Electrocautery-Assisted Management of Aberrant Frena Causing Midline Diastema: A Case Report.

Various oral complications such as gingival recession, restricted lip movement and tooth malalignment are the result of an abnormal frenum. Management of these types of frenum is either frenectomy or frenotomy. Methods for performing frenectomies include the conventional scalpel technique, Z-plasty, Miller's technique, V-Y plasty, lasers, and electrocautery. This case report details the successful management of an abnormal frenum attachment using electrocautery to ease and reduce discomfort to the 19-year-old female patient, causing aesthetic concerns. For its precision, minimal bleeding and post-operative discomfort, electrocautery was chosen. This procedure was performed under local anaesthesia. There were favourable post-operative outcomes as the patient experienced minimal pain and rapid recovery from the surgical site. Significant improvement in gingival health was seen in the follow-up examination. This case demonstrates the efficacy of using electrocautery in managing abnormal frenum attachment while highlighting its benefits over traditional surgical methods for ease and reduced discomfort.

Effect of laser irradiation during in-office tooth bleaching on surface properties of resin-based restorative materials.

This study evaluated the changes in surface properties of three resin-based restorative materials after two laser-assisted, in-office tooth bleaching protocols using erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) or diode (980 nm) lasers. A nanohybrid composite (Enamel Plus HRi), a Bis-GMA-free composite (Enamel Plus HRi Bio Function), and a resin-matrix CAD-CAM ceramic (Shofu Block HC) were tested. Forty specimens for each material were prepared and divided into four groups (n = 10/group). The control specimens did not undergo any bleaching treatment, whereas group 2 received bleaching with 40% hydrogen peroxide (H2O2), while groups 3 and 4 underwent the same bleaching procedure with the use of diode (980 nm) or Er,Cr:YSGG lasers, respectively. Surface microhardness and roughness measurements were conducted using a Vickers tester and an optical profilometer. Microhardness was lower in bleached specimens, with the nanohybrid composite exhibiting the largest difference from the no bleaching group. For the Bis-GMA-free composite the microhardness difference between no bleaching and laser-assisted bleaching were smaller than seen for the conventional bleaching technique. Surface roughness was higher in bleached specimens, with nanohybrid composite showing the largest differences from the control specimens. The examined laser-assisted tooth bleaching protocols were found not to impact surface microhardness and roughness of the tested resin-based specimens and they are deemed suitable for clinical use.

Optogenetics in oral and craniofacial research. / å ‰é—ä¼ å­¦åœ¨å£è ”å’Œé¢Œé¢éƒ¨ç ”ç©¶ä¸­çš„åº”ç”¨.

Optogenetics combines optics and genetic engineering to control specific gene expression and biological functions and has the advantages of precise spatiotemporal control, noninvasiveness, and high efficiency. Genetically modified photosensory sensors are engineered into proteins to modulate conformational changes with light stimulation. Therefore, optogenetic techniques can provide new insights into oral biological processes at different levels, ranging from the subcellular and cellular levels to neural circuits and behavioral models. Here, we introduce the origins of optogenetics and highlight the recent progress of optogenetic approaches in oral and craniofacial research, focusing on the ability to apply optogenetics to the study of basic scientific neural mechanisms and to establish different oral behavioral test models in vivo (orofacial movement, licking, eating, and drinking), such as channelrhodopsin (ChR), archaerhodopsin (Arch), and halorhodopsin from Natronomonas pharaonis (NpHR). We also review the synergic and antagonistic effects of optogenetics in preclinical studies of trigeminal neuralgia and maxillofacial cellulitis. In addition, optogenetic tools have been used to control the neurogenic differentiation of dental pulp stem cells in translational studies. Although the scope of optogenetic tools is increasing, there are limited large animal experiments and clinical studies in dental research. Potential future directions include exploring therapeutic strategies for addressing loss of taste in patients with coronavirus disease 2019 (COVID-19), studying oral bacterial biofilms, enhancing craniomaxillofacial and periodontal tissue regeneration, and elucidating the possible pathogenesis of dry sockets, xerostomia, and burning mouth syndrome.

Design, Construction, and Test of Compact, Distributed-Charge, X-Band Accelerator Systems that Enable Image-Guided, VHEE FLASH Radiotherapy.

The design and optimization of laser-Compton x-ray systems based on compact distributed charge accelerator structures can enable micron-scale imaging of disease and the concomitant production of beams of Very High Energy Electrons (VHEEs) capable of producing FLASH-relevant dose rates. The physics of laser-Compton x-ray scattering ensures that the scattered x-rays follow exactly the trajectory of the incident electrons, thus providing a route to image-guided, VHEE FLASH radiotherapy. The keys to a compact architecture capable of producing both laser-Compton x-rays and VHEEs are the use of X-band RF accelerator structures which have been demonstrated to operate with over 100 MeV/m acceleration gradients. The operation of these structures in a distributed charge mode in which each radiofrequency (RF) cycle of the drive RF pulse is filled with a low-charge, high-brightness electron bunch is enabled by the illumination of a high-brightness photogun with a train of UV laser pulses synchronized to the frequency of the underlying accelerator system. The UV pulse trains are created by a patented pulse synthesis approach which utilizes the RF clock of the accelerator to phase and amplitude modulate a narrow band continuous wave (CW) seed laser. In this way it is possible to produce up to 10 µA of average beam current from the accelerator. Such high current from a compact accelerator enables production of sufficient x-rays via laser-Compton scattering for clinical imaging and does so from a machine of "clinical" footprint. At the same time, the production of 1000 or greater individual micro-bunches per RF pulse enables > 10 nC of charge to be produced in a macrobunch of < 100 ns. The design, construction, and test of the 100-MeV class prototype system in Irvine, CA is also presented.

Exploring Carbon Dots: Green Nanomaterials for Unconventional Lasing.

In recent years, the progress toward lighting miniaturization is focused on luminescent nanomaterials. Among them, fluorescent carbon dots (CDs) are receiving increasing attention thanks to their astonishing optical properties complemented by their intrinsic biocompatibility and low toxicity. The CDs can be easily dispersed in water, organic solvents or incorporated in polymeric matrices, preserving their emission properties. However, the relationship between their structural and optical properties is still not fully elucidated, motivating a consistent research effort for the comprehension of their features. Nevertheless, CDs demonstrate to be efficient gain materials for lasing, thanks to their high quantum yield (QY), emission tunability in the visible and near infrared (NIR) range, short lifetimes, and high absorption cross section, even if the synthetic reproducibility, the low reaction yield and the spectral width of the emission may limit their effective exploitation. This review summarizes the latest advancements in the investigation of the characteristic properties of CDs that make laser action possible, illustrating optical geometries for lasing and random lasing, both in solution and solid state, and the few currently demonstrated breakthroughs. While the journey toward their effective application is still long, the potential of CD-based laser sources is promising in various technological fields and futuristic perspectives will be discussed.

Outcomes of ureteroscopy and laser fragmentation using a 60 W MOSES laser: a 3-year prospective study from a University Teaching Hospital.

Introduction: Modulated optics enhancement system (MOSES) holmium lasers use "pulse modulation" to increase the efficacy of laser lithotripsy. As the clinical evidence on the efficacy of 60 W holmium laser with MOSES technology is scarce, we analyzed the outcomes of patients treated with this laser at our institution. Methods: A total of 96 consecutive patients with urinary stones (72 renal stones and 24 ureteral stones) were treated with the 60 W MOSES laser from 2019 until 2022 and were included in our analysis. Patient data and outcomes were prospectively collected, and analysis was performed regarding patient demographics, stone parameters, as well as stone-free rate, operating time, length of stay, and perioperative and postoperative complications. Results: With a median age of 55 (IQR: 35-69.25) years, the male:female ratio was 53:43. The median stone size was 12 mm (IQR: 7-19), with a mean number of urinary stones of 1.82 (SD ± 1.4). While 36 (35%) patients were pre-stented, a ureteral access sheath was inserted in 36 (37.5%) patients. The median operative time was 44 min (IQR: 22.5-59.5), and 63 (65.5%) patients received postoperative stenting. Perioperative complications (all Clavien ⩽ II complications) were observed in 5 (5.2%) patients (four urinary tract infections and one acute urinary retention), and after the first procedure, 90 (93.8%) patients were stone-free. The median length of hospital stay was 1 day (IQR: 1-1). Conclusion: This study demonstrated that the 60 W MOSES laser was safe and efficient for the treatment of urinary stones with high stone-free rates and a small risk of minor complications. More studies with larger cohorts are necessary in the future to confirm our results.

Indications and Outcomes of Laser Retinopexy in Eyes With High-Risk Lattice Degeneration.

Purpose: To examine the characteristics of eyes with high-risk lattice degeneration treated with laser retinopexy and determine the indications, safety, and outcomes of the treatment. Methods: This interventional single-surgeon consecutive retrospective study was conducted at Wills Eye Hospital between 2014 and 2021. The series included eyes with lattice degeneration with high-risk lesions. Documented characteristics and outcomes of these eyes and fellow eyes were documented. Results: The study comprised 167 eyes of 143 patients (53.3% women; mean age [±SD], 50 ± 17 years). Complications after laser treatment included new posterior vitreous detachment (PVD) (n = 21), epiretinal membrane (ERM) (n = 13), retinal detachment (RD) (n = 5), and additional laser required (n = 22). Eyes that developed ERMs were more likely to develop PVDs (odds ratio, 5.39; 95% CI, 1.57-18.47). Patents who developed ERMs were older (mean, 60 ± 7 years vs 49 ± 17 years; P = .016), as were those developing PVDs (mean, 59 ± 8 years vs 48 ± 17; P = .005). No eye with a new ERM required surgery (n = 13). Four eyes with a new RD required laser retinopexy alone; 1 eye was treated surgically. No eye had an RD at the most recent evaluation. Conclusions: Despite high-risk lesions in areas of lattice degeneration, few eyes developed RDs after prophylactic laser retinopexy. Older patients may have a higher risk for ERM or PVD after laser treatment. Eyes with post-laser PVD were more likely to develop an ERM.

Effect of Er:YAG Laser Application and Sandblasting on Shear Bond Strength of Veneering Ceramic to Zirconia Core.

Objectives: Porcelain chipping and delamination are among the shortcomings of all-ceramic restorations. This study aimed to assess the effect of laser irradiation and sandblasting on shear bond strength (SBS) of zirconia to veneering porcelain. Materials and Methods: In this in vitro, experimental study, 60 zirconia blocks were randomly divided into three groups (n=20) for surface treatment with Er:YAG laser, sandblasting, and no surface treatment (control). Each group was randomly divided into two subgroups (n=10) for porcelain application by the layering or the pressing technique. The surface roughness, SBS, and failure mode were determined and analyzed using two-way ANOVA, Tukey's HSD test, Chi-square test, and Pearson's correlation test (alpha=0.05). Results: The mean SBS was 8.16±3.66 MPa, 9.32±2.7 MPa, and 11.85±3.06 MPa in the control, laser, and sandblasting groups, respectively. The SBS was significantly different among the three groups (P=0.002). The failure mode of the three groups was not significantly different (P>0.05). The sandblasted group showed significantly higher surface roughness than the control and laser groups (P<0.001). Conclusion: Sandblasting yielded higher SBS particularly when the porcelain was applied by the layering technique. Although laser irradiation increased the SBS, the difference with the control group was not statistically significant.

The role of excimer light in dermatology: a review.

Excimer light is a subtype of NB-UVB that emits a 308 nm wavelength, and can provide targeted phototherapy treatment. The absorption of 308 nm light by skin cells leads to therapeutic response in various common and ultraviolet-responsive skin diseases, such as psoriasis and vitiligo, and photo-resistant skin diseases such as prurigo nodularis, localized scleroderma, genital lichen sclerosis, and granuloma annulare, cutaneous T-cell lymphomas, among others. Excimer light has few adverse reactions and overall is well tolerated by patients, furthermore, it can be performed in places that are difficult to access. This article aims to explain the therapeutic bases and applications of excimer light in current dermatology.

Micronano Lasers Based on Aggregation-Induced Emission Molecules: Diverse Resonant Cavities Investigation.

Aggregation-induced emission (AIE) molecules have great potential to enhance the performance of micronano lasers due to their excellent aggregated luminescence properties, so it is valuable to expand their applications in micronano lasers. In this work, a typical AIE active fluorescent dye motif 9,10-bis(2,2-diphenylvinyl) anthracene (BDPVA) was selected as the gain medium. First, drop-casting was used to fabricate BDPVA single-crystal nanowires, which can be used as Fabry-Perot (FP)-type resonators with a lasing threshold of 49.4 µJ/cm2. Furthermore, we innovatively doped BDPVA molecules as gain mediums into external polymer Whispering-Gallery-Mode (WGM)-type resonators via the emulsion self-assembly method. Fabricated BDPVA-doped polystyrene (PS) microspheres exhibit a much lower lasing threshold of 9.04 µJ/cm2. These results prove that the BDPVA molecules, in addition to realizing the reported AIE single-crystal lasers, can also be used as a guest-doped gain medium in the resonant cavity for obtaining better fluorescence gain. In addition, multimode tunability of two types of lasers has been successfully achieved by tuning the structure of the resonant cavity. This work further expands the application potential of AIE materials and will provide a useful reference for the rational design and fabrication of photonic micronano laser components using AIE materials.

Efficacy of High-intensity laser therapy in patients with temporomandibular joint disorders: A systematic review and meta-analysis.

This study aimed to assess the effects of High-intensity laser therapy (HILT) on individuals suffering from temporomandibular joint disorders (TMDs). A search was conducted across six electronic databases for randomized controlled trials (RCTs) focusing on HILT for TMDs: PubMed, Scopus, Web of Science, ScienceDirect, EBSCOhost, Cochrane Library, the PEDro database and Google Scholar (last updated on July 18, 2024). Eligible studies were chosen by independent reviewers, and their quality was assessed with the Cochrane risk of bias tool (RoB). The main outcome was pain intensity (VAS), with secondary outcomes including mouth opening (mm), disability (JFLS-20), and quality of life (OHIP-14). A meta-analysis was conducted to assess the pooled effect by calculating mean differences (MD) for these variables (95% confidence level). The heterogeneity of the meta-analyses was explored using the I2 statistic. Three studies met the selection criteria and were included in the meta-analysis. The main RoB was the blinding of participant and treaters. Statistically significant differences (p < 0.05) in favor of HILT were observed for VAS and maximum mouth opening. The pooled effect showed an MD of -14.8 mm (95% CI:-27.1,-2.5) for pain intensity and 3.7 mm (95% CI:0.9,6.5) for mouth opening, changes that were assessed as clinically important. According to GRADE, the evidence was rated as important, and the certainty was moderate due to the heterogeneity between studies. A sensitivity analysis was not performed to address heterogeneity, primarily due to the limited availability of RCTs. HILT has been found effective in short-term pain relief and improvement of jaw opening in TMDs, potentially enhancing quality of life by facilitating activities such as chewing, jaw mobility, and communication. However, further research is needed to confirm its long-term effectiveness. Combining HILT with interventions such as occlusal splints or therapeutic exercises could potentially enhance its effects, leveraging the existing evidence supporting these treatments. It is important to note that the high RoB associated with the lack of blinding of participants and treaters may influence data collection, compromising the internal validity of findings in some studies.

Enhanced quantification of chlorophyll a and its degradation products in olive oil using time-resolved laser-induced fluorescence fingerprint analysis.

Potential errors in the fluorescence analysis of chlorophylls and their degradation products, primarily due to spectral overlap and inner filter, are widely acknowledged. This study aimed to devise a sensitivity-enhanced technique for the concurrent quantification of chlorophyll a and its degradation products while minimizing effects from type-B chlorophylls. Initially, a time-resolved laser-induced fluorescence spectroscopic system was designed and tested on stardard chlorophyll samples. The origins, implications, and mitigation strategies of spectral overlap and the inner filter effect on the measured fluorescence intensity were thoroughly examined. Then, this methodology was proved to be efficacious within complex liquid matrices derived from olive oil. The experimental outcomes not only shed additional light on the mechanisms of chlorophyll fluorescence overlap and the inner filter effect, but also establish a general framework for developing spectrally and timely resolved fluorescence fingerprint analysis for the simultaneous quantification of chlorophylls and their degradation products at high concentrations.

Physical Treatments and Therapies for Androgenetic Alopecia.

Androgenetic alopecia, the most common cause of hair loss affecting both men and women, is typically treated using pharmaceutical options, such as minoxidil and finasteride. While these medications work for many individuals, they are not suitable options for all. To date, the only non-pharmaceutical option that the United States Food and Drug Administration has cleared as a treatment for androgenetic alopecia is low-level laser therapy (LLLT). Numerous clinical trials utilizing LLLT devices of various types are available. However, a myriad of other physical treatments for this form of hair loss have been reported in the literature. This review evaluated the effectiveness of microneedling, pulsed electromagnetic field (PEMF) therapy, low-level laser therapy (LLLT), fractional laser therapy, and nonablative laser therapy for the treatment of androgenetic alopecia (AGA). It also explores the potential of multimodal treatments combining these physical therapies. The majority of evidence in the literature supports LLLT as a physical therapy for androgenetic alopecia. However, other physical treatments, such as nonablative laser treatments, and multimodal approaches, such as PEMF-LLLT, seem to have the potential to be equally or more promising and merit further exploration.

Safety and efficacy of lasers compared to cold knife in direct visual internal urethrotomy: a systematic review and Meta-analysis.

Cold knife urethrotome was introduced in 1971 and it had an 80% success rate. New advancements in this field have shed light on the use of various lasers such as carbon dioxide, Nd: YAG, KTP, Argon, Ho: YAG, and excimer lasers. It has been observed that cold knife urethrotomy has a higher recurrence rate than laser urethrotomy, but the superiority of either treatment modality has not been established yet. Data were thoroughly searched through PubMed, Scopus, and clinicaltrials.gov. We also used clinicaltrials.gov for ongoing and published research. The data was analyzed via R studio version 2023.12.1 (oceanstorm). For dichotomous variables, Odds Ratio (OR) were used to pool data and standardized mean difference was used for continuous variables with 95% confidence intervals (CIs). A total of 14 studies including 1114 participants were included in this meta-analysis. The results of the combined analysis revealed significant relation with a mean difference of 0.99 (95% CI: 0.37; 1.62), and favored laser group. The overall results have shown the laser to have a significant favorable profile demonstrating a recurrence, Odds Ratio of 0.42 (95% CI:0.27;0.65). Patients with laser therapy had a lower risk of complication rate (OR 0.49, 95% Cl: 0.35; 0.67). All the findings obtained by the analysis in this study favour lasers significantly over the cold knife technique especially when mean Qmax, with recurrence and complications taken into account.

Unusual case of Reinke's oedema.

This case report describes a man in his mid 40s, with a history of chronic smoking, who presented with dysphonia. He underwent microlaryngoscopy and biopsy for a suspicious lesion on the anterior right vocal cord. Mask ventilation proved difficult on induction of general anaesthesia due to a solid lesion acting as a ball valve into the glottis. This mass was LASER debulked and sent for histopathology. This demonstrated a haematoma, likely traumatic in origin, with some polypoidal features, consistent with advanced Reinke's oedema. Reinke's oedema is a benign condition where chronic inflammation causes fluid accumulation within the vocal cords. Long-standing inflammation leads to disarrangement of the vocal cord lamina propria, causing fluid accumulation and thereby resulting oedema of the vocal cords. This process can subsequently lead to polyp formation and can cause gravelly voice. This case report describes the potential airway sequelae of this benign condition.

Examining the Efficacy of a 405 nm Wavelength Diode Laser as a Diagnostic Tool in Routine Dental Practice.

In recent years, significant advancements in dental and periodontal diagnostics have paved the way for improved care. Among the available approaches, laser fluorescence (LF) is a promising method. This case report explores the utilization of a 405 nm diode laser as a diagnostic tool in the non-surgical treatment of biofilm-induced gingivitis, as well as its application in routine daily practice for diagnosing restorations and dental caries. A 24-year-old male patient and a 21-year-old female patient were included. A 405 nm diode laser (Smart M, Lasotronix, Poland) was used as a diagnostic tool with a tip diameter of 8 mm. In case one, the utilization of the 405 nm diode laser enhanced the patient's ability to perceive the presence and extent of plaque and calculus, aiding in motivation and education regarding supra-gingival dental biofilm control and it assisted the operator in precisely localizing plaque and calculus, thereby enabling more effective mechanical debridement and ultimately improving treatment outcomes. In the second case, the utilization of the laser facilitated the detection of defective composite fillings aiding in both accurate diagnosis for the operator and effective communication with the patient regarding the need for re-treatment. This study illustrates the potential of the relatively new 405 nm diode laser as a promising diagnostic tool in the daily management of periodontal patients and the detection of defective dental fillings in daily practice.

Non-contact elasticity contrast imaging using photon counting.

Significance: Tissues' biomechanical properties, such as elasticity, are related to tissue health. Optical coherence elastography produces images of tissues based on their elasticity, but its performance is constrained by the laser power used, working distance, and excitation methods. Aim: We develop a new method to reconstruct the elasticity contrast image over a long working distance, with only low-intensity illumination, and by non-contact acoustic wave excitation. Approach: We combine single-photon vibrometry and quantum parametric mode sorting (QPMS) to measure the oscillating backscattered signals at a single-photon level and derive the phantoms' relative elasticity. Results: We test our system on tissue-mimicking phantoms consisting of contrast sections with different concentrations and thus stiffness. Our results show that as the driving acoustic frequency is swept, the phantoms' vibrational responses are mapped onto the photon-counting histograms from which their mechanical properties-including elasticity-can be derived. Through lateral and longitudinal laser scanning at a fixed frequency, a contrast image based on samples' elasticity can be reliably reconstructed upon photon level signals. Conclusions: We demonstrated the reliability of QPMS-based elasticity contrast imaging of agar phantoms in a long working distance, low-intensity environment. This technique has the potential for in-depth images of real biological tissue and provides a new approach to elastography research and applications.

Clinical outcomes of holmium laser enucleation of the prostate: A large prospective registry-based patient cohort study under regular follow-up protocol.

PURPOSE: To evaluate the efficacy and safety of holmium laser enucleation of the prostate (HoLEP) in a large prospective cohort of patients with benign prostatic hyperplasia (BPH) through systematic follow-up at a single institution. MATERIALS AND METHODS: Clinical outcomes were analyzed between August 2008 and June 2022. Patients were followed-up at 2 weeks, 3 months and 6 months postoperatively. RESULTS: A total of 3,000 patients (mean age, 69.6±7.7 years) underwent HoLEP. Baseline total International Prostate Symptom Score (IPSS) was 19.3±7.7 and maximum flow rate (Qmax) was 9.4±4.8 mL/s. Mean total prostate volume was 67.7±3.4 mL. Total operation time was 60.7±31.5 minutes, and catheterization time was 1.0 days (range, 1.0-1.0 days). At 6 months postoperatively, the total IPSS decreased to 6.6±5.8 and Qmax increased to 22.2±11.3 mL/s. Complications at 6 months postoperatively included stress urinary incontinence (SUI) in 36 patients (1.9%), urgency urinary incontinence (UUI) in 25 (1.3%), bladder neck contracture (BNC) requiring transurethral incision (TUI) in 16 (0.5%), and urethral stricture in 29 (1.0%). Eleven patients (0.4%) with prostatic fossa stones required stone removal. Sixty-one patients (2.0%) required secondary surgery (transurethral coagulation, 16 [0.5%]; TUI for BNC, 16 [0.5%]; stone removal for prostatic fossa stones, 11 [0.4%]; and endoscopic internal urethrotomy for urethral stricture, 18 [0.6%]). CONCLUSIONS: Mid-term follow-up results after HoLEP in BPH patients showed excellent efficacy and low complication rates. Unlike previous reports, the incidence of SUI and UUI after HoLEP was low, but the occurrence of de novo stone formation in prostatic fossa was notable.

[4]Rhombene: Solution-Phase Synthesis and Application in Distributed Feedback Lasers With Emission Beyond 830†nm.

Graphene-like molecules with multiple zigzag edges are emerging as promising gain materials for organic lasers. Their emission wavelengths can vary widely, ranging from visible to near-infrared (NIR), as the molecular size increases. Specifically, rhombus-shaped molecular graphenes with two pairs of parallel zigzag edges, known as [n]rhombenes, are excellent candidates for NIR lasers due to their small energy gaps. However, synthesizing large-size rhombenes with emission beyond 800 nm in solution remains a significant challenge. In this study, we present a straightforward synthesis of an aryl-substituted [4]rhombene derivative, [4]RB-Ar, using a method that combines intramolecular radical-radical coupling with Bi(OTf)3-mediated cyclization of vinyl ethers. The structure of [4]RB-Ar was confirmed through X-ray crystallographic analysis. Bond length analysis and theoretical calculations indicate that aromatic sextets are predominantly localized along the molecule's long axis. Significantly, [4]RB-Ar demonstrates narrow amplified spontaneous emission at around 834 nm when dispersed in polystyrene thin films. Moreover, solution-processed distributed feedback lasers employing [4]RB-Ar as the active gain material display tunable narrow emissions in the range of 830 to 844 nm.

Laser-Induced Koebner-Related Skin Reactions: A Clinical Overview.

The Koebner phenomenon (KP), also known as the isomorphic response, describes the process by which new lesions that are clinically and histologically identical to a patient's existing skin disease develop following trauma. Many skin diseases exhibit this characteristic, with variations that include possible, questionable, and pseudo-Koebner reactions, with the latter category occurring due to infectious agents seeding at a trauma site. Laser application, a type of controlled skin injury used for improving cutaneous lesions and skin rejuvenation, is also considered a form of trauma. This raises the question of whether controlled thermal injury can be regarded as a type of mechanical trauma capable of producing Koebner-related reactions. We conducted a literature review of cases or studies to identify laser-induced dermatoses that correspond to Koebner-related or pathergy reaction categories. As a whole, we identified nine case reports on true KPs, two cases on possible KPs, seventeen cases on laser-induced questionable KPs comprising cases of vasculitis, eczema or Meyerson reactions, and eruptive squamous atypia cases (ESA) as well as two pseudo-Koebner cases involving wart occurrences at laser application sites. Laser-induced Koebner reactions highlight several aspects of the KP. Firstly, the type of mechanical damage influences disease promotion, as different lasers are associated with different KPs. For example, hair removal lasers are linked with true and questionable KPs such as vasculitis while resurfacing lasers were found to be more connected with ESA occurrence. Secondly, the laser target is significant, with vascular laser application for port-wine stains tending to result in eczematous reactions, while hair follicle destruction can frequently lead to true KPs. Thirdly, the number of sessions matters; true KPs and eruptive squamous atypia questionable KPs typically appear after one to two sessions, whereas eczematous reactions require more sessions (at least four). Additionally, skin phototype is crucial, with darker phototypes showing a higher KP frequency as laser treatment for hypertrichosis relies on melanin absorption in the hair bulge or bulb for follicle destruction, as chromophore competes with the abundant melanin in the epidermis. Further research with larger-scale studies into trauma-specific Koebner reactions is vital for refining treatment protocols, minimizing post-laser adverse effects, and improving dermatological care outcomes.