Prolonged Sunlight Exposure Research Articles

Recycling and breakdown photodegradation processes cost of BEN-TiQD via different photodegradation processes of Brilliant Green S dye and industrial effluents

The development of efficient photocatalytic materials for environmental remediation is of paramount importance. This study reports the synthesis and characterization of novel bentonite-titanium dioxide quantum dot (BEN-TiQD) nanocomposites for the photodegradation of Brilliant Green S, a prominent industrial pollutant. The nanocomposites were prepared via a co-precipitation method, ensuring uniform dispersion of TiO2 nanoparticles on the bentonite (BEN) surface, followed by heat treatment to achieve optimal crystallinity and surface properties. Comprehensive characterization techniques, including FTIR, XRD, SEM, BET surface area analysis, and optical spectroscopy, were employed to elucidate the structural, morphological, and photophysical characteristics of the composites. The BEN-TiQD nanocomposites exhibited an augmented surface area of 277.75 m2/g, surpassing BEN alone by more than threefold, and an intermediate bandgap of 3.17 eV, rendering them suitable for visible light absorption and photocatalytic applications. The photocatalytic efficacy of BEN-TiQD was evaluated by monitoring the degradation of Brilliant Green S under various operational parameters. The nanocomposites demonstrated superior photocatalytic performance, with a rate constant of 22.24 × 10−3 s−1, significantly only lower than TiQD (28.32 × 10−3 s−1) by nearly about 21.5 %. The enhanced activity was attributed to the quantum size effect of the incorporated TiO2 quantum dots, optimizing light absorption and charge separation. Mechanistic studies revealed the generation of reactive oxygen species, particularly hydroxyl radicals, as the primary drivers of dye degradation. The reusability of BEN-TiQD was evaluated through multiple photocatalytic cycles, exhibiting remarkable stability for up to six consecutive cycles. However, a gradual decline in photodegradation efficiency was observed after prolonged sunlight exposure, likely due to particle agglomeration and reduced surface area. This research contributes to the field of environmental remediation by developing a novel composite material that synergistically combines the adsorptive properties of BEN with the photocatalytic capabilities of titanium dioxide quantum dots. The findings pave the way for further exploration and optimization of these composites for sustainable and efficient treatment of industrial dyes and effluents, addressing critical environmental challenges.

Screening the release of chemicals and microplastic particles from diverse plastic consumer products into water under accelerated UV weathering conditions

Photodegradation of plastic consumer products is known to accelerate weathering and facilitate the release of chemicals and plastic particles into the aquatic environment. However, these processes are complex. In our presented pilot study, eight plastic consumer products were leached in distilled water under strong ultraviolet (UV) light simulating eight months of Central European climate and compared to their respective dark controls (DCs). The leachates and formed plastic particles were exploratorily characterized using a range of chemical analytical tools to describe degradation and leaching processes. These techniques covered (a) microplastic analysis, showing substantial liberation of plastic particles further increased under UV exposure, (b) non-targeted mass spectrometric characterization of the leachates, revealing several hundreds of chemical features with typically only minor agreement between the UV exposure and the corresponding DCs, (c) target analysis of 71 organic analytes, of which 15 could be detected in at least one sample, and (d) metal(loid) analysis, which revealed substantial release of toxic metal(loid)s further enhanced under UV exposure. A data comparison with the US-EPA’s ToxVal and ToxCast databases showed that the detected metals and organic additives might pose substantial health and environmental concerns, requiring further study and comprehensive impact assessments.

Postmortem Tanning: An Unusual Postmortem Event.

A variety of changes, many predictable and others more aberrant, occur during the postmortem interval. A number of these changes are largely influenced by various environmental conditions. We describe 3 cases of an unusual postmortem change associated with prolonged sunlight exposure in both frozen and nonfrozen individuals. In each case, very well-delineated, dark tanning lines were present where clothing or another object blocked sunlight. This change appears distinct from mummification and scant literature references that describe a tanned skin transformation in cases associated with burials in high salt-containing bogs. Collectively, the cases highlight a novel postmortem phenomenon known as postmortem tanning. The potential mechanism(s) of this change is discussed within the context of known observations. Increased recognition and knowledge of postmortem tanning are exceedingly important in assessing how this change may assist in postmortem scene analysis.

What was the Epidemiology and Global Burden of Disease of Hip Fractures From 1990 to 2019? Results From and Additional Analysis of the Global Burden of Disease Study 2019.

Hip fractures are associated with a high risk of death; among those who survive a hip fracture, many experience substantial decreases in quality of life. A comprehensive understanding of the epidemiology and burden of hip fractures by country, age, gender, and sociodemographic factors would provide valuable information for healthcare policymaking and clinical practice. The Global Burden of Disease (GBD) study 2019 was a global-level study estimating the burden of 369 diseases and injuries in 204 countries and territories. An exploration and additional analysis of the GBD 2019 would provide a clearer picture of the incidence and burden of hip fractures. Using data from the GBD 2019, we asked, (1) What are the global, regional, and national incidences of hip fractures, and how did they change over a recent 30-year span? (2) What is the global, regional, and national burden of hip fractures in terms of years lived with disability, and how did it change over that same period? (3) What is the leading cause of hip fractures? (4) How did the incidence and years lived with disability of patients with hip fractures change with age, gender, and sociodemographic factors? This was a cross-sectional study. Participant data were obtained from the GBD 2019 ( http://ghdx.healthdata.org/gbd-results-tool ). The GBD study is managed by the WHO, coordinated by the Institute of Health Metrics and Evaluation, and funded by the Bill and Melinda Gates Foundation. It estimates the burden of disease and injury for 204 countries by age, gender, and sociodemographic factors, and can serve as a valuable reference for health policymaking. All estimates and their 95% uncertainty interval (UI) were produced using DisMod-MR 2.1, a Bayesian meta-regression tool in the GBD 2019. In this study, we directly pulled the age-standardized incidence rate and years lived with disability rate of hip fractures by location, age, gender, and cause from the GBD 2019. Based on these data, we analyzed the association between the incidence rate and latitude of each country. Then, we calculated the estimated annual percentage change to represent trends from 1990 to 2019. We also used the Spearman rank-order correlation analysis to determine the correlation between the incidence or burden of hip fractures and the sociodemographic index, a composite index of the income per capita, average years of educational attainment, and fertility rates in a country. Globally, hip fracture incidences were estimated to be 14.2 million (95% UI 11.1 to 18.1), and the associated years lived with disability were 2.9 million (95% UI 2.0 to 4.0) in 2019, with an incidence of 182 (95% UI 142 to 231) and 37 (95% UI 25 to 50) per 100,000, respectively. A strong, positive correlation was observed between the incidence rate and the latitude of each country (rho = 0.65; p < 0.001). From 1990 to 2019, the global incidence rate for both genders remained unchanged (estimated annual percentage change 0.01 [95% confidence interval -0.08 to 0.11]), but was slightly increased in men (estimated annual percentage change 0.11 [95% CI 0.01 to 0.2]). The years lived with disability rate decreased slightly (estimated annual percentage change 0.66 [95% CI -0.73 to -0.6]). These rates were standardized by age. Falls were the leading cause of hip fractures, accounting for 66% of all patients and 55% of the total years lived with disability. The incidence of hip fractures was tightly and positively correlated with the sociodemographic index (rho 0.624; p < 0.001), while the years lived with disability rate was slightly negatively correlated (rho -0.247; p < 0.001). Most hip fractures occurred in people older than 70 years, and women had higher incidence rate (189.7 [95% UI 144.2 to 247.2] versus 166.2 [95% UI 133.2 to 205.8] per 100,000) and years lived with disability (38.4 [95% UI 26.9 to 51.6] versus 33.7 [95% UI 23.1 to 45.5] per 100,000) than men. Hip fractures are common, devastating to patients, and economically burdensome to healthcare systems globally, with falls being the leading cause. The age-standardized incidence rate has slightly increased in men. Many low-latitude countries have lower incidences, possibly because of prolonged sunlight exposure. Policies should be directed to promoting public health education about maintaining bone-protective lifestyles, enhancing the knowledge of osteoporosis management in young resident physicians and those in practice, increasing the awareness of osteoporosis screening and treatment in men, and developing more effective antiosteoporosis drugs for clinical use. Level III, prognostic study.

Living Fungi in an Opencast Limestone Mine: Who Are They and What Can They Do?

Opencast limestone mines or limestone quarries are considered challenging ecosystems for soil fungi as they are highly degraded land with specific conditions, including high temperature, prolonged sunlight exposure, and a lack of organic matter, moisture, and nutrients in soil. In such ecosystems, certain fungi can survive and have a crucial function in maintaining soil ecosystem functions. Unfortunately, we know very little about taxonomic diversity, potential functions, and the ecology of such fungi, especially for a limestone quarry in a tropical region. Here, we characterized and compared the living soil fungal communities in an opencast limestone mine, including mining site and its associated rehabilitation site (9 months post-rehabilitation), with the soil fungal community in a reference forest, using the amplicon sequencing of enrichment culture. Our results showed that living fungal richness in the quarry areas was significantly lower than that in the reference forest, and their community compositions were also significantly different. Living fungi in the mining sites mostly comprised of Ascomycota (Eurotiomycetes and Sordariomycetes) with strongly declined abundance or absence of Basidiomycota and Mucoromycota. After nine months of rehabilitation, certain taxa were introduced, such as Hypoxylon spp. and Phellinus noxius, though this change did not significantly differentiate fungal community composition between the mining and rehabilitation plots. The majority of fungi in these plots are classified as saprotrophs, which potentially produce all fifteen soil enzymes used as soil health indicators. Network analysis, which was analyzed to show insight into complex structures of living fungal community in the limestone quarry, showed a clear modular structure that was significantly impacted by different soil properties. Furthermore, this study suggests potential taxa that could be useful for future rehabilitation.

Photolyase Production and Current Applications: A Review.

The photolyase family consists of flavoproteins with enzyme activity able to repair ultraviolet light radiation damage by photoreactivation. DNA damage by the formation of a cyclobutane pyrimidine dimer (CPD) and a pyrimidine-pyrimidone (6-4) photoproduct can lead to multiple affections such as cellular apoptosis and mutagenesis that can evolve into skin cancer. The development of integrated applications to prevent the negative effects of prolonged sunlight exposure, usually during outdoor activities, is imperative. This study presents the functions, characteristics, and types of photolyases, their therapeutic and cosmetic applications, and additionally explores some photolyase-producing microorganisms and drug delivery systems.

Toward Experimental Heat–Health Early Warning in Africa

Abstract Heat is one of the most serious hazards in the world as it affects human health and is extremely dangerous to vulnerable populations such as the elderly, people with preexisting cardiovascular or respiratory conditions, and even healthy people with prolonged sunlight exposure during heat waves. As the globe has warmed over the past several decades, extreme heat has become more frequent and intense than ever before, and Africa, especially the Sahel in West Africa, is one of the regions of the world where heat is a major public health concern exacerbated by livelihood activities during the heat season. Yet, there is a major gap in monitoring and forecasting heat waves in Africa. This paper describes NOAA’s role in enabling heat–health early warning in Africa, working with meteorological services and health professionals. Emphasis is on real-time heat wave forecasting at week 2, including the postprocessing of the NCEP model outputs, and providing the information to the meteorological services in Africa to serve as guidance in national heat wave forecasts. In addition, the paper describes the end-to-end process of heat hazard outlooks and translating the forecasts into early action and early planning to reduce heat risk to human health. Furthermore, the paper addresses the very important aspect of capacity development tailored at enhancing forecasters’ skills to prepare and issue heat wave forecasts and training of a cadre of health professionals to work with meteorologists to coproduce heat–health bulletins and to issue heat–health early warnings.

Erythropoietic Protoporphyria: Phase 2 Clinical Trial Results Evaluating the Safety and Effectiveness of Dersimelagon (MT-7117), an Oral MC1R Agonist

Introduction Erythropoietic Protoporphyria (EPP) or X-Linked Protoporphyria (XLP) are inborn errors of heme biosynthesis caused by the abnormal accumulation of erythrocyte protoporphyrin IX (ePPIX). These protoporphyrias are characterized by excruciating painful attacks on prolonged sunlight exposure. Before the onset of phototoxic pain, patients experience characteristic prodromal symptoms which serves as a warning signal to avoid further sun exposure. Of note, patients with higher ePPIX levels report shorter times to symptoms compared to patients with lower median ePPIX levels (JAMA Derm, 2017; 153). Here we report the safety and effectiveness of Dersimelagon (MT-7117), a novel, orally-administered, small molecule, selective melanocortin-1 receptor (MC1R) agonist that increases skin melanin without sun exposure and is being developed to increase light tolerance in EPP/XLP patients. Results of the primary, secondary efficacy endpoints, and post-hoc subgroup analyses evaluating effects of baseline ePPIX levels on treatment response will be presented. Methods The MT-7117-A01 (ENDEAVOR) study was a Phase 2, multi-center, randomized, placebo-controlled study with a 16-week double-blind treatment period. A total of 102 EPP/XLP patients were randomized to 3 groups: placebo once daily (QD) (n=35 [31 EPP/4 XLP]), MT-7117 100 mg QD (n=33 [31 EPP/2 XLP]), and MT-7117 300 mg QD (n=34 [31 EPP/3 XLP]). Results of the primary endpoint, increase in the average daily time (min) to first prodromal symptom during sunlight exposure, and secondary endpoints including 1) average daily duration of sunlight exposure without prodromal symptoms, 2) total number of sunlight exposure episodes with prodromal symptoms, and 3) total number of pain events, and post-hoc subgroup analyses evaluating baseline median ePPIX levels are presented here. Safety and tolerability were also assessed. Results There was a significant improvement in average daily time (&amp;gt;50 min) to first prodromal symptom [the primary endpoint] associated with sunlight exposure in subjects treated with MT-7117 100 mg (p=0.008) or 300 mg (p=0.003) compared to placebo at Week 16. Multiple secondary endpoints supported primary endpoint. There was a significant increase in average daily minutes of sunlight exposure without prodromal symptoms at Week 16 in 100 mg (p=0.009) and 300 mg (p=0.004) treated subjects compared to placebo, with an increased average exposure time without prodromal symptoms of ~50 min in MT-7117 subjects at both doses compared to placebo. There was also a 40% reduction in the total number of sunlight exposure episodes with prodromal symptoms in 100 mg (p=0.019) and 300 mg (p=0.006) subjects compared to placebo. There was a significant decrease in the total number of pain events reported in 100 mg (p=0.027, 60% reduction) and 300 mg (p=0.028, 50% reduction) subjects compared to placebo. The post-hoc subgroup analysis evaluating the effects of baseline ePPIX levels in subjects grouped based on the baseline median ePPIX level of 1981 µg/dL. There was a statistically significant increase in average daily time to first prodromal symptom in the subgroup with ePPIX levels ≥1981 µg/dL receiving 100 mg (p=0.020) and 300 mg (p=0.003) compared to placebo. A trend to beneficial effect was also observed for the subgroup of subjects with ePPIX levels &amp;lt;1981 µg/dL receiving 100 mg (p=0.180) and 300 mg (p=0.216) compared to placebo. MT-7117 had an acceptable safety and tolerability profile. The most common treatment-related treatment emergent adverse reactions were nausea (27.9%), ephelides (23.5%), and skin hyperpigmentation (20.6%). Conclusion The results of the primary efficacy endpoint and multiple secondary endpoints in this Phase 2 study indicate that the oral, MC1R agonist dersimelagon was efficacious after 16 weeks of treatment in increasing symptom-free light exposure in patients with EPP or XLP at doses of 100 and 300 mg QD and showed an acceptable safety and tolerability profile. The post-hoc analyses showed more profound and statistically significant efficacy at both doses for the subgroup with higher baseline median ePPIX levels. Disclosures Balwani: Alnylam Pharmaceuticals: Consultancy, Honoraria, Research Funding; Recordati Rare Diseases: Consultancy, Honoraria, Other: Disease information video recording. Anderson:Alnylam Pahrmaceuticals: Consultancy; Recordati Rare Diseases: Consultancy; Mitsubishi Tanabe Pharma: Consultancy.

Fabrication and investigation of 3D tuned PEG/PEDOT: PSS treated conductive and durable cotton fabric for superior electrical conductivity and flexible electromagnetic interference shielding

Promotions of conducting e-textiles are drawing attention for mitigating electromagnetic radiation pollution. Probably it is a huge challenge to gain long-term durable and stable fabric for all-weather outdoor application. In this work, a facile dip coating design has been adopted to fabricate PEG/PEDOT: PSS treated fabric. The high electrical conductivity of 51.0 S cm−1 and EMI SE of 46.8 dB (in X-band) were achieved by only 20 dipping cycles (thickness ∼ 0.38 mm), whereas the optimum conductivity and shielding were found to be 82.7 S cm−1 and 65.6 dB at 25 dipping cycles. According to the AFM, XPS, SAXS and FTIR characterization, the enhancement in electrical conductivity was found to be the phase separation between PEDOT and PSS followed by the charge screening phenomena. The exclusive “void-filler” inclusion in the whole fabric also has been evaluated in order to correlate their microstructure (both 2D and 3D) along with the desirable conducting features. Remarkably, the conducting network remains flexible even after prolonged sunlight exposure, thermal air ageing, repeated bending with twisting, peeling with single sided tape, boiling with water, and different organic solvents which proves its versatile mechanical and chemical robustness. Such long term deformations exhibit above 95% retention of EMI SE which offers a promising approach to fabricate a futuristic e-textiles which can address long-term exposure towards the extreme environmental conditions (both wet and dry media).

Sternectomy for Treating Advanced Non-Melanoma Skin Cancer

Introduction Skin cancer is a rare indication of sternectomy. Our goal is to report the clinical course of seven patients who underwent sternectomy for skin cancer. Methods The survey data were collected from medical records of patients treated between 2008 and 2018 at Ceará Cancer Institute. Results All patients had prolonged sunlight exposure and average disease time of two years and age of 60 years. Most patients recovered favorably after treatment with prolonged survival. Conclusion Sternectomy remains an option with curative purposes for locally advanced skin cancer.

An approach to prepare mechanically robust full IPN strengthened conductive cotton fabric for high strain tolerant electromagnetic interference shielding

High mechanical strength coated conductive flexible cotton fabric with electrical and electromagnetic interference (EMI) shielding properties has been developed by low cost and facile one-pot fabrication technique. Herein, polyvinyl alcohol (PVA) and natural rubber latex (NRL) have been judicially amalgamated with specialty conducting black. The polymer blends were not only physically mixed but also covalently interwoven by means of inter-penetrating polymeric network (IPN) approach. The morphological study combined with electron microscopy and 3D micro-computed tomography reveals uniform and flexible conductive network formation. The coated fabric was tested under rigorous environmental and practical factors/stresses (e.g., prolonged sunlight exposure, flexibility under liquid nitrogen, abrasion, water durability and detergent action) which provide information regarding the sustainability of the fabric for outdoor applications. Besides the surprising improvement in uniaxial mechanical property, the unique coated fabric also shows high electrical attributes. Such long-term cyclic deformation study shows ∼95% retention of EM performance due to the flexible network structure. The measurements of complex permittivity and impedance matching coefficient also support the absorption capacity of the coated fabrics. The biphasic polymeric system (here PVA and NRL) synergistically improves the dispersion of fillers even at high loading (i.e., stabilization), anti-leaching feature and surprisingly the tensile property. For extensive functionality, the EMI shielding of the coated fabric was experimented under those simulated practical forces, which can make them useful as a high performing flexible wearable fabric against EM radiation pollution.

Does hypothyroidism augment sun-induced skin damage?

ABSTRACTObjectives: We investigated the mutual effects of overt hypothyroidism and prolonged sunlight exposure on free radical accumulation and oxidative skin damage.Methods: Free radical accumulation was evaluated by monitoring the transformation of 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) into MTT-formazan. The pro-oxidant enzymes xanthine oxidase (XO) and NADPH-diaphorase were measured in the skin. XO activity was estimated based on the yield of uric acid, while NADPH-diaphorase reactivity was monitored histochemically as an indirect marker of nitric oxide synthase and nitric oxide activity. Cellular damage was determined by malondialdehyde formation, a marker for lipid peroxidation.Results: In the skin of both euthyroid and hypothyroid animals, solar simulated ultraviolet irradiance increased the activity of XO and the NADPHdiaphorase reactivity as a protective response to formation of free radicals, such as reactive oxygen or nitrogen species. These pro-oxidant enzymes diminished in hypothyroid rats. Accumulation of the same amount of free radicals led to similar peroxidation in both hypothyroid and irradiated euthyroid rats. Hypothyroid skin after UV-exposure showed even greater lipid peroxidation.Discussion: The hypothyroid state could be a risk factor for enhanced oxidative skin damage in chronic photo-exposed skin due to oxidative stress. The lipid peroxidation is one of the major pathways by which photo-oxidative stress promotes photocarcinogenesis and photo-aging.

Photoinhibition of germination in grass seed – Implications for prairie revegetation

Germination photoinhibition is not a recognized cause of revegetation failure; yet prolonged sunlight exposure can inhibit germination of several grass species. This research addressed susceptibility to photoinhibition of selected native grass species used to restore Canadian prairies, and reclamation treatments to alter environmental conditions in order to release seeds from photoinhibition. Under laboratory conditions effects of photoinhibition were tested on the ability of seeds to germinate at low water potential and effects of daily alternating temperatures and nitrates to break photoinhibition. Whether surficial mulch can release seeds from photoinhibition was assessed in a field experiment. Germination photoinhibition was evident in Festuca hallii and Koeleria macrantha seeds even under very low irradiances. The prolonged exposure to light decreased germination rates and ability of seeds to germinate at low water potentials. Daily fluctuating temperatures released a fraction of Bromus carinatus and Elymus trachycaulus seeds from photoinhibition yet did not improve F. hallii or K. macrantha germinability. Nitrates failed to break seed photoinhibition in all species tested. In the field experiment, mulched F. hallii seeds (covered with an erosion control blanket) showed a tenfold increase in germination percentages relative to seeds exposed to direct sunlight, indicating the facilitative effects of mulching on attenuation of the light environment. We conclude that germination photoinhibition as a cause of emergence failures in land reclamation where seed is broadcast or shallow seeded should be recognized and germination photoinhibition included in the decision making process to select revegetation seeding techniques.

Skin Protection Against UVA-Induced Iron Damage by Multiantioxidants and Iron Chelating Drugs/Prodrugs

In humans, prolonged sunlight exposure is associated with various pathological states. The continuing drive to develop improved skin protection involves not only approaches to reduce DNA damage by solar ultraviolet B (UVB) but also the development of methodologies to provide protection against ultraviolet A (UVA), the oxidising component of sunlight. Furthermore identification of specific cellular events following ultraviolet (UV) irradiation is likely to provide clues as to the mechanism of the development of resulting pathologies and therefore strategies for protection. Our discovery that UVA radiation, leads to an immediate measurable increase in 'labile' iron in human skin fibroblasts and keratinocytes provides a new insight into UVA-induced skin damage, since iron is a catalyst of biological oxidations. The main purpose of this overview is to bring together some of the new findings related to mechanisms underlying UVA-induced iron release and to discuss novel approaches based on the use of multiantioxidants and light-activated caged-iron chelators for efficient protection of skin cells against UVA-induced iron damage.

Photooxidation of dyed styrene-butadiene and natural rubbers

Dyed natural rubber (NR) and styrene-butadiene rubber (SBR) designed for outdoor applications were exposed to accelerated artificial aging in xenon light. The aging results in the deterioration of the properties of the exposed surface material. The ability of dyed polymers to withstand prolonged sunlight exposure without fading or undergoing any physical deterioration is largely determined not only by the photochemical characteristics of the absorbing dyestuff itself but also by the polymer structure and fillers. Results indicate that dyed filled NR and SBR samples behave differently during photooxidation. The photodegradation products were observed by Fourier transform infrared spectroscopy (FTIR) to characterize the changes occurring in the polymer matrix during UV aging. The fading of the dyed polymers was found to be promoted in the NR sample. Moreover, the effects of photooxidation on the dyed SBR and NR materials were assessed by the formation of cracks and the thickness of the degraded area. The degradation thickness is more important for the NR sample than for the SBR one according to environmental scanning electron microscopy (ESEM) observations. For the NR sample, cracks appear initially at the surface and then grow through the thickness of the specimen, while for the SBR sample cracks are small and discontinuous.

Study of Polymer Material Aging by Laser Mass Spectrometry, UV-Visible Spectroscopy, and Environmental Scanning Electron Microscopy

Dyed natural rubber (NR) and styrene butadiene rubber (SBR), designed for outdoor applications, were exposed to an accelerated artificial aging in xenon light. The aging results in the deterioration of the exposed surface material properties. The ability of dyed polymers to withstand prolonged sunlight exposure without fading or undergoing any physical deterioration is largely determined not only by the photochemical characteristics of the absorbing dyestuff itself but also by the polymer structure and fillers. Results obtained by laser mass spectrometry, UV-visible spectroscopy, and environmental scanning electron microscopy indicate that dyed filled NR and SBR samples behave differently during the photo-oxidation. The fading of the dyed polymers was found to be promoted in the NR sample. This can be correlated with LDI-FTICRMS results, which show the absence of [M-H]− orange pigment pseudomolecular ion and also its fragment ions after aging. This is confirmed by both EDX and UV/Vis spectroscopy. EDX analysis indicates a concentration of chlorine atoms, which can be considered as a marker of orange pigment or its degradation products, only at the surface of SBR flooring after aging. Reactivity of radicals formed during flooring aging has been studied and seems to greatly affect the behavior of such organic pigments.

Cyclooxygenase-2 Immunoreactivity in Equine Ocular Squamous-Cell Carcinoma

Squamous-cell carcinoma (SCC) is the second most common tumor in horses, and 40%-50% may occur in ocular and adnexal structures. Cyclooxygenase (COX)-2 is an inducible enzyme responsible for the production of prostaglandins that control cell growth and the development and progression of cancer. Mechanisms responsible for the initial upregulation of COX-2 in neoplasia are unclear; prolonged sunlight exposure and mutations in the p53 gene may be possibilities. Because the etiopathogenesis of ocular SCC in horses may involve ultraviolet sunlight and p53 mutations, the purpose of this study was to characterize the immunoreactivity of COX-2 in these tumors. Cyclooxygenase-2 expression was found in 6 of 22 (27%) paraffin-embedded equine SCCs. Cyclooxygenase-2 immunoreactivity was associated with the mitotic index (P < 0.001). Strategies to inhibit COX-2 by the use of topical or systemic COX-2 inhibitors might prove to be a safe and economical treatment in some horses with SCC.

The sunlight OSL response of a commercially available α-Al2O3:C personnel dosimetry material

Carbon-doped, anion-defective aluminium oxide has become a widely used and effective medium for personnel dosimetry applications using optically stimulated luminescence (OSL) techniques. Though the commercial products currently using this material employ light-tight packaging to prevent light-induced effects on the OSL signal, the material could be employed in environments where package integrity cannot be assured. This paper reports on the results of an experiment performed to quantify the effects of sunlight exposure on alpha-Al2O3:C. Samples of commercially available Luxel material were exposed to carefully recorded levels of sunlight both before and after irradiations to determine the nature and magnitude of both activation and fading phenomena in this material. The results confirm that both fading and activation processes are seen in this material and indicate that the material reaches an equilibrium dose level in response to prolonged sunlight exposure equivalent to a dose of approximately 15 mGy under the experimental test conditions.

Lymphocyte alterations after prolonged sunlight exposure.

It has been suggested that prolonged exposure to sunlight may induce systemic or local immune alterations, which may facilitate the development of skin cancer and, perhaps, non-Hodgkin's lymphona. The effects of prolonged sunlight exposure on peripheral blood cells were studied. Leukocytes and lymphocyte subpopulations of 12 volunteers aged 10-45 were investigated before and after a 3-week summer holiday in seaside resorts in Greece. Lymphocyte phenotypes were estimated using monoclonal antibodies and flow cytometry. There were no significant differences with respect to total numbers of T cells, T-helper/inducer, T-suppressor/cytotoxic, B cells or HLA-Dr+ cells. However, we have found evidence of lymphocyte stimulation, reflected in an increase in cells expressing the interleukin-2 receptor (IL-2R) and, more specifically, an increase in the T cells expressing IL-2R and HLA-Dr antigens. An increase in natural killer cells has also been noticed. These findings suggest that prolonged intense exposure to sunlight may be associated with immunostimulation, rather than immunosuppression.

The Effect of Chlorpromazine on Oculocutaneous Pigmentation in the Guinea Pig

In March, 1964, Greiner and Berry (1) described in detail their observations of 70 patients with abnormal oculocutaneous pigmentation following long-term, high dose chlorpromazine therapy. They first noted this phenomenon in 1958. Several common factors were found in most patients; the majority were Caucasians with very fair skin, and had histories of prolonged sunlight exposure. Most of the patients were females and all of these were amenorrheic. The principal neuropsychiatrie disorders for which the drug was given were schizophrenia and mental deficiency. All patients had received very large, daily doses of chlorpromazine. Other authors have subsequently reported similar findings (2-7). The object of the present work was to attempt to reproduce the oculocutaneous pigmentation in the guinea pig. Once a suitable experimental technic was developed, it was hoped to elucidate the cause of the pigmentary defect and if possible the exact chemical nature of the pigment.