Concentration Rebound Research Articles

Fate of emerging contaminants in an advanced SBR wastewater treatment and reuse facility incorporating UF, RO, and UV processes

A critical factor for widescale water reuse adoption is the capability of advanced wastewater treatment facilities to consistently produce high-quality water by efficiently removing various pollutants, including emerging contaminants (ECs). This study monitored the fate of seventeen ECs (which included pesticides, antibiotics and other pharmaceutically active compounds) over six months in an advanced wastewater reuse facility situated in the United Arab Emirates. The facility integrates a sequencing batch reactor (SBR) based sewage treatment plant (STP) with a water recycling facility featuring ultrafiltration (UF), reverse osmosis (RO), and ultraviolet (UV) disinfection. ECs were detected and quantified at the influent and effluents of the various treatment stages, using an ultra-high-performance liquid chromatography coupled to electrospray ionization and quadrupole time-of-flight mass spectrometry (UHPLC-ESI-QTOF-MS). The STP exhibited variable removal efficiencies, achieving >90 % removal for compounds like caffeine and acetaminophen, while others, such as carbamazepine and thiabendazole, displayed poor removal (<10 %). UF treatment broadly resulted in limited removal, with ECs in permeate typically persisting in the 1–10 ng/L range. Subsequently, after undergoing RO treatment, eight ECs were still detected in the RO permeate, albeit at <1 ng/L, except for imidacloprid (2.5 ng/L). Conversely, the final UV disinfection step led to concentration increases of certain ECs, namely imidacloprid, thiabendazole, sulfamethoxazole, sulfamethazine and caffeine. Overall, the total EC concentration levels decreased considerably from 2300 ng/L in the STP influent to 5.2 ng/L in the RO permeate. However, a subsequent increase to 27.5 ng/L was observed after UV disinfection. While the study underscores the effectiveness of advanced treatment processes, notably RO, in reducing EC concentrations, it also demonstrates the importance of continuous EC monitoring in such facilities as many compounds persist post treatment. Additionally, the potential for processes like UV disinfection to increase certain EC concentrations highlights the need to optimize treatment trains to minimize EC concentration rebound.

Impact of COVID-19 on temporal trends and health risks of urinary metal concentrations among residents of Guangzhou, China

Long-term biomonitoring of urinary metal ions is an essential tool for the epidemiological assessment of chronic exposure levels, enabling us to track changes in metal exposure over time and better understand its health implications. In this study, we evaluated the temporal trends of urinary metal ions among 1962 residents of Guangzhou, China, from 2018 to 2022. The total metal ion concentrations in the urine of the population did not change significantly between 2018 and 2019. With the onset of the COVID-19 pandemic in 2020, urinary total metal ion concentrations began to decline dramatically, reaching their lowest level in 2021. A rebound in concentrations was observed in 2022, which returned to the initial levels observed in 2018. Urine chromium and cadmium concentrations peaked in 2020, while urinary lead levels were the highest in 2021, and urinary nickel concentrations were the highest in 2022. Males consistently displayed higher urinary concentrations of lead and arsenic throughout each year of the study. Furthermore, minors consistently had higher urinary nickel levels than adults, whereas adults consistently had higher urinary cadmium concentrations than minors. Cluster analyses were conducted annually on urinary metal ions to examine the differences in their distribution and to evaluate changes in metal exposure patterns over time. The Monte Carlo simulations indicate that the whole population exhibits a high non-carcinogenic risk from arsenic exposure and significant carcinogenic risks associated with exposure to nickel, arsenic, chromium, and cadmium. The next two years were predicted by a gray prediction model, and the results are tested using mean absolute percentage error which demonstrating high accuracy.

Strong geochemical anomalies following active submarine eruption offshore Mayotte

Submarine volcanic activity releases large amounts of gases and metals in the water column, affecting biogeochemical cycles and ecosystems at a regional and local scale. In 2018, Fani Maoré submarine volcano erupted 50 km offshore Mayotte Island (Comoros Archipelago, Indian Ocean). Active eruptive plumes were observed in May 2019 at and around the summit with acoustic plumes rising 2 km into the water column coupled to strong geochemical anomalies. Between May 2019 and October 2020, three research cruises monitored the eruptive activity. Here, we report spatial and temporal variability of water column chemistry above the volcano, focusing on dissolved gases, trace metal concentrations, and physico-chemical parameters. In May 2019, concentrations above 800 nM in CH4 and H2 were measured throughout the water column, with Total Dissolvable Mn and Total Dissolvable Fe concentrations above 500 nM, and CO2 values of 265 μM. Strong water column acidification was measured (0.6 pH unit) compared to the regional background. From May 2019 to October 2020, we observed a general decrease in gas concentrations, and an evolution of the TDMn/TDFe ratios similar to previously reported values in other submarine volcanic contexts, and consistent with a decrease of the eruptive activity at the volcano. In October 2020, a rebound of high H2 concentrations resulted from new lava flows, which were identified by seafloor observation using deep-towed camera, 5 km further than the volcano summit. During 2 years timespan of our observations (2019–2020), He, CO2 and CH4 concentrations correlate highlighting a magmatic origin of dissolved gases. δ13C-CH4 values of −34‰ vs. vPDB might suggest magma/sediments interaction during the magma ascent, and potential thermal cracking of organic matter, although abiotic methane generation cannot be ruled out given the volcanic context. Weak correlations between H2 and excess of 3He suggest complex processes of H2 from magmatic degassing, lava/seawater interaction, and oxidation processes in the water column. Strong and correlated Fe, Mn and Si water column anomalies are also consistent with fluid-rock reactions induced by acidic fluids rich in magmatic volatiles. Water column acidification appears to be associated with the release of CO2-rich fluids. A year after the main eruptive event, the system seems to be back to steady-state highlighting the buffer capacity and resilience of the seawater column environment.

Population Pharmacokinetic Modeling and Determination of Individual Exposure to Avalglucosidase Alfa in Adolescent and Adult Patients With Late-Onset Pompe Disease: Analysis of Pooled Data From Phase I to III Clinical Trials.

Pompe disease is a rare genetic disorder caused by a deficiency of a lysosomal enzyme called acid alpha-glucosidase and is classified into infantile and late-onset forms. Since 2006, an enzyme replacement therapy involving alglucosidase alfa has been available. In 2021, a new enzyme replacement therapy involving avalglucosidase alfa demonstrated improved clinical benefits. In this article, the authors describe the pharmacokinetics of avalglucosidase alfa using a population pharmacokinetic approach. The population pharmacokinetic model was developed using a data set that included 75 patients and 2042 plasma drug concentrations determined through enzymatic activity assay from 3 studies (phases I/II and III) and involved 3 dose levels (5, 10, and 20 mg/kg). The analysis was performed using NONMEM software. Two sequences were observed in the plasma drug concentration profile: the first kinetic driving exposure, and after 12 hours postdose, a slight rebound addressing very low concentrations that lasted up to 2 weeks. Following model screening, a model with a central compartment with parallel linear and nonlinear elimination and 2 concatenated peripheral compartments was proposed. A putative back-redistribution of a marginal fraction of the drug from the second peripheral compartment to the central compartment may explain the slight rebound in concentration. The final model's mean bias and precision for individual predictions were -2.66% and 30.7%, respectively, and -0.433% and 38.9%, respectively, for population predictions. A concatenated 3-compartment model was developed to describe the avalglucosidase alfa concentrations in patients with late-onset Pompe disease. None of the covariates tested could explain the interindividual variability.

Alirocumab in lipoprotein apheresis: A synergy for patients with high-Lp(a)

Until today lipoprotein apheresis (LA) is considered the most effective treatment for patients with high-Lp(a) and proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) are often combined with LA to dampen the rebound in lipoprotein concentrations. The aim of the present work is to evaluate the effect of dose-adjustment strategy for alirocumab in a small cohort of high-Lp(a) subjects with ischemic heart disease and in chronic LA treatment. Chronic LA effect on Lp(a) levels is a significant reduction in pre-LA Lp(a) concentrations compared to native Lp(a) value (118 [116–119] mg/dl vs 150 [137–155] mg/dl; p < 0.001). Furthermore, the administration of Arilocumab 75 mg after 7 days from LA shows a significant pre-LA reduction in the Lp(a) concentrations respect to those obtained with administration immediately after the LA treatment. In high-Lp(a) patients treated with chronic LA the deferred addition of alirocumab, resulted in lower LDL-cholesterol and Lp(a) values.

Development of a population pharmacokinetics and pharmacodynamics model of glucarpidase rescue treatment after high-dose methotrexate therapy.

Glucarpidase (CPG2) reduces the lethal toxicity of methotrexate (MTX) by rapid degradation. In this study, a CPG2 population pharmacokinetics (popPK) analysis in healthy volunteers (phase 1 study) and a popPK-pharmacodynamics (popPK-PD) analysis in patients (phase 2 study, n = 15) who received 50 U/kg of CPG2 rescue for delayed MTX excretion were conducted. In the phase 2 study, the first CPG2 treatment at a dose of 50 U/kg was intravenously administered for 5min within 12h after the first confirmation of delayed MTX excretion. The second dose of CPG2, with a plasma MTX concentration >1 μmol/L, was administered to the patient more than 46h after the start of CPG2 administration. The population mean PK parameters (95% CI) of MTX, obtained from the final model post hoc, were estimated as follows: CLrMTX = 2.424 L/h (95% CI: 1.755-3.093), VcMTX = 12.6 L (95% CI: 10.8-14.3), VpMTX = 2.15 L (95% CI: 1.60-2.70), and α = 8.131 x 105 (4.864 x 105-11.398 x 105). The final model, including covariates, was CLrMTX (L/h): 3.248 x Body Weight/Serum creatinine/60 (CV 33.5%), VcMTX (L): 0.386 x Body Weight/body surface area (CV 29.1%), VpMTX (L):3.052 x Body Weight/60 (CV 90.6%), and α (L/h): 6.545 x 105 (CV 79.8%). These results suggest that the pre-CPG2 dose and 24h after CPG2 dosing were the most important sampling points in the Bayesian estimation of plasma MTX concentration prediction at 48h. These CPG2-MTX popPK analysis and Bayesian estimation of rebound in plasma MTX concentrations are clinically important to estimate >1.0 μmol/L 48h after the first CPG2 dosing. https://dbcentre3.jmacct.med.or.jp/JMACTR/App/JMACTRS06/JMACTRS06.aspx?seqno=2363, identifier JMA-IIA00078 and https://dbcentre3.jmacct.med.or.jp/JMACTR/App/JMACTRS06/JMACTRS06.aspx?seqno=2782, identifier JMA-IIA00097.

In‐situ application of colloidal activated carbon for PFAS‐contaminated soil and groundwater: A Swedish case study

AbstractSoil and groundwater contamination by per‐ and polyfluoroalkyl substances (PFAS) has been a significant concern to human health and environmental quality. Remediation of contaminated sites is crucial to prevent plume expansion but can prove challenging due to the persistent nature of PFAS combined with their high aqueous mobility. In this case study, we investigated the potential of colloidal activated carbon (CAC) for soil stabilization at the pilot scale, aiming to entrap PFAS and prevent their leaching from soil into groundwater. Monitoring of the site revealed the presence of two potential sources of PFAS contamination at concentrations up to 23 μg L−1 for ∑11PFAS in groundwater. After CAC application, initial results indicated a 76% reduction of ∑11PFAS and high removal rates for long‐chain PFAS, such as perfluorooctane sulfonic acid and perfluorooctanoic acid. A spike in concentrations was noticed 6 months after injection of CAC, showing a rebound of the plume and a reduction of treatment effectiveness. Based on long‐term monitoring data, the treatment effectiveness for ∑11PFAS dropped to 52%. The rebound of concentrations was attributed to the plume bypass of the barrier due to the presence of high conductivity zones, which likely occurred because of seasonal changes in groundwater flow directions or the CAC application at the site. This demonstrates the need for a detailed and accurate hydrogeological understanding of contaminated sites before designing and applying stabilization techniques, especially at sites with high geologic and hydrologic complexity. The results herein can serve as a guideline for treating similar sites and help avoid potential pitfalls of remedial efforts.

Changes in Air Quality and Drivers for the Heavy PM2.5 Pollution on the North China Plain Pre- to Post-COVID-19.

Under the clean air action plans and the lockdown to constrain the coronavirus disease 2019 (COVID-19), the air quality improved significantly. However, fine particulate matter (PM2.5) pollution still occurred on the North China Plain (NCP). This study analyzed the variations of PM2.5, nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), and ozone (O3) during 2017–2021 on the northern (Beijing) and southern (Henan) edges of the NCP. Furthermore, the drivers for the PM2.5 pollution episodes pre- to post-COVID-19 in Beijing and Henan were explored by combining air pollutant and meteorological datasets and the weighted potential source contribution function. Results showed air quality generally improved during 2017–2021, except for a slight rebound (3.6%) in NO2 concentration in 2021 in Beijing. Notably, the O3 concentration began to decrease significantly in 2020. The COVID-19 lockdown resulted in a sharp drop in the concentrations of PM2.5, NO2, SO2, and CO in February of 2020, but PM2.5 and CO in Beijing exhibited a delayed decrease in March. For Beijing, the PM2.5 pollution was driven by the initial regional transport and later secondary formation under adverse meteorology. For Henan, the PM2.5 pollution was driven by the primary emissions under the persistent high humidity and stable atmospheric conditions, superimposing small-scale regional transport. Low wind speed, shallow boundary layer, and high humidity are major drivers of heavy PM2.5 pollution. These results provide an important reference for setting mitigation measures not only for the NCP but for the entire world.

Total Hemoglobin Trajectories from Pregnancy to Postpartum in Rural Northeast Brazil: Differences between Adolescent and Adult Women.

This study examines total hemoglobin (THB) trajectories during pregnancy and postpartum and associated factors among adolescents and adults from a low-income community. This is an observational, longitudinal study, part of the Adolescence and Motherhood Research (AMOR) project, performed between 2017 and 2019 in the Trairi region of Rio Grande do Norte state, Brazil. The THB levels of 100 primigravida adolescents and adults were monitored up to 16 weeks of gestation, in the third trimester, and 4–6 weeks postpartum, along with socioeconomic characteristics, anthropometrics, and health-related variables. Mixed-effect linear models evaluated the trajectories of THB and the associated factors. THB levels decreased between first and second assessments and increased between the second and postpartum assessments. For the adolescent cohort, the rebound in THB concentration between the third trimester and postpartum was not enough to make up for the initial losses, as occurred in the adult cohort. For the adult group, higher THB levels were associated with pregnancy planning and good self-rated health. Race was marginally associated to THB levels, with black/brown women presenting higher concentrations in the adolescent and lower concentration in the adult group. Special attention to prenatal care among pregnant adolescents should consider their higher risk of anemia and its negative effects.

Optimal indicator for changing the filter during the continuous renal replacement therapy in intensive care unit patients with acute kidney injury: A crossover randomized trial.

The study aims to investigate an optimal indicator for changing the filter during the continuous renal replacement therapy (CRRT) in intensive care unit (ICU) patients with acute kidney injury (AKI). Patients with AKI requiring CRRT in an ICU were randomly divided into two groups for crossover trial, i.e., groups A and B. Patients in the group A were firstly treated with continuous veno-venous hemofiltration (CVVH), followed by continuous veno-venous hemodiafiltration (CVVHDF). Patients in the group B were firstly treated with CVVHDF followed by CVVH. Delivered doses of solutes with different molecular weights at the indicated time points between groups were compared. A correlation analysis between the delivered dose and pre-filter pressure (PPRE) and transmembrane pressure (PTM) was performed. Receiver operating characteristic (ROC) curves were constructed to evaluate the accuracy of PTM as an indicator for filter replacement. A total of 50 cases were analyzed, 27 in the group A and 23 in the group B. Delivered doses of different molecular-weight solutes significantly decreased before changing the filter in both modalities, compared with those at the initiation of treatment (all P<0.05). In the late stage of CRRT, the possible rebound of serum medium-molecular-weight solute concentration was observed. PTM was negatively correlated with the delivered dose of medium-molecular-weight solute in both modalities. The threshold for predicting the rebound of serum concentration of medium-molecular-weight solute by PTM was 146.5 mmHg (1 mmHg=0.133 kPa). The filter can be used as long as possible within the manufacturer's safe use time limits to remove small-molecular-weight solutes. PTM of 146.5 mmHg may be an optimal indicator for changing the filter in CRRT therapies to remove medium-molecular-weight solutes.

The Influence of Outdoor Particulate Matter PM2.5 on Indoor Air Quality: The Implementation of a New Assessment Method

Epidemiological research has shown that there is a positive correlation between the incidence of disease and mortality in humans and the mass concentration of particulate matter. An average 1 g of suspended dust emitted in a room results in the same exposure as 1 kg emitted to the outside air. In this study, the authors described the state of knowledge on dust pollution inside and outside buildings (I/O ratios), and methods of testing the PM infiltration process parameters. According to the law of indoor–outdoor particle mass balance and the physical basis of aerosol penetration theory, a relatively simple but new method for estimating the penetration factor P was tested. On the basis of the curve of dynamic changes of internal dust concentration in the process of particle concentration decay and next of the followed curve of dynamic rebound of particle concentration, authors measured penetration factor of ambient PM2.5 through building envelope. Authors modification of the method is to be used for determining the value of the particle deposition rate k not from the course of the characteristics in the transient state (the so-called particle concentration decay curves) but from the concentration rebound course, stimulated by natural particle infiltration process. Recognition measurements of the mass concentration of suspended PM2.5 and PM10 particles inside the rooms were carried out. In this study, the choice of the prediction particle penetration factor P calculation method was supported by the exemplary calculation of the p value for a room polluted by PM2.5. The preliminary results of the penetration factors determined by this method P = 0.61 are consistent with the P factor values from the literature obtained so far for this dimensional group of dusts.

Enhanced Recovery of Per- and Polyfluoroalkyl Substances (PFASs) from Impacted Soils Using Heat Activated Persulfate.

Varying transport potential of cationic, zwitterionic, and anionic per- and polyfluoroalkyl substances (PFASs) may pose challenges for remediation of aqueous film forming foam (AFFF) impacted sites, particularly during groundwater extraction. Slow desorption of stronger sorbing, zwitterionic, and cationic PFASs may cause extended remediation times and rebound in aqueous PFAS concentrations. Persulfate oxidation has the potential to convert a complex mixture of PFASs into a simpler and more recoverable mixture of perfluoroalkyl acids (PFAAs). AFFF-impacted soils were treated with heat-activated persulfate in batch reactors and subjected to 7-day leaching experiments. Soil and water were analyzed using a combination of targeted and high resolution liquid chromatography mass spectrometry techniques as well as the total oxidizable precursors assay. Following oxidation, total PFAS composition showed the expected shift to a higher fraction of PFAAs, and this led to higher total PFAS leaching in pretreated reactors (108-110%) vs control reactors (62-90%). In both pretreated and control soils, precursors that remained following leaching experiments were 61-100% cationic and zwitterionic. Results suggest that persulfate pretreatment of soils has promise as an enhanced recovery technique for remediation of total PFASs in impacted soils. They also demonstrate that PFAS distribution may have been altered at sites where in situ chemical oxidation was applied to treat co-occurring contaminants of concern.

Persulfate-based controlled release beads for in situ chemical oxidation of common organic pollutants

Groundwater contamination by organic pollutants is a growing threat to the environment and human health. As a cost-effective method, in situ chemical oxidation (ISCO) treatment has become a popular technical method to degrade groundwater pollutants. However, conventional ISCO treatment can suffer from a number of operational issues, such as tailing and concentration rebound, and thus the long-term treatment effectiveness is less desirable. As an alternative approach to the conventional ISCO method, controlled release materials are designated to gradually release oxidant chemicals to treat polluted groundwater with an extended chemical release duration and a reduced peak release rate. In this study, novel persulfate-paraffin based controlled release bead (CRB) materials were prepared and tested in a laboratory setting for their applicability in groundwater organic pollution remediation. It shows that bead size and temperature can substantially affect the release kinetics of persulfate from the CRBs, while the impact of solution pH and the presence of matrix anions are insignificant. Moreover, degradation experiments of benzene, toluene, ethylbenzene, and xylene pollutants show that the performance of CRBs, particularly within a short period after being delivered in situ, is on par with the conventional ISCO method using aqueous persulfate. This study expands our understanding and capacity in adopting controlled release materials for groundwater remediation. This study promotes the potential field application of such novel controlled release materials for environmental remediation of groundwater.

Rare-Earth Elements as Natural Tracers for In Situ Remediation of Groundwater.

The utility of rare-earth elements (REEs) as natural geochemical tracers for the analysis of groundwater remediation was examined in several example permeable reactive barriers (PRBs). The PRBs utilize zero-valent iron and organic carbon plus limestone mixtures for contaminant treatment. Zero-valent iron removed REEs from groundwater to below detection levels (2-4 ng/L) and subsequent rebound of REE concentrations in regions down-gradient of the treatment zones was not observed. In addition, REE concentrations within and down-gradient of an organic carbon/limestone PRB were significantly reduced to <1% of influent levels. Thus, REEs are sensitive tracers for evaluating the interaction of groundwater with materials placed in the subsurface for contaminant remediation. Analysis of geochemical tracers for understanding in situ remediation becomes important in situations where down-gradient contaminant concentrations fail to decrease within expected timeframes. The field data indicated that increased solid-phase partitioning of REEs occurred with increasing pH and heavy REEs were preferentially removed compared to light REEs in ZVI systems. In the organic carbon PRB, unexpected negative europium anomalies were observed, revealing new information about redox conditions within the treatment zone. REE concentrations and shale-normalized profiles can be used as natural tracers to better understand in situ technologies for groundwater remediation.

Pharmacokinetics of Vancomycin in Critically Ill Patients Undergoing Sustained Low-Efficiency Dialysis.

Vancomycin pharmacokinetic data in critically ill patients receiving sustained low-efficiency dialysis (SLED) is limited. Published data using vancomycin with intermittent hemodialysis and continuous renal replacement therapy may not be applicable to hybrid dialysis modalities such as SLED. Current drug references lack recommendations for vancomycin dosing in patients receiving SLED. The objective of this study was to determine vancomycin pharmacokinetics during SLED. A total of 20 patients who were critically ill with oliguric or anuric renal failure who received vancomycin and SLED were included in the study. Surrounding one SLED session, serum vancomycin blood samples were drawn before the initiation of SLED, at the termination of SLED, and 4hours after completion of SLED treatment. Following this, patients received vancomycin, dosed to target a goal peak of 20-30mcg/ml. A vancomycin peak level was drawn 1hour after the end of the infusion. SLED treatment duration was at least 7hours. Continuous data are reported as median (interquartile range) and categorical data as percentage. The vancomycin elimination rate and half-life were 0.051hours (0.042-0.074 hours) and 13.6hours (9.4-16.6 hours), respectively. SLED reduced vancomycin serum concentrations by 35.4% (31.5-43.8%), and vancomycin rebound was 9.8% (2.5-13.7%). The vancomycin dose administered post-SLED was 1000mg (875-1125 mg). For 18 patients, the patient-specific volume of distribution was 0.88L/kg (0.67-1.1 L/kg), vancomycin clearance was 3.5L/hr (2.2-5.2 L/hr), and the area under the concentration-time curve during the study time period was 280.8mg·hr/L (254.7-297.3 mg·hr/L). Vancomycin is significantly removed during SLED with little rebound in serum concentrations 4hours after completion of SLED. Based on study findings, patients who are critically ill require additional vancomycin dosing after each SLED session to maintain therapeutic post-SLED vancomycin concentrations. Therapeutic drug monitoring of vancomycin is recommended during SLED.

P1113TREATMENT OF ACUTE LITHIUM INTOXICATION WITH SUSTAINED LOW-EFFICIENCY DIALYSIS (SLED)

Abstract Background and Aims Lithium salts are widely used in psychiatry for prophylaxis and treatment of bipolar affective disorders. Given its narrow therapeutic range, drug overdosage is not infrequent, and lithium intoxication has potentially fatal neurologic and cardiac side effects. Owing to its low molecular weight (7 Da), relatively small volume of distribution, and its negligible protein binding, lithium can be efficiently removed by any extracorporeal modality of renal replacement therapy (RRT). Although conventional intermittent haemodialysis (IHD) is effective in promptly cleating lithium, postdialysis rebound is common. The use of sustained low-efficiency dialysis (SLED) in lithium intoxication seems to be a valid therapeutic strategy, but strong evidence is still lacking in the literature. We present here two cases of lithium intoxication, in one case acute (naïve patient) and in the other case acute-on-chronic (a deliberate overdose in a patient previously on lithium therapy), successfully treated with SLED. Method: Patient A - A 47 years-old woman without history of lithium consumption was admitted to the ER. after a voluntary acute lithium ingestion of 40 tablets of lithium carbonate (8.12 mEq lithium each). Notwithstanding treatment with intravenous crystalloids and gastric lavage, lithium concentration increased up to 4.18 mEq/l at about 24 h after admission. She developed mental status changes, oliguria, hypotension and bradycardia. Patient B – A 58 years-old man on lithium therapy for bipolar syndrome was admitted to ER after a voluntary acute lithium ingestion of an unknown quantity of lithium carbonate tablets. Lithium concentration, after an initial level of 0.4 mEq/L, increased up to 4.35 mEq/l about 15 h from admission, despite irst-line therapies with intravenous crystalloids and gastric lavage were promptly started. His mental status worsened, together with oliguria, bradycardia and hypotension. Results: Patient A - A 8-hour SLED session with regional citrate anticoagulation (RCA) was planned [blood flow rate (Qb) 200 mL/min; dialysis fluid rate (Qd) 300 mL/min; countercurrent flow direction]. Lithium serum levels decreased by 87% during treatment (0.55 mEq/L), and the patient fully awoke recovering a normal mental status within the first 4 h of treatment. SLED was completed safely within the prescribed time. After the end of treatment, lithium rebound was unremarkable and renal function completely recovered and the patients was discharged after 3 days. Patient B - A 12-hour SLED session with RCA was planned (Qb 200 mL/min; Qd 500 mL/min; countercurrent flow direction). Serum lithium levels decreased by 55% (2.10 mEq/L) during treatment, and the patient awoke, recovering a normal mental status. At the end of treatment, rebound of lithium concentration was observed at 4 hours from SLED end detected (from 2.1 to 2.5 mEq/L), with initial signs of mental deterioration. A second SLED (12 h) was performed, with the same operative parameters and, by the end of the second treatment, lithium concentration was 0.49 mEq/L. Afterward, mental status and renal function fully recovered and no rebound rebound was observed. The patient was discharged after 6 days. Conclusion SLED could represent a good therapeutic strategy to treat acute lithium intoxication, providing an initial rapid clearance with resolution of symptoms, and limiting major rebound.

Niacin nutrition and rumen-protected niacin supplementation in dairy cows: an updated review.

As the precursor to NAD+ and NADP+, niacin is important for catabolic and anabolic redox reactions. In addition, niacin is known for its anti-lipolytic action via a hydroxycarboxylic acid-2-receptor-dependent mechanism. The anti-lipolytic effects of traditional free niacin supplementation during transition periods had been studied extensively, but the reported effects are ambiguous. In the past decade, a series of studies were conducted to evaluate the effects of rumen-protected niacin (RPN) on production performance and metabolic status in early lactation and on heat stress in dairy cows. Feeding RPN seems more effective than free niacin regarding increasing circulating niacin concentration. The rebound of plasma NEFA was found after termination of niacin abomasal infusion. Feeding RPN or infusion of niacin via the abomasum could suppress lipolysis and reduce insulin resistance in early lactation. Additionally, RPN supplementation could possibly relieve heat stress through vasodilation during moderate to severe heat stress condition. However, these beneficial effects of niacin supplementation have not always been observed. The inconsistent results across studies may be related to dosages of niacin supplementation, rebound of plasma NEFA concentration, stage of lactation or severity of heat stress. Overall, the current review is to present updated information on niacin nutrition in dairy cows and the recommendations are given for future research.

A Real-Time Continuous Glucose Monitoring-Based Algorithm to Trigger Hypotreatments to Prevent/Mitigate Hypoglycemic Events.

Background: The standard treatment for hypoglycemia recommended by the American Diabetes Association (ADA) suggests patients with diabetes to take small amounts of carbohydrates, the so-called hypotreatments (HTs), as soon as blood glucose concentration goes below 70 mg/dL. However, prevention, or at least mitigation, of hypoglycemic events could be achieved by triggering HTs ahead of time thanks to the use of the predictive capabilities of suitable real-time algorithms fed by continuous glucose monitoring (CGM) sensor data. Materials and Methods: The algorithm proposed in this article to trigger HTs for preventing forthcoming hypoglycemic events is based on the computation of the "dynamic risk", there is a nonlinear function combining current glycemia with its rate-of-change, both provided by CGM. A comparison of performance of the proposed algorithm against the ADA guidelines is made, in silico, on datasets of 100 virtual patients undergoing a single-meal experiment, with induced postmeal hypoglycemia, generated by the UVA/Padova type 1 diabetes simulator. Results: On noise-free CGM data, the proposed algorithm reduces the time spent in hypoglycemia, on median [25th-75th percentiles] from 36 [29-43] to 0 [0-11] min (P < 0.0001), with a concomitant decrease of the post-treatment rebound (PTR) in glucose concentration, on median [25th-75th percentiles] from 136 [121-148] to 121 [116-127] mg/dL (P < 0.0001). On noisy CGM data, there is still a reduction of both time spent in hypoglycemia from 41 [28-49] min to 25 [0-41] min (P < 0.0001) and PTR from 174 [146-189] mg/dL to 137 [123-151] mg/dL (P < 0.0001). Conclusions: The potentiality of the new algorithm in generating preventive HTs, which can allow significant reduction of hypoglycemia without concomitant increase of hyperglycemia, suggests its further development and test in silico, for example, simulating both insulin pump and multiple-daily-injection therapies.

An interpretation to Cr(Ⅵ) leaching concentration rebound phenomenon with time in ferrous-reduced Cr(Ⅵ)-bearing solid matrices.

Toxicity characteristic leaching procedure (TCLP) is a prevalent way to evaluate the treatment effectiveness for Cr(Ⅵ)-bearing solid matrices (CBSM). But when a certain amount of residual reductants are present in the treated CBSM, Cr(Ⅵ) leaching concentration rebound phenomenon (CLCRP) occurs, which invalidates the TCLP. This study explores the microstructure of ferrous-reduced CBSM and proves that the residual Cr(Ⅵ), FexCr1-x(OH)3 precipitate and residual ferrous are separately distributed in a three-layer structure. In natural scenarios, the residual ferrous in the out-layer is firstly flushed away by rainfall and groundwater or oxidized by dissolved oxygen, resulting in the decrease of ferrous with time. Residual Cr(Ⅵ), due to being blocked by precipitate layer, is less flushed away. While in TCLP, all of released residual ferrous and Cr(Ⅵ) are in the leachate and react till one of them is almost exhausted, resulting in the underestimation of Cr(Ⅵ) leaching concentrations. The longer the samples experience the natural scenarios, the less of the residual ferrous, resulting in the decline of underestimation of Cr(Ⅵ) leaching concentrations with time. This study also provides a pretreatment which can effectively reduce the residual ferrous, achieving more accurate Cr(Ⅵ) leaching concentrations and eliminating CLCRP.

Analytical and Numerical Modeling of Solute Intrusion, Recovery, and Rebound in Fractured Bedrock.

Contaminated groundwater in fractured bedrock can expose ecosystems to undesired levels of risk for extended periods due to prolonged back-diffusion from rock matrix to permeable fractures. Therefore, it is key to characterize the diffusive mass loading (intrusion) of contaminants into the rock matrix for successful management of contaminated bedrock sites. Even the most detailed site characterization techniques often fail to delineate contamination in rock matrix. This study presents a set of analytical solutions to estimate diffusive mass intrusion into matrix blocks, it is recovered by pumping and concentration rebound when pumping ceases. The analytical models were validated by comparing the results with (1) numerical model results using the same model parameters and (2) observed chloride mass recovery, rebound concentration, and concentration in pumped groundwater at a highly fractured bedrock site in Alberta, Canada. It is also demonstrated that the analytical solutions can be used to estimate the total mass stored in the fractured bedrock prior to any remediation thereby providing insights into site contamination history. The predictive results of the analytical models clearly show that successful remediation by pumping depends largely on diffusive intrusion period. The results of initial mass from the analytical model was used to successfully calibrate a three-dimensional discrete fracture network numerical model further highlighting the utility of the simple analytical solutions in supplementing the more detailed site numerical modeling. Overall, the study shows the utility of simple analytical methods to support long-term management of a contaminated fractured bedrock site including site investigations and complex numerical modeling.