ZnO with two different morphologies were used to study the inhibition of Streptococcus sobrinus and Streptococcus mutans which are closely associated with tooth cavity. Rod-like shaped ZnO-A and plate-like shaped ZnO-B were produced using a zinc boiling furnace. The nanopowders were characterized using energy filtered transmission electron microscopy (EFTEM), X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, Raman spectroscopy and dynamic light scattering (DLS) to confirm the properties of the ZnO polycrystalline wurtzite structures. XRD results show that the calculated crystallite sizes of ZnO-A and ZnO-B were 36.6 and 39.4nm, respectively, whereas DLS revealed particle size distributions of 21.82nm (ZnO-A) and 52.21nm (ZnO-B). PL spectra showed ion vacancy defects related to green and red luminescence for both ZnO particles. These defects evolved during the generation of reactive oxygen species which contributed to the antibacterial activity. Antibacterial activity was investigated using microdilution technique towards S. sobrinus and S. mutans at different nanopowder concentrations. Results showed that ZnO-A exhibited higher inhibition on both bacteria compared with ZnO-B. Moreover, S. mutans was more sensitive compared with S. sobrinus because of its higher inhibition rate.
Emotional maturity (EM) is defined as the ability of an individual to respond to situations, control emotions, and behave in an adult manner when dealing with others. EM is associated with adult learning skill, which is an important aspect of professional development as stated in the principles of andragogy. These principles are basically a characteristic feature of adult learning, which is defined as "the entire range of formal, non-formal, and informal learning activities that are undertaken by adults after an initial education and training, which result in the acquisition of new knowledge and skills". The purpose of this study is to find out the influence of EM on adult learning among Years I and II medical students of Universiti Sultan Zainal Abidin (UniSZA). The study population included preclinical medical students of UniSZA from Years I and II of the academic session 2015/2016. The convenient sampling technique was used to select the sample. Data were collected using "EM scale" to evaluate emotional level and adult learning scale to assess the adult learning scores. Out of 120 questionnaires, only six response sheets were not complete and the remaining 114 (95%) were complete. Among the study participants, 23.7% (27) and 76.3% (87) were males and females, respectively. The data were then compiled and analyzed using SPSS Version 22. The Pearson's correlation method was used to find the significance of their association. The results revealed a significant correlation between EM and adult learning scores (r=0.40, p<0.001). Thus, the study result supports the prediction, and based on the current findings, it can be concluded that there is a significant correlation between EM and adult learning and it has an effect on the students. Medical faculty members should give more emphasis on these aspects to produce health professionals. Henceforward, researchers can expect with optimism that the country will create more rational medical doctors.
This study aimed to determine the effect of cooking on phytate content and the inhibitory effects of phytate on the bioavailability of minerals in eight Malaysian soy based dishes. Phytate was analyzed by using anion-exchange chromatography while minerals were analyzed by using Atomic Absorption Spectrophotometer. Molar ratios were obtained by dividing the mole of phytate to minerals. Phytate content was reduced in cooked dishes compared to the raw ones but it was not significantly different (P > 0.05). Raw, cooked and whole dish soy products contained 257.14-900.00, 182.14-803.57 and 289.29-910.71 mg/100 g phytate, respectively. Boiling and steaming have reduced most phytate content in the food samples. Molar ratios for phytate/minerals in these samples (phytate/Ca >0.17; phytate/Fe >1) indicated that phytate content inhibited the absorption of calcium and iron. However, the ratio for Ca × phytate/Zn in all samples was less than 200 which showed that phytate did not affect the bioavailability of zinc.
Fourteen sediment samples were collected along Linggi River, Malaysia. Neutron activation analysis (NAA) and inductively coupled plasma-mass spectrometry (ICP-MS) techniques were used in the determination of toxic element contents. The results showed that As, Cd and Sb concentrations were higher at all sampling stations, with enrichment factor values ranging from 17.7 to 75.0, 2.1 to 19.5 and 6.6 to 28.4, respectively. Elements of Pb and Zn) were also enriched at most of the sampling stations whilst Cu, Cr and Ni were shown as background levels. The sediment of Linggi River can be categorised as low (<8.0) to very high degree of contamination (>32.0). The mean concentrations of elements viz. Cd, Cr, Ni, Pb, Sb and Zn were lower than the threshold effect level (TEL) of FSQGs values except for As. The concentration of As (arsenic) was higher than PEL and PEC of FSQGs values.
Proteins of the DUF866 superfamily are exclusively found in eukaryotic cells. A member of the DUF866 superfamily, C1ORF123, is a human protein found in the open reading frame 123 of chromosome 1. The physiological role of C1ORF123 is yet to be determined. The only available protein structure of the DUF866 family shares just 26% sequence similarity and does not contain a zinc binding motif. Here, we present the crystal structure of the recombinant human C1ORF123 protein (rC1ORF123). The structure has a 2-fold internal symmetry dividing the monomeric protein into two mirrored halves that comprise of distinct electrostatic potential. The N-terminal half of rC1ORF123 includes a zinc-binding domain interacting with a zinc ion near to a potential ligand binding cavity. Functional studies of human C1ORF123 and its homologue in the fission yeast Schizosaccharomyces pombe (SpEss1) point to a role of DUF866 protein in mitochondrial oxidative phosphorylation.
Highly weathered basaltic rock was exposed at PSK profile of Kuantan, Segamat Highway. The weathering profile from fresh rock soil can be observed at PKJ profile at Kg. Jabi Quarry. Twelve rock and soil samples from PSK profile and thirteen samples from PKJ profile have been collected for geochemical analysis. The objective of the analysis is to establish the behaviour of several major and trace elements in the weathering profile of the basaltic rock. The samples were analysed by XRF and XRD techniques. Petrographic study was done on fresh rock samples and concretions. The concentration of major elements (TiO2, Al2O3 and Fe2O3) appear to be increased with the increasing of the degree of weathering whereas the concentration of SiO2 and CaO are decreased. There is a clear correlation between Fe2O3 + Al2O3 with L.O.I as well as between Fe2O3 with Al2O3. Behaviour of the trace elements (Ni, Co, Cr and Zn) against the weathering process are totally different. The secondary minerals (kaolinite, nactire, geothite, hematite and gibbsite) appear to control the behaviour of the major and trace elements.
Batuan basalt yang terluluhawa sepenuhnya telah dicerap di lokaliti PSK Lebuhraya Segamat-Kuantan. Profil luluhawa yang boleh dilihat perubahan daripada batuan segar hingga tanih didapati di lokaliti PKJ Kuari Kg. Jabi. Dua contoh profil dengan masing-masing 12 sampel dan 13 sample tanih telah dikaji untuk menentukan perlakuan beberapa unsur major dan unsur surih batuan basalt yang terluluhawa. Kaedah analisis yang digunakan ialah pendarflour sinar-X (XRF) dan pembelauan sinar-X (XRF). Kajian petrografi pula dibuat pada sampel batuan segar dan sampel konkresi. Nilai unsur major TiO2, Al2O3 dan Fe2O3 bertambah dengan bertambahnya darjah luluhawa manakala SiO2 dan CaO menyusut. Hubungan korelasi Fe2O3 + Al2O3 dengan L.O.I dan Fe2O3 denagn Al2O3 adalah jelas. Unsur surih nikel (Ni) kobalt (Co), kromium (Cr) dan zink (Zn) mempunyai perlakuan yang berbeza-beza dengan luluhawa. Perlakuan yang ditunjukkan oleh unsur major dan surih tersebut dikawal oleh mineral sekunder (koalinit, nakrit, geotit, hematit dan gibsit).
Poly(hydroxamic acid) ion exchange resin was evaluated for speciation of iron(II) and iron(III) ions. Distribution coefficients indicate that the resin is more selective towards iron(III) ion. Column extractions show that iron(III) ion is quantatively extracted from sulfuric acid solutions at concentrations of between 0.01 to 0.00lM but only 2% or less of iron(II) ion is retained under these conditions. Further studies show that these two ions can be separated and their separations are not affected by the presence of nickel, zinc, copper, calcium, chloride, bromide, nitrate and sulphate.
Resin penukar ion poli(asid hidroksamik) telah dikaji untuk penspesiesan ion-ionferum. Pekali taburan menunjukkan resin ini mempunyai kepilihan yang tinggi terhadap ion ferik berbanding dengan ionferus. Pengekstrakan dengan kaedah turus mendapati ion ferik dari larutan asid sulfurik 0.01 dan 0.00lM boleh diesktrak secara kuantitatif manakala pengekstrakan ion ferus hanya 2% atau lebih kecil. Kajian lanjut menunjukkan resin ini boleh memisahkan ion ferik dari ion ferus dan pemisahan ini tidak diganggu oleh kehadiran ion-ion nikel, zink, kuprum, kalsium, klorida, bromida, nitrat dan sulfat.
A study of the heavy metal bio-accumulation by fresh water fish, Tilapia nilotica around Lohan Dam was carried out in aquarium system. The study showed that the fish tissues cultured in contaminated water samples, (location S3 and 54) contain higher heavy metals concentration compared with the fish cultured in uncontaminated water samples (S1 and S2). The concentrations of Fe, Zn, Mn, Cu, Ni and Cr in fish tissues are higher compared with those of Co, Cd and Pb. The bio-accumulation rates of Zn, Mn, Cu, Ni and Co are 25 times higher than those of the base levels and 10 times higher than those of the controls. The heavy metal bio-accumulation order in T. nilotica is as follows: Mn> Cu> Cr> Ni> Co> Zn> Pb> Cd> Fe. The heavy metal intakes by fish during the experimental period did not exceed the level concentration levels.
Kajian bioakumulasi logam berat oleh ikan air tawar, Tilapia nilotica di perairan sekitar Empangan Lohan dilakukan dengan kaedah ternakan akuarium. Hasil kajian menunjukkan tisu ikan yang diternak dalam sampel air tercemar (lokasi S3 dan S4) mengandungi logam berat yang lebih tinggi dari tisu ikan yang diternak dalam sampel air tidak tercemar (lokasi S1 dan S2). Kepekatan logam berat seperti Fe, Zn, Mn, Cu, Ni dan Cr didapati tinggi dalam tisu ikan berbanding dengan kepekatan Co, Cd dan Pb. Kadar bioakumulasi logam berat daIam ikan didapati tinggi bagi Zn, Mn, Cu, Ni dan Co yang masing-masing melebihi 25 kali ganda dari paras asal dan lebih 10 kali ganda dari paras kawalan. Siri bioakumulasi logam berat yang dikaji dalam ikan T. nilotica menurut urutan; Mn> Cu> Cr> Ni> Co> Zn> Pb> Cd> Fe. Kepekatan logam berat yang dapat diambil oleh ikan dalam masa kajian tidak mencapai nilai yang dapat menyebabkan kematian kepada ikan.
In this study, heavy metal data (including four geochemical fractions) from offshore and intertidal sediments collected off the west coast of Peninsular Malaysia were analyzed using factor analysis. A similarity was found when comparing between offshore and intertidal sediments, where out of the 20 variables, five factors (resistant Cu, total Cu, resistant Pb, total Pb and total Zn) could be clearly selected on the basis of their high loadings as derived by factor analysis in both sediment sampling areas. However, the statistical outputs based on the present study using factor analysis cannot be practically acceptable mainly because the resistant fractions are not of anthropogenic origins and ecotoxicologists are more concern on the anthropogenic ones. Only a modification using a specific normalizing agent such as the nonresistant fraction, should be tested to show feasibility of the contribution of anthropogenic sources in the two sampling areas. However, a more comprehensive metal monitoring data should be compiled to complement the results obtainable from factor analysis, before a valid Malaysian Marine Sediment Pollution Index or Sediment Quality Guidelines, can be proposed to be established.
Heavy metal pollution leads to human health problems and represents a constant threat to the environment. Pollutant
clean-up using conventional methods are often hampered by high cost and ineffective pollutant removal. Phytoremediation
technique is a preferable alternative due to its minimal side effects to the environment in addition to reasonable treatment
cost. In this study, we investigated the potential of Centella asiatica and Orthosiphon stamineus as phytoremediation
agents. Both species were grown in contaminated soil obtained from industrial land. Plant growth response and their
ability to accumulate and translocate zinc, copper and lead were assessed. From this study, root growth of C. asiatica
was compromised when grown in contaminated soil. Copper was highly accumulated in C. asiatica roots while the
leaves were more concentrated with zinc and lead. Conversely, all three tested metals were highly detected in the roots
of O. stamineus, although the root elongation was not adversely affected. Low amount of metals in the stems of both
species permits longer stem length. Correlation study showed that the accumulation of zinc, copper and lead in plant
tissues varies depending on plant species and the type of metals. Based on the bioaccumulation, translocation and
enrichment factor, our study showed that C. asiatica was tolerant towards zinc, copper and lead; hence suitable for
phytoextraction. By contrast, O. stamineus acted as a moderate accumulator of the tested metal elements.
The aim of this study was to investigate the genotoxicity effect of Cd and Zn and their binary mixtures in tilapia fish Oreochromis niloticus using the micronucleus test. Two cytogenetic end points were considered; the frequencies of micronucleated cells and nuclear abnormalities. Fishes were exposed to 4.63 mg/L Cd, 7.50 mg/L Zn and 4.63 mg/L Cd + 7.50 mg/L Zn mixture for the period of 24, 48, 72 and 96 h. The results showed that the frequencies of micronuclei and nuclear abnormalities in the erythrocyte were significantly increased in all groups of treatments when compared with the control group (0 exposures). In addition, the highest frequencies of micronucleated and nuclear abnormalities were obtained after 48 h exposure in almost all cases (except in the mixture of Cd+Zn) and decreased after 72 and 96 h exposure. Frequencies of micronuclei and erythrocytes with nuclear abnormalities exposed to a mixture of Cd+Zn in O. niloticus were always lower at all-time points (after 24, 48, 72 and 96 h) than that of a single Cd and Zn exposure. Therefore, the study demonstrated that the genotoxic potential of these metal compounds and the simultaneous treatment of Cd and Zn suggest the presence of antagonistic interactions.
Characterisation of the leaching behaviour of coal fly ash from Tenaga Nasional Berhad (TNB) by using tank leaching test method has been reported. The leachability of the constituents such as major elements and toxic metals in the coal fly ash was studied. Eight renewed leachant solutions after 6 hours, 1, 2, 5, 8, 21, 36 and 64 days were investigated after filtration. The parameters namely pH, cumulative release regarding the major elements and toxic metals to duration were presented. The results showed that the pH solutions increased from pH 4 to neutral and remained stable during the test. It might have resulted from the large buffering capacity of the coal fly ashes. Five major elements namely Al, Ca, K, Mg and Na were detected with Ca concentration in the leachant solutions was the highest for all samples. Toxic metals such as As, Ba, Co, Cr, Mn, Ni, Pb, Se and Zn were found and the test showed consistent results on the As, Ba, Mn, Se and Zn in leachant solutions. The findings also showed that some of the toxic metal concentrations namely As, Ba, Cr, Pb and Se exceeded the maximum allowance of the guideline of drinking water quality in Malaysia and WHO. Obviously, proper waste management has to be applied in this scenario.
This study was carried out by using Centella asiatica grown using a hydroponic system under laboratory conditions to study synergistic and antagonistic effects of Zn bioaccumulation with added Pb and the changes in antioxidant activities in leaves and roots of C. asiatica. The antioxidant activities included superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and guaiacol peroxidase (GPX). The treatments Zn (2 ppm) + Pb (0.4 ppm) and Zn (4 ppm) + Pb (0.6 ppm) increased the accumulation of Zn in leaves by 14.06 and 16.84%, respectively, but decreased by 7.36% uptake in roots (Zn 4 ppm + Pb 0.6 ppm). This showed that Pb and Zn acted synergistically to Zn accumulation in leaves but antagonistically in roots. CAT and SOD activities in leaves were increased when Zn was added together with Pb. In roots, CAT, APX and SOD activities were increased but GPX was decreased. Owing to their sensitivities to Zn with Pb, SOD and CAT could be used as biomarkers to monitor the toxicity of Pb and Zn exposure in the leaves and roots of C. asiatica.
In this work, the structural properties of radio frequency sputtering-grown zinc oxide (ZnO) thin films on sapphire (Al203), gallium arsenide (GaAs) and n-type silicon (Si) substrates were characterized. Scanning electron microscopy was employed to study the surface morphology of the samples. X-ray diffraction (xRD) measurements were also performed to obtain the structural information of the samples. The xRD results showed that the ZnO layers grown on different substrates have similar lattice constant (c) values, which were used to calculate the strain percentages of the ZnO thin films. The surface morphologies of the ZnO thin films indicated the formation of a granular surface when ZnO is deposited on n-type Si(100) and Si( 111 ) substrates. Meanwhile, a leaf-like surface is obtained when ZnO is deposited on GaAs and Al203 substrates. The results showed that the ZnO thin film grown on n-type Si(100) has the best quality among all the samples.
Removal of ciprofloxacin (CIP) pollutant from wastewater using conventional process is particularly challenging due to poor removal efficiency. In this work, CIP was photocatalytically degraded using a porous ZnO/SnS2 photocatalyst prepared via microwaves. The influence of process parameters (e.g., pH, catalyst mass and initial CIP concentration) and radical scavengers on visible-light induced degradation of CIP on the catalyst was investigated. From the study, it was found that visible-light induced degradation of CIP on ZnO/SnS2 is a surface-mediated process and the reaction kinetics followed the Langmuir-Hinshelwood first-order kinetics. It was found that the optimum condition for CIP degradation was at pH of 6.1 and catalyst dosage of 500 mg L-1. Higher catalyst dosage however led to a decline in reaction rate due to light scattering effect and reduction in light penetration.
Zinc selenide/graphene oxide (ZnSe/GO) composite is synthesized using hydrothermal method. Two different methods
such as direct and indirect route have been investigated to form the ZnSe/GO composite. In this research, the graphene
oxide used was in sheet and liquid form. The synthesized composite was then characterized using X-ray diffraction (XRD)
for phase identification, field emission scanning electron microscopy (FESEM) for morphology analysis and ultravioletvisible
spectroscopy (UV-Vis) for optical properties. ZnSe/GO composite showed absorption peak ranging from 460 to
480 nm with the optical band gap obtained through Tauc equation. The optical band gap of the ZnSe/GO composite has
been tuned down to a smaller value as compared to the bulk ZnSe compound. The optical band gap has been reduced
to around 2.53 eV when liquid graphene oxide was used while around 2.23 to 2.32 eV when graphene oxide sheet was
used. The purity of ZnSe/GO composite synthesis via indirect hydrothermal method is higher than those synthesized via
direct hydrothermal method. The type of graphene oxide will affect the morphology of the composite where the ZnSe
compound was either wrapped by tiny thorn-like substance or graphene oxide layer.
Due to the increasing production and use of nanoparticles in various sectors such as electronic industries and healthcare,
concerns about the unknown effects caused by the presence of these materials in the natural environment and agricultural
systems were on the rise. Because of the growing trend of ZnO nanoparticles (nZnO) which is one of the most widely
used nanoparticles being released into the environment, it has attracted the attention for more studies to be done on
the effects of this nanoparticle on organisms. This study was carried out to investigate the phytotoxicity effect of nZnO
on groundnut seedlings in Murashige and Skoog (MS) medium. The experimental treatments of this study include eight
concentrations of nZnO (10, 30, 50, 100, 200, 400, 1000 & 2000 mg.L-1) added to MS medium and MS medium without
nanoparticles have been used as control treatment. For the first 6 days after sowing, germination percent and germination
rate index were calculated by counting the germinated seeds every day. Groundnut seedlings were incubated for 3 weeks
in optimum condition and after that, seedling characteristics such as length, wet and dry weight of radicle and plumule
were measured. The water content of radicle and plumule were also calculated. The results of this study showed that
radicle and plumule length of groundnut seedlings were affected by nZnO exposure, in a way that length of radicles in 50
mg.L-1 nZnO and higher concentrations was significantly lower than that of control treatment and the shortest plumule
length was observed in 2000 mg.L-1 nZnO concentration treatment. Both the radicle and plumule wet weight were also
decreased as the nanoparticle concentration was increased. However, despite the decreasing in radicle and plumule dry
weight with increasing in nZnO concentration, this increase was not significant. However radicle dry weight in 10 mg.L-1
nZnO was significantly higher than nZnOtreatments with 200 mg.L-1 concentration and higher concentrations. Moreover,
observations of this study did not show any significant difference between the water content of nZnO concentration
treatments and control treatment.
Technical benefit of incorporation of Palm Oil Clinker (POC) in cement-based applications has been proven in recent
studies. The aim of this work was to assess the heavy metal leaching behavior to ensure environmental safety of using
POC in cement-based applications. The chemical composition, morphology, total organic carbon (TOC) and mineralogy
were determined using XRF, FESEM, TOC analyzers and XRD to select appropriate chemical reagents for complete digestion.
HNO3
, HF and HClO4
were used for digestion of POC to measure heavy metal content using ICP-MS. The chemical reagents
CH3
COOH, NH2
OH-HCl, H2
O2
+CH3
COONH4
and HF+HNO3
+HCl were used for extraction of acid soluble, reducible,
oxidizable and residual fractions of heavy metals in POC, respectively. The leaching toxicity of the POC was investigated
by the USEPA 1311 TCLP method. The result showed the presence of Be, V, Cr, Ni, Cu, Zn, As, Se, Ag, Cd, Ba and Pb with
levels of 5.13, 11.02, 2.65, 1.93, 45.43, 11.84, 15.07, 0, 0, 81.97 and 1.76 mg/kg, respectively, in POC. The leaching value
in mg/L of As (4.56), Cu(1.05), Be (0.89), Zn(0.51), Ba(0.26), Ni (0.17), V(0.15), Cr(0.001) and Se (0.001) is found well
below the standard limit of risk. Risk assessment code (RAC) analysis confirms the safe incorporation of POC in cementbased
applications.
This study is focused on the determination of trace metals (Cr, Cu, Zn, As, Pb, and Cd) concentrations of nine different indigenous fish species of Meghna River in Bangladesh to know the possible risk in human consumption. Fishes' wet muscles samples were analyzed to evaluate the level of trace metal concentrations. The concentrations (mg kg-1 w/w) of the six selected trace metals were in the order Zn (1.42 ± 0.12) > Cr (1.31 ± 0.08) > Cu (0.92 ± 0.09) > Pb (0.54 ± 0.07) > Cd (0.51 ± 0.07) > As (0.47 ± 0.02). The results revealed that all the selected trace metals were below the maximum permissible limits recommended by the reference standards. The fish species may pose no risk with respect to the Estimated Daily Intake (EDI). Target hazard quotient (THQ) values for Cr, Cu, Zn, Pb, and Cd in all the fish species were <1.0, except for As which is dominantly organic in fishes. Both adults and children are vulnerable to carcinogenic health threat due to Cd exposure.
This study performs natural sand-based synthesis using the sonochemical route for preparing Zn-doped magnetite nanoparticles. The nanoparticles were dispersed in water as a carrier liquid to form Zn-doped magnetite aqueous ferrofluids. Structural data analysis indicated that the Zn-doped magnetite nanoparticles formed a nanosized spinel structure. With an increase in the Zn content, the lattice parameters of the Zn-doped magnetite nanoparticles tended to increase because Zn2+ has a larger ionic radius than those of Fe3+ and Fe2+. The existence of Zn-O and Fe-O functional groups in tetrahedral and octahedral sites were observed in the wavenumber range of 400-700 cm-1. The primary particles of the Zn-doped magnetite ferrofluids tended to construct chain-like structures with fractal dimensions of 1.2-1.9. The gas-like compression (GMC) plays as a better model than the Langevin theory to fit the saturation magnetization of the ferrofluids. The ferrofluids exhibited a superparamagnetic character, with their magnetization was contributed by aggregation. The Zn-doped magnetite ferrofluids exhibited excellent antibacterial activity against gram-positive and negative bacteria. It is suggested that the presence of the negatively charged surface and the nanoparticle size may contribute to the high antibacterial activity of Zn-doped magnetite ferrofluids and making them potentially suitable for advanced biomedical.