We modify the construction of knot Floer homology to produce a one-parameter family of homologies tHFK for knots in S3. These invariants can be used to give homomorphisms from the smooth concordance ...group C to Z, giving bounds on the four-ball genus and the concordance genus of knots. We give some applications of these homomorphisms.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
Knottins, or inhibitor cystine knots (ICKs), are ultra-stable miniproteins with multiple applications in drug design and medical imaging. These widespread and functionally diverse proteins ...are characterized by the presence of three interwoven disulfide bridges in their structure, which form a unique pseudoknot. Since 2004, the KNOTTIN database (www.dsimb.inserm.fr/KNOTTIN/) has been gathering standardized information about knottin sequences, structures, functions and evolution. The website also provides access to bibliographic data and to computational tools that have been specifically developed for ICKs. Here, we present a major upgrade of our database, both in terms of data content and user interface. In addition to the new features, this article describes how KNOTTIN has seen its size multiplied over the past ten years (since its last publication), notably with the recent inclusion of predicted ICKs structures. Finally, we report how our web resource has proved usefulness for the researchers working on ICKs, and how the new version of the KNOTTIN website will continue to serve this active community.
360° virtual reality (VR) video is an exciting and evolving field. Current technology promotes a totally immersive, 3-dimensional (3D), 360° experience anywhere in the world using simply a smart ...phone and virtual reality headset. The potential for its application in the field of surgical education is enormous. The aim of this study was to determine knot tying skills taught with a 360-degree VR video compared to conventional 2D video teaching.
This trial was a prospective, randomised controlled study. 40 foundation year doctors (first year postgraduate) were randomised to either the 360-degree VR video (n = 20) or 2D video teaching (n = 20). Participants were given 15 min to watch their allocated video. Ability to tie a single handed reef knot was then assessed against a marking criteria developed for the Royal College of Surgeons, England, (RCSeng) Basic Surgical Skills (BSS) course, by a blinded assessor competent in knot tying. Each candidate then underwent further teaching using Peyton's four step model. Knot tying technique was then re-assessed.
Knot tying scores were significantly better in the VR video teaching arm when compared with conventional (median knot score 5.0 vs 4.0 p = 0.04). When used in combination with face to face skills teaching this difference persisted (median knot score 9.5 vs 9.0 p = 0.01). More people in the VR arm constructed a complete reef knot than in the 2D arm following face to face teaching (17/20 vs 12/20). No difference between the groups existed in the time taken to construct a reef knot following video and teaching (median time 31.0s vs 30.5s p = 0.89).
This study shows there is significant merit in the application of 360-degree VR video technology in surgical training, both as an independent teaching aid and when used as an adjunct to traditional face to face teaching.
•To determine knot tying skills taught with a 360-degree Virtual Reality video compared to 2- Dimensional video teaching.•Using video teaching alone, knot tying scores were significantly better in the 360-degree Virtual Reality video arm.•More people in the 360-degree Virtual Reality video arm constructed a complete reef knot than in the 2-Dimensional arm.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The extra domain B splice variant (EDB) of human fibronectin selectively expressed in the tumor vasculature is an attractive target for cancer imaging and therapy. Here, we describe the generation ...and characterization of EDB-specific optical imaging probes. By screening combinatorial cystine-knot miniprotein libraries with phage display technology we discover exquisitely EDB-specific ligands that share a distinctive motif. Probes with a binding constant in the picomolar range are generated by chemical oligomerization of selected ligands and fluorophore conjugation. We show by fluorescence imaging that the probes stain EDB in tissue sections derived from human U-87 MG glioblastoma xenografts in mice. Moreover, we demonstrate selective accumulation and retention of intravenously administered probes in the tumor tissue of mice with U-87 MG glioblastoma xenografts by in vivo and ex vivo fluorescence imaging. These data warrants further pursuit of the selected cystine-knot miniproteins for in vivo imaging applications.
Abstract
In the initial version of the article (Klotz and Maldonado 2021
J. Phys. A: Math. Theor.
54
445201), an upper bound on the ropelength of (
p
, 2) torus links was found by considering a helix ...wrapped around a circle. The exact expression for the bound was determined using a small-angle approximation which was unjustified. Here we provide the correct expression, which has the same asymptotic behavior as the original.
Abstract
Background:
The most essential part of arthroscopic shoulder surgery is tying a secure knot. A knot should be a low profile, nonbulky, and more stable construct. In the present research, we ...have compared the biomechanical performance of the new sliding locking knot-the Banarji knot, with two different sliding locking knots: The Samsung Medical Centre (SMC) Knot and the Weston Knot.
Methods:
Two samples of arthroscopic sliding locking knot, Banarji knot with three and five half hitches were taken. They were named Banarji Knots 1 and 2 in the study. The SMC Knot and Weston Knot were taken for comparison with the Banarji Knot. All knots were prepared with high-strength suture material fiber wire (Arthrex, Naples, FL, USA) and were tested in Bose Testing Machine to evaluate the load to failure of knots taken in the research. The statistical significance was determined using a
P
= 0.05.
Results:
The maximum load to failure was higher with the Banarji Knot, and it showed significantly better performance when compared with other knots taken in this study. The maximum load to failure in Banarji Knot 1 was 23% and 17% higher than SMC Knot and Weston groups, respectively, and that for Banarji Knot 2 was 29% and 22% higher than SMC and Weston groups, respectively.
Conclusion:
The Banarji knot is a low-profile, stronger, and stable knot. The biomechanical properties of the Banarji knot were better, and the load to failure was superior to SMC and Weston Knot.
Effects connected with the mathematical theory of knots1 emerge in many areas of science, from physics2,3 to biology4. Recent theoretical work discovered that the braid group characterizes the ...topology of non-Hermitian periodic systems5, where , the complex band energies can braid in momentum space. However, such braids of complex-energy bands have not been realized or controlled experimentally. Here, we introduce a tight-binding lattice model that can achieve arbitrary elements in the braid group of two strands B2. We experimentally demonstrate such topological complex-energy braiding of non-Hermitian bands in a synthetic dimension6,7. Our experiments utilize frequency modes in two coupled ring resonators, one of which undergoes simultaneous phase and amplitude modulation. We observe a wide variety of two-band braiding structures that constitute representative instances of links and knots, including the unlink, the unknot, the Hopf link and the trefoil. We also show that the handedness of braids can be changed. Our results provide a direct demonstration of the braid-group characterization of non-Hermitian topology and open a pathway for designing and realizing topologically robust phases in open classical and quantum systems.
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