Displaying publications 301 - 320 of 622 in total

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  1. Effect of co-doping of sodium on the thermoluminescence dosimetry properties of copper-doped zinc lithium borate glass system
    Saidu A, Wagiran H, Saeed MA, Alajerami YSM, Kadir ABA
    Appl Radiat Isot, 2016 Dec;118:375-381.
    PMID: 27894049 DOI: 10.1016/j.apradiso.2016.10.005
    The effect of sodium as a co-dopant on the thermoluminescence (TL) properties of copper-doped zinc lithium borate (ZLB: Cu) subjected to Co-60 gamma radiation is reported in this study. TL intensity is enhanced with the introduction of sodium in ZLB: Cu. The obtained glow curve is simple with a single peak. The annealing procedure and the best heating rate for the proposed thermoluminescent dosimeter (TLD) are established, and the phosphor is reusable. The TL response within the dose range of 0.5-1000Gy is investigated. The results show that the thermal fading behaviour is improved significantly.
    Matched MeSH terms: Zinc
  2. Fulltext Effect of Preservative Pretreatment on the Biological Durability of Corn Straw Fiber/HDPE Composites
    Xuan L, Hui D, Cheng W, Wong AHH, Han G, Tan WK, et al.
    Materials (Basel), 2017 Jul 12;10(7).
    PMID: 28773150 DOI: 10.3390/ma10070789
    The effects of alkaline copper quaternary (ACQ) and zinc borate (ZB) on the resistance of corn stalk fiber (CSF)-reinforced high-density polyethylene (HDPE) composites to biodegradation were examined. Both biocides could inhibit termites, mold fungi, and wood-decay fungi, even at high CSF formulations (i.e., 60%). Additionally, ACQ enhanced the resistance of the composite materials to certain biotic stresses better than ZB. The CSF/HDPE composites treated with ACQ at the 3.0% level exhibited a superior performance against termites, white rot fungi, and brown rot fungi. ACQ treatment at the 1% level was optimal for inhibiting soft rot fungi. Furthermore, mold growth was not observed on ACQ-treated CSF/HDPE samples. The untreated CSF/HDPE composites were more susceptible to mold infections and decay than the untreated poplar/HDPE composites, likely because of an incomplete removal of the pith. The chemical features of the corn stalk may also have influenced these differences, but this possibility will need to be explored in future investigations. Furthermore, the CSF component of CSF/HDPE composites is highly susceptible to fungal attacks, with the soft rot fungus inducing the largest mass losses, followed by the white rot fungus, and then the brown rot fungus.
    Matched MeSH terms: Zinc
  3. Distribution of Heavy Metals in Core Marine Sediments of Coastal East Malaysia by Instrumental Neutron Activation Analysis and Inductively Coupled Plasma Spectroscopy
    Ashraf A, Saion E, Gharibshahi E, Yap CK, Kamari HM, Elias MS, et al.
    Appl Radiat Isot, 2018 Feb;132:222-231.
    PMID: 29183762 DOI: 10.1016/j.apradiso.2017.11.012
    Fifty-five core marine sediments from three locations at South China Sea and one location each at Sulu Sea and Sulawesi Sea of coastal East Malaysia were analyzed for heavy metals by instrumental neutron activation analysis and inductively coupled plasma mass spectroscopy. The enrichment factor and the modified degree of contamination were used to calculate the anthropogenic and pollution status of the elements in the samples. The enrichment factor of As, Cd, Cr, Cu, Ni, Pb, and Zn varied from 0.42-4.26, 0.50-2.34, 0.31-0.82, 0.20-0.61, 0.91-1.92, 0.23-1.52, and 0.90-1.28, respectively, with the modified degree of contamination values below 0.6. Comparative data showed that coastal East Malaysia has low levels of contamination.
    Matched MeSH terms: Zinc
  4. Fulltext Three dimensional metal/N-doped nanoplate carbon catalysts for oxygen reduction, the reason for using a layered nanoreactor
    Yeganeh Ghotbi M, Javanmard A, Soleimani H
    Sci Rep, 2018 02 21;8(1):3404.
    PMID: 29467510 DOI: 10.1038/s41598-018-21782-3
    A layered nanoreactor (zinc hydroxide gallate/nitrate nanohybrid) has been designed as a nano-vessel to confine the gallate/nitrate reaction inside zinc hydroxide layers for production of metal/nitrogen-doped carbon catalysts. Metals (Fe2+, Co2+ and Ni2+) doped and bare zinc hydroxide nitrates (ZHN) were synthesized as the α-phase hydroxide hosts. By an incomplete ion-exchange process, nitrate anions between the layers of the hosts were then partially replaced by the gallate anions to produce the layered nanoreactors. Under heat-treatment, the reaction between the remaining un-exchanged nitrate anions and the organic moiety inside the basal spacing of each nanohybrid plate resulted in obtaining highly porous 3D metal/nitrogen-doped carbon nanosheets. These catalysts were then used as extremely efficient electrocatalysts for catalyzing oxygen reduction reaction (ORR). This study is intended to show the way to get maximum electrocatalytic activity of the metal/N-doped carbon catalysts toward the ORR. This exceptionally high ORR performance originates from the increased available surface, the best pore size range and the uniform distribution of the active sites in the produced catalysts, all provided by the use of new idea of the layered nanoreactor.
    Matched MeSH terms: Zinc Compounds
  5. Fulltext How to face COVID-19: proposed treatments based on remdesivir and hydroxychloroquine in the presence of zinc sulfate. Docking/DFT/POM structural analysis
    Ben Hadda T, Berredjem M, Almalki FA, Rastija V, Jamalis J, Emran TB, et al.
    J Biomol Struct Dyn, 2022;40(19):9429-9442.
    PMID: 34033727 DOI: 10.1080/07391102.2021.1930161
    Remdesivir and hydroxychloroquine derivatives form two important classes of heterocyclic compounds. They are known for their anti-malarial biological activity. This research aims to analyze the physicochemical properties of remdesivir and hydroxychloroquine compounds by the computational approach. DFT, docking, and POM analyses also identify antiviral pharmacophore sites of both compounds. The antiviral activity of hydroxychloroquine compound's in the presence of zinc sulfate and azithromycin is evaluated through its capacity to coordinate transition metals (M = Cu, Ni, Zn, Co, Ru, Pt). The obtained bioinformatic results showed the potent antiviral/antibacterial activity of the prepared mixture (Hydroxychloroquine/Azithromycin/Zinc sulfate) for all the opportunistic Gram-positive, Gram-negative in the presence of coronavirus compared with the complexes Polypyridine-Ruthenium-di-aquo. The postulated zinc(II) complex of hydroxychloroquine derivatives are indeed an effective antibacterial and antiviral agent against coronavirus and should be extended to other pathogens. The combination of a pharmacophore site with a redox [Metal(OH2)2] moiety is of crucial role to fight against viruses and bacteria strains. [Formula: see text]Communicated by Ramaswamy H. Sarma.
    Matched MeSH terms: Zinc Sulfate
  6. Comparative analysis of an anthraquinone and chalcone derivatives-based virtual combinatorial library. A cheminformatics "proof-of-concept" study
    Moshawih S, Hadikhani P, Fatima A, Goh HP, Kifli N, Kotra V, et al.
    J Mol Graph Model, 2022 Dec;117:108307.
    PMID: 36096064 DOI: 10.1016/j.jmgm.2022.108307
    A Laplacian scoring algorithm for gene selection and the Gini coefficient to identify the genes whose expression varied least across a large set of samples were the state-of-the-art methods used here. These methods have not been trialed for their feasibility in cheminformatics. This was a maiden attempt to investigate a complete comparative analysis of an anthraquinone and chalcone derivatives-based virtual combinatorial library. This computational "proof-of-concept" study illustrated the combinatorial approach used to explain how the structure of the selected natural products (NPs) undergoes molecular diversity analysis. A virtual combinatorial library (1.6 M) based on 20 anthraquinones and 24 chalcones was enumerated. The resulting compounds were optimized to the near drug-likeness properties, and the physicochemical descriptors were calculated for all datasets including FDA, Non-FDA, and NPs from ZINC 15. UMAP and PCA were applied to compare and represent the chemical space coverage of each dataset. Subsequently, the Laplacian score and Gini coefficient were applied to delineate feature selection and selectivity among properties, respectively. Finally, we demonstrated the diversity between the datasets by employing Murcko's and the central scaffolds systems, calculating three fingerprint descriptors and analyzing their diversity by PCA and SOM. The optimized enumeration resulted in 1,610,268 compounds with NP-Likeness, and synthetic feasibility mean scores close to FDA, Non-FDA, and NPs datasets. The overlap between the chemical space of the 1.6 M database was more prominent than with the NPs dataset. A Laplacian score prioritized NP-likeness and hydrogen bond acceptor properties (1.0 and 0.923), respectively, while the Gini coefficient showed that all properties have selective effects on datasets (0.81-0.93). Scaffold and fingerprint diversity indicated that the descending order for the tested datasets was FDA, Non-FDA, NPs and 1.6 M. Virtual combinatorial libraries based on NPs can be considered as a source of the combinatorial compound with NP-likeness properties. Furthermore, measuring molecular diversity is supposed to be performed by different methods to allow for comparison and better judgment.
    Matched MeSH terms: Zinc
  7. Fulltext A sensitive and rapid determination of zinc ion (Zn2+) using electrochemical sensor based on f-MWCNTs/CS/PB/AuE in drinking water
    Ringgit G, Siddiquee S, Saallah S, Mohamad Lal MT
    Sci Rep, 2022 Nov 03;12(1):18582.
    PMID: 36329094 DOI: 10.1038/s41598-022-21926-6
    An electrochemical method for detecting the presence of zinc (Zn2+) ions in drinking water was developed using functionalized multi-walled carbon nanotubes (f-MWCNTs) and chitosan (CS). Numerous cylinder-shaped graphene molecules make up f-MWCNTs, which have a high mechanical and electrical conductivity. CS benefits from nanomaterials include biocompatibility, biodegradability, and low toxicity, which are excellent in capacity absorption of metal ions. Dangerous levels of metal ions such as zinc are currently present in drinking water as a result of human and natural activity. Zinc toxicity is associated with a variety of disorders, including Alzheimer's, Parkinson's, diabetes, and cancer. This study incorporated f-MWCNTs and CS with Prussian blue (PB) immobilised on a gold electrode (AuE). Several parameters, including as buffers, pH, scan rate, redox indicator, accumulation time, and volume, were optimised using the cyclic voltammetry (CV) method. According to the CV method, the optimal parameters were phosphate buffered saline (0.1 M, pH 2), 5 mM Prussian blue, 200 mVs-1 scan rate, and 5 s accumulation time. Under ideal circumstances, the differential pulse voltammetry (DPV) method was used to determine the Zn2+ ions concentration range of 0.2-7.0 ppm. The limit of detection (LOD) was 2.60 × 10-7 mol L-1 with a correlation coefficient of R2 = 0.9777. The recovery rate of the developed sensor (f-MWCNTs/CS/PB/AuE) ranged from 95.78 to 98.96%. The developed sensor showed a variety of advantages for detecting Zn2+ in drinking water, including a quick setup process, quick detection, high sensitivity, and mobility. This study developed the essential sensor for monitoring Zn2+ levels in drinking water in the future.
    Matched MeSH terms: Zinc
  8. QSAR modeling approaches to identify a novel ACE2 inhibitor that selectively bind with the C and N terminals of the ectodomain
    Jawarkar RD, Zaki MEA, Al-Hussain SA, Al-Mutairi AA, Samad A, Mukerjee N, et al.
    J Biomol Struct Dyn, 2024 Mar;42(5):2550-2569.
    PMID: 37144753 DOI: 10.1080/07391102.2023.2205948
    Due to the high rates of drug development failure and the massive expenses associated with drug discovery, repurposing existing drugs has become more popular. As a result, we have used QSAR modelling on a large and varied dataset of 657 compounds in an effort to discover both explicit and subtle structural features requisite for ACE2 inhibitory activity, with the goal of identifying novel hit molecules. The QSAR modelling yielded a statistically robust QSAR model with high predictivity (R2tr=0.84, R2ex=0.79), previously undisclosed features, and novel mechanistic interpretations. The developed QSAR model predicted the ACE2 inhibitory activity (PIC50) of 1615 ZINC FDA compounds. This led to the detection of a PIC50 of 8.604 M for the hit molecule (ZINC000027990463). The hit molecule's docking score is -9.67 kcal/mol (RMSD 1.4). The hit molecule revealed 25 interactions with the residue ASP40, which defines the N and C termini of the ectodomain of ACE2. The HIT molecule conducted more than thirty contacts with water molecules and exhibited polar interaction with the ARG522 residue coupled with the second chloride ion, which is 10.4 nm away from the zinc ion. Both molecular docking and QSAR produced comparable findings. Moreover, MD simulation and MMGBSA studies verified docking analysis. The MD simulation showed that the hit molecule-ACE2 receptor complex is stable for 400 ns, suggesting that repurposed hit molecule 3 is a viable ACE2 inhibitor.
    Matched MeSH terms: Zinc
  9. Correlation of endocrine disrupting chemicals with essential elements in biological samples of children (1-5 years) with different infectious diseases and impact on sustainable outdoor activities
    Li B, Wu G, Yang X, Li Z, Albasher G, Alsultan N, et al.
    Environ Res, 2023 Jul 15;229:115781.
    PMID: 37076035 DOI: 10.1016/j.envres.2023.115781
    Endocrine disrupting chemicals (EDCs) have been extensively explored due to their harmful effects on individual health and the environment by interfering with hormone activity and disrupting the endocrine system. However, their relationship with essential trace elements remains uncertain. This research aimed to investigate the possible correlation between essential trace elements and toxic metals, including cadmium (Cd), and lead (Pb) in children aged 1-5 years with various infectious diseases, including gastrointestinal disorders, typhoid fever, and pneumonia. The study was conducted on biological testing and specimen (scalp hair and whole blood) of diseased and non-diseased children of the same residential area and referent/control age-matched children from developed cities consuming domestically treated water. The media of biological samples were oxidized by an acid mixture before being analyzed by atomic absorption spectrophotometry. The accuracy and validity of the methodology were verified through accredited reference material from scalp hair and whole blood sample. The study results revealed that diseased children had lower mean values of essential trace elements (iron, copper, and zinc) in both scalp hair and blood, except for copper, which was found to be higher in blood samples of diseased children. This implies that the deficiency of essential residue and trace elements in children from rural areas who consume groundwater is linked to various infectious diseases. The study highlights the need for more human biomonitoring of EDCs to better comprehend their non-classical toxic properties and their concealed costs on human health. The findings suggest that exposure to EDCs could be associated with unfavorable health outcomes and emphasizes the need for future regulatory policies to minimize exposure and safeguard the health of current and forthcoming generations of children. Furthermore, the study highlights the implication of essential trace elements in maintaining good health and their potential correlation with toxic metals in the environment.
    Matched MeSH terms: Zinc
  10. Fulltext Zinc Supplementation and Ischemia Pre-conditioning in Renal Ischemia/Reperfusion Injury
    Mazaheri B, Emami F, Moslemi F, Talebi A, Nematbakhsh M
    Malays J Med Sci, 2019 Jul;26(4):39-46.
    PMID: 31496892 DOI: 10.21315/mjms2019.26.4.5
    Backgrounds: Renal ischemia/reperfusion (RIR) is a major cause of kidney dysfunction in clinic. The main objective of this study was to investigate the effect of pre-conditioning ischemia (IPC) and zinc (Zn) supplementation on renal RIR injury.

    Methods: A total of 63 unilateral nephrectomised male and female Wistar rats were divided into five groups. Group 1 (ShOPR): Rats as sham-operated group were subjected to surgical procedure without RIR. Group 2 (Isch): Rats underwent RIR (left kidney ischemia for 30 min followed by 48 h reperfusion). Group 3 (Zn+Isch): Rats were treated as group 2 but they received Zn sulphate (30 mg/kg) 1 h before induction of RIR. Group 4 (IPC+Isch): Rats were treated as group 2 but they underwent 1 min of ischemia followed by 3 min reperfusion as IPC, which was repeated for three times before induction of RIR. Group 5 (Zn+IPC+Isch): Rats were subjected to receive both Zn sulphate and IPC before induction of RIR. Urine samples were collected in the last 6 h of reperfusion, and finally biochemical and histological measurements were performed.

    Results: The serum level of creatinine (Cr), normalised kidney weight (KW) and kidney tissue damage score (KTDS) increased by RIR alone significantly (P < 0.05). These parameters were attenuated statistically by Zn supplementation (P < 0.05). However, IPC alone or co-treatment of Zn and IPC did not improve the biochemical and histological markers altered by RIR injury.

    Conclusion: Zn supplementation had a protective role against RIR while such protective effect was not observed by IPC alone or by co-treatment of Zn and IPC.

    Matched MeSH terms: Zinc
  11. Fulltext Hospital Universiti Sains Malaysia (HUSM): 25 Years Of Excellent Service
    Kamari Z
    Malays J Med Sci, 2009 Jan;16(1):16-24.
    PMID: 22589644 MyJurnal
    Our Hospital University Sains Malaysia (HUSM) was given the Cabinet approval to exist under the Ministry of Education on 23 November 1982. The Deputy Prime Minister during that period, Yang Berhormat Tun Musa Hitam announced this after the cabinet meeting was held together with the presence of the Yang Berhormat Ministers of Health; and Education, Director of the Public Works Department and the Implementation and Coordinating Unit, Prime Minister's Department. The first patients moved in on 14 March 1983 and the inauguration of HUSM was done on 26 August 1984 by the Duli Yang Maha Mulia Tuanku Ismail Petra Ibni Al-Marhum Sultan Yahya Petra, the Sultan of Kelantan Darul Naim. HUSM celebrated it's 25th anniversary at the Dewan Utama, USM Health Campus on the 15th December 2008 which was inaugurated by Yang Berhormat, Minister of Higher Education Dato' Seri Mohamed Khaled Nordin. USM's Vice Chancellor Professor Tan Sri Dato' Dzulkifli Abdul Razak, Chairman of the USM Board of Directors Tan Sri Dato' Haji Dr. Ani bin Arope, Health Campus Director Professor Dato' Dr. Mafauzy Mohamed, former Campus Director, Dato' Prof Mohd Roslani Abdul Majid, the current and previous Hospital Directors and Deputy Directors since 1983 were present. The achievements of HUSM since its establishment and its vision to fulfil the University's Accelerated Programme for Excellence (APEX) are elaborated.
    Matched MeSH terms: Zinc Oxide
  12. Tissue and Serum Trace Elements Concentration among Colorectal Patients: A Systematic Review of Case-Control Studies
    Nawi AM, Chin SF, Azhar Shah S, Jamal R
    Iran J Public Health, 2019 Apr;48(4):632-643.
    PMID: 31110973
    Background: Trace elements play a pivotal role in Colorectal Cancer (CRC) inhibition and development process. This systematic review provides the basic comparison of case-control studies focusing on concentration of trace elements between those with CRC and controls.

    Methods: The systematic review searched through two databases of Medline and Cochrane up to 24th June 2017. The search strategy focused on Population, Intervention, Comparison, and Outcomes (PICO). We searched the role of trace elements in cancer and focusing on case-control studies in CRC to obtain an insight into the differences in trace element concentrations between those with and without cancer.

    Results: The serum concentrations of Ca, Cu, Mg, Mn, Se, Si, and Zn were lower in CRC patients but for Co and S the levels were higher in CRC patients. The concentrations of Cd, Cr, Cu, Mg, Mn, Pb, and Zn were increased in patients with metastasis, but not in Se. As for colon tissue specimens, inconsistent levels were reported between studies, notably in Cu, Se, and Zn. No changes were reported for B and Ca levels. Most of the trace elements in the tissue specimens showed higher concentrations of Cr, Fe, K, Mg, P, Rb, S, and Si compared to Br.

    Conclusion: With the growing interest to understand the link between trace elements in carcinogenesis and the possible interactions, multi assessment analysis of a larger cohort of samples is necessary.

    Matched MeSH terms: Zinc
  13. Fulltext Enhanced ethanol gas sensing properties of SnO₂-core/ZnO-shell nanostructures
    Tharsika T, Haseeb AS, Akbar SA, Sabri MF, Hoong WY
    Sensors (Basel), 2014;14(8):14586-600.
    PMID: 25116903 DOI: 10.3390/s140814586
    An inexpensive single-step carbon-assisted thermal evaporation method for the growth of SnO2-core/ZnO-shell nanostructures is described, and the ethanol sensing properties are presented. The structure and phases of the grown nanostructures are investigated by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques. XRD analysis indicates that the core-shell nanostructures have good crystallinity. At a lower growth duration of 15 min, only SnO2 nanowires with a rectangular cross-section are observed, while the ZnO shell is observed when the growth time is increased to 30 min. Core-shell hierarchical nanostructures are present for a growth time exceeding 60 min. The growth mechanism for SnO2-core/ZnO-shell nanowires and hierarchical nanostructures are also discussed. The sensitivity of the synthesized SnO2-core/ZnO-shell nanostructures towards ethanol sensing is investigated. Results show that the SnO2-core/ZnO-shell nanostructures deposited at 90 min exhibit enhanced sensitivity to ethanol. The sensitivity of SnO2-core/ZnO-shell nanostructures towards 20 ppm ethanol gas at 400 °C is about ~5-times that of SnO2 nanowires. This improvement in ethanol gas response is attributed to high active sensing sites and the synergistic effect of the encapsulation of SnO2 by ZnO nanostructures.
    Matched MeSH terms: Zinc Oxide/chemistry*
  14. Fulltext Numerical investigation of heat transfer enhancement in a rectangular heated pipe for turbulent nanofluid
    Yarmand H, Gharehkhani S, Kazi SN, Sadeghinezhad E, Safaei MR
    ScientificWorldJournal, 2014;2014:369593.
    PMID: 25254236 DOI: 10.1155/2014/369593
    Thermal characteristics of turbulent nanofluid flow in a rectangular pipe have been investigated numerically. The continuity, momentum, and energy equations were solved by means of a finite volume method (FVM). The symmetrical rectangular channel is heated at the top and bottom at a constant heat flux while the sides walls are insulated. Four different types of nanoparticles Al2O3, ZnO, CuO, and SiO2 at different volume fractions of nanofluids in the range of 1% to 5% are considered in the present investigation. In this paper, effect of different Reynolds numbers in the range of 5000 < Re < 25000 on heat transfer characteristics of nanofluids flowing through the channel is investigated. The numerical results indicate that SiO2-water has the highest Nusselt number compared to other nanofluids while it has the lowest heat transfer coefficient due to low thermal conductivity. The Nusselt number increases with the increase of the Reynolds number and the volume fraction of nanoparticles. The results of simulation show a good agreement with the existing experimental correlations.
    Matched MeSH terms: Zinc Oxide/chemistry
  15. Fulltext Improved photodynamic efficacy of Zn(II) phthalocyanines via glycerol substitution
    Chin Y, Lim SH, Zorlu Y, Ahsen V, Kiew LV, Chung LY, et al.
    PLoS One, 2014;9(5):e97894.
    PMID: 24840576 DOI: 10.1371/journal.pone.0097894
    Phthalocyanines are excellent photosensitizers for photodynamic therapy as they have strong absorbance in the near infra-red region which is most relevant for in vivo activation in deeper tissular regions. However, most phthalocyanines present two major challenges, ie, a strong tendency to aggregate and low water-solubility, limiting their effective usage clinically. In the present study, we evaluated the potential enhancement capability of glycerol substitution on the photodynamic properties of zinc (II) phthalocyanines (ZnPc). Three glycerol substituted ZnPc, 1-3, (tetra peripherally, tetra non-peripherally and mono iodinated tri non-peripherally respectively) were evaluated in terms of their spectroscopic properties, rate of singlet oxygen generation, partition coefficient (log P), intracellular uptake, photo-induced cytotoxicity and vascular occlusion efficiency. Tetrasulfonated ZnPc (ZnPcS4) was included as a reference compound. Here, we showed that 1-3 exhibited 10-100 nm red-shifted absorption peaks with higher molar absorptivity, and at least two-fold greater singlet oxygen generation rates compared to ZnPcS4. Meanwhile, phthalocyanines 1 and 2 showed more hydrophilic log P values than 3 consistent with the number of glycerol attachments but 3 was most readily taken up by cells compared to the rest. Both phthalocyanines 2 and 3 exhibited potent phototoxicity against MCF-7, HCT-116 and HSC-2 cancer cell-lines with IC50 ranging 2.8-3.2 µM and 0.04-0.06 µM respectively, while 1 and ZnPcS4 (up to 100 µM) failed to yield determinable IC50 values. In terms of vascular occlusion efficiency, phthalocyanine 3 showed better effects than 2 by causing total occlusion of vessels with diameter <70 µm of the chorioallantoic membrane. Meanwhile, no detectable vascular occlusion was observed for ZnPcS4 with treatment under similar experimental conditions. These findings provide evidence that glycerol substitution, in particular in structures 2 and 3, is able to improve the photodynamic properties of ZnPc.
    Matched MeSH terms: Zinc/chemistry*
  16. Fulltext A novel DNA nanosensor based on CdSe/ZnS quantum dots and synthesized Fe3O4 magnetic nanoparticles
    Hushiarian R, Yusof NA, Abdullah AH, Ahmad SA, Dutse SW
    Molecules, 2014 Apr 09;19(4):4355-68.
    PMID: 24722589 DOI: 10.3390/molecules19044355
    Although nanoparticle-enhanced biosensors have been extensively researched, few studies have systematically characterized the roles of nanoparticles in enhancing biosensor functionality. This paper describes a successful new method in which DNA binds directly to iron oxide nanoparticles for use in an optical biosensor. A wide variety of nanoparticles with different properties have found broad application in biosensors because their small physical size presents unique chemical, physical, and electronic properties that are different from those of bulk materials. Of all nanoparticles, magnetic nanoparticles are proving to be a versatile tool, an excellent case in point being in DNA bioassays, where magnetic nanoparticles are often used for optimization of the hybridization and separation of target DNA. A critical step in the successful construction of a DNA biosensor is the efficient attachment of biomolecules to the surface of magnetic nanoparticles. To date, most methods of synthesizing these nanoparticles have led to the formation of hydrophobic particles that require additional surface modifications. As a result, the surface to volume ratio decreases and nonspecific bindings may occur so that the sensitivity and efficiency of the device deteriorates. A new method of large-scale synthesis of iron oxide (Fe3O4) nanoparticles which results in the magnetite particles being in aqueous phase, was employed in this study. Small modifications were applied to design an optical DNA nanosensor based on sandwich hybridization. Characterization of the synthesized particles was carried out using a variety of techniques and CdSe/ZnS core-shell quantum dots were used as the reporter markers in a spectrofluorophotometer. We showed conclusively that DNA binds to the surface of ironoxide nanoparticles without further surface modifications and that these magnetic nanoparticles can be efficiently utilized as biomolecule carriers in biosensing devices.
    Matched MeSH terms: Zinc Compounds/chemistry*
  17. Fulltext An inhibitive enzyme assay to detect mercury and zinc using protease from Coriandrum sativum
    Baskaran G, Masdor NA, Syed MA, Shukor MY
    ScientificWorldJournal, 2013;2013:678356.
    PMID: 24194687 DOI: 10.1155/2013/678356
    Heavy metals pollution has become a great threat to the world. Since instrumental methods are expensive and need skilled technician, a simple and fast method is needed to determine the presence of heavy metals in the environment. In this study, an inhibitive enzyme assay for heavy metals has been developed using crude proteases from Coriandrum sativum. In this assay, casein was used as a substrate and Coomassie dye was used to denote the completion of casein hydrolysis. In the absence of inhibitors, casein was hydrolysed and the solution became brown, while in the presence of metal ions such as Hg²⁺ and Zn²⁺, the hydrolysis of casein was inhibited and the solution remained blue. Both Hg²⁺ and Zn²⁺ exhibited one-phase binding curve with IC₅₀ values of 3.217 mg/L and 0.727 mg/L, respectively. The limits of detection (LOD) and limits of quantitation (LOQ) for Hg were 0.241 and 0.802 mg/L, respectively, while the LOD and LOQ for Zn were 0.228 and 0.761 mg/L, respectively. The enzyme exhibited broad pH ranges for activity. The crude proteases extracted from Coriandrum sativum showed good potential for the development of a rapid, sensitive, and economic inhibitive assay for the biomonitoring of Hg²⁺ and Zn²⁺ in the aquatic environments.
    Matched MeSH terms: Zinc/analysis*
  18. Surface enhanced Raman scattering and plasmon enhanced fluorescence in zinc-tellurite glass
    Amjad RJ, Sahar MR, Dousti MR, Ghoshal SK, Jamaludin MN
    Opt Express, 2013 Jun 17;21(12):14282-90.
    PMID: 23787617 DOI: 10.1364/OE.21.014282
    We report significant enhancements in Er(3+) luminescence as well as in Raman intensity in silver nanoparticles embedded zinc-tellurite glass. Surface enhanced Raman scattering effect is highlighted for the first time in tellurite glass containing silver NPs resulting in an enhanced Raman signal (~10 times). SAED manifest the growth of Ag(0) nanoparticles along the (111) and (200) crystallographic planes having average diameter in the range 14-36 nm. Surface plasmon resonance bands are observed in the range 484-551 nm. Furthermore, four prominent photoluminescence bands undergo significant enhancements up to 3 times. The enhancement is majorly attributed to the local field effect of silver NPs.
    Matched MeSH terms: Zinc/chemistry*
  19. Fulltext Synthesis, antibacterial and thermal studies of cellulose nanocrystal stabilized ZnO-Ag heterostructure nanoparticles
    Azizi S, Ahmad MB, Hussein MZ, Ibrahim NA
    Molecules, 2013 May 28;18(6):6269-80.
    PMID: 23760028 DOI: 10.3390/molecules18066269
    Synthesis of ZnO-Ag heterostructure nanoparticles was carried out by a precipitation method with cellulose nanocrystals (CNCs) as a stabilizer for antimicrobial and thermal studies. ZnO-Ag nanoparticles were obtained from various weight percentages of added AgNO₃ relative to Zn precursors for evaluating the best composition with enhanced functional properties. The ZnO-Ag/CNCs samples were characterized systematically by TEM, XRD, UV, TGA and DTG. From the TEM studies we observed that ZnO-Ag heterostructure nanoparticles have spherical shapes with size diameters in a 9-35 nm range. The antibacterial activities of samples were assessed against the bacterial species Salmonella choleraesuis and Staphylococcus aureus. The CNC-stabilized ZnO-Ag exhibited greater bactericidal activity compared to cellulose-free ZnO-Ag heterostructure nanoparticles of the same particle size. The incorporation of ZnO-Ag hetreostructure nanoparticles significantly increased the thermal stability of cellulose nanocrystals.
    Matched MeSH terms: Zinc Oxide/chemistry*
  20. Fulltext Photocatalytic degradation of p-cresol by zinc oxide under UV irradiation
    Abdollahi Y, Abdullah AH, Zainal Z, Yusof NA
    Int J Mol Sci, 2012;13(1):302-15.
    PMID: 22312253 DOI: 10.3390/ijms13010302
    Photocatalytic degradation of p-cresol was carried out using ZnO under UV irradiation. The amount of photocatalyst, concentration of p-cresol and pH were studied as variables. The residual concentration and mineralization of p-cresol was monitored using a UV-visible spectrophotometer and total organic carbon (TOC) analyzer, respectively. The intermediates were detected by ultra high pressure liquid chromatography (UPLC). The highest photodegradation of p-cresol was observed at 2.5 g/L of ZnO and 100 ppm of p-cresol. P-cresol photocatalytic degradation was favorable in the pH range of 6-9. The detected intermediates were 4-hydroxy-benzaldehyde and 4-methyl-1,2-benzodiol. TOC studies show that 93% of total organic carbon was removed from solution during irradiation time. Reusability shows no significant reduction in photocatalytic performance in photodegrading p-cresol.
    Matched MeSH terms: Zinc Oxide/chemistry*
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