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Actas Dermo-sifiliograficas 2022Burn scars cause high morbidity in the form of contractures, body disfigurement, and itching, and they also have a high emotional impact that adversely affects patient... (Review)
Review
Burn scars cause high morbidity in the form of contractures, body disfigurement, and itching, and they also have a high emotional impact that adversely affects patient quality of life. Laser therapy has proven effective in this setting. It is superior to topical treatments and can be used in conjunction with surgery, helping to reduce morbidity. The use of lasers in hospital dermatology departments, however, is still limited. Carbon dioxide laser resurfacing is the most widely used modality for reducing scar thickness, improving textural abnormalities, and treating contractures. Treatments improve mobility for patients with constrictions. Pulsed dye laser treatments are particularly useful for reducing erythema in recent burn scars and preventing subsequent hypertrophy. Pigment laser treatments with short pulse durations (nanoseconds or picoseconds) can improve hyperpigmentation. In this article, we review the evidence for the use of laser therapy for burn scars and propose a treatment algorithm.
Topics: Humans; Cicatrix; Cicatrix, Hypertrophic; Lasers, Gas; Burns; Quality of Life; Laser Therapy; Contracture; Treatment Outcome
PubMed: 35963335
DOI: 10.1016/j.ad.2022.06.018 -
Lasers in Medical Science Jan 2023Picosecond lasers have a very short pulse duration and a high peak power density. When fractional optical delivery systems are attached to picosecond lasers, they... (Review)
Review
Picosecond lasers have a very short pulse duration and a high peak power density. When fractional optical delivery systems are attached to picosecond lasers, they generate an array of concentrated microspots with a high fluence surrounded by areas with a low fluence. This article discusses the histologic characteristics and clinical applications of fractional picosecond laser treatment. Fractional picosecond laser produces laser-induced optical breakdown (LIOB) and laser-induced cavitation (LIC) in the epidermis and dermis respectively, and can encourage skin regeneration and dermal remodeling. It has been shown that fractional picosecond laser has a positive effect on facial photoaging, enlarged facial pores, dyspigmentation, wrinkles, and atrophic scars. Further research is still needed to confirm the benefits of fractional picosecond lasers.
Topics: Humans; Lasers, Solid-State; Skin; Epidermis; Cicatrix; Pigmentation Disorders; Treatment Outcome
PubMed: 36658259
DOI: 10.1007/s10103-022-03704-y -
Dermatologie (Heidelberg, Germany) Jun 2023The picosecond laser is one of the latest laser systems in dermatology and was originally developed to optimize tattoo removal. Advances in this technology has expanded... (Review)
Review
BACKGROUND
The picosecond laser is one of the latest laser systems in dermatology and was originally developed to optimize tattoo removal. Advances in this technology has expanded the use of the picosecond laser to numerous other indications.
OBJECTIVES
This article provides an overview of the technical background as well as the indications of the picosecond laser in dermatological laser medicine and elucidates the possibilities and limits of this laser system.
MATERIALS AND METHODS
The article is based on a review of the current literature as well as experience from clinical practice in a university laser department.
RESULTS
The picosecond laser enables a particularly gentle and effective treatment due to ultra-short pulses and the principle of laser-induced optical breakdown. Compared to Q‑switched lasers, the picosecond laser has fewer side effects and is associated with lower pain intensity and shorter downtime. In addition to the removal of tattoos and pigmentary disorders, it is also used in the treatment of scars and rejuvenation.
CONCLUSIONS
The picosecond laser has a wide range of indications in dermatological laser medicine. The current data indicate that the laser is an effective method with few side effects. Further prospective studies have to be conducted to assess the efficacy, tolerability and patient satisfaction in an evidence-based manner.
Topics: Humans; Prospective Studies; Dermatology; Lasers; Tattooing; Laser Therapy; Drug-Related Side Effects and Adverse Reactions
PubMed: 37099130
DOI: 10.1007/s00105-023-05144-3 -
Frontiers in Physics 2023Brillouin microscopy based on spontaneous Brillouin scattering has emerged as a unique elastography technique because of its merit of non-contact, label-free, and...
Brillouin microscopy based on spontaneous Brillouin scattering has emerged as a unique elastography technique because of its merit of non-contact, label-free, and high-resolution mechanical imaging of biological cell and tissue. Recently, several new optical modalities based on stimulated Brillouin scattering have been developed for biomechanical research. As the scattering efficiency of the stimulated process is much higher than its counterpart in the spontaneous process, stimulated Brillouin-based methods have the potential to significantly improve the speed and spectral resolution of existing Brillouin microscopy. Here, we review the ongoing technological advancements of three methods, including continuous wave stimulated Brillouin microscopy, impulsive stimulated Brillouin microscopy, and laser-induced picosecond ultrasonics. We describe the physical principle, the representative instrumentation, and biological application of each method. We further discuss the current limitations as well as the challenges for translating these methods into a visible biomedical instrument for biophysics and mechanobiology.
PubMed: 37377499
DOI: 10.3389/fphy.2023.1175653 -
Sensors (Basel, Switzerland) Apr 2021Fast gating in Raman spectroscopy is used to reject the fluorescence contribution from the sample and/or the substrate. Several techniques have been set up in the last... (Review)
Review
Fast gating in Raman spectroscopy is used to reject the fluorescence contribution from the sample and/or the substrate. Several techniques have been set up in the last few decades aiming either to enhance the Raman signal (CARS, SERS or Resonant Raman scattering) or to cancel out the fluorescence contribution (SERDS), and a number of reviews have already been published on these sub-topics. However, for many reasons it is sometimes necessary to reject fluorescence in traditional Raman spectroscopy, and in the last few decades a variety of papers dealt with this issue, which is still challenging due to the time scales at stake (down to picoseconds). Fast gating (<1 ns) in the time domain allows one to cut off part of the fluorescence signal and retrieve the best Raman signal, depending on the fluorescence lifetime of the sample and laser pulse duration. In particular, three different techniques have been developed to accomplish this task: optical Kerr cells, intensified Charge Coupling Devices and systems based on Single Photon Avalanche Photodiodes. The utility of time domain fast gating will be discussed, and In this work, the utility of time domain fast gating is discussed, as well as the performances of the mentioned techniques as reported in literature.
PubMed: 33916972
DOI: 10.3390/s21082579 -
PLoS Computational Biology Mar 2016Nuclear magnetic resonance (NMR) spectroscopy provides a unique toolbox of experimental probes for studying dynamic processes on a wide range of timescales, ranging from... (Review)
Review
Nuclear magnetic resonance (NMR) spectroscopy provides a unique toolbox of experimental probes for studying dynamic processes on a wide range of timescales, ranging from picoseconds to milliseconds and beyond. Along with NMR hardware developments, recent methodological advancements have enabled the characterization of allosteric proteins at unprecedented detail, revealing intriguing aspects of allosteric mechanisms and increasing the proportion of the conformational ensemble that can be observed by experiment. Here, we present an overview of NMR spectroscopic methods for characterizing equilibrium fluctuations in free and bound states of allosteric proteins that have been most influential in the field. By combining NMR experimental approaches with molecular simulations, atomistic-level descriptions of the mechanisms by which allosteric phenomena take place are now within reach.
Topics: Allosteric Regulation; Allosteric Site; Amino Acid Sequence; Enzyme Activation; Enzymes; Magnetic Resonance Spectroscopy; Models, Chemical; Molecular Dynamics Simulation; Molecular Sequence Data; Protein Binding; Sequence Analysis, Protein
PubMed: 26964042
DOI: 10.1371/journal.pcbi.1004620 -
World Journal of Otorhinolaryngology -... Oct 2021Cold-steel has served as the gold standard modality of phonosurgery for most of its history. Surgical laser technology has revolutionized this field with its wide use of... (Review)
Review
Cold-steel has served as the gold standard modality of phonosurgery for most of its history. Surgical laser technology has revolutionized this field with its wide use of applications. Additional modalities have also been introduced such as coagulative lasers, photodynamic therapy, and cryotherapy. This review will compare the surgical modalities of cold steel, surgical lasers, phototherapy and cryotherapy. The mechanism of action, tissue effects and typical uses will be addressed for each modality.
PubMed: 34632350
DOI: 10.1016/j.wjorl.2020.09.001 -
Nature Communications Mar 2023Multidimensional imaging of transient events has proven pivotal in unveiling many fundamental mechanisms in physics, chemistry, and biology. In particular, real-time...
Multidimensional imaging of transient events has proven pivotal in unveiling many fundamental mechanisms in physics, chemistry, and biology. In particular, real-time imaging modalities with ultrahigh temporal resolutions are required for capturing ultrashort events on picosecond timescales. Despite recent approaches witnessing a dramatic boost in high-speed photography, current single-shot ultrafast imaging schemes operate only at conventional optical wavelengths, being suitable solely within an optically-transparent framework. Here, leveraging on the unique penetration capability of terahertz radiation, we demonstrate a single-shot ultrafast terahertz photography system that can capture multiple frames of a complex ultrafast scene in non-transparent media with sub-picosecond temporal resolution. By multiplexing an optical probe beam in both the time and spatial-frequency domains, we encode the terahertz-captured three-dimensional dynamics into distinct spatial-frequency regions of a superimposed optical image, which is then computationally decoded and reconstructed. Our approach opens up the investigation of non-repeatable or destructive events that occur in optically-opaque scenarios.
PubMed: 36973242
DOI: 10.1038/s41467-023-37285-3 -
Photoacoustics Jun 2023This review discusses picosecond ultrasonics experiments using ultrashort hard x-ray probe pulses to extract the transient strain response of laser-excited nanoscopic... (Review)
Review
This review discusses picosecond ultrasonics experiments using ultrashort hard x-ray probe pulses to extract the transient strain response of laser-excited nanoscopic structures from Bragg-peak shifts. This method provides direct, layer-specific, and quantitative information on the picosecond strain response for structures down to few-nm thickness. We model the transient strain using the elastic wave equation and express the driving stress using Grüneisen parameters stating that the laser-induced stress is proportional to energy density changes in the microscopic subsystems of the solid, i.e., electrons, phonons and spins. The laser-driven strain response can thus serve as an ultrafast proxy for local energy-density and temperature changes, but we emphasize the importance of the nanoscale morphology for an accurate interpretation due to the Poisson effect. The presented experimental use cases encompass ultrathin and opaque metal-heterostructures, continuous and granular nanolayers as well as negative thermal expansion materials, that each pose a challenge to established all-optical techniques.
PubMed: 37275326
DOI: 10.1016/j.pacs.2023.100503