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Feedforward backpropagation, Genetic Algorithm approaches for predicting reference evapotranspiration

Shafika Sultan Abdullah, M.A. Malek, Namiq Sultan Abdullah, A. Mustapha

Sains Malaysiana, 2015;44:1053-1059.

Water scarcity is a global concern, as the demand for water is increasing tremendously and poor management of water resources will accelerates dramatically the depletion of available water. The precise prediction of evapotranspiration (ET), that consumes almost 100% of the supplied irrigation water, is one of the goals that should be adopted in order to avoid more squandering of water especially in arid and semiarid regions. The capabilities of feedforward backpropagation neural networks (FFBP) in predicting reference evapotranspiration (ET0) are evaluated in this paper in comparison with the empirical FAO Penman-Monteith (P-M) equation, later a model of FFBP+Genetic Algorithm (GA) is implemented for the same evaluation purpose. The study location is the main station in Iraq, namely Baghdad Station. Records of weather variables from the related meteorological station, including monthly mean records of maximum air temperature (Tmax), minimum air temperature (Tmin), sunshine hours (Rn), relative humidity (Rh) and wind speed (U2), from the related meteorological station are used in the prediction of ET0 values. The performance of both simulation models were evaluated using statistical coefficients such as the root of mean squared error (RMSE), mean absolute error (MAE) and coefficient of determination (R2). The results of both models are promising, however the hybrid model shows higher efficiency in predicting ET0 and could be recommended for modeling of ET0 in arid and semiarid regions.

Matched MeSH terms: Sunlight
Fulltext Controllable Electrochemical Synthesis of Reduced Graphene Oxide Thin-Film Constructed as Efficient Photoanode in Dye-Sensitized Solar Cells

Chong SW, Lai CW, Abd Hamid SB

Materials (Basel), 2016 Jan 25;9(2).
PMID: 28787869 DOI: 10.3390/ma9020069

A controllable electrochemical synthesis to convert reduced graphene oxide (rGO) from graphite flakes was introduced and investigated in detail. Electrochemical reduction was used to prepare rGO because of its cost effectiveness, environmental friendliness, and ability to produce rGO thin films in industrial scale. This study aimed to determine the optimum applied potential for the electrochemical reduction. An applied voltage of 15 V successfully formed a uniformly coated rGO thin film, which significantly promoted effective electron transfer within dye-sensitized solar cells (DSSCs). Thus, DSSC performance improved. However, rGO thin films formed in voltages below or exceeding 15 V resulted in poor DSSC performance. This behavior was due to poor electron transfer within the rGO thin films caused by poor uniformity. These results revealed that DSSC constructed using 15 V rGO thin film exhibited high efficiency (η = 1.5211%) attributed to its higher surface uniformity than other samples. The addition of natural lemon juice (pH ~ 2.3) to the electrolyte accelerated the deposition and strengthened the adhesion of rGO thin film onto fluorine-doped tin oxide (FTO) glasses.

Matched MeSH terms: Sunlight
Photoprotection awareness and practices among patients with systemic lupus erythematosus and its association with disease activity and severity

Abdul Kadir WD, Jamil A, Shaharir SS, Md Nor N, Abdul Gafor AH

Lupus, 2018 Jul;27(8):1287-1295.
PMID: 29665756 DOI: 10.1177/0961203318770016

Objective The objective of this paper is to determine photoprotection awareness, knowledge, practices, and its relationship with disease activity and damage in patients with systemic lupus erythematosus (SLE).
Methods A cross-sectional study was performed. Data were acquired from in-person interviews and medical records.
Results A total of 199 (89.6%) females and 23 (10.4%) males were recruited. Median age was 39.00 (interquartile range (IQR) 18) years, disease duration 12.12 (IQR 8) years, Fitzpatrick skin phototype III 119 (53.6%) and IV 81 (36.5%). Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2 K) was 2.95 (IQR 4) while Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SLICC-ACR DI) was 1.20 (IQR 2). The majority 205 (92.3%) were aware of sun exposure effects on SLE. Photoprotection methods were shade seeking 209 (94.1%), sun avoidance 212 (95.5%), long pants 168 (75.7%), long sleeves 155 (69.8%), sunscreen 116 (52.3%), sunglasses 114 (51.4%) and head cover 103 (46.4%). Significantly higher photoprotection practice scores (PPS) were observed in females, Malays, and individuals with higher education level and internet accessibility. PPS were not significantly correlated with SLICC-ACR DI and SLEDAI-2 K. Independent predictors for good photoprotection practice (GPP) were ethnicity (OR = 3.66, 95% CI 1.78-7.53), awareness (OR = 3.77, 95% CI 1.09-13.08) and cutaneous involvement (OR = 2.43, 95% CI 1.11-5.28). Photoprotection methods and GPP were not predictors for disease activity or damage.
Conclusion Photoprotection awareness and knowledge was good. Shade seeking and sun avoidance were the common photoprotection methods practised. The use of sunscreen requires improvement. Photoprotection awareness and cutaneous manifestation were predictors for GPP. Neither photoprotection methods nor GPP were associated with disease activity or damage.
Study site: Nephrology, Rheumatology and Dermatology clinics, Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM), Kuala Lumpur, Malaysia

Matched MeSH terms: Sunlight/adverse effects
Study of the Behaviors of Gunshot Residues from Spent Cartridges by Headspace Solid-Phase Microextraction-Gas Chromatographic Techniques

Chang KH, Yew CH, Abdullah AF

J Forensic Sci, 2015 Jul;60(4):869-77.
PMID: 25771708 DOI: 10.1111/1556-4029.12745

Gunshot residues, produced after shooting activity, have acquired their importance in analysis due to the notoriety of firearms-related crimes. In this study, solid-phase microextraction was performed to extract the headspace composition of spent cartridges using 85-μm polyacrylate fiber at 66°C for 21 min. Organic compounds, that is, naphthalene, 2,6-dinitrotoluene, 2,4-dinitrotoluene, diphenylamine, and dibutyl phthalate were detected and analyzed by gas chromatography-flame ionization detection technique. Evaluation of chromatograms for diphenylamine, dibutyl phthalate, and naphthalene indicates the period after a gunshot was discharged, whether it was 1 days, 2-4 days, <5 days, 10 days, 20 days, or more than 30 days ago. This study revealed the potential effects of environmental factors such as occasional wind blow and direct sunlight on the estimation of time after spent cartridges were discharged. In conclusion, we proposed reliable alternative in analyzing the headspace composition of spent cartridges in a simulated crime scene.

Matched MeSH terms: Sunlight
Fulltext Enhancing Photocurrent Performance Based on Photoanode Thickness and Surface Plasmon Resonance Using Ag-TiO2 Nanocomposites in Dye-Sensitized Solar Cells

Lokman MQ, Shafie S, Shaban S, Ahmad F, Jaafar H, Mohd Rosnan R, et al.

Materials (Basel), 2019 Jun 30;12(13).
PMID: 31262020 DOI: 10.3390/ma12132111

This study investigated the different thicknesses of TiO2 photoanode films and the effect of surface plasmon resonance (SPR) of Ag-TiO2 nanocomposites on the current-voltage (I-V) performance of dye-sensitized solar cells (DSSC). The TiO2 layer was deposited using the doctor blade technique and the thickness of the TiO2 films was controlled by using a different number of Scotch tape layers. The silver nanoparticles (AgNP) were synthesised using a chemical reduction method and the concentration of sodium citrate as a reducing agent was varied from 4 to 12 mM to study the effect of citrate ion on the size of the nanoparticles. Ag-TiO2 nanopowder was prepared by adding pure anatase TiO2 powder into AgNP colloidal solution. The mixture was left to dry for 24 h to obtain Ag-TiO2 powder for paste preparation. The three-layer Scotch tape, with thickness of 14.38 µm, achieved a high efficiency of 4.14%. This results showed that three layers was the optimal thickness to improve dye loading and to reduce the charge recombination rate. As for the Ag-TiO2 nanocomposites, 10 mM of AgNP, with a mean diameter of 65.23 nm and high efficiency of 6.92%, proved that SPR can enhance the absorption capability of dye and improve the photon-to-electron generation.

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
Fulltext Development of a Novel Design and Subsequent Fabrication of an Automated Touchless Hand Sanitizer Dispenser to Reduce the Spread of Contagious Diseases

Das A, Barua A, Mohimin MA, Abedin J, Khandaker MU, Al-Mugren KS

Healthcare (Basel), 2021 Apr 10;9(4).
PMID: 33920290 DOI: 10.3390/healthcare9040445

BACKGROUND: The use of a touchless automated hand sanitizer dispenser may play a key role to reduce contagious diseases. The key problem of the conventional ultrasonic and infra-red-based dispensers is their malfunctioning due to the interference of sunlight, vehicle sound, etc. when deployed in busy public places. To overcome such limitations, this study introduced a laser-based sensing device to dispense sanitizer in an automated touchless process.
METHOD: The dispensing system is based on an Arduino circuit breadboard where an ATmega328p microcontroller was pre-installed. To sense the proximity, a light-dependent resistor (LDR) is used where the laser light is to be blocked after the placement of human hands, hence produced a sharp decrease in the LDR sensor value. Once the LDR sensor value exceeds the lower threshold, the pump is actuated by the microcontroller, and the sanitizer dispenses through the nozzle.
RESULTS AND DISCUSSION: A novel design and subsequent fabrication of a low-cost, touchless, automated sanitizer dispenser to be used in public places, was demonstrated. The overall performance of the manufactured device was analyzed based on the cost and power consumption, and environmental factors by deploying it in busy public places as well as in indoor environment in major cities in Bangladesh, and found to be more efficient and cost-effective compared to other dispensers available in the market. A comprehensive discussion on this unique design compared to the conventional ultrasonic and infra-red based dispensers, is presented to show its suitability over the commercial ones. The guidelines of the World Health Organization are followed for the preparation of sanitizer liquid. A clear demonstration of the circuitry connections is presented herein, which facilitates the interested individual to manufacture a cost-effective dispenser device in a relatively short time and use it accordingly. Conclusion: This study reveals that the LDR-based automated hand sanitizer dispenser system is a novel concept, and it is cost-effective compared to the conventional ones. The presented device is expected to play a key role in contactless hand disinfection in public places, and reduce the spread of infectious diseases in society.

Matched MeSH terms: Sunlight
Role of nanocatalyst in the treatment of organochlorine compounds - A review

El-Sheikh MA, Hadibarata T, Yuniarto A, Sathishkumar P, Abdel-Salam EM, Alatar AA

Chemosphere, 2020 Nov 04.
PMID: 33220978 DOI: 10.1016/j.chemosphere.2020.128873

Since a few centuries ago, organochlorine compounds (OCs) become one of the threatened contaminants in the world. Due to the lipophilic and hydrophobic properties, OCs always discover in fat or lipid layers through bioaccumulation and biomagnification. The OCs are able to retain in soil, sediment and water for long time as it is volatile, OCs will evaporate from soil and condense in water easily and frequently, which pollute the shelter of aquatic life and it affects the function of organs and damage system in human body. Photocatalysis that employs the usage of semiconductor nanophotocatalyst and solar energy can be the possible alternative for current conventional water remediation technologies. With the benefits of utilizing renewable energy, no production of harmful by-products and easy operation, degradation of organic pollutants in rural water bodies can be established. Besides, nanophotocatalyst that is synthesized with nanotechnology outnumbered conventional catalyst with larger surface area to volume ratio, thus higher photocatalytic activity is observed. In contrast, disadvantages particularly no residual effect in water distribution network, requirement of post-treatment and easily affected by various factors accompanied with photocatalysis method cannot be ignored. These various factors constrained the photocatalytic efficiency via nanocatalysts which causes the full capacity of solar photocatalysis has yet to be put into practice. Therefore, further modifications and research are still required in nanophotocatalysts' synthesis to overcome limitations such as large band gaps and photodecontamination.

Matched MeSH terms: Sunlight
Fulltext Solar tree

Madya Mastika binti Ahmad, Amirah binti Mohd Arif

Journal of Engineering and Science Research, 2018;2(4):34-38.
MyJurnal

In this day and age, with the ever-growing population and energy demand, we should take the renewable option route in our energy source. We should also keep in mind that said energy should not cause any lasting environmental damage, one of the perfect example being solar energy. A country that is hot and sunny all year long is the perfect contributor to solar energy, case in point, Malaysia. With that in mind Solar Tree is designed and developed to facilitate consumers who need electric power at any place, anytime, anywhere. The objective of this study is to assess a mini project in the likes of Solar Tree that can generate electricity without harming the environment, despite the weather. Intended specifically to be a mini project, it is understandable that electricity generated is limited, with only up to 500W in total. As a trial, two electronic devices were tested, specifically a mobile phone and a laptop, as both devices are used almost every day. The data collected is then tabulated and analysed. It was concluded the solar tree developed proved efficient in charging both devices and will continue to do so given enough sunlight.

Matched MeSH terms: Sunlight
Fulltext Competitive interaction of Axonopus compressus and Asystasia gangetica under contrasting sunlight intensity

Samedani B, Juraimi AS, Anwar MP, Rafii MY, Sheikh Awadz SH, Anuar AR

ScientificWorldJournal, 2013;2013:308646.
PMID: 24163618 DOI: 10.1155/2013/308646

Axonopus compressus is one of the native soft grass species in oil palm in Malaysia which can be used as a cover crop. The competitive ability of A. compressus to overcome A. gangetica was studied using multiple-density, multiple-proportion replacements series under a glasshouse and full sunlight conditions in a poly bag for 10 weeks. A. compressus produced more dry weight and leaf area when competing against A. gangetica than in monoculture at both densities in the full sunlight and at high density in the shade. Moreover, the relative yield and relative crowding coefficients also indicated A. compressus is a stronger competitor than A. gangetica at both densities in the full sunlight and high density in the shade. It seemed that A. gangetica plants in the shade did not compete with each other and were more competitive against A. compressus as could influence A. compressus height in the shade. It is concluded that although suppression of A. gangetica by A. compressus occurred under full sunlight, irrespective of plant density, this ability reduced under shade as A. compressus density decreased. The result suggests that A. compressus in high density could be considered as a candidate for cover crops under oil palm canopy.

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
Fulltext Coral mass spawning predicted by rapid seasonal rise in ocean temperature

Keith SA, Maynard JA, Edwards AJ, Guest JR, Bauman AG, van Hooidonk R, et al.

Proc Biol Sci, 2016 05 11;283(1830).
PMID: 27170709 DOI: 10.1098/rspb.2016.0011

Coral spawning times have been linked to multiple environmental factors; however, to what extent these factors act as generalized cues across multiple species and large spatial scales is unknown. We used a unique dataset of coral spawning from 34 reefs in the Indian and Pacific Oceans to test if month of spawning and peak spawning month in assemblages of Acropora spp. can be predicted by sea surface temperature (SST), photosynthetically available radiation, wind speed, current speed, rainfall or sunset time. Contrary to the classic view that high mean SST initiates coral spawning, we found rapid increases in SST to be the best predictor in both cases (month of spawning: R(2) = 0.73, peak: R(2) = 0.62). Our findings suggest that a rapid increase in SST provides the dominant proximate cue for coral mass spawning over large geographical scales. We hypothesize that coral spawning is ultimately timed to ensure optimal fertilization success.

Matched MeSH terms: Sunlight
Comparative studies of RSM Box-Behnken and ANN-Anfis fuzzy statistical analysis for seawater biodegradability using TiO2 photocatalyst

Mohammed N, Palaniandy P, Shaik F, Mewada H, Balakrishnan D

Chemosphere, 2023 Feb;314:137665.
PMID: 36581118 DOI: 10.1016/j.chemosphere.2022.137665

In this approach, a batch reactor was employed to study the degradation of pollutants under natural sunlight using TiO2 as a photocatalyst. The effects of photocatalyst dosage, reaction time and pH were investigated by evaluating the percentage removal efficiencies of total organic carbon (TOC), chemical oxygen demand (COD), biological oxygen demand (BOD) and biodegradability (BOD/COD). Design Expert-Response Surface Methodology Box Behnken Design (BBD) and MATLAB Artificial Neural Network - Adaptive Neuro Fuzzy Inference system (ANN-ANFIS) methods were employed to perform the statistical modelling. The experimental values of maximum percentage removal efficiencies were found to be TOC = 82.4, COD = 85.9, BOD = 30.9% and biodegradability was 0.070. According to RSM-BBD and ANFIS analysis, the maximum percentage removal efficiencies were found to be TOC = 90.3, 82.4; COD = 85.4, 85.9; BOD = 28.9, 30.9% and the biodegradability = 0.074, 0.080 respectively at the pH 7.5, reaction time 300 min and photocatalyst dosage of 4 g L-1. The study reveals both models found to be well predicted as compared with experimental values. The values of R2 for RSM-BBD (0.920) and for ANFIS (0.990) models were almost close to 1. The ANFIS model was found to be marginally better than that of RSM-BBD.

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
Fulltext Hydroxypropylcellulose as a novel green reservoir for the synthesis, stabilization, and storage of silver nanoparticles

Hussain MA, Shah A, Jantan I, Shah MR, Tahir MN, Ahmad R, et al.

Int J Nanomedicine, 2015;10:2079-88.
PMID: 25844038 DOI: 10.2147/IJN.S75874

Polysaccharides are attracting the vigil eye of researchers in order to design the green synthesis of silver nanoparticles (Ag NPs) of diverse size, shape, and application. We report an environmentally friendly method to synthesize Ag NPs where no physical reaction conditions were employed. Hydroxypropylcellulose (HPC) was used as a template nanoreactor, stabilizer, and capping agent to obtain Ag NPs. Different concentrations of AgNO3 solutions (50 mmol, 75 mmol, and 100 mmol) were mixed with a concentrated aqueous solution of HPC and the progress of the reaction was monitored by noting color changes of the reaction mixture at different reaction times for up to 24 hours. Characteristic ultraviolet-visible spectroscopy (UV/Vis) absorption bands of Ag NPs were observed in the range of 388-452 nm. The morphology of the Ag NPs was studied by scanning electron microscopy, transmission electron microscopy (TEM), and atomic force microscopy. The TEM images confirmed that the size of the Ag NPs was in the range of 25-55 nm. Powder X-ray diffraction studies showed that the crystal phase of the Ag NPs was face-centered cubic. The as-prepared Ag NPs were found to be stable, and no changes in size and morphology were observed after storage in HPC thin films over 1 year, as indicated by UV/Vis spectra. So, the present work furnishes a green and economical strategy for the synthesis and storage of stable Ag NPs. As-synthesized Ag NPs showed significant antimicrobial activity against different bacterial (Escherichia coli, Staphylococcus epidermidis, S. aureus, Bacillus subtilis, Pseudomonas aeruginosa) and fungal strains (Actinomycetes and Aspergillus niger).

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*
Heterojunction photocatalysts for artificial nitrogen fixation: fundamentals, latest advances and future perspectives

Lee J, Tan LL, Chai SP

Nanoscale, 2021 Apr 21;13(15):7011-7033.
PMID: 33889914 DOI: 10.1039/d1nr00783a

As an indispensable energy source, ammonia plays an essential role in agriculture and various industries. Given that the current ammonia production is still dominated by the energy-intensive and high carbon footprint Haber-Bosch process, photocatalytic nitrogen fixation represents a low-energy consuming and sustainable approach to generate ammonia. Heterostructured photocatalysts are hybrid materials composed of semiconductor materials containing interfaces that make full use of the unique superiorities of the constituents and synergistic effects between them. These promising photocatalysts have superior performances and substantial potential in photocatalytic reduction of nitrogen. In this review, a wide spectrum of recently developed heterostructured photocatalysts for nitrogen fixation to ammonia are evaluated. The fundamentals of solar-to-ammonia conversion, basic principles of various heterojunction photocatalysts and modification strategies are systematically reviewed. Finally, a brief summary and perspectives on the ongoing challenges and directions for future development of nitrogen photofixation catalysts are also provided.

Matched MeSH terms: Sunlight
Engineering surface oxygen defects on tungsten oxide to boost photocatalytic oxygen evolution from water splitting

Chew YH, Tang JY, Tan LJ, Choi BWJ, Tan LL, Chai SP

Chem Commun (Camb), 2019 May 28;55(44):6265-6268.
PMID: 31086906 DOI: 10.1039/c9cc01449g

The engineering of surface oxygen vacancies (OVs) in WO3 was primitively done using a facile solvothermal method. The photocatalytic activities of the as-prepared samples were studied by evaluating their performances in the photocatalytic OER. The best sample (W-3) yielded 57.6 μmol of O2 in 6 h under the illumination of simulated sunlight.

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
Fulltext Effects of sun exposure on 25(OH) vitamin D concentration in urban and rural women in Malaysia

Nurbazlin M, Chee WS, Rokiah P, Tan AT, Chew YY, Nusaibah AR, et al.

Asia Pac J Clin Nutr, 2013;22(3):391-9.
PMID: 23945409 DOI: 10.6133/apjcn.2013.22.3.15

Ultraviolet B sunlight exposure is a primary source of vitamin D. There have been reports of low vitamin D status amongst the Malaysian population despite it being a tropical country. This study was conducted to determine the influence of sun exposure on 25(OH)D concentrations in urban and rural women in Malaysia and factors predicting 25(OH)D concentrations. Women aged above 45 years were recruited from urban (n=107) and rural areas (n=293). Subjects were interviewed regarding their outdoor activities and usual outdoor attire over the previous week. 25(OH)D concentrations were analyzed using the vitamin D3 (25-OH) electrochemiluminescence immunoassay. Median (Q1-Q3) age of the participants was 57 (53-61) years old. Median (Q1-Q3) 25(OH)D concentration of rural women was significantly higher [69.5 (59.0-79.1) nmol/L] compared to urban women [31.9 (26.1- 45.5) nmol/L] (p<0.001). Rural women spent more time in the sun compared to urban women (7.83 (3.67-14.7) vs 2.92 (1.17-4.92) hours, p<0.001), although the fraction of body surface area (BSA) exposed to sunlight was significantly higher in the urban group [0.21 (0.21-0.43) vs 0.12 (0.07-0.17), p<0.001]. The calculated sun index (hours of sun exposure per week × fraction of BSA) was significantly higher in rural [0.89 (0.42-1.83)] compared to urban women [0.72 (0.26-1.28)], p=0.018. In the stepwise linear regression, rural dwelling increased the serum 25(OH)D by 31.74 nmol/L and 25(OH)D concentrations increased by 1.93 nmol/L for every unit increment in sun index. Urban women in Malaysia had significantly lower vitamin D status compared to rural women. Rural dwelling and sun index were key factors influencing vitamin D status in Malaysian women.

Matched MeSH terms: Sunlight*

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