Symmetric Motion Research Articles

DRAG ON A POROUS SPHERE ENCLOSED IN A SOLID CORE EMBEDDED IN COUPLE STRESS FLUID

In this paper, the problem of steady and axisymmetrical creeping flow of couple stress fluid past a permeable sphere enclosed by a solid core is analyzed. The continuous case of normal velocity and tangential velocity, stress jump boundary condition, and couple stress to be vanishing conditions are applied on the surface of the porous sphere, and the nonpenetrability boundary condition is applied for solid sphere. The problem is expressed by using the Stokes and Brinkman equations, which describe both the flow outside and inside the porous sphere, respectively. Expressions for the couple stress tensor and velocity fields are obtained in terms of Gegenbauer polynomials and Macdonald functions. Both the pressure distribution and the stream function solution for the axially symmetric motion are explicitly solved. An analytical determination for the flow field in terms of stream function is examined by wielding the method of separation of variables. The drag force felt by a permeable sphere due to the external and internal flow is calculated. The impact of the viscosity coefficients and couple stress parameter on drag is investigated numerically, and the findings are displayed in graphical form. The findings show that the uniform flow of a couple stress fluid past a porous sphere enclosed by a solid core with stress jump condition has less drag than the flow of a couple stress fluid through a porous sphere with continuous case of shear stress, and the presence of stress jump coefficients reduces the drag force, pressure, and couple stresses. With reference to earlier, well-known cases, some unique cases of flow past a porous sphere have been validated.

On the dynamics of a 2-DOF nonlinear vibratory system with bistable characteristic and circulatory forces

We consider an autonomous damped 2-DOF mechanical system in which the two DOFs are coupled by a linear spring. A circulatory force is introduced into the system that may result in self-excited vibrations. A nonlinearity is added in the form of a cubic spring so that there are three fixed points, two of them are stable without the circulatory force, i.e., a bistable behavior. The basins of attraction for different values of the circulatory forces are numerically studied to see how the patterns of them change. Using a Poincaré map, the basins of attraction have three dimensions and they are cut with further cross-sections for the ease of visualization. The results are usually complicated maps with non-smooth boundaries, except when the circulatory force uncouples one DOF from the other. Special patterns of the maps are seen when in the nonlinear case a stable limit cycle is about to occur. Even in the case without stable limit cycle, initial conditions within the special range may lead to numerous cycles of periodic-like transient motion before asymptotically converging to a stable fixed point. Phase planes and bifurcation diagrams are also used, and multiple coexisting periodic solutions are found. Some interesting phenomena are also found in the supercritical region, including a restabilized motion that coexists with the associated period-doubled motion, and strong symmetric and asymmetric autonomous bursting-like motions.

Reflection principle for finite-velocity random motions

AbstractWe present a reflection principle for a wide class of symmetric random motions with finite velocities. We propose a deterministic argument which is then applied to trajectories of stochastic processes. In the case of symmetric correlated random walks and the symmetric telegraph process, we provide a probabilistic result recalling the classical reflection principle for Brownian motion, but where the initial velocity has a crucial role. In the case of the telegraph process we also present some consequences which lead to further reflection-type characteristics of the motion.

The advantage of the combined use of intraoperative neuromonitoring and percutaneous ultrasonography of the larynx as a screening for postoperative vocal cord paresis

Background. One of the most common complications during thyroid surgery after hypoparathyroidism is a violation of the mobility of the vocal folds - paresis or paralysis of the larynx. The incidence of damage to the recurrent laryngeal nerves during primary surgical interventions can vary from 1 to 30%. Intraoperative neuromonitoring is the most effective method to reduce the amount of damage to the laryngeal nerves during surgical interventions on the thyroid and parathyroid glands. Assessment of the state of the vocal cords in the preoperative and postoperative period is crucial. In the preoperative period, this helps establish baseline characteristics and identify pre-existing laryngeal paresis, while postoperative early identification of vocal cord paresis helps develop a rapid treatment plan. Indirect laryngoscopy is still considered the reference standard for vocal cord examination. The main advantage is the ability to visualize the vocal cords in 99% of cases. However, this is an invasive procedure that can be painful and uncomfortable for patients, and increases medical costs and lead time.Materials and methods. The results of intraoperative neuromonitoring were analyzed in 25 patients who underwent total thyroidectomy according to indications (diffuse nodular non-toxic goiter — 17 patients (68%), diffuse nodular toxic goiter — 4 patients (16%), autoimmune thyroiditis, diffuse — nodular form — 4 patients (16%)), from September 2021 to February 2022. The patients’ age ranged from 18 to 73 years. There were 23 women (92%), men — 2 (8%). In the study, a C2 neuromonitor (InoMed, Germany), an electrode for EMG recording on an endotracheal tube, and a bipolar forked stimulating probe were used. To assess the mobility of the vocal folds, all patients underwent percutaneous ultrasonography before and after thyroid surgery.Results and discussion. In 20 patients (80%) before surgery on transcutaneous ultrasound of the larynx, the visualization of the structures of the larynx was good (grade 4-5), in 2 male patients (8%), the visualization of the structures of the larynx was satisfactory (grade 3), in 3 women (older than 45 years (12%)) — visualization of the structures of the larynx was satisfactory (grade 3), in all 25 patients (100%) — complete or normal symmetrical movement of the vocal folds (grade I). During the performance of precision extrafascial thyroidectomy in 3 patients (12%), a decrease in the amplitude of oscillations was recorded during stimulation of the left recurrent laryngeal nerve and the left vagus nerve, in order to prevent bilateral paresis of the larynx, it was decided to confine ourselves to hemithyroidectomy followed by a staged right-sided hemithyroidectomy. A day after the performed left-sided hemithyroidectomy, percutaneous ultrasound of the larynx in 2 patients showed a violation of the mobility of the vocal fold on the left (grade II), in 1 patient — symmetrical movement of the vocal folds (grade I) — a false positive reaction. In 22 patients (88%) who underwent total thyroidectomy on percutaneous ultrasound of the larynx, complete or normal symmetrical movement of the vocal folds (I degree).Conclusion. Intraoperative neuromonitoring is an effective tool to localize the recurrent laryngeal nerves regardless of whether a loss of signal (LOS) has occurred, as well as to determine the type of LOS (LOS 1, LOS 2) and staged thyroidectomy in the presence of LOS. Percutaneous vocal cord ultrasonography is currently an effective screening tool, saving 80% of patients from unnecessary invasive laryngoscopy. The complex of these methods should be an obligatory component in surgical interventions on the thyroid and parathyroid glands.

Smile Reanimation with Masseteric-to-Facial Nerve Transfer plus Cross-Face Nerve Grafting in Patients with Segmental Midface Paresis: 3D Retrospective Quantitative Evaluation

Facial paresis involves functional and aesthetic problems with altered and asymmetric movement patterns. Surgical procedures and physical therapy can effectively reanimate the muscles. From our database, 10 patients (18–50 years) suffering from unilateral segmental midface paresis and rehabilitated by a masseteric-to-facial nerve transfer combined with a cross-face facial nerve graft, followed by physical therapy, were retrospectively analyzed. Standardized labial movements were measured using an optoelectronic motion capture system. Maximum teeth clenching, spontaneous smiles, and lip protrusion (kiss movement) were detected before and after surgery (21 ± 13 months). Preoperatively, during the maximum smile, the paretic side moved less than the healthy one (23.2 vs. 28.7 mm; activation ratio 69%, asymmetry index 18%). Postoperatively, no differences in total mobility were found. The activity ratio and the asymmetry index differed significantly (without/with teeth clenching: ratio 65% vs. 92%, p = 0.016; asymmetry index 21% vs. 5%, p = 0.016). Postoperatively, the mobility of the spontaneous smiles significantly reduced (healthy side, 25.1 vs. 17.2 mm, p = 0.043; paretic side 16.8 vs. 12.2 mm, p = 0.043), without modifications of the activity ratio and asymmetry index. Postoperatively, the paretic side kiss movement was significantly reduced (27 vs. 19.9 mm, p = 0.028). Overall, the treatment contributed to balancing the displacements between the two sides of the face with more symmetric movements.

Group-based bi-directional recurrent wavelet neural network for efficient video super-resolution (VSR)

Video super-resolution (VSR) is an important technology for enhancing the quality of video frames. The recurrent neural network (RNN)-based approach is suitable for sequential data because it can use accumulated temporal information. However, since existing methods only tend to capture slow and symmetrical motion with low frame rate, there are still limitations to restore the missing details for more dynamic motion. Most of the previous methods using spatial information treat different types of the spatial features identically. It leads to lack of obtaining meaningful information and enhancing the fine details. We propose a group-based bi-directional recurrent wavelet neural network (GBR-WNN) to exploit spatio-temporal information effectively. The proposed group-based bi-directional RNN (GBR) framework is built on the well-structured process with the group of pictures (GOP). In a GOP, we resolves the low-resolution (LR) frames from border frames to center target frame. Because super-resolved features in a GOP are cumulative, neighboring features are improved progressively and asymmetrical motion can be dealt with. Also, we propose a temporal wavelet attention (TWA) adopting attention module for both spatial and temporal features simultaneously based on discrete wavelet transform. Experiments show that the proposed scheme achieves superior performance compared with state-of-the-art methods.

Which is a better management for vocal fold cyst: cold knife or laser resection?

BackgroundThe objective of the study is to compare the conventional microlaryngeal surgery and the CO2 laser in the treatment of cysts of vocal folds, regarding the postoperative quality of voice.This study was conducted on 53 cases with vocal fold cysts. The cases were randomly allocated into two groups: group 1 (27 cases) was operated by the conventional technique, and group 2 (26 cases) was operated with CO2 laser microlaryngeal operation. At 3-month postoperative, evaluation was done by stroboscopic evaluation of vocal folds, grade of hoarseness, roughness, breathiness, asthenia, and strain (GRBAS) scale and Arabic version of Voice Handicap Index (VHI).ResultsThe stroboscope assessment revealed that glottic closure was complete, symmetrical motion, the reappearance of the mucosal wave, normal amplitude, and periodicity in all patients. There is insignificantly different between either group as regards the postoperative scores on VHI and GRBAS scale.ConclusionThere is insignificantly different when comparing laser to conventional microlaryngeal surgery for excision of vocal fold cysts regarding the quality of voice.

Circulating Marangoni flows within droplets in smectic films.

We present a theoretical study and numerical simulation of Marangoni convection within ellipsoidal isotropic droplets embedded in free-standing smectic films (FSSFs). The thermocapillary flows are analyzed for both isotropic droplets spontaneously formed in FSSF overheated above the bulk smectic-isotropic transition and oil lenses deposited on the surface of the smectic film. The realistic model for which the upper drop interface is free from the smectic layers, while at the lower drop surface the smectic layering persists is considered in detail. For isotropic droplets and oil lenses this leads effectively to a sticking of fluid motion at the border with a smectic shell. The above mentioned asymmetric configuration is realized experimentally when the temperature of the upper side of the film is higher than at the lower one. The full set of stationary solutions for Stokes stream functions describing the Marangoni convection flows within the ellipsoidal drops are derived analytically. The temperature distribution in the ellipsoidal drop and the surrounding air is determined in the frame of the perturbation theory. As a result, the analytical solutions for the stationary thermocapillary convection are obtained for different droplet ellipticity ratios and the heat conductivity of the liquid crystal and air. In parallel, the numerical hydrodynamic calculations of the thermocapillary motion in drops are made. Both analytical and numerical simulations predict the axially symmetric circulatory convection motion determined by the Marangoni effect at the droplet-free surface. Due to a curvature of the drop interface a temperature gradient along its free surface always exists. Thus, the thermocapillary convection within the ellipsoidal droplets in overheated FSSF is possible for the arbitrarily small Marangoni numbers. Possible experimental observations enabling the checking of our predictions are proposed.

Measurement of wave propagation through a tube using dual transducers for elastography in arteries

Objective. Measuring waves induced with acoustic radiation force (ARF) in arteries has been studied over the last decade. To date, it remains a challenge to quantitatively assess the local arterial biomechanical properties. The cylindrical shape and waveguide behavior of waves propagating in the arterial wall pose complexities to determining the mechanical properties of the artery. Approach. In this paper, an artery-mimicking tube in water is examined utilizing three-dimensional measurements. The cross-section of the tube is measured while a transducer is translated over 41 different positions along the length of the tube. Motion in the radial direction is calculated using two components of motion which are measured from the two orthogonal views of the cross-section. This enables more accurate estimation of motion along the circumference of tube. Main results. The results provide more information to categorize the motion in tube wall into two types of responses: a transient response and a steady state response. The transient response is caused by ARF application and the waves travel along the length of the tube for a relatively short period of time. This corresponds to the axial and circumferential propagating waves. The two circumferential waves travel along the circumference of tube in CW (clockwise) and CCW (counter-clockwise) direction and result in a standing wave. By using a directional filter, the two waves were successfully separated, and their propagation was more clearly visualized. As a steady state response, a circumferential mode is generated showing a symmetric motion (i.e. the proximal and distal walls move in the opposite direction) following the transient response. Significance. This study provides a more comprehensive understanding of the waves produced in an artery-mimicking tube with ARF application, which will provide opportunities for improving measurement of arterial mechanical properties.

Two distinct compartments of a ctenophore comb plate provide structural and functional integrity for the motility of giant multicilia

Comb plates are large ciliary structures uniquely seen in comb jellies (ctenophores).1,2,3 A comb plate is constructed from tens of thousands of cilia that are bundled together by structures called compartmenting lamellae (CLs).4,5,6 We previously reported the first component of the CL, CTENO64, and found that it was specifically found in ctenophores and was essential for the determination of ciliary orientation.3 However, CTENO64 is localized only in the proximal region of the CL; therefore, the molecular architecture of the CL over the entire length of a comb plate has not been elucidated. Here, we identified a second CL component, CTENO189. This ctenophore-specific protein was present in the distal region of comb plates, with a localization clearly segregated from CTENO64. Knockdown of the CTENO189 gene using morpholino antisense oligonucleotides resulted in complete loss of CLs in the distal region of comb plates but did not affect the formation of comb plates or the orientation of each cilium. However, the hexagonal distribution of cilia was disarranged, and the metachronal coordination of comb plates along a comb row was lost in the CTENO189 morphants. The morphant comb plate showed asymmetric ciliary-type movement in normal seawater, and in a high-viscosity solution, it could not maintain the normal waveforms but showed a symmetric flagellar-type movement. Our findings demonstrated two distinct compartments of a comb plate: the proximal CL as the building foundation that rigidly fixes the ciliary orientation, and the distal CL that reinforces the elastic connection among cilia to overcome the hydrodynamic drag of giant multiciliary plates.

Effects of Cha-Cha Dance Training on the Balance Ability of the Healthy Elderly.

Neuro-musculo-skeletal degradations with advancing age are generally accompanied with mobility problems and poor health status, contributing to impaired physical function and increased risk of falls. In an effort to diminish a fall-related risk such as unstable balance, a variety of interventions have been studied and implemented. Yet, there have been few studies to evaluate the effect of Cha-cha dance training on postural balance or balance performance of the elderly. The Cha-cha dance is composed of moderate rhythm and symmetrical movements and is easy to master and even easier for the elderly to begin. The purpose of this study was to intervene the fitness exercise through 12-week Cha-cha dance training, evaluate its impact on the balance ability of the elderly, and provide a scientific experimental basis for the elderly to participate in the Cha-cha dance exercise. Forty healthy elderly people with no difference in balance ability were randomly divided into two groups. The Cha-cha training group (CTG, n = 20) regularly participated in Cha-cha dance class, 3 times a week, 90 min each time, for a total of 12 weeks, and the control group (CONG, n = 20) did not participate in the class and engaged to their regular daily life. Dynamic and static balance were measured at pre and post intervention. Overall, the results showed that dynamic balance and static balance in CTG were significantly improved after the intervention. In addition, the results showed that the improvement was more significant in trials in left foot than right foot, and trials in closed eyes than open eyes, respectively. In conclusion, a 12-week Cha-cha dance class or program alone can be an effective intervention to improve balance of the elderly.

Mechanism Design and Control of a Winged Hovering Robot With Flapping Angle Constraint

Abstract In this paper, we first presented a four-bar linkage mechanism for actuating the wings in a flapping wing flying robot. After that, given the additional constraints imposed by the four-bar linkage, we parameterized the wing kinematics to provide sufficient control authority for stabilizing the system during 3D hovering. The four-bar linkage allows the motors to spin continuously in one direction while generating flapping motion on the wings. However, this mechanism constrains the flapping angle range which is a common control parameter in controlling such systems. To address this problem, we divided each wingbeat cycle into four variable-time segments which is an extension to previous work on split-cycle modulation using wing bias but allows the use of a constant flapping amplitude constraint for the wing kinematic. Finally, we developed an optimization framework to control the system for fast recovery while guaranteeing the stability. The results showed that the proposed control parameters are capable of creating symmetric and asymmetric motions between the two wings and, therefore can stabilize the hovering system with minimal actuation and flapping angle amplitude constraint.

Heat transfer enhancement in a channel flow using two wall-mounted flexible flags with a confined cylinder

A heat transfer system to improve the thermal performance of a channel flow with two symmetrically wall-mounted flexible flags is proposed by arranging a confined cylinder in an upstream region of the flags. The effects of the horizontal gap distance between the cylinder center and the wall-mounted position of the downstream flags (Gx) and the bending rigidity of the flags (γ) on the vortex dynamics are examined based on numerical simulations of the fluid-structure-thermal interaction using a penalty-immersed boundary method. Four distinct flapping modes of the two downstream flags are identified in the regime map of (Gx, γ): an out-of-phase flapping mode with symmetric motion of the flags (OS mode) and an out-of-phase flapping mode with non-symmetric motion of the flags (ON mode), and an in-phase flapping mode (I mode) and combined flapping mode in which the I mode and ON mode are presented alternately with time (ION mode). Heat transfer systems consisting of two flags under the OS and ON modes achieve improved thermal efficiency compared to that for a clean channel system (CS) due to vortex-to-vortex interactions promoting fluid mixing between the core cold fluid and near-wall hot fluid. However, the thermal efficiency for the systems in the I and ION modes decreases due to the small increase in the heat transfer rate for the I mode and a large deficit of the mechanical energy loss for the ION mode, respectively. When the values of Gx, γ and the Reynolds number are optimal, the present system in the OS mode results in an increase of the heat transfer rate by approximately 177% with an accompanying increase of the thermal efficiency up to 24% compared to that for the CS (despite an increase of the mechanical energy loss of 1021%).

Threshold of Stochastic SIRS Epidemic Model from Infectious to Susceptible Class with Saturated Incidence Rate Using Spectral Method

Stochastic SIRS models play a key role in formulating and analyzing the transmission of infectious diseases. These models reflect the environmental changes of the diseases and their biological mechanisms. Therefore, it is very important to study the uniqueness and existence of the global positive solution to investigate the asymptotic properties of the model. In this article, we investigate the dynamics of the stochastic SIRS epidemic model with a saturated incidence rate. The effects of both deterministic and stochastic distribution from infectious to susceptible are analyzed. Our findings show that the occurrence of symmetry breaking as a function of the stochastic noise has a significant advantage over the deterministic one to prevent the spread of the infectious diseases. The larger stochastic noise will guarantee the control of epidemic diseases with symmetric Brownian motion. Periodic outbreaks and re-infection may occur due to the existence of feedback memory. It is shown that the endemic equilibrium is stable under some suitable initial conditions, taking advantage of the symmetry of the large amount of contact structure. A numerical method based on Legendre polynomials that converts the given stochastic SIRS model into a nonlinear algebraic system is used for the approximate solution. Finally, some numerical experiments are performed to verify the theoretical results and clearly show the sharpness of the obtained conditions and thresholds.

Motor Control Studies on Bimanual Coordination - Does the Left Hand not Know What the Right Hand is Doing? -

운동조절학적 관점에서 양손은 협응을 통해 조화롭게 움직이므로 오른손이 하는 일을 왼손이 모르게 하는 것은 불가능하다. 양손 움직임의 리듬, 진폭(길이), 방향이 대칭이거나 동위상으로 움직일 때 안정적인 협응 패턴이 관찰되고, 한손의 움직임이 다른 손의 움직임에 영향을 미친다는 사실을 보여준다. 뇌량은 대뇌 좌우 반구의 정보를 교환하는 역할로 양손 협응에 기여한다. 하지만, 협응 능력은 특정 부위의 기능에 의존적이지 않고, 상황에 따라 다양한 신경 조합들의 상호작용으로 유도된다. 인간의 협응 능력을 고려할 때, “오른손이 하는 일을 왼손이 모르게 하라”는 예수의 말씀은 ‘자신도 모르게 하라’는 새롭게 해석된다.It is impossible to keep the left hand from knowing what the right hand is doing in a motor control perspective. Bimanual movements are closely linked through coordination to perform harmonious movements. The optimal coordination pattern can be observed when the rhythm, amplitude (length), direction are constrained in the bimanual movements. Symmetrical or in-phase movements between the limbs demonstrate the basic human coordination pattern, which is characterized by stable movements. When performing a bimanual task, the movement of one hand affects the movement of the other hand because information about left and right movement is exchanged via the corpus callosum. Given the functions and roles of the brain, it appears that coordination is not dependent on a single locus of the brain, but rather appears as a result of the interaction of different neural combinations depending on the situation. Although the mechanism underlying bimanual coordination has yet to be fully understood, it is clear that the left and right hands are inextricably linked and influence each other's movements. Thus, ‘don't let the left hand know what the right hand is doing’ means a lack of self-consciousness of one’s deeds.

Reduction in manual asymmetry and decline in fine manual dexterity in right-handed older adults with mild cognitive impairment

ABSTRACT Research in Parkinson’s or Alzheimer’s disease suggests that hand function is affected by neurodegenerative diseases. However, little is known about the relationship between hand function and mild cognitive impairment (MCI). Therefore, we conducted a kinematic analysis of unimanual hand movements in MCI patients to answer whether manual asymmetries and manual dexterity are affected or preserved in this condition. Forty-one MCI patients and fifty healthy controls were tested with the Purdue Pegboard test. All participants were right-handed. Kinematic analyses (by hand) were calculated for path length, angle, and linear and angular velocities during reaching, grasping, transport and inserting. Group differences were tested by with factorial MANOVAs and laterality indexes (LI) were assessed. Groups were compared on “Right–Left” hand correlations to identify kinematics that best single-out patients. Kinematics from grasping and inserting were significantly more deteriorated in the MCI group, while outcomes for reaching and transport denoted superior performance. LIs data showed symmetry of movements in the MCI group, during reaching and transport. Comparisons of “Right–Left” hand correlations revealed that kinematics in reaching and transport were more symmetrical in patients. This study showed a deterioration of fine manual dexterity, an enhancement in gross dexterity of upper-limbs, and symmetrical movements in MCI patients.

Approaching to the stable transportation based on motion profile phases for material handling system

Transportation is a critical part of logistics in any economy. In the context of industrialization and modernization, a solution to enable utilization of autonomous vehicles that work with uncertain factors, high speed, and continuous motion is urgent. The anti-vibration control of this system plays a vital role in avoiding accidents, especially when sharing space with humans. Therefore, in this paper, non-vibration control strategies, such as the linear motion profile (LMP), symmetric motion curve (SMC), and asymmetric motion curve (ASMC), based on the phases of motion profiles, are investigated for a lifting type of carrier. Firstly, the system modelling of both the vehicle and cargo is conducted. Secondly, by analysing the dynamic characteristics, the motion performance in both the acceleration phase and deceleration phase is achieved. Several constraints are validated in order to maintain the stable motion. In the experiments, four cases including a test without the algorithm and with the algorithm with LMP, SMC, and ASMC are examined. From these results, the peak acceleration of these schemes, LMP, SMC, and ASMC, respectively, decrease by 28.5%, 20.3%, and 10.1% compared with the case without the algorithm. The contributions of this research are (i) to analyse the poles and zeros for a load–vehicle system with respect to its dynamic characteristics, (ii) to propose a vibration attenuation control scheme based on the classification of the motion phases, and (iii) to employ various smoothing profiles to demonstrate the comparative performance. These results can be widely applied to the sustainability of not only the logistics field but also digital trade.

A fascia bow traction method for the treatment of unilateral marginal mandibular nerve paralysis after mandibulectomy for head and neck cancer

BackgroundUnilateral paralysis of the marginal mandibular nerve (UPMMN) after head and neck cancer surgery is a relatively common condition that causes deformity and an asymmetric appearance of the lower lip and impairs the quality of life of patients. We developed a novel fascia grafting method to improve the appearance of the lower lip in patients with UPMMN. MethodsTwo fascia strips and a small fascia loop connecting the two strips are used: one is fixed horizontally to pull the lower lip toward the paralyzed side, and the other is fixed in a bow shape at rest to avoid approaching the lateral mandibular margin. When patients smile or open their mouths, the bow-shaped graft straightens, pulling the paralyzed lower lip laterally downward through the small connecting loop. We used this method to treat four patients with UPMMN who had undergone head and neck cancer ablation. The symmetry and movement of the lower lip were assessed using preoperative and postoperative photographs of three poses (at rest, smiling, and opening the mouth). ResultsThe fascia grafting procedure restored the symmetry of the lower lip at rest and greatly improved symmetrical lower lip movement when smiling and opening the mouth. According to photographic evaluation scores, all patients had poor lower lip symmetry in the three poses before the procedure, whereas after the procedure, three had excellent lower lip symmetry, and one had good lower lip symmetry. There was a significant difference between the scores before and after the surgery. ConclusionsFascia grafting is easy and minimally invasive, allows patients to generate an almost symmetrical smile, and consequently improves their QOL. This method may be particularly useful when the lateral mandibular bone is resected during cancer surgery, and the defect is reconstructed with metal plates/soft tissue, as the method does not require approaching the lateral mandibular region.

Biomechanical Analysis of Stoop and Free-Style Squat Lifting and Lowering with a Generic Back-Support Exoskeleton Model.

Musculoskeletal disorders (MSDs) induced by industrial manual handling tasks are a major issue for workers and companies. As flexible ergonomic solutions, occupational exoskeletons can decrease critically high body stress in situations of awkward postures and motions. Biomechanical models with detailed anthropometrics and motions help us to acquire a comprehension of person- and application-specifics by considering the intended and unintended effects, which is crucial for effective implementation. In the present model-based analysis, a generic back-support exoskeleton model was introduced and applied to the motion data of one male subject performing symmetric and asymmetric dynamic manual handling tasks. Different support modes were implemented with this model, including support profiles typical of passive and active systems and an unconstrained optimal support mode used for reference to compare and quantify their biomechanical effects. The conducted simulations indicate that there is a high potential to decrease the peak compression forces in L4/L5 during the investigated heavy loaded tasks for all motion sequences and exoskeleton support modes (mean reduction of 13.3% without the optimal support mode). In particular, asymmetric motions (mean reduction of 14.7%) can be relieved more than symmetric ones (mean reduction of 11.9%) by the exoskeleton support modes without the optimal assistance. The analysis of metabolic energy consumption indicates a high dependency on lifting techniques for the effectiveness of the exoskeleton support. While the exoskeleton support substantially reduces the metabolic cost for the free-squat motions, a slightly higher energy consumption was found for the symmetric stoop motion technique with the active and optimal support mode.

Effectiveness of a Laparoscopic Training Model for Pediatric Surgeons During COVID-19 Pandemic: A Single-Center Experience.

Background: During COVID-19 pandemic, many restrictions were applied in the field of health care. For this reason, we decided to adopt the laparoscopic simulator Laparo® Analytic to allow the trainees of our pediatric surgery training program to continue their training activity, and we determined its impact on their surgical education. Methods: We used Laparo Analytic Simulator for laparoscopic surgery training among the residents of our center. Fifteen residents from different years of the pediatric surgery program participated in this study. Each participant performed a 2-hour training session per week, consisting of three different exercises: Rubber Bands, Knotting, and Suturing. For each training session, the following parameters were analyzed: training time, economy of movement, smoothness, instrument activity (IA), instrument visibility (IV), and instrument symmetry. Results: Results were collected after the first training session (T0), at 3 months after the beginning of the study (T1) and at 6 months after the beginning of the study (T2). At T2 of training with Laparo Analytic Simulator, residents were able to complete their tasks significantly faster (P = .001) and had a significant improvement in smoothness of movements, IA, IV, and instrument symmetric movements during the tasks analyzed. Conclusion: On the basis of our results, we believe that Laparo analytic is an excellent system to adopt in minimally invasive surgery (MIS) training programs, in particular, during periods of surgical restrictions, as COVID-19 pandemic, or in centers with a limited MIS activity.