Application of a Custom-designed External Fixation Restorer for Pediatric Femoral Fractures

Background: Closed reduction of pediatric femoral shaft fractures is one of the most difficult types of partial fracture reductions. Open reduction increases the harm to children. Although smaller invasive open reduction is mostly used at present, it has an impact on the microenvironment around the fracture and results in increased intraoperative bleeding, an increased risk of postoperative infection and surgical scarring, which has a great psychological impact on children. Methods: Given the above challenges, we propose another intraoperative reduction method. The technique described involves closed reduction and internal fixation for pediatric femoral shaft fractures using a new type of intraoperative fixator. Result: This technique brings hope that the success rate of closed reduction for pediatric femoral shaft fractures can reach 100%. Conclution: The method is demonstrated in a patient.

Thermal and Mechanical Assessment of PLA-SEBS and PLA-SEBS-CNT Biopolymer Blends for 3D Printing

Polylactic acid (PLA) is one of the most promising biopolymers often used as a raw material in 3D printing in many industrial areas. It has good mechanical properties, is characterized by high strength and stiffness, but unfortunately, it has some disadvantages; one is brittleness, and the other is slow crystallization. Amounts of 1–5% SEBS (styrene-ethylene-butylene-styrene) thermoplastic elastomer were blended into the PLA and the thermal and mechanical properties were investigated. DSC (Differential Scanning Calorimetry) measurements on the filaments have shown that SEBS increases the initial temperature of crystallization, thereby acting as a nucleating agent. The cooling rate of 3D printing, on the other hand, is too fast for PLA, so printed specimens behave almost amorphously. The presence of SEBS increases the impact strength, neck formation appears during the tensile test, and in the bending test, the mixture either suffers partial fracture or only bends without fracture. Samples containing 1% SEBS were selected for further analysis, mixed with 0.06 and 0.1% carbon nanotubes (CNTs), and tested for thermal and mechanical properties. As a result of CNTs, another peak appeared on the DSC curve in addition to the original single-peak crystallization, and the specimens previously completely broken in the mechanical tests suffered partial fractures, and the partially fractured pieces almost completely regained their original shape at the end of the test.

Experimental Study on Triaxial Unloading Failure of Deep Composite Coal-Rock

With the deep mining of coal, the phenomenon of high ground stress is more likely to cause dynamic disaster. In view of the above problems, this paper takes the unloading process of coal mining as the background to study the effects of mining rates under different conditions on the mechanical properties and triaxial failure criterion of composite coal-rock, so as to provide a theoretical basis for the prevention and control of dynamic disasters in coal mines. The composite coal-rock models with a composite ratio of 1 : 1 : 1 were tested under different unloading rates or confining pressures. The results show that the triaxial unloading process of coal-rock can be divided into five stages: compaction, single elasticity, elastic-plastic unloading, partial fracture, and complete fracture. In this paper, the failure criterion of composite coal-rock triaxial unloading is derived. The unloading rate has an exponential relationship with the triaxial compressive strength, and the relationship between initial confining pressure and compressive strength is linear. The triaxial compressive strength is determined by both. The peak strains ε of all samples under different unloading conditions were around 0.01. And initial confining pressure had an influence on the strain variation trend during the unloading of composite coal-rock. The higher the initial confining pressure, the greater the elastic modulus. In addition, an increase of initial confining pressure led to the increase of the total energy converted into dissipated part in the process of fracture and caused the obvious increase of the rebound characteristics of the curve. However, the unloading rate had no influence on the strain trend.

Depth-dependent Clustering Analysis of Fractures in Crystalline Basement Rocks

<p>Understanding the complex seismic, thermal, hydraulic and mechanical processes active during the hydraulic stimulation or continuous operation of Enhanced Geothermal Systems (EGS) requires an accurate description of the pre-existing fractures and faults. However, the three-dimensional characterization of the fracture network is challenging, as direct observation of the discontinuity network at great depth is limited. Fracture image logs and continuous core, which provide line samples through the fracture network, are most valuable in this regard as they provide the most precise option to place constraints on network attributes in stochastic realizations of the fractured rock mass. Among various geometrical attributes, the spatial clustering of fractures plays a critical role on the rock mass properties. </p><p>Here, we analyzed the spatial distribution of fractures derived from image log runs in six deep boreholes in crystalline basement rock. In one well, the fracture distribution from continuous core was also available. The wells were drilled to depths between 2-5 km, and were all located in the same tectonic setting of the Upper Rhine Graben, which is recognized for its high geothermal potential. The normalized correlation integral method was employed to define the scaling relationships of fracture patterns. This methodology is demonstrated to be less affected by the finite size effects, delivering reliable estimates of scaling laws.</p><p>Detailed analyses of image log datasets revealed fractal scaling with similar fractal dimensions (between 0.85 and 0.96), prevailed over almost two orders of magnitude of scale. The same was true for the fracture distribution derived from the continuous core, although this distribution was found to be more clustered than that derived from image logs in the same well (i.e. the fractal dimension was lower, which may be due to the partial fracture sampling of image logs which have a coarser resolution than continuous core analyses). Analysis of fractures in sub-sections of the core dataset from progressively increasing depths revealed no systematic depth-dependency for the fractal dimension, although a local variation at a scale of hundreds of meters was identified.</p>

Subcutaneous Implantable Cardioverter Defibrillator (S-ICD) Electrode Fracture: Follow-up, Troubleshooting and Evaluation

Introduction: The subcutaneous-ICD (S-ICD) and its electrode were developed to avoid long-term complications of transvenous leads in the vasculature. Methods: We report a case of unexpected, inappropriate S-ICD shocks due to oversensing of high amplitude, non-physiologic, electrical noise artifacts that were not preceded by high impedance alerts or sensing electrogram noise detections. Results: Following explant, high-magnification, X-ray imaging of the S-ICD electrode demonstrated partial fracture of the distal sensing conductor located near a short radius bend in the electrode at the electrode-header interface. Conclusions: Clinicians should be aware of a potential for fatigue failure fracture of the S-ICD electrode. Recommendations for systematic S-ICD follow-up and troubleshooting are discussed.

Histological Observation Related to the Use of Laser and Ultrasound on Bone Fracture Healing

Objective: To study the effect of both laser and ultrasound radiation on bone fracture healing process. Materials and Methods: Nd:YAG laser (1064 nm wavelength, 135 mW power, 16 joules energy) and ultrasound (1 MHz frequency, 50 mW/cm2 power intensity) were used in this work. Fifteen mature, male, albino rats, were divided into three groups and subjected to a partial fracture on the lateral aspect of femur by a sharp blade. The fi rst group of these animals served as control group. The second group was illuminated by the Nd:YAG laser for two minutes; the fi rst dose was given immediately after surgical fracture induction; the other doses were given on days two, three, six and then one dose weekly for the next three weeks while the third group were treated by the addition of the CW ultrasound perpendicular to the laser treatment in the second group. Results: The present study showed that ultrasound increases the penetration of laser power through the tissue. The histological assessments at day 28 after the fracture of fi rst group showed incomplete healing of the bone with disfi guration and disarrangement of Haversian system and the periosteum was not yet well developed. Treatment with laser showed irregularity and lack of Haversian system formation in bone healing of the second group. The laser and ultrasound treated group (third group) expressed a complete healing at the site of fracture with a complete layer of periosteum and a well arranged Haversian system. Conclusion: Combination of laser and ultrasound in therapy can enhance healing process of a fractured bone more than laser therapy alone, as ultrasound increases the depth of laser penetration in tissue.

Partial Fracture of a Subcutaneous ICD Lead from Mechanical Trauma

Transvenous implantable cardioverter-defibrillators (TV-ICD) have electrode failure rates as high as 20% over a 10 year followup with 12% as a result of lead fractures. [1] The development of the Boston Scientific subcutaneous ICD (S-ICD) promoted the benefit of significantly reduced post-implant complication rates. [4] We present the first reported case of a S-ICD electrode failure secondary to partial fracture as a result of mechanical trauma.

Features of the progressive destruction of bridge structures

The problem of safe maintenance of bridge structures in the event of emergency impacts is being considered. Also the problem of accounting for beyond-design-basis impacts on them is being discussed. Particular attention is paid to the problem of progressive fracture of bridges, which is practically not studied in our country. The equivalence of the problems of progressive fracture and survivability of engineering structures is discussed. An overview is given of a number of publications on bridge construction accidents with an analysis of the causes, which are divided into three groups: those caused by catastrophic natural events (60 per cent), caused by design errors and construction defects (30 per cent) and also caused by poor maintenance or excessive load (10 %). A.V. Perelmuter’s five theses on progressive fracture are being formulated: (1) The appearance of local failures of the designed system is quite possible; (2) The process of developing sequential destruction is the most dangerous of all possible; (3) Protection against progressive collapse is possible not only by bearing structures strength reservation of the construction, but on the basis of an analysis of the genesis of emergencies it is possible to propose other safety methods against progressive collapse; (4) When modelling the processes of progressive fracture, dynamic effects accompanying the removal of individual elements from the system should be taken into account; (5) If progressive fracture is unavoidable, ways should be sought to localize it and reduce its effects. At the end of the article, examples of progressive fracture of bridge structures due to the loss of sustaining capacity by the main members (due to corrosion cracking of the reinforcement) and owing to the partial fracture of some load-bearing elements of bridge superstructures are given. A conclusion is made on the need to organize scientific research on the progressive fracture of bridge structures.

Characterization of the Biological Fingerprint and Identification of Associated Parameters in Stress Fractures by FTIR Spectroscopy

Introduction. The stress fractures (SFs) are a common condition in athletes and military recruits, characterized by partial fracture caused by repetitive applications of stresses that are lower than the stress required to fracture the bone in a single loading. Fourier transform infrared (FTIR) spectroscopy gives information about the bone composition and also can determine the amount of a molecule. For this reason, the FTIR spectroscopy may be used as a tool for diagnosis of certain bone diseases related to the bone strength. In this research, we established the contributions of mineral and collagen properties to SF risk through FTIR spectroscopy, analyzing the biochemical profile differences between the healthy bone and the bone with an SF. Materials and Methods. Previous written informed consent was obtained, and samples of the hip with an SF (n = 11) and healthy bone from the femur with traumatic fracture (n = 5) were obtained and analyzed employing FTIR spectroscopy and its biochemical mapping function. Then, using FTIR spectra and the map, the collagen content and ratios corresponding to matrix maturity, mineralization, carbonate substitution, acid phosphate substitution, and crystallinity were calculated. Moreover, a histopathological analysis through Masson’s staining was conducted. Results. The biochemical analysis showed that the bone with an SF presented a bone immaturity characterized by a higher content of collagen, lower matrix maturity, mineralization, carbonate and acid phosphate substitutions, and greater crystallinity compared to the healthy bone, being checked by the ratio analysis and biochemical mapping. Besides, Masson’s stain showed a higher collagen content in the bone with an SF. Conclusions. The bone with an SF presented alterations in its biochemical composition, showing bone immaturity, which broadens the panorama of the condition to investigate future treatments or prophylactic techniques.