Advanced methylene blue - nanoemulsions for in vitro photodynamic therapy on oral and cervical human carcinoma.

Photodynamic therapy (PDT) is a therapeutic modality with high contributions in the treatment of cancer. This approach is based on photophysical principles, which presents as a less invasive strategy than conventional therapies. Combined with nanotechnology, the therapy becomes more efficient because nanoparticles (NPs) have advantageous characteristics such as biocompatibility, controlled, and targeted release, promoting solubility and decreasing the toxicity and side effects involved. In this work were developed nanoemulsions containing the methylene blue photosensitizer (MB) (MB/NE) and in the empty form (unloaded/NE). Subsequently, the mentioned nanomaterials were characterized by the measurement of dynamic light scattering (DLS). The MB/NE and unloaded/NE showed appropriate physical and chemical characteristics, with particle size ≤ 200 nm, polydispersity index close to 0.3, and zeta potential exhibiting negative charge, showing stable values during the analysis. The incorporation of the MB did not cause changes in the photophysical profile of the photosensitizer. The quantification performed showed an incorporation rate of 81.9%. Viability studies showed an absence of cytotoxicity for MB/NE in the concentrations of 10-75 µmol·L-1, free MB at the concentration of 75 µmol·L-1, and unloaded NE 47.5% (v/v), presenting viability close to 90%, respectively. PDT in vitro protocols applied to OSCC and HeLa cells showed a decrease in cell viability through only one irradiation, evidencing the photodynamic activity of the formulation when applied to cancer cells. The results obtained were superior to those found in the literature where they use free MB, showing that the association between nanotechnology and PDT optimizes the proposed protocol. From the results obtained, it is possible to indicate that the NE have high stability, with satisfactory physical-chemical parameters, in addition to not presenting cytotoxicity in the tested concentrations, showing their in vitro biocompatibility, in addition to presenting satisfactory effects when combined MB/NE with PDT, showing the potential of MB/NE as a very promising nanostructured photosensitizer for the treatment of some types of cancer.

Artificial Intelligence-Based Bolt Loosening Diagnosis Using Deep Learning Algorithms for Laser Ultrasonic Wave Propagation Data.

The application of deep learning (DL) algorithms to non-destructive evaluation (NDE) is now becoming one of the most attractive topics in this field. As a contribution to such research, this study aims to investigate the application of DL algorithms for detecting and estimating the looseness in bolted joints using a laser ultrasonic technique. This research was conducted based on a hypothesis regarding the relationship between the true contact area of the bolt head-plate and the guided wave energy lost while the ultrasonic waves pass through it. First, a Q-switched Nd:YAG pulsed laser and an acoustic emission sensor were used as exciting and sensing ultrasonic signals, respectively. Then, a 3D full-field ultrasonic data set was created using an ultrasonic wave propagation imaging (UWPI) process, after which several signal processing techniques were applied to generate the processed data. By using a deep convolutional neural network (DCNN) with a VGG-like architecture based regression model, the estimated error was calculated to compare the performance of a DCNN on different processed data set. The proposed approach was also compared with a K-nearest neighbor, support vector regression, and deep artificial neural network for regression to demonstrate its robustness. Consequently, it was found that the proposed approach shows potential for the incorporation of laser-generated ultrasound and DL algorithms. In addition, the signal processing technique has been shown to have an important impact on the DL performance for automatic looseness estimation.

Gamma Radiation-Induced Effects over an Optical Fiber Laser: Towards New Sensing Applications.

In the present work, the effect of gamma radiation on the performance of different types of erbium-doped fibers (EDFs) when they are used in a fiber ring cavity (FRC) configuration is studied. Several pieces of commercial EDF are gamma-ray irradiated with different doses to evaluate the output power variations over time. The influence of different doses, from 150 Gy to 1000 Gy, over the output power level measurement and their amplified spontaneous emission (ASE) are experimentally evaluated both in the C and L bands. By using an FRC configuration we can detect the presence of gamma radiation. We can also estimate the irradiation doses applied to EDFs by measuring the slope of the short-term emission power.

The advantages of carbon dioxide laser applications in paediatric oral surgery. A prospective cohort study.

The aim of this study is to evaluate and demonstrate the advantages of the carbon dioxide laser in paediatric oral surgery patients in terms of less post-operative complications, healing without scaring, functional benefits, positive patient perception and acceptance of the treatment. One hundred fit and healthy paediatric patients (aged 4-15 years) were recruited to undergo laser surgery for different soft tissue conditions. The outcome of these laser treatments was examined. The Wong-Baker Faces Pain Rating Scale was employed to evaluate the pain before, immediately after laser treatment in the clinic and 1 day after post-operatively at home. Post-operative complications and patients' perception and satisfaction were self-reported during a review telephone call the day after treatment. The patients were reviewed 2 weeks after surgery. Laser parameter was 1.62 W, measured by power meter, continuous wave mode with 50 % emission cycle. The beam spot size at the target tissue was 0.8 mm. The pain score pre-operative, during and immediately after laser treatment was rated 0. Whilst the pain score 1 day after surgery was rated between 0 and 2, the healing time was measured over 2 weeks. None of the patients reported post-operative complications after surgery. Patients' perception and acceptance were rated very good. Laser dentistry is a promising field in modern minimally invasive dentistry, which enables provision of better care for children and adolescents. In this cohort study, the use of the carbon dioxide laser therapy offers a desirable, acceptable and minimally invasive technique in the surgical management of soft tissues in paediatric oral surgery with minimal post-operative complications.

Direct spectral analysis and determination of high content of carcinogenic bromine in bread using UV pulsed laser induced breakdown spectroscopy.

Laser induced breakdown spectroscopy (LIBS) was applied for the detection of carcinogenic elements like bromine in four representative brands of loaf bread samples and the measured bromine concentrations were 352, 157, 451, and 311 ppm, using Br I (827.2 nm) atomic transition line as the finger print atomic transition. Our LIBS system is equipped with a pulsed laser of wavelength 266 nm with energy 25 mJ pulse(-1), 8 ns pulse duration, 20 Hz repetition rate, and a gated ICCD camera. The LIBS system was calibrated with the standards of known concentrations in the sample (bread) matrix and such plot is linear in 20-500 ppm range. The capability of our system in terms of limit of detection and relative accuracy with respect to the standard inductively coupled plasma mass spectrometry (ICPMS) technique was evaluated and these values were 5.09 ppm and 0.01-0.05, respectively, which ensures the applicability of our system for Br trace level detection, and LIBS results are in excellent agreement with that of ICPMS results.

An endoscopic approach providing near-infrared laser-induced coagulation with accurate depth limits.

This article investigates an endoscopic approach that utilizes negative pressure to achieve laser-induced thermal coagulation limited to the esophageal wall's mucosal and superficial submucosal layers. The study was built upon a series of studies combining numerical simulation based on the Monte-Carlo technique and ex vivo porcine tissue experiments, including apparatus design and histology analysis. An endoscopy apparatus was developed using 3D printing to validate the tissue stretching-based approach. A fiber-pigtailed diode was used as the near-infrared source, emitting 208.8 W/cm2 laser irradiance at 1.5 µm. Simulation results suggested that the approach successfully created a local heat well to prevent residual thermal effects (>65°C) from penetrating the deeper submucosal layer. Histology analysis of ex vivo tissues showed that at a fluence of 5.22 kJ/cm2, the depth of thermal coagulation was reduced by half compared to the control. With further preclinical studies, including endoscopy apparatus design, the approach can be applied to the larger esophageal surface.

Occlusio Pupillae: A Duet of Darkness Where the Patient Sees Naught, and the Doctor Discerns Not.

A 71-year-old, one-eyed female patient presented with a loss of vision in the right eye due to trauma 20 years ago and a progressive diminution of vision in the left eye over the past six years. An ambiguous history of some surgery performed on the left eye was elicited, with no available records, adding an element of uncertainty to this case. Visual acuity (VA) was noted as no light perception (No PL) in the right eye and light perception with accurate projection of rays (PL+, PR accurate) in the left eye. Anterior segment slit-lamp evaluation of the right eye showed a shrunken globe with low intraocular pressure (IOP). The left eye exhibited signs of chronic uveitis with occlusio pupillae, non-visualization of the lens, and a doubtful conjunctival bleb with scleral thinning superior to the limbus. B-scan evaluation was suggestive of phthisis in the right eye and an equivocal lens shadow in the left eye. A yttrium aluminum garnet (YAG) pupillary membranotomy was planned for the left eye under steroid cover and was cautiously attempted, successfully detaching the occlusio membrane and revealing an underlying complicated cataract beneath it. Post-laser, medical management included topical anti-glaucoma and steroid medications, along with systemic steroids. The VA improved from PL+, PR accurate to 3/60 (improving to 6/60 with a Retinal Acuity Meter). After stabilization of the uveitis over the next few weeks and under a steroid cover, a temporal clear-corneal phacoemulsification was cautiously performed with intra-operative management of the small pupil, and a hydrophobic lens was implanted. At one month post-surgery, the patient's best-corrected visual acuity had improved to 6/12 for distance and N6 for near. This report highlights a compelling instance wherein the neodymium:Yttrium-aluminum-garnet (Nd:YAG) laser was efficaciously employed for a lesser-known application in resolving a diagnostic dilemma and for instituting an interim treatment strategy in a challenging case involving a one-eyed patient prior to planning a definitive surgery. This case emphasizes the importance of thinking out of the box, ensuring comprehensive preoperative and careful intra-operative precautions in the management of patients diagnosed with complex ocular inflammatory conditions, so as to optimize visual outcomes, eventually resulting in achieving a gratifying reduction of visual disability and improvement of quality of life.

Lasers efficacy in pain management after primary and secondary endodontic treatment: a systematic review and meta-analysis of randomized clinical trials.

Postoperative pain is a common concern following root canal treatments (RCT), impacting both patients and oral health practitioners. This systematic review and meta-analysis aimed to evaluate the effectiveness of laser treatment modalities in reducing postoperative pain compared to conventional methods after primary and secondary RCT in permanent mature teeth. A search of three electronic databases (PubMed, ScienceDirect, and The Cochrane Library) was conducted, using a broad range of keywords and terms. Gray literature and manual searches were conducted to complement the search. The inclusion criteria included randomized clinical trials based on the objective of the secondary study. A minimum sample size of 10 participants per group and a clearly defined criterion for postoperative pain assessment were required. The characteristics of the included studies were presented as tables. The Cochrane collaboration tool RoB 2.0 was used to assess the risk of bias within each study. Two reviewers extracted the data and assessed the studies independently, and discrepancies were resolved through consultation with a third reviewer. A random-effects model was employed for meta-analysis to estimate the overall effect measure. Heterogeneity was evaluated using Cochran's Q test and the I2 index. Publication bias was explored via Funnel plots and Egger's test. Subgroup analyses and meta-regression were conducted to assess variations among laser methods and examine the influence of independent factors. The significance threshold for all analyses was set at 5% (α = 0.05). Intraoral laser therapy demonstrated no significant advantage over conventional treatments but consistently outperformed placebo, particularly from 4 to 72 h post-treatment. Low-level laser therapy provided slight pain reduction in the first 8 h, though its effectiveness diminished in retreatment scenarios. Photodynamic therapy and laser disinfection showed marginal benefits, especially shortly after treatment, with reduced efficacy in longer-term or retreatment contexts. Further research is needed to explore different applications of laser modalities and assess distinct prognostic factors in more detail.

Germanate glass for laser applications in ∼ 2.1 µm spectral region: A review.

The growing landscape of laser applications in ∼ 2 µm spectral region leads to the development of novel transparent media that provide low attenuation solutions for high power laser applications. This includes investigating glassy media such as heavy metal oxides (e.g. tellurite and germanate), fluoride and chalcogenides as an alternative to the most efficient and widely utilized silica glass. This review article discusses the potential of a heavy metal oxide lead-germanate glass (GeO2-PbO-Ga2O3-Na2O) for ∼ 2.1 µm laser applications, with a focus on our contribution to the field. Firstly, a comparative study of commercially available silicates and fluorides with germanate glass is presented to reveal germanate to be a favorable material for 2.1 µm laser applications. Secondly, as our contribution to the field, we present the development of the first ∼ 2.1 µm small cavity single frequency laser action in a Ho3+ doped GPGN glass that verifies its capability for ∼ 2 µm laser applications and beyond.

Virtual scale function of gastrointestinal endoscopy for accurate polyp size estimation in real-time: a preliminary study.

SIGNIFICANCE: Polyp size is important for selecting the surveillance interval or treatment policy. Nevertheless, it is challenging to accurately estimate the polyp size during endoscopy. An easy and cost-effective function to assist in polyp size estimation is required. AIM: To propose a virtual scale function for endoscopy and evaluate its performance and expected accuracy. APPROACH: An adaptive virtual scale behavior was demonstrated. The measurement error of the virtual scale along the distance between the tip of the endoscope and the object plane was evaluated using graph paper. The accuracy of polyp size estimation by an expert endoscopist was compared with the accuracy of the biopsy forceps method using phantom images. RESULTS: The measurement errors of the virtual scale were ≤ 0.7 mm when the distance to the graph paper, which faced the tip of the endoscope, varied from 4 to 30 mm. The accuracy with the virtual scale was significantly higher than that obtained with biopsy forceps (5.3 ± 5.5 % versus 11.9 ± 9.4 % , P < 0.001). CONCLUSIONS: The virtual scale function, which operates in real-time without any additional device, can be used to estimate polyp sizes easily and accurately with endoscopy.

Photobiomodulation Therapy vs. Corticosteroid for the Management of Erosive/Ulcerative and Painful Oral Lichen Planus. Assessment of Success Rate during One-Year Follow-Up: A Retrospective Study.

Photobiomodulation (PBM) therapy is a promising approach for the management of inflammatory conditions and autoimmune lesions, such as oral lichen planus (OLP). The aim of this retrospective study was to assess the effectiveness of PBM in the management of painful and erosive/ulcerative OLP and to compare it with the standard of care that is the topical application of corticosteroids. 96 patients were included with erosive and painful OLP. 48 patients received PBM therapy and 48 received corticosteroids. Data was collected retrospectively on pain using the visual analogue scale; clinical aspects of lesions were assessed with the REU score, and the recurrence rate was noted. One session of PBM therapy with a helium-neon red light (635 nm) was carried out every 48 h for 6 weeks. Treatments were mainly made in contact mode, using a fiber with a diameter of 600 µm (0.6 mm). The output power of the laser beam was calibrated by a power meter. A delivered power of 0.1 W was used for 40 s in a continuous wave (CW), corresponding to a delivered energy of 4 J. The delivered energy density related to the fiber diameter was 1415 J/cm2. Each treated point was considered as 1 cm2 of diameter. PBM therapy within these parameters was carried out on each point until the totality of the lesion was covered, including the non-erosive OLP area. Furthermore, healthy mucosa within 5 mm of the lesion was also irradiated with the same conditions. This PBM treatment was performed during 6 consecutive weeks. The topical corticosteroid treatment consisted of cortisone application to cover the OLP 3 times/day for 6 weeks. Follow-up was made at 6 weeks and at 3, 6 and 12 months. After 6 weeks, both groups showed complete absence of pain, and a complete disappearance of ulcerative/erosive areas. No significant difference was found for both groups concerning the recurrence rate of erosive OLP during the follow-up period; values were 0% at 6 weeks for both groups and 79% and 87.5% for the corticosteroid and PBM group, respectively, at 12 months of follow-up. PBM is effective for managing OLP and is significantly similar to topical corticosteroids without any need for the use of medication and with no reported side effects.

Image-guided adaptive radiation therapy (IGART): Radiobiological and dose escalation considerations for localized carcinoma of the prostate.

The goal of this work was to evaluate the efficacy of various image-guided adaptive radiation therapy (IGART) techniques to deliver and escalate dose to the prostate in the presence of geometric uncertainties. Five prostate patients with 15-16 treatment CT studies each were retrospectively analyzed. All patients were planned with an 18 MV, six-field conformal technique with a 10 mm margin size and an initial prescription of 70 Gy in 35 fractions. The adaptive strategy employed in this work for patient-specific dose escalation was to increase the prescription dose in 2 Gy-per-fraction increments until the rectum normal tissue complication probability (NTCP) reached a level equal to that of the nominal plan NTCP (i.e., iso-NTCP dose escalation). The various target localization techniques simulated were: (1) daily laser-guided alignment to skin tattoo marks that represents treatment without image-guidance, (2) alignment to bony landmarks with daily portal images, and (3) alignment to the clinical target volume (CTV) with daily CT images. Techniques (1) and (3) were resimulated with a reduced margin size of 5 mm to investigate further dose escalation. When delivering the original clinical prescription dose of 70 Gy in 35 fractions, the "CTV registration" technique yielded the highest tumor control probability (TCP) most frequently, followed by the "bone registration" and "tattoo registration" techniques. However, the differences in TCP among the three techniques were minor when the margin size was 10 mm (⩽1.1%). Reducing the margin size to 5 mm significantly degraded the TCP values of the "tattoo registration" technique in two of the five patients, where a large difference was found compared to the other techniques (⩽11.8%). The "CTV registration" technique, however, did maintain similar TCP values compared to their 10 mm margin counterpart. In terms of normal tissue sparing, the technique producing the lowest NTCP varied from patient to patient. Reducing the margin size seemed the only sure way to reduce the NTCP significantly, irrespective of the IGART technique employed. In escalating the dose with the iso-NTCP constraint, the largest average gain in dose was observed with the "tattoo registration" technique, followed by the "CTV registration" and "bone registration" techniques. This is attributed to the fact that in three of the five patients, the "tattoo registration" technique yielded the lowest NTCP, hence a greater window of opportunity to escalate the dose was possible with this technique. However, the variation among the five patients was also largest with the "tattoo registration" technique where, in the case of one patient, the required dose actually needed to be below the original prescription dose of 70 Gy to satisfy the iso-NTCP constraint. This was not the case with the "CTV registration" technique where positive and similar dose escalation was allowed on all five patients. Based on these data, an attractive dose escalation strategy may be to implement the "CTV registration" technique (for consistent dosimetric coverage) for daily target localization in combination with a margin reduction (for increased normal tissue sparing).