Dyslipidemia and heart failure: current evidence and perspectives of use of statins

Heart failure (HF) is a condition with growing morbidity and mortality. Dyslipidemia in HF is not concentrated around hypercholesterolemia as in coronary artery disease. As a corollary, the robust benefits seen with statins across the spectrum of CAD have not been replicated in HF. Multiple potential pleiotropic effects of statins include anti-inflammatory, antioxidant, endothelial stabilization, antiapoptotic, anti-thrombotic, and modulation of the autonomic system apart from lipid lowering. These benevolent actions need to be counterbalanced with the potential derangement of ubiquinone, selenoprotein and endotoxin pathways. While small randomized and non-randomized studies demonstrated a multitude of benefits in clinical and surrogate endpoints, two large RCTs failed to demonstrate unequivocal benefits. However, multiple large meta-analyses do demonstrate definite improvement in clinical endpoints including death and heart failure hospitalization. The clinical likelihood of benefit was higher in younger patients with less advanced HF and use of lipophilic statins.

Staphylococcus epidermidis is a safer surrogate of Staphylococcus aureus in testing bacterial filtration efficiency of face masks

Face masks play a role in reducing the spread of airborne pathogens, providing that they have a good filtration performance, are correctly fitted and maintained. Bacterial Filtration Efficiency (BFE) is a key indicator for evaluating filtration performance according to both European and US standards, requiring the use of Staphylococcus aureus loaded aerosol. However, the generation and handling of a Biohazard group 2 bacterium aerosol require a careful management of the biological risk and pose limitations to the accessibility to this method. To mitigate these drawbacks, we investigated the use of S. epidermidis ATCC 12228, a Biohazard group 1 bacterium, as surrogate in BFE test. To this end, tests with the surrogate strain were performed to tune the method. Then, three face mask models, representative for both surgical and community masks, were tested according to the standard method and then using an aerosolized suspension of S. epidermidis. BFE% values were calculated for each mask model and tested microorganisms. Results showed that BFE test can be performed using the S. epidermidis instead of S. aureus, preserving results validity and turnaround time, but reducing residual risk for laboratory operators.

Mobility of crocidolite asbestos in sandy porous media mimicking aquifer systems

Asbestos is widely recognized as being a carcinogen when dispersed in air, but very little is known about its exposure pathways in water and its subsequent effects on human health. Several studies have proved asbestos presence in groundwater but failed to assess its mobility in aquifer systems. This paper aims to fill this gap by studying the transport of crocidolite, an amphibole asbestos, through sandy porous media mimicking different aquifer systems. To this purpose, two sets of column test were performed varying the crocidolite suspension concentration, the quartz sand grain size distribution, and the physicochemical water parameters (i.e., pH). The results proved that crocidolite is mobile in quartz sand due to the repulsive interactions between fibres and porous media. The concentration of fibres at the outlet of the column were found to decrease when decreasing the grain size distribution of the porous medium, with a bigger impact on highly concentrated suspensions. In particular, 5-to-10-µm-long fibres were able to flow through all the tested sands while fibres longer than 10 µm were mobile only through the coarser medium. These results confirm that groundwater migration should be considered a potential exposure pathway while implementing human health risk assessment.

Unraveling the invisible demon: a study of the oxidative stress markers, antioxidant activities and inflammatory markers in patients admitted with complete heart block

Funding Acknowledgements

Type of funding sources: None.

Introduction

Despite the recent advancements in the management of Complete Heart Block (CHB), the aetiology of CHB is still idiopathic in most of the cases. Our study explores this hitherto untouched aspect of complete heart block.

Purpose

We aimed to assess the aetiological profile of Complete Heart Block patients in our study.

Methods

The study population consisted of 60 patients with complete heart block aged between 30 to 80 years, attending as an inpatient in ER. Oxidative stress was measured by serum MDA, serum GSH, serum Catalase activity and serum SOD activity. Antioxidant activity was obtained by measuring the levels of serum total antioxidant capacity. Inflammatory stress was measured by IL-5 and TNF-alpha levels. These values were compared to 30 healthy controls with no prior history of smoking and diabetes mellitus.

Results

The mean age of the patient was 62.48 ± 7.98 years and the gender distribution was 37 males and 23 females out of 60 patients. The mean value of serum MDA (ng/mL) in cases is 1451.26 ± 206.32, and in controls, the mean value is 1197.98 ± 234.71 (p=<0.001). The mean value of serum GSH (mcg/mL) in cases is 46.982 ± 18.613, and in controls, the mean value is 54.155 ± 10.762 (p=0.027). The mean value of serum Catalase Activity (U/min/mg protein) in cases is 10.763 ± 4.038 and in controls, the mean value is 19.878 ± 7.787 (p=0.003). The mean value of serum SOD Activity (U/g) in cases is 24.950 ± 5.4565, and in controls, the mean value is 46.214 ± 14.6309 (p=0.891). The mean value of serum Total Antioxidant Capacity (U/mL) in cases is 5.546 ± 0.620 and in controls, the mean value is 8.346 ± 2.781 (p=0.025). The mean value of serum IL-5 (pg/mL) in cases is 481.442 ± 28.8995, and in controls, the mean value is 67.347 ± 20.445 (p<0.001). The mean value of serum TNF-ALFA (pg/mL) in cases is 196.741 ± 73.771, and in controls, the mean value is 144.530 ± 42.599 (p= 0.081).

Conclusions

During a complete heart block, SOD (p=0.891), CAT (p=0.003), GSH (p=0.027) and total antioxidant (TAOC) (p=0.025) were significantly decreased in cases, compared to healthy controls, thus suggesting that the elevated levels of oxidative free radicals causes endothelial dysfunctioning. The increase in ROS was observed by a highly significant increase of malondialdehyde (MDA) (p=<0.001) showing high ROS-mediated tissue damage. Besides damage by oxidative stress, our study suggests that there are certain inflammatory markers like TNF-α and IL-5 that actively participate in causing heart block. There was a significant increase in the concentration of IL-5 (p<0.001) in the cases as compared to the controls.

The surprises in optical coherence tomography (OCT) findings in patients presenting with in-stent restenosis: the road less travelled

Funding Acknowledgements

Type of funding sources: None.

Background

Morphological features of neointimal tissue play a pivotal role in the pathophysiology of In-Stent Restenosis (ISR) after percutaneous coronary intervention, hence understanding these features and patterns is crucial.

Purpose

The present study was designed to qualitatively and quantitatively assess neointimal characteristics of lesions using OCT in patients presenting with ISR.

Methods

This was a single-center, prospective, observational study performed between 1st August 2020 and 30th December 2021 at a tertiary-care center in India. Patients diagnosed with stable angina and acute coronary syndrome with post-procedural angiographically documented restenosis (>50%) were included. Qualitative and quantitative assessment of neointimal hyperplasia patterns was performed using OCT.

Results

A total of 34 patients with ISR were studied. Neointimal hyperplasia was classified as (i) homogenous group (n=18) and (ii) non-homogenous group (n=16). As many as 14 (77.8%) diabetics belonged to the homogenous group. Predominant plaque characteristics such as neoatherosclerosis, cholesterol crystals, and calcium were documented in 14 (77.8%), 12 (66.7%), and 11 (61.1%) patients in the homogenous group and in 10 (62.5%), 10 (62.5%), and 9 (56.2%) patients in the non-homogenous group, respectively. Unexpanded stent struts were identified in 11 (61.1%) and 11 (68.8%) patients in the homogenous and non-homogenous groups, respectively. Mean strut thickness was 93.73 ± 31.03 µm and 83.54 ± 18.0 µm, ISR was 72.50 ± 15.93% and 65.37 ± 21.69%, the neointimal thickness was 588.06 ± 167.82 mm and 666.25 ± 218.05 mm, and neointimal hyperplasia was 54.54 ± 11.23% and 59.26 ± 8.86% in the homogenous and non-homogenous groups, respectively.

Conclusion

Neoatherosclerosis and stent underexpansion was predominantly observed in our study, which was in contrast to most of the existing literature [1,2,3], and only diabetes was found to be significantly associated with homogenous neointimal hyperplasia, irrespective of the generation of the stent.

Electrokinetic delivery of permanganate in clay inclusions for targeted contaminant degradation

The use of electrokinetics (EK) has great potential to deliver reactants in impervious porous media, thus overcoming some of the challenges in the remediation of contaminants trapped in low-permeability zones. In this work we experimentally investigate electrokinetic transport in heterogeneous porous media consisting of a sandy matrix with a target clay inclusion. We demonstrate the efficient EK-delivery of permanganate in the target clay zone (transport velocity 0.3-0.5 m day^-1) and its reactivity with Methylene Blue, a positively charged contaminant trapped within the inclusion. The delivery method was optimized using a KH₂PO₄/K₂HPO₄ buffer to attenuate the effect of electrolysis reactions in the electrode chambers, thus mitigating the propagation of pH fronts and preventing the phenomenon of permanganate stalling. The experiments showed that the buffer electrical conductivity greatly impacts the potential gradient in the heterogeneous porous medium with implications on the observed rates of electrokinetic transport (variation up to 40%). The reactive experiments provided direct evidence of the permanganate penetration within the clay and of its capability to degrade the target immobilized contaminant. The experimental results were analyzed using a process-based model, elucidating the governing transport mechanisms and highlighting the effect of different mass transfer processes on conservative and reactive electrokinetic transport.

Nanoplastics removal during drinking water treatment: Laboratory- and pilot-scale experiments and modeling

Microplastics detected in potable water sources and tap water have led to concerns about the efficacy of current drinking water treatment processes to remove these contaminants. It is hypothesized that drinking water resources contain nanoplastics (NPs), but the detection of NPs is challenging. We, therefore, used palladium (Pd)-labeled NPs to investigate the behavior and removal of NPs during conventional drinking water treatment processes including ozonation, sand and activated carbon filtration. Ozone doses typically applied in drinking water treatment plants (DWTPs) hardly affect the NPs transport in the subsequent filtration systems. Amongst the different filtration media, NPs particles were most efficiently retained when aged (i.e. biofilm coated) sand was used with good agreements between laboratory and pilot scale systems. The removal of NPs through multiple filtration steps in a municipal full-scale DWTP was simulated using the MNMs software code. Removal efficiencies exceeding 3-log units were modeled for a combination of three consecutive filtration steps (rapid sand filtration, activated carbon filtration and slow sand filtration with 0.4-, 0.2- and 3.0-log-removal, respectively). According to the results from the model, the removal of NPs during slow sand filtration dominated the overall NPs removal which is also supported by the laboratory-scale and pilot-scale data. The results from this study can be used to estimate the NPs removal efficiency of typical DWTPs with similar water treatment chains.

Exploring the potential of graphene oxide nanosheets for porous media decontamination from cationic dyes

Graphene oxide (GO) nanosheets, often embedded in nano-composites, have been studied as promising materials for waste water purification, in particular to adsorb heavy metals and cationic organic contaminants. However, a broader range of potential applications of GO is still unexplored. This work investigated the potential applicability of GO for enhanced in-situ soil washing of secondary sources of groundwater contamination (i.e. the controlled recirculation of a washing GO suspension via injection/extraction wells). The laboratory study aimed at quantifying the capability of GO to effectively remove adsorbed methylene blue (MB) from contaminated sand. The tests were conducted in simplified conditions (synthetic groundwater at NaCl concentration of 20 mM, silica sand) to better highlight the key mechanisms under study. The results indicated a maximum sorption capacity of 1.6 mgMB/mgGO in moderately alkaline conditions. Even though the adsorption of MB onto GO slightly reduced the GO mobility in the porous medium, a breakthrough higher than 95% was obtained for MB/GO mass ratios up to 0.5. This suggests that a very high recovery of the injected particles should be also expected in the field.

Instantaneous wave-free ratio and fractional flow reserve: effect of variation in left ventricular end diastolic pressure

Funding Acknowledgements

Type of funding sources: None.

Introduction

Among patients with intermediate coronary artery stenosis (50-90%), assessment of functional significance of the lesion by instantaneous wave free ratio (iFR)/ fractional flow reserve (FFR) is recommended in latest guidelines. Though iFR is not much affected by change in hemodynamics compared to FFR, the change in iFR vs FFR due to various hemodynamic factors need a validation. Left ventricular end-diastolic pressure (LVEDP) is one of the hemodynamic factors whose variation and effect on FFR vs iFR is largely unknown. In the present study we evaluated the association of change in LVEDP on the changing pattern of iFR/FFR which may hold a clinical significance especially with percutaneous coronary intervention in heart failure patients.

Methods

This was a prospective, investigator-initiated, single-center study involving 20 patients with stable coronary artery disease and at least one intermediate coronary lesion (50-90%). The enrolled patients were subjected to both iFR and FFR along with baseline LVEDP measurement. Subsequently, intravenous nitroglycerine infusion was given to reduce LVEDP and corresponding iFR and FFR were re-evaluated. The dynamic changes in iFR and FFR were studied in relation to changes in LVEDP using Pearson’s correlation analysis and linear regression analysis.

Results

The mean LVEDP was lowered from 16.20 ± 1.54 mmHg to 9.50 ± 1.10 mmHg, the mean iFR and FFR got changed from 0.80 ± 0.12 to 0.76 ± 0.12 mmHg and 0.75 ± 0.09 to 0.72 ± 0.09 mmHg respectively. On Pearson’s correlation analysis, LVEDP change did not show statistically significant correlation (linear relationship) with iFR (p = 0.105, r2 = 0.373) and FFR (p = 0.227, r2 = 0.283) changes across the entire range of stenosis severity and in all vessels. Linear regression analysis did not state any independent correlation between LVEDP and iFR and FFR changes in the study group (p >0.05). The % R2 value for iFR and FFR (as a coefficient of determination) of the regression equation were 13.9% and 8%, which means only these percentages of the total variance in iFR and FFR change were explained by LVEDP changes respectively. There was no serious adverse event related to the procedure.

Conclusion

To the best of our knowledge, this is the first study comparing the effect of changes in LVEDP on both iFR and FFR simultaneously. In our study, 1 mmHg change in LVEDP was associated with a change in FFR by 0.004 and change in iFR by 0.004 which didn’t reveal any significant association (p = 0.227 and 0.105 respectively). This helps us to put FFR at par with iFR under variable hemodynamics.  So either of the variables may be used interchangeably with confidence in varied hemodynamic conditions including patients with heart failure. The correlation was non-significant across entire range of stenosis severity, irrespective of sex, age, diabetes and hypertension. This study sets platform for further research with larger number of heterogeneous patient population. Abstract Figure. Box whisker plot

Role of oral flecainide in assessement of atrio-ventricular conduction in symptomatic bifascicular block

Background

Intravenous flecainide is used to stress Atrio-ventricular (AV) conduction in patients (pts) with a history of syncope & bifascicular (Bi-Fasc) block. Role of oral flecainide is unclear.

Objective

To assess effect of oral Flecainide on infra-Hisian AV conduction in patients with symptomatic Bi-Fasc block.

Methods

Pts presenting with syncope & Bi-Fasc block without advanced AVCD on ECG, 24 hr holter or treadmill exercise test were taken. Those with history suggestive of reflex syncope & positive tilt test were excluded. Remaining underwent electro-physiological (EP) study. Pts with HV interval >100ms or intra/infra-Hisian block at rest or incremental pacing were subjected to PPI. Remaining received oral Flacanide 5 mg/kg (max 300 mg) & EP study was repeated after ½ hr, 1 hr, 2 hrs and 3 hrs. Primary end-point was HV ≥100ms or infra/intra-Hisian type IIB or III block.

Results

Of 41 pts enrolled for study, 28 patients (mean age 60.0 yrs, mean LVEF 60.7%) were eligible for EP Study. Basal PR interval was 185.8±47.4 ms & mean QRS width was 130.6±18.65 ms. On EP study, 4 (14.3%) with resting HV >100 ms & 6 (21.4%) with HV >100 ms on incremental pacing underwent PPI.

Out of remaining 18 pts who were given flecainide, 11 (66.1%) achieved primary endpoint (HV >100 ms in 6, infra-hisian IIB in 2 and 2:1 block in 3 patients). At mean follow up of 6.5 months, 13 (59.1%) out of 22 with PPI had mean 59.1% VP & none of 6 remaining patients had any symptom.

Conclusion

Oral Flecainide significantly increases the diagnostic yield of EP study in patients with symptomatic bi-fasc block.

Funding Acknowledgement

Type of funding sources: None.

Comparison of traditional versus artificial intelligence based coronary artery disease risk prediction scores in young patients with acute coronary syndrome

Background

Ever since the concept of preventive cardiology has come into vogue, several risk identification models have come up which combine several risk factors to create a risk prediction score for occurrence of cardiovascular (CV) event. While carrying a proven validation in Western population, none of the risk prediction model has been satisfactorily evaluated in Indians especially young <40 years old.

Objectives

To compare Artificial Intelligence based novel risk score with traditional risk scores in young (less than 40 years age) patients presenting with acute coronary syndrome (ACS) and to estimate the relative efficacy of different coronary artery disease (CAD) risk scores in young Indian Patients.

Design

Single center, Observational, Non-interventional study.

Participants

Cohort of Patients more than 20 but less than 40 years old with ACS in the department of Cardiology from 1st January 2019 to 31st October 2019.

Methods

314 young patients [mean age 36.14±4.17 years] presenting with acute coronary syndrome (ACS) were enrolled. The three clinically most pertinent risk assessment models [Framingham Risk score (FRS), World Health Organization risk prediction charts (WHO/ISH), and QRISK3 scores] and Artificial Intelligence based novel risk score (AICVD) were applied on day 1 of presentation, and tried to see whether one risk score versus other risk score could have predicted the event earlier had we applied it before the occurrence of ACS. Risk factors considered included those already in traditional scoring systems and new risk factors (diet, alcohol, tobacco, dyslipidemia, physical activity, family history of heart disease, history of heart disease, heart rate, respiratory rate, chronic heart symptoms and psychological stress).

Results

WHO/ISH provided the lowest high risk estimate with only 1 (0.9%) patient estimated to be having >20% 10-year risk. The FRS estimated high risk (>20% 10-year risk) in 3 (1%) patients. The QRISK3 estimated high risk (>10% 10-year risk) in 20 (6.5%) patient. In comparison, AICVD risk prediction model stood tall by identifying 73 (23.2%) patients as high risk and 62.74% patients as more than moderate risk for having CV events at 7 years (p<0.001).

Conclusion

Perhaps, this is the first study which has compared artificial intelligence based novel risk prediction model with the three most commonly applied models, in the young Indian patients. We found that a cohort of young Indian patients presenting with ACS, when studied retrospectively, was identified as “high risk” most likely by AICVD risk prediction model rather than the traditional counterparts. The WHO/ISH risk prediction charts and FRS were the poorest predictors. Performance of QRISK3 score also remained less than satisfactory. These findings suggested that AICVD risk prediction model is a promising tool to assess for CV risk in Indian population.

Funding Acknowledgement

Type of funding sources: None. Predictability of risk prediction models

Non-exhaust traffic emissions: Sources, characterization, and mitigation measures

Non-exhaust emissions (NEE) of particulate matter (PM) from brake, tyre, road pavement and railway wear, as well as resuspension of already deposited road dust, account for up to 90% by mass of total traffic-related PM emitted. This review aims at analysing the current knowledge on road traffic NEE regarding sources, particle generation processes, chemical and physical characterization, and mitigation strategies. The literature on this matter often presents highly variable and hardly comparable results due to the heterogeneity of NEE sources and the absence of standardized sampling and measurement protocols. As evidence, emission factors (EFs) were found to range from 1 mg km^-1 veh^-1 to 18.5 mg km^-1 veh^-1 for brake wear, and from 0.3 mg km^-1 veh^-1 to 7.4 mg km^-1 veh^-1 for tyre wear. Resuspended dust, which varies in even wider ranges (from 5.4 mg km^-1 veh^-1 to 330 mg km^-1 veh^-1 for cars), is considered the prevailing NEE source. The lack of standardized monitoring approaches resulted in the impossibility of setting international regulations to limit NEE. Therefore, up until now the abatement of NEE has only been achieved by mitigation and prevention strategies. However, the effectiveness of these measures still needs to be improved and further investigated. As an example, mitigation strategies, such as street washing or sweeping, proved effective in reducing PM levels, but only in the short term. The replacement of internal combustion engines vehicles with electric ones was instead proposed as a prevention strategy, but there are still concerns regarding the increase of NEE deriving from the extra weight of the batteries. The data reported in this review highlighted the need for future studies to broaden their research area, and to focus not only on the standardization of methods and the introduction of regulations, but also on improving already existing technologies and mitigating strategies.

Field-scale demonstration of in situ immobilization of heavy metals by injecting iron oxide nanoparticle adsorption barriers in groundwater

Remediation of heavy metal-contaminated aquifers is a challenging process because they cannot be degraded by microorganisms. Together with the usually limited effectiveness of technologies applied today for treatment of heavy metal contaminated groundwater, this creates a need for new remediation technologies. We therefore developed a new treatment, in which permeable adsorption barriers are established in situ in aquifers by the injection of colloidal iron oxides. These adsorption barriers aim at the immobilization of heavy metals in aquifers groundwater, which was assessed in a large-scale field study in a brownfield site. Colloidal iron oxide (goethite) nanoparticles were used to install an in situ adsorption barrier in a very heterogeneous, contaminated aquifer of a brownfield in Asturias, Spain. The groundwater contained high concentrations of heavy metals with up to 25 mg/L zinc, 1.3 mg/L lead, 40 mg/L copper, 0.1 mg/L nickel and other minor heavy metal pollutants below 1 mg/L. High amounts of zinc (>900 mg/kg), lead (>2000 mg/kg), nickel (>190 mg/kg) were also present in the sediment. Ca. 1500 kg of goethite nanoparticles of 461 ± 266 nm diameter were injected at low pressure (< 0.6 bar) into the aquifer through nine screened injection wells. For each injection well, a radius of influence of at least 2.5 m was achieved within 8 h, creating an in situ barrier of 22 × 3 × 9 m. Despite the extremely high heavy metal contamination and the strong heterogeneity of the aquifer, successful immobilization of contaminants was observed in the tested area. The contaminant concentrations were strongly reduced immediately after the injection and the abatement of the heavy metals continued for a total post-injection monitoring period of 189 days. The iron oxide particles were found to adsorb heavy metals even at pH-values between 4 and 6, where low adsorption would have been expected. The study demonstrated the applicability of iron oxide nanoparticles for installing adsorption barriers for containment of heavy metals in contaminated groundwater under real conditions.

Electrokinetic Delivery of Reactants: Pore Water Chemistry Controls Transport, Mixing, and Degradation

Electrokinetics in porous media entails complex transport processes occurring upon the establishment of electric potential gradients, with a wide spectrum of environmental applications ranging from remediation of contaminated sites to biotechnology. The resulting electric forces cause the movement of pore water ions in opposite directions, leading to charge interactions that can affect the distribution of charged species in the domain. Here, we demonstrate that changes in chemical conditions, such as the concentration of a background electrolyte in the pore water of a saturated porous medium, exert a key control on the macroscopic transport of charged tracers and reactants. The difference in concentration between the background electrolyte and an injected solute can limit or enhance the reactant delivery, cause nonintuitive patterns of concentration distribution, and ultimately control mixing and degradation kinetics. With nonreactive and reactive electrokinetic transport experiments combined with process-based modeling, we show that microscopic charge interactions in the pore water play a crucial role on the transport of injected plumes and on the mechanisms and rate of both physical and chemical processes at larger, macroscopic scales. Our results have important implications on electrokinetic transport in porous media and may greatly impact injection and delivery strategies in a wide range of applications, including in situ remediation of soil and groundwater.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Secondary prevention of fragility fractures in Asia Pacific: an educational initiative

The Asia -Pacific Bone Academy (APBA) Fracture Liaison Service (FLS) Focus Group educational initiative has stimulated activity across the Asia -Pacific region with the intention of supporting widespread implementation of new FLS. In 2017, the APBA FLS Focus Group developed a suite of tools to support implementation of FLS across the Asia-Pacific region as a component of a multi-faceted educational initiative. This article puts this initiative into context with a narrative review describing the burden of fragility fractures in the region, the current secondary fracture prevention care gap and a summary of emerging best practice. The results of a survey to evaluate the impact of the APBA educational initiative is presented, in addition to commentary on recent activities intended to improve the care of individuals who sustain fragility fractures across the Asia -Pacific. A FLS Toolbox for Asia-Pacific was developed which included the following sections:1. The burden of fragility fractures in the Asia-Pacific region.2. A summary of evidence for FLS in the Asia-Pacific.3. A generic, fully referenced FLS business plan template.4. Potential cost savings accrued by each country, based on a country-specific FLS Benefits Calculator.5. How to start and expand FLS programmes in the Asia-Pacific context.6. A step-by-step guide to setting up FLS in countries in the Asia-Pacific region.7. Other practical tools to support FLS establishment.8. FLS online resources and publications.The FLS Toolbox was provided as a resource to support FLS workshops immediately following the 5th Scientific Meeting of the Asian Federation of Osteoporosis Societies (AFOS) held in Kuala Lumpur in October 2017. The FLS workshops addressed three key themes:• The FLS business case.• Planning the FLS patient pathway.• The role of the FLS coordinator in fragility fracture care management.A follow-up survey of 142 FLS workshop participants was conducted in August-September 2018. The survey included questions regarding how FLS were developed, funded, the scope of service provision and the support provided by the educational initiative. Almost one-third (30.3%) of FLS workshop participants completed the survey. Survey responses were reported for those who had established a FLS at the time the survey was conducted and, separately, for those who had not established a FLS. Findings for those who had established a FLS included:• 78.3% of respondents established a multidisciplinary team to develop the business case for their FLS.• 87.0% of respondents stated that a multidisciplinary team was established to design the patient pathway for their FLS.• 26.1% of respondents stated that their FLS has sustainable funding.• The primary source of funding for FLS was from public hospitals (83.3%) as compared with private hospitals (16.7%).Most hospitals that had not established a FLS at the time the survey was conducted were either in the process of setting-up a FLS (47%) or had plans in place to establish a FLS for which approval is being sought (29%). The primary barrier to establishing a new FLS was lack of sustainable funding. The APBA FLS Focus Group educational initiative has stimulated activity across the Asia-Pacific region with the intention of supporting widespread implementation of new FLS. A second edition of the FLS Toolbox is in development which is intended to complement ongoing efforts throughout the region to expedite widespread implementation of FLS.

Cardiovascular complications and its relationship with functional outcomes in Guillain-Barré syndrome

BACKGROUND

Guillain-Barré syndrome (GBS) is a monophasic disease characterized by acute polyradiculoneuropathy.

AIM

This study investigated cardiovascular complications in patients with GBS and their relationship with outcomes.

DESIGN AND METHODS

We included 96 patients, who were diagnosed with GBS according to Brighton case definitions. All enrolled patients were evaluated according to a predetermined algorithm, which included nerve conduction studies, cerebrospinal fluid analysis, electrocardiography, 2D echo, cardiac markers and autonomic function testing.

RESULTS

We enrolled a total of 96 patients. The mean age of patients was 35.75 ± 17.66 years. Furthermore, 54.2% of patients developed cardiovascular complications, of which changes in electrocardiography (ECG) findings (50%), hypertension (28.12%), labile hypertension (12.5), tachycardia (26.04), bradycardia (13.54%) and a fluctuating heart rate (HR) (11.46) were common. Other cardiovascular complications seen in GBS patients were increased pro-BNP (26.04%), raised troponin T levels (3.12%), acute coronary syndrome (2.08%), heart failure (2.08%) and abnormal 2D echo findings (8.33%). The results of the univariate analysis revealed that a history of preceding infection, a Medical Research Council sum score, neck muscle weakness, facial nerve involvement, bulbar involvement, respiratory failure, cardiovascular complications, autonomic dysfunction, acute motor sensory axonal neuropathy subtype and baseline Hughes score were significantly (P < 0.005) associated with poor outcomes. However, none of these factors were found to be independently associated with poor outcomes in the multivariate analysis.

CONCLUSION

A considerable number of patients with GBS developed cardiovascular complications and it needs attention.

Key factors affecting graphene oxide transport in saturated porous media

This study focuses on the transport in porous media of graphene oxide nanoparticles (GONP) under conditions similar to those applied in the generation of in-situ reactive zones for groundwater remediation (i.e. GO concentration of few tens of mg/l, stable suspension in alkaline solution). The experimental tests evaluated the influence on GO transport of three key factors, namely particle size (300-1200 nm), concentration (10-50 mg/L), and sand size (coarse to fine). Three sources of GONP were considered (two commercial and one synthesized in the laboratory). Particles were stably dispersed in water at pH 8.5 and showed a good mobility in the porous medium under all experimental conditions: after injection of 5 pore volumes and flushing, the highest recovery was around 90%, the lowest around 30% (only for largest particles in fine sand). The particle size was by far the most impacting parameter, with increasing mobility with decreasing size, even if sand size and particle concentration were also relevant. The source of GONP showed a minor impact on the mobility. The transport test data were successfully modeled using the advection-dispersion-deposition equations typically applied for spherical colloids. Experimental and modeling results suggested that GONP, under the explored conditions, are retained due to both blocking and straining, the latter being relevant only for large particles and/or fine sand. The findings of this study play a key role in the development of an in-situ groundwater remediation technology based on the injection of GONP for contaminant degradation or sorption. Despite their peculiar shape, GONP behavior in porous media is comparable with spherical colloids, which have been more studied by far. In particular, the possibility of modeling GONP transport using existing models ensures that they can be applied also for the design of field-scale injections of GONP, similarly to other particles already used in nanoremediation.

4300Strain parameters at rest and after exercise in symptomatically stable patients with improved heart failure - STRESS-HF

Background

Optimal medical therapy (OMT) results in improvement in left ventricular (LV) ejection fraction (EF) and reduction in LV size in approximately 40% of patients of heart failure with reduced ejection fraction (HFrEF). Recent studies have proposed to continue treatment in all patients of this subgroup as improvement in LVEF does not indicate actual myocardial recovery. Global Longitudinal strain (GLS) is more sensitive marker of LV systolic function and better predictor of mortality than LVEF. GLS may identify probable patients in whom the therapy can be minimized or stopped.

Aim

To determine global longitudinal strain at rest and after exercise in patients with idiopathic dilated cardiomyopathy (DCM) who have improved LVEF ≥50% on guideline directed medical therapy (GDMT) and compare with resting & exercising LVEF on 3-dimesional (3D).

Material and methods

This Observational study was conducted in a tertiary care referral hospital, from February 2018 to October 2018. All patients with idiopathic DCM who had a documented LVEF of ≤40% in the past and improved LVEF (LVEF ≥50%) on GDMT were included in the study. Patients with secondary causes of HFrEF, poor echocardiographic window and inability to exercise were excluded from the study. Strain parameters were calculated at rest and after atleast 5 METS of exercise. GLS value of ≥ minus 12.6% was considered as mildly reduced strain, ≤ minus 8% as severely reduced strain and the values in between as moderately reduced strain. Post exercise, drop of >5% in absolute LVEF value or decrease in GLS >15% from baseline was considered as poor myocardial recovery.

Results

A total of 44 patients [mean age of 46.8±13.1 years and 24 males (54.5%)] constituted the study group. At the time of diagnosis, 31 (70.5%) patients were in NYHA class II and the remaining were in class III. Duration of GDMT ranged from 4 to 38 (median 12) months. Following improvement on GDMT, 25 (56.8%) were in class I and rest were in class II. Mean LVEF at diagnosis and after recovery was 33.6±4.9% and 55.1±4.5%, respectively with a mean absolute change in LVEF of 21.3±6.1%. At rest, mean 3D LVEF was 53±3.5% and GLS was −12.3±3.1. Mild, moderate and severely reduced strain was seen in 24 (54.5%), 13 (29.6%) and 7 (15.9%), respectively. After exercise, mean 3D LVEF was 51.5.±4.5% (mean decrease 1.5±2.1%) and mean GLS was −7±4.2% (mean decrease −5.3±4.6%). After exercise, none had a fall of LVEF >5% however 32 (72.7%) had a decrease of >15% in GLS. Seven (15.9%) patients had improvement in GLS, 4 (9.1%) had <15% decrease and 1 (2.3%) showed no change in GLS on exercise. The change in GLS on exercise was significant (p=0.001), but change in 3D LVEF was not significant (p=0.956).

Conclusion

Global longitudinal strain is a better marker for assessing myocardial recovery than LVEF in patients of heart failure with improved ejection fraction.

Acknowledgement/Funding

None

Vive la Difference! The Effects of Natural and Conventional Wines on Blood Alcohol Concentrations: A Randomized, Triple-Blind, Controlled Study

Different alcoholic beverages can have different effects on blood alcohol concentration (BAC) and neurotoxicity, even when equalized for alcohol content by volume. Anecdotal evidence suggested that natural wine is metabolized differently from conventional wines. This triple-blind study compared the BAC of 55 healthy male subjects after consuming the equivalent of 2 units of alcohol of a natural or conventional wine over 3 min in two separate sessions, one week apart. BAC was measured using a professional breathalyzer every 20 min after consumption for 2 h. The BAC curves in response to the two wines diverged significantly at twenty minutes (interval T20) and forty minutes (interval T40), and also at their maximum concentrations (peaks), with the natural wine inducing a lower BAC than the conventional wine [T20 = 0.40 versus 0.46 (p < 0.0002); T40 = 0.49 versus 0.53 (p < 0.0015); peak = 0.52 versus 0.56 (p < 0.0002)]. These differences are likely related to the development of different amino acids and antioxidants in the two wines during their production. This may in turn affect the kinetics of alcohol absorption and metabolism. Other contributing factors could include pesticide residues, differences in dry extract content, and the use of indigenous or selected yeasts. The study shows that with the same quantity and conditions of intake, natural wine has lower pharmacokinetic and metabolic effects than conventional wine, which can be assumed due to the different agronomic and oenological practices with which they are produced. It can therefore be hypothesized that the consumption of natural wine may have a different impact on human health from that of conventional wine.

Coupling of Nanofiltration and Thermal Fenton Reaction for the Abatement of Carbamazepine in Wastewater

The complete removal of biorecalcitrant xenobiotics, including most notably the pharmaceutical pollutants, by advanced oxidation processes is often difficult to be reached in urban or industrial wastewater because of the high concentration of organic and inorganic scavengers that compete with the xenobiotics for the oxidizing species. This work investigates a coupled treatment train in which wastewater effluents are pretreated with a negatively charged loose nanofiltration (NF) membrane (HydraCoRe70, made up of sulfonated polyethersulfone) to enhance the removal of xenobiotics with the thermal Fenton process. Carbamazepine (CBZ), a drug prescribed mainly for epilepsy treatment, is used here as a model xenobiotic. After optimizing the conditions for separation and degradation, the NF-Fenton approach was applied to both synthetic wastewater and real samples to assess the overall efficiency of CBZ removal. The Fenton degradation of CBZ was drastically enhanced in nanofiltered samples, thanks to the removal by the membrane of nearly all organic matter that would otherwise consume the reactive oxidizing species (e.g., the hydroxyl radical). On the basis of a preliminary treatment cost analysis, it can be concluded that the combined process is potentially applicable to the treatment of several kinds of wastewaters (e.g., industrial ones) to favor the removal of biorecalcitrant contaminants. Key cost savings of NF-Fenton concern the lower amounts of Fenton reagents needed to degrade CBZ and (even more importantly) the decreased levels of acids and bases for pH adjustment before and after the oxidative process because of the lower buffer capacity of the NF permeate compared to feed wastewater, after the removal by the NF of many inorganic ions and most organic carbon.

Human health risk assessment for nanoparticle-contaminated aquifer systems

Nanosized particles (NPs), such as TiO₂, Silver, graphene NPs, nanoscale zero-valent iron, carbon nanotubes, etc., are increasingly used in industrial processes, and releases at production plants and from landfills are likely scenarios for the next years. As a consequence, appropriate procedures and tools to quantify the risks for human health associated to these releases are needed. The tiered approach of the standard ASTM procedure (ASTM-E2081-00) is today the most applied for human health risk assessment at sites contaminated by chemical substances, but it cannot be directly applied to nanoparticles: NP transport along migration pathways follows mechanisms significantly different from those of chemicals; moreover, also toxicity indicators (namely, reference dose and slope factor) are NP-specific. In this work a risk assessment approach modified for NPs is proposed, with a specific application at Tier 2 to migration in groundwater. The standard ASTM equations are modified to include NP-specific transport mechanisms. NPs in natural environments are typically characterized by a heterogeneous set of NPs having different size, shape, coating, etc. (all properties having a significant impact on both mobility and toxicity). To take into account this heterogeneity, the proposed approach divides the NP population into classes, each having specific transport and toxicity properties, and simulates them as independent species. The approach is finally applied to a test case simulating the release of heterogeneous Silver NPs from a landfill. The results show that taking into account the size-dependent mobility of the particles provides a more accurate result compared to the direct application of the standard ASTM procedure. In particular, the latter tends to underestimate the overall toxic risk associated to the nP release.

Ecofriendly nanotechnologies and nanomaterials for environmental applications: Key issue and consensus recommendations for sustainable and ecosafe nanoremediation

The use of engineered nanomaterials (ENMs) for environmental remediation, known as nanoremediation, represents a challenging and innovative solution, ensuring a quick and efficient removal of pollutants from contaminated sites. Although the growing interest in nanotechnological solutions for pollution remediation, with significant economic investment worldwide, environmental and human risk assessment associated with the use of ENMs is still a matter of debate and nanoremediation is seen yet as an emerging technology. Innovative nanotechnologies applied to water and soil remediation suffer for a proper environmental impact scenario which is limiting the development of specific regulatory measures and the exploitation at European level. The present paper summarizes the findings from the workshop: "Ecofriendly Nanotechnology: state of the art, future perspectives and ecotoxicological evaluation of nanoremediation applied to contaminated sediments and soils" convened during the Biannual ECOtoxicology Meeting 2016 (BECOME) held in Livorno (Italy). Several topics have been discussed and, starting from current state of the art of nanoremediation, which represents a breakthrough in pollution control, the following recommendations have been proposed: (i) ecosafety has to be a priority feature of ENMs intended for nanoremediation; ii) predictive safety assessment of ENMs for environmental remediation is mandatory; (iii) greener, sustainable and innovative nano-structured materials should be further supported; (iii) those ENMs that meet the highest standards of environmental safety will support industrial competitiveness, innovation and sustainability. The workshop aims to favour environmental safety and industrial competitiveness by providing tools and modus operandi for the valorization of public and private investments.

A robust upscaling of the effective particle deposition rate in porous media

In the upscaling from pore to continuum (Darcy) scale, reaction and deposition phenomena at the solid-liquid interface of a porous medium have to be represented by macroscopic reaction source terms. The effective rates can be computed, in the case of periodic media, from three-dimensional microscopic simulations of the periodic cell. Several computational and semi-analytical models have been studied in the field of colloid filtration to describe this problem. They typically rely on effective deposition rates defined by complex fitting procedures, neglecting the advection-diffusion interplay, the pore-scale flow complexity, and assuming slow reactions (or large Péclet numbers). Therefore, when these rates are inserted into general macroscopic transport equations, they can lead to several conceptual inconsistencies and significant errors. To study more accurately the dependence of deposition on the flow parameters, in this work we advocate a clear distinction between the surface processes (that altogether defines the so-called attachment efficiency), and the pore-scale processes. With this approach, valid when colloidal particles are small enough, we study Brownian and gravity-driven deposition on a face-centred cubic (FCC) arrangement of spherical grains, and define a robust upscaling based on a linear effective reaction rate. The case of partial deposition, defined by an attachment probability, is studied and the limit of perfect sink is retrieved as a particular case. We introduce a novel upscaling approach and a particularly convenient computational setup that allows the direct computation of the asymptotic stationary value of effective rates. This allows to drastically reduce the computational domain down to the scale of the single repeating periodic unit. The savings are ever more noticeable in the case of higher Péclet numbers, when larger physical times are needed to reach the asymptotic regime and thus, equivalently, much larger computational domain and simulation time would be needed in a traditional setup. We show how this new definition of deposition rate is more robust and extendable to the whole range of Péclet numbers; it also is consistent with the classical heat and mass transfer literature.

Management protocols for chronic heart failure in India

Heart failure is a common clinical syndrome and a global health priority. The burden of heart failure is increasing at an alarming rate worldwide as well as in India. Heart failure not only increases the risk of mortality, morbidity and worsens the patient's quality of life, but also puts a huge burden on the overall healthcare system. The management of heart failure has evolved over the years with the advent of new drugs and devices. This document has been developed with an objective to provide standard management guidance and simple heart failure algorithms to aid Indian clinicians in their daily practice. It would also inform the clinicians on the latest evidence in heart failure and provide guidance to recognize and diagnose chronic heart failure early and optimize management.

Under-utilization of pacemaker therapy for sinus node dysfunction - Real world data from South Asia

OBJECTIVE

Chronic symptomatic sinus node dysfunction (SND), the most common bradyarrhythmia, can be effectively managed by permanent cardiac pacing. Yet the care pathway and barriers to adoption of pacing therapy are not well understood - particularly in low volume implanting countries. The IMPROVE Brady study is a quality improvement initiative being conducted at centers in South Asia, Latin America, and Russia. We assessed the rates of SND diagnosis and pacemaker treatment for SND in the South Asia cohort.

METHODS

The prospective study enrolled patients with heart rate of  ≤50 beats per minute presenting with symptoms including syncope, dizziness, and/or dyspnea from ten centers in India and Bangladesh. Patients were followed to identify the proportion diagnosed with SND and subsequently treated with pacemaker therapy.

RESULTS

A total of 508 patients meeting criteria were enrolled and followed on average for 8.3±8.0months. Patients were on average 58 years of age, 77% were male, and 91% had completed at least primary education. An SND diagnosis was made in 368 (72%) of patients, with the majority (80%) of diagnoses occurring within 1 month of enrollment. Of the patients with an SND diagnosis, 63 (17%) were treated with a pacemaker. Reasons for not receiving treatment were: subject refusal or deferred decision (45%), unaffordability (34%), physician determined - not-indicated (20%), and other (1%). Older age, female gender, history of hypertension, lower resting heart rate, and syncopal or pre-syncopal symptoms were associated with a higher probability of implant.

CONCLUSIONS

In a care pathway assessment for the diagnosis and treatment of symptomatic SND in South Asia only 1 in 6 patients received pacemaker indicated therapy, largely due to patient refusal and physician decision. Phase II of the study will be aimed to improve this treatment rate.

Recirculation zones induce non-Fickian transport in three-dimensional periodic porous media

In this work, the influence of pore space geometry on solute transport in porous media is investigated performing computational fluid dynamics pore-scale simulations of fluid flow and solute transport. The three-dimensional periodic domains are obtained from three different pore structure configurations, namely, face-centered-cubic (fcc), body-centered-cubic (bcc), and sphere-in-cube (sic) arrangements of spherical grains. Although transport simulations are performed with media having the same grain size and the same porosity (in fcc and bcc configurations), the resulting breakthrough curves present noteworthy differences, such as enhanced tailing. The cause of such differences is ascribed to the presence of recirculation zones, even at low Reynolds numbers. Various methods to readily identify recirculation zones and quantify their magnitude using pore-scale data are proposed. The information gained from this analysis is then used to define macroscale models able to provide an appropriate description of the observed anomalous transport. A mass transfer model is applied to estimate relevant macroscale parameters (hydrodynamic dispersion above all) and their spatial variation in the medium; a functional relation describing the spatial variation of such macroscale parameters is then proposed.

A 3-dimensional micro- and nanoparticle transport and filtration model (MNM3D) applied to the migration of carbon-based nanomaterials in porous media

Engineered nanoparticles (NPs) in the environment can act both as contaminants, when they are unintentionally released, and as remediation agents when injected on purpose at contaminated sites. In this work two carbon-based NPs are considered, namely CARBO-IRON®, a new material developed for contaminated site remediation, and single layer graphene oxide (SLGO), a potential contaminant of the next future. Understanding and modeling the transport and deposition of such NPs in aquifer systems is a key aspect in both cases, and numerical models capable to simulate NP transport in groundwater in complex 3D scenarios are necessary. To this aim, this work proposes a modeling approach based on modified advection-dispersion-deposition equations accounting for the coupled influence of flow velocity and ionic strength on particle transport. A new modeling tool (MNM3D - Micro and Nanoparticle transport Model in 3D geometries) is presented for the simulation of NPs injection and transport in 3D scenarios. MNM3D is the result of the integration of the numerical code MNMs (Micro and Nanoparticle transport, filtration and clogging Model - Suite) in the well-known transport model RT3D (Clement et al., 1998). The injection in field-like conditions of CARBO-IRON® (20g/l) amended by CMC (4g/l) in a 2D vertical tank (0.7×1.0×0.12m) was simulated using MNM3D, and compared to experimental results under the same conditions. Column transport tests of SLGO at a concentration (10mg/l) representative of a possible spill of SLGO-containing waste water were performed at different values of ionic strength (0.1 to 35mM), evidencing a strong dependence of SLGO transport on IS, and a reversible blocking deposition. The experimental data were fitted using the numerical code MNMs and the ionic strength-dependent transport was up-scaled for a full scale 3D simulation of SLGO release and long-term transport in a heterogeneous aquifer. MNM3D showed to potentially represent a valid tool for the prediction of the long-term behavior of engineered nanoparticles released in the environment (e.g. from landfills), and the preliminary design of in situ aquifer remediation through injection of suspensions of reactive NPs.

Pressure-controlled injection of guar gum stabilized microscale zerovalent iron for groundwater remediation

The paper reports a pilot injection test of microsized zerovalent iron (mZVI) dispersed in a guar gum shear thinning solution. The test was performed in the framework of the EU research project AQUAREHAB in a site in Belgium contaminated by chlorinated aliphatic hydrocarbons (CAHs). The field application was aimed to overcome those critical aspects which hinder mZVI field injection, mainly due to the colloidal instability of ZVI-based suspensions. The iron slurry properties (iron particles size and concentration, polymeric stabilizer type and concentration, slurry viscosity) were designed in the laboratory based on several tests (reactivity tests towards contaminants, sedimentation tests and rheological measurements). The particles were delivered into the aquifer through an injection well specifically designed for controlled-pressure delivery (approximately 10 bars). The well characteristics and the critical pressure of the aquifer (i.e. the injection pressure above which fracturing occurs) were assessed via two innovative injection step rate tests, one performed with water and the other one with guar gum. Based on laboratory and field preliminary tests, a flow regime at the threshold between permeation and preferential flow was selected for mZVI delivery, as a compromise between the desired homogeneous distribution of the mZVI around the injection point (ensured by permeation flow) and the fast and effective injection of the slurry (guaranteed by high discharge rates and injection pressure, resulting in the generation of preferential flow paths). A monitoring setup was designed and installed for the real-time monitoring of relevant parameters during injection, and for a fast determination of the spatial mZVI distribution after injection via non-invasive magnetic susceptibility measurements.

Monitoring the injection of microscale zerovalent iron particles for groundwater remediation by means of complex electrical conductivity imaging

The injection of microscale zerovalent iron (mZVI) particles for groundwater remediation has received much interest in recent years. However, to date, monitoring of mZVI particle injection is based on chemical analysis of groundwater and soil samples and thus might be limited in its spatiotemporal resolution. To overcome this deficiency, in this study, we investigate the application of complex electrical conductivity imaging, a geophysical method, to monitor the high-pressure injection of mZVI in a field-scale application. The resulting electrical images revealed an increase in the induced electrical polarization (∼20%), upon delivery of ZVI into the targeted area, due to the accumulation of metallic surfaces at which the polarization takes place. Furthermore, larger changes (>50%) occurred in shallow sediments, a few meters away from the injection, suggesting the migration of particles through preferential flowpaths. Correlation of the electrical response and geochemical data, in particular the analysis of recovered cores from drilling after the injection, confirmed the migration of particles (and stabilizing solution) to shallow areas through fractures formed during the injection. Hence, our results demonstrate the suitability of the complex conductivity imaging method to monitor the transport of mZVI during subsurface amendment in quasi real-time.