Accurate human tissue biomechanical data represents a critical knowledge gap that will help facilitate the advancement of new medical devices, patient-specific predictive models, and training ...simulators. Tissues related to the human airway are a top priority, as airway medical procedures are common and critical. Placement of a surgical airway, though less common, is often done in an emergent (cricothyrotomy) or urgent (tracheotomy) fashion. This study is the first to report relevant puncture force data for the human cricothyroid membrane and tracheal annular ligaments. Puncture forces of the cricothyroid membrane and tracheal annular ligaments were collected from 39 and 42 excised human donor tracheas, respectively, with a mechanized load frame holding various surgical tools. The average puncture force of the cricothyroid membrane using an 11 blade scalpel was 1.01 ± 0.36 N, and the average puncture force of the tracheal annular ligaments using a 16 gauge needle was 0.98 ± 0.34 N. This data can be used to inform medical device and airway training simulator development as puncture data of these anatomies has not been previously reported.
Two new macromolecular crystallography (MX) beamlines at the National Synchrotron Light Source II, FMX and AMX, opened for general user operation in February 2017 Schneider et al. (2013). J. Phys. ...Conf. Ser.425, 012003; Fuchs et al. (2014). J. Phys. Conf. Ser.493, 012021; Fuchs et al. (2016). AIP Conf. Proc. SRI2015, 1741, 030006. FMX, the micro‐focusing Frontier MX beamline in sector 17‐ID‐2 at NSLS‐II, covers a 5–30 keV photon energy range and delivers a flux of 4.0 × 1012 photons s−1 at 1 Å into a 1 µm × 1.5 µm to 10 µm × 10 µm (V × H) variable focus, expected to reach 5 × 1012 photons s−1 at final storage‐ring current. This flux density surpasses most MX beamlines by nearly two orders of magnitude. The high brightness and microbeam capability of FMX are focused on solving difficult crystallographic challenges. The beamline's flexible design supports a wide range of structure determination methods – serial crystallography on micrometre‐sized crystals, raster optimization of diffraction from inhomogeneous crystals, high‐resolution data collection from large‐unit‐cell crystals, room‐temperature data collection for crystals that are difficult to freeze and for studying conformational dynamics, and fully automated data collection for sample‐screening and ligand‐binding studies. FMX's high dose rate reduces data collection times for applications like serial crystallography to minutes rather than hours. With associated sample lifetimes as short as a few milliseconds, new rapid sample‐delivery methods have been implemented, such as an ultra‐high‐speed high‐precision piezo scanner goniometer Gao et al. (2018). J. Synchrotron Rad.25, 1362–1370, new microcrystal‐optimized micromesh well sample holders Guo et al. (2018). IUCrJ, 5, 238–246 and highly viscous media injectors Weierstall et al. (2014). Nat. Commun.5, 3309. The new beamline pushes the frontier of synchrotron crystallography and enables users to determine structures from difficult‐to‐crystallize targets like membrane proteins, using previously intractable crystals of a few micrometres in size, and to obtain quality structures from irregular larger crystals.
The new Frontier Microfocus Macromolecular Crystallography beamline FMX in sector 17‐ID‐2 of the National Synchrotron Lightsource II provides an ultra‐bright microfocus beam and a flexible experimental station for structure determination from the most challenging crystals.
Abstract Background Stress urinary incontinence is a significant problem in young female athletes, but the pathophysiology remains unclear because of the limited knowledge of the pelvic floor support ...function and limited capability of currently available assessment tools. The aim of our study is to develop an advanced computer modeling tool to better understand the dynamics of the internal pelvic floor during highly transient athletic activities. Methods Apelvic model was developed based on high-resolution MRI scans of a healthy nulliparous young female. A jump-landing process was simulated using realistic boundary conditions captured from jumping experiments. Hypothesized alterations of the function of pelvic floor muscles were simulated by weakening or strengthening the levator ani muscle stiffness at different levels. Intra-abdominal pressures and corresponding deformations of pelvic floor structures were monitored at different levels of weakness or enhancement. Findings Results show that pelvic floor deformations generated during a jump-landing process differed greatly from those seen in a Valsalva maneuver which is commonly used for diagnosis in clinic. The urethral mobility was only slightly influenced by the alterations of the levator ani muscle stiffness. Implications for risk factors and treatment strategies were also discussed. Interpretation Results suggest that clinical diagnosis should make allowances for observed differences in pelvic floor deformations between a Valsalva maneuver and a jump-landing process to ensure accuracy. Urethral hypermobility may be a less contributing factor than the intrinsic sphincteric closure system to the incontinence of young female athletes.
Chalcogenide films with reversible amorphous-crystalline phase transitions have been commercialized as optically rewritable data-storage media, and intensive effort is now focused on integrating them ...into electrically addressed non-volatile memory devices (phase-change random-access memory or PCRAM). Although optical data storage is accomplished by laser-induced heating of continuous films, electronic memory requires integration of discrete nanoscale phase-change material features with read/write electronics. Currently, phase-change films are most commonly deposited by sputter deposition, and patterned by conventional lithography. Metal chalcogenide films for transistor applications have recently been deposited by a low-temperature, solution-phase route. Here, we extend this methodology to prepare thin films and nanostructures of GeSbSe phase-change materials. We report the ready tuneability of phase-change properties in GeSbSe films through composition variation achieved by combining novel precursors in solution. Rapid, submicrosecond phase switching is observed by laser-pulse annealing. We also demonstrate that prepatterned holes can be filled to fabricate phase-change nanostructures from hundreds down to tens of nanometres in size, offering enhanced flexibility in fabricating PCRAM devices with reduced current requirements.
High throughput screening technologies such as acoustic droplet ejection (ADE) greatly increase the rate at which X-ray diffraction data can be acquired from crystals. One promising high throughput ...screening application of ADE is to rapidly combine protein crystals with fragment libraries. In this approach, each fragment soaks into a protein crystal either directly on data collection media or on a moving conveyor belt which then delivers the crystals to the X-ray beam. By simultaneously handling multiple crystals combined with fragment specimens, these techniques relax the automounter duty-cycle bottleneck that currently prevents optimal exploitation of third generation synchrotrons. Two factors limit the speed and scope of projects that are suitable for fragment screening using techniques such as ADE. Firstly, in applications where the high throughput screening apparatus is located inside the X-ray station (such as the conveyor belt system described above), the speed of data acquisition is limited by the time required for each fragment to soak into its protein crystal. Secondly, in applications where crystals are combined with fragments directly on data acquisition media (including both of the ADE methods described above), the maximum time that fragments have to soak into crystals is limited by evaporative dehydration of the protein crystals during the fragment soak. Here we demonstrate that both of these problems can be minimized by using small crystals, because the soak time required for a fragment hit to attain high occupancy depends approximately linearly on crystal size.
Purpose
Most evaluations of surgical workflow or surgeon skill use simple, descriptive statistics (e.g., time) across whole procedures, thereby deemphasizing critical steps and potentially obscuring ...critical inefficiencies or skill deficiencies. In this work, we examine off-line, temporal clustering methods that chunk training procedures into clinically relevant surgical tasks or steps during robot-assisted surgery.
Methods
Features calculated from the isogony principle are used to train four common machine learning algorithms from dry-lab laparoscopic data gathered from three common training exercises. These models are used to predict the binary or ternary skill level of a surgeon. K-fold and leave-one-user-out cross-validation are used to assess the accuracy of the generated models.
Results
It is shown that the proposed scalar features can be trained to create 2-class and 3-class classification models that map to fundamentals of laparoscopic surgery skill level with median 85 and 63% accuracy in cross-validation, respectively, for the targeted dataset. Also, it is shown that the 2-class models can discern class at 90% of best-case mean accuracy with only 8 s of data from the start of the task.
Conclusion
Novice and expert skill levels of unobserved trials can be discerned using a state vector machine trained with parameters based on the isogony principle. The accuracy of this classification comes within 90% of the classification accuracy from observing the full trial within 10 s of task initiation on average.
Acoustic droplet ejection (ADE) is a powerful technology that supports crystallographic applications such as growing, improving and manipulating protein crystals. A fragment‐screening strategy is ...described that uses ADE to co‐crystallize proteins with fragment libraries directly on MiTeGen MicroMeshes. Co‐crystallization trials can be prepared rapidly and economically. The high speed of specimen preparation and the low consumption of fragment and protein allow the use of individual rather than pooled fragments. The Echo 550 liquid‐handling instrument (Labcyte Inc., Sunnyvale, California, USA) generates droplets with accurate trajectories, which allows multiple co‐crystallization experiments to be discretely positioned on a single data‐collection micromesh. This accuracy also allows all components to be transferred through small apertures. Consequently, the crystallization tray is in equilibrium with the reservoir before, during and after the transfer of protein, precipitant and fragment to the micromesh on which crystallization will occur. This strict control of the specimen environment means that the crystallography experiments remain identical as the working volumes are decreased from the few microlitres level to the few nanolitres level. Using this system, lysozyme, thermolysin, trypsin and stachydrine demethylase crystals were co‐crystallized with a small 33‐compound mini‐library to search for fragment hits. This technology pushes towards a much faster, more automated and more flexible strategy for structure‐based drug discovery using as little as 2.5 nl of each major component.
In 2013, medical error was the third leading cause of death in the United States.
In China, as in the case with the United States, training and assessment are developing as a strategy to reduce the ...occurrence of such errors. The objective of this study was to assess the current state of the use of simulation-based training in Beijing and to explore the barriers to further development.
This study included hospitals in Beijing accredited by the Standardized Residency Training (SRT) program. The questionnaire was designed online and distributed to the SRT management departments by e-mail or instant message.
Thirty hospitals were invited to participate in this survey, and 15 responses were completed and met the inclusion criteria. Task trainers (15/15), full-scale mannequins (14/15), standardized patients (12/15), and virtual reality workstations (11/15) were the most common types of simulation modalities available for use. Among the given specialties for SRT, the availability of simulation courses was 2/2 for pediatric internal medicine, 1/1 for pediatric surgery, 10/11 for surgery, 11/14 for internal medicine, 7/9 for anesthesiology, 6/8 for emergency medicine, and 3/9 for obstetrics/gynecology. Of the 13 institutions with available simulation curricula, 12/13 had simulation focused on proficiency-based skill training, 11/13 had medical knowledge learning, 10/13 had skill competency assessment. The main targeted trainees in these hospitals were residents (or postgraduate residents) and medical students (or interns). The top 2 barriers were the shortage of sustainable financial resources (12/15) and advocacy from their institutional authorities (7/15).
It is evident that there is a need for more development of training facilities, and for training the "trainers" and administrators. Financial funding, curricular design, and research seem to be crucial for building a long-term, sustainable, effective program.
Background
Major vessel injury (MVI) is a dangerous complication associated with laparoscopic surgery that leads, if not properly handled, to blood loss, conversion to open surgery, and eventually ...death. In this paper, we describe the preliminary evaluation of the SimPORTAL MVI model, created with the goal of simulating an intra-corporeal injury to a large vessel.
Methods
For this study, we created MVI models for 17 residents (PGY 1–4). Each resident was asked to perform an intracorporeal knot on a penrose drain within a maximum time limit of 6 min (in accordance with European basic laparoscopic urological skills rules) and then to subsequently repair a vessel injury on the MVI model, which was perfused with synthetic blood, within a maximum blood loss of 3 L. During the vessel repair, low lights and pulse sounds were used to simulate the operating room environment. All participants filled out a survey pre- and post-task to score various aspects of the model.
Results
We successfully created a model that simulates a critical surgical event. None of the participants reported having previous experience repairing a MVI. Six participants were able to perform the intracorporeal knot, and 12 residents (70.5 %) were able to repair the MVI model under the given time and blood loss limits. Eleven participants agreed that the MVI model behaves like a real vessel, and six felt to be capable of performing the task prior to attempting it. Sixteen participants thought that the MVI model should be part of laparoscopic curriculums during residency.
Conclusions
The SimPORTAL MVI model is a feasible low-cost model that would be well appreciated as a part of laparoscopic curriculum for residents. Minor improvements, including pressure measurement in the vessel for task assessment, will be made in the future, and further studies are necessary to definitively validate this model.
Abstract
State-of-the-art tissue analogues used in high-fidelity, hands-on medical simulation modules can deliver lifelike appearance and feel but lack the capability to provide quantified, real-time ...assessment of practitioner performance. The monolithic fabrication of hybrid printed/textile piezoresistive strain sensors in a realistic Y/V plasty suture training pad is demonstrated. A class of 3D-printable organogels comprised of inexpensive and nonhazardous feedstocks is used as the sensing medium, and conductive composite threads are used as the electrodes. These organogels are comprised of a glycol-based deep-eutectic solvent (DES) serving as the ionic conductor and 3-trimethoxysilylmethacrylate-capped fumed silica particles serving as the gelating agent. Rheology measurements reveal the influence of fumed silica particle capping group on the mixture rheology. Freestanding strain sensors demonstrate a maximum strain amplitude of 300%, negligible signal drift, a monotonic sensor response, a low degree of hysteresis, and excellent cyclic stability. The increased contact resistance of the conductive thread electrodes used in place of wire electrodes do not make a significant impact on sensor performance. This work showcases the potential of these organogels utilized in sensorized tissue analogues and freestanding strain sensors for widespread applications in medical simulation and education.
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