Effects of implantation height on the performance of a redo transcatheter aortic valve replacement using a balloon-expandable valve.

Objective: The use of the transcatheter aortic valve in low-risk patients might lead to a second intervention due to the deterioration of the first 1. Understanding the implantation height is key to an effective redo transcatheter aortic valve replacement treatment. Methods: The effects of implantation height on the performance of a balloon-expandable valve within a self-expandable valve were assessed using hemodynamic testing and particle image velocimetry. The hemodynamic performances, leaflet kinematics, and turbulent shear stresses were measured and compared. Results: When a second balloon-expandable valve was positioned at varying heights relative to the first self-expandable valve, the leaflet motion of the first valve transitioned from free opening and closing to overhanging, and eventually to being entirely pinned to the stent, forming a neo-skirt. When the leaflets of the self-expandable valve could move freely, a decrease in regurgitation fraction was observed, but with an increased pressure gradient across the valve. Flow visualization indicated that the overhanging leaflets disrupted the flow, generating a higher level of turbulence. Conclusions: This study suggests that the overhanging leaflets should be avoided, whereas the other 2 scenarios should be carefully evaluated based on an individual patient's anatomy and the cause of failure of the first valve.

Automatic Deep Learning Detection of Overhanging Restorations in Bitewing Radiographs.

OBJECTIVE: This study aimed to assess the effectiveness of deep convolutional neural network (CNN) algorithms in detecting and segmentation of overhanging dental restorations in bitewing radiographs. METHOD AND MATERIALS: A total of 1160 anonymized bitewing radiographs were used to progress the Artificial Intelligence (AI) system) for the detection and segmentation of overhanging restorations. The data was then divided into three groups: 80% for training (930 images, 2399 labels), 10% for validation (115 images, 273 labels), and 10% for testing (115 images, 306 labels). A CNN model known as you only look once (YOLOv5) was trained to detect overhanging restorations in bitewing radiographs. After utilizing the remaining 115 radiographs to evaluate the efficacy of the proposed CNN model, the accuracy, sensitivity, precision, F1 score, and area under the receiver operating characteristic curve (AUC) were computed. RESULTS: The model demonstrated a precision of 90.9%, a sensitivity of 85.3%, and an F1 score of 88.0%. Furthermore, the model achieved an AUC of 0.859 on the Receiver Operating Characteristic (ROC) curve. The mean average precision (mAP) at an intersection over a union (IoU) threshold of 0.5 was notably high at 0.87. CONCLUSION: The findings suggest that deep CNN algorithms are highly effective in the detection and diagnosis of overhanging dental restorations in bitewing radiographs. The high levels of precision, sensitivity, and F1 score, along with the significant AUC and mAP values, underscore the potential of these advanced deep learning techniques in revolutionizing dental diagnostic procedures.

Evolution Characteristics of Void in the Caving Zone Using Fiber Optic Sensing.

Addressing the issue of low filling efficiency in gangue slurry backfilling due to unclear evolution characteristics of voids in the overlying collapsed rock mass during mining, this study utilizes fiber optic sensing technology to monitor real-time strain changes within the rock mass. It proposes a void zoning method based on fiber optic sensing for mining the overlying rock and, in combination with physical model experiments, systematically investigates the dimensions, distribution, and deformation characteristics of rock mass voids. By analyzing fiber optic sensing data, the correlation between the rate of void expansion and the stress state of the rock mass is revealed. The research results demonstrate that as mining progresses, the internal voids of the rock mass gradually expand, exhibiting complex spatial distribution patterns. During the mining process, the expansion of voids within the overlying collapsed rock mass is closely related to the stress state of the rock mass. The rate of void expansion is influenced by changes in stress, making stress regulation a key factor in preventing void expansion and rock mass instability. The application of fiber optic sensing technology allows for more accurate monitoring of changes in rock mass voids, enabling precise zoning of voids in the overlying collapsed rock mass during mining. This zoning method has been validated against traditional theoretical calculations and experimental results. This research expands our understanding of the evolution characteristics of voids in overlying collapsed rock mass and provides valuable reference for backfilling engineering practices and backfilling parameter optimization.

Fungal corneal ulcer after repair of an overhanging filtering bleb: A case report.

BACKGROUND: Overhanging filtering bleb is a common complication after trabeculectomy and surgical repair is an effective treatment when the patient presents with apparent symptoms. Filtering bleb relevant infection including in the filtering bleb itself and even endophthalmitis in some severe cases has been reported. However, corneal fungal infection after filtering bleb repair is rarely reported. CASE SUMMARY: A 57-year-old Chinese man who had sensations of redness and foreign body sensations in the left eye 3 wk after repair of overhanging filtering bleb. 3 wk ago, due to sensations of a foreign body in the left eye for 3 years with worsening for 3 mo. The patient was diagnosed as overhanging filtering bleb and underwent a repair of overhanging filtering bleb. Postoperative, the filtering bleb formed well and the intraocular pressure is normal. But the patient gradually develop redness, pain and a grey infiltrate of the cornea in the eye. Finally it developed into fungal corneal ulcer. Through asking the medical history, we found the patient had irregularly self-medicated for years with glucocorticoid eye drops for years to relieve the foreign body sensation in the eye caused by filtering bleb overhanging. Because the glucocorticoid eye drops he used years ago had provide normal sensation to the eye. After 3 mo of anti-fungal treatment, the inflammation was controlled. CONCLUSION: In addition to avoiding the development of overhanging filtering bleb after trabeculectomy, the present case report also suggests that clinicians should pay more attention to the patient's ocular self-medication history. Particularly in patients with a history of glaucoma or eye surgery. Because these patients may be exposed to more types of eye drops than other individuals, they may select the wrong medications for long-term use, based on their previous experience.

Recurrence of gigantic overhanging bleb post excision: a case report.

Purpose: To report the case of an extremely large overhanging bleb, extending from superior fornix to limbus, in a 57-year-old poorly controlled diabetic, six years after trabeculectomy for an uncontrolled primary open angle glaucoma (POAG) with recurrence, months after complete excision. Methods: An overhanging bleb is defined as a filtering cicatrix which has been massaged downward over the cornea by eyelid action. It has been linked to anti-metabolite use during glaucoma filtering surgery. Despite being functional, these blebs result in patient discomfort ranging from foreign body sensation and lacrimation to dysphotopsia. A 57-year-old male presented with complaints of reduced vision, foreign body sensation, watering, and difficulty in eye closure in the left eye (OS) for past 6 months. He had undergone trabeculectomy with mitomycin C 6 years ago for advanced primary open-angle glaucoma with no follow-up beyond the initial one 4 weeks post-surgery. Results: At presentation, he had a giant multi-loculated, cystic filtering bleb (15 mm x 8 mm x 4-5 mm), which was carefully excised. Amniotic membrane was used as an anti-fibrotic as well to cover the defect. Seven months after surgery, there was recurrence of this overhanging cystic bleb when it was again excised with debulking of the conjunctiva done and cryotherapy applied to its margins. Conclusion: Although multiloculated cystic overhanging blebs have been documented before, such a large (posterior extent till fornix), thick-walled multiloculated bleb with histopathological evidence of chronic inflammatory process has not been reported prior.

A Study on the Surface Quality of Selective Laser Melted Cylindrical- and Parallelepipedic-Shaped Inner Structure.

A systematic study was conducted to investigate the distinct mechanisms involved in the formation of the inner surfaces of cylindrical and parallelepipedic-shaped structures. The surface roughness, flatness, and sinking distance were used as key indices to measure the quality of overhanging surfaces, while the surface flatness and roughness were used to evaluate the quality of the side and bottom surfaces of the inner hole. The inner surface morphology was observed using a scanning electron microscope and a white light interferometer. The test results show that the quality of the overhanging surface had a significant impact on the quality of the parallelepipedic-shaped inner hole. In contrast, the cylindrical-shaped inner hole had a shorter but more uniformly distributed overhanging surface, resulting in a different behavior of the overhanging and side surface quality. An improved model of the overhanging surface was established by combining all of the above results and comparing them with the traditional Euler Bernoulli beam model. The factors affecting the quality of the overhanging surface were analyzed, and measures for improving the quality of the overhanging surface during the SLM manufacturing process were proposed.

Radiological assessment of alveolar bone loss associated with overhanging restorations: A retrospective cone beam computed tomography study.

Background/purpose: Studies suggested that presence and size of overhanging restoration margins play role in alveolar bone loss. The aim of this study was to determine the prevalence and distribution of overhanging approximal restorations, to evaluate the effect of presence and size of overhang on bone loss using cone beam computed tomography (CBCT) reformatted panoramic images, and to encourage the use of CBCT in retrospective studies on restorative dentistry. Materials and methods: CBCT images of 382 patients with approximal restorations were included in the study. On CBCT images, alveolar bone loss adjacent to each restored surface was determined and compared to the control tooth. The overhang size was measured and categorized as small, medium, or large. Data obtained were evaluated statistically using Kruskal Wallis, Mann Whitney U, chi-square, and one-sample chi-square tests with a significance level set at P < 0.05. Results: A total of 216 (32.4%) surfaces with overhanging restorations were detected in CBCT images. The number of overhanging surfaces with alveolar bone loss (71.3%) was higher than the control surfaces with bone loss (49.1%) (P < 0.05). The amount of bone loss adjacent to overhanging surfaces (2.28 ± 1.69 mm) was significantly higher compared to control surfaces (1.53 ± 1.73 mm) (P < 0.05). However, the same trend applied to the surfaces without overhang and their controls. The amount of bone loss was not correlated with the overhang size (P > 0.05). Conclusion: Approximal restorations with and without overhanging margins may often result in alveolar bone loss, the amount of which is not always correlated with the overhang size.

AVASCULAR OVERHANGING BLEB REDUCTION WITH MODIFIED SUTURELESS TECHNIQUE.

A late postoperative trabeculectomy complication could be the overhanging bleb, especially when antimetabolites are used. It can be associated with hypotony, foreign body sensation, dellen, and visual compromise. We report a case of an avascular overhanging bleb successfully reduced with a modified sutureless technique. Nine years before, our patient had trabeculectomy using mitomycin C. After the surgery, the intraocular pressure was correct, without progression in the visual field, but on slit-lamp examination, a large avascular overhanging bleb was noted. Partial excision was performed with dissection from the cornea, overhanging conjunctival trimming, leakage checking and Bandage Contact lens placement. Topical antibiotic and steroid treatment was administered for three weeks. The excised conjunctival histopathology showed avascular metaplastic epithelium. Six months after the surgery, the patient's visual acuity improved, with intraocular pressure of 12 mm Hg and a Seidel negative asymptomatic bleb. In conclusion, this less invasive technique preserves better bleb function without ripping the surrounding ischemic tissue. The procedure is safe and easy to perform, with less surgical time and fast recovery.

A Multi-Objectives Genetic Algorithm Based Predictive Model and Strategy Optimization during SLM Process.

Selective laser melting (SLM) process was optimized in this work using multi-objectives genetic algorithm. Process parameters involved in the printing process have an obvious impact on the quality of the printed parts. As the relationship between process parameters and the quality of different parts are complex, it is quite essential to study the effect of process parameter combination. In this work, the impact of four main process parameters, including defocusing amount, laser power, scan speed and layer thickness, were studied on overhanging surface quality of the parts with different inner structures. A multiple-factor and multiple-level experiment was conducted to establish a prediction model using regression analysis while multi-objective genetic algorithm was also employed here to improve the overhanging surface quality of parts with different inner shapes accordingly. The optimized process parameter combination was also used to print inner structure parts and compared with the prediction results to verify the model we have obtained before. The prediction results revealed that sinking distance and roughness value of the overhanging surface on a square-shape inner structure can reduce to 0.017 mm and 9.0 µm under the optimal process parameters combination, while the sinking distance and roughness value of the overhanging surface on a circle-shape inner structure can decrease to 0.014 mm and 10.7 µm under the optimal process parameters combination respectively. The testing results showed that the error rates of the prediction results were all within 10% in spite of random powder bonding in the printing process, which further proved the reliability of the previous results.

Bleb revision with bleborhexis and clear corneal lamellar patch graft for overhanging cystic bleb.

Background: Trabeculectomy is associated with several complications. One of the common complications with mitomycin assisted trabeculectomy is thin cystic bleb leading to bleb leak, hypotony and infections. Various technique of bleb repair and reconstruction have been described, such as conjunctival advancement, or scleral, pericardial or corneal patch graft. Purpose: To demonstrate bleb revision by bleborhexis and clear corneal lamellar patch graft for a patient with thin cystic leaking bleb leading to hypotony and decreased vision. Synopsis: This was a 75-year-old one-eyed lady, diagnosed with primary angle-closure glaucoma in both eyes with absent light perception in the left eye, had undergone a combined trabeculectomy and cataract surgery in the right eye 6 years ago. She presented with diminution of vision (6/18p), introacular pressure (IOP) of of 6 mmHg, thin cystic leaking overhanging bleb, and dysesthesia. Bleb repair by bleborhexis with lamellar corneal patch graft was performed. Bleborhexis is a technique in which the overhanging fibrosed thin cystic conjunctival bleb is peeled off the cornea smoothly to leave a uniform clear corneal surface. Clear cornea, uniform diffuse bleb, well-formed anterior chamber with and IOP of 15 mmHg was noted on the first post-operative day, with a vision of 6/12p. This procedure helped meticulous reconstruction of the bleb, early recovery of vision, maintanance of normotensive eye, and save the eye from potential infections. Highlights: Bleborhexis with lamellar corneal patch graft provides for an easy and a elegant surgical technique with minimal corneal tissue damage, faster healing and patient comfort. It could be the favored technique in patients with thin overhanging clebs. Video link: https://youtu.be/GeFYHWToueU.

Is standard total knee arthroplasty with lateral femoral overhanging a cause of anterior knee pain? A randomized controlled trial.

INTRODUCTION: Anterior knee pain (AKP) may persist after total knee arthroplasty (TKA), even if well aligned and stable, and is reported in up to 30% of patients, leading to patient dissatisfaction. The gender-specific knee prostheses have been designed to reduce femoral component overhanging in females and improve patient satisfaction. The purpose of this study was to determine AKP between gender-specific knee prosthesis and unisex knee prosthesis following minimally invasive surgery (MIS) TKA with patellar resurfacing. METHODS: This study was a randomized trial comparing a gender-specific vs. unisex knee prosthesis in females with knee osteoarthritis. Follow-up occurred at 6 weeks, 3 months, 6 months, 1 year, and 2 years. Pre- and postoperative AKP were measured at each follow-up. Intraoperative lateral overhanging of the femoral component and patellar tracking were also measured and compared between the two groups. RESULTS: Sixty females were recruited; 30 underwent gender-specific knee prosthesis (Gp1) and 30 underwent unisex knee prosthesis (Gp2). No patients were lost to follow-up. The incidence rates of AKP and visual analog scale AKP pain scores at 2 years were 7 vs. 7% (p = 1.00) and 0.95 ± 0.31 (0-1) points vs. 1.10 ± 0.28 (0-1) points (p = 0.68) for gender and unisex prostheses, respectively. Patellar tilt and patellar shift were similar between the two groups. Patellar tilt and patellar shift were 2.56° ± 2.03 (0-8) vs. 2.67° ± 2.35 (0-9) (p = 0.46) and 1.25 ± 1.09 (0-3.2) mm vs. 1.15 ± 0.97 (0-2.9) mm (p = 0.34) for Gp1 and Gp2, respectively. Mean lateral femoral overhanging was 0.23 ± 0.63 mm (range: 1-2 mm, Gp1) vs. 1.57 ± 1.36 mm (range: 1-3 mm, Gp2) (p ≤ 0.001). CONCLUSION: Both types of prostheses had similar incidence rates of AKP, VAS scores for AKP. Lateral femoral overhanging of ≤ 3 mm was not the cause of AKP.

A mathematical determination of foveal attachment in primary rhegmatogenous retinal detachment when obscured by bullous retina.

In primary rhegmatogenous retinal detachment (RRD), the foveal attachment is an important prognostic factors for post-operative vision. When the fovea is obscured by the RRD, its attachment status is considered uncertain. Using a model of the reduced emmetropic and - 10 dioptre myopic eye and the physical properties of the detached retina, we aimed to mathematically ascertain if it is clinically possible for the fovea to be attached while it is obscured by the primary RRD. With the patient upright, a primary RRD due to a 12 o'clock break directly above the fovea was considered. Mathematically, once the trough of the RRD touches the visual axis the edge of the RRD nearest to fovea is [Formula: see text] away from fovea in emmetropic eye and [Formula: see text] in myopic eye. When the RRD reaches the fovea, its trough is [Formula: see text] below the visual axis in emmetropic eye and [Formula: see text] in myopic eye. However, in vivo the RRD makes an acute angle with the retinal pigment epithelium and the corrugation of the retina in RRD shortens the retina. When these in vivo constraints are considered, in both of the above situations the fovea will be detached. If the fovea is obscured by an RRD, the fovea is very likely to be detached. In idiomatic terms, if the fovea cannot be seen, the fovea cannot see. This is an important clinical diagnosis for appropriate triage of the patient.

An alternative approach to study irrotational periodic gravity water waves.

We are concerned here with an analysis of the nonlinear irrotational gravity water wave problem with a free surface over a water flow bounded below by a flat bed. We employ a new formulation involving an expression (called flow force) which contains pressure terms, thus having the potential to handle intricate surface dynamic boundary conditions. The proposed formulation neither requires the graph assumption of the free surface nor does require the absence of stagnation points. By way of this alternative approach we prove the existence of a local curve of solutions to the water wave problem with fixed flow force and more relaxed assumptions.

Efficient Design of a Clear Aligner Attachment to Induce Bodily Tooth Movement in Orthodontic Treatment Using Finite Element Analysis.

Clear aligner technology has become the preferred choice of orthodontic treatment for malocclusions for most adult patients due to their esthetic appeal and comfortability. However, limitations exist for aligner technology, such as corrections involving complex force systems. Composite attachments on the tooth surface are intended to enable active control of tooth movements. However, unintended tooth movements still occur. In this study, we present an effective attachment design of an attachment that can efficiently induce tooth movement by comparing and analyzing the movement and rotation of teeth between a general attachment and an overhanging attachment. The 3D finite element modes were constructed from CBCT data and used to analyze the distal displacement of the central incisor using 0.5- and 0.75-mm-thick aligners without an attachment, and with general and overhanging attachments. The results show that the aligner with the overhanging attachment can effectively reduce crown tipping and prevent axial rotation for an intended distal displacement of the central incisor. In all models, an aligner with or without attachments was not capable of preventing the lingual inclination of the tooth.

Influence of Overhanging Bleb on Corneal Higher-Order Aberrations after Trabeculectomy.

Recent advances in ocular aberrometry have revealed that ocular surgery increases ocular and corneal higher-order aberrations. This retrospective single-center study aimed to examine the effects of the overhanging bleb on corneal higher-order aberrations using a wavefront analyzer. We included 61 eyes from 50 patients with overhanging bleb after trabeculectomy with a fornix-based conjunctival flap using mitomycin C (overhanging bleb group) and 65 eyes from 54 glaucoma patients with no history of glaucoma surgery (control group). Corneal higher-order aberrations (total higher-order aberrations, coma aberrations, coma-like aberrations, spherical aberrations, and spherical-like aberrations) on a 4 mm pupil diameter were measured using the TOPCON KR-1W wavefront analyzer. Corneal coma aberrations were higher in the overhanging bleb group than in the control group (0.16 ± 0.13 µm and 0.10 ± 0.05 µm, respectively; p = 0.042). Corneal coma-like aberrations were also higher in the overhanging bleb group than in the control group (0.31 ± 0.32 µm and 0.16 ± 0.09 µm, respectively; p = 0.022). With an increasing ratio of cornea covered by the bleb to the entire cornea, all corneal higher-order aberrations increased except for corneal coma-like aberrations. Overhanging bleb after trabeculectomy with a fornix-based conjunctival flap using mitomycin C and its size influenced corneal higher-order aberrations.

A High-Performance Flexible Pressure Sensor Realized by Overhanging Cobweb-like Structure on a Micropost Array.

Recent years have seen a rapid development of electronic skin for wearable devices, autonomous robotics, and human-machine interaction. As a result, the demand for flexible pressure sensors as the critical sensing element in electronic skin is also increasing. These sensors need to feature high sensitivity, short response time, low detection limit, and so on. In this paper, inspired from the cobweb in nature, we propose a piezoresistive pressure sensor by forming a cobweb-like network made of a zinc octaethylphorphyrin (ZnOEP)/carbon nanotube (CNT) hybrid on an array of polydimethylsiloxane (PDMS) microposts. The hybrid material exhibits excellent adhesion to PDMS, benefitting from ZnOEP's low Young's modulus and the nonpolar bonding between ZnOEP and PDMS such that no delamination and resistance variation are found after thousands of cycles of bending and twisting. With the overhanging morphology of the ZnOEP/CNT network on the micropost array, we realized a pressure sensor with an ultrahigh sensitivity of 39.4 kPa-1, a super-fast response time of 3 ms, a low detection limit of 10 Pa, and a reproducible response without degradation after 5000 cycles of pressure loading/unloading. The sensor can be employed for a variety of applications, including wrist pulse measurement, sound level detection, mechanical vibration monitoring, etc., proving its great potential for use in electronic skin systems.

Stapedectomy in patients with dehiscent and prolapsed facial nerve.

OBJECTIVE: The aim of this study is to apply the modified stapedectomy technique in cases with dehiscent and prolapsed facial nerve canal, and to compare the postoperative results with those with normal facial nerve canal anatomy. MATERIAL AND METHOD: 28 patients who underwent primary stapedectomy were included. Of the patients, 17 were in the normal anatomical facial nerve group, and 11 were in the dehiscent and prolapsed facial nerve group. Facial nerve was retracted with micro elevator in dehiscent and prolapsed group. and Titanium-Teflon prosthesis was angled and used in accordance with facial nerve course at this group. RESULT: No facial paresis or paralysis was observed in any patient postoperatively. In the first year, no significant difference was found in terms of air-bone gap. CONCLUSION: It is safe to retract the facial nerve for a limited time in cases of stapedectomy in cases with dehiscent and prolapsed facial nerve canal. In these cases, modifying the stapedial prosthesis in accordance with the facial nerve course does not cause disadvantage in terms of hearing gain.

Modified osteotomy of posterolateral overhanging part of the trochanter via posterior approach for hip arthroplasty: an anatomical study.

BACKGROUD: The osteotomy of the posterolateral overhanging part (PLOP) of the greater trochanter via posterior approach has been used for the hip arthroplasty for decades with good results. However, the osteotomy method remains undefined and the precise adjacent structures around PLOP have not been reported. The purpose of this study was to present a modified PLOP osteotomy approach and perform a detailed study of the topographic and surgical anatomy of the PLOP. METHODS: The peri-PLOP soft tissue and the bony parameters were measured using 10 cadavers with 20 hips and 20 skeletal hip specimens, respectively. RESULTS: A 1.8-cm vertical osteotomy did not jeopardize the femoral neck, and a 1.8-cm wide bone block did not damage the insertions of the short external rotators. The average distances between the most distal branch of the superior gluteal nerve/artery and the 1.8-cm point of the greater trochanter were 5.70 ± 0.66 cm and 6.33 ± 0.56 cm, respectively. CONCLUSION: For osteotomy of the PLOP, we suggested that the width of the upper side from the lateral to medial greater trochanter should be 1.8 cm, depth of vertical osteotomy should be 1.8 cm, and length of the posterior edge should be 4 cm. Obturator externus tendon should be kept within the bone block of osteotomy. The proximal extension of the gluteus medius muscle split should be limited to 5.5 cm at the 1.8 cm-point of the greater trochanter. LEVEL OF EVIDENCE: Prospective comparative study Level II.

Highly efficient gene silencing in mouse brain by overhanging-duplex oligonucleotides via intraventricular route.

Gapmer-type antisense oligonucleotides have not yet been approved for the treatment of central nervous system diseases, whereas steric-blocking-type antisense oligonucleotides have been well-developed for clinical use. We here characterize a new type of double-stranded oligonucleotides, overhanging-duplex oligonucleotides, which are composed of the parent gapmer and its extended complementary RNA. By intracerebroventricular injection, overhanging oligonucleotides show greater silencing potency with more efficient delivery into mouse brains than the parent single-stranded gapmer. Structure-activity relationship analyses reveal that the potency enhancement requires 13-mer or more overhanging oligonucleotides with a phosphorothioate backbone. Overhanging oligonucleotides provide a new platform of therapeutic oligonucleotides for gene modulation in the central nervous system.