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https://www.readbyqxmd.com/read/28110351/determining-lead-cadmium-and-mercury-in-cosmetics-using-sweeping-via-dynamic-chelation-by-capillary-electrophoresis
#1
Kuan-Ling Chen, Shiuh-Jen Jiang, Yen-Ling Chen
International limits have been established for metal impurities in cosmetics to prevent overexposure to heavy metal ions. Sweeping via dynamic chelation was developed using capillary electrophoresis to analyze lead (Pb), cadmium (Cd) and mercury (Hg) impurities in cosmetics. The sweeping via dynamic chelation mechanism involves a large volume of metal ions being swept by a small quantity of chelating agents that were electrokinetically injected into the capillary to chelate metal ions and increase the detection sensitivity...
January 21, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28110178/tem-sample-preparation-by-femtosecond-laser-machining-and-ion-milling-for-high-rate-tem-straining-experiments
#2
Thomas Voisin, Michael D Grapes, Yong Zhang, Nicholas Lorenzo, Jonathan Ligda, Brian Schuster, Timothy P Weihs
To model mechanical properties of metals at high strain rates, it is important to visualize and understand their deformation at the nanoscale. Unlike post mortem Transmission Electron Microscopy (TEM), which allows one to analyze defects within samples before or after deformation, in situ TEM is a powerful tool that enables imaging and recording of deformation and the associated defect motion during mechanical loading. Unfortunately, all current in situ TEM mechanical testing techniques are limited to quasi-static strain rates...
December 5, 2016: Ultramicroscopy
https://www.readbyqxmd.com/read/28110045/antioxidative-systems-metal-ion-homeostasis-and-cadmium-distribution-in-iris-lactea-exposed-to-cadmium-stress
#3
Qiang Guo, Lin Meng, Ya-Nan Zhang, Pei-Chun Mao, Xiao-Xia Tian, Shan-Shan Li, Lin Zhang
Iris lactea is a perennial halophyte and is tolerant to Cd. However, the mechanisms underlying this Cd tolerance are still poorly understood. In this study, morphological, physiological and biochemical responses of I. lactea to a 21 d exposure to different concentrations of Cd (0-150mgL(-1)) were investigated. I. lactea plants showed no toxicity symptoms except for a small reduction in growth at 100 and 150mgL(-1) Cd, along with the enhancement of H2O2 and MDA content in comparison to the control. The activities of SOD and POD were significantly enhanced and Ca accumulated with increasing Cd concentrations...
January 19, 2017: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/28110009/influence-of-ph-on-heavy-metal-speciation-and-removal-from-wastewater-using-micellar-enhanced-ultrafiltration
#4
Jinhui Huang, Fang Yuan, Guangming Zeng, Xue Li, Yanling Gu, Lixiu Shi, Wenchu Liu, Yahui Shi
pH plays an important role in heavy metal removal during micellar-enhanced ultrafiltration (MEUF). In the present work, the influence of pH on heavy metal speciation and removal from wastewater by MEUF was investigated using an anionic surfactant (sodium dodecyl sulfate, SDS) and a hydrophilic membrane (polyether sulfone). Experiments were performed with pH values in the range of 1-12. Metal ion removal efficiency (R) was used to assess the effects of the MEUF process. Results showed that better removal rate of copper and cadmium was achieved at high pH values (pH > 3) with SDS feed concentration of 8 mM, while the optimal pH range was 3-10 for zinc and lead...
December 28, 2016: Chemosphere
https://www.readbyqxmd.com/read/28109965/a-novel-acidic-ph-fluorescent-probe-based-on-a-benzothiazole-derivative
#5
Qiujuan Ma, Xian Li, Suxiang Feng, Beibei Liang, Tiqiang Zhou, Min Xu, Zhuoyi Ma
A novel acidic pH fluorescent probe 1 based on a benzothiazole derivative has been designed, synthesized and developed. The linear response range covers the acidic pH range from 3.44 to 6.46, which is valuable for pH researches in acidic environment. The evaluated pKa value of the probe 1 is 4.23. The fluorescence enhancement of the studied probe 1 with an increase in hydrogen ions concentration is based on the hindering of enhanced photo-induced electron transfer (PET) process. Moreover, the pH sensor possesses a highly selective response to H(+) in the presence of metal ions, anions and other bioactive small molecules which would be interfere with its fluorescent pH response...
January 12, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28109808/selective-adsorption-of-pb-ii-ions-by-amylopectin-g-poly-acrylamide-co-acrylic-acid-a-bio-degradable-graft-copolymer
#6
Dinabandhu Sasmal, Jayanta Maity, Haradhan Kolya, Tridib Tripathy
Amylopectin-g-poly (acrylamide-co-acrylic acid) [AP-g-poly (AM-co-AA)] was synthesised in water medium by using potassium perdisulphate as an initiator. The graft copolymer was characterized by molecular weight determination by size exclusion chromatography (SEC), fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscope (SEM) studies, thermal analysis, measurement of neutralisation equivalent and biodegradation studies. The graft copolymer was used for Pb (II) ion removal from aqueous solution...
January 18, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28109327/effects-of-intrinsic-and-extrinsic-factors-on-aggregation-of-physiologically-important-intrinsically-disordered-proteins
#7
L Breydo, J M Redington, V N Uversky
Misfolding and aggregation of proteins and peptides play an important role in a number of diseases as well as in many physiological processes. Many of the proteins that misfold and aggregate in vivo are intrinsically disordered. Protein aggregation is a complex multistep process, and aggregates can significantly differ in morphology, structure, stability, cytotoxicity, and self-propagation ability. The aggregation process is influenced by both intrinsic (e.g., mutations and expression levels) and extrinsic (e...
2017: International Review of Cell and Molecular Biology
https://www.readbyqxmd.com/read/28109187/antimicrobial-and-antioxidant-activities-of-saccharomyces-cerevisiae-ifst062013-a-potential-probiotic
#8
Md Fakruddin, Md Nur Hossain, Monzur Morshed Ahmed
BACKGROUND: Probiotic yeast has become a field of interest to scientists in recent years. METHODS: Conventional cultural method was employed to isolate and identify yeast and standard methods were used to determine different probiotic attributes, antimicrobial and antioxidant properties. RESULTS: This study reports potential probiotic properties of a strain of S. cerevisiae IFST 062013 isolated from fruit. The isolate is tolerant to a wide range of temperature and pH, high concentration of bile salt and NaCl, gastric juice, intestinal environment, α-amylase, trypsin and lysozyme...
January 21, 2017: BMC Complementary and Alternative Medicine
https://www.readbyqxmd.com/read/28108957/effect-of-temperature-on-surface-characteristics-of-nitrogen-ion-implanted-biocompatible-titanium
#9
Hossein Aghajani, Mohsen Sadeghpour Motlagh
It has been established that nitrogen implantation can modify metals surface properties such as corrosion, wear, friction, etc. Recent studies have shown that nitrogen implantation into titanium and its alloys leads to the formation of titanium nitride, which has interesting biological, chemical, and mechanical properties. In the present investigation, commercially pure biocompatible titanium implanted by nitrogen. Implantation of ions performed at 80 keV and a dose of 2.1 × 10(18) ions/cm(2) at four different temperatures of 300, 473, 673 and 873 k...
February 2017: Journal of Materials Science. Materials in Medicine
https://www.readbyqxmd.com/read/28108654/revealing-the-role-of-the-product-metal-in-dna-polymerase-%C3%AE-catalysis
#10
Lalith Perera, Bret D Freudenthal, William A Beard, Lee G Pedersen, Samuel H Wilson
DNA polymerases catalyze a metal-dependent nucleotidyl transferase reaction during extension of a DNA strand using the complementary strand as a template. The reaction has long been considered to require two magnesium ions. Recently, a third active site magnesium ion was identified in some DNA polymerase product crystallographic structures, but its role is not known. Using quantum mechanical/ molecular mechanical calculations of polymerase β, we find that a third magnesium ion positioned near the newly identified product metal site does not alter the activation barrier for the chemical reaction indicating that it does not have a role in the forward reaction...
January 20, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28108412/deciphering-the-mechanistic-insight-into-the-stoichiometric-ratio-dependent-behavior-of-cu-ii-on-bsa-fibrillation
#11
Ajeet Singh, Poulami Datta, Lalit M Pandey
Various metal ions are recently implicated in protein aggregates and are associated with numerous neurodegenerative diseases. In the present work, we have scrutinized the effect of stoichiometric variation of Cu(II) on BSA fibrillation at physiological pH 7.4 through Thioflavin-T dye binding study, residual protein concentration, Fourier Transform Infrared spectroscopy (FTIR), Dynamic Light Scattering (DLS), Atomic Force Microscopy (AFM) and Isothermal Titration Calorimetry (ITC). Fibrillation kinetics was studied through ThT fluorescence, which illustrated dependency on stoichiometric ratio of Cu(II)...
January 17, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28108075/catalytic-potential-of-selected-metal-ions-for-bioleaching-and-potential-techno-economic-and-environmental-issues-a-critical-review
#12
REVIEW
Ashish Pathak, Liam Morrison, Mark Gerard Healy
Bioleaching is considered to be a low-cost, eco-friendly technique for leaching valuable metals from a variety of matrixes. However, the inherent slow dissolution kinetics and low metal leaching yields have restricted its wider commercial applicability. Recent advancements in bio-hydrometallurgy have suggested that these critical issues can be successfully alleviated through the addition of a catalyst. The catalyzing properties of a variety of metals ions (Ag(+), Hg(++), Bi(+++), Cu(++), Co(++) etc.) during bioleaching have been successfully demonstrated...
January 6, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28107961/new-approach-of-a-transient-icp-ms-measurement-method-for-samples-with-high-salinity
#13
Christina Hein, Jonas Michael Sander, Ralf Kautenburger
In the near future it is necessary to establish a disposal for high level nuclear waste (HLW) in deep and stable geological formations. In Germany typical host rocks are salt or claystone. Suitable clay formations exist in the south and in the north of Germany. The geochemical conditions of these clay formations show a strong difference. In the northern ionic strengths of the pore water up to 5M are observed. The determination of parameters like Kd values during sorption experiments of metal ions like uranium or europium as homologues for trivalent actinides onto clay stones are very important for long term safety analysis...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107955/matrix-isolation-with-an-ion-transfer-device-for-interference-free-simultaneous-spectrophotometric-determinations-of-hexavalent-and-trivalent-chromium-in-a-flow-based-system
#14
Shin-Ichi Ohira, Koretaka Nakamura, Mitsuki Chiba, Purnendu K Dasgupta, Kei Toda
Chromium speciation by spectrophotometric determination of hexavalent chromium (Cr(VI)) with diphenylcarbazide (DPC) has several problems. These include: (1) the inability to directly detect trivalent chromium (Cr(III)) with DPC, (2) positive interference in Cr(VI) determination by other metal cations and (3) negative interference by any reducing agent present in the sample. These are addressed with an ion transfer device (ITD) in a flow injection analysis system. We previously developed the ITD for electrodialytic separations...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107952/lanthanide-coordination-polymer-probe-for-time-gated-luminescence-sensing-of-ph-in-undiluted-human-serum
#15
Yankai Huang, Baoxia Liu, Qi Shen, Xu Zhu, Yuanqiang Hao, Zhu Chang, Fang Xu, Peng Qu, Maotian Xu
Lanthanide coordination polymers (LCPs) have emerged as fascinating materials because of their specific structure and properties. In this work, utilizing hydrosoluble biomolecule of guanosine-5'-monophosphate (GMP) as bridging linker, lanthanide terbium ions (Tb(3+)) as metal nodes, and silver ions (Ag(+)) as sensitizers, we synthesized a pH responsive luminescent lanthanide CP probe of Tb/GMP/Ag. The probe possesses high luminescence due to the sensitization of Ag(+); While in alkaline solutions, Ag(+) in Tb/GMP/Ag immediately binds to OH(-), forming Ag2O precipitation and resulting in a distinct fluorescence quenching of Tb/GMP/Ag...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107934/tuning-sensitivity-of-a-simple-hydrazone-for-selective-fluorescent-turn-on-chemo-sensing-of-al-3-and-its-application-in-living-cells-imaging
#16
Faiz-Ur Rahman, Amjad Ali, Saira Khan Khalil, Rong Guo, Peng Zhang, Hui Wang, Zhan-Ting Li, Dan-Wei Zhang
Salicylaldehyde based hydrazones 2-((2-methyl-2-(pyridin-2-yl)hydrazono)methyl)phenol (SMPH), 4-methyl-2-((2-methyl-2-(pyridin-2-yl)hydrazono)methyl)phenol (MSMPH) and 4-fluoro-2-((2-methyl-2-(pyridin-2-yl)hydrazono)methyl)phenol (FSMPH) were prepared and structurally characterized. These hydrazones exhibited fluorescence "turn on" response toward Al(3+) in dimethyl formamide/water (DMF/H2O) (1: 1) mixture. SMPH showed enhanced emission (70 folds) as compared to MSMPH (46 folds) and FSMPH (28 folds) upon the addition of 3 equivalents of Al(3+)...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107921/highly-selective-enrichment-of-phosphopeptides-using-zr-4-immobilized-titania-nanoparticles
#17
Junyong Dai, Miaode Wang, Hailong Liu
It is urgent to selectively enrich trace phosphorylated proteins or peptides from complex biological sample for mass spectrometry (MS)-based phosphoproteomics. In this study, a novel immobilized metal affinity chromatography (IMAC) material with DOTA(1,4,7,10-tetraazacyclododecane N, N', N'', N'''-tetra-acetic acid) coated on the surface of TiO2 nanomaterials and functionalized with the metal ion Zr(4+)(TiO2@DOTA-Zr) has been synthesized successfully to improve the enrichment specificity and sensitivity for phosphopeptides...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107902/electrolyzing-synthesis-of-boron-doped-graphene-quantum-dots-for-fluorescence-determination-of-fe-3-ions-in-water-samples
#18
Li Chen, Chuanli Wu, Pan Du, Xiaowei Feng, Ping Wu, Chenxin Cai
This work reports a facile electrolyzing method to synthesize boron-doped graphene quantum dots (BGQDs) and uses the BGQDs as a fluorescent probe to determine Fe(3+) ion levels in water samples. The BGQDs were produced by oxidizing graphite in an aqueous borax solution at pH 7; then, the borate solution was filtered with BGQDs, and the borate was dialyzed from the filtrate, leaving a solution of BGQDs in water. The amount of the B in the BGQDs can be adjusted by changing the concentration of borax used for the electrolyte...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107828/dissolvable-layered-double-hydroxide-as-an-efficient-nanosorbent-for-centrifugeless-air-agitated-dispersive-solid-phase-extraction-of-potentially-toxic-metal-ions-from-bio-fluid-samples
#19
Maryam Rajabi, Somayeh Arghavani-Beydokhti, Behruz Barfi, Alireza Asghari
In the present work, a novel nanosorbent namely layered double hydroxides with 4-amino-5-hydroxyl-2,7-naphthalendisulfonic acid monosodium salt interlayer anion (Mg-Al-AHNDA-LDH) was synthesized and applied as a dissolvable nanosorbent in a centrifugeless ultrasound-enhanced air-agitated dispersive solid-phase extraction (USE-AA-D-SPE) method. This method was used for the separation and preconcentration of some metal ions including Cd(2+), Cr(6+), Pb(2+), Co(2+), and Ni(2+) prior to their determination using the micro-sampling flame atomic absorption spectrometry (MS-FAAS) technique...
March 8, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28107756/photocatalytic-reduction-of-cs-i-ions-removed-by-combined-maghemite-titania-pva-alginate-beads-from-aqueous-solution
#20
Zohreh Majidnia, Mohamad Ali Fulazzaky
The presence of Cs(I) ions in nuclear wastewater becomes an important issue for the reason of its high toxicity. The development of adsorbent embedded metal-based catalysts that has sufficient adsorption capacity is expected for the removal of Cs(I) ions from contaminated water. This study tested the use of maghemite, titania and combined maghemite-titania polyvinyl alcohol (PVA)-alginate beads as an adsorbent to remove Cs(I) ions from aqueous solution with the variables of pH and initial concentration using batch experiments under sunlight...
January 17, 2017: Journal of Environmental Management
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