A new water-soluble amphoteric copolymer (PAC) was synthesized and evaluated as a dispersion agent for cement particles. PAC was prepared from acrylamide and 2-(3-carboxyacryloyloxy)-N-(carboxymethyl)-N,N-dimethyl ethanaminium (CAC) through free-radical polymerization. The structure of the prepared polymer was verified by the IR spectra. The dispersion properties of PAC were evaluated by the minislump test on cement pastes. The test results indicate that this copolymer could disperse the cement particles and improve the fluidity of the cement pastes. Compared with a commercial superplasticizer, sulfonated naphthalene formaldehyde condensate, PAC showed better dispersion properties. This polymer, with about 16.7% CAC and a weight-average molecular weight of about 1 Â 10 5 , was most effective in dispersing cement particles and enhancing the fluidity of the cement pastes. This was attributed to the interaction and adsorption behavior of this admixture with cement particles.

This paper aims to employ combination of residual soil and Class F fly ash in developing a controlled low-strength material (CLSM), primarily used as backfilling material. In the mixture, surplus soil and concrete sand was blended well together with a given proportion of 6:4 by volume. Three levels of binder content (i.e. 80-, 100-and 130 kg/m3) and different percentages fly ash (i.e., 0%, 15%, 30%, and 45%) substituting to Portland cement were previously chosen for mix design. Several major engineering properties of the CLSM such as fresh density, flowability, setting time, water bleeding, unconfined compressive strength, and elastic modulus were investigated via a laboratory study. Testing results indicate that most of the proposed CLSM mixtures satisfy the requirements of excavatability as the 28-days compressive strength ranges from 0.3 to 1.4 MPa. In addition, increase in FA substituting to OPC resulted in workability improvement, setting time extension as well as compressive strength and elastic modulus reduction.

This paper presents two approaches, multiple linear regression (MLR) and artificial neural network (ANN), to develop predictive models for unconfined compressive strength of soil-based controlled low-strength material (CLSM). Our obtained laboratory data conducting on the soil-based CLSM were employed for analysis. Two strength prediction models were proposed: (1) strength is assumed to be a function of mix proportion and curing period; and (2) it is estimated from measured ultrasonic pulse velocity combined with effect of mixture parameters and curing ages. In each model, three predicted formulas were developed; one from MLR and two from ANN. It was showed that all the proposed equations have a well-predicted capacity.

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.