Double Knot Research Articles

Dual-Point Seawater Temperature Simultaneous Sensing Based on Microfiber Double Knot Resonators

A micro-size optical sensor for simultaneous detection of dual-point seawater temperature based on microfiber double knot resonators (MDKRs) is demonstrated in this paper. To obtain the optimal sensor parameters, the sensing mechanism and spectral characteristics of MDKRs in seawater are investigated theoretically and experimentally. Results show that the MDKRs with short period spectra is more suitable for the simultaneous detection of dual-point seawater temperature, due that it has a long wavelength range and is easy to distinguish resonant wavelengths of two microfiber knot resonators (MKRs). The sensitivities of the cascaded MKRs are −13.86 pm/°C and −5.6 pm/°C, respectively, achieving independent and simultaneous seawater temperature sensing. The sensor proposed here can meet the actual demands of mesoscale ocean phenomena and micro-region detection in seawater, and offer references for developing simple and convenient optical method in ocean detection and other practical application.

Medium and long-term follow-up outcome after arthroscopic repair of type II SLAP lesions with two Loops

Objective To determine the medium-long term functional outcome of arthroscopic repair of type II SLAP lesions with two loops. Methods According to retrospective study, 29 cases patients with arthroscopic repairs of isolated type II SLAP lesions were collected from March 2011 to June 2013, the mean patient age at the time of surgery was 31.8 years(range17 to 47 years). All patients with ground anchor suture, and through double loop knot technology to fix SLAP injury.Visual analogue scale(VAS), Kerlan-Jobe Orthopaedic Clinic(KJOC), Roche Shouder function Score(ROWE) were used to determine the function of shoulder joint.The shoulderjoint range of motion before treatment and post treatment were recorded, shoulder joint mobility was recorded, satisfaction survey was done, compared the preoperative and postoperative data to evaluate its clinical effect. Results All patients were available for follow-up of 2.7-5.2 years.Overall, functional outcome was improved from baseline compared with final follow-up for VAS scores((4.3±1.2) points vs.(1.5±0.8) points, t=5.435, P<0.05), KJOC scores((72.1±4.9) points vs.(92.8±5.4) points, t=5.921, P<0.01), and ROWE scores((54.1±12.4) points vs.(84.3±10.2) points, t=7.326, P<0.01). Only a minority of patients feel pain when they did srenuous exercise.According to satisfaction investigation of patients, patient satisfaction was reported in 89.7%, 3 cases had not good results, they could not return to previous level of play, including 2 cases were athletes, 1 case was not athlete. Conclusion There is no more persistent pain and dysfunction after surgery, a good or excellent medium-long term functional outcome can be anticipated after arthroscopic repair of type II SLAP lesions with two loops. Key words: SLAP lesions; Shoulder joint; Arthroscope; Repair

A moray’s many knots: knot tying behaviour around bait in two species of Gymnothorax moray eel

Being able to tie their body into a knot is beneficial to some moray eels and other cylindrical vertebrates for various reasons, although not all morays’ tie knots. Knot tying can generate leverage for feeding activity by moving the knot up the body, and this leverage may be affected by knot type. Three types of knots are known to have been used by morays’ and this study further elucidates this behaviour and ability. Baited Remote Underwater Videos (BRUVs) were used to compare knot tying between the moray eels Gymnothorax prasinus and Gymnothorax prionodon in the Solitary Islands region, eastern Australia. Gymnothorax prasinus tied more knots overall and more types of knot than G. prionodon (five types vs one type, respectively). Both tied the overhand knot and this was the most common knot used by G. prasinus. The figure of eight knot was used two times more than the double overhand knot, being relatively wider and likely easier to move up the body. Gymnothorax prasinus also tied two undescribed knots, now called the ‘moray knot’ and the ‘morays banana knot’, which have more crossings and are bulkier, increasing potential for generating leverage. However, their uncommon use indicates costs may outweigh benefits of these more complex knots. Lower habitat complexity in deeper waters may influence differences in knot tying as G. prasinus were only recorded shallower than 40 m and G. prionodon mainly deeper. These findings further reveal the utility and complexity of knot tying in moray species and cylindrical vertebrates generally.

The effect of a simple intraprocedural checklist on the task performance of laparoscopic novices

BackgroundSurgical checklists are used for error reduction. Checklists are infrequently applied during procedures and have been limited to lists of procedural steps as aid memoires. We aimed to study the effect of a self-administered checklist on the laparoscopic task performance of novices during a standardized task. MethodsTwenty novices were randomized into 2 equal groups, those receiving paper feedback (control group) and those receiving paper feedback and the checklist (checklist group). Subjects performed laparoscopic double knots, repeated over 5 separate stages. Human reliability assessment technique was used for error analysis. Results2,341 errors were detected during the 5 stages. During the first stage, the errors were not significantly different between the 2 groups. The checklist group committed significantly fewer errors as compared with the control group during all the later 4 stages (P < .01). ConclusionsThe simple intraprocedural checklist significantly improved the laparoscopic task performance and the learning curve of laparoscopic novices.

Isogeometric Analysis of Deformation, Inelasticity and Fracture In Thin-Walled Structures

The basic idea of isogeometric analysis (IGA) is to use splines, which are the functions commonly used in computer-aided design (CAD) to describe the geometry, as the basis function for the analysis as well. A main advantage is that a sometimes elaborate meshing process is by-passed. Another benefit is that spline basis-functions possess a higher-order degree of continuity, which enables a more accurate representation of the stress. Further, the order of continuity of the basis-functions can be reduced locally by knot insertion. This feature can be used to model interfaces and cracks as discontinuities in the displacement field.In order to study failure-mechanisms in thin-walled composite materials, an accurate representation of the full three-dimensional stress field is mandatory. A continuum shell formulation is an obvious choice. Continuum shell elements can be developed based on the isogeometric concept. They exploit NURBS basis functions to construct the mid-surface of the shell. In combination with a higher-order B-spline basis function in the thickness direction a complete three-dimensional representation of the shell is obtained. This isogeometric shell formulation can be implemented in a standard finite element code using Bézier extraction.Weak and strong discontinuities can be introduced in the B-spline function using knot-insertion to model material interfaces and delaminations rigorously as discontinuities in the displacement field. The exact representation of material interfaces vastly improves the accuracy of the through-the- thickness stress field. The ability to provide a double knot insertion enables a straightforward analysis of delamination growth in layered composite shells. Illustrative examples will be given.

Zone II flexor tendon repair using double embedded lasso lock knot suturing technique

Objective To summarize the clinical outcomes of repairing Zone Ⅱflexor digitorum tendon injury using the double embedded lasso lock knot technique. Methods From January 2008 to September 2014, the double embedded lasso lock knot technique was employed to repair Zone Ⅱ flexor digitorum tendon injury in 45 fingers of 37 cases. Postoperatively the treatment outcomes were evaluated by the total active motion (TAM) scale. Results Primary wound healing was achieved in 43 fingers of 35 cases, while 2 fingers in 2 cases has secondary wound healing. Thirty-one cases with 35 fingers had postoperative follow-up ranging from 12 to 17 months, with an average of 13.7 months. According to the TAM scale, results were excellent in 29 fingers, good in 5 fingers, and fair in 1 finger. The overall satisfactory rate was 97.1%. Conclusion The double embedded lasso lock knot technique has good anti-skid and anti-split effect with little suture exposure. It allows early functional exercise to effectively prevent tendon adhesions and thus lead to satisfactory results in repairing Zone Ⅱ flexor digitorum tendon injuries. Key words: Tendon injuries; Treatment outcome; Suture; Lasso lock knot

In Silico Characterization of Double Knot Toxin Binding to TRPV1 Channel

In nature, animals and plants use painful toxins as defensive mechanism against predators or competitors. Most of toxins act as irritants or cause pain by interacting with functional domains of ion channels.A target of these painful toxins is the transient receptor potential vanilloid 1 (TRPV1) which is a cation-selective ion channel expressed in primary sensory neurons. TRPV1 is an pain receptor modulated by multiple noxious stimuli as high temperature (>42°), low pH (< 6) or irritants compounds.The Double Knot toxin (DkTx) from Ornithoctonus huwena spider, is a polypeptide which interacts with the extracellular surface of TRPV1 disturbing the selectivity filter and driving the activation of the channel. Even when interaction surface of TRPV1 and DkTx has been identified by site directed mutagenesis and a cryo-EM structure, the structure of DkTx and its binding mechanism remain unknown. In order to understand the atomic interactions involved in DkTx binding, we build a homology model of DkTx toxin which was subsequently docked to the TRPV1 putative binding surface structure to then performing molecular dynamics simulations. Our results suggest that each domain of DkTx toxin independently interact with a single subunit of the TRPV1 tetramer and these interaction network is strongly stabilized by charged residues in both interacting surfaces.

Extracellular Sodium is Required for Temperature-Dependent Gating in TRPV1 Channels

The TRPV1 channel in sensory neurons integrates pain-producing stimuli, including noxious temperature, acidosis, pungent vanilloid compounds and pro-inflammatory lipids. Measurements of TRPV1 channel activity at extreme positive and negative voltages in the presence of other stimuli suggest that the channel has a unique opening transition that is allosterically modulated by independent stimulus-sensing domains. On the contrary, recently obtained near-atomic resolution structures of TRPV1 in different states suggest that different agonists promote distinct open states, by differentially modulating the inner pore gate or the selectivity filter. Finally, it has been proposed that the opening of the pore may confer the channel with high temperature-sensitivity. Here we show that extracellular sodium ions tune both temperature-dependent activation and inactivation in TRPV1 channels to maintain sensitivity to noxious stimuli at physiological temperatures. Exploration of temperature-dependent activation over a wide range of temperatures in the presence of distinct modulators demonstrates that the gating mechanism involves temperature-sensitive and -insensitive transitions that are allosterically coupled and differentially modified by sodium, pH, vanilloids and tarantula toxins. We observe that the channels exhibit non-maximal open probability and temperature-independent gating in the absence of external sodium or in the presence of double knot tarantula toxin DkTx, indicating that the opening transition is temperature-independent and supporting the modular allosteric view of this channel protein. This unique gating mechanism provides a framework for understanding how the temperature sensitivity of TRPV1 is tuned by a wide array of regulators.

The Late Miocene Hipparion (Equidae, Perissodactyla) fossils from Baogeda Ula, Inner Mongolia, China

New material of Hipparion (Baryhipparion) tchikoicum from Baogeda Ula in Abag, Inner Mongolia, China is described. The latest Miocene (∼6 Ma) occurrence of the species is an important chronological reference for the stratigraphy of Baogeda Ula. Furthermore, the Baogeda Ula Hipparion connects the distribution of this species in the Yushe Basin and Mongolia. The deep ectoflexids of the premolars and the rounded double knots of the lower cheek teeth place the Baogeda Ula specimens in the primitive forms of Hipparion in Eurasia. The two North American species of Hipparion, Hipparion shirleyi and Hipparion tehonense with deep ectoflexids and rounded double knots in the lower premolars, may be the ancestral forms of the subgenus Baryhipparion. Furthermore, their age was much earlier than the first appearance of Baryhipparion in Eurasia, so the period and route of the immigration of North American ancestral forms to Eurasia are still unclear. Nevertheless, the Eurasian expansion of this subgenus is clear: it first appeared in North China during the latest Miocene, and then spread northward to the Mongolian Plateau and Transbaikalia; it migrated westward into Europe through Kazakhstan and Caucasus in the Pliocene; and it survived in Transbaikalia until the Early Pleistocene.

The double knot of technology and business-model innovation in the era of ferment of digital exchanges: The case of OM, a pioneer in electronic options exchanges

The discontinuous shift to an electronic exchange system has been a catalyst for extensive transformation of financial markets during the last decades. Previous research has proposed that there are prohibitive regulatory barriers for de novo entrants with limited resources to introduce discontinuous technological innovations and novel business models in finance. We challenge this notion by studying the techno-social transformative process of the first decade of OM, a Swedish de novo entrant that introduced the world's first commercially successful electronic options exchange and the first for-profit exchange. Our analysis reveals that this entrant had a key role in both the technological and regulatory construction of the new market through a bricolage technological development process and behaved as a proactive corporate political entrepreneur (CPE). The first phase of the era of ferment in electronic exchange technology was characterized by an adaptive techno-social development context that was open for bricolage technological and business-model experimentation. In the second phase, these experimental lessons were connected to a deliberative regulatory process that enabled the entrant to influence the regulatory process. We conclude by suggesting that an entrant's dual roles as a bricolage technological entrepreneur and as a CPE provide an alternative path for resource-constrained entrants to transform capital markets.

How securely is the testicular artery occluded in the spermatic cord by using a ligature?

There are no studies on the ideal ligature technique for the spermatic cord. To compare the maximal resistance pressure in the testicular artery and the maximal tensile forces to produce failure of 2 different ligature techniques used for ligation of the equine spermatic cord. The capabilities of 2 types of ligatures, single knot loop and double knot loop, were assessed using a pressure-resistance test in testicular arteries and with an in vitro mechanical evaluation of the tensile strength by single cycle-to-failure testing. In the pressure-resistance test, the mean ± s.d. peak force at failure of the single knot loop was 354.4 ± 91.7 mmHg and for the double knot loop 303.2 ± 62.0 mmHg. There was no significant difference between the maximal load to failure of the single knot loop and double knot loop technique. The pressure needed for rupture was significantly higher (P = 0.001) than for leakage. The maximal tensile force at failure of the single knot loop was significantly higher than the double knot loop (P = 0.028). There was no significant difference in load elongation properties to failure between the single knot loop and double knot loop. Although no significant differences were obtained in the pressure-resistance test, the single knot loop sustained significantly greater load to failure than the double knot loop in single cycle-to-failure testing. Based on these findings, it would appear that the performance of the single knot loop should be superior to the double knot loop. Both ligature techniques are able to withstand the normal physiological intravascular pressure. The single knot loop has the greater breaking strength of the 2 ligatures tested and is less time consuming to perform and may therefore have advantages during equine castration.

Functional Characterization of the Double Knot Toxin (DkTx) as an Activator of the TRPV1 Ion Channel

The double knot toxin (DkTx), a peptide isolated from the Chinese bird spider venom, activates the TRPV1 ion channel by binding to the channel with high affinity. As its name suggests, DkTx consists of two cystine-rich lobes (K1 and K2) attached to each other via an oligopeptide linker. These lobes belong to the inhibitory cystine knot (ICK) family of peptide toxins that modulate the activity of voltage-gated ion channels. The mechanism by which ICK peptides activate voltage-gated channels have been well-studied and these peptides have served as powerful pharmacological tools for elucidation of the mechanism of ion channel-mediated voltage sensing. It is therefore tempting to speculate that DkTx has the potential to serve as a powerful tool to help elucidate the hitherto elusive mechanisms of activation of TRPV1 by a wide range of stimuli including chemical ligands and temperature. Here, we outline our initial efforts towards achieving this goal. Specifically, we describe the high-yielding production of DkTx from an E. coli expression system and report voltage clamp experiments that yielded dose response curves for TRPV1 activation by DkTx, K1, and K2, thereby revealing the order of potency of the toxins (DkTx>K2>>K1). Moreover, the dose response curve for K2 suggests a much more cooperative binding of the toxin to the channel (Hill coefficient ∼4) as compared to DkTx (Hill coefficient ∼1). To understand the molecular basis of these results, we are currently studying the activation of TRPV1 by mutants of K1, K2, and DkTx.

Cubic subdivision schemes with double knots

We investigate univariate and bivariate binary subdivision schemes based on cubic B-splines with double knots. It turns out that double knots change the behaviour of a uniform cubic scheme from primal to dual. We focus on the analysis of new bivariate cubic schemes with double knots at extraordinary points. These cubic schemes produce C1 surfaces with the original Doo–Sabin weights.

편망 후 열처리 온도가 PBS 모노필라멘트사의 물리적 특성에 미치는 영향

The monofilament with 0.304mm of diameter was produced using a polybutylene succinate (PBS) resin, and a gill net was made by it. We investigated the impact of heat setting temperature on the mechanical properties, knot state and height of gill net. Heat treatment was carried out using the high pressure steam machine for 20 minutes at temperature of <TEX>$55^{\circ}C$</TEX>, <TEX>$60^{\circ}C$</TEX>, <TEX>$70^{\circ}C$</TEX> and <TEX>$75^{\circ}C$</TEX>. Before heat treatment, the strength and elongation of PBS monofilament were estimated to be <TEX>$48.1kg/mm^2$</TEX>, 23.8% at unknot, <TEX>$37.6kg/mm^2$</TEX>, 18.8% at single knot, <TEX>$26.6kg/mm^2$</TEX>, 22.9% at double knot in dry condition, respectively. The strength and elongation of PBS monofilament with double knot were decreased as heat setting temperature increased, and the decreasing rate of strength was showed to be higher than that of elongation. It was not found any differences in strength and elongation of PBS monofilament yarn with double knot at the <TEX>$65^{\circ}C$</TEX> and <TEX>$70^{\circ}C$</TEX> of heat setting temperature by 5% significance of T-test, but there was a significant difference at the <TEX>$70^{\circ}C$</TEX> and <TEX>$75^{\circ}C$</TEX> of heat setting temperature. The net's height and length from leg to leg appeared no differences at the <TEX>$70^{\circ}C$</TEX> and <TEX>$75^{\circ}C$</TEX> of heat setting temperature. In results, it was investigated that the PBS monofilament gill net with the maximized physical properties could be manufactured at <TEX>$70^{\circ}C$</TEX> of heat setting temperature using a high pressure steam machine for 20 minutes.

Smooth Bi-3 spline surfaces with fewest knots

Converting a quadrilateral input mesh into a C 1 surface with one bi-3 tensor-product spline patch per facet is a classical challenge. We give explicit local averaging formulas for the spline control points. Where the quadrilateral mesh is not regular, the patches have two internal double knots, the least number and multiplicity to always allow for an unbiased G 1 construction.

Estudo da resistência do tendão do supra-espinal com pontos simples, duplos e Mason Allen

OBJETIVO: O objetivo do trabalho foi comparar a resistência entre os pontos simples, duplo e Mason-Allen modificado, utilizados para o reparo do manguito rotador, e verificar se há diferença significativa que justifique a utilização do ponto do tipo Mason-Allen modificado ao invés dos pontos simples ou duplo. MÉTODO: Retiramos tendões do músculo supra-espinal de 15 cadáveres humanos frescos (30 ombros), com a média de idade de 45 anos. Os testes foram realizados na máquina universal de ensaio mecânico Kratos® 500/2000 e os resultados submetidos aos testes estatísticos de t-student, análise de variância (ANOVA), comparação múltipla de Bonferroni e calculadas as correlações de Pearson. Os testes foram realizados ao nível de significância de 5%. RESULTADOS: Não houve diferença significativa com relação à idade, ao tamanho das amostras e deslocamento do tendão. A resistência variou com média de 127,50 N com o ponto simples, 163,95 N com o duplo e com o ponto de Mason-Allen modificado esta foi de 198,45 N. CONCLUSÃO: não existe diferença da resistência no tendão quanto à falha na interface sutura - tendão comparando-se o ponto duplo com o Mason-Allen modificado e os pontos simples e duplo, porém há diferença quando comparados os pontos simples e Mason-Allen modificado.

Transfemoral percutaneous removal of a knotted Swan‐Ganz catheter

Intracardiac knotting of balloon-tipped flow-directed catheters during a heart catheterization procedure represents a rare but serious complication. In case that such an event occurs, leading to inability to remove the catheter, various different methods have been described to solve the problem, varying from the least invasive to open heart surgery. The formation of large knots requires surgical removal in the vast majority of cases. We describe the successful nonsurgical removal of a Swan-Ganz catheter, after the formation of a large double knot, during a right heart catheterization performed without fluoroscopic guidance in the intensive care unit. This technique could serve as a last resort in cases that surgical removal seems inevitable due to size-related inapplicability of other nonsurgical methods.

On the complexity of smooth spline surfaces from quad meshes

This paper derives strong relations that boundary curves of a smooth complex of patches have to obey when the patches are computed by local averaging. These relations restrict the choice of reparameterizations for geometric continuity. In particular, when one bicubic tensor–product B-spline patch is associated with each facet of a quadrilateral mesh with n-valent vertices and we do not want segments of the boundary curves forced to be linear, then the relations dictate the minimal number and multiplicity of knots: For general data, the tensor–product spline patches must have at least two internal double knots per edge to be able to model a G 1 -connected complex of C 1 splines. This lower bound on the complexity of any construction is proven to be sharp by suitably interpreting an existing surface construction. That is, we have a tight bound on the complexity of smoothing quad meshes with bicubic tensor–product B-spline patches.

Comparison of mono‐ and bicanalicular silicone stent intubation in dacryocystorhinostomy

Abstract Purpose Silicone stent intubation is used in DCR procedures to prevent a restenosis of the surgical ostium. However, use is not generally accepted due to concers on cost/effectiveness. The goal of our study was to analyze the types and rate of complications associated with monocanalicular and bicanalicular silicones stent intubation nad success rate of DCR procedure. Methods A consecutive series of 114 patients who underwent 120 DCR procedures at our institution from November 2005 on has been included in the study. All DCR (transcanalicular laser DCR’s) procedures were performed under general anaesthesia. One of two types of silicone intubation was inserted at each procedure: bicanalicular silicone stent (72 cases), and inferior monocanalicular stent alone (38 cases). In the former a metallic clip was used to secure the stents in the nasal cavity, in the latter a double knot was applied. The intubation has been removed after 4 months. Results We encountered the following complications: cheese‐wiring of lacrimal punctum (14 cases), prolaps of intubation at the punctual side (9 cases), irritation of conjunctiva (3 cases), corneal erosion (1 case), retention of metallic clip in lacrimal sac (1 case). We statistically analyzed and compared the rate of complications for both types of intubation. Decubitus of the lacrimal punctum was less frequent with monocanalicular intubation compared to bicanalicular intubation; other complications were present at similar rates. Conclusion Complications with silicone stent intubation are not difficult to cope with and normally do not produce adverse effect on DCR success rate with the exception of early and complete prolaps of intubation, which is associated with a lesser success rate of DCR.

Matched asymptotic expansions for twisted elastic knots: A self-contact problem with non-trivial contact topology

We derive solutions of the Kirchhoff equations for a knot tied on an infinitely long elastic rod subjected to combined tension and twist, and held at both endpoints at infinity. We consider the case of simple (trefoil) and double (cinquefoil) knots; other knot topologies can be investigated similarly. The rod model is based on Hookean elasticity but is geometrically nonlinear. The problem is formulated as a nonlinear self-contact problem with unknown contact regions. It is solved by means of matched asymptotic expansions in the limit of a loose knot. We obtain a family of equilibrium solutions depending on a single loading parameter U ¯ (proportional to applied twisting moment divided by square root of pulling force), which are asymptotically valid in the limit of a loose knot, ε → 0 . Without any a priori assumption, we derive the topology of the contact set, which consists of an interval of contact flanked by two isolated points of contacts. We study the influence of the applied twist on the equilibrium.