Displaying publications 1 - 20 of 317 in total

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  1. Karman SB, Diah SZ, Gebeshuber IC
    Sensors (Basel), 2012;12(11):14232-61.
    PMID: 23202158 DOI: 10.3390/s121114232
    Animal senses cover a broad range of signal types and signal bandwidths and have inspired various sensors and bioinstrumentation devices for biological and medical applications. Insects, such as desert ants and honeybees, for example, utilize polarized skylight pattern-based information in their navigation activities. They reliably return to their nests and hives from places many kilometers away. The insect navigation system involves the dorsal rim area in their compound eyes and the corresponding polarization sensitive neurons in the brain. The dorsal rim area is equipped with photoreceptors, which have orthogonally arranged small hair-like structures termed microvilli. These are the specialized sensors for the detection of polarized skylight patterns (e-vector orientation). Various research groups have been working on the development of novel navigation systems inspired by polarized skylight-based navigation in animals. Their major contributions are critically reviewed. One focus of current research activities is on imitating the integration path mechanism in desert ants. The potential for simple, high performance miniaturized bioinstrumentation that can assist people in navigation will be explored.
    Matched MeSH terms: Light*
  2. Mahdi, M.A., Md. Ali, M.I., Ahmad, A., Zamzuri, A.K.
    ASM Science Journal, 2008;2(2):123-127.
    MyJurnal
    In this paper a study on the wideband double-pass Raman fibre amplifier with mirror as the pump reflector is reported. The pump lights at 1435 nm and 1455 nm were launched in a co-directional manner with respect to the input signal. The double-pass direction of the signal was achieved through a fibre loop mirror constructed using an optical circulator. It was shown that multiple signal amplification was achieved without any disturbance of stimulated Brillouin scattering.
    Matched MeSH terms: Light
  3. Zhan SZ, Zhang GH, Li JH, Liu JL, Zhu SH, Lu W, et al.
    J Am Chem Soc, 2020 Apr 01;142(13):5943-5947.
    PMID: 32187495 DOI: 10.1021/jacs.0c00090
    Exohedral cuprofullerenes with 6-, 12-, or 24-nuclearity were obtained by utilizing fluorocarboxylic/dicarboxylic acid under solvothermal conditions. The 24-nuclear molecule presents a C60@Cu24 core-shell structure with a rhombicuboctahedron Cu24 coated on the C60 core, representing the highest nuclearity in metallofullerene. The resultant complexes show an efficient absorption of visible light as opposed to the pristine C60. TD-DFT calculations revealed the charge transfer from Cu(I) and O atoms to the fullerene moiety dominates the photophysical process.
    Matched MeSH terms: Light
  4. Hitam CNC, Jalil AA
    J Environ Manage, 2020 Mar 15;258:110050.
    PMID: 31929077 DOI: 10.1016/j.jenvman.2019.110050
    Photocatalytic degradation is among the promising technology for removal of various dyes and organic contaminants from environment owing to its excellent catalytic activity, low energy utilization, and low cost. As one of potential photocatalysts, Fe2O3 has emerged as an important material for degradation of numerous dyes and organic contaminants caused by its tolerable band gap, wide harvesting of visible light, good stability and recyclability. The present review thoroughly summarized the classification, synthesis route of Fe2O3 with different morphologies, and several modifications of Fe2O3 for improved photocatalytic performance. These include the incorporation with supporting materials, formation of heterojunction with other semiconductor photocatalysts, as well as the fabrication of Z-scheme. Explicitly, the other photocatalytic applications of Fe2O3, including for removal of heavy metals, reduction of CO2, evolution of H2, and N2 fixation are also deliberately discussed to further highlight the huge potential of this catalyst. Moreover, the prospects and future challenges are also comprised to expose the unscrutinized criteria of Fe2O3 photocatalyst. This review aims to contribute a knowledge transfer for providing more information on the potential of Fe2O3 photocatalyst. In the meantime, it might give an idea for utilization of this photocatalyst in other environmental remediation application.
    Matched MeSH terms: Light*
  5. Hossain SS, Tarek M, Munusamy TD, Rezaul Karim KM, Roopan SM, Sarkar SM, et al.
    Environ Res, 2020 09;188:109803.
    PMID: 32590149 DOI: 10.1016/j.envres.2020.109803
    In this work, the photocatalytic property of p-type CuO was tailored by creating a heterojunction with n-type CdS. The CuO/CdS nanocomposite photocatalyst was synthesized by the ultrasound-assisted-wet-impregnation method and the physicochemical and optical properties of the catalysts were evaluated by using N2 physisorption, X-Ray Diffraction (XRD),X-Ray Photoelectron Spectroscopy (XPS), Raman spectroscopy, Transmission electron microscopy (TEM), Energy dispersive X-Ray (EDX) mapping, Field Emission Scanning Electron Microscope (FE-SEM), UV-Vis and photoluminescence spectroscopy experiments. Detailed characterization revealed the formation of a nanocomposite with a remarkable improvement in the charge carrier (electron/hole) separation. The photocatalytic degradation efficiencies of CuO and CuO/CdS were investigated for different dyes, for instance, rhodamine B (RhB), methylene blue (MLB), methyl blue (MB) and methyl orange (MO) under visible light irradiation. The obtained dye degradation efficiencies were ~93%, ~75%, ~83% and ~80%, respectively. The quantum yield for RhB degradation under visible light was 6.5 × 10-5. Reusability tests revealed that the CuO/CdS photocatalyst was recyclable up to four times. The possible mechanisms for the photocatalytic dye degradation over CuO/CdS nanocomposite were elucidated by utilizing various scavengers. Through these studies, it can be confirmed that the conduction band edges of CuO and CdS play a significant role in producing O2-. The produced O2- degraded the dye molecules in the bulk solution whereas the valence band position of CuO acted as the water oxidation site. In conclusion, the incorporation of CuO with CdS was demonstrated to be a viable strategy for the efficient photocatalytic degradation of dyes in aqueous solutions.
    Matched MeSH terms: Light*
  6. Shaari, S., Ehsan, A.A., Abd-Rahman, M.K.
    ASM Science Journal, 2008;2(2):153-161.
    MyJurnal
    An optical code generating device for a portable optical access-card system was constructed using the plastic optical fibre (POF) waveguide coupler. The newly constructed device provided output light intensities which were used as optical codes in a portable optical access-card system. The construction of a basic 1 × 2 waveguide design combined two major components which were the asymmetric Y-junction splitter and the linear taper. A hollow waveguide structure was utilized as it provided more flexibility in guiding light rays. A basic 1 × 2 waveguide coupler was designed using the CAD tool and then the ray was traced using the non-sequential ray tracing tool. A linear relationship between the tap-off ratio and the waveguide tap-width enabled a higher-level hollow waveguide coupler to be designed using the simple cascading technique. Construction of a 1 × 4 and higher level waveguide coupler was easily realized using the basic 1 × 2 waveguide coupler design together with a simple cascading technique.
    Matched MeSH terms: Light
  7. Ooi CH, Talib MR
    Sci Rep, 2016 08 30;6:32056.
    PMID: 27571644 DOI: 10.1038/srep32056
    We report on some interesting phenomena in the focusing and scattering of femtosecond laser pulses in free space that provide insights on intense laser plasma interactions. The scattered image in the far field is analyzed and the connection with the observed structure of the plasma at the focus is discussed. We explain the physical mechanisms behind the changes in the colorful and intricate image formed by scattering from the plasma for different compressions, as well as orientations of plano-convex lens. The laser power does not show significant effect on the images. The pulse repetition rate above 500 Hz can affect the image through slow dynamics The spectrum of each color in the image shows oscillatory peaks due to interference of delayed pulse that correlate with the plasma length. Spectral lines of atomic species are identified and new peaks are observed through the white light emitted by the plasma spot. We find that an Ar gas jet can brighten the white light of the plasma spot and produce high resolution spectral peaks. The intricate image is found to be extremely sensitive and this is useful for applications in sensing microscale objects.
    Matched MeSH terms: Light
  8. Norlen, M., Mohammad Fadhi, M.Y., Ilhamah, O., Noradrenalina, I., Wahida, A.B., Noor Faradila, P.
    MyJurnal
    Introduction: To determine the effectiveness of the enhance enforcement programmes (The Ops) on the percentage of seatbelt wearing among front occupants in Malaysia.
    Methodology: The roadside observations for measuring the seatbelt wearing among front occupant were conducted before, two weeks and six months after the Ops. The study was conducted in selected states representing four different zones (Northern, Southern, Eastern and Central zones) of Peninsular Malaysia.
    Result: A total of 12,298 drivers and 11,212 front occupants were observed for their seatbelt wearing status through out the study. Percentage of seatbelt wearing among drivers and front passengers were increased from the baseline of 82.6 % and 74.4 % to 92 % (95 % CI: 91.2, 92.7) and 87.0 % (95 % CI: 85.9, 88.0) after two week, but declined to 85.7 % (95 % CI: 84.4, 86.8) and 76.8 % (95 % CI: 75.2, 78.3) after six months of the Ops respectively. Pre and post analysis revealed that after 2 weeks, the Ops were significantly effective in increasing the seatbelt wearing among front passengers and drivers with the RR (95 % CI) of 1.17 (1.14, 1.20) and 1.12 (1.10,1.13) respectively. However, after six months, the effectiveness of the Ops was reduced for both type of vehicle occupant.
    Conclusion: This study sheds light on the importance of the enhance enforcement programme for increasing the seatbelt wearing in Malaysia. However, in order to give more impact on seatbelt wearing, the strategy and the frequency of the enhance enforcement programme in Malaysia may need to be revised.
    Matched MeSH terms: Light
  9. Mohamed MA, W Salleh WN, Jaafar J, Mohd Hir ZA, Rosmi MS, Abd Mutalib M, et al.
    Carbohydr Polym, 2016 08 01;146:166-73.
    PMID: 27112862 DOI: 10.1016/j.carbpol.2016.03.050
    Visible light driven C-doped mesoporous TiO2 (C-MTiO2) nanorods have been successfully synthesized through green, low cost, and facile approach by sol-gel bio-templating method using regenerated cellulose membrane (RCM) as nanoreactor. In this study, RCM was also responsible to provide in-situ carbon sources for resultant C-MTiO2 nanorods in acidified sol at low temperatures. The composition, crystallinity, surface area, morphological structure, and optical properties of C-MTiO2 nanorods, respectively, had been characterized using FTIR, XRD, N2 adsorption/desorption, TEM, UV-vis-NIR, and XPS spectroscopy. The results suggested that the growth of C-MTiO2 nanorods was promoted by the strong interaction between the hydroxyl groups of RCMs and titanium ion. Optical and XPS analysis confirmed that carbon presence in TiO2 nanorods were responsible for band-gap narrowing, which improved the visible light absorption capability. Photocatalytic activity measurements exhibited the capability of C-MTiO2 nanorods in degradation of methyl orange in aqueous solution, with 96.6% degradation percentage under visible light irradiation.
    Matched MeSH terms: Light*
  10. Hanna R, Dalvi S, Amaroli A, De Angelis N, Benedicenti S
    J Biophotonics, 2021 01;14(1):e202000267.
    PMID: 32857463 DOI: 10.1002/jbio.202000267
    A present, photobiomodulation therapy (PBMT) effectiveness in enhancing bone regeneration in bone defects grafted with or without biomaterials is unclear. This systematic review (PROSPERO, ref. CRD 42019148959) aimed to critically appraise animal in vivo published data and present the efficacy of PBMT and its potential synergistic effects on grafted bone defects. MEDLINE, CCCT, Scopus, Science Direct, Google Scholar, EMBASE, EBSCO were searched, utilizing the following keywords: bone repair; low-level laser therapy; LLLT; light emitting diode; LEDs; photobiomodulation therapy; in vivo animal studies, bone substitutes, to identify studies between 1994 and 2019. After applying the eligibility criteria, 38 papers included where the results reported according to "PRISMA." The results revealed insufficient and incomplete PBM parameters, however, the outcomes with or without biomaterials have positive effects on bone healing. In conclusion, in vivo animal studies with a standardized protocol to elucidate the effects of PBMT on biomaterials are required initially prior to clinical studies.
    Matched MeSH terms: Low-Level Light Therapy*
  11. Jawad MM, Husein A, Alam MK, Hassan R, Shaari R
    Lasers Med Sci, 2014 Jan;29(1):367-72.
    PMID: 22986701 DOI: 10.1007/s10103-012-1199-8
    The need for orthodontic treatment is increasing all the time. As the treatment is time consuming ranging from a year to several years, any method of reducing the period of treatment and increasing the quality of the tissue will be beneficial to patients. The use of non-invasive techniques such as low level laser therapy and low intensity pulsed ultasound in accelerating orthodontic tooth movement are promising. Thus, this overview study will help to generate more understanding about the background information and the possible applications of them in daily orthodontics, depending on previous literature searching for reviews and original research articles.
    Matched MeSH terms: Low-Level Light Therapy/methods*; Low-Level Light Therapy/trends
  12. Teo CL, Idris A, Zain NAM, Taisir M
    Bioresour Technol, 2014 Dec;173:284-290.
    PMID: 25310864 DOI: 10.1016/j.biortech.2014.09.110
    In the study, the relationship between the quality and intensity of LED illumination with FAMEs produced were investigated. Nannochloropsis sp. was cultivated for 14 days under different intensities of 100, 150 and 200 μmol photons m(-2) s(-1) of red, blue and mixed red blue LED. The findings revealed that suitable combination of LED wavelengths and intensity; (red LED: 150, blue: 100 and mixed red blue: 200 μmol photons m(-2) s(-1)) produced maximum biomass growth and lipid content. It was observed that the quality and intensity of LED significantly influenced the composition of FAMEs. FAMEs produced under blue LED has high degree of unsaturation (DU) and low cetane number while those under red LED has low DU but higher CN. The combination of red blue LED has produced FAMEs with high ignition and lubricating property and also good oxidation stability indicated by the DU and CN values which lies midway between the red and blue.
    Matched MeSH terms: Light*
  13. Lee WC, Khoo BE, Bin Abdullah AF, Abdul Aziz ZB
    J Forensic Sci, 2013 May;58(3):658-63.
    PMID: 23488634 DOI: 10.1111/1556-4029.12103
    Bloodstain photography is important in forensic applications, especially for bloodstain pattern analysis. This study compares the enhancement effect of bloodstain photography using three different types of light source: fluorescent white light, near-ultraviolet (UV) light-emitting diode (LED) light, and 410 nm LED light. Randomized complete block designs were implemented to identify the lighting that would statistically produce the best enhancement results for bloodstains on different types of surfaces. Bloodstain samples were prepared on white cotton, brown carpet, tar road, and wood. These samples were photographed in darkroom conditions using a Canon EOS 50D digital SLR camera, with Canon EFS 60 mm f/2.8 Macro USM lens. Two-way analysis of variance and Fisher's least significant difference test were used to analyze the contrast of the images. The statistical analysis showed that 410 nm light is the best among the tested lights for enhancing bloodstains on the tested surfaces, where the contrast of bloodstain to background was the highest.
    Matched MeSH terms: Light*
  14. Kamal A, Salman B, Ar NH, Samsudin AR
    Clin Oral Investig, 2021 Mar;25(3):1029-1033.
    PMID: 32562076 DOI: 10.1007/s00784-020-03393-3
    OBJECTIVE: The aim of this study is to investigate the efficacy of delivering low-level laser therapy (LLLT) in the management of dry socket at University Dental Hospital Sharjah.

    MATERIALS AND METHOD: Forty-five patients with dry socket were divided into two treatment groups. Group I dry socket patients (n = 30) received conventional treatment while group II patients (n = 15) were irradiated with LLLT at a setting of 200-mW, 6-J, continuous-wave mode using an R02 tipless handpiece (Fotona Er:YAG, Europe), on the buccal, lingual, and middle surfaces of the socket for 30 s from a delivery distance of 1 cm. Pain score and quantification of granulation tissue in the socket were recorded at 0, 4, and 7 days post-dry socket treatment.

    RESULTS: Results showed that the LLLT-irradiated group II sockets showed a much lower VAS pain score of 1-2 as early as day 4, and a richer amount of granulation tissue compared to the conventional treated group I socket. The amount and rate of granulation tissue formation in the dry socket are inversely proportional to the pain score showing significant clinical effectiveness of LLLT on promoting the healing of the dry socket, with improvement in symptoms (P = .001). Conventionally treated dry sockets take at least 7 days to match the effective healing of an LLLT-irradiated dry socket.

    CONCLUSION: LLLT irradiation influences biomodulation of dry socket healing by dampening inflammation, promoting vascularization, stimulating granulation, and controlling pain symptoms.

    CLINICAL RELEVANCE: LLLT may be an additional effective tool for managing dry sockets in general dental practice.

    Matched MeSH terms: Low-Level Light Therapy*
  15. Bugge AN, Sauge S, Ghazali AM, Skaar J, Lydersen L, Makarov V
    Phys Rev Lett, 2014 Feb 21;112(7):070503.
    PMID: 24579579
    We propose a class of attacks on quantum key distribution (QKD) systems where an eavesdropper actively engineers new loopholes by using damaging laser illumination to permanently change properties of system components. This can turn a perfect QKD system into a completely insecure system. A proof-of-principle experiment performed on an avalanche photodiode-based detector shows that laser damage can be used to create loopholes. After ∼1  W illumination, the detectors' dark count rate reduces 2-5 times, permanently improving single-photon counting performance. After ∼1.5  W, the detectors switch permanently into the linear photodetection mode and become completely insecure for QKD applications.
    Matched MeSH terms: Light; Lighting
  16. Tan LL, Ong WJ, Chai SP, Mohamed AR
    Chem Commun (Camb), 2014 Jul 4;50(52):6923-6.
    PMID: 24841282 DOI: 10.1039/c4cc01304b
    A facile and dopant-free strategy was employed to fabricate oxygen-rich TiO2 (O2-TiO2) with enhanced visible light photoactivity. Such properties were achieved by the in situ generation of oxygen through the thermal decomposition of the peroxo-titania complex. The O2-TiO2 photocatalyst exhibited high photoactivity towards CO2 reduction under visible light.
    Matched MeSH terms: Light
  17. Lim J, Yeap SP, Che HX, Low SC
    Nanoscale Res Lett, 2013;8(1):381.
    PMID: 24011350 DOI: 10.1186/1556-276X-8-381
    Here we provide a complete review on the use of dynamic light scattering (DLS) to study the size distribution and colloidal stability of magnetic nanoparticles (MNPs). The mathematical analysis involved in obtaining size information from the correlation function and the calculation of Z-average are introduced. Contributions from various variables, such as surface coating, size differences, and concentration of particles, are elaborated within the context of measurement data. Comparison with other sizing techniques, such as transmission electron microscopy and dark-field microscopy, revealed both the advantages and disadvantages of DLS in measuring the size of magnetic nanoparticles. The self-assembly process of MNP with anisotropic structure can also be monitored effectively by DLS.
    Matched MeSH terms: Dynamic Light Scattering
  18. Jalil MA, Phelawan J, Aziz MS, Saktioto T, Ong CT, Yupapin PP
    Artif Cells Nanomed Biotechnol, 2013 Apr;41(2):92-7.
    PMID: 22991968 DOI: 10.3109/10731199.2012.700519
    Acne vulgaris is adebilitating dermatologic disease, and is conventionally treated by laser therapy using a microring resonator system. An evolving understanding of laser-tissue interactions involving Propioni bacterium acneproducing porphyrins, and the development of lasers to target the sebaceous glands, has led to the development of an escalating number of laser light for acne treatment. The results show that the full width at half maximum of the proposed laser pulse of 0.15 nm can be generated using a microring resonator system. The power of the laser is 200 W and the wavelength laser is 1,032 nm, which is proposed as a treatment of acne vulgaris diseases.
    Matched MeSH terms: Light; Low-Level Light Therapy/instrumentation*; Low-Level Light Therapy/methods*
  19. Ismail MA, Harun SW, Zulkepely NR, Nor RM, Ahmad F, Ahmad H
    Appl Opt, 2012 Dec 20;51(36):8621-4.
    PMID: 23262603 DOI: 10.1364/AO.51.008621
    We demonstrate a simple and low cost mode-locked erbium-doped fiber laser (EDFL) operating in the nanosecond region using a single-walled carbon nanotube (SWCNT)-based saturable absorber (SA). A droplet of SWCNT solution is applied on the end of a fiber ferrule, which is then mated to another clean connector ferrule to construct an SA. Then the SA is integrated into a ring EDFL cavity for nanosecond pulse generation. The EDFL operates at around 1570.4 nm, with a soliton-like spectrum with small Kelly sidebands, which confirms the attainment of the anomalous dispersion. It produces a soliton pulse train with a 332 ns width, repetition rate of 909.1 kHz, an average output power of 0.31 mW, and energy of 0.34 nJ at the maximum pump power of 130.8 mW.
    Matched MeSH terms: Light
  20. Ahmad H, Latif AA, Abdul Khudus MI, Zulkifli AZ, Zulkifli MZ, Thambiratnam K, et al.
    Appl Opt, 2013 Feb 1;52(4):818-23.
    PMID: 23385923 DOI: 10.1364/AO.52.000818
    A highly stable tunable dual-wavelength fiber laser (TDWFL) using graphene as a means to generate a highly stable output is proposed and generated. The TDWFL comprises a 1 m long, highly doped erbium-doped fiber (EDF) acting as the linear gain medium, with a 24-channel arrayed waveguide grating acting as a wavelength slicer as well as a tuning mechanism to generate different wavelength pairs. The tuned wavelength pairs can range from 0.8 to 18.2 nm. A few layers of graphene are incorporated into the laser cavity to induce the four-wave-mixing effect, which stabilizes the dual-wavelength output by suppressing the mode competition that arises as a result of homogenous broadening in the EDF.
    Matched MeSH terms: Light
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