642 research outputs found
AutoLaparo: A New Dataset of Integrated Multi-tasks for Image-guided Surgical Automation in Laparoscopic Hysterectomy
Computer-assisted minimally invasive surgery has great potential in
benefiting modern operating theatres. The video data streamed from the
endoscope provides rich information to support context-awareness for
next-generation intelligent surgical systems. To achieve accurate perception
and automatic manipulation during the procedure, learning based technique is a
promising way, which enables advanced image analysis and scene understanding in
recent years. However, learning such models highly relies on large-scale,
high-quality, and multi-task labelled data. This is currently a bottleneck for
the topic, as available public dataset is still extremely limited in the field
of CAI. In this paper, we present and release the first integrated dataset
(named AutoLaparo) with multiple image-based perception tasks to facilitate
learning-based automation in hysterectomy surgery. Our AutoLaparo dataset is
developed based on full-length videos of entire hysterectomy procedures.
Specifically, three different yet highly correlated tasks are formulated in the
dataset, including surgical workflow recognition, laparoscope motion
prediction, and instrument and key anatomy segmentation. In addition, we
provide experimental results with state-of-the-art models as reference
benchmarks for further model developments and evaluations on this dataset. The
dataset is available at https://autolaparo.github.io.Comment: Accepted at MICCAI 202
Stereo Dense Scene Reconstruction and Accurate Localization for Learning-Based Navigation of Laparoscope in Minimally Invasive Surgery
Objective: The computation of anatomical information and laparoscope position
is a fundamental block of surgical navigation in Minimally Invasive Surgery
(MIS). Recovering a dense 3D structure of surgical scene using visual cues
remains a challenge, and the online laparoscopic tracking primarily relies on
external sensors, which increases system complexity. Methods: Here, we propose
a learning-driven framework, in which an image-guided laparoscopic localization
with 3D reconstructions of complex anatomical structures is obtained. To
reconstruct the 3D structure of the whole surgical environment, we first
fine-tune a learning-based stereoscopic depth perception method, which is
robust to the texture-less and variant soft tissues, for depth estimation.
Then, we develop a dense visual reconstruction algorithm to represent the scene
by surfels, estimate the laparoscope poses and fuse the depth maps into a
unified reference coordinate for tissue reconstruction. To estimate poses of
new laparoscope views, we achieve a coarse-to-fine localization method, which
incorporates our reconstructed 3D model. Results: We evaluate the
reconstruction method and the localization module on three datasets, namely,
the stereo correspondence and reconstruction of endoscopic data (SCARED), the
ex-vivo phantom and tissue data collected with Universal Robot (UR) and Karl
Storz Laparoscope, and the in-vivo DaVinci robotic surgery dataset, where the
reconstructed 3D structures have rich details of surface texture with an
accuracy error under 1.71 mm and the localization module can accurately track
the laparoscope with only images as input. Conclusions: Experimental results
demonstrate the superior performance of the proposed method in 3D anatomy
reconstruction and laparoscopic localization. Significance: The proposed
framework can be potentially extended to the current surgical navigation
system
Microstructure and Wear Resistance of TIG Remelted NiCrBSi Thick Coatings
The self-fluxing NiCrBSi coatings with 800 μm thickness were prepared on the surface of AISI1045 steel substrate by plasma spraying. And the remelted coating was obtained using by the tungsten inert gas (TIG) arc process. The microstructure, surface roughness, hardness, phase composition, and wear resistance of the sprayed coating and remelted coating were systematically investigated. The results demonstrate that TIG remelted treatment can significantly eliminate the microscopic defects in thick coating and improve its density. The surface roughness (Ra) of the remelted coating is only 18.9% of the sprayed coating. The hardness of the remelted coating is 26.8% higher than that of the sprayed coating. The main phases in the sprayed coating are changed from γ-Ni, Cr7C3, and Cr2B to γ-Ni, Cr23C6, CrB, Ni3B, and Fe3C. The wear mass loss of the remelted coating is only 17.1% of the sprayed coating. Therefore, a Ni-based thick coating with good wear resistance can be obtained by plasma spraying and remelted technique
Recommended from our members
Nicotinamide mononucleotide adenylyltransferase uses its NAD+ substrate-binding site to chaperone phosphorylated Tau.
Funder: Science and Technology Commission of Shanghai Municipality; FundRef: http://dx.doi.org/10.13039/501100003399Funder: Dr. John T. MacDonald Foundation; FundRef: http://dx.doi.org/10.13039/100010239Tau hyper-phosphorylation and deposition into neurofibrillary tangles have been found in brains of patients with Alzheimer's disease (AD) and other tauopathies. Molecular chaperones are involved in regulating the pathological aggregation of phosphorylated Tau (pTau) and modulating disease progression. Here, we report that nicotinamide mononucleotide adenylyltransferase (NMNAT), a well-known NAD+ synthase, serves as a chaperone of pTau to prevent its amyloid aggregation in vitro as well as mitigate its pathology in a fly tauopathy model. By combining NMR spectroscopy, crystallography, single-molecule and computational approaches, we revealed that NMNAT adopts its enzymatic pocket to specifically bind the phosphorylated sites of pTau, which can be competitively disrupted by the enzymatic substrates of NMNAT. Moreover, we found that NMNAT serves as a co-chaperone of Hsp90 for the specific recognition of pTau over Tau. Our work uncovers a dedicated chaperone of pTau and suggests NMNAT as a key node between NAD+ metabolism and Tau homeostasis in aging and neurodegeneration
PI3Ks Maintain the Structural Integrity of T-Tubules in Cardiac Myocytes
Phosphoinositide 3-kinases (PI3Ks) regulate numerous physiological processes including some aspects of cardiac function. Although regulation of cardiac contraction by individual PI3K isoforms has been studied, little is known about the cardiac consequences of downregulating multiple PI3Ks concurrently.Genetic ablation of both p110α and p110β in cardiac myocytes throughout development or in adult mice caused heart failure and death. Ventricular myocytes from double knockout animals showed transverse tubule (T-tubule) loss and disorganization, misalignment of L-type Ca(2+) channels in the T-tubules with ryanodine receptors in the sarcoplasmic reticulum, and reduced Ca(2+) transients and contractility. Junctophilin-2, which is thought to tether T-tubules to the sarcoplasmic reticulum, was mislocalized in the double PI3K-null myocytes without a change in expression level.PI3K p110α and p110β are required to maintain the organized network of T-tubules that is vital for efficient Ca(2+)-induced Ca(2+) release and ventricular contraction. PI3Ks maintain T-tubule organization by regulating junctophilin-2 localization. These results could have important medical implications because several PI3K inhibitors that target both isoforms are being used to treat cancer patients in clinical trials
Study of and and
We study the decays of and to the final states
and based on a single
baryon tag method using data samples of
and events collected with
the BESIII detector at the BEPCII collider. The decays to
are observed for the first time. The
measured branching fractions of and
are in good agreement with, and much
more precise, than the previously published results. The angular parameters for
these decays are also measured for the first time. The measured angular decay
parameter for , , is found to be negative, different to the other
decay processes in this measurement. In addition, the "12\% rule" and isospin
symmetry in the and and
systems are tested.Comment: 11 pages, 7 figures. This version is consistent with paper published
in Phys.Lett. B770 (2017) 217-22
Observation of in
Using a sample of events recorded with
the BESIII detector at the symmetric electron positron collider BEPCII, we
report the observation of the decay of the charmonium state
into a pair of mesons in the process
. The branching fraction is measured for the first
time to be , where the first uncertainty is
statistical, the second systematic and the third is from the uncertainty of
. The mass and width of the are
determined as MeV/ and
MeV.Comment: 13 pages, 6 figure
Observation of the -Annihilation Decay and Evidence for
We report on the observation of the -annihilation decay and the evidence for with a data sample corresponding to an integrated luminosity of 3.19
fb collected with the BESIII detector at the center-of-mass energy
GeV. We obtain the branching fractions
and , respectively
- …