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Keywords = rib movement

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16 pages, 5818 KiB  
Case Report
Novel Sonoguided Digital Palpation and Ultrasound-Guided Hydrodissection of the Long Thoracic Nerve for Managing Serratus Anterior Muscle Pain Syndrome: A Case Report with Technical Details
by Nunung Nugroho, King Hei Stanley Lam, Theodore Tandiono, Teinny Suryadi, Anwar Suhaimi, Wahida Ratnawati, Daniel Chiung-Jui Su, Yonghyun Yoon and Kenneth Dean Reeves
Diagnostics 2025, 15(15), 1891; https://doi.org/10.3390/diagnostics15151891 - 28 Jul 2025
Viewed by 847
Abstract
Background and Clinical Significance: Serratus Anterior Muscle Pain Syndrome (SAMPS) is an underdiagnosed cause of anterior chest wall pain, often attributed to myofascial trigger points of the serratus anterior muscle (SAM) or dysfunction of the Long Thoracic Nerve (LTN), leading to significant disability [...] Read more.
Background and Clinical Significance: Serratus Anterior Muscle Pain Syndrome (SAMPS) is an underdiagnosed cause of anterior chest wall pain, often attributed to myofascial trigger points of the serratus anterior muscle (SAM) or dysfunction of the Long Thoracic Nerve (LTN), leading to significant disability and affecting ipsilateral upper limb movement and quality of life. Current diagnosis relies on exclusion and physical examination, with limited treatment options beyond conservative approaches. This case report presents a novel approach to chronic SAMPS, successfully diagnosed using Sonoguided Digital Palpation (SDP) and treated with ultrasound-guided hydrodissection of the LTN using 5% dextrose in water (D5W) without local anesthetic (LA), in a patient where conventional treatments had failed. Case Presentation: A 72-year-old male presented with a three-year history of persistent left chest pain radiating to the upper back, exacerbated by activity and mimicking cardiac pain. His medical history included two percutaneous coronary interventions. Physical examination revealed tenderness along the anterior axillary line and a positive hyperirritable spot at the mid axillary line at the 5th rib level. SDP was used to visualize the serratus anterior fascia (SAF) and LTN, and to reproduce the patient’s concordant pain by palpating the LTN. Ultrasound-guided hydrodissection of the LTN was then performed using 20–30cc of D5W without LA to separate the nerve from the surrounding tissues, employing a “fascial unzipping” technique. The patient reported immediate pain relief post-procedure, with the pain reducing from 9/10 to 1/10 on the Numeric Rating Scale (NRS), and sustained relief and functional improvement at the 12-month follow-up. Conclusions: Sonoguided Digital Palpation (SDP) of the LTN can serve as a valuable diagnostic adjunct for visualizing and diagnosing SAMPS. Ultrasound-guided hydrodissection of the LTN with D5W without LA may provide a promising and safe treatment option for patients with chronic SAMPS refractory to conservative management, resulting in rapid and sustained pain relief. Further research, including controlled trials, is warranted to evaluate the long-term efficacy and generalizability of these findings and to compare D5W to other injectates. Full article
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12 pages, 752 KiB  
Case Report
Pain and Disability Reduction Following Rib Manipulation in a Patient Recovering from Osteomyelitis of the Thoracic Spine
by Joshua Prall, James Dunning, Ian Young, Michael Ross, James Escaloni and Paul Bliton
Healthcare 2025, 13(12), 1355; https://doi.org/10.3390/healthcare13121355 - 6 Jun 2025
Viewed by 629
Abstract
Introduction: Spinal thrust manipulation has been found useful for improving pain and mobility in musculoskeletal conditions of the thoracic spine. This case report highlights the importance of incorporating high-velocity low-amplitude (HVLA) thrust manipulation to the mid-thoracic rib articulations in a patient experiencing thoracic [...] Read more.
Introduction: Spinal thrust manipulation has been found useful for improving pain and mobility in musculoskeletal conditions of the thoracic spine. This case report highlights the importance of incorporating high-velocity low-amplitude (HVLA) thrust manipulation to the mid-thoracic rib articulations in a patient experiencing thoracic spine pain associated with an acute onset of osteomyelitis at levels T7–T9. Detailed Case Description: A 49-year-old female who was recovering from osteomyelitis of the thoracic spine 4 months prior was referred to physical therapy by her neurosurgeon. Her osteomyelitis infection resulted in a bone-on-bone interaction between T7 and T9, resulting in significant thoracic spine pain. Severe restrictions in active range of motion (AROM) were found in extension and right and left rotation. At initial evaluation, the patient’s pain intensity score was 8/10 (NPRS, 0–10), the disability score was 46/50 (NDI, 0–50), and the patient-specific functional scale score was 3/10 (PSFS, 0–10). Initially, interventions included grades I-IV posterior to anterior (PA) mobilizations of the thoracic spine from levels T2 to T9, mobilization with movement of the thoracic spine for extension and rotation bilaterally, scapular stabilization, and thoracic mobility exercises. Treatment progressed to HVLA thrust manipulation techniques targeting the costotransverse articulations of ribs 2–9. Discussion: Following the initial eight treatment sessions over 4 weeks, minimal improvement was observed for pain (NPRS from 8/10 to 6/10), disability (NDI from 46/50 to 34/50), and thoracic extension AROM (13°). However, during visits 9–16, the addition of HVLA thrust manipulation targeting the costotransverse articulations resulted in significant improvements in pain, disability, and AROM. The patient was subsequently discharged after 16 visits and able to return to a full workday as a teacher without any thoracic pain or ROM restrictions. At the 6-month follow-up, the patient outcomes remained, and she was working with no restrictions. Conclusion: The addition of HVLA thrust manipulation targeting the mid-thoracic rib articulations to a program of non-thrust mobilization and exercise appeared useful for improving pain, disability, and range of motion in a patient recovering from osteomyelitis of the thoracic spine. Full article
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13 pages, 4557 KiB  
Article
Study on the Ground Pressure Manifestation Patterns of Roof Cutting and Pressure Relief
by Runhu Zheng, Bingyuan Hao, Chaoyao Shi and Tongxi Li
Appl. Sci. 2025, 15(11), 6049; https://doi.org/10.3390/app15116049 - 28 May 2025
Cited by 1 | Viewed by 306
Abstract
Pillarless mining technology is of great significance for improving coal recovery rates, but the intense mining-induced stress disturbances on gob-side entries often lead to surrounding rock instability. In this study, we focused on the ground control challenges in the headgate of Panel 81308 [...] Read more.
Pillarless mining technology is of great significance for improving coal recovery rates, but the intense mining-induced stress disturbances on gob-side entries often lead to surrounding rock instability. In this study, we focused on the ground control challenges in the headgate of Panel 81308 at Huayang Mine No. 2. Comprehensive monitoring of roof–floor convergence, rib deformation, and support resistance revealed the gob-side entry retaining deformation mechanisms with roof-cutting pressure relief; the results show that this retaining deformation exhibits the following three phases of characteristics: the rapid, decelerated, and stable stages. The average roof–floor convergence (607 mm) was significantly greater than the average rib deformation (170 mm), with floor heave accounting for 72.6% of total convergence. The coal pillar side showed dominant deformation in rib movements. The mining influence zones can be divided, based on their distances behind the working face, into strong disturbance zones (0–88 m), weak disturbance zones (88–142 m), and stabilized zones (>178 m). The cable bolt support system demonstrated advanced response characteristics. Compared with conventional gob-side entry retaining, the roof-cutting pressure relief technique altered stress transmission paths, significantly reduced roof load transfer efficiency, and effectively controlled roadway convergence, providing technical guidance for safe production in both this panel and mines with similar geological conditions. Full article
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21 pages, 7482 KiB  
Article
Numerical Analysis of the Aerodynamic Interactions in Tandem Flying Snake Airfoils
by Yuchen Gong, Jiacheng Guo, Alexander He, Ye Sun and Haibo Dong
Biomimetics 2025, 10(3), 174; https://doi.org/10.3390/biomimetics10030174 - 12 Mar 2025
Viewed by 745
Abstract
During gliding, flying snakes flatten their ribs to create an airfoil-like cross-section and adopt S-shape postures, allowing upstream body segments to generate wake structures that affect the aerodynamic performance of downstream segments. This study investigates these interactions using numerical simulations of two-dimensional snake [...] Read more.
During gliding, flying snakes flatten their ribs to create an airfoil-like cross-section and adopt S-shape postures, allowing upstream body segments to generate wake structures that affect the aerodynamic performance of downstream segments. This study investigates these interactions using numerical simulations of two-dimensional snake cross-sectional airfoils. By employing an immersed-boundary-method-based incompressible flow solver with tree topological local mesh refinement, various foil positions and movements were analyzed. The results show that aligning the downstream foil with the upstream foil reduces lift production by 86.5% and drag by 96.3%, leading to a 3.77-fold increase in the lift-to-drag ratio compared to a single airfoil. This improvement is attributed to the vortex–wedge interaction between the upstream vortex and the following foil’s leading edge (wedge), which enhances the gliding efficiency of the posterior body. Furthermore, integrating specific pitching motions with coordinated vortex shedding could further optimize its lift production. These findings provide valuable insights into the aerodynamics of tandem flying snake airfoils, offering guidance for configuring optimal body postures for improving gliding efficiency. Full article
(This article belongs to the Special Issue Bio-Inspired Propulsion and Fluid Mechanics)
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24 pages, 9657 KiB  
Article
Study on the Stability and Control of Gob-Side Entry Retaining in Paste Backfill Working Face
by Changtao Xu, Xiangyu Wang, Dingchao Chen, Guanghui Wang, Zhenpeng Niu and Huixing Lu
Appl. Sci. 2025, 15(2), 528; https://doi.org/10.3390/app15020528 - 8 Jan 2025
Cited by 2 | Viewed by 886
Abstract
Due to the poor stability of the roof and floor of the roadway in the 3-1 coal seam of Chahasu Coal Mine, traditional gob-side entry retaining (GER) methods fail to meet the production safety requirements. To address this, a GER technology using paste [...] Read more.
Due to the poor stability of the roof and floor of the roadway in the 3-1 coal seam of Chahasu Coal Mine, traditional gob-side entry retaining (GER) methods fail to meet the production safety requirements. To address this, a GER technology using paste backfill was proposed. This study reveals the stability mechanism of the surrounding rock in GER with paste backfill through theoretical analysis, numerical simulation, and industrial experiments. First, theoretical analysis was conducted to determine the overburden movement characteristics under varying backfill ratios. Uniaxial compressive tests on the paste material demonstrated that its bearing capacity reaches a relatively stable state after 14–28 days of curing. Second, numerical simulations were performed to study the deformation patterns of the surrounding rock and mine pressure characteristics under backfill ratios of 65%, 75%, 85%, and 95%. The Strain-Softening model was used to calibrate the backfill material parameters. The results showed that as the backfill ratio increased, the support provided by the backfill material improved, leading to enhanced bearing capacity of the overlying strata, reduced mine pressure intensity, significantly decreased deformation of the roadway, and substantially improved stability of the surrounding rock. Third, under a backfill ratio of 95%, the evolution of the abutment stress during face advancement was investigated. It was found that as the working face advanced, the backfill material and the overlying strata gradually formed a stable composite structure, with the abutment stress in the mining area stabilizing over time. Finally, to address the issue of insufficient initial strength and limited support capacity of the paste backfill material, a comprehensive control system for surrounding rock stability was proposed. This system integrates a basic bolt-mesh-cable support structure with localized reinforcement using portal hydraulic supports. Field industrial practices demonstrated that after applying this comprehensive control technology, the convergence of roof and floor was approximately 190 mm and the convergence of two ribs was about 140 mm, effectively ensuring the stability of surrounding rock in GER with paste backfill working face. Full article
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21 pages, 9366 KiB  
Article
Design of a Compliant Sternum Prosthesis for Improving Respiratory Dynamics
by Octavio Ramírez, Christopher René Torres-SanMiguel and Marco Ceccarelli
Prosthesis 2024, 6(3), 561-581; https://doi.org/10.3390/prosthesis6030040 - 28 May 2024
Cited by 2 | Viewed by 1671
Abstract
This study presents a novel approach to sternum prosthesis design, aiming to address the limitations of the current solutions by employing compliant mechanisms. The research focuses on developing a prosthetic design capable of generating lifting movements on ribs during breathing. First, a videogrammetry [...] Read more.
This study presents a novel approach to sternum prosthesis design, aiming to address the limitations of the current solutions by employing compliant mechanisms. The research focuses on developing a prosthetic design capable of generating lifting movements on ribs during breathing. First, a videogrammetry experimental test and virtual simulations were conducted to ascertain the vertical forces applied to each sternum joint. Subsequently, a compliant mechanism design was initiated, involving optimization and finite element analysis (FEM). A comprehensive kinematic performance analysis was performed to evaluate the prosthetic design. The results indicate that the obtained displacements of each rib closely align with those reported in the existing literature, demonstrating the effectiveness of the proposed solution. In conclusion, the developed sternum prosthesis exhibits the capability to recover approximately 56% of the ribs’ natural movements, highlighting its potential as an innovative and promising solution in the field of chest prosthetics. Full article
(This article belongs to the Special Issue Innovative Prosthetic Devices Applied to the Human Body)
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19 pages, 524 KiB  
Article
A Cross-Sectional Observational Pilot Study of the Main Risk Factors Related to Lower Back Pain in Spanish Hospitality Workers
by Melania Zamorano García, Gema Santamaría, Marina Seco-Casares, Ana M. Celorrio San Miguel, Eva Lantarón-Caeiro, Juan F. García and Diego Fernández-Lázaro
Safety 2024, 10(1), 12; https://doi.org/10.3390/safety10010012 - 11 Jan 2024
Viewed by 2651
Abstract
Lower back pain (LBP) describes pain of indeterminate duration between the lower edge of the ribs and the buttocks. LBP hinders movement, quality of life, and mental well-being, and limits work activities and engagement with family and friends. LBP represents a public health [...] Read more.
Lower back pain (LBP) describes pain of indeterminate duration between the lower edge of the ribs and the buttocks. LBP hinders movement, quality of life, and mental well-being, and limits work activities and engagement with family and friends. LBP represents a public health problem, and most workers are expected to experience LBP symptoms throughout their working lives. The study’s main objective was to characterize LBP in the hospitality population of the province of León, Spain, determining the risk factors. A pilot study with a cross-sectional observational design was developed following the guidelines of Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) for 150 Spanish hotel workers. Sociodemographic and lifestyle, occupational, and clinical data related to LBP were obtained through surveys. The annual prevalence of LBP in this study was 87.1% which was higher in women. A significant relationship (p < 0.05) was obtained between sex, income, smoking, sleep quality, and all labor variables with LBP. In addition, the Fear Avoidance Beliefs Questionnaire (FABQ) results revealed that 49% of the participants had a score > 14. Also, 83.3% of patients with >6 annual LBP crises suffered from sciatica. Once the results were known, preventive intervention would be needed to reduce these main risk factors for LBP for hospitality workers. Full article
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18 pages, 5175 KiB  
Article
Breathing Chest Wall Kinematics Assessment through a Single Digital Camera: A Feasibility Study
by Nunzia Molinaro, Emiliano Schena, Sergio Silvestri and Carlo Massaroni
Sensors 2023, 23(15), 6960; https://doi.org/10.3390/s23156960 - 5 Aug 2023
Cited by 3 | Viewed by 2119
Abstract
The identification of respiratory patterns based on the movement of the chest wall can assist in monitoring an individual’s health status, particularly those with neuromuscular disorders, such as hemiplegia and Duchenne muscular dystrophy. Thoraco-abdominal asynchrony (TAA) refers to the lack of coordination between [...] Read more.
The identification of respiratory patterns based on the movement of the chest wall can assist in monitoring an individual’s health status, particularly those with neuromuscular disorders, such as hemiplegia and Duchenne muscular dystrophy. Thoraco-abdominal asynchrony (TAA) refers to the lack of coordination between the rib cage and abdominal movements, characterized by a time delay in their expansion. Motion capture systems, like optoelectronic plethysmography (OEP), are commonly employed to assess these asynchronous movements. However, alternative technologies able to capture chest wall movements without physical contact, such as RGB digital cameras and time-of-flight digital cameras, can also be utilized due to their accessibility, affordability, and non-invasive nature. This study explores the possibility of using a single RGB digital camera to record the kinematics of the thoracic and abdominal regions by placing four non-reflective markers on the torso. In order to choose the positions of these markers, we previously investigated the movements of 89 chest wall landmarks using OEP. Laboratory tests and volunteer experiments were conducted to assess the viability of the proposed system in capturing the kinematics of the chest wall and estimating various time-related respiratory parameters (i.e., fR, Ti, Te, and Ttot) as well as TAA indexes. The results demonstrate a high level of agreement between the detected chest wall kinematics and the reference data. Furthermore, the system shows promising potential in estimating time-related respiratory parameters and identifying phase shifts indicative of TAA, thus suggesting its feasibility in detecting abnormal chest wall movements without physical contact with a single RGB camera. Full article
(This article belongs to the Collection Biomedical Imaging and Sensing)
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18 pages, 5450 KiB  
Article
Strata Movement and Mining-Induced Stress Identification for an Isolated Working Face Surrounded by Two Goafs
by Yingyuan Wen, Anye Cao, Wenhao Guo, Chengchun Xue, Guowei Lv and Xianlei Yan
Energies 2023, 16(6), 2839; https://doi.org/10.3390/en16062839 - 18 Mar 2023
Cited by 10 | Viewed by 1705
Abstract
Solutions for the maintenance of safety in an isolated working face has not been well achieved; this is attributed to its unique overburden structure and the strong mining-induced stress during the advancement. This paper is devoted to filling this research gap and is [...] Read more.
Solutions for the maintenance of safety in an isolated working face has not been well achieved; this is attributed to its unique overburden structure and the strong mining-induced stress during the advancement. This paper is devoted to filling this research gap and is based on the case study of LW 10304 in the Xinglongzhuang Coal Mine, in China. The overburden structure and stress distribution characteristics of this isolated working face were theoretically investigated, followed by the development of a comprehensive identification method. The research results showed the following: (1) The overburden strata of LW 10304 is in the form of a short “T” shape and the stress increment is featured with the overall “saddle” shape before the extraction of the isolated working face. During this period, the lower key strata and main key strata affect the stress level at the two ends and the central part of the working face, respectively; (2) Both the frequency and energy of micro-earthquakes in the working face account for more than 95%, which is positively correlated with roof damage and rib spalling, associated with some overlaps between the damaged zones; (3) The fracture movement of inferior key strata near the coal seam plays a dominant role in affecting microseism activity and mining-induced stress. The microseism energy attributed to roof breakage accounts for 43.34% of the overall energy; (4) A comprehensive indexing system, covering microseism frequency, microseism energy, and support resistance, was established to identify the mining-induced stress intensity of the isolated working face. The early warning efficiency of the “strong” degree of mining-induced stress is 0.94, which is believed to provide an option for other isolated working faces with similar geological and mining conditions. Full article
(This article belongs to the Special Issue New Challenges in the Utilization of Underground Energy and Space)
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10 pages, 448 KiB  
Case Report
Postoperative Osteopathic Manipulative Treatment in Children with Esophageal Atresia: Potential Benefits on the Anthropometric Parameters
by Andrea Manzotti, Alessia Alati, Matteo Galli, Francesco Cerritelli, Chiara Leva, Adele Alberti, Alessandro Stizzoli, Sara Costanzo, Carlotta Paola Maria Canonica, Francesca Destro, Gianvincenzo Zuccotti, Valeria Calcaterra and Gloria Pelizzo
Pediatr. Rep. 2022, 14(4), 434-443; https://doi.org/10.3390/pediatric14040051 - 20 Oct 2022
Viewed by 2636
Abstract
Esophageal atresia (EA) is a congenital malformation that affects the normal esophageal development. Surgical treatment, although restoring the integrity of the alimentary tract, may lead to long-term sequelae-like developmental abnormalities and musculoskeletal deformities. We evaluated the effects of osteopathic manipulative treatment (OMT) on [...] Read more.
Esophageal atresia (EA) is a congenital malformation that affects the normal esophageal development. Surgical treatment, although restoring the integrity of the alimentary tract, may lead to long-term sequelae-like developmental abnormalities and musculoskeletal deformities. We evaluated the effects of osteopathic manipulative treatment (OMT) on the recovery of the range of the right upper limb movement and on the rise of the auxological parameters. A case series of five children affected by type C EA were described. Six OMT sessions were performed over a 4-month period. At each treatment, height, weight, body mass index (BMI) and range of motion (ROM) in elevation of the right upper limb were assessed. OMT was applied to improve scar, larynx, rib cage, and sternum mobility. An average change of 2.3 cm in height and an average increase of 8° in the ROM of the upper limb in the period of study were detected. Additionally, OMT could improve the anthropometric data and the mobility of the right upper limb of children surgically treated for EA. Further studies that evaluate the effectiveness of OMT in post surgical treatment of congenital malformations of the thorax can be considered in the future. Full article
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11 pages, 4406 KiB  
Article
Assessment of Rib Fracture in Acute Trauma Using Automatic Rib Segmentation and a Curved, Unfolded View of the Ribs: Is There a Saving of Time?
by Benedikt Pregler, Lukas Philipp Beyer, Natascha Platz Batista da Silva, Sebastian Steer, Florian Zeman, Daniel Popp, Christian Stroszczynski and René Müller-Wille
J. Clin. Med. 2022, 11(9), 2502; https://doi.org/10.3390/jcm11092502 - 29 Apr 2022
Cited by 1 | Viewed by 2608
Abstract
Introduction: The fast and accurate diagnosis of rib fractures in polytrauma patients is important to reduce the mortality rate and relieve long-term pain and complications. Aim: To evaluate the diagnostic accuracy and potential time savings using automatic rib segmentation and a curved, unfolded [...] Read more.
Introduction: The fast and accurate diagnosis of rib fractures in polytrauma patients is important to reduce the mortality rate and relieve long-term pain and complications. Aim: To evaluate the diagnostic accuracy and potential time savings using automatic rib segmentation and a curved, unfolded view for the detection of rib fractures in trauma patients. Methods: The multidetector computed tomography raw data of 101 consecutive polytrauma patients (72 men; mean age 45 years, age range 17 to 84 years) admitted to a university hospital were retrospectively post-processed to generate a curved, unfolded view of the rib cage. No manual corrections were performed. Patients with reconstruction errors and movement artifacts were excluded from further analysis. All fractures were identified and classified by the study coordinator using the original data set. Two readers (reader 1 and reader 2) evaluated the original axial sections and the unfolded view, separately. The fracture locations, fracture type, and reading times were recorded. Sensitivity and specificity were calculated on a per-rib basis using a ratio estimator. Cohen’s Kappa was calculated as an index of inter-rater agreement. Results: 26 of 101 patients (25.7%) were excluded from further analysis owing to breathing artifacts (6.9%) or incorrect centerline computation in the unfolded view (18.8%). In total, 107 (5.9%) of 1800 ribs were fractured in 25 (33%) of 75 patients. The unfolded view had a sensitivity/specificity of 81%/100% (reader 1) and 71%/100% (reader 2) compared to 94%/100% (reader 1; p = 0.002/p = 0.754) and 63%/99% (reader 2; p < 0.001/p = 0.002). The sensitivity (reader 1; reader 2) was poor for buckled fractures (31%; 38%), moderate for undislocated fractures (78%; 62%), and good for dislocated fractures (94%; 90%). The assessment of the unfolded view was performed significantly faster than that of the original layers (19.5 ± 9.4 s vs. 68.6 ± 32.4 s by reader 1 (p < 0.001); 24.1 ± 9.5 s vs. 40.2 ± 12.7 s by reader 2 (p < 0.001)). Both readers demonstrated a very high interobserver agreement for the unfolded view (κ = 0.839) but only a moderate agreement for the original view (κ = 0.529). Conclusion: Apart from a relatively high number of incorrect centerline reconstructions, the unfolded view of the rib cage allows a faster diagnosis of dislocated rib fractures. Full article
(This article belongs to the Section Nuclear Medicine & Radiology)
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14 pages, 4765 KiB  
Article
Similarity Simulation on the Movement Characteristics of Surrounding Rock and Floor Stress Distribution for Large-Dip Coal Seam
by Wenxiang Cao, Honglin Liu, Yinjian Hang, Hongzhi Wang and Guodong Li
Sensors 2022, 22(7), 2761; https://doi.org/10.3390/s22072761 - 3 Apr 2022
Cited by 9 | Viewed by 2503
Abstract
The question of how to mine safely in close multi coal seams is the main concern for coal operators, in particular for large-dip coal seams with complex geological and mechanical conditions. This paper presents a detailed similarity simulation on the movement characteristics of [...] Read more.
The question of how to mine safely in close multi coal seams is the main concern for coal operators, in particular for large-dip coal seams with complex geological and mechanical conditions. This paper presents a detailed similarity simulation on the movement characteristics of the overburden and the stress distribution of underlying strata in terms of a specific coal mine in the Tielieke mining area of the Kubai coalfield via a three-dimensional photogrammetry system and a high-speed static resistance analyzer. The results show that the overburden strata are asymmetrically deformed around the coal pillar and the fracture area is perpendicular to the longwall with an “M” shape when deeper coal is mined. Moreover, the asymmetric movement of overburden results in the non-uniform distribution of stress on the floor of the coal pillar and ribs. In particular, stress is closely related to the location of the longwall, and stress of the coal pillar is much larger when it is closer to the deep side. The floor stress relief degree of the longwall in the deep zone is higher than that of its counterparts, providing a theoretical foundation for a reasonable layout and a support technique for roadways. The main contribution of this research that it can be used as a reference in maintaining the integrity of surrounding rock for large-dip coal seams with close distances. Full article
(This article belongs to the Section Intelligent Sensors)
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14 pages, 1670 KiB  
Article
The Influence of Motion on the Delivery Accuracy When Comparing Actively Scanned Carbon Ions versus Protons at a Synchrotron-Based Radiotherapy Facility
by Franciska Lebbink, Markus Stock, Dietmar Georg and Barbara Knäusl
Cancers 2022, 14(7), 1788; https://doi.org/10.3390/cancers14071788 - 31 Mar 2022
Cited by 12 | Viewed by 2557
Abstract
Motion amplitudes, in need of mitigation for moving targets irradiated with pulsed carbon ions and protons, were identified to guide the decision on treatment and motion mitigation strategy. Measurements with PinPoint ionisation chambers positioned in an anthropomorphic breathing phantom were acquired to investigate [...] Read more.
Motion amplitudes, in need of mitigation for moving targets irradiated with pulsed carbon ions and protons, were identified to guide the decision on treatment and motion mitigation strategy. Measurements with PinPoint ionisation chambers positioned in an anthropomorphic breathing phantom were acquired to investigate different tumour motion scenarios, including rib and lung movements. The effect of beam delivery dynamics and spot characteristics was considered. The dose in the tumour centre was deteriorated up to 10% for carbon ions but only up to 5% for protons. Dose deviations in the penumbra increased by a factor of two when comparing carbon ions to protons, ranging from 2 to 30% for an increasing motion amplitude that was strongly dependent on the beam intensity. Layer rescanning was able to diminish the dose distortion caused by tumour motion, but an increase in spot size could reduce it even further to 5% within the target and 10% at the penumbra. An increased need for motion mitigation of carbon ions compared to protons was identified to assure target coverage and sparing of adjacent organs at risk in the penumbra region and outside the target. For the clinical implementation of moving target treatments at a synchrotron-based particle facility complex, time dependencies needed to be considered. Full article
(This article belongs to the Special Issue Application of Proton Beam Therapy in Cancer Treatment)
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18 pages, 11410 KiB  
Article
Study on Mechanical Characteristics and Failure Modes of Coal–Mudstone Combined Body with Prefabricated Crack
by Huayong Lv, Defeng Wang, Zhanbo Cheng, Yaning Zhang and Tao Zhou
Mathematics 2022, 10(2), 177; https://doi.org/10.3390/math10020177 - 7 Jan 2022
Cited by 12 | Viewed by 1809
Abstract
There are normally pre-existing cracks that can be observed in the coal seam and immediate roof that influences the stability of the rib spalling and the movement law of overlying strata. In this study, comprehensive research methods (e.g., theory analysis, experimental tests and [...] Read more.
There are normally pre-existing cracks that can be observed in the coal seam and immediate roof that influences the stability of the rib spalling and the movement law of overlying strata. In this study, comprehensive research methods (e.g., theory analysis, experimental tests and numerical simulations) were adopted to reveal the mechanical characteristics, acoustic emission behaviors and failure modes of a coal–mudstone combined body with a single prefabricated non-penetrating crack. The results show that the influence of the crack angle on the elastic modulus of the coal–mudstone combined body samples was limited. With the increase in the crack angle, the unconfined compressive strength of samples decreased first and then increased in a V-shaped trend. In addition, the minimum unconfined compressive strength could be observed at a crack angle of 45°. Moreover, the number of acoustic emissions significantly increased with the process of continuous loading. In addition, the stress reduction zone could be observed in both ends of the prefabricated cracks at the initial stage of loading. The high- and low-stress zones were transformed with the process of continuous loading. Under an unconfined compression test, the failure models of the coal body part in the samples were mainly caused by shear failure, and only a few cracks occurred in the upper tip of the prefabricated cracks of the mudstone part. Therefore, airfoil cracks could be observed in the samples due to the strength difference of the coal mass and mudstone. Full article
(This article belongs to the Section E2: Control Theory and Mechanics)
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12 pages, 2460 KiB  
Article
Zirconia vs. Titanium Dental Implants: Primary Stability In-Vitro Analysis
by Nerea Arlucea, Aritza Brizuela-Velasco, Markel Dieguez-Pereira, Miquel Punset, Meritxell Molmeneu, Fernando Sánchez Lasheras, Hector deLlanos-Lanchares and Ángel Álvarez-Arenal
Materials 2021, 14(24), 7886; https://doi.org/10.3390/ma14247886 - 20 Dec 2021
Cited by 12 | Viewed by 3081
Abstract
The present experimental trial uses two types of dental implants, one made of titanium (Ti6Al4V) and the other one of zirconia (ZrO2), but both of identical design, to compare their stability and micro-movements values under load. One [...] Read more.
The present experimental trial uses two types of dental implants, one made of titanium (Ti6Al4V) and the other one of zirconia (ZrO2), but both of identical design, to compare their stability and micro-movements values under load. One of each type of implant (n = 42) was placed into 21 cow ribs, recording the insertion torque and the resonance frequency using a specific transducer. Subsequently, a prosthetic crown made of PMMA was screwed onto each of the implants in the sample. They were then subjected to a static compression load on the vestibular cusp of the crown. The resulting micromovements were measured. The zirconia implants obtained a higher mean of both IT and RFA when compared with those of titanium, with statistically significant differences in both cases (p = 0.0483 and p = 0.0296). However, the micromovement values when load was applied were very similar for both types, with the differences between them (p = 0.3867) not found to be statistically significant. The results show that zirconia implants have higher implant stability values than titanium implants. However, the fact that there are no differences in micromobility values implies that caution should be exercised when applying clinical protocols for zirconia based on RFA, which only has evidence for titanium. Full article
(This article belongs to the Special Issue Ti Alloys for Dental Implant Applications-Series II)
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