A water‐soluble amphoteric copolymer: Synthesis and its dispersion properties on cement particles

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We describe the case of a 12‐year‐old Hispanic male with a clinical and molecular diagnosis of Simpson–Golabi–Behmel Syndrome (SGBS) who subsequently developed metastatic medulloblastoma. While individuals with SGBS have been documented to have increased risk for intra‐abdominal tumors such as Wilms tumor and neuroblastoma, medulloblastomas, or CNS tumors in general, have not been reported in patients with this syndrome. Our patient was clinically diagnosed with SGBS as an infant. He presented with many of the common features of the syndrome, such as cleft palate, macroglossia, post‐axial polydactyly, “coarse” facial features, and ventricular septal defects (VSDs). Molecular testing performed in April 2009 confirmed the SGBS diagnosis. This testing detected a large intragenic deletion in the GPC3 gene (more than 500 kb, 8 exons) extending from intron 2, 37 kb downstream of exon 2, to the 5′ end of the gene, deleting exons 1 and 2. However, subsequent testing by gene‐centric high‐density array comparative genomic hybridization (aCGH) detected a deletion encompassing only exon 2. Therefore, the exact 5′ boundary of the deletion cannot currently be determined, due to an apparent complex rearrangement upstream of exon 1. We present this case of metastatic medulloblastoma as a unique malignancy in a patient with SGBS. © 2012 Wiley Periodicals, Inc.

Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 90%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effects of an amphoteric copolymer on the properties of cementitious materials

Sheen

Weng

et al. 2011

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Preparation of amphoteric polycarboxylate superplasticizers and their performances in cementitious system

Jiang

Kong

et al. 2014

A series of amphoteric polycarboxylate (PC) polymers were synthesized by radical copolymerization of acrylic acid (AA), [3-(methacryloylamino) propyl] trimethylammonium chloride (MAPTAC) and x-methoxypolyoxyethylene methacrylate ester (MPEGMA). Cationic groups were introduced in to PC molecules with expectation of less retardation effect on cement hydration compared to the traditional anionic PC superplasticizers. The content of cationic groups in polymer was varied by changing the monomer ratio of MAPTAC to AA in the synthesis recipes. The structure of the synthesized amphoteric PCs was verified by gel permeation chromatography (GPC) and Fourier transform infrared spectroscopy (FTIR). The performances of the amphoteric PCs were evaluated by measurement of flowability and zeta-potential of cement pastes and adsorption amount of PC in cement pastes. Impacts of the PCs on cement hydration were studied by isothermal calorimetry. It is concluded that both anionic and cationic PC polymers can be effectively adsorbed onto the surface of cement particles and thus change the zeta potential of cement pastes. The adsorption amounts of the amphoteric PCs decrease with increasing content of cationic units. A proper incorporation of cationic units into PC polymers may lead to a higher fluidizing performance in fresh cement pastes. The amphoteric PC polymers with higher content of cationic units show less retardation effect on cement hydration and hence higher early strength of cementitious materials may be achieved by using amphoteric PCs with appropriated content of cationic units without losing their plasticizing efficiency.

An amphoteric hydrogel: Synthesis and application as an internal curing agent of concrete

Liu

Huang

Zhuang

et al. 2015

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A new crosslinked amphoteric hydrogel (PAC) was synthesized and evaluated as an internal curing agent of concrete. PAC was prepared from acrylamide (AM) and 4-(2-((carboxylatomethyl)dimethylammonio)ethoxy)24-oxobut-2-enoate (CMD) through free-radical polymerization by using ammonium persulfate (APS) as an initiator and methylene-bisacrylamide (MBA) as a crosslinker. The structure of the prepared polymer was verified by the IR spectra. The effects of the polymerization variables on the swelling capacity of PAC were investigated. The water absorbency of PAC was found to increase with increasing CMD/AM ratio, reach a maximum value, and decrease afterword. Increase of either APS or MBA content decreased the water absorbency. The highest water absorbency of PAC hydrogel (P7) achieved in deionized water, 0.1M NaCl solutions and 0.1M CaCl 2 solutions, was 306 g/g, 32 g/g, and 22 g/g, respectively. Compared with a commercial acrylate-based hydrogel 283HA, P7 was less sensitive to the existence of Ca 21 ions in cement pore solutions, and more effective in reducing the cracking tendency of cement pastes. Finally, mortars incorporated with proper amounts of P7 showed smaller drying shrinkage and higher compressive strength than that without hydrogel present. V C 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42175.