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The role of glass as a barrier against the transmission of ultraviolet radiation: An experimental study

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Excessive exposure of the skin to sunlight may cause many symptoms and skin cancer. The aim was to measure the transmission of ultraviolet (UV) A and UVB radiation through glasses of different types, according to the distance from the light source. The baseline radiation from UVA and UVB sources was measured at different distances from the photometers. Next, the radiation from the same sources was measured at the same distances, but transmitted by different types of glass. The baseline values were compared with the results after protection using glass. Laminated glass totally blocked UVA radiation, while smooth ordinary glass transmitted the highest dose (74.3%). Greater thicknesses of glass implied less radiation transmitted, but without a significant difference. Green glass totally blocked UVA radiation, while blue glass transmitted the highest dose of radiation (56.8%). The presence of a sunlight control film totally blocked UVA radiation. All glasses totally blocked UVB radiation. The main characteristics of glass that make it a photoprotective agent are its type (especially laminated glass) and color (especially green), which give rise to good performance by this material as a barrier against the transmission of radiation.
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ORIGINAL ARTICLE
The role of glass as a barrier against the transmission of ultraviolet
radiation: an experimental study
Ida Duarte, Anita Rotter, Andrey Malvestiti & Mariana Silva
Department of Dermatology, Santa Casa de Miseric ´
ordia de Sa
˜o Paulo, Sao Paulo, Brazil
Key words:
glass; radiation; sunlight; ultraviolet rays
Correspondence:
Ida Duarte, Department of Dermatology, Santa Casa
de Miseric´ordia de Sa
˜o Paulo, Rua Monte Alegre,
523/101, Sao Paulo 05014-000, Brazil.
Tel: 155 11 3871 4018
Fax: 155 11 3871 4018
e-mail: idaduarte@terra.com.br
Accepted for publication:
25 February 2009
Conflicts of interest:
None declared.
Summary
Background/Purpose: Excessive exposure of the skin to sunlight may cause many symptoms
and skin cancer. The aim was to measure the transmission of ultraviolet (UV) A and UVB
radiation through glasses of different types, according to the distance from the light source.
Methods: The baseline radiation from UVA and UVB sources was measured at different
distances from the photometers. Next, the radiation from the same sources was measured at
the same distances, but transmitted by different types of glass. The baseline values were
compared with the results after protection using glass.
Results: Laminated glass totally blocked UVA radiation, while smooth ordinary glass
transmitted the highest dose (74.3%). Greater thicknesses of glass implied less radiation
transmitted, but without a significant difference. Green glass totally blocked UVA radiation,
while blue glass transmitted the highest dose of radiation (56.8%). The presence of a
sunlight control film totally blocked UVA radiation. All glasses totally blocked UVB radiation.
Conclusion: The main characteristics of glass that make it a photoprotective agent are its type
(especially laminated glass) and color (especially green), which give rise to good
performance by this material as a barrier against the transmission of radiation.
The effects on the skin from short- and long-term exposure
to ultraviolet (UV) radiation have already been extensively
dealt with in the literature (1–4). The main acute effects are
erythema, feelings of heat, edema, pain and pruritus. Other
events include late bronzing, thickening of the epidermis and
dermis, immunosuppression and vitamin D synthesis. On the
other hand, the chronic effects of this exposure consist of early
aging of the skin and carcinogenesis (5–7).
Nowadays, huge amounts of time in our daily lives are spent
in closed environments and in vehicles. Although the adverse
effects of UV radiation are well known, the function of the glass
for photoprotection has little coverage in the literature (8–10).
Recent advances in the glass industry have resulted in the
manufacture of window glass that provides broad protection
against UV radiation, but without causing losses in visible light
transmission. Some characteristics of glass material may have an
influence on the properties of protection against UV radiation,
such as the type, color, layers and coating of the glass (9).
Clear ordinary glass: This is transparent and colorless. Its main
characteristic is its capacity to provide protection against the
outside elements, while at the same time allowing transmission
of visible light into the interior. Depending on the thickness,
clear glass can transmit 490% of visible light (between 400 and
780 nm) and up to 83% of solar heat (9). It is also possible to
obtain imprinted glass by means of continuous melting of the
vitreous mass. Metal rollers are used to print a wide variety of
textures onto its surface.
Laminated glass: This is produced by associating two laminae of
glass with a layer of plastic (PVB – polyvinyl butyral), under heat
and pressure. Once the glass-and-plastic composite has been cast,
the result is a single lamina that is generally very similar to clear
ordinary glass. The benefit of laminated glass is that, if it breaks,
the fragments continue to adhere to the PVB layer, instead of
becoming scattered, thereby reducing the risk of accidents. PVB
filters approximately 99% of UV radiation without diminishing
the transmission of visible light (9).
Tempered glass: This is obtained by gradually heating the glass
and then abruptly cooling it in a vertical or a horizontal
tempering furnace. This is essentially a type of safety glass. In
the event of breakage, it shatters into very small pieces that are
not sharp (9).
Variation in the thickness of the glass has limited influence
with regard to blocking UV radiation, according to studies (9).
Tinted glass contains special colored components that absorb up
to 50% of the incident solar energy, thereby reducing the
undesired heat gain and transmitting less UV and visible light, in
comparison with ordinary glass (9). A study on the penetration
of UV radiation through car window glass demonstrated that this
transmission depended on whether the glass was tinted or not.
The results demonstrated that the colored sample completely
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removed the UVB spectrum and only allowed a small proportion
of UVA to pass (10).
UV transmission through vehicle window glass depends on
the type and tinting of the glass. For safety reasons, all
windscreens are made of laminated glass, which is able to filter
out practically all of the UVA. However, the glass for the side and
rear windows is normally tempered and therefore some of the
radiation is able to pass through. Plastic film to control sunlight,
which is often applied to these windows, results in 20–35%
visibility (transmission of visible light) and filters out the UVA of
wavelengths o380–370 nm (9).
The aim of the present study was to measure the transmission
of UVA and UVB radiation through samples of various types of
glass used in the windows of vehicles and houses, taking into
consideration the following variables: type, thickness and color
of the glass, application of sunlight control film and distance
between the light source and the glass.
Materials and methods
The following materials were used in the experiment:
(1) Glass
a. Window glass from built environments, with the following
variables: type (smooth ordinary, imprinted ordinary,
tempered and laminated), thickness (from 0.4 to 0.8 cm)
and color (colorless, green, wine, yellow and blue).
b. Window glass from vehicles, taking into consideration the
type (laminated and tempered) and application of sunlight
control film of the brand Insulfilm
TM
, type G50 (which
allows 50% visibility).
(2) Handisol
TM
UVA(315–400nm) and UVB(280–320nm)
emission sources, UVA-400C (315–400nm) and UVB(280
–320nm) photometers and goggles for protection against
UV radiation, all manufactured by National Biological
Corporation (Beachwood, OH, USA).
Firstly, the baseline radiation from the UVA emission source
was measured. This was measured after the source had been
switched on for 15 min, at distances of 0, 25, 50 and 100 cm,
without any glass as a barrier. The same procedure was then
followed using the UVB emission source.
The transmission of UVA and UVB radiation was then
measured through the different glass samples, taking the
following variables into consideration: type, thickness and color
of the glass, application of sunlight control film and distance
from the light source to the glass, up to the distance of 50 cm.
Lastly, the percentages of radiation transmitted through the glass
were calculated from the baseline values, thereby allowing these
materials to be evaluated as photoprotection agents.
Results
From the measurements of baseline radiation from the UVA
emission source, it was found that the initial radiation at the
distance of 0 cm from the photometer was 7.4 W/cm
2
; it was
0.6 W/cm
2
at 25 cm; 0.1 W/cm
2
at 50 cm; and no radiation was
detected by the photometer at 100 cm. UVB radiation without
glass protection gave the following results: 0.92 mW/cm
2
at
0 cm; 0.06 mW/cm
2
at 25 cm; 0.01 mW/cm
2
at 50 cm; and no
radiation was detected by the photometer at 100 cm.
In measuring the intensity of the radiation from the UVA
source, a considerable reduction in the quantity detected by the
photometer was observed as it was moved away from the source.
At a distance of 25 cm, the measurement was 0.6 W/cm
2
, which
corresponded to only 8% of the baseline UVA. This signifies a loss
of 92% of the irradiation when the measuring instrument was
moved away. With the photometer at a distance of 50cm, 0.1 W/cm
2
was detected, corresponding to 1.3% of the UVA radiation
transmitted by the source.
Tables 1–4 show the radiation detected by the photometer
after introducing the protective barriers of glass. With regard to
the types of glass used in buildings (Table 1), it was found that
laminated-glass totally blocked the UVA radiation, independent
of the distance from the source. At 0 cm from the source, smooth
ordinary glass was the type that transmitted the greatest amount
of radiation (74.3%), followed by tempered glass (71.6%) and
imprinted glass (44.6%). At a distance of 50 cm, all four samples
totally blocked the radiation.
Analysis of the smooth ordinary glass alone (Table 2) showed
that greater thicknesses blocked the passage of radiation more,
but without reaching statistical significance. At a distance of
50 cm, all the samples of smooth ordinary glass totally blocked
the radiation.
With regard to the color of imprinted ordinary glass (Table 3),
it was found that green glass totally blocked the UVA radiation,
independent of the distance from the source. At 0 cm from the
source, blue glass transmitted the greatest dose of radiation
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Table 1. Radiation from UVA emission source that was transmitted by different types of glass, according to distance from source
Type of glass
Radiation transmitted according to distance from source
0 cm (7.4 W/cm
2
) 25 cm (0.6 W/cm
2
) 50 cm (0.1 W/cm
2
)
W/cm
2
% W/cm
2
% W/cm
2
%
Smooth ordinary glass (4 mm) 5.5 74.3 0.4 66.6 0 0
Imprinted ordinary glass (4 mm) 3.3 44.6 0.3 50 0 0
Tempered glass (4 mm) 5.3 71.6 0.4 66.6 0 0
Laminated glass (8 mm) 0 0 0 0 0 0
Q2
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(56.8%), followed by colorless (36.5%), wine (31.1%) and
yellow (1.3%). Once again, at 50cm, all the samples analyzed
totally blocked the emitted radiation.
With regard to UVB radiation, for all the variables analyzed
(type, thickness and color of the glass), it was observed that the
samples totally blocked the UVB radiation at any distance from
the emission source.
Among the types of vehicle window glass (Table 4), it was
found that laminated glass totally blocked UVA radiation,
independent of the distance from the source. Tempered glass
for vehicle win dows transmitted 17 .6% of the radiation at 0 cm
from the source and totally blocked the radiation at greater
distances. Application of G50 sunlight control film to the
tempered glass totally blocked the UVA radiation emitted by
the source.
For all the variables analyzed (type of glass and application of
G50 sunlight control film), it was observed that the samples
totally blocked the UVB radiation, at any distance from the
emission source.
Discussion
Some studies have reported the importance of glass for blocking
UVB radiation and a certain wavelength range of UVA radiation (2).
Others have proven the importance of glass as a photoprotective
agent against undesirable biological effects. Bernstein et al.(8)
demonstrated that the decreased transmission of UV radiation
caused by glass drastically reduced the cytotoxicity measured using
the neutral red uptake photoprotection assay. However, little is
known about the influence of each characteristic of glass samples
on photoprotection (such as the type, thickness and color of the
glass and, in the case of vehicles, the application of sunlight control
film) and the impact of these effects on different skin phototypes.
In the present study, it was observed that all of the types of
glass decreased the transmission of UVA. Glass of laminated type
was the most efficient for totally blocking the UV radiation. This
may be explained by its production characteristics: an association
between two glass laminae and a layer of plastic (PVB), which
makes it an effective barrier against UVA (9).
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Table 2. Radiation from UVA emission source that was transmitted by smooth ordinary glass of different thicknesses, according to distance from source
Thickness of smooth
ordinary glass (cm)
Radiation transmitted according to distance from source
0 cm (7.4 W/cm
2
) 25 cm (0.6 W/cm
2
) 50 cm (0.1 W/cm
2
)
W/cm
2
% W/cm
2
% W/cm
2
%
0.2 5.6 75.7 0.5 83.3 0 0
0.3 5.5 74.3 0.4 66.6 0 0
0.4 5.5 74.3 0.4 66.6 0 0
0.5 4.7 63.5 0.4 66.6 0 0
0.6 4.5 60.8 0.4 66.6 0 0
0.8 3.8 51.4 0.3 50 0 0
1.0 3.8 51.4 0.3 50 0 0
Table 3. Radiation from UVA emission source that was transmitted by imprinted ordinary glass of different colors, according to distance from source
Color of imprinted ordinary glass
Radiation transmitted according to distance from source
0 cm (7.4 W/cm
2
) 25cm (0.6 W/cm
2
) 50cm (0.1 W/cm
2
)
W/cm
2
% W/cm
2
% W/cm
2
%
Colorless (3 mm) 2.7 36.5 0.2 33.3 0 0
Blue (3 mm) 4.2 56.8 0.3 50 0 0
Wine (3 mm) 2.3 31.1 0.2 33.3 0 0
Yellow (3 mm) 0.1 1.3 0 0 0 0
Green (3 mm) 0 0 0 0 0 0
Table 4. Radiation from UVA emission source that was transmitted by vehicle window glass of different types, according to distance from source
Type of glass
Radiation transmitted according to distance from source
0 cm (7.4 W/cm
2
) 25 cm (0.6 W/cm
2
) 50 cm (0.1 W/cm
2
)
W/cm
2
% W/cm
2
% W/cm
2
%
Tempered vehicle window glass (3 mm) 1.3 17.6 0 0 0 0
Tempered vehicle window glass with G50
protective film
000 00 0
Laminated glass (8 mm) 0 0 0 0 0 0
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The role of glass against the transmission of UV radiation
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The differences related to the UVA-laminated glass transmition
may be explained by the different manufacturers and the
technique utilized to obtain the measures. But as we know the
laminated glass is efficient to protect from the UVA radiation (9).
Some works published showed that the UV exposition through
car or home windows may favor the skin damage with the
windows opened, without the presence of glass protection
(11–13).
The transmission of radiation decreased with increasing
thickness of the glass, but not significantly, thus demonstrating
that this variable has little influence on blocking the radiation, in
comparison with the other variables analyzed. On the other
hand, the color of the glass had a huge influence on the
transmission of radiation. The sample of green glass totally
blocked the radiation and yellow glass only allowed the passage
of 1.3%, which may have occurred because of the properties of
the tinting pigments present. In glass manufacturing, colored
additives can be used, such as Fe
31
, which confers a brownish
yellow color, or a mixture of Fe
31
and Fe
21
, which provides a
green color. The Fe
21
ion absorbs light in the infrared region,
while Fe
31
absorbs light in the UV region. Thus, samples
containing Fe
31
in the tinting pigment are more efficient in
diminishing the transmission of UVA (14).
As already demonstrated in other studies, application of a
protective film to vehicle window glass gives rise to lower UVA
transmission than in the window glass alone (9). The results
from the present study demonstrated that the glass with the G50
sunlight control film totally blocked the UVA radiation.
The UVB radiation was totally blocked in the presence of all of
the glass samples used, at any distance from the emission source,
because its power of penetration is lower than that of UVA (2). It
can be affirmed that glass is an excellent filter for this type of
radiation, independent of its type, thickness or color.
Furthermore, the distance of the glass from the emission
source significantly influenced the quantity of baseline
radiation, such that the greater the distance, the lower the
irradiation and therefore the lower the transmission of UV
through the glass. This may be explained by the huge
dissipation of energy that occurs at greater distances under
environmental conditions.
Applying the above results to a situation within day-to-day
life, the UVB radiation incident on an individual inside a car with
closed windows is zero. Even in the case of UVA radiation, the
transmission would be insufficient to produce actinic damage,
given that not only does the glass block a large proportion of the
radiation but also small changes in the distance from the
emission source significantly decrease the irradiation.
Therefore, internal environments protected by glass can be
considered safe with regard to photoprotection. This observation
is also important within the field of occupational medicine, in
which the use of glass in vehicles used professionally would be a
preventive health measure for workers. Even taking into account
the radiation produced by artificial light bulbs within closed
environments, such as homes and offices, there is no risk of
phototoxicity. Even if these bulbs transmit some quantity of UV
radiation, this radiation is blocked by the glass of the light bulb
or the lamp itself, along with the distance between the source and
the individual.
It can be inferred that window glass may act as a photopro-
tective agent to prevent skin damage, by blocking the
transmission of UV radiation. This conclusion has a positive
impact on society, given that this material has a constant presence
in day-to-day life because of its versatility. The use of glass within
the fields of architecture, civil construction and the car industry
implies optimization of care relating to photoprotection.
There is a new type of glass called UV-blocking coated glass
(9). It is almost indistinguishable from standard clear glass and
blocks 498% of UV radiation while transmitting all the visible
light. It can be combined with a variety of other glass products,
often resulting in nearly complete UV blockage. This show the
industry’s concern for human health.
References
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˜es cl´ınicas.
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onigsmann H. Erythema and pigmentation. Photodermatol Photo-
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11. Moulin G, Thomas L, Vigneau M, et al. A case of unilateral
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... In a natural scenario, UV light is important for birds in relation to orientation, foraging, calibration of their circadian clock, and sexual selection [21]. In intensive systems, according to glass types, the full passage of UV light is blocked, but windows may be an alternative for providing some UV wavelengths to chickens [11,22,23]. ...
... The use of glass is opposed to the more common open-sided barns in Brazil. According to the glass type, some UV wavelength may be blocked [22,23]; however, the glass was a necessary resource to maintain the control on internal environmental conditions other than lighting between barn sides, to ensure that bird preference was based exclusively on illuminance, without any interference of other factors such as temperature or relative humidity. Approximately 3 4 of the window areas on the wall of the NAL side were shut by black curtains between 06:00 PM and 07:00 AM, and for the OAL side, the windows were totally closed by black curtains throughout the experimental period. ...
... The use of glass is opposed to the more common open-sided barns in Brazil. According to the glass type, some UV wavelength may be blocked [22,23]; however, the glass was a necessary resource to maintain the control on internal environmental conditions other than lighting between barn sides, to ensure that bird preference was based exclusively on illuminance, without any interference of other factors such as temperature or relative humidity. Approximately ¾ of the window areas on the wall of the NAL side were shut by black curtains between 06:00 PM and 07:00 AM, and for the OAL side, the windows were totally closed by black curtains throughout the experimental period. ...
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... In this group, the diet contained 0.67% phosphorus, 1% calcium and less than 8 IU vitamin D3/kg of diet 36 . The mice were maintained under UV restriction conditions 37 . Vitamin D deficient/normo-calcemia (VD − Ca + ) group: mice were treated with 32 ng paricalcitol 3 times per week for one week. ...
... In this group, the diet contained 1.25% phosphorus, 2% calcium, 20% lactose and less than 8 IU vitamin D3/kg of diet 36 . The mice were maintained under UV restriction conditions 37 . Vitamin D Normal/hypo-calcemia (VD + Ca − ): each mice was treated with 0.02 mg of zoledronic acid 3 times per week for four weeks. ...
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... The investigation of the impact strength, compressive strength, and modulus of elasticity tests were performed. These tests were to show how the additive will withstand weather conditions, reduce degradation of the interstitial layer and resistance change in colour, improve transparency properties, and make polymer material more cohesive to prevent polymer chains from breaking [21]. In addition, another test is to expose these samples to the photovoltaic light using electric xenon light 2.5 W/m² and normal temperature up to 36 ° C in the optical spectrometer. ...
... To detect the change in the mechanical properties after exposure for different periods equivalent to years of service of the material used, the material supported by a lamp (xenon) of 2.5 W/m² using the spectrometer (prism) at the following exposures shown in Table 1. The exposure period is equivalent to years of service life for the materials used to demonstrate their tolerance to sunlight conditions and not to change their mechanical and physical properties [21]. ...
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The safety of automobiles has been the concern of billions of people who used cars for various purposes. The windshield is probably the first issue that automobiles companies must keep into consideration. This research provides very important insight information regarding enhancing the mechanical properties of the windshield while monitoring transparency. The glass used in this research and the subsequent preparation and testing were performed according to the Standard Specification for Laminated Architecture Flat Glass (ASTM C1172) and Glass in Building-Laminated glass and Laminated Safety (ISO 12543). Three groups of a double-layered glass laminated with a resin of polycarbonates at 5%, 10%, and 15% volume fraction were prepared and tested for the mechanical properties of the impact value, compression test, and modulus of elasticity. The results have shown that the 5%-polycarbonates has the maximum effect by enhancing the mechanical properties by 21.9%, 12.6%, and 15.9%, respectively. The mechanical properties of only those samples of the 5% polycarbonates were further investigated after UV exposure at 30 h, 60 h, and 90 h. The results showed that the mechanical properties were deteriorated; yet, showing various effects of exposure time. The impact value was reduced by 3%, 24%, and 35% after exposure of 30 h, 60 h, and 90 h, respectively. The compression strength and modulus of elasticity were enhanced by 17% after 30 h exposure while the modulus enhanced by 16 % after 60 h exposure-both before deteriorating. SEM images have shown that the effect of UV effect has caused better smoothness as the UV radiation increased from 30 h to 90 h.
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... Despite recent advancement in UV-protection technology and materials [34][35][36], alternative means for UVA protection are still in high demand. New protective strategies have to be tested for their efficiency to shield against UV-induced damage without reducing its therapeutic potential. ...
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... As a result, vitD 3 requirements are supplemented in the diet. Although windows may be incorporated into poultry houses, they may not transmit UVB for vitD 3 synthesis in broilers (Duarte et al., 2009). Additionally, continuous artificial light illuminations provided are weak ultraviolet (UV) emitters (Lewis and Morris, 1998). ...
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... The wavelength of UV blocking of the laminated glass with the PVB interlayer is 380 nm. The ultraviolet blocking wavelength of visible ion laminated glass is 310nm, and the ultraviolet blocking of laminated glass can act as a barrier to human skin [40]. The UV barrier rate of two exhibited samples is 99.9%. ...
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... Ultraviolet transmittance (UVT) indicates the percentage of incident ultraviolet (UV) radiation that passes through the glazing (Duarte et al., 2009). The typical transmission of UV through clear single glazing is 80% (Carmody et al., 2000, Saridar, 2004. ...
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Drug-induced photosensitivity (DIP) is a common cutaneous adverse drug reaction, resulting from the interaction of ultraviolet radiations, mostly ultraviolet A, with drugs. DIP includes phototoxicity and photoallergy. A phototoxic reaction is obtained when topical and systemic drugs or their metabolites absorb light inducing a direct cellular damage, while a photoallergic reaction takes place when the interaction between drugs and ultraviolet radiations causes an immune cutaneous response. Clinically, phototoxicity is immediate and appears as an exaggerated sunburn, whereas photoallergy is a delayed eczematous reaction. DIP may show several clinical subtypes. In this mini-review we report the pathogenetic mechanisms and causative drugs of DIP. We offer a detailed description of DIP clinical features in its classical and unusual subtypes, such as hyperpigmentation/dyschromia, pseudoporphyria, photo-onycolysis, eruptive teleangiectasia, pellagra-like reaction, lichenoid reaction, photodistributed erythema multiforme and subacute/chronic cutaneous lupus erythematosus. We described how physicians may early recognize and manage DIP, including diagnostic tests to rule out similar conditions. We made suggestions on how to improve sun exposure behaviors of patients at risk of DIP by means of an aware use of sunscreens, protective clothing and recent technologic tools. We highlighted the lack of sun safety programs addressed to patients at risk of DIP, who need a formal education about their condition.
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Phototherapy has been used to treat a large variety of dermatoses since the past century. It is classified according to the type of irradiation (UVA or UVB). Phototherapy is indicated for all types of inflammatory and chronic skin diseases, such as vitiligo, psoriasis, parapsoriasis, cutaneous T-cell lymphomas and chronic eczemas, with good therapeutic results. It can be used as monotherapy or associated with others drugs, such as retinoids, methotrexate and cyclosporine, aiming to reduce length of treatment and doses. Like other treatments, phototherapy has some limitations - it requires specific equipment, patient's compliance, has restricted indications and leads to cumulative UV doses. The therapy must be performed with strict follow-up to obtain effective therapeutic response and few adverse effects.
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Phototherapy uses repeated controlled ultraviolet exposures to alter cutaneous biology, aiming to induce remission or control progression of skin diseases. This is an overview of the current practice of phototherapy applying ultraviolet radiation alone, in combination with photosensitizers or other medications. The mechanisms of action, the most accepted indications, regimens of prescription and side effects will also be discussed.
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Bottom ash has been used as raw material to glass and glass ceramic production because it is a source of SiO2 and Al2O3. However, the high concentration of iron (about 10% wt.) difficulty the control of the nucleation and the crystallization processes. The iron content was reduced by magnetic process, where the magnetite phase was mainly removed. In order to compare glass ceramics obtained from original and low iron bottom ashes, microstructural and dilatometric characterizations were performed.
Chapter
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Full textFull text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (241K), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References. 18 Selected References These references are in PubMed. This may not be the complete list of references from this article. Marks R, Selwood TS. Solar keratoses. The association with erythemal ultraviolet radiation in Australia. Cancer. 1985 Nov 1;56(9):2332–2336. [PubMed]