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Chemical binding

About: Chemical binding is a research topic. Over the lifetime, 1822 publications have been published within this topic receiving 52516 citations.


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Journal ArticleDOI
TL;DR: Results suggest that selective TU incorporation in pigmented melanomas and other melanin-producing systems is due to the covalent binding to dopaquinone, produced by tyrosinase catalyzed oxidation of tyrosine.

19 citations

Journal ArticleDOI
TL;DR: In this article, the equilibrium and kinetic adsorption of arsenic on six different adsorbents were investigated with one synthetic and four natural types (two surface and two ground) of water.
Abstract: The equilibrium and kinetic adsorption of arsenic on six different adsorbents were investigated with one synthetic and four natural types (two surface and two ground) of water. The adsorbents tested included magnetic ion exchange resins (MIEX), hydrous ion oxide particles (HIOPs), granular ferric hydroxide (GFH), activated alumina (AA), sulfur modified iron (SMI), and iron oxide-coated mic rosand (IOC-M), which have different physicochemical properties (shape, charge, surface area, size, and metal content). The results showed that adsorption equilibriums were achieved within a contact period of 20 min. The optimal doses of adsorbents determined for a given equilibrium concentration of Ceq = 10 µg/L were 500 mg/L for AA and GFH, 520–1,300 mg/L for MIEX, 1,200 mg/L for HIOPs, 2,500 mg/L for SMI, and 7,500 mg/L for IOC-M at a contact time of 60 min. At these optimal doses, the rate constants of the adsorbents were 3.9, 2.6, 2.5, 1.9, 1.8, and 1.6 1/hr for HIOPs, AA, GFH, MIEX, SMI, and IOC-M, respectively. The presence of silicate significantly reduced the arsenic removal efficiency of HIOPs, AA, and GFH, presumably due to the decrease in chemical binding affinity of arsenic in the presence of silicate. Additional experiments with natural types of water showed that, with the exception of IOC-M, the adsorbents had lower adsorption capacities in ground water than with surface and deionized water, in which the adsorption capacities decreased by approximately 60–95%.

19 citations

Journal ArticleDOI
TL;DR: Minimally toxic 9–13 nm diameter porous carbon nanospheres (PNs) were synthesized by oxidative cutting of porous carbon matrices obtained by carbonization of pasture grass, human hair and sucrose, and grass-derived PNs with superior surface area, porosity and graphitic content demonstrate a significant loading of the drug both by chemical binding and physisorption.
Abstract: Cost-effective anti-cancer drug delivery vehicles that can ensure controlled and targeted transportation of drug molecules are pertinent to modern day biomedical applications. Minimally toxic 9–13 nm diameter porous carbon nanospheres (PNs) were synthesized by oxidative cutting of porous carbon matrices (PCs) obtained by carbonization of pasture grass, human hair and sucrose. Among them, the grass-derived PNs (PN-G) with superior surface area, porosity and graphitic content demonstrate a significant loading of the drug both by chemical binding and physisorption. Polyethylenimine (PEI) and folic acid (FA) functionalization maintain therapeutic efficacy of the drug doxorubicin (DOX) to the targeted folate receptor (FR) overexpressed human cervical cancer cells (HeLa) and human breast cancer cells (MDA-MB-231) through receptor mediated endocytosis whereas FR deficient normal cells (human embryonic kidney 293) exhibit substantially lower endocytosis under identical conditions. Moreover, upon loading cell-impe...

19 citations

Journal ArticleDOI
TL;DR: In this article, the effect of sputtering power on the core level binding energies, chemical binding configurations, crystallographic structure, surface morphology and electrical and optical properties of molybdenum oxide was systematically studied.
Abstract: Thin films of molybdenum oxide were formed on glass and silicon substrates by sputtering of molybdenum target under various sputtering powers in the range 2.3–6.8 W/cm2, at a constant oxygen partial pressure of 2 × 10−4 mbar and substrate temperature 523 K employing DC magnetron sputtering technique. The effect of sputtering power on the core level binding energies, chemical binding configurations, crystallographic structure, surface morphology and electrical and optical properties was systematically studied. X-ray photoelectron spectroscopic studies revealed that the films formed at sputtering powers less than 5.7 W/cm2 were mixed oxidation states of Mo5+ and Mo6+. The films formed at 5.7 W/cm2 contained the oxidation state Mo6+ of MoO3. Fourier transform infrared spectra contained the characteristic optical vibrations. The presence of a sharp absorption band at 1,000 cm−1 in the case of the films formed at 5.7 W/cm2 was also conformed the existence of α-phase MoO3. X-ray diffraction studies also confirmed that the films formed at sputtering powers less than 5.7 W/cm2 showed the mixed phase of α-and β-phase of MoO3 where as at sputtering power of 5.7 W/cm2 showed single phase α-MoO3. The electrical conductivity of the films increased from 8 × 10−6 to 1.2 × 10−4 Ω−1 cm−1, the optical band gap decreased from 3.28 to 3.12 eV and the refractive index decreased from 2.12 to 1.94 with the increase of sputtering power from 2.3 to 6.8 W/cm2, respectively.

19 citations

Journal ArticleDOI
TL;DR: In this paper, the authors combined surface oxidation by plasma and chemical binding of polyvinyl alcohol (PVA) to obtain long-term stability of hydrophilic PDMS surfaces.

18 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20223
202178
202076
201989
201866
201769