5,777 research outputs found
Interaction Replica: Tracking human-object interaction and scene changes from human motion
Humans naturally change their environment through interactions, e.g., by
opening doors or moving furniture. To reproduce such interactions in virtual
spaces (e.g., metaverse), we need to capture and model them, including changes
in the scene geometry, ideally from egocentric input alone (head camera and
body-worn inertial sensors). While the head camera can be used to localize the
person in the scene, estimating dynamic object pose is much more challenging.
As the object is often not visible from the head camera (e.g., a human not
looking at a chair while sitting down), we can not rely on visual object pose
estimation. Instead, our key observation is that human motion tells us a lot
about scene changes. Motivated by this, we present iReplica, the first
human-object interaction reasoning method which can track objects and scene
changes based solely on human motion. iReplica is an essential first step
towards advanced AR/VR applications in immersive virtual universes and can
provide human-centric training data to teach machines to interact with their
surroundings. Our code, data and model will be available on our project page at
http://virtualhumans.mpi-inf.mpg.de/ireplica
Cas3 Protein—A Review of a Multi-Tasking Machine
Cas3 has essential functions in CRISPR immunity but its other activities and roles, in vitro and in cells, are less widely known. We offer a concise review of the latest understanding and questions arising from studies of Cas3 mechanism during CRISPR immunity, and highlight recent attempts at using Cas3 for genetic editing. We then spotlight involvement of Cas3 in other aspects of cell biology, for which understanding is lacking—these focus on CRISPR systems as regulators of cellular processes in addition to defense against mobile genetic element
Autonomously Navigating a Surgical Tool Inside the Eye by Learning from Demonstration
A fundamental challenge in retinal surgery is safely navigating a surgical
tool to a desired goal position on the retinal surface while avoiding damage to
surrounding tissues, a procedure that typically requires tens-of-microns
accuracy. In practice, the surgeon relies on depth-estimation skills to
localize the tool-tip with respect to the retina in order to perform the
tool-navigation task, which can be prone to human error. To alleviate such
uncertainty, prior work has introduced ways to assist the surgeon by estimating
the tool-tip distance to the retina and providing haptic or auditory feedback.
However, automating the tool-navigation task itself remains unsolved and
largely unexplored. Such a capability, if reliably automated, could serve as a
building block to streamline complex procedures and reduce the chance for
tissue damage. Towards this end, we propose to automate the tool-navigation
task by learning to mimic expert demonstrations of the task. Specifically, a
deep network is trained to imitate expert trajectories toward various locations
on the retina based on recorded visual servoing to a given goal specified by
the user. The proposed autonomous navigation system is evaluated in simulation
and in physical experiments using a silicone eye phantom. We show that the
network can reliably navigate a needle surgical tool to various desired
locations within 137 microns accuracy in physical experiments and 94 microns in
simulation on average, and generalizes well to unseen situations such as in the
presence of auxiliary surgical tools, variable eye backgrounds, and brightness
conditions.Comment: Accepted to ICRA 202
Multimodality Treatment for Early-Stage Hepatocellular Carcinoma: A Bridging Therapy for Liver Transplantation
Purpose: To evaluate the efficiency of a multimodality approach consisting of transcatheter arterial chemoembolization (TACE) and radiofrequency ablation (RFA) as bridging therapy for patients with hepatocellular carcinoma (HCC) awaiting orthotopic liver transplantation (OLT) and to evaluate the histopathological response in explant specimens. Materials and Methods: Between April 2001 and November 2011, 36 patients with 50 HCC nodules (1.4-5.0 cm, median 2.8 cm) on the waiting list for liver transplantation were treated by TACE and RFA. The drop-out rate during the follow-up period was recorded. The local efficacy was evaluated by histopathological examination of the explanted livers. Results: During a median follow-up time of 29 (4.0-95.3) months the cumulative drop-out rate for the patients on the waiting list was 0, 2.8, 5.5, 11.0, 13.9 and 16.7% at 3, 6, 12, 24, 36 and 48 months, respectively. 16 patients (with 26 HCC lesions) out of 36(44.4%) were transplanted by the end of study with a median waiting list time of 13.7 (2.5-37.8) months. The histopathological examination of the explanted specimens revealed a complete necrosis in 20 of 26 HCCs (76.9%), whereas 6 (23.1%) nodules showed viable residual tumor tissue. All transplanted patients are alive at a median time of 29.9 months. Imaging correlation showed 100% specificity and 66.7% sensitivity for the depiction of residual or recurrent tumor. Conclusion: We conclude that TACE.combined with RFA could provide an effective treatment to decrease the drop-out rate from the OLT waiting list for HCC patients. Furthermore, this combination therapy results in high rates of complete tumor necrosis as evaluated in the histopathological analysis of the explanted livers. Further randomized trials are needed to demonstrate if there is a benefit in comparison with a single-treatment approach. copyright (C) 2012 S. Karger AG, Base
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Shear stress regulation of miR-93 and miR-484 maturation through nucleolin.
Pulsatile shear (PS) and oscillatory shear (OS) elicit distinct mechanotransduction signals that maintain endothelial homeostasis or induce endothelial dysfunction, respectively. A subset of microRNAs (miRs) in vascular endothelial cells (ECs) are differentially regulated by PS and OS, but the regulation of the miR processing and its implications in EC biology by shear stress are poorly understood. From a systematic in silico analysis for RNA binding proteins that regulate miR processing, we found that nucleolin (NCL) is a major regulator of miR processing in response to OS and essential for the maturation of miR-93 and miR-484 that target mRNAs encoding KrĂĽppel-like factor 2 (KLF2) and endothelial nitric oxide synthase (eNOS). Additionally, anti-miR-93 and anti-miR-484 restore KLF2 and eNOS expression and NO bioavailability in ECs under OS. Analysis of posttranslational modifications of NCL identified that serine 328 (S328) phosphorylation by AMP-activated protein kinase (AMPK) was a major PS-activated event. AMPK phosphorylation of NCL sequesters it in the nucleus, thereby inhibiting miR-93 and miR-484 processing and their subsequent targeting of KLF2 and eNOS mRNA. Elevated levels of miR-93 and miR-484 were found in sera collected from individuals afflicted with coronary artery disease in two cohorts. These findings provide translational relevance of the AMPK-NCL-miR-93/miR-484 axis in miRNA processing in EC health and coronary artery disease
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