Three-dimensional Confinement Research Articles

3D confinement alters smooth muscle cell responses to chemical and mechanical cues.

Smooth muscle cell (SMC) phenotypic switching is a hallmark of many vascular diseases. Although prior work has established that chemical and mechanical cues contribute to SMC phenotypic switching, the impact of three-dimensional (3D) confinement on this process remains elusive. Yet, in vivo, arterial SMCs reside within confined environments. In this study, we designed a microfluidic assay to investigate the interplay between 3D confinement and different environmental stimuli in SMC function. Our results show that tightly, but not moderately, confined SMCs acquire a contractile phenotype when exposed to collagen I. Elevated compressive forces induced by hydrostatic pressure abolish this upregulation of the contractile phenotype and compromise SMC survival, particularly in tightly confined spaces. Transforming growth factor beta 1, which promotes the contractile state in moderate confinement, fails to enhance the contractility of tightly confined cells. Fibronectin and engagement of cadherin 2 suppress the contractile phenotype of SMCs regardless of the degree of confinement. In contrast, homophilic engagement of cadherin 11 upregulates SMC-specific genes and enhances contractility in both moderately and tightly confined cells. Overall, our work introduces 3D confinement as a regulator of SMC phenotypic responses to chemical and mechanical signals.

Crystallization-dictated assembly of block copolymers and nanoparticles under three-dimensional confinement.

Crystallization-dictated self-assembly of crystalline block copolymers (BCPs) in solution has been utilized to produce many impressive nanostructures. However, when the assembly of crystalline BCPs happens in a three-dimensional (3D) confined space, predicting the self-assembly structure of BCPs becomes challenging due to the competition between crystallization and microphase separation. In this feature article, we summarize the recent progress in the self-assembly of crystalline BCPs under confinement, emphasizing the impact of crystallization behavior on the assembly structure. Furthermore, we highlight the crystallization-directed assembly of inorganic nanoparticles (NPs), either by pre-assembling crystalline polymers as templates or using crystalline polymer chain segments as ligands. By exploring the impact of crystallization behavior on the assembled structure of BCPs and NPs, it is helpful to predict and manipulate the properties of polymer/nanoparticle composites, thereby enabling the precise design of polymer metamaterials.

The linear Paul Trap's Confined Stability Area for 40Ca+ Ions

تقدم تكنولوجيا الكم طرقًا حسابية واتصالات ومحاكاة وقياسًا جديدة. تحتاج أجهزة الكمبيوتر التقليدية إلى المساعدة في حل المشكلات المهمة مثل التحليل بسبب الزيادات الهائلة في وقت الحساب. ومع ذلك، تستخدم أجهزة الكمبيوتر الكمومية ميكانيكا الكم لحجم المشكلة الأسي الفرعي ويمكنها محاكاة الطبيعة على المستوى الكمي. يهتم العلماء بشكل متزايد بتطوير أجهزة الكمبيوتر الكمومية باستخدام ذرات متأينة مفردة في مصائد باولي. تمثل الحالة الأساسية لكل أيون أقل قيمة ممكنة للبت الكمي. تم استخدام الأيونات المحتجزة 40Ca+ في إحدى الدراسات كمثال على الكيوبت الكمومي. تم استخدام برنامج MATLAB على العوامل النموذجية التي تؤثر على الحالة المقيدة وتأثيراتها. يجب أن تكون الحلول مستقرة في كلا الاتجاهين، مما يتطلب حصرًا ثلاثي الأبعاد لمعادلة ماثيو. تؤثر المتغيرات على المسافة من مركز المصيدة لنهاية القطب، وجهد UDC، وكتلة الأيون، والترددات الراديوية. تم استخدام جهد متغير للتحكم وإظهار تأثيره على سلسلة محددة من الأيونات المحاصرة. يهدف هذا البحث إلى فهم أفضل للظروف المثلى للحجز وحركة الأيونات من الحالة (4S1/2) إلى الحالة (4P1/2) بالرنين. تخضع الحالة الكمومية للتعديل والتغيير، مما يجعلها أداة واعدة لحل المشكلات المعقدة.

Synergistic Steric Effect of Precursor And Antisolvent Enables Strongly Confined Perovskite Films with Efficient and Spectral Stable Blue Emission.

Reducing the crystal size of perovskites to the strong quantum confinement regime is an effective way to realize blue luminescence for light-emitting applications. However, challenges remain in directly constraining the crystal growth during film preparation to achieve three-dimensional quantum confinement, and the widely used long-chain ligands may bring difficulties for charge transport and unfavorably affect the device performance. Herein, we report a novel strategy for fabricating strongly confined blue-emitting perovskite nanocrystalline films via synergistic steric effect modulation by precursors and antisolvents. We synthesize cesium pentafluoropropanoate (CsPFPA) as a new type of precursor agent, where the steric effect of the PFPA group can help constrain the growth of perovskite crystals and passivate the defects. Furthermore, different types of antisolvents with varied molecular sizes and steric hindrance are used to regulate the size of perovskite crystals and improve film quality. Consequently, highly emissive blue perovskite films are realized with the emission wavelength effectively tuned in the blue region by varying the concentration of CsPFPA as well as the type of antisolvents. Based on the strongly confined perovskite films, blue light-emitting diodes (LEDs) are constructed, showing good spectral tunability and stability in the electroluminescence. This work demonstrates a novel pathway for developing bright perovskite blue emitters for LEDs, which may potentially advance their future applications in display and lighting.

Transverse-momentum-dependent gluon distributions of proton within basis light-front quantization

Gluon transverse-momentum dependent distributions (TMDs) are very important for revealing the internal structure of the proton. They correspond to a variety of experiments and are among the major tasks of the future electron-ion colliders. In this paper, we calculate the T-even gluon TMDs at the leading twist within the Basis Light-front Quantization framework. We employ the light-front wave functions of the proton obtained from a light-front quantized Hamiltonian with Quantum Chromodynamics input determined for its valence Fock-sector with three constituent quarks and an additional Fock-sector, encompassing three quarks and a dynamical gluon, with a three-dimensional confinement. After obtaining the numerical results we investigate the properties of gluon TMDs by checking whether they satisfy the Mulders-Rodrigues inequalities and investigate the correlations between transverse and longitudinal degrees of freedom. With their connection to unintegrated gluon distributions in mind, we further investigate the limiting behaviors of gluon TMDs in the small-x and large-x regions.

High-capacity K+-pillared layered manganese dioxide as cathode material for high-rate aqueous zinc-ion battery

Sluggish kinetics and severe structural instability of manganese-based cathode materials for rechargeable aqueous zinc-ion batteries (ZIBs) lead to low-rate capacity and poor cyclability, which hinder their practical applications. Pillaring manganese dioxide (MnO2) by pre-intercalation is an effective strategy to solve the above problems. However, increasing the pre-intercalation content to realize stable cycling of high capacity at large current densities is still challenging. Here, high-rate aqueous Zn2+ storage is realized by a high-capacity K+-pillared multi-nanochannel MnO2 cathode with 1 K per 4 Mn (δ-K0.25MnO2). The high content of the K+ pillar, in conjunction with the three-dimensional confinement effect and size effect, promotes the stability and electron transport of multi-nanochannel layered MnO2 in the ion insertion/removal process during cycling, accelerating and accommodating more Zn2+ diffusion. Multi-perspective in/ex-situ characterizations conclude that the energy storage mechanism is the Zn2+/H+ ions co-intercalating and phase transformation process. More specifically, the δ-K0.25MnO2 nanospheres cathode delivers an ultrahigh reversible capacity of 297 mAh g−1 at 1 A g−1 for 500 cycles, showing over 96 % utilization of the theoretical capacity of δ-MnO2. Even at 3 A g−1, it also delivered a 63 % utilization and 64 % capacity retention after 1000 cycles. This study introduces a highly efficient cathode material based on manganese oxide and a comprehensive analysis of its structural dynamics. These findings have the potential to improve energy storage capabilities in ZIBs significantly.

Skewed generalized parton distributions of proton from basis light-front quantization

We obtain all the leading-twist quark generalized parton distributions (GPDs) inside the proton at nonzero skewness within the basis light-front quantization framework. We employ the light-front wave functions of the proton from a light-front quantized Hamiltonian in the valence Fock sector consisting of a three-dimensional confinement potential and a one-gluon exchange interaction with fixed coupling. We find that the qualitative behaviors of our GPDs are similar to those of other theoretical calculations. We further examine the GPDs within the boost-invariant longitudinal coordinate, σ=12b−P+, which is identified as the Fourier conjugate of the skewness. The GPDs in the σ-space show diffraction patterns, which are akin to the diffractive scattering of a wave in optics.

Viscoelastic property enhancement of polymethylmethacrylate molecularly confined within 3D nanostructures

Owing to its applications in various fields, such as biomedical, microelectronics, sensors, and polymer composites, polymer nanoconfinement is a widely studied topic. This confinement changes the configuration of molecules compared with those of solids, which, in the case of polymeric films, decreases the glass transition temperature and mechanical properties of the polymer. In this study, nanostructured polymethylmethacrylate, presenting three-dimensional nanoscale confinement were evaluated using amplitude modulation–frequency modulation atomic force microscopy for the first time. The Young’s moduli and loss tangents were measured, and the results suggest that for cells smaller than approximately 39 nm, the Young’s modulus of the 3-D confined polymer enhances that of the raw solid owing to reduced molecular mobility. This research shows that the molecular mobility was reduced because polymer chains were confined within three-dimensional space.

Quark and gluon distributions in ρ-meson from basis light-front quantization

We solve for the ρ-meson's wave functions from a light-front QCD Hamiltonian determined for its constituent quark-antiquark and quark-antiquark-gluon Fock components, with a three-dimensional confinement using basis light-front quantization. From this, we obtain the leading-twist valence quark's parton distribution functions and transverse momentum-dependent parton distributions inside the ρ-meson. These results are qualitatively consistent with those of other models. We also demonstrate the important effects of a dynamical gluon on the ρ-meson's gluon densities, helicity, transversity, and tensor polarized distributions.

High Q-Factor Single-Mode Lasing in Inorganic Perovskite Microcavities with Microfocusing Field Confinement.

The realization of high-Q single-mode lasing on the microscale is significant for the advancement of on-chip integrated light sources. It remains a challenging trade-off between Q-factor enhancement and light-field localization to raise the lasing emission rate. Here, we fabricated a zero-dimensional perovskite microcavity integrated with a nondamage pressed microlens to three-dimensionally tailor the intracavity light field and demonstrated linearly and nonlinearly (two-photon) pumped lasing by this microfocusing configuration. Notably, the microlensing microcavity experimentally achieves a high Q-factor (16700), high polarization (99.6%), and high Purcell factor (11.40) single-mode lasing under high-repetition pulse pumping. Three-dimensional light-field confinement formed by the microlens and plate microcavity simultaneously reduces the mode volume (∼3.66 μm3) and suppresses diffraction and transverse walk-off loss, which induces discretization on energy-momentum dispersions and spatial electromagnetic-field distributions. The Q factor and Purcell factor of our lasing come out on top among most of the reported perovskite microcavities, paving a promising avenue toward further studying electrically driven on-chip microlasers.

Rehabilitation of rail track facing cross-level issues using polymeric geocell

One of the issues with the existing rail network is the cross-level issue, where the two parallel tracks have unwanted elevation differences, risking train derailment. The speed of trains is typically reduced in those identified areas but still, the geometric irregularity causes train body vibrations reduces the riding comfort. Once that elevation difference exceeds a design limit operation ceases for safety. Conventional solutions to this are jacking up the track by re-filling material inside and injecting expandable foam. None of those temporary techniques have a significant contribution to eliminating the root cause; rather invite additional risks with unpredictable differential stiffness. An enduring solution is rebuilding the embankment with the use of strong geocell reinforcement. The threedimensional confinement along with the high tensile strength of reinforcing polymeric geocell introduces a stiffer layer. Through this paper, a design approach utilizing the tensile strength, stiffness, and geometric properties of the geocell has been established to provide a dependable solution. Three projects have been discussed where a high-strength novel polymeric alloy geocell with the established design method was successfully used. The effective theoretical reduction of bearing pressure was from 38% to 55%. Observation over a year indicated the effectiveness of the design methodology.

Phase behavior of symmetric diblock copolymers under 3D soft confinement.

The phase behavior of symmetric diblock copolymers under three-dimensional (3D) soft confinement is investigated using self-consistent field theory. Soft confinement is realized in binary blends composed of AB diblock copolymers and C homopolymers, where the copolymers self-assemble to form a droplet embedded in a homopolymer matrix. The phase behavior of the confined block copolymers is regulated by the degree of confinement and the selectivity of the homopolymers, resulting in a rich variety of novel structures. When the C homopolymers are neutral to the A- and B-blocks, stacked lamellae (SL) are formed where the number of layers increases with the droplet volume, resulting in a morphological transition sequence from Janus particles to square SL. When the C homopolymers are strongly selective for the B-blocks, a series of non-lamellar morphologies, including onion-, hamburger-, cross-, ring-, and cookie-like structures, are observed. A detailed free energy analysis reveals a first-order reversible transformation between SL and onion-like (OL) structures when the selectivity of the homopolymers is changed. Our results provide a comprehensive understanding of how various factors, such as the copolymer concentration, homopolymer chain length, degree of confinement, and homopolymer selectivity, affect the self-assembled structures of diblock copolymers under soft 3D confinement.

Li2C2O4 with 3D confinement as simultaneous sacrificial material and activation reagent of biomass-derived carbon for advanced lithium-ion capacitors

Inappropriate pore size distribution and the lack of a suitable lithium-cation source in the device are the key issues limiting the industrial application of biowaste carbon-based lithium-ion capacitors (LICs) to achieve both high energy density and power density for energy storage. Herein, the Li2O nanowires, decomposed from Li2C2O4 under three-dimensional confinement provided by wasted feather-derived carbon, are introduced as a sacrificial material for self-prelithiation activated carbon materials (prAC) cathode preparation with a high practical specific capacity of 1376 mAh/g. Accompanied by the in-situ formation of Li2O, the volume of mesopores increases significantly to 0.319 cm3/g (32.1 vol% of the total pore volume) by activation with CO2 yielded by the decomposition of Li2C2O4. The assembled prAC/graphite LIC demonstrates a high energy density of (122 Wh/kg at 220 W/kg) and a high power density (13 kW/kg at 30 Wh/kg), as well as a superior lifespan of 10,000 cycles at 1 A/g.

Development of a High Sampling Rate Data Acquisition System Working in a High Pulse Count Rate Region for Radiation Diagnostics in Nuclear Fusion Plasma Research

In this study, a high sampling rate data acquisition system with the ability to provide timestamp, pulse shape information, and waveform simultaneously under a sub megahertz pulse counting rate was developed for radiation diagnostics for magnetic confinement nuclear fusion plasma research. The testing of the data acquisition system under the high pulse counting rate condition using real signals was performed in an accelerator-based deuterium-deuterium fusion neutron source (Fast Neutron Source) at the Japan Atomic Energy Agency. We found that the pulse counts acquired by the system linearly increased up to 6 × 105 cps, and the count loss at 106 cps was estimated to be ~10%. The data acquisition system was applied to deuterium-deuterium neutron profile diagnostics in the deuterium gas operation of a helical-type magnetic confinement plasma device, called the Large Helical Device, to observe the radial profile of neutron emissivity for the first time in a three-dimensional magnetic confinement fusion device. Time-resolved measurements of the deuterium-deuterium fusion emission profile were performed. The experimentally observed radial neutron emission profile was consistent with numerical predictions based on the orbit-following models using experimental data. The data acquisition system was shown to have the desired performance.

(Al, Ga)N-Based Quantum Dots Heterostructures on h-BN for UV-C Emission.

Aluminium Gallium Nitride (AlyGa1-yN) quantum dots (QDs) with thin sub-µm AlxGa1-xN layers (with x > y) were grown by molecular beam epitaxy on 3 nm and 6 nm thick hexagonal boron nitride (h-BN) initially deposited on c-sapphire substrates. An AlN layer was grown on h-BN and the surface roughness was investigated by atomic force microscopy for different deposited thicknesses. It was shown that for thicker AlN layers (i.e., 200 nm), the surface roughness can be reduced and hence a better surface morphology is obtained. Next, AlyGa1-yN QDs embedded in Al0.7Ga0.3N cladding layers were grown on the AlN and investigated by atomic force microscopy. Furthermore, X-ray diffraction measurements were conducted to assess the crystalline quality of the AlGaN/AlN layers and examine the impact of h-BN on the subsequent layers. Next, the QDs emission properties were studied by photoluminescence and an emission in the deep ultra-violet, i.e., in the 275-280 nm range was obtained at room temperature. Finally, temperature-dependent photoluminescence was performed. A limited decrease in the emission intensity of the QDs with increasing temperatures was observed as a result of the three-dimensional confinement of carriers in the QDs.

Temperature/pH dual-responsive reversible morphology evolution of block copolymer microparticles under three-dimensional confinement

Temperature/pH dual-responsive reversible morphology evolution of block copolymer microparticles under three-dimensional confinement

Axial Dual Atomic Sites Confined by Layer Stacking for Electroreduction of CO2 to Tunable Syngas.

Arranging atoms in an orderly manner at the atomic scale to create stable polyatomic structures is a very challenging task. In this study, we have developed three-dimensional confinement areas on the two-dimensional surface by creating regional defects. These areas are composed of vertically stacked graphene layers, where Ni and Fe atoms are anchored concentrically to form axial dual atomic sites in high yield. These sites can be used to produce tunable syngas through the electroreduction of CO2. Theoretical calculations indicate that the Ni sites vertically regulate the charge distribution of the adjacent Fe sites in the layer below, resulting in a lower d-band center. This, in turn, weakens the adsorption of the *CO intermediate and inhibits the production of H2 at the Fe site. Our research presents a novel approach for concentrated creation of dual atomic sites by building a confinement-selective surface.

Modeling and Simulation of Linear Triblock Copolymers under Three-Dimensional Confinement

Modeling and Simulation of Linear Triblock Copolymers under Three-Dimensional Confinement

Appropriate Mechanical Confinement Inhibits Multipolar Cell Division via Pole-Cortex Interaction

Multipolar spindles are very rare in normal tissues, but they are much more prevalent in many tumors, which might be induced by the mechanical confinements from overcrowding microenvironments in tumors. However, little is known about what the difference is between various forms of mechanical confinements that cells encounter in normal tissues and tumor tissues, and how they affect multipolarity and chromosome segregation fidelity. Here, we use microchannels with different heights and widths to mimic diverse forms and degrees of mechanical constraints within the tissue architecture. We find that multipolar spindles occur frequently under two-wall confinement but that they are rare under four-wall confinement, suggesting that multipolar-spindle assembly depends on the form of the three-dimensional mechanical confinement. We reveal that two-wall confinement leads to an increased fraction of multipolar spindles by pole splitting, while four-wall confinement restrains multipolarity by the enhancement of pole clustering and the inhibition of pole splitting. We further conduct numerical simulations and develop a theoretical model to investigate how mechanical confinement influences pole splitting and clustering. By exploring the energy landscape of pole-pole interactions and pole-cortex interactions and treating pole splitting and clustering as reversible reactions, we demonstrate that mechanical confinement controls cell shape and pole-cortex interactions, which, in turn, change the energy barriers of pole splitting and clustering as well as the probability of multipolar mitosis. Further experiments confirm the theoretical prediction that the pole-cortex interaction determines the probability of the multipolar spindles under various mechanical confinements. Our findings demonstrate the extent to which extracellular microenvironments and tissue architecture can affect complex cellular behaviors, indicating that normal tissue architecture may have the ability to suppress the progress of cancers. Thus, our findings would provide essential cues for cancer therapies targeting the tumor microenvironment.6 MoreReceived 15 March 2022Revised 30 November 2022Accepted 26 January 2023DOI:https://doi.org/10.1103/PhysRevX.13.011036Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBiomechanicsCell divisionMitosisPhysical SystemsChromosomesMicrotubulesTechniquesConfocal imagingFluorescence spectroscopyMonte Carlo methodsBiological Physics

Transverse structure of the pion beyond leading twist with basis light-front quantization

We investigate the twist-3 transverse-momentum-dependent parton distribution functions (TMDs) of the pion with basis light-front quantization. The twist-3 TMDs are not independent and can be decomposed into twist-2 and genuine twist-3 terms from the equations of motion (EOM). We compute the TMDs from the resulting light-front wave functions obtained by diagonalizing the light-front QCD Hamiltonian, determined for pion's constituent quark-antiquark and quark-antiquark-gluon Fock sectors, with three-dimensional confinement. We also obtain the twist-3 parton distribution functions (PDFs) and show that they preserve the sum rule, which affirms the robustness of our approach. This is the first time that theoretical predictions are made for subleading twist structures of the pion containing interference terms between two light-front Fock sectors.