Input Concentration Research Articles

Double-Stranded DNA Virus Assemblages in Groundwater in Three Informal Urban Settlements in Sub-Saharan Africa Differ from Each Other

We mapped the double-stranded DNA (dsDNA) virus assemblage in groundwater below sub-Saharan urban poor settlements in Arusha (Tanzania), Dodowa (Ghana), and Kampala (Uganda). Our results indicated that ∼80% of dsDNA virus sequences matched the order of Caudovirales, i.e., indigenous bacteriophages; 1.8% of the dsDNA virus sequences matched those of viral pathogens that infect humans and larger animals, which we defined as so-called above-ground hosts. Within this group, the relative abundances of the genera Chordopoxvirinae, Alphaherpesvirinae, and Betairidovirinae were the highest. Culturable Escherichia coli bacteria were found even in deeper wells, indicating that all water was fecally contaminated. The community assemblages sampled in the cities were statistically significantly different from each other. Dissolved ions, population density, and sanitary status had no significant influence, but pH and latitude did. We concluded that the transport of dsDNA virus in groundwater was location specific but was not determined by input concentrations (i.e., related to population density) or related to groundwater chemistry. We hypothesize that other parameters, like the presence of macropores, cause these variations in these shallow, highly populated, heavily polluted terrestrial groundwater systems. Approximately 34% of Africa has similar hydrogeology, so this may affect many urban areas across the continent.

Greenhouse gas emissions in sludge ultrasonication followed by anaerobic digestion processes

This paper presents the greenhouse gas (GHG) emissions during ultrasonication of sludge and anaerobic digestion (AD) of the ultrasonicated sludge using mass-energy balance. Computation of the net energy (energy recovered - energy input) revealed that high solids concentration with low sonication specific energy provides positive net energy. Moreover, the GHG emissions can be minimised at low sonication specific energy input and high solids concentration compared to that of the control without sonication. Increase in temperature of sludge during sonication will reduce the energy input required for raising the sludge temperature to AD temperature and thus decreases the GHG emissions. With energy recovery from the methane produced in AD, the total GHG emissions can further be reduced, lower than that without energy recovery from methane.

Analysis of the Landfill Leachate Treatment System Using Arima Models: A Case Study in a Megacity

Leachate has been reported as the most significant source of landfill pollution. Predicting the characteristics of untreated and treated leachate may be useful during optimal scheduling of leachate treatment systems. The objective of this paper is to show an analysis of the operation of a landfill leachate treatment system in a Latin American megacity (Bogota, Colombia) by means of auto-regressive integrated moving average (ARIMA) models. A comparative analysis of the leachate treated with respect to reference legislation is carried out. The influence of climate variables during the operation of the treatment system is also considered. The results suggest that the concentrations of heavy metals (HMs), BOD5, and COD in untreated leachate do not follow the same annual cycles observed for the quantity of solid waste disposed within the landfill. This difference is possibly associated with the hydraulic retention time (HRT) of the leachate inside the conduction and pre-treatment system (storage/homogenization ponds). The ARIMA analysis suggests an HRT of up to one month (AR = 1) for the HMs identified as indicators of untreated leachate (Cu, Pb, and Zn). It is noted that the removal efficiency of HM indicators of the operation of the leachate treatment plant (Fe and Ni) is probably conditioned by operations carried out over a period of one month (AR = 1). The high input concentration of these HM indicators may prevent changing their ARIMA temporal structure during leachate treatment. This is reflected in the low removal efficiencies for all HMs under study (average = 26.1%).

Effective recovery of ytterbium through biosorption using crosslinked sericin-alginate beads: A complete continuous packed-bed column study

The recovery of rare-earth from secondary sources is essential for cleaner production. The development of natural biocomposites is promising for this purpose. Sericin is a waste protein from silk manufacturing. The highly polar groups on the surface of sericin facilitate blending and crosslinking with other polymers to produce biocomposites with improved properties. In this work, we investigate ytterbium recovery onto a natural biocomposite based on sericin/alginate/poly(vinyl alcohol) (SAPVA) in packed-bed column, aiming to establish a profitable application for sericin. Effects of flow rate and ytterbium inlet concentration showed that the highest exhaustion biosorption capacity (128.39 mg/g) and lowest mass transfer zone (4.13 cm) were reached under the operating conditions of 0.03 L/h and 87.95 mg/L. Four reusability cycles were performed under the optimum operating conditions using 0.3 mol/L HNO3. Ytterbium recovery was highly successful; desorption efficiency was higher than 97% and a final ytterbium-rich concentrate (3870 mg/L) was 44 times higher than input concentration. Regenerated beads characterization showed that the cation exchange mechanism plays a major function in continuous biosorption of ytterbium. SAPVA beads also showed higher biosorption/desorption performance for ytterbium than other competing ions. These results suggest the application of SAPVA may be an alternative for large-scale ytterbium recovery.

The operating diagram for a two-step anaerobic digestion model

The anaerobic digestion model ADM1 is a complex model which is widely accepted as a common platform for anaerobic process modeling and simulation. However, it has a large number of parameters and states that hinder its analytic study. Here, we consider the two-step simple model of anaerobic digestion named AM2, which is a four-dimensional system of ordinary differential equations. The AM2 model is able to adequately capture the main dynamical behavior of the full anaerobic digestion model ADM1 and has the advantage that a complete analysis for the existence and local stability of its steady states is available. We describe its operating diagram, which is the bifurcation diagram giving the behavior of the system with respect to the operating parameters, represented by the dilution rate and the input concentrations of the substrates. This diagram is very useful to understand the model from both the mathematical and biological points of view. It is shown that six types of behavior can be obtained for the long-term dynamics of the AM2 model, concerning the coexistence or extinction of one or both bacterial populations.

Quantifying the effectiveness of a saturated buffer to reduce tile NO3-N concentrations in eastern Iowa.

Agricultural drainage tiles are primary contributors to NO3-N export from Iowa croplands. Saturated buffers are a relatively new conservation practice that diverts tile water into a distribution tile installed in a riparian buffer parallel to a stream with the intent of enhancing NO3-N processing within the buffer. In this study, tile NO3-N concentration reductions were characterized through two different saturated buffers at a working farm site in eastern Iowa. Study objectives were to (1) evaluate the hydrogeology and water quality patterns in the saturated buffer and (2) quantify the reduction in tile NO3-N concentration from the saturated buffer installation. Results showed that the two saturated buffers are reducing NO3-N concentrations in tile drainage water from input concentrations of approximately 15 mg/l to levels < 1.5 mg/l at the streamside well locations. The reduction occurs rapidly in the fine-textured and organic-rich alluvial soils with most of the reduction occurring within 1.5 m of the distribution line. Denitrification is hypothesized as being primarily responsible for the concentration reductions based on soil and water chemistry conditions, completion of a geophysical survey (quantifying low potential for N loss to deeper aquifers), and comparisons to other similar Iowa sites. The study provides more assurance to new adopters that this practice can be installed in many areas throughout the Midwestern Cornbelt region.Supplementary informationThe online version contains supplementary material available at 10.1007/s10661-021-09297-3.

Ideal versus Nonideal Transport of PFAS in Unsaturated Porous Media

Per- and poly-fluoroalkyl substances (PFAS) adsorb at air-water interfaces during transport in unsaturated porous media. This can cause surfactant-induced flow and enhanced retention that is a function of concentration, which complicates characterization and modeling of PFAS transport under unsaturated conditions. The influence of surfactant-induced flow and nonlinear air-water interfacial adsorption (AWIA) on PFAS transport was investigated with a series of miscible-displacement transport experiments conducted with a several-log range in input concentrations. Perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and ammonium perfluoro 2-methyl-3-oxahexanoate (GenX) were used as model PFAS. The results were interpreted in terms of critical reference concentrations associated with PFAS surface activities and their relationship to the relevancy of transport processes such as surfactant-induced flow and nonlinear AWIA for concentration ranges of interest. Analysis of the measured transport behavior of PFAS under unsaturated-flow conditions demonstrated that AWIA was linear when the input concentration was sufficiently below the critical reference concentration. This includes the absence of significant arrival-front self-sharpening and extended elution tailing of the breakthrough curves, as well as the similarity of retardation factors measured for a wide range of input concentrations. Independently-predicted simulations produced with a comprehensive flow and transport model that accounts for transient variably-saturated flow, surfactant-induced flow, nonlinear rate-limited solid-phase sorption, and nonlinear rate-limited AWIA provided excellent predictions of the measured transport. A series of simulations was conducted with the model to test the specific impact of various processes potentially influencing PFOS transport. The simulation results showed that surfactant-induced flow was negligible and that AWIA was effectively linear when the input concentration was sufficiently below the critical reference concentration. PFAS retention associated with AWIA can be considered to be ideal in such cases, thereby supporting the use of simplified mathematical models. Conversely, apparent nonideal transport behavior was observed for experiments conducted with input concentrations similar to or greater than the critical reference concentration.

The evolution of stable silicon isotopes in a coastal carbonate aquifer on Rottnest Island, Western Australia

Abstract. Dissolved silicon (dSi) is a key nutrient in the oceans, but data regarding Si isotopes in coastal aquifers are not widely available. Here we investigate the Si isotopic composition of 12 fresh and 16 saline groundwater samples from Rottnest Island, Western Australia, which forms part of the world's most extensive aeolianite deposit (the Tamala Limestone formation). In total, two bedrock samples were also collected from Rottnest Island for Si isotope analysis. The δ30Si values of groundwater samples ranged from −0.4 ‰ to +3.6 ‰ with an average +1.6 ‰, and the rock samples were −0.8 ‰ and −0.1 ‰. The increase in δ30Si values in fresh groundwater is attributed to the removal of the lighter Si isotopes into secondary minerals and potentially also adsorption onto Fe (oxy)hydroxides. The positive correlations between δ30Si values and dSi concentrations (ρ = 0.59; p = 0.02) and δ30Si values and Cl, but not dSi and Cl concentrations, are consistent with vertical mixing between the younger fresh groundwater and the deeper groundwater, which have undergone a greater degree of water–rock interactions. This has produced a spatial pattern in δ30Si across the aquifer due to the local hydrogeology, resulting in a correlation between δ30Si and tritium activities when considering all groundwater types (ρ = −0.68; p = 0.0002). In the deeper aquifer, the inverse correlation between dSi and Cl concentrations (ρ = −0.79; p = 0.04) for the more saline groundwater is attributed to groundwater mixing with local seawater that is depleted in dSi (&lt; 3.6 µM). Our results from this well-constrained island aquifer system demonstrate that stable Si isotopes usefully reflect the degree of water–aquifer interactions, which is related to groundwater residence time and local hydrogeology. Our finding that lithogenic Si dissolution occurs in the freshwater lens and the freshwater–seawater transition zone on Rottnest Island appears to supports the recent inclusion of a marine–submarine groundwater discharge term in the global dSi mass balance. Geologically young carbonate aquifers, such as Rottnest Island, may be an important source of dSi in coastal regions with low riverine input and low oceanic dSi concentrations.

Response of Nitrate Processing to Bio-labile Dissolved Organic Matter Supply Under Variable Oxygen Conditions in a Sandy Beach Seepage Face

Supply of bio-labile dissolved organic matter (DOM) has been assumed to be a key factor for the intensity of nitrate (NO3–) removal in permeable coastal sediments. In the present study, a series of flow through reactor experiments were conducted using glucose as a N-free bio-labile DOM source to permeable sediments from a sandy beach seepage face to identify its effect on benthic NO3– removal. The results revealed a shift from the dominance of NO3– production to removal processes when NO3– input concentration increased from 10 to 80 μM under oxic conditions. Sediment microbiota information suggests that nitrification (e.g., Nitrosomonas and Nitrososphaera) and denitrification (e.g., Marinobacter and Bacillus) were dominant pathways for benthic NO3– production and removal in the studied sediment. Compared with the active response of sediment microbiota to NO3– additions, the supply of glucose (approximately 300 μM final concentration added) did not significantly change the NO3– removal efficiency under aerobic conditions (dissolved oxygen saturation approximately 100%). Similarly, an insignificant increase of NO3– removal rate after glucose amendment of the circulating water was obtained when dissolved oxygen (DO) saturation decreased to approximately 70% in the input solution. When DO at the input solution was decreased to 30% saturation (sub-oxic conditions), the removal rate of NO3– in the group amended with glucose increased, suggesting that glucose stimulated denitrifiers. These results revealed that NO3– removal relied mainly on the anaerobic environment at particle surfaces, with a dependence on the sedimentary organic matter as an electron supplier under bulk aerobic conditions, while the bio-labile DOM was consumed mainly by aerobic respiration instead of stimulating NO3– reduction. However, the respiration triggered by the over-supply of bio-labile DOM reduced the DO in the porewater, likely depressing the activity of aerobic reactions in the permeable sediment. At this point, the benthic microbiota, especially potential denitrifiers, shifted to anaerobic reactions as the key to support nitrogen metabolism. The glucose amendment benefited NO3– reduction at this point, under sub-oxic conditions.

A Methodology for Assessing Groundwater Pollution Hazard by Nitrates from Agricultural Sources: Application to the Gallocanta Groundwater Basin (Spain)

Groundwater pollution by nitrates from agricultural sources is a common environmental issue. In order to support risk analysis, hazard maps are used to classify land uses according to their potential of pollution. The aim of this study is to propose a new hazard index based on nitrogen input and its connection with nitrate concentration in groundwater. The effectiveness of the Nitrogen Input Hazard Index was tested in the Gallocanta Groundwater Basin (Spain), a highly polluted area, declared as a Nitrate Vulnerable Zone. Agricultural data at a plot scale were used to estimate the nitrogen fertilizer requirement of each crop, and the correlation between nitrogen input and nitrate concentration in groundwater was explored. The resulting hazard map allows us to delimit the most hazardous areas, which can be used to implement more accurate nitrate pollution control programs. The index was proven to successfully estimate nitrogen input influence over groundwater nitrate concentration, and to be able to create hazard maps. The criterion used to create categories was empirically based on nitrate concentration thresholds established by the EU Nitrate Directive. The Nitrogen Input Hazard Index may be a useful tool to support risk analyses of agricultural activities in vulnerable areas, where nitrate pollution could endanger human water supply.

Dust Distribution and Emission Modeling (Study Area: Mahshahr Area)

Dust storms are one of the most significant challenges in the Western Asia region in recent years and have intensified because of drought. Emission of dust in a scattered and especially heterogeneous manner has made it difficult to determine the exact effect, so modeling is one of the best possible ways to quantify dust emission. Moreover, to deal with this phenomenon, it is necessary to identify the main and influential factors and, by combining these factors, we can predict dust storms using models. The purpose of this study is to model the distribution and emission of dust in two stormy days on the 26th and 27th of January 2017 in the arid and the hyper-arid region of Mahshahr. For this purpose, coding of each meteorological parameter (section 2.2), dust input concentration parameters, and in MATLAB R2014 software have been made. Also, dust input concentration maps were prepared for the two stormy days in the study area in ARCGIS 9.3 software. Finally, the results were evaluated with WRF model outputs. The efficiency of the developed model was also evaluated based on the hourly data of the dust input concentration for two stormy days in the study area. The evaluation of the model shows the ability of this model to modeling the dust distribution in the study area with high intensity of dust emitted and high accuracy. The R correlation index for the period under study was 0.84, which indicates the high accuracy of the model.

Denitrification in the vadose zone: Modelling with percolating water prognosis and denitrification potential

Transport and transformation processes of nitrogen in the soil are an essential part of understanding the relationship between agricultural input and nitrate (NO3−) concentrations in groundwater. The presented study describes these transformation processes around NO3− degradation at a water catchment in the Lower Rhine Embayment, Germany. Despite intensive agriculture, extracted groundwater at a depth of 21 to 22 m shows unexpectedly very low NO3− levels, below 3 mg/L NO3− for all wells. The local water supplier therefore carried out investigations in this area and generated soil data from 22 representative areas (142 soil samples from 82 drilling meters from the surface to a max. depth of 5.5 m) and groundwater analyses from 17 groundwater monitoring wells (from 3 to 5 m below ground surface). Soil types are predominantly luvisol and gleysol. The substrate in the topsoil is mainly clayey silt; underneath there are mostly medium-grained sands with partial silt intercalations which appear as a separate layer. Based on this dataset, the percolating water residence times and the NO3− leaching potential were calculated in this study. Together with the nitrogen surplus and with the help of reactive transport modelling, the denitrification potential in the vadose zone was simulated. The comparison of simulation results with laboratory-measured data shows a high correlation. Substantial NO3− reduction in the vadose zone was observed: dependent on soil type, reduction capacity and water residence time, up to 25% of the NO3− was reduced here. The applied modelling is considered an improvement in NO3− degradation potential assessment because it considers many relevant variables such as precipitation, soil parameters (grain size, field capacity, available water capacity, coarse fragments) and nitrogen input. Therefore, a transfer to other sites with comparable hydro(geo)logical conditions is possible, also due to relatively easily determinable input data. This assessment of nitrogen degradation in the vadose zone will be a useful tool for NO3− levels forecast in groundwater

Global Stability Analysis of the Model of Series/Parallel Connected CSTRs with Flow Exchange Subject to Persistent Perturbation on the Input Concentration

In this paper, we study the convergence properties of a network model comprising three continuously stirred tank reactors (CSTRs) with the following features: (i) the first and second CSTRs are connected in series, whereas the second and third CSTRs are connected in parallel with flow exchange; (ii) the pollutant concentration in the inflow to the first CSTR is time varying but bounded; (iii) the states converge to a compact set instead of an equilibrium point, due to the time varying inflow concentration. The practical applicability of the arrangement of CSTRs is to provide a simpler model of pollution removal from wastewater treatment via constructed wetlands, generating a satisfactory description of experimental pollution values with a satisfactory transport dead time. We determine the bounds of the convergence regions, considering these features, and also: (i) we prove the asymptotic convergence of the states; (ii) we determine the effect of the presence of the side tank (third tank) on the transient value of all the system states, and we prove that it has no effect on the convergence regions; (iii) we determine the invariance of the convergence regions. The stability analysis is based on dead zone Lyapunov functions, and comprises: (i) definition of the dead zone quadratic form for each state, and determination of its properties; (ii) determination of the time derivatives of the quadratic forms and its properties. Finally, we illustrate the results obtained by simulation, showing the asymptotic convergence to the compact set.

Temporal and spatial variations of organochlorine pesticides (OCPs) and phthalates affecting the quality of water and sediment from Loskop Dam, South Africa

Organochlorine pesticides (OCPs) and phthalates are amongst the most emphasized man-made environmental contaminants, due to their prevalence, persistence and potential to induce adverse effects in organisms. In addition to prevailing industrial and domestic activities, their presence in the environment is exacerbated by leaching from associated materials, run-off and emissions. The Loskop Dam in the Mpumalanga Province, South Africa, is located on the Olifants River, which flows through a hub of industrial and agricultural activities. Research aimed at monitoring the levels of OCPs and phthalate contamination in South Africa, particularly in the Olifants catchment, has been limited and is restricted to short-term monitoring. In this study, the spatial and temporal variations of 21 OCPs and 7 phthalates in water and sediments from Loskop Dam were evaluated over a 3-year period (2015–2017). Annual average OCP levels ranged from 0.013±0.006 to 0.36±0.13 μg/L in water and from below the limit of detection to 2.4±1.2 µg/kg in sediments. Phthalates were present at average concentrations ranging from 0.023±0.041 to 2.1±1.5 μg/L and 20±0.63 to 55±6.9 µg/kg in water and sediments, respectively. The levels of OCPs and phthalates were greatest in autumn, attributed to higher input sources and concentration effects due to lower water levels. Phthalates were present at greater quantities at the inlet, while OCP accumulation was observed at the upper reaches of the dam. This may be an indication of the differences in input sources and translocation of these compounds, related to the topography of the dam and variability in water flow rates. These findings are important in highlighting the environmental and health concerns that may arise in the Olifants catchment area. After considering the outcomes of this study, we propose the implementation of regular and stringent monitoring strategies, which include surveys of OCPs and phthalates for Loskop Dam and similar water systems globally.

ANFIS modelling of effective thermal conductivity of ethylene glycol and water nanofluids for low temperature heat transfer application

Nanofluids have been proven to be promising coolants for heat transfer application due to their superior thermal properties. In the present work, experimental studies were carried out to investigate the thermal conductivity of ethylene glycol (EG) and water mixture (35:65 v/v in ratio) based CuO, Al2O3 and TiO2 nanofluids. The study has considered nanofluid containing nanoparticles in the concentration range of 0.2 to 2 wt%. The effect of nanoparticle concentration on thermal conductivity was investigated in terms of effective thermal conductivity (ratio of thermal conductivity of nanofluid to that of base fluid) at low temperatures (5 to 25 °C). Results indicated significant improvement in thermal conductivity at lower temperature of nanofluids. Enhancement of 6.34%, 4.87% and 3.59% in thermal conductivity was obtained for 2 wt% of concentration at 5 °C for CuO, Al2O3 and TiO2 nanoparticles respectively compared to EG:Water. Correlations for effective thermal conductivity were developed by regression considering two input (temperature, concentration) and three input (temperature, concentration and nanoparticles thermal conductivity) parameters using experimental results. An intelligent model, adaptive neuro-fuzzy inference system (ANFIS) approach was used to model the effective thermal conductivity of nanofluids. ANFIS model performed better than the correlations developed.

A new transfer function model for the estimation of non-point-source solute travel times

The scope of this work is to present a new fast and reliable transfer function model, which simulates the spatio-temporal distribution of non-point-source solutes along the unsaturated zone, suitable to be used at large scales within a web-based Decision Support System. With the assumptions of a) a gravity induced water flow, b) a non-reactive solute and c) a purely convective flow, the model uses the transfer functions, i.e., the travel time (TT) probability density functions, derived from the unsaturated hydraulic conductivity curve k(θ). The output concentration of a solute is simply the convolution of the transfer functions with the input concentrations to the system. A model sensitivity analysis, based on Monte Carlo simulations, was carried out, showing that saturated water content and the tortuosity parameter τ were the parameters that affected the mean TT more. The model was validated against concentration experiments carried out on four large soil columns. Results were really good for all soils, with the best agreement with R2 = 0.97, RMSE = 0.11 and ME = −0.01. Moreover, the outputs obtained applying the model to 46 soil profiles sampled in the Valle Telesina, in Southern Italy, completely characterised from the hydrological point of view, were compared with those obtained from the Richard-based model Hydrus 1D. The result of the comparisons gave a very high correlation coefficient (above 0.8), a mean absolute error between the two models of around 40 days and a percent bias of −16%. Finally, the application of transfer function model to a large spatial extent is presented, to show its possible use for the groundwater vulnerability assessment.

Catalytic thermal decomposition of tetrafluoromethane (CF4): A review

This review summarizes the catalytic-thermal decomposition studies present for tetrafluoromethane (CF4, R-14). CF4 possesses a GWP of 6,630 and has a lifetime of 50,000 years. There are some natural sources of emission present for CF4 but anthropogenic sources are causing an issue. Due to high GWP, it is very important to find sustainable methods to decompose CF4 on a large scale. There are several methods available for the destruction of CF4. Among those methods, the catalytic-thermal decomposition process is one of the most reliable. Its simplicity and lack of harmful by-products make the catalytic-thermal decomposition process a promising method. With the help of a catalyst, decomposition temperature can be reduced. Reduction of temperature makes the process more feasible and economical. There are some limitations to this process such as catalyst poisoning and low input concentration, which need to be resolved.

The XGBoost and the SVM-based prediction models for bioretention cell decontamination effect

Surface water flooding is in a crisis for most large cities of the world. Sponge city is an innovative idea conceptualized designed to cope with urban surface water flooding and other relevant water management issues. Bioretention cell is one of the most important green drainage facilities in the construction of sponge cities, with the function of storing rainwater and reducing surface pollution. In this study, a non-vegetative bioretention cell has been constructed, and experimental data on inlet water and outlet water concentrations are obtained through a long period of operation. The XGBoost and the SVM methods are employed to simulate the water quality model based on the input and output sewage concentration of the bioretention cell. The experiment results show that the XGBoost model has a better generalization ability than the SVM model to improve the prediction accuracy with higher decontamination effect. The proposed work can provide a significant guide to the watershed planning of water reuse system.

Phenol Sulfonic Acid Oxidation in aqueous solution by UV, UV/H2O2 and Photo-Fenton Processes

In this study, advanced oxidation processes (UV, UV/H2O2, UV/H2O2/Fe(II) and UV/H2O2/Fe(III)) were investigated in lab-scale experiments for degradation of phenol sulfonic acid (PSA) in aqueous solution. The study showed that the UV/H2O2 process has removal percentage 90.9, 93.0 and 94.4 for neutral, basic and acidic conditions in 20 minutes respectively. The experimental results showed that the optimum conditions were obtained at a pH value of 3, with 4 mmol/1 H2O2, and 0.25 mmol/1 Fe(II) for the UV/H2O2/Fe(II) system and 6 mmol/l H2O2 and, 0.4 mmol/1 Fe(III) for the UV/H2O2/Fe(III) system. The reaction was influenced by the pH, the input concentration of H2O2 and the amount of the iron catalyst and the type of iron salt. As for the UV processes, UV/H2O2 showed the highest degradation rate under acidic conditions

NGS and NanoString Platforms Play Complementary Role in Bedside Advanced Heart Failure Outcome Prediction Test Development

<h3>Purpose</h3> In order to create a clinical assay that preoperatively predicts 1-year survival status of AdHF patients following surgical/interventional therapies and to select the appropriate commercial platform, we compared the properties of Next Generation Sequencing (NGS) to NanoString (NS). <h3>Methods</h3> 8ml of blood was collected in CPT tubes from 25 AdHF patients (11 heart failure control, 4 mechanical circulatory support surgery, and 10 heart transplant surgery) at UCLA Medical Center 2015-2016. Purified RNA samples were aliquoted in two sets: one was processed using NGS transcriptome analysis (Illumina HiSeq 2500) and compared to 770 genes represented on NS pre-existing PanCancer IO 360 Gene Expression research panel. Prior to statistical analysis, expression values were log transformed. Pearson correlation coefficients were computed for each sample. Gene expression values were compared between NS and NGS across the set of matched genes and for each of the matched genes across the set of samples. Genes were grouped by average NGS expression, and the NS-NGS correlation for each group was computed. <h3>Results</h3> Out of 770 genes, 734 overlapped between both platforms and showed high intrasample correlation (R^2 = 0.82). Genes with higher expression demonstrated higher correlation across both platforms (Figure). NS demonstrated high <b>robustness:</b> Gene signature scores were similar across different RNA input concentrations, cartridges, and outcomes; <b>sensitivity:</b> Probe counts between 100 and 500 detected and quantified. The RNA input of 100 ng yielded the most precise result and were used for downstream analysis; and <b>reproducibility:</b> Technical replicates with equal concentration (100ng input) showed extremely high correlation (R^2 > 0.99), thus demonstrating high reproducibility. <h3>Conclusion</h3> Both platforms have meaningful, complementary roles, NGS for discovery and NanoString for commercialization and can be used for AdHF-biomarker test development.