Laser-Induced Smoke in Dermatologic Practice: A Survey to Explore Hazard Perceptions, Safety Measures and Unmet Needs.

Introduction: Inhalation of laser-induced smoke is a potential health hazard to exposed physicians and laser operators. To date, little is known about the perception of health hazards related to laser-induced smoke exposure among physicians and the actual use of safety measures to mitigate these risks. Methods: In May 2020, 514 members of the European Society for Lasers and Energy-Based Devices (ESLD) were invited by email to participate in an online survey. The survey comprised 16 questions including multiple-choice and open-ended questions. Results: Responses were received from 109 participants. The majority (90%) were aware of potential hazards and highlighted a desire for better protective measures (60%). A smoke evacuation system was frequently used with ablative lasers (66%) and fractional ablative lasers (61%), but less the case with non-ablative lasers (30%) and hair removal lasers (28%). The COVID-19 outbreak had no clear effect on the use of smoke evacuation systems. Prior to the COVID-19 outbreak, mainly surgical masks were used (40-57%), while high filtration masks (FFP1, FFP2 or FFP3) were used by only a small percentage (15-30%). Post COVID-19 outbreak, the use of high filtration masks increased significantly (54-66%), predominately due to an increase in the use of FFP2 masks. Reasons mentioned for inadequate protective measures were sparse knowledge, limited availability, discomfort, excessive noise, high room temperatures, and financial costs. Conclusion: While there is considerable awareness of the hazards of laser-induced smoke among physicians and laser operators, a substantial number of them do not use appropriate protective measures. The implementation of regulations on safety measures is hampered by sparse knowledge, limited availability, discomfort, excessive noise, financial issues, and high room temperatures.

Single-walled metal-organic nanotube built from a simple synthon.

A conformationally flexible triazole-carboxylic acid ligand derived from an L-amino acid, namely, 4 H-1,2,4-triazol-4-yl-acetic acid (αHGlytrz), has been exploited to synthesize a structurally diverse and functionally intriguing metal-organic framework with CuSiF6. The crystal structure reveals a novel single-walled metal-organic nanotube (SWMONT), namely, {[Cu3(µ3-OH)(H2O)3(Glytrz)3]⋅SiF6⋅8 H2O⋅X}∞ (1), (where X = disordered lattice water molecules) having a pore size as large as zeolites. Compound 1 was synthesized as crystals, as powder, or as layers by precipitation/electrodeposition. Mercury intrusion porosimetry demonstrates the ability of this material to store metallic mercury, after a pressure treatment, contrary to previous literature examples.

Study of the self-assembling of n-octylphosphonic acid layers on aluminum oxide.

The deposition of n-octylphosphonic acid on aluminum oxide was studied. The substrate was pretreated in order to achieve a root-mean-square roughness of <1 nm, a hydroxyl fraction of 30%, and a thickness of approximately 170 nm. It was proven using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) that, rather than a monolayer, an organic multilayer was formed. The growth mechanism was identified as a Stranski-Krastanov one. It was also shown that the use of AFM, probing the surface topography, is essential for a reliable quantification and interpretation of data obtained with XPS.

Systematic review of the chemical composition of contemporary dental adhesives.

Dental adhesives are designed to bond composite resins to enamel and dentin. Their chemical formulation determines to a large extent their adhesive performance in clinic. Irrespective of the number of bottles, an adhesive system typically contains resin monomers, curing initiators, inhibitors or stabilizers, solvents and sometimes inorganic filler. Each one of these components has a specific function. The aim of this article is to systematically review the ingredients commonly used in current dental adhesives as well as the properties of these ingredients. This paper includes an extensive table with the chemical formulation of contemporary dental adhesives.

Allergic contact granuloma due to palladium following ear piercing.

Two cases of sarcoidal-type allergic contact granuloma due to metals in ear piercing are presented, the first to palladium (Pd) only, and the second to Pd and possibly also to other metals. Both the patients developed papulonodular lesions at the helices following ear piercing, which after 3-4 weeks, became more granulomatous and very resistant to treatment. Indeed, repeated intralesional injections with corticosteroids produced only a temporary regression of the lesions. Biopsies from the persistent granulomatous lesions from the helices in both the patients and the positive test to Pd in case 2, 3 weeks after the patch-testing procedure, demonstrated epithelioid granulomas, with some multinucleate histiocytes surrounded by a lymphocytic-histiocytic infiltrate. Areas of fibrinoid necrosis were found in both the helix biopsies. An infectious pathology was excluded. Patch testing showed a strong positive reaction to Pd only in case 1 and to Pd and nickel in case 2. Chemical analysis of the earring of patient 1 confirmed the presence of Pd; however, analysis of the earrings of the second patient did not show the presence of Pd, but showed the presence of nickel and copper. Both the clinical and histological findings concur with some rarely reported similar observations in the literature.

Identification and isolation of a hyperphosphorylated, conformationally changed intermediate of human protein tau expressed in yeast.

Hyperphosphorylation and aggregation of protein tau are typical for neurodegenerative tauopathies, including Alzheimer's disease (AD). We demonstrate here that human tau expressed in yeast acquired pathological phosphoepitopes, assumed a pathological conformation, and formed aggregates. These processes were modulated by yeast kinases Mds1 and Pho85, orthologues of GSK-3beta and cdk5, respectively. Surprisingly, inactivation of Pho85 increased phosphorylation of tau-4R, concomitant with increased conformational change defined by antibody MC1 and a 40-fold increase in aggregation. Soluble protein tau, purified from yeast lacking PHO85, spontaneously and rapidly formed tau filaments in vitro. Further fractionation of tau by anion-exchange chromatography yielded a hyperphosphorylated monomeric subfraction, termed hP-tau/MC1, with slow electrophoretic mobility and enriched with all major epitopes, including MC1. Isolated hP-tau/MC1 vastly accelerated in vitro aggregation of wild-type tau-4R, demonstrating its functional capacity to initiate aggregation, as well as its structural stability. Combined, this novel yeast model recapitulates hyperphosphorylation, conformation, and aggregation of protein tau, provides insight in molecular changes crucial in tauopathies, offers a source for isolation of modified protein tau, and has potential for identification of modulating compounds and genes.

Changed conformation of mutant Tau-P301L underlies the moribund tauopathy, absent in progressive, nonlethal axonopathy of Tau-4R/2N transgenic mice.

Protein tau-3R/4R isoform ratio and phosphorylation regulates binding to microtubules and, when disturbed by aging or mutations, results in diverse tauopathies and in neurodegeneration. The underlying mechanisms were studied here in three transgenic mouse strains with identical genetic background, all expressing the tau-4R/2N isoform driven specifically in neurons by the thy1 gene promoter. Two strains, expressing human tau-4R/2N or mutant tau-4R/2N-P301L at similar, moderate levels, developed very different phenotypes. Tau-4R/2N mice became motor-impaired already around age 6-8 weeks, accompanied by axonopathy (dilatations, spheroids), but no tau aggregates, and surviving normally. In contrast, tau-P301L mice developed neurofibrillary tangles from age 6 months, without axonal dilatations and, despite only minor motor problems, all succumbing before the age of 13 months. The third strain, obtained by tau knock-out/knock-in (tau-KOKI), expressed normal levels of wild-type human tau-4R/2N replacing all mouse tau isoforms. Tau-KOKI mice survived normally with minor motor problems late in life and without any obvious pathology. Biochemically, a fraction of neuronal tau in aging tau-P301L mice was hyperphosphorylated concomitant with conformational changes and aggregation, but overall, tau-4R/2N was actually more phosphorylated than tau-P301L. Significantly, tau with changed conformation and with hyperphosphorylation colocalized in the same neurons in aging tau-P301L mice. Taken together, we conclude that excessive binding of tau-4R/2N as opposed to reduced binding of tau-P301L to microtubules is responsible for the development of axonopathy and tauopathy, respectively, in tau-4R/2N and tau-P301L mice and that the conformational change of tau-P301L is a major determinant in triggering the tauopathy.