Plasma Droplets Research Articles

Probing the shape of the quark-gluon plasma droplet via event-by-event quark-gluon plasma tomography

This study investigates quark-gluon plasma in heavy-ion collisions through two avenues: high-p⊥ frameworks and hydrodynamic modeling. Using the TRENTo model, we find that the p=0 value aligns well with high-p⊥ data, in agreement with Bayesian analysis of the low-p⊥ regime. While adjusting p values may improve a fit to a particular high-p⊥ observable, it does not permit an earlier onset of transverse expansion. Published by the American Physical Society 2024

A-171 Novel Fluorometric Assay for Pediatric Anti-Factor Xa Testing: Minimizing Bilirubin and Hemolysis Interference in Whole Blood

Abstract Background High bilirubin levels are common in pediatric patients and are noted in patients undergoing extracorporeal membrane oxygenation (ECMO). Acute anticoagulation therapy necessitates frequent monitoring of anti-Factor Xa activity (aFXa), and high bilirubin levels cause interference in chromogenic assays. Moreover, large volumes of blood lead to iatrogenic anemia in pediatric and neonatal patients. We developed a fluorescence assay to measure aFXa activity on a near-patient digital microfluidic (DMF) platform using low volume whole blood samples (< 50 μL) and present the results of interference of bilirubin and hemolysis on aFXa activity. Methods aFXa assay was performed on a DMF cartridge wherein 50 μL whole blood was loaded into the cartridge which separates plasma droplets through agglutination within the cartridge followed by incubation with a droplet containing exogenous FXa and a fluorogenic substrate. The fluorescence is inversely proportional to the concentration of heparin in the sample. All required reagents for the aFXa assay are dried within the cartridge, allowing for integrated sample preparation and assay automation for point of care use. To test the interference of bilirubin, we spiked into whole blood different concentrations of unconjugated bilirubin, ranging from 0-40 mg/dL. We also tested hemoglobin interference by testing 4 different concentrations of hemolysate (0-1,000 mg/dL) on the aFXa assay. All experiments were performed with 6 replicates of each concentration. Results Across each bilirubin concentration, we saw uniform measurements of aFXa activity (see Table). We observed < 5% CV in aFXa activity with 0, 13.33 and 26.67 mg/dL bilirubin levels. All measured unfractionated heparin values for hemolysate interference were <5% CV. Conclusions Our interference results suggest that high bilirubin and hemolysate levels do not interfere with our novel aFXa fluorescence assay. Further clinical studies are underway to establish clinical performance.

Atmospheric pressure plasma jet interacting with a droplet on dielectric surface

Abstract The chemical processes at plasma–liquid interface has become a crucial point for plasmas’ various applications. In this study, the interaction between atmospheric pressure plasma jet and different-scale droplets were investigated by both experiments and modeling. The interaction transited from ‘annular’ mode to ‘solid’ mode when plasma involved with different size of droplets. As the droplet size increased, the high-field region moved from the plasma jet head to the gap between plasma jet head and droplet vertex surface. Additionally, the time averaged surface fluxes of the main active species were analyzed. For the flux of singlet oxygen (1O2), both small and medium-scale droplets reached the maximum value in the central region of the droplets, while for large-scale droplet, the maximum value was observed in the edge region of the droplet. This was due to the fact that, compared to small and medium-scale droplet, the edges of large-scale droplet are closer to the He–Air mixed boundary layer, where more oxygen molecules were provided in the gas environment, leading to enhanced electron collision reactions with oxygen molecules. The cause for these behaviors were also analyzed and discussed. This work shed light on the interaction mechanism for plasma–liquid interactions, which provides significant guidance for plasma medical or water treatment applications.

Fluid simulations for a finite size plasma

Studies on finite-size plasma have attracted a lot of attention lately. They can form by ionizing liquid droplets by lasers. The dynamical behavior of such plasma droplets is, therefore, a topic of significant interest. In particular, questions related to the linear and nonlinear characteristics (associated with the inhomogeneous density typically at the edge of the droplet), the behavior of plasma expansion, etc., are of interest. A one-dimensional fluid simulation study has been carried out to investigate this behavior. It is observed that a slight imbalance in the charge density leads to oscillations that are concentrated and keep acquiring higher amplitude and sharper profiles at the inhomogeneous edge region. Such oscillations lead to the expansion of the droplet. Though the fluid description breaks when the sharpness of these structures becomes comparable to the grid size, it provides a reasonable estimate of wave-breaking time. The presence of dissipative effects such as diffusion is shown to arrest the sharpness of these structures. The dynamics of these structures in the presence of an externally applied oscillating electric field corresponding to long wavelength radiation have also been studied.

Early-Stage Protein Adsorption Sequence on Blood-Contacting Surfaces: Answer to Vroman's Question.

Plasma protein adsorption on blood-contacting surfaces is the initiating significant event and modulates the subsequent coagulation response. Despite decades of research in this area, Vroman's questions in 1986 "Who gets there first?" and "When does the next protein arrive?" remain unanswered due to the lack of detection techniques with sufficient temporal resolution. In this work, we develop a droplet microfluidic technology to detect protein adsorption sequences on six typical blood-contacting surfaces in milliseconds. Apolipoproteins (Apo) are found to be the first proteins to adsorb onto the surfaces in a plasma droplet, and the specific type of apolipoprotein depends on the surface. Apo CI is the first protein adsorbed on gold, platinum, graphene, stainless steel, and polyvinyl chloride with the adsorption time varying from 0.01 to 1 s, while Apo CIII preferentially reaches the titanium alloy surface within 1 s. Subsequent to the initial adsorption, Apo AI, AII, and other proteins continue to adsorb until albumin arrives. Thus, the adsorption sequence is revealed, and Vroman's questions are answered. Moreover, this finding demonstrates the influence of the initial protein adsorption on subsequent coagulation at the surface, and it offers new insights into the development of anticoagulant surfaces.

Effects of Interface Morphology between Nitrogen Plasma and Fine Water Droplet for Ammonia Production Efficiency

Effects of Interface Morphology between Nitrogen Plasma and Fine Water Droplet for Ammonia Production Efficiency

Plasma ddPCR for the detection of MET amplification in advanced NSCLC patients: a comparative real-world study

Background: Mesenchymal–epithelial transition ( MET) amplification is a crucial oncogenic driver and a resistance mechanism to epidermal growth factor receptor tyrosine kinase inhibitors (TKIs) of non-small-cell lung cancer (NSCLC). Fluorescence in situ hybridization (FISH) is the gold standard for MET amplification detection. However, it is inapplicable when tissue samples are unavailable. Objective: This study assessed the performance of plasma droplet digital polymerase chain reaction (ddPCR) in MET amplification detection in NSCLC patients. Design and methods: A total of 87 NSCLC patients were enrolled, and 94 paired tissue and plasma samples were analyzed for the concordance between FISH and plasma ddPCR/tissue next-generation sequencing (NGS) in detecting MET amplification. In addition, the efficacy of patients with MET amplification using different detection methods who were treated with MET-TKIs was evaluated. Results: Plasma ddPCR showed substantial concordance with FISH (74.1% sensitivity, 92.5% specificity, and 87.2% accuracy with a kappa value of 0.68) and outperformed tissue NGS (kappa value of 0.64) in MET amplification detection. Combined plasma ddPCR and tissue NGS showed substantial concordance with FISH (92.3% sensitivity, 89.2% specificity, and an accuracy of 90.1% with a kappa value of 0.77). The efficacy is comparable in these NSCLC patients with MET amplification detected by FISH and plasma ddPCR who were treated with MET-TKIs. Conclusion: Plasma ddPCR is a potentially reliable method for detecting MET amplification in advanced NSCLC patients. Combined plasma ddPCR and tissue NGS might be an alternative or complementary method to MET amplification detection.

Strong Constraints on Jet Quenching in Centrality-Dependent p+Pb Collisions at 5.02TeV from ATLAS.

Jet quenching is the process of color-charged partons losing energy via interactions with quark-gluon plasma droplets created in heavy-ion collisions. The collective expansion of such droplets is well described by viscous hydrodynamics. Similar evidence of collectivity is consistently observed in smaller collision systems, including pp and p+Pb collisions. In contrast, while jet quenching is observed in Pb+Pb collisions, no evidence has been found in these small systems to date, raising fundamental questions about the nature of the system created in these collisions. The ATLAS experiment at the Large Hadron Collider has measured the yield of charged hadrons correlated with reconstructed jets in 0.36 nb^{-1} of p+Pb and 3.6 pb^{-1} of pp collisions at 5.02TeV. The yields of charged hadrons with p_{T}^{ch}>0.5 GeV near and opposite in azimuth to jets with p_{T}^{jet}>30 or 60GeV, and the ratios of these yields between p+Pb and pp collisions, I_{pPb}, are reported. The collision centrality of p+Pb events is categorized by the energy deposited by forward neutrons from the struck nucleus. The I_{pPb} values are consistent with unity within a few percent for hadrons with p_{T}^{ch}>4 GeV at all centralities. These data provide new, strong constraints that preclude almost any parton energy loss in central p+Pb collisions.

Searching for QGP droplets with high- pT hadrons and heavy flavor

The search for the smallest quark-gluon plasma (QGP) droplets in nature has motivated recent small collisions system programs at RHIC and LHC. Unambiguous identification of jet quenching due to final-state interactions is key to confirming QGP formation in these reactions. We compute the nuclear modification factors $R_{AA}$ and $R_{p(d)A}$ of charged hadrons and heavy flavor mesons in large (Au-Au, Xe-Xe, Pb-Pb) and small ($d$-Au, $p$-Pb, O-O) colliding systems, respectively. Our results include the Cronin effect and initial-state parton energy loss in cold nuclear matter. In the final state, hard partons undergo collisional energy loss and branching that was recently derived using Soft-Collinear-Effective-Theory with Glauber Gluon (SCET$_{\rm G}$). In large colliding systems, medium-modified QCD evolution of the fragmentation functions dominates the nuclear correction. As the system size decreases, we find that cold nuclear matter effects, collisional energy loss, and QGP-induced radiations can become equally important. A systematic scan over the medium size and mass/flavor dependence of $R_{AA}$ provides the opportunity to separate these individual contributions and identify QGP signatures in small systems. Predictions for $R_{AA}^{h}$, $R_{AA}^{D}$, $R_{AA}^{B}$ in O-O collisions at $\sqrt{s}=7$ TeV are presented with and without the formation of a QGP and contrasted with the corresponding $R_{p(d)A}$ calculations. Upcoming single-hadron measurements at the LHC will not only test the O-O predictions for both light and heavy flavor production, but will shed light on the possibly very different dynamics of $p$-A and A-A reactions at similar soft particle production multiplicities.

Dynamic behavior of biological droplets on heated, superhydrophobic microstructured surfaces

Severe adhesion of biological fluids occurs on surgical electrodes due to a temperature-induced physical mechanism. By constructing surface microstructures and improving their hydrophobicity, it becomes a favorable choice for electrode anti-adhesion, but the related mechanisms are still not fully understood. Herein, we investigated the dynamic behavior of water and biological droplets on superhydrophobic microstructured surfaces (SMSs) heated over 100 ℃. The design inspiration of SMSs is derived from purple orchid leaves with excellent self-cleaning properties. The SMSs with Cassie-Baxter and Cassie impregnating states were selected and a flat surface was employed for comparison. Results show that the SMSs with the Cassie-Baxter state could reduce the Leidenfrost point to form a pseudo-Leidenfrost effect for water droplets. Furthermore, the dynamic evolution mechanism of plasma droplets on heated surfaces was first proposed, including base shrinkage, coagulation growth, and cap convergence. For the SMSs with the Cassie-Baxter state, the heat was carried away by vapor from the cavities at the contact interface, so that the growth height of the coagulation was lower than that of other surfaces. Additionally, the mentioned SMSs exhibited outstanding anti-adhesion performance and thermal stability. This study may contribute to understanding the anti-adhesion mechanism of surgical electrodes at the microscopic level.

Enhanced water activation in gas–liquid two-phase flow using air plasma droplets

We report on our study of gas–liquid two-phase flow of air plasma and its associated dynamic behavior, droplet activity, and applications. The propagation of the air plasma jet within a Venturi configuration is significantly perturbed by the presence of water droplets due to the local modification of the electric field that results from polarization and charging of the droplets. This local modulation, in turn, decreases the discharge current pulses and the radiation intensity of optical emissions. With a change in inlet airflow dynamics from laminar to turbulent (5–10 L/min), the droplet diameter decreased exponentially under strong pressure from millimeter to several tens of micrometers, whereas the gas–droplet contact area increased substantially. The production of short-lived reactive aqueous species OH and O2− was enhanced at the gas–liquid interface of the biphasic plasma droplets, and the activities of different long-lived species (H2O2, NO3−, and O3) in the droplet were highly selective in droplet diameter and value of the Henry-law constants. This new plasma source architecture enables an in situ activation of water sprays by plasma jets at short time scales, providing a desirable and effective sterilization tool and wastewater treatment at a relatively low cost and ease of operation.

Enhanced cutting performance of electrosurgical units by oil-infused laser-textured surfaces

To enhance the cutting performance of electrosurgical units, urgent demands have been put forward for their work terminal, including an antiadhesion property and less thermal damage. Herein, an oil-infused surface (OIS) was fabricated by nanosecond laser texturing and spin-coating of medical olive oil and then applied to a work terminal (a scalpel). The effects of four laser scanning paths on the morphology of microdimples used for oil storage were investigated. Then, an array of 0° microdimples with vertical wall and symmetry features was selected to create OISs. The fabricated microdimples contained a nanoscale sponge-like morphology, which improved the oil storage capacity. From the point of view of experimental and theoretical analysis, we verified the autonomous sliding behaviour of plasma droplets on the inclined OIS, and the analysis of the viscosities of the oil film and a plasma droplet showed that the sliding velocity of the droplet decreased with increasing microdimple spacing. Cutting experiments proved that the OIS scalpel has excellent antiadhesion properties for multiple biological tissues. In particular, the OIS scalpel can reduce the cutting force by 19.0% and the tissue thermal damage by 30.8% when cutting pork tenderloin compared to the pristine scalpel. During the cutting process, the introduction of an oil film shifts the interfacial separation from within the tissue to the oil film itself, and the film acts as a thermal barrier to reduce tissue damage, thus greatly improving the cutting performance. The present study highlights the practical application of the OIS as an effective tool in the field of electrosurgical units.

Spatial and temporal dynamics of single nanosecond discharges in air with water droplets

Discharges generated in water or water-containing media have great potential for various technological applications. However, a fundamental understanding of plasma–liquid interactions, particularly the ignition and propagation of a discharge in a gap containing liquid droplets, is lacking. This study investigates the electrical characteristics and the spatial-temporal dynamics of nanosecond discharges in air containing one or two millimetric droplets of deionized water. Analysis of the effects of voltage amplitude (V a) and pulse width on the discharge mode shows that at low V a, the discharges are run in streamer mode; however, at high V a, a streamer-to-spark transition is observed. Although the droplet size (diameter between 2 and 4 mm) does not significantly influence the discharge dynamics, its position with respect to the gap (on- or off-axis) has a strong effect. Time-resolved imaging of three droplet configurations (one on-axis droplet, one off-axis droplet, and two on-axis droplets) was used to unveil the ignition and propagation dynamics of streamers and sparks at nanosecond time scale. The findings are of interest and contribute to a better understanding of` the plasma–droplet interactions, which is crucial for the development and optimization of plasma-based applications.

Electrothermally excited plasma droplet evolution on the laser-patterned surface

Droplet behavior involving electrothermal coupling fields has gradually attracted the attention of researchers, one of which includes electrosurgical scalpels that often contact biofluids. However, the evolution of bio-droplets exposed to the surface of electrosurgical scalpels is not yet well understood. Here, we experimentally studied the effect of different heating temperatures on plasma droplets on the laser-patterned surface (LPS) and the original surface (OS) under defined direct-current (DC) or alternating-current (AC) electric fields. The results show that at a lower heating temperature, the evolution of plasma droplets was dominated by electrolysis. Oxygen bubbles generated on the papillae on the LPS in the DC field inhibited the targeted adsorption of plasma proteins on this surface. In contrast, in the AC field, only a small number of bubbles was generated, which is not sufficient to inhibit protein adsorption, leading to the formation of coagulation on the papillae after heating. At higher heating temperatures, the rapid formation of coagulation resulted in the suppression of electrolysis. The plasma proteins were then transported by the Marangoni flow causing coagulation to reach a thickness of stress mutation. Stress release over the entire coagulation caused its edges to bend and then detach from the papillae. Thus, the LPS exhibited excellent anti-adhesive properties to plasma droplets under electrothermal excitations compared to the OS. This study provides valuable information for understanding the mechanisms of contact behavior between biofluids and electrosurgical scalpels and demonstrates great promise for their anti-adhesive performance.

Blood-repellent and anti-corrosive surface by spin-coated SWCNT layer on intravascular stent materials.

Despite intravascular bare metallic stents (BMS) being indispensable products in cardiovascular surgery, they face in-stent restenosis (ISR), resulting in stent failure or secondary surgical operation necessity. Accumulation or corrosion processes are key factors that promote ISR development in a vascular pathway, including an intravascular stent. The ISR can be inhibited by increasing the blood-repellency, and electrochemical corrosion resistance features using surface modification techniques on intravascular stent materials. In this study, Single-Walled Carbon Nanotube (SWCNT) structures were deposited using the spin-coating method on stent specimens made of 316L, 316LVM, CoCr-alloy, and Ti-alloy. Hydrophobicity and blood-repellency functions of coated and uncoated specimens were analysed by the Contact Angle (CA) values for distilled water (DIW), glycerol, blood plasma, and total-blood droplets using a computer-controlled goniometer system. Using a potentiostat, the electrochemical corrosion resistance features were analysed from obtained Electrochemical Impedance Spectroscopy (EIS) and Tafel curves in 37 °CSimulated Body Fluid (SBF) mimicking the human blood plasma. Due to the CA values below 90°, the repellency limit for hydrophobicity and blood-repellency, bare specimens performed hydrophilic and blood-philic features. However, SWCNT coating increased the repellency functions to 95°for DIW and 96°for total blood. The electrochemical corrosion resistance analysis showed that 1.433 kΩ cm2 polarization resistance and 1.07 kΩ cm2 electrochemical impedance of bare specimens increased to 142.8 kΩ cm2 and 141.3 kΩ cm2 by SWCNT coating. These corrosion resistance enhancements led to ratios of 78.13% inhibition in the corrosion rate and mass loss rate per year for SWCNT-coated 316LVM specimens. The maximum inhibition efficiency was observed for SWCNT-coated 316LVM specimens with a ratio of 87.92%. Obtained results indicate that SWCNT coating of the intravascular stents can inhibit the ISR risks of the BMS group.

Holographic entropy production in a Bjorken expanding hot and dense strongly coupled quantum fluid

The authors study the dynamics of droplets of quark-gluon plasma created in heavy iron collisions. The relativistic quantum fluid undergoes Bjorken flow expansion and is modeled as conformal $N=4$ supersymmetric Yang-Mills plasma. In particular, they investigate the holographic entropy production far from equilibrium where the horizon area is no longer a proper measure for the entropy but the area of a dynamic apparent horizon is assumed to be the right dual observable.

Soft polymerization of hexamethyldisiloxane by coupling pulsed direct‐liquid injections with dielectric barrier discharge

AbstractThis work examines the combination of pulsed direct‐liquid injections with dielectric barrier discharge at atmospheric pressure for the deposition of organosilicon coatings using hexamethyldisiloxane (HMDSO) as the precursor and nitrogen as the carrier gas. In such conditions, deposition relies on the charging of micrometer droplets and their transport toward the substrate by the Coulomb force. The thin‐film morphology and extent of precursor fragmentation are strongly linked to the amount of energy provided by the filamentary discharge to HMDSO droplets. While cross‐linked and smooth coatings were achieved at low energies as in standard gas phase plasma polymers, viscous and droplet‐like structured thin films were deposited at higher energies. The latter material is attributed to the soft polymerization of HMDSO droplets related to plasma–droplet interactions.

Three loop correction in the formation of QGP droplet

Quark–gluon plasma (QGP) droplet formation is re-considered with the addition of three loop correction to the earlier loop factors in the mean field potential. The correction of the three loop factor increases stability in the droplet formation of QGP at different parametrization factors of the QGP fluid and it is in a better agreement in comparison with the lattice results of pressure, energy density and other thermodynamic relations. This implies that the contribution of the three loop enhances in showing the characteristic features of the QGP fluid. It also shows that increasing the loop increased the strength of parametrization value defined in earlier papers as a number parameter of fluid dynamics. It indicates that the model with the loop correction boosts in explaining about the formation of QGP droplet in the expansion of early universe.

Kinetics driving nanocomposite thin-film deposition in low-pressure misty plasma processes

Mist-assisted methods have recently attracted much attention for plasma deposition in high-quality (multi)functional thin films. However, very little is known on plasma interactions with misted colloidal solutions and their role in plasma process kinetics. Time-resolved optical diagnostics have been carried out to study the deposition of TiO2–SiO2 nanocomposite thin films in low-pressure oxygen-argon plasmas with organosilicon precursors and TiO2 suspensions. Each pulsed injection of the dispersion was followed by a pressure rise due to solvent evaporation. This caused a significant reduction in the electron temperature and density, which mitigated matrix precursor fragmentation and SiO2 deposition as TiO2 nanoparticles were supplied to the film. Comparing injections with and without nanoparticles, misty plasma effects were dominated by plasma droplets rather than plasma-nanoparticle interactions. Successive matrix-rich and nanoparticle-rich deposition steps were confirmed by in situ spectroscopic ellipsometry.

Evolution of electro-induced blood plasma droplets on a superhydrophobic microstructured surface

Formation of severe adhesion on electrosurgical devices during their interaction with biofluids is an inherent problem that often causes reduced cutting efficiency and failed hemostasis. The introduction of (super-) hydrophobic surfaces is a favorable option for anti-adhesion, but the mechanisms related to their evolution with biofluids under electric fields are still not fully understood. Here, we investigated the evolution of blood plasma droplets on a superhydrophobic microstructured (SHM) surface under direct-current (DC) and alternating-current (AC) electric fields. The electrolysis of plasma droplets leads to the formation and diffusion of bubbles accompanied by a rise in temperature, while in turn, the electrolysis is suppressed as the bubbles fill the droplets, followed by a decrease in temperature. We show that under the DC electric field, the bubbles produced by papillae on the SHM surface can effectively prevent directional adsorption of plasma proteins compared to the flat surface, whereas the AC electric field induces oscillations in plasma proteins, resulting in even less adhesion. These findings provide valuable basic information for understanding the anti-adhesion mechanism of electrosurgical devices at a microscopic level.