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Electron Microscopy of Argyria Treated With Picosecond Alexandrite Laser
摘要： Argyria (from the Greek word for silver, argyros) is the bluish gray discoloration of tissue caused by exposure to silver or its salts, often because of alternative medicine treatment or occasionally through occupational exposure. Since the 1990s, colloidal silver has been available in pharmacy-supplied dietary supplements and homeopathic remedies for the treatment of various diseases, including cancer, immunodeficiency, chronic fatigue, tuberculosis, and other infections, without any substantiating evidence. Long-term consumption of silver products can lead to chronic argyria, with silver deposition in organs, including the skin, liver, spleen, kidneys, and central and peripheral nervous system. Generalized argyria can occur when silver compounds are ingested, applied topically, or inhaled. Argyria can also be localized to certain sites of the skin or eyes if creams or eye drops are used or can be found on the ear lobes when silver earrings are worn. Silver deposits may localize in the eccrine glands of the skin, as well as in the papillary dermis and pilosebaceous follicles. The silver is in the form of silver sulfide and appears to be more abundant in the sun-exposed skin. Argyria has a well-defined toxicity, and discoloration is permanent. Recently, Q-switched nanosecond laser and picosecond alexandrite laser (PicoSure, Cynosure) have been used to treat argyria. Both the Q-switched nanosecond laser and the picosecond alexandrite laser use the principle of selective photothermolysis and have been used in a number of applications, including tattoo removal and pigmentation removal. Pulses of light energy is delivered to the skin and causes fragmentation of ink particles, allowing for phagocytosis and removal of the pigment by macrophages. It is speculated that laser treatment of argyria causes fragmentation of silver deposits in the skin, similar to the mechanisms of tattoo removal. We present a case report of the successful treatment of argyria with picosecond alexandrite laser, as demonstrated by clinical photographs, histopathology, and electron microscopy. This case provides evidence that picosecond laser causes the fragmentation of silver particles in argyria without phagocytosis in the immediate post-treatment phase.
关键词： picosecond alexandrite laser,silver particles,argyria,laser treatment,electron microscopy
更新于2025-09-12 10:27:22
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Shape Controllable Synthesis of Silver Particles by Selecting the Crystallization Routes
摘要： Classic crystallization describes a burst nucleation followed by a layer-by-layer atom deposition. The non-classic crystallization refers to particle mediated crystallization process. Different crystallization routes lead to the formation of diverse structured materials. Here we report a rational synthesis of silver particles by selecting the crystallization routes. Silver particles were synthesized by a solution reduction approach. The crystallization routes were regulated by adding amino acids to stabilize silver ions which leads to the decrease of the reduction rate. Without amino acids, silver dendrites were largely formed. With the addition of amino acids, flower-like (low concentration of amino acids) and spherical silver (high concentration of amino acid) particles were synthesized. Three kinds of amino acids were tested and the similar results were obtained. The time-dependent characterization on the evolution of silver particles showed that silver dendrites were formed by the classic atom deposition while the other two morphologies were formed by the combination of classic and non-classic crystallization. The silver particles synthesized were evaluated for ethylene epoxidation and the dendritic particles demonstrated a high selectivity.
关键词： catalytic selectivity,silver particles,reaction kinetics,shape control,crystallization
更新于2025-09-09 09:28:46
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Ag release from sputtered Ag/a:C nanocomposite films after immersion in pure water and NaCl solution
摘要： Diamond-like carbon (DLC) coatings doped with Ag nanoparticles are promising materials for several application, as, for example, a biomaterial. In addition to their numerous properties, when doped with silver, DLCs can acquire antibacterial properties. In this study, Ag/a:C films were deposited by unbalanced magnetron sputtering. The dimension and distribution of silver nanoparticles in the carbon matrix were characterized before and after immersion in different liquid environments, ultra-pure water and NaCl (0.9%). Inductively coupled plasma-optical emission spectroscopy was used to quantify the Ag ions released from the film. Based on the aspect of Ag nanoparticles on the films surface, suggested by atomic force microscopy analysis, scanning electron microscopy was performed to access the dimension and the distribution of the nanoparticles at the surface and, then, to calculate the mass of Ag in the film, before and after exposure to both liquids. Agglomeration and coalescence of the nanoparticles in the film surface were studied and information about the segregation from the bulk to the surface was achieved, also confirmed by X-ray photoelectron spectroscopy analysis.
关键词： Coalescence,Sputtering,Ions released,Silver,Particles,Segregation,Amorphous carbon
更新于2025-09-04 15:30:14