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Summary: The formation of Li4SiO4 (LSO) coating layer on LiNi0.88Co0.05Mn0.07O2 (LNCM) was achieved by incorporating a new tetraethyl orthosilicate (TEOS)‐dropping coating method. This concept includes the hydrolysis reaction of TEOS on the surface of Ni0.88Co0.05Mn0.07(OH)2 and the subsequent calcination process with lithium source to obtain LSO‐coated LNCM cathode materials successfully during the calcination process. This method provides the driving force for the formation of a more uniform and thin coating layer compared with the traditional wet‐chemical coating method. The bare LNCM and LSO‐coated LNCM showed similar capacity retention rates during room temperature (25°C) cycling, but the capacity retention of LSO‐LNCM (81.6% after 100 cycles) for the cycling test at elevated temperature was significantly increased compared with bare LNCM (63.69% after 100 cycles). Additionally, the Li‐ion accessibility of the coated LNCM electrode was improved by the existence of the Li‐containing coating materials, and the results of analysis by the galvanostatic intermittent titration technique (GITT) confirmed the better Li‐ion diffusivity of the coated sample. These results indicate the high possibility of this novel coating method for application in various materials for developing secondary batteries. [ABSTRACT FROM AUTHOR]

Summary: High‐Ni layered‐oxide cathodes are the most prospective cathode materials for next‐generation Li‐ion batteries (LIBs) in electric vehicles (EVs) owing to their high specific capacity. However, High‐Ni layered‐oxide cathode materials exhibit inferior cyclability and low thermal stability owing to the side reaction between Ni4+ and the electrolytes. To solve these surface‐related problems, we proposed a strategy for forming LiNbO3 (LNO)—with outstanding thermal stability and ionic conductivity—on a Ni‐rich layered‐oxide surface using polydopamine (PDA). The PDA formed on the transition metal hydroxide surface has copious catechol OH groups, which attract the Nb ions in the solution to form a LNO coating layer during the calcination process. The LiNi0.8Co0.1Mn0.1O2 (pristine LNCM) electrode experiences enormous degradation when cycled after being subjected to severe conditions—such as a full charge and a 60°C storage test—but the LiNbO3‐coated LNCM (LNO‐LNCM) electrode exhibits particularly stable cycling performance. Furthermore, differential scanning calorimetry (DSC) results exhibited that the LNO coating notably ameliorated the thermal stability of the cathode material. As a result, our experimental results suggest that the development of cathode materials that can withstand greatly oxidized states and high‐temperature environments is achievable. [ABSTRACT FROM AUTHOR]

The biodiesel containing fatty acid methyl esters (FAMEs) are blended with refined diesel products. Here, we evaluate relative FAME composition ratio as a potential index to discriminate the pollution origin in diesel-contaminated soil. Artificially contaminated soil was prepared to mimic the release of petroleum products using four different refined diesels; in addition, the contaminated soil was put under natural weathering conditions. The variations in the relative FAME composition ratio was compared with those of the corresponding diesel origin using principal component analysis (PCA) for 60 days. All soil samples could be classified into four groups according to diesel origin using two principal components. The proposed method can be used to discriminate the specific diesel pollution origin in contaminated soils. [ABSTRACT FROM AUTHOR]

In order to solve large-scale lasso problems, screening algorithms have been developed that discard features with zero coefficients based on a computationally efficient screening rule. Most existing screening rules were developed from a spherical constraint and half-space constraints on a dual optimal solution. However, existing rules admit at most two half-space constraints due to the computational cost incurred by the half-spaces, even though additional constraints may be useful to discard more features. In this paper, we present AdaScreen, an adaptive lasso screening rule ensemble, which allows to combine any one sphere with multiple half-space constraints on a dual optimal solution. Thanks to geometrical considerations that lead to a simple closed form solution for AdaScreen, we can incorporate multiple half-space constraints at small computational cost. In our experiments, we show that AdaScreen with multiple half-space constraints simultaneously improves screening performance and speeds up lasso solvers. [ABSTRACT FROM AUTHOR]

Genome-wide association studies have discovered a large number of genetic variants associated with complex diseases such as Alzheimer’s disease. However, the genetic background of such diseases is largely unknown due to the complex mechanisms underlying genetic effects on traits, as well as a small sample size (e.g., 1000) and a large number of genetic variants (e.g., 1 million). Fortunately, datasets that contain genotypes, transcripts, and phenotypes are becoming more readily available, creating new opportunities for detecting disease-associated genetic variants. In this paper, we present a novel approach called “Backward Three-way Association Mapping” (BTAM) for detecting three-way associations among genotypes, transcripts, and phenotypes. Assuming that genotypes affect transcript levels, which in turn affect phenotypes, we first find transcripts associated with the phenotypes, and then find genotypes associated with the chosen transcripts. The backward ordering of association mappings allows us to avoid a large number of association testings between all genotypes and all transcripts, making it possible to identify three-way associations with a small computational cost. In our simulation study, we demonstrate that BTAM significantly improves the statistical power over “forward” three-way association mapping that finds genotypes associated with both transcripts and phenotypes and genotype-phenotype association mapping. Furthermore, we apply BTAM on an Alzheimer’s disease dataset and report top 10 genotype-transcript-phenotype associations. [ABSTRACT FROM AUTHOR]

• An advanced ensemble smoother suitable for multi-source identification is proposed. • Multiple contaminant sources and 3D permeability fields are successfully estimated. • Inversion accuracy improves as the intensity of variable-density flow increases. Groundwater contamination is an exacerbating global issue that severely threatens human health. Subsurface remediation thus has gained increased interest in recent years. To effectively remediate subsurface contaminated sites, one needs to identify the locations of contaminant sources and characterize contaminant spreading. Groundwater contamination is often driven by multiple contaminant sources, making source identification problems challenging. Further, when the densities of dissolved contaminants and ambient groundwater differ, the resultant variable-density flows add complexity to the task of source identification. However, most previous studies are limited to a single source identification in a two-dimensional aquifer. This study presents a novel inversion method based on ensemble smoothing that identifies the locations of multiple contaminant sources in three-dimensional heterogeneous aquifer systems. A new covariance localization algorithm based on a clustering method is integrated into the inversion method, which improves the accuracy of multi-source identification. Using the proposed inversion framework, we successfully estimate the locations of multiple contaminant sources and three-dimensional permeability fields utilizing pressure and concentration data from monitoring wells. Further, we investigate and elucidate the effects of aquifer heterogeneity and variable-density flows on multiple source identification. We find that variable-density flow increases the data information contents and thus improves the inversion accuracy. This is the first-time demonstration of the effects of variable-density flow on the inversion accuracy of multi-source identification in three-dimensional heterogeneous aquifer systems. [ABSTRACT FROM AUTHOR]

Genome-wide association studies have revealed individual genetic variants associated with phenotypic traits such as disease risk and gene expressions. However, detecting pairwise interaction effects of genetic variants on traits still remains a challenge due to a large number of combinations of variants (∼1011 SNP pairs in the human genome), and relatively small sample sizes (typically <104). Despite recent breakthroughs in detecting interaction effects, there are still several open problems, including: (1) how to quickly process a large number of SNP pairs, (2) how to distinguish between true signals and SNPs/SNP pairs merely correlated with true signals, (3) how to detect nonlinear associations between SNP pairs and traits given small sample sizes, and (4) how to control false positives. In this article, we present a unified framework, called SPHINX, which addresses the aforementioned challenges. We first propose a piecewise linear model for interaction detection, because it is simple enough to estimate model parameters given small sample sizes but complex enough to capture nonlinear interaction effects. Then, based on the piecewise linear model, we introduce randomized group lasso under stability selection, and a screening algorithm to address the statistical and computational challenges mentioned above. In our experiments, we first demonstrate that SPHINX achieves better power than existing methods for interaction detection under false positive control. We further applied SPHINX to late-onset Alzheimer's disease dataset, and report 16 SNPs and 17 SNP pairs associated with gene traits. We also present a highly scalable implementation of our screening algorithm, which can screen ∼118 billion candidates of associations on a 60-node cluster in <5.5 hours. [ABSTRACT FROM AUTHOR]

Three commercial organoclays were evaluated as media for a variably permeable reactive barrier (VPRB) to manage coal-tar creosote, a non-aqueous-phase liquid (NAPL) consisting primarily of polynuclear aromatic hydrocarbons (PAHs). Organoclays and organoclay-sand mixtures having at least 25% organoclay had NAPL conductivities of less than 10-10 m/s, whereas hydraulic conductivities to water were on the order of 0.001 m/s. Water migration was negligible in organoclays solvated with NAPL, but PAHs were released to the aqueous phase when the solvated clay contacted deionized water. Sorption isotherms for aqueous-phase PAHs are convex upward within the range of concentrations of environmental interest, and greater sorption occurs when the aqueous phase contains multiple PAHs. In column tests, breakthrough occurred for only naphthalene (lowest Kow) and for only one organoclay (lowest organic carbon content) for tests on 100% organoclay and organoclay-sand mixtures conducted for 208-276 pore volumes of flow (PVF). Breakthrough predicted with solute transport analyses conducted using batch isotherm parameters as input occurred later than observed in the column test because isotherm models fit to the batch test data overpredicted sorption at low concentrations. The findings indicate that organoclays should be effective media for VPRBs to manage creosote NAPL and associated PAHs dissolved in groundwater. They block NAPL advection, readily permit the flow of water with dissolved PAHs, and sorb dissolved PAHs from water flowing through the clays. [ABSTRACT FROM AUTHOR]

Abstract: Partitioning tracer method has been studied as an effective technique for estimating the light nonaqueous-phase liquid (LNAPL) contamination in the subsurface. This study is for investigating the effect of soil organic contents on the LNAPL quantification using partitioning tracer method. The sorption characteristics of alcohol tracers to the soils having different organic carbon contents were evaluated by sorption isotherm experiments. In the column tests, the soils were contaminated with jet-fuel and the average saturations of residual jet-fuel were estimated by partitioning tracer method and compared with that by the volume measurement. The sorption results indicated that considerable amount of 4-methyl-2-pentanol and hexanol could be sorbed to the soils and the sorption amount of 2-ethyl-1-butanol was relatively smaller than those of the other alcohol tracers. The column experiments demonstrated that the accuracy of quantification for the jet-fuel by partitioning tracer method should decrease with increasing the soil organic carbon contents. However, the accuracy could be enhanced by considering the sorption of tracer to the soils, especially for the tracer of 2-ethyl-1-butanol. [ABSTRACT FROM AUTHOR]

Abstract: Landmark multidimensional scaling (LMDS) uses a subset of data (landmark points) to solve classical multidimensional scaling (MDS), where the scalability is increased but the approximation is noise-sensitive. In this paper we present an LMDS ensemble where we use a portion of the input in a piecewise manner to solve classical MDS, combining individual LMDS solutions which operate on different partitions of the input. Ground control points (GCPs) that are shared by partitions considered in the ensemble, allow us to align individual LMDS solutions in a common coordinate system through affine transformations. We incorporate priors into combining multiple LMDS solutions such that the weighted averaging by priors improves the noise-robustness of our method. Our LMDS ensemble is much less noise-sensitive while maintaining the scalability and the speed of LMDS. Experiments on synthetic data (noisy grid) and real-world data (similar image retrieval) confirm the high performance of the proposed LMDS ensemble. [Copyright &y& Elsevier]

Previous studies have revealed that the application of zero-valent iron (ZVI) in reducing nitrate is limited by ammonium production and the requirement for adequate pH control. The current study focused on developing a new material potentially applicable in permeable reactive barriers, which can reduce nitrate without ammonium release under unbuffered pH. The new material, referred to as ZanF, is derived from zeolite modified by Fe(II), followed by borohydride reduction. The pseudo-first-order rate constant (kobs) of ZanF in the early period of nitrate reduction was 10 times higher than that of the ZVI used in this study. However, the kobs of ZanF decreased in the reaction period that followed. Even though both ZVI and ZanF produced ammonium as a product of nitrate reduction, ZanF removed it to below detection limits via adsorption, whereas ZVI did not remove it to any significant extent. ZanF maintained its high reactivity even under an initial pH of 6.2 without buffer. The higher ZanF/solution ratio increased the removal rate of ZanF as well as the removal efficiency. [ABSTRACT FROM AUTHOR]

• Variable-density flow controls the coupling between pressure and concentration data. • The coupling effect is formally quantified by the analysis of mutual information. • We analyze the value-of-information of joint pressure-concentration inversion. • The advantage of joint inversion decreases as the coupling effect increases. • The amount of shared information decreases as permeability heterogeneity increases. Predicting variable-density flow and transport in aquifers is critical for the management of many coastal saline aquifers. Accurate characterization of hydrogeological parameters is critical for prediction, and the characterization is often conducted by assimilating data into models. However, few studies have investigated the underlying physics controlling the value-of-information (VOI) of data for aquifer characterization. In this study, we show how a greater understanding of the underlying physics controlling pressure and concentration data coupling can lead to improved characterization. In variable-density flow, the key physics that controls the VOI of pressure and concentration data is the non-linear coupling between flow and transport via fluid density which causes the pressure field to experience transient changes according to the evolution of salinity distribution. We first demonstrate the coupling between pressure and concentration data using information theory, and then systematically investigate how the variable-density flow impacts the VOI of these data in relation to permeability estimation. Using an ensemble Kalman filter, we estimate the permeability field of saline aquifer systems in two scenarios of data usage: pressure data only, and pressure and concentration data jointly. This study demonstrates that, regardless of the data usage scenario, the maximum VOI of data is obtained when free convection and forced convection are balanced. We further show that the advantage of joint inversion of pressure and concentration data decreases as the coupling effect between flow and transport increases. Finally, we study how the level of permeability field heterogeneity affects the coupling, which in turn controls VOI of pressure and concentration data. [ABSTRACT FROM AUTHOR]

A letter to the editor on mixture of distributions indel locator (MoDIL) is presented.

A new method for identifying the petroleum products in contaminated soils is presented, which characterizes the unresolved complex mixture (UCM) hump in the baseline of gas chromatograph (GC) data. The UCM hump identified in soil data was fitted to the Gaussian function, and characterized according to the time for the maximum point ( T UCM ) and the width of the hump ( w ). Experimental results showed that a UCM hump should be clearly observed in soils when contaminated with petroleum, and that soils contaminated with kerosene, diesel, or some lubricating oils estimated herein should present different characteristic values of T UCM and w . Even though the environmental weathering of contaminated soils under evaporative conditions might cause variations in these characteristic values, they converged to specific constants depending on the product. The method could also differentiate between multiple petroleum contaminants in soil. Feasibility was evaluated using soils from a military oil storage site that was closed in 1970. The soil contaminants identified by the proposed method corresponded to the historical storage records, suggesting that the UCM hump characterization method could have strong potential in environmental forensics for differentiating products in petroleum-contaminated soils. [ABSTRACT FROM AUTHOR]

In this study, the organic components were identified that are mainly responsible for the formation of disinfection byproducts (DBPs) and for the biostability of urban surface water. The compositional distribution of dissolved organic matter (DOM) was strongly associated with the potential for both DBP formation and bacterial growth. Further evaluation was carried out (1) to compare the potential for DBP formation upon chlorination of treated water, (2) to determine the biostability that might result from minimizing assimilable organic carbon (AOC), and (3) to use laboratory-scale soil-column experiments to compare the effects of removal of trace organic chemicals (TOrCs) between managed aquifer recharge (MAR) hybrid systems (such as bank filtration followed by artificial recharge and recovery: ARR), and ozonation followed by ARR. Our fractionation and removal methods provided useful insights into the removal of problematic organic components using MAR hybrid systems. Pretreatment with a small amount of ozone (∼0.7 mg-O 3 mg-C −1 ) resulted in improved ARR performance, especially from removing organic acids from DOM, which substantially decreased the potential for DBP formation, while the robust removal of AOC was attributed to a significant decrease in non-acidic and more hydrophilic fractions during soil passage. Both pretreatments used in this study were effective in the removal of selected TOrCs, but carbamazepine was persistent during soil passage. The pretreatment, which used ozonation before ARR, significantly enhanced the removal of carbamazepine; therefore, ozonation followed by ARR is considered an effective way to enhance removal of persistent compounds. [ABSTRACT FROM AUTHOR]

Motivation: As many complex disease and expression phenotypes are the outcome of intricate perturbation of molecular networks underlying gene regulation resulted from interdependent genome variations, association mapping of causal QTLs or expression quantitative trait loci must consider both additive and epistatic effects of multiple candidate genotypes. This problem poses a significant challenge to contemporary genome-wide-association (GWA) mapping technologies because of its computational complexity. Fortunately, a plethora of recent developments in biological network community, especially the availability of genetic interaction networks, make it possible to construct informative priors of complex interactions between genotypes, which can substantially reduce the complexity and increase the statistical power of GWA inference.Results: In this article, we consider the problem of learning a multitask regression model while taking advantage of the prior information on structures on both the inputs (genetic variations) and outputs (expression levels). We propose a novel regularization scheme over multitask regression called jointly structured input–output lasso based on an ℓ1/ℓ2 norm, which allows shared sparsity patterns for related inputs and outputs to be optimally estimated. Such patterns capture multiple related single nucleotide polymorphisms (SNPs) that jointly influence multiple-related expression traits. In addition, we generalize this new multitask regression to structurally regularized polynomial regression to detect epistatic interactions with manageable complexity by exploiting the prior knowledge on candidate SNPs for epistatic effects from biological experiments. We demonstrate our method on simulated and yeast eQTL datasets.Availability: Software is available at http://www.sailing.cs.cmu.edu/.Contact: epxing@cs.cmu.edu [ABSTRACT FROM PUBLISHER]

[Display omitted] • The homogeneous coating layer is formed using electrostatic force of the polymer. • Li 3 VO 4 -coated LiNi 0.5 Mn 1.5 O 4 are synthesized simultaneously by a single calcination step. • Nanoscale Li 3 VO 4 coating improves the LiNi 0.5 Mn 1.5 O 4 performance. • Li 3 VO 4 coating layer increases Li-ion access and conductivity. • Li 3 VO 4 layer effectively suppresses side reactions at elevated temperatures. One of the most promising high voltage cathode materials for application in lithium ion batteries (LIBs), the 5 V spinel LiNi 0.5 Mn 1.5 O 4 , faces electrode/electrolyte decomposition at high voltage, rendering commercial application difficult. To overcome these obstacles, this study proposes a method for adsorbing vanadium anion complexes on the surface of Ni 0.25 Mn 0.75 (OH) 2 using cationic polymers and calcination them with LiOH to form LiNi 0.5 Mn 1.5 O 4 with a uniform nano-Li 3 VO 4 coating layer. The uniform nano-Li 3 VO 4 coating layer prepared by the above method promotes transfer of lithium ions and protects active material from electrolyte corrosion, thereby obtaining a particularly stable electrochemical performance under severe operating conditions such as high temperatures. Electrochemical tests show that the Li 3 VO 4 -coated LiNi 0.5 Mn 1.5 O 4 demonstrates a high discharge capacity and at the cycling test after storage test at 60 °C, the Li 3 VO 4 -coated LiNi 0.5 Mn 1.5 O 4 shows higher capacity retention than pristine LiNi 0.5 Mn 1.5 O 4 ; this can be attributed to the coating that acts as a protective layer. [ABSTRACT FROM AUTHOR]

The anomalous (i.e., non-Fickian) transport characteristics (e.g., early arrival/long tailing and other non-Gaussian plume properties) make it challenging to apply classical transport theories to the transport and retention of microplastics in soil due to their heterogeneity. This overview attempts 1) to delineate the previous studies on the transport of colloids and MPs, which used the recently developed analytical devices (e.g., microfluidics and micro-CT) and process-based (e.g., lattice Boltzmann method (LBM) and pore network modeling (PNM)) or data-driven models (e.g., machine learning (ML) techniques) and 2) to provide future directions for bridging the pore- and continuum-scale properties. Although the LBM and PNM offer significant advantages in depicting particle transport at the pore scale, their employment at larger scales is hindered by computational demands. Nonetheless, applying these methods to generate datasets for ML techniques is anticipated to provide a robust tool for an accurate and rapid continuum-scale microplastics transport model. [Display omitted] • We outlined recent particle transport studies for various scales and model types. • Recent advancements enabled microscopic observations and simulations. • Machine learning enhanced the prediction performance for particle transport models. • A multiscale, hybrid model could overcome the limitations of the individual model. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pilot-scale simulated ASR system injecting river water was stably operated. • Seasonal variations in organics and soil microbiome were evaluated for one year. • Organic compounds in soil and effluent water were maintained for long-term periods. • Soil microbial communities were shifted with process operation and sample location. • Diverse soil microbes degraded the organics during the ASR storage period. Soil microbiome is responsible for crucial biochemical reactions by interacting with organic compounds in the injection wells in aquifer storage and recovery (ASR) processes. This study investigated seasonal variations in organic compounds and microbial communities in a simulated ASR system. For this purpose, eleven pilot-scale soil columns were operated in ASR mode over 13 months. River water was intermittently fed into the simulated ASR system after sedimentation pretreatment. As a result, the sand ratios in soil texture were slightly increased from 93.2-93.4 % to 96.6–98.1 % while the total organic carbon content in the soil was accumulated and maintained at < 0.2 % during the ASR operation. During the sedimentation process, 9–31 % of dissolved organic carbon (DOC) was removed in the water, while during the storage in the soil column, the DOC in water was fluctuated. However, the DOC concentration (less than 4 mg/L) in the effluent was stably maintained until the end of operational periods. High-throughput sequencing results showed that the predominant phylum was Proteobacteria. Interestingly, at the species level, the microbial community structure clearly shifted with elapsed time and column location; various organic degrading soil microbiome having different physiological characteristics (e.g., oxygen, substrate, and temperature) became predominant. Outcomes of this study suggest that soil microbiome can facilitate the establishment of stable ASR processes for river water treatment by contributing to bioattenuation. [ABSTRACT FROM AUTHOR]

Evaluating and predicting the natural attenuation capacity (AC) of a vadose zone is essential for determining groundwater vulnerability to contamination from upper sources. However, it remains unclear how the physicochemical properties of vadose zone soils affect AC owing to their complexity and spatial heterogeneity. In this study, we developed a regression model for estimating the AC of a vadose zone against diesel using datasets from different soils with a wide range of physicochemical properties. Among the 17 properties, six (i.e., organic matter (OM), total phosphorous (TP), coefficient of uniformity, particle size (D 30), van Genuchten's n, saturation degree (SD)) were selected as primary regressors. The results indicate that biogeochemical factors, including OM and TP, have decisive effects on the AC. Finally, the regression model was expanded to a GIS-based spatial model and applied to Namyangju, Korea using the index-overlay method. The produced AC map showed a nonmonotonic decrease along the depth, and the areas closer to the water bodies generally represented low AC values, most likely due to the lower OM, TP, and higher SD. This study provides an empirical basis for future research initiatives for spatial and temporal AC dynamics, which complements conventional intrinsic groundwater vulnerability models such as DRASTIC. [Display omitted] • Diesel attenuation capacity (AC) was predicted from multiple linear regression. • Biogeochemical factors have decisive effects on the AC. • AC prediction was expanded to the spatial model using the overlay-index method. • Produced AC map showed a non-monotonic decrease along the depth. • Areas closer to the water bodies generally represented low AC values. [ABSTRACT FROM AUTHOR]

Arsenic (As) is a widespread environmental contaminant that poses a significant threat to ecosystems and human health. Although previous studies have qualitatively revealed the effects of individual soil properties on the transport and fate of As in the vadose zone, their integrated impacts remain obscure. Moreover, studies investigating the retardation factor therein, which is a key parameter for comprehending As transport in the vadose zone, are extremely limited. In this study, we investigated the interplay of soil properties with As transport and retention within the vadose zone, while focusing on the retardation factor of As. We employed steady-state unsaturated water-flow soil column experiments coupled with a mobile–immobile model and multiple linear regression analysis to elucidate the dependence of As retardation factors on the soil properties. In the mobile water zone, iron and organic matter contents emerged as the two most influential properties that impedes As mobility. Whereas, in the immobile water zone, the coefficient of uniformity and bulk density were the most influential factors that enhanced As retention. Finally, we derived an empirical equation for calculating the As retardation factors in each zone, offering a valuable tool for describing and predicting As behavior to protect the groundwater resources underneath. [Display omitted] • Dual-porosity characteristics resulted in anomalous transport of As in vadose zone. • Typical soil properties were used to estimate the As retardation in vadose zone. • Iron and organic matter contents were the major factors in the mobile water zone. • Uniformity coefficient and bulk density were the key factors in the immobile water. [ABSTRACT FROM AUTHOR]

• Gliomas grading is performed with MRI and is important for treatment and prognosis. • A robust network to handle missing MRI modalities is proposed. • Our network outperformed existing methods. Gliomas are graded using multimodal magnetic resonance imaging, which provides important information for treatment and prognosis. When modalities are missing, the grading is degraded. We propose a robust brain tumor grading model that can handle missing modalities. Our method was developed and tested on Brain Tumor Segmentation Challenge 2017 dataset (n = 285) via nested five-fold cross-validation. Our method adopts adversarial learning to generate the features of missing modalities relative to the features obtained from a full set of modalities in the latent space. An attention-based fusion block across modalities fuses the features of each available modality into a shared representation. Our method's results are compared to those of two other models where 15 missing-modality scenarios are explicitly considered and a joint training approach with random dropouts is used. Our method outperforms the two competing methods in classifying high-grade gliomas (HGGs) and low-grade gliomas (LGGs), achieving an area under the curve of 87.76% on average for all missing-modality scenarios. The activation maps derived with our method confirm that it focuses on the enhancing portion of the tumor in HGGs and on the edema and non-enhancing portions of the tumor in LGGs, which is consistent with prior expertise. An ablation study shows the added benefits of a fusion block and adversarial learning for handling missing modalities. Our method shows robust grading of gliomas in all cases of missing modalities. Our proposed network might have positive implications in glioma care by learning features robust to missing modalities. [ABSTRACT FROM AUTHOR]

The effects of extreme geochemical conditions on microbial community composition were investigated for two distinct sets of sediment samples collected near weathered mine tailings. One set (SCH) showed extraordinary geochemical characteristics: As (6.7–11.5%), Pb (1.5–2.1%), Zn (0.1–0.2%), and pH (3.1–3.5). The other set (SCL) had As (0.3–1.2%), Pb (0.02–0.22%), and Zn (0.01–0.02%) at pH 2.5–3.1. The bacterial communities in SCL were clearly different from those in SCH, suggesting that extreme geochemical conditions affected microbial community distribution even on a small spatial scale. The clones identified in SCL were closely related to acidophilic bacteria in the taxa Acidobacterium (18%), Acidomicrobineae (14%), and Leptospirillum (10%). Most clones in SCH were closely related to Methylobacterium (79%) and Ralstonia (19%), both well-known metal-resistant bacteria. Although total As was extremely high, over 95% was in the form of scorodite (FeAsO 4 ·2H 2 O). Acid-extractable As was only ∼118 and ∼14 mg kg −1 in SCH and SCL, respectively, below the level known to be toxic to bacteria. Meanwhile, acid-extractable Pb and Zn in SCH were above toxic concentrations. Because As was present in an oxidized, stable form, release of Pb and/or Zn (or a combination of toxic metals in the sediment) from the sediment likely accounts for the differences in microbial community structure. The results also suggest that care should be taken when investigating mine tailings, because large differences in chemical/biological properties can occur over small spatial scales. [ABSTRACT FROM AUTHOR]

Abstract: The grid-net system estimating the electrical conductivity changes was evaluated as a potential detection system for the leakage of diesel fuel and landfill leachate. Aspects of electrical conductivity changes were varied upon the type of contaminant. The electrical conductivity in the homogeneous mixtures of soil and landfill leachate linearly increased with the ionic concentration of pore fluid, which became more significant at higher volumetric water contents. However, the electrical conductivity in soil/diesel fuel mixture decreased with diesel fuel content and it was more significant at lower water contents. The electrode spacing should be determined by considering the type of contaminant to enhance the electrode sensitivity especially when two-electrode sensors are to be used. The electrode sensitivity for landfill leachate was constantly maintained regardless of the electrode spacings while that for the diesel fuel significantly increased at smaller electrode spacings. This is possibly due to the fact that the insulating barrier effect of the diesel fuel in non-aqueous phase was less predominant at large electrode spacing because electrical current can form the round-about paths over the volume with relatively small diesel fuel content. The model test results showed that the grid-net detection system can be used to monitor the leakage from waste landfill and underground storage tank sites. However, for a successful application of the detection system in the field, data under various field conditions should be accumulated. [Copyright &y& Elsevier]

In natural environments, the fate and migratory behavior of metalloid contaminants such as antimony (Sb) significantly depend on the interfacial reactivity of mineral surfaces. Although boehmite (γ-AlOOH) is widely observed in (sub)surface environments, its underlying interaction mechanism with Sb oxyanions at the molecular scale remains unclear. Considering Sb-contaminated environmental conditions in this study, we prepared boehmite under weakly acidic conditions for use in the systematic investigation of interfacial interactions with Sb(III) and Sb(V). The as-synthesized boehmite showed a nanorod morphology and comprised four crystal facets in the following order: 48.4% (010), 27.1% (101), 15.0% (001), and 9.5% (100). The combined results of spectroscopic analyses and theoretical calculations revealed that Sb(III) formed hydrogen bonding outer-sphere complexation on the (100), (010), and (001) facets and that Sb(V) preferred to form bidentate inner-sphere complexation via mononuclear edge-sharing configuration on the (100), (001), and (101) facets and binuclear corner-sharing configuration on the (010) facet. These findings indicate that the facet-mediated thermodynamic stability of the surface complexation determines the interaction affinity toward the Sb species. This work is the first to document the contribution of boehmite to (sub)surface media, improving the ability to forecast the fate and behavior of Sb oxyanions at mineral–water interfaces. [Display omitted] • Interfacial interaction between boehmite nanorods (BNRs) and Sb(III/V) was studied. • XAS and DFT analyses show a molecular-scale interaction mechanism. • Affinity of BNRs was determined by energy-based geometric structures of Sb(III/V). • The (100), (010), and (001) facets preferred to form hydrogen bonding for Sb(III). • Four facets were functional to form a bidentate inner-sphere complex for Sb(V). [ABSTRACT FROM AUTHOR]

Aquifer storage and recovery (ASR) is a promising approach for managing water resources that enhances water quality through biogeochemical reactions occurring within aquifers. Iron (hydr)oxides, which are the predominant metallic oxides in soil, play a crucial role in degrading dissolved organic carbon (DOC), primarily through a process known as dissimilatory iron reduction (DIR). However, the efficiency of this reaction varies depending on the mineralogy and composition of the aquifer, and this understanding is essential for adequate water quality in ASR. The objective of this study is to investigate the impact of iron (hydr)oxide on acetate, as an organic carbon source, attenuation during the ASR. To achieve this, three sets of laboratory sediment columns were prepared, each containing a different type of iron (hydr)oxide minerals: ferrihydrite, goethite, and hematite. Following an acclimation period of 28 days to simulate the microcosm within an aquifer, the columns were continuously supplied with the simulated river water spiked with acetate (DOC 40–60 mg L−1), and the acetate concentration in the effluent was monitored. The result revealed that the column containing ferrihydrite achieved 97% acetate attenuation through DIR with anoxic conditions (DO < 0.1 mg L−1), while the goethite and hematite columns exhibited limited attenuation rates of 40 and 50%, respectively. Furthermore, the efficiency of acetate attenuation in the ferrihydrite columns increased with the content of ferrihydrite but experienced a rapidly declined at higher contents (3–4%), possibly due to the partial conversion of ferrihydrite to goethite as a result of the interaction between ferrihydrite and the Fe(II) produced during DIR. Additionally, an analysis of the microbial community demonstrated that microorganisms known to possess the ability to reduce iron (hydr)oxides under anaerobic conditions were abundant in the ferrihydrite columns. [Display omitted] • DOC attenuation during the ASR was investigated with iron mineralogy and contents. • Ferrihydrite is the most efficient iron mineral for DOC attenuation via DIR. • At high ferrihydrite contents (>3%), efficiency declines due to Fe(II) intervention. • Ferrihydrite transforms into goethite upon the injection of DOC-reach surface water. • Findings could be beneficial for selecting optimal sites for ASR application. [ABSTRACT FROM AUTHOR]

Water and wastewater treatment plants (WWTPs) receive various types of microplastics (MPs), with fibers and fragments being dominant shapes. Here we investigated the removal behavior and transformation of MPs (polypropylene and polyethylene terephthalate fibers and fragments) in simulated water and wastewater treatment units, including activated sludge process, coagulation, sand filtration, and advanced oxidation/disinfection. Sand filtration demonstrated the highest average efficiency in removing MPs (98 %), followed by activated sludge process (61 %) and coagulation (55 %), which was associated with their physicochemical properties (shape, size, density, surface functional groups, etc). In activated sludge process and coagulation, the polymer type had a greater impact on the removal of MPs than the particle shape, while in sand filtration, the particle shape played a more important role. When subjected to the long-term operation and backwashing of sand filters, approximately 15 % of the initially filtered fragments broke through the sand media, with nearly no fibers escaping. UV-based advanced oxidation and chlorination induced the leaching of dissolved organic matters with different molecular characteristics from fragment MPs, resulting in varying levels of cytotoxicity and bacterial toxicity. Our study provides important information for predicting the fate of MPs and mitigating their impacts in WWTPs. [Display omitted] This study fills the important knowledge gap on the fate of fiber- and fragment-shaped microplastics (MPs) commonly found in water, through a systematic investigation of their removal and transformation in water and wastewater treatment processes. Although the removal efficiency of MPs was greatly varied by their shape and polymer type in activated sludge treatment, coagulation, and sand filtration steps, an overall removal of MPs was high under streams of those treatment processes. Nevertheless, some MPs, particularly fragment-type ones, could escape the former stages and release toxic organic leachates towards bacteria and human cells during chemical oxidation or disinfection. • The properties of MPs had great impact on their removal along treatment process. • Sand filter showed higher MP removal than activated sludge process or coagulation. • In total, about 40 % of MPs was retained in sludge during activated sludge process. • MP-leached DOMs under UV/HP and NaClO treatments exhibited distinct toxicity. [ABSTRACT FROM AUTHOR]

Despite the role of the vadose zone protecting groundwater from contamination, the non-stationarity in this zone makes it difficult to predict the behavior of petroleum hydrocarbons (PH) therein. In laboratory soil columns with sandy and sandy loam soils, we simulated a vadose zone subjected to repeated groundwater-level fluctuation (GLF) to evaluate the behavior of PH under hydrodynamic conditions. The GLF vertically redistributed the PH, the extent of which was pronounced in the sandy soil with a high initial concentration due to the enhanced transport of the immiscible PH through the larger pores. The frequency of GLF did not show a substantial effect on the extent of PH redistribution but largely affected their attenuation. The greater GLF hindered PH volatilization by maintaining a high degree of water saturation, while the subsequent development of a local anaerobic regime inhibited biodegradation, which was more apparent in the sandy loam. Finally, a specific potential risk index was introduced to quantitatively compare the potential risk of PH contamination in different vadose zones exposed to GLF. Overall, the sandy soil contaminated with the higher total PH (TPH) concentration showed markedly higher potential risk indices (i.e., 18.4–29.0%), while the ones comprised of the sandy loam showed 0.6–4.9%, which increased under the greater number of GLF cycles. [Display omitted] • Groundwater-level fluctuation (GLF) affects contaminant behaviors in a vadose zone. • Redistribution of TPHs was not substantially affected by the frequency of GLF. • Frequent GLFs decreased volatilization and biodegradation of TPH therein. • Frequent GLFs increased the groundwater vulnerability to TPH contaminations. • Specific vulnerability varies depending on the soil textures of a vadose zone. [ABSTRACT FROM AUTHOR]

• Potential effect of NO 3 ⁻ on DOC attenuation during ASR was investigated. • NO 3 ⁻ brings a synergetic effect on DIR-induced DOC attenuation. • Fe(II) released from DIR reduces the bioavailability of Fe (hydr)oxides. • Interaction between DIR and NDFO enables Fe (hydr)oxide bioavailability to maintain. Aquifer storage and recovery (ASR) is a promising water management technique in terms of quantity and quality. During ASR, iron (Fe) (hydr)oxides contained in the aquifer play a crucial role as electron acceptors in attenuating dissolved organic carbon (DOC) in recharging water through dissimilatory iron reduction (DIR). Considering the preference of electron acceptors, nitrate (NO 3 ⁻), possibly coexisting with DOC as the prior electron acceptor to Fe (hydr)oxides, might influence DIR by interrupting electron transfer. However, this phenomenon is yet to be clarified. In this study, we systematically investigated the potential effect of NO 3 ⁻ on DOC attenuation during ASR using a series of sediment columns representing typical aquifer conditions. The results suggest that DOC attenuation could be enhanced by the presence of NO 3 ⁻. Specifically, total DOC attenuation was notably higher than that from the stoichiometric calculation simply employing NO 3 ⁻ as the additional electron acceptor to Fe (hydr)oxides, implying a synergetic effect of NO 3 ⁻ in the overall reactions. X-ray photoelectron spectroscopy analyzes revealed that the Fe(II) ions released from DIR transformed the Fe (hydr)oxides into a less bioavailable form, inhibiting further DIR. In the presence of NO 3 ⁻, however, no aqueous Fe(II) was detected, and another form of Fe (hydr)oxide appeared on the sediment surface. This may be attributed to nitrate-dependent Fe(II) oxidation (NDFO), in which Fe(II) is (re)oxidized into Fe (hydr)oxide, which is available for the subsequent DOC attenuation. These mechanisms were supported by the dominance of DIR-relevant bacteria and the growth of NDFO-related bacteria in the presence of NO 3 ⁻. [Display omitted] [ABSTRACT FROM AUTHOR]

• The effective removal of selected TrOCs observed in MAR combined with O 3 and O 3 /H 2 O 2. • MAR showed better performance in reducing CHCl 3 via coupling with O 3 alone. • MAR combined with O 3 and O 3 /H 2 O 2 achieved >50% removal of DOC within the first 5 days. • Pre-oxidation with MAR improved biological stability. A hybrid process of managed aquifer recharge with pre-oxidation was investigated as part of a multiple-barrier approach for safe water production. This study evaluated O 3 and O 3 /H 2 O 2 for the pre-oxidation of urban surface water prior to managed aquifer recharge (MAR) and compared their effectiveness with respect to trace organic contaminants (TrOCs), biostability, and trihalomethane formation potential. The combination of pre-oxidation and MAR was performed using long-term column studies, and the results confirmed the removal of 64 and 56% dissolved organic carbon by using O 3 and O 3 /H 2 O 2 , respectively. MAR combined with O 3 and O 3 /H 2 O 2 achieved >50% removal of dissolved organic carbon with the first 5 days of residence time. O 3 alone showed better performance in alleviating trihalomethane formation potential during chlorination compared to using O 3 /H 2 O 2. The pre-oxidation of urban surface water was effective in attenuating selected TrOCs (35 - >99% removal), and subsequent MAR achieved >99% removal of selected TrOCs within the first 5 days, regardless of pretreatment methods examined in this study. The results of this study provide an understanding of the effects of O 3 and O 3 /H 2 O 2 as pre-oxidation processes on urban surface water prior to MAR, as well as the resulting impact on MAR. [ABSTRACT FROM AUTHOR]

Abstract This study evaluated the performance of a pilot-scale hybrid constructed wetland system for secondary effluent and investigated bulk organic matter characteristics. The hybrid constructed wetland consisted of a vertical-flow (VF) bed followed by a horizontal-flow (HF) bed. We also investigated the effects of hydraulic loading rates and influent organic load on the performance of the pilot-scale VF-HF hybrid constructed wetland. The results showed a high removal efficiency for suspended solids (>95%) and organic matter as determined by total organic carbon (>98.5%) and dissolved organic carbon (>70%), but no significant change in nitrogen removal was observed. The wetland treatment efficiency for suspended solids and organic matter showed a good buffer capacity even when hydraulic loading rates increased from 750 to 1500 L m−2 d−1 and 500–1000 L m−2 d−1 during the VF and HF stages, respectively. Moreover, there was no significant change in the performance when influent organic load increased eight-fold. Fluorescence excitation-emission matrix and liquid chromatography-organic carbon detection (LC-OCD) were used to investigate the dissolved organic matter characteristics in the hybrid VF-HF constructed wetland. Fluorescence excitation-emission matrix spectroscopy showed that both protein- and humic-like substances did not significantly change in the effluent when hydraulic loading rates and organic load increased by two- and eight-fold, respectively. Biopolymers determined using LC-OCD were effectively removed via the VF and HF stage wetlands, indicating the occurrence of biodegradation. Fluorescence excitation-emission matrix spectroscopy and LC-OCD provided the fate of dissolved organic matter characteristics in the hybrid VF-HF constructed wetland. Graphical abstract Image 1 Highlights • A pilot scale hybrid VF-HF constructed wetland was used as tertiary treatment. • VF constructed wetland preferentially removed biodegradable organic matter. • Fluorescence EEM and LC-OCD are helpful to understand DOM characteristics. [ABSTRACT FROM AUTHOR]

Highlights • Sediment batch experiments show mixing-dependent DOC biodegradation rates. • Pore-scale incomplete mixing has significant potential impact on field-scale DOC biodegradation. • Pore-scale incomplete mixing can be a major source of uncertainty over a wide range of Pe and Da numbers. Abstract Biogeochemical reactions take place when reactants are present at the same location and time, which occurs through pore-scale mixing. Although the degree of mixing should be variable in space and time, most conventional reactive transport models do not consider mixing-dependent reaction rates and often make predictions based on rates measured with batch experiments. We quantify the effect of pore-scale mixing on the biodegradation rate of dissolved organic carbon (DOC) with sediment batch experiments, and study its potential impact on the field-scale fate and transport of DOC with numerical simulations. We collected sediment samples from an aquifer storage transfer and recovery (ASTR) field site located in Busan, South Korea, and conducted batch experiments to measure mixing-dependent biodegradation rates. Complete mixing conditions were realized by continuously shaking the batch, and diffusion-limited mixing conditions were realized by keeping the batch under static conditions. The two mixing conditions are most widely used conditions in batch experiments and they also represent the maximum and minimum degree of mixing. The different mixing conditions led to significant differences in the biodegradation rates (a factor of 4.9 on average). We then performed reactive transport modeling using the measured biodegradation rates to study the potential impact of pore-scale incomplete mixing on the field-scale DOC biodegradation. The results show that pore-scale mixing can significantly affect the effectiveness of biodegradation at the ASTR site. We generalize this finding by performing a comprehensive nondimensional sensitivity analysis of the fate and transport of DOC to pore-scale mixing conditions over a wide range of P e ´ clet and Damköhler numbers. We show that pore-scale incomplete mixing can be a major source of uncertainty in field-scale model predictions. [ABSTRACT FROM AUTHOR]

Phosphorous is an essential limiting nutrient for which there is no substitute. Its efficient recovery from sewage treatment plants is important to mitigate both dependence on limited reserves of exploitable phosphate rock and eutrophication of surface waters. Here, we evaluate the use of calcium silicate hydrates (CSH) to recover phosphorous eluted from sewage sludge. Phosphorous elution experiments were conducted with acid and base leaching solutions. The phosphorous recovery efficiency with CSH was compared to that with other calcium compounds, and the final product was analyzed to assess its potential value as fertilizer. Dried sewage sludge from the West Lake Ecological Water Resource Center, South Korea, having 123 g-P kg −1 , was used for these tests. About 55% of the phosphorus in the sludge was released with an elution solution of 0.1 M H 2 SO 4 . A dose of 15 g L −1 of CSH recovered 89.6% of the eluted phosphorous without the need for additional pre-treatment, and the resulting calcium phosphate product (in brushite form, based on XRD analysis) exhibited superior settleability than that resulting from Ca(OH) 2 - and CaCl 2 -induced precipitation. XRD peaks of the calcium sulfate hydrate (in gypsum form) and residual CSH were also observed. The final product contained a relatively high content of the total P 2 O 5 eluted in a 2% citric acid solution (43.1%), which suggests that it might be readily used to fertilize crops. [ABSTRACT FROM AUTHOR]

The contribution by anthropogenic sources to abnormally high Zn concentrations in soils with naturally abundant Zn was investigated at a contaminated site surrounding a Zn smelter in eastern Korea. Nineteen soil samples were collected within a 2 km radius of the smelter, and analyzed for metal concentrations and Pb isotope ratios using an inductively coupled plasma-optical emission spectrometer and -mass spectrometer, respectively. Higher Zn concentrations in locations closer to the smelter implied that the smelter was the source of the Zn pollution. Lead isotope ratios ( 206/207 Pb) from soil samples assumed to be unaffected by the smelter were higher than those found in the contaminated area, suggesting that the raw materials of Zn concentrates (ZnS, sphalerites) and smelting by-products from the smelter with low 206/207 Pb ratios were the anthropogenic Zn source impacting the area. To verify this finding, the mineralogical forms of Zn found in the different soil fractions were investigated by X-ray diffraction analysis, scanning-electron-microscope energy-dispersive spectrometer analysis, and sulfur element analysis. Since approximately 50% of Zn concentrates have particle sizes less than 0.044 mm, the observation of sphalerites and elevated sulfur concentrations in the finer soil fraction (< 0.044 mm) provide substantial support to the hypothesis that the deposition of airborne Zn-containing dust from the smelter is responsible for the high Zn concentration in the area. [ABSTRACT FROM AUTHOR]

The migration of petroleum hydrocarbons in vadose zone involves complex coupled processes such as downward displacement and natural attenuation. Despite its significance in determining groundwater vulnerability to petroleum contamination and optimizing the remedial strategy, it has not been comprehensively studied in terms of overall processes under field-relevant conditions. In this study, a series of unsaturated soil column experiments were conducted by simulating subsurface diesel contamination within a vadose zone using different soil textures at different soil bulk densities and initial diesel concentrations, while partly exposing them to simulated precipitation. The results showed that the soil column with less fine fraction was favorable for the downward migration of diesel but unfavorable for its natural degradation. However, precipitation complicated the relative conductivities of multiple fluids (water, air, and diesel) through the pore network, therby decreasing diesel migration and degradation. For example, the downward migration of diesel in the SL column decreased by 8.4% under precipitation, while the overall attenuation rate dropped to almost 0.24% of its original state. Lowering bulk density (from 1.5 to 1.23 g/cm3), however, could enhance the attenuation rate presumably due to the secured void space for the incoming fluids. A high initial concentration of diesel (2%; w/w) inhibited its natural attenuation, while its influence on its vertical propagation after the precipitation was not significant. The present findings provide a mechanistic basis for approximating the behavior of petroleum hydrocarbons in a random vadose zone. [Display omitted] • Fate and transport of diesel in vadose zone was investigated in a holistic manner. • Soil pore network governs both the migration and natural attenuation of diesel. • Precipitation can enhance or inhibit the diesel behavior depending on soil textures. • Low soil density can reudce the decrease of diesel attenuation under precipitation. • High initial concentration of diesel can decrease its natural attenuation. [ABSTRACT FROM AUTHOR]

We investigate tracer transport on random discrete fracture networks that are characterized by the statistics of the fracture geometry and hydraulic conductivity. While it is well known that tracer transport through fractured media can be anomalous and particle injection modes can have major impact on dispersion, the incorporation of injection modes into effective transport modeling has remained an open issue. The fundamental reason behind this challenge is that—even if the Eulerian fluid velocity is steady—the Lagrangian velocity distribution experienced by tracer particles evolves with time from its initial distribution, which is dictated by the injection mode, to a stationary velocity distribution. We quantify this evolution by a Markov model for particle velocities that are equidistantly sampled along trajectories. This stochastic approach allows for the systematic incorporation of the initial velocity distribution and quantifies the interplay between velocity distribution and spatial and temporal correlation. The proposed spatial Markov model is characterized by the initial velocity distribution, which is determined by the particle injection mode, the stationary Lagrangian velocity distribution, which is derived from the Eulerian velocity distribution, and the spatial velocity correlation length, which is related to the characteristic fracture length. This effective model leads to a time-domain random walk for the evolution of particle positions and velocities, whose joint distribution follows a Boltzmann equation. Finally, we demonstrate that the proposed model can successfully predict anomalous transport through discrete fracture networks with different levels of heterogeneity and arbitrary tracer injection modes. [ABSTRACT FROM AUTHOR]

Inspired by the mechanism behind self-sensitized destruction of dyes on semiconductor photocatalysts, we herein present the first instance of visible-light-induced activation of periodate (IO 4 − ) into reactive iodine radicals via sensitized electron transfer from an organic dye, Rhodamine B (RhB). The IO 4 − reduction not only leads to oxidative decolorization of RhB but also formation of reactive intermediates that degrade organic compounds. Electron transfer from the excited dye to IO 4 − was confirmed by detecting RhB radical cation (RhB + ) and measuring its lifetime. The efficiency of organic compound degradation was found to significantly vary depending on the target substrate, i.e., phenol, bisphenol A, and 4-chlorophenol were rapidly decomposed, whereas benzoic acid, carbamazepine, 4-nitrophenol, and sulfamethoxazole exhibited moderate decomposition rate. Lines of evidence in addition to the substrate specificity, such as insignificant hydroxylation, non-stoichiometric dechlorination, and marginal quenching effects of organic/inorganic compounds (e.g., methanol, natural organic matters, and chloride ion), points toward the involvement of iodate radical (IO 3 ). The dye-sensitized IO 4 − activation process was also found to be highly effective in inactivation of MS2 bacteriophage. [ABSTRACT FROM AUTHOR]

The nonstationary nature of water and oxygen content in the vadose zone determines various biogeochemical reactions regarding arsenic (As) therein, which affects the groundwater vulnerability to As contamination at a site. In the present study, we evaluated the effect of soil organic matter (OM) on the behavior of As using specifically designed soil columns that simulated the vadose zone. Three wet-dry cycles were applied to each of the four columns with different OM contents and bulk densities. OM was found to exhibit variable effects, either inhibiting or accelerating the mobilization of As, depending on bulk density. At a moderate bulk density (< 1.27 g/cm3), OM slightly lowered the pH of pore water, which enhanced the sorption of As onto the iron (Fe) oxides, promoting the retention of As in soil. In the soil column with a relatively higher bulk density (1.36 g/cm3), however, the dissimilatory reduction of iron oxides was triggered by rich OM under oxygen-limited conditions. X-ray absorption spectroscopy analysis revealed that alternate wetting and drying transformed the Fe oxides in the soil by reductive dissolution and subsequent re-precipitation. Consequently, As was not stably retained in the soil, and its mobilization downwards was further accelerated. [Display omitted] • Soil organic matter(OM) affects the groundwater vulnerability to As contamination. • Under moderate soil density, OM enhances the As retention in a vadose zone. • Under high soil density, OM accelerates the As mobilization through a vadose zone. • Redox dynamics from nonstationarity altered mineral composition in soil water. [ABSTRACT FROM AUTHOR]

Despite its environmental significance, little is known about denitrification in vadose zones owing to the complexity of such environments. Here, we investigated denitrification in unsaturated soils with different pore distributions. To this end, we performed batch-type denitrification experiments and analyzed microbial community shifts before and after possible reactions with nitrates to clarify the relevant denitrifying mechanism in the microcosms. For quantitative comparison, pore distribution in the test soil samples was characterized based on the uniformity coefficient (C u) and water saturation degree (SD). Micro-CT analysis of the soil pore distribution confirmed that the proportion of bigger-sized pores increased with decreasing C u. However, oxygen diffusion into the system was controlled by SD rather than C u. Within a certain SD range (51–67%), the pore condition changed abruptly from an oxic to an anoxic state. Consequently, denitrification occurred even under unsaturated soil conditions when the SD increased beyond 51–67%. High throughput sequencing revealed that the same microbial species were potentially responsible for denitrification under both partially (SD 67%), and fully saturated (SD of 100%) conditions, implying that the mechanism of denitrification in a vadose zone, if it exists, might be possibly similar under varying conditions. [Display omitted] • Denitrifications in unsaturated soils with different pore networks were examined. • Saturation degree (SD) of soils takes priority over the pore size in denitrification. • Denitrification occurs even under unsaturated soil conditions. • The same microbes might work for denitrification in a vadose zone if it occurs. [ABSTRACT FROM AUTHOR]

The fate and transport of microplastics (MPs) during deep bed filtration were investigated using combined laboratory experiments and numerical modeling. A series of column experiments were conducted within the designated ranges of six operating parameters (i.e., size of the MP and collector, seepage velocity, porosity, temperature, and ionic strength). A variance-based sensitivity analysis, the Fourier amplitude sensitivity test, was conducted to determine the priority in affecting both the attachment coefficient at the pore scale, and the subsequent stabilized height of the breakthrough curve at the continuum scale, which follows non-monotonic trends with singularity in the size of MP (i.e., 1 µm). Finally, Damkohler numbers were introduced to analyze the dominant mechanisms (e.g., attachment, detachment, or straining) in the coupled hydro-chemical process. The robustness of conceptual frameworks bridges the gap between pore-scale interactions and the explicit MPs removal in the continuum scale, which could support decision-making in determining the priority of parameters to retain MPs during deep bed filtration. [Display omitted] • Both experimental and numerical models were established for deep bed filtration. • The priority of factors affecting k att and the subsequent BTCs were quantified. • Damkohler numbers were introduced to estimate the dominant mechanisms. • The method can be used as a design and operational criteria for sand filtration. [ABSTRACT FROM AUTHOR]

[Display omitted] • The nanoscale coating layer is successfully formed using PDA modification. • A synchronous lithiation strategy is used to the surface modification. • The Li 6.25 La 3 Zr 2 Al 0.25 O 12 coating improves the LiNi 0.88 Co 0.05 Mn 0.07 O 2 performance. • The fast ionic conductor coating layer facilitate Li-ion migration. • The protective layer effectively suppresses side reactions during long-term cycling. Ni-rich cathode materials have promising applications in lithium-ion batteries owing to their high energy density and reasonable cost. The surface stabilization of these materials is vital for achieving excellent electrochemical performance. In this study, a fast ionic conductor, Li 6.25 La 3 Zr 2 Al 0.25 O 12 (LLZAO), was successfully coated on the surface of LiNi 0.88 Co 0.05 Mn 0.07 O 2 (LNCM) using a polydopamine (PDA) modification method. The abundant catechol groups of the intermediate PDA layer on the Ni 0.88 Co 0.05 Mn 0.07 (OH) 2 (NCM(OH) 2) precursor attracted metal ions in an aqueous solution, and a uniform LLZAO coating layer was formed after calcination under an O 2 flow. The presence of the LLZAO protective film on the surface of LNCM was confirmed using several characterization techniques. The LLZAO-coated LNCM exhibited superior electrochemical properties compared to those of the pristine LNCM. Moreover, the LLZAO-coated LNCM demonstrated excellent electrochemical stability even at a high temperature (60 ℃). The deterioration of the surface structure of LNCM was significantly suppressed by the formation of the LLZAO coating layer, and LLZAO improved the Li+ ion transport at the electrode/electrolyte interface. [ABSTRACT FROM AUTHOR]

The potential risks of nanoparticles (NPs) in sunscreens being released into swimming water were evaluated by a series of laboratory experiments simulating the fate and transport of NPs in outdoor swimming pools. NPs released from sunscreen-applied skin were estimated using pig skins covered with five different commercial sunscreens containing TiO 2 , ZnO, or both at various concentrations. Assuming that the swimming water treatment processes consisted of filtration, UV irradiation, heating, and chlorination, possible removal of the released NPs by each process was estimated. Generation of hydrogen peroxide (H 2 O 2 ) by the NPs under sunlight and after UV photochemical treatment were measured, and the H 2 O 2 concentration possibly present in the swimming pool was calculated based on some specific scenarios of operating an outdoor swimming pool. It was found that a significant amount of the NPs in sunscreens could be released into the swimming water, and accumulate during circulation through the treatment system. However, the concentration of H 2 O 2 possibly present in the swimming pool should be below the level at which an adverse effect to bathers is concerned. [ABSTRACT FROM AUTHOR]

In this study, indigenous microbes enabling Fe reduction under saline groundwater conditions were identified, and their potential contribution to Fe release from aquifer sediments during managed aquifer recharge (MAR) was evaluated. Sediment and groundwater samples were collected from a MAR feasibility test site in Korea, where adjacent river water will be injected into the confined aquifer. The residual groundwater had a high salinity over 26.0 psu, as well as strong reducing conditions (dissolved oxygen, DO < 2.0 mg/L; oxidation-reduction potential, ORP < − 100 mV) with high Fe 2 + concentrations. The indigenous microbes that mediate the reduction of Fe-minerals in this deep saline aquifer were found to be Citrobacter sp. However, column experiments to simulate field operation scenarios indicated that additional Fe release would be limited during MAR, as the dominant microbial community in the sediment would shift from Citrobacter sp. to Pseudomonas sp. and Limnohabitans sp. as river water injection alters the pore water chemistry. [ABSTRACT FROM AUTHOR]

Aquifer storage and recovery (ASR) is an important water resources management technique that involves the injection of a large volume of water underground. For the successful implementation of an ASR project, a target aquifer should have a sufficient injection capacity, which is the maximum volume of water that can be safely injected. In nature, no aquitard is perfectly impermeable, and inter-aquifer leakage may have a major impact on injection capacity. Despite the importance of determining the injection capacity for ASR planning, there is no quantitative methodology that estimates the injection capacity of leaky aquifers. In this study, we first develop a solution for injection capacity with inter-aquifer leakage based on the Hantush - Jacob solution, and conduct a comprehensive sensitivity analysis to elucidate the influence of inter-aquifer leakage on injection capacity. From the sensitivity analysis, we show that inter-aquifer leakage can impact injection capacity by more than one order of magnitude, depending on the hydrogeological and operational parameters. We then develop a practical mapping methodology that estimates the injection capacity of leaky aquifers. We demonstrate the proposed methodology by applying it to a potential ASR site in Minnesota, USA, where ASR is considered as a solution to alleviate groundwater contamination by PFAS chemicals. The case study results reveal significant spatial variability in injection capacity over the study area and show an average increase in the injection capacity of about 26% compared to that in the nonleaky scenario. We also analyze the uncertainty in the estimated injection capacity due to the variability of aquitard properties and show that the variability of aquitard vertical hydraulic conductivity leads to a larger uncertainty in the estimated injection capacity than does the variability of aquitard thickness. This study elucidates the effects of inter-aquifer leakage on injection capacity and provides a practical methodology for injection capacity mapping. • Influence of inter-aquifer leakage on well-injection capacity is investigated. • Solution for injection capacity with inter-aquifer leakage is developed. • Sensitivity analysis elucidates the aquifer leakage effects on injection capacity. • Practical aquifer-scale injection capacity mapping methodology is developed. • The mapping methodology is successfully applied to a potential ASR site. [ABSTRACT FROM AUTHOR]

Assessment of Zn toxicity/mobility based on its speciation and transformations in soils is critical for maintaining human and ecosystem health. Zn-concentrate (56 % Zn as ZnS, sphalerite) has been imported through a seaport and transported to a Zn-smelter for several decades, and smelting processes resulted in aerial deposition of Zn and sulfuric acids in two geochemically distinct territories around the smelter (mountain-slope and riverside). XAFS analysis showed that the mountain-slope soils contained franklinite (ZnFe 2 O 4) and amorphous (e.g., sorbed) species of Zn(II), whereas the riverside sediments contained predominantly hydrozincite [Zn 5 (OH) 6 (CO 3) 2 ], sphalerite, and franklinite. The mountain-slope soils had low pH and moderate levels of total Zn (~ 1514 ppm), whereas the riverside sediments had neutral pH and higher total Zn (12,363 ppm). The absence of sphalerite and the predominance of franklinite in the mountain-slope soils are attributed to the susceptibility of sphalerite and the resistance of franklinite to dissolution at acidic pH. These results are compared to previous Zn analyses along the transportation routes, which showed that Zn-concentrate spilled along the roadside in dust and soils underwent transformation to various O-coordinated Zn species. Overall, Zn-concentrate dispersed in soils and sediments during transportation and smelting transforms into Zn phases of diverse stability and bioavailability during long-term weathering. [Display omitted] • ZnS and smelting products released in soils transformed into diverse Zn species. • Low pH mountain soils near smelter contained franklinite and amorphous Zn(II). • Neutral pH riverside soils contained high Zn as hydrozincite, sphalerite, franklinite. • The diverse speciation necessitates multiple pathway description of Zn transport. [ABSTRACT FROM AUTHOR]

The natural attenuation potential of a vadose zone against diesel is critical for optimizing remedial actions and determining groundwater vulnerability to contamination. Here, diesel attenuation in unsaturated soils was systematically examined to develop a qualitative relationship between physical soil properties and the natural attenuation capacity of a vadose zone against diesel. The uniformity coefficient (C u) and water saturation (S w , %) were considered as the proxies reflecting the degree of effects by porous network and water content in different soils, respectively. These, in turn, are related to the primary diesel attenuation mechanisms of volatilization and biodegradation. The volatilization of diesel was inversely proportional to C u and S w , which could be attributed to effective pore channels facilitating gas transport. Conversely, biodegradation was highly proportional to C u under unsaturated conditions (S w = 35–71%), owing to nutrients typically associated with fine soil particles. The microbial community in unsaturated soils was affected by S w rather than C u. The overall diesel attenuation including volatilization and biodegradation was optimized at S w = 35% for all tested soils. [Display omitted] • Natural attenuation of diesel was investigated in unsaturated soils. • The uniformity coefficient (C u) and water saturation (S w) were primary variables. • Diesel volatilization was inversely proportional to C u and S w in the local range. • Diesel biodegradation was highly proportional to C u under unsaturated conditions. • Microbial community was primarily changed by S w rather than C u. [ABSTRACT FROM AUTHOR]

A new material was developed and evaluated for the targeted removal of trichlorophenol (TCP) from among potential interferents which are known to degrade removal activity. To achieve TCP-targeted activity, an alginate bead containing nanoscale palladium/zero-valent iron (Pd/nZVI) was coated with a highly hydrophobic oleic acid layer. The new material (Pd/nZVI-A-O) preferentially sorbed TCP from a mixture of chlorinated phenols into the oleic acid cover layer and subsequently dechlorinated it to phenol. The removal efficacy of TCP by Pd/nZVI-A-O was not affected by co-existing organic substances such as Suwannee River humic acid (SRHA), whereas the material without the oleic acid layer (Pd/nZVI-A) became less effective with increasing SRHA concentration. The inorganic substances nitrate and phosphate significantly reduced the reactivity of Pd/nZVI-A, however, Pd/nZVI-A-O showed similar TCP removal efficacies regardless of the initial inorganic ion concentrations. The influence of bicarbonate on the TCP removal efficacies of both Pd/nZVI-A and Pd/nZVI-A-O was not significant. The findings from this study suggest that Pd/nZVI-A-O, with its targeted, constant reactivity for TCP, would be effective for treating this contaminant in surface water or groundwater containing various competitive substrates. [ABSTRACT FROM AUTHOR]

This study evaluates the capacity of various inorganic oxidants (IO 4 − , HSO 5 − , S 2 O 8 2− , H 2 O 2 , and BrO 3 − ) to act as alternative electron acceptors for WO 3 -mediated photocatalytic oxidation. Combination with IO 4 − drastically increased the rate of photocatalytic degradation of 4-chlorophenol by WO 3 , while the other oxyanions only negligibly improved the photocatalytic activity. The extent of the photocatalytic performance enhancement in the presence of inorganic oxidants correlated well with the efficiencies for: (1) hydroxylation of benzoic acid as an OH probe, (2) dechlorination of dichloroaceate as a hole scavenger, and (3) water oxidation with O 2 evolution. The results suggest that the promoted charge separation primarily causes kinetic enhancement in photocatalytic degradation using the WO 3 /IO 4 − system. In marked contrast to the substrate-dependent activity of the photochemically activated IO 4 − (generating selective IO 3 ), the efficiency of the WO 3 /IO 4 − system for photocatalytic degradation did not sensitively depend on the type of target organic compound, which implies the existence of a minor contribution of the photocatalytic reduction pathway associated with the production of IO 3 as a secondary oxidant. On the other hand, the insignificant inhibitory effect of methanol as an OH quencher may reveal the possible involvement of SO 4 − in the improved photocatalytic activity of the WO 3 /HSO 5 − system. The alternative use of platinized WO 3 , where the interfacial electron transfer occurs in a concerted step, achieved a highly accelerated photocatalytic oxidation in the presence of HSO 5 − and polyoxometalates as electron scavengers. In particular, the surface loading of nanoscale platinum appeared to retard the reaction route for SO 4 − generation associated with a one-electron transfer. [ABSTRACT FROM AUTHOR]

With the continuous improvement in genotyping and molecular phenotyping technology and the decreasing typing cost, it is expected that in a few years, more and more clinical studies of complex diseases will recruit thousands of individuals for pan-omic genetic association analyses. Hence, there is a great need for algorithms and software tools that could scale up to the whole omic level, integrate different omic data, leverage rich structure information, and be easily accessible to non-technical users. We present GenAMap, an interactive analytics software platform that 1) automates the execution of principled machine learning methods that detect genome- and phenome-wide associations among genotypes, gene expression data, and clinical or other macroscopic traits, and 2) provides new visualization tools specifically designed to aid in the exploration of association mapping results. Algorithmically, GenAMap is based on a new paradigm for GWAS and PheWAS analysis, termed structured association mapping, which leverages various structures in the omic data. We demonstrate the function of GenAMap via a case study of the Brem and Kruglyak yeast dataset, and then apply it on a comprehensive eQTL analysis of the NIH heterogeneous stock mice dataset and report some interesting findings. GenAMap is available from http://sailing.cs.cmu.edu/genamap. [ABSTRACT FROM AUTHOR]