Real-time position control of concentric tube robots

A novel approach to constructing robots is based on concentrically combining pre-curved elastic tubes. By rotating and extending the tubes with respect to each other, their curvatures interact elastically to position and orient the robot's tip, as well as to control the robot's shape along its length. Since these robots form slender curves, they are well suited for minimally invasive medical procedures. A substantial challenge to their practical use is the real-time solution of their kinematics that are described by differential equations with split boundary equations. This paper proposes a numerically efficient approach to real-time position control. It is shown that the forward kinematics are smooth functions that can be pre-computed and accurately approximated using Fourier series. The inverse kinematics can be solved in real time using root finding applied to the functional approximation. Experimental demonstration of real-time position control using this approach is also described

Design and Control of Concentric-Tube Robots

A novel approach toward construction of robots is based on a concentric combination of precurved elastic tubes. By rotation and extension of the tubes with respect to each other, their curvatures interact elastically to position and orient the robot’s tip, as well as to control the robot’s shape along its length. In this approach, the flexible tubes comprise both the links and the joints of the robot. Since the actuators attach to the tubes at their proximal ends, the robot itself forms a slender curve that is well suited for minimally invasive medical procedures. This paper demonstrates the potential of this technology. Design principles are presented and a general kinematic model incorporating tube bending and torsion is derived. Experimental demonstration of real-time position control using this model is also described.Accepted Manuscrip

CA 19-9 as a serum marker in urothelial carcinoma

Introduction: CA 19-9 is a carbohydrate antigen related to Lewis A blood group antigen. It is well-known marker for pancreatic carcinoma and is being investigated for other malignancies including carcinoma bladder. We evaluated the role of serum CA 19-9 as a tumor marker and correlated its level with tumor stage and grade. Materials and Methods: Seventy-five patients with histologically proven urothelial carcinoma were included in this study as case and 25 healthy volunteers as control. Preoperative 5 ml blood sample was collected. Serum level of CA 19-9 was measured using solid-phase enzyme-linked immunosorbent assay kit. The value of CA19-9 was expressed in U/ml and 37 U/ml was taken as cut-off upper value of normal. Results: The range of CA19-9 in patients of urothelial carcinoma was 2 to 122 U/ml with a mean of 26.33±29.28, while in control, it was 8.48±5.01 U/ml (P<0.001). The sensitivity of CA19-9 was 29%. Serum CA19-9 was significantly elevated in invasive disease in comparison with superficial disease (47.17±34.43 vs 16.53±20.13) (P<0.001). Significantly high proportion of patients with invasive disease had value ≥37 U/ml (14/24 [58.3%] vs 8/51 [15.7%]) with P value <0.001. High proportion of high-grade tumor had raised value, 14/34 (41.25%); all patients with metastatic disease had value more than 37 U/ml. Conclusions: Serum CA19-9 is a marker of aggressiveness of urothelial carcinoma and is almost invariably raised in patients with metastatic disease. Thus, it may be used as a prognostic marker but not as a screening tool due to its low sensitivity

CRISPR-Cas9 RAG2 Correction via Coding Sequence Replacement to Preserve Endogenous Gene Regulation and Locus Structure

Abstract RAG2-SCID is a primary immunodeficiency caused by mutations in Recombination-activating gene 2 (RAG2), a gene intimately involved in the process of lymphocyte maturation and function. ex-vivo manipulation of a patient’s own hematopoietic stem and progenitor cells (HSPCs) using CRISPR-Cas9/rAAV6 gene editing could provide a therapeutic alternative to the only current treatment, allogeneic hematopoietic stem cell transplantation (HSCT). Here we show a first-of-its-kind RAG2 correction strategy that replaces the entire endogenous coding sequence (CDS) to preserve the critical endogenous spatiotemporal gene regulation and locus architecture. Expression of the corrective transgene led to successful development into CD3+TCRαβ+ and CD3+TCRγδ+ T cells and promoted the establishment of highly diverse TRB and TRG repertoires in an in-vitro T-cell differentiation platform. We believe that a CDS replacement technique to correct tightly regulated genes, like RAG2, while maintaining critical regulatory elements and conserving the locus structure could bring safer gene therapy techniques closer to the clinic.</jats:p

The Surgical Assistant Workstation (SAW) in Minimally-Invasive Surgery and Microsurgery

The Surgical Assistant Workstation (SAW) provides a modular, open-source software framework to support rapid prototyping of computer-assisted surgery systems, especially those that benefit from enhanced 3D visualization and user interaction. The framework includes a library of components that can be used to implement master-slave or collaborative robot control systems with support for complex video pipelines and a novel interactive surgical visualization environment. SAW includes standardized interface definitions (e.g., command names and payloads), with the goal of making the framework easily extensible so that developers can add support for their own robotic devices and associated hardware platforms. This paper presents an overview of the component-based architecture, followed by applications (use cases) in the areas of minimally-invasive surgery (MIS), microsurgery, and surgical skill assessment.</jats:p