Malignancy diagnosis of liver lesion in contrast enhanced ultrasound using an end-to-end method based on deep learning.

BACKGROUND: Contrast-enhanced ultrasound (CEUS) is considered as an efficient tool for focal liver lesion characterization, given it allows real-time scanning and provides dynamic tissue perfusion information. An accurate diagnosis of liver lesions with CEUS requires a precise interpretation of CEUS images. However,it is a highly experience dependent task which requires amount of training and practice. To help improve the constrains, this study aims to develop an end-to-end method based on deep learning to make malignancy diagnosis of liver lesions using CEUS. METHODS: A total of 420 focal liver lesions with 136 benign cases and 284 malignant cases were included. A deep learning model based on a two-dimensional convolution neural network, a long short-term memory (LSTM), and a linear classifier (with sigmoid) was developed to analyze the CEUS loops from different contrast imaging phases. For comparison, a 3D-CNN based method and a machine-learning (ML)-based time-intensity curve (TIC) method were also implemented for performance evaluation. RESULTS: Results of the 4-fold validation demonstrate that the mean AUC is 0.91, 0.88, and 0.78 for the proposed method, the 3D-CNN based method, and the ML-based TIC method, respectively. CONCLUSIONS: The proposed CNN-LSTM method is promising in making malignancy diagnosis of liver lesions in CEUS without any additional manual features selection.

Intrinsic brain activity is increasingly complex and develops asymmetrically during childhood and early adolescence.

A large body of evidence suggests that brain signal complexity (BSC) may be an important indicator of healthy brain functioning or alternately, a harbinger of disease and dysfunction. However, despite recent progress our current understanding of how BSC emerges and evolves in large-scale networks, and the factors that shape these dynamics, remains limited. Here, we utilized resting-state functional near-infrared spectroscopy (rs-fNIRS) to capture and characterize the nature and time course of BSC dynamics within large-scale functional networks in 107 healthy participants ranging from 6-13 years of age. Age-dependent increases in spontaneous BSC were observed predominantly in higher-order association areas including the default mode (DMN) and attentional (ATN) networks. Our results also revealed asymmetrical developmental patterns in BSC that were specific to the dorsal and ventral ATN networks, with the former showing a left-lateralized and the latter demonstrating a right-lateralized increase in BSC. These age-dependent laterality shifts appeared to be more pronounced in females compared to males. Lastly, using a machine-learning model, we showed that BSC is a reliable predictor of chronological age. Higher-order association networks such as the DMN and dorsal ATN demonstrated the most robust prognostic power for predicting ages of previously unseen individuals. Taken together, our findings offer new insights into the spatiotemporal patterns of BSC dynamics in large-scale intrinsic networks that evolve over the course of childhood and adolescence, suggesting that a network-based measure of BSC represents a promising approach for tracking normative brain development and may potentially aid in the early detection of atypical developmental trajectories.

Self-focusing effect analysis of a perfect optical vortex beam in atmospheric turbulence.

The correlation function and the detection probability of orbital angular momentum (OAM) of a perfect optical vortex beam (POVB) were obtained under atmospheric turbulence conditions and then used to estimate the POVB propagation model through atmospheric turbulence. The POVB propagation in a turbulence-free channel can be divided into anti-diffraction and self-focusing stages. The beam profile size can be well preserved in the anti-diffraction stage as the transmission distance increases. After shrinking and focusing the POVB in the self-focusing region, the beam profile size expands in the self-focusing stage. The influence of topological charge on the beam intensity and profile size differs depending on the propagation stage. The POVB degenerates into a Bessel-Gaussian beam (BGB)-like when the ratio of the ring radius to the Gaussian beam waist approaches 1. The unique self-focusing effect of the POVB enables higher received probability compared to the BGB when propagating over long distances in atmospheric turbulence. However, the property of the POVB that its initial beam profile size is not affected by topological charge does not contribute to the POVB achieving a higher received probability than the BGB in short-range transmission application scenarios. The BGB anti-diffraction is stronger than that of the POVB, assuming a similar initial beam profile size at short-range transmission.

Nonlinear topological laser on the non-Hermitian Haldane model with higher-order corner states.

The non-Hermitian skin effect (NHSE) on the non-Hermitian Haldane model with gain and loss on the honeycomb lattice with the outline of a triangle is discussed. The NHSE only occurs on the edge of the lattice, transforming the edge modes into the higher-order corner modes. The NHSE can also occur on a lattice with only loss, which can be treated as a lattice with gain and loss as well as a global loss added to it. When the saturated gain is added to the three corner sites of the dissipative lattice, a single-mode laser system is obtained. When any one site is stimulated initially, the system will reach a saturated state depending on the distribution of the corner modes, and the stable laser light is emitted by sites at the corners.

Topological laser with higher-order corner states in the 2-dimensional Su-Schrieffer-Heeger model.

A nonlinear non-Hermitian topological laser system based on the higher-order corner states of the 2-dimensional (2D) Su-Schrieffer-Heeger (SSH) model is investigated. The topological property of this nonlinear non-Hermitian system described by the quench dynamics is in accordance with that of a normal 2D SSH model. In the topological phase, all sites belonging to the topological corner states begin to emit stable laser light when a pulse is given to any one site of the lattice, while no laser light is emitted when the lattice is in the trivial phase. Furthermore, the next-nearest-neighbor (NNN) couplings are introduced into the strong-coupling unit cells of the 2D SSH model, which open a band gap in the continuous band structure. In the topological phase, similar to the case of 2D SSH model without NNN couplings, the corner sites can emit stable laser light due to the robustness of the higher-order corner states when the NNN couplings are regarded as the perturbation. However, amplitude of the stimulated site does not decay to zero in the trivial phase, because the existence of the NNN couplings in the strong-coupling unit cells make the lattice like one in the tetramer limit, and a weaker laser light is emitted by each corner.

Passive white light cavities with metal coatings.

White light cavities with broadband resonance are usually filled with negative dispersion medium, which inevitably leads to gain. In this article, pure passive white light cavities are designed, in which negative dispersion medium is no longer necessary. Theoretically, if the reflection phase of the cavity wall can exhibit a negative dispersion slope, then it can also satisfy white light cavities conditions without medium. In practice, the negative dispersion property of the cavity wall can be realized by two metal coatings with different reflection coefficients. Therefore, our white light cavities are composite cavities, in which the main cavity provides resonance while the auxiliary cavity forms the cavity wall, providing negative dispersion reflection phase. Further, atomic gas can be employed to improve the performance of the white light cavities. Atomic gas exploits effects such as Electromagnetic Induced Transparency (EIT), enabling the white light cavities to be controlled by coherent driving field. With the passive characters, our design can be realized and implemented much more easily.

Influence of a topological artificial atom chain on the transmission properties of a cavity.

We explore the influence of the artificial atomic chain on the input-output relation of the cavity. Specifically, we extend the atom chain to the one-dimensional Su-Schrieffer-Heeger (SSH) chain to check the role of atomic topological non-trivial edge state on the transmission characteristics of the cavity. The superconducting circuits can realize the artificial atomic chain. Our results show that the atom chain is not equivalent to atom gas, and the transmission properties of the cavity containing the atom chain are entirely different from that of the cavity containing atom gas. When the atom chain is arranged in the form of topological non-trivial SSH model, the atom chain can be equivalent to the three-level atom, in which the edge state contributes to the second level and is resonant with the cavity, while the high-energy bulk state contributes to form the third level and is greatly detuned with the cavity. Therefore, the transmission spectrum shows no more than three peaks. This allows us to infer the topological phase of the atomic chain and the coupling strength between the atom and the cavity only from the profile of the transmission spectrum. Our work is helping to understand the role of topology in quantum optics.

PRMT5 Prevents Dilated Cardiomyopathy via Suppression of Protein O-GlcNAcylation.

[Figure: see text].

Penicopeptide A (PPA) from the deep-sea-derived fungus promotes osteoblast-mediated bone formation and alleviates ovariectomy-induced bone loss by activating the AKT/GSK-3ß/ß-catenin signaling pathway.

The potential of marine natural products as effective drugs for osteoporosis treatment is an understudied area. In this study, we investigated the ability of lead compounds from deep-sea-derived Penicillium solitum MCCC 3A00215 to promote bone formation in vitro and in vivo. We found that penicopeptide A (PPA) promoted osteoblast mineralization among bone marrow mesenchymal stem cells (BMSCs) in a concentration-dependent manner, and thus, we selected this natural peptide for further testing. Our further experiments showed that PPA significantly promoted the osteogenic differentiation of BMSCs while inhibiting their adipogenic differentiation and not affecting their chondrogenic differentiation. Mechanistic studies showed that PPA binds directly to the AKT and GSK-3ß and activates phosphorylation of AKT and GSK-3ß, resulting in the accumulation of ß-catenin. We also evaluated the therapeutic potential of PPA in a female mouse model of ovariectomy-induced systemic bone loss. In this model, PPA treatment prevented decreases in bone volume and trabecular thickness. In conclusion, our in vitro and in vivo results demonstrated that PPA could promote osteoblast-related bone formation via the AKT, GSK-3ß, and ß-catenin signaling pathways, indicating the clinical potential of PPA as a candidate compound for osteoporosis prevention.

Improved detectivity and response speed of MoS2 phototransistors based on the negative-capacitance effect and defect engineering.

Due to the unique crystal structure, outstanding optoelectronic properties and a tunable band gap from 1.2-1.8 eV, two-dimensional molybdenum disulfide (MoS2) has attracted extensive attention as a promising candidate for future photodetectors. In this work, a negative-capacitance (NC) MoS2 phototransistor is fabricated by using H f 0.5 Z r 0.5 O 2 (HZO) as ferroelectric layer and Al2O3 as matching layer, and a low subthreshold swing (SS) of 39 mV/dec and an ultrahigh detectivity of 3.736×1014 cmHz1/2W-1 are achieved at room temperature due to the NC effect of the ferroelectric HZO. Moreover, after sulfur (S) treatment on MoS2, the transistor obtained a lower SS of 33 mV/dec, a detectivity of 1.329×1014 cmHz1/2W-1 and specially a faster response time of 3-4 ms at room temperature, attributed to the modulation of photogating effect induced by S-vacancy passivation in MoS2 by the S treatment. Therefore, the combination of the defect engineering on MoS2 and the NC effect from ferroelectric thin film could provide an effective solution for high-sensitivity phototransistors based on two-dimensional materials in the future.

Improvement of nonreciprocal unconventional photon blockade by two asymmetrical arranged atoms embedded in a cavity.

We improve the nonreciprocal unconventional photon blockade (UCPB) in an asymmetrical single-mode cavity with two asymmetrical arranged two-level atoms (TLAs) where cavity and atom spatial symmetry breakings are involved in. In order to get direction-dependent UCPB in asymmetrical system, we deduce two restrictions of frequency and intensity through the steady solution of the cavity QED system analytically. The former restriction is exactly the same as that of a single-atom case, and the latter restriction combined with both spatial asymmetries. Controllable UCPB in this model shows an improving nonreciprocal UCPB with wider operating regime which is promoted by two asymmetrical arranged atoms. The most innovation of this work is that the contributions of two spatial symmetry breakings are figured out clearly and they play different roles in nonreciprocal UCPB. The cavity spatial symmetry breaking and weak nonlinearity are essential to quantum nonreciprocity, while the atoms spatial symmetry is not and it only can promote such nonreciprocal UCPB. Our findings show a prospective access to manipulate quantum nonreciprocity by a couple of atoms.

Chiral interaction of an atom in a sandwiched waveguide.

The chiral interaction between light and matter is mainly caused by the spin-momentum locking and makes the chiral quantum optics enter a vigorous development stage. Here, we explore the condition of the perfect chiral interaction between an atom possessing circular dipole and the surface plasmon polariton (SPP) mode. The realization of the perfect chiral interaction must satisfy the following two conditions at the same time. First, the SPP mode should possess the transverse circular polarization; and second, the atom decays mainly into the SPP mode, while the decay through other channel can be ignored. In this paper, we adopt a simple but effective structure to satisfy both of requirements, which is the sandwiched waveguide made of metal. We found that the transverse circular polarization of SPP mode might be achieved within the structure possessing multiple interfaces instead of the interface separating two semi-infinite materials. In our model, the decay rate into SPP mode overwhelms that through traveling wave, which provides higher quantum efficiency. What's more, we found that only the symmetric TM-polarized SPP mode might get the transverse circular polarization. For the sandwiched structure containing metal, the existence of two SPP modes weakens the overall chiral interaction. However, the structure containing left-handed materials (LHMs), which can only support one symmetric TM-polarized SPP mode, can get the nearly perfect chiral interaction. We measure the chiral interaction through the decay rate, radiation field distribution and the unidirectional rate through the energy flux. Our work provides a reference for exploring the perfect chiral interaction in more complex structures and has potential and wide applicability to other optical processes.

Interaction of two quantum dots mediated by edge modes of coupled-cavity arrays.

Topological photonics is a hot topic in recent years. We combine it with the quantum optics and explore the dynamics of two quantum dots (QDs) separated by the finite coupled-cavity arrays (CCAs). The finite CCAs possessing the alternating hopping strengths will lead to the existence of the topological protected edge modes, also called zero energy modes, when the boundaries leave the weak hopping at two ends. Due to the two edge modes, i.e., symmetric and antisymmetric, with nearly degenerate frequencies, the dynamics of two QDs coupled to the cavities at both ends exhibit complicated behaviors. When the CCAs are composed of a large number of cavities, there are two kinds of phenomena: if the coupling between QDs and cavity is weak, two edge modes will cancel each other out and isolate two QDs deeply; if the coupling between QDs and cavities is large compared with hopping strength, the edge mode disappears and two QDs can be connected through extend modes. Importantly, when the CCAs are formed by a small number of cavities, energy can be transferred to each other between two QDs through the edge modes. Such energy transfer is topologically protected, and the period is long and easily controlled. We also investigate the effects of topologically protected quantum entangled states on such system and find that the quantum entanglement can be well kept or generated for appropriate choices of system parameters and initial states. The investigations enrich the manifestation of topological physics and are helpful to apply the topological protection to quantum computation and quantum communication.

Improved subthreshold swing of MoS2 negative-capacitance transistor by fluorine-plasma treatment on ferroelectric Hf0.5Zr0.5O2 gate dielectric.

In this work, the ferroelectricity of hafnium zirconium oxide (Hf0.5Zr0.5O2, HZO) is enhanced by fluorine (F)-plasma treatment, which is used to fabricate MoS2 negative-capacitance field-effect transistor. Measurements show that the subthreshold swing of the transistor is significantly reduced to 17.8 mV dec-1 over almost four orders of output current, as compared to its counterpart without the F-plasma treatment (37.4 mV dec-1). The involved mechanism is that during the F-plasma treatment, F atoms can be incorporated into the HZO bulk to passive its oxygen vacancies and interface traps, thus forming robust Zr-F and Hf-F bonds. Therefore, the F-plasma-treated HZO film exhibits much less oxygen vacancies than the untreated HZO film, which is beneficial to enhancing the amplification effect on the surface potential of the MoS2 channel during the NC operation.

Impacts of HfZrO thickness and anneal temperature on performance of MoS2negative-capacitance field-effect transistors.

The MoS2negative-capacitance field-effect transistor (NCFET) with the ultra-thin (3 nm) HfZrO (HZO) as NC layer and 2 nm Al2O3as dielectric layer is successfully fabricated by optimizing the annealing temperature and the HZO thickness. Excellent subthreshold swing (SS = 33.1 mV dec-1) is achieved, with an on/off current ratio of 1.16 × 107. The relevant negative-drain-induced barrier lowing effect and the negative differential resistance effect are observed in the MoS2NCFET. Such low SS implies that only a small gate-voltage increment can transfer the transistor from off state to on state, i.e. an excellent switching and low power-consumption characteristics. The involved mechanisms lie in a suitable anneal temperature for ferroelectric phase transition and a reasonably ultra-thin HZO thickness for the optimum capacitance matching.

MoS2transistors gated by ferroelectric HfZrO2with MoS2/mica heterojunction interface.

Two-dimensional (2D) molybdenum disulfide (MoS2) field-effect transistor (FET) gated by negative capacitance (NC) is a promising architecture to overcome the thermionic limit and thus reduce device consumption. Here, top-gated MoS2NCFETs have been prepared by transferring a mica flake on MoS2channel to form a van der Waals heterojunction interface, together with a ferroelectric HfZrO2(HZO) deposited on mica. Stable NC effects are demonstrated for MoS2NCFETs. The MoS2NCFETs integrated with mica/HZO gate stack provide competitive electrical characteristics when they are applied with a gate voltage sweep-width in the range of 1-3 V and a sweep-rate from 0.01 to 0.2 V s-1, including steep-slope of sub 60 mV dec-1in four orders of magnitude of drain current, on/off current ratio over 106, and small hysteresis-width less than 50 mV. Outstanding performance should be ascribed to damage-free properties of mica/MoS2van der Waals interface and capacitance matching between the HZO ferroelectric and mica dielectric. The results confirm the promising nature of mica/HZO gate stack and potential applications for future electronics.

All-optical negative differential transporter of Bose-Einstein condensates in cavity.

We present a new and interesting physical phenomenon of optical negative differential transmission (ONDT, whose output intensity decreases with the increasing of input field intensity for an arbitrary optical system) in present BEC-cavity coupling system which pumped by a strong light and probed by a weak light. Theoretical results show that the transmission of the probe can be suppressed or promoted greatly by the pump due to optical nonlinearity and the Stokes/anti-Stokes scattering. To our most interest, two kinds of ONDT respectively induced by the nonlinear incoherent light-controlling and the nonlinear coherent interference have been uncovered, which have promising prospect in producing hyper-stable light source since it provides an unusual negative feedback.

Long-term stability of multilayer MoS2 transistors with mica gate dielectric.

To avoid surface damage of a MoS2 channel, a mica flake with high permittivity and atomically flat surface was dry transferred onto a multilayer MoS2 flake to prepare top-gated transistors. For the first time, the interface properties of mica/MoS2 and the long-term stability of devices were investigated when the transistors were exposed to ambient air. Results show that the electrical performance of the transistors is degraded significantly when the devices are exposed to ambient moisture for a long time, due to the strong hydrophilism of mica. The transfer curves of the transistors cannot be recovered to their initial states even after annealing. The adsorbed moisture can become trapped at the interface between the MoS2 channel and mica dielectric or on the MoS2 surface, resulting in enhanced carrier scattering and degraded device performance. However, the top-gated MoS2 transistor with Al2O3 encapsulation exhibits enhanced stability even after annealing or exposure to atmosphere for 200 days. The excellent stability should be attributed to the effective insulation of moisture from the ambient air by Al2O3 encapsulation. Therefore, a dense and hydrophobic encapsulation layer is indispensable for stable and high-performance top-gated MoS2 transistors with mica gate dielectric.

Optimizing Al-doped ZrO2 as the gate dielectric for MoS2 field-effect transistors.

In this work, we investigate the effects on the electrical properties of few-layered MoS2 field-effect transistors (FETs) following Al incorporation into ZrO2 as the gate dielectrics of the devices. A large improvement in device performance is achieved with the Al-doped ZrO2 gate dielectric when Zr:Al = 1:1. The relevant MoS2 transistor exhibits the best electrical characteristics: high carrier mobility of 40.6 cm2 V-1 s-1 (41% higher than that of the control sample, and an intrinsic mobility of 68.0 cm2 V-1 s-1), a small subthreshold swing of 143 mV dec-1, high on/off current ratio of 6 × 106 and small threshold voltage of 0.71 V. These are attributed to the facts that (i) Al incorporation into ZrO2 can decrease its oxygen vacancies; densify the dielectric film; and smooth the gate dielectric surface, thus reducing the traps at/near the Zr0.5Al0.5O y /MoS2 interface and the gate leakage current; (ii) adjusting the dielectric constant of the gate dielectric to an appropriate value, which achieves a reasonable trade-off between the gate screening effect on the Coulomb-impurity scattering and the surface optical phonon scattering. These results demonstrate that optimized Zr0.5Al0.5Oy is a potential gate dielectric material for MoS2 FET applications.

Enhancement of long-distance Casimir-Polder interaction between an excited atom and a cavity made of metamaterials.

Within the framework of macroscopic quantum electrodynamics, we investigate both the radiation force and the potential of Casimir-Polder type acting on an excited cold two-level atom in a cavity made of left-handed materials and topological insulators. As the time-reversal symmetry is broken on the surface of the topological insulators, the spontaneous emission of the atom placed near the focus point(s) exhibits anisotropic properties. While the potential wells are normally shallow for topological trivial dielectric, they may be amplified in the presence of topological magnetoelectric effect. We find that when there exists only one focus point in the cavity, it is possible to boost the forces or the potential wells by up to one order of magnitude. Meanwhile, the lifetime of the atom could be prolonged owing to the focus effect of the left-handed materials, where the emitted photons can trace back to the atom and reabsorbed by itself. Our results indicate the possibility in forming long-lived potential wells, which may have potential applications in trapping and guiding cold atoms far away from the surface.