980-nm Diode Laser Research Articles

Comparative evaluation of Indocyanine Green and 810nm Diode Laser Assisted Antimicrobial Photodynamic Therapy with 810nm Diode Laser Assisted New Attachment Procedure as adjuncts to Scaling and Root Planning in Supportive Periodontal Therapy: A Randomized Controlled Split-Mouth Clinical Trial

BACKGROUND: Minimally invasive nonsurgical management of recurrent periodontal pockets remains the most viable option during supportive periodontal therapy (SPT), but with inconclusive results. The purpose of this study is to evaluate and compare the adjunctive use of Indocyanine green (ICG) and 810nm Diode laser assisted photodynamic therapy (IG-PDT) with 810nm Diode laser assisted new attachment procedure (LANAP) in the management of persistent pockets in SPT. MATERIALS AND METHODS: This single blinded randomized controlled split mouth clinical trial included 20 participants with at least two adjacent teeth with PPD ≥5mm and Clinical attachment level (CAL) ≥3mm in the contralateral quadrants. IG-PDT group received application of 5mg/ml solution of ICG for one minute followed by 810±10nm diode laser with 1W power density. LANAP group received 810±10nm diode laser application at 3W power density with 100ms and 650ms pulse duration at two consecutive passes. Clinical parameters i.e., Plaque index (PI), Gingival index (GI), PPD, CAL gain were recorded at baseline, 3 and 6 months. Landry’s Healing index was assessed on the 7th day and 1 month postoperatively. Patient comfort was assessed using Visual Analog Scale (VAS) immediate post-operatively. RESULTS: Student t test and repeated measures of ANOVA were used for statistical analysis. Both site level and patient level assessments of clinical parameters showed improvement in clinical parameters in both groups. However, IG-PDT group showed significantly greater improvements in PPD (<0.001) and CAL (<0.001) at 3 and 6 months evaluation. IG-PDT showed better healing (P-0.03) at 7th post-operative day. However, LANAP showed less discomfort (2.40±0.50) compared to IG-PDT group (3.20±0.61). CONCLUSION: IG-PDT is shown to provide better clinical outcomes compared to LANAP in management of patients under SPT.

The Effectiveness of Photobiomodulation Using 940-nm Diode Laser for Reducing Pain, Swelling and Trismus After Third Molar Surgery: A Single-Blinded Randomized Control Trial

The Effectiveness of Photobiomodulation Using 940-nm Diode Laser for Reducing Pain, Swelling and Trismus After Third Molar Surgery: A Single-Blinded Randomized Control Trial

Quantitative photothermal analysis and multispectral imaging of dental structures: insights into optical and thermal properties of carious and healthy teeth.

In the analysis of two-layered turbid dental tissues, the outer finite-thickness layer is modeled by an optical transport coefficient distinct from its underlying semi-infinite substrate layer. The optical and thermophysical parameters of healthy and carious teeth across the various wavelengths were measured leading to the determination of the degree of reliability of each of the fitted parameters, with most reliable being thermal diffusivity and conductivity, enamel thickness, and optical transport coefficient of the enamel layer. Quantitative pixel-by-pixel images of the key reliable optical and thermophysical parameters were constructed. We introduced a theoretical model of pulsed photothermal radiometry based on conduction-radiation theory and applied to quantitative photothermal detection and imaging of biomaterials. The theoretical model integrates a combination of inverse Fourier transformation techniques, avoiding the conventional cumbersome analytical Laplace transform method. Two dental samples were selected for analysis: the first sample featured controlled, artificially induced early caries on a healthy tooth surface, while the second sample exhibited natural defects along with an internal filling. Using an Nd:YAG laser and specific optical parametric oscillator (OPO) wavelengths (675, 700, 750, and 808nm), photothermal transient signals were captured from different points on these teeth and analyzed as a function of OPO wavelength. Measurements were also performed with an 808-nm laser diode for comparison with the same OPO wavelength excitation, particularly for the second sample with natural defects. The findings demonstrated that the photothermal transient signals exhibit a fast-decaying pattern at shorter wavelengths due to their higher scattering nature, while increased scattering and absorption in the carious regions masked conductive and radiative contributions from the underlayer. These observations were cross-validated using micro-computed tomography, which also enabled the examination of signal patterns at different tooth locations. The results of our study showed the impact of optical and thermal characteristics of two-layered turbid dental tissues via an inverse Fourier technique, as well as the interactions between these layers, on the patterns observed in depth profiles.

Antibacterial effect of red laser-activated silver nanoparticles synthesized with grape seed extract against Staphylococcus aureus and Escherichia coli.

Living organisms, particularly humans, frequently encounter microorganisms such as bacteria, fungi, and viruses in their surroundings. Silver nanoparticles are widely used in biomedical devices because of their antibacterial and antiviral properties. The study evaluates the efficacy of red laser and silver nanoparticles from grape seed extract (AgNPs-GSE) in reducing Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacteria, which cause infections. The sample comprised three groups: a control group without laser irradiation (T0), Escherichia coli samples (A1 and A2) irradiated with a 405-nm diode laser at different times and concentrations of silver nanoparticles, and Staphylococcus aureus samples (A3 and A4) illuminated with a 405-nm diode laser at different times and concentrations. Bacteria in groups A2 and A4 were treated with a photosensitizer (PS) made from grape seed extracts, incubated for 10min, and then irradiated for 90, 120, 150, and 180s. The samples were cultured on TSA media, set at 37°C, counted using a Quebec colony counter, and analyzed using ANOVA and Tukey tests with a significance level of p < 0.05. The study illustrated that the combination of 10µl of AgNPs-GSE, exposure to a red laser at 405nm, and an energy density of 3.44J/cm2 effectively photoinactivated both Escherichia coli and Staphylococcus aureus bacteria. For Escherichia coli bacteria irradiated for 180s with concentrations of 1mM, 1.5mM, and 2mM AgNPs-GSE, bacterial viability decreased by 64.50%, 70.74%, and 79.53%, respectively. Similarly, Staphylococcus aureus bacteria, subjected to irradiation for 180s with concentrations of 1mM, 1.5mM, and 2mM AgNPs-GSE, demonstrated reductions in bacterial viability by 70.23%, 73.47%, and 85.04%, respectively. The findings from the present study indicate that at an energy density of 3.44J/cm2, it was possible to inactivate Escherichia coli by 79.53% and Staphylococcus aureus by 85.04%.

In vitro study: methylene blue-based antibacterial photodynamic inactivation of Pseudomonas aeruginosa

Pseudomonas aeruginosa is one of the most antibiotic-resistant and opportunistic pathogens in immunocompromised and debilitated patients. It is considered the cause of most severe skin infections and is frequently found in hospital burn units. Due to its high antibiotic resistance, eliminating P. aeruginosa from skin infections is quite challenging. Therefore, this study aims to assess the novel in vitro antibacterial activity of methylene blue using a 635-nm diode laser to determine the effective power and energy densities for inhibition of P. aeruginosa. The strain was treated with various concentrations of methylene blue and 635-nm diode laser at powers of 300 mW/cm2 and 250 mW/cm2. The diode laser’s potency in the photo-destruction of methylene blue and its degradation through P. aeruginosa were also evaluated. Colony-forming unit (CFU)/ml, fluorescence spectroscopy, optical density, and confocal microscopy were used to measure the bacterial killing effect. As a result, the significant decrease of P. aeruginosa was 2.15-log10, 2.71-log10, and 3.48-log10 at 60, 75, and 90 J/cm2 after excitation of MB for 240, 300, and 360 s at a power of 250 mW/cm2, respectively. However, a maximum decrease in CFU was observed by 2.54-log10 at 72 J/cm2 and 4.32-log10 at 90 and 108 J/cm2 after 300 mW/cm2 of irradiation. Fluorescence images confirmed the elimination of bacteria and showed a high degree of photo-destruction compared to treatment with methylene blue and light alone. In conclusion, MB-induced aPDT demonstrated high efficacy, which could be a potential approach against drug-resistant pathogenic bacteria.Key points• Combination of methylene blue with 635-nm diode laser for antibacterial activity.• Methylene blue photosensitizer is employed as an alternative to antibiotics.• aPDT showed promising antibacterial activity against Pseudomonas aeruginosa.

Treatment of Recurrent Aphthous Stomatitis with 940nm Diode Laser

Background &amp; objectives: Ulcers in the mouth (recurrent aphthous stomatitis) are very common and may vary in size from very small to very large. The exact cause of mouth ulcers isn’t known but acidic foods and stress are thought to be factors, as well as local traumatic damage such as that caused vigorous toothbrushing. Although uncomfortable, small ulcers are tolerable, but large ulcers can last for up to 2 weeks and greatly affect the ability to eat, drink and even talk. This study aimed to evaluate the efficacy of treatment of recurrent aphthous stomatitis by application of 940 nm diode laser irradiation &amp; its effect on the duration and pain sensation. Materials and methods: A total number of 32 patients having at least 2 ulcers for each. Those patients were enrolled in this study using a split mouth design. The study included two groups, The experimental (study group) consisted of thirty two ulcers ( in the 32 patients ) were subjected to 940 nm laser irradiation &amp; control group comprised of thirty two ulcers ( in the same 32 patients ) left without laser irradiation. Pain scores were recorded before and after laser treatment. The patient subjected to follow-up visits until complete healing of the ulcers occurred. Results: There were immediate changes in the pain scores of the experimental group just after diode laser application. The duration of the control group lesions ranged between (7-14) days, while the lesion in the experimental group subsided with a range between (4-12) days. Conclusion: 1.Single session of diode laser irradiation can be used to produceimmediate, dramatic and sustained analgesic effect on RAS lesion.2.The lesion duration was significantly reduced to about 40%from that of control lesion.

Clinical Application of Long-Pulsed 800-Nm Diode Laser Depilation Technology on Microtia Reconstruction in 965 Patients.

The issue of hair growth on reconstructed ears has been a matter of concern for both patients and surgeons, despite the notable progress made in microtia reconstruction technology in recent times. This study aims to present the practical implementation of long-pulsed 800-nm diode laser depilation technology in the field of auricular reconstruction. Furthermore, it seeks to establish a comprehensive and standardized protocol for utilizing lasers in the reconstruction of microtia ears. A total of 965 patients (comprising 1021 ears) diagnosed with congenital microtia underwent treatment using 800-nm long-pulsed diode laser depilation. The participants received 1-3 treatment sessions with intervals of 25-30days. To assess the effectiveness of the treatment, two independent observers compared photographs and measured the reduction in terminal hair count before and after the final session. Clinical outcomes were evaluated using VAS questionnaires, and any adverse events were diligently recorded. The findings indicated that the utilization of the long-pulsed 800-nm diode laser was both safe and efficient in achieving hair removal during microtia ear reconstruction. As additional sessions were conducted, pain scores demonstrated a decline, while adverse reactions remained minimal. This is a retrospective single-institution study. The application of a long-pulsed 800-nm diode laser has been proved to be a safe and effective method for removing hair during the process of microtia ear reconstruction, involving the use of a tissue expander and autologous costal cartilage. To achieve satisfactory results in hair removal, it was found necessary to repeat the shots procedure two to three times. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Er,Cr:YSGG and 980nm diode lasers influence dentin surface volume after cariogenic challenge: in vitro study.

This study aimed to evaluate the influence of the Er,Cr:YSGG irradiation and 980-nm diode lasers on the surface roughness (SR) and volume loss (VL) of dentin subjected to cariogenic challenge. Subsequently, 130 specimens of bovine dentin were divided into the following 13 groups: NT: no treatment; FG: fluoride gel; FV: fluoride varnish; Di: 980-nm diode; Di + FG; Di + FV; FG + D; FV + Di; Er: Er,Cr:YSGG; Er + FG; Er + FV; FG + Er and FV + Er. Er,Cr:YSGG laser parameters were as follows: 0.25 W; 5.0 Hz; 4.46 J/cm2 without water and 55% air. Furthermore, the 980-nm diode laser parameters were 2.0 W; 2.0 Hz; 21.41 J/cm2. The samples from each group were subjected to pH cycling. A confocal laser scanning microscope was used to evaluate SR and VL. Difference between the volume of the reference and treated areas + DES/RE was used to determine SR and VL. The mean values of the different groups were subjected to analysis of variance and Tukey's post-hoc test. The VL values were analyzed using the Kruskal-Wallis and Dunn post-hoc test (p < 0.05). The SR of the reference area did not show a statistically significant 1807-3107-bor-38-e025treatment and cariogenic challenge (p > 0.05). Moreover, VL in the FV + Di and FV + Er groups showed a statistically significant difference compared with areas submitted to different types of treatment and cariogenic challenge (p > 0.05). Er,Cr:YSGG and 980-nm diode lasers associated with fluoride varnishes decreased dentin VL in bovine teeth submitted to cariogenic challenge.

Comparative evaluation of thermal impact of 980nm diode laser on soft tissue using irrigation and non-irrigation systems: A histomorphometric study.

Diode laser is one of the most captivating technologies in dental practice. In periodontics, when used at appropriate settings, it possesses the best properties for selective surgical and nonsurgical procedures such as subgingival calculus removal without a thermal change of the root surface, and also provides tissue surface sterilization. However, lasers always produce a certain amount of thermal damage to the soft tissues. Therefore, this study aimed to comparatively evaluate the thermal impact of 980-nm diode laser incisions, when used with irrigation versus nonirrigation systems. The study was conducted on 24 gingival tissue samples obtained from the goat's mandible and maxilla. The samples were divided into two groups of 12 samples each, and laser incisions were given in 4 power settings, using 980-nm diode laser in super short pulse mode, with and without saline irrigation. Martius Scarlet Blue staining technique was used to prepare the histological slides. Then, slides were examined under a research microscope (Olympus CX 21), and the pictures of the slides were taken by mounting the camera onto the microscope mobile mount. The microscopic images hence obtained were analyzed for the depth and width of the incisions, area of carbonization, necrosis, and reversible damage, using the Digimizer image analysis software. The results of this study demonstrated that the mean incision depth was higher (592.49 ± 180.97, P < 0.05), with less carbonization (25.52 ± 29.21, P = 0.00) and less necrosis (311.63 ± 156.441, P < 0.05) in the laser incisions with irrigation, as compared to the laser incisions given without irrigation system. Within the limitations of this study, it can be concluded that using an irrigation system causes less collateral damage while maintaining the incising efficiency of the diode laser. Further studies with a higher sample size, controlled irrigation systems, and incision techniques are needed to evaluate the efficiency of diode lasers for the clinical explanation of the results.

Experience with 808-nm diode laser in the treatment of 47 cases of oral vascular anomalies.

Treatment of oral vascular anomalies (OVA) has focused on minimally invasive techniques rather than radical surgery. We investigated the efficacy and safety of diode laser using the photocoagulation technique in the management of OVA. Forty-seven subjects with OVA were treated with forced dehydration with induced photocoagulation (FDIP) using diode laser (808 nm/4.5 W). This series consisted mostly of male (63.8%) and non-white (63.8%) patients with a mean age of 57.4 years. Varices (91.5%), venous malformations (6.4%), and hemangiomas (2.1%) with a mean size of 7.1 (±4.9) mm were the conditions treated. OVA presented as a nodular lesion (63.8%) involving mainly the lower lip (46.8%). Pulsed laser mode was used as standard and the number of applications varied from one to four sessions, with the majority requiring only one (83%) FDIP session. Kaplan-Meier analysis revealed that complete clinical healing can occur on the 15th day (n=9/29.5%), followed by the 20th (n=6/45.5%), and 30th (n=7/70.5%) days. Postoperative edema was observed in 31 (66%) patients, and recurrence of the lesion occurred in two (4.2%). Based on the data on complete clinical healing, minimal patient discomfort, and satisfactory esthetic results, we can confirm that FDIP by diode laser is a promising candidate for the safe and efficacious treatment of OVA.

Long-term outcomes of modified transcanalicular diode laser dacryocystorhinostomy.

The purpose of this study is to assess the long-term outcomes of modified transcanalicular diode laser dacryocystorhinostomy in a large cohort of patients affected by primary acquired nasolacrimal duct obstruction. This study, conducted from January 17 to June 2022, encompassed 141 patients (159 procedures) who underwent modified transcanalicular diode laser dacryocystorhinostomy (MT-DCR). The procedure employed an 810-nm diode laser. Patients were monitored for at least a year after the intervention. Anatomical success was determined by ostium patency upon irrigation, while functional success referred to epiphora resolution. Parameters studied included patient demographics, procedure duration, complications, and both anatomical and functional success. Statistical analysis was performed using the Statistical Package for the Social Sciences software, with results considered significant at a 95% confidence interval (p≤0.05). A total of 159 lacrimal drainage systems (141 patients: 112 women and 29 men) were included in this study. Among them, 18 underwent bilateral procedures. The average patient age was 58 years (range: 34-91 years), and the average surgical duration was 24 minutes (range: 18-35 minutes). One year after the surgery, MT-DCR exhibited anatomical and functional success rates of 84.9% (135/159) and 83% (132/159), respectively. MT-DCR achieved an anatomical success rate of 84.9%, reflecting an excellent outcome. However, further extensive studies with larger sample sizes and longer follow-up periods are necessary to substantiate these findings.

Antibacterial Efficacy of Diode laser 810nm on Enterococcus Faecalis on Primary Teeth, an invitro study

Antibacterial Efficacy of Diode laser 810nm on Enterococcus Faecalis on Primary Teeth, an invitro study

Antibacterial effectiveness of different final irrigation activation techniques.

Background and objective: To evaluate and compare the antibacterial effectiveness of ultrasonic, diode laser, XP endo finisher and finisher gentle file brush against Enterococcus faecalis in root canal dentin. Methods: Fifty-five single-rooted extracted mandibular premolars were decoronated to have a length of 12 mm, instrumented biomechanically with protaper Next up to size X3. After sterilization, five roots were selected as negative controls and the remaining teeth were inoculated with E. faecalis and incubated for 48 hr and at 37 ºC. The roots were then randomly divided into five groups (n=10), GI: Control group, GII: 5.25% NaOCl irrigation was activated by the ultrasonic system , GIII: By 980-nm diode laser , GIV: By Xp-endo finisher and GV : Activated by Finisher gentle file-brush. The antimicrobial efficacy was tested by collecting transfer fluid saline from the canals and counting the colony forming units (CFUs) of viable E. faecalis on agar plates. The statistical calculations were performed in JMP pro 14.3.0. using Analysis of Variance (ANOVA) followed by a Tukey test to define the differences between the tested groups. Result: The mean bacterial CFU were 10.6 X 10^7 for Finisher gentle file brush, 35.6×10^7 for Diode laser, 39.6×10^7 for ultrasonic and 42.3×10^7 for XP Endo Finisher. Finisher gentle file brush showed a significant reduction in the colony count compared to the other groups. Conclusion: None of the irrigation activation techniques removed the bacteria completely from the canal. The four tested irrigation activation techniques were shown to be effective in the disinfection of the E. faecalis-contaminated root canals. Finisher gentle file brush was the most effective against E. faecalis, while XP endo finisher was the least effective against E. faecalis. treatment against E. faecalis in the root canal. Keywords: Utrasonic, Diode laser, XP endo finisher, irrigation activation techniques

Comparative analysis of the safety and efficacy of 1470-nm diode laser enucleation of the prostate and plasmakinetic resection of prostate in the treatment of large volume benign prostatic hyperplasia (>80 ml)

Objective To compare the efficacy and safety of 1470-nm diode laser enucleation of the prostate (DiLEP) with that of plasmakinetic resection of the prostate (PKRP) in treating patients with large benign prostatic hyperplasia (BPH > 80ml). Methods The clinical data from 211 cases of BPH (>80 ml) were collected for analysis. The patients were divided into two groups: the PKRP group (n = 118) and the DiLEP group (n = 93), based on the surgical method used. Result The DiLEP group demonstrated significantly lower surgical time (p < 0.001), intraoperative bleeding (p < 0.001), bladder flushing time (p = 0.003), indwelling catheter time (p < 0.005), and length of hospital stay (p = 0.018) compared to the PKRP group. However, the quality of the prostatectomy was significantly higher in the DiLEP group (p = 0.005). The Qmax for the DiLEP group was significantly higher than that of the PKRP group (p < 0.05). Compared to the PKRP group, the incidence of urinary incontinence in the DiLEP group increased significantly 4 weeks post-surgery (p = 0.026), although the need for blood transfusion during surgery was significantly reduced (p = 0.037). Conclusion Both DiLEP and PKRP are safe and effective methods for treating large-volume BPH. However, DiLEP offers advantages such as more thorough glandular resection, shorter surgical time, reduced bleeding, quicker recovery, and fewer complications.

Effect of Nd:YAG and 980nm Diode laser irradiation as a hypersensitivity treatment on shear bond strength of metal orthodontic brackets to enamel

Lasers are one of the tooth hypersensitivity treatments. This study aimed to determine the effect of irradiation of Nd:YAG 1064nm and 980nm Diode lasers, used for hypersensitivity treatment, on the shear bond strength (SBS) of metal orthodontic brackets to enamel. Ethylenediaminetetraacetic acid (EDTA) was used to simulate sensitivity in 70 extracted human premolars. The teeth were radiated with 1w Nd:YAG, 1.5w Nd:YAG, 1w Diode, or 1.5w Diode. All samples were incubated at 37° for 24 hours, after bonding the metal brackets. SBS values and adhesive remnant index (ARI) for each tooth was recorded. One-way analysis of variance (ANOVA) and Kruskal-Wallis test were used to compare the mean SBS and the distribution of ARI scores between the study groups, respectively. The SBS mean from the highest to the lowest were in 1w Diode (25.71Mpa), 1w Nd:YAG (24.66Mpa), 1.5w Diode (23.08Mpa), control (21.68Mpa) and 1.5w Nd:YAG (21.53Mpa) groups. No statistically significant difference existed between different groups, in terms of SBS (p=0.211) and ARI distribution (p=0.066). The application of Nd:YAG and 980nm Diode lasers to treat tooth hypersensitivity did not change the SBS of metal orthodontic brackets to the enamel and thus, are harmless to use for orthodontic patients.

Association of active oxygen-releasing gel and photodynamic therapy in the treatment of residual periodontal pockets in type 2 diabetic patients: A randomized controlled clinical study.

The aim of this study was to evaluate the effect of active oxygen-releasing gel as an adjuvant, with and without antimicrobial photodynamic therapy (aPDT), in the treatment of residual pockets in periodontal patients with type 2 diabetes mellitus (DM2). Patients with residual pockets with probing depth (PD) ≥4mm and bleeding on probing (BOP) were divided into the following groups: SI (n = 17)-subgingival instrumentation in a single session; BM (n=17)-SI followed by local application of active oxygen-releasing gel inside the periodontal pocket for 3min; BM+aPDT (n=17)-SI followed by application of BM for 3min and pocket irrigation with methylene blue, and 660-nm diode laser irradiation at 100mW for 50s. The periodontal clinical parameters, serum levels of glycated hemoglobin, and immunological analysis of crevicular fluid were evaluated. All data were submitted to statistical analysis (α=5%). A significant reduction in BOP was verified at 90 and 180days in the BM+aPDT group. The percentage of sites with PD≥4mm was significantly reduced at 90days in BM+aPDT and BM, whereas after 180days only BM showed a significant reduction. In the BM+aPDT group, there was a significant reduction in tumor necrosis factor α levels at 90days. There were no differences between the treatments. The use of adjuvant active oxygen-releasing gel, with or without aPDT, resulted in the same clinical benefits as SI in the treatment of residual pockets in poorly controlled DM2 patients.

Impact of 810nm diode laser, intraoral and extraoral applications, on postoperative pain, swelling, wound healing, and patient satisfaction following mandibular third molar extraction: a comparative study

Impact of 810nm diode laser, intraoral and extraoral applications, on postoperative pain, swelling, wound healing, and patient satisfaction following mandibular third molar extraction: a comparative study

Noninvasive treatment of cutaneous neurofibromas (cNFs): Results of a randomized prospective, direct comparison of four methods

BackgroundPeople with Neurofibromatosis Type 1 (NF1) suffer disfigurement and pain when hundreds to thousands of cutaneous neurofibromas (cNFs) appear and grow throughout life. Surgical removal of cNFs under anesthesia is the only standard therapy, leaving surgical scars. ObjectiveEffective, minimally-invasive, safe, rapid, tolerable treatment(s) of small cNFs that may prevent tumor progression. MethodsSafety, tolerability, and efficacy of four different treatments were compared in 309, 2-4mm cNFs across 19 adults with Fitzpatrick skin types (FST) I-IV: radiofrequency (RF) needle coagulation, 755nm alexandrite laser with suction, 980nm diode laser, and intratumoral injection of 10mg/mL deoxycholate. Regional pain, clinical responses, tumor height and volume (by 3D photography) were assessed before, 3 and 6 months post-treatment. Biopsies were obtained electively at 3 months. ResultsThere was no scarring or adverse events >grade 2. Each modality significantly (p<0.05) reduced or cleared cNFs, with large variation between tumors and participants. Alexandrite laser and deoxycholate were fast and least painful; 980nm laser was most painful. Growth of cNFs was not stimulated by treatment(s) based on height and volume values at 3 and 6 months compared to baseline. LimitationsIntervention was a single treatment session; dosimetry has not been optimized. ConclusionsSmall cNFs can be rapidly and safely treated without surgery.

Solvent Media on Nonlinear Optical Properties of Triarylmethane Dye via Facile Z-Scan Method.

Solvent environment on third-order nonlinear optical (TNLO) features of triarylmethane dye namely, basic blue 7 in different solvents is reported herein using 650nm diode laser with continuous wave mode. The basic blue 7 dye is dissolved in different solvent media including ethanol, methanol, dimethyl formamide (DMF) and dimethyl sulfoxide (DMSO). The influence of solvent characteristics such as solvent polarizability and dipole moment on solute molecule is discussed. TNLO characteristics such as nonlinear optical index of refraction, nonlinear optical coefficient of absorption, real and imaginary components of the TNLO susceptibility are measured to be the order of 10‒7 cm2/W, 10‒3cm/W, 10‒6 esu and 10‒7 esu, respectively. The dye exhibits large TNLO susceptibility by dissolving in DMSO. The TNLO susceptibility of basic blue 7 dye is measured to be the order of 10‒6 esu. The overall results revealed that the basic blue 7 dye is suitable material for optoelectronics applications.

Molecular spectroscopy as a laboratory experiment: Measurement of important parameters of sodium diatomic molecules

We present an inexpensive sodium molecular spectroscopy experiment for use in an advanced undergraduate laboratory course in physics or chemistry. The molecules were excited predominantly from the ground X1Σg+(v″ = 15) state to the B1Πu(v′ = 6) state using a commercially available 532-nm broadband diode laser. The laser-induced molecular fluorescence was measured using a miniature fiber-coupled spectrometer at a resolution of 0.5 nm. The spectral peak assignments were done by comparing the observed spectrum with the calculated Franck–Condon values. Important molecular constants such as fundamental frequency, anharmonicity, bond strength, and dissociation energy of the ground electronic state were determined by using the Birge–Sponer extrapolation method. The presence of highly visible blue glowing molecules along the green laser beam creates an engaging laboratory experience. Emphasis is placed on students developing their understanding of the molecular structure, practicing molecular spectroscopic techniques, and applying knowledge of light–matter interactions to a physical system.