Volumetric Loss Research Articles

Topographic–Vegetation Interactions on an Incipient Foredune Field Post-Tropical Storm

Sand dunes protect the most important economic and ecologically critical landscapes from coastal hazards (storms and high-tide flooding). The characteristics of the dune affect their protective ability. This paper qualitatively and quantitatively assesses the relationships between pre- and post-storm conditions for vegetation and the morphology of an incipient dune system along the South Carolina coast. Field-based dune vegetation and morphology measurements were obtained before and after tropical storm Dorian (2019). Vegetation is assessed with respect to distribution and functional type, and subgroups are introduced to categorize land cover transitions. At the quadrat scale (0.2 m2) following the storm, there was a shift from stabilizer to builder, a decrease of sand (2%), and the vegetation remained consistent at around 61% of the land cover. Transect-level analysis (0.2 m × 1.0 m) revealed distinct variability concerning post-storm morphology change in the extreme study site extents. Dorian resulted in approximately 10% volumetric loss over the entire study site (101 m2). This study demonstrated changes to a dune system following a tropical storm with wind as the dominant forcing factor. This study revealed that vegetation presence is not broadly correlated with reduced levels of post-storm erosion.

Diabetes mellitus exacerbates inflammation in a murine model of ligature-induced peri-implantitis: A histological and microtomographic study.

To investigate the influence of diabetes mellitus (DM) in a murine model of peri-implantitis (PI). Twenty-seven 4-week-old C57BL/6J male mice had their first and second maxillary left molars extracted. Eight weeks later, one machined implant was placed in each mouse. Four weeks after osseointegration, the mice were divided into three groups: (a) control (C), (b) PI and (c) DM + PI. DM was induced by streptozotocin (STZ) administration. After DM induction, PI was induced using ligatures for 2 weeks. The hemimaxillae were collected for micro-CT and histological analyses. The primary outcomes consisted of linear (mm) and volumetric (mm3) bone loss. Secondary outcomes were based on histological analysis and included inflammatory infiltrate, osteoclastic activity, matrix organization, composition and remodelling. Data are presented as means ± SEM. Statistical analyses were performed using one-way ANOVA, followed by Tukey's test. Gingival tissue oedema was detected in the PI and DM + PI groups. Micro-CT showed significantly increased linear and volumetric bone loss in the DM + PI group compared to the C and PI groups. H&E staining showed greater inflammatory response and bone resorption in the PI and DM + PI groups than in the C group. The DM + PI group had significantly higher osteoclast numbers than the C and PI groups. Picrosirius red stained less for types I and III collagen in the PI and DM + PI groups than in the C group. There was a significant increase in monocyte/macrophage (CD-11b) counts and matrix metalloproteinases (MMP-2 and MMP-8) marker levels and a significant decrease in the matrix metalloproteinases inhibition marker (TIMP-2) levels in the DM + PI group compared to the C and PI groups. DM exacerbates PI-induced soft-tissue inflammation, matrix degradation and bone loss.

Acidic/abrasive challenges on simulated non-carious cervical lesions development and morphology

This in vitro investigation assessed how frequency of erosive challenges and duration of toothbrushing abrasion influenced non-carious cervical lesions (NCCLs) development and morphology. Experimental units were prepared using extracted human premolars assigned to four erosive-abrasive frequency protocols (n=16): F0. No acid exposure (negative control), F2.5 K. Acid exposure (1 % citric acid at natural pH) every 2500, F5K. 5000 and F15K. 15000 brushing-strokes. All groups were brushed for 55000 total brushing-strokes. Three-dimension images of the teeth were captured at baseline, after 15000, 35000 and 55000 brushing-strokes, using an intraoral scanner (TRIOS4, 3Shape). WearCompare software (Leeds Digital Dentistry) was used to analyze volumetric tooth loss (mm3) by superimposition followed by subtraction analysis. Lesion angle was measured (ImageJ, NIH) and morphology visually classified. Data were analyzed using ANOVA and Fisher's Exact tests adopting two-sided 5 % significance level. Tooth loss increased with brushing-strokes overall (p<0.001) and for each erosive-abrasive protocol (p<0.001). Acid exposure significantly increased tooth loss (p<0.001), regardless of brushing interval (p<0.001), however by 35000 strokes no tooth loss difference was observed among acid-exposed groups (p>0.05). Control had significantly sharper mean lesion angle (59°) than all acid-exposed groups (∼145°) (p<0.001), and significantly different lesion shape with 94 % wedge-shaped lesions versus 0 %, respectively (p<0.001). In contrast to the control, acid exposure was associated to more striated lesions. Simulated NCCLs developed and progressed differently and more rapidly in the presence of acidic challenges, regardless of their frequency. Exposure to acid impacted the morphology of lesions.

Circumferential Labral Reconstruction With Knotless All-Suture Anchors Restores Hip Distractive Stability: A Cadaveric Biomechanical Analysis.

The essential component of managing femoroacetabular impingement involves restoration of the original labral function. Circumferential labral reconstruction (CLR) has shown positive results. However, biomechanical studies of CLR are limited and have not established the efficacy of the modern knotless all-suture anchor (ASA) pull-through technique. (1) CLR with knotless ASA fixation will restore native labral suction seal biomechanics; (2) tensioning the ASA to a high-tension state will increase the peak distractive force. Controlled laboratory study. Eight fresh-frozen human cadaveric hips were dissected free of all soft tissue except the native labrum and transverse acetabular ligament. On an electromechanical testing system, the hips were compressively loaded to 250 N to initiate a suction seal and distracted at a rate of 10 mm/s until rupture of the suction seal. Hips were tested in 4 states: intact labrum, full labral removal, knotless CLR with moderate anchor tension, and CLR with high anchor tension. Peak distractive force (in newtons) was compared using repeated measures analysis of variance (P < .05). Acetabular bevel angles (θ) were measured at labral clockface positions outside the transverse acetabular ligament using a 3-dimensional digitizer stylus after rim preparation. Linear regression plots compared θ and peak distractive force in the CLR state. Peak force values were 138.5 ± 13.6 N (mean ± SE) for the intact labrum, 18.4 ± 2.79 N for labral excision, 95.4 ± 23.3 N for moderate-tension CLR, and 126.2 ± 27.3 N for high-tension CLR. Significant differences were observed only when full labral removal was compared with the other conditions: intact (P < .001), moderate-tension CLR (P = .016), and high-tension CLR (P = .002). Steeper acetabular bevel angles (smaller θ) were correlated with greater suction seal restoration (P < .05). CLR restored distractive stability on average to 82.0% of the intact value after labral deficiency. Retensioning did not significantly increase peak distractive forces. These findings provide biomechanical validation supporting CLR using knotless ASAs in an effort to minimize volumetric bone loss and provide other surgical advantages. The prepared rim's bevel angle may be an important variable to optimize for improved suction seal restoration.

PROBLEMS OF CHOOSING A METHOD OF DENTAL TREATMENT OF TEETH AFTER ENDODONTIC INTERVENTION

The optimal way to restore the anatomical structure of teeth after endodontic intervention is a controversial topic. Teeth after endodontic intervention have different properties compared to intact living teeth. Changes in these properties are associated with volumetric loss of hard tissues, caries, final preparation of the cavity taking into account access to endodontic treatment. Choosing the optimal method of dental treatment of teeth requires compliance with many factors, such as: prevention of infection penetration into root canals, restoration of tooth contacts, restoration of chewing functions, protection against further carious and non-carious destruction, restoration of tooth aesthetics. Dentists are now more than ever aware of the interdependence of the endodontic and restorative aspects of dental treatment and how much this will affect achieving the best long-term outcome. Controversies of the clinical relevance of endodontic and restorative treatment choice issues are mostly unanswered based on clinical data and scientific evidence. The modern approach to tooth restoration after endodontic intervention is an important topic. To improve clinical outcomes, it is important to determine the effectiveness of treatment, the importance of preserving tooth structure, the choice of treatment method with restorative materials, and the integration of digital dentistry to improve diagnosis and treatment principles. Research rationale. The purpose of this study is to find and use literature data on the effectiveness of modern methods of dental treatment after endodontic intervention in Ukraine. Materials and methods. Scientific data from a review and systematic analysis of the literature were used. Materials were searched using the Google Scholar, PubMed, Google Scholar databases and open sources of the World Health Organization, the Ministry of Health of Ukraine and other government web portals of Ukraine. Results, Discussion. After conducting a literature analysis to compare the effectiveness of using cast metal inserts and fiberglass posts, we can come to the conclusions that retrospective studies on the relationship between successful restorations and such factors as the type of tooth, the volume of residual hard tissues, the number of occlusal contacts, the type of the final restoration and the position of the tooth in the dental arch are the main criteria for choosing a treatment method. A controversial choice is that metal abutments are associated with a higher risk of root fracture, their manufacture requires laboratory techniques, while the use of fiberglass posts is associated with a higher risk of decementation, and overloading of fiberglass posts leads to their fractures. Conclusions. Decision-making and the choice of methods of dental treatment after endodontic intervention remain difficult. However, the interdependence of endodontic treatment and restoration of the crown part of the tooth is clearly established. Physicians must consider both aspects of treatment equally to ensure the best possible outcomes for their patients. The use of digital scanning enables an accurate volumetric assessment of the residual hard tissues of the tooth, which can be used to provide tangible qualitative results of the analysis and decision-making with the choice of treatment method. The choice of treatment method is not defined in a single protocol and requires further careful study with new experimental developments, based on the latest technologies of world leaders in dentistry.

Comparative study on surface wettability, bio-tribology, and cytotoxicity of selective laser melted 316L SS, CoCrMo, and Ti6Al4V metallic biomaterials

The present work deals with fabricating metallic implant surfaces through laser powder bed fusion-based selective laser melting (SLM) technique using the 316L SS, CoCrMo, and Ti6Al4V powders. The topographical, metallographic, and micro-hardness measurements were performed to study the fabricated parts’ surface roughness, chemical purity, and mechanical behavior. The results showed that prepared selective laser melted (SLMed) samples have nano-level roughness, high chemical purity, and improved hardness value. Further, the surface functionality was examined through surface wettability and cytotoxicity analysis, and it was found that the Ti6Al4V sample exhibits an improved hydrophilicity with a minimum contact angle (CA) value of 26.25° as compared to the 316L SS (CA: 40.23°) and CoCrMo (CA: 44.54°) samples. The cytotoxicity results for 100 % dilution indicate that the CoCrMo sample has the highest cell viability (CV: 170.03 ± 13.91), followed by 316L SS (CV: 139.47 ± 2.2) and Ti6Al4V (CV: 101.53 ± 15.44) specimens. Furthermore, the in-vitro bio-tribology analysis indicated that SLMed samples have improved friction and wear performance, with the lowest COF value of 0.12 for Ti6Al4V at 10N load as compared to the 316L SS and CoCrMo parts. However, the Ti6Al4V surface presented a high volumetric wear loss compared to 316L SS and CoCrMo counterparts at different loads, indicating a brittle behavior. The obtained outcomes dictate that the SLM technique is a promising approach to fabricating implant surfaces using Ti6Al4V metallic biomaterial with improved bulk and surface functionality.

Quantifying preserved renal volume and function in patients undergoing standard partial nephrectomy vs. tumor enucleation for localized renal tumors

IntroductionRenal parenchymal volume loss from standard partial nephrectomy (SPN) is a significant prognosticator for postoperative renal function. Tumor enucleation (TE) minimizes parenchymal loss compared to SPN. Little is known regarding discrete changes in renal function associated with volume loss. We sought to quantify the differences between SPN and TE in preserving parenchymal volume and estimated glomerular filtration rate (eGFR). MethodsWe identified 420 patients who underwent robotic partial nephrectomy (SPN or TE) at our tertiary care center from 2009 to 2022. Parenchymal volumes were calculated using TeraRecon 3D reconstruction software from axial imaging performed preoperatively and within 6 months postoperatively. Renal volume preserved and renal function were evaluated with multivariable linear and logistic regression models. ResultsAt 1 year, eGFR was 7% lower in patients undergoing SPN compared to TE (P < 0.01). Across both SPN and TE, only volume of preserved parenchyma was predictive of eGFR and chronic kidney disease (CKD) progression (both P < 0.01). TE preserved more healthy parenchymal volume compared to SPN (median percentage 97.6% vs 89.2%; P < 0.001). Each 1% of volumetric loss corresponded to a 0.35% decrease in eGFR at 1 year postoperatively (P < 0.01). ConclusionsVolume of preserved renal parenchyma was the strongest factor associated with preserved eGFR and reduced odds of CKD progression. TE preserved more parenchyma than SPN, which translated to higher eGFR preservation at 1 year postoperatively.

A Comparative Evaluation of Real-Time Guided Dynamic Navigation and Conventional Techniques for Post Space Preparation During Post Endodontic Management: An In Vitro Study.

The three-dimensional (3D) dynamic navigation system (DNS; Navident, ClaroNav Technology, Toronto, ON) is a revolutionary technique in endodontics that offers superior precision and efficiency compared to existing techniques for post space preparation. The aim is to evaluate and contrast the efficacy and efficiency of the DNS with conventional post space preparation techniques. This assessment considers severalparameters, notably canal deviation (global coronal and apical deviation and angular deflection), duration of the procedure, and total volumetric loss of instrumented root canal and volumetric loss of instrumented root canal above 4 mm from the apex. Freshly extracted maxillary central incisors were chosen for this study. A total sample size of 60 (n) was included. The extracted teeth samples were divided into two groups: 3D DNS (group I; n = 30)and conventional techniques (group II; n = 30). The samples were taken, and 50% of the crown structure was reduced for post space preparation to ensure standardization between thetwo groups. The samples were root canal-treated and mounted in a 3D-printed maxillary cast. Preoperative micro-computed tomography (micro-CT) and cone-beam computed tomography (CBCT) were taken for both groups.For group I, post space preparation was conducted with the DNS, which provided comprehensive guidance. The procedure was stopped when post space preparation was 4 mm short of the apex, as indicated in the system display. For group II, post space preparation was done without the guidance of DNS. Time taken for the procedure was assessed using a timer; canal deviation was evaluated using CBCT analysis, and volumetric loss was estimated using micro-CT analysis. The dynamic navigation group achieves significantly more precise outcomes in post space preparation than the conventional technique. The DNS group has significantly lesser global coronal and apical deviation and angular deflection compared to the conventional group (p < 0.05). The DNS group has reduced the volumetric loss of instrumented root canals compared to the conventional group (p < 0.05). Furthermore, the DNS group requires significantlyless time than the conventional method, with a mean difference of about 10.567 minutes (p < 0.05). Implementing dynamic navigation improves precision in post space preparation, with a notable reduction in canal deviation and volumetric loss and a decrease in procedure time compared to the conventional method.

Volumetric change of calcium silicate-based repair materials in a simulated inflammatory environment: A micro-computed tomography study

Context: An acidic hydrogen potential (pH) in an inflammatory condition in the periapical tissues may affect the properties of repair bioceramic cement. Aims: The aim of this study was to evaluate the effect of pH on the volumetric change of the ready-to-use bioceramic NeoPUTTY (NP) compared to the powder/liquid MTA Repair HP (MTAHP) after immersion in butyric acid (BA, pH 4.1) or phosphate-buffered saline (PBS, pH 7.35). Subjects and Methods: Dentin tubes filled with NP or MTAHP were scanned in micro-computed tomography (micro-CT) after 24 h. Then, the specimens were immersed in 1.5 mL of BA: NP/BA, MTAHP/BA or PBS: NP/PBS, MTAHP/PBS. After 7 days, new micro-CT scans were performed. The percentage of volumetric change (extremities and internal part) of the materials was assessed. Statistical Analysis Used: ANOVA/Tukey and Kruskal–Wallis tests were performed (α =0.05). Results: All materials showed a volumetric decrease after immersion in BA or PBS at the extremities in contact with the solutions. MTAHP/BA showed the highest volumetric loss. There was no difference in the volumetric change when the internal part of the materials was evaluated. Conclusions: An acid pH negatively affects the volumetric stability of MTAHP. Low values of volumetric change were demonstrated for NP in both immersion environments.

The effect of niobium carbide coating on wear behavior of grey cast iron via thermo-reactive diffusion process

Wear is the limit for grey cast iron (GCI), which is utilized extensively in today’s industries. Coating the surface of a material can enhance its ability to withstand wear. In this study, thermo-reactive diffusion (TRD) process was used to coat the surface of grey cast iron with niobium carbide (NbC). The coatings were applied for 2, 4 and 6 hours at 950ºC and 1050ºC. The coated samples were subjected to metallographic examination to investigate the microstructure of the coating zone. For this purpose, optical microscopy examinations were carried out. Microhardness tests were carried out to assess the mechanical properties of the samples. The coated surfaces were analyzed using energy-dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Wear tests were carried out on the coated surfaces to measure the volumetric wear loss, the wear rate and the changes in the coefficient of friction. Coating thickness rose as furnace waiting time increased, according to optical microstructures of coated surfaces. The hardness of the coated surfaces increased with a longer coating duration. Depending on the duration and temperature of the coating process, the layer thickness ranged from 6 to 52 µm. The lowest microhardness and the highest microhardness values of the coatings were determined at 950ºC for 2 hours and at 950ºC for 6 hours, respectively. Compared to the uncoated samples, the coated samples had a 6-9 times higher hardness value. In the abrasion tests, the loss of wear volume increased with increase in load.

Tooth Tissue Loss in Locating Mesiobuccal Canal during Selective Retreatment using Dynamic Navigation System: An In vitro Study

Selective root canal retreatment has demonstrated positive success, but the process is challenging because imprecision compromises the tooth's structural durability. As there is a lack of literature on selective retreatment using DNS, this in-vitro study was designed for comparative evaluation of tooth tissue loss and time taken in locating mesiobuccal (MB)canal using the dynamic navigation system (DNS; Navident, ClaroNav, Toronto, ON, Canada ) to the freehand (FH) method. The null hypothesis was that both methods would have similar tooth tissue loss and time required for the procedure. Twenty root canal-treated human mandibular molar teeth were mounted on Navident manikin. Using the Navident programme, the drilling path and depth were virtually designed using cone-beam computed tomographic (CBCT) scans. A minimal access cavity for locating the MB root was prepared with dynamic navigation in the DNS group and with freehand in the FH group. Volumetric tooth tissue loss was evaluated with the help of postoperative CBCT and On-demand software. Statistical analysis was done with an independent-sample T Test (p&lt;0.05). The time taken for the procedure was recorded with a stopwatch. The tooth tissue loss was significantly less with the DNS group (35.83 mm3) compared to the FH group (52.84 mm3) with a P value of 0.001. The time taken for the DNS group was less with the DNS group (29.00 seconds) compared to the FH group (53.60 seconds) with statistical significance with a P value of 0.001. The DNS resulted in minimal tooth tissue loss with a shorter time compared to the FH group. This technique can be practised for predictable selective retreatment in endodontics.

Synergistic Effect of B4C and Multi-Walled CNT on Enhancing the Tribological Performance of Aluminum A383 Hybrid Composites

The requirement for high-performance and energy-saving materials motivated the researchers to develop novel composite materials. This investigation focuses on utilizing aluminum alloy (A383) as the matrix material to produce hybrid metal matrix composites (HMMCs) incorporating boron carbide (B4C) and multi-walled carbon nanotube (MWCNT) through a cost-effective stir casting technique. The synthesis of HMMCs involved varying the weight fractions of B4C (2%, 4%, and 6%) and MWCNT (0.5%, 1%, and 1.5%). The metallographic study was carried out by field emission scanning electron microscopy (FESEM) mapped with EDS analysis. The results indicated a uniform dispersion and robust interfacial interaction between aluminum and the reinforced particles, significantly enhancing the mechanical properties. Micro-hardness and wear characteristics of the fabricated HMMCs were investigated using Vickers microhardness testing and the pin-on-disc tribometer setup. The disc is made of hardened chromium alloy EN 31 steel of hardness 62 HRC. The applied load was varied as 10N, 20N, 30N with a constant sliding speed of 1.5 m/s for different sliding distances. The micro-hardness value of composites reinforced with 1.5 wt% MWCNT and 6 wt% B4C improved by 61% compared to the base alloy. Additionally, the wear resistance of the composite material improved with increasing reinforcement content. Incorporating 1.5% CNT and 6% B4C as reinforcements results in the composite experiencing about a 40% reduction in wear loss compared to the unreinforced aluminum alloy matrix. Furthermore, the volumetric wear loss of the HMMCs was critically analyzed with respect to different applied loads and sliding distances. This research underscores the positive impact of varying the reinforcement content on the mechanical and wear properties of aluminum alloy-based hybrid metal matrix composites.

Surface hardness and wear resistance of prefabricated and CAD‐CAM milled artificial teeth: A cross‐over clinical study

AbstractPurposeTo clinically evaluate the surface roughness and wear resistance of prefabricated and CAD‐CAM milled acrylic resin teeth for complete dentures.Materials and methodsIn a cross‐over study design, 10 completely edentulous patients were randomly included in this study and given two complete dentures. The first complete denture was made using prefabricated teeth, while the second was constructed using CAD‐CAM milled teeth. Following insertion (T0), 3 months (T3), and 6 months (T6), the complete dentures were scanned. Utilizing 3D surface super‐imposition techniques, the vertical (2D wear), and volumetric (3D wear) material loss were measured. The hardness of the teeth was evaluated at the time of denture insertion (T0) and then after 6 months (T6) of denture insertion by digital Vickers hardness tester. Statistical analysis was done using SPSS software. Paired groups were compared by paired t‐test. Also, a repeated measure test was used. The significant difference was considered if p ≤ 0.05.ResultsThe time of denture function was linearly correlated with the wear of the prefabricated and CAD‐CAM milled denture tooth. Prefabricated acrylic teeth had significantly more vertical and volumetric wear after 3 and 6 months, compared to CAD‐CAM milled denture teeth where p‐values were 0.01, 0.009, 0.003, and 0.024, respectively. Additionally, CAD‐CAM milled teeth displayed significantly higher hardness values than prefabricated teeth both before and after 6 months of use where p‐values were 0.001. After 6 months, all studied teeth showed a decrease in their hardness.ConclusionsIn terms of wear resistance and surface hardness, CAD‐CAM milled acrylic resin teeth were superior to prefabricated acrylic resin artificial teeth once the complete denture functions.

Evaluation of wear resistance and surface properties of additively manufactured restorative dental materials

ObjectivesTo evaluate the wear resistance of three additively manufactured dental crown materials (NextDent C&B MFH, Saremco print CROWNTEC and Bego VarseoSmile Crown) under two environmental conditions (dry and artificial saliva), two loads (49 N and 70 N) and two surface treatments (polished and glazed). MethodsA total of 120 specimens were divided into 24 groups and tested for wear under two loads (49 N and 70 N), surface treatment (polished or glazed), and environment (dry or submerged in artificial saliva). All samples underwent reciprocating wear testing at 1 Hz using a wear simulator, replicating 48 months of In Vivo conditions with a stainless-steel ball as the antagonist. The coefficient of friction (CoF), surface roughness, volumetric and vertical wear loss were measured and statistically analysed. Confocal microscopy assessed the surface properties of crown materials and the antagonists. ResultsThe NextDent material demonstrated the most homogenous wear, with relatively low vertical and volumetric loss across all groups (p < 0.004). NextDent and Bego materials performed similarly in artificial saliva regardless of the load type (p > 1.000). The CoF remained below 0.3 for all groups. All groups exhibited significant increases in surface roughness after testing, however, this did not correlate with an increase in the CoF. Confocal analysis revealed material deformities due to load and notable scratch marks on the stainless-steel antagonists. ConclusionIt was found that all investigated addtively manufactured materials can be suggested for provisional use. Both vertical loss and volumetric loss results should be included for material evaluation. CoF and surface roughness should be implemented into wear evaluation. Clinical significanceThis study highlights the practical value of additively manufactured dental crown materials, particularly for provisional restorations. However, their extended use requires careful consideration of individual patient needs, emphasising the need for judicious clinical application evaluation.

Investigating the wear resistance of AISI 410/AISI 2205 hybrid weld cladding on annealed EN 8 medium carbon steel

A new multi-layer and multi-material hybrid configuration of weld cladding an annealed EN 8 substrate has been developed and investigated. The AISI 410 martensitic stainless steel is used as the bottom and top clad layers and the AISI 2205 duplex stainless steel is used as the middle weld cladding layer which creates a composite multi-material clad structure with distinct interfacial characteristics. Examination of microstructure unveiled lamellar morphology of the top layer with martensitic-austenitic constituents with maximum hardness, whereas the intermediate layer exhibited ferritic-austenitic morphology with lower hardness. The bottom layer exhibited a tempered martensite structure with a relatively smaller grain size and exhibited intermediate hardness. The bottom-substrate interface displaying the highest interfacial hardness, followed by the middle-bottom interface and the top-middle interface in descending order. Incorporation of AISI 2205 in the intermediate contributed to an increased toughness of 30 MPa√m. During the ball-on-flat sliding wear test, the coefficient of friction displayed an intriguing pattern after a critical load threshold. Higher applied loads led to decreased absorbed energy and a reduction in wear track dimensions. Elevated heat levels promoted tribofilm formation, contributing to lower wear rates, with the optimum condition observed at 7 N, displaying the lowest volumetric loss and wear rate. The primary wear mechanism predominantly involved plastic deformation and plowing, with no apparent indications of brittle fracture.

Exploring tribological properties in the design and manufacturing of metal matrix composites: an investigation into the AL6061-SiC-fly ASH alloy fabricated via stir casting process

This study investigates a novel methodology to intricately craft a HAMMC and thoroughly examine its multifaceted mechanical and tribological characteristics. By combining silicon carbide (SiC) and fly ash as reinforcements, a unique identity is bestowed upon this hybrid composite, enhancing its structural integrity and functional attributes. Stir casting is the chosen methodology for fabricating this composite, favored for its economic viability and suitability for large-scale manufacturing. In this research, the emphasis is on developing a cost-effective composite that not only meets stringent economic considerations but also exhibits improved material properties. Within the realm of hybrid metal matrix composites, the well-regarded Al6061 takes on the role of the matrix material, while the synergistic inclusion of fly ash and SiC serves as reinforcing constituents. Three specimens with compostion 90% Al6061 + 5% SiC +5% Fly ash, 90% Al6061 + 10% SiC +6% Fly ash and 90% Al6061 + 15% SiC +7% Fly ash were fabricated. To unravel the intricacies of the fabricated Al6061 metal matrix composite, comprehensive tests are employed. These tests, including the Pin-on Disc test, Scratch test, Rockwell Hardness test, and Charpy Impact test, collectively work to unveil the nuanced tribological and mechanical behaviors encapsulated within this innovative alloy. The results indicated significant improvement in wear resistance in specimen comprising 78% Al6061 + 15% SiC +7% Fly Ash and volumetric loss found to have 0.96 g. Superior hardness characteristics and enhanced abrasion resistance found in 78% Al6061 + 15% SiC +7% Fly Ash than other two specimens. The highest impact strength exhibited in 90% Al 6,061 + 5% SiC +5% Fly ash specimen.

New nano-lamellar eutectic high-entropy alloy coating by laser cladding

A novel Al27Cr25Ti18Nb18Zr12 eutectic high entropy alloy (EHEA) coating with BCC/B2 and Laves phase has been developed by laser cladding on Ti–6Al–4V alloys. The average microhardness of EHEA coating was ∼697.6HV0.3, which significantly surpasses the values reported for most eutectic high-entropy alloy coatings. The strengthening effect and additional strain hardening sources generated by the intersecting nanometer-spaced stacking faults and Lomer-Cotrell locks which found in BCC/B2 phase are important reasons for the superior hardness. And the adhesive problem of Ti–6Al–4V alloy was ameliorated by the EHEA coating with lower friction coefficient (83.05 % of the Ti–6Al–4V alloy) and volumetric loss (27.75 % of the Ti–6Al–4V alloy).

Enhanced Human Skeletal Muscle Cell Differentiation via the Inhibition of 15-Hydroxyprostaglandin Dehydrogenase

Musculoskeletal diseases, including sarcopenia, are increasingly affecting billions globally. Individuals afflicted with such diseases experience impaired ability to regenerate muscle following injury or volumetric loss. Regeneration is vital for maintaining healthy muscle function and muscle cell differentiation plays a significant role. Our previous studies show that Prostaglandin E2 (PGE2) increases mouse muscle cell differentiation and improves muscle function. Adequate levels of PGE2 in muscle are therefore required for proper regeneration. 15-Hydroxyprostaglandin dehydrogenase (15-PDGH) is an enzyme which degrades PGE2. Previously, studies in rat muscle cells that were treated with SW0033291 (referred hereafter as SW), an inhibitor of 15-PDGH, showed that muscle cell differentiation was enhanced. There is no published study of SW effects on human skeletal muscle myogenesis. Our hypothesis is that when human skeletal muscle cells are treated with SW, the differentiation will be enhanced. To study the effects of SW on human muscle cell differentiation, first the cytotoxicity of SW on human primary skeletal muscle cells (HPSMC) from a young healthy woman were treated with 25, 50, 100, 500 and 1000nM SW for 24h and 48h. No cytotoxicity of SW was detected in all SW-treated groups compared to control group (p&gt;0.05). The effects of SW on myogenic differentiation were measured on day 4 using the methodology of Fusion Index (FI). To study the molecular mechanisms of SW on myogenesis, the expression of myogenic regulator genes (MyoD, MyoG and Mhc) were analyzed by RT-qPCR after the treatment of SW. At day 4 of differentiation, compared to control, no obvious difference of FI was found in 25, 50, 100, and 500nM SW-treated groups (p &gt; 0.05), while a significant increase in FI was found in the 1000nM (p &lt; 0.05) SW0033291-treated group (p&lt;0.05). These results suggest that SW enhances HPMC differentiation. Compared to control, in 25, 50, 100, and 500nM SW-treated groups, the expression of all three genes was not significantly changed (p &gt; 0.05). In the 1000nM SW-treated group, the expression of the myogenic markers MyoD, MyoG and Mhc increased significantly (p &lt; 0.05) by 1.83±0.21-fold, 1.47±0.18-fold, and 2.09±0.37-fold, respectively. These findings confirm our original hypothesis that SW enhances HPSMC differentiation. In conclusion, these results show initial promising application for maintaining proper PGE2 levels and thus allowing for proper human muscle cell differentiation and potential clinical applications in a wide range of musculoskeletal disorders. This work was directly supported by NIH-National Institutes of Aging P01AG039355 (MB) and the George W. and Hazel M. Jay and Evanston Research Endowments (MB). Authors were supported by NIH Grants: National Institutes of Aging (NINDS) 2-R01NS105621; NIA-R01AG056504, NIA-2R01AG060341, National Institutes of Diabetes, Digestive, and Kidney Diseases Kidney (NIDDK)-1R01DK119066 to MB, and National Institutes of Neurological Disorders and Stroke (NINDS) 2-R01NS105621 to MB. Also, NIH/NIDC 1R01DE031872-01 (VV). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Multiprotein collagen/keratin hydrogel promoted myogenesis and angiogenesis of injured skeletal muscles in a mouse model

Volumetric loss is one of the challenging issues in muscle tissue structure that causes functio laesa. Tissue engineering of muscle tissue using suitable hydrogels is an alternative to restoring the physiological properties of the injured area. Here, myogenic properties of type I collagen (0.5%) and keratin (0.5%) were investigated in a mouse model of biceps femoris injury. Using FTIR, gelation time, and rheological analysis, the physicochemical properties of the collagen (Col)/Keratin scaffold were analyzed. Mouse C2C12 myoblast-laden Col/Keratin hydrogels were injected into the injury site and histological examination plus western blotting were performed to measure myogenic potential after 15 days. FTIR indicated an appropriate interaction between keratin and collagen. The blend of Col/Keratin delayed gelation time when compared to the collagen alone group. Rheological analysis revealed decreased stiffening in blended Col/Keratin hydrogel which is favorable for the extrudability of the hydrogel. Transplantation of C2C12 myoblast-laden Col/Keratin hydrogel to injured muscle tissues led to the formation of newly generated myofibers compared to cell-free hydrogel and collagen groups (p < 0.05). In the C2C12 myoblast-laden Col/Keratin group, a low number of CD31+ cells with minimum inflammatory cells was evident. Western blotting indicated the promotion of MyoD in mice that received cell-laden Col/Keratin hydrogel compared to the other groups (p < 0.05). Despite the increase of the myosin cell-laden Col/Keratin hydrogel group, no significant differences were obtained related to other groups (p > 0.05). The blend of Col/Keratin loaded with myoblasts provides a suitable myogenic platform for the alleviation of injured muscle tissue.

Late Changes in Renal Volume and Function after Proton Beam Therapy in Pediatric and Adult Patients: Children Show Significant Renal Atrophy but Deterioration of Renal Function Is Minimal in the Long-Term in Both Groups.

To compare late renal effects in pediatric and adult patients with malignancies after PBT involving part of the kidney. A retrospective study was conducted to assess changes in renal volume and function in 24 patients, including 12 children (1-14 years old) and 12 adults (51-80 years old). Kidney volumes were measured from CT or MRI images during follow-up. Dose-volume histograms were calculated using a treatment planning system. In children, the median volume changes for the irradiated and control kidneys were -5.58 (-94.95 to +4.79) and +14.92 (-19.45 to +53.89) mL, respectively, with a relative volume change of -28.38 (-119.45 to -3.87) mL for the irradiated kidneys. For adults, these volume changes were -22.43 (-68.7 to -3.48) and -21.56 (-57.26 to -0.16) mL, respectively, with a relative volume change of -5.83 (-28.85 to +30.92) mL. Control kidneys in children exhibited a marked increase in size, while those in adults showed slight volumetric loss. The percentage of irradiated volume receiving 10 Gy (RBE) (V10) and 20 Gy (RBE) (V20) were significantly negatively associated with the relative volume change per year, especially in children. The CKD stage based on eGFR for all patients ranged from 1 to 3 and no cases with severe renal dysfunction were found before or after PBT. Late effects on the kidneys after PBT vary among age groups. Children are more susceptible than adults to significant renal atrophy after PBT. V10 and V20 might serve as predictors of the degree of renal atrophy after PBT, especially in children. PBT has a minimal impact on deterioration of renal function in both children and adults.