The Optics of Human Skin

Administration of hematoporphyrin derivative i.v. followed by local exposure to red light has resulted in complete or partial response in 111 of 113 cutaneous or s.c. malignant lesions. Tumors treated have included carcinomas of the breast, colon, prostate, squamous cell, basal cell, and endometrium; malignant melanoma; mycosis fungoides; chondrosarcoma; and angiosarcoma. No type has been found to be unresponsive. In several cases complete clearing of chest wall metastatis has been achieved in treated areas. Deep-seated and pigmented tumors required a higher dose of drug for effective treatment than did the more superficial and nonpigmented lesions. A high therapeutic ratio between tumor and skin response has been obtained by allowing at least 3 days between drug injection and exposure to the therapeutic light for 2,5-mg/kg doses and at least a 4-day interval for 5.0-mg/kg doses.

https://cancerres.aacrjournals.org/content/canres/38/8/2628.full.pdf

Photoradiation therapy for the treatment of malignant tumors

DNA is taken as the target for skin cancer induced by ultraviolet light, and the known data on the sensitivity of DNA as a function of wavelength are summarized. The sun's spectrum at the surface of the earth and the DNA action spectrum are used to calculate the carcinogenic effectiveness as a function of wavelength. The most effective wavelengths at 30°N latitude are <305 nm, and a 1% change in atmospheric ozone results in a 2% change in the effective dose of ultraviolet light. Since both the basic biological and physical data are reasonably precise, the major requirement for a quantitative evaluation of the dose response relation for ultraviolet-induced skin cancer in man is better epidemiological data to compare with data from animal models.

https://www.pnas.org/content/pnas/71/9/3363.full.pdf

The wavelengths in sunlight effective in producing skin cancer: a theoretical analysis.

Sunscreens are used to provide protection against adverse effects of ultraviolet (UV)B (290-320 nm) and UVA (320-400 nm) radiation. According to the United States Food and Drug Administration, the protection factor against UVA should be at least one-third of the overall sun protection factor. Titanium dioxide (TiO2) and zinc oxide (ZnO) minerals are frequently employed in sunscreens as inorganic physical sun blockers. As TiO2 is more effective in UVB and ZnO in the UVA range, the combination of these particles assures a broad-band UV protection. However, to solve the cosmetic drawback of these opaque sunscreens, microsized TiO2 and ZnO have been increasingly replaced by TiO2 and ZnO nanoparticles (NPs) (<100 nm). This review focuses on significant effects on the UV attenuation of sunscreens when microsized TiO2 and ZnO particles are replaced by NPs and evaluates physicochemical aspects that affect effectiveness and safety of NP sunscreens. With the use of TiO2 and ZnO NPs, the undesired opaqueness disappears but the required balance between UVA and UVB protection can be altered. Utilization of mixtures of micro- and nanosized ZnO dispersions and nanosized TiO2 particles may improve this situation. Skin exposure to NP-containing sunscreens leads to incorporation of TiO2 and ZnO NPs in the stratum corneum, which can alter specific NP attenuation properties due to particle-particle, particle-skin, and skin-particle-light physicochemical interactions. Both sunscreen NPs induce (photo)cyto- and genotoxicity and have been sporadically observed in viable skin layers especially in case of long-term exposures and ZnO. Photocatalytic effects, the highest for anatase TiO2, cannot be completely prevented by coating of the particles, but silica-based coatings are most effective. Caution should still be exercised when new sunscreens are developed and research that includes sunscreen NP stabilization, chronic exposures, and reduction of NPs' free-radical production should receive full attention.

pdf/titanium-dioxide-and-zinc-oxide-nanoparticles-in-sunscreens-o35g5fi8hm.pdf

Titanium dioxide and zinc oxide nanoparticles in sunscreens: focus on their safety and effectiveness

The current status of tissue optics is reviewed, distinguishing among the cases of dominant absorption, dominant scattering, and scattering about equal to absorption. Previously published data as well as some current unpublished data on (human) stratum corneum, epidermis, and dermis are collected and/or (re)analyzed in terms of absorption coefficient, scattering coefficient, and anisotropy scattering factor. It is found that the individual skin layers show strongly forward scattering (anisotropy factors between 0.7 and 0.9). The absorption and scattering data show that for all wavelengths considered, scattering is much more important than absorption. Solutions to the transport equation for a multilayer skin model and finite beam laser irradiation that take this into account are not yet available. Hence, any quantitative dosimetry for skin treated with (laser) light is inaccurate. >

Skin optics

— The u.v. transmission characteristics of various epidermal specimens prepared by various methods were measured by a recording spectrophotometer and integrating spheres. Although suction or stretch and heat produced the most satisfactory specimens, transmission data obtained from all specimens were similar and generally resembled that reported by previous investigators. The important contribution of forward scattering to total transmitted light was demonstrated. Significant numbers of u.v. photons have been shown to penetrate to the dermis and papillary capillaries. Erythema was produced in vivo by monochromatic light filtered through epidermal specimens after exposure of skin to the quantity of u.v. anticipated by these data.

Penetration of epidermis by ultraviolet rays.

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Edward Yeargers

Author Tools

Chat about Author

Papers

Penetration of epidermis by ultraviolet rays.