Quantification Of Fraction Research Articles

Quantification of left ventricular ejection fraction and cardiac output using a novel semi-automated echocardiographic method: a prospective observational study in coronary artery bypass patients

BackgroundEchocardiographic quantification of ejection fraction (EF) by manual endocardial tracing requires training, is time-consuming and potentially user-dependent, whereas determination of cardiac output by pulmonary artery catheterization (PAC) is invasive and carries a risk of complications. Recently, a novel software for semi-automated EF and CO assessment (AutoEF) using transthoracic echocardiography (TTE) has been introduced. We hypothesized that AutoEF would provide EF values different from those obtained by the modified Simpson’s method in transoesophageal echocardiography (TOE) and that AutoEF CO measurements would not agree with those obtained via VTILVOT in TOE and by thermodilution using PAC.MethodsIn 167 patients undergoing coronary artery bypass graft surgery (CABG), TTE cine loops of apical 4- and 2-chamber views were recorded after anaesthesia induction under steady-state conditions. Subsequently, TOE was performed following a standardized protocol, and CO was determined by thermodilution. EF and CO were assessed by TTE AutoEF as well as TOE, using the modified Simpson’s method, and Doppler measurements via velocity time integral in the LV outflow tract (VTILVOT). We determined Pearson’s correlation coefficients r and carried out Bland–Altman analyses. The primary endpoints were differences in EF and CO. The secondary endpoints were differences in left ventricular volumes at end diastole (LVEDV) and end systole (LVESV).ResultsAutoEF and the modified Simpson’s method in TOE showed moderate EF correlation (r = 0.38, p < 0.01) with a bias of -12.6% (95% limits of agreement (95%LOA): -36.6 – 11.3%). AutoEF CO correlated poorly both with VTILVOT in TOE (r = 0.19, p < 0.01) and thermodilution (r = 0.28, p < 0.01). The CO bias between AutoEF and VTILVOT was 1.33 l min−1 (95%LOA: -1.72 – 4.38 l min−1) and 1.39 l min−1 (95%LOA -1.34 – 4.12 l min−1) between AutoEF and thermodilution, respectively. AutoEF yielded both significantly lower EF (EFAutoEF: 42.0% (IQR 29.0 — 55.0%) vs. EFTOE Simpson: 55.2% (IQR 40.1 — 70.3%), p < 0.01) and CO values than the reference methods (COAutoEF biplane: 2.30 l min−1 (IQR 1.30 - 3.30 l min−1) vs. COVTI LVOT: 3.64 l min−1 (IQR 2.05 - 5.23 l min−1) and COPAC: 3.90 l min−1 (IQR 2.30 - 5.50 l min−1), p < 0.01)).ConclusionsAutoEF correlated moderately with TOE EF determined by the modified Simpson’s method but poorly both with VTILVOT and thermodilution CO. A systematic bias was detected overestimating LV volumes and underestimating both EF and CO compared to the reference methods.Trial registrationGerman Register for Clinical Trials (DRKS-ID DRKS00010666, date of registration: 08/07/2016).

Bone marrow cellularity assessment using magnetic resonance imaging in children with aplastic anemia

Aplastic anemia is a life-threatening condition characterized by the suppression of all hematopoietic lineages in the bone marrow. Empty intertrabecular spaces are replaced by adipose tissue. With modern MR techniques for assessing fat fraction, it has become possible to capture these changes. The fat fraction is estimated as the ratio of the signal intensity from fat to the sum of the fat and water signals. Aim of the study: to assess the diagnostic value of bone marrow fat fraction quantification in patients aged &lt; 18 years with aplastic anemia. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of the Ministry of Healthcare of the Russian Federation. The study included 66 participants aged under 18 years. A control group consisted of 33 healthy subjects with a mean age of 13.03 ± 2.83 years. A group of interest included 33 children with a confirmed diagnosis of aplastic anemia, with a mean age of 12.31 ± 4.39 years. The study was carried out at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of the Ministry of Healthcare of the Russian Federation; all scanning was performed on a Philips Achieva 3.0T MRI scanner using the mDixon-quant sequence in the iliac bones and lumbar vertebrae. Our results showed that bone marrow fat fraction was significantly higher in the aplastic anemia group than in the controls. In the patients with aplastic anemia, the mean fat fraction values in the iliac bones and in the L4, L5 vertebrae were 82.62 ± 10.92% and 73.52 ± 17.52%, respectively. In the control group, the mean fat fraction values for these sites were 51.04 ± 11.41% and 31.43 ± 10.61%, respectively. We found a significant difference in fat fraction values for the same sites between the groups (p &lt; 0.01). Bone marrow fat fraction quantification by MRI allows for the detection of decreased cellularity of the marrow in patients under 18 years of age with aplastic anemia compared to healthy children.

Rationalizing the interfacial layer in polymer nanocomposites: Correlation between enthalpy and dielectric relaxation

The accurate and convenient characterization of the interfacial layer is a crucial prerequisite for understanding the relationship between structure and macroscopic properties in polymer nanocomposites (PNCs). Herein, enthalpy relaxation and interfacial layer properties estimated from temperature-modulated differential scanning calorimetry (TMDSC) and broadband dielectric spectroscopy (BDS) of model PNCs with attractive interactions are investigated. We demonstrate that enthalpy relaxation enables the accurate quantification of the volume fraction of the interfacial layer (φint) as TMDSC and BDS. The parameter (χint) corresponding to the decreased degree of enthalpy hysteresis (ΔHR) related to the contribution of the interfacial layer, is identical with φint estimated from BDS, while presents only similar dependence on nanoparticle loading with φint estimated from TMDSC. This interesting phenomenon can be ascribed to the consistency between enthalpy and dielectric relaxation, which both characterize the dynamic change of polymer mainly originating from segmental relaxation. Such an unexpected correlation between enthalpy and dielectric relaxation provides a new approach to characterize the interfacial layer properties of PNCs and understand its impact on the glass transition behavior.

Liver fat quantification in photon counting CT in head to head comparison with clinical MRI – First experience

PurposeTo compare liver fat quantification between MRI and photon-counting CT (PCCT). MethodA cylindrical phantom with inserts containing six concentrations of oil (0, 10, 20, 30, 50 and 100%) and oil-iodine mixtures (0, 10, 20, 30 and 50% fat +3 mg/mL iodine) was imaged with a PCCT (NAEOTOM Alpha) and a 1.5 T MRI system (MR 450w, IDEAL-IQ sequence), using clinical parameters. An IRB-approved prospective clinical evaluation included 12 obese adult patients with known fatty liver disease (seven women, mean age: 61.5 ± 13 years, mean BMI: 30.3 ± 4.7 kg/m2). Patients underwent a same-day clinical MRI and PCCT of the abdomen. Liver fat fractions were calculated for four segments (I, II, IVa and VII) using in- and opposed-phase on MRI ((Meanin – Meanopp)/2*Meanin) and iodine-fat, tissue decomposition analysis in PCCT (Syngo.Via VB60A). CT and MRI Fat fractions were compared using two-sample t-tests with equal variance. Statistical analysis was performed using RStudio (Version1.4.1717). ResultsPhantom results showed no significant differences between the known fat fractions (P = 0.32) or iodine (P = 0.6) in comparison to PCCT-measured concentrations, and no statistically significant difference between known and MRI-measured fat fractions (P = 0.363). In patients, the mean fat signal fraction measured on MRI and PCCT was 13.1 ± 9.9% and 12.0 ± 9.0%, respectively, with an average difference of 1.1 ± 1.9% between the modalities (P = 0.138). ConclusionFirst experience shows promising accuracy of liver fat fraction quantification for PCCT in obese patients. This method may improve opportunistic screening for CT in the future.

Deep learning-based automatic pipeline for quantitative assessment of thigh muscle morphology and fatty infiltration.

Fast and accurate thigh muscle segmentation from MRI is important for quantitative assessment of thigh muscle morphology and composition. A novel deep learning (DL) based thigh muscle and surrounding tissues segmentation model was developed for fully automatic and reproducible cross-sectional area (CSA) and fat fraction (FF) quantification and tested in patients at 10 years after anterior cruciate ligament reconstructions. A DL model combining UNet and DenseNet was trained and tested using manually segmented thighs from 16 patients (32 legs). Segmentation accuracy was evaluated using Dice similarity coefficients (DSC) and average symmetric surface distance (ASSD). A UNet model was trained for comparison. These segmentations were used to obtain CSA and FF quantification. Reproducibility of CSA and FF quantification was tested with scan and rescan of six healthy subjects. The proposed UNet and DenseNet had high agreement with manual segmentation (DSC >0.97, ASSD < 0.24) and improved performance compared with UNet. For hamstrings of the operated knee, the automated pipeline had largest absolute difference of 6.01% for CSA and 0.47% for FF as compared to manual segmentation. In reproducibility analysis, the average difference (absolute) in CSA quantification between scan and rescan was better for the automatic method as compared with manual segmentation (2.27% vs. 3.34%), whereas the average difference (absolute) in FF quantification were similar. The proposed method exhibits excellent accuracy and reproducibility in CSA and FF quantification compared with manual segmentation and can be used in large-scale patient studies.

Studies on the Impact of Selected Pretreatments on Protein Solubility of Arthrospira platensis Microalga

Arthrospira platensis has emerged as a novel protein feed source since it contains high protein level and quality. However, this microalga presents a recalcitrant cell wall and its main proteins form protein-pigment complexes attached to the thylakoid membrane. The objective of the present study was to evaluate the influence of mechanical/physical pretreatments (bead milling, extrusion, freeze-drying, heating, microwave and sonication) on A. platensis protein solubility. Total protein content and solubility were assessed by Bradford method and SDS-PAGE quantification. Protein degradation was assessed through quantification of protein fractions (18–26 kDa, 40–48 kDa and others) in SDS-PAGE gels. Peptide formation was evaluated using the o-phthaldialdehyde assay. The results showed a decrease in total protein content in the supernatant with extrusion (0.07 to 1.42 mg/mL) and microwave pretreatments, and in the pellet with extrusion. Therefore, extrusion, followed by microwave, was the most effective pretreatment for A. platensis proteins denaturation and solubility. It is suggested that the extrusion process cause an irreversible denaturation and aggregation of the major microalga proteins (c-phycocyanin and allophycocyanin), with a strong decrease in their solubility. Therefore, extrusion could increase the bioaccessibility of A. platensis proteins and enable the incorporation of this microalga at higher levels in monogastric diets.

Combination of Mechanical/Physical Pretreatments with Trypsin or Pancreatin on Arthrospira platensis Protein Degradation

Arthrospira platensis contains high protein content and quality, which makes it a promising feed source for livestock animals. However, this microalga presents a recalcitrant peptidoglycan cell wall, and its main proteins form protein-pigment complexes attached to the algal thylakoid membrane. The purpose of the present study was to evaluate the effect of mechanical/physical pretreatments (bead milling, extrusion, freeze-drying, heating, microwave and sonication) combined with commercial enzymes (trypsin or pancreatin) on the degradation of A. platensis proteins. Protein degradation was assessed through the quantification of total protein and protein fractions (18–26 kDa, 40–48 kDa and others) on SDS-PAGE gels and the evaluation of the coefficient of protein degradation (CPD). The results showed that no significant differences were found among treatments for CPD values, except for an increase related to 18–26 kDa protein (phycocyanin subunits) with extrusion combined with pancreatin. In addition, extrusion and microwave caused a decrease of total protein in algal supernatant probably due to a denaturation/aggregation and reduction of solubility. Overall, extrusion is a promising pretreatment for A. platensis cell wall disruption and protein bioaccessibility. Further studies could elucidate how the effect of extrusion on protein solubility affects the activity of peptidases on protein degradation.

Quantification of shunt fraction using contrast ultrasound and indicator dilution in an in vitro model

Transthoracic saline contrast echocardiography is commonly used to assess intrathoracic shunt flow in vivo. Though the technique has many advantages (safe, simple, repeatable), the measurement technique lacks specificity, and the contrast agent has limited stability. This study sought to determine if the indicator dilution modeling technique could be applied to ultrasound contrast data to quantify shunt fraction and to determine if buoyant force has a significant effect on microbubble pathway determination at a “vascular” bifurcation. A model of the pulmonary circuit was perfused with blood at three distinct flow rates (low, medium and high) over shunt fractions ranging from ∼2–10 %. The buoyancy effect on contrast was quantified using a simplified in vitro model of a vascular bifurcation that had an upper and lower outflow tract where saline contrast formed from carbon monoxide (CO) gas passed through the bifurcation, was collected and quantified. The indicator dilution model was found to have a mean bias of − 3.2 % for the low flow stage, − 2.6 % for the medium flow stage and − 1.4 % for the high flow stage compared to volumetric measurements, suggesting agreement increases with increasing flow rate. Investigations of the buoyant effects revealed that at lower flow rates, contrast bubbles that encounter a bifurcation will favor the upper outflow tract over the lower. However, this effect is reduced by increasing the flow rate two-fold. These data identify that application of indicator dilution theory to contrast ultrasound data and the pathway ultrasound contrast travels in a network of tubules is flow dependent.

Reporter emission multiplexing in digital PCRs (REM-dPCRs): direct quantification of multiple target sequences per detection channel by population specific reporters.

Digital PCRs (dPCRs) are widely used methods for the detection and quantification of rare abundant sequences relevant to fields such as liquid biopsy or oncology. In order to increase the information content and save valuable sample materials, there is a significant need for digital multiplexing methods that are easy to establish, analyse, and interpret, and ideally allow the usage of existing lab equipment. Herein, we present a novel reporter emission multiplexing approach for the digital PCR method (REM-dPCR), which meets these requirements. It further increases the multiplexing capacity of commercial dPCR devices. For example, we present a stepwise increase in multiplexing degrees from a monochrome two-plex assay in one detection channel to a six-plex REM-dPCR assay in a three-color dPCR device for KRAS/BRAF single nucleotide polymorphism (SNP) target sequences. The guidelines for the REM-dPCR design are presented, and the process from duplex to six-plex assay establishment, taking into account the target sequence-dependent effects on assay performance, is discussed. Furthermore, the assay-specific, sensitive and precise quantification of different fractions of KRAS mutant and wild-type DNA sequences in different ratios is demonstrated. To increase the device capacitance and the degree of multiplexing, the REM-dPCR uses the advantage of n target-independent reporter molecules in combination with target sequence-specific mediator probes. Different reporter types are labelled with fluorophores of different signal intensities but not necessarily different emission spectra. This leads to the generation of n independent single-positive populations in the dataspace, created by k detection channels, whereby n > k and n ≥ 2. By usage of target-independent but population-specific reporter types, a fixed set of six optimized signalling molecules could be defined. This reporter set enables the robust generation and precise differentiation of multiple fluorescence signals in dPCRs and can be transferred to new target panels. The set which enables stable signal generation and differentiation in a specified device would allow easy transfer to new target panels.

Role of cardiac magnetic resonance imaging in the diagnosis of nonischemic cardiomyopathies

In recent decades, cardiac magnetic resonance imaging (CMR) has been established &amp;nbsp;as a valuable tool in the diagnosis of patients with or at risk of heart failure. With its ability to characterize tissue changes in the myocardium, CMR can provide detailed and clinically useful information about the type and severity of cardiac damage. The method is not only important for differentiation of ischemic from non-ischemic cardiomyopathy, but also contributes to the correct diagnosis of non-ischemic cardiomyopathy subtypes. It is also widely accepted as a reference standard for the quantification of myocardial mass, volumes and ejection fraction. The purpose of this article is to review the role of CMR in the diagnosis and treatment of non-ischemic cardiomyopathies.

Hocus POCUS! Parental Quantification of Left-Ventricular Ejection Fraction Using Point of Care Ultrasound: Fiction or Reality?

Point of care ultrasound has become increasingly utilized in pediatric settings. The assessment of cardiac function is one such implementation of this. This study aimed to determine the feasibility of parents in acquiring images to assess function using a handheld ultrasound probe and the correlation of fractional shortening measurements by handheld ultrasound with hospital acquired echocardiography. This was a single-center prospective study of parents of pediatric patients admitted to the hospital. Parents underwent a 25-min education session on how to use the handheld ultrasound probe and then were asked to acquire a parasternal short-axis and apical four-chamber image on their own. Acquired images were reviewed by two physicians to determine adequacy of images to assess systolic cardiac function subjectively and objectively. Fractional shortening was measured using parent-acquired images and then compared to recent hospital acquired fractional shortening. A total of 25 parents of 21 patients enrolled and completed the study. Of the enrolled parents, 96% of both parasternal short-axis and apical four-chamber images acquired were deemed appropriate for subjective assessment of systolic function. Inter-reader variability of fractional shortening was moderate between two readers. Correlation of fractional shortening measured from parent-acquired images versus hospital acquired images was moderate. Parents were able to successfully obtain a parasternal short-axis and apical four-chamber image adequate to assess function and quantify fractional shortening after a 25-min education session. This pilot data demonstrate that further exploration of parent-performed point of care cardiac assessment may be warranted.

Quantitative assessment of machine-learning segmentation of battery electrode materials for active material quantification

X-ray computed tomography (CT) is an important tool for studying battery electrode microstructures but relies on robust segmentation for validity. Here, several approaches to applying accessible machine-learning segmentation software to segment open-source lithium-ion battery (LIB) electrode tomograms are followed to identify the optimised methodology that minimises variation in active material volume fraction quantification across three users. Iterative, manual training across seven cross-sectional slices (<5%) of a tomogram is identified as an optimal balance between variance and user interaction, where 10–25% of each slice was trained. This approach is applied to lab-based X-ray CT data and compared with data obtained by focused-ion beam/scanning electron microscopy slice-and-view tomography. Variation in active material volume fraction between users is lower for at least one of these two approaches (10% or 25%) when applied to raw LIB cathode tomograms, versus unsupervised techniques such as simple and watershed segmentations. On average, the absolute volume fraction values are closer to that acquired by the correlated technique, most closely matching for high-resolution data. The present analysis provides an optimised approach for using open-source software to apply machine-learning segmentation when quantifying active material volume fractions in cutting-edge LIB electrodes, providing a more robust route to active material quantification.

Free Fatty Acids from Type 2 Diabetes Mellitus Serum Remodel Mesenchymal Stem Cell Lipids, Hindering Differentiation into Primordial Germ Cells.

Type 2 diabetes mellitus (T2DM) adversely affects the essential characteristics of adipose tissue-derived mesenchymal stem cells (AdMSCs). Given that T2DM is associated with an altered serum free fatty acid (FFA) profile, we examined whether diabetic serum FFAs influence the viability, differentiation, and fatty acid composition of the major lipid fractions of human AdMSCs in vitro. Serum FFAs were isolated from 7 diabetic and 10 healthy nondiabetic female individuals. AdMSCs were cultured and differentiated into primordial germ cell-like cells (PGCLCs) in the presence of either diabetic or nondiabetic FFAs. Cell viability was assessed using trypan blue staining. Cell differentiation was evaluated by measuring the PGCLC transcriptional markers Blimp1 and Stella. Lipid fractionation and fatty acid quantification were performed using thin-layer chromatography and gas-liquid chromatography, respectively. Both diabetic and nondiabetic FFAs significantly reduced the viability of PGCLCs. The gene expression of both differentiation markers was significantly lower in cells exposed to diabetic FFAs than in those treated with nondiabetic FFAs. Saturated fatty acids were significantly increased and linoleic acid was significantly decreased in the cellular phospholipid fraction after exposure to diabetic FFAs. In contrast, monounsaturated fatty acids were reduced and linoleic acid was elevated in the cellular triglyceride fraction in response to diabetic FFAs. Such an altered serum FFA profile in patients with T2DM reduces the proliferation and differentiation potential of AdMSCs, presumably due to the aberrant distribution of fatty acids into cell phospholipids and triglycerides.

Analysis of hierarchical microstructural evolution in electron beam powder bed fusion Ti–6Al–4V alloys via time-of-flight neutron diffraction

Ti–6Al–4V alloys prepared via electron beam powder bed fusion (EB-PBF) generally exhibit a hierarchical microstructure consisting of columnar β-grains, an acicular α-matrix, and nanoscale β-precipitates at α-lath interfaces. In this study, we performed time-of-flight neutron diffraction measurements to investigate the texture and volume fraction of EB-PBF Ti–6Al–4V alloys via Rietveld texture analysis (RTA). The high-intensity neutron source enabled the analysis of the nanosized β-phase precipitates at the α-lath interfaces. The results indicate that the α- and β-textures of the as-built specimen can be ascribed to multiple Burgers orientation relationships among the prior β-phase, α-laths, and nanosized β-phase precipitates, which are not clearly understood. The as-built texture was maintained during post-processing, suggesting that texture manipulation in EB-PBF fabrication is important for controlling the crystallographic orientations of the built components, even after post-processing. RTA allowed a precise quantification of the β-phase fraction, which was found to have increased in post-processed specimens. The results would contribute to a comprehensive understanding of the microstructural evolution of such alloys, which is vital for the modeling and optimization of alloy performance.

A fat fraction phantom for establishing new convolutional neural network to determine the pancreatic fat deposition

The determination of fat fraction based on Magnetic Resonance Imaging (MRI) requires extremely accurate data reconstruction for the assessment of pancreatic fat accumulation in medical diagnostics and biological research. In this study, the signal model of the oil and water emulsion was created with a 3.0 T field strength. We examined the quantification of the fat fraction from phantom and the intrapancreatic fat fraction using the techniques of magnetic resonance spectroscopy (MRS) and Iterative Decomposition with Echo Asymmetry and Least-Squares estimate (IDEAL) in magnetic resonance imaging (MRI). Additionally, we contrasted expert manual pancreatic fat assessment with MRS and IDEAL pancreatic fat fraction quantification. There was a strong connection between the true fat volume fraction and the fat fraction from IDEAL and MRS (R2 = 0.99 and 0.99, respectively). For both phantom and in vivo measurements, Pearson's correlation and linear regression analysis were used. The findings of the in vivo assessment revealed a variable correlation between the pancreatic fat fraction MRI readings. We also used MR-opsy for manual pancreatic fat fraction segmentation since it read pancreatic fat fractions more accurately than IDEAL and MRS, which aided in the development of machine learning's ability to assess pancreatic fat automatically.

HT-SIP: a semi-automated stable isotope probing pipeline identifies cross-kingdom interactions in the hyphosphere of arbuscular mycorrhizal fungi

BackgroundLinking the identity of wild microbes with their ecophysiological traits and environmental functions is a key ambition for microbial ecologists. Of many techniques that strive for this goal, Stable-isotope probing—SIP—remains among the most comprehensive for studying whole microbial communities in situ. In DNA-SIP, actively growing microorganisms that take up an isotopically heavy substrate build heavier DNA, which can be partitioned by density into multiple fractions and sequenced. However, SIP is relatively low throughput and requires significant hands-on labor. We designed and tested a semi-automated, high-throughput SIP (HT-SIP) pipeline to support well-replicated, temporally resolved amplicon and metagenomics experiments. We applied this pipeline to a soil microhabitat with significant ecological importance—the hyphosphere zone surrounding arbuscular mycorrhizal fungal (AMF) hyphae. AMF form symbiotic relationships with most plant species and play key roles in terrestrial nutrient and carbon cycling.ResultsOur HT-SIP pipeline for fractionation, cleanup, and nucleic acid quantification of density gradients requires one-sixth of the hands-on labor compared to manual SIP and allows 16 samples to be processed simultaneously. Automated density fractionation increased the reproducibility of SIP gradients compared to manual fractionation, and we show adding a non-ionic detergent to the gradient buffer improved SIP DNA recovery. We applied HT-SIP to 13C-AMF hyphosphere DNA from a 13CO2 plant labeling study and created metagenome-assembled genomes (MAGs) using high-resolution SIP metagenomics (14 metagenomes per gradient). SIP confirmed the AMF Rhizophagus intraradices and associated MAGs were highly enriched (10–33 atom% 13C), even though the soils’ overall enrichment was low (1.8 atom% 13C). We assembled 212 13C-hyphosphere MAGs; the hyphosphere taxa that assimilated the most AMF-derived 13C were from the phyla Myxococcota, Fibrobacterota, Verrucomicrobiota, and the ammonia-oxidizing archaeon genus Nitrososphaera.ConclusionsOur semi-automated HT-SIP approach decreases operator time and improves reproducibility by targeting the most labor-intensive steps of SIP—fraction collection and cleanup. We illustrate this approach in a unique and understudied soil microhabitat—generating MAGs of actively growing microbes living in the AMF hyphosphere (without plant roots). The MAGs’ phylogenetic composition and gene content suggest predation, decomposition, and ammonia oxidation may be key processes in hyphosphere nutrient cycling.1Ep-TvDfGR-SFqLGobimTCVideo

Short-term arsenic mobilization, labilization, and microbiological aspects after gasoline and diesel addition in tropical soils.

The effect of the presence of gasoline and diesel on the speciation and mobility of inorganic arsenic species in tropical topsoils was investigated. Topsoil samples (n = 25) were contaminated with gasoline and diesel (500mgkg-1) in laboratory and were incubated under unsaturated conditions and regular aeration for 21days. Speciation analysis and chemical fractionation were performed in the pore water from control, gasoline, and diesel-contaminated soil samples. Arsenic concentrations were compared to microbiological parameters (microbial metabolic quotient and soil basal breathing) and the presence of ArsM-harboring bacteria. The spike of gasoline and diesel to the topsoils increased pore water As3+ (H3AsO3) concentration. Arsenic mobilization was lower compared to previously reported data for other sources of organic matter (biochar, litter, and a mixture of sphagnum peat moss and composted poultry manure). However, gasoline or diesel addition mobilized As fractions that were adsorbed to the solid phase, in approximately 60% of the soils. Methylation presented an important role in the As3+ regulation in control soils, which was no longer observed after gasoline or diesel addition. The quantification of the labile fractions sampled by the diffusive gradients in thin films technique showed that the increased As concentration in the gasoline or diesel-contaminated soils mostly included inert species. Dissolved organic carbon content seems to be an important control mechanism of the labile As concentration. The increase in As mobility seems to pose a more concerning scenario due to As leaching than to plant uptake.

Abstract 12664: Comprehensive Histological Analysis of Endomyocardial Biopsy and T1 Mapping for Predicting Left Ventricular Reverse Remodeling in Patients with Recent-Onset Dilated Cardiomyopathy

Background: Cardiomyocyte injury is a key pathological pathway in the progression of heart failure that predicts a poor prognosis; therefore, combined assessment of myocardial fibrosis and cardiomyocyte DNA damage from endomyocardial biopsy (EMB) samples may be of great importance. Meanwhile, cardiovascular magnetic resonance (CMR) native T1 reflects a composite of both intra- and extracellular compartments in the whole myocardium. We sought to assess the performance of native T1 mapping and EMB results to predict left ventricular reverse remodeling (LVRR) in recent-onset dilated cardiomyopathy (DCM). Methods: A total of 29 patients with DCM underwent cine CMR and triple-slice T1 mapping using the MOLLI sequence at 3T, and EMB before receiving guideline-directed medical therapy. Poly ADP-ribose (PAR) nuclear and sirius-red staining were used for quantification of DNA damage and collagen volume fraction (CVF), respectively. LVRR was defined as an increase in LV ejection fraction of ≥10% to the final value of &gt;35%, accompanied by a decrease in LV end-diastolic volume ≥10% at the follow-up CMR. Results: Fifteen patients (52%) achieved LVRR. The mean native T1, histological CVF, and proportion of PAR-positive nuclei were 1376 ± 55 ms, 0.13 ± 0.05, 25 ± 15%, respectively. Native T1 correlated well with CVF (p=0.004) and trended to be higher in DCM patients with increased DNA damage (p=0.17). There was no significant association between CVF and %PAR-positive nuclei. Native T1 &lt;1400 ms provided 86% sensitivity and 67% specificity, with the C-statistic of 0.82 (95% CI 0.67-0.98) for predicting LVRR. By contrast, C-statistic of %PAR nuclei, CVF, and combined assessment of %PAR nuclei and CVF were 0.59, 0.61 and 0.66, respectively. Conclusion: CMR T1 mapping may be a promising strategy for noninvasive biopsy of the whole heart and provide a better prediction of LVRR in recent-onset DCM than comprehensive histological analysis of EMB.

Pulse-echo speed-of-sound imaging using convex probes

Computed ultrasound tomography in echo mode (CUTE) is a new ultrasound (US)-based medical imaging modality with promise for diagnosing various types of disease based on the tissue’s speed of sound (SoS). It is developed for conventional pulse-echo US using handheld probes and can thus be implemented in state-of-the-art medical US systems. One promising application is the quantification of the liver fat fraction in fatty liver disease. So far, CUTE was using linear array probes where the imaging depth is comparable to the aperture size. For liver imaging, however, convex probes are preferred since they provide a larger penetration depth and a wider view angle allowing to capture a large area of the liver. With the goal of liver imaging in mind, we adapt CUTE to convex probes, with a special focus on discussing strategies that make use of the convex geometry in order to make our implementation computationally efficient. We then demonstrate in an abdominal imaging phantom that accurate quantitative SoS using convex probes is feasible, in spite of the smaller aperture size in relation to the image area compared to linear arrays. A preliminary in vivo result of liver imaging confirms this outcome, but also indicates that deep quantitative imaging in the real liver can be more challenging, probably due to the increased complexity of the tissue compared to phantoms.

Improving quantitation of nanoparticle concentrations in mixtures of known components using single particle inductively coupled plasma mass spectrometry with kernel density estimation

Accurate quantification of nanoparticle fractions in polydisperse mixture is challenging for many analytical techniques. For single particle inductively coupled plasma mass spectrometry (spICP-MS) where pulse signals are correlated to nanoparticles size and number concentration, data processing is crucial. The state-of-the-art algorithms distinguish particulate components with size difference of more than about 20 nm. In this work, a Bayes discriminant analysis based on a finite mixture model consisting of kernel density estimation (FMKDE) has been applied for spICP-MS, resulting in an unprecedented improvement in size resolution. Compared to existing data processing methods, the FMKDE model provides highly accurate contents due to the flexibility of the kernel density estimation for probability density. The gold nanoparticle mixtures have been used to verify the comparison. The size discrimination limit for gold mixtures can be decreased to about 5 nm with resolvable component content of <10% using the FMKDE model. The quantified number concentrations are also consistent with the designed values for the prepared mixtures with absolute biases of <3%. This study improves the size resolution of spICP-MS which could broaden its applicability in particle mixtures.