MyMedR

Displaying publications 381 - 400 of 624 in total

Abstract:

Sort:

A bio-mimetic zinc/tau protein as an artificial catalase

Asadollahi K, Jasemi NS, Riazi GH, Katuli FH, Yazdani F, Sartipnia N, et al.

Int J Biol Macromol, 2016 Nov;92:1307-1312.
PMID: 26905468 DOI: 10.1016/j.ijbiomac.2016.02.045

In this study, the catalase-like activity of monomeric tau protein was reported in the presence of of zinc (Zn(II)) ions at low pH value. Monomeric tau protein contains two SH groups that are a target of disulfide bond formation. However these SH groups are able to interact with Zn(II) ion at pH 7.2 which creates a thiol bond as a mimetic model of chloroperoxidase active site which performs catalase like activity at low pH. Zn(II)/tau protein complex decomposed H2O2 with a high rate (Vm) as well as an efficient turn oven number (kcat) at pH 3. This remarkable catalase like activity is may be attributed to the conformational reorientation of protein at low pH. Circular dichroism (CD) studies did not demonstrate any secondary structural changes of tau protein after addition of Zn(II) ions at pH 7.2. In addition, tau protein shows identical CD bands at pH 7.2 and 3. Moreover, fluorescence quenching of tau by Zn(II) at pH 7.2 was initiated by complex formation rather than by dynamic collision. A significant red shift (6nm) was observed in the emission maximum of the fluorescence spectra when the protein was dissolved at pH 3 compared to pH 7.2. This conformational change can provide information regarding the rearrangements of the protein structure and exposure of Cys-Zn(II) group to the solvent which induces easy access of active site to H2O2 molecules and corresponding enhanced catalytic activity of Zn(II)/tau protein complex. This study introduces tau protein as a bio-inspired high performing scaffold for transition metal encapsulation and introducing an engineered apoprotein-induced biomimetic enzyme.

Matched MeSH terms: Zinc/chemistry*
Characterization of spatial and temporal variability in hydrochemistry of Johor Straits, Malaysia

Abdullah P, Abdullah SMS, Jaafar O, Mahmud M, Khalik WMAWM

Mar Pollut Bull, 2015 Dec 15;101(1):378-385.
PMID: 26476861 DOI: 10.1016/j.marpolbul.2015.10.014

Characterization of hydrochemistry changes in Johor Straits within 5 years of monitoring works was successfully carried out. Water quality data sets (27 stations and 19 parameters) collected in this area were interpreted subject to multivariate statistical analysis. Cluster analysis grouped all the stations into four clusters ((Dlink/Dmax) × 100<90) and two clusters ((Dlink/Dmax) × 100<80) for site and period similarities. Principal component analysis rendered six significant components (eigenvalue>1) that explained 82.6% of the total variance of the data set. Classification matrix of discriminant analysis assigned 88.9-92.6% and 83.3-100% correctness in spatial and temporal variability, respectively. Times series analysis then confirmed that only four parameters were not significant over time change. Therefore, it is imperative that the environmental impact of reclamation and dredging works, municipal or industrial discharge, marine aquaculture and shipping activities in this area be effectively controlled and managed.

Matched MeSH terms: Zinc/analysis
Dinuclear Gold(I) Pyrrolidinedithiocarbamato Complex: Cytotoxic and Antimigratory Activities on Cancer Cells and the Use of Metal-Organic Framework

Sun RW, Zhang M, Li D, Zhang ZF, Cai H, Li M, et al.

Chemistry, 2015 Dec 14;21(51):18534-8.
PMID: 26459298 DOI: 10.1002/chem.201503656

A dinuclear gold(I) pyrrolidinedithiocarbamato complex (1) with a bidentate carbene ligand has been constructed and shows potent in vitro cytotoxic activities towards cisplatin-resistant ovarian cancer cells A2780cis. Its rigid scaffold enables a zinc(II)-based metal-organic framework (Zn-MOF) to be used as a carrier in facilitating the uptake and release of 1 in solutions. Instead of using a conventional dialysis approach for the drug-release testing, in this study, a set of transwell assay-based experiments have been designed and employed to examine the cytotoxic and antimigratory activities of 1@Zn-MOF towards A2780cis.

Matched MeSH terms: Zinc/chemistry*
Processing and properties optimisation of carbon nanofibre-reinforced magnesium composites for biomedical applications

Tuminoh H, Hermawan H, Ramlee MH

J Mech Behav Biomed Mater, 2022 Nov;135:105457.
PMID: 36116340 DOI: 10.1016/j.jmbbm.2022.105457

In the last decade, magnesium alloys have been considered as absorbable metals for biomedical applications, while some have reached their clinical use as temporary bone implants. However, their widespread use is still limited by its strength and degradability. One way of improvement can be done by reinforcing magnesium alloys with carbon nanofibres to form composites. This work aims at developing carbon nanofibre-reinforced magnesium-zinc (Mg-Zn/CNF) composites with optimum strength and degradability while ensuring their biocompatibility. A response surface method was used to determine their optimum process parameters (composition, compaction pressure, and sintering temperature), and analyse the resulting properties (elastic modulus, hardness, weight loss, and cytocompatibility). Results showed that the optimal parameters were reached at 1.8% of CNF, 425 MPa of compaction pressure, and 500 °C of sintering temperature, whereby it gave an elastic modulus of 5 GPa, hardness of 60 Hv, and a weight loss of 51% after three days immersion in PBS. The composites exhibited a hydrophobic surface that controlled the liberation of Mg2+ and Zn2+ ions, leading to more than 70% osteoblast cells viability up to seven days of incubation. This study can also serve as a starting point for future researchers interested in finding methods to fabricate Mg-Zn/CNF composites with high mechanical characteristics, corrosion resistance, and biocompatibility.

Matched MeSH terms: Zinc/chemistry
Fulltext The Effect of Intragastric Gavage of High Dose Green Tea Extract on Serum Status of Magnesium, Calcium, and Zinc

Khaleel AK, Shaari RB, Nawi MAA, Al-Yassiri AMH

Asian Pac J Cancer Prev, 2022 Sep 01;23(9):3195-3199.
PMID: 36172684 DOI: 10.31557/APJCP.2022.23.9.3195

OBJECTIVE: Green tea (GT) contains polyphenolic flavonoids, different minerals like magnesium, calcium, and zinc, vitamins, amino acids, carbohydrates, proteins, and others. It has a different health benefit. The aim of the present study was to investigate the effect of intragastric gavage of a high dose GT extract on serum biochemical analysis of magnesium, calcium, and zincin juvenile Wistar albino rats.
METHODS: Twelve rats were used in the study and divided in to two equal groups. All the animals in the control group were intragastically gavaged by distilled water and continues for ten days, from day 24 to day 34 of age, while the animals in the study group were intragastically gavaged by GT extract (300mg/kg/day) which continues also for ten days from day 24 to day 34 of age. On day 34 of age, and two hours after the last dose, the rats were anaesthetized and blood collection by cardiac puncture was taken.
RESULTS: The results showed that the intragastric gavage of a high dose of GT extract caused a non-significant increase in serum magnesium, and calcium levels (p>0.05), but a significant increase in zinc serum level was seen(p< 0.05).
CONCLUSION: GT can cause a significant increase in zinc serum level, and this may explain the significant role of GT in the response to different oxidative stress. It is recommended to measure the Zn serum level in rats after a period longer than two hrs from the time of the last dose of intragastric gavage of GT extract.

Matched MeSH terms: Zinc*
Blended Nephelium lappaceum and Durio zibethinus wastes for activated carbon production via microwave-ZnCl2 activation: optimization for methylene blue dye removal

Jawad AH, Hapiz A, Wu R, Abdulhameed AS, ALOthman ZA

Int J Phytoremediation, 2024;26(10):1655-1666.
PMID: 38711172 DOI: 10.1080/15226514.2024.2344178

Herein, this work targets to employ the blended fruit wastes including rambutan (Nephelium lappaceum) peel and durian (Durio zibethinus) seed as a promising precursor to produce activated carbon (RPDSAC). The generation of RPDSAC was accomplished through a rapid and practical procedure (microwave-ZnCl2 activation). To evaluate the adsorptive capabilities of RPDSAC, its efficacy in eliminating methylene blue (MB), a simulated cationic dye, was measured. The Box-Behnken design (BBD) was utilized to optimize the crucial adsorption parameters, namely A: RPDSAC dose (0.02-01 g/100 mL), B: pH (4-10), and C: time (2-6 min). The BBD design determined that the highest level of MB removal (79.4%) was achieved with the condition dosage of RPDSAC at 0.1 g/100 mL, contact time (6 min), and pH (10). The adsorption isotherm data is consistent with the Freundlich concept, and the pseudo-second-order versions adequately describe the kinetic data. The monolayer adsorption capacity (qmax) of RPDSAC reached 120.4 mg/g at 25 °C. Various adsorption mechanisms are involved in the adsorption of MB dye onto the surface of RPDSAC, including π-π stacking, H-bonding, pore filling, and electrostatic forces. This study exhibits the potential of the RPDSAC as an adsorbent for removal of toxic cationic dye (MB) from contaminated wastewater.

Matched MeSH terms: Zinc Compounds*
Green synthesis of anisotropic zinc oxide nanoparticles with antibacterial and cytofriendly properties

Saravanan M, Gopinath V, Chaurasia MK, Syed A, Ameen F, Purushothaman N

Microb Pathog, 2018 Feb;115:57-63.
PMID: 29248514 DOI: 10.1016/j.micpath.2017.12.039

Zinc oxide nanoparticles (ZnONPs) exhibit abundant biomedical applications. Anisotropic ZnONPs with a defined shape and size were synthesized using Bacillus megaterium (NCIM 2326) cell free extract as a bio-reductant. The study investigated the multidimensional effect of ZnONPs on Helicobacter pylori strains and assessed its biosafety in normal human mesenchymal stem cells (hMSc). The highly stable ZnONPs were produced using B. megaterium and Zinc nitrate as a precursor. The phase of ZnONPs formation and structural characterization were performed by UV- visible (UV-Vis), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and Field Emission Scanning electron microscopy (FESEM) analysis. Furthermore, the ZnONPs exhibited higher biocompatibility against human mesenchymal stem cells (hMSC) and proved to be potentially safe in mammalian cells. Corroborating the current investigation, we described the anti-H. Pylori dosage of ZnONPs was safe to hMSC and could efficiently use as nano-antibiotic.

Matched MeSH terms: Zinc Oxide/metabolism; Zinc Oxide/pharmacology*
Fulltext Down-top nanofabrication of binary (CdO)x (ZnO)1-x nanoparticles and their antibacterial activity

Al-Hada NM, Mohamed Kamari H, Abdullah CAC, Saion E, Shaari AH, Talib ZA, et al.

Int J Nanomedicine, 2017;12:8309-8323.
PMID: 29200844 DOI: 10.2147/IJN.S150405

In the present study, binary oxide (cadmium oxide [CdO])x (zinc oxide [ZnO])1-x nanoparticles (NPs) at different concentrations of precursor in calcination temperature were prepared using thermal treatment technique. Cadmium and zinc nitrates (source of cadmium and zinc) with polyvinylpyrrolidone (capping agent) have been used to prepare (CdO)x (ZnO)1-x NPs samples. The sample was characterized by X-ray diffraction (XRD), scanning electron microscopy, energy-dispersive X-ray (EDX), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. XRD patterns analysis revealed that NPs were formed after calcination, which showed a cubic and hexagonal crystalline structure of (CdO)x (ZnO)1-x NPs. The phase analysis using EDX spectroscopy and FTIR spectroscopy confirmed the presence of Cd and Zn as the original compounds of prepared (CdO)x (ZnO)1-x NP samples. The average particle size of the samples increased from 14 to 33 nm as the concentration of precursor increased from x=0.20 to x=0.80, as observed by TEM results. The surface composition and valance state of the prepared product NPs were determined by X-ray photoelectron spectroscopy (XPS) analyses. Diffuse UV-visible reflectance spectra were used to determine the optical band gap through the Kubelka-Munk equation; the energy band gap was found to decrease for CdO from 2.92 to 2.82 eV and for ZnO from 3.22 to 3.11 eV with increasing x value. Additionally, photoluminescence (PL) spectra revealed that the intensity in PL increased with an increase in particle size. In addition, the antibacterial activity of binary oxide NP was carried out in vitro against Escherichia coli ATCC 25922 Gram (-ve), Salmonella choleraesuis ATCC 10708, and Bacillus subtilis UPMC 1175 Gram (+ve). This study indicated that the zone of inhibition of 21 mm has good antibacterial activity toward the Gram-positive B. subtilis UPMC 1175.

Matched MeSH terms: Zinc Oxide/pharmacology; Zinc Oxide/chemistry*
A facile ultrasonic-aided biosynthesis of ZnO nanoparticles using Vaccinium arctostaphylos L. leaf extract and its antidiabetic, antibacterial, and oxidative activity evaluation

Bayrami A, Alioghli S, Rahim Pouran S, Habibi-Yangjeh A, Khataee A, Ramesh S

Ultrason Sonochem, 2019 Jul;55:57-66.
PMID: 31084791 DOI: 10.1016/j.ultsonch.2019.03.010

The synthesis of nanoparticles often result in the generation of harmful chemical pollutants. As such, many researchers have focused on developing green processes, which include the biosynthesis. In this research, ZnO nanoparticles were prepared using the leaf extract of whortleberry (Vaccinium arctostaphylos L.) via a simple ultrasonic-assisted method. The morphology, crystal size and structure, surface, thermal, and optical properties of the bio-mediated ZnO sample (ZnOext) were analyzed and compared with that produced without incorporating the extract (ZnOchem). The ZnO samples were evaluated for their antidiabetic, antibacterial, as well as their sono- and photo-catalytic performances. Initially, the samples were intraperitoneal injected to alloxan-diabetic rats to examine their treatment efficiency in terms of effects on fasting blood glucose, insulin, cholesterol, high-density lipoprotein, and total triglyceride levels. The ZnOext showed significantly higher efficiency for improving the health status of alloxan-diabetic rats in contrast with other tested treatments, vis. ZnOchem, insulin, and only leaf extract. In addition, both the ZnO samples were assessed against gram-negative and gram-positive bacteria and through sono- and photo-catalytic processes for removing rhodamine B, respectively. The results of this study indicated that not only the ZnOext sample was pollution free, it also exhibited higher potentials for treating diabetic rats, bacterial decontamination, and also oxidative removal of organic compounds under the influences of ultrasound and UV irradiations when compared with ZnOchem sample.

Matched MeSH terms: Zinc Oxide/pharmacology*; Zinc Oxide/chemistry*
Fulltext Compositions and antimicrobial properties of binary ZnO-CuO nanocomposites encapsulated calcium and carbon from Calotropis gigantea targeted for skin pathogens

Govindasamy GA, Mydin RBSMN, Sreekantan S, Harun NH

Sci Rep, 2021 01 08;11(1):99.
PMID: 33420110 DOI: 10.1038/s41598-020-79547-w

Calotropis gigantea (C. gigantea) extract with an ecofriendly nanotechnology approach could provide promising antimicrobial activity against skin pathogens. This study investigates the antimicrobial capability of green synthesized binary ZnO-CuO nanocomposites from C. gigantea against non-MDR (Staphylococcus aureus and Escherichia coli) and MDR (Klebsiella pneumoniae, Pseudomonas aeruginosa and methicillin-resistant S. aureus) skin pathogens. Scanning electron microscopy and transmission electron microscopy revealed the size and shape of B3Z1C sample. Results of X-ray powder diffraction, energy-dispersive spectroscopy, FTIR and UV-Vis spectroscopy analyses confirmed the presence of mixed nanoparticles (i.e., zinc oxide, copper oxide, carbon and calcium) and the stabilising phytochemical agents of plant (i.e., phenol and carbonyl). Antimicrobial results showed that carbon and calcium decorated binary ZnO-CuO nanocomposites with compositions of 75 wt% of ZnO and 25 wt% CuO (B3Z1C) was a strong bactericidal agent with the MBC/MIC ratio of ≤ 4 and ≤ 2 for non-MDR and MDR pathogens, respectively. A significant non-MDR zone of inhibitions were observed for BZC by Kirby-Bauer disc-diffusion test. Further time-kill observation revealed significant fourfold reduction in non-MDR pathogen viable count after 12 h study period. Further molecular studies are needed to explain the biocidal mechanism underlying B3Z1C potential.

Matched MeSH terms: Zinc Oxide/pharmacology*; Zinc Oxide/chemistry*
Biosorption of copper and zinc by immobilised and free algal biomass, and the effects of metal biosorption on the growth and cellular structure of Chlorella sp. and Chlamydomonas sp. isolated from rivers in Penang, Malaysia

Maznah WO, Al-Fawwaz AT, Surif M

J Environ Sci (China), 2012;24(8):1386-93.
PMID: 23513679

In this study, the biosorption of copper and zinc ions by Chlorella sp. and Chlamydomonas sp. isolated from local environments in Malaysia was investigated in a batch system and by microscopic analyses. Under optimal biosorption conditions, the biosorption capacity of Chlorella sp. for copper and zinc ions was 33.4 and 28.5 mg/g, respectively, after 6 hr of biosorption in an immobilised system. Batch experiments showed that the biosorption capacity of algal biomass immobilised in the form of sodium alginate beads was higher than that of the free biomass. Scanning electron microscopy and energy-dispersive X-ray spectroscopy analyses revealed that copper and zinc were mainly sorbed at the cell surface during biosorption. Exposure to 5 mg/L of copper and zinc affected both the chlorophyll content and cell count of the algal cells after the first 12 hr of contact time.

Matched MeSH terms: Zinc/isolation & purification*; Zinc/toxicity
Comparative toxicity of eight metals on freshwater fish

Shuhaimi-Othman M, Yakub N, Ramle NA, Abas A

Toxicol Ind Health, 2015 Sep;31(9):773-82.
PMID: 23302712 DOI: 10.1177/0748233712472519

Two freshwater fish, Rasbora sumatrana (Cyprinidae) and Poecilia reticulata (guppy; Poeciliidae), were exposed to a range of eight heavy metals (copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn)) at varied concentrations for 96 h in the laboratory. Mortality was assessed and median lethal concentrations (LC50) were calculated. It was observed that the LC50 values increased with a decrease in mean exposure times, for all metals and for both fish types. The 96-h LC50 values for Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 0.006, 0.10, 0.46, 0.63, 0.83, 1.71, 1.53, and 5.71 mg/L for R. sumatrana and 0.038, 0.17, 1.06, 1.99, 15.62, 1.46, 6.76, and 23.91 mg/L for P. reticulata, respectively. The metal toxicity trend for R. sumatrana and P. reticulata from most to least toxic was Cu > Cd > Zn > Pb > Ni > Al > Fe > Mn and Cu > Cd > Zn > Fe > Pb > Al > Ni > Mn, respectively. Results indicated that Cu was the most toxic metal on both fish, and R. sumatrana was more sensitive than P. reticulata to all the eight metals.

Matched MeSH terms: Zinc/analysis; Zinc/toxicity
Comparison of unmodified and modified BCR sequential extraction schemes for the fractionation of heavy metals in shrimp aquaculture sludge from Selangor, Malaysia

Nemati K, Abu Bakar NK, Abas MR, Sobhanzadeh E, Low KH

Environ Monit Assess, 2011 May;176(1-4):313-20.
PMID: 20632089 DOI: 10.1007/s10661-010-1584-3

A study was carried out to investigate the fractionation of Cd, Cr, Cu, Fe, Mn, Pb, and Zn in shrimp aquaculture sludge from Selangor, Malaysia, using original (unmodified) and modified four-steps BCR (European Community Bureau of Reference, now known as the Standards Measurements and Testing Program) sequential extraction scheme. Step 2 of the unmodified BCR procedure (subsequently called Method A) involves treatment with 0.1 M hydroxylammonium chloride at pH 2, whereas 0.5 M hydroxylammonium chloride at pH 1.5 was used in the modified BCR procedure (subsequently called Method B). Metal analyses were carried out by flame atomic absorption spectrometry. A pseudo-total aqua-regia digest of BCR CRM 701 has also been undertaken for quality assurance purposes. The recovery of Method A for all metals studied ranges from 96.14% to 105.26%, while the recovery for Method B ranges from 95.94% to 122.40%. Our results reveal that Method A underestimated the proportion of metals bound to the easily reducible fraction except for copper. Therefore, the potential mobility of these elements is higher than others. Thus, to use this sludge as a fertilizer we have to first find a remediation for reduction of heavy metal contamination.

Matched MeSH terms: Zinc/isolation & purification; Zinc/chemistry
Zinc (II) complex with a cationic Schiff base ligand: synthesis, characterization, and biological studies

Lee SK, Tan KW, Ng SW, Ooi KK, Ang KP, Abdah MA

Spectrochim Acta A Mol Biomol Spectrosc, 2014;121:101-8.
PMID: 24231745 DOI: 10.1016/j.saa.2013.10.084

A cationic Schiff base ligand, TSB (L) and its Zn (II) complex (1) were synthesized and characterized by using CHN, (1)H-NMR, FT-IR, UV, LC-MS, and X-ray methods. Their ability to inhibit topoisomerase I, DNA cleavage activities, and cytotoxicity were studied. X-ray diffraction study shows that the mononuclear complex 1 is four coordinated with distorted tetrahedral geometry. The singly deprotonated Schiff base ligand L acts as a bidentate ON-donor ligand. Complexation of L increases the inhibitory strength on topoisomerase I activity. Complex 1 could fully inhibit topoisomerase I activity at 250 μM, while L did not show any inhibitory effect on topoisomerase I activity. In addition, L and complex 1 could cleave pBR322 DNA in a concentration and time dependent profile. Surprisingly, L has better DNA cleavage activity than complex 1. The cleavage of DNA by complex 1 is altered in the presence of hydrogen peroxide. Furthermore, L and complex 1 are mildly cytotoxic towards human ovarian cancer A2780 and hepatocellular carcinoma HepG2.

Matched MeSH terms: Zinc/pharmacology*; Zinc/toxicity
Fulltext Cytotoxicity of nickel zinc ferrite nanoparticles on cancer cells of epithelial origin

Al-Qubaisi MS, Rasedee A, Flaifel MH, Ahmad SH, Hussein-Al-Ali S, Hussein MZ, et al.

Int J Nanomedicine, 2013;8:2497-508.
PMID: 23885175 DOI: 10.2147/IJN.S42367

In this study, in vitro cytotoxicity of nickel zinc (NiZn) ferrite nanoparticles against human colon cancer HT29, breast cancer MCF7, and liver cancer HepG2 cells was examined. The morphology, homogeneity, and elemental composition of NiZn ferrite nanoparticles were investigated by scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy, respectively. The exposure of cancer cells to NiZn ferrite nanoparticles (15.6-1,000 μg/mL; 72 hours) has resulted in a dose-dependent inhibition of cell growth determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The quantification of caspase-3 and -9 activities and DNA fragmentation to assess the cell death pathway of the treated cells showed that both were stimulated when exposed to NiZn ferrite nanoparticles. Light microscopy examination of the cells exposed to NiZn ferrite nanoparticles demonstrated significant changes in cellular morphology. The HepG2 cells were most prone to apoptosis among the three cells lines examined, as the result of treatment with NiZn nanoparticles. In conclusion, NiZn ferrite nanoparticles are suggested to have potential cytotoxicity against cancer cells.

Matched MeSH terms: Zinc Compounds/pharmacology*; Zinc Compounds/chemistry
Possible role of metal ionophore against zinc induced cognitive dysfunction in D-galactose senescent mice

Bharti K, Majeed AB, Prakash A

Biometals, 2016 Jun;29(3):399-409.
PMID: 26923568 DOI: 10.1007/s10534-016-9922-8

Metal ionophores are considered as potential anti-dementia agents, and some are currently undergoing clinical trials. Many metals are known to accumulate and distribute abnormally in the aging brain. Alterations in zinc metal homeostasis in the glutaminergic synapse could contribute to ageing and the pathophysiology of Alzheimer's disease (AD). The present study was designed to investigate the effect of metal ionophores on long term administration of zinc in D-galactose induced senescent mice. The ageing model was established by combined administration of zinc and D-galactose to mice for 6 weeks. A novel metal ionophore, PBT-2 was given daily to zinc-induced d-galactose senescent mice. The cognitive behaviour of mice was monitored using the Morris Water Maze. The anti-oxidant status and amyloidogenic activity in the ageing mouse was measured by determining mito-oxidative parameters and deposition of amyloid β (Aβ) in the brain. Systemic administration of both zinc and D-galactose significantly produced memory deficits, mito-oxidative damage, heightened acetylcholinesterase enzymatic activity and deposition of amyloid-β. Treatment with PBT-2 significantly improved behavioural deficits, biochemical profiles, cellular damage, and curbed the deposition of APP in zinc-induced senescent mice. These findings suggest that PBT-2, acting as a metal protein attenuating compound, may be helpful in the prevention of AD or alleviation of ageing.

Matched MeSH terms: Zinc Sulfate/administration & dosage; Zinc Sulfate/pharmacology*
Titanium addition influences antibacterial activity of bioactive glass coatings on metallic implants

Rodriguez O, Stone W, Schemitsch EH, Zalzal P, Waldman S, Papini M, et al.

Heliyon, 2017 Oct;3(10):e00420.
PMID: 29034340 DOI: 10.1016/j.heliyon.2017.e00420

In an attempt to combat the possibility of bacterial infection and insufficient bone growth around metallic, surgical implants, bioactive glasses may be employed as coatings. In this work, silica-based and borate-based glass series were synthesized for this purpose and subsequently characterized in terms of antibacterial behavior, solubility and cytotoxicity. Borate-based glasses were found to exhibit significantly superior antibacterial properties and increased solubility compared to their silica-based counterparts, with BRT0 and BRT3 (borate-based glasses with 0 and 15 mol% of titanium dioxide incorporated, respectively) outperforming the remainder of the glasses, both borate and silicate based, in these respects. Atomic Absorption Spectroscopy confirmed the release of zinc ions (Zn(2+)), which has been linked to the antibacterial abilities of glasses SRT0, BRT0 and BRT3, with inhibition effectively achieved at concentrations lower than 0.7 ppm. In vitro cytotoxicity studies using MC3T3-E1 osteoblasts confirmed that cell proliferation was affected by all glasses in this study, with decreased proliferation attributed to a faster release of sodium ions over calcium ions in both glass series, factor known to slow cell proliferation in vitro.

Matched MeSH terms: Zinc
Fulltext Gadolinium-Doped Gallic Acid-Zinc/Aluminium-Layered Double Hydroxide/Gold Theranostic Nanoparticles for a Bimodal Magnetic Resonance Imaging and Drug Delivery System

Sani Usman M, Hussein MZ, Fakurazi S, Masarudin MJ, Ahmad Saad FF

Nanomaterials (Basel), 2017 Aug 31;7(9).
PMID: 28858229 DOI: 10.3390/nano7090244

We have developed gadolinium-based theranostic nanoparticles for co-delivery of drug and magnetic resonance imaging (MRI) contrast agent using Zn/Al-layered double hydroxide as the nanocarrier platform, a naturally occurring phenolic compound, gallic acid (GA) as therapeutic agent, and Gd(NO₃)₃ as diagnostic agent. Gold nanoparticles (AuNPs) were grown on the system to support the contrast for MRI imaging. The nanoparticles were characterized using techniques such as Hi-TEM, XRD, ICP-ES. Kinetic release study of the GA from the nanoparticles showed about 70% of GA was released over a period of 72 h. The in vitro cell viability test for the nanoparticles showed relatively low toxicity to human cell lines (3T3) and improved toxicity on cancerous cell lines (HepG2). A preliminary contrast property test of the nanoparticles, tested on a 3 Tesla MRI machine at various concentrations of GAGZAu and water (as a reference) indicates that the nanoparticles have a promising dual diagnostic and therapeutic features to further develop a better future for clinical remedy for cancer treatment.

Matched MeSH terms: Zinc
Role of dissolved oxygen on the degradation mechanism of Reactive Green 19 and electricity generation in photocatalytic fuel cell

Lee SL, Ho LN, Ong SA, Wong YS, Voon CH, Khalik WF, et al.

Chemosphere, 2018 Mar;194:675-681.
PMID: 29247929 DOI: 10.1016/j.chemosphere.2017.11.166

In this study, a membraneless photocatalytic fuel cell with zinc oxide loaded carbon photoanode and platinum loaded carbon cathode was constructed to investigate the impact of dissolved oxygen on the mechanism of dye degradation and electricity generation of photocatalytic fuel cell. The photocatalytic fuel cell with high and low aeration rate, no aeration and nitrogen purged were investigated, respectively. The degradation rate of diazo dye Reactive Green 19 and the electricity generation was enhanced in photocatalytic fuel cell with higher dissolved oxygen concentration. However, the photocatalytic fuel cell was still able to perform 37% of decolorization in a slow rate (k = 0.033 h-1) under extremely low dissolved oxygen concentration (approximately 0.2 mg L-1) when nitrogen gas was introduced into the fuel cell throughout the 8 h. However, the change of the UV-Vis spectrum indicates that the intermediates of the dye could not be mineralized under insufficient dissolved oxygen level. In the aspect of electricity generation, the maximum short circuit current (0.0041 mA cm-2) and power density (0.00028 mW cm-2) of the air purged photocatalytic fuel cell was obviously higher than that with nitrogen purging (0.0015 mA cm-2and 0.00008 mW cm-2).

Matched MeSH terms: Zinc Oxide
Fulltext Experimental study on electromagnetic-assisted ZnO nanofluid flooding for enhanced oil recovery (EOR)

Adil M, Lee K, Mohd Zaid H, Ahmad Latiff NR, Alnarabiji MS

PLoS One, 2018;13(2):e0193518.
PMID: 29489897 DOI: 10.1371/journal.pone.0193518

Recently, nano-EOR has emerged as a new frontier for improved and enhanced oil recovery (IOR & EOR). Despite their benefits, the nanoparticles tend to agglomerate at reservoir conditions which cause their detachment from the oil/water interface, and are consequently retained rather than transported through a porous medium. Dielectric nanoparticles including ZnO have been proposed to be a good replacement for EOR due to their high melting point and thermal properties. But more importantly, these particles can be polarized under electromagnetic (EM) irradiation, which provides an innovative smart Nano-EOR process denoted as EM-Assisted Nano-EOR. In this study, parameters involved in the oil recovery mechanism under EM waves, such as reducing mobility ratio, lowering interfacial tensions (IFT) and altering wettability were investigated. Two-phase displacement experiments were performed in sandpacks under the water-wet condition at 95°C, with permeability in the range of 265-300 mD. A crude oil from Tapis oil field was employed; while ZnO nanofluids of two different particle sizes (55.7 and 117.1 nm) were prepared using 0.1 wt. % nanoparticles that dispersed into brine (3 wt. % NaCl) along with SDBS as a dispersant. In each flooding scheme, three injection sequential scenarios have been conducted: (i) brine flooding as a secondary process, (ii) surfactant/nano/EM-assisted nano flooding, and (iii) second brine flooding to flush nanoparticles. Compare with surfactant flooding (2% original oil in place/OOIP) as tertiary recovery, nano flooding almost reaches 8.5-10.2% of OOIP. On the other hand, EM-assisted nano flooding provides an incremental oil recovery of approximately 9-10.4% of OOIP. By evaluating the contact angle and interfacial tension, it was established that the degree of IFT reduction plays a governing role in the oil displacement mechanism via nano-EOR, compare to mobility ratio. These results reveal a promising way to employ water-based ZnO nanofluid for enhanced oil recovery purposes at a relatively high reservoir temperature.

Matched MeSH terms: Zinc Oxide

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links