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In order to meet the increasing demand of high-performance control in industrial production, a new sliding mode variable structure control algorithm, Asymptotic Sliding Mode Control (ASMC), is designed in this study to solve the serious chattering problem of sliding mode control. Firstly, a traditional sliding mode exponential approximation law control model and a state space and control function are constructed based on sliding mode control. Secondly, by eliminating the jitter factor, ASMC algorithm is combined with sliding mode control to achieve precise control of permanent magnet synchronous motor (PMSM) and improve its performance. The experimental results indicated that in the simulation experiment, the research system tended to stabilize within 0.2-0.3 seconds, and the system chattering was significantly suppressed. And its output was smoother, the jitter amplitude was significantly reduced by 1/3, and the output torque was more stable. In addition, when the parameter H0 changed to 2H0, the overall speed curve did not change much, with only a slight overshoot. The overshoot was only 2.8%, and the change amplitude was maintained at around 25r/min, indicating that the research system had strong self stability performance. In actual experiments, the current command oscillation of the research system was significantly reduced. The local graph showed that the output fluctuation amplitude of the asymptotic approach law actual control was significantly smaller under no-load disturbance. When the H0 changed towards 2H0, the actual adjustment time was about 0.1 seconds, which was consistent with the simulation experiment. Therefore, the contribution of the research is that the ASMC algorithm can suppress the chattering problem of the system and improve the approaching speed, thus improving the speed regulation quality of the system. This new algorithm has great theoretical and practical significance for improving the performance of PMSM, and is practical in the actual vector control system of PMSM.

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The loss of a hand disrupts the sophisticated neural pathways between the brain and the hand, severely affecting the level of independence of the patient and the ability to carry out daily work and social activities. Recent years have witnessed a rapid evolution of surgical techniques and technologies aimed at restoring dexterous motor functions akin to those of the human hand through bionic solutions, mainly relying on probing of electrical signals from the residual nerves and muscles. Here, we report the clinical implementation of an interface aimed at achieving this goal by exploiting muscle deformation, sensed through passive magnetic implants: the myokinetic interface. One participant with a transradial amputation received an implantation of six permanent magnets in three muscles of the residual limb. A truly self-contained myokinetic prosthetic arm embedding all hardware components and the battery within the prosthetic socket was developed. By retrieving muscle deformation caused by voluntary contraction through magnet localization, we were able to control in real time a dexterous robotic hand following both a direct control strategy and a pattern recognition approach. In just 6 weeks, the participant successfully completed a series of functional tests, achieving scores similar to those achieved when using myoelectric controllers, a standard-of-care solution, with comparable physical and mental workloads. This experience raised conceptual and technical limits of the interface, which nevertheless pave the way for further investigations in a partially unexplored field. This study also demonstrates a viable possibility for intuitively interfacing humans with robotic technologies.

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The present report aims to describe the case of a duodenal obstruction ileus in a dairy cow that was caused by a cage magnet. The 4.7-year-old German Fleckvieh cow was hospitalized because of symptoms of intestinal obstruction such as anorexia, noticeable drop in milk yield, reduced defecation, dehydration and positive percussion and swinging auscultation in a circumscribed area cranial of the right flank over the last 2 ribs. Six months as well as 3 days prior to hospitalization the cow had already been treated for signs of hardware disease, which included administration of a cage magnet.After the initial clinical diagnostic procedure on hospital admission, a diagnostic laparotomy in the right paralumbar fossa was performed to identify the cause of the ileus. The cranial part of the duodenum was markedly dilated, and a solid foreign body was found obstructing the intestine immediately aboral to the duodenal sigmoid flexure. This was identified as a cage magnet, which was massaged in retrograde direction into the pyloric antrum and removed via abomasotomy. The cow recovered from surgical intervention and was discharged from the hospital 6 days later.The present report describes an unusual complication of cage magnet administration, which is a standard veterinary procedure and generally considered a safe treatment option in cows with clinical signs of acute traumatic reticuloperitonitis.

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Room-temperature ferromagnets are high-value targets for discovery given the ease by which they could be embedded within magnetic devices. However, the multitude of potential interactions among magnetic ions and their surrounding environments renders the prediction of thermally stable magnetic properties challenging. Therefore, it is vital to explore methods that can effectively screen potential candidates to expedite the discovery of novel ferromagnetic materials within highly intricate feature spaces. To this end, we explore machine-learning (ML) methods as a means to predict the Curie temperature (Tc) of ferromagnetic materials by discerning patterns within materials databases. This study emphasizes the importance of feature analysis and selection in ML modeling and demonstrates the efficacy of our gradient-boosted statistical feature-selection workflow for training predictive models. The models are fine-tuned through Bayesian optimization, using features derived solely from the chemical compositions of the materials data, before the model predictions are evaluated against literature values. We have collated ca. 35,000 Tc values and the performance of our workflow is benchmarked against state-of-the-art algorithms, the results of which demonstrate that our methodology is superior to the majority of alternative methods. In a 10-fold cross-validation, our regression model realized an R2 of (0.92 ± 0.01), an MAE of (40.8 ± 1.9) K, and an RMSE of (80.0 ± 5.0) K. We demonstrate the utility of our ML model through case studies that forecast Tc values for rare-earth intermetallic compounds and generate magnetic phase diagrams for various chemical systems. These case studies highlight the importance of a systematic approach to feature analysis and selection in enhancing both the predictive capability and interpretability of ML models, while being devoid of potential human bias. They demonstrate the advantages of such an approach over a mere reliance on algorithmic complexity and a black-box treatment in ML-based modeling within the domain of computational materials science.

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BACKGROUND: The partial diversion of intestinal contents facilitates achieving and maintaining weight loss and improving glycemic control in patients with obesity and with or without T2DM. The purpose of this study is to report our experience and 1-year follow-up with novel modification of SADI-S. METHODS: This study is a part of a multicentric trial of patients that underwent primary side-to-side duodeno-ileostomy and sleeve gastrectomy (SG) with GT metabolic solutions magnetic anastomosis system. Feasibility, safety, and initial efficacy were evaluated. RESULTS: The mean age of the patients included was 48 ± 8.75 years and the preoperative BMI was 43.32 ± 2.82 kg/m2. The complications were present in 30% of patients. The anastomosis patency was confirmed by the passage of radiological contrast under fluoroscopy at a mean of 17 days (17-29 days), and the mean expulsion time was 42 days (32-62). The mean diameter of the anastomosis after the magnet expulsion was 13.8 × 11.4 mm. The percentage of total weight lost at 1 year was 38.68 ± 8.48% (p < 0.001). The percentage of excess weight loss 82.5 ± 18.44% (p < 0.001) and improvements in glucose profiles were observed. Mean baseline HbA1c 5.77 ± 0.31% was reduced to 5.31 ± 0.26% (p < 0.024). CONCLUSIONS: Latero-lateral duodeno-ileostomy + SG with magnetic duodenal bipartition is afeasible and reasonably safe technique and induces weight loss in patients with obesity and improvement of glycemic control. This modification could be considered as an option to standard SADI-S or as a first step in two stages procedure. However, larger studies are needed. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: #NCT05322122.

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In cochlear implant recipients, the diagnostic value of magnetic resonance imaging (MRI) scans is reduced by image artifacts. The static magnetic field of a 3.0T scanner is associated with the risk of implant demagnetization. The development of rotatable implant magnets aimed to support the advancement of 3.0T MRI scanners and eliminate the risk of demagnetization of cochlear implant magnets. This study aimed to compare the image artifacts caused by first-t and second-generation rotatable cochlear implant magnets in 3.0T MRI. Three Tesla MRI T2W TSE sequences were performed on 3 subjects with first- and second-generation rotatable cochlear implant magnets. The cochlear implant was fixed to the head at the implantation position by a swim cap. The size of the image artifact was determined in the transverse plane. Intraindividual comparative analyses showed that within the margin of combined uncertainty of 5 mm at a resolution of 2 mm, the cochlear implant-induced image artifacts in all subjects showed for both (first- and second-generation rotatable cochlear implant magnets), the same maximum image artifact dimension of 125 mm. We could show that no difference in image artifact size was detected within the margin of error determined by resolution, localized induced shift of the scan, and reproducibility of the tilt angle of the head relative to the chest in a living subject. Assumed improved magnet attachment can be reached without compromising of the magnet artifact size.

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The "5 gauss line" is a phrase that is likely to be familiar to everyone working with MRI, but what is its significance, how was it defined, and what changes are currently in progress? This review explores the history of 5 gauss (0.5 mT) as a threshold for protecting against inadvertently putting cardiac pacemakers, implantable cardioverter defibrillators, and other active implantable medical devices into a "magnet mode." Additionally, it describes the background to the recent change of this threshold to 9 gauss (0.9 mT) in the International Standard IEC 60601-2-33 edition 4.0 that defines basic safety requirements for MRI. Practical implications of this change and some ongoing and emerging issues are also discussed.

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INTRODUCTION: Management of gastroesophageal reflux disease after bariatric procedures can be challenging. There are very few long-term studies in this arena. This study aims to evaluate the long-term outcomes of the magnetic sphincter augmentation (MSA) reflux management system in a cohort of bariatric patients who had previously undergone sleeve gastrectomy and Roux-en-Y gastric bypass, with a focus on assessing gastroesophageal reflux disease (GERD) scores, medication use, and patient-reported symptoms. METHODS: We conducted a retrospective chart review of 16 consecutive bariatric patients who received MSA implants following sleeve gastrectomy (n = 14) or gastric bypass (n = 2) surgeries. Data were collected regarding BMI, GERD quality of life assessments (GERD-HRQL), reflux symptoms, and use of PPIs in the sleeve/RGB patients through an extended period with a mean follow-up of 48 months. RESULTS: Patients were followed up for a range of .5-84 months. Preoperative assessments included upper gastrointestinal imaging (UGI), high-resolution manometry, Bravo pH studies, and esophagogastroduodenoscopy (EGD). Three patients exhibited reflux on UGI, and 13/13 patients had positive Bravo studies preoperatively. Sixteen patients had a lower esophageal sphincter (LES) pressure under 18 mmHg, and eight patients had biopsy-proven esophagitis. Long-term outcomes are as follows. Daily PPI use fell from 88 to 25% at greater than three years. GERD-HRQL scores fell from 50.6 at baseline (range 27-70) and normalized at long-term follow-up. GERD symptom of regurgitation completely resolved. At long term, two patients had dysphagia and two patients had ongoing reflux. No adverse events were noted. CONCLUSION: This is the first long-term outcomes study of magnetic sphincter augmentation placement after bariatric surgery. Our study showed the majority of patients had long-term improvement in GERD-HRQL scores and resolution/ relief of their reflux symptoms, with decreased use of PPIs. MSA is a safe, effective and durable management tool for reflux after bariatric surgery in carefully selected patients.

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Magnetic nanoparticles have emerged as a promising approach to improving cancer treatment. However, many nanoparticle designs fail in clinical trials due to a lack of understanding of how to overcome the in vivo transport barriers. To address this shortcoming, we develop a computational model aimed at the study of magnetic nanoparticles in vitro and in vivo. In this paper, we present an important building block for this overall goal, namely an efficient computational model of the in-flow capture of magnetic nanoparticles by a cylindrical permanent magnet in an idealized test setup. We use a continuum approach based on the Smoluchowski advection-diffusion equation, combined with a simple approach to consider the capture at an impenetrable boundary, and derive an analytical expression for the magnetic force of a cylindrical magnet of finite length on the nanoparticles. This provides a simple and numerically efficient way to study different magnet configurations and their influence on the nanoparticle distribution in three dimensions. Such an in silico model can increase insight into the underlying physics, help to design prototypes, and serve as a precursor to more complex systems in vivo and in silico.

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Purpose: To assess the effectiveness and pain intensity associated with magnetic ureteral stent removal using a retriever, without the aid of ultrasound guidance. Methods: We prospectively enrolled 100 patients who underwent retrograde rigid and flexible ureterorenoscopy with or without laser lithotripsy for ureteronephrolithiasis treatment from September 2021 to June 2023. These patients were assigned in two groups. Group 1 underwent the traditional ureteral stent insertion, while Group 2 underwent magnetic ureteral stent insertion. Both insertion and removal times were documented. The indwelling time for ureteral stents was 14 days. One group underwent stent removal via flexible cystoscopy using grasping forceps and the other group using just a magnetic retriever, without the aid of ultrasound guidance. The numeric pain rating scale, recommendation rate, and a standardized self-answered ureter stent symptoms questionnaire (USSQ) were obtained directly after stent removal. Results: Both groups presented comparable characteristics in factors such as age, body mass index, history of stone treatments, procedure type, and complication rates during and post-surgery. Time taken for ureteral stent insertion did not differ significantly between the groups (131.2 seconds for Group 1 vs 159.1 seconds for Group 2). However, the stent removal time (152.1 seconds for Group 1 vs 35.4 seconds for Group 2) and pain intensity (6 for Group 1 vs 2 for Group 2) were significantly lower for Group 2. Furthermore, five out of the six sections of the USSQ showed significantly better results for Group 2. Conclusions: The use of magnetic ureteral stents, as a safe and efficient alternative to conventional ureteral stents, not only eliminates the need for cystoscopy but also conserves resources and reduces patient discomfort.

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BACKGROUND: Single-anastomosis metabolic/bariatric surgery procedures may lessen the incidence of anastomotic complications. This study aimed to evaluate the feasibility and safety of performing side-to-side duodenoileal (DI) bipartition using magnetic compression anastomosis (MCA). In addition, preliminary efficacy, quality of life (QoL), and distribution of food through the DI bipartition were evaluated. METHODS: Patients with a body mass index (BMI) of ≥35.0 to 50.0 kg/m2 underwent side-to-side DI bipartition with the magnet anastomosis system (MS) with sleeve gastrectomy (SG). By endoscopic positioning, a distal magnet (250 cm proximal to the ileocecal valve) and a proximal magnet (first part of the duodenum) were aligned with laparoscopic assistance to inaugurate MCA. An isotopic study assessed transit through the bipartition. RESULTS: Between March 14, 2022 to June 1, 2022, 10 patients (BMI of 44.2 ± 1.3 kg/m2) underwent side-to-side MS DI. In 9 of 10 patients, an SG was performed concurrently. The median operative time was 161.0 minutes (IQR, 108.0-236.0), and the median hospital stay was 3 days (IQR, 2-40). Paired magnets were expelled at a median of 43 days (IQR, 21-87). There was no device-related serious advanced event within 1 year. All anastomoses were patent with satisfactory diameters after magnet expulsion and at 1 year. Respective BMI, BMI reduction, and total weight loss were 28.9 ± 1.8 kg/m2, 15.2 ± 1.8 kg/m2, and 34.2% ± 4.1%, respectively. Of note, 70.0% of patients reported that they were very satisfied. The isotopic study found a median of 19.0% of the meal transited through the ileal loop. CONCLUSION: Side-to-side MCA DI bipartition with SG in adults with class II to III obesity was feasible, safe, and efficient with good QoL at 1-year follow-up. Moreover, 19% of ingested food passed directly into the ileum.

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BACKGROUND: The magnetic compression technique has been used to establish an animal model of tracheoesophageal fistula (TEF), but the commonly shaped magnets present limitations of poor homogeneity of TEF and poor model control. We designed a T-shaped magnet system to overcome these problems and verified its effectiveness via animal experiments. AIM: To investigate the effectiveness of a T-shaped magnet system for establishing a TEF model in beagle dogs. METHODS: Twelve beagles were randomly assigned to groups in which magnets of the T-shaped scheme (study group, n = 6) or normal magnets (control group, n = 6) were implanted into the trachea and esophagus separately under gastroscopy. Operation time, operation success rate, and accidental injury were recorded. After operation, the presence and timing of cough and the time of magnet shedding were observed. Dogs in the control group were euthanized after X-ray and gastroscopy to confirm establishment of TEFs after coughing, and gross specimens of TEFs were obtained. Dogs in the study group were euthanized after X-ray and gastroscopy 2 wk after surgery, and gross specimens were obtained. Fistula size was measured in all animals, and then harvested fistula specimens were examined by hematoxylin and eosin (HE) and Masson trichrome staining. RESULTS: The operation success rate was 100% for both groups. Operation time did not differ between the study group (5.25 min ± 1.29 min) and the control group (4.75 min ± 1.70 min; P = 0.331). No bleeding, perforation, or unplanned magnet attraction occurred in any animal during the operation. In the early postoperative period, all dogs ate freely and were generally in good condition. Dogs in the control group had severe cough after drinking water at 6-9 d after surgery. X-ray indicated that the magnets had entered the stomach, and gastroscopy showed TEF formation. Gross specimens of TEFs from the control group showed the formation of fistulas with a diameter of 4.94 mm ± 1.29 mm (range, 3.52-6.56 mm). HE and Masson trichrome staining showed scar tissue formation and hierarchical structural disorder at the fistulas. Dogs in the study group did not exhibit obvious coughing after surgery. X-ray examination 2 wk after surgery indicated fixed magnet positioning, and gastroscopy showed no change in magnet positioning. The magnets were removed using a snare under endoscopy, and TEF was observed. Gross specimens showed well-formed fistulas with a diameter of 6.11 mm ± 0.16 mm (range, 5.92-6.36 mm), which exceeded that in the control group (P < 0.001). Scar formation was observed on the internal surface of fistulas by HE and Masson trichrome staining, and the structure was more regular than that in the control group. CONCLUSION: Use of the modified T-shaped magnet scheme is safe and feasible for establishing TEF and can achieve a more stable and uniform fistula size compared with ordinary magnets. Most importantly, this model offers better controllability, which improves the flexibility of follow-up studies.

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Although the application of magnetic compression anastomosis is becoming increasingly widespread, the magnets used in earlier studies were mostly in the shape of a whole ring. Hence, a deformable self-assembled magnetic anastomosis ring (DSAMAR) was designed in this study for gastrointestinal anastomosis. Furthermore, its feasibility was studied using a beagle model. The designed DSAMAR comprised 10 trapezoidal magnetic units. Twelve beagles were used as animal models, and DSAMARs were inserted into the stomach and colon through the mouth and anus, respectively, via endoscopy to achieve gastrocolic magnamosis. Surgical time, number of failed deformations, survival rate of the animals, and the time of magnet discharge were documented. A month later, specimens of the anastomosis were obtained and observed with the naked eye as well as microscopically. In the gastrocolic anastomosis of the 12 beagles, the procedure took 65-120 min. Although a deformation failure occurred during the operation in one of the beagles, it was successful after repositioning. The anastomosis was formed after the magnet fell off 12-18 days after the operation. Naked eye and microscopic observations revealed that the anastomotic specimens obtained 1 month later were well-formed, smooth, and flat. DSAMAR is thus feasible for gastrointestinal anastomosis under full endoscopy via the natural orifice.

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Purpose: Currently, no solution exists to restore natural eyelid kinematics for patients with complete eyelid paralysis due to loss of function of both the levator palpebrae superioris and orbicularis oculi. These rare cases are prone to complications of chronic exposure keratopathy which may lead to corneal blindness. We hypothesized that magnetic force could be used to fully automate eyelid movement in these cases through the use of eyelid-attached magnets and a spectacle-mounted magnet driven by a programmable motor (motorized magnetic levator prosthesis [MMLP]). Methods: To test this hypothesis and establish proof of concept, we performed a finite element analysis (FEA) for a prototype MMLP to check the eyelid-opening force generated by the device and verified the results with experimental measurements in a volunteer with total bidirectional eyelid paralysis. The subject was then fitted with a prototype to check the performance of the device and its success. Results: With MMLP, eye opening was restored to near normal, and blinking was fully automated in close synchrony with the motor-driven polarity reversal, with full closure on the blink. The device was well tolerated, and the participant was pleased with the comfort and performance. Conclusions: FEA simulation results conformed to the experimentally observed trend, further supporting the proof of concept and design parameters. This is the first viable approach in human patients with proof of concept for complete reanimation of a bidirectionally paretic eyelid. Further study is warranted to refine the prototype and determine the feasibility and safety of prolonged use. Translational Relevance: This is first proof of concept for our device for total bidirectional eyelid paralysis.

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Magnet ingestion in children can lead to serious complications, both acutely and chronically. This case report discusses the treatment approach for a case involving multiple magnet ingestions, which resulted in a jejuno-colonic fistula, segmental intestinal volvulus, hepa-tosteatosis, and renal calculus detected at a late stage. Additionally, we conducted a literature review to explore the characteristics of intestinal fistulas caused by magnet ingestion. A six-year-old girl was admitted to the Pediatric Gastroenterology Department pre-senting with intermittent abdominal pain, vomiting, and diarrhea persisting for two years. Initial differential diagnoses included celiac disease, cystic fibrosis, inflammatory bowel disease, and tuberculosis, yet the etiology remained elusive. The Pediatric Surgery team was consulted after a jejuno-colonic fistula was suspected based on magnetic resonance imaging findings. The physical examination revealed no signs of acute abdomen but showed mild abdominal distension. Subsequent upper gastrointestinal series and contrast enema graphy confirmed a jejuno-colonic fistula and segmental volvulus. The family later reported that the child had swallowed a magnet two years prior, and medical follow-up had stopped after the spontaneous expulsion of the magnets within one to two weeks. Surgical intervention was necessary to correct the volvulus and repair the large jejuno-colonic fistula. To identify relevant studies, we conducted a detailed literature search on magnet ingestion and gastrointestinal fistulas according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. We identified 44 articles encompassing 55 cases where symptoms did not manifest in the acute phase and acute abdomen was not observed. In 29 cases, the time of magnet ingestion was unknown. Among the 26 cases with a known ingestion time, the average duration until fistula detection was 22.8 days (range: 1-90 days). Fistula repairs were performed via laparotomy in 47 cases.

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OBJECTIVE: Describe presenting signs, diagnostic findings, and magnet-assisted endoscopic removal method of ferromagnetic gastric foreign bodies (FBs) in dogs. CLINICAL PRESENTATION: Four dogs presented with ingestion of sharp metallic FBs. The presence of gastric FBs was confirmed by abdominal radiography. RESULTS: In 3 cases, initial attempts at endoscopic removal were unsuccessful because of ingesta and fluid in the stomach. A magnet contained within a Roth net was introduced endoscopically. Magnet and attached objects were successfully removed from the stomach. In the fourth case, removal with a magnet was judged to be the most expedient method of removal because multiple metallic objects were present. CLINICAL RELEVANCE: An endoscopic technique was used for the removal of difficult-to-visualize or multiple metallic FBs. The use of this technique allows the removal of ferromagnetic gastric FBs without surgery or risk of complications associated with the passage of sharp material through the gastrointestinal (GI) tract.

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BACKGROUND: Magnetic sphincter augmentation (MSA) explantation is an uncommon occurrence, and there are limited studies characterizing factors predictive of MSA explantation. This study aimed to create a nomogram to aid in determining the probability of explantation in patients before MSA implantation. METHODS: An institutional review board-approved, prospectively maintained database was retrospectively reviewed for all patients undergoing antireflux surgery between February 2015 and May 2023. All patients who underwent MSA-related procedures were included. Patients were divided into 2 groups, explant group and nonexplant group, and differences were analyzed. A multivariable logistic regression model was fitted to identify independent risk factors for predicting MSA explantation, and a nomogram-based scoring tool was developed. RESULTS: There were 227 patients (134 females and 93 males) with a mean age of 51.4 years. The explant group included 28 patients (12.3%), whereas the nonexplant group included 199 patients (87.7%). Patient sociodemographic characteristics, medical comorbidities, preoperative testing results, and surgical history were included in the analysis. The multivariable regression model resulted in 4 significant variables that were included in the nomogram. These included preoperative DeMeester score, preoperative gastroesophageal reflux disease health-related quality of life score, preoperative distal contractile integral value on manometry, and body mass index. Based on these variables, a scoring nomogram was developed with values ranging from 0 to 18. CONCLUSION: Our data were used to develop a scoring calculator capable of predicting the probability of MSA explantation. This scoring tool can guide preoperative patient selection and treatment decisions.

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