Diffusion Of Water Molecules Research Articles

Nigral diffusivity, but not free water, correlates with iron content in Parkinson's disease.

The loss of melanized neurons in the substantia nigra pars compacta is a primary feature in Parkinson’s disease. Iron deposition occurs in conjunction with this loss. Loss of nigral neurons should remove barriers for diffusion and increase diffusivity of water molecules in regions undergoing this loss. In metrics from single-compartment diffusion tensor imaging models, these changes should manifest as increases in mean diffusivity and reductions in fractional anisotropy as well as increases in the free water compartment in metrics derived from bi-compartment models. However, studies examining nigral diffusivity changes from Parkinson’s disease with single-compartment models have yielded inconclusive results and emerging evidence in control subjects indicates that iron corrupts diffusivity metrics derived from single-compartment models. We aimed to examine Parkinson’s disease-related changes in nigral iron and diffusion measures from single- and bi-compartment models as well as assess the effect of iron on these diffusion measures in two separate Parkinson’s cohorts. Iron-sensitive data and diffusion data were analysed in two cohorts: First, a discovery cohort consisting of 71 participants (32 control participants and 39 Parkinson’s disease participants) was examined. Second, an external validation cohort, obtained from the Parkinson’s Progression Marker’s Initiative, consisting of 110 participants (58 control participants and 52 Parkinson’s disease participants) was examined. The effect of iron on diffusion measures from single- and bi-compartment models was assessed in both cohorts. Measures sensitive to the free water compartment (discovery cohort: P = 0.006; external cohort: P = 0.01) and iron content (discovery cohort: P < 0.001; validation cohort: P = 0.02) were found to increase in substantia nigra of the Parkinson’s disease group in both cohorts. However, diffusion markers derived from the single-compartment model (i.e. mean diffusivity and fractional anisotropy) were not replicated across cohorts. Correlations were seen between single-compartment diffusion measures and iron markers in the discovery cohort (iron-mean diffusivity: r = −0.400, P = 0.006) and validation cohort (iron-mean diffusivity: r = −0.387, P = 0.003) but no correlation was observed between a measure from the bi-compartment model related to the free water compartment and iron markers in either cohort. In conclusion, the variability of nigral diffusion metrics derived from the single-compartment model in Parkinson’s disease may be attributed to competing influences of increased iron content, which tends to drive diffusivity down, and increases in the free water compartment, which tends to drive diffusivity up. In contrast to diffusion metrics derived from the single-compartment model, no relationship was seen between iron and the free water compartment in substantia nigra.

Multiparametric MRI analysis for the evaluation of renal function in patients with hyperuricemia: a preliminary study

BackgroundTo investigate the renal dysfunction in patients with hyperuricemia by employing a multiparametric MRI protocol, consisting of quantitative water molecule diffusion, microstructure, microscopic perfusion, and oxygenation measurements in kidneys.Materials and methodsA total of 48 patients with hyperuricemia (HU) and 22 age-matched healthy control subjects (HC) were enrolled in the study. For each participant, three different functional magnetic resonance imaging (fMRI) sequences were acquired and analyzed, including intravoxel incoherent motion imaging (IVIM), diffusion tensor imaging (DTI), and blood-oxygen-level-dependent MRI (BOLD). Thereafter, an independent two-sample t-test was applied to discover the significant differences of MRI indices between the hyperuricemia (HU) and HC groups, and the specific potential biomarkers between two subgroups of HU group (asymptomatic hyperuricemia group (AH) and gouty arthritis group (GA)). Further, multivariate logistic regression analyses were performed to classify the AH from the GA group using the MRI indices with significant between-group differences. The receiver operating characteristic (ROC) curve was plotted, and the area under the ROC curve (AUC) was calculated to assess the performance of each MR index for differentiation between the AH and GA groups.ResultsTen parametric values of the HU group were significantly lower than those of the HC group among the 14 fMRI parameters (P < 0.05). The cortical D, D*, and f values and medullary D and R2*values had significant differences between the AH and GA groups (P < 0.05). Combining the cortical D and f values and medullary R2* value gave the best diagnostic efficacy, yielding an AUC, sensitivity, and specificity of 0.967 ± 0.022, 91.67%, and 95.83%, respectively.ConclusionsA multiparametric MR analysis plays an important role in the evaluation of renal dysfunction in hyperuricemia from multiple perspectives. It could be a promising method for noninvasive detection and identification of the early-stage renal damage induced by hyperuricemia.

How polar hydroxyl groups affect surface hydrophobicity on model talc surfaces

Based on molecular dynamics simulations, we have studied the wetting behaviors of water on the talc-like surface with different surface polarity by modifying the charge distribution of surface hydroxyl (–OH) groups. With the change of the charge of the hydrogen atom (denoted as δ q ) in –OH group, the contact angle decreases from 91° to 50° and then remains constant. On the surfaces with the larger charge of hydrogen atoms (δ q ≥ 0.2 e), a water droplet is formed above a water monolayer, which is exactly contacted on the surface. Each water molecule in the monolayer forms one hydrogen bond (H bond) with surface –OH groups, without participating in any H bond with the water molecules within the monolayer or with the water molecules above the monolayer. The polarity of the –OH group also has a great influence on the dynamic behaviors of the interface water, such as residence time, hydrogen bond lifetime and self-diffusion coefficient. The diffusion of water molecules in the water monolayer near the highly polar surface is greatly suppressed, and the residence time of water molecules in the water monolayer even exceeds 12 ns.

Characterizing Mass-Transfer mechanism during gas hydrate formation from water droplets

Understanding the transport properties of water and guest molecules in dense hydrate structures is pivotal in controlling their formation and stability; this is nevertheless hindered by challenges in characterizing the time-varying diffusion and permeation process. This paper reports experimental results on the mass-transfer characteristics of water and guest molecules across hydrate shells during their formation from water droplets. The time-dependent 3D morphologies and parameters of hydrate shells were in-situ obtained via X-ray computed tomography to reveal the transport mechanism in hydrates. It was found that in the mass-transfer-limited stage, hydrate growth occurred primarily at the hydrate-gas interface, indicating a more mobile characteristic of water molecules in those hydrate shells than gas. The resulting outward permeation of water led to the growth of hydrate protrusions on the outer surface of the hydrate shell, suggesting a transition of the water transport schema through the hydrate shell from diffusion to permeation. Consequently, a diffusion-based shell growth model was developed to quantify the diffusivity of gas and water molecules in hydrates. Combining the measurements in the temperature range of 275.15–283.15 K, the effective diffusion coefficient of gas through the hydrates was estimated to be in the range of 1.34 × 10−14 − 1.90 × 10−13 m2/s, with that of interstitial water in the range of 2.87 × 10−12 − 3.83 × 10−11 m2/s. These results are of fundamental value in developing an improved understanding of the kinetics of hydrate formation from gas-water interfaces, which is essential in the optimization of hydrate-based techniques.

Gadolinium-free assessment of synovitis using diffusion tensor imaging.

The dynamic contrast-enhanced (DCE)-MRI parameter Ktrans can quantify the intensity of synovial inflammation (synovitis) in knees with osteoarthritis (OA), but requires the use of gadolinium-based contrast agent (GBCA). Diffusion tensor imaging (DTI) measures the diffusion of water molecules with parameters mean diffusivity (MD) and fractional anisotropy (FA), and has been proposed as a method to detect synovial inflammation without the use of GBCA. The purpose of this study is to (1) determine the ability of DTI to quantify the intensity of synovitis in OA by comparing MD and FA with our imaging gold standard Ktrans within the synovium and (2) compare DTI and DCE-MRI measures with the semi-quantitative grading of OA severity with the Kellgren-Lawrence (KL) and MRI Osteoarthritis Knee Score (MOAKS) systems, in order to assess the relationship between synovitis intensity and OA severity. Within the synovium, MD showed a significant positive correlation with Ktrans (r= 0.79, p< 0.001), while FA showed a significant negative correlation with Ktrans (r= -0.72, p= 0.0026). These results show that DTI is able to quantify the intensity of synovitis within the whole synovium without the use of exogenous contrast agent. Additionally, MD, FA, and Ktrans values did not vary significantly when knees were separated by KL grade (p= 0.15, p= 0.32, p= 0.41, respectively), while MD (r= 0.60, p= 0.018) and Ktrans (r= 0.62, p= 0.013) had a significant positive correlation and FA (r= -0.53, p= 0.043) had a negative correlation with MOAKS. These comparisons indicate that quantitative measures of the intensity of synovitis may provide information in addition to morphological assessment to evaluate OA severity. Using DTI to quantify the intensity of synovitis without GBCA may be helpful to facilitate a broader clinical assessment of the severity of OA.

Tribological behavior of short carbon fiber reinforced polyetherimide composite under water lubrication conditions

Short-carbon-fiber-reinforced polyetherimide (SCF/PEI) composites have good mechanical properties and are expected to have wide applications including components serving under water lubrication conditions. However, no work has been reported on the tribological behaviors of SCF/PEI composites under water lubrication conditions. This work attempts to explore the practicality of the SCF/PEI composite from a tribological point of view under water lubrication conditions. SCFs are coated by polydopamine (PDA) to enhance the interfacial interaction between fibers and matrix. The tribological performances of SCF/PEI composite are systematically investigated by sliding wear tests under tap and sea water lubrication conditions. Experimental results show that the SCF/PEI composite has a better friction performance in water lubrications than that under dry sliding because of the separation effects formed by a water molecule film and a transfer film. However, no remarkable differences of wear resistance are found between water lubrication and dry contact conditions, and the magnitude of specific wear rate under these conditions is around 1 × 10−6 mm3/N·m. It is found that contact surface hardness of the SCF/PEI composite is reduced after a sliding test in water due to the plasticization phenomenon, especially sea water can accelerate the diffusion of water molecules into matrix, making the specific wear rate in sea water is ten times of that in tap water for highly-loaded conditions. Meanwhile, the abrasive wear is observed to be the dominated wear mode in boundary lubrication regime, and the adhesion wear occurs around the transition position from the boundary to mixed lubrication regime. It is also found that pressure has a significant effect on the temperature rise within the contact surface than the speed does. Finally, the tribological performance of the SCF/PEI composite under water is exhibited to be better than that of most of polymers and composites reported previously.

Diffusion study of chloride and binding of water in concrete pore by molecular dynamics simulation using LAMMPS

As for the communication between concrete and the particles, the surface shows Cl− shock and Na adsorption. With expanded particle focus, the solid adsorption capacity for Cl− is upgraded as a result of a detailed overview of the dynamic molecular simulation studies examining the chloride diffusion coefficient. Different characteristics of the diffusion process, including molecular models, system-size effects, temperature, and pressure conditions, and the type of protection, are discussed. This paper focus on Molecular Dynamic Simulation to determine the diffusion coefficient of chloride ion and water molecules in concrete. The diffusion coefficient for NaCl salt obtained 6.60178x10-10m2/s and the diffusion coefficient for CaCl2 salt obtained 7.29305x10-10m2/s. So, the average chloride diffusion coefficient 6.9475x10-10m2/s. Diffusion coefficient obtained from graph 5.562x10-10m2/s. Diffusion coefficients for water molecules for NaCl solution are 6.125x10-10m2/s, 6.85x10-10m2/s, 1.044x10-10m2/s, 8.525x10-10m2/s, 6.25x10-10m2/s. diffusion coefficient of water molecules in CaCl2 solution are 4.5x10-10m2/s, 6.725x10-10m2/s, 1.254x10-10m2/s, 7.725x10-10m2/s, 1.3x10-10m2/s. Average value obtained for water molecule diffusion are 4.545x10-10m2/s, 7.4062x10-10m2/s and 1.149x10-10m2/s. This diffusion of chloride effects the binding of water in concrete pore.

Review of diffusion-weighted imaging and dynamic contrast-enhanced MRI for multiple myeloma and its precursors (monoclonal gammopathy of undetermined significance and smouldering myeloma).

The last decades, increasing research has been conducted on dynamic contrast-enhanced and diffusion-weighted MRI techniques in multiple myeloma and its precursors. Apart from anatomical sequences which are prone to interpretation errors due to anatomical variants, other pathologies and subjective evaluation of signal intensities, dynamic contrast-enhanced and diffusion-weighted MRI provide additional information on microenvironmental changes in bone marrow and are helpful in the diagnosis, staging and follow-up of plasma cell dyscrasias. Diffusion-weighted imaging provides information on diffusion (restriction) of water molecules in bone marrow and in malignant infiltration. Qualitative evaluation by visually assessing images with different diffusion sensitising gradients and quantitative evaluation of the apparent diffusion coefficient are studied extensively. Dynamic contrast-enhanced imaging provides information on bone marrow vascularisation, perfusion, capillary resistance, vascular permeability and interstitial space, which are systematically altered in different disease stages and can be evaluated in a qualitative and a (semi-)quantitative manner. Both diffusion restriction and abnormal dynamic contrast-enhanced MRI parameters are early biomarkers of malignancy or disease progression in focal lesions or in regions with diffuse abnormal signal intensities. The added value for both techniques lies in better detection and/or characterisation of abnormal bone marrow otherwise missed or misdiagnosed on anatomical MRI sequences. Increased detection rates of focal lesions or diffuse bone marrow infiltration upstage patients to higher disease stages, provide earlier access to therapy and slower disease progression and allow closer monitoring of high-risk patients. Despite promising results, variations in imaging protocols, scanner types and post-processing methods are large, thus hampering universal applicability and reproducibility of quantitative imaging parameters. The myeloma response assessment and diagnosis system and the international myeloma working group provide a systematic multicentre approach on imaging and propose which parameters to use in multiple myeloma and its precursors in an attempt to overcome the pitfalls of dynamic contrast-enhanced and diffusion-weighted imaging.Single sentence summary statementDiffusion-weighted imaging and dynamic contrast-enhanced MRI provide important additional information to standard anatomical MRI techniques for diagnosis, staging and follow-up of patients with plasma cell dyscrasias, although some precautions should be taken on standardisation of imaging protocols to improve reproducibility and application in multiple centres.

Effects of Hydration and Temperature on the Microstructure and Transport Properties of Nafion Polyelectrolyte Membrane: A Molecular Dynamics Simulation.

To investigate the effects of temperature and hydration on the microstructure of polymer electrolyte membrane and the transport of water molecules and hydronium ions, molecular dynamics simulations are performed on Nafion 117 for a series of water contents at different temperatures. The interactions among the sulfonate groups, hydronium ions, and water molecules are studied according to the analysis of radial distribution functions and coordination numbers. The sizes and connectivity of water clusters are also discussed, and it is found that the hydration level plays a key role in the phase separation of the membrane. However, the effect of the temperature is slight. When the water content increases from 3.5 to 16, the size of water clusters in the membrane increases, and the clusters connect to each other to form continuous channels for diffusion of water molecules and hydronium ions. The diffusion coefficients are estimated by studying the mean square displacements. The results show that the diffusion of water molecules and hydronium ions are both enhanced by the increase of the temperature and hydration level. Furthermore, the diffusion coefficient of water molecules is always much larger than that of hydronium ions. However, the ratio of the diffusion coefficient of water molecules to that of hydronium ions decreases with the increase of water content.

Moisture-induced autonomous surface potential oscillations for energy harvesting

A variety of autonomous oscillations in nature such as heartbeats and some biochemical reactions have been widely studied and utilized for applications in the fields of bioscience and engineering. Here, we report a unique phenomenon of moisture-induced electrical potential oscillations on polymers, poly([2-(methacryloyloxy)ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide-co-acrylic acid), during the diffusion of water molecules. Chemical reactions are modeled by kinetic simulations while system dynamic equations and the stability matrix are analyzed to show the chaotic nature of the system which oscillates with hidden attractors to induce the autonomous surface potential oscillation. Using moisture in the ambient environment as the activation source, this self-excited chemoelectrical reaction could have broad influences and usages in surface-reaction based devices and systems. As a proof-of-concept demonstration, an energy harvester is constructed and achieved the continuous energy production for more than 15,000 seconds with an energy density of 16.8 mJ/cm2. A 2-Volts output voltage has been produced to power a liquid crystal display toward practical applications with five energy harvesters connected in series.

Effect of additive concentration on water solution under vacuum ambient: A molecular dynamics simulation study

In order to explore the effect of different concentrations of additives on aqueous solution in vacuum ambient, this paper uses molecular dynamics simulation method to study different concentrations of magnesium chloride (MgCl2) aqueous solution, ethylene glycol aqueous solution and nano iron oxide (nano-Fe3O4) aqueous solution. The radial distribution function of atoms, the water molecules’ self-diffusion coefficient and the type and number of hydrogen bonds are analyzed in detail. The dynamic behavior between water molecules and chloride and alcohol molecules in the solution is revealed. The results show that the additives affect the crystallization of the solution by inhibiting the self-diffusion rate of water molecules, and the iron oxide nanoclusters exhibit the most obvious behavior. Meanwhile, the added additives can also restrain the formation of hydrogen bonds between water molecules in solution. This suppresses the hydrogen bonds between two water molecules. At the same time, it reduces the diffusivity of water molecules. These effects weaken the tendency of water molecules to migrate to the nucleus, and can curb the nucleation and growth of ice crystals in the aqueous solution to a certain extent. This research will provide reference value in the selection of ice-making working fluid. Nano-iron oxide has better performance than MgCl2, and glycol solution is not conducive to vacuum ice making.

Characterizing Sensorimotor-Related Area Abnormalities in Amyotrophic Lateral Sclerosis: An Intravoxel Incoherent Motion Magnetic Resonance Imaging Study

To investigate the microperfusion and water molecule diffusion alterations in sensorimotor-related areas in amyotrophic lateral sclerosis (ALS) using intravoxel incoherent motion (IVIM) magnetic resonance imaging. IVIM data were obtained from 43 ALS patients and 31 controls. This study employed the revised ALS Functional Rating Scale (ALSFRS-R) in evaluating disease severity. IVIM-derived metrics were calculated, including diffusion coefficient (D), pseudo-diffusion coefficient, and perfusion fraction. Conventional apparent diffusion coefficient was also computed. Atlas-based analysis was conducted to detect between-group difference in these metrics in sensorimotor-related gray/white matter areas. Spearman correlation analysis was employed to establish correlation between various metrics and ALSFRS-R. ALS patients had perfusion fraction (× 10-3) reduction in the left presupplementary motor area (60.72 ± 16.15 vs. 71.15 ± 12.98, p=0.016), right presupplementary motor area (61.35 ± 17.02 vs. 72.18 ± 14.22, p=0.016), left supplementary motor area (55.73 ± 12.29 vs. 64.12 ± 9.17, p=0.015), and right supplementary motor area (56.53 ± 11.93 vs. 63.67 ± 10.03, p=0.020). Patients showed D (× 10-6 mm2/s) increase in a white matter tract projecting to the right ventral premotor cortex (714.20 ± 39.75 vs. 691.01 ± 24.53, p=0.034). A negative correlation between D of right ventral premotor cortex tract and ALSFRS-R score was observed (r=-0.316, p=0.039). These findings suggest aberrant microperfusion and water molecule diffusion in the sensorimotor-related areas in ALS patients, which are associated with motor impairment in ALS.

P-010. Short-term prediction of preeclampsia using the sFlt-1/PlGF ratio in pregnant women with suspected preeclampsia

Short-carbon-fiber-reinforced polyetherimide (SCF/PEI) composites have good mechanical properties and are expected to have wide applications including components serving under water lubrication conditions. However, no work has been reported on the tribological behaviors of SCF/PEI composites under water lubrication conditions. This work attempts to explore the practicality of the SCF/PEI composite from a tribological point of view under water lubrication conditions. SCFs are coated by polydopamine (PDA) to enhance the interfacial interaction between fibers and matrix. The tribological performances of SCF/PEI composite are systematically investigated by sliding wear tests under tap and sea water lubrication conditions. Experimental results show that the SCF/PEI composite has a better friction performance in water lubrications than that under dry sliding because of the separation effects formed by a water molecule film and a transfer film. However, no remarkable differences of wear resistance are found between water lubrication and dry contact conditions, and the magnitude of specific wear rate under these conditions is around 1 × 10−6 mm3/N·m. It is found that contact surface hardness of the SCF/PEI composite is reduced after a sliding test in water due to the plasticization phenomenon, especially sea water can accelerate the diffusion of water molecules into matrix, making the specific wear rate in sea water is ten times of that in tap water for highly-loaded conditions. Meanwhile, the abrasive wear is observed to be the dominated wear mode in boundary lubrication regime, and the adhesion wear occurs around the transition position from the boundary to mixed lubrication regime. It is also found that pressure has a significant effect on the temperature rise within the contact surface than the speed does. Finally, the tribological performance of the SCF/PEI composite under water is exhibited to be better than that of most of polymers and composites reported previously.

Humidity Sensing Properties and Negative Differential Resistance Effects of TiO2 Nanowires

This paper reports a humidity sensor based on TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> nanowires. The humidity sensor prepared with a simple and easy technology exhibits obviously high sensitivity and fast response/recovery speed. A series of analyses including scanning electron microscopy, specific surface area analysis, water contact angle, and complex impedance spectrum were used to analyze superior humidity sensing performance of TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> nanowires. The results demonstrate that higher sensitivity of the sensor probably stems from larger specific area of nanowires, and its faster response might be attributed to the continuity of nanowires and their intricate connection network, which offer highways for water molecules diffusion and charges transport. Besides, the current-voltage characteristic of the sensor presents a negative differential resistance effect (NDR) with a very low bias voltage under certain humidity level at room temperature, which facilitates compatibility with some low voltage integrated circuit. The tip enhancement of electric field caused by TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> nanowire end is suggested to explain the mechanism of NDR at very low bias voltage. The high-performance humidity sensor provides a way to study the gender difference in moisture loss through skin evaporation with a non-contact manner, which can avoid the interference of contact state between the sensor and the skin.

Application of Community Detection Algorithm to Investigate the Correlation between Imaging Biomarkers of Tumor Metabolism, Hypoxia, Cellularity, and Perfusion for Precision Radiotherapy in Head and Neck Squamous Cell Carcinomas.

Simple SummaryIntegration of multimodality imaging (MMI) methods in head and neck squamous cell carcinomas (HNSCC) provides complementary information of the tumor and its microenvironment. Quantitative positron emission tomography (PET)/computed tomography (CT), DW- and DCE-MRI provide the functional information of tumor tissue based on metabolic process, diffusion of water molecules, and enhancement of water proton relaxation with a contrast agent, respectively. The present study aimed to investigate correlations at pre-treatment between quantitative imaging metrics derived from FDG-PET/CT(SUL), FMISO-PET/CT (K1, k3, TBR, and DV), DW-MRI (ADC, IVIM [D, D*, and f]), and FXR DCE-MRI [Ktrans, ve, and τi]) using a community detection algorithm (CDA) based on the “spin-glass model” and Spearman rank analysis in patients with HNSCC. Correlations between MMI-derived quantitative metrics evaluated using a CDA in addition to the Spearman analysis in a larger population may enable the identification of potential biomarkers for prognostication and management of patients with HNSCC.The present study aimed to investigate the correlation at pre-treatment (TX) between quantitative metrics derived from multimodality imaging (MMI), including 18F-FDG-PET/CT, 18F-FMISO-PET/CT, DW- and DCE-MRI, using a community detection algorithm (CDA) in head and neck squamous cell carcinoma (HNSCC) patients. Twenty-three HNSCC patients with 27 metastatic lymph nodes underwent a total of 69 MMI exams at pre-TX. Correlations among quantitative metrics derived from FDG-PET/CT (SUL), FMSIO-PET/CT (K1, k3, TBR, and DV), DW-MRI (ADC, IVIM [D, D*, and f]), and FXR DCE-MRI [Ktrans, ve, and τi]) were investigated using the CDA based on a “spin-glass model” coupled with the Spearman’s rank, ρ, analysis. Mean MRI T2 weighted tumor volumes and SULmean values were moderately positively correlated (ρ = 0.48, p = 0.01). ADC and D exhibited a moderate negative correlation with SULmean (ρ ≤ −0.42, p < 0.03 for both). K1 and Ktrans were positively correlated (ρ = 0.48, p = 0.01). In contrast, Ktrans and k3max were negatively correlated (ρ = −0.41, p = 0.03). CDA revealed four communities for 16 metrics interconnected with 33 edges in the network. DV, Ktrans, and K1 had 8, 7, and 6 edges in the network, respectively. After validation in a larger population, the CDA approach may aid in identifying useful biomarkers for developing individual patient care in HNSCC.

Impacts of Polar Molecules of Crude Oil on Spontaneous Imbibition in Calcite Nanoslit: A Molecular Dynamics Simulation Study

Spontaneous imbibition is a crucial method for developing tight reservoirs. The interactions between fluid and solid are key to imbibition behavior. In this work, the molecular simulation method was used to study the occurrence state of polar molecules in calcite nanoslit and the mechanisms of their impacts on spontaneous imbibition. The results showed that both adsorption energy and molecular orientation were key parameters for characterization of the occurrence state of polar molecules. The temperature and average area controlled by each polar molecule affected the adsorption energy by changing the molecular orientation, and the quantitative relationship was established by the regression analysis method. During spontaneous imbibition, polar molecules affect imbibition by delaying the advance of water molecules in the first hydration layer, and the degree of delay depends on the synergistic effect of the adsorption energy and the molecular orientation. By coupling the adsorption energy and order parameters, a concept of a steric hindrance factor was proposed. The spontaneous imbibition process in calcite nanoslit can be divided into two periods, a linear period and a plateau period, but it experiences a short elastic period before spontaneous imbibition. The recovery degree of octane in the elastic period is only related to temperature and that in the linear period is related to the temperature and steric hindrance factors. Temperature promotes the diffusion of water molecules to the deep pore and reduces the steric hindrance factor, which further reduces the inhibiting effect on water molecules. Finally, a prediction model for the recovery degree of octane in calcite nanoslit with polar molecules is proposed, which provides theoretical guidance for improving the spontaneous imbibition recovery of tight carbonate reservoirs.

Humidity sensor based on cobalt Chloride/Cellulose Filter-Paper for respiration monitoring

With the spread of COVID-19, more and more attention has been paid to the self-monitoring of healthy breathing. In this paper, we propose a humidity sensor which is simple to manufacture, low cost, good flexibility and visualization. The humidity sensor based on cellulose filter paper (FP) exhibited a good moisture-dependent voltage response over a wide relative humidity (RH) range due to the capillary structure of porous cellulose films and highly hydrophilic material of cobalt chloride (CoCl 2 ), which facilitated water molecule adsorption and diffusion. The cellulose film colour shifted from blue to red when RH changed from 11% to 98%, and this colour shift was reversible. A moisture-driven sensor, based on the diffusive flow of water in cellulose networks, can provide an output voltage of 200 mV in a highly moist environment. Due to the high flexibility of cellulose fibres, the sensor maintained a constant output voltage even after 3000 folds. Moreover, the device was successfully applied for human respiratory monitoring and movement frequency tracking. The uniqueness of this new wearable humidity sensor technology can establish a new application field for the development of intelligent textiles and personal health products in the future Internet-of-things.

Microstructural characteristics of chronic infarct segments assessed using diffusion tensor imaging

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): British Heart Foundation Background The microstructural changes following myocardial infarction (MI) can be characterised in-vivo with cardiac diffusion tensor imaging (cDTI) imaging, using mean diffusivity (MD), fractional anisotropy (FA), secondary eigenvector angle (E2A) and helix angle (HA) maps. In this study, we use cDTI to explore the microstructural differences between subendocardial and transmural chronic infarct segments. Method Twenty STEMI patients (15 men, 5 women, mean age 59) underwent 3T CMR scan at 3 months following presentation (mean interval 107 ± 18 days). Scan protocol included: second order motion compensated (M012) free-breathing spin echo DTI (3 slices, 18 diffusion directions at b-values 100s/mm2[3], 200s/mm2[3] and 500s/mm2[12], acquired resolution was 2.20x2.27x8mm3; cine gradient echo and LGE imaging. Average MD, FA, E2A and HA parameters were calculated on a 16-AHA-segmental level. HA maps were described by dividing values into left-handed HA (LHM, -90° &amp;lt; HA &amp;lt; -30°), circumferential HA (CM, -30° &amp;lt; HA &amp;lt; 30°), and right-handed HA (RHM, 30° &amp;lt; HA &amp;lt; 90°) and reported as relative proportions. Infarct segments were identified using LGE; patients were categorised according to the maximal transmurality of their infarct segments, into subendocardial (&amp;lt;50% LGE) or transmural (&amp;gt;50% LGE) MI. Results DTI acquisition was successful in all patients (acquisition time 13 ± 5mins). Ten patients had transmural MI. The results are shown in table 1. Transmurally infarcted segments had significantly lower FA (FA subendocardial MI = 0.27 ± 0.04, FA transmural MI = 0.23 ± 0.02, p &amp;lt; 0.01), lower E2A (E2A subendocardial MI = 47 ± 7°, E2A transmural MI = 38 ± 6°, p &amp;lt; 0.01) and lower proportions of right-handed cardiomyocytes (RHM subendocardial MI = 21 ± 5%, RHM transmural MI = 14 ± 5%, p &amp;lt; 0.01) than subendocardial infarct segments. Conclusion Compared to subendocardial MI segments, the diffusion of water molecules is more isotropic in transmurally infarcted myocardium as evidenced by lower FA values, signifying increased structural disarray. The significantly lower E2A values suggest that laminar sheetlets of transmural infarct segments remain fixed at shallower angles during systole and are unable to reach their usual contractile configuration. The lower proportions of RHM on HA maps highlight the significantly greater loss of subendocardial cardiomyocytes in transmural infarct segments. Further studies are required to assess if these segmental changes can be predictive of long-term LV remodelling.

Enhancement of self-powered humidity sensing of graphene oxide-based triboelectric nanogenerators by addition of graphene oxide nanoribbons.

A triboelectric nanogenerator (TENG) electrode sensitive to the adsorption of water molecules has been introduced to create a self-powered humidity sensor. Graphene oxide (GO) nanosheets and graphene oxide nanoribbon (GONR) possessing oxygenated functional groups, as well as high dielectric constants, have been proposed as appropriate candidates for this purpose. GO papers have been fabricatedin three forms, i.e. pure GO paper, uniform composites of GONR and GO, and double-layer structures of GONR on top of GO. Results showed that all of the prepared paper-based TENGs revealed excellent performances by maximum output voltage above 300V. As active humidity sensors, the maximum voltage response values of 57%, 124%, and 78% were obtained for GO, GONR+GO, and GONR/GO TENGs, respectively. Besides high sensitivity and precisionof all variants, GO+GONR TENG demonstrated a rapid response/recovery behavior (0.3/0.5s). This phenomenon can be attributed to the higher oxygenated groups and defects on the edges of GONR, which leads to facilitating the bulk diffusion of water molecules. Our results open new avenues of GONR application as an additive to enhance the performance of self-powered humidity sensors, as well as conventional hygrometers.

Functional Imaging Detects Residual Disease in MRD-Negative Multiple Myeloma Patients Who Subsequently Relapse

IntroductionNovel agents have dramatically increased the rate of complete remission (CR) in patients with multiple myeloma (MM). As a result, the quality of CR is increasingly being assessed by molecular tests, such as multicolor flow cytometry (MFC) or next generation sequencing. In this context, the achievement of minimal residual disease negativity (MRDneg) has been reported to be associated with favorable outcomes, and recently it has been included as an additional criterium in the international myeloma working group (IMWG) response definition. Despite this, even MRDneg patients continue to relapse, probably due to residual disease at sites other than the one commonly investigated for MRD, the posterior iliac crest. In this work we have determined whether functional imaging can be used to detect residual disease in MRDneg patients and to address its value in the assessment of patients in CR. To investigate this we selected a unique group of patients who had relapsed from MRDneg CR and for whom two different functional imaging techniques were performed at the MRDneg CR stage and later at IMWG defined relapse.MethodsOf 294 patients treated with novel agents and autologous stem cell transplantation who had achieved MRDneg CR, assessed using 8 color MFC with a limit of detection between 10-4 and 10-5, we identified 46 who subsequently relapsed. Of these 62% were male with a median age of 64 (41-79) years, and 22% had unfavorable molecular features at baseline. 35 patients were newly diagnosed and achieved MRDneg CR during frontline therapy. The remaining 11 patients achieved MRDneg CR following salvage therapy post-relapse. The functional imaging tests used were 18F-FDG positron emission tomography with CT attenuation correction (PET-CT) and diffusion-weighted magnetic resonance imaging with background suppression (DWIBS). Using PET-CT, a FL was defined as a circumscribed focus with increased FDG uptake compared to its surroundings. For DWIBS, a FL was defined as a well delineated focal intensity above the surrounding background BM ≥1 cm in size and showing restriction on apparent diffusion coefficient maps.ResultsAt the time of MRDneg CR, functional imaging showed residual focal disease in 14 patients (30%). This is a surprisingly high number, which reflects our approach of focusing on patients who subsequently relapsed. For PET-CT, which measures the uptake of radioactive glucose, focal lesions were seen in 3 of 46 patients. DWIBS, which quantifies diffusion of water molecules, showed FLs in 12 patients (26%). This increased rate indicates that DWIBS is the more sensitive technique for this purpose. Interestingly, 9 of the 14 FL-positive patients exclusively presented with FLs outside the pelvis or contra-laterally to the site investigated for MRD detection, explaining the discordant results. Of note, in 7 of 14 patients FLs detectable at MRDneg CR progressed in size or restriction, strongly suggesting that residual clonal cells at these sites led to relapse. In 6 other patients there were either no FLs (n=3) or only new FLs (n=3). This observation indicates that the kinetics of achieving molecular MRD and imaging MRD may differ. At relapse 16 of the 44 patients (36%) remained MRDneg yet 13 were positive by at least one of the functional imaging techniques. Only 2 of these cases presented with FLs at the pelvic site of BM biopsy used for MRD detection. Interestingly, there was a trend to a higher proportion of the imaging-pos/MRDneg status in patients at later relapses compared to the ones at first relapse (Fisher's test P =0.06).ConclusionsFunctional imaging improves assessment of residual disease by accounting for the heterogeneous disease distribution in MM. The patchy character of MM BM involvement seems to increase after the first relapse, reducing the sensitivity of MRD diagnostics done exclusively on iliac crest samples. The sensitivity of DWIBS for detection of focal residual disease seems to be superior to PET-CT. However, future research is warranted to address the specificity of DWIBS, the glycolytic rate of residual MM cells and the potential suppression of FDG uptake by ongoing treatment. To further assess the specificity of functional imaging as a tool to predict relapse, we will analyze a set of 248 MM patients who remain in MRDneg CR and the results will be presented in the meeting. [Display omitted] DisclosuresBarlogie:Millenium Pharmaceuticals: Consultancy, Research Funding; Celgene Corporation: Consultancy, Research Funding. Davies:Bristol-Myers: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Morgan:Bristol Myers: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding.