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Copyright of Journal of Donghua University (English Edition) is the property of Journal of Donghua University Editorial Board 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.)

To investigate the mechanism underlying high acid resistance of enamel after erbium laser etching. Forty-five premolars were collected and assigned to three groups. A 4×4×1 mm enamel sample was prepared, the left side was the control side, the right side was the treated side, which was treated with different surface treatments, including 35% phosphoric acid etching, Er:YAG laser etching, and Er,Cr:YSGG laser etching. The hydroxyapatite crystal size on the enamel surface of the samples was observed. The contents of Ca, P, O, F, Cl, C, Mg were detected. The crystallinity of the hydroxyapatite crystal was analyzed. After erbium laser etching, the enamel surface had high hydroxyapatite crystal size, beneficial content of chemical elements and crystallinity. The morphological and composition changes of crystals in the enamel surface after erbium laser etching may be one of the crucial mechanisms underlying the enhancement of acid resistance of enamel after erbium laser etching. [ABSTRACT FROM AUTHOR]

Polyetheretherketone (PEEK) is a highly sought-after thermoplastic due to its exceptional mechanical properties and biocompatibility. However, bonding PEEK to indirect composite resin (ICR) or denture-based resin (DBR) can be challenging. Laser engraving technology has shown potential to improve bonding for other materials; thus, this study aims to evaluate its effectiveness for PEEK. The experiment involved preparing ingot-shaped PEEK samples, which were then categorized into four groups based on the treatment method employed: without treatment, air abrasion, sulfuric acid etching, and laser engraving (LS). Subsequently, the samples were bonded to ICR or DBR, and their shear bond strength (SBS) was tested with or without thermocycling using a universal testing machine. Furthermore, the failure mode was observed, with statistical analyses conducted to compare the results. The grid-like microslit structure of LS group displayed the highest SBS for bonding PEEK to ICR or DBR (P < 0.05). During the bonding of PEEK to ICR, resin residue and penetration into the microslits were frequently observed in the LS group, indicating cohesive failure. However, when PEEK was bonded to DBR, mixture failure was frequently observed without thermocycling. After thermocycling, only the LS group showed cohesive failure, while the majority of specimens exhibited mixture failure. Laser engraving significantly improves the SBS between PEEK and both ICR and DBR. Furthermore, it was observed that resin had penetrated the microslits, indicating that laser engraving has great potential as a surface treatment method. [ABSTRACT FROM AUTHOR]

• Novel recovery technique is as effective as Fry's reagent for removed stamped marks. • Two recovery methods failed to recover laser engraved marks once obliterated. • Inability to recover laser engraved marks from steel plates or firearms. The International Tracing Instrument (ITI) is a document adopted by United Nations Member States in 2005, which outlines challenges faced in the tracing of illicit weapons and offers suggestions to increase the success of tracing operations. A key provision of the ITI states that serial numbers must be recoverable if obliterated. This research, therefore, investigates two methods of recovering laser engraved marks on steel, due to the increase in firearms manufacturing relying on lasers to apply critical markings. This work uses 20 steel plates (CR4 grade), 6 AK-pattern rifle top covers, and a steel pistol slide to investigate the potential for visualising laser engraved marks. All samples had marks applied using a BWM-30F Fibre laser marking machine, in addition to any original manufacture's stamped marks on the pistol. All marks were removed using a grinding belt (plates) and a Dremel® rotary tool (slide and top covers) to average depths of 1200 µm (stamped) and 240 µm (laser engraved). Recovery of the marks was attempted using two techniques to compare the two techniques in their ability to recover laser engraved marks; Regula Forensics® Eddy Current Recovery kit, followed by traditional Fry's reagent. Both recovery techniques recovered 100 % (n = 6) of the stamped characters on the pistol slide, and 0 % (n = 509) of the laser engraved characters on the pistol, top covers and steel plates. Recommendations are made for forensic firearms examiners to avoid attempting the recovery of laser engraved marks using Fry's reagent to preserve the integrity of evidence. It is also suggested that manufacturers avoid laser engraving unique identifying marks on firearms, and to use more permanent methods, such as stamping, to remain compliant with politically binding documents such as the ITI. [ABSTRACT FROM AUTHOR]

Purpose: A novel implant model consisting of meso-scale cactus-inspired spikes and nano-scale bone-inspired trabeculae was recently developed to optimize meso-scale roughness on zirconia. In this model, the meso-spike dimension had a significant impact on osteoblast function. To explore how different nano-textures impact this model, here we examined the effect of different nano-trabecula sizes on osteoblast function while maintaining the same meso-spike conformation. Methods: Zirconia disks with meso-nano hybrid surfaces were created by laser etching. The meso-spikes were fixed to 40 µm high, whereas the nano-texture was etched as large and small trabeculae of average Feret diameter 237.0 and 134.1 nm, respectively. A polished surface was also prepared. Rat bone marrow-derived and human mesenchymal stromal cellinduced osteoblasts were cultured on these disks. Results: Hybrid rough surfaces, regardless of nano-trabecula dimension, robustly promoted the osteoblastic differentiation of both rat and human osteoblasts compared to those on polished surfaces. Hybrid surfaces with small nanotrabeculae further enhanced osteoblastic differentiation compared with large nano-trabeculae. However, the difference in osteoblastic differentiation between small and large nano-trabeculae was much smaller than the difference between the polished and hybrid rough surfaces. The nano-trabecula size did not influence osteoblast attachment and proliferation, or protein adsorption. Both hybrid surfaces were hydro-repellent. The atomic percentage of surface carbon was lower on the hybrid surface with small nano-trabeculae. Conclusions: Small nano-trabeculae promoted osteoblastic differentiation more than large nano-trabeculae when combined with meso-scale spikes. However, the biological impact of different nano-trabeculae was relatively small compared with that of different dimensions of meso-spikes. [ABSTRACT FROM AUTHOR]

Composite MXene-based materials are prone to crack propagation, thus limiting their tensile properties. Numerous efforts have been devoted to removing material constraints and fabricating unitary MXene elastic films. Here, for the first time, inspired by the intestinal wrinkles and villi structure, we presented a ductile, biologically friendly, and highly conductive MXene-based microneedle (MMN) dressing composed of stacked MXene film and superfine microneedle arrays through a simple stretching and laser engraving strategy for wound healing. By utilizing photothermal responsive MXene, periodic porous structures, and a temperature-responsive polymer to construct the MMN dressing, the system can act as an effective route for facilitating controllable drug delivery controlled by near-infrared (NIR) irradiation. In addition, superior conductivity imparts them with the capacity to realize continuous and steady monitoring of motion sensing. The practical performance further demonstrated that the versatile MMN dressing showed obvious therapeutic efficacy in vivo animal wound models. Thus, it is believed that MMN dressings with biomimetic structures, controllable drug release, and conductive pathways will open a new chapter for wound management and widen other practical applications in biomedical fields, such as artificial tendons and soft robotics. MXene-based materials have been demonstrated as critical tools in advancing our understanding of wound healing. However, the rapid crack propagation is a constraint on their tensile properties. Here, inspired by the intestinal wrinkles and villi structure, a single-step method has also been discussed to present a MXene-based microneedle dressing composed of unitary MXene elastic film and superfine microneedle arrays. At the same time, the dressing with biomimetic structures, controllable drug release, and conductive pathways has prospects in intelligent wound management and varieties of related biomedical fields. [Display omitted] [ABSTRACT FROM AUTHOR]

In the present work, a novel algorithm for the continuous projection of point triangles belonging to a triangle mesh is presented. The algorithm uses the normals defined at the vertices of the triangle to perform the projection. The direction of projection is not chosen a priori but depends on the point to be projected: the proposed algorithm, named Fast Continuous Projection method (FCP) lets the projection direction vary continuously on the mesh. Moreover, the direction is coherent with the original surface that is approximated with the triangle mesh. An optimized version of the algorithm is also presented: this uses pre-evaluated matrices to reduce the calculation time. This algorithm can be effectively used when a large set of points has to be projected on a coarse mesh as, for example, to generate the scanning vectors for laser engraving/milling. [ABSTRACT FROM AUTHOR]

In the present study, a finite element method (FEM) simulation model is developed for nanosecond pulsed laser engraving process. The model's novelty lies in the fact that it predicts the actual dimensions of the engraved geometry emphasizing the dimensional deviation due to the defects from kerf formation such as the sloped side walls instead of the intended vertical ones. Simulations were performed and the values of kerf taper angle, top kerf width and bottom kerf width were compared with the corresponding ones from experimental tests made using a LASERTEC 40 laser engraving machine and also were used for process optimization. [ABSTRACT FROM AUTHOR]

Manipulating bubbles (e.g., wettability and transport) underwater is of vital importance in academic exploration and industrial applications. To feed the unique emerging demands such as heat management, greenhouse gas collection and gas evolution reaction, it seems a promising avenue to develop stimuli-responsive materials for the controllability and the adaptation of bubble manipulation. In this review, we firstly introduce the basic theories of bubble manipulation from the aspects of the force analysis. Then, we summarize the recent progress of manipulating bubble by various external stimuli (e.g., thermo, photo, mechanical, electric, magnetic and others). Later, we exemplify some typical methods for the preparation of these surfaces (e.g., replica molding, laser etching, electrochemical method, self-assembly and so on). Furthermore, we provide an overview of potential applications of smart bubble manipulation in various critical fields (e.g., energy, biomedical, environmental and other fields). Lastly, we discuss current challenges and future directions for smart bubble manipulation. [Display omitted] • Bioinspired design and basic theory of bubble manipulation is briefly introduced. • Recent progress of bubble manipulation mediated by external stimuli are summarized. • Potential applications, current challenges and future directions of bubble manipulation are discussed. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of Er:YAG laser on the roughness, surface topography, and bond strength to resin luting cement based on chemical and microabrasion pretreatments of different computer-aided design/computer-aided manufacturing materials. Methods: A polymer-infiltrated-ceramic-network (PICN) material (Vita Enamic, VE), three indirect resin composite (Cerasmart, CS; Shofu HC, SH; Lava Ultimate, LU), and one lithium disilicate ceramic (IPS e.max CAD, EM) blocks were subjected to one of the following pretreatments: no treatment (NC ), Er:YAG etching with one of two powers (either 3 or 6 W), hydrofluoric acid (HF) etching, self-etching ceramic primer (ME), or micro-abrasion (MA). The shear bond strength (SBS) of resin luting cement to pretreated materials was tested. Surface roughness was measured via atomic force microscopy, and surface topography was analyzed via scanning electron microscopy. Two-way analysis of variance, Tukey post-hoc test, and Pearson correlation were applied. Results: Etching EM and VE with HF or the ME resulted in the highest SBS values in their groups (P < 0.05). LU, SH, VE, and CS indicated similar SBS values when treated with 3 W, 6 W, and MA. The highest surface roughness (Sa ) values were obtained for the LU, CS, and VE groups when treated with 6 W, whereas the lowest Sa values were obtained for CS when treated with the ME and EM when treated with the ME or 3 W. Only SH and CS indicated a significant correlation between surface roughness and bond strength. Conclusions: Er:YAG laser etching is comparable to micro-abrasion when treating resin composite blocks and may induce fewer surface cracks. HF etching remains the gold standard for the treatment of glass-based ceramics and PICNs. [ABSTRACT FROM AUTHOR]

Aim: Recent reports indicate that deproteinization of acid-etched dentin surface can extend penetration depth of adhesive agents. The main goal of the present research was to investigate the deproteinization effect of Nd:YAG and diode 940 lasers on acid-etched dentin and microleakage grade in class V composite restorations. Methods: 36 extracted human premolar teeth were selected to make standard buccal and lingual class V cavities. These samples were randomly split into three sub-groups: 1.Control group, in which composite was applied for restoration after etch and bonding process without deproteinization; 2.Nd:YAG laser group, in which the teeth were deproteinized with Nd:YAG laser after etching and painting internal surfaces of cavities with Van Geison stain and then composite restorations applied just as control group; 3.Diode laser group, in which the process was similar to Nd:YAG laser group, but instead, diode 940 laser was irradiated. The teeth were bisected into two equal longitudinal buccal and lingual halves. Marginal microleakage of samples was scored by using a stereomicroscope. Kruskal-Wallis, Mann-Whitney U and Fisher's statistical tests were employed for analysis of the obtained data. Results: A significant reduction in marginal microleakage was observed for both groups treated with laser (Nd:YAG and diode 940)compared to control (p=0.001 & p=0.047). There was no significant difference in marginal microleakage between Nd:YAG laser and diode 940groups (P = 0.333). Conclusion: Nd:YAG and diode 940 laser deproteinization of acid-etched dentin decreased the marginal microleakage of in-vitro class V resin composite restorations. [ABSTRACT FROM AUTHOR]

Abstract Background Promoting the directional attachment of gingiva to the dental implant leads to the formation of tight connective tissue which acts as a seal against the penetration of oral bacteria. Such a directional growth is mostly governed by the surface texture. Material and methods In this study, three different methods, mechanical structuring, chemical etching and laser treatment, have been explored for their applicability in promoting cellular attachment and alignment of human primary gingival fibroblasts (HGFIBs). Results The effectiveness of mechanical structuring was shown as a simple and a cost-effective method to create patterns to align HGIFIBs. Conclusion Combining mechanical structuring with chemical etching enhanced both cellular attachment and the cellular alignment. [ABSTRACT FROM AUTHOR]

Copyright of China Textile Leader is the property of China Textile Information Center 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.)

Copyright of China Textile Leader is the property of China Textile Information Center 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.)

The aim of this study was to compare the effect of Er:YAG laser irradiation and adhesive systems on the microtensile bond strength (μTBS) of flowable resin to dentin. The flat dentin surfaces of 30 wisdom molar teeth were randomly divided into 3 groups (n= 10): no laser etching (control), laser etching using QSP and MSP modes. After the application of the flowable and the composite resin, and 5,000 thermal aging, the μTBS results were analyzed with two-way analysis of variance and Tukey's honest standard of difference (HSD) tests. There were no significant differences between the μTBS of the self-etch group and the total-etch groups for MSP (p>0.05). MSP mode is a useful pulse mode for dentin surface treatment due to elimination of the acid-etching step. [ABSTRACT FROM AUTHOR]

Zirconia is an important dental implant material, yet it surfaces milling method is still under investigation. To explore the feasibility of laser etching in processing fine micro grooves on the surface of zirconia and to observe fine micro groove structure' influence on mouse embryonic osteoblasts, the survey was conducted. 31 zirconia discs were made and polished to mirror surface. Then, they were divided into 3 groups: the mirror group, the femtosecond laser ablated microgroove group and the air blasted + acid etched group. Then, the surface properties of zirconia discs were analyzed by Scanning Electron Microscope/Energy Dispersive Spectrometer (SEM/EDS), X-Ray Diffraction (XRD), Atomic Force Microscope (AFM), water contact angle test and micro-Vickers hardness test. The biocompatibility of each machined zirconia was tested by cell proliferation test and SEM analyze of cell morphology. Then, the effect of these surface treatment to MC-3T3-E1's osteogenic differentiation was evaluated by Q-PCR test. SEM image showed that the femtosecond laser is a reliable method for forming regular-arranged microgrooves with pitch width of around 5 μm. EDS and XRD indicated that there were stable and purified tetragonal crystal system on the laser-roughened surface. AFM suggested that laser machining generated rougher surface (Ra) (271.7 ± 67.2 nm) than other groups. Furthermore, the contact angle showed laser ablated grooves induced anisotropic wetting. The micro-Vickers hardness test ascertained that laser-ablation strengthened zirconia surface. In vitro experiment showed that MC-3T3-E1 grown along the long axis of microgrooves on the first day. Besides, Real time PCR implied that osteogenesis-related gene expression OPN and ALP was much higher than the rest groups. Femtosecond laser is able to machine zirconia with ultra-fine microgrooves (around 2.5 μm). These structures promoted MC-3T3-E1 cell to line along the microstructure and differentiate into osteogenic cells. Thus, femtosecond laser might be a potential processing options for zirconia micro-texturing. [Display omitted] • Femtosecond laser ablation created ultra-fine grooves (<10 μm) on zirconia materials. • Tested the property changes of femtosecond laser ablated ultra-fine grooves on zirconia materials. • Ultra-fine grooves on zirconia materials guide MC3T3-E1 cell to line along the long axis of the grooves. • Ultra-fine grooves on zirconia materials promote MC3T3-E1' osteogenic differentiation. [ABSTRACT FROM AUTHOR]

Patterned composites with custom-tailored properties are essential for efficient thermal management required by the increasing integration and complexity of devices. In this work, a facile approach for the fabrication of functional, robust, and patterned composites was demonstrated using a simple and scalable laser engraving technique. Graphene patterns were incorporated into composites by the single- or multiple-lasing on poly(Ph-ddm) substrate. The resultant composites exhibited a high thermal conductivity (8.2 W/(m·K)) that was equivalent to an enhancement of 45 times compared to pure matrix. This increase was attributed to the formed high-quality graphene porous architecture, which established an effective heat conduction channel. With the merit of computer-aided design of the laser trajectory, the processing method offers the freedom to tailor the heat transfer pathway in composites. Besides, the composites presented the favorable Joule heating performance in terms of fast and stable response with the heating efficiency up to 276 °C‧cm2/W. More interestingly, the heaters with designable thermal patterns were also allowed, in which the electrical property of each heating unit could be tailored by adjusting laser parameters. This provides a unique opportunity to simulate the real case of non-uniform heat sources in many electronic devices, which will facilitate the design and development of heating dissipation systems. The material/process developed promises a wide range of possibilities for the efficient thermal management applications. [Display omitted] • Patterned functional composites are developed for efficient thermal management using a simple laser engraving technique. • The resultant composites have a high thermal conductivity (8.2 W/(m·K)) that is 45-fold higher than that of neat resin. • The processing method offers the freedom to tailor heat transfer pathways in composites. • Designable heaters are proposed to simulate the real case of non-uniform thermal distribution of electronic components. [ABSTRACT FROM AUTHOR]

In this paper, the novel surface effects of fashion garments through CO2 laser engraving treatment were investigated. To improve the visual appearance, the wool/polyester blended fabric was treated with ideal parameters including resolution (dpi) and pixel time (μs). The physical properties, which include weight, thickness, air permeability, thermal conductivity and tear strength, were evaluated in accordance with international specifications. This study reveals the potential of feasible fashion designs through laser engraving. The computer-aided design method can open up new possibilities for green fashion design. It is believed that fashion design with rich artistic appearances such as patterns, colors and textures can cater for fashion industries and the process can facilitate quick responses to the market. [ABSTRACT FROM AUTHOR]

Many regions of subsurface interest are, or will be, fractured. Seismically characterizing these zones is a complicated but essential task for resource development. Physical modeling, using ultrasonic sources and receivers over scaled exploration targets, can play a useful role as an analog for reservoir imaging and assessment. We explored the anisotropic response of glass blocks containing internal fractures created by a novel laser-etching technique. We compared transmitted and reflected signals for P- and S-waves from fractured and unfractured zones in a suite of ultrasonic (1-5 MHz) experiments. The unaltered glass velocities have averages of 5804 and 3447 m/s for P- and S-waves, respectively (giving VP/VS = 1.68). The unfractured glass has a very high quality (Q) factor of over 500 for P-waves and S-waves. The fractured zones have a small (up to 1.5%) velocity decrease. Signals propagating through the fractured zone have diminished amplitudes and increased coda signatures. Reflection surveys (zero-offset and with variable polarizations) record significant scatter from the fractured zones. The fracture-scattered energy can be migrated to provide a sharper image. The glass specimens with laser-etched fractures display a rich anisotropic response, which can help inform field-scale imaging. [ABSTRACT FROM AUTHOR]

Abstract: Machining with ultrafast laser pulses demands the selection of correct conditions to obtain precise, and yet, efficient material extraction, in which the control of volume and physical state of the matter being etched is fundamental. Usually, the production of volumetric structures needs overlapping of many pulses, and the incubation effects and its dependence on process parameters are of prime importance. Hence, in this work this parameter and the damage thresholds for many different pulses overlapping were measured for some optical glasses with an alternative method which is faster than the traditional one, and is closer to the real machining condition. [Copyright &y& Elsevier]

This paper sumarizes the data preprocessing methods used for modelling of laser beam impact. At the beginning, it gives a short overview of physical background of interaction between a laser beam and processed material. Also the input data sets are described and the way of their acquisition is shown, so that the reader could get a good idea of the whole problem. The main content of the paper is formed by description of the data preparation process that consists of several steps - automatic heat-affected area detection, samples parameterization and their surface approximation. In all cases our methods with the best results are described in a detail. At the end of the paper, our results are summarized, discussed and possible plans for the future research are introduced. [ABSTRACT FROM AUTHOR]

In today's fashion world, technology has taken on an important role for the creation of novel design effects. As a type of digital technology, laser engraving is applied for decorative purposes with unique fashion design looks. With this technology, simple and complex patterns can be engraved onto the surface of garments by using laser beam scanning. This study explores the application of laser technology on assembled garments for diverse engraved patterns. To improve the visual appearance, different design methods, such as the graphic and resist methods, are applied for carbon dioxide (C02) laser engraving onto garments made from rayon/polyester blended fabric with optimal laser engraving parameters, including resolution (dpi) and pixel time (ps). This study also reveals the many potential of fashion designs through the use of laser engraving technology. Based on computer-aided design, laser engraving could open up new possibilities for green fashion design with distinct patterns and textures that would cater to the demands of industries and consumers. [ABSTRACT FROM AUTHOR]

Copyright of China Textile Leader is the property of China Textile Information Center 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.)

We proposed a novel method of fabricating polydimethylsiloxane (PDMS) microfluidic chip polymer master molds in this paper. The method mainly includes two steps. First, a stainless steel slice was laser etched to form a metal model. Then, the organic solution of poly(methyl methacrylate) (PMMA) was casted onto the metal model to fabricate the PMMA master which subsequently would be used to fabricate PDMS chips. We systematically researched different laser parameters influencing the surface status of microchannels and obtained optimized etching parameters. We investigated and optimized the organic solution composition of PMMA while casting chip masters, and developed a method to form fine polymer masters using two different viscosity solutions to cast the model in turn, and studied the repeatable replication. Then, we investigated physical performance of this chip and evaluated the practicability by analyzing Rhodamine B. Compared with present methods, the proposed method does not need photolithography on photoresistant and chemical etching. The entire fabricating progress is simple, fast, low-cost and can be controlled easily. Only several minutes are required to make a metal model, 3 hours for a PMMA master, and one day for PDMS chips. [ABSTRACT FROM AUTHOR]

Plasma sprayed coatings have been investigated as field emission cathodes. The tested materials were Al2O3+13%TiO2, Al2O3+40%TiO2, TiO2, Some of these coatings were laser engraved. The samples used were initially prepared for purposes other than field emission and their components and structures were not optimised for electron emission. The emission properties were evaluated from current-voltage characteristics taken in a diode configuration in a vacuum chamber under a pressure of 1x106 Pa. Preliminary results indicate that some layers are good field emitters (threshold field 1x107 V/m for Al2O3+13%TiO2). The emission stability was generally good and the emission curves were similar on repetition. No significant hysteresis in I-V plots for "up-and-down" measurements was noticed. A model of possible mechanism of low microscopic field emission is presented and microstructural investigations using techniques of XRD, Raman spectroscopy and SEM techniques of plasma sprayed and laser engraved layers enabled understanding of increase of field enhancement factor. [ABSTRACT FROM AUTHOR]