Achieving human-like dexterous robotic manipulation remains a central goal and a pivotal challenge in robotics. The development of Artificial Intelligence (AI) has allowed rapid progress in robotic manipulation. This survey summarizes the evolution of robotic manipulation from mechanical programming to embodied intelligence, alongside the transition from simple grippers to multi-fingered dexterous hands, outlining key characteristics and main challenges. Focusing on the current stage of embodied dexterous manipulation, we highlight recent advances in two critical areas: dexterous manipulation data collection (via simulation, human demonstrations, and teleoperation) and skill-learning frameworks (imitation and reinforcement learning). Then, based on the overview of the existing data collection paradigm and learning framework, three key challenges restricting the development of dexterous robotic manipulation are summarized and discussed.

Surgical robots capable of autonomously performing various tasks could enhance efficiency and augment human productivity in addressing clinical needs. Although current solutions have automated specific actions within defined contexts, they are challenging to generalize across diverse environments in general surgery. Embodied intelligence enables general-purpose robot learning with applications for daily tasks, yet its application in the medical domain remains limited. We introduced an open-source surgical embodied intelligence simulator for an interactive environment to develop reinforcement learning methods for minimally invasive surgical robots. Using such embodied artificial intelligence, this study further addresses surgical task automation, enabling zero-shot transfer of simulation-trained policies to real-world scenarios. The proposed method encompasses visual parsing, a perceptual regressor, policy learning, and a visual servoing controller, forming a paradigm that combines the advantages of data-driven policy and classic controller. The visual parsing uses stereo depth estimation and image segmentation with a visual foundation model to handle complex scenes. Experiments demonstrated autonomy in seven game-based skill training tasks on the da Vinci Research Kit, with a proof-of-concept study on haptic-assisted skill training as a practical application. Moreover, we conducted automation of five surgical assistive tasks with the Sentire surgical system on ex vivo animal tissues with various scenes, object sizes, instrument types, and illuminations. The learned policies were also validated in a live-animal trial for three tasks in dynamic in vivo surgical environments. We hope this open-source infrastructure, coupled with a general-purpose learning paradigm, will inspire and facilitate future research on embodied intelligence toward autonomous surgical robots.

Recent success in generative AI has demonstrated great potential in various medical scenarios. However, how to generate realistic and high-fidelity gastrointestinal laparoscopy videos still lacks exploration. A recent work, Endora, proposes a basic generation model for a gastrointestinal laparoscopy scenario, producing low-resolution laparoscopy videos, which can not meet the real needs in robotic surgery. Regarding this issue, we propose an innovative two-stage video generation architecture HiEndo for generating high-resolution gastrointestinal laparoscopy videos with high fidelity. In the first stage, we build a diffusion transformer for generating a low-resolution laparoscopy video upon the basic capability of Endora as an initial start. In the second stage, we further design a super resolution module to improve the resolution of initial video and refine the fine-grained details. With these two stages, we could obtain high-resolution realistic laparoscopy videos with high fidelity, which can meet the real-world clinical usage. We also collect a large-scale gastrointestinal laparoscopy video dataset with 61,270 video clips for training and validation of our proposed method. Extensive experimental results have demonstrate the effectiveness of our proposed framework. For example, our model achieves 15.1% Fréchet Video Distance and 3.7% F1 score improvements compared with the previous state-of-the-art method.

Recent LHAASO observations hint at potential spectral hardening around 20 TeV in M87’s very high energy emission, suggesting a possible new radiation component. In this work, we construct averaged multiwavelength spectral energy distributions by combining data from Chandra and Swift-UVOT/XRT covering the same period as the LHAASO detection to investigate the origin of this feature. We test several radiation mechanisms, including the pp interaction, proton synchrotron emission, photomeson process, and two-zone leptonic model. We find that only the pion decay gamma rays in pp interactions can interpret this feature in the framework of the one-zone model. With analytical analysis, we prove that proton synchrotron emission cannot generate a hard spectrum above 0.17 TeV. The photomeson model requires an emission zone compressed near the Schwarzschild radius of the central supermassive black hole, incompatible with broadband optical-GeV spectral constraints. In addition, the two-zone leptonic model also emerges as a viable alternative.

Blazars are often observed to flare across multiple wavelengths. Orphan flares from blazars have only been detected a few times, providing an opportunity to understand the structure of the jet in the accreting system. We report a remarkable orphan X-ray flare from a blazar candidate EP240709a, detected by the Einstein Probe (EP) in July 2024. The multiband spectral properties and variability support EP240709a as a high-energy peaked BL Lacertae-type object. The flux in 0.5–10 keV increased by at least 28 times to the value of low state in 2020, with no significant flaring detected in other bands during the same period. EP240709a exhibits the harder-when-brighter tendency in the X-ray band during the orphan flare, while its infrared-optical spectra are featureless. We employ one-zone and two-zone leptonic synchrotron self-Compton models to perform the spectral energy distribution fitting. Detecting this rare orphan flare shows the potential of EP in discovering peculiar activities from AGN in high-cadence X-ray sky surveys.

Due to its proximity, Markarian 421 is one of the most extensively studied jetted active galactic nuclei. Its spectral energy distribution and light curve are widely studied, serving as primary means for understanding jet radiation mechanisms. Numerous intriguing observational results have been discovered, some of which, such as the hard X-ray excess, and the associated variability between X-ray and very-high-energy (VHE) emissions, challenge the commonly adopted one-zone leptonic model. In this work, by establishing a time-dependent leptohadronic model, we explore whether the hard X-ray excess and the associated variability between X-ray and VHE emissions could be interpreted by emission from hadronic interactions. Our modeling finds that for the hard X-ray excess found in 2013, both of the secondary emissions from photohadronic and hadronuclear interactions could be a possible explanation for the hard X-ray excess without introducing a super-Eddington jet power. The emission from the photohadronic interactions contributes only to the hard X-ray band, while the hadronuclear interactions also predict VHE emissions associated with the hard X-rays. While for the hard X-ray excess found in 2016, only the secondary emissions from photohadronic interactions provide an interpretation at the cost of introducing a super-Eddington jet power. For the associated variability between X-ray and VHE emissions in 2017, we find that hadronic interactions fail to provide a possible interpretation.

The discovery that blazars dominate the extra-galactic gamma -ray sky is a triumph in the Fermi era. However, the exact location of gamma -ray emission region still remains in debate. Low-synchrotron-peaked blazars (LSPs) are estimated to produce high-energy radiation through the external Compton process, thus their emission regions are closely related to the external photon fields. We employed the seed factor approach proposed by Georganopoulos et al. It directly matches the observed seed factor of each LSP with the characteristic seed factors of external photon fields to locate the gamma -ray emission region. A sample of 1 138 LSPs with peak frequencies and peak luminosities was adopted to plot a histogram distribution of observed seed factors. We also collected some spectral energy distributions (SEDs) of historical flare states to investigate the variation of gamma -ray emission region. Those SEDs were fitted by both quadratic and cubic functions using the Markov-chain Monte Carlo method. Furthermore, we derived some physical parameters of blazars and compared them with the constraint of internal gamma gamma -absorption. We find that dusty torus dominates the soft photon fields of LSPs and most gamma -ray emission regions of LSPs are located at 1-10 pc. The soft photon fields could also transition from dusty torus to broad line region and cosmic microwave background in different flare states. Our results suggest that the cubic function is better than the quadratic function to fit the SEDs.

The ability to recover tissue deformation from surgical video is fundamental for many downstream applications in robotic surgery. Despite noticeable advancements, this task remains under-explored due to the complex dynamics of soft tissues manipulated by surgical instruments. Achieving dense and accurate tissue tracking is further complicated by ambiguous pixel correspondence in regions with homogeneous texture. In this paper, we introduce a novel self-supervised framework to recover tissue deformations from stereo surgical videos. Our approach integrates semantics, cross-frame motion flow, and long-range temporal dependencies to accurately represent tissue dynamics for deformation recovery. Moreover, we incorporate diffeomorphic mapping to regularize the warping field to be physically more realistic. To comprehensively evaluate our method, we collected stereo surgical video clips containing three types of tissue manipulation (i.e., pushing, dissection and retraction) from two surgical procedures (i.e., hemicolectomy and mesorectal excision). Our method demonstrates promising results in capturing tissue 3D deformation, and generalizes well across different actions and procedures. It also outperforms current state-of-the-art approaches based on non-rigid registration and optical flow estimation. To the best of our knowledge, this is the first work on self-supervised learning for dense tissue deformation modeling from stereo surgical videos. The paper's code is available at: https://github.com/ med-air/RecoverTissueDeform.

The origin of diffuse high-energy neutrinos from TeV to PeV energies detected by IceCube Observatory remains a mystery. In our previous work, we have shown that hadronuclear (p-p) interactions in AGN jets could be important and generate detectable very-high-energy emissions. Here, we further explore these interactions in the AGN jets based on their luminosity function. The diffuse neutrino flux and corresponding γ-ray flux have been calculated and compared with observational data. In our modeling, two beaming patterns are considered separately. To make sure that the corresponding γ-ray flux does not overshoot the diffuse γ-ray background, we find that if the neutrino production region in jet is opaque to γ rays, p-p interactions in AGN jets with a small viewing angle (the blazar case) are able to interpret the PeV neutrino background. Similarly, AGN jets with a large viewing angle (the radio galaxy case) may interpret the TeV neutrino background. While, if the neutrino production region is transparent to γ rays, only blazars have the potential to interpret the DNB around PeV band. Some caveats are also discussed.

The origin of diffuse high-energy neutrinos from TeV to PeV energies detected by the IceCube Observatory remains a mystery. In our previous work, we have shown that hadronuclear ( p − p ) interactions in active galactic nuclei (AGNs) jets could be important and generate detectable very-high-energy emissions. Here, we further explore these interactions in the AGN jets based on their luminosity function. The diffuse neutrino flux and corresponding γ -ray flux have been calculated and compared with observational data. In our modeling, two beaming patterns are considered separately. To make sure that the corresponding γ -ray flux does not overshoot the diffuse γ -ray background, we find that if the neutrino production region in a jet is opaque to γ -rays, p − p interactions in AGN jets with a small viewing angle (the blazar case) are able to interpret the PeV neutrino background. Similarly, AGN jets with a large viewing angle (the radio galaxy case) may interpret the TeV neutrino background. While, if the neutrino production region is transparent to γ -rays, only blazars have the potential to interpret the diffuse neutrino background around the PeV band. Some caveats are also discussed.

Recently, the Large High Altitude Air Shower Observatory (LHAASO) collaboration presented the first catalog of γ -ray sources using 508 days of LHAASO data, from 2021 March to 2022 September. This catalog contains four blazars and a possible LINER-type active galactic nucleus (AGN) counterpart. In this work, we establish averaged multiwavelength spectral energy distributions (SEDs) by combining data from the Fermi-Large Area Telescope, Swift, Zwicky Transient Facility, and Wide-field Infrared Survey Explorer (WISE) covering the same period as the LHAASO detection. In general, these five AGNs are found in low states at all wavelengths. To study the multiwavelength properties of these AGNs, several jet emission models, including the one-zone leptonic model, the one-zone leptonic and hadronuclear ( pp ) model, the one-zone proton-synchrotron model, and the spine-layer model, are applied to reproduce their averaged SEDs. We find that the one-zone leptonic model can reproduce most of the SEDs, except for the high-energy tail of the LHAASO spectra of Mrk 421 and Mrk 501. To improve the fitting, emission from pp interactions is favored in the framework of a one-zone model. The spine-layer model, which can be treated as a multizone scenario, can also provide good spectral fits. The influence of different extragalactic background light models on fitting a LHAASO energy spectrum is also discussed.

The blazar TXS 0506+056 has been proposed as a high-energy neutrino emitter. However, it has been shown that the standard one-zone model cannot produce sufficiently high neutrino flux due to constraints from the X-ray data, implying more complex properties of the radiation zones in the blazar than that described by the standard one-zone model. In this work, we investigate multiepoch high-energy muon-neutrino events associated with the blazar TXS 0506+056 that occurred in 2014–2015, 2017–2018, 2021–2022, and 2022–2023, respectively. We applied the so-called “stochastic dissipation model” to account for the neutrino-blazar associations detected in the four epochs simultaneously. This model describes a scenario in which the emission of the blazar arises from the superimposition of two components: a persistent component related to the quasi-stable state of the blazar and a transient component responsible for the sudden enhancement of the blazar’s flux, either in electromagnetic radiation or in neutrino emission. The latter component could form at a random distance along the jet by a strong energy dissipation event. Under such an assumption, the multiepoch broadband spectral energy distribution can be well explained, and the expected number of high-energy neutrino events is statistically realistic. The expected number of neutrino events in half year is around 8.2, 0.07, 0.73, and 0.41, corresponding to the epoch in 2014–2015, 2017–2018, 2021–2022, and 2022–2023, respectively. Hence, our model self-consistently explains the episodic neutrino emission from TXS 0506+056.

ABSTRACT Previous studies on the fitting of spectral energy distributions (SEDs) often apply the external-Compton process to interpret the high-energy peak of low-synchrotron-peaked (LSP) BL Lac objects (LBLs), despite the lack of strong broad emission lines observed for LBLs. In this work, we collect quasi-simultaneous multiwavelength data of 15 LBLs from the Fermi fourth LAT AGN catalogue (4LAC). We propose an analytical method to assess the necessity of external photon fields in the framework of one-zone scenario. Following derived analytical results, we fit the SEDs of these LBLs with the conventional one-zone leptonic model and study their jet physical properties. Our main results can be summarized as follows. (1) We find that most LBLs cannot be fitted by the one-zone synchrotron-self-Compton (SSC) model. This indicates that external photons play a crucial role in the high-energy emission of LBLs, therefore we suggest that LBLs are masquerading BL Lacs. (2) We suggest that the γ-ray emitting regions of LBLs are located outside the broad-line region and within the dusty torus. (3) By extending the analytical method to all types of LSPs in Fermi-4LAC (using historical data), we find that the high-energy peaks of some flat spectrum radio quasars and blazar candidates of unknown types can be attributed to the SSC emission, implying that the importance of external photons could be minor. We suggest that the variability time-scale may help distinguish the origin of the high-energy peak.

ABSTRACT The blazar sequence, including negative correlations between radiative luminosity Lrad and synchrotron peak frequency ν, and between Compton dominance Y and ν, is widely adopted as a phenomenological description of spectral energy distributions (SEDs) of blazars, although its underlying cause is hotly debated. In particular, these correlations turn positive after correcting Doppler boosting effect. In this work, we revisit the phenomenological and intrinsic blazar sequence with three samples, which are historical sample (SEDs are built with historical data), quasi-simultaneous sample (SEDs are built with quasi-simultaneous data) and Doppler factor corrected sample (a sample with available Doppler factors), selected from literature. We find that phenomenological blazar sequence holds in historical sample, but does not exist in quasi-simultaneous sample, and intrinsic correlation between Lrad and ν becomes positive in Doppler factor corrected sample. We also analyse if the blazar sequence still exists in subclasses of blazars, i.e. flat-spectrum radio quasars and BL Lacertae objects, with different values of Y. To interpret these correlations, we apply a simple scaling model, in which physical parameters of the dissipation region are connected to the location of the dissipation region. We find that the model generated results are highly sensitive to the chosen ranges and distributions of physical parameters. Therefore, we suggest that even though the simple scaling model can reproduce the blazar sequence under specific conditions that have been fine-tuned, such results may not have universal applicability. Further consideration of a more realistic emission model is expected.

Background Definitive diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) relies on the examination of brain tissues for the pathological prion protein (PrPSc). Our previous study revealed that PrPSc-seeding activity (PrPSc-SA) is detectable in skin of sCJD patients by an ultrasensitive PrPScseed-amplification assay (PrPSc-SAA) known as real-time quaking-induced conversion (RT-QuIC).Methods 875 skin samples were retrospectively and prospectively collected at autopsy from three body areas of 335 cases with neuropathologically confirmed sCJD and non-sCJD controls. These samples were analyzed for skin PrPSc-SA by RT-QuIC in two independent laboratories. The results were compared with demographic information, clinical manifestations, cerebrospinal fluid (CSF) PrPSc-SA, and other laboratory tests in deceased patients.Findings RT-QuIC assays of the retrospective cohort in the two laboratories gave the same 84.5% sensitivity and 100% specificity. The prospective cohort showed sensitivity of 83.2% and specificity of 97.3%. RT-QuIC of CSF available from 212 cases gave 89.7% sensitivity and 94.4% specificity. The sensitivity of skin RT-QuIC was subtype-dependent, being highest in sCJDVV1-2 subtype, followed by VV2, MV1-2, MV1, MV2, MM1, MM1-2, MM2, and VV1. The skin area next to the ear gave highest sensitivity, followed by lower back and apex of the head. Although no difference in brain PrPSc-SA was detected between the cases with false negative and true positive skin RT-QuIC results, the disease duration was significantly longer with the false negatives [12.0 ± 13.3 (months, SD) vs 6.5 ± 6.4, p < 0.001].Interpretation Our study validates PrPSc-SA as a useful biomarker for the diagnosis of sCJD.Funding: The CJD Foundation, National Institutes of Health (NIH) NS109532, NS096626, NS118760, Alzheimer’s Association, Alzheimer’s Research UK, Michael J. Fox Foundation for Parkinson’s Research, Weston Brain Institute, USDA, the Intramural Research Program of the NIH, CDC, and a gift to NIAID (NIH) from the Smith family in memory of Jeffrey Smith.Declaration of Interest: BC has US Patent 8,216,788 and European Patent EP 2554996 pertaining to RT-QuIC testing. All other authors declare that they have no competing interests. Ethical Approval: This study was approved by the Institutional Review Board (IRB) of University Hospitals Cleveland Medical Center.

The radiation mechanism of Radio-Loud Narrow-Line Seyfert 1 (RL-NLS1) galaxies from X-ray to γ -ray bands remains an open question. While the leptonic model has been employed to explain the spectral energy distribution (SED), the hadronic process may potentially account for the high-energy radiation of some γ -ray-loud Narrow-Line Seyfert 1 (NLS1) galaxies as well. We study one of such RL-NLS1s, PKS 1502+036, comparing the theoretical SEDs predicted by the leptonic model and the lepto-hadronic model to the observed one. For the hadronic processes, we take into account the proton synchrotron radiation and proton–photon interactions (including the Bethe–Heitler process and the photopion process) including the emission of pairs generated in the electromagnetic cascade initiated by these processes. Our results show that the leptonic model can reproduce the SED of this source, in which the X-ray to γ -ray radiation can be interpreted as the inverse Compton scattering. On the other hand, the proton synchrotron radiation can also explain the high-energy component of SED although extreme parameters are needed. We also demonstrate that the p γ interactions as well as the cascade process cannot explain SED. Our results imply that a leptonic origin is favored for the multiwavelength emission of PKS 1502+036.

Recently, the Large High Altitude Air Shower Observatory (LHAASO) collaboration presented the first catalog of $\gamma$-ray sources using 508 days of LHAASO data, from March 2021 to September 2022. This catalog contains four blazars and a possible liner-type AGN counterpart. In this work, we establish averaged multi-wavelength SEDs by combining data from the \textsl{Fermi}-Large Area Telescope, \textsl{Swift}, ZTF, and WISE covering the same period as the LHAASO detection. In general, these five AGNs are found in low states at all wavelengths. To study the multi-wavelength properties of these AGNs, several jet emission models, including the one-zone leptonic model, the one-zone leptonic and hadronuclear ($pp$) model, the one-zone proton-synchrotron model, and the spine-layer model are applied to reproduce their averaged SEDs, respectively. We find that the one-zone leptonic model can reproduce most of the SEDs, except for the high-energy tail of the LHAASO spectra of Mrk 421 and Mrk 501. To improve the fitting, emission from $pp$ interactions is favoured in the framework of a one-zone model. The spine-layer model, which can be treated as a multi-zone scenario, can also provide good spectral fits. The influence of different extragalactic background light models on fitting LHAASO energy spectrum is also discussed.

ABSTRACT In this work, a time-dependent modelling is developed to study the emission properties of blazars in the low state. Motivated by various observations, we speculate and assume that numerous discrete radiation zones throughout the jet of a blazar contribute to the broad-band emission. We model the temporal evolution of the electron spectrum in each emission zone taking into account the injection, cooling, and escape of relativistic electrons. By doing so, we are able to calculate the multiwavelength emission of each radiation zone. The observed emission of a blazar is then the superposition of the emission from all discrete radiation zones. We revisit the multiwavelength spectral energy distributions, light curves, and polarization under the model, and discuss its potential to reproduce the flat radio spectra, the core-shift phenomena, the minute-scale gamma-ray variability, and the large polarization-angle swings, which are difficult to explain under the conventional one-zone models simultaneously.