Excessive ultraviolet B ray (UVB) exposure to sunlight results in skin photoageing. Our previous research showed that a Q‐switched 1064 nm Nd: YAG laser can alleviate skin barrier damage through ...miR‐24‐3p. However, the role of autophagy in the laser treatment of skin photoageing is still unclear. This study aims to investigate whether autophagy is involved in the mechanism of Q‐switched 1064 nm Nd: YAG in the treatment of skin ageing. In vitro, primary human dermal fibroblast (HDF) cells were irradiated with different doses of UVB to establish a cell model of skin photoageing. In vivo, SKH‐1 hairless mice were irradiated with UVB to establish a skin photoageing mouse model and irradiated with laser. The oxidative stress and autophagy levels were detected by western blot, immunofluorescence and flow cytometer. String was used to predict the interaction protein of TGF‐β1, and CO‐IP and GST‐pull down were used to detect the binding relationship between TGFβ1 and ITGB1. In vitro, UVB irradiation reduced HDF cell viability, arrested cell cycle, induced cell senescence and oxidative stress compared with the control group. Laser treatment reversed cell viability, senescence and oxidative stress induced by UVB irradiation and activated autophagy. Autophagy agonists or inhibitors can enhance or attenuate the changes induced by laser treatment, respectively. In vivo, UVB irradiation caused hyperkeratosis, dermis destruction, collagen fibres reduction, increased cellular senescence and activation of oxidative stress in hairless mice. Laser treatment thinned the stratum corneum of skin tissue, increased collagen synthesis and autophagy in the dermis, and decreased the level of oxidative stress. Autophagy agonist rapamycin and autophagy inhibitor 3‐methyladenine (3‐MA) can enhance or attenuate the effects of laser treatment on the skin, respectively. Also, we identified a direct interaction between TGFB1 and ITGB1 and participated in laser irradiation‐activated autophagy, thereby inhibiting UVB‐mediated oxidative stress further reducing skin ageing. Q‐switched 1064 nm Nd: YAG laser treatment inhibited UVB‐induced oxidative stress and restored skin photoageing by activating autophagy, and TGFβ1 and ITGB1 directly incorporated and participated in this process.
•Experimental studies based on Nd-YAG LBC have been reviewed.•Four different ways of LBC and different aspects of LBC have been discussed.•Process behaviour with conventional and unconventional sheet ...materials is explained.•Parametric influences on laser cutting performance index have been discussed.•Applications of experimental modeling and optimization approaches during LBC process have been analyzed.
Cutting of sheet material is considered as an important process due to its relevance among products of everyday life such asaircrafts, ships, cars, furniture etc. Among various sheet cutting processes (ASCPs), laser beam cutting is one of the most capable ASCP to create complex geometries with stringent design requirements in difficult-to-cut sheet materials. Based on the recent research work in the area of sheet cutting, it is found that the Nd-YAG laser is used for cutting of sheet material in general and reflective sheet material in particular. This paper reviews the experimental analysis of Nd-YAG laser cutting process, carried out to study the influence of laser cutting parameters on the process performance index. The significance of experimental modeling and different optimization approaches employed by various researchers has also been discussed in this study.
A large amount of Li‐containing ceramic breeder pebbles is packed in the solid breeding blanket of a nuclear fusion reactor. Several pebble fabrication technologies have been proposed in previous ...studies, including wet process, emulsion method, extrusion spheronization, additive manufacturing, and melt process. However, a simple, energy‐effective, and scalable fabrication technology remains to be developed for the automated mass production and reprocessing of used radioactive pebbles post‐operation. Selective laser melting potentially enables the quick and automated fabrication of breeder pebbles. Herein, we employ a high‐power density pulse laser to produce ceramic breeder pebbles. A pulsed YAG laser was irradiated over a lithium metatitanate (Li2TiO3) powder bed in air, and the corresponding temperature was monitored using fiber‐type infrared pyrometers. Spherical Li2TiO3 pebbles were successfully fabricated in a single step with an average diameter of 0.78 ± 0.13 μm and the sintering density of 87.4% ± 5.6% (input power: 7.9 J/pulse). The irradiated Li2TiO3 powder melted and turned spherical under surface tension and rapidly solidified, resulting in uniaxial fine grains and a decrease in the degree of long‐range cation ordering.
One‐step fabrication of Li2TiO3 pebble using pulsed YAG laser
Macular amyloidosis (MA) is one of the most common types of primary localized cutaneous amyloidosis (PLCA), distributed predominantly over the trunk and extremities. Due to the vast therapeutic ...options, this study aims to compare the effectiveness of Q-switched Nd: YAG laser 1064 nm and Er: YAG laser 2940 nm in treating MA. This clinical trial was performed in 2020–2021 on 33 women with MA. In each patient, the lesion was randomly divided into two areas, A and B. Area A underwent four treatment sessions with 4-week intervals of Q-switched Nd: YAG laser 1064 nm. Area B underwent four treatment sessions with an Er: YAG laser 2940 nm at 4-week intervals. Degree of basal pigmentation and degree of pigmentation after treatment, pruritus intensity, before and after the treatment, and patient and physicians’ satisfaction were measured and compared. The pruritus in patients improved significantly after the study (
P
< 0.001), but no significant differences could be observed between the two groups regarding the improvements (
P
> 0.05). We also found no significant differences between the two groups of patients regarding patient and physicians’ satisfaction rates (
P
> 0.05). The use of both Q-switched Nd: YAG laser and Er: YAG laser resulted in improvements in terms of pruritus, patient and physicians’ satisfaction, and total improvement in pigmentation of the lesions.
Every lobectomy requires the transection of the interlobar fissure. Resection surfaces must be airtight in order to avoid leakage and infection. Using an ex vivo model based on porcine lung, we ...compared three techniques with respect to initial airtightness at different inspiratory pressures.
In the first technique (group 1), we transected the interlobar fissure with a monopolar cutter and overstitched the edges of the resection area with a monofilament thread. In the second technique (group 2), the interlobar fissure was cut with a stapling device. In the third technique (group 3), the interlobar fissure was cut using a laser fibre connected to an Nd: YAG laser. The resection areas were not overstitched; 15 transections were performed in each group.
In group 1, three parenchymatous bridges leaked starting at a pressure of 25 mbar. In the other two groups, all preparations were airtight at this pressure. If the ventilation pressure was increased up to 40 mbar, all seams in group 1 were leaky at a pressure of 35 mbar. Four staple seams were airtight at a pressure of 40 mbar. In group 3, 11 preparations (73.3 %) were airtight up to a pressure of 40 mbar.
Based on our results, the use of an Nd: YAG laser is suitable for the transection of the interlobar fissure. In effect, this technique compares well with the other techniques examined.
•Titanium and its alloys are destroyed by the conventional welding process.•Control of welding parameters and heat input can prevent destruction of Ti alloys.•Pulsed laser welding is precise and ...enables rapid processing with less heat input.•However, rapid cooling rates increase the cracking risk of pulsed laser welding.•Carefully selected laser welding parameters and filler material can prevent cracks.
The excellent properties of titanium and titanium alloys, including corrosion resistance, high strength to weight ratio and high operating temperature, have led to their successful application in various fields. However, titanium and its alloys are destroyed by the conventional welding process if welding parameters are not controlled. Laser welding is one of the most reliable methods for use with titanium alloys because of its precision and rapid processing capability. In addition, it enables control of the welding parameters and their effects. In this study, Ti-6Al-4V alloy sheets were welded by Nd: YAG pulsed laser and the potential crack risk on the weld joints was investigated. The optimum results obtained in 3.9kW peak power, better ductility was obtained from the Grade 1 titanium alloy filling material.
Evaluation of the impact of the latest root canal disinfectant, that is carbon quantum dots (CQDs), synchronized microbubble-photodynamic activation (SYMPA), and Nd: YAG laser along with ...ethylenediaminetetraacetic acid (EDTA) as a final irrigant on the Marten hardness (MH), smear layer (SL) removal, and extrusion bond strength (EBS) of zirconia post to the canal dentin. Eighty intact single-rooted premolars were obtained and disinfected using 0.5% chloramine-T solution. Root canal preparation was performed using ProTaper files followed by obturation. The post space was prepared for prefabricated zirconia post and all the teeth were randomly divided into four groups based on the disinfection used (n = 20 each) Group 1: 5.25% NaOCl + 17% EDTA (Control), Group 2: Nd: YAG laser + 17% EDTA, Group 3: SYMPA + 17% EDTA, and Group 4: CQDs + 17% EDTA. MH, SL removal, and EBS of zirconia post-bonded to root dentin were performed using a microhardness tester, scanning electron microscope (SEM), and universal testing machine, respectively. Both intragroup and intergroup comparisons were performed using one-way analysis of variance (ANOVA) and posthoc-Tukey test for significant difference (p < .05). Group 2 samples (Nd: YAG laser + 17% EDTA) (0.24 ± 0.06 GPa) exhibited highest values of MH. Samples in group 3 (SYMPA + 17% EDTA) treated teeth unveiled the lowest MH scores (0.13 ± 0.02 GPa). Moreover, the coronal third of Group 3 specimens (SYMPA and 17% EDTA) (1.54 ± 0.31) eliminated SL from the canal with the greatest efficacy as well as presented the highest EBS (10.13 ± 0.69 MPa). However, the apical third of Group 1 samples (5.25% NaOCl + 17% EDTA) (2.95 ± 0.33) exhibited the least efficient elimination of SL from the radicular dentin as well as the lowest bond strength (5.11 ± 0.19 MPa) of zirconia post to the dentin. The SYMPA technique with 17% EDTA proved highly effective in removing the SL from canal dentin and enhancing the EBS of zirconia posts. The least preferable method for SL removal and MH improvement was found to be 5.25% NaOCl + 17% EDTA. CQDs and Nd: YAG laser demonstrated satisfactory smear layer removal properties from the canal, along with achieving appropriate bond strength of zirconia posts. RESEARCH HIGHLIGHTS: Nd: YAG laser and 17% EDTA as canal disinfectant exhibited the highest values of MH. Specimens irrigated with SYMPA and 17% EDTA eliminated SL from the canal with the greatest efficacy. The coronal third of Group 3 (SYMPA + 17% EDTA) samples unveiled the highest zirconia post-bond integrity score to the canal dentin. Cohesive failure was a dominant failure type among different experimental groups.
•Develop a numerical expression to predict the tensile strength of welded joint.•Fine dendritic grains and a narrow HAZ is witnessed in optimum condition.•Tensile strength of the dissimilar joints is ...reported.
In this study, an empirical relationship is developed to predict the tensile strength of pulsed Nd: YAG laser welded Hastelloy C-276–Monel 400 alloy sheets by optimizing the process parameters viz., welding speed, pulse energy and pulse duration. Experiments were conducted based on a three factor, three level, central composite face centered design with full desirability. Analysis of Variance (ANOVA) results indicate that the welding speed holds the greatest influence on tensile strength, followed by pulse energy and pulse duration. Microstructural studies of the optimized condition reveal full penetration weld with finer dendritic grains and a narrow heat affected zone (HAZ). Tensile fracture surface of the optimized weld exhibits a ductile mode of fracture with high tensile strength. XRD analysis of weld zone exposed the formation of various Chromium-rich carbide and Nickel-rich oxides precipitates.
•To fabricate microchannels on transparent material.•PMMA micro-channelling in an open-air environment using a Nd: YAG laser.•Predictions and empirical outcomes are closely aligned, demonstrating the ...superiority of the model.
Among the fastest growing basic materials, polymers have good strength-to-weight ratios, easy to shape, relatively economical, and recyclable which enabled it to become substitutes for metals and alloys in the fields of medical, automobile, aerospace, electronics, thermal and chemical engineering. But a thick transparent PMMA plate creates deep sub-surface cracks due to the burning and charring of polymeric chains, making the operation with Nd: YAG laser radiation extremely difficult. In the current research, a 75 W nanosecond pulsed Nd: YAG laser system is applied to make micro-channel with adequate depth on a thick transparent PMMA plate by using transmission cutting technique. The input process factors considered are pulse width, laser power, cutting speed, and pulse frequency in order to examine the quality characteristics, the depth of cut and heat affected zone (HAZ) in and around the formed micro-channel. To design the experiment of laser transmission channelling of thick PMMA plate of 11 mm, a central composite design (CCD) methodology is used. Due to open-air laser processing, undesirable laser processing effects have been minimised, resulting in a finer and cleaner micro-channel structure with adequate depth of cut, kerf width and minimal Heat Affected Zone (HAZ) width with laser power of around 9 W, pulse frequency of around 33 kHz and cutting speed of 2 mm/sec.
