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Tunable photoelectrochemical performance of Au/BiFeO3 heterostructure

Huang YL, Chang WS, Van CN, Liu HJ, Tsai KA, Chen JW, et al.

Nanoscale, 2016 Aug 25;8(34):15795-801.
PMID: 27533610 DOI: 10.1039/c6nr04997d

Ferroelectric photoelectrodes, other than conventional semiconductors, are alternative photo-absorbers in the process of water splitting. However, the capture of photons and efficient transfer of photo-excited carriers remain as two critical issues in ferroelectric photoelectrodes. In this work, we overcome the aforementioned issues by decorating the ferroelectric BiFeO3 (BFO) surface with Au nanocrystals, and thus improving the photoelectrochemical (PEC) performance of BFO film. We demonstrate that the internal field induced by the spontaneous polarization of BFO can (1) tune the efficiency of the photo-excited carriers' separation and charge transfer characteristics in bare BFO photoelectrodes, and (2) modulate an extra optical absorption within the visible light region, created by the surface plasmon resonance excitation of Au nanocrystals to capture more photons in the Au/BFO heterostructure. This study provides key insights for understanding the tunable features of PEC performance, composed of the heterostructure of noble metals and ferroelectric materials.

Matched MeSH terms: Metals
Triple-Indicator-Based Multidimensional Colorimetric Sensing Platform for Heavy Metal Ion Detections

Idros N, Chu D

ACS Sens, 2018 09 28;3(9):1756-1764.
PMID: 30193067 DOI: 10.1021/acssensors.8b00490

Heavy metals are highly toxic at trace levels and their pollution has shown great threat to the environment and public health worldwide where current detection methods require expensive instrumentation and laborious operation, which can only be accomplished in centralized laboratories. Herein, we report a low-cost, paper-based microfluidic analytical device (μPAD) for facile, portable, and disposable monitoring of mercury, lead, chromium, nickel, copper, and iron ions. Triple indicators or ligands that contain ions or molecules are preloaded on the μPADs and upon addition of a metal ion, the colorimetric indicators will elicit color changes observed by the naked eyes. The color features were quantitatively analyzed in a three-dimensional space of red, green, and blue or the RGB-space using digital imaging and color calibration techniques. The sensing platform offers higher accuracy for cross references, and is capable of simultaneous detection and discrimination of different metal ions in even real water samples. It demonstrates great potential for semiquantitative and even qualitative analysis with a sensitivity below the safe limit concentrations, and a controlled error range.

Matched MeSH terms: Metals, Heavy/analysis*
Trend in metals variation in Tasik Chini, Pahang, Peninsular Malaysia

Shuhaimi-Othman M, Mushrifah I, Lim EC, Ahmad A

Environ Monit Assess, 2008 Aug;143(1-3):345-54.
PMID: 17987397

Water from 15 sampling stations in Tasik Chini (Chini Lake), Peninsular Malaysia were sampled for 12 months from September 2004 until August 2005 and analyzed for 11 metals including iron (Fe), aluminum (Al), manganese (Mn), barium (Ba), zinc (Zn), lead (Pb), copper (Cu), cadmium (Cd), nickel (Ni), chromium (Cr) and cobalt (Co). Results showed that the mean (min-max) metal concentrations (in micrograms per liter) in Tasik Chini waters for the 12 months sampling based on 15 sampling stations (in descending order) for Fe, Al, Mn, Ba, Zn, Pb, Cu and Cd were 794.84 (309.33-1609.07), 194.53 (62.37-665.93), 29.16 (16.68-79.85), 22.07 (15.64-29.71), 5.12 (2.224-6.553), 2.36 (1.165-4.240), 0.832 (0.362-1.443) and 0.421 (0.254-0.696) respectively. Concentration for three metals i.e. Ni, Cr and Co were too low and not detected by the graphite furnace Atomic Absorption Spectrophotometry (AAS). Comparison with various water quality standards showed that the mean metals concentration in surface water of Tasik Chini were low and within the range of natural background except for Fe and Al. In general, metal concentrations in Tasik Chini water varied temporally and spatially. The main factors influencing these metal concentrations in the water were the raining season and mining activities. Stations located at Tanjung Jerangking and Melai areas were the most effected due to those factors.

Matched MeSH terms: Metals, Heavy/analysis*
Fulltext Treatment of river water of Sg. Pusu by using magnesium oxide (MGO) coated with chitosan

Nik Nur Syafika Pahri, Nur Huda Syazwani Jafri, Husna Ahmad Tajuddin, Yusilawati Ahmad Nor

Biological and Natural Resources Engineering Journal, 2019;2(1):10-25.
MyJurnal

Effective treatment of wastewater is crucial in order to achieve a sustainable development. For instance, highly efficient treatment processes with low capital requirements are the major prerequisite for implementation of the advanced wastewater treatment operations. Among various available treatment methods, the application of coagulation-flocculation process by using natural coagulant; chitosan has vast advantages such as low operating cost, environmental friendly and highly effective in the wastewater treatment operations. The application of nanotechnology in numerous treatment techniques are considered as the most significant advances in water and wastewater treatment practices. The utilization of magnesium oxide (MgO) as nano-adsorbent has recently gained attention as a potential treatment method in water remediation particularly for treating effluents with high amount of organic dyes and heavy metals due to its high treatment efficiency, low cost, versatility and environment compatibility. The purpose of this study was to determine the effectiveness of coagulation-flocculation process when using novel coagulant in which MgO coated with chitosan by investigating the percentage removal of several significant parameters which were turbidity, chemical oxygen demand (COD) and suspended solid. The removal efficiencies were determined throughout a series of experiments carried out using a standard jar test procedure in which three different coagulants; chitosan, MgO coated with chitosan and MgO were tested on water samples taken from Sg. Pusu. In addition, a set of experiments was designed using response surface methodology (RSM) in order to optimize adsorption of chitosan into MgO. The experiments were conducted at various concentrations of chitosan (10-30 mg/ml) and selected MgO dosage ranges (10-30 mg). From the obtained results, it was found that chitosan-MgO coagulant has good removal efficiencies of turbidity, chemical oxygen demand (COD) and suspended solids at 92%, 91%, and 98% respectively from the optimization of adsorption of chitosan-MgO. The MgO coated with chitosan is the best coagulant in this study compared to chitosan and MgO alone because of the ability of treating the river water with up to 90 % removal for all the main parameters. The results showed that coagulation-flocculation is effective as a treatment for treating river water.

Matched MeSH terms: Metals, Heavy
Fulltext Transfer free graphene growth on SiO2 substrate at 250 °C

Vishwakarma R, Rosmi MS, Takahashi K, Wakamatsu Y, Yaakob Y, Araby MI, et al.

Sci Rep, 2017 03 02;7:43756.
PMID: 28251997 DOI: 10.1038/srep43756

Low-temperature growth, as well as the transfer free growth on substrates, is the major concern of graphene research for its practical applications. Here we propose a simple method to achieve the transfer free graphene growth on SiO2 covered Si (SiO2/Si) substrate at 250 °C based on a solid-liquid-solid reaction. The key to this approach is the catalyst metal, which is not popular for graphene growth by chemical vapor deposition. A catalyst metal film of 500 nm thick was deposited onto an amorphous C (50 nm thick) coated SiO2/Si substrate. The sample was then annealed at 250 °C under vacuum condition. Raman spectra measured after the removal of the catalyst by chemical etching showed intense G and 2D peaks together with a small D and intense SiO2 related peaks, confirming the transfer free growth of multilayer graphene on SiO2/Si. The domain size of the graphene confirmed by optical microscope and atomic force microscope was about 5 μm in an average. Thus, this approach will open up a new route for transfer free graphene growth at low temperatures.

Matched MeSH terms: Metals
Trace metals geochemistry for health assessment coupled with adsorption remediation method for the groundwater of Lorong Serai 4, Hulu Langat, west coast of Peninsular Malaysia

Usman UA, Yusoff I, Raoov M, Hodgkinson J

Environ Geochem Health, 2020 Oct;42(10):3079-3099.
PMID: 32180058 DOI: 10.1007/s10653-020-00543-0

The research study was carried out to evaluate trace metals (Pb, Cd, Se, Al, Mn, Cu, Zn, Fe, As, Ni, Cr, and Ag) concentrations in groundwater of Lorong Serai 4, Hulu Langat, Selangor, Malaysia. Additionally, the research study focused on determining non-carcinogenic and carcinogenic health risks, sources of the contaminants, and effective remediation methods. The results show that the concentration levels of Pb, Cd, Se, Al, Cu, Zn, Ni, Cr, and Ag are lower than their corresponding permissible limits, while Fe, Mn, and As concentrations exceed their acceptable limit. The hazard index of the groundwater in the area exceeded the acceptable limit, showing the rate of carcinogenic and non-carcinogenic health effects associated with the water. The findings also indicate that the lifetime cancer risk is high compared to the maximum limits of lifetime cancer risk from the drinking water (10-6 to 10-4). The groundwater geochemical data of the area are used in establishing the source of Fe, Mn, and As metal ions. Evaluation of Fe2+/Fe3+ and S2-/SO42- redox couples and thermodynamic modelling indicates that the groundwater of the area is in redox disequilibrium. The groundwater samples contain aqueous iron sulphate, which is supersaturated, ferrous carbonate and aluminium sulphate that are saturated. The main state of redox disequilibrium is governed by mineral precipitation and dissolution. Aqueous arsenic and manganese are possibly derived from the dissolution of pyrite (arsenopyrite) and amorphous oxide-hydroxides, respectively. The high concentration of iron in the shallow groundwater in the area is primarily the result of silicate rock weathering of ferroan igneous and metamorphic minerals with a minor contribution from the oxidation of iron sulphides. Magnetite coated with graphene oxide (Fe3O4-GO) nanoparticles (NPs) was synthesized and characterized, and the adsorption preliminary experiments were carried out; and the Fe3O4-GO NPs show enhanced removal (Fe > As > Mn) capacity over graphene oxide (GO).

Matched MeSH terms: Metals/analysis*
Fulltext Trace metals contamination in groundwater and implications on human health: comprehensive assessment using hydrogeochemical and geostatistical methods

Brindha K, Paul R, Walter J, Tan ML, Singh MK

Environ Geochem Health, 2020 Nov;42(11):3819-3839.
PMID: 32601907 DOI: 10.1007/s10653-020-00637-9

Monitoring the groundwater chemical composition and identifying the presence of pollutants is an integral part of any comprehensive groundwater management strategy. The present study was conducted in a part of West Tripura, northeast India, to investigate the presence and sources of trace metals in groundwater and the risk to human health due to direct ingestion of groundwater. Samples were collected from 68 locations twice a year from 2016 to 2018. Mixed Ca-Mg-HCO3, Ca-Cl and Ca-Mg-Cl were the main groundwater types. Hydrogeochemical methods showed groundwater mineralization due to (1) carbonate dissolution, (2) silicate weathering, (3) cation exchange processes and (4) anthropogenic sources. Occurrence of faecal coliforms increased in groundwater after monsoons. Nitrate and microbial contamination from wastewater infiltration were apparent. Iron, manganese, lead, cadmium and arsenic were above the drinking water limits prescribed by the Bureau of Indian Standards. Water quality index indicated 1.5% had poor, 8.7% had marginal, 16.2% had fair, 66.2% had good and 7.4% had excellent water quality. Correlation and principal component analysis reiterated the sources of major ions and trace metals identified from hydrogeochemical methods. Human exposure assessment suggests health risk due to high iron in groundwater. The presence of unsafe levels of trace metals in groundwater requires proper treatment measures before domestic use.

Matched MeSH terms: Metals/analysis*
Trace metal (Cd, Cu, Fe, Mn, Ni and Zn) accumulation in Scleractinian corals: a record for Sabah, Borneo

Mokhtar MB, Praveena SM, Aris AZ, Yong OC, Lim AP

Mar Pollut Bull, 2012 Nov;64(11):2556-63.
PMID: 22901962 DOI: 10.1016/j.marpolbul.2012.07.030

This study was designed as the first to assess the trace metal (Cd, Cu, Fe, Mn, Ni and Zn) in coral skeleton in relation to metal availabilities and sampling locations in Sabah. The study also aims to determine the differential abilities of Scleractinian coral species as a bioindicator of environmental conditions. Skeletons of Scleractinian coral (Hydnophora microconos, Favia speciosa and Porites lobata) showed concentrations of Fe, Mn and Ni relatively higher than Cd and Zn in the skeletons. Statistical analyses outputs showed significant relationships between trace metal concentrations in coral species and those in seawater and sediment. The highest bioaccumulation factors among three Scleractinian coral species investigated was for Zn followed by Mn, Ni, Fe, Cd and Cu can provide a sign about pollution levels. However, metal tolerance, coral structure and morphology as well as multispecies monitoring are factors that need to be a focus in future studies.

Matched MeSH terms: Metals/analysis*
Toxicological evaluation of some Malaysian locally processed raw food products

Sharif R, Ghazali AR, Rajab NF, Haron H, Osman F

Food Chem Toxicol, 2008 Jan;46(1):368-74.
PMID: 17900779

Malaysian locally processed raw food products are widely used as main ingredients in local cooking. Previous studies showed that these food products have a positive correlation with the incidence of cancer. The cytotoxicity effect was evaluated using MTT assay (3-(4,5-dimetil-2-thiazolil)-2,5-diphenyl-2H-tetrazolium bromide) against Chang liver cells at 2000 microg/ml following 72 h incubation. Findings showed all methanol extracts caused a tremendous drop in the percentage of cell viability at 2000 microg/ml (shrimp paste - 41.69+/-3.36%, salted fish - 37.2+/-1.06%, dried shrimp - 40.32+/-1.8%, p<0.05). To detect DNA damage in a single cell, alkaline Comet Assay was used. None of the extracts caused DNA damage to the Chang liver cells at 62.5 microg/ml following 24 h incubation, as compared to the positive control, hydrogen peroxide (tail moment - 9.50+/-1.50; tail intensity - 30.50+/-2.50). Proximate analysis which was used for the evaluation of macronutrients in food showed that shrimp paste did not comply with the protein requirement (<25%) as in Food Act 1983. Salt was found in every sample with the highest percentage being detected in shrimp paste which exceeded 20%. Following heavy metal analysis (arsenic, cadmium, lead and mercury), arsenic was found in every sample with dried shrimps showing the highest value as compared to the other samples (6.16 mg/kg). In conclusion, several food extracts showed cytotoxic effect but did not cause DNA damage against Chang liver cells. Salt was found as the main additive and arsenic was present in every sample, which could be the probable cause of the toxicity effects observed.

Matched MeSH terms: Metals, Heavy/analysis; Metals, Heavy/toxicity
Fulltext Toxicity of metals to a freshwater snail, Melanoides tuberculata

Shuhaimi-Othman M, Nur-Amalina R, Nadzifah Y

ScientificWorldJournal, 2012;2012:125785.
PMID: 22666089 DOI: 10.1100/2012/125785

Adult freshwater snails Melanoides tuberculata (Gastropod, Thiaridae) were exposed for a four-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn) concentrations. Mortality was assessed and median lethal times (LT₅₀) and concentrations (LC₅₀) were calculated. LT₅₀ and LC₅₀ increased with the decrease in mean exposure concentrations and times, respectively, for all metals. The LC(50) values for the 96-hour exposures to Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 0.14, 1.49, 3.90, 6.82, 8.46, 8.49, 68.23, and 45.59 mg L⁻¹, respectively. Cu was the most toxic metal to M. tuberculata, followed by Cd, Zn, Pb, Ni, Fe, Mn, and Al (Cu > Cd > Zn > Pb > Ni > Fe > Mn > Al). Metals bioconcentration in M. tuberculata increases with exposure to increasing concentrations and Cu has the highest accumulation (concentration factor) in the soft tissues. A comparison of LC₅₀ values for metals for this species with those for other freshwater gastropods reveals that M. tuberculata is equally sensitive to metals.

Matched MeSH terms: Metals/toxicity*
Toxicity of eight metals to Malaysian freshwater midge larvae Chironomus javanus (Diptera, Chironomidae)

Shuhaimi-Othman M, Yakub N, Umirah NS, Abas A

Toxicol Ind Health, 2011 Nov;27(10):879-86.
PMID: 21402654 DOI: 10.1177/0748233711399318

Fourth instars larvae of freshwater midge Chironomus javanus (Diptera, Chironomidae) were exposed for a 4-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al) and manganese (Mn) concentrations. Mortality was assessed and median lethal concentrations (LC(50)) were calculated. LC(50) increased with the decrease in mean exposure times, for all metals. LC(50)s for 96 hours for Cu, Cd, Zn, Pb, Ni, Fe, Al and Mn were 0.17, 0.06, 5.57, 0.72, 5.32, 0.62, 1.43 and 5.27 mg/L, respectively. Metals bioconcentration in C. javanus increases with exposure to increasing concentrations and Cd was the most toxic to C. javanus, followed by Cu, Fe, Pb, Al, Mn, Zn and Ni (Cd > Cu > Fe > Pb > Al > Mn > Zn > Ni). Comparison of LC(50) values for metals for this species with those for other freshwater midges reveals that C. javanus is equally or more sensitive to metals than most other tested dipteran.

Matched MeSH terms: Metals/pharmacokinetics; Metals/toxicity*
Toxicities and tolerances of Cd, Cu, Pb and Zn in a primary producer (Isochrysis galbana) and in a primary consumer (Perna viridis)

Yap CK, Ismail A, Omar H, Tan SG

Environ Int, 2004 Feb;29(8):1097-104.
PMID: 14680893

Studies on toxicities and tolerances of cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) in the brown alga Isochrysis galbana and in the green-lipped mussel Perna viridis were conducted by short-term bioassays using endpoints growth production and mortality, respectively. The 5-day EC(50) and 24-h LC(50) of these heavy metals were determined in the brown alga and mussel, respectively. The EC(50) values calculated for the alga were 0.74 mg/l for Cd, 0.91 mg/l for Cu, 1.40 mg/l for Pb and 0.60 mg/l for Zn. The LC(50) values for the mussels were 1.53 mg/l for Cd, 0.25 mg/l for Cu, 4.12 mg/l for Pb and 3.20 mg/l for Zn. These LC(50) values were within the concentration ranges as reported by other authors who used P. viridis as the test organism. Based on these EC(50) and LC(50) values, the alga was most sensitive to Zn, followed by Cd, Cu and Pb while the mussel was most sensitive to Cu, followed by Cd, Zn and Pb. Differences in the trophic levels, metal handling strategies, biology and ecology of the primary producer (brown alga) and the primary consumer (mussel) are believed to be the plausible causes for the different toxicities and tolerances of the metals studied.

Matched MeSH terms: Metals, Heavy/pharmacology*; Metals, Heavy/toxicity*
Toxic metals in Perna viridis mussel and surface seawater in Pasir Gudang coastal area, Malaysia, and its health implications

Mahat NA, Muktar NK, Ismail R, Abdul Razak FI, Abdul Wahab R, Abdul Keyon AS

Environ Sci Pollut Res Int, 2018 Oct;25(30):30224-30235.
PMID: 30155632 DOI: 10.1007/s11356-018-3033-8

Contamination of toxic metals in P. viridis mussels has been prevalently reported; hence, health risk assessment for consuming this aquaculture product as well as the surrounding surface seawater at its harvesting sites appears relevant. Since Kampung Pasir Puteh, Pasir Gudang is the major harvesting site in Malaysia, and because the last heavy metal assessment was done in 2009, its current status remains unclear. Herein, flame atomic absorption spectrometry and flow injection mercury/hydride system were used to determine the concentrations of Pb, Cd, Cu and total Hg in P. viridis mussels and surface seawater (January-March 2015), respectively. Significantly higher concentrations of these metals were found in P. viridis mussels (p

Matched MeSH terms: Metals, Heavy/adverse effects; Metals, Heavy/analysis*
Toxic heavy metal (Pb and Cd) content in tobacco cigarette brands in Selangor state, Peninsular Malaysia

Janaydeh M, Ismail A, Zulkifli SZ, Omar H

Environ Monit Assess, 2019 Sep 16;191(10):637.
PMID: 31529162 DOI: 10.1007/s10661-019-7755-y

Cadmium (Cd) and lead (Pb) are ubiquitous metals widely distributed in the environment, resulting in toxic health effects. This project aims to evaluate Pb and Cd as toxic elements in 15 different tobacco cigarette brands produced and/or sold in Selangor state, Peninsular Malaysia. The concentrations of Pb and Cd in all tobacco brands tested in this study were determined using the air-acetylene flame atomic absorption spectrophotometer (AAS). On average, the concentrations of Pb and Cd in different tobacco brand samples ranged from 3.05 and 0.80 μg/g dw, respectively. The results indicate that assessment mean values of Pb inhaled from smoking one packet of 20 cigarettes were in the range of 1.55-3.51 μg. Furthermore, the concentration of Cd inhaled per packet of cigarettes (20 sticks) is estimated to be 0.04-0.36 μg. However, there was a significant difference in the concentrations of Pb and Cd between the different brands of tobacco cigarettes, among cigarette prices (cheap versus expensive) of tobacco brands. In conclusion, cigarette smokers in Selangor, Malaysia, are heavily exposed to Pb and Cd, and such exposure could adversely affect their health in the long term. The impact of toxic heavy metals on smokers in this state would be an area for future research.

Matched MeSH terms: Metals, Heavy/analysis
Toxic Elements in Food: Occurrence, Binding, and Reduction Approaches

Hajeb P, Sloth JJ, Shakibazadeh S, Mahyudin NA, Afsah-Hejri L

Compr Rev Food Sci Food Saf, 2014 Jul;13(4):457-472.
PMID: 33412705 DOI: 10.1111/1541-4337.12068

Toxic elements such as mercury, arsenic, cadmium, and lead, sometimes called heavy metals, can diminish mental and central nervous system function; elicit damage to blood composition as well as the kidneys, lungs, and liver; and reduce energy levels. Food is considered one of the main routes of their entry into the human body. Numerous studies have been performed to examine the effects of common food processing procedures on the levels of toxic elements in food. While some studies have reported negative effects of processing, several have shown that processing practices may have a positive effect on the reduction of toxic elements in foodstuffs. A number of studies have also introduced protocols and suggested chemical agents that reduce the amount of toxic elements in the final food products. In this review, the reported methods employed for the reduction of toxic elements are discussed with particular emphasis on the chemical binding of both the organic and inorganic forms of each element in various foods. The molecular groups and the ligands by which the food products bind with the metals and the types of these reactions are also presented.

Matched MeSH terms: Metals, Heavy
Fulltext Three dimensional metal/N-doped nanoplate carbon catalysts for oxygen reduction, the reason for using a layered nanoreactor

Yeganeh Ghotbi M, Javanmard A, Soleimani H

Sci Rep, 2018 02 21;8(1):3404.
PMID: 29467510 DOI: 10.1038/s41598-018-21782-3

A layered nanoreactor (zinc hydroxide gallate/nitrate nanohybrid) has been designed as a nano-vessel to confine the gallate/nitrate reaction inside zinc hydroxide layers for production of metal/nitrogen-doped carbon catalysts. Metals (Fe2+, Co2+ and Ni2+) doped and bare zinc hydroxide nitrates (ZHN) were synthesized as the α-phase hydroxide hosts. By an incomplete ion-exchange process, nitrate anions between the layers of the hosts were then partially replaced by the gallate anions to produce the layered nanoreactors. Under heat-treatment, the reaction between the remaining un-exchanged nitrate anions and the organic moiety inside the basal spacing of each nanohybrid plate resulted in obtaining highly porous 3D metal/nitrogen-doped carbon nanosheets. These catalysts were then used as extremely efficient electrocatalysts for catalyzing oxygen reduction reaction (ORR). This study is intended to show the way to get maximum electrocatalytic activity of the metal/N-doped carbon catalysts toward the ORR. This exceptionally high ORR performance originates from the increased available surface, the best pore size range and the uniform distribution of the active sites in the produced catalysts, all provided by the use of new idea of the layered nanoreactor.

Matched MeSH terms: Metals
Three decades of sea water abstraction by Kapar power plant (Malaysia): What impacts on tropical zooplankton community?

Chew LL, Chong VC, Wong RCS, Lehette P, Ng CC, Loh KH

Mar Pollut Bull, 2015 Dec 15;101(1):69-84.
PMID: 26581817 DOI: 10.1016/j.marpolbul.2015.11.022

Zooplankton samples collected before (1985-86) and after (2013-14) the establishment of Kapar power station (KPS) were examined to test the hypothesis that increased sea surface temperature (SST) and other water quality changes have altered the zooplankton community structure. Elevated SST and reduced pH were detected between before and after impact pairs, with the greatest impact at the station closest to KPS. Present PAHs and heavy metal concentrations are unlikely causal factors. Water parameter changes did not affect diversity but community structure of the zooplankton. Tolerant small crustaceans, salps and larvaceans likely benefited from elevated temperature, reduced pH and shift to a more significant microbial loop exacerbated by eutrophication, while large crustaceans were more vulnerable to such changes. It is predicted that any further rise in SST will remove more large-bodied crustacean zooplankton, the preferred food for fish larvae and other meroplankton, with grave consequences to fishery production.

Matched MeSH terms: Metals, Heavy/analysis
Thin strut bare metal stents in patients with atrial fibrillation: Is there still a need for BMS?

Leschke M, Waliszewski M, Pons M, Champin S, Nait Saidi L, Mok Heang T, et al.

Catheter Cardiovasc Interv, 2016 Sep;88(3):358-66.
PMID: 26650913 DOI: 10.1002/ccd.26261

OBJECTIVES: This observational study assessed the 9-month clinical outcomes in an « all comers » population with a focus on patients with atrial fibrillation (AF) after thin strut bare metal stenting.
BACKGROUND: Drug eluting stent (DES) implantation is the treatment of choice for coronary artery disease (CAD) leaving only marginal indications for the use of bare metal stents (BMS). However, selected treatment populations with DES contraindications such as patients who cannot sustain 6-12 months of dual antiplatelet therapy (DAPT) remain candidates for BMS implantations.
METHODS: Thin strut bare metal stenting in a priori defined subgroups were investigated in a non-randomized, international, multicenter «all comers» observational study. Primary endpoint was the 9-month TLR rate whereas secondary endpoints included the 9-month MACE and procedural success rates.
RESULTS: A total of 783 patients of whom 98 patients had AF underwent BMS implantation. Patient age was 70.4 ± 12.8 years. Cardiovascular risk factors in the overall population were male gender (78.2%, 612/783), diabetes (25.2%, 197/783), hypertension (64.1%, 502/783), cardiogenic shock (4.9%, 38/783) and end stage renal disease (4.9%, 38/783). In-hospital MACE was 4.1% (30/783) in the overall population. The 9-month TLR rate was 4.5% (29/645) in the non-AF group and 3.3% (3/90) in the AF group (P = 0.613). At 9 months, the MACE rate in the AF-group and non-AF group was not significantly different either (10.7%, 69/645 vs. 6.7%, 6/90; P = 0.237). Accumulated stroke rates were 0.3% (2/645) in the non-AF subgroup at baseline and 1.1% (1/90) in the AF subgroup (P = 0.264).
CONCLUSION: Bare metal stenting in AF patients delivered acceptably low TLR and MACE rates while having the benefit of a significantly shorter DAPT duration in a DES dominated clinical practice. © 2015 Wiley Periodicals, Inc.

Matched MeSH terms: Metals*
Thermoluminescence responses of photon- and electron-irradiated lithium potassium borate co-doped with Cu+Mg or Ti+Mg

Alajerami YS, Hashim S, Ramli AT, Saleh MA, Saripan MI, Alzimami K, et al.

Appl Radiat Isot, 2013 Aug;78:21-5.
PMID: 23644162 DOI: 10.1016/j.apradiso.2013.03.095

New glasses Li2CO3-K2CO3-H3BO3 (LKB) co-doped with CuO and MgO, or with TiO2 and MgO, were synthesized by the chemical quenching technique. The thermoluminescence (TL) responses of LKB:Cu,Mg and LKB:Ti,Mg irradiated with 6 MV photons or 6 MeV electrons were compared in the dose range 0.5-4.0 Gy. The standard commercial dosimeter LiF:Mg,Ti (TLD-100) was used to calibrate the TL reader and as a reference in comparison of the TL properties of the new materials. The dependence of the responses of the new materials on (60)Co dose is linear in the range of 1-1000 Gy. The TL yields of both of the co-doped glasses and TLD-100 are greater for electron irradiation than for photon irradiation. The TL sensitivity of LKB:Ti,Mg is 1.3 times higher than the sensitivity of LKB:Cu,Mg and 12 times less than the sensitivity of TLD-100. The new TL dosimetric materials have low effective atomic numbers, good linearity of the dose responses, excellent signal reproducibility, and a simple glow curve structure. This combination of properties makes them suitable for radiation dosimetry.

Matched MeSH terms: Metals/radiation effects*; Metals/chemistry*
Fulltext Thermo-mechanical contact problems and elastic behaviour of single and double sides functionally graded brake disks with temperature-dependent material properties

Bayat M, Alarifi IM, Khalili AA, El-Bagory TMAA, Nguyen HM, Asadi A

Sci Rep, 2019 Oct 25;9(1):15317.
PMID: 31653877 DOI: 10.1038/s41598-019-51450-z

A thermo-elastic contact problem of functionally graded materials (FGMs) rotating brake disk with different pure brake pad areas under temperature dependent material properties is solved by Finite Element Method (FEM). The properties of brake disk change gradually from metal to ceramic by power-law distribution along the radial direction from the inner to the outer surface. Areas of the pure pad are changing while the vertical force is constant. The ratio of brake pad thickness to FGMs brake disk thickness is assumed 0.66. Two sources of thermal loads are considered: (1) Heat generation between the pad and brake disk due to contact friction, and (2) External thermal load due to a constant temperature at inner and outer surfaces. Mechanical responses of FGMs disk are compared with several pad contact areas. The results for temperature-dependent and temperature-independent material properties are investigated and presented. The results show that the absolute value of the shear stress in temperature-dependent material can be greater than that for temperature-independent material. The radial stress for some specific grading index (n = 1.5) is compressive near the inner surface for double contact while it is tensile for a single contact. It is concluded that the radial strain for some specific value of grading index (n = 1) is lower than other FGMs and pure double side contact brake disks.

Matched MeSH terms: Metals

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