equivalent of 5 years of use. The color values of each specimen in the middle third and the incisal third were recorded by a digital spectrophotometer in the CIE L*a*b* color coordinates both before and after the aging process. Color differences between groups were compared using one-way analysis of variance (ANOVA), while Tukey test was used to compare differences within the groups (P = .05). Results: In terms of color change (Î"E00) values, the zirconia group was found to show statistically more color changes only in the middle third (P < .000), but there was no significant difference between the the MPEEK and PEKK groups. In all groups, the Î"E00 value was clinically acceptable (Î"E00 < 1.8). Conclusion: After the aging process, high-performance polymer abutments caused less color change than zirconia. Therefore, esthetically satisfying results can be obtained in the anterior region, especially when highly translucent crown materials are used. [ABSTRACT FROM AUTHOR]

Purpose: To experimentally assess the effect of regenerative heat treatment (HT) on yttria-stabilized tetragonal zirconia polycrystalline ceramic (Y-TZP) to guarantee veneer adhesion strength. Materials and Methods: One surface of bar-shaped Y-TZP specimens was ground (G) with a diamond stone, while the control samples (C) were not. Groups C900 and G900 were submitted to HT at 900°C for 60 min, whereas groups C1000 and G1000 were submitted to HT at 1000°C for 30 min. The treated surfaces were characterized by x-ray diffractometry (XRD), scanning electron microscopy (SEM), and optical and mechanical profilometry. The energy release rate through interface fracture was determined by a four-point bending test on notched Y-TZP veneered specimens. XRD was refined by the Rietveld method, mean roughness (Ra) and energy release rate were submitted to two-way ANOVA (a = 0.05), and the images were analyzed descriptively. Results: The monoclinic phase (vol%), means of Ra (µm), and the energy release rate (J/m2) were, respectively: C = 1.2/0.17/6.8, C900 = 0.0/0.18/6.6, C1000 = 0.0/0.18/7.6, G = 2.6/1.16/8.3, G900 = 0.0/1.07/8.0, and G1000 = 0.0/1.01/5.7. The surface fraction of monoclinic zirconia increased by grinding and decreased by HT. Ra also increased after grinding (p < 0.005) but remained unaltered after HT (p = 0.22). Increased irregularity was observed in the G groups and a subtle smoothing of the surface after HT. After the fracture of the bilayers, a residual amount of porcelain could be seen on the zirconia surface in all groups. The energy release rate was statistically equal among all groups (p > 0.05). Conclusion: Heat treatment after grinding completely restored the tetragonal phase of zirconia without altering the energy release rate during interfacial fracture. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effects of different hydrofluoric acid (HF) concentrations and etching times on the surface topography, roughness, and resin bond strength to ceramic-coated zirconia (CC), and to compare them with the effects of alumina air-abrasion combined with 10-MDP (AA). Materials and Methods: AA and CC specimens were divided into 12 groups (N = 10). The CC groups were etched with HF at different concentrations (5% or 9.5%) for various durations (0 min, 1 min, 2 min, 3 min, 5 min or 10 min). The surface morphology was analyzed using SEM. Energy-dispersive x-ray spectroscopy (EDS) and x-ray diffraction (XRD) were performed for chemical and crystalline-phase analyses. Surface roughness (Ra) and shear bond strength (SBS) were recorded and statistically analyzed. Results: The SBS of CC groups initially increased, but then decreased with etching time for both HF acid concentrations. The 9.5% HF group displayed more marked topographical changes and higher Ra compared with the 5% HF group for the same etching period. Mean SBS was lower in the AA group compared with the CC groups etched with 5% HF for 2-10 min and 9.5% HF for 1-3 min (p < 0.05). Conclusions: Different HF concentrations and etching times influenced the surface topography, roughness, and resin bond strength of/to ceramic-coated zirconia. Etching with 5% HF for 5 min and with 9.5% HF for 2 min, respectively, provided the highest SBS. [ABSTRACT FROM AUTHOR]

This study aimed to clarify the effects of multiple firings on the translucency, crystal structure, and mechanical strength of highly translucent zirconia. Four types of highly translucent zirconia (LAVA Esthetic, LAVA Plus, KATANA Zirconia STML, and KATANA Zirconia HTML) were fired three times at three different temperatures, and the translucency, crystal structure, and flexural strength were evaluated before and after firing. The translucency was statistically compared using repeated-measures analysis of variance; the zirconia phase composition was assessed using X-ray diffraction followed by Rietveld analysis; and the biaxial flexural strength was assessed using Weibull analysis. The translucency of LAVA Esthetic and KATANA Zirconia HTML decreased significantly after firing, and the crystal composition of LAVA Plus and KATANA Zirconia HTML changed after multiple firings, whereas multiple firings did not affect the biaxial flexural strength of any samples. Thus, multiple firings may affect the optical properties of highly translucent zirconia [ABSTRACT FROM AUTHOR]

URPOSE. To investigate the effect of sintering programs and surface treatments on surface properties, phase transformation and flexural strength of monolithic zirconia. MATERIALS AND METHODS. Zirconia specimens were sintered using three distinct sintering programs [classic (C), speed (S), and superspeed (SS)] (n = 56, each). One sample from each group underwent scanning electron microscopy (SEM) and grain size analysis following sintering. Remaining samples were divided into five subgroups (n = 11) based on the surface treatments: control (CL), polish (P), glaze (G), grind + polish (GP), and grind + glaze (GG). One sample from each subgroup underwent SEM analysis. Remaining samples were thermally aged. Monoclinic phase volume, surface roughness, and three-point flexural strength were measured. Monoclinic phase volume and surface roughness were analyzed by Kruskal-Wallis and Dunn tests. Flexural strength was analyzed by two-way ANOVA and Weibull analysis. The relationships among the groups were analyzed using Spearman's correlation analysis. RESULTS. Sintering program, surface treatment, and sintering × surface treatment (P = .010) affected the monoclinic phase volume, whereas the type of surface treatment and sintering × surface treatment affected the surface roughness (P < .001). Type of sintering program or surface treatment did not affect the flexural strength. Weibull analysis revealed no significant differences between the m and so values. Monoclinic phase volume was positively correlated with surface roughness in the SGG and SSP groups. CONCLUSION. After sintering monolithic zirconia in each of the three sintering programs, each of the surface treatments can be used. However, for surface quality and aging resistance, G or GG can be recommended as a surface finishing method. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the influence of repetitive autoclaving on diamond burs fabricated via different methods.Materials and Methods: A total of 96 diamond burs were divided into 12 groups according to fabrication method (single-element electroplating, multi-element electroplating, or brazing) and number of times autoclaved (0, 5, 10, or 15). The surface characteristics and components of the diamond burs were examined using scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (XPS). The cutting efficiency of the diamond burs was tested with a constant-pressure cutting appliance.Results: Compared to the nonautoclaved group, the cutting efficiency of the multi-element and single-element electroplated diamond burs decreased significantly after autoclaving 5, 10, and 15 times (P < .05). The cutting efficiency of the brazed diamond burs started to decrease significantly after 10 cycles (P < .05). Cracks appeared on the surfaces of multi-element electroplated diamond burs after 10 and 15 cycles, but were absent in the single-element electroplated and brazed diamond burs. A reduction of nickel was detected in the multi-element electroplated and brazed diamond burs, but not in the single-element electroplated diamond burs.Conclusion: Repetitive autoclaving could reduce the cutting efficiency of diamond burs. The extent of the reduction was related to fabrication method and number of autoclaving times, suggesting that used diamond burs should be separately autoclaved to avoid shortening the life spans of unused ones. [ABSTRACT FROM AUTHOR]

Zr-based bulk metallic glasses (BMGs) are characterized by excellent glass-forming ability, combined with superior mechanical properties. However, oxygen impurities degrade both these aspects as oxides serve as heterogeneous nucleation sites during solidification. Rare-earth elements (REEs) are known to be good oxygen scavengers, binding oxygen to less harmful forms. The most stable rare-earth oxide (REO) is M2O3, which occurs in three polymorphic forms, depending on the radius of metal cation: cubic, hexagonal, and monoclinic. Here, we show the effect of Sc, Y, Lu, Nd, and Gd additions in relation to the oxygen content on the glass-forming ability of the Zr52.5Cu17.9Ni14.6Al10Ti5 alloy. Microscopic observations (SEM) supported by chemical analysis (EDS, WDS), structure identification (XRD), and thermal analysis (DTA) were carried out. The critical diameter for glass formation (Dc) in the high oxygen alloy doped with cubic oxide-forming elements (Sc, Y, and Lu) can be even higher (Dc = 9 mm) compared to the undoped alloy synthesized from low oxygen components. Therefore, we have demonstrated that it is feasible to produce BMG using low-purity constituents with REE-based oxygen scavengers. This bridges the gap between laboratory development and cost-effective commercial applications. [ABSTRACT FROM AUTHOR]

The pathways of dehydration reaction of both calcium atorvastatin trihydrate (CAT) and grinded CAT were investigated using CRTA technique under controlled residual water vapor pressure of 5 hPa using complementary analysis techniques, namely TG, DSC and XRD. The results show that the studied sample is a pure atorvastatin in its trihydrated form and that, under CRTA conditions, it dehydrates in three separated steps between 261 and 393 K, each corresponds to the loss of one water molecule. On the other hand, the grinded CAT dehydrates in one step. From the duration of the CRTA experiment and the X-ray diffraction technique, we have showed that the grinding partially dehydrates CAT, to obtain calcium atorvastatin 1.5 H2O, while decreasing its crystallinity. Also, examination by X-ray diffraction technique of the CRTA final products of both, CAT and grinded CAT, showed that the anhydrous phase of CAT is crystallized, whereas the one of the grinded CAT is amorphous. The apparent activation energies corresponding to the dehydration steps of intact CAT (39 kJ mol−1 and 34 kJ mol−1) and grinded CAT (126 kJ mol−1 and 289 kJ mol−1) were obtained by means of two CRTA curves realized at two different reaction rates without any hypothesis on the kinetic model of the reaction. [ABSTRACT FROM AUTHOR]

Objectives: The objective of this study was to prepare carboplatin loaded cubosomes using high sheer homogenization technique. Materials and Methods: The cubosomes were prepared using Glyceryl Monooleate (GMO) as a lipophilic carrier along with pluronic F-127 (PF-127) and tween 80 as additive of the formulation. All the ingredients were subjected to chemical compatibility studies by Fourier Transform Infra-Red (FTIR) spectroscopy, thermal analysis using Differential Scanning Calorimetry (DSC), whereas X-ray Diffraction (XRD) studies were performed to evaluate the nature of drug in pure form as well as in formulation. The prepared cubosomes were characterized for their size and surface charge, surface morphology, drug release studies and drug permeation studies. Results: FTIR has confirmed the chemical compatibilities of the ingredients, while DSC has exhibited the thermal stabilities of the drug in alone as well as in cubosomes. The XRD has reviled that drug was crystalline, but upon incorporation in cubosmes, the crystallinity has reduced remarkably. The prepared cubosomes were of nanosized (diameter of 227 nm) and cubical in shape. The in vitro drug release and drug permeation studies have showed that concentration of both GMO and PF-127 has effected the release as well as permeation of the drug. However, in 3 hr studies the maximum amount of drug release was ~84% and that of permeation was ~74%. Conclusion: Conclusively, the selected composition of the formulation was suitable enough to prepare the nanosized cubosomes showing suitable entrapment efficiency of the drug. [ABSTRACT FROM AUTHOR]

Bacteria are considered mini chemical factories that help us in providing a wide range of products for various purposes. These days, bacterial cellulose (BC) is getting attention by researchers due to its quality, eco‐friendly nature, and excellent physical‐mechanical qualities. It is being used in the fabrication of nanocomposites. Its nanocomposites can be used in various industries, including medicine, food, leather, textiles, environment, electronics, and cosmetics. This area of research is emerging and still in its infancy stage, as new applications are still coming up. Most of the work on BC has been done during the last two decades and serious inputs are required in this direction in order to make the production process commercially viable and ultimately the application part. Biowastes, such as fruits and vegetables wastes, can be used as a cost‐effective medium to minimize the cost for large‐scale production of BC‐based nanocomposites thus will valorize the biowaste material into a valuable product. Using biowaste as media will also aid in better waste management along with reduction in detrimental environmental effects. This review will help the readers to understand the potential applications of BC and its nanocomposites as well as their vital role in our daily lives. [ABSTRACT FROM AUTHOR]

Purpose: A newly introduced sintering protocol promises to offer higher translucency while not significantly compromising the flexural strength of the material. However, the effect of the novel sintering protocol has not been thoroughly validated. The purpose of this study was to measure and compare the effect of two sintering protocols on the translucency and flexural strength of two multilayered zirconia materials., Materials and Methods: Two types of multilayered zirconia materials (ZirCAD Prime and Prime esthetic) were selected. Presintered disk specimens were obtained from Translucent, Gradient, and Dentin layers (n = 20). The disks were allocated to 2 groups: standard sintering protocol (peak temperature 1500°C) and high translucency sintering protocol (peak temperature 1600°C). After the sintering process, 10 specimens from each group were randomly selected. The optical values (L * , a * , b * ) were measured and used to assess translucency using the relative translucency parameter (RTP 00 ) and translucency differences (ΔRTP 00 ). Then, all 20 specimens were tested for biaxial flexural strength. The outcomes were analyzed. The analysis of variance is used to analyze any significant effects on translucency and flexural strength. Then, any significant difference in the translucency and flexural strength between all pairs of materials was analyzed using Bonferroni-corrected Student's t-test (α = 0.05)., Results: The high translucency sintering protocol significantly decreased biaxial strength in the Prime translucent and dentine layer, Prime esthetic translucent, and gradient layer. RTP 00 was significantly reduced in the Prime gradient and Prime esthetic gradient layer when sintered with a high translucency protocol. The lowest ΔRTP 00 was observed in the Prime dentine layer, while the highest ΔRTP 00 was observed in the Prime esthetic dentin layer., Conclusions: High translucency protocol significantly lowers the biaxial flexural strength of both multilayered materials, but the alteration in translucency is within clinically acceptable thresholds (TAT 00 = 2.62)., (© 2024 The Author(s). Journal of Prosthodontics published by Wiley Periodicals LLC on behalf of American College of Prosthodontists.)

Purpose: This study examined the effect of whitening and abrasive regular dentifrices on the surface characteristics and stain susceptibility of polymer-based CAD-CAM blocks subjected to artificial toothbrushing abrasion (TB)., Materials and Methods: Two resin composite blocks [CeraSmart (CS) and Grandio Blocs (GB)], one polymer-infiltrated ceramic [Vita Enamic (VE)], and one direct resin composite [GrandioSO (RC)] were used to produce 60 specimens. The baseline mass, gloss, roughness, Vickers hardness (Hv), and color were measured after 7 days of water storage. The specimens were then separated into three TB treatment groups (n = 5): water control (C), regular daily dentifrice (R), and whitening dentifrice (W). Measurements were repeated post-TB (20,000 cycles). All specimens were immersed in coffee, and the CIE ΔE 00 was measured after 1, 7, and 14 days. Two-way, one-way ANOVA, and Tukey's post hoc tests were performed to determine any significant differences between the materials and TB groups. To determine the stain resistance, repeated measures of ANOVA, one-way ANOVA, and Tukey's post hoc tests were used (α = 0.05)., Results: The R and W mass changes were minimal (-3.77 to 3.16 g%). W reduced the gloss of all the materials by 12.6%-65%. All materials in W were slightly rougher (Ra, 0.107-0.144 μm) than those in R (Ra, 0.049-0.072 μm). The ΔE 00 ranged from 0.6 to 1.6 in W and 0.4 to 1.4 in R. VE was the hardest material at baseline (Hv = 362), whereas brushing and staining lowered Hv in all TB groups (282.8-300.6). After brushing in W, VE, and RC were more susceptible to coffee stains than were CS and GB., Conclusions: The whitening dentifrice roughened CAD-CAM specimens, reducing gloss, yet lightened some materials. Polymer-infiltrated ceramic and direct resin composite specimens brushed with abrasive regular or whitening dentifrice resulted in more intense staining than the CAD-CAM resin composites., (© 2024 by the American College of Prosthodontists.)

Statement of the Problem: Surface roughness of zirconia is an important parameter that determines the success of zirconia restorations. When zirconia surfaces are left rough, higher susceptibility to hydrothermal aging, plaque accumulation and color changes would occur. Therefore, polish retention of these restorations is considered as a challenge. Purpose: The purpose of this in vitro study was to determine the effect of hydrothermal degradation, pH- cycling, and simulated tooth brushing on surface roughness, topography, and polish retention of an yttrium-stabilized monolithic zirconia. Materials and Method: In this experimental study, 64 specimens of yttria-stabilized tetragonal zirconium oxide (20×4×2mm) were prepared (ZirKonzahn, Steger, Ahrntal). The specimens were wet- polished (standard polishing), and divided into 8 groups (n=8). Four control groups were assessed in non-aged condition while in 4 experimental groups the artificially ageing was done. Different finishing and polishing procedures were performed in 8 groups. The surface roughness values including mean surface roughness (Ra) and mean height of surface roughness (Rz) was measured by a profilometer. The results were analyzed using two-way ANOVA and Tukey’s HSD test (α=0.05). One representative specimen of each group was inspected under a scanning electron microscope (SEM) for assessment of surface topography. Results: The effects of surface treatments on Ra (p<.001) and Rz (p<.001) parameters were significant. Ageing had no significant effect on Ra (p=.086) and Rz (p=.067) values. Maximum Ra and Rz parameters were recorded following grinding (p<.001) and minimum values were recorded after glazing, which were significantly lower than the values in grinding group (p<.001). Polishing and glazing diminished the surface roughness (Ra) of ground zirconia similarly (p=.995). Conclusion: Aging had no significant effect on surface roughness of zirconia, irrespective of surface treatment type. Grinding yielded maximum surface roughness. Intra oral polishing yielded a surface roughness comparable to standard polishing and glazing. [ABSTRACT FROM AUTHOR]

In this work, Ca1−xCuxTiO3 samples (x = 0 (CTO), x = 0.04 (CCTO0.04) and x = 0.08 (CCTO0.08)) were synthesized via the sol–gel method. The influence of A-site copper substitution on the structural, optical, and dielectric properties of Ca1−xCuxTiO3 powders was investigated. X-ray diffraction (XRD) confirmed the formation of a pure perovskite structure. Moreover, Rietveld refinement revealed the crystallization of all samples under the orthorhombic Pbnm structure with the appearance of a minor secondary cubic phase with Cu2+ incorporation in the CaTiO3 host lattice. The vibrational investigation using Micro-Raman (MR) spectroscopy confirmed XRD results. Moreover, MR analysis revealed that A-site copper substitution results in the displacement of Ti atoms which induces distortions in the lattice. Ultraviolet–Visible (UV–Vis) absorption and photoluminescence (PL) measurements revealed the effect of copper-induced structural defects, distortions, and/or strains on the optical properties. Furthermore, the dielectric studies indicated high-temperature stability of the dielectric properties of the samples over a broad temperature range. The photoluminescence and dielectric results suggest that Ca1−xCuxTiO3 powders are promising materials for potential use in several electronic devices such as capacitors and light-emitting devices. [ABSTRACT FROM AUTHOR]

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Purpose: Firing protocols influence the mechanical properties of dental ceramics. This study examined the impact of altering the cooling rate of mono‐ and multilayered 5 mol% yttria‐partially stabilized zirconia (5Y‐PSZ) on their strength. Materials and methods: Ninety specimens (width × length × thickness = 10 × 20 × 2 mm) were prepared using 5Y‐PSZ monolayer (Mo: Cercon‐xt) and 5Y‐PSZ multilayered (Mu: Cercon‐xt ML) blocks. Randomly distributed specimens were sintered at the recommended firing schedule for three different categories of cooling rates (n = 15/group): slow (S: 5°C/min), normal (N: 35°C/min), and fast (F: 70°C/min). A universal testing machine with four‐point bending test was used to measure the flexural strength (σ). The microstructure, fracture characteristics, and chemical composition were evaluated by scanning electron microscope and energy‐dispersive spectroscopy. The monoclinic, tetragonal, and cubic phases were investigated using X‐ray diffraction. Two‐way ANOVA and post hoc Bonferroni comparisons were applied to determine the σ, (p<0.05$p<0.05 $), and Weibull analysis was performed to determine the Weibull modulus (m) and characteristic strength (σ0). Results: The highest σ and σ0 (MPa) were seen for MuN (454.2 ± 62.0, 480.8 ± 62.9) followed by MuS (453.5 ± 52.6, 476.4 ± 54.3) and MoS (451.5 ± 44.5, 471.2 ± 46.6), whereas MuF had the lowest σ and σ0 (379.8 ± 50.2, 401.6 ± 51.3). The σ value of S‐cooling (452.5 ± 47.9) was higher than those for N‐cooling (443.4 ± 61.3) and F‐cooling (382.3 ± 58.0). The m‐value for MoS was the highest (11.4 ± 3.6), whereas that for MoF was the lowest (6.1 ± 1.6). Different cooling rates resulted in a significant difference in σ values (p < 0.05). Conclusions: S‐ and N‐cooling resulted in significantly higher flexural strength than that obtained by F‐cooling. Increasing the cooling rate of 5Y‐PSZ resulted in smaller grain size, less grain boundary integration, and higher t‐ to m‐transformation, leading to lower strength. Therefore, a slow and normal cooling rate was recommended to achieve the optimum strength for 5Y‐PSZ. [ABSTRACT FROM AUTHOR]

Objectives: To assess the probability of survival of crowns made with a 3Y-TZP, a 5Y-TZP, and a lithium disilicate. Materials and methods: CAD-CAM premolar crowns with occlusal thicknesses of 1.0 mm or 1.5 mm and cemented on a metal dye. Step-stress accelerated life testing (SSALT) was performed to access the use level probability Weibull curves and reliability were calculated for the completion of a mission of 100,000 cycles at 300 to 1200 N. Results: All ceramics showed a high probability of survival (87–99%) at 300 N, irrespective of thickness. 3Y-TZP shows no significant decrease in the probability of survival up to 1200 N (83–96%). Lithium disilicate presented lower reliability than zirconia under the 600 N mission. 5Y-TZP showed lower reliability than 3Y-TZP at 1200 N. There was no significant difference in the Weibull modulus (3.23–7.12). 3Y-TZP had the highest characteristic strength (2483–2972 N), followed by 5Y-TZP (1512–1547 N) and lithium disilicate (971–1154 N). Conclusion: Zirconia ceramics have a high probability of survival (up to 900 N-load), while lithium disilicate survives up to 300 N load only, irrespective of the thickness (1.0 mm or 1.5 mm). Clinical relevance: The probability of survival of posterior crowns made with zirconia ceramics resists extreme loads while glass ceramics resist normal chewing loads. In addition, crowns with thinner occlusal face showed sufficient mechanical behavior. [ABSTRACT FROM AUTHOR]

The increase in environmental consciousness has promoted the use of renewable resources. A tremendous spike has been observed in the use of products that decompose into environment-friendly constituents, which leads to the protection of the environment. Such environment-centric thinking has reduced the volume of solid waste generated by consumers every year, together with reuse and recycling. However, the environmentally friendly initiatives and regulations face a setback when the cost is high. Often the quality of such products is compromised in comparison with synthetically derived products for consumer usage. Plastic is a ubiquitous pollutant with potentially harmful effects on living beings. The increasing population and a steady increase in petrochemical plastics' demand hamper global plastic waste management. The use of bioplastics has helped us to overcome these issues. Poly(hydroxybutyrate) (PHB) is commonly known, first synthesized bioplastic, which has strong potential in replacing conventional plastics. This review focuses on the PHB biopolymer's significant properties over plastic, its application in different fields, i.e., medical science, agriculture, construction, packaging, energy, etc. It also covers PHB biosynthesis using different waste products as a substrate to minimize the production process cost, degradation, and different analytical methods to characterize the PHB. Along with these, we have also discussed about the other polysaccharide based biodegradable polymers. [ABSTRACT FROM AUTHOR]

Every year, all over the world, the industry generates huge amounts of residues. Side-streams are most often used as feed, landfilled, incinerated, or discharged into sewage. These disposal methods are far from perfect. Taking into account the composition of the side-streams, it seems that they should be used as raw materials for further processing, in accordance with the zero-waste policy and sustainable development. The article describes the latest achievements in biotechnology in the context of bacterial reprocessing of residues with the simultaneous acquisition of their metabolites. The article focuses on four metabolites — bacterial cellulose, propionic acid, vitamin B12 and PHAs. Taking into account global trends (e.g. food, packaging, medicine), it seems that in the near future there will be a sharp increase in demand for this type of compounds. In order for their production to be profitable and commercialised, cheap methods of its obtaining must be developed. The article, in addition to obtaining these bacterial metabolites from side-streams, also discusses e.g. factors affecting their production, metabolic pathways and potential and current applications. The presented chapters provide a complete overview of the current knowledge on above metabolites, which can be helpful for the academic and scientific communities and the several industries. Key points: • The industry generates millions of tons of organic side-streams each year. • Generated residues burden the natural environment. • A good and cost-effective method of side-streams management seems to be biotechnology – reprocessing with the use of bacteria. • Biotechnological disposal of side-streams gives the opportunity to obtain valuable compounds in cheaper ways: BC, PA, vitmain B12, PHAs. [ABSTRACT FROM AUTHOR]

The oxide glass–ceramics is a promising class of solid state materials because they are using thermally stable and chemically inert glass oxide matrices. Development of such efficient glass matrices suitable for creation of glass–ceramic materials for several purposes is an important practical task. The xLi2O–yV2O5–(100 − x − y)B2O3 undoped glass and 47Li2O–2V2O5–50B2O3–1La0.3Eu0.7VO4 glass samples with crystalline nanoinclusions were synthesized and investigated using XRD, IR and UV–Vis spectroscopy and UV band-to-band excitation of luminescence. The synthesized glass samples are characterized by wide band photoluminescence emission with maximum at 570 nm and intensity increased with increase of Li2O concentration. The excitation spectra consist of three bands with maxima located at 270, 320 and 365 nm. The observed concentration dependencies of spectral distributions in the absorption and excitation spectra are explained by influence of the lithium ions on a ratio between triborate and tetraborate groups in the glass networks. The assumption is made that the observed wide band photoluminescence emission of the glass matrix can appear as a result of recombination processes between the defects in borate networks and the broken vanadate groups. The crystalline component in the doped glass samples is found to not affect the luminescence properties of the glass matrix. Intensity of narrow band photoluminescence emission of the crystalline component is up to 10 times more intense than that of the glass matrix wide band emission. The synthesized type of the glass matrices has promising characteristics for the use of developed materials in lighting devices, as it allows improving the spectral distribution of light emission towards the white light. [ABSTRACT FROM AUTHOR]

Neodymium doped Bismuth Ferrite (Nd-BFO) samples, synthesized using solid-state reaction route are subjected to various structural and dielectric characterization to investigate the influence of Nd3+ ions in modifying bismuth ferrite multiferroic properties. Structural characterizations including XRD, FESEM, FTIR, and Raman characterization have shown that higher amount of dopant concentration has caused disruption in the structural ordering. Dielectric studies such as dielectric constant, loss, measured using an LCR meter with respect to the temperature and frequency variations are analyzed in this paper. Further electrical characterization such as impedance analysis is also presented. All these results broadly indicate the tunable electrical nature of these samples at different temperatures and frequencies, with doping, which is a correlation to their structural and morphological ordering and low concentration doped Nd-BFOs only possess the potential for applications. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) techniques such as laser powder bed fusion (LPBF) and directed energy deposition (DED) are viable methods to produce large-size bulk metallic Glass (BMG) components. Even though BMGs with low glass forming abilities (GFA) can potentially be manufactured via AM, the resultant build undergoes partial devitrification, structural relaxation, cracking, or picks up oxygen (O). O pick-up is a serious issue for AM fabricated BMGs as it causes embrittlement and affects its potential use as a structural material. Here, a detailed review of the O pick-up in BMGs during AM fabrication is provided. The effect of O on the propensity of crystal nuclei formation and the glass forming ability of BMGs is critically discussed. Thereafter, the effect of on the mechanical properties of BMGs, and how it affects its structural performance are reviewed. Above a certain threshold, which could be composition-specific, O improves the strength of the BMG but diminishes its fracture, fatigue, and plasticity. These discussions will lead to the formulation of some future directions of research in AM fabrication of BMGs that have both scientific and technological relevance. [ABSTRACT FROM AUTHOR]

We investigate the direct and indirect effects of silica nanoparticles, NP, on the molecular mobility and crystallization of a series of polymer nanocomposites, PNCs, based on polylactide, PLA. To that aim, a sum of complementary techniques was employed, namely infrared spectroscopy, calorimetry, dielectric spectroscopy, X-ray diffraction, polarized and electron microscopy. The introduction of NPs was found to result in formation of interfacial interactions, an in general moderate elevation of the glass transition temperature and a suppression of the chains fragility/cooperativity. Regarding crystallinity, neither the unfilled PLA nor the PNCs were found to crystallize during cooling from the melt state, whereas all samples crystallize upon heating (cold crystallization), suggesting that the initially slow crystallization and poor nucleation of the used PLA was not improved. The degree of crystallinity upon the addition of NP is also suppressed. Surprisingly, severely more active nuclei were recorded in the PNCs. This is interpreted in terms of the indirect effect of slowing down of the chains' diffusion related to the NP-polymer interaction. This results in slower crystals' growing around more PLA-nuclei in PNCs as compared to the unfilled matrix, within which the antagonistic crystal growing is faster and dominant around less nuclei. This is also manifested by altered crystals structuring in terms of crystals with smaller size and lower density. Regarding local dynamics, the local β relaxation screening the dipolar motions arising from the crankshaft motion of the backbone ‒C=O was recorded to follow, on the one hand, the formation of interfacial interactions via the suppression of its strength and, on the other hand, to be sensitive to large scale phase changes (glassy to rubbery). Finally, an additional relaxation process was recorded in the highly loaded PNCs and assigned to modified PLA mobility. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the chemical composition, flexural strength, and Weibull characteristics of milled and lithography‐based additively manufactured (AM) zirconia. Materials and methods: A virtual design of a bar (25×4×2 mm) was completed using a software program. The standard tessellation language file was used to manufacture all the specimens: 3Y‐TZP zirconia (Priti multidisc ZrO2 monochrome) milled (M group) and 3Y‐TZP zirconia (LithaCon 3Y 210) lithography‐based AM (CeraFab System S65 Medical) (AM group) bar specimens (n = 20). The chemical composition of the specimens was determined by using energy dispersive X‐ray (EDAX) elemental analysis in a scanning electron microscope. Flexural strength was measured in all specimens using 3‐point bend test according to ISO/CD 6872.2 with a universal testing machine (Instron Model 8501). Two‐parameter Weibull distribution values were calculated. The Shapiro‐Wilk test revealed that the data were normally distributed (p < 0.05). Flexural strength values were analyzed using independent Student's t‐test (α = 0.05). Results: There were no major chemical composition differences observed between M and AM groups. The AM specimens (1518.9 ± 253.9 MPa) exhibited a significantly higher flexural strength mean value compared to the milled (980.5 ± 130.3 MPa) specimens (DF = 13, T‐value = –5.97, p < 0.001). The Weibull distribution presented the highest shape for M specimens (11.49) compared to those of AM specimens (6.95). Conclusions: There was no significant difference in the chemical composition of milled and AM zirconia material tested. AM zirconia tested exhibited significantly higher flexural strength compared with the milled zirconia evaluated. [ABSTRACT FROM AUTHOR]

Cellulose, the most abundant polysaccharide on earth, can be obtained from various sources including the cell wall of plants and woods, bacteria, algae, and tunicates. However, the cellulose obtained from bacteria known as bacterial cellulose or bacterial nanocellulose (BC) has gained major popularity due to its simple production process, non–toxicity, high purity, and biocompatibility. Furthermore, the BC holds distinct properties like higher crystallinity, larger surface area, high porosity, great water holding capacity, and enhanced tensile strength. These unique features of BC further widen its application in several areas including drug delivery, tissue engineering, wound dressing, etc. The present review summarizes the recent developments in BC production and its biomedical applications. Firstly, the microorganisms involved, various medium compositions used and the methods adopted for BC production are discussed, and then reactors used for industrial production of BC are introduced. Subsequently, the applications of BC in tissue engineering, drug delivery system, and pharmaceutical & medical sectors are discussed in detail. Finally, the future perspective of BC in biomedical applications is discussed in brief. [ABSTRACT FROM AUTHOR]

Background: Mechanical surface treatments can deteriorate the mechanical properties of zirconia. This study evaluated and compared the biaxial flexural strength, fracture toughness, and fatigue resistance of high translucency (HT) to low translucency (LT) zirconia after various mechanical surface treatments. Methods: Four hundred eighty zirconia discs were prepared by milling and sintering two HT (Katana and BruxZir) and LT (Cercon and Lava) zirconia blocks at targeted dimensions of 12 mm diameter × 1.2 mm thickness. Sintered zirconia discs received one of the following surface treatments: low-pressure airborne particle abrasion (APA) using 50 µm alumina particles, grinding using 400 grit silicon carbide paper, while as-sintered specimens served as control. Internal structure and surface roughness were evaluated by scanning electron microscope (SEM) and a non-contact laser profilometer, respectively. Half of the discs were tested for initial biaxial flexural strength, while the rest was subjected to 106 cyclic fatigue loadings, followed by measuring the residual biaxial flexural strength. Fractured surfaces were examined for critical size defects (c) using SEM to calculate the fracture toughness (KIC). The effect of surface treatments, zirconia type, and cyclic fatigue on the biaxial flexural strength was statistically analyzed using three-way analysis of variance (ANOVA) and Tukey HSD post hoc tests (α = 0.05). Weibull analysis was done to evaluate the reliability of the flexural strength for different materials. Results: The initial biaxial flexural strength of LT zirconia was significantly higher (p < 0.001) than that of HT zirconia in all groups. While low APA significantly increased the biaxial flexural strength of LT zirconia, no significant change was observed for HT zirconia except for Katana. Surface grinding and cyclic fatigue significantly reduced the flexural strength of all groups. High translucency zirconia reported higher fracture toughness, yet with lower Weibull moduli, compared to LT zirconia. Conclusion: LT zirconia has higher biaxial flexural strength, yet with lower fracture toughness and fatigue resistance, compared to HT zirconia. Low-pressure APA has significantly increased the biaxial flexural strength in all zirconia groups except BruxZir. Grinding was deteriorating to biaxial flexural strength and fracture toughness in all zirconia types. Cyclic fatigue has significantly decreased the biaxial flexural strength and reliability of HT and LT zirconia. [ABSTRACT FROM AUTHOR]

China is the third largest sugar producer in the world. However, the sugar industry is challenged by high production costs (attributed to the high cane supply price), which lead to continuous financial deficits for sugar companies. Currently, sugarcane products are primarily composed of white sugar and non-centrifugal sugar (NCS); the utilization of sugarcane by-products (i.e. bagasse, filter mud, and molasses) has also been partially industrialized. However, these strategies are far from adequate to address the challenge. China has successfully developed an innovative sugar manufacturing process using nano-ceramic membrane technology to overcome this predicament. In addition, concepts of high-value diversification of sugarcane products and value-added utilization of industrial by-products have been proposed. A series of sugarcane-based products, e.g. NCS produced by nano-ceramic membrane technology (MNCS), sugarcane-based beverages, plant water, and cultivation substrates, have been developed to improve the overall return of sugar enterprises. Thus, this paper mainly summarizes the diversification of sugarcane products and their development opportunities in China. [ABSTRACT FROM AUTHOR]

Glass-forming alloys are very sensitive to oxygen contaminations. Here, the oxygen-scavenging effect of five rare-earth elements (REEs) was studied when added to the Zr50Cu40Al10 alloy, synthesized from commercially available zirconium. The effects of precise REEs additions (Y, Sc, Lu, Gd, Nd) with respect to the measured oxygen content, based on the stoichiometric relationship in the M2O3 oxide, are reported. Additionally, the influence of double and triple REE-to-oxygen ratios on the critical diameter (Dc) and other glass-forming ability (GFA) indicators were investigated. To evaluate the GFA and phase transformations during heating, differential thermal analysis was performed along with neutron diffraction. The combination of these two techniques allowed to identify crystallization products and distinguish the differences in phase transformations of low and high-oxygen-content alloys. Microstructural analysis was carried out by means of electron microscopy (SEM, STEM), supported by X-ray diffraction. The best oxygen scavengers were found to be rare earths that form cubic sesquioxides, i.e., Y, Sc, and Lu, allowing to increase Dc in the high-oxygen Zr50Cu40Al10 alloy from 2.5 mm up to 8 mm (double-stoichiometric concentration of Y-to-oxygen). Our results indicate that low-purity alloys can be easily vitrified, highlighting their potential for wide commercialization. [ABSTRACT FROM AUTHOR]