Continuous Bridging Research Articles

A continuous interfacial bridging approach to fabricate ultrastrong hydroxylated carbon nanotubes intercalated MXene films with superior electromagnetic interference shielding and thermal dissipating properties

A continuous interfacial bridging approach to fabricate ultrastrong hydroxylated carbon nanotubes intercalated MXene films with superior electromagnetic interference shielding and thermal dissipating properties

EVALUATION OF A CALCIUM PHOSPHATE-COLLAGEN MATRIX BONE GRAFT WITH NEEDLE-SHAPED SUBMICRON SURFACE TOPOGRAPHY IN A CLINICALLY RELEVANT SHEEP POSTEROLATERAL LUMBAR SPINE FUSION MODEL

Biphasic calcium phosphate (BCP) with a characteristic needle-shaped submicron surface topography (MagnetOs) has attracted much attention due to its unique bone-forming ability which is essential for repairing critical-size bone defects such as those found in the posterolateral spine. Previous in vitro and ex-vivo data performed by van Dijk LA and Yuan H demonstrated that these specific surface characteristics drive a favorable response from the innate immune system.This study aimed to evaluate and compare the in vivo performance of three commercially-available synthetic bone grafts, (1) i-FACTOR Putty®, (2) OssDsign® Catalyst Putty and (3) FIBERGRAFT® BG Matrix, with that of a novel synthetic bone graft in a clinically-relevant instrumented sheep posterolateral lumbar spine fusion (PLF) model. The novel synthetic bone graft comprised of BCP granules with a needle-shaped submicron surface topography (MagnetOs) embedded in a highly porous and fibrillar collagen matrix (MagnetOs Flex Matrix).Four synthetic bone grafts were implanted as standalone in an instrumented sheep PLF model for 12 weeks (n=3 bilateral levels per group; levels L2/3 & L4/5), after which spinal fusion was determined by manual palpation, radiograph and µCT imaging (based on the Lenke scale), range-of-motion mechanical testing, and histological and histomorphological evaluation.Radiographic fusion assessment determined bilateral robust bone bridging (Lenke scale A) in 3/3 levels for MagnetOs Flex Matrix compared to 1/3 for all other groups. For µCT, bilateral fusion (Lenke scale A) was found in 2/3 levels for MagnetOs Flex Matrix, compared to 0/3 for i-FACTOR Putty®, 1/3 for OssDsign® Catalyst Putty and 0/3 for FIBERGRAFT® BG Matrix. Fusion assessment for MagnetOs Flex Matrix was further substantiated by histology which revealed significant graft resorption complemented by abundant bone tissue and continuous bony bridging between vertebral transverse processes resulting in bilateral spinal fusion in 3/3 implants.These results show that MagnetOs Flex Matrix achieved better fusion rates compared to three commercially-available synthetic bone grafts when used as a standalone in a clinically-relevant instrumented sheep PLF model.

Effect of the laser-wire relative position on the wire-based laser-directed energy deposition of in-situ synthesis Ti/TiB/TiC composite coatings

Laser-directed energy deposition (LDED) with a Ti-B4C cored wire was utilized to synthesize the TiB- and TiC-reinforced titanium matrix composite coatings for enhancing the tribological performance of Ti alloys. The wire transfer behaviors, microstructural characteristics and wear performance of the coatings were investigated at two different laser-wire relative positions. The wire deposition better adapted to varying processing parameters when the wire tip was placed in the anterior portion of the laser-irradiated region, which resulted in the continuous bridging transfer mode. This enabled favorable process stability, track formability, and microstructure homogenization. The representative LDEDed coatings were dominated by TiB/TiC composite structures characterized by the embedding of TiC dendrites into TiB hollow prisms. The formation of TiB/TiC composite structures was related with the heterogeneous nucleation on the coherent (010)TiB//(101)TiC interface, of which the two-dimensional lattice mismatch was only 5.500%. A well-defined three-phase orientation relationship between the α-Ti matrix and reinforcements of TiB and TiC was identified as [112¯1]α-Ti//[01¯0]TiB//[101]TiC. This relationship improved interface stability and restrained the interfacial debonding under an imposed load. The typical LDEDed coating produced by the continuous bridging transfer mode possessed the desired combination of high hardness and low wear rate, which was primary attributable to the direct load-bearing effect of the tightly combined TiB/TiC intergrowth structures and the indirect load-sharing effect of the TiBw/TiCp eutectic phases.

Multifunctional wet-adhesive chitosan/acrylic conduit for sutureless repair of peripheral nerve injuries

The incidence of peripheral nerve injury (PNI) is high worldwide, and a poor prognosis is common. Surgical closure and repair of the affected area are crucial to ensure the effective treatment of peripheral nerve injuries. Despite being the standard treatment approach, reliance on sutures to seal the severed nerve ends introduces several limitations and restrictions. This technique is intricate and time-consuming, and the application of threading and punctate sutures may lead to tissue damage and heightened tension concentrations, thus increasing the risk of fixation failure and local inflammation. This study aimed to develop easily implantable chitosan-based peripheral nerve repair conduits that combine acrylic acid and cleavable N-hydroxysuccinimide to reduce nerve damage during repair. In ex vivo tissue adhesion tests, the conduit achieved maximal interfacial toughness of 705 J m−2 ± 30 J m−2, allowing continuous bridging of the severed nerve ends. Adhesive repair significantly reduces local inflammation caused by conventional sutures, and the positive charge of chitosan disrupts the bacterial cell wall and reduces implant-related infections. This promises to open new avenues for sutureless nerve repair and reliable medical implants.

Melting Characteristics of C-Type Filler Metal in GTAW

A C-type filler metal was developed to overcome the low deposition rate (DR) of gas tungsten arc welding (GTAW). The present study investigated the maximum DR for a novel C-type filler metal and compared it to conventional circular welding wires during GTAW using an Alloy 625 filler metal. For comparison with conventional circular welding wires, a ø1.2-mm (0.047-in.) welding wire, which is most widely used in practice, and a ø2.4-mm (0.094-in.) welding wire, which has almost the same sectional area as the novel C-type filler metal, were used in this research. An industrial robot was utilized to produce bead-on-plate welds in the flat position. The results revealed that at the same 200-A welding current, the DR of the C-type filler metal was higher than the conventional circular welding wires by 1.17 to 1.4 times according to the sectional area of the circular welding wires. At a high welding current of 500 A, it was impossible for the ø1.2-mm welding wire to deposit quality welds, and the acceptable range of the DR for the ø2.4-mm welding wire was narrow (i.e., 7–8 kg/h [15.4–17.6 lb/h]). However, the acceptable range of the DR for the C-type filler metal was as broad as 5.04–12.1 kg/h (11.1–26.6 lb/h) under the high welding current of 500 A. The maximum DR of the C-type filler metal was 1.51 times that of the ø2.4-mm welding wire. The mechanism of obtaining a high DR using the C-type filler metal was analyzed from the viewpoint of the continuous bridging transfer at the melting edge of the C-type filler metal. The ability of the C-type filler metal to achieve high DRs at high-current regions was superior to the conventional ø1.2- and ø2.4-mm welding wires.

Update to Management of Acute Scaphoid Fractures.

The scaphoid is the most commonly fractured carpal bone. With high clinical suspicion and negative radiographs, expedient evaluation by CT or MRI has been recommended. When treating nondisplaced or minimally displaced scaphoid waist and distal pole fractures, immobilization below the elbow without inclusion of the thumb is an option. Comparatively, early surgical intervention for nondisplaced or minimally displaced scaphoid waist fractures allows for quicker return of function, but with increased risk of surgical complications and no long-term outcomes differences compared with cast immobilization. For most patients with such fractures, consideration for aggressive conservative treatment involving 6 weeks of immobilization with CT assessment to guide the need for continued casting, surgical intervention, or mobilization is advocated. Determination of union is best done with a CT scan at 6 weeks and at least 50% continuous trabecular bridging across the fracture site deemed sufficient to begin mobilization. Nonsurgical and surgical management of scaphoid fractures requires a thorough understanding of fracture location, fracture characteristics, and patient-specific factors to provide the best healing opportunity of this notoriously difficult fracture and return the patient to full function.

Numerical modeling of near-wellbore diverter bridging in hydraulic fracturing

In this work, we used a particle transport model integrated into the fluid solver in FLAC to simulate the transport of particles in the near-wellbore region inside a hydraulic fracture. Complex flow behaviors, including divergent flow near the fracture entrance and detouring flow around diverter packs, can be captured in this coupling system. In the numerical implementation, the coupled fluid flow and particle transport are realized by updating the fracture permeability, particle concentration, and velocities of fluid and particles in each time step. Simulation results indicate that the final shape of the particle bridging zone at the near-wellbore region is determined by the flow-driven and settling-driven particle transport. A continuous bridging band initially forms at the bottom region of the fracture, then the fluid-driven particles move upwards to block the top region of the fracture. Lastly, a V-shaped bridging band is formed inside the fracture. It is observed that high initial particle concentration and large particle size result in the creation of a small-scale bridging band near the injection entrance, which promotes the rapid growth of the closed bridging band and high-pressure buildup.

Creation and preclinical evaluation of a novel mussel-inspired, biomimetic, bioactive bone graft scaffold: direct comparison with Infuse bone graft using a rat model of spinal fusion.

Infuse bone graft is a widely used osteoinductive adjuvant; however, the simple collagen sponge scaffold used in the implant has minimal inherent osteoinductive properties and poorly controls the delivery of the adsorbed recombinant human bone morphogenetic protein-2 (rhBMP-2). In this study, the authors sought to create a novel bone graft substitute material that overcomes the limitations of Infuse and compare the ability of this material with that of Infuse to facilitate union following spine surgery in a clinically translatable rat model of spinal fusion. The authors created a polydopamine (PDA)-infused, porous, homogeneously dispersed solid mixture of extracellular matrix and calcium phosphates (BioMim-PDA) and then compared the efficacy of this material directly with Infuse in the setting of different concentrations of rhBMP-2 using a rat model of spinal fusion. Sixty male Sprague Dawley rats were randomly assigned to each of six equal groups: 1) collagen + 0.2 µg rhBMP-2/side, 2) BioMim-PDA + 0.2 µg rhBMP-2/side, 3) collagen + 2.0 µg rhBMP-2/side, 4) BioMim-PDA + 2.0 μg rhBMP-2/side, 5) collagen + 20 µg rhBMP-2/side, and 6) BioMim-PDA + 20 µg rhBMP-2/side. All animals underwent posterolateral intertransverse process fusion at L4-5 using the assigned bone graft. Animals were euthanized 8 weeks postoperatively, and their lumbar spines were analyzed via microcomputed tomography (µCT) and histology. Spinal fusion was defined as continuous bridging bone bilaterally across the fusion site evaluated via µCT. The fusion rate was 100% in all groups except group 1 (70%) and group 4 (90%). Use of BioMim-PDA with 0.2 µg rhBMP-2 led to significantly greater results for bone volume (BV), percentage BV, and trabecular number, as well as significantly smaller trabecular separation, compared with the use of the collagen sponge with 2.0 µg rhBMP-2. The same results were observed when the use of BioMim-PDA with 2.0 µg rhBMP-2 was compared with the use of the collagen sponge with 20 µg rhBMP-2. Implantation of rhBMP-2-adsorbed BioMim-PDA scaffolds resulted in BV and bone quality superior to that afforded by treatment with rhBMP-2 concentrations 10-fold higher implanted on a conventional collagen sponge. Using BioMim-PDA (vs a collagen sponge) for rhBMP-2 delivery could significantly lower the amount of rhBMP-2 required for successful bone grafting clinically, improving device safety and decreasing costs.

Experimental study on interface failure behavior of 3D printed continuous fiber reinforced composites

Additive manufacturing (or 3D printing) for continuous fiber composite exhibits great potential for fabrication of next-generation lightweight sophisticated structural components. Nevertheless, understanding of interface characteristics of printed parts has remained an open research question for broader applications of this new technology in engineering practice. This study aimed to evaluate the interfacial quality of 3D-printed carbon fiber reinforced plastic (CFRP) composites from two aspects: interlaminar fracture toughness in a pure mode and interfacial failure mechanism in a mixed mode. Prior to the experimental tests, the microstructural quality of the 3D printed specimens was characterized, which showed that the void content and shape of different materials are different. There is a clear boundary line where the short fiber matrix layer and the continuous fiber reinforced layer are in contact, while the interface formed between the same material layers has no evident connection traces. The standard specimens were printed for testing pure mode I and mode II interlaminar fracture toughness, through which the G Ι C and G IIC of interface between continuous carbon fiber layers was characterized. It was found that the fiber bridging phenomenon presented in the double cantilever beam (DCB) experiments, resulting in a higher initial mode I fracture toughness. The end notched flexure (ENF) tests found that the fracture toughness of initial mode II in between the 0° continuous carbon fiber layers was relatively low. The scanning electron microscope (SEM) analysis revealed that the separated surface had only a small area of the matrix being sheared. The single lap specimen printed directly was proposed as a simplified model for simulating complex structural parts subjected to mixed stress of peel and shear. The mechanical responses and failure characteristics of the interfaces composed of different materials and different fiber angles under mixed stress were studied. It is found that each specimen presented some mixed failure modes, and the interface characteristics of different materials and different fiber orientations were completely different. The results gained in-depth understanding on the interfacial properties of 3D printing fiber reinforced structures, thereby providing key data and knowledge for practical applications. • Different layering methods with different interlayer morphology and void shape. • The critical strain energy release rates of type I and typeⅡwere obtained. • Continuous fiber bridging enhances type I fracture toughness. • The shear resistance of the interface between continuous fibers and matrix is very weak. • Reinforcement materials and fiber angles affect the interfacial bond strength and failure.

Characteristics of Gas–Solid Flow in an Intermittent Countercurrent Moving Bed

The calculation equations of pressure drop and solid flow rate are given in an intermittent countercurrent moving bed with multiple optimized structures. The flow fields are investigated by experimental methods under different conditions, e.g., ratio of position of the gas distributor to the bed width (rp = 0.5~1.5), gas superficial velocity (ug = 0~0.1591 m/s), solid outlet diameter (Do = 5~25 mm) and cone angle (α = 0~60°). It is found that when rp ≥ 1.0, the flow field in the bed is little affected by rp. Flow patterns are divided into three modes: continuous discharging, intermittent discharging (synchronous, asynchronous) and particle bridging. During continuous discharging, the calculation formula of the solid flow rate, which is closely related to Do and gas–solid slip velocity vslip, is established by referring to the modified De Jong and Beverloo formulas, and its error ≤ ±12.5%. The pressure drop of the total bed consists of the pressure drops of the granular bed and the solid outlets, which are affected by Do, vslip and α; it is built by referring to the Ergun formula, and its error ≤ ±17.0%. As the solid flow rate and pressure drop influence each other through vslip, an iterative algorithm is proposed to enhance the computation accuracy.

Is Ankle Arthrodesis With an Ilizarov External Fixator an Effective Treatment for Septic Ankle Arthritis? A Study With a Minimum of 6 Years of Follow-up.

Septic ankle arthritis is a devastating clinical problem with a high potential for permanent disability and amputation. Successful treatment of septic ankle arthritis remains a challenge for the surgeon and patient. Ankle arthrodesis combined with radical debridement may be an effective option to eradicate infection and salvage the limb. Although numerous fusion methods have been proposed, there is controversy about the most effective technique. At a minimum follow-up of 6 years after ankle arthrodesis performed using an Ilizarov external fixator, we asked, (1) In what proportion of patients was bony fusion achieved? (2) What complications were observed, and what reoperations were performed in these patients? (3) How much did patient-reported outcomes improve from before surgery to the most recent follow-up in this group? Between April 2010 to March 2015, we treated 59 patients for septic ankle arthritis. Of those, we considered patients who were at least 18 years of age with irreversible destruction of the joint as potentially eligible. During that time period, all patients met the prespecified criteria and were treated with ankle arthrodesis using an Ilizarov external fixator. Two percent (one of 59) of patients were excluded because they died in the second year after surgery for reasons unrelated to the procedure, and another 7% (four of 59) of patients were excluded because they were lost before the minimum study follow-up interval of 6 years. Finally, 92% (54 of 59) of patients were analyzed at a mean follow-up time of 9 ± 1 years. A total of 61% (33 of 54) were men, and they had a mean age of 48 ± 12 years. Forty-six percent (25 of 54) of patients were smokers, and 13% (seven of 54) of patients had Type 2 diabetes mellitus. All patients received radical debridement and primary arthrodesis with an Ilizarov external fixator, followed by antibiotic therapy. Postoperatively, patients were instructed to perform lower extremity functional exercises and external fixator care; weightbearing ambulation as tolerated was encouraged as early as possible. Fusion was assessed with a radiographic review that was performed by an individual who was not involved in the surgical care of these patients. We defined bony fusion as continuous trabeculae and complete cortical bridging in the fusion interface achieved before 9 months; delayed union was defined as fusion achieved by 9 to 12 months; and nonunion was defined as patients in whom fusion was not achieved by 12 months. Complications and reoperations were tallied through a record review that was performed by an individual who was not involved in the surgical care of these patients. We defined complications as any deviation from the expected postoperative course. We used the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, the VAS active pain score, and the SF-12 questionnaire (including the physical component summary [PCS] score and mental component summary [MCS] score) to assess patient-reported outcomes. The minimum clinically important difference (MCID) for the AOFAS score was 30 points of 100, the MCID for the VAS active pain score was 2 points of 10, and the MCID of PCS and MCS scores was 7 points and 9 points, respectively. Primary bony fusion was achieved in 94% (51 of 54) of patients. Delayed union was found in 2% (one of 54) of patients. Nonunion was found in 6% (three of 54); one of these patients underwent autologous bone grafting during revision, and bony fusion was ultimately achieved. Final bony fusion was achieved in 96% (52 of 54) of patients. Recurrent infection was found in 2% (one of 54). The median (range) AOFAS score improved from 28 points (8 to 59) before surgery to 80 points (52 to 86) at the most recent follow-up (median difference 52; p < 0.001). The median (range) VAS active pain score decreased from 8 points (6 to 9) before surgery to 2 points (0 to 5) at the most recent follow-up (median difference -6; p < 0.001). For the Short Form 12-item score, the median (range) PCS score improved from 0 points (0 to 30) before surgery to 70 points (40 to 95) at the most recent follow-up (median difference 70; p < 0.001), and the median (range) MCS score improved from 46 points (21 to 75) before surgery to 75 points (50 to 92) at the most recent follow-up (median difference 29; p < 0.001). Ankle arthrodesis with Ilizarov external fixation might eradicate an infection and restore foot function in patients with septic ankle arthritis. However, patients should be fully informed of the complications related to the external fixator, such as pin-tract infections, recurrent infection, and nonunion. Standardized and professional pin care is important. Additionally, because Ilizarov external fixators can be inconvenient to the patients' daily lives, future studies should explore how psychologic support affects patients who undergo ankle arthrodesis with these devices. Level IV, therapeutic study.

The evolution of multi and hierarchical carbides and their collaborative wear-resisting effects in CoCrNi/WC composite coatings via laser cladding

This study successfully prepares CoCrNi-xWC (x = 0, 5, 15, 25 wt%) composite coatings by laser cladding. The phase composition, microstructure, mechanical properties, and wear resistance of the composite coatings are then analyzed. In particular, the evolution and synergistic effects of the multi and hierarchical carbides derived from the decomposition of the original WC are discussed in detail. The phase composition changes from a single FCC phase to FCC and complex multiple carbide phases of WC-rich carbides + Cr-rich carbides. The microstructures are typical dendritic structures, multi and hierarchical carbides appear in the interdendritic region, and many eutectic carbides begin to emerge. Multiple carbides make up large amounts of clusters, and eutectic carbides play a continuous bridging role between the W-rich, Cr-rich carbides and the FCC solid solution. The microhardness of the coatings increases from 191.8 to 503.4 HV, while the mechanical properties of the interdendritic region are better than those of the dendritic region. Thus, the collaborative wear-resistant effects of multiple carbides provide effective protection against wear. Multi and hierarchical carbides in the CoCrNi/WC composite coating can significantly improve its mechanical properties and wear resistance.

262. Does preoperative bone mineral density impact fusion success in anterior cervical spine surgery: a prospective cohort study

<h3>BACKGROUND CONTEXT</h3> Patients with osteoporosis have an imbalance in anabolic versus catabolic bone homeostasis. It has been theorized that osteoporosis may impact fusion rates in lumbar spine surgery. However, to our knowledge this has not been investigated in cervical spine surgery. As our population ages, we are encountering ever increasing numbers of patients with osteoporosis and osteopenia coming in for elective surgery. <h3>PURPOSE</h3> The purpose of this study is to identify risk factors for pseudarthrosis in patients undergoing anterior cervical spine surgery. <h3>STUDY DESIGN/SETTING</h3> This was a prospective, single-center study conducted at an academic medical center between 2002 and 2018. <h3>PATIENT SAMPLE</h3> Seventy-nine patients who underwent 1-4 level anterior cervical spine fusions between the years of 2002-2018, and had a bone mineral density examination performed preoperatively, completed the study with one year of clinical and radiographic follow-up. <h3>OUTCOME MEASURES</h3> Bone density as measured by T-score, Hounsfield units and fusion status were measured. <h3>METHODS</h3> We prospectively collected and analyzed data on patients undergoing anterior cervical spine fusions involving between 1-4 levels between the years of 2002-2018 in which a bone mineral density (BMD) examination was clinically indicated. Based on the World Health Organization (WHO) classification using DEXA scan for measurement of BMD, normal bone density was defined as T-score greater than or equal to -1 SD, osteopenia as having a T-score less than -1 and greater than -2.5 SD, and osteoporosis as having a T-score less than or equal to -2.5 SD. Patients were followed for a minimum of one year. CT scans performed postoperatively were used to evaluate fusion. Three Hounsfield unit measurements were obtained on the vertebrae above and below the fusion levels and averaged. A total of 79 patients completed the study with one-year of clinical and radiographic follow-up. BMD, number of levels fused, smoking status, age, sex and ACE inhibitors/ARBs were analyzed to assess their impact on fusion success. Fusion was established when there was continuous bone bridging between the vertebrae on CT scan. Multivariate analysis was performed to identify potential risk factors for pseudarthrosis utilizing JMP 10.0.0 statistical software. (SAS Institute Inc, Carey, North Carolina). <h3>RESULTS</h3> Fourteen patients (18%) developed pseudarthrosis at one-year postoperatively. The mean age at surgery was 58.8 ±10.5 (30 to 84 years). The mean BMD was -0.45 ±1.4 (-3 to 4). Osteopenia and osteoporosis were identified as risk factors for pseudarthorsis at a minimum of 1 year follow up. Number of levels fused, smoking status, Hounsfield units, ACE/ARB medications, age or gender were not statistically significant risk factors correlated with development of pseudarthrosis although the study may have been underpowered to detect these differences. <h3>CONCLUSIONS</h3> This study suggests that preoperative osteopenia or osteoporosis may be correlated with a higher incidence of pseudarthrosis in anterior cervical spine surgery, even more so than smoking or number of levels fused. While the number of patients enrolled in this study is small, the results are convincing enough to warrant screening and treatment of osteoporosis as well as the optimization of preoperative bone stock in all potential candidates for cervical spine fusion. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Continuous warfarin administration versus heparin bridging therapy in post colorectal polypectomy haemorrhage: a study protocol for a multicentre randomised controlled trial (WHICH study)

BackgroundEndoscopic removal of colorectal adenoma is considered an effective treatment for reducing the mortality rates associated with colorectal cancer. Warfarin, a type of anticoagulant, is widely used for the treatment and prevention of thromboembolism; however, bleeding may increase with its administration after polypectomy. In recent times, a high incidence of bleeding after endoscopic polypectomy has been reported in patients receiving heparin bridge therapy. However, previous studies have not compared the bleeding rate after endoscopic colorectal polypectomy between patients who continued with anticoagulant therapy and those who received heparin bridge therapy. We hypothesised that endoscopic colorectal polypectomy under the novel treatment with continuous warfarin is not inferior to endoscopic colorectal polypectomy under standard treatment with heparin bridge therapy with respect to the rate of postoperative bleeding. This study aims to compare the efficacy of endoscopic colorectal polypectomy with continuous warfarin administration and endoscopic colorectal polypectomy with heparin bridge therapy with respect to the rate of postoperative bleeding.MethodsWe will conduct a prospective multicentre randomised controlled non-inferiority trial of two parallel groups. We will compare patients scheduled to undergo colorectal polypectomy under anticoagulant therapy with warfarin. There will be 2 groups, namely, a standard treatment group (heparin bridge therapy) and the experimental treatment group (continued anticoagulant therapy). The primary outcome measure is the rate of postoperative bleeding. On the contrary, the secondary outcomes include the rate of cumulative bleeding, rate of overt haemorrhage (that does not qualify for the definition of haemorrhage after endoscopic polypectomy), incidence of haemorrhage requiring haemostasis during endoscopic polypectomy, intraoperative bleeding during endoscopic colorectal polypectomy requiring angiography, abdominal surgery and/or blood transfusion, total rate of bleeding, risk factors for postoperative bleeding, length of hospital stay, incidence of thromboembolism, prothrombin time-international ratio (PT-INR) 28 days after the surgery, and incidence of serious adverse events.DiscussionThe results of this randomised controlled trial will provide valuable information for the standardisation of management of anticoagulants in patients scheduled to undergo colorectal polypectomy.Trial registrationUMIN-CTR UMIN000023720. Registered on 22 August 2016

Fabrication and Characterisation of Aligned Discontinuous Carbon Fibre Reinforced Thermoplastics as Feedstock Material for Fused Filament Fabrication.

In this work, aligned discontinuous fibre composite (ADFRC) tapes were developed and investigated as precursors for a novel 3D printing filament. ADFRCs have the potential to achieve mechanical performance comparable to continuous fibre reinforced composites, given sufficient fibre length and high level of alignment, and avoid many of the manufacturing difficulties associated with continuous fibres, e.g., wrinkling, bridging and corner radii constraints. Their potential use for fused filament fabrication (FFF) techniques was investigated here. An extensive down-selection process of thermoplastic matrices was performed, as matrix properties significantly impact both the processing and performance of the filament. This resulted in four candidate polymers (ABS, PLA, Nylon, PETG) which were used to manufacture ADFRC tapes with a Vf of 12.5% using the high performance discontinuous fibre (HiPerDiF) technology and an in-house developed continuous consolidation module. Tensile stiffness and strength up to 30 GPa and 400 MPa respectively were recorded, showing that a discontinuous fibre filament has the potential to compete with continuous fibre filaments.

Cytosorb filter: An adjunct for survival in the COVID-19 patient in cytokine storm? a case report

COVID-19 is a pandemic that has affected not only the United States, but the entire world. The impact it has had has overwhelmed the entire healthcare system, from the unknown carrier status, poor testing capabilities to hospitals running out of ventilators for severely ill patients. There has been a variety of potential treatment modalities for the various forms of illness ranging from asymptomatic carriers to the ventilated ICU patients. These include anti-inflammatory medications, antibiotics, immune-modulators, convalescent plasma, and others. The cytokine storm that inflicts some patients can be devastating to the vital organs of the human body in the form of acute respiratory distress syndrome (ARDS), renal failure, coagulopathy, and death. Cytosorbents® cytokine filter is a potential treatment methodology aimed at reducing the cytokine storm, thus serving as a bridge for therapy in the acutely ill patients infected with COVID-19. The following case report demonstrates the utility in a critically ill patient who survived the cytokine storm after receiving the cytokine filter via continuous renal replacement therapy bridging him to further definitive therapy.

Observation and analysis of metal transfer phenomena for high-current super-TIG welding process

ABSTRACTSuper-TIG welding is a newly developed TIG welding process using C-type filler metal in TIG welding. In Super-TIG welding, C-filler can prevent the molten pool depression, which is caused by high pressure in the center of the arc during high current TIG welding. In this study, metal transfer modes for C-type filler metal were observed. During these observations, feeding heights were varied for the current of 430 A. It was observed that the stable and continuous bridging transfer along with the arc blow on filler at zero gap feeding height. An intermittent bridging transfer of bridging and separating was repeated at 2 and 4mm height. The arc and filler voltages were low at bridging and high at separating.

An improved crack-bridging model for rigid particle-polymer composites

The incorporation of rigid particles is a promising design strategy to enhance the fracture toughness of polymeric materials. Quantitatively evaluating the toughening effect of particles is crucial for thoroughly exploring the full potential of such a strategy. In this paper, an improved crack-bridging model is proposed to correlate the fracture toughness of rigid microparticle-reinforced polymer composites with their microstructure. The critical stress intensity factor (SIF) is used to describe the fracture toughness of composites. The critical SIF values of composites rely on the critical SIF of the polymer matrix and the SIF induced by the bridging particles. The discrete bridging forces induced by particles are treated as the continuous bridging stresses. The bridging-SIF is determined by the integration of bridging stress. Theoretical predictions revealed that increasing the particle volume fraction and the particle-matrix interfacial strength can effectively improve the fracture toughness of polymeric materials. For the polymer reinforced with micron-sized particles, the fracture toughness increases with increased particle size. The theoretical results predicted by our model agree well with the experimental data. Our results help to elucidate the dependence of the fracture toughness of particle-polymer composites on their microstructure and therefore are useful for the design and optimization of advanced composite materials.

Patterns of Spinal Fusion after Anterior Cervical Discectomy and Fusion with Polyether Ether Ketone Cage Filled Hydroxyapatite

Background Data: ACDF is one of the most commonly performed operations for degenerative spinal diseases. Traditionally, graft was harvested from iliac crest which was associated with donor site morbidity. This has led to the introduction of many synthetic implants such as PEEK cages to overcome this problem.Purpose: To evaluate the patterns of spinal fusion after ACDF with PEEK cage filled with HA.Study Design: Retrospective clinical study.Patients and Methods: Twenty-five patients that underwent ACDF with PEEK cage filled HA were enrolled in this study through the period from January to December 2017. All patients were submitted to pre- and postoperative clinical and radiological follow-up. Postoperative full neurological and images evaluations were done by independent observer on outpatients at 1, 2, 3, 6, and 12 months. Postoperative neck pain was evaluated using VAS. Radiological evaluation was done using cervical X-ray and images were evaluated using software SurgimapTM.Results: The mean age of our patients was 44.4±6.57 with 9 patients being males and 16 patients females. Total numbers of levels reported were 33 in 25 patients, with 17 patients (68%) undergoing single-level ACDF and 8 patients (32%) double-level ACDF. Five patients (20%) suffered from myeloradiculopathy and twenty patients (80%) had radiculopathy. The mean follow-up was 11.04±1.2. The mean preoperative neck pain VAS was 7.8±1.9, while postoperative VAS was 2.9±1.8. Continuous bridging bony trabeculae were reported in 29 levels (87.9 %) (N=21), while they were absent in 4 levels (12.1%) (N=4). Cage migration was reported in two patients (6%) and both showed >2 mm mobility in dynamic cervical X-ray indicating instability and nonunion.Conclusion: ACDF with PEEK cage filled with HA is a safe and effective method to achieve interbody fusion in patients with cervical disc disease. Although fusion occurred within usual time, remodeling took longer time than that previously reported with iliac graft (2018ESJ171).

Arc characteristics and metal transfer modes in arcing-wire gas tungsten arc welding

Arcing-wire gas tungsten arc welding is an innovative process developed as a variant of gas tungsten arc welding to reinforce the deposition rate by utilizing bypass arc energy. After establishing an experimental platform, the experiments were conducted to study the arc characteristics, interaction of the main and bypass arcs, and metal transfer behavior. Magnetic arc blow, location of the bypass arc root, and shielding gas flow were found to cause arc deflection and an invisible obstacle between the arcs in arcing-wire gas tungsten arc welding. The bypass arc voltage should be controlled carefully to maintain the stability of the welding process. Globular transfer, short-circuiting transfer, and continuous bridging transfer could be obtained, which were determined by wire feed speed (the melting current) and the distance from the wire tip to the workpiece as well as the welding direction.