Application Of Fixation Research Articles

Biomechanical stability of magnesium plate and screw fixation systems in LeFort I osteotomy: a three-dimensional finite element analysis

BackgroundTitanium (Ti–6Al–4 V) is used for fixation in LeFort I osteotomy, a procedure for treating midface deformities. This study assessed the biomechanical stabilities of two Mg alloys (WE43 and ZK60) as biodegradable alternatives and compared them against Ti using finite element analyses. The LeFort I osteotomy procedure was simulated, and various plate and screw configurations were tested. The maximum principal and peak von Mises stresses in the metal plates and bone screws were measured under four load conditions, and the stability was evaluated.ResultsThe holes in the Mg screws, as compared with the Ti counterparts, exhibited higher and lower stress levels in the cortical and cancellous bones, respectively. The Mg screws also exhibited a higher fracture risk. The ZK60 plate, as compared with the Ti and WE43 plates, exhibited a lower fracture risk under all load conditions. ZK60 exhibited higher biomechanical stability in terms of maintaining the gap between osteotomy surfaces and lower fracture risk; the osteotomy surfaces with Ti im-plants underwent bone impaction, resulting in gap closure.ConclusionsAlthough the Mg implants exhibited better stress distribution, their screw strength requires improvement. Appropriate improvements can promote the use of Mg alloys in bone fixation applications.

Demineralized cancellous bone scaffolds as reinforcement for degradable magnesium biocomposite

AbstractThis study investigates demineralized bone matrix (DBM) combined with magnesium (Mg) to create degradable composite materials. Two types of DBM were utilized: carbon-coated (H.A.) and non-carbon-coated (HA-HT). An advanced liquid metal infiltration method prevented the structural collapse of the scaffold due to capillary forces. Both composites exhibited an interphase layer primarily composed of MgO, differing in thickness by 50%, attributed to the reaction between H.A. and Mg. The Mg/H.A. composite demonstrated a compressive yield strength 1.7 times higher than Mg/HA-HT, resembling Mg’s mechanical behavior but with a lower metal phase fraction than other composites. Compared to pure Mg, the composites generated less hydrogen (45–54 ml cm−2), reducing the corrosion rate (~ 0.1181 mm year−1) under simulated conditions (90 ml cm−2 and 4.2 mm year−1 for Mg). A localized phenomenon was identified mainly at the interphase of both composites but specifically in the Mg/H.A., where the scaffold structure was kept over extended exposure periods. These materials hold promise for temporary bone fixation applications. Graphical abstract

A Newly Predicted Magnetic TMB6 Monolayer for Efficient Nitrogen Fixation.

Developing electrocatalysts for the N2 reduction reaction (NRR) with high activity, high selectivity, and low cost is urgently required to enhance the NH3 yield rate. Based on first-principles calculations, we predict a series of new transition metal boride TMB6 (TM = Ti, V, Cr, Mn, Fe, and Co) monolayers and investigate their magnetoelectronic and electrocatalytic properties. The results reveal that VB6 and CoB6 favor ferromagnetic coupling, while TiB6, CrB6, MnB6, and FeB6 display antiferromagnetic ordering. Furthermore, TiB6 exhibits a high Néel temperature of 344 K and a large magnetic anisotropy energy of 614 μeV per Ti atom. Most interestingly, TiB6 and VB6 exhibit superior NRR catalytic activity with a limiting potential of -0.50 and -0.19 V, respectively, and favorable NRR selectivity over the HER. Finally, the structural stability of TMB6 monolayers has been confirmed by a set of phonon dispersion, molecular dynamics, and elastic constant calculations. Our results highlight the use of the newly designed two-dimensional (2D) TM borides as promising candidates for spintronic devices and nitrogen fixation applications.

Application of anterior esophageal wall full layer fixation and gastric tube guidance in total laparoscopic overlap method for intracorporeal esophagojejunostomy

Objective: To explore the application of anterior esophageal wall full layer fixation and gastric tube guidance in total laparoscopic overlap method for intracorporeal esophagojejunostomy. Methods: Overlap esophagojejunostomy with anterior esophageal wall full layer fixation and gastric tube guidance is suitable for patients with advanced gastric cancer (clinical stage: cT1b~4aN0~3M0) and esophageal invasion <3 cm, who underwent radical total gastrectomy+ overlap esophagojejunostomy. The main operation procedure was performed as follows: A titanium clip was used for fixation of the full anterior wall of esophagus before overlap esophagojejunostomy, and the side-to-side esophagojejunostomy was performed with the linear stapler under the guidance of gastric tube. Then the titanium clip was removed after confirming that the correct cavity was entered. Finally, the common outlet was closed by two barbed sutures. A descriptive case series study was conducted. The clinical data of patients who underwent laparoscopic radical gastrectomy and overlap esophagojejunostomy with anterior esophageal wall full layer fixation and gastric tube guidance in Guangdong Provincial Hospital of Chinese medicine and the First Affiliated Hospital of Guangzhou University of Chinese medicine from May 2021 to June 2023 were retrospectively analyzed. Results: A total of 42 patients were collected, and all of them were successfully completed laparoscopic total radical gastrectomy without conversion to laparotomy or perioperative death. The esophagojejunostomy time, operative time, intraoperative blood loss was 17(5-25) minutes, (258.8±38.0) minutes and 50(20-200) ml, respectively. The incidence of esophageal false lumen was 0%, and there were no intraoperative complications. The time of gastric tube removal, initial fluid diet intake and the duration of postoperative hospital were 2(1-5) , 4(1-8) and 8(4-21) days, respectively. There were no postoperative anastomotic hemorrhage, anastomotic stenosis and other related complications. One patient (2.38%) developed a Clavien-Dindo IIIb complication, which was abdominal hemorrhage after operation. The second surgical exploration confirmed that the patient was bleeding due to gastroduodenal artery rupture. After intraoperative suture hemostasis, fluid expansion, blood transfusion and other treatments, the patient was discharged on the 15th day after the operation. Three patients (7.14%) developed Clavien-Dindo grade II complications, including anastomotic leakage, chylous leakage and pulmonary infection, and were discharged after conservative treatment such as anti-infection and prolonged retention of drainage tube. Conclusions: Laparoscopic overlap method for intracorporeal esophagojejunostomy with anterior esophageal wall fixation and gastric tube guidance can shorten the time of esophagojejunostomy and prevent the occurrence of false lumen, and do not increase anastomose-related complications.

Three-dimensional acetabular reorientation during periacetabular osteotomy: an intraoperative navigation method using an external fixator for periacetabular osteotomy.

Bernese periacetabular osteotomy (PAO) is an effective procedure for treating acetabular dysplasia. However, limited visual control of the acetabular position during surgery may result in under- or overcorrection or changes in acetabular version resulting in residual dysplasia or femoroacetabular impingement. Thus, we wanted to develop a simple and straightforward navigation method that provides information about acetabular correction in all three planes during surgery. Intraoperatively, acetabular coordinates are shown in coronal, sagittal, and transverse plane by two perpendicular tubes of an external fixator mounted onto a third tube that is fixed to the mobilized acetabular fragment with two Schanz screws. The application and fixation of the external fixator on the pelvis are demonstrated in this article. We used this analog navigation method on 27 PAOs, where we mainly performed a lateral rotational correction. The pre- and postoperative radiographs of these 27 hips were analyzed regarding the radiological hip parameters, taking into account the pelvic tilt. The mean preoperative lateral center edge angle (LCEA) of the 27 PAOs improved from 16° (+-6) to a mean of 34° (+-6°) and the mean acetabular index (AI) was corrected from 15° (+-4) to 2° (+-4). This implements highly physiologic postoperative values for lateral coverage in this population. In this case series, no postoperative acetabular retroversion was measured in any of the 27 PAOs. Three-dimensional control of the acetabular orientation during periacetabular osteotomy is important to avoid over- and undercorrection. Using a fixateur externe as an analog navigation method this three-dimensional control can be implemented intraoperatively for PAOs.

Advancing the design of interspinous fixation devices for improved biomechanical performance: dual vs. single-locking set screw mechanisms and symmetrical vs. asymmetrical plate designs.

Interspinous devices were introduced in the field of spine surgery as an alternative to traditional pedicle screw fixation in selected patients for treatment of spinal stenosis and fixation. These devices designs have evolved from non-fixated extension blocks to sophisticated interspinous fixation devices (IFDs). There is an absence of literature comparing the biomechanical fixation strength of different IFD plate designs and the role of set screw locking systems. The aim of this study was to evaluate fixation strengths by bench testing static disassembly and pullout strength of two dissimilar IFD designs and locking mechanisms. We hypothesized that the InSpan (InSpan LLC, Burlington, MA, USA) dual-locking symmetrically IFD plate designed will have stronger fixation than the Aspen (ZimVie, Parsippany, NJ, USA) single-locking asymmetric IFD plate design. We conducted two biomechanical bench tests to evaluate the load to failure locking characteristics of symmetrical InSpan and asymmetrical Aspen IFD designs. Static pullout testing involved locking each IFD to the stainless steel and 40 pcf cellular polyurethane foam and measuring pullout load and displacement six times. Seven InSpan and two Aspen IFDs (including the "used" IFDs from the pullout testing) underwent static disassembly tests using a pair of disassembly fixtures positioned between the IFD plates to measure disassembly force and displacement. All tests were performed under ambient conditions using an INSTRON 8874 Bi-Axial Tabletop Servohydraulic Dynamic Testing System (INSTRON, Norwood, MA, USA), and data was collected at a 0.2 mm/s displacement control rate until the test was stopped when there was a drop in the continuously increasing force against resistance (gross failure). The InSpan IFD experienced 94.81% higher resistance to pullout compared to the Aspen IFD in static pullout testing (P<0.05), owing to its notably larger footprint area of 69.8%. Gross failure for both IFD implant designs occurred at the foam block-block interface. In static disassembly testing, pristine InSpan required 60.7% higher force over pristine Aspen and 401.3% for "used" IFDs. Gross failure was characterized by the gradual distraction of the plates and material removal at the set screw contact points. Implant failure at the block-implant interface emphasized the pivotal role of teeth design and the contact surface area of the plates in ensuring stability. The dual-locking symmetrical InSpan IFD outperformed single-locking asymmetric Aspen IFD in both static disassembly and pullout bench tests. This highlights the benefits of InSpan's improved design and its potential for enhanced long-term stability in spinal fixation applications.

Bone healing under different lay-up configuration of carbon fiber-reinforced PEEK composite plates.

Secondary healing of fractured bones requires an application of an appropriate fixator. In general, steel or titanium devices are used mostly. However, in recent years, composite structures arise as an attractive alternative due to high strength to weight ratio and other advantages like, for example, radiolucency. According to Food and Drug Administration (FDA), the only unidirectionally reinforced composite allowed to be implanted in human bodies is carbon fiber (CF)-reinforced poly-ether-ether-ketone (PEEK). In this work, the healing process of long bone assembled with CF/PEEK plates with cross- and angle-ply lay-up configurations is studied in the framework of finite element method. The healing is simulated by making use of the mechanoregulation model basing on the Prendergast theory. Cells transformation is determined by the octahedral shear strain and interstitial fluid velocity. The process runs iteratively assuming single load cycle each day. The fracture is subjected to axial and transverse forces. In the computations, the Abaqus program is used. It is shown that the angle-ply lamination scheme of CF/PEEK composite seems to provide better conditions for the transformation of the soft callus into the bone tissue.

The value of computer reconstruction in the treatment of intra-articular fractures of the distal part of the humerus

The aim of the work was to study the role of computer reconstruction and additive technologies in the planning of surgical treatment of intra-articular fractures of the distal part of the humerus in the early post-traumatic period. Materials and methods: the results of treatment of 44 patients with fractures of the distal part of the humerus aged from 22 to 65 years were studied. All patients underwent MSCT in the preoperative period. In 45.5 % (20) cases, in order to increase the effectiveness of preoperative planning, simulation osteosynthesis was performed on an individual printed model of the damaged bone. After completion of preoperative planning, all patients underwent osseous metallo-osteosynthesis in the first week after receiving the injury. In order to assess the effectiveness of the application of visualization techniques, a survey of the operating team was carried out regarding the informativeness of the conducted instrumental studies. Results. The average duration of surgical intervention among patients in the clinical group with standard preoperative planning was 105.9 ± 9.15 minutes. The average results of the survey of the surgical team after the surgical interventions in the specified clinical group were 21.2 ± 2.8 points. The average duration of surgery among patients of the second clinical group, whose preoperative planning included not only the assessment of MSCT results of the damaged segment, but also simulated osteosynthesis with the selection and application of optimal metal fixators, was 54.6 ± 7.14 minutes. The average results of the survey of the surgical team were 31.2 ± 1.7 points. Conclusions. The use of a combination of visualization technologies and 3D printing allows to reduce the time the patient spends in the operating room and increase the effectiveness of preoperative planning. Performing simulated osteosynthesis in the preoperative period allows you to develop an individual technique of repositioning bone fragments and use the optimal standard size of the cortical metal fixator with the distribution of the most favourable compression points of bone fragments

Application of external fixator combined with Kirschner wire fixation for oblique and comminuted distal humeral metaphyseal-diaphyseal junction fractures in children

To analyze the effectiveness of external fixator combined with Kirschner wire (EF-KW) fixation in the treatment of oblique and comminuted distal humeral metaphyseal-diaphyseal junction (DHMDJ) fractures in children. A clinical data of 22 children with DHMDJ fractures who met the selection criteria between April 2021 and December 2023 was retrospectively analyzed. All patients were treated with EF-KW fixation. There were 14 boys and 8 girls with an average age of 6.8 years (range, 1.5-12.0 years). The time from injury to operation was 14-38 hours (mean, 24.2 hours). There were 18 cases of comminuted fractures and 4 cases of oblique fractures; and 1 case of median nerve injury and 1 case of radial nerve injury before operation. The occurrence of postoperative complications was recorded. At last follow-up, the function of the affected elbow joint was evaluated according to the Mayo elbow joint function score, and the Baumann's angle (BA) and humero-capitellar angle (HCA) of the affected and healthy sides were recorded and compared. All fractures were successfully treated with closed reduction and no complications such as nerve injury occurred. Superficial infection occurred in 4 cases after operation and healed after symptomatic treatment. The incisions of other patients healed by first intention. All patients were followed up 9-24 months (mean, 13.8 months). At last follow-up, according to the Mayo elbow joint function score, the elbow joint function was rated as excellent in 15 cases, good in 6 cases, and fair in 1 case, with an excellent and good rate of 95.5%. The neurologic injury before operation recovered gradually. X-ray films reexamination showed that all fractures healed, and the healing time of fractures ranged from 29 to 61 days, with an average of 35.6 days. At last follow-up, there was no significant difference in BA and HCA between the healthy side and the affected side ( P>0.05). During follow-up, 1 case developed mild cubitus varus, while the other patients had no serious complications. EF-KW fixation for oblique and comminuted DHMDJ fractures in children has the advantages of less trauma, simple operation, easy reduction, good stability after reduction, low incidence of serious complications, and good elbow functional recovery.

Experience in early minimally invasive fixation of pubic symphysis disruption with a system of transpedicular screws in patients with combined pelvic trauma (pilot study)

Introduction Challenges of treating the injuries of pubic symphysis in patients with combined pelvic injury require developing new techniques for stable minimally invasive osteosynthesis in the acute period of trauma.Purpose of the work was to assess the application of low invasive fixation of the pubic symphysis with a system of transpedicular screws in the patients with combined unstable pelvic injuries in the acute period of the traumatic disease.Materials and methods The results of treatment of 12 patients with polytrauma with unstable pelvic injury with rupture of the pubic symphysis who were treated at Dzhanelidze Research Institute of Emergency Medicine, St. Petersburg, in the period from 2017 to 2023, were analyzed. All the patients underwent final minimally invasive fixation of the pubic symphysis with a system of transpedicular screws in the early period of the traumatic disease.Results The overall assessment of the results in 12 patients found no complications or technical errors during the installation of transpedicular screws. Control CT scans of the pelvis showed that osteosynthesis was stable in all patients, and the position of metal was correct in all. One patient from the study group died in the clinic from massive pulmonary embolism. The long-term results in 11 patients in the period from 6 months to 3 years after trauma were evaluated as excellent and good anatomical and functional results in 10 patients, one case had fair outcome.Discussion The use of bone plates to fix ruptures of the symphysis pubis leads to disruption of its physiological mobility, and the patient’s activity in the postoperative period can cause an implant fracture. Original dynamic plates and wire cerclage help avoid this complication; however, all these techniques involve significant surgical trauma and blood loss, as well as the risk of postoperative wound suppuration. Minimally invasive methods of fixation using cannulated screws, systems such as Endobutton, Tight Rope can reduce intraoperative trauma and the risk of complications (blood loss, suppuration); however, the procedure for their installation is quite complex and lengthy, and for greater stability, external fixation of the pelvic ring is often required. The proposed minimally invasive fixation of the pubic symphysis with a system of transpedicular screws avoids a lot of shortcomings and is sufficiently stable.Conclusion The method of minimally invasive fixation of the pubic symphysis with a system of transpedicular screws meets current requirements in the treatment of patients with polytrauma and unstable pelvic injury, and it may be successfully used in the acute period of trauma.

Efficacy of virtual surgical planning and a three-dimensional-printed, patient-specific reduction system to facilitate alignment of diaphyseal tibial fractures stabilized by minimally invasive plate osteosynthesis in dogs: A prospective clinical study.

To evaluate the efficacy of a three-dimensional (3D)-printed, patient-specific reduction system for aligning diaphyseal tibial fractures stabilized using minimally invasive plate osteosynthesis (MIPO). Prospective clinical trial. Fifteen client owned dogs. Virtual 3D models of both pelvic limbs were created. Pin guides were designed to conform to the proximal and distal tibia. A reduction bridge was designed to align the pin guides based on the guides' spatial location. Guides were 3D printed, sterilized, and applied, in conjunction with transient application of a circular fixator, to facilitate indirect fracture realignment before plate application. Alignment of the stabilized tibiae was assessed using postoperative computed tomography scans. Mean duration required for virtual planning was 2.5 h and a mean of 50.7 h elapsed between presentation and surgery. Guide placement was accurate with minor median discrepancies in translation and frontal, sagittal, and axial plane positioning of 2.9 mm, 3.6°, 2.7°, and 6.8°, respectively. Application of the reduction system restored mean tibial length and frontal, sagittal, and axial alignment within 1.7 mm, 1.9°, 1.7°, and 4.5°, respectively, of the contralateral tibia. Design and fabrication of a 3D-printed, patient-specific fracture reduction system is feasible in a relevant clinical timeline. Intraoperative pin-guide placement was reasonably accurate with minor discrepancies compared to the virtual plan. Custom 3D-printed reduction system application facilitated near-anatomic or acceptable fracture reduction in all dogs. Virtual planning and fabrication of a 3D-printing patient-specific fracture reduction system is practical and facilitated acceptable, if not near-anatomic, fracture alignment during MIPO.

Research Progress on the Application of MOF and MOF‐Based Materials in Nitrogen Reduction

AbstractElectrocatalytic and photocatalytic nitrogen fixation have become new ways to achieve green nitrogen reduction because of their environmentally friendly and cost‐effective characteristics. At present, there has been an increasing curiosity about using metal‐organic frameworks (MOFs) for photocatalysis and electrocatalysis. However, electrocatalytic and photocatalytic ammonia production is still not practical for practical applications. Having a thorough understanding of nitrogen fixation is necessary for the advancement of practical applications and the development of highly efficient catalysts in the future. The catalytic nitrogen fixation activity of MOF itself is limited. By adjusting the exposure of active sites through low‐temperature calcination and solvent addition, the photogenerated carrier recombination is inhibited, and the adsorption and activation of N2 are enhanced, improving its performance in nitrogen fixation applications. This review examines the reported photocatalysts, electrocatalysts, and photoelectrocatalysts based on MOFs and their associated materials. The underlying mechanism for photocatalysis and electrocatalysis is elucidated. Additionally, an inclusive survey of MOFs and related materials as catalysts for nitrogen reduction reaction (NRR) is presented, with representative examples discussed. Finally, the research progress of MOF‐based catalytic nitrogen fixation materials is summarized and prospected.

Epoxidized Soybean Oleic Acid/Oligomeric Poly(lactic acid)-Grafted Nano-Hydroxyapatite and Its Role as a Filler in Poly(L-lactide) for Potential Bone Fixation Application.

One of the most effective strategies for modifying the surface properties of nano-fillers and enhancing their composite characteristics is through polymer grafting. In this study, a coprecipitation method was employed to modify hydroxyapatite (HAP) with epoxidized soybean oleic acid (ESOA), resulting in ESOA-HAP. Subsequently, oligomeric poly(lactic acid) (OPLA) was grafted onto the surface of ESOA-HAP, yielding OPLA-ESOA-HAP. HAP, ESOA-HAP, and OPLA-ESOA-HAP were comprehensively characterized. The results demonstrate the progressive grafting of ESOA and OPLA onto the surface of HAP, resulting in enhanced hydrophobicity and improved dispersity in organic solvent for OPLA-ESOA-HAP compared to HAP. The vitality and adhesion of Wistar rat mesenchymal stem cells (MSCs) were assessed using HAP and modified HAP materials. Following culture with MSCs for 72 h, the OPLA-ESOA-HAP showed an inhibition rate lower than 23.0% at a relatively high concentration (1.0 mg/mL), which is three times lower compared to HAP under similar condition. The cell number for OPLA-ESOA-HAP was 4.5 times higher compared to HAP, indicating its superior biocompatibility. Furthermore, the mechanical properties of the OPLA-ESOA-HAP/PLLA composite almost remained unaltered ever after undergoing two stages of thermal processing involving melt extrusion and inject molding. The increase in the biocompatibility and relatively high mechanical properties render OPLA-ESOA-HAP/PLLA a potential material for the biodegradable fixation system.

Do Patients Achieve "Full Weight-bearing" Immediately Following Application of Circular Frame Fixation of the Lower Limb?

The decision to use circular frame fixation for lower limb trauma, or elective deformity correction, often accompanies the assertion that the patient will be able to fully weight-bear through the limb immediately following surgery. About 53 patients underwent retrospective review. Included in the study were current attendees of adult specialist physiotherapy, following circular frame application to the lower leg at our Institution between August 2018 and January 2020. Cases with incomplete data, cases given postoperative status of non-weight-bearing, those with physiotherapy follow-up conducted elsewhere, or cases of polytrauma were excluded from the study.Weight-bearing assessment and rehabilitation supervision were at the discretion of the physiotherapy team. The clinical concept of 'full weight-bearing' is poorly defined, but was documented in the context of displaying a stable gait using elbow crutches and subsequently without walking aids. Comparative data was analysed using an unpaired, two-tailed Welch's t-test. Mean postoperative time to full weight-bearing using crutches was 28.3 days (0-159) (n = 40).Mean postoperative time to independent full weight-bearing with no walking aids was 230.6 days (35-393), or 7.1 months (0-12) (n= 34).No significant differences were seen between:Frames for open injuries (n= 5) vs closed injuries (n = 17; p > 0.4).Joint-spanning constructs (n= 18) vs non-spanning constructs (n = 21; p > 0.6), orTreatment of intra-articular injuries (n = 14) vs extra-articular injuries (n = 17; p > 0.2).Interpretation of these results should be made with caution due to sample size. The ability to permit patients to fully weight-bear immediately after surgery is often a distinct advantage of the circular frame over other fixation modalities, for a variety of indications. However, it does not follow that patients are capable of doing so; there is a long dependency on walking aids. This would appear to be the case irrespective of open/closed injuries, intra-/extra-articular injuries, or the use of a spanning construct across the knee or ankle. Craig A, Barron E, Sharma H, et al. Do Patients Achieve "Full Weight-bearing" Immediately Following Application of Circular Frame Fixation of the Lower Limb? Strategies Trauma Limb Reconstr 2024;19(1):40-44.

Preparation of Magnetic Nano-Catalyst Containing Schiff Base Unit and Its Application in the Chemical Fixation of CO2 into Cyclic Carbonates

The development of a catalyst for the conversion of CO2 and epoxides to the corresponding cyclic carbonates is still a very attractive topic. Magnetic nano-catalysts are widely used in various organic reactions due to their magnetic separation and recycling properties. Here, a magnetic nano-catalyst containing a Schiff base unit was designed, synthesized and used as a heterogeneous catalyst to catalyze CO2 and epoxides to form cyclic carbonates without solvents and co-catalysts. The catalyst was characterized using Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric (TG), VSM, SEM, TEM and BET. The results show that the magnetic nano-catalyst containing the Schiff base unit has a high activity in the solvent-free cycloaddition reaction of CO2 with epoxide under mild conditions, and is easily separated from the reaction mixture driven by external magnetic force. The recovered catalyst maintains a high performance after five cycles.

Rhizobium leguminosarum bv.viciae Potential Assessment using Dosha faba Bean Isolates from Central and North Gondar, Ethiopia

Purpose: The objective this study was to evaluate nitrogen fixation effectiveness, survival and compatibility of the isolates of on two different soils that came from Dabat and Shentia sites at Gondar, Ethiopia. The author recommends that the isolates test their nitrogen fixing potential under field conditions in slightly acidic and neutral soil before being used as commercial biofertilzer inoculants. The present study provides potential nitrogen fixer input for agricultural research centers. Methodology: Soil physicochemical analysis and most probable number were done according to their standard procedure. Three top strains were selected as inoculants for faba beans grown on the slightly acidic Shentia soil and the slightly neutral Dabat soil with their control. The symbiotic effectiveness of the strains was evaluated based on plant agronomy and total nitrogen of the plant. The results of the strains analyzed by SPSS version 26. Findings: The highest rhizobium population size was 5.8 x102 cells g-1 soil, while the lowest was 1.7 x102 cell g-1 soil observed at the Dabat and Shentia sites, respectively. There is limited nitrogen and phosphorus content other were enough. It was significant difference inter-strain difference in the all agronomic parameter of all treatments in soil compared to each based on agronomic parameter, but across soils there was no significant different except shoot fresh weight. The result of these studies showed that two Rhizobium leguminosarum bv.viciae isolates and other combinations of them had considerable effect on agronomic properties. Unique Contribution to Theory, Practice and Policy: The application of biological nitrogen fixation through Rhizobium inoculums is promoted as a solution to the problem of poor soil fertility in areas where legumes are cultivated. In most of the developing countries, including Ethiopia, biological nitrogen fixation technology has not fully flourished, so this study was initiated to evaluate fixation potential of isolates.

Ozone decomposition on transition-metal-atom anchored graphdiyne: Insights from computation and experiment

Transition-metal-atom anchored graphdiynes (TM@GDY, TM = Mn, Fe, Co, Ni and Cu) have already been synthesized and found applications in hydrogen evolution, nitrogen fixation and etc. By means of first-principle predictions and test experiments, we propose here that Fe@GDY and Co@GDY are efficient catalysts for the sustainable conversion of O3 to O2. These two catalysts can spontaneously chemisorb O3 with zero reaction barrier and have low O3 conversion barriers (0.31 eV and 0.19 eV, respectively). The O3 decomposition experiment in a continuous flow membrane reactor and electron paramagnetic resonance results verify that Fe@GDY and Co@GDY are efficient catalysts under humid conditions. Raman spectra prove the formation of the key Fe-O/Co-O and FeOO and CoOO intermediates. The hydrophobic nature of graphdiyne and the strongest chemisorption of O3 among tested ambient gases, make Fe@GDY and Co@GDY ideal catalysts under both dry and humid conditions. These findings would stimulate future explorations on metal anchored GDY-based catalysts for applications of toxic gas decomposition or fixation.

Nitrogen Fixation via Plasma-Assisted Processes: Mechanisms, Applications, and Comparative Analysis—A Comprehensive Review

Nitrogen fixation, the conversion of atmospheric nitrogen into biologically useful compounds, is crucial for sustaining biological processes and industrial productivity. Recent advances have explored plasma-assisted processes as an innovative approach to facilitate nitrogen fixation. This review offers a comprehensive summary of the development, current state of the art, and potential future applications of plasma-based nitrogen fixation. The analysis encompasses fundamental principles, mechanisms, advantages, challenges, and prospects associated with plasma-induced nitrogen fixation.

Application of double plate fixation combined with Masquelet technique for large segmental bone defects of distal tibia: a retrospective study and literature review.

There is no effective consensus on the choice of internal fixation method for the Masquelet technique in the treatment of large segmental bone defects of the distal tibia. Thus, the study aimed to investigate the outcomes of the Masquelet technique combined with double plate fixation in the treatment of large segmental bone defects. This was a retrospective study involving 21 patients with large segmental bone defects of the distal tibia who were treated between June 2017 and June 2020. The length of bone defect ranged from 6.0cm to 11cm (mean, 8.19cm). In the first stage of treatment, following complete debridement, a cement spacer was placed to induce membrane formation. In the second stage, double plate fixation and autologous cancellous bone grafting were employed for bone reconstruction. Each patient's full weight-bearing time, bone healing time, and Iowa ankle score were recorded, and the occurrence of any complications was noted. All patients were followed up for 16 to 26months (mean, 19.48months). The group mean full weight-bearing time and bone healing time after bone grafting were 2.41 (± 0.37) months and 6.29 (± 0.66) months, respectively. During the treatment, one patient had a wound infection on the medial side of the leg, so the medial plate was removed. The wound completely healed after debridement without any recurrence. After extraction of iliac bone for grafting, one patient had a severe iliac bone defect, which was managed by filling the gap with a cement spacer. Most patients reported mild pain in the left bone extraction area after surgery. The postoperative Iowa ankle score range was 84-94 (P < 0.05). In this cohort, 15 cases were rated as "excellent", and 6 cases as "good" on the Iowa ankle scoring system. The Masquelet technique combined with double plate fixation is a safe and effective method for the treatment of large segmental bone defects of the distal tibia.

Temporary Cast Application in Dislocated Ankle Fractures Leads to High Rates of Secondary Loss of Reduction: Does the Lauge-Hansen Injury Type Matter?

For the temporary treatment of ankle fracture dislocations (AFDs), previous studies indicate higher rates of secondary loss of reduction (LOR) with splint immobilization, prompting consideration for expanding indications for external fixation (ExFix). However, these studies did not investigate the influence of fracture morphology to further improve patient selection. The aim of this study was to investigate the influence of Lauge-Hansen injury type on the LOR rate in bimalleolar or trimalleolar AFDs for temporary cast vs ExFix immobilization. In this retrospective cohort study, patients with isolated AFD cases treated at our institution from 2011 to 2020 were reviewed. Inclusion criteria required radiographs depicting initial dislocation and appropriate reduction after Cast or ExFix immobilization. Exclusion criteria encompassed concomitant injuries, open fractures, conservative management as well as surgery performed within 48 hours or at a different facility. Patients were grouped by temporary treatment (Cast or ExFix). The primary endpoint was LOR prior to definitive surgery across various Lauge-Hansen types. The LOR rate was significantly higher in the cast group (40/152, 26.3%) compared to the ExFix group (5/191, 2.6%; P < .0001). In the cast group, LOR was associated with an increase in time to definitive surgery by a mean of 3 days (P < .002). During cast treatment, LOR was significantly more likely for pronation abduction (P = .001) and supination external rotation injuries (P < .0001), whereas no significant differences were observed for pronation external rotation (P = .006), supination adduction (P > .99), and fractures not classifiable (P > .99). In cases of AFDs resulting from supination external rotation or pronation abduction trauma according to the Lauge-Hansen classification, especially in the setting of an additional posterior malleolar fracture, primary application of external fixation should be considered to reduce the risk for secondary loss of reduction. Level III, retrospective cohort study.