Displaying publications 21 - 40 of 385 in total

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  1. Is metal nanofluid reliable as heat carrier?
    Nine MJ, Chung H, Tanshen MR, Osman NA, Jeong H
    J Hazard Mater, 2014 May 30;273:183-91.
    PMID: 24735805 DOI: 10.1016/j.jhazmat.2014.03.055
    A pre- and post experimental analysis of copper-water and silver-water nanofluids are conducted to investigate minimal changes in quality of nanofluids before and after an effective heat transfer. A single loop oscillating heat pipe (OHP) having inner diameter of 2.4mm is charged with aforementioned nanofluids at 60% filling ratio for end to end heat transfer. Post experimental analysis of both nanofluids raises questions to the physical, chemical and thermal stability of such suspension for hazardless uses in the field of heat transfer. The color, deposition, dispersibility, propensity to be oxidized, disintegration, agglomeration and thermal conductivity of metal nanofluids are found to be strictly affected by heat transfer process and vice versa. Such degradation in quality of basic properties of metal nanofluids implies its challenges in practical application even for short-term heat transfer operations at oxidative environment as nano-sized metal particles are chemically more unstable than its bulk material. The use of the solid/liquid suspension containing metal nanoparticles in any heat exchanger as heat carrier might be detrimental to the whole system.
    Matched MeSH terms: Copper*
  2. Hexane-extracted spent bleaching earth as a sorbent for copper in aqueous solution
    Low KS, Lee CK, Lee TS
    Bull Environ Contam Toxicol, 1996 Mar;56(3):405-12.
    PMID: 8825962
    Matched MeSH terms: Copper/metabolism*
  3. An analysis of the personal reasons for discontinuing IUD use
    Petta CA, Amatya R, Farr G, Chi I
    Contraception, 1994 Oct;50(4):339-47.
    PMID: 7813222
    The objective of this study was to evaluate possible factors associated with discontinuing use of TCu 380A IUDs due to personal reasons among 2748 users. Overall, a total of 88 subjects discontinued using the TCu 380A IUD within 12 months postinsertion for personal reasons. The most common reasons were planned pregnancy (32%) and husband or family opinion against IUD use (26%). The gross cumulative 12-month life table discontinuation rate for all personal reasons was 4.0 per 100 women. Having no education and/or living in a rural area were the sociodemographic characteristics associated with an increased risk of discontinuation for personal reasons. Effective and regular counseling about IUD use, especially among illiterate women, may help prevent IUD discontinuations related to personal reasons.
    Matched MeSH terms: Intrauterine Devices, Copper*
  4. A longitudinal study of serum iron indices and haemoglobin concentration following copper-IUD insertion
    Goh TH, Hariharan M, Tan CH
    Contraception, 1980 Oct;22(4):389-95.
    PMID: 7449387
    The increase in menstrual blood loss associated with copper-bearing IUDs may cause or aggravate pre-existing anaemia. In order to evaluate this risk, 84 Malaysian women wearing copper-IUDs were studied longitudinally by means of serial measurements of blood haemoglobin concentration (Hb), serum iron (S/Fe) and transferrin saturation (T/S). The initial Hb was under 12 gm% in 33.7% of patients. The mean Hb showed no significant change up to 12 months while S/Fe fell significantly at the end of this time; the T/S was significantly reduced as early as 6 months post-insertion. There is a significant risk of anaemia following copper-IUD insertion, particularly with long-term usage. Progestogen-releasing IUDs may offer the most feasible solution to this problem in our local context since oral medication with iron or drugs to reduce menstrual blood loss is not practicable.
    Matched MeSH terms: Intrauterine Devices, Copper*
  5. Fulltext Thermal Charging Optimization of a Wavy-Shaped Nano-Enhanced Thermal Storage Unit
    Ghalambaz M, Mehryan SAM, Hajjar A, Shdaifat MYA, Younis O, Talebizadehsardari P, et al.
    Molecules, 2021 Mar 09;26(5).
    PMID: 33803488 DOI: 10.3390/molecules26051496
    A wavy shape was used to enhance the thermal heat transfer in a shell-tube latent heat thermal energy storage (LHTES) unit. The thermal storage unit was filled with CuO-coconut oil nano-enhanced phase change material (NePCM). The enthalpy-porosity approach was employed to model the phase change heat transfer in the presence of natural convection effects in the molten NePCM. The finite element method was applied to integrate the governing equations for fluid motion and phase change heat transfer. The impact of wave amplitude and wave number of the heated tube, as well as the volume concertation of nanoparticles on the full-charging time of the LHTES unit, was addressed. The Taguchi optimization method was used to find an optimum design of the LHTES unit. The results showed that an increase in the volume fraction of nanoparticles reduces the charging time. Moreover, the waviness of the tube resists the natural convection flow circulation in the phase change domain and could increase the charging time.
    Matched MeSH terms: Copper/chemistry*
  6. Novel alkaline-reduced cuprous oxide/graphene nanocomposites for non-enzymatic amperometric glucose sensor application
    Yazid SNAM, Isa IM, Hashim N
    Mater Sci Eng C Mater Biol Appl, 2016 Nov 01;68:465-473.
    PMID: 27524043 DOI: 10.1016/j.msec.2016.06.006
    This paper presents the fabrication of a highly sensitive and selective glucose sensor based on cuprous oxide/graphene nanocomposites-modified glassy carbon electrode (Cu2O/graphene/GCE). The Cu2O/graphene nanocomposites were synthesized based on a simple and straightforward chemical reduction process in alkaline aqueous solution using sodium carbonate as reductant. The size and shape of Cu2O nanoparticles on graphene sheets can be controlled by changing the amount of graphene oxide added during reaction. The electrochemical properties of Cu2O/graphene/GCE in 0.1M phosphate buffer solution were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. It was found that the pH, concentration of supporting electrolyte, and scan rate had very crucial effect on the sensitivity of prepared sensor towards glucose oxidation. At an applied potential of +0.50V, the Cu2O/graphene/GCE presented a high sensitivity of 1330.05μAmM(-1)cm(-2) and fast response (within 3s). The amperometric non-enzymatic glucose sensor developed had a linear relationship from 0.01mM to 3.0mM glucose and detection limit of 0.36μM. In the presence of ascorbic acid, uric acid, dopamine, chloride and citrate ion and other carbohydrates, the interferences were negligible. The proposed sensor was successfully applied for the determination of glucose concentration in real human blood samples.
    Matched MeSH terms: Copper/chemistry*
  7. Fulltext A one dimensional PAGE studies on Puntius javanicus liver proteome affected by copper toxicity
    Mohd Khalizan Sabullah, Azlan Jualang Gansau, Mohd Rosni Sulaiman, Fisal Ahmad
    Bioremediation Science and Technology Research, 2015;3(2):26-29.
    MyJurnal
    Observations on the effects of copper on the liver proteome of Puntius javanicus based on the
    one dimensional PAGE was carried out. The liver was dissected from each fish, which was
    separately treated with different concentrations of copper sulfate ranging from 0.1 to 5.0 mg/L.
    The livers were extracted and one dimensional PAGE was performed under nonreducing
    (native) and reducing (SDS)-PAGE. Several bands were resolved in the native PAGE with
    probable candidates for the effect of copper observed showing an increased in the expression
    and downregulation strongly associated with increasing copper concentrations. This study
    showed that high concentrations of copper significantly alters P. javanicus liver at the proteome
    level, and preliminary screening based on one dimensional PAGE is considered rapid and
    simple to assess the toxicity effect of copper before more advanced and extensive assesment
    with a second dimensional PAGE is carried out.
    Matched MeSH terms: Copper; Copper Sulfate
  8. Bio-waste corn-cob cellulose supported poly(hydroxamic acid) copper complex for Huisgen reaction: Waste to wealth approach
    Mandal BH, Rahman ML, Yusoff MM, Chong KF, Sarkar SM
    Carbohydr Polym, 2017 Jan 20;156:175-181.
    PMID: 27842811 DOI: 10.1016/j.carbpol.2016.09.021
    Corn-cob cellulose supported poly(hydroxamic acid) Cu(II) complex was prepared by the surface modification of waste corn-cob cellulose through graft copolymerization and subsequent hydroximation. The complex was characterized by IR, UV, FESEM, TEM, XPS, EDX and ICP-AES analyses. The complex has been found to be an efficient catalyst for 1,3-dipolar Huisgen cycloaddition (CuAAC) of aryl/alkyl azides with a variety of alkynes as well as one-pot three-components reaction in the presence of sodium ascorbate to give the corresponding cycloaddition products in up to 96% yield and high turn over number (TON 18,600) and turn over frequency (TOF 930h-1) were achieved. The complex was easy to recover from the reaction mixture and reused six times without significant loss of its catalytic activity.
    Matched MeSH terms: Copper/chemistry*
  9. Global patterns and driving factors of plant litter iron, manganese, zinc, and copper concentrations
    Peng Y, Fornara DA, Wu Q, Heděnec P, Yuan J, Yuan C, et al.
    Sci Total Environ, 2023 Jan 20;857(Pt 3):159686.
    PMID: 36302428 DOI: 10.1016/j.scitotenv.2022.159686
    Plant litter decomposition is not only the major source of soil carbon and macronutrients, but also an important process for the biogeochemical cycling of trace elements such as iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu). The concentrations of plant litter trace elements can influence litter decomposition and element cycling across the plant and soil systems. Yet, a global perspective of the patterns and driving factors of trace elements in plant litter is missing. To bridge this knowledge gap, we quantitatively assessed the concentrations of four common trace elements, namely Fe, Mn, Zn, and Cu, of freshly fallen plant litter with 1411 observations extracted from 175 publications across the globe. Results showed that (1) the median of the average concentrations of litter Fe, Mn, Zn, and Cu were 0.200, 0.555, 0.032, and 0.006 g/kg, respectively, across litter types; (2) litter concentrations of Fe, Zn, and Cu were generally stable regardless of variations in multiple biotic and abiotic factors (e.g., plant taxonomy, climate, and soil properties); and (3) litter Mn concentration was more sensitive to environmental conditions and influenced by multiple factors, but mycorrhizal association and soil pH and nitrogen concentration were the most important ones. Overall, our study provides a clear global picture of plant litter Fe, Mn, Zn, and Cu concentrations and their driving factors, which is important for improving our understanding on their biogeochemical cycling along with litter decomposition processes.
    Matched MeSH terms: Copper/analysis
  10. Enhanced adsorption selectivity of Au(III) over Cu(II) from acidic chloride solutions by chitosan/palm kernel fatty acid distillate/magnetite nanocomposites
    Chang SH, Jampang AOA
    Int J Biol Macromol, 2023 Dec 01;252:126491.
    PMID: 37625756 DOI: 10.1016/j.ijbiomac.2023.126491
    This work aimed to develop a modified chitosan adsorbent with enhanced adsorption selectivity for Au(III) over Cu(II) from acidic chloride solutions using low-cost and green raw materials. Various adsorbents, i.e., chitosan powder, chitosan microbeads, chitosan/palm kernel fatty acid distillate (PKFAD) microcomposites, magnetite nanoparticles, and chitosan/PKFAD/magnetite nanocomposites (CPMNs), were first evaluated for their ability to adsorb Au(III) and Cu(II) from single- and binary-metal solutions across different pH levels, followed by parametric analysis of Au(III) and Cu(II) adsorption from binary- and multi-metal solutions onto CPMNs, Au(III) desorption from Au(III)-loaded CPMNs, and reusability of CPMNs. Finally, Au(III)-loaded CPMNs were characterized with SEM-EDX, XRD, FTIR, and XPS to confirm the proposed adsorption mechanisms. Among all the adsorbents studied, CPMNs exhibited outstanding performance in adsorbing Au(III) from an equimolar binary Au(III)-Cu(II) solution, achieving the highest equilibrium adsorption capacity of 0.479 mmol/g (94.4 mg/g) without reaching saturation. Under optimal adsorption conditions of pH 3, 1 g/L CPMN dosage, and 90 min contact time, CPMNs adsorbed 96 % of Au(III) with a selectivity over Cu(II) exceeding 99 %. CPMNs demonstrated excellent reusability, maintaining over 80 % adsorption and desorption efficiencies for 5 cycles. The proposed adsorption mechanisms of CPMNs for Au(III) encompass electrostatic attraction, hydrogen bonding, solvation, and reduction.
    Matched MeSH terms: Copper/chemistry
  11. Structural Basis for the Effects of Phenylalanine on Tuning the Reduction Potential of Type 1 Copper in Azurin
    Liu Y, Marshall NM, Yu SS, Kim W, Gao YG, Robinson H, et al.
    Inorg Chem, 2023 Jul 24;62(29):11618-11625.
    PMID: 37424080 DOI: 10.1021/acs.inorgchem.3c01365
    In order to investigate the effects of the secondary coordination sphere in fine-tuning redox potentials (E°') of type 1 blue copper (T1Cu) in cupredoxins, we have introduced M13F, M44F, and G116F mutations both individually and in combination in the secondary coordination sphere of the T1Cu center of azurin (Az) from Pseudomonas aeruginosa. These variants were found to differentially influence the E°' of T1Cu, with M13F Az decreasing E°', M44F Az increasing E°', and G116F Az showing a negligible effect. In addition, combining the M13F and M44F mutations increases E°' by 26 mV relative to WT-Az, which is very close to the combined effect of E°' by each mutation. Furthermore, combining G116F with either M13F or M44F mutation resulted in negative and positive cooperative effects, respectively. Crystal structures of M13F/M44F-Az, M13F/G116F-Az, and M44F/G116F-Az combined with that of G116F-Az reveal these changes arise from steric effects and fine-tuning of hydrogen bond networks around the copper-binding His117 residue. The insights gained from this study would provide another step toward the development of redox-active proteins with tunable redox properties for many biological and biotechnological applications.
    Matched MeSH terms: Copper/chemistry
  12. Fulltext Improvement in sensitivity of an inductive oil palm fruit sensor
    Misron N, Harun NH, Lee YK, Sidek RM, Aris I, Wakiwaka H, et al.
    Sensors (Basel), 2014;14(2):2431-48.
    PMID: 24496313 DOI: 10.3390/s140202431
    Among palm oil millers, the ripeness of oil palm Fresh Fruit Bunch (FFB) is determined through visual inspection. To increase the productivity of the millers, many researchers have proposed with a new detection method to replace the conventional one. The sensitivity of such a sensor plays a crucial role in determining the effectiveness of the method. In our preliminary study a novel oil palm fruit sensor to detect the maturity of oil palm fruit bunches is proposed. The design of the proposed air coil sensor based on an inductive sensor is further investigated to improve its sensitivity. This paper investigates the results pertaining to the effects of the air coil structure of an oil palm fruit sensor, taking consideration of the used copper wire diameter ranging from 0.10 mm to 0.18 mm with 60 turns. The flat-type shape of air coil was used on twenty samples of fruitlets from two categories, namely ripe and unripe. Samples are tested with frequencies ranging from 20 Hz to 120 MHz. The sensitivity of the sensor between air to fruitlet samples increases as the coil diameter increases. As for the sensitivity differences between ripe and unripe samples, the 5 mm air coil length with the 0.12 mm coil diameter provides the highest percentage difference between samples and it is amongst the highest deviation value between samples. The result from this study is important to improve the sensitivity of the inductive oil palm fruit sensor mainly with regards to the design of the air coil structure. The efficiency of the sensor to determine the maturity of the oil palm FFB and the ripening process of the fruitlet could further be enhanced.
    Matched MeSH terms: Copper
  13. Fulltext Piezoresistive effects in controllable defective HFTCVD graphene-based flexible pressure sensor
    Mohammad Haniff MA, Muhammad Hafiz S, Wahid KA, Endut Z, Wah Lee H, Bien DC, et al.
    Sci Rep, 2015;5:14751.
    PMID: 26423893 DOI: 10.1038/srep14751
    In this work, the piezoresistive effects of defective graphene used on a flexible pressure sensor are demonstrated. The graphene used was deposited at substrate temperatures of 750, 850 and 1000 °C using the hot-filament thermal chemical vapor deposition method in which the resultant graphene had different defect densities. Incorporation of the graphene as the sensing materials in sensor device showed that a linear variation in the resistance change with the applied gas pressure was obtained in the range of 0 to 50 kPa. The deposition temperature of the graphene deposited on copper foil using this technique was shown to be capable of tuning the sensitivity of the flexible graphene-based pressure sensor. We found that the sensor performance is strongly dominated by the defect density in the graphene, where graphene with the highest defect density deposited at 750 °C exhibited an almost four-fold sensitivity as compared to that deposited at 1000 °C. This effect is believed to have been contributed by the scattering of charge carriers in the graphene networks through various forms such as from the defects in the graphene lattice itself, tunneling between graphene islands, and tunneling between defect-like structures.
    Matched MeSH terms: Copper
  14. Fulltext Analysis of machining pit by using electrical discharge machine die sinking
    Md Razak Daud, Wan Nor Shela Ezwane Wan Jusoh, Syahrullail Samion
    Journal of Engineering and Science Research, 2018;2(6):63-67.
    MyJurnal
    This study investigates metal removal rate (MRR) of the biomaterial by using discharge machine Neuar CNC A50 Electrical Discharge Machine Die Sinking (EDM DS). The purpose of this study is to compare machining curvature cup for material SKD 11 and stainless steel with shape curvature cup acetabular. The result showed that electrode wear is higher when high current is applied. For each applied current 0.5A and 3.0A could result electrode wear of 0.236 mm, 0.246 mm and 0.269 mm respectively. Mean time of complete discharged for each pit with 0.3mm depth with supply 0. 5A is 6.51 minutes; 1. 5A is 3.54 minutes and 3A is 1.52 minutes. The biggest mean parameter of the pit is 0.356 mm, with 3A of current is applied. From this study, it can be concluded that low current set may give lower electrode copper wear. The experiment will help a researcher to discharge biomaterial types of metal with small size of copper electrode use of EDM DS Neuar for discharge multi hole or micro pit.
    Matched MeSH terms: Copper
  15. Production of high quality biodiesel from novel non-edible Raphnus raphanistrum L. seed oil using copper modified montmorillonite clay catalyst
    Munir M, Ahmad M, Rehan M, Saeed M, Lam SS, Nizami AS, et al.
    Environ Res, 2021 02;193:110398.
    PMID: 33127396 DOI: 10.1016/j.envres.2020.110398
    This study focused on producing high quality and yield of biodiesel from novel non-edible seed oil of abundantly available wild Raphnus raphanistrum L. using an efficient, recyclable and eco-friendly copper modified montmorillonite (MMT) clay catalyst. The maximum biodiesel yield of 83% was obtained by base catalyzed transesterification process under optimum operating conditions of methanol to oil ratio of 15:1, reaction temperature of 150 °C, reaction time of 5 h and catalyst loading of 3.5%. The synthesized catalyst and biodiesel were characterized for their structural features and chemical compositions using various state-of-the-art techniques, including x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, Fourier transform infrared spectroscopy, nuclear magnetic resonance (1H, 13C) and gas chromatography-mass spectroscopy. The fuel properties of the biodiesel were estimated including kinematic viscosity (4.36 cSt), density (0.8312 kg/L), flash point (72 °C), acid value (0.172 mgKOH/g) and sulphur content (0.0002 wt.%). These properties were compared and found in good agreement with the International Biodiesel Standards of American (ASTM-951, 6751), European Committee (EN-14214) and China GB/T 20828 (2007). The catalyst was re-used in five consecutive transesterification reactions without losing much catalytic efficiency. Overall, non-edible Raphnus raphanistrum L.. seed oil and Cu doped MMT clay catalyst appeared to be highly active, stable, and cheap contenders for future biofuel industry. However, detailed life cycle assessment (LCA) studies of Raphnus raphanistrum L. seed oil biodiesel are highly recommended to assess the technical, ecological, social and economic challenges.
    Matched MeSH terms: Copper
  16. Synthesis and modelling of the mechanical properties of Ag, Au and Cu nanowires
    Lah NAC, Trigueros S
    Sci Technol Adv Mater, 2019;20(1):225-261.
    PMID: 30956731 DOI: 10.1080/14686996.2019.1585145
    The recent interest to nanotechnology aims not only at device miniaturisation, but also at understanding the effects of quantised structure in materials of reduced dimensions, which exhibit different properties from their bulk counterparts. In particular, quantised metal nanowires made of silver, gold or copper have attracted much attention owing to their unique intrinsic and extrinsic length-dependent mechanical properties. Here we review the current state of art and developments in these nanowires from synthesis to mechanical properties, which make them leading contenders for next-generation nanoelectromechanical systems. We also present theories of interatomic interaction in metallic nanowires, as well as challenges in their synthesis and simulation.
    Matched MeSH terms: Copper
  17. Biogasoline production from linoleic acid via catalytic cracking over nickel and copper-doped ZSM-5 catalysts
    Gurdeep Singh HK, Yusup S, Quitain AT, Abdullah B, Ameen M, Sasaki M, et al.
    Environ Res, 2020 07;186:109616.
    PMID: 32668556 DOI: 10.1016/j.envres.2020.109616
    Catalytic cracking of vegetable oil mainly processed over zeolites, and among all the zeolites particularly HZMS-5 has been investigated on wide range for renewable and clean gasoline production from various plant oils. Despite the fact that HZSM-5 offers a higher conversion degree and boost aromatics yield, the isomerate yield reduces due to high cracking activity and shape selectivity of HZSM-5. Hence, to overcome these problems, in this study the transition metals, such as nickel and copper doped over HZSM-5 were tested for its efficiencies to improve the isoparaffin compounds. The catalysts were screened with linoleic acid in a catalytic cracking reaction conducted at 450 ᵒC for 90 min in an atmospheric condition in batch reactor. Then, the gasoline composition of the organic liquid product (OLP) was analysed in terms of paraffin, isoparaffin, olefin, naphthenes and aromatics (PIONA). The results showed that Cu/ZSM-5 produced the highest liquid yield of 79.1%, at the same time reduced the production of gas and coke to 18.8% and 0.7%. Furthermore, the desired isoparaffin composition in biogasoline increased from 1.6% to 6.8% and at the same time reduced the oxygenated and aromatic compounds to 15.4% and 59.7%, respectively. The linoleic acid as model compound of rubber seed oil, in the catalytic cracking reaction provides a clearer understanding of the process. Besides, the water gas shift (WGS) reaction in catalytic cracking reaction provides insitu hydrogen production to saturate the branched olefin into the desired isoparaffin and the aromatics into naphthenes.
    Matched MeSH terms: Copper
  18. Preparation of novel nanostructured WO3/CuMnO2 p-n heterojunction nanocomposite for photoelectrochemical detection of nitrofurazone
    Velmurugan S, C-K Yang T, Ching Juan J, Chen JN
    J Colloid Interface Sci, 2021 Aug 15;596:108-118.
    PMID: 33838324 DOI: 10.1016/j.jcis.2021.03.083
    Herein this research, a visible light active tungsten oxide/copper manganate (WO3/CuMnO2) p-n heterojunction nanocomposite was prepared and has been applied for a signal on photoelectrochemical sensing of antibiotic nitrofurazone (NFZ). Firstly, the n-WO3 nanotiles were synthesized from the cetrimonium bromide (CTAB) assisted hydrothermal method and the p-CuMnO2 nanoparticles were synthesized by using the ultrasound-assisted hydrothermal method. The photoelectrochemical NFZ sensing performance of WO3/CuMnO2 nanocomposite was 1.9 times higher than that of as-synthesized pure WO3 nanotiles. The resulting higher photoelectrochemical performance of the nanocomposite is due to more visible light absorption ability and synergy from p-n heterojunction formation. The designed WO3/CuMnO2 nanocomposite sensor gives satisfactory photocurrent signals for the detection of NFZ in the range of 0.015-32 μM with the detection limit (LOD) of 1.19 nM. The practical applicability of the nanocomposite sensor was monitored in pork liver and tap water samples.
    Matched MeSH terms: Copper
  19. Fulltext Frequency distribution of foliar nickel is bimodal in the ultramafic flora of Kinabalu Park (Sabah, Malaysia)
    van der Ent A, Echevarria G, Nkrumah PN, Erskine PD
    Ann Bot, 2020 10 30;126(6):1017-1027.
    PMID: 32597938 DOI: 10.1093/aob/mcaa119
    BACKGROUND AND AIMS: The aim of this study was to test the frequency distributions of foliar elements from a large dataset from Kinabalu Park (Sabah, Malaysia) for departure from unimodality, indicative of a distinct ecophysiological response associated with hyperaccumulation.

    METHODS: We collected foliar samples (n = 1533) comprising 90 families, 198 genera and 495 plant species from ultramafic soils, further foliar samples (n = 177) comprising 45 families, 80 genera and 120 species from non-ultramafic soils and corresponding soil samples (n = 393 from ultramafic soils and n = 66 from non-ultramafic soils) from Kinabalu Park (Sabah, Malaysia). The data were geographically (Kinabalu Park) and edaphically (ultramafic soils) constrained. The inclusion of a relatively high proportion (approx. 14 %) of samples from hyperaccumulator species [with foliar concentrations of aluminium and nickel (Ni) >1000 μg g-1, cobalt, copper, chromium and zinc >300 μg g-1 or manganese (Mn) >10 mg g-1] allowed for hypothesis testing.

    KEY RESULTS: Frequency distribution graphs for most elements [calcium (Ca), magnesium (Mg) and phosphorus (P)] were unimodal, although some were skewed left (Mg and Mn). The Ni frequency distribution was bimodal and the separation point for the two modes was between 250 and 850 μg g-1.

    CONCLUSIONS: Accounting for statistical probability, the established empirical threshold value (>1000 μg g-1) remains appropriate. The two discrete modes for Ni indicate ecophysiologically distinct behaviour in plants growing in similar soils. This response is in contrast to Mn, which forms the tail of a continuous (approximately log-normal) distribution, suggestive of an extension of normal physiological processes.

    Matched MeSH terms: Copper
  20. Kayser-Fleischer rings and Wilson's disease
    Low QJ, Siaw C, Lee RA, Cheo SW
    QJM, 2020 Sep 01;113(9):693-694.
    PMID: 31917404 DOI: 10.1093/qjmed/hcaa005
    Matched MeSH terms: Copper
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