Distinct Particle Research Articles

From Short-Range to Contact Interactions in Two-dimensional Many-Body Quantum Systems

Quantum systems composed of N distinct particles in mathbb {R}^2 with two-body contact interactions of TMS type are shown to arise as limits—in the norm resolvent sense—of Schrödinger operators with suitably rescaled pair potentials.

Characterizing Satellite Path Through Kelvin‐Helmholtz Instability Using a Mixing Parameter

AbstractWe introduce the mixing parameter to analyze the in situ measurements of a Kelvin‐Helmholtz event observed by the Magnetospheric Multiscale mission. We define the mixing parameter, for both ions and electrons, using the well distinct particle energies which characterize the magnetosphere and magnetosheath plasmas. This parameter nicely identifies the different populations which are interacting at the Earth's magnetopause and the boundaries of Kelvin‐Helmholtz vortices. Thus, we analyze the crossing of each structure into a parameter space defined as the space of the electron mixing versus the ion mixing, where specific shapes occur according to the evolutionary phase of the Kelvin‐Helmholtz instability. All along the event, we observe three different types of shapes, namely a straight line, a simple loop, and a complex loop, which likely corresponds to linear waves, steepened waves, and rolled‐up vortices, respectively. The most complex shape (rolled‐up vortex) is observed mostly at the end of the interval, owing to fast growth of the instability which is connected to variations of the solar wind magnetic field orientation.

Scavenging of Black Carbon Aerosols by Radiation Fog in Urban Central China

Radiation fog episodes are characterized by aerosol radiative properties measured at Hefei in urban central China, which hopefully benefits numerical weather prediction and air quality improvement for local governments. In this study, a high mean aerosol optical depth (AOD) is seen over Hefei during the sampling period, whereas an AOD of ~3.0 at 550 nm is observed during the fog episodes. We redefine the fog scavenging coefficient based on its starting and ending points in time, and a black carbon (BC) scavenging coefficient of 30% is observed. Meanwhile, the fog process cannot reduce aerosol number concentrations at size bins between 0.5 and 0.6 μm, whereas a mean particle scavenging coefficient of 21% at sizes within 0.6–1 μm is seen. Significantly large median aerosol scattering coefficient (2690 Mm−1) and absorption coefficient (446 Mm−1) at 550 nm, and low scattering Angstrom exponent in fog are observed, while distinctive particle size distributions between fog and haze are shown. Particle mean size distribution in fog is lower than that in haze at size bins between 0.7 and 2.1 μm, whereas the reverse is true for sizes within 0.5–0.7 μm and larger than 2.1 μm. Aerosol scattering during fog episodes undergoes a bigger increase than particle absorption, and this increase of scattering in fog is even higher than in haze. Median single scattering albedos of 0.86, 0.82, and 0.76 at 550 nm and aerosol radiative forcing efficiencies of −15.0, −14.0, and −10.0 W/m2 are seen for fog, haze and clear periods, respectively, and more negative radiative forcing efficiency emphasizes the significance of fog episodes on climate forcing. Our study clearly reveals the changes of aerosol radiative properties during radiation fog, particularly a synchronous variation of fog aerosol backscattering ratio with the visibility, indicating that more large particles are formed with fog becoming thicker and are scavenged with the dissipation of fog.

Influence of sulfurization time and Cu-ZnS-Sn stack order on the properties of thermally evaporated CZTS thin films

Cu2ZnSnS4 (CZTS) thin films were synthesized in a two-step procedure. Sulfurization of stacked thin films SLG/ZnS/Sn/Cu (S1) and SLG/Cu/Sn/ZnS (S2) after sequential deposition of Cu, ZnS, and Sn precursors was carried out. At 550 °C, two sulfurization periods were applied to both stack orders. Sample S1 sulfurized for 30 min (S1-T30) had a better crystallite size of roughly 50 nm, lower lattice strain, and lower dislocation density than other samples. The Cu/Zn cation ordering in the CZTS crystal system was significantly affected by stack sequence and sulfurization time, according to Q-factor calculation. The stack order of the S1 series allowed for homogenous and distinct particle development. From the elemental analysis, it is observed that the stack sequence and sulfurization used for sample S1-T30 permitted a near stoichiometric composition. The sample S1-T30 exhibited an optimal band gap value of 1.47 eV. To propose feasible alterations in the structural ordering, band gap calculations were used. In comparison to the stack order of the S2 series, the stack order SLG/ZnS/Sn/Cu with a sulfurization time of 30 min created a single-phase CZTS, implying less synthesis time to obtain an absorber quality CZTS layer for solar photovoltaic application.

Benchmarking a Microfluidic-Based Filtration for Isolating Biological Particles.

Isolating particles from complex fluids is a crucial approach in multiple fields including biomedicine. In particular, biological matrices contain a myriad of distinct particles with different sizes and structures. Extracellular vesicles (EVs), for instance, are nanosized particles carrying vital information from donor to recipient cells, and they have garnered significant impact on disease diagnostics, drug delivery, and theranostics applications. Among all the EV types, exosome particles are one of the smallest entities, sizing from 30 to 100 nm. Separating such small substances from a complex media such as tissue culture and serum is still one of the most challenging steps in this field. Membrane filtration is one of the convenient approaches for these operations; yet clogging, low-recovery, and high fouling are still major obstacles. In this study, we design a two-filter-integrated microfluidic device focusing on dead-end and cross-flow processes at the same time, thereby minimizing any interfering factors on the recovery. The design of this platform is also numerically assessed to understand pressure-drop and flow rate effects over the procedure. As a model, we isolate exosome particles from human embryonic kidney cells cultured in different conditions, which also mimic complex fluids such as serum. Moreover, by altering the flow direction, we refresh the membranes for minimizing clogging issues and benchmark the platform performance for multitime use. By comprehensively analyzing the design and operation parameters of this platform, we address the aforementioned existing barriers in the recovery, clogging, and fouling factors, thereby achieving the use of a microfluidic device multiple times for bio-nanoparticle isolation without any notable issues.

Frontispiece: Insights on Luminescent Micro‐ and Nanospheres of Infinite Coordination Polymers

Infinite coordination polymers (ICPs) are compounds similar to metal-organic frameworks (MOFs), but with distinct particle morphologies. Micro- or nanospheres of ICPs are the most reported, which are frequently synthesized by using rare-earth ions. This article covers the growth mechanisms of spherical ICP particles and the main applications related to luminescent properties, including chemical sensing, light emission, bioimaging and templating. Read more in the Minireview by R. C. G. Frem, G. Arroyos et al. on page 5 ff.

Experimental Assessment on the Internal Instability of Broadly Graded Silty Sand

Suffusion can occur when fine particles are under low effective stress and free to travel through constrictions between coarse particles, and sufficient seepage forces move the fine particles through the voids. Generally, gap-graded soils, which are a binary mixture of two distinct particle sizes, are susceptible to suffusion. Such soils show clear manifestations of suffusion, such as a significant quantity of fine particles discharged and an increase in permeability and void ratio. Therefore, in previous studies on seepage erosion problems, gap-graded soils were mostly utilized as the target soil. However, it is not clear whether the broadly graded soils, the fill dam materials in South Korea, are susceptible to suffusion according to the existing criteria and previous research. Additionally, experimental studies on broadly graded soils have rarely been conducted, especially in terms of hydraulic conditions. Therefore, a deeper understanding of the suffusion progress on broadly graded soils under various hydraulic conditions (hydraulic gradients) is required. In the present study, suffusion tests were performed on gap-graded andbroadly graded soils with different relative densities by using the newly developed suffusion test apparatus. During the test, the hydraulic gradient was increased stepwise, and the occurrence and progress of internal erosion were analyzed based on the amount of discharged soil and the coefficient of permeability. In contrast to gap-graded soils, the test results for broadly graded soils showed a continuous reduction in k before the initiation of erosion. At the onset of internal instability, sudden increases in k and soil discharge occurred under a relatively high hydraulic gradient. Additionally, a series of seepage tests on broadly graded soils showed that the higher the relative density, the higher the hydraulic gradient required to reach an unstable state.

Quantitative mining of compositional heterogeneity in cryo-EM datasets of ribosome assembly intermediates

Single-particle cryoelectron microscopy (cryo-EM) offers a unique opportunity to characterize macromolecular structural heterogeneity by virtue of its ability to place distinct particle populations into different groups through computational classification. However, there is a dearth of tools for surveying the heterogeneity landscape, quantitatively analyzing heterogeneous particle populations after classification, deciding how many unique classes are represented by the data, and accurately cross-comparing reconstructions. Here, we develop a workflow that contains discovery and analysis modules to quantitatively mine cryo-EM data for sets of structures with maximal diversity. This workflow was applied to a dataset of E.coli 50S ribosome assembly intermediates, which are characterized by significant structural heterogeneity. We identified more detailed branchpoints in the assembly process and characterized the interactions of an assembly factor with immature intermediates. While the tools described here were developed for ribosome assembly, they should be broadly applicable to the analysis of other heterogeneous cryo-EM datasets.

Targeted Synthesis of the Type-A Particle Substructure from Enzymatically Produced Eumelanin.

Eumelanin exhibits a defined supramolecular buildup that is deprived of at least three distinct particle species. To enable the full potential of its promising material properties, access to all particle types is crucial. In this work, the first protocol for the synthesis of the intermediate type-A particles in pure and stable dispersion form is described. It is found that aggregation of type-A particles into the larger type-B variant can be inhibited by a strict pH control during the synthesis. The exact influence of pH on the supramolecular buildup is investigated via a combination of time-resolved light scattering, electron microscopy, and UV–vis spectroscopy. It is observed that a rapid buildup of type-B particles occurs without pH control and is generally dominant at lower pH values. At pH values above 6.2 however, type-A particles are gained, and no further aggregation occurs. Even more, lowering the pH of such a stable type-A dispersion at a later stage lifts the inhibition and again leads to the formation of larger particle species. The results confirm that it is easily possible to halt the aggregation of eumelanin substructures and to access them in the form of a stable dispersion. Moreover, a profound additional understanding of the supramolecular buildup is gained by the in-depth investigation of the pH influence.

Flow and Melting Thermal Transfer Enhancement Analysis of Alumina, Titanium Oxide-Based Maxwell Nanofluid Flow Inside Double Rotating Disks with Finite-Element Simulation

The energy produced by the melting stretching disks surface has a wide range of commercial applications, including semi-conductor material preparation, magma solidification, permafrost melting, and frozen land refreezing, among others. In view of this, in the current communication we analyzed magnetohydrodynamic flow of Maxwell nanofluid between two parallel rotating disks. Nanofluids are important due to their astonishing properties in heat conduction flows and in the enhancement of electronic and manufacturing devices. Furthermore, the distinct tiny-sized particles and in the Maxwell water-based fluid for enhancing the heat transfer rate are analyzed. The heat equation is developed in the occurrence of thermal radiation. The influences of melting impacts are incorporated. The mathematical model is developed in the form of partial differential expressions then converted to ordinary differential equations by employing tool of similarity variables. Finite element method (FEM) is chosen for solving the nonlinear governing ordinary differential equations (ODEs) with necessary conditions. The consequence of flow parameters against the velocity profiles and heat transport field is considered. The noted novelty of this communication is to discuss the thermal transfer of Maxwell nanofluid model through double stretching disks with thermal radiation and melting phenomenon. Further, /water and /water are considered in the modeling.

A Statistical Evaluation of Uncoupling Protein 1 in the Limited Area of Brown Adipose Tissue by Immunoelectron Microscopy

Uncoupling protein 1 (UCP1) expressed by the brown adipose tissue (BAT) in the mitochondrial crista acts as a homeostatic thermogenerator of eutherians. The evaluation of UCP1 expression in the BAT offers significant scientific insight, especially in studies targeting limited areas such as the periarterial and pericardial regions of small experimental mammals. However, the negligible amount of this adipose tissue would render the general quantitative evaluation of the protein unreliable because of lipid contamination and low protein concentration. To address this problem, we quantitatively evaluated UCP1 expression in the mitochondrion of the mouse interscapular BAT using immunoelectron microscopy and immunohistochemical studies using a combination of primary and secondary antibodies in scheme A (rabbit anti-UCP1 IgG/gold particle-conjugated goat anti-rabbit IgG), B (rabbit IgG/gold particle-conjugated goat anti-rabbit IgG), C (rabbit anti-UCP1 IgG/gold particle-unconjugated goat anti-rabbit IgG), and D (rabbit IgG/gold particle-unconjugated goat anti-rabbit IgG). Scheme A shows the immunopositive reaction of obvious gold particles in the mitochondrial area, whereas other procedures revealed less distinctive reactions. The distinctive gold particle immunoreaction comprised electrical high-density spots with a mean diameter of >5 nm. However, in scheme B, the electrical high-density spots were scattered outside the mitochondrion and were significantly smaller than 4 nm; schemes C and D demonstrated few immunoreactions. Logistic regression analysis between schemes A and B showed that the threshold diameter of the electrical high-density spots measuring >5 nm indicated a true positive immunoreaction to anti-UCP1 antibody specifically in the mitochondrial area. Minor statistical difference was observed in the primary anti-UCP1 antibody between polyclonal IgG and monoclonal antibodies. Therefore, immunoelectron microscopy might be useful for evaluating negligible protein expression in some limited areas, such as UCP1 expression in the BAT of small experimental animals.

Equilibration and Locality

Experiments motivated by predictions of quantum mechanics indicate non-trivial correlations between spacelike-separated measurements. The phenomenon is referred to as a violation of strong-locality and, after Einstein, called ghostly action at a distance. An intriguing and previously unasked question is how the evolution of an assembly of particles to equilibrium-state relates to strong-locality. More specifically, whether, with this respect, indistinguishable particles differ from distinguishable ones. To address the question, we introduce a Markov-chain based framework over a finite set of microstates. For the first time, we formulate conditions needed to obey the particle transport- and strong-locality for indistinguishable particles. Models which obey transport-locality and lead to equilibrium-state are considered. We show that it is possible to construct models obeying and violating strong-locality both for indistinguishable particles and for distinguishable ones. However, we find that only for distinguishable particles strongly-local evolution to equilibrium is possible without breaking the microstate-symmetry. This is the strongest symmetry one can impose and leads to the shortest equilibration time. We hope that the results presented here may provide a new perspective on a violation of strong-locality, and the developed framework will help in future studies. Specifically they may help to interpret results on high-energy nuclear collisions indicating a fast equilibration of indistinguishable particles.

Experimental study on fire spread over discrete fuel bed-Part II: Combined effects of wind and packing ratio

This work experimentally investigates the fire spread of discrete fuels by using fuel beds of laser-cut cardboards in a wind tunnel. Two distinct particle ignition modes are identified: under lower wind speed and packing ratio, a part of the tilted flame front inside the fuel bed touched and ignited the fuel elements; under a higher wind speed or packing ratio, the flame trough intermittently impinged on and ignited the fuels. When the wind speed is lower than a critical value (1.5 m s−1 in this work), the rate of spread (ROS), varying with the packing ratio, has a weak dependence on the wind speed. When the wind speed exceeds the critical value, ROS decreases with the packing ratio, and the dimensionless ROS almost linearly increases with the wind speed. The optimal packing ratio decreases with the wind speed. The characteristic length (the distance the flame front spreads in the shallow fuel layer) increases with the wind speed for lower packing ratios (0.018–0.032 in this work), while it first fluctuates and then increases with the wind speed under higher packing ratios (0.054 in this work). The temporal surface and internal flow velocities strongly depend on whether a stable peak-and-valley structure is sustained, affected by the wind speed and packing ratio. Nevertheless, the internal flow velocity near the flame front increases under all conditions, enhancing the internal convective heating on the unburned fuel.

Low-Symmetry MOF-Based Patchy Colloids and Their Precise Linking via Site-Selective Liquid Bridging to Form Supra-Colloidal and Supra-Framework Architectures.

Colloids with surface patches (or patchy particles) can bind and assemble with directionality. However, the bonding between the usually high-symmetry, dome-shaped patches is not precise, as it cannot lock the exact position and orientation of the relevant particles. This issue prevents the assembly of well-defined colloidal superstructures by design. Herein, we introduce low-symmetry, metal-organic framework (MOF)-based patchy colloids, which feature a polyhedral matrix and flat hexagonal patches, along with anisotropic surfaces and compositions. Guided by the encoded shape/chemical information and mediated by a site-selective liquid-bridging interaction, the distinct patchy particles self-assemble into supra-colloidal (or supra-framework) structures with unprecedented precision. In this case, the valence, position, and orientation of the particles within assemblies are fully coordinated and precisely aligned. The dynamic nature of the liquid bridges also allows us to investigate the unique assembly kinetics. Our strategy not only defines new modes of colloidal bonding, but also provides a powerful means toward creating hierarchical and multi-component MOF materials.

Low‐Symmetry MOF‐Based Patchy Colloids and Their Precise Linking via Site‐Selective Liquid Bridging to Form Supra‐Colloidal and Supra‐Framework Architectures

AbstractColloids with surface patches (or patchy particles) can bind and assemble with directionality. However, the bonding between the usually high‐symmetry, dome‐shaped patches is not precise, as it cannot lock the exact position and orientation of the relevant particles. This issue prevents the assembly of well‐defined colloidal superstructures by design. Herein, we introduce low‐symmetry, metal–organic framework (MOF)‐based patchy colloids, which feature a polyhedral matrix and flat hexagonal patches, along with anisotropic surfaces and compositions. Guided by the encoded shape/chemical information and mediated by a site‐selective liquid‐bridging interaction, the distinct patchy particles self‐assemble into supra‐colloidal (or supra‐framework) structures with unprecedented precision. In this case, the valence, position, and orientation of the particles within assemblies are fully coordinated and precisely aligned. The dynamic nature of the liquid bridges also allows us to investigate the unique assembly kinetics. Our strategy not only defines new modes of colloidal bonding, but also provides a powerful means toward creating hierarchical and multi‐component MOF materials.

The Influence of the Symmetry of Identical Particles on Flight Times.

In this work, our purpose is to show how the symmetry of identical particles can influence the time evolution of free particles in the nonrelativistic and relativistic domains as well as in the scattering by a potential -barrier. For this goal, we consider a system of either two distinguishable or indistinguishable (bosons and fermions) particles. Two sets of initial conditions have been studied: different initial locations with the same momenta, and the same locations with different momenta. The flight time distribution of particles arriving at a ‘screen’ is calculated in each case from the density and flux. Fermions display broader distributions as compared with either distinguishable particles or bosons, leading to earlier and later arrivals for all the cases analyzed here. The symmetry of the wave function seems to speed up or slow down the propagation of particles. Due to the cross terms, certain initial conditions lead to bimodality in the fermionic case. Within the nonrelativistic domain, and when the short-time survival probability is analyzed, if the cross term becomes important, one finds that the decay of the overlap of fermions is faster than for distinguishable particles which in turn is faster than for bosons. These results are of interest in the short time limit since they imply that the well-known quantum Zeno effect would be stronger for bosons than for fermions. Fermions also arrive earlier and later than bosons when they are scattered by a -barrier. Although the particle symmetry does affect the mean tunneling flight time, in the limit of narrow in momentum initial Gaussian wave functions, the mean times are not affected by symmetry but tend to the phase time for distinguishable particles.

On number of particles in coalescing-fragmentating Wasserstein dynamics

We consider the system of sticky-reflected Brownian particles on the real line proposed in [4]. The model is a modification of the Howitt-Warren flow but now the diffusion rate of particles is inversely proportional to the mass which they transfer. It is known that the system consists of a finite number of distinct particles for almost all times. In this paper, we show that the system also admits an infinite number of distinct particles on a dense subset of the time interval if and only if the function responsible for the splitting of particles takes an infinite number of values.

MCMV Centrifugal Enhancement: A New Spin on an Old Topic.

Human cytomegalovirus (HCMV) is a ubiquitous pathogen infecting a majority of people worldwide, with diseases ranging from mild to life-threatening. Its clinical relevance in immunocompromised people and congenital infections have made treatment and vaccine development a top priority. Because of cytomegaloviruses’ species specificity, murine cytomegalovirus (MCMV) models have historically informed and advanced translational CMV therapies. Using the phenomenon of centrifugal enhancement, we explored differences between MCMVs derived in vitro and in vivo. We found centrifugal enhancement on tissue culture-derived virus (TCV) was ~3× greater compared with salivary gland derived virus (SGV). Using novel “flow virometry”, we found that TCV contained a distinct submicron particle composition compared to SGV. Using an inhibitor of exosome production, we show these submicron particles are not extracellular vesicles that contribute to centrifugal enhancement. We examined how these differences in submicron particles potentially contribute to differing centrifugal enhancement phenotypes, as well as broader in vivo vs. in vitro MCMV differences.

Justifying the classical partition function for bosonic and fermionic systems using computer based experiments

The partition function (PF) for a system of non-interacting N-particles can be found by summing over all the accessible states of the system. The PF for an ideal gas differs from bosonic or fermionic PF in the classical regime. Students find it difficult to follow the differences arising out of incorrect counting by the classical PF by missing out on the indistinguishability of particles and Fermi–Bose statistics. We present a pedagogical computer-based experiment to probe and demonstrate the key differences in the PFs (i) Q, for the system of distinguishable and indistinguishable particles (ii) B, for bosons and (iii) F, for fermions without formally using the single-particle PF.

Enhanced Breaking of Lignin and Mesopore Formation in Zinc Chloride Assisted Hydrothermal Carbonization of Waste Biomasses

Hydrochars from hydrothermal carbonization of different biowaste materials (dried dandelion, sawdust, coconut shell powder) formed in the presence of aqueous salt solutions were compared to those obtained by the common method in pure water. Hydrochars with increased carbon contents, pore volume and surface areas were specifically obtained from coconut shell powder in the presence of zinc chloride. Compositional and structural changes within the hydrochar products caused by the process conditions and/or the additive were characterized by solid state 13C NMR spectroscopy, proving that cellulose and, in particular, lignin units in the biomass are more easily attacked in the presence of the salt. Under saline conditions, a distinct particle break-up led to the creation of mesoporosity, as observable from hysteresis loops in nitrogen adsorption isotherms, which were indicative of the presence of pores with diameters of about 3 to 10 nm. The obtained hydrochars were still rich in functional groups which, together with the mesoporosity, indicates the compounds have a high potential for pollutant removal. This was documented by adsorption capacities for the methylene blue and methyl orange dyes, which exceeded the values obtained for other hydrochar-based adsorbers. A subsequent physical activation of the mesoporous hydrochars in steam at different temperatures and times resulted in a further drastic increase in the surface areas, of up to about 750 m2/g; however, this increase is mainly due to micropore formation coupled with a loss of surface functionality. Consequently, the adsorption capacity for the quite large dyes does not provide any further benefit, but the uptake of smaller gas molecules is favored.