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Fulltext Structural and morphology of ZnO nanorods synthesized using ZnO seeded growth hydrothermal method and its properties as UV sensing

Ridhuan NS, Razak KA, Lockman Z, Abdul Aziz A

PLoS One, 2012;7(11):e50405.
PMID: 23189199 DOI: 10.1371/journal.pone.0050405

In this study, zinc oxide (ZnO) nanorod arrays were synthesized using a simple hydrothermal reaction on ZnO seeds/n-silicon substrate. Several parameters were studied, including the heat-treatment temperature to produce ZnO seeds, zinc nitrate concentration, pH of hydrothermal reaction solution, and hydrothermal reaction time. The optimum heat-treatment temperature to produce uniform nanosized ZnO seeds was 400°C. The nanorod dimensions depended on the hydrothermal reaction parameters. The optimum hydrothermal reaction parameters to produce blunt tip-like nanorods (770 nm long and 80 nm in top diameter) were 0.1 M zinc nitrate, pH 7, and 4 h of growth duration. Phase analysis studies showed that all ZnO nanorods exhibited a strong (002) peak. Thus, the ZnO nanorods grew in a c-axis preferred orientation. A strong ultraviolet (UV) emission peak was observed for ZnO nanorods grown under optimized parameters with a low, deep-level emission peak, which indicated high optical property and crystallinity of the nanorods. The produced ZnO nanorods were also tested for their UV-sensing properties. All samples responded to UV light but with different sensing characteristics. Such different responses could be attributed to the high surface-to-volume ratio of the nanorods that correlated with the final ZnO nanorods morphology formed at different synthesis parameters. The sample grown using optimum synthesis parameters showed the highest responsivity of 0.024 A/W for UV light at 375 nm under a 3 V bias.

Matched MeSH terms: Zinc Oxide/chemistry*; Zinc Compounds/chemistry
Fulltext Investigation into mass loading sensitivity of sezawa wave mode-based surface acoustic wave sensors

Mohanan AA, Islam MS, Ali SH, Parthiban R, Ramakrishnan N

Sensors (Basel), 2013;13(2):2164-75.
PMID: 23389346 DOI: 10.3390/s130202164

In this work mass loading sensitivity of a Sezawa wave mode based surface acoustic wave (SAW) device is investigated through finite element method (FEM) simulation and the prospects of these devices to function as highly sensitive SAW sensors is reported. A ZnO/Si layered SAW resonator is considered for the simulation study. Initially the occurrence of Sezawa wave mode and displacement amplitude of the Rayleigh and Sezawa wave mode is studied for lower ZnO film thickness. Further, a thin film made of an arbitrary material is coated over the ZnO surface and the resonance frequency shift caused by mass loading of the film is estimated. It was observed that Sezawa wave mode shows significant sensitivity to change in mass loading and has higher sensitivity (eight times higher) than Rayleigh wave mode for the same device configuration. Further, the mass loading sensitivity was observed to be greater for a low ZnO film thickness to wavelength ratio. Accordingly, highly sensitive SAW sensors can be developed by coating a sensing medium over a layered SAW device and operating at Sezawa mode resonance frequency. The sensitivity can be increased by tuning the ZnO film thickness to wavelength ratio.

Matched MeSH terms: Zinc Oxide
Fulltext High-performance dye-sensitized solar cells based on morphology-controllable synthesis of ZnO-ZnS heterostructure nanocone photoanodes

Rouhi J, Mamat MH, Ooi CH, Mahmud S, Mahmood MR

PLoS One, 2015;10(4):e0123433.
PMID: 25875377 DOI: 10.1371/journal.pone.0123433

High-density and well-aligned ZnO-ZnS core-shell nanocone arrays were synthesized on fluorine-doped tin oxide glass substrate using a facile and cost-effective two-step approach. In this synthetic process, the ZnO nanocones act as the template and provide Zn2+ ions for the ZnS shell formation. The photoluminescence spectrum indicates remarkably enhanced luminescence intensity and a small redshift in the UV region, which can be associated with the strain caused by the lattice mismatch between ZnO and ZnS. The obtained diffuse reflectance spectra show that the nanocone-based heterostructure reduces the light reflection in a broad spectral range and is much more effective than the bare ZnO nanocone and nanorod structures. Dye-sensitized solar cells based on the heterostructure ZnO-ZnS nanocones are assembled, and high conversion efficiency (η) of approximately 4.07% is obtained. The η improvement can be attributed primarily to the morphology effect of ZnO nanocones on light-trapping and effectively passivating the interface surface recombination sites of ZnO nanocones by coating with a ZnS shell layer.

Matched MeSH terms: Zinc Oxide/chemistry*; Zinc Compounds/chemistry*
Fulltext Enhanced photoluminescence and Raman properties of Al-Doped ZnO nanostructures prepared using thermal chemical vapor deposition of methanol assisted with heated brass

Thandavan TM, Gani SM, San Wong C, Md Nor R

PLoS One, 2015;10(3):e0121756.
PMID: 25756598 DOI: 10.1371/journal.pone.0121756

Vapor phase transport (VPT) assisted by mixture of methanol and acetone via thermal evaporation of brass (CuZn) was used to prepare un-doped and Al-doped zinc oxide (ZnO) nanostructures (NSs). The structure and morphology were characterized by field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). Photoluminescence (PL) properties of un-doped and Al-doped ZnO showed significant changes in the optical properties providing evidence for several types of defects such as zinc interstitials (Zni), oxygen interstitials (Oi), zinc vacancy (Vzn), singly charged zinc vacancy (VZn-), oxygen vacancy (Vo), singly charged oxygen vacancy (Vo+) and oxygen anti-site defects (OZn) in the grown NSs. The Al-doped ZnO NSs have exhibited shifted PL peaks at near band edge (NBE) and red luminescence compared to the un-doped ZnO. The Raman scattering results provided evidence of Al doping into the ZnO NSs due to peak shift from 145 cm-1 to an anomalous peak at 138 cm-1. Presence of enhanced Raman signal at around 274 and 743 cm-1 further confirmed Al in ZnO NSs. The enhanced D and G band in all Al-doped ZnO NSs shows possible functionalization and doping process in ZnO NSs.

Matched MeSH terms: Zinc/chemistry*; Zinc Oxide/chemistry*
Microwave assisted hydrothermal method for porous zinc oxide nanostructured-films

Ridha NJ, Umar AA, Alosfur F, Jumali MH, Salleh MM

J Nanosci Nanotechnol, 2013 Apr;13(4):2667-74.
PMID: 23763142

Porous ZnO nanostructures have become the subject of research interest--due to their special structures with high surface to volume ratio that may produce peculiar properties for use in optoelectronics, sensing and catalysis applications. A microwave-assisted hydrothermal method has been used for effecting the formation of porous nanostructure of metaloxide materials, such as CoO and SnO2, in solution. Here, by adopting the unique performance of a microwave-assisted-hydrothermal method, we realized the formation of highly porous ZnO nanostructures directly on the substrate surface, instead of in solution. The effects of the ambient reaction conditions and the microwave power on the structural growth of the ZnO nanostructures were studied in detail. Two different ambient reaction conditions, namely refluxed and isolated in autoclave systems, were used in this work. Porous ZnO (PZO) nanostructures with networked-nanoflakes morphology is the typical result for this approach. It was found that the morphology of the ZnO nanostructures was strongly depended on the ambient conditions of the reaction; the isolated-autoclave system may produce reasonably high porous ZnO that is constituted by vertically oriented grainy-flakes structures, whereas the refluxed system produced solid vertically-oriented flake structures. The microwave power did not influence the structural growth of the ZnO. It was also found that both the ambient reaction conditions and the microwave power used influenced the crystallographic orientation of the PZO. For instance, PZO with dominant (002) Bragg plane could be obtained by using refluxed system, whereas PZO with dominant (101) plane could be realized if using isolated system. For the case of microwave power, the crystallographic orientation of PZO prepared using both systems changed from dominant (002) to (101) planes if the power was increased. The mechanism for the formation of porous ZnO nanostructures using the present approach is proposed. The ZnO nanostructures prepared using the present method should find an extensive use in currently existing application due to its property of reasonably high porosity.

Matched MeSH terms: Zinc Oxide
Production cross-sections of radionuclides from α-induced reactions on natural copper up to 50MeV

Usman AR, Khandaker MU, Haba H, Otuka N, Murakami M, Komori Y

Appl Radiat Isot, 2016 08;114:104-13.
PMID: 27227905 DOI: 10.1016/j.apradiso.2016.04.027

The excitation functions were measured for the (nat)Cu(α,x)(66,67)Ga,(65)Zn,(57,58,60)Co reactions in the energy range of 16.5 -50MeV. A conventional stacked-foil activation technique combined with HPGe γ-ray spectrometry was employed to determine cross-sections. The measured cross-sections were critically compared with relevant previous experimental data and also with the evaluated data in the TENDL-2014 library. Present results confirmed some of the previous experimental data, whereas only a partial agreement was found with the evaluated data. The measured data are useful for reducing the existing discrepancies in the literature, to improve the nuclear reaction model codes, and to enrich the experimental database towards various applications.

Matched MeSH terms: Zinc
Fulltext Band Gap Narrowing and Widening of ZnO Nanostructures and Doped Materials

Kamarulzaman N, Kasim MF, Rusdi R

Nanoscale Res Lett, 2015 Dec;10(1):1034.
PMID: 26319225 DOI: 10.1186/s11671-015-1034-9

Band gap change in doped ZnO is an observed phenomenon that is very interesting from the fundamental point of view. This work is focused on the preparation of pure and single phase nanostructured ZnO and Cu as well as Mn-doped ZnO for the purpose of understanding the mechanisms of band gap narrowing in the materials. ZnO, Zn0.99Cu0.01O and Zn0.99Mn0.01O materials were prepared using a wet chemistry method, and X-ray diffraction (XRD) results showed that all samples were pure and single phase. UV-visible spectroscopy showed that materials in the nanostructured state exhibit band gap widening with respect to their micron state while for the doped compounds exhibited band gap narrowing both in the nano and micron states with respect to the pure ZnO materials. The degree of band gap change was dependent on the doped elements and crystallite size. X-ray photoelectron spectroscopy (XPS) revealed that there were shifts in the valence bands. From both UV-visible and XPS spectroscopy, it was found that the mechanism for band gap narrowing was due to the shifting of the valance band maximum and conduction band minimum of the materials. The mechanisms were different for different samples depending on the type of dopant and dimensional length scales of the crystallites.

Matched MeSH terms: Zinc Oxide
Bacterial nanocellulose and its application in heavy metals and dyes removal: a review

Sahari NS, Shahir S, Ibrahim Z, Hasmoni SH, Altowayti WAH

Environ Sci Pollut Res Int, 2023 Nov;30(51):110069-110078.
PMID: 37814051 DOI: 10.1007/s11356-023-30067-w

This review discusses the application of bacterial nanocellulose (BNC) and modified BNC in treating wastewater containing heavy metals and dye contaminants. It also highlights the challenges and future perspectives of BNC and its composites. Untreated industrial effluents containing toxic heavy metals are systematically discharged into public waters. In particular, lead (Pb), copper (Cu), cadmium (Cd), nickel (Ni), zinc (Zn), and arsenic (As) are very harmful to human health and, in some cases, may lead to death. Several methods such as chemical precipitation, ion exchange, membrane filtration, coagulation, and Fenton oxidation are used to remove these heavy metals from the environment. However, these methods involve the use of numerous chemicals whilst producing high amount of toxic sludge. Meanwhile, the development of the adsorption-based technique has provided an alternative way of treating wastewater using BNC. Bacterial nanocellulose requires less energy for purification and has higher purity than plant cellulose. In general, the optimum growth parameters are crucial in BNC production. Even though native BNC can be used for the removal of heavy metals and dyes, the incorporation of other materials, such as polyethyleneimine, graphene oxide, calcium carbonate and polydopamine can improve sorption efficiencies.

Matched MeSH terms: Zinc
Fulltext Interventions for managing taste disturbances

Kumbargere Nagraj S, George RP, Shetty N, Levenson D, Ferraiolo DM, Shrestha A

Cochrane Database Syst Rev, 2017 Dec 20;12(12):CD010470.
PMID: 29260510 DOI: 10.1002/14651858.CD010470.pub3

BACKGROUND: The sense of taste is very much essential to the overall health of an individual. It is a necessary component to enjoy one's food, which in turn provides nutrition to an individual. Any disturbance in taste perception can hamper quality of life in such patients by influencing their appetite, body weight and psychological well-being. Taste disorders have been treated using different modalities of treatment and there is no consensus for the best intervention. Hence this Cochrane Review was undertaken. This is an update of the Cochrane Review first published in November 2014.
OBJECTIVES: To assess the effects of interventions for the management of patients with taste disturbances.
SEARCH METHODS: Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 4 July 2017); the Cochrane Central Register of Controlled Trials (CENTRAL; 2017 Issue 6) in the Cochrane Library (searched 4 July 2017); MEDLINE Ovid (1946 to 4 July 2017); Embase Ovid (1980 to 4 July 2017); CINAHL EBSCO (1937 to 4 July 2017); and AMED Ovid (1985 to 4 July 2017). The US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for trials. Abstracts from scientific meetings and conferences were searched on 25 September 2017. No restrictions were placed on the language or date of publication when searching the electronic databases.
SELECTION CRITERIA: We included all randomised controlled trials (RCTs) comparing any pharmacological agent with a control intervention or any non-pharmacological agent with a control intervention. We also included cross-over trials in the review.
DATA COLLECTION AND ANALYSIS: Two pairs of review authors independently, and in duplicate, assessed the quality of trials and extracted data. Wherever possible, we contacted trial authors for additional information. We collected adverse events information from the trials.
MAIN RESULTS: We included 10 trials (581 participants), nine of which we were able to include in the quantitative analyses (566 participants). We assessed three trials (30%) as having a low risk of bias, four trials (40%) at high risk of bias and three trials (30%) as having an unclear risk of bias. We only included studies on taste disorders in this review that were either idiopathic, or resulting from zinc deficiency or chronic renal failure.Of these, nine trials with 544 people compared zinc supplements to placebo for patients with taste disorders. The participants in two trials were children and adolescents with respective mean ages of 10 and 11.2 years and the other seven trials had adult participants. Out of these nine, two trials assessed the patient-reported outcome for improvement in taste acuity using zinc supplements (risk ratio (RR) 1.40, 95% confidence interval (CI) 0.94 to 2.09; 119 participants, very low-quality evidence). We meta-analysed for taste acuity improvement using objective outcome (continuous data) in idiopathic and zinc-deficient taste disorder patients (standardised mean difference (SMD) 0.44, 95% CI 0.23 to 0.65; 366 participants, three trials, very low-quality evidence). We also analysed one cross-over trial separately using the first half of the results for taste detection (mean difference (MD) 2.50, 95% CI 0.93 to 4.07; 14 participants, very low-quality evidence), and taste recognition (MD 3.00, 95% CI 0.66 to 5.34; 14 participants, very low-quality evidence). We meta-analysed taste acuity improvement using objective outcome (dichotomous data) in idiopathic and zinc-deficient taste disorder patients (RR 1.42, 95% 1.09 to 1.84; 292 participants, two trials, very low-quality evidence). Out of the nine trials using zinc supplementation, four reported adverse events like eczema, nausea, abdominal pain, diarrhoea, constipation, decrease in blood iron, increase in blood alkaline phosphatase, and minor increase in blood triglycerides.One trial tested taste discrimination using acupuncture (MD 2.80, 95% CI -1.18 to 6.78; 37 participants, very low-quality evidence). No adverse events were reported in the acupuncture trial.None of the included trials could be included in the meta-analysis for health-related quality of life in taste disorder patients.
AUTHORS' CONCLUSIONS: We found very low-quality evidence that was insufficient to conclude on the role of zinc supplements to improve taste acuity reported by patients and very low-quality evidence that zinc supplements improve taste acuity in patients with zinc deficiency/idiopathic taste disorders. We did not find any evidence to conclude the role of zinc supplements for improving taste discrimination, or any evidence addressing health-related quality of life due to taste disorders.We found very low-quality evidence that is not sufficient to conclude on the role of acupuncture for improving taste discrimination in cases of idiopathic dysgeusia (distortion of taste) and hypogeusia (reduced ability to taste). We were unable to draw any conclusions regarding the superiority of zinc supplements or acupuncture as none of the trials compared these interventions.

Matched MeSH terms: Zinc/deficiency; Zinc Compounds/adverse effects; Zinc Compounds/therapeutic use*
Effects of zinc oxide nanoparticles on growth performance and concentrations of malondialdehyde, zinc in tissues, and corticosterone in broiler chickens under heat stress conditions

Ramiah SK, Awad EA, Mookiah S, Idrus Z

Poult Sci, 2019 Sep 01;98(9):3828-3838.
PMID: 30839088 DOI: 10.3382/ps/pez093

The use of nanominerals, such as nano-zinc, represents a promising and emerging technology in the animal farming industry. Due to the small particle size and bioavailability of nano-zinc, it can be easily assimilated in the digestive system, thereby reducing excretion and environmental pollution. The present study was conducted to assess the effects of zinc oxide nanoparticles (ZnONPs) on the growth performance, zinc (Zn) concentration in edible tissues, thiobarbituric acid reactive substance, and corticosterone concentrations in broilers reared under normal or heat stress environmental conditions. The experiment was performed with a completely randomized design based on a 4 × 2 factorial arrangement consisting of 4 diets (basal diet + 60 mg/kg conventional zinc oxide as control diet; basal diet + 40 mg/kg of ZnONPs; basal diet + 60 mg/kg of ZnONPs; and basal diet + 100 mg/kg of ZnONPs) and 2 environmental conditions (normal and heat stress). On day 22, birds from each dietary group were divided equally to normal temperature (23 ± 1°C throughout) or heat stress conditions (34 ± 1°C daily for 6 h from 10:00 am until 4:00 pm). From 1 to 42 D of age, the broiler chickens fed 100 mg/kg ZnONPs exhibited lower feed intake and feed conversion ratio than the control. The accumulation of Zn in the liver of broilers was significantly higher among all treatment groups compared to breast and thigh muscle tissues regardless of the temperature conditions. At 40 and 60 mg/kg ZnONPs, the malondialdehyde content increased in thigh muscle of broilers at 7 D postmortem, indicating that ZnONPs potentially inhibited the antioxidant system in muscle tissues. The control and ZnONPs at 40 mg/kg and 60 mg/kg led to low serum corticosterone levels that may be attributed to the antioxidant and antistress properties of Zn. Taken together, although supplementation with ZnONPs at 40 mg/kg and 60 mg/kg alleviated the negative results of heat stress, further research is needed to determine the optimal level of dietary ZnONPs supplementation.

Matched MeSH terms: Zinc/metabolism*; Zinc Oxide/administration & dosage; Zinc Oxide/metabolism*
Fulltext Preparation and characterization of an anti-inflammatory agent based on a zinc-layered hydroxide-salicylate nanohybrid and its effect on viability of Vero-3 cells

Ramli M, Hussein MZ, Yusoff K

Int J Nanomedicine, 2013;8:297-306.
PMID: 23345976 DOI: 10.2147/IJN.S38858

A new organic-inorganic nanohybrid based on zinc-layered hydroxide intercalated with an anti-inflammatory agent was synthesized through direct reaction of salicylic acid at various concentrations with commercially available zinc oxide. The basal spacing of the pure phase nanohybrid was 15.73 Å, with the salicylate anions arranged in a monolayer form and an angle of 57 degrees between the zinc-layered hydroxide interlayers. Fourier transform infrared study further confirmed intercalation of salicylate into the interlayers of zinc-layered hydroxide. The loading of salicylate in the nanohybrid was estimated to be around 29.66%, and the nanohybrid exhibited the properties of a mesoporous-type material, with greatly enhanced thermal stability of the salicylate compared with its free counterpart. In vitro cytotoxicity assay revealed that free salicylic acid, pure zinc oxide, and the nanohybrid have a mild effect on viability of African green monkey kidney (Vero-3) cells.

Matched MeSH terms: Zinc Oxide/pharmacology; Zinc Oxide/chemistry; Zinc Compounds/pharmacology; Zinc Compounds/chemistry*
Influence of Amaranth dye concentration on the efficiency of hybrid system of photocatalytic fuel cell and Fenton process

Nordin N, Ho LN, Ong SA, Ibrahim AH, Wong YS, Lee SL, et al.

Environ Sci Pollut Res Int, 2017 Oct;24(29):23331-23340.
PMID: 28840563 DOI: 10.1007/s11356-017-9964-7

A novel sustainable hybrid system of photocatalytic fuel cell (PFC) and Fenton process is an alternative wastewater treatment technology for energy-saving and efficient treatment of organic pollutants. The electrons generated from PFC photoanode are used to produce H2O2 in the Fenton reactor and react with the in situ generation of Fe2+ from sacrificial iron for hydroxyl radical formation. In this study, the effect of different initial Amaranth dye concentrations on degradation and electricity generation were investigated. ZnO/Zn photoanode was prepared by anodizing method and characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Results revealed that the maximum power density (9.53 mW/m2) and current density (0.0178 mA/m2) were achieved at 10 mg/L of Amaranth. The correlation between dye degradation, voltage output, and kinetic photocatalytic degradation were also investigated and discussed.

Matched MeSH terms: Zinc; Zinc Oxide
Fulltext Effect of Printing Parameters on Tensile, Dynamic Mechanical, and Thermoelectric Properties of FDM 3D Printed CABS/ZnO Composites

Aw YY, Yeoh CK, Idris MA, Teh PL, Hamzah KA, Sazali SA

Materials (Basel), 2018 Mar 22;11(4).
PMID: 29565286 DOI: 10.3390/ma11040466

Fused deposition modelling (FDM) has been widely used in medical appliances, automobile, aircraft and aerospace, household appliances, toys, and many other fields. The ease of processing, low cost and high flexibility of FDM technique are strong advantages compared to other techniques for thermoelectric polymer composite fabrication. This research work focuses on the effect of two crucial printing parameters (infill density and printing pattern) on the tensile, dynamic mechanical, and thermoelectric properties of conductive acrylonitrile butadiene styrene/zinc oxide (CABS/ZnO composites fabricated by FDM technique. Results revealed significant improvement in tensile strength and Young's modulus, with a decrease in elongation at break with infill density. Improvement in dynamic storage modulus was observed when infill density changed from 50% to 100%. However, the loss modulus and damping factor reduced gradually. The increase of thermal conductivity was relatively smaller compared to the improvement of electrical conductivity and Seebeck coefficient, therefore, the calculated figure of merit (ZT) value increased with infill density. Line pattern performed better than rectilinear, especially in tensile properties and electrical conductivity. From the results obtained, FDM-fabricated CABS/ZnO showed much potential as a promising candidate for thermoelectric application.

Matched MeSH terms: Zinc; Zinc Oxide
Fulltext Adsorption of acid dyes onto Zinc Chloride-Modified Cocoa (Theobroma Cacao) pod Husk-based carbon

Nur Aqilah Zainal, Shariff Ibrahim, Borhannuddin Arifin

Pertanika Journal of Science & Technology, 2017;25(103):129-138.
MyJurnal

An agricultural waste, the cocoa pod husk was chemically modified using a dehydrating agent, zinc chloride (ZnCl2), carbonised and used for the remediation of acid dyes in an aqueous solution. The targeted acid dyes are: (i) Acid Violet 17 (AV17); (ii) Acid Yellow 36 (AY36); and (iii) Acid Blue 29 (AB29). The physicochemical properties of the zinc chloride-modified cocoa pod husk-based carbon (ZCPHC) were characterised by ash content, bulk density, pH slurry, pHpzc and Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-Ray (EDX) analysis. The bulk density and ash content of the prepared carbon is 0.55 g cm-1 and 7.0% respectively. The photograph of SEM shows distinct changes at the ZCPHC carbon surface as it has large pores formed due to ZnCl2 modification. The adsorption tests were performed in a batch adsorption system using an aqueous solution of the understudy acid dyes. The influence of pH and dose of an adsorbent on the acid dye uptake was investigated and discussed. The adsorption was in favour at acidic condition with maximum removal observed at pH 2. The removal efficiency of the aqueous acid dye solution increased with the increase in adsorbent dosage. The kinetic experiment showed equilibrium time is less than 40 minutes and the kinetic data for all three understudy acid dyes fitted well with the pseudo-second-order model with a correlation coefficient (R2) values above 0.98.

Matched MeSH terms: Zinc; Zinc Compounds
Fulltext Zinc/Aluminium⁻Quinclorac Layered Nanocomposite Modified Multi-Walled Carbon Nanotube Paste Electrode for Electrochemical Determination of Bisphenol A

Zainul R, Abd Azis N, Md Isa I, Hashim N, Ahmad MS, Saidin MI, et al.

Sensors (Basel), 2019 Feb 22;19(4).
PMID: 30813385 DOI: 10.3390/s19040941

This paper presents the application of zinc/aluminium-layered double hydroxide-quinclorac (Zn/Al-LDH-QC) as a modifier of multiwalled carbon nanotubes (MWCNT) paste electrode for the determination of bisphenol A (BPA). The Zn/Al-LDH-QC/MWCNT morphology was examined by a transmission electron microscope and a scanning electron microscope. Electrochemical impedance spectroscopy was utilized to investigate the electrode interfacial properties. The electrochemical responses of the modified electrode towards BPA were thoroughly evaluated by using square-wave voltammetry technique. The electrode demonstrated three linear plots of BPA concentrations from 3.0 × 10-8⁻7.0 × 10-7 M (R² = 0.9876), 1.0 × 10-6⁻1.0 × 10-5 M (R² = 0.9836) and 3.0 × 10-5⁻3.0 × 10-4 M (R² = 0.9827) with a limit of detection of 4.4 × 10-9 M. The electrode also demonstrated good reproducibility and stability up to one month. The presence of several metal ions and organic did not affect the electrochemical response of BPA. The electrode is also applicable for BPA determination in baby bottle and mineral water samples with a range of recovery between 98.22% and 101.02%.

Matched MeSH terms: Zinc; Zinc Compounds
Surface morphological and mechanical properties of zinc oxide eugenol using different types of ZnO nanopowder

Bakhori SKM, Mahmud S, Mohamad D, Masudi SM, Seeni A

Mater Sci Eng C Mater Biol Appl, 2019 Jul;100:645-654.
PMID: 30948101 DOI: 10.1016/j.msec.2019.03.034

Zinc oxide eugenol (ZOE) cements are generally made up of 80%-90% ZnO powder while the remaining content consists of eugenol bonding resin. ZnO structure plays a major role in the morphology and mechanical properties of ZOE. In this study, we investigated the effects of different particle sizes/shapes of ZnO particles on the surface and mechanical properties of ZOE. Three samples were prepared namely ZnO-Ax, ZnO-B and ZnO-K. The crystallite sizes calculated from XRD were 37.76 nm (ZnO-Ax), 39.46 nm (ZnO-B) and 42.20 nm (ZnO-K) while the average particle sizes obtained by DLS were 21.11nm (ZnO-Ax), 56.73 nm (ZnO-B) and 2012 nm (ZnO-K). Results revealed that the compressive strengths of ZOE-Ax and ZOE-B were improved by 87.92% and 57.16%, respectively, relative to that of commercial ZOE-K. Vickers hardness test demonstrated that the hardness of ZOE-Ax and ZOE-B also increased by 74.9% and 31.1%, respectively. The ZnO-Ax nanostructure possessed a small average particle size (21.11 nm), a homogeneous size distribution (DLS) and an oxygen-rich surface (from EDS and elemental mapping). Meanwhile, ZnO-B exhibited a slightly larger average particle size of 56.73 nm compared with that of other samples. Sample ZnO-Ax demonstrated the highest compressive strength which was attributed to its large particle surface area (21.11 nm particle size) that provided a large contact area and greater interfacial (or interlock) bonding capability if compared to that of ZnO-K sample (2012 nm particle size).

Matched MeSH terms: Zinc Oxide/chemistry*
Acrylic-based genosensor utilizing metal salphen labeling approach for reflectometric dengue virus detection

Mazlan NF, Tan LL, Karim NHA, Heng LY, Jamaluddin ND, Yusof NYM, et al.

Talanta, 2019 Jun 01;198:358-370.
PMID: 30876573 DOI: 10.1016/j.talanta.2019.02.036

An optical genosensor based on Schiff base complex (Zn2+ salphen) DNA label and acrylic microspheres (AMs) as polymer support of the capturing DNA probe (cpDNA) was developed for dengue virus serotype 2 (DEN-2) detection via reflectance spectrophotometric method. The solid-state optical DNA biosensor showed high selectivity and specificity up to one-base mismatch in the target DNA sequence owing to the salphen chemical structure that is rich in localized electrons, and allowed π-π stacking interaction between stacked base pairs of double-stranded DNA (dsDNA). The reflectometric DNA microsensor demonstrated a broad linear detection range towards DEN-2 DNA from 1 × 10-15 M to 1 × 10-3 M with a low limit of detection (LOD) obtained at 1.21 × 10-16 M. The DNA biosensor gave reproducible optical response with a satisfactory relative standard deviation (RSD) at 3.1%, (n = 3), and the reflectance response was stable even after four regeneration cycles of the DNA biosensor. The optical genosensor was proven comparable with standard reverse transcription polymerase chain reaction (RT-PCR) in detecting DEN-2 genome acquired from clinical samples of serum, urine and saliva of dengue virus infected patients under informed consent. The developed reflectometric DNA biosensor is advantageous in offering an early DEN-2 diagnosis, when fever symptom started to manifest in patient.

Matched MeSH terms: Zinc/chemistry*
The combined effect of dental post and cement materials on fracture resistance and fracture mode of endodontically-treated teeth

Mohamed Abdulmunem, Hadijah Binti Abdullah, Noor Hayaty Binti Abu Kasim, Ali Dabbagh

Sains Malaysiana, 2015;44:1189-1194.

The aim of this study was to investigate the simultaneous influence of various dental posts and cementation materials on the fracture resistance and failure mode of the endodontically-treated teeth. Sixty endodontically treated upper central incisors were randomly divided into two main groups, each consisted of three subgroups restored with titanium, fiber and stainless steel posts. The posts in the first and second groups were luted with zinc phosphate and composite resin cements, respectively. Composite cores were built-up over the specimens and then retained with nickel-chromium crowns. Specimens were thermocycled and then loaded at 135o until failures were observed. The obtained data of fracture resistances and failure modes were analyzed using Two-way ANOVA and the Chi-Square tests, respectively. The results showed that the zinc phosphate cement resulted in relatively higher fracture resistances. However, luting of dental posts with composite resin provided more restorable failures in endodontically-treated teeth. Moreover, the teeth restored by fiber posts exhibited desirable fracture resistances with more restorable failure modes, compared with those restored by titanium or stainless steel posts.

Matched MeSH terms: Zinc Phosphate Cement; Zinc Compounds
Fulltext Solution-Based Synthesis and Characterization of Cu2ZnSnS4 (CZTS) Thin Films

Syafiq U, Ataollahi N, Maggio RD, Scardi P

Molecules, 2019 Sep 23;24(19).
PMID: 31547625 DOI: 10.3390/molecules24193454

Cu2ZnSnS4 (CZTS) ink was synthesized from metal chloride precursors, sulfur, and oleylamine (OLA), as a ligand by a simple and low-cost hot-injection method. Thin films of CZTS were then prepared by spin coating, followed by thermal annealing. The effects of the fabrication parameters, such as ink concentration, spinning rate, and thermal treatment temperatures on the morphology and structural, optical, and electrical properties of the films were investigated. As expected, very thin films, for which the level of transmittance and band-gap values increase, can be obtained either by reducing the concentration of the inks or by increasing the rate of spinning. Moreover, the thermal treatment affects the phase formation and crystallinity of the film, as well as the electrical conductivity, which decreases at a higher temperature.

Matched MeSH terms: Zinc/chemistry*
Fulltext Poly(2,6-Dimethyl-1,4-Phenylene Oxide)-Based Hydroxide Exchange Separator Membranes for Zinc-Air Battery

Abbasi A, Hosseini S, Somwangthanaroj A, Mohamad AA, Kheawhom S

Int J Mol Sci, 2019 Jul 26;20(15).
PMID: 31357565 DOI: 10.3390/ijms20153678

Rechargeable zinc-air batteries are deemed as the most feasible alternative to replace lithium-ion batteries in various applications. Among battery components, separators play a crucial role in the commercial realization of rechargeable zinc-air batteries, especially from the viewpoint of preventing zincate (Zn(OH)42-) ion crossover from the zinc anode to the air cathode. In this study, a new hydroxide exchange membrane for zinc-air batteries was synthesized using poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) as the base polymer. PPO was quaternized using three tertiary amines, including trimethylamine (TMA), 1-methylpyrolidine (MPY), and 1-methylimidazole (MIM), and casted into separator films. The successful synthesis process was confirmed by proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy, while their thermal stability was examined using thermogravimetric analysis. Besides, their water/electrolyte absorption capacity and dimensional change, induced by the electrolyte uptake, were studied. Ionic conductivity of PPO-TMA, PPO-MPY, and PPO-MIM was determined using electrochemical impedance spectroscopy to be 0.17, 0.16, and 0.003 mS/cm, respectively. Zincate crossover evaluation tests revealed very low zincate diffusion coefficient of 1.13 × 10-8, and 0.28 × 10-8 cm2/min for PPO-TMA, and PPO-MPY, respectively. Moreover, galvanostatic discharge performance of the primary batteries assembled using PPO-TMA and PPO-MPY as initial battery tests showed a high specific discharge capacity and specific power of ~800 mAh/gZn and 1000 mWh/gZn, respectively. Low zincate crossover and high discharge capacity of these separator membranes makes them potential materials to be used in zinc-air batteries.

Matched MeSH terms: Zinc/chemistry*

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