Critical Structures Research Articles

Dynamic‐Bond‐Mediated Chain Reptation Enhances Energy Dissipation of Elastomers

AbstractVibrations with various frequencies in daily life and industry can cause health hazards and fatigue failure of critical structures, which requires the development of elastomers with high energy dissipation at desired frequencies. Current strategies relying on tuning characteristic relaxation time of polymer chains are mostly qualitative empirical methods, and it is difficult to precisely control damping performances. Here, we report a general strategy for constructing dynamic crosslinked polymer fluid gels that provide controllable ultrahigh energy dissipation. This is realized by dynamic‐bond‐mediated chain reptation of polymer fluids in a crosslinked network, where the characteristic time of chain reptation is dominated by the presence of well‐defined dissociation time of dynamic bonds and almost independent of their molar mass. Using prototypical supramolecular polydimethylsiloxane elastomers, we demonstrate that dynamic crosslinked polymer fluid gels exhibit a controllable ultrahigh damping performance at desired frequencies (10−2~102 Hz), exceeding that of typical state‐of‐the‐art silicone damping materials. Their shock absorption is over 300 % higher than that of commercial silicone rubber under the same impact force.

Dynamic-Bond-Mediated Chain Reptation Enhances Energy Dissipation of Elastomers.

Vibrations with various frequencies in daily life and industry can cause health hazards and fatigue failure of critical structures, which requires the development of elastomers with high energy dissipation at desired frequencies. Current strategies relying on tuning characteristic relaxation time of polymer chains are mostly qualitative empirical methods, and it is difficult to precisely control damping performances. Here, we report a general strategy for constructing dynamic crosslinked polymer fluid gels that provide controllable ultrahigh energy dissipation. This is realized by dynamic-bond-mediated chain reptation of polymer fluids in a crosslinked network, where the characteristic time of chain reptation is dominated by the presence of well-defined dissociation time of dynamic bonds and almost independent of their molar mass. Using prototypical supramolecular polydimethylsiloxane elastomers, we demonstrate that dynamic crosslinked polymer fluid gels exhibit a controllable ultrahigh damping performance at desired frequencies (10-2~102 Hz), exceeding that of typical state-of-the-art silicone damping materials. Their shock absorption is over 300 % higher than that of commercial silicone rubber under the same impact force.

409 Automated Prediction of Bone Volume Removed During Cortical Mastoidectomy Using Deep Learning

OBJECTIVES/GOALS: Patient-specific definition of extent of surgical excision is foundational to the safety offered by computer assisted interventions. Consequently, this study aims to develop a pipeline for automated segmentation of bone removed during cortical mastoidectomy, a technically complex otologic surgery. METHODS/STUDY POPULATION: A simulator, previously developed in our lab, allows fully immersive simulation of mastoidectomy using segmented temporal bones generated from CT data. Using the simulator, one attending surgeon will perform three trials of mastoidectomy on 20 different temporal bones. From the simulator we will obtain data on the volume of bone removed for a specific anatomy, averaged between trials. No new U-net (nnU-net), an open-source three-dimensional segmentation network, will then be trained to predict the volume of bone removed using segmented pre-operative CT imaging. Segmentation accuracy will be evaluated with the Dice coefficient, modified Hausdorff distance (mHD), sensitivity and specificity. RESULTS/ANTICIPATED RESULTS: We expect the mean pairwise Dice coefficient to be high indicating relative similarity of volume removed between trials. Moreover, we predict that following five-fold cross-validation the best model will result in a Dice coefficient, mHD, sensitivity, and specificity indicative of volume removed predictions consistent with surgeon-generated data. Finally, given that network training will penalize overlap of the predicted excised bone segment and previously segmented anatomic structures, we expect that no critical anatomical structures will be marked as tissue removed. DISCUSSION/SIGNIFICANCE: We hope to show that deep learning architectures can accurately predict bone removed during mastoidectomy. These predictions can be used for preoperative planning, as clinical endpoints in surgical simulators, or be used in conjunction with surgical robots, all ultimately improving patient safety.

SIRT1 coordinates transcriptional regulation of neural activity and modulates depression-like behaviors in the nucleus accumbens

BackgroundMajor depression and anxiety disorder are significant causes of disability and socio-economic burden. Despite the prevalence and considerable impact of these affective disorders, their pathophysiology remains elusive. Thus, there is an urgent need to develop novel therapeutics for these conditions. We evaluated the role of SIRT1 in regulating dysfunctional processes of reward by using chronic social defeat stress (CSDS) to induce depression- and anxiety-like behaviors. CSDS induces physiological and behavioral changes that recapitulate depression-like symptomatology and alters gene expression programs in the nucleus accumbens, yet cell type-specific changes in this critical structure remain largely unknown. MethodsWe examined transcriptional profiles of D1-MSNs lacking deacetylase activity of SIRT1 by RNA sequencing (RNA-Seq) in a cell-type specific manner using the RiboTag line of mice. We analyzed differentially expressed genes using gene ontology tools including SynGO and EnrichR, and further demonstrated functional changes in D1-MSN specific SIRT1-KO mice using electrophysiological and behavioral measurements. ResultsRNAseq revealed altered transcriptional profiles of D1-MSNs lacking functional SIRT1 and showed specific changes in synaptic genes including glutamatergic and GABAergic receptors in D1-MSNs. These molecular changes may be associated with decreased excitatory and increased inhibitory neural activity in Sirt1-KO D1-MSNs, accompanied by morphological changes. Moreover, the D1-MSN-specific Sirt1-KO mice exhibited pro-resilient changes in anxiety- and depression-like behaviors. ConclusionsSIRT1 coordinates excitatory and inhibitory synaptic genes to regulate GABAergic output tone of D1-MSNs. These findings reveal a novel signaling pathway that has the potential for the development of innovative treatments for affective disorders.

Motion-Inclusive Treatment Planning to Assess Normal Tissue Dose for Central Lung Stereotactic Body Radiation Therapy

PurposeFor lung SBRT, 4DCT is often used to delineate target volumes, whereas organs at risk (OARs) are typically outlined on either average intensity projection (AIP) or mid-ventilation (MidV = 30% phase) images. AIP has been widely adopted as it represents a true average, but image blurring often precludes accurate contouring of critical structures such as central airways. Here we compare AIP vs MidV planning for centrally located tumors via respiratory motion-inclusive (RMI) plans to better evaluate dose delivered throughout the breathing cycle. MethodsIndependently contoured and optimized AIP and MidV plans were created for 16 treatments and rigidly copied to each of the 10 breathing phase-specific CT image sets. Resulting dose distributions were deformably registered back to the MidV image set (used as reference due to clearer depiction of anatomy compared to motion-blurred AIP) and averaged to create RMI plans. Doses to central OARs were compared between plans. ResultsMean absolute dose differences were low for all comparisons (range 0.01 – 2.87 Gy), however, individual plans exhibited differences > 20 Gy. Dose differences >5 Gy were observed most often for plan comparisons involving AIP-based plans (MidV vs AIP 23, AIP RMI vs AIP 12, MidV RMI vs AIP RMI 7, and MidV RMI vs MidV 8 times). Inclusion of respiratory motion reduced large dose differences. Standard OAR thresholds were exceeded up to five times for each plan comparison scenario and always involved PBT D4cc tolerance dose. AIP-based contours were larger by on average 3-15%. ConclusionLarge dose differences were observed when plans with AIP-based contours were compared with MidV-based contours indicating that observed dose differences were likely due to contoured volume differences rather than the effect of motion. Because of blurring with AIP images, MidV RMI-based planning may offer a more accurate method to determine dose to critical OARs in the presence of respiratory motion.

Recent studies on the mechanical properties of Engineered Cementitious Composite

Engineered Cementitious Composite (ECC) is a type of High-Performance Fiber-Reinforced Cementitious Composite (HPFRCC) that has emerged as a promising material for use in construction and engineering. ECC is designed based on micromechanical theory, resulting in a remarkable tensile strain capacity of over 6%, while maintaining a low fiber volume fraction of no more than 2%. The material’s high flexibility enables it to be molded into various shapes, and it exhibits excellent mechanical properties, making it suitable for field applications such as the construction of joint-less deck slabs, link slabs, and retrofitting of critical structures like dams and tunnels. However, the accurate characterization of ECC’s properties requires the use of appropriate testing methods, particularly regarding its mechanical characteristics, including compressive strength, flexural strength, and direct and indirect tensile strength. This review highlights the significance of understanding ECC’s mechanical properties and emphasizes the importance of using appropriate testing techniques to evaluate the material’s properties and structural behavior.

Factors that support public health infrastructure recovery in Puerto Rico and US Virgin Islands after Hurricanes Irma and Maria.

This paper describes the factors that support recovery of public health infrastructure (PHI), including conditions that facilitated or hindered recovery in United States (US) territories impacted by hurricanes Irma and Maria. A deductive approach was used to categorize data from five organizations that received crisis hurricane recovery (CHR) funds from the Centers for Disease Control and Prevention.* Spending was grouped into five infrastructure gaps: (1) human resources, (2) informatic upgrades, (3) equipment, (4) minor repairs, and (5) preventive maintenance. Unanticipated PHI costs, facilitators, and hinderances to PHI recovery were identified. Most (72 percent) of the $53,529,823 CHR funding was used to address infrastructure gaps in (1) human resources (56 percent), (2) informatics (16 percent), (3) equipment (13 percent), (4) minor repairs (10 percent), and (5) preventive maintenance (5 percent). Most of the requests (56 percent) to redirect funds were associated with unanticipated costs in initial work plans and budgets. The use of administrative partners, planning tools, dedicated staff, streamlined procedures, eg, contracts, and cost sharing facilitated PHI recovery. The most common hindrance to PHI recovery were delays in procurement and shipping. In summary, investments in dedicated funding to upgrade, repair, or replace critical structures and systems for infectious disease surveillance, laboratory capacity, vector control, environmental health inspections, and vaccine storage and administration in Puerto Rico and the US Virgin Islands after Hurricanes Irma and Maria contributed to their recovery capacity. These findings may inform funding and resource allocation considerations for PHI recovery in the US territories.

Clinical Application of an Augmented Reality Navigation System for Transforaminal Epidural Injection: A Randomized Controlled Trial.

Objectives: Augmented reality (AR) navigation systems are emerging to simplify and enhance the precision of medical procedures. Lumbosacral transforaminal epidural injection is a commonly performed procedure for the treatment and diagnosis of radiculopathy. Accurate needle placement while avoiding critical structures remains a challenge. For this purpose, we conducted a randomized controlled trial for our augmented reality navigation system. Methods: This randomized controlled study involved 28 patients, split between a traditional C-arm guided group (control) and an AR navigation guided group (AR-NAVI), to compare procedure efficiency and radiation exposure. The AR-NAVI group used a real-time tracking system displaying spinal structure and needle position on an AR head-mounted display. The procedural time and C-arm usage (radiation exposure) were measured. Results: All patients underwent successful procedures without complications. The AR-NAVI group demonstrated significantly reduced times and C-arm usage for needle entry to the target point (58.57 ± 33.31 vs. 124.91 ± 41.14, p < 0.001 and 3.79 ± 1.97 vs. 8.86 ± 3.94, p < 0.001). Conclusions: The use of the AR navigation system significantly improved procedure efficiency and safety by reducing time and radiation exposure, suggesting a promising direction for future enhancements and validation.

Nanoscale mechanisms of carboxyl carbon preservation during Fe(II)-induced ferrihydrite transformation

The persistence of organic carbon (OC) in natural environments is widely attributed to OC associations with minerals such as iron (Fe) minerals. Carboxyl, a critical structure of OC, can form strong complexes with Fe minerals, but it is still largely unknown about the effects of carboxyl groups on the transformation of Fe oxides and the stabilization mechanisms of OC on Fe oxides at nanoscales. In this study, four carboxylic acids with varying numbers of carboxyl groups (2, 3, 4, and 27 carboxyls) and molecular weight (ranging from 100 to 2000 Da) were added during the coprecipitation of Fe oxides and OC. This approach was taken to systematically elucidate the nanoscale distribution and sequestration mechanisms of carboxyl-containing OC on Fe oxides over different aging periods. Results suggested that ferrihydrite transformed quickly into lepidocrocite, goethite, and magnetite with the presence of Fe(II). The transformation rate of lepidocrocite to goethite slowed with increasing carboxyl number in OC molecules for the low molecular weight carboxylic acids (100–300 Da), but the high molecular weight carboxylic acid (∼2000 Da) promoted ferrihydrite transformation into goethite. Meanwhile, the particle sizes of produced magnetite decreased with increasing carboxyl number in OC molecules. During the mineral transformation, the release of OC from Fe oxides to aqueous solution decreased with increasing numbers of carboxyl groups. Spherical aberration corrected scanning transmission electron microscopy (Cs-STEM) coupled with electron-energy-loss spectroscopy (EELS) suggested that carboxyl-rich OC promoted the formation of abundant defective or porous structures in goethite, resulting in OC accumulation in the bulk areas of goethite, which provided an effective way to sequester OC. The aggregation of high molecular weight OC containing more carboxyl groups with magnetite nanoparticles also played an important role in the preservation of OC. Furthermore, Fourier-transform infrared spectroscopy (FTIR) and near edge X-ray absorption fine structure spectroscopy (NEXAFS) indicated that OC may form bidentate binding with Fe oxides and the binding strength of Fe(III) and OC may change with varying numbers of carboxyl groups. Results in this study provided a comprehensive understanding of the dynamic interactions between OC with different numbers of carboxyl groups and Fe oxides, and shed insights into the nanoscale mechanisms of OC stabilization during Fe oxide transformation process.

Contribution of pudendal nerve injury to stress urinary incontinence in a male rat model

Urinary incontinence is a common complication following radical prostatectomy, as the surgery disturbs critical anatomical structures. This study explored how pudendal nerve (PN) injury affects urinary continence in male rats. In an acute study, leak point pressure (LPP) and external urethral sphincter electromyography (EMG) were performed on six male rats with an intact urethra, the urethra exposed (UE), the PN exposed (NE), and after PN transection (PNT). In a chronic study, LPP and EMG were tested in 67 rats 4 days, 3 weeks, or 6 weeks after sham PN injury, PN crush (PNC), or PNT. Urethras were assessed histologically. Acute PNT caused a significant decrease in LPP and EMG amplitude and firing rate compared to other groups. PNC resulted in a significant reduction in LPP and EMG firing rate 4 days, 3 weeks, and 6 weeks later. EMG amplitude was also significantly reduced 4 days and 6 weeks after PNC. Neuromuscular junctions were less organized and less innervated after PNC or PNT at all timepoints compared to sham injured animals. Collagen infiltration was significantly increased after PNC and PNT compared to sham at all timepoints. This rat model could facilitate preclinical testing of neuroregenerative therapies for post-prostatectomy incontinence.

Financial stability of Ukraine's economy during the war and post-war periods: challenges and drivers of recovery

The article highlights the issues related to the challenges and drivers of recovery of the economy of Ukraine in the war and post-war periods. It is noted that since the beginning of the full-scale invasion of the Russian Federation on the territory of Ukraine, our country has lost significant human resources and witnessed the destruction of critical, industrial and social structures. The hostilities continue, but the belief in victory prompts scholars and practitioners to discuss the formats of reconstruction and modernization of the country after the war.&#x0D; Directions of economic recovery are proposed, namely: reconstruction and restoration of war-damaged property and infrastructure; quick recovery of economic processes; return of refugees and internally displaced persons back to Ukraine and their inclusion in economic processes; creating the foundations for sustainable economic growth. It has been concluded that, in general, the recovery of the economy of Ukraine, which suffered from the war, can be a driver of the recovery of infrastructure and revival of the industrial sector, creation of new jobs and support of small and medium enterprises, reconstruction of the housing stock, restoration of social infrastructure and development of the sphere of social services, social rehabilitation of war victims and restoration of the natural environment.

Developing and validating a simple urethra surrogate model to facilitate dosimetric analysis to predict genitourinary toxicity

PurposeThe urethra is a critical structure in prostate radiotherapy planning; however, it is impossible to visualise on CT. We developed a surrogate urethra model (SUM) for CT-only planning workflow and tested its geometric and dosimetric performance against the MRI-delineated urethra (MDU). MethodsThe SUM was compared against 34 different MDUs (within the treatment PTV) in patients treated with 36.25Gy (PTV)/40Gy (CTV) in 5 fractions as part of the PACE-B trial. To assess the surrogate's geometric performance, the Dice similarity coefficient (DSC), Hausdorff distance (HD), mean distance to agreement (MDTA) and the percentage of MDU outside the surrogate (UOS) were calculated. To evaluate the dosimetric performance, a paired t-test was used to calculate the mean of differences between the MDU and SUM for the D99, D98, D50, D2 and D1. The D(n) is the dose (Gy) to n% of the urethra. ResultsThe median results showed low agreement on DSC (0.32; IQR 0.21–0.41), but low distance to agreement, as would be expected for a small structure (HD 8.4mm (IQR 7.1–10.1mm), MDTA 2.4mm (IQR, 2.2mm-3.2mm)). The UOS was 30% (IQR, 18–54%), indicating nearly a third of the urethra lay outside of the surrogate. However, when comparing urethral dose between the MDU and SUM, the mean of differences for D99, D98 and D95 were 0.12Gy (p=0.57), 0.09Gy (p=0.61), and 0.11Gy (p=0.46) respectively. The mean of differences between the D50, D2 and D1 were 0.08Gy (p=0.04), 0.09Gy (p=0.02) and 0.1Gy (p=0.01) respectively, indicating good dosimetric agreement between MDU and SUM. ConclusionWhile there were geometric differences between the MDU and SUM, there was no clinically significant difference between urethral dose-volume parameters. This surrogate model could be validated in a larger cohort and then used to estimate the urethral dose on CT planning scans in those without an MRI planning scan or urinary catheter.

Impaired olfactory identification in dementia-free individuals is associated with the functional abnormality of the precuneus

ObjectiveOlfactory dysfunction indicates a higher risk of developing dementia. However, the potential structural and functional changes are still largely unknown. MethodsA total of 236 participants were enrolled, including 45 Alzheimer's disease (AD) individuals and 191dementia-free individuals. Detailed study methods, comprising neuropsychological assessment and olfactory identification test (University of Pennsylvania smell identification test, UPSIT), as well as structural and functional magnetic resonance imaging (MRI) were applied in this research. The dementia-free individuals were divided into two sub-groups based on olfactory score: dementia-free with olfactory dysfunction (DF-OD) sub-group and dementia-free without olfactory dysfunction (DF-NOD) sub-group. The results were analyzed for subsequent intergroup comparisons and correlations. The cognitive assessment was conducted again three years later. Results(i) At dementia-free stage, there was a positive correlation between olfactory score and cognitive function. (ii) In dementia-free group, the volume of crucial brain structures involved in olfactory recognition and processing (such as amygdala, entorhinal cortex and basal forebrain volumes) are positively associated with olfactory score. (iii) Compared to the DF-NOD group, the DF-OD group showed a significant reduction in olfactory network (ON) function. (iv) Compared to DF-NOD group, there were significant functional connectivity (FC) decline between PCun_L(R)_4_1 in the precuneus of posterior default mode network (pDMN) and the salience network (SN) in DF-OD group, and the FC values decreased with falling olfactory scores. Moreover, in DF-OD group, the noteworthy reduction in FC were observed between PCun_L(R)_4_1 and amygdala, which was a crucial component of ON. (v) The AD conversion rate of DF-OD was 29.41%, while the DF-NOD group was 12.50%. The structural and functional changes in the precuneus were also observed in AD and were more severe. ConclusionsIn addition to the olfactory circuit, the precuneus is a critical structure in the odor identification process, whose abnormal function underlies the olfactory identification impairment of dementia-free individuals.

Techniques for Thyroidectomy and Functional Neck Dissection.

Thyroidectomy is a commonly performed surgery for thyroid cancer, Graves' disease, and thyroid nodules. With the increasing incidence of thyroid cancer, understanding the anatomy and surgical techniques is crucial to ensure successful outcomes and minimize complications. This review discusses the anatomical considerations of the thyroid and neck, including lymphatic drainage and the structures at risk during thyroidectomy. Emphasis is placed on the significance of cautious dissection to preserve critical structures, such as the parathyroid glands and recurrent laryngeal nerve. Neck dissection is also explored, particularly in cases of lymph node metastasis, in which its proper execution is essential for better survival rates. Additionally, this review evaluates various thyroidectomy techniques, including minimally invasive approaches, highlighting their potential benefits and limitations. Continuous surgical knowledge and expertise updates are necessary to ensure the best results for patients undergoing thyroidectomy.

PitSurgRT: real-time localization of critical anatomical structures in endoscopic pituitary surgery.

Endoscopic pituitary surgery entails navigating through the nasal cavity and sphenoid sinus to access the sella using an endoscope. This procedure is intricate due to the proximity of crucial anatomical structures (e.g. carotid arteries and optic nerves) to pituitary tumours, and any unintended damage can lead to severe complications including blindness and death. Intraoperative guidance during this surgery could support improved localization of the critical structures leading to reducing the risk of complications. A deep learning network PitSurgRT is proposed for real-time localization of critical structures in endoscopic pituitary surgery. The network uses high-resolution net (HRNet) as a backbone with a multi-head for jointly localizing critical anatomical structures while segmenting larger structures simultaneously. Moreover, the trained model is optimized and accelerated by using TensorRT. Finally, the model predictions are shown to neurosurgeons, to test their guidance capabilities. Compared with the state-of-the-art method, our model significantly reduces the mean error in landmark detection of the critical structures from 138.76 to 54.40 pixels in a 1280 720-pixel image. Furthermore, the semantic segmentation of the most critical structure, sella, is improved by 4.39% IoU. The inference speed of the accelerated model achieves 298 frames per second with floating-point-16 precision. In the study of 15 neurosurgeons, 88.67% of predictions are considered accurate enough for real-time guidance. The results from the quantitative evaluation, real-time acceleration, and neurosurgeon study demonstrate the proposed method is highly promising in providing real-time intraoperative guidance of the critical anatomical structures in endoscopic pituitary surgery.

Data‐driven disturbance compensation control for discrete‐time systems based on reinforcement learning

SummaryIn this article, a self‐learning disturbance compensation control method is developed, which enables the unknown discrete‐time (DT) systems to achieve performance optimization in the presence of disturbances. Different from traditional model‐based and data‐driven state feedback control methods, the developed off‐policy Q‐learning algorithm updates the state feedback controller parameters and the compensator parameters by actively interacting with the unknown environment, thus the approximately optimal tracking can be realized using only data. First, an optimal tracking problem for a linear DT system with disturbance is formulated. Then, the design for controller is achieved by solving a zero‐sum game problem, leading to an off‐policy disturbance compensation Q‐learning algorithm with only a critic structure, which uses data to update disturbance compensation controller gains, without the knowledge of system dynamics. Finally, the effectiveness of the proposed method is verified by simulations.

Upfront stereotactic radiosurgery versus adjuvant radiosurgery for parasagittal and parafalcine meningiomas: a systematic review and meta-analysis.

Parafalcine and parasagittal (PFPS) are common locations for meningiomas. Surgical resection for these tumors, the first-line treatment, poses challenges due to their proximity to critical structures. This systematic review investigates the use of stereotactic radiosurgery (SRS) as a treatment for PFPS meningiomas, aiming to elucidate its safety and efficacy. The review adhered to PRISMA guidelines. Searches were conducted on MEDLINE, Embase, and Cochrane. Inclusion criteria involved studies on SRS for PFPS meningiomas, reporting procedure outcomes and complications. Tumors were presumed or confirmed to be WHO grade 1. Data was systematically extracted. Meta-analysis was performed where applicable. The review included data from eight studies, 821 patients with 878 lesions. Tumor control was achieved in greater than 80% of cases. Adverse radiation effects were reported in 7.3% of them. Recurrence and further surgical approach were observed in 17.1% and 9.2% of cases, respectively. Symptom improvement was noted in 33.2% of patients. Edema occurred in approximately 25.1% of patients. A subgroup of 283 patients had upfront SRS, achieving tumor control in approximately 97% of such cases. SRS is a safe and effective treatment for PFPS meningiomas, both as an adjuvant therapy and as an upfront treatment for often smaller tumors. Post-SRS edema can typically be managed medically and usually does not require further surgical intervention. Further studies should provide more specific data on PFPS meningiomas. The use of single and hypofractionated SRS for larger volume PFPS meningiomas should be more explored to better define the risks and benefits.

A fast simulation method for thermal management in wire arc additive manufacturing repair of a thin-walled structure

Ensuring first-time-right on-site repair of critical structures is a key challenge for additive manufacturing (AM)–based repair solutions. Fast thermal simulations are thus needed to plan efficient and error-free AM processes. This paper addresses a fast thermal simulation method for a novel subsea wire arc additive manufacturing (SWAAM) repair procedure. Current commercial finite element (FE) codes for typical welding and AM are computationally expensive and slow. The presented 2D finite difference approach can be used to simulate SWAAM on a damaged plate with around 70 times acceleration compared to real welding times, without the use of parallelization. Although not being able to accurately represent the temperature in close vicinity of the welding torch, the approach shows excellent correspondence with FE simulations and experiments in regions of the plate where the temperature has assumed a distribution that is largely two-dimensional. Compared with FE simulations, the approach is experimentally verified to be accurate to 10 °C within 7 s after the welding torch has passed a point on the plate. Thus, the approach can provide a measure of the global temperature field in a thin-walled structure during repair. The thermal simulation is preceded by a welding path planner, which generates appropriate paths based on slicing of a 3D surface scan of the damage that is to be repaired. Damages to equipment or non-ideal welding conditions are prevented by automatically pausing the welding if the calculated temperature in the path ahead of the welding torch exceeds a predefined interpass temperature limit.

Feasibility of stereotactic optical navigation for needle positioning in percutaneous nephrolithotomy

BackgroundThis study assessed the feasibility of acquiring single-attempt access to the pelvicalyceal system during percutaneous nephrolithotomy (PCNL) using stereotactic optical navigation combined with cone-beam CT (CBCT) imaging.MethodsPatients with a PCNL indication were prospectively included in this IRB approved study. After sterile preparation, fiducial markers were attached to patients’ skin. An initial intraprocedural CBCT scan was acquired, on which the urologist planned the needle trajectory using the navigation software. After verifying that no critical structures were crossed, the needle guide was aligned with the plan. A needle was manually inserted through the needle guide to the indicated depth and a second CBCT scan was performed for needle position confirmation. Both, scanning and needle insertion, were performed under apnea. The study evaluated technical success, accuracy, procedure time, complication rate, and radiation dose.ResultsBetween June 2022 and April 2023, seven patients were included. In all patients, the navigation system allowed safe puncture. However, the technical success rate was only 29%. In 42% of the cases, pelvicalyceal access was achieved by a small manual adjustment. In the remaining 29%, the needle was retracted and positioned per clinical standard. The average deviation between the needle and target was 5.9 ± 2.3 mm. The average total procedure time was 211 ± 44 min. The average radiation exposure was 6.4 mSv, with CBCT scanning contributing to 82% of this exposure.ConclusionsThe optical navigation system facilitated safe needle insertion but did not consistently ensure accurate one-attempt needle positioning for PCNL. Real-time visualization and trajectory correction may improve the technical success rate.

Improving Intrusion Detection using Satin Bowerbird Optimization with Deep Learning Model for IIoT Environment

Intrusion Detection in the Industrial Internet of Things (IIoT) concentrations on the security and safety of critical structures and industrial developments. IIoT extends IoT principles to industrial environments, but linked sensors and devices can be deployed for monitoring, automation, and control of manufacturing, energy, and other critical systems. Intrusion detection systems (IDS) in IoT drive to monitor network traffic, device behavior, and system anomalies for detecting and responding to security breaches. These IDS solutions exploit a range of systems comprising signature-based detection, anomaly detection, machine learning (ML), and behavioral analysis, for identifying suspicious actions like device tampering, unauthorized access, data exfiltration, and denial-of-service (DoS) attacks. This study presents an Improving Intrusion Detection using Satin Bowerbird Optimization with Deep Learning (IID-SBODL) model for IIoT Environment. The IID-SBODL technique initially preprocesses the input data for compatibility. Next, the IID-SBODL technique applies Echo State Network (ESN) model for effectual recognition and classification of the intrusions. Finally, the SBO algorithm optimizes the configuration of the ESN, boosting its capability for precise identification of anomalies and significant security breaches within IIoT networks. By widespread simulation evaluation, the experimental results pointed out that the IID-SBODL technique reaches maximum detection rate and improves the security of the IIoT environment. Through comprehensive experimentation on both UNSW-NB15 and UCI SECOM datasets, the model exhibited exceptional performance, achieving an average accuracy of 99.55% and 98.87%, precision of 98.90% and 98.93%, recall of 98.87% and 98.80%, and F-score of 98.88% and 98.87% for the respective datasets. The IID-SBODL model contributes to the development of robust intrusion detection mechanisms for safeguarding critical industrial processes in the era of interconnected and smart IIoT environments.