Displaying publications 1 - 20 of 337 in total

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  1. Ikram M, Hayat S, Imran M, Haider A, Naz S, Ul-Hamid A, et al.
    Carbohydr Polym, 2021 Oct 01;269:118346.
    PMID: 34294353 DOI: 10.1016/j.carbpol.2021.118346
    In the present study, the novel Ag/cellulose nanocrystal (CNC)-doped CeO2 quantum dots (QDs) with highly efficient catalytic performance were synthesized using one pot co-precipitation technique, which were then applied in the degradation of methylene blue and ciprofloxacin (MBCF) in wastewater. Catalytic activity against MBCF dye was significantly reduced (99.3%) for (4%) Ag dopant concentration in acidic medium. For Ag/CNC-doped CeO2 vast inhibition domain of G-ve was significantly confirmed as (5.25-11.70 mm) and (7.15-13.60 mm), while medium- to high-concentration of CNC levels were calculated for G + ve (0.95 nm, 1.65 mm), respectively. Overall, (4%) Ag/CNC-doped CeO2 revealed significant antimicrobial activity against G-ve relative to G + ve at both concentrations, respectively. Furthermore, in silico molecular docking studies were performed against selected enzyme targets dihydrofolate reductase (DHFR), dihydropteroate synthase (DHPS), and DNA gyrase belonging to folate and nucleic acid biosynthetic pathway, respectively to rationalize possible mechanism behind bactericidal potential of CNC-CeO2 and Ag/CNC-CeO2.
    Matched MeSH terms: Light
  2. Thanh T, Chi VT, Abdullah MP, Omar H, Noroozi M, Napis S
    Mol Biol Rep, 2011 Nov;38(8):5297-305.
    PMID: 21287365 DOI: 10.1007/s11033-011-0679-4
    An initial study on gene cloning and characterization of unicellular green microalga Ankistrodesmus convolutus was carried out to isolate and characterize the full-length cDNA of ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit (RbcS) as a first step towards elucidating the structure of A. convolutus RbcS gene. The full-length of A. convolutus RbcS cDNA (AcRbcS) contained 28 bp of 5' untranslated region (UTR), 225 bp of 3' non-coding region, and an open reading frame of 165 amino acids consisting of a chloroplast transit peptide with 24 amino acids and a mature protein of 141 amino acids. The amino acid sequence has high identity to those of other green algae RbcS genes. The AcRbcS contained a few conserved domains including protein kinase C phosphorylation site, tyrosine kinase phosphorylation site and N-myristoylation sites. The AcRbcS was successfully expressed in Escherichia coli and a ~21 kDa of anticipated protein band was observed on SDS-PAGE. From the phylogenetic analysis of RbcS protein sequences, it was found that the RbcS of A. convolutus has closer genetic relationship with green microalgae species compared to those of green seaweed and green macroalgae species. Southern hybridization analysis revealed that the AcRbcS is a member of a small multigene family comprising of two to six members in A. convolutus genome. Under different illumination conditions, RT-PCR analysis showed that AcRbcS transcription was reduced in the dark, and drastically recovered in the light condition. Results presented in this paper established a good foundation for further study on the photosynthetic process of A. convolutus and other green algae species where little information is known on Rubisco small subunit.
    Matched MeSH terms: Light
  3. Razak AA, Harrison A
    J Prosthet Dent, 1997 Apr;77(4):353-8.
    PMID: 9104710
    Dimensional accuracy of a composite inlay restoration is important to ensure an accurate fit and to minimize cementation stresses.
    Matched MeSH terms: Light
  4. Badran MM, Alomrani AH, Harisa GI, Ashour AE, Kumar A, Yassin AE
    Biomed Pharmacother, 2018 Oct;106:1461-1468.
    PMID: 30119220 DOI: 10.1016/j.biopha.2018.07.102
    In the present study, docetaxel (DTX)-loaded poly(lactic-co-glycolic acid) (PLGA) and polycaprolactone (PCL) nanoparticles were successfully prepared and coated with chitosan (CS). The prepared nanoparticles (NPs) were evaluated for their particle size, zeta potential, particle morphology, drug entrapment efficiency (EE%), and in vitro drug release profile. The anticancer activity of DTX-loaded NPs was assessed in human HT29 colon cancer cell line utilizing MTT assay. The pharmacokinetics of DTX-loaded NPs was monitored in Wistar rats in comparison to DTX solution. The prepared NPs exhibited particle sizes in the range 177.1 ± 8.2-287.6 ± 14.3 nm. CS decorated NPs exhibited a significant increase in particle size and a switch of zeta potential from negative to positive. In addition, high EE% values were obtained for CS coated PCL NPs and PLGA NPs as 67.1 and 76.2%, respectively. Moreover, lowering the rate of DTX in vitro release was achieved within 48 h by using CS coated NPs. Furthermore, a tremendous increase in DTX cytotoxicity was observed by CS-decorated PLGA NPs compared to all other NPs including DTX-free-NPs and pure DTX. The in vivo study revealed significant enhancement in DTX bioavailability from CS-decorated PLGA NPs with more than 4-fold increase in AUC compared to DTX solution. In conclusion, CS-decorated PLGA NPs are a considerable DTX-delivery carrier with magnificent antitumor efficacy.
    Matched MeSH terms: Dynamic Light Scattering
  5. Lim SH, Lee HB, Ho AS
    Photochem Photobiol, 2011 Sep-Oct;87(5):1152-8.
    PMID: 21534974 DOI: 10.1111/j.1751-1097.2011.00939.x
    In our screening for photosensitizers from natural resources, 15(1)-hydroxypurpurin-7-lactone ethyl methyl diester (compound 1) was isolated for the first time from an Araceae plant. To evaluate the efficacy of compound 1 as a photosensitizer for head and neck cancers, compound 1 was studied in reference to a known photosensitizer pheophorbide-a (Pha), in terms of photophysical properties, singlet oxygen generation and in in vitro experiments (intracellular uptake and phototoxicity assays) in two oral (HSC2 and HSC3) and two nasopharyngeal (HK1 and C666-1) cancer cell lines. In this study, compound 1 exhibited higher intracellular uptake over 24 h compared with Pha in both HSC3 and HK1 cells. When activated by ≥4.8 J cm(-2) of light, compound 1 was slightly more potent as a photosensitizer than Pha by consistently having marginally lower IC(50) values across different cell lines. In flow cytometry experiments to study the mechanism of photoactivated cell death in HSC3, compound 1 was observed to induce more pronounced apoptosis compared with Pha, which may have been driven by the transient G(2)/M cell cycle block which was also observed. These promising results on compound 1 warrant its further investigation as a clinically useful photodynamic therapy agent for head and neck cancer.
    Matched MeSH terms: Light
  6. Nath RK, Zain MF, Kadhum AA
    ScientificWorldJournal, 2013;2013:686497.
    PMID: 24376384 DOI: 10.1155/2013/686497
    The addition of a photocatalyst to ordinary building materials such as concrete creates environmentally friendly materials by which air pollution or pollution of the surface can be diminished. The use of LiNbO3 photocatalyst in concrete material would be more beneficial since it can produce artificial photosynthesis in concrete. In these research photoassisted solid-gas phases reduction of carbon dioxide (artificial photosynthesis) was performed using a photocatalyst, LiNbO3, coated on concrete surface under illumination of UV-visible or sunlight and showed that LiNbO3 achieved high conversion of CO2 into products despite the low levels of band-gap light available. The high reaction efficiency of LiNbO3 is explained by its strong remnant polarization (70 µC/cm(2)), allowing a longer lifetime of photoinduced carriers as well as an alternative reaction pathway. Due to the ease of usage and good photocatalytic efficiency, the research work done showed its potential application in pollution prevention.
    Matched MeSH terms: Light
  7. Ravera S, Ferrando S, Agas D, De Angelis N, Raffetto M, Sabbieti MG, et al.
    J Biophotonics, 2019 09;12(9):e201900101.
    PMID: 31033186 DOI: 10.1002/jbio.201900101
    Photobiomodulation (PBM) is a non-plant-cell manipulation through a transfer of energy by means of light sources at the non-ablative or thermal intensity. Authors showed that cytochrome-c-oxidase (complex IV) is the specific chromophore's target of PBM at the red (600-700 nm) and NIR (760-900 nm) wavelength regions. Recently, it was suggested that the infrared region of the spectrum could influence other chromospheres, despite the interaction by wavelengths higher than 900 nm with mitochondrial chromophores was not clearly demonstrated. We characterized the interaction between mitochondria respiratory chain, malate dehydrogenase, a key enzyme of Krebs cycle, and 3-hydroxyacyl-CoA dehydrogenase, an enzyme involved in the β-oxidation (two mitochondrial matrix enzymes) with the 1064 nm Nd:YAG (100mps and 10 Hz frequency mode) irradiated at the average power density of 0.50, 0.75, 1.00, 1.25 and 1.50 W/cm2 to generate the respective fluences of 30, 45, 60, 75 and 90 J/cm2 . Our results show the effect of laser light on the transmembrane mitochondrial complexes I, III, IV and V (adenosine triphosphate synthase) (window effects), but not on the extrinsic mitochondrial membrane complex II and mitochondria matrix enzymes. The effect is not due to macroscopical thermal change. An interaction of this wavelength with the Fe-S proteins and Cu-centers of respiratory complexes and with the water molecules could be supposed.
    Matched MeSH terms: Low-Level Light Therapy
  8. Keck CM
    Int J Pharm, 2010 May 5;390(1):3-12.
    PMID: 19733647 DOI: 10.1016/j.ijpharm.2009.08.042
    The influence of optical parameters, additional techniques (e.g. PIDS technology) and the importance of light microscopy were investigated by comparing laser diffraction data obtained via the conventional method and an optimized analysis method. Also the influence of a possible dissolution of nanocrystals during a measurement on the size result obtained was assessed in this study. The results reveal that dissolution occurs if unsaturated medium or microparticle saturated medium is used for the measurements. The dissolution is erratic and the results are not reproducible. Dissolution can be overcome by saturating the measuring medium prior to the measurement. If nanocrystals are analysed the dispersion medium should be saturated with the nanocrystals, because the solubility is higher than for coarse micro-sized drug material. The importance of using the optimized analysis method was proven by analysing 40 different nanosuspensions via the conventional versus the optimized sizing method. There was no large difference in the results obtained for the 40 nanosuspensions using the conventional method. This would have led to the conclusion, that all the 40 formulations investigated are physically stable. However, the analysis via the optimized method revealed that from 40 formulations investigated only four were physically stable. In conclusion an optimized analysis saves time and money and avoids misleading developments, because discrimination between "stable" and "unstable" can be done reliably at a very early stage of the development.
    Matched MeSH terms: Light
  9. Siriviriyanun A, Tsai YJ, Voon SH, Kiew SF, Imae T, Kiew LV, et al.
    Mater Sci Eng C Mater Biol Appl, 2018 Aug 01;89:307-315.
    PMID: 29752102 DOI: 10.1016/j.msec.2018.04.020
    In this study, nanohybrid materials consisting of graphene oxide (GO), β‑cyclodextrin (CD) and poly(amido amine) dendrimer (DEN) were successfully prepared by covalent bonding. GO-CD and GO-CD-DEN were found to be potential nanocarriers for anticancer drugs including chemotherapeutics (doxorubicin (DOX), camptothecin (CPT)) and photosensitizer (protoporphyrin IX (PpIX)). GO-CD possessed 1.2 times higher DOX-loading capacity than GO due to inclusion of additional DOX to the CD. The drug loading on GO-CD-DEN increased in the order: DOX 
    Matched MeSH terms: Light
  10. Ebadi M, Saifullah B, Buskaran K, Hussein MZ, Fakurazi S
    Int J Nanomedicine, 2019;14:6661-6678.
    PMID: 31695362 DOI: 10.2147/IJN.S214923
    Background: Cancer treatments are being continually developed. Increasingly more effective and better-targeted treatments are available. As treatment has developed, the outcomes have improved.

    Purpose: In this work, polyethylene glycol (PEG), layered double hydroxide (LDH) and 5-fluorouracil (5-FU) were used as a stabilizing agent, a carrier and an anticancer active agent, respectively.

    Characterization and methods: Magnetite nanoparticles (Fe3O4) coated with polyethylene glycol (PEG) and co-coated with 5-fluorouracil/Mg/Al- or Zn/Al-layered double hydroxide were synthesized by co-precipitation technique. Structural, magnetic properties, particle shape, particle size and drug loading percentage of the magnetic nanoparticles were investigated by XRD, TGA, FTIR, DLS, FESEM, TEM, VSM, UV-vis spectroscopy and HPLC techniques.

    Results: XRD, TGA and FTIR studies confirmed the formation of Fe3O4 phase and the presence of iron oxide nanoparticles, polyethylene glycol, LDH and the drug for all the synthesized samples. The size of the nanoparticles co-coated with Mg/Al-LDH is about 27 nm compared to 40 nm when they were co-coated with Zn/Al-LDH, with both showings near uniform spherical shape. The iron oxide nanoparticles retain their superparamagnetic property when they were coated with polyethylene glycol, polyethylene glycol co-coated with Mg/Al-LDH and polyethylene glycol co-coated with Zn/Al-LDH with magnetic saturation value of 56, 40 and 27 emu/g, respectively. The cytotoxicity study reveals that the anticancer nanodelivery system has better anticancer activity than the free drug, 5-FU against liver cancer HepG2 cells and at the same time, it was found to be less toxic to the normal fibroblast 3T3 cells.

    Conclusion: These are unique core-shell nanoparticles synthesized with the presence of multiple functionalities are hoped can be used as a multifunctional nanocarrier with the capability of targeted delivery using an external magnetic field and can also be exploited as hypothermia for cancer cells in addition to the chemotherapy property.

    Matched MeSH terms: Dynamic Light Scattering
  11. Hariharan D, Thangamuniyandi P, Jegatha Christy A, Vasantharaja R, Selvakumar P, Sagadevan S, et al.
    J. Photochem. Photobiol. B, Biol., 2020 Jan;202:111636.
    PMID: 31739259 DOI: 10.1016/j.jphotobiol.2019.111636
    Titanium dioxide (TiO2) nanoparticles (NPs) have been doped with varying amounts (0.005, 0.010 and 0.015 M) of silver nanoparticles (Ag NPs) using hydrothermal method. Further, in this work, a green approach was followed for the formation of Ag@TiO2 NPs using Aloe vera gel as a capping and reducing agent. The structural property confirmed the presence of anatase phase TiO2. Increased peak intensity was observed while increasing the Ag concentration. Further, the morphological and optical properties have been studied, which confirmed the effective photocatalytic behavior of the prepared Ag@TiO2 NPs. The photocatalytic performance of Ag@TiO2 has been considered for the degradation of picric acid in the visible light region. The concentration at 0.010 M of the prepared Ag@TiO2 has achieved higher photocatalytic performance within 50 min, which could be attributed to its morphological behavior. Similarly, anticancer activity against lung cancer cell lines (A549) was also determined. The Ag@TiO2 NPs generated a large quantity of reactive oxygen species (ROS), resulting in complete cancer cell growth suppression after their systemic in vitro administration. Ag@TiO2 NPs was adsorbed visible light that leads to an enhanced anticancer sensitivity by killing and inhibiting cancer cell reproduction through cell viability assay test. It was clear that 0.015 M of Ag@TiO2 NPs were highly effective against human lung cancer cell lines and showed increased production of ROS in cancer cell lines due to the medicinal behavior of the Aloe vera gel.
    Matched MeSH terms: Light
  12. Chew HP, Zakian CM, Pretty IA, Ellwood RP
    Caries Res, 2014;48(3):254-62.
    PMID: 24481141 DOI: 10.1159/000354411
    BACKGROUND: Measurement of initial enamel erosion is currently limited to in vitro methods. Optical coherence tomography (OCT) and quantitative light-induced fluorescence (QLF) have been used clinically to study advanced erosion. Little is known about their potential on initial enamel erosion.

    OBJECTIVES: To evaluate the sensitivity of QLF and OCT in detecting initial dental erosion in vitro.

    METHODS: 12 human incisors were embedded in resin except for a window on the buccal surface. Bonding agent was applied to half of the window, creating an exposed and non-exposed area. Baseline measurements were taken with QLF, OCT and surface microhardness. Samples were immersed in orange juice for 60 min and measurements taken stepwise every 10 min. QLF was used to compare the loss of fluorescence between the two areas. The OCT system, OCS1300SS (Thorlabs Ltd.), was used to record the intensity of backscattered light of both areas. Multiple linear regression and paired t test were used to compare the change of the outcome measures.

    RESULTS: All 3 instruments demonstrated significant dose responses with the erosive challenge interval (p < 0.05) and a detection threshold of 10 min from baseline. Thereafter, surface microhardness demonstrated significant changes after every 10 min of erosion, QLF at 4 erosive intervals (20, 40, 50 and 60 min) while OCT at only 2 (50 and 60 min).

    CONCLUSION: It can be concluded that OCT and QLF were able to detect demineralization after 10 min of erosive challenge and could be used to monitor the progression of demineralization of initial enamel erosion in vitro.

    Matched MeSH terms: Light
  13. Zhang P, Wang P, Yan L, Liu L
    Int J Nanomedicine, 2018;13:7047-7059.
    PMID: 30464458 DOI: 10.2147/IJN.S180138
    BACKGROUND: Nasopharyngeal cancer (NPC) is one of the subtypes of head and neck cancers. It occurs rarely, and its prevalence depends mainly on geographical location. Modern-day research is focused on coupling nanotechnology and traditional medicine for combating cancers. Gold nanoparticles (AuNPs) were synthesized from Solanum xanthocarpum (Sx) leaf extract using reduction method.

    METHODS: Characterization of the synthesized AuNPs was done by different techniques such as ultraviolet-visible spectrum absorption, X-ray diffraction, dynamic light scattering, Fourier transform infrared spectroscopy, transmission electron microscopy, and energy-dispersive X-ray analysis.

    RESULTS: All the results showed the successful green synthesis of AuNPs from Sx, which induced apoptosis of C666-1 cell line (NPC cell line). There was a decline in both cell viability and colony formation in C666-1 cells upon treatment with Sx-AuNPs. The cell death was proved to be caused by autophagy and mitochondrial-dependent apoptotic pathway.

    CONCLUSION: Thus, due to their anticancer potential, these nanoparticles coupled with Sx can be used for in vivo applications and clinical research in future.

    Matched MeSH terms: Dynamic Light Scattering
  14. Chiu HI, Lim V
    Int J Nanomedicine, 2021;16:2995-3020.
    PMID: 33911862 DOI: 10.2147/IJN.S302238
    PURPOSE: In chemotherapy, oral administration of drug is limited due to lack of drug specificity for localized colon cancer cells. The inability of drugs to differentiate cancer cells from normal cells induces side effects. Colonic targeting with polymeric nanoparticulate drug delivery offers high potential strategies for delivering hydrophobic drugs and fewer side effects to the target site. Disulfide cross-linked polymers have recently acquired high significance due to their potential to degrade in reducing colon conditions while resisting the upper gastrointestinal tract's hostile environment. The goal of this project is, therefore, to develop pH-sensitive and redox-responsive fluorescein-labeled wheat germ agglutinin (fWGA)-mounted disulfide cross-linked alginate nanoparticles (fDTP2) directly targeting docetaxel (DTX) in colon cancer cells.

    METHODS: fDTP2 was prepared by mounting fWGA on DTX-loaded nanoparticles (DTP2) using the two-step carbodiimide method. Morphology of fDTP2 was examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Dynamic light scattering (DLS) study was carried out to determine the mean diameter, polydispersity index (PDI) and zeta potential of fDTP2. Cellular uptake efficiency was examined using fluorescence microplate reader. Biocompatibility and active internalization of fDTP2 were conducted on HT-29.

    RESULTS: fDTP2 was found to exhibit a DTX loading efficiency of 19.3%. SEM and TEM tests revealed spherical nanoparticles. The in vitro DTX release test showed a cumulative release of 54.7%. From the DLS study, fDTP2 reported a 277.7 nm mean diameter with PDI below 0.35 and -1.0 mV zeta potential. HT-29 which was fDTP2-treated demonstrated lower viability than L929 with a half maximal inhibitory concentration (IC50) of 34.7 µg/mL. HT-29 (33.4%) internalized fDTP2 efficiently at 2 h incubation. The study on HT-29 active internalization of nanoparticles through fluorescence and confocal imaging indicated such.

    CONCLUSION: In short, fDTP2 demonstrated promise as a colonic drug delivery DTX transporter.

    Matched MeSH terms: Dynamic Light Scattering
  15. Yusefi M, Shameli K, Su Yee O, Teow SY, Hedayatnasab Z, Jahangirian H, et al.
    Int J Nanomedicine, 2021;16:2515-2532.
    PMID: 33824589 DOI: 10.2147/IJN.S284134
    INTRODUCTION: Fe3O4 nanoparticles (Fe3O4 NPs) with multiple functionalities are intriguing candidates for various biomedical applications.

    MATERIALS AND METHODS: This study introduced a simple and green synthesis of Fe3O4 NPs using a low-cost stabilizer of plant waste extract rich in polyphenols content with a well-known antioxidant property as well as anticancer ability to eliminate colon cancer cells. Herein, Fe3O4 NPs were fabricated via a facile co-precipitation method using the crude extract of Garcinia mangostana fruit peel as a green stabilizer at different weight percentages (1, 2, 5, and 10 wt.%). The samples were analyzed for magnetic hyperthermia and then in vitro cytotoxicity assay was performed.

    RESULTS: The XRD planes of the samples were corresponding to the standard magnetite Fe3O4 with high crystallinity. From TEM analysis, the green synthesized NPs were spherical with an average size of 13.42±1.58 nm and displayed diffraction rings of the Fe3O4 phase, which was in good agreement with the obtained XRD results. FESEM images showed that the extract covered the surface of the Fe3O4 NPs well. The magnetization values for the magnetite samples were ranging from 49.80 emu/g to 69.42 emu/g. FTIR analysis verified the functional groups of the extract compounds and their interactions with the NPs. Based on DLS results, the hydrodynamic sizes of the Fe3O4 nanofluids were below 177 nm. Furthermore, the nanofluids indicated the zeta potential values up to -34.92±1.26 mV and remained stable during four weeks of storage, showing that the extract favorably improved the colloidal stability of the Fe3O4 NPs. In the hyperthermia experiment, the magnetic nanofluids showed the acceptable specific absorption rate (SAR) values and thermosensitive performances under exposure of various alternating magnetic fields. From results of in vitro cytotoxicity assay, the killing effects of the synthesized samples against HCT116 colon cancer cells were mostly higher compared to those against CCD112 colon normal cells. Remarkably, the Fe3O4 NPs containing 10 wt.% of the extract showed a lower IC50 value (99.80 µg/mL) in HCT116 colon cancer cell line than in CCD112 colon normal cell line (140.80 µg/mL).

    DISCUSSION: This research, therefore, introduced a new stabilizer of Garcinia mangostana fruit peel extract for the biosynthesis of Fe3O4 NPs with desirable physiochemical properties for potential magnetic hyperthermia and colon cancer treatment.

    Matched MeSH terms: Dynamic Light Scattering
  16. Ng MY, Tan WS, Tey BT
    PMID: 22819608 DOI: 10.1016/j.jchromb.2012.06.043
    Fusion M13 phage with disulfide constrained heptapeptide, C-WSFFSNI-C, inserted into the minor coat protein (gpIII), has been selected in the current study as ligand in direct purification of hepatitis B core antigen (HBcAg) from unclarified Escherichia coli (E. coli) feedstock. The selected fusion phage showed strong association with the surface of the core particle. In the present study, this fusion M13 phage was immobilized onto Streamline base matrix via epoxy activation and used as adsorbent to capture HBcAg from crude E. coli homogenate. The maximum binding capacity for the adsorbent was 3.76 mg/mL with equilibrium coefficient of 1.83 mg/mL. Due to the slow uptake rate of HBcAg by M13 phage-immobilized adsorbents, a modified EBAC operation with recirculation of feedstock into the expanded bed has been investigated in this study. The introduction of feedstock recirculation has led to an 18% increase in yield; however, the purity of the eluted product was reduced by 15% compared with typical EBAC operation. The level of antigenicity exhibited by the core particles purified by both EBAC operations employed in the present study was comparable to that purified using sucrose ultracentrifugation.
    Matched MeSH terms: Light
  17. Che HX, Yeap SP, Osman MS, Ahmad AL, Lim J
    ACS Appl Mater Interfaces, 2014 Oct 8;6(19):16508-18.
    PMID: 25198872 DOI: 10.1021/am5050949
    The synthesis of nanocomposite with controlled surface morphology plays a key role for pollutant removal from aqueous environments. The influence of the molecular size of the polyelectrolyte in synthesizing silica-iron oxide core-shell nanocomposite with open shell structure was investigated by using dynamic light scattering, atomic force microscopy, and quartz crystal microbalance with dissipation (QCM-D). Here, poly(diallydimethylammonium chloride) (PDDA) was used to promote the attachment of iron oxide nanoparticles (IONPs) onto the silica surface to assemble a nanocomposite with magnetic and catalytic bifunctionality. High molecular weight PDDA tended to adsorb on silica colloid, forming a more extended conformation layer than low molecular weight PDDA. Subsequent attachment of IONPs onto this extended PDDA layer was more randomly distributed, forming isolated islands with open space between them. By taking amoxicillin, an antibiotic commonly found in pharmaceutical waste, as the model system, better removal was observed for silica-iron oxide nanocomposite with a more extended open shell structure.
    Matched MeSH terms: Light
  18. Ibrahim MH, Jaafar HZ, Karimi E, Ghasemzadeh A
    ScientificWorldJournal, 2014;2014:360290.
    PMID: 24683336 DOI: 10.1155/2014/360290
    A split plot 3 by 4 experiment was designed to investigate and distinguish the relationships among production of secondary metabolites, soluble sugar, phenylalanine ammonia lyase (PAL; EC 4.3.1.5) activity, leaf gas exchange, chlorophyll content, antioxidant activity (DPPH), and lipid peroxidation under three levels of CO2 (400, 800, and 1200 μ mol/mol) and four levels of light intensity (225, 500, 625, and 900 μ mol/m(2)/s) over 15 weeks in Labisia pumila. The production of plant secondary metabolites, sugar, chlorophyll content, antioxidant activity, and malondialdehyde content was influenced by the interactions between CO2 and irradiance. The highest accumulation of secondary metabolites, sugar, maliondialdehyde, and DPPH activity was observed under CO2 at 1200 μ mol/mol + light intensity at 225 μ mol/m(2)/s. Meanwhile, at 400 μ mol/mol CO2 + 900 μ mol/m(2)/s light intensity the production of chlorophyll and maliondialdehyde content was the highest. As CO2 levels increased from 400 to 1200 μ mol/mol the photosynthesis, stomatal conductance, f v /f m (maximum efficiency of photosystem II), and PAL activity were enhanced. The production of secondary metabolites displayed a significant negative relationship with maliondialdehyde indicating lowered oxidative stress under high CO2 and low irradiance improved the production of plant secondary metabolites that simultaneously enhanced the antioxidant activity (DPPH), thus improving the medicinal value of Labisia pumila under this condition.
    Matched MeSH terms: Light
  19. Ng SM, Wong DS, Phung JH, Chin SF, Chua HS
    Talanta, 2013 Nov 15;116:514-9.
    PMID: 24148438 DOI: 10.1016/j.talanta.2013.07.031
    Quantum dots are fluorescent semiconductor nanoparticles that can be utilised for sensing applications. This paper evaluates the ability to leverage their analytical potential using an integrated fluorescent sensing probe that is portable, cost effective and simple to handle. ZnO quantum dots were prepared using the simple sol-gel hydrolysis method at ambient conditions and found to be significantly and specifically quenched by copper (II) ions. This ZnO quantum dots system has been incorporated into an in-house developed miniature fluorescent probe for the detection of copper (II) ions in aqueous medium. The probe was developed using a low power handheld black light as excitation source and three photo-detectors as sensor. The sensing chamber placed between the light source and detectors was made of 4-sided clear quartz windows. The chamber was housed within a dark compartment to avoid stray light interference. The probe was operated using a microcontroller (Arduino Uno Revision 3) that has been programmed with the analytical response and the working algorithm of the electronics. The probe was sourced with a 12 V rechargeable battery pack and the analytical readouts were given directly using a LCD display panel. Analytical optimisations of the ZnO quantum dots system and the probe have been performed and further described. The probe was found to have a linear response range up to 0.45 mM (R(2)=0.9930) towards copper (II) ion with a limit of detection of 7.68×10(-7) M. The probe has high repeatable and reliable performance.
    Matched MeSH terms: Light
  20. Kamal N, Sabaratnam V, Abdullah N, Ho AS, Teo SH, Lee HB
    Antonie Van Leeuwenhoek, 2009 Feb;95(2):179-88.
    PMID: 19125347 DOI: 10.1007/s10482-008-9301-8
    Photodynamic therapy (PDT) is a promising cancer treatment which involves activation of a photosensitizing drug with light to produce reactive oxygen species that kill tumors without causing damage to unirradiated normal tissues. To date, only Photofrin, Foscan and Levulan have been approved for clinical treatment of cancer. Tropical habitats such as those found in Malaysia are attractive sources of new therapeutic compounds as tremendous chemical diversity is found in a large number of plants, animals, marine- and micro-organisms. In our screening program for novel photosensitizers from nature, colorful strains of fungi (from Aspergillus and Penicillium genus) and bacteria (including actinomycetes and photosynthetic bacteria) were collected from various habitats in Peninsular Malaysia, such as coastal soil, peat soil, marine sponges and wastewater ponds. Methanolic extracts from a total of 85 different species were evaluated with a short-term cell viability assay for photo-cytotoxicity, where a promyelocytic leukemia cell-line, HL60 incubated with 20 microg/ml of extracts was irradiated with 9.6 J/cm(2) of a broad spectrum light. Two of these extracts, one from Rhodobacter sphaeroides (PBUM003) and one from Rhodopseudomonas palustris (PBUM001) showed moderate to strong photo-cytotoxicity. Subsequent bioassay guided isolation of the PBUM001 extract yielded known photosensitisers that are based on bacteriochlorophyll-a by comparing their molecular weight data, HPLC profiles and UV-vis absorption spectra with literature values, thereby demonstrating the validity of our screening approach.
    Matched MeSH terms: Light
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