Novel treatment technologies for arsenic removal from water

University of Technology, Sydney. Faculty of Engineering.Arsenic is a toxic semi-metallic element that can be fatal to human health. It can have a significant adverse impact on the environment. Arsenic pollution in water has been found in many parts of the world, especially in developing countries such as Bangladesh, India, Nepal, and Vietnam. It is also detected in some areas of Australia. In rural area of Victoria, arsenic concentrations of up to 8 μg/L and 220 μg/L in groundwater and surface water have been reported. The arsenic contamination in water forced the water and health authorities to introduce stringent standards for arsenic levels in drinking water. World Health Organization (WHO) has recommended the arsenic level in drinking water to the stricter level to be 10 μg/L instead of 50 μg/L (since 1993). The U.S. Environmental Protection Agency (EPA) has lowered the maximum contaminant level (MCL) of arsenic from 50 μg/L to 10 μg/L. Rigorous criteria of arsenic level have been enforcing water authorities to identify and put into practice suitable and cost-effective arsenic removal technologies. The main objectives of the research described in this thesis were to develop and assess the potential and effectiveness of a new adsorbent medium namely iron oxide coated sponge (IOCSp) in removing arsenite [As(III)] and arsenate [As(V)J to an acceptable level in drinking water supplies. Arsenite [As(III)] and arsenate [As(V)] are the two predominant arsenic species found in groundwater. Regeneration of the exhausted IOCSp was also investigated. In addition, two other adsorbents: iron oxide coated sand 2 (IOCS-2), and surfactant modified zeolite - zero valent iron (SMZ/ZVI) were evaluated and their efficiency were compared with that of IOCSp. Effectiveness of membrane and photocatalysis hybrid systems in removing arsenic was studied. In this study, tap water (Sydney, Australia and Regina, Saskatchewan, Canada) spiked with predetermined amounts of As(III) and As(V) was used in the batch, tray and column studies. Raw water containing arsenic from Kelliher, Saskatchewan and Van Phuc Village, Hanoi, Vietnam were also investigated in the study. The research described below investigated optimised conditions for coating iron oxide on sponge by different coating conditions. Optimum conditions for coating the sponge with iron oxide were as follow: (i) pH value of coating condition of 4 (ii) time of contact between iron oxide and the sponge during coating of 10 hours; (iii) coating temperature of 110°C; and (iv) time of drying of sponge after the coating of 20 hours. The maximum adsorption capacities of IOCSp for As(III) and As(V) estimated by Langmuir, and Sips models were up to 4.18 and 4.6 mg/g of IOCSp, respectively. More than 92.4% of both As(III) and As(V) was removed after a contact period of 9 hours with the IOCSp (based on batch studies). The IOCSp adsorption equilibrium results with synthetic water fitted reasonably well with Freundlich, Langmuir, and Sips isotherms, indicating favourable adsorption. The performance of the IOCSp column was experimentally evaluated with synthetic water spiked with arsenic. The results showed that the IOCSp column could maintain high arsenic removal efficiency even after a long filtration time without any need for regeneration. For example, a filter packed even with very small amount of 25 g IOCSp maintained a consistent arsenic removal efficiency of 95% from synthetic water containing arsenic concentration of as high as 1,000 /μg/L. This produced a throughput volume of 153 and 178 L of water containing As(III) and As(V) respectively before any need for regeneration or disposal of IOCSp. A relatively small amount of IOCSp (8 g) could treat 42 - 63 L of arsenic contaminated groundwater (56 - 156 μg/L) in Kelliher (Canada) and in Hanoi (Vietnam) to a level of less than 20 μg/L. Studies showed that As(V) removal was better compared with As(III) removal. The results showed that the performance of IOCSp was superior to than that of iron oxide coated sand (IOCS-2) and surfactant modified zeolite - zero valent iron (SMZ/ZVI) in terms of weight of media. The IOCSp, once exhausted, can be regenerated with a small amount of sodium hydroxide 0.3M. The regenerated IOCSp did not have any significant decrease in removal effectiveness as compared to the fresh IOCSp. Photooxidation experimental results also showed that photooxidation of As(III) to As(V) with titanium dioxide (Ti0₂) as photocatalyst is possible within minutes. Further, Ti0₂ can also adsorb both As(III) and As(V) on its surface. Thus, the photocatalysis reaction with Ti0₂ can reduce about 98% of arsenite from water containing 500 μg/L of arsenite. By adding nanoscale zero valent iron (nZVI) of 0.05 g/L in the photo reactor, arsenic removal can be significantly enhanced to a value less than 10 μg/L. The amount of TiO2 used in this photocatalysis hybrid system was only 20% of normal photocatalysis operation. Removal of arsenic by a membrane is highly dependent on the species of arsenic and the properties of membranes. About 57% of As(III) and 81% of As(V) removal from 500 μg/L arsenic solution could be achieved by nanofiltration (NF) of 700 molecular weight cutoff. This removal efficiency could be increased to more than 95% by an inline addition of 0.2 g/L of nZVI. This method is suitable when high quality effluent is required. In summary, the study demonstrated conclusively that iron oxide coated sponge is an excellent media for reducing arsenic. IOCSp filter can be used as an effective and economical treatment system in removing arsenic from contaminated groundwater. The merits of the IOCSp filter process are the consistent removal efficiency, long life cycle, and simplicity in operation, regeneration and disposal

Common methodological issues and suggested solutions in bone research.

Bone research is a dynamic area of scientific investigation that usually encompasses multidisciplines. Virtually all basic cellular research, clinical research and epidemiologic research rely on statistical concepts and methodology for inference. This paper discusses common issues and suggested solutions concerning the application of statistical thinking in bone research, particularly in clinical and epidemiological investigations. The issues are sample size estimation, biases and confounders, analysis of longitudinal data, categorization of continuous data, selection of significant variables, over-fitting, P-values, false positive finding, confidence interval, and Bayesian inference. It is hoped that by adopting the suggested measures the scientific quality of bone research can improve

Performance Analysis of Protograph LDPC Codes over Large-Scale MIMO Channels with Low-Resolution ADCs

© 2013 IEEE. Protograph LDPC (P-LDPC) codes and large-scale multiple-input multiple-output (LS-MIMO) are cornerstones of 5G and future wireless systems, thanks to their powerful error-correcting capability and high spectral efficiency. To alleviate the high complexity in signal detection/decoding that dramatically grows with the number of antennas (in the order of tens or even hundreds), low-resolution analog-to-digital converters (ADCs) and joint detection and decoding using factor graph have recently attracted paramount interest. Unlike high-resolution ADCs, by using a small number of bits to quantize the received signal, low-resolution ADCs help reduce the hardware cost and power consumption of the RF circuit of practical LS-MIMO transceivers. Such a very much desirable reduction comes at the cost of additional quantization noise, introduced by low-resolution ADCs. This work aims to provide a unified framework to analyze the impact of the low-resolution ADCs on the performance of P-LDPC codes in practical LS-MIMO systems. It is worth noting that the previous analytical tools that have been used to evaluate the performance of P-LDPC codes do not account for the quantization noise effect of the low-resolution ADCs and the fact that the covariance of quantization noise depends on the fading channels. This article addresses this shortcoming by first leveraging the additive quantization noise model. We then derive the expression of extrinsic information for the belief-propagation LS-MIMO detector. The mutual information functions, which are the core elements of our proposed protograph extrinsic information transfer (PEXIT) algorithm, are analyzed for LS-MIMO communication systems. Our proposed PEXIT algorithm allows us to analyze and predict the impact of the low-resolution ADCs on the performance of P-LDPC codes, considering various input parameters, including the LS-MIMO configuration, the code rate, and the maximum number of decoding iterations, and the code structure. Based on our extensive analytical and simulation results, we found that the performance of 3-bit and 4-bit ADC systems only have a small gap to that of the unquantized systems. Especially when the 5-bit ADC scheme is applied, the performance loss is negligible. This finding sheds light on the practical design of LS-MIMO systems using P-LDPC codes

Post-GWAS Polygenic Risk Score: Utility and Challenges.

Over the past decade, through genome-wide association studies, more than 300 genetic variants have been identified to be associated with either BMD or fracture risk. These genetic variants are common in the general population, but they exert small to modest effects on BMD, suggesting that the utility of any single variant is limited. However, a combination of effect sizes from multiple variants in the form of the polygenic risk score (PRS) can provide a useful indicator of fracture risk beyond that obtained by conventional clinical risk factors. In this perspective, we review the progress of genetics of osteoporosis and approaches for creating PRSs, their uses, and caveats. Recent studies support the idea that the PRS, when integrated into existing fracture prediction models, can help clinicians and patients alike to better assess the fracture risk for an individual, and raise the possibility of precision risk assessment. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research

Quantification of the relative contribution of estrogen to bone mineral density in men and women

Background: The study quantified the relative contributions of estrogen (E2) and total testosterone (TT) to variation in bone mineral density in men and women. Methods. This was a cross-sectional study which involved 200 men and 415 women aged 18 to 89 years. BMD at the lumbar spine (LS) and femoral neck (FN) was measured by DXA. Serum levels of E2 and TT were measured by electrochemiluminescence immunoassays. The association between E2, TT, and BMD was analyzed by the multiple linear regression model, adjusting for age and BMI. The contribution of each hormone to the variation in BMD was quantified by the bootstrap method. Results: In women, higher serum levels of E2, but not TT, were significantly associated with greater BMD at the FN (P = 0.001) and LS (P < 0.0001). In men, higher serum levels of E2 were independently associated with greater FNBMD (P = 0.008) and LSBMD (P = 0.086). In the multiple linear regression model, age, body weight and E2 accounted for 50-55% variance in FNBMD, and 25% (in men) and 48% (in women) variance in LSBMD. Variation in E2 accounted for 2.5% (95% CI 0.4 - 7.8%) and 11.3% (95% CI 8.1 - 15.3%) variation in FNBMD in men and women, respectively. Moreover, E2 contributed 1.2% (95% CI 0.1 - 5.8%) and 11.7% (95% CI 8.5 - 15.9%) variation in LSBMD in men and women, respectively. Conclusions: Estrogen is more important than testosterone in the determination of age-related bone mineral density men and women of Vietnamese background. However, the relative contributions of estrogen to bone mineral density in men are likely modest. © 2013 Ho-Pham et al.; licensee BioMed Central Ltd

Combinative effects of Thanh Hao Miet Giap Thang (sweetwormwood and tortoise shell decoction) ingredients on antioxidative activity in vitro

Background: Traditional formulae usually exhibit therapeutic effects through the combinations of different ingredients. The purpose of this study was to investigate in vitro anti-oxidative activity of Thanh Hao Miet Giap Thang (THMGT) (Sweet Wormwood and Tortoise Shell Decoction) formula and the interactions of its ingredients leading to the overall anti-oxidative effect.Materials and Methods: We prepared 31 combinations containing two to four of the five ingredients including Herba Artemisia apiacea L (HbA),Carapax Trionycis (Tryonix sinensis) (CT), Rhizoma Anemarrhenae (Anemarrhena asphodeloides) (RzA), Radix Rehmanniae (Rehmannia glutinosaLibosch) (RdR), Moutan Cortex (Paeonia suffruticosa) (MC). These  combinations were tested for anti-oxidative activity using DCFH-DA and DPPH assays on Hep G2 cells. We also analyzed changes in expression of genes involved in antioxidant defense system including Nuclear Factor Erythroid-Derived 2-Like 2 (NFE2L2), catalase (CAT), heme oxygenase-1 (HO-1), glutathione peroxidase (GPx), cytoplasmic superoxide dismutase (SOD1), mitochondrial superoxide dismutase (SOD2).Results: The complete formula and all combinations containing Moutan Cortex showed high antioxidant activity in both radical solution-basedchemical assay and cellular-based assay. On the contrary, Carapax Trionycis displayed inhibitory effect on the overall antioxidant activity whenpresent in a combination, an effect clearly emphasized in cellular-based assay. Hep G2 cells treated with the formula showed increased geneexpression of HO-1 and SOD2 while expression of CAT, SOD1, GPx was unchanged.Conclusion: Our results suggested that THMGT had anti-oxidative activity essentially through intrinsic reducing capacities and the overall activity ofthe formula resulted from enhancing and inhibiting interactions of  ingredients.Key words: Thanh Hao Miet Giap Thang, Sweet Wormwood and Tortoise Shell Decoction, antioxidant, traditional formulaAbbreviations: THMGT, Thanh Hao Miet Giap Thang; HbA, Herba Artemisia apiacea; CT, Carapax Tryonicis; RzA, Rhizoma Anemarrhenae; MC,Moutan Cortex; RdR, Radix Rehmanniae; ROS, Reactive oxygen species; NFE2L2, Nuclear Factor Erythroid-Derived 2-Like 2; CAT, catalase; GPx,glutathione peroxidase; SOD1, cytoplasmic superoxide dismutase; SOD2, mitochondrial superoxide dismutase; HO-1, heme oxygenase-1

Removing arsenic from water with an original and modified natural manganese oxide ore: batch kinetic and equilibrium adsorption studies

© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. Arsenic contamination of drinking water is a serious water quality problem in many parts of the world. In this study, a low-cost manganese oxide ore from Vietnam (Vietnamese manganese oxide (VMO)) was firstly evaluated for its performance in arsenate (As(V)) removal from water. This material contains both Mn (25.6%) and Fe (16.1%) mainly in the form of cryptomelane and goethite minerals. At the initial As(V) concentration of 0.5 mg/L, the adsorption capacity of original VMO determined using the Langmuir model was 0.11 mg/g. The modified VMOs produced by coating VMO with iron oxide (Fea-VMO) and zirconium oxide (Zra-VMO) at 110 °C and 550 °C achieved the highest As(V) adsorption capacity when compared to three other methods of VMO modifications. Langmuir maximum adsorption capacities of Fea-VMO and Zra-VMO at pH 7.0 were 2.19 mg/g and 1.94 mg/g, respectively, nearly twenty times higher than that of the original VMO. Batch equilibrium adsorption data fitted well to the Langmuir, Freundlich, and Temkin models and batch kinetics adsorption data to pseudo-first order, pseudo-second order, and Elovich models. The increase of pH progressively from 3 to 10 reduced As(V) adsorption with a maximum reduction of 50–60% at pH 10 for both original and modified VMOs. The co-existing oxyanions considerably weakened the As(V) removal efficiency because they competed with As(V) anions. The competition order was PO43− > SiO32− > CO32− > SO42−. The characteristics of the original and modified VMOs evaluated using SEM, FTIR, XRD, XRF, surface area, and zeta potential explained the As(V) adsorption behaviour

The Vietnam Osteoporosis Study: Rationale and design.

ObjectivesOsteoporosis and fracture impose a significant health care burden on the contemporary populations in developing countries. The Vietnam Osteoporosis Study (VOS) sought to assess the burden of osteoporosis and its comorbidities in men and women.MethodsThe study was designed as a population-based family investigation in which families were randomly recruited from Ho Chi Minh City, Vietnam. Individuals were assessed for bone health, including bone mineral density (BMD) and body composition and trabecular and cortical bone properties by pQCT (peripheral quantitative computed tomography). Fasting blood samples were obtained for the analysis of plasma glucose, glycosylated hemoglobin, and bone turnover markers. Genomic DNA extraction from whole blood samples for further genetic and genomic analyses.ResultsWe have recruited more than 4157 individuals from 817 families. The average age of participants was 51, with approximately 45% of the individuals aged 50 years and older. Approximately 3% of participants were obese (body mass index ≥ 30 kg/m2), and 21% were overweight. Notably, 11% of participants aged 40 years and older were diabetic. Among those aged 50 years and older, approximately 14% of women and 5% of men had osteoporosis (i.e., femoral neck BMD T-scores ≤ -2.5). There were modest correlations between volumetric BMD and areal BMD.ConclusionsVOS is a major bone research project in Vietnam aimed at comprehensively documenting the burden osteoporosis, its co-occurrence of chronic diseases, and their underlying etiologies. The Study will make important contributions to the literature of bone health worldwide

Discordance in the diagnosis of diabetes: Comparison between HbA1c and fasting plasma glucose

© 2017 Ho-Pham et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Objective HbA1c has been introduced as a complementary diagnostic test for diabetes, but its impact on disease prevalence is unknown. This study evaluated the concordance between HbA1c and fasting plasma glucose (FPG) in the diagnosis of diabetes in the general population. Materials and methods The study was designed as a population based investigation, with participants being sampled from the Ho Chi Minh City, Vietnam. Blood samples were collected after overnight fasting and analyzed within 4 hours after collection. HbA1c was measured with high pressure liquid chromatography (Arkray Adams, Japan). FPG was measured by the hexokinase method (Advia Autoanalyzer; Bayer Diagnostics, Germany). Diabetes was defined as HbA1c 6.5% or FPG 7.0 mmol/L. Prediabetes was classified as HbA1c between 5.7% and 6.4%. Results The study included 3523 individuals (2356 women) aged 30 years and above. Based on the HbA1c test, the prevalence of diabetes and prediabetes was 9.7% (95%CI, 8.7–10.7%; n = 342) and 34.6% (33.0–36.2; n = 1219), respectively. Based on the FPG test, the prevalence of diabetes and prediabetes was 6.3% (95%CI, 5.5–7.2%; n = 223) and 12.1% (11.1–13.2; n = 427). Among the 427 individuals identified by FPG as "pre-diabetes", 28.6% were classified as diabetes by HbA1c test. The weighted kappa statistic of concordance between HbA1c and FPG was 0.55, with most of the discordance being in the prediabetes group. Conclusion These data indicate that there is a significant discordance in the diagnosis of diabetes between FPG and HbA1c measurements, and the discordance could have significant impact on clinical practice. FPG appears to underestimate the burden of undiagnosed diabetes