•We compared the genetic structure of Macrobathra moth species feeding on Acacia auriculiformis.•Contrasting patterns of genetic structure were found across the four species.•Our results suggest that ...there may be host-specific cryptic species within two species.•Our results illustrate how initial genetic screening can be used to direct future biological control surveys.
Acacia auriculiformis is a native Australian tree that has now become a category 1 invasive weed in Florida, USA. Previous research has identified Macrobathra moths as potential biological control agents for this weed, but little is known about the genetic diversity and structuring of these moths. In this study, we compared the genetic structure of four common Macrobathra moth species across the geographic distribution of A. auriculiformis and across regions where A. auriculiformis does not occur to assess whether any of these moth species may comprise unrecognised cryptic species. We found contrasting patterns of genetic structuring among the four moth species, indicating that host-specific cryptic species could be present in Macrobathra arrectella and M. diplochrysa. Furthermore, we identified a deep genetic disjunction in both M. arrectella and M. callipetala across the Gulf of Carpentaria, a pattern that is also found in A. auriculiformis. The geographic distribution and host plant associations of the distinct mitochondrial lineages of each of these moth species should be further evaluated with additional ecological sampling, and the species status of these lineages tested directly, using additional molecular screening and/or carefully designed cross-mating tests.
To realize a higher-level autonomy of surgical knot tying in minimally invasive surgery (MIS), automated suture grasping, which bridges the suture stitching and looping procedures, is an important ...yet challenging task needs to be achieved. This paper presents a holistic framework with image-guided and automation techniques to robotize this operation even under complex environments. The whole task is initialized by suture segmentation, in which we propose a novel semi-supervised learning architecture featured with a suture-aware loss to pertinently learn its slender information using both annotated and unannotated data. With successful segmentation in stereo-camera, we develop a Sampling-based Sliding Pairing (SSP) algorithm to online optimize the suture's 3D shape. By jointly studying the robotic configuration and the suture's spatial characteristics, a target function is introduced to find the optimal grasping pose of the surgical tool with Remote Center of Motion (RCM) constraints. To compensate for inherent errors and practical uncertainties, a unified grasping strategy with a novel vision-based mechanism is introduced to autonomously accomplish this grasping task. Our framework is extensively evaluated from learning-based segmentation, 3D reconstruction, and image-guided grasping on the da Vinci Research Kit (dVRK) platform, where we achieve high performances and successful rates in perceptions and robotic manipulations. These results prove the feasibility of our approach in automating the suture grasping task, and this work fills the gap between automated surgical stitching and looping, stepping towards a higher-level of task autonomy in surgical knot tying. Note to Practitioners-This paper aims to automate the suture grasping task in surgical knot tying by leveraging stereo visual guidance. To effectively robotize this procedure, it requires multidisciplinary knowledge to achieve suture segmentation, 3D shape reconstruction, and reliable automated grasping, while there are no existing works tackling this procedure especially using robots with RCM kinematics constraints and under complex environments. In this article, we propose a learning-driven method along with a 3D shape optimizer, which can conduct the suture segmentation and output its accurate spatial coordinates, serving as guidance for automated grasping operation. Apart from this, we introduce a unified function to optimize the grasping pose, and a vision-based grasping strategy is also proposed to intelligently complete this task. The experiments extensively validate the feasibility of our framework for automated suture grasp, and its successful completion can serve as a basis for the following looping manipulation, hence filling a step gap in robot-assisted knot tying. This framework can be also encapsulated into the medical robotic system, and by simply indicating (e.g. mouse click) the rough position of the suture's tip in one camera frame, the overall framework can be initialized and further accomplish the suture grasping task, which further prompts a full autonomy of surgical knot tying in the near future.
Knot grasping, folding, and re-grasping Wang, Weifu; Balkcom, Devin
The International journal of robotics research,
02/2018, Letnik:
37, Številka:
2-3
Journal Article
Recenzirano
This paper analyzes the physical resources necessary and sufficient to tie a knot of given structure. We present the first sufficient bound on the number of fingers required to tie a given knot; the ...bound is linear in the number of crossings appearing in the knot diagram for a given knot. We also present a lower bound on the required number of fingers, under a particular model of knot tying. We study how many re-grasps are sufficient to tie an arbitrary knot, and present an algorithm that can yield a small sufficient number of re-grasps to tie the given knot. Physical experiments in which different knots are tied and untied by robots, alone and in collaboration with a human, serve as a proof of concept to show the simplicity and correctness of the approach.
While fast folding of small proteins has been relatively well characterized by experiments and theories, much less is known for slow folding of larger proteins, for which recent experiments suggested ...quite complex and rich folding behaviors. Here, we address how the energy landscape theory can be applied to these slow folding reactions. Combining the perfect-funnel approximation with a multiscale method, we first extended our previous atomic-interaction based coarse grained (AICG) model to take into account local flexibility of protein molecules. Using this model, we then investigated the energy landscapes and folding routes of two proteins with complex topologies: a multidomain protein adenylate kinase (AKE) and a knotted protein 2ouf-knot. In the AKE folding, consistent with experimental results, the kinetic free energy surface showed several substates between the fully unfolded and native states. We characterized the structural features of these substates and transitions among them, finding temperature-dependent multiroute folding. For protein 2ouf-knot, we found that the improved atomic-interaction based coarse-grained model can spontaneously tie a knot and fold the protein with a probability up to 96%. The computed folding rate of the knotted protein was much slower than that of its unknotted counterpart, in agreement with experimental findings. Similar to the AKE case, the 2ouf-knot folding exhibited several substates and transitions among them. Interestingly, we found a dead-end substate that lacks the knot, thus suggesting backtracking mechanisms.
Orchiectomy with a vas deferens to pampiniform plexus ligation (VPL) is a novel method, and it is unclear how its short-term outcomes compare with the results of a conventional method, spermatic cord ...ligation (SCL).
To compare the short-term outcomes of SCL and VPL on inflammation, surgery time, bleeding, pain and surgeon satisfaction during canine open orchiectomy.
Thirty male crossbred dogs undergoing open orchiectomy were enrolled the study. Dogs were randomly allocated to one of the SCL or VPL groups, with 15 patients in each. In the SCL group, the spermatic cord was ligated using absorbable sutures. The vas deferens, and pampiniform plexus self-tying were performed in the VPL group. Surgery time, bleeding and surgeon satisfaction scores were recorded. Inflammation at the surgical site was assessed using infrared thermal camera over three days, and pain associated with inflammation was scored on the third day.
On Day 3, the average temperature in the SCL group was significantly higher than that of the VPL group, with a mean difference of 4.63°C (95% CI: 2.34-6.93, p < 0.001). Moreover, the surgery time in the VPL group was significantly longer compared to the SCL group, with a mean difference of 1.7 min (95% CI: 0.28-3.11, p = 0.021). The bleeding score was also significantly higher in the VPL group (p = 0.012). On the other hand, surgeon satisfaction and pain scores were not significantly different between groups.
Both SCL and VPL methods are safe and effective for orchiectomy in dogs. VPL is comparable in efficacy and safety and has the additional benefit of less inflammation.
The treatment of unstable (Neer type IIB and V) extra-articular distal clavicle fractures remains challenging, especially when encountering a small lateral fragment which does not allow for ...sufficient screw purchase. It was the purpose of this study to present the clinical and radiologic outcome of a consecutive series of patients treated by a stand-alone coracoclavicular stabilization using a so-called cow-hitch technique with a suture anchor.
Nineteen patients were treated with a specific surgical technique for distal clavicle fractures (11 left, 8 right) with either rupture or bony avulsion of the coracoclavicular ligaments. Fourteen patients were examined in our outpatient clinic for the purpose of this study after a mean follow-up of 5 years (1-12.2 years). The examination included scoring according to Constant Murley score (CMS), the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), the Subjective Shoulder Value (SSV), and follow-up radiographs. Two additional patients were amenable to a telephone interview.
All patients reported very good subjective results, with a mean SSV of 92% and a mean ASES score of 96%. The CMS resulted in average absolute values of 92 points. Fractures consolidated in 95% of cases. One patient developed an asymptomatic pseudarthrosis. The coracoclavicular distance was restored from 21 mm preoperatively to 11 mm at the final follow-up and finally showed an average side-to-side difference of +1.8 mm. Sports activities were fully resumed after an average of 4.7 months.
The coracoclavicular stand-alone cow-hitch suture repair for unstable distal clavicle fractures is a minimally invasive fixation technique without prominent hardware that allows for an anatomic reduction and stable fixation with a low complication and high bony union rate. Both radiographic and clinical long-term results are very satisfactory.
Most major platforms sell many of their own products, which typically results in direct competition between the platform and its own business users. A firm may exploit its control of a dominant ...platform to undermine competition in adjacent product markets, such as by excluding competitors from the platform or making their product listings hard to find. Alternatively, it might engage in milder acts of "self-preferencing," such as ranking its own products first in search results. In American antitrust law, antiquated legal doctrine generally places these acts within a special class of unilateral conduct that is almost impossible to challenge. Thus, existing antitrust law does almost nothing to prevent platforms from excluding rivals in adjacent markets, so long as they do so through unilateral conduct. This Article suggests a new antitrust framework for policing unilateral platform conduct in a practicable way that is consistent with antitrust principles. When it is anticompetitive, the conduct in question typically raises the same concerns as the tying arrangement in the famous Microsoftcase-namely, that a vertically integrated firm is exploiting a dominant platform to foreclose rivals in an adjacent market. As such, courts should evaluate most unilateral platform conduct under a revised liability standard that resembles the one applied in Microsoft, rather than the idiosyncratic and inapposite rules applied under existing law. After sketching out the basic proposal, the bulk of the Article focuses on applying it to real-world cases, such as analyzing foreclosure, defining markets, overcoming proof difficulties, and evaluating potential defenses.
Our research group has been focusing on the automation of string tying-untying operations by a robot. In this paper, shape abstraction data of a string named Face-list and an operation planning ...method with Face-list are proposed. In our planning method, string deformation is represented as a state transition of known topology representation P-data and proposed shape abstraction data Face-list. Face-list enables a robot to decide shape operations that can correctly generate a string deformation plan toward the target shape. In addition, an optimal current operation for changing the string toward the target shape is decided based on scoring the difficulty of total shape operations. The results of two experiments using the proposed method are reported in the final.
Background
Laparoscopic suturing and knot tying is essential for advanced laparoscopic procedures and requires training outside of the operating room. However, personal instruction by experienced ...surgeons is limitedly available. To address this, the concept of combining e-learning with practical training has become of interest. This study aims to investigate the influence of the first-person perspective in instructional videos, as well as the feasibility of a completely self-directed training curriculum for laparoscopic suturing and knot tying.
Materials and methods
Ninety-one laparoscopically naïve medical students were randomised into two groups training with e-learning videos in either the first-person perspective (combining endoscopic view and view of hands/instruments/forearm motion) or the endoscopic view only. Both groups trained laparoscopic suturing and knot tying in teams of two until reaching predefined proficiency levels. Blinded, trained raters regularly assessed the participants’ performance by using validated checklists. After training, participants filled out questionnaires regarding training experience and personal characteristics.
Results
Average training time to reach proficiency did not differ between groups first-person perspective (min): 112 ± 44; endoscopic view only (min): 109 ± 47;
p
= 0.746. However, participants from both groups perceived the first-person perspective as useful for learning new laparoscopic skills. Both groups showed similar baseline performances and improved significantly after training Objective Structured Assessment of Technical Skills (OSATS) (max. 37 points): first-person perspective: 30.3 ± 2.3; endoscopic view only: 30.8 ± 2.3. All participants managed to reach proficiency, needing 8–43 attempts without differences between groups. Visuospatial abilities (mental rotation) seemed to enhance the learning curve.
Conclusion
Modifying instructional videos to the first-person perspective did not translate into a better performance in this setting but was welcomed by participants. Completely self-directed training with the use of e-learning can be a feasible training approach to achieve technical proficiency in laparoscopic suturing and knot tying in a training setting.
AbstractHigh prevalence of musculoskeletal disorders among construction workers pose challenges to the productivity and occupational health of the construction industry. To mitigate the risk of ...musculoskeletal disorders, construction managers need to deepen their understanding of the physical and biomechanical demands of various construction tasks so that appropriate policies and preventive measures can be implemented. Among various construction trades, rebar workers are highly susceptible to lower-back disorders (LBDs) given the physically demanding nature of their work tasks. In particular, rebar tying is considered to be closely related to LBDs because it exposes workers to multiple ergonomic risk factors (repetitive works in prolonged static and awkward postures). The objective of the current study was to compare the differences in lumbar biomechanics during three typical rebar tying postures: stooping, one-legged kneeling, and squatting. Biomechanical variables including trunk muscle activity and trunk kinematics were measured by surface electromyography and motion sensors, respectively. Ten healthy male participants performed a simulated rebar tying task in each of the three postures in a laboratory setting. Repeated measures analysis of variance showed that while each posture has its unique trunk kinematic characteristics, all these postures involved excessive trunk inclination that exceeded the internationally recommended trunk inclination angle of 60° for static working postures. Of the three postures, stooping posture demonstrated a significant reduction in electromyographic activity of lumbar muscles (a reduction in 60–80% of muscle activity as compared to the other two postures). The reduced muscle activity may shift the loading to passive spinal structures (e.g., spinal ligaments and joint capsules), which is known to be a risk factor for LBD development. Collectively, the results from this study may help explain the high prevalence of LBDs in rebar workers. Future studies are warranted to confirm the findings at construction sites and to develop appropriate ergonomic approaches for rebar workers.
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