Treatment Scenarios Research Articles

Response of four Vallisneria taxa to aquatic herbicides

Abstract Native aquatic macrophytes such as Vallisneria americana Michx. are often desirable in aquatic ecosystems due to the ecological benefits they provide but are threatened by competition from invasive taxa including nonnative Vallisneria taxa and hydrilla (Hydrilla verticillata L.f. Royle). Identifying potential selective herbicide management options can provide options to minimize impacts to native taxa in restoration and aquatic invasive plant management programs. Greenhouse mesocosm experiments were conducted in 2023 to investigate herbicide efficacy on two native eelgrass species (V. americana and V. neotropicalis Vict.), two nonnative taxa (V. australis S.W.L. Jacobs & Les and V. spiralis × V. denseserrulata Makino) and H. verticillata. Herbicide applications included endothall, diquat, florpyrauxifen-benzyl, fluridone, and flumioxazin and select combinations of these herbicides used in H. verticillata management. Endothall alone provided 90 to 100% aboveground biomass reduction at 3000 µg L-1 with at least 24 hours of continuous or intermittent exposure to all native and invasive species at six weeks after exposure, whereas florpyrauxifen-benzyl applied alone resulted in minimal aboveground biomass reduction. A 45 day of exposure of fluridone (10 µg L-1) resulted in 95% biomass reduction on V. americana and 7 to 48% other tested taxa. The combination of flumioxazin and florpyrauxifen-benzyl resulted in 90 to 100% aboveground biomass reduction and endothall combined with florpyrauxifen-benzyl resulted in 93 to 100% aboveground biomass reduction across taxa. Reductions in belowground biomass mirrored trends observed in aboveground biomass. No treatments selectively controlled invasive Vallisneria without injury to native Vallisneria, although efficacy was observed on hydrilla. These insights provide an understanding for differences between these Vallisneria for researchers moving forward with selectively targeting H. verticillata in the presence of native Vallisneria species and two new aquatic invasive plants. Future research should expand treatment scenarios, increase the study period, and identify potential integrated plant management strategies for field scenarios.

Development of an automated process for monitoring of amiodarone treatment

Abstract Background Amiodarone treatment requires repeated laboratory evaluations of thyroid and liver function due to risk of side effects during long-term administration. Robotic process automation (RPA) represents the use of software robots to automate repetitive and routine tasks typically performed by humans. Purpose We aimed to develop an RPA using a diagnostic classification algorithm and clinical support system for follow-up of amiodarone treatment. Methods Based on international guidelines and clinical specialist advisory we constructed an RPA which was studied in a test environment in parallel with routine amiodarone treatment. Expert advice was integrated through a series of collaborative workshops, ensuring alignment of the algorithm with current best practices in thyroid and liver disease management. The RPA provided recommendations on the time interval to next laboratory testing and suggestions for patient management to the physician, who was serving as a human-in-the-loop responsible for clinical decisions. Results After iterative improvements the RPA was evaluated against physician orders (n=390 paired orders) without technical failures. The recommended time interval to next follow-up was (mean ± SD) 4.5 ± 2.4 vs. 3.1 ± 1.4 months for RPA vs. physician (p<0.0001). While normal laboratory findings resulted in recommended follow-up in 6 months by the RPA (72.2%) this was only ordered in 9.9% by the physician (Figure). Physicians’ orders clustered between 3-4 months (58.5%). All patients diagnosed with new side effects (n=12) were detected and communicated correctly by the RPA, whereas only 8 were correctly detected and responded to by the physician (Table). Conclusions An automated process constitutes a reliable alternative to the current fully manual management of amiodarone follow-up. It may reduce manual labour, frequency of laboratory testing and detect side effects with increased precision, thereby reducing costs and enhancing patient value. While the RPA shows promise, further research is needed to explore its adaptability to other treatment scenarios.

How different soil surface treatments in urban areas affect soil pore structure and associated soil properties and processes

Soil water and temperature regimes in urban environments are greatly affected by different surface treatments, and these may lead even to changes in soil properties. The goal of this study was to find out how soil properties had changed after 8 years of soil surface modification. Five surface treatment scenarios were considered: bare soil (BS), bark chips (BC), concrete paving (CP), mown grass (MG), and unmown grass (UG). X-ray computed tomography and micromorphological analyses showed that character of pores in soils with grass (MG, UG), which were mainly influenced by organisms living in soils and roots, differed from pore character in soil covers BC or CP, which mostly were impacted by organisms living in soils. Both groups differed from BS, which was predominantly affected by the regular treatment consisting in weed removal and soil loosening. Soil under BC was more compact than for other treatments due to decomposition of the bark chips mulch and migration of mulch components. Organic matter content was greatest but its quality lowest in the BC soil, followed by UG, MG, CP, and BS. The highest aggregate stability assessed using the water-stable aggregates (WSA) index was found for UG, followed by MG, BC, CP, and BS. The greatest water retention ability was observed for BC followed by UG, MG, CP, and BS. The unsaturated hydraulic conductivities for pressure head of –2 cm measured for UG, MG, and BS were much higher than were those for CP and BC. Finally, the greatest net CO2 efflux was measured for BC and MG, followed by UG, CP, and BS. CO2 emission correlated negatively with soil physical quality expressed as slope of the soil water retention curve at its inflection point. In general, the best soil conditions were observed for UG. No treatment considerably aggravated soil condition.

Treatment preferences in spinal muscular atrophy: A swing weighting study for caregivers of patients with SMA types 1 and 2.

Spinal muscular atrophy (SMA) is a genetic neuromuscular disorder characterized by skeletal muscle weakness and atrophy. Patients with SMA types 1 and 2 develop severe disabilities conferring substantial patient and caregiver burden. Caregiver treatment characteristic preferences are useful for informing treatment choices and improving adherence. We aimed to identify drivers of SMA treatment preference from the perspective of caregivers of patients with SMA types 1 or 2 in the United States. We quantified the relative importance of different treatment characteristics and compared preferences for hypothetical treatment scenarios. Treatment attributes and attribute levels elicited were based on a literature search and interviews with caregivers and health care professionals. The most important treatment characteristics from the perspective of health care professionals and caregivers were identified and used in a survey to quantify relative importance for caregivers. Caregivers completed surveys regarding their preferences using swing weighting methodology. These results were used to estimate the relative value of four hypothetical SMA treatment scenarios exploring different modes of treatment administration. The swing weighting survey, completed by 20 caregivers, demonstrated that the attributes driving treatment preference were reduction in permanent ventilation needs and risk of severe adverse events, followed by treatment access (including cost coverage and availability), increased ability to sit without support, and less treatment administration burden. The hypothetical SMA treatment scenarios with the highest relative value offered an easier mode of administration, lowest risk of severe adverse events, less need of permanent ventilation, and highest ability of patients to feed and sit without support. Our findings suggest that caregivers prefer a treatment with reduced clinical burden and risk in which the cost is covered and treatment is available in the short term. These results can provide important contextual information for decision-makers and help promote patient-centered care for patients with SMA.

Margin derivation from intrafraction patient motion of multi-target, single isocentre, brain stereotactic radiosurgery treatments.

Brain metastases are the most common intracranial malignancy and remain a substantial source of morbidity and mortality in cancer patients. Linear accelerator based stereotactic radiosurgery (SRS) is widely used and is frequently delivered by hypo-fractionnated volumetric modulated arc therapy using non-coplanar beams, where geometric accuracy and planning margins are a majorconcern. To give a practical analysis of intrafraction patient motion for multi-target, single isocentre, brain SRS treatments and to derive adapted GTV-to-PTV margins. Data of 154 lesions, spread over 85 fractions from 56 patients treated in our institution with the Varian HyperArc SRS solution was processed. Intrafraction patient motion were recorded using an Optical Surface Monitoring System during irradiation. The present study focuses on small tumor volumes, roughly equal or inferior to 1.5 , and frameless mask-based immobilization. For each treatment session, a tumor displacement vector matrix was calculated from the patient drifts as a function of time. Data were combined together into a representative treatment scenario and the dosimetric impact of GTV displacement was calculated. Recommended margins due to patient motion range between 0.3 and 1mm, depending on the distance tumor-isocentre, and the desired GTV edge dose coverage. Those values should be added quadratically with other sources of uncertainty, such as mechanical isocentre and kV-MVmisalignment. Thorough analysis of intrafraction patient motion was performed, the dosimetric impact was calculated for different scenarios, and adequate GTV-to-PTV margins were derived. These values vary according to the distance isocentre-to-GTV, as well as the desired dose coverage, and should be chosenadequately.

Sublethal Effects of α-Cypermethrin on the Behavioral Asymmetries and Mating Success of Alphitobius diaperinus.

Sublethal exposure to insecticides can adversely impact various biological and behavioral characteristics of insects. Although α-cypermethrin has been previously tested for its effects on control of Alphitobius diaperinus, there is no knowledge about the effect of this insecticide on its behavioral asymmetries and mating success. Μales at all exposures (control, LC10, and LC30), that first approached their mate, showed right-biased tendency (approached their mate from their right side) in mate recognition. Females, however, showed variation in this behavior between the three exposures. Right-biased tendency of males in all treatment scenarios led to a higher percentage of successful copulations compared to the three other directions. For males that first approached their mate, the insecticide did not affect their lateralization of the first approach but did affect their copulation success. The duration of copulation time was reduced after the exposure to the insecticide, with the longest duration noted in the control females (63.0 s) and the lowest in the α-cypermethrin LC30 females (46.9 s). Moreover, at the α-cypermethrin LC10 exposure, mate recognition time was reduced, as opposed to α-cypermethrin LC30 exposure where mate recognition time was increased. These results can be further utilized to uncover the behavioral impacts of insecticides, enhancing the effectiveness of pest management in warehouses and poultry production facilities.

Predicting chemotherapy-induced thrombotoxicity by NARX neural networks and transfer learning

BackgroundThrombocytopenia is a common side effect of cytotoxic chemotherapies, which is often dose-limiting. Predicting an individual’s risk is of high clinical importance, as otherwise, a small subgroup of patients limits dosages for the overall population for safety reasons.MethodsWe aim to predict individual platelet dynamics using non-linear auto-regressive networks with exogenous inputs (NARX). We consider different architectures of the NARX networks, namely feed-forward networks (FNN) and gated recurrent units (GRU). To cope with the relative sparsity of individual patient data, we employ transfer learning (TL) approaches based on a semi-mechanistic model of hematotoxicity. We use a large data set of patients with high-grade non-Hodgkin’s lymphoma to learn the respective models on an individual scale and to compare prediction performances with that of the semi-mechanistic model.ResultsOf the examined network models, the NARX with GRU architecture performs best. In comparison to the semi-mechanistic model, the network model can result in a substantial improvement of prediction accuracy for patients with irregular dynamics, given well-spaced measurements. TL improves individual prediction performances.ConclusionNARX networks can be utilized to predict an individual’s thrombotoxic response to cytotoxic chemotherapy treatment. For reasonable model learning, we recommend at least three well-spaced measurements per cycle: at baseline, during the nadir phase and during the recovery phase. We aim at generalizing our approach to other treatment scenarios and blood lineages in the future.

Optimization of water and nitrogen management in wheat cultivation affected by biochar application − Insights into resource utilization and economic benefits

In the context of global climate change and natural resource scarcity, agricultural production is facing multiple challenges in improving crop yields and optimizing natural resource use. It is of great practical significance to optimize agricultural practices to achieve sustainable agricultural development. In this study, a two-year winter wheat field experiment was conducted in the Guanzhong Plain, Shaanxi, China, from 2020 to 2022 to assess the effects of biochar, irrigation, and N fertilizer rates on the yield, water-nitrogen use efficiency, and economic benefits of winter wheat. Specifically, biochar was applied to winter wheat at 30 t ha−1 in combination with two irrigation application rates, including regular irrigation (I100; actual evapotranspiration) and deficit irrigation (I80; 0.8 actual evapotranspiration), and three different N fertilizer rates at 210 (NH; conventional applied N rate by local farmers), 160 (NM; moderate N rate), and 110 kg ha−1 (NL; low N rate). The control groups in this study consisted of experimental plots under the NM and N0 (no N) without biochar application. The aboveground dry matter mass (ADM), yield, and net ecosystem economic budget (NEEB) of winter wheat showed increasing trends with increasing N application rates without significant differences between the NH and NM treatments. On the other hand, the water use efficiency (WUE), agronomic N fertilizer use efficiency (aNUE), and N fertilizer recovery efficiency (NRE) showed increasing-decreasing trends with increasing N fertilizer rates, reaching the highest values under the NM treatment scenario. The biochar addition significantly increased the winter wheat yield and WUE (P<0.05). On the other hand, the I80 treatment resulted in higher WUE and irrigation water use efficiency (IWUE) than those under I100 by 5.63 and 13.52 %, respectively. TOPSIS results indicated that the combined I80B1NM treatment was the optimal winter wheat management practice, maintaining high productivity while improving resource use efficiency and economic benefits. The results of the present study provide an important scientific basis and guidance for ensuring efficient and high-quality agricultural products in the Guanzhong Plain and other regions in China with similar climatic characteristics.

Adolescents' evaluations of peer and teacher unfair treatment in science, technology, engineering, and mathematics classes: Expected interventions.

This study explores adolescents' evaluations of unfair teacher and peer behavior in science, technology, engineering, and mathematics (STEM) classes. Participants included ninth and tenth grade students from five public schools in the Southeastern United States, (N = 577, 45.9% female, 49% male, 5% other/prefer not to say/unsure). Students were ethnically representative of their communities: 48% White/European American, 22.7% Black/African American, 14% Latino/a/e/x, and 15.3% multi-racial/other/prefer not to say. Measures assessed adolescents' responses to hypothetical scenarios of unfair treatment. The findings indicate that adolescents recognize both teacher and peer unfair behavior as wrong, with nuanced differences based on participants' gender and grade. Attribution analysis reveals varied expected reasons for unfair treatment. Responses to unfair behavior differ, with adolescents more likely to confront peers than teachers. Demographic factors, school climate, discrimination, belonging, and critical consciousness contribute to variations in judgments and responses. The study highlights the importance of addressing unfair treatment in STEM settings to foster inclusivity and support student persistence in STEM.

Performance comparison of modified polyethersulfone membrane with graphene oxide and molybdenum disulfide for effective filtration of urban surface water

In the current water treatment scenario, membrane filtration is a crucial technology due to its ability to effectively remove pollutants, ensuring clean and safe water. However, a significant challenge to its widespread application is membrane fouling, which reduces membrane efficiency and service life. Various membrane modifications have been studied to enhance fouling resistance. In this work, the effect of adding graphene oxide (GO) and molybdenum disulfide (MoS2) nanoparticles for the fabrication of mixed polyethersulfone (PES) membranes was evaluated. The modified membranes were evaluated for pollutant removal efficiency and fouling resistance using model humic acid solutions and surface water samples. The PES-GO membranes demonstrated significantly improved hydrophilicity, up to 43% reduction in protein deposition, and an average flux recovery ratio (FRR) of 63%, superior to the control PES membrane, resulting in reduced fouling and sustained high permeability. Nevertheless, although PES-MoS2 exhibited high rejection rates of dissolved organic matter and UV254, they also showed higher foulant adsorption and lower FRR, likely due to the development of a colloidal fouling when treating more complex water matrices. Attenuated Total Reflectance Fourier-Transform Infrared (ATR-FTIR) analysis confirmed the deposition of organic foulants, with polysaccharides and proteins identified as major contributors to fouling. These findings suggest that while GO-enhanced PES membranes offer improved water treatment performance, modifications with MoS2 require careful consideration of feedwater composition. Future work should focus on optimizing nanoparticle integration and evaluating membrane effectiveness for diverse water sources.

Enhancing the machinability and formability of tool steels through spheroidizing annealing heat treatment

This research focuses on enhancing the machinability and formability of tool steels by applying different heat treatment scenarios. Machinability is the process of cutting metals with the least energy effort, while formability is the ability of a metal to be shaped into different forms without severe damage. Enhancing machinability and formability improves dimensional tolerance and surface finish and increases the lifetime and reliability of tool steels. This research will use two tool steel materials, “D2” and “O1,” which are widely used in industry. They contain high percentages of carbon by weight (1.55% and 0.95%, respectively). The “O1” tool steel is used in blanking dies and room-temperature cutting tools, whereas the “D2” tool steel is used for carpentry cutting tools and gauges. The different heat treatment scenarios are based on the latest literature, which shows excellent results with other materials. The heat treatment plan is set to cover various scenarios to determine the most effective treatment for machinability and formability. The experimental work will include several mechanical tests: tensile tests, compression tests, hardness tests, and toughness tests. The conclusions regarding the different heat treatments will be based on the test results.

Forest management with fire simulation

In this work, we address a forest management problem for timber production with fire concerns, employing a novel simulation-based optimization approach wherein forest management is iteratively guided by the feedback from fire spread simulations.The forest management problem involves selecting an alternative prescription for each stand, subject to various restrictions (e.g. bounds on ecosystems services), to maximize the net present value. For each stand, prescriptions involve projecting forest conditions and outcomes using species-specific growth and yield models, combined with different fuel treatment scenarios. In each iteration, the optimization problem is solved. Fire travel times between adjacent points in a grid representing the forest are calculated, based on fuel models associated with the selected prescriptions and other conditions as wind and slopes. Fire spread is simulated for all potential ignitions. Fire paths with a rate of spread greater than a given threshold are identified and constraints are added to the forestry problem to exclude their associated prescriptions to be jointly selected. This problem is re-optimized and the process is repeated until there are no such paths.We describe computational experiments in a Portuguese forest showing how trade-offs between the net present value and the maximum fire rate of spread can be obtained. When too restrictive conditions are imposed on fire, the approach suggests a set of stands to become fire breaks. We also conducted experiments to demonstrate how the impact of the forest surroundings, as well as bounds on ecosystem services, can be evaluated with respect to these trade-offs.

Assessment of different treatment alternatives for patients with total maxillectomy.

To assess the biomechanical advantages of combining zygoma and partial subperiosteal implants for maxillary reconstruction in severely atrophic maxillae, offering potential solutions to the challenges posed by traditional reconstruction methods. A finite element analysis used a craniofacial model simulating a totally resected maxilla. Four treatment scenarios (SCs) were evaluated: SC-1, the quad zygoma approach; SC-2, two zygoma implants (ZIs) and a one-piece subperiosteal implant (SI); SC-3, two ZI and a two-piece SI; and SC-4, four ZI and a one-piece SI. Stress distributions on bone, implants, abutments, and metal frameworks were compared under occlusal forces. For the simulated bone regions under vertical and oblique forces, SC-4 values were higher than SC-1, while SC-2 and SC-3 values were comparable for pmax and pmin. In addition, SC-2 and SC-3 values were lower than those of SC-1 and SC-4. The most balanced von Mises stress values on the ZIsand were observed in SC-3 under vertical and oblique forces. Furthermore, lower von Mises stress values on the abutments were seen in SC-3 under oblique and vertical forces. Although the lower von Mises stress values on the metal frameworks at the lateral incisor and first premolar side were seen in SC-3, lower von Mises values were observed in SC-4 in the first molar region. Overall, this study suggests that combining zygoma and partial subperiosteal implants may be a promising approach for reconstructing severely atrophic maxillae. These implants may offer improved biomechanical properties compared to ZIs alone.

Preferences for Tapering Biologic Disease-Modifying Antirheumatic Drugs Among People With Rheumatoid Arthritis: A Discrete Choice Experiment.

Little is known about the preferences of people with rheumatoid arthritis (RA) regarding tapering of biologic disease-modifying antirheumatic drugs (bDMARDs). The aim of this study was to assess the preferences of people with RA in relation to potential treatment-related benefits and risks of bDMARD tapering and the health care service-related attributes that affect tapering. Participants with RA who had experience taking a bDMARD completed an online discrete choice experiment. Participants were asked their preferences when given three hypothetical treatment scenarios in which varying the frequency of treatment might alter their chance of adverse effects, of regaining disease control, and of other health care service-related effects. Preference weights were estimated using a multinomial logit model. There were 142 complete responses. Reduced dosing frequency of bDMARD treatment had the largest impact on preference (mean 1.0, 95% confidence interval [CI] 0.8-1.2), followed by chance of disease flare (mean 0.7, 95% CI 0.6-0.9). Participants were willing to accept an increased risk of flare between 10.6% (95% CI 3.2-17.9) and 60.6% (95% CI 48.1-72.9) in exchange for benefits associated with tapering bDMARDs. Participants with better quality of life were more likely to choose to remain on current treatment. The predicted uptake of bDMARD tapering was high among people with RA, suggesting bDMARD tapering was a favored option. For individuals with RA, making decisions about tapering bDMARDs involves considering several factors, with the most important determinants identified as dosing frequency and the risk of disease flare. Understanding patient perspectives of bDMARD tapering may enable physicians to make patient-focused shared health care decisions.

Self-supporting three-dimensional CuNi–Sb–SnO2 anode with ultra-long service life for efficient removal of antibiotics in wastewater

Electrochemical ozone production (EOP) is a promising technology for the removal of contaminants in wastewater. However, traditional two-dimensional anodes for EOP are restricted by their reliance on substrates and limited surface area, thus exhibiting poor stability and efficiency. Herein, a novel three-dimensional Sb–SnO2 with Cu and Ni co-doped (3D CuNi-ATO) was synthesized via a facile pressing-sintering method without the Ti substrate. 3D CuNi-ATO had a specific surface area two orders of magnitude higher than conventional CuNi-ATO/Ti, as well as the significant capability of EOP that differs from intrinsic 3D ATO. This endowed 3D CuNi-ATO with the capability to remove tetracycline with a pseudo-first-order rate constant of 0.033 min−1 under a low current density of 5 mA cm−2 within 120 min, which was far more efficient than that by 3D ATO and other two-dimensional anodes reported. The 3D CuNi-ATO was confirmed stable in 100 cycles and had an accelerated service lifetime of over 1100 h versus 83 h of CuNi-ATO/Ti. The degradation of tetracycline in complex matrix and flow-through reactors further revealed the promising potential of 3D CuNi-ATO to be applied in scenarios of practical application and continuous high-rate treatment.

Finite element analysis evaluation of hypothetical alternative treatment scenarios for neglected developmental dysplasia of the hip.

The study aimed to evaluate three different degrees of correction in the surgical treatment of neglected developmental dysplasia of the hip (DDH) using finite element models based on computed tomography. Three tridimensional FEA models of hypothetical post-operative (PO) outcomes were developed, based on three tridimensional CT of a pediatric patient diagnosed with luxated neglected DDH: One with the acetabular index of the contralateral hip (CLAT); another based on a theoretical Bombelli biomechanical model (BMB); and another recreating the patient's actual PO. The stresses in the affected hip were greater than those in the unaffected hip. CLAT showed the greatest stress and the smallest loading zone (LZ). In contrast, BMB showed the smallest stress and the biggest LZs. The approach based on the BMB gave the best results in terms of the distribution of the stresses over the hip, whereas the worst was CLAT. Qualitatively, estimating the stability and range of movement of the hip, the PO case was considered the best.

Consent to voluntary antipsychotic drug treatment-Is it free and informed?

The present research investigates the dynamics of consent in the context of antipsychotic drug therapy, with a particular emphasis on the essential attributes that constitute free and informed consent within medical treatment scenarios. Twenty individuals treated with antipsychotic drugs with consent underwent semistructured interviews. The following major themes were identified: (a) lack or total absence of information regarding the treatment, emphasizing side effects, risks, chances of success, and treatment alternatives. (b) A subjective experience of the lack of free choice that was sometimes also accompanied by the conditioning of psychiatric rehabilitation services or receiving treatment in an open ward by taking antipsychotic medication. The research findings may indicate a problem in obtaining informed consent for antipsychotic treatment that should be addressed. The themes highlight the need to examine the interface between rehabilitation services and psychiatric treatment from the legal and ethical perspective of the autonomy of individuals receiving care. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Machine Learning Models to Predict Early Breakthrough of Recalcitrant Organic Micropollutants in Granular Activated Carbon Adsorbers.

Granular activated carbon (GAC) adsorption is frequently used to remove recalcitrant organic micropollutants (MPs) from water. The overarching aim of this research was to develop machine learning (ML) models to predict GAC performance from adsorbent, adsorbate, and background water matrix properties. For model calibration, MP breakthrough curves were compiled and analyzed to determine the bed volumes of water that can be treated until MP breakthrough reaches ten percent of the influent MP concentration (BV10). Over 400 data points were split into training, validation, and testing sets. Seventeen variables describing MP, background water matrix, and GAC properties were explored in ML models to predict log10-transformed BV10 values. Using the ML models on the testing set, predicted BV10 values exhibited mean absolute errors of ∼0.12 log units and were highly correlated with experimentally determined values (R2 ≥ 0.88). The top three drivers influencing BV10 predictions were the air-hexadecane partition coefficient and hydrogen bond acidity (Abraham parameters L and A) of the MPs and the dissolved organic carbon concentration of the GAC influent water. The model can be used to rapidly estimate the GAC bed life, select effective GAC products for a given treatment scenario, and explore the suitability of GAC treatment for remediating emerging MPs.

Combining High-Resolution Mass Spectrometry and Chemiluminescence Analysis to Characterize the Composition and Fate of Total N-Nitrosamines in Wastewater Treatment Plants.

Monitoring the prevalence and persistence of N-nitrosamines and their precursors in wastewater treatment plants (WWTPs) and effluent-receiving aquatic compartments is a priority for utilities practicing wastewater recycling or exploiting wastewater-impacted source waters. In this work, we developed an analytical framework that combines liquid chromatography-high-resolution mass spectrometry (LC-HRMS) with acidic triiodide-chemiluminescence analysis to characterize the composition and fate of total N-nitrosamines (TONO) and their precursors along the treatment trains of eight WWTPs in New York. Through the parallel application of LC-HRMS and chemiluminescence methods, the TONO scores for 41 N-nitrosamines containing structurally diverse substituents on their amine nitrogen were derived based on their solid-phase extraction recoveries and conversion efficiencies to nitric oxide. Correcting the compositional analysis of TONO using the TONO scores of target N-nitrosamines refined the assessment of the reduction or accumulation of TONO and their precursors across treatment steps in WWTPs. Nontargeted analysis prioritized seven additional N-nitrosamines for confirmation by reference standards, including three previously uncharacterized species: N-nitroso-tert-butylphenylamine, N-nitroso-2-pyrrolidinmethanol, and N-nitrosodesloratadine, although they only served as minor components of TONO. Overall, our study establishes an adaptable methodological framework for advancing the quantitative and qualitative analysis of specific and unknown components of TONO across water treatment and reuse scenarios.

Quantifying the effects of chlorine disinfection on microplastics by time-resolved inductively coupled plasma-mass spectrometry

Using current water treatment systems, significant amounts of microplastics (MPs) are passing through and being released into the aquatic environment. However, we do not clearly know what effects disinfection processes have had on these particles. In this study, we applied inductively coupled plasma-mass spectrometry (ICP-MS) operating in time-resolved analysis (TRA) mode for quantifying changes in the chlorine (Cl) content of MPs under a variety of water treatment scenarios. Our results illustrated that time-resolved ICP-MS offers a potential method for sensitive and direct analysis of Cl content, including Cl mass and chlorine association (%Cl/C), of discrete particles in the MP suspension by the fast sequential measurements of signals from 35Cl1H2 and 12C1H. Our research, across various water treatment scenarios, also showed that polystyrene (PS) MPs exhibited greater reactivity to Cl disinfectant after being pre-disinfected with UV light and in mildly acidic to neutral pH environments. It is noteworthy that about half of the particles in MP suspension exposed to 10 mg Cl2/L, a typical Cl dose applied in water treatment, were chlorinated, and had a Cl content comparable to that of particles subjected to extreme conditions. Of even greater concern is the fact that our cell viability tests revealed that chlorinated MPs induced considerably higher rates of cell death in both human A549 and Caco-2 cells, and that the effects were Cl dose- and polymer type-dependent. Overall, this study demonstrates the potential of time-resolved ICP-MS as a valuable technique for quantifying the Cl content of MP particles, which is crucial to assessing the fate and transformation of MPs in our water supply and treatment systems.