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Kinetic and regeneration studies of photocatalytic magnetic separable beads for chromium (VI) reduction under sunlight

Idris A, Hassan N, Rashid R, Ngomsik AF

J Hazard Mater, 2011 Feb 15;186(1):629-35.
PMID: 21168966 DOI: 10.1016/j.jhazmat.2010.11.101

Physical adsorption and photocatalytic reduction of Cr(VI) in magnetic separable beads were investigated. In order to elucidate the kinetics of photocatalytic process, operating parameters such as catalyst dosage and the initial concentration were examined in detail. It was observed that the reduction rate of Cr(VI) increased with an increase in the catalyst loading, as this translated into an increase in the number of available active sites. Critical scrutiny of the percentage of the initial reduction rate versus time at various initial concentration of Cr(VI) revealed that the rate of substrate conversion decreased as the initial concentration increased. The kinetic analysis of the photoreduction showed that the removal of Cr(VI) satisfactory obeyed the pseudo first-order kinetic according to the Langmuir-Hinshelwood (L-H) model and the absorption of Cr(VI) on the magnetic beads surfaces was the controlling step in the entire reduction process. Furthermore, desorption experiments by elution of the loaded gels with sodium hydroxide indicated that the magnetic photocatalyst beads could be reused without significant losses of their initial properties even after 3 adsorption-desorption cycles.

Matched MeSH terms: Sunlight*
Fulltext Knowledge, Attitude and Practice Related to Vitamin D and Its Relationship with Vitamin D Status among Malay Female Office Workers

Jamil NA, Shahudin NN, Abdul Aziz NS, Jia Qi C, Wan Aminuddin WAA, Mat Ludin AF, et al.

Int J Environ Res Public Health, 2019 11 27;16(23).
PMID: 31783521 DOI: 10.3390/ijerph16234735

This study assessed knowledge, attitude and practice (KAP) related to vitamin D and its relationship with vitamin D status among Malay female office workers. A total of 147 women aged between 20 and 55 years were recruited from a university in Kuala Lumpur. They answered questionnaires related to KAP on vitamin D, sun exposure, dietary vitamin D intake and physical activity. Serum 25-hydroxyvitamin D (25OHD) was analysed using an enzyme-linked immunoassay. Nearly half (45%) of the subjects had good knowledge but moderate attitude (76%) and practice (84%) towards sunlight exposure and dietary vitamin D intake. Median serum 25OHD was 34.1 nmol/L with the majority (91%) had vitamin D insufficiency (25OHD < 50 nmol/L). Knowledge was weakly associated with attitude (r = 0.29, p < 0.001) but no association was found between knowledge and practice (r = 0.08, p = 0.355) nor attitude and practice (r = -0.001, p = 0.994). Serum 25OHD was positively associated with sunlight exposure (r = 0.22, p = 0.008) and dietary vitamin D intake (r = 0.37, p < 0.001). It can be implied that this group is at increased risk of low bone health status, which highlights the needs of public health campaigns to improve their vitamin D status.

Matched MeSH terms: Sunlight
Fulltext Laboratory bioefficacy of nine commercial formulations of temephos against larvae of Aedes aegypti (L.), Aedes albopictus Skuse and Culex quinquefasciatus Say

Chen CD, Lee HL, Chan CK, Ang CL, Azahari AH, Lau KW, et al.

Trop Biomed, 2009 Dec;26(3):360-5.
PMID: 20237452

The bioefficacy of nine commercial formulations of temephos against Aedes aegypti, Aedes albopictus and Culex quinquefasciatus larvae were evaluated in the laboratory. WHO larval bioassay with operational dosage of temephos at 1 mg/L was performed. The larval mortality was recorded every 5 minutes until complete mortality was achieved. All formulations of temephos exhibited various toxicity level against Ae. aegypti, Ae. albopictus and Cx. quinquefasciatus. Generally, larvae of Cx. quinquefasciatus was susceptible to all formulations of temephos, followed by Ae. aegypti and Ae. albopictus.

Matched MeSH terms: Sunlight
Fulltext Low Prevalence of Vitamin D Insufficiency among Nepalese Infants Despite High Prevalence of Vitamin D Insufficiency among Their Mothers

Haugen J, Ulak M, Chandyo RK, Henjum S, Thorne-Lyman AL, Ueland PM, et al.

Nutrients, 2016 Dec 21;8(12).
PMID: 28009810 DOI: 10.3390/nu8120825

BACKGROUND: Describing vitamin D status and its predictors in various populations is important in order to target public health measures.
OBJECTIVES: To describe the status and predictors of vitamin D status in healthy Nepalese mothers and infants.
METHODS: 500 randomly selected Nepalese mother and infant pairs were included in a cross-sectional study. Plasma 25(OH)D concentrations were measured by LC-MS/MS and multiple linear regression analyses were used to identify predictors of vitamin D status.
RESULTS: Among the infants, the prevalence of vitamin D insufficiency (25(OH)D <50 nmol/L) and deficiency (<30 nmol/L) were 3.6% and 0.6%, respectively, in contrast to 59.8% and 14.0% among their mothers. Infant 25(OH)D concentrations were negatively associated with infant age and positively associated with maternal vitamin D status and body mass index (BMI), explaining 22% of the variability in 25(OH)D concentration. Global solar radiation, maternal age and BMI predicted maternal 25(OH)D concentration, explaining 9.7% of its variability.
CONCLUSION: Age and maternal vitamin D status are the main predictors of vitamin D status in infants in Bhaktapur, Nepal, who have adequate vitamin D status despite poor vitamin D status in their mothers.

Matched MeSH terms: Sunlight
M/g-C3N4 (M=Ag, Au, and Pd) composite: synthesis via sunlight photodeposition and application towards the degradation of bisphenol A

Hak CH, Sim LC, Leong KH, Lim PF, Chin YH, Saravanan P

Environ Sci Pollut Res Int, 2018 Sep;25(25):25401-25412.
PMID: 29951757 DOI: 10.1007/s11356-018-2632-8

In this work, natural sunlight successfully induced the deposition of gold (Au), silver (Ag), and palladium (Pd) nanoparticles (NPs) with 17.10, 9.07, and 12.70 wt% onto the surface of graphitic carbon nitride (g-C3N4). The photocatalytic evaluation was carried out by adopting Bisphenol A (BPA) as a pollutant under natural sunlight irradiation. The presence of noble metals was confirmed by EDX, HRTEM, and XPS analysis. The deposition of Ag NPs (7.9 nm) resulted in the degradation rate which was 2.15-fold higher than pure g-C3N4 due to its relatively small particle size, contributing to superior charge separation efficiency. Au/g-C3N4 unveiled inferior photoactivity because the LSPR phenomenon provided two pathways for electron transfer between Au NPs and g-C3N4 further diminished the performance. The improved degradation lies crucially on the particle size and Schottky barrier formation at the interface of M/g-C3N4 (M=Au, Ag, and Pd) but not the visible light harvesting properties. The mechanism insight revealed the holes (h+) and superoxide radical (•O2-) radical actively involved in photocatalytic reaction for all composites.

Matched MeSH terms: Sunlight*
Fulltext Maintenance vitamin D3 dosage requirements in Chinese women with post menopausal osteoporosis living in the tropics

Venugopal Y, Hatta SFWM, Musa N, Rahman SA, Ratnasingam J, Paramasivam SS, et al.

Asia Pac J Clin Nutr, 2017 May;26(3):412-420.
PMID: 28429905 DOI: 10.6133/apjcn.042016.10

BACKGROUND AND OBJECTIVES: Vitamin D3 (cholecalciferol) dose required to maintain sufficiency in non- Caucasian women with postmenopausal osteoporosis (PMO) inthe tropics has not been well studied. Some guidelines mandate 800-1000 IU vitamin D/day but the Endocrine Society (US) advocates 1500-2000 IU/day to maintain 25-hydroxyvitamin-D (25(OH)D) concentration at >75 nmol/L. We aimed to establish oral cholecalciferol dose required to maintain 25(OH)D concentration at >75 nmol/L in PMO Chinese Malaysian women, postulating lower dose requirements amongst light-skinned subjects in the tropics.

METHODS AND STUDY DESIGN: 90 Chinese Malaysian PMO women in Kuala Lumpur, Malaysia (2°30'N) with baseline serum 25(OH)D levels >=50 nmol/L were recruited. Prior vitamin D supplements were discontinued and subjects randomized to oral cholecalciferol 25,000 IU/4-weekly (Group-A) or 50,000 IU/4-weekly (Group- B) for 16 weeks, administered under direct observation. Serum 25(OH)D, PTH, serum/urinary calcium were measured at baseline, 8 and 16 weeks.

RESULTS: Baseline characteristics, including osteoporosis severity, sun exposure (~3 hours/week), and serum 25(OH)D did not differ between treatment arms. After 16 weeks, 91% of women sufficient at baseline, remained sufficient on 25,000 IU/4-weekly compared with 97% on 50,000 IU/4-weekly with mean serum 25(OH)D 108.1±20.4 and 114.7±18.4 SD nmol/L respectively (p=0.273). At trial's end, 39% and 80% of insufficient women at baseline attained sufficiency in Group A and Group B (p=0.057). Neither dose was associated with hyperparathyroidism or toxicity.

CONCLUSIONS: Despite pretrial vitamin D supplementation and adequate sun exposure, 25.6% Chinese Malaysian PMO women were vitamin D insufficient indicating sunshine alone cannot ensure sufficiency in the tropics. Both ~900 IU/day and ~1800 IU/day cholecalciferol can safely maintain vitamin D sufficiency in >90% of Chinese Malaysian PMO women. Higher doses are required with baseline concentration <75 nmol/L.

Matched MeSH terms: Sunlight
Medically important solar ultraviolet A. Radiation measurements

Ilyas M, Abdul Aziz D, Tajuddin MR

Int J Dermatol, 1988 Jun;27(5):315-8.
PMID: 3391727

Results from a 6-year study of solar ultraviolet A (UVA) radiation measurements at the equatorial location of Penang (5 degrees N) are presented. On clear days, the diurnal flux reaches a very high dosage of about 3.0 x 10(-2) KWHM-2 around midday. The average daily total flux is in the range of 1.6 x 10(-1) KWHM-2 and does not change much seasonally. The high 83% cloud cover only reduces the incoming flux to about half. The radiation flux represents a lower limit of the incident UVA radiation applicable to much of the equatorial/tropical region.

Matched MeSH terms: Sunlight*
Fulltext Metagenomic sequencing of prokaryotic microbiota from tropical surface seawater

Chan XY, Arumugam R, Choo SW, Yin WF, Chan KG

Genome Announc, 2013;1(4).
PMID: 23950114 DOI: 10.1128/genomeA.00540-13

Tropical seawater harbors a rich diversity of microorganisms as a result of its nutrient-rich environment, constant supply of sufficient sunlight, and warm climate. In this report, we present the complexity of the microbial diversity of the surface seawater of the Georgetown coast as determined using next-generation sequencing technology.

Matched MeSH terms: Sunlight
Milk vitamin D in relation to the 'adequate intake' for 0-6-month-old infants: a study in lactating women with different cultural backgrounds, living at different latitudes

Stoutjesdijk E, Schaafsma A, Nhien NV, Khor GL, Kema IP, Hollis BW, et al.

Br J Nutr, 2017 Nov;118(10):804-812.
PMID: 29103383 DOI: 10.1017/S000711451700277X

Breast-fed infants are susceptible to vitamin D deficiency rickets. The current vitamin D 'adequate intake' (AI) for 0-6-month-old infants is 10 µg/d, corresponding with a human milk antirachitic activity (ARA) of 513 IU/l. We were particularly interested to see whether milk ARA of mothers with lifetime abundant sunlight exposure reaches the AI. We measured milk ARA of lactating mothers with different cultural backgrounds, living at different latitudes. Mature milk was derived from 181 lactating women in the Netherlands, Curaçao, Vietnam, Malaysia and Tanzania. Milk ARA and plasma 25-hydroxyvitamin D (25(OH)D) were analysed by liquid-chromatography-MS/MS; milk fatty acids were analysed by GC-flame ionisation detector (FID). None of the mothers reached the milk vitamin D AI. Milk ARA (n; median; range) were as follows: Netherlands (n 9; 46 IU/l; 3-51), Curaçao (n 10; 31 IU/l; 5-113), Vietnam: Halong Bay (n 20; 58 IU/l; 23-110), Phu Tho (n 22; 28 IU/l; 1-62), Tien Giang (n 20; 63 IU/l; 26-247), Ho-Chi-Minh-City (n 18; 49 IU/l; 24-116), Hanoi (n 21; 37 IU/l; 11-118), Malaysia-Kuala Lumpur (n 20; 14 IU/l; 1-46) and Tanzania-Ukerewe (n 21; 77 IU/l; 12-232) and Maasai (n 20; 88 IU/l; 43-189). We collected blood samples of these lactating women in Curaçao, Vietnam and from Tanzania-Ukerewe, and found that 33·3 % had plasma 25(OH)D levels between 80 and 249·9 nmol/l, 47·3 % between 50 and 79·9 nmol/l and 19·4 % between 25 and 49·9 nmol/l. Milk ARA correlated positively with maternal plasma 25(OH)D (range 27-132 nmol/l, r 0·40) and milk EPA+DHA (0·1-3·1 g%, r 0·20), and negatively with latitude (2°S-53°N, r -0·21). Milk ARA of mothers with lifetime abundant sunlight exposure is not even close to the vitamin D AI for 0-6-month-old infants. Our data may point at the importance of adequate fetal vitamin D stores.

Matched MeSH terms: Sunlight*
Fulltext Mobile robot climber model for experiments application

Syahrul Affandi Saidi, Beh, Jun Long, Mohd Sharizan Md Sarip, Wan Azani Mustafa

Journal of Advanced Research in Applied Sciences and Engineering Technology, 2018;13(1):1-7.
MyJurnal

This article presents a Wall Climbing Robot (WCR) that able to move on ferromagnetic vertical surface to carry out visual inspection process. Visual inspection process is important in the industry to check the condition of storage tank, surface of building, piping or equipment thus can prevents structures collapsing or explosion which would bring a huge loss to the company. Moreover, most of the structures nowadays is expose under the sun and rain, corrosion and cracks could easily occur on the surface after exposing under sunlight and rain a long period of time. Therefore the periodic visual inspection process need to be carry out to detect the damaged occur on the surface of the structure and take action at the fastest time to ensure the safety of the structures and extend the lifespan of the structures. With the well maintenance to the structures, the condition of the structures is monitored and the lifespan is longer. The risk of collapse of the building is decrease by a large margin. Normally, the periodic visual inspection process is performed by operator. Sometime the temporary scaffolding is needed to reach the higher place to carry out the inspection. However, this method create a hazardous environment to the operator and cause the safety of the operator threatened. Therefore, the proposed WCR could help operator to work at the hazardous environment. The permanent magnet is used to provide adhesion for WCR, thus WCR able to move on vertical ferromagnetic surface. The WCR is controlled by operator via wireless remote to reach the higher place or the hazardous environment. The operator then can stream the on the real time images via web browser which connected to the same network with the WCR. Hence, the condition of the surface can be observed.

Matched MeSH terms: Sunlight
Modified PVA-alginate encapsulated photocatalyst ferro photo gels for Cr(VI) reduction

Idris A, Misran E, Hassan N, Abd Jalil A, Seng CE

J Hazard Mater, 2012 Aug 15;227-228:309-16.
PMID: 22682796 DOI: 10.1016/j.jhazmat.2012.05.065

In this study magnetic separable photocatalyst beads containing maghemite nanoparticles (γ-Fe(2)O(3)) in polyvinyl alcohol (PVA) polymer were prepared and used in the reduction of Cr(VI) to Cr(III) in an aqueous solution under sunlight. The unique superparamagnetic property of the photocatalyst contributed by the γ-Fe(2)O(3) and robust property of PVA polymer allow the magnetic beads to be recovered easily and reused for at least 7 times without washing. The concentration of γ-Fe(2)O(3) was varied from 8% (v/v) to 27% (v/v) and the results revealed that the beads with 8% (v/v) γ-Fe(2)O(3) exhibited the best performance where Cr(VI) was reduced to Cr(III) in only 30 min under sunlight. The use of the PVA has improved the bead properties and life cycle of beads which is in line with sustainable practices.

Matched MeSH terms: Sunlight
Fulltext Numerical simulation on the reflection characterisation and performance of a solar collector - a case study of UP M Solar Bowl

Ng, K.M., Adam, N.M., Azmi, B.Z.

Pertanika Journal of Science & Technology, 2012;20(2):283-298.
MyJurnal

A numerical simulation of UPM Solar Bowl is presented in this paper. The numerical analysis considereda general model of solar bowl, which was divided into three modules: (a) reflection characterisation ofthe bowl, (b) solar flux density along the receiver, and (c) radiation contour mapping of the receiver.The governing equations are resolved in a segregated manner using Matlab programming environment.The influence of the tropical clear sky irradiance on the collector was numerically studied, whereas thecollector performance in time domain was also quantified. Single reflection is a major element in thermalconcentration. It was observed that solar flux density of collector substantially deteriorated during offsolar noon hour, in which during 08:00 and 16:00 under clear sky of tropics, the percentage reductionof flux density is over 82% at all points of the receiver. The simulated radiation contour mapping of thereceiver supports the finding. Other results of the UPM Solar Bowl simulation model are also shownand discussed.

Matched MeSH terms: Sunlight
Optimization of degradation of Reactive Black 5 (RB5) and electricity generation in solar photocatalytic fuel cell system

Khalik WF, Ho LN, Ong SA, Voon CH, Wong YS, Yusoff N, et al.

Chemosphere, 2017 Oct;184:112-119.
PMID: 28586651 DOI: 10.1016/j.chemosphere.2017.05.160

The photocatalytic fuel cell (PFC) system was developed in order to study the effect of several operating parameters in degradation of Reactive Black 5 (RB5) and its electricity generation. Light irradiation, initial dye concentration, aeration, pH and cathode electrode are the operating parameters that might give contribution in the efficiency of PFC system. The degradation of RB5 depends on the presence of light irradiation and solar light gives better performance to degrade the azo dye. The azo dye with low initial concentration decolorizes faster compared to higher initial concentration and presence of aeration in PFC system would enhance its performance. Reactive Black 5 rapidly decreased at higher pH due to the higher amount of OH generated at higher pH and Pt-loaded carbon (Pt/C) was more suitable to be used as cathode in PFC system compared to Cu foil and Fe foil. The rapid decolorization of RB5 would increase their voltage output and in addition, it would also increase their Voc, Jsc and Pmax. The breakage of azo bond and aromatic rings was confirmed through UV-Vis spectrum and COD analysis.

Matched MeSH terms: Sunlight
Fulltext Outcome of Various Pterygium Excision Techniques in Tertiary Ophthalmic Centre in East Coast Malaysia

Khairidzan, M.K., Fatimah, S.S., Thangasamy, V.K.

International Medical Journal Malaysia, 2006;5(1):1-2.
MyJurnal

Pterygium is a common external eye problem. It is more frequently seen in tropical areas regions where exposure to ultraviolet sunlight is high. Clinically, a pterygium is a wing shaped fibrovascular growth arising from the bulbar conjunctiva onto the superficial cornea. Complications of pterygium include decreased in visual acuity, dryness, foreign body sensation and persistent redness. Surgical management is the mainstay of treatment for this condition. Numerous surgical techniques have been described in the treatment of pterygium. They include the bare sclera technique, simple direct conjunctival closure, rotational conjunctival graft and conjunctival autograft. Additional treatment to some of these techniques may include the use of beta particle therapy and antimetabolite therapy. Despite the wide range of surgical procedures described for its treatment, the main concern from these procedures has been the recurrence, which could be as high as 30% to 70%. Recurrent pterygium is often accompanied by increased conjunctival inflammation and accelerated corneal involvement. Repeated surgical procedures often only worsen the situation, as loss of conjunctival tissue and scarring can result in obliteration of the fornices and mechanical restriction of extraocular movements, with clinically significant diplopia. In Hospital Tengku Ampuan Afzan, pterygium excision is the most common surgical procedure after cataract extraction. We reviewed patients who had undergone pterygium surgery in HTAA in order to determine the most effective surgical method that could minimize recurrence. PURPOSE: To compare success rates of various excision techniques performed for primary and recurrent pterygium in Hospital Tengku Ampuan Afzan, Kuantan, Pahang.
METHODS: The outcome of 47 cases of pterygia (44 primary and 3 recurrent) excised with various techniques between January 2004 to September 2004 was retrospectively reviewed. Six clinical specialists and four trainees performed the surgical procedures. Outcome was evaluated in terms of recurrence of pterygia onto the cornea. RESULTS: The mean follow up was 3.04 months (range, 1-7 months). All pterygia were morphologically graded as intermediate or fleshy type except one. Four types of pterygium excision techniques were performed. Twenty-four cases had bare sclera, seventeen cases had conjunctival autograft transplantation, six cases had direct conjunctival closure and one had amniotic membrane transplantation done. Recurrence of pterygia occurred in thirteen eyes. Twelve cases from primary pterygia group and one case from recurrent group recurred. Recurrence rate was noted to be higher in direct conjunctival closure (4 out of 6 cases) and lowest in conjunctival autograft transplantation (2 out of 17 cases). Recurrence rate for bare sclera technique was noted to rank second in this study (6 out of 24 cases). In five cases of recurrence, subconjunctival tissue invasions were more than 1 mm but further surgical interventions were not needed at the time of this review was done. CONCLUSIONS: Conjunctival autografting was found to have less recurrent rate when compared with other techniques. The bare sclera technique was quoted to be associated with higher recurrence rate in other literatures. Interestingly in our series, recurrence rate for direct conjunctival closure technique was higher when compared to the former technique. This may be related to inadequate excision of pterygia tissue, which led to direct apposition of abnormal tissue to the cornea in the direct conjunctival closure technique. Even though the bare sclera technique is associated with a higher recurrence rate, it is still the preferred excision technique. This could be because it is less time consuming and technically easier to perform. Based on this study, conjunctival autografting should be the surgical procedure of choice for pteryigum in order to minimise the risk of recurrence.

Matched MeSH terms: Sunlight
Fulltext Outdoor Performance Analysis of a Photovoltaic Thermal (PVT) Collector with Jet Impingement and Compound Parabolic Concentrator (CPC)

Jaaz AH, Hasan HA, Sopian K, Kadhum AAH, Gaaz TS, Al-Amiery AA

Materials (Basel), 2017 Aug 01;10(8).
PMID: 28763048 DOI: 10.3390/ma10080888

This paper discusses the effect of jet impingement of water on a photovoltaic thermal (PVT) collector and compound parabolic concentrators (CPC) on electrical efficiency, thermal efficiency and power production of a PVT system. A prototype of a PVT solar water collector installed with a jet impingement and CPC has been designed, fabricated and experimentally investigated. The efficiency of the system can be improved by using jet impingement of water to decrease the temperature of the solar cells. The electrical efficiency and power output are directly correlated with the mass flow rate. The results show that electrical efficiency was improved by 7% when using CPC and jet impingement cooling in a PVT solar collector at 1:00 p.m. (solar irradiance of 1050 W/m² and an ambient temperature of 33.5 °C). It can also be seen that the power output improved by 36% when using jet impingement cooling with CPC, and 20% without CPC in the photovoltaic (PV) module at 1:30 p.m. The short-circuit current ISC of the PV module experienced an improvement of ~28% when using jet impingement cooling with CPC, and 11.7% without CPC. The output of the PV module was enhanced by 31% when using jet impingement cooling with CPC, and 16% without CPC.

Matched MeSH terms: Sunlight
Ozone-climate interactions and effects on solar ultraviolet radiation

Bais AF, Bernhard G, McKenzie RL, Aucamp PJ, Young PJ, Ilyas M, et al.

Photochem Photobiol Sci, 2019 Mar 01;18(3):602-640.
PMID: 30810565 DOI: 10.1039/c8pp90059k

This report assesses the effects of stratospheric ozone depletion and anticipated ozone recovery on the intensity of ultraviolet (UV) radiation at the Earth's surface. Interactions between changes in ozone and changes in climate, as well as their effects on UV radiation, are also considered. These evaluations focus mainly on new knowledge gained from research conducted during the last four years. Furthermore, drivers of changes in UV radiation other than ozone are discussed and their relative importance is assessed. The most important of these factors, namely clouds, aerosols and surface reflectivity, are related to changes in climate, and some of their effects on short- and long-term variations of UV radiation have already been identified from measurements. Finally, projected future developments in stratospheric ozone, climate, and other factors affecting UV radiation have been used to estimate changes in solar UV radiation from the present to the end of the 21st century. New instruments and methods have been assessed with respect to their ability to provide useful and accurate information for monitoring solar UV radiation at the Earth's surface and for determining relevant exposures of humans. Evidence since the last assessment reconfirms that systematic and accurate long-term measurements of UV radiation and stratospheric ozone are essential for assessing the effectiveness of the Montreal Protocol and its Amendments and adjustments. Finally, we have assessed aspects of UV radiation related to biological effects and human health, as well as implications for UV radiation from possible solar radiation management (geoengineering) methods to mitigate climate change.

Matched MeSH terms: Sunlight
Fulltext Perceptions and opinions towards skin cancer prevention in Malaysia: a qualitative approach

Al-Naggar RA, Al-Naggar TH, Bobryshev YV

Asian Pac J Cancer Prev, 2011;12(4):995-9.
PMID: 21790240

INTRODUCTION: Malignant melanoma in particular is one of the few remaining cancers with an increasing incidence.

OBJECTIVES: The objective of this study is to explore the perceptions and opinions of young Malaysians towards skin cancer prevention.

METHODOLOGY: Focus group discussions were conducted among 33 medical science students from Management and Science University (MSU), Shah Alam, Malaysia, using convenience sampling. Students were divided into 4 focus groups consisting of 8, 8, 9 and 8 students respectively. The facilitator wrote down the conversations and data obtained were classified into various categories and analyzed manually.

RESULTS: The majority of the participants mentioned that overexposure to ultraviolet light is the commonest cause of skin cancer but also that the most benefit we get from sun ight is vitamin D synthesis. The majority mentioned that the best prevention measure for skin cancer is using a sunscreen, followed by limit exposure to the sun.

CONCLUSION: The present study demonstrated there is a lack of knowledge regarding screening methods and prevention measures of skin cancer. Therefore, there is a need to establish health education unit in all universities to educate all university students regarding various health problems including skin cancer prevention.

Matched MeSH terms: Sunlight/adverse effects
Perspectives in dermatology: Malaysia

Petit JH

Int J Dermatol, 1976 Sep;15(7):505-12.
PMID: 965135
Matched MeSH terms: Sunlight
Fulltext Pharmacologically antagonizing the CXCR4-CXCL12 chemokine pathway with AMD3100 inhibits sunlight-induced skin cancer

Sarchio SNE, Scolyer RA, Beaugie C, McDonald D, Marsh-Wakefield F, Halliday GM, et al.

J Invest Dermatol, 2014 Apr;134(4):1091-1100.
PMID: 24226205 DOI: 10.1038/jid.2013.424

One way sunlight causes skin cancer is by suppressing anti-tumor immunity. A major mechanism involves altering mast cell migration via the C-X-C motif chemokine receptor 4-C-X-C motif chemokine ligand 12 (CXCR4-CXCL12) chemokine pathway. We have discovered that pharmacologically blocking this pathway with the CXCR4 antagonist AMD3100 prevents both UV radiation-induced immune suppression and skin cancer. The majority of control mice receiving UV-only developed histopathologically confirmed squamous cell carcinomas. In contrast, skin tumor incidence and burden was significantly lower in AMD3100-treated mice. Perhaps most striking was that AMD3100 completely prevented the outgrowth of latent tumors that occurred once UV irradiation ceased. AMD3100 protection from UV immunosuppression and skin cancer was associated with reduced mast cell infiltration into the skin, draining lymph nodes, and the tumor itself. Thus a major target of CXCR4 antagonism was the mast cell. Our results indicate that interfering with UV-induced CXCL12 by antagonizing CXCR4 significantly inhibits skin tumor development by blocking UV-induced effects on mast cells. Hence, the CXCR4-CXCL12 chemokine pathway is a novel therapeutic target in the prevention of UV-induced skin cancer.

Matched MeSH terms: Sunlight*
Fulltext Photochemical Synthesis of Nanosheet Tin Di/Sulfide with Sunlight Response on Water Pollutant Degradation

Matmin J, Jalani MA, Osman H, Omar Q, Ab'lah N, Elong K, et al.

Nanomaterials (Basel), 2019 Feb 14;9(2).
PMID: 30769911 DOI: 10.3390/nano9020264

The photochemical synthesis of two-dimensional (2D) nanostructured from semiconductor materials is unique and challenging. We report, for the first time, the photochemical synthesis of 2D tin di/sulfide (PS-SnS₂-x, x = 0 or 1) from thioacetamide (TAA) and tin (IV) chloride in an aqueous system. The synthesized PS-SnS₂-x were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), a particle size distribution analyzer, X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), thermal analysis, UV⁻Vis diffuse reflectance spectroscopy (DR UV⁻Vis), and photoluminescence (PL) spectroscopy. In this study, the PS-SnS₂-x showed hexagonally closed-packed crystals having nanosheets morphology with the average size of 870 nm. Furthermore, the nanosheets PS-SnS₂-x demonstrated reusable photo-degradation of methylene blue (MB) dye as a water pollutant, owing to the stable electronic conducting properties with estimated bandgap (Eg) at ~2.5 eV. Importantly, the study provides a green protocol by using photochemical synthesis to produce 2D nanosheets of semiconductor materials showing photo-degradation activity under sunlight response.

Matched MeSH terms: Sunlight

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