3D Model Research Articles

Multiscale X-ray phase-contrast CT uncovers adaptive changes and compensatory mechanisms of circulatory pathways during acute liver injury

Intrahepatic circulation is essential for the repair of acute liver injury (ALI); however, very limited information is available concerning changes in the circulatory pathways during ALI. Therefore, multi-scale X-ray phase-contrast CT combined with three-dimensional (3D) visualization is used to quantitatively analyze the intrahepatic circulation pathway (including the hepatic vein, portal vein and hepatic sinusoid) in the mouse model via the intraperitoneal injection of carbon tetrachloride (CCl4) from acute injury to recovery. The results demonstrate that the liver still preserves some vessel-like channels accessed to the central vein when the injury causes the severe collapse of the hepatic sinusoids that cannot be observed in two-dimensional pathologic slices. Moreover, angiogenesis is observed in the terminal branches of the hepatic vein and portal vein. Additionally, we extend the two-dimensional primary lobule to a 3D model and find that the sinusoids in zone III have the most severe injury. The sinusoids in different zones also show changes in parameters such as density and mean diameter during the ALI. In conclusion, phase-contrast CT can reveal the intact vascular system within the liver lobes, thus providing critical information for studying the mechanisms involved in the evolution of circulatory structures from damage to repair.

The Use of 3D Model Printing for Acute Planning in Oral and Maxillofacial Traumatology

Introduction Due to the complex anatomy of craniomaxillofacial structures, facial reconstruction following high-impact traumas is extremely challenging. Therefore, this study aimed to evaluate the use of biomodels in the surgical planning of complex fractures and the sequelae in the oromaxillofacial region. Materials and Methods This is a cross-sectional, exploratory, descriptive, and quantitative documentary study. It was conducted at the “Dom Luiz Gonzaga Fernandes” Emergency and Trauma Hospital, in the hinterland of the state of Paraíba, in Brazil, based on cases recorded between November 2021 and November 2022. The research instrument utilized was a self-developed questionnaire. Results No statistically significant correlation was observed between the biomodel acquisition time and the length of hospitalization, with a Spearman's correlation coefficient of r = -0.079. Although the need for adjustment of osteosynthesis material was 50% in cases where acrylonitrile butadiene styrene (ABS) models were used, with p (1) = 0.464, in order to be significantly more faithful, it would require a study with a higher sample size. The average length of surgery, in minutes, was 91.25 ± 28.00. The average cost of the materials used to manufacture the biomodels, in Brazilian reais (R$), was R$122.00 ± R$89.09. Conclusion The use of biomodels in the surgical planning of complex fractures and oromaxillofacial sequelae did not increase the length of hospitalization. The material used for the prototype manufacture suggests a potential influence on its faithfulness. The length of surgery was shorter in interventions that utilized biomodels in the planning phase. It was also noted that the average cost of manufacture varies according to the type of material chosen and the quantity required.

Full-Thickness Perfused Skin-on-a-Chip with In Vivo-Like Drug Response for Drug and Cosmetics Testing

In this study, we present a novel 3D perfused skin-on-a-chip model fabricated using micro-precision 3D printing, which offers a streamlined and reproducible approach for incorporating perfusion. Perfused skin models are well-regarded for their advantages, such as improved nutrient supply, enhanced barrier function, and prolonged tissue viability. However, current models often require complex setups, such as self-assembled endothelial cells or sacrificial rods, which are prone to variability and time-consuming. Our model uses projection micro-stereolithography 3D printing to create precise microcapillary-like channels using a biocompatible resin, overcoming the drug-absorbing properties of PDMS. A customized chip holder allows for the simultaneous culture of six perfused chips, enabling high-throughput testing. The engineered skin-on-a-chip features distinct dermis and epidermis layers, confirmed via H&E staining and immunostaining. To evaluate drug screening capabilities, inflammation was induced using TNF-α and treated with dexamethasone, with cytokine levels compared to 2D cultures and human skin biopsies. Our 3D model exhibited drug response trends similar to human skin, while showing reduced cytotoxicity over time compared to biopsies. This perfused skin-on-a-chip provides a reliable, physiologically relevant alternative for drug and cosmetics screening, simplifying perfusion setup while preserving key benefits.

Does Hand-Predominance Have a Predominant Influence on Craniofacial Asymmetric and Anthropometric Analysis in Preadolescences?

Background: Although the human body generally exhibits bilateral symmetry, achieving perfect symmetry is exceedingly uncommon. During preadolescent development, a face that approximates symmetry is considered both aesthetically and functionally ideal. This study aimed to investigate the relationship between craniofacial traits and hand predominance, using three-dimensional (3D) stereophotogrammetry to discern whether facial soft-tissue characteristics are correlated with hand preference. Materials and Methods: The study involved children aged 9 and 10 years who were free from any diagnosed craniofacial anomalies. Three-dimensional stereophotogrammetry was conducted to analyze their facial morphology, and 37 distinct anatomical landmarks were manually identified using a MATLAB-developed program. Results: A total of 188 Taiwanese children participated in the study. All participants were healthy, with a mean age of 9.79 years. Among them, 93.1% (175) were right-hand predominant, and 6.9% (13) were left-hand predominant. There were no significant differences in linear parameters or facial asymmetry between right-hand-predominant and left-hand-predominant participants (p > 0.05). However, a consistent trend toward right laterality, especially in the right lateral frontal region of the cranium, was observed, as illustrated by heat maps of the average three-dimensional model. Conclusions: The study found no association between facial morphology and hand predominance. A normal asymmetry with a rightward tendency was noted in children aged 9 to 10 years, which was particularly notable in the lateral frontal region of the head.

Experimental method for internal deformation measurement of 3D solids with embedded cracks based on 3D printing and digital speckle techniques

Quantification of the internal deformation of fractured solids such as rock masses under external loads, especially the deformation around internal fractures, is crucial for understanding and predicting the failure of fractured solids. However, it is very difficult to achieve the goal using conventional experimental methods. In this study, we proposed a novel internal deformation measurement method based on three-dimensional (3D) printing and digital speckle techniques. The 3D printing technology was applied to fabricate a 3D transparent model with an embedded elliptical crack and to set a speckle pattern on the internal section of the transparent model. The digital image correlation (DIC) method was used to determine the internal deformation field of the 3D fractured model. The measured displacements and strains of the internal sections in the fractured model were compared with the numerical simulation results. The comparison indicates that the proposed experimental method can well determine the deformation inside the 3D model. This built-in speckle method can realize real-time observation of the internal deformation of a 3D solid model in a non-contact and non-destructive manner.

Improving Real-Scene 3D Model Quality of Unmanned Aerial Vehicle Oblique-Photogrammetry with a Ground Camera

In UAV (unmanned aerial vehicle) oblique photogrammetry, the occlusion of ground objects, particularly at their base, often results in low-quality real-scene 3D models. To address this issue, we propose a method to enhance model quality by integrating ground-based camera images. This innovative image acquisition method allows the rephotographing of areas in the 3D model that exhibit poor quality. Three critical parameters for reshooting are the reshooting distance and the front- and side-overlap ratios of reshooting images. The proposed method for improving 3D model quality focuses on point accuracy, dimensional accuracy, texture details, and the triangular mesh structure. Validated by a case study involving a complex building, this method demonstrates that integrating ground camera photos significantly improves the overall quality of the 3D model. The findings show that optimal settings for reshooting include a distance (in meter units) of 1.5–1.6 times the camera’s focal length (in millimeter units), a front overlap ratio of 30%, and a side overlap ratio of 20%. Furthermore, we conclude that an overlap rate of 20–30% in reshooting is a usable value.

Magnetotelluric evidence for the deep causes of different eruptive styles of Changbaishan Tianchi and Longgang volcanoes

Longgang Volcano (LGV) and Changbaishan Tianchi Volcano (CTV) share a common magmatic source at mantle depths. However, the two volcanoes have produced completely different types of eruptions. By performing 3D inversion of an MT dataset that completely covers the LGV and CTV, we have obtained high-resolution electrical resistivity images. The results reveal that the two volcanoes have distinct magmatic plumbing systems, and this is likely the reason for their different eruptive styles. Results from 3D modeling do not show a magma chamber in the shallow crust beneath LGV, interpreted as the rapid rise of the magma from the mantle is responsible for producing a series of densely distributed volcanic cones in the LGV field. In contrast, there is a magma chamber in the upper crust beneath the CTV, where the fractional crystallization and mixing of magma has occurred. This magma chamber has facilitated multiple centralized eruptions, and thereby has led to the formation of the large CTV volcanic cone. These results indicate that differences in their crustal structures may have controlled the different eruptive activities of the LGV and CTV in CVS, Northeast China.

Continuous Viscoelasticity Measurement of Cell Spheroids via Microfluidic Electrical Aspiration.

Measurement of viscoelastic characteristics of cells cultured in three-dimensional (3D) is critical to study many biological processes including tissue and organ growth. In this article, we present a unique electrical aspiration method to measure the viscoelastic properties of cell spheroids. A microfluidic sensor was created to demonstrate this method. Unlike the traditional optical aspiration method, the aspiration of the cell spheroids is monitored via monitoring the dynamic electrical resistance change of a symmetrical microfluidic aspiration channel. We first used the microfluidic device to measure the viscoelastic properties of two types of biological tissues derived from calfskin and porcine left ventricular myocardium. The equilibrium elastic modulus and creep time constants were measured to be 148.1 ± 24.1 kPa and 76.7 ± 3.5 s and 64.5 ± 7.7 kPa and 31.4 ± 2.7 s respectively, which matched well with reported data. The test validated the principle of the electrical aspiration method. Next, we applied the method for measuring cell spheroids made of human mesenchymal stem cells at different culture stages. The equilibrium elastic modulus and apparent viscosity decreased with increasing culture time. Compared to optical aspiration methods, this microfluidic electrical aspiration method has no reliance on transparent materials and image processing, which thus allows simple setup, fast data acquisition and analysis. The use of a symmetric aspiration channel and the linear half-space model enable measurements of a large number of viscoelastic properties via a single measurement with higher accuracy. This method will enable high throughput, continuous viscoelastic measurement of cell spheroids as well as other 3D cell culture models in flow conditions without the need for any optical measurements.

Delivery of IL2RG mRNA via nanoparticles to enhance CD8+ T cell promotes anti-tumor effects against late-stage triple-negative breast cancer

BackgroundThe manipulation of CD8+ T cell functions through genetic modifications presents a novel approach to cancer immunotherapy. This study aimed to explore the effects of IL2RG-overexpressing CD8+ T cells and assess the efficacy of delivering IL2RG mRNA via nanoparticles (NPs) to the tumor microenvironment in triple-negative breast cancer (TNBC).MethodsSingle-cell RNA sequencing (scRNA-seq) was conducted on tissue from early and late-stage TNBC, followed by a meta-analysis of six breast cancer arrays from the GEO database to identify candidate genes. CRISPR/Cas9 was employed for gene knockout and overexpression in CD8+ T cells, which were then analyzed using flow cytometry, ELISA, immunofluorescence, and metabolic assays. A 3D cancer cell spheroid model was used for co-culture experiments. Lipid-coated calcium-phosphate (LCP)@IL2RG NPs were synthesized and injected into TNBC mouse models.ResultsIL2RG was identified as significantly associated with late-stage TNBC. Overexpression of IL2RG in CD8+ T cells led to increased cell activation, cytotoxicity, and glycolysis, while knockout reduced these effects. Overexpressing IL2RG in CD8+ T cells co-cultured with 3D cancer spheroids resulted in enhanced apoptosis and reduced cancer cell invasion. Injection of LCP@IL2RG NPs into TNBC mouse models significantly mitigated tumor growth.ConclusionsOverexpressing IL2RG in CD8+ T cells enhances tumor immunotherapy. Delivering IL2RG mRNA via NPs further amplifies this effect, offering a promising strategy for the treatment of late-stage TNBC.

Detection of brain tumor using Hybridized 3D U-Net model on MRI images

Detection of brain tumor using Hybridized 3D U-Net model on MRI images

Automated volumetric analysis of the inner ear fluid space from hydrops magnetic resonance imaging using 3D neural networks

Due to the development of magnetic resonance (MR) imaging processing technology, image-based identification of endolymphatic hydrops (EH) has played an important role in understanding inner ear illnesses, such as Meniere’s disease or fluctuating sensorineural hearing loss. We segmented the inner ear, consisting of the cochlea, vestibule, and semicircular canals, using a 3D-based deep neural network model for accurate and automated EH volume ratio calculations. We built a dataset of MR cisternography (MRC) and HYDROPS-Mi2 stacks labeled with the segmentation of the perilymph fluid space and endolymph fluid space of the inner ear to devise a 3D segmentation deep neural network model. End-to-end learning was used to segment the perilymph fluid and the endolymph fluid spaces simultaneously using aligned pair data of the MRC and HYDROPS-Mi2 stacks. Consequently, the segmentation performance of the total fluid space and endolymph fluid space had Dice similarity coefficients of 0.9574 and 0.9186, respectively. In addition, the EH volume ratio calculated by experienced otologists and the EH volume ratio value predicted by the proposed deep learning model showed high agreement according to the interclass correlation coefficient (ICC) and Bland–Altman plot analysis.

Integrating 3D technology with the Sampaio classification for enhanced percutaneous nephrolithotomy in complex renal calculi treatment

BackgroundTo investigate the safety and efficacy of percutaneous nephrolithotomy (PCNL) in the treatment of complicated renal calculi by integrating three-dimensional (3D) computed tomography (CT) reconstruction with the Sampaio classification of the renal collecting system.MethodsSixty-four consecutive patients with complex kidney calculi who underwent PCNL between January 2019 and October 2023 were retrospectively analyzed and divided into experimental group (3D printing) and control group (CT imaging) according to their willingness to pay for 3D imaging. Both groups underwent preoperative CT urography. The Digital Imaging and Communications (DICOM) in Medicine data of the experimental group from CT imaging were used for 3D reconstruction and model printing. Then, the Sampaio classification system was used to design the puncture channel and develop a surgical strategy.ResultsThe 3D-printed models of the experimental group successfully displayed the Sampaio classification system. There was no significant difference in the baseline parameters between the groups. Compared with the control group, the experimental group exhibited significant improvements in the puncture time, number of puncture needles, number of puncture channels, target calyx consistency, number of first puncture channels, and stone clearance. There were no significant differences in the total operative time, decrease in the hemoglobin level, length of hospital stay, and postoperative complications between the groups.ConclusionsIntegration of 3D technology with the Sampaio classification of the renal collecting system can enhance the preoperative evaluation and planning of percutaneous renal access. This approach allows a more precise method of PCNL for treating complex renal calculi.

Impact of mutation type on ectopic ossification among adult patients with X-linked hypophosphatemia

Abstract Context Causative factors for ectopic ossifications in X-linked hypophosphatemia (XLH) remain to be elucidated. Objective To investigate the genotype-phenotype correlations between PHEX and ectopic ossifications in XLH. Methods Biochemical data, spinal computed tomography scans, and X-rays of hip/knee joints were retrospectively reviewed. Genetic analysis and the measurement of plasma inorganic pyrophosphate (PPi) - a potent inhibitor of tissue calcification - were performed. The effect of PHEX mutations on protein function was predicted using nonsense-mediated decay (NMD) and 3D structure modeling. The index of ossification of the anterior/posterior longitudinal ligament and yellow ligament (OA/OP/OY index) and the sum of the OA/OP/OY index (OS index) were used to quantify the severity of spinal ligament ossification. The severity of the hip/knee osteoarthritis was evaluated by the Kellgren-Lawrence classification. Results We examined 24 distinct pathogenic PHEX variants in 28 patients from a study population of 33 individuals in 27 unrelated, non-consanguineous families. Among the 31 patients whose plasma samples were analyzed for PPi, 14 patients (45%) showed decreased plasma PPi concentrations, however, PPi concentrations did not correlate with mutation type or ectopic ossification. Fibroblast growth factor 23 levels in females with NMD-insensitive mutations trended lower than in males with NMD-sensitive mutations but failed to reach statistical significance. Both models revealed no correlations between PHEX pathogenic variant and ectopic ossification. Conclusion Neither modeling found correlates between PHEX pathogenic variants and ectopic ossificatio. The effects of PPi on ectopic ossifications in adults with XLH revealed trends that should be investigated with a large sample size.

Home-based guidance training system with interactive visual feedback using kinect on stroke survivors with moderate to severe motor impairment

The home-based training approach benefits stroke survivors by providing them with an increased amount of training time and greater feasibility in terms of their training schedule, particularly for those with severe motor impairment. Computer-guided training systems provide visual feedback with correct movement patterns during home-based training. This study aimed to investigate the improvement in motor performance among stroke survivors with moderate to severe motor impairment after 800 min of training using a home-based guidance training system with interactive visual feedback. Twelve patients with moderate to severe stroke underwent home-based training, totaling 800 min (20–40 min per session, with a frequency of 3 sessions per week). The home-based guidance training system uses Kinect to reconstruct the 3D human body skeletal model and provides real-time motor feedback during training. The training exercises consisted of six core exercises and eleven optional exercises, including joint exercises, balance control, and coordination. Pre-training and post-training assessments were conducted using the Fugl-Meyer Assessment-Upper Limb (FMA-UE), Fugl-Meyer Assessment-Lower Limb (FMA-LE), Functional Ambulation Categories (FAC), Berg Balance Scale (BBS), Barthel Index (BI), Modified Ashworth Scale (MAS), as well as kinematic data of joint angles and center of mass (COM). The results indicated that motor training led to the attainment of the upper limit of functional range of motion (FROM) in hip abduction, shoulder flexion, and shoulder abduction. However, there was no improvement in the active range of motion (AROM) in the upper extremity (U/E) and lower extremity (L/E) joints, reaching the level of the older healthy population. Significant improvements were observed in both left/right and superior/inferior displacements, as well as body sway in the mediolateral axis of the COM, after 800 min of training. In conclusion, the home-based guidance system using Kinect aids in improving joint kinematics performance at the level of FROM and balance control, accompanied by increased mediolateral body sway of the COM for stroke survivors with moderate to severe stroke. Additionally, spasticity was reduced in both the upper and lower extremities after 800 min of home-based training.

ReMiND: Recovery of missing neuroimaging using diffusion models with application to Alzheimer’s disease

Abstract Missing data is a significant challenge in medical research. In longitudinal studies of Alzheimer’s disease (AD) where structural magnetic resonance imaging (MRI) is collected from individuals at multiple time points, participants may miss a study visit or drop out. Additionally, technical issues such as participant motion in the scanner may result in unusable imaging data at designated visits. Such missing data may hinder the development of high-quality imaging-based biomarkers. To address the problem of missing MRI data in studies of AD, we introduced a novel 3D diffusion model specifically designed for imputing missing structural MRI (Recovery of Missing Neuroimaging using Diffusion models (ReMiND)). The model generates a whole-brain image conditional on a single structural MRI observed at a past visit or conditional on one past and one future observed structural MRI relative to the missing observation. The performance of models was compared with two alternative imputation approaches: forward filling and image generation using variational autoencoders. Experimental results show that our method can generate 3D structural MRI with high similarity to ground-truth images at designated visits. Furthermore, images generated using ReMiND show relatively lower differences in volume estimation between the imputed and observed images compared to images generated by forward filling or autoencoders. Additionally, ReMiND provides more accurate estimated rates of atrophy over time in important anatomical brain regions than the two comparator methods. Our 3D diffusion model can impute missing structural MRI data at a single designated visit and outperforms alternative methods for imputing whole-brain images that are missing from longitudinal trajectories.

Quantum leap: observing antiferromagnetic transition in a 3D fermionic Hubbard model with ultracold atoms

Quantum leap: observing antiferromagnetic transition in a 3D fermionic Hubbard model with ultracold atoms

Three-dimensional finite element analysis of biological signal feedback in the mechanical properties of sound production

In response to the problems of low reliability and long time consumption in traditional research on sound production, this article used electromyography (EMG) signals as input signals to build a high-precision sound production mechanics model. A Proportional-Integral-Derivative (PID) controller was used to dynamically adjust the model and develop a real-time feedback system. This article established a detailed three-dimensional (3D) finite element model including the vocal cords and throat, defined the nonlinear elastic properties and linear elastic properties of different tissues, and used tetrahedral grid partitioning technology to improve the computational accuracy of the model. Through a EMG sensor, an individual EMG was collected and filtered to remove noise. The processed EMGs were used as input parameters for the finite element model to drive the muscle units in the model. By using a PID controller to receive real-time EMG input, the error was calculated and the model was adjusted, enabling accurate simulation of the mechanical properties of vocal cord vibration under different vocal states and achieving real-time feedback. Considering the complexity of vocal cord vibration driven by biological signals, this article simulated and analyzed the modal characteristics of vocal cord vibration, and analyzed the differences in vocal cord vibration characteristics under different vocal states. The sound pressure distribution and resonance frequency were simulated and analyzed to understand the propagation characteristics of sound. Finally, by comparing and analyzing the simulated data with the actual collected data, it was found that the maximum relative error rate of the model under different sound states was 6.14%, and the overall error rate of the model was relatively low, which verified the reliability of the model. The findings demonstrated that the feedback delays of the model in different sound states were all within 100 milliseconds, indicating that the system had high real-time performance and accuracy, which was promising in practical applications.

SLC37A4, gene responsible for glycogen storage disease type 1b, regulates gingival epithelial barrier function via JAM1 expression

Solute carrier family 37 member 4 (SLC37A4) is known to regulate glucose-6-phosphate transport from cytoplasm to the lumen of the endoplasmic reticulum, which serves to maintain glucose homeostasis. Glycogen storage disease type 1b (GSD1b) is caused by a mutation of SLC37A4, leading to a glycogenolysis defect. Although GSD1b cases are known to be complicated by periodontitis, the etiological molecular basis remains unclear. The present study investigated the effects of SLC37A4 on gingival barrier function. Examinations of immortalized human gingival epithelial (IHGE) cells showed SLC37A4 localized in the endoplasmic reticulum. SLC37A4 knockout decreased expression of JAM1, a tight junction-related protein, in IHGE cells. Using in silico analysis to investigate potential transcription factor binding sites, H6 family homeobox 3 (HMX3) was shown to be related to JAM1 expression. In HMX3-knockdown IHGE cells, JAM1 expression was markedly suppressed. Furthermore, HMX3 was scarcely detected in SLC37A4-knockout cells, while HMX3 overexpression restored JAM1 expression in those cells. Finally, using a three-dimensional multilayered gingival epithelial tissue model, knockout of SLC37A4 was also found to increase permeability to lipopolysaccharide and peptidoglycan, which was dependent on JAM1 expression. Specific downregulation of HMX3 by SLC37A4 and the consequent decrease in JAM1 expression provides findings indicating a molecular basis for the reduction in barrier function of gingival epithelial tissues in GSD1b cases.

Investigation on metal vapor characteristics and keyhole/melt pool dynamics in high-power laser welding with side gas flow

High-power laser welding processes involve intense interactions between the laser beam and the base material, resulting in severe welding defects such as humping, spattering, and undercutting. Utilizing side gas flow may provide an effective approach for minimizing these defects. However, the effects of side gas flow on the dynamic behavior and weld formation necessitate further investigation. In this study, an innovative analysis of metal vapor characteristics and keyhole/melt pool dynamics in high-power laser welding with side gas flow is presented, combining experimental and simulation results. A three-dimensional transient fluid flow model was developed, uniquely integrating an adaptive heat source, evaporation-condensation processes, and metal vapor energy attenuation to provide a novel perspective on the effects of side gas flow in high-power laser welding. The results display that side gas flow could suppress plasma, increase thermal input to the melt pool, and intensify the flow of liquid metal toward the pool bottom during high power laser welding, thereby enhancing weld seam penetration. The numerical results indicate that variations in flow rate significantly impact metal vapor morphology, with higher flow rates reducing both the average area and height of the metal vapor and effectively suppressing the size of metal vapor/plasma. When the side gas flow rate is 20 l/min, with the gas flow impact point located at the keyhole opening and the nozzle height set to 3 mm, the side gas flow significantly enhances the depth-to-width ratio of the weld seam in 316L stainless steel laser welding. This work can provide guidance for suppression of weld defects in high-power laser welding of medium-thick steel components, which has important theoretical significance and application value.

Modelling of cracking during beam oscillation laser welding of a creep-resistant nickel alloy

During high power laser welding of Inconel 740H, horizontal solidification cracks form at locations between approximately 70–80% of the weld depth. With the integration of circular beam oscillation, the laser energy density distribution and underlying thermo-mechanical conditions were altered. By coupling three-dimensional heat transfer, fluid flow, and stress modelling tools, the role that circular beam oscillation plays in the formation of the strain rates and stresses driving this cracking phenomenon was identified. While the addition of a circular oscillation pattern appeared to lower the stress levels along the solidification front, it did not eliminate the appearance of horizontal cracking. Only when the beam amplitudes reached 1.6 mm did solidification cracking disappear, but the weld depths were also significantly reduced.