Early Loading Research Articles

A Comparative Analysis of Marginal Bone Loss of Hydrophilic Implants versus non-hydrophilic Implants placed on Edentulous Ridge in Mandibular Implant Overdenture

Objective: This systematic review aims to evaluate the clinical outcomes of hydrophilic versus non-hydrophilic dental implants, focusing on key parameters such as marginal bone loss, implant survival rates, and bone-to-implant contact (BIC). The review seeks to determine whether hydrophilic surfaces offer a significant clinical advantage and to identify areas for future research. Materials and Methods: A comprehensive literature search was conducted across databases including PubMed, Scopus, and Cochrane Library, covering studies published from 2015 to 2023. Inclusion criteria were randomized controlled trials, prospective and retrospective studies, and in vivo experiments comparing hydrophilic and non-hydrophilic implants. Data extraction focused on outcomes related to marginal bone loss, implant survival, and BIC. Studies were assessed for methodological quality using the Cochrane Risk of Bias tool and the Newcastle-Ottawa Scale. Results: A total of 10 studies met the inclusion criteria, encompassing 450 implants in various clinical settings. The findings revealed that hydrophilic implants generally demonstrated lower marginal bone loss and higher BIC percentages compared to non-hydrophilic implants, with survival rates exceeding 97% in most studies. However, the differences in outcomes were not consistently significant across all studies, highlighting variability in results based on implant type, patient demographics, and follow-up duration. Conclusion: Hydrophilic implants show potential advantages in terms of marginal bone loss and BIC, particularly in early loading protocols. However, further long-term studies with standardized methodologies are needed to confirm these benefits and optimize clinical guidelines for implant selection.

Asymmetric deformation and failure behavior of roadway subjected to different principal stress based on biaxial tests

The magnitude and direction of stress will affect the failure of roadway. The impact of stress magnitude and direction on roadway failure was investigated using a rock failure system equipped with true triaxial loading, acoustic emission (AE), and digital image correlation (DIC) technologies. The system allowed for the simulation of rock sample failures under various three-dimensional stress conditions, while real-time monitoring was conducted using a high-precision microseismic system. By prefabricating rectangular holes at different angles in sandstone specimens, roadways under different stress effects in engineering can be simulated. Biaxial loading tests were then performed on these prefabricated sandstone cube specimens to observe external fracture characteristics and internal fracture information using acoustic emission equipment. The peak strength of samples with holes is approximately 38–56% of that of intact samples. In the early and middle loading stages, the strain on the surface is on the order of 10-3. In the later loading stage, the strain on the surface is on the order of 10-2. The findings indicate that roadway failure primarily involves local particle ejection, fragment spalling, large-scale particle ejection, plate crack buckling, and eventual failure. The ultimate failure mode varies based on stress deflection angles: with no included angle, the roadway exhibits a ’V’ shaped failure zone on both sides, predominantly experiencing tensile failure. At included angles of 30°, 45°, and 60° between stress and roadway axis, the roadway displays a “—” failure pattern along the diagonal, characterized by a combination of tension and shear failure. The extension angle of the“—” failure zone varies depending on the stress deflection angle. At a 90° included angle, the roadway shows a ’V’ shaped failure in the roof and floor, primarily undergoing tensile failure. Real-time monitoring of the strain field evolution around the roadway during failure using DIC method revealed valuable insights. AE events at different deflection angles reflect the progression of micro cracks in the specimen, showing a strong correlation with macro failure. The research outcomes elucidate the mechanisms behind various forms of roadway failure induced by stress deflection and shed light on the failure mechanism at different stress deflection angles.

No Difference in Systolic Dysfunction from Left Ventricular Pressure-Volume Loop’s Area and Stroke Work Between Chronic Late Load vs. Early Systolic LV Load in Porcine Model

<i>Background: </i>in increased LV afterload as in hypertension, early systolic LV dysfunction (SD) in late compares to early peak systolic LV load for P-V area, stroke work, potential energy with effective LV work (EW) is not being defined (aortic stenosis, arterial hypertension or coarctation of the aorta) in LVH remodeling. <i>Objectives:</i> to assess in porcine model how LV stroke work, PVA and EW are related to LVH remodeling in developing early SD with HF, between 4<sup>th</sup> vs 8<sup>th</sup> week in chronic LL compares to EL. It is suggested that reduced proximal thoracic or asc. aortic compliance results with myocardial ischemia. However, difference for LV O<sub>2</sub> demand and effective LV work in different LV afterload is not understood in early development systolic HF. <i>Methods:</i> in fourteen domestic male pigs (28±3 kg) with moderate descending aortic banding having chronic late LV load (LL=8) or ascending aortic stenosis with early systolic LV load (EL=6) SD was assessed, from PVA, in invasive LV pressure-volume loops’ measurements, at 4<sup>th</sup> vs. 8<sup>th</sup> week, to assess LV maximal ESPVR, with Millar 5Fr P-V pig-tailed conductance catheter. LV stroke work, and pressure-volume area PVA, reflecting the maximal LV O<sub>2</sub> demand were assessed in chronic LL compares to EL from nonlinear regression analysis of maximal LV end-systolic stiffness, in special software. For variance analysis, two-way repeated measures ANOVA was performed, with normality assessment. Results are means±(SEM) or medians for significant p<0.05. <i>Results: </i>LV PVA was not different, in LL compared to EL at 4<sup>th</sup> vs. 8<sup>th</sup> week. LV stroke work with effective works were not different and potential energy, neither were changed between 4<sup>th</sup> vs. 8<sup>th</sup> week. No difference was found in different LV afterload, in both indexed and absolute LVO<sub>2</sub> demand, in LL vs. EL at 4<sup>th</sup> or 8<sup>th</sup> week. Indexed PVA parameters with LV stroke work, effective work and potential energy were not different or changed in LL compares to EL between 4<sup>th</sup> vs. 8<sup>th</sup> weeks, normalized per body surface-area (in m<sup>2</sup>). <i>Conclusion:</i> Both absolute and indexed LV stroke work, potential LV energy, PVA with EW and maximum LV O<sub>2</sub> demand are not different in LL compares to EL at 4<sup>th</sup> vs. 8<sup>th</sup> week of LVH remodeling, indicating no difference in early SD development in increased late vs. early LV afterload.

Study on bending performance of prefabricated glulam-cross laminated timber composite floor

Abstract The glulam-cross laminated timber (CLT) composite floor is a type of prefabricated composite floor that integrates glulam beams and CLT slab into a unified structure using shear connectors. To investigate the bending performance of the glulam-CLT composite floor, the bending test was conducted on a full-scale composite floor under static load. The study comprehensively analyzed the failure mechanism, load–deflection behavior, interface slip and strain distribution of the glulam-CLT composite floor. The test results of the composite floor indicated that the failure mode was tensile fracture of the wood beam at the bottom. As the load increased, the deflection deformation of the mid-span beam exceeded that of the edge beam. When the load reached its ultimate limit, the deflection deformation of the mid-span beam increased by 14.4% compared to the edge beam. In the early loading phase, the strain distribution of the composite section satisfied the assumption of a plane section. However, the strain distribution deviated from this assumption with the increased load due to the relative slips between the glulam beam and CLT flange. To calculate the bending performance of the composite floor, the M-shaped section of the glulam-CLT composite floor was simplified as T-section composite beams. The linear-elastic method for determining the flexural rigidity and ultimate bearing capacity of the glulam-CLT composite floors was proved to be accurate and reliable. The findings provided valuable insights into the bending behavior of the CLT flange under load and emphasized the non-uniform stress distribution caused by shear lag effects.

Multimodal assessment of mechanically induced transformation and damage in TRIP steels using X-ray nanotomography and pencil-beam diffraction tomography

A comprehensive multimodal measurement environment integrating X-ray computed tomography (CT) and special X-ray diffraction (XRD) using a collimated beam has been developed and was applied for the first time to investigate martensitic transformation and damage behaviour in transformation-induced plasticity (TRIP) steels. The transformation and damage behaviour of numerous γ grains were analysed individually to understand the behaviours and to identify the factors controlling these processes.A transition was observed from a stress-assisted transformation in the early loading phase, controlled by mechanical driving forces, to a strain-induced transformation controlled by dislocation density. A characteristic reversal in the transformation rate was observed whereby γ grains with a crystallographic orientation that initially undergo rapid transformation due to high mechanical driving force underwent a sudden deceleration of transformation. Conversely, γ grains with an orientation that initially underwent gradual transformation rapidly completed transformation. The preceding hard phase inhibited the transformation of neighbouring γ grains through the triple effects of reducing stress triaxiality, relaxing stresses and constraining plastic deformation.The growth of pre-existing voids was modest, and material damage was dominated by voids that were newly formed during deformation from α′ grains. The initiation and progress of damage were influenced by the combined effects of the γ grain morphology and their interaction with surrounding α′ grains. The complexity of the local morphology governed the martensitic transformation and damage behaviour, and geometrical parameters were identified as highly sensitive indicators for describing this phenomenon. Finally, industrial measures to design damage-resistant TRIP steels based on these research findings are discussed.

Urban metabolic and airway immune profiles increase the risk of infections in early childhood

BackgroundInfections in childhood remain a leading global cause of child mortality and environmental exposures seem crucial. We investigated whether urbanicity at birth was associated with the risk of infections and...

Multiple Mechanisms of Action of Sulfodyne®, a Natural Antioxidant, against Pathogenic Effects of SARS-CoV-2 Infection.

Few therapeutic options are available to treat COVID-19. The KEAP1/NRF2 pathway, the major redox-responsive pathway, has emerged as a potential therapeutic target for COVID-19 as it regulates redox homeostasis and inflammation that are altered during SARS-CoV-2 infection. Here, we characterized the effects of NRF2-agonist Sulfodyne®, a stabilized natural Sulforaphane, in cellular and animal models of SARS-CoV-2 infection. In pulmonary or colonic epithelial cell lines, Sulfodyne® elicited a more efficient inhibition of SARS-CoV-2 replication than NRF2-agonists DMF and CDDO. This antiviral activity was not dependent on NRF2 but was associated with the regulation of several metabolic pathways, including the inhibition of ER stress and mTOR signaling, which are activated during SARS-CoV-2 infection. Sulfodyne® also decreased SARS-CoV-2 mediated inflammatory responses by inhibiting the delayed induction of IFNB1 and type I IFN-stimulated genes in infected epithelial cell lines and by reducing the activation of human by-stander monocytes recruited after SARS-CoV-2 infection. In K18-hACE2 mice infected with SARS-CoV-2, Sulfodyne® treatment reduced both early lung viral load and disease severity by fine-tuning IFN-beta levels. Altogether, these results provide evidence for multiple mechanisms that underlie the antiviral and anti-inflammatory activities of Sulfodyne® and pinpoint Sulfodyne® as a potent therapeutic agent against pathogenic effects of SARS-CoV-2 infection.

Sports injuries of the knee joint. Prevention and rehabilitation

Knee joint injuries are the most common in lower limb injuries and pose the greatest challenge in terms of rehabilitation because of their highly variable specificity, usually related to sporting activities or domestic conditions of injury. The absence of adequate gradual rehabilitation, taking into account potential deviations in the functioning of the damaged joint, will not give a positive result. Thus, there is a need to develop an individual methodology and scheme for further training for each athlete, since too early and insufficient loads can lead to negative consequences in the form of synovitis and increasing pain in the joint. At the same time, insufficient loads greatly increase the rehabilitation time. The inclusion of the latest research in combination with current clinical data ensures the development and implementation of strategies for patient management, improvement of the quality of diagnosis and treatment, and rehabilitation of patients with sports injuries.

Rehabilitation and Return to Sports after Achilles Tendon Repair.

Rehabilitation protocols post-Achilles tendon repair vary widely, particularly regarding weight bearing (WB) and immobilization duration, impacting recovery trajectories significantly. This commentary focuses on rehabilitation strategies following acute Achilles tendon repair (ATR), emphasizing early mobilization and progressive loading. Techniques such as blood flow restriction training (BFRT) and progressive loading to restore strength and tendon mechanical properties are discussed in the context of optimizing recovery, minimizing tendon elongation and facilitating safe return to sport (RTS). This manuscript highlights current evidence and clinical insights to guide practitioners in optimizing rehabilitation protocols for athletes recovering from ATR, aiming to improve functional outcomes and support safe return to athletic activity.

Association between HIV and cytomegalovirus and neurocognitive outcomes among children with HIV.

Children with HIV may experience adverse neurocognitive outcomes despite antiretroviral therapy (ART). Cytomegalovirus (CMV) is common in children with HIV. Among children on ART, we examined the influences of early HIV viral load (VL) and CMV DNA on neurocognition. We determined the association between pre-ART VL, cumulative VL, and CMV viremia and neurocognition using data from a cohort study. Children who initiated ART before 12 months of age were enrolled from 2007-2010 in Nairobi, Kenya. Blood was collected at enrollment and every 6 months thereafter. Four neurocognitive assessments with 12 domains were conducted when children were a median age of 7 years. Primary outcomes included cognitive ability, executive function, attention, and motor. Generalized linear models were used to determine associations between HIV VL (pre-ART and cumulative; N = 38) and peak CMV DNA (by 24 months of age; N = 20) and neurocognitive outcomes. In adjusted models, higher peak CMV viremia by 24 months of age was associated with lower cognitive ability and motor z-scores. Higher pre-ART HIV VL was associated with lower executive function z-scores. Among secondary outcomes, higher pre-ART VL was associated with lower mean nonverbal and metacognition z-scores. Higher pre-ART VL and CMV DNA in infancy were associated with lower executive function, nonverbal and metacognition scores and cognitive ability scores in childhood, respectively. These findings suggest long-term benefits of early HIV viral suppression and CMV control on neurocognition.

Temperature-dependent acoustic emission characteristics and statistical constitutive model of granite under uniaxial compression

Understanding the temperature-dependent mechanical behavior and fracture characteristics of granite is crucial for many engineering projects. In this study, the real-time temperature curves of granite specimens were obtained during the heating and cooling process, and the thermal treatment tests were conducted. The physical properties of the specimen before and after thermal treatment, including mass, volume, and P-wave velocity, were measured. The acoustic emission (AE) signal in the uniaxial compression is monitored. The results indicate that the physical properties of granite deteriorate with temperature, while the mechanical properties show two effects of thermal strengthening and thermal weakening. This phenomenon is comprehensively analyzed by literature statistical data and optical microscopic observation. Furthermore, the AE characteristic is strongly dependent on temperature. High temperature induces more AE ring count to appear in the early stage of loading. As the temperature increases, the crack initiation stress decreases and the table crack propagation stage becomes longer. The attenuation of high-frequency signals and the enhancement of low-frequency signals are related to the development and interaction mechanism of thermally-induced crack and stress-induced crack. At 600 °C, the global b-value increases significantly. Meanwhile, the evolution of dynamic b-value helps explain the failure process of granite under axial load after thermal treatment. In addition, a new thermo-mechanical damage statistical constitutive model of granite considering temperature effects is proposed by introducing AE parameters. The main advantages of this model can well fit the nonlinear behavior of granite in the early loading stage after thermal treatment, and reflect the failure process of granite before the peak value.

COMPARATIVE EVALUATION OF PERI-IMPLANT TISSUES AROUND EARLY LOADED VERSUS DELAYED LOADEDIMPLANTS

Aims and Objectives: This study compared and evaluated the peri-implant tissue alterations in single-piece implants that were loaded early versus delayed. To evaluate the differences in radiographic results and clinical characteristics between early and delayed loaded implants. Materials and Methods: Using radio visio graphs (RVGs), the current study aims to assess and compare the clinical and radiographic results of early loaded implants versus delayed loaded implants. Twenty sites in all, based on the kind of implant loading techniques, were randomly divided into two groups by flipping a coin, following the first screening and the patients who met the inclusion requirements. Ten sites with an early loading technique (GROUP 1) and ten sites with a delayed loading methodology (GROUP 2) were separated into two groups. In both groups, the Bioline single-piece implants were utilised. Results: The clinical parameters probing pocket depth, clinical attachment level, and width of the keratinized peri-implant mucosa were measured at baseline, 3 & 6 months. Changes in marginal bone loss were measured using RVG. To evaluate the alterations in marginal bone level, AUTO CAD was utilised. SPSS V.23 was employed for the purpose of data analysis. Using the Mann Whitney U test for intergroup comparison and Friedmans Two-way ANOVA for intragroup comparison, groups 1 and 2 were assessed on mesial and distal surfaces. Conclusion: Given the current studys constraints, the findings can be summed up as follows: early loaded implants performed better than delayed loaded implants in all clinical and radiographic measures from baseline to six months.

Seasonal Muscular Power Changes: Considerations of Concurrent Resistance and Field-Based Training in Professional Rugby League.

Redman, KJ, Wade, L, Whitley, R, Connick, MJ, Kelly, VG, and Beckman, EM. Seasonal muscular power changes: considerations of concurrent resistance and field-based training in professional rugby league. J Strength Cond Res 38(9): 1620-1626, 2024-A rugby league player's ability to develop or maintain lower-body power will be significantly influenced by the resistance and field-based training loads completed. This study aimed to examine the power changes across a rugby league season and to investigate the relationship of concurrent training and training experience on power changes. Eighteen rugby league players participated in this study. Lower-body power was evaluated using a countermovement jump throughout the season. Four measures of external training loads were collected. A Friedman's test was used to assess differences in power throughout different phases of the season. A series of Spearman's rank-order correlations were conducted to assess the relationship between percentage changes in power during the training block, external training loads, and training experience. Countermovement jump peak velocity significantly decreased from the start ( p = 0.006) and end of pre-season ( p = 0.022) to the late competition. Correlation analysis revealed a large significant association between early competition field-based external loads (relative ( rs = -0.571) and total distance ( rs = -0.628)) and change in peak power. Very large significant negative relationships were also observed between mid-competition volume load with change in peak force ( rs = -0.825) and peak power ( rs = -0.736). Training experience was not significantly associated with changes in muscular power variables throughout this study. Coaches should seek to monitor changes in peak power when competition begins and to assist with decision-making for potential adjustments to running volume and intensity during field-based sessions.

Shorten τ<sub>1</sub> in Chronic Early vs. Late Systolic LV Load for Systolic Dysfunction in Ascending vs. Descending Thoracic Aortic Stenosis

<i>Background:</i> Arterial hypertension (HTA) results with diastolic LV dysfunction (DD), important to develop systolic LV dysfunction and exercise intolerance with HF. Separating between chronic late (LL) to early LV load (EL) during systole, impaired LV relaxation is present earlier in chronic LL vs. EL, having early HF, as result of myocardial ischemia and systolic LV dysfunction in HTA. <i>Objective and Methods:</i> to assess early systolic in diastolic LV dysfunction from biexponential τ regression assessment, using single beat and mono-exponential regression analysis, with nonzero asymptote with special software in LL and EL, between 4<sup>th</sup> and 8<sup>th</sup> week in a porcine model. This assesses early HF and systolic LV pump dysfunction, from fast_τ (τ<sub>1</sub>), for early systolic LV dysfunction, in LVH remodeling in moderate LV afterload increase. Fourteen domestic male pigs, underwent LV pressure measurements with conductance Millar 5F catheter having moderate ascending aortic banding (EL=6), and in descending thoracic aortic stenosis, as in hypertension (LL=8). τ<sub>1</sub> (τ_fast) and τ<sub>2</sub> (for τ_slow) component of bi-exponential τ analyzed LV dysfunction at 4<sup>th</sup> vs. 8<sup>th</sup> week. Under reduced LV load (m3), during ventilation preserved (m1) or suspended transitionally (m2), fast τ assess early systolic dysfunction in LL vs. EL. Associated murmurs were assessed to detect LV valves dysfunction. Data was compared statistically, using two-way repeated measurement ANOVA, after Leven normality test. Results are means±SEM or medians (quartiles), for significant p<0.05. <i>Results:</i> mono-exponential τ was not different, neither changed in LL vs. EL at 4<sup>th</sup> and 8<sup>th</sup> week in m1, m2 or m3, that reduced in both groups with mechanical LV load reduction at 4<sup>th</sup> and 8<sup>th</sup> week (p<0.05). Prolonged bi-exponential asynchronous τ<sub>2</sub>/τ<sub>1</sub> ratio in EL was different from LL at 8<sup>th</sup> week, resulted from LV afterload (τ<sub>2</sub>τ<sub>1</sub> interaction p<0.05). τ_fast was different, being shorten in EL vs. LL at 4<sup>th</sup> and 8<sup>th</sup> week. Reduced bi-exponential τ<sub>2</sub>τ<sub>1</sub> ratio in EL and increased in LL, with mechanical load reduction, improved LV ischemia with DD in EL at 4<sup>th</sup> and 8<sup>th</sup> week of moderate LV afterload increase, but did not respond in LL. There was predominant systolic murmur in EL and diastolic murmur in LL, pronounced with load reduction. <i>Conclusion:</i> Prolonged bi-exponential τ<sub>1</sub> in LL shows early systolic LV dysfunction within DD. LV ischemia and systolic with diastolic LV pump dysfunction in EL presents shorten fast_τ, being unresponsive to mechanical LV load reduction in LL.

The Mineral Apposition Rate on Implants with Either a Sandblasted Acid-Etched Implant Surface (SLA) or a Nanostructured Calcium-Incorporated Surface (XPEED®): A Histological Split-Mouth, Randomized Case/Control Human Study.

This study aimed to histologically evaluate the effects of XPEED® and SLA surface on the mineral apposition rate (MAR) at 3 and 5 weeks in titanium dental implants placed in human bone. In total, 17 titanium dental implants with XPEED® surface (n = 9) used as test and SLA surface (n = 8) used as control were included in this study. Each patient received four doses of tetracycline 500 mg at 12 h intervals 2 weeks prior to biopsy retrieval. Implant retrieval was performed, and retrieved biopsies were carefully treated for histomorphometric evaluation under epifluorescence microscopy. At 3 and 5 weeks, newly formed bone appeared in direct contact with both types of tested surfaces. At 3 weeks, the MAR value was, respectively, 2.0 (±0.18) μm/day for XPEED® implants and 1.5 (±0.10) μm/day for SLA implants (p = 0.017). At 5 weeks, lower MAR values for both XPEED® and SLA implants were noted, with 1.2 (±0.10) μm/day and 1.1 (±0.10) μm/day, respectively (p = 0.046). The overall evaluation by linear regression analysis for both time and implant surfaces showed a decreased osteoblast activity at 5 weeks compared to 3 weeks (p < 0.005). The results of the present study show that the bone apposition rate occurs faster around implants with XPEED® surface at 3 weeks and 5 weeks of healing. MAR values may support the use of implants with XPEED® surfaces in early loading protocols.

Lok-Test and Capo-Test pullout for in-situ concrete strength

Among the test systems for in-place concrete strength available today, two measure the in-place physical strength, pullout, and cores. Both systems are dealt with in detail in this paper, the pullout systems named LOK-TEST/CAPO-TEST (ASTM C900-19) and coring (ASTM C42/42M-18). Testing in-situ with accurate test systems will reveal effects on the final strength from a potential mix’s over transportation, pumping, consolidation, compaction, and curing. With the LOK-TEST system testing of the pre-installed inserts takes 4–5 minutes each, easily and with only one small suitcase brought along. The CAPO-TEST, originally designed to supplement the LOK-TEST, takes 15–20 minutes for each test to be performed anywhere on a structure without pre-installed inserts. No large holes are left in the structure from coring and thinner elements may be tested without weakening them structurally. The pullout test provides accurately the In-Place Strength without testing cores and the duration is about 15 minutes compared to 3–4 days for coring correctly cured. General robust correlations to strength of standard specimens exist no matter what parameter is considered for normal concrete, even for carbonation of the surface layer. With the systems the cover layer protecting the reinforcement may be checked efficiently and quickly, not at least in areas with dense reinforcement or on slim structures. Bad curing conditions are revealed and the consequences in terms of reduced service life for presence of chlorides or carbonation may be estimated swiftly. This paper is benchmarking 50 years of successful in-situ concrete strength measurements, from studies of the failure mechanism and laboratory/on-site correlations to full scale testing of structures in Europe, Scandinavia, and Canada. Six testing cases with emphasis on pullout and cores are illustrating different applications: Case 1. Production testing at the Great Belt Link, Denmark. Case 2. Service life of bridge pier, Great Belt Link, Denmark. Case 3. Curing of the cover layer evaluated by pullout and conductivity, Denmark. Case 4. Strength testing with CAPO-TEST for further loading of old bridges, Poland. Case 5. In-Situ compressive strength testing of quarantined precast concrete tunnel lining segments using CAPO-TEST, UK. Case 6. Safe and early loading with LOK-TEST, Canada. Other cases are given on www.NDTitans.com

Study on the Tensile Failure Characteristics and Energy Calculation Model of Coal Seam Hard Roof Considering the Mining Speed

To reveal the influence mechanism of mining speed on roof fracture-type rockburst, the Brazilian split technique combined with acoustic emission monitoring technology was employed to study the effects of loading rates on the tensile failure characteristics and acoustic emission parameters of coal series sandstone. The linear relationship between the tensile strength of the samples and the change rate of tensile stress was determined. The mining speed was introduced into the mechanical model of initial and cyclic fracture of the hard roof, and the quantitative relationship between the maximum rate of change of tensile stress within the hard roof and the mining speed was derived. Based on this, a computational model for the bending elastic energy of the hard roof during initial and cyclic fractures, considering the mining speed, was established. The main findings are as follows: As the loading rate increases, the distribution range of acoustic emission energy in sandstone Brazilian split samples before failure widens, with a significant rise in acoustic emission ring-down counts and energy at failure. At lower loading rates, acoustic emission events primarily occur near sample failure, whereas at higher rates, they mostly happen in the early loading stage. The higher the mining speed, the less opportunity there is for internal micro-fractures to develop and expand before the hard roof fractures, which macroscopically results in increased tensile strength and a larger amount of energy released at the moment of fracture. Bending elastic energy rises approximately linearly with mining speed, and the thicker the hard roof, the more sensitive the bending elastic energy is to changes in mining speed. This effect is even more pronounced during cyclic fractures. Optimizing mining speed is crucial for preventing roof fracture-type rockbursts, especially in mining workfaces with thick and hard roofs.

IMPACTION BONE GRAFTING OF LARGE DEFECTS IN ANKLE AND HINDFOOT FUSIONS

BackgroundAnkle and hindfoot fusion in the presence of large bony defects represents a challenging problem. Treatment options include acute shortening and fusion or void filling with metal cages or structural allograft, which both have historically low union rates. Impaction grafting is an alternative option.MethodsA 2 centre retrospective review of consecutive series of 32 patients undergoing hindfoot fusions with impaction bone grafting of morselised femoral head allograft to fill large bony void defects was performed. Union was assessed clinically and with either plain radiography or weightbearing CT scanning. Indications included failed total ankle replacement (24 patients), talar osteonecrosis (6 patients) and fracture non-union (2 patients). Mean depth of the defect was 29 ±10.7 mm and mean maximal cross-sectional area was 15.9 ±5.8 cm2. Tibiotalocalcaneal (TTC) arthrodesis was performed in 24 patients, ankle arthrodesis in 7 patients and triple arthrodesis in 1 patient.ResultsMean age was 57 years (19–76 years). Mean follow-up of 22.8 ±8.3 months. 22% were smokers. There were 4 tibiotalar non-unions (12.5%), two of which were symptomatic. 10 TTC arthrodesis patients united at the tibiotalar joint but not at the subtalar joint (31.3%), but only two of these were symptomatic. The combined symptomatic non-union rate was 12.5%. Mean time to union was 9.6 ±5.9 months. One subtalar non-union patient underwent re-operation at 78 months post-operatively after failure of metalwork. Two (13%) patients developed a stress fracture above the metalwork that healed with non-operative measures. There was no bone graft collapse with all patients maintaining bone length.ConclusionImpaction of morselised femoral head allograft can be used to fill large bony voids around the ankle and hindfoot when undertaking arthrodesis, with rapid graft incorporation and no graft collapse despite early loading. This technique offers satisfactory union outcomes without the need for shortening or synthetic cages.

Long-Term Outcomes of a Percutaneous Wide-Diameter Bone-Anchored Hearing Implant: A Clinical Evaluation of More than 800 Implants.

This study evaluates the clinical outcomes of 807 percutaneous wide-diameter bone-anchored hearing implants (BAHIs) in 701 patients. In addition, it compares patient groups and examines bone conduction device (BCD) usage. Retrospective cohort study. Mean follow-up period of 3.8 years. Tertiary referral center. All patients implanted with a percutaneous wide-diameter BAHI until December 2020 were included. Patients were divided into age groups, "loading-time" groups, and, if applicable, specific subgroups thought to be at risk for complications postsurgery, e.g., intellectual disability and comorbidities. Soft tissue reaction, implant survival, revision surgery, and BCD usage. In 9.1% of the 5,188 observations of 807 implants, an adverse soft tissue reaction was reported according to the Holgers' scale. Significantly more (adverse) soft tissue reactions were observed in children and intellectually disabled (ID) patients (p < 0.05). Comorbidity subgroups showed no significant differences in soft tissue reactions. Implant loss percentage, including explantations, was 6.2%. Implant survival was significantly worse in patients with ID (14.1%; p = 0.021). Pediatric age, early loading, or comorbidities did not significantly influence implant survival. At least 592 implants (73.4%) were used for bone conduction hearing, of which 65.4% were used daily. Both children and ID patients are more prone to (adverse) soft tissue reactions, ID patients only have a higher risk of implant loss. The rate of implant loss in children seemed to be reduced compared to previous studies and thus more comparable to adults since using wide-diameter implants.

Adding mechanobiological cell features to finite element analysis of an immediately loaded dental implant.

Finite element analysis (FEA) has been used to analyze the behavior of dental materials, mainly in implantology. However, FEA is a mechanical analysis and few studies have tried to simulate the biological characteristics of the healing process of loaded implants. This study used the rule of mixtures to simulate the biological healing process of immediate implants in an alveolus socket and bone-implant junction interface through FEA. Three-dimensional geometric models of the structures were obtained, and material properties were derived from the literature. The rule of mixtures was used to simulate the healing periods-immediate and early loading, in which the concentration of each cell type, based on in vivo studies, influenced the final elastic moduli. A 100 N occlusal load was simulated in axial and oblique directions. The models were evaluated for maximum and minimum principal strains, and the bone overload was assessed through Frost's mechanostat. There was a higher strain concentration in the healing regions and cortical bone tissue near the cervical portion. The bone overload was higher in the immediate load condition. The method used in this study may help to simulate the biological healing process and could be useful to relate FEA results to clinical practice.