Laser Exposure Duration Research Articles

In vitro Effect of Low-level Lasers on Proteomic Concentration in Human Blood Plasma Using 375 nm and 650 nm Lasers

Abstract Background: As a continuation of earlier laboratory research and its findings, we are studying the effects of biostimulation and alteration on human blood plasma to improve blood circulation in blood vessels, treat some infections, and treat various diseases, including blood protein-related ones. Methods: Blood samples were collected through venipuncture into tubes containing, ethylenediaminetetraacidic as an anticoagulant from healthy adult donors, and plasma was separated from blood components. Blood plasma samples were irradiated for varying periods (5, 10, 15, and20) min. Before and after irradiation, total protein and albumin concentrations were calculated using 375 nm and 650 nm lasers. Using a spectrophotometer, the concentration of total protein and albumin was determined for each sample. Results: At the (375 and 650) nm laser wavelength and exposure durations of (5, 10, 15, and 20) min, it was observed that the total protein concentration had significant differences between pre- and postirradiation probate value (P = 0.05, P = 0.05, P = 0.05, and P = 0.05, respectively). It was observed that the total protein and albumin concentrations had significant differences between pre- and postirradiation. In addition, the results demonstrate that the concentration of total protein and albumin decreases more significantly at a laser wavelength of 650 nm compared to a laser wavelength of 375 nm at times of (5 and 10) min. Conclusions: Our results clearly indicate that low-level lasers with different wavelengths of ( 375 , 630) nm both affect the concentration of total protein and albumin in human blood plasma, which can contribute to the treatment of many pathological conditions in the future.

Exploring the efficacy of laser-assisted in-office tooth bleaching: A study on varied irradiation times and power settings utilizing a diode laser (445 nm)

The aim of this study was to evaluate the effectiveness of a laser-assisted in-office tooth bleaching treatment, employing a diode laser (445 nm) using different power and time settings. Two hundred human incisors were collected for evaluating tooth color change (ΔΕ00) and whiteness index in dentistry (ΔWID) following laser-assisted tooth bleaching treatment. The specimens were distributed into 25 groups (n = 8) according to laser output power (0.5–2 W) and duration of irradiation (10–60 s) that was applied. ΔΕ00 and ΔWID were evaluated using a spectrophotometer at three points of time (24 h, 1 week and 1 month after treatments). Three-way ANOVA revealed that power, duration of laser irradiation, and time of measurement after bleaching treatments significantly affected both ΔΕ00 and ΔWID(p < 0.05). Furthermore, laser irradiation increased ΔΕ00 and ΔWID at all applied powers compared to the control group (p < 0.05), but this increase was dependent on the duration of irradiation. Laser irradiation significantly increased ΔΕ00 when the duration of operation was 50–60 s at 0.5–1 W, while at 1.5–2 W was significantly increased when the duration was 30–60 s. ΔWID was significant higher in the laser groups compared to the control group at all powers, except for 0.5 W where it was significant higher when the duration was 50–60 s. The outcomes of the study can help in selecting the suitable power settings and duration of laser exposure to achieve the optimal whitening results while ensuring the safety of the tooth pulp.

The Effect of Laser Power and Laser Exposure Time for Cavity Created on Al2O3 Ceramic Surface

Al2O3 ceramic materials have many industrial applications, especially because they are wear-resistant. In this study, dimples of different sizes were formed on the surface of ceramic plates with a CO2 laser. The effects of laser power and laser exposure time on the dimensions of the cavity were investigated. For this purpose, laser powers of 40, 52, 65, 78, 91, and 105 W were applied to the ceramic material for 10 seconds. In addition, 80 W laser power was kept constant and the laser beam was sent to the material for 1, 5, 10, 15, 20, 25, and 30 seconds. High-resolution images of the resulting cavities were taken with an optical microscope. Using the images, the dimensions of the cavities were measured and the effects of laser power and laser exposure time on the cavity geometry were observed. The effects of both laser power and laser exposure duration on the cavity and Heat Affected Zone (HAZ) regions showed similar characteristics. The size of the cavities and HAZ increased almost linearly as laser power increased. However, when the effect of laser exposure duration was analyzed, the increase in cavity sizes slowed down after the exposure duration exceeded 10 s. When the laser exposure duration exceeded 15 seconds, it was observed that the dimensions of the cavities did not change.

Effect of mitomycin C on the corneal endothelial cells of Saudi patients with myopia after transepithelial photorefractive keratectomy: a two-armed cohort study.

To study the effect of mitomycin C (MMC) applied during transepithelial photorefractive keratectomy (TPRK) on the corneal endothelium one week (W1) and three months (M3) after surgery and its determinants. In this two-armed cohort study conducted in 2022, eyes treated with MMC during TPRK (group 1) were compared with eyes not treated with MMC (group 2). The corneal endothelial cell (EC) count, EC density (ECD; cells/mm2), average (µm2), standard deviation (µm2), coefficient of variation (CV%), ECmax, ECmin, and EC percentage of hexagonality were estimated at W1 and M3. The postoperative changes in the EC count in the two groups were compared and correlated with the other independent variables. Group 1 had 26 eyes, and group 2 had 78 eyes. All TPRK indices were significantly higher for the eyes in group 1 than for those in group 2. The MMC usage was not a significant predictor of the change in ECD (P=0.644), change in CV (P=0.374), and change in the percentage of hexagonality of EC (P=0.164) at W1. However, the use of MMC was a significant predictor of changes in CV (P=0.014) and the change in the percentage of hexagonality of EC (P=0.039) at M3. The duration of laser exposure and the size of the optical zone influenced the correlation of MMC use with the changes in EC indices, postoperatively. The use of MMC doesn't affect ECD, CV, and percentage of hexagonality at W1 if other surgical indices are considered. At M3 after operating myopic eyes by TPRK, MMC significantly influence the CV and percentage of hexagonality. The duration of the laser application and the size of the optical zone should be considered when determining the effect of MMC on the EC indices.

Selective oxidation of metallic contacts for localized chemical vapor deposition growth of 2D-transition metal dichalcogenides

Chemical vapor deposition (CVD) is the most common fabrication method for transition metal dichalcogenides (TMDs) where direct chemical vapor phase reaction between an oxide transition metal and chalcogen powder results in formation of high-quality crystals of TMDs. However, in this method the nucleation is often random with incomplete nucleation and non-uniform thickness. In this work we studied the formation of a localized transition metal oxide which resulted in controllable growth of mono- to few-layer MoS2 around the formed oxide region. Bulk molybdenum patterns were irradiated with a 532 nm continuous wave laser creating a localized hot-spot which, under ambient conditions, resulted in the formation of molybdenum oxide. The characteristics of the subsequent MoS2 growth depended on the type and thickness of the MoOx which was determined by the power and duration of laser exposure. The resulting MoOx and MoS2 growth around the localized oxide regions were investigated by Raman and photoluminescence spectroscopy. Our studies have shown that exposing bulk molybdenum patterns to 10 mW of laser power for about 2s results in the minimal formation of MoO2 which coincides with high quality mono- to few-layer MoS2 growth.

Using CO2 Laser, Optimization of Laser Power, Exposure Time and Frequency for Cavity Formation on Hardox Steel Plate

The texture of the surfaces of materials causes changes in mechanical properties such as friction. Micro-scale cavities have been created on Hardox steel plate, which has recently been the focus of attention in demanding applications with its hardness, toughness and wear resistance. CO2 laser was used in the cavitation process on the surface and the power, exposure and frequency of the laser used were optimized to obtain a cavity with the desired geometry. Taguchi method was used in the optimization process. In addition to obtaining the optimum parameters, the effect ratios of the parameters were also calculated. Optimum laser parameters were obtained as 5 s for laser exposure duration, 60 W for laser power, and 50 kHz for laser frequency. According to the optimization calculations, the parameter with the highest effect on the result was laser exposure duration with a rate of 71,86 %. Laser power and laser frequency affected the result by 23.02 % and 5.12 % respectively.

Determination of the CO2 Laser Parameters on Dimple Geometry on Al2O3 Ceramic Surface

Dimples on Al2O3 ceramic plates were created with a CO2 laser using different laser parameters. The effects of the laser parameters used on the dimple geometry were investigated and the necessary laser parameters were optimized to obtain the desired dimple geometry. Taguchi method was used in the optimization process. The effects of laser power, scan speed and laser frequency from laser parameters were investigated. Optimum laser parameters were determined as a result of the Taguchi Optimization method. In addition, the laser parameter with the highest effect on the result was determined. Optimum laser parameters were obtained as 60 W for laser power, 35 s for laser exposure duration and 50 kHz for laser frequency.

Surface quality improvement of steel parts by combined laser-ultrasonic treatment: determination algorithm of technological parameters

To provide the quality of the surface layer and improve operational properties, a combined laser-ultrasonic surface hardening and finishing technology of steel products is proposed. This work is devoted to determining the range of rational parameters of laser heat treatment and ultrasonic impact treatment for enhancing the complex hardening process of AISI 1045 steel and AISI D2 steel. Laser surface transformation hardening was carried out with a constant temperature strategy using a fiber laser and scanning optics at a heating temperature of 1200–1,300 °C and a processing speed of 40–140 mm/min. Ultrasonic surface hardening and finishing were performed on technological equipment with an amplitude of ultrasonic vibration of 18 μm and a load of the ultrasonic tool of 50 N. The ultrasonic treatment duration varied from 60 to 180 s. The results showed that laser-ultrasonic treatment leads to an increase in the hardening intensity by more than 200 %, forming a hardening depth of 200–440 μm. Combined treatment leads to a significant increase in wear resistance due to the formation of ultrafine-grained martensitic microstructure with hardness (58–60 HRC5) in the near-surface layer. The combined laser-ultrasonic hardening process control algorithm for surface treatment of structural and tool steels is proposed, limiting the heating temperature, the duration of laser (ultrasonic) exposure, and the vibration amplitudes of the ultrasonic horn. Laser-ultrasonic treatment will allow the formation of a surface layer with a given set of properties, providing increased wear and corrosion resistance. The developed technology can be used for surface hardening and finishing of large-sized steel products in the mechanical engineering industry.

Optical microfibers integrated with evanescent field triggered self-growing polymer nanofilms.

Hybrid optical fibers have been widely investigated in different architectures to build integrated fiber photonic devices and achieve various applications. Here we proposed and fabricated hybrid microfiber waveguides with self-growing polymer nanofilms on the surfaces of microfibers triggered by evanescent field of light for the first time. We have demonstrated the polymer nanofilm of ∼50 nm can be grown on the microfiber with length up to 15 mm. In addition, the roughness of nanofilm can be optimized by controlling the triggering laser power and exposure duration, and the total transmission loss of the fabricated hybrid microfiber is less than 2 dB within a wide wavelength range. The hybrid polymer nanofilm microfiber waveguides have been characterized and their relative humidity (RH) responses have also been tested, indicating a potential for RH sensing. Our fabrication method may also be extended to construct the hybrid microfibers with different functional photopolymer materials.

Laser-Induced Damage Threshold of Single Crystal ZnGeP2 at 2.1 µm: The Effect of Crystal Lattice Quality at Various Pulse Widths and Repetition Rates

The ZnGeP2 crystal is a material of choice for powerful mid-IR optical parametric oscillators and amplifiers. In this paper, we present the experimental analysis of the optical damage threshold of ZnGeP2 nonlinear crystals induced by a repetitively-pulsed Ho3+:YAG laser at 2091 nm. Two types of ZnGeP2 crystals grown under different conditions were examined using the laser and holographic techniques. The laser-induced damage threshold (LIDT) determined by the pulse fluence or peak intensity was studied as a function of the pulse repetition rate (PRR) and laser exposure duration. The main crystal structure factor for a higher LIDT was found to be a reduced dislocation density of crystal lattice. The ZnGeP2 nonlinear crystals characterized by the high structural perfection with low density of dislocations and free from twinning and stacking faults were measured to have a 3.5 J/cm2 pulse fluence damage threshold and 10.5 MW/cm2 peak intensity damage threshold at 12 kHz PRR; at 40 kHz PRR the pulse fluence damage threshold increased to over 6 J/cm2, but the peak intensity damage threshold dropped to 5.5 MW/cm2.

Photodynamic Therapy 405 nm Diode Laser as Antibacterial for Cavity and Root Canal Sterilization

Background: The goals of caries restoration and endodontic treatment are to repair and prevent the infection fromgetting worse and if possible, heal the damaged tissue. To achieve this goal, it is necessary to control the presence ofmicrobes in the cavity or root canals with chemo mechanics prior to filling or obturation of the root canals. Disinfectionmethods using disinfectants with effective bactericidal activity are mostly used at subtoxic levels and at concentrationswhere their toxicity is a significant factor. In addition, the disinfection method is considered unable to achieve thoroughcavity cleaning and causes secondary infection. A new method to provide better disinfection without cytotoxic effectshas recently been discovered using the photodynamic method of 405 nm diode laser therapy. Research continues and isprogressing with the existence of various factors that affect the effectiveness of the 405nm diode laser as an antibacterial.Purpose: To evaluate the results of research on photodynamic diode laser therapy with a wavelength of 405 nm as acombination antibacterial therapy in cavity and root canal sterilization techniques. Review(s): Literature study in the formof narrative review using libraries obtained through the PubMed and Google Scholar databases. The optimal bacterialmortality was influenced by the form factor of the target bacteria, the energy dose and duration of laser exposure, and thetype of photosensitizer used. Conclusion: The use of a 405 nm diode laser with an energy power of 50 mW with a distanceof 20 mm can degrade biofilms Streptococcus mutans up to 100% using erythrosine photosensitizer, for 75 seconds. Andwith the same power and distance, it can degrade the biofilm of bacteria Enterococcus fecalis up to 97.51%, using aphotosensitizer chlorophyll, for 120 seconds.

Optimization of intracellular macromolecule delivery by nanoparticle-mediated photoporation

Nanoparticle-mediated photoporation is a novel delivery platform for intracellular molecule delivery. We studied the dependence of macromolecular delivery on molecular weight and sought to enhance delivery efficiency. DU145 prostate cancer cells were exposed to pulsed laser beam in the presence of carbon-black nanoparticles. Intracellular uptake of molecules decreased with increasing molecular weight. Attributing this dependence to molecular diffusivity, we hypothesized that macromolecular delivery efficiency could be enhanced by increasing either laser fluence or laser exposure duration at low fluence. We observed increased percentages of macromolecule uptake by cells in both cases. However, trade-off between cell uptake and viability loss was most favorable at low laser fluence (25-29 mJ/cm2) and longer exposure durations (4-5 min). We conclude that long exposure at low laser fluence optimizes intracellular macromolecule delivery by nanoparticle-mediated photoporation, which may be explained by longer time for macromolecules to diffuse into cells, during and between laser pulses.

NIR-Controlled Treatment of Multidrug-Resistant Tumor Cells by Mesoporous Silica Capsules Containing Gold Nanorods and Doxorubicin.

Multidrug resistance (MDR) is identified as a major impediment to the efficient chemotherapy of cancer, and considerable endeavors have been devoted to reverse MDR containing structuring varieties of multifunctional nanocarriers. Here, a specially light-activated hollow mesoporous silica nanocontainer with an in situ-synthesized Au nanorod (AuNR) core and a surface-modified hairpin structure DNA gatekeeper is reported for treating MDR tumor cells. In this system, the AuNR only fills part of the space in hollow mesoporous silica due to its controllable size, and the remaining space is used to load enough DOX. By controlling the near-infrared (NIR) laser intensity and exposure duration, the configuration of hairpin-structured DNA (Tm = 51.4 °C) can change reversibly and then trigger the controllable intracellular release of DOX, leading to a significantly enhanced chemotherapeutic efficacy and adjustable photothermal treatment for multidrug-resistant cancer cells. The in vitro experiments showed that this system could effectively overcome the MDR of HepG2-adm cells (a MDR cell line of human hepatocarcinoma cells) by the increased concentration of DOX intracellularly and the photothermal conversion of AuNRs, even at a low concentration (e.g., 30 μg mL-1). Therefore, this NIR-triggered chemo-photothermal synergistic treatment system can be used as a promising efficient strategy in reversing the multidrug resistance for cancer therapy.

Effects of Energy Parameters on Dimensional Accuracy When Joining Stainless-Steel Powders with Heterogeneous Metal Substrates

This work presents some breakthroughs for obtaining high dimensional accuracy and reliable geometrical tolerance in the joining of stainless-steel powders with heterogeneous substrates. In the laser melting process, the interfacial energy fractions and forces acting at the solid–liquid surface of the melting powders can effectively vary their geometrical shapes and positions before they turn into the liquid phase. When the interfacial free energy is low, the melting powders are near molten, thus the successive volumetric changes can alter the layered geometry and positions. This assumption was validated by a powder-bedding additive manufacturing process to consolidate stainless-steel 316L powders (SLM 316L) on a thin heterogeneous stainless-steel substrate. Experiments were carried out to reveal the effects of the process parameters, such as laser power (100–200 W), exposure duration (50–100 µs) and point distance (35–70 µm) on the resulting material density and porosity and the corresponding dimensional variations. A fractional factorial design of experiment was proposed and the results of which were analyzed statistically using analysis of variances (ANOVA) to identify the influence of each operating factor. High energy densities are required to achieve materials of high density (7.71 g/cm3) or low porosity (3.15%), whereas low energy densities are preferable when the objective is dimensional accuracy (0.016 mm). Thermally induced deflections (~0.108 mm) in the heterogeneous metal substrate were analyzed using curvature plots. Thermally induced deformations can be attributed to volumetric energy density, scanning strategy, and the lay-up orientation. The parametric optimizations for increasing in dimensional accuracy (Z1: ~0.105 mm), or in material density (~7.71 g/cm3) were proven with high conversion rates of 88.2% and 96.4%, respectively, in validation runs.

Treating Oral Lichen Planus: current evidence and future perspectives

Treating Oral Lichen Planus: current evidence and future perspectives

Клинико-эпидемиологические и терапевтические аспекты ретинопатии недоношенных детей

Relevance of the study . Blindness and hypovision due to retinopathy of prematurity dominate in the structure of the causes of visual impairment from childhood in both developed and developing countries, despite all the achievements of science and practical medicine. A huge role in preventing blindness from retinopathy of prematurity belongs to the effectiveness of treatment. The most discussed topic among global ophthalmology community is readings and the time of laser coagulation of the eye retina. Aim of the study . To evaluate the advantages and disadvantages of laser coagulation various methods in retinopathy of prematurity, to determine the most optimal method in the treatment of active phases of the disease. Materials and methods . We consider retinopathy of prematurity modern methods of diagnosis and treatment, also we carry out advantages and disadvantages comparative analysis. We consider the organization statistics of ophthalmic care for premature infants in the Tambov Region and the long-term treatment results of premature infants with retinopathy of prematurity. Results and discussion . The generally accepted standard methodology applied for screening examination, is the reverse binocular ophthalmoscopy (possible in humidicrib) when medication dilate pupils. If necessary, an examination is carried out using the retinal pediatric camera “RetCam Shuttle” (Clarity Medical Systems Inc., USA), which allows to document and save the survey results in a database. To date, timely and sufficient laser coagulation of the avascular zone of the retina is the only proven effective method of active retinopathy of prematurity treatment. The most modern method of retinal laser coagulation is the technology of pattern scanning laser coagulation, which automated the procedure for applying coagulants. The main trends in the retinopathy of prematurity treatment are earlier implementation of laser coagulation and over dosed coagulation, according to the ETROP recommendations. When using a pattern laser system, laser pulses are delivered in sequence at the highest speed. The result of the use of this technology is a high accuracy of coagulation, so that the eye retina receives the least energy impact, compared with the classical laser coagulation. Conclusion. 1. Timely and adequate laser coagulation of the avascular areas of the eye retina reduces the risk of severe anatomical and functional outcomes of active retinopathy of prematurity. 2. The use of the technology of transpupillary scanning pattern laser coagulation of the eye retina (PASCAL) can significantly reduce the duration of laser exposure and anesthesia for a premature baby, improve the efficiency and safety of treatment.

Kinetics of cell death triggered photothermally using folate-conjugated gold nanoparticles and various laser irradiation conditions in cancer cells

Introduction: In this study, we explore in detail cell-specific targeting efficacy of nano-photo-thermal therapy (NPTT) method and the resulting responses that are induced by variable laser intensities and exposure times in cancer cells to induce selective apoptosis. We delineate the synthesis of a high-yielding synthetic F-AuNPs by tailoring the surface of gold nanoparticles with folic acid to enhance cell selectivity and specificity. Materials and Methods: For this purpose, synthesized F-AuNPs treated cells were irradiated with various laser intensities and exposure duration. Both KB cancer cells, as a folate receptor over-expressing cell line, and L929 normal cells, with low level of folate receptors were used. Following various regimes of NPTT, Cytotoxicity was assessed by MTT assay and comparison of induced apoptosis and necrosis in population of cells were depicted by Annexin/PI staining. Results: We report no significant cytotoxicity difference between KB and L929 cell lines at concentrations up to 40 μM of F-AuNPs. Moreover, no significant cell lethality occurred for various laser irradiation conditions. However, in photothermal therapy, the viability of KB and L929 cells was 57% and 83%, respectively. Flow cytometry clearly revealed the kinetics of cell death. The majority of cancer cell death was related to apoptosis (41% apoptosis of 43% overall cell death). Conclusion: Together, these findings confirm that F-AuNPs based NPTT can either induces cell death via apoptosis or necrosis. The main factor determining whether a cell will die due to apoptosis or necrosis on-demand with PTT depends on laser heating level. Our main target must be to only trigger apoptosis during PTT by using suitable irradiation conditions. As a result, folate targeting ability of the F-AuNPs and laser energy threshold to induce selective apoptosis in cancer cells were shown.

Probabilistic retinal exposure model

Exposure of retinal tissue to a laser source requires two conditions: the person must be exposed to the laser beam and the laser must be in his/her optical field-of-view. The authors have developed a probabilistic model for the second condition. This model is based on random eye movements, known as saccades, about a look direction. This direction is an input to the model and is known either from head orientation or a task. The model calculates the instantaneous probability that the laser is in the optical field-of-view of the retinal tissues of fovea, macula, and retina. Because of saccades, the location of exposure will change several times a second. The duration of laser exposure for the look direction is then used to calculate the probability that the retinal tissue is exposed at least once, based on independent exposures from the saccades. The concepts and equations of the model are presented, along with example calculations from applying the model to a specific exposure scenario. For a given retinal tissue optical field-of-view, the primary contributor to the probability of exposure is the angle between the look direction and the laser.Exposure of retinal tissue to a laser source requires two conditions: the person must be exposed to the laser beam and the laser must be in his/her optical field-of-view. The authors have developed a probabilistic model for the second condition. This model is based on random eye movements, known as saccades, about a look direction. This direction is an input to the model and is known either from head orientation or a task. The model calculates the instantaneous probability that the laser is in the optical field-of-view of the retinal tissues of fovea, macula, and retina. Because of saccades, the location of exposure will change several times a second. The duration of laser exposure for the look direction is then used to calculate the probability that the retinal tissue is exposed at least once, based on independent exposures from the saccades. The concepts and equations of the model are presented, along with example calculations from applying the model to a specific exposure scenario. For a given retinal ...

Quantitative analysis of mitoflash excited by femtosecond laser.

Mitochondrial oxidative flashes (mitoflashes) are oxidative burst events in mitochondria. It is crosslinked with numerous mitochondrial molecular processes and related with pivotal cell functions such as apoptosis and respiration. In previous research, mitoflashes were found as spontaneous occasional events. It would be observed more frequently if cells were treated with proapoptotic chemicals. We show that multiple mitoflashes can be initiated by a single femtosecond-laser stimulation that was tightly focused on a diffraction-limited spot in the mitochondrial tubular structure. The mitoflash events triggered by different photostimulations are quantified and analyzed. The width and amplitude of mitoflashes are found very sensitive to stimulation parameters including laser power, exposure duration, and total incident laser energy. This study provides a quantitative investigation on the photostimulated mitoflashes. It may thus demonstrate such optical method to be a promising technique in future mitochondrial research.

Drilling of crack free micro holes in glass by chemo-thermal micromachining process

Recent achievements made in the field of ceramics and glass technology demands the development of hybrid techniques to process those advanced materials precisely and efficiently. Chemo-thermal micromachining is a novel method of micro-fabrication, achieved by integrating laser based thermal ablation and chemical etching. This hybrid process involves focusing laser beam on a borosilicate glass specimen submerged in aqueous sodium hydroxide solution that causes chemical machining along with thermal ablation at the focused point. In this study, an attempt has been made to explore the effects of machining parameters like laser power, laser exposure duration and electrolyte concentration on material removal rate (MRR) and surface quality that involves study of surface cracks and built-up edges along the machined surface of borosilicate glass. A four-level full factorial experimental design was adopted to understand the effect of each parameter. Additional experiments have been conducted to identify the effect of laser and chemical machining separately. It was found that there was a reduction of about 90% in the average length of crack in chemo-thermal micromachining process as compared to laser ablation alone. Also, the number of cracks was reduced from about 20-23 in laser machining to 1–5 in this hybrid machining.