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2022 ◽  
Vol 12 (3) ◽  
pp. 489-493
Author(s):  
Yung-Sheng Yen ◽  
Han-Yi Cheng ◽  
Hung-Ta Lin

The aim of the present study was to investigate the effect of nano-etched surface and diamond-like carbon (DLC) surface acupuncture needles on human pain perception, by finite element method (FEM). Skin models were reconstructed by 3D computer programs. The stress is an important role in acupuncture needle applications for clinical treatment. Many studies have investigated finite element researches for acupuncture; however, few have evaluated a model for acupuncture with and without\ modified surface. The results revealed that abnormal focusing stress was found when acupuncture with nano-etched surface. Moreover, the unbalance stress was found on the top of the skin model in the nano-etched group, the highest stress also appeared in the top region. Acupuncture with nano-etched surface would be an effective means for stimulating skin. These results indicate subtle but significant effects of acupuncture stimulation with nano-etched surface needles, compared to acupuncture with untreated needles in healthy participants.


Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4268
Author(s):  
Nai-Chia Teng ◽  
Aditi Pandey ◽  
Wei-Hsin Hsu ◽  
Ching-Shuan Huang ◽  
Wei-Fang Lee ◽  
...  

Many revolutionary approaches are on the way pertaining to the high occurrence of tooth decay, which is an enduring challenge in the field of preventive dentistry. However, an ideal dental care material has yet to be fully developed. With this aim, this research reports a dramatic enhancement in the rehardening potential of surface-etched enamels through a plausible synergistic effect of the novel combination of γ-polyglutamic acid (γ-PGA) and nano-hydroxyapatite (nano-HAp) paste, within the limitations of the study. The percentage of recovery of the surface microhardness (SMHR%) and the surface parameters for 9 wt% γ-PGA/nano-HAp paste on acid-etched enamel were investigated with a Vickers microhardness tester and an atomic force microscope, respectively. This in vitro study demonstrates that γ-PGA/nano-HAp treatment could increase the SMHR% of etched enamel to 39.59 ± 6.69% in 30 min. To test the hypothesis of the rehardening mechanism and the preventive effect of the γ-PGA/nano-HAp paste, the surface parameters of mean peak spacing (Rsm) and mean arithmetic surface roughness (Ra) were both measured and compared to the specimens subjected to demineralization and/or remineralization. After the treatment of γ-PGA/nano-HAp on the etched surface, the reduction in Rsm from 999 ± 120 nm to 700 ± 80 nm suggests the possible mechanism of void-filling within a short treatment time of 10 min. Furthermore, ΔRa-I, the roughness change due to etching before remineralization, was 23.15 ± 3.23 nm, while ΔRa-II, the roughness change after remineralization, was 11.99 ± 3.90 nm. This statistically significant reduction in roughness change (p < 0.05) implies a protective effect against the demineralization process. The as-developed novel γ-PGA/nano-HAp paste possesses a high efficacy towards tooth microhardness rehardening, and a protective effect against acid etching.


Author(s):  
Ahmet Toprak ◽  
Doğan Yılmaz ◽  
Ekmel Ozbay

Abstract In this paper, an alternative selective dry etching of p-GaN over InAlN was studied as a function of the ICP source powers, RF chuck powers and process pressure by using inductively coupled plasma reactive ion etching (ICP RIE) system. A recipe using only BCI3-based plasma with a resulting selectivity 13.5 for p-GaN in respect to InAlN was demonstrated. Surface roughness measurements depending on the etching time was performed by atomic force microscope (AFM) measurement and showed that a smooth etched surface with the root-mean-square roughness of 0.45 nm for p-GaN and 0.37 nm for InAlN were achieved. Normally-off p-GaN/InAlN HEMT device was fabricated and tested by using the BCI3-based plasma we developed.


Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1452
Author(s):  
Potejana Potejanasak

In this study, an efficient nanofabrication process of metal microdisk arrays using direct imprinting was developed. This process was comprised of three steps; sputter etching on the quartz glass substrate, gold thin film deposition on an etched surface of a substrate, and transfer imprinting using a polyethylene terephthalate (PET) film mold on the Au thin film. A new idea to utilize a PET film mold for disk patterning by the nano transfer imprinting was examined. The PET film mold was prepared by thermally embossing the pillar pattern of a master mold on the PET film. The master mold was prepared from a silicon wafer. The PET film mold was used for transfer imprinting on a metal film deposited on a quartz substrate. The experimental results revealed that the PET film mold can effectively form gold micro-disk arrays on the Au film despite the PET film mold being softer than the Au film. This method can control the distribution and orientation of the nano-arrays on the disk. The plasmonic properties of the gold micro-disk arrays are studied and the absorbance spectrum exhibit depends on the distribution and orientation of gold micro-disk patterns. The nano-transfer imprinting technique is useful for fabricating metallic microdisk arrays on substrate as a plasmonic device.


2021 ◽  
Author(s):  
Carolin Aslanian ◽  
Raymond Jonckheere ◽  
Bastian Wauschkuhn ◽  
Lothar Ratschbacher

Abstract. The tools for interpreting fission-track data are evolving apace but, even so, the outcomes cannot be better than the data. Recent studies that have again taken up the issues of etching and observation have shown that both have an effect on confined-track length measurements. We report experiments concerning the effects of grain orientation, polishing, etching and observation on fission-track counts in apatite. The results cannot be generalized to circumstances other than those of the experiments, and thus do not solve the problems of track counting. Our findings nevertheless throw light on the factors affecting the track counts, and thence the sample ages, whilst raising the question: what counts as an etched surface track? This is pertinent to manual and automatic track counts and to designing training strategies for neural networks. We cannot be confident that counting prism faces and using the ζ-calibration for age calculation are adequate for dealing with all etching- and counting-related factors across all samples. Prism faces are not unproblematic for counting and other surface orientations are not per se useless. Our results suggest that a reinvestigation of the etching properties of different apatite faces could increase the range useful for dating, and so lift a severe restriction for provenance studies.


Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 958
Author(s):  
Seungryul Yoo ◽  
Dong Chan Seok ◽  
Kang Il Lee ◽  
Yong Ho Jung ◽  
Yong Sup Choi

SiC wafers were etched using a filament plasma of He:NF3:O2 (helium:nitrogen trifluoride:oxygen) mixed gas at atmospheric pressure. When 0.5–2 sccm of NF3 was mixed to 2 slm of He filament plasma, the etch depth and etch rate increased, but there was little change in the etch width as the NF3 mixing amount increased. The increment of the NF3 mixing also suppressed the surface roughening of plasma etching. The addition of O2 to the He-NF3 filament plasma slightly increased the SiC wafer etch rate. When the NF3 mixing amount was 2 sccm, the roughness of the etched surface increased sharply by O2 addition. On the contrary, the NF3 mixing amount was 1 sccm; the addition of O2 reduced the roughness more than that of the pristine. The roughness of the pristine SiC wafer specimens is in the range of Ra 0.7–0.8 nm. After 30 min of etching on a 6 mm by 6 mm square area, the roughness of the etched surface reduced to Ra 0.587 nm, while the etch rate was 2.74 μm/h with a He:NF3:O2 of 2:1:3 (slm:sccm:sccm) filament plasma and 3 mm/s speed of raster scan etch of the optimized roughening suppression etching recipe.


2021 ◽  
Vol 22 (16) ◽  
pp. 8507
Author(s):  
Eugenio Velasco-Ortega ◽  
Iván Ortiz-Garcia ◽  
Alvaro Jiménez-Guerra ◽  
Enrique Núñez-Márquez ◽  
Jesús Moreno-Muñoz ◽  
...  

Titanium surface is an important factor in achieving osseointegration during the early wound healing of dental implants in alveolar bone. The purpose of this study was to evaluate sandblasted-etched surface implants to investigate the osseointegration. In the present study, we used two different types of sandblasted-etched surface implants, an SLA™ surface and a Nanoblast Plus™ surface. Roughness and chemical composition were evaluated by a white light interferometer microscope and X-ray photoelectron spectroscopy, respectively. The SLA™ surface exhibited the higher values (Ra 3.05 μm) of rugosity compared to the Nanoblast Plus™ surface (Ra 1.78 μm). Both types of implants were inserted in the femoral condyles of ten New Zealand white rabbits. After 12 weeks, histological and histomorphometric analysis was performed. All the implants were osseointegrated and no signs of infection were observed. Histomorphometric analysis revealed that the bone–implant contact % (BIC) ratio was similar around the SLA™ implants (63.74 ± 13.61) than around the Nanoblast Plus™ implants (62.83 ± 9.91). Both implant surfaces demonstrated a favorable bone response, confirming the relevance of the sandblasted-etched surface on implant osseointegration.


2021 ◽  
Vol 15 (6) ◽  
pp. 1765-1772
Author(s):  
Shiva Alavi ◽  
Fateme Gharibpour

background: the bond strength of bracket to the tooth substrate is a critical matter. The different surface treatments are introduced to achieve an appropriate bond strength. We aimed to investigate the shear bond strength(SBS) of metal brackets to amalgam surfaces with universal adhesive and compared the results with the enamel group. Material and methods: in this in-vitro study, eighty specimens of amalgam in four groups and sixty specimens of the enamel in three groups were prepared. In amalgam groups, the control group was sandblasted and treated with transbond Xt whilst the other three groups prepared in the following order, group 2 sandblasted and treated with All Bond Universal(ABU), group 3 using diamond bur and ABU, and group 4 using self-etch mode of ABU. In enamel groups, control group was acid-etched and using transbond XT as a primer; in other two groups, the ABU was used as a primer in etched and self-etched mode. The specimens thermocycled and prepared for the SBS test. SEM analysis and ARI index were performed. pvalue≤ was considered significantly. Results: SBS of enamel was significantly higher than amalgam. Within enamel groups, etched with ABU showed the highest SBS. In amalgam group, the highest SBS was related to surface treated with ABU only, and the lowest SBS was related to diamond bur group. Conclusion: The etched surface of enamel showed the appropriate bond strength to bracket, and in the amalgam group, using mechanical preparation can decrease the oxide layer and compromise amalgam SBS. Keywords: Dental amalgam, Enamel, shear strength, Adhesive


Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 777
Author(s):  
Nansi López-Valverde ◽  
Antonio López-Valverde ◽  
Juan Manuel Aragoneses ◽  
Francisco Martínez-Martínez ◽  
María C. González-Escudero ◽  
...  

Peri-implant bone density plays an important role in the osseointegration of dental implants. The aim of the study was to evaluate via micro-CT, in Hounsfield units, the bone density around dental implants coated with chitosan and melatonin and to compare it with the bone density around implants with a conventional etched surface after 12 weeks of immediate post-extraction placement in the jaws of Beagle dogs. Six dogs were used, and 48 implants were randomly placed: three groups—melatonin, chitosan, and control. Seven 10 mm × 10 mm regions of interest were defined in each implant (2 in the crestal zone, 4 in the medial zone, and 1 in the apical zone). A total of 336 sites were studied with the AMIDE tool, using the Norton and Gamble classification to assess bone density. The effect on bone density of surface coating variables (chitosan, melatonin, and control) at the crestal, medial, and apical sites and the implant positions (P2, P3, P4, and M1) was analyzed at bivariate and multivariate levels (linear regression). Adjusted effects on bone density did not indicate statistical significance for surface coatings (p = 0.653) but did for different levels of ROIs (p < 0.001) and for positions of the implants (p = 0.032). Micro-CT, with appropriate software, proved to be a powerful tool for measuring osseointegration.


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