Structural insights into human EMC and its interaction with VDAC.

The endoplasmic reticulum (ER) membrane protein complex (EMC) is a conserved, multi-subunit complex acting as an insertase at the ER membrane. Growing evidence shows that the EMC is also involved in stabilizing and trafficking membrane proteins. However, the structural basis and regulation of its multifunctionality remain elusive. Here, we report cryo-electron microscopy structures of human EMC in apo- and voltage-dependent anion channel (VDAC)-bound states at resolutions of 3.47 Å and 3.32 Å, respectively. We discovered a specific interaction between VDAC proteins and the EMC at mitochondria-ER contact sites, which is conserved from yeast to humans. Moreover, we identified a gating plug located inside the EMC hydrophilic vestibule, the substrate-binding pocket for client insertion. Conformation changes of this gating plug during the apo-to-VDAC-bound transition reveal that the EMC unlikely acts as an insertase in the VDAC1-bound state. Based on the data analysis, the gating plug may regulate EMC functions by modifying the hydrophilic vestibule in different states. Our discovery offers valuable insights into the structural basis of EMC's multifunctionality.

CFM-YOLOv5:CFPNet moudle and muti-target prediction head incorporating YOLOv5 for metal surface defect detection.

Aiming at the problem of low efficiency of manual detection in the field of metal surface defect detection, a deep learning defect detection method based on improved YOLOv5 algorithm is proposed. Firstly, in the feature enhancement part, we replace the multi-head self-attention module of the standard transformer encoder with the EVC module to improve the feature extraction ability. Second, in the prediction part, adding a small target detection head can reduce the negative impact of drastic object scale changes and improve the accuracy and stability of detection. Finally, the performance of the algorithm is verified by ablation experiments and analogy experiments. The experimental results show that the improved algorithm has greatly improved mAP and FPS on the data set, and can quickly and accurately identify the types of metal surface defects, which has reference significance for practical industrial applications.

Research on oil boom performance based on Smoothed Particle Hydrodynamics method.

To address the issues of fluid-solid coupling, instability in the liquid two-phase flow, poor computational efficiency, treating the free surface as a slip wall, and neglecting the movement of oil booms in simulating oil spill containment, this study adopts the Smoothed Particle Hydrodynamics (SPH) method to establish a numerical model for solid-liquid coupling and liquid two-phase flow, specifically designed for oil boom containment and control. The DualSPHysics solver is employed for numerical simulations, incorporating optimized SPH techniques and eight different skirt configurations of the oil boom into the numerical model of two-phase liquid interaction. By setting relevant parameters in the SPH code to enhance computational efficiency, the variations in centroid, undulation, and stability of undulation velocity for different oil boom shapes are observed. The experimental results demonstrate that the improved oil boom exhibits superior oil containment performance. These findings provide a theoretical basis for the design of oil boom skirt structures.

The development of cobalt phosphide co-catalysts on BiVO4 photoanodes to improve H2O2 production.

Photoanodic hydrogen peroxide (H2O2) production via water oxidation is limited by low yields and poor selectivity. Herein, four variations of cobalt phosphides, including pristine CoP and Co2P crystals, and two mixed-phase cobalt phosphides (CoP/Co2P) with different ratios, were applied as co-catalysts on the BiVO4 (BVO) photoanode to improve H2O2 production. The optimal yield and selectivity were approximately 9.6 µmol‧h-1‧cm-2 and 25.2 % at a voltage bias of 1.7 V vs reversible hydrogen electrode (VRHE) under sunlight illumination, respectively. This performance is approximately 1.8 times that of pristine BVO photoanode. The roles of the Co and P sites were investigated. In particular, the Co site promotes the breaking of one HO bond in water to form OH• radicals, which is the rate-determining step in H2O2 production. The P site plays an important role in the desorption of H2O2 formed from the catalyst, which is responsible for the recovery of fresh catalytic sites. Among the four samples, Co2P exhibited the best performance for H2O2 production because it had the highest rate of OH• formation owing to its improved accumulation property. This study offers a rational design strategy for co-catalysts for photoanodic H2O2 production.

Superconducting Cavity Electromechanics: The Realization of an Acoustic Frequency Comb at Microwave Frequencies.

We present a nonlinear multimode superconducting electroacoustic system, where the interplay between superconducting kinetic inductance and piezoelectric strong coupling establishes an effective Kerr nonlinearity among multiple acoustic modes at 10 GHz that could hardly be achieved via intrinsic mechanical nonlinearity. By exciting this multimode Kerr system with a single microwave tone, we further demonstrate a coherent electroacoustic frequency comb and provide theoretical understanding of multimode nonlinear interaction in the superstrong coupling limit. This nonlinear superconducting electroacoustic system sheds light on the active control of multimode resonator systems and offers an enabling platform for the dynamic study of microcombs at microwave frequencies.

Sustainable photoanodes for water oxidation reactions: from metal-based to metal-free materials.

Sunlight affords an inexhaustible and primary energy for Earth. A photoelectrochemical system can efficiently harvest solar energy and convert it into chemicals. However, sophisticated processes and expensive raw materials are critical to restrict its further development. In recent years, the research focus of the PEC system has gradually shifted from traditional metal-based materials to earth-abundant metal-free materials. In this feature article, the photoanode materials for water oxidation reactions have been focused upon. The discussions on metal-based materials mainly include TiO2, BiVO4, and Ta3N5, and the examples for metal-free photoanodes are mainly polymeric carbon nitride and carbon doped boron nitride. This review offers opportunities for the further development of sustainable and cost-effective materials for the rational design of photoanodes for water oxidation reactions.

Bidirectional interconversion of microwave and light with thin-film lithium niobate.

Superconducting cavity electro-optics presents a promising route to coherently convert microwave and optical photons and distribute quantum entanglement between superconducting circuits over long-distance. Strong Pockels nonlinearity and high-performance optical cavity are the prerequisites for high conversion efficiency. Thin-film lithium niobate (TFLN) offers these desired characteristics. Despite significant recent progresses, only unidirectional conversion with efficiencies on the order of 10-5 has been realized. In this article, we demonstrate the bidirectional electro-optic conversion in TFLN-superconductor hybrid system, with conversion efficiency improved by more than three orders of magnitude. Our air-clad device architecture boosts the sustainable intracavity pump power at cryogenic temperatures by suppressing the prominent photorefractive effect that limits cryogenic performance of TFLN, and reaches an efficiency of 1.02% (internal efficiency of 15.2%). This work firmly establishes the TFLN-superconductor hybrid EO system as a highly competitive transduction platform for future quantum network applications.

Photonic integration of Er3+:Y2SiO5 with thin-film lithium niobate by flip chip bonding.

Rare earth ions are known as promising candidates for building quantum light-matter interface. However, tunable photonic cavity access to rare earth ions in their desired host crystal remains challenging. Here, we demonstrate the integration of erbium doped yttrium orthosilicate (Er3+:Y2SiO5) with thin-film lithium niobate photonic circuit by plasma-activated direct flip chip bonding. Resonant coupling to erbium ions is realized by on-chip electro-optically tuned high Q lithium niobate micro-ring resonators. Fluorescence and absorption of erbium ions at 1536.48 nm are measured in the waveguides, while the collective ion-cavity cooperativity with micro-ring resonators is assessed to be 0.36. This work presents a versatile scheme for future rare earth ion integrated quantum devices.

Mitigating photorefractive effect in thin-film lithium niobate microring resonators.

Thin-film lithium niobate is an attractive integrated photonics platform due to its low optical loss and favorable optical nonlinear and electro-optic properties. However, in applications such as second harmonic generation, frequency comb generation, and microwave-to-optics conversion, the device performance is strongly impeded by the photorefractive effect inherent in thin-film lithium niobate. In this paper, we show that the dielectric cladding on a lithium niobate microring resonator has a significant influence on the photorefractive effect. By removing the dielectric cladding layer, the photorefractive effect in lithium niobate ring resonators can be effectively mitigated. Our work presents a reliable approach to control the photorefractive effect on thin-film lithium niobate and will further advance the performance of integrated classical and quantum photonic devices based on thin-film lithium niobate.

Stable tuning of photorefractive microcavities using an auxiliary laser.

Cavity nonlinear optics enables intriguing physical phenomena to occur at micro- or nano-scales with modest input powers. While this enhances capabilities in applications such as comb generation, frequency conversion, and quantum optics, undesired nonlinear effects including photorefraction and thermal bistability are exacerbated. In this Letter, we propose and demonstrate a highly effective method of achieving cavity stabilization using an auxiliary laser for controlling photorefraction in a z-cut periodically poled lithium niobate (LN) microcavity system. Our numerical study accurately models the photorefractive effect under high input powers, guiding future analyses and development of LN microcavity systems.

Photorefraction-induced Bragg scattering in cryogenic lithium niobate ring resonators.

We report intracavity Bragg scattering induced by the photorefractive (PR) effect in high-Q lithium niobate ring resonators at cryogenic temperatures. We show that when a cavity mode is strongly excited, the PR effect imprints a long-lived periodic space-charge field. This residual field in turn creates a refractive index modulation pattern that dramatically enhances the back scattering of an incoming probe light, and results in selective and reconfigurable mode splittings. This PR-induced Bragg scattering effect, despite being undesired for many applications, could be utilized to enable optically programmable photonic components.

Quantum electronic control on chemical activation of methane by collision with spin-orbit state selected vanadium cation.

By coupling a newly developed quantum-electronic-state-selected supersonically cooled vanadium cation (V+) beam source with a double quadrupole-double octopole (DQDO) ion-molecule reaction apparatus, we have investigated detailed absolute integral cross sections (σ's) for the reactions, V+[a5DJ (J = 0, 2), a5FJ (J = 1, 2), and a3FJ (J = 2, 3)] + CH4, covering the center-of-mass collision energy range of Ecm = 0.1-10.0 eV. Three product channels, VH+ + CH3, VCH2+ + H2, and VCH3+ + H, are unambiguously identified based on Ecm-threshold measurements. No J-dependences for the σ curves (σ versus Ecm plots) of individual electronic states are discernible, which may indicate that the spin-orbit coupling is weak and has little effect on chemical reactivity. For all three product channels, the maximum σ values for the triplet a3FJ state [σ(a3FJ)] are found to be more than ten times larger than those for the quintet σ(a5DJ) and σ(a5FJ) states, showing that a reaction mechanism favoring the conservation of total electron spin. Without performing a detailed theoretical study, we have tentatively interpreted that a weak quintet-to-triplet spin crossing is operative for the activation reaction. The σ(a5D0, a5F1, and a3F2) measurements for the VH+, VCH2+, and VCH3+ product ion channels along with accounting of the kinetic energy distribution due to the thermal broadening effect for CH4 have allowed the determination of the 0 K bond dissociation energies: D0(V+-H) = 2.02 (0.05) eV, D0(V+-CH2) = 3.40 (0.07) eV, and D0(V+-CH3) = 2.07 (0.09) eV. Detailed branching ratios of product ion channels for the titled reaction have also been reported. Excellent simulations of the σ curves obtained previously for V+ generated by surface ionization at 1800-2200 K can be achieved by the linear combination of the σ(a5DJ, a5FJ, and a3FJ) curves weighted by the corresponding Boltzmann populations of the electronic states. In addition to serving as a strong validation of the thermal equilibrium assumption for the populations of the V+ electronic states in the hot filament ionization source, the agreement between these results also confirmed that the V+(a5DJ, a5FJ, and a3FJ) states prepared in this experiment are in single spin-orbit states with 100% purity.

Photonic Dissipation Control for Kerr Soliton Generation in Strongly Raman-Active Media.

Microcavity solitons enable miniaturized coherent frequency comb sources. However, the formation of microcavity solitons can be disrupted by stimulated Raman scattering, particularly in the emerging crystalline microcomb materials with high Raman gain. Here, we propose and implement dissipation control-tailoring the energy dissipation of selected cavity modes-to purposely raise or lower the threshold of Raman lasing in a strongly Raman-active lithium niobate microring resonator and realize on-demand soliton mode locking or Raman lasing. Numerical simulations are carried out to confirm our analyses and agree well with experiment results. Our work demonstrates an effective approach to address strong stimulated Raman scattering for microcavity soliton generation.

Chemical Activation of Water Molecule by Collision with Spin-Orbit-State-Selected Vanadium Cation: Quantum-Electronic-State Control of Chemical Reactivity.

We have obtained absolute integral cross sections (σ's) for the reactions of spin-orbit-state-selected vanadium cations, V+[a5DJ(J = 0, 2), a5FJ(J = 1, 2), and a3FJ(J = 2, 3)], with a water molecule (H2O) in the center-of-mass collision energy range Ecm = 0.1-10.0 eV. On the basis of these state-selected σ curves (σ versus Ecm plots) observed, three reaction product channels, VO+ + H2, VH+ + OH, and VOH+ + H, from the V+ + H2O reaction are unambiguously identified. Contrary to the previous guided ion beam study of the V+(a5DJ) + D2O reaction, we have observed the formation of the VO+ + H2 channel from the V+(a5DJ) + H2O ground reactant state at low Ecm's (<3.0 eV). No spin-orbit J-state dependences for the σ curves of individual electronic states are discernible, indicating that spin-orbit interactions are weak with little effect on chemical reactivity of the titled reaction. For the three product channels identified, the triplet σ(a3FJ) values are overwhelmingly higher than the quintet σ(a5DJ) and σ(a5FJ) values, showing that the reaction is governed by a "weak quintet-triplet spin crossing" mechanism, favoring the conservation of total electron spins. The σ curves for exothermic product channels are found to exhibit a rapid decreasing profile as Ecm is increased, an observation consistent with the prediction of the charge-dipole and induced-dipole orbiting model. This experiment shows that the V+ + H2O reaction can be controlled effectively to produce predominantly the VO+ + H2 channel via the V+(a3FJ) + H2O reaction at low Ecm's (≤0.1 eV) and that the ion-molecule reaction dynamics can be altered readily by selecting the electronic state of V+ cation. On the basis of the measured Ecm thresholds for the σ(a5DJ, a5FJ, and a3FJ: VH+) and σ(a5DJ, a5FJ, and a3FJ: VOH+) curves, we have deduced upper bound values of 2.6 ± 0.2 and 4.3 ± 0.3 eV for the 0 K bond dissociation energies, D0(V+-H) and D0(V+-OH), respectively. After correcting for the kinetic energy distribution resulting from the Doppler broadening effect of the H2O molecule, we obtain D0(V+-H) = 2.2 ± 0.2 eV and D0(V+-OH) = 4.0 ± 0.3 eV, which are in agreement with D0 determinations obtained by σ curve simulations.

Near-Infrared Responsive Doxorubicin Loaded Hollow Mesoporous Prussian Blue Nanoparticles Combined with Dissolvable Hyaluronic Acid Microneedle System for Human Oral Squamous Cell Carcinoma Therapy.

Oral squamous cell carcinoma (OSCC) is one of the most common cancers in developing countries particularly in those aged over 50. Traditional treatment is with surgery, radiotherapy, chemotherapy, or a combination of these which often results in considerable discomfort to the patient. Here we describe a potential alternative which employs a near-infrared (NIR) responsive dissolvable microneedle system (HMPBs&DOX@HA MNs) made of hyaluronic acid (HA) with hollow mesoporous Prussian blue nanoparticles (HMPBs) loaded with doxorubicin (DOX). HMPBs&DOX@HA MNs can easily penetrate the skin, and shows the ability to heat and maintain the internal temperature of tumor tissue at more than 60 C under the irradiation of an NIR laser. Besides, the DOX release behavior can also be regulated by the NIR laser. HMPBs&DOX@HA MNs reveals not only strong cell inhibition in vitro, but also prominent antitumor efficacy in vivo with all tumor-bearing mice cured in just one treatment and with no recurrence. This innovative transdermal drug delivery system minimizes the side effects while eliminating tumors. It has great potential to be an effective clinical treatment of OSCC.

Cavity piezo-mechanics for superconducting-nanophotonic quantum interface.

Hybrid quantum systems are essential for the realization of distributed quantum networks. In particular, piezo-mechanics operating at typical superconducting qubit frequencies features low thermal excitations, and offers an appealing platform to bridge superconducting quantum processors and optical telecommunication channels. However, integrating superconducting and optomechanical elements at cryogenic temperatures with sufficiently strong interactions remains a tremendous challenge. Here, we report an integrated superconducting cavity piezo-optomechanical platform where 10 GHz phonons are resonantly coupled with photons in a superconducting cavity and a nanophotonic cavity at the same time. Taking advantage of the large piezo-mechanical cooperativity (Cem ~7) and the enhanced optomechanical coupling boosted by a pulsed optical pump, we demonstrate coherent interactions at cryogenic temperatures via the observation of efficient microwave-optical photon conversion. This hybrid interface makes a substantial step towards quantum communication at large scale, as well as novel explorations in microwave-optical photon entanglement and quantum sensing mediated by gigahertz phonons.

Radiative Cooling of a Superconducting Resonator.

Cooling microwave resonators to near the quantum ground state, crucial for their operation in the quantum regime, is typically achieved by direct device refrigeration to a few tens of millikelvin. However, in quantum experiments that require high operation power such as microwave-to-optics quantum transduction, it is desirable to operate at higher temperatures with non-negligible environmental thermal excitations, where larger cooling power is available. In this Letter, we present a radiative cooling protocol to prepare a superconducting microwave mode near its quantum ground state in spite of warm environment temperatures for the resonator. In this proof-of-concept experiment, the mode occupancy of a 10 GHz superconducting resonator thermally anchored at 1.02 K is reduced to 0.44±0.05 from 1.56 by radiatively coupling to a 70 mK cold load. This radiative cooling scheme allows high-operation-power microwave experiments to work in the quantum regime, and opens possibilities for routing microwave quantum states to elevated temperatures.

Soliton microcomb generation at 2 µm in z-cut lithium niobate microring resonators.

Chip-based soliton frequency combs have been demonstrated on various material platforms, offering broadband, mutually coherent, and equally spaced frequency lines desired for many applications. Lithium niobate (LN), possessing both second- and third-order optical nonlinearities, as well as integrability on insulating substrates, has emerged as a novel source for microcomb generation and controlling. Here we demonstrate mode-locked soliton microcombs generated around 2 µm in a high-Q z-cut LN microring resonator. The intracavity photorefractive effect is found to be still dominant over the thermal effect in the 2 µm region, which facilitates direct accessing soliton states in the red-detuned regime, as reported in the telecom band. We also find that intracavity stimulated Raman scattering is greatly suppressed when moving the pump wavelength from the telecom band to 2 µm, thus alleviating Raman-Kerr comb competition. This Letter expands mode-locked LN microcombs to 2 µm, and could enable a variety of potential applications based on LN nanophotonic platform.

Chemical Activation of a Deuterium Molecule by Collision with a Quantum Electronic State-Selected Vanadium Cation.

By combining a newly developed spin-orbit electronic state-selected ion source for vanadium cations (V+) with a double quadrupole-double octopole mass spectrometer, we have investigated in detail the chemical reactivity or integral cross sections (σ's) for the reactions of V+[a5DJ (J = 0, 1), a5FJ (J = 1, 2), and a3FJ (J = 2, 3)] ion with a deuterium molecule (D2). The vanadium deuteride ion (VD+) is identified to be the only product ion formed in the center-of-mass collision energies of Ecm = 0.1-10.0 V. No J dependence for the σ's is discernible for individual electronic states, indicating that the spin-orbit coupling is weak and has little effect on the chemical reactivity of the titled reaction. The maximum σ value for the V+(a3FJ) state [σ(a3FJ)] is about 7 and 70 times larger than those for σ(a5DJ) and σ(a5FJ), respectively, showing that the triplet V+(a3FJ) state is dominantly more reactive than the quintet states. Although the V+(a5FJ) state is 0.3 eV higher than the V+(a5DJ) ground state, the chemical reactivity of the V+(a5FJ) state is significantly lower than that of the V+(a5DJ) state, clearly indicating that the differences in chemical activity observed are due to quantum electronic states rather than energy effects. The Ecm thresholds determined for σ(a5DJ), σ(a5FJ), and σ(a3FJ) are consistent with the respective energetics for the formation of VD+ from the V+(a5DJ, a5FJ, and a3FJ) + D2 reactions. The analysis of Ecm threshold measurements yields a bond energy of D0(V+-D) = 2.5 ± 0.2 eV, suggesting that the previously reported values are too low by up to 0.4 eV. The large differences for σ(a5DJ, a5FJ, and a3FJ) observed here indicate that the activation of D2 by a V+ ion can be efficiently controlled by selecting the V+ electronic state as well as the Ecm. The quantum state-selected σ values presented here can also serve as experimental benchmarks for first-principles theoretical reaction dynamics calculations.

Homogeneous ice nucleation rates and crystallization kinetics in transiently-heated, supercooled water films from 188 K to 230 K.

The crystallization kinetics of transiently heated, nanoscale water films were investigated for 188 K < Tpulse < 230 K, where Tpulse is the maximum temperature obtained during a heat pulse. The water films, which had thicknesses ranging from approximately 15-30 nm, were adsorbed on a Pt(111) single crystal and heated with ∼10 ns laser pulses, which produced heating and cooling rates of ∼109-1010 K/s in the adsorbed water films. Because the ice growth rates have been measured independently, the ice nucleation rates could be determined by modeling the observed crystallization kinetics. The experiments show that the nucleation rate goes through a maximum at T = 216 K ± 4 K, and the rate at the maximum is 1029±1 m-3 s-1. The maximum nucleation rate reported here for flat, thin water films is consistent with recent measurements of the nucleation rate in nanometer-sized water drops at comparable temperatures. However, the nucleation rate drops rapidly at lower temperatures, which is different from the nearly temperature-independent rates observed for the nanometer-sized drops. At T ∼ 189 K, the nucleation rate for the current experiments is a factor of ∼104-5 smaller than the rate at the maximum. The nucleation rate also decreases for Tpulse > 220 K, but the transiently heated water films are not very sensitive to the smaller nucleation rates at higher temperatures. The crystallization kinetics are consistent with a "classical" nucleation and growth mechanism indicating that there is an energetic barrier for deeply supercooled water to convert to ice.