Performance of industrial by-products in controlled low-strength materials (CLSM)

As the construction industry continues to recognise the importance of sustainable development, technologies such as controlled low-strength material (CLSM) have come to the forefront as viable means of safely and efficiently using by-product and waste materials in infrastructure applications. CLSM, also known as flowable fill, can be defined as an engineered backfill material containing fine aggregates, Portland cement, water and a by-product material. CLSM can provide an economically and technically feasible alternative to conventional fill materials because of potential cost savings related to its unique and often superior technical properties. In this present experimental study, three industrial by-products, namely fly ash (FA), rice husk ash (RHA) and quarry dust (QD), were used as constituent materials in CLSM. Mixture proportions were developed for CLSM containing these industrial by-products and were tested in the laboratory for various properties, such as flowability, unconfined compressive strength (UCS), stress-strain behaviour, density, water absorption and volume changes. Comparison between the two pozzolanic materials, namely FA and RHA, for their potential to produce an effective CLSM has been made. It can be observed from the results that by-product materials such as FA, RHA and QD can be successfully used in CLSM. This successful utilization of by-product materials is important to sustainable development and is the focus of this research.     

An inexact multi-objective dynamic model and its application in China for the management of municipal solid waste

With the development of science and technology, solid waste management has become a serious environmental problem for most communities all over the world. This paper presents a multi-objective optimization model for the management of municipal solid waste (MSW) via an uncertainty approach. In this model, the system cost of solid waste management and the environmental impact are considered as the main objectives, and some necessary constraints based on the characteristics of China are included; additionally, Pollution loss theory is applied to evaluate the environmental impact.This model is applied to the City of Fo Shan, China. Compared with the primary project of Fo Shan, which is provided by the government, the results of the optimization procedure show that the overall system cost could be reduced by $1–2.4/ton, i.e., $3.7 million/yr. The model presented in this paper was proven to be an effective response to the multi-objective solid waste management problem, and provides a new technique to optimize MSW management and operation. Why is the optimization result better? By analyzing the modelling with respect to function, constraints, and results, we conclude that the profit would be augmented due to the amount of the waste that would be treated by recycling technology, which would increase rapidly during the planning time; thus, the total system cost could be reduced accordingly.     

Zinc and cobalt phytoextraction by different plant species

Plant species sorghum (Sorghum vulgar L.), clover (Trifolium pratense L.), panikum (Panicum antidotal), and canola (Brassica napus) were tested to determine their phytoremediation potential. After a period of about 90 days, plant samples (shoots and roots) and soil samples (before and after cultivation) were collected for zinc and cobalt analyses using atomic absorption spectrometry. The highest zinc uptake was observed in canola, while panikum grass showed a high zinc accumulation affinity compared to sorghum and clover. Calculation of the recovery percentage, based on the amount of zinc removed from the soil after cultivation, ranged between 12.8 and 36.3 percent of the total initial zinc. Canola shoots exhibited the highest cobalt uptake compared to the other plant species. Calculation of the recovery percentage based on cobalt removed from the soil after cultivation ranged between 10.1 and 40.7 percent of the total initial cobalt concentration. © 2007 Wiley Periodicals, Inc. *

1 This article is a U.S. Government work and, as such, is in the public domain of the United States of America.

     

Assessment of airborne environmental bacteria and related factors in 25 underground railway stations in Seoul,Korea

This study assessed bacterial concentrations in indoor air at 25 underground railway stations in Seoul, Korea, and investigated various related factors including the presence of platform screen doors (PSD), depth of the station, year of construction, temperature, relative humidity, and number of passengers. A total of 72 aerosol samples were collected from all the stations. Concentrations of total airborne bacteria (TAB) ranged from not detected (ND) to 4997 CFU m^?3, with an overall geometric mean (GM) of 191 CFU m^?3. Airborne bacteria were detected at 23 stations (92%) and Gram-negative bacteria (GNB) were detected at two stations (8%). TAB concentrations of four stations (16%) exceeded 800 CFU m^?3, the Korea indoor bio-aerosol guideline. The results of the study showed that TAB concentrations at the stations without PSD showed higher TAB concentrations than those with PSD, though not at statistically significant levels. TAB concentrations of deeper stations revealed significantly higher levels than those of shallower stations. Based on this study, it is recommended that mitigation measures be applied to improve the indoor air quality (IAQ) of underground railway stations in Seoul, with focused attention on deeper stations.     

Increased acidification in the rhizosphere of cactus seedlings induced by Azospirillum brasilense

Acidification of the rhizosphere of cactus seedlings (giant cardon, Pachycereus pringlei) after inoculation with the plant growth-promoting bacterium Azospirillum brasilense Cd, in the presence or absence of ammonium and nitrate, was studied to understand how to increase growth of cardon seedlings in poor desert soils. While ammonium enhanced rhizosphere and liquid culture acidification, inoculation with the bacteria enhanced it further. On the other hand, nitrate increased pH of the rhizosphere, but combined with the bacterial inoculation, increase in pH was significantly smaller. Bacterial inoculation with ammonium enhanced plant growth.     

High levels of maternal serum alpha-fetoprotein and human chorionic gonadotrophins leading to the diagnosis of combined neural tube defect and partial mole

A case of combined partial mole and neural tube defect is presented. The detection of high levels of both maternal serum (MS) alpha-fetoprotein (AFP) and human chorionic gonadotrophin (hCG) during the second trimester led to the ultrasonic demonstration of anencephaly, omphalocele, and partial mole. This is the first report of combined elevation of MSAFP and MShCG.     

Proposed guidelines for diagnosis of chromosome mosaicism in amniocytes based on data derived from chromosome mosaicism and pseudomosaicism studies

Currently, accepted protocol which has been developed at the Prenatal Diagnosis Laboratory of New York City (PDL) requires that when a chromosome abnormality is found in one or more cells in one flask, another 20–40 cells must be examined from one or two additional flasks. Chromosome mosaicism is diagnosed only when an identical abnormality is detected in cells from two or more flasks. In a recent PDL series of 12 000 cases studied according to this protocol, we diagnosed 801 cases (6.68 per cent) of single-cell pseudomosaicism (SCPM), 126 cases (1.05 per cent) of multiple-cell pseudomosaicism (MCPM), and 24 cases (0.2 per cent) of true mosaicism. Pseudomosaicism (PM) involving a structural abnormality was a frequent finding (2/3 of SCPM and 3/5 of MCPM), with an unbalanced structural abnormality in 55 per cent of SCPM and 24 per cent of MCPM. We also reviewed all true mosaic cases (a total of 50) diagnosed in the first 22000 PDL cases. Of these 50 cases, 23 were sex chromosome mosaics and 27 had autosomal mosaicism; 48 cases had numerical abnormalities and two had structural abnormalities. Twenty-five cases of mosaicism were diagnosed in the first 20 cells from two flasks, i.e., without additional work-up, whereas the other 25 cases required extensive work-up to establish a diagnosis (12 needed additional cell counts from the initial two culture flasks; 13 required harvesting a third flask for cell analysis). Our data plus review of other available data led us to conclude that rigorous efforts to diagnose true mosaicism have little impact in many instances, and therefore are not cost-effective. On the basis of all available data, a work-up for potential mosaicism involving a sex chromosome aneuploidy or structural abnormality should have less priority than a work-up for a common viable autosomal trisomy. We recommend revised guidelines for dealing with (1) a numerical versus a structural abnormality and (2) an autosomal versus a sex chromosome numerical aneuploidy. Emphasis should be placed on autosomes known to be associated with phenotypic abnormalities. These new guidelines, which cover both flask and in situ methods, should result in more effective prenatal cytogenetic diagnosis and reduced patient anxiety.     

Chromosomal abnormalities associated with a single umbilical artery

A single umbilical artery was seen in 10 out of 117 cytogenetically abnormal pregnancies. The abnormal karyotypes found to be associated with a single umbilical artery were trisomy 18 (n = 5), monosomy X (n = 2), triploidy (n = 1), sex chromosome (47,XYY; n = 1) and translocation (46t(X,5)(q13p15); n = 1). With the exception of the translocation case, all cases with a single umbilical artery had anatomical defects which were detectable ultrasonographically. This suggests that a single umbilical artery alone is not an indication for prenatal fetal karyotyping.     

Prenatal diagnosis of hydrocephalus-stenosis of the aqueduct of Sylvius by ultrasound in the first trimester of pregnancy. Report of two cases

Hydrocephalus-stenosis of the acqueduct of Sylvius sequence (HSAS) is characterized by hydrocephalus, macrocephaly, adducted thumbs, spasticity, agenesis of the corpus callosum and mental retardation. X-linked hydrocephalus is known to be due to mutations in the gene coding for the neural cell adhesion molecule L1 (L1-CAM) and diagnosis is made by identification of a mutation in the L1-CAM gene. Prenatal diagnosis of HSAS is usually suggested on ultrasound examination showing hydrocephalus in a male fetus associated with bilateral adducted thumbs. Mutation screening of the L1-CAM gene is indicated when neuropathological examination shows hypoplasia of the corticospinal tract associated with aqueductal stenosis. We report here two cases of HSAS diagnosed within the same family by ultrasound examination in the first trimester of pregnancy when bilateral adducted thumbs were the only early ultrasound marker. Copyright © 2001 John Wiley & Sons, Ltd.     

Maternal serum levels of dimeric inhibin A in pregnancies affected by trisomy 21 in the first trimester

Dimeric inhibin A was measured in maternal serum samples from 45 pregnancies affected by trisomy 21 and 493 samples from unaffected pregnancies at 10–14 weeks of gestation. Inhibin A levels in affected pregnancies were compared with levels of free β-hCG and PAPP-A in the same series. In the trisomy 21 group, the median multiple of the median (MoM) inhibin A was not significantly elevated (1.28 vs 1.00) with only 15.5% being above the 95th centile. In contrast, the median MoM free β-hCG was significantly increased (2.05 vs 1.00) with 36% above the 95th centile and PAPP-A was significantly reduced (0.49 vs 1.00) with 42% below the 5th centile. Inhibin A levels in the trisomy 21 group were significantly correlated with gestational age such that median levels rose from 1.04 at 11 weeks to 1.30 at 12 weeks and 1.67 at 13 weeks. These findings suggest that first trimester biochemical screening for trisomy 21, which is currently optimised using maternal serum free β-hCG and PAPP-A and fetal nuchal translucency, will not benefit from the inclusion of inhibin A. Copyright © 2001 John Wiley & Sons, Ltd.