Mm In Depth Research Articles

Large Scale Ultrafast Manufacturing of Wireless Soft Bioelectronics Enabled by Autonomous Robot Arm Printing Assisted by a Computer Vision-Enabled Guidance System for Personalized Wound Healing.

A Customized wound patch for Advanced tissue Regeneration with Electric field (CARE), featuring an autonomous robot arm printing system guided by a computer vision-enabled guidance system for fast image recognition is introduced. CARE addresses the growing demand for flexible, stretchable, and wireless adhesive bioelectronics tailored for electrotherapy, which is suitable for rapid adaptation to individual patients and practical implementation in a comfortable design. The visual guidance system integrating a 6-axis robot arm enables scans from multiple angles to provide a 3D map of complex and curved wounds. The size of electrodes and the geometries of power-receiving coil are essential components of the CARE and are determined by a MATLAB simulation, ensuring efficient wireless power transfer. Three heterogeneous inks possessing different rheological behaviors can be extruded and printed sequentially on the flexible substrates, supporting fast manufacturing of large customized bioelectronic patches. CARE can stimulate wounds up to 10 mm in depth with an electric field strength of 88.8 mVmm-1. In vitro studies reveal the ability to accelerate cell migration by a factor of 1.6 and 1.9 for human dermal fibroblasts and human umbilical vein endothelial cells, respectively. This study highlights the potential of CARE as a clinical wound therapy method to accelerate healing.

Abstract 4135872: Effects of In-vivo Contact Force on Pulsed Field Ablation Lesion Size in Porcine Ventricles

Background: Pulsed field ablation (PFA) is an innovative modality for treating arrhythmias that is mostly non-thermal and renders myocardial tissue non-viable by creating pores in cardiac cell membranes. The impact of contact force (CF) on PFA efficacy is not well characterized. Hypothesis: We hypothesize that, while contact is necessary for PFA, increasing CF will not have a significant effect on in vivo ablation lesion size. Aim: We seek to investigate the effects of CF on acute PFA lesions in a beating porcine heart model. Methods: The ventricles of 7 porcine animals were ablated in vivo with PFA (500V, at 20μs for 50 pulses separated by 200ms) using a focal bipolar irrigated ablation catheter and BTX 830 electroporation generator (Harvard Apparatus). CF was measured before and after each PFA application using CARTO 3. Lesions were divided into standard CF (5-15g), high CF (16-30g), and very high CF (>31g). Results: A total of 46 lesions were analyzed. Gross pathology showed no significant difference in maximum width, lesion depth, and lesion volume between the three groups ( Figure 1A-B ). Linear regression showed a decrease of 0.003 mm in depth (depth = -0.003 × CF + 1.8, R = 0.05), an increase of 0.01 mm in width (width = 0.01 × CF + 5.7, R = 0.09), and a decrease of 0.05 mm 3 in volume (volume = -0.05 × CF + 26.8, R = 0.03) for each additional gram of CF ( Figure 1C ). Conclusion: While contact is necessary, increasing CF did not have a significant effect on in-vivo PFA lesion dimensions in a beating porcine heart model.

Letter to the Editor.

The authors wish to acknowledge that the information on the Monet website⁹ has now changed (2024) to reflect that exposures longer than 3 seconds are required for larger restorations and that overlapping exposures should be used. The website now states that for preparation areas that are larger than 5mm in depth and 8mm in diameter, two overlapping spot cures of 3 seconds are recommended (Figure 2). The single 1 and 3x1- second exposure times used in the article are not recommended by the manufacturer and should now be considered 'off-label' use of the Monet.

Three-Dimensional Volume Ultrasound Assessment of Cesarean Scar Niche and Cervix in Pregnant Women: A Reproducibility Study.

To assess the reproducibility of standardized 3-dimensional (3D) ultrasound volume analysis of the dimensions and the position of cesarean birth (CB) scar niche relative to the cervix in pregnant women. This prospective single-center study in women with 1 previous CB ≥8 cm cervical dilatation acquired ultrasound volumes between 11 and 24 weeks' gestation in a mid-sagittal plane. Two experienced operators processed the volumes using virtual organ computer-aided analysis. A CB scar niche was defined as an indentation at the scar site of ≥2 mm in depth. Niche and cervix volumes were calculated using manual contouring. Agreement for categorical variables was expressed using intraclass correlation coefficient (ICC). The Bland-Altman method was used to assess numerical variable reproducibility. To achieve the desired statistical power, 52 participants were included. The intraobserver agreement on niche classification relative to the internal os was 100%, with an interobserver kappa coefficient of 0.98 (95% confidence interval [CI] 0.97-0.99, P < .05). The intraobserver ICC for niche volume was 0.94 (95% CI 0.90-0.96; P < .001), with a mean difference of -15.32 mm3 (±109.32). The interobserver ICC was 0.78 (95% CI 0.62-0.87; P < .001), with a mean difference of -21.57 mm3 (±202.01). The ICC for niche/cervix volume ratio were 0.94 (95% CI 0.90-0.96; P < .001) and 0.79 (95% CI 0.63-0.87; P < .001) for intra- and interobserver reproducibility, respectively. This study demonstrates that 3D CB scar sonographic features are highly reproducible in pregnant women with a history of advanced labor CB. The validated protocol can guide future research on the association with subsequent adverse pregnancy outcomes.

Comparison of gauze packing, sponge-based, and hemostatic Surgicel wound stasis dressings to treat hemorrhages from grade IV liver injuries: An experimental study

BackgroundUncontrolled bleeding is still the major factor leading to preventable deaths following trauma. This study sought to assess the effectiveness of mini sponge-based wound stasis, cellulose-based local hemostatic, and traditional gauze dressings for the control of hemorrhages resulting from grade 4 liver injuries in rats. MethodsThirty Sprague-Dawley rats were divided into three equal groups. In the first group, a liver laceration was treated with gauze packing. The second group received XStat minisponge dressing (MDS), and the third group was administered a combination of MDS dressing and Surgicel hemostatic agent. After gaining access to the intra-abdominal cavity, a liver laceration measuring 10 mm in length, 5 mm in depth, and extending to the middle lobe was created. The dressings were removed after 2 and 10 minutes to assess the amount of bleeding, and any bleeding was documented again after 48 hours. Intraperitoneal adhesions were evaluated during euthanasia. ResultsAt 2 minutes post-injury, the gauze packing group had an average bleeding volume of 0.97±0.15 mL, compared to 1.08±0.25 mL in the MDS group (P=0.26) and 1.02±0.18 mL in the MDS+Surgicel group (P=0.69). At 10 minutes, the bleeding volumes were 0.13±0.05 mL, 0.22±0.01 mL (P=0.09), and 0.14±0.05 mL (P=0.19), respectively. At 48 hours, significant differences were observed in bleeding volumes (gauze: 0.55±0.18 mL, MDS: 1.15±0.21 mL, MDS+Surgicel: 0.82±0.06 mL, P<0.001). Mortality rates after 14 days were 0% in the gauze packing group, 60% in the MDS group (P=0.001), and 60% in the MDS+Surgicel group (P=0.001). The gauze packing group displayed no adhesions, while the other groups exhibited adhesions in the liver, bowel, omentum, and abdominal wall. ConclusionOur results indicate that, when it comes to managing bleeding in severe liver injuries, traditional gauze packing remains the tried-and-true method, showing superior effectiveness in terms of blood loss and mortality when compared to XStat minisponge dressings and the fibrillar Surgicel hemostatic agents.

Thermal model to investigate temperature distribution with a hollow notched K-wire for bone drilling

K-wire drilling is commonly used in orthopedic surgeries, generating significant heat that can lead to bone thermal osteonecrosis. To understand the heat propagation and thermal damage region, a mathematical model of the negative rake angle on the hollow notched K-wire was established. Subsequently, a theoretical model of the shear angle for this negative rake angle was proposed. Based on these models, a comprehensive theoretical model of the heat flux was derived. The accurate heat flux was determined using the theoretical values, and experimental temperature data through inverse heat transfer method (IHTM). This heat flux was then applied in a finite element analysis to simulate the heat transfer process and identify thermal damage regions under different drilling conditions. Results showed that the thermal damage region of bone with a solid K-wire, hollow notched K-wire without cooling, with air cooling, and with water cooling were approximately 6.4 mm, 3.2 mm, 2.6 mm, and 4.8 mm in width, respectively, and 6.79 mm, 6.45 mm, 6.39 mm, and 6.58 mm in depth, respectively. This study demonstrates that the hollow notched K-wire with air cooling is a potential solution to reduce the thermal damage region, thereby accelerating patient recovery.

Flexural Strength of Nanohybrid Composite Resin: An in-vitro Study

In the present study, the Flexural strength of nanohybrid composite was compared with conventional microfilled composite resin in vitro. Thirty nanohyrid and 30 conventional microfilled composite resins were subjected to Flexural strength measurement as follows; a teflon mold (4 mm in diameter and 6 mm in depth) was filled with materials, light cured through the glass slides for 40 sec top and bottom surfaces. Then the specimens were taken out from the mold, again light curing for 40 sec, stored in dry condition and placed into a Flexural strength tester and loaded until fracture of the sample. Student t-test was performed to assess the differences between two groups and a value of p &gt;0.05 was considered as statistically significance. The results showed that the means ± SD Flexural strength of nanobybrid and conventional microfilled composite resin were 118.70 ± 3.90 Mpa and 77.43 ± 2.65 Mpa, respectively and the differences were statistically significant. It can be concluded that nanohybrid is superior to conventional microfilled composite resin in respect to Flexural strenth in class II restorations of permanent molar teeth.

Vacuum-based and body-mounted robotic-patient interface with an integrated metasurface for MRI-guided interventions

Abstract The increased clinical relevance of image-guided procedures, particularly of interventional magnetic resonance imaging (iMRI), highlights the need for advanced devices and robotics to optimize those procedures. To enable a realistic integration of robotics into the clinical workflow, robotic-patient interfaces (RPI) are required to ensure both functionality and usability. However, current concepts have issues with patient accessibility and safety, user handling, or performing interventions on versatile body regions. This work presents a novel silicone-based RPI to flexibly mount the ’Micropositioning Robotics for Image-Guided Surgery’ (μRIGS) system on differently shaped body regions through vacuum, regulated with an electronic miniature pump. Maximum holding forces of 60N at −0.1 bar and 66N at −0.2 bar relative vacuum pressure were reached depending on the applied human body area and tensile force angles. MRI with the integrated metasurface indicated up to 200% signal enhancement, enabling improved tissue contrast within the first 20mm in depth. The multifunctional design supported the incorporation of the sterile iMRI workflow concept. This RPI enables a realistic integration of future technologies such as miniature robots, tracking markers, and instrument holders into complex interventional workflows. Further long-term studies are needed to evaluate the effects of vacuum application lasting for 1-2 hours on different skin types.

Research on jet electrochemical machining with coaxial megasonic assistance

In order to address the problem of poor localization in electrochemical machining (ECM), a coaxial megasonic assisted jet ECM method was proposed. Based on theoretical analysis, experiments were conducted to compare the effects of various electrolyte flow rates, electrolytic voltage and megasonic power levels on pit ECM. The results indicate that, in the range of experimental parameters, the increase of electrolyte flow rate and megasonic power can increase the machining depth, so as to improve the depth-diameter ratio of ECM pits. The use of coaxial megasonic-assisted jet ECM can enhance the depth-diameter ratio of etched pits compared to the without megasonic one. When applying a megasonic power of 22 W, the dimensions of the ECM pit were measured as 0.81 mm in depth and 5.73 mm in diameter, resulting in an depth-diameter ratio of 0.140. Under the same conditions, without megasonic assistance, the pit diameter is reduced to 0.65 mm while the pit depth increases to 6.36 mm, resulting in a depth-diameter ratio of 0.102. Additionally, The results also demonstrate that, the increase of electrolytic voltage makes the depth to diameter ratio of pit further increase on the original basis. With an electrolyte flow rate of 0.9 L/min and a megasonic power of 22 W, the use of electrolysis voltage of 50 V increased the depth-diameter ratio of etched pits to 0.173. Using the above preferred parameters, electrolytic milling of the wide groove is carried out. The depth-diameter ratio of the wide groove is increased from 0.039 to 0.059 by appending coaxial megasonic. This further verified the effectiveness of the coaxial megasonic-assisted jet ECM method.

Microbiological and Salivary Biomarkers Successfully Predict Site-Specific and Whole-Mouth Outcomes of Nonsurgical Periodontal Treatment.

Background/Objectives: Nonsurgical periodontal treatment (NSPT) is the gold-standard technique for treating periodontitis. However, an individual's susceptibility or the inadequate removal of subgingival biofilms could lead to unfavorable responses to NSPT. This study aimed to assess the potential of salivary and microbiological biomarkers in predicting the site-specific and whole-mouth outcomes of NSPT. Methods: A total of 68 periodontitis patients exhibiting 1111 periodontal pockets 4 to 6 mm in depth completed the active phase of periodontal treatment. Clinical periodontal parameters, saliva, and subgingival biofilm samples were collected from each patient at baseline and three months after NSPT. A quantitative PCR assay was used to detect the presence of Fusobaterium nucleatum and Porphyromonas gingivalis in the biofilm samples. Salivary biomarkers including matrix metalloproteinase (MMP)-9, glutathione S-transferase (GST), and Annexin-1 were assayed both qualitatively (Western blot analysis) and quantitively (ELISA). Results: NSPT yielded significant improvements in all clinical parameters, including a reduction in bacterial load and decreased levels of MMP-9 together with increased concentrations of GST and Annexin-1. The binary logistic regression suggested that the overall accuracy of P. gingivalis identification, probing pocket depth, and interproximal sites was 71.1% in predicting successful site-specific outcomes. The salivary biomarker model yielded an overall accuracy of 79.4% in predicting whole-mouth outcomes following NSPT. Conclusions: At baseline, the presence of shallow periodontal pockets at interdental locations with a lower abundance of P. gingivalis is predictive of a favorable response to NSPT at the site level. Decreased salivary MMP-9 associated with increased GST and Annexin-1 levels can predict successful whole-mouth outcomes following NSPT.

Effect of dispersive electrode position (anterior vs. posterior) in epicardial radiofrequency ablation of ventricular wall: A computer simulation study.

An epicardial approach is often used in radiofrequency (RF) catheter ablation to ablate ventricular tachycardia when an endocardial approach fails. Our objective was to analyze the effect of the position of the dispersive patch (DP) on lesion size using computer modeling during epicardial approach. We compared the posterior position (patient's back), commonly used in clinical practice, to the anterior position (patient's chest). The model considered ventricular wall thicknesses between 4 and 8 mm, and electrode insertion depths between .3 and .7 mm. RF pulses were simulated with 20 W of power for 30 s duration. Statistically significant differences (P < .001) were found between both DP positions in terms of baseline impedance, RF current (at 15 s) and thermal lesion size. The anterior position involved lower impedance (130.8 ± 4.7 vs. 146.2 ± 4.9 Ω) and a higher current (401.5 ± 5.6 vs. 377.5 ± 5.1 mA). The anterior position created lesion sizes larger than the posterior position: 8.9 ± 0.4 vs. 8.4 ± 0.4 mm in maximum width, 8.6 ± 0.4 vs. 8.1 ± 0.4 mm in surface width, and 4.5 ± 0.4 vs. 4.3 ± 0.4 mm in depth. Our results suggest that: (1) the redirection of the RF currents due to repositioning the PD has little impact on lesion size and only affects baseline impedance, and (2) the differences in lesion size are only 0.5 mm wider and 0.2 mm deeper for the anterior position, which does not seem to have a clinical impact in the context of VT ablation.

Multi-objective optimization of custom implant abutment design for enhanced bone remodeling in single-crown implants using 3D finite element analysis

The optimal configuration of a customized implant abutment is crucial for bone remodeling and is influenced by various design parameters. This study introduces an optimization process for designing two-piece zirconia dental implant abutments. The aim is to enhance bone remodeling, increase bone density in the peri-implant region, and reduce the risk of late implant failure. A 12-month bone remodeling algorithm subroutine in finite element analysis to optimize three parameters: implant placement depth, abutment taper degree, and gingival height of the titanium base abutment. The response surface analysis shows that implant placement depth and gingival height significantly impact bone density and uniformity. The taper degree has a smaller effect on bone remodeling. The optimization identified optimal values of 1.5 mm for depth, 35° for taper, and 0.5 mm for gingival height. The optimum model significantly increased cortical bone density from 1.2 to 1.937 g/cm3 in 2 months, while the original model reached 1.91 g/cm3 in 11 months. The standard deviation of density showed more uniform bone apposition, with the optimum model showing values 2 to 6 times lower than the original over 12 months. The cancellous bone showed a similar trend. In conclusion, the depth and taper have a significant effect on bone remodeling. This optimized model significantly improves bone density uniformity.

High-spatiotemporal resolution microwave-induced thermoacoustic tomography for imaging biological dynamics in deep tissue

Biological systems undergo constant dynamic changes across various spatial and temporal scales. To investigate the intricate biological dynamics in living organisms, there is a strong need for high-speed and high-resolution imaging capabilities with significant imaging depth. In this work, we present high-spatiotemporal resolution microwave-induced thermoacoustic tomography (HR-MTAT) as a method for imaging biological dynamics in deep tissues. HR-MTAT utilizes nanosecond pulsed microwave excitation and ultrasound detection, with appropriate spatial configurations, to achieve high coupling of the sample to the microwaves, to produce images in soft tissue with dielectric contrast and sub-millimeter spatial resolution (230 μm), to a depth of a few centimeters. Notably, by employing a 128-channel parallel signal acquisition and digitization strategy, the field programmable gate array module manages data synthesis, and GPU-based parallel pixel reconstruction facilitates HR-MTAT to accomplish single-frame image reconstruction in an impressive 50 μs. The practical feasibility of HR-MTAT was evaluated in live mice. The results show that HR-MTAT can noninvasively image whole-body small animals (up to 60 mm in depth) with clear resolution of internal organ structures at a frame rate of 100 Hz, without the need for labeling. At this high spatiotemporal resolution, HR-MTAT can capture respiration, heartbeat, and arterial pulse propagation without motion artifacts and track bio-nanoprobes in livers and tumors. These findings demonstrate HR-MTAT's ability to perform dynamic imaging with high contrast and resolution in deep tissues.

Dynamic response of armor-piercing bullets to blunt and penetration with protective gelatin

To investigate the coupled damage mechanism of blunt impact and bullets penetration after penetrating ballistic plates against human body targets, experiments were conducted using 6.8 mm caliber armor-piercing bullets against gelatin targets with protective coatings. A numerical analysis model was developed to simulate bullet penetration into gelatin with protective coatings, obtaining endpoint characteristic quantities such as bullet velocity changes, changes in energy distribution, pressure, stress, and stress wave variations within the gelatin target after protection. The results indicate that at a velocity of 640 m·s-1, the 6.8 mm caliber armor-piercing round failed to penetrate the ballistic plate yet still caused a blunt impact depression of 37 mm in depth. Under conditions where the bullet did not penetrate the ballistic plate, approximately 80% of the bullet's kinetic energy was absorbed by the ballistic plate. At a velocity of 740 m·s-1, the bullet penetrated the ballistic plate, resulting in a blunt impact depression depth of 56 mm and an instantaneous cavity with a maximum diameter of 60 mm. During the process of penetrating the ballistic plate, approximately 50% of the bullet's kinetic energy was absorbed by the ballistic plate, and about 40% of the remaining kinetic energy transferred into the gelatin during the penetration of the target.

Paper 49: Osteochondral Allograft Transplantation for Capitellar Osteochondritis Dissecans: Excellent Patient Reported Outcomes Scores and High Return to Sports

Objectives: Unstable osteochondritis dissecans of the capitellum (OCD-C) is treated surgically, most commonly with loose body removal and marrow stimulation. This treatment has historically been associated with suboptimal return to high-demand upper extremity sports (baseball and gymnastics) and persistent elbow pain. Fresh osteochondral allograft transplantation (OAlloT) is an alternative treatment which restores subchondral bone and articular cartilage without donor site morbidity associated with autograft harvest. The purpose of this study was to evaluate the outcomes of osteochondral allograft transplantation in pediatric patients with unstable OCD-C 10mm or greater in size. Methods: A single-center prospective study was performed of consecutive pediatric patients, less than 19 years of age, with unstable OCD-C 10mm or greater in size treated with primary fresh OCAlloT using pre-cut 10mm, 12mm, or 16mm cores. Imaging, including radiographs and MRI were obtained preoperatively to assess OCD size and characteristics, as well as postoperatively to assess incorporation of the OCA. Patient reported outcome scores (PROs), including sport data, were obtained preoperatively and annually following surgery. Minimum follow-up duration was 2 years. Results: 26 elbows in 24 patients, mean age 13.4 years (11.3 – 17.1 years) met inclusion. The most common primary sport was gymnastics in 11 elbows (42%), baseball/softball in 7 elbows (27%), and cheer in 3 elbow (12%). The majority of patients (88%) played at a competitive level. Median symptom duration prior to presentation was 3 months. The most common presenting symptoms were pain (85%) and mechanical symptoms (81%). Sixteen elbows (62%) presented with a &gt;5° loss of elbow extension compared to the contralateral side. The capitellar physis was open in 23 elbows (88%). OCD location was central in 17 elbows (65%) and far lateral in 9 elbow (35%). Mean MRI size of the OCD was 11 mm in coronal width, 12 mm in sagittal length, and 6 mm in depth. Twelve elbows (48%) had a loose body on MRI. The majority of elbows (22, 85%) were treated with a single allograft plug, while 4 elbows had two allograft plugs transplanted. Median OCA size was 12 mm. There were no infections nor arthrofibrosis. Two elbows (8%) had a secondary surgery, both underwent partial synovectomy and chondroplasty at 14- and 16-months following the primary surgery. Postoperative MRIs were obtained in 15 elbows (58%) and had a mean BOGIE (Boston Osteochondral Graft Incorporation in the Elbow) score of 11, thus documenting a high degree of incorporation. Mean follow-up duration was 40 months (range 25 – 60 months). All patients had preoperative, 1-year, and 2-year PROs (Table 1). 21 elbows (81%) had returned to sports at 1-year postoperatively9, and all but 1 patient had returned to sports by 2 years following surgery. Forty-five percent of gymnasts returned to gymnastics, while the remaining pursued different sports. Five of 6 baseball players (83%) returned to baseball. Conclusions: OCAlloT as a treatment for OCD-C is a procedure associated with low rates of complications, excellent graft incorporation, high elbow function and patient satisfaction, and overall high rates of return to sports at 2-years. Return to sports, particularly among gymnasts was less than 50% in this series, which we attribute to a combination of factors, including loss of training and competition time at a critical time for an elite gymnast as well as physician counseling on alternative sports with less stress on the elbow. Continued patient follow-up is ongoing and will be critical to the assessment of this treatment on the mid- and long-term outcomes in these young athletes. [Figure: see text]

Monotonic and cyclic flexural performance of timber beams strengthened with glass fiber-reinforced polymer rods using near-surface mounted technique

Wood has gained widespread use as a construction material for structures. The strengthening of timber structures using fiber-reinforced polymer (FRP) reinforcement remains challenging. This paper presents an experimental investigation of timber beams strengthened with glass FRP (GFRP) rods subjected to flexure. Sixteen specimens, including four un-strengthened beams (control beams) and twelve strengthened beams, were tested. The beam dimensions were 45 mm in width, 95 mm in depth, and 1800 mm in length. The GFRP rods were retrofitted the beam soffit applying near-surface mounted (NSM) method. The test variables included the GFRP ratios by volume (i.e., 0 %, 0.59 %, 0.88 %, and 1.32 %) and the loading types of monotonic and cyclic loading conditions. The flexural performance of the beams, including the capacity, mid-span deflection versus load, displacement at the peak load, initial stiffness, energy absorption, and failure mode are assessed. Additionally, the cross-section equilibrium analysis of the GFRP-reinforced timber beams is implemented to compare against the experimental results. The experimental results indicated that the GFRP rods can enhance the flexural effectiveness of the strengthened beams subject to both monotonic and cyclic tests. Compared with the reference beams, the GFRP-retrofitted beams showed an increase by 20 %− 61 % in load-carrying capacity, by 58 %− 71 % in initial stiffness, and by 35 %− 96 % in energy absorption under monotonic loading. Meanwhile, under cyclic loading, the GFRP-reinforced timber beams exhibited an increase by 22 %− 75 % in maximum load, by 58 %− 90 % in initial stiffness, and by 19 %− 37 % in energy absorption. On other hand, the flexural moment resistance of GFRP-reinforced timber beams predicted by the section analysis depicts a good agreement compared to experimental results.

Effect of different surface treatments on the repair bond strength between aged and new alkasite based restorative material.

This study investigates various surface treatment methods to assess shear bond strength between set Cention N (alkasite-based restorative material) and new alkasite based restorative material. Assessing different surface treatments provide insights in optimizing repair procedure that enables durability of the restoration, thus potentially benefitting clinical outcomes. A total of 48 alkasite based restorative material blocks, measuring 4 mm in depth and 4 mm in diameter, were prepared. The samples were randomly divided into 8 groups (n = 6) according to the surface treatment done. Group I: Surface preparation by bur; Group II: Surface treatment by laser; Group III: Application of 2-step etch and rinse adhesive (Adper Single Bond 2 adhesive),Group IV: Application of single step self-etch adhesive (Scotchbond Universal adhesive); Group V: Bur preparation followed by application of 2-step etch and rinse adhesive; Group VI: Bur preparation followed by application of single step self-etch adhesive; Group VII: Laser preparation followed by application of 2-step etch and rinse adhesive; and Group VIII: Laser preparation followed by application of single step self-etch adhesive. Post-surface preparation, all the specimens were restored with newly mixed alkasite material. Repair bond strength measurements were assessed with universal testing machine. Shapiro-Wilk and Levene's tests were used to check normality and Homogeneity of variance. ANOVA with post-hoc Games-Howell test and two-way ANOVA with post-hoc Bonferroni test was performed to evaluate the influence of surface preparation on the repair bond strength. Using a 2-step etch and rinse adhesive resulted in a higher repair bond strength (26.05±2.12) compared to other surface treatments. In contrast, roughening of the surface with burs led to lowest repair bond strength (17.06±3.29) (P=0.02). Application of 2-step etch and rinse adhesive to the existing alkasite based restorative material provides superior bonding with the newly added alkasite based restorative material.

Electric field envelope focality in superficial brain areas with linear alignment montage in temporal interference stimulation

Temporal interference stimulation (TIS) uses two pairs of conventional transcranial alternating current stimulation (tACS) electrodes, each with a different frequency, to generate a time-varying electric field (EF) envelope (EFE). The EFE focality in primary somatosensory and motor cortex areas of a standard human brain was computed using newly defined linear alignment montages. Sixty head volume conductor models constructed from magnetic resonance images were considered to evaluate interindividual variability. Six TIS and two tACS electrode montages were considered, including linear and rectangular alignments. EFEs were computed using the scalar-potential finite-difference method. The computed EFE was projected onto the standard brain space for each montage. Computational results showed that TIS and tACS generated different EFE and EF distributions in postcentral and precentral gyri regions. For TIS, the EFE amplitude in the target areas had lower variability than the EF strength of tACS. However, bipolar tACS montages showed higher focality in the superficial postcentral and precentral gyri regions than in TIS. TIS generated greater EFE penetration than bipolar tACS at depths <5–10 mm below the brain surface. From group-level analysis, tACS with a bipolar montage was preferred for targets <5–10 mm in depth (gyral crowns) and TIS for deeper targets. TIS with a linear alignment montage could be an effective method for deep structures and sulcal walls. These findings provide valuable insights into the choice of TIS and tACS for stimulating specific brain regions.

Fatigue crack detection in orthotropic steel deck bridges applied by FMC/TFM using reflected waves of multiple paths (1)

We introduce the latest developed FMC/TFM (Full Matrix Capture and Total Focusing Method) and its application for fatigue crack detection in orthotropic steel deck bridge. This developed inspection system consists of the advanced high-speed ultrasonic inspection equipment and the remotely operated four-wheel scanner with a 32- channel ultrasonic array probe for angle beam inspection. We developed MP-FMC/TFM (Multiple Paths Phased- array FMC/TFM) in this project. MP-FMC/TFM enables to visualize outline image of cracks clearly by image synthesis based on the propagation route information of direct path and the other paths reflected on the bottom of an inspection object against clacks. This developed inspection system enables to generate clear B-scope images of deck plate crack and bead (in deck-to-rib weld) crack with high-resolution. Furthermore, it enables to synthesizes 3D images of crack propagation with high-resolution along the weld line in real time by integrating the B-scope images every time the scanner moves 2mm. As a result of verification test of fatigue crack propagation test specimens, it was confirmed that this inspection system enables to visualize crack shape clearly and to achieves measurement accuracy of ±0.8mm for depth of deck plate crack, and ±1.0mm for depth of bead crack. Currently, verification tests are being conducted on an actual bridge, and practical application is planned in near future.

Histological Evaluation of Effect of Thymosin Beta 4 on Wound Healing of Skin

Skin wound healing is a normal biological process, achieved through four precisely and highly programmed phases: 1.hemostasis, 2.inflammation,3. proliferation, 4. remodeling. For a wound to heal successfully, Thymosin beta 4 (Tβ4) is a highly conserved, naturally occurring, water-soluble regenerative peptide that has biological activities of promoting angiogenesis, anti-inflammation, anti-apoptosis, and anti-fibrosis, and has many important functions in wound repair. This study aims to histologically examine the effect of systemic Thymosin beta 4 treatment with regard to skin wound healing in rats. A total number of 36 Western Albino rats with body weight (250-350 gm) and aging from(1-2 months) divided into two main groups each group was subdivided into 3 subgroups (6 rats in each) according to the healing period (1,3 and7 days). Full thickness wound of circular area 2 mm in depth was made on the dorsum of each rat with sterile biopsy punch of 5 mm diameter. The present study show role of Tβ4 in increase wound contraction, inflammatory cell and blood vessels proliferation at certain day of wound healing. Exogenous Tβ4 has bioactive role in wound healing when administrated systemically as it accelerate healing process at certain phases.